Fig. 3.

Impact of leuO on lysine decarboxylase production in V. cholerae. The WT strain JB58, ΔleuO strain XBV222, ΔaphB strain XBV148 and ΔleuO strain carrying the pBAD18Km-leuO plasmid pXB298 were grown in AKI media under AKI conditions at 37 °C for 4 h when lysine decarboxylase activity was quantified as described in Methods. Strains containing the arabinose inducible pBAD18Km-leuO were grown in the presence or absence of 0.02 % arabinose. Lysine-decarboxylase-specific activity was defined as the amount of lysine converted to cadaverine per minute divided by the optical density at 600 nm. The presented data are the mean ± sd of three independent experiments. *P = 0.16; **P>0.05.