FIG 6.

Sucrose enhances the ability of YqjA to provide alkaline tolerance in the presence of a suboptimal concentration of sodium. (A) ΔyqjA harboring pBADyqjA was grown to mid-log phase at pH 7.0 and then inoculated into salt-free liquid LB-Amp medium at pH 9.25 containing 0 mM sucrose, 0 mM NaCl, 300 mM sucrose and 0 mM NaCl, 0 mM sucrose and 50 mM NaCl, 300 mM sucrose and 50 mM NaCl, or 0 mM sucrose and 100 mM NaCl, and growth was monitored. (B) ΔyqjA harboring the control vector pBAD or pBADyqjA was grown to mid-log phase at pH 7.0, and then 5 μl of serially diluted cells was spotted onto LB-Amp medium plates at pH 9.25 containing 0 mM NaCl, 50 mM NaCl, 100 mM sucrose, 50 mM NaCl plus 100 mM sucrose, or 100 mM NaCl. The plates were incubated at 37°C for 20 to 24 h. The error bars indicate standard deviations of three independent measurements.