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In light of the morphological and molecular data for cyclocoelids observed from the air sacs of Mareca strepera (Linnaeus) (Anatidae, Anseriformes) caught in the southern region of the Russian Far East, we suggest new insights into the systematics of the family Cyclocoelidae. A comparative morphological and phylogenetic analyzes revealed that new cyclocoelids represented the new genus and species Paracyclocoelum lobatum. Based on the 28S rRNA gene fragment we showed the significant genetic divergence of P. lobatum from the type species of the type genus for the family, Cyclocoelum mutabile (Zeder, 1800) Brandes, 1892 and along with the confusing morphological similarity by the prepharyngeal position of the genital pore it most likely indicate homologous development of the reproductive system of Paracyclocoelum and Cyclocoelum. Here, we provide a new dichotomous key for five cyclocoelid genera from the subfamily Cyclocoelinae including Paracyclocoelum n. g. The new genus Paracyclocoelum had sister relationship to the cyclocoelin genus Circumvitellatrema. Based on the polyphyletic interrelationships of Cyclocoelum and Circumvitellatrema the Cyclocoelinae were assigned with the status sensu lato., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Due to the developing resistance and intolerance to antiretroviral drugs, there is an urgent demand for alternative agents that can suppress the viral load in people living with human immunodeficiency virus (HIV). Recently, there has been increased interest in agents of marine origin such as, in particular, fucoidans to suppress HIV replication. In the present study, the anti-HIV-1 activity of fucoidans from the brown algae Alaria marginata , Alaria ochotensis , Laminaria longipes , Saccharina cichorioides , Saccharina gurianovae , and Tauya basicrassa was studied in vitro. The studied compounds were found to be able to inhibit HIV-1 replication at different stages of the virus life cycle. Herewith, all fucoidans exhibited significant antiviral activity by affecting the early stages of the virus-cell interaction. The fucoidan from Saccharina cichorioides showed the highest virus-inhibitory activity by blocking the virus' attachment to and entry into the host's cell, with a selectivity index (SI) > 160.

All bacterial strains studied retained the viability and ability to form both mono- and polycultural biofilms under conditions of long-term culturing in artificial seawater at 6°C and without addition of nutrients. Bacillus sp. and Pseudomonas japonica presumably stimulated the growth and reproduction of the pathogenic bacteria Listeria monocytogenes and Yersinia pseudotuberculosis. Preserved cell viability in a monoculture biofilm for a long period without adding a food source can indicate allolysis. At the same time, in a polycultural biofilm, the metabolites secreted by saprotrophic strains can stimulate the growth of L. monocytogenes and Y. pseudotuberculosis., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature.)

Here, we continued the investigation of anti-HSV-1 activity and neuroprotective potential of 14 polyphenolic compounds isolated from Maackia amurensis heartwood. We determined the absolute configurations of asymmetric centers in scirpusin A ( 13 ) and maackiazin ( 10 ) as 7 R ,8 R and 1″ S ,2″ S , respectively. We showed that dimeric stilbens maackin ( 9 ) and scirpusin A ( 13 ) possessed the highest anti-HSV-1 activity among polyphenols 1 - 14 . We also studied the effect of polyphenols 9 and 13 on the early stages of HSV-1 infection. Direct interaction with the virus (virucidal activity) was the main mechanism of the antiviral activity of these compounds. The neuroprotective potential of polyphenolic compounds from M. amurensis was studied using models of 6-hydroxydopamine (6-OHDA)-and paraquat (PQ)-induced neurotoxicity. A dimeric stilbene scirpusin A ( 13 ) and a flavonoid liquiritigenin ( 6 ) were shown to be the most active compounds among the tested polyphenols. These compounds significantly increased the viability of 6-OHDA-and PQ-treated Neuro-2a cells, elevated mitochondrial membrane potential and reduced the intracellular ROS level. We also found that scirpusin A ( 13 ), liquiritigenin ( 6 ) and retusin ( 3 ) considerably increased the percentage of live Neuro-2a cells and decreased the number of early apoptotic cells. Scirpusin A ( 13 ) was the most promising compound possessing both anti-HSV-1 activity and neuroprotective potential.

Wild boars have a worldwide distribution and also have major economic, veterinary, and medical importance. Due to a small amount of data on the parasitic fauna of wild boars in the Russian Far East, especially in Prymorye territory, a post-mortem parasitic examination of 20 wild boars was provided. The general prevalence was 25%, and a total of six helminth species, including one larva stage, were found. The most prevalent helminth species were Gnathostoma doloresi (25%) and Metastrongylus elongatus (20%). Followed by Trichuris suis and Ascaris suum (15%). The lowest prevalence was registered for Cysticercus tenuicollis (the larvae stage of T. hydatigena ). Parasites were found in each region, with the highest prevalence registered in the Chuguevskii region. Totally 100% of adult boars were positive for helminth infections, instead of 60% of young specimens. Some helminthes found ( G. doloresi, T. suis, A. suum ) have zoonotic potential and can be involved in the circulation of human parasitic diseases, especially in rural areas. Further research work on parasitic infections in wild boars in Prymorye is necessary due to the high prevalence of helminthes in wild boars., Competing Interests: Authors declare that they are no any conflict of interests. They also confirm that the MS was not published elsewhere., (© 2024 The Authors.)

We studied the ability of the polyphenolic complex from Maackia amurensis, the active substance of Maksar, to inhibit the cytopathogenic effect induced by the SARS-CoV-2 and to reduce the concentration of viral RNA in infected Vero E6 cells. Polyphenolic complex showed significant anti-SARS-CoV-2 activity and effectively inhibited viral replication by direct action on viral particles and the early stage of viral infection., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature.)

Adult individuals of Echinochasmus pseudobeleocephalus n. sp. were obtained during an experimental study on trematodes' life cycle. An analysis of the morphometric characteristics of the developmental stages and involvement of first intermediate hosts, snails of the genus Boreoelona , in their life cycle, revealed the identity of the obtained trematodes to the European species Echinochasmus beleocephalus previously discovered in the south of the Russian Far East. However, an analysis of molecular data, in particular sequences of the 28S rRNA gene, showed that the Far Eastern trematodes examined do not belong to European E. beleocephalus despite their morphological similarities. An analysis of phylogenetic relationships within the family Echinochasmidae supported the status of E. pseudobeleocephalus n. sp. as an independent species. Our new data confirmed that the individuals attributed to Echinochasmus can be subdivided into two groups on the basis of the number of head-collar spines and the tail length in cercariae on an intergeneric level.

