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RNA Virus (rna + virus)
Selected AbstractsDetection and analysis of Borna disease virus in Chinese patients with neurological disordersEUROPEAN JOURNAL OF NEUROLOGY, Issue 3 2009Q. Li Background and purpose:, Borna disease virus (BDV) is a neurotropic RNA virus that is known to cause neurological disturbances in various animal species, potentially even humans. However, the association between BDV infection and human neurological disorders remains unclear. Methods:, Between August 2005 and March 2006, 65 patients with neurological disorders were enrolled into our study. The presence of BDV p24 RNA from peripheral blood mononuclear cells (PBMCs) was investigated by using nested reverse transcriptase PCR (RT-PCR) assay. Results:, Borna disease virus p24 RNA was detected from PBMCs in six patients with viral encephalitis by using nested RT-PCR assay. However, BDV p24 RNA was not detected in patients with multiple sclerosis or peripheral nerve diseases. Conclusion:, There might be possible associations between BDV infection and human viral encephalitis. [source] Viral escape mechanisms , escapology taught by virusesINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 5 2001Michaela Lucas Viruses have ,studied' immunology over millions of years of coevolution with their hosts. During this ongoing education they have developed countless mechanisms to escape from the host's immune system. To illustrate the most common strategies of viral immune escape we have focused on two murine models of persistent infection, lymphocytic choriomeningitis virus (LCMV) and murine cytomegalovirus (MCMV).LCMV is a fast replicating small RNA virus with a genome prone to mutations. Therefore, LCMV escapes from the immune system mainly by two strategies: ,speed' and ,shape change'. At the opposite extreme, MCMV is a large, complex DNA virus with a more rigid genome and thus the strategies used by LCMV are no option. However, MCMV has the coding capacity for additional genes which interfere specifically with the immune response of the host. These escape strategies have been described as ,camouflage' and ,sabotage'. Using these simple concepts we describe the spectrum of viral escapology, giving credit not only to the researchers who uncovered this fascinating area of immunology but also to the viruses themselves, who still have a few lessons to teach. [source] A previously unrecognized sixth genotype of GB virus C revealed by analysis of 5,-untranslated region sequencesJOURNAL OF MEDICAL VIROLOGY, Issue 1 2006A. Scott Muerhoff Abstract GB virus C (GBV-C) is a positive-strand RNA virus that infects a large proportion of the world's human population. It has been classified tentatively as a member of the Flaviviridae family and has been shown to exist as a group of five closely related genotypes. Recently, we reported the first full-length genome sequence of a genotype 5 isolate from South Africa [Muerhoff et al. (2005): J Gen Virol 86: 1729,1735]. As part of the analysis of that sequence, a phylogenetic tree was elucidated from the 5,-untranslated region (UTR) that showed excellent congruence to the tree produced by analysis of complete open reading frame sequences. When 5,-UTR analysis was broadened subsequently to include additional isolates from around the globe, a heretofore unrecognized GBV-C genotype was discovered in Indonesia. When first reported in 2000 [Handajani et al. (2000): J Clin Microbiol 38:662,668], these isolates were described as constituting a novel fifth genotype. However, comparison to isolates from the then-known fourth and fifth genotypes (from Myanmar/Vietnam and South Africa, respectively) was not performed. A dataset of 121 GBV-C 5,-UTR sequences was complied and included representatives of the fourth and fifth genotypes as well as the "novel" Indonesian sequences and demonstrated, with strong support via bootstrap analysis, the existence of a sixth GBV-C genotype among infected individuals in Indonesia. The discovery of this sixth genotype emphasizes the diverse nature of GBV-C isolates and may have important implications for the interpretation of studies involving GBV-C/HIV co-infected individuals. J. Med. Virol. 