bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuroinflammation in the pathogenesis of the audiogenic epilepsy: altered proinflammatory cytokine levels in Krushinsky-Molodkina seizure-prone rats
Authors: Surina N. M , Fedotova I. B , Nikolaev G. M , Grechenko V. V , Gankovskaya L. V , Ogurtsova A. D , Poletaeva I. I
Published: April 2024

Neuroinflammation plays an important role in epileptogenesis, however, most studies are performed on pharmacological models of epilepsy, while data on non-invasive, including genetic, models are practically absent. In Krushinsky-Molodkina (KM) strain rats with high genetically caused predisposition to AE (intensive audiogenic seizure fit in response to the action of sound) and in the control strain “0” (not predisposed to AE), the levels of a number of pro-inflammatory cytokines were investigated using multiplex immunofluorescence magnetic assay (MILLIPLEX map Kit). Cytokine levels were determined in the dorsal striatum tissue and in the brain stem. Background levels of IL-1β, IL-6 and TNF-α in the dorsal striatum of KM rats were significantly lower than in rats “0” (32.31, 27.84 and 38.87% of decrease, respectively, p < 0.05, 0.05 and 0.01), whereas in the brain stem in the “background” state of interstrain differences in levels of these metabolites were not detected. 4 h after sound exposure, the TNF-α level in the dorsal striatum of KM rats was significantly (38.34%, p < 0.01) lower than in “0” rats. In KM rats, after the action of sound and the subsequent seizure fit, the levels of IL-1β and IL-6 in the dorsal striatum were significantly higher compared to the background (35.29 and 50.21%, of increase, p < 0.05, 0.01, respectively). The IL-2 level in KM rats in the background state was not detected, whereas after audiogenic seizures its level was 14.01 pg/ml (significantly higher, p < 0.01). In the brain stem of KM rats, the levels of IL-1β and TNF-α after audiogenic seizures were significantly lower than in the background (13.23 and 23.44% of decrease, respectively, p < 0.05). In rats of the “0” strain, the levels of cytokines in the dorsal striatum after the action of sound (which did not cause AE seizures) did not differ from those in the background, while the levels of IL-1β in their brain stem were lower than in the background (40.28%, p < 0.01). Thus, the differences between the background levels of cytokines and those after the action of sound were different in rats that differed in their predisposition to AE, which suggests the involvement of these metabolites in the pathophysiology of epilepsy.
Molecular mechanisms of astrocyte involvement in synaptogenesis and brain synaptic plasticity
Authors: Khaspekov L. G , Frumkina L. E
Published: April 2024

Astrocytes perform a wide range of important functions in the brain. As structural and functional components of synapses, astrocytes secrete various factors (proteins, lipids, small molecules, etc.) that bind to neuronal receptor and contribute to synaptogenesis and regulation of synaptic contacts. Astrocytic factors play a key role in the formation of neural networks undergoing short- and long-term synaptic morphological and functional rearrangements essential in the memory formation and behavior. The review summarizes the data on the molecular mechanisms mediating the involvement of astrocyte-secreted factors in synaptogenesis in the brain and provides up-to-date information on the role of astrocytes and astrocytic synaptogenic factors in the long-term plastic rearrangements of synaptic contacts.
Myelin olygodendrocyte glycoprotein - autoantigen in inflammatory demyelinating diseases of the central nervous system
Authors: Eliseeva D. D , Zakharova M. N
Published: April 2024

Demyelinating diseases of the CNS are a result of an autoimmune attack to the myelin sheaths surrounding axons. Their structural proteins become antigenic and as a result, myelin lesions appear. The identification of specific antibodies directed against the components of myelin, using highly specialized methods of laboratory diagnostics, can significantly improve diagnostic approaches. Currently, myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) consists of demyelinating syndromes with an identified antigen. The pathogenic role of human MOG-IgG has been demonstrated, which makes it possible to isolate this disease into a separate nosological form. However, for the myelin oligodendrocyte glycoprotein (MOG) gene, alternative splicing can produce various isoforms, which hinders antigen detection even for the most advanced techniques of immunofluorescence analysis. On the other hand, MOG conformational changes provide the structural integrity of other myelin proteins and maintain immune autotolerance mechanisms that are unique to humans.
Natural guanine derivatives exert PARP-inhibitory and cytoprotective effects in a model of cardiomyocyte damage under oxidative stress
Authors: Shram S. I , Shcherbakova T. A , Abramova T. V , Baradieva E. C , Efremova A. S , Smirnovskaya M. S , Silnikov V. N , Švedas V. K , Nilov D. K
Published: April 2024

Inhibitors of human poly(ADP-ribose) polymerase (PARP) are considered as promising agents for the treatment of cardiovascular, neurological, and other diseases accompanied by inflammation and oxidative stress. Previously, the ability of the natural compounds 7-methylguanine (7mGua) and 8-hydroxy-7-methylguanine (8h7mGua) to suppress the activity of the recombinant PARP protein was demonstrated. In the present work, we have investigated the possibility of PARP-inhibitory and cytoprotective action of 7mGua and 8h7mGua against rat cardiomyoblast cultures (undifferentiated and differentiated H9c2). It was found that 7mGua and 8h7mGua rapidly penetrate into cells and effectively suppress H2O2-stimulated PARP activation (IC50 = 270 and 55 µM, respectively). The pronounced cytoprotective effects of 7mGua and 8h7mGua were shown in a cellular model of oxidative stress, and 8h7mGua exceeded the classic PARP inhibitor 3-aminobenzamide for effectiveness. The obtained data indicate the prospects for the development of PARP inhibitors based on guanine derivatives and their testing on models of ischemia-reperfusion tissue damage.
Structural and functional studies of tropomyosin isoforms Tpm4.1 and Tpm2.1
Authors: Logvinov A. S , Nefedova V. V , Yampolskaya D. S , Kleymenov S. Y , Levitsky D. I , Matyushenko A. M
Published: April 2024

