FIGURE 4.

Swarming motility was dependent on both ntrB and ntrC. Shown are representative images of mutants and complemented strains. (A) Swarming motility was reduced or completely inhibited in PA14 mutant strains ΔntrB,ΔntrC, and ΔntrBC compared to WT. Swarming motility in PA14 mutant strains transformed with plasmid containing ntrB, ntrC, or ntrBC genes was similar to WT transformed with plasmid. Swarm plates were inoculated with 5 μl of planktonic cells suspended at an OD₆₀₀ = 0.4–0.6 in basal medium (BM2) supplemented with 0.1% casamino acids (CAA) and 0.4% glucose, then incubated for 18–24 h at 37°C. Images captured using a BioRad ChemiDoc. (B) Raw surface area coverage (%) of swarming colonies was assessed using ImageJ software. Data reported as mean ± standard error of the mean (SEM) from three independent experiments containing three biological replicates each (n = 9). *P < 0.05, **P < 0.01 according to Kruskal–Wallis nonparametric test followed by Dunn’s post hoc analysis.