Dictyocaulus xanthopygus sp. nov. (Nematoda: Trichostrongyloidea) was isolated from the lungs of the Manchurian wapiti in Primorsky kray, Russia. The newly described species exhibits morphological characteristics of Dictyocaulus but is distinct from congeneric species based on morphological (lengths of body and esophagus, distances from the anterior end to nerve ring and to excretory pore, the thickness of the buccal capsule, etc.) and molecular features. High levels of genetic divergence as well as Bayesian phylogenetic analyses based on 18S rRNA nuclear and cox1 mitochondrial genes supported the independence of Dictyocaulus xanthopygus sp. nov. Secondary structures of helix 39 of 18S rRNA were identical, while ES9 adjacent to the helix has a unique conformation for newly described worms. Energy-efficient conformational rearrangements of rRNA secondary structures can be applicable in studies on the pathogenesis, epidemiology, taxonomy and evolutionary biology of parasites. Additionally, bracketed dichotomous keys to six valid species of Dictyocaulus were prepared., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Nanoparticles formation is one of the ways to modulate the physicochemical properties and enhance the activity of original polysaccharides. For this purpose, based on the polysaccharide of red algae, κ-carrageenan (κ-CRG), it polyelectrolyte complex (PEC), with chitosan, were obtained. The complex formation was confirmed by ultracentrifugation in a Percoll gradient, with dynamic light scattering. According to electron microscopy and DLS, PEC is dense spherical particles with sizes in the range of 150-250 nm. A decrease in the polydispersity of the initial CRG was detected after the PEC formation. Simultaneous exposure of Vero cells with the studied compounds and herpes simplex virus type 1 (HSV-1) showed that the PEC exhibited significant antiviral activity, effectively inhibiting the early stages of virus-cell interaction. A two-fold increase in the antiherpetic activity (selective index) of PEC compared to κ-CRG was shown, which may be due to a change in the physicochemical characteristics of κ-CRG in PEC.

In this study, we isolated a new isoflavanostilbene maackiapicevestitol ( 1 ) as a mixture of two stable conformers 1a and 1b as well as five previously known dimeric and monomeric stilbens: piceatannol ( 2 ), maackin ( 3 ), scirpusin A ( 4 ), maackiasine ( 5 ), and maackolin ( 6 ) from M. amurensis heartwood, using column chromatography on polyamide, silicagel, and C-18. The structures of these compounds were elucidated by NMR, HR-MS, and CD techniques. Maksar ® obtained from M. amurensis heartwood and polyphenolics 1 - 6 possessed moderate anti-HSV-1 activity in cytopathic effect (CPE) inhibition and RT-PCR assays. A model of PQ-induced neurotoxicity was used to study the neuroprotective potential of polyphenolic compounds from M. amurensis . Maksar ® showed the highest neuroprotective activity and increased cell viability by 18% at a concentration of 10 μg/mL. Maackolin ( 6 ) also effectively increased the viability of PQ-treated Neuro-2a cells and the value of mitochondrial membrane potential at concentrations up to 10 μΜ. Maksar ® and compounds 1 - 6 possessed higher FRAP and DPPH-scavenging effects than quercetin. However, only compounds 1 and 4 at concentrations of 10 μM as well as Maksar ® (10 μg/mL) statistically significantly reduced the level of intracellular ROS in PQ-treated Neuro-2a cells.

Worldwide production and use of the polymers has led to intensive environmental pollution with micro- and nanoplastics (MP and NP). Accumulating in ecosystems, MP are transmitted through food chains and enter the human body. The associated health risks are of grave concern and require assessment. The main entry gate for MP/NP supplied with food is the gastrointestinal tract (GIT). Despite the well-established concept of MP/NP toxicity, information about their actual effects on the GIT is contradictory. The aim of the research was to establish the nature and mechanisms of NPs and MPs action on the gastrointestinal mucosa and intestinal microbiome, basing on the literature data. Material and methods . The review was compiled after selecting of 90 documents from major databases including Web of Science, PubMed, Scopus, Elsevier, Springer and Google Scholar (up to March 2023). Results . In animal studies and in vitro models, it was shown that MP/NP affect mucus secretion, its rheological characteristics, and can cause an increase in the permeability of tight junctions of epithelial cells by reducing the expression of zonula occludens protein 1 (ZO-1), occludin and claudin-1, which promotes the penetration of MP through the intestinal wall. Various adsorption layers (coronas) formed on the surface of MPs both abiotically and during transit through the GIT can lead to both increased and reduced toxicity of MPs. Biofilms formed on MP/NP surface create favorable conditions for the activity of pathogenic bacteria and horizontal gene exchange between the components of the biofilm and the intestinal microbiome. Animal experiments have shown an unfavorable effect of MP/NP on the intestinal microbiota and its key metabolites, contributing to the development of dysbiosis. Conclusion . Most data on the effect of MP on the GIT have been obtained using a model object - polystyrene microspheres, which are rarely found in practice. A frequent limitation of the in vitro studies is the discrepancy between used doses (concentrations) of MP and those that may occur when MP are consumed with food. Data on the potential impact of MP/NP on the GIT protective barrier and intestinal microbiota obtained under various experimental conditions are contradictory. Thus, evidence of the impact of MP/NP on the GIT and intestinal microbiota of humans needs further confirmation, which will allow us to move on to the development of a set of measures that can reduce the risks of MP exposure to human health., Competing Interests: The authors have no conflict of interest to declare., (Copyright© GEOTAR-Media Publishing Group.)

The creation of specialized food systems capable of correcting body weight and influencing lipid metabolism is an urgent task at the present stage. The main way to create such food systems is to modify product profiles (lipid, protein, carbohydrate, mineral, vitamin, etc.). The aim of the study was to obtain and characterize a new food source of an organic form of chromium for the prevention of hyperlipidemia and obesity in the form of a complex with peptide fractions of fermentolysate proteins of the Mactra chinensis bivalve mollusk from the Far Eastern region. Material and methods . Soft food parts of the Mactra chinensis bivalve mollusk from the Far Eastern region (the motor muscle and mantle) were used as objects of research. Mollusk specimens were collected in the Amur Bay in June - September 2022. Biotechnological modification of soft tissue proteins was carried out using alkaline protease protozyme B with the following parameters: the duration of the process - 12 and 24 hours, pH - 7.0-7.2, temperature 55 °C. The fractional composition of proteins and peptides was determined by medium pressure gel permeation chromatography, the molecular weight (MW) of proteins and peptides was calculated using MW markers by comparing retention volumes. Extraction of free amino acids was carried out with 70% ethanol for 24 hours at a temperature of 20 °C, the composition and quantitative content of amino acids were determined by HPLC. The complexation reaction was carried out by adding to the fermentolysate with stirring a 10% aqueous solution of CrCl3×6H2O in a mass ratio of 6.25 × nitrogen in the liquid fraction : chromium (III) chloride = 20:1. Process conditions: temperature 20-25 °C, time 60 min, pH 7.0-7.1. The chromium content was determined by the atomic absorption method using spectrophotometer. Results . The content of low-molecular fractions increased more significantly over time in the mantle fermentolysate. The content of the high-molecular fraction of peptides weighing more than 160 kDa was minimal for both the muscle and the mantle and didn't exceed 1.1%. Low-molecular fractions weighing no more than 18 kDa in the 24-hour fermentolysate accounted for 79.6% for the muscle and 86.9% for the mantle. The obtained fermentolysates were characterized by a high content of the biologically active amino acid taurine - 25.9% (muscle) and 30.05% (mantle) of the total amino acid content. The high content of such essential amino acids as glycine, alanine, leucine, lysine, and the conditionally essential amino acid arginine was also determined. The obtained fermentolysates of soft tissue proteins of the Mactra chinensis were characterized by a fairly balanced amino acid composition. It has been experimentally established that more than 84% of the total chromium content in muscle fermentolysate and 80.9% in mantle fermentolysate was associated with peptide fractions with molecular weights from 24 to 1.4 kDa, and the highest specific chromium content - 1.67 mg/g protein (muscle) and 1.58 mg/g protein (mantle) was determined in the interval fractions with molecular weights of 18.0-12.5 kDa. The minimum specific content of the trace element was established for high-molecular fractions of 160-67 kDa and low-molecular fraction weighing less than 1.4 kDa. Conclusion . Biotechnological modification of soft tissue proteins of the Mactra chinensis bivalve mollusk from the Far Eastern region made it possible to obtain a balanced amino acid composition fermentolysate with a high content of the free biologically active amino acid taurine. Fortification of the obtained fermentolysate with chromium demonstrated high efficiency of its binding to the amino acid and peptide matrices of the protein hydrolysate. The chromium complex with fermentolysate of proteins of the Mactra chinensis bivalve mollusk can be used as a food source of chromium and taurine, including as a functional ingredient in special food systems for the prevention of hyperlipidemia and obesity., Competing Interests: The authors declare no conflict of interest., (Copyright© GEOTAR-Media Publishing Group.)

