论文部分内容阅读
Laboratory experiments were carried out to determine zinc accumulation and glutathione defense system in freshwater fish Carassius auratus.Fish were subjected to different concentrations of Zn2+ and its EDTA complex (0.05, 0.1, 0.5, 1 and 2 mg/L) after 40 days of exposure.The chemical analyses showed higher zinc concentrations for Zn2+ treatments followed by Zn-EDTA.At the lowest Zn2+ or Zn-EDTA level, decreases of glutathione reductase (GR), oxidized glutathione (GSSG) content and reduced glutathione (GSH) content were observed.GSSG, GSH and tGSH (total glutathione) content were almost suppressed with Zn2+ treatments.GSH/GSSG ratio increased at the lowest Zn2+ level but decreased with higher exposure, but the ratio almost increased markedly with Zn-EDTA exposure.Glutathione antioxidant systems are sensitive to lower Zn-EDTA levels (< 0.5 mg/L).These parameters of glutathione system are valuable tools in the study of oxidative stress in aquatic ecosystems.