bluuebunny/crossref_metadata_2025 huggingface dataset:
THE OXIDATION OF ETHANOLAMINE BY PLANT TISSUE PREPARATIONS
Authors: Richardson K. E. , Miedema E. , Vandor S. L.
Published: December 2009

Ethanolamine-1,2-14C was oxidized to14CO2by tissue slices from carrots, onions, beets, turnips, parsnips, radishes, pea seedlings, wheat seedlings, corn seedlings, and oat seedlings. A monoamine oxidase from spinach, beet, and bean leaves which catalyzed the oxidation of ethanolamine to glycolaldehyde was partially characterized. The enzyme catalyzed the oxidation of alkylmonoamines and arylalkylmonoamines but not diamines or N-substituted monoamines, which distinguishes it from previously reported plant amine oxidases.
THE EFFECTIVENESS OF EXOGENOUS GUINEA PIG INSULIN IN THE OX INSULIN IMMUNE GUINEA PIG
Authors: Aprile M. A. , Tirpak A. E. , Moloney P. J.
Published: December 2009

Insulin extracted from the pancreas of the guinea pig lowered the blood sugar level of ox insulin immune guinea pigs by an amount similar to that observed in non-immune guinea pigs, whereas the same dose of ox insulin or even double the dose did not lower the blood sugar level of immune guinea pigs. These results are consistent with previously reported findings, namely, that guinea pig insulin is not neutralized in vitro by guinea pig or horse anti-ox insulin sera, as shown by whole mouse test or mouse diaphragm test. By contrast, both codfish and sulfated insulins, which, relative to ox insulin are non-neutralizable by these antisera, are much less effective in the insulin-immune guinea pig than is guinea pig insulin.
CONSTITUENTS OF THE HEMOLYMPH OF THE LOBSTER, HOMARUS AMERIGANUS MILNE EDWARDS
Authors: Stewart James E. , Dingle J. R. , Odense P. H.
Published: December 2009

Electrophoretic and sedimentation analyses were made on the plasma and serum of the hemolymph of the lobster Homarus americanus, and on purified hemocyanin and fibrinogen prepared from these. Amino acid analyses of these two proteins and the plasma, and of the free amino acids of the plasma were also determined. Fibrinogen maintained its function and character upon isolation. It was completely and selectively removed from the plasma by stirring with small amounts of oleic acid. The pH of the hemolymph was 7.6; this was a stable characteristic. The lactic acid in the hemolymph of lobsters held unfed in a disturbing environment at first increased fivefold and then returned to normal; the carbohydrate level remained unchanged.
METABOLISM OF AMINO ACIDS IN AGROBACTERIUM TUMEFACIENS: I. UPTAKE OF L-VALINE BY RESTING CELLS
Authors: Behki R. M. , Hochster R. M.
Published: December 2009

The characteristics of14C-valine uptake by Agrobacterium tumefaciens are described. Highly significant differences were observed with the non-tumorogenic strain IIBNV6and the tumorogenic strain IIBV7K.Resting cells of strain IIBNV6displayed an amino acid uptake pattern, energy requirement, pool saturation, and substrate specificity typical of bacteria (e.g. Escherichia colt) which have been studied previously. In contrast, cells of the strain IIBV7K exhibited an apparent independence from external energy requirements and showed a non-specific competition by structurally unrelated amino acids for14C-valine uptake.In cells of this tumorogenic strain,14C-valine was metabolized after its uptake from the medium, and the metabolic product was effluxed into the extracellular fluid. This product was identified as α-ketoisovaleric acid. Cells of the strain IIBV7K were unable to accumulate this keto acid, although IIBNV6cells took it up readily.Valine uptake by IIBV7K cells was inhibited by a host of structurally unrelated amino acids, which were able to displace the accumulated valine from these cells.The deamination of valine to α-ketoisovaleric acid appears to be associated with a transaminase-type reaction in cells of the strain IIBV7K. Hydroxylamine inhibited the efflux of the product in this strain, whereas in the non-tumorogenic strain it inhibited14C-valine uptake.
CONTROL OF REDUCED NICOTINAMIDE-ADENINE DINUCLEO-TIDE OXIDATION BY PIGEON-HEART MITOCHONDRIA
Authors: Blanchaer M. C. , Griffith Thomas J.
Published: December 2009

The rate of oxidation of 10–35 μM reduced nicotinamide–adenine dinucleotide (NADH) by pigeon-heart mitochondria was increased not only by osmotic swelling and sonic disruption of the organelles but also by milder procedures such as washing or dilution, which had no deleterious effect on the P: O and respiratory control ratios when glutamate was the substrate. In all cases, the enhanced oxidation of 10 μM NADH was suppressed by 5 mM adenosine triphosphate (ATP). From these and other findings it was concluded that the access of extra-mitochondrial NADH to the respiratory chain is controlled at a minimum of two sites. Control of NADH flux through the first site is lost after treatment of the mitochondria by procedures which increase their permeability. A second level of NADH control survives sonic disruption of the mitochondria and is a site at which the oxidation of 10 μM NADH is stimulated by Piand inhibited by ATP, adenosine diphosphate (ADP), and oxidized nicotinamide–adenine dinucleotide (NAD+). The ATP and ADP effects at this level are not blocked by oligomycin. Magnesium releases the adenine nucleotide inhibition of NADH oxidation under certain conditions, but its site and mode of action is not clear as yet. In these experiments, NADH oxidation was determined polarographically and photometrically at 28° in a medium containing 0.23 M mannitol, 0.07 M sucrose, 0.02 M Tris–chloride, and 0.02 mM ethylenediamine tetra-acetic acid (EDTA) at pH 7.2.
FATTY ACIDS OF BRAIN IN HYPERVITAMINOSIS A IN RATS
Authors: Misra U. K.
Published: December 2009

