Doklady Rossijskoj akademii nauk. Nauki o žizni

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.