Papers by Author: Chang Hai Wang

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Authors: Ai Li Jiang, Zhen Yu, Chang Hai Wang
Abstract: Based on the semi-static two compartment model, the bioconcentration and elimination of copper with tissues of Styela clava were investigated. The kinetic parameters (accumulation rate constant k1, elimination rate constant k2, bioconcentration factor BCF, biological half life t1/2 and maximum equilibrium concentration CAmax) were obtained by non-linear regression. The results showed S. clava could accumulate copper from the aquatic environment and that BCF decreased with increasing metal concentration in water. When the accumulation achieved balance, CAmax showed positive correlation to metal concentrations in water. Concentrations of copper in different tissues of S. clava were in the order of gonad > digestive gland ≈ other part >tunic, and t1/2 of copper was 12.57 to 38.18 days in elimination phase. The high rate to accumulate and eliminate copper from its body exhibited a useful potential biomonitor of short-term copper fluctuations status in marine system.
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Authors: Ai Li Jiang, Zhen Yu, Chang Hai Wang
Abstract: Styela clava were exposed to sublethal concentrations of methamidophos (5.0, 10.0 and 15.0 μg/L) for 96 h, its biochemical stress response was studied taking into account carboxylesterase (CbE), catalase (CAT), SOD and glutathione S-transferase (GST) activities, as well as reduced glutathione (GSH) levels in tissues. In all exposed groups CbE was significantly inhibited. GSH level was reduced after exposure, and CAT activity decreased continuously. 24 h exposure to methamidophos did not affect GST activity. The results show that the early inhibitory effect in CAT activity and GSH content produced by methamidophos may be associated with a high degree of oxidative stress. CbE inhibition is a good biomaker for methamidophos exposure. This study revealed that S. clava developed adaptive response to neutralize the oxidative stress following pesticide exposure and that SOD and GPx can be used as biomarker in determining methamidophos toxicity due to its early response at even low concentration levels.
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