bluuebunny/crossref_metadata_2025 huggingface dataset:
A Multiple Origin for Plastids and Mitochondria
Authors: Raven Peter H.
Published: October 2006

The impressive homologies between mitochondria and plastids, on the one hand, and procaryotic organisms, on the other, make it almost certain that these important cellular organelles had their origin as independent organisms. The vast number of symbiotic relationships of all degrees of evolutionary antiquity which have been found in contemporary organisms point to the ease with which such relationships can be established.

In view of this, the similarities between such totally different groups as blue-green algae and red algae, dinoflagellates and brown algae, and green algae and euglenoids can best be explained by postulating an independent, symbiotic origin of the plastids in each instance. A minimum of three groups of photosynthetic procaryotes appears to be necessary to explain the relationships among contemporary Protista and green plants: (i) the blue-green algae, which possess chlorophyll
a
, carotenoids, and phycobilins; (ii) the "green procaryotes," a hypothetical group characterized by chlorophylls
a
and
b
and a distinctive assemblage of carotenoid accessory pigments, but not phycobilins; and (iii) the "yellow procaryotes," a second hypothetical group whose members had chlorophylls
a
and
c
and various carotenoids but not phycobilins. There is, however, no reason to think that only three kinds of organisms were involved; numerous symbiotic events presumably occurred in each of these lines.

The "green procaryotes" and "yellow procaryotes" survive today only as chloroplasts from which the characteristics of the original, free-living forms can be deduced only in part. Hybridization between selected plastid DNA's may be helpful in unraveling this story, and is likewise suggested as the key to understanding the relationship between the blue-green algae and the chloroplasts of the red algae and cryptomonads.

It is postulated that the symbiotic organisms have lost various functions to the nucleus in the course of evolutionary time. If mitochondria and plastids have had a multiple origin, as suggested here, it will be necessary to examine the division of function between the two subsets of DNA for a wide variety of organisms before valid conclusions can be obtained.
Peptide Immunogen Mimicry of a Protein-Specific Structural Epitope on Human Choriogonadotropin
Authors: Bidart Jean-Michel , Troalen Frederic , Ghillani Pascale , Rouas Nathalie , Razafindratsita Alain , Bohuon Claude , Bellet Dominique
Published: October 2006

It is a challenge to construct synthetic immunogens that elicit antibodies (Abs) both directed to conformational epitopes and specific for a complex protein like human choriogonadotropin (hCG). A monoclonal antibody specific for hCG bound to regions around Lys
45
of the α subunit (hCGα) and Asp
112
of the β subunit (hCGβ). A peptide comprising residues 46 to 55 of hCGα and residues 106 to 116 of hCGβ elicited Abs in rabbits that were directed to a discontinuous epitope and were specific for hCG. These Abs inhibited the binding of hCG to its receptor. Thus, a synthetic immunogen can mimic a conformational-specific epitope and can be useful for vaccine development.
Acetylcholine Concentrations in Rat Brain: Diurnal Oscillation
Authors: Hanin I. , Massarelli R. , Costa E.
Published: October 2006

A diurnal oscillation of acetylcholine concentrations in rat brain has been demonstrated by gas chromatography. Peak concentrations occur at 2 hours of light, and a trough is seen at 6 hours of darkness. This pattern is observed only in grouped rats, and emerges after at least 18 days of prior conditioning in an environment with controlled light, humidity, and temperature.
Neuromuscular Synapse: Stochastic Properties of Spontaneous Release of Transmitter
Authors: Rotshenker S. , Rahamimoff R.
Published: October 2006

The spontaneous quantal release of transmitter from the motor nerve endings is a random process which follows the Poisson theorem; the liberation of each quantum is independent of the release of previous quanta. Increase in the extracellular calcium concentration produces a statistical interdependence in the release of the spontaneously appearing packages.
Slow Synaptic Excitation in Sympathetic Ganglion Cells: Evidence for Synaptic Inactivation of Potassium Conductance
Authors: Weight Forrest F. , Votava Jiri
Published: October 2006

The slow excitatory postsynaptic potential (EPSP) was investigated in frog sympathetic ganglion cells. In contrast to the increased conductance associated with other known EPSP's, during the slow EPSP resting membrane conductance was decreased. Electrical depolarization of the membrane potentiated the slow EPSP, whereas progressive hyperpolarization decreased its size and then reversed it to a hyperpolarizing potential (the opposite of the effect of membrane polarization on other EPSP's). The reversal potential of the slow EPSP was close to the potassium equilibrium potential. We propose that the slow EPSP, in contrast to classical EPSP's, is generated by an inactivation of resting potassium conductance.
Inversion of Excited States of Transition-Metal Complexes
Authors: Crosby G. A. , Watts R. J. , Carstens D. H. W.
Published: October 2006

The nature of the emission from central metal ions in complexes can be controlled by chemical alteration of the ligands. For iridium(III) species three types of emission have been observed, each originating from a different and orbitally identifiable excited state. Principles useful for designing new luminescent materials are formulated. They can be used for guiding photochemical research and for designing new analytical methods.
Man-Made Climatic Changes
Authors: Landsberg Helmut E.
Published: October 2006

