Movie S2.

Screw-like propagation relies on interaction between the flagellar filament and asperities on the surface. Image sequence selection from Movie S1 during propagation of the cell in screw mode. The white triangle indicates one peak of the flagellar waveform. While the cell moves to the Lower Left, the waveform of the flagellar helix does not move relative to the surrounding medium. Exposure time was 30 ms; playback speed is 1 fps. (Scale bar: 1 µm.) Still images of this movie were used in Fig. 2.