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Lot verification practices in Ontario clinical chemistry laboratories - Results of a patterns-of-practice survey. Pract Lab Med 2022; 32:e00300. [PMID: 36035320 PMCID: PMC9399155 DOI: 10.1016/j.plabm.2022.e00300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 07/11/2022] [Accepted: 08/05/2022] [Indexed: 11/30/2022] Open
Abstract
Objectives Verifying new reagent or calibrator lots is crucial for maintaining consistent test performance. The Institute for Quality Management in Healthcare (IQMH) conducted a patterns-of-practice survey and follow-up case study to collect information on lot verification practices in Ontario. Methods The survey had 17 multiple-choice questions and was distributed to 183 licensed laboratories. Participants provided information on materials used and approval/rejection criteria for their lot verification procedures for eight classes of testing systems. The case study provided a set of lot comparison data and was distributed to 132 laboratories. Responses were reviewed by IQMH scientific committees. Results Of the 175 laboratories that responded regarding reagent lot verifications, 74% verified all tests, 11% some, and 15% none. Of the 171 laboratories that responded regarding calibrator lot verifications, 39% verified all calibrators, 4% some, and 57% none. Reasons for not performing verifications ranged from difficulty performing parallel testing to high reagent cost. For automated chemistry assays and immunoassays, 23% of laboratories did not include patient-derived materials in reagent lot verifications and 42% included five to six patient materials; 58% of laboratories did not include patient-derived materials in calibrator lot verifications and 23% included five to six patient materials. Different combinations of test-specific rules were used for acceptance criteria. For a failed lot, 98% of laboratories would investigate further and take corrective actions. Forty-three percent of laboratories would accept the new reagent lot in the case study. Conclusion Responses to the survey and case study demonstrated variability in lot verification practices among laboratories. Surveyed laboratories verified new reagent lots more commonly than calibrator lots. Quality control material was used more than patient material for lot verifications. Quality control results with a new lot were compared most to 2 standard deviations. Percent difference was used most to assess patient material results between lots. Laboratories need feasible guidelines on reagent and calibrator lot verifications.
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Key Words
- CLSI, Clinical and Laboratory Standards Institute
- Calibrator
- ELISA, enzyme-linked immunosorbent assay
- GC, gas chromatography
- HPLC, high-performance liquid chromatography
- IQMH, Institute for Quality Management in Healthcare
- ISO, International Organization for Standardization
- LC-MS/MS, liquid chromatography tandem mass spectrometry
- Lot number
- PT, proficiency testing
- QC, quality control
- RIA, radioimmunoassay
- Reagent
- TSH, thyroid-stimulating hormone
- Verification
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Analysis of 2-methylcitric acid, methylmalonic acid, and total homocysteine in dried blood spots by LC-MS/MS for application in the newborn screening laboratory: A dual derivatization approach. J Mass Spectrom Adv Clin Lab 2021; 20:1-10. [PMID: 34820666 PMCID: PMC8601015 DOI: 10.1016/j.jmsacl.2021.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 03/01/2021] [Accepted: 03/03/2021] [Indexed: 11/19/2022] Open
Abstract
Inborn errors of propionate, cobalamin and methionine metabolism are targets for Newborn Screening (NBS) in most programs world-wide, and are primarily screened by analyzing for propionyl carnitine (C3) and methionine in dried blood spot (DBS) cards using tandem mass spectrometry (MS/MS). Single-tier NBS approaches using C3 and methionine alone lack specificity, which can lead to an increased false-positive rate if conservative cut-offs are applied to minimize the risk of missing cases. Implementation of liquid chromatography tandem mass spectrometry (LC-MS/MS) second-tier testing for 2-methylcitric acid (MCA), methylmalonic acid (MMA), and homocysteine (HCY) from the same DBS card can improve disease screening performance by reducing the false-positive rate and eliminating the need for repeat specimen collection. However, DBS analysis of MCA, MMA, and HCY by LC-MS/MS is challenging due to limited specimen size and analyte characteristics leading to a combination of low MS/MS sensitivity and poor reverse-phase chromatographic retention. Sufficient MS response and analytical performance can be achieved for MCA by amidation using DAABD-AE and by butylation for MMA and HCY. Herein we describe the validation of a second-tier dual derivatization LC-MS/MS approach to detect elevated MCA, MMA, and HCY in DBS cards for NBS. Clinical utility was demonstrated by retrospective analysis of specimens, an interlaboratory method comparison, and assessment of external proficiency samples. Imprecision was <10.8% CV, with analyte recoveries between 90.2 and 109.4%. Workflows and analytical performance characteristics of this second-tier LC-MS/MS approach are amenable to implementation in the NBS laboratory.
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Key Words
- 2-Methylcitric acid
- C2, acetylcarnitine
- C3, propionylcarnitine
- CBS, cystathionine β-synthase
- Cbl, cobalamin
- DAABD-AE, 4-[2-(N,N-dimethylamino)ethylaminosulfonyl]-7-(2-aminoethylamino)-2,1,3-benzoxadiazole
- DBS, dried blood spot
- DMAP, 4-(dimethylamino)pyridine
- DTT, dithiothreitol
- EDC, N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride
- ESI, electrospray ionization
- FA, formic acid
- GC, gas chromatography
- GPCho’s, glycerophosphocholines
- HCY, homocysteine
- HCl, hydrochloric acid
- Homocysteine
- LC, liquid chromatography
- LLOD, lower limit of detection
- LLOQ, lower limit of quantitation
- MCA, 2-methylcitric acid
- MMA, methylmalonic acid
- MPs, mobile phases
- MRM, multiple reaction monitoring
- MS, mass spectrometry
- MS/MS, tandem mass spectrometry
- Mass spectrometry
- Met, methionine
- Methylmalonic acid
- NBS, newborn screening
- Newborn screening
- PPV, positive predictive value
- Phe, phenylalanine
- QC, quality control
- S/N, signal-to-noise
- Second-tier
- rpm, revolutions per minute
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Assay of ethanol and congener alcohols in serum and beverages by headspace gas chromatography/mass spectrometry. MethodsX 2021; 8:101563. [PMID: 34754825 PMCID: PMC8563810 DOI: 10.1016/j.mex.2021.101563] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 10/27/2021] [Indexed: 12/24/2022] Open
Abstract
The analysis of ethanol and of its congeners in blood plays an important role in forensic cases, especially when allegations are made that alcohol has been consumed after an accident. In alcoholic beverages, congener alcohols are by-products and are generated during fermentation. The assay of these compounds in serum samples and beverages has been previously performed using headspace-gas chromatography-flame ionization detection methods (HS-GC-FID). As an alternative, a robust headspace-gas chromatography-mass spectrometry (HS-GC-MS) procedure was developed and validated, which has the following advantages:•Simultaneous determination of ethanol, congener alcohols and other endogenous substances.•Reduction of matrix interference by increasing selectivity and specificity.•Clear separation of the positional isomers 3-methyl-1-butanol and 2-methyl-1-butanol.
