2026 Issue №2

The use of peptides is associated with certain challenges. Due to proteolytic instability and a short plasma half-life, peptides require the development and application of specialized delivery systems, which often limits their use to parenteral administration routes. Low bioavailability following oral administration further complicates the clinical use of peptides, especially in chronic diseases requiring patient-friendly treatment regimens. The aim of the study was to develop, synthesize, and characterize a peptidomimetic for oral administration with nonspecific immunomodulatory activity, as well as to assess its cytotoxicity and effect on DC proliferation. The object of the study was a peptidomimetic designated CD-17 with the following amino acid sequence: CTSIGGAGTCPPICFFD. It was established that there are no matches between the amino acid sequence of CD-17 and known peptides or peptidomimetics, which indicates the uniqueness of the developed peptidomimetic. The physicochemical properties and structure of the peptidomimetic were predicted. According to the APD database, the total net charge of CD-17 is – 1, the peptide hydrophobicity according to the Wimley–White method (i. e., the sum of the transfer energy of the peptide without the whole residue from water to the POPC interface) is 0.86 units, the molecular weight is 1688.97 Da, the molecular formula of the peptide is C73H109N17O23S3, and the protein-binding potential (Boman index) is 0.41 kcal/mol. It was established that CD-17 is a biologically active peptidomimetic and belongs to the DILI-negative category, i. e., it is safe for the liver. Prediction of the acute oral toxicity of CD-17 in rats demonstrated that the peptidomimetic does not exhibit acute toxicity (non-toxic at doses > 500 mg/ kg). The VDss of CD-17 is 0.879 with an optimal range of 0.04—20, while Fu is 89.24 % with an optimal value of ≥ 20. CD-17 demonstrates excellent CL and a moderate half-life. It was established that after three days of cultivation with the peptidomimetic, the number of DCs was 23.07 % higher (p < 0.05) compared with the negative control.

Using the example of 10 micromycete strains, including museum strains of Alternaria alternata, Alternaria solani and Alternaria infectoria, as well as isolates obtained from natural samples (soil, potato tubers, and wheat seeds), the ability of micromycetes of the genus Alternaria to synthesize endogenous and exogenous lectins was established. Micromycetes of the genus Alternaria are capable of synthesizing both exogenous and endogenous lectins. It was established that the lectin activity of the studied Alternaria micromycete strains is significantly lower than that of micromycetes of the genus Fusarium. Nevertheless, it was possible to increase the lectin activity titer of Alternaria micromycetes by 2—8 times through treatment of the erythrocyte surface with neuraminidase. Among the new isolates of Alternaria micromycetes, the strain Alternaria alternata 4 (grain) synthesizing lectins with the highest activity titer (512 units) was selected. To confirm its belonging to the genus Alternaria, a molecular genetic analysis was performed, which demonstrated that the obtained strain belongs to the phylum Ascomycota, class Ascomycetes, subclass Dothideomycetidae, order Pleosporales, family Pleosporaceae, species Alternaria alternata. Comparison of the activity titers of exogenous and endogenous lectins demonstrated the predominance of intracellular lectin synthesis, making these forms the most promising for further research.

The Amur Region is a major agricultural area of the Russian Far East with a high rural population density. In most cases, water from decentralized sources is used for drinking, household, and domestic purposes. The scientific literature lacks data on the current state of groundwater in the most intensively exploited part of the region, the Amur–Zeya Plain. The quality of drinking water from decentralized water supply sources in the agricultural districts (Tambovsky, Konstantinovsky, and Arkharinsky) of the Amur Region was assessed. Water samples were collected in accordance with GOST R 59024-2020 during the period from March to May 2025. The depth of the wells ranged from 90 to 250 m. The investigated sources were deep tubular wells used for individual purposes. The study of groundwater composition was carried out in the environmental chemistry laboratory of Благовещенский State Pedagogical University using the capillary electrophoresis method with the “Kapel 205” capillary electrophoresis system; cation composition was determined according to FERD 14.1:2:4.167-2000 (Federal Environmental Regulatory Documents), anion composition according to FERD 14.1:2:3:4.282-18, and pH according to RD 52.24.495-2017. The obtained results were compared with SanPiN 1.2.3685-21 standards. In the water of the settlements of Kuropatino and Arkhara, MPC exceedances for nitrites were identified, while water from Lozovoye and Kuropatino showed exceedances for lithium and potassium, respectively. Water samples from the settlements of Kositsino and Otvazhnoye contained elevated concentrations of nitrite ions and barium ions. Water collected from wells in Novopetrovka contained high concentrations of lithium and barium cations. Water from decentralized water supply sources in the village of Sadovoye did not comply with standards for six indicators. Exceedances were identified for nitrite and nitrate ions, fluorine, potassium, phosphates, and barium. In general, it should be noted that elevated concentrations of barium cations and nitrite ions were identified in the Tambovsky, Konstantinovsky, and Arkharinsky municipal districts.

The global decline of honey bee (Apis mellifera) populations poses a serious threat to crop pollination and global food security. Among the multiple factors causing colony weakening and loss, varroosis, an invasive disease caused by the ectoparasitic mite Varroa destructor, plays a pivotal role. Despite decades of research and various control methods, effective management of this parasite remains elusive. The aim of this work was a comprehensive analysis of the genetic structure of V. destructor populations infesting Carpathian bee colonies (A. m. carpatica) in the Republic of Tatarstan, within the framework of the parasite’s genetic lability and adaptive potential. Sequencing of the mitochondrial cox1 gene fragment and phylogenetic analysis using the Neighbor-Joining method with 103 reference sequences from GenBank were performed. The studied samples were found to belong to the Korean (K) haplotype. The identified single nucleotide polymorphism (A/T transversion) in two samples indicates intrapopulation genetic differentiation. It is shown that the genetic lability of the parasite, manifested in the existence of multiple genovars within one colony and their ability to rapidly shift dominant haplogroups under selective pressure, is an underestimated factor reducing the effectiveness of acaricide treatments and the selection of resistant bee breeds. Behavioral adaptations of the mite, including its ability to modify the host’s cuticular hydrocarbon profile and change trophic preferences depending on population density, are discussed. The obtained data substantiate the need for regular molecular genetic monitoring of V. destructor population structure as an essential element of the veterinary and sanitary surveillance system in beekeeping.

The results of a comprehensive analysis of the genetic diversity of the microsporidian Nosema apis, the causative agent of nosemosis in honey bees (Apis mellifera), are presented using the example of a single apiary located in the Laishevsky District of the Republic of Tatarstan. Identification of the haplotypic composition of the pathogen and assessment of its phylogeographic relationships with Eurasian isolates were carried out based on the polymorphism of the polar tube protein gene PTP3. It was established that all examined bees were infected with N. apis. Sequencing and subsequent cloning of heterozygous samples revealed the presence of two amino acid variants of the PTP3 protein within a single hive. One of them completely coincided with the dominant Eurasian haplotype previously described in parasite populations from Slovenia, Spain, and Turkey. The second variant is unique to the present study and differs from the main variant by a single nonsynonymous substitution (leucine instead of proline at the position presumably corresponding to codon 112 of the protein). A weak positive correlation was identified between high invasion intensity (spore load > 150 thousand spores) and the belonging of bees to hybrid forms involving the Central Russian and Grey Mountain Caucasian breeds (r = 0.25; p < 0.05).