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目的 了解细胞壁缺陷肺炎链球菌青霉素结合蛋白2b基因(pbp2b)片段的检测及其意义.方法 用青霉素诱导肺炎链球菌形成L型,分离稳定L型纯培养物.提取L型染色体DNA,用肺炎链球菌pbp2b序列特异性引物进行聚合酶链式反应(PCR)并检测扩增产物的核苷酸序列,测得序列与GenBank公布的肺炎链球菌R6菌株种特异性pbp2b(628 bp)序列比对.结果 肺炎链球菌稳定L型PCR扩增产物的核苷酸序列与肺炎链球菌R6菌株种特异性pbp2b序列具有99.1%的同源性.结论 细胞壁缺陷肺炎链球菌保留了与肺炎链球菌R6菌株高度同源的种特异性pbp2b基因片段,检测该基因片段可用于肺炎链球菌稳定L型的鉴定.“,”Objective To evaluate the detection and significance of specids specific pbp2b gene fragment of the L-form of S.pneurnoniae.Methods L-form of S.pneumoniae was induced by penicilin in the non-high osmotic medium and the pure cultures of stable L-form were isolated and subcuhured in the non-high osmotic medium without any antibiotics.The chromosome DNAs of the pure cultures of stable L-form were isolated and then the pbp2b gene was amplified with the penicillin-binding protein 2b(pbp2b)gene-specific PCR primers.The production of PCR was detected by nucleotide sequencing analysis.The DNA sequence of L-form detected was compared with the specids specific pbp2b(682 bp)sequence of S.pneumoniae R6 strain published at GenBank.Results The DNA secquence of stable L-form of S.pneumoniae had 99.1% homology contrasting with the specids specific pbp2b sequence of S.pneumoniae R6 strain.Conclusion The high homology of specids specific pbp2b gene fragment of S.pneumoniae is retained in stable L-form of S.pneumoniae and it could be used for the identification of stable L-form of S.pneumoniae.