bluuebunny/crossref_metadata_2025 huggingface dataset:
RESPIRATORY CONTROL AND DEHYDROGENASE ACTIVITY
Authors: Cereijo-Santaló Roberto
Published: December 2009

A comparative study has been made of the stimulation of respiration by ADP or by 2,4-dinitrophenol in liver mitochondria incubated with different substrates of NAD-dependent enzymes.It has been found that the degree of stimulation of respiration by ADP or by 2,4-dinitrophenol increased with the number of dehydrogenases involved in the oxidation of the substrate. The respiratory stimulation was greater with higher substrate concentrations. This suggests that the hydrogen pressure produced by dehydrogenase activity was, in each case, the factor which determined the degree of respiratory stimulation.When the concentration of substrate decreased, the stimulation of respiration diminished proportionally, and at very low substrate concentrations was depressed, the rate of respiration in the presence of ADP or 2,4-dinitrophenol being lower than in their absence. Such inhibition of respiration could be reduced or even abolished by increasing the concentration of substrate in the medium. Therefore, not only the degree of respiratory response to ADP or to 2,4-dinitrophenol but also its stimulatory or inhibitory character depended upon the dehydrogenase activity.The concentration of ADP or 2,4-dinitrophenol necessary to induce a maximal respiratory stimulation also increased with the number of dehydrogenases involved in the oxidation of the substrate.
CYCLIC CHANGES IN THE ACTIVITIES OF PLASMA ACID AND ALKALINE PHOSPHATASES DURING EGGSHELL CALCIFICATION IN THE DOMESTIC FOWL
Authors: Taylor T. G. , Williams Ann , Kirkley Jean
Published: December 2009

Acid and alkaline phosphatases were assayed in 240 samples of plasma taken from laying hens at various stages of the laying cycle. The activity of both enzymes was minimal shortly after oviposition. Acid phosphatase values increased rapidly during the first 10 hours of shell formation and then more slowly, reaching a peak when shell calcification was completed. A precipitous fall occurred about the time of oviposition. The activity of alkaline phosphatase increased rapidly after oviposition, reaching a maximum 8–9 hours later when calcification of the next egg had been in progress 4–5 hours, and thereafter falling steadily throughout the main period of shell formation. No systematic changes were observed in the levels of either enzyme at successive bleedings when shell calcification was not in progress. Striking relations were observed between the cyclic changes in the levels of phosphatase activity in the plasma and the changes known to occur in the cell population of the medullary bone, the level of acid phosphatase paralleling the osteoclast activity and the alkaline phosphatase paralleling the osteoblast activity. It is suggested that the osteoclasts and osteoblasts release their respective phosphatase during their active metabolic phases.
FATTY ACIDS IN DROSOPHILA MELANOGASTER: I. THE QUALITATIVE ANALYSIS OF UNSATURATED FATTY ACIDS IN DROSOPHILA MELANOGASTER
Authors: Kato Mikio
Published: December 2009

The pupal lipids of Drosophila melanogaster were mercurated and the unsaturated fatty acids were separated by reversed-phase paper chromatography. Comparative quantitative analyses were made by means of densitometry and by comparison of extinction coefficients of absorption. In all the strains tested, the following acids were commonly found: oleic, palmitoleic, myristoleic, lauroleic, linolenic, linoleic, and arachidonic acids.Within a particular strain, the content of oleic and palmitoleic acids varied with that of linoleic and linolenic acids, respectively. Based on the contents of these unsaturated fatty acids, the strains can be sorted into three groups: group A, the wild types (Tokyo, Oregon, Oregon-RS, Saikyo, and Canton-S); group B, vermilion (v), cinnabar (cn), scarlet (st), clot (cl), sepia (se), and brown (bw); and group C, white (w), along with the compounds v;bw, cn;bw, and bw;st, all of which represent different genetic blocks to eye pigment formation.
MITOCHONDRIA FROM LIPOMYCES LIPOFER
Authors: Heick H. M. C. , Stewart H. B.
Published: December 2009

Protoplasts of Lipomyces lipofer were ruptured by decompression in a French pressure cell. A particulate fraction sedimenting at 17,000 × g in saline or sucrose media contained the bulk of the substrate-dependent oxidative activity and was capable of phosphorylation. Particle fractions isolated in sucrose required supplementation with ATP and Mg2+while fractions from saline isolations required, in addition, NAD and cytochrome c. NADP and thiamine pyrophosphate had small or negligible effects in the presence of the other cofactors. Oxidative phosphorylation occurred most efficiently in particles isolated in sucrose, but in no case did the P/O ratio exceed 1.6. Electron microscopic examination of the sucrose-isolated fraction showed it to be a relatively homogeneous preparation of mitochondria which appear more "native" after incubation with substrate than immediately after isolation.
A HISTONE-LIKE FRACTION BOUND TO LIPID IN STAPHYLOCOCCUS EPIDERMIDIS
Authors: Bergh A. K. , Webb S. J. , McArthur C. S.
Published: December 2009

The protein moiety of a proteolipid extracted from Staphylococcus epidermidis has been isolated. It was found to be highly basic, with lysine accounting for 25% of its amino acids. In vitro experiments showed that it readily formed a complex with DNA or RNA. The possible role of this protein fraction in cell stability and the Gram staining reaction is discusssed.
THE UTILIZATION OF CARBON-1 COMPOUNDS BY PLANTS: II. THE FORMATION AND METABOLISM OF FORMATE BY HIGHER PLANT TISSUES
Authors: Cossins E. A. , Sinha S. K.
Published: December 2009

