Fluorescence measurement of intracellular sodium concentration in single Escherichia coli cells.
Fluorescence measurement of intracellular sodium concentration in single Escherichia coli cells.
复制标题
单个大肠杆菌细胞内钠浓度的荧光测量。
DOI：
10.1529/biophysj.105.071332
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发表时间：
2006
影响因子：
3.4
通讯作者：
R. Berry
中科院分区：
文献类型：
--
作者：
Chien;M. Leake;R. Berry
细菌的能量转导细胞质膜包含维持膜电位和离子梯度的泵和反向端口。我们开发了一种使用钠离子荧光指示剂钠绿快速单细胞测量大肠杆菌内部钠浓度 ([Na(+)](in)) 的方法。细菌鞭毛马达是一种分子机器，它将质子 (H(+)) 或钠离子 (Na(+)) 等离子的跨膜流与鞭毛旋转耦合起来。我们使用了含有嵌合鞭毛马达的大肠杆菌菌株，该鞭毛马达具有 H(+) 和 Na(+) 驱动组件，可充当钠马达。在 1-85 mM 范围内改变外部钠浓度 ([Na(+)](ex)) 会导致 [Na(+)](in) 在 5-14 mM 之间变化，表明内部钠浓度部分稳态。 [Na(+)](in)和[Na(+)](ex)之间的关系存在显着的细胞间差异，并且不表达嵌合鞭毛马达的细胞中的内部钠浓度低2-3倍，表明通过这些马达的钠通量是进入细胞的总钠通量的重要部分。
The energy-transducing cytoplasmic membrane of bacteria contains pumps and antiports maintaining the membrane potential and ion gradients. We have developed a method for rapid, single-cell measurement of the internal sodium concentration ([Na(+)](in)) in Escherichia coli using the sodium ion fluorescence indicator, Sodium Green. The bacterial flagellar motor is a molecular machine that couples the transmembrane flow of ions, either protons (H(+)) or sodium ions (Na(+)), to flagellar rotation. We used an E. coli strain containing a chimeric flagellar motor with H(+)- and Na(+)-driven components that functions as a sodium motor. Changing external sodium concentration ([Na(+)](ex)) in the range 1-85 mM resulted in changes in [Na(+)](in) between 5-14 mM, indicating a partial homeostasis of internal sodium concentration. There were significant intercell variations in the relationship between [Na(+)](in) and [Na(+)](ex), and the internal sodium concentration in cells not expressing chimeric flagellar motors was 2-3 times lower, indicating that the sodium flux through these motors is a significant fraction of the total sodium flux into the cell.