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.     

Molekulargewichtsbestimmung von Kalbsherzmyosin

Summary Sedimentation and diffusion coefficients, partial specific volume, intrinsic viscosity, ATP-ase activity and molecular weight of cardiac myosin from calf hearts were determined. The values agree well with the results ofMueller et al.⁴ for cardiac myosin of the dog, and are not essentially different from values reported for skeletal myosins.¹      

Elektronenspinresonanzmessungen zur Untersuchung von Kinetik und Mechanismus von Cu2+-katalysierten Reaktionen

Summary Cu²⁺-complexes with different monodentate ligands PYR, e.g. pyridine, 2,4,6-collidine and imidazole, catalyse the oxidation ofo-phenylenediamine (H₂B) to 3,5-dihydro-2-amino-3-iminophenazine (PHEN) by O₂. Investigation of the electron paramagnetic resonance during reaction gives interesting details on the function of Cu²⁺ as a catalyser. The formation of mixed complexes (H₂B)Cu²⁺(PYR) and its influence on the reaction rated[PHEN]/dt is demonstrated. In the ratedetermining reaction, Cu²⁺ is reduced to Cu⁺, which is reoxidized by O₂. During reaction the ratio [Cu²⁺]/[Cu⁺] is determined by means of e.p.r. measurements.     

Zum Reaktionsmechanismus von Oxydasen

Summary The reactivity of copper(I)-complexes towards molecular oxygen in relation to some copper containing enzymes has been studied. The oxydation of simple amine-complexes proceeds at a rate of about 10³–10⁴ Mol^–1 Lt Min^–1. Replacing the amine by amides and peptides has a strong retarding effect. A copper(I)-cysteine complex exhibits the interesting property of adding O₂ reversibly.     

Gitterkonstanten und Raumgruppe von Tetrammincuprisulfat

Summary The space-group of Cu(NH₃)₄SO₄·H₂O isD _2h ¹⁶ orD _2h ¹³ (D _2h ⁵ , D _2h ¹ ) with a=7,07, b=12,12, c=10,66 Å ± 1%.     

Abbau von Quarz mit Brenzkatechin

Summary Fine divided HF-etched quartz was dissolved in a 0.2M solution of pyrocatechol at pH 9.6. Between 17 and 40 °C the dissolution rate (v _s ) follows the equation: logv _s =0.0295 T-20.87 At 25 °Cv _s amounts to 0.8 · 10^–12 g cm^–2 sec^–1. With several phenols the dissolution rate of quartz decreases in the order: pyrocatechol > pyrogallol > 2, 3-dihydroxynaphthalene.     

Die Einlagerung von radioaktivem Schwefel in die Flügel von Acrididen nach Applikation von35S-Natriumsulfat-und35S-l-Cystinlösungen

Summary Psophus stridulus L. andOedipoda coerulescens L. were fed or injected with solutions of Na ₂ ³⁵ SO₄ and³⁵S-l-cystine. The radioactive radiation pattern of the wings was found to depend on the time of application. Differences in radiation intensity were found to correspond to the red, blue and dark areas.     

Kinetik der hepatischen Farbstoffaufnahme von Indocyaningrün. Einfluss von Bilirubin und Natriumglykocholat

Summary Kinetics of hepatic uptake of indocyanine green, a dye which is used for evaluation of liver function, were studied in the rat. The results indicate that the relationship between ICG-dose and initial hepatic dye uptake obeys Michaelis-Menten kinetics suggesting an interaction of the dye with a carrier or fixed site in the liver cell. Thus it was possible to calculate maximum ICG-uptake (v _max ) and the Michaelis constant (K _m ) of this transport system from several submaximal values.v _max was 7.65 (6-06-9.65)²² mg per 100 g liver/min and K _m 0.56 (0.31–0.81)²². Under the influence of substances which inhibit the elimination of dyes by the liver the parametersv _max and K _m showed changes which allowed characterization of the type of inhibition. While sodium glycocholate had no influence on maximum hepatic ICG-uptake and the Michaelis constant bilirubin caused a significant increase of K _m to 1.29 (0.68–1.90)²² without significantly changingv _max . These data suggest that bilirubin interferes with hepatic uptake of indocyanine green by competitive inhibition and that uptake of bile acids is dependent on a different mechanism.     

Reinigung von F-antigen

Summary F-antigens are glycoproteins with s ₂₀ ^c , 0.1M NaCl=5.4 and a main component in SDS-polyacrylamide of molecular weight of 40,000. Separation of F-antigens is described; with the methods used they are indistinguishable.

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Arbeit mit Unterstützung des Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung (Kredit Nr. 5254.3). Herrn Dr.H. Mosimann danke ich für die Hilfe bei der analytischen Ultrazentrifugation, Frl.U. Kohler für Mitarbeit und Herstellung der Skizzen.     

