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Umamaheswaran R, Dutta S, Khan MA, Bera M, Bera S, Kumar S. Identification of Chitin in Pliocene Fungi Using Py-GC × GC-TOFMS: Potential Implications for the Study of the Evolution of the Fungal Clade in Deep Time. Anal Chem 2022; 94:1958-1964. [PMID: 35037459 DOI: 10.1021/acs.analchem.1c03143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular dating estimates the origin of the fungal clade to the Pre-Cambrian. Yet, the oldest unambiguous fungal fossils date to the Ordovician and show remarkable diversity and organizational development. Recent studies have suggested that the dates for the emergence of fungi in the fossil record may be pushed back to the Proterozoic. However, the nonspecificity of the methods used in those studies necessitates the employment of a wider variety of analytical techniques that can independently verify the presence of chitin, a crucial prerequisite in the assignment of fungal affinity, particularly of putative fossils from the Pre-Cambrian. In this paper, we propose Py-GC × GC-TOFMS as an example of one such technique. We analyze fungal fossils from the Pliocene. We find that a suite of N-bearing compounds are present in the pyrolysis products of these fossils, from which we suggest that 3-acetamidopyrones and their methylated homologues can serve as specific pyrolytic markers for chitin. We discuss both how this technique can potentially be used to differentiate between biopolymers, including those similar to chitin such as peptidoglycan, and the potential implications of identifying such markers in fossils from deep time. We conclude that Py-GC × GC-TOFMS is a promising technique that can potentially be used alongside, or independent of, staining methods to detect the presence of chitin in fossils.
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Affiliation(s)
- Raman Umamaheswaran
- Department of Earth Sciences, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Suryendu Dutta
- Department of Earth Sciences, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Mahasin Ali Khan
- Department of Botany, Siddho-Kanho-Birsa University, Puruliya 723149, India
| | - Meghma Bera
- Department of Botany, Vidyanagar College, Vidyanagar 743503, India
| | - Subir Bera
- Department of Botany, University of Calcutta, Kolkata 700019, India
| | - Sumit Kumar
- Department of Earth Sciences, Indian Institute of Technology Bombay, Mumbai 400076, India
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Lellman SE, Cramer R. Bacterial identification by lipid profiling using liquid atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry. ACTA ACUST UNITED AC 2019; 58:930-938. [DOI: 10.1515/cclm-2019-0908] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/25/2019] [Indexed: 12/16/2022]
Abstract
Abstract
Background
In recent years, mass spectrometry (MS) has been applied to clinical microbial biotyping, exploiting the speed of matrix-assisted laser desorption/ionization (MALDI) in recording microbe-specific MS profiles. More recently, liquid atmospheric pressure (AP) MALDI has been shown to produce extremely stable ion flux from homogenous samples and ‘electrospray ionization (ESI)-like’ multiply charged ions for larger biomolecules, whilst maintaining the benefits of traditional MALDI including high tolerance to contaminants, low analyte consumption and rapid analysis. These and other advantages of liquid AP-MALDI MS have been explored in this study to investigate its potential in microbial biotyping.
Methods
Genetically diverse bacterial strains were analyzed using liquid AP-MALDI MS, including clinically relevant species such as Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae. Bacterial cultures were subjected to a simple and fast extraction protocol using ethanol and formic acid. Extracts were spotted with a liquid support matrix (LSM) and analyzed using a Synapt G2-Si mass spectrometer with an in-house built AP-MALDI source.
Results
Each species produces a unique lipid profile in the m/z range of 400–1100, allowing species discrimination. Traditional (solid) MALDI MS produced spectra containing a high abundance of matrix-related clusters and an absence of lipid peaks. The MS profiles of the bacterial species tested form distinct clusters using principle component analysis (PCA) with a classification accuracy of 98.63% using a PCA-based prediction model.
Conclusions
Liquid AP-MALDI MS profiles can be sufficient to distinguish clinically relevant bacterial pathogens and other bacteria, based on their unique lipid profiles. The analysis of the lipid MS profiles is typically excluded from commercial instruments approved for clinical diagnostics.
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Affiliation(s)
- Sophie E. Lellman
- Department of Chemistry , University of Reading , Whiteknights, Reading , UK
| | - Rainer Cramer
- Department of Chemistry , University of Reading , Whiteknights, Reading , UK
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3
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Franco-Duarte R, Černáková L, Kadam S, Kaushik KS, Salehi B, Bevilacqua A, Corbo MR, Antolak H, Dybka-Stępień K, Leszczewicz M, Relison Tintino S, Alexandrino de Souza VC, Sharifi-Rad J, Coutinho HDM, Martins N, Rodrigues CF. Advances in Chemical and Biological Methods to Identify Microorganisms-From Past to Present. Microorganisms 2019; 7:E130. [PMID: 31086084 PMCID: PMC6560418 DOI: 10.3390/microorganisms7050130] [Citation(s) in RCA: 157] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 04/30/2019] [Accepted: 05/08/2019] [Indexed: 12/12/2022] Open
Abstract
Fast detection and identification of microorganisms is a challenging and significant feature from industry to medicine. Standard approaches are known to be very time-consuming and labor-intensive (e.g., culture media and biochemical tests). Conversely, screening techniques demand a quick and low-cost grouping of bacterial/fungal isolates and current analysis call for broad reports of microorganisms, involving the application of molecular techniques (e.g., 16S ribosomal RNA gene sequencing based on polymerase chain reaction). The goal of this review is to present the past and the present methods of detection and identification of microorganisms, and to discuss their advantages and their limitations.
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Affiliation(s)
- Ricardo Franco-Duarte
- CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, 4710-057 Braga, Portugal.
- Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, 4710-057 Braga, Portugal.
| | - Lucia Černáková
- Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15 Bratislava, Slovakia.
| | - Snehal Kadam
- Ramalingaswami Re-entry Fellowship, Department of Biotechnology, Government of India, India.
| | - Karishma S Kaushik
- Ramalingaswami Re-entry Fellowship, Department of Biotechnology, Government of India, India.
| | - Bahare Salehi
- Student Research Committee, School of Medicine, Bam University of Medical Sciences, Bam 14665-354, Iran.
| | - Antonio Bevilacqua
- Department of the Science of Agriculture, Food and Environment, University of Foggia, 71121 Foggia, Italy.
| | - Maria Rosaria Corbo
- Department of the Science of Agriculture, Food and Environment, University of Foggia, 71121 Foggia, Italy.
| | - Hubert Antolak
- Institute of Fermentation Technology and Microbiology, Department of Biotechnology and Food Science, Lodz University of Technology, Wolczanska 171/173, 90-924 Lodz, Poland.
| | - Katarzyna Dybka-Stępień
- Institute of Fermentation Technology and Microbiology, Department of Biotechnology and Food Science, Lodz University of Technology, Wolczanska 171/173, 90-924 Lodz, Poland.
| | - Martyna Leszczewicz
- Laboratory of Industrial Biotechnology, Bionanopark Ltd, Dubois 114/116, 93-465 Lodz, Poland.
| | - Saulo Relison Tintino
- Laboratory of Microbiology and Molecular Biology (LMBM), Department of Biological Chemistry/CCBS/URCA, 63105-000 Crato, Brazil.
| | | | - Javad Sharifi-Rad
- Zabol Medicinal Plants Research Center, Zabol University of Medical Sciences, Zabol 61615-585, Iran.
| | - Henrique Douglas Melo Coutinho
- Laboratory of Microbiology and Molecular Biology (LMBM), Department of Biological Chemistry/CCBS/URCA, 63105-000 Crato, Brazil.
| | - Natália Martins
- Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal.
- Institute for Research and Innovation in Health (i3S), University of Porto, 4200-135 Porto, Portugal.
| | - Célia F Rodrigues
- LEPABE⁻Dep. of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.
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Beverly MB, Basile F, Voorhees KJ. Fatty Acid Analysis of Beer Spoiling Microorganisms Using Pyrolysis Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY OF BREWING CHEMISTS 2018. [DOI: 10.1094/asbcj-55-0079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Michael B. Beverly
- Chemistry and Geochemistry Department, Colorado School of Mines, Golden CO 80401
| | - Franco Basile
- Chemistry and Geochemistry Department, Colorado School of Mines, Golden CO 80401
| | - Kent J. Voorhees
- Chemistry and Geochemistry Department, Colorado School of Mines, Golden CO 80401
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Brignardello J, Holmes E, Garcia-Perez I. Metabolic Phenotyping of Diet and Dietary Intake. ADVANCES IN FOOD AND NUTRITION RESEARCH 2017; 81:231-270. [PMID: 28317606 DOI: 10.1016/bs.afnr.2016.12.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nutrition provides the building blocks for growth, repair, and maintenance of the body and is key to maintaining health. Exposure to fast foods, mass production of dietary components, and wider importation of goods have challenged the balance between diet and health in recent decades, and both scientists and clinicians struggle to characterize the relationship between this changing dietary landscape and human metabolism with its consequent impact on health. Metabolic phenotyping of foods, using high-density data-generating technologies to profile the biochemical composition of foods, meals, and human samples (pre- and postfood intake), can be used to map the complex interaction between the diet and human metabolism and also to assess food quality and safety. Here, we outline some of the techniques currently used for metabolic phenotyping and describe key applications in the food sciences, ending with a broad outlook at some of the newer technologies in the field with a view to exploring their potential to address some of the critical challenges in nutritional science.
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Affiliation(s)
- J Brignardello
- Computational and Systems Medicine, Imperial College London, London, United Kingdom
| | - E Holmes
- Computational and Systems Medicine, Imperial College London, London, United Kingdom
| | - I Garcia-Perez
- Nutrition and Dietetic Research Group, Imperial College London, London, United Kingdom.
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Bolt F, Cameron SJS, Karancsi T, Simon D, Schaffer R, Rickards T, Hardiman K, Burke A, Bodai Z, Perdones-Montero A, Rebec M, Balog J, Takats Z. Automated High-Throughput Identification and Characterization of Clinically Important Bacteria and Fungi using Rapid Evaporative Ionization Mass Spectrometry. Anal Chem 2016; 88:9419-9426. [DOI: 10.1021/acs.analchem.6b01016] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Frances Bolt
- Section
of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Simon J. S. Cameron
- Section
of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Tamas Karancsi
- Waters Research
Centre, 7 Zahony Street, Budapest, 1031, Hungary
| | - Daniel Simon
- Waters Research
Centre, 7 Zahony Street, Budapest, 1031, Hungary
| | - Richard Schaffer
- Waters Research
Centre, 7 Zahony Street, Budapest, 1031, Hungary
| | - Tony Rickards
- Department
of Microbiology, Imperial College Healthcare NHS Trust, Charing Cross
Hospital, London W6 8RF, United Kingdom
| | - Kate Hardiman
- Section
of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Adam Burke
- Section
of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Zsolt Bodai
- Section
of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Alvaro Perdones-Montero
- Section
of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Monica Rebec
- Department
of Microbiology, Imperial College Healthcare NHS Trust, Charing Cross
Hospital, London W6 8RF, United Kingdom
| | - Julia Balog
- Waters Research
Centre, 7 Zahony Street, Budapest, 1031, Hungary
| | - Zoltan Takats
- Section
of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, SW7 2AZ, United Kingdom
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7
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Alusta P, Buzatu D, Williams A, Cooper WM, Tarasenko O, Dorey RC, Hall R, Parker WR, Wilkes JG. Instrumental improvements and sample preparations that enable reproducible, reliable acquisition of mass spectra from whole bacterial cells. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:1961-1968. [PMID: 26443394 PMCID: PMC4600233 DOI: 10.1002/rcm.7299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 07/30/2015] [Accepted: 08/03/2015] [Indexed: 05/31/2023]
Abstract
RATIONALE Rapid sub-species characterization of pathogens is required for timely responses in outbreak situations. Pyrolysis mass spectrometry (PyMS) has the potential to be used for this purpose. METHODS However, in order to make PyMS practical for traceback applications, certain improvements related to spectrum reproducibility and data acquisition speed were required. The main objectives of this study were to facilitate fast detection (<30 min to analyze 6 samples, including preparation) and sub-species-level bacterial characterization based on pattern recognition of mass spectral fingerprints acquired from whole cells volatilized and ionized at atmospheric pressure. An AccuTOF DART mass spectrometer was re-engineered to permit ionization of low-volatility bacteria by means of Plasma Jet Ionization (PJI), in which an electric discharge, and, by extension, a plasma beam, impinges on sample cells. RESULTS Instrumental improvements and spectral acquisition methodology are described. Performance of the re-engineered system was assessed using a small challenge set comprised of assorted bacterial isolates differing in identity by varying amounts. In general, the spectral patterns obtained allowed differentiation of all samples tested, including those of the same genus and species but different serotypes. CONCLUSIONS Fluctuations of ±15% in bacterial cell concentrations did not substantially compromise replicate spectra reproducibility.
