bluuebunny/crossref_metadata_2025 huggingface dataset:
ENZYMATIC INACTIVATION OF PEPTIDE HORMONES POSSESSING A C-TERMINAL AMIDE GROUP
Authors: Glass John D. , Schwartz I. L. , Walter Roderich
Published: May 2006

A partially purified enzyme extracted from the bladder of the toad,
Bufo marinus
L., was found to cleave the glycine amide moiety from oxytocin, 8-lysine-vasopressin, 8-arginine-vasopressin, and other hormone analogs terminating in a primary carboxamide group; however, this enzyme does not attack hormone analogs terminating with a methylamide, dimethylamide, or carboxyl group. Preliminary experiments indicate that a functionally similar enzyme is also present in the mammalian kidney, the major target organ of neurohypophyseal antidiuretic hormones. This enzyme, besides inactivating oxytocin and 8-lysine-vasopressin, also cleaves the phenylalanine amide moiety from a tetrapeptide analog of gastrin, another hormone terminating in a primary carboxamide group. Attention is drawn to the possible general significance of “carboxamidopeptidases” for the termination of the action of peptide hormones in which the C-terminal amino acid residue bears a carboxamide group.
EQUILIBRIUM MEASUREMENTS OF EMBRYONIC CHICK CELL ADHESIVENESS, I. SHAPE EQUILIBRIUM IN CENTRIFUGAL FIELDS
Authors: Phillips Herbert M. , Steinberg Malcolm S.
Published: May 2006

Sorting-out and other morphogenetic rearrangements of embryonic cells have been attributed to the spontaneous movements of mutually adhesive cells toward configurations of minimal adhesive free energy. Testing this hypothesis requires measuring those particular adhesive properties that would determine such equilibrium configurations.

We have devised a modification of the sessile drop method for making the required measurements.

This communication is a preliminary report of experiments demonstrating that intercellular adhesiveness is reflected in the equilibrium shapes of centrifuged cell aggregates.
PURIFICATION OF AN ESTROPHILIC PROTEIN FROM CALF UTERUS
Authors: Sombre E. R. De , Puca G. A. , Jensen E. V.
Published: May 2006

A method has been devised for purifying the estrogen-binding protein (“uptake receptor”) of uterine cytosol which circumvents the marked tendency of this receptor to aggregate during attempted isolation. Ammonium sulfate precipitation of the estradiol-receptor complex of calf uterine cytosol in the presence of calcium ions yields both an 8
S
complex and its 4
S
subunit which are stable during further purification by gel filtration and ion exchange chromatography. The major product is the 4
S
complex which does not revert to 8
S
in the absence of salt and which has been purified about 2500-fold. The approximate isoelectric points of these partially purified 8
S
and 4
S
complexes are 5.8 and 6.4, respectively.
ORGANIC ANION-BINDING PROTEIN IN RAT LIVER: DRUG INDUCTION AND ITS PHYSIOLOGIC CONSEQUENCE
Authors: Reyes Humberto , Levi A. Jonathan , Gatmaitan Zenaida , Arias Irwin M.
Published: May 2006

The administration of phenobarbital to rats enhanced hepatic uptake of an organic anion, bromsulphalein,
in vivo
and simultaneously increased the amount of Y, a hepatic cytoplasmic organic anion-binding protein. This study supports the postulate that Y is a major determinant in the selective hepatic uptake of certain organic anions from plasma. Induction of Y may contribute to the enhanced hepatic uptake and metabolism of various organic anions (drugs, hormones, etc.) produced by phenobarbital and other agents.
A PROPOSED COMMON ALLOSTERIC MECHANISM FOR ACTIVE TRANSPORT, MUSCLE CONTRACTION, AND RIBOSOMAL TRANSLOCATION
Authors: Hill Terrell L.
Published: May 2006

It is suggested that active transport, muscle contraction, and ribosomal translocation may all make use of a common allosteric mechanism in which ATP or GTP serves as both the effector and substrate and in which a conformational change in a protein (enzyme) moves or exerts a force on a second ligand. The enzymatic splitting of ATP or GTP provides the driving force for the process and allows repetition of the steady-state cycle.
ON THE GEOMETRICAL ARRANGEMENT OF THE PROTEIN SUBUNITS OF HUMAN SERUM LOW-DENSITY LIPOPROTEIN: EVIDENCE FOR A DODECAHEDRAL MODEL
Authors: Pollard H. , Scanu A. M. , Taylor E. W.
Published: May 2006

Ultracentrifugal and electron microscopic studies of human serum low-density lipoprotein (LDL) and several of its derivatives led to the formulation of a model in which the 20 protein subunits, probably globular, are arranged in a dodecahedral pattern with icosahedral symmetry. In such a model the LDL surface is occupied by both protein and lipids, predominantly phospholipids, as supported by the results of the hydrolysis of LDL by phospholipase A and C. Neutral lipids (cholesterol esters and glycerides) would be in the interior of the molecule.
ON THE MECHANISM OF ACTION OF ALDOSTERONE
Authors: Goodman David B. P. , Allen James E. , Rasmussen Howard
Published: May 2006

