TABLE 3.
Suppression of the MTX sensitivities of TolC mutants by cI-DHFR
| Line | Strainb | Fusion protein | tolC genotype | Growtha
|
|||
|---|---|---|---|---|---|---|---|
| −IPTG
|
+IPTG
|
||||||
| −MTX | +MTX | −MTX | +MTX | ||||
| 1 | AG1688 | None | tolC+ | + | + | + | + |
| 2 | SK037 | None | tolC mutant | + | − | + | − |
| 3 | SK029 | cI-DHFR | tolC+ | + | + | + | + |
| 4 | SK029 tolC::Tn10 | cI-DHFR | tolC mutant | + | − | + | + |
| 5 | XZ020 | cI-GCN4 | tolC+ | + | + | + | + |
| 6 | XZ020 tolC::Tn10 | cI-GCN4 | tolC mutant | + | − | + | − |
a
Cultures were grown to saturation in Luria-Bertani broth at 37°C overnight and diluted in M9 salts to approximately 5,000 CFU/ml. A total of 10 μl of each diluted culture was pipetted onto Luria-Bertani agar plates containing no IPTG (−IPTG) or 1 mM IPTG (+IPTG) and either no MTX (−MTX) or 1 mM MTX (+MTX) as indicated. The spots were allowed to dry and then the plates were incubated at 37°C overnight. +, growth; −, no growth. The observations are from at least three separate experiments.
b
tolC::Tn10 was introduced into the indicated strains by P1 vir transduction using KH803 as the donor.