Fig 1. Characterization of M. xanthus ΔpilR suppressor mutants.

(A) Representative suppressor mutations were observed after prolong incubation (7–14 days) on 0.5% agar. (B) Nine suppressor mutants were characterized for T4P-dependent motility related-phenotypes including motility rate (mm/day), sedimentation in static cultures reported as the percentage of lost absorbance at OD₆₀₀ after 2 hours, and extracellular polysaccharide (EPS) production measured by the binding of Trypan blue to whole cells in solution and normalized to wild-type DZ2 which was set at 100%. All data represent the averages of at least 3 biological replicates. All suppressor mutant (C1-C9) measurements were significantly different (t-test, p<0.05) from wild-type DZ2 and ΔpilR with the exception of the EPS production of C6, C8, and C9 which were not different from that of the wild-type DZ2. Western blot analysis of total PilA from whole cell lysates was normalized to total protein determined by Bradford assay. All lysates were on the same blot, developed together, and can be directly compared to each other.