bluuebunny/crossref_metadata_2025 huggingface dataset:
A metabolic indicator of photoperiodic timing.
Authors: Hillman W S
Published: May 2006

Characteristics of CO2 output patterns of axenic cultures of Lemna perpusilla are being sought that would serve as biochemically definable indicators of the crucial photoperiodic events during inductive light/dark schedules, using cycles with skeleton main light periods and overall periodicities of 24 hr. As the length of the main light period is increased over the range 4-10 hr, the daily times of maximal output on nitrate or ammonium media shift about 2.5 hr; there is a precisely parallel shift in the time of maximal photoperiodic sensitivity of flowering to a night interruption. These times do not depend on either a "drawn" or a "dusk" signal alone, but are functions of both. The time of maximal daily CO2 output on aspartate medium reflects only the dawn signal, suggesting that the display of some component of CO2 flux coupled to the photoperiodic timing mechanism can be controlled by modifying nitrogen metabolism.
Analysis of subunit organization in chicken erythrocyte chromatin.
Authors: Shaw B R , Herman T M , Kovacic R T , Beaudreau G S , Van Holde K E
Published: May 2006

Micrococcal nuclease digestion of intact chicken erythrocyte nuclei is shown to result in the formation of core nucleoprotein particles containing about 140 base pairs of DNA. These core particles, which are almost entirely devoid of histones f1 and f2c, are derived from transient nucleoprotein particles containing an average of approximately 180 base pairs of DNA. Oligomers of these latter particles may be isolated after brief nuclease digestion. The time course of digestion of these oligomers demonstrates the existence of "spacer" regions of more accessible DNA between core particles. Redigestion of purified monomer core nucleoprotein particles gives rise to both single-strand and double-strand DNA fragment patterns similar to those resulting from digestions of chromatin in situ. This observation indicates that the core particles we isolate are representative of nucleoprotein structures existing within the nucleus.
Effect of Xenopus laevis oocyte extract on supercoiled simian virus 40 DNA: formation of complex DNA.
Authors: Gandini Attardi D , Martini G , Mattoccia E , Tocchini-Valentini G P
Published: May 2006

A soluble cell-free extract derived from stage 6 Xenopus laevis oocytes is described. From supercoiled simian virus 40 DNA the extract produces nicked circles (having a single-strand scission), linear molecules of full unit size, shorter length fragments, and various forms of complex DNA.
Association of cell surface receptors for melanotropin with the Golgi region in mouse melanoma cells.
Authors: Varga J M , Moellmann G , Fritsch P , Godawska E , Lerner A B
Published: May 2006

Binding of beta-melanotropin (betal-melanocyte stimulating hormone) to mouse melanoma cells occurs in a region on the cell surface overlying the Golgi complex. This association was demonstrated by labeling cells with fluorescein isothiocyanate hormone and by locating the Golgi complex with a histochemical test for thiamine pyrophosphatase activity. The biologically active fluorescent hormone appears on the surface and later in vesicles in the malanized cells, as judged by fluorescence microscopy. It is conceivable that internalization of the hormone is instrumental in the process of hormonally induced melanization. Because initial and late events of hormonally induced pigmentation are related to the Golgi complex, it is likely that instructions that follow the attachment of melanotropin to receptors are carried out in a compartmentalized manner.
Regulation by steroid hormones of phosphorylation of specific protein common to several target organs.
Authors: Liu A Y , Greengard P
Published: May 2006

The effect of in vivo administration of steroid hormones on the endogenous phosphorylation of individual proteins in cell sap from several target tissues has been studied using the technique of discontinuous sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The hormones studied (and their respective target organs) were: 17 beta-estradiol [1,3,5(10)-estratriene-3, 17beta-diol] (uterus); testosterone (17 beta-hydroxy-4-androsten-3-one) (ventral prostate and seminal vesicle)' cortisol (11beta, 17alpha, 21-trihydroxy-4-pregnene-3,20-dione) (liver); aldosterone (the 18.11-hemiacetal of 11beta,21-dihydroxy-3,20-dioxo-4-pregnen-18-al) (toad bladder). In each of the five target organs studied, pretreatment with the appropriate hormone reduced the amount of 32P incorporated from [gamma-32P]ATP into an apparently common protein band present in the cytosol fraction. The endogenous phosphorylation and dephosphorylation of this protein was also regulated by cAMP. This protein, designated SCARP (steroid and cyclic adenosine 3':5' monophosphate regulated phosphoprotein), was estimated to have an apparent molecular phoprotein), was estimated to have an apparent molecular weight of 54,000 in the gel electrophoresis system used. The effect of the steroid hormones in decreasing the phosphorylation of SCARP was specific for their respective target tissues. The effect of 17beta-estradiol and of testosterone on SCARP could be observed as early as two hours after a single dose of the steroid. A protein synthesis inhibitor, cycloheximide, abolished the effect of the steroid hormones, but not that of cAMP, on the endogenous phosphorylation of SCARP. The results suggest that steroid hormones regulate either the amount of SCARP or its ability to become phosphorylated. This regulation of a single species of protein by several types of steroid hormones in different target organs raises the possibility that this common biochemical action may be a component of the mechanism by which these steroids achieve some of their biological effects.
Nuclear magnetic resonance studies of the helix-coil transition of poly (dA-dT) in aqueous solution.
Authors: Patel D J , Canuel L
Published: May 2006