Tropomyosin (Tpm) is one of the most important partners of the actin filament, largely determining its properties. In animal organisms, there are different isoforms of Tpm, which are believed to be involved in the regulation of various cellular functions. However, the molecular mechanisms of regulation of the functions of actin filaments by various cytoplasmic isoforms of Tpm are still poorly understood. In our work, we used various methods to study the properties of Tpm2.1 and Tpm4.1 isoforms and compared them both with each other and with the properties of Tpm isoforms that had already been subjected to more detailed study earlier. The isoforms Tpm2.1 and Tpm4.1 almost did not differ from each other in their affinity for F-actin, in the thermal stability of their molecules and in their resistance to limited proteolysis by trypsin, but they differed markedly in viscosity of their solutions and in the thermal stability of their complexes with F-actin. The main difference of Tpm2.1 and Tpm4.1 from other previously studied Tpm isoforms (such, for example, as Tpm1.6 and Tpm1.7) is their extremely low thermal stability measured by CD and DSC methods. The possible causes of this instability are considered in detail when comparing the amino acid sequences of Tpm4.1 and Tpm2.1 with the sequences of isoforms Tpm1.6 and Tpm1.7, which did not differ from Tpm4.1 and Tpm2.1, respectively, by the exon structure of their genes.
Phytohormones affect the differentiation of human dermal fibroblasts via UPR activation
Authors: Turishcheva E. P , Vildanova M. S , Vishnyakova P. A , Matveeva D. K , Saidova A. A , Onishchenko G. E , Smirnova E. A
Published: April 2024

Normalization of secretory activity and the level of differentiation of mesenchymal cells, including fibroblasts, is the important biomedical problem. One of the plausible solutions to this problem is to affect the unfolded protein response (UPR) signaling cascade, which is activated during fibroblast differentiation. In the present study, the effect of phytohormones on the secretory activity and differentiation of cultured human dermal fibroblasts was investigated. By analyzing the expression level of genes encoding UPR markers in these cells, we found that phytohormone abscisic acid (ABA) upregulated the expression of GRP78 and ATF4 genes, while phytohormone gibberellic acid (GA) upregulated the expression of CHOP. Evaluation of the biosynthetic activity of fibroblasts showed that ABA elevated the level of secretion and synthesis of procollagen I and the level of fibronectin synthesis, as well as total production of collagen and non-collagen proteins of extracellular matrix. ABA also stimulated the synthesis of smooth muscle actin α (α-SMA) and increased the number of myofibroblasts in cell population. On the contrary, GA increased the level of fibronectin secretion, but decreased the level of procollagen I synthesis, and reduced the total production of collagen proteins of extracellular matrix. Concomitantly, in these conditions we observed the decreased level of α-SMA synthesis and the number of myofibroblasts in the cell population. Our results suggest that phytohormones are the modulators of the biosynthetic activity of fibroblasts and affect their differentiation status.
Impact of cell-free dna from blood serum of mice with metastatic melanoma on the enhancement of oncogenic properties of melanoma cells
Authors: Filatova A. A , Alekseeva L. A , Savin I. A , Sen'kova A. V , Zenkova M. A , Mironova N. L
Published: April 2024

Currently, a significant increase in the levels of circulating cell-free DNA (cfDNA) in the blood of patients is a generally recognized marker of the development of oncological diseases. Although tumor-associated cfDNA has been well studied, its biological functions remain unclear. In this work, we investigated the effect of cfDNA isolated from the blood serum of mice with B16-F10 metastatic melanoma on the properties of B16-F10 melanoma cells in vitro. It was found that the profile of cfDNA isolated form blood serum of mice with melanoma differs significantly from the cfDNA isolated from blood serum of healthy mice, and is similar concerning the abundance of oncogenes and mobile genetic elements (MGE) to the genomic DNA of B16 cells. It was shown that cfDNA of mice with melanoma penetrated into B16 cells, resulting to the increase in the abundance of oncogenes and MGE fragments, and caused the 5-fold increased mRNA level of the secreted DNase Dnase1l3 and a slight increase of the mRNA level of the Jun, Fos, Ras, and Myc oncogenes. cfDNA of healthy mice caused increasing of mRNA level of the intracellular regulatory DNase EndoG and a 4-fold increase of mRNA level of Fos and Ras oncogenes, which are well-known triggers of a large number of signal cascades, from apoptosis inhibition to increased tumor cell proliferation. Thus, it is obvious that the circulating cfDNA of tumor origin is able to penetrate into cells and, despite the fact that no changes were found in the level of viability and migration activity of tumor cells, cfDNA, even with a single exposure, can cause changes at the cellular level that increase the oncogenicity of recipient cells.
Protein-protein interfaces as druggable targets: a common motif of the pyridoxal-5′-phosphate-dependent enzymes to receive the coenzyme from its producer
Authors: Aleshin V. A , Bunik V. I
Published: April 2024

