No 3 (2025)

The expression of genes encoding transcriptional myogenic regulatory factors (MRF) in muscles, and the activity of enzymes involved in energy and carbohydrate metabolism in the liver and muscles of rainbow trout Oncorhynchus mykiss Walb., grown under 24-hour lighting and fed at night in aquaculture conditions in one of the southern regions of the Russian Federation for seven months, were studied. The results of the study showed that this regime, introduced into the standard technology of trout growing, had a beneficial effect on its condition and growth. By the end of the study, trout individuals grown under the experimental regime differed from the control variants in having higher expression levels of the MRF genes (myod1, myf5, mlc2, mstn1a) and increased activity of pyruvate kinase and cytochrome c oxidase in the liver. It can be assumed that the introduction of additional lighting and feeding at night into the technology of trout cultivation stimulates aerobic metabolism, promotes the intensification of muscle growth processes in trout individuals and, in general, has a positive effect on the fish organism condition.

Amino acid sequence polymorphism of cytochrome b enzyme isoforms in 16 samples of Alexandromys oeconomus from the North-East Asia and one sample from Alaska was studied. Forty-three variants of the polypeptide differing among themselves by 33 amino acid substitutions in 30 sites were detected. The distribution of polypeptide isoforms in the samples was determined. The phylogenetic relationships of haplotypes encoding the most common variants of the enzyme were examined. Molecular diversity indices of synonymous haplotypes were determined. Localisation of amino acid substitutions in the spatial configuration of the enzyme was found. The substitutions (nucleotide – T997C and amino acid – F333L), claiming to be genetic markers of the Beringian haplogroup of A. oeconomus, were discovered.

For Central Yakutia the data on the distribution and ecology of rare aquatic species, such as Hydrilla verticillata, Potamogeton maackianus, P. rutilus and protected species, such as Nuphar pumila and Nymphaea tetragona, are summarized. Most occurrences of these species have been found in water-erosion lakes of the valley complex of the Lena, Aldan, and Amga rivers. The combination of microclimate of large river valleys, the presence of taliks, and the hydrological and hydrochemical factors together ensure successful survival of diasporas of these rare species under the conditions of Central Yakutia. All water bodies belong to small lakes, and are situated in river valleys and are at the stage of maturity (old age). Their waters are neutral or slightly alkaline with low mineralization. The ranges of the main ecological parameters of habitats for each species are given. We recommend including Hydrilla verticillata, Potamogeton maackianus, and P. rutilus in the regional Red Data Book with the status 3d (rare species situated on the edge of their range).

The effect of treating Bromopsis inermis (Leyss) seeds with bacteria of the Bacillus subtilis 26D strain and the oil-tolerant B. subtilis 26D⁺ⁿ line on the physiological and biochemical characteristics of plants under conditions of oil pollution of the soil was studied. It was shown that the B. subtilis 26D⁺ⁿ line, under conditions of cultivation of awnless brome plants on oil-contaminated soils, effectively stimulated growth, reducing the development of oxidative stress in tissues, in comparison with the control and plants inoculated with the original strain of B. subtilis 26D. Inducing tolerance to oil pollution of soil in plants using endophytic strains B. subtilis 26D⁺ⁿ may be due to their complex biological activity and adaptation to oil components.

Using material from laboratory colonies, it was established that the variability of deviations from the typical shape (tf) of the anterior lobe M1 in lemmings of the genus Lemmus forms a bilateral morphological module, designated as atypical shape (AF). Three morphotypes of AF have been identified, differing in degree of complexity. The main component of modular variability is an increase in the frequency of individuals with the AF phenotype and the degree of expressiveness of this phenotype with age. Segregation in the offspring into AF and tf individuals in various crossing options does not contradict the hypothesis of monogenic inheritance of these variations. Individuals with the tf phenotype are recessive homozygotes. Sometimes among them there may be undetected heterozygotes. Which phenotype (tf or AF) a heterozygote exhibits may depend on the litter number and (or) on the influence of modifier genes. Dominant homozygotes are considered nonviable.

Composition, diversity and distribution of zooplankton were studied in Fram Strait and in the southern Barents Sea during the winter period. Multivariate analysis revealed a clear separation of the sampling stations based on oceanographic, bathymetric, and food conditions. Two types of zooplankton assemblages were delineated and these corresponded to the two study regions. Copepods dominated by abundance and biomass. Generalized linear models showed a close relationship of the abundance of common zooplankton groups and diversity indices with mean water temperature, salinity, depth, and chlorophyll a concentration. An increase in the proportion of boreal species and in the total biomass suggested Atlantification of marine Arctic zooplankton communities as well as positive impact of warming on the zooplankton development.

It was established, that the eurasian pygmy shrew has a shorter reproductive period than other species of shrews. The reproductive period of the Sorex minutus, starting in from mid-May until end of September, and characterized by the participation of all adults and overwintered individuals in the reproduction of the variety between 2 to 11 embryons, average of 6.0 ± 0.21 (n = 53). This amount of embryons obtained is noticeably lower than that of the other specias of shrews, but higher than same species in other parts of its range.