Herpes simplex virus (HSV) infections, the incidence of which is still widespread throughout the world, are actualizing the search and development of new, more effective antiherpetic drugs. The development of multifunctional drug delivery systems, including liposome-based ones, has become a relevant and attractive concept in nanotechnology. The ability of complexes of κ- and Σ-carrageenans (CRGs)-sulfated polysaccharides of red algae, with echinochrome A (Ech), as well as the liposomal form of the Σ-CRG/Ech complex-to inhibit different stages of HSV-1 infection in Vero cells was studied. By quantum chemical calculations, it was shown that CRG forms stable complexes with Ech. We have shown that complexes of κ-CRG/Ech and Σ-CRG/Ech exhibit highest virucidal activity with a selectivity index (SI) of 270 and 350, respectively, and inhibition of virus-cell interaction (SI of 83 and 32, respectively). The liposomal form of the Σ-CRG/Ech complex after virus adsorption and penetration to cells effectively reduced the HSV-1 plaque formation. The virus-inhibiting activity of the liposomal form of the Σ-CRG/Ech complex was three times higher than that of the Σ-CRG/Ech complex itself. Obtaining CRGs/Ech complexes and their liposomal forms can become the basis of a successful strategy for the development of promising antiherpetic drugs.

This study identified helminthic species among wild boars ( Sus scrofa ) in Primorsky Krai, Russia. In total, 66 fecal samples were taken from wild boars and examined using the floatation-sedimentation method to identify helminths eggs and protozoan cysts. Age and sex were estimated for each host animal investigated. The helminthic fauna of the wild boars examined involved six parasite genera, but 4 are helminths and 2 are protozoans: the nematodes Metastrongylus spp ., Trichuris suis , Capillaria sp . and Ascaris suum ; and the protozoan parasites Eimeria sp. and Cystoisospora suis . The most prevalent parasite was Metastrongylus spp. (13.6 %) followed by Trichuris suis (7.6 %). The other parasites found were Eimeria sp. (3 %), Ascaris suum (3 %), Capillaria sp. (1.5 %) and Cystoisospora suis (1.5 %). Not found positive correlation between the host's age and sex and the parasite prevalence. This was the first detailed study on helminths infections among wild boars in Primorsky Krai., Competing Interests: Conflict of Interest Conflict of Interest Statement: The authors declare that they did not have any conflict of interest in conducting this study. Moreover, the authors do not have any potential conflict of interest pertaining to this submission to Helminthologia., (© 2022 YU. A. Belov, T. V.Tabakaeva, D. V. Pankratov, E. M. Shchelkanov, A. L. Surovyi, I. A. Popov, A. V. Tabakaev, L. V. Zheleznova, I. V. Galkina, M. YU. Shchelkanov, published by Sciendo.)

Flukes from the genus Paragonimus Braun, 1899 are medically important foodborne trematodes predominantly occurring throughout Asian countries. Providing molecular genetic characteristics based on ITS2 and partial 28 S rDNA of the paragonimids from the Russian Far East, Northeast, South, and Southeast Asian countries, we performed a partial reappraisal of Paragonimus westermani species complex. Members of this complex are genetically distinct worms with different divergence times and explosive expansion during Miocene-Pliocene epochs. We confirm the taxonomic status as valid species for P. ichunensis stat. n. (from the Russian Far East and Northern China), and P. filipinus (from the Philippines), which were previously considered subspecies of P. westermani , and reinstated the species name P. pulmonalis (from Japan). We suggest considering the worms from South Korea the Korean variety of P. ichunensis , because Korean specimens are sister and genetically closest to P. ichunensis from Northeast China and Primorsky region of Russia. Worms from South (India (type 2), Sri Lanka), Southeast (Malaysia, Vietnam, Thailand (types 1 and 2)) and East Asia (Taiwan) were left in the paragonimid systematics as Paragonimus sp. We propose to consider Indian worms of type 1 as true P. westermani , but in further revisions, due to the lack of holotype and unknown exact type locality, new type specimens (neotype) should be established., Competing Interests: Conflict of interestThe authors declared that they have no conflict of interest., (© Indian Society for Parasitology 2022.)

In the current study, we raise the issue concerning origins and historical relationships of the trematodes from the families Troglotrematidae and Paragonimidae using phylogenetic analysis and molecular-clock method for estimating evolutionary rates. For the first time we provided 28S rRNA gene fragment (1764 bp) for the type species Troglotrema acutum - zoonotic trematodes that cause cranial lesions (troglotremiasis) in mustelid and canid mammals of the Central Europe, Iberian Peninsula, and North-West Caucasus. Molecular genetic analysis revealed that T. acutum belongs to the monophyletic family Troglotrematidae sister with the family Paragonimidae. The family Troglotrematidae includes five genera: Nanophyetus, Troglotrema, Skrjabinophyetus, Nephrotrema, and Macroorchis; and the family Paragonimidae is monotypic including the only genus Paragonimus. We recover the superfamily Troglotrematoidea for these two families. Divergence of the common ancestor of the superfamily Troglotrematoidea (common troglotrematoid ancestor) likely occurred during the Cretaceous period of the Mesozoic Era and potentially originated in the Asiatic region. The lineage of the family Troglotrematidae is much closer to the common troglotrematoid ancestor than the species of the family Paragonimidae. The radiation time of the common troglotrematoid ancestor (126 Ma, the Early Cretaceous), and formation of the families Troglotrematidae and Paragonimidae (96 Ma and 73 Ma respectively, the Late Cretaceous) corresponds to the time of settling in East Asia by many species of mammaliaforms (about 130-70 Ma)., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

One of the mechanisms underlying the appearance of chronic infections is transition of pathogens into a non-culturable state, which is largely associated with the use of antibiotics. We studied ultrastructure of dormant bacteria Yersinia pseudotuberculosis obtained from the vegetative form of strain 512 by inhibition with kanamycin. On the model of the causative agent of pseudotuberculosis we showed that transition of prokaryotes to a dormant state occurs through apoptosis of bacteria. Fragmentation and condensation of chromatin with the formation of electron-dense fibrils, clumps and large conglomerates characteristic of apoptosis were found in the nucleoid zone of the cytoplasm of inhibited bacterial cells. These results are of great importance for understanding the mechanisms of the existence of pathogens in different conditions, as well as for identifying the causative agents of infectious diseases., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature.)

