FIG. 2.

Representative tracks shown within a 42-μm by 57-μm frame. The beginning of each track is indicated by a black dot. The traces of the head, center, and tail (defined at the beginning of the track) are plotted in blue, red, and green, respectively, and the axis of the cell body is shown in magenta (dotted). Frame numbers are indicated at the leading end of the cell. (A) A cell that moved forward for the first 35 frames and then was pushed sideways (exhibited lateral translational movement) for the last 10 frames. (B) A cell that moved forward for the first 13 frames, reversed during the next 8 frames, and finally was pushed sideways (exhibited lateral translational movement) for the last 13 frames. Note that at the end of this track, the blue line lags behind the green line. (C) A cell that moved forward for the first 8 frames, was pushed sideways (exhibited lateral rotational movement) for the next 8 frames, and then continued forward. (D) A cell with two deflections due to motor reversals. The cell moved forward during the first 17 frames (increasing its propulsion angle at frame 10), reoriented its cell body during the next 7 frames in response to the first motor reversal, moved forward for another 10 frames, and then moved laterally during the last 3 frames in response to a second motor reversal. At this point, the cell left the field of view. The frames are 1/30 s apart.