Characterization of a method for quantitating food consumption for mutation assays in Drosophila.
Quantitation of food consumption is necessary when determining mutation responses to multiple chemical exposures in the sex-linked recessive lethal assay in Drosophila. One method proposed for quantitating food consumption by Drosophila is to measure the incorporation of 14C-leucine into the flies during the feeding period (Thompson and Reeder: Environmental Mutagenesis 10:357-365, 1987). Three sources of variation in the technique of Thompson and Reeder have been identified and characterized. First, the amount of food consumed by individual flies differed by almost 30% in a 24 hr feeding period. Second, the variability from vial to vial (each containing multiple flies) was around 15%. Finally, the amount of food consumed in identical feeding experiments performed over the course of 1 year varied nearly 2-fold. The use of chemical consumption values in place of exposure levels provided a better means of expressing the combined mutagenic response. In addition, the kinetics of food consumption over a 3 day feeding period for exposures to cyclophosphamide which produce lethality were compared to non-lethal exposures. Extensive characterization of lethality induced by exposures to cyclophosphamide demonstrate that the lethality is most likely due to starvation, not chemical toxicity.
Thompson
E D
ED
Miami Valley Laboratories, Procter & Gamble Company, Cincinnati, Ohio 45239.
Reeder
B A
BA
Bruce
R D
RD
D000284:Administration, Oral; D000818:Animals; D002250:Carbon Radioisotopes; D003520:Cyclophosphamide / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology; D004330:Drosophila / Q000235:genetics* / Q000502:physiology; D005038:Ethylnitrosourea / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology; D005247:Feeding Behavior; D005260:Female; D005804:Genes, Lethal; D005808:Genes, Recessive; D007930:Leucine / Q000378:metabolism; D009152:Mutagenicity Tests / Q000379:methods*; D009867:Oogonia / Q000187:drug effects*; D011865:Radioisotope Dilution Technique; D013395:Sucrose
D002250:Carbon Radioisotopes; D013395:Sucrose; D003520:Cyclophosphamide; D007930:Leucine; D005038:Ethylnitrosourea