Studies to elucidate the mode of action of aldosterone have been carried out in the amphibian urinary bladder. The following previously reported hypotheses were evaluated: (1) aldosterone stimulates sodium transport by increasing the amount of sodium available to the sodium pump; (2) aldosterone enhances energy production for the sodium pump; and (3) aldosterone-stimulated sodium transport is obligatorily coupled to aerobic metabolism. In the present experiments, aldosterone potentiated the effect of vasopressin on sodium transport in the absence of aerobic metabolism or oxidative phosphorylation. This effect was not due to enhanced energy supply. Thus both hypotheses 2 and 3 appear not to be valid. In addition, aldosterone-stimulated sodium transport exhibited increased sensitivity to the specific inhibitor, ouabain, and this inhibition was readily reversed by K
+
. These findings, as well as previously reported work, have led us to propose that aldosterone stimulates sodium transport by inducing a change either in the sodium pump itself, i.e., synthesis or activation, or in its environment in the serosal plasma membrane of the responsive cells.
THE MECHANISM OF MESSENGER RNA TRANSLOCATION THROUGH RIBOSOMES
Authors: Culp William , McKeehan Wallace , Hardesty Boyd
Published: May 2006

The two recognized enzymatic steps involved in the extension of peptides on ribosomes of the 80
S
type have been studied in a highly purified transfer system derived from rabbit reticulocytes. Data presented are interpreted to reflect three ribosomal binding sites through which transfer RNA is moved in two independent enzymatic reactions each of which requires guanosine 5′-triphosphate hydrolysis. The binding enzyme facilitates translocation between the entry and acceptor ribosomal sites. Transferase II is involved in translocation between the acceptor and donor ribosomal sites. A model is proposed to account for movement of transfer RNA and messenger RNA between the ribosomal sites.
INTERBASE VIBRATIONAL COUPLING IN G:C POLYNUCLEOTIDE HELICES
Authors: Howard F. B. , Frazier J. , Miles H. Todd
Published: May 2006

The carbonyl stretching vibrations of G and C residues undergo frequency changes when a helical complex is formed from nonordered G and C components. We have prepared a series of two-stranded G:C helices having chemical and isotopic (
18
O) substitutions which lead to variation of the observed vibrational frequencies. Infrared spectra of these helices clearly demonstrate that vibrational coupling occurs between the guanine and cytosine residues in the helix. As a result of this coupling through the hydrogen bonds, the two carbonyl bands undergo frequency shifts of equal magnitude and opposite sign, with mixing of G and C character in the observed interacted vibrations.
ONCOGENES OF RNA TUMOR VIRUSES AS DETERMINANTS OF CANCER
Authors: Huebner Robert J. , Todaro George J.
Published: May 2006

Evidence from sero-epidemiological studies and from cell culture studies supports the hypothesis that the cells of many, and perhaps all, vertebrates contain information for producing C-type RNA viruses. It is postulated that the viral information (the virogene), including that portion responsible for transforming a normal cell into a tumor cell (the oncogene), is most commonly transmitted from animal to progeny animal and from cell to progeny cell in a covert form. Carcinogens, irradiation, and the normal aging process all favor the partial or complete activation of these genes. An understanding of how normal cells and normal animals prevent expression of endogenous viral information would appear to offer one of the best hopes for the control of naturally occurring cancers.
A STIMULATION BY CYCLIC 3′,5′-ADENOSINE MONOPHOSPHATE OF AMINO ACID ACTIVATION AND POLYMERIZATION IN RETICULOCYTE HEMOLYSATES
Authors: Malkin Martin , Lipmann Fritz
Published: May 2006

With reticulocyte supernatant, cyclic 3′,5′-adenosine monophosphate at concentrations of 10
-3
to 10
-2
M
causes stimulation of aminoacyl-tRNA synthetases for some, e.g., valine and leucine, but not all, amino acids; it is highest at nonsaturating concentrations of ATP. Similar concentrations of cyclic 3′,5′-adenosine monophosphate are found to stimulate phenylalanine polymerization from phenylalanyl transfer ribonucleic acid on polyuridylic acid-charged reticulocyte ribosomes. The degree of stimulation is highest at low GTP concentrations. It is abolished by addition of phosphoenolpyruvate + pyruvate kinase, which stimulate similarly or more effectively at low GTP levels. Under the conditions of these experiments, cyclic 3′,5′-adenosine monophosphate did not appreciably inhibit GTP hydrolysis.
DEMONSTRATION OF DELAYED HYPERSENSITIVITY TO SOLUBLE ANTIGENS OF CHEMICALLY INDUCED TUMORS BY INHIBITION OF MACROPHAGE MIGRATION
Authors: Bloom Barry R. , Bennett Boyce , Oettgen Herbert F. , McLean Elisabeth P. , Old Lloyd J.
Published: May 2006

Sensitization to soluble antigens of chemically induced tumors is demonstrable in syngeneic strain 13 (inbred) guinea pigs by specific inhibition of macrophage migration. According to their capacity to (
a
) inhibit the migration of peritoneal cells from sensitized strain 13 donors or (
b
) release migration-inhibitory factor from their lymph node cells, the soluble antigens of three different chemically induced tumors did not cross react. This is in keeping with the absence of cross-reactivity among the same three tumors in previous tests of transplantation resistance or delayed hypersensitivity
in vivo
. Thus, inhibition of macrophage migration may provide a feasible assay
in vitro
for use in defining these soluble antigens further by physicochemical methods.
PROPERTIES OF A TEMPERATURE-SENSITIVE, RADIATION-SENSITIVE MUTANT OF
Escherichia coli
, II. DNA REPLICATION
Authors: Pauling Crellin , Hamm Lyla
Published: May 2006

We have described a temperature-sensitive, radiation-sensitive mutant of
Escherichia coli. In vitro
assays have demonstrated that DNA ligase activity is markedly reduced in this strain relative to that of the parent strain. Okazaki fragments of newly replicated DNA accumulate in this mutant strain upon growth at the restrictive temperature. These results imply that the same enzyme, DNA ligase, functions both in normal semiconservative replication and in nonconservative repair replication of DNA.
GENETICS OF SOMATIC MAMMALIAN CELLS, X. COMPLEMENTATION ANALYSIS OF GLYCINE-REQUIRING MUTANTS
Authors: Kao Fa-Ten , Chasin Lawrence , Puck Theodore T.
Published: May 2006

