Some neurochemical aspects of the depressant action of gamma-butyrolactone on the central nervous system

gamma-Butyrolactone, a depressant drug of the central nervous system, has been investigated for its ability to alter brain levels of 5-hydroxytryptamine, gamma-aminobutyric acid and acetylcholine in mice and rats; of these three compounds, only acetylcholine was changed in amount. Levels of acetylcholine in the cerebral cortex were increased by gamma-butyrolactone with a time-course which closely followed the depressed state of the animal. Indirect evidence has been presented to show that in the mid-brain and brain stem the change in acetylcholine level induced by gamma-butyrolactone is sharply localized in an area of the mesencephalon that contains the corpora quadrigemina.

Cell division in a species of Erwinia. V. Effect of metabolic inhibitors on terminal division and composition of a "division" medium

Grula, E. A. (Oklahoma State University, Stillwater) and Mary M. Grula. Cell division in a species of Eriwinia. V. Effect of metabolic inhibitors on terminal division and composition of a "division" medium. J. Bacteriol. 84:492-499. 1962.-Terminal division in Erwinia spp. involves a triggering action and subsequent septum synthesis. It is a metabolic process requiring organic nitrogen and carbon and energy. The process, when triggered by pantoic acid or pantoyl lactone, is inhibited strongly by 2,4-dinitrophenol, hydroxylamine, mitomycin C, and Hg ion and to a lesser degree by cyanide, azide, 5-fluorouracil, and diisopropylfluorophosphate. Ethylenediaminetetraacetic acid completely inhibits division only when calcium ion is the triggering agent. Heating of the cells at 43 C for 10 to 20 min also completely inhibits division. Hydroxylamine, iodoacetate, and mitomycin C cause extensive lysis of growing cells. No evidence has been obtained to demonstrate the need for protein or normal ribonucleic acid synthesis in terminal division. Requirement for intact deoxyribonucleic acid (DNA) or DNA synthesis is questionable; -SH groups are not directly involved. Once triggering has occurred, septum formation appears to require synthesis of at least cell-wall mucopeptide. A "division" medium is reported and discussed.

RETINOYL BETA-GLUCURONIC ACID: A MAJOR METABOLITE OF VITAMIN A IN RAT BILE

The major metabolite in rat bile of injected C(14)-retinoic acid was purified by ion-exchange and silicic acid chromatography; it has the spectrum of methyl retinoate, releases retinoic acid upon basic hydrolysis or by treatment with beta-glucuronidase, and contains glucuronic acid. The metabolite was characterized by treatment with diazomethane followed by hexamethyl-disilazane, or with periodate followed by semicarbazide, and the products were chromatographed. The metabolite has been tentatively identified as retinoyl beta-glucuronide.

REGULATION OF ASCORBIC ACID AND OF XYLULOSE SYNTHESIS IN RAT-LIVER EXTRACTS. THE EFFECT OF STARVATION ON THE ENZYMES OF THE GLUCURONIC ACID PATHWAY

1. The synthesis of ascorbic acid in rat-liver extracts is impaired during starvation, and more from glucuronolactone and glucuronate than from gulonate and gulonolactone. 2. The formation of xylulose from gulonate and from gulonolactone is greatly enhanced during starvation, whereas it is decreased from glucuronolactone and from glucuronate. 3. The activity of the enzymes of the glucuronic acid pathway during starvation has been determined in rat-liver preparations. Gulonolactone oxidase is decreased, NAD-linked gulonate dehydrogenase is enhanced, and uronolactonase, aldonolactonase and NADP-linked hexonate dehydrogenase are unchanged. 4. The impairment of ascorbic acid synthesis from gulonate observed during starvation can be accounted for by the depressed activity of gulonolactone oxidase. 5. The cause of the enhanced formation of xylulose has been located in the sedimentable fraction of liver homogenate. 6. The hypothesis is formulated of an increased utilization of the glucuronic acid pathway during starvation.

