keyword
MENU ▼
Read by QxMD icon Read
search

Quasispecies

keyword
https://www.readbyqxmd.com/read/28207488/lessons-learned-from-humoral-responses-of-hiv-patients
#1
Laura E McCoy, Áine McKnight
PURPOSE OF REVIEW: Since 2009 many broadly neutralizing antibodies against HIV have been identified, yet there is still no vaccine capable of inducing such antibodies in humans. This review considers the early observations of HIV sera neutralization in light of more recent studies and highlights areas for future research. RECENT FINDINGS: Large clinical cohort studies using standardized neutralization assays and pseudoviruses derived from primary isolates have shown that 10-30% of HIV infections result in some level of serum neutralization breadth...
February 15, 2017: Current Opinion in HIV and AIDS
https://www.readbyqxmd.com/read/28205569/heteroaryldihydropyrimidine-hap-and-sulfamoylbenzamide-sba-inhibit-hepatitis-b-virus-replication-by-different-molecular-mechanisms
#2
Zheng Zhou, Taishan Hu, Xue Zhou, Steffen Wildum, Fernando Garcia-Alcalde, Zhiheng Xu, Daitze Wu, Yi Mao, Xiaojun Tian, Yuan Zhou, Fang Shen, Zhisen Zhang, Guozhi Tang, Isabel Najera, Guang Yang, Hong C Shen, John A T Young, Ning Qin
Heteroaryldihydropyrimidine (HAP) and sulfamoylbenzamide (SBA) are promising non-nucleos(t)ide HBV replication inhibitors. HAPs are known to promote core protein mis-assembly, but the molecular mechanism of abnormal assembly is still elusive. Likewise, the assembly status of core protein induced by SBA remains unknown. Here we show that SBA, unlike HAP, does not promote core protein mis-assembly. Interestingly, two reference compounds HAP_R01 and SBA_R01 bind to the same pocket at the dimer-dimer interface in the crystal structures of core protein Y132A hexamer...
February 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28197136/characterization-of-the-genomic-diversity-of-norovirus-in-linked-patients-using-a-metagenomic-deep-sequencing-approach
#3
Neda Nasheri, Nicholas Petronella, Jennifer Ronholm, Sabah Bidawid, Nathalie Corneau
Norovirus (NoV) is the leading cause of gastroenteritis worldwide. A robust cell culture system does not exist for NoV and therefore detailed characterization of outbreak and sporadic strains relies on molecular techniques. In this study, we employed a metagenomic approach that uses non-specific amplification followed by next-generation sequencing to whole genome sequence NoV genomes directly from clinical samples obtained from 8 linked patients. Enough sequencing depth was obtained for each sample to use a de novo assembly of near-complete genome sequences...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28181035/complete-genome-sequence-of-a-hepatitis-b-virus-isolate-of-genotype-d2-subtype-adrq-from-brazil
#4
Natália Spitz, Aline S Moreira, Francisco C A Mello, Helena Cristina F Franz, Selma A Gomes, Natalia M Araujo
Hepatitis B virus (HBV) has been classified into 10 distinct serological subtypes of the surface antigen (HBsAg) that can be predicted by sequencing of the corresponding S gene. HBV genotype D usually displays determinants of subtypes ayw2 or ayw3. On the other hand, subtype adrq+ has been found exclusively in association with genotype C. Here, we describe the first HBV genome (isolate BR32) belonging to genotype D with the serological subtype adrq+. This isolate had a genome length of 3,062 nucleotides (nt), and no recombination events were observed in the BR32 genome that could explain the occurrence of the subtype adr in a genotype D isolate...
February 8, 2017: Archives of Virology
https://www.readbyqxmd.com/read/28163093/picornaviral-polymerase-structure-function-and-fidelity-modulation
#5
REVIEW
Olve B Peersen
Like all positive strand RNA viruses, the picornaviruses replicate their genomes using a virally encoded RNA-dependent RNA polymerase enzyme known as 3D(pol). Over the past decade we have made tremendous advances in our understanding of 3D(pol) structure and function, including the discovery of a novel mechanism for closing the active site that allows these viruses to easily fine tune replication fidelity and quasispecies distributions. This review summarizes current knowledge of picornaviral polymerase structure and how the enzyme interacts with RNA and other viral proteins to form stable and processive elongation complexes...
