A New Picornavirus Isolated from Bank Voles (Clethrionomys glareolus)

AbstractA previously unknown picornavirus was isolated from bank voles (Clethrionomys glareolus). Electron microscopy images and sequence data of the prototype isolate, named Ljungan virus, showed that it is a picornavirus. The amino acid sequences of predicted Ljungan virus capsid proteins VP2 and VP3 were closely related to the human pathogen echovirus 22 (approximately 70% similarity). A partial 5′ noncoding region sequence of Ljungan virus showed the highest degree of relatedness to cardioviruses. Two additional isolates were serologically and molecularly related to the prototype

The role of lipid droplets in the emergence of diabetes mellitus type 2

The increased incidence of diabetes mellitus type 2 (DM2T) all over the world and in Russia in particular, indicates a lack of effectiveness of antidiabetic therapy and suggests the existence of gaps in the understanding of the mechanisms of onset and clinical course of this disease as well as a concomitant lack of effectiveness of antidiabetic therapy. It is known that metabolic disorders that cause DM2T are caused by disturbances in mitochondrial activity resulting in increased cellular fatty acid inclusions and insulin resistance. The present review presents the current state of knowledge about new cellular structures, fat inclusions or, using a more conventional term, lipid droplets (LDs), as a pathological feature accompanying the occurrence of DM2T. The review describes the biochemical and functional characteristics of LDs and their possible role in the onset and development of diabetes. The interrelationship of LDs and mitochondria and the effect of LDs on the nervous system are considered. Particular attention is paid to highlighting the effect of the microbiota of the gastrointestinal tract on the dynamics of the emergence of LDs. The GIT microbiota plays an important role in the development and course of many human diseases associated with metabolic disorders. Further knowledge of the relationship between the gastrointestinal microbiota and the dynamics of LD emergence will uncover new aspects of the molecular mechanism of mitochondrial function, which gives the prospect of preventive approaches in the treatment of obesity, metabolic disorders and diabetes

A liquid-crystalline hexagonal columnar phase in highly-dilute suspensions of imogolite nanotubes

International audienceLiquid crystals have found wide applications in many fields ranging from detergents to information displays and they are also increasingly being used in the 'bottom-up' self-assembly approach of material nano-structuration. Moreover, liquid-crystalline organizations are frequently observed by biologists. Here we show that one of the four major lyotropic liquid-crystal phases, the columnar one, is much more stable on dilution than reported so far in literature. Indeed, aqueous suspensions of imogolite nanotubes, at low ionic strength, display the columnar liquid-crystal phase at volume fractions as low as B0.2%. Consequently, due to its low visco-elasticity, this columnar phase is easily aligned in an alternating current electric field, in contrast with usual columnar liquid-crystal phases. These findings should have important implications for the statistical physics of the suspensions of charged rods and could also be exploited in materials science to prepare ordered nanocomposites and in biophysics to better understand solutions of rod-like biopolymers

Analysis of the Microbiome of Human Lungs and Respiratory System in Lung Disorders: a Review

