Transcriptional regulation of the acetyl-CoA synthetase gene acsA in Pseudomonas aeruginosa

Kretzschmar, U.; Khodaverdi, Viola; Adrian, Lorenz

doi:10.1007/s00203-010-0593-5

Cited by 18 publications

(16 citation statements)

References 24 publications

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“…2-Propanol, an enzyme-mediated product of reduction of acetone, was demonstrated in a breath sample from one patient with CF infected with Pseudomonas aeruginosa 31. We speculate that the elevated EBC ethanol concentrations in patients with CF may be related to the reduced capacity of Pseudomonas aeruginosa to oxidise ethanol to acetate,32 whereas the elevated EBC 2-propanol concentration might be due to bacterial metabolism and/or increased lipolysis and lipid peroxidation 31. Elevated EBC acetate concentrations in healthy subjects could reflect metabolism of oral resident bacteria such as Streptococcus mutans , which degrades pyruvate into end products of metabolism including acetate and lactate 33…”

Section: Discussionmentioning

confidence: 83%

NMR spectroscopy metabolomic profiling of exhaled breath condensate in patients with stable and unstable cystic fibrosis

Montuschi

Paris²,

Melck³

et al. 2011

Thorax

138

129

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Background Metabolomics could provide new insights into the pathophysiology of cystic fibrosis (CF) by identifying profiles of endogenous metabolites. Objectives To investigate whether metabolomics of exhaled breath condensate could discriminate between patients with unstable CF, stable CF and healthy subjects, and whether selected metabolites were responsible for between-group differences. Methods Twenty-nine patients with stable CF, 24 with unstable CF and 31 healthy subjects (age 9e24 years) participated in a cross-sectional study. Metabolomics was performed with high-resolution nuclear magnetic resonance spectroscopy. Partial least squaresdiscriminant analysis was used as classifier. The results were validated in a second independent study. Results Intraclass correlation coefficients for betweenday and technical repeatability were 0.93 and 0.96, respectively. BlandeAltman analysis showed good within-day repeatability. Correct classification rate of CF (n¼53) vs healthy subjects (n¼31) was 96% (R 2 ¼0.84; Q 2 ¼0.79). Model validation with a testing sample set obtained from subjects not included in the primary analysis (23 CF and 25 healthy subjects) showed a sensitivity of 91% and a specificity of 96%. The classification rate of stable CF (n¼29) vs unstable CF patients (n¼24) was 95% (R 2 ¼0.82; Q 2 ¼0.78). Model external validation in 14 patients with stable CF and 16 with unstable CF showed a sensitivity of 86% and a specificity of 94%. Ethanol, acetate, 2-propanol and acetone were most discriminant between patients with CF and healthy subjects, whereas acetate, ethanol, 2-propanol and methanol were the most important metabolites for discriminating between patients with stable and unstable CF. Conclusions Nuclear magnetic resonance spectroscopy of exhaled breath condensate is reproducible, discriminates patients with CF from healthy subjects and patients with unstable CF from those with stable CF, and identifies the metabolites responsible for between-group differences.

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Section: Discussionmentioning

confidence: 83%

NMR spectroscopy metabolomic profiling of exhaled breath condensate in patients with stable and unstable cystic fibrosis

Montuschi

Paris²,

Melck³

et al. 2011

Thorax

138

129

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“…cholerae , V . vulnificus , Pseudomonas , and Shewanella [7,19–21], but the distribution of the CrbS/R genes suggests that they may function in other Gram-negative bacteria as well. However, the nature of the information delivered to the cell as a result of CrbS/R signaling is unknown.…”

Section: Discussionmentioning

confidence: 99%

“…The P . aeruginosa homolog of CrbR, ErdR, is required for regulation of acs and ethanol detoxification [19]. The homolog of CrbR in V .…”

Section: Introductionmentioning

confidence: 99%

Regulation of acetyl-CoA synthetase transcription by the CrbS/R two-component system is conserved in genetically diverse environmental pathogens

et al. 2017

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The CrbS/R two-component signal transduction system is a conserved regulatory mechanism through which specific Gram-negative bacteria control acetate flux into primary metabolic pathways. CrbS/R governs expression of acetyl-CoA synthase (acsA), an enzyme that converts acetate to acetyl-CoA, a metabolite at the nexus of the cell’s most important energy-harvesting and biosynthetic reactions. During infection, bacteria can utilize this system to hijack host acetate metabolism and alter the course of colonization and pathogenesis. In toxigenic strains of Vibrio cholerae, CrbS/R-dependent expression of acsA is required for virulence in an arthropod model. Here, we investigate the function of the CrbS/R system in Pseudomonas aeruginosa, Pseudomonas entomophila, and non-toxigenic V. cholerae strains. We demonstrate that its role in acetate metabolism is conserved; this system regulates expression of the acsA gene and is required for growth on acetate as a sole carbon source. As a first step towards describing the mechanism of signaling through this pathway, we identify residues and domains that may be critical for phosphotransfer. We further demonstrate that although CrbS, the putative hybrid sensor kinase, carries both a histidine kinase domain and a receiver domain, the latter is not required for acsA transcription. In order to determine whether our findings are relevant to pathogenesis, we tested our strains in a Drosophila model of oral infection previously employed for the study of acetate-dependent virulence by V. cholerae. We show that non-toxigenic V. cholerae strains lacking CrbS or CrbR are significantly less virulent than are wild-type strains, while P. aeruginosa and P. entomophila lacking CrbS or CrbR are fully pathogenic. Together, the data suggest that the CrbS/R system plays a central role in acetate metabolism in V. cholerae, P. aeruginosa, and P. entomophila. However, each microbe’s unique environmental adaptations and pathogenesis strategies may dictate conditions under which CrbS/R-mediated acs expression is most critical.

