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Volume 521, Nº 1 (2025)
Articles
Microstructure of hair of the mummy of a juvenile saber-toothed cat – Homotherium †Homotherium latidens (Felidae, Carnivora)
Resumo
For the first time, the microstructure of hairs from different parts of the body of a three-week-old kitten of the Pleistocene Homotherium †Homotherium latidens was studied using light and scanning electron microscopy (SEM). Its frozen mummy, aged 31,808–37,019 years, was found in Yakutia and first described by Russian paleontologists [1]. According to our data, Homotherium had poorly differentiated short uniform tangled dark-brown fur, the heat-protective properties of which were not high due to the weak development of the hair medulla, but their mechanical strength was excellent. The microstructure of Homotherium hair differs depending on the location of the hairs on the animal’s body. Comparison of the obtained data with information on the fur of kittens of cave and African lions shows similarities and differences in the microstructure of hairs in these species, which is explained functionally.
Doklady Biological Sciences. 2025;521(1):173-179
173-179
Ontogeny of the epileptic system in rats of the Krushinsky–Molodkina line with genetically determined audiogenic epilepsy
Resumo
The development of convulsive proneness of audiogenic epilepsy (AE) and phenotype manifestations of epileptic activity in rats of the Krushinsky – Molodkina (KM) strain, proceeds in parallel with the appearance of seizure EEG patterns followed in this investigation from the age of 2 months age up to 7 months (both in КМ rats). The latencies of the seizure onset reduced with age while the intensity of convulsive seizures increased. In background EEG (no exposure to sound) of KM rats two types of epileptiform discharges (ED) were identified. The first type had the form of high-amplitude generalized “packs” of waves, with animal shuddering. The second type of ED had the form of a generalized non-seizure absence-like “spike-wave” discharges with animal freezing. The duration of single absence-like discharges increased with age. The parallel age-related changes were found between the increase in severity of AE seizure and the increase of generalized absence-like discharges numbers in the forebrain EEG of KM rats, which evidence the development of epileptic system in this strain.
Doklady Biological Sciences. 2025;521(1):180-186
180-186
Comparative study of the landlocked seals' genetic diversity
Resumo
For the first time, genetic diversity of neutral markers (15 microsatellite loci) was assessed for two species of the landlocked seals: Baikal seal (Pusa sibirica) and Caspian seal (P. caspica) in comparison with the oceanic species of the genus – ringed seal (P. hispida). The study found that both landlocked seals exhibit a reduced level of genetic diversity, with the Baikal seal having the lowest level. Both the Baikal seal and Caspian seal show a high probability of historical bottleneck effect, while the studied population of ringed seals showed no signs of a sharp decline in the past. Analysis of the data using the VarEff package suggests a different time to the most recent common ancestor for each of the three studied populations; for the Baikal seal this time is significantly shorter than for the Caspian seal.
Doklady Biological Sciences. 2025;521(1):187-192
187-192
Search and verification of Betula nana L. hybrid samples in the Urals
Resumo
Using the flow cytometry method, hybrid samples were verified in B. nana populations, most of which were identified in the northern part of the Ural Mountains. Analysis of the ITS1 region nucleotide sequences obtained using the Sanger method showed low differentiation of B. nana and B. pubescens species associated with current and ancestral hybridization processes. Analysis of intragenomic polymorphism of ITS1 sequences using Illumina technology revealed the presence of rDNA of both B. nana and B. pubescens in first-generation interspecific hybrids genome.
Doklady Biological Sciences. 2025;521(1):193-197
193-197
Targeted therapy in combination with an agent that enhances terminal differentiation of cancer cells
Resumo
Currently, for the treatment of oncological diseases, in addition to standard treatment methods, an approach is being developed in which terminal differentiation of cancer cells is induced with the help of pharmacological drugs, leading to an increase in the therapeutic effect under the influence of traditional treatment methods. A number of examples of the use of dimethyl sulfoxide (DMSO) as a safe adjuvant that stimulates the differentiation of various types of the cancer cells, have been described in the literature. In this paper, we propose a method for elimination of human ovarian cancer cell adenocarcinomas SKOV3.ip1, including targeted therapy based on the HER2-specific toxin DARP-LoPE and DMSO as an enhancing agent for terminal differentiation of cancer cells.
