TABLE 4.

YjeB-regulated promoters are derepressed by iron limitation

PromoterMean β-galactosidase activitya ± SD
− Dipyridyl+ 0.4 mM dipyridyl
ytfE81 ± 3.11,387 ± 164
hmpA143 ± 231,301 ± 57
ygbA162 ± 6744 ± 32
tehA2,084 ± 1021,172 ± 74
  • a Cultures were grown aerobically in L broth. Iron limitation was induced by the addition of 0.4 mM 2′2′-dipyridyl during log phase (this concentration is partially growth inhibitory), and β-galactosidase was assayed in early stationary phase (33). Units of activity are as defined by Miller (26).