Search results for "Viruses"
showing 10 items of 1182 documents
Purification and analysis of polyhistidine-tagged human parvovirus B19 VP1 and VP2 expressed in insect cells
2008
Human parvovirus B19 is an autonomously replicating human pathogen with a specific tropism for human erythroid progenitor cells. There is an interest in producing empty nucleocapsids of B19 as they can be used as tools in molecular biology and diagnostics. Native B19 virus particles are formed from two structural viral proteins, VP1 and VP2. The VP2 protein alone is able to self assemble and consequently form virus-like particles (VLPs) in heterologous expression systems. Purification of recombinant VLPs has been conducted using various traditional methods. These include laborious and time-consuming, e.g. cesium chloride or sucrose gradient ultracentrifugation steps, allowing limited workin…
Host-range expansion of Spodoptera exigua multiple nucleopolyhedrovirus to Agrotis segetum larvae when the midgut is bypassed.
2010
Given the high similarity in genome content and organization between Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) and Agrotis segetum nucleopolyhedrovirus (AgseNPV), as well as the high percentages of similarity found between their 30 core genes, the specificity of these NPVs was analysed for the respective insect hosts, S. exigua and A. segetum. The LD(50) for AgseNPV in second-instar A. segetum larvae was 83 occlusion bodies per larva and the LT(50) was 8.1 days. AgseNPV was orally infectious for S. exigua, but the LD(50) was 10 000-fold higher than for SeMNPV. SeMNPV was not infectious for A. segetum larvae when administered orally, but an infection was established by injecti…
6- O - and N -Sulfated Syndecan-1 Promotes Baculovirus Binding and Entry into Mammalian Cells
2013
ABSTRACT Baculoviruses are insect-specific viruses commonly found in nature. They are not able to replicate in mammalian cells but can transduce them when equipped with an appropriate mammalian cell active expression cassette. Although the viruses have been studied in several types of mammalian cells from different origins, the receptor that baculovirus uses to enter or interact with mammalian cells has not yet been identified. Due to the wide tropism of the virus, the receptor has been suggested to be a generally found cell surface molecule. In this article, we investigated the interaction of baculovirus and mammalian cell surface heparan sulfate proteoglycans (HSPG) in more detail. Our da…
Generation of lentivirus vectors using recombinant baculoviruses
2008
In spite of advances in conventional four-plasmid transient transfection methods and development of inducible stable production cell lines, production of replication-defective lentiviral vectors in clinical scale has been challenging. Baculovirus technology offers an alternative to scalable virus production as a result of fast and easy production of baculoviruses, efficient transduction of mammalian cells and safety of the baculoviruses. As a first step toward scalable lentiviral production system, we have constructed four recombinant baculoviruses: the BAC-transfer virus expresses green fluorescent protein (GFP) as a transgene and BAC-gag-pol, BAC-vesicular stomatitis virus glycoprotein G …
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…
Reply to "Heparan Sulfate in Baculovirus Binding and Entry of Mammalian Cells"
2014
(1), we investigated the interaction ofbaculovirus and mammalian cell surface heparan sulfate pro-teoglycans (HSPG). The data show that baculovirus requiresHSPG sulfation, particularly N- and 6-O-sulfation, to bind andtransduce mammalian cells. We also show that baculovirus asso-ciates specifically with syndecan-1 (SDC-1) but not with othersyndecans or glypicans.As discussed in the article, HS has previously been shown to beinvolved in glycoprotein 64 (gp64)-mediated baculovirus bindingonto mammalian cells. Heparin and heparinase I and II treatmentof cells have also been shown to prevent the virus binding (2, 3).The role of HS in baculovirus entry was further studied in ourarticle (1). Bindi…
Novel virocell metabolic potential revealed in agricultural soils by virus-enriched soil metagenome analysis
2021
International audience; Viruses are now recognized as important players in microbial dynamics and biogeochemical cycles in the oceans. Yet, compared with aquatic ecosystems, virus discovery in terrestrial ecosystems has been challenging partly due to the inherent complexity of soils. To expand our understanding of soil viruses and their putative contributions to soil microbial processes, we analysed metagenomes of community-level virus-enriched suspensions by tangential flow filtration obtained from two French agricultural soils. We found viral sequences representing a total of 239 viral operational taxonomic units that corresponded to 29.5% of the mapping reads in the metagenomic datasets.…
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…
Specific binding of radiolabeled Cry1Fa insecticidal protein from Bacillus thuringiensis to midgut sites in lepidopteran species
2012
ABSTRACT Cry1Fa insecticidal protein was successfully radiolabeled with 125 I-Na. Specific binding to brush border membrane vesicles was shown for the lepidopteran species Ostrinia nubilalis , Spodoptera frugiperda , Spodoptera exigua , Helicoverpa armigera , Heliothis virescens , and Plutella xylostella . Homologous competition assays were performed to obtain equilibrium binding parameters ( K d [dissociation constant] and R t [concentration of binding sites]) for these six insect species.
Detection of tick-borne encephalitis virus in I. ricinus ticks collected from autumn migratory birds in Latvia.
2014
Birds have a potential of spreading ticks via bird migration routes. In this study, we screened 170 ticks removed during autumn 2010 from 55 birds belonging to 10 species for the presence of tick-borne encephalitis virus (TBEV). In total, TBEV RNA was detected in 14% of I. ricinus tick samples obtained from different birds species. The results of this study indicate the possible role of migrating birds in the dispersal of TBEV-infected ticks along the southward migration route.