Natural climatic fluctuations, even those of recent years, cover a considerable range. They can be characterized as a "noise" spectrum which masks possible global effects of man-caused increases of atmospheric CO
2
and particulates. Local modifications, either deliberate or inadvertent, measurably affect the microclimate. Some artificial alterations of the microclimate are beneficial in agriculture. Among the unplanned effects, those produced by urbanization on local temperature and on wind field are quite pronounced. The influences on rainfall are still somewhat controversial, but effects may extend considerably beyond the confines of metropolitan areas. They are the result of water vapor released by human activity and of the influence of condensation and freezing nuclei produced in overabundance by motor vehicles and other combustion processes. Therefore it appears that on the local scale man-made influences on climate are substantial but that on the global scale natural forces still prevail. Obviously this should not lead to complacency. The potential for anthropogenic changes of climate on a larger and even a global scale is real. At this stage activation of an adequate worldwide monitoring system to permit early assessment of these changes is urgent. This statement applies particularly to the surveillance of atmospheric composition and radiation balance at sites remote from concentrations of population, which is now entirely inadequate. In my opinion, man-made aerosols, because of their optical properties and possible influences on cloud and precipitation processes, constitute a more acute problem than CO
2
. Many of their effects are promptly reversible; hence, one should strive for elimination at the source. Over longer intervals, energy added to the atmosphere by heat rejection and CO
2
absorption remain matters of concern.
Coral Skeletons: An Explanation of Their Growth and Structure
Authors: Barnes David J.
Published: October 2006

Coral skeletons are constructed of aragonitic crystals organized into fan systems. A theoretical model for the growth of such fan systems, which depends upon competition between crystals for space in which to grow, is corroborated by vital staining with sodium alizarinesulfonate. Fan systems of crystals compete with each other to form larger fan systems until large, relatively stable fans are produced. It is these relatively stable fan systems that have been observed in optical thin sections of coral skeletons.
Improvement of Learning in the Aged by Modification of Autonomic Nervous System Activity
Authors: Eisdorfer Carl , Nowlin John , Wilkie Frances
Published: October 2006

Partial blockade of beta-adrenergic end-organ response to the autonomic nervous system was effected in a group of older men by administration of propranolol. The result was improved performance in a learning task. The data support the hypothesis that the learning decrement found among older men is not simply a manifestation of structural change in the central nervous system but is, at least in part, associated with the heightened arousal of the autonomic nervous system that accompanies the learning task.
Visual Adaptation in Monkey Cones: Recordings of Late Receptor Potentials
Authors: Boynton Robert M. , Whitten David N.
Published: October 2006

The retinal cones of cynomolgus macaque monkeys show marked amounts of adaptation when the receptor potential is elicited by brief incremental stimuli presented against steady backgrounds of increasing intensity. The results can be accounted for by mechanisms of response compression, modified by the effects of photopigment bleaching, which together set the gain of the system at each background level, while also making the response nearly linear over a significant range of intensities above and below that of each adapting stimulus.
An
E. coli
Ribonucleoprotein Containing 4.5
S
RNA Resembles Mammalian Signal Recognition Particle
Authors: Poritz Mark A. , Bernstein Harris D. , Strub Katharina , Zopf Dieter , Wilhelm Heike , Walter Peter
Published: October 2006

The signal recognition particle (SRP) plays a central role in directing the export of nascent proteins from the cytoplasm of mammalian cells. An SRP-dependent translocation machinery in bacteria has not been demonstrated in previous genetic and biochemical studies. Sequence comparisons, however, have identified (i) a gene in
Escherichia coli
(
ffh
) whose product is homologous to the 54-kilodalton subunit (SRP54) of SRP, and (ii) an RNA encoded by the
ffs
gene (4.5
S
RNA) that shares a conserved domain with the 7
S
L RNA of SRP. An antiserum to Ffh precipitated 4.5
S
RNA from
E. coli
extracts, implying that the two molecules reside in a complex. The 4.5
S
RNA can also bind to SRP54 and can replace 7
S
L RNA in an enzymatic assay. The product of a dominant mutation in the
ffs
gene (4.5
S
RNA
dl1
) is also coprecipitated by the antiserum to Ffh protein and is lethal when expressed from an inducible promoter. After induction of 4.5
S
RNA
dl1
, the earliest observed phenotype was a permanent induction of the heat shock response, suggesting that there was an accumulation of aberrant proteins in the cytoplasm. Late after induction, translocation of β-lactamase was impaired; this may be an indirect effect of heat shock, however, because translocation of ribose binding protein or of the porin, OmpA, was unaffected. An unusual separation of the inner and outer membranes, suggestive of a defect in cell envelope, was also observed. Protein synthesis did not cease until very late, an indication that 4.5
S
RNA probably does not have a direct role in this process.
Cystic Fibrosis Transmembrane Conductance Regulator: Nucleotide Binding to a Synthetic Peptide
Authors: Thomas Philip J. , Shenbagamurthi P. , Ysern Xavier , Pedersen Peter L.
Published: October 2006

Multiple mutations in the gene responsible for cystic fibrosis are located within a region predicted to encode a nucleotide-binding fold in the amino terminal half of the cystic fibrosis transmembrane conductance regulator protein. A 67-amino acid peptide (P-67) that corresponds to the central region of this putative nucleotide binding site was chemically synthesized and purified. This peptide bound adenine nucleotides. The apparent dissociation constants (
K
d
's) for the trinitrophenyl (TNP) adenine nucleotides, TNP-adenosine triphosphate, TNP-adenosine diphosphate, and TNP-adenosine monophosphate, were 300 nanomolar, 200 nanomolar, and greater than 1 micromolar, respectively. The
K
d
for adenosine triphosphate was 300 micromolar. Circular dichroism spectroscopy was used to show that P-67 assumes a predominantly β sheet structure in solution, a finding that is consistent with secondary structure predictions. On the basis of this information, the phenylalanine at position 508, which is deleted in approximately 70 percent of individuals with cystic fibrosis, was localized to a β strand within the nucleotide binding peptide. Deletion of this residue is predicted to induce a significant structural change in the β strand and altered nucleotide binding.
Retronphage φR73: an
E. coli
Phage That Contains a Retroelement and Integrates Into a tRNA Gene
Authors: Inouye Sumiko , Sunshine Melvin G. , Six Erich W. , Inouye Masayori
Published: October 2006

