- 

NASA Conference Publication 2276 

First Symposium on ,,I; 

Chemical Evolution @ - 

and the Origin and ‘L-z 

Evolution of Life 

LOAN CDPY:RETURN TO 

AFWLTECHNICAL LIEXARY 

Kli?TIAND AFB&M. 

Proceedings of a symposium held at 

NASA Ames Research Center 

Moffett Field, California 

August 24, 1982 

25th Anniversary 

1958-1983 
TECH LIBRARY KAFB, NM 

llllllllllllllllll~~lm

oossi4s NASA Conference Pubis,,,,,., yy, v 

First Symposium on 

Chemical Evolution 

and the Origin and 

Evolution of Life 

Edited by 

Donald L. DeVincenzi 

NASA Headquarters 

Washington, D.C. 

Linda G. Pleasant 

The George Washington University 

Medical Center 

Washington, D. C. 

Proceedings of a symposium sponsored by the 

National Aeronautics and Space Administration 

and the International Society for the 

Study of the Origin of Life and held at 

NASA Ames Research Center 

Moffett Field, California 

August 2-4, 1982 

National Aeronautics 

and Space Administration 

Scientific and Technical 

information Branch 

1983 

Contents 

Introduction ...................................................... 1 

Background ........................................................ 2 

Symposium Program ................................................. 4 

Scientific Session Summaries ...................................... 13 

Abstracts 

Session I: Extraterrestrial Chem i stry .......................... 37 

Session II: Primitive Earth..... . .............................. 47 

Session III: Information Transfer .............................. 

Session IV: Solar System Exploration ........................... 

Session V: Planetary Protection ................................ 

Session VI: Future Directions .................................. 

Session VII: Geological Record ................................. 

Session VIII: Early Biological Evolution ....................... 

Author Index ...................................................... 

Appendix - Participant List ....................................... 

59 

68 

73 

75 

81 

91 

102 

106 

iii 
Introduction 

This report contains session summaries and abstracts from the "First 

Symposium on Chemical Evolution and the Origin and Evolution of Life," 

organized by Donald L. DeVincenzi, held August 2-4, 1982 at NASA' s Ames 

Research Center, Moffett Field, CA. 

The symposium provided an opportunity for all NASA Exobiology principal investigators to present their most recent research in a scientific 

meeting forum. In addition, the symposium attempted to foster increased 

communication across disciplinary lines, formulate a more integrated program approach, review progress in all tasks, and increase visibility of 

the Exobiology Program. 

The more than 150 participants (see Appendix) included Exobiology 

grantees, ARC staff, graduate students, and invited guests. 

Current plans are to schedule this symposium approximately every three 

years as part of a series of meetings. This series might include the College Park Colloquia and meetings of the International Society for the Study 

of the Origin of Life. 

Further information about NASA's Exobiology Program, including a yearly 

listing of all scientific papers from program-sponsored research, can be 

found in the annual "Publications of the Exobiology Program," obtainable 

from the NASA Headquarters Program Office. 

1 
Background 

NASA's Exobiology Program seeks to understand the origin, evolution and 

distribution of life, and life-related molecules, on Earth and throughout 

the universe. The program is intriguing because of the fundamental question 

it addresses, complex because of the need for research in disciplines as 

diverse as radioastronomy and molecular biology, and scientifically sound as 

measured by the continued excellence of its research product. 

The classic experiments of Miller and Urey, demonstrating the abiotic 

synthesis of essential biomolecules, were followed by a marked progression 

or evolution of research ideas that can be characterized as follows: precise 

identification of prebiotic simulation products; tests of the generality of 

conditions under which these syntheses occur; examination of extraterrestrial 

materials and environments for evidence of similar compounds and processes; 

adaptation of organisms to simulated extraterrestrial environments; the search 

for life in lunar samples, on Mars and beyond; and, probing the origin of 

biological structures, metabolic processes, and the genetic code. NASAsponsored research in this area has been highlighted by several key discoveries, including demonstration of abiotic origin of meteoritic biomolecules, expansion of the range of environmental extremes over which organisms could 

adapt, characterization of the unusual surface chemistry on Mars, determination 

of earliest microbiological phylogenetic relationships, and development of the 

role of clays in origin of essential biopolymers. 

Maintenance of a basic research program like this, in a mission-oriented 

agency where planetary missions to targets of exobiological significance are 

limited, is accomplished by focusing on the relationship between the origin 

of life on Earth and the origin and evolution of the solar system itself. 

2 
This relationship is explored in tasks dealing with theoretical and experimental modeling of outer planet atmospheric chemistry and implications for 

prebiotic syntheses, study of comets and meteorites as sources of preformed 

organic matter on primitive Earth, and determining mechanisms and thereby 

environments for abiotic production of biomolecules. The result is a program 

which is dependent on mission data for model validation, on the one hand, 

and which defines fundamental science objectives for planetary missions, on 

the other hand. 

Although other federal agencies also support specific research tasks 

relevant to the origin of life, NASA's Exobiology Program is unique in several 

respects. It emphasizes the relationship between the origin of life and 

the properties of the solar system; its scope is more comprehensive as it 

ranges from biogenic elements to the search for extraterrestrial life; and 

it maintains a strong in-house technical core around which an extensive extramural program has been fashioned. 

3 
PROGRAM 

Speakers are denoted with an asterisk. 

Monday Morning, August 2, 1982 

8:00 a.m. Registration, Foyer, N-201 

8:30 a.m. Welcome - Angelo Guastaferro, Deputy Director 

Ames Research Center 

8:35 a.m. Conference Logistics - John Billingham 

Ames Research Center 

8:40 a.m. Introduction - Donald DeVincenzi 

NASA Headquarters 

SESSION I - EXTRATERRESTRIAL CHEMISTRY 

Chairman: Sherwood Chang 

8:45 a.m. "Accurate Theoretical Predictions of the 

(P- 38) Rotational Constants of Candidate 

Interstellar Molecules" 

D. DeFrees*, D. McLean, and G. Loew 

9:05 a.m. 

(p. 39) 

"Plasma Discharge: Meteorite Organics 

Model" 

S. Chang, S. Gupta*, J. Lawless, 

R. Shipp, and T. Wydeven 

9:25 a.m. "13C NMR Spectroscopy of the Insoluble 

(P. 40) Carbon of Carbonaceous Chondrites" 

J. R. Cronin*, G. U. Yuen, 

S. Pizzarello, and J. S. Frye 

9:45 a.m. "Behavior and Recovery of Some Amino Acids 

(p. 41) From the Murchison Meteorite: Research in 

Progress" 

H. Ogino and B. Nagy* 

lo:05 a.m. Coffee 
lo:15 a.m. 

(p. 42) 

lo:35 a.m. 

(P. 43) 

lo:55 a.m. 

(P. 44) 

11:15 a.m. 

(P- 45) 

11:35 a.m. 

(p. 46) 

11:55 a.m. 

"Mars' Early Climate-- A Possible Habitat for 

Terrestrial Type Primitive Organisms" 

W. R. Kuhn* and S. E..Postawko 

"An Investigation of the Effects of Hot Atom 

Chemistry of Minor Constituents in the 

Atmospheres of Jupiter and Saturn" 

T. W. Scattergood* and S. Chang 

"Phosphine Photolysis. Applications to 

Jovian Atmospheric Chemistry" 

J. P. Ferris*, A. Bossard, and 

R. Benson 

"Photochemistry of Methane, Nitrogen and 

Carbon Monoxide on Titan--Abiotic Synthesis 

of Organic Compounds" 

Y. L. Yung*, M. Allen, J. P. Pinto, 

and E. P. Gardner 

"The Organic Clouds of Titan" 

C. Sagan* and B. N. Khare 

Lunch 

Monday Afternoon, August 2, 1982 

SESSION II - PRIMITIVE EARTH 

Chairman: James Lawless 

1:00 p.m. "Photochemistry of Methane in the Earth's 

(p. 48) Early Atmosphere" 

J. F. Kasting, K. J. Zahnle*, and 

J. C. G. Walker 

1:20 p.m. "Photochemical Reduction of Carbon Monoxide 

(p. 49) in the Earth's Primitive Atmosphere" 

A. Bar-Nun and S. Chang* 

5 
1:40 p.m. 

(PO 50) 

2:00 p.m. 

(p. 51) 

2:20 p.m. 

(p. 52) 

2:40 p.m. 

(p. 53) 

3:00 p.m. 

(p. 54) 

3:20 p.m. 

3:40 p.m. 

(P. 55) 

4:00 p.m. 

(p. 56) 

4:20 p.m. 

(PO 57) 

"The Atmosphere of the Primitive Earth and 

the Prebiotic Synthesis of Organic 

Compounds" 

S. L. Miller* and G. Schlesinger 

"Chemical Evolution and Model Photosynthetic 

Protocells" 

C. E. Folsome* 

"Clays and the Origin of Life" 

H. Hartman* 

"The Adsorption of Biomonomers onto 

Homoionic Clays" 

S. Bzik, F. Church, J. Lawless*, 

N. Levy, J. Mazzurco, and M. Mortland 

"Catalysis of Peptide Formation on Clay 

Surfaces by Polyribonucleotides and by Short 

Peptides" 

D. H. White* 

Coffee 

"Solvation/Desolvation Induced Luminescence 

in Kaolin --Indicator of Surface Reactivity?" 

L. M. Coyne* 

"Prebiotic Formation of Phosphoanhydrides, 

Like ATP, by Chemical Pathways that Resemble 

Fermentation (Glycolysis)" 

A. L. Weber* 

"Experiments on the Origin and Amplification 

of Molecular Chirality" 

W. A. Banner* 

6 
4:40 p.m. 

(pa 58) 

"Absorption of Biomolecules (5'-Nucleoside 

Monophosphatesand Amino Acids) onto 

Homoionic Clay Surfaces" 

J. B. Orenberg* 

5:00 p.m. Adjourn 

Tuesday Morning, August 3, 1982 

SESSION III - INFORMATION TRANSFER 

8:30 a.m. 

(Pa 60) 

8:50 a.m. 

(p. 61) 

9:lO a.m. 

(p. 62) 

9:30 a.m. 

(P- 63) 

9:50 a.m. 

(I?. 64) 

1O:lO a.m. 

lo:30 a.m. 

(p- 65) 

Chairman: Robert MacElroy 

"NMR Studies of Interaction Between Nucleic 

Acids & Proteins" 

C. Ponnamperuma and M. Hobish* 

"Cyanamide Mediated Prebiological Synthesis 

of Phospholipids, Oligopeptides and 

Oligonucleotides" 

J. Oro* 

"An RNA Polymerase Model" 

L. E. Orgel*, T. Inoue, and H. Fakhrai 

"Self-Ordering -+ Reverse Translation?" 

S. W. Fox*, T. Nakashima, and 

R. M. Syren 

"Possible Pathways Towards the Evolution of 

the Genetic Code" 

F. R. Eirich* and M. Paecht-Horowitz 

Coffee 

"The Chemical Basis for the Origin of the 

Genetic Code and the Process of Protein 

Synthesis" 

J. C. Lacey*, Jr. 

7 
lo:50 a.m. "Nucleic Acid Template Properties" 

(pa 66) R. Rein* and T. Kieber-Emmons 

11:lO a.m. "The Influence of Water on the Stability of 

(p. 67) DNA Base Pairs" 

A. Pohorille*, S. K. Burt, and 

R. D. MacElroy 

11:30 a.m. Lunch 

Tuesday Afternoon, August 3, 1982 

SESSION IV - SOLAR SYSTEM EXPLORATION 

12:30 p.m 

(p. 69) 

12:50 p.m 

(p. 70) 

1:lO p.m. 

(PO 71) 

1:30 p.m. 

(p. 72) 

Chairman: Glenn C. Carle 

"New GC Columns for Investigation of the 

Atmospheres of Titan and the Outer Planets" 

G. E. Pollock*, D. R. Kojiro, and 

F. H. Woeller 

"Limits of In Situ Detection of Volatiles in 

Solar SystemE-ration" 

F. H. Woeller*, D. R. Kojiro, and 

G. C. Carle 

"Analysis of Cometary Dust by Gas 

Chromatography" 

B. J. O'Hara* 

"Multiplex Chromatography for Solar System 

Exploration" 

J. R. Valentin*, G. C. Carle, and 

J. B. Phillips 
SESSION V - PLANETARY PROTECTION 

Chairman: Donald DeVincenzi 

1:50 p.m. 

(pm 74) 

"Proposed New Policy for Planetary 

Protection" 

D. L. DeVincenzi, P. D. Stabekis*, and 

J. B. Barengoltz 

2:lO p.m. Open Discussion 

2:50 p.m. Coffee 

SESSION VI - FUTURE DIRECTIONS 

Chairman: John Billingham 

3:lO p.m. 

(p. 76) 

"Biogenic Elements and Their Compounds: The 

Astrophysical Context" 

J. Wood* 

3:30 p.m. 

(Pm 77) 

"Galapagos Hydrothermal Vent Ecologies: 

Possibilities for Neoabiogenesis?" 

C. Ponnamperuma and M. Hobish* 

3:50 p.m. 

(p. 78) 

"Evolution of Complex and Higher Organisms" 

D. Raup* and J. Billingham 

4:lO p.m. 

(p. 79) 

"Role of Exobiological Science in the Future 

of Solar System Exploration" 

J. Oro* 

4:30 p.m. "Status of SET1 Research" 

(p. 80) F. D. Drake* 

4:50 p.m. Adjourn 

9 
7:00 p.m. Dinner 

Guest Speaker 

Wednesday Morning, August 4, 1982 

8:30 a.m. 

(Pa 82) 

8:50 a.m. 

(P. 83) 

9:lO a.m. 

(p. 84) 

9:30 a.m. 

(p. 85) 

9:50 a.m. 

(p. 86) 

1O:lO a.m. 

lo:25 a.m. 

(p. 87) 

SESSION VII - GEOLOGICAL RECORD 

Chairman: David Des Marais 

"Aspects of Evolution and Diversity of 

Precambrian Life: Archean and Proterozoic" 

E. S. Barghoorn* and P. K. Strother 

"Archaean Stromatolites from Zimbabwe: 

Evidence for Environmental Conditions" 

P. I. Abell*, J. McClory, E. Nisbet, 

and A. Martin 

"Geochemistry of Carbon in the Lower Crust 

and the History of the Carbon Cycle on 

Earth" 

D. Des Marais* 

"The Oxygen Isotopic Record in Precambrian 

Kerogens" 

J. M. Hayes and K. W. Wedeking* 

"Alteration Paths of Sedimentary Rock 

Organic Matter During Burial" 

I. R. Kaplan* 

Coffee 

"The Importance of Metal Complexed Amino 

Acids in Geochronology of Fossils and to the 

Origin of Chirality" 

G. G. Smith* 

10 
lo:45 a.m. "The Origin and Evolution of Microbial 

(p. 88) ' Endoliths" 

S. E. Campbell and S. Golubic* 

11:05 a.m. "Organic Chemical Gradients in Laminated 

(p- 89) 

Cyanobacterial Mats from Solar Lake, Israel" 

A. L. Burlingame* 

11:25 a.m. "Geochemical Anomalies Near the Cretaceous- 

(p. 90) Tertiary, Eocene-Oligocene and PermianTriassic Boundaries" 

F. Asaro*, L. W. Alvarez, W. Alvarez, 

and H. V. Michel 

11:45 a.m. Lunch 

Wednesday Afternoon, August 4, 1982 

SESSION VIII - EARLY BIOLOGICAL EVOLUTION 

1:00 p.m. 

(PO 92) 

1:20 p.m. 

(p. 93) 

1:40 p.m. 

(p. 94) 

2:00 p.m. 

(p. 95) 

Chairman: Lawrence Hochstein 

"Microbial Mats and Early Evolution" 

L. Margulis* and J. F. Stolz 

"Evolutionary Relationships in the 

Microbial World" 

G. E. Fox* and C. R. Woese 

"Molecular Evolution and Studies on 

Methanobacterium formicicum" ~- - 

J. Bush, R. Holmquist*, and T. Jukes 

"Determining the Origin and Early Evolution 

of Living Organisms Based on Protein and 

Nucleic Acid Sequence Data" 

M. 0. Dayhoff* 

11 
2:20 p.m. 

(P. 96) 

2:40 p.m. 

(p. 97) 

3:00 p.m. 

3:20 p.m. 

(p. 98) 

3:40 p.m. 

(P. 99) 

4:00 p.m. 

(p. 100) 

4:20 p.m. 

(PO 101) 

4:40 p.m. 

"A Low Molecular Weight, Archaebacterial 

Adenosine Triphosphatase" 

H. Kristjansson, C. Ponnamperuma, and 

L. Hochstein* 

"A Yeast-Like First Eukaryote?" 

H. S. Vishniac* and S. Baharaeen 

Coffee 

"Oxygen Requirements for Lipid Synthesis in 

Microorganisms" 

L. Jahnke*, C. Volkmann, and 

H. P. Klein 

"Primary and Secondary Energy Conversion in 

Halobacterium Membranes" 

J. K. Lanyi* and B. Schobert 

"Light Energy Conversion in Halobacteria" 

R. A. Bogomolni* and W. Stoeckenius 

"The Cryptoendolithic Microbial Community: 

A 'Closed' Ecosystem in Nature" 

E. I. Friedmann*, R. 0. Friedmann, 

L. Kappen, C. C. McKay, and 

J. R. Vestal 

Adjourn 

12 
SESSION SUMMARIES 

13 
Session I: Extraterrestrial Chemistry 

Chairman - Sherwood Chang 

Papers delivered in the session on "Extraterrestrial Chemistry" addressed 

diverse aspects of the chemistry of the biogenic elements (H, C, N, 0, P, S) 

that are related to interstellar clouds, the solar nebula, meteorites (and 

their parent bodies), Jupiter, and Saturn's satellite, Titan. Organic matter 

is known or inferred to exist in all these extraterrestrial environments. 

Attempts to elucidate its origins therein contribute to a general understanding of the processes involved in the chemical evolut ion of the solar system 

and the bodies within it. 

It is appropriate to view the first four papers from the perspective' 

that the organic matter observed in primitive solar system objects (like 

meteorites) may have components produced in interstellar clouds, the solar 

nebula, the parent body itself, and terrestrial environments. One major 

challenge is to sort out and identify these contributions. 

DeFrees, McLean, and Loew have carried out quantum mechanical calculations to determine the geometries of HCCOH, HOCN, HCNH+, and HOCO+, which 

are molecules predicted by ion-molecule reaction schemes to occur in interstellar clouds. The frequencies of rotational transitions calculated from the 

geometries serve as the bases for microwave searches for these species. It 

is noteworthy that HCNH+ is a key intermediate in the schemes for synthesis 

of HCN and other interstellar nitriles, and HOCO+ may be a precursor for 

interstellar COZ, whose geometry precludes microwave identification. 

Chang, Gupta, Lawless, Shipp, and Wydeven reported that the results of plasma 

discharge reactions in H2-CH4 mixtures designed to simulate reactions that 

may have occurred in the solar nebula and contributed to the organic com14 
pounds in meteorites.. They found that unstable intermediates formed at 115°K 

survived and continued to generate additional hydrocarbon products at room 

temperature. This observation suggested that reactive interstellar species 

condensed on grains during the low temperature (-20°K) isothermal stage of 

protostellar cloud collapse may have contributed to the chemistry of the 

solar nebula subsequently at higher temperatures. They also reported that 

synthesis of acetylenic compounds and preferential incorporation of 12C 

relative to 13C into products were favored by high abundances of H,. 

Cronin, Yuen, Pizzarello, and Frye used solid state '13C-NMR spectroscopy to show that the acid-insoluble carbon-rich matter composing the bulk 

of the carbon in carbonaceous meteorites may exist in two forms, at least. 

The Orgueil (CI), Murchison (CM), and Allende (CV3) meteorites contained 

a common component with a dehydrogenated, polycyclic aromatic network as a 

basic structural feature. Orgueil and Murchison contained an additional component having hydrogen-containing aliphatic and aromatic-olefinic structures. 

The origins of these major carbon-bearing phases remain obscure, however. 

Ogino and Nagy summarized a variety of control experiments carried out 

on a mixture of amino acids as a guide to determining their behavior and recovery during extraction from Murchison meteorite. Although these experiments 

were intended to place bounds on the contribution of terrestrial analytical 

procedures to the recently reported L-enantiometric excesses in Murchison 

amino acids, no firm conclusion regarding the origin of the excesses was 

drawn. 

The next four papers dealt with the chemistry of the Outer Planets, where 

reactions are now occurring that may have taken place during their earliest 

history. This possibility had led to the speculation that the chemistry of 

Titan provides a model for that of a hypothetical primitive Earth endowed with 

15 
a H~-CH'+;NZ atmosphere. 

Scattergood, Aronowitz, Flores, and Chang presented a quantitative 

assessment of the efficiency with which kinetically hot hydrogen atoms, 

produced by ammonia photolyses in the presence of large excesses of HP, can 

abstract a hydrogen atom from CHs, thereby producing a methyl radical. Their 

results now provide a basis for determining the extent to which hot hydrogen 

atom reactions can occur in hydrogen-rich as well as hydrogen-poor planetary 

atmospheres. In principle, these reactions can lead to organic synthesis in 

regions where the direct photolysis of methane cannot take place. 

Ferris, Bossard, and Benson have elucidated the photochemistry of phosphine in the context of Jupiter's atmosphere. Their experiments show that 

diphosphine (P2H4) is the initial photoproduct in the photolysis of either 

PH3 or NH3-PH3 mixtures. Apparently, diphosphine synthesis is independent 

of temperature above 175°K and uninfluenced by the presence of HP and N2. 

These results serve as the basis for Ferris et al.'s postulation that the 

aerosols observed above Jupiter's NH3 clouds may be composed of diphosphine. 

Yung, Allen, Pinto, and Gardner described their investigations of the 

reactions in Titan's atmosphere initiated by ultraviolet light and high-energy 

particle bombardment. Their approach centered on a one-dimensional computational model which took into account exospheric hydrogen escape, secondary 

methane photolysis, synthesis of higher hydrocarbons, production of aerosols, 

and coupling of the chemistries of C, N, H, O-bearing species. The results 

of the model calculations predicted molecular abundances of atmospheric species 

in accord with those revealed by Voyager observations. They also added credence 

to the often-expressed view that large amounts of organic compounds should be 

condensed on Titan's surface. 

Sagan and Khare pointed out that solid products, dubbed "tholins," 

16 
produced by exposure of CH, and N; to high-frequency electric discharge, 

are endowed with physical properties consistent with those of Titan's cloud 

components. Thus tholin particle size, refractive indices, and spectral 

reflectivity in the near UV and infrared wavelengths longward of 6 urn were 

judged to be consistent with Titan observations. Based on their chemical and 

spectroscopic characterization of the artificial tholins, Sagan and Khare 

inferred that Titan's clouds are composed, in part, at least, of organic heteropolymers containing polynitrile and hydrocarbon functional groups. 

17 
Session II: Primitive Earth 

Chairman - James Lawless 

This session dealt with the processes that occurred on the putative 

primitive Earth, from the photochemical behavior of atmospheric components 

to the interaction of protobiological monomers with mineral surfaces. 

The first paper, by Kasting, Zahnle, and Walker, discussed the numerical 

modeling of methane photochemistry in the anaerobic terrestria7 atmosphere. 

The model considers the photochemical production (and loss) of more than 20 

species and suggests that the concentration of CHI, will depend strongly upon 

the amount of COZ present. 

A second paper dealing with the photochemistry of the Earth's primitive 

atmosphere was presented by Bar-Nun and Chang. Gas mixtures containing HP0 

and CO with various proportions of HP, COZ, and Nz were experimentally subjected to UV light and to a simulated solar spectrum. The results suggested 

that even if the only form of carbon in the primordial atmosphere was CO, or 

CO and CO2 (with no molecular hydrogen present), a variety of organic molecules 

could be produced by gas-phase photochemistry. 

In a final paper considering the atmosphere of the primitive Earth, 

Miller and Schlesinger studied the synthesis of organic compounds in a spark 

discharge, using various mixtures of CHb, CO, COZ, Hz, H20, NP, and NH3. They 

showed that glycine is the major (only) amino acid produced from CO and CO2 

atmospheres, and, if the more complex amino acids are required, then their 

study shows a need for CHI, in the primitive atmosphere. 

In a series of studies by Folsome, aqueous suspensions of CaC03, formaldehyde, and hydrazine produced organic molecules when exposed to long 

wavelength UV light. He reported the presence of pyrimidines, amino acids, 

18 
deoxyribose, and 0rgani.c microstructures. This is the first report of such 

species occurring from a single photochemical reaction. 

Five papers dealt with the role of clays in the processes that could 

have led to the origin of life. Hartman discussed his new proposal in the 

area and summarized the role that iron-rich clays could have played in the 

fixation of CO2 and NZ into organic molecules. A paper by Bzik, Church, Lawless, Levy, Mazzurco, and Mortland discussed the ability of bentonite, 

homoionic in Zn, to concentrate nucleotides from dilute solution and selectively adsorb 5'AMP from a mixture which also contained the 2' and 3' isomers. 

