Effect of Sequential Cold Shocks on Survival and Molting Incidence in Panstrongylus megistus (Burmeister) (Hemiptera, Reduviidae)

Garcia, S.; Garcia, Nancy L.; Rodrigues, Vera; Mello, Maria Luiza S.

doi:10.1006/cryo.2001.2301

Cited by 14 publications

(13 citation statements)

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“…Cold shock tolerance, also demonstrated in P. megistus in terms of increased specimen survival and molting rates after sequential cold shock assays (Garcia et al 2001a), was equally accompanied by changes in frequency of specific cell nuclear phenotypes. However, the frequency of these changes were not always the same as those observed after sequential heat shocks.…”

Section: Discussionmentioning

confidence: 73%

“…A more drastic change in temperature from 28 to 0 o C revealed a reduced ability or need of the cells to cope with this condition when examining the decrease in frequency of heterochromatin decondensation in relation to that promoted when the 1st shock was given at 5 o C. However, this difference in frequency of nuclear phenotypes did not affect the insect survival rate (Garcia et al 2001a).…”

Section: Discussionmentioning

confidence: 96%

“…Prolonged cold and heat shocks are deleterious to P. megistus nymphs (Garcia et al 1999), but resistance to these stressing conditions can be elicited following sequential shocks in which a mild shock precedes a severe one (Garcia et al 2001a, b). Heat-shock tolerance follows a pattern typical of heat shock protein activation (Garcia et al 2001a). Coldshock tolerance also presumably involves heat shock proteins, although consideration of other protective mechanisms has not been eliminated (Garcia et al 2001b).…”

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

Garcia

Pacheco

Rodrigues³

et al. 2002

Mem. Inst. Oswaldo Cruz

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Section: Discussionmentioning

confidence: 73%

Section: Discussionmentioning

confidence: 96%

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confidence: 99%

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

Garcia

Pacheco

Rodrigues³

et al. 2002

Mem. Inst. Oswaldo Cruz

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“…However, the synthesis of heat-shock proteins during the cold-shock tolerance response has been suggested for P. megistus (Garcia et al 2001a Since no generalization can be made about the responses of different species of the same family to temperature shocks (Clark & Fucito 1998), and since T. infestans and P. megistus differ from each other in several aspects, including their responses to heat and cold shocks, it is possible that T. infestans may respond differently to sequential cold shocks compared to P. megistus. This response may be affected by the state of nourishment of the insects (Garcia et al 1999).In the present study, survival and molting incidence were investigated in T. infestans after sequential cold shocks under different conditions of nourishment and the responses compared to those of P. megistus (Garcia et al 2001a). …”

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confidence: 99%

“…In the present study, survival and molting incidence were investigated in T. infestans after sequential cold shocks under different conditions of nourishment and the responses compared to those of P. megistus (Garcia et al 2001a).…”

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Effect of Sequential Cold Shocks on Survival and Molting Rate in Triatoma infestans Klug