Doklady Biological Sciences. 2025;521(1):198-203
198-203
Optimization of A549 cell transfection efficiency with a plasmid encoding the N-protein of the SARS-CoV-2 virus
Resumo
To test new antiviral drugs aimed at degrading the nucleocapsid protein (N-protein) of the SARS-CoV-2 virus, it is desirable to have cells expressing the N-protein, for which it is necessary to find conditions for the maximum achievable efficiency of cell transfection with a plasmid encoding this protein. For transfection, polyplexes were used consisting of a plasmid encoding the N-protein fused with the mRuby3 fluorescent protein and polyethyleneimine (PEI)-polyethylene glycol (PEG)-TAT peptide block copolymers. The dependence of the transfection efficiency of human lung adenocarcinoma A549 cells on the PEG/PEI and N/P ratios (the ratio of nitrogen in PEI to phosphate in DNA) was studied. Significant positive correlations were shown between transfection efficiency determined by flow cytometry, the N/P ratio, and the proportion of polyplexes sized 40–54 nm. The data obtained can serve as a basis for creating an animal model of lung cells transiently expressing the N protein of the SARS-CoV-2 virus.
Doklady Biological Sciences. 2025;521(1):204-207
204-207
Changes in the repertoire of extracellular vesicles secreted by skin keratinocytes by the human protein SLURP-2
Resumo
Extracellular vesicles secreted by keratinocytes are participants of intercellular interactions, and contain various proteins, mRNA and miRNA, lipids, due to which they can activate cell migration and proliferation. The secreted human protein SLURP-2 regulates growth and differentiation of epithelial cells, affects proliferation and migration of keratinocytes. In this work, we showed that extracellular vesicles secreted by keratinocytes in presence of SLURP-2 stimulate migration of HaCaT keratinocytes. It was also found that, expression of miRNA-96 and miRNA-183, suppressing cell migration and proliferation, is decreased in the vesicles secreted by keratinocytes in presence of SLURP-2. Thus, it has been shown that the stimulation of keratinocyte migration in presence of SLURP-2 is associated, among others, with a change in the repertoire of extracellular vesicles secreted by these cells.
Doklady Biological Sciences. 2025;521(1):208-213
208-213
Increasing the accumulation of modular nanotransporters in mouse tumors by attaching polyethylene glycol to these nanotransporters with the possibility of its release into the tumors
Resumo
Previously, polypeptide constructs – modular nanotransporters (MNT) – were created to deliver biologically active molecules into the nuclei of melanoma cells. In the present work, polyethylene glycol (PEG) molecules were attached to them at the N-terminal cysteine, both with the possibility of their subsequent cleavage at the hydrolysis site of tumor-specific proteases, and without this site (non-detachable PEG). All MNT variants labeled with the radioisotope 111In were administered to mice with inoculated Cloudman S91 melanoma. The kinetics of radioactivity distribution in the mouse body was studied using single-photon emission computed tomography. Analysis of the obtained data using a compartmental mathematical model allowed us to establish that the attachment of PEG to MNT increased its lifetime in the blood and significantly increased its accumulation in the tumor. Addition of a PEG detachment site by tumor-specific protease led to a strong retention of this MNT in the tumor. The data obtained can serve as a basis for the creation of new effective antitumor drugs.
Doklady Biological Sciences. 2025;521(1):214-218
214-218
Investigation of the functional role of the conserved sequence at the 5’-end of the fourth intron of the mod(mdg4) gene in trans-splicing in Drosophila melanogaster
Resumo
Alternative splicing is an important mechanism that provides genetic diversity of proteins. Unique loci have been identified in Drosophila melanogaster, where mRNA diversity arises as a result of trans-splicing — a process in which exons from different pre-mRNAs are joined together. The trans-splicing in the mod(mdg4) locus, which encodes more than 31 isoforms, has been studied in detail. Important elements for this process include previously described conserved sequences in the fourth intron. The aim of this study is to further characterize the conserved motifs of the fourth intron, specifically the element at the 5’-end of the intron. Using model transgenic lines, it has been shown that introduced changes in the sequence of the studied element lead to a disruption of trans-splicing. In contrast, similar changes in the endogenous locus did not result in a disruption of trans-splicing. Thus, the conserved element plays a role in trans-splicing but is not critical.
