A toxicological study of the marine phytoflagellate, Chattonella antiqua (Raphidophyceae)

The toxin composition and ichthyotoxicity of the phytoflagellate Chattonella antiqua (Hada) Ono (Raphidophyceae) were investigated during various stages of growth in unialgal culture. Three neurotoxic components, CaTx-I, CaTx-II, and CaTx-III, which corresponded to brevetoxin components PbTx-2, PbTx-3, and oxidized PbTx-2, were inferred from analysis of C. antiqua toxins on TLC and HPLC. The yield of CaTx-III was highest among the toxins, ranging from 2.48 to 6.85 pg cell−1 in logarithmic or stationary phase cultures. The quantity of each toxin fluctuated according to the age and growth stage of the culture. During the growth cycle there was a significant change in the concentration of CaTx-II and CaTx-III. In the early logarithmic phase, the amount of CaTx-II was highest (1.69 pg cell−1) and that of CaTx-III was lowest (2.48 pg cell−1). As the culture entered stationary phase, the amount of CaTx-II declined sharply (from 0.70 to 0.20 pg cell−1) whereas a rapid increase occurred in CaTx-III (from 3.98 to 6.85 pg cell−1). In ichthyotoxicity studies, C. antiqua showed high toxicity during early to mid-logarithmic growth when most of the cells were motile and spindlelike. After reaching the stationary phase, the toxicity decreased markedly and the number of oval-or spherical-shaped and nonmotile cells increased.