B-type esterases in the snail Xeropicta derbentina: an enzymological analysis to evaluate their use as biomarkers of pesticide exposure.
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 (K(m)=77.2 mM; V(max)=38.2 mU/mg protein) and 1-naphthyl acetate (K(m)=222 mM, V(max)=1095 mU/mg protein) substrates, respectively. Acetylcholinesterase activity was concentration-dependently inhibited by chlorpyrifos-oxon, dichlorvos, carbaryl and carbofuran (IC50=1.35x10(-5)-3.80x10(-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=1.20x10(-5)-2.98x10(-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.
Laguerre
Christel
C
Université d'Avignon et des Pays de Vaucluse, UMR 406 UAPV/INRA, F-84914 Avignon, France.
Sanchez-Hernandez
Juan C
JC
Köhler
Heinz R
HR
Triebskorn
Rita
R
Capowiez
Yvan
Y
Rault
Magali
M
Mazzia
Christophe
C
D000110:Acetylcholinesterase / Q000032:analysis*; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D043182:Carboxylesterase / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D004781:Environmental Exposure; D004784:Environmental Monitoring / Q000379:methods; D007306:Insecticides / Q000032:analysis / Q000633:toxicity*; D009943:Organophosphorus Compounds / Q000032:analysis / Q000633:toxicity*; D012908:Snails / Q000201:enzymology*
D015415:Biomarkers; D007306:Insecticides; D009943:Organophosphorus Compounds; D043182:Carboxylesterase; D000110:Acetylcholinesterase