78:105,111, 2006. © 2005 Wiley-Liss, inc. [source] Patterns of Multiple Virus Infections in the Conifer Pathogenic Fungi, Diplodia pinea and Diplodia scrobiculataJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2008Juanita De Wet Abstract Diplodia pinea and Diplodia scrobiculata are opportunistic pathogens associated with various disease symptoms on conifers that most importantly include die-back and stem cankers. Two viruses with dsRNA genomes, Sphaeropsis sapinea RNA virus 1 and 2 (SsRV1 and SsRV2) are found in D. pinea and an undescribed dsRNA element is known to occur in D. scrobiculata. We have partially characterized the putative RNA-dependent RNA polymerase (RdRp) of the undescribed dsRNA element and designed virus-specific primers from the RdRp regions of all three virus genomes. This made it possible to screen for the presence of the three viruses in a collection of D. pinea and D. scrobiculata isolates using real-time PCR. Triple infections with all three viruses occurred in D. pinea and D. scrobiculata. Co-infections with SsRV1 and SsRV2 were common but found only in D. pinea. Co-infection with SsRV1 and the undescribed dsRNA element was rare and observed only in D. pinea. Single infections with either SsRV1 or SsRV2 were equally common, while the undescribed dsRNA element never occurred alone. SsRV1 occurred alone in both D. pinea and D. scrobiculata while SsRV2 occurred alone only in D. pinea. There were only two instances where the undescribed dsRNA element was observed in D. pinea and it was otherwise found only in D. scrobiculata. This study highlights the complex interactions between the viruses found in the closely related plant pathogenic fungi, D. pinea and D. scrobiculata. It illustrates the importance of not only characterizing viruses infecting fungi but also of determining the interactions between mycoviruses and their fungal hosts. [source] Melatonin decreases TLR3-mediated inflammatory factor expression via inhibition of NF-,B activation in respiratory syncytial virus-infected RAW264.7 macrophagesJOURNAL OF PINEAL RESEARCH, Issue 1 2008Sheng-Hai Huang Abstract:, Double-stranded (ds) RNA has been identified as a ligand for Toll-like receptor 3 (TLR3). Respiratory syncytial virus (RSV), a single-stranded RNA virus and a major respiratory pathogen and pneumovirus in human infants pathogenesis of which relies on early inflammatory and immune events of the host in response to RSV, could be recognized by TLR3 sensing viral dsRNA produced during replication. The downstream signaling pathway from TLR3 leads to activation of IFN regulatory factor (IRF)-3 and/or NF-,B and subsequent expression of numerous proinflammatory factors. Melatonin (MT) is an effective regulator of the immune system. To determine the molecular mechanisms responsible for the suppressive effect of MT on RSV infection, we analyzed signaling molecules involved in the TLR3-mediated activation of inflammatory factors in macrophages infected with RSV and the modulatory role of MT on these mediators. We report that RSV infection of RAW264.7 macrophages time-dependently stimulate the rapid activation of TLR3 and NF-,B, as well as subsequent NF-,B-dependent gene expression such as those encoding TNF-, and inducible nitric oxide synthase. Moreover, we demonstrate that MT decreased TLR3-mediated downstream gene expression in RSV-infected macrophages in a dose- and time-dependent manner, and that MT inhibition of NF-,B activity seemed to be the key event required to explain the reduction in inflammatory gene expression caused by MT. But MT did not influence TLR3 at either the protein or mRNA level or MyD88 transcription. These results could be related to the beneficial immunoregulatory role of MT in RSV-infected macrophages and address the possible therapeutic potential of this indoleamine in human RSV diseases. [source] Turnip yellow mosaic virus: transfer RNA mimicry, chloroplasts and a C-rich genomeMOLECULAR PLANT PATHOLOGY, Issue 5 2004THEO W. DREHER SUMMARY Taxonomy:,Turnip yellow mosaic virus (TYMV) is the type species of the genus Tymovirus, family Tymoviridae. TYMV is a positive strand RNA virus of the alphavirus-like supergroup. Physical properties:, Virions are non-enveloped 28-nm T = 3 icosahedrons composed of a single 20-kDa coat protein that is clustered in 20 hexameric and 12 pentameric subunits. Infectious particles and empty capsids coexist in infected tissue. The genomic RNA is 6.3 kb long, with a 5,m7GpppG cap and a 3, untranslated region ending in a tRNA-like structure to which valine can be covalently added. The genome has a distinctive skewed C-rich, G-poor composition (39% C, 17% G). Viral proteins:, Two proteins, whose open reading frames extensively overlap, are translated from the genomic RNA. p206, which contains