Doklady Biological Sciences最新文献

The contents of main classes of storage lipids (triacylglycerols, cholesterol esters, and waxes) in muscles and the liver of the beaked redfish Sebastes mentella were studied across the depth gradient and in different areas of the North Atlantic. Significant differences in storage lipid contents were observed between fish from different fishing horizons. The depth-dependent changes in lipids in fish tissues and organs were assumed to indicate that triacylglycerols (TAGs), cholesterol esters (CEs), and waxes are utilized as energy sources, in particular, to maintain the buoyancy during vertical migration. The results provide a basis for further investigation of the biochemical mechanisms of migration in the commercially valuable species S. mentella of the North Atlantic and other aquatic organisms with similar swimming activities.

Activities of energy and carbohydrate metabolism enzymes (cytochrome c oxidase (COX), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PD), glycerol 1-phosphate dehydrogenase (G1PDH), lactate dehydrogenase (LDH), and aldolase) were studied in rainbow trout Oncorhynchus mykiss Walb. fish grown in aquaculture in North Ossetia-Alania after introducing a regime with 24-h lighting and night feeding. COX and PK activities in the liver of fish from the experimental group were found to be significantly higher than in control fish, indicating an increase in aerobic ATP synthesis. Aldolase activity in organs of fish grown with 24-h lighting was lower than in the control fish, indicating a decrease in carbohydrate utilization in glycolysis in muscles and a lower intensity of gluconeogenesis in the liver. The differences made it possible to assume that the introduction of 24-h lighting and night feeding changed energy and carbohydrate metabolism to facilitate biosynthetic processes and, therefore, weight gain in fish.

The incomplete skull of Hapalodectes (Hapalodectidae, Mesonychia) is described from the Upper Paleocene Naran Member of the Naran Bulak Formation of the Khaychin-Ula 2 locality in the Bugin Tsav Basin in the south of Mongolia. This is the first discovery of the skull of a Paleocene member of the genus. The skull corresponds in size and dental occlusion to the species H. dux Lopatin, 2001, previously known only from a lower jaw from the Upper Paleocene Zhigden Member of the Naran Bulak Formation of the Tsagan-Khushu locality in the Nemegt Basin. In the structure of the facial part of the skull, H. dux exhibits features shared with Mesonychidae, namely the significant participation of the lacrimal and jugal in the preorbital region. The upper molars of H. dux were found to have distinct conules (a first for Hapalodectidae). The evolutionary changes in the structure of the upper molars of Hapalodectes (disappearance of the conules, decrease of the metacone, and narrowing of the lingual lobe) are determined. They were correlated with the transformations of the lower molars (reduction of the metaconid, protocristid, and entoconid, transverse compression of the trigonid and talonid) and together with them were aimed at enhancing the shearing action of the longitudinal trenchant blades of the posterior part of the dentitions.

The total lipid (TL) and fatty acid (FA) contents in tissues and body segments were studied in adult Antarctic krill (Euphausia superba) caught in three regions of the Atlantic sector of Antarctica with different environmental conditions. Significant differences in lipid and FA status of the Antarctic krill tissues and body segments were observed in the regions. Main metabolic indices indicating quality of lipids showed that E. superba has a high nutritional value. In particular, lipids are highly unsaturated in the species and ratios of physiologically significant and essential FAs are favorable to human health. This was assumed to be a distinctive biochemical characteristic of the species. Data from the study can be used to form a scientifically based approach to further technological processing of raw krill and targeted extraction of certain substances and components of a lipid nature.

Abstract-Myxomycetes are amoeboid fungus-like organisms (Amoebozoa) with a unique life cycle characterized by a great morphological diversity of fruiting bodies. Due to the similarity of these structures to the fruiting bodies of some representatives of Ascomycota and Basidiomycota, myxomycetes have been classified as fungi since the first known scientific description in 1654. Only in the 19th century, when their life cycle was studied, did the difference of this group from fungi become clear. During the same period, microscopic structures of fruiting bodies, as well as ornamentation of the spore surface, began to be considered as diagnostic features. Due to this, in the period from the end of the 19th to the middle of the 20th century, a rather stable system was formed. However, as further studies have shown, both macro- and micromorphological characters are often quite variable, depend on environmental conditions, and often result from convergent evolution, which causes difficulties in defining species and taxonomic units of higher ranks. Since the first decade of the 21st century, due to the development of molecular genetic methods and the accumulation of data on nucleotide sequences of marker genes together with the improvement of microscopic studies, it has been possible to obtain data on the evolutionary relationships of different groups of myxomycetes. A milestone in this process was the publication of the first phylogenetic system of myxomycetes in 2019. This work was the starting point for a number of studies on the relationships between different groups of myxomycetes at a lower taxonomic level. Thus, there has been a surge in the number of studies that bring us closer to constructing a natural system.

