镉和锌对中华小长臂虾(Palaemonetes sinensis)金属硫蛋白表达的影响

Influence of Cadmium and Zinc on the Expression of Metallothionein in Chinese Grass Shrimp (Palaemonetes sinensis)

为系统研究重金属离子(镉和锌)诱导的金属硫蛋白在中华小长臂虾(Palaemonetes sinensis)不同组织(肝胰脏、肌肉)中的表达,采用水相暴露法对中华小长臂虾进行镉(0,0.05,0.08,0.10和0.15mg·L^(-1))与锌(0,5,8,15和18mg·L^(-1))的急性染毒试验。通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳(SDS-PAGE)方法分析不同浓度的镉、锌离子在不同染毒时间下(0,24,48和96h),诱导金属硫蛋白(metallothionein,MT)在中华小长臂虾不同组织中的表达差异。结果表明:镉和锌诱导中华小长臂虾MT的表达存在组织差异性和时间效应关系。在肌肉中镉离子和锌离子不能诱导MT的表达。在肝胰脏中,0.05mg·L^(-1)的镉离子可诱导MT的表达,而5mg·L^(-1)的锌离子才能达到相同的效果。两种离子相比较,镉对中华小长臂虾的MT诱导能力更强。时间效应表现为染毒48h肝胰脏中MT表达量最高,诱导表达量随暴露时间的增加而加大,但达到一定程度后即呈下降至稳定趋势。两种重金属对中华小长臂虾肝胰脏MT的诱导能力:Cd^(2+)>Zn^(2+);MT在中华小长臂虾不同组织中的分布顺序为:肝胰脏>肌肉。染毒后中华小长臂虾肝胰脏中MT的表达有一定的时间效应关系,48h的表达量最高。

In order to systematically study the expression of metallothionein induced by heavy metal ions（cadmium, zinc） in different tissues（hepatopancreas, muscles） of Palaemonetes sinensis, the water phase exposure method was used to treat the Chinese grass shrimps. The shrimps were exposed to cadmium（0, 0.05, 0.08, 0.10 and 0.15 mg·L^-1） and zinc（0, 5, 8, 15 and18 mg·L^-1） at different times（0, 24, 48 and 96 h）. By SDS-polyacrylamide gel electrophoresis（SDS-PAGE） method, the expression of metallothionein（MT） in different tissues of Palaemonetes sinensis was investigated under different concentrations of cadmium and zinc. The results showed that there were tissue differencea and time effects on the expression of MT in Palaemonetes sinensis induced by cadmium and zinc. Cadmium and zinc could not induce MT expression in muscle. In the hepatopancreas, 0.05 mg·L^-1 cadmium ion induced MT expression, and 5 mg·L^-1 zinc achieved the same effect. Compared between the two kinds of ions, cadmium had stronger ability of inducing MT on Palaemonetes sinensis. The time effect showed that the expression of MT in hepatopancreas was the highest at 48 h after exposure, the expression level increased with the increase of exposure time, and decreased to a stable trend after reaching a certain level. This study showed that the ability of MT inducing hepatopancreas of Palaemonetes sinensis was determined by two heavy metals： Cd^2＋〉Zn^2＋; the distribution of MT in Palaemonetes sinensis was hepatopancreas〉 muscle. The expression of MT in the hepatopancreas of Palaemonetes sinensis had a certain time-effect relationship after exposure, and the expression was highest at 48 h.