Complementation analysis at the single gene level has been carried out on 13 different, recessive, glycine-requiring mutants produced by action of mutagenic agents on the CHO-K1 Chinese hamster cell. The mutants form four different complementation classes indicating that at least four separate genes can produce a growth requirement for glycine. The four classes of mutants can be distinguished biochemically as well as genetically. Existence of these four mutant classes appears to explain the preponderance of the glycine-requiring forms in the auxotrophs produced by treatment of the parental cell with mutagenic agents.
A General Method for the Specific Staining of Intracellular Antigens with Ferritin-Antibody Conjugates
Authors: McLean J. D. , Singer S. J.
Published: May 2006

A general method is described whereby an intracellular macromolecule can be specifically stained with its antibody conjugated to ferritin. In this method cells or cell organelles are fixed, embedded in bovine serum albumin cross-linked with glutaraldehyde or formaldehyde, and then sectioned. This procedure preserves antigenic determinants as well as the cellular ultrastructure. The application of the ferritin-antibody conjugate to the section produces specific staining of the exposed antigen.
Entry of Organic Acid Anions into Roots
Authors: Jackson P. C. , Taylor J. M. , Hendricks S. B.
Published: May 2006

Entry of formate, acetate, succinate, and salts of several other organic acids into barley roots takes place chiefly as ions from solutions at pH 5 to 7. The results are in accord with entry of the organic acid predominantly at pH 5 as ions through hydrophylic regions of the limiting membranes rather than by distribution of the undissociated acid to lipid-rich regions, as has previously been held. These results with a plant tissue parallel observations of others indicative of similar hydrophylic properties of membranes from animals relative to transfer of ions and small nonelectrolytes.
Topological Relationship of Prophage λ to the Bacterial Chromosome in Lysogenic Cells
Authors: Freifelder David , Meselson Matthew
Published: May 2006

X irradiation converts bacterial sex factor DNA covalent circles to more slowly sedimenting forms according to first order kinetics. The rate of conversion is greater for sex factors carrying λ prophage than it is for nonlysogenized sex factors. The magnitude of the difference and the absence of covalent circular DNA from the product show that the prophage DNA is linearly inserted into the sex factor, as predicted by Campbell's model for lysogenization.
The Structural Gene for a T7 Endonuclease Essential for Phage DNA Synthesis
Authors: Center Melvin S. , Studier F. William , Richardson Charles C.
Published: May 2006

Infection of
Escherichia coli
with bacteriophage T7 results in the appearance of an endonuclease activity capable of hydrolyzing both double-and single-stranded DNA. Treatment with chloramphenicol prevents the induction of the endonuclease.
Amber
mutants of phage T7 defective in gene 3 are unable to produce the enzyme after infection of the nonpermissive host, and mutants that produce a heat-labile endonuclease were found, indicating that this gene is the structural gene for the enzyme. Gene 3 mutants synthesize only a limited amount of DNA. In addition, they are defective in carrying out the degradation of host DNA, suggesting that the gene 3 endonuclease is involved in this function.
Nitrogenaseless Mutants of
Azotobacter vinelandii
Authors: Sorger George J. , Trofimenkoff Diane
Published: May 2006

Mutants of Azotobacter which grow normally on excess ammonia under a variety of conditions and which grow slowly or not at all on atmospheric nitrogen have been isolated. Extracts of these strains have low or no detectable nitrogenase activity. There are three classes of mutants. Cell-free preparations of members of the first class possess an enhancement factor (EF+) which stimulates wild-type nitrogenase
in vitro
. Homogenates of members of the second class possess an enhanceable factor (EF-) which complements
in vitro
with extracts of the first class of mutants to give substantial nitrogenase activity. Preparations of members of the third class contain neither EF+ nor EF- activity. EF+ and EF- are repressed by the same conditions that repress nitrogenase. Molybdenum-deficient cells of the second class of mutants do not appear to contain EF- activity, but molybdenum deficient cells of the first class of mutants contain EF+. Because of these observations, EF+ is tentatively equated to azoferredoxin and EF- to molybdoferredoxin.
Trans-Species Rescue of Defective Genomes of Murine Sarcoma Virus from Hamster Tumor Cells with Helper Feline Leukemia Virus
Authors: Sarma Padman S. , Log T. , Huebner Robert J.
Published: May 2006

This report describes a trans-species rescue of defective MSV genome with helper leukemia virus derived from cats. This rescue was achieved by
in vitro
co-cultivation of hamster tumor cells with feline embryo cells in the presence of helper feline leukemia virus (FeLV), or by inoculation of tumor cells into FeLV-infected newborn cats.

The rescued focus-forming viruses produced foci in feline embryo cultures but not in cultures of mouse, rat, and hamster species. One isolate was tested and found to induce sarcoma in a kitten. Antigenic and viral interference studies indicated that the focus-forming virus has the viral envelope of FeLV. Virus stocks consisted of a mixture of focus-forming particles and a 1000-fold excess of helper FeLV. Virus assay pattern in feline embryo cultures with or without added helper FeLV indicated that this helper virus is required for the transformation of feline cells.
A Specific Complex between a Restriction Endonuclease and Its DNA Substrate
Authors: Yuan Robert , Meselson Matthew
Published: May 2006

In the presence of Mg
++
, ATP, and
S
-adenosylmethionine, the DNA restriction endonuclease R·K forms a specific complex with its DNA substrate. The complex can be detected by its retention on nitrocellulose membranes.
Photohydration of Uridine in the RNA of Coliphage R17, II. The Relationship between Ultraviolet Inactivation and Uridine Photohydration
Authors: Remsen J. F. , Miller N. , Cerutti P. A.
Published: May 2006

