Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/21617
Type: Artigo de periódico
Title: Effect of sequential heat and cold shocks on nuclear phenotypes of the blood-sucking insect, Panstrongylus megistus (Burmeister) (Hemiptera, Reduviidae)
Author: Garcia, Simone L
Pacheco, Raquel M
Rodrigues, Vera LCC
Mello, Maria Luiza S
Abstract: Thermal shocks induce changes in the nuclear phenotypes that correspond to survival (heterochromatin decondensation, nuclear fusion) or death (apoptosis, necrosis) responses in the Malpighian tubules of Panstrongylus megistus. Since thermal tolerance increased survival and molting rate in this species following sequential shocks, we investigated whether changes in nuclear phenotypes accompanied the insect survival response to sequential thermal shocks. Fifth instar nymphs were subjected to a single heat (35 or 40°C, 1 h) or cold (5 or 0°C, 1 h) shock and then subjected to a second shock for 12 h at 40 or 0°C, respectively, after 8, 18, 24 and 72 h at 28°C (control temperature). As with specimen survival, sequential heat and cold shocks induced changes in frequency of the mentioned nuclear phenotypes although their patterns differed. The heat shock tolerance involved decrease in apoptosis simultaneous to increase in cell survival responses. Sequential cold shocks did not involve cell/nuclear fusion and even elicited increase in necrosis with advancing time after shocks. The temperatures of 40 and 0ºC were more effective than the temperatures of 35 and 5ºC in eliciting the heat and cold shock tolerances, respectively, as shown by cytological analysis of the nuclear phenotypes. It is concluded that different sequential thermal shocks can trigger different mechanisms of cellular protection against stress in P. megistus, favoring the insect to adapt to various ecotopes.
Subject: heat shock
cold shock
sequential shocks
nuclear phenotypes
Panstrongylus megistus
Editor: Instituto Oswaldo Cruz, Ministério da Saúde
Rights: aberto
Identifier DOI: 10.1590/S0074-02762002000800008
Address: http://dx.doi.org/10.1590/S0074-02762002000800008
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02762002000800008
Date Issue: 1-Dec-2002
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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