O139群霍乱弧菌染色体中整合两种CTXΦ前噬菌体基因组的多样性  

Two different CTXΦ prophage genomes present on the chromosomes of Vibrio cholerae serogroup O139 strains and multiformity of their concomitance

作　　者：陈爱平[1] 阚飙[2] 陈拱立[1] 陈亢川[1] 刘延清[2] 

机构地区：[1]福建省卫生防疫站 [2]中国预防医学科学院流行病学微生物学研究所.卫生部医学分子细菌学重点实验室

出　　处：《中华微生物学和免疫学杂志》2002年第3期239-242,共4页Chinese Journal of Microbiology and Immunology

基　　金：国家自然科学基金资助项目 (39870 0 31 );福建省卫生厅青年科学基金项目 (98 1 1 5)

摘　　要：目的　研究同时携带两种CTXΦ基因组的O139群霍乱弧菌中CTXΦ基因组的多样性。方法　Southernblot检测分离自福建的部分O139霍乱弧菌菌株中ctxAB和zot基因的多态性 ,然后选取ctxAB和zot基因拷贝数差异较大的 3株菌 ,扩增其调控抑制基因rstR基因片段 ,克隆并进行序列测定、分析。结果　此 3株菌染色体zot杂交条带多于ctxAB 2～ 5条 ,提示 1个菌株染色体上有编码ctxAB的CTXΦ以及不编码ctxAB的CTXΦ两种基因组。以保守区设计的引物扩增此 3株菌的rstR区 ,均得到 2条大小不同的条带 ,分别克隆后进行测序 ,经GenBank同源性检索 ,发现在此 3个菌株染色体中分别有来自ElTor型的CTXETΦ与不编码ctxAB的nct CTXO13 9Φ、来自加尔各答型的CTXcalcΦ与nct CTXO13 9Φ、以及CTXETΦ与新报道的一种具有独特rstR序列的CTXΦ类基因组两两共存于 1个菌株染色体上。这 3个菌株还具有不同的 16S核糖体基因杂交图谱。结论　不同rstR序列的CTXΦ基因组可以共存于 1个菌株染色体中 ,提示CTXΦ家族进化过程中的复杂分化 ,CTXΦ家族在不同霍乱菌株间的出现及传递。Objective To study the diversity of bacteriophage CTXΦ genomes in serogroup O139 strains of Vibrio cholerae that harbored two types of CTXΦ genome. Methods Some strains with distinct variance in copy number of ctxAB and zot of CTXΦ were detected by Southern blot and selected as the templets, fragments containing the suppressor gene rstR were amplified, sequenced and analysed. Results The rstR containing fragments which were amplified with primers designed according to the conservative regions presented two different amplicons in length with these strains, implying that two types of CTXΦ genomes coexist in the chromosome of the 3 strains, i.e., one CTXΦ genome that encodes ctxAB, and another CTXΦ genome without ctxAB. These amplicons were further cloned and sequenced. By homology searching in GenBank, three different co existence of CTXΦ genomes in the 3 strains were found. Conclusion Different CTXΦ genomes with different sequence of rstR coexist in the same strain. The complexity in the process of evolution in the CTXΦ family and the appearance, transfer of CTXΦ family in various serogroups or biotypes of V.cholerae may show divergence of V.cholerae strains. [

关 键 词：噬菌体 CTXφ基因组 基因多态性 O139群霍乱弧菌 染色体 

分 类 号：R378.3[医药卫生—病原生物学]