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Updated: Jun 29, 2026
06:08
Biophysical Characterization of Flagellar Motor Functions
Published on: January 18, 2017
Bacterial flagella are firmly anchored
Nicholas C Darnton1, Howard C Berg
1Rowland Institute at Harvard, Cambridge, Massachusetts 02142, USA.
Journal of Bacteriology
|October 14, 2008
Summary
Salmonella mutants shed flagella, but optical traps couldn't detach them. This indicates that bacterial flagella, even when partially detached, remain firmly anchored to the cell.
Area of Science:
- Microbiology
- Bacterial Motility
- Molecular Biology
Background:
- Salmonella enterica utilizes flagella for motility.
- Specific mutants (fliF, fliL) exhibit flagellar shedding under certain conditions.
- Understanding flagellar anchoring is crucial for bacterial adhesion and pathogenesis.
Purpose of the Study:
- To investigate the mechanical properties of flagellar anchoring in Salmonella mutants.
- To determine if flagella can be fully detached from the cell using external forces.
Main Methods:
- Utilized Salmonella enterica mutants with fliF and fliL gene disruptions.
- Induced flagellar shedding in viscous media and on soft agar surfaces.
- Employed optical trapping to apply force and attempt flagellar filament extraction.
Main Results:
- Mutants successfully shed flagellar filaments, including hooks and distal rod segments (FlgG).
- Optical trapping failed to extract flagellar filaments, even with forces sufficient to straighten them.
- Demonstrated strong, persistent anchoring of flagella to the bacterial cell.
Conclusions:
- Flagellar filaments are robustly anchored to Salmonella cells, resisting significant mechanical stress.
- The shedding phenotype in these mutants does not imply complete detachment from the basal body or cell envelope.
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