Abstract:

Objective To investigate the effects of several metallic ions on the activity of phenoloxidase (PO) from Oncomelania hupensis of different ages such as adult snails, young snails, and snail eggs. Methods PO from O. hupensis of different ages was partially purified. PO activity was determined with different concentrations of NaCl, KCl, Na2SO4, K2SO4, MgSO4, CaSO4, ZnSO4, and CuSO4. Catechol was used as a substrate. Results Na+ and K+ had no effects on the activity of PO from O. hupensis of any age. Mg2+ and Ca2+ showed enhancing effects in all age groups, while Zn2+ had an inhibitory effect. For O. hupensis of different ages, Cu2+ enhanced the enzyme activity at low concentrations, but inhibited the enzyme activity at high concentrations. Conclusion Several metallic ions such as Mg2+, Ca2+, Zn2+, and Cu2+ can affect the activity of PO from O. hupensis of different ages. These findings provide a rationale for developing novel methods in chemically eliminating snails.

Key words: Oncomelania hupensis, Phenoloxidase, Metallic ion, Enzyme activity

摘要：

目的 探讨金属离子对不同螺龄湖北钉螺(成螺、幼螺、螺卵)酚氧化酶(PO)活性的影响。方法 将不同螺龄湖北钉螺软体制作成部分纯化的PO酶液。以邻苯二酚作为底物, 分别检测不同浓度NaCl、KCl、Na2SO4、K2SO4、MgSO4、CaSO4、ZnSO4及CuSO4等对PO活性的影响。结果 Na＋和 K＋对不同螺龄湖北钉螺PO活性均无影响;Mg2＋和Ca2＋对不同螺龄湖北钉螺PO活性均有激活效应;而Zn2＋对该酶均有抑制作用;低浓度Cu2＋可提高不同螺龄湖北钉螺PO活性, 而高浓度Cu2＋则可降低该酶活性。结论 Mg2＋、Ca2＋、Zn2＋及Cu2＋等金属离子均可影响不同螺龄湖北钉螺PO活性, 为化学灭螺新途径提供理论依据。

关键词: 湖北钉螺, 酚氧化酶, 金属离子, 酶活性