1
|
Butin N, Bergès C, Portais JC, Bellvert F. An optimization method for untargeted MS-based isotopic tracing investigations of metabolism. Metabolomics 2022; 18:41. [PMID: 35713733 PMCID: PMC9205802 DOI: 10.1007/s11306-022-01897-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 05/17/2022] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Stable isotope tracer studies are increasingly applied to explore metabolism from the detailed analysis of tracer incorporation into metabolites. Untargeted LC/MS approaches have recently emerged and provide potent methods for expanding the dimension and complexity of the metabolic networks that can be investigated. A number of software tools have been developed to process the highly complex MS data collected in such studies; however, a method to optimize the extraction of valuable isotopic data is lacking. OBJECTIVES To develop and validate a method to optimize automated data processing for untargeted MS-based isotopic tracing investigations of metabolism. METHODS The method is based on the application of a suitable reference material to rationally perform parameter optimization throughout the complete data processing workflow. It was applied in the context of 13C-labelling experiments and with two different software, namely geoRge and X13CMS. It was illustrated with the study of a E. coli mutant impaired for central metabolism. RESULTS The optimization methodology provided significant gain in the number and quality of extracted isotopic data, independently of the software considered. Pascal triangle samples are well suited for such purpose since they allow both the identification of analytical issues and optimization of data processing at the same time. CONCLUSION The proposed method maximizes the biological value of untargeted MS-based isotopic tracing investigations by revealing the full metabolic information that is encoded in the labelling patterns of metabolites.
Collapse
Affiliation(s)
- Noémie Butin
- RESTORE, CNRS ERL5311, EFS, ENVT, Inserm U1031, UPS, Université de Toulouse, Toulouse, France
- Toulouse Biotechnology Institute, TBI-INSA de Toulouse INSA/ CNRS 5504-UMR INSA/INRA 792, 5504, Toulouse, France
- MetaboHUB-MetaToul, National Infrastructure of Metabolomics and Fluxomics, 31077, Toulouse, France
| | - Cécilia Bergès
- Toulouse Biotechnology Institute, TBI-INSA de Toulouse INSA/ CNRS 5504-UMR INSA/INRA 792, 5504, Toulouse, France
- MetaboHUB-MetaToul, National Infrastructure of Metabolomics and Fluxomics, 31077, Toulouse, France
| | - Jean-Charles Portais
- RESTORE, CNRS ERL5311, EFS, ENVT, Inserm U1031, UPS, Université de Toulouse, Toulouse, France
- Toulouse Biotechnology Institute, TBI-INSA de Toulouse INSA/ CNRS 5504-UMR INSA/INRA 792, 5504, Toulouse, France
- MetaboHUB-MetaToul, National Infrastructure of Metabolomics and Fluxomics, 31077, Toulouse, France
| | - Floriant Bellvert
- Toulouse Biotechnology Institute, TBI-INSA de Toulouse INSA/ CNRS 5504-UMR INSA/INRA 792, 5504, Toulouse, France.
- MetaboHUB-MetaToul, National Infrastructure of Metabolomics and Fluxomics, 31077, Toulouse, France.
| |
Collapse
|
2
|
Landmesser A, Scherer M, Scherer G, Sarkar M, Edmiston JS, Niessner R, Pluym N. Assessment of the potential vaping-related exposure to carbonyls and epoxides using stable isotope-labeled precursors in the e-liquid. Arch Toxicol 2021; 95:2667-2676. [PMID: 34159432 PMCID: PMC8298337 DOI: 10.1007/s00204-021-03097-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 06/15/2021] [Indexed: 12/28/2022]
Abstract
The formation of carbonyls and epoxides in e-cigarette (EC) aerosol is possible due to heating of the liquid constituents. However, high background levels of these compounds have inhibited a clear assessment of exposure during use of ECs. An EC containing an e-liquid replaced with 10% of 13C-labeled propylene glycol and glycerol was used in a controlled use clinical study with 20 EC users. In addition, five smokers smoked cigarettes spiked with the described e-liquid. Seven carbonyls (formaldehyde, acetaldehyde, acrolein, acetone, crotonaldehyde, methacrolein, propionaldehyde) were measured in the aerosol and the mainstream smoke. Corresponding biomarkers of exposure were determined in the user’s urine samples. 13C-labeled formaldehyde, acetaldehyde and acrolein were found in EC aerosol, while all seven labeled carbonyls were detected in smoke. The labeled biomarkers of exposure to formaldehyde (13C-thiazolidine carboxylic acid and 13C-N-(1,3-thiazolidine-4-carbonyl)glycine), acrolein (13C3-3-hydroxypropylmercapturic acid) and glycidol (13C3-dihydroxypropylmercapturic acid) were present in the urine of vapers indicating an EC use-specific exposure to these toxicants. However, other sources than vaping contribute to a much higher extent by several orders of magnitude to the overall exposure of these toxicants. Comparing data for the native (unlabeled) and the labeled (exposure-specific) biomarkers revealed vaping as a minor source of user’s exposure to these toxicants while other carbonyls and epoxides were not detectable in the EC aerosol.
Collapse
Affiliation(s)
- Anne Landmesser
- ABF Analytisch-Biologisches Forschungslabor GmbH, Semmelweisstrasse 5, 82152, Planegg, Germany.,Chair for Analytical Chemistry, Technische Universität München, Marchioninistraße, Munich, Germany
| | - Max Scherer
- ABF Analytisch-Biologisches Forschungslabor GmbH, Semmelweisstrasse 5, 82152, Planegg, Germany
| | - Gerhard Scherer
- ABF Analytisch-Biologisches Forschungslabor GmbH, Semmelweisstrasse 5, 82152, Planegg, Germany
| | - Mohamadi Sarkar
- Altria Client Services LLC, Center for Research and Technology, Richmond, VA, USA
| | - Jeffery S Edmiston
- Altria Client Services LLC, Center for Research and Technology, Richmond, VA, USA
| | - Reinhard Niessner
- Chair for Analytical Chemistry, Technische Universität München, Marchioninistraße, Munich, Germany
| | - Nikola Pluym
- ABF Analytisch-Biologisches Forschungslabor GmbH, Semmelweisstrasse 5, 82152, Planegg, Germany.
| |
Collapse
|
3
|
Evers B, Gerding A, Boer T, Heiner-Fokkema MR, Jalving M, Wahl SA, Reijngoud DJ, Bakker BM. Simultaneous Quantification of the Concentration and Carbon Isotopologue Distribution of Polar Metabolites in a Single Analysis by Gas Chromatography and Mass Spectrometry. Anal Chem 2021; 93:8248-8256. [PMID: 34060804 PMCID: PMC8253487 DOI: 10.1021/acs.analchem.1c01040] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
13C-isotope tracing is a frequently employed approach to study metabolic pathway activity. When combined with the subsequent quantification of absolute metabolite concentrations, this enables detailed characterization of the metabolome in biological specimens and facilitates computational time-resolved flux quantification. Classically, a 13C-isotopically labeled sample is required to quantify 13C-isotope enrichments and a second unlabeled sample for the quantification of metabolite concentrations. The rationale for a second unlabeled sample is that the current methods for metabolite quantification rely mostly on isotope dilution mass spectrometry (IDMS) and thus isotopically labeled internal standards are added to the unlabeled sample. This excludes the absolute quantification of metabolite concentrations in 13C-isotopically labeled samples. To address this issue, we have developed and validated a new strategy using an unlabeled internal standard to simultaneously quantify metabolite concentrations and 13C-isotope enrichments in a single 13C-labeled sample based on gas chromatography-mass spectrometry (GC/MS). The method was optimized for amino acids and citric acid cycle intermediates and was shown to have high analytical precision and accuracy. Metabolite concentrations could be quantified in small tissue samples (≥20 mg). Also, we applied the method on 13C-isotopically labeled mammalian cells treated with and without a metabolic inhibitor. We proved that we can quantify absolute metabolite concentrations and 13C-isotope enrichments in a single 13C-isotopically labeled sample.