The effect of administration of retinol (100,000 I.U. daily for 10 days) on the fatty acid composition of brain in rats has been studied. The administration of large doses of retinol to rats did not significantly affect the saturated fatty acids of brain, i.e. C 16:0, C 18:0, C 20:0, C 21:0, C 23:0, and C 24:0 as compared with untreated control. A significant increase in the concentration of brain oleic acid was found in hypervitaminotic A rats (27.9 ± 1.74%) as compared with the untreated controls (22.0 ± 2.70%). The concentrations of polyunsaturated fatty acids, i.e. C 20:4 and 22:6 were significantly reduced in hypervitaminotic A rats as compared with untreated controls.
LIPID BIOSYNTHESIS IN THE BOLL WEEVIL: FORMATION OF THE ACETATE PRECURSOR FOR LIPID SYNTHESIS FROM GLUCOSE AND RELATED CARBOHYDRATES
Authors: Lambremont Edward N. , Bennett Andrea F.
Published: December 2009

Glucose, sucrose, fructose, and their related glycolytic products, pyruvate and acetate, were readily converted into long-chain fatty acids by larval and adult boll weevils (Anthonomus grandis Boheman, Coleoptera:Curculionidae). By comparison of the radiorespirometric formation of14CO2of adults injected with differentially labeled glucose and pyruvate to the specific activity of lipid synthesized from these substrates, it was determined that glycolysis is the principal pathway by which acetate is produced. The patterns suggested that the boll weevil possesses the pentose phosphate pathway, which also accounts for a significant oxidation of glucose. Recombinations of labeled carbon atoms within and between intermediates of the pentose cycle allow synthesis of labeled fatty acid to take place with those carbons of glucose which could not ordinarily enter fat synthesis by glycolysis alone.
BIOSYNTHESIS OF MUSTARD OIL GLUCOSIDES: VII. FORMATION OF SINIGRIN IN HORSERADISH FROM HOMOMETHIONINE-2-14C AND HOMOSERINE-2-14C
Authors: Chisholm M. D. , Wetter L. R.
Published: December 2009

Five 14C-labeled amino acids were administered to horseradish (Armoracia lapathifolia Gilib.) leaves. Three of the amino acids, DL-homoserine-2-14C, DL-methionine-2-14C, and DL-homomethionine-2-14C (2-amino-5-(methylthio)-valeric acid), were precursors of the aglycone (allyl isothiocyanate) of sinigrin. The other two, DL-allylglycine-2-14C (2-amino-4-pentenoic acid) and DL-2-amino-5-hydroxyvaleric acid-2-14C, were incorporated in insignificant amounts. The relationships of the three efficient precursors are discussed. The syntheses of four 14C-labeled amino acids used in this investigation are described.
THE CHARACTERISTIC ALKALI-STABLE DINUCLEOTIDE SEQUENCES IN EAGH OF THE 16S AND 23S COMPONENTS OF RIBOSOMAL RIBONUCLEATES FROM ESCHERICHIA COLI
Authors: Nichols J. L. , Lane B. G.
Published: December 2009

Evidence is presented to show that the 23S component of Escherichia coli ribosomal RNA contains three principal alkali-stable dinucleotide sequences, GxpGp, CxpCp, and UxpGp, whereas the 16S component contains one major alkali-stable dinucleotide sequence which has been tentatively identified as N4MeCxpCp.
THE MEASUREMENT OF HUMAN THYROXINE-BINDING PROTEINS BY ELECTROPHORESIS ON CELLULOSE ACETATE MEMBRANES: STUDIES ON A SPURIOUS FOURTH THYROXINE-BINDING COMPONENT
Authors: Launay Marc P.
Published: December 2009

Electrophoresis of human serum enriched with 131I-labeled L-thyroxine was performed on strips of cellulose acetate in a tris(hydroxymethyl)aminomethane –ethylenediaminetetraacetate – borate buffer, pH 9.0. High-sensitivity scanning of the strips revealed the presence of a poorly defined radioactive component between α2- and γ-globulins. This component was present in all sera in which the affinity of thyroxine-binding prealbumin (TBPA) was less than 30%, and was inversely related to TBPA at thyroxine levels of 0.02,1.0, and 5.0 μg/ml. The α2γ component, like the other three thyroxine-carrying proteins, was found to vary considerably with the volume of serum applied to the strip. With increasing sample volumes, the percentage of radioactivity in the α2γ component decreased but the absolute amount remained constant. Furthermore, the α2γ component contained increasing proportions of the total radioactivity as larger amounts of stable L-thyroxine were added to the serum. Soaking the strips in buffer containing 0.06% bovine albumin before the samples were applied virtually eliminated the α2γ component and substantially increased TBPA. It was concluded that the α2γ component was due to trailing of TBPA across albumin and thyroxine-binding globulin, and that all the electrophoretic data obtained with media where some radioactivity cathodal to thyroxine-binding globulin was present should be cautiously reappraised.
THE BINDING OF131IODIDE BY CELL-FREE THYROID HOMOGENATES MEASURED BY EQUILIBRIUM DIALYSIS
Authors: Fawcett David M.
Published: December 2009

By use of equilibrium dialysis, thyroid homogenates, initially activated by dialysis against chlorinated water, were shown to bind131I. Part of the bound131I behaved as stable iodoprotein. The remainder, between 15 and 55% of the total, could be removed from the protein by dialysis against running water, or by protein precipitation with trichloroacetic acid. Both types of131I binding were inhibited by thiourea and thiocyanate. Perchlorate had no effect upon iodination but partially inhibited the reversible type of iodine binding over a narrow range of concentrations.Activated thyroid homogenates supplemented with iodide exhibited absorption properties at 355 mμ characteristic of sulfenyl iodide formation. Exposure of the thyroidal protein to chlorine during initial dialysis apparently resulted in the formation of a protein sulfenyl chloride, which, when reacted with131I-iodide, produced a mixture of protein sulfenyl131I-iodide and stable131I-iodoprotein.Nonthyroidal proteins containing sulfhydryl groups also were activated by dialysis against chlorinated water. Incubation of the activated nonthyroidal proteins with131I-iodide led to131I-iodoprotein formation. Sulfenyl iodides could be demonstrated in the nonthyroidal systems by spectrophotometric measurements, but these were less stable than the corresponding thyroid species. It is concluded that sulfenyl iodides may act as intermediates during protein iodinations in vitro.
EFFECT OF THIOL-MASKING AGENTS ON THE STROMATA OF RAT ERYTHROCYTES
Authors: Bide R. W. , Myers D. K.
Published: December 2009