Activities of key enzymes of energy and carbohydrate metabolism (cytochrome c oxidase (COX), lactate dehydrogenase (LDH), aldolase, glucose 6-phosphate dehydrogenase (G6PDH), and 1-glycerophosphate dehydrogenase (1-GPDH)) were studied in pink salmon Oncorhynchus gorbuscha (Walb.) smolts from the White Sea in a cage experiment simulating the transition from a freshwater to a marine environment. A decrease in COX, G6PDH, and 1-GPDH activities and an increase in LDH and aldolase activities were observed in juveniles with an increase in water salinity. Based on the findings, a redistribution of energy substrates between the reactions of aerobic and anaerobic metabolism towards higher anaerobic ATP synthesis was assumed for pink salmon. This may indicate that adaptive mechanisms rearrange metabolism to provide energy for osmoregulation in pink salmon juveniles when the salinity changes in their habitat.

Abstract-Numerous studies of microorganisms isolated from the surface of cultural heritage objects, including library documents, are regularly carried out in different countries. Although the micromycete composition in each case varies, some species are constantly isolated. The structure of micromycete communities that inhabit library documents was studied in 57 cities of Russia located in seven federal districts (Northwestern, Central, Southern, Volga, Ural, Siberian, and Far Eastern). Micromycetes of 95 species from 32 genera were isolated and identified. The mycobiota of the library documents represented by Ascomycota has more than 90% of the species richness; Mucoromycota make up 3-9% and Basidiomycota, 3-4%. The Aspergillaceae family was the leading family: it accounted for 48.5-67.3% of the total species richness. In all regions, species diversity is moderate: the Shannon index ranged from 2.7 to 3.3. The Mcintosh species richness index is high everywhere (48-126), except in the Ural district (15.3). The McIntosh (0.76-0.84) and Pielow (0.80-0.91) dominance indices indicate a high level of species evenness in the mycobiota. The obtained values demonstrate the stability the document mycobiota in libraries from different regions. Significant species similarity between the districts was revealed by calculation of binary coefficients: the Jaccard coefficient was from 0.44 to 0.60; the Sørensen's qualitative measure of similarity was from 0.63 to 0.75; the quantitative similarity measure of Sørensen was from 0.44 to 0.71, and Morisita-Horn was from 0.66 to 1.0. The groups of dominant species in different regions are quite similar. The study of the ecological diversity of mycobiota on library books demonstrated the moderate diversity and the stability of the community. A high degree of similarity of taxonomic structures was established regardless of the climate conditions of the regions. Cosmopolitans characterized by high frequency of occurrence formed the major core of the library book mycobiota: Alternaria alternata, Aspergillus niger, Cladosporium cladosporioides, Mucor plumbeus, and Penicillium aurantiogriseum.

Abstract-In the Plyussky district of the Pskov region, an experiment was carried out to infect birch trees with the Chaga pathogen Inonotus obliquus in an 18-year-old postagrogenic birch forest. After 10 years of the experiment, sterile bodies of Chaga were found on six out of ten trees, swelling of the bark was found in one tree, and one tree died from Phellinus nigricans. Infected trees continued to grow at a rate no different from the rest of the forest. Sterile growths were mainly located above the inoculation site. The study showed that the production of Chaga raw materials can be considered as an additional form of forest management in the Non-Black Earth Region of Russia.

The wild nature monument "184-year-old oak tree in the village of Irinovka" (Leningrad oblast, Russia), better known in local historical literature as "Irinovsky Oak," was officially opened in 2013. It is represented by a separate pedunculate oak tree (Quercus robur), planted in 1829 and preserved in satisfactory condition at 194 years of age. This paper presents data from a survey of the shoot system of the tree investigated. A total of 12 fungal species were registered (Cladosporium herbarum, Colpoma quercinum, Coryneum depressum, Diatrypella quercina, Erysiphe alphitoides, Hyphoderma setigerum, Laetiporus sulphureus, Mar-chandiomyces corallinus, Peniophora quercina, Trichoderma viride, Sphaerulina quercicola, Vuilleminia comedens). The lichenicolous species Marchandiomyces corallinus was reported as a new find to the Leningrad oblast. It was shown that the shoot system of the tree investigated is associated with a complex of Quercus robur-adapted and coadapted species, among which such necrotrophs as Sphaerulina quercicola and Coryneum depressum and such pathogenic saprotrophs as Vuilleminia comedens and Colpoma quercinum, as well as saprotrophs (Diatrypella quercina, Peniophora quercina), dominated. This species complex ensures a continuous process of the crown's thinning.

Electroconvulsive therapy (ECT) is an effective treatment method for depression therapy. It produces a number of biological effects, including neurotrophic factors regulation. In the present paper, we investigated the ECT response in depressed rats subjected to the variable frequency ultrasound (20-45 kHz) and examined the contribution of brain-derived neurotrophic factor (BDNF) expression changes to the observed effects. The obtained results reflect the therapeutic potential of ECT for the treatment of depressive-like state in rodents and indicate the role of BDNF in these processes. In future research, it is necessary to investigate the relationship between neurotrophin and structural changes and to study other neurotrophic biomarkers that may be associated with the development of depression-like state and the therapy response.