Table 1.
Minimum inhibitor concentrations (MICs) for each tested compound alone and fractional inhibitor concentrations (FICs) when tested with N-acetyl cysteine.
Fig 1.
NAC suppresses the expression of Salmonella virulence gene.
hilA and fliC promoters’ activities were determined at varying concentrations of NAC using single-copy transcriptional fusions to the fluorescent proteins GFP and Venus, respectively. Mean total expression of promoters were significantly inhibited at high concentrations of NAC in a dose-dependent manner [NS: not significant, * p-value < 0.05, and ** p-value< 0.001].
Fig 2.
Salmonella develops resistance to NAC.
Both NAC evolved strains and wild type control were grown in either (a) LB medium or (b) M9 medium supplemented with (1.5 mg ml -1). The wild type of control showed inhibited growth as compared to the evolved strains (ES1-3) that tolerate the presence of NAC.
Table 2.
Minimum inhibitor concentrations (MICs) for NAC for wild type versus evolved strains.
MIC results decrease when wild type S. enterica exposed to subinhibitory concentrations of NAC for 30 growth cycles.
Fig 3.
NAC-resistant strains are attenuated.
hilA and fliC promotor activities were measured for the wild type (WT) and NAC evolved strains (ES) growing in LB medium using single-copy transcriptional fusions to GFP and Venus, respectively. The mean total expression of promoter activities in NAC-resistant strains was significantly inhibited (p-value < 0.05) as compared to wild-type control.
Fig 4.
Motility plate assay for NAC-resistant strains versus wild type.
Motility of control strain A: wild type (WT) showed a normal motility zone while NAC evolved strains (ES) B: growing in LB medium or C: M9 medium showed reduced motility.