The thiols of the stromata of rat erythrocytes were studied in relation to the K+loss and hemolysis caused by thiol-masking agents. When stromata were isolated from erythrocytes that had been incubated with radioactive thiol-masking agents, the total number of reactive thiols in the stromata was estimated to be 0.03 μmole/109cells, or 2% of the reactive thiols in the whole cell. A fast-reacting and a slow-reacting group of stromal thiols, constituting approximately 14 and 86% respectively of the total, could be distinguished by titration with p-chloromercuribenzoate (pCMB). The K+loss and hemolysis caused by pCMB, and presumably by other thiol-masking agents, appeared to be related to inhibition of the fast-reacting group of stromal thiols. Inhibition of these thiols also facilitated removal of residual hemoglobin and other loosely associated proteins from the erythrocyte membranes in the stromal preparations, without causing a disintegration of the stromata. The above effects may all reflect a disorganization of the stromal structure that resulted from inhibition of the fast-reacting group of stromal thiols.
MEMBRANE SPECIFICITY OF LEUCONOSTOC MESENTEROIDES FOR THE STEREOISOMERIC FORMS OF GLYCINE AND VALINE DIPEPTIDES
Authors: Yoder Omar C. , Beamer Kathryn C. , Shelton Damon C.
Published: December 2009

Transport systems of Leuconostoc mesenteroides differ greatly in the stereochemical specificity exhibited for amino acids and dipeptides. Nongrowing cell suspensions of this organism accumulated D- and L-valine to approximately the same extent, whereas no measurable transport of valine from glycyl-D-valine occurred. In concurrent studies, however, a very high uptake of valine was found from glycyl-L-valine. Stereospecific synthesis of the various radioactive valine dipeptides permitted more extensive studies. No valine transport was found from any of the isomeric forms if D-valine was one of the amino acid moieties. Consistent with these observations, no hydrolysis of any dipeptide by intracellular dipeptidases could be detected when D-valine was a part of the peptide. This difference in stereochemical specificity supports the concept of separate transport sites for amino acids and related dipeptides.
REGULATION OF THE INITIATION OF HEMOGLOBIN SYNTHESIS IN THE BLOOD ISLAND CELLS OF CHICK EMBRYOS: III. QUALITATIVE STUDIES OF THE EFFECTS OF 8-AZAGUANINE AND PREPARATIONS OF TRANSFER RNAs
Authors: Wainwright S. D. , Wainwright Lillian K.
Published: December 2009

High concentrations of actinomycin D caused markedly greater inhibition of the incorporation of3H-uridine than concentrations adequate to totally inhibit synthesis of all RNAs of high molecular weight during short periods of incubation.8-Azaguanine markedly inhibited the formation of hemoglobin and the incorporation of leucine into protein by blastodiscs explanted prior to the 6-somite stage of development. This inhibition took place at later stages of development than the inhibition by actinomycin resulting in total arrest of messenger RNA synthesis. Inhibition of hemoglobin formation by 8-azaguanine was reversed by δ-aminolevulinic acid, without reversal of the inhibition of leucine incorporation.Preparations of amino-acylated bacterial transfer RNAs and of yeast and mammalian transfer RNAs partly or largely reversed the inhibition of hemoglobin formation by high concentrations of actinomycin. Preparations of "stripped" bacterial transfer RNAs were inactive. An active preparation of "charged" bacterial transfer RNA did not reverse inhibition of leucine incorporation by actinomycin. This preparation reversed the inhibition of hemoglobin formation by 8-azaguanine and partly reversed the inhibition of leucine incorporation due to the analogue.
SYNTHESIS OFL-α-PHOSPHATIDYL-(α-METHYL)CHOLINES
Authors: Baer Erich , Pal Bimal C.
Published: December 2009

The synthesis of a new group of phospholipids, L-α-phosphatidyl-DL-(α-methyl)cholines is reported. Three homologous members of this group were prepared by phosphorylating D-α,β-dimyristin, D-α,β-dipalmitin and D-α,β-distearin, respectively, with phenylphosphoryl dichloride and pyridine, esterifying the resulting phenyl esters of the L-α-phosphatidic acid monochlorides with DL-(α-methyl)choline iodide, replacing the iodide ion of the L-α-phosphatidyl-DL-(α-methyl)choline phenyl esters by acetate ion, and removing the phenyl group by catalytic hydrogenolysis.
CONVERSION OF THE PLANT GROWTH RETARDANT (2-CHLOROETHYL)TRIMETHYLAMMONIUM CHLORIDE TO CHOLINE IN SHOOTS OF CHRYSANTHEMUM AND BARLEY
Authors: Schneider E. F.
Published: December 2009

In barley and chrysanthemum shoots, (2-chloroethyl)trimethylammonium chloride (CCC) was converted to a compound chromatographically identical with choline. Labeled choline and several other labeled metabolites were isolated from plant tissues that had been placed in solutions containing methyl- or ethyl-labeled CCC. These results indicate that the carbon skeleton remained intact during the conversion. The unknown metabolites were identical with those isolated from plants that had received choline or choline plus CCC. An additional compound, found only after CCC treatment, may be an intermediate in the conversion of CCC to choline.
THE WHEAT LEAF PHOSPHATASES: VIII. A PREPARATION WITH PHOSPHOTRANSFERASE ACTIVITY
Authors: Roberts D. W. A.
Published: December 2009

