Search results for "Virus"

Comprehensive Screening for Naturally Occurring Hepatitis C Virus Resistance to Direct-Acting Antivirals in the NS3, NS5A, and NS5B Genes in Worldwid…

2015

ABSTRACTThere is no comprehensive study available on the natural hepatitis C virus (HCV) polymorphism in sites associated with resistance including all viral genotypes which may present variable susceptibilities to particular direct-acting antivirals (DAAs). This study aimed to analyze the frequencies, genetic barriers, and evolutionary histories of naturally occurring resistance-associated variants (RAVs) in the six main HCV genotypes. A comprehensive analysis of up to 103 RAVs was performed in 2,901, 2,216, and 1,344 HCV isolates for the NS3, NS5A, and NS5B genes, respectively. We report significant intergenotypic differences in the frequencies of natural RAVs for these three HCV genes. I…

ceRNA Network Regulation of TGF-β, WNT, FOXO, Hedgehog Pathways in the Pharynx of Ciona robusta

2021

The transforming growth factor-β (TGF-β) family of cytokines performs a multifunctional signaling, which is integrated and coordinated in a signaling network that involves other pathways, such as Wintless, Forkhead box-O (FOXO) and Hedgehog and regulates pivotal functions related to cell fate in all tissues. In the hematopoietic system, TGF-β signaling controls a wide spectrum of biological processes, from immune system homeostasis to the quiescence and self-renewal of hematopoietic stem cells (HSCs). Recently an important role in post-transcription regulation has been attributed to two type of ncRNAs: microRNAs and pseudogenes. Ciona robusta, due to its philogenetic position close to verte…

Host Cell Rab GTPases in Hepatitis B Virus Infection

2018

Hepatitis B virus (HBV) is a leading cause of liver disease and is presently estimated to infect more than 250 million humans. The extremely successful spread of this virus among the human population is explained by its effective transmission strategies and its manifold particle types, including virions, empty envelopes and naked capsids. Due to its tiny genome, HBV depends on cellular machineries to thrive in infected hepatocytes. To enter, traverse and exit the cell, HBV exploits host membrane trafficking pathways, including intracellular highways directed by Rab GTPases. Here, we review recent discoveries focused on how HBV co-opts and perturbs host Rab GTPase functions with an emphasis …

Extending the hosts of Tectiviridae into four additional genera of Gram-positive bacteria and more diverse Bacillus species

2017

Abstract Tectiviridae are composed of tailless bacteriophages with an icosahedral capsid and an inner membrane enclosing a double-stranded 15 kb linear DNA genome. Five of the seven previously studied Tectivirus isolates infect bacteria from Bacillus cereus sensu lato group (Betatectivirus), one distantly related member (PRD1) infect Enterobactericeae (Alpatectivirus) and one recently discovered virus infect Gluconobacter cerinus (Gammatectivirus). Here we expand the host spectrum of Betatectivirus elements to four additional genera (Streptococcus, Exiguobacterium, Clostridium and Brevibacillus) and to more distantly related Bacillus species (B. pumilus and B. flexus) by studying the genome…

ICTV Virus Taxonomy Profile: Finnlakeviridae

2020

Finnlakeviridae is a family of icosahedral, internal membrane-containing bacterial viruses with circular, single-stranded DNA genomes. The family includes the genus, Finnlakevirus, with the species, Flavobacterium virus FLiP. Flavobacterium phage FLiP was isolated with its Gram-negative host bacterium from a boreal freshwater habitat in Central Finland in 2010. It is the first described single-stranded DNA virus with an internal membrane and shares minimal sequence similarity with other known viruses. The virion organization (pseudo T=21 dextro) and major capsid protein fold (double-β-barrel) resemble those of Pseudoalteromonas phage PM2 (family Corticoviridae), which has a double-stranded…

How to best manage cytomegalovirus infection in the allogeneic stem cell transplant setting: future prospects

2016

Expanding role of cytomegalovirus as a human pathogen

2016

Cytomegalovirus (CMV) continues to be a leading cause of morbidity and mortality in transplant recipients, despite major advancements in preventative strategies. Antiviral prophylaxis and pre-emptive antiviral therapeutic regimens are associated with a high incidence of late-onset end-organ disease and cause drug-related toxicity when overused. Therefore, the identification of risk factors for CMV replication is required. Genetic and immunological factors that predispose individuals to CMV-related clinical complications have been identified and may be instrumental for optimizing CMV treatment in the future. Evidence suggests a causal pathogenetic link between CMV-related complications and i…

Survival of Enteric Viruses in the Environment and Food

2016

Enteric viruses are those human viruses that are primarily transmitted by the fecal-oral route, either by person-to-person contact or by ingestion of contaminated food or water. The importance of viral foodborne diseases is increasingly being recognized, and several international organizations have found that there is an upward trend in their incidence. Thus, in this review, state-of-the-art information regarding virus persistence in food and the environment is compiled.

Associating HIV-1 envelope glycoprotein structures with states on the virus observed by smFRET

2019

The HIV-1 envelope glycoprotein (Env) trimer mediates cell entry and is conformationally dynamic1-8. Imaging by single-molecule fluorescence resonance energy transfer (smFRET) has revealed that, on the surface of intact virions, mature pre-fusion Env transitions from a pre-triggered conformation (state 1) through a default intermediate conformation (state 2) to a conformation in which it is bound to three CD4 receptor molecules (state 3)8-10. It is currently unclear how these states relate to known structures. Breakthroughs in the structural characterization of the HIV-1 Env trimer have previously been achieved by generating soluble and proteolytically cleaved trimers of gp140 Env that are …

Synergistic Anti-Human Immunodeficiency Viral (HIV-1) Effect of the Immunomodulator Ampligen (Mismatched Double-Stranded RNA) with Inhibitors of Reve…

1993

The potent antiviral effect of double stranded RNA, such as the mismatched poly(l)·poly(C12U) [Ampligen], 2′,3′-dideoxy-3′-fluorothymidine (FddThd) and antisense oligodeoxynucleotides (ODN) has been established in in vitro systems using cells infected with the human immunodeficiency virus type 1 (HIV-1). We report here that the immunomodulator poly(l)·poly(C12U) interacts synergistically with (1) the reverse transcriptase inhibitor FddThd (FIC value: 0.43), (2) the modified (5′- and 3′-end capped thioates) antisense ODN-4 directed against the splice acceptor site of the HIV-1/ tat gene (FIC value: 0.66) and (3) also with pyronin Y, a compound which prevents binding of HIV-1 Rev protein to t…