Vol 46, No 1 (2019)

In this paper, the role of the Wnt/β-catenin pathway in the establishment of the body plan in multicellular animals has been analyzed. We demonstrated that at different stages of development the Wnt signaling cascade is involved in several directly unrelated processes such as inner germ layer specification, anterior–posterior axis patterning, and terminal growth. Bioinformatics analysis revealed the independent divergence of Wnt ligands in basal Metazoa and conservation of Wnt subfamilies within the Cnidaria + Bilateria clade. Polarized expression of Wnt ligands in sponge and annelid larvae has been shown, thus confirming the applicability of the existing model of the main body axis patterning to two more taxa. The β-catenin localization and inhibitory analysis have provided evidence of the unlikely role for Wnt pathway in endomesoderm determination in nereid polychaetes. The evolutionary trend to establish alternative mechanisms even for key events such as segregation of germ layers has been observed in the case of more determinative ontogeny and predominance of autonomous specification, as exemplified by the heteroquadrant (unequal) type of spiral development.

It is demonstrated in this study that a decrease in the rate of irreversible age-related thymus atrophy affects animal longevity. It was observed that the life span of rats may be increased by thymus transplantation from young animals into the immune privileged regions of ageing rats. It has been shown that the season of birth has effects on animal longevity, namely, rats born in the spring–summer period live shorter lives than those born in autumn or winter.

The possibilities of using the concept of ontogeny polyvariance in evolutionary morphology are considered. The concept is aimed at identifying the full range of options associated with various aspects concerning the organization of living organisms. In conjunction with the analysis of the correlation structure of traits and methods of population meronomy, the proposed approach can help to elucidate the modus of the evolution of structural diversity.

The biomorphological diversity of riverside and aquatic herbaceous plants represented mainly by annual and biennial plants of vegetative origin, which replace perennial and biennial plants and annual, biennial, and winter monocarpics, has been studied. Depending on the season and moisture conditions, some species are represented by different basic biomorphs and phenobiomorphs. The modes of morphological evolution have been determined at the levels of individuals (abbreviations), shoots and their parts (abbreviations and the corresponding prolongations), and roots (prolongations). The role of the developmental features of monocarpic shoots in the habitat specificity of annual and biennial plants of vegetative origin has been described.

This study is focused on the role of the canonical Wnt-signaling pathway in morphogenesis and regeneration of the adrenal cortex in rats exposed to the endocrine disruptor dichlorodiphenyltrichloroethane (DDT) during prenatal and postnatal development. Hypoplasia of the zona glomerulosa and, to a greater extent, of the zona reticularis was associated with suppression of canonical Wnt. This data indicates the role of the Wnt-signaling pathway in the development of the zona reticularis. Circulatory disorders in the adrenal cortex led to focal necrosis of the zona fasciculata and subsequent activation of cell proliferation and regeneration, mediated by the inhibition of the canonical Wnt in it. Thus, the disturbance of activation of the canonical Wnt-signaling pathway can be considered as a mechanism of the disrupting effect of DDT in postnatal development.

The content of the total lipids, including structural and storage, and fatty acids (FAs) was evaluated in the liver and gonads of females of the three-spined stickleback Gasterosteus aculeatus from different spawning grounds of the White Sea: in Sel’dyanaya Inlet and Kolyushkovaya Lagoon (Kandalaksha Bay), and in Konyukhov Bay (Onega Bay). The content of total lipids in the gonads was high (from 14.25 to 20.05% of dry weight); while significant differences in their content, as well as in the quantitative profile of the main lipid classes, may indicate differences in the spawning peculiarities. In the gonads, the amount of the structural phospholipids was different, but the most pronounced variations were registered in the content of the reserve triacylglycerols and their components, in particular, two essential polyunsaturated FAs (22:6n-3, docosahexaenoic, and 20:5n-3, eicosapentaenoic), and a monounsaturated FA (16:1n-7, palmitoleic). In the gonads of the fish sampled in Konyukhov Inlet, the highest level of reserve triacylglycerols and palmitoleic acid was registered; this can positively affect the body weight and viability of the coming embryos. The increased content of physiologically significant n-3 polyenic FA (22:6n-3 and 20:5n-3) in the gonads of the stickleback females at this stage of the reproductive cycle may be associated with increased need for these acids by the coming embryos.

The abundance, ratio of ecologo-trophic groups of microorganisms, microbial biomass, and predominant members of the taxonomic composition of microbial complexes are indicators of the different ecological states of soils of the central floodplain and islands of the upper delta of the Selenga River under arid conditions. The highest coefficients of oligotrophy with an increased share of microorganisms growing on the nitrogen-free Ashby medium, as well as predominance of Arthrobacter bacteria, were determined in low-moistened soils of the islands. In general, low microbiological activity (in comparison with the soils of the central floodplain depressions), resulting from a lack of moisture, is observed in these soils despite the uncontrolled cattle grazing in the areas of the latter.

A review of our own data and published material on the screening pigments of the eyes of vertebrates and invertebrates and the human eye, i.e., melanosomes and ommochromes, is presented. The role of these pigments in the vision of vertebrates and invertebrates as antioxidant organelles is considered, as is the role of melanosomes in the physiology, aging, and pathology of the human eye.