Pyridoxal-5′-phosphate (PLP), a phosphorylated form of vitamin B6, acts as a coenzyme for numerous reactions, including those changed in cancer and/or associated with the disease prognosis. Since highly reactive PLP may modify cellular proteins, it is hypothesized to be directly transferred from its donors to acceptors. Our goal is to validate the hypothesis by finding common motif(s) in a multitude of the PLP-dependent enzymes for binding the limited number of the PLP donors, namely pyridoxal kinase (PdxK), pyridox(am)in-5′-phosphate oxidase (PNPO) and the PLP-binding protein (PLPBP). Experimentally confirmed interactions between the PLP donors and acceptors reveal that PdxK and PNPO interact with the PLP acceptors of folds I and II, while PLPBP - with those of folds III and V. Aligning the sequences and 3D structures of the identified interactors of PdxK and PNPO, we have found a common motif in the PLP-dependent enzymes of folds I and II. The motif extends from the enzyme surface to the neighborhood of the PLP binding site, represented by an exposed alfa-helix, a partially buried beta-strand and residual loops. Pathogenicity of mutations in human PLP-dependent enzymes within or in the vicinity of the motif, but outside of the active sites, supports functional significance of the motif that may provide an interface for the direct transfer of PLP from the sites of its synthesis to those of the coenzyme binding. The enzyme-specific amino acid residues of the common motif may be used to develop selective inhibitors blocking PLP delivery to the PLP-dependent enzymes critical for proliferation of malignant cells.
Regulation of human dna primase-polymerase primpol
Authors: Boldinova E. O , Makarova A. V
Published: April 2024

Transmission of genetic information depends on successful completion of DNA replication. Genomic DNA is subjected to damage on a daily basis. DNA lesions create obstacles for DNA polymerases and can lead to replication blockage, DNA break formation, cell cycle disruption and apoptosis. Cells have adapted to DNA damage evolving mechanisms allowing to eliminate lesions prior to DNA replication (DNA repair) and mechanisms which help to bypass lesions during DNA synthesis (DNA damage tolerance). The second group of pathways includes the mechanism of DNA synthesis restart at the damaged sites by DNA primase-polymerase PrimPol. Human PrimPol was first described in 2013. The properties and functions of PrimPol have been extensively studied in recent years, but very little is known about the regulation of PrimPol and the association of the enzyme dysfunction with diseases. The present review is devoted to an analysis of the mechanisms of human PrimPol regulation in the context of DNA replication. The interaction of PrimPol with other proteins is discussed in detail and an attempt is made to compile a possible pathway for the regulation of human PrimPol activity. The paper also addresses the relationship of PrimPol dysfunction with human diseases.
Complexes and supramolecular associates of dodecyl-containing oligonucleotides with serum albumin
Authors: Pavlova A. S , Ilyushchenko V. V , Kupryushkin M. S , Zharkov T. D , Dyudeeva E. S , Bauer I. A , Chubarov A. S , Pyshnyi D. V , Pyshnaya I. A
Published: April 2024

Serum albumin is currently in the focus of biomedical research as a promising platform for the creation of multicomponent self-assembling systems due to the presence of several sites with a high binding affinity of various compounds in its molecule, including lipophilic oligonucleotide conjugates. In this work, we investigated the stoichiometry of the dodecyl-containing oligonucleotides binding to bovine and human serum albumins via electrophoretic mobility shift assay. The results testify to the formation of albumin-oligonucleotide complexes with a stoichiometry of about 1 : (1.25 ± 0.25) under physiological-like conditions. Using atomic force microscopy, it was found that interaction of human serum albumin with a duplex of complementary dodecyl-containing oligonucleotides resulted in associates of round shape with a diameter of 165.5 ± 94.3 nm and 28.9 ± 16.9 nm in height, and with polydeoxyadenylic acid and dodecyl-containing oligothymidylate also resulted in formation of supramolecular associates with a size of about 315.4 ± 70.9 and 188.3 ± 43.7 nm. The obtained data allow considering dodecyl-containing oligonucleotides and albumin as potential components for the development of methods to design self-assembled systems for solving problems of molecular biology, biomedicine, and the development of unique theranostics with targeted action.
Generation of a cell line selectively producing the functionally active OATP1B1 transporter
Authors: Kotliarova M. S , Shchulkin A. V , Erokhina P. D , Mylnikov P. Y , Yakusheva E. N , Nadolinskaia N. I , Zamakhaev M. V , Goncharenko A. V
Published: April 2024

