Vol 23, No 3 (2025)

Background: The gut microbiota is one of the main factor influencing the immunity of animals, including fish. Understanding the taxonomic and quantitative composition of the microbiota may hold the key to enhance fish immunity against bacterial and fungal infections in aquaculture that potentially could optimize fish farm management.

Aim: The aim of this work is to determine the taxonomic composition differences of the gut microbiome between healthy and Saprolegnia-affected breeders of broad whitefish (Coregonus nasus, Pallas, 1776) under industrial farming conditions using high-throughput sequencing.

Methods: The gut microbiota composition was analyzed using NGS sequencing and the methods of bioinformatics. Hematological profiling was performed using standard microscopy-based techniques.

Results: Preliminary data from high-throughput molecular genetic screening of the gut microbiota diversity in healthy and Saprolegnia-affected C. nasus individuals during the spawning period are presented. The hematological profile reliably distinguishes clinical differences between healthy fish and those infected with Saprolegnia. Differences in the taxonomic and quantitative composition of the gut microbiomes in C. nasus has been shown.

Conclusion: Fish with the clinical signs of saprolegniosis showed a dominance of the phylum Proteobacteria (on average of 45.3%). There were comparable propotions (26.67–30.27%) of Proteobacteria, Firmicutes, and Actinobacteriota observed in healthy fish.

Background: The study of the spontaneously fermented sourdough microbiome is currently receiving considerable attention worldwide. However, the taxonomic structure of the Russian spontaneously fermented sourdough microbiome remains insufficiently studied using metagenomic methods, despite the important role of the microbiome in ensuring bread quality and safety.

Aim: The aim of the work was to study the dynamics of Russian spontaneous sourdoughs microbial communities during long-term propagation. The objects of the study were eight starter cultures of spontaneous fermentation: four thick rye and four liquid rye starter cultures without brewing.

Methods: Four batches of rye flour of different grades (“wallpaper” and “stripped”) were used to prepare the starter. The composition of microbial communities was determined using high-throughput sequencing of fragments of the 16S rRNA gene.

Results: It was shown that during the sequential refreshing of starter cultures, the proportion of representatives of proteobacteria decreases, while the proportion of Firmicutes increases. The changes in the bacterial community coincided with a decrease in the pH of the starter culture, as well as a significant change in the odor of the starter culture from an unpleasant putrid to a pronounced pleasant odor of the starter culture. The mature starter cultures were dominated by representatives of the Firmicutes type, mainly represented by lactic acid bacteria of the Lactobacillaceae family. It was found that in the process of sequential renewal of starter cultures with water-flour nutrient mixtures, a significant change in the taxonomic structure of the starter microbiome occurs at the level of the Lactobacillaceae family. Namely, the relative abundance of the genera Latilactobacillus, Levilactobacillus, Lactiplantibacillus, Weissella, Pediococcus, Leuconostoc, Lactococcus, Enterococcus, characteristic for young ferments of spontaneous fermentation, decreased, with a simultaneous increase in Fructilactobacillus and Companilactobacillus in dense starter cultures, and Limosilactobacillus and Fructilactobacillus—in liquid starter cultures without brewing. Lactobacilli Fructilactobacillus sanfranciscensis and Companilactobacillus sp. dominated in mature thick rye starter cultures; Limosilactobacillus pontis prevailed in liquid rye starter cultures without welding on stripped flour; L. pontis and F. sanfranciscensis prevailed in wallpaper flour.

Conclusion: As a result of the conducted studies, there were no statistically significant differences in alpha or beta diversity between the starter cultures bred using different grades and batches of flour. It has been shown that the parameters of Russian starter culture management (humidity, temperature), which differ from those accepted abroad, have a decisive influence on the formation of the microbiome of starter cultures of spontaneous fermentation at the level of lactobacillus species.

Background: Most terrestrial plants form a symbiosis with arbuscular mycorrhizal fungi. Arbuscular mycorrhiza significantly enhances plant growth and their adaptation to biotic and abiotic stress factors. Arbuscular mycorrhizal fungi help plant uptake and improve the water nutrition of host plant. At the same time, the regulation and transport of water in plants is largely determined by the aquaporins activity. The specificity of gene expression of these transporters in different plant species and in different tissues has not been fully studied.

Aim: To evaluate the effect of mycorrhization of black medic by arbuscular mycorrhizal fungus on the expression of aquaporin genes in the roots under drought conditions at the early and late stages of symbiosis development.