A paper by Orenberg showed the effect of different metal ions on the adsorption of organic molecules onto homoionic clays. In general, it was observed 

that Trp was more strongly adsorbed than Phe on clays containing Mn2+, Fe3+, 

Co21t, Ni2+, or Zn2+. White reported the effect of other organics (polyribonucleotides and peptides) on the catalysis of peptide formation on clay 

surfaces. He reported, for example, that 2 nmoles of His-His promotes the 

formation of 100 nmoles of additional glycine peptides and suggests that HisHis acts as a catalyst in this process. In the final paper in the clay section, Coyne outlined the many-faceted role that clays could have played in the 

origin of life and reported on the blue to near-UV light released by the 

desolvation of a water-wet paste of kaolin. Studies are currently under way 

to correlate glycine oligomerization to this light emission. 

A paper by Weber discussed possible prebiotic formation of phosphoanhydrides (such as ATP) using thioesters. He showed that thioesters which 

are energy rich are able to bring about anhydride formation and produce species 

such as pyrophosphate in the presence of hydroxyapatite, a phosphate mineral. 

The final paper in this session was by Bonner and dealt with experiments 

on the origin and amplification of molecular chirality. Among the results 

19 
he reported was his recent finding that clays can protect amino acids against. 

racemization. 

20 
Session III: Information Transfer 

Chairman - Robert MacElroy 

The problems of information transfer in primordial 

systems range from fundamental questions about self-rep 

systems through the evaluation of models for the origin 

genetic code. 

and ear ly biotic 

lication in nonbiotic 

and evolution of the 

At a most fundamental level are questions about the formation of the 

prebiological molecules that constitute the basic elements of a coding system. 

J. Or6 discussed the role of cyanamide in condensing amino acids to oligopeptides, phosphatides to phospholipids, and nucleoside monophosphates to 

oligonucleotides. The fact that the yield of oligomers is increased in the 

presence of imidazole and arginine, he suggested, implies that a proton relay 

mechanism common to these compounds and to cyanamide, involving the (N=C-N-) 

group, may be operative. 

S. Fox, with T. Nakashima and R.M. Syren, reported that thermal proteinoids containing sufficient basic amino acids act to catalyze the formation 

of peptide bonds between all types of ami no acids in the presence of lysinerich proteinoids. The sequence compositi on of the product (the proportion 

of gly and phe incorporated into phe-gly vs. gly-phe) is influenced by the 

presence of polynucleotides and polynucleotide-proteinoid. He suggested that 

a variant of this system that catalyzes the formation of polynucleotides may 

be an example of a reverse translation process. 

A different approach to the formation of specific peptides has been 

taken by F. Eirich and M. Paecht-Horowitz, who reported on the role of clays 

in oligomer synthesis. They described the condensation of activated amino 

acids on clay surfaces and reported adsorption isotherms of amino acids and 

nucleotides. They also reported the effects on adsorption of preadsorbed 

21 
peptides, and of coadsorption of bases and nucleotides. They anticipate 

that their studies will illuminate the interactions on clay surfaces that 

lead to specific condensation products. 

The transfer of information in the form of sequence-specific templating 

in the absence of enzymes has been approached experimentally by L. Orgel. 

Orgel, with T. Inoue and H. Fakhrai, reported further studies on an RNA 

polymerase model in which polycytidylic acid, acting as a template, is capable of generating a variety of polyguanidilic acid polymers, up to a length 

of 40 nucleotides with high fidelity. These studies have been extended to 

include the synthesis of mixed oligomers containing an excess of G directed 

by an oligomer containing an excess of C. Bases whose complements were absent from the template were not incorporated into the product oligomers. 

The molecular basis of the function of Orgel's model has been examined 

using theoretical model approaches. R. Rein, with T. Ki'eber-Emmons, reported on an exploration of why polypyrimidines are effective templates for 

polynucleotide synthesis, while polypurines are not. Their results suggest 

that template efficiency is the consequence of a subtle interplay between 

conformational stabilities and helix compatibilities. By calculating binding isotherms for incoming nucleotides and the template polynucleotide strand, 

they were able to calculate the probabilities of chain elongation, thus providing an explanation for the sequence length distribution that is experimentally observed by Orgel and co-workers. Rein also described recent work 

on the interaction of specific peptides with nucleotide sequences (the lac 

system). 

A major conundrum in studies of the origin of life is the relationship 

between the genetic code (a sequence of nucleotides) and the amino acids 

that the code specifies. Two papers addressed this problem. The first, 

22 
presented by M. Hobish, with C. Ponnamperuma and B. Cherayil, described NMR 

studies of interactions between nucleic acids and proteins. The resul.ts 

presented suggest that Mg ions affect the protons of 5'AMP interacting with 

phenylalanine methyl ester, causing a downfield shift in ring proton signal, 

and that the amino acid binds more strongly to 5'AMP (an anticodon monomer) 

than to 5'UMP (a codon monomer). 

A very similar observation was made by J. Lacey, who reported binding 

constants of phenylalanine to AMP, GMP, CMP, and UMP of 6.6, 3.5, 2.1, and 

1.1 M-l, respectively. Lacey extrapolated from these observations of affinity to suggest that they may provide the reason that the only anticodons 

of phenylalanine contain AAPu (3'>5'). He suggests that the reaction rates 

of hydrophobic amino acids with ATP are correlated with the affinities of 

these amino acids (phe, leu, ile, val, met) for ATP, and that a general 

principle can be postulated: that the rates of various chemical reactions 

between amino acids and nucleotides are a function of the affinity between 

the reacting species. An extension of this principle is that the genetic 

code arose as a consequence of selective affinities between amino acids and 

their anticodonic nucleotides. 

Affinities and interactions between molecules are highly dependent upon 

the solvent in which they occur. A. Pohorille, with S.K. Burt and R. MacElroy, 

reported on model studies of solvent interaction with nucleic acid bases. 

The approach used was Monte Carlo simulation of solvent-solute geometries, 

which allows the calculation of system geometry and energy at equilibrium. 

The results were used to explain experimental observations that, in hydrophobic environments (using nonpolar solvents) an A-U (hydrogen bonded) pair is 

favored over an A/U (stacked) pair by 8 kcal/mole, while in a polar solvent 

(water) A-U is favored. By extension, such data can be used to explain that 

23 
phenomena such as nucleic acid stability are not due to hydrogen bonding 

but rather to an effect of the solvent. 

24 
Session IV: Solar System Exploration 

Chairman - Glenn Carle 

The session on Solar System Exploration was devoted to reports on 

current research studies in analytical concepts of gas chromatography. These 

studies were focused on application of the techniques to current and future 

opportunities to conduct analyses of extraterrestrial samples, where data 

would be acquired specifically to support exobiology science goals and objectives. Examples of candidate environments suggested in this session's 

reports included interplanetary dust or "Brownlee particles," outer planets 

and their moons, Mars, comets, and asteroids. The emphasis was placed on 

volatile compounds of the biogenic elements which might be found in the 

atmospheres or solid materials of these bodies. 

Current state-of-the-art flight instruments, for example, Pioneer Venus 

Gas Chromatograph, which have been used in the past to make these measurements, 

have sensitivity limits of about 1 ppm for these chemical species. Further, 

no flight instrumentation is currently available to analyze volatiles included 

in solid phase materials. The reports at this session made it clear that the 

state-of-the-art has been advanced sufficiently so that these limitations, 

particularly sensitivity, will not apply to future flight instruments. 

Fritz Woeller reported on his work with miniature metastable ionization 

detectors. He has developed a gas chromatograph detector which weighs approximately 1 gram and which universally detects down to 1 ppb levels of gaseous 

components in model planetary atmospheres. He showed comparison sensitivity 

data with current mass spectrometers, demonstrating that his detector has 

equal or better sensitivity. This detector does, however, require columns 

that are unusually stable and free from bleed, such as porous polymers and 

molecular sieves. 

25 
New types of column materials are now being prepared that are compatible with his detector and will expand its application to other than fixed 

gases. Glenn Pollock reported on reacted-in-place phases, such as substituted urethanes, which are bound directly to porous silica. Using these 

phases, he has produced miniature columns (1 mm I.D. x 75 cm long) which 

separate most low molecular weight hydrocarbons at room temperature in less 

than 3 minutes. These columns are fully compatible with the metastable 

ionization detector and are usable in quantitative analysis down to a few 

ppb. 

Application of the new detector and column technologies to prototype 

instruments which would be useful in making flight measurements specific to 

exobiology goals has also progressed. Bonnie O'Hara reported on her instrumentation work in which she combined the metastable ionization detector with 

flight-type columns to study the volatiles that might be evolved from "Brownlee 

particles." Using Murray meteorite as a source of model particles, she was 

able to demonstrate the ability to analyze thermally evolved volatiles at the 

100 ppm level in single 10 pm-sized particles. She plans to analyze "Brownlee 

particles" and report findings as samples become available in the laboratory. 

The last report of the session was made by Jose' Valentin on multiplex 

gas chromatography as an entirely new technique for analysis of planetary 

atmospheres. In this technique, many samples are rapidly admitted to a column 

without regard to elution time, followed by detection in the conventional 

manner. The signal is then subjected to mathematical deconvolution using, 

for example, Fourier transforms. He was able to demonstrate the usefulness 

of the technique in analyzing complex mixtures while producing an effective 

increase in sensitivity of loo-fold, that is, 100 ppb sensitivity using a 

commercial thermal conductivity detector. 

26 
Session V: Planetary Protection 

Chairman - Donald DeVincenzi 

The proposed new U.S. Planetary Protection Policy was presented in this 

session. This simplified and less stringent new policy proposes: deemphasizing the use of mathematical models and quantitative analyses; establishing 

requirements for target planet/mission type (i.e., orbiter, lander, etc.) 

combinations; considering sample return missions a separate category; simplifying documentation; and imposing implementing procedures (i.e., trajectory 

biasing, cleanroom assembly, spacecraft sterilization, etc.) by exception if 

the planet/mission combination warrants such controls. 

27 
Session VI: Future Directions 

Chairman - John Billingham 

The session on Future Directions began with a review by John A. Wood 

of a recent scientific workshop which examined the major scientific questions 

and research opportunities pertaining to the cosmic history of the biogenic 

elements (C, H, 0, N, P, S) and their compounds. Most exobiological research 

in the past has begun with the evolution of organic molecules on the Earth, 

but the raw materials for those molecules have a long and complex preplanetary 

history. Wood summarized some of the findings of the group, which 

dealt with stellar nucleosynthesis, supernovae, stellar winds, the interaction 

of gas and dust in the interstellar medium with all types of radiation, gravitational collapses of interstellar matter, solar nebulae, the aggregation 

of planetesimals, and today's partial remnants of those early processes, the 

comets and meteorites of the solar system. 

Mitchell Hobish next reviewed the recent discoveries of the deep sea 

hydrothermal vents in an ocean ridge near the Galapagos Islands. The chemistry, biology, and geology of these vents were the subject of a recent conference on the subject, organized by the University of Maryland. Hot water, 

laden with a wide variety of chemical species, pours out from the vents at 

temperatures which may reach over 300°C. Immediately around the vents is a 

complex and unusual ecosystem of microorganisms, shrimps, crabs, and strange 

large worms with no digestive system, all in total darkness. It is thought 

that the energy source for maintaining the system is chemoautotrophic, 

possibly sulfur bacteria. Hobish raised the question of whether the deep 

sea vents are an opportunity for investigating the concept of neoabiogenesis, 

as opposed to the conventional wisdom that once life is firmly established 

28 
on a planet it will prevent any later repetition of the origin of life process. 

David Raup next summarized a series of three NASA interdisciplinary 

science workshops on the evolution of complex life (i.e., beyond the Precambrian Era). The group developed many research topics that need to be addressed on the relationship of astrophysical or solar system events to the 

evolution of complex life, on Earth or elsewhere. Raup showed an interesting 

curve depicting the progressive increase in the number of species during the 

Phanerozoic, punctuated by several major declines whose cause is still not 

completely understood (although the asteroid impact theory of Alvarez et al. 

has suggested one possible explanation). The central question is whether 

such extinctions accelerate, retard, or have no real influence on the longterm evolution of complexity, to which there does seem to be a trend. (It 

is of interest to note that all these considerations apply to Precambrian 

biology as well.) 

John Or6 next gave a talk on the role of exobiological science in the 

future of solar system exploration, as studied by another series of NASA 

science workshops held over the past year. The participants identified three 

major questions to be addressed: (1) What can the study of extraterrestrial 

organic chemistry tell us about the prebiological chemical era on Earth and 

elsewhere? (2) How did the formation and earliest history of the Earth set 

the stage for chemical and early biological evolution? (3) Once life has 

emerged, what is the impact of the evolution of life on the Earth's planetary 

evolution? The primary targets identified for solar system exploration, to 

help answer some of these questions, are: (1) small primitive bodies, 

comets, asteroids, meteorites, and interplanetary dust; (2) giant planets 

and their satellites, with special emphasis on Titan and Europa; and (3) 

terrestrial planets and their satellites, essentially Mars, Phobos, Deimos, 

29 
Venus, and the Moon. 

The final paper was given by Frank Drake, who discussed the status 

of research on the Search for Extraterrestrial Intelligence (SETI). Detailed 

studies of the best way to carry out the search for extraterrestrial life 

have reconfirmed the idea that the most promising approach to the detection 

of other civilizations is to search for radio transmissions over a large 

part of the microwave spectrum, using fine resolution and examining millions 

of separate channels simultaneously. Such a "multichannel spectrum analyzer" 

would be used with existing large radio telescopes to look specifically at 

good target stars and also to carry out a sky survey to make sure that some 

unexpectedly strong signal is not being missed. Drake made some comments 

about searches elsewhere, particularly in the Soviet Union, where a number 

of large SET1 programs are under way. He concluded with two fundamental 

points: (1) that the current approach is very conservative; it does not 

demand a science and technology on the part of the other civilization that 

is beyond our own; and (2) that the only sensible way to proceed is to carry 

out a search. It is probably the only way to achieve a detection in the 

near future, and hence to resolve the usual debates about probabilities for 

the existence of extraterrestrial life. 

30 
Session VII: Geological Record 

Chairman - David Des Marais 

This session examined the evidence for biological evolution as it is 

recorded in ancient rocks. The speakers discussed not only fossil studies but 

also the preservation of biochemical fossils, the evidence for ancient climates, 

and the evolution of volatile element chemistry on Earth. 

Paul Abel1 presented chemical analyses of stromatolites in the Cheshire 

and Manjeri formations (2.7 b.y. old) of Zimbabwe. Abell, McClory, Nisbet, 

and Martin had noted that the primary sedimentary structures of these rocks 

were exceptionally well-preserved, and their carbonates were therefore well 

suited for the examination of Fe, Mg, Mn, Sr, and Rb abundances, as well as 

61e0 and 613C . The authors noted a cyclic variation in the mineralogy of the 

stromatolitic layers but were unable to find any correlative cyclic variations 

in the above chemical and isotopic parameters. The 6180 in the carbonates 

ranges from -9 to -13; the 613C of the carbonate and organic matter ranges 

from -0.5 to +0.4 and from -30.2 to -34.7, respectively. 

David Des Marais showed that the 613C of the carbon indigenous to midoceanic basaltic glasses is very close to -6 in samples from the Mid-Atlantic 

Ridge, the East Pacific Rise, and Hawaii. This value is very similar to the 

one obtained by mass averaging all the carbon in sediments. Such similarity 

indicates that the average carbon isotopic composition of the Earth's sedimentary reservoir has been remarkably constant over geologic time. Des 

Marais also presented evidence, from a collaboration with A. Truesdell, that 

most, if not all, of the hydrocarbons produced from continental geothermal 

systems derive from thermal decomposition of organic matter in the subsurface. 

Kim Wedeking discussed his new procedure, developed with J.M. Hayes, for 

31 
6180 analysis of recent and ancient organic matter. The Indiana group has 

analyzed recent material from Antarctica, from a Florida lake, and from the 

ocean sediments of Tanner Basin (California) and Walvis Bay (SW Africa). They 

notice a good correlation between the 6l*O of the organic matter and the 6l*O 

of the environmental water. Examination of organic matter with depth in the 

Green River and Paris Basins reveals that 6l*O varies with the hydrogen 

content. 

I.R. Kaplan reviewed his laboratory's recent findings concerning the 

diagenesis of organic matter. He first summarized the changes observed in 

elemental abundances, color, and chemical structure of the kerogen and its 

products. He then discussed his recent observations that clays such as kaolinite, illite, and montmorillonite can strongly influence both the relative 

production rates of methane and carbon dioxide and also the stable carbon 

isotopic composition of these diagenetic products. 

G.G. Smith discussed the processes that influence amino acid racemization. 

He investigated how moisture increases the rate of racemization in a fossil 

hominid skull from La Caune Cave, France. He also studied the effects of metal complexation upon racemization using different cations (Co, Ni, Pd) and 

complex configurations (cis versus trans isomers). The racemization rates were 

highest for cobalt and palladium complexes, intermediate for free amino acids, 

and lowest for nickel complexes. 

S. Golubic related details of his and S. Campbell's discovery of microbial endolith borings in the Eleonore Bay Formation (0.57 to 0.7 b.y. old), 

eastern Greenland. He discussed the structural details of these borings and 

how they are identified as being indigenous primary structures. He also presented observations from the Shark Bay stromatolites and discussed their 

significance regarding the destruction of potential stromatolites during the 

32 
Precambrian. 

A.L. Burlingame sumarized the history and significance of organic 

molecules which can be preserved in rocks to become biological markers 

("biomarkers") of past life. His analyses of the Solar Lake (Sinai) microbial mat indicated how the mat can serve as a model for the synthesis and 

preservation of biomarkers in the natural environment. His pyrolysis GC-MS 

data illustrate that the cyanobacterial sheath material persists with depth 

in the mat whereas the abundances of the fatty acids, isoprenoids, and low 

molecular weight acids are substantially modified and removed. 

F. Asaro, speaking for the L.W. Alvarez, W. Alvarez, and H. Michel group, 

discussed recently obtained chemical evidence for relationships between terrestrial asteroid impacts and biological extinctions. He reviewed the group's 

evidence for anomalously high Ir contents in samples obtained worldwide from the 

Cretaceous-Tertiary geologic time boundary. The elements platinum and gold 

are also anomalously high in these samples, as might be expected from the impact of a carbonaceous chondrite meteorite. This group is searching for 

elemental anomalies in rocks from other extinction episodes. They have found 

no anomalies at the Permo-Triassic time boundary; but may have identified an 

Ir anomaly at the Eocene-Oligocene boundary. 

33 
Session VIII: Early Biological Evolution 

Chairman - Lawrence Hochstein 

The 10 papers comprising this session covered three seemingly disparate 

topics: the phylogeny of microorganisms, putative models of early metabolic 

processes, and ecological models of primitive life. The unifying theme connecting these topics was the notion that contemporary organisms represent a 

fossil record within which resides evidence of the origin(s) and evolution 

of life. 

The paper by Fox and Woese summarized their studies using 16s and 5S 

rRNAs. The data obtained with the shorter ribosomal RNA confirmed the 

earlier proposition that the Archaebacteria represent a collection of organisms so unique that their separation from other prokaryotes can be warranted. The results also suggested that anaerobic organisms preceded aerobic 

ones and that the photosynthetic genotype was an ancient one. 

Bush, Holmquist, and Jukes described their test of the archaebacterial 

hypothesis by examining the aminoacyl tRNA synthetases from Methanobacterium 

formicicum. They proposed to establish a methanogen gene pool in an Escherichia coli host and to clone the appropriate aminoacyl transferase gene for -- 

sequence analysis and comparative acylation studies of tRNA from E. coli. -- 

Dayhoff described phylogenetic trees constructed utilizing a variety 

of evolutionary probes. The resulting schemes provided a horizontal phylogenetic picture with much internal consistency and in good agreement with 

relationships suggested by others. 5S rRNA sequences were found to be consistent with the endosymbiotic hypothesis and indicated that the chloroplasts 

of higher plants were derived from Anacystis and Prochloron-like organisms, 

that mitochondria arose from a purple sulfur-like bacterium, and that the 

cytoplasmic constituents had their origins from an archaebacterial line re34 
lated to Thermoplasma acidophilum or Sulfolobulus acidocaldarius. 

The phylogeny of a variety of yeasts obtained from the dry valleys of 

the Antarctic was described by Vishniac and Baharaeen via a hybridization 

technique using 25s rRNA which they have developed. 

Bogomolni and Stoeckenius described their studies with bacteriorhodopsin, 

which functions as a light-transducing proton pump. A variety of techniques 

have allowed them to define the photochemical cycle and the nature of the 

chromophore-binding site, and to identify a tyrosine moiety as being involved 

in the proton cycle. Lanyi and Schobert reported on a photochemical pigment, 

halorhodopsin, which at one time was thought to be a sodium pump. The evidence now indicates that this pigment functions as a chloride pump. Halorhodopsin in conjunction with a proton pump (bacteriorhodopsin) and a sodium/ 

proton antiporter establish the sodium/potassium gradients characteristic 

of extreme halophiles while maintaining constant cell volume. Both papers 

made a strong case for using the light-transducing pigments of the Halobacteria __---- 

as models of primitive energy transduction. 

The presentation by Kristjansson, Ponnamperuma, and Hochstein dealt 

with the energy-transducing ATP-ase from Halobacterium saccharovorum. ---___-- They 

pointed out that the notion of the ubiquitous distribution of the ATP-ases, 

which suggests that they arose early during evolution, was inconsistent with 

their complexity. A search for a simpler enzyme in the halobacter resulted 

in the characterization of an F1 subunit with an unusually low molecular 

weight. The possibility that the halobacter group may provide a fertile 

arena within which to investigate the evolution of cellular processes should 

not be overlooked. 

The studies of Jahnke, Volkmann, and Klein on the levels of ox.ygen necessary to sustain aerobic reactions involved in lipid metabolism in the 

35 
eukaryote Saccharomyces cerevisiae confirm their earlier observations that 

the levels of oxygen required are consistent with the levels that might have 

been present during the early transitions from an anaerobic to an aerobic 

atmosphere. These observations imply that eukaryotes could have arisen 

far earlier than previously thought. 

Margulis and Stolz described their studies of the microbial mats in 

a saline laguna in Baja California. The possibility that these mats represent models of the creatures that gave rise to the Precambrian stromatolites 

was suggested. Friedmann and his coworkers described their recent work on 

Antarctic organisms inhabiting rocks. This endolithic environment consists 

of primary producers, consumers, and decomposers. The authors suggest that 

a study of such ecosystems may provide a clue to how early life was established on the primitive Earth. 

The overall impression of this session was that extant organisms possess 

a tremendous storehouse of information from which the early origin(s) and 

evolution of life may be deduced. 

36 
SESSION I 

EXTRATERRESTRIAL CHEMISTRY 

37 
Accurate Theoretical Predictions of the Rotational 

Constants of Candidate Interstellar Molecules 

Doug DeFrees*, Doug McLean, and Gilda Loew 

Molecular Research Institute 

Palo Alto, California 94304 

In current theories, our solar system was formed 5 billion years ago by the 

gravitational collapse of a large cloud of dust and gas, the solar nebula. We 

have, of course, no direct evidence to support this idea. Indirect evidence 

lies in the nearby heavens where newly formed stars, and by implication solar 

systems, are observed to be imbedded in clouds of interstellar matter. An 

important question is what are these clouds of dust and gas made of? Any model 

for the formation of the earth and for the evolution of life upon its surface 

must be consistent not only with extrapolations of current conditions back into 

time but also with extrapolations made forward in time starting with the interstellar building blocks from which the sun, the planets, and other bodies in 

the solar system are thought to have formed. While we can't study the solar 

nebula, we can study other nebula believed to be possible star-precursors in 

the galaxy. An understanding of the composition and chemistry of galactic 

molecular clouds is necessary in order to understand the chemical evolution of 

solar system bodies which eventually led to the origin of life. 

More than 50 molecules have been identified in interstellar space by, for most, 

comparing microwave emission frequencies obtained with radio telescopes to 

laboratory microwave spectra of known compounds. In several cases the laboratory studies were done after the astronomical observation had been made and 

a tentative identification made on theoretical grounds. Some molecules, ions 

and free radicals for example, are stable under interstellar conditions but 

unstable under terrestrial conditions and thus extraordinary means are needed 

to obtain laboratory spectra. Of the over 200 unidentified lines known to 

radio astronomers it is probable that some arise from such unstable molecules. 

