Rapid rotation of flagellar bundles in swimming bacteria

@article{Lowe1987RapidRO,
  title={Rapid rotation of flagellar bundles in swimming bacteria},
  author={Graeme Lowe and Markus Meister and Howard C. Berg},
  journal={Nature},
  year={1987},
  volume={325},
  pages={637-640}
}
A bacterial flagellum is driven by a reversible rotary motor1–3. The power input is determined by protonmotive force and proton flux, the power output by torque and speed: interrelationships between these parameters provide important clues to motor mechanisms. Here we describe the relationship between torque and speed at constant protonmotive force. The measurements are analogous to those that could be made by plugging an electric motor into a constant-voltage outlet, varying the external load… 
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TLDR
Bacteria swim by rotating long thin helical filaments, each driven at its base by a reversible rotary motor, and motor reversals were necessary, although not always sufficient, to cause changes in filament chirality.
Torque-speed relationship of the Na+-driven flagellar motor of Vibrio alginolyticus.
The bacterial flagellar motor.
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