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1

Comparative Analysis of PCRElectrospray Ionization/Mass Spectrometry (MS) and MALDI-TOF/MS for the  

E-print Network

-TOF/MS for the Identification of Bacteria and Yeast from Positive Blood Culture Bottles Erin J. Kaleta,1 Andrew E. Clark,2) for the semiquantitative analysis of microbial proteins and ge- netic elements. This study was performed to assess-ESI/MS and MALDI-TOF/MS in the ability to rapidly identify mi- croorganisms isolated from blood culture

Wysocki, Vicki H.

2

Analysis of Phospholipid Mixtures from Biological Tissues by Matrix-Assisted Laser Desorption and Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS): A Laboratory Experiment  

ERIC Educational Resources Information Center

Matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) is increasingly used to investigate the phospholipid (PL) compositions of tissues and body fluids, often without previous separation of the total mixture into the individual PL classes. Therefore, the questions of whether all PL classes are detectable…

Eibisch, Mandy; Fuchs, Beate; Schiller, Jurgen; Sub, Rosmarie; Teuber, Kristin

2011-01-01

3

Evaluation of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for species identification of bacteria of genera Arcanobacterium and Trueperella.  

PubMed

In the present study matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was evaluated for species identification of 98 bacteria previously classified phenotypically and genotypically to genera Arcanobacterium and Trueperella. Species identification was carried out by comparing the main spectra of each strain with the main spectra of reference strains of both genera and 3740 database entries included in the MALDI Biotyper 2.0 software package (Bruker Daltonik GmbH, Bremen, Germany). MALDI-TOF MS correctly identified (log (score) values ? 2.0) all investigated strains of the species A. (T.) bialowiezense (n=3), A. (T.) bonasi (n=7), A. haemolyticum (n=10), A. pluranimalium (n=1) and A. (T.) pyogenes (n=77). According to the present results MALDI-TOF MS had a comparable discriminating power than previously conducted tests on DNA level. Further studies with strains isolated from human infections would show the robustness of MALDI-TOF MS for identification of bacteria of these genera. PMID:22270885

Hijazin, M; Hassan, A A; Alber, J; Lämmler, C; Timke, M; Kostrzewa, M; Prenger-Berninghoff, E; Zschöck, M

2012-05-25

4

Protein Detection in Dried Blood by Surface-Enhanced Laser Desorption\\/Ionization-Time of Flight Mass Spectrometry (SELDI-TOF MS)  

Microsoft Academic Search

Background: The rapid and reliable identification of biomarkers in the smallest possible amount of blood remains a challenge in biomarker epidemiological research involving preterm newborns. Objective: We wanted to explore whether the proteomics approach of ‘surface-enhanced laser desorption\\/ionization-time of flight mass spectrometry’ (SELDI-TOF MS) is possible and feasible in whole cord blood previously dried on filter paper. Methods: Umbilical cord

Christiane E. L. Dammann; Markus Meyer; Olaf Dammann; Nils von Neuhoff

2006-01-01

5

Feasibility of matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) networking in university hospitals in Brussels.  

PubMed

The mutualisation of analytical platforms might be used to address rising healthcare costs. Our study aimed to evaluate the feasibility of networking a unique matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) system for common use in several university hospitals in Brussels, Belgium. During a one-month period, 1,055 successive bacterial isolates from the Brugmann University Hospital were identified on-site using conventional techniques; these same isolates were also identified using a MALDI-TOF MS system at the Porte de Hal Laboratory by sending target plates and identification projects via transportation and the INFECTIO_MALDI software (Infopartner, Nancy, France), respectively. The occurrence of transmission problems (<2 %) and human errors (<1 %) suggested that the system was sufficiently robust to be implemented in a network. With a median time-to-identification of 5 h and 11 min (78 min, min-max: 154-547), MALDI-TOF MS networking always provided a faster identification result than conventional techniques, except when chromogenic culture media and oxidase tests were used (p < 0.0001). However, the limited clinical benefits of the chromogenic culture media do not support their extra cost. Our financial analysis also suggested that MALDI-TOF MS networking could lead to substantial annual cost savings. MALDI-TOF MS networking presents many advantages, and few conventional techniques (optochin and oxidase tests) are required to ensure the same quality in patient care from the distant laboratory. Nevertheless, such networking should not be considered unless there is a reorganisation of workflow, efficient communication between teams, qualified technologists and a reliable IT department and helpdesk to manage potential connectivity problems. PMID:24197439

Martiny, D; Cremagnani, P; Gaillard, A; Miendje Deyi, V Y; Mascart, G; Ebraert, A; Attalibi, S; Dediste, A; Vandenberg, O

2014-05-01

6

Evaluation of two matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) systems for the identification of Candida species.  

