Genotypical peculiarities of the β-specific hydrolase allozymeS expression of the carboxylic ethers in Drosophila melanogaster of the wild type

Using the method of computer densitometry we have determined the expression level of the electrophoretically separated S- and F-allozymes of β-specific esterase (E.C. 3.1.1.2) in Drosophila melanogaster homozygotes and heterozygotes for β-Est locus. α-naphtylacetate, β-naphtylacetate and α-naphtylpropionate were used as substrates. Expression intensity of the esterases was estimated using the quantity of the reaction product which is created as a result of simultaneous azocoupling between naphtol and diazonium during 4, 24, 44 and 64 min of incubation time. We have established the reliable differences between the S- and F-allozyme expression depending on the β-Est locus structure. In all the variants the higher level of summary activity S- and F-allozymes of β-esterase of the heterozygotes comparing to those of two types of homozygotes was demonstrated independently of the Drosophila sex. We compared the characteristics of the expression dynamics of the allozymes of dominant homozygotes (β-Est^S/β-Est^S), heterozygotes (β-Est^S/β-Est^F) and recessive homozygotes (β-Est^F/β-Est^F). We also consider some possible mechanisms of heterosis of S- and F-allozyme expression according to the theory of biochemical enrichment of heterozygote genotypes.

Keywords: expressivity of the β-esterase allosimes, heterosis, drosophila melanogaster