Browsing by Subject "Phylogenetic analysis"

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    Development of Hepatitis C Virus Genotyping by Real-Time PCR Based on the NS5B Region
    (Public Library of Science, 2010-04-13) Nakatani, Sueli M.; Santos, Carlos A.; Riediger, Irina N.; Krieger, Marco A.; Duarte, Cesar A. B.; Lacerda, Marco A.; Biondo, Alexander W.; Carilho, Flair J.; Ono-Nita, Suzane K.; Medicine, School of Medicine
    Hepatitis C virus (HCV) genotyping is the most significant predictor of the response to antiviral therapy. The aim of this study was to develop and evaluate a novel real-time PCR method for HCV genotyping based on the NS5B region. Methodology/Principal Findings Two triplex reaction sets were designed, one to detect genotypes 1a, 1b and 3a; and another to detect genotypes 2a, 2b, and 2c. This approach had an overall sensitivity of 97.0%, detecting 295 of the 304 tested samples. All samples genotyped by real-time PCR had the same type that was assigned using LiPA version 1 (Line in Probe Assay). Although LiPA v. 1 was not able to subtype 68 of the 295 samples (23.0%) and rendered different subtype results from those assigned by real-time PCR for 12/295 samples (4.0%), NS5B sequencing and real-time PCR results agreed in all 146 tested cases. Analytical sensitivity of the real-time PCR assay was determined by end-point dilution of the 5000 IU/ml member of the OptiQuant HCV RNA panel. The lower limit of detection was estimated to be 125 IU/ml for genotype 3a, 250 IU/ml for genotypes 1b and 2b, and 500 IU/ml for genotype 1a. Conclusions/Significance The total time required for performing this assay was two hours, compared to four hours required for LiPA v. 1 after PCR-amplification. Furthermore, the estimated reaction cost was nine times lower than that of available commercial methods in Brazil. Thus, we have developed an efficient, feasible, and affordable method for HCV genotype identification.
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    Diversity and Complexity of the Large Surface Protein Family in the Compacted Genomes of Multiple Pneumocystis Species
    (American Society for Microbiology, 2020-03-03) Ma, Liang; Chen, Zehua; Huang, Da Wei; Cissé, Ousmane H.; Rothenburger, Jamie L.; Latinne, Alice; Bishop, Lisa; Blair, Robert; Brenchley, Jason M.; Chabé, Magali; Deng, Xilong; Hirsch, Vanessa; Keesler, Rebekah; Kutty, Geetha; Liu, Yueqin; Margolis, Daniel; Morand, Serge; Pahar, Bapi; Peng, Li; Van Rompay, Koen K.A.; Song, Xiaohong; Song, Jun; Sukura, Antti; Thapar, Sabrina; Wang, Honghui; Weissenbacher-Lang, Christiane; Xu, Jie; Lee, Chao-Hung; Jardine, Claire; Lempicki, Richard A.; Cushion, Melanie T.; Cuomo, Christina A.; Kovacs, Joseph A.; Pathology and Laboratory Medicine, School of Medicine
    Pneumocystis, a major opportunistic pathogen in patients with a broad range of immunodeficiencies, contains abundant surface proteins encoded by a multicopy gene family, termed the major surface glycoprotein (Msg) gene superfamily. This superfamily has been identified in all Pneumocystis species characterized to date, highlighting its important role in Pneumocystis biology. In this report, through a comprehensive and in-depth characterization of 459 msg genes from 7 Pneumocystis species, we demonstrate, for the first time, the phylogeny and evolution of conserved domains in Msg proteins and provide a detailed description of the classification, unique characteristics, and phylogenetic relatedness of five Msg families. We further describe, for the first time, the relative expression levels of individual msg families in two rodent Pneumocystis species, the substantial variability of the msg repertoires in P. carinii from laboratory and wild rats, and the distinct features of the expression site for the classic msg genes in Pneumocystis from 8 mammalian host species. Our analysis suggests multiple functions for this superfamily rather than just conferring antigenic variation to allow immune evasion as previously believed. This study provides a rich source of information that lays the foundation for the continued experimental exploration of the functions of the Msg superfamily in Pneumocystis biology.
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    Multi-region Whole Exome Sequencing of Intraductal Papillary Mucinous Neoplasms Reveals Frequent Somatic KLF4 Mutations Predominantly in Low-Grade Regions
    (BMJ, 2021) Fujikura, Kohei; Hosoda, Waki; Felsenstein, Matthäus; Song, Qianqian; Reiter, Johannes G.; Zheng, Lily; Guthrie, Violeta Beleva; Rincon, Natalia; Molin, Marco Dal; Dudley, Jonathan; Cohen, Joshua D.; Wang, Pei; Fischer, Catherine G.; Braxton, Alicia M.; Noë, Michaël; Jongepier, Martine; Castillo, Carlos Fernández-del; Mino-Kenudson, Mari; Schmidt, C. Max; Yip-Schneider, Michele T.; Lawlor, Rita T.; Salvia, Roberto; Roberts, Nicholas J.; Thompson, Elizabeth D.; Karchin, Rachel; Lennon, Anne Marie; Jiao, Yuchen; Wood, Laura D.; Surgery, School of Medicine
    Objective: Intraductal papillary mucinous neoplasms (IPMNs) are non-invasive precursor lesions that can progress to invasive pancreatic cancer and are classified as low-grade or high-grade based on the morphology of the neoplastic epithelium. We aimed to compare genetic alterations in low-grade and high-grade regions of the same IPMN in order to identify molecular alterations underlying neoplastic progression. Design: We performed multiregion whole exome sequencing on tissue samples from 17 IPMNs with both low-grade and high-grade dysplasia (76 IPMN regions, including 49 from low-grade dysplasia and 27 from high-grade dysplasia). We reconstructed the phylogeny for each case, and we assessed mutations in a novel driver gene in an independent cohort of 63 IPMN cyst fluid samples. Results: Our multiregion whole exome sequencing identified KLF4, a previously unreported genetic driver of IPMN tumorigenesis, with hotspot mutations in one of two codons identified in >50% of the analyzed IPMNs. Mutations in KLF4 were significantly more prevalent in low-grade regions in our sequenced cases. Phylogenetic analyses of whole exome sequencing data demonstrated diverse patterns of IPMN initiation and progression. Hotspot mutations in KLF4 were also identified in an independent cohort of IPMN cyst fluid samples, again with a significantly higher prevalence in low-grade IPMNs. Conclusion: Hotspot mutations in KLF4 occur at high prevalence in IPMNs. Unique among pancreatic driver genes, KLF4 mutations are enriched in low-grade IPMNs. These data highlight distinct molecular features of low-grade and high-grade dysplasia and suggest diverse pathways to high-grade dysplasia via the IPMN pathway.