sequences indicative of RNA capping, NTPase/helicase and polymerase activities, is the only viral protein that is necessary for genome replication in single cells. It is produced as a polyprotein and self-cleaved to yield 141- and 66-kDa proteins. p69 is required for virus movement within the plant and is also a suppressor of gene silencing. The coat protein is expressed from the single subgenomic RNA. Hosts and symptoms:, TYMV has a narrow host range almost completely restricted to the Cruciferae. Experimental host species are Brassica pekinensis (Chinese cabbage) or B. rapa (turnip), in which diffuse chlorotic local lesions and systemic yellow mosaic symptoms appear. Arabidopsis thaliana can also be used. Clumping of chloroplasts and the accumulation of vesicular invaginations of the chloroplast outer membranes are distinctive cytopathological symptoms. High yields of virus are produced in all leaf tissues, and the virus is readily transmissible by mechanical inoculation. Localized transmission by flea beetles may occur in the field. [source] Anti-HCV and HCV-RNA prevalence and clinical correlations in cases with non-Hodgkin's lymphomaAMERICAN JOURNAL OF HEMATOLOGY, Issue 2 2003Semra Paydas Abstract Hepatitis C virus (HCV) is an RNA virus in the Flaviviridae family. It displays lymphotropism in addition to hepatotropism and extrahepatic manifestations are very well known. There are many studies showing an association between HCV infection and non-Hodgkin's lymphomas (NHL). In this study the evidence for HCV infection was studied in cases with NHL. To this end, anti-HCV antibody and HCV-RNA were screened in serum samples of cases with NHL using third-generation ELISA and RT-PCR. Anti-HCV antibody was studied in 223 patients and was found to be positive in 18 cases (8.1%). Anti-HCV antibody positivity was compared with our blood bank / blood donor population. There was an important increased risk of HCV infection,the common odds ratio was 34.56 and corrected odds ratio was 19.07. HCV-RNA was studied in 67 of 223 serum samples. HCV-RNA was found to be positive in 21 of 67 samples (31.3%). When compared with clinico-demographic parameters for anti-HCV and HCV-RNA, including age, nodal status, and grade (in evaluable cases), except age in cases with or without HCV-RNA, we did not find an important correlation with HCV status and clinical findings (P = 0.155; 0.442; 0.288 for anti-HCV and 0.027; 0,558; 0.126, respectively). These results suggest that HCV infection may be an important risk factor for lymphomagenesis and HCV-RNA is more useful for the detection of HCV infection in these immunosuppressed cases. Simultaneous detection of anti-HCV and HCV-RNA will be more informative in this population. Am. J. Hematol. 74:89,93, 2003. © 2003 Wiley-Liss, Inc. [source] Epidemics of Tomato torrado virus, Pepino mosaic virus and Tomato chlorosis virus in tomato crops: do mixed infections contribute to torrado disease epidemiology?ANNALS OF APPLIED BIOLOGY, Issue 3 2010P. Gómez Torrado disease was first observed in protected tomato crops in the Murcia province of Spain in spring 2001, causing serious concern to regional tomato producers. The disease-causing agent was initially identified as a picorna-like bipartite plant RNA virus, now known as Tomato torrado virus (ToTV), but several additional torradoviruses inducing similar disease symptoms have been described more recently. We studied the incidence of torradoviruses between 2005 and 2008 in two parts of Murcia (Spain) where tomato crops are grown commercially. We also analysed the potential association among ToTV, Pepino mosaic virus (PepMV) and Tomato chlorosis virus (ToCV) in samples showing torrado symptoms of varying severity. ToTV was the only torradovirus found in the samples (predominantly as single infections), but double and triple infections comprising ToTV, PepMV and/or ToCV were also detected. There was no evidence of a specific association among the viruses as the frequencies of mixed infections did not deviate from those expected to occur by chance. Statistical analysis of the potential association between torrado symptoms and the type of infection (single or multiple) was inconclusive. To determine whether co-infections with ToTV and PepMV have any marked influence on the torrado disease, we analysed torrado symptom severity and virus accumulation in tomato plants experimentally infected with ToTV-CE, PepMV-Sp13 and PepMV-PS5 in single and mixed infections. The severity of the torrado symptoms was