虾夷扇贝内脏团对镉的富集特性及生理响应

Cadmium Accumulation Characteristics and Physiological Response of Scallop Mizuhopecten yessoensis

【目的】对虾夷扇贝(Mizuhopectenyessoensis)内脏团中镉的富集特性进行研究,并分析镉暴露后与镉胁迫相关的基因在内脏团中的表达。【方法】采用人为添加镉的方法使虾夷扇贝进行镉暴露,原子吸收分光光度计测定各组织中镉含量,实时荧光定量PCR技术检测过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GPx)和热休克蛋白70(HSP70)基因在虾夷扇贝内脏团中的表达。【结果】虾夷扇贝内脏团比其他组织富集了更多的镉(P=0.004),在含400μg/L Cd海水中暴露7 d和10 d后,扇贝内脏团中的Cd质量分数由62μg/g(干基)分别增加到180和217μg/g(干基);内脏团中抗氧化酶CAT、SOD和GPx以及热休克蛋白HSP70在200μg/L Cd暴露7 d后的基因表达量也显著增加(P <0.05)。【结论】内脏团是虾夷扇贝富集镉的重要组织,内脏团中CAT、SOD、GPx和HSP70对扇贝镉的防御有重要作用。

【Objective】To study the cadmium accumulation characteristics of Mizuhopecten yessoensis and to investigate the expression of several genes related to cadmium stress in the digestive gland of scallop after cadmium exposure. 【Method】 Scallops were exposed to cadmium by artificial addition,the cadmium contents in different tissues were determined by atomic absorption spectrophotometer, the expressions of CAT, SOD, GPx and HSP70 genes in the digestive gland of scallop were detected by quantitative real-time PCR. 【Result】Comparing to other tissues, higher concentration of cadmium was accumulated in the digestive gland of scallop(P = 0.004). After exposure to seawater containing 400μg/L of cadmium for 7 days and 10 days, the concentration of Cd in the digestive gland of scallop increased from 62 μg/g(dry weight) to 180 and 217 μg/g(dry weight), respectively. Gene expression of antioxidant enzymes CAT, SOD, GPx and heat shock protein HSP70 in the digestive gland were also increased significantly after the scallop was exposed to 200 μg/L of cadmium for 7 days(P < 0.05).【Conclusion】The digestive gland is an important organ for cadmium accumulation in M. yessoensis.The CAT, SOD, GPx and HSP70 genes play important roles in the defense cadmium stress of scallop.