Base and acid resistance of B. subtilis associated with transcriptomic responses. Bacillus subtilis

Gene expression profiles of Bacillus subtilis strain AG174 were compared as a function of steady-state external pH during growth with aeration. Aerated overnight cultures were diluted 1:500 and incubated in 250 mL baffled flasks containing potassium-modified Luria-Bertani medium (LBK) buffered with 50 mM HOMOPIPES at pH 6.0, pH 7.0, and pH 9.0. Tubes were incubated at 37°C with aeration (260 rpm) to an optical density at 600 nm of 0.2. For each of the three pH conditions, RNA was isolated from five independent cultures. Overall design: Overnight cultures were diluted 1:500 and incubated in 250 mL baffled flasks containing potassium-modified Luria-Bertani medium (LBK) buffered with 50 mM HOMOPIPES at pH 6.0, pH 7.0, and pH 9.0. Cultures were incubated at 37°C with aeration (260 rpm) to an optical density at 600 nm of 0.2. Five replicate cultures were grown at each pH.