STUDIES ON CARBOHYDRATE-METABOLIZING ENZYMES. THE HYDROLYSIS OF ALPHA-GLUCOSIDES, INCLUDING NIGEROSE, BY EXTRACTS OF ALFALFA AND OTHER HIGHER PLANTS

1. Enzyme preparations from 11 plant sources, from yeast and from the protozoan Tetrahymena pyriformis show nigerase activity, which, in most preparations, was 70-90% of that towards maltose. 2. These enzyme preparations also hydrolysed isomaltose, but there was a wide variation in relative maltase to isomaltase activity. 3. The maltase and nigerase activities of alfalfa and tomato preparations could not be differentiated by heat inactivation or inhibitor methods. However, with turanose used as a competitive inhibitor, evidence suggesting that maltose and nigerose are hydrolysed at different catalytically active sites in the alfalfa preparation was obtained. 4. It is probable that the alfalfa alpha-glucosidase exists as a mixture of isoenzymes.

THE CARCINOGENIC ACTION OF AFLATOXIN AFTER ITS SUBCUTANEOUS INJECTION IN THE RAT

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REGULATION OF ASCORBIC ACID AND OF XYLULOSE SYNTHESIS IN LIVER EXTRACTS. THE EFFECT OF STARVATION IN VARIOUS ANIMALS

1. The effect of starvation on the synthesis of ascorbic acid and of xylulose from glucuronolactone and from gulonate has been studied with liver extracts from cats, rabbits, hamsters, mice and guinea pigs. 2. The synthesis of ascorbic acid from glucuronolactone is decreased in all species except cats, and that from gulonate is decreased in hamsters and mice only. 3. The synthesis of xylulose from glucuronolactone was decreased in all species except cats and mice, whereas from gulonate it was enhanced in all the species examined.

THE ANALYSIS OF HEXURONIC ACIDS IN BIOLOGICAL MATERIALS BY GAS-LIQUID PARTITION CHROMATOGRAPHY

A new method for the determination and characterization of hexuronic acids is presented. Hexuronic acid salts are quantitatively reduced by aqueous sodium borohydride to the corresponding aldonic acids which are subsequently converted to their 1,4-lactones. Treatment of the aldono-1,4-lactones with hexamethyldisilazane and trimethylchlorosilane in pyridine solution results in their rapid conversion to the 2,3,5,6-tetra-O-trimethylsilyl-aldono-1,4-lactones, which are sufficiently stable and volatile to allow their separation and quantitative analysis to be made by gas–liquid partition chromatography (g.l.p.c.).The hexuronic acids present in polysaccharides have been identified by acid hydrolysis of the polymers in the presence of platinum and hydrogen, which results in the conversion of the liberated hexuronic acids to their acid-stable aldonic acid derivatives. The O-trimethylsilylated products of the hydrolytic and reductive procedure were analyzed by gas–liquid partition chromatography. The 2,3,5,6-tetra-O-trimethylsilyl-aldono-1,4-lactones arising from the original hexuronic acid residues in the polysaccharides were readily identified. Preparative scale gas chromatography yielded samples of the individual 2,3,5,6-tetra-O-trimethylsilyl-aldono-1,4-lactones, which had characteristic specific optical rotations, infrared spectra, and g.l.p.c. retention times, and which, when they were refluxed with aqueous methanol, gave the unsubstituted parent aldonic acids. This latter procedure affords a microscale method for the identification of hexuronic acids present in polysaccharides.

BETA-PROPIOLACTONE DECONTAMINATION OF SIMIAN VIRUS-40 AS DETERMINED BY A RAPID FLUORESCENT-ANTIBODY ASSAY

beta-Propiolactone vapor treatment of vaccine production facilities has been shown to be approximately 90% effective in the elimination of large quantities of Simian virus-40 (SV(40)). The use of a rapid fluorescent-antibody assay for the detection of SV(40) was also studied.