February 2, 2017: Virus Research
https://www.readbyqxmd.com/read/28134353/baseline-quasispecies-selection-and-novel-mutations-contribute-to-emerging-resistance-associated-substitutions-in-hepatitis-c-virus-after-direct-acting-antiviral-treatment
#6
Yugo Kai, Hayato Hikita, Naoki Morishita, Kazuhiro Murai, Tasuku Nakabori, Sadaharu Iio, Hideki Hagiwara, Yasuharu Imai, Shinji Tamura, Syusaku Tsutsui, Masafumi Naito, Meiko Nishiuchi, Yasuteru Kondo, Takanobu Kato, Hiroshi Suemizu, Ryoko Yamada, Tsugiko Oze, Takayuki Yakushijin, Naoki Hiramatsu, Ryotaro Sakamori, Tomohide Tatsumi, Tetsuo Takehara
Resistance-associated substitutions (RASs) in hepatitis C virus (HCV) appear upon failure of treatment with direct-acting antivirals (DAAs). However, their origin has not been clarified in detail. Among 11 HCV genotype 1b patients who experienced virologic failure with asunaprevir (ASV)/daclatasvir (DCV), 10 had major NS5A L31M/V-Y93H variants after treatment. L31M/V-Y93H variants were detected as a minor clone before therapy in 6 patients and were the most closely related to the post-treatment variants by phylogenetic tree analysis in 4 patients...
January 30, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28103248/effect-of-the-latent-reservoir-on-the-evolution-of-hiv-at-the-within-and-between-host-levels
#7
Hilje M Doekes, Christophe Fraser, Katrina A Lythgoe
The existence of long-lived reservoirs of latently infected CD4+ T cells is the major barrier to curing HIV, and has been extensively studied in this light. However, the effect of these reservoirs on the evolutionary dynamics of the virus has received little attention. Here, we present a within-host quasispecies model that incorporates a long-lived reservoir, which we then nest into an epidemiological model of HIV dynamics. For biologically plausible parameter values, we find that the presence of a latent reservoir can severely delay evolutionary dynamics within a single host, with longer delays associated with larger relative reservoir sizes and/or homeostatic proliferation of cells within the reservoir...
January 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28073402/deep-sequencing-analysis-of-tick-borne-encephalitis-virus-from-questing-ticks-at-natural-foci-reveals-similarities-between-quasispecies-pools-of-the-virus
#8
Naveed Asghar, John H-O Pettersson, Patrik Dinnetz, Åshild Andreassen, Magnus Johansson
Every year, tick-borne encephalitis virus (TBEV) causes severe central nervous system infection in 10,000 to 15,000 people in Europe and Asia. TBEV is maintained in the environment by an enzootic cycle that requires a tick vector and a vertebrate host, and the adaptation of TBEV to vertebrate and invertebrate environments is essential for TBEV persistence in nature. This adaptation is facilitated by the error-prone nature of the virus' RNA-dependent RNA polymerase that generates genetically distinct virus variants called quasispecies...
January 10, 2017: Journal of General Virology
https://www.readbyqxmd.com/read/28072889/in-depth-analysis-of-compartmentalization-of-hiv-1-matrix-protein-p17-in-pbmc-and-plasma
#9
Marina Selleri, Riccardo Dolcetti, Francesca Caccuri, Emanuela Giombini, Gabriella Rozera, Isabella Abbate, Alessia Mammone, Stefania Zanussi, Debora Martorelli, Simona Fiorentini, Arnaldo Caruso, Maria Rosaria Capobianchi
HIV-1 p17 plays an important role in the virus life-cycle and disease pathogenesis. Recent studies indicated a high heterogeneity of p17. A high number of insertions in the p17 carboxy-terminal region have been more frequently detected in patients with non-Hodgkin lymphoma (NHL), suggesting a role of altered p17 in lymphomagenesis. Based on p17 heterogeneity, possible PBMC/plasma compartmentalization of p17 variants was explored by ultra-deep pyrosequencing in five NHL patients. The high variability of p17 with insertions at the carboxy-terminal region was confirmed in plasma and observed for the first time in proviral genomes...
January 9, 2017: New Microbiologica
https://www.readbyqxmd.com/read/28069935/resistance-to-type-1-interferons-is-a-major-determinant-of-hiv-1-transmission-fitness
#10
Shilpa S Iyer, Frederic Bibollet-Ruche, Scott Sherrill-Mix, Gerald H Learn, Lindsey Plenderleith, Andrew G Smith, Hannah J Barbian, Ronnie M Russell, Marcos V P Gondim, Catherine Y Bahari, Christiana M Shaw, Yingying Li, Timothy Decker, Barton F Haynes, George M Shaw, Paul M Sharp, Persephone Borrow, Beatrice H Hahn
Sexual transmission of HIV-1 is an inefficient process, with only one or few variants of the donor quasispecies establishing the new infection. A critical, and as yet unresolved, question is whether the mucosal bottleneck selects for viruses with increased transmission fitness. Here, we characterized 300 limiting dilution-derived virus isolates from the plasma, and in some instances genital secretions, of eight HIV-1 donor and recipient pairs. Although there were no differences in the amount of virion-associated envelope glycoprotein, recipient isolates were on average threefold more infectious (P = 0...