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Affiliation(s)
- Pierre Alusta
- Innovative Safety Technologies Branch, Systems Biology Div., National Center for Toxicological Research, Food Drug AdministrationJefferson, AR, USA
| | - Dan Buzatu
- Innovative Safety Technologies Branch, Systems Biology Div., National Center for Toxicological Research, Food Drug AdministrationJefferson, AR, USA
| | - Anna Williams
- Innovative Safety Technologies Branch, Systems Biology Div., National Center for Toxicological Research, Food Drug AdministrationJefferson, AR, USA
| | - Willie-Mae Cooper
- Innovative Safety Technologies Branch, Systems Biology Div., National Center for Toxicological Research, Food Drug AdministrationJefferson, AR, USA
| | - Olga Tarasenko
- University of Arkansas at Little Rock, Department of BiologyLittle Rock, AR, USA
| | - R Cameron Dorey
- Innovative Safety Technologies Branch, Systems Biology Div., National Center for Toxicological Research, Food Drug AdministrationJefferson, AR, USA
| | - Reggie Hall
- Bionetics Corp., National Center for Toxicological Research, Food Drug AdministrationJefferson, AR, USA
| | - W Ryan Parker
- Department of Chemistry, University of TexasAustin, TX, USA
| | - Jon G Wilkes
- Innovative Safety Technologies Branch, Systems Biology Div., National Center for Toxicological Research, Food Drug AdministrationJefferson, AR, USA
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Global and Targeted Lipid Analysis of Gemmata obscuriglobus Reveals the Presence of Lipopolysaccharide, a Signature of the Classical Gram-Negative Outer Membrane. J Bacteriol 2015; 198:221-36. [PMID: 26483522 DOI: 10.1128/jb.00517-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 10/10/2015] [Indexed: 01/22/2023] Open
Abstract
UNLABELLED Planctomycete bacteria possess many unusual cellular properties, contributing to a cell plan long considered to be unique among the bacteria. However, data from recent studies are more consistent with a modified Gram-negative cell plan. A key feature of the Gram-negative plan is the presence of an outer membrane (OM), for which lipopolysaccharide (LPS) is a signature molecule. Despite genomic evidence for an OM in planctomycetes, no biochemical verification has been reported. We attempted to detect and characterize LPS in the planctomycete Gemmata obscuriglobus. We obtained direct evidence for LPS and lipid A using electrophoresis and differential staining. Gas chromatography-mass spectrometry (GC-MS) compositional analysis of LPS extracts identified eight different 3-hydroxy fatty acids (3-HOFAs), 2-keto 3-deoxy-d-manno-octulosonic acid (Kdo), glucosamine, and hexose and heptose sugars, a chemical profile unique to Gram-negative LPS. Combined with molecular/structural information collected from matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) MS analysis of putative intact lipid A, these data led us to propose a heterogeneous hexa-acylated lipid A structure (multiple-lipid A species). We also confirmed previous reports of G. obscuriglobus whole-cell fatty acid (FA) and sterol compositions and detected a novel polyunsaturated FA (PUFA). Our confirmation of LPS, and by implication an OM, in G. obscuriglobus raises the possibility that other planctomycetes possess an OM. The pursuit of this question, together with studies of the structural connections between planctomycete LPS and peptidoglycans, will shed more light on what appears to be a planctomycete variation on the Gram-negative cell plan. IMPORTANCE Bacterial species are classified as Gram positive or negative based on their cell envelope structure. For 25 years, the envelope of planctomycete bacteria has been considered a unique exception, as it lacks peptidoglycan and an outer membrane (OM). However, the very recent detection of peptidoglycan in planctomycete species has provided evidence for a more conventional cell wall and raised questions about other elements of the cell envelope. Here, we report direct evidence of lipopolysaccharide in the planctomycete G. obscuriglobus, suggesting the presence of an OM and supporting the proposal that the planctomycete cell envelope is an extension of the canonical Gram-negative plan. This interpretation features a convoluted cytoplasmic membrane and expanded periplasmic space, the functions of which provide an intriguing avenue for future investigation.
