Variety of PSP toxin profiles in various culture strains of Alexandrium tamarense and change of toxin profile in natural A-tamarense population

Paralytic shellfish poisoning (PSP) toxin profiles were compared between clonal and axenic culture strains of Alexandrium tamarense prepared from cysts. The cysts were collected from two stations in northern Japan. The major toxin components of A. tamarense were C2 and GTX4, however, the proportions of C2 and GTX4 varied largely 0.7-78.8 mol% and 79.4-8.5 mol%, respectively. Some culture strains contained significantly higher proportion of neoSTX than other strains. These results indicate that strains with various toxin profiles exist in the same region, and suggest that the comparison of the toxin profiles between strains at different localities is considerably difficult. A drastic change of the toxin profile was observed in natural plant-tonic populations containing A. tamarense. This may be explained by the presence of a lot of plank-tonic populations with various toxin profiles growing around the sea area. (C) 2002 Elsevier Science B.V. All rights reserved.