Fig 4.

Menadione growth inhibition assays. Wild-type DC3000, the single (A), double (B), and triple (C) catalase mutants, and their Tn7 complemented strains were assessed for their sensitivity to menadione toxicity. The bacteria were resuspended to 1 × 10⁸ cells ml⁻¹, and 10 μl of 10-fold serial dilutions was spotted on KB plates with or without 0.2 mM menadione (MD). Pictures were taken 48 h later. The pictures are representative of three independent experiments.