Some strains of
Escherichia coli
contain retroelements (retrons) that encode genes for reverse transcriptase and branched, multicopy, single-stranded DNA (msDNA) linked to RNA. However, the origin of retrons is unknown. A P4-like cryptic prophage was found that contains a retroelement (retron Ec73) for msDNA-Ec73 in an
E. coli
clinical strain. The entire genome of this prophage, named φR73, is 12.7 kilobase pairs and is flanked by 29-base pair direct repeats derived from the 3′ end of the selenocystyl transfer RNA gene (
selC
). P2 bacteriophage caused excision of the φR73 prophage and acted as a helper to package φR73 DNA into an infectious virion. The newly formed φR73 closely resembled P4 as a virion and in its lytic growth. Retronphage φR73 lysogenized a new host strain, reintegrating its genome into the
selC
gene of the host chromosome and enabling the newly formed lysogens to produce msDNA-Ec73. Hence, retron Ec73 can be transferred intercellularly as part of the genome of a helper-dependent retronphage.
Hydrocortisone-Mediated Increase of Norepinephrine Uptake by Brain Slices
Authors: Maas James W. , Mednieks Maija
Published: October 2006

Slices of cerebral cortex from the adult rat were incubated with and without hydrocortisone succinate, and their subsequent uptake of isotopically labeled norepinephrine was measured. Preincubation with hydrocortisone resulted in a statistically significant increase in the amount of exogenous norepinephrine taken up by the slices. Preincubation with corresponding concentrations of sodium succinate was without effect. The principal effect of the hydrocortisone-mediated increase in norepinephrine concentration is apparently on an active transport mechanism.
Competition between Species: Frequency Dependence
Authors: Ayala Francisco J.
Published: October 2006

Whether two species competing for the same limited resources can stably coexist has been subject to controversy for several decades. The relative fitnesses of two species of
Drosophila
under competition in laboratory populations are shown to be inversely related to the relative frequencies of these species. This frequency-dependent fitness leads to a stable coexistence of the two species in spite of their competition for limited resources.
Laser Stimulation of Nerve Cells in
Aplysia
Authors: Fork Richard L.
Published: October 2006

Laser radiation at 488 nanometers selectively stimulates neurons in the abdominal ganglion of the marine mollusk
Aplysia californica
. The laser radiation can be scanned over the surface of the ganglion and can be effectively utilized in mapping cellular interconnections. The laser appears to cause these changes through some mechanism other than damage.
Structural Determinants of Ion Flow Through Recombinant Glutamate Receptor Channels
Authors: Verdoorn Todd A. , Burnashev Nail , Monyer Hannah , Seeburg Peter H. , Sakmann Bert
Published: October 2006

Functional glutamate receptors (GluRs) were transiently expressed in cultured mammalian cells from cloned complementary DNAs encoding GluR-A, -B, -C, or -D polypeptides. The steady-state current-voltage (
I-V
) relations of glutamate- and kainate-induced currents through homomeric channels fell into two classes: channels composed of either the GluR-A, -C, and -D subunits showed doubly rectifying
I-V
curves, and channels composed of the GluR-B subunits displayed simple outward rectification. The presence of GluR-B subunits in heteromeric GluRs determined the
I-V
behavior of the resulting channels. Site-directed mutagenesis identified a single amino acid difference (glutamine to arginine) in the putative transmembrane segment TM2 responsible for subunit-specific
I-V
relationships. The properties of heteromeric wild-type and mutant GluRs revealed that the dominance of GluR-B is due to the arginine residue in the TM2 region.
Effect of Deleting the R Domain on CFTR-Generated Chloride Channels
Authors: Rich Devra P. , Gregory Richard J. , Anderson Matthew P. , Manavalan Parthasarathy , Smith Alan E. , Welsh Michael J.
Published: October 2006

The cystic fibrosis transmembrane conductance regulator (CFTR), which forms adenosine 3′,5′-monophosphate (cAMP)-regulated chloride channels, is defective in patients with cystic fibrosis. This protein contains two putative nucleotide binding domains (NBD1 and NBD2) and an R domain. CFTR in which the R domain was deleted (CFTRΔR) conducted chloride independently of the presence of cAMP. However, sites within CFTR other than those deleted also respond to cAMP, because the chloride current of CFTRΔR increased further in response to cAMP stimulation. In addition, deletion of the R domain suppressed the inactivating effect of a mutation in NBD2 (but not NBD1), a result which suggests that NBD2 interacts with the channel through the R domain.
Stimulation of Protein Tyrosine Phosphorylation by NMDA Receptor Activation
Authors: Bading Hilmar , Greenberg Michael E.
Published: October 2006

The
N
-methyl-D-aspartate (NMDA) receptor, a subtype of glutamate receptors, plays a key role in synaptic plasticity in the nervous system. After NMDA receptor activation, calcium entry into the postsynaptic neuron is a critical initial event. However, the subsequent mechanisms by which the NMDA receptor signal is processed are incompletely understood. Stimulation of cultured rat hippocampal cells with glutamate resulted in the rapid and transient tyrosine phosphorylation of a 39-kilodalton protein (p39). Tyrosine phosphorylation of p39 was triggered by the NMDA receptor and required an influx of Ca
2+
from the extracellular medium. Because p39 was found to be highly related or identical to the microtubule-associated protein 2 kinase, the NMDA receptor signal may be processed by a sequential activation of protein kinases.
Residues of Total Mercury and Methylmercuric Salts in Lake Trout as a Function of Age
Authors: Bache C. A. , Gutenmann W. H. , Lisk D. J.
Published: October 2006

