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1.
Summary The amino acid requirements for moulting, growth and development ofDysdercus similis have been investigated. The insects could not moult and reach maturity when given 10 essential amino acids only. However, if these were supplemented either with glutamic acid, glycine or aspartic acid growth and moulting was found to be normal.Dysdercus has an unusual synthetic mechanism for converting tyrosine into phenylalanine.The author is grateful to Prof.R. S. Saini for his guidance, critical discussions and encouragement.  相似文献   

2.
Summary If certain hybrids ofPlatypoecilus maculatus andXiphophorus helleri (viviparous platyfish and swordtails) are cultivated in diluted sea-water (0.25 or 0.5% salt concentration), the amount of free amino acids increases and the growth of macromelanophores, which normally only form certain black spots at the dorsal fin, is accelerated. Therefore melanomas arise. After changing salt water for fresh water, growth of macromelanophores remains accelerated. The same effect is seen in progenies which have been in an oocytic or embryonic state, when their mother was cultivated for some weeks in diluted sea-water (Figures 1 and 2). A similar effect has been observed in plant galls produced byPhylloxera (Viteus vitifolii) in the genusVitis. When the parasite, which injects amino acids into the tissue of the host in order to produce galls, is removed, gall formation goes on slowly for some days. It is shown that a few hours after injection of amino acids—before formation of neoplasms begins—the concentration of ribonucleic acids is increased. RNS-(and therefore protein-)biosynthesis in neoplasms may be dependent on concentration of free amino acids. A simple concept for the formation of neoplasms in hybrids of platyfish and galls ofPhylloxera is discussed.

Den Herren Prof. Dr.G. de Lattin (Zoologisches Institut der Universität des Saarlandes) und Prof. Dr.B. Husfeld (Forschungsinstitut für Rebenzüchtung Geilweilerhof/Pfalz) sind wir für die Förderung dieser Arbeit zu grösstem Dank verpflichtet. Herrn Prof. Dr.C. Kosswig (Zoologisches Institut der Universität Hamburg) verdanken wir viele Anregungen und die freundliche Überlassung von ingezüchteten Stämmen für unsere Fischkreuzungen. — Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.  相似文献   

3.
Summary Useful biochemical markers for the classification ofActinomycetales are: 1.dl-orll-diaminopimelic acid in the peptidoglycan, 2. sugar composition of polysaccharides, 3. fatty acid spectrum of cell lipids. The occurrence of various kinds of branched fatty acids and of unsaturated fatty acids is of special value.We should like to thank the Bundesministerium für Forschung und Technologie, Bonn, German Federal Republic, for the financial support of this project No. BCT 85.  相似文献   

4.
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.  相似文献   

5.
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.

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

6.
Summary The ribonucleic and thymonucleic acids are antisulphamide forEremothecium Ashbyii and for aSaccharomyces. This effect is due partly to purines, first of all to adenine, but not to any pyrimidines. ForSaccharomyces, the action of adenine is 1/10 of that of PAB acid. The suggestion is made that the bacteriostatic effect of the sulphamide is connected with the nucleic acids of the cytoplasma and the nucleus. Those are studied cytologically with help of the ribonuclease-method ofBrachet. Strong differences appear between the normal cells and the intoxicated ones.  相似文献   

7.
The d-enantiomers of amino acids have been thought to have relatively minor functions in biological processes. While l-amino acids clearly predominate in nature, d-amino acids are sometimes found in proteins that are not synthesized by ribosomes, and d-Ala and d-Glu are routinely found in the peptidoglycan cell wall of bacteria. Here, we review recent findings showing that d-amino acids have previously unappreciated regulatory roles in the bacterial kingdom. Many diverse bacterial phyla synthesize and release d-amino acids, including d-Met and d-Leu, which were not previously known to be made. These noncanonical d-amino acids regulate cell wall remodeling in stationary phase and cause biofilm dispersal in aging bacterial communities. Elucidating the mechanisms by which d-amino acids govern cell wall remodeling and biofilm disassembly will undoubtedly reveal new paradigms for understanding how extracytoplasmic processes are regulated as well as lead to development of novel therapeutics.  相似文献   

8.
Summary The F1- and FnR-hybrids ofPlatypoecilus maculatus andXiphophorus helleri (Poeciliidae), producing melanomase spontaneously, contain essentially more free amino acids than the initial species. Further experiments show that the abnormally high content of free amino acids is connected with the spontaneous formation of tumors.