Doklady Biological Sciences. 2025;521(1):219-224
219-224
Modular nanotransporters containing Keap1 monobodies are capable of reducing the toxic effect of acetaminophen on the liver of mice
Resumo
Previously, we created a modular nanotransporter (MNT) containing a monobody to Keap1, an intracellular protein inhibitor of the Nrf2 transcription factor that controls cellular protection from oxidative stress and is capable of interacting with Keap1 in hepatocytes and protect this cells from the effects of hydrogen peroxide. Oxidative liver damage by acetaminophen was used as a model to study the antitoxic effect of this MNT. Intraperitoneal injection of acetaminophen to mice resulted in an increase in the level of alanine aminotransferase and aspartate aminotransferase in the blood, as well as in liver edema. A significant decrease in the level of these enzymes in the blood, along with a decrease in liver edema, was observed after preliminary intravenous administration of MNT 2 hours before the acetaminophen injection. The results obtained can serve as a basis for creating drugs aimed at treating diseases associated with oxidative stress.
Doklady Biological Sciences. 2025;521(1):225-228
225-228
Identification of a highly conserved region critical for the functionality of the CP190 protein in Drosophila melanogaster
Resumo
The CP190 protein binds to both housekeeping gene promoters and insulator/boundary elements and plays a critical role in their activity. The aim of this work was to study the effect of deletions in highly conserved regions of the CP190 protein on its functionality. It was shown that deletion of the sequence from 664 to 700 aa leads to a lethal phenotype. Thus, a new region was identified in CP190 that plays an important role in the interaction of the CP190 protein with as yet unidentified partner proteins, stabilization of protein complexes formed by CP190 and their recruitment to chromatin.
Doklady Biological Sciences. 2025;521(1):229-234
229-234
The bxd PRE from Bithorax complex of Drosophila melanogaster has weak insulator activity
Resumo
The autonomous functioning of regulatory domains in the Bithorax complex (BX-C) of Drosophila melanogaster is maintained by boundaries (insulators) that prevent inappropriate enhancer–promoter interactions. Polycomb response elements (PREs) maintain epigenetic memory within regulatory domains and are often located near insulators, enhancing their blocking activity. The bxd PRE is a well-characterized silencer that regulates the bxd/pbx domain of the Ubx gene in the first abdominal segment. We used a boundary replacement strategy to assess the insulator activity of the bxd PRE. Substituting the bxd PRE for the Fab-7 boundary, which separates the Abd-B regulatory domains in the BX-C, revealed that the bxd PRE has weak insulator activity.
Doklady Biological Sciences. 2025;521(1):235-239
235-239
The role of photobiomodulation therapy in reducing stress-induced changes in the hippocampus of rats during septoplasty modeling
Resumo
The aim of the study. To study the effect of photobiomodulation therapy (PBMT) on the amount of p53 in neurons of the pyramidal layer of the hippocampus after modeling septoplasty in rats. Materials and methods. Septoplasty was modeled in 48 Wistar rats. In the postoperative period, PBMT was administered to 24 rats in the early postoperative period for 2 to 6 days. Histological sections of the hippocampus were studied to determine p53-positive neurons on days 2, 4 and 6 after surgery in rats of both groups. Results. Compared with the control group (n=5 rats), in both experimental groups there was an increase in the number of p53-positive neurons in the hippocampus, however, in the group where PBMT was performed in the early postoperative period after modeling septoplasty, the number of such neurons was lower, and in some subfields of the hippocampus on day 6 it even corresponded to the control group. Conclusion. The use of PBMT in the early postoperative period after modeling septoplasty helps to reduce stress-induced expression of the p53 protein in the pyramidal layer of the hippocampus in rats.