The nucleoside phosphotransferase of wheat leaves has been separated from the acid β-glycerophosphatase (EC 3.1.3.2) by chromatography on the weak base anion exchange resin Rexyn 203. The preparation is contaminated with 3′-nucleotidase (EC 3.1.3.6), acid pyrophosphatase (EC 3.6.1.1), and a phosphotransferase that apparently catalyzes the interconversion of adenosine 3′-phosphate and adenosine 5′-phosphate. The low level of acid β-glycerophosphatase activity in these preparations proves the existence of an active acid pyrophosphatase in wheat leaves that is distinct from classical acid phosphomonoesterase, which is supposed to hydrolyze pyrophosphate.
CHARACTERIZATION OF RAT LIVER AND KIDNEY ESTERASES
Authors: Schwark W. S. , Ecobichon D. J.
Published: December 2009

Vertical zone electrophoresis in starch gel was employed in conjunction with various histochemical techniques to characterize the liver and kidney esterases of male and female rats. Tissue-specific patterns were observed for each organ and a sex-dependent difference was noted on electrophoretic separation of the liver extracts. On the basis of substrate specificity and inhibitor sensitivity, both organs were observed to contain similar nonspecific aliesterases or carboxylesterases (EC 3.1.1.1). Inhibition studies showed the presence of two types of aliesterase in the liver and kidney extracts.
THE EXTRACELLULAR PROTEINS OF ACETOBACTER XYLINUM AND THEIR RELATIONSHIP TO CELLULOSE SYNTHESIS
Authors: Webb T. E. , Colvin J. Ross
Published: December 2009

Proteins and dialyzable substances which also react with Folin's reagent are released from washed cells of Acetobacter xylinum immediately upon resuspension of the cells in buffer at pH 6.0. Incubation of the cells without an energy source leads to an additional gradual loss of dialyzable material and proteins from the cells to the medium. Much of the soluble protein disappears from the medium if the pH is allowed to drop below 6.0. This decrease in concentration of soluble protein is probably due to pH-dependent adsorption to the cell walls or to precipitation of the protein. The extracellular protein is grossly heterogeneous.All attempts to inhibit the final step of cellulose synthesis by depleting the extracellular proteins of the enzyme which catalyzes the formation of cellulose extracellularly, failed. This failure is attributed to the strong adsorption of soluble proteins, including the enzyme, to the cells. Use of a microassay method for cellulose confirmed the existence of the enzyme which catalyzes the synthesis of cellulose from an ethanol-soluble precursor. The properties and significance of this enzyme in relation to the celluloseless mutants of A. xylinum are described.
CELLULAR POLYSACCHARIDES OF SERRATIA MARCESCENS
Authors: Adams G. A. , Martin S. M.
Published: December 2009

Decapsulated cells of Serratia marcescens were fractionated to yield crude cytoplasmic (I) lipopolysaccharide (II) and cell-wall (III) polysaccharides. Further separation of I yielded dialyzable polysaccharides composed of D-glucose and D-mannose and nondialyzable polysaccharides containing various proportions of D-glucose, D-mannose, L-rhamnose, glucuronic acid, and glucosamine. Fractionation of II by precipitation with Cetavlon–boric acid and by highspeed centrifugation yielded polysaccharides containing D-glucose, L-rhamnose, D-mannose, D-glycero-D-manno-heptose, L-glycero-D-mannose-heptose, glucuronic acid, mannuronic acid, and glucosamine. Analytical data on the various fractions indicated that these polysaccharides included an acidic glucomannan, a rhamnoglucan, and a heptoglucan. Polysaccharides of similar composition have been found in S. marcescens capsular and extracellular polysaccharides in an earlier investigation. Removal of the mucopeptide material from the cell-wall III left an insoluble polysaccharide residue composed of glucose and glucosamine units.
AN ANALYSIS OF THE LIPIDS OF GRYLLUS BIMACULATUS (DEGEER) (INSEGTA, ORTHOPTERA)
Authors: Fast Paul G.
Published: December 2009

The lipids of the cricket Gryllus bimaculatus (DeGeer) have been analyzed by thin-layer and gas–liquid chromatography. Choline phosphoglyceride (54.2%) and ethanolamine phosphoglyceride (35.4%) comprised most of the phospholipids. Smaller amounts of sphingomyelin and an unidentified acidic phospholipid were found. Linoieic acid made up roughly 50% of the fatty acids in each phospholipid class.
DISTRIBUTION OF HEXOSAMINE IN ELEGTROPHORETIC FRACTIONS OF AVIAN, BOVINE, PORCINE, AND HUMAN SERA
Authors: Gaunce A. P. , Anastassiadis P. A.
Published: December 2009

The distribution of hexosamine among the proteins of avian, bovine, porcine, and human blood sera was studied by electrophoresis on filter paper. Hexosamine was determined after direct hydrolysis of stained sections of the paper, followed by chromatography of hydrolysates on cationic resin. Some substantial and statistically significant differences in hexosamine and protein contents of the zones were found among species.
ETHYLENE PRODUCTION FROM β-ALANINE BY AN ENZYME POWDER
Authors: Thompson John E. , Spencer Mary
Published: December 2009

In the investigation of a pathway for ethylene biosynthesis, intermediates arising from the metabolism of β-alanine-2-14C to ethylene by enzyme powders from wax-bean cotyledons were isolated and identified by paper and thin-layer chromatography. Quantitative determinations of the label have provided evidence for the conversion of β-alanine through malonic semialdehyde, β-hydroxypropionic acid, and acrylic acid to ethylene.
THE BIOSYNTHESIS OF 11-KETOTESTOSTERONE AND 11β-HYDROXYTESTOSTERONE BY ATLANTIC SALMON TISSUES IN VITRO
Authors: Idler D. R. , Macnab H. C.
Published: December 2009

