Primer extensions were performed using the Thermoscript RT-PCR system (Invitrogen, Carlsbad, CA) with either PA4033 seq 1 or seq 2 with 10–20 μg of total RNA. Extensions were performed at 55°C for an hour. Primer extension products then were electrophoresed through a 6% acrylamide/8M urea gel along with sequencing reactions (Sequenase 2.0 kit, USB, Cleveland, OH) using the same primers used in the extension reactions. Transformation and conjugation E. coli One Shot TOP10 cells (Invitrogen) were transformed

via standard heat shock method according to the supplier’s instructions. Plasmid transfer from E. coli to Pseudomonas was performed via triparental conjugations using the helper plasmid GDC-0068 chemical structure pRK2013 [11]. Generating PAO1 miniCTX-P mucE -lacZ reporter strain PAO1 genomic DNA was used as a template to amply 618 CP673451 bp upstream of the start site

(ATG) of mucE using two primers with built-in restriction sites, HindIII-mucE-P-F (5′-AAA GCT TGG TCG TTG AAA GTC TGC ACC TCA-3′) and EcoRI-mucE-P-R: (5′-CGA ATT CGG TTG ATG TCA CGC AAA CGT TGG C-3′). The P mucE amplicon was TOPO cloned and digested with HindIII and EcoRI restriction enzymes before ligating into the promoterless Pseudomonas integration vector miniCTX-lacZ. The promoter fusion construct miniCTX-P mucE -lacZ was integrated onto the P. aeruginosa chromosome of strain PAO1 at the CTX phage att site [12] following triparental conjugation with E. coli containing the pRK2013 helper plasmid [11]. Screening for a panel check details of chemical agents that can promote P mucE transcription Membrane disrupters and antibiotics were first tested by serial dilution to determine the minimum inhibitory concentration (MIC) for strain PAO1::attB::P mucE Amisulpride -lacZ. An arbitrary sub-MIC concentration for each compound

was then tested for the induction effect through the color change of 5-Bromo-4-chloro-3-indolyl β-D-galactopyranoside (X-gal, diluted in dimethylformamide to a concentration of 4% (w/v)). The final concentration of the compounds used in this study are listed as follows: triclosan 25 μg/ml, tween-20 0.20% (v/v), hydrogen peroxide 0.15%, sodium hypochlorite 0.03%, SDS 0.10%, ceftazidimine 2.5 μg/ml, tobramycin 2.5 μg/ml, gentamicin 2.5 μg/ml, colisitin 2.5 μg/ml, and amikacin 2.5 μg/ml. PAO1::attB::P mucE -lacZ was cultured overnight in 2 ml LB broth, 10 μl of overnight culture and 10 μl of 4% X-gal was added to each treatment culture tube (2 ml LB broth + cell wall stress agent). The cultures were grown overnight at 37°C with shaking at 150 rpm and were used to visually observe the change of the color. LB broth lacking X-gal was used as a negative control. The β-galactosidase activity assay Pseudomonas strains were cultured at 37°C on three PIA plates. After 24 hours, bacterial cells were harvested and re-suspended in PBS. The OD600 was measured and adjusted to approximately 0.3.