Doklady Biological Sciences. 2025;521(1):240-245
240-245
Development of an anchor bispecific nanoantibody to improve the efficiency of antigen immobilization and detection in a well of a polystyrene plate
Resumo
Immunoassay (IA) methods performed in the wells of a polystyrene microplate are the basis of diagnostic studies. In the “sandwich” IA, a fundamentally important initial stage is the immobilization of anchor antibodies in the well of the plate, designed for specific binding of a given antigen from a biological fluid. One of the very promising options for antigen-recognizing molecules are single-domain antibodies (nanoantibodies, Nb). The use of Nbs as anchor antibodies is hampered by their low efficiency of functioning after passive adsorption in the well of the plate. The development of a new format and immobilization method in the case of NT are fundamentally important for overcoming this problem. This work describes the development of a new format of an anchor bispecific nanoantibody (anchor-Nb) to improve the efficiency of both passive adsorption of anchor-NT and subsequent stages of immobilization and detection of the target antigen in the well of a polystyrene plate.
Doklady Biological Sciences. 2025;521(1):246-252
246-252
New kinase inhibitors that are selectively cytotoxic for tumor cells
Resumo
To search for substances selectively acting on tumor cells, phenotypic screening in a coculture of tumor cells with non-tumor cells was used in the work. The compound STOCK7S-36520, selectively cytotoxic in the coculture of breast tumor cells MCF7’ and non-tumor MCF10A, contains structural elements characteristic of kinase inhibitors. Analyzing the compound STOCK7S-36520 and its derivative STOCK7S-47016, it turned out that they are new multikinase inhibitors. The highest inhibition of 84% was shown by compound STOCK7S-47016 against GCK kinase. Of interest is the significant selectivity of action against some of the cell lines studied: the selectivity index of STOCK7S-36520 against the prostate tumor cell line PC3 is 29 times compared to the model line of non-tumor fibroblasts VA13.
Doklady Biological Sciences. 2025;521(1):253-259
253-259
Physiological effect of 24-epibrassinolide and its conjugate with succinic acid on the resistance of rapeseed plants to chloride salinity
Resumo
It has been shown for the first time that exogenous 24-epibrassinolide (EBL) and a conjugate synthesized on its basis, which is 2,3,22,23-tetraester of EBL and succinic acid, at a concentration of 10 nM almost equally mitigate the negative effects of salt stress (150 mM NaCl) on rapeseed plants, maintaining photosynthetic activity and growth parameters. Specificity of the action of the studied compounds in regulating the resistance of rapeseed plants to NaCl is noted. EBL against the background of chloride salinity increases the content of carotenoids, superoxide dismutase and peroxidase activity, while conjugate EBL increases only peroxidase activity. Pretreatment of plants for 4 hours before stress was more effective than the introduction of the studied regulators simultaneously with the stressor.
Doklady Biological Sciences. 2025;521(1):260-267
260-267
Regenerative potential of platelet-rich plasma in diabetes mellitus
Resumo
The study explores in vitro the regenerative potential of platelet-rich plasma (PRP) from patients with type 1 diabetes mellitus: in a series of experiments they add PRP to the culture medium of dermal fibroblasts and evaluate in dynamics the metabolic (including the production of reactive oxygen species), migration and proliferation activity of the cells, and they also determine the growth factors and exosomes levels in PRP and the medium. They reveal a decrease in the proliferative, prooxidant and toxic effects of PRP from patients with diabetes mellitus. They are characterized with a decrease in metabolic activity and cell viability in culture with an increase in the percentage of necrosis, while the migration properties of the cells were not impaired. The presence of diabetes mellitus in a patient is also accompanied by a decrease in the stimulating effect of his PRP on dermal fibroblasts in the secretion of growth factors. These effects were most significant in elderly people with diabetes.
Doklady Biological Sciences. 2025;521(1):268-279
268-279
Structure of the shell wall of Raskiniella plana (subclass Spirillinana)
Resumo
Among the four classes of multicameral foraminifera with a secretive calcareous shell wall, the ultrastructure of the wall is known in three of them – in the classes Rotaliata Mikhalevich, 1980, Miliolata Saidova, 1981 and Nodosariata Mikhalevich 1992. It was believed that the wall of Spirillinata Mikhalevich, 1992 was formed by one or more large crystals. In this study, it was found that in one of the typical representatives of this class, Raskiniella plana (previously classified as Spirillina plana, Wiesner, 1931), the entire shell is formed by amorphous (not crystalline) CaCO3. Previously, amorphous calcareous skeletons were known in some unicellular algae and multicellular eukaryotes, but in foraminifera, the skeleton of the entire adult shell, completely formed by the amorphous form of CaCO3, was discovered for the first time.