Quantum mechanical calculations of a molecule's geometry can lead to a prediction 

of its microwave spectrum, which, of sufficient accuracy, can be used to assign 

unidentified radio lines. We have been able to obtain accuracies on the order 

of ?0.3%. by the use of sophisticated molecular orbital theories and an empirical 

correction scheme. While this is not accurate enough to provide the definitive 

identification of new interstellar molecular species it can play an important 

role in guiding radio astronomical and laboratory searches as well as providing 

important corroborative evidence. We have made pred$ctions of the microwave+ 

specfra of the candidate interstellar molecules HCNH , HCCOH, HOCN, and HOC0 . 

HOC0 has tenatively been identified b$sed, in part, upon the results of+our 

calculations. Radio searches for HCNH and additional searches for HOC0 will 

be carried out in early July using the computed spectra as basis. 

38 
- 

PLASMA DISCHARGE: METEORITE ORGANICS MODEL 

S. Chang, S. GuptafC J. Lawless, R. Shipp and T. Wydeven 

NASA-Ames Research Center 

Moffett Field, CA 94035 

In spite of the extensive efforts, the processes that led to the organics in 

meteorites remains poorly understood. Recent results on isotopic differences 

for C, H, and N between the solvent soluble and acid insoluble fractions of 

various meteorites clearly suggest a spatial and a temporal inhomogeneity in 

the formation and introduction of these materials into the parent bodies. 

To gain insight into possible mechanisms responsible for these complex species 

in meteorites, we are currently exploring organic synthesis in a plasma 

discharge. Studies on the synthesis of organic molecules in heteorogeneous, 

non-equilibrium dynamic conditions (hydrogen rich, methane plasma discharge) 

have shown the production of linear and branched, saturated and unsaturated 

hydrocarbons. Trapping the products in liquid nitrogen and, subsequently, 

allowing them to warm to room temperature while monitoring their composition 

(l-24 hours) shows the formation of additional products indicating the presence 

of chemically reactive intermediates. 

13C isotopic data will be presented. 

The possible reaction mechanisms and 

The relationship of this work to other 

studies of laboratory simulated cosmochemicai environments will be discussed. 

39 
13C NMR SPECTROSCOPY OF THE INSOLUBLE CARBON 

OF CARBONACEOUS CHONDRITES 

John R. Cronint George U. Yuen, and Sandra Pizzarello 

Arizona State University 

Tempe, AZ 85287 

James S. Frye 

Colorado State University 

Fort Collins, CO 80523 

A record of chemical evolution has been uniquely preserved in 

carbonaceous chondrites in the form of a diverse suite of indigenous organic compounds. Although many compounds common to 

terrestial life are found in these meteorites, the composite lacks 

the selectivity expected of biotic products. Thus meteorites appear 

to bear witness to an episode of organic chemical synthesis predating or occurring early in the history of the solar system. 

The carbonaceous matter in these meteorites can be divided into 

soluble and insoluble fractions. Although the insoluble carbonaceous 

matter may account for from 70 to essentially 100 percent of the 

total carbon, the chemical structure of this material is not well 

unders od. In order to better characterize this material, solidstate 5s C NMR techniques have been applied to the insoluble residue 

obtained after HF-HCl digestion of three 

Cross polarization magic-angle spinning 15 arbonaceous chondrites. C NMR spectra were obtained of the insoluble carbon of the Orgueil (CI), Murchison 

(CM21, and Allende (CV3) meteorites. The Murchison and Orgueil residues give spectra similar to terrestrial coals and oil shales with 

two major features attributed respectively to carbon in aliphatic 

(sp3) and aromatic/olefinic (sp2) structures. The spectrum of the 

Allende insoluble carbon does not show these features. Without 

cross polarization all three meteorite digests give spectra with a 

single feature at 150 ppm. These results are consistent with a 

dehydrogenated polycyclic aromatic network as a basic structural 

feature of the insoluble carbon of all three meteorites. The CI 

and CM2 meteorites have, in addition, structurally diverse, hydrogen-containing aliphatic and aromatic/olefinic structures. 

40 
BEHAVIOR AND RECOVERY Oi SOME AMINO ACIDS FROM THE MURCHISON 

METEORITE: RESEARCH IN PROGRESS 

Hiroshi Ogino and Bartholomew Nagy* 

Laboratory of Organic Geochemistry 

Department of Geosciences 

The University of Arizona, Tucson, AZ 85721 

Detailed understanding of the nature of amino acids in carbonaceous chondrites, 

and their potential alterations during their extraction from these meteorites, 

probably will elucidate some of the more fundamental aspects of chemical evolution, 

with hope of shedding light on the evolution of life on Earth. The reason for this 

is that amino acids in carbonaceous chondrites may represent a relati‘vely advanced 

stage in chemical evolution, unaltered by recycled biological overprints as one may 

envision for chemical processes on Earth. This chemical evolutionary significance 

is valid only if terrestrial contaminations can be subtracted from indigenous moieties, 

which, as is known, is a considerably difficult task. 

The nature and the quantitative and qualitative recovery of amino acids from a stone 

of the Murchison meteorite is studied by a series of experiments in this laboratory. 

(1) A mixture of phenylalanine, tyrosine, methionine, glutamic acid, serine and isovaline were prepared and derivatized to N-PFP-, 0-acetyl-(+)-2-butyl esters for gas 

chromatography. The major loss of these amino acids occurred during the 6N HCl hydrolysis and cation exchange steps; amino acid concentrations, and the volume of NH40H 

used to elute the amino acids from the cation exchange column affected the recovery. 

(2) The decomposition of serine obeyed reversible first order kinetics in Hz0 with 

phosphate buffer, pH=6.9; (activation energy: 24.60 kcal/mole; frequency factor, 

In A(yr-l): 33.0) and in Hz0 with admixed meteorite (10.60 kcal/mole; In A (yr'l): 

19.4). In a similar kinetic experiment, designed to simulate initial terrestrial 

contamination and subsequent storage, serine in the absence of Hz0 and in air (18.40 

kcal/mole; In A(yr'l):26.7) showed that the extent of decomposition, under these 

conditions, at 25'C during 11 years is quite limited. (3) Notable quantities of 

alanine and a-amino-n-butyric acid were synthesized from serine and threonine, respectively, in the presence of Hz0 and meteorite powder at 15O'C. (4) L-aspartic acid 

became notably racemized when it was added to, and heated with, Murchison meteorite 

powder and H,O at llO°C or 105'C for 20 hrs in an attempt to evaluate whether certain 

extraction procedures may racemize amino acids. The concentration of the added L-aspartic acid was in large excess compared to the indigenous meteorite aspartic acid. 

The meteorite sample to water ratios and probably also the ratios of L-aspartic acid 

to sample and water seem to affect the extent of racemization. 25 mg Meteorite powder 

heated with 0.05 ml Hz0 at 105'C for 20 hrs indicated a pH of 28.5. The value of 

(D/L)t=2Ohrs- (D/L)+Oof L-aspartic acid heated in Hz0 at 105'C was closely similar 

to the same value calculated from data reported in the literature from another laboratory, i.e. 0.0143 vs. 0.0142, respectively. 

41 
l+QU'S' EARLY CLIMATE - A POSSIBLE HABITAT FOR 

TERRESTRIAL TYPE PRIMITIVE ORGANISMS 

William R. Kuhn*and Susan E. Postawko 

The University of Michigan 

Ann Arbor, Michigan 48109 

Of all the other planets in the solar system, Mars is the most likely 

to have supported some form of life. While today Mars' atmosphere is tenuous 

and the surface is cold, dry and bombarded with lethal ultraviolet radiation, 

conditions may have been much different in the past. Recent estimates indicate 

that one to three bars of CO2 may have been outgassed and could have resided 

in the atmosphere prior to being bound in the regolith. The many channels 

and valleys also provide ample evidence that water flowed on the surface and 

thus would have been present in the atmosphere certainly in larger concentrations than we find today. 

Could these larger amounts of CO2 have provided the necessary warming 

(greenhouse effect) to maintain temperatures above freezing over portions 

of the planet even though the solar constant was smaller? While modeling 

studies can never demonstrate that Mars at some time in the past contained 

terrestrial life forms, nevertheless if it can be shown that physical conditions 

on the planet yield climate spaces compatible with terrestrial organisms, then 

these studies would motivate and focus further planetary exploration which 

could help us to understand the evolution of life on our own planet. 

The latitudinal distribution of surface temperature has been calculated 

from a simplified thermodynamic energy equation that includes radiation (solar 

and longwave), potential energy, sensible, latent, convective heat, and allowing 

for mean meridional and eddy transport. The major input parameters are 

obliquity, solar radiation, and atmospheric carbon dioxide. 

For present-day Martian conditions (albedo, solar radiation and CO2), 

the model calculation gives results that agree with measured values; the 

mean surface temperature is 218k and polar cap temperatu.res are within a 

few degrees of the condensation temperature. The atmosphere is not capable 

of supporting 1 bar of CO2 alone. A large temperature increase does not 

occur when the CO2 increases to 1 bar since even with present day CO2 the 

major bands are nearly saturated. Polar temperatures are well below the 

CO2 deposition temperature and even near the equator the temperature has 

not reached 273K. With a 25% reduction in solar radiation the polar and 

equatorial temperatures are 155K and 220K respectively. 

The greenhouse effect due to different amounts of water vapor will be 

discussed as well as the ultraviolet radiation reaching the surface. 

42 
AN INVESTIGATION OF THE EFFECTS OF HOT ATOM CHEMISTRY OF MINOR 

CONSTITUENTS IN THE ATMOSPHERES OF JUPITER AND SATURN 

Thomas W. Scattergood* and Sherwood Chang 

NASA &es Research Center 

Moffett Field, CA 94035 

*SUNY at Stony Brook 

Stony Brook, NY 11794 

Studies of the atmospheres of the outer planets by both ground based telescopes 

and by space borne probes have shown these atmospheres to be complex mixtures 

of gases and aerosols. In addition to hydrogen, helium, methane and ammonia, 

all of which are expected to be present on the basis of thermodynamic cooling 

of the primordial solar nebula, ethane, acetylene and phosphine have heen 

detected on Jupiter and Saturn. These molecules, along with the swirling 

colored clouds, are indicators of active disequilibrium processes (chemistry). 

In the upper atmospheres photolysis and particle bombardment of methane can 

account for the presence of ethane and acetylene. In the vicinity of the white 

ammonia cirrus clouds where phosphine exists, the methane is shielded from 

photolysis by the overlying atmosphere. Photolysis of ammonia yields only 

colorless hydrogen and nitrogen. Thus another process for the coupling of 

carbon with nitrogen or phosphorus to form organic molecules in this reeion 

is required. One possible pathway is provided by the production of methyl 

radicals from the reaction of hot hydrogen atoms (from photolysis of ammonia) 

with methane. These radicals can then react with each other and with methane 

and ammonia to form more complex organic compounds. Since planetary processes 

that prevailed soon after the origin of the solar system may be occurring now, 

knowledge of chemical processes operating in various planetary atmospheres 

should provide important data for correlating the relationship between chemical 

evolution and planetary evolution in the solar system. 

For the study of hot hydroeen atom initiated synthesis of organic compounds in 

planetary atmospheres, a technique for the low level monitoring of the reaction 

of hot H with methane (H* + CH j CH + H ) using CD 

product HD by stable isotope m&s spe2tromet?y was 4 

and analysis of the 

deve oped. Using this 

method a suite of experiments on the 1849w photolysis of mixtures of hydrogen, 

ammonia and deuterated methane (representing model Jovian atmospheres) were 

carried out. For three ratios of CD4 / NH 

the hydrogen pressure was varied stepwise 4 

of 10/4, 20/4 and 40/4 (in mm Hg) 

rom 0 to 800 mmHg to study the effects 

of hydrogen on the process. Preliminary analysis of the experimental results 

indicates that although the efficiency of the hot atom abstraction process is 

low, ranging from 0.5 - 5% depending on the mixture composition, hot hydrogen 

atoms from the photolysis of ammonia can decompose co-existing methane in the 

presence of hydrogen. Also the diminution of the yield of HD with added H2 

was less than expected based on thermalization of the hot H by 'elastic' 

collisions with H 

results support t i? 

; thus hydrogen is not as effective as was believed. These 

e contention that hot H chemistry can occur in hydrogen-rich 

planetary atmospheres and can drive organic synthesis in regions where the 

direct photolvsis of methane cannot occur. 

43 
PHOSPHINE PHOTOLYSIS. APPLICATIONS TO 

JOVIAN ATMOSPHERIC CHEMISTRY 

3. P. Ferris*, Alain Bossard and Robert Benson 

Department of Chemistry 

Rensselaer Polytechnic Institute 

Troy, New York 12181 

The discovery of phosphine (PHs) in the atmospheres of Jupiter and Saturn prompted 

renewed interest in PHs photochemistry. It has been suggested that the color of 

the Great Red Spot on Jupiter is due to the rapid transport of PHs from lower 

atmospheric levels to the stratosphere where it is photochemically converted to 

red phosphorus by solar ultraviolet light. Since PHs is present above the cloud 

layers on both Jupiter and Saturn its photolysis to red phosphorus should be 

prevalent and not restricted to specific locales such as the Great Red Spot. 

Laboratory studies of PHs photochemistry were undertaken to provide a better 

experimental basis for these theories. This work will also provide guidance in 

the design of experiments for the Galileo probe of Jupiter as well as for ground 

based infrared studies which will investigate the molecular species present in 

the atmospheres of Jupiter and Saturn. 

Photolysis of PH, with a 207 nm light source gives diphosphine (P2H4) as the 

initial photoproduct. It is formed in the gas phase by the combination of two 

PHz radicals with a diffusion-controlled rate constant (5.4 x 10 M-'s-l) which 

is comparable to that for the formation of NzHb from NH2. Neither N2, SFs nor 

H2 have a significant effect on the rate of formation of PzH4 from PHs or the 

rate of conversion of P2H4 to red phosphorus. Photolysis of PHs-NH3 mixtures 

results in the conversion of the PHs to PzH4 even though NH3 is absorbing 90% 

of the light. This is due to the reaction of PHs with the radical species (NH2 

and H) formed by the photolysis of NHs. 

ature above the melting point (174K). 

P2H4 formation is independent of temperIts rate of formation does not change at 

temperatures below 174K but its stability increases below this temperature due 

to its condensation as a solid. We postulate that the aerosol layer above the 

NH3 clouds (Axe1 or Danielson dust) may be due to P2H4 formed from PHs which 

condenses to a solid at the 110-150K temperatures present in the Jovian stratosphere. Initial quantum yields have been measured for the formation of P2H4 

(0.80), H2 (l.O), and phosphorus (0.04) and for the loss of PHs (1.78). A new 

mechanism is proposed for the photolysis of pure PHs and PHs-NH3 mixtures based 

on these data. 

44 
PHOTOCHEMISTRY OF METHANE, NITROGEN AND CARBON MONOXIDE 

ON TITAN-ABIOTIC SYNTHESIS OF ORGANIC COMPOUNDS 

Yuk L. Yung* Mark Allen Joseph P. Pinto 

Calif. Inst. of Technology Jet Propulsion Lab. Harvard University 

Pasadena, CA 91125 Pasadena, CA 91109 Cambridge, MA 02138 

Edward P. Gardner 

Calif. Inst. of Technology 

Pasadena, CA 91125 

The photochemistry of the major species containing carbon, hydrogen, nitrogen 

and oxygen in the atmosphere of Titan has been investigated using a one-dimensional model with realistic exospheric boundary conditions, vertical transport 

and heterogeneous processes at the tropopause. An extensive set of reactions 

has been compiled and critiqued. To estimate the rate coefficients of reactions 

which have not been measured we employ a number of innovative techniques such 

as Tree's semi-empirical theory for computing three-body recombination rate 

constants. Starting with CHq, N2 and CO, and invoking interaction with 

ultraviolet sunlight, energetic electrons (of magnetospheric origin), and 

cosmic rays, the model predicts correctly the concentrations of all other 

species, as observed by the Voyager IRIS and WS instruments. The model is 

characterized by six simple concepts: (a) escape of hydrogen, (b) secondary 

photolysis of CHq, (c) synthesis of higher hydrocarbons, (d) production of 

photochemical haze layers, (e) coupling between nitrogen and hydrocarbons and 

(f) coupling between oxygen and hydrocarbons. Our results suggest that photochemistry plays a major role in the present day climatology and past evolution 

of the satellite. Titan might have lost the equivalent of 10, 1 and 1 present 

atmospheres of CH4, N2 and CO respectively over geologic time. Most of the 

volatiles were photochemically converted into condensible organic compounds 

and deposited on the surface. The implications of abiotic organic synthesis 

on Titan for the origin of life on Earth are briefly discussed. 

45 
THE ORGANIC CLOUDS OF TITAN 

*Carl Sagan and B.N. Khare 

Laboratory for Planetary Studies 

Cornell University 

N 

In the light of yyager 

was exposed for 10 

1 Titan results, a mixture of 9% CH4 and 91% 

1 

sets at a total pressure of 73 mb to high frequency 

e ectrical discharge. 

other molecules. 

The gas phase products include NH3, HCN, (CN)2 and 

Solid phase products, here called tholins, appear as a 

thin red film which, under scanning electron microscopy, is found to be 

comprised of irregular micron and sub-micron sized particles, with a preponderance of particles exhibiting a radius z 0.3 urn. The wavelengthdependent real part of their refractive indices n"1.6 ? 0.1. These properties 

seem to be consistent with those deduced for the Titan aerosoJs from Earthbased observations (Rages and Pollack, Icarus 41, 119, 1980). Values of --- - 

n(X) and k(X), and the uv, visible and ir reflectivities of these tholins 

have been measured, and compared with the CH /NH and CH4/NH /H S tholins 

described earlier (Khare et al. -- Science E,4119a, 1978; Sazan2and Khare, 

Nature z, 102; 292, 536, 1979). The spectral reflectivity of this tholin 

has been measured between 0.38 and 1.1 urn. The tholin absorbs strongly 

between 0.38 and 0.60 urn, and in this wavelength range follows, within the 

probable errors, the measured reflectance of Titan. At longer wavelengths, 

where the CH Kuiper bands become prominent, the tholin, not masked by CH 

absorption, sontinues to increase in reflectivity. We find that the infrired 

absoption spectra of tholins we have previously reported on can be explained 

by a weighted linear superposition of the absorptions by the most abundant 

organic functional groups appearing as GC/MS pyrolyzates. The infrared 

spectrum of the Titan tholin is similar, and suggests that this material is a 

complex heteropolymer which contains, among others, nitrile and hydrocarbon 

functional groups. The infrared reflection spectra of the Titan tholin 

longward of 6 m and in the near ultraviolet are flat and approximately 

featureless, consistent with Titan observational results from the International 

Ultraviolet Explorer and from the Voyager IRIS experiments, respectively. 

The Titan tholin may include polynitriles with hydrocarbon functional groups. 

It seems likely that the Titan clouds are composed, at least in part, of 

organic molecules, as proposed some years ago (Sagan, Space Sci. Revs., 11, 

73, 1971; Icarus 18, 649, 1973; Khare and Sagan, ibid 20, 311, 1973). - -- 

From the direct ph?olysis of methane alone by ultraviolet light at wavelengths 

shortward of 1440 A, the accumulation of organic tholins on the surface of 

Titan over geological time amounts to a surface layer tens of meters thick. 

Other energy sources serve to increase this number. At the 95°K surface 

temperature of Titan these organic heteropolymers will tend to be preserved 

for very long periods of time. It is therefore possible that the surface 

of Titan is a planet-scale rep sitory of some of the early steps which led 

on Earth -- more than 4 x 10 8 years ago and in the presence of liquid 

water -- to the origin of life. It is also conceivable that the abundant 

water ice in the interior of Titan (deduced from the satellite's bulk density) 

is intermittently released in liquid form to the surface, and that subsequent 

aqueous tholin chemistry occurs even if episodically and on local scales. 

46 
SESSION I I 

PRIMITIVE EARTH 

47 
~ --.. . . . ..- - ._. ___... ---..~- 

PHOTOCHEMISTRY OF METHANE IN THE EARTH'S EARLY ATMOSPHERE 

1 J. F. Kasting', K. J. Zahnle *2 J. C. G. Walker2 

NASA-AMES Research Center, Moffei Field, California 

2The University of Michigan, Ann Arbor, Michigan 

The photochemistry of methane in the primitive terrestrial atmosphere is 

potentially interesting in regards to both the origin and evolution of life. 

Methane has long been a favored starting point for the chemical evolution of 

life. If it were present in the primitive atmosphere, methane's photochemical 

byproducts, which can include formaldehyde, hydrogen cyanide, etc., would have 

formed ready source material for the subsequent biochemical evolution of amino 

acids, nucleic acids, and other basic building blocks of living matter. 

Once life had formed, methane could easily have played a role in the co-evolution of life and the atmosphere. Methane would have been produced by the 

methanogens, an ancient class of anaerobic life that presumably were alive Aand possibly flourishing -- in the anaerobic biosphere that characterized the 

first 1.5 billion years of terrestrial life. A fraction of this methane would 

have polymerized into more complex hydrocarbons. Infrared absorption by methane 

and especially by other hydrocarbons may have supplemented the greenhouse warming due to CO2 and H20, thus counteracting the cool sun and raising the possibility that the Gaia hypothesis may have applied to the anaerobic earth and its 

transition to aerobic conditions. (Speculation: the destruction of the methane 

greenhouse early in the Proterozoic may have triggered the Huronian glaciation.) 

We present here a detailed series of one-dimensional numerical models for methane 

photochemistry in the anaerobic terrestrial atmosphere. The model solves the 

coupled equations of photochemical production (and loss) and diffusion for 22 

chemical species, an additional 12 species are put in photochemical equilibrium. 

Steady state CH4 mixing ratios of 10s6 to greater than 10m4 cculd have been maintained by a methane source of about 1011 molecules cm-2sec-1 [global average), 

which is comparable to the modern biogenic production rate, though a couple of 

orders of magnitude less than the modern abiogenic production rate. Thus, we 

find that methane-rich biogenic atmospheres are inherently plausible. In the 

absence of a source, methane would have disappeared in some lo4 years in a series 

of chemical reactions initiated by reaction with either OH or 0, being oxidized 

or being polymerized into more complex hydrocarbons. The source strength needed 

to maintain a steady CH4 mixing ratio and the degree to which it would have 

polymerized depend strongly upon the amount of CO2 present, while the dependence 

upon H2 is much weaker. Our calculations also suggest that atmospheres rich in 

both CO2 and CH4 may be photochemically unstable with respect to conversion to CO. 

48 
P 

PHOTOCHEMICAL REDUCTION OF CARBON MONOXIDE IN THE EARTH'S PRIMITIVE ATMOSPHERE 

Akiva Bar-Nun and Sherwood Chang* 

Extraterrestrial Research Division 

NASA-Ames Research Center 

Moffett Field, California 94035 

The absence of a geological record makes a firm assessment of the atmospheric 

composition during Earth's first 0.8 billion years virtually impossible. 

Suppositions for the atmosphere range from H2-rich, containing H2-CH4-NH3-N2-H20-H2S, 

to H2-depleted, containing CO-C02-N2-H20-S02. Although organic syntheses in H2-rich 

mixtures has been studied extensively, relatively little work has been reported 

on the CO-C02-N2-H20 system. Since solar radiation is the most abundant energy 

source in the atmosphere, photolytic investigations of the latter mixture are 

essential for an assessment of the full range of possibilities for the synthesis 

of organic matter on the primitive Earth. The photochemical experiments summarized 

below focused on the purely gas phase reactions of H20, CO, CO2 and N2; they were 

intended both to elucidate production mechanisms and to simulate reactions that could 

have occurred on the prebiotic Earth either above the cloud tops, at altitudes of 

about 10 km, where the abundance of water vapor is still considerable, or in an 

atmosphere containing few clouds. 

Gas mixtures containing H20 and CO with various proportions of H2, C02, and N2 were 

irradiated with 185 nm light or a simulated solar spectrum from which short wavelength UV was blocked by a filter cell containing 02. Alchols, aldehydes, hydrocarbons, acetone and acetic acid were produced; no nitrogen-containing organic 

compounds were detectable. The initial step in the reactions involved photodissociation of H20 molecules to yield hot H-atoms and hydroxyl radicals; the former 

reduced CO and recombined to H2, while the latter oxidized CO to CO2 and generated 

additional H-atoms. Changes in gas composition with irradiation time suggest that 

the organic products arose from a series of consecutive reactions in which CO was 

converted first to aldehydes and alcohols, which then were further hydrogenated 

to hydrocarbons. The overall apparent quantum yield for conversion of CO to organic 

carbon varied between 0.23 and 0.03 as a function of CO abundance. These results 

indicate that, even if the primordial atmosphere contained carbon only in the form 

of CO or a mixture of CO and C02, and no molecular hydrogen, a variety of organic 

compounds would have been produced by gas phase photochemical processes. 

