Related Experiment Videos
The Rhodobacter sphaeroides flagellar motor is a variable-speed rotor
H L Packer1, H Lawther, J P Armitage
1Department of Biochemistry, University of Oxford, UK.
FEBS Letters
|June 2, 1997
Summary
The Rhodobacter sphaeroides motor exhibits variable rotation rates and complex stopping dynamics, unlike the consistent motor of Escherichia coli. Chemokinetic stimulation enhances its torque and stabilizes rotation.
Area of Science:
- Microbiology
- Bacterial Motility
- Biophysics
Background:
- Bacterial flagellar motors are crucial for motility and chemotaxis.
- Unidirectional motors, like that in Rhodobacter sphaeroides, exhibit unique dynamics.
- Understanding motor function is key to deciphering bacterial navigation strategies.
Purpose of the Study:
- To investigate the rotation rate and stopping dynamics of the Rhodobacter sphaeroides flagellar motor.
- To compare the motor's behavior with that of Escherichia coli.
- To analyze the effects of chemokinetic stimulation on motor performance.
Main Methods:
- Computerized motion analysis of tethered Rhodobacter sphaeroides cells.
- High-speed video capture for precise temporal analysis (frame rate: 0.02 s).
- Comparison with wild-type and CheR mutant Escherichia coli.
Main Results:
- Rhodobacter sphaeroides motor shows variable rotation rates, contrasting with Escherichia coli's consistent speed.
- Stopping and restarting dynamics are complex, ranging from instantaneous to gradual (0.02 s to 0.25 s).
- Chemokinetic stimulation increased torque generation and reduced rotation rate variability.
Conclusions:
- The Rhodobacter sphaeroides motor possesses more complex and variable dynamics than previously characterized.
- Rapid and variable stopping/restarting mechanisms are key features of this motor.
- Chemotaxis likely involves modulation of motor torque and rotation stability.