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Pedersen BH, Simões FB, Pogrebnyakov I, Welch M, Johansen HK, Molin S, La Rosa R. Metabolic specialization drives reduced pathogenicity in Pseudomonas aeruginosa isolates from cystic fibrosis patients. PLoS Biol 2024; 22:e3002781. [PMID: 39178315 DOI: 10.1371/journal.pbio.3002781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 08/01/2024] [Indexed: 08/25/2024] Open
Abstract
Metabolism provides the foundation for all cellular functions. During persistent infections, in adapted pathogenic bacteria metabolism functions radically differently compared with more naïve strains. Whether this is simply a necessary accommodation to the persistence phenotype or if metabolism plays a direct role in achieving persistence in the host is still unclear. Here, we characterize a convergent shift in metabolic function(s) linked with the persistence phenotype during Pseudomonas aeruginosa colonization in the airways of people with cystic fibrosis. We show that clinically relevant mutations in the key metabolic enzyme, pyruvate dehydrogenase, lead to a host-specialized metabolism together with a lower virulence and immune response recruitment. These changes in infection phenotype are mediated by impaired type III secretion system activity and by secretion of the antioxidant metabolite, pyruvate, respectively. Our results show how metabolic adaptations directly impinge on persistence and pathogenicity in this organism.
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Affiliation(s)
- Bjarke Haldrup Pedersen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Filipa Bica Simões
- Department of Clinical Microbiology 9301, Rigshospitalet, Copenhagen, Denmark
| | - Ivan Pogrebnyakov
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Martin Welch
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Helle Krogh Johansen
- Department of Clinical Microbiology 9301, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Søren Molin
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Ruggero La Rosa
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
- Department of Clinical Microbiology 9301, Rigshospitalet, Copenhagen, Denmark
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Alreshidi M, Dunstan H, Roberts T, Alreshidi F, Hossain A, Bardakci F, Snoussi M, Badraoui R, Adnan M, Alouffi S, Saeed M. Cytoplasmic amino acid profiles of clinical and ATCC 29213 strains of Staphylococcus aureus harvested at different growth phases. BIOMOLECULES & BIOMEDICINE 2023; 23:1038-1050. [PMID: 37270805 PMCID: PMC10655876 DOI: 10.17305/bb.2023.9246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 05/31/2023] [Accepted: 05/31/2023] [Indexed: 06/06/2023]
Abstract
Staphylococcus aureus strains are a great contributor to both hospital acquired infections as well as community acquired infections. The objective of the present investigation was to compare potential differences in cytoplasmic amino acid levels between clinical and ATCC 29213 strains of S. aureus. The two strains were grown under ideal conditions to mid-exponential and stationary growth phases, after which they were harvested to analyze their amino acid profiles. Initially, the amino acid patterns of both strains were compared at the mid-exponential phase when grown in controlled conditions. At the mid-exponential phase, both strains shared common features in cytoplasmic amino acid levels, with glutamic acid, aspartic acid, proline, and alanine identified as key amino acids. However, the concentration profiles of seven amino acids exhibited major variances between the strains, even though the total cytoplasmic levels of amino acids did not alter significantly. At the stationary phase, the magnitudes of the amino acids abundant in the mid-exponential phase were altered. Aspartic acid became the most abundant amino acid in both strains accounting for 44% and 59% of the total amino acids in the clinical and ATCC 29213 strains, respectively. Lysine was the second most abundant amino acid in both strains, accounting for 16% of the total cytoplasmic amino acids, followed by glutamic acid, the concentration of which was significantly higher in the clinical strain than in the ATCC 29213 strain. Interestingly, histidine was clearly present in the clinical strain but was virtually lacking in the ATCC 29213 strain. This study reveals the dynamic diversity of amino acid levels among strains, which is an essential step toward illustrating the variability in S. aureus cytoplasmic amino acid profiles and could be significant in explaining variances among strains of S. aureus.
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Affiliation(s)
- Mousa Alreshidi
- Department of Biology, College of Science, University of Ha’il, Ha’il, Saudi Arabia
| | | | - Tim Roberts
- Metabolic Research Group, Faculty of Science, School of Environmental and Life Sciences, University Drive, Callaghan, NSW, Australia
| | - Fayez Alreshidi
- Department of Family and Community Medicine, College of Medicine, University of Ha’il, Ha’il, Saudi Arabia
| | - Ashfaque Hossain
- Department of Medical Microbiology and Immunology, RAK Medical and Health Sciences University, RAK Hospital, Al Qusaidat, Ras Al Khaimah, United Arab Emirates
| | - Fevzi Bardakci
- Department of Biology, College of Science, University of Ha’il, Ha’il, Saudi Arabia
| | - Mejdi Snoussi
- Department of Biology, College of Science, University of Ha’il, Ha’il, Saudi Arabia
- Laboratory of Genetics, Biodiversity and Valorization of Bio-Resources (LR11ES41), Higher Institute of Biotechnology of Monastir, University of Monastir, Monastir, Tunisia
| | - Riadh Badraoui
- Department of Biology, College of Science, University of Ha’il, Ha’il, Saudi Arabia
| | - Mohd Adnan
- Department of Biology, College of Science, University of Ha’il, Ha’il, Saudi Arabia
| | - Sultan Alouffi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, University of Ha’il, Ha’il, Saudi Arabia
| | - Mohd Saeed
- Department of Biology, College of Science, University of Ha’il, Ha’il, Saudi Arabia
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Genome-scale model of Pseudomonas aeruginosa metabolism unveils virulence and drug potentiation. Commun Biol 2023; 6:165. [PMID: 36765199 PMCID: PMC9918512 DOI: 10.1038/s42003-023-04540-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/30/2023] [Indexed: 02/12/2023] Open
Abstract
Pseudomonas aeruginosa is one of the leading causes of hospital-acquired infections. To decipher the metabolic mechanisms associated with virulence and antibiotic resistance, we have developed an updated genome-scale model (GEM) of P. aeruginosa. The model (iSD1509) is an extensively curated, three-compartment, and mass-and-charge balanced BiGG model containing 1509 genes, the largest gene content for any P. aeruginosa GEM to date. It is the most accurate with prediction accuracies as high as 92.4% (gene essentiality) and 93.5% (substrate utilization). In iSD1509, we newly added a recently discovered pathway for ubiquinone-9 biosynthesis which is required for anaerobic growth. We used a modified iSD1509 to demonstrate the role of virulence factor (phenazines) in the pathogen survival within biofilm/oxygen-limited condition. Further, the model can mechanistically explain the overproduction of a drug susceptibility biomarker in the P. aeruginosa mutants. Finally, we use iSD1509 to demonstrate the drug potentiation by metabolite supplementation, and elucidate the mechanisms behind the phenotype, which agree with experimental results.
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Systems-Wide Dissection of Organic Acid Assimilation in Pseudomonas aeruginosa Reveals a Novel Path To Underground Metabolism. mBio 2022; 13:e0254122. [PMID: 36377867 PMCID: PMC9765439 DOI: 10.1128/mbio.02541-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The human pathogen Pseudomonas aeruginosa (Pa) is one of the most frequent and severe causes of nosocomial infection. This organism is also a major cause of airway infections in people with cystic fibrosis (CF). Pa is known to have a remarkable metabolic plasticity, allowing it to thrive under diverse environmental conditions and ecological niches; yet, little is known about the central metabolic pathways that sustain its growth during infection or precisely how these pathways operate. In this work, we used a combination of 'omics approaches (transcriptomics, proteomics, metabolomics, and 13C-fluxomics) and reverse genetics to provide systems-level insight into how the infection-relevant organic acids succinate and propionate are metabolized by Pa. Moreover, through structural and kinetic analysis of the 2-methylcitrate synthase (2-MCS; PrpC) and its paralogue citrate (CIT) synthase (GltA), we show how these two crucial enzymatic steps are interconnected in Pa organic acid assimilation. We found that Pa can rapidly adapt to the loss of GltA function by acquiring mutations in a transcriptional repressor, which then derepresses prpC expression. Our findings provide a clear example of how "underground metabolism," facilitated by enzyme substrate promiscuity, "rewires" Pa metabolism, allowing it to overcome the loss of a crucial enzyme. This pathogen-specific knowledge is critical for the advancement of a model-driven framework to target bacterial central metabolism. IMPORTANCE Pseudomonas aeruginosa is an opportunistic human pathogen that, due to its unrivalled resistance to antibiotics, ubiquity in the built environment, and aggressiveness in infection scenarios, has acquired the somewhat dubious accolade of being designated a "critical priority pathogen" by the WHO. In this work, we uncover the pathways and mechanisms used by P. aeruginosa to grow on a substrate that is abundant at many infection sites: propionate. We found that if the organism is prevented from metabolizing propionate, the substrate turns from being a convenient nutrient source into a potent poison, preventing bacterial growth. We further show that one of the enzymes involved in these reactions, 2-methylcitrate synthase (PrpC), is promiscuous and can moonlight for another essential enzyme in the cell (citrate synthase). Indeed, mutations that abolish citrate synthase activity (which would normally prevent the cell from growing) can be readily overcome if the cell acquires additional mutations that increase the expression of PrpC. This is a nice example of the evolutionary utility of so-called "underground metabolism."
