Izvestiâ Akademii nauk. Rossijskaâ akademiâ nauk. Seriâ biologičeskaâ

The effect of a pulsed magnetic field (PMF) on meristem cells of onion seedlings was compared with the effects of acute gamma irradiation using the allium test. It was found that a pulse with a carrier frequency of 1.8 MHz, a pulse repetition rate of 28 kHz, and a magnetic field induction of 75 mT per pulse leads to an increase in the mitotic index, mainly due to an increase in the proportion of cells in the prophase, an increase in the frequency of cells with chromosome aberrations in the ana-telophase and does not affect the frequency of cells with micronuclei. It has been suggested that UTI causes nonspecific oxidative stress in plant cells, accompanied by a delay in the cell cycle at the check point (G2/M) and induction of DNA damage. According to these indicators, the PMF resembles the effect of ionizing radiation in doses of 0.05–0.5 Gy.

The influence of the lipid complex isolated from the thallus of the red marine algae Ahnfeltia tobuchiensis (LCA) on the metabolic parameters of the blood and liver of rats under a high-fat diet was studied. It was shown that the administration of LCA had a pronounced lipid-correcting and antioxidant effect, which was superior to that of the reference preparation “Omega 3-6-9” in terms of its ability to restore lipid metabolism, the ratio of lipoprotein fractions and the indices of the endogenous antioxidant protection system, as so as prevent the development of hepatosis. The lipid-correcting and anti-oxidant effect of LCA is specified by the action of n-3 polyunsaturated fatty acids, in particular eicosapentaenoic acid, which are the part of the structure of phospholipids and glycolipids of marine origin, which make up the main part of the studied lipid complex.

The number, species composition and taxonomic structure of fungal biota in the groundwater of natural springs and wells in the Moscow region were determined by сultural method. The number of fungi was low, on average from 10 to 300 colony-forming units (CFU) in 1 liter of water. 6–16 species were isolated from the water of one source or well, and totally 46 species were isolated from 6 studied objects. These were representatives of phylum Mucoromycota class Mucoromycetes (Absidia cylindrospora var. nigra, Mucor circinelloides, M. hiemalis, Rhizopus stolonifer), phylum Ascomycota class Eurotiomycetes (15 species of the genera Aspergillus and Penicillium), Sordariomycetes (13 species of the genera Acremonium, Chaetomium, Fusarium, Myrothecium, Plectosphaerella, Trichoderma), Dothideomycetes (Alternaria alternata, A. nobilis, Amorocoelophoma cassia, Cladosporium cladosporioides, C. sphaerospermum) and – Saccharomycetes (Candida solani, C. zeylanoides, Galactomyces pseudocandidus) and phylum Basidiomycota class Tremellomycetes (Mrakia gelida, Vishniacozyma victoriae) and Agaricomycetes (Phlebia acerina, Psathyrella candolleana, Thanatephorus cucumeris). The established taxonomic structure of fungal biota in the waters of natural springs and wells of the Moscow metropolis is similar to that found in the groundwater of other regions, including of groundwater at the depths of several hundred meters. The possibilities of adaptation of micromycetes to existence in ground water, the sources of its contamination and the need for mycological criteria for assessing water quality are discussed.

The analysis of the parasitic and endosymbiontofauna of the common newt (Lissotriton vulgaris L., 1758) in the natural and urban landscapes of the Middle Urals is presented for the first time. Four species of helminthes belonging to the Nematoda type were found, including 1 taxon indeterminate to the species (Nematoda sp.), and 1 species of endosymbionts (Chromista type). The works devoted to the species composition of L. vulgaris parasites on the territory of Eurasia are analyzed. The fauna of the helminthes of the common newt on the eastern slope of the Urals is depleted, which is probably determined by the limited distribution of the species outside Europe, the temperature regime in the north and moisture availability in the south.

Extra-pair paternity is widespread in passerine birds. The number of extra-pair young (EPY) varies among different species and populations of the same species. We tested if it is a case for a small passerine bird with poly-territorial behaviour, the Wood Warbler (Phylloscopus sibilatrix). The results are based on the microsatellite analysis of seven loci and revealed a high level of EPY in Central Russia population of Wood Warbler (EPY in 41% of all nests, 16 of 39 nests; 25% of all young were EPY, 52 of 212 young). We did not find relationship between relatedness among mates in the pair and the presence of EPY. There was no difference in heterozygosity and body mass between EPY and within pair young (WPY). Possible causes of extra-pair paternity are discussed.

The abundance, biomass, distribution and feeding patterns of the ctenophore Mnemiopsis leidyi A. Agassiz 1865 were studied in the deep-water Black Sea in October 2019. The biomass of the ctenophore in the open areas of the sea was 100–200 g m^–2, the abundance was 16–38 ind. m^–2. With the dominance of large individuals (≥30 mm) in the population, the activity of their reproduction remained extremely weak. The specific daily ration varied from ~4% to 13% of body carbon in adults and juveniles, respectively, and exceeded the minimum food requirements of the ctenophore. The daily consumption of three species of copepods (Acartia spp., Calanus euxinus, Oithona davisae) by M. leidyi reached 4.5–11% of their biomass, while that of appendicularians Oikopleura (Vexillaria) dioica – < 1.6%. The predatory pressure of M. leidyi on the entire prey zooplankton attained 2–4% of the biomass of organisms per day.

Denitrification losses of nitrogen-containing gases in the biome of boreal forests are discussed. In the soils of coniferous and deciduous forests of Western Europe, 0.57 ± 0.2 and 1.0 ± 0.2 kg N-N₂O/ha/ year are lost during denitrification. In North America this figure was 0.35 ± 0.29 kg N-N₂O/ha/yr for all stands. The emission of N₂O from forest soils correlated with the input of nitrogen from the atmosphere with r = 0.47 in coniferous forests and with r = 0.68 in deciduous plantations, returning to the atmosphere up to 30% of the nitrogen supplied with atmospheric precipitation. With a high input of nitrogen from the atmosphere, the emission of nitrogen-containing gases reached 20 kg N /ha /yr. Of these, NO, N₂O, and N₂ accounted for 21, 15, and 64%. Measurements of NO and especially N₂ emissions remain very rare, leading to incomplete estimates of denitrification losses. Denitrification remains the most complex process in the nitrogen cycle, with no definitive methods for measuring it.

This paper presents for the first time the results of studying the total content of antioxidants in the seeds of Morus L. The composition of fatty and steric acids of the seeds of mulberry fruits Morus L. was also studied: polymorphic species Morus alba (white-fruited, pink-fruited, black-fruited) and Morus nigra (Khartut variety). As a result of the studies, 12 fatty acids were identified. The main ones were linoleic acid, palmitic oleic acid, and stearic acid. The predominant fatty acid in all samples was linoleic, which varied from 67.5 to 79.0%. 15 sterols were found, among which β-Sitosterol accounts for about 90%. Determination of the total antioxidant content of Morus alba seeds (white-fruited, pink-fruited, black-fruited forms) and Morus nigra (Khartut variety) revealed the accumulation of antioxidants in all samples. The highest total content of antioxidants was observed in Morus nigra (4.40 mg/g) and the white-fruited form of Morus alba (5.56 mg/g).

A comparative study of some parameters of erythrocytes of bearded seals of different ages (3 years, 5 years, 10 years) was carried out. It has been established that with age, the resistance of erythrocyte membranes to hemolysis increases. During puberty, the intensity of glycolysis in the bearded seals erythrocytes increases and then decreases in adult animals. Differences in the content of potassium, calcium, magnesium in the erythrocytes of animals of the studied age groups are shown.