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Key Words
- 1-propanol
- Alcohol
- CV, coefficients of variation
- Cal, calibrator
- EI, electron impact ionization
- FID, flame ionization detection
- GC, gas chromatography
- GTFCh, Gesellschaft für Toxikologische und Forensische Chemie
- HS, headspace
- ISTD, internal standard
- LLOQ, lower limit of quantitation
- LOD, limit of detection
- MS, mass spectrometry
- Methanol
- Method validation
- Post-offence drinking
- QC, quality control
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In vitro fecal fermentation characteristics of bamboo shoot ( Phyllostachys edulis) polysaccharide. FOOD CHEMISTRY-X 2021; 11:100129. [PMID: 34585136 PMCID: PMC8453218 DOI: 10.1016/j.fochx.2021.100129] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/03/2021] [Accepted: 09/06/2021] [Indexed: 01/11/2023]
Abstract
The effects of Moso bamboo (Phyllostachys edulis) shoot polysaccharide (BSP) on the human gut microbiota composition and volatile metabolite components were investigated by in vitro fermentation. After fermentation for 48 h, BSP utilization reached 40.29% and the pH of the fermentation solution decreased from 6.89 to 4.57. Moreover, the total short-chain fatty acid concentration significantly (P < 0.05) increased from 13.46 mM (0 h) to 43.20 mM (48 h). 16S rRNA analysis revealed several differences in the gut microbiota community structure of the BSP-treated and water-treated (control) cultures. In the BSP group, the abundance of Firmicutes, Actinobacteria, and Proteobacteria was significantly increased, while that of Bacteroidetes and Fusobacteria significantly decreased. Moreover, the concentrations of benzene, its substituted derivatives, and carbonyl compounds in the volatile metabolites of the BSP-treated group decreased, while that of organic acids significantly increased after 48 h of fermentation. These results demonstrate that BSP improves gastrointestinal health.
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Key Words
- 16S rRNA
- ANOVA, one-way analysis of variance
- BSDF, bamboo shoot dietary fibre
- BSP, bamboo shoot polysaccharide
- GC, gas chromatography
- HPGPC, high-performance gel permeation chromatography
- HPLC, high-performance liquid chromatography
- Intestinal microbiota
- MS, mass spectrometry
- Microflora
- PCA, principal component analysis
- RT-PCR, reverse transcription-polymerase chain reaction
- SCFA, short-chain fatty acid
- Short-chain fatty acid
- TLC, thin-layer chromatography
- Volatile metabolite
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One-step separation system of bio-functional lipid compounds from natural sources. MethodsX 2021; 8:101380. [PMID: 34430276 PMCID: PMC8374514 DOI: 10.1016/j.mex.2021.101380] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 04/30/2021] [Indexed: 10/25/2022] Open
Abstract
Lipids are a very heterogeneous class of biomolecules with distinct structures and functions. Total lipids (TLs) obtained from natural sources are regularly further separated into lipid subclasses, with the two major ones being the polar lipids (PLs) and neutral lipids (NLs). Traditional analytical methods for fractionating TLs into NLs, PLs, and their subclasses, usually comprise difficult, costly and time-consuming steps. Instead, several benefits and applications are derived by implementing a novel one-step semi-preparative and reversed-phase HPLC-analysis for separating TLs into all kinds of lipid subclasses. This method allows a one-step separation/fractionation of several subclasses of bio-functional PLs (i.e. phospholipids, glycolipids, phenolic compounds, N-acyl-homoserine-lactones, etc.) and NLs (i.e. triacylglycerols, fatty acids, esters, etc.) from TL-extracts of a natural source, prior to further testing them for their bio-functionality (i.e. in bioassays/cell models) and structure-activity relationships (i.e. LC-MS/GC-MS).•This method can be applied in several natural sources, such as animal and marine sources, plants, microorganisms of biotechnological and agricultural interest, foods, beverages and related products, and by-products.•This method can also be applied for separating specific bio-functional lipids from complex medical and pharmaceutical samples (i.e. cells, tissues, blood, plasma, liposomes, etc.), either for evaluating their role in diseases (i.e. PAF/PAF-like molecules) or by elucidating their protective roles (i.e. PLs rich in ω3 PUFA) for supplements and nutraceuticals' applications.
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Antiviral activity of Lavandula angustifolia L. and Salvia officinalis L. essential oils against avian influenza H5N1 virus. JOURNAL OF AGRICULTURE AND FOOD RESEARCH 2021; 4:100135. [PMID: 36570026 PMCID: PMC9767472 DOI: 10.1016/j.jafr.2021.100135] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 02/12/2021] [Accepted: 02/24/2021] [Indexed: 05/21/2023]
Abstract
Nowadays, viral infection is considered a major cause of mortality all over the world such as covid-19 pandemic. In this context, searching for antiviral agents are major researchers interests. In this study, essential oils (EO) of Lavandula angustifolia (lavender) and Salvia officinalis (salvia) were subjected to combat avian influenza H5N1 virus. Laboratory trials were performed to identify Lavender and salvia EOs and evaluate their antioxidant, anti-inflammatory and antiviral activity against an avian influenza H5N1 virus. EOs were prepared by the hydrodistillation of air-dried plants and analyzed by GC-MS methods. The results revealed that salvia has the highest EOs yield 1.3% than lavender 1%. The dominant constituents of lavender EO were linalyl acetate and linalool while camphor and α-thujone were the dominant compounds of salvia. Both oils exhibited antioxidant activity in DPPH and ABTS and total antioxidant capacity assays. The results suggest the use of salvia and lavender EOs as effective natural anti-inflammatory, antioxidant and antiviral agents.
