Hemolytic activity and fatty acids composition in the ichthyotoxic dinoflagellate Cochlodinium polykrikoides isolated from Bahía de La Paz, Gulf of California.

The hemolytic activity of the dinoflagellate Cochlodinium polykrikoides from Bahía de La Paz, Gulf of California was investigated as part of the ichthyotoxic mechanism of this microalga. Two different kinds of erythrocytes, fish and human, were tested for the hemolytic assay. Since fatty acids have been associated with hemolytic activity in C. polykrikoides, the composition of fatty acids of this dinoflagellate was also analyzed. The concentration of C. polykrikoides causing 50% hemolysis (HE(50)) was 4.88 and 5.27x10(6) cellsL(-1), for fish and human erythrocytes, respectively. According to the standard curve of saponin, an equivalence between the hemolytic activity of saponin and the dinoflagellate concentration was found with 1mug saponinmL(-1) equivalent to 1x10(6) cellsL(-1) of C. polykrikoides. The polyunsaturated fatty acids: hexadecaenoic (16:0), docosahexaenoic (22:6 n3) and octadecapentaenoic (18:5 n3) were found in an abundance of approximately 62% of total fatty acids.