理化因子对多变鱼腥藻溶血素活性的影响

Effects of physical and chemical factors on the hemolysis of the Anabaena variabilis hemolysin

采用对兔血红细胞的溶血实验，测定和分析了多变鱼腥藻（Anabaena variabilis OL S1）培养液在不同生长时期的溶血活性以及温度、pH和金属离子等理化因子对其溶血素活性的影响。钴果表明，任对数生长中期多变鱼腥藻开始向胞外分泌活性较高的溶血性毒素，在稳定期溶血活性达到最高。4℃低温几乎完全抑制了溶血素活性；在溶血反应最初的30min内，溶血活性随着温度的升高而迅速增强；但在反应持续60min后，16-37℃温度下溶血素活性趋于一致；溶血素在偏酸性条件下活性较高，而pH为7．2-9．0时活性无明显差异；Mg^2＋、Ca^2＋能显著增加其溶血活性，Cu^2＋、Mn^2＋则显著抑制其活性，Ge^2＋、Fe^3＋、Zn^2＋对其影响不大。红细胞膜组分腰固醇、鞘磷脂和卵磷脂均能竞争性结合溶血素，显著抑制溶血反成，因此可能是溶血素在红细胞膜上的作用受体。

The present paper aims at reporting the authors＇ research on the ways to determine the hemolytic activities of 20-fold concentrated cell-free supernatants of Anabaena variabilis OL SI and the effects of some physical and chemical factors on the bemolytic activities by taking the hemolysis of rabbit erythrocytes as an assay. The results show that a hemolytic activity may come about in the cultured medium at the mid-exponential growth phase, gradually intensifying itself with the cell growth, and, then, getting to its maximum size at the stationary phase, which suggests that the hemolytic toxin has been secreted actively into the medium by A. variabilis cells, rather than simply leaking from the rnptured dead cells. The above depicted process also implies that the hemolytic activity of A. variabilis OL SI is affected significantly by temperature, pH and various metal ions. For example, lower temperature （4 ℃ ） wouht ahnost make the hemolytic activity totally inhibited during the entire 300 rain reaction period. Though the hemolytic activities can be enhanced quickly with the increase of temperature from 16 ℃ to 37 ℃ during the first 30 min, they may reach a similar value in 60 min. Moreover, the activity would be intensified in the acid condition （pH 5.0- 6.0）, and then presents itself little difference in pH 7.2 - 9.0, thus implying that higher concentration of H ^＋ helps to facilitate the hemolytic activities. In addition, supplementary metal ions of 4.76 mmol·L^- 1 Mg^2＋ Ca^2＋ also helps to increase the hemolytic activity, though 4.76 retool·L^-1 Cu^2＋ Mn^2＋ may decrease it significantly. However, 4.76 mmol·L^-1 Ge^2＋ , Fe^3＋ , Zn^2＋ suggest little effect on it. And, finally, adding 7.62 mg·L^-1 cholesterol, sphingomyelin and lecithin may distinctively inhibit the hemolysis of A. variabilis hemolytic toxin, thus indicating it is possible to make it combined competitively with the hemolysin, acting as potential receptors of the hemolysin on tire erythrocyte membrane.