Biology Bulletin最新文献

Abstract

The current understanding of the role of non-coding RNAs in the regulation of signaling pathways that control lipid accumulation and the development of inflammation in non-alcoholic fatty liver disease (NAFLD) is outlined. The contribution of peroxisome proliferator-activated receptors (PPARs) to changes in lipid metabolism and the formation of lipotoxicity as trigger mechanisms of NAFLD is considered. The role of TGFβ, TNFα/NF-κb, IL-6/JAK/STAT3 signaling pathways in the activation of stellate cells, liver fibrogenesis and the progression of NAFLD has been demonstrated. Analysis of literature data has revealed a number of microRNAs and long non-coding RNAs (lncRNAs) presumably associated with the regulation of these signaling pathways in this disease. They may probably have prognostic significance for differentiating clinical forms and severity of NAFLD.

Abstract

Based on a long-term dataset of species composition and infestation levels of associated organisms on the invasive Barents Sea red king crab, a multivariate analysis was conducted to determine the contributions of biotic and abiotic factors to the fouling community structure. Results indicate that host size and exoskeleton age were the most significant factors for diversity indices and infestation intensity. Abiotic factors played a lesser role in the formation of fouling communities. Temperature conditions during the mass molting periods were found to have significant effects, apparently acting as a trigger for the primary settlement of crab shells by benthic organisms. Our data not only provide new insights into the formation of fouling communities of decapod crustaceans, but also provide valuable information for further studies on the adaptation process of the red crab to the conditions of the Barents Sea.

This paper provides first information about possible occurrence of the myxosporean genus Kudoa in fish of the World Ocean and, in some cases, in associated freshwater bodies at different depths. An analysis of the theoretically assumed site preference by Kudoa of different habitat depths of their fish hosts in the World Fauna is made for the first time. It is revealed that all species of the myxosporean genus Kudoa can be found in coastal shelf zones, of which 90 species (70.8% of the total) occur exclusively in the shelf zone, and the hosts of 50 Kudoa species (39.4%) live in its shallowest part (down to 50 m). 16 species (12.6%) and 14 species (11%) of this genus can be found at depths from the shelf to 500 meters and 1000 meters, respectively. From 1 to 3 species of Kudoa can be encountered theoretically at 1500 m to 3000 m, which is from 0.8 to 2.4% of all known representatives of these parasites.

Abstract

The ultrastructure of the metasoma tegument of the developing acanthocephalan Neoechinorhynchus beringianus (Neoechinorhynchidae) was studied for the first time for representatives of the class Eoacanthocephala. The completely developed acanthellae of this species were shown to have no cyst, which is a characteristic feature of cystacanths at these stages of development in other acanthocephalan classes, and protection against the host response is provided by a thick layer of glycocalyx on the tegument surface. The tegument is represented by a typical symplast and includes a standard set of layers (cross-striated, felt-fibrous, radial-fibrous, and tubular), and is underlain by a basal plate and two layers of muscles. The absence of a cyst in the completely developed acanthellae under study does not permit us to use the term “cystacanth” concerning them.

Abstract

We used light and raster electron microscopy to study for the first time in research the microstructure of the down parts of feather vanes consisting of combined barbules (“barbule I”) provided with both typical plumulaceous barbules (“barbicel,” “barbule II”) and modified plumulaceous barbules (MBs). Their presence and distribution over different pterylae were studied on 3330 feathers from 441 birds of 129 species belonging to 45 families of 19 orders. Information about the presence of afterfeathers and of umbilical barbs on feathers was clarified. Modified plumulaceous barbules were found on feathers of all species studied, more often on coverts, less often on wing and tail feathers. Down components were studied in most detail in the orders Charadriiformes and Passeriformes; in the former, the presence or absence of MB was specific at the level of family or genus, while in the latter, afterfeathers or umbilical barbs were never found together on the same feather. The possibility is discussed of using various combinations of down components and features of their microstructure as an important addition to the integrated system of ptilological taxa identification by feathers (including single feathers) and in some cases even by the pteryla to which the tested feather belongs.

