Abstract
Natural Microcystis aeruginosa specimens collected mainly from Suwa and Kasumigaura lakes were examined for both the hemagglutinating activity for mammalian erythrocytes and the toxicity in mice. Sixteen out of the 18 samples examined showed a hemagglutinating activity for rabbit erythrocytes, ten for rat and four for mouse erythrocytes. Ten strains in culture, agglutinated rabbit erythrocytes. One of those strains (M228), showed a high toxicity in mice as well as high hemagglutinating activity regardless of the type of erythrocyte tested. The strain (M228) partially lost the hemagglutinating activity on heating, but did not lose lethal potency, suggesting nonidentity of the responsible substances. It was noted that nontoxic samples, either natural or cultured, showed a marked hemagglutinating activity to mammalian erythrocytes of specific species.
