NATH, B. B., and LAKHOTIA, S. C. 1989. Heat-shock response in a tropical Chironomus: seasonal variation in response and the effect of developmental stage and tissue type on heat shock protein synthesis. Genome, 32: 676-686. Examination of heat shock induced transcriptional activity in salivary gland polytene nuclei of a tropical Chironomus, C. striatipennis, revealed nine heat-shock puffs. In 24°C-reared larvae optimal heat-shock response was seen at 39"C, while a 41°C shock was nearly lethal. In a population grown under natural conditions of seasonal variations, the heat-shock response was dependent upon the current ambient temperature. In summer months, response to 39°C was variable, from complete to no induction of heat-shock puffs in different cells. In control glands from larvae growing at 33 -36°C in summer, heat-shock genes were not active, although in 24°C-reared larvae, 33°C already caused partial induction. Unlike the 24°C-reared population, a 41 "C shock to summer larvae was not lethal.[35S]Methionine-labelled protein synthesis pattern in the summer larvae revealed appreciable accumulation of heat-shock polypeptides in control glands, which possibly autoregulates their further induction and also explains the better thermotolerance of these larvae. In a developmental study of a 24°C-reared population, some heat-shock polypeptides were found to be commonly synthesized at 39°C in all the tissues (salivary glands of larvae; Malpighian tubules of larvae, pupae, and adult; adult ovaries), while other heat-shock polypeptides showed apparent tissue and (or) developmental stage specificity. Heat shock protein 70 was most abundantly synthesized in all the tissues examined.NATH, B. B., et LAKHOTIA, S. C. 1989. Heat-shock response in a tropical Chironomus: seasonal variation in response and the effect of developmental stage and tissue type on heat shock protein synthesis. Genome, 32 : 676-686. L'examen des activitks transcriptionnelles induites par des chocs thermiques dans les noyaux de la glande salivaire d'un Chironomus, le C. striatipennis, a rkvklk la prksence de neuf renflements causes par des chocs thermiques. Chez des larves soumises 8 une tempkrature d'klevage de 24"C, la rkponse 8 une tempkrature choc optimale a kt6 vue 8 39"C, alors qu'une tempkrature de 41 "C s'est avkrke presque lktale. Chez une population croissant dans des conditions naturelles de variations -saisonni&res, la rkponse aux chocs therrniques a varik selon les tempkratures ambiantes. En ktk, la rkponse 2 une tempkrature de 39°C a varik depuis l'absence d'induction 8 une induction complkte de renflements dans diffkrentes cellules. Dans les glandes tkmoins de larves croissant 8 33-36°C en ktk, les g&nes de chocs thermiques n'ont pas kt6 actifs tandis que chez les larves klevkes 8 24"C, une tempkrature de 33°C causait dkj8 une induction partielle. Contrairement aux populations klevks 8 24"C, la tempkrature de 41 "C ne s'est pas avkrke lktale pour les larves d'ktk. Le profil de synth&se de protkines marqukes 8 la mkthionine [S35] chez les l...