Upper and lower bounds can be crudely estimated for the "average" concentration of 

organic carbon in a hypothetical "global" ocean resulting from rain-out of products 

produced solely by photolysis of H20 in the presence of CO. These calculations 

are made in the context of existing models for formation of the atmosphere and 

rely on estimates of primordial UV fluxes and terrestrial H and C inventories 

coupled with the apparent quantum yield for synthesis of organic C. For the case 

in which the total carbon inventory is released as CO over lo8 years, in 106 years, 

the concentration organic C could have been as high as 0.02 M in a global ocean 

30 m deep. For the case in which CO was released as a minor constituent and the 

atmospheric generation time was 5 x lo8 years, the concentration would have been 

0.0004 M. Gas phase photochemistry was certainly only one of the many possible 

sources of prebiotic organic matter. It is also unclear whether the types and 

amounts of organic compounds discussed above were necessary or sufficient for chemical 

evolution of organic matter to proceed beyond the monomer stage to attain higher 

levels of molecular organization. A satisfactory answer to this larger question 

awaits a more thorough accounting of the sources of simple organic compounds and 

the pathways for their conversion to more complex systems on the prebiotic Earth. 

49 
JHE ATMOSPHERE OF THE PRIMITIVE EARTH AND THE 

PREBIOTIC SYNTHESIS OF ORGANIC COMPOUNDS 

Stanley L. Miller*and Gordon Schlesinger 

Department of Chemistry, B-017 

University of California, San Diego 

La Jolla, California 92093 

There is considerable controversy concerning the composition of the 

earth’s atmosphere at the time of synthesis of the organic compounds which 

organized into the first living organism. Compositions proposed range 

from strongly reducing atmospheres containing CH4 to more oxidized atmospheres 

containing mainly CO2 as the carbon source. 

concerning the presence of NH 

There is also a controversy 

ion in the primitive ocean. a 

in the atmosphere and as a consequence NH4+ 

partial pressures of 10v8 

pinion varies from no NH3 and NH4+ at all to 

to 10-6 atm of NH and 10-3 to lo-* M NH + in 

the primitive ocean. It is generally agree d that 52 was absent. 4 here is 

no geolo 

!J 

ical evidence about the composition of the atmosphere at 4.0 to 

4.6 x 10 years a o. 

dated at 3.8 x 10 !ii 

The oldest known rocks, the Isua formation of Greenland, 

years obviously cannot provide evidence for conditions 

on the earth 0.5 x 109 years before they were formed. Although a number of 

prebiotic synthesis experiments using CO or CO2 instead of CH4 as a carbon 

source have been reported,, there has never been a systematic investigation 

of the comparative products and yields. 

We have studied the prebiotic synthesis of organic compounds using a 

spark discharge as a source of energy. Methane mixtures contained H2 + CH4 

+ H20 + N2 + NH3 with H2/CH4 ratios from 0 to 4 and pNH3 = 0.1 mm. The 

yields of amino acids were approximately independent of the H2/CH4 ratio 

(1.5 to 4.7% yield based on the carbon), and a wide variety of amino acids 

were obtained. Mixtures of H2 + CO + H20 + N2 + NH , H2 + CO + H 0 + N 

H2+C02+H20+N2+NH3,H2+C02+H20 +N2, al7 gave about 2g yielgl 

of amino acids at H /CO and H2C02 ratios of 2 to 4. For the H2/CO and 

G? 

H /CO2 ratios less z han 1, the yields fall off drastically (as low as lo-3%). 

ycine is almost the only amino acid produced from CO and CO2 atmospheres. 

These results show that the maximum yield is about the same for the 

three carbon sources at high H2/carbon ratios, but that CH4 is superior at 

low H2/carbon ratios. In addition, CH4 gives a much .greater variety of 

amino acids than either CO or C02. If it is assumed that the more complex 

amino acids were required for the origin of life, then these results indicate 

the need for CH4 in the primitive atmosphere. 

The hydrogen cyanide and formaldehyde yields parallel the amino acid 

yields; yields of HCN and of H2CO as high as 10% based on the carbon were 

obtained in some experiments. NH is also produced in experiments with no 

added NH3 in yields as high at 4. 2 %. These results show that large amounts 

of NH3 would have been synthesized on the primitive earth by electric 

discharges. The amount of ammonia formed by hydrolysis of the HCN may have 

exceeded that formed directly in the electric discharge. 

50 
I 

Chemical Evolution and Model Photosynthetic Protocells 

Clair E. Folsome* 

Exobiology Laboratory 

University of Hawaii at Manoa 

Honolulu, Hawaii 96822 

Can biochemicals be synthesized under plausible primordial 

geochemical conditions? Current views of the primitive 

terrestrial environment suggest an atmosphere of nitrogen, water 

vapor and present-day abundances of carbon dioxide. This research 

asks whether organic compounds can be made under these anoxic 

conditions from simple precursors as C02, water and various 

nitrogen sources, using long wavelength ultraviolet energy. 

Implicit in this approach is the idea that primordial 

biochemistry centered about photosynthetic reactions mediated by 

phase-bounded systems. 

We have shown several routes which lead to the synthesis of 

organic compounds under anoxic conditions. (1) Synthetic cellsized .organic microstructures effect the long-wavelength 

ultraviolet photosynthesis of formaldehyde, amino acids and other 

compounds from water, carbonate and various simple nitrogen 

sources (Nature 291: 482, 1981). Electrical discharges through 

----- nitrogen upon aqueous suspensions of calcium carbonate result in 

the formation of hydrazine, carbohydrazides and other organic 

products (Nature 294: 64, 1981.). These data show that the anoxic 

primordial atmosphere model is sufficient to account for the 

genesis of organic compounds during the origin of life. More 

recent data, summarized below, indicate that the anoxic 

photochemical model yields a wide variety of organic molecules of 

biochemical interest. 

Recent findings: When aqueous suspensions of CaC03, 14C-labeled 

formaldehyde, and hydrazine are exposed to long wavelength UV 

(254 nm) the following products are obtained: (1) free amino 

acids, (2) uracil and other dihydropyrimidines, (3) deoxyribose 

and other sugars, (4) organic microstructures, (5) other as yet 

unidentified organic products. Identification was effected by 

extensive thin layer chromatography, by gas chromatography/mass 

spectrometry, and by liquid chromatography (the 14-C label of 

the input formaldehyde was recovered in these products). This is 

the first instance in which pyrimidines, deoxyribose, amino 

acids, and organic structures have simultaneously been recovered 

in good yields from a single photochemical reaction. 

51 
CLAYS AND THE ORIGIN OF LIFE 

Hyman Hartman* 

Massachusetts Institute of Technology 

Cambridge, MA 

Clays are made up of various ions imbedded in a layered silicate structure. 

The ions involved are mainly aluminium, iron and magnesium. Clays are formed 

when water caused the chemical weathering of rocks. The concentration of ions 

in clays (e.g., iron, magnesium) is extremely variable and thus clays can be 

considered solid solutions. In 1965, Cairns-Smith proposed that the original 

genes were clays. The distribution of ions played the role of bases in DNA. 

Recently, A. Weiss has replicated clays in the laboratory for twenty-two 

generations. We have proposed that it was on the surface of replicating ironrich clays that carbon dioxide and nitrogen would be fixed into organic molecules. 

The synthesis (low temperature and pressure) of iron-rich clays are being carried out. The syntheses of glauconite and nontronite has been successful. 

The interaction of coenzymes with homoionic clays has been studied, in particular the interaction of pyridoxal phosphate and Cu montmorillonite. An activation of the coenzyme by the clay was demonstrated. The interaction of 

phospholipids and Ca* montmorillonite led to the formation of a lipid bilayer 

between the clay particles. We are now studying the phase transitions of the 

lipid bilayer by physical and chemical means. The reduction of carbon dioxide 

to formaldehyde in the presence of Fe * ion and light has been demonstrated by 

Getoff, we have looked at the inverse process which involves the oxidation of 

sugars by Fe* ion and light. This implies that the iron cycle would be coupled 

to the carbon cycle, very early in chemical evolution. We are thus looking for 

a photosynthetic organism which would use the electrons from a ferrous ion to 

reduce carbon dioxide. Finally we are modeling the synthesis of polar organics 

on carbonaceous chondrites. Our model suggests that y radiation supplied by 

A 126 reduced the carbon dioxide and nitrogen on the surface of the iron-rich clays. 

52 
THE ADSORPTION OF BIOMONOMERS ONTO HOMOIONIC CLAYS 

S. Bzik, F. Church, J. Lawless? N. Levy, J. Mazzurco and M. Mortland 

NASA-Ames Research Center 

Moffett Field, CA 94035 

In previous studies, we have shown that Zn-bentonite strongly adsorbed the purine 

nucleotides, and specifically adsorbed 5' -AMP from a mixture containing 5', 3', 

and 2'-AMP. This behavior is not predicted from homogeneous solution behavior 

and will be discussed. Excess NaCl in the solution does not significantly change 

the adsorptive behavior of the nucleotides. The presence of zinc or magnesium 

in solution will enhance the adsorptive behavior of ATP onto Zn-bentonite, while 

magnesium in solution will not effect the limited adsorption of ATP onto Mgbentonite. Smectites with polyvalent cations on the exchange sites readily 

adsorb riboflavin from aqueous solution. Finally, Ca-vermicullite showed no 

adsorption, suggesting that this mineral does not swell sufficiently to permit 

intercalation. Temperature appears to have a significant impact on the 

adsorption of amino acids (alanine, S-alanine, b-aminobutyric acid) onto Cubentonite. Implications for our studies in chemical evolution and the origins 

of life will be discussed. 

53 
CATALYSIS OF PEPTIDE FORMATION ON CLAY SURFACES 

BY POLYRIBONUCLEOTIDES AND BY SHORT PEPTIDES 

David H. White* 

Chemistry Department 

University of Santa Clara 

Santa Clara, CA 95053 

The origin of genetic processes and the appearance of collections 

of molecules which could reproduce themselves are the least understood aspect of the origin of life on the primitive Earth. The 

objective of this research is to demonstrate that simple molecules 

could carry out catalysis and templating during peptide bond formation, which might lead to a crude but spontaneous laboratory 

model for primitive translation. 

Glycine reacts to form peptides on the surface of clays which are 

alternately wetted and dried. We have shown that the mechanism of 

this reaction involves the formation of an activated acyl silicate, 

which is analogous to the acyl phosphates (amino acid adenylates) 

which provide the energy for protein synthesis in living cells. 

The reaction of glycine on clays is catalyzed to a remarkable 

extent by histidyl-histidine and other peptides. Only 2 nmol of 

His-His promotes the formation of 100 nmol of additional glycine 

peptides. This suggests that His-His is a model for a primitive 

enzyme, able to repeatedly catalyze the synthesis rather than 

degradation of biologically important molecules. Polyribonucleotides also catalyze the reaction of glycine on clay surfaces7 and 

we have recently demonstrated that 10 nmol of Poly G promote the 

formation of 40 nmol of additional peptide, which is the first time 

that greater than stoichiometric results have been obtained. For 

this and several other reasons, we believe that a simple template 

is involved in this reaction. We are trying to demonstrate directly 

that templating is involved, and that polyribonucleotides can 

select certain amino acids preferentially from a mixture, but so 

far we have not succeeded. Theoretical work by the author suggests 

that peptide catalysts might enhance the selectivity of a template, 

so our eventual goal is to demonstrate whether this effect can lead 

to a significant translation effect. 

54 
SOLVATION/DESOLVATION INDUCED LUMINESCENCE IN 

KAOLIN - INDICATOR OF SURFACE REACTIVITY? 

Lelia M. Coyne* 

San Jose State University/Ames Research Center 

Electronic excitation produced by diverse energy sources can 

be similarly stored in catalytic minerals as separated traoped 

charges. My research of the last several years has produced an 

elaborate web of circumstantial evidence which links this energv 

to the chemical reactivity of adsorbed orqanic molecules important 

to the origin of life. If it can be shnwn irrefutably that a 

genlline link exists between energization of a mineral catalyst and 

reactivity of adsorbed organics, then it can be arqued that chemical 

evolution would have proceeded much more rapidlv than our laboratory 

simulations of it. I am exoloring this link bv correlating mineral 

luminescences, ESR and chemical reactivity as a function of preheating-and pre qamma irradiation of the mineral catalvst. 

Investigations of glycine oliqomerization on pretreated kaolin 

using a wet/cold hot/dry cycled reaction protncol have shown that 

the yield of peptide bonds can be enhanced by thermal and gammairradiative nretreatment of the kaolin. TL efficiency also varies 

as a function of these pretreatments. Whether the two sets of 

results are correlated is currently under investigation. As the 

outgrowth of efforts to see if energization of kaolin could be 

achieved by mechanical stress also, Noam Lahav and I discovered 

a novel luminescent phenomenon in kaolin. Blue to near U.V. liaht 

is released by drying a water-wet paste of kaolin. The efficiencv 

of this luminescent Process, like TL and glycine oliaomerization, 

is affected by thermal and radiative treatment of the kaolin. More 

recent studies have indicated that light is induced also when 

organic amines are added to, or removed from the kaolin surface. 

These luminescent orooerties also are influenced by thermal and 

aamma-irradiative treatments. Presentlv research efforts are being 

directed towards understandina the origins of desolvation-induced 

luminescence, both in terms of its molecular center and its modes 

nf excitation. The role of the surface attraction of clay to water 

is being investiaated usina hallovsites. The reactivity of the 

clay surface to glycine oliqomerization is beinq explored in relationship to the electronic structure and excitation of kaolin. 

Correlations are beina made between glycine oligomerization, electronspin-resonance, thermoluminescence, solvation/desolvation-induced 

luminescences and kaolin absorption spectra as a function of heat 

and gamma-irradative treatments. 

55 
Prebiotic Formation of Phosphoanhydrides, like ATP, 

by Chemical Pathways that Resemble Fermentation (Glycolysis) 

Arthur L. Weber” 

The Salk Institute 

San Diego, California 92 138-92 16 

All organisms require energy in a chemical form for maintenance and growth. 

Contemporary life obtains this chemical energy by the synthesis of the phosphoanhydride bond, such as that in ATP (adenosine-5’-triphosphate). Fermentation 

appears to be the simplest and probably most primitive method that organisms 

use to synthesize the “energy-rich” phosphoanhydride bonds of ATP. Fermentation is considered primitive because it does not require oxygen or light, and 

operates in solution without a need for organized compartmentation. The 

mechanism of formation of phosphoanhydride bonds in fermentation is called 

“substrate-level phosphorylation”. Under anaerobic conditions substratelevel phosphorylations frequently occur by the oxidation of an aldehyde to give 

an “energy-rich” thioester, which is subsequently used to drive the formation 

of the phosphoanhydride bonds of ATP [aldehydeoxidation)thioester ,-B phosphoanhydride bonds of ATP]. It is our contention that a related sequence of 

non-enzymatic chemical reactions provided the chemical energy needed for the 

origin of life on the primitive Earth. 

The chemistry of this reaction pathway [aldehyde Oxidation)thioester .-> 

phosphoanhydride bondsJ is being studied in order to understand its role as a 

source of chemical energy for the origin of life, Thioesters have been formed 

in aqueous solution at neutral pH by (1) oxidation of acetaldehyde with a disulfide in the presence of ultraviolet light and (2) intramolecular oxidation-reduction 

of pyruvaldehyde catalyzed by a thiol. Thioes ter formation from glyceraldehyde 

is suggested by preliminary experiments that show thiol-dependent formation 

of lactic acid and glyceric acid from glyceraldehyde in solution at neutral pH. 

The significance of this reaction with glyceraldehyde is emphasized by the 

central energy-yielding role of glyceraldehyde-3 -phosphate in the biochemical 

pathway of glycolysis. The formation of phosphoanhydride bonds with thioesters as the condensing agent has also been studied under prebiotic conditions. 

Acetyl thioester has been shown to drive the synthesis of the phosphoanhydride 

bonds of (1) pyrophosphate and tripolyphosphate under drying conditions, (2) 

phosphorylimidazole in aqueous solution and (3) pyrophosphate, tripolyphos - 

phate and phosphorylimidazole in the presence of Cat2 and water. “Energyrich” thioesters have also been shown to bring about the synthesis of pyrophosphate on hydroxyapatite, a phosphate mineral. In these investigations 

products derived from radioactive substrates were separated by chromatography or electrophoresis and then measured with a radiochromatographic 

scanner. 

56 
EXPERIMENTS ON THE ORIGIN AND AMPLIFICATION OF MOLECULAR CHIRALITY 

William A. Banner* 

Stanford University 

Stanford, California 94305 

The origin of optically active molecules in nature 'poses a question- intimately related to those of the origin of chiral biopolymers and of life itself- which has 

intrigued scientists since the time of Pasteur, but which still lacks definitive answers. During the intervening years a number of plausible physical mechanisms has 

been proposed for the abiotic genesis of chiral molecules, but experimental verifications of such mechanisms have been inconclusive or open to criticism. Because 

of the philosophical importance of the question, and since the validity of such 

mechanisms bears directly on the applicability of optical activity per se as a criterion for extraterrestrial or archaen life, we have reinvestigated a number of 

these mechanisms using modern experimental techniques. In general our approach has 

been to subject DL-amino acids (or derivatives), as prebiotically realistic substrates, to various chiral physical forces or environments, then to examine the recovered substrates for optical activity (i.e. an excess of one enantiomer, D # L) 

usi,ng analytical gas chromatography, a technique superior for these purposes to 

conventional polarimetry. The several types of experiments which led unambiguously 

to the generation of optical, activity were briefly the following: 1) DL-amino acids 

or certain derivatives proved subject to ASYMMETRIC ADSORPTION on the surfaces of 

finely powdered d- or l-quartz, with engendered enantiomeric excesses (e.e.'s) ranging from 1.5 - 12.5%; 2) DL-leucine underwent ASYMMETRIC PHOTOLYSIS with 212.8 nm 

right or left circulary polarized light, the e.e. reaching 2.5% after 75% photolysis; 

3) in experiments designed to mimic natural B-decay electrons, the irradiation of 

DL-leucine with parallel ("right-handed") or anti-parallel ("left-handed") spin 

polarized 120 KeV electrons from a linear accelerator led to ASYMMETRIC RADIOLYSIS, 

with e.e.'s varying from 0.6 - 1.4%. These results were not subsequently duplicated 

using a different polarized electron source. 

7 

-Radiation and Bremsstrahlen from a 

number of natural B-emitting isotopes (9OSr, 4C, 32P) led to no asymmetric radiolysis of DL-leucine, nor did irradiation with longitudinally polarized protons from 

a cyclotron. In these studies it was found that racemization of amino acids accomf'anied their exposure to ionizing radiation. Such RADIORACEMIZATION diminishes the 

efficacy of the above B-decay mechanism, and has been a separate subject in our 

more recent investigations. 

The e.e.'s abiotically generated in the above experiments were typically only a few 

percent- smaller than might reasonably be thought adequate for the direct genesis of 

a primitive biosphere. Additional abiotic mechanisms for the subsequent chemical amplification of such small e.e.'s would clearly be stereochemically advantageous for a 

prebiotic molecular evolution toward the stereospecific biomolecular processes of 

the contemporary biosphere. More recent successful experiments, focused on potential 

mechanisms for the abiotic amplification of such small e.e.'s include the following: 

1) D # L Mixtures of ieucine N-carboxy anhydride monomers having a known e.e. were 

subject to ca. 50% polymerization. The e.e.'s of the resulting polymers were examined (after hydrolysis), and found to be uniformly higher than the e.e.'s of the 

initial monomers, demonstrating that enantiomeric enrichment can occur during partial 

polymerization; 

tial hydrolysis, 

2) D # L polyleucine oligomers of known e.e. were subjected to parand the e.e.'s of the recovered monomers. and unhydrolyzed polymers 

were examined. The monomer hydrolysate leucines proved to have lower e.e.'s, and the 

unhydrolyzed polyleucine residual polymers to have higher e.e.'s than the original 

polyleucine oligomers, indicating that e.e. enhancement can occur in the polymer residue from the partial hydrolysis of an enantiomerically enriched polypeptide. On the 

basis of these sets of experiments a cyclic "polymerization-hydrolysis" mechanism 

has been proposed for the possible abiotic formation of enantiomerically homogeneous 

polypeptides on the. primitive Earth. 

57 
Adsorption of Biaruolecules (5'-Nucleoside Wnophosphates 

andAminoAc.ids) onto-ionic clay Surfaces 

Jm-~s B. Oren&rg* 

lZepartmentofChgnis+sy 

Sankancisco StateUniversity 

Bernal in 1941 first suggested that clays may have played an 

important role in chemical evolution. The results of investigators since 

that tiara, andespecially in the last5 years,havelentproofto this 

hypothesis. More specifically, investigations have shwn that selected 

n-&al ions substituted into the naturalcationexchange sites on the 

surfaces of clays may have played a significant role in chemical evolution. 

Clay surfaces are of keen interesttoprebiotic chemists andchenical 

evolutionists because they have recognized the possibility of specific 

adsorption and thus concentratianofprebioticrrronaners on these surfaces 

leading to condensation and prcductian of bio-oliganers. The study of the 

interaction of significant biarclecules (e.g., 5'-nucleoside monofiosphates 

and-acids) withhomoionic substitutedclays shouldshrxJwhether these 

bionic clay surfaces exhibit selectivity in interactian with these biomolecules. Such information is imperative to formulating intelligent conclusions 03n caning the likely role of hcmxn-te tallic clay surfaces in chemical 

evolution, especially as a template surface, and the relationship of the 

role of metal cations in the present day genetic apparatus. 

The introduction of selected metal cations @In 2+, Fe 3-l- 

, Co2+, Ni2+ 

and Zn2+) at the cation exage sites in montmorillonite clay remarkably 

alters the binding behavior of biarolecules which normally do not bind 

readily onto the surface of naturally occurring monmrillonite clay in 

anaqueousemrironm~~t. Using only arcmatic biarolecules we have observed 

larger binding for 5'-AMP over 5'-cIMp and lYp over Phe on -ionic clay 

surfaces. The order of binding selectivity of clays substituted with a 

retalcation for the different arunaticbicarolecule ligandsvariedwithin 

the nucleotides and amino acidsused. Adherence to the Irving-Williams 

metal-ligand binding series was not observed in all cases; selectivity in 

binding of ametalcation situatedina cationexchange siteona clay 

surface seems to be more axnplex than Ixarogeneous, aqueous metal ligand 

binding. A series of nonaranatic amino acids (gly, ala, B-ala and sarcosine) 

are also being sixrdied. 

58 
SESSION III 

INFORMATION TRANSFER 

59 
NMR STUDIES OF INTERACTIONS BETWEEN NUCLEIC ACIDS AN9 PROTEINS 

Cyril Ponnamperuma, Mitchell Hobish*, and Binny Cherayil 

Laboratory of Chemical Evolution 

Department of Chemistry 

University of Maryland 

College Park, MD 20742 

The origin of life on earth is inextricably intertwined 

with the origins of the genetic code. Since the present-day 

biological processes include both replication and information 

transfer, the study of these phenomena may provide some clues 

to the emergence of life. As an approach to the problem, we 

have chosen to study the specific physical chemical interactions 

between constituents of nucleic acids and proteins. 

Nuclear magnetic resonance spectroscopy can provide data 

on such relationships. The availability of sensitive NMR 

instrumentation and comprehensive computer facilities make it 

possible to investigate some of the basic questions with regard 

to the nature of interactions between, mono-, di-, tri-, and 

oligonucleotides and mono-, di-, tri-, and oligopeptides. 

In our preliminary studies of AMP/l-Phe-OMe interaction, we 

have found that: 

1. Mg2+ affects the protons of 5' AMP involved in the 

Phe interaction 

2. the signals of the 5' AMP ring protons are shifted 

downfield by the presence of Mg 

3. L-Phe-OMe appears to bind to the 5' AMP (anti-codon 

monomer) more tightly than to the 5' UMP (codon monomer) 

4. interactions between 5' AMP and various dipeptides 

(gly-tyr, gly-phe) results in downward shifts of 

ring proton signals. 

These results may contribute to our understanding of the nature 

of the relationship between nucleic acids and proteins. 

60 
. ..__.__ -- ,._,.,, _,_,- - .._ --..- -----.. 

_.... - - 

. . ..m... -.- . . . . . . . . . ..__--..---.... ,.... - ,,m.__.e----.. 

III -- 

I 

4% 

:, ,‘. 

\.I 

.+, 

i 

$3 

CYANAMIDE MEDIATED PREBIOLDGICAL SYNTHESIS OF 

PHOSPHOLIPIDS, OLIGOPEPTIDES AND OLIGONUCLEOTIDES 

J. Oro* 

University of Houston 

Houston, Texas 77004 

In the study of chemical evolution one of the most important reactions is the condensation of monomers into biochemical compounds which are essential for life processes. These include phospholipids, oligopeptides and oligonucleotides. Phospholipids are presumed to be necessary for the formation of bilayered membranes, oligopeptides for catalysis, and oligonucleotides for replication. This step in chemical 

evolution is crucial not only because of the relevance to life of the synthesized 

compounds, but also because it has to be carried out under geologically plausible 

conditions compatible with the emergence of life. Work carried out in our laboratory during the past years has shown that these three types of compounds can be synthesized in aqueous systems by means of cyanamide. 

