Changes in nuclear phenotypes following cold shock in Panstrongylus megistus (Burmeister)

Abstract

The nuclear phenotypes of Malpighian tubule epithelial cells of 5th instar male nymphs of the bloodsucking insect

Changes in nuclear phenotype frequencies following sequential cold shocks in Triatoma infestans (Hemiptera, Reduviidae)

“…A and NE are forms of cell death with typical morphological aspects in the Malpighian tubules of reduviids (Dantas & Mello 1992, Mello et al 1995, Garcia et al 2000a. In our study, the incidence of A was low, especially following sequential cold shocks, and was independent of the number and duration of shocks, of the interval at 30ºC between shocks, and of the nutritional state.…”

“…HD was not a significant surviving strategy following cold shocks. Indeed, HD is not required for cell survival following cold shocks in T. infestans, in contrast to Panstrongylus megistus, a reduviid species which is more sensitive to cold shock and acquires cold-shock tolerance following sequential cold shocks (Garcia et al 1999(Garcia et al , 2000a.…”

Effect of sequential heat and cold shocks on nuclear phenotypes of the blood-sucking insect, Panstrongylus megistus (Burmeister) (Hemiptera, Reduviidae)

“…With the exception of the normal phenotype, the other phenotypes are more frequent in specimens subjected to heat and cold shocks (Garcia et al 2000a, b). The frequency of fused nuclei and of nuclei with heterochromatin decondensation compared with that of other phenotypes was considered insufficient to cope with the deleterious effects of a severe heat shock (Garcia et al 2000a). For the response to cold shock, the activation of nuclear and cell fusion which generates giant nuclei was found to be less effective or necessary than that elicited by heat shock (Garcia et al 2000b).…”

“…Giant nuclei are characterized by a bigger size when compared with normal nuclei, and originate from nuclear and/or cellular fusion (Wigglesworth 1967, Mello & Raymundo 1980. This phenotype has been described as a possible mechanism of cellular and organ protection under unfavourable conditions in blood-sucking insects (Wigglesworth 1967, Mello & Raymundo 1980, Dantas & Mello 1992, Garcia et al 2000a. Apoptosis and necrosis are defined in terms of their morphological characteristics (Kerr 1971, Kerr et al 1972, Garcia et al 2000a.…”

“…This phenotype has been described as a possible mechanism of cellular and organ protection under unfavourable conditions in blood-sucking insects (Wigglesworth 1967, Mello & Raymundo 1980, Dantas & Mello 1992, Garcia et al 2000a. Apoptosis and necrosis are defined in terms of their morphological characteristics (Kerr 1971, Kerr et al 1972, Garcia et al 2000a. With the exception of the normal phenotype, the other phenotypes are more frequent in specimens subjected to heat and cold shocks (Garcia et al 2000a, b).…”