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SRP041150
Pseudomonas aeruginosa
2 Downloadable Samples
Illumina HiSeq 1000
Description
Aim of this project was to determine the transcriptional response of the isolate PA30 to tap water and waste water.
Publication Title
Whole genome and transcriptome analyses of environmental antibiotic sensitive and multi-resistant Pseudomonas aeruginosa isolates exposed to waste water and tap water.
Sample Metadata Fields
Specimen part
View Samples- Pseudomonas aeruginosa
- 2 Downloadable Samples
- Illumina HiSeq 1000
Description
Aim of this project was to determine the transcriptional response of the isolate PA49 to tap water and waste water.
Publication Title
Whole genome and transcriptome analyses of environmental antibiotic sensitive and multi-resistant Pseudomonas aeruginosa isolates exposed to waste water and tap water.
Sample Metadata Fields
Specimen part
View Samples- Pseudomonas aeruginosa pao1
- 4 Downloadable Samples
Affymetrix Pseudomonas aeruginosa Array (paeg1a)
Description
More than 7% of the Pseudomonas aeruginosa genes are encoding transcriptional regulators, many of which with unknown functions. Among them, those belonging to the LysR family are the most represented. The PA4203 gene lies upstream of the previously characterized ppgL gene (PA4204), which encodes a periplasmic gluconolactonase, which detoxifies gluconolactone by converting it to gluconate. Upstream of PA4203 and in the opposite orientation are the PA4202 gene coding for a nitronate monooxygenase and ddlA (PA4201) encoding a D-alanine alanine ligase. This genetic organization is conserved in all P. aeruginosa genomes, but not in other pseudomonads. The intergenic regions between PA4203 and ppgL, and PA4202 are very short (79 and 107 nucleotides, respectively). PA4203 is a repressor of PA4202 and of its own transcription. A chromatin immunoprecipation analysis confirmed the presence of a single PA4203 binding site between PA4202 and PA4203. Electrophoretic mobility shift assays (EMSAs) with the purified PA4203 protein and in41 gel footprinting with the 1, 10-phenanthroline-copper ion, combined with primer extension analysis to determine transcriptional startpoints allowed the identification of a LysR binding motive in the PA4202 and PA4203 intergenic region. Despite this, a transcriptome analysis revealed more genes to be affected in a PA4203 mutant, likely due to the overexpression of the nitronate monooxygenase (PA4202). Deletion of the PA4202 gene resulted in an increased sensitivity of the cells to 3- nitropropionic acid (3-NPA).
Publication Title
Pseudomonas aeruginosa LysR PA4203 regulator NmoR acts as a repressor of the PA4202 nmoA gene, encoding a nitronate monooxygenase.
Sample Metadata Fields
No sample metadata fields
View Samples- Pseudomonas aeruginosa
- 12 Downloadable Samples
- Affymetrix Pseudomonas aeruginosa Array (paeg1a)
Description
Background Small colony variants (SCVs) are slow-growing bacteria, which often show increased resistance to antibiotics and cause latent or recurrent infections. It is therefore important to understand the mechanisms at the basis of this phenotypic switch. Methodology/Principal findings One SCV (termed PAO-SCV) was isolated, showing high resistance to gentamicin and to the cephalosporine cefotaxime. PAO-SCV was prone to reversion as evidenced by emergence of large colonies with a frequency of 10-5 on media without antibiotics while it was stably maintained in presence of gentamicin. PAO-SCV showed a delayed growth, defective motility, and strongly reduced levels of the quorum sensing Pseudomonas quinolone signal (PQS). Whole genome expression analysis further suggested a multi-layered antibiotic resistance mechanism, including simultaneous over-expression of two drug efflux pumps (MexAB-OprM, MexXY-OprM), the LPS modification operon arnBCADTEF, and the PhoP-PhoQ two-component system. Conversely, the genes for the synthesis of PQS were strongly down-regulated in PAOSCV. Finally, genomic analysis revealed the presence of mutations in phoP and phoQ genes as well as in the mexZ gene encoding a repressor of the mexXY and mexABoprM genes. Only one mutation occurred only in REV, at nucleotide 1020 of the tufA gene, a paralog of tufB, both encoding the elongation factor Tu, causing a change of the rarely used aspartic acid codon GAU to the more common GAC, possibly causing an increase of tufA mRNA translation. High expression of phoP and phoQ was confirmed for the SCV variant while the revertant showed expression levels reduced to wild-type levels. Conclusions By combining data coming from phenotypic, gene expression and proteome analysis, we could demonstrate that resistance to aminoglycosides in one SCV mutant is multifactorial including overexpression of efflux mechanisms, LPS modification and is accompanied by a drastic down-regulation of the Pseudomonas quinolone signal quorum sensing system.
Publication Title
Phenotypic and genome-wide analysis of an antibiotic-resistant small colony variant (SCV) of Pseudomonas aeruginosa.
Sample Metadata Fields
No sample metadata fields
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