Isolation and characterization of a lethal hemolysin in the sea anemone Parasicyonis actinostoloides

Four species of sea anemones in the coastal waters of Japan were surveyed for hemolysins. Powerful hemolysins were detected in Parasicyonis actinostoloides and Anthopleura japonica, whereas extracts of A. fuscoviridis showed much weaker hemolytic activity and those of of Haliplanella luciae no activity. Among the animal erythrocytes tested sheep were most sensitive to the hemolysins of the three positive species. The major hemolysin (parasitoxin) in whole bodies of P. actinostoloides was isolated by ion exchange chromatography, gel filtration and chromatofocusing. In addition to hemolytic activity (119900 HU/mg) it exhibited lethal activity in mice (LD50 65 micrograms/kg, i.v.) and fish Oryzias latipes (approximate minimum lethal concentration 1.5 micrograms/ml). Parasitoxin was slightly basic (pI 7.9) in nature and its amino acid composition was characterized by the absence of half-cystine. The molecular weight was 19,000 by SDS-polyacrylamide gel electrophoresis or 17,000 by sedimentation equilibrium, indicating that parasitoxin has no subunit structure.