Collapse
Affiliation(s)
- Bernard Evers
- Laboratory of Pediatrics, Section Systems Medicine of Metabolism and Signalling, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Albert Gerding
- Laboratory of Pediatrics, Section Systems Medicine of Metabolism and Signalling, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.,Laboratory of Metabolic Diseases, Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
| | - Theo Boer
- Laboratory of Metabolic Diseases, Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
| | - M Rebecca Heiner-Fokkema
- Laboratory of Metabolic Diseases, Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
| | - Mathilde Jalving
- Department of Medical Oncology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - S Aljoscha Wahl
- Department of Biotechnology, Applied Science Faculty, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Dirk-Jan Reijngoud
- Laboratory of Pediatrics, Section Systems Medicine of Metabolism and Signalling, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Barbara M Bakker
- Laboratory of Pediatrics, Section Systems Medicine of Metabolism and Signalling, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| |
Collapse
|
4
|
Donatti A, Canto AM, Godoi AB, da Rosa DC, Lopes-Cendes I. Circulating Metabolites as Potential Biomarkers for Neurological Disorders-Metabolites in Neurological Disorders. Metabolites 2020; 10:E389. [PMID: 33003305 PMCID: PMC7601919 DOI: 10.3390/metabo10100389] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/11/2022] Open
Abstract
There are, still, limitations to predicting the occurrence and prognosis of neurological disorders. Biomarkers are molecules that can change in different conditions, a feature that makes them potential tools to improve the diagnosis of disease, establish a prognosis, and monitor treatments. Metabolites can be used as biomarkers, and are small molecules derived from the metabolic process found in different biological media, such as tissue samples, cells, or biofluids. They can be identified using various strategies, targeted or untargeted experiments, and by different techniques, such as high-performance liquid chromatography, mass spectrometry, or nuclear magnetic resonance. In this review, we aim to discuss the current knowledge about metabolites as biomarkers for neurological disorders. We will present recent developments that show the need and the feasibility of identifying such biomarkers in different neurological disorders, as well as discuss relevant research findings in the field of metabolomics that are helping to unravel the mechanisms underlying neurological disorders. Although several relevant results have been reported in metabolomic studies in patients with neurological diseases, there is still a long way to go for the clinical use of metabolites as potential biomarkers in these disorders, and more research in the field is needed.
Collapse
Affiliation(s)
- Amanda Donatti
- Department of Medical Genetics and Genomic Medicine, School of Medical Sciences, University of Campinas (UNICAMP), Tessália Vieira de Camargo, 126 Cidade Universitária “Zeferino Vaz”, Campinas SP 13083-887, Brazil; (A.D.); (A.M.C.); (A.B.G.); (D.C.d.R.)
- Brazilian Institute of Neuroscience and Neurotechnology, Campinas SP 13083-887, Brazil
| | - Amanda M. Canto
- Department of Medical Genetics and Genomic Medicine, School of Medical Sciences, University of Campinas (UNICAMP), Tessália Vieira de Camargo, 126 Cidade Universitária “Zeferino Vaz”, Campinas SP 13083-887, Brazil; (A.D.); (A.M.C.); (A.B.G.); (D.C.d.R.)
- Brazilian Institute of Neuroscience and Neurotechnology, Campinas SP 13083-887, Brazil
| | - Alexandre B. Godoi
- Department of Medical Genetics and Genomic Medicine, School of Medical Sciences, University of Campinas (UNICAMP), Tessália Vieira de Camargo, 126 Cidade Universitária “Zeferino Vaz”, Campinas SP 13083-887, Brazil; (A.D.); (A.M.C.); (A.B.G.); (D.C.d.R.)
- Brazilian Institute of Neuroscience and Neurotechnology, Campinas SP 13083-887, Brazil
| | - Douglas C. da Rosa
- Department of Medical Genetics and Genomic Medicine, School of Medical Sciences, University of Campinas (UNICAMP), Tessália Vieira de Camargo, 126 Cidade Universitária “Zeferino Vaz”, Campinas SP 13083-887, Brazil; (A.D.); (A.M.C.); (A.B.G.); (D.C.d.R.)
- Brazilian Institute of Neuroscience and Neurotechnology, Campinas SP 13083-887, Brazil
| | - Iscia Lopes-Cendes
- Department of Medical Genetics and Genomic Medicine, School of Medical Sciences, University of Campinas (UNICAMP), Tessália Vieira de Camargo, 126 Cidade Universitária “Zeferino Vaz”, Campinas SP 13083-887, Brazil; (A.D.); (A.M.C.); (A.B.G.); (D.C.d.R.)
- Brazilian Institute of Neuroscience and Neurotechnology, Campinas SP 13083-887, Brazil
| |
Collapse
|
5
|
Godard T, Zühlke D, Richter G, Wall M, Rohde M, Riedel K, Poblete-Castro I, Krull R, Biedendieck R. Metabolic Rearrangements Causing Elevated Proline and Polyhydroxybutyrate Accumulation During the Osmotic Adaptation Response of Bacillus megaterium. Front Bioeng Biotechnol 2020; 8:47. [PMID: 32161752 PMCID: PMC7053513 DOI: 10.3389/fbioe.2020.00047] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 01/21/2020] [Indexed: 12/15/2022] Open
Abstract
For many years now, Bacillus megaterium serves as a microbial workhorse for the high-level production of recombinant proteins in the g/L-scale. However, efficient and stable production processes require the knowledge of the molecular adaptation strategies of the host organism to establish optimal environmental conditions. Here, we interrogated the osmotic stress response of B. megaterium using transcriptome, proteome, metabolome, and fluxome analyses. An initial transient adaptation consisted of potassium import and glutamate counterion synthesis. The massive synthesis of the compatible solute proline constituted the second longterm adaptation process. Several stress response enzymes involved in iron scavenging and reactive oxygen species (ROS) fighting proteins showed higher levels under prolonged osmotic stress induced by 1.8 M NaCl. At the same time, the downregulation of the expression of genes of the upper part of glycolysis resulted in the activation of the pentose phosphate pathway (PPP), generating an oversupply of NADPH. The increased production of lactate accompanied by the reduction of acetate secretion partially compensate for the unbalanced (NADH/NAD+) ratio. Besides, the tricarboxylic acid cycle (TCA) mainly supplies the produced NADH, as indicated by the higher mRNA and protein levels of involved enzymes, and further confirmed by 13C flux analyses. As a consequence of the metabolic flux toward acetyl-CoA and the generation of an excess of NADPH, B. megaterium redirected the produced acetyl-CoA toward the polyhydroxybutyrate (PHB) biosynthetic pathway accumulating around 30% of the cell dry weight (CDW) as PHB. This direct relation between osmotic stress and intracellular PHB content has been evidenced for the first time, thus opening new avenues for synthesizing this valuable biopolymer using varying salt concentrations under non-limiting nutrient conditions.
