Analysis of chromatin and nuclear area alterations in triatomines during starvation

In the present study changes in nuclear area and chromatin distribution in the Malpighian tubules of a blood-feeding insect, the vector of Chagas' dis ease, were analysed. Male and female adult insects were dissected, after a starving period of up to 28 days. The Malpighian tubules were fixed and sta ined by orcein lacto-acetic. The nuclei were analyzed by photomicrography, karyometry and a statistical analysis was performed. It was observed that w ith the increase of the starvation period there were alterations in the nuc lear phenotype, that is, changes in the nuclear area and chromatin extenuat ion. In males, starting from the second week of starvation, chromatin exten uation was accentuated, and the beginning of nuclear coalition occurred mor e frequently in the third and fourth starvation weeks. In females, the acce ntuated chromatin extenuation was observed after the third starvation week, and irregularities in nuclear borders were more frequent. The descriptive statistical analysis of the male and female nuclear areas revealed that the nuclear areas continued to increase during starvation, reaching highest va lues in the third week. Another outstanding aspect is that in the third sta rvation week karyometry presented larger heterogeneity with higher standard deviation values for both genders. Therefore, nuclear alterations related to the distribution and extenuation chromatin and increase in nuclear area were observed. These aspects suggest the presence of nuclear metabolic mech anisms that lead to synthesis of specific proteins necessary for the protec tion and maintenance of the cell during physiologic stress.