Zur leukotaktischen Wirkung von Aminosäuren in Liquor cerebrospinalis

Summary Intercisternal injections of-aminobutyric acid,l-asparagin,l-glutamine,l-leucine andl-norleucine exert a strong leukotactic action and in dogs result after a short time in a maximum cell increase of 76,000/3 cells.     

Über das Verhalten der optischen Isomeren von Adrenalin im Blut

Summary Demethylation ofl- andd-adrenaline was studied on narcotized catsin vivo.In metabolism of infusedl-adrenaline, formation of noradrenaline represents one first step.On the other hand, metabolism ofd-adrenaline does not show any intermediate formation of noradrenaline.     

Effets d'analogues du chloramphénicol sur la différenciation de l'∄uf de l'oursinParacentrotus lividus

Summary The effects ofl-threo-chloramphenicol and thiophenicol on the differentiation of sea-urchin eggs are compared with those exerted byd-threo-chloramphenicol. Onlyd-threo-chloramphenicol caused vegetalization;l-threo-chloramphenicol inhibited development. These effects resemble those of nitrobenzene. Thiophenicol, differing fromd-threo-chloramphenicol by replacing the nitro group with a methylsulphonyl group, slows down development at high concentrations. The effects of chloramphenicol on oxidative phosphorylation and synthesis of proteins are discussed. It is suggested that both the steric configuration typed-threo of the side chain and the presence of a nitro group are necessary for the vegetalizing activity.     

Regionale Inkorporation der optischen Isomeren der Aminosäure Prolin-H3 im Autoradiogramm des Mäusegehirns

Summary Comparative labelling of the mouse brain with tritiatedd, l-proline andl-proline reveals a dissimilarity of incorporation between the optical isomers of this amino acid. The differential regional distribution pattern ofd-proline can be correlated to the cerebral distribution of the enzyme activity ofd-aminoacid-oxidase in the mouse brain.

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Die Arbeit wurde mit Mitteln des Bundesministers für wissenschaftliche Forschung gefördert.     

Stéréochimie d'acides grasα-hydroxylés isolés d'une souche deStreptomyces

Summary A strain ofStreptomyces contains a mixture (ca. 3:1) of 2d-hydroxy-12l-methyltetradecanoic and 2d-hydroxy-13-methyltetradecanoic acids; it has the same properties as a similar mixture prepared by synthesis.

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11e Communication sur la chimie des micro-organismes; 10e communication:C. Lacave, J. Asselineau etR. Toubiana, Europ. J. Biochem.2, 37 (1967).     

Diketopiperazines containing L-proline from Streptomyces lavendulae and their stereochemistry in solution

Summary l-Valyl-l-proline (I),l-leucyl-l-proline (II),l-phenylalanyl-l-proline (III) andl-isoleucyl-l-proline (IV) anhydrides were isolated from the cultures ofStreptomyces lavendulae No. 314 and, on the basis of¹³C-NMR and CD spectra, their stereochemistry in solution is described.Acknowledgments. The authors would like to express their sincere thanks to Prof. H. Ogura, Kitasato University, for kind supply of the authenticl-valyl-l-proline anhydride and to Mr. A. Takakuwa, JASCO, for measuring the CD curves with J-40 automatic recording spectropolarimeter.     

Synthesis of L-4-amino-3-isoxazolidinone,the unnatural stereoisomer of cycloserine and its antibiotic activity

Zusammenfassung Eine direkte Synthese vonl- undd-Cycloserin ausl- undd-Serin wurde beschrieben. Die bakteriostatischen Effekte der drei Formen von Cycloserin (d-,l-unddl-) aufE. coli in synthetischem Medium wurden verglichen.     

Über den Einbau von Dipeptiden in Ergotoxin-Alkaloide

Summary l-Valyl-l-leucine-U-¹⁴C,l-valyl-l-proline-U-¹⁴C-lactam andl-leucyl-l-proline-U-¹⁴C-lactam were administered to submerged cultures of an ergotoxine-mixture-producing strain ofClaviceps purpurea. The added dipeptides were split by the fungus into the corresponding amino acids prior to incorporation. Apparently dipeptides are no immediate precursors for the peptide side-chain of ergotoxinealkaloids.     

Effect of acetylsalicylic acid on iron absorption in the rat

Summary The in vivo administration of⁵⁹Fe to the rat accompanied by acetylsalicylic acid (ASA) enhanced significantly counts in blood, spleen, liver and femur without affecting those of the intestine. The results suggest that ASA augments iron absorption either via an inhibitory action on the synthesis of prostaglandins or by a purely chemical mechanism.This work was supported by Grant No. 6638 from CONICET (Argentina).The technical assistance of Mrs María E. Castro and Mrs Patricia Dubra is gratefully acknowledged.     

Interaction between sugars and amino acids in intestinal absorption by rat, in vivo.

The inhibitory action of L-leucine on the intestinal absorption of D-glucose and D-galactose, as well as the inhibitory action of D-galactose on the absorption of L-leucine at various concentrations by rat small intestine has been studied. The further effect was more clearly evidenced when the medium was perfunded through the intestine in a closed circuit system using a peristaltic pump.     