Collapse
Affiliation(s)
- Thibault Godard
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
| | - Daniela Zühlke
- Institute of Microbiology, Universität Greifswald, Greifswald, Germany
| | - Georg Richter
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
| | - Melanie Wall
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Katharina Riedel
- Institute of Microbiology, Universität Greifswald, Greifswald, Germany
| | - Ignacio Poblete-Castro
- Biosystems Engineering Laboratory, Center for Bioinformatics and Integrative Biology, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
| | - Rainer Krull
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany.,Center of Pharmaceutical Engineering (PVZ), Technische Universität Braunschweig, Braunschweig, Germany
| | - Rebekka Biedendieck
- Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany.,Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
| |
Collapse
|
6
|
Landmesser A, Scherer M, Pluym N, Sarkar M, Edmiston J, Niessner R, Scherer G. Biomarkers of Exposure Specific to E-vapor Products Based on Stable-Isotope Labeled Ingredients. Nicotine Tob Res 2018; 21:314-322. [DOI: 10.1093/ntr/nty204] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 09/24/2018] [Indexed: 12/21/2022]
Affiliation(s)
- Anne Landmesser
- ABF Analytisch-Biologisches Forschungslabor GmbH, Semmelweisstrasse, Planegg, Germany
- Chair for Analytical Chemistry, Technische Universität München, Marchioninistraße, Munich, Germany
| | - Max Scherer
- ABF Analytisch-Biologisches Forschungslabor GmbH, Semmelweisstrasse, Planegg, Germany
| | - Nikola Pluym
- ABF Analytisch-Biologisches Forschungslabor GmbH, Semmelweisstrasse, Planegg, Germany
| | - Mohamadi Sarkar
- Altria Client Services LLC, Center for Research and Technology, Richmond, VA
| | - Jeffery Edmiston
- Altria Client Services LLC, Center for Research and Technology, Richmond, VA
| | - Reinhard Niessner
- Chair for Analytical Chemistry, Technische Universität München, Marchioninistraße, Munich, Germany
| | - Gerhard Scherer
- ABF Analytisch-Biologisches Forschungslabor GmbH, Semmelweisstrasse, Planegg, Germany
| |
Collapse
|
7
|
Qian X, Zhang Y, Lun DS, Dismukes GC. Rerouting of Metabolism into Desired Cellular Products by Nutrient Stress: Fluxes Reveal the Selected Pathways in Cyanobacterial Photosynthesis. ACS Synth Biol 2018; 7:1465-1476. [PMID: 29617123 DOI: 10.1021/acssynbio.8b00116] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Boosting cellular growth rates while redirecting metabolism to make desired products are the preeminent goals of gene engineering of photoautotrophs, yet so far these goals have been hardly achieved owing to lack of understanding of the functional pathways and their choke points. Here we apply a 13C mass isotopic method (INST-MFA) to quantify instantaneous fluxes of metabolites during photoautotrophic growth. INST-MFA determines the globally most accurate set of absolute fluxes for each metabolite from a finite set of measured 13C-isotopomer fluxes by minimizing the sum of squared residuals between experimental and predicted mass isotopomers. We show that the widely observed shift in biomass composition in cyanobacteria, demonstrated here with Synechococcus sp. PCC 7002, favoring glycogen synthesis during nitrogen starvation is caused by (1) increased flux through a bottleneck step in gluconeogenesis (3PG → GAP/DHAP), and (2) flux overflow through a previously unrecognized hybrid gluconeogenesis-pentose phosphate (hGPP) pathway. Our data suggest the slower growth rate and biomass accumulation under N starvation is due to a reduced carbon fixation rate and a reduced flux of carbon into amino acid precursors. Additionally, 13C flux from α-ketoglutarate to succinate is demonstrated to occur via succinic semialdehyde, an alternative to the conventional TCA cycle, in Synechococcus 7002 under photoautotrophic conditions. We found that pyruvate and oxaloacetate are synthesized mainly by malate dehydrogenase with minimal flux into acetyl coenzyme-A via pyruvate dehydrogenase. Nutrient stress induces major shifts in fluxes into new pathways that deviate from historical metabolic pathways derived from model bacteria.
Collapse
Affiliation(s)
- Xiao Qian
- Waksman Institute, Rutgers University, New Brunswick, New Jersey 08854, United States
| | - Yuan Zhang
- Waksman Institute, Rutgers University, New Brunswick, New Jersey 08854, United States
| | - Desmond S. Lun
- Center for Computational and Integrative Biology, Rutgers University, Camden, New Jersey 08102, United States
- Department of Computer Science, Rutgers University, Camden, New Jersey 08102, United States
- Department of Plant Biology, Rutgers University, New Brunswick, New Jersey 08901, United States
| | - G. Charles Dismukes
- Waksman Institute, Rutgers University, New Brunswick, New Jersey 08854, United States
- Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
| |
Collapse
|
8
|
Golubeva LI, Shupletsov MS, Mashko SV. Metabolic Flux Analysis using 13C Isotopes: III. Significance for Systems Biology and Metabolic Engineering. APPL BIOCHEM MICRO+ 2018. [DOI: 10.1134/s0003683817090058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
9
|
Sinnaeve D, Dinclaux M, Cahoreau E, Millard P, Portais JC, Létisse F, Lippens G. Improved Isotopic Profiling by Pure Shift Heteronuclear 2D J-Resolved NMR Spectroscopy. Anal Chem 2018; 90:4025-4031. [DOI: 10.1021/acs.analchem.7b05206] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Davy Sinnaeve
- NMR and Structure Analysis Unit, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, B-9000, Belgium
| | - Mickael Dinclaux
- LISBP, Université de Toulouse, CNRS, INRA, INSA, Toulouse, 31077, France
| | - Edern Cahoreau
- LISBP, Université de Toulouse, CNRS, INRA, INSA, Toulouse, 31077, France
| | - Pierre Millard
- LISBP, Université de Toulouse, CNRS, INRA, INSA, Toulouse, 31077, France
| | | | - Fabien Létisse
- LISBP, Université de Toulouse, CNRS, INRA, INSA, Toulouse, 31077, France
| | - Guy Lippens
- LISBP, Université de Toulouse, CNRS, INRA, INSA, Toulouse, 31077, France
| |
Collapse
|
10
|
Morales Y, Bosque G, Vehí J, Picó J, Llaneras F. PFA toolbox: a MATLAB tool for Metabolic Flux Analysis. BMC SYSTEMS BIOLOGY 2016; 10:46. [PMID: 27401090 PMCID: PMC4940746 DOI: 10.1186/s12918-016-0284-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Accepted: 06/01/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND Metabolic Flux Analysis (MFA) is a methodology that has been successfully applied to estimate metabolic fluxes in living cells. However, traditional frameworks based on this approach have some limitations, particularly when measurements are scarce and imprecise. This is very common in industrial environments. The PFA Toolbox can be used to face those scenarios. RESULTS Here we present the PFA (Possibilistic Flux Analysis) Toolbox for MATLAB, which simplifies the use of Interval and Possibilistic Metabolic Flux Analysis. The main features of the PFA Toolbox are the following: (a) It provides reliable MFA estimations in scenarios where only a few fluxes can be measured or those available are imprecise. (b) It provides tools to easily plot the results as interval estimates or flux distributions. (c) It is composed of simple functions that MATLAB users can apply in flexible ways. (d) It includes a Graphical User Interface (GUI), which provides a visual representation of the measurements and their uncertainty. (e) It can use stoichiometric models in COBRA format. In addition, the PFA Toolbox includes a User's Guide with a thorough description of its functions and several examples. CONCLUSIONS The PFA Toolbox for MATLAB is a freely available Toolbox that is able to perform Interval and Possibilistic MFA estimations.
Collapse
Affiliation(s)
- Yeimy Morales
- MICElab, IIIA, Universitat de Girona, Campus Montilivi, P4, Girona, 17071, Spain.