Den Herren Prof. Dr.G. de Lattin (Zoologisches Institut Saarbrücken) und Prof. Dr.B. Eistert (Institut für organische Chemie Saarbrücken) sind wir für die stete Förderung dieser Arbeit zu grösstem Dank verpflichtet. Den Herren Prof. Dr.C. Kosswig (Hamburg), Prof. Dr.M. Gordon (New York) und Dr.H. Breider (Würzburg) sind wir für viele Anregungen und die freundliche Überlassung von Zuchtstämmen sehr dankbar. — Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.

F. Anders, F. Vester, K. Klinke undH. Schumacher, Biol. Zbl., im Druck.  相似文献   

9.
    
Summary Methyl poly--glutamate, either of thel ord series, can be saponified with 0.5N sodium hydroxyde in the presence of freshly precipitated copper-II-hydroxyde. It was observed that in this procedure not even partial racemisation takes place, while the average molecular weight of the optically pure acids is of the order 13,000.  相似文献   

10.
Summary Euler (1947) andM. L. Stein (1953) had observed that germinating seeds of barley, rye, wheat and other grasses are colourless when exposed to solutions containing more than 0.2% of streptomycin or dihydrostreptomycin. These plants are not inhibited in growth. The chlorophyll already formed is not destroyed by streptomycin.The present authors describe the bleaching effect on germinating seeds of chlortetracycline and tetracycline. These antibiotics inhibit or reduce the formation of chlorophyll in germinating seeds but the authors could not obtain this inhibition without toxic effects (reduced growth). Contrary to streptomycin, the tetracyclines are not able to precipitate nucleic acids and nucleoproteins.  相似文献   

11.
Zusammenfassung Die Synthese von Arginin-Vasopressin, Lysin-Vasopressin und Oxytocin, deren Glycinrest eine14C-Markierung trägt, wird mit Hilfe der Festkörpermethode nachMerrifield beschrieben.

Supported by National Institutes of Health grants No. AM-13567 and No. AM-10080 and the Atomic Energy Commission.

Abbreviations follow the rules of the IUPAC-IUB Commission on Biochemical Nomenclature in Biochemistry5, 2485 (1966). All optically-active amino acids are ofl-configuration. The following additional abbreviations were used: N-hydroxysuccinimide ester (OSu), ethanol (EtOH), methanol (MeOH), acetic acid (AcOH),n-butanol (n-BuOH), pyridine (Pyr) and N,N-dicyclohexylcarbodiimide (DCCI). Protected peptides and hormones were visualized on thinlayer plates according to the procedure byH. Zahn andE. Rexroth, Z. analyt. Chem.148, 181 (1955). The biological activities of the hormones were measured against the U.S.P. Posterior Pituitary Reference Standard; the four-point design was used for these bioassays and standard errors were calculated according to the method ofC. I. Bliss,The Statistics of Bioassay (Academic Press, New York, N.Y. 1952).

Acknowledgments. The authors wish to thank Mr.D. Schlesinger for some of the amino acid derivatives used, and MissM. Wahrenburg and Mrs.A. Silverman for bioassays.  相似文献   

12.
Summary Seeds ofZornia diphylla possess a complex type of dormancy which is of great survival value for the species. Seeds show polymorphism. The optimum temperature for germination explains the cause of its distribution in the tropics. The grazing and scraping promotes the vegetative growth.The author is grateful to Dr.R. Sahai and Dr.R. S. Tripathi, Gorakhpur University, for guidance and to Dr.Y. B. Singh, Principal, and Dr.G. C. Srivastava, Head Dept. Botany, for encouragement and facilities. Thanks are due to my colleagues late SriP. N. Gupta, SriJ. Abraham, SriF. Abbasi, and Dr.A. B. Sinha for their cooperation.  相似文献   

13.
Summary The addition of citraconic anhydride to 1-vinyl-6-methoxy-3,4-dihydro-naphthalene according toDiels-Alder's method yielded two isomeric hydro-phenanthrene-dicarboxylic acids. One of these two acids has been converted into 2-methyl-7-methoxy-1,2,3,4,9,10-hexahydro-1,2-dicarboxylic-acid.

