(a) Zymography of catalase activities during various stages. B. pseudomallei PP844 wild type (WT), the rpoN2 isogenic mutant (rpoN2 mutant), and the rpoN2 mutant carrying the rpoN2-complementing plasmid (rpoN2 complement) were grown aerobically in LB medium for 12, 24, 48, and 72 hours. The extracted cells (15 μg of protein) were prepared for electrophoresis in 10% nondenaturing polyacrylamide gel and stained for catalase activity in a solution of 2% (w/v) ferric chloride-potassium ferric cyanide. (b) Relative quantification real-time RT-PCR (qRT-PCR) for B. pseudomallei katE expression was compared between the rpoN2 isogenic mutant (N2 mutant) and the wild type PP844 (WT) at various stages (24, 48, and 72 hours) of growth. The katE gene primers were designed using Primer3 software. All fold difference values were normalized with 23s rRNA expression and the values are the mean standard deviations; analysis is performed in triplicate.