VIRUSES OF NEPOVIRUS GENUS (PICORNAVIRALES, SECOVIRIDAE) IN THE SOUTH OF THE FAR EAST: RESULTS OF LONGITUDINAL MONITORING

Abstract. The aim of the presented work consists in the analysis of results of long-term monitoring of the members of one of the most important and interesting phytovirus taxons – genus Nepovirus (Picornavirales, Secoviridae, Comovirinae) – which is carried out since 1962 on the planned basis in the south of the Far East (Primorsky krai, Khabarovsk krai, the Sakhalin region) by the Laboratory of Virology of Federal Scientific Center of the East Asia terrestrial biodiversity of Far Eastern Branch of Russian Academy of Sciences (Vladivostok, Russia). Discussion. Many (it is possible – all) nepoviruses are capable to cause epiphytoties with significant economic damage for world economy. In the current article the organization of nepovirus genome, the principles of their division into three genetic groups (A, B, and C), virion morphology, the principles of division into three beyond density fractions (T, M, and B), the characteristics of phytopathology connected with nepoviruses, their ecology in the south of the Far East (including sources of isolation and vectors) are discussed as well as physical-chemical properties of some the most interesting strains from this region which apparently could represent new species of Nepovirus genus: Phryma asiatica mosaic virus (PhAMV); dayflower mosaic virus (DFMV); foenugreek necrotic spot virus (FoNSV); Capsicum annuum necrotic spot virus (CaNSV). Conclusion. Nepovirus genus is one of the most adapted for circulation in the phytocenoses of midlatitudes having natural reservoir among wild plants and pose serious threat for crops. On the basis of ecological features of nepoviruses the scientifically based list of preventive and protective actions against epiphytoties with nepovirus nature is provided. One of the most important elements of such actions is their planned monitoring at the regional level with obligatory comparison of the received results to universal data

SEAL LOUSE (ECHINOPHTHIRIDAE) AS VECTORS FOR INVASIVE AND INFECTIOUS DISEASE AGENTS OF PINNIPEDS

The aim of the presented article is to analyze seal lice (Phthiraptera: Anoplura, Echinophthiridae) adaptation to aquatic environment – permanent parasites of pinnipeds, as well as available literature data about seal lice as pathogen vectors of their hosts. Discussion. The most noticeable feature of seal lice adaptation to aquatic environment has become their movement in the nasal passages of pinnipeds. However, this does not mean a complete rejection of ecto - in favor of endoparasitism. Seal lice preserved morphology-functional mechanisms of attachment to the fur and gained a number of features that facilitate the existence in the aquatic environment: the abdominal spiracles are tapered and have tube-like shape; head, thorax and especially the abdomen is covered with scale-like flattened setae, which stick to the air bubbles. The close ecological connection with the pinnipeds makes bloodsucking seal lice effective carriers of etiological agents of invasive and infectious diseases, e.g. microfilaria Acanthocheilonema spirocauda (Nematoda: Onchocercidae), Southern elephant seal virus (SESV) (Togaviridae, Alphavirus), Bartonella henselae (Rhizobiales: Bartonellaceae). Symbiont of Proechinophthirus fluctus described in 2016 was classified to the group of spotted fever Rocky mountain (Rickettsia ricketsii), which includes etiological agents of dangerous human diseases. Conclusion. It is necessary to include investigations of seal lice of pinnipeds into the programs of ecology-zoological and ecologyvirological monitoring of marine mammals

Antiviral Effects and Mechanisms of Action of Water Extracts and Polysaccharides of Microalgae and Cyanobacteria

Microalgae (MA) and cyanobacteria (CB) are currently attracting much attention from scientists due to the high biological activity of many secondary metabolites of these aquatic organisms. This review presents up-to-date modern data on the prospects for using polysaccharides (PS) of these marine aquatic organisms as effective and practically safe antiviral agents. These natural biopolymers are polyvalent compounds, which allows them to bind to several complementary biological target receptors. Particular emphasis is placed on the exopolysaccharides (EPS) Spirulina sp. (Arthrospira sp.), Porphyridium sp., Chlorella sp., and Euglena sp., whose antiviral activity makes them promising for the creation of drugs, biologically active food supplements, and products for functional nutrition. The mechanisms of the biological action of PS and the targets of these compounds are presented with a brief description of PS's anti-inflammatory, immunomodulatory and antioxidant actions, which make the most significant contribution to the antiviral effects. The authors hope to draw the attention of researchers to the use of water extracts and polysaccharides of microalgae and cyanobacteria as potential broad-spectrum antiviral agents that can become the basis for new antivirus strategies

Antiviral Effects of Polyphenols from Marine Algae

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

The Potency of Seaweed Sulfated Polysaccharides for the Correction of Hemostasis Disorders in COVID-19

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 phylodynamics of the rabies virus in the Russian Federation

<div><p>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 20^th century. The dating of evolutionary events was highly concordant with the historical epidemiological data.</p></div

Bayesian phylogenetic analysis of near-complete N-gene sequences of the rabies virus strains circulating in the Russian Federation.

<p>Scale bar shows time in years. Branches are color-coded according to described groups. Node posterior probabilities above 95% are shown by black squares at the relevant nodes. Posterior probabilities between 80–95% are indicated by numbers. Posterior probabilities below 80% are not indicated. Sequences obtained in the current study are shown in bold.</p