镉胁迫对虾夷扇贝抗氧化防御系统的影响

实验研究了虾夷扇贝在96 h的急性毒性效应,以及不同浓度Cd2+(0,0.005,0.025,0.050,0.150和0.300 mg/L)对虾夷扇贝内脏团超氧化物岐化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽-过氧化物酶(GSH-PX)活力的影响,以探讨其用于污染暴露的生物标记的可行性。结果表明:虾夷扇贝96 h的LC50为1.73 mg/L;其95%的置信区间是1.58～1.90 mg/L;安全浓度为0.0173 mg/L。酶活力:0.025 mg/L及以上的各实验组SOD活力先上升后下降,在第3 d时达到峰值,与对照组呈显著差异(P<0.05);处理第6 d,各浓度组SOD活力有所下降,到第9 d时受到抑制;CAT活力在处理0.5 d时,0.025mg/L0、.150 mg/L和0.300 mg/L三个浓度组均受到显著诱导(P<0.05),处理第6 d时,各实验组酶活力开始受到抑制。两种酶对实验设计的Cd2+浓度反应敏感,呈现出"诱导-抑制"规律,对海洋Cd2+早期污染具有指示作用。GSH-PX对Cd2+污染没有SOD和CAT那样敏感,GSH-PX的各个实验组与对照组相比差异均不显著,因而它作为对海洋Cd2+早期污染指示物的意义不大。

Effects of cadmium stress on antioxidant defense system of Patinopecten yessoensis

The experiment of the acute toxic effects of Patinopecten yessoensis in 96 h and the effects of cadmium(Cd) at different concentrations on superoxide dismutase(SOD),Catalase(CAT) and Glutathione peroxidase(GSH-PX)activity in P.yessoensis visceral tissue was carried out.It showed Cd2+ toxic effects on this marine fish.The results showed that P.yessoensis’s LC50 in 96 h was 1.73 mg/L,95% confidence interval was 1.58~1.90 mg/L,and the safe concentration was 0.0173 mg/L.The SOD activity of 0.025 mg/L and above all of groups was increased at first and then decreased.The maximum and minimum values appeared on 3th day,and showed the significant difference with the control group(P<0.05).The SOD activity in each group was decreased on 6th day and was restrained on 9th day.The CAT activity of 0.025 mg/L,0.150 mg/L and 0.300 mg/L showed the significant difference with the control group(P<0.05)on 0.5th day.The CAT activity of each group was restrained on 6th day.The SOD and CAT activity of Patinopecten yessoensis visceral tissue was sensitive to Cd2+,presenting inhibit-inducement rule,which had biological indicative function for the water environmental Cd2+ early pollution.The GSH-PX activity was less sensitive to Cd2+ than SOD and CAT activity.Compared with the control group,there was not group showing the significant difference.So there was not point in accepting GSH-PX as the indicator of water environmental Cd2+early pollution.