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| Effects of Cadmium on Glutathione Contents and Activities of Glutathione Related Enzymes in Gill and Hepatopancreas of Anodonta woodiana woodiana |
| Received:August 01, 2014 |
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| KeyWord:Anodonta woodiana woodiana;gill;hepatopancreas;glutathione;concentration;enzyme activity;cadmium |
| Author Name | Affiliation | E-mail | | YANG Hui-zhen | Shanxi University School of Life Science, Taiyuan 030006, China | | | LIU Na | Shanxi University School of Life Science, Taiyuan 030006, China | | | LI Yong-quan | Shanxi University School of Life Science, Taiyuan 030006, China | | | WEI Xiao-xi | Shanxi University School of Life Science, Taiyuan 030006, China | | | WANG Lan | Shanxi University School of Life Science, Taiyuan 030006, China | lanwang@sxu.edu.cn |
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| Abstract: |
| Glutathione system is an important defense system against oxidative damages. In this study, an experiment was designed to examine the dynamics of glutathione contents and activities of glutathione related enzymes in Anodonta woodiana woodiana under six Cd treatments(0, 4.22, 8.43, 16.86, 33.72 mg·L-1 and 67.45 mg·L-1 of Cd) for 24 h, 48 h, 72 h and 96 h, according to 134.9 mg·L-1 of LC50 for Cd within 96 h. The reduced glutathione(GSH) and oxidized glutathione(GSSG) concentrations as well as glutathione transferase(GST) and glutathione reductase(GR) activities were measured in the gill and hepatopancreas tissues. Compared with the control, Cd treatments significantly decreased both GSH and GSSG concentrations in the gills, with exception of one treatment group(4.22 mg·L-1, 48 h). The ratio of GSH/GSSG was decreased in two treatment groups(4.22 mg·L-1 and 8.43 mg·L-1, 48 h). However, this ratio was increased in some other groups(67.45 mg·L-1 in 24 h, 48 h and 96 h, 4.22 mg·L-1 in 72 h and 8.43 mg·L-1 in 96 h). The GST activity in the gills rose by Cd treatments, except the groups treated for 24 h, in which GST showed a gradient decrease. The GR activity increased in three groups(8.43 mg·L-1 in 48 h, 67.45 mg·L-1 in 72 h and 4.22 mg·L-1 in 96 h) in the gills. In the hepatopancreas, GSH content and GSH/GSSG ratio significantly reduced as the Cd concentration and exposure time increased. The activity of GST in the hepatopancreas was dependent on Cd concentrations and treatment time, with the greatest activity observed in 4.21 mg·L-1 in 24 h. It decreased at higher Cd concentrations and extended time. In the hepatopancreas, the GR activity was increased in the following treatment groups(4.22 and 8.43 mg·L-1 in 24 h, 4.22 mg·L-1, 16.86 mg·L-1 and 67.45 mg·L-1 in 72 h and all concentrations in 96 h except for 67.45 mg·L-1). In conclusion, our results show that Cd exposure can decrease the concentrations of GSH and GSSG but increase the levels of GST and GR in the gill and hepatopancreas, indicating that the antioxidant defense system is activated in response to Cd-induced oxidative damages in Anodonta woodiana woodiana. The GSH in hepatopancreas showed a consistent decrease in response to Cd toxicity regardless of concentrations and time of Cd exposure, and GST activity was also sensitive to Cd toxicity. Hepatopancreas had a faster response than gills did. Therefore, the GSH level and GST activity in hepatopancreas can be used as biological indicators for monitoring contamination by metals such as Cd. |
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