not affected by the presence of PepMV. In single infections, the ToTV titre remained very low, reaching its maximum in the early stages of infection and declining rapidly thereafter, whereas the disease symptoms became more severe over the same timescale. In mixed infections, the accumulation of both ToTV and PepMV was altered with respect to single infections, and the magnitude of this alteration appeared to be virus and strain specific. Therefore, ToTV and PepMV mixed infections may modulate the epidemiology of both viruses in a complex way by altering virus fitness. The impact of our studies on efforts to track and prevent the spread of torrado disease is discussed. [source] Structural genomics of the SARS coronavirus: cloning, expression, crystallization and preliminary crystallographic study of the Nsp9 proteinACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2003Valérie Campanacci The aetiologic agent of the recent epidemics of Severe Acute Respiratory Syndrome (SARS) is a positive-stranded RNA virus (SARS-CoV) belonging to the Coronaviridae family and its genome differs substantially from those of other known coronaviruses. SARS-CoV is transmissible mainly by the respiratory route and to date there is no vaccine and no prophylactic or therapeutic treatments against this agent. A SARS-CoV whole-genome approach has been developed aimed at determining the crystal structure of all of its proteins or domains. These studies are expected to greatly facilitate drug design. The genomes of coronaviruses are between 27 and 31.5,kbp in length, the largest of the known RNA viruses, and encode 20,30 mature proteins. The functions of many of these polypeptides, including the Nsp9,Nsp10 replicase-cleavage products, are still unknown. Here, the cloning, Escherichia coli expression, purification and crystallization of the SARS-CoV Nsp9 protein, the first SARS-CoV protein to be crystallized, are reported. Nsp9 crystals diffract to 2.8,Å resolution and belong to space group P61/522, with unit-cell parameters a = b = 89.7, c = 136.7,Å. With two molecules in the asymmetric unit, the solvent content is 60% (VM = 3.1,Å3,Da,1). [source] Preliminary X-ray data analysis of crystalline hibiscus chlorotic ringspot virusACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 6 2009Ao Cheng Hibiscus chlorotic ringspot virus (HCRSV) is a positive-sense monopartite single-stranded RNA virus that belongs to the Carmovirus genus of the Tombusviridae family, which includes carnation mottle virus (CarMV). The HCRSV virion has a 30,nm diameter icosahedral capsid with T = 3 quasi-symmetry containing 180 copies of a 38,kDa coat protein (CP) and encapsidates a full-length 3.9,kb genomic RNA. Authentic virus was harvested from infected host kenaf leaves and was purified by saturated ammonium sulfate precipitation, sucrose density-gradient centrifugation and anion-exchange chromatography. Virus crystals were grown in multiple conditions; one of the crystals diffracted to 3.2,Å resolution and allowed the collection of a partial data set. The crystal belonged to space group R32, with unit-cell parameters a = b = 336.4, c = 798.5,Å. Packing considerations and rotation-function analysis determined that there were three particles per unit cell, all of which have the same orientation and fixed positions, and resulted in tenfold noncrystallography symmetry for real-space averaging. The crystals used for the structure determination of southern bean mosaic virus (SBMV) have nearly identical characteristics. Together, these findings will greatly aid the high-resolution structure determination of HCRSV. [source] Borna disease virus: a unique pathogen and its interaction with intracellular signalling pathwaysCELLULAR MICROBIOLOGY, Issue 6 2009Oliver Planz Summary Borna disease virus (BDV) is a neurotropic RNA virus that establishes non-cytolytic persistent infection in the central nervous system of warm-blooded animals. Depending on the host species and the route of infection, BDV persistence can modulate neuronal plasticity and animal behaviour and/or may provoke a T cell-mediated immunopathological reaction with high mortality. Therefore, BDV functions as a model pathogen to study persistent virus infection in the central nervous system. Here, we review recent evidence showing that BDV interferes with a spectrum of intracellular signalling pathways, which may be involved in viral spread, maintenance of persistence and modulation of neurotransmitter pathways. [source] | ||||||||||||||||