Using a primitive Earth evaporating pond model the prebiotic synthesis of phosphatidylcholine was accomplished for the first time when a reaction mixture of choline 

chloride and di-sodium phosphatidate, in the presence of cyanamide was evaporated 

for a few hours. Optimum yields of about 15% were obtained at 80°C. The synthesis 

was also observed at lower temperatures. Similar conditions led to the synthesis of 

another vital phospholipid, phosphatidylethanolamine. Membranous structures in the 

form of oligolamellar and multilamellar liposomes were readily obtained from these 

prebiotically synthesized phospholipids. The synthesis of three histidyl peptides 

in yields of up to 11% was demonstrated when aqueous solutions of histidine, leucine, 

cyanamide, and MgC12 were evaporated and heated for 24 hrs at 80°C. Although the 

above syntheses occur better at a slightly acidic pH the formation of these compounds 

was also demonstrated for systems adjusted to pH 7 with NH40H. For the synthesis of 

oligonucleotides the evaporation pond model can be modified and made more effective. 

Thus a reaction system incorporating several consecutive cycles of evaporation leads 

to the rapid synthesis of oligonucleotides up to at least the tetranucleotide in 

yields of more than 20%. This system has a high degree of prebiotic plausibility in 

that the reaction proceeds well at 37" and 60°, it uses the unactivated nucleoside 

monophosphate, it occurs at neutral pH in the presence of ammonium chloride, and the 

prebiological agent cyanamide is more efficient at producing oligomers longer than 

the trimer than is a chemical condensing agent in the carbodiimide family. Of a 

number of condensing agents tested, cyanamide is the most active under the simulated 

prebiological conditions mainly due to stereochemical effects. Several poly amino 

acids (poly His, poly Arg) increase the yield o.f condensed product in the presence 

of cyanamide which, in line with our earlier observations show that imidazole also 

increases the yield. A discussion of the role of cyanamide, imidazole and arginine 

derivatives leads to the conclusion that a proton relay mechanism between the (N=C-N)- 

group common to the above three compounds may be operating in the prebiotic synthesis 

of the phospholipids, oligopeptides and oligonucleotides. Also a similar mechanism 

may be responsible for similar syntheses in living systems catalyzed by the imidazole 

and arginino groups of the corresponding enzyme active centers. Prebiotic cyclic 

processes imposed by external factors is a way to reconcile the nearly opposite conditions required for oligomerization and replication. An obvious next step is to 

attempt a prebiotic template directed oligomerization using simple or unactivated 

nucleoside monophosphates in such a system. This work was done with the collaboration 

of J. Eichberg, M. Rao, D. Odom, J. Hawker and T. Yamrom. 

61 
AN RNA POLYMEEASE MODEL 

Leslie E. Orgel*, Tan Inoue, and Habib Fakhrai 

The Salk Institute for Biological Studies 

San Diego, CA 

We have developed an ENA polymerase model in which a poly(C) template 

directs an efficient synthesis of oligo(G)'s up to at least the 40-mer. 

The reaction proceeds in a Watson-Crick double helix and has high 

regiospecificity and fidelity. 

Mixed templates containing an excess of C direct an efficient synthesis 

of mixed oligomers containing an excess of G and smaller amounts of 

the bases complementary to the minor constituents of the template, 

Bases whose complements are absent from the template are not incorporated 

into product. 

62 
Self-Ordering -t Reverse Translation? 

Sidney W. FoxT Tadayoshi Nakashima, and 

Robert M. Syren 

Institute for Molecular & Cellular 

Evolution, University of Miami 

The track of molecular evolution has been followed from nonrandom polymerization of sets of amino acids through early 

informational cells into the beginnings of cellular metabolism. 

The polyamino acids characterized as precursors of living cells 

reveal order of a kind that is consistent with a context of recent 

inferences by astrophysicists of a Universe that was ordered from 

the beginning, at another level. The extensively verified fact of 

self-sequencing of amino acids makes a consistent overview out of 

the interpretation that thermal proteins (proteinoids) could have 

served as the first bioinformational molecules and the first specific 

metabolic catalysts. The microspherical aggregation products of the 

proteinoids (microspheres) have been found to be either less heterogeneous in size or more heterogeneous in size than microfossils or 

modern algae. Some artificially fossilized microspheres are 

indistinguishable from algae artificially fossilized by micropaleontologists. 

The most recent research has shown that thermal proteins 

containing sufficient basic amino acid catalyze the synthesis of 

peptide bonds between all types of amino acid. Such polymers 

function as catalysts in solution, in proteinoid microspheres 

composed of both acidic and basic proteinoids, and in complexes of 

basic proteinoids and polynucleotides. The energy-providing agent 

can be either pyrophosphate or ATP; both high-energy phosphate and 

catalytically active lysine-rich proteinoid are, however, needed. 

Repeated infusion of ATP results in higher yields of peptide than 

does a single batchwise inclusion of the same total amount of ATP. 

The identity of the polynucleotide in polynucleotide-proteinoid 

complexes influences the proportion of gly-phe and phe-gly synthesized from gly and phe. Extension of the phenomena observed, plus 

an earlier demonstration that basic proteinoids catalyze the 

formation of internucleotide bonds, are allowing an experimental 

modelling of the recently revived concept of reverse translation. 

63 
Possible Pathways Towards the Evolution of the Genetic Code 

F.R. Eirich*and M. Paecht-Horowitz 

Polytechnic Institute of New York and 

Dept. of Agriculture, Hebrew University of Jerusalem, Rehovot 

The study of chemical evolution was so far able to uncover possible pathways 

for the prebiotic synthesis of practical all small building blocks of the biochemicals of living systems. It has further thrown considerable light on the 

several ways of spontaneous synthesis of oligomeric peptides and RNA-type nucleotides. However, because of systematic and synthetic difficulties, bio-oligomerstudies were carried out on systems of only one kind, e.g. protenoids, sugars, 

nucleotides. We know next to nothing about possible effects of the developments 

of one type of potential bio-molecules on another, let alone about any evolutionary interaction that might have formed the basis for the occurrence of aminoacid sequences, base pair coding, or readion aiding stereochemical configurations 

as precursors of enzymatic sites. 

Studying the polycondensation of adsorbed activated amino acids (AA) we established the adsorption isotherms of AA’s and nucleotides, the existence of specific 

molecular weights related to the type of adsorption, and we observed also peculiar 

ways, by which preadsorbed peptides affect MW of the next generation. 

We are working now on adsorption isotherms of the principal participating nucleic 

acid components and also on the co-adsorption of AA’s and peptides with purinepyrimidine bases and their nucleotides. As a result we expect to assist the adsorption of AA’s by adsorbed nucleotides, also to help the adsorption of the 

latter by preadsorbed bases, and we are looking into the possibility that the 

interaction cfgrowing nucleotides and AA’s might lead to a development of primitive complexes. 

Whatever the results, they should cast some light on a possible regular coevolution of these primitive building blocks for emerging life, on potential 

interactions that led to the evolution of the genetic code and to the emergence 

of some protenoids with enzymatic capabilities. 

64 
I - 

THE CHEMICAL BASIS FOR THE ORIGIN OF THE GENETIC CODE 

AND THE PROCESS OF PROTEIN SYNTHESIS 

James C. Lacey,* Jr. 

University of Alabama in Birmingham 

Birmingham, AL 35294 

Certainly it is one of the defined characteristics of contemporary living 

things that they respond to environmental changes (stimuli), not only by simple, 

direct, and predictable chemical reactions, but also by indirect, complex, 

nucleic acid mediated responses requiring the synthesis of mRNA and then active 

principles, protein. One of NASA's goals is to understand how life originated, 

and our efforts to understand how the process of protein synthesis and the 

genetic code came to be are an essential part of that understanding. 

Conceptually, the problem has two parts: (1) the chemical reactions involved 

in the process of protein synthesis, and (2) the consistent relationship between 

sequences of nucleotides in nucleic acids and amino acids in proteins. As a result of this conceptual composition of the subject, our effort has had two components: (1) a study of the chemistry of activated aminoacyl species, and (2) 

an attempt to deduce correlations of poperties and selective affinities between 

amino acids and nucleotides. The chemical studies have shown that all of the reactions, from initial activation by ATP to peptide bond formation, are spontaneous. 

These studies have included activation of amino acids by ATP, transfer of amino 

acids from nucleotide anhydride to ester mediated by imidazole, and hydrolysis 

and attack by nucleophiles, including peptide formation. Data from our laboratory 

and others have shown that the genetic code is far from random, and reveal direct 

correlations of a number of properties between amino acids and their anticodonic 

nucleotides. Furthermore, by a variety of techniques, principally NMR, we have 

now begun a collection of binding constants between amino acids and nucleotides. 

These binding constants, though low (i.e. < 10 M-l), consistently show selective 

affinities between amino acids and their anticodonic nucleotides. For example, 

bindin constants of the amino acid, phe, 

6.6 M-Q (AMP) 

for the four common nucleotides are 

> 3.5 M-l (GMP) > 2.1 ~-1 (CMP) > 1.1 M-l (UMP). These data 

probably explain why the only anticodons of phe contain AAPu (3' + 5'). In addition, a number of studies have shown that, of the hydrophobic amino acids (phe, 

leu, ile, val, met) having "A" as the middle, most important anticodonic letter, 

phe has the greatest affinity for adenine derivatives. Studies of the reaction 

of this same set of amino acids with ATP haveshown that the rates of reaction 

are correlated with the affinity of the various amino acids for adenine derivatives. 

From these kinds of data, a general principle has emerged - namely, that the 

rates of various chemical reactions between amino acids and nucleotides are a 

function of the degree of affinity between the reacting species. Consequently, 

our present working hypothesis is that the genetic code and its attendant process 

of protein synthesis arose as a consequence of selective affinities between amino 

acids and their anticodonic nucleotides. 

6-5 
NUCLEIC ACID TEMPLATE PROPERTIES 

Robert Rein*and Thomas Kieber-Ermnons 

Roswell Park Memorial Institute 

Buffalo, NY 14263 

During the past few years progress has been made in the area 

of non-enzymatic synthesis of oligonucleotides in the presence of 

polynucleotide templates (Orgel and coworkers). Prominent among 

the factors influencing the effectiveness of these reactions are 

template composition, specificity of ions and the nature of 

activating groups. 

One of our aims is to explain in molecular terms why are 

polypyrimidines effective templates and polypurines not. 

Calculations of helical structure preferences depending on 

sequence will be presented. Since the prerequisite of template 

facilitated condensation is the formation of Watson-Crick, Wee 

helicies, the conformational preferences and stabilities of both 

the template and the single base stacks are paramount for the 

outcome of the reaction. Stabilization by specific ionic bridges 

may further influence the conformational choices. The presented 

data will illustrate the effect of these factors and show that 

template efficiency is a result of a subtle interplay between 

sequence dependent conformational stabilities and helix 

compatabilities .(2'-5' or 3'-5' linked nucleotides). 

Another interesting aspect 

sequence length distributions of 

stochastic model will be outlined 

chain length distribution of a svn 

first step of the prog ram conit 

mixed populati on of sing le and 01 

probab i .lities for elonga .tion of d 

interval are decided according 

isotherms. 

of 

the 

for 

the's 

ruct 

igon 

.iffe 

to 

these reactions is the 

formed oligonucleotides. A 

simulating the kinetic and 

izing oligonucleotide. The 

s binding isotherms for a 

ucleotides. The reaction 

rent species at each time 

the state of the binding 

In addition, energetics's of various base mispairs will be 

presented together with calculated mutation probabilities. The 

aim of this study is to estimate the frequency and type of 

mutations which could have occurred during the replication of 

prebiotic double helical oligonucleotides and polynucleotides. 

Finally, models of nucleotide-peptide complexes constructed 

from studies of present day protein-nucleic acid complexes will 

be presented and discussed. The emphasis will be on the 

examination of these complexes as possible structures involved in 

the origin of the coupling between the two informational 

macromolecules as well as the start of gene regulation. 

The significance of these studies should ,be in the potential 

usefulness for designing effective heteronucleotide templates 

in further prebiotic synthetic experiments. 

66 
The Influence of Water on the Stability of DNA Rase Pairs 

Andrew Pohorille* 

Stanley K. Rurt 

R. D. MacElroy 

NASA-AMES Research Center 

Moffett Field, California 94035 

One of the fundamental problems associated with the study of the 

origin of life is that of information storage and transfer. Those 

factors that affected the stability and polymerization of 

polynucleotides in pre- and proto-biotic environments would have 

dictated the kind of process that would emerge as functional in 

living organisms. Single stranded structures would not be as good 

as double stranded as candidates for primary information storage 

molecules because exposure of the nucleic acid bases to the solvent 

would increase susceptibility to chemical modification and 

mutation. Thus, in pre- and protobiotic systems, the double 

stranded structures that would be formed during replication would 

impart considerable stability to stored genetic information. While 

double' stranded nucleic acids are thermodynamically stable in an 

aqueous environment and do not dissociate readily into separate 

strands, they could not be so stable as to be unseparable at the 

time of replication in prebiotic systems that lacked the 

specialized enzymes of extant replication. This essential balance 

between stability and separability, is brought about by a delicate 

interplay between hydrophilic and hydrophobic effects, and is an 

important factor in the stability of the DNA helix in living 

systems today. 

It was assumed for some time that the stability of nucleic acid 

resulted exclusively from hydrogen bonding. Experimental data on 

isolated base pairs has cast doubt on this assumption. It has been 

established that in water, 

stacking interactions. 

isolated nucleic acid bases associate by 

In nonpolar solvents, however, base pairs 

do associate by hydrogen bonding. To investigate the basis of the 

stability of the DNA helix in aqueous solution we have performed 

Monte Carlo simulations of stacked and planar associations of the 

nucleic acid bases adenine and uracil in both polar (water) and 

nonpolar solvents (e.g. CC14). These simulations use mathematical 

models of molecular structures, various model representations of 

the forces that attract and repel the atoms of the molecules, and 

permit the exploration of the behavior of base or solvent molecules 

in realistic volumes, and at selected temperatures and pressures. 

Our results show that in a nonpolar environment planar association 

of A-U is favored bu 8 kcal/mole over stacked self-associations, 

while in aqueous solution the opposite is true. These results can 

be interpreted in terms of a balance between solute-solvent and 

solvent-solvent interactions and give us a unique insight into the 

role that electrostatic and dispersion forces play in polar and 

nonpolar solutions. 

67 
SESSION IV 

SOLAR SYSTEM EXPLORATION 

68 
NFW GC COLUMNS FOR INVESTIGATION OF THE ATMOSPHERES OF TITAN AND THE OUTER PLANETS 

Glenn E. Pollock*, Dan R. Kojiro and Fritz H. Woeller 

NASA-Ames Research Center 

Moffett Field, CA 94035 

The accurate measurement of atmospheric constituents of extraterrestrial bodies, 

planets, moons or comets, may provide more concrete information on which to 

base hypotheses about the origin and evolution of the solar system, chemical 

evolution and life. Previous missions to Mars and Venus measured atmospheric 

constituents by gas chromatography using state of the art technology. However, 

missions to bodies much more distant require that the instrumentation used on 

those flights be significantly reduced in power, weight and volume requirements 

and that sensitivity be increased. These factors have necessitated the 

miniaturization of many of the component parts of a gas chromatograph and that 

includes the development of new column technology to be compatible with the 

more sensitive detector system. 

Measurement of hydrocarbons in the atmospheres of target bodies is one major 

objective and since the conventional liquid hydrocarbon phases were unusable 

because of bleed, it was necessary to investigate chemically bonded materials 

using porous silica as a base. Various syntheses were carried out, taking 

advantage of the silanol groups available for derivatization. Amino silica was 

made and modified with other compounds in such a way that aromatic amides, urea, 

and Schiff base surfaces were made as well as directly derivatized silica which 

produces urethane surfaces. Columns which will separate the reported hydrocarbons on Titan have been made and are reasonably short (75 cm x 1 mm>, light, 

and analysis time is fast and, using the metastable ionization detector. sensitivity is at the ppb to sub ppb level. Further column development is continuing 

to develop and reduce in size, weight and volume, columns which will separate the 

permanent gases and more polar organics and water. 

69 
LIMITS i)F IN SITU DETECTION OF VOLATILES IN SOLAR SYSTEM EXPLORATION -- -- 

Fritz H. Woellerk, Daniel R. Kojiro and Glenn C. Carle 

NASA-Ames Research Center 

Moffett Field, CA 94035 

Measurements of volatiles associated with extraterrestrial bodies are an 

integral part of studies pertaining to biological compatibility, ecology, 

the chemical history of the solar system, and the origin and evolution of 

life. The confirmation and refinement of remote-sensing data on chemical 

composition through in situ analysis has become a reality with the .-- - 

successful Viking and Pioneer-Venus missions. The early designs of 

analyzers for volatile, or volatilizable, chemical species have been 

improved with the goal of reducing weight and power requirements, and 

increasing the sensitivity and resolution of the instruments. 

The sensitivity of gas chromatographs and parallel mass spectrometers used 

as flight instruments has reached comparable magnitude. The GC thermistor 

detectors deployed with the Viking and Pioneer-Venus missions are being 

replaced by ionization devices that are sensitive in actual situations to 

the parts-per-billion level and can be adjusted to register concentrations 

from that level upward over a large dynamic range. The new devices are of 

miniature dimensions, shock-resistant, reliable, and thermally and pneumatically stable. Specific response to all molecular species is non-selective 

and does not depend on chemical complexity. 

70 
ANALYSIS OF COMETARY DUST BY GAS CHROMATOGRAPHY 

Bonnie J. O'Hara* 

NASA-Ames Research Center 

Moffett Field, CA 94035 

Comets are primitive solar system bodies which release large quantities of 

gas and dust during their transit of the sun. Being very primitive, they 

contain information about the early history of the biogenic elements that 

may not be found anywhere else in the solar system. Specifically, 

information about the biogenic elements may be found in the volatile and 

nonvolatile molecules associated with the released comet dust. These 

molecules, many of which may be comprised of the biogenic elements, include 

surface absorbed, chemically bound and those internal to the stable host. 

Collecting comet dust and subsequently measuring the associated volatiles 

will therefore provide an understanding of the early history of the biogenic 

elements as related to chemical evolution. In future efforts to study these 

particles, both remotely and with a returned sample, only very small samples 

will be available. Therefore, a highly sensitive analytical instrument is 

needed to analyze the small quantities of volatiles released from the available 

cometary dust. The gas chromatograph is such an instrument. 

A laboratory prototype of a flight gas chromatographic system based on recent 

advances in the state-of-the-art has been assembled specifically to analyze 

volatiles associated with cometary dust. The dust samples are heated stepwise to pyrolysis temperatures and the released volatiles are then separated 

on a highly efficient gas chromatographic column and measured with a very 

sensitive detector. Model comet dust, such as carbonaceous chondrites, have 

been incrementally heated and the released volatiles measured. For example, 

from a Murray meteorite sample heated to 75O"C, Hz, N2, CO, NO, CH4 and CO2 

were evolved which were readily detected and measured. It is estimated that 

sub-microgram samples would allow measurement of volatiles in the ppm range 

if the particles resemble CM carbonaceous meteorites. 

71 
, . .-. . 

MULTIPLEX CHROMATOGRAPHY FOR SOLAR SYSTEM EXPLORATION 

Jose R. Valentin* and Glenn C. Carle 

NASA-Ames Research Center 

Moffett Field, CA 94035 

John B. Phillips 

Southern Illinois University 

Carbondale, IL 62902 

Determination of molecular species comprised of the biogenic elements in the 

atmospheres of planets and moons of the solar system is one of the foremost 

requirements of the exobiologist studying chemical evolution and the origin 

of life. Flight experiments have been conducted on both Mars and Venus in the 

past and a wealth of data has been acquired by the gas chromatograph, mass 

spectrometer and gas chromatograph/mass spectrometer. Future missions to 

explore Saturn, Titan, Mars and Venus will require advanced instrumentation 

concepts which are highly sensitive, efficient, physically small and capable 

of analyzing complex mixtures. Recent advances in gas chromatography suggest 

that conventional gas chromatography is still one of the most practical methods 

available to conduct the desired analyses in future constrained missions, but 

limitations in the technique still exist which can be alleviated with multiplex 

chromatography. 

Multiplex chromatography is a technique where many samples are psuedo-randomly 

introduced to the chromatograph without regard to elution of preceding 

components. The resulting data is then reduced using mathematical techniques 

such as cross-correlation or Fourier Transforms. Several advantages are 

derived from this technique. A signal to noise ratio increase of several 

orders of magnitude may be realized since all random noise may be effectively 

discarded. Further, because there is no need to wait for the last component 

of a analysis to elute before starting the subsequent analysis, many more 

analyses can be conducted in a given length of time. This would be particularly 

useful in an atmospheric probe mission where there is a discrete amount of time 

available for the mission. To demonstrate the capabilities of multiplex 

chromatography for future solar system exploration, a sampling system or 

chemical modulator has been developed which offers many advantages over 

previously reported mechanical samples or modulators. Samples under analysis 

are merely absorbed and desorbed from a small bed of selectively sorptive 

material thus eliminating all mechanical devices from the chromatograph. 

72 
SESSION V 

PLANETARY PROTECTION 

73 
PROPOSED NEW POLICY FOR PLANETARY PROTECTION 

D. L. DeVincenzi P. D. Stabekis* 

Life Sciences Division Exotech Research and Analysis, Inc. 

NASA Headquarters Gaithersburg, MD 

Washington, DC 

J. B. Barengoltz 

Jet Propulsion Laboratory 

Pasadena, CA 

In order to control contamination of planets by terrestrial 

microorganisms and organic constituents, U.S. planetary missions 

have been governed by a planetary protection (or planetary 

quarantine) policy which has changed little since 1972. This 

policy has recently been reviewed in light of new information 

obtained by planetary exploration during the past decade and 

because of changes to, or uncertainties in, some parameters used 

in the existing quantitative approach. On the basis of this 

analysis, a new planetary protection policy, with the following 

key features, is proposed: deemphasizing the use of mathematical models and quantitative analyses; establishing requirements 

for target planet/mission type (i.e., orbiter, lander, etc.) 

combinations; considering sample return missions a separate 

category; simplifying documentation; and imposing implementing 

procedures (i.e., trajectory biasing, cleanroom assembly, spacecraft sterilization, etc.) by exception if the planet/mission 

combination warrants such controls. Interpretation of the new 

policy for missions like Galileo, Mars Surface Sample Return, 

Saturn Orbiter with Twin Probes, and missions to comets are 

considered. In general, the new policy proposes elimination of 

all but documentation requirements for most planetary missions 

and simplification of the remaining compliance procedures. 

74 
._ i .__ . . . . . . . . . ,~ .._ --..--- . . . . -..-- --.-.. .._--..-..-_.-.__- -..... . .- ._ $=J 

:;j. 

?z 

SESSION VI 

FUTURE DIRECTIONS 

75 
The Biogenic Elements and their Compounds: 

The Astrophysical Context 

John A. Wodd* 

Harvard-Smithsonian Center for Astrophysics 

Cambridge, Massachusetts 

Abstract 

The chemical elements that served as raw materials for 

life-forming processes had a long and complex history prior to 

their presence in the terrestrial atmosphere. A NASA Study Group 

on the Cosmic History of the Biogenic Elements and Molecules has 

recently reviewed, our current understanding of the pre-planetary 

evolution of these materials. 

The biogenic elements (principally C,N,O,H) were formed by 

thermonuclear processes in the interiors of previous generations 

of stars, and expelled to the interstellar medium by stellar winds 

and supernova explosions as atoms, molecules, and condensed just 

particles. This inventory of materials was changed in the interstellar medium by photochemical and other types of reactions, prcducing (among other things) the array of organic molecules detected 

in space by radio and IR spectroscopy, and also possibly complex 

refractory polymers on grain surfaces. The system was further modified chemically during self-gravitative collapse of a volum? 0' 

the interstellar medium to become the protosun and solar nebula. 

and in the nebula as it evolved. Organic materials "ram the nebula 

were trapped in the planetesimals as they aggregated. and to varying 

degrees altered in them by thermal and hydrothermal metamorphism. 

Samples of primitive solar system organics at this stage of their 

evolution are preserved for our study in meteorites. 

76 
THE GALAPAGOS HYDROTHERMAL VENT ECOLOGIES: 

POSSIBILITIES FOR NEOABIOGENESIS? 

Cyril Ponnamperuma and Mitchell Hobish* 

Laboratory of Chemical Evolution 

Department of Chemistry 

University of Maryland 

College Park, MD 20742 

Recent discoveries of complex ecologies at hydrothermal 

vents on the ocean floor have opened up new areas for research 

into the origins of life on Earth and the evolution of corrununities 

of micro-organisms under extreme environmental conditions. Under 

such conditions, the question of neoabiogenesis appears to be a 

tantalizing possibility. 

