Efeitos de choques de temperatura sobre fenotipos nucleares de Triatoma infestans Klug, em condições de insetario da SUCEN de Mogi-Guaçu, S.P

AUTOR(ES)
DATA DE PUBLICAÇÃO

1990

RESUMO

Fourth instar nymphs of the hemiptera Triatoma infectas Klug were submitted to thermal shocks at 0°C and 40°C for 1 and 12 hours, being sacrificed from 10 minutes to 2hours after the shock treatment for cyltological analysis of their . Malpighian tubules. The objective was to investigate if this type of stress would promote alterations 1n the nuclear phenotype. Nymphs which had been returned to the control conditions (300C) for 3 days and 1 month after the shock treatment, were analized in the same way In add it ion, the relative frequencies of the nuclear phenotypes of epithelial cells of the Malpighian tubules in each individual were determined, and at the same time the influence of the stress agent on the survival and moulting of the insect under study during a 30-da!::l period. It was found that not only the same phenotypes observed 1n the control material (nuclei with 1, 2 and several chromocentres) appeared. but also vacuolized. giant, picnotic nuclei, and with the chromocenters partially or completely unravelled. Between individuais of the same group, considerable variation in the reaction to stress was noted with respect to types and frequencies of the nuclear phenotypes. When compared between themselves. Considerable variation appeared in the different ewperiments considered. With respect to the survival and moulting index of the insects analized during the 30-day post shock period, alterations in nymphal development were observed in alI the experimental conditons studied, reducing the frequency of moulting as compared to the control, and in the case of shock at 400C, the speed of progress10n of this processo However, only 12 hours of hypothermal shock induced a measurable drop in the survival curve of these insects. With respect to chromatin unravelling, suggested in some cases due to the appliction of stress, it was shown that heterochromatic areas, when uncompacted, presented free phosphate groups of the DNA, available for binding to toluidine blue, but not to clupeine. This could be a consequence of possible transcriptional activity induced by the thermal shock

ASSUNTO(S)

citologia

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