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Key Words
- ABTS•+, 2,2-azino-bis (3-ethylbenzothiazloine-6-sulphonic acid) radical cation
- Anti-inflammatory
- Antioxidant
- Antiviral
- Avian influenza
- BSA, bovine serum albumin
- DPPH•, 1,1-diphenyl-2-picrylhydrazyl radical
- Essential oils
- FID, flame ionization detector
- GC, gas chromatography
- GC-MS, gas chromatography-mass spectrometry
- Lavandula angustifolia
- MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide
- Salvia officinalis
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Use of a deactivated PTV injector liner and GCMS/MS for the quantitative determination of multiple pesticide residues in fruit and vegetables. MethodsX 2020; 8:101180. [PMID: 33364182 DOI: 10.1016/j.mex.2020.101180] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 11/20/2020] [Accepted: 12/07/2020] [Indexed: 11/18/2022] Open
Abstract
The quantitative determination of multiple pesticide residues in food is an iterative process given the frequent changes in monitoring specifications set by regulatory authorities, introduction of new pesticide active ingredients, variety of commodities encountered and advances in the capability of analytical instrumentation and software platforms. The method described here:•replaces our previous methodology [1] that was based on an ethyl acetate extraction [2], two different sample extract clean-up regimes depending on the commodity; either Gel Permeation Chromatography (GPC) or Solid Phase Extraction (SPE) and GC/MSMS analysis using cool on-column injection and permits higher throughput using the same QuEChERS extraction method used for LCMS/MS analysis [3]•uses PTV injection incorporating a deactivated (baffled) injection liner required to improve performance for 'difficult to analyse' pesticides e.g. captan, dichlofluanid, folpet, tolylfluanid.•has been validated for the quantitative determination of 113 different pesticides and their metabolites in a range of fruit and vegetables of high water content and high acid and high water content i.e. cabbage, lemon, pepper, plum and spinach and complies with requirements of European Commission guidance document on Analytical Quality Control and Method Validation Procedures for Pesticides Residues Analysis in food and feed - SANTE/12682/2019 [4].
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Key Words
- AP, analyte protectants
- Captan
- DSPE, dispersive solid phase extraction
- EU, European union
- Folpet
- Fruit and vegetables
- GC, gas chromatography
- GCB, graphitised carbon black
- GCMS/MS
- GCMS/MS, gas chromatography tandem mass spectrometry
- GPC, gel permeation chromatography
- ISTD, internal standard
- Injector liner
- PTV
- PTV, programmable temperature vapourising
- Pesticide residues
- QuEChERS
- RL, Reporting Level
- SPE, Solid Phase Extraction
- SRM, Simultaneous Reaction Monitoring
- UK, United Kingdom
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Analysis of urinary VOCs using mass spectrometric methods to diagnose cancer: A review. CLINICAL MASS SPECTROMETRY (DEL MAR, CALIF.) 2020; 18:27-37. [PMID: 34820523 PMCID: PMC8600992 DOI: 10.1016/j.clinms.2020.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/26/2020] [Accepted: 10/26/2020] [Indexed: 12/11/2022]
Abstract
The development of non-invasive screening techniques for early cancer detection is one of the greatest scientific challenges of the 21st century. One promising emerging method is the analysis of volatile organic compounds (VOCs). VOCs are low molecular weight substances generated as final products of cellular metabolism and emitted through a variety of biological matrices, such as breath, blood, saliva and urine. Urine stands out for its non-invasive nature, availability in large volumes, and the high concentration of VOCs in the kidneys. This review provides an overview of the available data on urinary VOCs that have been investigated in cancer-focused clinical studies using mass spectrometric (MS) techniques. A literature search was conducted in ScienceDirect, Pubmed and Web of Science, using the keywords "Urinary VOCs", "VOCs biomarkers" and "Volatile cancer biomarkers" in combination with the term "Mass spectrometry". Only studies in English published between January 2011 and May 2020 were selected. The three most evaluated types of cancers in the reviewed studies were lung, breast and prostate, and the most frequently identified urinary VOC biomarkers were hexanal, dimethyl disulfide and phenol; with the latter seeming to be closely related to breast cancer. Additionally, the challenges of analyzing urinary VOCs using MS-based techniques and translation to clinical utility are discussed. The outcome of this review may provide valuable information to future studies regarding cancer urinary VOCs.
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Key Words
- Biomarkers
- CAS, chemical abstracts service
- CYP450, cytochrome P450
- Cancer
- FAIMS, high-field asymmetric waveform ion mobility spectrometry
- GC, gas chromatography
- HS, headspace
- IMS, ion mobility spectrometry
- LC, liquid chromatography
- MS, mass spectrometry or mass spectrometric
- Mass Spectrometry
- Metabolomics
- NT, needle trap
- PSA, prostate-specific antigen
- PTR, proton transfer reaction
- PTV, programed temperature vaporizer
- ROS, reactive oxygen species
- SBSE, stir bar sorptive extraction
- SIFT, selected ion flow tube
- SPME, solid phase microextraction
- Urine
- VOCs
- VOCs, volatile organic compounds
- eNose, electronic nose
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Combustion in the future: The importance of chemistry. PROCEEDINGS OF THE COMBUSTION INSTITUTE. INTERNATIONAL SYMPOSIUM ON COMBUSTION 2020; 38:S1540-7489(20)30501-0. [PMID: 33013234 PMCID: PMC7518234 DOI: 10.1016/j.proci.2020.06.375] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 05/18/2020] [Accepted: 06/28/2020] [Indexed: 06/11/2023]
Abstract
Combustion involves chemical reactions that are often highly exothermic. Combustion systems utilize the energy of chemical compounds released during this reactive process for transportation, to generate electric power, or to provide heat for various applications. Chemistry and combustion are interlinked in several ways. The outcome of a combustion process in terms of its energy and material balance, regarding the delivery of useful work as well as the generation of harmful emissions, depends sensitively on the molecular nature of the respective fuel. The design of efficient, low-emission combustion processes in compliance with air quality and climate goals suggests a closer inspection of the molecular properties and reactions of conventional, bio-derived, and synthetic fuels. Information about flammability, reaction intensity, and potentially hazardous combustion by-products is important also for safety considerations. Moreover, some of the compounds that serve as fuels can assume important roles in chemical energy storage and conversion. Combustion processes can furthermore be used to synthesize materials with attractive properties. A systematic understanding of the combustion behavior thus demands chemical knowledge. Desirable information includes properties of the thermodynamic states before and after the combustion reactions and relevant details about the dynamic processes that occur during the reactive transformations from the fuel and oxidizer to the products under the given boundary conditions. Combustion systems can be described, tailored, and improved by taking chemical knowledge into account. Combining theory, experiment, model development, simulation, and a systematic analysis of uncertainties enables qualitative or even quantitative predictions for many combustion situations of practical relevance. This article can highlight only a few of the numerous investigations on chemical processes for combustion and combustion-related science and applications, with a main focus on gas-phase reaction systems. It attempts to provide a snapshot of recent progress and a guide to exciting opportunities that drive such research beyond fossil combustion.