Uridine photohydrates (6-hydroxy-5,6-dihydrouridine) are the major products formed upon irradiation of the RNA bacteriophage R17 with ultraviolet light at 280 mμ, while cyclobutane-type pyrimidine dimerization does not occur to an appreciable extent. The suppression of dimerization may indicate that the RNA inside the phage is held in a rigid conformation in close contact with the phage protein. A value of 0.94 (±0.10) uridine photohydrates per biological hit is obtained from a correlation of the fraction of phage surviving with the number of photohydrates formed as a function of ultraviolet dose. It is concluded that uridine photohydrates represent a major part of the lethal damage caused by ultraviolet light in bacteriophage R17. An efficient system for dark repair of uridine photohydration seems to be lacking in
E. coli
.
Circadian Systems, V. The Driving Oscillation and the Temporal Sequence of Development
Authors: Pittendrigh Colin S. , Skopik Steven D.
Published: May 2006

A circadian oscillation (in the brain) of
Drosophila
spp. acts as a gating device restricting the emergence behavior of the adult to a limited fraction of each 24-hour cycle defined by that oscillator, but the oscillation does
not
gate intermediate steps of pupal development. Unlike the emergence act, such intermediate events in development occur at fixed times after prepupa formation and are totally independent of the phase of the ongoing oscillator that gates emergence behavior.
G (Gross) and H-2 Cell-Surface Antigens: Location on Gross Leukemia Cells by Electron Microscopy with Visually Labeled Antibody
Authors: Aoki Tadao , Boyse Edward A. , Old Lloyd J. , de Harven Etienne , Hämmerling Ulrich , Wood Harry A.
Published: May 2006

The hybrid-antibody method of locating cell-surface antigens in electron micrographs, with either ferritin or southern bean mosaic virus as the visual marker, was applied to the cells of a transplanted murine leukemia induced by Gross virus. The two antigens studied were (
a
) G (Gross) cell-surface antigen, which is a specific component of cells infected with Gross virus and is identified by cytotoxic hyperimmune C57BL/6 antiserum, and (
b
) H-2 antigen, which is the major histocompatibility determinant of the mouse.

Both antigens were represented on the cell surface in discrete circumscribed areas. Neither antigen was present on free Gross virions or on virions in the process of budding from the cell surface.

Thus G cell-surface antigen identified by C57BL mouse cytotoxic antiserum is not a constituent of the viral envelope, which accounts for the poor virus-neutralizing capacity of such antibody.

Virus maturation may take place preferentially at regions of the cell surface where H-2 and G antigens are absent, for budding was seldom seen in H-2
+
sectors and never convincingly in G
+
sectors.

In other experiments, serum from an untreated NZB mice aged 16 months gave labeling of the virion only, showing that this mouse strain, in contrast to C57BL and other strains, forms antibody to envelope antigen of Gross virus.
Hypoxanthine-Guanine Phosphoribosyltransferase Deficiency: Activity in Normal, Mutant, and Heterozygote-Cultured Human Skin Fibroblasts
Authors: Fujimoto Wilfred Y. , Seegmiller J. Edwin
Published: May 2006

Cultured skin fibroblasts from patients deficient for the enzyme hypoxanthine-guanine phosphoribosyltransferase (PRT) activity show very low but nevertheless significant levels of apparent PRT enzyme despite absence of detectable activity (<0.004% of normal) in erythrocytes of the same patients. In fibroblasts this mutant enzyme is more heat labile than the normal enzyme. These findings indicate that PRT deficiency in this disorder is not due to a deletion mutation of the PRT locus.

Individual cultured skin fibroblasts from heterozygote females for PRT deficiency show normal, intermediate, or very low levels of PRT activity. The mosaicism demonstrated in the heterozygotes for this X-linked disorder accounts for the cells with normal and very low activities of PRT. Intermediate activity can best be explained by the phenomenon of metabolic cooperation presumably from the transfer of either PRT enzyme or messenger RNA, from normal to mutant cells.
Stability of a Position-Effect Variegation in Normal and Transdetermined Larval Blastemas from
Drosophila melanogaster
Authors: Hadorn Ernst , Gsell Robert , Schultz Jack
Published: May 2006

Male genital disks of a yellow-variegated genotype were implanted into the abdomens of adult females to test the stability of variegated clones in the blastemas formed by the implants. Upon reimplantation into metamorphosing larval hosts, test fragments of the proliferating blastemas differentiated into variegated organs, with
yellow
and wild-type areas. In later transfer generations clones were separated, which appeared stable for either wild type or
yellow;
variegation was no longer occurring. In all the lines differentiation occurred also into other organs (allotypic) than those characteristically formed by the genital disc (transdetermination). The absence of new variegation in these transdetermined organs is discussed as evidence against a reversal to the embryonic state in the cells of the transdetermining blastema. The variegation process seems not to be affected by, nor does it in this case influence, the process of transdetermination.
Reversibility of the ATP:Glutamine Synthetase Adenylyltransferase Reaction
Authors: Mantel M. , Holzer H.
Published: May 2006