Микробиота легочной системы способна оказывать значимое влияние на стабильность структуры и функциональную активность легких. Инициация и прогрессирование некоторых заболеваний легких зависит от патогенных факторов, экспрессируемых легочной микробиотой, и состояния дисбиоза в целом. Метагеномные исследования, основанные на секвенировании генов 16S рРНК, позволили получить актуальные данные о составе легочной микробиоты. Гены 16S рРНК состоят из 9 вариабельных участков (V1- V9). Определение более консервативных в эволюционном плане участков последовательностей 16S рРНК гена позволяет относить исследуемые геномы бактерий к таксонам более высокого порядка, в то время как получение информации о менее консервативных участках позволяет определять принадлежность бактерий к роду или виду. В настоящее время также активно развивается метатранскриптомика, основанная на оценке числа копий транскриптов легочной микробиоты. Существование разнообразия и избыточности генов, а также вариабельность их активности в разных условиях предполагает использование таких высокопроизводительных технологий, как секвенирование РНК и методы параллельного секвенирования. Полученные данные по метатранскриптомному анализу в значительной степени дополняют результаты метагеномных исследований, в то же время предполагается, что метатранскриптомный подход более информативен, что касается исследований функциональных взаимодействий между микробиотой и организмом-хозяином. Эти подходы предполагают оценку биологической активности различных компонентов микробиома в норме и патологии. В обзоре рассмотрены методические особенности применения метагеномного анализа, а также метатранскриптомных исследований при некоторых тяжелых заболеваниях легочной системы (рак легкого, хроническая обструктивная болезнь легких, астма и муковисцидоз)The structural stability of the respiratory system and the functional activity of the lungs are influenced by the local microflora. The initiation and the progression of some lung diseases are determined by pathogenic factors produced by the lung microbiota and the dysbiotic conditions in general. Metagenomic studies based on sequencing of the genes for 16S ribosomal RNA have been used to collect direct data on the composition of the lung microbiota. 16S rRNA genes consist of 9 variable regions (V1-V9). By determining highly conservative 16S rRNA regions, bacterial genomes can be assigned to higher-level taxa, while based on information about less conservative regions of these genes, the genera or species of bacteria can be identified. Metatranscriptomics, which is based on estimating the number of copies of transcripts from the pulmonary microbiota, is also rapidly developing. The diversity and redundancy of genes and their variable activity in different conditions are prerequisites for using high-performance technologies such as RNA‑seq and parallel sequencing methods. The metatranscriptomic analysis data significantly complement metagenomics; at the same time, metatranscriptomics is assumed to be more informative in examination of functional interactions between microbiome and host organism. These approaches offer an estimation of the biological activity of different components in the microbiome under normal and pathological conditions. This review summarizes the results of recent metagenomic and metatranscriptomic studies regarding a number of serious diseases of the respiratory system (lung cancer, chronic obstructive lung disease, asthma, and cystic fibrosis

Approche multi-échelle pour la caractérisation de l'espace poreux des réservoirs pétroliers argileux non conventionnels

Gas shale reservoirs are characterized by pore systems, associated with a heterogeneous spatial distribution of mineral and organic phases at multiple scales. This high heterogeneity requires a multi-scale & multi-tool approach to characterize the pore network. Such an approach has been developed on 7 cores from the Vaca Muerta formation (Argentina), which belong to areas with various hydrocarbon maturities, but with comparable mineral compositions. 3D µtomography and quantitative 2D mapping of the connected porosity by autoradiography have been applied at the core scale, in aim to localize and analyze the spatial heterogeneities, and to identify similar homogenous areas for localizing comparable sub-samples.The correlative coupling of various techniques was applied to achieve quantitative balance of porosity and pore size distribution, from mm to nm scales on representative sub-samples and for the first time, on preserved blocks rather than crushed powders, even for nitrogen gas adsorption experiments. Results of autoradiography are in very good agreement with other total bulk porosities, indicating that all pores are connected and accessed by the 14C-MMA used for impregnation. Decreased total porosity and pore throat/body sizes were also observed as organic matter maturity increased. An innovative approach for electron microscopy images acquisition and treatment provided large mosaics, with the distribution of mineral and organic phases at the cm scale. The correlative coupling with the autoradiography porosity map of the same zone, revealed the spatial correlations between mineralogical variations and porosity.Les réservoirs pétroliers argileux sont caractérisés par des systèmes de pores associés à une distribution spatiale hétérogène à plusieurs échelles des phases minérales et organiques. Cette hétérogénéité nécessite une approche multi-échelle et multi-outils pour caractériser le réseau de pores. Une telle approche a été développée grâce à la sélection rigoureuse de 7 carottes issues de la formation de Vaca Muerta (Argentine), avec différentes maturations d'hydrocarbures mais des compositions minérales comparables. La tomographie RX 3D et la cartographie de la porosité par autoradiographie ont révélé les hétérogénéités à l'échelle des carottes, et permis d'identifier des zones homogènes pour le prélèvement de sous-échantillons comparables et représentatifs.Le couplage corrélatif de différentes techniques a permis d'atteindre un bilan quantitatif de la porosité / tailles de pores et pour la première fois, sur des blocs non broyées, notamment pour les expériences d'adsorption d'azote. Les résultats d’autoradiographie sont en accord avec les autres méthodes, indiquant que tous les pores sont connectés et accessibles par la résine d’imprégnation. Une diminution de la porosité totale ainsi que des tailles de pores a également été observée avec la maturation de la matière organique.Une approche innovante pour l'acquisition et le traitement de mosaïques d’images MEB a fourni des cartographies de la distribution des phases minérales et organiques à l'échelle du cm. Le couplage corrélatif avec la carte de porosité par autoradiographie des mêmes zones, a révélé les corrélations spatiales entre variations minéralogiques et de porosité

