期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2018
卷号：115
期号：29
页码：7581-7586
DOI：10.1073/pnas.1805791115
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：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 ∼100× higher concentrations than amphi-enterobactin and that over the course of growth V. harveyi decreases amphi-enterobactin concentrations but accumulates soluble siderophores. 55Fe 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.
关键词：siderophores ; quorum sensing ; iron ; Vibrio harveyi ; high-resolution mass spectrometry
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