A non-genetic esterase in drosophila

A non-genetic esterase allozyme found in polyacrylamide gel electrophoresis of laboratory stocks of Drosophila was studied. Staphylococcus epidermidis was isolated from allozyme-positive flies and was found to produce a co-migrating esterase when grown on nutrient agar. Electrophoretic comparison of flies grown on food inoculated with. epidermidis and flies grown on food containing tetracycline HCI supported the hypothesis that the allozyme is of bacterial origin. Supporting evidence in the literature was reviewed. The mode of Drosophila stock contamination with the bacterium was postulated, and the advantages of short-term incorporation of antibiotics into Drosophila medium were discussed.