Inflammatory reactions are part of a complex biological response that plays a vital role in the appearance of various stimuli resulting from tissue and cell damage, the invasion of pathogenic bacteria, and the formation of the subsequent adaptive immune response. The production of many triggers and mediators of inflammation, which are inducers of pro-inflammatory factors, is controlled by numerous differentiation programs, through which inflammation is resolved and tissue homeostasis is restored. However, prolonged inflammatory responses or dysregulation of pro-inflammatory mechanisms can lead to chronic inflammation. Modern advances in biotechnology have made it possible to characterize the anti-inflammatory activity of phlorotannins, polyphenolic compounds from brown seaweed, and the mechanisms by which they modulate the inflammatory response. The purpose of this review is to analyze and summarize the results of numerous experimental in vitro and in vivo studies, illustrating the regulatory mechanisms of these compounds, which have a wide range of biological effects on the body. The results of these studies and the need for further research are discussed.

We investigated the ability of six prenylated prerocarpans, stilbenoid, and a new dimeric flavonoid, lespebicolin B, from stem bark as well as two 3-O-rutinosides and a mixture of 3-O-β-D-glucosides of quercetin and kaempferol from flowers of Lespedeza bicolor to inhibit HSV-1 replication in Vero cells. Pretreatment of HSV-1 with polyphenolic compounds (direct virucidal effect) showed that pterocarpans lespedezol A 2 (1), (6aR,11aR)-6a,11a-dihydrolespedezol A 2 (2), (6aR,11aR)-2-isoprenyldihydrolespedezol A 2 (4), and (6aR,11aR,3'R)-dihydrolespedezol A 3 (5) significantly inhibited viral replication, with a selective index (SI) ≥10. Compound 4 possessed the lowest 50% - inhibiting concentration (IC 50 ) and the highest SI values (2.6 μM and 27.9, respectively) in this test. (6aR,11aR)-2-Isoprenyldihydrolespedezol A 2 (4) also had a moderate effect under simultaneous treatment of Vero cells with the tested compound and virus (IC 50 and SI values were 5.86 μM and 12.4, respectively). 3-O-rutinosides of quercetin and kaempferol and a mixture of 3-O-β-D-glucosides of quercetin and kaempferol (10 and 12) also showed significant virucidal activity, with SI values of 12.5, 14.6, and 98.2, respectively, and IC 50 values of 8.6, 12.2, and 3.6, respectively. We also performed a quantitative structure-activity relationship (QSAR) analysis of data on the virucidal activity of polyphenolics with 4 < pIC 50  < 6. It was found that the virucidal activity of these compounds depended on both the structure of the aromatic part and the conformation of geranyl and isoprenyl side chains of their molecules. These findings are correlated with the largest value of the principal moment of inertia (pmi) descriptor describing the geometry of molecules., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The structural diversity and unique physicochemical properties of sulphated polysaccharides of red algae carrageenans (CRGs), to a great extent, determine the wide range of their antiviral properties. This work aimed to compare the antiviral activities of different structural types of CRGs: against herpes simplex virus type 1 (HSV-1) and enterovirus (ECHO-1). We found that CRGs significantly increased the resistance of Vero cells to virus infection (preventive effect), directly affected virus particles (virucidal effect), inhibited the attachment and penetration of virus to cells, and were more effective against HSV-1. CRG1 showed the highest virucidal effect on HSV-1 particles with a selective index (SI) of 100. CRG2 exhibited the highest antiviral activity by inhibiting HSV-1 and ECHO-1 plaque formation, with a SI of 110 and 59, respectively, when it was added before virus infection. CRG2 also significantly reduced the attachment of HSV-1 and ECHO-1 to cells compared to other CRGs. It was shown by molecular docking that tetrasaccharides-CRGs are able to bind with the HSV-1 surface glycoprotein, gD, to prevent virus-cell interactions. The revealed differences in the effect of CRGs on different stages of the lifecycle of the viruses are apparently related to the structural features of the investigated compounds.

The coexistence of various pathogens inside the patient's body is one of the poorly studied and current issues. The aim of the study is to identify the relationship between the indicators of complex laboratory diagnostics and the clinical manifestations of a mixed disease during subsequent infection with the SARS-CoV-2 virus using the example of a case of chronic encephalitis-borreliosis infection. Seven blood serum samples were collected from the patient over the course of a year. For the etiological verification of the causative agents of TBE, Lyme disease and COVID-19, the methods of ELISA and PCR diagnostics were used. The patient was diagnosed with Lyme disease on the basis of the detection of IgG antibodies to Borrelia 5 months after the onset of the disease, since she denied the tick bite. In the clinical picture, there was an articular syndrome and erythema migrans. Later, IgG antibodies to the TBEV were found in the blood. Throughout the study, IgM antibodies to Borrelia were not detected. The exacerbation of Lyme disease could be judged by the clinical manifestations of this disease and by the growth of specific IgG antibodies. A feature of this case was that during an exacerbation of the Lyme disease, an infection with the SARS-CoV-2 virus occurred. Treatment (umifenovir, hydroxychloroquine, azithromycin, ceftriaxone) was prescribed, which improved the condition of the underlying disease, decreased joint pain, decreased IgG levels to borrelia. However, during this period, serological markers of TBEV appear: antigen, IgM antibodies, and the titer of IgG antibodies increases. Most likely, this was facilitated by the switching of the immune system to the SARS-CoV-2 virus, with the simultaneous suppression of borrelia with antibiotics and the appointment of hydroxychloroquine, which has an immunosuppressive effect. Despite the activation of the virus, clinical manifestations of TBE were not observed in the patient, which is most likely associated with infection with a weakly virulent TBEV strain. The further course of tick-borne infections revealed the dominant influence of B. burgdorferi in relation to TBEV. Laboratory studies have shown that suppression of the activity of the borreliosis process by etiotropic treatment subsequently led to the activation of the persistent TBEV., Competing Interests: The authors declare no conflict of interest.

This review presents materials characterizing sulfated polysaccharides (SPS) of marine hydrobionts (algae and invertebrates) as potential means for the prevention and treatment of protozoa and helminthiasis. The authors have summarized the literature on the pathogenetic targets of protozoa on the host cells and on the antiparasitic potential of polysaccharides from red, brown and green algae as well as certain marine invertebrates. Information about the mechanisms of action of these unique compounds in diseases caused by protozoa has also been summarized. SPS is distinguished by high antiparasitic activity, good solubility and an almost complete absence of toxicity. In the long term, this allows for the consideration of these compounds as effective and attractive candidates on which to base drugs, biologically active food additives and functional food products with antiparasitic activity.

