Biochemical studies on proteinaceous toxins in the skin mucus and roe of the lamprey Lampetra japonica

1.在七鳃鳗皮肤粘液和鱼卵中发现了新的植物毒素。一克皮肤粘液和一克卵对体重为20g的小鼠的杀伤力分别为70只和215-800只。两种毒素均无血凝和溶血活性；鱼卵毒素也缺乏抗菌活性。粘液毒素非常不稳定，因此没有实现纯化。通过CM-纤维素和羟基磷灰石的柱层析和Monos S的FPLC柱层析，纯化得到的鱼卵毒素具有较高的毒力。给小鼠注射，LD_(50)为33微克/公斤。该毒素为碱性毒素，在无2-聚环己烷存在的情况下，经SDS-PAGE测定其相对分子质量为4万，在还原试剂存在下，经SDS-PAGE分析表明，该毒素由分子量为3万和10000两种亚基组成。氨基酸组成以含硫氨基酸(半胱氨酸和蛋氨酸)含量低为特征。在被检查的21种鱼中，没有一种在它们的鱼卵中含有毒素。相比之下，在54种鱼中，有多达9种被发现皮肤粘液中含有毒素。3种鳗鱼毒素均为酸性蛋白质，相对分子质量约为40万，具有较强的毒性。它们在免疫学上也具有可比性。值得注意的是，鞘氨醇和神经节苷脂对日本按蚊和鳗鱼毒素的致死活性有抑制作用。

1. Plroteinaceous toxins were newly found in the skin mucus and roe of the lamprey Lampetra japonica. One gram of the skin mucus and roe was evaluated to kill 70 and 215-800 mice with a body weight of 20g, respectively. Both toxins showed no hemagglutinating and hemolytic activities ; the roe toxin also lacked antimicrobial activity.2. The mucus toxin was very unstable and hence its purification was not achieved. On the other hand, the roe toxin was purified to an electrophoretically pure state by column chromatography on CM-cellulose and hydroxyapatite and FPLC on Mono S.The purified toxin exhibited high lethal activity upon i.v. injection into mice ; the LD_<50> was estimated to be 33 mug/kg. It was basic in nature and its molecular weight was determined to be 40,000 by SDS-PAGE in the absence of 2-mer captocthanal, Analysis by SDS-PAGE in the presence of the reducing reagent revealed that the toxin was comprised of two kinds of subunits with molecular weights of 30,000 and 10,000. The amino acid composition was characterized by low contents of sulfur-containing amino acids (half-Cys and Met).3. None of the 21 species of fish examined had toxins in their roes. in contrast, as many as 9 of 54 species of fish were found to contain toxins in the skin mucus. Toxins in 3 species of anguillid fish (Anguilla japonica, Anguilla anguilla and Muraenesox cinereus), which were highly toxic, were all acidic proteins with a molecular weight of about 400,000. They were also immunologically comparable to one another. It was noticeable that sphingosine and gangliosides showed inhibitory effects on the lethal activity of the A.japonica and A.anguilla toxins.