The in vitro synthesis of 11-ketotestosterone and 11β-hydroxytestosterone, from adrenosterone and testosterone, by gonadal and interrenal slices and by sperm was studied. The results establish that adrenosterone is the major precursor of 11-ketotestosterone in both interrenal and testicular tissue. 11β-Hydroxytestosterone was synthesized mainly from testosterone by gonadal and interrenal tissue. The production of 11β-hydroxytestosterone by normal gonadal tissue is reported for the first time.
ADENINE NUCLEOTIDES AND ADENOSINE TRIPHOSPHATASE ACTIVITY DURING AESTIVATION OF THE INDIAN APPLE SNAIL PILA GLOBOSA
Authors: Raghupathiramireddy S. , Swami Karumuri S.
Published: December 2009

Adenine nucleotides were estimated in the tissues of the Indian apple snail during active life and aestivation. In the aestivating snail the level of ATP was significantly higher and that of ADP lower than in the active snail. These changes in the adenine nucleotides were correlated with decreased activity of adenosine triphosphatase in the aestivating snail. The activity of this enzyme was restored to the pre-aestivation level when the snail revived from aestivation. The possible implications of these changes in the regulation of metabolism in the aestivating snail are discussed.
THE INDUCTION OF NAD KINASE BY DDT IN TRIATOMA INFESTANS
Authors: Agosin M. , Ilivicky Jovita , Litvak S.
Published: December 2009

The NAD kinase (EC 2.7.1.23) from Triatoma infestans has been purified and a specific antiserum against it prepared. Immunochemical techniques have shown that the increase in the levels of NAD kinase in nymphs of T. infestans is accompanied by an increase in the amount of enzyme protein. The enzyme is labeled after injection of14C-labeled leucine in both induced and non-induced insects, but labeling is greater in the former, which further supports the concept that a de novo synthesis of enzyme protein occurs during induction by DDT. The enzyme is heterogeneous by DEAE-cellulose and DEAE-Sephadex column chromatography, but the antiserum does not distinguish this heterogeneity. NAD kinase induction may correspond to a protective mechanism of the insects by increasing the availability of coenzymes required for DDT detoxication.
THE DENATURED STATES OF RIBONUGLEASE II
Authors: Sarfare P. S. , Bigelow C. C.
Published: December 2009

Denatured pancreatic ribonuclease has previously been shown to exist in three well-defined states, which are probably sequentially related. All denaturants studied, with one exception, were shown to convert native ribonuclease (N) to one or other of these denatured states (I, II, and III). The exception was very concentrated (~9 M) lithium bromide, which appeared to give another denatured state (IV) with some properties the same as those of II, and some the same as those of III. We have now carried out a thorough investigation of this apparent state IV, by difference spectroscopy and polarimetry. We find that the earlier results were misleading, and in fact that there is no conformation change II → IV, so that we can write a denaturation pathway for ribonuclease simply as: [Formula: see text].
BIOSYNTHESIS OF NUCLEOTIDES IN WHEAT: IV. METABOLISM OF SPECIFICALLY14C-LABELED OROTIC ACID
Authors: Wang Dalton
Published: December 2009

The biosynthesis of pyrimidine nucleotides in wheat leaves was investigated, with specifically14C-labeled orotic acids as precursors. The utilization of orotic acid, unlike uracil, for the synthesis of pyrimidine nucleotides is far more predominant than the degradative process. The labeled orotic acid was rapidly metabolized to uracil nucleotides and the sugar nucleotide, uridine-5′-diphosphate glucose. However, cytosine nucleotides were not significantly labeled within 60 minutes. In spite of the fact that no detectable radioactive OMP was observed, the results presented indicate strongly that the biosynthetic pathway for pyrimidine nucleotides from orotic acid in this plant proceeds according to the following reactions: orotic acid + 5-phosphoribosyl-1-pyrophosphate → orotidine-5′-monophosphate → uridine-5′-monophosphate → uridine-5′-triphosphate → uridine-5′-diphosphate glucose, and uridine-5′-triphosphate → cytidine-5′-triphosphate.
THE EFFECT OF LIPID MICELLES ON MITOCHONDRIAL MALATE DEHYDROGENASE
Authors: Callahan J. W. , Kosicki G. W.
Published: December 2009

Mitochondrial malate dehydrogenase (M-MDH) is known to be very unstable in aqueous solution. This instability may be ascribed to removal of the enzyme by severe extraction procedures from its bound state in the mitochondrion.Whole heart lipid micelles, mitochondrial lipids, and fatty acids increase the stability of the enzyme. The degree of lipid ability to increase activity of M-MDH is dependent on the ionic character of the environment. Thus the enzyme exhibits higher activity in a lipid–phosphate system than in lipid–Tris–acetate or lipid–KCl. Likewise, the enzymatic activity is higher in lipid than in non-lipid media. The relative ability of lipid to stimulate M-MDH activity is independent of pH, ionic strength, and temperature (between 6 and 37 °C). Preliminary evidence suggests that lipid acts by altering the conformation of the tertiary structure of the enzyme.The results, in general, suggest that hydrophobic-group interactions increase enzyme stability. These interactions may, in part, simulate the actual type of binding which stabilizes the enzyme activity in vivo.
SUPPLEMENTATION OF A VEGETABLE PROTEIN MIXTURE
Authors: Guggenheim K. , Szmelcman S.
Published: December 2009

The effect of supplementation with amino acids on the nutritive value of a vegetable protein mixture (VPM) was studied. The preparation consists of 47% autoclaved chick peas, 35% defatted sesame flour, and 18% heat-processed, low-fat soybean flour. Different parameters were studied and casein was used for comparison.The protein efficiency ratio (PER) of the VPM was slightly lower than that of casein. Supplementation with lysine, but not with methionine or tryptophan, increased the PER. Addition of threonine to a VPM diet supplemented with lysine had no marked effect on the PER whereas addition of methionine decreased it.Rats on the diet of VPM gained more weight and had a higher level of total serum protein, liver nitrogen, and RNA than rats on a diet containing the same amount of protein as casein. Addition of lysine to the VPM increased the levels of hemoglobin and serum albumin, and the albumin/globulin ratio of the serum.It is concluded that the nutritive value of the VPM compares favorably with that of casein and that supplementation with lysine raises its nutritive value for rats.
GLUCOSE OXIDATION BY LIVER SLICES FROM THE DOMESTIC FOWL: ACTIVITY OF THE PHOSPHOGLUCONATE-OXIDATIVE PATHWAY
Authors: Duncan H. J. , Common R. H.
Published: December 2009

