TABLE 3.
Effect of gadE inactivation on expression of AFI and GAD genes in exponential and stationary phase
| IDa | Geneb | Function | Exponential-phase expression ratio (wild type/ΔgadE strain)
|
Stationary-phase expression ratio (wild type/ΔgadE strain)
|
||
|---|---|---|---|---|---|---|
| Microarray | Q-PCRc | Microarray | Q-PCRc | |||
| ECs4389 | hdeB | Periplasmic chaperone | 0.6 | 5.2 ± 2.0 | 2.8 | 31.4 ± 1.5 |
| ECs4390 | hdeA | Protection from organic acid metabolites | 0.3 | 3.2 ± 0.3 | 11.1 | 39.3 ± 3.0 |
| ECs4391 | hdeD | Acid resistance at high cell densities | 0.6 | 2.5 | ||
| ECs4397 | gadA | Glutamate decarboxylase isozyme | 0.4 | 2.2 ± 0.8 | 6.4 | 46.3 ± 13.7 |
| ECs2097 | gadC* | Glutamate-GABA antiporter | 0.5 | 2.3 ± 0.5 | 4.1 | 16 ± 0.9 |
| ECs2098 | gadB* | Glutamate decarboxylase isozyme | 0.4 | 2.2 ± 1.5 | 8.0 | 22.5 ± 1.67 |
a
Locus identification numbers (ID) for O157:H7 strain Sakai (GenBank accession no. BA000007).
b
Genes marked with an asterisk are GAD system genes not encoded in the AFI. Genes in boldface have putative GAD boxes upstream of the sequence.
c
Ratio ± SEM as determined by Q-PCR.