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Analysis of the prevalence rates of the endosymbiotic bacterium of the Wolbachia genus in the populations of corn borers of the Ostrinia genus was carried out. Samples of genomic DNA were extracted from field-collected larvae. The PCR analysis for the presence of Wolbachia infection was performed independently using three diagnostic loci: 16SrRNA, gatB, and fbpA. A positive signal for Wolbachia was obtained for 13.5% of the Ostrinia nubilalis larvae (N = 141) and 31.9% of the Ostrinia scapulalis larvae (N = 138). The infection rate ranged from 2.9% (N = 34) to 65.8% (N = 38) in different geographical populations. At the same time, a significantly higher infection rate of O. scapulalis than O. nubilalis was observed in three out of four habitats. It was also found that the Wolbachia infection was more common for O. scapulalis individuals feeding on hemp than for those collected from mugwort.

A comparison of the small subunit rRNA gene sequences of the microsporidian isolates from corn borers of the Ostrinia genus from Russia and Belarus indicates that they belong to the Nosema pyrausta species. In order to analyze genetic polymorphism, the nucleotide sequences of the molecular clones of the rRNA intergenic spacer (IGS) of the N. pyrausta isolates from Ostrinia nubilalis and Ostrinia scapulalis (Krasnodar territory), as well as from O. nubilalis (Gomel region, Belarus), are determined. Based on the information obtained and available in Genbank, a high level of divergence of the IGS locus between the isolates of different species and populations of microsporidia, as well as between the molecular clones within individual isolates of parasites, is shown.

We evaluated the susceptibility of Galleria mellonella larvae immunosuppressed by the venom of Habrobracon hebetor to soil entomopathogenic ascomycetes with the use of bait method. It was found that the sensitivity of the modified method was significantly (by almost 200 times) increased as compared with the standard procedure, which provided the isolation of fungi when their abundance was extremely low. Envenomated larvae were more susceptible to the entomopathogenic but not saprotrophic fungi. We presented results of isolation of the entomopathogenic fungi from soils in different climatic zones (from the forest tundra to the steppe) using an improved procedure.

The population of the invasive pest of Siberian fir—the four-eyed fir bark beetle Polygraphus proximus Blandf. (FFBB) from Western Siberia was examined for the presence of insect pathogenic ascomycetes. Four species of insect pathogenic fungi, Beauveria bassiana, B. pseudobassiana, Lecanicillium attenuatum, and Isaria farinosa, were detected on the basis of morphological characteristics and/or sequencing data. Bioassays using conidia of fungi B. bassiana and I. farinosa from the ISEA collection were performed against adults of FFBB at different temperatures (5 and 15°C) and 100% RH. The mortality of P. proximus reached 80–100% within 45 days. The fungus B. bassiana was more effective at 15°C as compared to 5°C, whereas I. farinosa was more virulent at 5°C.

After incubation with spores of microsporidia Paranosema spp. during 1—2 h, the quotes of Gryllus spp. haemolymph cells giving positive reaction in histochemical assay for phenoloxidase (PO) activity were significantly lower as compared to the control. Spores of microsporidia P. grylli caused 3- and 5.4-fold decrease of this index in haemocyte monolayers of Gryllus bimaculatus and G. argentinus, respectively. The ability of P. grylli spores to decrease the quote of PO-positive cells in G. bimaculatus haemocyte monolayers was stronger when monolayers and spores had been coincubated for a longer period (2 h) and when the spores used were more fresh (with higher level pf infectivity). Treatment of P. grylli spores with antibiotics resulted in diminishing their ability to decrease the quote of PO-positive cells. The highest level of decrease of this index, being 28.7-fold, was registered when G. bimaculatus haemocytes had been incubated with spores of P. locustae, the highly aggressive parasite which is able to infect orthopteran insect hosts belonging to more than 100 species and to preserve a high level of infectivity for years. Strong correlation has been revealed between infectivity of microsporidian spores and their ability to suppress PO system, which is a key factor in invertebrate immunity.

Microsporidia comprise a group of fungi-related obligate intracellular eukaryotic pathogens with extremely wide host range: from protists to mammals. Adaptation to intracellular parasitism drives these parasites towards significant reduction and modification of the genome and functional apparatus, which causes extreme dependence on the host cell, as well as sophisticated host-parasite relationships. In this review we summarize our results and recent literature data about microsporidian interactions with the host at the cellular level. The impacts of these pathogens to infected cells include induction of hypertrophy, restructuring and modification of the cytoskeleton and the vesicular transport system of the host cells. Microsporidians also able to stimulate the metabolic processes in the infected cells and inhibit their defensive reactions. The main tool of the direct regulatory impact of microsporidia on the host cell apparently is the secretion of the special protein effectors capable to interfere to regulatory and signaling pathways of the host cell.