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Cox CR, Jensen KR, Saichek NR, Voorhees KJ. Strain-level bacterial identification by CeO2-catalyzed MALDI-TOF MS fatty acid analysis and comparison to commercial protein-based methods. Sci Rep 2015; 5:10470. [PMID: 26190224 PMCID: PMC4507139 DOI: 10.1038/srep10470] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Accepted: 04/16/2015] [Indexed: 12/27/2022] Open
Abstract
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has emerged as a rapid approach for clinical bacterial identification. However, current protein-based commercial bacterial ID methods fall short when differentiating closely related species/strains. To address this shortcoming, we employed CeO2-catalyzed fragmentation of lipids to produce fatty acids using the energy inherent to the MALDI laser as a novel alternative to protein profiling. Fatty acid profiles collected from Enterobacteriaceae, Acinetobacter, and Listeria using CeO2-catalyzed metal oxide laser ionization (MOLI MS), processed by principal component analysis, and validated by leave-one-out cross-validation (CV), showed 100% correct classification at the species level and 98% at the strain level. In comparison, protein profile data from the same bacteria yielded 32%, 54% and 67% mean species-level accuracy using two MALDI-TOF MS platforms, respectively. In addition, several pathogens were misidentified by protein profiling as non-pathogens and vice versa. These results suggest novel CeO2-catalyzed lipid fragmentation readily produced (i) taxonomically tractable fatty acid profiles by MOLI MS, (ii) highly accurate bacterial classification and (iii) consistent strain-level ID for bacteria that were routinely misidentified by protein-based methods.
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Affiliation(s)
- C R Cox
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401
| | - K R Jensen
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401
| | - N R Saichek
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401
| | - K J Voorhees
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401
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Zhang JI, Costa AB, Tao WA, Cooks RG. Direct detection of fatty acid ethyl esters using low temperature plasma (LTP) ambient ionization mass spectrometry for rapid bacterial differentiation. Analyst 2011; 136:3091-7. [DOI: 10.1039/c0an00940g] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Tracing the food sources of isolated strains of Listeria monocytogenes through fatty acid profiles analysis. Food Control 2010. [DOI: 10.1016/j.foodcont.2010.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Moldoveanu S. Chapter 19 Pyrolysis of Various Derivatives of Carboxylic Acids. PYROLYSIS OF ORGANIC MOLECULES WITH APPLICATIONS TO HEALTH AND ENVIRONMENTAL ISSUES 2010. [DOI: 10.1016/s0167-9244(09)02819-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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13
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Gidden J, Denson J, Liyanage R, Ivey DM, Lay JO. Lipid Compositions in Escherichia coli and Bacillus subtilis During Growth as Determined by MALDI-TOF and TOF/TOF Mass Spectrometry. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2009; 283:178-184. [PMID: 20161304 PMCID: PMC2699300 DOI: 10.1016/j.ijms.2009.03.005] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Lipids in Escherichia coli and Bacillus subtilis were analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and TOF/TOF tandem mass spectrometry. Lipids were extracted from bacterial cells using an equal volume mixture of dichloromethane, ethanol, and water, which formed a biphasic system with the lipids in the organic layer. The resulting mass spectra of the extracts from both bacteria showed a series of peaks corresponding to sodiated phospholipids - primarily phosphatidylethanolamines (PE) and phosphatidylglycerols (PG). The relative amounts of the phospholipids and the fatty acid compositions inferred from the spectra were in good agreement with previously reported values from GC/MS and thin-layer chromatography studies. E. coli and B. subtilis were easily differentiated by dissimilarities in the composition and relative amounts of the phospholipids present as well as by the presence of lysyl-phosphatidylglycerol and diglucosyl diglycerides solely in the B. subtilis mass spectra. Changes in lipid content in the bacteria during their growth phases were also monitored. In E. coli, the spectra indicated an increase in the amount of the unique C(cy-17) fatty acid (in which the fatty acid chain contains a cyclopropane ring) formed during exponential growth. During stationary growth, the spectra indicated an increase in the amount of saturated fatty acids. In B. subtilis, the phospholipid composition remained relatively unchanged during exponential growth, but the amount of PG slightly decreased while the amount of PE slightly increased during stationary growth. No significant changes were observed for the lysyl-phosphatidylglycerols or glycolipids during the exponential or stationary growth phases.
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Affiliation(s)
- Jennifer Gidden
- Arkansas Statewide Mass Spectrometry Facility, University of Arkansas, Fayetteville, AR 72701
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Al-Halbouni D, Dott W, Hollender J. Occurrence and composition of extracellular lipids and polysaccharides in a full-scale membrane bioreactor. WATER RESEARCH 2009; 43:97-106. [PMID: 18996555 DOI: 10.1016/j.watres.2008.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Revised: 09/27/2008] [Accepted: 10/07/2008] [Indexed: 05/27/2023]
Abstract
The aim of this study was to characterize the polysaccharides and lipid fractions of membrane foulants in a full-scale membrane bioreactor (MBR) treating municipal wastewater. Both of these polymeric compounds are major components of bacterial lipopolysaccharides and are impacting membrane fouling; however most of the data so far have been collected by determining sum parameters rather than the detailed composition of these polymers. Photometric analysis of sugars showed that uronic acids (glucuronic, mannuronic and galacturonic acid) as common units of bacterial polysaccharides accounted for 8% (w/w) of extracellular polymeric substances (EPS) in activated sludge flocs. Further the so-called polysaccharide peak of EPS, with a molecular weight >10 kDa according to size exclusion chromatography, was proven to contain bacterial sugar units as shown by high resolution LC-MS. Interestingly, only traces of uronic acids could be detected in EPS of the membrane fouling layer. A far more dramatic enrichment in the fouling layer was revealed for the lipid fraction of EPS, which was determined as fatty acid methyl esters by GC-MS. The weight percentage of fatty acids in EPS extracted from fouled ultrafiltration membranes was much higher (10%) than in the activated sludge itself (1-3%). The fatty acids accumulated on the membrane fouling layer were obviously not only of microbial origin (C16:0, C18:0) but also derived from the raw wastewater itself (C9:0). Hydrophobic interaction of lipids with the PVDF (polyvinylidene fluoride) membrane material therefore seems a plausible explanation for the observed fouling phenomenon. The results suggest that fatty acids from bacterial lipopolysaccharides as well as from synthetic sources are of much higher relevance to membrane fouling than previously assumed.
