A dopamine- and octopamine-sensitive adenylate cyclase in the nervous system of Octopus vulgaris.

1. Adenylate cyclase activity was assayed in the optic lobe of Octopus vulgaris. 2.

Role of dopamine and indolamine derivatives in the regulation of the sea urchin adenylate cyclase.

The adenylate cyclase of the sea urchin egg is stimulated by dopamine in the presence of GTP. The enzyme activity is strongly enhanced when Gpp (NH)p is substituted for GTP, or after cholera toxin treatment. Gramine, an indolamine derivative, brings about non-competitive inhibition of the dopamine-stimulated adenylate cyclase activity.

Catecholamine secretion and adenylate cyclase activation in sea urchin eggs.

The role of neurotransmitters in sea-urchin eggs was investigated by studying their effect on adenylate cyclase of the egg membrane. Maximal stimulation of enzyme activity occurs in the presence of dopamine and GTP. 5-hydroxytriptamine, 5-methoxytriptamine and acetylcholine have no effect on activity, despite a decrease in intracellular cAMP level in eggs treated with 5-hydroxytriptamine antagonists as previously reported (Renaud et al.

Bud induction in decapitated Hydra attenuata by 5-azacytidine: a morphological study.

The effect of 5-azacytidine (5-azaCR) on head regeneration and budding in hydra are reported. Hydra attenuata were exposed to various doses of 5-azaCR for 48 h and then decapitated and cultured. Head regeneration and bud formation were observed for 12 days after decapitation.

dCMP-aminohydrolase activity during early sea urchin development. An example of negative enzyme control during embryogenesis.

In sea urchin, unfertilized eggs have a very high level of dCMP-aminohydrolase (dCMPase) activity, which decreases gradually and at the pluteus stage it is only about a quarter of that found in the unfertilized egg. But in abnormal embryos and in disaggregated cells from embryos, no decrease in the dCMPase activity takes place. To understand the control mechanism involved in this enzyme activity during development, we have analyzed the effect of various drugs which interfere with information transfer, such as actinomycin C, puromycin, 5-azacytidine, 2-thio-uracil and p-fluoro-DL-phenylalanine on dCMPase activity in embryos of Paracentrotus lividus and Sphaerechinus granularis.