The beet webworm, Loxostege sticticalis L., is a very dangerous polyphagous insect pest whose outbreaks periodically occur in southern Russia and northern China. The aim of our work was to describe the photoperiodic response of beet webworm populations from western (Krasnodar Territory and Rostov Province) and eastern [Buryatia and China (Hebei Province)] parts of the pest range. The insects were reared under constant photoperiods of 12–18 h and constant temperatures of 19–25°C. Incidence of diapause at different photoperiods did not show any considerable geographic differences, and the critical day length at which 50% of prepupae arrested their development was about 14–15 h in all the populations studied at experimental temperatures. The results obtained agree with the hypothesis on the existence of an area (or areas) where the pest survives during adverse periods and wherefrom it spreads when an outbreak begins (Saulich et al., 1983; Goryshin et al., 1986). Presumably, the larger part of the pest native habitats (to the north of the steppe zone) is occupied by temporary populations, incapable of surviving for long periods without an inflow of migrants from more southerly steppe regions.

Population dynamics of the beet webworm Pyrausta sticticalis L. was studied in 2003–2005 in Krasnodar Territory (Slavyansk-on-Kuban District) during the period of low population density of the pest. In the period examined, the adult death rate was high, fecundity was low; the low rate of hatchability and high rate of mortality was typical of larvae reared in the laboratory. Analysis of life tables has demonstrated that the observed population density of adults could be explained only by a constant flow of migrants. Low viability of insects from the local population could be explained by the infection with pathogenic microorganisms, including viruses of the Polyhedrosis and Granulosi groups of Baculovirus, and microsporidia, including Nosema sticticalis and Microsporidium sp. Reproduction of the pest can also be influenced by unfavorable weather conditions reducing population density in the subsequent generation. It is demonstrated that the model of the beet webworm population density dynamics based on indices of female fertility, changes in the offspring viability, and the rate of infection with microsporidia is more reliable than models based only on meteorological factors.

Cricket haemocytes were derived from either haemolymph or haemopoietic organs (lymph glands) of insects and introduced to a primary culture. Varied isolation protocols, tissue culture vessels, media compositions and cell densities were tested to determine the optimal conditions for in vitro maintenance of haemocytes, and for subsequent light and electron microscopic analysis of monolayers. Freshly prepared Mitsuhashi and Maramorosh (MM;Sigma, Steinheim, Germany) insect medium (420 mOsm), buffered with sodium bicarbonate (pH 7.2) and supplemented with 10 % FCS, was found to be most appropriate for haemocyte maintenance. All tested tissue culture vessels (FLEXiperm units, multiwell plates and Thermanox slides, with the exception of Melineux agar plates), were suitable for cell attachment and haemocyte monolayers formation. Viability of cultured cells was confirmed by LIVE/DEAD Viability/Cytotoxity Kit for Eukaryotic Cells. Free circulating haemocytes were cultivated up to 27 days and then degraded. Infection with the microsporidian Paranosema grylli or the coccidian Adelina grylli caused noticeable swelling of host lymph glands (haemopoietic tissue) and increase in the number of cells comprising the glands. The cells derived from haemopoietic tissue were maintained for maximum 5 days; thereafter multiplication of bacteria normally inhabiting cricket lymph glands destroyed monolayers and killed the cells. Microsporidian and coccidian invasive stages (spores and sporozoites, respectively) were isolated from infected tissues, resuspended in MM medium and added to haemocyte monolayers in ratios 1 zoite per haemocytes or 10 spores per 1 haemocyte. Actively moving zoites contacted and penetrated the cultured cells. Unlike coccidian zoites, microsporidian spores were phagocytized by haemocytes. Application of fluorescent LIVE/DEAD kit allowed to visualize internalized parasites inside host cells as clearly shaped dark areas. The present study has demonstrated that 1) cricket haemocytes from both circulating haemolymph and lymph glands can be short-term cultivated on tissue culture vessel surfaces which made possible their further light and electron microscopic analysis; 2) short-term haemocyte cultures may be employed to study host-parasite interactions, in particular, to follow the initial steps of parasite internalization inside host cell; 3) Fluorescent assay with Viability/Cytotoxity Kit for Eukaryotic Cells (Molecular Probes, Oregon) allows to observe penetration of these parasites into cultured cells.

The thermomechanical properties and heat resistance of fused and cast chrome-corundum refractories, which are distinguished by their increased corrosion resistance to the action of the agressive gaseous medium in the production of glass, were investigated. On the basis of the investigations conducted the service properties of chrome-corundum refractories were determined and recommendations were made for selection of the optimum chemical composition of the fused and cast material in relation to service conditions.

At the present time the structures of the upper parts of tanks in glass furnaces (ports and suspended walls in the flame region in the melting zone and maximum temperatue zones, the arches of the doghouses, etc.) are generally made from fusion-cast baddeleyite-corundum refractories. However, in terms of a whole range of qualitative factors (primarily, resistance to the action of corrosive gaseous medium, enriched:with volatile, components from batch and glass, and thermaX-shoek resistance) these materials in many cases do not meet the severe service conditions in the above parts of the structure [i]. Moreover, their production requires large amounts of scarce, zircon-containing raw materials.

On decrit une methode et un appareillage permettant d'evaluer quantitativement la resistance a la corrosion des refractaires dans l'environnement d'un four de verrerie