Study on the expression of telomerase RNA in leukocyte / 生物医学工程学杂志

Total cDNA of human telomerase RNA(hTR) gene was cloned by means of RT-PCR and inverted into retroviral vector (pLNCX) to construct the mammalian cell expression plasmid. Then, by using lipofectin-mediated DNA transfection, the obtained expression plasmid was successfully transfected into human normal peripheral blood leukocyte. All data suggested that expression of transfected exogenous hTR gene can not reconstitute telomerase activity. Flow cytometry analysis and data from cell growth curve also indicated that expression of exogenous gene can not prolong the longevity of leukocyte, but rather inhibit the growth of leukocyte and induce its apoptosis. We conclude that expression of exogenous gene may block the coalition of telomerase RNA and its catalytic subunit(hTRT) and block the coalition of telomerase RNA template and telomere DNA, thus affecting telomerase activity and repressing cell proliferation.

DNA Typing of Sporothrix schenckii by Analysis of Ribosomal-DNA Regions / 中华皮肤科杂志

Objectives To identify genotypes of 31 Sporothrix schenckii (S.schenckii) strains by Southern blotting and to explore the relationship between genotypes and geographic distributions and clinical manifestations.Methods Total DNA was extracted by cetyltriethyl ammonium bromide (CTAB).The polymorphisms were detected by hybridization of ApaⅠ-digested S.schenckii genomic DNA with a probe amplified from the small-subunit rDNA and adjacent internal transcribed spacer (ITS) regions.The band patterns manifested by Southern blotting were employed to investigate genotypes of 31 strains of S.schenckii collected from five different areas in China.Results Of 31 strains of S.schenckii,15 individual patterns (DNA Type A-O) were recognized.Type A to C accounted for 51.61% of all strains.Conclusion The Southern blotting provides a highly sensitive and reliable means for DNA typing of S.schenckii.It is also found that there is an obvious correlation between DNA patterns and different geographic distribution and clinical manifestations.

Characterization of Sporothrix schenckii by random amplification of polymorphic DNA assay / 中华医学杂志(英文版)

<p><b>OBJECTIVES</b>To investigate the DNA polymorphism of Sporothrix schenckii (S. schenckii) and to find the relationship between DNA patterns and geographic areas and clinical manifestations.</p><p><b>METHOD</b>The total DNA was extracted with hexadecyltrimethyl-ammonium bromide. Random Amplification of Polymorphic DNA (RAPD) assay was used to study DNA typing of 24 strains of S. schenckii collected from different areas and isolated from different clinical types.</p><p><b>RESULTS</b>Of seven random primers used, three primers (OPAA11, OPD18 and OPB07) gave good reactions, the sequences of which were 5'-ACCCGACCTG-3', 5'-GAGAGCCAAC-3', 5'-GGTGAC~GCAG-3' respectively. The RAPD patterns of the 24 isolates were not completely identical, showing certain degrees of hereditary variability. Different isolates showed a common conserved DNA band with the same primer. Different clinical types showed different genotypes.</p><p><b>CONCLUSION</b>RAPD analysis is useful in DNA typing of S. schenckii, the DNA band type of which is related to geographic origin and Clinical manifestation.</p>

Molecular Determination of Dermato phyte Fungi Using Arbitrarily Prime d Polymerase Chain Reaction / 中华皮肤科杂志

Objective To study the significance of AP-PCR i n identification and subtyping of der-matophytes.Methods Using a pair of random primers,OPAA11(5' -ACCCGACCTG -3' ),and OPD18(5' -GAGAGCCAAC -3' )the DNAs of 64isolates of dermatophytes(9species of 3genera),Sporothrix schenckii and Candida albicans were amplified by AP-PCR and analyse d by electrophoresis.Results Distinct DNA band patterns were observed in diffe rent dermatophyte species.Common major DNA bands were observed in Trichophyton rubrum isolated from different areas with s train difference.Conclusion Using OPAA11and OPD18as primers,AP-PCR may be applied in the identification and subtypi ng of dermatophytes.