bluuebunny/crossref_metadata_2025 huggingface dataset:
A community-based wildlife survey: the knowledge and attitudes of residents of suburban Brisbane, with a focus on bandicoots
Authors: FitzGibbon Sean I. , Jones Darryl N.
Published: May 2006

Within the expanding city of Brisbane in south-east Queensland, numerous fragments of native and regrowth vegetation are scattered across the largely urbanised landscape. These fragments provide refuge to a great diversity of native wildlife, and provide residents with the opportunity to experience nature on their doorstep. To assess the diversity and abundance of this wildlife, recent changes in these parameters, and the value of wildlife and bushland fragments to residents of Brisbane, a questionnaire survey was distributed to 300 households each located adjacent to one of 38 urban bushland fragments. A total of 172 surveys (57%) were returned, producing 768 records of 83 fauna species, dominated by birds and mammals; bandicoots were widely reported from the 38 fragments. Several historical records provided evidence of recent local extinctions within fragments, highlighting the continuing declines in various species of native wildlife within Brisbane. Several human–wildlife conflicts were identified, but overall residents were tolerant of such conflicts. Bandicoots were disliked by a small minority (3%) of residents owing to the holes they dig in lawns and gardens in search of food, and their potential as vectors of ticks. Most respondents expressed an appreciation for the presence of native wildlife (96%) and bushland fragments (97%) in their local area, emphasising the importance of incorporating human dimension values into the management of this urban biodiversity.
Home range, habitat selection and diet of foxes (Vulpes vulpes) in a semi-urban riparian environment
Authors: White John G. , Gubiani Robert , Smallman Nathalie , Snell Kelly , Morton Anne
Published: May 2006

Between 2000 and 2002 the home range, habitat selection and diet of foxes were examined in the Dandenong Creek Valley, Melbourne, Australia. The mean home range was 44.6 ha (range 19.2–152.6 ha). A significant selection towards blackberry and gorse used as diurnal shelter was found during the day with an active avoidance of less structurally complex vegetation types. Although there was obvious selection of certain habitats, the diet of the foxes was highly general and opportunistic and thus offers little potential as a factor to manipulate in order to reduce fox abundance. Given the strong preference for blackberry and gorse as a shelter resource, a habitat-manipulation strategy is suggested whereby patches of blackberry and gorse are removed and replaced with less structurally complex vegetation. Such a strategy has the potential to influence the density of foxes in semi-urban riparian environments such as those discussed in this study.
A peptide based on the complementarity-determining region 1 of an autoantibody ameliorates lupus by up-regulating CD4+CD25+cells and TGF-β
Authors: Sharabi Amir , Zinger Heidy , Zborowsky Maya , Sthoeger Zev M. , Mozes Edna
Published: May 2006

Systemic lupus erythematosus is an autoimmune disease characterized by autoantibodies and systemic clinical manifestations. A peptide, designated hCDR1, based on the complementarity-determining region (CDR) 1 of an autoantibody, ameliorated the serological and clinical manifestations of lupus in both spontaneous and induced murine models of lupus. The objectives of the present study were to determine the mechanism(s) underlying the beneficial effects induced by hCDR1. Adoptive transfer of hCDR1-treated cells to systemic lupus erythematosus-afflicted (NZB×NZW)F1female mice down-regulated all disease manifestations. hCDR1 treatment up-regulated (by 30–40%) CD4+CD25+cells in association with CD45RBlow, cytotoxic T lymphocyte antigen 4, and Foxp3 expression. Depletion of the CD25+cells diminished significantly the therapeutic effects of hCDR1, whereas administration of the enriched CD4+CD25+cell population was beneficial to the diseased mice. Amelioration of disease manifestations was associated with down-regulation of the pathogenic cytokines (e.g., IFN-γ and IL-10) and up-regulation of the immunosuppressive cytokine TGF-β, which substantially contributed to the suppressed autoreactivity. TGF-β was secreted by CD4+cells that were affected by hCDR1-induced immunoregulatory cells. The hCDR1-induced CD4+CD25+cells suppressed autoreactive CD4+cells, resulting in reduced rates of activation-induced apoptosis. Thus, hCDR1 ameliorates lupus through the induction of CD4+CD25+cells that suppress activation of the autoreactive cells and trigger the up-regulation of TGF-β.
AN ELECTROPHYSIOLOGICAL ANALYSIS OF THE ACTION OF CARBOHYDRATES ON THE SUGAR RECEPTOR OF THE BLOWFLY
Authors: Omand Elizabeth , Dethier V. G.
Published: May 2006

Measurements of the taste thresholds of blowflies for a wide variety of carbohydrates, presented individually and in combination, showed that the stimulating effects of the compounds are not always additive. Both synergism and inhibition were observed. In order to gain some insight into the nature of the molecular events occurring in the receptor, it was deemed necessary to investigate synergism and inhibition in single receptors by electrophysiological methods.

This investigation revealed that mannose enhances the responses of the sugar receptor of the blowfly to aldose and aldose-derived sugars and reduces responses to the ketose sugars. Responses to fructose are enhanced by the presence of glucose and reduced by the addition of sorbose. Curves describing responses to the aldose and aldose-derived sugars over a wide range of concentrations have steep slopes and intersect the
x
axis at high concentration values. Curves relating to the ketoses have shallow slopes and lower intercepts. Two or more modes of action of carbohydrates on the sugar receptor are suggested by these data.
ON THE CONFORMATIONAL INSTABILITY OF HUMAN SERUM LOW-DENSITY LIPOPROTEIN: EFFECT OF TEMPERATURE
Authors: Scanu A. , Pollard H. , Hirz R. , Kothary K.
Published: May 2006

When examined by circular dichroism and ultraviolet spectroscopy, human serum low-density lipoprotein (LDL) and its delipidated product, apo LDL, exhibited reversible thermal changes. The more marked temperature sensitivity of apo LDL as compared to LDL was taken to support a constraining role by lipids on the observed structural instability of the apoprotein.
INTERRELATION BETWEEN ACTIVATION AND POLYMERIZATION IN GRAMICIDIN S BIOSYNTHESIS
Authors: Kleinkauf Horst , Gevers Wieland , Lipmann Fritz
Published: May 2006

The nucleic acid-independent biosynthesis of the peptide antibiotic gramicidin S results from the interaction of an enzyme bearing phenylalanine in activated form with a polyenzyme system charged with the other four component amino acids.

