Search results for "IRI"

A Dirichlet Autoregressive Model for the Analysis of Microbiota Time-Series Data

2021

Growing interest in understanding microbiota dynamics has motivated the development of different strategies to model microbiota time series data. However, all of them must tackle the fact that the available data are high-dimensional, posing strong statistical and computational challenges. In order to address this challenge, we propose a Dirichlet autoregressive model with time-varying parameters, which can be directly adapted to explain the effect of groups of taxa, thus reducing the number of parameters estimated by maximum likelihood. A strategy has been implemented which speeds up this estimation. The usefulness of the proposed model is illustrated by application to a case study.

Assessment of prevalence and load of torquetenovirus viraemia in a large cohort of healthy blood donors.

2020

OBJECTIVES: Torquetenovirus (TTV) is an emerging marker of functional immune competence with the potential to predict transplant-related adverse events. A large-scale epidemiological study was performed to understand how basal values vary in healthy individuals according to age and gender.; METHODS: We tested plasma from 1017 healthy blood donors aged 18-69years. The presence and load of TTV were determined by a real-time PCR assay. A sub-cohort of 384 donors was tested for anti-cytomegalovirus IgG antibodies, and 100 participants were also tested for TTV viraemia on a paired whole blood sample.; RESULTS: The overall prevalence of TTV was 65% (657/1017) with a mean (±SD) growth of 5±4% ever…

Recombinant GII.P16 genotype challenges RT-PCR-based typing in region A of norovirus genome

2021

Abstract Objectives In latest years GII.4[P16] and GII.2[P16] noroviruses have become predominant in some temporal/geographical settings. In parallel with the emergence of the GII.P16 polymerase type, norovirus surveillance activity in Italy experienced increasing difficulties in generating sequence data on the RNA polymerase genomic region A, using the widely adopted JV12A/JV13B primer set. Two sets of modified primers (Deg1 and Deg2) were tested in order to improve amplification and typing of the polymerase gene. Methods Amplification and typing performance of region A primers was assessed in RT-PCR on 452 GII norovirus positive samples obtained from 2194 stool samples collected in 2016–2…

Analysis of GII.P7 and GII.6 noroviruses circulating in Italy during 2011-2016 reveals a replacement of lineages and complex recombination history.

2019

Noroviruses are important human enteric pathogens and monitoring their genetic diversity is important for epidemiological surveillance, vaccine development, and understanding of RNA viruses evolution. Epidemiological investigations have revealed that genogroup II, genotype 6 noroviruses (GII.6) are common agents of gastroenteritis. Upon sequencing of the ORF2 (encoding the viral capsid), GII.6 viruses have been distinguished into three variants. Sentinel hospital-based surveillance in Italy revealed that GII.6 noroviruses were the second most common capsid genotype in 2015, mostly in association with a GII.P7 ORF1 (encoding the viral polymerase). Upon molecular characterization of the ORF1 …

The BioFireFilmArray enables point of care diagnostic in neonatal parechovirus meningitis.

2017

Sir,We read with great interest a report in the present journal on the application of broad-range PCR combined with DNA sequencing for detection of bacteria in cerebrospinal fluid (CSF) [1]. This m...

Detection of Viral −RNA and +RNA Strands in Enterovirus-Infected Cells and Tissues

2020

The current methods to study the distribution and dynamics of viral RNA molecules inside infected cells are not ideal, as electron microscopy and immunohistochemistry can only detect mature virions, and quantitative real-time PCR does not reveal localized distribution of RNAs. We demonstrated here the branched DNA in situ hybridization (bDNA ISH) technology to study both the amount and location of the emerging &minus

Linking Only Aedes aegypti with Zika Virus Has World-Wide Public Health Implications

2017

Multi-virion infectious units arise from free viral particles in an enveloped virus

2017

Many animal viruses are enveloped in a lipid bilayer uptaken from cellular membranes. Since viral surface proteins bind to these membranes to initiate infection, we hypothesized that free virions may also be capable of interacting with the envelopes of other virions extracellularly. Here, we demonstrate this hypothesis in the vesicular stomatitis virus (VSV), a prototypic negative-strand RNA virus composed by an internal ribonucleocapsid, a matrix protein, and an external envelope1. Using microscopy, dynamic light scattering, differential centrifugation, and flow cytometry, we show that free viral particles can spontaneously aggregate into multi-virion infectious units. We also show that, f…

Collective Infectious Units in Viruses

2017

Increasing evidence indicates that viruses do not simply propagate as independent virions among cells, organs, and hosts. Instead, viral spread is often mediated by structures that simultaneously transport groups of viral genomes, such as polyploid virions, aggregates of virions, virion-containing proteinaceous structures, secreted lipid vesicles, and virus-induced cell-cell contacts. These structures increase the multiplicity of infection, independently of viral population density and transmission bottlenecks. Collective infectious units may contribute to the maintenance of viral genetic diversity, and could have implications for the evolution of social-like virus-virus interactions. These…

Functional display of an alpha2 integrin-specific motif (RKK) on the surface of baculovirus particles.

2005

The use of baculovirus vectors shows promise as a tool for gene delivery into mammalian cells. These insect viruses have been shown to transduce a variety of mammalian cell lines, and gene transfer has also been demonstrated in vivo. In this study, we generated two recombinant baculovirus vectors displaying an integrin-specific motif, RKK, as a part of two different loops of the green fluorescent protein (GFP) fused with the major envelope protein gp64 of Autographa californica M nucleopolyhedrovirus. By enzyme linked immunosorbent assays, these viruses were shown to bind a peptide representing the receptor binding site of an α2 integrin, the α2I-domain. However, the interaction was not st…