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Temporal Hierarchy and Context-Dependence of Quorum Sensing Signal in Pseudomonas aeruginosa. LIFE (BASEL, SWITZERLAND) 2022; 12:life12121953. [PMID: 36556318 PMCID: PMC9781131 DOI: 10.3390/life12121953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/15/2022] [Accepted: 11/18/2022] [Indexed: 11/24/2022]
Abstract
The Gram-negative bacterium Pseudomonas aeruginosa can cause infections in a broad range of hosts including plants, invertebrates and mammals and is an important source of nosocomial infections in humans. We were interested in how differences in the bacteria's nutritional environment impact bacterial communication and virulence factor production. We grew P. aeruginosa in 96 different conditions in BIOLOG Gen III plates and assayed quorum sensing (QS) signaling over the course of growth. We also quantified pyocyanin and biofilm production and the impact of sub-inhibitory exposure to tobramycin. We found that while 3-oxo-C12 homoserine lactone remained the dominant QS signal to be produced, timing of PQS production differed between media types. Further, whether cells grew predominantly as biofilms or planktonic cells was highly context dependent. Our data suggest that understanding the impact of the nutritional environment on the bacterium can lead to valuable insights into the link between bacterial physiology and pathology.
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Nolan C, Behrends V. Sub-Inhibitory Antibiotic Exposure and Virulence in Pseudomonas aeruginosa. Antibiotics (Basel) 2021; 10:antibiotics10111393. [PMID: 34827331 PMCID: PMC8615142 DOI: 10.3390/antibiotics10111393] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 12/20/2022] Open
Abstract
Pseudomonas aeruginosa is a prime opportunistic pathogen, one of the most important causes of hospital-acquired infections and the major cause of morbidity and mortality in cystic fibrosis lung infections. One reason for the bacterium's pathogenic success is the large array of virulence factors that it can employ. Another is its high degree of intrinsic and acquired resistance to antibiotics. In this review, we first summarise the current knowledge about the regulation of virulence factor expression and production. We then look at the impact of sub-MIC antibiotic exposure and find that the virulence-antibiotic interaction for P. aeruginosa is antibiotic-specific, multifaceted, and complex. Most studies undertaken to date have been in vitro assays in batch culture systems, involving short-term (<24 h) antibiotic exposure. Therefore, we discuss the importance of long-term, in vivo-mimicking models for future work, particularly highlighting the need to account for bacterial physiology, which by extension governs both virulence factor expression and antibiotic tolerance/resistance.
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Moyne O, Castelli F, Bicout DJ, Boccard J, Camara B, Cournoyer B, Faudry E, Terrier S, Hannani D, Huot-Marchand S, Léger C, Maurin M, Ngo TD, Plazy C, Quinn RA, Attree I, Fenaille F, Toussaint B, Le Gouëllec A. Metabotypes of Pseudomonas aeruginosa Correlate with Antibiotic Resistance, Virulence and Clinical Outcome in Cystic Fibrosis Chronic Infections. Metabolites 2021; 11:metabo11020063. [PMID: 33494144 PMCID: PMC7909822 DOI: 10.3390/metabo11020063] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 02/07/2023] Open
Abstract
Pseudomonas aeruginosa (P.a) is one of the most critical antibiotic resistant bacteria in the world and is the most prevalent pathogen in cystic fibrosis (CF), causing chronic lung infections that are considered one of the major causes of mortality in CF patients. Although several studies have contributed to understanding P.a within-host adaptive evolution at a genomic level, it is still difficult to establish direct relationships between the observed mutations, expression of clinically relevant phenotypes, and clinical outcomes. Here, we performed a comparative untargeted LC/HRMS-based metabolomics analysis of sequential isolates from chronically infected CF patients to obtain a functional view of P.a adaptation. Metabolic profiles were integrated with expression of bacterial phenotypes and clinical measurements following multiscale analysis methods. Our results highlighted significant associations between P.a “metabotypes”, expression of antibiotic resistance and virulence phenotypes, and frequency of clinical exacerbations, thus identifying promising biomarkers and therapeutic targets for difficult-to-treat P.a infections
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Affiliation(s)
- Oriane Moyne
- Département de Biochimie, Faculté de médecine de Grenoble, CNRS, CHU Grenoble Alpes, University Grenoble Alpes, Grenoble INP*, TIMC-IMAG, 38000 Grenoble, France; (O.M.); (D.J.B.); (D.H.); (S.H.-M.); (C.L.); (M.M.); (C.P.); (B.T.)
| | - Florence Castelli
- Département Médicaments et Technologies pour la Santé (DMTS), University Paris-Saclay, CEA, INRAE, MetaboHUB, 91191 Gif sur Yvette, France; (F.C.); (S.T.); (F.F.)
| | - Dominique J. Bicout
- Département de Biochimie, Faculté de médecine de Grenoble, CNRS, CHU Grenoble Alpes, University Grenoble Alpes, Grenoble INP*, TIMC-IMAG, 38000 Grenoble, France; (O.M.); (D.J.B.); (D.H.); (S.H.-M.); (C.L.); (M.M.); (C.P.); (B.T.)
- Biomathematics and Epidemiology EPSP-TIMC, Veterinary Campus of Lyon, VetAgro Sup, 69280 Marcy l’Etoile, France
- Laue-Langevin Institute, Theory Group, 71 Avenue des Martyrs, 38042 Grenoble, France
| | - Julien Boccard
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, 1211 Geneva, Switzerland;
| | - Boubou Camara
- CHU Grenoble Alpes, Service Hospitalier Universitaire de Pneumologie, Centre de Compétence de la Mucoviscidose, 38000 Grenoble, France;
| | - Benoit Cournoyer
- Department of Veterinary and biological sciences, Université Claude Bernard Lyon 1, University Lyon 1, VetAgro Sup, UMR Ecologie Microbienne, CNRS 5557, INRA 1418, 69280 Marcy L’Etoile, France;
| | - Eric Faudry
- CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, University Grenoble Alpes, UMR 1036/ERL 5261, 17 avenue des Martyrs, 38054 Grenoble, France; (E.F.); (T.-D.N.); (I.A.)
| | - Samuel Terrier
- Département Médicaments et Technologies pour la Santé (DMTS), University Paris-Saclay, CEA, INRAE, MetaboHUB, 91191 Gif sur Yvette, France; (F.C.); (S.T.); (F.F.)
| | - Dalil Hannani
- Département de Biochimie, Faculté de médecine de Grenoble, CNRS, CHU Grenoble Alpes, University Grenoble Alpes, Grenoble INP*, TIMC-IMAG, 38000 Grenoble, France; (O.M.); (D.J.B.); (D.H.); (S.H.-M.); (C.L.); (M.M.); (C.P.); (B.T.)
| | - Sarah Huot-Marchand
- Département de Biochimie, Faculté de médecine de Grenoble, CNRS, CHU Grenoble Alpes, University Grenoble Alpes, Grenoble INP*, TIMC-IMAG, 38000 Grenoble, France; (O.M.); (D.J.B.); (D.H.); (S.H.-M.); (C.L.); (M.M.); (C.P.); (B.T.)
| | - Claire Léger
- Département de Biochimie, Faculté de médecine de Grenoble, CNRS, CHU Grenoble Alpes, University Grenoble Alpes, Grenoble INP*, TIMC-IMAG, 38000 Grenoble, France; (O.M.); (D.J.B.); (D.H.); (S.H.-M.); (C.L.); (M.M.); (C.P.); (B.T.)