The value of the quotient, 14CO2 liberated from glucose-1-14C over 14CO2 liberated from glucose-6-14C, for chicken liver slices has been determined. It did not deviate appreciably from unity for slices from (a) immature and sexually mature females, (b) a group of females at intervals during their transition from sexual immaturity to sexual maturity, (c) immature males, and (d) immature females treated by injection with estradiol monobenzoate. Incubation of the liver slices under anaerobic conditions reduced CO2 liberation to very low values and approximately doubled the quotient. Incubation in the presence of arsenite reduced oxidation but increased the quotient about fourfold. Incubation under anaerobic and aerobic conditions, with addition of pyruvate, increased the quotient value.It is concluded that the phosphogluconate-oxidative pathway, if active at all in chicken liver, plays a subordinate role in carbohydrate metabolism in this tissue compared with its role in carbohydrate metabolism in rat liver.
THE β-OXIDATIVE DEGRADATION OF DOCOSENOIC ACIDS TO EICOSENOIC AND OCTADECENOIC ACIDS IN THE RAT
Authors: Craig B. M. , Beare Joyce L.
Published: December 2009

Methyl esters of monoenoic acids from rat tissue lipids were prepared and isolated by silver nitrate – silicic acid column chromatography and further separated according to chain length by preparative gas–liquid chromatography. Each monoenoic fraction was then oxidized for subsequent gas–liquid chromatography to distinguish isomeric intermediates of β-oxidation.Cetoleic acid (11-docosenoic), an isomer of erucic acid (13-docosenoic), was dagraded by the rat to gadoleic (9-eicosenoic) and 7-octadecenoic acids. By analogy, dietary erucic acid would contribute to the content of 11-eicosenoic and oleic (9-octadecenoic) acids in the tissue lipids.
STUDY OF SOME FACTORS THAT AFFECT THE DISTRIBUTION OF NUCLEAR VOLUMES IN PREPARATIONS OF RAT LIVER NUCLEI
Authors: Umaña Roberto
Published: December 2009

The effect of the homogenization procedure, the centrifugation scheme, and the composition of the suspension medium on the distribution of nuclear volumes has been studied.It has been shown that the Waring Blendor not only destroys a greater number of the nuclei during homogenization, but also that this destruction is a selective one. At neutral pH values, no direct relationship appears to exist between the DNA content of the nuclei and their density. For this reason, purification in concentrated sucrose solutions produces a selective loss of the lighter nuclei, which includes small diploid stromal nuclei and some of the larger polyploid type of parenchymal nuclei.The study of the effect of increasing the calcium and magnesium ion concentrations (from 0.001 to 0.005 M) on the nuclear distribution showed that these ions produce a selective shrinkage and condensation of the nuclei, probably through different mechanisms.
THE EFFECT OF PROTEIN DEFICIENCY ON THE DISTRIBUTION OF NUCLEAR VOLUMES IN PREPARATIONS OF RAT LIVER NUCLEI
Authors: Umaña Roberto
Published: December 2009

The effect of a protein-deficient diet and the subsequent recovery period on the distribution of nuclear volumes has been studied. The results support the hypothesis that protein deficiency produces an increase in the proportion of polyploid-type nuclei in the liver as reflected in an increase in the average content of DNA per nucleus. This increase in polyploidy was shown to occur early in the experimental period, suggesting that it represents part of an adaptation mechanism more than a secondary effect produced by the deficiency of amino acids. Throughout the study, it was not possible to demonstrate any relationship between patterns of nuclear volume distribution or the average nuclear volume, and the average DNA content per nucleus. On this basis, it has been suggested that the nuclear volume might not be a unique function of the degree of ploidy, but most probably is an expression of the protein content of the organelle.
PARTICULATE DIHYDROOROTATE OXIDASE SYSTEM FROM A PSEUDOMONAD: LINKAGE WITH THE RESPIRATORY CHAIN
Authors: Miller Richard W. , Kerr Carolyn T.
Published: December 2009

A particulate dihydroorotate oxidase system was prepared from a soil pseudomonad. Components of the respiratory chain participating in electron transport from dihydroorotate to molecular oxygen are bound non-heme iron, ubiquinone, cytochromes b and c, and cytochrome oxidase. Alternate pathways to oxygen are also operative. Inhibition by conventional respiratory inhibitors was incomplete. Dyes and added cytochrome c were readily reduced by dihydroorotate. Pyridine–adenine dinucleotide coenzymes were not reduced by the substrate. However, oxidase activities for these cofactors may have prevented any net reduction. The primary site of reaction with dihydroorotate probably consists of a dehydrogenase which is linked to the respiratory chain and is reactive with various dyes.In the absence of external electron acceptors or inhibitors, 0.5 mole of oxygen was consumed per mole of dihydroorotate oxidized. The anaerobic rate of reduction of bound cytochrome c, as studied by the stopped–flow technique, was slower than the maximum initial rates of orotate production.
A NEW HEMOGLOBIN VARIANT RESEMBLING HEMOGLOBIN E: HEMOGLOBIN E SASKATOON-β22Glu→Lys
Authors: Vella F. , Lorkin P. A. , Carrell R. W. , Lehmann H.
Published: December 2009

A new hemoglobin electrophoretically indistinguishable from hemoglobin E is described. It was found in a Canadian woman of mixed Dutch and Scottish parentage and was inherited from the Scottish father. Analysis of the tryptic peptides of the whole globin and of the isolated β chain showed that a substitution of glutamic acid by lysine had occurred at position 22 (B4 in Watson and Kendrew's helical notation) of the β chain. In hemoglobin E there is a similar substitution at position 26 (B8) of the β chain.
OXIDATION OF GLUCOSE AND OTHER SUBSTRATES BY EHRLICH ASCITES TUMOR CELLS
Authors: Glick N. , Gillespie E. , Scholefield P. G.
Published: December 2009

