Plasmid pGP704L/ttgC::Sm was selected in E. coli strain CC118 λpir and the interrupted ttgC gene was

inserted into the chromosome of P. putida PaW85 and PaWcolR by homologous recombination. For disruption of the click here ttgB, the 5′ end of the gene was amplified with oligonucleotides ttgBXba (5′-CAATCTAGAACTGCGCCAGCTCAAGGC) and ttgBSac (5′-CCCGAGCTCTGTTCCATCGAGCGTTTG) and cloned into Eco32I-opened pBluescript KS (Stratagene). The cloned ttgB sequence was disrupted by replacing of a central 735-bp EheI fragment with Smr gene and the resulting ttgB::Sm sequence was subcloned into pGP704L as a XbaI-SacI fragment. Finally, the interrupted ttgB gene was inserted into the chromosome of P. putida PaW85 and PaWcolR by homologous recombination. Measurement of unmasked β-galactosidase activity β-galactosidase this website activities were measured

from solid medium-grown bacteria. As a source of β-galactosidase, the plasmid pKTlacZS/C containing the tnpA promoter of the transposon Tn4652 in front of the lacZ gene, was used [25]. Bacteria grown overnight on solid glucose M9 minimal medium or on the same medium supplemented with 1 mM phenol were see more scraped off from the plates using plastic swabs. Cells were suspended in M9 solution and optical density of the suspension was determined at OD580. β-galactosidase activity was measured using two alternative procedures. In one procedure, SDS and chloroform were added to the reaction to permeabilize bacterial cell membrane as described previously [26]. In a parallel experiment SDS and chloroform were not added. Percentage of unmasked β-galactosidase activity was calculated by equation: xn/xp × 100%, where xp is β-galactosidase activity measured in assay with SDS and chloroform, and xn is β-galactosidase activity measured using non-permeabilized cells. Phenol tolerance assay on solid medium Phenol sensitivity

was evaluated on agar plates containing 10 mM glucose or 10 mM gluconate as carbon sources, and up to 10 mM phenol (specified in the Fig. 1). Approximately 1 × 105 cells were spotted onto plates as 5 μl drops and plates were incubated at 30°C for 48 hours. Figure 1 also Plate assay of phenol tolerance. Results of P. putida PaW85 (wt), colS-deficient (colS), colR-deficient (colR), ttgB-deficient (ttgB), ttgC-deficient (ttgC), colRttgB double mutant (colRttgB) and colRttgC double mutant (colRttgC) strains are presented. Approximately 1 × 105 cells were spotted onto solid medium and plates were incubated at 30°C for 48 hours. The minimal media contained either 10 mM glucose or 10 mM gluconate as the carbon source. Concentration of added phenol is indicated below the figures. Phenol mediated killing assay Bacteria were pre-grown on solid glucose minimal plates for 24 hours. Cells were scraped off from the plates and suspended in M9 buffer containing 10 mM glucose and microelements. Optical density of cell suspension was adapted to 0.2 at OD580.