| | - Gabriel Bosque
- Institut Universitari d'Automàtica i Informàtica Industrial, Universitat Politècnica de València, Camino de Vera s/n, Edificio 5C, 46022, Valencia, Spain
| | - Josep Vehí
- MICElab, IIIA, Universitat de Girona, Campus Montilivi, P4, Girona, 17071, Spain
| | - Jesús Picó
- Institut Universitari d'Automàtica i Informàtica Industrial, Universitat Politècnica de València, Camino de Vera s/n, Edificio 5C, 46022, Valencia, Spain
| | - Francisco Llaneras
- MICElab, IIIA, Universitat de Girona, Campus Montilivi, P4, Girona, 17071, Spain
| |
Collapse
|
11
|
Kohlstedt M, Sappa PK, Meyer H, Maaß S, Zaprasis A, Hoffmann T, Becker J, Steil L, Hecker M, van Dijl JM, Lalk M, Mäder U, Stülke J, Bremer E, Völker U, Wittmann C. Adaptation ofBacillus subtiliscarbon core metabolism to simultaneous nutrient limitation and osmotic challenge: a multi-omics perspective. Environ Microbiol 2014; 16:1898-917. [DOI: 10.1111/1462-2920.12438] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 02/18/2014] [Indexed: 01/24/2023]
Affiliation(s)
- Michael Kohlstedt
- Institute of Systems Biotechnology; Saarland University; Campus A1 5 66123 Saarbrücken Germany
- Institute of Biochemical Engineering; Braunschweig University of Technology; Braunschweig Germany
| | - Praveen K. Sappa
- Interfaculty Institute of Genetics and Functional Genomics; Department Functional Genomics; University Medicine Greifswald; Germany
| | - Hanna Meyer
- Institutes of Biochemistry; Ernst-Moritz-Arndt-University Greifswald; Greifswald Germany
| | - Sandra Maaß
- Microbiology; Ernst-Moritz-Arndt-University Greifswald; Greifswald Germany
| | - Adrienne Zaprasis
- Department of Biology; Laboratory of Microbiology; Philipps-University Marburg; Marburg Germany
| | - Tamara Hoffmann
- Department of Biology; Laboratory of Microbiology; Philipps-University Marburg; Marburg Germany
| | - Judith Becker
- Institute of Systems Biotechnology; Saarland University; Campus A1 5 66123 Saarbrücken Germany
- Institute of Biochemical Engineering; Braunschweig University of Technology; Braunschweig Germany
| | - Leif Steil
- Interfaculty Institute of Genetics and Functional Genomics; Department Functional Genomics; University Medicine Greifswald; Germany
| | - Michael Hecker
- Microbiology; Ernst-Moritz-Arndt-University Greifswald; Greifswald Germany
| | - Jan Maarten van Dijl
- Department of Medical Microbiology; University of Groningen; University Medical Center Groningen; Groningen The Netherlands
| | - Michael Lalk
- Institutes of Biochemistry; Ernst-Moritz-Arndt-University Greifswald; Greifswald Germany
| | - Ulrike Mäder
- Interfaculty Institute of Genetics and Functional Genomics; Department Functional Genomics; University Medicine Greifswald; Germany
| | - Jörg Stülke
- Department for General Microbiology; Georg-August-University Göttingen; Göttingen Germany
| | - Erhard Bremer
- Department of Biology; Laboratory of Microbiology; Philipps-University Marburg; Marburg Germany
| | - Uwe Völker
- Interfaculty Institute of Genetics and Functional Genomics; Department Functional Genomics; University Medicine Greifswald; Germany
| | - Christoph Wittmann
- Institute of Systems Biotechnology; Saarland University; Campus A1 5 66123 Saarbrücken Germany
- Institute of Biochemical Engineering; Braunschweig University of Technology; Braunschweig Germany
| |
Collapse
|
12
|
Abstract
Glutamine has recently emerged as a key substrate to support cancer cell proliferation, and the quantification of its metabolic flux is essential to understand the mechanisms by which this amino acid participates in the metabolic rewiring that sustains the survival and growth of neoplastic cells. Glutamine metabolism involves two major routes, glutaminolysis and reductive carboxylation, both of which begin with the deamination of glutamine to glutamate and the conversion of glutamate into α-ketoglutarate. In glutaminolysis, α-ketoglutarate is oxidized via the tricarboxylic acid cycle and decarboxylated to pyruvate. In reductive carboxylation, α-ketoglutarate is reductively converted into isocitrate, which is isomerized to citrate to supply acetyl-CoA for de novo lipogenesis. Here, we describe methods to quantify the metabolic flux of glutamine through these two routes, as well as the contribution of glutamine to lipid synthesis. Examples of how these methods can be applied to study metabolic pathways of oncological relevance are provided.
Collapse
|
13
|
Tang JKH, You L, Blankenship RE, Tang YJ. Recent advances in mapping environmental microbial metabolisms through 13C isotopic fingerprints. J R Soc Interface 2012; 9:2767-80. [PMID: 22896564 DOI: 10.1098/rsif.2012.0396] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
After feeding microbes with a defined (13)C substrate, unique isotopic patterns (isotopic fingerprints) can be formed in their metabolic products. Such labelling information not only can provide novel insights into functional pathways but also can determine absolute carbon fluxes through the metabolic network via metabolic modelling approaches. This technique has been used for finding pathways that may have been mis-annotated in the past, elucidating new enzyme functions, and investigating cell metabolisms in microbial communities. In this review paper, we summarize the applications of (13)C approaches to analyse novel cell metabolisms for the past 3 years. The isotopic fingerprints (defined as unique isotopomers useful for pathway identifications) have revealed the operations of the Entner-Doudoroff pathway, the reverse tricarboxylic acid cycle, new enzymes for biosynthesis of central metabolites, diverse respiration routes in phototrophic metabolism, co-metabolism of carbon nutrients and novel CO(2) fixation pathways. This review also discusses new isotopic methods to map carbon fluxes in global metabolisms, as well as potential factors influencing the metabolic flux quantification (e.g. metabolite channelling, the isotopic purity of (13)C substrates and the isotopic effect). Although (13)C labelling is not applicable to all biological systems (e.g. microbial communities), recent studies have shown that this method has a significant value in functional characterization of poorly understood micro-organisms, including species relevant for biotechnology and human health.
Collapse
Affiliation(s)
- Joseph Kuo-Hsiang Tang
- Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, MA 01610, USA
| | | | | | | |
Collapse
|
14
|
Investigating the effects of perturbations to pgi and eno gene expression on central carbon metabolism in Escherichia coli using (13)C metabolic flux analysis. Microb Cell Fact 2012; 11:87. [PMID: 22721472 PMCID: PMC3778843 DOI: 10.1186/1475-2859-11-87] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 06/09/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND It has long been recognized that analyzing the behaviour of the complex intracellular biological networks is important for breeding industrially useful microorganisms. However, because of the complexity of these biological networks, it is currently not possible to obtain all the desired microorganisms. In this study, we constructed a system for analyzing the effect of gene expression perturbations on the behavior of biological networks in Escherichia coli. Specifically, we utilized (13)C metabolic flux analysis ((13)C-MFA) to analyze the effect of perturbations to the expression levels of pgi and eno genes encoding phosphoglucose isomerase and enolase, respectively on metabolic fluxes. RESULTS We constructed gene expression-controllable E. coli strains using a single-copy mini F plasmid. Using the pgi expression-controllable strain, we found that the specific growth rate correlated with the pgi expression level. (13)C-MFA of this strain revealed that the fluxes for the pentose phosphate pathway and Entner-Doudoroff pathway decreased, as the pgi expression lelvel increased. In addition, the glyoxylate shunt became active when the pgi expression level was almost zero. Moreover, the flux for the glyoxylate shunt increased when the pgi expression level decreased, but was significantly reduced in the pgi-knockout cells. Comparatively, eno expression could not be decreased compared to the parent strain, but we found that increased eno expression resulted in a decreased specific growth rate. (13)C-MFA revealed that the metabolic flux distribution was not altered by an increased eno expression level, but the overall metabolic activity of the central metabolism decreased. Furthermore, to evaluate the impact of perturbed expression of pgi and eno genes on changes in metabolic fluxes in E. coli quantitatively, metabolic sensitivity analysis was performed. As a result, the perturbed expression of pgi gene had a great impact to the metabolic flux changes in the branch point between the glycolysis and pentose phosphate pathway, isocitrate dehydrogenase reaction, anaplerotic pathways and Entner-Doudoroff pathway. In contrast, the impact of perturbed eno expression to the flux changes in E. coli metabolic network was small. CONCLUSIONS Our results indicate that the response of metabolic fluxes to perturbation to pgi expression was different from that to eno expression; perturbations to pgi expression affect the reaction related to the Pgi protein function, the isocitrate dehydrogenase reaction, anaplerotic reactions and Entner-Doudoroff pathway. Meanwhile, eno expression seems to affect the overall metabolic activity, and the impact of perturbed eno expression on metabolic flux change is small. Using the gene expression control system reported here, it is expected that we can analyze the response and adaptation process of complex biological networks to gene expression perturbations.
