Fig. 4.

Image of a rotor docked on the track and examples of the rotation of a rotor driven by the bacteria. (A) Scanning electron micrograph of a rotor docked onto a circular groove after placement using a micromanipulator. (Scale bar, 5 μm.) (B) Time-lapse photomicrographs of a rotating rotor taken at 5-s intervals. A portion of the rotor was pseudocolored in cyan to enable tracking. This rotor continuously rotated ≈60 degrees in 5 s (2.0 rpm). (C) Rotational speed of individual rotors. The rotational angles of continuously rotating rotors were measured from images captured at 0.5-s intervals and plotted against time. The traces marked a, b, c, and d correspond to the rotors shown in Movie 1 in sections a, b, and c of Movie 2, respectively.