A novel assay reveals the blockade of esterases by piperonyl butoxide

BACKGROUND: Conventional in vitro assays sometimes fail to reveal esterase inhibition by piperonyl butoxide (PBO), although synergism studies suggest loss of esterase-mediated sequestration of insecticide does take place. A new in vitro assay has been devised that routinely reveals binding between PBO and these esterases. RESULTS: The new 'esterase interference' assay detects the blockade of resistance-associated esterases in a species, Myzus persicae Sulzer, where this has not previously been seen. The assay also demonstrates directly the protective effect esterases may confer to target sites of insecticides. CONCLUSION: The new assay reveals esterase blockade by PBO and thus has the potential to be used as a high-throughput screening method for other potential synergists. (c) 2008 Society of Chemical Industry