861 research outputs found

    Prevalence of Mycobacterium tuberculosis in Taiwan: A Model for Strain Evolution Linked to Population Migration

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    The global evolution and spread of Mycobacterium tuberculosis (MTB), one of the most successful bacterial pathogens, remain a mystery. Advances in molecular technology in the past decade now make it possible to understand MTB strain evolution and transmission in the context of human population migration. Taiwan is a relatively isolated island, serving as a mixing vessel over the past four centuries as colonization by different waves of ethnic groups occurred. By using mycobacterial tandem repeat sequences as genetic markers, the prevalence of MTB strains in Taiwan revealed an interesting association with historical migrations of different ethnic populations, thus providing a good model to explore the global evolution and spread of MTB

    Environmental and Occupational Health Response to SARS, Taiwan, 2003

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    Environmental and Occupational Health Industrial hygiene emergency response to SARS in Taiwan

    Low-cell-number, single-tube amplification (STA) of total RNA revealed transcriptome changes from pluripotency to endothelium

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    Table S1. Summary of the sequencing results. The alignments against the GRCh38 genome assembly (Aligned Reads) were counted for exon reads (exon) and transcript reads based on GENCODE v22. Intronic counts (intron) were defined by transcript counts minus exon ones. Nontranscript reads were used to obtain tRNA counts (tRNA) based on the tRNA database of GENCODE v22. Nontranscript and non-tRNA reads were used for counts on repetitive sequences (repeats) based on RepeatMasker. Those not belonging to any category were defined as unannotated reads (unannotated). The counting of exonic features was based on the “gene_type” attribute in GENCODE v22. The percentages of mature miRNA reads were defined by reads aligned exclusively to the mature “miRNA” feature divided by reads aligned to the “miRNA_primary_transcript” feature of miRBase v21. (DOCX 42 kb

    Introduction of a strong temperature-sensitive phenotype into enterovirus 71 by altering an amino acid of virus 3D polymerase

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    AbstractIn 1998, an enterovirus 71 (EV71) epidemic in Taiwan resulted in 78 deaths; however, the molecular basis of EV71 pathogenicity remains poorly understood. Comparison of the deduced amino acid sequences in 3D polymerases of EV71clinical isolates showed the T251V or T251I substitution from 1986 and 1998 outbreaks. An EV71 replicon system showed that introducing an I251T mutation did not affect luciferase activities at 35 °C when compared with wild type; however, lower luciferase activities were observed when they were incubated at 39.5 °C. In addition, the I251T mutation in the EV71 infectious clone not only reduced viral replication at 39.5 °C in vitro but also decreased the virulence of the mouse adaptive strain MP4 in neonatal mice in an i.p. infection model. Therefore, these results suggested that the threonine at position 251 results in a temperature sensitivity phenotype of EV71 which may contribute to the attenuation of circulating strains

    A pre-S gene chip to detect pre-S deletions in hepatitis B virus large surface antigen as a predictive marker for hepatoma risk in chronic hepatitis B virus carriers

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    <p>Abstract</p> <p>Background</p> <p>Chronic hepatitis B virus (HBV) infection is an important cause of hepatocellular carcinoma (HCC) worldwide. The pre-S<sub>1 </sub>and -S<sub>2 </sub>mutant large HBV surface antigen (LHBS), in which the pre-S<sub>1 </sub>and -S<sub>2 </sub>regions of the LHBS gene are partially deleted, are highly associated with HBV-related HCC.</p> <p>Methods</p> <p>The pre-S region of the LHBS gene in two hundred and one HBV-positive serum samples was PCR-amplified and sequenced. A pre-S oligonucleotide gene chip was developed to efficiently detect pre-S deletions in chronic HBV carriers. Twenty serum samples from chronic HBV carriers were analyzed using the chip.</p> <p>Results</p> <p>The pre-S deletion rates were relatively low (7%) in the sera of patients with acute HBV infection. They gradually increased in periods of persistent HBV infection: pre-S mutation rates were 37% in chronic HBV carriers, and as high as 60% in HCC patients. The Pre-S Gene Chip offers a highly sensitive and specific method for pre-S deletion detection and is less expensive and more efficient (turnaround time 3 days) than DNA sequencing analysis.</p> <p>Conclusion</p> <p>The pre-S<sub>1/2 </sub>mutants may emerge during the long-term persistence of the HBV genome in carriers and facilitate HCC development. Combined detection of pre-S mutations, other markers of HBV replication, and viral titers, offers a reliable predictive method for HCC risks in chronic HBV carriers.</p
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