Analysis of Nucleoli in Intact Lymphocytes in Different Mammalian Species and Hybrids

The purpose of this study was to develop methods for quantitative and qualitative assessment of the activity of the nucleolus using the color intensity of argyrophilic regions and to study the effect of the species feature on the quantitative and qualitative indicators of the nucleoli and nucleolus organizer regions. The experiment involved Ovis aries (n = 40), hybrids of domestic sheep and argali (n = 10), Capra hircus (n = 32), Myocastor coypus (n = 25) and the American mink Neogale vison (n = 20). To characterize the activity of the nuclear apparatus of interphase cells, the number of argyrophilic zones in the AgNOR cell was determined; the total area of the nucleoli ΣSNOR expressed in logical units, and the color intensity of the nucleus and its various regions in logical units. Microsoft Excel-2010 software was used to process the obtained primary digital materials and the SPSS v.23.0 software package was used for statistical processing. The number of nucleolus organizer regions, depending on the species and individual characteristics, in representatives of the genus Ovis varied from 0 to 9 and averaged 3.07±0.19 NOR per cell, in the genus Capra 2.74±0.12. The maximum number of NOR in the interphase cells of lymphocytes of the studied population of a domestic goat was 8, the minimum number was the absence of visualized NOR. The coefficient of variation of the number of NOR in this population was 52%. In the interphase lymphocytes of the American mink, the frequency of occurrence of NOR averaged 0.84±0.01, the maximum number was 4, the minimum number was the absence of visible crossed NOR, in nutria, it was 0.63±0.01 and 2.0, respectively. The minimum value of the indicators characterizing the parameters of the nucleolar area and the color density of argyrophilic zones (DNOR) was established by Myocastor coypus. The results of the study show that one of the main factors affecting the parameters of the nucleolus is the specific feature of the organism.