Fig. 3

Effects of 12 h exposure to decreasing concentration of tylosin (initial concentration of 3 μg/mL) on the gene expression of S. Typhimurium efflux pump: acrA (a) acrB (b) tolC (c), and genes encoding their global regulators marA (d) soxS (e) ramA (f). The gene expression value for the non-exposed S. Typhimurium is 1. The gene expression of outer membrane proteins: ompC (a) and ompF (a) are displayed in Fig. g and h, respectively. Bar graphs indicate the mean ± SD of three independent experiments. *P < 0.05; ** P < 0.01; *** P < 0.001 compared to the non-exposed S. Typhimurium