Andrey Sergeevich Aksenov

Introduction: The environment-nutrition-health triad is particularly important in the Arctic, where traditional diets based on fish, wild birds, and marine mammals may be the primary pathway for the intake of persistent organic pollutants (POPs). In the Russian Federation, systematic biomonitoring of POPs in remote island communities is lacking, which complicates human health risk assessment. Objective: To assess changes in the levels of polychlorinated biphenyls and organochlorine pesticides (OCPs) in the blood serum of residents of the island territories of the Nenets Autonomous Okrug (NAO) between the years 2018 and 2022. Materials and Methods: A cohort of residents of two island communities in the NAO was surveyed in 2018 and 2022. Concentrations of 10 PCB congeners and 17 OCPs were determined using gas chromatography-mass spectrometry. Statistical data analysis was performed using the Mann–Whitney U test, the Wilcoxon signed-rank test, and Spearman’s correlation analysis. Results: The median concentration of ΣPOPs decreased from 526 ng/g lipid in 2018 to 219 ng/g lipid in 2022 (p = 0.001). Residents of Varnek had higher concentrations of the analyzed compounds compared to residents of Bugrino: p,p’-DDE (182 vs. 83 ng/g lipid), PCB-153 (768 vs. 16 ng/g lipid), and PCB-180 (473 vs. below the LOQ). We found a positive correlation between the consumption of Arctic cisco (Coregonus autumnalis) and serum POP levels (r = 0.895, p < 0.05). Relative stability or an increase in HCB levels was observed. Conclusion: A cohort approach is applicable to assessing the dynamics of POP exposure in isolated Arctic communities. The decrease in levels of traditional POPs is consistent with global data, but the increase in HCB concentrations indicates persistent sources of intake. Inter-settlement differences associated with traditional di-ets justify the need for continued systematic biomonitoring in the Russian Arctic.

This study provides the data on the microbial communities associated with brown trout (Salmo trutta L.) at the yolk-sac stage and within the gut of one-year-old individuals reared in a recirculating aquaculture system (RAS) in the Arkhangelsk region. Taxonomic profiling of bacterial communities in both larvae and adult fish was conducted using metabarcoding of the V4 hypervariable region of the 16S rRNA gene. The results indicate that the yolk-sac stage microbiota is predominantly composed of genera Lactobacillus, Cutibacterium, Polynucleobacter, and members of the family Comamonadaceae, whereas the gut microbiota of adult individuals is dominated by Lactobacillus, Pseudomonas, Acetobacter, and Cutibacterium. Alpha diversity indices (Shannon, Simpson, Chao1) revealed moderate abundance and homogeneity of the microbial communities at the early development stage, with a subsequent increase in microbial diversity and heterogeneity in adults. Beta diversity analysis identified overlapping yet largely distinct communities across the different ontogenetic stages. The core set of metabolically and physiologically significant bacteria appears to be primarily shaped by internal succession and dietary interactions, whereas the contribution of environmental water microbiota is limited. These findings on diversity and composition of the bacterial communities in brown trout offer a foundation for development of probiotic and management strategies in aquaculture aimed at enhancing digestive efficiency, immune competence, and post-release survival in natural water bodies.

Background. Studying the diversity of bacteriophages in pristine Arctic ecosystems is of significant interest for determining strategies for finding viruses that can be used as antibacterial agents against multidrug-resistant bacteria. The aim of the study was to describe the structure and characteristics of viromes associated with seabird colonies on the Barents Sea islands as a potential source for virulent bacteriophages that can be used for phage therapy of infectious diseases in humans and animals. Material and methods. The study included metagenomic analysis of soil samples collected in the seabird colonies on Severny Island (Novaya Zemlya archipelago) and Western Northbrook Island (Franz-Josef Land archipelago), as well as isolation and sequencing of Escherichia coli bacteriophage genomes from these samples. Metagenomic sequencing was performed on a DNBSEQ-G400 sequencing platform with a paired-end read length of 150 base pairs. Further analysis included assembling raw reads into contigs using MEGAHIT version 1.2.9, followed by classification using Kraken2 and the RefSeq database of viral sequences. Bacteriophage isolation was achieved through the accumulation method using Escherichia coli flora2c and OO17 cultures. The genomes of the two isolated bacteriophages were sequenced, and their phylogenetic relationships were analyzed using the Parsnp program. Results. The structure of metaviromes is dominated by sequences of Caudoviricetes-class tailed phages, accounting for up to 78.45% of the total number of classified viral sequences. The analysis of metavirome data revealed a significant diversity of Caudoviricetes bacteriophages, including Straboviridae and Shitoviridae families and genera such as Baikalvirus and Phitrevirus . Representatives of these genera can be used in phage therapy. Two virulent Escherichia coli bacteriophages were isolated from ornithogenic soil samples. Based on phylogenomic analysis, one of them represents a known species of the genus Justusliebigvirus , while the second can be classified as a novel species of the genus Kagunavirus . Conclusion. The current study reveals a considerable diversity of virulent bacteriophage species in the microbiomes associated with Arctic seabird colonies, suggesting that there is potential for finding new bacteriophages applicable for phage therapy.