Uptake ofl-glutamate andl-aspartate in neurones and glial cells of cultured human and rat spinal cord

Summary Autoradiographic investigations on the uptake ofl-glutamate andl-aspartate have shown that the amino acids were taken up by neurones as well as by glial cells of cultured human and rat spinal cord. The activity of glutamate and aspartate varied considerably between individual neurones, whereas glial cells showed a more even distribution of the labelled amino acids. Our results suggest that both neurones and glial cells are involved in the uptake of amino acid transmitters.     

Einbauunterschiede in den Zellschichten des Cortex nach Markierung mitd,l-Prolin-H3 bei der Maus

Summary Autoradiographic studies of the mouse brain following incorporation ofd,l-proline-H³ andl-histidine-H³ show a wide variation of the regional uptake ofd,l-proline into the cerebral nerve cells, in contrast tol-histidine. In the cerebral cortex proline is to be found only in the nerve cells of the lamina ganglionaris (V) and lamina multiformis/infima (VI/VII). Subsequent translocation of radioactivity is indicative of an axoplasmic flow of proline-labelled substances into the distal parts of the neuronal processes.

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Mit dankenswerter Unterstützung durch das Landesamt für Forschung Nordrhein-Westfalen.     

Unstirred layer thickness in perfused rat jejunum in vivo

Summary The effective unstirred layer thickness in the rat jejunum perfused in vivo amounts to at least 530 m. This value has been estimated from the absorption increase ofl-phenylalanine due to better mixing of the luminal solution by air bubbles.     

Synthesis and structure of Fungisporin

Zusammenfassung Die Struktur von Fungisporin, eines Zyklopeptides aus Sporen verschiedener Spezies vonPenicillium undAspergillus-Arten, wird durch Synthese und Vergleich mit dem Naturprodukt als die eines Zyklotetrapeptides, cyclo-(l-Phe-d-Val-l-Val-d-Phe-), bewiesen.     

Fucosidases du suc digestif d'Helix pomatia

Summary The-d-fucosidase and -l-fucosidase activities of digestive juice ofHelix pomatia have been studied.-d-fucosidase can be separated from-d-galactosidase by heat inactivation.     

Cryo-bioorganic chemistry: freezing effect on stereoselection of l- and dl-leucine cooligomerization in aqueous solution

The chirality of l-/dl-leucine (50–50%) cooligomerization was investigated in liquid and frozen aqueous solutions. Cooligomerization was carried out by carbonyldiimidazole activation without initiator at an ambient (+22°C) and frozen (−18°C) temperature, respectively. The separated samples obtained after different time intervals of treatment were completely hydrolyzed (HCl) and the diastereomeric l- and d-leucine derivates of Marfey's reagent (1-fluoro-2,4-dinitrophenyl-5-l-alanine amide) were then traced and evaluated by RP-HPLC analysis. After 9 days of oligomerization, the l-Leu content was slightly enhanced in the liquid (57%) and somewhat more enhanced in the frozen (64%) samples. After 17 days, however, the l-Leu content had decreased in the liquid (53%) and frozen (56%) conditions. These l-enantiomer amplifications indicate that an l-antipode is preferentially incorporated into the α-helical turn of the oligomer in the earlier stage of cooligomerization, while, later, the d-antipode is also incorporated. The role of ice in the improved stereoselection is discussed. This is the first recorded example of the effect of freezing on stereoselection. Received 27 October 2000; revised 11 December 2000; accepted 4 January 2000     

5-Thio-d-glucose:o-diphenoloxidase inhibition as its mechanism of action

Summary 5-Thio-d-glucose completely inhibitedo-diphenoloxidase from animal as well as plant sources. It has been reported that thioglucose suppresses spermatogenesis in mice and also insect metamorphosis, probably through inhibition of glucose transport. Inhibition ofo-diphenoloxidase (which is active in spermatozoa and insect larvae) is suggested as an alternative mechanism of action of thioglucose.     

Avilamycin

Summary A strain ofStreptomyces viridochromogenes produced a new crystalline antibiotic, Avilamycin, related to but not identical with Curamycin and Exfoliatin. Avilamycin, C₆₃H₉₄O₃₅Cl₂, gave on solvolytic degradation the following products: dichloroisoeverninic acid, 2-deoxy-d-rhamnose, 2,6-di-O-methylmannose, 4-O-methylfucose,l-lyxose and 3,5-diacetoxy--caprolactone.     

Kompensation der teratogenen Wirkung eines Thalidomid-Metaboliten durchl-Glutaminsäure

Summary Skeletal defects were observed in the off-spring of SWS-mice following i.p. administration of phthaloyl-l-glutamic acid, a metabolite of thalidomide. The fetuses of animals which receivedl-glutamic acid in addition to the teratogenic drug, did not show any malformations, whereas concurrent i.p. administration of thed-isomer of glutamic acid failed to reverse teratogenicity induced by phthaloyl-l-glutamic acid.