PubMed

Candida spp. are responsible for severe infections in immunocompromised patients and those undergoing invasive procedures. The accurate identification of Candida species is important because emerging species can be associated with various antifungal susceptibility spectra. Conventional methods have been developed to identify the most common pathogens, but have often failed to identify uncommon species. Several studies have reported the efficiency of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the identification of clinically relevant Candida species. In this study, we evaluated two commercially available MALDI-TOF systems, Andromas™ and Bruker Biotyper™, for Candida identification in routine diagnosis. For this purpose, we investigated 1383 Candida isolates prospectively collected in eight hospital laboratories during routine practice. MALDI-TOF MS results were compared with those obtained using conventional phenotypic methods. Analysis of rDNA gene sequences with internal transcribed regions or D1-D2 regions is considered the reference standard for identification. Both MALDI-TOF MS systems could accurately identify 98.3% of the isolates at the species level (1359/1383 for Andromas™; 1360/1383 for Bruker Biotyper™) vs. 96.5% for conventional techniques. Furthermore, whereas conventional methods failed to identify rare or emerging species, these were correctly identified by MALDI-TOF MS. Both MALDI-TOF MS systems are accurate and cost-effective alternatives to conventional methods for mycological identification of clinically relevant Candida species and should improve the diagnosis of fungal infections as well as patient management. PMID:23594150

Lacroix, C; Gicquel, A; Sendid, B; Meyer, J; Accoceberry, I; François, N; Morio, F; Desoubeaux, G; Chandenier, J; Kauffmann-Lacroix, C; Hennequin, C; Guitard, J; Nassif, X; Bougnoux, M-E

2014-02-01

7

Identification of Arcanobacterium (Trueperella) abortisuis, a novel species of veterinary importance, by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS).  

PubMed

In the present study A. (T.) abortisuis isolated from pigs and bovines could be reliably identified by determination of phenotypic properties, genotypically by polymerase chain reaction with the help of A. (T.) abortisuis 16s-23S rDNA intergenic spacer region specific oligonucleotide primer and by Matrix-Assisted Laser Desorption Ionization-Time Of Flight mass spectrometry (MALDI-TOF MS). The latter appeared to be a promising tool for fast and cost effective identification of this species and might help to elucidate the role A. (T.) abortisuis plays in infections of pigs, bovines, possibly other animals or humans. PMID:22372322

Hijazin, Muaz; Ulbegi-Mohyla, Hivda; Alber, Jörg; Lämmler, Christoph; Hassan, Abdulwahed Ahmed; Timke, Markus; Kostrzewa, Markus; Prenger-Berninghoff, Ellen; Weiss, Reinhard; Zschöck, Michael

2012-01-01

8

Comprehensive multidimensional separation methods by hyphenation of single-photon ionization time-of-flight mass spectrometry (SPI-TOF-MS) with GC and GCxGC.  

PubMed

One- and comprehensive two-dimensional gas chromatography were hyphenated with soft photoionization mass spectrometry. The characteristics of these two- and three-dimensional comprehensive separation techniques are discussed in detail. Using the innovative electron beam pumped excimer light source (EBEL) for single-photon ionization (SPI), organic molecules with ionization energies (E ( i )) of below 9.8 eV can be detected by a time-of-flight mass spectrometer (TOF-MS). SPI with 126 nm vacuum ultraviolet (VUV) photons enables the universal and soft ionization of organic molecules. SPI-TOF-MS hyphenated to one-dimensional gas chromatography results in a comprehensive two-dimensional separation method (GCxMS). To demonstrate this, diesel fuel was analyzed, and the resulting GCxMS chromatograms are discussed in depth. A three-dimensional separation method was also realized by combining comprehensive two-dimensional gas chromatography (GCxGC) with SPI-MS. In the resulting separation space, constituents originating from mineral oil diesel blended with biodiesel were dispersed along the two GC separation axes, while the molecular mass axis served as a third separation dimension. PMID:20669008

Eschner, Markus S; Welthagen, Werner; Gröger, Thomas M; Gonin, Marc; Fuhrer, Katrin; Zimmermann, Ralf

2010-10-01

9

Analysis of rosin and modified rosin esters in adhesives by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS).  

