Differential sensitivities of neurotoxic and enzymatic responses to Carbaryl and Acetamiprid in Chilina gibbosa

PAINEFILÚ, J. C.; WOLANSKY, M.J.; HERBERT, L. T.; MENGONI C.; KRISTOFF, G.; COSSI, P. F.; LUQUET CARLOS M.

Buenos Aires

Jornada; Jornadas Interdisciplinarias de Química Biológica; 2017

Departamento de Química Biológica FCEN-UBA

Chilina gibbosa is a freshwater snail endemic to southern Argentina and Chile, commonly found in rivers, lakes and reservoirs of the Río Negro and Neuquén provinces, where fruit production is one of the main economic activities and large amounts of pesticides of different chemical nature have been found in the surrounding water. Our aim was to characterize the acute effect of carbaryl (CAR, carbamate) and acetamiprid (ACP, neonicotinoid) on C. gibbosa neurotoxic response and enzymatic activities. We define neurotoxic response as the protrusion of the entire head-foot. Measured enzymes were cholinesterases (ChE), carboxylesterases (CE) using p-nitrophenyl acetate (p-NPA) and p-nitrophenyl butyrate (p-NPB) as substrates, and glutathione S-transferase (GST). We exposed snails for 48 h to a range of 0.05 to 500 µg L-1 CAR or 10 to 1000 µg L-1 ACP. In the case of CAR, we obtained similar sensitivities between the activities of ChE (NOEC 5 µg L-1; LOEC 13 µg L-1; IC50 37 µg L-1; 75% inhibition at 500 µg L-1) and CE measured using p-NPB (IC50 11 µg L-1; 88% inhibition at 500 µg L-1; no dose response relationship found ≤ 5 µg L-1). There were no effects on the activities of CE using p-NPA and GST. For ACP, we found an increase in CE activity using p-NPA and no effect on ChE, CE using p-NFB and GST. Neurotoxic response was not observed for either pesticide. Our laboratory has previously reported C. gibbosa neurotoxic response and ChE activity as very sensitive biomarkers for acute toxicity of azinphos-methyl (AZM, organophosphate). Contrastingly, ChE activity is less sensitive for CAR and is not altered by ACP. We provide further information on the adverse effects of two different pesticides on an endemic species of South America and aid towards a better ecological risk assessment of pesticides on non-standard organisms.