Search Results (152)

The naviculoid genus Luticola exhibits a high degree of morphological convergence, complicating species delimitation when based solely on traditional morphometrics. Here, we describe Luticola edaphica sp. nov., a new species isolated from the forest soils of Mount Sestra (Primorsky Territory, Russian Far East) using an integrative taxonomic approach (phylogenetic, morphological, ultrastructural, and life cycle data). Molecular phylogenetic analysis, based on the chloroplast rbcL gene, placed the new strain within the Luticola clade, showing the closest affinity to L. tenera. However, L. edaphica is distinguished from similar Luticola species by a unique combination of morphological traits (structure of the valvocopula, maximal valve length and width, position and number of striae in 10 µm, central area, and distal raphe ends). A comprehensive study of its life cycle revealed that L. edaphica is homothallic and capable of both cis- and trans-anisogamy, with the latter being reported for the genus for the first time. Full article

The distribution and genetic diversity of economically significant pathogens, including porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2), porcine circovirus type 3 (PCV3), and porcine parvovirus 1 (PPV1), across extensive Russian territory within wild boars that serve as reservoirs remain poorly characterized. This study aimed to conduct a molecular epidemiological survey of these viruses in wild boar populations. The samples of 476 wild boars, collected across Russia between 2021 and 2025, were tested by PCR for the detection of viral genomes. While PRRSV was not detected, we found high detection rates for PCV2 (34.9%), PCV3 (35.5%), and PPV1 (25.4%). For PCV2, the co-circulation of two genotypes, PCV2b (5/53) and PCV2d (48/53), was observed. All 29 PCV3 sequences belonged to the PCV3a genotype. For PPV1, the presence of the PPV1a, PPV1b, and PPV1d genotype, as well as unclassified isolates, was shown. Co-infection of different viruses was detected: PCV2/PCV3 (16.0%), PCV2/PPV1 (6.9%), PCV2/PCV3/PPV1 (6.9%), and PCV3/PPV1 (4.4%). This is the first comprehensive study that demonstrates the wide dissemination and genetic diversity of PCV2, PCV3, and PPV1 within the wild boar population in Russia and highlights their role as a potential reservoir in viral evolution and spread. Full article

Human adenoviruses (HAdVs) are globally distributed pathogens capable of causing a wide range of clinical manifestations, particularly acute respiratory infections. However, their genomic diversity remains insufficiently characterized, with substantial geographic gaps in available sequence data, including for Russia, where only a few complete genomes have been deposited prior to this work. In this study, we analyzed more than 1200 PCR-positive respiratory specimens collected from hospitalized patients within routine surveillance projects and the Global Influenza Hospital Surveillance Network (GIHSN) across plenty of Russian regions during 2023–2024. Virus isolation followed by next-generation sequencing yielded 128 complete HAdV genomes representing species B, C, and D. The dataset included 27 B3, 9 B7, 44 B55, 12 C1, 16 C2, 4 C5, 7 C89, 5 C108, and one D109 genome, as well as three unassigned recombinant viruses with p89h5f5, p5h6f6 and p5h57f6 genomic structures (p, penton base; h, hexon; f, fiber). Phylogenetic analyses of whole genomes and capsid genes revealed extensive variability in immunogenic regions, particularly in species C, and identified clusters within B3 viruses. Notably, HAdV-D109 was identified in Russia, marking only the second reported detection of this genotype worldwide. Together, these findings substantially expand the currently available genomic landscape of HAdVs, highlighting the circulation of diverse and recombinant strains in Russia. Full article

Highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.4b has recently emerged as a major threat to wildlife, agriculture, and public health due to its expanding host range and the increasing frequency of spillover into mammals. In July–August 2023, the mass death of over 3500 northern fur seals (Callorhinus ursinus) and at least one Steller sea lion (Eumetopias jubatus) was recorded on Tyuleniy Island in the Sea of Okhotsk, Russia. Two HPAI A(H5N1) viruses were isolated from fur seal carcasses and designated A/Northern_fur_seal/Russia_Tyuleniy/74/2023 and A/Northern_fur_seal/Russia_Tyuleniy/75/2023. Both viruses exhibited high pathogenicity in chickens (IVPI 2.7–3.0) and mice (MLD₅₀ 1.9–2.5 log₁₀EID₅₀/mL), with distinct differences in disease progression, histopathology, and organ tropism. Experimental infection of mice revealed that strain A/74/2023 induced more severe pulmonary and neurological lesions than A/75/2023. Whole-genome sequencing and phylogenetic analysis demonstrated close relatedness to HPAI H5N1 strains circulating in the Russian Far East and Japan from 2022 to 2023, with several mutations associated with mammalian adaptation, including NP-N319K and, in one isolate, PB2-E627K. According to our findings, northern fur seals (Callorhinus ursinus) on Tyuleniy Island acted as spillover hosts for the highly pathogenic avian influenza (HPAI) H5N1 virus of clade 2.3.4.4b. Furthermore, the high population density of fur seals and the extensive mortality observed during the outbreak highlight these animals’ potential role as another vessel for the evolution of avian influenza viruses. This study represents the first documented case of HPAI H5N1 in pinnipeds in the North Pacific region and supports previous reports indicating that pinnipeds, including northern fur seals, are highly susceptible to HPAI H5N1 clade 2.3.4.4b viruses. Full article