The well-resolved base and sugar proton resonances in the high resolution proton nuclear magnetic resonance (NMR) spectra of poly(dA-dT) can be monitored during the helix-coil transition. The observable resonances shift upfield on helix formation and the temperature-dependent chemical shifts exhibit a melting temperature t 1/2 = 69.9 +/- 0.3 degrees for 18.8 mM (with respect to phosphorus) poly(dA-dT) in 0.5 M Tris, 0.1 M cacodylate, D2O, pH 7.05. The observable protons are in fast exchange throughout the poly (dA-dT) helix-coil transition. The adenine H2 resonance that shifts upfield by about 1 ppm on helix formation exhibits uncertainty broadening in the fast exchange region...
Cloning of
Escherichia coli
DNA that controls cell division and capsular polysaccharide synthesis
Authors: Berg Patricia E. , Gayda Randall , Avni Hanna , Zehnbauer Barbara , Markovitz Alvin
Published: May 2006

A 2 × 10
6
dalton DNA fragment that controls cell division, capsular polysaccharide synthesis, and enzymes of capsular polysaccharide synthesis has been cloned.
Stringent factor from Escherichia coli directs ribosomal binding and release of uncharged tRNA.
Authors: Richter D
Published: May 2006

Uncharged tRNA is preferentially bound to the peptidyl site of the ribosome in the absence of stringent factor ,but in its presence is directed to the acceptor site. The synthesis of pppGpp and ppGpp is initiated by tRNA bound in the acceptor but not in the peptidyl site. In this reaction, tRNA is not permanently attached to the acceptor site. Uncharged [32P] tRNA but not 3H-labeled stringent factor is released from the ribosome after each round of stringent factor-dependent hydrolysis of ATP. ATP-32PPi-exchange experiments reveal that exchange is independent of the presence of GTP but strongly enhanced by the addition of stringent factor and tRNA. The tRNA release is suppressed when ATP is replaced by beta, gamma-imido adenosine 5'-triphosphate, 5'-AMP, or GTP.
Gram-preparative protein fractionation by isotachophoresis: isolation of human growth hormone isohormones.
Authors: Baumann G , Chrambach A
Published: May 2006

Steady-state stacking (isotachophoresis) provides a preparative method in zone electrophoresis for the isolation of proteins in gram amounts. Up to four components were separated in 1000-fold larger quantities than those used in conventional electrophoresis. Separation occurs in order of free electrophoretic mobility. Recovery is nearly quantitative. The method was shown to be capable of resolving isohormones of human growth hormone. This fractionation is representative of difficult terminal isolations in biology. The best results are obtained when few components are fractionated at a high load. The method uses simple, small-scale apparatus. It does not utilize spacer ampholytes.
DNA strand breaks, repair, and survival in x-irradiated mammalian cells.
Authors: Dugle D L , Gillespie C J , Chapman J D
Published: May 2006

The yields of unrepairable single-and double-strand breaks in the DNA of x-irradiated Chinese hamster cells were measured by low-speed neutral and alkaline sucrose density gradient sedimentation in order to investigate the relation between these lesions and reproductive death. After maximal single-strand remoining, at all doses, the number of residual single-strand breaks was twice the number of residual double-strand breaks. Both double-strand and unrepairable single-strand breaks were proportional to the square of absorbed dose, in the range 10-50 krad. No rejoining of double-strand breaks was observed. These observations suggest that, in mammalian cells, most double-strand breaks are not repairable, while all single-strand breaks are repaired except those that are sufficiently close on complementary strands to constitute double-strand breaks. Comparison with cell survival measurements at much lower doses suggests that loss of reproductive capacity corresponds to induction of approximately one double-strand break.
Localization by situ hybridization of amplified ribosomal DNA during Xenopus laevis oocyte maturation (a light and electron microscopy study).
Authors: Steinert G , Thomas C , Brachet J
Published: May 2006

The presence of ribosomal DNA has been demonstrated, by light and electron microscopy study of in situ hybridization with 125I-labeled ribosomal RNA, in the Feulgen-positive bodies which appear during maturation in the cytoplasm of Xenopus laevis oocytes. The ultrastructure of these bodies is described.
Localization of triiodothyronine in nerve ending fractions of rat brain.
Authors: Dratman M B , Crutchfield F L , Axelrod J , Colburn R W , Thoa N
Published: May 2006

Radioactive triiodothyronine reaching the rat brain after intravenous administration is rapidly and selectively taken up in the nerve ending fraction. A concentration gradient of radioactivity from brain cytosol to synaptosomes is observed at 5 min, increases linearly over the first hour, and is maintained for at least 10 hr. Radioactivity in the synaptosomes is due to triiodothyronine (90%) plus a single unidentified metabolite (10%). Approximately 85% of the synaptosomal radioactivity is released by osmotic disruption of the particles. The process of selective uptake, concentration, and retention of triiodothyronine in nerve terminals of the rat brain may be related to the sympathomimetic and behavior-altering effects of the thyroid hormones.
Involvement of escherichia coli dnaZ gene product in DNA elongation in vitro.
Authors: Wickner S , Hurwitz J
Published: May 2006

E. coli dnaZ gene product is required for conversion of phiX174, fd, and ST-1 single-stranded phage DNAs to duplex DNAs in vitro. This protein has been purified about 5000-fold. It functions in the elongation of RNA- or DNA-primed single-stranded DNA that is catalyzed by DNA polymerase III(DNA nucleotidyltransferase; deoxynucleosidetriphosphate: DNA deoxynucleotidyltransferase; EC 2.7.7.7) in conjunctions with two other E. coli protein preparations referred to as DNA elongation factors I and III. It also functions in similar reactions catalyzed by DNA polymerase II in combination with E. coli DNA binding protein and DNA elongation factors I and III.
A thermodynamic model of regulation: modulation of redox equilibria in camphor monoxygenase.
Authors: Sligar S G , Gunsalus I C
Published: May 2006