After reaction with ATP, magnesium, and any or all of its amino acid substrates, the polyenzyme system (mol wt 280,000) yields complexes containing AMP and the respective amino acids in the proportion of 1 to 2. Similar complexes are formed by another enzyme (mol wt 100,000) on incubation with ATP, magnesium, and L- or D-phenylalanine. The amino acids are probably bound as aminoacyl adenylates and then transferred to another function on the enzyme. Initiation of polymerization is achieved by combination of the two complexes. No ATP is needed for completion of synthesis, and free intermediates are not released. Enzyme organization and specificity are responsible for the ordering of the amino acid sequence.
REGULATION OF TASTE ACUITY BY THIOLS AND METAL IONS
Authors: Henkin R. I. , Bradley D. F.
Published: May 2006

The administration of thiol-containing drugs decreases taste acuity in man and animals. Copper (II) and zine (II) administration returns taste acuity to normal levels. The results suggest that (1) thiols and metals are in dynamic equilibrium in the metabolic net, (2) regulation of taste acuity occurs through changes which thiols and/or metals bring about in the conformation of a protein which lines the pore of the taste receptor and its membrane, and (3) thiols normally play an inhibitory role in taste.
GENETIC EVOLUTION OF BACTERIOPHAGE, I. HYBRIDS BETWEEN UNRELATED BACTERIOPHAGES P22 AND FELS 2
Authors: Yamamoto Nobuto
Published: May 2006

A new bacteriophage species, designated F22, was isolated from phage P22 stocks grown on
Salmonella typhimurium Q1
lysogenic for
Fels 2
at a frequency of less than 10
-11
. P22 has a very short tail with a hexagonal base plate and six spikes. Phage
Fels 2
is morphologically similar to
E. coli
T-even phages, having a long tail with a contractile sheath and carrying no genetic region related to P22. Phage F22 is morphologically and serologically indistinguishable from
Fels 2
, but carries the
c(c
1
,
c
2
, and
c
3
) markers of P22. The color markers
h
21
,
g
, and
m
3
of P22 do not appear in F22. Thus, F22 is evidently a recombinant between the unrelated bacteriophages P22 and
Fels 2
. The recombination between unrelated bacteriophages could play an important role in the evolution of bacteriophages.
INCREMENT OF AVERAGE FITNESS FOR MULTIPLE ALLELES
Authors: Li C. C.
Published: May 2006

When the various genotypes (

A
i
A
i
, A
i
A
i

) of an autosomal locus do not reproduce and contribute equally to the genetic composition of the next generation, we say that the “fitness” values of the genotypes are different, or that there is natural selection on the genotypes. Under natural selection, the average fitness for a random mating population increases with time until a stationary state is reached. This communication gives a general expression for the amount of increase of the average fitness per generation of selection. It was found that the amount of increase depends largely on the linear or additive component of the variance of the genotype fitness values and, to a lesser extent, on the dominance pattern for the values of heterozygote fitness relative to those of homozygote fitness.
ON THE MECHANISM OF CATALYSIS BY VITAMIN B
12
Authors: Brodie Jonathan D.
Published: May 2006

The requirements for alkylation and binding of nitrogenous ligands to cobalamins and cobinamides suggest that the central cobalt atom can exist either approximately in the plane of the corrin or axially displaced above this plane.

Distortion of the normal octahedral complex by axial displacement results when the dimethylbenzimidazole moiety of the coenzyme is prevented from coordinating with the cobalt. A general hypothesis of B
12
coenzyme catalysis that involves the potential of Co
III
-R
[unk]
and Co
I
-R
[unk]
transitions is proposed on the basis of these considerations.
DNA-DIRECTED PEPTIDE SYNTHESIS, VI. REGULATING THE EXPRESSION OF THE
Lac
OPERON IN A CELL-FREE SYSTEM
Authors: Zubay Geoffrey , Lederman Muriel
Published: May 2006

The operon model was proposed by Jacob and Monod in 1961 to explain the regulation of enzyme synthesis in bacteria. The model requires two genetic elements: a locus
i
which directs the synthesis of a repressor, and a locus called the operon which contains an operator gene and associated structural genes. The repressor is believed to stop RNA and enzyme synthesis by combining with the operator site. The inhibiting effect of the repressor is reversed by an inducer which interacts directly with the repressor. A DNA-dependent cell-free system has been developed for studying the regulation of the operon containing the gene for β-galactosidase enzyme. In this cell-free system, gene activity is indirectly measured by the synthesis of part of the enzyme. Qualitatively, the regulation of the operon in the cell-free system is similar to its regulation in intact cells. The cell-free system is used to advantage in experiments where it is desirable to use predetermined levels of repressor, operon, and inducer. Such quantitative studies suggest that two inducer molecules are most effective in removing the repressor from the gene.
RELATIONSHIP OF SLEEP, RESPIRATION, AND ANESTHESIA IN THE PORPOISE: A PRELIMINARY REPORT
Authors: McCormick James G.
Published: May 2006

The porpoise, an air-breathing mammal whose habits are entirely aquatic, presents special problems of respiration, sleep, and anesthesia. These problems have been studied in three species,
Tursiops truncatus, Lagenorhynchus obliquidens
, and
Phocoenoides dalli
.

