Identification of Pseudomonas aeruginosa genes involved in virulence and anaerobic growth.

Pseudomonas aeruginosa is a gram-negative, opportunistic pathogen and a significant cause of acute and chronic infections in patients with compromised host defenses. Evidence suggests that within infections P. aeruginosa encounters oxygen limitation and exists in microbial aggregates known as biofilms.

Microarray analysis of Pseudomonas aeruginosa quorum-sensing regulons: effects of growth phase and environment.

Bacterial communication via quorum sensing (QS) has been reported to be important in the production of virulence factors, antibiotic sensitivity, and biofilm development. Two QS systems, known as the las and rhl systems, have been identified previously in the opportunistic pathogen Pseudomonas aeruginosa. High-density oligonucleotide microarrays for the P.

LasR, a transcriptional activator of Pseudomonas aeruginosa virulence genes, functions as a multimer.

The Pseudomonas aeruginosa LasR protein functions in concert with N-3-oxo-dodecanoyl-L-homoserine lactone (3O-C(12)-HSL) to coordinate the expression of target genes, including many genes that encode virulence factors, with cell density. We used a LexA-based protein interaction assay to demonstrate that LasR forms multimers only when 3O-C(12)-HSL is present. A series of LasR molecules containing internal deletions or substitutions in single, conserved amino acid residues indicated that the N-terminal portion of LasR is required for multimerization.