FIG. 6.

Effects of the iron chelator DTPA on the aerobic growth of E. coli wild-type and iron-storage mutants. Details are as for Fig. 5A except where stated. (A) Effects of DTPA (5 μM). (B) Reversal of the effects of 5 μM DTPA by iron citrate. W3110 is indicated by solid symbols, and JRG2953 (ftnA bfr) is indicated by open symbols, with iron citrate concentrations as follows: ◊ and ⧫, 0.5 μM; ▵ and ▴, 1.5 μM; □ and ■, 5 μM; and ○ and ●, 16 μM. (C) Effect of low-iron preculture on subsequent growth in 5 μM DTPA: precultures were grown with 1.6 mM sodium citrate instead of 16 μM iron citrate, as in Fig. 5B. (D) Comparison of log-phase (open symbols) and stationary-phase (solid symbols) preculture on subsequent growth in 5 μM DTPA: ▴ and ▵, W3110; ■ and □, JRG2953 (ftnA bfr).