Fig 7.
The amount of manganese needed to protect Hpx- mutants matches the amount needed to metallate enzymes. AA145 (Hpx- ΔmntH) cells were precultured anaerobically in defined medium (glucose/amino acids) and then subcultured at time zero into aerobic defined medium (glucose/amino acids) containing the indicated concentration of manganese. Optical density was monitored continuously, and MnSOD activity was measured when the cultures reached an OD600 of 0.2. The lowest doubling time, and thus the highest growth rate, for each culture is denoted in the figure.