Fig. 6. Development of starved Ax-2 cells and cells under submerged conditions. Ax-2 cells and cells were washed twice in BSS and plated in a 24-well plate (1 ml cell suspension/well) at 5x10⁵ cells/cm². This was followed by incubation for the indicated times at 22°C. Almost all the cells showed no sign of cell aggregation and remained as round-shaped single cells even after 12 hours of incubation, while nontreated Ax-2 cells acquired aggregation-competence and began to aggregate at 7 hours of incubation, followed by formation of tight mounds during 12-24 hours of incubation. By contrast, cells formed large aggregation streams at 24 hours, which were then subdivided into smaller mounds during another 4 hours of incubation. Bars, 200 µm.