Biotransformation of endosulfan by the tiger worm, Eisenia fetida

摘要

This study assesses the role of the earthworm, Eisenia fetida, in the breakdown of endosulfan in a soil environment. Two strains of E. fetida were used in this study to assess the effect of salinity on toxicity and metabolism of endosulfan in these earthworms. One strain of E. fetida (R) was reared in high salinity soil (over 2.0 dS/m of electric conductivity) from Shiwha lake, Korea. A control strain (W) was reared in pig manure compost. Acute toxicity of endosulfan was lower in the R strain when endosulfan was injected. In vitro metabolic studies of endosulfan based on microsomal preparations showed that both strains produced two major metabolites, endosulfan sulfate and endosulfan diol. The production rate of endodulfan sulfate was not significantly different between the strains, while endosulfan diol production was significantly different. In vivo metabolism studies showed only one primary metabolite, endosulfan sulfate, was produced by both strains. HPLC-MS/MS analysis showed annetocin was the indicative protein newly expressed in the R strain in relation to salinity exposure. These findings suggest salinity may induce hydrolyzing enzymes to produce endosulfan diol from endosulfan.