Tissue slices of carrot root and sunflower cotyledons readily produce formate-C14when incubated with glyoxylate-1,2-C14and glycine-2-C14solutions. Formate-C14feeding experiments using a wide variety of higher plant tissues have shown that this compound is readily oxidized to carbon dioxide. This oxidation probably involves a formic dehydrogenase system which has been demonstrated to occur in several of the tissues. Large amounts of formate-C14were also incorporated into serine, methionine, and methionine sulfoxide. Degradations of the serine produced from formate-C14showed that the bulk of the C14was present in the 3 position. The incorporation of formate into serine by radish cotyledons was stimulated under anaerobic conditions and by additions of glycine. Synthesis of methionine and methionine sulfoxide from formate-C14was stimulated by additions of homocysteine. The results are interpreted as an indication that formate-C14can be oxidized to carbon dioxide by formic dehydrogenase and can serve as a precursor of carbon-1 units that are to be utilized for the biosynthesis of serine and methionine.
ALDOLASE AND "AMINOACYL ARYLAMIDASE" IN THE DENERVATED RAT GASTROCNEMIUS MUSCLE
Authors: Graff G. L. A. , Hudson A. J. , Strickland K. P.
Published: December 2009

Activities of the two enzymes aldolase and "aminoacyl arylamidase" (formerly called leucine aminopeptidase) were determined in rat gastrocnemius muscle 5, 15, and 30 days after denervation. Expression of both activities per unit weight and activities per whole muscle as a percentage of the contralateral control revealed a number of interesting changes. The concentrations of aldolase and "aminoacyl arylamidase" in the contralateral control gastrocnemius muscle were, respectively, 3.07 I.U. (S.E.M. ± 0.18 for 42 animals) and 0.0577 I.U. (S.E.M. ± 0.0030 for 42 animals) per 100 mg wet weight. Both the concentration per unit weight and the content per whole muscle of aldolase were not affected 5 days after neurotomy. At later stages of denervation large losses in aldolase occurred, with the concentration per unit weight being 43% of the control at 15 days and 25% at 30 days. On a whole muscle basis the loss in aldolase was higher than the loss in muscle mass (−85% versus −56% at 15 days and −93% versus −74% at 30 days). The concentration of "aminoacyl arylamidase" per unit weight increased in the denervated muscle (155%, 206%, and 207% of the contralateral control at 5, 15, and 30 days, respectively). The "aminoacyl arylamidase" content of the whole denervated muscle was increased (+ 24%) 5 days after neurotomy; in the later stages of denervation the content decreased, but the decrease was less than that for the muscle mass (−27% versus −56% at 15 days and −43% versus −74% at 30 days).The rapidity and magnitude of the losses of aldolase suggest that denervation of muscle has brought about an increased permeability to this enzyme. The findings for "aminoacyl arylamidase" might be explained on the basis that, immediately after neurotomy, there exists a positive balance between synthesis and the combined effects of catabolism and efflux of the enzyme which changes to a negative balance in the later stages of denervation.
INHIBITION OF IN VITRO ACETOACETATE FORMATION: AN ACID PHOSPHOHYDROLASE
Authors: Caldwell Ian C. , Drummond George I.
Published: December 2009

The rate of formation of acetoacetate in vitro by tissue extracts from acetyl phosphate and coenzyme A in the presence of phosphate transacetylase and β-ketothiolase is proportional to protein concentration with extracts of most tissues. However, studies with chicken liver extracts are complicated by the presence in these extracts of a factor which interferes with acetoacetate formation. This factor has been identified as an acid phosphohydrolase which hydrolyzes the phosphate monoester bond of coenzyme A, forming the inactive 3′-dephosphocoenzyme A. This enzyme has been purified 300-fold from chicken liver extracts, and some of its properties have been examined. The rate of inactivation of coenzyme A by the enzyme is neither enhanced by divalent cation nor inhibited by metal-binding agents. Enzymatic inactivation of coenzyme A is optimal at pH 3.6, with half-maximal rates observed at pH 5.5 and below pH 2.5. The most highly purified enzyme fraction exhibited phosphohydrolase activity against a wide variety of phosphate esters. Some evidence was obtained to suggest that the coenzyme A phosphohydrolase could be separated from nonspecific acid phosphohydrolase.
OXIDATION OF GLUCOSE-U-C14 AND PALMITATE-1-C14 BY LIVER, KIDNEY, AND DIAPHRAGM FROM HAMSTERS IN COLD EXPOSURE AND HIBERNATION
Authors: Baumber Joan , Denyes Arliss
Published: December 2009

The percentage of glucose-U-C14 and palmitate-1-C14 converted to C14O2 by tissue slices from golden hamsters exposed to cold, hibernating, and arousing from hibernation was studied. Liver, kidney, and diaphragm were the tissues selected. It was found that liver slices had an increased capacity to oxidize palmitate and a decreased capacity to oxidize glucose to CO2 throughout cold exposure, hibernation, and arousal. Kidney also had an increased oxidation of palmitate at 48 hours of cold exposure, but this declined on cold acclimation. During hibernation, in vitro conversion of both palmitate and glucose to CO2 was reduced. Conversion of palmitate and glucose to CO2 by diaphragm was depressed during hibernation. During arousal, oxidation of glucose by diaphragm was greater than that during hibernation, while oxidation of palmitate did not change. It was concluded that the results did not support a view that there is a preferential catabolization of lipid by all tissues in the cold-acclimated and hibernating hamster.
GLYCOPROTEINS AS COMPONENTS OF THE LETHAL FACTORS IN COBRA VENOM (NAJA NAJA)
Authors: Braganca Beatriz M. , Patel N. T.
Published: December 2009

A number of protein fractions (eight) have been separated from crude cobra venom (Naja naja) by agar electrophoresis on slides. A study of the lethal effect of the various fractions has demonstrated that there are two fractions which are lethal to mice when injected individually. The most potent of the lethal factors (MLD = 6 μg) contained a glycoprotein. Treatment of crude venom and the lethal fraction (eluted from the electrophoretic pattern) with periodate under mild conditions in which only the C—C linkages of the carbohydrates are believed to be oxidized resulted in about 50% loss of toxicity. These results suggest that the carbohydrate moiety of the glycoprotein is required for its lethal effect. Sialic acid has been detected in crude venom, but treatment of venom with the specific enzyme neuraminidase did not affect the toxicity of venom.
THE OXIDATION OF LEUCINE BY EHRLICH ASCITES CARCINOMA CELLS
Authors: Scholefield P. G.
Published: December 2009

