TABLE 1.
Sensitivities to antimicrobial agents of strains of an E. coli BL21 tolC mutant (BL21-2) harboring the indicated plasmids
| Plasmid | Formation of a halo in the presence ofa:
|
||
|---|---|---|---|
| Acriflavine | Novobiocin | ColE1 | |
| pET11-STI | +++ | +++ | − |
| pET11-STI-TolC | − | − | +++ |
| pET11-STI-TolC(ΔC20) | − | − | +++ |
| pET11-STI-TolC(ΔC30) | − | − | +++ |
| pET11-STI-TolC(ΔC40) | − | − | +++ |
| pET11-STI-TolC(ΔC50) | − | − | +++ |
| pET11-STI-TolC(ΔC60) | +++ | +++ | − |
| pET11-STI-TolC(L412P) | +++ | +++ | − |
a
A drop of cell suspension (approximately 108 cells/ml) was spread on an L agar plate containing ampicillin (50 μg/ml). Sterile blank disks (6.4 mm in diameter) were placed on a lawn. The solution containing antimicrobial reagent was pipetted onto each disk. The plates were allowed to incubate overnight at 37°C. The halos (growth inhibition zone) obtained were classified into four groups according to size. −, diameter of less than 8 mm; +++, diameter greater than than 18 mm.