Pseduomonas aeruginosa PAO1 exposed to subinhibitory colistin
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ABSTRACT:
ORGANISM(S): Pseudomonas aeruginosa Pseudomonas aeruginosa PAO1
PROVIDER: GSE13252 | GEO | 2009/09/01
SECONDARY ACCESSION(S): PRJNA109535
REPOSITORIES: GEO
Similar Datasets
Project description:Colistin is an important cationic antimicrobial peptide (CAMP) in the fight against Pseudomonas aeruginosa infection within the cystic fibrosis (CF) lungs. The effects of sub-inhibitory colistin on gene expression in P. aeruginosa were investigated by transcriptome microarray and functional analysis. Analysis revealed an alteration in the expression of 60 genes in total from a variety of pathways. Genes associated with bacterial chronic colonisation and virulence such as response to osmotic stress, motility, and biofilm formation, as well as those associated with LPS modification and quorum sensing are the most highly represented. Most striking among these is the upregulation of the PQS biosynthesis operon including pqsH, pqsE, and the anthranilate biosynthetic genes phnAB. Early activation of this central component of the QS-network may represent a switch to a more robust population, with increased fitness in the competitive environment of the CF-lung. Experiment Overall Design: Three independent cultures of the P. aeruginosa strain PAO1 were exposed to 0.15 µg colistin mlâ1. The untreated and treated samples were grown from OD600 0.05 to 0.8 and subsequently total RNA was extracted using the Ambion RiboPureTm- Bacteria kit according to the manufacturerâs instructions.
2009-09-12 | E-GEOD-13252 | biostudies-arrayexpress
Project description:Pseudomonas aeruginosa pathogenicity mainly relies on its ability to finely control the expression of virulence determinants via multiple quorum sensing (QS) systems. Despite the relevant role of the pqs QS system in controlling the expression of key virulence factors and biofilm formation in P. aeruginosa, our understanding of the molecular mechanisms governing this QS circuit, which employs 2-alkyl-4-quinolones (AQs) as signal molecules, is still preliminary, probably due to its complexity. Multiple genes are required for the synthesis of the primary AQs, 2-heptyl-4-hydroxyquinoline (HHQ), 2-heptyl-3-hydroxy-4-quinolone (PQS), and 2-heptyl-4-hydroxyquinoline N-oxide (HQNO). These include the pqsABCDE operon, required for the synthesis of HHQ, which in turn is oxidized to PQS via the action of the monooxygenase PqsH. The monooxygenase PqsL is required for HQNO synthesis together with the pqsABCD genes. The fifth gene of the pqsABCDE operon, pqsE, is also required for the production of major virulence factors and for biofilm formation, and exerts a homeostatic effect on AQs synthesis by repressing the transcription of the pqsABCDE operon. The pqs system is subject to positive autoregulation, with the PqsR regulator promoting pqsABCDE transcription upon binding to HHQ or PQS. However, the individual contributions and relative importance of HHQ, PQS, HQNO and PqsE to AQ-dependent signalling is not fully apparent, because of the overlapping and interdependent nature of the factors involved in this complex QS network. We used microarrays to detail the global response of a P. aeruginosa mutant strain unable to synthesise or convert AQs, and to express PqsE to exogenously provided AQs or IPTG (to induce pqsE expression).
2020-11-21 | GSE81364 | GEO
Project description:Pseudomonas aeruginosa PA14, pqsE and PQS
| PRJNA123657 | ENA
Project description:The Pseudomonas aeruginosa MvfR-dependent QS regulatory pathway controls the expression of key virulence genes; and is activated via the extracellular signals 4-hydroxy-2-heptylquinoline (HHQ) and 3,4-dihydroxy-2-heptylquinoline (PQS). Our findings reveal a multi-layered homeostatic regulation of PQS and HHQ and the MvfR regulon component PqsE which is a key mediator in orchestrating this homeostatic regulation.
