Fig. 9. Quantification of cell surface area changes during movement under buffer. Aggregation-competent cells, expressing soluble GFP, were filmed by taking confocal stacks at 15-30 second intervals. Changes in relative surface area of representative cells (A) moving randomly; (B) chemotaxing steadily towards a micropipette containing 1-2 µM cAMP; (C) quiescent, but stimulated to move at the start of the sequence with a micropipette containing cAMP; (D) quiescent, but unstimulated.