An approach for determination of hepatitis C virus (HCV) quasispecies by end-point limiting-dilution real-time PCR (EPLD-PCR) is described. It involves isolation of individual coexisting sequence variants of the hypervariable region 1 (HVR1) of the HCV genome from serum specimens using a limiting-dilution protocol. EPLD-PCR applied to an HCV outbreak study provided insights into the epidemiological relationships between incident and chronic cases. When applied to samples from a longitudinal study of infected patients, HVR1 sequences from each sampling time-point were observed to group as distinct phylogenetic clusters. Melting peak analysis conducted on EPLD-PCR products generated from these patients could be used for evaluation of HVR1 sequence heterogeneity without recourse to clonal sequencing. Further, to better understand the mechanism of single-molecule PCR, experiments were conducted under optimal and suboptimal annealing temperatures. Under all temperature conditions tested, HVR1 variants from the major phylogenetic clusters of quasispecies could be amplified, revealing that successful HVR1 quasispecies analysis is not contingent to dilution of starting cDNA preparations to a single-molecule state. It was found that EPLD-PCR conducted at suboptimal annealing temperatures generated distributions of unique-sequence variants slightly different from the distribution obtained by PCR conducted at the optimal temperature. Hence, EPLD-PCR conditions can be manipulated to access different subpopulations of HCV HVR1 quasispecies, thus, improving the range of the quasispecies detection. Although EPLD-PCR conducted at different conditions detect slightly different quasispecies populations, as was shown in this study, the resulted samples of quasispecies are completely suitable for molecular epidemiological investigation in different clinical and epidemiological settings.
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http://dx.doi.org/10.1016/j.jviromet.2008.05.005 | DOI Listing |
Anal Bioanal Chem
May 2018
Statistical Engineering Division, Information Technology Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8380, Gaithersburg, MD, 20899-8980, USA.
The highly multiplexed polymerase chain reaction (PCR) assays used for forensic human identification perform best when used with an accurately determined quantity of input DNA. To help ensure the reliable performance of these assays, we are developing a certified reference material (CRM) for calibrating human genomic DNA working standards. To enable sharing information over time and place, CRMs must provide accurate and stable values that are metrologically traceable to a common reference.
View Article and Find Full Text PDFForensic Sci Int Genet
March 2017
Institute of Microbiology and Immunology, University of Belgrade School of Medicine, Belgrade, Serbia. Electronic address:
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.
View Article and Find Full Text PDFAnal Chem
February 2016
Materials Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8390, United States.
Polymerase chain reaction (PCR) multiplexed assays perform best when the input quantity of template DNA is controlled to within about a factor of √2. To help ensure that PCR assays yield consistent results over time and place, results from methods used to determine DNA quantity need to be metrologically traceable to a common reference. Many DNA quantitation systems can be accurately calibrated with solutions of DNA in aqueous buffer.
View Article and Find Full Text PDFJ Infect Dis
March 2016
University of British ColumbiaBC Centre for Disease Control, Vancouver, Canada.
J Infect Dis
March 2016
Molecular Epidemiology and Bioinformatics Laboratory, Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, Georgia.
Hepatitis C is a major public health problem in the United States and worldwide. Outbreaks of hepatitis C virus (HCV) infections are associated with unsafe injection practices, drug diversion, and other exposures to blood and are difficult to detect and investigate. Here, we developed and validated a simple approach for molecular detection of HCV transmissions in outbreak settings.
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