Fig. 5. Development of starved Ax-2 cells and cells on agar. Ax-2 cells and cells were washed twice in BSS and plated on 1.5% non-nutrient agar at a density of 5x10⁶ cells/cm². This was followed by incubation for the indicated times at 22°C. (A) Nontreated Ax-2 cells formed aggregation streams after 6 hours and mounds after 12 hours of incubation. Subsequently a tip was formed at the apex of each mound, elongated and constructed a migrating slug after 16 hours of incubation. This was followed by formation of a fruiting body at about 26 hours of incubation. By contrast, cells exhibited delayed and somewhat abnormal morphogenesis; large aggregation streams were formed after 16 hours of incubation, followed by their subdivision to smaller cell masses (A). (B) Gross morphology of final structures: fruiting bodies derived from nontreated cells and irregular-shaped slugs derived from cells. The cells stopped their development at the slug stage and never formed fruiting bodies. Bars, 1 mm.