Carotenoids of the Florida red tide dinoflagellate Karenia brevis

The red tide dinoflagellate Karenia brevis, formerly Gymnodinium breve, contained fucoxanthin, 19'-butanoyloxyfucoxanthin and 19'-hexanoyloxyfucoxanthin as carotenoid chemotaxonomic markers. In addition to beta,epsilon-carotene, beta,beta-carotene, diatoxanthin, diadinoxanthin and 19-hexanoyloxyparacentrone 3-acetate, the diester of gyroxanthin was also present. Pigment identities were established by both chromatographic (TLC and HPLC) and spectrometric (UV-vis, MS) methods, for the fucoxanthins also (1)H NMR was applied. The similarity in carotenoid pigmentation between the three ichthyotoxic dinoflagellates K. brevis, Karenia mikimotoi and Karlodinium micrum is pointed out. In terms of the endosymbiont theory the carotenoid pigmentation supports the hypothesis that these three species may have acquired their chloroplasts from a prymnesiophycean endosymbiont. (C) 2003 Elsevier Science Ltd. All rights reserved.