Genome wide transcriptional analysis of P. aeruginosa PAO1 response to kappa-opioid U-50,488 in poor nutrient medium

Here we examined virulence activation in Pseudomonas aeruginosa in response to the synthetic kappa opioid agonist U-50, 488 in nutrient poor media where growth conditions are limited and density dependent quorum sensing is not activated. We used a microarray to define the virulence-related genes in P. aeruginosa grown in liquid poor nutrient medium to determine the effect of kappa-opioid receptor agonist on virulence/lethal phenotype All biological samples for gene expression analysis were prepared in triplicate. P. aeruginosa MPAO1 cells collected from liquid culture at 7 hrs of growth in 1.) 0.1xTY medium containing tryptone 1 g/L and yeast extract, 0.5 g/L, or 2.) 0.1xTY+25 mM potassium phosphate buffer, pH 6.0, or 3.) 0.1xTY+200 uM U-50,488, or 4.) 0.1xTY+ 25 mM potassium phosphate buffer, pH 6.0+ 200 uM U-50,488 were used for RNA isolation. Microarray analysis was performed using Affymetrix P. aeruginosa GeneChips (Affymetrix, Santa Clara, CA) at the University of Chicago Functional Genomics Facility