短期暴露于城市污水处理厂尾水的文蛤抗氧化酶响应

为研究城市污水处理厂(STPs)尾水是否会引起海洋生物的氧化逆境,将取自青岛市李村河污水处理厂的尾水用海水稀释到不同浓度(0%、1%、5%、10%、20% V/V), 对文蛤(Meretrix meretrix)暴露培养15d, 分析其内脏中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPx)、谷胱甘肽还原酶(GR)的活性. 结果表明:SOD活性随尾水暴露时间延长基本表现为“抛物线型”的响应特征,体积比10%、20%的尾水暴露6~12d期间,文蛤体内SOD活性均受到诱导,最大增幅为15.88%;CAT和GPx对尾水的主要响应特征是抑制效应,分别在暴露9d、12d时最为明显,最大抑制率分别为64.38%和52.39%;较高浓度(20%)的尾水能够持续抑制GR活性,而其他处理组中,GR对尾水表现为“抛物线型”的响应特征,即:暴露3d或6d时活性增加,而后显著降低.GR活性的最大诱导出现在暴露3d和6d时,分别比对照组上升81.47%和80.91%.研究结果进一步表明STPs不能有效降解有害化学物质以消除尾水的毒性, 文蛤内脏SOD、CAT、GPx和GR活性能够敏感指示尾水诱导的氧化逆境.

Responses of the antioxidant enzymes in Meretrix meretrix exposed to effluent from municipal sewage treatment plants for short-term

In order to investigate if effluent from municipal sewage treatment plants (STPs) cause oxidative stress in marine organisms, Meretrix meretrix were exposed to effluent from the Licunhe STP in Qingdao City at various concentrations (0%, 1%, 5%, 10% and 20% V/V), diluted in seawater, for 15days. Antioxidant enzymes analyzed in the viscera of mussels were superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR). Results showed that the variation trend of SOD activities with exposure time exhibited a parabolic curve shape with a maximal increment of 15.88%, which was induced from day 6 to day 12 in both exposure groups (10% and 20% effluent). Both CAT and GPx were inhibited by the effluent with the highest inhibition 64.38% and 52.39%, at the day 9 and day 12, respectively. At higher effluent concentration (20%), GR activity was inhibited constantly during the exposure period. However, GR activities responded in a parabolic curve shape in other exposure groups where an initial increase was observed at day 3 or day 6 followed by a significant decrease after day 9, and the highest increment were 81.47% and 80.91%, at day 3 and day 6, respectively. Current experimental results suggest that STPs do not have the capacity to biodegrade harmful chemicals sufficiently to prevent toxic action of effluent, and SOD, CAT, GPx and GR activities in viscera of M. meretrix are sensitive indicators of oxidative stress induced by effluent.