World Congress of Malacology Antwerp ... - Unitas Malacologica

B-type esterases in the snail Xeropicta derbentina as potential biomarkers of pesticide exposure:
in vitro inhibition and reactivation
Laguerre, Christel 1 ; Sanchez-Hernandez, Juan C. 2 ; Köhler, Heinz-R. 3 ; Capowiez, Yvan 1 ;
Rault, Magali 1 ; Mazzia, Christophe 1
1. Laboratoire de Toxicologie Environnementale, UMR 406 INRA/UAPV, Ecologie
des Invertébrés, Site Agroparc, 84914 Avignon Cedex 9 France,
Email: mazzia@avignon.inra.fr
2. Laboratory of Ecotoxicology, Faculty of Environmental Science, University of
Castilla-La Mancha, Avda. Carlos III s/n, 45071, Toledo, Spain,
3. Animal Physiological Ecology, University of Tübingen, Konrad-Adenauer-Str. 20,
D-72072 Tübingen, Germany
Inhibition of the B-type esterase (cholinesterase [ChE] and carboxylesterase [CbE]) activities is one
of the most used biomarker for assessing exposure to organophosphorus (OP) and carbamate (CB)
pesticides. The aims of this work are 1) to characterize ChE and CbE activities in the snail Xeropicta
derbentina, 2) to evaluate the effects of the OPs chlorpyrifos-oxon and dichlorvos and the CB
carbofuran on the B-type esterase responses and 3) to test whether chemical reactivation of inhibited
ChE with pyridine-2-aldoxime-methochloride (2-PAM) can be a complementary methodology of
pesticide exposure for field monitoring purposes.
In vitro experiments were performed on postmitochondrial supernatants. CbE basal specific activities
were 32.88, 229.71 and 221.28 mU/mg of protein for α-napththyl acetate, p-nitrophenyl valerate and
p-nitrophenyl acetate, respectively. The mean ChE activity was 25 mU/mg of protein.
Acetylcholinesterase activity is the major type of soluble ChE form (80 % of total ChE activity) in X.
derbentina.
CbE activity was dose-dependently inhibited by the OPs but not by carbofuran. ChE activity was
dose-dependently inhibited by the three pesticides but it was more sensible to carbofuran (IC50 = 9.7
10 -8 M) than dichlorvos (IC50 = 2.98 10 -7 M) or chlorpyrifos-oxon (IC50 = 2.27 10 -7 M). The OPinhibited
ChE activity was reactivated in the presence of 5 x 10 -4 M 2-PAM after 30-min incubation.
The reactivation kinetics for chlorpyrifos- and dichlorvos-inhibited ChE followed an exponential rise
to recover a maximum of 75% and 65%, respectively.
These preliminary results pointed out three important features: (i) the different CbE sensibility of X.
derbentina to OPs and CB compounds could explain the different ChE sensibility to these chemicals,
(ii) CbE activity was resistant to inhibition by carbofuran and (iii) the chemical reactivation of
phosphorylated ChE activity of X. derbentina enormously extends the practical possibilities of this
organism as bioindicator of pesticide contamination.
Xeropicta derbentina as a sentinel species for evaluating ecotoxicological effects of pesticide
treatments?
Laguerre, Christel 1 ; Lazzara, Raimondo 2 ; Köhler, Heinz-R. 2 ; Triebskorn, Rita 2,3 ; Sanchez-
Hernandez, Juan C. 4 ; Capowiez, Yvan 1 ; Rault, Magali 1 ; Mazzia, Christophe 1
Laboratoire de Toxicologie Environnementale, UMR 406 INRA/UAPV, Ecologie
des Invertébrés, Site Agroparc, 84914 Avignon Cedex 9 France,
Email: mazzia@avignon.inra.fr
Animal Physiological Ecology, University of Tübingen, Konrad-Adenauer-Str. 20,
D-72072 Tübingen, Germany,
Steinbeis-Transfer Center for Ecotoxicology and Ecophysiology, Blumenstr. 13, D-
72108 Rottenburg, Germany,
Laboratory of Ecotoxicology, Faculty of Environmental Science, University of
Castilla-La Mancha, Avda. Carlos III s/n, 45071, Toledo, Spain
Xeropicta derbentina is among the most frequently encountered land snails in Mediterranean
countries. Due to their good adaptation to warm countries and their summer activity, these snails
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