TABLE 4.
Transcriptional analysis of promoter-lacZ fusions in C. diphtheriae C7(−) and C7(β)hm723 (dtxR) in high- and low-iron conditions
| Clone/genea | β-Galactosidase activity, unitsb (SD)
|
|||||
|---|---|---|---|---|---|---|
| C7(−) (dtxR+)
|
C7(β)hm723 (dtxR)
|
|||||
| +Fe | −Fe | Ratio, −Fe/+Fe | +Fe | −Fe | Ratio, −Fe/+Fe | |
| CD-1/Zn-alcohol dehydrogenase | 16.1 (2.6) | 34.8 (3.6) | 2.2 | 63.1 (7.8) | 69.5 (2.5) | 1.1 |
| CD-2/secY | 44.8 (4.6) | 61.1 (3.1) | 1.4 | 58.5 (2.0) | 54.6 (0.5) | 1.1 |
| CD-3/deoR | 12.2 (1.4) | 12.5 (1.3) | 1.0 | 7.6 (1.4) | 6.3 (1.7) | 1.0 |
| CD-4/recA | 23.7 (0.7) | 22.3 (0.9) | 1.0 | 32.5 (1.3) | 34.5 (4.8) | 1.0 |
| CD-7-4/ywjA | 1.7 (0.2) | 1.6 (0.3) | 1.0 | 1.7 (0.1) | 1.7 (0.1) | 1.0 |
| CD-20/piuB | 2.5 (0.4) | 10.5 (0.8) | 4.2 | 6.6 (1.8) | 7.3 (2.2) | 1.1 |
| CD-40/chtA | 8.1 (2.2) | 268.4 (4.2) | 33.5 | 572.4 (8.1) | 582.0 (25.4) | 1.0 |
| CD-50/htaA | 4.6 (0.5) | 26.2 (2.2) | 5.7 | 31.1 (1.7) | 33.2 (2.3) | 1.0 |
| CD-50/htaC | 25.4 (1.3) | 71.6 (4.5) | 2.8 | 103.5 (5.7) | 100.4 (4.0) | 1.0 |
| CD-frg/frgA | 44.2 (4.0) | 76.7 (1.6) | 1.7 | 95.9 (3.2) | 63.8 (10.8) | 0.7 |
| CD-frg/frgD | 89.8 (4.9) | 299.0 (3.8) | 3.3 | 302.1 (23.1) | 329.6 (18.2) | 1.1 |
| CD-sid/sidA | 1.7 (0.4) | 26.1 (1.1) | 15.4 | 8.8 (1.8) | 21.5 (4.1) | 2.4 |
| tox | 0.4 (0.1) | 98.7 (7.6) | 247.0 | 109.4 (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.