An assay for dopamine-β-hydroxylase activity in tissues and serum

Zusammenfassung Eine isotopische Methode zur Bestimmung der DH-Aktivität wird beschrieben. Die Methode wurde verwendet zur Bestimmung der DH-Aktivität im menschlichen Serum und in verschiedenen Organen der Ratte. Das sympatische Nervensystem des Menschens kann mit dieser Methode weiter erforscht werden.

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This work was supported by USPHS Grant No. 5 R01 MH-02717-12.     

Role of intracellular symbionts in the fatbody of cockroaches: Influence on hemolymph proteins

Zusammenfassung Zur Herabsetzung der Anzahl von Symbionten in einem Fettkörper der KüchnschabeBlaberus craniifer wurde eine Penicillin-G-Behandlung durchgeführt, was eine Reduktion bei 2 Hämolymphe-Proteinen verursachte. Diese mit der Symbionten-Aktivität und Fortpflanzung verknüpften Proteine treten am Ende der Behandlung wieder in Erscheinung.     

Competence to replicate in the unfertilized egg is conferred by Cdc6 during meiotic maturation

Meiotic maturation, the final step of oogenesis, is a crucial stage of development in which an immature oocyte becomes a fertilizable egg. In Xenopus, the ability to replicate DNA is acquired during maturation at breakdown of the nuclear envelope by translation of a DNA synthesis inducer that is not present in the oocyte. Here we identify Cdc6, which is essential for recruiting the minichromosome maintenance (MCM) helicase to the pre-replication complex, as this inducer of DNA synthesis. We show that maternal cdc6 mRNA but not protein is stored in the oocyte. Cdc6 protein is synthesized during maturation, but this process can be blocked by degrading the maternal cdc6 mRNA by oligonucleotide antisense injections or by translation inhibition. Rescue experiments using recombinant Cdc6 protein show that Cdc6 is the only missing replication factor whose translation is necessary and sufficient to confer DNA replication competence to the egg before fertilization. The licence to replicate is given by Cdc6 at the end of meiosis I, but the cytostatic factor (CSF) pathway, which maintains large amounts of active Cdc2/Cyclin B2, prevents the entry into S phase until fertilization.