Multiscale approach for the pore space characterization of gas shales

Les réservoirs pétroliers argileux sont caractérisés par des systèmes de pores associés à une distribution spatiale hétérogène à plusieurs échelles des phases minérales et organiques. Cette hétérogénéité nécessite une approche multi-échelle et multi-outils pour caractériser le réseau de pores. Une telle approche a été développée grâce à la sélection rigoureuse de 7 carottes issues de la formation de Vaca Muerta (Argentine), avec différentes maturations d'hydrocarbures mais des compositions minérales comparables. La tomographie RX 3D et la cartographie de la porosité par autoradiographie ont révélé les hétérogénéités à l'échelle des carottes, et permis d'identifier des zones homogènes pour le prélèvement de sous-échantillons comparables et représentatifs.Le couplage corrélatif de différentes techniques a permis d'atteindre un bilan quantitatif de la porosité / tailles de pores et pour la première fois, sur des blocs non broyées, notamment pour les expériences d'adsorption d'azote. Les résultats d’autoradiographie sont en accord avec les autres méthodes, indiquant que tous les pores sont connectés et accessibles par la résine d’imprégnation. Une diminution de la porosité totale ainsi que des tailles de pores a également été observée avec la maturation de la matière organique.Une approche innovante pour l'acquisition et le traitement de mosaïques d’images MEB a fourni des cartographies de la distribution des phases minérales et organiques à l'échelle du cm. Le couplage corrélatif avec la carte de porosité par autoradiographie des mêmes zones, a révélé les corrélations spatiales entre variations minéralogiques et de porosité.Gas shale reservoirs are characterized by pore systems, associated with a heterogeneous spatial distribution of mineral and organic phases at multiple scales. This high heterogeneity requires a multi-scale & multi-tool approach to characterize the pore network. Such an approach has been developed on 7 cores from the Vaca Muerta formation (Argentina), which belong to areas with various hydrocarbon maturities, but with comparable mineral compositions. 3D µtomography and quantitative 2D mapping of the connected porosity by autoradiography have been applied at the core scale, in aim to localize and analyze the spatial heterogeneities, and to identify similar homogenous areas for localizing comparable sub-samples.The correlative coupling of various techniques was applied to achieve quantitative balance of porosity and pore size distribution, from mm to nm scales on representative sub-samples and for the first time, on preserved blocks rather than crushed powders, even for nitrogen gas adsorption experiments. Results of autoradiography are in very good agreement with other total bulk porosities, indicating that all pores are connected and accessed by the 14C-MMA used for impregnation. Decreased total porosity and pore throat/body sizes were also observed as organic matter maturity increased. An innovative approach for electron microscopy images acquisition and treatment provided large mosaics, with the distribution of mineral and organic phases at the cm scale. The correlative coupling with the autoradiography porosity map of the same zone, revealed the spatial correlations between mineralogical variations and porosity

EBV membrane protein LMP2A interactions with ubiquitin ligases and a signaling scaffold

Over 90% of the adult human population carries Epstein-Barr Virus (EBV). EBV stays for life, striking a balance with the immune system. The virus evades immune elimination by severely restricting its own gene expression. The latent infection is established with the resting memory type B-cell as the reservoir. In the majority of infected individuals worldwide the coexistence with EBV is harmless. The dependence on a functioning immune system is clearly borne out by the long list of EBV-associated diseases that also feature accompanying immune dysfunction. An RNA message for the Latent Membrane Protein 2A (LMP2A) of EBV is constantly detected both in peripheral B-cells of healthy EBV carriers and in EBVassociated tumors. Elucidation of LMP2A interactions with the host cell will therefore contribute both to a better understanding of cellular signaling pathways, the regulation of EBV latency and to treatment of EBV-associated malignancies. Years of LMP2A research lead to the conclusion that LMP2A serves as a safeguard for the latency of EBV in the resting memory type B cells by interfering with and intercepting B-Cell Receptor (BCR) functions. In the normal resting B cell, BCR provides tonic signals to promote cell survival until the B-cell encounters its cognate antigen, upon which antigen-induced BCR signals will initiate differentiation to antibody-producing plasma cells. LMP2A sends surrogate tonic survival signals but interferes with the antigen-induced signals from the BCR. It does so by activating a key survival molecule in the cell, the serine-threonine kinase Akt and by down-regulating the Src-family tyrosine kinase Lyn, which is essential for antigen driven B-cell activation and differentiation. This knowledge about the functions of LMP2A was gained by using in-vitro cultured cells, biochemical and reverse genetic methods, as were the present studies, since the in-vivo cells that harbor the latent EBV infection are so scarce that direct studies can not be performed. Studies of viral perturbation of cellular systems are relevant model systems for learning about the normal functions of the cell and for pointing to vulnerable functions that are targeted also in non-viral disease, as in cancer. In the present thesis I provide evidence that: 1. Activation of LMP2A by constitutive tyrosine phosphorylation requires clustering of LMP2A molecules in the raft compartments of cell membranes (Paper I). 2. Src-family kinases, normally associated with the BCR, are labeled for degradation by E3 ubiquitin ligases of the Nedd4/AIP4 HECT-domain family, which are bound to LMP2A (Paper II); 3. LMP2A interacts with the Shb signaling scaffold, which can mediate Akt activation (Paper III)

