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 Sülzer, where this has not previously been seen. The assay also demonstrates directly the protective effect esterases may confer to target sites of insecticides.


CONCLUSIONS
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.
Khot
Anna C
AC
Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
Bingham
Georgina
G
Field
Linda M
LM
Moores
Graham D
GD
D000818:Animals; D001042:Aphids / Q000201:enzymology*; D001681:Biological Assay; D004950:Esterases / Q000037:antagonists & inhibitors*; D063086:Organothiophosphates / Q000494:pharmacology; D010574:Pesticide Synergists / Q000494:pharmacology*; D010882:Piperonyl Butoxide / Q000494:pharmacology*
D063086:Organothiophosphates; D010574:Pesticide Synergists; C072763:azamethiphos; D004950:Esterases; D010882:Piperonyl Butoxide