The respiratory rhythm is unusual in that there is an extended pause—an apneustic plateau—between periods of expiration and inspiration. This rhythm has been observed under waking conditions, during sleep, and also when the animal is anesthetized. Two kinds of sleep behavior have been identified in
Tursiops
and
Lagenorhynchus
. In one of these, which is a light phase, the animal rests on the tank bottom for short periods, up to perhaps four minutes, and then comes to the surface to breathe. In a deeper phase the animal maintains itself at the surface for extended periods, breathing in an automatic fashion. In
Phocoenoides
no sleep behavior has been observed at any time.

I have examined the special theory of Dr. John C. Lilly regarding respiration and sleep in the porpoise, which is based upon the assumption that respiration in this animal is altogether voluntary, and from my observations have concluded that respiration in the porpoise can be automatic or can be brought under voluntary control, just as in other mammals. Also the anesthetization of this animal can be carried out safely by methods that correspond closely to those employed in other animals.
ULTRAVIOLET LIGHT ALTERATION OF CELLULAR DEOXYRIBONUCLEIC ACID
in vivo
Authors: Tan Eng M. , Stoughton Richard B.
Published: May 2006

DNA after irradiation with ultraviolet light was immunogenic in rabbits and elicited serum antibodies reacting specifically with UV-irradiated DNA. The serological reactions were demonstrated by immunodiffusion, complement fixation, and immunofluorescence. By immunofluorescence, antisera reacted with cell nuclei of irradiated tissue sections but not with unirradiated tissue. This method was employed to show the presence of UV lesions in tissues of mice exposed to UV light. UV lesions in DNA were present in nuclei of epidermal cells, and in heavily irradiated animals they were also detected in the corium immediately below the epidermis. The method is useful not only for directly demonstrating UV lesions of DNA but also for localizing such lesions in tissues.
FORMATION OF NEUROMUSCULAR JUNCTIONS IN EMBRYONIC CELL CULTURES
Authors: Shimada Yutaka , Fischman D. A. , Moscona A. A.
Published: May 2006

The formation of nerve-muscle junctions in monolayer cultures of embryonic muscle and spinal cord cells is described. Muscle-forming cells (myoblasts) from leg muscles of 12-day chick embryos were separated with trypsin and cultured on a collagen substrate for two days. Suspensions of ventral spinal cord cells from six-day chick embryos were then plated over the differentiating muscle cells. The cultures were subsequently examined by electron microscopy and in silver-stained light microscopic preparations. After 10-12 days in culture, irregular thickenings were observed along the nerve cell processes in contact with the muscle fibers which by that time had undergone advanced differentiation (myogenesis). By electron microscopy it was demonstrated that many of the nerve-muscle contacts had the characteristics of a synapse. Some aspects of the fine structure of these junctions are described. The possibilities raised by these findings with respect to innervation mechanisms and specificities in nerve-muscle interactions are briefly discussed.
THE PROTEINS OF BACTERIOPHAGE M13
Authors: Henry Timothy J. , Pratt David
Published: May 2006

Particles of the small filamentous coliphage M13 contain not only the major coat protein, which is the product of phage gene 8, but also a minor coat protein, the A protein, which is the product of gene 3. The A protein has a molecular weight of approximately 70,000 daltons, is present in one copy per virion, and is responsible for phage attachment to host cells. Also associated with purified M13 particles is a minor quantity of very small proteinaceous material, but its origin as a phage-coded product has not been demonstrated.

At least five phage-specific proteins, including the two coat proteins, are present in appreciable quantities in M13-infected cells. The principal phage protein synthesized is the product of gene 5, which is responsible for phage single-stranded DNA synthesis. This protein has a molecular weight of about 8,000 daltons. Its precise function in DNA synthesis is not yet known.

Phage proteins are synthesized at nearly normal rates in cells in which replication of phage double-stranded DNA is blocked by gene 2 mutations. This result suggests that the initial double-stranded DNA molecule serves as the principal template, perhaps the only template, for phage messenger RNA synthesis.
THE USE OF AN ETHIDIUM ANALOGUE IN THE DYE-BUOYANT DENSITY PROCEDURE FOR THE ISOLATION OF CLOSED CIRCULAR DNA: THE VARIATION OF THE SUPERHELIX DENSITY OF MITOCHONDRIAL DNA
Authors: Hudson Bruce , Upholt William B. , Devinny Joseph , Vinograd Jerome
Published: May 2006

The separation between open and closed circular DNA in buoyant CsCl gradients containing intercalating dyes depends on the superhelix density of the closed form. These separations are about 1.8 times larger with propidium iodide than with ethidium bromide. The superhelix densities of mitochondrial DNA from HeLa cells and
Lytechinus pictus
eggs appear to be about two thirds that of mitochondrial DNA from rat and rabbit liver.
A NEW RIBONUCLEOTIDE REDUCTASE SYSTEM AFTER INFECTION WITH PHAGE T4
Authors: Berglund Ove , Karlström Olle , Reichard Peter
Published: May 2006

The ribonucleotide reductase system of
Escherichia coli
B participates in the biosynthesis of DNA by reducing ribonucleoside diphosphates to the corresponding deoxyribonucleotides. The enzyme is regulated in a complicated way by allosteric modifiers. We now find that infection of
E. coli
with the bacteriophage T4 results in the appearance of a new ribonucleotide reductase system which shows a somewhat different pattern of regulation.