Despite extensive research into green microalgae belonging to the genus Chloroidium, their species diversity and biotechnological potential remain poorly characterized. The strain VKM Al-418, the subject of this study, was isolated from the soil of Duvannyi Yar (Russian Federation). The independent species status of this strain is supported by distinct morphological characteristics, robust phylogenetic placement based on the 18S-ITS1-5.8S-ITS2 fragment, and unique features in the secondary structures of both ITS1 and ITS2, including one compensatory base change (CBC) in the highly conserved helix III of ITS2. Additionally, the species delimitation was also confirmed using five independent algorithmic approaches analyzing four different DNA barcodes. The concatenated ITS1-5.8S-ITS2 fragment is more reliable for species discrimination than the individual ITS1 or ITS2 barcodes. Of the species delimitation methods evaluated, ASAP (Assemble Species by Automatic Partitioning) and GMYC (Generalized Mixed Yule Coalescent) performed best in distinguishing Chloroidium species across multiple barcode regions in our analysis. The fatty acid profile of strain VKM Al-418 was analyzed at 9 °C, 22 °C, and 27 °C and exhibited high plasticity in response to temperature, indicative of an adaptive strategy to its harsh environment. Using this integrative taxonomic approach, we describe Chloroidium pseudoellipsoideum sp. nov., a new species with a distinct phylogenetic positioning and promising biotechnological properties. Full article

Multicomponent pollution of groundwater with nitrates and sulfates is a common issue associated with mining and ore-processing operations. This work presents the first large-scale comparative study of groundwater microbial communities from six geographically distant sites in the Russian Federation with varying levels of nitrate and sulfate pollution. Based on high-throughput 16S rRNA sequencing data and hydrochemical analysis, a statistically significant influence of the pollution type on the structural and functional diversity of the microbiome was established. Nitrates act as a stimulating factor, increasing alpha-diversity, while sulfates have an inhibitory effect. Principal component and correlation analysis revealed spatial grouping of samples according to the predominant pollution type. Microbiome representatives common to all sites under unpolluted conditions were identified: Bacteroides, Iamia, and Paenibacillus; and under high pollution levels: Acidovorax, Pseudomonas, Sphingomonas, Acinetobacter, and Limnohabitans. Based on the obtained data, it is concluded that representatives of these genera are the most promising and universal for isolation and use in bioremediation. Full article

The European part of Russia has been characterized by a remarkably low documented diversity of entomopathogenic fungi, particularly when compared to the high species richness recorded in the Russian Far East. This pattern has persisted through decades of primarily morphology-based studies, which require critical reassessment using modern molecular methods. Here, we introduce a new species, Cordyceps biarmica, described from its asexual stage collected in the taiga of Arkhangelsk Oblast, representing a notable addition to the known diversity of the genus Cordyceps in the region. The fungus was isolated from a poorly preserved lepidopteran cocoon with pulvinate, unbranched conidiomata. Morphological features of its pure culture revealed an Isaria-like asexual morph characterized by solitary or verticillate phialides on a subspherical to subcylindrical base, bearing conidia in imbricate chains twisted in spirals. Multilocus phylogenetic analysis of a five-locus dataset (ITS, nrLSU, rpb1, rpb2, and tef1-α) was conducted using Maximum Likelihood and Bayesian Inference. The isolate was robustly placed within Cordyceps s.s., forming a distinct monophyletic lineage separate from other closely related well-supported taxa, including Cordyceps cateniannulata, C. exasperata, C. locastrae, C. polyarthra, C. sandindaengensis, and C. spegazzinii. Full article

