微囊藻毒素在铜锈环棱螺肝组织中的累积降解及对3种酶活性的影响

把铜锈环棱螺（Bellamya aeruginosa）暴露于不同浓度的有毒微囊藻藻液中（对照组：只投喂四尾栅藻（Scenedes musquadricanda）；混合藻组：50％四尾栅藻＋50％铜绿微囊藻（Microcystis aerugirtosa）；蓝藻组：只投喂铜绿微囊藻），用酶联免疫检测法（Enzyme—linked immuno sorbentassay，ELISA）检测藻液和肝组织中藻毒素浓度，藻液中包括藻相和水相的总微囊藻毒素（MC）浓度分别为：对照组0ug·L^-1；混合藻组（14．47±1．22）ug·L^-1；蓝藻组（29．47±2．43）ug·L^-1。螺在两种不同毒素浓度藻液中暴露15d后再移人四尾栅藻藻液中降解15d。结果表明，暴露期间，混合藻组、蓝藻组螺肝组织中MC含量均为先增加后减少，再增加，且同期混合藻组MC含量都明显高于蓝藻组；作为机体代谢生物标志物的酸性磷酸酶（ACP）和碱性磷酸酶（ALP）活性随MC浓度及其暴露时间发生相应变化；作为解毒生物标志物的谷胱甘肽硫转移酶（GST）活性在混合藻组先被诱导后被抑制，在蓝藻组初期变化不明显后表现为诱导。在15d降解过程中，混合藻组和蓝藻组MC含量均持续下降；机体生物标志物ACP、AIJP和GST活性表现为不同程度的降低。本试验结果为ACP、ALP和GST活性作为MC胁迫的生物标志物提供了一些依据。

Accumulation and Degradation of Microcystins and Their Effects on Activities of Three Kinds of Enzymes in Liver of Bellamya Aeruginosa

A species of freshwater snail （Bellamya aeruginosa） was exposed to different concentrations of microcystins （MC） with the control group fed only by Scenedesmus quadricauda, the mixed group fed by 50% S. quadricanda ＋ 50% Microcystis aeruginosa, and the blue-algae group fed by only M.aeruginosa. Concentration of MC in the culture solution and the hepatic tissue of the snails was measured using the En zyme-linked immuno-sorbent assay （ELISA）. The average concentration of MC in the control, the mixed and the blue-algal group was 0, （14.47±1.22） and （29.47±2.43）ug·L^-1. After 15-day＇s exposure, B. aeruginosa was transferred to S. quadricanda culture for MC degrada- tion with a 15-day duration. The MC content in the liver ofB. aeruginosa in both experimental groups （the mixed and the blue-algal group） all increased initially, then decreased, and increased again during the exposure period. The content of MC was significantly higher in the mixed group than that in the blue-algal group. The activities of acid phosphatases （ACP） and alkaline phosphatases （ALP） as biomarker enzymes changed in a time-dependent manner in response to MC concentration in the liver of B. aeruginosa. The activity of glutathione-S-transferase （GST） as a biomarker enzyme of detoxification was induced initially and then inhibited in the mixed group during the exposure period. Initial activity of GST in the blue-algal group did not change significantly, but increased remarkably at the late stage of the exposure. A gradual yet incomplete elimination of MC content was observed during the degradation period. And these enzymatic activities all decreased during the course of degradation. These changes were very prominent in the livers. The changes in ACP, ALP and GST activities in the experiment suggest that these enzymes were actively involved in the detoxification process in B. aeruginosa tissue contaminated with MC. The results of this experiment demonstrated that the activities of ACP.ALP and GST may be used