FIGURE 2.

Bacterial trajectories vary in space and time. (A) Two-dimensional trajectories of six typical bacteria (colored and numbered 1–6) and 100 randomly selected bacteria (gray) out of the total experimental population of 7901 bacteria are plotted. Individual trajectories are translated to the origin, and rotated so the bacterium is initially pointed to the right (θ = 0). (B) Angular displacement the same trajectories as a function of time. Positive θ is in the counterclockwise direction, angular velocity is measured in degrees/s. (C) Cumulative path-length as a function of time. Path-length is defined as the sum of the lengths of the line segments connecting individual points in the trajectory and is measured in microns.