Novel targets of the CbrAB/Crc carbon catabolite control system revealed by transcript abundance in Pseudomonas aeruginosa.
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ABSTRACT:
ORGANISM(S): Pseudomonas aeruginosa PAO1
SUBMITTER: Sylvain Pradervand
PROVIDER: E-GEOD-33245 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:The opportunistic human pathogen Pseudomonas aeruginosa can utilize several carbon and nitrogen compounds as energy sources, which allows the bacterium to grow on a variety of different environments. Nevertheless, the uptake and utilization of these compounds is organized in a hierarchical manner, which is guaranteed by a mechanism named catabolite repression. In P. aeruginosa catabolite repression is a post-transcriptional process with the translational repressor protein, Crc, as the main component. Crc recognizes CA-motifs (acronym for catabolite activity) present in the vicinity of the ribosome binfing site of corresponding target mRNAs and therefore compete with ribosome binding. Certain conditions, which are mainly related to changes in the carbon to nitrogen ratio, induce the two component system CbrAB, which activates the transcription of the sRNA CrcZ. The sRNA sequesters Crc and allows the translation of the target mRNAs. The main focus of this study was to identify novel direct targets of the CbrAB/Crc system with the use of a transcriptome analysis in combination with the search for CA-motifs. We were able to identify five novel targets (estA, acsA, dctP, bkdR and aroP2), which were involved in the uptake and utilization of less preferred carbon sources and amino acids. Direct interaction of Crc with these genes and the resulting regulation by CbrB and CrcZ were verified using mutational analysis and in vitro and in vivo experiments. Moreover, these targets were discussed in the light of growth and biofilm development in synthetic CF sputum medium which emphasised the importance of the CbrAB/Crc system as a regulator of chronic infection. keyword(s): genetic modification Comparative transcriptome analysis with the PAO1 wild type strain and PAO6673 (delta crc), PAO66711 (delta cbrB), PAO6679 (delta crcZ) strains grown in BSM-Succinate medium.
2012-03-31 | E-GEOD-33241 | biostudies-arrayexpress
Project description:The opportunistic human pathogen Pseudomonas aeruginosa can utilize several carbon and nitrogen compounds as energy sources, which allows the bacterium to grow on a variety of different environments. Nevertheless, the uptake and utilization of these compounds is organized in a hierarchical manner, which is guaranteed by a mechanism named catabolite repression. In P. aeruginosa catabolite repression is a post-transcriptional process with the translational repressor protein, Crc, as the main component. Crc recognizes CA-motifs (acronym for catabolite activity) present in the vicinity of the ribosome binfing site of corresponding target mRNAs and therefore compete with ribosome binding. Certain conditions, which are mainly related to changes in the carbon to nitrogen ratio, induce the two component system CbrAB, which activates the transcription of the sRNA CrcZ. The sRNA sequesters Crc and allows the translation of the target mRNAs. The main focus of this study was to identify novel direct targets of the CbrAB/Crc system with the use of a transcriptome analysis in combination with the search for CA-motifs. We were able to identify five novel targets (estA, acsA, dctP, bkdR and aroP2), which were involved in the uptake and utilization of less preferred carbon sources and amino acids. Direct interaction of Crc with these genes and the resulting regulation by CbrB and CrcZ were verified using mutational analysis and in vitro and in vivo experiments. Moreover, these targets were discussed in the light of growth and biofilm development in synthetic CF sputum medium which emphasised the importance of the CbrAB/Crc system as a regulator of chronic infection. Comparative transcriptome analysis with the PAO1 wild type strain and PAO6673 (delta crc), PAO66711 (delta cbrB), PAO6679 (delta crcZ) strains grown in LB medium.
2012-03-31 | E-GEOD-33244 | biostudies-arrayexpress
Project description:Effect of deletion of pppA and ppkA genes in Pseudomonas aeruginosa on global transcriptome of mutant strain and effect of this deletion on response to oxidative stress.
2012-01-01 | E-MEXP-3117 | biostudies-arrayexpress
Project description:Pseudomonas aeruginosa is a virulent opportunistic pathogen responsible for high morbity in COPD, burns , implanted medical devices and cystic fibrosis. Pseudomonas aeruginosa is a problematic colonizer of the human lung. P. aeruginosa produces a phospholipase C (PlcH) that degrades choline-containing lipids such as phosphatidylcholine and sphingomylein that are found in lung surfactant and in host membranes. In this study, we analyzed gene expression in mutants defective in PlcH production (delta-plcH and delta-gbdR) and the wild type when growing in medium with lung surfactant. Pseudomonas aeruginosa was cultured in liquid cultures with aeration in a defined medium with Survanta, a lung surfactant replacement. Cultures were harvested during mid-exponential phase, and RNA was isolated for microarray analysis. The P. aeruginosa strain PAO1 wild type gene expression was compared to expression profiles from delta-gbdR and delta-plcHR deletion mutants, two mutants defective in PlcH production.
