马拉硫磷对双齿围沙蚕乙酰胆碱酯酶和过氧化氢酶的影响

Effection of Malathion on the Activity of Acetycholinesterase and Catalase of Polychaete Perinereis aibuhitensis

采用浓度梯度污染暴露室内模拟方法,研究了沙蚕暴露于不同浓度有机磷农药马拉硫磷的急性毒性效应,以及低浓度马拉硫磷对双齿围沙蚕乙酰胆碱酯酶(AChE)和过氧化氢酶(CAT)的影响。结果表明,马拉硫磷对沙蚕48、72、96h的LC50分别为71.68、49.21、33.16mg·L-1,安全浓度为3.32mg·L-1。在低浓度(0.0018～9mg·L-1)马拉硫磷中暴露3和6d,沙蚕体内乙酰胆碱酯酶活性受到显著抑制,暴露6d时9mg·L-1浓度组最高抑制率达88.92%,且乙酰胆碱酯酶抑制率与马拉硫磷浓度对数具有显著的剂量效应。沙蚕CAT活性随马拉硫磷浓度增加表现出先降后升再降的趋势,暴露3d时0.018mg·L-1浓度组CAT活性最高,6d时0.18mg·L-1浓度组CAT活性最高,分别比对照组高52.02%和53.42%(P<0.05),而浓度达1.8mg·L-1时CAT活力均显著下降(P<0.05)。结果显示,沙蚕乙酰胆碱酯酶是较好的滩涂有机磷农药污染生物标记物。

Polychaete Perinereis aibuhitensis is considered to be a key species in estuarine ecosystem,and has proved to be a sentinel organism for pollution stress. In order to test the possiblity of Perinereis aibuhitensis acting as an indicator organism to organophosphorus pesticide malathion pollution, we conducted the experiment to determine the acute toxic effects of various concentrations of malathion on the P. aibuhitensis, and to examine the change pattern of their acetycholinesterase（AChE）activity and catalase（CAT）activity after exposed to low concentration of malathion. The results indicated that the malathion had a strong toxic effect on P. aibuhitensis. The 48 h, 72 h, 96 h LC50 values of P. aibuhitensis were 71.68, 49.21, 33.16 mg·L^-1, respectively, and the safety concentration was 3.32 mg·L^-1. The AChE activity of the P. aibuhitensis was significantly inhibited by the malathion, with the maximum inhibition of 88.92% which appeared at 9 mg·L^-1 on 6 d. Moreover, the inhibition of AChE significantly corelated with the malathion concentration. Malathion treatment led to an initial decline in CAT activity followed by a sharp increase and then declined again. These results showed that the AChE activity of P. aibuhitensis could be used as a good biomarkers to malathion pollution in coastal beach.