The solute carrier organic anion transporter family member OATP1B1 is one of the most important transporter proteins which mediate the penetration of many endogenous substances and xenobiotics into hepatocytes. A model system providing the expression of the functional protein is needed to assess the interaction of OATP1B1 with various substances. Based on HEK293 cells, we obtained the HEK293-OATP1B1 cell line, permanently expressing the SLCO1B1 gene encoding the OATP1B1 transporter. Expression of the SLCO1B1 gene was confirmed by real-time PCR analysis and immunochemically. The functionality of the transporter was assessed by the transport of atorvastatin, which is a substrate of OATP1B1. Cells of the resulting cell line, which selectively express the functionally active recombinant OATP1B1 transporter, can be used to study its function and to test drugs for belonging to substrates, inducers, and inhibitors of OATP1B1 to assess the risks of drug-drug interactions.
Development of a heterologous expression system and optimization of the algorithm for cholera toxin β-subunit production in E. coli
Authors: Jamgochian H. H , Zamakhaev M. V , Sluchanko N. N , Goncharenko A. V , Shumkov M. S
Published: April 2024

Cholera is a deadly infection disease, which is usually associated with low hygiene levels and restricted access to high-quality drinking water. An effective way to prevent cholera is the use of vaccines. Among active vaccine components there is the CtxB protein (cholera toxin β-subunit). In the current work, we have developed a genetic system for the production of recombinant CtxB in E. coli cells and studied the conditions for the synthesis and purification of the target product at the laboratory culture level. It has been found that the optimal algorithm for isolation of the recombinant protein is to grow an E. coli culture in a synthetic M9 medium with glycerol, followed by CtxB purification out of the spent culture medium through Ni2+-ions affinity chromatography techniques. Forty-eight hours following CtxB expression induction, the concentration of the target product can be up to 50 mg/liter in the culture medium. The CtxB protein retains its pentameric structure while expressing and through purification. The latter makes it possible to consider the developed system as a promising tool for the industrial-level synthesis of recombinant CtxB for medical and research purposes.
CRISPR/Cas9-mediated genome editing of the Komagataella phaffii to obtain a phytase-producer markerless strain
Authors: Tkachenko A. A , Borshchevskaya L. N , Sineoky S. P , Gordeeva T. L
Published: April 2024

Using the CRISPR/Cas9 system, the recipient strains K. phaffii VKPM Y-5013 (His- phenotype) and K. phaffii VKPM Y-5014 (Leu- phenotype) were derived from the K. phaffii VKPM Y-4287 strain, which has a high expression potential. Based on developed recipients, markerless producers can be obtained. The gene inactivation efficiency with different variants of sgRNA ranged from 65 to 98% and from 15 to 72% for HIS4 and LEU2, respectively. The recipient strains retained the growth characteristics of the parent strain and have a high expression potential, as estimated by the production of heterologous phytase from Citrobacter gillenii. The average productivity of the transformants based on K. phaffii VKPM Y-5013 and K. phaffii VKPM Y-5014 strains was 2.1 and 2.0 times higher than the productivity of the transformants of the commercial K. phaffii GS115 strain. Sequential integration of genetic material into the genome of the K. phaffii VKPM Y-5013 strain was proposed. A highly effective multicopy markerless strain producing C. gillenii phytase was obtained.
Production and characterisation of photorin, a new protein protease inhibitor from the entomopathogenic bacteria photorhabdus laumondii
Authors: Berdyshev I. M , Svetlova A. O , Chukhontseva K. N , Karaseva M. A , Varizhuk A. M , Filatov V. V , Kleymenov S. Y , Kostrov S. V , Demidyuk I. V
Published: April 2024

Entomopathogenic bacteria of the genus Photorhabdus secrete protease S (PrtS), which is considered as a virulence factor. We found that in Photorhabdus genomes, immediately after the prtS genes, there are genes that encode small hypothetical proteins homologous to emfourin, a recently discovered protein inhibitor of metalloproteases. Emfourin-like inhibitor gene from Photorhabdus laumondii subsp. laumondii TT01 was cloned and expressed in Escherichia coli cells. The recombinant protein, named photorin (Phin), was purified by metal chelate affinity and gel permeation chromatography and characterized. It has been established that Phin is a monomer and inhibits the activity of protealysin and thermolysin, which, like PrtS, belong to the M4 peptidase family. The inhibition constants were 1.0 ± 0.3 and 10 ± 2 µM, respectively. It was also demonstrated that Phin is able to suppress the proteolytic activity of P. laumondii culture broth (half-maximal inhibition concentration 3.9 ± 0.3 nM). Polyclonal antibodies to Phin were obtained, and it was shown by immunoblotting that P. laumondii cells produce Phin. Thus, the prtS genes in entomopathogenic bacteria of the genus Photorhabdus are colocalized with the genes of emphorin-like inhibitors, which probably regulate the activity of the enzyme during infection. Strict regulation of the activity of proteolytic enzymes is essential for the functioning of all living systems. At the same time, the principles of regulation of protease activity by protein inhibitors remain poorly understood. Bacterial protease-inhibitor pairs, such as the PrtS and Phin pair, are a promising model for in vivo studies of these principles. Bacteria of the genus Photorhabdus have a complex life cycle with multiple hosts, being both nematode symbionts and powerful insect pathogens. This provides a unique opportunity to use the PrtS and Phin pair as a model for studying the principles of regulation of protease activity by proteinaceous inhibitors in the context of bacterial interactions with different types of hosts.
Generation of electric potential difference by chromatophores from photosynthetic bacteria in the presence of trehalose under continuous illumination
Authors: Vitukhnovskaya L. A , Zaspa A. A , Mamedov M. D
Published: April 2024

