No 5 (2024)
DEVELOPMENTAL BIOLOGY
The content of endogenous hormones in explants and calluses of Lavandula angustifolia Mill. at the initial stages of in vitro culture
Abstract
The content of endogenous hormones (auxin IAA, cytokinines, ABA) in explants of various types (segments of leaf, bud, stem), primary calluses induced from them, as well as morphogenic and non-morphogenic 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 hormone levels in such explants as segments of 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 morphogenic callus compared with non-morphogenic callus. It is suggested that the content of endogenous hormones in explants and calluses of L. angustifolia is due to their histological status. The conclusion is made about the unified histophysiological mechanisms of callusogenesis and morphogenesis in vitro in the studied plant.
551–561
ГЕНЕТИКА
Non-coding RNAs involved in the regulation of signaling pathways as possible markers of non-alcoholic fatty liver disease progression
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), the expression of which may be 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.
562–584
МИКРОБИОЛОГИЯ
Heavy metals-resistant PGPR strains of Pseudomonas sp. stimulating the growth of alfalfa under cadmium stress
Abstract
Three bacteria strains of Pseudomonas sp. resistant to heavy metals were isolated from the chemically contaminated soil. According to the results on the nucleotide sequences of the 16S rRNA and rpoD genes, strain Pseudomonas sp. 17 НМ was identified as Pseudomonas capeferrum, and the strains of Pseudomonas sp. 65 НМ и 67 НМ were most closely related to the type strain of Pseudomonas silesiensis и Pseudomonas umsongensis, respectively. It has been shown that strains of Pseudomonas sp. 17 НМ, 65 НМ, 67 НМ are characterized by different levels of resistance of heavy metals: maximum tolerance concentration (MTC) of zinc was 1 mМ for all strains, cadmium 1, 1.5, 1 mМ, lead 5, 5, 4 mМ, nickel 7, 9, 7 mМ, respectively. All pseudomonad strains can form biofilms and have the properties of PGPR bacteria. Treatment of alfalfa seeds (Medicago sativa L.) with strains Pseudomonas sp. 17 НМ, 65 НМ, 67 НМ under cadmium stress led to an increase in the dry weight of alfalfa seedling up to 40 % and the content of chlorophyll a and b in the leaves by 25-33% relative to the control.
585–595
PLANT PHYSIOLOGY
Molecular aspects of regulation of expression of homeologic glutamate dehydrogenase genes in wheat leaves under hypoxia
Abstract
An increase in GDH activity has been established when plants are exposed to hypoxic conditions in the first 6 hours, which ensures the formation of an adaptive response of cellular metabolism to the lack of oxygen in the cell. A difference in the transcriptional activity of homeologous GDH-1 genes in wheat leaves under stress conditions was shown. An increase in the mRNA content of the GDH-1(5A) gene in wheat leaves when plants are exposed to hypoxic conditions is observed in the first hours of the experiment, which correlates with a change in the catalytic activity of glutamate dehydrogenase. Regulation of this gene is carried out by the transcription factor HIF, the specific landing site of which is found in the transcription initiation site of the promoter of this gene.
596–604
ZOOLOGY
First knowledge on the ultrathin structure of the tegument “Cystacanth” of the acanthocephala Neoechinorhynchus beringianus Mikhailova, Atrashkevich, 2008 (Eoacanthocephala, Neoechinorynchidae)
Abstract
For the first time, the ultrastructure of the metasoma tegument of the developing acanthocephalan Neoechinorhynchus beringianus (Neoechinorhynchidae) was studied at representatives of the Eoacanthocephala class. Completely developed acanthellae of this species were shown to have no cyst, which is a characteristic feature of cystacanths of similar development stages in representatives of other acanthocephalan classes; and the protection function from the host response is performed by a thick layer of glycocalyx on the tegument surface. The tegument is represented by a typical symplast, including a standard set of layers (cross-striated, felt-fibrous, radially 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 allow using the term “cystacanth” concerning them.
605–609
Leukocyte composition of immune organs of Coregonus migratorius, infected Dibothriocephalus dendriticus
Abstract
For the first time, an analysis of leukocyte changes in the immune organs (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 hardly involved in antiparasitic defense.