January 24, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28040474/deep-sequencing-in-the-management-of-hepatitis-virus-infections
#11
REVIEW
Josep Quer, Francisco Rodríguez-Frias, Josep Gregori, David Tabernero, Maria Eugenia Soria, Damir García-Cehic, Maria Homs, Albert Bosch, Rosa María Pintó, Juan Ignacio Esteban, Esteban Domingo, Celia Perales
The hepatitis viruses represent a major public health problem worldwide. Procedures for characterization of the genomic composition of their populations, accurate diagnosis, identification of multiple infections, and information on inhibitor-escape mutants for treatment decisions are needed. Deep sequencing methodologies are extremely useful for these viruses since they replicate as complex and dynamic quasispecies swarms whose complexity and mutant composition are biologically relevant traits. Population complexity is a major challenge for disease prevention and control, but also an opportunity to distinguish among related but phenotypically distinct variants that might anticipate disease progression and treatment outcome...
December 28, 2016: Virus Research
https://www.readbyqxmd.com/read/28027000/viroid-quasispecies-revealed-by-deep-sequencing
#12
Joseph R J Brass, Robert A Owens, Jaroslav Matoušek, Gerhard Steger
Viroids are non-coding single-stranded circular RNA molecules that replicate autonomously in infected host plants causing mild to lethal symptoms. Their genomes contain about 250-400 nucleotides, depending on viroid species. Members of the family Pospiviroidae, like the Potato spindle tuber viroid (PSTVd), replicate via an asymmetric rolling-circle mechanism using the host DNA-dependent RNA-Polymerase II in the nucleus, while members of Avsunviroidae are replicated in a symmetric rolling-circle mechanism probably by the nuclear-encoded polymerase in chloroplasts...
December 27, 2016: RNA Biology
https://www.readbyqxmd.com/read/28024238/forensic-application-of-phylogenetic-analyses-exploration-of-suspected-hiv-1-transmission-case
#13
Marina Siljic, Dubravka Salemovic, Valentina Cirkovic, Ivana Pesic-Pavlovic, Jovan Ranin, Marija Todorovic, Slobodan Nikolic, Djordje Jevtovic, Maja Stanojevic
Transmission of human immunodeficiency virus (HIV) between individuals may have important legal implications and therefore may come to require forensic investigation based upon phylogenetic analysis. In criminal trials results of phylogenetic analyses have been used as evidence of responsibility for HIV transmission. In Serbia, as in many countries worldwide, exposure and deliberate transmission of HIV are criminalized. We present the results of applying state of the art phylogenetic analyses, based on pol and env genetic sequences, in exploration of suspected HIV transmission among three subjects: a man and two women, with presumed assumption of transmission direction from one woman to a man...
December 19, 2016: Forensic Science International. Genetics
https://www.readbyqxmd.com/read/28012998/viral-small-rnas-reveal-the-genomic-variations-of-three-grapevine-vein-clearing-virus-quasispecies-populations
#14
Susanne Howard, Wenping Qiu
Viral small RNAs (vsRNAs) include viral small interfering RNAs (vsiRNAs) that are initiators and products of RNA silencing, and small RNAs that are derived from viral RNAs with function still unknown. Sequencing of vsRNAs allows assembling of viral genomes and revelation of viral population variations at genomic levels. Grapevine vein clearing virus (GVCV) is a new member of the family Caulimoviridae whose DNA genome is replicated by reverse transcription of pre-genomic RNA molecules. In this short report, three genomic sequences of GVCV were assembled from vsRNAs that were isolated and sequenced from three individual grapevines in commercial vineyards and compared to the GVCV-CHA reference genome...
February 2, 2017: Virus Research
https://www.readbyqxmd.com/read/28011961/genotypic-analysis-of-hcv-1a-by-sequencing-of-the-ns3-proteasic-region-in-simeprevir-therapy-candidates
#15
Alfonso Liberti, Adriana Raddi, Nunzia Cuomo
Each phase of the HCV replication cycle can represent a therapy target. In fact, SIMEPREVIR (SMV) acts as NS3/4A protease inhibitor (PI); its efficacy is, however, reduced in HCV1a patients characterized by NS3Q80K polymorphism. The aim of this work was to design a genotypic analysis of NS3 protease in order to characterize viral quasispecies in HCV 1a patients before starting the SMV therapy. In all, 38 peripheral blood-EDTA samples were collected from patients infected with HCV 1a (RNA > 10,000 cp/ml)...