Measurement of the electrical potential difference (Δψ) in membrane vesicles (chromatophores) from the purple bacterium Rhodobacter sphaeroides, associated with the surface of a nitrocellulose membrane filter (MF), impregnated with phospholipid solution in decane, as well as immersed inside it, in the presence of exogenous mediators and disaccharide trehalose, demonstrated an increase in the amplitude and stabilization of the signal under continuous illumination. The ascorbate/N,N,N′N′-tetramethyl-p-phenylenediamine pair and ubiquinone-0 were used as mediators (electron donor and acceptor), respectively. Although the stabilization of photoelectric responses under long-term continuous illumination was observed in both cases of immobilization of chromatophores, only when the samples were immersed inside the MF, the functional activity of the reaction centers was maintained for a month when they were stored in the dark at room temperature. Stable photoresponses are probably associated with the preservation of the integrity of chromatophore proteins inside MF pores. The stabilizing effect of the bioprotector trehalose may be due to both its effect on RC proteins and on the phospholipid bilayer membrane. The results obtained will expand modern ideas about the use of semi-synthetic structures based on various intact photosynthetic systems capable of converting solar energy into an electrochemical form.
Ion channels in electrical signaling in higher plants
Authors: Mudrilov M. A , Ladeynova M. M , Kuznetsova D. V , Vodeneev V. A
Published: April 2024

Electrical signals (ESs) of plants occurring under the action of various external factors play an important role in adaptation to changing environmental conditions. The generation of ESs in higher plant cells is associated with the activation of Ca2+, K+, and anion fluxes, as well as changes in the activity of plasma membrane H+-ATPase. In the present review, the molecular nature of ion channels contributing to ESs transmission in higher plants is analyzed based on the comparison of data from molecular-genetic and electrophysiological studies. Based on such characteristics of ion channels as selectivity, activation mechanism, and intracellular and tissue localization, those ion channels that meet the requirements for potential participants of ESs generation were selected from a wide variety of ion channels in higher plants. Analysis of the data of experimental studies performed on mutants with suppressed or enhanced expression of a certain channel gene revealed those channels whose activation contributes to ESs formation. The channels responsible for Ca2+ flux during ESs generation include channels of GLR family, for K+ flux - GORK, for anions - MSL. Consideration of the prospects for further studies suggests the need to combine electrophysiological and genetic approaches along with the analysis of ion concentrations in intact plants within a single study.
Mitochondrial network: electric cable and more
Authors: Abramicheva P. A , Andrianova N. V , Babenko V. A , Zorova L. D , Zorov S. D , Pevzner I. B , Popkov V. A , Semenovich D. S , Yakupova E. I
Published: April 2024

Mitochondria in a cell can unite and organize complex extended structures that extend over the entire cellular volume, ensuring a uniform supply of energy to cellular compartments with ATP synthesized in the mitochondria. In accordance with the chemiosmotic concept, the energy of oxidation of respiratory substrates is largely stored in the form of an electrical potential difference on the inner membrane of mitochondria. The theory of the functioning of extended mitochondrial structures as intracellular electrical wires suggests that mitochondria provide the fast delivery of electrical energy through the cellular volume, with following use of this energy for ATP synthesis, thereby speeding up the process of ATP delivery compared to the rather slow diffusion of ATP in the cell. The analytical review gives the history of the cable theory, solved and unsolved critical problems, the lability of the mitochondrial network and the role of oxidative stress in this process. In addition to the already proven functioning of extended mitochondrial structures as electrical cables, a few of additional functions are proposed, in particular, the hypothesis is put forward that mitochondrial networks provide a uniform distribution of redox potential throughout the cell, which can change in pathological conditions during fragmentation of the mitochondrial reticulum. A few of pathologies accompanied by a violation of the redox status and the participation of mitochondria in them are considered.
A novel two-domain laccase with a middle redox potential: physicochemical and structural properties
Authors: Trubitsina L. I , Trubitsin I. V , Lisov A. V , Gabdulkhakov A. G , Zavarzina A. G , Belova O. V , Larionova A. P , Tishchenko S. V , Leontievsky A. A
Published: April 2024

The gene for a previously unexplored two-domain laccase was identified in the genome of the actinobacterium Streptomyces carpinensis VKM Ac-1300. A two-domain laccase, named ScaSL, was produced in a heterologous expression system (Escherichia coli strain M15 [pREP4]). The enzyme was purified to homogeneity using affinity chromatography. ScaSL laccase, like most two-domain laccases, exhibited activity in the homotrimer form. However, unlike most two-domain laccases, it was also active in multimeric forms. The enzyme exhibited maximum activity at 80°C and was thermally stable. The half-inactivation time of ScaSL at 80°C was 40 min. Laccase oxidized the non-phenolic organic compound ABTS at a maximum rate at pH 4.7; oxidized the phenolic compound 2,6-dimethoxyphenol at a maximum rate at pH 7.5. Laccase stability was observed in the pH range 9-11. At pH 7.5, laccase was weakly inhibited by sodium azide, sodium fluoride, and sodium chloride; at pH 4.5, laccase was completely inhibited by 100 mM sodium azide. Km and kcat of the enzyme for ABTS are 0.1 mM and 20 s-1, respectively. Km and kcat for 2,6-dimethoxyphenol are 0.84 mM and 0.36 s-1, respectively. ScaSL catalyzed the polymerization of humic acids and lignin. The redox potential of laccase was 0.472 ± 0.007 V. Thus, ScaSL laccase is the first characterized two-domain laccase with a middle redox potential. The crystal structure of ScaSL was determined with a resolution of 2.35 Å. A comparative analysis of the structures of ScaSL and other two-domain laccases suggested that the middle potential of ScaSL may be associated with conformational differences in the position of the side groups of amino acids at position 230 (in ScaSL numbering), which belong to the second coordination sphere of the copper atom of the T1 center.
Microgravity effects and aging physiology: similar changes or common mechanisms?
Authors: Ratushnyy A. Yu , Buravkova L. B
Published: April 2024

