Studies on proteinaceous toxins newly found in bivalves belonging to the genus Corbicula

1.将日本各地的日本蚬（Corbicula japonica）的水提取物静脉注射到小鼠体内时，其所有样本均具有毒性。至于毒性，没有性别和季节变化，但明显认识到局部变化。另外两种蚬（C.leana和C.sandai）也有毒性，但比C. japonica低得多。无论种属，内脏是无毒的，几个肌肉组织是有毒的，最高的毒性观察到的足肌肉的C.日本，虹吸C.leana和外套肌肉的C.三代。经疏水层析、凝胶过滤和离子交换FPLC纯化，得到日本蛤毒素为弱碱性蛋白，分子量为25，000，pI为7.7。小鼠<50>静脉注射LD_（11 μ g/kg）。该毒素具有溶血活性，但缺乏抗微生物活性。虽然得不到纯品，但在稳定性和分子量方面与龟鳖毒素相当。3.对上述耗时的龟鳖毒素纯化方法进行了改进。结果表明，该毒素的纯化仅需与绵羊红细胞膜结合和离子交换HPLC两个步骤。4.由于该毒素对热不稳定，口服无毒，对人体健康没有严重影响。它们具有科学重要性，因为它们是双壳类中蛋白质毒素的第一个例子。

1.All specimens of the brackishwater clam Corbicula japonica obtained from various places of Japan were toxic when their aqueous extracts were intravenously injected into mice. As to toxicity, there were no sexual and seasonal variations but a local variation was obviously recognized. Two other Corbicula species (C.leana and C.sandai) were also toxic, though at much lower levels than C.japonica. Irrespective of the species, viscera were non-toxic and several muscular tissues were toxic ; the highest toxicity was observed in foot muscle for C.japonica, siphon for C.leana and mantle muscle for C.sandai. No toxicity was detected in 12 species of bivalves other than Corbicula species.2.The C.japonica toxin was purified by hydrophobic chromatography, gel filtration and ion-exchange FPLC and shown to be a weakly basic protein with a molecular weight of 25,000 and a pI of 7.7. Its LD_<50> (intravenous injection into mice) was estimated to be 11 mug/kg. The toxin showed hemolytic activity but lacked anti-microbial activity. Although the toxins of C.leana and C.sandai could not be obtained in a pure form, they were comparable to that of C.japonica with respect to stability and molecular weight.3.An attempt was made to improve the time-consuming purification method for the C.japonica toxin described above. As a result, the toxin was purified by only two steps comprising the binding to sheep erythrocyte membranes and ion-exchange FPLC.4.The Corbicula toxins evoke no serious problem to the human health, since they are very unstable to heating and non-toxic upon oral administration. They are of scientific importance in that they are the first examples of proteinaceous toxins from bivalves.