Between 2019 and 2023, 163 cases of subgenotype VII.1.1 Newcastle disease virus infection were registered in backyard poultry in the Russian Federation within the framework of epizootiological monitoring. Subgenotype VII.1.1 Newcastle disease virus was reported in a total of 18 different subjects of the Russian Federation. Most of the Newcastle disease outbreaks caused by the viruses of this subgenotype occurred in the autumn and winter period (60%). Further tests allowed for the determination of complete F and HN gene nucleotide sequences for 40 isolates. The results were used to perform the Bayesian analysis of F gene sequences with BEAST v.1.10.4 software. The obtained nucleotide substitution accumulation rates were practically non-dependent on the selected nucleotide substitution model and varied appreciably depending on the applied molecular clock model (0.0018 and 0.002 site-1year-1). The conducted study established that the formation of the ‘Russian’ NDV isolates of subgenotype VII.1.1 followed several stages. In the early 2000s, ancestral viruses belonging to subgenotype VII-d were detected in the Middle East and Eastern Europe. From these, through intermediate forms identified in Iraq around 2007–2008, a group designated as subgenotype VII-L emerged. This group gave rise to two sister clades: the Iranian subgenotype VII-L and the cluster of isolates from Russia and Poland, whose immediate common ancestor likely existed around 2015–2016, probably in Asia. Full article

The species diversity of the recently described genus Drouetiella (Oculatellaceae, Cyanobacteriota), including thin filamentous cyanobacteria, has been rapidly increasing due to the subsequent discovery of new-to-science species in the last several years. This study focuses on one more strain that was isolated from a small lake on the Chukotka Peninsula in the Russian Arctic and tested by an integrative approach. In the result of molecular phylogenetic analysis of the 16S rRNA gene and the 16S–23S ITS rRNA region, this strain was found in a separate clade in the genus Drouetiella. The strain is characterized by unique secondary structures of conserved regions D1–D1′, Box–B, V2, and V3 helices of the 16–23S ITS rRNA. Morphologically, the tested strain was distinct from other Drouetiella species by long cells in mature trichomes, absence of false branching, and hormogonia. Drouetiella elegans occurred in the plankton of a small lake and shared ecological similarities with some aquatic strains of Drouetiella lurida. We provide a taxonomic description of a new species, Drouetiella elegans sp. nov. Full article

Hyalomma ticks are known for their ability to transmit a wide range of pathogens, posing a significant threat to both human and animal health. The viral communities associated with Hyalomma asiaticum ticks in Kazakhstan remain largely unexplored. Using high-throughput sequencing on the Ion Torrent platform, nine RNA viruses belonging to seven families were identified. These viruses were associated with H. asiaticum ticks collected in 2024 in southern Kazakhstan. The detected viruses—including Bole tick virus 1 (Phenuiviridae), Bole tick virus 3 (Chuviridae), Bole tick virus 4 (Flaviviridae), Hubei toti-like virus 24 (Totiviridae), Kashgar totiv tick virus 1 (Totiviridae), Lonestar tick totivirus (Totiviridae), Qingyuan parti tick virus 1 (Partitiviridae), and Taishun tick virus (Rhabdoviridae)—had previously been reported only in China. This study provides the first documented evidence of the presence of RNA viruses previously unreported in Kazakhstan within H. asiaticum tick populations. A newly isolated Kazakhstan strain of Wad Medani virus (Sedoreoviridae), identified from H. asiaticum, shares genetic similarities with Russian strains, suggesting a common epidemiological landscape across Central Eurasia. The detection of novel RNA viruses in Kazakhstan highlights the need for ongoing surveillance, as their impact on human and animal health remains insufficiently understood. Full article

Human parainfluenza viruses 3 (hPIV3) are important pathogens, responsible for acute respiratory tract diseases, especially in young children. Information on hPIV3 circulation and their diversity pattern in Russia is limited. The aim of this study was to perform a molecular and genetic characterization of hPIV3 circulating in Saint Petersburg, Russia. From October 2017 to September 2023, 14,704 swabs were screened using real-time reverse transcription-PCR. A phylogenetic analysis of the complete hemagglutinin–neuraminidase (HN) gene was performed. Out of 1334 positive hPIV cases, hPIV3 was the most common subtype. Phylogenetic analysis of the studied and previously published HN sequences revealed four distinct genetic clusters, A, B, C, and D, with Cluster D being first delineated in this study. In addition, two newly subdivided genetic lineages, C5a and C5b, were documented. Phylogenetic analysis revealed that the analyzed Russian strains grouped into Cluster C and D; further subclusters C5a, C5b, C3b, C3e, and C3a. While three strains were classified within cluster D, the majority of isolates fell within subcluster C3a, followed by C5b. Taken together, these findings demonstrate the co-circulation of hPIV3 strains during the study period. This is the first study that describes the genetic and molecular aspects of hPIV3 circulating in Russia. Moreover, our results provide an up-to-date hPIV3 phylogenetic analysis. Full article