Campos

Rodrigues²,

Wada

et al. 2002

Mem. Inst. Oswaldo Cruz

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Key words: Triatoma infestans -nutritional conditions -cold-shock tolerance -survival -molting rateThe survival, molting incidence and chromatin supraorganization of Triatoma infestans and Panstrongylus megistus, blood-sucking hemipteran vectors of Chagas disease, are affected by stressing agents, including heat and cold shocks (Rodrigues et al. 1991, Dantas & Mello 1992, Mello et al. 1995, Garcia et al. 1999, 2000. These insect species differ in nuclear characteristics (Mello 1971, 1975, Mello et al. 1986) and in their response to heat and cold shocks (Rodrigues et al. 1991, Garcia et al. 1999, with P. megistus being less resistant to prolonged heat (40 o C) and cold (0 o C) shocks than T. infestans (Rodrigues et al. 1991, Garcia et al. 1999.Thermotolerance following sequential heat shocks and tolerance to sequential cold shocks (i.e., an acquired increase in survival and molting incidence) have been reported in P. megistus (Garcia et al. 2001a,b). Cold-shock tolerance in insects has been suggested to involve the synthesis of heat-shock or other proteins, as well as the presence of cryoprotectants and improved use of metabolic energy resources (Clark & Fucito 1998). There is no evidence of cryoprotectant use in blood-sucking hemipterans. However, the synthesis of heat-shock proteins during the cold-shock tolerance response has been suggested for P. megistus (Garcia et al. 2001a Since no generalization can be made about the responses of different species of the same family to temperature shocks (Clark & Fucito 1998), and since T. infestans and P. megistus differ from each other in several aspects, including their responses to heat and cold shocks, it is possible that T. infestans may respond differently to sequential cold shocks compared to P. megistus. This response may be affected by the state of nourishment of the insects (Garcia et al. 1999).In the present study, survival and molting incidence were investigated in T. infestans after sequential cold shocks under different conditions of nourishment and the responses compared to those of P. megistus (Garcia et al. 2001a). MATERIALS AND METHODSFifth instar nymphs of T. infestans Klug (Hemiptera, Reduviidae) reared at 30 o C and 80% relative humidity in the laboratory at Sucen (Mogi-Guaçu, SP) were used. The insects fed once a week on hen blood. Some specimens were fasted for up to 15 days before and up to 30 days after the shocks.Immediately after a shock at 0 o C for 1 h, the nymphs were returned to control conditions and 8 h and 24 h later were subjected to a second shock at 0 o C which lasted 12 h. The temperature of 0 o C was chosen based on a previous report (Rodrigues et al. 1991).Nymphs maintained at 30 o C, a temperature traditionally used for rearing T. infestans in the insect facilities at Sucen since 1980 (Rodrigues et al. 1991)(control #1), as well as nymphs subjected to a single shock at 0 o C for 1 h (control #2) and 12 h (control #3) were used as controls.After the shocks, the nymphs were returned to the control temperature (30 o C) and monitored ...

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Histone acetylation and methylation marks in chromatin of Panstrongylus megistus (Hemiptera, Reduviidae)

et al. 2018

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Panstrongylus megistus, a potential vector of Chagas disease, currently occupies a wider geographic distribution in Brazil than Triatoma infestans, another member of the hemipteran Reduviidae family and a vector of the same disease. A small heterochromatic body (chromocenter) formed by the Y chromosome is evident in the somatic cells of P. megistus, differing in size and chromosome type contribution from the well-studied chromocenters present in T. infestans. While the overall distribution of histone epigenetic marks differ when comparing the heterochromatin and euchromatin territories in T. infestans, no similar data have been established for other hemipteran reduviids, including P. megistus. In the present work, histone acetylation and methylation marks were investigated in cells of Malpighian tubules of P. megistus 5th instar nymphs using immunocytochemical assays and compared to previously published data for T. infestans. Although similarities between these species were found regarding absence of acetylated H3K9, H4K8 and H4K16, and H3K9me and H3K9me in the chromocenter, presence of these marks in euchromatin, and presence of H3K9me in the chromocenter, no intimate association of acetylated H4K8 and 18S rDNA was revealed in the chromocenter of P. megistus. The elevated abundance of H3K9me marks at the nuclear periphery in P. megistus cells, differing from data for T. infestans, is suggested to reflect differences in the interaction of lamina-associated chromatin domains with the nuclear lamina, methyl-transferase modulation and/or association with the last DNA endoreplication step in 5th instar nymphs, which is a matter for further investigation.

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Effect of Sequential Cold Shocks on Survival and Molting Incidence in Panstrongylus megistus (Burmeister) (Hemiptera, Reduviidae)

Cited by 14 publications

References 7 publications

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

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

Effect of Sequential Cold Shocks on Survival and Molting Rate in Triatoma infestans Klug

Histone acetylation and methylation marks in chromatin of Panstrongylus megistus (Hemiptera, Reduviidae)

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