PubMed

The optimum method for analyzing glyceryl rosinate by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was studied. The performances of dithranol, anthracene, and 2,5-dihydroxybenzoic acid, pyrene, trans,trans-1,4-diphenyl-1,3-butadiene, 9-nitroanthracene, indole-3-acrylic acid and retinoic acid as a matrix agent, and those of sodium trifluoroacetate (NaTFA) and silver trifluoroacetate (AgTFA) as a cationization agent were measured. Dithranol showed higher signal to noise ratio and lower base-line, and AgTFA showed better performance than NaTFA. In this study, however, NaTFA was chosen since the ester peaks with high signal to noise ratios were observed, and the spectra of sodium-cationized molecules are simpler than those of silver-cationized molecules. Rosin esters and modified rosin esters in 22 rubber-based pressure sensitive adhesives and a paper-cement were analyzed. Glyceryl rosinate, glyceryl disproportionated rosinate, pentaerythrityl rosinate and pentaerythrityl hydrogenated rosinate were easily detected despite the fact that rubber-based adhesives are complex mixtures of elastomers, tackifiers, antioxidants and other additives. The detection limit of this method was studied and 2% of glyceryl rosinate in a rubber-based pressure sensitive adhesive was detected. It has been proved that MALDI-TOF-MS is a useful analytical method to analyze rosin and modified rosin esters in adhesives. PMID:17728087

Kumooka, Y

2008-04-01

10

Gas chromatography time-of-flight mass spectrometry (GC-TOF-MS)-based metabolomics for comparison of caffeinated and decaffeinated coffee and its implications for Alzheimer's disease.  

PubMed

Findings from epidemiology, preclinical and clinical studies indicate that consumption of coffee could have beneficial effects against dementia and Alzheimer's disease (AD). The benefits appear to come from caffeinated coffee, but not decaffeinated coffee or pure caffeine itself. Therefore, the objective of this study was to use metabolomics approach to delineate the discriminant metabolites between caffeinated and decaffeinated coffee, which could have contributed to the observed therapeutic benefits. Gas chromatography time-of-flight mass spectrometry (GC-TOF-MS)-based metabolomics approach was employed to characterize the metabolic differences between caffeinated and decaffeinated coffee. Orthogonal partial least squares discriminant analysis (OPLS-DA) showed distinct separation between the two types of coffee (cumulative Q(2) = 0.998). A total of 69 discriminant metabolites were identified based on the OPLS-DA model, with 37 and 32 metabolites detected to be higher in caffeinated and decaffeinated coffee, respectively. These metabolites include several benzoate and cinnamate-derived phenolic compounds, organic acids, sugar, fatty acids, and amino acids. Our study successfully established GC-TOF-MS based metabolomics approach as a highly robust tool in discriminant analysis between caffeinated and decaffeinated coffee samples. Discriminant metabolites identified in this study are biologically relevant and provide valuable insights into therapeutic research of coffee against AD. Our data also hint at possible involvement of gut microbial metabolism to enhance therapeutic potential of coffee components, which represents an interesting area for future research. PMID:25098597

Chang, Kai Lun; Ho, Paul C

2014-01-01

11

Rapid Identification of Bacillus anthracis Spores in Suspicious Powder Samples by Using Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF MS)  

PubMed Central

Rapid and reliable identification of Bacillus anthracis spores in suspicious powders is important to mitigate the safety risks and economic burdens associated with such incidents. The aim of this study was to develop and validate a rapid and reliable laboratory-based matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) analysis method for identifying B. anthracis spores in suspicious powder samples. A reference library containing 22 different Bacillus sp. strains or hoax materials was constructed and coupled with a novel classification algorithm and standardized processing protocol for various powder samples. The method's limit of B. anthracis detection was determined to be 2.5 × 106 spores, equivalent to a 55-?g sample size of the crudest B. anthracis-containing powder discovered during the 2001 Amerithrax incidents. The end-to-end analysis method was able to successfully discriminate among samples containing B. anthracis spores, closely related Bacillus sp. spores, and commonly encountered hoax materials. No false-positive or -negative classifications of B. anthracis spores were observed, even when the analysis method was challenged with a wide range of other bacterial agents. The robustness of the method was demonstrated by analyzing samples (i) at an external facility using a different MALDI-TOF MS instrument, (ii) using an untrained operator, and (iii) using mixtures of Bacillus sp. spores and hoax materials. Taken together, the observed performance of the analysis method developed demonstrates its potential applicability as a rapid, specific, sensitive, robust, and cost-effective laboratory-based analysis tool for resolving incidents involving suspicious powders in less than 30 min. PMID:23811517

van der Laaken, Anton L.; Blatny, Janet Martha; Paauw, Armand

2013-01-01

12

Rapid identification of Bacillus anthracis spores in suspicious powder samples by using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS).  