2013-01-01 | E-GEOD-41926 | biostudies-arrayexpress
Project description:Quorum sensing, a cell-to-cell communication system based on small signal molecules, is employed by the human pathogen Pseudomonas aeruginosa to regulate virulence and biofilm development. Moreover, regulation by small trans-encoded RNAs has become a focal issue in virulence gene expression of bacterial pathogens. In this study, we have identified the small RNA PhrS as an activator of PqsR synthesis, one of the key quorum sensing regulators in P. aeruginosa. Genetic studies revealed a novel mode of regulation by a sRNA, whereby PhrS uses a base-pairing mechanism to activate a short upstream open reading frame to which the pqsR gene is translationally coupled. Expression of phrS is induced by the oxygen-responsive regulator ANR when the oxygen supply decreases. Thus, PhrS is the first bacterial sRNA that provides a regulatory link between oxygen availability and quorum sensing, which may impact on oxygen-limited growth in P. aeruginosa biofilms. Keywords: genetic modification Comparative transcriptome analysis with the delta-phrS strains PAO6671(pJT19) and PAO6671(pJTphrS), whereby the first strain harboured the parental vector and the latter a plasmid-borne inducible phrS gene
2011-06-27 | E-GEOD-25595 | biostudies-arrayexpress
Project description:A hallmark of the biofilm architecture is the presence of microcolonies. However, little is known about the underlying mechanisms governing microcolony formation. In the human pathogen Pseudomonas aeruginosa, microcolony formation is dependent on the two-component regulator MifR, with mifR mutant biofilms exhibiting an overall thin structure lacking microcolonies, and overexpression of mifR resulting in hyper-microcolony formation. Here, we made use of the distinct MifR-dependent phenotypes to elucidate mechanisms associated with microcolony formation. Using global transcriptomic and proteomic approaches, we demonstrate that cells located within microcolonies experience stressful, oxygen limited, and energy starving conditions, as indicated by the activation of stress response mechanisms and anaerobic and fermentative processes, in particular pyruvate fermentation. Inactivation of genes involved in pyruvate utilization including uspK, acnA and ldhA abrogated microcolony formation in a manner similar to mifR inactivation. Moreover, depletion of pyruvate from the growth medium impaired biofilm and microcolony formation, while addition of pyruvate significantly increased microcolony formation. Addition of pyruvate partly restored microcolony formation in M-bM-^HM-^FmifR biofilms. Moreover, addition of pyruvate to or expression of mifR in lactate dehydrogenase (ldhA) mutant biofilms did not restore microcolony formation. Consistent with the finding of denitrification genes not demonstrating distinct expression patterns in biofilms forming or lacking microcolonies, addition of nitrate did not alter microcolony formation. Our findings indicate the fermentative utilization of pyruvate to be a microcolony-specific adaptation to the oxygen limitation and energy starvation of the P. aeruginosa biofilm environment. For biofilm growth experiments, three independent replicates of P. aeruginosa strains PAO1 and M-NM-^TmifR were grown as biofilms in a flow-through system using a once-through continuous flow tube reactor system for biofilm sample collection and in flow cells (BioSurface Technologies) for the analysis of biofilm architecture as previously described (Sauer et al., 2002, Sauer et al., 2004, Petrova & Sauer, 2009). Cells were treated with RNAprotect (Qiagen) and total RNA was extracted using an RNeasy mini purification kit (Qiagen) per the manufacturerM-bM-^@M-^Ys instructions. RNA quality and the presence of residual DNA were checked on an Agilent Bioanalyzer 2100 electrophoretic system pre- and post-DNase treatment. Ten micrograms of total RNA was used for cDNA synthesis, fragmentation, and labeling according to the Affymetrix GeneChip P. aeruginosa genome array expression analysis protocol. Sauer, K., A. K. Camper, G. D. Ehrlich, J. W. Costerton & D. G. Davies, (2002) Pseudomonas aeruginosa displays multiple phenotypes during development as a biofilm. J. Bacteriol. 184: 1140-1154. Sauer, K., M. C. Cullen, A. H. Rickard, L. A. H. Zeef, D. G. Davies & P. Gilbert, (2004) Characterization of nutrient-induced dispersion in Pseudomonas aeruginosa PAO1 biofilm. J. Bacteriol. 186: 7312-7326. Petrova, O. E. & K. Sauer, (2009) A novel signaling network essential for regulating Pseudomonas aeruginosa biofilm development. PLoS Pathogens 5: e1000668.
