Document Detail

Microscopic analysis of bacterial motility at high pressure.
MedLine Citation:
PMID:  22768943     Owner:  NLM     Status:  MEDLINE    
The bacterial flagellar motor is a molecular machine that converts an ion flux to the rotation of a helical flagellar filament. Counterclockwise rotation of the filaments allows them to join in a bundle and propel the cell forward. Loss of motility can be caused by environmental factors such as temperature, pH, and solvation. Hydrostatic pressure is also a physical inhibitor of bacterial motility, but the detailed mechanism of this inhibition is still unknown. Here, we developed a high-pressure microscope that enables us to acquire high-resolution microscopic images, regardless of applied pressures. We also characterized the pressure dependence of the motility of swimming Escherichia coli cells and the rotation of single flagellar motors. The fraction and speed of swimming cells decreased with increased pressure. At 80 MPa, all cells stopped swimming and simply diffused in solution. After the release of pressure, most cells immediately recovered their initial motility. Direct observation of the motility of single flagellar motors revealed that at 80 MPa, the motors generate torque that should be sufficient to join rotating filaments in a bundle. The discrepancy in the behavior of free swimming cells and individual motors could be due to the applied pressure inhibiting the formation of rotating filament bundles that can propel the cell body in an aqueous environment.
Masayoshi Nishiyama; Yoshiyuki Sowa
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biophysical journal     Volume:  102     ISSN:  1542-0086     ISO Abbreviation:  Biophys. J.     Publication Date:  2012 Apr 
Date Detail:
Created Date:  2012-07-09     Completed Date:  2012-10-09     Revised Date:  2013-07-12    
Medline Journal Info:
Nlm Unique ID:  0370626     Medline TA:  Biophys J     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1872-80     Citation Subset:  IM    
Copyright Information:
Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.
PRESTO, Japan Science and Technology Agency, Saitama, Japan.
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MeSH Terms
Escherichia coli / cytology*,  metabolism
Flagella / metabolism

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