FIG. 6.

Dose-dependent inhibition of (A) UPEC and (B) S. Typhimurium motility by compound 1. Dose-response plots of relative motility for (A) UPEC CFT073 2KO transiently expressing DsbAB (closed circles) or DsbLI (open squares) and (B) S. Typhimurium SL1344 3KO complemented with EcDsbA (closed circles), SeDsbA (open squares), SeDsbLI (closed squares), or SeSrgA (open circles). Relative% motility was calculated by measuring the diameter of the motility zone for each strain in media containing 0.005, 0.05, 0.1, 1, or 3 mM of inhibitor F1 and dividing by the diameter of the same strain swimming in DMSO-containing media (carrier control). Dot plots represent mean relative motility ± SEM of four independent replicates. (C) Inhibition of S. Typhimurium DsbL by EcDsbA inhibitors. Intensity of fluorescent colonies of S. Typhimurium SL1344 3KO complemented with SeDsbLI. SeDsbLI catalyzes disulfide formation in arysulfate sulfotransferase, which can cleave MUS to release a fluorescent product. Bacteria were cultured in lysogeny broth-MUS agar plates with or without inhibitors (1 mM) and imaged in a BioRad GelDoc. The colony intensity of 30 colonies per plate was measured as adjusted volume (background-adjusted sum of all intensities within the colony boundaries) in Image Lab 5.0 and is shown as dot plots with group means and 95% confidence intervals. Addition of F1, F2, F3, or F4 in the agar resulted in a significant reduction in mean colony intensity compared with DMSO-containing plates, *p < 0.05, ANOVA. MUS, methylumbelliferyl sulfate; SeDsbA, DsbA from S. enterica serovar Typhimurium.