Polyamines in marine macroalgae:: Levels of putrescine, spermidine and spermine in the thalli and changes in their concentration during glycerol-induced cell growth in vitro

The levels of putrescine (Put), spermidine (Spd) and spermine (Spm) were analyzed in naturally collected samples of the marine macroalgae Dyctiota dichotoma Gelidium canariensis and Grateloupia doryphora. Polyamines (PAs) appeared in free (35-134 mug g(-1) fresh weight) and bound TCA-insoluble form (1667-2624 mug g(-1) fresh weight). Axenic in vitro cultures of sporelings from G. doryphora were established in the medium containing glycerol. This medium promoted growth and morphogenesis and also increased the free and bound PA levels in the sporelings. Tracer experiments using 70 kBq [U-C-14]-glycerol showed significant quantities of radioactivity in Put, Spd and Spm after 20 h of incubation, The effects of glycerol on growth were inhibited by the ornithine decarboxylase (EC 4.1.1.17) inhibitor alpha -difluoromethylornithine (DFMO), The presence of DFMO in the incubation medium with [U-C-14]-glycerol also reduced the radioactivity in PAs.