66(P-49) ハワイ産立方クラゲCarybdea alataの刺胞毒の化学的性状(ポスター発表の部)

抄録

The box jellyfish (Sea Wasp) Carybdea alata Reynaud, 1830 (Cubozoa) is distributed widely in the tropics. The sting of C. alata causes severe pain and cutaneous inflammation in humans. We successfully isolated C. alata toxin-A (CaTX-A, 43kDa) and -B (CaTX-B, 45kDa) for the first time from the tentacle of C. alata collected at the Hawaiian shore. The experimental results showed that CaTX-A, but not CaTX-B, is present in the nematocyst, the organ responsible for stinging. Both CaTX-A and -B showed potent hemolytic activity. CaTX-A was lethally toxic to crayfishes with intraperitoneal injection. Furthermore, we sequenced the cDNA encoding CaTX-A. The deduced amino acid sequence of CaTX-A (463 amino acids) showed 43.7% homology to C. rastoni toxins (CrTXs) but not with any other known proteins. Therefore, these jellyfish toxins potentially represent a novel class of bioactive proteins. Secondary structure analysis of CaTX-A and CrTXs suggested the presence of amphiphilic ot-helices, which are also seen in several known hemolytic or cytolytic protein toxins, including peptide toxins.