The effect of 2-AA on P. aeruginosa PA14 and its mutants
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ABSTRACT:
ORGANISM(S): Pseudomonas aeruginosa Pseudomonas aeruginosa PA14
PROVIDER: GSE24036 | GEO | 2011/12/21
SECONDARY ACCESSION(S): PRJNA130335
REPOSITORIES: GEO
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Project description:The pqs operon of the bacteria P. aeruginosa is responsible for the production of at least 60 secreted compounds mainly hidroxy-quinolones (HAQs). Some of them, like PQS and HHQ, were found to be important signal that control the virulence of the bacteria. We have discover that one of the most abandon molecule produced by the pqs operon, 2 aminoacetophenone (2-AA), a volatile molecule serves as a unique signal. In contrast to the previous described PQS and HHQ, 2-AA is downregulating virulence and acute phase proteins and upregulating chronic phase proteins. In addition we have found that 2-AA promotes the formation of persisters cells that antibiotic tolerant. we have compared the genes profile of wild-type PA14 strain and its derivatives topA which lacks Topoisomerase I and pqsA that do not produces HAQs or 2-AA to cultures that were treated with 3mM of 2-AA. Cell were grown with and without 2-AA (3mM) to OD 2.0.
2011-12-21 | E-GEOD-24036 | 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: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: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), whose syntheses depend on anthranilic acid (AA), the primary precursor of 4-hydroxy-2-alkylquinolines (HAQs). We identified halogenated AA analogs that specifically inhibited HAQ biosynthesis and disrupted MvfR-dependent gene expression. These compounds restricted P. aeruginosa systemic dissemination and mortality in mice, without perturbing bacterial viability, and inhibited osmoprotection, a widespread bacterial function.
2009-07-17 | GSE17111 | GEO
Project description:To establish infections in human hosts, P. aeruginosa must overcome innate immune generated oxidative stress, such as the hypochlorous acid (HOCl) produced by neutrophils. We set out to find specific metabolomic biomarkers of oxidative stress and we developed a protocol for the metabolic profiling of P. aeruginosa cultures grown in the presence of different oxidants using a novel ionisation technique for mass spectrometry, laser-desorption rapid evaporative ionisation mass spectrometry (LD-REIMS). We demonstrate the ability of LD-REIMS to classify samples as untreated or treated with a specific oxidant with 100 % accuracy and identified a panel of 54 metabolites with significantly altered concentrations after exposure to one or more of the oxidants. Key metabolic changes were conserved in P. aeruginosa clinical strains isolated from patients with cystic fibrosis lung infections. These data demonstrate that HOCl stress impacted the Pseudomonas Quinolone Signal (PQS) quorum sensing system. Ten 2-alkyl-4-quinolones (AHQs) associated with the PQS system were significantly lower in concentration in HOCl-stressed P. aeruginosa cultures, including 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS), the most active signal molecule of the PQS system. The PQS system regulates the production of virulence factors, including pyocyanin and elastase, and their levels were markedly affected by HOCl stress. No pyocyanin was detectable and elastase concentrations were significantly reduced in cultures grown with sub-lethal concentrations of HOCl, suggesting that this neutrophil-derived oxidant may disrupt the ability of P. aeruginosa to establish infections through interference with production of PQS-associated virulence factors.
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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: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
Project description:In order to determine how the bacterial quorum-sensing precursor molecule 2-heptyl-4-quinolone (HHQ) induces cellular senescence in populations of some eukaryotic marine phytoplankton, we examined the transcriptional response of Emiliania huxleyi CCMP2090 to HHQ exposure. Quadruplicate batch cultures were treated with HHQ at three concentrations (1, 10 and 100 ng/ml) and compared to a vehicle control after 24 and 72 hours of exposure. The majority of gene expression changes occurred after 24 hr of exposure in the 10 and 100 ng/ml treatments and many of these changes persisted for 72 hr in the 100 ng/ml treatment. RNAseq analysis revealed that HHQ exposure impacts many aspects of Emiliania huxleyi metabolism including: chlorophyll biosynthesis and light harvesting, vitamin biosynthesis, vesicle trafficking, and general signals related to energy production. Changes in genes involved in intraphase cell cycle check points implicate DNA damage as the primary driver of HHQ-induced cellular senescence.
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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.
2011-12-21 | GSE24038 | GEO
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.
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