Adaptation of Drosophila to temperature: Heat‐shock proteins and survival in Drosophila melanogaster

Abstract

Abstract Two stocks of Drosophila melanogaster, one sensitive (6.5% survival) and one resistant (76.24%) to heat shock (40°C/25 min) were derived through indirect selection [1]. Genetic analysis of heat‐sensitive and heat‐resistant lines we had selected revealed that the survival rate is chiefly determined by cytoplasmic inheritance but also depends to some extent on the nucleus [1]. The ability of the fly to survive thermal stress was found to have an excellent correlation with the kinetics of protein synthesis in ovaries or glands subjected to heat treatment. The incorporation rate of 35 S‐methionine into proteins was found to be higher for strains exhibiting higher survival (R 1 , R 1 S 1 ) than for strains with a lesser ability (S 1 , S 1 R 1 ) to survive heat shock. Moreover, the intensity of labeling of the proteins synthesized and especially of the hsps (heat‐shock proteins) after the heat shock is higher in the R 1 and R 1 S 1 stocks than in the S 1 and S 1 R 1 stocks. This convergence between survival and the cellular level of hsps (both manipulated by selection) bears on the physiological significance of these proteins which seems to participate in the control of the survival as an additive component.