Background: Vancomycin-resistant Enterococcus faecium (VREfm), particularly vanA-positive strains, represents a growing threat in hospital settings worldwide. These bacteria are able to survive under severe environmental conditions, including high temperatures and saline concentrations. High genome plasticity and advanced ability of inheriting antimicrobial resistance determinants defined the success of E. faecium as a hospital pathogen. Methods: This study presents the whole genomic characterization of vanA-positive VREfm isolates, analyzing 10 clinical isolates collected from three tertiary care hospitals in Moscow, Russia. Several typing approaches, including two MLST schemes and cgMLST profiles, were used to elucidate the relationship between the isolates. Phylogenetic analysis placed the isolates in context with global VREfm populations, demonstrating both local clonal expansion and possible international connections. Phenotypic and genomic antimicrobial resistance profiles were obtained, as well as data regarding the repertoire of virulence factors and plasmid content. Results: Whole genome sequencing revealed that all isolates belonged to the clinically significant CC17 lineage, specifically sequence types ST80 and ST552. Notably, two isolates possessed truncated Tn1546-type transposons lacking vanY and vanZ genes, representing a potentially emerging variant of the vanA operon in Russian clinical settings. A plasmid carrying a truncated vanA operon was reconstructed using long-read sequencing. Conclusions: The study highlights the utility of genomic investigation for tracking resistance mechanisms and strain dissemination, providing crucial baseline data for epidemiological surveillance of infections caused by VREfm in Russia. These findings emphasize the need for continued genomic monitoring to understand the evolution and spread of antimicrobial resistance in clinically important enterococcal lineages. Full article

Studies of HIV-1 molecular epidemiology describe significant differences in HIV infection spread across geographical areas. We examined 80 HIV-1 samples from the Jewish Autonomous Region of Russia in 2024. HIV-1 genome sequences for 12 samples revealed a novel HIV-1 called CRF173_63A6. HIV-1 CRF173_63A6 was found to have arisen through recombination between a specific Russian A6 subtype and the recombinant virus CRF63_02A6, which is responsible for the PWID-associated HIV outbreak in the Siberian region of Russia. Phylogenetic analysis of pol sequences previously deposited in Genbank showed that the CRF173_63A6 samples we described are grouped into a common phylogenetic cluster that includes 54 HIV-1 samples isolated in the JAR and other areas of the Russian Far East, indicating a wide distribution of this virus genovariant. This study once again proves the significant contribution of the key PWID group not only to the development of local Russian HIV epidemics, but also to the change in the characteristics of the circulating virus population. Full article

The recent discovery of the Yezo virus (YEZV) in Japan and China has raised particular concern due to its potential to cause human diseases ranging from mild febrile illnesses to severe neurological disorders. We report, for the first time, the detection of five YEZV isolates in I. persulcatus ticks from three regions of Russia. The analysis was performed using 5318 ticks of two Ixodes genus collected in 2024 from 23 regions of Russia. The minimum infection rate of YEZV in Russia among I. persulcatus ticks was 0.12% (95% CI: 0.05–0.28). The westernmost and northernmost YEZV detection points have been recorded. YEZV isolates circulating in Russia are genetically diverse. Protein domains of Russian YEZV isolates’ genomes were characterized using HMMER, AlphaFold 3, and InterProScan. The YEZV nucleoprotein (N) of Russian isolates has a racket-shaped structure with “head” and “stalk” domains similar to those of Orthonairovirus haemorrhagiae. The Lys261–Arg261 substitution in the YEZV N Chita 2024-1 isolate occurs in the α11 structure in the region of interaction with viral RNA. Our results show that the distribution area of YEZV is much wider than previously known, provide new data on complete YEZV genomes, extend our structural insight into YEZV N, and suggest a potential target for antiviral drug development to treat YEZV infection. Full article

Porcine parvovirus 5 (PPV5) is a novel virus frequently detected in pigs worldwide. However, its identification and prevalence in domestic pigs in Russia have not been described. In this study, retrospectively, 984 serum samples collected between 2020 and 2023 were tested by qPCR. All samples were obtained from 20 pig farms located in 10 regions of Russia. PPV5 circulation was confirmed in 11 pig farms with the overall detection rate at 8.9%. The highest detection rate was estimated in the farms of the Belgorod Region (17.1%), followed by the Sverdlovsk Region (15.9%), the Republic of Buryatia (14.7%), and the Moscow Region (14.0%). It has been confirmed that PPV5 has been circulating in the swine population since at least 2021. The phylogenetic analysis revealed a high nucleotide identity of Russian isolates with strains from the USA, Colombia, and China. The Moscow-4060 strain was isolated in primary porcine testicular cells (PPTCs), and its continuous replication was confirmed by qPCR. During microscopy, cytoplasmic vacuolization, pyknosis, and other alterations were observed. The results demonstrate the evidence of PPV5 circulation in domestic pigs in Russia and the first isolation of the virus ever described. These findings serve as a first step for studying PPV5 in vivo. Full article