The reversibility of adenylylation of glutamine synthetase from
E. coli
by adenylyltransferase was demonstrated. Several positive effectors (Gln, 2-hydroxyethyl-
S
-cysteine, Trp and Met) stimulate the back reaction in the same manner as the forward reaction. The apparent Michaelis constant for PP
i
is 2.2 mM at pH 7.35. The pH optimum of the back reaction is 6.5-7 while the pH optimum of the forward reaction is 7.6. The apparent equilibrium constant in the presence of 10 mM Mg
2+
at pH 7.36 is 8.5 in favor of adenylylated glutamine synthetase and PP
i
. The equilibrium constant is strongly dependent from pH and from Mg
2+
concentration. There is a difference of about 0.5 to 1 kcal/mole free energy between the adenylyl-
O
-tyrosine bond and the pyrophosphate bond of adenosine triphosphate (ATP). It follows from these considerations that the adenylyl-
O
-tyrosine bond is an „energy-rich phosphate bond.”
Reaction Sites of Rotenone, Piericidin A, and Amytal in Relation to the Nonheme Iron Components of NADH Dehydrogenase
Authors: Gutman M. , Singer Thomas P. , Beinert Helmut , Casida John E.
Published: May 2006

The locus of inhibition of nicotinamide adenine dinucleotide, reduced form (NADH) oxidation in mitochondria by rotenone, piercidin A, and barbiturates is considered in the light of available information. Most lines of evidence indicate that the point of inhibition is on the O
2
side of NADH dehydrogenase. Kinetic experiments on the substrate-induced appearance of the electron paramagnetic resonance signal at
g
= 1.94 in membrane preparations (ETP) reveal that these inhibitors do not interfere with the reduction of the electron paramagnetic resonance detectable iron by NADH. Our spectrophotometric studies on complex I give no evidence for absorbance differences between untreated and rotenone or piericidin inhibited preparations, which can be attributed to nonheme iron. Whatever changes were observed appear to be due to cytochromes. These experiments, therefore, do not support the idea that in inhibited preparations electron transport is interrupted between the flavin and nonheme iron components of NADH dehydrogenase.

The specific binding of rotenone and piericidin seems to involve both lipid and protein. The possibility that NADH dehydrogenase participates in the binding is suggested by the apparent stoichiometric relation between specific binding site titer and NADH dehydrogenase content and the profound effect of mersalyl inhibition of the enzyme on piericidin binding capacity.

ETP, electron transport particle.
Template Properties of Complementary Fractions of Denatured Microbial Deoxyribonucleic Acids
Authors: Karkas John D. , Rudner Rivka , Chargaff Erwin
Published: May 2006

DNA preparations from seven bacterial species and from
E. coli
phage T4, and also the complementary L and H fractions into which these DNA specimens, after denaturation, were separated by chromatography on methylated albumin-kieselguhr columns, were studied as templates in the RNA polymerase system, and the nucleotide composition of the RNA products was determined. The RNA transcripts of the separated L and H fractions were found to be faithful copies of the respective DNA fractions. This suggests „transcription analysis” as a sensitive and reliable analytical technique for the determination of the base composition of denatured DNA. The L and H fractions of T4 DNA were shown, both by temperature-absorbance profiles and by transcription analysis, to be mutually complementary. The RNA products formed with intact DNA as the template were not exact copies of the latter; their composition indicated that under our experimental conditions the „heavy” DNA strand is transcribed preferentially.
Cooperative Effects in Models of Steady-State Transport across Membranes, I
Authors: Hill Terrell L. , Chen Yi-der
Published: May 2006

Three simple models are discussed which show cooperative effects in the steady-state transport of neutral molecules across a membrane. The Bragg-Williams approximation is employed, and its limitations discussed. In this approximation to cooperative problems, the diagram method for the calculation of steady-state probabilities and fluxes can still be used. This paper is closely related to one by Blumenthal, Changeux, and Lefever, and provides the foundation for sequels on an oscillatory steady-state phase-transition model (part II) and on simple models possibly related to steady-state potassium ion transport across a nerve membrane (part III).
The Reductive Inactivation of UDPgalactose-4-Epimerase from Yeast and
E. coli
Authors: Kalckar Herman M. , Bertland Alexander U. , Bugge Birgitte
Published: May 2006

The prosthetic groups of UDPgalactose-4-epimerase from yeast and
E. coli
can be reduced by incubation with D-galactose or L-arabinose provided that 5′ uridylic acid (5′UMP) is also present. This type of concerted reduction can also be performed using sodium borohydride. The latter type of reduction also depends on the addition of 5′UMP. Enzymatic analysis of the released prosthetic group by means of lactic dehydrogenase and pyruvate revealed that the pyridine nucleotide of the reduced epimerase generated in the concerted reaction is dehydrogenated in the 4-position of the pyridine ring.

The catalytic activity of the reduced epimerase is much lower than that of epimerase (10-15% of native epimerase). This reductive inactivation was also found in crude epimerase preparations from
E. coli
, again provided 5′UMP is present. Fractionated
E. coli
epimerase subjected to the concerted reduction show a striking fluorescent enhancement of the order of magnitude of that observed in the purified yeast epimerase. Unlike the latter, however,
E. coli
epimerase also becomes fluorescent upon addition of the specific substrate UDPgalactose.

The physiological aspects of the phenomenon as related to induction of the galactose genes is discussed.
Nicotinic Acid Metabolism, V. A Cobamide Coenzyme-Dependent Conversion of α-Methyleneglutaric Acid to Dimethylmaleic Acid
Authors: Kung H. F. , Cederbaum S. , Tsai L. , Stadtman T. C.
Published: May 2006

A new B
12
-coenzyme-dependent isomerization, catalyzed by extracts of a nicotinate-fermenting clostridium, results in the conversion of α-methyleneglutaric acid to dimethylmaleic acid. These two acids are intermediates in the multistep anaerobic process wherein nicotinate is converted, ultimately, to one mole each of propionate, acetate, carbon dioxide, and ammonia.

