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Rapid changes in flagellar rotation induced by external electric pulses
1ERATO (Exploratory Research for Advanced Technology), Molecular Dynamic Assembly Project, Kyoto, Japan.
Biophysical Journal
|December 1, 1991
Summary
Researchers studied the bacterial flagellar motor, a unique biological rotary machine. They found that electric pulses can rapidly alter flagellar rotation speed, demonstrating control over this cellular engine.
Area of Science:
- Microbiology
- Biophysics
- Cellular Mechanics
Background:
- The bacterial flagellar motor is a unique rotary machine.
- It converts proton motive force into mechanical rotational force (torque).
- Understanding its dynamics is key to cellular mechanics.
Purpose of the Study:
- To investigate the dynamic response of bacterial flagellar motors to controlled electrical stimulation.
- To observe how changes in membrane voltage affect flagellar rotation speed.
Main Methods:
- Developed a method to immobilize bacterial cells using a glass micropipette.
- Applied controlled electric pulses via the micropipette to transiently alter membrane voltage.
- Observed and measured the resulting changes in flagellar motor rotation.
Main Results:
- Electric pulses induced rapid acceleration and deceleration of flagellar motor rotation.
- Changes in rotation rate were observed within 5 milliseconds of pulse application.
- Demonstrated a direct, fast correlation between membrane voltage and motor function.
Conclusions:
- Bacterial flagellar motor rotation is dynamically controllable via electrical stimulation.
- The motor exhibits rapid responsiveness to changes in proton motive force.
- This study provides insights into the biophysical control mechanisms of molecular motors.