The oxidation of leucine-1-14C to14CO2by Ehrlich ascites carcinoma cells was inhibited on addition of pyruvate and other α-keto acids, a maximum inhibitory effect being attained with 1 mM pyruvate. The only compound, among those tested, which reversed this inhibition was malonate. Oxidation of leucine-2-14C to14CO2occurred at a rate which was 1% of that observed with leucine-1-14C and was sensitive to the presence of fatty acids as well as to pyruvate. Glutamine was a particularly effective inhibitor of leucine oxidation. The inhibition produced by isoleucine was competitive, the KIvalue being 0.13 mM compared with the KMvalue of 0.2 mM. It is suggested that the inhibition by pyruvate is due to a competition between pyruvate and the α-ketoisovaleric acid derived from leucine for the cofactors required for the oxidation of the α-keto acids. In contrast, oxidation of leucine-1-14C by mouse liver slices was increased approximately threefold by pyruvate.
STUDIES ON BIOSYNTHETIC ENZYMES: I. MUTANT FORMS OF HISTIDINOL DEHYDROGENASE FROM NEUROSPORA CRASSA
Authors: Creaser E. H. , Bennett D. J. , Drysdale R. B.
Published: December 2009

Data are presented on the kinetic properties of the enzyme histidinol dehydrogenase obtained from the wild type Neurospora crassa and from 15 mutants. Differences were observed in pH curves and in Michaelis constants, both for histidinol and NAD. Ten mutants had modified affinity for NAD and three for histidinol, and one was modified in both these parameters. Two temperature-sensitive mutants were found to have an enzyme with a different activation energy from the normal. The data are discussed in relation to theories about whether histidinol dehydrogenase is a multifunctional enzyme in this organism or is part of an operon system.
THE EFFECTS OF INSULIN AND ADRENALIN ON THE METABOLISM OF GLUCOSE AND LACTATE BY PERFUSED GUINEA PIG HEARTS
Authors: Davis E. J.
Published: December 2009

The effects of insulin and adrenalin on the metabolism of14C-labelled glucose and lactate by perfused guinea pig hearts have been studied. In the absence of other exogenous substrates, adrenalin almost triples the amount of glucose oxidized to CO2, with a concomitant large increase in rates of glycolysis and glycogenolysis. Insulin has little or no effect on the rate of glucose oxidation, but greatly increases lactate accumulation, glycogen synthesis (from glucose), and amino acid labelling from14C-glucose.In hearts from starved animals, or in the presence of acetate, both insulin and adrenalin markedly increase the rate of glucose metabolism. When both insulin and adrenalin are present, both glucose and lactate compete favorably with acetate and endogenous substrates for oxidation.
PYRUVATE-2-14C METABOLISM IN SKIN
Authors: Booij H. Lorenz
Published: December 2009

The [Formula: see text] of the skin of young white rats was determined and the influence of pH, temperature, calcium, and different substrates studied. When pyruvate-2-14C was used as substrate radioactivity appeared in the respiratory CO2, acetoacetate, and the lipid and protein fractions of the skin. Addition of unlabelled pyruvate or Krebs cycle intermediates reduced the radioactivity of the respiratory CO2. Malonate added to the incubation medium had no effect on the radioactivity of the respiratory CO2, but resulted in a marked increase in the amount of radioactivity of acetoacetate C1.
REACTION OF FORMALDEHYDE AND THIOFORMALDEHYDE WITH MERCURIPAPAIN
Authors: Darlington W. A. , Keay L.
Published: December 2009

In a colorimetric assay with benzoyl-DL-arginine p-nitroanilide, acetylated and benzoylated papains retain full activity. Thus the ε-amino groups of the lysine residues are not required for enzyme activity. Intramolecular crosslinking of an enzyme could in theory stabilize secondary and tertiary structure and oppose denaturation. Thioformaldehyde is much more reactive with mercuripapain than formaldehyde, incorporating much more readily into the enzyme at equivalent concentrations. Incorporation is extensive, however, on reactive functional groups on the amino acid side chains, since acetylation decreased the incorporation markedly. In no case was there evidence of heat stabilization.
METABOLISM OF ORGANOPHOSPHORUS INSECTICIDES: III. FATE OF THE METHYL GROUPS OF DIPTEREX IN VIVO
Authors: Hassan A. , Zayed S. M. A. D.
Published: December 2009

Direct evidence for the hydrolysis of O-methyl ester linkage(s) of Dipterex in the rat has been obtained using Dipterex in which the two methyl groups are C14-labelled. Following a single injection (i.p.) of radio-Dipterex, about 60% of the C14activity was recovered, after 24 hours, in the expired air and in the urine. C14O2and C14-formate constituted about 50% of the recovered radioactivity. The contribution of P—OCH3cleavage to the detoxification of the insecticide has been discussed. A scheme for the fate of the methyl groups has been suggested.
PHOSPHODIESTERASE AND ACID PHOSPHATASE ACTIVITIES OF AVIAN BONE MARROW CELLS
Authors: Bristow Gerald Kingsley , Yamada Esther W.
Published: December 2009

Avian bone marrow has been found to contain a phosphodiesterase as well as an acid phosphatase. Some properties of these enzymes have been described. Because the phosphodiesterase of this tissue has an alkaline pH optimum, is activated by magnesium ions, and acts on the specific substrate p-nitrophenyl thymidine 5′-phosphate, it is probably a phosphodiesterase I such as is present in snake venom and other tissues.The intracellular distribution of these two enzymes in normal and regenerating bone marrow was studied. Subcellular fractions were prepared by differential centrifugation or by centrifugation through sucrose density gradients. The RNA and DNA content of each fraction was determined. By the methods used no differences in the properties or intracellular distribution of the two enzymes in normal and regenerating bone marrow were found.
THE INCORPORATION OF C14-LABELED PRECURSORS INTO THE DNA, RNA, AND PROTEINS OF L-CELL NUCLEI IN THE PRESENCE OF TRITIATED THYMIDINE
Authors: Krause Margarida O.
Published: December 2009