Regulation of biological phenomena occurs in all types of systems, being manifested in many different reaction types, from allosteric behavior in proteins, through modulation in energy and information transfer, to the control of growth and differentiation in cells, organelles, and organisms. In this communication, a modulation in oxidation/reduction potential via ligation of substrate and protein components in the camphor 5-exo-monoxygenase system is described in terms of a four-state system using as fundamental parameters the transition free energies between equilibrium states. This approach provides a concise description of the data and is useful for describing many aspects of regulatory phenomena.
Spectral differences between the alpha and beta heme groups within human deoxyhemoglobin.
Authors: Olson J S
Published: May 2006

The contributions of the alpha and beta heme groups to the absorbance change that accompanies the aggregation of hemoglobin subunits were measured by comparing the extinction changes produced by n-butyl isocyanide binding to deoxyhemoglobin A with those produced by binding of n-butyl isocyanide to the isolated chains. Almost the entire aggregation absorbance change is associated with the unliganded alpha subunits, which exhibit a 30% increase in molar extinction at 428 nm during tetramer formation. This marked spectral change indicates a substantial perturbation of the electronic properties of the alpha heme groups in going from the high-affinity, isolated chain state to the low-affinity, tetrameric state. The lack of a significant absorbance change as sociated with the beta heme groups implies that the change in reactivity of unliganded beta subunits produced by aggregation is not the result of a change in spin or coordination geometry of the iron atom, but rather involves primarily an alteration in the protein structure near the sixth coordination position.
Asymmetric orientation of phage M13 coat protein in Escherichia coli cytoplasmic membranes and in synthetic lipid vesicles.
Authors: Wickner W
Published: May 2006

At each stage of infection, the major coat protein of coliphage M13 binds to the E. coli cytoplasmic membrane with its antigenic site exposed to the cell exterior [Wickner, W. (1975) Proc. Nat. Acad. Sci. USA 72, 4749-4753]. This antigenic site is now shown to be at the amino-terminus of the protein. The amino-terminus of M13 coat protein is also found exclusively on the outside of dilauroyl or dimyristoyl lecithin vesicles, formed with coat protein by the cholate dilution technique [Racker, E., et al. (1975) FEBS Lett. 57, 14-18] near the lipid phase transition temperature. The basic carboxyterminus of the coat protein is exclusively on the inside of these vesicles. Vesicles of M13 coat protein and dimyristoyl lecithin when formed below the lipid phase transition temperature have both ends of the coat protein exposed to the vesicle exterior. The asymmetry of a membrane protein can, therefore, be established in the absence of other proteins and of lipid asymmetry; it depends on the physical state of the lipid phase. The factors which cause asymmetry in this model system may affect the distribution of proteins in biological membranes.
mRNA-dependent synthesis of authentic precursor to human placental lactogen: conversion to its mature hormone form in ascites cell-free extracts.
Authors: Szczesna E , Boime I
Published: May 2006

Messenger RNA derived from term placenta directs the synthesis of human placental lactogen (hPL, molecular weight 22,200) in an ascites 30,000 X g post-mitochondrial supernate (S-30). When the S-30 is fractionated into ribosome and cell-sap (S-100) fractions, and these are recombined for incubation, term placental mRNA directs the synthesis of a protein with a molecular weight of 25,000. This protein contains authentic hPL tryptic peptides. This suggested that during the separation of ribosomes and S-100 a component responsible for cleavage was lost. A 1.0 M sucrose cushion was used for the preparation of ribosomes and S-100 and membranous material accumulated at the sucrose interphase. When this membrane fraction was added back to the ribosome-S-100 system only hPl was formed. Cleavage was greatest when membranes were added within the first few minutes of incubation. In a run-off system composed of term polysomes, ascites S-100, and the inhibitor of initiation, pactamycin, the 25,000 molecular weight material, referred to as pre-hPL, was also synthesized. These data strongly suggest that (i) pre-hPL is an authentic percursor to hPL, (ii) cleavage of the precursor primarily occurs on nascent, ribosome-bound peptide chains, and (iii) pre-hPL is the primary gene product.
Dimethylsulfoxide-induced differentiation and hemoglobin synthesis in tissue cultures of rat erythroleukemia cells transformed by 7,12-dimethylbenz(a)anthracene.
Authors: Kluge N , Ostertag W , Sugiyama T , Arndt-Jovin D , Steinheider G , Furusawa M , Dube S K
Published: May 2006

Permanent cell lines from transplantable tumors from 7, 12-dimethylbenz(a)anthracene-induced erythroleukemia of the rat were established. These cell lines maintain their erythroid nature. Erythroid differentiation can be induced by dimethylsulfoxide. This is shown by decrease in cell size, appearance of red and benzidine positive cells, and induced synthesis of four out of six adult globin chains.
Clathrin: a unique protein associated with intracellular transfer of membrane by coated vesicles.
Authors: Pearse B M
Published: May 2006

