Polyamine biosynthesis and accumulation during the early development of the nudibranch Phestilla sibogae

Abstract

Polyamine biosynthesis and accumulation were studied during the early development of the nudibranch Phestilla sibogae. Ornithine decarboxylase activity increases over 40-fold in the first 4 days of embryogenesis, with the maximum (400 pmole of 14CO 2/30 min/mg of protein) occurring between Days 3 and 4, the time of most rapid growth. Putrescine-stimulated S-adenosyl- l-methionine decarboxylase activity is not detectable until the second day of development and attains maximal activity (100 pmole of 14CO 2/30 min/mg of protein) at Day 4. The pattern of spermidine-stimulated S-adenosyl- l-methionine decarboxylase activity is similar. Putrescine and spermidine double in concentration between Days 0 and 6. Adults contain fairly high levels of putrescine and spermidine, similar to prokaryotes. The increase in the polyamine biosynthetic enzymes and the accumulation patterns of the polyamines correlate well with data from other early developmental systems and support the hypothesis of key roles for the polyamine pathway in the control of growth processes.