Search results for "Viruses"
showing 10 items of 1182 documents
Association of human herpesvirus 6 and human herpesvirus 7 with demyelinating diseases of the nervous system.
2001
Peripheral blood mononuclear cells and plasma of 113 patients with neurological disorders and 150 blood donors were analyzed for HHV-6 and HHV-7 sequences by PCR. The prevalence of HHV-6 was significantly higher in patients with multiple sclerosis (P < 0.01) than in cases of nondemyelinating diseases of the central and demyelinating diseases of the peripheral nervous systems and blood donors. HHV-6 viremia was found only in patients with multiple sclerosis, predominantly in the active phase of the disease. A significantly higher frequency of HHV-7 reactivation in patients with demyelinating diseases of the peripheral nervous system suggests also its association with demyelinating processes.
Non-local multiscale approach for the impact of go or grow hypothesis on tumour-viruses interactions
2021
International audience; We propose and study computationally a novel non-local multiscale moving boundary mathematical model for tumour and oncolytic virus (OV) interactions when we consider the go or grow hypothesis for cancer dynamics. This spatio-temporal model focuses on two cancer cell phenotypes that can be infected with the OV or remain uninfected, and which can either move in response to the extracellular-matrix (ECM) density or proliferate. The interactions between cancer cells, those among cancer cells and ECM, and those among cells and OV occur at the macroscale. At the micro-scale, we focus on the interactions between cells and matrix degrading enzymes (MDEs) that impact the mov…
A Sliding Window-Based Method to Detect Selective Constraints in Protein-Coding Genes and Its Application to RNA Viruses
2002
Here we present a new sliding window-based method specially designed to detect selective constraints in specific regions of a multiple protein-coding sequence alignment. In contrast to previous window-based procedures, our method is based on a nonarbitrary statistical approach to find the appropriate codon-window size to test deviations of synonymous (d(S)) and nonsynonymous (d(N)) nucleotide substitutions from the expectation. The probabilities of d(N) and d(S) are obtained from simulated data and used to detect significant deviations of d(N) and d(S) in a specific window region of the real sequence alignment. The nonsynonymous-to-synonymous rate ratio (w = d(N)/d(S)) was used to highlight…
Genetic variability and evolutionary analysis of parietaria mottle virus: role of selection and genetic exchange
2015
[EN] The genetic variability and evolution of parietaria mottle virus (PMoV) of the genus Ilarvirus was studied by analyzing nucleotide sequences of 2b and CP genes from isolates collected in different countries. Phylogenetic analysis showed that PMoV isolates clustered in different clades: one (clade I) composed of only Italian isolates and three clades (clades II-IV) including the Spanish isolates. The Greek isolate GrT-1 used in this study was in clade IV for the CP phylogenetic tree whereas it formed a separate branch in the 2b phylogenetic tree. The nucleotide sequence diversity of both the 2b and CP genes was low (0.062 +/- A 0.006 and 0.063 +/- A 0.006 for 2b and CP, respectively) bu…
The fitness effects of synonymous mutations in DNA and RNA viruses.
2011
Despite being silent with respect to protein sequence, synonymous nucleotide substitutions can be targeted by natural selection directly at the DNA or RNA level. However, there has been no systematic assessment of how frequent this type of selection is. Here, we have constructed 53 single random synonymous substitution mutants of the bacteriophages Qb and UX174 by site-directed mutagenesis and assayed their fitness. Analysis of this mutant collection and of previous studies undertaken with a variety of single-stranded (ss) viruses demonstrates that selection at synonymous sites is stronger in RNA viruses than in DNA viruses. We estimate that this type of selection contributes approximately …
Tick-borne encephalitis virus, Borrelia burgdorferi sensu lato, Borrelia miyamotoi, Anaplasma phagocytophilum and Candidatus Neoehrlichia mikurensis …
2018
The aim of this study was to determine the occurrence of tick-borne pathogens of medical importance in questing ticks collected from five recreationally used islands along the Norwegian coastline. Furthermore, since coinfection may affect the disease severity, this study aimed to determine the extent of coinfection in individual ticks or co-localization of tick-borne pathogens. In all, 4158 questing Ixodes ricinus ticks were analyzed. For detection of tick-borne encephalitis virus (TBEV), nymphs (3690) were analyzed in pools of ten. To detect Borrelia burgdorferi sensu lato, B. miyamotoi, Anaplasma phagocytophilum and Candidatus Neoehrlichia mikurensis, 468 nymphs were analyzed individually…
Baculovirus infection affects caterpillar chemoperception
2021
International audience; Baculoviruses are double-stranded DNA entomopathogenic viruses that infect predominantly insects of the order Lepidoptera. Research in the last decade has started to disentangle the mechanisms underlying the insect-virus interaction, particularly focusing on the effects of the baculovirus infection in the host's physiology. Among crucial physiological functions, olfaction has a key role in reproductive tasks, food source detection and enemy avoidance. In this work, we describe that Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) induces expression changes in some odorant receptors (ORs)-the centrepiece of insect's olfaction-when infecting larvae from its nat…
Synthesis and assembly of virus-like particles of human papillomaviruses type 6 and type 16 in fission yeast Schizosaccharomyces pombe.
1995
AbstractWe have synthesized capsid proteins of human papillomavirus types 6 (HPV 6) and 16 (HPV 16) in fission yeast Schizosaccharomyces pombe and produced virus-like particles (VLP). The capsid proteins were localized in the nucleus by indirect immunofluorescence and cell fractionation analyses. The VLP were produced in both yeast clones synthesizing L1 alone and L1/L2 and purified by sulfato-cellulofine chromatography. Electron microscopic examination showed that these VLP were similar in structure to native HPV particles. Two HPV 16 L1 variants (16 B27L1 and 16 T3L1), isolated from benign cervical samples, produced many more (68- and 14-fold) VLP than the prototype L1 (16 PL1) derived fr…
Time trends of human papillomavirus types in invasive cervical cancer, from 1940 to 2007.
2013
Contribution over time of human papillomavirus (HPV) types in human cancers has been poorly documented. Such data is fundamental to measure current HPV vaccines impact in the years to come. We estimated the HPV type-specific distribution in a large international series of invasive cervical cancer (ICC) over 70 years prior to vaccination. Paraffin embedded ICC cases diagnosed between 1940 and 2007 were retrieved from eleven countries in Central-South America, Asia and Europe. Included countries reported to have low-medium cervical cancer screening uptake. Information on age at and year of diagnosis was collected from medical records. After histological confirmation, HPV DNA detection was per…
Human papillomavirus genotype attribution in invasive cervical cancer: a retrospective cross-sectional worldwide study.
2010
Summary Background Knowledge about the distribution of human papillomavirus (HPV) genotypes in invasive cervical cancer is crucial to guide the introduction of prophylactic vaccines. We aimed to provide novel and comprehensive data about the worldwide genotype distribution in patients with invasive cervical cancer. Methods Paraffin-embedded samples of histologically confirmed cases of invasive cervical cancer were collected from 38 countries in Europe, North America, central South America, Africa, Asia, and Oceania. Inclusion criteria were a pathological confirmation of a primary invasive cervical cancer of epithelial origin in the tissue sample selected for analysis of HPV DNA, and informa…