Identity between cytolysins purified from two morphos of the Caribbean sea anemone Stichodactyla helianthus

Stichodactyla helianthus is a sea anemone relatively abundant along Cuban coasts appearing in two morphos with different colors in their tentacles: green or brownish, probably due to their association with algal symbionts. Traditionally, the brownish morpho has been used as a source of sticholysins I and II, the most characterized cytolysins from this anemone, but the green morpho is the most abundant along the western coasts of Havana. The present work is aimed to establish if the cytolysins purified from the green morpho (StIg and StIIg) are similar to those purified from brownish anemones (StI and StII). Following the same chromatographic procedure used to purify the toxins from morphos, the electrophoretic mobilities, amino acid compositions, amino terminal sequences and molecular masses were practically identical between analogal cytolysins. In conclusion, homologous sticholysins purified from the green and brownish variants of Stichodactyla helianthus are the same molecular entities.