Einfluss von Streptomycin und von Tetracyclinen auf die Entwicklung keimender Samen

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.     

Zur Struktur von Scotophobin

Summary The biological and chemical properties of one of the synthetic peptides Seryl-asparagil-asparaginylasparaginyl-glutaminyl-glycyl-glycy-lysyl-seryl-alanyl-glutaminyl-glutaminyl-glycyl-glycyl-tyrosylamid are identical with those of the natural scotophobin.

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Wir danken der Robert A. Welch Foundation, Houston, Texas, für die finanzielle Unterstützung dieser Arbeit. Herrn Prof. Dr.G. Ungar, Baylor College of Medicine, Houston, Texas danken wir für die Ausführung der biologischen Tests.     

Zur statistischen Verteilung von Generationszeiten

Summary By application of the logarithmic-normal distribution of the generation timeT, it is confirmed that, in contrast to the 1/T-distribution, the deviation does not depend on the size of the mean.     

Zur entwicklungsphysiologischen Wirkungsanalyse von antimitotischen Stoffen

Summary The cleavage mitoses of eggs of the fresh-water oligochete Tubifex may be irreversibly blocked, if treated during a relatively short time by solutions of certain antimitotic substances (benzoquinone, naphthoquinone or colchicine). It is also possible to inhibit tail regeneration in tadpoles of Rana or Xenopus by a single colchicine treatment during only 30 to 60 minutes. It is discussed whether this is due to irreversible loss of regeneration capacity or simply to an inhibition of the first regeneration processes.     

Zur Biosynthese von Reserpinin und Vincamedin

Summary The biosynthesis of reserpinine (II) and vincamedine (IVa) in Vinca plants has been investigated with the help of labelled precursors. Incorporation of 1-¹⁴C-Sodium acetate into the non-tryptophan C₁₀-moiety of these alkaloids occurred only with extensive randomization of the label. In addition, indications were obtained that the methyl group of methionin is not involved in the formation of this fragment.     

Zur Wirkung von Strahlenschutzstoffen an Thymuszellen

Summary Lymphocytes of the thymus can be protected against early pycnotic degeneration by several SH-compounds. Protective and non-protective SH-compounds induce the same reaction in the non-irradiated mouse, weight loss caused by cell migration, stimulation of the reticulum. A direct relationship between the activity of the reticulum and the radioresistance of lymphocytes was not found.     

Zur Blutdruckwirkung von Aludrin und Adrenalin

Summary The depressor action of small doses of adrenaline on the blood pressure (B.P.) of the decapitated cat may be abolished by pretreatment with pilocarpine; atropine restores the original depressor action. The fall in B.P. due to adrenaline after ergotamine once more becomes an increase when pilocarpine has been given earlier. After atropine a fall in B.P. again occurs. This effect of pilocarpine and atropine on a depressor response has already been described in the case of Aludrine (N-isopropyl-noradrenaline) byFromherz.     

Zur bakteriziden Wirkung von komprimiertem Sauerstoff

Summary In this article the writer suggests an explanation for the germicide effect of compressed oxygen. The production of poisonous products of metabolism can be ignored, because the bacterial development is normal after removal of the pressure. Lack of nutritive material through inhibition of metabolism and permanent damage to the enzymes is also not a satisfactory explanation. The possibility is discussed that oxygen as an acceptor of electrones creates an ionisation of important parts of the cell and resulting in the death of the bacteria. The effect seems to be similar but weaker than that of H₂O₂.     

Zur Bildung von Carbonylverbindungen in Fetten nach Einwirkung von Elektronenstrahlen

Summary Investigations of the formation of carbonyl compounds in fats subjected to electron rays (100 Mrad) have been reported. More than 20 different substances can be determined by gasliquid-chromatography. The splitting of the ester-C-O-C-bonds is mostly accompanied by a fracture of the fatty acid chain and carbonyl compounds with 6 to 12 C-atoms are essentially formed (aldehydes mostly up to 9 C-atoms). A relatively high concentration of unsaturated C₉-ketones and a small amount of ketones with more than 13 C-atoms has been found in irradiated tripalmitin and palmitic acid. None of these higher compounds could be detected in unsaturated oils, which contain more C₁₁- and C₁₂-ketones.     

Zur Stereochemie der enzymatischen Dehydrierung von Butyryl-CoA

Summary The stereochemistry of the formation of crotonyl CoA from butyryl CoA catalyzed by the appropriate pig liver enzyme was investigated using samples of butyric acid specifically labelled with tritium in the two methylene groups. It is shown that oxidation involves specific removal of the pro-R hydrogen atoms from positions 2 and 3 of the substrate.     

Zur Kenntnis von Levorin A und Candicidin

Summary A sample of Russian provenance of the antifungal antibiotic levorin A, containing 30,000 microbiological units of activity/mg, was shown to consist of several components. Three components, designated levorin A₁, A₂ and A₃, were isolated and shown to be distinguishable by their partition coefficients in the system chloroform-methanol-borate buffer pH 8.4 (2:2:1). An enriched sample of the antifungal antibiotic candicidin, prepared from a commercial preparation of American provenance, showed a very similar pattern of distribution as levorin A did in 600 transfers. Levorin A₂, the main component of the levorin A sample, was not distinguishable within the error limits of the applied tests, from the main component of the enriched candicidin sample.

