Conflicting roles for a cell surface modification in Salmonella.
Conflicting roles for a cell surface modification in Salmonella.
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DOI：
10.1111/mmi.12236
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发表时间：
2013-06
影响因子：
3.6
通讯作者：
Groisman EA
中科院分区：
文献类型：
--
作者：
May JF;Groisman EA
细菌细胞膜成分的化学修饰可以增强对抗菌剂的抵抗力。那么，为什么只有在特定条件下才会产生这样的修改呢？在这里，我们通过研究O抗原长度的调节变化在脂多糖(LPS)中的作用来解决这个问题，脂多糖是一种糖脂，构成了革兰氏阴性细菌外膜的大部分外叶。我们确定，PmrA/PmrB双组分系统的激活损害了沙门氏菌在胆汁中的生长。PmrA/PmrB是肠道沙门氏菌内毒素变化的主要调节因素。这种生长缺陷需要PmrA激活的基因wzzst，它编码决定长O抗原链长度的蛋白质，并赋予对补体介导的杀伤的抵抗力。相比之下，这种生长缺陷并不需要wzzfepE基因，它控制着超长O抗原的产生，也不需要其他PmrA激活的基因来调节类脂A或内毒素核心区的修饰。此外，我们证实，只有在肠道细菌共同抗原存在的情况下，长O抗原才能抑制胆汁中的生长，肠道细菌共同抗原是一种促成胆汁抵抗的外膜糖脂。我们的结果表明，沙门氏菌调节其内毒素中长O抗原的比例，以应对感染过程中面临的不同条件。
Chemical modifications of components of the bacterial cell envelope can enhance resistance to antimicrobial agents. Why then are such modifications produced only under specific conditions? Here, we address this question by examining the role of regulated variations in O-antigen length in the lipopolysaccharide (LPS), a glycolipid that forms most of the outer leaflet of the outer membrane in Gram-negative bacteria. We determined that activation of the PmrA/PmrB two-component system, which is the major regulator of LPS alterations in Salmonella enterica serovar Typhimurium, impaired growth of Salmonella in bile. This growth defect required the PmrA-activated gene wzzst, which encodes the protein that determines long O-antigen chain length and confers resistance to complement-mediated killing. By contrast, this growth defect did not require the wzzfepE gene, which controls production of very long O-antigen, or other PmrA-activated genes that mediate modifications of lipid A or core regions of the LPS. Additionally, we establish that long O-antigen inhibits growth in bile only in the presence of enterobacterial common antigen, an outer-membrane glycolipid that contributes to bile resistance. Our results suggest that Salmonella regulates the proportion of long O-antigen in its LPS to respond to the different conditions it faces during infection.
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影响因子：
3.5
作者：
CHEREPANOV, PP;WACKERNAGEL, W
通讯作者：
WACKERNAGEL, W
影响因子：
6.7
作者：
Crawford RW;Keestra AM;Winter SE;Xavier MN;Tsolis RM;Tolstikov V;Bäumler AJ
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Bäumler AJ
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de las Mercedes Pescaretti, Maria;Lopez, Fabian E.;Delgado, Monica A.
通讯作者：
Delgado, Monica A.
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3.6
作者：
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通讯作者：
Miller, SI
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3.6
作者：
BASTIN, DA;STEVENSON, G;REEVES, PR
通讯作者：
REEVES, PR