The NtrC family regulator AlgB, which controls alginate biosynthesis in mucoid Pseudomonas aeruginosa, binds directly to the algD promoter.

Alginate production in mucoid (MucA-defective) Pseudomonas aeruginosa is dependent upon several transcriptional regulators, including AlgB, a two-component response regulator belonging to the NtrC family. This role of AlgB was apparently independent of its sensor kinase, KinB, and even the N-terminal phosphorylation domain of AlgB was dispensable for alginate biosynthetic gene (i.e.

Cell wall-inhibitory antibiotics activate the alginate biosynthesis operon in Pseudomonas aeruginosa: Roles of sigma (AlgT) and the AlgW and Prc proteases.

A bioassay was developed to identify stimuli that promote the transcriptional induction of the algD operon for alginate biosynthesis in Pseudomonas aeruginosa. Strain PAO1 carried the algD promoter fused to a chloramphenicol acetyl-transferase cartridge (PalgD-cat), and > 50 compounds were tested for promoting chloramphenicol resistance. Most compounds showing PalgD-cat induction were cell wall-active antibiotics that blocked peptidoglycan synthesis.

Effect of site-specific mutations in different phosphotransfer domains of the chemosensory protein ChpA on Pseudomonas aeruginosa motility.

The virulence of Pseudomonas aeruginosa and other surface pathogens involves the coordinate expression of a wide range of virulence determinants, including type IV pili. These surface filaments are important for the colonization of host epithelial tissues and mediate bacterial attachment to, and translocation across, surfaces by a process known as twitching motility. This process is controlled in part by a complex signal transduction system whose central component, ChpA, possesses nine potential sites of phosphorylation, including six histidine-containing phosphotransfer (HPt) domains, one serine-containing phosphotransfer domain, one threonine-containing phosphotransfer domain, and one CheY-like receiver domain.

Sub-inhibitory concentrations of ceftazidime and tobramycin reduce the quorum sensing signals of Pseudomonas aeruginosa.

Aim: Concentrations of antimicrobials below minimum inhibitory concentration (subMIC) may reduce the production by Pseudomonas aeruginosa of virulence factors such as elastase. We sought to determine whether the reduction in elastase production may be mediated by a reduction in acyl-homoserine lactones.

Methods: Pseudomonas aeruginosa in broth was exposed to three conditions for ceftazidime and tobramycin: control, 6% MIC and 25% MIC.

Characterization of a complex chemosensory signal transduction system which controls twitching motility in Pseudomonas aeruginosa.

Virulence of the opportunistic pathogen Pseudomonas aeruginosa involves the coordinate expression of a wide range of virulence factors including type IV pili which are required for colonization of host tissues and are associated with a form of surface translocation termed twitching motility. Twitching motility in P. aeruginosa is controlled by a complex signal transduction pathway which shares many modules in common with chemosensory systems controlling flagella rotation in bacteria and which is composed, in part, of the previously described proteins PilG, PilH, PilI, PilJ and PilK.

Identification of a novel gene, fimV, involved in twitching motility in Pseudomonas aeruginosa.

Transposon mutagenesis was used to identify a new locus required for twitching motility in Pseudomonas aeruginosa. Four Tn5-B21 mutants which lacked twitching motility and a fifth which exhibited impaired motility were found to map to the same KPN:I restriction fragment at approximately 40 min on the P. aeruginosa genome.