Dimethylmaleic acid reacts in its anhydride form with 2,4-dinitrophenylhydrazine to form
N
-2′,4′-dinitrophenyl-anilino-3,4-dimethylmaleimide. The characteristic reddish color exhibited by the latter derivative in alkaline solution serves as a convenient quantitative assay for dimethylmaleic acid. Comparison of the 2,4-dinitrophenylhydrazine derivatives of the product of the enzymic reaction and of synthetic dimethylmaleic anhydride showed them to be identical in every respect.
Singular Integrals and the Principal Series, II
Authors: Knapp A. W. , Stein E. M.
Published: May 2006

A further study is made of the intertwining operators for the representations of the simple Lie groups of real rank one. We extend and apply this to the higher rank case, obtaining various results dealing with reducibility of principal series and existence of complementary series.
Binding of Adenosine 3′:5′-Cyclic Phosphate to G Factor of
Escherichia coli
, and Its Effects on GTPase, RNase V, and Protein Synthesis
Authors: Kuwano Michihiko , Schlessinger David
Published: May 2006

Unique among adenine nucleotides tested by filter binding assays, 3′:5′-cyclic AMP binds to the G translocation factor. Binding is dependent on the presence of GTP, and is inhibited by GDP, by the analog 5′-β,γ-methylene GTP, and by the antibiotic fusidic acid. The cAMP seems to be released during the ribosome-dependent translocation of charged tRNA catalyzed by G factor. Bound cAMP inhibits GTPase and ribosome-associated degradation of messenger RNA, but does not inhibit protein synthesis. cAMP might thereby regulate the ratio of productive to degradative transits of ribosomes on messenger RNA, and this may account for some part of its profound effect on levels of specific bacterial messenger RNA species.
Further Studies on Loss of T-Antigen from Somatic Hybrids between Mouse Cells and SV40-Transformed Human Cells
Authors: Weiss Mary C.
Published: May 2006

The study of hybrids from three crosses between mouse cells and SV40-transformed human cells have established a positive correlation between the loss of human chromosomes and that of the SV40-induced T-antigen from the hybrid cells. These results, as well as those of other workers, provide strong support for the hypothesis of the integration of the SV40 genome in the chromosomes of transformed cells. Further, it has been shown that hybrid cells which have lost T-antigen are capable of synthesizing this antigen upon infection with SV40, thereby demonstrating that loss of the viral antigen from the hybrid cells is not due to loss of some cellular gene required for the expression of the viral genome. Results of karyological analyses of the hybrid cells argue against the existence of a single specific integration site for the SV40 genome in human cells.
A Cell-Associated Factor Essential for Formation of an Infectious Form of Rous Sarcoma Virus
Authors: Hanafusa H. , Miyamoto T. , Hanafusa T.
Published: May 2006

Formation of a specific type of infectious Rous sarcoma virus called RSV(0) has been found to occur only in a certain type of chick embryo cell in the absence of avian leukosis virus. Although these chick cells lack any complete form of avian leukovirus, they appear to carry a genetic factor essential for formation of infectious RSV(0). A factor-deficient cell can be converted to a producer of infectious RSV(0) by infection with Rous sarcoma virus or avian leukosis virus which has been grown in factor-containing cells. Evidence is presented to show that the factor determines both the antigenic and host range specificity of RSV(0).
Membrane Structure: Lipid-Protein Interactions in Microsomal Membranes
Authors: Trump Benjamin F. , Duttera Sue M. , Byrne William L. , Arstila Antti U.
Published: May 2006

The relationships of phospholipid to membrane structure and function were examined in hepatic microsomes. Findings indicate that normal microsomal membrane structure is dependent on lipid-protein interactions and that it correlates closely with glucose-6-phosphatase activity. Modification of most phospholipid with phospholipase-C is associated with widening of the membrane which can be reversed following readdition of phospholipid.
Structure and Function of
E. coli
Formylmethionyl tRNA, I. Effect of Modification of Pyrimidine Residues on Aminoacyl Synthetase Recognition
Authors: Schulman LaDonne H.
Published: May 2006

E. coli
formylmethionyl tRNA (tRNA
fMet
) has been irradiated with ultraviolet light in the presence of Mg
2+
to the extent of 50 per cent inactivation of amino acid acceptance. Separation of active and inactive molecules after irradiation has shown that ultraviolet light modification of the uridine in the anticodon, the uridine in the small loop, the 4-thiouridine, and the pyrimidines in the double-stranded stem adjacent to the dihydrouridine loop has no effect on aminoacylation or transformylation. The ultraviolet light-induced inactivation of methionine acceptance by tRNA
fMet
is due almost entirely to modification of the cytidine residues in the 3′-terminal CCA—OH sequence.
Formation of a Vaccinia Virus Structural Polypeptide from a Higher Molecular Weight Precursor: Inhibition by Rifampicin
Authors: Katz Ehud , Moss Bernard
Published: May 2006

A vaccinia virus core polypeptide, with a molecular weight of 76,000 and a relative deficiency in tryptophan, was shown by pulse-chase experiments to form from a precursor. The latter may be a rapidly labeled, 125,000-molecular weight, tryptophan-deficient, virus-induced polypeptide, which diminished in quantity during the chase period and was barely detectable after two to three hours.