| | - Max Maurin
- Département de Biochimie, Faculté de médecine de Grenoble, CNRS, CHU Grenoble Alpes, University Grenoble Alpes, Grenoble INP*, TIMC-IMAG, 38000 Grenoble, France; (O.M.); (D.J.B.); (D.H.); (S.H.-M.); (C.L.); (M.M.); (C.P.); (B.T.)
| | - Tuan-Dung Ngo
- CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, University Grenoble Alpes, UMR 1036/ERL 5261, 17 avenue des Martyrs, 38054 Grenoble, France; (E.F.); (T.-D.N.); (I.A.)
| | - Caroline Plazy
- Département de Biochimie, Faculté de médecine de Grenoble, CNRS, CHU Grenoble Alpes, University Grenoble Alpes, Grenoble INP*, TIMC-IMAG, 38000 Grenoble, France; (O.M.); (D.J.B.); (D.H.); (S.H.-M.); (C.L.); (M.M.); (C.P.); (B.T.)
| | - Robert A. Quinn
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA;
| | - Ina Attree
- CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, University Grenoble Alpes, UMR 1036/ERL 5261, 17 avenue des Martyrs, 38054 Grenoble, France; (E.F.); (T.-D.N.); (I.A.)
| | - François Fenaille
- Département Médicaments et Technologies pour la Santé (DMTS), University Paris-Saclay, CEA, INRAE, MetaboHUB, 91191 Gif sur Yvette, France; (F.C.); (S.T.); (F.F.)
| | - Bertrand Toussaint
- Département de Biochimie, Faculté de médecine de Grenoble, CNRS, CHU Grenoble Alpes, University Grenoble Alpes, Grenoble INP*, TIMC-IMAG, 38000 Grenoble, France; (O.M.); (D.J.B.); (D.H.); (S.H.-M.); (C.L.); (M.M.); (C.P.); (B.T.)
| | - Audrey Le Gouëllec
- Département de Biochimie, Faculté de médecine de Grenoble, CNRS, CHU Grenoble Alpes, University Grenoble Alpes, Grenoble INP*, TIMC-IMAG, 38000 Grenoble, France; (O.M.); (D.J.B.); (D.H.); (S.H.-M.); (C.L.); (M.M.); (C.P.); (B.T.)
- Correspondence:
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Potentiation of Aminoglycoside Lethality by C 4-Dicarboxylates Requires RpoN in Antibiotic-Tolerant Pseudomonas aeruginosa. Antimicrob Agents Chemother 2019; 63:AAC.01313-19. [PMID: 31383655 DOI: 10.1128/aac.01313-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 07/29/2019] [Indexed: 01/26/2023] Open
Abstract
Antibiotic tolerance contributes to the inability of standard antimicrobial therapies to clear the chronic Pseudomonas aeruginosa lung infections that often afflict patients with cystic fibrosis (CF). Metabolic potentiation of bactericidal antibiotics with carbon sources has emerged as a promising strategy to resensitize tolerant bacteria to antibiotic killing. Fumarate (FUM), a C4-dicarboxylate, has been recently shown to resensitize tolerant P. aeruginosa to killing by tobramycin (TOB), an aminoglycoside antibiotic, when used in combination (TOB+FUM). Fumarate and other C4-dicarboxylates are taken up intracellularly by transporters regulated by the alternative sigma factor RpoN. Once in the cell, FUM is metabolized, leading to enhanced electron transport chain activity, regeneration of the proton motive force, and increased TOB uptake. In this work, we demonstrate that a ΔrpoN mutant displays impaired FUM uptake and, consequently, nonsusceptibility to TOB+FUM treatment. RpoN was also found to be essential for susceptibility to other aminoglycoside and C4-dicarboxylate combinations. Importantly, RpoN loss-of-function mutations have been documented to evolve in the CF lung, and these loss-of-function alleles can also result in TOB+FUM nonsusceptibility. In a mixed-genotype population of wild-type and ΔrpoN cells, TOB+FUM specifically killed cells with RpoN function and spared the cells that lacked RpoN function. Unlike C4-dicarboylates, both d-glucose and l-arginine were able to potentiate TOB killing of ΔrpoN stationary-phase cells. Our findings raise the question of whether TOB+FUM will be a suitable treatment option in the future for CF patients infected with P. aeruginosa isolates that lack RpoN function.
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9
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Sismaet HJ, Goluch ED. Electrochemical Probes of Microbial Community Behavior. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2018; 11:441-461. [PMID: 29490192 DOI: 10.1146/annurev-anchem-061417-125627] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Advances in next-generation sequencing technology along with decreasing costs now allow the microbial population, or microbiome, of a location to be determined relatively quickly. This research reveals that microbial communities are more diverse and complex than ever imagined. New and specialized instrumentation is required to investigate, with high spatial and temporal resolution, the dynamic biochemical environment that is created by microbes, which allows them to exist in every corner of the Earth. This review describes how electrochemical probes and techniques are being used and optimized to learn about microbial communities. Described approaches include voltammetry, electrochemical impedance spectroscopy, scanning electrochemical microscopy, separation techniques coupled with electrochemical detection, and arrays of complementary metal-oxide-semiconductor circuits. Microbial communities also interact with and influence their surroundings; therefore, the review also includes a discussion of how electrochemical probes optimized for microbial analysis are utilized in healthcare diagnostics and environmental monitoring applications.
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Affiliation(s)
- Hunter J Sismaet
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, USA;
| | - Edgar D Goluch
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, USA;
- Department of Bioengineering, Department of Biology, and Department of Civil and Environmental Engineering, Northeastern University, Boston, Massachusetts 02115, USA
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10
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Abstract
Evolution by natural selection under complex and dynamic environmental conditions occurs through intricate and often counterintuitive trajectories affecting many genes and metabolic solutions. To study short- and long-term evolution of bacteria in vivo, we used the natural model system of cystic fibrosis (CF) infection. In this work, we investigated how and through which trajectories evolution of Pseudomonas aeruginosa occurs when migrating from the environment to the airways of CF patients, and specifically, we determined reduction of growth rate and metabolic specialization as signatures of adaptive evolution. We show that central metabolic pathways of three distinct Pseudomonas aeruginosa lineages coevolving within the same environment become restructured at the cost of versatility during long-term colonization. Cell physiology changes from naive to adapted phenotypes resulted in (i) alteration of growth potential that particularly converged to a slow-growth phenotype, (ii) alteration of nutritional requirements due to auxotrophy, (iii) tailored preference for carbon source assimilation from CF sputum, (iv) reduced arginine and pyruvate fermentation processes, and (v) increased oxygen requirements. Interestingly, although convergence was evidenced at the phenotypic level of metabolic specialization, comparative genomics disclosed diverse mutational patterns underlying the different evolutionary trajectories. Therefore, distinct combinations of genetic and regulatory changes converge to common metabolic adaptive trajectories leading to within-host metabolic specialization. This study gives new insight into bacterial metabolic evolution during long-term colonization of a new environmental niche. Only a few examples of real-time evolutionary investigations in environments outside the laboratory are described in the scientific literature. Remembering that biological evolution, as it has progressed in nature, has not taken place in test tubes, it is not surprising that conclusions from our investigations of bacterial evolution in the CF model system are different from what has been concluded from laboratory experiments. The analysis presented here of the metabolic and regulatory driving forces leading to successful adaptation to a new environment provides an important insight into the role of metabolism and its regulatory mechanisms for successful adaptation of microorganisms in dynamic and complex environments. Understanding the trajectories of adaptation, as well as the mechanisms behind slow growth and rewiring of regulatory and metabolic networks, is a key element to understand the adaptive robustness and evolvability of bacteria in the process of increasing their in vivo fitness when conquering new territories.