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Affiliation(s)
- Djamila Al-Halbouni
- Institute of Hygiene and Environmental Health, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen, Germany.
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Schlichting A, Leinweber P. New evidence for the molecular-chemical diversity of potato plant rhizodeposits obtained by pyrolysis-field Ionisation mass spectrometry. PHYTOCHEMICAL ANALYSIS : PCA 2009; 20:1-13. [PMID: 18618895 DOI: 10.1002/pca.1080] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
INTRODUCTION Detailed descriptions of the molecular-chemical diversity in plant rhizodeposits are scarce. The vast majority of our knowledge is derived from a priori methods of analysis, such as GC-MS and HPLC. OBJECTIVE To analyse the composition of rhizodeposits from the potato cultivar Solanum tuberosum L. cv. Albatros by pyrolysis -field ionisation mass spectrometry (Py-FIMS) and to explain differences in relation to plant growth stage and photoperiod. METHODOLOGY Potato (Solanum tuberosum L.) plants were grown in non-sterile, native soil under controlled environmental conditions (plant chamber). Rhizodeposit samples were collected by leaching during two different growth stages and after the physiological day- and night-cycle. All leachate samples were investigated by Py-FIMS. Mass spectrometric data were evaluated by multivariate statistics. RESULTS Screening of the rhizodeposits by Py-FIMS revealed a broad range of m/z signals. Low-molecular-weight substances of m/z 15-56 (8.1-18.6%), alkylaromatics (12.0-15.9%), phenols and lignin monomers (8.8-13.1%) and carbohydrates (6.0-11.2%) comprised the largest proportions of total ion intensity (TII). Mass signals with significantly different abundance at the various sampling dates were assigned to compound classes of carbohydrates, phenols and lignin monomers, lignin dimers, lipids, N-containing compounds, sterols, peptides and free fatty acids; these were supplemented by marker signals for N-acetylmuramic acid from bacterial cell walls and signal molecules for the regulation of secondary pathways such as 4-hydroxycinnamic acid and linolenic acid. CONCLUSION Py-FIMS was well suited to detect the molecular-chemical diversity of potato plant rhizodeposits and, compared with traditional a priori analytical methods, provided detailed evidence for significant differences in the composition of rhizodeposits depending on growth stage and diurnal period.
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Affiliation(s)
- André Schlichting
- Steinbeis Transferzentrum Soil Biotechnology, D-18190 Gross Lüsewitz, Germany
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16
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Parisi D, Magliulo M, Nanni P, Casale M, Forina M, Roda A. Analysis and classification of bacteria by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and a chemometric approach. Anal Bioanal Chem 2008; 391:2127-34. [DOI: 10.1007/s00216-008-2161-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2008] [Revised: 04/22/2008] [Accepted: 04/23/2008] [Indexed: 10/22/2022]
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17
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Meetani MA, Shin YS, Zhang S, Mayer R, Basile F. Desorption electrospray ionization mass spectrometry of intact bacteria. JOURNAL OF MASS SPECTROMETRY : JMS 2007; 42:1186-93. [PMID: 17628040 DOI: 10.1002/jms.1250] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Desorption electrospray ionization (DESI) mass spectrometry (MS) was used to differentiate seven bacteria species on the basis of their measured DESI-mass spectral profile. Both gram-positive and gram-negative bacteria were tested and included Escherichia coli, Staphyloccocus aureus, Enterococcus sp., Bordetella bronchiseptica, Bacillus thuringiensis, Bacillus subtilis and Salmonella typhimurium. Distinct DESI-mass spectra, in the mass range of 50-500 u, were obtained from whole bacteria in either positive or negative ion modes in less than 2 mins analysis time. Positive ion DESI-mass spectral fingerprints were compared using principal components analysis (PCA) to investigate reproducibility for the intraday and the day-to-day measurements and the method selectivity to differentiate the bacteria studied. Detailed study of variances in the assay revealed that a large contribution to the DESI-mass spectral fingerprint variation was the growth media preparation procedure. Specifically, experiments conducted with the growth media prepared using the same batch yielded highly reproducible DESI-mass spectra, both in intraday and in day-to-day analyses (i.e. one batch of growth media used over a 3-day period versus a new batch every day over the same 3-day period). Conclusions are drawn from our findings in terms of strategies for rapid biodetection with DESI-MS.
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Affiliation(s)
- Mohammed A Meetani
- Department of Chemistry, Faculty of Science, United Arab Emirates University, Al Ain, United Arab Emirates
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18
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Zhang S, Basile F. Site-specific pyrolysis-induced cleavage at aspartic acid residue in peptides and proteins. J Proteome Res 2007; 6:1700-4. [PMID: 17388620 PMCID: PMC3176669 DOI: 10.1021/pr060648w] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A simple and site-specific nonenzymatic method based on pyrolysis has been developed to cleave peptides and proteins. Pyrolytic cleavage was found to be specific and rapid as it induced a cleavage at the C-terminal side of aspartic acid in the temperature range of 220-250 degrees C in 10 s. Electrospray ionization (ESI) mass spectrometry (MS) and tandem-MS (MS/MS) were used to characterize and identify pyrolysis cleavage products, confirming that sequence information is conserved after the pyrolysis process in both peptides and protein tested. This suggests that pyrolysis-induced cleavage at aspartyl residues can be used as a rapid protein digestion procedure for the generation of sequence-specific protein biomarkers.
