The effects of low-shear stress on Adherent-invasive Escherichia coli
The effects of low-shear stress on Adherent-invasive Escherichia coli
复制标题
DOI：
10.1111/j.1462-2920.2008.01567.x
复制
发表时间：
2008-06-01
影响因子：
5.1
通讯作者：
Torres, Alfredo G.
中科院分区：
文献类型：
--
作者：
Allen, Christopher A.;Niesel, David W.;Torres, Alfredo G.
评价了低剪切应力（LSS）对来自克罗恩病患者的粘附侵袭性大肠杆菌临床分离株（AIEC菌株O 83：H1）的影响。使用高纵横比血管（HARV）来模拟LSS条件，以表征环境应力抵抗力和粘附/侵入特性的变化。低剪切应力生长的培养物表现出增强的耐热性和抗氧化应激性，以及增加的粘附Caco-2细胞，但没有观察到入侵的变化。构建AIEC rpoS突变体以检查这种全局压力调节剂的影响。LSS条件下RpoS的缺乏导致对氧化应激的敏感性增加，而与野生型菌株相比，粘附水平升高。对rpoS突变体进行TnphoA诱变和rpoS互补，以鉴定参与LSS诱导的粘附表型的那些因子。突变结果表明，一个插入破坏tnaB基因（编码色氨酸通透酶）和rpoS tnaB双突变体表现出降低LSS下的粘附。补充tnaB基因，或培养基中补充外源性吲哚，恢复粘附的rpoS tnaB突变体在LSS条件下。总的来说，我们的研究证明了LSS等机械应力如何改变AIEC的表型特征，并确定了一些Rpos调节蛋白的新功能。
The impact of low-shear stress (LSS) was evaluated on an Adherent-invasive Escherichia coli clinical isolate (AIEC strain O83:H1) from a Crohn's disease patient. High-aspect ratio vessels (HARVs) were used to model LSS conditions to characterize changes in environmental stress resistance and adhesion/invasive properties. Low-shear stress-grown cultures exhibited enhanced thermal and oxidative stress resistance as well as increased adherence to Caco-2 cells, but no changes in invasion were observed. An AIEC rpoS mutant was constructed to examine the impact of this global stress regulator. The absence of RpoS under LSS conditions resulted in increased sensitivity to oxidative stress while adherence levels were elevated in comparison with the wild-type strain. TnphoA mutagenesis and rpoS complementation were carried out on the rpoS mutant to identify those factors involved in the LSS-induced adherence phenotype. Mutagenesis results revealed that one insertion disrupted the tnaB gene (encoding tryptophan permease) and the rpoS tnaB double mutant exhibited decreased adherence under LSS. Complementation of the tnaB gene, or medium supplemented with exogenous indole, restored adhesion of the rpoS tnaB mutant under LSS conditions. Overall, our study demonstrated how mechanical stresses such as LSS altered AIEC phenotypic characteristics and identified novel functions for some RpoS-regulated proteins.