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Riquelme SA, Ahn D, Prince A. Pseudomonas aeruginosa and Klebsiella pneumoniae Adaptation to Innate Immune Clearance Mechanisms in the Lung. J Innate Immun 2018; 10:442-454. [PMID: 29617698 PMCID: PMC6785651 DOI: 10.1159/000487515] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 02/08/2018] [Accepted: 02/08/2018] [Indexed: 01/02/2023] Open
Abstract
Many different species of gram-negative bacteria are associated with infection in the lung, causing exacerbations of chronic obstructive pulmonary disease, cystic fibrosis (CF), and ventilator-associated pneumonias. These airway pathogens must adapt to common host clearance mechanisms that include killing by antimicrobial peptides, antibiotics, oxidative stress, and phagocytosis by leukocytes. Bacterial adaptation to the host is often evident phenotypically, with increased extracellular polysaccharide production characteristic of some biofilm-associated organisms. Given the relatively limited repertoire of bacterial strategies to elude airway defenses, it seems likely that organisms sharing the same ecological niche might also share common strategies to persistently infect the lung. In this review, we will highlight some of the major factors responsible for the adaptation of Pseudomonas aeruginosa to the lung, addressing how growth in biofilms enables persistent infection, relevant to, but not limited to, the pathogenesis of infection in CF. In contrast, we will discuss how carbapenem-resistant Klebsiella pneumoniae evade immune clearance, an organism often associated with ventilator-associated pneumonia and health-care-acquired pneumonias, but not a typical pathogen in CF.
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Affiliation(s)
| | | | - Alice Prince
- Department of Pediatrics, Columbia University Medical Center, New York, New York, USA
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12
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Zeden MS, Schuster CF, Bowman L, Zhong Q, Williams HD, Gründling A. Cyclic di-adenosine monophosphate (c-di-AMP) is required for osmotic regulation in Staphylococcus aureus but dispensable for viability in anaerobic conditions. J Biol Chem 2018; 293:3180-3200. [PMID: 29326168 PMCID: PMC5836111 DOI: 10.1074/jbc.m117.818716] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 01/03/2018] [Indexed: 01/15/2023] Open
Abstract
Cyclic di-adenosine monophosphate (c-di-AMP) is a recently discovered signaling molecule important for the survival of Firmicutes, a large bacterial group that includes notable pathogens such as Staphylococcus aureus However, the exact role of this molecule has not been identified. dacA, the S. aureus gene encoding the diadenylate cyclase enzyme required for c-di-AMP production, cannot be deleted when bacterial cells are grown in rich medium, indicating that c-di-AMP is required for growth in this condition. Here, we report that an S. aureus dacA mutant can be generated in chemically defined medium. Consistent with previous findings, this mutant had a severe growth defect when cultured in rich medium. Using this growth defect in rich medium, we selected for suppressor strains with improved growth to identify c-di-AMP-requiring pathways. Mutations bypassing the essentiality of dacA were identified in alsT and opuD, encoding a predicted amino acid and osmolyte transporter, the latter of which we show here to be the main glycine betaine-uptake system in S. aureus. Inactivation of these transporters likely prevents the excessive osmolyte and amino acid accumulation in the cell, providing further evidence for a key role of c-di-AMP in osmotic regulation. Suppressor mutations were also obtained in hepS, hemB, ctaA, and qoxB, coding proteins required for respiration. Furthermore, we show that dacA is dispensable for growth in anaerobic conditions. Together, these findings reveal an essential role for the c-di-AMP signaling network in aerobic, but not anaerobic, respiration in S. aureus.
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Affiliation(s)
- Merve S Zeden
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
| | - Christopher F Schuster
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
| | - Lisa Bowman
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
| | - Qiyun Zhong
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
| | - Huw D Williams
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Angelika Gründling
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
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13
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Röhnisch HE, Eriksson J, Müllner E, Agback P, Sandström C, Moazzami AA. AQuA: An Automated Quantification Algorithm for High-Throughput NMR-Based Metabolomics and Its Application in Human Plasma. Anal Chem 2018; 90:2095-2102. [PMID: 29260864 DOI: 10.1021/acs.analchem.7b04324] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A key limiting step for high-throughput NMR-based metabolomics is the lack of rapid and accurate tools for absolute quantification of many metabolites. We developed, implemented, and evaluated an algorithm, AQuA (Automated Quantification Algorithm), for targeted metabolite quantification from complex 1H NMR spectra. AQuA operates based on spectral data extracted from a library consisting of one standard calibration spectrum for each metabolite. It uses one preselected NMR signal per metabolite for determining absolute concentrations and does so by effectively accounting for interferences caused by other metabolites. AQuA was implemented and evaluated using experimental NMR spectra from human plasma. The accuracy of AQuA was tested and confirmed in comparison with a manual spectral fitting approach using the ChenomX software, in which 61 out of 67 metabolites quantified in 30 human plasma spectra showed a goodness-of-fit (r2) close to or exceeding 0.9 between the two approaches. In addition, three quality indicators generated by AQuA, namely, occurrence, interference, and positional deviation, were studied. These quality indicators permit evaluation of the results each time the algorithm is operated. The efficiency was tested and confirmed by implementing AQuA for quantification of 67 metabolites in a large data set comprising 1342 experimental spectra from human plasma, in which the whole computation took less than 1 s.
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Affiliation(s)
- Hanna E Röhnisch
- Department of Molecular Sciences, Swedish University of Agricultural Sciences , Uppsala, Sweden 75651
| | - Jan Eriksson
- Department of Molecular Sciences, Swedish University of Agricultural Sciences , Uppsala, Sweden 75651
| | - Elisabeth Müllner
- Department of Molecular Sciences, Swedish University of Agricultural Sciences , Uppsala, Sweden 75651
| | - Peter Agback
- Department of Molecular Sciences, Swedish University of Agricultural Sciences , Uppsala, Sweden 75651
| | - Corine Sandström
- Department of Molecular Sciences, Swedish University of Agricultural Sciences , Uppsala, Sweden 75651
| | - Ali A Moazzami
- Department of Molecular Sciences, Swedish University of Agricultural Sciences , Uppsala, Sweden 75651
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14
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Urinary metabolomic analysis to identify preterm neonates exposed to histological chorioamnionitis: A pilot study. PLoS One 2017; 12:e0189120. [PMID: 29211784 PMCID: PMC5718427 DOI: 10.1371/journal.pone.0189120] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 11/20/2017] [Indexed: 01/20/2023] Open
Abstract
OBJECTIVE Chorioamnionitis is a leading cause of preterm birth worldwide, with higher incidence at lower gestational ages. An early and reliable diagnosis of histological chorioamnionitis (HCA) in preterm infants may be helpful in guiding postnatal management, especially the administration of prophylactic antibiotics to prevent early-onset sepsis. The main aim of this study was to investigate metabolomic analysis of urines collected in the first 24 hours of life as diagnostic tool of HCA. METHODS Gestational age-, birth weight-, delivery mode- and sex- matched (1:2) preterm neonates (< 35 weeks' gestation) born to mothers with or without HCA were enrolled from an observational study. Gas chromatography-mass spectrometry (GC-MS)-based metabolomic analysis was performed on urine samples non-invasively collected in the first 24 hours of life. Univariate analysis, partial least square discriminant analysis (PLS-DA) and its associated variable importance in projection (VIP) score were performed. The most affected metabolic pathways were examined by Metabolite Sets Enrichment Analysis (MSEA). RESULTS Fifteen cases (mean GA 30.2 ± 3.8 weeks, mean BW 1415 ± 471.9 grams) and 30 controls (mean GA 30.2 ± 2.9 weeks, mean BW 1426 ± 569.8 grams) were enrolled. Following univariate analysis, 29 metabolites had a significantly different concentration between cases and controls. The supervised PLS-DA model confirmed a separation between the two groups. Only gluconic acid, an oxidation product of glucose, was higher in cases than in controls. All other VIP metabolites were more abundant in the control group. Glutamate metabolism, mitochondrial electron transport chain, citric acid cycle, galactose metabolism, and fructose and mannose degradation metabolism were the most significantly altered pathways (P < 0.01). CONCLUSIONS For the first time, urinary metabolomics was able to discriminate neonates born to mothers with and without HCA. The identification of specifically altered metabolic pathways may be helpful in understanding metabolic derangement following chorioamnionitis.