An analysis of the concentrations of total mercury and methylmercuric salts in lake trout of precisely known ages from 1 to 12 years has been carried out. The concentrations of both total mercury and methylmercury increased with the age of the fish. The proportion of methylmercury to total mercury also increased with age.
Batrachotoxin: Chemistry and Pharmacology
Authors: Albuquerque E. X. , Daly J. W. , Witkop B.
Published: October 2006

Batrachotoxin has been shown to be a pyrrolecarboxylic ester of a novel steroidal base with unique and selective actions on a variety of electrogenic membranes. The effects of batrachotoxin in neuromuscular preparations both pre- and postsynaptically, in nerve axons, in superior cervical ganglion, in heart Purkinje fibers, and in brain slices appear to be due to the selective and irreversible increase in permeability of membranes to sodium ions. The subsequent effects of this increase in Na
+
permeability evoked by batrachotoxin—such as membrane depolarization, enhanced spontaneous transmitter release, muscle contracture, and enhanced formation of cyclic AMP in brain slices—may be blocked reversibly by tetrodotoxin.
Electrophysiological Observations in Normal and Dystrophic Chicken Muscles
Authors: Albuquerque Edson X. , Warnick Jordan E.
Published: October 2006

Intracellular recordings were made on the fast posterior latissimus dorsi muscles of normal and dystrophic chickens. In the dystrophic chickens, the rate of rise of the action potential was decreased. With repetitive indirect stimulation, the action potentials decreased in size and disappeared; only an end-plate potential remained. Membrane resistance, membrane capacitance, and duration of miniature end-plate potentials were increased. A decrease in sodium permeability may be in part responsible for the observed alterations in the electrical properties of the nerve terminal and postsynaptic muscle membrane.
Folding of Circularly Permuted Transfer RNAs
Authors: Pan Tao , Gutell Robin R. , Uhlenbeck Olke C.
Published: October 2006

All of the ribose-phosphate linkages in yeast tRNA
Phe
that could be cleaved without affecting the folding of the molecule have been determined in a single experiment. Circular permutation analysis subjects circular tRNA molecules to limited alkaline hydrolysis in order to generate one random break per molecule. Correctly folded tRNAs were identified by lead cleavage at neutral pH, a well-characterized reaction that requires proper folding of tRNA
Phe
. Surprisingly, most of the circularly permuted tRNA molecules folded correctly. This result suggests that the tRNA folding motif could occur internally within other RNA sequences, and a computer search of Genbank entries has identified many examples of such motifs.
Biphasic Feeding Response in a Sea Anemone: Control by Asparagine and Glutathione
Authors: Lindstedt K. June
Published: October 2006

Two phases of the feeding response in the sea anemone
Anthopleura elegantissima
are controlled by different chemical activators. Asparagine controls the contraction and bending of tentacles which bring food to the mouth; reduced glutathione controls ingestion of food once it has contacted the mouth. A complete feeding response occurs only when both chemical activators are present.
C1̅ Inhibitor: Evidence for Decreased Hepatic Synthesis in Hereditary Angioneurotic Edema
Authors: Johnson A. Myron , Alper Chester A. , Rosen Fred S. , Craig John M.
Published: October 2006

Although the C1̅ inhibitor was detected in 5 to 10 percent of normal hepatic parenchymal cells by means of the immunofluorescent technique, none was seen in liver biopsies from two individuals with hereditary angioneurotic edema having low concentrations of C1̅ inhibitor in the serum. In contrast, the percentages of cells which reacted with fluorescent antiserums to C4 and transferrin were normal. These data suggest that in most subjects with hereditary angioneurotic edema, there is decreased synthesis of the C1̅ inhibitor but normal synthesis of C4, and that the disease results from this biosynthetic error.
Ammonium and Chloride Extrusion: Hyperpolarizing Synaptic Inhibition in Spinal Motoneurons
Authors: Lux H. D.
Published: October 2006

The reversal potential of postsynaptic inhibition shifts toward resting membrane potentials in cat spinal motoneurons after intravenous infusion of ammonium salts (1 to 3 millimoles per kilogram of body weight). Simultaneously, the depolarizing action of intracellularly injected chloride ions on the inhibitory membrane is enhanced and recovery therefrom is prolonged. Passive membrane properties remain unaltered. The results indicate a blocking of active extrusion of chloride which normally maintains a high ionic gradient for hyperpolarizing inhibition.
Subacute Sclerosing Panencephalitis: Isolation of Suppressed Measles Virus from Lymph Node Biopsies
Authors: Horta-Barbosa Luiz , Hamilton Rebecca , Wittig Barbara , Fuccillo David A. , Sever John L. , Vernon Mina Lee
Published: October 2006

Measles virus was isolated in mixed cultures of lymph node cells and HeLa cells. The agent was isolated by cocultivation from biopsy specimens of two of five patients with subacute sclerosing panencephalitis. The virus was identified by hemagglutination-inhibition, immunofluorescent, and neutralization tests. Biopsies from controls did not show evidence of measles virus.
Early Silurian Spore Tetrads from New York: Earliest New World Evidence for Vascular Plants?
Authors: Gray Jane , Boucot A. J.
Published: October 2006