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64. Mitteilung der Reihe «Stoffwechselprodukte von Mikroorganismen». 63. Mitteilung: Experientia, im Druck (1968).     

Zur Wirkung von Zn++ auf die Nukleinsäurebiosynthese von Aszites-Tumorzellen

Summary Ascites tumour cells have been employed to study the reactivity of Zn⁺⁺ on nucleic acid biosynthesis. 10^–4 M Zn⁺⁺ caused a selective inhibition of DNA synthesis of intact cells. The rate of RNA- and protein-biosynthesis, however, remained unchanged. The activity of DNA polymerase as well as DNA dependent RNA polymerase was strongly affected by Zn⁺⁺ in vitro.     

Zur Biosynthese von Biopterin in Säugetieren

Summary Biosynthesis of biopterin in mice and rats was studied. After vascular injection of¹⁴C-GTP (U) in mice and rats, radioactive biopterin was isolated from the urine. The specific radioactivity of 6-carboxypterin obtained by oxidation of biopterin was proved to be 7/9 that of biopterin. The result definitely shows that biopterin is biosynthesized from GTP in mice and rats, and the sidechain of biopterin is derived directly from the ribose moiety of GTP.     

Zur Frage des Vorkommens von N-Nitroso-Verbindungen im Tabakrauch

Summary Important facts in connection with the occurrence of N-Nitroso compounds in tobacco smoke have been summarized. This paper reports on analytical methods for the identification of N-Nitroso compounds. The figures known about nitrate content and volatile bases of tobacco, as well as the nitrogen oxides and volatile bases of tobacco smoke as precursors of N-Nitroso compounds, are summarized. The third order reaction of secondary amines with an equimolar mixture of nitric oxide and nitrogen dioxide is a precondition for the formation of N-Nitroso compounds in tobacco smoke. While examining tobacco smoke for N-Nitroso compounds, temperature and time conditions have to be adapted to the natural smoking process. The use of solvent as well as cold traps has to be avoided to exclude the formation of artifacts. Analyses completed under these conditions furnished results of 0.004µg of a mixture consisting of N-Nitroso-dimethylamine and N-Nitroso-pyrrolidine, calculated as N-NO per cigarette. A number of animalexperimental preconditions are still lacking, to judge the biological effects of these extraordinarily small amounts of N-Nitroso compounds.     

Zur polarographischen Untersuchung von Peroxiden und oxydierten Fetten

Summary The origin of the polarographic peak between 0 and –0.2 V caused by oxidized fats and by different peroxides, especially diacyl peroxides dissolved in LiCl in methanol/benzene, has been investigated with a cathode ray polarograph. This peak is caused by a reduction of Hg-ions. Certain peroxides favour the oxidation of the Hg-metal of the electrode to Hg-ions; thereby the diffusion current is proportional to the peroxide concentration. An addition of Hg-ions to the peroxide solution increases the peak height. Hg²⁺- and Hg⁺-solutions without peroxide yield a similar peak.     

Zur « Lipoidlöslichkeit » von Arzneimitteln

Summary The solubility of phenazon, 4-aminophenazon and aminophenazon in heptan, neatsfoot oil, lard, lecithin and chloroform was determined. The results demonstrate that the solubility in chloroform or heptan cannot be taken as a measure of the fat-solubility, and that the solubility of phenazon in lipids has to be taken into consideration in determining the so-called antipyrinspace as a measure of total body water.     

Zur Pharmakologie von Convallatoxol,zugleich ein Beitrag zur pharmakologischen Strukturanalyse von g-Strophanthin

Summary A report is given of the positive inotrope effects of genins and glycosides with one methyl or aldehyde or carbinol group in the C₁₀ atom of the steroid stage, and of the influence of thel-rhamnose compared withd-digitoxose andd-cymarose. A structure analysis of the ouabain and convallatoxol is derived from the differences in the degree of abolition of the acute cardiac damage in the experiments.     

Zur Bindung von Biliverdin an das Protein im Crenilabrus-Blau

Summary The blue biliprotein from the fins of the Mediterranean fishCrenilabrus pavo C.V. was analysed with respect to linkages between colouring matter (biliverdin IX) and apoprotein. It was shown by chromic oxidation under various conditions and determination of degradation products that one of the outer and one of the inner rings of biliverdin are free. The remaining inner ring is bound to the apoprotein presumably by an ester bond, while the lability of the linkage between one outer ring and apoprotein corresponds to a N-acyl-bond.     

Zur Wirkung von Colchiceinamiden an Zellenin vitro undin vivo

Summary Colchiceine-N-mono-methylamide is 3–4 times as active as colchicine as shown by its effect on the mouse-ascites-tumor (Ehrlich) and on fibroblastsin vitro.     

Zur Austestung von Wachstumsinhibitoren für Tuberkelbazillenin vitro

Summary The addition of serum or Tween 80 to a synthetic culture medium for tubercle bacilli considerably reduces the inhibitory effect of various substances with the exception of streptomycin and promin, whose effect is less weakened, and which retain their tuberculostatic action to a considerable degree. The antagonistic effect of Tween 80 is still recognizable in small dilutions where its diffusion effect can no longer be observed.

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Die Arbeit wurde durch einen Arbeitsbeschaffungskredit des Bundes ermöglicht, für dessen Gewährung wir auch an dieser Stelle danken.