Collapse
|
15
|
Stable isotope peptide mass spectrometry to decipher amino acid metabolism in Dehalococcoides strain CBDB1. J Bacteriol 2012; 194:4169-77. [PMID: 22661690 DOI: 10.1128/jb.00049-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Dehalococcoides species are key players in the anaerobic transformation of halogenated solvents at contaminated sites. Here, we analyze isotopologue distributions in amino acid pools from peptides of Dehalococcoides strain CBDB1 after incubation with (13)C-labeled acetate or bicarbonate as a carbon source. The resulting data were interpreted with regard to genome annotations to identify amino acid biosynthesis pathways. In addition to using gas chromatography-mass spectrometry (GC-MS) for analyzing derivatized amino acids after protein hydrolysis, we introduce a second, much milder method, in which we directly analyze peptide masses after tryptic digest and peptide fragments by nano-liquid chromatography-electrospray ionization-tandem mass spectrometry (nano-LC-ESI-MS/MS). With this method, we identify isotope incorporation patterns for 17 proteinaceous amino acids, including proline, cysteine, lysine, and arginine, which escaped previous analyses in Dehalococcoides. Our results confirmed lysine biosynthesis via the α-aminoadipate pathway, precluding lysine formation from aspartate. Similarly, the isotopologue pattern obtained for arginine provided biochemical evidence of its synthesis from glutamate. Direct peptide MS/MS analysis of the labeling patterns of glutamine and asparagine, which were converted to glutamate and aspartate during protein hydrolysis, gave biochemical evidence of their precursors and confirmed glutamate biosynthesis via a Re-specific citrate synthase. By addition of unlabeled free amino acids to labeled cells, we show that in strain CBDB1 none of the 17 tested amino acids was incorporated into cell mass, indicating that they are all synthesized de novo. Our approach is widely applicable and provides a means to analyze amino acid metabolism by studying specific proteins even in mixed consortia.
Collapse
|
16
|
Crown SB, Ahn WS, Antoniewicz MR. Rational design of ¹³C-labeling experiments for metabolic flux analysis in mammalian cells. BMC SYSTEMS BIOLOGY 2012; 6:43. [PMID: 22591686 PMCID: PMC3490712 DOI: 10.1186/1752-0509-6-43] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 04/17/2012] [Indexed: 01/24/2023]
Abstract
Background 13C-Metabolic flux analysis (13C-MFA) is a standard technique to probe cellular metabolism and elucidate in vivo metabolic fluxes. 13C-Tracer selection is an important step in conducting 13C-MFA, however, current methods are restricted to trial-and-error approaches, which commonly focus on an arbitrary subset of the tracer design space. To systematically probe the complete tracer design space, especially for complex systems such as mammalian cells, there is a pressing need for new rational approaches to identify optimal tracers. Results Recently, we introduced a new framework for optimal 13C-tracer design based on elementary metabolite units (EMU) decomposition, in which a measured metabolite is decomposed into a linear combination of so-called EMU basis vectors. In this contribution, we applied the EMU method to a realistic network model of mammalian metabolism with lactate as the measured metabolite. The method was used to select optimal tracers for two free fluxes in the system, the oxidative pentose phosphate pathway (oxPPP) flux and anaplerosis by pyruvate carboxylase (PC). Our approach was based on sensitivity analysis of EMU basis vector coefficients with respect to free fluxes. Through efficient grouping of coefficient sensitivities, simple tracer selection rules were derived for high-resolution quantification of the fluxes in the mammalian network model. The approach resulted in a significant reduction of the number of possible tracers and the feasible tracers were evaluated using numerical simulations. Two optimal, novel tracers were identified that have not been previously considered for 13C-MFA of mammalian cells, specifically [2,3,4,5,6-13C]glucose for elucidating oxPPP flux and [3,4-13C]glucose for elucidating PC flux. We demonstrate that 13C-glutamine tracers perform poorly in this system in comparison to the optimal glucose tracers. Conclusions In this work, we have demonstrated that optimal tracer design does not need to be a pure simulation-based trial-and-error process; rather, rational insights into tracer design can be gained through the application of the EMU basis vector methodology. Using this approach, rational labeling rules can be established a priori to guide the selection of optimal 13C-tracers for high-resolution flux elucidation in complex metabolic network models.
Collapse
Affiliation(s)
- Scott B Crown
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, Newark, DE 19716, USA
| | | | | |
Collapse
|
17
|
Klein S, Heinzle E. Isotope labeling experiments in metabolomics and fluxomics. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2012; 4:261-72. [DOI: 10.1002/wsbm.1167] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
18
|
Crown SB, Antoniewicz MR. Selection of tracers for 13C-metabolic flux analysis using elementary metabolite units (EMU) basis vector methodology. Metab Eng 2011; 14:150-61. [PMID: 22209989 DOI: 10.1016/j.ymben.2011.12.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 12/06/2011] [Accepted: 12/13/2011] [Indexed: 12/22/2022]
Abstract
Metabolic flux analysis (MFA) is a powerful technique for elucidating in vivo fluxes in microbial and mammalian systems. A key step in (13)C-MFA is the selection of an appropriate isotopic tracer to observe fluxes in a proposed network model. Despite the importance of MFA in metabolic engineering and beyond, current approaches for tracer experiment design are still largely based on trial-and-error. The lack of a rational methodology for selecting isotopic tracers prevents MFA from achieving its full potential. Here, we introduce a new technique for tracer experiment design based on the concept of elementary metabolite unit (EMU) basis vectors. We demonstrate that any metabolite in a network model can be expressed as a linear combination of so-called EMU basis vectors, where the corresponding coefficients indicate the fractional contribution of the EMU basis vector to the product metabolite. The strength of this approach is the decoupling of substrate labeling, i.e. the EMU basis vectors, from the dependence on free fluxes, i.e. the coefficients. In this work, we demonstrate that flux observability inherently depends on the number of independent EMU basis vectors and the sensitivities of coefficients with respect to free fluxes. Specifically, the number of independent EMU basis vectors places hard limits on how many free fluxes can be determined in a model. This constraint is used as a guide for selecting feasible substrate labeling. In three example models, we demonstrate that by maximizing the number of independent EMU basis vectors the observability of a system is improved. Inspection of sensitivities of coefficients with respect to free fluxes provides additional constraints for proper selection of tracers. The present contribution provides a fresh perspective on an important topic in metabolic engineering, and gives practical guidelines and design principles for a priori selection of isotopic tracers for (13)C-MFA studies.
Collapse
Affiliation(s)
- Scott B Crown
- Department of Chemical Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, 150 Academy St., Newark, DE 19716, USA
| | | |
Collapse
|
19
|
Peacock AD, Hedrick DB, Long PE, Nevin KP, Resch CT, Lovley DR, White DC. Field-scale uranium (VI) bioimmobilization monitored by lipid biomarkers and 13C-acetate incorporation. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/rem.20301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
20
|
Tandem mass spectrometry: A novel approach for metabolic flux analysis. Metab Eng 2011; 13:225-33. [DOI: 10.1016/j.ymben.2010.11.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 10/17/2010] [Accepted: 11/23/2010] [Indexed: 11/20/2022]
|
21
|
Terzer M, Maynard ND, Covert MW, Stelling J. Genome-scale metabolic networks. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2011; 1:285-297. [PMID: 20835998 DOI: 10.1002/wsbm.37] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
During the last decade, models have been developed to characterize cellular metabolism at the level of an entire metabolic network. The main concept that underlies whole-network metabolic modeling is the identification and mathematical definition of constraints. Here, we review large-scale metabolic network modeling, in particular, stoichiometric- and constraint-based approaches. Although many such models have been reconstructed, few networks have been extensively validated and tested experimentally, and we focus on these. We describe how metabolic networks can be represented using stoichiometric matrices and well-defined constraints on metabolic fluxes. We then discuss relatively successful approaches, including flux balance analysis (FBA), pathway analysis, and common extensions or modifications to these approaches. Finally, we describe techniques for integrating these approaches with models of other biological processes.
