Stress Proteins Elicited by Cold Shock in the Biting Midge, Culicoides variipennis sonorensis Wirth and Jones

In vivo protein expression in the abdominal viscera of C. v. slmorensis was examined from aduh flies that were cold shocked for various lengths of time at O, 10, or 15°C and labelled at 25°C with 35S-methionine at 0, 2, 4 and 6 hr during the recovery period. In vitro labelling showed that seven unique proteins (23, 40, 43, 48, 60, 70 and 92 kDa) were produced in C. v. sonorensis exposed to low temperatures in vivo. In general, the rate of expression and quality of stress proteins were directly proportional to both the severity and duration of the cold shock. A polyclonal antibody to the moth hsp 60/63 crossreacted with antigen from the viscera of the 60 kDa protein that was expressed during recovery from cold shock. This crossreaction with C. v. sonorensis suggests that the 60 kDa protein expressed during recovery from cold shock in the midge is immunologically related to the moth heat shock protein (hsp). Weather records from central Wyoming suggest that if the stress proteins produced by C. v. slmorensis enhance survival of the earliest, normally lethal temperatures (e,g., -5°C), populations of these insects can persist for an additional 20-30 d in an average year and thus extend the time they can transmit bluetongue virus, coMe BIOCHEM PHYSIOL 113B, 1:73--77, 1996. KEY WORDS, Stress proteins, cold shock, heat shock, Cullicoides variipennis