Doklady Biological Sciences. 2025;521(1):280-284
280-284
Unusual pattern of cerebral electrical activity in the Mongolian hamster (Allocricetulus curtatus) during heterothermia
Resumo
Electroencephalogram (EEG), brain and abdominal temperature, and motor activity were recorded for the first time in 18 adult males of facultative hibernator, the Mongolian hamster, during hibernation under controlled laboratory conditions in winter. At room temperature, clear synchronous circadian rhythms of motor activity and body temperature were observed. In most animals, a gradual decrease in external temperature (from 24°C to 4°C) led to a significant increase in motor activity, combined with an increase in the amplitude of circadian oscillations of body temperature. Six hamsters demonstrated torpor bouts and hibernation with radical changes in the EEG up to reaching the isoelectric line, as well as the disappearance of oscillations of brain temperature. It has been found that Mongolian hamsters can easily enter and exit both a state of torpor and a fairly deep hibernation with a decrease in body temperature down to 10ºC during normal sleep periods.
Doklady Biological Sciences. 2025;521(1):285-292
285-292
Types of pesticides interaction in mixtures: results of inhibitory analysis
Resumo
Enzymatic inhibitory assay based on the coupled enzyme system NAD(P)·H:FMN oxidoreductase and luciferase (Red + Luc), originally developed for environmental monitoring of soils, water and air, is proposed as a method for evaluating changes in the properties of active ingredients of pesticide preparations depending on the additional components (formulants), as well as when pesticides are combined in mixtures. Using the commercial pesticide preparations containing glyphosate it was shown that the degree of inhibition of the coupled enzyme system Red + Luc is depended on the formulants rather than the active ingredient in their composition. Moreover, the combined inhibitory effect of the pesticides in a mixture was not additive. According to the results of the inhibitory assay, the type of interaction of pesticide preparations in mixtures depends on both the formulants used and the ratio of pesticides in the mixture.
Doklady Biological Sciences. 2025;521(1):293-298
293-298
Mycobiota of acorn worm Saccoglossus mereschkowskii (Hemichordata, Enteropneusta) and its habitats
Resumo
It is known that the tissues and mucous of acorn worms contain phenolic compounds, which inhibit the activity of aerobic bacteria. In this work, the mycobiota of tissues, body surface lavages, and burrows of the acorn worm Saccoglossus mereschkowskii (Wagner, 1885) were studied. 3 species of fungi were found in the plating of intestine samples. 7 species were isolated from the body surface lavage of S. mereschkowskii. 5 species were found in burrow samples, and 15 species were found in the samples of sediment from the habitat of S. mereschkowskii. Plating of intact specimens, gill bars, and axial organ did not reveal the growth of mycelial fungi. This indicates that enteropneust tissues may have a fungistatic effect.
Doklady Biological Sciences. 2025;521(1):299-304
299-304
Architecture of the mammalian vibrissae medulla: polymorphism and nomenclature
Resumo
For the first time, scanning electron microscopy was used to identify, study, and systematize the architecture of the vibrissa medulla in 101 species from 80 genera belonging to eight orders of Mammalia using an original nomenclature. The wide variability of its architecture is due to the diversity of sizes and relationships of the internal compartments of the vibrissae (air cavities and partitions). Different types of medulla were established: membranous, pyramidal, blocky cylindrical, blocky polyhedral, chaotic, small cellular, large cellular, star-shaped, uniserial, and hollow. Medulla of different types can be combined in one vibrissa. In a number of species that lead an underground (moles, mole rats), semi-aquatic (desman) and aquatic (bowhead whale) lifestyle, the medulla in the vibrissae is absent.
Doklady Biological Sciences. 2025;521(1):305-313
305-313