B-type esterases in the snail Xeropicta derbentina: an enzymological analysis to evaluate their use as biomarkers of pesticide exposure |
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Authors: | Laguerre Christel Sanchez-Hernandez Juan C Köhler Heinz R Triebskorn Rita Capowiez Yvan Rault Magali Mazzia Christophe |
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Institution: | a Université d'Avignon et des Pays de Vaucluse, UMR 406 UAPV/INRA, F-84914 Avignon, France b INRA, Laboratoire de Toxicologie Environnementale, UMR 406 UAPV/INRA, F-84914 Avignon, France c Laboratory of Ecotoxicology, Faculty of Environmental Science, University of Castilla-La Mancha, Avda. Carlos III s/n, 45071 Toledo, Spain d Animal Physiological Ecology, University of Tübingen, Konrad-Adenauer-Strasse 20, D-72072 Tübingen, Germany e Steinbeis-Transfer Center for Ecotoxicology and Ecophysiology, Blumenstrasse 13, D-72108 Rottenburg, Germany f INRA, Unité PSH, F- 84914 Avignon, France |
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Abstract: | The study was prompted to characterize the B-type esterase activities in the terrestrial snail Xeropicta derbentina and to evaluate its sensitivity to organophosphorus and carbamate pesticides. Specific cholinesterase and carboxylesterase activities were mainly obtained with acetylthiocholine (Km = 77.2 mM; Vmax = 38.2 mU/mg protein) and 1-naphthyl acetate (Km = 222 mM, Vmax = 1095 mU/mg protein) substrates, respectively. Acetylcholinesterase activity was concentration-dependently inhibited by chlorpyrifos-oxon, dichlorvos, carbaryl and carbofuran (IC50 = 1.35 × 10−5-3.80 × 10−8 M). The organophosphate-inhibited acetylcholinesterase activity was reactivated in the presence of pyridine-2-aldoxime methochloride. Carboxylesterase activity was inhibited by organophosphorus insecticides (IC50 = 1.20 × 10−5-2.98 × 10−8 M) but not by carbamates. B-esterase-specific differences in the inhibition by organophosphates and carbamates are discussed with respect to the buffering capacity of the carboxylesterase to reduce pesticide toxicity. These results suggest that B-type esterases in X. derbentina are suitable biomarkers of pesticide exposure and that this snail could be used as sentinel species in field monitoring of Mediterranean climate regions. |
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Keywords: | Terrestrial snail Cholinesterase Carboxylesterase Pesticides Pralidoxime |
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