Production of highly porous nanomaterials is an emerging trend that involves the conversion of plant-based polymers, agricultural residues, and forest industry byproducts into value-added products. This process is aligned with the goals of environmental sustainability, efficient use of resources and addressing food security issues through the synthesis of chemical and biological substances. In this study, ultralight (0.031–0.086 g/cm³) macroporous materials derived from biomodified pulps with varied compositions, degrees of conversion, and crystallinity are prepared and analyzed by scanning electron microscopy, low-temperature adsorption–desorption of nitrogen, Fourier-transform infrared spectroscopy, etc. It is shown that these highly porous materials exhibit characteristics consistent with those of cryogel scaffolds, featuring interconnected nanostructure, mechanical stability, porosity of 93.8–97.8%, a specific surface area of 5.53–13.75 m²/g, and swelling ratio of 12.1–24.4 g/g. Therefore, the combination of chemical modification methods and controlled enzymatic hydrolysis makes it possible to vary the parameters of the cryogels, which promotes the formation of porous structures suited for solving specific practical tasks.

Ten samples of Atlantic salmon ( Salmo salar L.) caught in the Mezen River in the Mezensky District of the Arkhangelsk Region were prepared by the methods traditional for this place: cooking, frying, baking and salting. Methods for fish preparation, utensils and auxiliary materials were chosen based on the data of survey of the local population. The study assessed experimentally an effect of four methods of culinary processing on the concentration of six elements in the fish fillet: mercury (Hg), arsenic (As), lead (Pb), cadmium (Cd), zinc (Zn) and copper (Cu). Analysis of the results of the experiment demonstrates changes in all six elements in the Atlantic salmon fillet upon culinary processing irrespective of the chosen method, although each method affected these indicators in different degrees. As a result of the study, it has been established that the cooking process led to a decrease in the level of mercury and arsenic in Atlantic salmon in the highest degree. This method of fish preparation is also preferable for the maximum preservation of essential elements — zinc and copper. With that, arsenic and lead are drawn into the broth during cooking. It has been shown that it is best to salt Atlantic salmon to reduce a concentration of cadmium. Salting also demonstrated a significant reduction in the levels of mercury in the fish fillet. However, salting also reduces the concentration of essential zinc and copper. Frying and baking demonstrated the similar effect on changes in the levels of cadmium and copper. It has been confirmed that fish preparation at a high temperature (frying, baking) facilitates a decrease in the levels of essential zinc and copper.

A promising application of smart materials based on natural polymers is the potential to solve problems related to hemostasis in cases of severe bleeding caused by injury or surgery. This can be a life-threatening situation. Cellulose and its modified derivatives represent one of the most promising sources for creating effective hemostatic systems, as well as for various sensing applications related to disease detection, infection diagnosis, chronic condition monitoring, and blood analysis. The aim of this review was to identify key criteria for the efficiency of cellulose-based gels with hemostatic activity. Experimental studies aimed at evaluating new hemostatic devices were analyzed based on international sources using the PRISMA methodology. A total of 111 publications were identified. Following the identification and screening stages, 20 articles were selected for the final qualitative synthesis. The analyzed publications include experimental studies focused on the development and analysis of highly porous cellulose-based scaffolds in the form of aerogels and cryogels. The type and origin of cellulose, as well as the influence of additional components and synthesis conditions on gel formation, were investigated. Three major groups of key criteria that should be considered when developing new cellulose-based highly porous scaffolds with hemostatic functionality were identified: (I) physicochemical and mechanical properties (pore size distribution, compressive strength, and presence of functional groups); (II) in vitro tests (blood clotting index, red blood cell adhesion rate, hemolysis, cytocompatibility, and antibacterial activity); (III) in vivo hemostatic efficiency (hemostasis time and blood loss) in compliance with the 3Rs policy (replacement, reduction, refinement). The prospects for the development of highly porous cellulose-based scaffolds are not only focused on their hemostatic properties, but also on the development of smart platforms.