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Key Words
- 2M2B, 2-methyl-2-butene
- AFM, atomic force microscopy
- ALS, Advanced Light Source
- APCI, atmospheric pressure chemical ionization
- ARAS, atomic resonance absorption spectroscopy
- ATcT, Active Thermochemical Tables
- BC, black carbon
- BEV, battery electric vehicle
- BTL, biomass-to-liquid
- Biofuels
- CA, crank angle
- CCS, carbon capture and storage
- CEAS, cavity-enhanced absorption spectroscopy
- CFD, computational fluid dynamics
- CI, compression ignition
- CRDS, cavity ring-down spectroscopy
- CTL, coal-to-liquid
- Combustion
- Combustion chemistry
- Combustion diagnostics
- Combustion kinetics
- Combustion modeling
- Combustion synthesis
- DBE, di-n-butyl ether
- DCN, derived cetane number
- DEE, diethyl ether
- DFT, density functional theory
- DFWM, degenerate four-wave mixing
- DMC, dimethyl carbonate
- DME, dimethyl ether
- DMM, dimethoxy methane
- DRIFTS, diffuse reflectance infrared Fourier transform spectroscopy
- EGR, exhaust gas recirculation
- EI, electron ionization
- Emissions
- Energy
- Energy conversion
- FC, fuel cell
- FCEV, fuel cell electric vehicle
- FRET, fluorescence resonance energy transfer
- FT, Fischer-Tropsch
- FTIR, Fourier-transform infrared
- Fuels
- GC, gas chromatography
- GHG, greenhouse gas
- GTL, gas-to-liquid
- GW, global warming
- HAB, height above the burner
- HACA, hydrogen abstraction acetylene addition
- HCCI, homogeneous charge compression ignition
- HFO, heavy fuel oil
- HRTEM, high-resolution transmission electron microscopy
- IC, internal combustion
- ICEV, internal combustion engine vehicle
- IE, ionization energy
- IPCC, Intergovernmental Panel on Climate Change
- IR, infrared
- JSR, jet-stirred reactor
- KDE, kernel density estimation
- KHP, ketohydroperoxide
- LCA, lifecycle analysis
- LH2, liquid hydrogen
- LIF, laser-induced fluorescence
- LIGS, laser-induced grating spectroscopy
- LII, laser-induced incandescence
- LNG, liquefied natural gas
- LOHC, liquid organic hydrogen carrier
- LT, low-temperature
- LTC, low-temperature combustion
- MBMS, molecular-beam MS
- MDO, marine diesel oil
- MS, mass spectrometry
- MTO, methanol-to-olefins
- MVK, methyl vinyl ketone
- NOx, nitrogen oxides
- NTC, negative temperature coefficient
- OME, oxymethylene ether
- OTMS, Orbitrap MS
- PACT, predictive automated computational thermochemistry
- PAH, polycyclic aromatic hydrocarbon
- PDF, probability density function
- PEM, polymer electrolyte membrane
- PEPICO, photoelectron photoion coincidence
- PES, photoelectron spectrum/spectra
- PFR, plug-flow reactor
- PI, photoionization
- PIE, photoionization efficiency
- PIV, particle imaging velocimetry
- PLIF, planar laser-induced fluorescence
- PM, particulate matter
- PM10 PM2,5, sampled fractions with sizes up to ∼10 and ∼2,5 µm
- PRF, primary reference fuel
- QCL, quantum cascade laser
- RCCI, reactivity-controlled compression ignition
- RCM, rapid compression machine
- REMPI, resonance-enhanced multi-photon ionization
- RMG, reaction mechanism generator
- RON, research octane number
- Reaction mechanisms
- SI, spark ignition
- SIMS, secondary ion mass spectrometry
- SNG, synthetic natural gas
- SNR, signal-to-noise ratio
- SOA, secondary organic aerosol
- SOEC, solid-oxide electrolysis cell
- SOFC, solid-oxide fuel cell
- SOx, sulfur oxides
- STM, scanning tunneling microscopy
- SVO, straight vegetable oil
- Synthetic fuels
- TDLAS, tunable diode laser absorption spectroscopy
- TOF-MS, time-of-flight MS
- TPES, threshold photoelectron spectrum/spectra
- TPRF, toluene primary reference fuel
- TSI, threshold sooting index
- TiRe-LII, time-resolved LII
- UFP, ultrafine particle
- VOC, volatile organic compound
- VUV, vacuum ultraviolet
- WLTP, Worldwide Harmonized Light Vehicle Test Procedure
- XAS, X-ray absorption spectroscopy
- YSI, yield sooting index
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An incidental finding in newborn screening leading to the diagnosis of a patient with ECHS1 mutations. Mol Genet Metab Rep 2020; 22:100553. [PMID: 31908952 PMCID: PMC6940607 DOI: 10.1016/j.ymgmr.2019.100553] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 12/27/2022] Open
Abstract
Short-chain enoyl-CoA hydratase (ECHS1) is a mitochondrial beta-oxidation enzyme involved in the metabolism of acyl-CoA fatty acid esters, as well as in valine metabolism. ECHS1 deficiency has multiple manifestations, including Leigh syndrome early at birth or in childhood with poor prognosis, to cutis laxa, exercise-induced dystonia and congenital lactic acidosis. Here we describe the case of a newborn with mutations in ECHS1 that caught our attention after the incidental finding of 3-hydroxy-butyryl\3-hydroxy-isobutyryl\malonylcarnitine (C4OH\C3DC) and tiglylcarnitine (C5:1) on blood spot in the newborn screening (NBS) program. Diagnosis was suspected based on the analysis of organic acids on dried urine spot. A moderate increase of 2-methyl-2,3-dihydroxybutyric acid, was detected, which is a known marker of this disease. Exome analysis showed c.404A>G (p.Asn135Ser) mutation in homozygosis in the ECHS1 gene. The child was therefore admitted to the hospital. Initial examination showed little response to auditory stimuli and mild hypertonia of the extremities. Clinical deterioration was evident at 4 months of age, including neurological and cardiac involvement, and the patient died at 5 months of age. This case illustrates how an incidental detection in the NBS Program can lead to the diagnosis ECHS1 deficiency. Although it is a severe disease, with no treatment available, early detection would allow adequate genetic counseling avoiding the odyssey that suffered most of these families.
