Quorum sensing and iron regulate a two-for-one siderophore gene cluster in Vibrio harveyi
Quorum sensing and iron regulate a two-for-one siderophore gene cluster in Vibrio harveyi
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DOI：
10.1073/pnas.1805791115
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发表时间：
2018-07-17
影响因子：
11.1
通讯作者：
Morel, Francois M. M.
中科院分区：
文献类型：
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作者：
McRose, Darcy L.;Baars, Oliver;Morel, Francois M. M.
被称为铁载体的铁结合小分子的分泌是微生物在铁限制环境中生存的重要策略。铁载体的产生通常由群体感应（QS）调节，这是一种微生物计数技术，允许生物体根据细胞密度改变基因表达。然而，在QS调控下产生的铁载体的身份和数量很少在它们在铁摄取中的作用的背景下进行研究。我们研究了模型海洋生物哈维弧菌中QS、铁载体和铁摄取之间的联系，其中QS被认为抑制铁载体的产生。我们发现，V. harveyi使用单个q -and - fe抑制基因簇产生细胞相关的铁载体（两亲肠杆菌）以及几种相关的可溶性铁载体，我们使用液相色谱偶联(LC)-质谱以及串联高分辨率质谱（LC- hr -MS/MS）对其进行鉴定和定量。铁载体产生的测量表明，可溶性铁载体的浓度比两栖肠杆菌高100倍，并且在生长过程中，V. harveyi降低了两栖肠杆菌的浓度，但积累了可溶性铁载体。铁-55放射性示踪剂摄取实验表明，这些可溶性铁载体在铁的摄取中起着重要的作用，并且固定相可溶性铁载体的质量控制浓度接近细胞摄取能力的极限。我们提出，细胞相关的和可溶性的铁载体在不同的环境和生长背景下对V. harveyi有益，并且QS允许V. harveyi利用其种群大小的“知识”来避免不必要的铁载体产生。
The secretion of small Fe-binding molecules called siderophores is an important microbial strategy for survival in Fe-limited environments. Siderophore production is often regulated by quorum sensing (QS), a microbial counting technique that allows organisms to alter gene expression based on cell density. However, the identity and quantities of siderophores produced under QS regulation are rarely studied in the context of their roles in Fe uptake. We investigated the link between QS, siderophores, and Fe uptake in the model marine organism Vibrio harveyi where QS is thought to repress siderophore production. We find that V. harveyi uses a single QS-and Fe-repressed gene cluster to produce both cell-associated siderophores (amphiphilic enterobactins) as well as several related soluble siderophores, which we identify and quantify using liquid chromatography-coupled (LC)-MS as well as tandem high-resolution MS (LC-HR-MS/MS). Measurements of siderophore production show that soluble siderophores are present at similar to 100x higher concentrations than amphi-enterobactin and that over the course of growth V. harveyi decreases amphienterobactin concentrations but accumulates soluble siderophores. Fe-55 radio-tracer uptake experiments demonstrate that these soluble siderophores play a significant role in Fe uptake and that the QS-dictated concentrations of soluble siderophores in stationary phase are near the limit of cellular uptake capacities. We propose that cell-associated and soluble siderophores are beneficial to V. harveyi in different environmental and growth contexts and that QS allows V. harveyi to exploit "knowledge" of its population size to avoid unnecessary siderophore production.