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.     

Die biosynthetische Inkorporation von externem S35O2 in Glucobrassicin

Summary In plants of theBrassica oleracea species contaminated with S³⁶O₂, incorporation of radioactive sulphur into glucosinolate glucobrassicin has been found. The label is present also in the isothiocyanate group of glucobrassicin, which by decomposition under the action of myrosinase liberates labelled thiocyanate.     

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.     

Aberrant,canavanyl protein formation and the ability to tolerate or utilize L-canavanine

Summary L-Canavanine, 2-amino-4-(guanidinooxy)butyric acid, and L-arginine incorporation into de novo synthesized proteins was compared in six organisms. Utilizing L-[guanidinooxy¹⁴C]canavanine and L-[guanidino¹⁴C]arginine at substrate saturation, the canavanine to arginine incorporation ratio was determined in de, novo synthesized proteins.Caryedes brasiliensis andSternechus tuberculatus, canavanine utilizing insects;Canavalia ensiformis, a canavanine storing plant; and to a lesser extentHeliothis virescens, a canavanine resistant insect, failed to accumulate significant canavanyl proteins. By contrast,Manduca sexta, a canavanine-sensitive insect, andGlycine max, a canavanine free plant, readily incorporated canavanine into newly synthesized proteins. This study supports the contention that the incorporation of canavanine into proteins in place of arginine contributes significantly to canavanine's antimetabolic properties.     

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.     

Über den Einbau14C-markierter Aminosäuren in Zellkernfraktionen aus Meerschweinchenleberzellenin vitro

Summary The incorporation of¹⁴C-amino acids into ribonucleoproteid particles obtained by differential centrifugation of mechanically disintegrated liver cell nuclei was demonstratedin vitro. Nuclear supernatant revealed also very remarkable incorporation.     

Etude autoradiographique de l'incorporation de la thymidine-3H,de l'uridine-3H et de la phénylalanine-3H dans les chloroplastes deClivia miniata etBilbergia sp.

Summary Mature chloroplasts ofClivia miniata etBilbergia sp. show the intensive incorporation of thymidine³H into DNA and uridine³H into RNA. On the contrary, phenylalanine³H is mostly incorporated in the proplastids.     

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.     

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.     

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.     

Untersuchungen über den Wirkungsmechanismus von Procarbazin (Natulan®)

Summary The cytotoxic methylhydrazine derivative procarbazine or Natulan® has a marked influence on the synthesis of deoxyribonucleic acid in Ehrlich ascites carcinoma cells. The incorporation of³H-thymidine into DNA — measured by autoradiographic methods — is inhibited.     

Influence of cyclic nucleotides on protein synthesis in vascular smooth muscle

Summary The incorporation of leucice-¹⁴C into protein in bovine mesenteric arteries was augmented by cyclic GMP (10^–3 M) and decreased by cyclic AMP (10^–3 M). There was no effect of 5 AMP (10^–3 M). The phosphodiesterase inhibiting drugs theophylline (10^–3 M) and papaverine (5×10^–5 g/ml) both decreased the leucine-¹⁴C incorporation.We are indebted to Mrs.Lena Burlin for hear assistance. Finacial support has been provided by the Swedish State Medical Research Council (No. 04X-101X-4498).     

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.     

Abbauprodukte von Simazin in Gramineen

Summary Coix lacryma-jobi L., about 20 days old and grown on watercultures, were fed with¹⁴C-ring-labelled simazine. After freeze drying, the plant tissue was extracted with chloroform and 80% ethanol. The ethanol extractable activities were fractionated on a cation exchange column. The radioactive metabolites seem to be identical with 2-hydroxy-4, 6-diethylamino-s-triazine (hydroxysimazine), 2-hydroxy-4, 6-diamino-s-triazine (ammelin) and 2-hydroxy-4-ethylamino-6-amino-s-triazine.     

Zur Biosynthese des Verbenalins und Aucubins

Summary Verbena officinalis specifically incorporates 2-¹⁴C labelled mevalonic acid in the formation of the aglycone moiety of verbenalin (2). In aucubin (6), isolated fromVerbascum thapsus, the incorporation rate is very low and the main part of the activity is located in the sugar moiety.     

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.     

Zur Biosynthese der C9–10-Einheit der Indolalkaloide

Summary After administration of various C₂-compounds as well as leucine-2-¹⁴C toCatharanthus roseus shoots and glycine-2-¹⁴C toStrychnos nux vomica plants no specific incorporation into the non-tryptophan C_9–10 moiety of indole alkaloids was observed. The results indicate that glycine-2-¹⁴C is transformed into serine and is incorporated via tryptophan into strychnine.     

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.     

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.