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Key Words
- 2-methyl-2,3-dihydroxybutyric acid
- 3-hydroxy-butyrylcarnitine\3-hydoxy-isobutyrylcarnitine
- 3MGA, 3-methylglutaconic acid
- C3DC, malonylcarnitine
- C4OH, 3-hydroxy-butyrylcarnitine\3-hydoxy-isobutyrylcarnitine
- C5:1, tiglylcarnitine
- DBS, dried blood spot
- DUS, dried urine spot
- ECHS1 deficiency
- ECHS1, short-chain enoyl-CoA hydratase
- GC, gas chromatography
- HIBCH, 3-hydroxy-isobutyryl-CoA hydrolase
- MRI, magnetic resonance imaging
- MS, mass spectrometry
- Mutations in ECHS1
- NBS, Newborn Screening
- Newborn screening
- PDH, pyruvate dehydrogenase
- TMS, trimethylsilyl
- Tiglylcarnitine
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Comparison of monoamine oxidase inhibition by cigarettes and modified risk tobacco products. Toxicol Rep 2019; 6:1206-1215. [PMID: 31768332 PMCID: PMC6872813 DOI: 10.1016/j.toxrep.2019.11.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 11/07/2019] [Accepted: 11/11/2019] [Indexed: 10/30/2022] Open
Abstract
The adverse effects of cigarette smoking are well documented, and the two main strategies for reducing smoking prevalence are prevention of smoking initiation and promotion of smoking cessation. More recently, a third and complementary avenue, tobacco harm reduction has emerged, which is aimed to reduce the burden of smoking-related diseases. This has been enabled by the development of novel products such as electronic cigarettes (e-cigarettes) and heated tobacco products, designed to deliver nicotine with significantly reduced levels of the toxicants that are emitted by cigarettes. Several potential modified risk tobacco products (pMRTP) have been reported to emit significantly less toxicants than cigarettes and significantly reduce toxicant exposure in smokers who switch completely to such products. These are two prerequisites for pMRTPs to reduce harm and the risk of smoking-related disease. However, concerns remain regarding the addictive nature of these products. Smoking addiction is a complex phenomenon involving multiple pharmacological and non-pharmacological factors. Although the main pharmacological substance associated with smoking addiction is nicotine, accumulating evidence suggests that nicotine mostly acts as a primary reinforcer and that other factors are involved in establishing smoking addiction. Inhibition of monoamine oxidases (MAO)-mammalian flavoenzymes with a central role in neurotransmitter metabolism-has also been suggested to be involved in this process. Therefore, we aimed to comparatively investigate the ability of several types of pMRTPs and cigarette smoke (3R4F) to inhibit MAO activity. The results showed that the heated tobacco product Tobacco Heating System (THS) 2.2 and the MESH 1.1 e-cigarette possessed no MAO inhibitory activity while 3R4F significantly inhibits the levels of MAO activity (3R4F MAO-A and B; > 2 μM nicotine). Snus products have similar inhibition profiles as 3R4F but for larger nicotine concentrations (snus MAO-A; ∼68-fold, snus MAO-B; ∼23-fold higher compared to 3R4F). These observations were confirmed by analytical datasets of potential MAO inhibitors emitted by these products. In conclusion, we have demonstrated that specific pMRTPs, namely THS 2.2 and MESH 1.1, have a significantly lower MAO-inhibitory activity than 3R4F. These findings provide a basis for further investigation of the role of MAO inhibitors in cigarette addiction as well as the implications of the findings for abuse liability of pMRTPs in comparison with cigarettes.
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Key Words
- 3R4F, reference cigarette
- CRP, CORESTA Reference Product
- CS, cigarette smoke
- DMSO, dimethyl sulfoxide
- E-cigarettes
- FID, flame ionization detection
- GC, gas chromatography
- GCW, General Classic White
- GVP, gas–vapor phase
- Harm reduction
- IC50, half maximal inhibitory concentrations
- Ki, Inhibition Constant
- Km, Michaelis constant
- MAO, monoamine oxidases
- MESH, electronic cigarette
- Monoamine oxidase
- PBS, phosphate-buffered saline
- PMI, Philip Morris International
- PREP, potential reduced exposure products
- RT, room temperature
- Snus
- THS, Tobacco Heating System
- TPM, total particulate matter (TPM)
- Tobacco heating system
- cDNA, complementary DNA
- pMRTP, potential modified risk tobacco products
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Abstract
Metabolic profiling, metabonomics and metabolomics are terms coined in the late 1990s as they emerged as the newest 'omics' technology at the time. This line of research enquiry uses spectroscopic analytical platforms, which are mainly nuclear magnetic resonance spectroscopy and mass spectrometry (MS), to acquire a snapshot of metabolites, the end products of a complex biological system. Metabolic profiling enables the detection, quantification and characterisation of metabolites in biofluids, cells and tissues. The source of these compounds can be of endogenous, microbial or exogenous origin, such as dietary or xenobiotic. This results in generating extensive, multivariate spectroscopic data that require specific statistical manipulation, typically performed using chemometric and pattern recognition techniques to reduce its dimensions, facilitate its biological interpretation and allow sample classification and biomarker discovery. Consequently, it is possible to study the dynamic metabolic changes in response to disease, intervention or environmental conditions. In this review, we describe the fundamentals of MS so that clinicians can be literate in the field and are able to interrogate the right scientific questions.
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Key Words
- CID, collision-induced dissociation
- DC, direct current
- ESI, electrospray ionisation
- FC, fold change
- GC, gas chromatography
- HILIC, hydrophilic interaction liquid chromatography
- LC, liquid chromatography
- MS, mass spectrometry
- MWA, metabolome-wide association
- NMR, nuclear magnetic resonance
- OPLS-DA, orthogonal partial least squared-discriminant analysis
- PC, principal component
- PCA, principal components analysis
- Q-TOF, quadrupole coupled with time-of-flight
- RF, radio frequency
- RP, reversed-phase
- UPLC, ultra-performance liquid chromatography
- VIP, variable importance of projection
- mass spectroscopy
- mass-charge ratio
- metabolic profiling
- metabolomics
- targeted profiling
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Simultaneous biosynthesis of ( R)-acetoin and ethylene glycol from D-xylose through in vitro metabolic engineering. Metab Eng Commun 2018; 7:e00074. [PMID: 30197863 PMCID: PMC6127078 DOI: 10.1016/j.mec.2018.e00074] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/18/2018] [Accepted: 06/24/2018] [Indexed: 11/28/2022] Open
Abstract
(R)-acetoin is a four-carbon platform compound used as the precursor for synthesizing novel optically active materials. Ethylene glycol (EG) is a large-volume two-carbon commodity chemical used as the anti-freezing agent and building-block molecule for various polymers. Currently established microbial fermentation processes for converting monosaccharides to either (R)-acetoin or EG are plagued by the formation of undesirable by-products. We show here that a cell-free bioreaction scheme can generate enantiomerically pure acetoin and EG as co-products from biomass-derived D-xylose. The seven-step, ATP-free system included in situ cofactor regeneration and recruited enzymes from Escherichia coli W3110, Bacillus subtilis shaijiu 32 and Caulobacter crescentus CB 2. Optimized in vitro biocatalytic conditions generated 3.2 mM (R)-acetoin with stereoisomeric purity of 99.5% from 10 mM D-xylose at 30 °C and pH 7.5 after 24 h, with an initial (R)-acetoin productivity of 1.0 mM/h. Concomitantly, EG was produced at 5.5 mM, with an initial productivity of 1.7 mM/h. This in vitro biocatalytic platform illustrates the potential for production of multiple value-added biomolecules from biomass-based sugars with no ATP requirement.
