EVALUATION OF OXIDATIVE STRESS BIOMARKERS IN Cydia pomonella ADULT FROM DIFFERENT FIELD POPULATIONS OF ARGENTINEAN PATAGONIA

ELIZABETH MAERO; CRISTINA M MONTAGNA; LILIANA CICHÓN; SILVINA GARRIDO; OLGA L ANGUIANO

Guarapari

Congreso; XIII Congresso Brasileiro de Ecotoxicologia; 2014

Sociedad Brasilera de Ecotoxicología

Abstract The codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is one of the main worldwide pest of apples, pears and walnuts. For many years, pesticide applications have been the dominant tools used for its control. Many pesticides are known to induce oxidative stress due to generation of free radicals and alteration of antioxidant defense mechanisms in both vertebrate and invertebrate organisms. Oxidative stress can be defined as an imbalance between the production of free radicals and the body antioxidant defense system -enzymatic and non-enzymatic. Some oxidative stress biomarkers in Cydia pomonella adults from field populations of different orchards in Argentinean Patagonia and a laboratory reference one were investigated. Diapausing larvae of C. pomonella from Centenario (Neuquén province), Guerrico and Godoy (Río Negro province), and Sarmiento1 and Sarmiento2 (Chubut province) were collected using corrugated cardboard traps in fall 2013, and used for assays after emergency. Two antioxidant enzymes including catalase (CAT) and glutathione S-transferase (GST) were analyzed. Levels of reduced glutathione (GSH) and lipid peroxidation were also evaluated. GST was determined using 1-chloro-2,4-dinitrobenzene (CDNB) as substrate according to Habig et al (1974). CAT activity was determined (Beers and Sizer, 1952) by following the rate of disappearance of H2O2 at 240 nm. GSH content was quantified by method of Ellman (1959) and the lipid peroxidation was estimated by the formation of malondialdehyde (MDA) according to Ortega-Villasante et al (2005). Codling moth from Sarmiento2 showed significantly higher levels of GSH (34.896  3.635 nmoles GSH/mg protein) than organisms from the other sites. The lowest GSH contents were observed in Centenario and Guerrico populations (10.614  1.953 and 14.240  1.478 nmoles GSH/mg protein). The organisms from all field populations showed GST activities significantly lower than the reference population (p < 0.001). The minimum level of GST activity (0.054  0.016 mol CDNB/min mg protein) was measured at Sarmiento1 population. CAT activity did not exhibit significant differences between field populations and the laboratory reference one. MDA contents varied from 0.023 to 0.524 pmoles MDA/mg protein. The highest level of MDA (0.524  0.133 pmoles MDA/mg protein) was found in Centenario population, and was statistically different (p < 0.01) from each others. Sarmiento1, Godoy and Guerrico organisms showed significantly lower MDA levels than the levels found at the reference population. The low GSH content observed in adult from Centenario could explain the enhancement of lipid peroxidation in organisms from this site. On the other hand, we observed an adaptive response to oxidative stress of Sarmiento2 organisms characterized by a significant increase in GSH content. Moreover, high levels of this tripeptide have been associated with an increase in pesticide tolerance in two species marine bivalves (Peña-Lopis at al, 2002). Reduced GST activities measured in all field populations would indicate its poor protective role against antioxidant pollutants. In conclusion, our results suggest that defense antioxidant mechanisms are activated in adult field populations of C. pomonella. Finally, the parameters GST, GSH and MDA may be used as biomarkers of exposure to oxidant pollutants. Beers RF, Sizer JW. A spectrophotometric method for measuring the breakdown of hydrogen peroxide by catalase. Journal of Biological Chemistry 1952; 195(1): 133-140. Ellman GL. Tissue sulfhydryl groups. Archives of Biochemistry and Biophysics 1959; 82(1): 70-77. Habig WH, Pabst MJ, Jacoby WB. Glutathione S-transferases: The first enzymatic step in mercapturic acid formation. Journal of Biological Chemistry 1974; 249: 7130-7139. Ortega-Villasante C, Rellan-Alvarez R, Del Campo, FF, Carpena-Ruiz RO, Hernandez LE. Cellular damage induced by cadmium and mercury in Medicago sativa. Journal of Experimental Botany 2005; 418: 2239-2251. Peña-Llopis S, Ferrando MD, Peña JB. Impaired glutathione redox status is associated with decreased survival in two organophosphate-poisoned marine bivalves. Chemosphere 2002; 47: 485-497.