Hemolytic and toxic properties of Hydra attenuata nematocysts.

Crude extract prepared from isolated and purified nematocysts (stenoteles, desmonemes, isorhizas) of Hydra attenuata Pall. (Cnidaria, Hydrozoa) contains two main toxic proteins. The first is a hemolysin (100-200,000 mol.wt) which also causes initial spasmodic contractions in larval and adult specimens of Drosophila. Both, hemolytic and neurotoxic activities are inhibited by low concentrations of Triton X-100. The second protein (30-100,000 mol.wt), which is not susceptible to Triton causes long lasting paralysis leading to death of the test animals (LD50 approximately 5 mg crude nematocyst extract per kg). Neither of the toxins is identical with the previously described phospholipase.