FIGURE 2.

Biofilm formation was reduced in PA14 mutant strain ΔntrBC compared to the wild-type (WT). (A) Biofilm formation was significantly reduced in PA14 ΔntrBC compared to the WT. (B) Biofilm formation was similar in PA14 ΔntrBC transformed with plasmid containing ntrBC and WT transformed with plasmid. Briefly, bacteria were seeded from overnight cultures into 96-well microtiter plates at low density (OD₆₀₀ = 0.1) and incubated at 37°C for 24 h statically. Biomass formed in wells was washed and stained with 0.1% crystal violet (CV) prior to dissolution of aggregates with 70% ethanol. Biomass was measured (OD₅₉₅) using a BioTek SynergyH1 microplate reader and taken relative to the WT. Data reported as mean ± standard error of the mean (SEM) from three independent experiments containing three biological replicates each (n = 9). **P < 0.01 according to Welch’s t-test.