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Affiliation(s)
| | - Franco Basile
- To whom correspondence should be addressed. Department of Chemistry, University of Wyoming, 1000 E. University Ave. (3838), Laramie, Wyoming 82071. Tel: (307) 766-4376. Fax: (307) 766-2807.
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19
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Prasad S, Schmidt H, Lampen P, Wang M, Güth R, Rao JV, Smith GB, Eiceman GA. Analysis of bacterial strains with pyrolysis-gas chromatography/differential mobility spectrometry. Analyst 2006; 131:1216-25. [PMID: 17066190 DOI: 10.1039/b608127d] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Eight vegetative bacterial strains and two spores were characterized by pyrolysis-gas chromatography with differential mobility spectrometry (py-GC/DMS) yielding topographic plots of ion intensity, retention time, and compensation voltage simultaneously for ions in positive and negative polarity. Biomarkers were found in the pyrolysate at characteristic retention times and compensation voltages and were confirmed by standard addition with GC/MS analyses providing discrimination between Gram negative and Gram positive bacterial types, but no recognition of individual strains within the Gram negative bacteria. Principal component analysis was applied using two dimensional data sets of ion intensity versus retention time at five compensation voltages including the reactant ion peaks all in positive and negative ion polarity. Clustering was observed with compensation voltage (CV) chromatograms associated with ion separation in the DMS detector and little or no clustering was observed with the reactant ion peaks or CV chromatograms where ion separation is poor. Consistent clustering of Gram positive B. odysseyi and Gram negative E. coli in both positive and negative polarities with the reactant ion peak chromatograms and key CV chromatograms suggests common but unknown common chemical compositions in the pyrolysate.
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Affiliation(s)
- Satendra Prasad
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003, USA
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20
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Jones JJ, Borgmann S, Wilkins CL, O'Brien RM. Characterizing the Phospholipid Profiles in Mammalian Tissues by MALDI FTMS. Anal Chem 2006; 78:3062-71. [PMID: 16642994 DOI: 10.1021/ac0600858] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Discussed here is an analytical method for profiling lipids and phospholipids directly from mammalian tissues excised from Mus musculus (house mouse). Biochemical analysis was accomplished through the use of matrix-assisted laser desorption/ionization (MALDI) Fourier transform mass spectrometry, where whole tissue sections of mouse brain, heart, and liver were investigated. Lipid and phospholipid ions create complex MALDI mass spectra containing multiple ions with different m/z values corresponding to the same fundamental chemical species. When a computational sorting approach is used to group these ions, the standard deviation for observed relative chemical abundance can be reduced to 6.02%. Relative standard deviations of 10% are commonly accepted for standard chromatographic phospholipid analyses. Average mass measurement accuracy for 232 spectra representing three tissue types from 12 specimens was calculated to be 0.0053 Da. Further it is observed, that the data and the analysis between all the animals have near-identical phospholipid contents in their brain, heart, and liver tissues, respectively. In addition to the need to accurately measure relative abundances of phospholipid species, it is essential to have adequate mass resolution for complete and accurate overall analysis. It is reasonable to make mass composition assignments with spectral resolving power greater than 8000. However, results from the present study reveal 14 instances (C12 carbon isotope) of multiple m/z ions having the same nominal value that require greater resolution in order that overlap will not occur. Spectra measured here have an average resolving power of 12 000. It is established that high mass resolution and mass accuracy coupled with MALDI ionization provide for rapid and accurate phospholipid analysis of mammalian tissue sections.
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Affiliation(s)
- Jeffrey J Jones
- Department of Chemistry and Biochemistry, University of Arkansas, University of Arkansas, Fayetteville, Arkansas 72701, USA
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21
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Cai SS, Syage JA. Comparison of Atmospheric Pressure Photoionization, Atmospheric Pressure Chemical Ionization, and Electrospray Ionization Mass Spectrometry for Analysis of Lipids. Anal Chem 2006; 78:1191-9. [PMID: 16478111 DOI: 10.1021/ac0515834] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this work, we compare the quantitative accuracy and sensitivity of analyzing lipids by atmospheric pressure photoionization (APPI), atmospheric pressure chemical ionization (APCI), and electrospray ionization (ESI) LC/MS. The target analytes include free fatty acids and their esters, monoglyceride, diglyceride, and triglyceride. The results demonstrate the benefits of using LC/APPI-MS for lipid analysis. Analyses were performed on a Waters ZQ LC/MS. Normal-phase solvent systems were used due to low solubility of these compounds in aqueous reversed-phase solvent systems. By comparison, APPI offers lower detection limits, generally highest signal intensities, and the highest S/N ratio. APPI is 2-4 times more sensitive than APCI and much more sensitive than ESI without mobile-phase modifiers. APPI and APCI offer comparable linear range (i.e., 4-5 decades). ESI sensitivity is dramatically enhanced by use of mobile phase modifiers (i.e., ammonium formate or sodium acetate); however, these ESI adduct signals are less stable and either are nonlinear or have dramatically reduced linear ranges. Analysis of fish oils by APPI shows significantly enhanced target analyte intensities in comparison with APCI and ESI.