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Key Words
- (R)-acetoin
- BSA, bovine serum albumin
- Cofactor regeneration
- D-xylose
- EG, ethylene glycol
- EMP, Embden-Meyerhoff-Parnas
- Ethylene glycol
- FAD, flavin adenine dinucleotide
- GC, gas chromatography
- HPLC, high-pressure liquid chromatography
- IPTG, isopropyl-β-D-thiogalactopyranoside
- In vitro metabolic engineering
- LB, lysogeny broth
- NAD+, oxidized nicotinamide adenine dinucleotide
- NADH, reduced nicotinamide adenine dinucleotide
- PET, polyethylene terephthalate
- PP, pentose phosphate
- SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis
- ThDP, Thiamine diphosphate
- ee, enantiomeric excess
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Data on volatile compounds produced by serotype D Clostridium botulinum. Data Brief 2018; 19:393-397. [PMID: 29900335 PMCID: PMC5997912 DOI: 10.1016/j.dib.2018.05.057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/08/2018] [Accepted: 05/10/2018] [Indexed: 11/28/2022] Open
Abstract
We analyzed the volatile compounds produced by serotype D Clostridium botulinum (D-CB16) in trypticase peptone/yeast extract/glucose (TYG) medium using gas chromatography/mass spectrometry (GC/MS). The volatile compounds were captured by solid-phase microextraction and applied to GC/MS for separation and identification of the compounds in TYG medium with or without the cultivation of C. botulinum D-CB16. Thirty-five and 34 volatile compounds were identified in media without and with D-CB16 cultivation, respectively. Of the compounds identified in the medium with the strain, twenty-one were not detected in the original medium, indicating that these were produced by C. botulinum D-CB16.
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Losing Reproduction: Effect of High Temperature on Female Biochemical Composition and Egg Quality in a Freshwater Crustacean with Direct Development, the Red Cherry Shrimp, Neocaridina davidi (Decapoda, Atyidae). THE BIOLOGICAL BULLETIN 2018; 234:139-151. [PMID: 29949439 DOI: 10.1086/698266] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Maternal provisioning is particularly important in invertebrates with abbreviated development because large energy reserves must be provided for the developing embryo. In this context, the objective of the present study was to analyze in an aquatic invertebrate with direct development the effect of temperature on female biochemical composition and reserve allocation to maturing ovaries, which determine egg quality. A decapod crustacean, the freshwater shrimp Neocaridina davidi, was used as experimental model. Newly hatched juveniles were exposed to 28 °C or 33 °C. Females showed mature ovaries and spawned at 28 °C (control ovigerous females), but no ovigerous female was found at 33 °C. After a 200-day period, half of the females at 33 °C were transferred to 28 °C, where they rapidly showed mature ovaries and spawned (transferred ovigerous females). Ovigerous females and females that did not spawn at 28 °C (control non-ovigerous females) and at 33 °C (high-temperature non-ovigerous females) were sacrificed to determine their biochemical composition. The number, volume, weight, and biochemical composition of the eggs from transferred and control ovigerous females were also analyzed as indicators of their quality. Female biochemical composition was not influenced by temperature, because control and high-temperature non-ovigerous females had similar lipid, protein, and glycogen contents. However, ovarian maturation and spawning were inhibited at 33 °C, which indicates a negative effect of this temperature on nutrient transfer to the oocytes. This effect was rapidly reversed after females were moved to 28 °C; the eggs from control and transferred ovigerous females were of similar quality, except for a lower protein content in the latter. The present results provide valuable information on reserve allocation to reproduction under thermal stress.
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Key Words
- CNO, control non-ovigerous female
- COF, control ovigerous female
- DGC test, Di Rienzo, Guzmán, and Casanoves test
- DHA, docosahexaenoic acid
- EPA, eicosapentaenoic acid
- FA, fatty acid
- FAME, fatty acid methyl ester
- GC, gas chromatography
- HTNO, high-temperature non-ovigerous female
- HUFA, highly unsaturated fatty acid
- LIN, linoleic acid
- MUFA, monounsaturated fatty acid
- PCA, principal component analysis
- PUFA, polyunsaturated fatty acid
- SFA, saturated fatty acid
- TOF, transferred ovigerous female
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Triterpenoid modulates the salt tolerance of lanosterol synthase deficient Saccharomyces cerevisiae, GIL77. Saudi J Biol Sci 2018; 25:1-9. [PMID: 29379348 PMCID: PMC5775075 DOI: 10.1016/j.sjbs.2016.10.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 08/05/2016] [Accepted: 10/12/2016] [Indexed: 11/30/2022] Open
Abstract
This study examined the effect of triterpenoid on the salt tolerance of lanosterol synthase deficient yeast mutant GIL77. The expression of the triterpenoid synthase gene under GAL1 promoter in GIL77 increased the triterpenoid concentration of both whole cell and plasma membrane fractions. Without the induction of the genes, the growth curve of BgbAS or RsM1 transformant depicted patterns similar to control cells in both the presence and absence of salt with growth inhibition at 500 mM NaCl. The induction of BgbAS and RsM1 gene expression slightly repressed growth compared with control cells in the absence of NaCl. The growth of GIL77 was significantly suppressed by the expression of BgbAS or RsM1 under salinity conditions. Of the triterpenoid synthase genes, BgbAS rather than RsM1 was found to strongly inhibit the growth of GIL77 cells under salt stressed conditions. The expression of the triterpenoid synthase gene in GIL77 also influenced their tolerance to other abiotic stresses. In contrast to the endogenous synthesis, the exogenous supply of triterpenoid in the culture medium appeared to occur in the plasma membrane fraction and enhanced the salt tolerance of GIL77. This study thus discussed the physiological significance of triterpenoid in relation to its possible role in modulating salt tolerance.
