Jm. Wierenga et Rm. Hollingworth, THE ROLE OF METABOLIC ENZYMES IN INSECTICIDE-RESISTANT COLORADO POTATO BEETLES, Pesticide science, 40(4), 1994, pp. 259-264
Several metabolic enzymes were assayed in susceptible and insecticide-
resistant (R-mfo and R-AchE) strains of the Colorado potato beetle (Le
ptinotarsa decemlineata Say). We compared the activities of esterases,
glutathione transferases and mixed function oxidases, and measured in
-vivo metabolism of carbofuran to determine the contributions of metab
olic factors to the observed resistance. There were no substantial dif
ferences between strains in alpha- or beta-naphthylacetate hydrolysis,
or in glutathione transferase activity. Compared to the susceptible s
train, the R-mfo strain showed 4-fold higher activity in both ethoxyre
sorufin-O-dealkylase, and pentoxyresorufin-O-dealkylase activity. The
R-AChE strain had a 1-5-fold higher level of ethoxyresorufin-O-activit
y. Correspondingly, the in-vivo metabolism of carbofuran was highest i
n the R-mfo strain, and the R-AChE strain was slightly higher than the
susceptible strain. These results are discussed in relation to other
resistance mechanisms which we have examined in these strains.