Mitteilung « Über Steroide » (65. Mitt. siehe Helv. chim. Acta30, 1037 [1947]), sowie XX. Arbeit « Über östrogene Carbonsäuren » (XIX. siehe Exper.3, 279 [1947]).  相似文献   

14.
Summary A device for the small-scale generation of diazomethane is described, as well as the methylation by this reagent of nanogram amounts of the following fatty acids: butyric, caproic, caprylic, capric, lauric.

3. Mitteilung:S. Huwyler, Experientia28, 1393 (1972).

Herrn Prof. Dr.M. Viscontini danke ich für wertvolle Diskussionen und dem Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung für die finanzielle Unterstützung.  相似文献   

15.
Zusammenfassung Die viruzide Wirkung von Extrakten aus Ahornsamen auf Coli-Bakteriophagen ist durch Tannine bedingt. Verschiedene Gerbstoffe zeigen einen zum Teil sehr starken virushemmenden Effekt, wobei nur das extrazelluläre Virus angegriffen wird. Wahrscheinlich handelt es sich um eine Gerbwirkung auf das Protein des Virus.Die pflanzlichen Gerbstoffe tragen vermutlich dazu bei, die Pflanzensäfte virusfrei zu halten.

While this paper in print, our attention was called to a recent publication in J. Bact. (66, 572 1953) byCarson andFrisch about the growth inhibiting action of tannic acid on influenza virusin ovo. We were ignorant of this work and of the previous publication from 1948 byGreen, Proc. Soc. Exptl. Biol. Med.67, 483 (1948).  相似文献   

16.
Summary Haemolymph ofPalamnaeus bengalensis contains normally 12 and during moulting up to 15 free amino acids, being in maximal number at the end of ecdysis. Aminoacidaemia is most pronounced during the pharate stage. Tyrosine appeared for tanning of the cuticle. Taurine and methionine were not present.Acknowledgment. The author is thankful to Dr.S. C. Shrivastava for valuable guidance and State C.S.I.R. (U.P.) for funds.  相似文献   

17.
Summary (1) A response ofZea mays andPisum roots cultured aseptically to 2,4-dichlorophenoxyacetic acid has been observed.Depending on the concentrationZea mays shows an increase of the growth rate (optimal concentration 10–11 mol) which turns over to an inhibition (above 10–7 mol). The curve is similar to that obtained by 3-indoleacetic acid, which proves the phytohormonal character of 2,4-D.(2) ThePisum root is more sensitive than theZea mays root. A concentration of 10–7 molinhibitsPisum in a high degree, whileZea mays is no more inhibited, thus demonstrating the selective herbicidal action of 2,4-D against isolated roots of Dicotyledons culturedin vitro.  相似文献   

18.
Summary We have reproduced inHordeum the phenomenon described bySchwartz: absence of proportionality at certain dosages, between the dose of roentgen rays and the biological effect when one irradiates dry seeds and measures the growth of the coleoptile. Cytological analysis shows an enlargement of the epidermic cells of the coleoptiles up to 500.000 r and a decrease of the number of mitosis up to 200.000 r dose at which the mitotic inhibition is nearly complete.The phenomenon described bySchwartz disappears progressively if one waits 3 to 20 days between irradiation and sowing.  相似文献   

19.
Bacterial endotoxin and impaired fetal development   总被引:1,自引:0,他引:1  
Summary Small doses ofE. coli endotoxin given to pregnant mice on the 13th day of pregnancy caused only a mild maternal illness but induced resorption of approximately half the number of fetuses in each mouse. The remaining live fetuses developed normally and showed no evidence of retarded growth or malformations. The weights of their placentas and maternal spleens increased significantly. Endotoxin given on the 6th day of pregnancy caused a small reduction in fetal weights.Acknowledgments. I am indebted to Mrs.Heather Sandison for technical assistance and to Mr.M. J. R. Healy for statistical examination of the results. Dr.A. B. G. Lansdown kindly advized on the interpretation of histological findings.  相似文献   

20.
Summary The electron spin resonance was measured with several humic acids. The preparations used here contain stable free radicals. Grey humic acids contain more radicals than brown humic acids.

Herrn Dr.Seifert und Fräulein Dr.Ebert (Deutsche Akademie der Wissenschaften Berlin-Adlershof, Arbeitsgruppe: Physikalische Methoden der Analytischen Chemie, Labor für Hochfrequenz-Spektroskopie; Dir.: Prof. Dr.Kriegsmann) danken wir für die Unterstützung bei der Durchführung der Messungen.  相似文献   

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