Bacteria Motor
The scanning electron micrograph at left shows an overview of the silicon track, designed to coax the bacteria into moving in a uniform direction around the circular tracks. In the center, two cells glide along the wall in the track. The illustration at right of a circular track shows how the bacteria bind to and pull the rotor. Image credit: Yuichi Hiratsuka, et al.

New motor first to be powered by living bacteria
Yuichi Hiratsuka and his colleagues used a species of bacteria called Mycoplasma mobile to power their micromechanical motor. M. mobile, which has micrometer-sized cell body that glides continuously over solid surfaces, can move at speeds of up to 5 micrometers per second. Scientists aren't sure what causes the bacteria to move, other than that several proteins are involved, but Hiratsuka's group was still able to take advantage of the gliding ability by using entire M. mobile cells. The whole cells have been observed to work "more efficiently and intelligently" than nature's smaller motor machines (e.g., proteins and molecules), the scientists reported.
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