Coated vesicles have been purified from brain, adrenal medulla, and a nonsecreting lymphoma cell line. A single major protein species, clathrin, with an apparent molecular weight of 180,000, forms the coat of all these vesicles. Peptide mapping suggests that the amino acid sequence of clathrin is conserved, irrespective of tissue or species studied. Coated vesicles of different sizes are found. The coats are constructed with variable numbers of clathrin subunits, arranged in closed networks of hexagons and pentagons. The amount of clathrin in lymphoma cells suggests that coated vesicles transfer substantial amounts of membrane within cells, not necessarily in association with a secretory process.
Evidence for circularization of the avian oncornavirus RNA genome during proviral DNA synthesis from studies of reverse transcription in vitro.
Authors: Collett M S , Faras A J
Published: May 2006

The RNA-directed DNA polymerase (deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase EC 2.7.7.7) of avian oncornavirus requires a tryptophan tRNA (tRNATrp) primer molecule located close to the 5' end of the viral RNA genome for the initiation of DNA synthesis in vitro. In this communication we demonstrate that the DNA product, transcribed from avian myeloblastosis virus (AMV) 35S RNA containing only tRNATrp as primer, is located also at the 5' end of the RNA genome. More importantly, we demonstrate that these 5' terminal DNA transcripts contain nucleotide sequences complementary to the 3' end of the genome. We have interpreted these results to mean that the genome. We have interpreted these results to mean that the 3' and 5' termini of the AMV 35S RNA genome become juxtaposed with each other either before or immediately after DNA synthesis has begun. These results are discussed in regard to the mechanism for synthesis of the circular forms of oncornavirus proviral DNA.
Solar abundance of osmium
Authors: Jacoby George , Aller Lawrence H.
Published: May 2006

The abundance parameter, log
gfA
, where
g
is the statistical weight of the lower level,
f
is the oscillator strength, and
A
is the abundance (by numbers of atoms with respect to hydrogen), has been derived for three lines of osmium by a method of spectrum synthesis. An apparent discordance of the derived abundance with that found from the carbonaceous chondrites is probably to be attributed primarily to errors in the
f
-values, and blending with unknown contributors.
Membrane penicillinase of Bacillus licheniformis 749/C:sequence and possible repeated tetrapeptide structure of the phospholipopeptide region.
Authors: Yamamoto S , Lampen J O
Published: May 2006

The membrane penicillinase (EC 3.5.2.6; penicillin amido-beta-lactamhydrolase) of Bacillus licheniforis 749/C, which appears to be an intermediate in the formation of the exoenzyme, is a phospholipoprotein that carries an NH2-terminal chain of 24 amino acids (only serine, glycine, aspartic acid, asparagine, glutamic acid, and glutamine) and a phosphatidylserine that is not present in the exoenzyme.
The neurospora plasma membrane ATPase is an electrogenic pump.
Authors: Scarborough G A
Published: May 2006

Biochemicalical evidence is presented which demonstrates that the Neurospora crassa plasma membrane ATPase (ATP phosphohydrolase, EC 3.6.1.3) is an electrogenic pump. The electrical potential across the Neurospora plasma membrane, as monitored by [14C]SCN- uptake by isolated Neurospora plasma membrane vesicles, is markedly increased interior positive under conditions of ATP hydrolysis catalyzed by plasma membrane ATPase. [14C]SCN- uptake by the vesicles is minimal in the presence of Tris phosphate, Tris phosphate plus Mg+2, Tris ADP plus Mg+2, and Tris ATP, but is markedly stimulated in the presence of Tris ATP plus Mg+2.
Replication of mycoplasmavirus MVL51: Attachment of MVL51 parental DNA to host cell membrane
Authors: Das Jyotirmoy , Maniloff Jack
Published: May 2006

The replication of the single-stranded circular DNA of MVL51 mycoplasmavirus has been studied with respect to the roles of free and membrane-associated viral DNA intermediates. Replication involves the formation of parental replicative intermediate (RF) molecules on, at most, two to three membrane sites per cell, symmetric RF replication at the membrane, and apparent asymmetric RF replication in the cytoplasm leading to single-stranded progeny chromosomes.
Synthesis of an R plasmid protein associated with tetracycline resistance is negatively regulated.
Authors: Yang H L , Zubay G , Levy S B
Published: May 2006

Synthesis of proteins encoded by the R222 plasmid was observed in a DNA-directed cell-free system and the products were compared to those plasmid proteins synthesized in Escherichia coli minicells. A greater number of plasmid-specified proteins was detected in the in vitro system than in the minicell, suggesting the presence of control factors for plasmid gene expression in the minicell. Synthesis of a newly detected plasmid protein (TET protein) is induced by tetracycline in minicells containing tetracycline-resistant plasmids, including R222, and this induced synthesis correlates with induced host resistance to the drug. This TET protein was synthesized in vitro from R222 DNA in the absence of tetracycline, indicating that no positive regulatory role for tetracycline is required for the protein's synthesis. TET proteon synthesis was inhibited in vitro when cell-free extracts prepared from cells containing the R222 plasmid were used.
High in vivo rates of methionine biosynthesis in transformed human and malignant rat cells auxotrophic for methionine.
Authors: Hoffman R M , Erbe R W
Published: May 2006

Unlike normal cells, malignant rat and two simian virus 40-transformed human cell lines can neither grow nor survive in B12-and folate-supplemented media in which methionine is replaced by homocysteine. Yet three lines of evidence indicate that the malignant and transformed cells synthesize large amounts of methionine endogenously through the reaction catalyzed by 5-methyltetrahydropteroyl-L-glutamate; L-homocysteine S-methyltransferase (EC 2.1.1.13). (1) The activities of this methyltransferase were comparable in extracts of malignant and normal cells. (2) The uptake of radioactive label from [5-14C]methyltetrahydropteroyl-L-glutamic acid (5-Me-H4PteGlu) was at least as great in the malignant cells as in the normals and was nearly totally dependent on the addition of homocysteine, the methyl acceptor; furthermore, 59-84% of the label incorporated by cells was recovered as methionine.
Coordinate regulation of the synthesis of eukaryotic ribosomal proteins.
Authors: Gorenstein C , Warner J R
Published: May 2006

