Click on image to view larger version.

Fig. 6. Mutant S13A cells respond to a sequence of simulated temporal waves of cAMP
generated in the absence of spatial gradients by increasing and decreasing
velocity in a manner similar to wild-type JH10 cells. The instantaneous
velocity is plotted as a function of time for a representative JH10 cell (A)
and a representative S13A-1 cell (B) during four simulated waves. The
estimated cAMP concentration, measured in dye experiments
(Wessels et al., 2000b), is
presented as a function of time through the four waves. Note that the velocity
of neither JH10 nor S13A-1 cells increases in the front of the first simulated
wave, a result previously reported for wild-type cells
(Varnum et al., 1985).
Instantaneous velocity was measured at 5 second intervals. Instantaneous
velocity plots were smoothed 10 times with Tukey windows of 10, 20, 40, 20 and
10. Results similar to those for the representative JH10 and S13A-1 cells were
obtained for nine additional cells of each respective cell line. Results
similar to those for S13A-1 cells were obtained with S13A-2 cells.