The effect of tritiated thymidine on the incorporation of C14-labeled thymidine, uridine, phenylalanine, and lysine into nuclei of exponentially growing L-cells was studied.The incorporation of each of the C14-labeled precursors was compared in the presence and absence of H3-thymidine. Results revealed a stimulation in the incorporation of C14-thymidine, C14-uridine, and C14-phenylalanine and a depression in the incorporation of C14-lysine in the presence of tritiated thymidine.
SYNTHESIS OF PHOSPHORIC ACID ESTERS OF α-METHYLCHOLINE, β-METHYLCHOLINE, AND HOMOCHOLINE
Authors: Baer Erich , Cooper Paul
Published: December 2009

The synthesis of the phosphoric acid esters of α-methylcholine, β-methylcholine, and homocholine is described. The esters were obtained by phosphorylating the iodides of α-methylcholine, β-methylcholine, and homocholine with diphenylphosphoryl chloride and pyridine, converting the iodides of the diphenylphosphoric acid esters of the respective cholines into the corresponding phosphates by consecutive treatment with silver carbonate and phosphoric acid, and removing the protective phenyl groups by catalytic hydrogenolysis. The rates of hydrolysis of the phosphoric acid esters of α- and β-methylcholine and homocholine in 2 N hydrochloric acid at 125° were determined.
POLYSACCHARIDES, NUCLEIC ACIDS, AND PROTEIN OF WHEAT STEM RUST (PUCCINIA GRAMINIS TRITICI) UREDIOSPORES
Authors: Klöker W. , Ledingham G. A. , Perlin A. S.
Published: December 2009

Some polymeric constituents of Puccinia graminis tritici urediospores are described. Prolonged extraction of the spores with hot water affords polysaccharide material containing D-mannose, D-galactose, and D-glucose. A levorotatory mannan, separated from this material by copper complexing, is shown to possess a highly ordered structure in which isolated β-1,4- and β-1,3-linked units alternate along the linear chain. The galactosyl units of the extracted polysaccharide are present in the furanosyl form. Acetolysis of the insoluble spore residues shows that pentoses and glucosamine are additional constituent sugars.Ribonucleic acids are isolated by extraction with phenol followed by ion-exchange chromatography, and similar material is obtained from the hot water extract. The phenol treatment also releases much of the spore protein, which is recovered in a highly purified condition. The composition of these polymeric urediospore constituents has been determined.
THE DISTRIBUTION AND ELIMINATION OF TRITIATED PORCINE CERULOPLASMIN IN THE RAT
Authors: Brown F. Christine , Mitchell Robert J.
Published: December 2009

Porcine ceruloplasmin was labeled with tritium by the Wilzbach procedure. After purification, the tritiated protein was injected intravenously into rats and the biological half-life, turnover rate, and other parameters were determined. Under these conditions, a half-life of 3.2 days was calculated for ceruloplasmin. The tritiated protein was lost from rat plasma at the same rate whether injected intravenously or intraperitoneally. After subcutaneous injection it was lost at twice the rate as after intravenous injection.The ratio of total exchangeable ceruloplasmin to plasma ceruloplasmin was calculated to be about 14, indicating a large extravascular pool. Radioactivity excreted in the urine was associated mostly with H2O and neutral salts.
PHOSPHOLIPIDS: II. A CORRELATION OF CHEMICAL STRUCTURE WITH THROMBOPLASTIC ACTIVITY
Authors: Grisdale P. J. , Okany A.
Published: December 2009

A series of synthetic phosphatidylserines containing saturated fatty ester residues (C6 to C18) has been synthesized. These compounds have been studied in combination with natural phosphatidylethanolamine in the two-stage thromboplastin-generation test. The observed activity of these mixtures depends on the fatty acid chain length of the phosphatidylserine. These variations are accounted for in terms of the micelle theory of thromboplastic activity.
PATHWAYS FOR THE METABOLISM OF GLYOXYLATE AND ACETATE IN GERMINATING FATTY SEEDS
Authors: Sinha S. K. , Cossins E. A.
Published: December 2009

Cotyledons of germinating sunflower, pumpkin, linseed, and watermelon seeds and the endosperm of germinating castor bean seeds have been examined for their ability to utilize glyoxylate-C14and acetate-C14for the biosynthesis of amino acids. All of the tissues examined readily utilized these acids when supplied in micromolar amounts to tissue slices. The chief products of this utilization included the organic acids of the glyoxylate and tricarboxylic acid cycles and a number of amino acids and amides. The results are interpreted as indicating that, in sunflower, watermelon, linseed, and pumpkin seeds, malate formed in the malate synthetase reaction is metabolized by the partial reactions of the tricarboxylic acid cycle. α-Ketoglutarate produced by these reactions is extensively utilized in the biosynthesis of glutamate, γ-aminobutyrate, and glutamine. In agreement with data already published, castor bean endosperm utilized acetate for the biosynthesis of sugars. This tissue also utilized glyoxylate for the formation of glycine, serine, glycollate, and malate. It is concluded that, with the exception of castor bean endosperm, acetyl CoA arising as a result of fatty acid oxidation might be utilized for amino acid biosynthesis via the partial reactions of the glyoxylate and tricarboxylic acid cycles.
ELECTROPHORETIC CHARACTERIZATION OF HUMAN DEHYDROGENASES
Authors: Katz A. M. , Kalow W.
Published: December 2009

