Zooxanthellamide D, a polyhydroxy polyene amide from a marine dinoflagellate, and chemotaxonomic perspective of the Symbiodinium polyols.

A long-chain polyhydroxy polyene amide, zooxanthellamide D (ZAD-D, 1, C54H83NO19), was isolated from a cultured marine dinoflagellate of the genus Symbiodinium. ZAD-D (1) is a polyhydroxy amide consisting of a C22-acid part and a C32-amine part and furnishes three tetrahydropyran rings and six isolated butadiene chromophores. The relative stereochemistry of the tetrahydropyran ring systems was elucidated by NMR techniques. This metabolite showed moderate cytotoxicity against two human tumor cell lines. A phylogenetic tree of Symbiodinium has been updated and compared with the structures of the hitherto isolated polyols of Symbiodinium, zooxanthellatoxins and zooxanthellamides, providing a promising chemotaxonomic perspective for the classification of this morphologically indistinguishable dinoflagellate.

Identification of paralogous genes of firefly luciferase in the Japanese firefly, Luciola cruciata.

Two homologous genes of firefly luciferase, LcLL1 and LcLL2, were cloned from the Japanese firefly Luciola cruciata, and were expressed and characterized. The gene product of LcLL1 had long-chain fatty acyl-CoA synthetic activity, but not luciferase activity. The other gene product of LcLL2 did not show enzymatic activities of acyl-CoA synthetase and luciferase. RT-PCR analysis showed that the transcript of LcLL1 was abundant in larva but very low in adult, while LcLL2 was expressed in both larva and adult. Phylogenetic analysis indicated that LcLL1 and LcLL2 are paralogous genes of firefly luciferase. Recently, we found that CG6178 in Drosophila melanogaster is an orthologue of firefly luciferase and shows fatty acyl-CoA synthetic activity, but not luciferase activity. These results suggest that firefly luciferase might be evolved from a fatty acyl-CoA synthetase by gene duplication in insects.