Several taxa of abundant cutinized trilete spores from earliest Silurian shale in New York predate by almost an entire period vascular land plant megafossils. Paleoecological evidence suggests that these spores may represent vascular land or semiaquatic plants but a bryophytic origin cannot be precluded on the basis of spore characters. An algal origin is considered unlikely.
Reversible Osmotic Opening of the Blood-Brain Barrier
Authors: Rapoport Stanley I. , Hori Masaharu , Klatzo Igor
Published: October 2006

Reversible breakdown of the blood-brain barrier is produced by a class of electrolytes and nonelectrolytes which have little or no lipid solubility but which differ in chemical and ionic properties. These agents may osmotically shrink barrier cells, possibly the vascular endothelium, and reversibly open spaces between them. Lipid-soluble nonelectrolytes damage the barrier irreversibly.
Temporal Synergism of Corticosterone and Prolactin Controlling Gonadal Growth in Sparrows
Authors: Meier Albert H. , Martin Donn D. , MacGregor Robert
Published: October 2006

Gonadal growth was controlled in two avian species by corticosterone and prolactin injected daily at various times. Testicular growth was induced in photorefractory house sparrows (
Passer domesticus
) kept in continuous light by prolactin injected 4 or 8 hours after administration of corticosterone. Other temporal patterns were ineffective. Gonadal growth was also stimulated in photosensitive white-throated sparrows (
Zonotrichia albicollis
) kept in continuous light by prolactin injected 12 hours after administration of corticosterone. Daily injections of prolactin 8 hours after injection of corticosterone inhibited gonadal growth. The seasonal cycle of reproductive photorefractoriness and photosensitivity is controlled by a changing relation between the daily rhythms of plasma concentrations of corticosterone and prolactin.
Sporogonic Development of a Malaria Parasite in Vitro
Authors: Warburg Alon , Miller Louis H.
Published: October 2006

The sporogonic cycle of the avian malaria parasite
Plasmodium gallinaceum
was completed in vitro. Ookinetes (motile zygotes) were seeded onto a murine basement membrane-like gel (Matrigel) in coculture with
Drosophila melanogaster
cells (Schneider's L2). Transformation into oocysts as well as subsequent growth and differentiation were observed in parasites attached to Matrigel and depended on the presence of L2 cells. Sporozoites were first observed on day 10 in culture. Specific circumsporozoite protein antigenicity was identified in mature oocysts and in sporozoites. It is now possible to follow the entire life cycle of
Plasmodium
in vitro.
Iron- and Riboflavin-Dependent Metabolism of a Monoamine in the Rat in vivo
Authors: Symes Aston L. , Missala Krystyna , Sourkes Theodore L.
Published: October 2006

n
-Pentylamine enters into intermediary metabolism by the action of monoamine oxidase. [1-
14
C]Pentylamine injected into rats is rapidly converted to
14
CO
2
. The rate of catabolism decreases progressively in the course of nutritional iron deficiency, reaching about 60 percent of control values in 3 weeks. Feeding with iron yields control levels within 6 days. The catabolism of amyl alcohol, which shares a common pathway with
n
-pentylamine by way of valeric aldehyde, is not significantly affected by the deficiency. The results demonstrate that the maintenance of normal monoamine oxidase activity in vivo depends upon an adequate supply of dietary iron.
Synchrony and Flash Entrainment in a New Guinea Firefly
Authors: Hanson Frank E. , Case James F. , Buck Elisabeth , Buck John
Published: October 2006

Fireflies can duplicate both faster and slower rhythms of artificial light. Since the interval between the pacer signal and the firefly's flash of the next cycle approximates the firefly's normal free-run period, it is suggested that the pacer signal resets the flash-timing oscillator in the brain, thus providing a mechanism for synchronization.
Riboflavin Photosensitized Oxidation of 2,4-Dichlorophenol: Assessment of Possible Chlorinated Dioxin Formation
Authors: Plimmer Jack R. , Klingebiel Ute I.
Published: October 2006

Dimeric products are formed by riboflavin-sensitized photooxidation of 2,4-dichlorophenol. The products of this reaction were examined to determine whether chlorinated dibenzo-
p
-dioxins could be formed from chlorophenols in water by the action of light of wavelengths greater than 280 nanometers. Dimers are formed by union of phenoxy radicals through carbon-carbon or carbon-oxygen bonds. 4,6-Dichloro-2-(2,4-dichlorophenoxy)phenol was obtained in greater quantity than other dimers. Products were characterized by combined gas chromatography and mass spectrometry. Chlorinated dibenzo-
p
-dioxins which could result from ring closure of a 2-phenoxyphenol derivative were not detected in the products of photolysis. The failure to detect chlorinated dibenzo-
p
-dioxins may result from the rapid photolytic breakdown of the lower chlorinated dibenzo-
p
-dioxins. Under environmental conditions, dioxins are unlikely products of the lower chlorinated phenols or phenoxyalkanoic acids.
Cation Disorder in Shocked Orthopyroxene
Authors: Dundon R. W. , Hafner S. S.
Published: October 2006

The distribution of magnesium and iron over the
M
1 and
M
2 positions in Bamle enstatite shocked at 1 megabar is highly disordered. It corresponds to an equilibrium distribution of at least 1000°C. The distribution in samples shocked at 450 kilobars or less is undisturbed.
Junctions between Cancer Cells in Culture: Ultrastructure and Permeability
Authors: Johnson Ross G. , Sheridan Judson D.
Published: October 2006

