Project description:MvaT and MvaU are two redundant xenogeneic silencing proteins of the H-NS family in Pseudomonas aeruginosa. Previous studies to investigate the physiological consequences of mvaT and mvaU depletion were hampered by activation of Pf4 prophage in the resulting mutants. In this study, an mvaT mvaU double knockout mutant (PAO△TU) was constructed in a strain of PAO1 (Δpf4) devoid of the Pf4 prophage on the chromosome.Transcriptome analysis by GeneChip (Affymetrix) revealed that over 227 genes were found up-regulated in PAO△TU, including several multi-gene loci for type III and type VI protein secretion systems, O-antigen, exopolysaccharide, pili assembly, and many others of unknown functions.
Project description:Manuscript Title: Pyochelin biotransformation shapes bacterial competition LC-MS/MS analysis of P. aeruginosa interaction with S. aureus wildtype, fhuG mutant and fhuD1/D2 double mutant.
Project description:We present here a transcriptional regulator, PA3898, which controls biofilm formation and multidrug efflux-pumps in P. aeruginosa. A mutant of this regulator significantly reduced the ability of P. aeruginosa to produce biofilm in vitro, and affected its in vivo fitness and pathogenesis in Drosophila melanogaster and BALB/c mouse lung infection models. Transcriptome analysis revealed that PA3898 modulates essential virulence genes/pathways, including multidrug efflux-pumps and phenazine biosynthesis.
Project description:Manuscript Title: Pyochelin biotransformation shapes bacterial competition
LC-MS/MS analysis of P. aeruginosa interaction with S. aureus wildtype, spm mutant and spm complemented mutant.
Project description:In this study, we present a novel transcriptional regulator, PA1226, which modulates biofilm formation and virulence in P. aeruginosa. Mutation in this regulator abolished the ability of P. aeruginosa to produce biofilm in vitro, without any effect on the planktonic growth. This regulator is essential to the in vivo fitness and pathogenesis in both Drosophila melanogaster and BALB/c mouse lung infection models. Transcriptome analysis revealed that PA1226 regulates many essential virulence genes/pathways, including alginate, pili, and LPS biosynthesis.
Project description:The transcriptional regulator AmpR controls expression of the AmpC ß-lactamase in P. aeruginosa and other bacteria. Studies have demonstrated that in addition to regulating ampC expression, AmpR also regulates the expression of the sigma factor AlgT/U and the production of some quorum-sensing regulated virulence factors. In order to understand the ampR regulon, we compared the expression profiles of PAO1 and its isogenic ampR mutant, PAO∆ampR in the presence and absence of sub-MIC ß-lactam stress. The analysis demonstrates that the ampR regulon is much more extensive than previously thought, with the deletion of ampR affecting the expression of over 300 genes. Expression of an additional 207 genes are affected by AmpR when the cells are exposed to sub-MIC ß-lactam stress, indicating that the ampR regulon in P. aeruginosa is much more extensive than previously thought.
Project description:To gain insights into the initial phases of P. aeruginosa infections and to identify P. aeruginosa genes regulated in response to respiratory epithelia we exposed P. aeruginosa to cultured primary differentiated human airway epithelia. We used a P. aeruginosa strain (PAO1) that causes acute damage to the epithelia and a mutant (PAOSC11) with defects in Type III secretion and in rhamnolipid synthesis. The mutant did not cause rapid damage to epithelia as did the wildtype. Keywords: Pseudomonas aeruginosa and respiratory epithelia
Project description:We have tested the effect of deletion of Topoisomerase I on genes transcription of the bacteria Pseudomonas. aeruginosa. Topoisomerase I is a conserved protein that modulate the topology state of the DNA from super-coiled to relaxed. To this end we have compared the transcription profile of a topA::GentR mutant to that of the wild-type strain. The topA mutant contains in topA gene a Mariner transposon with a gentamicin resistance cassette. It is part of the non-redundant mutant library of P. aeruginosa PA14 strains.