Table 6.
Phenotypes of the χ289, χ316, χ444, and χ453 strains
| Straina | DadA activityb | Succinate utilizationc | Erm sensitivity (mm)d | DCS sensitivity (mm)d on: |
|
|---|---|---|---|---|---|
| MOPS glycerol | LB | ||||
| χ289 | 45.6 (±3.5) | Yes | 10.4 (±0.6) | 64.4 (±2.7) | 12.6 (±0.6) |
| χ316 | 47.0 (±3.3) | Yes | 11.0 (±0.6 | 16.3 (±0.7) | 12.6 (±0.5) |
| χ444 | 2.4 (±1.1) | Yes | 10.7 (±0.4) | Resistant | Resistant |
| χ453 | 2.0 (±0.8) | Yes | 10.5 (±0.7) | Resistant | Resistant |
| BW25113 | 61.9 (±10.9) | Yes | 12.0 (±1.5) | 67.1 (±1.3) | 13.1 (±0.3) |
| BW25113 dadA | 3.0 (±2.4) | Yes | 11.4 (±0.3) | 46.2 (±2.6) | Resistant |
| BW25113 pnp | 79.9 (±12.3) | Yes | 23.6 (±1.6) | 63.4 (±2.2) | Resistant |
| BW25113 ubiF | ND | No | ND | ND | Resistant |
χ Strains are from Curtiss et al.'s study of DCS resistance in E. coli (11). The gene name represents the Keio strain identified in the DCS resistance screen. BW25113 is the parent of the Keio strain collection.
d-Alanine dehydrogenase (DadA) activity is reported as OD520/h/mg of total protein. Each data point represents the average and the resulting standard deviations from three experimental replicates.
From an overnight culture, each strain was streaked onto a MOPS succinate agar plate and incubated at 37°C for 24 h. Growth was determined by visual inspection.
Antibiotic sensitivity was determined by antibiotic disk diffusion assay on LB plates. For erythromycin sensitivity assays, 20 μg of erythromycin was added to each disk. For DCS sensitivity assays, a 10-μl aliquot from a 24.5 mM solution of DCS was added to each disk. Each data point represents the average zone of growth inhibition and the resulting standard deviations from three experimental replicates.