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Susceptibility to synthetic pyrethroids (SP´s) and the role of two major resistance mechanisms were evaluated in Mexican Rhipicephalus microplus tick populations. Larval packet test (LPT), knock-down (kdr) PCR allele-specific assay (PASA) and esterase activity assays were conducted in tick populations for cypermethrin, flumethrin and deltamethrin. Esterase(More)
Acaricidal activity of organophosphate (OP) and carbamate acaricides is believed to result from inhibition of acetyl-cholinesterase (AChE). Previous studies in Rhipicephalus (Boophilus) microplus demonstrated the presence of three presumptive AChE genes (BmAChEs). Biochemical characterization of recombinant BmAChE proteins expressed in the baculovirus(More)
Boophilus microplus, collected from Nuevo Leon, Mexico, were found to be highly resistant to diazinon but not highly resistant to coumaphos, suggesting that different mechanisms of resistance were present in these ticks than other Mexican organophosphate (OP)-resistant ticks reported previously. When exposed to coumaphos and piperonyl butoxide or(More)
Fresh calf lesnses incubated in nutritive media containing dexamethasone phosphate or ouabain in concentrations ranging from 1 X 10(-4) M to 1 X 10(-8) M developed cortical opacification and showed significant inhibition of Na(+)-K(+) ATP'ase activity. Over a 3-day incubation period the decrease in Na+-K+ ATP'ase activity correlated well with the observed(More)
Fresh calf lenses were incubated in nutritive media, to which was added ouabain and dexamethasone phosphate at concentrations of 1 X 10(-4) M. At the end of a three day incubation period, cortical opacification developed in the control series of lenses as well as those lenses incubated in both ouabain and dexamethasone phosphate. Using a light transmission(More)
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