Several isoenzymes of lactate, malate, and isocitrate dehydrogenases have been demonstrated in human skeletal muscle, heart, and liver. Single zones of activity were shown for glucose-6-phosphate and glutamate dehydrogenases. A zone possessing a marked reducing capacity towards nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate was visualized in the absence of any substrate, using the tetrazolium-coupled histochemical method. This zone represents the so-called "nothing dehydrogenase".
ENHANCEMENT OF RIBONUGLEOSIDE SYNTHESIS IN EHRLICH ASCITES TUMOR CELLS BY ARSENATE AND IODOACETATE
Authors: Paterson A. R. P. , Simpson A. I.
Published: December 2009

Ehrlich ascites tumor ceils in vitro synthesize ribonucleosides, which appear mainly in the incubation medium, by the transfer of ribose from a donor ribonucleoside to an acceptor base. In the present study, it was found that the rates of synthesis of inosine and uridine in this system were markedly enhanced in the presence of arsenate or iodoacetate. The exchange of isotope between extracellular inosine and hypoxanthine-8-C14was similarly enhanced by arsenate, but the more rapid exchange between uridine and uracil-2-C14was unaffected. Arsenate did not cause changes in the rates of uridine breakdown that would account for the enhanced rate of nucleoside synthesis and did not promote the release of nucleoside-synthesizing enzymes from the tumor cells into the incubation medium. Because lactate formation during the uridine-supported synthesis of inosine was markedly inhibited by arsenate and iodoacetate, the increase in ribonucleoside synthesis appears to be indirect and to be related to inhibition of ribose phosphate catabolism.
GLYCOLYSIS IN NORMAL AND NEPHROTIC RAT KIDNEY
Authors: Nicholls D. M.
Published: December 2009

Experimental nephrosis was induced in rats by administering the aminonucleo side of puromycin, which inhibits protein synthesis in cell-free and whole-cell preparations.Slices of renal cortex from nephrotic rats incubated for 2 hours in Krebs–Ringer phosphate buffer with glucose as substrate accumulated two to three times more lactate and pyruvate than did slices from normal rats under aerobic but not under anaerobic conditions. Nephrotic cortex metabolizing endogenous substrate similarly accumulated three times as much pyruvate as normal cortex, but no accumulation of lactate occurred in either normal or nephrotic cortex in the absence of glucose. These changes were not observed in nephrotic medulla, nor were they accompanied by any change in oxygen consumption, glucose uptake, or glutamic–pyruvic transaminase activity. Decreased dry weight of the nephrotic slices was accompanied by a similar small decrease in their protein content. It is postulated that there is a decreased activity of enzymes metabolizing pyruvate in the cortex of aminonucleoside-treated rats.
A RIBONUCLEIC ACID FRACTION OF NEUROSPORA CRASSA EVOKING DEVELOPMENT OF A PSEUDO-TRYPTOPHAN SYNTHETASE ACTIVITY BY EXTRACTS OF MUTANTS TD1, TD2, AND TD3
Authors: Wainwright S. D. , McFarlane E. Sandra
Published: December 2009

"Soluble RNA" fractions isolated from the wild-type strain of Neurospora crassa evoked development of a pseudo-tryptophan synthetase enzyme activity in vitro by extracts of mutant strains lacking ability to produce the enzymic activity. The RNA fractions contained no detectable "template RNA". Some properties of the component eliciting development of pseudo-tryptophan synthetase activity are reported.
THE MUCOPOLYSACCHARIDES OF AVIAN OVIDUCT, EGG, SKIN, AND COMB, AND OF PORCINE SKIN
Authors: Wood D. F. , Anastassiadis P. A.
Published: December 2009

Samples of the following tissues were hydrolyzed by pepsin and by trypsin: magnum, isthmus, shell glands, and vagina of avian oviduct; avian and porcine skins; avian egg; avian comb. Unhydrolyzed mucopolysaccharides were precipitated by ethanol, purified, and then fractionated by increasing concentrations of ethanol. The purity of the enzymic preparation influenced the yields and degree of purification of the mucopolysaccharide fractions but scarcely affected the composition of the mucopolysaccharides in the fractions. In general, mucopolysaccharides from skins, comb, and shell glands had relatively low ratios of sugars to hexuronic acid whereas those from magnum, isthmus, and egg had relatively high ratios. The higher the hexuronic acid content of a mucopolysaccharide, the higher was the yield of mucopolysaccharide. Fractions precipitated by lower ethanol concentrations had lower ratios of sugars to hexuronic acid than those precipitated at higher ethanol concentrations.
LYTIC ENZYMES OF SORANGIUM SP.: A COMPARISON OF SOME PHYSICAL PROPERTIES OF THE α- AND β-LYTIC PROTEASES
Authors: Jurášek L. , Whitaker D. R.
Published: December 2009

Ultraviolet absorption spectra of the two enzymes were determined. The β-enzyme has the lower λmax and the higher absorptivity between 260 and 300 mμ. The spectra in 0.1 N alkali – 8 M urea indicated that the β-enzyme has a substantially higher ratio of tyrosine to tryptophan residues and a substantially higher content of both amino acids.Electrophoresis in starch gel at pH 8 and in cellulose acetate at pH's from 3 to 9 showed no evidence of heterogeneity in the enzyme preparations, but the electrophoretic pattern of the β-enzyme in acetate – 7 M urea buffer depends on the period of preexposure of enzyme to the buffer; brief or prolonged (24 hours) periods give patterns with one component, intermediate periods can give patterns with two components. In all buffers tested, the mobility of the α-enzyme was slightly greater than that of lysozyme; in all buffers except those containing phosphate, the mobility of the β-enzyme was slightly less than that of lysozyme.The molecular weight of both enzymes was estimated to be 19,000 by the Archibald method; the estimate for the β-enzyme assumes a partial specific volume of 0.72. The elution volume/void volume ratios of the enzymes were compared in Sephadex G75. The ratio for the α-enzyme was consistent with a molecular weight of approximately 19,000. The ratio for the β-enzyme was anomalously high; the enzyme is probably weakly adsorbed on the gel. Neither enzyme showed any indication of heterogeneity on displacement from hydroxylapatite.
EFFECTS OF PHENFORMIN AND HYPOGLYCIN ON GLUCONEOGENESIS OF RAT TISSUES
Authors: Patrick S. J.
Published: December 2009