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15
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Depke T, Franke R, Brönstrup M. Clustering of MS2 spectra using unsupervised methods to aid the identification of secondary metabolites from Pseudomonas aeruginosa. J Chromatogr B Analyt Technol Biomed Life Sci 2017. [DOI: 10.1016/j.jchromb.2017.06.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Zhang C, Wang Z, Zhang D, Zhou J, Lu C, Su X, Ding D. Proteomics and 1H NMR-based metabolomics analysis of pathogenic Vibrio vulnificus aquacultures isolated from sewage drains. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:23704-23713. [PMID: 28864971 DOI: 10.1007/s11356-017-0007-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 08/22/2017] [Indexed: 06/07/2023]
Abstract
Vibrio bacteria live in both marine and freshwater habitats and are associated with aquatic animals. Vibrio vulnificus is a pathogenic bacterium that infects people and livestock. It is usually found in offshore waters or within fish and shellfish. This study presents a comparative proteomic analysis of the outer membrane protein (OMP) changes in V. vulnificus proteins after stimulation with sewage from sewage drains. Using two-dimensional electrophoresis followed by MALDI-TOF MS/MS, 32 protein spots with significant differences in abundance were identified and characterized. These identified proteins were found to be involved in various functional categories, including catalysis, transport, membrane proteins progresses, receptor activity, energy metabolism, cytokine activity, and protein metabolism. The mRNA expression levels of 12 differential proteins were further assessed by qRT-PCR. Seven genes including carboxypeptidase, hemoglobin receptor, succinate dehydrogenase iron-sulfur subunit, ATP synthase subunit alpha, thioredoxin, succinyl-CoA synthetase subunit, and alanine dehydrogenase were downregulated upon stimulation, whereas the protein expression levels HupA receptor, type I secretion outer membrane protein, glutamine synthetase, superoxide dismutase, OmpU, and VuuA were upregulated. 1H NMR spectra showed 18 dysregulated metabolites from V. vulnificus after the sewage stimulation and the pathogenicity was enhanced after that.
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Affiliation(s)
- Chundan Zhang
- School of Marine Science, Ningbo University, Ningbo, China
| | - Zhonghua Wang
- School of Marine Science, Ningbo University, Ningbo, China
| | - Dijun Zhang
- School of Marine Science, Ningbo University, Ningbo, China
| | - Jun Zhou
- School of Marine Science, Ningbo University, Ningbo, China
| | - Chenyang Lu
- School of Marine Science, Ningbo University, Ningbo, China
| | - Xiurong Su
- School of Marine Science, Ningbo University, Ningbo, China.
| | - Dewen Ding
- School of Marine Science, Ningbo University, Ningbo, China.
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17
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Abstract
The versatile and ubiquitous
Pseudomonas aeruginosa is an opportunistic pathogen causing acute and chronic infections in predisposed human subjects. Here we review recent progress in understanding
P. aeruginosa population biology and virulence, its cyclic di-GMP-mediated switches of lifestyle, and its interaction with the mammalian host as well as the role of the type III and type VI secretion systems in
P. aeruginosa infection.
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Affiliation(s)
- Jens Klockgether
- Molecular Pathology of Cystic Fibrosis Clinical Research Group, Clinic for Paediatric Pneumology, Allergology, and Neonatology, OE 6710, Hannover Medical School, Hannover, Germany
| | - Burkhard Tümmler
- Molecular Pathology of Cystic Fibrosis Clinical Research Group, Clinic for Paediatric Pneumology, Allergology, and Neonatology, OE 6710, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hannover, Germany
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18
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Kostidis S, Addie RD, Morreau H, Mayboroda OA, Giera M. Quantitative NMR analysis of intra- and extracellular metabolism of mammalian cells: A tutorial. Anal Chim Acta 2017. [PMID: 28622799 DOI: 10.1016/j.aca.2017.05.011] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Metabolomics analysis of body fluids as well as cells is depended on many factors. While several well-accepted standard operating procedures for the analysis of body fluids are available, the NMR based quantitative analysis of cellular metabolites is less well standardized. Experimental designs depend on the cell type, the quenching protocol and the applied post-acquisition workflow. Here, we provide a tutorial for the quantitative description of the metabolic phenotype of mammalian cells using NMR spectroscopy. We discuss all key steps of the process, starting from the selection of the appropriate culture medium, quenching techniques to arrest metabolism in a reproducible manner, the extraction of the intracellular components and the profiling of the culture medium. NMR data acquisition and methods for both qualitative and quantitative analysis are also provided. The suggested methods cover experiments for adherent cells and cells in suspension. We ultimately describe the application of the discussed workflow to a thyroid cancer cell line. Although this tutorial focuses on mammalian cells, the given guidelines and procedures may be adjusted for the analysis of other cell types.
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Affiliation(s)
- Sarantos Kostidis
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, 2300RC, Leiden, The Netherlands.
| | - Ruben D Addie
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, 2300RC, Leiden, The Netherlands; Department of Pathology, Leiden University Medical Center, Albinusdreef 2, 2300RC, Leiden, The Netherlands
| | - Hans Morreau
- Department of Pathology, Leiden University Medical Center, Albinusdreef 2, 2300RC, Leiden, The Netherlands
| | - Oleg A Mayboroda
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, 2300RC, Leiden, The Netherlands
| | - Martin Giera
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, 2300RC, Leiden, The Netherlands
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19
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Yan D, Afifi L, Jeon C, Trivedi M, Chang HW, Lee K, Liao W. The metabolomics of psoriatic disease. PSORIASIS (AUCKLAND, N.Z.) 2017; 7:1-15. [PMID: 28824870 PMCID: PMC5562362 DOI: 10.2147/ptt.s118348] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Metabolomics is an emerging new "omics" field involving the systematic analysis of the metabolites in a biologic system. These metabolites provide a molecular snapshot of cellular activity and are thus important for understanding the functional changes in metabolic pathways that drive disease. Recently, metabolomics has been used to study the local and systemic metabolic changes in psoriasis and its cardiometabolic comorbidities. Such studies have revealed novel insights into disease pathogenesis and suggest new biochemical signatures that may be used as a marker of psoriatic disease. This review will discuss common strategies in metabolomics analysis, current findings in the metabolomics of psoriasis, and emerging trends in psoriatic metabolomics.
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Affiliation(s)
- Di Yan
- Department of Dermatology, University of California-San Francisco, San Francisco, CA, USA
| | - Ladan Afifi
- Department of Dermatology, University of California-San Francisco, San Francisco, CA, USA
| | - Caleb Jeon
- Department of Dermatology, University of California-San Francisco, San Francisco, CA, USA
| | - Megha Trivedi
- Department of Dermatology, University of California-San Francisco, San Francisco, CA, USA
| | - Hsin Wen Chang
- Department of Dermatology, University of California-San Francisco, San Francisco, CA, USA
| | - Kristina Lee
- Department of Dermatology, University of California-San Francisco, San Francisco, CA, USA
| | - Wilson Liao
- Department of Dermatology, University of California-San Francisco, San Francisco, CA, USA
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20
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O'Leary BM, Neale HC, Geilfus CM, Jackson RW, Arnold DL, Preston GM. Early changes in apoplast composition associated with defence and disease in interactions between Phaseolus vulgaris and the halo blight pathogen Pseudomonas syringae Pv. phaseolicola. PLANT, CELL & ENVIRONMENT 2016; 39:2172-84. [PMID: 27239727 PMCID: PMC5026161 DOI: 10.1111/pce.12770] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 05/23/2016] [Indexed: 05/19/2023]
Abstract
The apoplast is the arena in which endophytic pathogens such as Pseudomonas syringae grow and interact with plant cells. Using metabolomic and ion analysis techniques, this study shows how the composition of Phaseolus vulgaris leaf apoplastic fluid changes during the first six hours of compatible and incompatible interactions with two strains of P. syringae pv. phaseolicola (Pph) that differ in the presence of the genomic island PPHGI-1. Leaf inoculation with the avirulent island-carrying strain Pph 1302A elicited effector-triggered immunity (ETI) and resulted in specific changes in apoplast composition, including increases in conductivity, pH, citrate, γ-aminobutyrate (GABA) and K(+) , that are linked to the onset of plant defence responses. Other apoplastic changes, including increases in Ca(2+) , Fe(2/3+) Mg(2+) , sucrose, β-cyanoalanine and several amino acids, occurred to a relatively similar extent in interactions with both Pph 1302A and the virulent, island-less strain Pph RJ3. Metabolic footprinting experiments established that Pph preferentially metabolizes malate, glucose and glutamate, but excludes certain other abundant apoplastic metabolites, including citrate and GABA, until preferred metabolites are depleted. These results demonstrate that Pph is well-adapted to the leaf apoplast metabolic environment and that loss of PPHGI-1 enables Pph to avoid changes in apoplast composition linked to plant defences.
