Subcellular Distribution and Characterization of Esterase Isozymes from Insecticide-Resistant and -Susceptible Strains of German Cockroach (Dictyoptera: Blatlellidae)

Authors

Suresh K. Prabhakaran, University of Nebraska-Lincoln
Shripat T. Kamble, Universitiy of Nebraska--LincolnFollow

Date of this Version

1994

Comments

Published in J. Econ. Entomol. 87(3): 541-545 (1994) Copyright 1994 Entomological Society of America Used by permission

Abstract

Esterases from insecticide-resistant and -susceptible strains of German cockroach, Blattella germanica (L.), were isolated and analyzed for differences in activity. The isozymes E5, E6, E7, and E8 of resistant strains indicated about two- to fivefold increases in activity compared with those of the susceptible strain. These isozymes constituted ≈60% of the total activity in the resistant strains, whereas they contributed only about 40% activity in the susceptible strain. Subcellular distribution studies showed that most esterase activity is present in the 100,000 x g fraction of the homogenate (cytosolic). Only a small portion of activity was membrane bound. Molecular weights of the esterase isozymes calculated based on their retardation coefficients ranged between 48 and 81 kd.