1982 Volume 48 Issue 4 Pages 567-571
Protogonyaulax cells collected from Ofunato Bay were fractionated into “20-30”, “30-40”, and “40-95” μm fractions by sieves having mesh sizes of 20, 30, 40 and 95 μm. In the case of P. tamarensis, the toxicity was 0.54-1.46 MU/104 cells for the “20-30” μm fraction, 1.14-2.43 MU/104 cells for the “30-40” μm fraction, and 1.14-2.25 MU/104 cells for the “40-95” μm fraction. Microscopic observations showed that most cells of the “20-30” μm fraction were over younger ones equipped with soft theca or cell membranes. Similar attempts were made to separate P. catenella cells into three fractions, but their toxicities were too low to be assayed.