Rifampicin completely prevented the formation of the core polypeptide without inhibiting the synthesis of the precursor. A rifampicin-resistant vaccinia mutant was used to demonstrate the specificity of this effect. The sequence of events after the removal of the drug suggested that cleavage of the precursor occurs during the formation of the virus core. Rifampicin appears to act by interrupting earlier maturational events which precede the formation of the core polypeptide.
Synthesis of Proteins in Cells Infected with Herpesvirus, VI. Characterization of the Proteins of the Viral Membrane
Authors: Kaplan Albert S. , Ben-Porat Tamar
Published: May 2006

The envelope of pseudorabies virions can be removed by treatment with Triton X-100, leaving the nucleocapsid intact. The viral envelope removed in this fashion contains all the glycoproteins and about 40 per cent of the proteins of the virions. Analysis by polyacrylamide gel electrophoresis revealed that the envelope proteins migrate as four distinct peaks, all of which contain glycoproteins. The proteins of the nucleocapsids migrate in the gels as six distinct peaks.
Directional Character of Proton Transfer in Enzyme Catalysis
Authors: Wang Jui H.
Published: May 2006

Hydrogen bonding can facilitate proton transfer in certain directions and retard proton transfer in certain other directions. By assuming that directed proton transfer along strategically oriented hydrogen bonds in the enzyme-substrate complex plays an important role in determining the efficiency and specificity of the enzyme, we present a unified interpretation for the reported observations on carbonic anhydrase and α-chymotrypsin.
Properties of RNA Transcriptase in Reovirus Subviral Particles
Authors: Levin Daniel H. , Mendelsohn Naomi , Schonberg Michael , Klett Hanna , Silverstein Samuel , Kapuler Alan M. , Acs George
Published: May 2006

Subviral particles containing reovirus RNA transcriptase have been isolated from extracts of virus-infected mouse fibroblast cells. The purified particles which lacked the outer protein capsomeres of the mature virion had a buoyant density of 1.43-1.44 g/ml in CsCl and contained all of the double-stranded RNA genome of the intact virus. The particles were free of nuclease activity. RNA synthesis required all four ribonucleoside triphosphates and was dependent on magnesium or manganese; optimal activity required potassium or ammonium ions. In the presence of a ribonucleoside triphosphate regenerating system, reaction rates were linear for 20 hr. RNA yields of 40-fold in excess of input template could be obtained. Completed RNA chains were released from the subviral particles. In the course of RNA synthesis, the double-stranded RNA template was fully conserved. The RNA products formed
in vitro
displayed profiles in sucrose gradients similar to those found for
in vitro
reovirus mRNA. The RNA products were single-stranded and did not self-anneal. Over 90 percent of the transcriptase products could be annealed with template double-stranded RNA. The annealed products migrated in acrylamide gels as double-stranded RNA, indicating efficient
in vitro
transcription.
CELLS INVOLVED IN CELL-MEDIATED AND TRANSPLANTATION IMMUNITY, II. A CONSIDERATION OF THE FUNCTIONAL IDENTITY OF THE CELLS INVOLVED IN BOTH HUMORAL AND CELL-MEDIATED IMMUNITY: A PHYLOGENETIC APPROACH
Authors: Richter Maxwell
Published: May 2006

The literature concerned with the types of cells that participate in the humoral and cell-mediated immune response has been reviewed. It is postulated that the initial cells that are involved in mediating both types of immunity are functionally identical in that both are antigen-reactive cells. In the case of the humoral immune response, the interaction of the antigen-reactive cells with the antigen leads to the release or transfer of “information” to the antibody-forming cell, resulting in the synthesis and secretion of antibody molecules. In the case of cell-mediated immunity, it is considered that the primitive antigen-reactive cell itself transforms into the sensitized cell which infiltrates the site of antigen administration.
β-GALACTOSIDE TRANSPORT IN BACTERIAL MEMBRANE PREPARATIONS: ENERGY COUPLING VIA MEMBRANE-BOUND D-LACTIC DEHYDROGENASE
Authors: Barnes Eugene M. , Kaback H. R.
Published: May 2006

The transport of β-galactosides by isolated membrane preparations from
Escherichia coli
strains containing a functional
y
gene is markedly stimulated by the conversion of D-lactate to pyruvate. The addition of D-lactate to these membrane preparations produces a 19-fold increase in the initial rate of uptake and a 10-fold stimulation of the steady-state level of intramembranal lactose or thiomethylgalactoside. Succinate, DL-α-hydroxybutyrate, and L-lactate partially replace D-lactate, but are much less effective; ATP and P-enolpyruvate, in addition to a number of other metabolites and cofactors, do not stimulate lactose transport by the vesicles. Lactose uptake by the membrane preparations in the presence of D-lactate requires oxygen, and is blocked by electron transport inhibitors and proton conductors; however, uptake is not significantly inhibited by high concentrations of arsenate or oligomycin. Furthermore, the P-enolpyruvate-P-transferase system is not involved in β-galactoside transport by the
E. coli
membrane vesicles. The findings indicate that the β-galactoside uptake system is coupled to the membrane-bound D-lactic dehydrogenase via an electron transport chain but does not involve oxidative phosphorylation.
Correlation of Isotope Effects with Molecular Forces, I. The Diatomic Molecule
Authors: Bigeleisen Jacob , Ishida Takanobu , Spindel William
Published: May 2006

The convergence properties of the individual terms in the finite orthogonal polynomial expansion of the partition function of a harmonic oscillator are examined as a function of the energy of the oscillator and the temperature of the system (
u
= ε/
kT
). The convergence of each term depends on the number of terms in the polynomial and the variable
u
. The
j
th term approaches within 1% of its asymptotic value when the order of the polynomial,
n
, equals (
u
/π) +
j
+ 1.

