FIG 5.

Bactericidal effect of simultaneous addition of cholic acid and PS900. (A) Overnight WT, HT014, and HT015 cultures were serially diluted (10-fold) and then spotted onto BHI agar plates together with 0.1% DMSO (control), 10 μM MH44, or 10 μM PS900 without cholic acid (CA). Growth was visualized after 48 h of incubation at 37°C. (B) Overnight WT, HT014, and HT015 cultures were serially diluted (10-fold) and then spotted onto BHI agar plates together with 0.1% DMSO (control), 10 μM MH44, or 10 μM PS900 with 10 mM cholic acid (CA). Growth was visualized after 48 h of incubation at 37°C. (C) Relative fluorescence of PS900 dissociation from L. monocytogenes WT, HT014, and HT015. Overnight WT, HT014, and HT015 cultures (5 OD unit) were washed and precultivated in BHI medium with/without 10 mM CA for an hour at 37°C. These cultures were treated with 10 μM PS900 for 15 min, washed, and further incubated in PBS for 30 min at 37°C. The fluorescence signals emitted from PS900 (λ_ex = 400 nm and λ_em = 440 nm) were normalized to the OD₆₀₀ measurements. The dissociation results were plotted as the percentages of PS900 fluorescence (relative to the initial fluorescence, 100% at t = 0) over a 30-min time course. All measurements were performed in triplicates, and the results were plotted using GraphPad Prism (version 9.3.1). Error bars represent standard deviations of replicates.