The Hantaan orthohantavirus (genovariant Amur-AMRV) is a rodent-borne zoonotic virus; it is the causative agent of haemorrhagic fever with renal syndrome in humans. The currently limited therapeutic options require the development of effective anti-orthohantavirus drugs. The ability of native fucoidan from Fucus evanescens (FeF) and its enzymatically prepared high-molecular-weight (FeHMP) and low-molecular-weight (FeLMP) fractions to inhibit different stages of AMRV infection in Vero cells was studied. The structures of derivatives obtained were determined using nuclear magnetic resonance (NMR) spectroscopy. We found that fucoidan and its derivatives exhibited significant antiviral activity by affecting the early stages of the AMRV lifecycle, notably virus attachment and penetration. The FeHMP and FeLMP fractions showed the highest anti-adsorption activity by inhibiting AMRV focus formation, with a selective index (SI) > 110; FeF had an SI of ~70. The FeLMP fraction showed a greater virucidal effect compared with FeF and the FeHMP fraction. It was shown by molecular docking that 2 O -sulphated fucotetrasaccharide, a main component of the FeLMP fraction, is able to bind with the AMRV envelope glycoproteins Gn/Gc and with integrin β3 to prevent virus-cell interactions. The relatively small size of these sites of interactions explains the higher anti-AMRV activity of the FeLMP fraction.

The quinoid pigment echinochrome A isolated from the sea urchin Scaphechinus mirabilis, the product of its oxidation dehydroechinochrome, and structurally similar antiviral agent oxolin were tested for their ability to inhibit plaque formation induced by herpes simplex virus type 1 (HSV-1) in Vero cells. The tested compounds showed significant anti-HSV-1 activity, mainly due to their direct effect on viral particles and on virus attachment to cells. The antiviral efficacy of the test compounds increased in the following order: oxolin→echinochrome A→dehydroechinochrome., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

Hemostasis disorders play an important role in the pathogenesis, clinical manifestations, and outcome of COVID-19. First of all, the hemostasis system suffers due to a complicated and severe course of COVID-19. A significant number of COVID-19 patients develop signs of hypercoagulability, thrombocytopenia, and hyperfibrinolysis. Patients with severe COVID-19 have a tendency toward thrombotic complications in the venous and arterial systems, which is the leading cause of death in this disease. Despite the success achieved in the treatment of SARS-CoV-2, the search for new effective anticoagulants, thrombolytics, and fibrinolytics, as well as their optimal dose strategies, continues to be relevant. The wide therapeutic potential of seaweed sulfated polysaccharides (PSs), including anticoagulant, thrombolytic, and fibrinolytic activities, opens up new possibilities for their study in experimental and clinical trials. These natural compounds can be important complementary drugs for the recovery from hemostasis disorders due to their natural origin, safety, and low cost compared to synthetic drugs. In this review, the authors analyze possible pathophysiological mechanisms involved in the hemostasis disorders observed in the pathological progression of COVID-19, and also focus the attention of researchers on seaweed PSs as potential drugs aimed to correction these disorders in COVID-19 patients. Modern literature data on the anticoagulant, antithrombotic, and fibrinolytic activities of seaweed PSs are presented, depending on their structural features (content and position of sulfate groups on the main chain of PSs, molecular weight, monosaccharide composition and type of glycosidic bonds, the degree of PS chain branching, etc.). The mechanisms of PS action on the hemostasis system and the issues of oral bioavailability of PSs, important for their clinical use as oral anticoagulant and antithrombotic agents, are considered. The combination of the anticoagulant, thrombolytic, and fibrinolytic properties, along with low toxicity and relative cheapness of production, open up prospects for the clinical use of PSs as alternative sources of new anticoagulant and antithrombotic compounds. However, further investigation and clinical trials are needed to confirm their efficacy.

The disease-preventive and medicinal properties of plant polyphenolic compounds have long been known. As active ingredients, they are used to prevent and treat many noncommunicable diseases. In recent decades, marine macroalgae have attracted the attention of biotechnologists and pharmacologists as a promising and almost inexhaustible source of polyphenols. This heterogeneous group of compounds contains many biopolymers with unique structure and biological properties that exhibit high anti-infective activity. In the present review, the authors focus on the antiviral potential of polyphenolic compounds (phlorotannins) from marine algae and consider the mechanisms of their action as well as other biological properties of these compounds that have effects on the progress and outcome of viral infections. Effective nutraceuticals, to be potentially developed on the basis of algal polyphenols, can also be used in the complex therapy of viral diseases. It is necessary to extend in vivo studies on laboratory animals, which subsequently will allow proceeding to clinical tests. Polyphenolic compounds have a great potential as active ingredients to be used for the creation of new antiviral pharmaceutical substances.

Background and Aim: Uncinaria infection often appears in domestic dogs. In the present study, parasitological examination of fecal samples from 782 dogs were analyzed for the presence of Uncinaria stenocephala ., Materials and Methods: Fecal samples were analyzed by means of a standardized flotation method using a saturated salt solution containing NaNO 3 (specific gravity 1.38), with a centrifugation step., Results: The highest prevalence rates were found among young adult dogs (8.3%), followed by puppies (5.4%); the lowest prevalence rates were found in dogs older than 3 years (4.3%). The prevalence was 5.8% among female dogs and 7.2% in male dogs. Coinfections with roundworms and protozoan parasites were frequently observed in U. stenocephala -positive dogs (15%). In total, three types of coinfections were registered. Coinfection of U. stenocephala + Sarcocystids oocysts was recorded in 19.1% of the dogs (n=10). This may relate to higher prevalence of S. oocysts in dogs (n=153; 19.5%). There were two cases of coinfection of U. stenocephala + Toxocara canis (3.9%), which may relate to low prevalence of T. canis (3.9 %). One case of coinfection of Dipylidium caninum + U. stenocephala (0.1%) also appeared., Conclusion: The present study showed that male dogs and young dogs were most susceptible to U. stenocephala infection., (Copyright: © Yur’evich, et al.)

Canine demodicosis is a common skin disorder with multiple risk factors, including age and breed predisposition. There is relatively limited information about the risk factors for canine demodicosis in large canine populations. This retrospective case-control study was conducted by searching the electronic records of dogs with skin lesions for the presence of Demodex mites in skin scrapings. Diagnosis of demodicosis was based on the presence of skin lesions and mites in skin scrapings. Multivariate analysis was conducted using logistic regression analysis to estimate the relative risk and odds ratio of variables hypothesized to influence the risk of canine demodicosis, such as age, sex, breed, season, and parasitic infection. The results of multivariate logistic regression analysis showed a positive correlation between the dogs' age and demodicosis. Dogs older than three years, as well as puppies, had a high risk of demodicosis (P0.05). Breeds with the greatest association (odds ratio) with demodicosis included the American Staffordshire Terrier (OR=0.9) and Moscow Watchdog (OR=0.2). The presence of intestinal parasites, such as Diphyllobothrium latum, was significantly associated with demodicosis.

