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目的研究CTXΦ是否可以在没有TLC(toxin-linked cryptic)因子的非产毒霍乱弧菌染色体上整合,以及是否可以在霍乱弧菌小染色体上整合。方法筛选染色体上没有整合CTXΦ及TLC基因组的霍乱菌株(CTX-TLC-),检测这类菌株染色体上是否有类似的CTXΦ染色体整合位点attB。以含有CTXΦ的RS区及整合位点的自杀质粒pKRSn与pKRSe结合转移到CTX-TLC-及CTX- TLC+菌株,观察染色体整合情况,并分析整合位置的序列。结果CTX-TLC-菌株存在与CTXΦ染色体整合位点相似的序列。在CTX+TLC-菌株当中,CTXΦ基因组存在于小染色体上。自杀质粒pKRSn与pKRSe可以在TLC+及TLC-菌株的大染色体发生整合,也可以在TLC-菌株的小染色体发生整合。结论CTXΦ可以在霍乱弧菌的两条染色体上通过高度相似或一致的attB位点发生整合,另外也提示TLC在CTXΦ的大染色体整合中可能发挥作用。
Objective To investigate whether CTXΦ can be integrated on chromosomes of non-toxigenic V. cholerae without TLC, and whether it can be integrated in cholera of V. cholera. Methods Cholera strains (CTX-TLC-) that did not integrate CTXΦ and TLC genomes were screened for the presence of a similar CTXΦ chromosomal integration site attB on these chromosomes. The suicide plasmid pKRSn containing the RS region and integration site of CTXΦ was combined with pKRSe to transfer CTX-TLC- and CTX-TLC + strains. The chromosomal integration was observed and the sequence of the integration site was analyzed. Results The sequence of CTX-TLC-strain was similar to CTXΦ chromosomal integration site. Among the CTX + TLC-strains, the CTXΦ genome is present on small chromosomes. Suicide plasmids pKRSn and pKRSe can integrate on the TLC + and the large chromosomes of the TLC-strain, as well as on the small chromosome of the TLC-strain. Conclusion CTXΦ can be integrated on two chromosomes of Vibrio cholerae by highly similar or consistent attB sites. It also suggests that TLC may play a role in the integration of chromosomes in CTXΦ.