Dimethyl adenosine transferase (KsgA) contributes to cell-envelope fitness in Salmonella Enteritidis.
Dimethyl adenosine transferase (KsgA) contributes to cell-envelope fitness in Salmonella Enteritidis.
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DOI：
10.1016/j.micres.2018.08.009
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发表时间：
2018-11
影响因子：
6.7
通讯作者：
Shah DH
中科院分区：
文献类型：
--
作者：
Chiok KL;Paul NC;Adekanmbi EO;Srivastava SK;Shah DH
我们之前报道了普遍保守的二甲基腺苷转移酶（KsgA）的失活可降低肠炎沙门氏菌的毒力并增加对氧化和渗透应激的敏感性。在这里，我们展示了KsgA在细胞包膜适应性中的作用，作为沙门氏菌这些表型的潜在机制。我们通过透射电子显微镜评估了肠球菌野生型和ksgA敲除突变体的细胞包膜结构完整性，通过测定细胞内溴化乙啶的积累来评估了通透性屏障功能，并通过电介质电泳（一种电动工具）评估了电物理特性。ksgA的缺失导致细胞包膜结构完整性、渗透性屏障和电物理性质的破坏。野生型KsgA （WT-ksgA）的表达减轻了细胞包膜适应性缺陷，而其催化失活形式ksgAE66A的表达则不能减轻细胞包膜适应性缺陷，这表明KsgA的二甲基转移酶活性对肠炎沙门氏菌的细胞包膜适应性很重要。WT-ksgA和ksgAE66A在固有渗透性大肠杆菌细胞中表达后，前者增强了渗透性屏障，后者减弱了渗透性屏障，表明KsgA也有助于大肠杆菌的细胞包膜适应性。最后，ksgAE66A的表达加重了细胞包膜适应度缺陷，导致肠炎沙门氏菌与人肠上皮细胞、人和禽吞噬细胞的相互作用受损。本研究表明KsgA有助于细胞包膜适应性，并通过使用KsgA拮抗剂开辟了调节细胞包膜的新途径。
We previously reported that inactivation of a universally conserved dimethyl adenosine transferase (KsgA) attenuates virulence and increases sensitivity to oxidative and osmotic stress in Salmonella Enteritidis. Here, we show a role of KsgA in cell-envelope fitness as a potential mechanism underlying these phenotypes in Salmonella. We assessed structural integrity of the cell-envelope by transmission electron microscopy, permeability barrier function by determining intracellular accumulation of ethidium bromide and electrophysical properties by dielectrophoresis, an electrokinetic tool, in wild-type and ksgA knock-out mutants of S. Enteritidis. Deletion of ksgA resulted in disruption of the structural integrity, permeability barrier and distorted electrophysical properties of the cell-envelope. The cell-envelope fitness defects were alleviated by expression of wild-type KsgA (WT-ksgA) but not by its catalytically inactive form (ksgAE66A), suggesting that the dimethyl transferase activity of KsgA is important for cell-envelope fitness in S. Enteritidis. Upon expression of WT-ksgA and ksgAE66A in inherently permeable E. coli cells, the former strengthened and the latter weakened the permeability barrier, suggesting that KsgA also contributes to the cell-envelope fitness in E. coli. Lastly, expression of ksgAE66A exacerbated the cell-envelope fitness defects, resulting in impaired S. Enteritidis interactions with human intestinal epithelial cells, and human and avian phagocytes. This study shows that KsgA contributes to cell-envelope fitness and opens new avenues to modulate cell-envelopes via use of KsgA-antagonists.
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影响因子：
30.3
作者：
Dalebroux, Zachary D.;Edrozo, Mauna B.;Miller, Samuel I.
通讯作者：
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影响因子：
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作者：
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DOI：
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发表时间：
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通讯作者：
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