Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/96054
Type: Artigo
Title: Effect of heavy metals on chromatin supraorganization, nuclear phenotypes, and survival of Triatoma infestans
Title Alternative: L'effet des métaux lourds sur l'organisation supérieure de la chromatine, les phénotypes nucléaires et la survie de Triatoma infestans Klug (Hemiptera, Reduviidae)
Author: Mello, Maria Luiza S.
Kubrusly, Flávia S.
Randi, M. A. F.
Rodrigues, Vera Lúcia C. C.
Ferraz Filho, A.N.
Abstract: The nuclear phenotypes and survival of the hemipteran, Triatoma infestans (Hemiptera, Reduviidae), were studied in specimens treated with copper sulfate and methylmercury. The objective was to determine whether changes in chromatin supraorganization and insect survival similar to those promoted by other stressing agents could also be induced by heavy metals. At the concentrations used, copper sulfate and methylmercury were toxic to the cells, mainly inducing nuclear degenrration in the Malpighian tubules and being lethal to a large part of the insect population. Although some individual resistance was found, especially in fasted specimens, heavy metals were found to be much more lethal than was, for instance, a thermal shock at 0°C for 12 h. The nuclear phenotypes detected after heavy metal treatment were similar to those reported under other stressing conditions. However, the frequency at which nuclei exhibited aspects of heterochromatin unraveling was much higher than that found in fasted and thermal-shocked specimens, and was independent of the heavy metal type used. If this phenotype represents an attempt to improve opportunities for extensive cell and insect survival, it was not sufficiently effective. In 5th instar nymphs, the effect of CuSO4 on chromatin supraorganization was detected at early steps of spermatogenesis but not in the cells which were at late spermiogenesis when the metal was administered. This is probably due to changes in nuclear protein composition and to the tightly packed state of the DNA-protein complexes occurring at spermiogenesis, which may protect chromatin from damages. However, when CuSO4 was supplied to 4th instar nymphs, it slowed down the spermiogenesis process, possibly due to several factors including Cu2+ binding to DNA phosphates. © 1995 Kluwer Academic Publishers.
The nuclear phenotypes and survival of the hemipteran, Triatoma infestans (Hemiptera, Reduviidae), were studied in specimens treated with copper sulfate and methylmercury. The objective was to determine whether changes in chromatin supraorganization and insect survival similar to those promoted by other stressing agents could also be induced by heavy metals. At the concentrations used, copper sulfate and methylmercury were toxic to the cells, mainly inducing nuclear degenrration in the Malpighian tubules and being lethal to a large part of the insect population. Although some individual resistance was found, especially in fasted specimens, heavy metals were found to be much more lethal than was, for instance, a thermal shock at 0°C for 12 h. The nuclear phenotypes detected after heavy metal treatment were similar to those reported under other stressing conditions. However, the frequency at which nuclei exhibited aspects of heterochromatin unraveling was much higher than that found in fasted and thermal-shocked specimens, and was independent of the heavy metal type used. If this phenotype represents an attempt to improve opportunities for extensive cell and insect survival, it was not sufficiently effective. In 5th instar nymphs, the effect of CuSO4 on chromatin supraorganization was detected at early steps of spermatogenesis but not in the cells which were at late spermiogenesis when the metal was administered. This is probably due to changes in nuclear protein composition and to the tightly packed state of the DNA-protein complexes occurring at spermiogenesis, which may protect chromatin from damages. However, when CuSO4 was supplied to 4th instar nymphs, it slowed down the spermiogenesis process, possibly due to several factors including Cu2+ binding to DNA phosphates.
metadata.dc.description.abstractalternative: Les phénotypes nucléaires et la survie de l'hémiptère Triatoma infestans ont été étudiés sur des spécimens traités avec du sulfate de cuivre et du méthyle de mercure. L'objectif a été de déterminer si les changements provoqués par d'autres agents stressants sur l'organisation supérieure de la chromatine et la survie de l'insecte peuvent être induit aussi par les métaux lourds. Il est apparu qu'aux concentrations utilisées, le sulfate de cuivre et le méthyle de mercure sont toxiques pour les cellules, provoquent principalement une dégénération nucléaire dans des organes tels que les tubes de Malpighi, et sont léthaux pour une grande partie de la population. Bien qu'une certaine résistance individuelle ait été trouvée particulièrement chez les spécimens à jeun, les métaux lourds se sont révélés beaucoup plus léthaux que, par example, un choc thermique de 12 h à 0 °C. Les phénotypes nucléaires observés après traitement aux métaux lourds sont similaires à ceux décrits dans d'autres conditions stressantes. Toutefois, la fréquence avec laquelle les noyaux ont montré des aspects déroulés de l'hétérochromatine a été beaucoup élevée que chez les spécimens soumis au jeun ou à un choc thermique, quelque soit le métal utilisée. Si ce phénotype correspond à une tentative d'amélioration de la survie de la cellule et de l'insecte, cela n'est pas suffisant. Chez les nymphes au 5e. étage, l'effet du sulfate de cuivre sur l'organisation supérieure de la chromatine a été observé dès les premières étages de la spermatogenèse, mais pas sur les cellules qui se trouvaient en spermiogenèse avancée lorsque le métal fut fourni. Cela est probablement dû à des changements dans la composition protéinique du noyaux et à la structure dense des complexes ADN‐protéines lors de la spermiogenèse, qui protégerait la chromatine. Toutefois, ce même métal, fourni à des nymphes au 4e étage, relentit la spermiogenèse, probablement à cause de facteurs diverses, inclusivement son attachement avec les phosphates de l'ADN.
Subject: Cobre
Mercúrio
Cromatina
Análise de sobrevida
Triatoma infestans
Hemiptera
Country: Holanda
Editor: Kluwer Academic
Citation: Entomologia Experimentalis Et Applicata. Kluwer Academic Publishers, v. 74, n. 3, p. 209 - 218, 1995.
Rights: fechado
Identifier DOI: 10.1111/j.1570-7458.1995.tb01893.x
Address: https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1570-7458.1995.tb01893.x
Date Issue: 1995
Appears in Collections:IB - Artigos e Outros Documentos

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