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Affiliation(s)
- Brendan M O'Leary
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth, 6009, Australia
| | - Helen C Neale
- Faculty of Health and Applied Sciences, University of the West of England, Bristol, BS16 1QY, United Kingdom
| | - Christoph-Martin Geilfus
- Faculty of Agricultural and Nutritional Sciences, Institute of Plant Nutrition and Soil Science, Kiel University, Kiel, 24118, Germany
| | - Robert W Jackson
- School of Biological Sciences, University of Reading, Reading, RG6 6AH, UK
| | - Dawn L Arnold
- Faculty of Health and Applied Sciences, University of the West of England, Bristol, BS16 1QY, United Kingdom
| | - Gail M Preston
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK.
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RpoN Modulates Carbapenem Tolerance in Pseudomonas aeruginosa through Pseudomonas Quinolone Signal and PqsE. Antimicrob Agents Chemother 2016; 60:5752-64. [PMID: 27431228 DOI: 10.1128/aac.00260-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 07/05/2016] [Indexed: 01/09/2023] Open
Abstract
The ability of Pseudomonas aeruginosa to rapidly modulate its response to antibiotic stress and persist in the presence of antibiotics is closely associated with the process of cell-to-cell signaling. The alternative sigma factor RpoN (σ(54)) is involved in the regulation of quorum sensing (QS) and plays an important role in the survival of stationary-phase cells in the presence of carbapenems. Here, we demonstrate that a ΔrpoN mutant grown in nutrient-rich medium has increased expression of pqsA, pqsH, and pqsR throughout growth, resulting in the increased production of the Pseudomonas quinolone signal (PQS). The link between pqsA and its role in carbapenem tolerance was studied using a ΔrpoN ΔpqsA mutant, in which the carbapenem-tolerant phenotype of the ΔrpoN mutant was abolished. In addition, we demonstrate that another mechanism leading to carbapenem tolerance in the ΔrpoN mutant is mediated through pqsE Exogenously supplied PQS abolished the biapenem-sensitive phenotype of the ΔrpoN ΔpqsA mutant, and overexpression of pqsE failed to alter the susceptibility of the ΔrpoN ΔpqsA mutant to biapenem. The mutations in the ΔrpoN ΔrhlR mutant and the ΔrpoN ΔpqsH mutant led to susceptibility to biapenem. Comparison of the changes in the expression of the genes involved in QS in wild-type PAO1 with their expression in the ΔrpoN mutant and the ΔrpoN mutant-derived strains demonstrated the regulatory effect of RpoN on the transcript levels of rhlR, vqsR, and rpoS The findings of this study demonstrate that RpoN negatively regulates the expression of PQS in nutrient-rich medium and provide evidence that RpoN interacts with pqsA, pqsE, pqsH, and rhlR in response to antibiotic stress.
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22
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Dessì A, Pintus R, Marras S, Cesare Marincola F, De Magistris A, Fanos V. Metabolomics in necrotizing enterocolitis: the state of the art. Expert Rev Mol Diagn 2016; 16:1053-1058. [DOI: 10.1080/14737159.2016.1211933] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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23
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Gierok P, Kohler C, Steinmetz I, Lalk M. Burkholderia pseudomallei Colony Morphotypes Show a Synchronized Metabolic Pattern after Acute Infection. PLoS Negl Trop Dis 2016; 10:e0004483. [PMID: 26943908 PMCID: PMC4778764 DOI: 10.1371/journal.pntd.0004483] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 02/02/2016] [Indexed: 11/18/2022] Open
Abstract
Background Burkholderia pseudomallei is a water and soil bacterium and the causative agent of melioidosis. A characteristic feature of this bacterium is the formation of different colony morphologies which can be isolated from environmental samples as well as from clinical samples, but can also be induced in vitro. Previous studies indicate that morphotypes can differ in a number of characteristics such as resistance to oxidative stress, cellular adhesion and intracellular replication. Yet the metabolic features of B. pseudomallei and its different morphotypes have not been examined in detail so far. Therefore, this study aimed to characterize the exometabolome of B. pseudomallei morphotypes and the impact of acute infection on their metabolic characteristics. Methods and Principal Findings We applied nuclear magnetic resonance spectroscopy (1H-NMR) in a metabolic footprint approach to compare nutrition uptake and metabolite secretion of starvation induced morphotypes of the B. pseudomallei strains K96243 and E8. We observed gluconate production and uptake in all morphotype cultures. Our study also revealed that among all morphotypes amino acids could be classified with regard to their fast and slow consumption. In addition to these shared metabolic features, the morphotypes varied highly in amino acid uptake profiles, secretion of branched chain amino acid metabolites and carbon utilization. After intracellular passage in vitro or murine acute infection in vivo, we observed a switch of the various morphotypes towards a single morphotype and a synchronization of nutrient uptake and metabolite secretion. Conclusion To our knowledge, this study provides first insights into the basic metabolism of B. pseudomallei and its colony morphotypes. Furthermore, our data suggest, that acute infection leads to the synchronization of B. pseudomallei colony morphology and metabolism through yet unknown host signals and bacterial mechanisms. Melioidosis is a common disease in Northern Australia and East Asia, with regional mortality rates of up to 40%. Clinical manifestations range from soft tissue infections to severe sepsis. It is caused by the Gram negative saprophytic water and soil bacterium Burkholderia pseudomallei, which forms a variety of colony morphologies on solid agar. Various morphotypes appear after the bacterium is exposed to physiological stress conditions or underwent the process of infection, yet the physiological function is unclear. Metabolism is closely linked to virulence in many pathogens, and since metabolic data are not available so far for this bacterium, we monitored the nutrition uptake and metabolite secretion of B. pseudomallei morphotypes. Interestingly, despite typical genes responsible for gluconate production are missing in the B. pseudomallei genome, we observed high amounts of gluconate in the extracellular space. Furthermore, we were able to investigate metabolic differences among the morphotypes and identified synchronization in morphology and metabolism after infection as an adaptation to the host environment.
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Affiliation(s)
- Philipp Gierok
- Institute of Biochemistry, Ernst-Moritz-Arndt-University, Greifswald, Germany
| | - Christian Kohler
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
| | - Ivo Steinmetz
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
| | - Michael Lalk
- Institute of Biochemistry, Ernst-Moritz-Arndt-University, Greifswald, Germany
- * E-mail:
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24
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La Rosa R, Behrends V, Williams HD, Bundy JG, Rojo F. Influence of the Crc regulator on the hierarchical use of carbon sources from a complete medium inPseudomonas. Environ Microbiol 2016; 18:807-18. [DOI: 10.1111/1462-2920.13126] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/03/2015] [Accepted: 11/05/2015] [Indexed: 12/01/2022]
Affiliation(s)
- Ruggero La Rosa
- Departamento de Biotecnología Microbiana; Centro Nacional de Biotecnología, CSIC; Darwin 3, Cantoblanco 28049 Madrid Spain
| | - Volker Behrends
- Department of Life Sciences; University of Roehampton; London SW15 4DJ UK
- Department of Surgery and Cancer; Faculty of Medicine; Imperial College London; London SW7 2AZ UK
| | - Huw D. Williams
- Department of Life Sciences; Faculty of Natural Sciences; Imperial College London; London SW7 2AZ UK
| | - Jacob G. Bundy
- Department of Surgery and Cancer; Faculty of Medicine; Imperial College London; London SW7 2AZ UK
| | - Fernando Rojo
- Departamento de Biotecnología Microbiana; Centro Nacional de Biotecnología, CSIC; Darwin 3, Cantoblanco 28049 Madrid Spain
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Zimmermann M, Kuehne A, Boshoff HI, Barry CE, Zamboni N, Sauer U. Dynamic exometabolome analysis reveals active metabolic pathways in non-replicating mycobacteria. Environ Microbiol 2015; 17:4802-15. [PMID: 26373870 PMCID: PMC10500702 DOI: 10.1111/1462-2920.13056] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 09/13/2015] [Accepted: 09/13/2015] [Indexed: 01/01/2023]
Abstract
An organism's metabolic activity leaves an extracellular footprint and dynamic changes in this exometabolome inform about nutrient uptake, waste disposal and signalling activities. Using non-targeted mass spectrometry, we report exometabolome dynamics of hypoxia-induced, non-replicating mycobacteria that are thought to play a role in latent tuberculosis. Despite evidence of active metabolism, little is known about the mechanisms enabling obligate aerobic mycobacteria to cope with hypoxia, resulting in long-term survival and increased chemotherapeutic tolerance. The dynamics of 379 extracellular compounds of Mycobacterium smegmatis were deconvoluted with a genome-scale metabolic reaction-pair network to generate hypotheses about intracellular pathway usage. Time-resolved (13) C-tracing and mutant experiments then demonstrated a crucial, energy-generating role of asparagine utilization and non-generic usage of the glyoxylate shunt for hypoxic fitness. Experiments with M. bovis and M. tuberculosis revealed the general relevance of asparagine fermentation and a variable contribution of the glyoxylate shunt to non-replicative, hypoxic survival between the three species.