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Affiliation(s)
- Sheng-Suan Cai
- Syagen Technology Inc., 1411 Warner Avenue, Tustin, CA 92780, USA
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22
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Jones JJ, Stump MJ, Fleming RC, Lay JO, Wilkins CL. Strategies and data analysis techniques for lipid and phospholipid chemistry elucidation by intact cell MALDI-FTMS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2004; 15:1665-74. [PMID: 15519235 DOI: 10.1016/j.jasms.2004.08.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2004] [Revised: 07/29/2004] [Accepted: 08/04/2004] [Indexed: 05/13/2023]
Abstract
Ions attributed to lipids and phospholipids are directly observed by desorption from whole bacteria using intact cell (IC) matrix-assisted laser desorption-ionization (MALDI) Fourier transform mass spectrometry (FTMS). Saccharomyces cerevisiae are grown in rich media broth, concentrated, and applied directly to the MALDI surface without lysis or chemical treatment. FTMS of MALDI ions gives excellent signal to noise ratios with typical resolving powers of 90,000 and mass precision better than 0.002 Da. Use of accurate mass measurements and a simple set of rules allow assignment of major peaks into one of twelve expected lipid classes. Subsequently, fractional mass versus whole number mass plots are employed to enhance visual interpretation of the high-resolution data and to facilitate detection of related ions such as those representing homologous series or different degrees of unsaturation. This approach, coupled with rules based on bacterial biochemistry, is used to classify ions with m/z up to about 1000. Major spectral peaks in the range m/z 200-1000 are assigned as lipids and phospholipids. In this study, it is assumed that biologically-derived ions with m/z values lower than 1000 are lipids. This is not unreasonable in view of the facts that molecular weights of lipids are almost always less than 1000 Da, that the copy numbers for lipids in a cell are higher than those for any single protein or other component, and that lipids are generally collections of distinct homologous partners, unlike proteins or other cell components. This paper presents a new rapid lipid-profiling method based on IC MALDI-FTMS.
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Affiliation(s)
- Jeffrey J Jones
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, USA
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23
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Conrad A, Suutari MK, Keinänen MM, Cadoret A, Faure P, Mansuy-Huault L, Block JC. Fatty acids of lipid fractions in extracellular polymeric substances of activated sludge flocs. Lipids 2003; 38:1093-105. [PMID: 14669975 DOI: 10.1007/s11745-006-1165-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Phospholipid (PL), glycolipid (GL), and neutral lipid (NL) FA, and the lipopolysaccharide 2- and 3-hydroxy (LPS 2-OH and 3-OH) FA of activated sludges and extracted extracellular polymeric substances (EPS) were determined on samples collected from two wastewater treatment plants. EPS extracted from sludges by means of sonication and cation exchange contained proteins (43.4%), humic-like substances (11.5%), nucleic acids (10.9%), carbohydrates (9.9%), and lipid-bound FA (1.8%). The lipids associated with EPS were composed of GL, PL, NL, and LPS acids in proportions of 61, 21, 16, and 2%, respectively. The profiles of lipid-bound FA in activated sludges and EPS were similar (around 85 separate FA were identified). The FA signatures observed can be attributed to the likely presence of yeasts, fungi, sulfate-reducing bacteria, gram-positive and gram-negative bacteria, and, in lesser quantities, mycobacteria. Comparison of data from the dates of sampling (January and September) showed that there were more unsaturated PLFA in the EPS extracted from the activated sludges sampled in January. This observation could be partly related to microorganism adaptation to temperature variations. The comparison between two wastewater treatment plants showed that the FA profiles were similar, although differences in microbial community structure were also seen. Most of the FA in sludges had an even number of carbons.
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Affiliation(s)
- Arnaud Conrad
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564 CNRS--Université Henri Poincaré, Faculté de Pharmacie, Pôle de l'Eau, 54500 Vandoeuvre-lès-Nancy, France
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24
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Differentiation and classification of user-specified bacterial groups by in situ thermal hydrolysis and methylation of whole bacterial cells with tert -butyl bromide chemical ionization ion trap mass spectrometry. Anal Chim Acta 2000. [DOI: 10.1016/s0003-2670(00)00952-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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25
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26
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Beverly MB, Basile F, Voorhees KJ, Hadfield TL. The effects of electron and chemical ionization modes on the MS profiling of whole bacteria. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 1999; 10:747-758. [PMID: 10439512 DOI: 10.1016/s1044-0305(99)00050-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Free fatty acid profiling of whole bacteria [Francisella tularensis, Brucella melitensis, Yersinia pestis, Bacillus anthracis (vegetative and sporulated), and Bacillus cereus] was carried out with direct probe mass spectrometry under 70-eV electron ionization (EI) and isobutane chemical ionization in both the positive (CI+) and negative modes (CI-). Electron ionization produced spectra that contained molecular ions and fragment ions from various free fatty acids. Spectra acquired with isobutane chemical ionization in the positive mode yielded molecular ions of free fatty acids as well as ions from other bacterial compounds not observed under EI conditions. Spectra obtained with negative chemical ionization did not contain as much taxonomic information as EI or CI+; however, some taxonomically significant compounds such as dipicolinic acid and poly(3-hydroxybutyrate) did produce negative ions. All ionization modes yielded spectra that could separate the bacteria by Gram-type when observed with principle components analysis (PCA). Chemical ionization in the positive ion mode produced the greatest amount of differentiation between the four genera of bacteria when the spectra where examined by PCA.
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Affiliation(s)
- M B Beverly
- Chemistry and Geochemistry Department, Colorado School of Mines, Golden 80401, USA
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27
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Arnold RJ, Karty JA, Ellington AD, Reilly JP. Monitoring the growth of a bacteria culture by MALDI-MS of whole cells. Anal Chem 1999; 71:1990-6. [PMID: 10361498 DOI: 10.1021/ac981196c] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have probed the time evolution of a growing bacteria culture by extracting samples periodically and performing matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) on whole cells. The mass spectra generated by this method contain tens of peaks in the 3-11-kDa mass range. Cultures of E. coli strain K-12 were grown in two types of containers and at two nutrient concentrations and sampled periodically from 6 to 84 h after inoculation. The relative intensities of several of the stronger peaks vary quite dramatically as a function of time. These temporal characteristics must be taken into account when MALDI-MS is applied to identify bacteria. The results also suggest that MALDI-MS can be used to follow the aging of a bacteria culture.
