1998 Volume 56 Issue 8 Pages 651-660
Marine micro-algae distribute widely in marine environments and display various interesting biological phenomena such as bioluminescence, red-tide forming, sea-food poisoning through food-chain mechanism and/or specific bio-accumulation, and symbiosis with invertebrates. In a course of our studies on biological origin of paltoxins, well known marine toxins from zoanthid, we have isolated new metabolites from a symbiotic dinoflagellate, Symbiodinium sp., collected from a flat worm and cultured under two different conditions. Structural similarities between zooxanthellatoxins, major metabolites in ES medium, and palytoxins suggested that there exist common biogenetic processes such as polyketide pathway utilizing a glycine starting unit and tetrahydropyrane ring formation. Zooxanthellamine, a major metabolite in f/2 medium, was shown to be structurally related to zoanthid alkaloids, zoanthamines, suggesting algal origin of zoanthamines. Biogenesis of gonyauline, an endogenous period-shortening substance from Gonyaulax polyedra revealed a common metabolic pathway of methionine (methionine cascade) in dinoflagellates. Wide distribution of bioluminescent compounds among marine organisms suggested the presence of unknown processes including specific bio-accumulation and common biogenesis.
