Search results for "replica"
showing 10 items of 576 documents
Enhancing the multiplication of nucleopolyhedrovirus in vitro by manipulation of the pH
2009
Insect nucleopolyhedroviruses (NPVs) are studied widely as agents for biological control, as expression vectors for the production of heterologous proteins, and as transduction vectors for gene therapy applications. Most of these applications rely on the existence of cell lines that allow in vitro multiplication of the virus. The influence of pH in the medium culture on the multiplication of SeMNPV, HearSNPV and AcMNPV in different cell culture lines was investigated. The study showed a strong influence of the medium pH on the virus multiplication with the best results at pH 6.5, about half pH unit above the pH of insect culture media used most commonly. Additional experiments using a recom…
N-acetyl-L-cysteine (NAC) inhibit mucin synthesis and pro-inflammatory mediators in alveolar type II epithelial cells infected with influenza virus A…
2011
64% of chronic obstructive pulmonary disease (COPD) exacerbations are caused by respiratory infections including influenza (strains A and B) and respiratory syncytial virus (RSV). They affect the airway epithelium increasing inflammatory and apoptosis events through mechanisms involving ROS generation, and induce the release of mucins from epithelial cells that are involved in the deterioration of the patient's health during the course of the disease. The antioxidant NAC has proved useful in the management of COPD reducing symptoms, exacerbations and accelerated lung function decline. It has been shown to inhibit influenza virus replication and to diminish the release of inflammatory and ap…
Reconstitution of CD8 T cells is essential for the prevention of multiple-organ cytomegalovirus histopathology after bone marrow transplantation.
1998
Cytomegalovirus (CMV) infection in the period of temporary immunodeficiency after haematoablative treatment and bone marrow transplantation (BMT) is associated with a risk of graft failure and multiple-organ CMV disease. The efficacy of immune system reconstitution is decisive for the prevention of CMV pathogenesis after BMT. Previous data in murine model systems have documented a redundancy in the immune effector mechanisms controlling CMV. CD8 T cells proved to be relevant but not irreplaceable as antiviral effectors. Specifically, in a state of long-term in vivo depletion of the CD8 T-cell subset, CD4 T cells were educed to become deputy effectors controlling CMV by a mechanism involving…
Oral delivery of homologous and heterologous strains of rotavirus to BALB/c mice induces the same profile of cytokine production by spleen cells.
1998
Abstract In this work, we wanted to clarify if differences in antibody (Ab) and particularly in secretory immunoglobulin A (IgA) responses following homologous or heterologous rotavirus infection could be explained by different priming of specific T helper (Th) cells. We compared the Ab responses from suckling BALB/c mice orally inoculated with either a heterologous simian (SA11) or bovine (RF) rotavirus or a homologous murine rotavirus (EHP w ), as well as the profile of cytokines produced by spleen cells after in vitro restimulation. Oral inoculation of EHP w and SA11 induced a similar pattern of Ab with mucosal and serum IgA associated with serum IgG with equal levels of IgG1 and IgG2a, …
Repetitive nucleotide sequencing of a dispensable DNA segment in a clonal population of African swine fever virus
1991
Abstract Repetitive nucleotide sequencing of a dispensable genomic segment of a clonal population of African swine fever (ASF) virus has been carried out to estimate the mutant frequency to neutral alleles. Since no mutations have been detected in a total of 54026 nucleotides screened, the maximum mutant frequency is 5.5 × 10 −5 substitutions/nucleotide (95% confidence level). The result renders very unlikely the occurrence of hypermutational events during ASF virus DNA replication, at least within the selected DNA fragment.
The effect of genetic complementation on the fitness and diversity of viruses spreading as collective infectious units
2019
Viruses can spread collectively using different types of structures such as extracellular vesicles, virion aggregates, polyploid capsids, occlusion bodies, and even cells that accumulate virions at their surface, such as bacteria and dendritic cells. Despite the mounting evidence for collective spread, its implications for viral fitness and diversity remain poorly understood. It has been postulated that, by increasing the cellular multiplicity of infection, collective spread could enable mutually beneficial interactions among different viral genetic variants. One such interaction is genetic complementation, whereby deleterious mutations carried by different genomes are compensated. Here, we…
Effective infection, apoptotic cell killing and gene transfer of human hepatoma cells but not primary hepatocytes by parvovirus H1 and derived vector…
2001
Autonomous parvoviruses preferentially replicate in and kill in vitro–transformed cells and reduce the incidence of spontaneous and implanted tumors in animals. Because of these natural oncotropic and oncolytic properties, parvoviruses deserve to be considered as potential antitumor vectors. Here, we assessed whether parvovirus H1 is able to kill human hepatoma cells by induction of apoptosis but spares primary human liver cells, and whether the former cells can efficiently be transduced by H1 virus–based vectors. Cell death, infectivity, and transgene transduction were investigated in Hep3B, HepG2, and Huh7 cells and in primary human hepatocytes with natural and recombinant H1 virus. All h…
Ub surprised: viral ovarian tumor domain proteases remove ubiquitin and ISG15 conjugates.
2007
Ubiquitin (Ub) and interferon stimulated gene product 15 (ISG15) reversibly conjugate to proteins via a conserved LRLRGG C-terminal motif, mediating important innate antiviral responses. The ovarian tumor (OTU) domain represents a superfamily of predicted proteases found in eukaryotic, bacterial and viral proteins, some of which have Ub-deconjugating activity. We show that the OTU domain-containing proteases of nairoviruses and arteriviruses hydrolyze Ub and ISG15 from cellular target proteins. This broad activity contrasts with the target specificity of known mammalian OTU domain-containing proteins. The biological significance of this activity of viral OTU domain-containing proteases was …
Oncolytic parvovirus H1 induces release of heat-shock protein HSP72 in susceptible human tumor cells but may not affect primary immune cells.
2003
Certain autonomous parvoviruses preferentially replicate in and kill in vitro-transformed cells and may reduce the incidence of spontaneous and implanted tumors in animals. Hence, these viruses and their derivatives are currently under evaluation as antitumor vectors. However, the mechanisms underlying their tumor-suppressing properties are not yet understood. We asked whether the lytic parvovirus H1 may enhance the immunogenicity of infected tumor cells. Out of human melanoma and gastrointestinal tumor cells, we selected the cell line SK29-Mel-1 being very susceptible to H1-induced apoptotic killing. Here, no upregulation of HLA class I and costimulatory molecules could be observed followi…
Subcellular localization of bacteriophage PRD1 proteins in Escherichia coli
2014
Bacteria possess an intricate internal organization resembling that of the eukaryotes. The complexity is especially prominent at the bacterial cell poles, which are also known to be the preferable sites for some bacteriophages to infect. Bacteriophage PRD1 is a well-known model serving as an ideal system to study structures and functions of icosahedral internal membrane-containing viruses. Our aim was to analyze the localization and interactions of individual PRD1 proteins in its native host Escherichia coli. This was accomplished by constructing a vector library for production of fluorescent fusion proteins. Analysis of solubility and multimericity of the fusion proteins, as well as their …