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Affiliation(s)
- R J Arnold
- Department of Chemistry, Indiana University, Bloomington 47405, USA
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28
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Barshick SA, Wolf DA, Vass AA. Differentiation of microorganisms based on pyrolysis-ion trap mass spectrometry using chemical ionization. Anal Chem 1999; 71:633-41. [PMID: 9989380 DOI: 10.1021/ac980356h] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ability to differentiate microorganisms using pyrolysision trap mass spectrometry was demonstrated for five Gram-negative disease-causing organisms: Brucella melitensis, Brucella suis, Vibrio cholera, Yersinia pestis, and Francisella tularensis. Bacterial profiles were generated for gamma-irradiated bacterial samples using pyrolytic methylation and compared for electron ionization and chemical ionization using several liquid reagents with increasing proton affinities. Electron ionization combined with pyrolysis caused extensive fragmentation, resulting in a high abundance of lower mass ions and diminishing the diagnostic value of the technique for compound identification and bacterial profiling. Chemical ionization reduced the amount of fragmentation due to ionization while enhancing the molecular ion region of the fatty acids. As the proton affinity of the reagent increased, the protonated molecular ions of the fatty acids became the predominant ions observed in the mass spectrum. As a result, chemical ionization was shown to be more effective than electron ionization in bacterial profiling. Whereas the bacteria could be distinguished at the Genera level using electron ionization, further differentiation to the subspecies level was possible using chemical ionization. The greatest separation among the five test organisms, in terms of Euclidean distances, was obtained using ethanol as the chemical ionization reagent and using pooled masses representing specific fatty acid biomarkers rather than total ion profiles.
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Affiliation(s)
- S A Barshick
- Oak Ridge National Laboratory, Tennessee 37831, USA.
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29
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Basile F, Beverly MB, Abbas-Hawks C, Mowry CD, Voorhees KJ, Hadfield TL. Direct mass spectrometric analysis of in situ thermally hydrolyzed and methylated lipids from whole bacterial cells. Anal Chem 1998; 70:1555-62. [PMID: 9569765 DOI: 10.1021/ac970970d] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Fatty acid methyl esters (FAMEs) were generated in situ, during pyrolysis, from whole-cell bacterial samples and analyzed by mass spectrometry (MS). The FAME profiles obtained by an in situ thermal hydrolysis methylation (THM) step were compared with gas chromatography (GC) and MS analyses of the chemically extracted and methylated fatty acids. This correlation was based on the ability of each technique to differentiate a representative group of 15 bacteria at the species level as predicted by principal component analysis. All three analyses, GC/FAME, pyrolysis-MS/FAME, and in situ THM-MS/FAME differentiated the studied bacterial sample set into three discrete clusters. The bacteria comprising each cluster were the same for all three analyses, showing that taxonomic information of the lipid profiles was preserved in the Py-MS/FAME and in situ THM-MS/FAME analyses of whole cells. Contributions from saturated, unsaturated, cyclopropyl, and branched bacterial fatty acids to the differentiation of microorganisms were identified for all three analyses. The in situ THM-MS/FAME approach is simple, requires small samples (approximately 2 x 10(6) cells/profile), and is rapid, with a total analysis time under 5 min/sample.
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Affiliation(s)
- F Basile
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden 80401-1887, USA
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30
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Basile F, Beverly MB, Voorhees KJ, Hadfield TL. Pathogenic bacteria: their detection and differentiation by rapid lipid profiling with pyrolysis mass spectrometry. Trends Analyt Chem 1998. [DOI: 10.1016/s0165-9936(97)00103-9] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Gharaibeh AA, Voorhees KJ. Characterization of lipid fatty acids in whole-cell microorganisms using in situ supercritical fluid derivatization/extraction and gas chromatography/mass spectrometry. Anal Chem 1996; 68:2805-10. [PMID: 8794917 DOI: 10.1021/ac9600767] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In situ supercritical fluid derivatization and extraction was used as a sample preparation technique for the classification of bacteria using fatty acid profiling. Addition of a quaternary ammonium salt such as phenyltrimethylammonium hydroxide under static supercritical conditions directly to lyophilized, whole-cell bacteria in an extraction vessel resulted in the saponification of the bacterial lipids and derivatization of their fatty acids. The derivatized fatty acid methyl esters (FAMEs) were then extracted with supercritical CO2 and analyzed without additional treatment using GC/MS. Iso and anteiso C15:0 and C17:0 along with C18:0 were predominant in Gram-positive bacteria, while C16:1, C16:0, C18:1, and cyclopropyl cyC17:0 and cyC19:0 were significant in Gram-negative bacteria. Application of principal components analysis to the FAME GC/MS data resulted in the differentiation between Gram-positive and Gram-negative type bacteria. Differentiation between species among the same genera was also observed.
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Affiliation(s)
- A A Gharaibeh
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden 80401, USA
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32
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Affiliation(s)
- Steven D. Brown
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716-2522
| | - Stephen T. Sum
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716-2522
| | - Frederic Despagne
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716-2522
| | - Barry K. Lavine
- Department of Chemistry, Clarkson University, Potsdam, New York 13676
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Abstract
Pyrolysis mass spectrometry is a rapid and high-resolution method for the analysis of otherwise non-volatile material and has been widely applied for discriminating between closely related microbial strains. Recent advances in statistical and neural network methods based on supervised learning have now permitted exploitation of pyrolysis mass spectrometry in the quantitative analysis of many diverse samples of biotechnological interest; the technique may thus be regarded as an 'anything-sensor'.
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Affiliation(s)
- R Goodacre
- Institute of Biological Sciences, University of Wales, Aberystwyth, Dyfed, SY23 3DA, UK
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