摘要
本文利用 RP_1质粒的温度敏感突变体 pMR_5::Tn_(132)的温敏特性,以及 pMR_5::Tn_(132)上所携带的转座子 Tn_(132)与宋内氏Ⅰ相大质粒 pSS_(120)::Tn_5上转座子 Tn_5两端插入序列的同源性,将 Tn_5置换成 Tn_(132),从而将 pSS_(120)::Tn_5携带的卡那霉素抗性换成了 Tn_(132)所携带的四环素抗性,进而又在 Bochner 培养基上选到了四环素敏感的突变体,得到了宋内氏Ⅰ相大质粒 pSS_(120)上无任何抗药性标记的宋内氏福氏2a 双价痢疾菌株。
pMR_5Tn_(132) plasmid is one of the temperature-sensitive derivatives of RP_1 which belongs to P incompatibility group.Tn_(132) is a derivative transposon of Tn_5,it bears the same insertion sequences as Tn_5 flanking at two ends.Tn_(132) carries tetracycline-resistant gene instead of kanamycine one.In this paper,depending upon the temperature-sensitivity of pMR_5Tn_(132) and the homology between Tn_(132) on pMR_5Tn_(132) and Tn_5 on pSS_(120) Tn_5,we successfully replaced the Tn_5 on pSS_(120)Tn_5 with Tn_(132).As a concequence,the pSS_(120)Tn_(132) expressed tetracycline resistance instead of kanamycine resistance.Furtherm- ore,we successfully selected out tetracycline-sensitive mutants of pSS_(120)Tn_(132) on Bochner medium.Thus we obtained the bivalent hybrid strain FS54-7 of Sh.sonneiand Sh.flexneri 2a,in which the pSS_(120) don't bear any drug-resistant gene.
出处
《军事医学科学院院刊》
CSCD
北大核心
1990年第3期188-192,共5页
Bulletin of the Academy of Military Medical Sciences
