Genetico-Biochemical Analysis of Specific Esterases in Musca Domestica

In order to classify the multiple molecular forms of esterases in house flies which can be revealed by unspecific substrates such as α- or β-naphthylacetate in thin-layer electrophoresis, substrate specificity and susceptibility to selective inhibitors have been studied. Specific esterases were revealed by using a pH-indicator method which can be applied to any substrate. The esterases hydrolysing acetylcholine, methyl-n-butyrate, ethyl-n-butyrate, tributyrin, phenylacetate and phenyl-n-butyrate were compared with esterases splitting β-naphthylacetate, and effects of eserine and TOCP (tri-o-cresyl phosphate) on their zymograms were studied. It is suggested that four types of esterases may be distinguished in house fly homogenates.Genetic analysis on a factor responsible for formation of the butylester-splitting enzyme which has a lower activity in diazinon resistant house flies showed that it is controlled by a recessive gene on the 5th chromosome, on which diazinon-resistance gene and the genes controlling the majority of esterase bands are already known to be located.