Biochemical characterization of deltamethrin resistance in a laboratory-selected strain of Aedes aegypti.

A resistant strain (DR) of Aedes aegypti, generated by deltamethrin selection for 20 consecutive generations from a laboratory susceptible strain (DS) was studied for the possible resistant mechanisms. The pyrethroid resistance developed was characterized by biochemical assays and native polyacrylamide gel electrophoresis. Significant elevation in the activity of alpha- and beta-esterases, glucose-6-phosphate dehydrogenase (G6PD), CYTP450 (CYTP450), and glutathione-s-transferase (GST) were noticed in DR. The gel profiles for esterases, G6PD, and CYTP450 were different in DR as compared to DS strain. The difference was either in the form of additional bands or increased intensity of the bands or both. Gel profile variations were also evident from densitometry. Our study suggests that these enzymes play an important role in deltamethrin resistance in the DR strain.