Meeting Abstract

P1.95  Jan. 4  Heat Shock Protein 70 Is Induced At Room Temperature in Hawaiian Drosophila PFIFER, BD*; DOHM, MR; Chaminade University; Chaminade University mdohm@chaminade.edu

Hawaii is typically viewed as a subtropical paradise, with temperatures between 25 and 32 &degC. However, at 1500 meters, the elevation at which members of the Hawaiian Drosophila of the picture-wing group are (were) typically found, the temperature is between 12 and 24 &degC. It is recognized by researchers that husbandry of these flies is possible only at 18 &degC. However, no studies have investigated the physiological or molecular basis of thermal limits in these flies. We therefore quantified inducible heat shock protein (Hsp70) for two species of Hawaiian picture wing flies (Drosophila silvestris and D. heteroneura), and two strains of D. heteroneura: one recently derived (4 generations) from the last known wild population and the other derived from a long-term laboratory strain (20+ years). Hsp70, a chaperone protein, is up-regulated in response to potentially damaging environmental conditions, including elevated temperature. To test basal thermal tolerance, adult flies were incubated once at temperatures between 24 and 36 &degC for 1 hour in a water bath, allowed to recover, and then stored at -70 &degC. Protein was extracted from flies (n = 60), samples were adjusted to 20 &microg/ml of total protein, then Hsp70 content was assessed via ELISA (first: anti-Hsp70/Hsc70 monoclonal antibody; second: goat anti-mouse IgG:AP). The anti-hsp70 antibody we used reflects both constitutive and inducible expressed forms, so all values are reported relative to controls (18 &degC). Compared to controls, flies incubated at 24 &degC for one hour had 2.5 times more Hsp70. At higher temperatures, Hsp70 levels were reduced compared to 24 &degC, but still elevated over controls. We found significantly more hsp70 expression in the long-term compared to short-term strain of D. heteroneura which suggests that the long-term strain has undergone laboratory evolution for thermotolerance.