镉在虾夷扇贝的沉积及对GPx、GST的影响

为了解海洋重金属污染物镉(Cd)在虾夷扇贝体内鳃、消化腺组织中的沉积规律及对其抗氧化防御系统的影响,将虾夷扇贝置于不同Cd浓度污染的水环境中,观察其镉的累积及谷胱甘肽过氧化物酶(GPx)、谷胱甘肽硫转移酶(GST)的变化规律。结果显示,鳃、消化腺中最大Cd沉积分别出现在10d,0.2mg·L-1胁迫组(鳃,134.20μg·g-1)和14d,0.1mg·L-1胁迫组(消化腺,109.20μg·L-1),两组织Cd的浓度累积均随胁迫浓度的增加而升高;鳃、消化腺组织GSH-Px活性随胁迫浓度的升高、胁迫时间的延长均呈现先升高后降低的趋势,且后者GSH-Px活性显著高于前者;鳃、消化腺组织GST活性在胁迫浓度为中低浓度时(0.05mg·L-1、0.1mg·L-1),呈现先升高后下降趋势,但高浓度胁迫下(0.2mg·L-1),均在短时间内表现出明显的抑制。不同浓度的Cd随时间及胁迫浓度的增加可在虾夷扇贝体内出现明显累积,GPx、GST可作为虾夷扇贝Cd污染的生物标志物。

Cadmium Specific Accumulation and Its Effect on the Activity of GPx, GST in Mizuhopecten yessoensis

Japanese scallop(Mizuhopecten yessoensis) is the most important aquatic species in north of China.For the purpose of investigation the accumulation of cadmium(Cd) and the antioxidant defense system in gill and digestive gland,Japanese scallops were exposed to different doses of Cd for 14 days.Cd concentration and GPx,GST were assayed.The maximum of Cd accumulation in gill and digestive gland occurred in 10 d(134.20 μg·g-1) and 14 d(109.20 μg·g-1),respectively.Also,the increase of Cd accumulation accompanied with the higher doses of Cd.The activity of GPx in both tissues displayed curvilinear relationship with time of exposure in all Cd treatment groups.Moreover,the activity in digestive gland was significantly higher than that in gill.GST activities in both tissues also showed similar relationship with time of exposure in 0.0 5 mg·L-1 and 0.1 mg·L-1 Cd treatment groups.However,the activity of GST in 0.2 mg·L-1 group was significantly inhibited in short exposure time.In conclusion,Cd displayed significantly accumulation in gill and digestive gland of Japanese scallop and GPx,GST can be used as biomarkers in early warning Cd pollution.