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Key Words
- BgLUS, lupeol synthase
- BgbAS, β-amyrin synthase
- FID, flame ionization detector
- GC, gas chromatography
- GIL77
- LS, lanosterol synthase
- MES, 2-morpholinoethanesulfonic acid
- OSCs, oxidosqualene cyclase
- Oxidosqualene cyclase gene
- RsM1, multifunctional triterpenoid synthase
- S.E.M., standard error of the mean
- SC, synthetic complete
- Salt tolerance
- TLC, thin layer chromatography
- Triterpenoids
- Yeast
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Volatile Biomarkers in Breath Associated With Liver Cirrhosis - Comparisons of Pre- and Post-liver Transplant Breath Samples. EBioMedicine 2015; 2:1243-50. [PMID: 26501124 PMCID: PMC4588000 DOI: 10.1016/j.ebiom.2015.07.027] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 07/17/2015] [Accepted: 07/20/2015] [Indexed: 12/15/2022] Open
Abstract
Background The burden of liver disease in the UK has risen dramatically and there is a need for improved diagnostics. Aims To determine which breath volatiles are associated with the cirrhotic liver and hence diagnostically useful. Methods A two-stage biomarker discovery procedure was used. Alveolar breath samples of 31 patients with cirrhosis and 30 healthy controls were mass spectrometrically analysed and compared (stage 1). 12 of these patients had their breath analysed after liver transplant (stage 2). Five patients were followed longitudinally as in-patients in the post-transplant period. Results Seven volatiles were elevated in the breath of patients versus controls. Of these, five showed statistically significant decrease post-transplant: limonene, methanol, 2-pentanone, 2-butanone and carbon disulfide. On an individual basis limonene has the best diagnostic capability (the area under a receiver operating characteristic curve (AUROC) is 0.91), but this is improved by combining methanol, 2-pentanone and limonene (AUROC curve 0.95). Following transplant, limonene shows wash-out characteristics. Conclusions Limonene, methanol and 2-pentanone are breath markers for a cirrhotic liver. This study raises the potential to investigate these volatiles as markers for early-stage liver disease. By monitoring the wash-out of limonene following transplant, graft liver function can be non-invasively assessed. Breath volatiles were compared for cirrhotic patients and controls and pre- and post-liver transplant. Three volatiles (limonene, methanol, 2-pentanone) have been found to have excellent diagnostic capabilities. Limonene shows washout characteristics following transplant supporting a hypothesis that it accumulates in fat.
There are numerous previous studies investigating breath volatiles in patients with liver disease but with conflicting results. It is impossible to tell which volatiles from previous studies may be false discoveries, and which are actually associated with the disease. We measured breath samples in patients and controls and in patients after transplant. Methanol, 2-pentanone and limonene show differences not only between patients and controls but also in cases pre- and post-transplant and have excellent diagnostic capabilities. We show evidence that limonene accumulates in the body, probably because the cirrhotic liver fails to metabolise dietary limonene.
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Key Words
- AID, autoimmune liver disease
- ALD, alcoholic liver disease
- AUROC, area under receiver operator curve
- BMI, body mass index
- Breath analysis
- CD, cryptogenic disease
- Cirrhosis
- Diagnosis limonene
- GC, gas chromatography
- HBV, hepatitis B virus
- HCC, hepatocellular cancer
- HCV, hepatitis C virus
- ITU, intensive treatment unit
- LQ, lower quartile
- Liver transplant
- MS, mass spectrometry
- OPU, out-patient clinic
- PBC, primary biliary cirrhosis
- PSC, primary sclerosing cholangitis
- PTR-MS
- PTR-MS, proton transfer reaction mass spectrometry
- ROC, Receiver operating characteristics
- TAC, transplant assessment clinic
- TE, transient elastography
- UKELD, United Kingdom model for end-stage liver disease
- UQ, upper quartile
- VMR, volume mixing ratio
- VOC, volatile organic compounds
- Volatile organic compounds
- ppbv, parts per billion by volume
- ppmv, parts per million by volume
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Analysis of ent-kaurenoic acid by ultra-performance liquid chromatography-tandem mass spectrometry. Biochem Biophys Rep 2015; 2:103-107. [PMID: 29124150 PMCID: PMC5668645 DOI: 10.1016/j.bbrep.2015.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 05/22/2015] [Accepted: 05/26/2015] [Indexed: 11/25/2022] Open
Abstract
ent-Kaurenoic acid (KA) is a key intermediate connected to a phytohormone gibberellin. To date, the general procedure for quantifying KA is by using traditional gas chromatography–mass spectrometry (GC–MS). In contrast, gibberellins, which are more hydrophilic than KA, can be easily quantified by liquid chromatography-tandem mass spectrometry (LC–MS/MS). In this study, we have established a new method to quantify KA by LC–MS/MS by taking advantage of a key feature of KA, namely the lack of fragmentation that occurs in MS/MS when electrospray ionization (ESI) is in the negative mode. Q1 and Q3 were adopted as identical channels for the multiple reaction monitoring of KA. The method was validated by comparing with the results obtained by selected ion monitoring in GC–MS. This new method could be applicable for the quantification of other hydrophobic compounds. ent-Kaurenoic acid (KA) can be quantified by LC–MS/MS. Detection limit of KA acid was 0.59 ng ml−1. We set Q1 and Q3 to the same MRM channel. Endogenous KA in a moss was detected and quantified.