2009-07-17 | GSE17116 | GEO
Project description:Pseudomonas aeruginosa is a major cause of nosocomial infections and also leads to severe exacerbations in cystic fibrosis or chronic obstructive pulmonary disease. Three intertwined quorum sensing systems control virulence of P. aeruginosa, with the rhl circuit playing the leading role in late and chronic infections. The majority of traits controlled by rhl transcription factor RhlR depend on PqsE, a dispensable thioesterase in Pseudomonas Quinolone Signal (PQS) biosynthesis that interferes with RhlR through an enigmatic mechanism likely involving direct interaction of both proteins. Here we show that PqsE and RhlR form a 2:2 protein complex that, together with RhlR agonist N-butanoyl-L-homoserine lactone (C4-HSL), solubilizes RhlR and thereby renders the otherwise insoluble transcription factor active. We determined crystal structures of the complex and identified residues essential for the interaction. To corroborate the chaperone like activity of PqsE, we designed stability-optimized variants of RhlR that bypass the need for C4-HSL and PqsE in activating PqsE/RhlR-controlled processes of P. aeruginosa. Together, our data provide insight into the unique regulatory role of PqsE and lay groundwork for developing new P. aeruginosa-specific pharmaceuticals.
2023-03-11 | PXD038000 | Pride
Project description:The opportunistic pathogen Pseudomonas aeruginosa has complex quorum sensing (QS) circuitry, which involves two acylhomoserine lactone (AHL) systems, the LasI AHL synthase and LasR AHL-dependent transcriptional activator system and the RhlI AHL synthase-RhlR AHL-responsive transcriptional activator. There is also a quinoline signaling system (the Pseudomonas quinolone signal, PQS, system). Although there is a core set of genes regulated by the AHL circuits, there is substantial strain-to-strain variation in the non-core QS regulated genes. Reductive evolution of the QS regulon, and variation in specific genes activated by QS occurs in laboratory evolution experiments with the model strain PAO1. We used a transcriptomics approach to test the hypothesis that reductive evolution in the PAO1 QS regulon can in large part be explained by a simple null mutation in pqsR, the gene encoding the transcriptional activator of the pqs operon. We found that PqsR had very little influence on the AHL QS regulon. This was a surprising finding because the last gene in the PqsR-dependent pqs operon, pqsE, codes for a protein, which physically interacts with RhlR and this interaction is required for full RhlR-dependent activation of some genes. We used comparative transcriptomics to examine the influence of a pqsE mutation on the QS regulon and identified only three transcripts, which were strictly dependent on PqsE. By using reporter constructs we showed that the PqsE influence on other genes was dependent on experimental conditions and we have gained some insight about those conditions. This work adds to our understanding of the plasticity of the P. aeruginosa QS regulon and to the role PqsE plays in RhlR-dependent gene activation.
2024-03-17 | GSE261453 | GEO
Project description:Virulence factor production and the development of biofilms in Pseudomonas aeruginosa have been shown to be regulated by two hierarchically organised quorum sensing (QS) systems via small acyl-homoserine lactone (AHL) signal molecules. Recently, a third bacterial signal molecule, the Pseudomonas quinolone signal (PQS), has been identified, which positively regulates a subset of genes dependent on the QS systems. To further dissect the various independent regulation levels for many QS induced genes and to evaluate the impact of PQS on the QS circuitry, we performed a transcriptome analysis of PAO1 cultures supplemented with PQS. The global transcriptional profile in response to PQS revealed a marked up-regulation of genes belonging to the tightly interdependent functional groups of iron acquisition and oxidative stress response. Remarkably, not only most of the differentially regulated genes but also the induction of a lacZ transcriptional fusion of rhlR could be traced back to a iron chelating effect of PQS. Nevertheless, although iron deficiency per se induced rhlR, there seems to be PQS specific effects that are independent of the PQS effect on P. aeruginosa iron homeostasis Keywords: PQS response
2006-12-12 | GSE3836 | GEO
Project description:To see the effects of tobramycin on Pseudomonas aeruginosa under anaerboc lethal conditions. RNA was isolated from 5 biological repeats of P.aeruginosa grown in cationic adjusted mueller hinton broth containing 15mM KNO3 and 5 biological repeats of P.aeruginosa grown in cationic adjusted mueller hinton broth containing 15mM KNO3 after being treated with 20 ug/ml tobramycin for 30 minutes.