Despite the use of preventive measures (including intense physical activity), cosmonauts and astronauts develop muscle atony and atrophy, insufficiency of the cardiovascular system, osteopenia, etc. All these changes, reminiscent of age-related physiological changes, occur in a healthy person in microgravity quite quickly - within a few months. Adaptation to the absence of gravity leads to the symptoms of aging, which are compensated after returning to Earth. The prospect of interplanetary flights raises the question of gravity thresholds, below which the main physiological systems will lose their functional potential, similar to aging, and affect life expectancy. An important role in the aging process belongs to the body’s cellular reserve - progenitor cells, which are involved in physiological remodeling and regenerative/reparative processes of all physiological systems. With age, progenitor cell count and the regenerative potential decreases. Moreover, their paracrine spectrum becomes pro-inflammatory during replicative senescence, disrupting tissue homeostasis. Mesenchymal stem/stromal cells (MSCs) are mechanosensitive, and therefore the absence of a gravitational stimulus causes serious changes in their functional status. The review compares the cellular effects of microgravity and changes developing in senescent cells, including stromal precursors.
Effects of progesterone and selective ligands of membrane progesterone receptors in HepG2 cells of human hepatocellular carcinoma
Authors: Shchelkunova T. A , Levina I. S , Morozov I. A , Rubtsov P. M , Goncharov A. I , Kuznetsov Yu. V , Zavarzin I. V , Smirnova O. V
Published: April 2024

Progesterone exerts multiple effects in different tissues through nuclear receptors (nPRs) and through membrane receptors of the adiponectin and progestin receptor (mPRs) family. The effect of progesterone on cells through different types of receptors can vary significantly. At the same time, it affects the processes of proliferation and apoptosis in normal and tumor tissues in a dual way, stimulating proliferation and carcinogenesis in some tissues, suppressing them and stimulating cell death in others. In this study, we have shown the presence of a high level of mRNA and mPRβ protein in HepG2 tumor cells of human hepatocellular carcinoma. Expression of other membrane and classical nuclear receptors was not detected. May be mPRβ has an important function in HepG2 cells. The main goal of the work was to study the function of this protein and the mechanisms of its action in human hepatocellular carcinoma cells. Previously, we have identified selective mPRs ligands, compounds LS-01 and LS-02, which do not interact with nuclear receptors. Their employment allows differentiating the effects of progestins mediated by different types of receptors. The work studied the effects of progesterone, LS-01 and LS-02 on the proliferation and death of HepG2 cells, as well as the activating phosphorylation of two kinases, p38 MAPK and JNK, under the action of three steroids. It was shown that all three progestins after 72 hours of incubation with cells suppressed their viability and stimulated the appearance of phosphatidylserine on the outer surface of membranes, which was detected by binding to V-FITC annexin, but they did not affect DNA fragmentation of cell nuclei. Progesterone significantly reduced the expression of proliferation marker genes and stimulated the expression of the p21 protein gene, but had a suppressive effect on the expression of some proapoptotic factor genes. All three steroids activated JNK in these cells, but had no effect on p38 MAPK activity. The effects of progesterone and selective mPRs ligands in HepG2 cells were the same in terms of suppression of proliferation and stimulation of apoptotic changes in outer membranes, therefore, they were mediated through interaction with mPRβ. JNK is a member of the signaling cascade activated in these cells by the studied steroids.
Changes in the structure of potato virus A virions during limited proteolysis in situ according to tritium labeling data and computer simulation
Authors: Ksenofontov A. L , Baratova L. A , Semenyuk P. I , Fedorova N. V , Badun G. A
Published: April 2024

The coat proteins (CP) of potato virus A virions (PVA) contain partially disordered N-terminal domains, which are necessary for performing vital functions of the virus. A comparative analysis of the structures of coat proteins (CPs) in intact PVA virions and in virus particles lacking the N-terminal 32 amino acids (PVAΔ32) was carried out in this work based on the tritium planigraphy data. Using the atomic resolution structure of the potato virus Y potyvirus (PVY) protein, which is a homolog of CP PVA, the available CP surfaces in the PVY virion were calculated and the areas of intersubunit/ interhelix contacts were determined. For this purpose, the approach of Lee and Richards (Lee, B., and Richards, F. M. (1971) J. Mol. Biol., 55, 379-400) was used. Comparison of the incorporation profiles of the tritium label in intact and trypsin-degraded PVA∆32 revealed the position of the ΔN-peptide shielding the surface domain (a.a. 66-73, 141-146) and the interhelix zone (a.a. 161-175) of the PVA CP. The presence of channels/cavities was found in the virion, which turned out to be partially permeable to tritium atoms. Upon removal of the ∆N-peptide, a decrease in the label within the virion (a.a. 184-200) was also observed, indicating a possible structural transition leading to virion compactization. Based on the data obtained, we can conclude that part of the surface ∆N-peptide is located between the coils of the virion helix, which increases the helix pitch and provides greater flexibility of the virion, which is important for the intercellular transport of the viruses in the plants.
Chemical and Microbiological Composition of Tom River Bottom Sediments (Yurginskii District, Western Siberia)
Authors: Ovsyannikova V. S. , Russkikh I. V. , Strel’nikova E. B. , Kadychagov P. B.
Published: April 2024

