Search results for "Vesicular Stomatitis"
showing 10 items of 46 documents
Enhanced adaptation of vesicular stomatitis virus in cells infected with vaccinia virus.
2008
Infections involving different viruses (multiple infections) are common in nature and can take place between different strains of the same virus or between different virus species, including DNA and RNA viruses. The influence of multiple infections on viral evolution has been previously studied using different populations of the same virus. Here, we took a step forward by studying the evolution of an RNA virus (vesicular stomatitis virus, VSV) in the presence of a resident DNA virus (vaccinia virus, VV). Cell cultures were infected with a constant amount of VV, and VSV was added at four different post-VV-inoculation times and four different population sizes. The results showed that the pres…
Excessive CpG 1668 stimulation triggers IL-10 production by cDC that inhibits IFN-alpha responses by pDC.
2008
Upon stimulation with a wide range of concentrations of CpG oligodeoxynucleotide 2216 (CpG 2216), plasmacytoid DC are induced to produce type I IFN (IFN-alpha/beta). In contrast, CpG 1668 shows a bell-shaped dose-response correlation, i.e. only intermediate but not high doses of CpG 1668 induce IFN-alpha/beta. Interestingly, high-dose CpG 1668 completely inhibited IFN-alpha responses induced by CpG 2216. Experiments using supernatant of high-dose CpG-1668-treated cells indicated that secreted inhibitor(s) mediated the IFN-alpha shut-off. Among modulating cytokines, IL-10 turned out to be one important negative regulator. In line with this, supernatants of IL-10-deficient DC cultures stimula…
Diminishing Returns of Population Size in the Rate of RNA Virus Adaptation
2000
ABSTRACT Whenever an asexual viral population evolves by adapting to new environmental conditions, beneficial mutations, the ultimate cause of adaptation, are randomly produced and then fixed in the population. The larger the population size and the higher the mutation rate, the more beneficial mutations can be produced per unit time. With the usually high mutation rate of RNA viruses and in a large enough population, several beneficial mutations could arise at the same time but in different genetic backgrounds, and if the virus is asexual, they will never be brought together through recombination. Thus, the best of these genotypes must outcompete each other on their way to fixation. This c…
Enhanced baculovirus-mediated transduction of human cancer cells by tumor-homing peptides.
2006
ABSTRACT Tumor cells and vasculature offer specific targets for the selective delivery of therapeutic genes. To achieve tumor-specific gene transfer, baculovirus tropism was manipulated by viral envelope modification using baculovirus display technology. LyP-1, F3, and CGKRK tumor-homing peptides, originally identified by in vivo screening of phage display libraries, were fused to the transmembrane anchor of vesicular stomatitis virus G protein and displayed on the baculoviral surface. The fusion proteins were successfully incorporated into budded virions, which showed two- to fivefold-improved binding to human breast carcinoma (MDA-MB-435) and hepatocarcinoma (HepG2) cells. The LyP-1 pepti…
Evolution of fitness in experimental populations of vesicular stomatitis virus
1996
Abstract The evolution of fitness in experimental clonal populations of vesicular stomatitis virus (VSV) has been compared under different genetic (fitness of initial clone) and demographic (population dynamics) regimes. In spite of the high genetic heterogeneity among replicates within experiments, there is a clear effect of population dynamics on the evolution of fitness. Those populations that went through strong periodic bottlenecks showed a decreased fitness in competition experiments with wild type. Conversely, mutant populations that were transferred under the dynamics of continuous population expansions increased their fitness when compared with the same wild type. The magnitude of …
Effect of population patchiness and migration rates on the adaptation and divergence of vesicular stomatitis virus quasispecies populations
1999
The effect of migration among different isolated virus quasispecies populations on their adaptation and diversity was analysed through experimental evolution. Anin vitrocell system was employed to simulate migration of vesicular stomatitis virus between isolated homogeneous host cell populations. The results clearly demonstrated a positive correlation between the migration rate and the magnitude of the mean fitness reached by the virus quasispecies populations. The results also showed, although less clearly, that fitness differences among quasispecies decreased with the magnitude of migration. These results are in close agreement with predictions of standard population genetics theory. Thes…
Cost of host radiation in an RNA virus.
2000
Abstract Although host radiation allows a parasite to expand its ecological niche, traits governing the infection of multiple host types can decrease fitness in the original or alternate host environments. Reasons for this reduction in fitness include slower replication due to added genetic material or modifications, fitness trade-offs across host environments, and weaker selection resulting from simultaneous adaptation to multiple habitats. We examined the consequences of host radiation using vesicular stomatitis virus (VSV) and mammalian host cells in tissue culture. Replicate populations of VSV were allowed to evolve for 100 generations on the original host (BHK cells), on either of two …
Contribution of Taq polymerase-induced errors to the estimation of RNA virus diversity.
1998
The genetic diversity of a vesicular stomatitis virus population was analysed by RT-PCR, cloning and sequencing of two approximately 500 nucleotide regions of the virus genome. PCR amplifications were performed in parallel experiments with both Taq and Pfu DNA polymerases, and important differences were observed. Between 10 and 22 mutations were detected when virus populations were analysed by Taq amplification (20 clones from each region), whereas amplification of the same samples with Pfu revealed between 0 and 5 mutations. PCR fidelity assays, performed under the same PCR conditions as those used in the population analysis, showed that the Taq error-rate estimate of 0.27 x 10(-4) misinco…
The distribution of fitness effects caused by single-nucleotide substitutions in an RNA virus.
2004
6 pages, 3 figures.-- PMID: 15159545 [PubMed].-- PMCID: PMC420405.-- Supporting information (Table 3: Relevant information about each single-nucleotide substation mutant created) available at: http://www.pnas.org/content/101/22/8396/suppl/DC1
The contribution of epistasis to the architecture of fitness in an RNA virus
2004
4 pages, 2 figures.-- PMID: 15492220 [PubMed].-- PMCID: PMC524436.-- Additional information (Suppl. table S1: Relevant information about each single- and double-nucleotide substitution mutant created) available at: http://www.pnas.org/content/101/43/15376/suppl/DC1