2012-04-30 | E-GEOD-35286 | biostudies-arrayexpress
Project description:Pseudomonas aeruginosa is an opportunistic human pathogen, infecting immuno-compromised patients and causing persistent respiratory infections in people affected from cystic fibrosis. Pseudomonas strain Pseudomonas aeruginosa PA14 shows higher virulence than Pseudomonas aeruginosa PAO1 in a wide range of hosts including insects, nematodes and plants but the precise cause of this difference is not fully understood. Little is known about the host response upon infection with Pseudomonas and whether or not transcription is being affected as a host defense mechanism or altered in the benefit of the pathogen. In this context the social amoeba Dictyostelium discoideum has been described as a suitable host to study virulence of Pseudomonas and other opportunistic pathogens.
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Project description:Drastic alterations in transcripts associated with central carbon metabolism and associated processes have been repeatedly observed a common expression program as P. aeruginosa adapts to the cystic fibrosis lung when compared to standard laboratory conditions. However, we have limited knowledge of how well these transcriptomic changes correlate with actual alterations in metabolic flux; the rate of turnover of molecules through metabolic pathways. We have compared the transcriptome of Pseudomonas aeruginosa PAO1 during growth on the carbon sources acetate and glycerol.
2019-10-05 | E-MTAB-8374 | biostudies-arrayexpress
Project description:The opportunistic human pathogen Pseudomonas aeruginosa can utilize several carbon and nitrogen compounds as energy sources, which allows the bacterium to grow on a variety of different environments. Nevertheless, the uptake and utilization of these compounds is organized in a hierarchical manner, which is guaranteed by a mechanism named catabolite repression. In P. aeruginosa catabolite repression is a post-transcriptional process with the translational repressor protein, Crc, as the main component. Crc recognizes CA-motifs (acronym for catabolite activity) present in the vicinity of the ribosome binfing site of corresponding target mRNAs and therefore compete with ribosome binding. Certain conditions, which are mainly related to changes in the carbon to nitrogen ratio, induce the two component system CbrAB, which activates the transcription of the sRNA CrcZ. The sRNA sequesters Crc and allows the translation of the target mRNAs. The main focus of this study was to identify novel direct targets of the CbrAB/Crc system with the use of a transcriptome analysis in combination with the search for CA-motifs. We were able to identify five novel targets (estA, acsA, dctP, bkdR and aroP2), which were involved in the uptake and utilization of less preferred carbon sources and amino acids. Direct interaction of Crc with these genes and the resulting regulation by CbrB and CrcZ were verified using mutational analysis and in vitro and in vivo experiments. Moreover, these targets were discussed in the light of growth and biofilm development in synthetic CF sputum medium which emphasised the importance of the CbrAB/Crc system as a regulator of chronic infection.
2012-04-01 | GSE33244 | GEO
Project description:The opportunistic human pathogen Pseudomonas aeruginosa can utilize several carbon and nitrogen compounds as energy sources, which allows the bacterium to grow on a variety of different environments. Nevertheless, the uptake and utilization of these compounds is organized in a hierarchical manner, which is guaranteed by a mechanism named catabolite repression. In P. aeruginosa catabolite repression is a post-transcriptional process with the translational repressor protein, Crc, as the main component. Crc recognizes CA-motifs (acronym for catabolite activity) present in the vicinity of the ribosome binfing site of corresponding target mRNAs and therefore compete with ribosome binding. Certain conditions, which are mainly related to changes in the carbon to nitrogen ratio, induce the two component system CbrAB, which activates the transcription of the sRNA CrcZ. The sRNA sequesters Crc and allows the translation of the target mRNAs. The main focus of this study was to identify novel direct targets of the CbrAB/Crc system with the use of a transcriptome analysis in combination with the search for CA-motifs. We were able to identify five novel targets (estA, acsA, dctP, bkdR and aroP2), which were involved in the uptake and utilization of less preferred carbon sources and amino acids. Direct interaction of Crc with these genes and the resulting regulation by CbrB and CrcZ were verified using mutational analysis and in vitro and in vivo experiments. Moreover, these targets were discussed in the light of growth and biofilm development in synthetic CF sputum medium which emphasised the importance of the CbrAB/Crc system as a regulator of chronic infection. keyword(s): genetic modification
2012-04-01 | GSE33241 | GEO