Table 2.

Iron transport systems in E. coli CFT073 and its isogenic iron uptake mutants

StrainaFeSO4utilizationbHemin utilizationbAerobactinEnterobactin
Synthesis TransportbSynthesisTransportb
CFT073+ + + + + +
CFT073-TB + + +
CFT073-TB(pYUK1) + + + + + +
CFT073-LH+ c + + + +
CFT073-ENT + + + + +
CFT073-IUC+ + + + +
CFT073-ENT/IUC + ++ +
CFT073-IUT + + + ++
  • a Abbreviations: -TB, tonB; -LH, chuA; -ENT, entF; -IUC, iucB; -ENT/IUC, entF iucB; -IUT, iutA; pYUK1, TonB+ plasmid.

  • b Bioassays were performed by seeding the strain in L-EDDA agar and spotting the indicated compound on the surface of the plate. + indicates a zone of growth around the iron compound. − indicates no stimulation of growth. Synthesis of siderophores was determined by chemical assays and bioassays.

  • c A small amount of background growth was observed on occasion.