In order to explore these opportunities, the Laboratory of 

Chemical Evolution of the University of Maryland organized a 

workshop at the Belmont Conference Center, Elkridge, Maryland on 

April 22-24, 1982. A group of scientists familiar with the phenomena 

of the vents, and selected from the fields of biology, chemistry, and 

geology, presented the data available on the characteristics of 

this unusual environment. 

Enormous fluxes of solvent and solute reslnt in the formation 

of gradients of pH, temperature, and concentration of chemical 

species. The vents are capable of sustaining populations of 

micro-organisms of thermophiles, mesophiles, ana.erobes, chemoautotrophs, 

etc. The rich "organic broth" seems to serve as an excellent source 

of food for the megafauna. It is generally believed that all the 

conditions suitable for the origin of life have.disappeared from 

the earth. Perhaps such conditions are found today providing the 

opportunity for investigating the concept of neoabiogenesis. 

77 
THE EVOLUTION OF COMPLEX AND HIGHER ORGANISMS 

David Raup* 

Field Museum, Chicago 

and 

John Billingham 

NASA-Ames Research Center 

The existing NASA Planetary Biology Program has dealt with chemical 

evolution and the origin and early evolution of life, but has not examined 

events after the late Precambrian. To explore the possibility of filling 

out the program to cover the Phanerozoic, a group of scientists met in a 

series of science workshops over the past year to examine the major questions 

involved. 

We made the following assumptions: (1) The starting point, in the 

evolutionary sequence, would be the appearance of multicellular organisms, 

some one billion years ago; (2) All phases of the evolution of complex 

life would be addressed, up to and including primates; (3) Special attention 

would be given to the interaction between the evolving biota and the physical 

and chemical characteristics of the environment; (4) Special emphasis would 

be placed on evolutionary changes which might be related to events in space, 

namely astrophysical phenomena, solar disturbances, earth moon interactions, 

solar system dynamics and asteroid and cometary impacts; (5) Attention would 

also be given to the study of the possibilities for the existence of complex 

life elsewhere in space. 

The draft of our report is now in preparation. Each chapter deals with 

current views and gives recommendations for research areas of importance. 

The chapters deal with the following topics: (1) The geologic history of 

complex organisms; (2) Physico-chemical environments; (3) The evolutionary 

process; (4) The effects of extraterrestrial phenomena; (5) The potential 

for complex life elsewhere in space. 

The report will go to press in November 1982, and should be published 

in May 1983. 

78 
ROLE OF EXOBIOLOGICAL SCIENCE 

IN THE FUTURE OF SOLAR SYSTEM EXPLORATION 

3. (Ire* 

University of Houston 

Houston, Texas 77004 

A rational approach to the space exploration of the solar system has to include 

all the aspects of physical, chemical and biological science which are relevant 

to such an exploration. We need to know not only the compositional, structural, 

and dynamical aspects of the present solar system, but also how it was formed 

from interstellar matter and how did life originate in our planetary system. Two 

fundamental principles which have emerged as the result of exobiological research 

performed during the past two decades are the following: A. The origin and evolution of life where it occurs, is probably an integral part of the physical and 

chemical processes that go into the formation and evolution of the planets. B. 

Once life has originated on a planet (Earth) its presence causes major changes 

in the partsof the planet which interact with the biosphere. From then on the 

physical evolution of the surface, hydrosphere, and atmosphere of the planet is 

significantly influenced by life. Therefore, we need a comprehensive understanding of the general process of planetary evolution which has culminated in 

the emergence of life in at least one case, and the impact of this life in the 

future evolution of the planet. More specifically, the three major questions that 

have to be answered to provide this understanding are: 1. What can the study of 

extraterrestrial organic chemistry tell us about the prebiological chemical era 

on Earth and elsewhere? 2. How did the formation and earliest history of the 

Earth set the stage for chemical and early biological evolution?, and 3. Once 

life has emerged, what is the impact of the evolution of life on the Earth's 

planetary evolution? 

Both terrestrial and extraterrestrial investigations are required to answer 

these questions. In approximate order of priority the primary targets for solar 

system exploration of interest to exobiological science can be divided into three 

major groups: (a) Small primitive bodies, namely comets, asteroids, meteorites, 

and interplanetary dust. (b) Giant planets and their satellites, with special 

emphasis on Titan and Europa. (c) Terrestrial planets and their satellites, essentially Mars, Phobos, neimos, Venus and the Moon. Beyond the solar system some of 

the comparable primary targets are: (d) Circumstellar and interstellar clouds, 

(e) Dense and gravitationally contracting nebulae, as analogs of our primeval 

solar nebula, and (f) Non-luminous bodies orbiting other solar-like stars, as 

analogs of planets in our solar system. In this case both ground-based and or 

bital telescopes can be used to make measurements of exobiological relevance by 

means of visible, IR., or microwave spectroscopy. With the information obtained 

from the above targets we may be able to answer the first question (1 above). To 

provide answers for the second and third question (2 and 3 above) will require 

an in depth study of the Earth by comparative planetology and by direct observation, in situ, or from orbital spacecraft. It is well understood that a complete understanding of the origin and evolution of life on the Earth will not be 

possible without parallel studies in terrestrial laboratories providing the 

necessary experimental support to the above exobiological exploration of the 

solar system and beyond. There appears to be a general consensus on this approach 

among the scientific community as indicated by the recent report "Extraterrestrial 

Exploration and the Origin of Life", edited by R. S. Young. A more detailed discussion of the priority targets of interest to exobiological science will be 

presented. 

79 
The Status of SET1 Research 

Frank D. Drake* 

National Astronomy and Ionosphere Center 

Cornell University 

Detailed studies of the SET1 problem have been made over the last 

few years by the ad hoc "SET1 Science Working Group" (SWG) established with 

NASA sponsorship. These studies have reconfirmed the idea that the most 

promising approach to the detection of other civilizations or, indeed, perhaps 

extraterrestrial life, is through a search for microwave radio transmissions. 

The most important need is the ability to search large portions of the radio 

spectrum with good radio frequency resolution. New low-cost integrated 

circuit chips have solved this problem, and a design and appropriate prototypes exist for the construction of a multi-channel spectrum analyzer (MCSA) 

of reasonable cost. It would provide coverage of over 8 million channels 

simultaneously, and would be utilized with dedicated computers and appropriate 

software to conduct an automatic, generalized search of the energy collected 

by a radio telescope for evidence of signals of intelligent origin. As 

planned by the SWG, the MCSA would be used with existing large radio telescopes 

to search the entire visible sky over a wide range of frequencies for strong 

signals, and a large number of directions of special interest, such as the 

direction to near-by sun-like stars with greater sensitivity. This 

would increase the parameter space searched for signals by a factor 

roughly a million over the space searched in all previous attempts. 

In the meantime, a much smaller version of the MCSA, funded pr 

program 

of 

ivate lY9 

has been used in a search which tests many of the concepts in the NASA plan. 

In the USSR a number of large SET1 programs are underway. One program involves 

the construction of some one hundred small antennas specifically to give good 

sky coverage for SETI, and another is associated with a new high precision 

TO-meter telescope now under construction near Samarkand. 

80 
SESSION VII 

GEOLOGICAL RECORD 

81 
ASPECTS OF EVOLUTION AND DIVERSITY OF PRECAMBRIAN LIFE: ARCHEAN AND PROTEROZOIC 

Elso S. Barghoor#and Paul K. Strother 

Harvard University, Cambridge, MA 02138 

It is perhaps fair to say that the study of the origin and evolution of Precambrian 

life is paradoxically both frustrating and highly rewarding. It is frustrating in 

that much of this immense period of earth history provides only a fragmented though 

highly significant record of ancient life. The sedimentary-metamorphic history of 

the solid earth has recently been extended back to ca. 3.8 b.y. in the Isua supracrustals of Greenland; the credible morphological record of life extends back to ca. 

3.4-3.5 in the Swaziland Sequence of South Africa and possibly in sediments of the 

Pilbara Block of Western Australia. The study of Precambrian paleobiology is rewarding in that the known tangible record conforms to a logical theoretical model 

of evolution from isolated single-celled organisms through stages of colonial to 

multicellular organisms to the evolution of distinct microbial ecosystems by late 

Precambrian time. 

If we eliminate the alleged "fossils" from the Isua metasediments as of abiotic and 

indeed purely mineralogical origin, the earliest discrete entities which may be considered truly biological are the carbonaceous microspheres from the early Precambrian upper Onverwacht sediments of South Africa. The evidence is based on both 

morphology, their presence in aggregates of organic clasts, and in their size-frequency distribution patterns of which closely resemble those of steady-state populations of extant algal unicells. Also, certain of the microstructures have been 

preserved in the configuration of binary cell division. The ratios of the stable 

isotopes of carbon "C and 12C (6 13C) of their organic matter and its matrix are 

also consistent with their biogenic origin (6 13C = -25 to -30). 

A major "benchmark" of the level of early Precambrian microbial evolution is abundantly 

represented in the ca. 2 b.y. old Gunflint iron formation, Lake Superior region. 

At least 16 taxa of microfossils, some of questionable affinity with any known extant 

organisms, can be recognized. These represent a wide range of morphological diversity within the realm of prokaryotic life. None of them can be regarded as of unquestionable eukaryotic origin, on the basis of either size or histology. The more 

significant elements of the Gunflint microbiota will be discussed. Significant microbiotas of essentially Gunflint age recently have been described from the Belcher 

Islands, Hudson Bay, Canada, and the Duck Creek basin of Western Australia. The wide 

geographic spread of now known microfossil assemblage of about 2. b.y. age are putative evidence of a world-wide thriving biosphere by mid-Precambrian time. 

As we proceed upward in Proterozoic sequences in various geographic areas of the 

earth the number of microbial occurrences on the existing continents increases. 

Among the richest and most diverse of these are the Bitter Springs Formation of 

central Australia (ca. 800 - 900 m-y.), and a recently discovered and yet unpublished 

biota from the Narssaessuk Formation of northwest Greenland. These show increasingly 

more complex morphology. Of the late Precambrian assemblages, one, though not 

taxonomicall 

it 

rich possesses members of the biota such as acritarchs and large unicells of sue size 080. -1OOu) that they provide evidence of eukaryotic affinity. 

Crucial evidence for the time of emergence of unquestionable eukaryotic life would 

be the discovery of reproductive organs or sexual reproductive stages, a circumstance well within the realm of possibility in view of the remarkable preservation 

now known in Precambrian sediments. 

82 
ARCHAEAN STROMATOLITES FROM ZIMBABWE: EVIDENCE FOR ENVIRONMENTAL CONDITIONS 

Paul I. Abell* 

Joseph McCl ory 

University of Rhode Island 

Kingston, Rhode Island 

Euan Nisbet 

University of Saskatchewan 

Saskatoon, Canada 

Anthony Martin 

University of Zimbabwe 

Salisbury, Zimbabwe 

The only direct evidence we have for life in the Archaean is the occurrence of algal stromatolites. To the extent that they can give us clues 

as to their growth environment, we gain knowledge of the general environmental conditions of the Archaean. Unfortunately, most stromatolites of 

that age have been subjected to some degree of alteration, which clouds the 

picture. Some of the best preserved stromatolites of Archaean age are to 

be found in Zimbabwe, in the Cheshire, Manjeri and Mushandike formations. 

Cores from these algal limestones have been examined in some detail using a 

variety of analyses, including stable isotope ratios of carbon and oxygen, 

various inorganic elemental analyses, and the petrology by thin sections. 

Thirty cores were obtained from the three formations durin 

of 1981. The various domains of carbonate were examined for 61 0, B C and ii! thel !Pmrner 

Fe, Mgi8Mn, Sr and Rb. The Cheshire and ManJeri formations (age 2.7 b.y.) 

show 6 0 values of -8 to -13%0 (PDB) and 61 C values for kerogen of -26 to 

-35%0 (PDB). The magnesium content is low, seldom exceeding 2%, even in the 

most dolomitized areas. Rubidium concentrations run about 50 ppm, while 

strontium is quite variable. Rubidium-strontium isochrons are being attempted. There is a substantial quantity of minera.l-bound water in these 

algal limestones, and D/H ratios in the fraction of water released at about 

550" is being examined. 

In thin- section, textural preservation is often excellent, although 

some early recrystallization is commonly seen. The best preserved Cheshire 

samples show a wide variety of primary structures, and there is no evidence for 

the pervasive passage of post-lithification fluids through the rocks. Some 

preserved algal structures seem to be present. 

It has been a disappointment that the cyclical nature of the Cheshire 

formation (22 cycles in the 50 meters of thickness) does not show up in any 

significant variations in oxygen isotope content. Minor changes are clearly 

evident in the elemental analyses, however. 

The evidence from the thin sections for a closed system, and the negative 

values of the oxygen isotope ratios argue for an ocean temperature near 5O"C, 

but further work is necessary before this can be defended with any certainty. 

83 
GEOCHEMISTRY OF CARBON IN THE LOWER CRUST AND THE HISTORY 

OF THE CARBON CYCLE ON EARTH 

DAVID DES MARAIS* 

AMES RESEARCH CENTER 

MOFFETT FIELD, CA 94035 

Studies of ancient iife are severely constrained by our limited knowledge 

of the earliest terrestrial environment. This environment was influenced, 

perhaps profoundly, by volatiles emanating from the earth's interior. 

This presentation discusses the nature of carbon in present-day emanations 

and attempts to interpret its significance for studies of ancient life. 

Today, most "juvenile", deep crustal carbon emanates from the vast midoceanic ridge system. The present rate of carbon emanation would require 

more than three times the age of the earth to accumulate the present 

inventory of sedimentary carbon. Within the uncertainty of the measurements, the average carbon isotopic composition of the total sedimentary 

reservoir is identical to that of the juvenile carbon, which occurs both 

in midoceanic basalts and in the hydrothermal fluid. This similarity 

indicates that the average carbon isotopic composition of the earth's 

sedimentary reservoir has been remarkably constant over geologic time. 

Concerning the chemical state of juvenile carbon, several measurements 

of carbon dioxide and hydrocarbons have been made in geothermal localities. 

Molecular carbon isotopic data indicate that most, if not all, of the 

hydrocarbons contributed by continental geothermal systems derive from 

thermal decomposition of organic matter in sedimentary rocks or groundwater. The origin of the methane which emanates from marine hydrothermal systems is still uncertain. 

84 
THE OXYGEN ISOTOPIC RECORD IN PRECAMBRIAN KEROGENS 

J. M. Hayes and Kim W. Wedekinp 

Biogeochemical Laboratories, Departments of Chemistry and of Geology 

Indiana University, Bloomington, Indiana 47405 

Research in our laboratories comes under the heading of "isotopic 

biogeochemistry." Specific investigations range from studies of the enzymatic 

control of the distribution of carbon-13 within biosynthetic products [Monson 

and Hayes, JBC 255, 11435 (1980); GCA 46, 139 (1982); JBC 257, 5568 (1982)] 

to isotopic stuzs of Precambrian kerzens [Hayes, et al.,n press]. All -- of these studies are aimed at reconstructing the record of biochemical 

evolution. On the one hand, the study of isotopic fractionations characteristic 

of modern systems provides baseline information about the isotopic signatures 

of specific environments and biological processes. Further, study of the 

Phanerozoic geochemical record allows recognition of post-depositional 

alteration processes that can affect isotopic signals initially carried by the 

biological input. On the other hand, isotopic studies of ancient kerogens, 

when combined with this baseline information, can help to define the timing 

of major events in biochemical evolution. For example, the record of carbon-13 

abundances in Precambrian kerogens has been interpreted in terms of the origin 

of autotrophic carbon fixation prior to 3.5 Ga ago; the origins of methanogenesis, oxygenic photosynthesis, and methylotrophy prior to 2.7 Ga ago; and 

the gradual rise of multicellular organisms in the interval between 2.0 

and 0.8 Ga ago. 

The record of oxygen isotopic abundances in sedimentary organic matter 

is completely unexplored, primarily because of analytical difficulties (methods 

for the quantitative conversion of organic oxygen to CO2 have been lacking 

until very recently). Now, however, we have adapted the methods developed 

by others [Thompson and Gray (1977), Brenninkmeijer and Mook (1980)] for the 

analysis of pure cellulose to the analysis of oxygen-18 both in pure compounds 

and in the more complex organic materials found in geological specimens. 

Following on this development, study of oxygen isotope ratios is now underway 

in (i) Precambrian kerogens, (ii) re p resentative suites of Phanerozoic materials, 

and (iii) specimens subjected to laboratory isotope-exchange experiments aimed 

at exploring the possible lability of organic oxygen in sediments. These analyses 

will provide data allowing a systematic evaluation of the significance and 

preservation of biologically controlled oxygen-18 abundances in both recent 

and ancient kerogens. Thus far, it seems evident that the oxygen isotopic 

composition of sedimentary organic materials can be related to (a) the 

isotopic composition of the water available to the organisms and (b) some 

aspects of the metabolism of the organisms. 

85 
r’ .- ’ -. ..-.---. - ._ _ ,.,,..,., ..- .m-. ..---- .---.. - .- ..- --.-. 

r ” 

ALTERATION PAWS OF SEDIMZNTARY ROCK ORGANIC H4TER WRING BURIAL 

I.R. Kaplan* 

Institute of Geophysics and Planetry Physics 

University of California 

Ins Angeles, California 90024 

Precambrian sediments are occasionally rich in carbonaceous material. 

Many excellent examples of well-preserved, carbon-rich shales and cherts dating 

back to over 3.6 g.a. have been studied in South Africa and Australia. 

Recognizable morphological remains of procaryotes have been found in numerous 

outcrops. Unfortunately, the nature of the chemical remains in the 

carbonaceous material does not permit a definitive characterization of this 

material to be performed. The objectives of the research being undertaken are 

(1) to study the pattern of catagenesis resulting from the burial of organic 

matter in the stratigraphic column over geologic time and (2) to devise 

recognition patterns which could help differentiate residual carbon compounds 

which were originally synthesized biologically fran those which have been 

synthesized abiologically during the early history of the earth. 

The majority of the studies have been performed by taking recent 

sediments, drying them and subjecting either the ent$.,re sediment or the 

extracted proto-kerogen to temperature regimes from 60-500 C over a period of 1 

to 15,000 hours (625 days), in closed Pyrex vessels. Other studies have been 

performed by mixing the separated proto-kerogen with defined minerals, to 

evaluate the role of inorganic substances in the preservation of organic carbon 

canpounds. fiasurements of Proterozoic and Phanerozic carbonaceous sediments 

have also been conducted. Volatile, extractable and non-extractable 

carbon-containing compounds have been separated and characterized. The pattern 

of gaseous and lipid-extractable material that form in the laboratory 

experiments is essentially identical to that found in Phanerozoic sediments, 

eqecially those that contain petroleum. The data clearly show that complex 

biopolymers will alter to geartonomers as well as geopolymers. The role of the 

mineral matrix is complex. Some minerals are catalytic in the alteration of 

the original organic matter whereas others are inhibitory. The data further 

show that the kinetics of organic degradation may not follow a simple first 

order Arrhenius model. The character of the residual kerogen can be determined 

by X-ray diffraction and elemental measurements. Isotopic ratio measurements 

of the kerogen can help to identify a biological component of the kerogen. 

8 6. 
THE IMPORTANCE OF METAL COMPLEXED AMINO ACIDS IN GEOCHRONOLOGY OF 

FOSSILS AND TO THE ORIGIN OF CHIRALITY 

Grant Gill Smith* 

Utah State University 

Logan, Utah 84322 

There is a unique relationship between optical activity and life. 

Virtually all proteins contain exclusively the L-enantiomer of the amino 

acid. These same amino acids are found in fossil shells and bones and once 

removed from the biosphere and reside in the geosphere, they slowly change 

to their mirror image, the D-enantiomer(racemization). From the D/L ratio 

age estimates can be made of fossil material. There is no generally 

accepted theory for the origin of optical asymmetry though several theories 

have been proposed. 

The loss of optical activity to a mixture of D- and L-isomers is easier to 

study and progress is being made in the understanding of this aspect of 

diagenesis. Because amino acid racemization is a chemical reaction, it is 

affected by temperature, the chemical state of the amino acid (free or 

bound in peptides or proteins), the presence or absence of water, and metal 

ions (particularly transition state metals), the pH of the environment and 

the presence of bases and acids other than the conjugate base or acid of 

water. Competing reactions (e.g. hydrolysis, deamination, oxidation, etc.) 

play an important role as well. There is some evidence that even 

different species show different rates of racemization of amino acids (at 

least with shells) although this appears not to be the case with animal 

bones. 

In determining the age of fossils by this method, it is criti-cal that 

factors affecting the rate of racemization be very well understood and 

appreciated. Unfortunately this has not always been followed. It is now 

realized that without water, no significant racemization occurs with free 

amino acids, dipeptides, albumin or bone collagen. Unless hydrolysis of 

peptide bonds occur with proteins little or no racemization occurs. It is 

understood now why amino acid bound in peptides are the fastest to 

racemize. It is not the formation of a diketopiperazine intermediate as 

some have claimed, but rather the result of an intramolecular base effect. 

Transition state metals, when complexed to the amino acid, show marked 

influences on racemization. We have recently shown that Ni (II) retards 

racemization while Co(III), Cr(III), Pt(II), Pd(II) and Cu(II) enhance 

racemization. Deuterium exchange with amino acids complexed to Co(II1) 

occurs 6.6 times faster than racemization. Different diastereomers 

racemize at different rates, e.g. 

times faster than the 

A-trans [ Co(L-ala)31 racemizes 4.6 

A -cis isomer. 

126 times faster than free ala. 

ECo(III)(ala)3 1 complex racemizes 

There is some indication that the complex 

[Ni(D-ala)2 1 is less water soluble than [Ni(L-ala)2 1 which has 

important implications to enriching the "primordial soup" with the L-amino 

acid. Nickel was in rich concentration in the earth's crust during the 

early formation of life on earth. 

87 
THX ORIGIR AD SVC&UTIOfi OF I?JCROBIAL 3XDOLITH.S 

Susan E. Campbell and Stjepko Golubic* 

Department of Biology, Boston University 

'Boston, Massachusetts 02215 

Microbial endoliths are microscopic prokaryotes and eukaryotes 

which share the common property of penetrating hard carbonate 

substrates by chemical dissolution. In so doing, they leave 

specific traces of their activity as boreholes whose morphology 

conforms closely to that of the organism. Such endolithic trace 

fossils are known to occur in rock and skeletal fragments throughout the Fhanerozoic. Prior to the start of our research program 

the oldest known endoliths were Ordovician in age. We have begun 

a search for the earliest occurrence and evolutionary development 

of the endolithic habit. Petrographic thin sections of Cambrian 

and Precambrian rock are searched with high resolution light 

microscopy and photographed. Certain substrates are cast in 

plastic, the rock dissolved, and the borehole replicas studied 

by scanning electron microscopy. We are thus engaged in the 

discovery of new life forms in the Earth's early history. We 

relate them to the most comparable Phanerozoic and modern taxa 

on the basis of morphological and sedimentological evidence, 

determine their paleoecological relationships, and estimate their 

impact on the early global cycling of carbon. 

Frecambrian endoliths were discovered (by S.E. Campbell) in 

silicified ooids of the Eleonore Bay Formation, eastern Greenland 

(570-700 x 106 yrs). They are most comparable in size and morphology to modern endolithic blue-greens of the genus H ella (cyan07 

bacteria), a common borer of modern ooids, and posse '&37eistocene and Cambrian ooids as well. Thus it was determined that the 

origin of microbial endoliths predates the appearance of the 

skeletal bearing metazoans in the fossil record. We have also 

found endoliths within lower Cambrian ooids (Sardegna) which 

retained their carbonate mineralogy. It is therefore possible 

that older (Frecambrian) carbonate rocksmey still bear traces of 

endolith activity. The oldest known endolith body fossils were 

Silurian prior to the discovery of silicified Cambrian brachiopod 

shell containing boreholes and organisms (by 8. Awramik, consulting geologist). Work (by S. Golubic) on modern stromatolites of 

Shark Bay, Australia showed that lithification of Entophysalis 

stromatolites is essentially a seasonal phenomenon. The stromatolite building microflora is partly to completely destroyed by 

carbonate precipitating within their extracellular envelopes. The 

newly hardened surface is then colonized and bored by endoliths. 

Recolonization by zntophysalis mat starts another cycle. kssuming that this is a valid model for the growth of Precambrian 

Eoentophysalis stromatolites it now appears that these silicified 

microfossils comprised residual pockets of organisms that escaped 

obliteration by lithification during the same season of their 

genesis, rather than by later diagenetic alteration. If so, 

any Precambrian endoliths present had a similar preservation 

potential. Continuing research will address this problem, as well 

as the question: how old are the oldest endoliths? 

