Search results for " viruses"
showing 10 items of 230 documents
Nonlinear trade-offs allow the cooperation game to evolve from Prisoner's Dilemma to Snowdrift.
2017
[EN] The existence of cooperation, or the production of public goods, is an evolutionary problem. Cooperation is not favoured because the Prisoner s Dilemma (PD) game drives cooperators to extinction. We have re-analysed this problem by using RNA viruses to motivate a model for the evolution of cooperation. Gene products are the public goods and group size is the number of virions co-infecting the same host cell. Our results show that if the trade-off between replication and production of gene products is linear, PD is observed. However, if the trade-off is nonlinear, the viruses evolve into separate lineages of ultra-defectors and ultra-cooperators as group size is increased. The nonlinear…
Assessing the burden of viral co-infections in acute gastroenteritis in children: An eleven-year-long investigation.
2020
Abstract Background Acute gastroenteritis is an important cause of childhood morbidity and mortality worldwide. A number of pathogens are responsible for human acute gastroenteritis. The recent introduction of syndromic assays for the diagnosis of enteric infections, including a wide panel of enteric pathogens, has unveiled the frequency of mixed infections. This study was carried out to assess the burden of viral co-infections and the genetic diversity of the viruses detected in children hospitalized with acute gastroenteritis in Italy. Methods A total of 4161 stool samples collected from diarrheic children over 11 years, from January 2008 to December 2018, were investigated for the presen…
Ortervirales: New Virus Order Unifying Five Families of Reverse-Transcribing Viruses
2018
International audience; Reverse-transcribing viruses, which synthesize a copy of genomic DNA from an RNA template, are widespread in animals, plants, algae, and fungi (1, 2). This broad distribution suggests the ancient origin(s) of these viruses, possibly [...]
Increased RNA virus population diversity improves adaptability
2021
The replication machinery of most RNA viruses lacks proofreading mechanisms. As a result, RNA virus populations harbor a large amount of genetic diversity that confers them the ability to rapidly adapt to changes in their environment. In this work, we investigate whether further increasing the initial population diversity of a model RNA virus can improve adaptation to a single selection pressure, thermal inactivation. For this, we experimentally increased the diversity of coxsackievirus B3 (CVB3) populations across the capsid region. We then compared the ability of these high diversity CVB3 populations to achieve resistance to thermal inactivation relative to standard CVB3 populations in an…
Viral replication modes in single-peak fitness landscapes: A dynamical systems analysis
2017
Positive-sense, single-stranded RNA viruses are important pathogens infecting almost all types of organisms. Experimental evidence from distributions of mutations and from viral RNA amplification suggest that these pathogens may follow different RNA replication modes, ranging from the stamping machine replication (SMR) to the geometric replication (GR) mode. Although previous theoretical work has focused on the evolutionary dynamics of RNA viruses amplifying their genomes with different strategies, little is known in terms of the bifurcations and transitions involving the so-called error threshold (mutation-induced dominance of mutants) and lethal mutagenesis (extinction of all sequences du…
Exploring Strategies for Labeling Viruses with Gold Nanoclusters through Non-equilibrium Molecular Dynamics Simulations.
2017
Biocompatible gold nanoclusters can be utilized as contrast agents in virus imaging. The labeling of viruses can be achieved noncovalently but site-specifically by linking the cluster to the hydrophobic pocket of a virus via a lipid-like pocket factor. We have estimated the binding affinities of three different pocket factors of echovirus 1 (EV1) in molecular dynamics simulations combined with non-equilibrium free-energy calculations. We have also studied the effects on binding affinities with a pocket factor linked to the Au102pMBA44 nanocluster in different protonation states. Although the absolute binding affinities are over-estimated for all the systems, the trend is in agreement with r…
Chromatin organization regulates viral egress dynamics.
2017
Various types of DNA viruses are known to elicit the formation of a large nuclear viral replication compartment and marginalization of the cell chromatin. We used three-dimensional soft x-ray tomography, confocal and electron microscopy, combined with numerical modelling of capsid diffusion to analyse the molecular organization of chromatin in herpes simplex virus 1 infection and its effect on the transport of progeny viral capsids to the nuclear envelope. Our data showed that the formation of the viral replication compartment at late infection resulted in the enrichment of heterochromatin in the nuclear periphery accompanied by the compaction of chromatin. Random walk modelling of herpes s…
Virotherapy in Germany—Recent Activities in Virus Engineering, Preclinical Development, and Clinical Studies
2021
Virotherapy research involves the development, exploration, and application of oncolytic viruses that combine direct killing of cancer cells by viral infection, replication, and spread (oncolysis) with indirect killing by induction of anti-tumor immune responses. Oncolytic viruses can also be engineered to genetically deliver therapeutic proteins for direct or indirect cancer cell killing. In this review—as part of the special edition on “State-of-the-Art Viral Vector Gene Therapy in Germany”—the German community of virotherapists provides an overview of their recent research activities that cover endeavors from screening and engineering viruses as oncolytic cancer therapeutics to their cli…
Monitoring of ticks and tick-borne pathogens through a nationwide research station network in Finland.
2020
In 2015 a long-term, nationwide tick and tick-borne pathogen (TBP) monitoring project was started by the Finnish Tick Project and the Finnish Research Station network (RESTAT), with the goal of producing temporally and geographically extensive data regarding exophilic ticks in Finland. In the current study, we present results from the first four years of this collaboration. Ticks were collected by cloth dragging from 11 research stations across Finland in May September 2015-2018 (2012-2018 in Seili). Collected ticks were screened for twelve different pathogens by qPCR: Borrelia afzelii, Borrelia garinii, Borrelia valaisiana, Borrelia burgdorferi sensu stricto, Borrelia miyamotoi, Babesia sp…
Novel activities of safe-in-human broad-spectrum antiviral agents
2018
According to the WHO, there is an urgent need for better control of viral diseases. Re-positioning existing safe-in-human antiviral agents from one viral disease to another could play a pivotal role in this process. Here, we reviewed all approved, investigational and experimental antiviral agents, which are safe in man, and identified 59 compounds that target at least three viral diseases. We tested 55 of these compounds against eight different RNA and DNA viruses. We found novel activities for dalbavancin against echovirus 1, ezetimibe against human immunodeficiency virus 1 and Zika virus, as well as azacitidine, cyclosporine, minocycline, oritavancin and ritonavir against Rift valley feve…