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Key Words
- ESI, electrospray ionization
- GA, gibberellin
- GC, gas chromatography
- Gibberellin
- KA, ent-kaurenoic acid
- KAO, ent-kaurenoic acid oxidase
- KO, ent-kaurene oxidase
- LC, liquid chromatography
- LC–MS/MS
- LOD, limit of detection
- LOQ, limit of quantitation
- MRM
- MRM, multiple reaction monitoring
- MS/MS, tandem mass spectrometry
- Moss
- Phytoalexin
- SIM, selected ion monitoring
- ent-Kaurenoic acid
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Free radical derivatives formed from cyclooxygenase-catalyzed dihomo-γ-linolenic acid peroxidation can attenuate colon cancer cell growth and enhance 5-fluorouracil's cytotoxicity. Redox Biol 2014; 2:610-8. [PMID: 25114837 PMCID: PMC4124262 DOI: 10.1016/j.redox.2014.01.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 01/30/2014] [Indexed: 12/27/2022] Open
Abstract
Dihomo-γ-linolenic acid (DGLA) and its downstream fatty acid arachidonic acid (AA) are both nutritionally important ω-6 polyunsaturated fatty acids (ω-6s). Evidence shows that, via COX-mediated peroxidation, DGLA and its metabolites (1-series prostaglandins) are associated with anti-tumor activity, while AA and its metabolites (2-series prostaglandins) could be tightly implicated in various cancer diseases. However, it still remains a mystery why DGLA and AA possess contrasting bioactivities. Our previous studies showed that DGLA could go through an exclusive C-8 oxygenation pathway during COX-catalyzed lipid peroxidation in addition to a C-15 oxygenation pathway shared by both DGLA and AA, and that the exclusive C-8 oxygenation could lead to the production of distinct DGLA׳s free radical derivatives that may be correlated with DGLA׳s anti-proliferation activity. In the present work, we further investigate the anti-cancer effect of DGLA׳s free radical derivatives and their associated molecular mechanisms. Our study shows that the exclusive DGLA׳s free radical derivatives from C-8 oxygenation lead to cell growth inhibition, cell cycle arrest and apoptosis in the human colon cancer cell line HCA-7 colony 29, probably by up-regulating the cancer suppressor p53 and the cell cycle inhibitor p27. In addition, these exclusive radical derivatives were also able to enhance the efficacy of 5-Fluorouracil (5-FU), a widely used chemo-drug for colon cancer. For the first time, we show how DGLA׳s radical pathway and metabolites are associated with DGLA׳s anti-cancer activities and able to sensitize colon cancer cells to chemo-drugs such as 5-FU. Our findings could be used to guide future development of a combined chemotherapy and dietary care strategy for colon cancer treatment.
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Key Words
- 5-FU, 5-Fluorouracil
- 5-Fluorouracil
- 8-HOA, 8-hydroxyoctanoic acid
- AA, arachidonic acid
- ACN, acetonitrile
- COX, cyclooxygenase
- COX-catalyzed PUFA peroxidation
- Cell cycle and apoptosis
- Colon cancer cell line HCA-7 colony 29
- D5D, delta-5 desaturase
- DGLA, dihomo-γ-linoleic acid
- DGLA׳s free radical derivatives
- DHA, docosahexaenoic acid
- EIC, extracted ion chromatogram
- EPA, eicosapentaenoic acid
- ESR, electron spin resonance
- GC, gas chromatography
- HEX, 1-hexanol
- HOAc, glacial acetic acid
- HPLC/LC, high performance liquid chromatography
- HTA, heptanoic acid
- LC/MS and ESR spin trapping
- MS, mass spectrometry
- PGs, prostaglandins
- PI, propidium iodide
- POBN, α-[4-pyridyl-1-oxide]-N-tert-butyl nitrone
- PUFA, polyunsaturated fatty acid
- SPE, solid phase extraction
- TBS, Tris buffered saline
- TIC, total ion chromatogram
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Ectopic overexpression of castor bean LEAFY COTYLEDON2 (LEC2) in Arabidopsis triggers the expression of genes that encode regulators of seed maturation and oil body proteins in vegetative tissues. FEBS Open Bio 2013; 4:25-32. [PMID: 24363987 PMCID: PMC3863707 DOI: 10.1016/j.fob.2013.11.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 11/20/2013] [Accepted: 11/20/2013] [Indexed: 12/27/2022] Open
Abstract
The LEAFY COTYLEDON2 (LEC2) gene plays critically important regulatory roles during both early and late embryonic development. Here, we report the identification of the LEC2 gene from the castor bean plant (Ricinus communis), and characterize the effects of its overexpression on gene regulation and lipid metabolism in transgenic Arabidopsis plants. LEC2 exists as a single-copy gene in castor bean, is expressed predominantly in embryos, and encodes a protein with a conserved B3 domain, but different N- and C-terminal domains to those found in LEC2 from Arabidopsis. Ectopic overexpression of LEC2 from castor bean under the control of the cauliflower mosaic virus (CaMV) 35S promoter in Arabidopsis plants induces the accumulation of transcripts that encodes five major transcription factors (the LEAFY COTYLEDON1 (LEC1), LEAFY COTYLEDON1-LIKE (L1L), FUSCA3 (FUS3), and ABSCISIC ACID INSENSITIVE 3 (ABI3) transcripts for seed maturation, and WRINKELED1 (WRI1) transcripts for fatty acid biosynthesis), as well as OLEOSIN transcripts for the formation of oil bodies in vegetative tissues. Transgenic Arabidopsis plants that express the LEC2 gene from castor bean show a range of dose-dependent morphological phenotypes and effects on the expression of LEC2-regulated genes during seedling establishment and vegetative growth. Expression of castor bean LEC2 in Arabidopsis increased the expression of fatty acid elongase 1 (FAE1) and induced the accumulation of triacylglycerols, especially those containing the seed-specific fatty acid, eicosenoic acid (20:1Δ11), in vegetative tissues. Castor bean LEC2 is single copy and shows seed-specific expression. Over-expression of castor LEC2 induces genes involved in seed maturation in leaves. Castor LEC2 induces the accumulation of triacylglycerols and 20:1 fatty acids in leaves. Ectopic expression of castor LEC2 in Arabidopsis affects plant growth.
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Key Words
- ABI3-VP1, abscisic acid-insensitive 3-viviparous 1
- CaMV, cauliflower mosaic virus
- Castor bean
- DHA, docosahexaenoic acid
- DIG, digoxigenin
- Eicosenoic acid
- FAE1, fatty acid elongase 1
- GC, gas chromatography
- LEAFY COTYLEDON2
- ORF, open reading frame
- RT-PCR, reverse transcription polymerase chain reaction
- SSC, sodium chloride-sodium citrate
- Seed maturation
- TAG, triacylglycerol
- TF, transcription factor
- TLC, thin-layer chromatography
- Transcription factor
- Triacylglycerol
- cDNA, complementary DNA
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Estimation of BTEX in groundwater by using gas chromatography-mass spectrometry. Saudi J Biol Sci 2010; 17:205-8. [PMID: 23961078 DOI: 10.1016/j.sjbs.2010.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Accepted: 08/12/2009] [Indexed: 11/21/2022] Open
Abstract
Advanced analytical modern technology such as coupling a gas chromatography to a mass spectrometric technique provides sufficient information to the environmental and analytical chemists to identify the presence of a variety of components of the specific volatile organic product, determine the degree of the product weathering and in some instances estimate the age of the product as well in the testing sample. In this study, we estimated BTEX in groundwater sample by using gas chromatography-mass spectrometry (GC-MS) after standardization of this technique for advancement towards purification check of water samples in the petro-polluted regions of the soil.
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