Nuclear phenotype changes after heat shock in Panstrongylus megistus (Burmeister)

The nuclear phenotypes of Malpighian tubule epithelial cells of male nymphs of the blood-sucking insect, Panstrongylus megistus, subjected to short- a nd long-duration heat shock at 40 degrees C were analyzed immediately after the shock and 10 and 30 days later: No, mal nuclei with a usual heterochro matic body as well as phenotypes indicative of survival (unravelled heteroc hromatic, giants) and death (apoptosis, necrosis) responses were observed i n control and treated specimens. However all nuclear phenotypes, except the normal ones, were more frequent in shocked specimens. Similarly altered ph enotype pes have also been reported in Triatoma infestans following heat sh ock, although at different frequencies. The frequency, of the various nucle ar phenotypes observed in this study suggests that the forms of cell surviv al observed were not sufficient or efficient enough to protect all of the M alpighian following cells from the deleterious effects of stress. In agreem ent with studies on P. megistus survival following heat shock, only long-du ration shock produced strongly deleterious effects.