Die Wirkung von Spirolactonen und von Herzglykosiden auf den Natrium- und Kaliumtransport an Erythrocyten

Summary Experiments made on human red cells showed that spirolactones (SC 5233 and SC 9420) added to the sample as dry powder (10^–3 g/ml) exert an inhibitory action on the active transport of sodium and potassium across the cell membrane. Spirolactone at its saturation concentration in serum (1.5×10^–5 g/ml), however, was ineffective.The inhibitory action was not affected by aldosterone or hydrocortisone.Experiments involving exposure of red cells to spirolactone and a cardiac glycoside simultaneously led to the conclusion that these substances do not have the same mechanism of action. The inhibition caused by spirolactone added to the inhibition due to a supramaximal concentration of ouabain (5 × 10^–4).

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Diese Arbeit wurde unterstützt durch ein Stipendium der CIBA für naturwissenschaftliche, medizinische und technische Forschung.     

Die Wirkung von Na3[Ca-DTPA] auf den Glykogengehalt von Niere und Leber der Ratte

Summary DTPA, a derivative of EDTA, in doses of 1, 2, 4, and 8 mmoles kg^–1/d ^–1 causes a histochemically detectable increase of glycogen in the kidneys and a decrease of glycogen in the liver of rats. Furthermore, a severe damage of the intestinal mucosa has been demonstrated; its possible relevance for the pathogenesis of the other findings is discussed.     

Metallionen-katalysierte hydrolyse von adenosintriphosphat

Summary Some kinetic and structural data on the catalysis exerted by Cu²⁺ in the hydrolysis of ATP are given.     

Beeinflussung der ATPase aminspeichernder Granula von Nebennierenmark und Milznerven durch Thallium

Summary ATPases of the amine storing granules from bovine adrenal medulla and splenic nerves are inhibited by Tl⁺⁺⁺ 3×10^–5 and 5×10^–6 M, respectively. Tl⁺ up to 10^–3 M is ineffective. By T1⁺⁺⁺ in concentrations of 10^–4 M or more, proteins are precipitated, so that the enzyme inhibiton by these concentrations is unspecific. If T1⁺ is oxidized to Tl⁺⁺⁺ in the organism, the inhibition of granular ATPase may be responsible for the alterations of the catecholamine metabolism observed in thallium intoxication.     

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.     

Aufnahme von thymidin durch mastocytomzellenin vitro unter der einwirkung von podophyllumstoffen

Summary SP-G and SP-I, two podophyllum preparations with spindle poison activity, were tested for their effect on³H-thymidine incorporation into P-815 mastocytoma cellsin vitro. Concentrations which inhibited cell multiplication completely did not affect DNA-synthesis as measured by thymidine incorporation.     

Die Wirkung von Makrotetralidantibiotika auf photosynthetische Reaktionen in Spinatchloroplasten

Summary The macrotetralid antibiotic Dinactin uncouples phosphorylation from electron transport in illuminated chloroplasts in the presence of Na⁺ at lower concentrations than in K⁺, while the light-induced proton uptake is more inhibited in a medium with K⁺ than with Na⁺. The large volume changes of whole chloroplasts in the light and after addition of Dinactin are parallel to the amount of K⁺ in the chloroplasts.

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Die Resultate der vorliegenden Arbeit entstanden zusammen mitElisabeth Bosshard-Heer, H. R. Hohl, Ch. Pflugshaupt undIngrid Specht-Jürgensen. Wir danken dem Schweizerischen Nationalfonds für die grosszügige Unterstützung.     

Mikrobiologische Oxydation von Steroiden durch Cephalosporia

Summary It was found that members of the Cephalosporium species transform steroids under the known conditions of microbiological oxydation. Cephalosporium subverticillatum is able to produce ⁴-testoloactone from progesterone, but, in case of a longer fermentation period, ⁴-androsten-3, 17-dione can be isolated from the broth.     

Der Einfluss von Colchizin und Ethidium-Bromid auf den Gehalt radioaktiv markierter Uridin-Verbindungen in optischen Axonen von Teleosteern

Summary After application of colchicine to one eye, and subsequent injections of³H-histidine or³H-uridine into both eyes, a blockage of the transport in the optic system of teleosts could be demonstrated only for the fast protein-components. However, colchicine is able to depress the effectivity of ethidium-bromide, a blocker of mitochondrial RNA-synthesis. This finding is discussed in connection with the possibility that axonal mitochondria are associated with the neurotubules.

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Mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft, die Herrn Prof. Dr.H. Rahmann (Münster) die Mittel zu dieser Untersuchung zur Verfügung stellte.     

Zum Vorkommen von Thiothreonin im Pflanzenmaterial

Summary In extracts of H₂ ³⁵S gased pea seedlings, a radioactive substance has been revealed by thin layer chromatography which showed the same chromatographic properties as thiotheronine.     

Photolyse von N-Nitroso-22,26-iminocholestanen: Eine neue Synthese von Spirosolan-Alkaloiden

Summary Photolysis of N-nitroso-22,26-imino-5-cholestane-3,16-diols in acidic solution leads to the corresponding spirosolane alkaloids soladulcidine, solasodine and tomatidine, respectively.

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Photochemische Reaktionen, 5. Mitteilung. — 3. und 4. Mitteilung vgl.². Die vorliegende Arbeit ist zugleich 62. Mitteilung der ReiheSolanum-Alkaloide.