MEASUREMENTS OF MEMBRANE-POTENTIALS IN ESCHERICHIA-COLI-K-12 INNER MEMBRANE-VESICLES WITH THE SAFRANINE METHOD
MEASUREMENTS OF MEMBRANE-POTENTIALS IN ESCHERICHIA-COLI-K-12 INNER MEMBRANE-VESICLES WITH THE SAFRANINE METHOD
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DOI：
10.1016/0005-2736(80)90105-4
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发表时间：
1980-01-01
期刊：
影响因子：
--
通讯作者：
AKERMAN, KEO
中科院分区：
文献类型：
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作者：
HUTTUNEN, MT;AKERMAN, KEO
用带正电荷的染料番红作为探针测定了大肠杆菌的膜电位。大肠杆菌囊泡进行了研究。在用缬氨霉素诱导K+扩散电位过程中或在用从E. coliK-12或ML 308-225进行厌氧生长。缬氨霉素依赖性光谱变化的程度与K+平衡电位的大小线性相关，如从Nernst方程计算的，从50到160 mV（内部负）。甲酸盐诱导的变化也可以通过在缬氨霉素存在下增加K的浓度来校准，形成甲酸盐依赖性反应后。在这种情况下，获得了与用第一种方法获得的结果相同的结果。O2或硝酸盐依赖的甲酸盐氧化导致170 mV的膜电位。抗坏血酸还原的N-甲基吩嗪甲硫酸盐的氧化导致了类似幅度的电位，但在厌氧条件下，硝酸盐只形成了一个小而确定的电位。水溶性醌类化合物杜醌和甲萘醌在甲酸盐或硝酸盐（或O2）存在下，以氧化或还原形式使用时，可产生膜电位。2-羟基-1，4-萘醌不仅无效，而且具有抑制作用。适当浓度的N，N“-二环己基碳二亚胺可增加呼吸或人工诱导的膜电位的形成速率和程度。
The use of safranin, a positively-charged dye, as a probe for the determination of membrane potentials in E. coli vesicles was studied. Shifts in the spectrum of safranine were observed during induction of K+ diffusion potentials with valinomycin or during oxidation of formate by vesicles prepared from cells of E. coli K-12 or ML 308-225 subjected to anaerobic growth with nitrate. The extent of the valinomycin-dependent spectral change correlated linearly with the magnitude of the K+ equilibrium potential, as calculated from the Nernst equation, from 50 to 160 mV (interior negative). The formate-induced changes could also be calibrated by increasing the concentration of K in the presence of valinomycin, after the formation of formate-dependent responses. In this case, results identical to those obtained with the 1st method were obtained. O2 or nitrate-dependent oxidation of formate resulted in a membrane potential of 170 mV. The oxidation of ascorbate-reduced N-methylphenazonium methosulfate resulted in a potential of similar magnitude, but anaerobically with nitrate only a small but definite potential was formed. The water-soluble quinones, duroquinone and menadione, could produce membrane potentials when used in their oxidized or reduced forms in the presence of formate or nitrate (or O2). 2-Hydroxy-1,4-naphthoquinone was not only ineffective but was inhibitory. N,N''-dicyclohexylcarbodiimide at suitable concentrations increased the rate of formation and the extent of membrane potentials induced by respiration or by artificial means.