Collapse
Affiliation(s)
- Marco Terzer
- Department of Biosystems Science and Engineering, ETH Zurich, Switzerland
| | | | - Markus W Covert
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Jörg Stelling
- Department of Biosystems Science and Engineering, ETH Zurich, Switzerland
| |
Collapse
|
22
|
van Ommen B, El-Sohemy A, Hesketh J, Kaput J, Fenech M, Evelo CT, McArdle HJ, Bouwman J, Lietz G, Mathers JC, Fairweather-Tait S, van Kranen H, Elliott R, Wopereis S, Ferguson LR, Méplan C, Perozzi G, Allen L, Rivero D. The Micronutrient Genomics Project: a community-driven knowledge base for micronutrient research. GENES AND NUTRITION 2010; 5:285-96. [PMID: 21189865 PMCID: PMC2989004 DOI: 10.1007/s12263-010-0192-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2010] [Accepted: 10/13/2010] [Indexed: 01/19/2023]
Abstract
Micronutrients influence multiple metabolic pathways including oxidative and inflammatory processes. Optimum micronutrient supply is important for the maintenance of homeostasis in metabolism and, ultimately, for maintaining good health. With advances in systems biology and genomics technologies, it is becoming feasible to assess the activity of single and multiple micronutrients in their complete biological context. Existing research collects fragments of information, which are not stored systematically and are thus not optimally disseminated. The Micronutrient Genomics Project (MGP) was established as a community-driven project to facilitate the development of systematic capture, storage, management, analyses, and dissemination of data and knowledge generated by biological studies focused on micronutrient–genome interactions. Specifically, the MGP creates a public portal and open-source bioinformatics toolbox for all “omics” information and evaluation of micronutrient and health studies. The core of the project focuses on access to, and visualization of, genetic/genomic, transcriptomic, proteomic and metabolomic information related to micronutrients. For each micronutrient, an expert group is or will be established combining the various relevant areas (including genetics, nutrition, biochemistry, and epidemiology). Each expert group will (1) collect all available knowledge, (2) collaborate with bioinformatics teams towards constructing the pathways and biological networks, and (3) publish their findings on a regular basis. The project is coordinated in a transparent manner, regular meetings are organized and dissemination is arranged through tools, a toolbox web portal, a communications website and dedicated publications.
Collapse
Affiliation(s)
- Ben van Ommen
- TNO Quality of Life, P.O. box 360, 3700 AJ Zeist, The Netherlands
| | - Ahmed El-Sohemy
- Department of Nutritional Sciences, University of Toronto, 150 College Street, Toronto, ON M5S 3E2 Canada
| | - John Hesketh
- Institute for Cell and Molecular Biosciences, Newcastle University Medical School and Human Nutrition Research Centre, Newcastle-upon-Tyne, NE2 4HH UK
| | - Jim Kaput
- Division of Personalized Nutrition and Medicine, National Center for Toxicological Research, Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079 USA
| | - Michael Fenech
- CSIRO Food and Nutritional Sciences, PO Box 10041, Adelaide BC, SA 5000 Australia
| | - Chris T. Evelo
- Department of Bioinformatics—BiGCaT, Maastricht University, Maastricht, The Netherlands
| | - Harry J. McArdle
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, AB21 9SB UK
| | - Jildau Bouwman
- TNO Quality of Life, P.O. box 360, 3700 AJ Zeist, The Netherlands
| | - Georg Lietz
- Human Nutrition Research Centre, School of Agriculture, Food and Rural Development, Newcastle University, Kings Road, Agriculture Building, Newcastle upon Tyne, NE1 7RU UK
| | - John C. Mathers
- Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, NE2 4HH UK
| | - Sue Fairweather-Tait
- School of Medicine, Health Policy and Practice, University of East Anglia, Norwich, NR4 7TJ UK
| | | | - Ruan Elliott
- Institute of Food Research, Norwich Research Park, Norwich, NR4 7UA UK
| | - Suzan Wopereis
- TNO Quality of Life, P.O. box 360, 3700 AJ Zeist, The Netherlands
| | - Lynnette R. Ferguson
- Discipline of Nutrition, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Catherine Méplan
- Institute for Cell and Molecular Biosciences, Newcastle University Medical School and Human Nutrition Research Centre, Newcastle-upon-Tyne, NE2 4HH UK
| | - Giuditta Perozzi
- Department of Nutritional Sciences—INRAN, National Research Institute on Food & Nutrition, Via Ardeatina 546, 00178 Rome, Italy
| | - Lindsay Allen
- USDA, ARS Western Human Nutrition Research Center, University of California, 530 W. Health Sciences Drive, Davis, CA 95616 USA
| | - Damariz Rivero
- Department of Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy
| | | |
Collapse
|
23
|
Abstract
Stable isotope, and in particular (13)C-based flux analysis, is the exclusive approach to experimentally quantify the integrated responses of metabolic networks. Here we describe a protocol that is based on growing microbes on (13)C-labeled glucose and subsequent gas chromatography mass spectrometric detection of (13)C-patterns in protein-bound amino acids. Relying on publicly available software packages, we then describe two complementary mathematical approaches to estimate either local ratios of converging fluxes or absolute fluxes through different pathways. As amino acids in cell protein are abundant and stable, this protocol requires a minimum of equipment and analytical expertise. Most other flux methods are variants of the principles presented here. A true alternative is the analytically more demanding dynamic flux analysis that relies on (13)C-pattern in free intracellular metabolites. The presented protocols take 5-10 d, have been used extensively in the past decade and are exemplified here for the central metabolism of Escherichia coli.
Collapse
Affiliation(s)
- Nicola Zamboni
- Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
| | | | | | | |
Collapse
|
24
|
Quek LE, Wittmann C, Nielsen LK, Krömer JO. OpenFLUX: efficient modelling software for 13C-based metabolic flux analysis. Microb Cell Fact 2009; 8:25. [PMID: 19409084 PMCID: PMC2689189 DOI: 10.1186/1475-2859-8-25] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Accepted: 05/01/2009] [Indexed: 11/30/2022] Open
Abstract
Background The quantitative analysis of metabolic fluxes, i.e., in vivo activities of intracellular enzymes and pathways, provides key information on biological systems in systems biology and metabolic engineering. It is based on a comprehensive approach combining (i) tracer cultivation on 13C substrates, (ii) 13C labelling analysis by mass spectrometry and (iii) mathematical modelling for experimental design, data processing, flux calculation and statistics. Whereas the cultivation and the analytical part is fairly advanced, a lack of appropriate modelling software solutions for all modelling aspects in flux studies is limiting the application of metabolic flux analysis. Results We have developed OpenFLUX as a user friendly, yet flexible software application for small and large scale 13C metabolic flux analysis. The application is based on the new Elementary Metabolite Unit (EMU) framework, significantly enhancing computation speed for flux calculation. From simple notation of metabolic reaction networks defined in a spreadsheet, the OpenFLUX parser automatically generates MATLAB-readable metabolite and isotopomer balances, thus strongly facilitating model creation. The model can be used to perform experimental design, parameter estimation and sensitivity analysis either using the built-in gradient-based search or Monte Carlo algorithms or in user-defined algorithms. Exemplified for a microbial flux study with 71 reactions, 8 free flux parameters and mass isotopomer distribution of 10 metabolites, OpenFLUX allowed to automatically compile the EMU-based model from an Excel file containing metabolic reactions and carbon transfer mechanisms, showing it's user-friendliness. It reliably reproduced the published data and optimum flux distributions for the network under study were found quickly (<20 sec). Conclusion We have developed a fast, accurate application to perform steady-state 13C metabolic flux analysis. OpenFLUX will strongly facilitate and enhance the design, calculation and interpretation of metabolic flux studies. By providing the software open source, we hope it will evolve with the rapidly growing field of fluxomics.