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Affiliation(s)
- Michael Zimmermann
- Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
- PhD Program Systems Biology, Life Science Zurich Graduate School, Zurich, Switzerland
| | - Andreas Kuehne
- Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
- PhD Program Systems Biology, Life Science Zurich Graduate School, Zurich, Switzerland
| | - Helena I. Boshoff
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, National Institute for Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Clifton E. Barry
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, National Institute for Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nicola Zamboni
- Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
| | - Uwe Sauer
- Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
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26
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Nikel PI, Chavarría M, Fuhrer T, Sauer U, de Lorenzo V. Pseudomonas putida KT2440 Strain Metabolizes Glucose through a Cycle Formed by Enzymes of the Entner-Doudoroff, Embden-Meyerhof-Parnas, and Pentose Phosphate Pathways. J Biol Chem 2015; 290:25920-32. [PMID: 26350459 DOI: 10.1074/jbc.m115.687749] [Citation(s) in RCA: 215] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Indexed: 01/28/2023] Open
Abstract
The soil bacterium Pseudomonas putida KT2440 lacks a functional Embden-Meyerhof-Parnas (EMP) pathway, and glycolysis is known to proceed almost exclusively through the Entner-Doudoroff (ED) route. To investigate the raison d'être of this metabolic arrangement, the distribution of periplasmic and cytoplasmic carbon fluxes was studied in glucose cultures of this bacterium by using (13)C-labeled substrates, combined with quantitative physiology experiments, metabolite quantification, and in vitro enzymatic assays under both saturating and non-saturating, quasi in vivo conditions. Metabolic flux analysis demonstrated that 90% of the consumed sugar was converted into gluconate, entering central carbon metabolism as 6-phosphogluconate and further channeled into the ED pathway. Remarkably, about 10% of the triose phosphates were found to be recycled back to form hexose phosphates. This set of reactions merges activities belonging to the ED, the EMP (operating in a gluconeogenic fashion), and the pentose phosphate pathways to form an unforeseen metabolic architecture (EDEMP cycle). Determination of the NADPH balance revealed that the default metabolic state of P. putida KT2440 is characterized by a slight catabolic overproduction of reducing power. Cells growing on glucose thus run a biochemical cycle that favors NADPH formation. Because NADPH is required not only for anabolic functions but also for counteracting different types of environmental stress, such a cyclic operation may contribute to the physiological heftiness of this bacterium in its natural habitats.
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Affiliation(s)
- Pablo I Nikel
- From the Systems and Synthetic Biology Program, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Max Chavarría
- the Escuela de Química, Universidad de Costa Rica, 2060 San José, Costa Rica, and
| | - Tobias Fuhrer
- the Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Uwe Sauer
- the Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Víctor de Lorenzo
- From the Systems and Synthetic Biology Program, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain,
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27
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Shommu NS, Vogel HJ, Storey DG. Potential of metabolomics to reveal Burkholderia cepacia complex pathogenesis and antibiotic resistance. Front Microbiol 2015. [PMID: 26217312 PMCID: PMC4499752 DOI: 10.3389/fmicb.2015.00668] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The Burkholderia cepacia complex (Bcc) is a collection of closely related, genetically distinct, ecologically diverse species known to cause life-threatening infections in cystic fibrosis (CF) patients. By virtue of a flexible genomic structure and diverse metabolic activity, Bcc bacteria employ a wide array of virulence factors for pathogenesis in CF patients and have developed resistance to most of the commonly used antibiotics. However, the mechanism of pathogenesis and antibiotic resistance is still not fully understood. This mini review discusses the established and potential virulence determinants of Bcc and some of the contemporary strategies including transcriptomics and proteomics used to identify these traits. We also propose the application of metabolic profiling, a cost-effective modern-day approach to achieve new insights.
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Affiliation(s)
- Nusrat S Shommu
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary , Calgary, AB, Canada
| | - Hans J Vogel
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary , Calgary, AB, Canada
| | - Douglas G Storey
- Microbiology Research Group, Department of Biological Sciences, University of Calgary , Calgary, AB, Canada
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28
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Tatke G, Kumari H, Silva-Herzog E, Ramirez L, Mathee K. Pseudomonas aeruginosa MifS-MifR Two-Component System Is Specific for α-Ketoglutarate Utilization. PLoS One 2015; 10:e0129629. [PMID: 26114434 PMCID: PMC4482717 DOI: 10.1371/journal.pone.0129629] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 05/10/2015] [Indexed: 12/31/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative, metabolically versatile opportunistic pathogen that elaborates a multitude of virulence factors, and is extraordinarily resistant to a gamut of clinically significant antibiotics. This ability, in part, is mediated by two-component regulatory systems (TCS) that play a crucial role in modulating virulence mechanisms and metabolism. MifS (PA5512) and MifR (PA5511) form one such TCS implicated in biofilm formation. MifS is a sensor kinase whereas MifR belongs to the NtrC superfamily of transcriptional regulators that interact with RpoN (σ54). In this study we demonstrate that the mifS and mifR genes form a two-gene operon. The close proximity of mifSR operon to poxB (PA5514) encoding a ß-lactamase hinted at the role of MifSR TCS in regulating antibiotic resistance. To better understand this TCS, clean in-frame deletions were made in P. aeruginosa PAO1 creating PAO∆mifS, PAO∆mifR and PAO∆mifSR. The loss of mifSR had no effect on the antibiotic resistance profile. Phenotypic microarray (BioLOG) analyses of PAO∆mifS and PAO∆mifR revealed that these mutants were unable to utilize C5-dicarboxylate α-ketoglutarate (α-KG), a key tricarboxylic acid cycle intermediate. This finding was confirmed using growth analyses, and the defect can be rescued by mifR or mifSR expressed in trans. These mifSR mutants were able to utilize all the other TCA cycle intermediates (citrate, succinate, fumarate, oxaloacetate or malate) and sugars (glucose or sucrose) except α-KG as the sole carbon source. We confirmed that the mifSR mutants have functional dehydrogenase complex suggesting a possible defect in α-KG transport. The inability of the mutants to utilize α-KG was rescued by expressing PA5530, encoding C5-dicarboxylate transporter, under a regulatable promoter. In addition, we demonstrate that besides MifSR and PA5530, α-KG utilization requires functional RpoN. These data clearly suggests that P. aeruginosa MifSR TCS is involved in sensing α-KG and regulating its transport and subsequent metabolism.
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Affiliation(s)
- Gorakh Tatke
- Department of Biological Sciences, College of Arts & Sciences, Florida International University, Miami, Florida, United States of America
- Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, United States of America
| | - Hansi Kumari
- Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, United States of America
| | - Eugenia Silva-Herzog
- Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, United States of America
| | - Lourdes Ramirez
- Department of Biological Sciences, College of Arts & Sciences, Florida International University, Miami, Florida, United States of America
| | - Kalai Mathee
- Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, United States of America
- * E-mail:
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29
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Convergent evolution and adaptation of Pseudomonas aeruginosa within patients with cystic fibrosis. Nat Genet 2014; 47:57-64. [DOI: 10.1038/ng.3148] [Citation(s) in RCA: 404] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 10/27/2014] [Indexed: 12/30/2022]
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30
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Rohatgi N, Nielsen TK, Bjørn SP, Axelsson I, Paglia G, Voldborg BG, Palsson BO, Rolfsson Ó. Biochemical characterization of human gluconokinase and the proposed metabolic impact of gluconic acid as determined by constraint based metabolic network analysis. PLoS One 2014; 9:e98760. [PMID: 24896608 PMCID: PMC4045858 DOI: 10.1371/journal.pone.0098760] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 05/06/2014] [Indexed: 11/19/2022] Open
Abstract
The metabolism of gluconate is well characterized in prokaryotes where it is known to be degraded following phosphorylation by gluconokinase. Less is known of gluconate metabolism in humans. Human gluconokinase activity was recently identified proposing questions about the metabolic role of gluconate in humans. Here we report the recombinant expression, purification and biochemical characterization of isoform I of human gluconokinase alongside substrate specificity and kinetic assays of the enzyme catalyzed reaction. The enzyme, shown to be a dimer, had ATP dependent phosphorylation activity and strict specificity towards gluconate out of 122 substrates tested. In order to evaluate the metabolic impact of gluconate in humans we modeled gluconate metabolism using steady state metabolic network analysis. The results indicate that significant metabolic flux changes in anabolic pathways linked to the hexose monophosphate shunt (HMS) are induced through a small increase in gluconate concentration. We argue that the enzyme takes part in a context specific carbon flux route into the HMS that, in humans, remains incompletely explored. Apart from the biochemical description of human gluconokinase, the results highlight that little is known of the mechanism of gluconate metabolism in humans despite its widespread use in medicine and consumer products.
