重金属Cd^(2+)胁迫对近江牡蛎超氧化物歧化酶活性的影响

Effects of heavy metal Cd^(2+) on superoxide dismutase (SOD) activity of Crassostrea rivularis

探讨了将近江牡蛎抗氧化酶防御体系参数作为海洋重金属污染生物监测指标的可行性。在实验室条件下,研究重金属Cd2+胁迫对近江牡蛎Crassostrea rivularis鳃和消化腺组织超氧化物歧化酶(SOD)活性的诱导作用。结果表明,Cd2+对近江牡蛎消化腺组织SOD活性诱导的剂量效应呈抛物线型,而对鳃组织SOD活性诱导曲线呈非抛物线型,由于二者结构和功能的不同,前者的SOD活性高于后者;低浓度Cd2+(0.1mg.L-1)对近江牡蛎鳃组织SOD活性表现为显著诱导,中(0.5mg.L-1)、高(1.5mg.L-1)浓度Cd2+对近江牡蛎鳃组织SOD活性诱导呈先升后降的变化趋势;低、中浓度Cd2+对近江牡蛎消化腺组织SOD活性均表现为显著诱导,高浓度Cd2+对近江牡蛎消化腺组织SOD活性诱导呈先升后降的变化趋势。研究表明,对于水体中单一因子的Cd2+污染物而言,近江牡蛎消化腺组织中的SOD活性对其有一定的指示意义,但将其作为指标应用到实际养殖水体尚须进一步研究。

In order to discuss the feasibility of monitoring heavy metal pollution in breeding water by antioxidant enzyme in Crassostrea rivularis, the activities of SOD in gills and digestive glands of C. rivularis induced by exposure to Cd^2＋ were studied under laboratory conditions. The results showed that the SOD activity in the digestive glands induced by Cd^2＋ was higher than that in the gills due to the differences in structure and function of the two tissues. The variation of the SOD activity induced by different concentrations of Cd^2＋ showed a parabola trend in the digestive glands, but not in the gills. The SOD activity in the gills increased greatly with the exposure time at a low concentration of Cd^2＋ （0.1mg·L^-1 ）, while the activity was induced significantly during the initial period but decreased rapidly later at moderate （0.5mg·L^-1） and high （1.5mg·L^-1） concentrations. In the digestive glands, the SOD activity was induced significantly at low and middle concentrations of Cd^2＋ , and increased greatly in a short time but went down rapidly at a high concentration of Cd^2＋. The present studies showed that the activity of SOD in the digestive glands of C. rivularis could be used as a monitoring index of heavy metal Cd^2＋ pollution for water under experimental conditions, but for actual breeding water, further studies need to be carried out later.