Two new proteins, provisionally called fractions A and B, were purified from the extracts of infected bacteria. The reduction of ribonucleotides by these two fractions required the addition of either dithiothreitol or TPNH and
E. coli
thioredoxin reductase. Mutants of T4 which lacked fraction A activity were obtained. Fraction B may be a virus-induced thioredoxin.
SUPPRESSION OF HEAVY AND LIGHT CHAIN ALLOTYPIC EXPRESSION IN HOMOZYGOUS RABBITS THROUGH EMBRYO TRANSFER
Authors: David Gary S. , Todd Charles W.
Published: May 2006

Homozygous suppression of allotypic specificities on both the heavy and light chains of rabbit immunoglobulin has been achieved by two methods involving embryo transfer. In the first method, young were transplanted into does producing antibody against an allotypic specificity homozygously present in the genome of the embryo. In this case, the suppression is caused by antibody transmitted
in utero
. In the second method, young from a nonimmunized surrogate mother lacking their allotypic genotype are injected neonatally with the antiallotype serum. Release from homozygous suppression appears to be achieved more readily than from heterozygous suppression.
ENDONUCLEASE II OF
E. coli
, I. ISOLATION AND PURIFICATION
Authors: Friedberg Errol C. , Goldthwait David A.
Published: May 2006

The isolation and purification of a new endonuclease of
E. coli
is described. This enzyme degrades alkylated DNA as assayed by a technique that requires double-strand scission. The enzyme also makes a limited number of single-strand breaks in native nonalkylated DNA.
SURFACE-SPECIFIC CHARACTERISTICS OF A CONTACT-INHIBITED CELL LINE CONTAINING THE SV40 VIRAL GENOME
Authors: Pollack Robert E. , Burger Max M.
Published: May 2006

A cytoagglutinin purified from wheat germ lipase agglutinated five related murine fibroblast cell lines in the order of their saturation densities. One cell line, which was transformed by the oncogenic papova virus SV40 but which had a low saturation density, agglutinated poorly. Preincubation of cells with trypsin increased their agglutinability, but trypsin made no cell line more agglutinable than the cell line with the highest saturation density.
HEPATITIS AND AUSTRALIA ANTIGEN: AUTOSOMAL RECESSIVE INHERITANCE OF SUSCEPTIBILITY TO INFECTION IN HUMANS
Authors: Blumberg B. S. , Friedlaender J. S. , Woodside Anita , Sutnick A. I. , London W. T.
Published: May 2006

Examples of inherited susceptibility to infection controlled by genes segregating at one or a small number of loci have been identified in lower animals. In this study we report data on what appears to be a similar situation in humans. “Australia antigen” is an antigen found in the sera of patients with acute and chronic hepatitis, and it may actually be a form of virus. It is very common in many tropical areas, and people in these areas having the antigen appear to be hepatitis carriers. The antigen is detected by immuno-diffusion in agar gel (Ouchterlony method). Individuals with the antigen are designated Au(1) and those without it Au(0). Family studies involving 1797 different individuals residing on the island of Bougainville are consistent with the hypothesis that susceptibility to chronic infection with the “antigen” is controlled by an autosomal recessive gene (
Au
1
). This confirms the conclusions previously arrived at from similar (but less extensive) studies on the island of Cebu. Individuals with this inherited susceptibility do not ordinarily have overt manifestations of hepatitis.

The sign test was used to determine family clustering. Segregation analysis was performed by the method of C. A. B. Smith. In the 41 Au(0) × Au(0) matings, 53.8 recessives were expected in the offspring and 56 were seen (0.7 >
p
> 0.5). In the Au(1) × Au(0) matings, 40.1 recessives were expected and 42 were seen (0.7 >
p
> 0.5). The Au(0) × Au(0) matings were also analyzed by the method of Li and Mantel, in which the recessive ratio of 0.25 is expected by the genetic hypothesis. The values observed were 0.2527 for the Bougainville study and 0.2461 for the Cebu study.
MULTIPLE PHENYLALANYL-TRANSFER RIBONUCLEIC ACID SYNTHETASE ACTIVITIES IN THE CYTOPLASM OF
Neurospora crassa
Authors: Kull Fredrick J. , Jacobson K. Bruce
Published: May 2006

Several tRNA's specific for a particular amino acid have been shown to exist in multiple, or isoaccepting, forms. There is considerable interest in establishing whether multiple aminoacyl-tRNA synthetases also exist. We present evidence that the cytoplasm of
Neurospora crassa
contains three chromatographically separable phenylalanyl-tRNA synthetases distinct from mitochondrial phenylalanyl-tRNA synthetase. In addition to differences in chromatographic properties the three enzymes exhibit different affinities, in Tris-Cl buffer, toward purified species of valine and alanine tRNA's isolated from
Escherichia coli
. The two major chromatographic fractions have very similar sedimentation characteristics, which makes a monomer-dimer relationship unlikely.
LEUCINE tRNA AND CESSATION OF
Escherichia coli
PROTEIN SYNTHESIS UPON PHAGE T2 INFECTION
Authors: Kano-Sueoka Tamiko , Sueoka Noboru
Published: May 2006

The involvement of tRNA in cellular differentiation has been tested by analyzing aminoacyl-tRNA of
Escherichia coli
after phage T2 infection. One or two minutes after infection, half of one of the five leucine tRNA components (Leu-tRNA
1
, CUG responding) undergoes a drastic structural change which leads to inactivity of both leucine acceptor activity and codon response. Whether or not the modification causes cessation of host protein synthesis without inhibiting phage-specific protein synthesis has been examined by analyzing polysome-bound leucine tRNA of
E. coli
before and after the phage infection. The results presented in this paper indicate that the amount of Leu-tRNA
1
used after infection was greatly reduced as compared to that used in noninfected cells. Studies of the
in vitro
protein-synthesizing system show that T2 mRNA rarely contains the CUG codon. A mechanism by which host mRNA translation is inhibited by the phage infection is proposed from this available information.
THE STIMULATORY EFFECT OF CYCLIC ADENOSINE 3′5′-MONOPHOSPHATE ON DNA-DIRECTED SYNTHESIS OF β-GALACTOSIDASE IN A CELL-FREE SYSTEM
Authors: Chambers Donald A. , Zubay Geoffrey
Published: May 2006

