Partial purification and characterization of a methyl-parathion resistance-associated general esterase in Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae)

Authors

Xuguo Zhou, University of Nebraska-Lincoln
Michael E. Scharf, Purdue University-West Lafayette, IN
Gautam Sarath, University of Nebraska-LincolnFollow
Lance J. Meinke, University of Nebraska-LincolnFollow
Laurence D. Chandler, USDA-ARSFollow
Blair Siegfried, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

1-16-2004

Comments

Published in Pesticide Biochemistry and Physiology 78 (2004) 114–125.

Abstract

Increased hydrolytic metabolism of organophosphate insecticides has been associated with resistance among Nebraska western corn rootworm populations. In this study, resistance-associated esterases were partially purified by differential centrifugation, ion exchange, and hydroxyapatite column chromatography, with a final purification factor of 100-fold and recovery of approximately 10%. Kinetic analysis of the partially purified enzyme indicated that the K_m of the group II esterases was identical for the two populations, although V_max was consistently threefold higher in the resistant population. A putative esterase, DvvII, was further purified to homogeneity by preparative polyacrylamide gel electrophoresis. DvvII is a monomer with a molecular weight of approximately 66 kDa, although three distinct isoforms with similar pIs were evident based on isoelectric focusing gel electrophoresis. Immunoassays with the Myzus persicae E4 antiserum indicated that group II esterases from D. v. virgifera were cross-reactive and expressed at much higher titers in the resistant population relative to the susceptible counterpart. These results suggest that the resistance is likely associated with overproduction of an esterase isozyme in resistant D. v. virgifera populations.