Fig 6.
Comparison of acid resistance provided by native and rhamnose-regulated arginine decarboxylase. S. flexneri 2457T, Ty2, χ11500 (ΔadiA-adiC), χ11548 (ΔaroD), and χ11568 (ΔaroD PrhaBAD adiAC) were grown overnight in TSB medium with 0.4% glucose and 0.1% rhamnose under anaerobic conditions. Cells were challenged for 4 h with EG medium containing 1 mM arginine at pH 3.0 (A) or pH 2.5 (B). Survival in all assays was monitored by plating on LB agar containing all necessary supplements. The data shown are the means and SEM from three independent assays.