A cell-free system allowing for synthesis of β-galactosidase enzymatic activity has been developed. This system requires DNA containing the β-galactosidase gene, a cell-free extract of
Escherichia coli
bacteria, and the low-molecular-weight components necessary for transcription of the DNA and translation of the resulting messenger RNA. Such a system is useful for studying enzyme synthesis, as well as its regulation. The gene for β-galactosidase is part of the lac operon whose expression is under the control of the lac repressor. In whole cells the lac repressor inhibits almost all of the gene expression for β-galactosidase. In the cell-free system, we had previously been able to repress about half the gene expression. Adding cyclic adenosine 3′5′-monophosphate to the cell-free system improved the yield of β-galactosidase enzymatic activity by 8 to 30 times and the efficiency of repression from 50 to 95 per cent.
A FACTOR PROMOTING THE INITIATION OF GLOBIN SYNTHESIS IN A RABBIT RETICULOCYTE CELL-FREE SYSTEM
Authors: Fuhr Joseph E. , London Irving M. , Grayzel Arthur I.
Published: May 2006

The synthesis of globin has been studied in a reticulocyte cell-free system in which the initiation of polypeptide chain synthesis can proceed for as long as ten minutes of incubation. With this system, we have found evidence for a soluble factor in the reticulocyte that stimulates protein synthesis and appears to act by promoting initiation.
ENZYMATIC REPAIR OF DNA, I. PURIFICATION OF TWO ENZYMES INVOLVED IN THE EXCISION OF THYMINE DIMERS FROM ULTRAVIOLET-IRRADIATED DNA
Authors: Kaplan Joan C. , Kushner Sidney R. , Grossman Lawrence
Published: May 2006

Two nucleases that catalyze the excision of photoproducts from UV-irradiated DNA have been extensively purified from
M. luteus
(
M. lysodeikticus
). The first enzyme, an endonuclease, has been purified 5000-fold and is free of conflicting nuclease activities. It introduces single-strand breaks into irradiated DNA but does not act on native or single-stranded DNA. The purified enzyme is activated but not dependent on Mg
++
and has an approximate molecular weight of 15,000. Photoproduct excision is absolutely dependent on the second enzyme, a magnesium requiring exonuclease. This enzyme, which has been purified 1000-fold, is devoid of conflicting nucleases. It hydrolyzes irradiated and unirradiated denatured DNA at the same rate, but has no activity on RNA. It only acts on double-stranded DNA which has been both irradiated and pretreated with the endonuclease. The combined action of the endo- and exonuclease results in the quantitative removal of photoproduct regions from UV-irradiated DNA. Approximately five nucleotides are released for every single-strand incision.
THE SPECIFICITY OF INTERFERON INDUCTION IN CHICK EMBRYO CELLS BY HELICAL RNA
Authors: Colby Clarence , Chamberlin Michael J.
Published: May 2006

Treatment of chick embryo cells growing in culture with rI:rC and many other RNA-like polymers results in the induction of interferon. DEAE dextran is required to facilitate the uptake of the RNA into the cells. Interferon-inducing activity is found with a variety of double-stranded helical polynucleotides, provided that all the sugar residues are ribose. However, the effectiveness of different active polynucleotides at a given concentration varies considerably. The differences in activity among the various polynucleotides do not appear to reflect differences in the rate or amount of uptake into the cells or in the rate of intracellular breakdown. Thehigh degree of specificity of the induction process is consistent with the existence of a specific intracellular receptor site, which may be a protein.
A FACTOR THAT STIMULATES RNA SYNTHESIS BY PURIFIED RNA POLYMERASE
Authors: Davison J. , Pilarski L. M. , Echols H.
Published: May 2006

A protein factor, partially purified from
E. coli
, can stimulate some 30- to 50-fold the transcription of DNA by purified RNA polymerase. Evidence is presented suggesting that this stimulatory factor (designated M factor) exerts its effect before the RNA synthesis is initiated. The M factor is prepared from a crude ribosome fraction, but it does not require the presence of ribosomes for full activity.
GENETICS OF IMMUNOGLOBULIN κ-CHAINS: CHEMICAL ANALYSIS OF NORMAL HUMAN LIGHT CHAINS OF DIFFERING INV TYPES
Authors: Terry William D. , Hood Leroy E. , Steinberg Arthur G.
Published: May 2006

The relationship between Inv phenotype and the amino acid residue at position 191 in κ-type light polypeptide chains derived from the immunoglobulins of ten normal human sera was investigated. In each case, the amino acid present at position 191 correlated with the Inv phenotype of the individual. Kappa chains of seven Inv (—1,3) homozygotes had valine, while those of three Inv (1,3) heterozygotes had some chains with leucine and some with valine at this position. Genes encoding the Inv (1) and Inv (3) variants appear to be expressed equally in the heterozygous state, since approximately equal amounts of each gene product was recovered from heterozygotes.

