Discovery of a biofilm electrocline using real-time 3D metabolite analysis
Discovery of a biofilm electrocline using real-time 3D metabolite analysis
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DOI：
10.1073/pnas.1117298108
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发表时间：
2011-12-13
影响因子：
11.1
通讯作者：
Whiteley, Marvin
中科院分区：
文献类型：
--
作者：
Koley, Dipankar;Ramsey, Matthew M.;Whiteley, Marvin
细菌是一种社会有机体，具有多种途径来感知和响应其他微生物产生的小分子。自然界中的大多数细菌存在于称为生物膜的固着群落中，生物膜细菌感知和响应邻近生物膜细菌产生的小分子信号和线索的能力尤为重要。为了了解生物膜之间的微生物相互作用，有必要对生物膜周围微环境中的小分子进行快速，实时的空间定量;然而，这种测量一直是难以捉摸的。在这项研究中，扫描电化学显微镜被用来量化3D空间中生物膜周围的小分子。测量由细菌铜绿假单胞菌的生物膜产生的氧化还原活性信号分子绿脓菌素（PYO）的浓度揭示了高浓度的PYO，其在生物膜附近主动维持在还原状态。该梯度导致PYO的还原层，我们将其称为PYO“电跃层”，氧化还原电位的梯度，其从生物膜表面延伸数百微米。我们还表明，PYO电跃层是在电子受体限制条件下形成的，并且有利于形成PYO电跃层的生长条件与可溶性铁的增加相关。此外，我们还拍摄了生物膜表面的“反应图像”，展示了2D表面上细菌氧化还原活性的速率。这些研究建立了微生物产生的小分子的空间协调浓度和氧化还原状态测量方法，并对这些分子在微生物竞争和营养获取中所起的作用提供了令人兴奋的见解。
Bacteria are social organisms that possess multiple pathways for sensing and responding to small molecules produced by other microbes. Most bacteria in nature exist in sessile communities called biofilms, and the ability of biofilm bacteria to sense and respond to small molecule signals and cues produced by neighboring biofilm bacteria is particularly important. To understand microbial interactions between biofilms, it is necessary to perform rapid, real-time spatial quantification of small molecules in microenvironments immediately surrounding biofilms; however, such measurements have been elusive. In this study, scanning electrochemical microscopy was used to quantify small molecules surrounding a biofilm in 3D space. Measuring concentrations of the redox-active signaling molecule pyocyanin (PYO) produced by biofilms of the bacterium Pseudomonas aeruginosa revealed a high concentration of PYO that is actively maintained in the reduced state proximal to the biofilm. This gradient results in a reduced layer of PYO that we have termed the PYO "electrocline," a gradient of redox potential, which extends several hundred microns from the biofilm surface. We also demonstrate that the PYO electrocline is formed under electron acceptor-limiting conditions, and that growth conditions favoring formation of the PYO electrocline correlate to an increase in soluble iron. Additionally, we have taken a " reactive image" of a biofilm surface, demonstrating the rate of bacterial redox activity across a 2D surface. These studies establish methodology for spatially coordinated concentration and redox status measurements of microbe-produced small molecules and provide exciting insights into the roles these molecules play in microbial competition and nutrient acquisition.