镉和铜对海洋浮游植物的毒性效应及其机制研究进展

【目的】综述重金属元素镉Cd和铜Cu对海洋浮游植物的毒性效应研究,总结重金属对海洋浮游植物的毒性作用机制,为开展重金属对海洋浮游植物毒害机理的深入研究提供借鉴。【方法】以毒理实验中常用的重金属镉和铜为代表,总结了重金属对海洋浮游植物毒理研究的常用测试指标,归纳了重金属对海洋浮游植物光合作用、抗氧化系统等方面的毒性作用机制。【结果】重金属对海洋浮游植物毒性作用机制概括为:1)重金属替换与其结构相似的作为酶辅助因子的金属元素,使浮游植物体内某些酶失活;2)重金属直接或间接诱导活性氧的产生,使浮游植物受到氧化胁迫;3)重金属与生物大分子中的某些基团亲和性高而结合,阻断相关的生理生化过程。【结论】重金属的毒性效应因浮游植物种类不同而有所差异,今后相关研究中需更加关注重金属在多种海洋浮游植物共存环境下的毒性效应及机制,将有助于全面系统地理解重金属对海洋浮游植物的致毒机理。

Review of the Toxicological Effects and Mechanisms of Cadmium and Copper on Marine Phytoplankton

【Objective】To summarize the toxicological effects and mechanisms of heavy metals(cadmium and copper)on marine phytoplankton,and provide a reference for building a comprehensive toxicity profile and deciphering the mechanisms of toxicity.【Method】The existing literature related to the biological effects of heavy metals on microalgae was reviewed,as well as the current understanding of the mechanisms of toxic effects on photosynthesis and antioxidant system of marine phytoplankton.【Results】The toxicity effects and mechanisms of copper(Cu²⁺)and cadmium(Cd²⁺)on marine phytoplankton were summarized as follows:1)replacement of structurally similar metal ions which act as cofactors in enzymes and proteins,leading to inactivation of enzymes and abnormal metabolic activities in algae,2)direct or indirect ROS generation,reduced glutathione(GSH)depletion,and inhibition of the activity of antioxidant defense enzymes resulting in oxidative stress,and(3)affinity with thiol-,imidazole-,and carboxyl-groups of amino acid leading to protein inactivation and therefore to interrupt essential biological process.【Conclusion】Investigations on the effects of combined toxicity considering the interactions among co-existing aquatic species is potentially useful to provide further information to comprehensively and systematically understand the toxic mechanism of heavy metals to marine phytoplankton.