Association between angiotensin-converting enzyme and polymorphisms of N5, N10-methylenetetrahydrofolic acid reductase gene in patients with ischemic stroke / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the association between angiotensin-converting enzyme (ACE) and the polymorphisms of N5, N10-methylenetetrahydrofolic acid reductase (MTHFR) gene in patients with ischemic stroke (IS).</p><p><b>METHODS</b>Totally 454 patients with IS (IS group) and 334 controls (control group) were recruited in our study. Their I/D polymorphisms of ACE gene and C677T polymorphisms of MTHFR gene were detected by PCR and denaturing high performance liquid chromatography.</p><p><b>RESULTS</b>The frequencies of DD, ID, II and CC, CT, TT genotype in IS group were 22.5%, 43.4%, 34.1%, and 51.8%, 40.5%, 7.7%, respectively, and were 17.4%, 45.5%, 37.1% and 56.9%, 38.3%, 4.8% in the control group, respectively. DD genotype was associated with large-artery atherosclerosis (LAA), and TT genotype and T allele were associated with LAA and cardioembolism. Synergistic effects were found between TT and DD/ID DD genotypes in the pathogenesis of ischemic stroke.</p><p><b>CONCLUSION</b>DD, TT genotype and T allele are risk factors of IS, and ACE gene and MTHFR gene have synergistic effects in the pathogenesis of IS.</p>

Detecting the polymorphism of methylenetetrahydrofolate reductase gene by denaturing high performance liquid chromatography / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To establish a method for detecting the polymorphism of methylenetetrahydrofolate reductase gene (MTHFR).</p><p><b>METHODS</b>The MTHFR was amplified, and the amplified products were detected by denaturing high performance liquid chromatography (DHPLC), and the amplified MTHFR was confirmed by sequencing and restriction enzyme digesting.</p><p><b>RESULTS</b>A total of 334 individuals of Han people in southern China were recruited in our study, and their polymorphisms of MTHFR were detected. The accurate rate of the DHPLC method, that was very sensitive with 100% detection rate available, was over 99%. The frequencies of CC, CT and TT genotypes were 56.9%, 38.3% and 4.8% individually, and the frequencies of T and C alleles were 23.95% and 76.05% individually.</p><p><b>CONCLUSION</b>The DHPLC method can detect polymorphism of MTHFR rapidly, effectively and economically. And there is the existence of different MTHFR polymorphisms in area and race.</p>

Expression of xylanase gene xynA from Streptomyces olivaceoviridis A1 in Escherichia coli and Pichia pastoris / 生物工程学报

The gene xynA encoding xylanase was cloned from Streptomyces olivaceoviridis A1. The xynA with and without origin signal peptide sequence were fused behind pel B signal peptide in the plasmid pET-22b(+) respectively, then transfered into the host E. coli. The xylanase expressed in E. coli had normal bioactivity. Further, the xynA without origin signal peptide sequence was cloned into the plasmid pPIC9 under the control of AOX1 promoter and introduced into the host Pichia pastoris by electroporation. The results of SDS-PAGE and activity assay of the xylanase expressed by recombinant P. pastoris showed that the xynA had been overexpressed and secreted, and the xylanase expressed had normal bioactivity. The expression level of xylanase in recombinant P. pastoris exceeded 0.2mg/mL in shake culture.