The hypoglycemic agents hypoglycin A and phenformin lower the ATP levels of slices of rat kidney and liver in vitro. These agents, as well as dinitrophenol, interfere with glucose production by kidney and liver slices in the presence of pyruvate or of various intermediate compounds of glycolysis. There is evidence that the activities of fructose-1,6-diphosphatase and glucose-6-phosphatase may be indirectly affected by these agents.
QUANTITATIVE PRECIPITATION OF VARIOUS 3β-HYDROXYSTEROLS WITH DIGITONIN
Authors: Haust H. L. , Kuksis A. , Beveridge J. M. R.
Published: December 2009

Conditions are described for the quantitative precipitation of nine 3β-hydroxysterols with digitonin. After removal of excess reagent, the sterol and digitonin moieties are dissolved in a known volume of dry pyridine. An aliquot of the pyridine solution is processed to give a measure of total 3β-hydroxysterol by estimating the digitonin moiety with the use of anthrone. From another aliquot, the free sterols may be regenerated for differential-photometric and gas–liquid or thin-layer chromatographic analysis.Recoveries for each sterol at three levels of concentration were as follows: β-sitosterol, 98.6 ± 1.8% (mean and S.D.); campesterol, 99.1 ± 1.9%; stigmasterol, 98.9 ± 1.7%; stigmastanol, 99.1 ± 1.9%; cholesterol, 100.1 ± 1.5%; cholestanol, 100.8 ± 1.3%; coprostanol, 93.6 ± 1.6%; Δ7-cholestenol, 98.5 ± 1.8%; and 7-dehydrocholesterol, 91.9 ± 1.8%.
AN ENZYMATIC EVALUATION OF THIOL RADIOPROTECTORS
Authors: Scaife J. F.
Published: December 2009

A number of thiol and disulfide compounds have been tested for their ability to inhibit the oxidation of α-ketoglutarate by rat-liver homogenates. In general, a correlation exists between the degree of inhibition and the radioprotective ability of the compound. It is possible that a better correlation exists for the corresponding disulfides.The inhibition involves oxidation of the thiol, and the disulfides were found to be more potent inhibitors than the thiols.There is no change in the ATP level of normal tissues after the administration of aminoethylisothiouronium bromide hydrobromide in vivo, and the protective ability of this compound is not considered to be related to any interference with mitochondrial oxidative phosphorylation. Mitochondrial respiration is, however, inhibited. The results support the mixed disulfide protection theory of Eldjarn and Pihl, and provide a physiologically significant test system for this hypothesis.
PARTICIPATION OF THE GLYOXYLATE CYCLE IN THE METABOLISM OF ETHANOL BY CASTOR BEAN ENDOSPERM TISSUES
Authors: Peterson Carol A. , Cossins E. A.
Published: December 2009

The kinetics and pathway of ethanol metabolism in endosperm tissues of the germinating castor bean-have been studied by incubating tissue slices with micromolar quantities of ethanol-1-14C and ethanol-2-14C. In short term experiments, ethanol-14C was incorporated into the organic acids and acidic amino acids. When the experimental period was increased up to 1 hour, large amounts of ethanol-2-14C were incorporated into the sugars, and ethanol-1-14C was extensively incorporated into the respiratory carbon dioxide. Incorporation of ethanol-14C was stimulated by incubation of the tissues with glyoxylate. Ethanol metabolism was markedly inhibited by iodoacetate and malonate. These inhibitors also changed the distribution of14C in the products isolated. Isotopic competition studies indicated that ethanol was incorporated into the acids of the glyoxylate and the tricarboxylic acid cycles at rates substantially lower than acetate.The results are interpreted as being consistent with a metabolism of ethanol mainly via the glyoxylate cycle with some cycling of ethanol carbon through the tricarboxylic acid cycle.
ENOLASE ACTIVITY IN MARINE PLANKTONIC ALGAE
Authors: Antia N. J. , Kalmakoff J. , Watt A.
Published: December 2009

Evidence was obtained for enolase activity in cell-free extracts of 12 species of marine planktonic algae belonging to the classes Bacillariophyceae, Chlorophyceae, Chrysophyceae, Cryptophyceae, and Myxophyceae. By the test methods used, no activity could be detected in a coccolithophorid and a dinoflagellate.
BIOSYNTHESIS OF LIPIDS IN PLANTS: II. INCORPORATION OF GLYCEROPHOSPHATE-32P INTO PHOSPHATIDES BY CELL-FREE PREPARATIONS FROM SPINACH LEAVES
Authors: Sastry P. S. , Kates M.
Published: December 2009

Cell-free homogenates of spinach leaves incorporated glycerophosphate-32P into phosphatides when supplied with adenosine triphosphate, Mg++and coenzyme A (CoA). Most of the activity of the homogenate was associated with the microsome fraction sedimented at 104,000 × g, but some activity was also present in the chloroplast fraction. In all systems, most of the32P incorporated appeared in phosphatide acid (+ lysophosphatidic acid), with small to trace amounts in phosphatidyl glycerol and phosphatidyl inositol. Coenzyme A and adenosine triphosphate + Mg++were obligatory cofactors for the incorporation of α-glycerophosphate-32P but acetate + bicarbonate, cytidine triphosphate, or light were not essential. The results demonstrate the presence of acyl-CoA:L-glycerol-3-phosphate O-acyltransferase in the microsome fraction of spinach leaves and also indicate the existence of enzyme systems catalyzing the conversion of phosphatidic acid to phosphatidyl inositol and phosphatidyl glycerol.
TISSUE LACTIC DEHYDROGENASE ISOZYMES DEVELOPMENTAL PATTERNS IN THE NEONATAL RAT
Authors: Blatt William F. , Blatteis Clark M. , Mager Milton
Published: December 2009

