Ramirez M, Morrison D A, Tomasz A
Laboratory of Microbiology, Rockefeller University, New York, New York 10021, USA.
Microb Drug Resist. 1997 Spring;3(1):39-52. doi: 10.1089/mdr.1997.3.39.
DNA probes specific for the pneumococcal competence regulatory genes comA and comC were used to test the presence of these genes in 214 pneumococcal isolates selected to represent a wide variety of clonal types and genetic backgrounds (as defined by chromosomal macrorestriction patterns and multilocus enzyme analysis), a variety of serotypes, isolation dates (between 1916 and 1996), geographic origins (on four continents), as well as different clinical origins (including both infection sites and colonization sites). Each isolate gave positive signal with both DNA probes. The comA and comC genes were never on the same SmaI restriction fragment and the comA gene showed a considerable degree of polymorphism from one strain to another. While DNA sequencing of 50 of the isolates have identified three distinct alleles of the comC gene, the number of mutations within the leader peptide were minimal. The results suggest that the mechanism to undergo genetic transformation is widespread within the species of Streptococcus pneumoniae.
使用针对肺炎球菌感受态调节基因comA和comC的DNA探针，检测了214株肺炎球菌分离株中这些基因的存在情况。这些分离株经过挑选，代表了广泛的克隆类型和遗传背景（由染色体宏观限制性图谱和多位点酶分析定义）、多种血清型、分离日期（1916年至1996年之间）、地理来源（四大洲）以及不同的临床来源（包括感染部位和定植部位）。每株分离株与两种DNA探针均产生阳性信号。comA和comC基因从未位于同一SmaI限制性片段上，并且comA基因在不同菌株之间表现出相当程度的多态性。虽然对50株分离株进行DNA测序已鉴定出comC基因的三个不同等位基因，但前导肽内的突变数量极少。结果表明，进行遗传转化的机制在肺炎链球菌物种中广泛存在。