We have developed a method of r the direct measurement, in eukaryotic cells, of the synthesis of ribosomal proteins, irrespective of the synthesis of ribosomes. In this way the synthesis of ribosomal proteins has been examined in mutant strains of Saccharomyces cerevisiae, which are unable to synthesize ribosomes under nonpermissive conditions. The results suggest that the synthesis of more than 40 ribosomal proteins is under coordinate control. Under nonpermissive conditions,the synthesis of each h protein declines exponentially to a basal level which is 10-20% fo normal. The kinetics of that decline suggest that an early, if not primary, result of the nonpermissive conditions is the cessation of production of new mRNA for eac of the ribosomal proteins. The coordinate regulation appears not to be influenced directly by the rate of transcription of ribosomal precursor RNA.
A new immunoglobulin variant: gamma3 heavy chain disease protein CHI.
Authors: Frangione B
Published: May 2006

Protein CHI is a defective human gamma3 heavy chain immunoglobulin with a deletion encompassing a portion of the variable and constant regions. Joining of the two pieces takes place at the beginning of an extra fragment (Fh) in the constant region where repetitive sequences are found, apparently as the result of gene duplications and/or unequal crossover between gamma genes. It is postulated that a 45 nucleotide fragment is the repetitive unit coding for the extra fragment.
Bacteriophage T5-induced endonucleases that introduce site-specific single-chain interruptions in duplex DNA.
Authors: Rogers S G , Rhoades M
Published: May 2006

Four site-specific endodeoxyribonucleases have been partially purified from extracts of bacteriophage T5-infected Escherichia coli by gel filtration and affinity chromatography on single- and double-stranded DNA. The enzymes were detected and characterized by agarose gel electrophoresis of alkali-denatured digestion products. None of the four is found in uninfected cells. In the presence of a divalent cation, all four endonucleases make ligase-repairable, single-chain interruptions at specific sites in the duplex DNA of several bacteriophages (lambda, T7, and T5) and a mammalian virus (adenovirus 2). These activities are not stimulated by ATP. None of the four is active on single-stranded DNA. The fragments produced by each enzyme from ligase-repaired T5 DNA do not correspond to those derived from mature T5 DNA. Each of the enzymes is able to cleave the intact strand of T5 DNA.
Stimulation of prostaglandin E synthesis in cultured human umbilical vein smooth muscle cells.
Authors: Alexander R W , Gimbrone M A
Published: May 2006

Cultured human umbilical vein smooth muscle cells secreted 1.26 +/- 0.20 mug of immunoreactive prostaglandin E (iPGE) per mg of cell protein per 24 hr (mean +/- SEM). In indomethacin, an inhibitor of prostaglandin synthesis, abolished greater than 95% of this basal iPGE production (ID50 = 1.8 nM).
Evolution of continuous variation: direct approach through joint distribution of genotypes and phenotypes.
Authors: Cavalli-Sforza L L , Feldman M W
Published: May 2006

The evolutionary dynamics of the joint distribution of genotypes and phenotypes is studied. The model, originally devised to study the joint effects of Mendelian and other types of transmissions, provides results of interest also to the theory of direct Mendelian transmission with natural selection. Assuming bivariate normal distributions, it is shown that in the latter case genotypic and phenotypic means and variances, and genotype-phenotype correlation can be expressed recursively as functions of the parameters for the selection, environmental, and mutation variance. Equilibria and rates of approach for these moments are calculated. It is also proved that in the presence of selection the heritability,defined as the ratio of expected genotypic to expected phenotypic variance after selection, is greater than that before selection by a predictable amount and that it can be greater than unity.
Abnormal ornithine carbamoyltransferase in mice having the sparse-fur mutation.
Authors: DeMars R , LeVan S L , Trend B L , Russell L B
Published: May 2006

Mice with the X-chromosomal sparse-fur (spf) mutation frequently have urinary bladder stones composed mostly of orotic acid, which was identified by the following criteria: ultraviolet and infrared absorption, spectra, chromatographic behavior, melting point, and reactivity in a specific color test. This clue led to the discovery that spf-bearing mice have an abnormal form of liver ornithine carbamoyltransferase (carbamoylphosphate:L-ornithine carbamoyltransferase, EC 2.1.3.3). Normal ornithine carbamoyltransferase has maximum activity at pH 7.6-8.0 and 80% of maximum activity at pH 10.0.
The effect of main artery occlusion of one kidney on blood pressure of dogs.
Authors: Goldblatt H , Haas E , Klick R L , Lewis L V
Published: May 2006

Occluding the main artery of one kidney in each of six dogs resulted in an average increase in the renin concentration of the peripheral blood from the original 0.040 to 0.198 milliunit/ml of serum. During the same time (3-4 days), the occlusion also resulted in a significant rise of directly measured mean systemic blood pressure from an average basal level of 104 to 139 mm Hg.
High dimensional cohomology of discrete groups
Authors: Brown Kenneth S.
Published: May 2006