The correlation between Inv phenotype and the amino acid residue present at position 191 is identical to that previously established for κ-type Bence-Jones proteins and myeloma protein light chains. These observations support the hypothesis that the valine-leucine interchange is encoded by two allelic forms of a single κ-chain common region gene.
POLYPEPTIDE CHAIN INITIATION IN
E. coli
: SULFHYDRYL GROUPS AND THE FUNCTION OF INITIATION FACTOR F
2
Authors: Mazumder Rajarshi , Chae Yung-Bog , Ochoa Severo
Published: May 2006

The activity of the chain initiation factor F
2
in promoting the messenger-dependent binding of formylmethionyl-transfer RNA (fMet∼tRNA
f
) to purified
E. coli
ribosomes is inhibited by sulfhydryl-binding reagents, such as N-ethylmaleimide or
p
-hydroxymercuribenzoate, but prior incubation with guanosine triphosphate (GTP) or with ribosomes largely prevents this inhibition. The effect of GTP suggests that it forms a complex with F
2
whereby “active” sulfhydryl groups become sheltered. Experiments on the time course of the binding reaction, with and without preincubation of F
2
with GTP, and gel filtration experiments with
3
H-labeled GTP lend support to this suggestion.
EXCITED-STATE TWO-PROTON TAUTOMERISM IN HYDROGEN-BONDED N-HETEROCYCLIC BASE PAIRS
Authors: Taylor Carl Al , El-Bayoumi M. Ashraf , Kasha Michael
Published: May 2006

The optical absorption and luminescence spectra of 7-azaindole and its doubly hydrogen-bonded dimer were investigated as a model for the study of electronic interactions in DNA base pairs. It is demonstrated that a biprotonic phototautomerism occurs in the dimer and in suitable ethanol solvates in fluid solvents but that the phenomenon is not observed in a rigid solvent matrix. The normal violet structured fluorescence of 7-azaindole monomer becomes a broad green fluorescence in the tautomer. It is shown that spectral band interchanges, excimer formation, excited-state single-proton transfer, and proton tunneling cannot account for the luminescence change, but that the molecular exciton effect facilitates the cooperative two-proton reversible transfer. It is proposed that biprotonic phototautomerism with molecular environmental sensitivity could provide a mechanism for the initial step in ultraviolet mutagenic effects in DNA.
MICROELECTRODE STUDIES ON THE MEMBRANE PROPERTIES OF ISOLATED MITOCHONDRIA
Authors: Tupper Joseph T. , Tedeschi Henry
Published: May 2006

The membrane potentials and resistances of isolated
Drosophila
mitochondria were measured after impalement with piezoelectric-driven microelectrodes. The potential is approximately +10 mv (positive inside), and the membrane resistance is approximately 2Ω·cm
2
under state 4 conditions. Experiments involving changes in external osmolality at constant ionic strength have suggested that the measured potential is across the mitochondrial semipermeable membrane. The mitochondria generally collapse seconds after impalement. In cases of successive impalements, potential and resistance values show slight decreases from the initial impalements.
RECESSIVE LETHALS: A NEW CLASS OF NONSENSE SUPPRESSORS IN
Escherichia coli
Authors: Soll Larry , Berg Paul
Published: May 2006

Two new nonsense suppressors in
Escherichia coli
were found in partial diploids carrying F′14 and were shown to be on the episome. These suppressors can exist only in cells which also contain the
su
-
allele, i.e.,
su
+
/
su
-
heterozygotes. Presumably the mutations cause an alteration of an essential cellular component, the complete loss of which is lethal.
Su
7, an amber suppressor, has an efficiency of 76 per cent and
su
8, an ochre suppressor, an efficiency of 4 per cent.
COMPARISON OF RAT LIVER MITOCHONDRIAL AND MICROSOMAL MEMBRANE PROTEINS
Authors: Schnaitman Carl A.
Published: May 2006

An improved method is described for dissolving membrane proteins and for resolving them by polyacrylamide gel electrophoresis. With this procedure, the inner mitochondrial membrane has been found to contain 23 different protein species and the outer membrane 12. Only one protein species appears to be common to the two membranes. Smooth and rough microsomal membranes contain 15 different proteins. The approximate molecular weight and relative amount of each protein species have been extrapolated from the gel patterns. The outer mitochondrial membrane and the smooth microsomal membrane contain at least three protein species that appear to be identical, suggesting that they possess a common origin.
THE BIOSYNTHESIS OF FERREDOXIN IN A CELL-FREE SYSTEM
Authors: Trakatellis Anthony C. , Schwartz Gerald
Published: May 2006

The investigation reported in this communication was concerned with the biosynthesis of ferredoxin in a cell-free system. A cell-free system, with the ability to incorporate amino acids into peptides and proteins, was developed from
Cl. pasteurianum
, and its requirements were established. After the incorporation of L-alanine-C
14
, ferredoxin-C
14
was isolated in crystalline form with the aid of added carrier ferredoxin. Amino acid analyses and absorption spectra strongly indicated that the isolated ferredoxin-C
14
, crystallized three times, was essentially free from impurities. Furthermore, experiments with Fe
59
strongly indicated that the iron may combine with the apoprotein after the latter is completely synthesized and released from the polysomes.
TWO RAPIDLY LABELED RNA SPECIES IN THE POLYSOMES OF ANTIBODY-PRODUCING LYMPHOID TISSUE
Authors: Kuechler Ernst , Rich Alexander
Published: May 2006

Popliteal lymph nodes of rabbits stimulated to produce antibodies were pulse labeled
in vivo
by direct injection of
3
H-uridine. RNA was then extracted from isolated polysomes and single ribosomes. Fractionation of this RNA by polyacrylamide gel electrophoresis revealed the synthesis of two discrete peaks of labeled RNA migrating in the region between 18S ribosomal and 4S transfer RNA. These peaks were found in the RNA extracted from polysomes but were absent from single ribosomes. When the polysomes were disrupted by EDTA treatment the RNA species no longer appeared as rapidly sedimenting material. These two RNA's have molecular weights near 2.2 × 10
5
and 3.7 × 10
5
daltons. The chemical and biological properties of these species as well as the molecular weights are consistent with those expected for monocistronic messenger RNA coding for the antibody L and H chains, respectively.
EFFECT OF PRESSURE ON THE APPARENT SPECIFIC VOLUME OF PROTEINS
Authors: Fahey Paul F. , Kupke D. W. , Beams J. W.
Published: May 2006