Collapse
Affiliation(s)
- Lake-Ee Quek
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, QLD 4072, Australia.
| | | | | | | |
Collapse
|
25
|
Alvarez-Vasquez F, Hannun YA, Voit EO. Dynamics of Positional Enrichment: Theoretical Development and Application to Carbon Labeling in Zymomonas mobilis. Biochem Eng J 2008; 40:157-174. [PMID: 19412323 DOI: 10.1016/j.bej.2007.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Positional enrichment analysis has become an important technique for assessing detailed flux distributions and the fates of specific atoms in metabolic pathway systems. The typical approach to positional enrichment analysis is performed by supplying specifically labeled substrate to a cell system, letting the system reach steady state, and measuring where label had arrived and accumulated. The data are then evaluated mathematically with the help of a linear stoichiometric flux distribution model. While this procedure has proven to yield new and valuable insights, it does not address the transient dynamics between providing label and its ultimate steady-state distribution, which is often of great interest to the experimentalist (pulse labeling experiments). We show here that an extension of a recent mathematical method for dynamic labeling analysis is able to shed light on these transitions, thereby revealing insights not obtained with traditional positional enrichment analyses. The method traces the dynamics of one or more carbons through fully regulated metabolic pathways, which, in principle, may be arbitrarily complex. After a brief review of the earlier method and description of the theoretical extension, we illustrate the method with an analysis of the pentose phosphate pathway in Zymomonas mobilis, which has been used for traditional positional enrichment analyses in the past. We show how different labeling schemes result in distinctly different transients, which nevertheless eventually lead to a steady-state labeling profile that coincides exactly with the corresponding profile from traditional analysis. Thus, over the domain of commonality, the proposed method leads to results equivalent to those from state-of-the-art existing methods. However, these steady-state results constitute only a small portion of the insights obtainable with the proposed method. Our method can also be used as an "inverse" technique for elucidating the topology and regulation of pathway systems, if appropriate time series data are available. While such dynamic data are still rather rare, they are now being generated with increasing frequency and we believe it is desirable, and indeed necessary, to accompany this trend with an adequate, rigorous method of analysis.
Collapse
Affiliation(s)
- Fernando Alvarez-Vasquez
- Dept. of Biostatistics, Bioinformatics and Epidemiology. Medical University of South Carolina, Charleston, SC. USA
| | | | | |
Collapse
|
26
|
Weitzel M, Wiechert W, Nöh K. The topology of metabolic isotope labeling networks. BMC Bioinformatics 2007; 8:315. [PMID: 17727715 PMCID: PMC2233644 DOI: 10.1186/1471-2105-8-315] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Accepted: 08/29/2007] [Indexed: 11/23/2022] Open
Abstract
Background Metabolic Flux Analysis (MFA) based on isotope labeling experiments (ILEs) is a widely established tool for determining fluxes in metabolic pathways. Isotope labeling networks (ILNs) contain all essential information required to describe the flow of labeled material in an ILE. Whereas recent experimental progress paves the way for high-throughput MFA, large network investigations and exact statistical methods, these developments are still limited by the poor performance of computational routines used for the evaluation and design of ILEs. In this context, the global analysis of ILN topology turns out to be a clue for realizing large speedup factors in all required computational procedures. Results With a strong focus on the speedup of algorithms the topology of ILNs is investigated using graph theoretic concepts and algorithms. A rigorous determination of all cyclic and isomorphic subnetworks, accompanied by the global analysis of ILN connectivity is performed. Particularly, it is proven that ILNs always brake up into a large number of small strongly connected components (SCCs) and, moreover, there are natural isomorphisms between many of these SCCs. All presented techniques are universal, i.e. they do not require special assumptions on the network structure, bidirectionality of fluxes, measurement configuration, or label input. The general results are exemplified with a practically relevant metabolic network which describes the central metabolism of E. coli comprising 10390 isotopomer pools. Conclusion Exploiting the topological features of ILNs leads to a significant speedup of all universal algorithms for ILE evaluation. It is proven in theory and exemplified with the E. coli example that a speedup factor of about 1000 compared to standard algorithms is achieved. This widely opens the door for new high performance algorithms suitable for high throughput applications and large ILNs. Moreover, for the first time the global topological analysis of ILNs allows to comprehensively describe and understand the general patterns of label flow in complex networks. This is an invaluable tool for the structural design of new experiments and the interpretation of measured data.
Collapse
Affiliation(s)
- Michael Weitzel
- Department of Simulation, University of Siegen, 57068 Siegen, Germany
| | - Wolfgang Wiechert
- Department of Simulation, University of Siegen, 57068 Siegen, Germany
| | - Katharina Nöh
- Institute of Biotechnology, Research Centre Jülich, 52425 Jülich, Germany
| |
Collapse
|
27
|
Abstract
Fluxome analysis aims at the quantitative analysis of in vivo carbon fluxes in metabolic networks, i. e. intracellular activities of enzymes and pathways. It allows investigating the effects of genetic or environmental modifications and thus precisely provides a global perspective on the integrated genetic and metabolic regulation within the intact metabolic network. The experimental and computational approaches developed in this area have revealed fascinating insights into metabolic properties of various biological systems. Most of the comprehensive approaches for metabolic flux studies today involve isotopic tracer studies and GC-MS for measurement of the labeling pattern of metabolites. Initially developed and applied mainly in the field of biomedicine these GC-MS based metabolic flux approaches have been substantially extended and optimized during recent years and today display a key technology in metabolic physiology and biotechnology.
Collapse
Affiliation(s)
- Christoph Wittmann
- Biochemical Engineering Institute, Saarland University, Saarbrücken, Germany.
| |
Collapse
|
28
|
Frick O, Wittmann C. Characterization of the metabolic shift between oxidative and fermentative growth in Saccharomyces cerevisiae by comparative 13C flux analysis. Microb Cell Fact 2005; 4:30. [PMID: 16269086 PMCID: PMC1291395 DOI: 10.1186/1475-2859-4-30] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Accepted: 11/03/2005] [Indexed: 11/16/2022] Open
Abstract
Background One of the most fascinating properties of the biotechnologically important organism Saccharomyces cerevisiae is its ability to perform simultaneous respiration and fermentation at high growth rate even under fully aerobic conditions. In the present work, this Crabtree effect called phenomenon was investigated in detail by comparative 13C metabolic flux analysis of S. cerevisiae growing under purely oxidative, respiro-fermentative and predominantly fermentative conditions. Results The metabolic shift from oxidative to fermentative growth was accompanied by complex changes of carbon flux throughout the whole central metabolism. This involved a flux redirection from the pentose phosphate pathway (PPP) towards glycolysis, an increased flux through pyruvate carboxylase, the fermentative pathways and malic enzyme, a flux decrease through the TCA cycle, and a partial relocation of alanine biosynthesis from the mitochondrion to the cytosol. S. cerevisiae exhibited a by-pass of pyruvate dehydrogenase in all physiological regimes. During oxidative growth this by-pass was mainly provided via pyruvate decarboxylase, acetaldehyde dehydrogenase, acetyl-CoA synthase and transport of acetyl-CoA into the mitochondrion. During fermentative growth this route, however, was saturated due to limited enzyme capacity. Under these conditions the cells exhibited high carbon flux through a chain of reactions involving pyruvate carboxylase, the oxaloacetate transporter and malic enzyme. During purely oxidative growth the PPP alone was sufficient to completely supply NADPH for anabolism. During fermentation, it provided only 60 % of the required NADPH. Conclusion We conclude that, in order to overcome the limited capacity of pyruvate dehydrogenase, S. cerevisiae possesses different metabolic by-passes to channel carbon into the mitochondrion. This involves the conversion of cytosolic pyruvate either into acetyl CoA or oxaloacetate followed by intercompartmental transport of these metabolites. During oxidative growth mainly the NAD specific isoforms of acetaldehyde dehydrogenase and isocitrate dehydrogenase catalyze the corresponding reactions in S. cerevisiae, whereas NADPH supply under fermentative conditions involves significant contribution of sources other than the PPP such as e. g. NADPH specific acetaldehyde dehydrogenase or isocitrate dehydrogenase.