P11

In vitro Epstein-Barr virus (EBV) infects B-cells resulting in immortalization, In vivo the virus resides latent in resting B-cells. Rarely the EBV-host cell interaction may contribute to development of malignant lymphoma. It is well known that both c-myc translocation and the viral infection are observed in patients with EBV+ Burkitt’s lymphoma (BL). Proteoglycans (PGs) are complex glycosylated proteins. They are key components of ECM and play a critical role in cell–cell and cell–matrix interactions. Disruptions of such interactions will affect B cell interaction with surrounding stroma and may thus perturb the cell phenotypes. The purpose of this study was to investigate expressinon of proteoglycans in EBV+ cell lines with different origins and phenotypes. We analysed the expression of 12 of the main proteoglycans in primary B cells, lymphoblastoid cell lines (LCLs) generated by EBV infection of normal human B cells in vitro and EBV-positive BL cell lines. An EBV-negative BL cell line was used for reference. According to RT-PCR analysis, primary B-lymphocytes expressed different PGs, mainly serglycin, CD44, perlecan and syndecan-1. The high expression of PGs in normal B cells probably reflects interactions of these cells with the neighbouring cells and microenvironment. B cell lines which carry EBV, in general, showed lower levels of PGs. The PGs expression pattern was similar in LCLs and in primary B cells, however, distinguished by high levels of perlecan and serglycin and low expression of CD44 in LCLs. BL cells showed the most significant down-regulation of PGs compared to primary B cells. There was a correlation between the type of EBV latency program, and PGs expression. Serglycin was expressed at a low levels in BL-cells with EBV latency III-program compared to LCLs, while in EBV latency I BL cells both serglycin and perlecan were down-regulated. Cells with latency I-program show general hypermethylation of the cellular genome in contrast to cells with latency III-program. Thus we explored the possibility of epigenetic regulation of the PG-coding genes by treating cells with 5′-deoxyazacytidine (5-AzaC, a demethylating agent) and Trichostatin A (TSA, a chromatin structure modulator). There was no significant change in PGs expression upon this treatment in LCLs or in EBV latency III BL cells, while EBV latency I BL cells showed up-regulation of several PGs. This suggests that PGs expression is at least partly regulated by epigenetic mechanisms. Interestingly EBV latency is also partly regulated at the epigenetic level. Similar trends were observed for the key ECM components (collagen 1A1, fibronectin and elastin). Normal B lymphocytes expressed collagen, fibronectin and elastin, whereas LCLs and BL cells showed no expression of these. Treatment of these cells with 5-AzaC or TSA resulted in similar changes in PGs expression patterns. Up-regulation of ECM components was detected only in EBV latency I BL cells. Taken together, our data show that proteoglycans are expressed in primary B lymphocytes whereas they are not or only partly expressed in EBV-carrying cell lines, depending on their latency program. Expression of PGs in latency I BL cells is silenced due to hypermethylation, but by another mechanim in latency III BL cells. These results show that PGs expression patterns follow the EBV latency programs . It will be highly interesting to further investigate if EBV and its transformation associated genes are directly involved in control of PGs, as well as how PGs may contribute to major phenotypic properties of EBV-carrying cell lines, such as adhesion, migration and growth in soft agarose – a property associated with the malignant phenotype of BLs