Lassa fever is a severe viral hemorrhagic illness caused by Lassa virus. Based on estimates, the number of LASV infections ranges from 300,000 to 500,000 cases in endemic areas with a fatality rate of 1%. Development of fast and sensitive tools for the control and prevention of Lassa virus infection as well as for clinical diagnostics of Lassa fever are crucial. Here we reported development and evaluation of a one-step quantitative RT-qPCR assay for the Lassa virus detection - LASV-Fl. This assay is suitable for the detection of lineages I-IV of Lassa virus. The limit of detection of the assay ranged from 10 3 copies/ml to 10 5 copies/ml and has 96.4% diagnostic sensitivity, whereas analytical and diagnostic specificities both were 100%. Serum, whole blood and tissue are suitable for use with the assay. The assay contains all the necessary components to perform the analysis, including an armored positive control (ARC+) and an armored internal control (IC). The study was done during the mission of specialized anti-epidemic team of the Russian Federation (SAET) in the Republic of Guinea in 2015-2018. Based on sequencing data, LASV-specific assay was developed using synthetic MS2-phage-based armored RNA particles, RNA from Lassa virus strain Josiah, and further, evaluated in field conditions using samples from patients and Mastomys natalensis rodents., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Paramushir virus belongs to Sakhalin virus genogroup within Orthonairovirus genus and is one of the poorly studied viruses with unknown pathogenicity. At the moment, only one nearly complete sequence of Paramushir virus genome, isolated in 1972, is available. Two new strains of PARV were isolated in 2015 from a sample collected at the Tyuleniy Island in the Okhotsk Sea and sequenced using a combination of high throughput sequencing and specific multiplex PCR. Both strains are closely related to the early sequenced PARV strain LEIV-1149 K. The signs of intersegment reassortment and probable recombination were revealed, which point to a high variability potential of Paramushir virus and may lead to the formation of strains with novel properties, different from those of the predecessors. The new data regarding Paramushir virus can promote a better understanding of the diversity and relations within Orthonairovirus genus and help define intragenic demarcation criteria, which have not yet been established., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

Introduction: The new reassortant of the swine flu virus A(H1N1)pdm09, which emerged in 2009, overcame the species barrier and caused the 2009-2010 pandemic. One of the key points required for the influenza virus to overcome the species barrier and adapt it to humans is its specific binding to the receptors on the epithelium of the human respiratory tract., Purpose: Studying the dynamics of changes in receptor specificity (RS) of the HA1 subunit of the hemagglutinin of the influenza A(H1N1)pdm09 virus strains isolated during the period 2009-2016 on the territory of the Russian Federation, and an analysis of the possible impact of these changes on the incidence rates of the population of the Russian Federation of pandemic influenza in certain epidemic seasons., Material and Methods: Standard methods of collecting clinical materials, isolation of influenza viruses, their typing and genome sequencing were used. For the study of RS of influenza A virus (H1N1)pdm09, the method of solid phase sialosidenzyme analysis was used., Results: It is shown that the change in the parameter W 3/6 , which characterizes the degree of a2-3 receptor specificity (a2-3-RS) of the influenza virus A(H1N1) pdm09 over a2-6-RS, coincides with the change in the incidence rates of the Russian Federation's pandemic flu in separate epidemic seasons. There is a tendency to increase the affinity of the virus A(H1N1)pdm09 to α2-3 analogs of the sialyl-glycan receptors of the human respiratory tract epithelium - α2-3-sialoglycopolymers (α2-3-SGP), and falls to α2-6-SGP, with the virus showing the greatest affinity for sulfated sialoglycopolymers., Discussion: Screening for RS strains of influenza A (H1N1)pdm09 virus isolated on the territory of the Russian Federation in 2009-2016 revealed a decrease in the affinity of viruses for a2-6-sialosides, especially for 6'SL-SGP, which is probably due to the presence of amino acid substitutions in the 222 and 223 positions of RBS HA1 viruses. Previous studies have shown that the presence of such substitutions correlates with an increase in the virulence of the influenza A virus (H1N1)pdm09 [16, 23]. Probably, the pandemic virus has evolved towards the selection of more virulent pneumotropic variants., Conclusion: Monitoring of the receptor specificity of a pandemic influenza virus makes it possible to identify strains with altered RS to the epithelium of the human respiratory tract and an increased ability to transfer from person to person. Change in the period 2009-2016 the W 3/6 parameter characterizing the degree of α2-3-RS excess of the influenza A(H1N1)pdm09 virus over α2-6-RS, coincides with the change in the incidence rates of the pandemic influenza population of the Russian Federation in certain epidemic seasons., Competing Interests: The authors declare no conflict of interest.

Rabies virus is endemic to Russia, among other countries. It is therefore critical to develop a high-quality and high-precision diagnostic procedure for the control and prevention of infection. The main objective of the research presented here was to develop a reliable RT-qPCR assay for rabies diagnostics. For this purpose, a RABV strains from various biological and geographical origins were used. In addition, rabies-positive and rabies-negative samples, as well as nucleic acids from other viruses and DNA extracted from the brain tissues of mice, dogs, cats, bats and humans, were studied using the developed assay. The analytical sensitivity of the assay, as assessed using armored recombinant positive control dilutions, was 10 3 copies/ml, and the sensitivity measured using characterized strains was between 0.1 LD50/ml and 1.0 LD50/ml. A broad range of RNA from RABV strains circulating in different regions of Russia, as well as RNA from RABV-positive primary brain samples from 81 animals and two humans, was detected using the developed assay. No false-positive or false-negative results were obtained. Given that high analytical and diagnostic sensitivities and a high specificity were verified for this assay, it has high potential as a screening test that may be suitable for the epizootiological monitoring of animals and for the fast postmortem diagnosis of rabies., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The bunyaviral monogeneric family Nairoviridae currently includes 12 species for 35 distinct viruses. Here, we present the complete genome coding sequences of an additional seven nairoviruses. Five of them can be assigned to established species, whereas two of them (Artashat and Chim viruses) ought to be assigned to two novel species.

Near complete rabies virus N gene sequences (1,110 nt) were determined for 82 isolates obtained from different regions of Russia between 2008 and 2016. These sequences were analyzed together with 108 representative GenBank sequences from 1977-2016 using the Bayesian coalescent approach. The timing of the major evolutionary events was estimated. Most of the isolates represented the steppe rabies virus group C, which was found over a vast geographic region from Central Russia to Mongolia and split into three groups (C0-C2) with discrete geographic prevalence. A single strain of the steppe rabies virus lineage was isolated in the far eastern part of Russia (Primorsky Krai), likely as a result of a recent anthropogenic introduction. For the first time the polar rabies virus group A2, previously reported in Alaska, was described in the northern part of European Russia and at the Franz Josef Land. Phylogenetic analysis suggested that all currently circulating rabies virus groups in the Russian Federation were introduced within the few last centuries, with most of the groups spreading in the 20th century. The dating of evolutionary events was highly concordant with the historical epidemiological data.