The isozyme forms of lactic dehydrogenase (LDH) were studied in excised rat tissues up to 45 days after birth. The predominant subtype at birth was the muscle form, reflecting anaerobic glycolysis. Development was characterized by an increase in the relative ratio of heart (H) to muscle (M) in all tissues studied; however, the major form in liver and muscle was quite clearly the M type. Emergence of the typical adult LDH distribution would appear to be complete in 2–3 weeks after birth, but the adult levels of total LDH activity were not attained during the 45 postnatal days of this study.
REGULATION OF ACETOHYDROXY ACID SYNTHETASE IN STREPTOMYCIN-DEPENDENT ESCHERICHIA COLI
Authors: Polglase W. J.
Published: December 2009

The formation of acetolactate from pyruvate by extracts of streptomycin-dependent Escherichia coli was inhibited, competitively, by L-valine, thus establishing the potential in the dependent mutant for regulation of the activity of acetohydroxy acid synthetase through end-product inhibition. Furthermore, the level of acetohydroxy acid synthetase was decreased in streptomycin-dependent E. coli by growth in minimal medium to which had been added the end products of the biosynthetic pathways initiated by this enzyme, thus establishing the potential in dependent cells for regulation of acetohydroxy acid synthetase through repression. In contrast, the specific activity of acetohydroxy acid synthetase in extracts of streptomycin-dependent E. coli increased in proportion to the concentration of antibiotic (dihydrostreptomycin) present in the medium during growth, thereby indicating a positive regulatory effect of dihydrostreptomycin on the formation of this enzyme. The formation of two enzymes used as monitors, glucokinase, and glutamic dehydrogenase, was not affected by variation in antibiotic concentration.
ACETYL ESTERASE IN BACILLUS CEREUS SPORES
Authors: Roberts Thomas L. , Rosenkrantz Harris
Published: December 2009

The paucity of data on esterase activity in intact, dormant spores encouraged further examination of Bacillus cereus spores with more sensitive fluorescent methods. Esterase activities of intact and ballistically ruptured spore preparations against α-naphtyl acetate and fluorescein diacetate in phosphate and carbonate buffers were compared. Enzyme inhibition with toluene and molybdate was also inspected. It was found that intact spores and the supernatant from ruptured spores readily hydrolyzed both acetate substrates. Toluene caused approximately an 80% inhibition, whereas that with molybdate was complete. It was suggested that esterase activity in bacterial spores varies with species.
LIPASE AND ACETYL ESTERASE ACTIVITIES IN INTACT BACILLUS COAGULANS SPORES
Authors: Roberts Thomas L. , Rosenkrantz Harris
Published: December 2009

Since data on esterase content of intact dormant spores are meager, a study was carried out with various enzyme substrates and several methods of product detection on intact and ruptured preparations of Bacillus coagulans. Measurement of hydrolysis of triacetin, naphthyl acetates, fluorescein diacetate, ethyl acetate, and ethyl butyrate demonstrated the presence of arylesterase, carboxylesterase, acetyl esterase, and lipase activities in both the intact and ruptured preparations of the non-germinated organism used. It was observed that spore esterase was inhibited by normal and basic copper acetate, eserine, taurocholate, 253.7 mμ ultraviolet light, and temperatures between 50 and 100 °C.
COMPARISON OF ELASTINS FROM VARIOUS SOURCES
Authors: Anwar Rashid A.
Published: December 2009

Elastin preparations from bovine ligamentum nuchae, human aorta, and rabbit ear were compared. All three preparations were found to contain desmosine and isodesmosine. It is proposed that the presence of desmosine and isodesmosine be taken as diagnostic of elastin, as hydroxyproline is for collagen. The procedures for the isolation and qualitative determination of desmosine and isodesmosine are described. Some of the problems in obtaining 'pure elastins' are pointed out.
THE LIPIDS IN NORMAL CHICKEN LIVER
Authors: Sgoutas Demetrios
Published: December 2009

The livers of male chicks which had been fed a soybean and corn type ration for 8 weeks were exhaustively extracted with chloroform–methanol. The total (4.47%) lipid extract was separated into neutral and phospholipid fractions on a Unisil column and the mixed fatty acids in each fraction determined with the aid of gas chromatography. The neutral lipid fraction contained 3.16% hydrocarbons, 4.73% cholesterol esters, 74.99% triglycerides, 0.28% free fatty acids, 11.57% cholesterol, 3.37% diglycerides, and 1.54% monoglycerides. The phospholipid fraction contained 5.7% cardiolipin, 32.3% phosphatidyl ethanolamine, 7.3% phosphatidyl inositol, 3.0% phosphatidyl serine, 47.9% phosphatidyl choline, and 3.8% sphingomyelin and lysophosphatidyl choline. The cholesterol ester and diglyceride fractions contained twice as much linoleic acid as the other neutral lipid fractions. Phospholipids were characterized by a high content of polyunsaturated fatty acids.
THE EFFECT OF INSULIN AND DIABETES ON GLUCOSE METABOLISM IN HUMAN SKIN
Authors: Kahlenberg A. , Kalant N.
Published: December 2009

The in vitro effects of insulin on glucose transport and dissimilation were studied in human skin. Slices of skin obtained post-mortem were incubated in phosphate and bicarbonate media with a glucose concentration of 5.6 mM. In both buffers, insulin increased the glucose uptake in non-diabetic skin without affecting the intracellular glucose content. Similar results were obtained for diabetic skin incubated in a phosphate buffer.In bicarbonate buffer, the basal rate of glucose utilization of skin from diabetics was lower than normal; this may have been the result of a defect in the phosphofructokinase reaction. Diabetic skin also had an increased responsiveness to insulin in bicarbonate buffer.Non-diabetic skin incubated in phosphate buffer had a lower basal rate of glucose uptake and a greater responsiveness to insulin than the same tissue incubated in bicarbonate buffer.It is concluded that (a) skin from diabetic humans incubated in bicarbonate buffer had a decreased basal rate of glucose utilization and increased responsiveness to insulin; (b) insulin stimulated both glucose transport and dissimilation in diabetic and non-diabetic human skin.
INCORPORATION OF14C INTO TWO PROTEINS FROM RAPESEED (BRASSICA NAPUS L.)
Authors: Finlayson A. J.
Published: December 2009

