FIGURE 4.

Determination of the oxidative stress state of C. crescentus NA1000 in response to iron levels. Wild type NA1000 strain cultures were grown in M2 (A,B), DP-treated M2 (DP for 2 h) (C,D), or iron-limited M2 for 4 h (E,F); and cultures of the fur mutant were grown in M2 (G,H) or DP-treated M2 for 2 h (I,J). As a control, NA1000 cultures received H₂O₂ for 5 mM and incubated for 15 min (K,L). Samples were treated with dihydrorhodamine 123 and analyzed by fluorescence microscopy using a fluorescein filter (A,C,E,G,I,K) and under light microscopy (B,D,F,H,J,L).