Publications by authors named "Yuri S Tokarev"

The Siberian moth, Dendrolimus sibiricus is a dangerous forest defoliator, the number one pest of boreal forests in Asia. Search for effective and ecologically friendly control measures drives attention to microbial pathogens. Viruses and microsporidia are obligate intracellular parasites widespread in insect populations causing either chronic or acute infections.

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Recently, we found that the spongy moth L. is susceptible to infection by a Dendrolimus sibiricus cytoplasmic polyhedrosis virus (DsCPV-1). In the present study, we evaluated the pathogenicity of DsCPV-1 against larvae and its impact on surviving insects after the infection.

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Species of the genus are characterized by a multitrophic lifestyle of being arthropod parasites, rhizosphere colonizers, endophytes, and saprophytes. The process of adaptation to various organisms and substrates may lead to specific physiological alterations that can be elucidated by passaging through different hosts. Changes in virulence and cultivation properties of entomopathogenic fungi subcultured on different media or passaged through a live insect host are well known.

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Now more than ever researchers provide more and more evidence that it is necessary to develop an ecologically friendly approach to pest control. This is reflected in a sharp increase in the value of the biological insecticide market in recent decades. In our study, we found a virus strain belonging to the genus (Reoviridae); the strain was isolated from , possessing attractive features as a candidate for mass production of biological agents for lepidopteran-pest control.

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Nosemosis type C is a dangerous and widespread disease of the adult European honey bee and is caused by the spore-forming intracellular parasite . The search for new ways of therapy for this disease is complicated due to the seasonal availability of -infected insects as well as the lack of a developed system for the pathogen's cultivation. By carrying out trials which used different infectious dosages of the parasite, spore storage protocols, host age, and incubation temperatures, we present a simple, safe, and efficient method of propagation in artificially infected worker bees in the laboratory.

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The microsporidium Nosema pyrausta is an important mortality factor of the European corn borer, Ostrinia nubilalis. The present study was aimed at N. pyrausta virulence testing to the beet webworm (BW), Loxostege sticticalis.

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The gypsy moth, , is a notorious forest defoliator, and various pathogens are known to act as natural regulators of its population density. As a widespread herbivore with a broad range of inhabited areas and host plants, it is potentially exposed to parasitic microorganisms from other insect hosts. In the present paper, we determined the susceptibility of gypsy moth larvae to the microsporidium from the European corn borer, .

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Loma acerinae is a xenoma-forming fish microsporidium described from common ruffe Gymnocephalus cernua (Perciformes: Percidae) and also found in Ponto-Caspian gobies (Gobiiformes: Gobiidae). This casts doubt on the strict host specificity of this parasite. The largest subunit RNA polymerase II (rpb1) was used as a genetic marker of the parasite isolated from six host species of Perciformes (G.

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Assembling and powering ribosomes are energy-intensive processes requiring fine-tuned cellular control mechanisms. In organisms operating under strict nutrient limitations, such as pathogenic microsporidia, conservation of energy via ribosomal hibernation and recycling is critical. The mechanisms by which hibernation is achieved in microsporidia, however, remain poorly understood.

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Zophobas morio is a tropical darkling beetle which is widely exploited for commercial large-scale insect growing. Outbreaks of a disease may occur causing total devastation of cultures. In the present paper, samples of diseased Z.

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A new species and a new genus of a microsporidium Alternosema bostrichidis isolated from an adult Prostephanus truncatus in Mexico and from three species of the genus Dinoderus in Nigeria are described. The microsporidium is monomorphic, monoxenic, and develops in direct contact with host cell cytoplasm. The infection first appears with thoracic muscles, followed by a generalized invasion of the host.

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The microsporidian genera Nosema and Vairimorpha comprise a clade described from insects. Currently the genus Nosema is defined as having a dimorphic life cycle characterized by diplokaryotic stages and diplosporoblastic sporogony with two functionally and morphologically distinct spore types ("early" or "primary" and "environmental"). The Vairimorpha life cycle, in addition to a Nosema-type diplokaryotic sporogony, includes an octosporoblastic sporogony producing eight uninucleate spores (octospores) within a sporophorous vesicle.

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Myxobolus pelecicola Voronin et Dudin, 2015 was recently described from the skeletal musculature of sichel Pelecus cultratus. However, another species, Myxobolus ladogensis Rumyantsev et Schulman, 1997, was described previously from the same host, displaying identical tissue localization and spore morphology as in M. pelecicola.

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Chorthippus loratus collected in Krasnodar Territory in 2017 was infected at 15% rate with a microsporidium possessing ovocylindrical binucleate spores, 2.6 × 1.2 μm in size.

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Two species of microsporidia, Nosema apis and Nosema ceranae, occur regularly and cause significant losses in apiculture throughout the world. N. ceranae is thought to be an emerging pathogen of the European honey bee which is replacing N.

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Hexokinase (HK) is a core glycolytic enzyme of Microsporidia which regulates host cell metabolic processes. The goal of the present study was to test for the utility of HK for molecular phylogenetics, species identification and molecular detection of microsporidia in infected insects. HK sequence-based reconstructions were essentially similar to those based upon largest subunit RNA polymerase (RPB1) gene sequences, as well as previously published rRNA gene and genome-based trees.

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An isolate of the microsporidium Vairimorpha ephestiae (originally isolated from Ephestia kühniella) from collection of Prof. J. Weiser was propagated in a laboratory culture of Galleria mellonella.

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Galleria mellonella fed 3 million Nosema pyrausta spores per larva showed 0 and 5% infestation rate at 30 °C and 24 °C, respectively. N. pyrausta virulence did not increase after passage through G.

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Three species of Microsporidia were identified from a population of the beet webworm Loxostege sticticalis at prevalence rates of 35, 4, and 3%. The most prevalent parasite (Tubulinosema sp.) was similar to Tubulinosema acridophagus (99.

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A microsporidium was found in a Mediterranean cricket Gryllus bimaculatus from a pet market in the UK and a lab stock at the Moscow Zoo (originating from London Zoo). The spores were ovoid, uninucleate, 6.3 × 3.

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Ultrastructure of Fibrillaspora is highly similar to that of Berwaldia but the former is phylogenetically distant from the taxon annotated as Berwaldia schaefernai (Genbank accession # AY090042). It was shown recently, however, that the latter sequence was not derived from Berwaldia, and correct nucleotide sequence data were provided for Berwaldia. This allowed recondideration of Fibrillaspora as a junior synonym of Berwaldia and redefinition of Fibrillaspora daphniae as a new combination, Berwaldia daphniae comb.

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Five out of one hundred adults of Niphargogammarus intermedius caught at the Azov sea shore were found to be infected with microsporidia. The infection was found in the subcuticular fat body and myocytes. Parasites developed in direct contact with host cells, displayed a disporoblastic sporogony and diplokaryotic arrangement of nuclei at all stages.

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Paranosema (Nosema, Antonospora) locustae is the only microsporidium produced as a commercial product for biological control. Molecular mechanisms of the effects of this pathogen and other invertebrate microsporidia on host cells remain uncharacterized. Previously, we immunolocalized P.

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Populations of European corn borer (Ostrinia nubilalis Hübner) from Krasnodar Territory (Southwestern Russia) become regularly infected with Nosema-like microsporidia. To identify the parasite, it was subjected to electron microscopy and small subunit ribosomal RNA (SSU rRNA) gene sequencing. The spore ultrastructure of the parasite was highly similar to Nosema bombycis from China and Nosema pyrausta from the USA.

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