Four groups of five rapeseed plants (Brassica napus L.) were injected with sodium acetate-2-14C at intervals between flowering and maturity. Two14C-labeled proteins were isolated from a water extract of the oil-free seed meal. The specific activities of the two proteins and of some amino acids isolated from them suggested rate differences in protein synthesis, or, alternatively, conversion of one protein into another. The results also showed that synthesis of these proteins occurs over a considerable period in the plant's development.
THE RATE OF FORMATION OF C-21 STEROID SULFATES FROM 4-14C-PROGESTERONE BY HUMAN NEWBORN ADRENAL SLICES
Authors: Klein G. P. , Giroud C. J. P.
Published: December 2009

Adrenal slices obtained from a premature infant were incubated in the presence of ATP and of 4-14C-progesterone. The incorporation of this precursor into seven corticosteroids was studied as a function of the time of incubation. Radiochemical purity of the products was assessed by double isotope derivative assay. The results demonstrated the rapid synthesis of 11-deoxycarticosterone sulfate and of corticosterone and 11-deoxycortisol, followed by the slow disappearance of the latter two steroids and the progressive formation of their respective C-21 ester sulfates. The predominant reactions observed were 21-hydroxylation of progesterone followed by extensive sulfo-conjugation of the product.
CHANGES IN THE AMINO ACID CONTENT OF THE FIRST THREE LEAVES OF RIDEAU WHEAT FOLLOWING VERNALIZATION
Authors: Weinberger Pearl , Godin C.
Published: December 2009

The aftereffect of chilling winter wheat, Triticum aestivum (var. Rideau), after a period of imbibition, was studied by making a periodic partial analysis of the metabolism of some nitrogen compounds in the first three emergent leaves throughout their growth period. Total protein nitrogen measurements indicated that prior chilling (vernalization) accelerated some stages of leaf development.The composition of the alcohol-soluble amino acid fraction varied with leaf ontogeny in both control and vernalized plants. The most pronounced effect of vernalization was to depress the relative content of arginine, which was one of the major constituents of the soluble amino acid fraction in leaves from untreated seed. The concentrations of other important amino acids, γ-aminobutyric acid, glutamic acid, and the amine, glutamine, varied with the physiological age of the leaf, and vernalization did not alter this relationship.
THE HYDROLYSIS OF PHENYLALANINE METHYL ESTER BY BOVINE THROMBIN
Authors: Cole Edmond R. , Koppel J. L. , Olwin John H.
Published: December 2009

Thrombin, usually regarded as a trypsin-like enzyme capable of hydrolyzing only esters of the amino acids arginine and lysine, was found to hydrolyze certain other amino acid esters which are considered specific chymotrypsin substrates. L-Phenylalanine methyl ester inhibited the activation of purified bovine prothrombin by autoprothrombin C, Ac-globulin, phospholipid, and calcium. It was subsequently shown that thrombin is capable of hydrolyzing L-phenylalanine methyl ester or L-tyrosine ethyl ester. This activity developed simultaneously with fibrogen clotting activity during activation of purified bovine prothrombin in 25% sodium citrate solutions. Moreover, the activity was closely associated with clotting activity on subsequent chromatography on DEAE-cellulose and Amberlite IRC-50 resin columns. All preparations of bovine thrombin, representing a wide range of purity, which have been examined, exhibited this hydrolyzing activity toward L-phenylalanine methyl ester. Further evidence linking this esterase activity with fibrinogen clotting activity was obtained when both activities were inhibited by 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate, an inhibitor of chymotrypsin.
THE SYNTHESIS OF CHOLESTEROL GLUCOPYRANOSIDURONATE
Authors: Nagayama Fumio , Saito Akira , Idler D. R.
Published: December 2009

Cholesterol glucopyranosiduronate was synthesized by the hydrolysis of cholesterol methyl triacetyl glucopyranosiduronate with barium hydroxide under mild conditions. Some of its properties were investigated.
AMINO ACID METABOLISM OF DIFFERENT MAMMALIAN CELL LINES
Authors: Chung R. A. , Brown R. W. , Beacham L. H. , Huang I-Lo
Published: December 2009

After long-term storage under liquid nitrogen, 16 different mammalian cell lines from normal and malignant origins were cultured in the presence of14C-glucose for 3 and 7 days without a change in growth medium.All cell lines synthesized from glucose at least six amino acids: aspartate, glutamate, serine, alanine, glycine, and threonine. In addition, HeLa S, human heart (HH), and L-929 synthesized cystine after 7 days of incubation without change of growth medium. The most highly labeled compounds were alanine, glycine, and glutamic acid in all cell media. The incorporation of14C into aspartic acid, serine, and threonine was for the most part detected in small amounts.Citrulline appeared in large quantities in the growth medium of HeLa F, HeLa Q, and HeLa Clone S-3, whereas arginine was greatly reduced after the 3-day growth period. At the same time, the ammonia content greatly increased in all three cases. Proline disappeared in the medium of HeLa S, HEp II, human amnion (HA-FL), canine kidney (MD-CK), human appendix (HA-A1), human liver (HL-CW), and human embryonic adrenal (W-AD62). Glutamic acid increased in the medium of monkey kidney (MK-MS) and canine kidney (MD-CK). In the HeLa Clone S-3 medium, lysine decreased and histidine increased.Each cell line in this investigation may be distinguished on the basis of the degree of14C incorporation into glutamic acid, serine, glycine, and alanine, except three pairs of cell lines: HEp II and HA-A1, MD-CK and MK-MS, and rat embryo and HeLa F.