TABLE 1.

Transcriptional activation of bfeA and BfeA-dependent growth stimulation by catechol compounds

Compoundβ-Galactosidase activity (Miller units) of B013N(pMP3) (bfeA-lacZ):Fold inductionaBfeA-dependent growth stimulation
Without FeWithout Fe and with compound (50 μM)
Siderophores
    Enterobactin42.6 (±5.1)b1,531.5 (±123.9)36.0+c
    Salmochelin57.1 (±4.6)182.9 (±11.9)3.2+
    Corynebactin54.8 (±7.8)91.3 (±19.1)1.7+/−d
    DHBS17.2 (±10.7)15.5 (±10.9)eNGf
Synthetic analogs
    MECAM27.3 (±3.1)459.5 (±24.6)16.8+/−
    TRENCAM58.5 (±7.7)88.8 (±7.9)1.5+
Catechols
    Pyrocatechol55.2 (±3.8)1,600.8 (±55.0)29.0NG
    3,4-Dihydroxymandelic acid55.2 (±3.8)162.4 (±5.9)2.9NG
  • a LacZ activity without Fe and with compound ÷ LacZ activity without Fe.

  • b ±1 standard deviation.

  • c +, BfeA dependent.

  • d +/−, partially BfeA dependent; growth stimulation of a bfeA strain was reduced compared to that of the wild-type strain.

  • e −, no induction.

  • f NG, no growth.