INSECTICIDE RESISTANCE AND RESISTANCE MANAGEMENT Comparative Inhibition Kinetics for Acetylcholinesterases Extracted from Organophosphate Resistant and Susceptible Strains of Boophilus microplus (Acari: Ixodidae)
نویسنده
چکیده
In this study, acetylcholinesterases (AChEs)were extracted from twoMexicanBoophilusmicroplus strains thatdemonstrated resistance to theorganophosphate(OP)acaricide, coumaphos, in bioassay. The rate of inhibition of the extractedAChEs by the diethyl-OPparaoxonwas determined for two resistant strains and two susceptible strains ofB.microplus. The time to inhibition of 50%AChE activity was approximately two-fold greater for the resistant strains. Kinetic analysis of the interaction of the resistant AChEswith paraoxon revealed reduced bimolecular reaction constants (ki). Apparent conformational changes in the AChE of the resistant strains were reßected in reduced Km and Vmax values. The bimolecular reaction constants (ki) of the resistant strains were most affected by a slower rate of enzyme phosphorylation (k2).
منابع مشابه
Resistance to coumaphos and diazinon in Boophilus microplus (Acari: Ixodidae) and evidence for the involvement of an oxidative detoxification mechanism.
The levels of resistance to two organophosphate acaricides, coumaphos and diazinon, in several Mexican strains of Boophilus microplus (Canestrini) were evaluated using the FAO larval packet test. Regression analysis of LC50 data revealed a significant cross-resistance pattern between those two acaricides. Metabolic mechanisms of resistance were investigated with synergist bioassays. Piperonyl b...
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