TABLE 4.

Transcriptional analysis of promoter-lacZ fusions in C. diphtheriae C7(−) and C7(β)hm723 (dtxR) in high- and low-iron conditions

Clone/geneaβ-Galactosidase activity, unitsb (SD)
C7(−) (dtxR+)C7(β)hm723 (dtxR)
+Fe−FeRatio, −Fe/+Fe+Fe−FeRatio, −Fe/+Fe
CD-1/Zn-alcohol dehydrogenase16.1 (2.6)34.8 (3.6)2.263.1 (7.8)69.5 (2.5)1.1
CD-2/secY44.8 (4.6)61.1 (3.1)1.458.5 (2.0)54.6 (0.5)1.1
CD-3/deoR12.2 (1.4)12.5 (1.3)1.07.6 (1.4)6.3 (1.7)1.0
CD-4/recA23.7 (0.7)22.3 (0.9)1.032.5 (1.3)34.5 (4.8)1.0
CD-7-4/ywjA1.7 (0.2)1.6 (0.3)1.01.7 (0.1)1.7 (0.1)1.0
CD-20/piuB2.5 (0.4)10.5 (0.8)4.26.6 (1.8)7.3 (2.2)1.1
CD-40/chtA8.1 (2.2)268.4 (4.2)33.5572.4 (8.1)582.0 (25.4)1.0
CD-50/htaA4.6 (0.5)26.2 (2.2)5.731.1 (1.7)33.2 (2.3)1.0
CD-50/htaC25.4 (1.3)71.6 (4.5)2.8103.5 (5.7)100.4 (4.0)1.0
CD-frg/frgA44.2 (4.0)76.7 (1.6)1.795.9 (3.2)63.8 (10.8)0.7
CD-frg/frgD89.8 (4.9)299.0 (3.8)3.3302.1 (23.1)329.6 (18.2)1.1
CD-sid/sidA1.7 (0.4)26.1 (1.1)15.48.8 (1.8)21.5 (4.1)2.4
tox0.4 (0.1)98.7 (7.6)247.0109.4 (10.2)114.8 (4.5)1.0
  • a The first gene in the operon is indicated.

  • b β-Galactosidase units were determined as described previously (46). Values are the mean of three experiments ± standard deviation. +Fe is HIBTW medium, and −Fe is HIBTW with 70 μM EDDA.