These favorable convergence properties of the finite polynomials are used to relate the partition function of an oscillator and the difference in chemical properties of isotopes directly to molecular and intermolecular forces. A detailed discussion is given for the diatomic molecule. In this case it is possible to treat the quantum corrections of any order in terms of a single particle function multiplied by kinetic energy-coupling factors. The latter are formulated as simple mass ratios of the order of unity.
Enzyme Variability in the
Drosophila willistoni
Group, I. Genetic Differentiation Among Sibling Species
Authors: Ayala Francisco J. , Mourão Celso A. , Pérez-Salas Santiago , Richmond Rollin , Dobzhansky Theodosius
Published: May 2006

We have studied by gel electrophoresis the variability of 14 structural genes in four sibling species,
Drosophila willistoni, D. paulistorum, D. equinoxialis
, and
D. tropicalis
. Samples of about 30 populations from different parts of the distribution areas of each species were examined. Genetic variants are found at every locus; 67% of the loci are polymorphic, having two or more alleles, the rarer of which has a frequency of 5% or higher.

The gene frequencies are fairly uniform over the distribution area of each species, but considerably different in different species. It is estimated that individuals which belong to the different species differ on the average in somewhat more than one half of their gene loci. The morphological similarity of the four sibling species contrasts with the extensive diversity in their genetic materials.
Biological Membrane Structure, II. A Detailed Model for the Retinal Rod Outer Segment Membrane
Authors: Vanderkooi G. , Sundaralingam M.
Published: May 2006

A model, based on the available chemical, electron microscopic, and x-ray diffraction data, has been developed for the structure of the retinal rod outer segment membranes. The model consists of a double layer of globular protein molecules, with lipid bilayer filling the spaces between the proteins. The electron density across the membrane has been calculated and shown to be in agreement with that found by x-ray diffraction. The protein molecules „float” half submerged in a lipid field; this serves to orient them in the same way at all times relative to incident radiation in the intact retina.
An Approach to Conformational Analysis of Peptides and Proteins in Solution Based on a Combination of Nuclear Magnetic Resonance Spectroscopy and Conformational Energy Calculations
Authors: Gibbons W. A. , Némethy George , Stern Arnold , Craig Lyman C.
Published: May 2006

Simple criteria, based on the combined use of nmr spectral parameters and potential energy maps, are proposed for the conformational analysis of polypeptides and proteins. Experimentally determined coupling constants
3
J
NC
for the N-C
α
bond are consistent with the Karplus-Bystrov relationship. It is proposed therefore that
3
J
NC
can be used to distinguish (
a
) between right-and left-handed α-helices, (
b
) between α-helical, β-pleated sheet, and randomly coiled forms of peptides. The average
3
J
NC
for the random coil is predicted. The criteria proposed are valid for both L- and D-amino acids. Correlation between the Karplus-Bystrov relationship for
3
J
NC
and the peptide conformational potential energy map limits the possible values of the N-C
α
dihedral angle ϕ of each amino acid residue in a polypeptide and protein, and therefore presents a method of conformational analysis in solution superior to the use of either nmr or conformational maps alone. Nmr studies of hydrogen bonding or neighboring-group diamagnetic anisotropy reduce the number of possibilities consistent with the above criteria. A suggestion for evaluating the dihedral angle is presented. These criteria are useful provided the coupling constant is not obscured by line broadening.
Extraretinal Light Perception in the Sparrow, III: The Eyes Do Not Participate in Photoperiodic Photoreception
Authors: Menaker Michael , Roberts Richard , Elliott Jeffrey , Underwood Herbert
Published: May 2006

Photoperiodic control of testis growth in
Passer domesticus
(house sparrow) is mediated entirely by extraretinal photoreceptors in the brain. The eyes do not participate in photoperiodically significant photoreception. Removal of the pineal organ does not affect either the response to light or, to a first approximation, the process of recrudescence. The intensity of light reaching the retina and that reaching the extraretinal photoreceptor were varied independently. This technique will make it possible to study brain photoreception in species of birds that will not tolerate blinding. Extreme caution is necessary in the interpretation of brain lesion experiments in which reproductive function is modified, since photoreception by brain receptors of unknown anatomical location affects testicular state.
Polynucleotide Ligase-Catalyzed Joining of Deoxyribo-oligonucleotides on Ribopolynucleotide Templates and of Ribo-oligonucleotides on Deoxyribopolynucleotide Templates
Authors: Kleppe K. , van de Sande J. H. , Khorana H. G.
Published: May 2006

T4 polynucleotide ligase efficiently catalyzes the head-to-tail joining of the ribo-oligoadenylates, r-(pA)
8
and r-(pA)
10
, in the presence of high molecular weight deoxypolythymidylate. The enzyme also catalyzes the joining of deoxy-oligothymidylates, e.g., d-(pT)
10
, in the presence of ribopolyadenylate. The enzyme failed to bring about the joining of r-(pA)
10
when poly r-U was used as the template, although a slow formation of the expected activated intermediate from r-(pA)
10
was detected.
Electron-Nuclear Double Resonance of a Protein That Contains Copper: Evidence for Nitrogen Coordination to Cu(II) in Stellacyanin
Authors: Rist Günther H. , Hyde James S. , Vänngård Tore
Published: May 2006

Electron-nuclear double resonance has been used to study ligand hyperfine interactions of the copper (II) complex in a frozen solution of the blue protein stellacyanin. It is shown that the copper ion coordinates with at least one nitrogen ligand, and probably more than one, and that the copper ion is in a hydrophobic environment.
Amino Acid Sequence Similarities in Two Human Anti Gamma Globulin Antibodies
Authors: Capra J. Donald , Kunkel Henry G.
Published: May 2006

Certain individuals with hypergammaglobulinemic purpura contain in their serum anti gamma globulins of restricted heterogeneity. These antibodies, characteristically of the γG type, were isolated from two unrelated individuals and their light polypeptide chains were subjected to amino acid sequence analysis. Although these anti gamma globulin antibodies conform to the basic VK
1
sequence, substitutions not previously encountered were found in five positions. The two antibodies were identical with each other up to residue 40 from the
N
-terminus of the light chains.