Heat shock-induced apoptosis in germ line cells of Triatoma infestans Klug

The survival of Triatoma infestans and of somatic cells from this species i s affected by heat shock. In this study, we examined the cell death respons es of male germ line cells from 5th instar nymphs 7 and 30 days after heat shock exposure (40 degrees C, 1 h). The preparations were stained by the Fe ulgen reaction and the TUNEL immunocytochemical assay. Apoptosis was elicit ed by heat shock, with positive TUNEL responses in spermatogonial chromatin and chromosomes, spermatids and sperm cells. Spermatogonia were most affec ted seven days after the shack whereas some spermatids and sperm cells exhi bited DNA fragmentation only thirty days after heat shack. The rate of cell death varied among the cells. In some cases, cellular differentiation was unaffected by heat shock, with DNA fragmentation occurring towards the end of spermatogenesis.