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Affiliation(s)
- Neha Rohatgi
- Center for Systems Biology, University of Iceland, Reykjavik, Iceland
- University of Iceland Biomedical Center, Reykjavik, Iceland
| | - Tine Kragh Nielsen
- Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sara Petersen Bjørn
- Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ivar Axelsson
- Center for Systems Biology, University of Iceland, Reykjavik, Iceland
| | - Giuseppe Paglia
- Center for Systems Biology, University of Iceland, Reykjavik, Iceland
| | - Bjørn Gunnar Voldborg
- Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Óttar Rolfsson
- Center for Systems Biology, University of Iceland, Reykjavik, Iceland
- University of Iceland Biomedical Center, Reykjavik, Iceland
- * E-mail:
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31
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Hao J, Liebeke M, Astle W, De Iorio M, Bundy JG, Ebbels TMD. Bayesian deconvolution and quantification of metabolites in complex 1D NMR spectra using BATMAN. Nat Protoc 2014; 9:1416-27. [PMID: 24853927 DOI: 10.1038/nprot.2014.090] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Data processing for 1D NMR spectra is a key bottleneck for metabolomic and other complex-mixture studies, particularly where quantitative data on individual metabolites are required. We present a protocol for automated metabolite deconvolution and quantification from complex NMR spectra by using the Bayesian automated metabolite analyzer for NMR (BATMAN) R package. BATMAN models resonances on the basis of a user-controllable set of templates, each of which specifies the chemical shifts, J-couplings and relative peak intensities for a single metabolite. Peaks are allowed to shift position slightly between spectra, and peak widths are allowed to vary by user-specified amounts. NMR signals not captured by the templates are modeled non-parametrically by using wavelets. The protocol covers setting up user template libraries, optimizing algorithmic input parameters, improving prior information on peak positions, quality control and evaluation of outputs. The outputs include relative concentration estimates for named metabolites together with associated Bayesian uncertainty estimates, as well as the fit of the remainder of the spectrum using wavelets. Graphical diagnostics allow the user to examine the quality of the fit for multiple spectra simultaneously. This approach offers a workflow to analyze large numbers of spectra and is expected to be useful in a wide range of metabolomics studies.
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Affiliation(s)
- Jie Hao
- Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Manuel Liebeke
- 1] Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, UK. [2] Present address: Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - William Astle
- Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada
| | - Maria De Iorio
- Department of Statistical Science, University College London, London, UK
| | - Jacob G Bundy
- Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Timothy M D Ebbels
- Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, UK
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32
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Sokolenko S, Blondeel EJM, Azlah N, George B, Schulze S, Chang D, Aucoin MG. Profiling convoluted single-dimension proton NMR spectra: a Plackett-Burman approach for assessing quantification error of metabolites in complex mixtures with application to cell culture. Anal Chem 2014; 86:3330-7. [PMID: 24555717 DOI: 10.1021/ac4033966] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Single-dimension hydrogen, or proton, nuclear magnetic resonance spectroscopy (1D-(1)H NMR) has become an attractive option for characterizing the full range of components in complex mixtures of small molecular weight compounds due to its relative simplicity, speed, spectral reproducibility, and noninvasive sample preparation protocols compared to alternative methods. One challenge associated with this method is the overlap of NMR resonances leading to "convoluted" spectra. While this can be mitigated through "targeted profiling", there is still the possibility of increased quantification error. This work presents the application of a Plackett-Burman experimental design for the robust estimation of precision and accuracy of 1D-(1)H NMR compound quantification in synthetic mixtures, with application to mammalian cell culture supernatant. A single, 20 sample experiment was able to provide a sufficient estimate of bias and variability at different metabolite concentrations. Two major sources of bias were identified: incorrect interpretation of singlet resonances and the quantification of resonances from protons in close proximity to labile protons. Furthermore, decreases in measurement accuracy and precision could be observed with decreasing concentration for a small fraction of the components as a result of their particular convolution patterns. Finally, the importance of a priori concentration estimates is demonstrated through the example of interpreting acetate metabolite trends from a bioreactor cultivation of Chinese hamster ovary cells expressing a recombinant antibody.
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Affiliation(s)
- Stanislav Sokolenko
- Waterloo Institute for Nanotechnology, Department of Chemical Engineering, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
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33
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Liebeke M, Lalk M. Staphylococcus aureus metabolic response to changing environmental conditions - a metabolomics perspective. Int J Med Microbiol 2013; 304:222-9. [PMID: 24439195 DOI: 10.1016/j.ijmm.2013.11.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Revised: 10/30/2013] [Accepted: 11/25/2013] [Indexed: 01/16/2023] Open
Abstract
Microorganisms preserve their metabolic function against a wide range of external perturbations including biotic or abiotic factors by utilizing cellular adaptations to maintain cell homeostasis. Functional genomics aims to detect such adaptive alterations on the level of transcriptome, proteome and metabolome to understand system wide changes and to identify interactions between the different levels of biochemical organization. Microbial metabolomics measures metabolites, the direct biochemical response to the environment, and is pivotal to the understanding of the variability and dynamics of bacterial cell metabolism. Metabolomics can measure many different types of compounds including primary metabolites, secondary metabolites, second messengers, quorum sensing compounds and others, which all contribute to the complex bacterial response to an environmental change. Recent data confirmed that many metabolic processes in pathogenic bacteria are linked to virulence and invasive capabilities. Deciphering bacterial metabolism in response to specific environmental conditions and in specific genetic backgrounds will help map the complex network between the metabolome and the other "-omes". Here, we will review a selection of case studies for the pathogenic Gram-positive bacterium Staphylococcus aureus and summarize the current state of metabolomics literature covering staphylococci metabolism under different physiological states.
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Affiliation(s)
- Manuel Liebeke
- Biomolecular Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK.
| | - Michael Lalk
- Institute of Biochemistry, Ernst-Moritz-Arndt-University of Greifswald, 17487 Greifswald, Germany
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34
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Corsaro C, Mallamace D, Łojewska J, Mallamace F, Pietronero L, Missori M. Molecular degradation of ancient documents revealed by 1H HR-MAS NMR spectroscopy. Sci Rep 2013; 3:2896. [PMID: 24104201 PMCID: PMC3793219 DOI: 10.1038/srep02896] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 09/23/2013] [Indexed: 11/09/2022] Open
Abstract
For centuries mankind has stored its knowledge on paper, a remarkable biomaterial made of natural cellulose fibers. However, spontaneous cellulose degradation phenomena weaken and discolorate paper over time. The detailed knowledge of products arising from cellulose degradation is essential in understanding deterioration pathways and in improving durability of cultural heritage. In this study, for the first time, products of cellulose degradation were individually detected in solid paper samples by means of an extremely powerful proton HR-MAS NMR set-up, in combination to a wise use of both ancient and, as reference, artificially aged paper samples. Carboxylic acids, in addition to more complex dicarboxylic and hydroxy-carboxylic acids, were found in all samples studied. Since these products can catalyze further degradation, their knowledge is fundamental to improve conservation strategies of historical documents. Furthermore, the identification of compounds used in ancient production techniques, also suggests for artifacts dating, authentication and provenance.
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Affiliation(s)
- Carmelo Corsaro
- Dipartimento di Fisica e Scienze della Terra and CNISM, Università di Messina, Viale F. Stagno d'Alcontres 31, I-98166, Messina, Italy
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