The time courses of oxidation of pyruvate-3-14C and of palmitate-16-14C to14CO2in Ehrlich ascites cells are qualitatively and quantitatively similar when expressed in terms of units of acetyl-CoA oxidized. The time courses of oxidation of pyruvate-2-14C and of palmitate-1-14C are also similar to each other, but the delay preceding the attainment of a steady state rate of oxidation is of shorter duration. Similarly, the delay preceding the oxidation of glucose-2-14C at a constant rate is significantly less than the corresponding delay for glucose-6-14C. There is little or no delay with pyruvate-1-14C or giucose-1-14C. All compounds giving rise to acetyl-CoA labeled in the methyl group yield14CO2more slowly than the corresponding compounds in which the acetyl-CoA produced is labelled in the carbonyl moiety. Studies with labeled lactate suggest that as the concentration of lactate increases through glycolysis (and therefore also the concentration of pyruvate) its rate of oxidation increases and an increased rate of production of14CO2from labeled glucose is to be expected. The reason for the long delay preceding the oxidation of glucose-6-14C is hence to be explained partly on the basis of the formation of acetyl-CoA labeled in the methyl moiety and partly because the14CO2produced is derived from lactate and pyruvate which are present at increasing concentrations throughout the experimental period.The rate of oxygen uptake observed when Ehrlich ascites carcinoma cells are incubated with dinitrophenol (DNP) plus glucose, pyruvate, or glutamine is high and is the same for each of these three substrates. It is suggested that, in the presence of glucose, the effect of DNP is to cause oxidation of exogenous substrates rather than to reverse the Crabtree effect.
AROMATIC METABOLISM IN PLANTS: V. THE BIOSYNTHESIS OF CHLOROGENIC ACID AND LIGNIN IN POTATO CELL CULTURES
Authors: Gamborg Oluf L.
Published: December 2009

Studies were made on the biosynthesis of chlorogenic acid and on lignin formation in potato cells from suspension cultures. The cells were incubated with14C-labelled compounds, and the degree of incorporation into chlorogenic acid and into lignin were measured. Shikimic acid and quinic acid were not readily absorbed by the cells, whereas cinnamic acid, p-coumaric acid, and caffeic acid were absorbed very quickly. The results show that quinic acid and caffeic acid can serve as direct precursors of chlorogenic acid in the cells. A large proportion of the14C from the aromatic compounds was incorporated into the alcohol-insoluble fraction, and was associated with a Klason lignin. The lignin aldehydes obtained after nitrobenzene oxidation of the alcohol-insoluble material consisted of p-hydroxybenzaldehyde, vanillin, and trace amounts of syringaldehyde.
FRUCTOSE DIPHOSPHATE ALDOLASE FROM FUSARIUM OXYSPORUM f. LYGOPERSICI: II. CHARACTERISTICS OF THE EXCHANGE REACTION
Authors: Ingram J. M.
Published: December 2009

Fruetose-1,6-diphosphate aldolase purified from extracts of Fusarium oxysporum f. lycopersici was examined in detail. The different pH optima obtained for the proton exchange (pH 6.0) and cleavage (pH 7.5) reactions indicate that this enzyme resembles the yeast FDP-aldolase rather than the aldolase from muscle. When the enzyme was dialyzed extensively, in the absence of Cleland's reagent, it was found that neither the cleavage nor the exchange reaction rates were increased appreciably after addition of mercaptan. Treatment of the enzyme with either methylene blue in the presence of light or with diazosulfanilic acid, two known inhibitors of the cleavage reaction, resulted in almost complete inhibition of FDP cleavage but only a twofold decrease in the exchange capacity. These results substantiate our previous findings that the inhibitors react with residues involved in the D-glyceraldehyde-3-phosphate rather than the dihydroxyacetone phosphate active site.
EFFECT OF TIME FACTOR ON THE NITROGEN SPARING EFFECT OF DIETARY CARBOHYDRATE
Authors: Rao M. Narayana , McLaughlan J. M.
Published: December 2009

The effect of the time factor on the nitrogen sparing effect of dietary carbohydrate was studied in growing rats. During a 10-day feeding period no significant differences were observed in weight gains of rats receiving carbohydrate with the dietary protein (casein) or 8 h after protein was fed. Rats receiving carbohydrate with the protein retained significantly more nitrogen during the first day of the experiment than those receiving protein and carbohydrate separately, but this difference was not evident after the first day.Rats receiving casein alone had elevated plasma amino acid levels, which remained high until carbohydrate was fed 8 h later. The pattern of fall of the amino acids bore a resemblance to the pattern of amino acids in carcass protein.Rats fasted for 16 h had low levels of liver glycogen; when protein was given alone, some was utilized for glycogen formation. Carbohydrate, given 8 h after the protein, increased liver glycogen to normal levels and spared the protein fed at the next meal.
THE INHIBITION OF TRYPTOPHAN PYRROLASE BY ALLOPURINOL, AN INHIBITOR OF XANTHINE OXIDASE
Authors: Becking G. C. , Johnson W. J.
Published: December 2009

The effect of allopurinol (4-hydroxypyrazolo(3,4-d)pyrimidine) on tryptophan pyrrolase activity of rats and mice was determined. After a single intraperitoneal injection of allopurinol at levels equal to or slightly greater than those given orally for the treatment of gout in humans, the drug was found to be an inhibitor of tryptophan pyrrolase activity. After injection of allopurinol, rats excreted significantly less kynurenine, but the drug did not alter plasma tryptophan levels. A study was made of the in vitro inhibition of tryptophan pyrrolase by allopurinol. The drug was found to be a very potent noncompetitive inhibitor of tryptophan pyrrolase with a Ki value of 8 × 10−7 M. Allopurinol at 1.5 × 10−6 M concentration inhibited the enzyme 50%.
FREE RADICALS OF BIOLOGICAL INTEREST: PART II. ELECTRON SPIN RESONANCE (ESR) SPECTRA OF 2537 A IRRADIATED AMINO ACIDS
Authors: Forbes W. F. , Sullivan P. D.
Published: December 2009