88 
ORGANIC CHEMICAL GRADIENTS IN LAMINATED CYANOBACTERIAL MATS 

FROM SOLAR LAEE, ISRAEL 

A.L. Burlingame* 

University of California 

San Francisco, CA 

In the shallow water zone of Solar Lake, a continuous sequence of laminated 

cyanobacterial mats about 80 cm. thick is present. The oldest mats date 

from 2500 yrs b.p. 

The ORGAST project members have concentrated their initial research on 

a few top mat sections (P-3, 3-10, lo-20 mm), a sample from the black 

sulfide reduction zone and several samples from the green colored 

older mats. Data were obtained about pyrolysis characteristics, carbohydrate components, several classes of lipids, carotenoid pigments, and 

ether and ester bound lipid moieties. Steep gradients were observed in 

the top mat sections. Some of these results and additional information 

on these sections will be presented. The major topic presented will be 

the further characterization of the gradients in the top mat. 

A more detailed sectioning of the upper 20 mm of the algal mat resulted 

in 12 layers which were characterized by light and electron microscopy 

and also subjected to chemical analysis. The layers were analyzed by 

pyrolysis mass spectrometry and pyrolysis gas-liquid chromatography/mass 

spectrometry (EI and CI modes) to evaluate gradients in biopolymers such 

as proteins, peptidoglycane, storage carbohydrates and sheath material. 

Lipid class profiles were obtained by capillary gas-liquid chromatography/ 

mass spectrometry of total base hydrolyzable lipid fractions analyzed as 

mixtures of hydrocarbons, ketones, methyl esters and acetates with aliphatic, 

steroid and triterpenoid carbon skeletons. 

The results will be discussed in reference to the microbial ecology of 

the mats. Possibilities for extrapolation to other cyanobacterial mat 

systems and to fossil algal mat sequences will be evaluated. 

89 
GEOCHEMICAL ANOMALIES NEAR THE CRETACEOUS-TERTIARY, 

EOCENE-OLIGOCENE AND PERMIAN-TRIASSIC BOUNDARIES 

F. Asaro* , L.W. Alvarez 192 

, W. Alvarez3 and H.V. Michel' 

1) Lawrence Berkeley Laboratory, University of California 

2) Space Sciences Laboratory, University of California at Berkeley 

3) Department of Geology and Geophysics, University of California at 

Berkeley 

As an explanation of an iridium anomaly found initially in sediments near Gubbio, Italy, it had been hypothesized that an asteroid or 

other large-body extraterrestrial impact might be linked to the 

Cretaceous-Tertiary (C-T) mass extinctions of life about 65 million 

years (m.y.) ago. The purpose of the present program is to critically 

test if that iridium anomaly did result from a bolide impact (and the 

character of such a bolide), if such an impact can be definitely linked 

to mass extinctions, if bolide-related mass extinctions were repetitive, 

and if bolide impacts have been responsible for major shifts in the evolution of life. 

The C-T Ir anomaly has been found world-wide in about 37 different 

sites, 25 by our group and 12 by five other laboratories. Platinum, Au 

and Ir ratios in a bulk sample of the Danish C-T boundary agree exactly 

with values of CI chondrites (within the 6% measurement uncertainties of 

the latter) and are much different than the ratios usually obtained for 

terrestrial materials. X-ray diffraction and oxygen isotopic ratio 

measurements by M. Kastner have shown respectively that C-T boundary 

clays in Denmark and a core from DSDP Hole 465A in the Pacific Ocean 

were authigenic in contrast to clays above and below the boundary which 

were detrital. The world-wide distribution of the Ir anomaly, the 

exactly chondritic ratios of other noble elements associated with the Ir 

and the authigenic nature of the boundary clay strongly confirm an 

impact of a large extraterrestrial object as the source of the Ir. In 

our studies of 26 marine C-T sections an Ir anomaly was always found 

within 10 (and usually within 2) cm of the stratigraphic position (or 

center of the range) where paleontologists or geologists independently 

identified the C-T boundary. No significant Ir anomaly was found elsewhere except near the Eocene-Oligocene boundary. Thus the link between 

extinctions in the marine realm, particularly of plankton, is confirmed. 

Intensive studies in the continental realm are in progress. A second Ir 

horizon, associated with microtektites (about 34 m.y. old) and some 

(but not mass) extinctions, has been observed in three deep-sea-core 

sections (two by our group) of the Late Eocene epoch. Further intensive 

studies are in progress of many other sections from this time horizon. 

A study of the Permian-Triassic boundary (about 215 m.y. old) in China 

shows an authigenic layer with unusual abundances of many elements but 

with Ir < .055 ppb. Although it is most likely that such a layer has a 

volcanic origin, the possibility that it could arise as the result of a 

high-speed-comet impact is being investigated. Studies are being made 

of Ir and other element abundances in Pre-Cambrian sections (3.77 billion years old) to determine or obtain a limit in the average rate of 

meteoritic bombardment at that time. 

90 
ISESSION VIII 

EARLY BIOLOGICAL EVOLUTION 

91 
MICROBIAL MATS AND EARLY EVOLUTION 

Lynn Margulidaand John F. Stolz 

Department of Biology 

Boston University 

Boston, MA 0221 

Many paleontological studies including those comparing ancient stromatolites 

with modern microbial mats and stromatolites suggest that surface sedimentary 

deposition since the early Archean has been modulated by microorganisms. 

Since 1977 we have been studying laminated microbial communities that form 

desiccation polygons in a lagoonal complex north of San Qunitin at Baja 

California de1 Norte Mexico. The communities contain both oxygenic and 

nonoxygenic photosynthetic microbes and are a source of emission of reduced 

trace gases to the atmosphere. Fine structure studies of the in situ com- -- 

munity coupled with laboratory isolations have revealed a wealth of bacteria 

and a few protists in intimate association with sediment particles and protokerogen. Remarkable bacterial associations, such as bacteria-inside-abacterium and well developed sheath communities suggest that bacterial interactions of the sort hypothesized to be relevant to the origin of eukaryotic 

cells have been observed. This continuing research, the goal of which is.cthe 

reconstruction of the major evolutionary trends in the early history of life, 

includes as complete as possible a description of the organismal and mineral 

components of this microbial mat. 

The influx of terrigenous sediment and fresh water during the floods of 1979 

and 1980 altered profoundly the biotic composition of the mat but did not 

destroy its laminated fabric. Light and electron microscopic observations 

as well as field studies before, during and after the large floods will 

eventually permit the assessment of the preservability of such structures 

as well as their relationship, if any, to ancient laminated carbon-rich 

cherts and stromatolites. 

92 
Evolutionary Relationships in the Microbial World 

George E. Fox* 

University of Houston 

Houston, Texas 77004 

and 

Carl R. Woese 

University of Illinois 

Urbana, Ill. 61801 

Two special concerns of studies in planetary biology are the 

processes behind the origin and evolution of life and the effects 

of these same processes on the terrestrial environment. Integral 

to these goals is the long-standing need to determine the relative evolutionary position of the various microorganisms. Such a 

natural history can provide a background of biological facts 

against which one can evaluate proposals concerning the position 

in geological time of such key evolutionary events as the 

emergence of photosynthesis, the development of aerobic metabolism, etc. Macromolecular sequence data from ribosomal nucleic 

acid molecules is a powerful tool for deducing the required evolutionary relationships. It is a bonus that the same data can 

also be used to study the structure of the ribosomal RNAs. 

Understanding the constraints that govern the evolution of new 

structures in nucleic acid molecules is likely to be essential in 

bridging the gap in our knowledge which separates the processes 

of chemical evolution from the emergence of the first true 

organisms. 

Considerable progress has been made. This includes: (1) 

development of efficient procedures for sequencing 5s rRNA and 

the use of these procedures to determine seventeen new sequences; 

(2) the elucidation of universal secondary structural features 

in eucaryotic 5s rRNA; (3) the discovery that archaebacterial 5s 

rRNAs exhibit a variety of secondary stuctures that are distinct 

from those that are characteristic of eubacteria or eucaryotes; 

(4) the discovery of an unusual 5s rRNA that contains a 108 

nucleotide insertion in its interior; (5) development of(;; 

automated system for analysis of 16s rRNA catalog data; 

generation of summary dendrograms from over 200 bacterial strains 

that gave the first experimentally-based overview of bacterial 

evolution; and (7) completion of a Monte Carlo simulation system 

that promises to provide further insight in interpeting the 16s 

rRNA data. 

Major phylogenetic conclusions of the RNA work to date include 

!A!ed the aerobes 

confirmation of the long held view that anaerobic genera pre- 

; (2) the discovery that the photosynthetic 

phenotype is quite old; (3) the finding that the mycoplasmas are 

related to a specific subgroup of Clostridia and hence unlikely 

to be of great significance in early evolution; (4) confirmation 

of the endosymbiotic hypothesis as it pertains to chloroplasts 

and most importantly; (5) the demonstration of a fundamental 

dichotomy in the bacterial world that divides it into two classes 

of procaryotic entities, the eubacteria and the archaebacteria. 

93 
MOLECULAR EVOLUTION AND STUDIES ON METHANOBACTERIVM FORMICICVM 

John Bush, Richard Holmquist*and Thomas Jukes 

Space Sciences Laboratory 

University of California, Berkeley 

Berkeley, California 94720 

The goal of our research program is two-fold: 1) the study of the archaebacterium 

Methanobacterium formicicwn and 2) the development of improved techniques for the 

evolutionary analysis of nucleic acid sequences from extant organisms. With respect 

to the latter, natural selection for biological function and the nature of the genetic code have resulted in experimental1 y measurable constraints on gene and messenger 

RNA structures. Methods for using these measured constraints to extract evolutionary 

information from pairs of homologous genes will be discussed. The archaebacterial 

hypothesis states that there exists a major group of organisms which represent an 

ancient line of evolutionary descent distinct from the eukaryotes and prokaryotes, 

but sharing certain characteristics with each of the latter two kingdoms. Based on 

differences in 16s ribosomal RNA sequences, tRNA structure, cell wall composition 

and the chemical nature of membrane lipids, the archaebacteria are thought to include 

methanogenic bacteria, extreme halophiles and extreme thermoacidophiles. Our objective is to test this hypothesis by examining gene fragments of the archaebacterium 

Methanobacterium formicicwn. 

The evolution of the genetic code has been clarified by the discovery of amino acid 

codes in mitochondria that differ from the universal (nonmitochondrial) code. Mitochondrial codes use U in the first position of several anticodons to pair with U, C, 

A and G in codons. Starting from this primitive coding system a scheme is suggested 

which explains simply how the code could have evolved from 16 anticodons for 15 amino 

acids to its present day form of 64 codons for 20 amino acids. The structure of 

the present-day code permits a natural classification of the experimentally observed 

nucleotide substitutions between pairs of homologous nucleic acids descended from a 

common ancestral gene into subgroups reflecting constraints on function. The evolutionary information extractable from the experimental patterns among subgroups is 

shown for the genes of cytochrome C, alpha and beta hemoglobin, and for the genes 

that code for the VP1 and VP2 capsid proteins of the murine polyoma virus, simian 

SV40 virus, and human BK virus. To study Methanobacteriwn formicicum, we are in the 

initial phases of establishing a gene library of the entire genome of this organism 

in an Escherichia coli K-12 host using recombinant DNA techniques. From this library 

we will subclone a gene for an aminoacyl tRNA synthetase. In vitro studies are in 

progress which will establish whether any of the P4ethanobacteriwn formicicwn enzymes 

is capable of heterologous aminoacylation of tRNA from Escherichia coEi. The methanobacterial gene specifying the synthetase will be selected for in an E. coZi strain 

mutant for the synthetase. The gene library can also be probed for tRNA genes. Sequencing the chosen archaebacterial gene should help define archaebacterial transcriptional promotor and terminator sequences. This work should also contribute to 

the understanding of specificity of tRNA charging. The gene library can also be used 

to search for genetic functions involved in methanogenesis. The most readily approachable are genes carrying out the biosynthesis of two coenzymes--coenzyme M and the 

flavinoid pigment F420. 

94 
Determining the Origin and Early Evolution of Living Organisms 

Based on Protein and Nucleic Acid Sequence Data 

M.O. Dayhoff* 

Georgetown University Medical School 

Washington, D.C. 20007 

Many proteins and nucleic acids are "living fossils" in the sense that their 

structures have been dynamically conserved by evolution over billions of years: 

recognizably related molecules are found in eukaryotes and prokaryotes. Such 

molecules are believed to be of common evolutionary origin, having evolved by many 

small changes in the sequences. The positions in the aligned sequences can be used 

as traits in numerical taxonomy. From a comparison of the chemical structures in 

each sequence, an evolutionary scheme is deduced. These methods have proved quite 

successful: the 5s ribosomal RNA molecules elucidated from a wide variety of 

species give a comprehensive framework, as described below. It remains to add the 

hundreds of other phyla and major groups, to identify transfers of genetic 

material, and to make more precise computations using molecules with more 

information. Using the order of branching worked out from the sequences along with 

additional information on metabolic capacities and morphology, a very interesting 

evolutionary scheme will finally be worked out. 

The comprehensive tree that we derived from one molecule, 5s rRNA, unquestionably 

confirms the separate origins of the cytoplasmic constituents, the mitochondria 

and the chloroplasts of eukaryotes from three different prokaryote lineages, thus 

confirming the symbiotic theory of the origin of the organelles. The chloroplasts 

of higher plants derive from an ancestor of Anacystis and Prochloron; the 

mitochondria, from the purple nonsulfur bacteria; and the cytoplasmic 

constituents, from the archaebacterial line including Thermoplasma acidophilum and 

Sulfolobus acidocaldarius. There are a number of additional molecules from which 

substantial trees can be constructed, including 4Fe-4S ferredoxin, c-type 

cytochromes, and cytochrome c' from bacteria, 2Fe-2S ferredoxins of blue-greens 

and chloroplasts, and 5.8s ribosomal RNA sequences from eukaryotes. Essentially 

complete sequences of the principal ribosomal RNAs from the large and small 

subunits are known from a diverse group of prokaryotes, eukaryotes, and eukaryote 

organelles. An examination of the consistency of the trees supports the hypothesis 

that the transfer between species of genes for molecules of fundamental importance 

followed by persistence in evolution is a rare occurrence. 

The rate of sequence analysis has reached an explosive stage due to the recent 

breakthrough in nucleic acid sequencing techniques. There are now well over 

1,OOO,OOO nucleotides sequenced and this database is at least doubling every year. 

There is a great deal of information that has not been examined for phylogenetic 

inferences. The availability of the data is not the problem, as we are currently 

maintaining nucleic acid and protein sequence databases available on magnetic tape 

and through telephone access to a retrieval system on our computer. The problem 

now is to evaluate and provide standardized computer methods in a form practical 

for the systematist to use in phylogenetic analysis. It is possible to provide 

programs as well as the data through telephone access to computers elsewhere. We 

will discuss the feasibility of a collaboration of scientists interested in 

providing, evaluating, and maintaining computer programs for scientists who will 

be investigating the evolutionary process. 

95 
A LOW MOLECULAR WEIGHT, ARCHAEBACTERIAL ADENOSINE TRIPHOSPHATASE 

1,2 2 1* 

Hordur Kristjansson , Cyril Ponnamperuma , and Lawrence Hochstein 

1. EXTRATERRESTRIAL RESEARCH DIVISION 

AMES RESEARCH CENTER 

MOFFETT FIELD, CA 94035 

2.LABORATORY OF CHEMICAL EVOLUTION 

DEPARTMENT OF CHEMISTRY 

UNIVERSITY OF MARYLAND, COLLEGE PARK, MD 20742 

The membrane bound, energy transducing adenosine triphosphatases 

(ATPases) consist of two major structures. One, Fl, consists of 

5 subunits whose aggregate molecular weight is about 380,000 daltons. 

The other, F , is intimately associated with the membrane and consists of thrge subunits whose combined molecular weight is approximately 150,000 daltons. The ubiquitous distribution of these ATPases 

among prokaryotic and eukaryotic organisms, and their nearly similar 

structural and functional properties, suggest a highly conserved 

structure which arose early early during evolutionary history. Yet 

such a notion does not seem reasonable given the complexity of the 

ATPases and a process involving evolution from something simpler 

seems more attractive. 

We have been examining a number of halobacter for the presence of 

ATPase activity with the assumption that such organisms might possess 

a less highly evolved enzyme. We have detected ATPase activity in a 

number of extremely halophilic bacteria, and the enzyme from one of 

these, Halobacterium saccharovorum, has been partially purified and 

characterized. The enzyme exhibits many similarities to the proton 

translocating ATPase from other cells (i.e. K (ATP),K.(ADP), latency 

of activity, cold sensivity, and lack of subs?rate an& divalent 

cation specificity). However, 

an apparent molecular weight of 

the solubilized ATPase (i.e. Fl) has 

about 120,000 daltons as judged by 

gel filtration. Whether this low molecular weight represents a 5 

subunit structure where each subunit has a lower molecular weight 

than found in the subunits from other F structures, or the F from 

H. saccharovorum is an ATPase consist& of fewer subunits is'not 

&aar at this time. Either alternative would be consistent with a more 

primitive enzyme than that found in other organisms and suggests that 

the halobacteria may provide information on the origin and evolution 

of the energy transducing ATPases. 

96 
A YEAST-LIKE FIRST EUKARYOTE ? 

Helen S. Vishniac* and Siavash Baharaeen 

Oklahoma State University 

Stillwater Oklahoma 74078 

The most dramatic recent advances in our understanding of the origin of 

cellular life and of eukaryote life have been made as a result of comparing 

the nucleic acids of divers cells-and cell components. These origins remain 

controversial, though speculation has been directed into better defined 

channels by this research. At a less basic, but equally important, level 

the taxonomy of modern bacteria has been revolutionized by the work of Woese 

and his collaborators with catalogued oligonucleotides from 16s rRNA. The 

phylogenetic trees constructed from this and other comparisons indicate that 

a character must be derived (not indicating relationship) when it occurs on 

independent branches (necessarily tertiary branches), thus possessing the 

capability, when sufficient and appropriate organisms have been examined, of 

clarifying the nature of all but the first two branching of cellular life. 

Current phylogenetic trees compare relatively few organisms, because such 

research is time-consuming, and therefore have some important branches in 

regions of low, error-prone, homology. Hybridization techniques are the 

most rapid, and could be used to screen potential subjects for cataloguing 

and sequencing. We are developing a new method of 25s rRNA hybridization 

and exploring its use in the classification of basidiomycetous yeasts. One 

theorizer has proposed that yeasts were the first eukaryotes. We think this 

unlikely; molecular comparison is a sufficiently powerful tool to show 

whether unicellularity in the eufungi is a derived character. 

The unique yeasts of barren sites in the Dry Valleys of Antarctica have been 

shown by DNA-DNA homology to belong to several species probably originating 

outside of this habitat, though one species has evolved into several 

varieties within the Dry Valleys. The congeners of these sexless (anamorphic) 

yeasts were shown by cDNA-25s rRNA homology (by a new technique made possible 

by adding poly A tails ( ala Engel and Davidson, 1978, Biochem. 17: 3883) to 

400-600 mer fragments of isolated 25s rRNA, duplexing the tails with oligo 

d(T) and using reverse transcriptase (see Verma, 1981, The Enzymes 14: 87) 

to prepare tritiated cDNA) to be Filobasidiellas, a teleomorphic (sexy) genus 

which is not psychrophilic, but may have other preadaptations (to be examined) 

to Dry Valley life. In a three-dimensional map of cDNA-25s rRNA homology, 

the genera Filobasidiella, Filobasidium, Leucosporidium, and Rhodosporidium 

(the known teleomorphic basidiomycetous yeasts excepting Aessosporon and 

Sporidiobolus) are points enveloped in spheres of standard deviation, but 

separated by at least twice the standard error of difference. This technique 

defines genera and probably extends to the orders of traditional (but controversial) schemes, since Aessosporon (Uredinales) shows 44% homology to 

Rhodosporidium, but none to Filobasidium (Tilletiales). Regions of low DNA 

and RNA homology are not mappable, in part because of the large errors 

associated with low homology, to which all molecular comparisons are subject, 

but also because different parts of the probed molecules are duplexing with 

the probe. The 5S r-RNA trees of Hori and Osawa (1979, PNAS 76: 381), compared 

with the work of Bicknell and Douglas (1970, J. Bact. 101: 505) on 25s rRNA 

homology (by the method of Gillespie, 1968, Meth. Enzymol. 12B: 641) in 

Saccharomyces sensu lato suggests that low homologies becomayhigher when 

shorter rRNA molecules are used. Our technique would be a useful screen in 

establishing the bona fides of subjects for sequencing of smaller rRNAs. 

Sequence comparison, though still requiring interpretation, allows linear 

comparison of whole molecules. 

97 
OXYGEN REQUIREMENTS FOR LIPID SYNTHESIS IN MICROORGANISMS 

Linda Jahnke*, Carol Volkmann and Harold P. Klein 

Ames Research Center 

Moffett Field, California 94035 

Life on Earth presumably originated in an essentially anaerobic environment. At some time, perhaps as much as 3.3 billion years ago, the process of 

oxygenic photosynthesis was "invented" and oxygen gradually accumulated in the 

atmosphere. What the history of atmospheric oxygen was before this period is 

obscure. However, from the standpoint of evolutionary development, the biological production of oxygen was crucial. Classical evolutionary thought would 

suggest that anoxygenic metabolic pathways are more "primitive" than oxygenrequiring ones. Indeed, the presence of oxygen-requiring metabolic processes 

in eucaryotes has been used as an argument that these organisms appeared after 

the atmosphere became oxygenic. We have been studying unsaturated fatty acids 

and sterols, compounds known to require atmospheric oxygen for their formation 

in eucaryotes. However, in both cases there exist alternative anoxygenic 

pathways resulting in functionally equivalent compounds, i.e., monounsaturated 

fatty acids and hopanes. Additionally there appears to be some phylogenetic 

relationship; procaryotes predominantly utilize the anoxygenic mechanisms, and 

eucaryotes the oxygenic ones. Even in the eucaryotes, however, little attention 

has been paid to the levels of oxygen necessary to carry out the syntheses of 

unsaturated fatty acids and sterols. In the simple eucaryote, S. cerevisiae, 

we have demonstrated that the oxidative desaturation of palmitic acid and the 

conversion of squalene to sterols occur in the range of 0.002 PAL to 0.01 PAL. 

Thus biological systems interacting with oxygen in eucaryotes could have been 

operational relatively early in biological evolution, and these "aerobic" 

processes more primitive than previously thought. 

Recent work has continued on the oxygen-requiring processes of lipid 

synthesis in microorganisms. The conversion of squalene to ergosterol, a 

metabolic process involving at least five individual oxygen-requiring enzymes, 

has been investigated in yeast. We have developed an in vitro system for 

the conversion of squalene to lanosterol in which squa%%xpreferentially 

converted to lanosterol by particulate preparations of anaerobic cells. In 

this system, addition of the inhibitor AMO-1618 results in accumulation of 

2,3-oxidosqualene and allows the squalene epoxidase, the first oxygen-requiring 

step, to be investigated. The "apparent7 half-maximal activity for the 

epoxidase is reached at an oxygen concentration equivalent to 0.01 PAL. 

In vivo studies on the oxygenation of anaerobic cells have shown that the -- 

epoxidase activity doubles at a level of only 0.001 PAL. In other studies, 

we have found that this low level of oxygen completely stabilized the 

palmitoyl-CoA desaturase system in these organisms. Additionally, we have 

recently initiated studies on the formation of mono- and polyunsaturated 

fatty acids in cyanobacteria. Using a culture of Nostoc sp. in which their --- --- 

oxygen-generating photosystem II is poisoned by DCMU, coupled with the presence - 

of Na,S, 

oxyge6, 

we have found that these desaturations, which require atmospheric 

occur at levels of oxygen below 0.012 PAL. 

98 
PRIMARY AND SECONDARY ENERGY CONVERSION IN HALOBACTERIUM 

MEMBRANES 

Janos K. Lanyi* and Brigitte Schobert 

Dept. of Physiology and Biophysics 

University of California, Irvine, CA 92717 

A distinct milestone in the origin of life is the 

establishment of biological individuality, i.e. the delimitation of space to include a specific group of molecules and exclude others. It is only a small step from 

here to acquire the ability to maintain a chemical environment within this space which is different from the 

surroundings, and which is kept constant in the face of 

outside influences. It is reasonable to believe that it 

was a proto-membrane,and vectorial catalysts in it,that 

made this step possible. In this context studies of simple 

energy conversion systems in present-day biological membranes are needed to develop models for the membrane energetics of a primitive cell. It is f.ortunate that such 

systems, based on light energy utilization, exist in the 

halobacteria, which are thought to be, as members of the 

archebacterial group, organisms with preserved ancient 

properties. We have identified mechanisms for sodium and 

chloride transport in halobacterial membranes. 

