Wheel of Life: Bacteria provide horsepower for tiny motor

For millennia, people have hitched beasts to plows to exploit the animals’ strength and energy. In a modern variant of that practice, scientists have chemically harnessed bacteria to a micromotor so that they can make the device’s rotor slowly turn.

PULLING MY LEGS. When bacteria crawl clockwise in the circular groove underlying this motor, they brush past the tabs that support the motor’s star-shaped rotor.