Abstract

We utilized a two-phase analysis using deep convolutional neural networks (DCNN) to create an automated technology that enabled us to detect and count saigas (Saiga tatarica) in satellite images with a resolution of 0.3–0.5 m/pixel (Eros-B 2012; 2013 and Beijing KA 2022 satellites). In the first phase, the satellite image is automatically divided into sections and checked for the presence or absence of clusters of objects (the “classification” phase). Then, during the second phase, only the fragments of the satellite image where at least one saiga was previously found are analyzed (the “detection” phase). The method was calibrated by training a neural network on the results of the preliminary processing of archival satellite images from 2012 and 2013, carried out manually by zoological experts. When we tested the DCNN work with a “confidence threshold” of 0.3, we identified 1284 saigas on the entire model satellite image, while a zoological expert manually identified 1412 saigas. For practical use and to assess the effectiveness of this method, we counted saigas on a 2022 image covering two adjacent specially protected natural areas (PAs) located in the Republic of Kalmykia and the Astrakhan region (Russian Federation). The results are presented with different “thresholds of confidence.”

Abstract

For the first time, an analysis of leukocyte changes in the organs of the immune system (pronephros, mesonephros, and spleen) of the Baikal omul Coregonus migratorius (Georgi, 1775) (Salmoniformes: Coregonidae) infected with Dibothriocephalus dendriticus (Nitsch, 1824) (syn. Diphyllobothrium dendriticum) (Cestoda: Diphyllobothriidea) is presented in natural habitat conditions. In the pronephros of infected fish, the number of poorly differentiated neutrophils (myelocytes and metamyelocytes) was significantly higher than in uninfected fish, which indicated inflammatory processes. D. dendriticus triggered the immunoregulatory processes in the body of infected fish, as evidenced by the decrease in the total number of lymphocytes and prolymphocytes (B-lymphocytes) in the pronephros and the increase in prolymphocytes in the spleen. The other effector elements (cells of the monocyte–macrophage lineage, basophils, and eosinophils) were barely involved in antiparasitic defense.

Abstract

Three bacteria strains of Pseudomonas sp. resistant to heavy metals were isolated from chemically contaminated soil. An analysis of the nucleotide sequences of the 16S rRNA and rpoD genes identified the Pseudomonas sp. 17 НМ strain as Pseudomonas capeferrum, and the strains of Pseudomonas sp. 65 НМ and 67 НМ were most closely related to the type strains of Pseudomonas silesiensis and Pseudomonas umsongensis, respectively. It was shown that the strains of Pseudomonas sp. 17 НМ, 65 НМ, and 67 НМ were characterized by different levels of resistance to heavy metals, with the maximum tolerable concentration (MTC) of zinc being 1 mМ for all strains, that of cadmium, 1, 1.5, and 1 mМ; of lead, 5, 5, and 4 mМ; and of nickel, 7, 9, and 7 mМ, respectively. All Pseudomonas strains can form biofilms and have the properties of PGPR bacteria. Treatment of alfalfa seeds (Medicago sativa L.) with the strains of Pseudomonas sp. 17 НМ, 65 НМ, and 67 НМ under cadmium stress increased the dry weight of alfalfa seedlings up to 40% and the content of chlorophyll a and b in the leaves by 25–33% relative to the control.

Abstract

The dependence of the food passing through the digestive tract (DT) on feeding activity in the nocturnal rodent Meriones crassus was studied. Two groups of gerbils were housed in the laboratory under artificial lighting at a photoperiod of 12 : 12 L : D for 36 h. The groups were named “day” (L : D = 20 : 16) and “night” (L : D = 12 : 24) according to the predominance light or dark time during the experiment. The mean retention time of markers in the stomach in these groups was 20 and 30 h, respectively. The kinetics of the contents changed depending on the specific time of consumption of the markers and the saturation level of the rodents with food. During the daylight hours, sequential evacuation of markers entering the DT begins from the stomach after two hours, and at night, during a period of higher feeding activity, part of the food located in the fornix of the stomach and in the cecum stays here for a longer time. In the “day” group, by the end of the experiment, 84% of the markers were removed from the DT, and in the “night” group, about 55%.

Abstract

The content of endogenous hormones (auxin IAA, cytokinines, ABA) in explants of various types (segments of the leaf, bud, and stem), primary calluses induced from them, and morphogenic and nonmorphogenic calluses at the initial stages of in vitro culture by the immunoassay method was studied for the first time for Lavandula angustifolia Mill. The maximum value of the hormone levels in explants such as segments of a bud was shown. An increase in the content of hormones in primary calluses was revealed in comparison with similar characteristics in all types of explants. The higher level of the active form of cytokinin (trans-zeatin) and ABA, as well as the lower level of the inactive form of cytokinin (zeatin-nucleotide) and auxin IAA, were identified in the morphogenic callus compared with the nonmorphogenic one. It is suggested that the content of endogenous hormones in explants and calluses of L. angustifolia is due to their histological status. A conclusion is made about the unified histophysiological mechanisms of callusogenesis and morphogenesis in vitro in the studied plant.