Aim: To assess correlation of cytokines levels and therapy regimes a relationship of the time course of changes in the cytokines IFN-γ, IFN-α, IL-18, and TNF-α to the treatment option for influenza A (H1N1) pdm09 with umifenovir (Arbidol) 800 mg/day for 5 days (n=50); oseltamivir (Tamiflu) 150 mg/day for 5 days (n=50); umifenovir (Arbidol) 800 mg/day for 5 days in combination with Kagocel 72 mg/day for 2 days.; 36 mg/day for 2 days (n=50); oseltamivir (Tamiflu) (150 mg/day for 5 days) in combination with Kagocel 72 mg/day for 2 days; 36 mg/day for 2 days (n=50). A comparison group consisted of 30 healthy volunteers., Material and Methods: The state of immunologic reactivity was assessed twice: at admission of the patients to an infectious disease clinic (at 1-3 disease days) and in the early convalescent period (at 7-8 disease days): venous blood samples were collected to determine the concentrations of IFN-γ, IFN-α, IL-18, and TNF-α by a solid-phase enzyme immunoassay., Results: All the patients in the acute phase of influenza A showed a statistically significant increase in the levels of IFN-γ, IFN-α, and IL-18 as compared with the control group. The groups receiving monotherapy in the early convalescent period had a decrease in the IFN-γ, IFN-α, and IL-18 concentrations that could be compensated by the combined use of the immunomodulator Kagocel. No statistically significant changes in the levels of TNF-α were found in the patients of all the groups, but the groups receiving monotherapy exhibited its lower concentrations in the convalescence period., Conclusion: The combination of etiotropic antiviral drugs with Kagocel enhances the efficiency of antiviral therapy. Monitoring of antiviral cytokines during the treatment of influenza A is a convenient tool to verify the efficiency of antiviral therapy and needs to be more widely introduced into medical practice.

Twenty years ago in the South Chinese province of Guangdong the epizooty of highly pathogenic avian influenza (HPAI) H5N1 virus, which has laid the foundation of the largest epizooty in the contemporary history, has flashed. Hemagglutinin of prototype A/goose/Guangdong/1/1996 (H5N1) changing many times and generating new genetic subgroups participated in various reassortations; it still exists today. The present review is devoted to the retrospective analysis of HPAI/H5N1evolution for the last twenty years in the territory of Eurasia, Africa and America. The basis for the discussion is ecological model according to which new genetic variants are formed in the migration pathways with close contacts between different bird populations and in the overwintering areas where the maximum values of the immune layer occur; amplification of virus variants occurs in nesting areas among juvenile populations. The updated system of designations of genetic groups introduced by WHO/OIE/FAO H5 Evolution Working Group in 2015 is used.

An attack of a brown bear (Ursus arctos) on human was detected in November, 2014 in the Barabash village (Khasan region of the Primorski krai) located in close proximity to the national park Land of the Leopard. The bear was shot. The deviant behavior of the bear indicated the possibility of rabies. The diagnosis was confirmed by means of laboratory methods. The strain RABV/Ursus arctos/Russia/Primorye/PO 01/2014 (further PO 01) was isolated from the brain of the bear. PO 01 is the first completely sequenced Far Eastern strain of RABV. It can be considered as topotypic. PO 01 considerably differs from the vaccine strain RV 97 (GenBank EF542830) that is the basis of attenuated vaccine applied in the Land of the Leopard. At the same time, the immunodominant sites in PO 01 and RV 97 proteins differ slightly. It can be recommended to continue application of the vaccine. The analysis of the PO 01 genome (GenBank KP997032) revealed its belonging to the Eurasian genetic subgroup of the genotype 1 (street rage). Thus, this genetic subgroup stretches to the East. Expansion of the cross-border protected territories of Russia and China in the Far East demands the correct statistics of circulation of the lyssaviruses to be kept.

Survey data from autopsy specimens from patients who died from pneumonia caused by the influenza A(H1N1) pdm09 in 2012-2014 and mutant forms of influenza virus in these patients (position 222 in the receptor-binding region of hemagglutinin) were presented. In total, according to aggregate data, obtained with three different methods (sequencing, next-generation sequencing (NGS), virus isolation) mutant viruses were detected in 17 (41%) from 41 patients. The proportion of the mutant forms in viral populations ranged from 1% to 69.2%. The most frequent mixture was the wild type (D222) and mutant (D222G), with proportion of mutant type ranged from 3.3% to 69.2% in the viral population. Mutation D222N (from 1.1% to 5.5%) was found rarely. Composition of the viral population from one patient is extremely heterogeneous: in left lung there was only wild type D222, meantime in right lung - mixture of mutant forms 222D/N/G (65.4/32.5/1.1%), in trachea - mixture 222D/G/Y/A (61.8/35.6/1.2/1.4%, respectively), and in bronchi compound of 222D/G/N/A (64.3/33.7/1/1%, respectively) were detected. The obtained data indicate that the process of adaptation of the virus in the lower respiratory tract is coupled with the appearance of different virus variants with mutations in the receptor-binding region. Mutant forms of the virus are observed in the lower respiratory tract of the majority of patients with lethal viral pneumonia. However, if they are a minor part of the population, they cannot be detected by the method of conventional sequencing. They can be identified using the NGS methods.

We report here the complete genome sequence (GenBank KP997032) of rabies virus strain RABV/Ursus arctos/Russia/Primorye/PO-01/2014, isolated in November 2014 from a brown bear (Ursus arctos) that attacked a person in Primorsky Krai (Russian Federation). This strain was clustered into the Eurasian genetic subgroup of genotype 1 (street rage)., (Copyright © 2016 Shchelkanov et al.)

We report here the complete genome sequence of a Newcastle disease virus (NDV) isolate, NDV/Altai/pigeon/770/2011, isolated from a rock dove in the Russian Federation. On the basis of phylogenetic analysis, this strain was clustered into genotype VIb class II., (Copyright © 2015 Yurchenko et al.)

Almost complete nucleotide sequences for the S, M, and L segments were obtained for three strains of the Batai virus (Bunyamwera serogroup, genus Orthobunyavirus, Bunyaviridae family). Based on the results of the phylogenetic analysis conducted forthe three genomic segments LEIV Ast507 and LEIV-Ast528 strains were grouped with other European BATV isolates and were found to be almost identical to the strain 42 isolated from Volgograd Region, Russia, 2003. Surprisingly, LEIV-13395 strain isolated from the Aedes sp. mosquitos in Magadan Oblast, 1987, turned out to be a novel genotype inside Bunyamwera serogroup. The highest nucleotide identity levels of LEIV-13395 genomicsegments (86.9%, 80.8%, 79.7% for S, M and L segments respectively) were observed with corresponding segments of the Batai virus.