The magnetic densimeter has been employed to measure the densities and apparent specific volumes of certain proteins in aqueous solutions as a function of pressure. The method gave values in satisfactory agreement with those found in the literature for aqueous electrolyte solutions. A change in apparent specific volume of the monomeric proteins, ribonuclease and turnip yellow mosaic virus and its capsid protein, at pressures up to 400 atmospheres at 20°C was not observed within the precision of the measurements. Also, no change in the apparent specific volume of tobacco mosaic virus protein was observed as a function of these pressures whether the protein was predominantly in the polymerized or unpolymerized state. The magnetic densimeter was found to be a convenient instrument for measuring compressibilities of very small samples of solutions.
GEOMETRIC PROGRAMMING, CHEMICAL EQUILIBRIUM, AND THE ANTI-ENTROPY FUNCTION
Authors: Duffin R. J. , Zener C.
Published: May 2006

The culmination of this paper is the following duality principle of thermodynamics: maximum
S
= minimum
S
*
. (1) The left side of relation (1) is the classical characterization of equilibrium. It says to maximize the entropy function
S
with respect to extensive variables which are subject to certain constraints. The right side of (1) is a new characterization of equilibrium and concerns minimization of an anti-entropy function
S
*
with respect to intensive variables. Relation (1) is applied to the chemical equilibrium of a mixture of gases at constant temperature and volume. Then (1) specializes to minimum
F
= maximum
F
*
, (2) where
F
is the Helmholtz function for free energy and
F
*
is an anti-Helmholtz function. The right-side of (2) is an unconstrained maximization problem and gives a simplified practical procedure for calculating equilibrium concentrations. We also give a direct proof of (2) by the duality theorem of geometric programming. The duality theorem of geometric programming states that minimum cost = maximum anti-cost. (30)
REGULATION OF SUGAR TRANSPORT IN ISOLATED BACTERIAL MEMBRANE PREPARATIONS FROM
Escherichia coli
Authors: Kaback H. R.
Published: May 2006

The experiments presented in this paper demonstrate that glucose transport via the phosphoenolpyruvate-phosphotransferase system as studied in isolated
E. coli
membrane preparations is subject to regulation by sugar-P's. Glucose transport in these preparations is inhibited by glucose-6-P, glucose-1-P, and, to a lesser extent, by other P-esters. There appear to be two inhibitory sites, one specific for glucose-1-P and related sugar-1-P's and the other specific for glucose-6-P and related sugar-6-P's. The inhibition by these sugar-P's is noncompetitive, and the inhibitory sites are separate, subject to independent control, and apparently are accessible from outside the membrane. Furthermore, glucose-6-P is able to reverse partially inhibition of glucose transport by glucose-1-P and vice versa. Preliminary evidence is presented indicating that glucose-1-P may play a central role in the regulation of sugar transport in general, by virtue of its ability to inhibit selectively the transport of sugars other than glucose.
GENETIC CONTROL BY THE
hr
-LOCUS OF SUSCEPTIBILITY AND RESISTANCE TO LEUKEMIA
Authors: Meier H. , Myers D. D. , Huebner R. J.
Published: May 2006

Leukemia was observed in 45 per cent of hairless mice at 8 to 10 months of age and 72 per cent at 18 months. The incidence of leukemia in normal heterozygous mice of the same age is about one per cent at 10 months and increases to 20 per cent at 18 months. Other tumors are rare; two mammary adenocarcinomas occurred in heterozygotes, and an epidermal squamous cell carcinoma was found in a hairless mouse. Murine leukemia virus was isolated from normal and leukemic mice of both genotypes on SWR/J- and C57L/J-METC, but not BALB/cJ-METC. If this virus is responsible for the leukemia in HRS/J mice, the mutant gene (
hr
) enhances susceptibility and the wild-type allele (+) induces resistance to leukemogenesis, i.e., malignant transformation of reticulo-endothelial tissues occurs rather than inhibition of viral replication as both genotypes harbor virus in high titers. The two types of HRS/J mice,
hr/hr
and
hr
/+, are congenic, i.e., they differ only with respect to one allele (
hr
or +) at the mutant locus. This single gene difference should lend itself to analysis of the interaction of a specific gene and murine leukemia virus.
FUNCTIONAL INTERDEPENDENCE OF RIBOSOMAL COMPONENTS OF
Escherichia coli
Authors: Apirion David , Schlessinger David
Published: May 2006

Ribosomes are made up of parts that interact so strongly that a mutation in one of them can mask the effect of mutation in another. For example, when a mutation to neomycin resistance, which is a ribosome mutation, is introduced into cells carrying a ribosome mutation to spectinomycin resistance, some of the doubly mutant strains were phenotypically sensitive to spectinomycin, even though the mutation to spectinomycin resistance is still intact and recoverable in appropriate crosses. The neomycin mutant alleles that cause masking were shown by genetic tests to be in an identified locus that affects ribosomes. Protein synthesis in cell-free extracts of a double mutant strain was as sensitive to the action of spectinomycin as was the extract of the doubly sensitive parental strain. Thus, the masking effect of neomycin mutations on the spectinomycin mutation is exerted at the level of the ribosomes.

