Real-Time Metabolic Interactions between Two Bacterial Species Using a Carbon-Based pH Microsensor as a Scanning Electrochemical Microscopy Probe.
Real-Time Metabolic Interactions between Two Bacterial Species Using a Carbon-Based pH Microsensor as a Scanning Electrochemical Microscopy Probe.
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DOI：
10.1021/acs.analchem.7b03050
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发表时间：
2017-10-17
影响因子：
7.4
通讯作者：
Koley D
中科院分区：
文献类型：
--
作者：
Joshi VS;Sheet PS;Cullin N;Kreth J;Koley D
我们开发了一种基于碳的快速响应电位 pH 微传感器，用作扫描电化学显微镜 (SECM) 化学探针，以定量绘制两种细菌物种（共生链球菌和致病性变形链球菌）之间的微生物代谢交换。直径 25 μm 的 H+ 离子选择性微电极或 pH 微探针显示出 59 mV/pH 的能斯特斜率，并对 Na+、K+、Ca2+ 和 Mg2+ 等主要离子具有高选择性。此外，独特的导电膜成分帮助我们执行电流分析曲线来定位探针，并获得由产生乳酸的变形链球菌生物膜产生的微环境的高分辨率 pH 图。对 S. mutans 的 x 向 pH 扫描还显示了 pH 曲线对另一个物种（产 H2O2 的 S. gordonii）代谢活动的影响。当这些细菌物种在空间上非常接近时，我们观察到戈氏链球菌上方局部 H2O2 浓度最初增加约 12±5 μM，随后随着乳酸的产生，H2O2 浓度逐渐下降（>30 分钟）至几乎为零，随后 pH 值下降，变形链球菌的代谢输出更加明显。这些结果得到了基因表达和共焦荧光显微镜研究的支持。我们的研究结果表明，产生 H2O2 的戈氏链球菌占主导地位，而唾液的缓冲能力有效（~pH 6.0），但逐渐被变形链球菌取代，因为后者通过产生乳酸慢慢开始将局部 pH 值降低至 5.0 或更低。我们的观察证明了我们的 SECM 化学探针在研究两种细菌物种之间的实时代谢相互作用方面具有独特的能力，而这在传统测定中是无法实现的。
We have developed a carbon-based, fast-response potentiometric pH microsensor for use as a scanning electrochemical microscopy (SECM) chemical probe to quantitatively map the microbial metabolic exchange between two bacterial species, commensal Streptococcus gordonii and pathogenic Streptococcus mutans. The 25-μm diameter H+ ion-selective microelectrode or pH microprobe showed a Nernstian slope of 59 mV/pH and high selectivity against major ions such Na+, K+, Ca2+ and Mg2+. In addition, the unique conductive membrane composition aided us in performing an amperometric approach curve to position the probe and obtain a high-resolution pH map of the microenvironment produced by the lactate-producing S. mutans biofilm. The x-directional pH scan over S. mutans also showed the influence of the pH profile on the metabolic activity of another species, H2O2-producing S. gordonii. When these bacterial species were placed in close spatial proximity, we observed an initial increase in the local H2O2 concentration of approximately 12±5 μM above S. gordonii, followed by a gradual decrease in H2O2 concentration (>30 min) to almost zero as lactate was produced, and a subsequent decrease in pH with a more pronounced metabolic output of S. mutans. These results were supported by gene expression and confocal fluorescence microscopic studies. Our findings illustrate that H2O2-producing S. gordonii is dominant while the buffering capacity of saliva is valid (~pH 6.0) but is gradually taken over by S. mutans as the latter species slowly starts decreasing the local pH to 5.0 or less by producing lactic acid. Our observations demonstrate the unique capability of our SECM chemical probes for studying real-time metabolic interactions between two bacterial species, which would not otherwise be achievable in traditional assays.
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影响因子：
15.9
作者：
Hajishengallis G;Lamont RJ
通讯作者：
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影响因子：
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作者：
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影响因子：
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作者：
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DOI：
10.1073/pnas.1117298108
发表时间：
2011-12-13
影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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