Methods: Medicago lupulina MlS-1 line, characterized by high response to mycorrhization, was selected by the authors and was used in this study. The effective Rhizophagus irregularis RCAM00320 strain was used for mycorrhization. The plants were watered daily by 0.6 volumes of saturated water content. But during one week before the results were recorded, water scarcity conditions were created, 0.4 volumes of saturated water content. The plants were counted on the 24th and 48th days after sowing and inoculation. Total RNA from plant roots was isolated using the trizole method with modifications. Thirty-three aquaporin genes were selected to analyze the expression levels. Changes in gene expression were assessed using the real-time polymerase chain reaction method.

Results: It was shown the key genes involved in the mechanism of adaptation of mycorrhizal plants to drought may be NIP and TIP aquaporin genes, namely: MlNIP1;2, MlNIP1;3, MlNIP1;5, MlNIP4;1, MlNIP4;2 genes (mainly at the stage of the second leaf development) and MlTIP1;1, MlTIP1;4, MlTIP2;1, MlTIP2;2, MlTIP2;3, MlTIP3;1, MlTIP4;1, MlTIP5;1 genes (mainly at the flowering stage) in plant-microbial system “M. lupulina + R. irregularis”. The study used previously obtained data on the M. lupulina transcriptome to select target genes.

Conclusion: The genes involved in the development of effective symbiosis of plants with arbuscular mycorrhizal fungi in conditions of drought were identified. New information about the mechanisms of effective symbiosis formation is of practical importance for the development of highly productive plant-microbial systems, which will allow the transition from intensive agricultural technologies to biological agriculture with the production of environmentally safe products.

Unstable chromosomal aberrations are key indicators of damage to the genome caused by radiation and chemical factors. Despite a significant number of publications, there is no generalized picture of the prevalence of unstable chromosomal aberrations among the population, especially among high-risk groups associated with industrial activities, environmental pollution and emergency situations. The results of the study are important for an objective assessment of the consequences of large accidents, technogenic disasters and changes in the environmental situation that affect human health. Current paper is devoted to the review of literature sources that contain the data on the dynamics of unstable chromosome aberration in people affected by radiation and chemical exposure. It also deals with the frequency of unstable chromosome aberrations in unexposed individuals that compose the comparison group for the exposed people in various regions of the Russian Federation and some foreign countries. The studies reviewed cover a wide period of time, both short-and long-term effects of exposure, and include the analysis of different situations of radiation damage and chronic chemical exposure. The paper presents the comparative data on the frequency of unstable chromosome aberrations in the control groups and groups of exposed individuals that demonstrate different patterns of body response to external mutagens. The results of the studies emphasize that there is still the need to evaluate chromosome aberrations that develop in people under the effect of radiation and chemical factors. The importance of unified standards of unstable chromosome classification and measurement is also highlighted. It will improve the precision and comparability of the research findings.

Oxidative stress is a major factor in the development and progression of polycystic ovary syndrome. It drives metabolic disturbances, systemic inflammation, and ovarian dysfunction. Excessive production of reactive oxygen species, combined with weakened antioxidant defenses, exacerbates insulin resistance, hyperandrogenism, and impaired folliculogenesis. Genetic variations in antioxidant genes further influence this imbalance, shaping individual susceptibility to the syndrome. His review summarizes the role of key antioxidant defense genes, including SOD2, GPX1, GPX4, CAT, and PON1, and examines their associations with polycystic ovary syndrome risk and clinical outcomes. Polymorphism, such as SOD2 rs4880 and GPX4 rs713041 show relatively consistent links with polycystic ovary syndrome, whereas other variants display population-specific effects. Understanding the genetic basis of oxidative stress may advance biomarker discovery and support the development of personalized therapeutic strategies for women with this disease. The development of precision therapy protocols for this syndrome, taking into account genetic testing and lifestyle data, will help improve the reproductive and metabolic health of women with polycystic ovary syndrome.

The biological concept of “stress”, set out in the works of G. Selye, created an entire scientific direction. It has played and continues to play a major role in the development of biomedical research. Scientific progress leads to filling the term “stress” with new biological content at different levels of study. At the same time, unjustified expansion often leads to a blurring of the concept, clogging with “cryptic” terms that complicate the understanding of the phenomenon. The purpose of the work is to discuss some points that complicate or distort the scientific content of the term “stress”. It seems appropriate to consider stress as a non-specific marker of damage to the organism. It should not be used to describe various non-specific changes caused by routine strain that any living organism constantly experiences. From a genetic point of view, it is proposed to consider the stress phenomenon as a condition that occurs when the body is unable to adapt within the limits of its “reaction norm”, determined by the genotype. Destabilization (especially structural) of the mammalian genome induced by various factors should be considered as an inseparable sign of overstrain of the organism and the formation of stress. Attempts to adapt at the genomic level may lead to changes in the rate and direction of the evolutionary process. It is proposed to differentiate stress taking into account the classification of living organisms and the level of changes being studied.