Cell junctions between Novikoff hepatoma cells (N1S1-67) growing as small clumps or chains in suspension culture have been studied with ultrastructural, electrophysiological, and dye-injection techniques. Cells within clumps are commonly electrically coupled and can exchange dyes with a molecular weight of 332 to 500. Gap junctions and intermediate junctions are present, whereas true tight junctions and desmosomes are absent or very rare. This system should provide a useful model for studying the properties of "communicating" junctions.
Infrared Spectroscopy Experiment on the Mariner 9 Mission: Preliminary Results
Authors: Hanel R. A. , Conrath B. J. , Hovis W. A. , Kunde V. G. , Lowman P. D. , Pearl J. C. , Prabhakara C. , Schlachman B. , Levin G. V.
Published: October 2006

The Mariner 9 infrared spectroscopy experiment has provided good-quality spectra of many areas of Mars, predominantly in the southern hemisphere. Large portions of the thermal emission spectra are significantly affected by dust with a silicon oxide content approximately corresponding to that of an intermediate igneous rock, thus implying that Mars has undergone substantial geochemical differentiation. Derived temperature profiles indicate a warm daytime upper atmosphere with a strong warming over the south polar cap. Atmospheric water vapor is clearly observed over the south polar area and less strongly over other regions.
Control of Aggregation in
Dictyostelium discoideum
by an External Periodic Pulse of Cyclic Adenosine Monophosphate
Authors: Robertson Anthony , Drage David J. , Cohen Morrel H.
Published: October 2006

We have induced and controlled normal aggregation of
Dictyostelium discoideum
amoebas by electrophoretic release of pulses of cyclic adenosine monophosphate from a microelectrode. This has yielded information about the sequence of development of aggregation competences during interphase. We believe that modifications of the technique will have wide application in investigations of other developing systems.
Chemistry, Geochronology, and Petrogenesis of Lunar Sample 15555
Authors: Chappell B. W. , Compston W. , Green D. H. , Ware N. G.
Published: October 2006

Lunar sample 15555 is a mare type basalt generally similar in chemical composition to the Apollo 12 basalts. Sample 15555 is older than any Apollo 12 basalt but younger than the Apollo 14 basalts analyzed thus far.
Ethnic Differences in Alcohol Sensitivity
Authors: Wolff Peter H.
Published: October 2006

Japanese, Taiwanese, and Koreans, after drinking amounts of alcohol that have no detectable effect on Caucasoids, respond with a marked facial flushing and mild to moderate symptoms of intoxication. Group differences are present at birth, and are probably related to variations in autonomic reactivity.
Wound-Induced Proteinase Inhibitor in Plant Leaves: A Possible Defense Mechanism against Insects
Authors: Green T. R. , Ryan C. A.
Published: October 2006

Wounding of the leaves of potato or tomato plants by adult Colorado potato beetles, or their larvae, induces a rapid accumulation of a proteinase inhibitor throughout the plants' tissues that are exposed to air. This effect of insect damage can be simulated by mechanically wounding the leaves. The transport of a factor out of damaged leaves takes place rapidly after the wound is inflicted and the levels of proteinase inhibitor, in both damaged and adjacent leaves, rises strikingly within a few hours. The rapid accumulation of a powerful inhibitor of major intestinal proteinases of animals in response to wounding of the leaves is probably a defense mechanism.
Ultrathin Carbon Support Films for Electron Microscopy
Authors: Williams Robley C. , Glaeser Robert M.
Published: October 2006

Carbon support films only 4 to 6 angstroms thick have been made for use in electron microscopy. The determination of their thickness is based on geometrical calculation, electron scattering measurements, and elemental microanalysis.
Δ
9
-Tetrahydrocannabinol and Ethyl Alcohol: Evidence for Cross-Tolerance in the Rat
Authors: Newman L. Michael , Lutz Michael P. , Gould Michael H. , Domino Edward F.
Published: October 2006

Rats trained in a one-way avoidance situation were made tolerant to the depressant effects of Δ
9
-tetrahydrocannabinol. Ethyl alcohol (3.2 grams per kilogram, intraperitoneally) did not greatly affect rats that were tolerant to Δ
9
-tetrahydrocannabinol but depressed the behavior of nontolerant rats. Rats made tolerant to ethyl alcohol were less affected by Δ
9
-tetrahydrocannabinol.
Measurement Structures and Psychological Laws
Authors: Krantz David H.
Published: October 2006

Empirical laws in psychology may be based on physical measurements (for example, voltages, times), counting, ordering, or just classifying. It is a pointless, though widespread practice to use a physical measure or a count as a "definition" of a psychological variable; this practice obscures the fact that all one has done is measured a physical variable, or counted. What is important are the empirical laws that are established by use of such quantitative or qualitative observations. Some kinds of empirical relations and laws yield measurement structures, akin to the qualitative structures underlying fundamental measurement in physics. Measurement structures are empirical structures that can be described most simply by introduction of a new numerical function; such a function is a new measure, and is typically interpreted as measuring some particular psychological variable.

Measurement structures, formulated abstractly, sometimes provide valuable tools for formulating new empirical hypotheses to be tested; but in many instances, other kinds of theory may be more appropriate. The main focus of research ought always to be the discovery of simple laws; these may or may not lead to new measures.
Capillary Tube Scanning Applied to Cell Growth Kinetics
Authors: Braslow Nelson M. , Bowman Robert L.
Published: October 2006

We have developed an optical scanning instrument which may become a valuable aid in a variety of cell studies. Cell multiplication can be readily monitored with the instrument. By varying the chemical environment in which the cells are tested, questions of research and clinical interest may be quickly and conveniently answered. It appears possible to investigate the chemotherapeutic value of experimental agents, and to scan the sensitivity of a given population of neoplastic cells to a variety of chemotherapeutic agents at several concentrations. The optical scanning system may also be used to investigate certain metabolic pathways of cells in tissue culture, to determine drug resistance, and to assess the effects of medium composition on cell growth.

