Fig. 6. mhcA^- cells are unable to move the cell body under the edge of a 2% agarose trough. MhcA^- cells were imaged at the edge of the trough. The dotted line indicates trough edge and the numbers indicate the time in seconds. The vertical white arrow points towards the origin of the chemoattractant gradient and the direction of cell movement. The cells can be seen extending pseudopods under the agarose (arrows), but the cell body remains in the trough so the cells cannot move up the gradient. A QuickTime movie showing the transition event can be viewed at http://jcs.biologists.org/supplemental/.