For a large class of discrete groups Γ, relations are established between the high dimensional cohomology of Γ and the cohomology of the normalizers of the finite subgroups of Γ. The results are stated in terms of a generalization of Tate cohomology recently constructed by F. T. Farrell. As an illustration of these results, it is shown that one can recover a cohomology calculation of Lee and Szczarba, which they used to calculate the odd torsion in
K
3
(Z).
Opioid activity of a peptide, beta-lipotropin-(61-91), derived from beta-lipotropin.
Authors: Cox B M , Goldstein A , Hi C H
Published: May 2006

The pituitary peptide beta-lipotropin displays essentially no opoid activity in a preparation of guinea pig ileum or in the opiate receptor binding assay. However, a fragment, beta-lipotropin-(61-91), with the enkephalin sequence (Tyr-Gly-Gly-Phe-Met) at its NH2-terminus, has typical opioid effects in these two assays.
Crystalline semisynthetic ribonuclease-S'.
Authors: Pandin M , Padlan E A , DiBello C , Chaiken I M
Published: May 2006

Crystals of solid phase-derived semisynthetic ribonuclease-S' were prepared and compared with those for native ribonuclease-S' and -S. The semisynthetic species used was the noncovalent complex of synthetic fragment-(1-20), corresponding to residues 1 through 20 of bovine pancreatic ribonuclease-A (ribonucleate 3'-pyrimidino-oligonucleotidohydrolase, EC 3.1.4.22), and native ribonuclease-S-(21-124); the fragment containing residues 21 through 124 of ribonuclease-A. This semisynthetic complex was completely active enzymatically, was homogeneous as judged by polyacrylamide gel electrophoresis, and had no greater than trace amounts of excess ribonuclease-s(21-124) as judged by affinity chromatography. Crystallization of both semisynthetic and native ribonuclease-s' at pH 5.3 resulted in well-formed crystallseater than trace amounts of excess ribonuclease-S-T21-124) as judged by affinity chromatography. Crystallization of both semisynthetic and native ribonuclease-S' at pH 5.3 resulted in well-formed crystals with the symmetry of space group P3121 and unit cell dimensions a=b=44.82, c=97.3 A. This crystal form corresponds to the Y form of native ribonuclease-S previously reported [Wyckoff et al. (1967) J. Biol. Chem. 242, 3749-3753]. X-ray diffraction patterns of the crystals were indistinguishable, indicative of the structural identity of semisynthetic and native ribonuclease-S'.
Amino acid sequence at the FdUMP binding site of thymidylate synthetase.
Authors: Bellisario R L , Maley G F , Galivan J H , Maley F
Published: May 2006

Cyanogen bromide treatment of thymidylate synthetase of Lactobacillus casei, which had been converted to a ternary complex with [2-14c] FdUMP and 5,10-methylene-tetrahydrofolate followed by S-carboxymethylation, yielded at least four visible peptide bands, the largest with a molecular weight of about 13,000, on polyacrylamide gel electrophoresis in sodium dodecyl sulfate-urea. Identical results were obtained with enzyme that had all four of its cysteinyl residues S-carboxymethylated with iodo [I-14C] acetate in the absence of FdUMP and cofactor. In each case, only the second band from the top of the gel (CN2), with an approximate molecular weight of 10,000= was labeled. Analysis of CN2 that had been labeled with [2-14C] FdUMP and nonradioactive iodoacetate and of that labeled only with iodo[1-14C] acetate revealed that their amino-acid contents were almost identical except for the presence of two S-carboxymethyl (Cm)-cysteinyl residues in the latter peptide and only one in FdUMP-CN2. A nonapeptide was isolated from (Cm)2-CN2 after chymotrypsin digestion that contained the following sequence by dansyl-Edman analysis: Ala-Leu-Pro-Pro-[Cm-Cys]-His-Thr-Leu-Tyr. This peptide was found to be located on the NH2-terminal end of CN2. Automatic sequence analysis of the first 13 residues of (Cm)2-CN2 and of the FdUMP-containing CN2 yielded identical results except for the fifth, or cysteinyl, residue, which could not be identified in the latter peptide. These findings strongly suggest that FdUMP is linked to a cysteinyl residue in thymidylate synthetase that has been inactivated irreversibly by this nucleotide.
Sodium-stimulated alpha-aminoisobutyric acid transport by membrane vesicles from simian virus-transformed mouse cells.
Authors: Hamilton R T , Nilsen-Hamilton M
Published: May 2006

Uptake of alpha-aminoisobutyric acid, by membrane vesicles derived principally from the plasma membrane and endoplasmic reticulum of mouse 3T3 cells transformed by simian virus 40, is stimulated by sodium chloride. Both in the presence and absence of Na+ uptake is time-dependent and osmotically sensitive. The Na+-stimulated uptake is inhibited by other amino acids. The kinetics of transport of alpha-aminoisobutyric acid are shown to be biphasic both in whole cells and in the membrane vesicles. Only the high affinity system is stimulated by sodium in the membrane vesicles. These results demonstrate that observations made on living cells correlate with observations made on isolated membrane vesicles, and indicate that these membrane vesicles have retained the cellular amino acid transport system functionally intact.
Size of primary transcripts in Ehrlich ascites cells as measured by tetraphosphate determination.
Authors: Schmincke C D , Herrmann K , Hausen P
Published: May 2006