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“…This finding is in agreement with earlier studies suggesting that carrier-mediated transport is not es- ϩ -dependent acetaldehyde dehydrogenase, PA4022 and/or ExaC (PA1984). Acetyl coenzyme A (acetyl-CoA) synthetase (AcsA) is required for acetate utilization in P. aeruginosa (58) and therefore is predicted to be responsible for the activation of acetate into acetyl-CoA during ethanolamine catabolism. The results of the current study suggest that the EBP PA4021 activates transcription of the PA4022-eat-eutBC operon from an RpoN promoter in response to acetaldehyde; a mechanism that is essential for ethanolamine catabolism.…”

Section: Pa4021mentioning

confidence: 99%

Ethanolamine Catabolism in Pseudomonas aeruginosa PAO1 Is Regulated by the Enhancer-Binding Protein EatR (PA4021) and the Alternative Sigma Factor RpoN

et al. 2016

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Although genes encoding enzymes and proteins related to ethanolamine catabolism are widely distributed in the genomes of Pseudomonas spp., ethanolamine catabolism has received little attention among this metabolically versatile group of bacteria. In an attempt to shed light on this subject, this study focused on defining the key regulatory factors that govern the expression of the central ethanolamine catabolic pathway in Pseudomonas aeruginosa PAO1. This pathway is encoded by the PA4022-eateutBC operon and consists of a transport protein (Eat), an ethanolamine-ammonia lyase (EutBC), and an acetaldehyde dehydrogenase (PA4022). EutBC is an essential enzyme in ethanolamine catabolism because it hydrolyzes this amino alcohol into ammonia and acetaldehyde. The acetaldehyde intermediate is then converted into acetate in a reaction catalyzed by acetaldehyde dehydrogenase. Using a combination of growth analyses and ␤-galactosidase fusions, the enhancer-binding protein PA4021 and the sigma factor RpoN were shown to be positive regulators of the PA4022-eat-eutBC operon in P. aeruginosa PAO1. PA4021 and RpoN were required for growth on ethanolamine, and both of these regulatory proteins were essential for induction of the PA4022-eat-eutBC operon. Unexpectedly, the results indicate that acetaldehyde (and not ethanolamine) serves as the inducer molecule that is sensed by PA4021 and leads to the transcriptional activation of the PA4022-eat-eutBC operon. Due to its regulatory role in ethanolamine catabolism, PA4021 was given the name EatR. Both EatR and its target genes are conserved in several other Pseudomonas spp., suggesting that these bacteria share a mechanism for regulating ethanolamine catabolism. IMPORTANCEThe results of this study provide a basis for understanding ethanolamine catabolism and its regulation in Pseudomonas aeruginosa PAO1. Interestingly, expression of the ethanolamine-catabolic genes in this bacterium was found to be under the control of a positive-feedback regulatory loop in a manner dependent on the transcriptional regulator PA4021, the sigma factor RpoN, and the metabolite acetaldehyde. Previously characterized regulators of ethanolamine catabolism are known to sense and respond directly to ethanolamine. In contrast, PA4021 (EatR) appears to monitor the intracellular levels of free acetaldehyde and responds through transcriptional activation of the ethanolamine-catabolic genes. This regulatory mechanism is unique and represents an alternative strategy used by bacteria to govern the acquisition of ethanolamine from their surroundings. E thanolamine serves as a source of carbon and nitrogen for a variety of bacteria, including members of the Enterobacteriaceae, Pseudomonadaceae, and Firmicutes (1-5). From studies mostly centered on Salmonella enterica subsp. enterica serovar Typhimurium and Escherichia coli, there is now a basic understanding of the catabolic steps involved in ethanolamine utilization. Extracellular ethanolamine enters the bacterial cell through simple diffusion or carrier-me...

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Transcriptional regulation of the acetyl-CoA synthetase gene acsA in Pseudomonas aeruginosa

Cited by 18 publications

References 24 publications

NMR spectroscopy metabolomic profiling of exhaled breath condensate in patients with stable and unstable cystic fibrosis

NMR spectroscopy metabolomic profiling of exhaled breath condensate in patients with stable and unstable cystic fibrosis

Regulation of acetyl-CoA synthetase transcription by the CrbS/R two-component system is conserved in genetically diverse environmental pathogens

Ethanolamine Catabolism in Pseudomonas aeruginosa PAO1 Is Regulated by the Enhancer-Binding Protein EatR (PA4021) and the Alternative Sigma Factor RpoN

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