We conclude that the genetic analysis of an organelle like the ribosome is likely to be severely complicated by pleiotropic effects and by interactions among its component parts and that the ribosomal binding sites for spectinomycin and neomycin are partially interdependent. These results suggest that the function of the ribosome requires a very precise conformation of all its elements, some of which are interdependent. Modification in one element can thus alter the function of another or even render the entire structure nonfunctional.
POLYPEPTIDE CHAIN INITIATION IN
E. coli
: STUDIES ON THE FUNCTION OF INITIATION FACTOR F
1
Authors: Chae Yung-Bog , Mazumder Rajarshi , Ochoa Severo
Published: May 2006

The requirement of initiation factors F
1
(highly purified) and F
2
(electrophoretically homogeneous) for ribosomal binding of N-formylmethionyl transfer RNA (fMet ∼ tRNA) at low Mg
2+
concentration (3.5 mM), with the trinucleoside diphosphate ApUpG as messenger, was studied under various experimental conditions with 30
S
+ 50
S
ribosomes and with 30
S
subunits alone. The results were qualitatively the same in both cases but the amount of binding was two to three times higher when both 30
S
and 50
S
subunits were present.

Although there was a virtually absolute requirement for F
2
in all cases, considerable binding occurred at 0° in the absence of added F
1
. F
1
addition stimulated binding up to twofold under these conditions. However, at 25°, the temperature at which the reaction is usually carried out, there was very little binding with F
2
alone and addition of F
1
stimulated the reaction five- to sixfold.

Contrary to current belief, the GTP analog 5′-guanylyldiphosphonate (GMP-PCP) cannot replace GTP in the binding reaction. In particular, there was but little stimulation of binding (about 1.5-fold) by addition of F
1
to F
2
-containing samples when GMP-PCP was used. In marked contrast, binding was stimulated up to sevenfold by addition of F
1
when GTP was substituted for the analog. Under these conditions, there was an ApUpG and F
1
-dependent hydrolysis of GTP. This is observable with 30
S
subunits alone and can hardly be related to the occurrence of translocation.

The results may be interpreted to mean that a complex relatively stable at 0°, but less stable at 25°, is formed upon addition of F
2
alone. Conversion of the less stable to the more stable form of complex is made possible by addition of F
1
. This is accompanied or mediated by cleavage of GTP.
CONTROL OF SPECIFIC GENE EXPRESSION EXAMINED IN SYNCHRONIZED MAMMALIAN CELLS
Authors: Martin David W. , Tomkins Gordon M. , Bresler Michael A.
Published: May 2006

The control of synthesis of the steroid-inducible enzyme, tyrosine aminotransferase (TAT), has been studied in synchronized cultures of HTC cells, an established line of rat hepatoma cells. During the mitotic and early G1 periods of the generation cycle of cells previously exposed to inducer, TAT synthesis is maximal in the absence of inducer, i.e., synthesis is constitutive. (By contrast, in random cells maximal TAT synthesis is always dependent upon the presence of the inducer.) After the third hour of G1 “G1[3]”), TAT synthesis is inhibited by a specific posttranscriptional repressor, the formation of which requires RNA synthesis. We speculate that this repressor is antagonized by the steroid inducer.

The degradation of TAT during mitosis and G1 is constant and not affected by cycloheximide or actinomycin D in our experiments.
DELINEATION OF CYSTINE AND CYSTEINE TRANSPORT SYSTEMS IN RAT KIDNEY CORTEX BY DEVELOPMENTAL PATTERNS
Authors: Segal Stanton , Smith Inez
Published: May 2006

The impaired ability of neonatal rat kidney cortex slices to take up L-cystine at a time when the ability to accumulate cysteine is similar to that of adult tissues indicates the separate nature of the transport processes for these amino acids. Dissimilarities in dependence on oxygen and temperature are also indicative of different transport systems. The intracellular form of the amino acid was largely cysteine when either cystine or cysteine was the transported substrate although significant amounts of both were incorporated into reduced glutathione. No difference in intracellular forms was found between neonatal and adult tissue.
ON THE CONFORMATIONS OF HALLUCINOGENIC MOLECULES AND THEIR CORRELATION
Authors: Chothia Cyrus , Pauling Peter
Published: May 2006

There are only a few possible conformations of D-lysergic acid diethylamide and hallucinogenic derivatives of tryptamine and phenylethylamine. Of these possible conformations there is a high structural correlation among the probable conformations of active hallucinogenic molecules and between these conformations and the known conformations of several central nervous system transmitter molecules.
THE PATHOGENESIS OF AUTOIMMUNITY IN NEW ZEALAND MICE, I. INDUCTION OF ANTINUCLEIC ACID ANTIBODIES BY POLYINOSINIC·POLYCYTIDYLIC ACID
Authors: Steinberg Alfred D. , Baron Samuel , Talal Norman
Published: May 2006

Antibodies to DNA and RNA were induced in young NZB/NZW F
1
(B/W) female mice following multiple injections of the interferon-inducer polyinosinic·polycytidylic acid (poly I·poly C). Despite serum concentrations of interferon adequate to inhibit the C-type murine leukemia viruses, there was an acceleration of the autoimmune disease in these animals. Anti-RNA, but not anti-DNA antibodies, were induced in B/W male mice, as well as in NZB and NZW mice. Anti-RNA antibodies were also found in 50 per cent of female B/W mice who had never received poly I·poly C and in 8 of 24 sera from patients with systemic lupus erythematosus.

These results suggest that double-stranded RNA functions as a potent antigen in New Zealand mice. Naturally occurring nucleic acids (e.g., viruses) probably act as stimuli to a genetically hyperreactive immune system. According to this hypothesis, the unusual feature in this disease is not a unique virus, but rather the unique genetic susceptibility of the B/W (particularly female) host to immunization with nucleic acids. A similar pathogenetic mechanism may be operative in some humans with systemic lupus erythematosus.