Fig. 2.

Growth of wild-type L. monocytogenes EGD (filled circle), ΔaxyR mutant (filled diagonal), ΔphoP mutant (filled square) and Δfri mutant (filled triangle) in BHI broth pH 5 adjusted with HCl (a) and in BHI broth supplemented with 0.5 M KCl (b). Overnight cultures were inoculated (1:100) into BHI broth supplemented with appropriate stressor, and cultures were incubated with shaking at 37 °C. Cell growth was measured spectrophotometrically by determining the optical density at 600 nm. Error bars, standard deviations from three independent experiments