Affiner votre recherche
Résultats 1-2 de 2
B-type esterases in the snail <em>Xeropicta derbentina</em>: an enzymological analysis to evaluate their use as biomarkers of pesticide exposure
2009
Laguerre, Christel | Sanchez-Hernandez, Juan C. | Köhler, Heinz-R. | Triebskorn, Rita | Capowiez, Yvan | Rault, Magali | Mazzia, Christophe | Abeilles et Environnement (AE) ; Institut National de la Recherche Agronomique (INRA)-Avignon Université (AU) | Santé Végétale (SV) ; Institut National de la Recherche Agronomique (INRA)-École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB) | Universidad de Castilla-La Mancha = University of Castilla-La Mancha (UCLM) | Eberhard Karls Universität Tübingen = Eberhard Karls University of Tuebingen | Steinbeis Transfer-Center for Ecotoxicology and Ecophysiology | Unité de recherche Plantes et Systèmes de Culture Horticoles (PSH) ; Institut National de la Recherche Agronomique (INRA)
International audience | The study was prompted to characterize the B-type esterase activities in the terrestrial snail <em>Xeropicta derbentina</em> 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 x 105–3.80 x 108 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 x 105–2.98 x 108 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<em> X. derbentina</em> are suitable biomarkers of pesticide exposure and that this snail could be used as sentinel species in field monitoring of Mediterranean climate regions
Afficher plus [+] Moins [-]Ageing processes and soil microbial community effects on the biodegradation of soil 13C-2,4-D nonextractable residues
2009
Lerch, Thomas | Dignac, Marie-France | Nunan, Naoise | Barriuso, Enrique | Mariotti, André, A. | Environnement et Grandes Cultures (EGC) ; Institut National de la Recherche Agronomique (INRA)-AgroParisTech | Biogéochimie et écologie des milieux continentaux (Bioemco) ; École normale supérieure - Paris (ENS-PSL) ; Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS)
The biodegradation of nonextractable residues (NER) of pesticides in soil is still poorly understood. The aim of this study was to evaluate the influence of NER ageing and fresh soil addition on the microbial communities responsible for their mineralisation. Soil containing either 15 or 90-day-old NER of C-13-2,4-D (NER15 and NER90, respectively) was incubated for 90 days with or without fresh soil. The addition of fresh soil had no effect on the mineralisation of NER90 or of SOM, but increased the extent and rate of NER15 mineralisation. The analyses of C-13-enriched FAME (fatty acids methyl esters) profiles showed that the fresh soil amendment only influenced the amount and structure of microbial populations responsible for the biodegradation of NER15. By coupling biological and chemical analyses, we gained some insight into the nature and the biodegradability of pesticide NER.
Afficher plus [+] Moins [-]