ARS | Publication request: Effects of esculetin on activities of some antioxidant enzymes of Galleria mellonella and its parasitoid Bracon hebetor

Submitted to: European Congress of Entomology
Publication Type: Abstract Only
Publication Acceptance Date: October 30, 2006
Publication Date: November 6, 2006
Citation: Buyukguzel, E., Teerzi, B., Durmus, Y., Buyukguzel, K., Stanley, D.W. 2006. Effects of esculetin on activities of some antioxidant enzymes of Galleria mellonella and its parasitoid Bracon hebetor [abstract]. European Congress of Entomology. p. 52.

Technical Abstract: Eicosanoids mediate several physiological responses, including immune defense reactions. Two major groups of eicosanoids are prostaglandins (products of cyclooxygenase pathways) and various products of lipoxygenase pathways. Antioxidant response is one of the defense mechanisms to oxidative damage of endogenous and exogenous free radicals in insects. The goal of this study was to test the hypothesis that lipoxygenase products mediate antioxidative response of insects. We investigated the effects of a lipoxygenase inhibitor, esculetin, on activities of some antioxidant enzymes in each developmental stage of greater was moth, Galleria mellonella (L.) and its ectoparasitoid Bracon hebetor (Say). Newly hatched larvae of G. mellonella were reared on an artificial diet containing different concentrations of the inhibitor. The late last instars reared from these diets with given concentrations were used as esculetin-contaminated hosts for rearing of B. hebetor larvae. As bioindicators of physiological stress responses of the host and parasitoid, alterations in activities of antioxidant enzymes, glutathione-S-transferst (GST) and catalase (CAT) were assessed. The results indicate that esculetin impaired activities of antioxidant enzymes in comparison to untreated control groups and it disables enzymatic antioxidant capacity of insects by inhibiting biosynthesis of lipoxygenase products. Moreover, this inhibitor influenced the activities of the enzymes in a dose-dependent manner. We interpret these findings and their significance with respect to integration of the biological control with chemical control of insects. The study supports the hypothesis that lipoxygenase products are the mediators of antioxidative enzymatic reactions in insects.