610–620
Automated identification and counting of saigas (Saiga tatarica) by using deep convolutional neural networks in high-resolution satellite images
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 1,284 saigas on the entire model satellite image, while a zoological expert manually identified 1,412 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”.
621–637
The presence and microstructure of down compartments of feathers in representatives of nineteen orders of birds (Aves)
Abstract
An inventory and description of the occurrence of the first studied down structures of feathers: combined barbs with typical down barbules and combined barbs with modified down barbules are carried out. The occurrence and distribution of these structures, as well as additional feather and umbilical barbs in different plumage pterylia of 441 birds of 129 species belonging to 19 orders were noted; 3330 feathers have been studied. Downy structures in the orders Charadriiformes and Passeriformes have been studied in most details. In the order Charadriiformes the families and their constituent species differ in the presence or absence of modified barbules. In the feathers of representatives of the order Passeriformes an additional feather/umbilical barbs and modified barbules do not occur in one of the same feathers. In the plumage of representatives of all studied taxa combined barbs with typical down barbules were found, which are present to a greater extent in the cover feathers, and to a lesser extent, on the flight and tail feathers. Combined barbs with modified down barbules are not so widespread in the plumage of the studied taxa and they are present only on the cover feathers. Among the studied orders the additional feather and umbilical barbs are absent in the plumage of Coraciiformes and Upupiformes. The adaptive and diagnostic significance of the studied downy structures is noted. The main function of all downy structures is thermal insulation, while maintaining the rigidity of plumage, preventing its sticking and sealing can be called secondary. The presence in some groups of birds on one and the same feather of an additional feather/umbilical barbs and modified barbules, as well as their various combinations, can be used as a taxonomic sign in combination with other ptylological characters. The presence of downy formations, their shape, structure, size and other features may indicate pterylia within some taxonomic groups of feathers. Along with visual inspection of feathers, light and electron microscopy was also used.
638–645
ФИЗИОЛОГИЯ ЖИВОТНЫХ И ЧЕЛОВЕКА
Dynamics of food passing through the digestive tract in the nocturnal rodent Meriones crassus as a response to the rhythm of feeding activity
Abstract
The dependence of the food passing through the digestive tract (DT) on the feeding activity in the nocturnal rodent Meriones crassus was studied. Two groups of gerbils were housed in laboratory under artificial lighting at a photoperiod of 12:12 L:D for 36 hours. Groups were named “day” (L:D=20:16) and “night” (L:D=12:24) according to predominance light or dark time during the experiment. The average retention time of markers in the stomach in these groups was 20 and 30 hours, 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 2 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 caecum stays here for a longer time. In the “day” group, by the end of the experiment, 84% of the markers were removed from DT, and in the “night” group, about 55%.
646–653
ECOLOGY
Preferences of the Myxosporeans of genus Kudoa Meglitch, 1947 of the world’s fauna fishes living at certain depths
Abstract
This paper provides the first information on the possible occurrence of myxosporeans of the genus Kudoa in fish of the World Ocean and, in several individual cases, in associated freshwater bodies at different depths. For the first time, an analysis of the theoretically assumed association of Kudoa to different depths of habitat of their fish hosts of the World fauna is given. It was revealed that in the shelf zones adjacent to the shores, all species of myxosporeans of the genus Kudoa can be found, of which 90 species (70.8% of the total) are found exclusively in the shelf zone, and the hosts of 50 species of Kudoa (39.4%) live in its shallowest part (up to 50 m). At depths from the shelf to 500 and 1000 meters, 16 species (12.6%) and 14 species (11%) of this genus can be found, respectively. At depths of up to 1500 and 3000 m, theoretically, from 1 to 3 species of Kudoa can be found, which is from 0.8 to 2.4% of all known representatives of these parasites.
654–672
КРАТКИЕ СООБЩЕНИЯ
Impact of biotic and abiotic factors on epibiotic communities of the Barents Sea red king crab
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 diminished role in the formation of fouling communities. Temperature conditions during the mass molting periods were found to have significant effects, apparently serving as a catalyst for the primary settlement of crab shells by benthic organisms. Our data not only yield 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.
673–678