McGowan C C, Necheva A, Thompson S A, Cover T L, Blaser M J
Department of Medicine, Vanderbilt University Medical School, and Department of Veterans Affairs Medical Center, Nashville, TN, USA.
Mol Microbiol. 1998 Oct;30(1):19-31. doi: 10.1046/j.1365-2958.1998.t01-1-01079.x.
To investigate urease-independent mechanisms by which Helicobacter pylori resists acid stress, subtractive RNA hybridization was used to identify H. pylori genes whose expression is induced after exposure to acid pH. This approach led to the isolation of a gene that encoded a predicted 34.8kDa protein (WbcJ), which was homologous to known bacterial O-antigen biosynthesis proteins involved in the conversion of GDP-mannose to GDP-fucose. An isogenic wbcJ null mutant strain failed to express O-antigen and Lewis X or Lewis Y determinants and was more sensitive to acid stress than was the wild-type strain. Qualitative differences in LPS profiles were observed in H. pylori cells grown at pH 5 compared with pH 7, which suggests that H. pylori may alter its LPS structure in response to acidic pH. This may be an important adaptation facilitating H. pylori colonization of the acidic gastric environment.
为了研究幽门螺杆菌抵抗酸应激的不依赖脲酶的机制，采用消减RNA杂交技术来鉴定幽门螺杆菌中在暴露于酸性pH后表达被诱导的基因。该方法导致分离出一个编码预测分子量为34.8kDa的蛋白质（WbcJ）的基因，该蛋白质与已知的参与GDP-甘露糖向GDP-岩藻糖转化的细菌O抗原生物合成蛋白同源。一个同基因的wbcJ缺失突变株未能表达O抗原以及Lewis X或Lewis Y决定簇，并且比野生型菌株对酸应激更敏感。与在pH 7条件下生长的幽门螺杆菌细胞相比，在pH 5条件下生长的幽门螺杆菌细胞的脂多糖（LPS）谱存在定性差异，这表明幽门螺杆菌可能会响应酸性pH改变其LPS结构。这可能是促进幽门螺杆菌在酸性胃环境中定殖的重要适应性变化。
