FIG. 1.

Phenotypic characterization of wild-type and mutant M. xanthus strains, performed as described in Materials and Methods. Wild-type DZ2 forms fruiting bodies on CF agar after 2 days of incubation (a); SW301 does not form any fruiting bodies even after 5 days (b). On CYE plus 0.3% agar, DZ2 forms a swarming colony about 4.0 cm in diameter after 5 days (c); the colony formed by SW301 is 1.5 cm in diameter (d). On 1.5% agar, advancing colony edges of DZ2 contain both single cells and large cell groups (e), while those of SW301 contain only single cells and small cell groups (f). SW300 shows the same phenotype as SW301.