Polycrystalline amino acids, when irradiated with 2537 Å light, afford a variety of electron spin resonance signals. These signals are generally stable at room temperature for relatively long periods of time. For a number of the spectra obtained, there is evidence that more than one radical species contributes to the observed spectra. The signals obtained frequently differ from those obtained on exposure to ionizing radiation. The postulated species formed can often be visualized as being formed by effective hydrogen abstraction from the alkyl-substituted tertiary carbon atom or from the —OH, —SH or —NH group contained in the side chain. For L-phenylalanine a secondary radical is obtained, which is ascribed to a cyclohexadienyl radical.
INTRACELLULAR DISTRIBUTION OF COPPER IN THE LIVER OF THE RAT
Authors: Gregoriadis G. , Sourkes T. L.
Published: December 2009

The absolute amount of copper in whole liver and its subcellular fractions decreases as the rat matures. The decrease in mitochondrial and nuclear fractions, which contain most of the copper in the liver of the newborn rat, is much greater than the decrease in the soluble and microsomal fractions. This results in a redistribution of the copper, in favor of the supernatant. In the adult rat, this fraction is about one-half the total copper content of the liver, with the content of nuclei, mitochondria, and microsomes following in that order. The intraperitoneal injection of copper sulfate or the feeding of a diet low in copper brings the copper content of the liver above and below normal levels, respectively, and affects the intracellular distribution as follows. In copper loading, mitochondria and nuclei hold most of the excess and the cytoplasm and microsomes accumulate much less. In copper deficiency, there is a greater loss of soluble and mitochondrial copper and there are minor losses in microsomes and nuclei. The copper concentration in subcellular fractions of the liver seems to be related to the total copper content of the organ rather than to the physiological state of the animal.
AN AUTOMATED METHOD FOR FOLLOWING THE PRODUCTION OF CORTICOSTEROIDS BY ADRENAL TISSUE IN VITRO
Authors: Saffran Murray , Ford Patricia , Matthews E. K. , Kraml M. , Garbaczewska Ljuba
Published: December 2009

A device is described for monitoring the production of corticosteroids by adrenal tissue in vitro. Halved or quartered adrenal glands, distributed equally between two glass vials, were incubated in streams of buffered medium. One vial contained the control and the other the experimental tissue. Sampling of the medium in each vial was continuous; the steroids were extracted automatically, first into methylene chloride and then into ethanolic H2SO4 to develop fluorescence. The acid extracts passed through fluorometer flow cells and the fluorescence was recorded with a two-channel pen recorder. The use of the apparatus is illustrated by a record demonstrating the increase in corticosteroid production in response to ACTH.
BIOSYNTHESIS OF NICOTINIC ACID BY FUSARIUM OXYSPORUM SCHLECHT
Authors: Desaty D. , Vining L. C.
Published: December 2009

When the fungus Fusarium oxysporum was cultured on a glucose–nitrate–salts medium, synthesis of nicotinic acid occurred only during the early growth phase and preceded the accumulation of fusaric acid. Radioactivity from DL-tryptophan-benzene ring-14C was efficiently incorporated into nicotinic acid obtained by acid hydrolysis of the mycelium, whereas DL-tryptophan-β-14C, L-aspartate-U-14C, and sodium acetate-2-14C were poor precursors. Under the conditions of these experiments, all four substrates were poor precursors of fusaric acid. It is concluded that different pathways are used in the biosynthesis of these two pyridine derivatives, the route to nicotinic acid probably involving metabolism of tryptophan via the reactions known to occur in Neurospora crassa.
EFFECT OF VARIOUS AMINO ACIDS ON THE INCORPORATION OF 14C-L-LEUCINE IN THE TISSUE PROTEINS OF NORMAL AND DYSTROPHIC MICE
Authors: Berlinguet Louis , Srivastava Uma
Published: December 2009

Normal and dystrophic mice received daily injections of either water, saline, glutamate, aspartate, glycine, ACPC, or actinomycin D for 5 days. One parallel group of animals received no injections and served as control. On the 6th day after the start of the experiment, all the animals received an intravenous injection of 14C-L-leucine and were killed at various time intervals, ranging from 4 h to 12 days. Daily injections of water or saline to the animals did not cause any change in the incorporation of 14C-L-leucine into various tissue proteins. Glutamate administration increased the retention of 14C-L-leucine in normal muscle but not in dystrophic muscle. A daily injection of aspartate increased the retention of the radioactive amino acid in both normal and dystrophic muscles, the higher increase being found in the dystrophic muscle. Administration of glycine reduced the turnover of proteins in both normal and dystrophic muscles. ACPC (1-amino-cyclopentanecarboxylic acid) or actinomycin D administration caused a decrease in the incorporation of 14C-L-leucine into normal and dystrophic muscles.The continuous injection of glutamate or aspartate for 8 days after the 14C-L-leucine administration caused a very large increase in the retention of the labelled amino acid into the proteins of various tissues of normal and dystrophic mice. It is concluded that variations in the amino acid pools can modify the turnover of proteins, which can be of importance in muscular dystrophy.
Enzymatic oxidation of 14C-Labelled betaine by the marine microbe Achromobacter cholinophagum
Authors: Shieh H. S.
Published: December 2009

When betaine-1-14C was incubated with cell-free extracts from Achromobacter cholinophagum, dimethylglycine was found to be labelled and no radioactivity was present in formaldehyde. When betaine-methyl-14C was used as the substrate, both dimethylglycine and formaldehyde contained radioactivity. The results indicate that the formaldehyde is derived from the methyl carbons of betaine. Betaine demethylation activity was decreased by the fractionation of cell-free extracts with ammonium sulfate, and nicotinamide–adenine dinucleotide has been found to restore the activity significantly.