A method for the quantitation of 5"-tetraphosphate ends in 32P-labeled RNA has been developed. The tetraphosphate content of different RNA fractions obtained from Ehrlich ascites cells labeled with 32P for different lengths of time has been determined. Ribosomal RNA and poly(U)-binding RNA, labeled for long periods, (mRNA) lack 5'-terminal tetraphosphate. 5S RNA, pulse labeled 4-5S RNA, and poly(U)-binding hnRNA (heterogeneous nuclear RNA) do contain tetraphosphate. From the amount of the tetraphosphate, molecular weight data can be calculated for these RNA fractions which agree with independent determinations by denaturing gel electrophoresis. The results demonstrate that the majority of the poly(A) containing hnRNA molecules are small (less than 28S) and contain the tetraphosphate of the primary transcript. Therefore, they do not originate from the 3'-end of large molecules by processing events.
Protein synthesis and actin heterogeneity in calf muscle cells in culture.
Authors: Whalen R G , Butler-Browne G S , Gros F
Published: May 2006

Pulse-labeled cytoplasmic proteins from cultured fetal calf-muscle cells at various stages of development were analyzed by one- and two-dimensional gel electrophoresis. The high resolution of the two-dimensional technique allows the determination of those protein species that begin to be synthesized after cell fusion. In addition, actin has been found to exist in three forms possessing similar biochemical properties and identical molecular weights but having slightly different isoelectric points. Two of the forms are found in prefusion dividing myoblasts and also in cultured kidney cells. The third form is the only one found in fetal muscle tissue and is predominant in cultures of fused muscle cells. Thus, it would seem that actin can exist in several isozymic forms of which one is specific to fused muscle tissue.
Selenium is an essential trace nutrient for growth of WI-38 diploid human fibroblasts.
Authors: McKeehan W L , Hamilton W G , Ham R G
Published: May 2006

The trace element selenium is essential for clonal growth of diploid fibroblasts from human fetal lung (WI-38) in media containing small amounts of serum protein. Maximum growth stimulation is obtained when 30 nM neutralized selenious acid is added to a synthetic medium containing 1.5 mg/ml of dialyzed fetal bovine serum protein (equivalent to a 3% serum concentration). Serum appears to be a source of selenium in most culture media, since higher concentrations of serum protein or whole serum mask the selenium requirement of WI-38 cells. Selenium is also required by a Chinese hamster cell line that can be grown in a protein-free synthetic culture medium.
Immunologic evidence that the gene for L-gulono-gamma-lactone oxidase is not expressed in animals subject to scurvy.
Authors: Nishikimi M , Udenfriend S
Published: May 2006

L-Gulono-gamma-lactone oxidase (L-gulono-gamma-lactone:oxygen 2-oxidoreductase, EC 1.1.3.8) is the enzyme that catalyzes the terminal step of L-ascorbic acid biosynthesis in mammalian liver. The absence of the oxidase activity in primates and guinea pigs is the reason why these animals are subject to scurvy, which must be considered an inborn error of metabolism. Attempts were made to determine if a protein immunologically crossreactive with L-gulono-gamma-lactone oxidase is present in these animals. Detergent-solubilized microsomal preparations from guinea pig and African green monkey liver did not precipitate the antisera directed to either rat or goat enzyme, nor did any of the other cell fractions obtained from guinea pig liver react with either antiserum. No crossreactive protein was detectable in guinea pig microsomes even with the sensitive procedure or micro-complement fixation. On the other hand, extracts of all 10 other mammalian (4 orders) liver microsomes tested were shown to contain L-gulono-gamma-lactone oxidase activity that did crossreact with antibodies to the rat and goat enzymes. One explanation of these findings is that, in the guinea pig, and perhaps in primates too, the structural gene for L-gulono-gamma-lactone oxidase is not expressed.
Heredity of the GIX thymocyte antigen associated with murine leukemia virus: segregation data simulating genetic linkage.
Authors: Stockert E , Boyse E A , Sato H , Itakura K
Published: May 2006

The GIX antigen is a feature of the gp70 envelope glycoprotein of murine luekemia virus (MuLV). This GIX-gp70 molecule is found on the thymocytes of some (GIX+) strains of mice, where its expression is controlled by two mendelian genes, Gv-1 and Gv-2. Previous recombination data involving the prototype GIX+ strain 129 indicated that the H-2 (chromosome 17) and Gv-1 loci are linked, at a distance of 36 units from one another. New data indicate that the association of H-2 and GIX phenotypes is an example of quasi-linkage, evidently dependent in this instance on heterozygosity at a locus or loci in the vicinity of H-2. Other previous recombination data, involving the GIX+ strain AKR, had indicated that the Gpd-1 (chromosome 4) and Gv-1 loci are linked at a distance of 19 units from one another. New data from other crosses show that this association of Gpd-1 (glucose-6-phosphate dehydrogenase 1) and GIX phenotypes also constitutes quasi-linkage, evidently due to heterozygosity at the Fv-1 locus. An important theoretical consequence of quasi-linkage in general is that it should enhance the heritability of particular constellations of unlinked genes, and so influence population structure. Our new data are discussed from the viewpoint that MuLV genomes are apparently concerned in quasi-linkage, and therefore by the same arguments may influence the genetic structure of populations. This in turn may strengthen the view that integrated MuLV genomes are not simply intruded into a self-sufficient cellular genome, but are themselves elements of the cellular genome with primary functions, perhaps in reproduction or embryogenesis.
Fusion of protoplasts of Bacillus megaterium.
Authors: Fodor K , Alföldi L
Published: May 2006

Protoplasts of two doubly auxotrophis strains of Bacillus megaterium were fused by nascent calcium phosphate or by polyethylene glycol treatment, and then allowed to revert to bacillary form on selection media. The colonies formed were analyzed and found to be mixed populations of individual bacteria apparently containing parental, recombinant, and segregating genotypes. The evidence suggested that segregation was transitory, lasting only for a few clonings and reisolations.
Fusion of bacterial protoplasts.
Authors: Schaeffer P , Cami B , Hotchkiss R D
Published: May 2006

