FIG. 2.

Uptake of ⁵⁵FeCl₃ by Y. pestis strains KIM6+ (Ybt⁺ TonB⁺), KIM6-2073+ (Ybt⁺ TonB⁻), and KIM6-2045.1 (Psn⁻ TonB⁺) was monitored as described previously (1, 6). Where indicated (closed symbols), cells were metabolically poisoned by addition of 100 μM carbonyl cyanide m-chlorophenylhydrazone 10 min prior to addition of isotope. These data are from a single experiment but are representative of three independent assays.