2011-01-20 | E-FPMI-24 | biostudies-arrayexpress
Project description:Pseudomonas aeruginosa (P. aeruginosa) lung infection is a significant cause of mortality in patients with cystic fibrosis (CF). Most CF patients acquire unique P. aeruginosa strains from the environment; however clonal strains have been identified in CF communities in several countries. Two clonal strains infect 10% to 40% of patients in three CF clinics in mainland eastern Australia. The expression profiles of four planktonically-grown isolates of one Australian clonal strain (AES-1), and four non–clonal CF P. aeruginosa isolates were compared to each other and to the reference strain PAO1 using the Affymetrix P. aeruginosa PAO1 genome array, to gain insight into properties mediating the enhanced infectivity of AES-1. The isolates were subsequently grown as 3-day old biofilms and similarly extracted for RNA and compared as above. Data analysis was carried out using BIOCONDUCTOR software. Keywords: Comparative strain hybridization
2008-12-05 | GSE6122 | GEO
Project description:Virulence factor production and the development of biofilms in Pseudomonas aeruginosa have been shown to be regulated by two hierarchically organised quorum sensing (QS) systems via small acyl-homoserine lactone (AHL) signal molecules. Recently, a third bacterial signal molecule, the Pseudomonas quinolone signal (PQS), has been identified, which positively regulates a subset of genes dependent on the QS systems. To further dissect the various independent regulation levels for many QS induced genes and to evaluate the impact of PQS on the QS circuitry, we performed a transcriptome analysis of PAO1 cultures supplemented with PQS. The global transcriptional profile in response to PQS revealed a marked up-regulation of genes belonging to the tightly interdependent functional groups of iron acquisition and oxidative stress response. Remarkably, not only most of the differentially regulated genes but also the induction of a lacZ transcriptional fusion of rhlR could be traced back to a iron chelating effect of PQS. Nevertheless, although iron deficiency per se induced rhlR, there seems to be PQS specific effects that are independent of the PQS effect on P. aeruginosa iron homeostasis Experiment Overall Design: For RNA extraction bacteria were harvested at early logarithmic, late logarithmic and stationary phase of growth. Three independent cultures of PQS-treated and untreated PAO1 each were pooled and the RNA was immediately stabilized with RNAprotect Bacteria Reagent (Qiagen, Valencia, CA). RNA was isolated using the RNeasy kit (Qiagen), treated with DNaseI (Roche) for 30 min at 37M-BM-0C and re-purified with the RNeasy spin column. The subsequent steps of cDNA generation and Biotin-ddUTP terminal labelling were performed as described in the manufacturerM-bM-^@M-^Ys instructions for the P. aeruginosa GeneChipM-CM-^R. Fragmented and labelled cDNA was hybridised to a GeneChip at 50 M-BM-0C for 16 h. The washing steps, staining and scanning of the microarrays were performed using the Affymetrix GeneChip system. Data analysis was performed using the Affymetrix Microarray Suite Software 5.0 with Affymetrix default parameters. As expression analysis was performed in duplicate, a total of two GeneChips per culture condition was scanned at 570 nm, 3 M-BM-5m resolution in an Affymetrix GeneChip scanner. The signals were multiplied by a scaling factor to make the average signal for all the arrays equivalent. The data were imported into a Microsoft Access database capable of searching for genes, which were found in all four pairings defined by the Affymetrix Microarray Suite Software as having significant changes in their signal intensities. Data were combined with the latest annotation from the website of the P. aeruginosa PAO1 sequence and the community annotation project provided at www.pseudomonas.com.
2008-11-07 | E-GEOD-3836 | biostudies-arrayexpress