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目的 研究霍乱弧菌中不携带霍乱毒素基因的溶原性噬菌CTXΦ基因组 (nct CTXclassΦ)的RS区的复制与整合功能。方法 将这种噬菌体基因组的RS区克隆到不能在霍乱弧菌中复制的自杀质粒载体中 ,经接合转入含CTXΦ的整合位点attRS、但不含CTXΦ基因组的O1群ElTor型和O139群菌株中 ,分析含RS的重组自杀质粒在这些被接合菌株中的存在形式。结果 克隆了RS区的重组自杀质粒高频接合入受体菌中 ,在这些被接合菌株中既发生了染色体整合 ,同时又以质粒的形式存在于菌细胞内。结论 霍乱弧菌不携带霍乱毒素基因的CTXΦ基因组的RS区仍具有整合与质粒复制功能 ,可介导该基因组的复制与染色体整合。
OBJECTIVE: To study the replication and integration of the RS region of the lymphotropic phage CTXΦ genome carrying no cholera toxin gene in V. cholerae. Methods The RS region of this bacteriophage genome was cloned into a suicide plasmid vector that could not be replicated in V. cholerae, ligated into attRS containing CTXΦ but not to CTXΦ genome, and strains of O139 ElTor and O139 , The presence of RS-containing recombinant suicide plasmids in these mated strains was analyzed. Results Recombinant suicide plasmids cloned in the RS region were high-frequency conjugated into the recipient bacteria. Chromosomal integration occurred in these conjugate strains, and at the same time they were present in the bacterial cells in the form of plasmids. Conclusion The RS region of Vibrio cholerae CTXΦ genome that does not carry the cholera toxin gene still has the function of integration and plasmid replication and can mediate the replication and chromosomal integration of the genome.