title: Response of phase II detoxification enzymes in Phragmites australis plants exposed to organochlorines.
abstract: Mixed pollution is a characteristic of many industrial sites and constructed wetlands. Plants possessing an enzymatic detoxifying system that is able to handle xenobiotics seems to be a viable option for the removal of mixed persistent contaminants such organochlorines (OCs: monochlorobenzene (MCB), 1,4-dichlorobenzene (DCB), 1,2,4-trichlorobenzene (TCB), γ-hexachlorocyclohexane (HCH)). In this study, Phragmites australis plants were exposed to sub-lethal concentrations of OCs (7 days), in single-exposure (0.8 to 10 mg l(-1)) and in mixture of OCs (0.2 mg l(-1) MCB + 0.2 mg l(-1) DCB + 2.5 mg l(-1) TCB + 0.175 mg l(-1) HCH). Studies were conducted on the detoxification phase II enzymes; glutathione S-transferases (GST), and glucosyltransferases (UGT). Measurements of GST and UGT activities revealed that OCs may be buffered by glutathione and glucose conjugation. There appeared to be a correlation between the effects on phase II enzymes and the degree of chlorination of the benzene ring with, for example, the greatest effects being obtained for HCH exposure. In the case of mixed pollution, the induction of some GST isoenzymes (CDNB, 35 % non-significant) and UGT (118 %) in leaves and the inhibition of phase II enzymes in the other organs were measured. UGTs appear to be key enzymes in the detoxification of OCs.
authors.affiliation: Laboratoire d'Ecologie Alpine, Research Unit Pollution-Environment-Ecotoxicology-Ecoremediation, UMR CNRS no. 5553, Université Joseph Fourier, BP 53, 38041 Grenoble Cedex 09, France.
authors.forename: Angélique
authors.initials: A
authors.lastname: San Miguel
authors.forename: Peter
authors.initials: P
authors.lastname: Schröder
authors.forename: Rudolf
authors.initials: R
authors.lastname: Harpaintner
authors.forename: Thierry
authors.initials: T
authors.lastname: Gaude
authors.forename: Patrick
authors.initials: P
authors.lastname: Ravanel
authors.forename: Muriel
authors.initials: M
authors.lastname: Raveton
mesh_terms: D001673:Biodegradation, Environmental; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D005964:Glucosyltransferases / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism*; D006843:Hydrocarbons, Chlorinated / Q000378:metabolism* / Q000633:toxicity; D006109:Poaceae / Q000187:drug effects / Q000201:enzymology*; D012989:Soil Pollutants / Q000378:metabolism* / Q000633:toxicity; D013053:Spectrophotometry
chemical_list: D006843:Hydrocarbons, Chlorinated; D012989:Soil Pollutants; D005964:Glucosyltransferases; D005982:Glutathione Transferase