Occurrence of a Hemolytic Protein Toxin in Nematocysts of a Marine Benthic Hydroid, Halocordyle disticha (Goldfuss)
William R. Kem, Carina Östman

Although hemolytic protein toxins have been found in all the major cnidarian classes, none have been previously reported in athecate hydroids inhabiting the marine benthos. A hemolytic factor occuring in a Percoll-separated nematocyst fraction obtained from Halocordyle disticha is described. Several pieces of evidence indicate that it is a large protein of about 400,000 apparent molecular size. Hemolytic activity was destroyed by proteases and boiling, reduced by thiol and disulfide group reagents, two serine protease inhibitors, and by freezethawing. Certain protease inhibitors stabilized hemolytic activity, as did the presence of serum albumin. The time course of hemolysis indicates that it is non-enzymatically mediated. The inability of EDTA to inhibit the hemolysis, plus the inhibitory influence of toxin preincubation with an egg lecithin suspension, indicates lack of phospholipase A involvement. Since filiform tentacles and tissues protected by the perisarc were almost as hemolytic as the capitate tentacles, the hemolytic factors(s) cannot be confined to the large stenotele type nematocysts, which are not present in the filiform tentacles.

Keywords: Nematocyst, Toxin, Halycordyle, Pennaria, Erythrocyte, Hydrozoan, Protein.
Contents of this volume Sci. Mar. 56(2-3) : 193-203 Back PDF
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