Differential Requirement for PBP1a and PBP1b in In Vivo and In Vitro Fitness of Vibrio cholerae
Differential Requirement for PBP1a and PBP1b in In Vivo and In Vitro Fitness of Vibrio cholerae
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DOI：
10.1128/iai.00012-14
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发表时间：
2014-05-01
影响因子：
3.1
通讯作者：
Waldor, Matthew K.
中科院分区：
文献类型：
--
作者：
Doerr, Tobias;Moell, Andrea;Waldor, Matthew K.
我们研究了霍乱弧菌高分子量双功能青霉素结合蛋白PBP 1a和PBP 1b在这种肠道病原体的适应性中的作用。使用合成致死性的筛选，我们发现霍乱弧菌PBP 1a和PBP 1b蛋白，像它们的大肠杆菌同源物一样，在不存在另一种和不存在另一种假定的激活剂（外膜脂蛋白LpoA和LpoB）的情况下，分别是必不可少的。对霍乱弧菌突变体的比较分析表明，霍乱弧菌的PBP 1a/LpoA在产生和/或维持病原体的细胞壁方面比PBP 1b/LpoB发挥更突出的作用。在所有测试条件下，缺乏PBP 1b或LpoB的霍乱弧菌都表现出野生型生长。相比之下，缺乏PBP 1a或LpoA的霍乱弧菌在脱氧胆酸盐和胆汁存在下的基本培养基中以及在体外和幼鼠小肠中与野生型细胞的竞争试验中表现出生长缺陷。PBP 1a途径突变体在稳定期特别受损，这使得它们对来自稳定期野生型细胞的上清液中存在的产物敏感。当指数期细胞而不是静止期细胞用于哺乳小鼠时，体内PBP 1a途径突变体的显著竞争缺陷基本上不存在。因此，至少对于霍乱弧菌PBP 1a途径突变体，接种物的生长期是感染性的关键调节剂。
We investigated the roles of the Vibrio cholerae high-molecular-weight bifunctional penicillin binding proteins, PBP1a and PBP1b, in the fitness of this enteric pathogen. Using a screen for synthetic lethality, we found that the V. cholerae PBP1a and PBP1b proteins, like their Escherichia coli homologues, are each essential in the absence of the other and in the absence of the other's putative activator, the outer membrane lipoproteins LpoA and LpoB, respectively. Comparative analyses of V. cholerae mutants suggest that PBP1a/LpoA of V. cholerae play a more prominent role in generating and/or maintaining the pathogen's cell wall than PBP1b/LpoB.V. cholerae lacking PBP1b or LpoB exhibited wild-type growth under all conditions tested. In contrast, V. cholerae lacking PBP1a or LpoA exhibited growth deficiencies in minimal medium, in the presence of deoxycholate and bile, and in competition assays with wild-type cells both in vitro and in the infant mouse small intestine. PBP1a pathway mutants are particularly impaired in stationary phase, which renders them sensitive to a product(s) present in supernatants from stationary-phase wild-type cells. The marked competitive defect of the PBP1a pathway mutants in vivo was largely absent when exponential-phase cells rather than stationary-phase cells were used to inoculate suckling mice. Thus, at least for V. cholerae PBP1a pathway mutants, the growth phase of the inoculum is a key modulator of infectivity.