Data of chemical and microbiological analyses of bottom sediment composition of the Tom R. near Yurga Town, Kemerov oblast, are given. All samples of bottom sediments were found to contain organic compounds of mixed, biogenic, and anthropogenic origin with the predominance of the latter. Clayey and silty bottom sediments show a higher content of ash-free substance, heavy metals, practically all classes of identified hydrocarbons, except for oxygen-containing and acyclic compounds. Bottom sediments with sand composition contain minimal concentrations of organic pollutants, and the proportions of hydrocarbons of different origin in them are comparable. Microbiological analysis showed the predominance of hydrocarbon-oxidizing bacteria in bottom sediments composed of clays and silty sand.
Measurement Accuracy in Water Quality Control
Authors: Danilov-Danilyan V. I. , Larina E. G. , Rozental O. M.
Published: April 2024

It is well-known that the error of a measurement result can increase at each step of a laboratory procedure, as well as because of the sample character of partial measurements. To overcome these difficulties, close cooperation between hydrologists and analytical chemists is required in order to obtain reliable information about the composition and properties of natural waters, which are extremely unstable. The study focuses on details that are of importance for both the client-hydrologist and the performer—chemist-analyst. The article gives different variants of conclusions regarding the compliance or non-compliance with the established requirements. The cost of reliable measurements is calculated, and variants of optimization of enterprise’s payments for discharges are proposed. Recommendations are given to customers regarding the choice of a competent analytical laboratory.
Long-Term Variations in Zoobenthos Characteristics in Watercourses on the the Khektsir Ridge
Authors: Yavorskaya N. M.
Published: April 2024

The results of long-term studies are used to present, for the first time, the structural organization of zoobenthos communities and the dynamics of their density and biomass in rivers and brooks of the the Khektsir Ridge, including the boundaries of the Bol’shekhekhtsirskii Reserve, Khektsirskii Wildlife Reserve (the southern part of the Russian Far East). The benthic organisms were found to contain 23 groups (22 groups in the spring and summer, 19 groups in the autumn, and 8 groups in the winter). Leading in the occurrence frequency (90%) were chironomids, mayflies, and oligochaetes. The chironomids and amphipods accounted for 37.0 and 19.1% of the total benthos density, and mollusks and amphipods, for 32.1 and 29.7% of the total biomass, respectively. Dominants in terms of density and biomass were amphipods; chironomids dominated in terms of density, and mollusks, in terms of biomass. The mean density of benthic organisms was 637 ± 21 spec./m2, and the mean biomass was 1.8 ± 0.2 g/m2. The benthic communities of rift segments in the rithral zone were found to be most productive. It is shown that the seasonal and long-term dynamics of zoobenthos communities is pronounced and can be traced in the group composition, structure, and quantitative characteristics.
Anthropogenic Changes in the Hydrochemical Regime and Water Quality in an Urban Watercourse: Case Study of the Likhoborka River, Moscow Region
Authors: Fashchevskaya T. B. , Slovyagina A. N. , Polyanin V. O. , Algushaeva A. V.
Published: April 2024

The article presents the results of hydrochemical monitoring of a small river flowing in an urbanized basin in Moscow. Probabilistic estimate is given to the compliance of river water quality with regulatory requirements and the occurrence of high level river pollution (high and extremely high pollution). Specific features of river hydrochemical regime that distinguish the urban watercourse from natural water objects are revealed. The representativeness of the observation data from the institution that controls river water quality is estimated, and the time step of the series of measured water quality characteristics was shown to be insufficient to fully reflect their variations. The reliability of the monitoring data presented by the control institution is too low to adequately assess the level of river water pollution and the efficiency of the measures taken to protect the river
Current Hydrological Regime of the Volga Reservoirs
Authors: Poddubnyi S. A. , Zakonnova A. V. , Tsvetkov A. I. , Trofinmenko L. T. , Shvets’ N. V.
Published: April 2024