Our studies of BrdU resistance in mouse lymphoma cells were done primarily to demonstrate the potential of this optical scanning method, and we do not intend to continue the cytokinetic studies at present. We trust that others will be stimulated to investigate further applications of this instrumental approach to problems in cell biology.
Glycerol Phosphate Shuttle in Virus-Transformed Cells in Culture
Authors: Bissell Mina J. , Rambeck Walter A. , White Rodney C. , Bassham James A.
Published: October 2006

The glycerol phosphate shuttle is shown not only to be present and functional in virus-transformed cells, but its level is higher than in normal cells in culture. The increased aerobic glycolysis that has been demonstrated for these cells after transformation, therefore, is not due to an impairment of hydrogen transfer pathways.
Length-Force Relation of Calcium Activated Muscle Fibers
Authors: Schoenberg Mark , Podolsky Richard J.
Published: October 2006

Calcium activated skinned frog muscle fibers develop a large relative force at a sarcomere length of 1.0 micrometer. Since the normal myofilament lattice is perturbed at this length, regularity of the lattice does not appear to be an important factor in the contraction mechanism.
Magnetic Compass of European Robins
Authors: Wiltschko Wolfgang , Wiltschko Roswitha
Published: October 2006

The magnetic compass of European robins does not use the polarity of the magnetic field for detecting the north direction. The birds derive their north direction from interpreting the inclination of the axial direction of the magnetic field lines in space, and they take the direction on the magnetic north-south axis for "north" where field lines and gravity vector form the smaller angle.
Induction of Pulmonary Edema and Emphysema in Cattle and Goats with 3-Methylindole
Authors: Carlson J. R. , Yokoyama M. T. , Dickinson E. O.
Published: October 2006

Microorganisms from rumen converted L-tryptophan and indoleacetic acid to 3-methylindole in vitro. Oral doses of 3-methylindole caused interstitial pulmonary edema and emphysema in cattle and goats. Intravenous infusion of this metabolite also induced pulmonary disease in cattle. These results demonstrate than an end product of ruminal fermentation of tryptophan can induce acute pulmonary disease in cattle and goats.
Neuromuscular Transmission: Inhibition by Manganese Ions
Authors: Meiri U. , Rahamimoff R
Published: October 2006

Manganese ions are potent blocking agents of synaptic transmission at the neuromuscular junction in the frog. The main site of action is the presynaptic nerve terminal, where the ions decrease the amount of transmitter liberated by a nerve impulse. The inhibition produced by manganese is reversible.
A Mutation Influencing the Transportation of Manganese, L-Dopa, and L-Tryptophan
Authors: Cotzias George C. , Tang Lily C. , Miller Samuel T. , Sladic-Simic D. , Hurley Lucille S.
Published: October 2006

Transportation of manganese, L-dopa, and L-tryptophan was slower through the tissues of intact pallid mice than through those of black C57Bl/6J mice, presumably because of the influence of the gene
pallid
.
Sex Differences in Electric Signaling in an Electric Fish
Authors: Hopkins Carl D.
Published: October 2006

The electric discharge of
Sternopygus macrurus
is distinctly different from the discharges of ten sympatric species of electric fish in Guyana, South America.
Sternopygus
is the first known example of a fish with sexually different electric discharges. Males and females differ in the steady-state frequency of their discharges, and males produce variations in their discharge during courtship. Playback experiments demonstrate that species and sex differences in electric discharges have communicative significance.
Morphine-3-Succinyl—Bovine Serum Albumin: An Immunogenic Hapten-Protein Conjugate
Authors: Wainer Bruce H. , Fitch Frank W. , Rothberg Richard M. , Fried Josef
Published: October 2006

Morphine-3-hemisuccinate was synthesized by reaction of morphine with succinic anhydride. This compound was conjugated to bovine serum albumin by the mixed anhydride method, and the degree of conjugation was determined by base hydrolysis of the conjugate, extraction, and measurement of free morphine. An average of 6.5 molecules of morphine were conjugated to each molecule of protein. Eleven rabbits immunized with varying doses of the conjugate were producing antibody 8 weeks later, as determined by a modification of the ammonium sulfate method, which measures primary binding of antigen by antibody.
Behavioral Thermoregulation by Fishes: A New Experimental Approach
Authors: Neill William H. , Magnuson John J. , Chipman Gerald G.
Published: October 2006

Electronic equipment allows fishes, by their spatial movements, to regulate the temperature in experimental tanks. Swimming into warmer water causes the temperature of the entire tank to increase; conversely, swimming into cooler water causes the temperature to decrease. The technique may be adapted for studying simultaneous behavioral regulation of temperature and nonthermal factors.
Neurotransmitter Regulation of Adenosine 3′,5′-Monophosphate in Clonal Nerve, Glia, and Muscle Cell Lines
Authors: Schubert David , Tarikas Helgi , LaCorbiere Monique
Published: October 2006

Norepinephrine increases the intracellular level of adenosine 3′,5′-monophosphate (cyclic AMP) in clonal cell lines of nerve, glia, smooth muscle, and skeletal muscle. The largest response is in skeletal muscle, where the cyclic nucleotide concentration is elevated more than 500-fold. Glia and muscle cells, but not nerve cells, respond to dopamine with increased cyclic AMP accumulation. This response appears to be mediated through a beta-adrenoreceptor.
Indole-3-Acetic Acid in-Human Cerebrospinal Fluid: Identification and Quantification by Mass Fragmentography
Authors: Bertilsson Leif , Palmér Lena
Published: October 2006

