TABLE 3.

Swarming and surfing motilities of PA14 were reduced in ntrBC mutant strains compared to the wild-type (WT).

Motility	WT	ΔntrB	ΔntrC	ΔntrBC
Swarming	72.24.6%	7.660.33%*	7.490.54%**	1.450.24%**
Swimming	9.871.5%	7.850.94%	9.970.84%	9.241.4%
Twitching	6.510.42%	6.780.55%	6.640.47%	4.890.63%
Surfing	48.31.5%	40.11.8%*	46.02.0%	41.80.55%**

Briefly, swarm and swim plates were inoculated with 5 μl of planktonic cells at an OD₆₀₀ = 0.4–0.6 in basal medium (BM2) supplemented with 0.1% casamino acids or 7 mM (NH₄)₂SO₄ and 0.4% glucose, then incubated for 18–24 h at 37°C. Twitch plates were inoculated with bacteria suspended in Luria broth (LB) and surf plates were inoculated with bacteria suspended in modified sputum-containing cystic fibrosis medium (MSCFM), but otherwise treated similar. Motility of PA14 WT and ntrBC mutants shown as mean surface area coverage ± standard error of the mean from three independent experiments containing three biological replicates each (n = 9). Mutants were significantly reduced for swarming and, more modestly, surfing motilities compared to WT according to a Kruskal–Wallis nonparametric test followed by Dunn’s post hoc analysis (*P < 0.05, **P < 0.01).