Chemotaxis of Spirochaeta aurantia: involvement of membrane potential in chemosensory signal transduction
Chemotaxis of Spirochaeta aurantia: involvement of membrane potential in chemosensory signal transduction
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橙色螺旋毛菌的趋化性：膜电位参与化学感应信号转导
DOI：
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发表时间：
1981
影响因子：
3.2
通讯作者：
E. Greenberg
中科院分区：
文献类型：
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作者：
E. Goulbourne;E. Greenberg
以荧光阳离子3，3‘-二丙基-2，2’-硫代二碳菁碘为探针，采用定量毛细管电泳法研究了呋喃霉素和黑素对橙色螺旋藻糖类趋化作用的影响。在钾或钠磷酸盐缓冲液中加入化学诱导剂D-木糖，可引起瞬时的膜去极化。在磷酸二氢钾缓冲液中加入呋喃霉素后，细胞膜电位降低，D-木糖引起的瞬时膜去极化现象被消除。虽然没有检测到呋喃霉素对细胞运动的影响，但在磷酸二氢钾缓冲液中细胞的D-木糖趋化可被呋喃霉素完全抑制。在磷酸二氢钠缓冲液中，呋喃霉素对膜电位和D-木糖趋向性的影响不大。众所周知，在磷酸二氢钾缓冲液中，尼格列星能消除橙色葡萄球菌的跨膜pH梯度。这种化合物不会消散细胞在钾或磷酸钠缓冲液中加入D-木糖时观察到的膜电位或瞬时膜去极化。尼格列星不抑制D-木糖在磷酸盐缓冲液中的趋化作用。本研究表明，在化学传感信号转导过程中，可能与膜电位有关，而与跨膜pH梯度无关。
The effects of valinomycin and nigericin on sugar chemotaxis in Spirochaeta aurantia were investigated by using a quantitative capillary assay, and the fluorescent cation, 3,3'-dipropyl-2,2'-thiodicarbocyanine iodide was used as a probe to study effects of chemoattractants on membrane potential. Addition of a chemoattractant, D-xylose, to cells in either potassium or sodium phosphate buffer resulted in a transient membrane depolarization. In the presence of valinomycin, the membrane potential of cells in potassium phosphate buffer was reduced, and the transient membrane depolarization that resulted from the addition of D-xylose was eliminated. Although there was no detectable effect of valinomycin on motility, D-xylose taxis of cells in potassium phosphate buffer was completely inhibited by valinomycin. In sodium phosphate buffer, valinomycin had little effect on membrane potential or D-xylose taxis. Nigericin is known to dissipate the transmembrane pH gradient of S. aurantia in potassium phosphate buffer. This compound did not dissipate the membrane potential or the transient membrane depolarization observed upon addition of D-xylose to cells in either potassium or sodium phosphate buffer. Nigericin did not inhibit D-xylose taxis in either potassium or sodium phosphate buffer. This study indicates that the membrane potential but not the transmembrane pH gradient of S. aurantia is somehow involved in chemosensory signal transduction.