Sodium ions are removed from halobacterial cells via 

a coupled primary/secondary transport system consisting of 

a proton loop (bacteriorhodopsin) and a sodium loop (sodium/ 

proton antiporter). The activity of these loops results in 

the recirculation of extruded protons and the continued extrusion of sodium. The antiporter appears to be electrogenic 

in that 2 protons are exchanged for one sodium. It is a 

gated system, which results in rectification of the sodium 

flux in the physiologically meaningful (outward) direction. 

The electrical potential which develops has two important 

consequences. One is that potassium is transported inside, 

probably by a passive mechanism, so that sodium is replaced 

by potassium. The other is that chloride is passively lost, 

resulting in net loss of salt and therefore water and volume. 

This chloride is regained by a second active transport system 

(halorhodopsin), which we find functions as a direct, inward 

directed chloride pump. The combined action of these transport systems results in the maintenance of sodium/potassium 

gradients across the membrane and constant volume. 

99 
LIGHT ENERGY CONVERSIOr\l IN HALOBACTERIA 

Roberto P. Fogomolni* and Walther Stoeckenius 

University of California 

San Francisco, California 34143 

!fi!e are investigatinq the structure and function of a new 

biological energy 'transducing system embedded in the cell 

membrane of Halobacteria which live in natural brine pools. 

Halobacteria are now clasified as Archaebacteria implying 

that they are among the oldest living cells. Therefore these 

organisms are of special interest for the evolution of life 

and survival in extreme enviroments. Racteriorhodopsin 

functions as a light driven proton pump which ejects protons 

from the cell. The resulting electrochemical potential 

across the cell membrane is chemiosmotically coupled to 

energy requiring processes such as ATP synthesis, ion and 

aminoacid transport, and locomotion. The purpose of our 

research is to understand the structure and function of this 

pigment, which is the simplest and presumably earliest ion 

pump and light energy-transducing pigment known. 

We are using conventional and time-resolved absorption spectroscopy in the visible and U.V. range, routine biochemical 

techniques and recently pulse radiolysis to characterize the 

pigment. We have determined Lys-216 as the retinal 

chromophore-binding site and shown that the earlier 

described site at Lys-41, observed only under special conditions, is presumably an artifact but can be used to obtain 

information on the 3-dimensional structure of the protein. 

Ultraviolet absorbance changes during the bacteriorhodopsin 

photocycle indicate that tyrosine group(s) undergo transient 

deprotonation. !\re have selectively nitrated one tyrosine 

residue that affects spectroscopic and photocycle kinetics. 

The data suggests that this residue is involved in a proton 

transfer reaction. We are trying to locate this group in the 

sequence and, if possible in the 3-dimensional 

structure,either by refinement of existing structural data 

or after labeling with heavy atoms. 

We have recently isolated from natural brines several new 

strains, which carry similar or identical pigments, which 

will he compared, using our standard techniques, to bacteriorhodopsin and to the recently discovered halorhodopsin 

to see if variations in the structure occur and tiich components are essential for function. 

100 
THE CRYPTOENDOLITHIC MICROBIAL COMMUNITY: A "CLOSED" ECOSYSTEM 

IN NATURE 

E. Imre Friedmann+ *, Roseli 0. Friedmann+, Ludger Kappen++, 

Christopher C. McKay+++, and J. R&ie Vestal++++ 

+Florida State University 

Tallahassee, Florida 32306 

++University of Kiel 

Federal Republic of Germany 

+++NASA Ames Research Center 

Moffett Field, California 

++++University of Cincinnati 

Cincinnati, Ohio 45221 

Cryptoendolithic microorganisms living in rocks of the Antarctic 

cold desert are highly specialized because they are adapted to 

an extreme environment. Yet the structure of this ecosystem is 

simple. It consists only of primary producers, consumers and 

decomposers; secondary consumers and predators are absent and 

the number of species is very small. Such a system may be regarded as a model for primitive, archaic conditions. The physical 

and chemical components can be expressed in comparatively few 

parameters and this makes it suitable for quantitative study. 

This ecosystem can exist in balanced condition due to the fact 

that it is closed to a considerable degree. Ecosystem closure 

can range from adiabatic isolation (closed to the flow of matter 

and energy) to biological closure (Maguire et al., Microcosms in 

ecological research, U. S. Dept. Energy, Symp. Ser., 52, 1980). 

The cryptoendolithic ecosystem is biologically closed on the 

biological timescale (but is open on the geological timescale). 

At the same time, flow of matter is significantly restricted. 

Preliminary results indicate that an inner CO2 pool exists in the 

endolithic airspace which controls photosynthesis. Keeping biomass below a certain limit (by regulating primary productivity) 

is a necessity in the physically limited space of the cryptoendolithic microenvironment. 

101 
.-..... . . .,, . . . . . . . . . . . . . . . . ..-... . --- -..-- __-.----- 

B 5 

/ 

AUTHOR INDEX 

102 
Abell, P.I. 

Allen, M. 

Alvarez, L.W. 

Alvarez, W. 

Asaro, F. 

Baharaeen, S. 

Barengoltz, J.B. 

Barghoorn, E.S. 

Bar-Nun, A. 

Benson, R. 

Billingham, J. 

Bogomolni, R.A. 

Bonner, W.A. 

Bossard, A. 

Burlingame, A.L. 

Burt, S.K. 

Bush, J. 

Bzik, S. 

Campbell, S.E. 

Carle, G.C. 

Chang, S. 

Cherayil, B. 

Church, F. 

Coyne, L.M. 

AUTHOR INDEX 

Page 

83 

45 

90 

90 

90 

97 

74 

82 

49 

44 

78 

100 

57 

44 

89 

67 

94 

53 

88 

70,72 

39,43,49 

60 

53 

55 

Cronin, J.R. 

Dayhoff, M.O. 

DeFrees, D. 

Des Marais, D. 

DeVincenzi, D.L. 

Drake, F.D. 

Eirich, F.R. 

Fakhrai, H. 

Ferris, J.P. 

Folsome, C.E. 

Fox, G.E. 

Fox, S.W. 

Friedmann, E. I. 

Friedmann, R.O. 

Frye, J.S. 

Golubic, S. 

Hartman, H. 

Gardner, E.P. 

Gupta, S. 

Hayes, J.M. 

Hobish, M. 

Hochstein, L. 

Holmquist, R. 

Inoue, T. 

Page 

40 

95 

38 

84 

74 

80 

64 

62 

44 

51 

93 

63 

101 

101 

40 

88 

52 

45 

39 

85 

60,77 

96 

94 

62 

103 
Jahnke, L. 

Jukes, T. 

Kaplan, I.R. 

Kappen, L. 

Kasting, J.F. 

Kieber-Emmons, T. 

Khare, B.N. 

Klein, H.P. 

Kojiro, D.R. 

Kristjansson, H. 

Kuhn, W.R. 

Lacey, J.C., Jr. 

Lanyi, J.K. 

Lawless, J. 

Levy, N. 

Loew, G. 

MacElroy, R.D. 

Margulis, L. 

Martin, A. 

Mazzurco, J. 

McClory, J. 

McKay, C.C. 

McLean, D. 

Michel, H.V. 

Miller, S.L. 

Page 

98 

94 

86 

101 

48 

66 

46 

98 

69,70 

96 

42 

65 

99 

39,53 

53 

38 

67 

92 

83 

53 

83 

101 

38 

90 

50 

Mortland, M. 

Nagy, B. 

Nakashima, T. 

Nisbet, E. 

Ogino, H. 

O'Hara, B.J. 

Orenberg, J.B. 

Orgel, L.E. 

Oro, J. 

Paecht-Horowitz, M. 

Phillips, J.B. 

Pinto, J.P. 

Pizzarello, S. 

Pohorille, A. 

Pollock, G.E. 

Ponnamperuma, C. 

Postawko, S.E. 

Raup, D. 

Rein, R. 

Sagan, C. 

Scattergood, T.W. 

Schlesinger, G. 

Schobert, B. 

Shipp, R. 

Smith, G.G. 

Page 

53 

41 

63 

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58 

62 

61,79 

64 

72 

45 

40 

67 

69 

60,77,96 

42 

78 

66 

46 

43 

50 

99 

39 

87 

104 
Stabekis, P.D. 

Stoeckenius, W. 

Stolz, J.F. 

Strother, P.K. 

Syren, R.M. 

Valentin, J.R. 

Vestal, J.R. 

Vishniac, H.S. 

Volkmann, C. 

Walker, J.C.G. 

Page 

74 

100 

92 

82 

63 

72 

101 

97 

98 

48 

135 

- - 

Weber, A.L. 

Wedeking, K.W. 

White, D.H. 

Woeller, F.H. 

Woese, C.R. 

Wood, J.A. 

Wydeven, T. 

Yuen, G.U. 

Yung, Y.L. 

Zahnle, K.J. 

Page 

56 

85 

54 

69,70 

93 

76 

39 

40 

45 

48 
APPENDIX 

106 
APPENDIX 

PARTICIPANTS 

Abell, Paul I. 

Chemistry Dept. 

University of Rhode Island 

Kingston, RI 02881 

Altekar, Wijaya 

Mail Stop 239-10 

Ames Research Center 

Moffett Field, CA 94035 

Alvarnas, Joseph 

(U. Santa Clara) 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Antoun, Karen 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Arrhenius, Gustav 

Scripps Institute of 

Oceanography 

University of San Diego 

San Diego, CA 92101 

Asaro, Frank 

Lawrence Berkeley Laboratory 

1 Cyclotron Road 

MS-70-11OA 

Berkeley, CA 94720 

Askoff, Keith G. 

Cornell University 

Ithaca, NY 14853 

Backus, Peter 

(Dudley Observatory) 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

Baker, Thomas 

35 Paumanake Avenue 

Babylon, NY 11702 

Bald, Laura 

(San Jose State U. ) 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Benson, Robert 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Bergstrom, Sheryl L. 

Mail Code 122-123 

Jet Propulsion Lab 

4800 Oak Grove Dr. 

Pasadena,‘CA 91109 

Billingham, John 

Mail Stop 239-11 

Ames Research Center 

Moffett Field, CA 94035 

Bogomolni, Roberto 

School of Medicine 

University of California 

San Francisco, CA 94143 

Bonner, William A. 

Chemistry Dept. 

Stanford University 

Stanford, CA 94305 

Boston, Penelope J. 

University of Colorado 

Boulder, CO 80309 

107 

- 
Bowles, Sherri 

(San Jose St.ate U.) 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Brimblecombe, Peter 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Buescher, Vera 

(San Francisco State U.) 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

Burlingame, A.L. 

Dept. of Pharmaceutical 

Chemistry 

University of California 

San Francisco, CA 94143 

Burt, Stan 

Mail Stop 239-10 

Ames Research Center 

Moffett Field, CA 94035 

Bush, John 

Space Sciences Lab 

University of California 

Berkeley, CA 94720 

Byerly, Gary 

Louisiana State University 

Dept. of Geology 

Baton Rouge, LA 70803 

Bzik, Sara 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Calderon, John 

(U. Santa Clara) 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Carle, Glenn C. 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Carroll, Arthur 

(College of Santa Fe) 

ASEE-NASA Program 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Chang, Sherwood 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Chung, Ling Fong 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Church, Frank 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Cole, Raymond 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

Colombano, Silvano 

Mail Stop 239-4 

Ames Research Center 

Moffett Field, CA 94035 

Cortes, Alejandro 

University of Mexico 

Faculty of Medicine 

Mexico City, Mexico 

Coyne, Lelia M. 

(San Jose State U.) 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

108 
Craig, Roger 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Cronin, John R. 

Dept. of Chemistry 

Arizona State University 

Tempe, AZ 85282 

Cronin, Sonja 

Mail Stop 239-10 

Ames Research Center 

Moffett Field, CA 94035 

Cullers, Carol 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

Cullers, Kent 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

Day, John 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

Dayhoff, Margaret 0. 

National Biomedical Research 

Foundation 

Georgetown University 

Medical Center 

3900 Reservoir Road, N.W. 

Washington, DC 20007 

De Frees, Doug 

Molecular Research Institute 

701 Welch Road, Suite 203 

Palo Alto, CA 94304 

Des Marais, David J. 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

DeVincenzi, Donald L. 

Code EBT-3 

NASA Headquarters 

Washington, DC 20546 

Drake, Frank D. 

NAIC 

Cornell University 

Ithaca, NY 14853 

Dudzinski, Diane 

(College of Santa Fe) 

Mail Stop 239-4 

Ames Research Center 

Moffett Field, CA 94035 

Eirich, Frederick R. 

Dept. of Chemistry. 

Polytechnic Institute of 

New York 

333 Jay St. 

Brooklyn, NY 11201 

Erlichman, Josef 

Mail Stop 245-5 

Ames Research Center 

Moffett Field, CA 94035 

Fahey, Robert C. 

Chemistry D-006 

University of California, 

San Diego 

La Jolla, CA 92093 

Ferris, James P. 

Chemistry Dept. 

Cogswell Laboratory 

Rensselaer Polytechnic 

Institute 

Troy, NY 12181 

Fl ores, Jose 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Folsome, Clair E. 

Exobiology Laboratory 

Dept. of Microbiology 

University of Hawaii, Manoa 

Honolulu, HI 96822 

Fox, George E. 

Dept. of Biochemical 

and Biophysical Sciences 

University of Houston 

Houston, TX 77004 

109 
-.--._ .._-_____ __. 

Friedmann, E. Imre 

Dept. of Biological Sciences 

Florida State University 

Tallahassee, FL 32306 

Garavelli, John S. 

(Texas A & M) 

Mail Stop 239-4 

Ames Research Center 

Moffett Field, CA 94035 

Gibson, Everett K. 

NASA-Johnson Space Center 

SU7, Geochemistry, NASA-JSL 

Houston, TX 77058 

Golubic, Stjepko 

Dept. of Biology 

Boston University 

Boston, MA 02215 

Grant, Michael A. 

Mail Stop 239-10 

Ames Research Center 

Moffett Field, CA 94035 

Gupta, Abha 

Molecular Research Institute 

701 Welch Road, Suite 203 

Palo Alto, CA 94304 

Gupta, Subhash 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Hartman, Hyman 

Dept. of Earth and Planetary 

Sciences 

Massachusetts Institute of 

Technology 

Cambridge, MA 02139 

Hastings, Nancy 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Hobish, Mitchell 

Laboratory of Chemical 

Evolution 

Dept. of Chemistry 

University of Maryland 

College Park, MD 20742 

Hochstein, Lawrence I. 

Mail Stop 239-10 

Ames Research Center 

Moffett Field, CA 94035 

Holmquist, Richard 

Space Sciences Laboratory 

University of California, 

Berkeley 

1414 Harbour Way South 

Richmond, CA 94804 

Hsu, Alice 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

Jahnke, Linda 

Mail Stop 239-10 

Ames Research Center 

Moffett Field, CA 94035 

Juriansz, Eleanor 

Laboratory of Chemical 

Evolution 

Dept. of Chemistry 

University of Maryland 

College Park, MD 20742 

Kaplan, Isaac R. 

Institute of Geophysics and 

Planetary Physics 

University of California 

Los Angeles, CA 90024 

Kojiro, Dan 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

110 
Krekorian, Robert 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

Kristjansson, Hordur 

(U. of Maryland) 

Mail Stop 239-10 

Ames Research Center 

Moffett Field, CA 94035 

Kvenvolden, Keith 

U.S. Geological Survey 

345 Middlefield Road 

Menlo Park, CA 94025 

Kwong, Emil 

(San Jose State University) 

1771 Cleveland Avenue 

San Jose, CA 95126 

Lacey, Jr. James C. 

Dept. of Biochemistry 

University of Alabama 

University Station 

P.O. Box 319 

Birmingham, AL 35294 

Lahav, Noam 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Lanyi, Janos K. 

Dept. of Physiology and 

Biophysics 

University of California 

Irvine, CA 92717 

Lawless, James G. 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Lehwalt, Marjorie 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Linscott, Ivan R. 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

Loew, Gilda H. 

Molecular Research Institute 

701 Welch Road, Suite 203 

Palo Alto, CA 94304 

Lord, Steve 

(NASA-ASEE) 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

MacElroy, Robert D. 

Mail Stop 239-4 

Ames Research Center 

Moffett Field, CA 94035 

Margulis, Lynn 

Dept. of Biology 

Boston University 

Boston, MA 02215 

Mazzurco, Jerri 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

McKay, Christopher P. 

Mail Stop 245-3 

Ames Research Center 

Moffett Field, CA 94035 

Mead, Susan 

Mail Stop 239-11 

Ames Research Center 

Moffett Field, CA 94035 

Melius, Paul 

Dept. of Chemistry 

Auburn University 

Auburn, AL 36830 

111 
Miller, Stanley L. 

Dept. of Chemistry, B-017 

University of California, 

San Diego 

La Jolla, CA 92093 

Milne, David 

(Evergreen College) 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

Minners, Sjhon 

(U. New Hampshire) 

Mail Stop 239-14 

Ames Research Center 

Moffett Field, CA 94035 

Mittman, Michael 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Mortland, Maxwell 

(NRC) 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Munoz, Elaine 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Nagy, Bartholomew 

Laboratory of Organic 

Geochemistry 

533 Space Science Building 

University of Arizona 

Tucson, AZ 85721 

Nagy, Lois 

Laboratory of Organic 

Geochemistry 

533 Space Science Building 

University of Arizona 

Tucson, AZ 85721 

Nibley, Carle 

(U. Santa Clara) 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Obinhiba, Donald C. 

Univ. of Hawaii 

Dept. of Microbiology 

Honolulu, HI 96826 

Ocampo-Friedmann, Roseli 

Dept. of Biological Science 

Florida State University 

Tallahassee, FL 32306 

Ogino, Hiroshi 

Laboratory of Organic 

Geochemistry 

533 Space Science Building 

University of Arizona 

Tucson, AZ 85721 

O'Hara, Bonnie 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

O'Hara, Dean 

(EAL) 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Oie, Tetsuro 

Molecular Research Institute 

701 Welch Road, Suite 203 

Palo Alto, CA 94304 

Olsen, Jerry 

(Stanford U.) 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

112 
Orenberg, James B. 

Chemistry Dept. 

San Francisco State University 

1600 Halloway Avenue 

San Francisco, CA 94132 

Orgel, Leslie E. 

The Salk Institute for 

Biological Studies 

P.O. Box 85800 

San Diego, CA 92138 

Oro, John 

Dept. of Biochemical Sciences 

Laboratory of Biomolecular 

Analysis 

University of Houston 

Houston, TX 77004 

Persky, James H. 

Boston University 

Dept. of Geology 

725 Commonwealth Avenue 

Boston, MA 02215 

Peterson, Etta 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Pohorille, Andrew 

(U. California Berkeley) 

Mail Stop 239-10 

Ames Research Center 

Moffett Field, CA 94035 

Pollock, Glenn E. 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Rambler, Mitchell 

Code EBT-3 

NASA Headquarters 

Washington, DC 20546 

Raup, David 

Field Museum 

Roosevelt Road at Lake 

Shore Drive 

Chicago, IL 60605 

Rau, Greg 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Rein, Robert 

Experimental Pathology 

Roswell Park Memorial Institute 

666 Elm Street 

Buffalo, NY 14263 

Rishpon, Judith 

Chemistry Dept. 

Tel Aviv University 

Tel Aviv, Israel 

Roy, Deanna 

Mail Stop 239-10 

Ames Research Center 

Moffett Field, CA 94035 

Rubin, Robert 

Mail Stop 245-6 

Ames Research Center 

Moffett Field, CA 94035 

Satya T. 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Sagan, Carl E. 

302 Space Sciences Bldg. 

Cornell University 

Ithaca, NY 14853 

Scattergood, Thomas W. 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Seaborg, David 

University of California 

Berkeley, CA 94720 

Seeger, Cassandra 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

113 
Seeger, Charles 

(U. San Francisco State) 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

Seeger, Naomi 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

Sharp, Joseph 

Mail Stop 200-7 

Ames Research Center 

Moffett Field, CA 94035 

Shipp, Ruth 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Shock, Everett 

University of California 

Dept. of Geology and 

Geophysics 

Berkeley, CA 94720 

Smestad, Greg 

(U. Santa Clara) 

Mail Stop 239-11 

Ames Research Center 

Moffett Field, CA 94035 

Smith Adolph 

Mail Stop 239-11 

Ames Research Center 

Moffett Field, CA 94035 

Smith, Grant Gill 

UMC 03 Dept. of Chemistry 

Utah State University 

Logan, UT 84322 

Stabekis, Perry D. 

Exotech Research and 

Analysis Inc. 

1200 Quince Orchard Blvd. 

Gaithersburg, MD 20760 

Stolz, John 

Boston University 

Dept. of Biology 

Boston, MA 02215 

Sugikawa, Jean Y. 

(U. Santa Clara) 

Mail Stop 239-11 

Ames Research Center 

Moffett Field, CA 94035 

Swan, Kathryn 

(NASA-Ames Res. Ctr.) 

225 Church Street 

Mt. View, CA 94041 

Tarter, Jill 

Mail Stop 229-8 

Ames Research Center 

Moffett Field, CA 94035 

Valentin, Jose R. 

(Southern Illinois U.) 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Vishniac, Helen S. 

Dept. of Botany and Microbiology 

Oklahoma State University 

Stillwater, OK 74078 

Walsh, Maud 

Geology Dept. 

Louisiana State University 

Baton Rouge, LA 70803 

Walton, Barbara 

(Informatics) 

Mail Stop 239-11 

Ames Research Center 

Moffett Field, CA 94035 

Weaver, David 

Mail Stop 239-4 

Ames Research Center 

Moffett Field, CA 94035 

114 
Weaver, Ellen 

(San Jose State University) 

Mail Stop 239-10 

Ames Research Center 

Moffett Field, CA 94035 

Weber, Arthur L. 

The Salk Institute for 

Biological Studies 

P.O. Box 85800 

San Diego, CA 92138-9216 

Weber, Esther Varon 

The Salk Institute for 

Biological Studies 

P.O. Box 85800 

San Diego, CA 92138-9216 

Wedeking, Kim W. 

Biogeochemical Laboratories 

Chemistry Bldg. 

Indiana University 

Bloomington, IN 47405 

Wharton, Jr., Robert A. 

Mail Stop 239-4 

Ames Research Center 

Moffett Field, CA 94035 

White, David H. 

Chemistry Dept. 

University of Santa Clara 

Santa Clara, CA 95053 

Wilson, Cathy 

301 Earth Science Bldg. 

University of California 

Berkeley, CA 94720 

Woeller, Fritz H. 

Mail Stop 239-12 

Ames Research Center 

Moffett Field, CA 94035 

Wood, John A. 

Harvard-Smithsonian Center 

for Astrophysics 

Cambridge, MA 02138 

Wrigley, Robert C. 

Mail Stop 242-4 

Ames Research Center 

Moffett Field, CA 94035 

Yopp, John 

Dept. of Biology 

Southern Illinois University 

Carbondale, IL 62901 

Yung, Yuk L. 

Div. of Geology and Planetary 

Science 

California Institute of 

Technology 

Pasadena, CA 91125 

Zahnle, Kevin 

Dept. of Atmosphere Sciences 

David Dennison Bldg. 

University of Michigan 

Ann Arbor, MI 48109 

115 
1. Report No. 

NASA ~~-2276 

2. Government Accession No. 

.~ -- 

3. Recipient’s Catalog No. 

L ~... I -- 

4. Title and Subtitle 5. Report Date 

First Symposium on Chemical Evolution and the May 1983 

Origin and Evolution of Life 6. Performing Organization Code 

7. Author(s) 8. Performing Organization Report No. 

Donald L. DeVincenzi and Linda G. Pleasant (eds.) 

10. Work Unit No. 

9. Performing Organization Name and Address 

National Aeronautics and Space Administration 11. Contract or Grant No. 

Life Sciences Division 

Washington, D.C. 20546 

13. Type of Report and Period Covered 

2. Sponsoring Agency Name and Address Conference Publication 

National Aeronautics and Space Administration 14. Sponsoring Agency Code 

Washington, D.C. 20546 EBT-3 

5. Supplementary Notes 

6. Abstract 

This three day conference was held at the NASA Ames Research Center 

on August 2-4, 1982. This symposium provided an opportunity for 

all NASA Exobiology principal Investigators to present their 

most recent research in a scientific meeting forum. Papers were 

presented in the following exobiology areas: extraterrestrial chemistr 

primitive earth, information transfer, solar system exploration, 

planetary protection, geological record, and early biological evolution. 

‘. Key Words (Suggested by Author(s)) 18. Distribution Statement 

Exobiology: Planetary protection Uncldssified - unlimited 

Extraterrestrial chemistry STAR Category 23 

Primitive earth; biological evol.; 

Solar system exploration 

I. Security Classif. (of this report) 

Unclassified 

20. Security Classif. (of this page) 

Unclassfied 

21. No. of Pages 22. Price 

120 A06 

For sale by the Natronal Technical Information Service, Springfield. Vrrgrnra 22161 

NASA-Lanpley, 1983