FIG. 3.
Visualization of catalase activity on a native polyacrylamide gel. Cell-free protein extracts were isolated from B. cereus ATCC 14579 (WT) and B. cereus FM1400 (−sigB) cells in the mid-exponential growth phase in BHI (me) and after a 30-min exposure to 42°C (hs). Proteins (100 μg) were separated on a nondenaturing 10% polyacrylamide gel and stained for catalases as described by Woodbury et al. (27), resulting in light catalase bands against a dark background. The large arrow points to the main vegetative-cell catalase. The small arrow points to the σB-dependent catalase KatE.