Prototrophic Bacillus subtilis cells can be formed in the presence of DNase as a result of cell fusion occurring in mixed populations of protoplasts derived from two parental strains which are both nutritionally-complementing and polyauxotrophic. No prototrophs ever appear from mixed nonprotoplasted bacteria, or from the auxotrophic parental protoplasts plated separately. The frequency of prototroph formation, which is appreciable only when the mixed protoplasts are exposed to polyethylene glycol treatment, may exceed 1 X 10(-4) of the total protoplast population initially present, which is 1 to 4 X 10(-3) of those protoplasts which reverted to the bacillary form. It is strongly dependent on the number and chromosomal location of the markers used in the selection of the prototrophs, and it is unaffected when either one of the parental strains bears the phage phi105 in the inducible prophage state. No auxotrophic bacteria, parental or otherwise, were found as segregants from repeatedly isolated protrotrophic clones growing in a nonselective medium. Unselected markers segregate among the selected recombinants. It is concluded that the observed formation of prototropic bacteria is due to protoplast fusion, a process which does not induce prophage development, and that the only stable products of the resulting diploid state are haploid recombinants.
Regulation of transcription factor rho and the alpha subunit of RNA polymerase in Escherichia coli B/r.
Authors: Blumenthal R M , Reeh S , Pedersen S
Published: May 2006

Transcriptional termination factor rho, the alpha subunit of RNA polymerase (RNA nucleotidyltransferase nucleosidetriphosphate: RNA nucleotidyltransferase, EC 2.7.7.6), and ribosomal protein S6 were resolved from whole-cell extracts of E. coli B/r by a high-resolution, two-dimensional polyacrylamide gel electrophoretic technique, and were identified through coelectrophoresis with the purified proteins. The regulation of rho, alpha, and S6 was studied, in steady-state cultures of E. coli B/r growing at rates ranging from 0.6 to 2.1 generations per hr, through the use of this gel technique and a double radioisotope labeling procedure. The regulatory patterns of rho and alpha are distinct from, but similar to, one another. Neither rho nor alpha shows the sharply increasing levels with increasing growth rate shown by the ribosomal proteins was exemplified by S6. The difference between the levels of rho and alpha, on the one hand, and S6, on the other, is most pronounced during rapid growth. The regulatory pattern of alpha is interesting, given the recent suggestion that the gene coding for alpha is contranscribed with genes coding for ribosomal proteins.
Characterization of the collagen synthesized by endothelial cells in culture.
Authors: Howard B V , Macarak E J , Gunson D , Kefalides N A
Published: May 2006

[14C]Proline and [14C]lysine were incorporated into collagen by cultures of endothelial cells derived from calf aortae. The isomer 3-hydroxy[14C]proline accounted for 10% of the total hydroxy[14C]proline in the collagen isolated from the medium. Approximately 81% of the hydroxy[14C]lysine isolated from the medium was glycosylated, and 91% of the glycosylated hydroxy[14C]lysine was in the form of the disaccharide glucosylgalactose. Gel filtration chromatography or acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate indicated that the initially synthesized peptide chain of [14C]collagen had a molecular weight of about 135,000; after pepsin digestion this was converted to 115,000. The ratio of hydroxy[14C]proline to total [14C]proline x 100 in the pesin-resistant fraction was 59. When examined by immunofluorescence microscopy, the endothelial cultures stained positively with antiserum to (Type IV) collagen from basement membrane of bovine anterior lens capsule. The data indicate that cultured endothelial cells derived from calf aortae synthesize collagen that resembles that of basement membrane collagen.
Phylogenetic origins of immune recognition: lymphocyte surface immunoglobulins in the goldfish, Carassius auratus.
Authors: Warr G W , DeLuca D , Marchalonis J J
Published: May 2006

Membrane immunoglobulin (Ig) of splenocytes and thymocytes of the goldfish, Carassius auratus, was demonstrated by indirect fluorescent-antibody techniques. Observations on shedding and resynthesis indicated that the thymocyte Ig was endogenously produced. The lymphocyte surface proteins were radioiodinated using the lactoperoxidase-catalyzed reaction, and the labeled Ig molecules were isolated by specific precipitation and analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The IgM-like membrane Igs of splenocytes and thymocytes were shown to differ in their ease of solubilization with nonionic detergent, and in the sodium dodecyl sulfate/electrophoretic mobility of their heavy chains. The significance of these observations for the evolution of T-cell recognition is discussed.
Interactions between nutritional factors and drug biotransformations in man.
Authors: Alvares A P , Anderson K E , Conney A H , Kappas A
Published: May 2006

This study was undertaken to examine the influence of nutritional factors on the activity of the mixed function oxidase system in man, which is cytochrome P-450 dependent. Three normal volunteers were fed a low carbohydrate-high protein diet for 2 weeks, followed by a high carbohydrate-low protein diet for the follwoing 2 weeks. At the end of each test diet period, the plasma elimination rates of antipyrine and theophylline were determined. The mean plasma half-life for antipyrine was 17.5 hr on the high carbohydrate-low protein diet and 9.2 hr on the low carbohydrate-high protein diet. The mean plasma half-life for theophylline was 8.9 hr on the high carbohydrate-low protein diet and 5.9 hr on the low carbohydrate-high protein diet. These data demonstrate marked influences of dietary carbohydrate and/or protein ingestion on oxidative biotransformation of drugs in man.