Collapse
Affiliation(s)
- Oliver Frick
- Biochemical Engineering Institute, Saarland University, POB 151150, 66123 Saarbrücken, Germany
| | - Christoph Wittmann
- Biochemical Engineering Institute, Saarland University, POB 151150, 66123 Saarbrücken, Germany
| |
Collapse
|
29
|
Zamboni N, Fischer E, Laudert D, Aymerich S, Hohmann HP, Sauer U. The Bacillus subtilis yqjI gene encodes the NADP+-dependent 6-P-gluconate dehydrogenase in the pentose phosphate pathway. J Bacteriol 2004; 186:4528-34. [PMID: 15231785 PMCID: PMC438568 DOI: 10.1128/jb.186.14.4528-4534.2004] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Despite the importance of the oxidative pentose phosphate (PP) pathway as a major source of reducing power and metabolic intermediates for biosynthetic processes, almost no direct genetic or biochemical evidence is available for Bacillus subtilis. Using a combination of knockout mutations in known and putative genes of the oxidative PP pathway and 13C-labeling experiments, we demonstrated that yqjI encodes the NADP+-dependent 6-P-gluconate dehydrogenase, as was hypothesized previously from sequence similarities. Moreover, YqjI was the predominant isoenzyme during glucose and gluconate catabolism, and its role in the oxidative PP pathway could not be played by either of two homologues, GntZ and YqeC. This conclusion is in contrast to the generally held view that GntZ is the relevant isoform; hence, we propose a new designation for yqjI, gndA, the monocistronic gene encoding the principal 6-P-gluconate dehydrogenase. Although we demonstrated the NAD+-dependent 6-P-gluconate dehydrogenase activity of GntZ, gntZ mutants exhibited no detectable phenotype on glucose, and GntZ did not contribute to PP pathway fluxes during growth on glucose. Since gntZ mutants grew normally on gluconate, the functional role of GntZ remains obscure, as does the role of the third homologue, YqeC. Knockout of the glucose-6-P dehydrogenase-encoding zwf gene was primarily compensated for by increased glycolytic fluxes, but about 5% of the catabolic flux was rerouted through the gluconate bypass with glucose dehydrogenase as the key enzyme.
Collapse
Affiliation(s)
- Nicola Zamboni
- Institute of Biotechnology, ETH Zürich, Zürich, Switzerland
| | | | | | | | | | | |
Collapse
|
30
|
Krömer JO, Sorgenfrei O, Klopprogge K, Heinzle E, Wittmann C. In-depth profiling of lysine-producing Corynebacterium glutamicum by combined analysis of the transcriptome, metabolome, and fluxome. J Bacteriol 2004; 186:1769-84. [PMID: 14996808 PMCID: PMC355958 DOI: 10.1128/jb.186.6.1769-1784.2004] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An in-depth analysis of the intracellular metabolite concentrations, metabolic fluxes, and gene expression (metabolome, fluxome, and transcriptome, respectively) of lysine-producing Corynebacterium glutamicum ATCC 13287 was performed at different stages of batch culture and revealed distinct phases of growth and lysine production. For this purpose, 13C flux analysis with gas chromatography-mass spectrometry-labeling measurement of free intracellular amino acids, metabolite balancing, and isotopomer modeling were combined with expression profiling via DNA microarrays and with intracellular metabolite quantification. The phase shift from growth to lysine production was accompanied by a decrease in glucose uptake flux, the redirection of flux from the tricarboxylic acid (TCA) cycle towards anaplerotic carboxylation and lysine biosynthesis, transient dynamics of intracellular metabolite pools, such as an increase of lysine up to 40 mM prior to its excretion, and complex changes in the expression of genes for central metabolism. The integrated approach was valuable for the identification of correlations between gene expression and in vivo activity for numerous enzymes. The glucose uptake flux closely corresponded to the expression of glucose phosphotransferase genes. A correlation between flux and expression was also observed for glucose-6-phosphate dehydrogenase, transaldolase, and transketolase and for most TCA cycle genes. In contrast, cytoplasmic malate dehydrogenase expression increased despite a reduction of the TCA cycle flux, probably related to its contribution to NADH regeneration under conditions of reduced growth. Most genes for lysine biosynthesis showed a constant expression level, despite a marked change of the metabolic flux, indicating that they are strongly regulated at the metabolic level. Glyoxylate cycle genes were continuously expressed, but the pathway exhibited in vivo activity only in the later stage. The most pronounced changes in gene expression during cultivation were found for enzymes at entry points into glycolysis, the pentose phosphate pathway, the TCA cycle, and lysine biosynthesis, indicating that these might be of special importance for transcriptional control in C. glutamicum.
Collapse
Affiliation(s)
- Jens Olaf Krömer
- Biochemical Engineering, Saarland University, Saarbrücken, Germany
| | | | | | | | | |
Collapse
|
31
|
Wittmann C, Heinzle E. Genealogy profiling through strain improvement by using metabolic network analysis: metabolic flux genealogy of several generations of lysine-producing corynebacteria. Appl Environ Microbiol 2002; 68:5843-59. [PMID: 12450803 PMCID: PMC134428 DOI: 10.1128/aem.68.12.5843-5859.2002] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A comprehensive approach of metabolite balancing, (13)C tracer studies, gas chromatography-mass spectrometry, matrix-assisted laser desorption ionization-time of flight mass spectrometry, and isotopomer modeling was applied for comparative metabolic network analysis of a genealogy of five successive generations of lysine-producing Corynebacterium glutamicum. The five strains examined (C. glutamicum ATCC 13032, 13287, 21253, 21526, and 21543) were previously obtained by random mutagenesis and selection. Throughout the genealogy, the lysine yield in batch cultures increased markedly from 1.2 to 24.9% relative to the glucose uptake flux. Strain optimization was accompanied by significant changes in intracellular flux distributions. The relative pentose phosphate pathway (PPP) flux successively increased, clearly corresponding to the product yield. Moreover, the anaplerotic net flux increased almost twofold as a consequence of concerted regulation of C(3) carboxylation and C(4) decarboxylation fluxes to cover the increased demand for lysine formation; thus, the overall increase was a consequence of concerted regulation of C(3) carboxylation and C(4) decarboxylation fluxes. The relative flux through isocitrate dehydrogenase dropped from 82.7% in the wild type to 59.9% in the lysine-producing mutants. In contrast to the NADPH demand, which increased from 109 to 172% due to the increasing lysine yield, the overall NADPH supply remained constant between 185 and 196%, resulting in a decrease in the apparent NADPH excess through strain optimization. Extrapolated to industrial lysine producers, the NADPH supply might become a limiting factor. The relative contributions of PPP and the tricarboxylic acid cycle to NADPH generation changed markedly, indicating that C. glutamicum is able to maintain a constant supply of NADPH under completely different flux conditions. Statistical analysis by a Monte Carlo approach revealed high precision for the estimated fluxes, underlining the fact that the observed differences were clearly strain specific.
Collapse
Affiliation(s)
- Christoph Wittmann
- Biochemical Engineering Institute, Saarland University, Saarbruecken, Germany.
| | | |
Collapse
|
32
|
Abstract
Metabolic flux analysis using 13C-labeled substrates has become an important tool in metabolic engineering. It allows the detailed quantification of all intracellular fluxes in the central metabolism of a microorganism. The method has strongly evolved in recent years by the introduction of new experimental procedures, measurement techniques, and mathematical data evaluation methods. Many of these improvements require advanced skills in the application of nuclear magnetic resonance and mass spectrometry techniques on the one hand and computational and statistical experience on the other hand. This minireview summarizes these recent developments and sketches the major practical problems. An outlook to possible future developments concludes the text.
Collapse
Affiliation(s)
- W Wiechert
- Department of Simulation, IMR, University of Siegen, Paul-Bonatz-Strasse 9-11, D-57068 Siegen, Germany.
| |
Collapse
|