1, 2016: Le Infezioni in Medicina
https://www.readbyqxmd.com/read/27993149/a-deep-sequencing-reveals-significant-diversity-among-dominant-variants-and-evolutionary-dynamics-of-avian-leukosis-viruses-in-two-infectious-ecosystems
#16
Fanfeng Meng, Xuan Dong, Tao Hu, Shuang Chang, Jianhua Fan, Peng Zhao, Zhizhong Cui
BACKGROUND: As a typical retrovirus, the evolution of Avian leukosis virus subgroup J (ALV-J) in different infectious ecosystems is not characterized, what we know is there are a cloud of diverse variants, namely quasispecies with considerable genetic diversity. This study is to explore the selection of infectious ecosystems on dominant variants and their evolutionary dynamics of ALV-J between DF1 cells and specific-pathogen-free (SPF) chickens. High-throughput sequencing platforms provide an approach for detecting quasispecies diversity more fully...
December 19, 2016: BMC Veterinary Research
https://www.readbyqxmd.com/read/27982069/the-role-of-the-poly-a-tract-in-the-replication-and-virulence-of-tick-borne-encephalitis-virus
#17
Naveed Asghar, Yi-Ping Lee, Emma Nilsson, Richard Lindqvist, Wessam Melik, Andrea Kröger, Anna K Överby, Magnus Johansson
The tick-borne encephalitis virus (TBEV) is a flavivirus transmitted to humans, usually via tick bites. The virus causes tick-borne encephalitis (TBE) in humans, and symptoms range from mild flu-like symptoms to severe and long-lasting sequelae, including permanent brain damage. It has been suggested that within the population of viruses transmitted to the mammalian host, quasispecies with neurotropic properties might become dominant in the host resulting in neurological symptoms. We previously demonstrated the existence of TBEV variants with variable poly(A) tracts within a single blood-fed tick...
December 16, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27975319/deep-sequencing-of-the-hepatitis-b-virus-genome-analysis-of-multiple-samples-by-implementation-of-the-illumina-platform
#18
Quan-Xin Long, Jie-Li Hu, Ai-Long Huang
The quasispecies variation of hepatitis B virus (HBV) was believed to be a viral response to antiviral treatment and host immune pressure. Sanger sequencing was previously the classic approach for quasispecies analysis, but this method was also time-consuming and laborious. Ultra-deep sequencing has been widely used in viral quasispecies research, especially for low-frequency mutation detection. Here we present a multiple samples deep sequencing method employing the Illumina platform to detect HBV quasispecies variation in patient-derived samples...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27959928/an-efficient-microarray-based-genotyping-platform-for-the-identification-of-drug-resistance-mutations-in-majority-and-minority-subpopulations-of-hiv-1-quasispecies
#19
Verónica Martín, Celia Perales, María Fernández-Algar, Helena G Dos Santos, Patricia Garrido, María Pernas, Víctor Parro, Miguel Moreno, Javier García-Pérez, José Alcamí, José Luis Torán, David Abia, Esteban Domingo, Carlos Briones
The response of human immunodeficiency virus type 1 (HIV-1) quasispecies to antiretroviral therapy is influenced by the ensemble of mutants that composes the evolving population. Low-abundance subpopulations within HIV-1 quasispecies may determine the viral response to the administered drug combinations. However, routine sequencing assays available to clinical laboratories do not recognize HIV-1 minority variants representing less than 25% of the population. Although several alternative and more sensitive genotyping techniques have been developed, including next-generation sequencing (NGS) methods, they are usually very time consuming, expensive and require highly trained personnel, thus becoming unrealistic approaches in daily clinical practice...
2016: PloS One
https://www.readbyqxmd.com/read/27920481/new-real-time-pcr-method-to-identify-single-point-mutations-in-hepatitis-c-virus
#20
Qian Chen, Irene Belmonte, Maria Buti, Leonardo Nieto, Damir Garcia-Cehic, Josep Gregori, Celia Perales, Laura Ordeig, Meritxell Llorens, Maria Eugenia Soria, Rafael Esteban, Juan Ignacio Esteban, Francisco Rodriguez-Frias, Josep Quer
AIM: To develop a fast, low-cost diagnostic strategy to identify single point mutations in highly variable genomes such as hepatitis C virus (HCV). METHODS: In patients with HCV infection, resistance-associated amino acid substitutions within the viral quasispecies prior to therapy can confer decreased susceptibility to direct-acting antiviral agents and lead to treatment failure and virological relapse. One such naturally occurring mutation is the Q80K substitution in the HCV-NS3 protease gene, which confers resistance to PI inhibitors, particularly simeprevir...
November 21, 2016: World Journal of Gastroenterology: WJG
keyword
keyword
52030
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"