Isolation of a genetic locus associated with metronidazole resistance in Helicobacter pylori
Isolation of a genetic locus associated with metronidazole resistance in Helicobacter pylori
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DOI：
10.1006/bbrc.1997.7050
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发表时间：
1997-07-30
影响因子：
3.1
通讯作者：
Wang, JT
中科院分区：
文献类型：
--
作者：
Chang, KC;Ho, SW;Wang, JT
我们用幽门螺杆菌甲硝唑耐药株基因组DNA构建了lambda-Zap II噬菌体表达文库，探讨了甲硝唑耐药的分子机制。在XLOLR菌株中，有22个克隆对甲氨蝶呤的抗性增强。提取了这22个克隆的噬菌体，并将其重新转化到XLOLR菌株中。MTZ筛选后，有5个克隆对甲硝唑具有一致的耐药性。根据Southern杂交和DNA测序，这5个克隆含有一个相同的基因座recA。此外，将这5个克隆转化到BL21菌株中，产生了对MTZ更高的抗性。有趣的是，将五个噬菌体克隆中的一个电穿孔到两个MTZ敏感的H.Pylori菌株中，获得了MTZ耐药株，将MTZ耐药株的氨基酸序列与敏感株进行比较，发现该基因有两个点突变。以上结果提示，recA突变可能与幽门螺杆菌对甲硝唑耐药有关。(C)1997年学术出版社。
We examined the molecular mechanism of metronidazole resistance by constructing a lambda-Zap II phagemid expression library with genomic DNA from a metronidazole-resistance strain of Helicobacter pylori. Twenty-two clones were found to have elevated MTZ resistances in XLOLR strain of E. coli. Phagemids belonging to the twenty two clones were extracted and then retransformed into the XLOLR strain of E. coli. After MTZ selection, five clones could confer metronidazole resistance consistently. According to Southern hybridization and DNA sequencing, the five clones contained a same locus, recA. In addition, transforming the five clones into BL21 strain of E. coli produced a higher resistance to MTZ. Interestingly, electroporation of one of the five phagemid clones into two MTZ sensitive H. pylori yielded MTZ resistant strains, Comparing amino acid sequence in MTZ resistant with sensitive isolates revealed two point mutations at this locus. Above results suggest that mutation in recA may be associated with metronidazole resistance of H. pylori. (C) 1997 Academic Press.