The intestinal microbiome of fish at early stages of ontogeny represents a complex and dynamic ecosystem that is critically important for immune system development, physiological resilience, and growth. The yolk-sac stage is of particular significance, as larvae rely exclusively on endogenous nutrient reserves while being colonized by microbes for the first time. During this period, the foundations of microbiota are established, which subsequently influence the development of the digestive system, barrier functions, and pathogen resistance. Recent studies show that microbial communities at this stage are characterized by low alpha diversity and the dominance of Proteobacteria, Firmicutes, and Bacteroidetes. With the transition to exogenous feeding, there is an increase in taxonomic and functional diversity, along with the emergence of probiotic genera (Bacillus, Lactobacillus, Shewanella) that promote enzymatic activity, immune modulation, and increased survival of larvae. This review systematically compiles data from the past 20 years, encompassing both culture-dependent methods and high-throughput sequencing approaches. It has been demonstrated that despite the limitations of culture-based methods, they remain indispensable for isolating probiotic strains. A comparison of methodologies revealed high variability in protocols, complicating the direct comparison of results. The findings underscore the applied significance of studying microbiota for aquaculture during the yolk-sac stage. The management of microbial communities through probiotics, prebiotics, and environmental regulation presents prospects for enhancing the survival, growth, and resilience of fish larvae.

Introduction. Severe bleeding and uncompensated blood loss remain some of the most serious complications associated with trauma and surgical interventions that can threaten life. In recent years, intensive research has been directed toward developing hemostatic materials based on natural and synthetic polymers. Among them, cellulose and its modified derivatives represent one of the most promising sources for creating effective hemostatic systems. The aim of this review was to identify key criteria for the efficiency of cellulose-based gels with hemostatic activity. Methods. Experimental studies aimed at evaluating new hemostatic materials were analyzed based on international sources using the PRISMA methodology. Results. A total of 111 publications were identified. Following the identification and screening stages, 20 articles were selected for the final qualitative synthesis. The analyzed publications include experimental studies focused on the development and analysis of highly porous cellulose-based scaffolds in the form of aerogels and cryogels. The type and origin of cellulose, as well as the influence of additional components and synthesis conditions on gel formation, were investigated. Discussion and Conclusions. Three major groups of key criteria that should be considered when developing new cellulose-based highly porous scaffolds with hemostatic functionality were identified: (I) physicochemical and mechanical properties (pore size distribution, compressive strength, and presence of functional groups); (II) in vitro tests (blood clotting index, red blood cell adhesion rate, hemolysis, cytocompatibility, and antibacterial activity); (III) in vivo hemostatic efficiency (hemostasis time and blood loss) in compliance with the 3Rs policy (replacement, reduction, refinement).

Identification of emerging contaminants in fish species consumed by indigenous peoples remains an important task in the Arctic from the perspective of preserving human chemical safety. This study presents an interlaboratory comparison of the analysis results of polychlorinated biphenyl (PCB) congeners in coregonid fishes, using the Norilo-Pyasinskaya water system on the Taimyr Peninsula as an example, where a large enterprise is located. Two laboratories conducted analyses to quantify PCB levels in the muscle tissue of fish caught at various distances from the suspected contamination source. The Bland–Altman method demonstrated good agreement between the laboratories in the analysis of both the total PCBs and individual congeners 101, 118, 138, and 153. Small differences in results may be due to variations in detector calibration, chromatographic separation, selectivity for specific compounds, or both. Geographical differences in PCB content in coregonid fishes were observed depending on the distance from the suspected pollutant discharge point. Meanwhile, other fish parameters, such as age, weight, and lipid content, had little effect on PCB levels. The use of Standard Reference Materials (SRM) and control materials in laboratories is recommended, as they help confirm analytical results and ensure these procedures remain controlled.

Birds, fish, and marine mammals consumed by indigenous people are included in Arctic biomonitoring. However, there are still many gaps in the data on the microbiota associated with these animals. In the current study, we used high-throughput 16S rRNA gene sequencing to explore the bacterial diversity and composition in the intestines of willow ptarmigans, greater white-fronted geese, and taiga bean geese, which are widely consumed by indigenous people in the Arctic. For the first time, meta-taxonomic data have been obtained on the lungs of wild resident and migratory birds of the Russian North. The potentially pathogenic bacterial genera Helicobacter and Olsenella were found in the intestinal microbiomes of three bird species and in the lungs of willow ptarmigan. Bacteria of the genus Staphylococcus were individually identified in the intestines of willow ptarmigan, Campylobacter sp. in the intestines of taiga bean goose, and Sutterella sp. in the intestines of greater white-fronted goose as potential pathogens. The primary findings will be used to propose a next-generation sequencing scheme for monitoring both chemical and biological contaminants in the Arctic in line with One Health approach.