MISC

2003年2月

Effect of intracellular pH on rotational speed of bacterial flagellar motors

JOURNAL OF BACTERIOLOGY
  • T Minamino
  • ,
  • Y Imae
  • ,
  • F Oosawa
  • ,
  • Y Kobayashi
  • ,
  • K Oosawa

185
4
開始ページ
1190
終了ページ
1194
記述言語
英語
掲載種別
DOI
10.1128/JB.185.4.1190-1194.2003
出版者・発行元
AMER SOC MICROBIOLOGY

Weak acids such as acetate and benzoate, which partially collapse the transmembrane proton gradient, not only mediate pH taxis but also impair the motility of Escherichia coli and Salmonella at an external pH of 5.5. In this study, we examined in more detail the effect of weak acids on motility at various external pH values. A change of external pH over the range 5.0 to 7.8 hardly affected the swimming speed of E. coli cells in the absence of 34 potassium acetate. In contrast, the cells decreased their swimming speed significantly as external pH was shifted from pH 7.0 to 5.0 in the presence of 34mM acetate. The total proton motive force of. coli cells vas not changed greatly by the presence of acetate. We measured the rotational rate of tethered E. coli cells as a function of external pH. Rotational speed decreased rapidly as the external pH was decreased, and at pH 5.0, the motor stopped completely. When the external pH was returned to 7.0, the motor restarted rotating at almost its original level, indicating that high intracellular proton (H+) concentration sloes nut irreversibly abolish flagellar motor function. Bath the swimming speeds and rotation rates of tethered cells of Salmonella also decreased considerably when the external pH was shifted from pH 7.0 to 5.5 in the presence of 20 mM benzoate. We propose that the increase in the intracellular proton concentration interferes with the release of protons frown the torque-generating units, resulting in slowing or stopping of the motors.

Web of Science ® 被引用回数 : 69

リンク情報
DOI
https://doi.org/10.1128/JB.185.4.1190-1194.2003
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000180966900009&DestApp=WOS_CPL