Biosynthesis of animal and plant bufadienolides. Parallel experiments with pregn-5-en-3-ß-ol-20-one-20-14C inScilla maritima andBufo paracnemis

Zusammenfassung Pregnenolon-20-¹⁴C wird von roten Meerzwiebeln als Vorstufe für herzwirksame Glykoside verwendet, dagegen kannBufo paracnemis diese Produkte, subkutan appliziert, nicht in die üblichen Krötengifte überführen.     

New intermediates in phaeomelanogenesis in vitro

Riassunto Mediante esperimenti in vitro, è stato accertato che i primi stadi della biosintesi delle feomelanine conducono alla formazione di derivati diidrobenzotiazinici, ai quali sono state assegnate le strutture III e IV.

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This investigation was supported by a grant from the Laboratorio di Chimica e Fisica per lo Studio delle Molecole di Interesse Biologico del C.N.R., Napoli.     

Zur Wirkung von Oxytocin auf einen autorhythmischen glatten Gefässmuskel

Summary The influence of oxytocine on the spontaneously contractile portal vein of the rat has been investigated. This octapeptide decreases the active tension and abolished it completely at a concentration of 5×10^–7g/ml. The effect is not caused by an adrenergic mechanism but by a direct action on the smooth muscle cell.     

Etude de l'hemocyanine d'un Crustacé décapodeCarcinus maenas Linné par dichroïsme circulaire naturel et dichroïsme circulaire magnétique

Summary The hemocyanin ofCarcinus maenas L. in the oxy, deoxy and apoforms is examined by CD and MCD. An interpretation of the results is given in relation to the problems raised by Cu–O² bond. The ration tyrosin/tryptophan is determined by treatment of spectra by computer.