Search results for "Virology"
showing 10 items of 2354 documents
C7(P32) and C6(P34) PR proteins induced in tomato leaves by citrus exocortis viroid infection are chitinases
1990
[EN] Two chitinases induced in tomato leaves (Lycopersicon esculentum Mill cv. Rutgers) by citrus exocortis viroid (CEV) infection were purified. Their molecular masses determined by sodium dodecyl sulfate-gel electrophoresis were 32 kDa and 34 kDa and by filtration through Sephadex G-100 were 23 kDa and 25 kDa, respectively. These chitinases (P32 and P34) have been shown to be identical to the tomato pathogenesis-related proteins C7 and C6. They were purified in three stages: ammonium sulphate fractionation, chitin affinity chromatography and CM-Sepharose chromatography. The characterization of P32, the major component of the CEV-induced chitinase activity, revealed a basic protein (pI, 8·…
Analysis of myxoma virus genome using pulsed-field gel electrophoresis
1996
A method is presented for the isolation of large quantities of myxoma virus DNA using pulsed-field gel electrophoresis (PFGE), and some preliminary applications of this technique.
Sequential variation in genomic RNA patterns of human rotaviruses isolated from infantile gastroenteritis
1986
The incidence and RNA electrophoretypes of rotaviral isolates obtained from infants and young children with acute gastroenteritis were studied from October, 1985 through April, 1986. Analysis of the viral RNA was carried out by Polyacrylamide gel electrophoresis followed by silver staining. Fourteen electrophoretypes were identified. A single dominant electrophoretype was found during the first months of the rotavirus seasonal outbreak. In contrast, a large variety of RNA patterns were observed during the latter portion of the study period. Subgrouping of rotavirus isolates by a double-sandwich enzyme-linked immunosorbent assay using monoclonal-detecting antibodies showed that all strains b…
Promoter-Targeted Histone Acetylation of Chromatinized Parvoviral Genome Is Essential for the Progress of Infection
2015
ABSTRACT The association of host histones with parvoviral DNA is poorly understood. We analyzed the chromatinization and histone acetylation of canine parvovirus DNA during infection by confocal imaging and in situ proximity ligation assay combined with chromatin immunoprecipitation and high-throughput sequencing. We found that during late infection, parvovirus replication bodies were rich in histones bearing modifications characteristic of transcriptionally active chromatin, i.e., histone H3 lysine 27 acetylation (H3K27ac). H3K27ac, in particular, was located in close proximity to the viral DNA-binding protein NS1. Importantly, our results show for the first time that in the chromatinized …
Development and characterization of a 293 cell line with regulatable expression of the hepatitis B virus large envelope protein
2004
During the life cycle of hepatitis B virus (HBV) the large L envelope protein plays a pivotal role that is related to its peculiar dual transmembrane topology. To study the complex structure and diverse functions of L under regulated conditions of production, a human 293 cell line stably expressing L under the control of the ecdysone-inducible promoter was generated. Cells demonstrated stringent dose- and time-dependent kinetics of induction with undetectable background expression in the absence of the inducer. Temporal control of L expression allowed to trace (i) its posttranslational reorientation resulting in the mixed topology; (ii) its spatial redistribution from the endoplasmic reticu…
Posttranslational N-glycosylation of the hepatitis B virus large envelope protein
2007
Abstract Background The addition of N-linked glycans to proteins is normally a cotranslational process that occurs during translocation of the nascent protein to the endoplasmic reticulum. Here, we report on an exception to this rule occurring on the hepatitis B virus (HBV) large L envelope protein that is a subject to co-plus posttranslational N-glycosylation. Results By using an improved detection system, we identified so far unrecognized, novel isoforms of L. Based on mutational analyses, the use of N-glycosylation inhibitors, and pulse-chase studies, we showed that these isoforms are due to posttranslational N-glycan addition to the asparagines 4 and 112 within the preS domain of L. Whi…
Role for Tumor Necrosis Factor Alpha in Murine Cytomegalovirus Transcriptional Reactivation in Latently Infected Lungs
2004
ABSTRACT Interstitial pneumonia is a major clinical manifestation of primary or recurrent cytomegalovirus (CMV) infection in immunocompromised recipients of a bone marrow transplant. In a murine model, lungs were identified as a prominent site of CMV latency and recurrence. Pulmonary latency of murine CMV is characterized by high viral genome burden and a low incidence of variegated immediate-early (IE) gene expression, reflecting a sporadic activity of the major IE promoters (MIEPs) and enhancer. The enhancer-flanking promoters MIEP1/3 and MIEP2 are switched on and off during latency in a ratio of ∼2:1. MIEP1/3 latency-associated activity generates the IE1 transcript of the ie1/3 transcrip…
Cytomegalovirus Interleukin-10 Expression in Infected Cells Does Not Impair MHC Class I Restricted Peptide Presentation on Bystanding Antigen-Present…
2006
Human cytomegalovirus (HCMV) has evolved strategies to counteract its surveillance by the immune system. Mitigation of antiviral immune responses is considered critical for establishment of viral latency and for spread. Recently, a gene encoding an interleukin-10 homologue (cmvIL-10) has been discovered in the HCMV genome. Using recombinant cmvIL-10, several mostly immunosuppressive functions of the molecule have been described. However, the role of cmvIL-10 in the context of viral infection was not addressed. To be able to analyze this issue, we generated cmvIL- 10-negative viral mutants. Using these mutants, we tested whether the expression of cmvIL-10 by infected cells would render bysta…
Enhancerless Cytomegalovirus Is Capable of Establishing a Low-Level Maintenance Infection in Severely Immunodeficient Host Tissues but Fails in Expon…
2010
ABSTRACT Major immediate-early transcriptional enhancers are genetic control elements that act, through docking with host transcription factors, as a decisive regulatory unit for efficient initiation of the productive virus cycle. Animal models are required for studying the function of enhancers paradigmatically in host organs. Here, we have sought to quantitatively assess the establishment, maintenance, and level of in vivo growth of enhancerless mutants of murine cytomegalovirus in comparison with those of an enhancer-bearing counterpart in models of the immunocompromised or immunologically immature host. Evidence is presented showing that enhancerless viruses are capable of forming restr…
Relationships among porcine and human P[6] rotaviruses: Evidence that the different human P[6] lineages have originated from multiple interspecies tr…
2005
AbstractPorcine rotavirus strains (PoRVs) bearing human-like VP4 P[6] gene alleles were identified. Genetic characterization with either PCR genotyping or sequence analysis allowed to determine the VP7 specificity of the PoRVs as G3, G4, G5 and G9, and the VP6 as genogroup I, that is predictive of a subgroup I specificity. Sequence analysis of the VP8* trypsin-cleavage product of VP4 allowed PoRVs to be characterized further into genetic lineages within the P[6] genotype. Unexpectedly, the strains displayed significantly higher similarity (up to 94.6% and 92.5% at aa and nt level, respectively) to human M37-like P[6] strains (lineage I), serologically classifiable as P2A, or to the atypical…