Fifty-four strains of H5N1 highly pathogenic avian influenza (HPAI) virus were isolated from wild birds in the ecosystems of northern Eurasia and from poultry in the south of western Siberia (July 2005), at the mouth of Volga River (November 2005), at Uvs-Nur Lake on the boundary of the Great Lakes Depression in western Mongolia and the Tyva Republic of Russia (June 2006), in the vicinity of Moscow (February 2007), in the southeastern part of the Russian Plain (September 2007 and December 2007), and in the far east (April 2008) of the Russian Federation and were phenotypically characterized and deposited into the Russian state collection of viruses. Complete genome nucleotide sequences for 24 strains were obtained and deposited into GenBank. In all cases when strains were isolated from both wild birds and poultry in the same outbreak these strains were genetically closely related to each other. Until 2008 all HPAI H5N1 strains isolated in northern Eurasia clustered genetically with the viruses from Kukunor Lake (Qinghai Province, China), known as genotype 2.2 or the "Qinghai-Siberian" genotype. The viruses from the Qinghai-Siberian genotype have continued to evolve from those initially introduced into western Siberia in 2005 into two genetic groups: "Iran-North Caucasian" and "Tyva-Siberian." In vitro replication potential (50% tissue-culture infectious dose in porcine embryo kidney) of Qinghai-Siberian strains decreased over time, which could reflect decreasing virulence. Comparison of genome sequences with biological characteristics of the respective strains permitted us to identify point mutations in PB2, PB1, PA, HA, NP, NA, M2, NS1, and NS2 that possibly influenced the level of replication potential. The HPAI H5N1 virus, which penetrated into the south of the Russian Far East in spring 2008, belonged to genotype 2.3.2.

Studies of the interactions of vertebrates, viruses and arthropod vectors of these viruses were monitored in terms of different ecological groups of viruses transmitted by mosquitoes and ticks in Northern Eurasia in an area encompassing more than 15 million km2. About 90 viruses were isolated, including 24 new to science. Newly recognized infections of vertebrates, including humans, were described. Many unusual epidemic situations were analysed. Permanent efforts were established to prevent bioterrorist activities and their consequences. Extensive epidemic outbreaks of West Nile fever (WNF; i.e., fever caused by West Nile virus) and Crimean-Congo hemorrhagic fever (CCHF) with unusual high mortality appeared in the last four years in southern Russia. We determined infection rates in humans, domestic and wild animals, mosquitoes and ticks from natural and synanthropic biocenoses [Editorial note: "synanthropic" means, roughly, all species living with (c.f. lice, fleas) or near people, such as in houses (c.f. house mice), parks (c.f. Rattus spp.), and the like, rather like "peridomestic", but not strictly so; "biocenosis" is the biome, the "totality of living populations in a particular habitat, which itself is only a part of the ecosystem".]. CCHF virus strains were phylogenetically similar to strains isolated in this area 35 years ago but different from Central-South-Asian and African strains. Before the outset of the current emergence of epidemic WNF, three genetic variants of this virus had been isolated in USSR, two African and one Indian. Phylogenetic analysis of complete genome sequences of epidemic strains demonstrated considerable similarity to strains from USA and Israel and differences from strains isolated in the same USSR areas 20-30 years before. In addition to strains of genotype 1, we isolated strains of second and third lineages and a strain of a fourth genetic variant. Nucleotide differences of these strains from all three genotypes was about 30%. The emerging WNF situation in Russia for the last 4 years probably has been the result of not only natural and social factors, but also to introduction of more virulent strains or by evolution of the virus.

A distributed model of anaerobic digestion of solid waste was developed to study effects of mass transfer on the rate of propagation of initiation methanogenic area. The diffusion and advection of volatile fatty acids (VFA) and methanogenic biomass were taken into account in the model of a one-dimensional (ID) reactor. It was considered that VFA inhibits both polymer hydrolysis and acetoclastic methanogenesis. This approach allows to view the bioreactor as an active medium that provokes concentration waves from some area of methanogenic initiation (local VFA depression) to the total reactor volume. The model shows that mass transfer-based acceleration of methane production in the reactor is possible when the intensity of VFA utilization in the methanogenic area is sufficient for a complete digestion of the incoming VFA. Otherwise, initiation methanogenic area will be suppressed by increasing concentration of VFA. The obtained results emphasize the importance of considering spatial heterogeneity of the reaction for the analysis of solid anaerobic digestion in bioreactors and landfills. The digestion of solid waste can be optimized by setting the low rate of mass transfer (mixing or leachate recirculation) during lag-phase of the reaction with subsequent increase in the mass transfer rate in parallel with the propagation of methanogenic population. In this case, the rate of concentration waves substantially increases.

Previously, when discussing the properties of one parameter discrete model of genetic diversity (M.Yu. Shchelkanov et al, J. Biomol. Struct. Dyn. 15, 887-894 (1998)), we took into account Hamming distance distribution only between precursor and arbitrary descendant sequences. However, really there are sets of sequence populations produced during amplification process. In the presented work we have investigated Hamming distance distributions between sequences from different descendant sets produced in the frame of one parameter discrete model. Two basic descendant generation operators (so called amplifiers) are introduced: 1) the last generation amplifier, L, which produces descendants with precursor elimination; 2) all generations amplifier, G, which produces descendants without precursor elimination. Generalization of one-parameter discrete model for the case when precursor sequences do not coincide are carried out. Using this generalization we investigate the distribution of Hamming distances between L- and G-generated sequences. Basic properties of L and G operators, L/G-choice alternative problem have been discussed. Obtained results have common theoretical significance, but they are more suitable for high level genetic diversity process (for example, HIV diversity).

Stochastic properties of previously introduced one parameter discrete model of genetic diversity (M. Yu. Shchelkanov et al, J. Biomol. Struct. Dyn. 15, 887-894 (1998)) are investigated. Two approaches are compared: (A) when the on-step substitution number and/or the number of substitution steps are random variables; (B) referred parameters are replaced by mathematical expectations of the respective variables. It has been demonstrated, that estimations of sequence measure based on the number of replication steps are more under the assumption of case (A) as compared with (B). Thus, real biological situation relating to the case (A) could additionally promote the increasing of distinctions between different taxons (e.g. HIV, etc.). Peculiarities of one-parameter discrete model of genetic diversity during calculation of the distinctions between symbol (e.g. nucleotide) sequence sets are also discussed.

Changes in dehydrogenase activity of some continuous cell lines were studied during the response to acute infection in vitro with HIV-1 variants having different biological features. Soon after infection, the dehydrogenase activity of infected cells increased, and this increase was greater and more prolonged with the HIV-1 r/h variant than with the HIV-1 s/l variant. Later stages showed decreased dehydrogenase activity of HIV-1-infected cells compared to the noninfected control; this is a manifestation of the cytodestructive effect of the virus. The changes increased monotonously (but not in direct proportion) with an increase in the infecting dose.

With the help of previously introduced enumeration procedure (M.Yu. Shchelkanov, A.N. Yudin, A.V Antonov, N.S. Starikov, A.A. Vedenov, E.V. Karamov, J. Biomol. Struct. Dyn. 15, 217-229 (1997)) and probability distribution function for the enumeration after some substitution steps (M.Yu. Shchelkanov, L.A. Soinov, V.V. Zalunin, D.A. Gumennyi, A.N. Yudin, A.A. Natan, V.B. Kireev, E.V. Karamov, J. Biomol. Struct. Dyn. 15, N 4, (1998)) we have demonstrated that dependencies of replication acts number on Hamming distance are identical for one-parameter discrete models of both direct and parallel genetic diversity.