Indole-3-acetic acid has been identified in human cerebrospinal fluid by the gas chromatographic-mass spectrometric technique called mass fragmentography. A specific and sensitive method for quantitative determination of indole-3-acetic acid down to 2 nanograms per milliliter of cerebrospinal fluid has been developed. Samples of cerebrospinal fluid from 24 patients with depression contained 6.1 ± 3.1 (range 2.6 to 15.8) nanograms of indole-3-acetic acid per milliliter.
Pitting Function of the Spleen in Malaria: Ultrastructural Observations
Authors: Schnitzer Bertram , Sodeman Thomas , Mead Michael L. , Contacos Peter G.
Published: October 2006

Ultrastructural studies of spleens from monkeys infected with
Plasmodium knowlesi
suggest that the spleen removes or "pits" malaria parasites from red cells. This function may explain the presence of nonparasitized spherocytic erythrocytes in the peripheral blood and may in part account for the discrepancy between the excessive hemolysis and the number of parasitized erythrocytes in animals with experimentally induced malaria.
Mercury Vapor Concentrations inside Buildings
Authors: Foot Robert S.
Published: October 2006

The concentrations of elemental gaseous mercury in several homes, offices, and laboratories in the Dallas area have been measured. The values are substantially higher than the ambient natural background concentration, about 3 nanograms of mercury per cubic meter of air in San Francisco, Dallas, and Washington, D.C.
Nitrogen Excretion in Cockroaches: Uric Acid Is Not a Major Product
Authors: Mullins D. E. , Cochran D. G.
Published: October 2006

Thin-layer chromatographic and enzymatic spectrophotometric analyses have failed to detect uric acid in fecal extracts from American cockroaches on specified diets. Uric acid appears in the excreta when it is a dietary constituent, although most of it is apparently absorbed and stored internally. Surprisingly, ammonia is a major excretory product.
Acrosomal Proteinase and Proteinase Inhibitor of Human Spermatozoa
Authors: Zaneveld L. J. D. , Dragoje B. M. , Schumacher G. F. B.
Published: October 2006

The acrosomal proteinase of human spermatozoa was characterized and differs from other human proteinases. The enzyme has optimal activity at
p
H 8.0, is inactive below
p
H 5.0 or above
p
H 10.5, requires calcium for maximum activity, hydrolyzes fibrinogen, gelatin, and benzoylarginine ethyl ester, and is inhibited by various synthetic and natural proteinase inhibitors. The molecular weight was estimated to be 30,000. Human spermatozoa also possess a proteinase inhibitor that is similar to one of the proteinase inhibitors from human seminal plasma.
Body Temperature ofDermochelys coriacea: Warm Turtle from Cold Water
Authors: Frair Wayne , Ackman R. G. , Mrosovsky N.
Published: October 2006

The deep body temperature of a leatherback turtle,Dermochelys coriacea, taken out of cold water, was 18°C above the water temperature. A large size favoring heat retention from muscular activity is probably responsible for this differential. Cooling rates (k) in water, measured on a second animal, were in the order of 0.001°C per minute per degree of difference between body and ambient temperature.
A New, Long-Lasting Competitive Inhibitor of Angiotensin
Authors: Türker R. K. , Hall M. M. , Yamamoto M. , Sweet C. S. , Bumpus F. M.
Published: October 2006

An analog of angiotensin II, [Sar
1
, Ile
8
]-angiotensin II, has a potent and long-lasting competitive antagonistic effect against angiotensin II when tested for its myotropic action on the isolated rabbit aorta and for its effect on blood pressure in anesthetized cats and dogs. Compared to [Ile
8
]-angiotensin II, the new analog has equal antagonistic potency on the isolated system but a much greater potency in vivo. It is assumed that sarcosine in position 1 protects the peptide against enzymatic degradation and enhances its half-life. This study demonstrates that the modification in both positions 1 and 8 are important for the in vivo antagonistic potencies of angiotensin analogs.
Choline: High-Affinity Uptake by Rat Brain Synaptosomes
Authors: Yamamura Henry I. , Snyder Solomon H.
Published: October 2006

Synaptosomes from rat brain accumulate choline by two kinetically distinct processes, a high-affinity uptake system [Michaelis constant (
K
m
) = 1 × 10
-6
M
], and a low-affinity system (
K
m
= 9 × 10
-5
M
). The high-affinity uptake system requires sodium, and is associated with considerable formation of acetylcholine. The low-affinity uptake system is less dependent on sodium, and does not appear to be associated with a marked degree of acetylcholine formation. The high-affinity choline uptake appears to represent selective choline accumulation by cholinergic neurons.
Effect of Colchicine, Colcemid, and Vinblastine on the Agglutination, by Concanavalin A, of Transformed Cells
Authors: Yin Helen H. , Ukena Thomas E. , Berlin Richard D.
Published: October 2006

The sensitivity of transformed 3T3 fibroblasts to agglutination by concanavalin A is reduced by alkaloids that bind specifically to protein subunits of microtubules.
Lunar Topography: First Radar-Interferometer Measurements of the Alphonsus-Ptolemaeus-Arzachel Region
Authors: Zisk S. H.
Published: October 2006

Radar interferometry is a new technique for accurately measuring the topography of the lunar surface from the earth. Measurements have been made with this technique of an area including the craters Ptolemaeus, Alphonsus, and Arzachel and a portion of Mare Nubium. There is evidence for a late episode of volcanism that partially filled two of the craters through a crustal fault of Imbrian origin. Several other features of the topography, particularly those coinciding with local gravitational anomalies, can be correlated with flow events.