Том 50, № 2 (2019)

The emergence of cells with pathological mitosis and the deviation from diploidity in the meristematic tissue of experimental plants of the genus Vitis (Tournef.) Linn. obtained from stenospermocarpic seeds was evaluated. The grape plants obtained from crossing seedless varieties with seedless and seed pollinators were the material for cytogenetic research. A total of 11 crosses were made. The cytogenetic analysis was carried out according to the recommended methods for fruit crops and grape. A total of 11 039 cells were examined. The pathology of mitosis in the cells of grape plants in vitro was observed, in particular, a hollow metaphase, a three-group metaphase and a metaphase with polar chromosomes as well as haploid, triploid, and tetraploid cells. The total frequency of abnormal cells was 0.15. The pathology of mitosis is observed in meristematic tissue of grape varieties as well. The evaluation of emergence of mitotic anomalies in the meristematic tissue of plants was carried out. The correspondence between the actual distribution of the anomalies in experimental populations and the theoretical distribution, as well as the degree of their relative habit to populations, the indices of absolute, relative, and intrapopulation diversity, was determined. As a result of the study of the polyembrionic hybrid offspring of grapes, differentiation in the equitability of distribution and habit of five mitotic anomalies to 11 populations was revealed, and differences between experimental populations by diversity were detected. The maximum degree of relative diversity of populations reached a value of 0.503. In general, the low relative diversity indicates a lack of complete equalization of anomalies by the presence in the populations.

Expression of cystathionine β-synthase (CBS) in the brain of adult trout under normal conditions and 1 week after an eye injury was assessed using Western blot analysis. The study of CBS distribution in the brain of intact trout and after a mechanical eye injury in the telencephalon, tectum, cerebellum, and brainstem was carried out by the method of immunoperoxidase labeling on free-floating sections. The results of the study showed an increase in CBS expression in different brain divisions after an eye injury. In the visual projection center of the brain (tectum), radial glia cells expressing CBS were revealed after the injury. The emergence of CBS+ heterogeneous radial glia in the trout tectum after eye injury indicates the ability of the reactive neural stem cells (NSC) to synthesize hydrogen sulfide. CBS+ fibers and cells were found in the proliferative zones of cerebellum (valvula) and telencephalon (ventral region). In the intact trout tegmentum, CBS expression was observed in large neurons of the dorsal region and in the proliferative zones. After the eye injury, reactive neurogenic niches appeared in the brainstem, and no CBS-immunopositivity was detected in the periventricular zone. The increased expression of H₂S-producing CBS enzyme after a traumatic impact can probably be explained by the neuroprotective functions of hydrogen sulfide, which are implemented in the matrix zones of the brain associated with reparative neurogenesis. A cultivation of trout brain cells showed the formation of neurosphere-like complexes, a part of which exhibited CBS-immunopositivity in the monolayer.

For comparative analysis of the chronology and dynamics of development and differentiation of germ cells in human gonads in antenatal and postnatal periods, we analyzed the composition of somatic cells as well as the amount, morphology, and characteristics of the state of nuclear chromatin on the basis of the ratio of mitotic stages and prophase I of meiosis in oocytes and spermatocytes. Until week 6 of antenatal development, human gonads are classified into the indifferent type; the proportion of germ cells (GCs) in the sum of somatic and germ cells in them ranged from 9.21 to 33.29%. In the analysis of histological preparations, gonads of female fetuses on week 8–9 of antenatal development were significantly differentiated as ovaries. The formation of the pool of female germ cells is ensured by the proliferation of oogonia (1.96–10.34% of mitoses) in embryogenesis and by degeneration of their nuclei. In developing testes, among the nuclei of male germ cells of antenatal and neonatal gonads, nuclei at the leptotene stage of prophase I of meiosis and at subsequent stages were not detected. In the gonads of male fetuses on weeks 6–11 of antenatal development, mitotic and degenerating germ cells and germ cells at the preleptotene stage of chromosome condensation were detected, whereas no mitotic germ cells were identified in the histological preparations of testes of male newborns and infants. An important distinction between the chronology of differentiation of gametes and chromatin transformation dynamics in the nuclei of male and female germ cells is the lack of the chromatin decondensation phase (prochromosomes) at the preleptotene stage in prophase I of meiosis in the male germ cells.