Levels of total acetylcholinesterase in Drosophila melanogaster in relation to insecticide resistance

Titration of acetylcholinesterase active sites was used to estimate the lev el of acetylcholinesterase in 82 Drosophila melanogaster strains originatin g from several countries. The amount of enzyme varied by up to a factor of twofold and was directly correlated with insecticide resistance. This sugge sts that increased acetyleholinesterase production contributes to resistanc e. This mechanism adds to the qualitative modifications of aceLylcholineste rase, which render me enzyme less sensitive to inhibition by insecticides. As these qualitative modifications of the active site of the enzyme usually result in a decrease in the rate of neurotransmitter hydrolysis, they may affect the fitness of the flies. Overproduction of a modified acetylcholine sterase appears to be a potential modifier since it compensates for the dec rease in neurotransmitter hydrolysis. (C) 2001 Academic Press.