The study is focused on variations of air temperature in the basin of the Volga reservoirs, the total inflow into the water bodies, their water exchange, water level and temperature, and the heat content of water mass in open-water period under various climate conditions. The object of the analysis is the long-term series of hydrometeorological data processed by statistical methods. It is shown that the present-day air temperature has increased by 1.3‒1.8°C compared with the period before 1976. The rate of warming was on the average 0.50°C/10 years. The volume of annual inflow increased by 12.4%. Three low-water and 4 high-water phases were identified in the reservoirs of the Upper Volga, including 29–31 low-water, 25–31 high-water, and 8–16 medium-water years. During the low-water phases, the volume of inflow into the reservoirs is 10–28% less than the long-term average, while in high-water years, it is 4–20% higher. The coefficient of water exchange in the reservoirs decreased or increased by 5–13% relative to the values obtained earlier. An increase in the winter and a decrease in the spring inflow were recorded in the reservoirs of the Upper Volga and in the Kuibyshev Reservoir. A tendency toward an increase in the normal annual water level was observed in the reservoirs in the upper part of the Volga and in the Kuibyshev Reservoir, while in the lower Volga, the normal annual level somewhat decreased. In low-water phases, the reservoir levels were on the average 17 cm below and in the high-water phases, 10 cm above the normal annual value. An increase in air temperature during the warm season in the reservoir water areas, on the average by 1.2°C, led to a synchronous increase in the temperature of the water mass by 1.1°C. At the same time, the heat content of the water mass of the reservoirs increased, on the average, by 24% in the upper part of the Volga and by as little as 2–11% in its lower part
Neural Network Analysis as a Base of the Future System of Water–Environmental Regulation
Authors: Rozental O. M. , Fedotov V. Kh.
Published: April 2024

The article considers neural-network methods and technologies, which are relatively new even for many researchers and experts, as applied to water–environmental regulation. The efficiency of neural networks in this line of studies is due to their self-training, and the ensuing ability to reveal complex nonlinear relationships between the characteristics under control by data processing instruments, consisting of interrelated neurons. The methodology of artificial neural networks and the features of their functioning are described. Training and methodological examples are given to illustrate their potential use. A practical problem, considered as an example of ANN application, is the potential for improving the efficiency of identification of large enterprises polluting natural water among many water users in an industrial region. This is made with the use of data on the concentrations of some priority water-polluting metals at the hydrochemical gages in the Iset river near Ekaterinburg City. The neural-network analysis is shown to detect relationships between individual water quality characteristics at nearby gages. This allowed the conclusion that there exist close logistic economic relationships between water users, which help revealing water pollutants by the water footprint produced by plants working in the same branch. It is also shown that the use of ANN opens new ways for determining the contribution of industrial waste discharges to the level of water pollution by substances of dual genesis (natural and technogenic). The reliability of the conclusions is confirmed by the possibility to use the data on a given hydrochemical gage to satisfactorily predict water quality at a gage further downstream.
Chemical Indication of the Processes of Freshet Runoff Formation in a Small Experimental Catchment in the Prilenskoe Plato, The Republic of Sakha (Yakutia)
Authors: Shamov V. V. , Lutsenko T. N. , Lebedeva L. S. , Tarbeeva A. M. , Efremov V. S. , Pavlova N. A. , Ksenofontova M. I.
Published: April 2024

The article considers the theory, methods, and some results of four-year field studies of the processes of runoff formation on a small freezing experimental river catchment in a continuous thick (400 m) permafrost zone (the Republic of Sakha (Yakutia)) based on data on natural water chemistry. The analyzed problems include the seasonal and daily dynamics of river flow in the warm season, the concentrations of some dissolved substances in different types of water, as well as the role of channel widenings, supra-permafrost water, and aufeises in flow formation. Various types of relationships between water discharges and the concentrations of some dissolved substances are described under varying hydrothermal conditions. The role of nonfreezing lake-like channel widenings (bochags) in the regulation of freshet flow of water and dissolved matter is evaluated. The efficiency of the automated digital registration of the level, temperature, and specific electric conductance of water with a high time resolution at hydrological gages is discussed, especially, as applied to the rapid processes in a river.
A FCM Runoff Model for Small Rivers with Rainfall Recharge. 1. The Concept and Algorithms
Authors: Gartsman B. I.
Published: April 2024

The flood cycle model FCM is a lumped conceptual water-balance model designed to simulate rain runoff at a scale of a small river basin. The development of the FCM model includes the description of the dynamics of the major components of the total moisture reserves of a basin and reproduces the effect of spatial expansion of the drainage network through temporary surface and subsurface streams during extraordinary floods. The accepted conceptual assumptions of the model, which are in agreement with the rational hydrological considerations, lead to three runoff-formation regimes, referred to as intravolume, surface and breakthrough. The concept and algorithms of FCM are given in detail.
Simulating Runoff Regime in a Glaciated High-Mountainous Basin: A Case Study of the Baksan River (Caucasus, Russia)
Authors: Kornilova E. D. , Krylenko I. N. , Rets E. P. , Motovilov Yu. G. , Atabieva F. A. , Kuchmenova I. I.
Published: April 2024

The water resources of the North Caucasus depend mostly on the state of glaciers, which have been intensely losing their mass in the recent decades against the background of climate changes. The deglaciation leads not only to a decrease in the glacier runoff of mountain rivers, but also to changes in the annual distribution of runoff. The focus of this study is the adaptation of ECOMAG software complex to simulating river runoff in the Baksan River basin based on data on the relief and underlying surface of the drainage basin (soil, vegetation) and daily data on the surface air temperature, air saturation deficit, and precipitation. The calibration and validation of the model and the statistical estimate of calculation efficiency were based on the data on water discharges in the Baksan River over 2000–2017. The developed model of runoff formation in the Baksan River basin was used to carry out numerical experiments for assessing the sensitivity of runoff characteristics to glacier area variations. Depending on the rate of deglaciation process, the runoff of the Baksan River can drop by 10–30% because of a decrease in its glacial component, and the maximal water discharges can drop by 10–15%.