PubMed

Rapid and reliable identification of Bacillus anthracis spores in suspicious powders is important to mitigate the safety risks and economic burdens associated with such incidents. The aim of this study was to develop and validate a rapid and reliable laboratory-based matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis method for identifying B. anthracis spores in suspicious powder samples. A reference library containing 22 different Bacillus sp. strains or hoax materials was constructed and coupled with a novel classification algorithm and standardized processing protocol for various powder samples. The method's limit of B. anthracis detection was determined to be 2.5 × 10(6) spores, equivalent to a 55-?g sample size of the crudest B. anthracis-containing powder discovered during the 2001 Amerithrax incidents. The end-to-end analysis method was able to successfully discriminate among samples containing B. anthracis spores, closely related Bacillus sp. spores, and commonly encountered hoax materials. No false-positive or -negative classifications of B. anthracis spores were observed, even when the analysis method was challenged with a wide range of other bacterial agents. The robustness of the method was demonstrated by analyzing samples (i) at an external facility using a different MALDI-TOF MS instrument, (ii) using an untrained operator, and (iii) using mixtures of Bacillus sp. spores and hoax materials. Taken together, the observed performance of the analysis method developed demonstrates its potential applicability as a rapid, specific, sensitive, robust, and cost-effective laboratory-based analysis tool for resolving incidents involving suspicious powders in less than 30 min. PMID:23811517

Dybwad, Marius; van der Laaken, Anton L; Blatny, Janet Martha; Paauw, Armand

2013-09-01

13

Multi-residue analysis method for analysis of pharmaceuticals using liquid chromatography-time of flight/mass spectrometry (LC-TOF/MS) in water sample  

NASA Astrophysics Data System (ADS)

In this work, a developed method using solid - phase extraction (SPE) followed by liquid chromatography - time of flight mass spectrometry (LC-ESI-TOF/MS) was developed and validated for quantification and confirmation of eleven pharmaceuticals with different therapeutic classes in water samples, Malaysia. These compounds are caffeine (CAF), prazosin (PRZ), enalapril (ENL), carbamazepine (CBZ), nifedipine (NFD), levonorgestrel (LNG), simvastatin (SMV), hydrochlorothiazide (HYD), gliclazide (GLIC), diclofenac-Na (DIC-Na) and mefenamic acid (MEF). LC was performed on a Dionex Ultimate 3000/LC 09115047 (USA) system. Chromatography was performed on a Thermo Scientific C18 (250 mm × 2.1 mm, i.d.: 5?m) column. Several parameters were optimised such as; mobile phase, gradient elution, collision energy and solvent elution for extraction of compounds from water. The recoveries obtained ranged from 30-148 % in river water. Five pharmaceutical compounds were detected in the surface water samples: caffeine, prazosin, enalpril, diclofenac-Na and mefenamic acid. The developed method is precise and accepted recoveries were got. In addition, this method is suitable to identify and quantify trace concentrations of pharmaceuticals in surface water.

Al-Qaim, Fouad Fadhil; Abdullah, Md Pauzi; Othman, Mohamed Rozali

2013-11-01

14

Rapid and highly accurate detection of steryl glycosides by ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS).  

PubMed

This study describes the development and validation of a fast, accurate, and precise UPLC-Q-TOF-MS method for the analysis of steryl glycosides (SGs). The best combination of separation and sensitivity was obtained with a methanol/water gradient and formic acid as additive, using electrospray ionization (ESI). SGs were detected almost exclusively as sodiated adducts, allowing identification of the intact molecule, including the sugar moiety. The TOF-MS system offered high mass accuracy (1.3 ppm), providing a valuable tool for SG identification. The method was used to quantify single SG species in oat bran and whole wheat, and it was demonstrated that reliable quantification requires accounting for the matrix effect, which may reduce the SG signal by up to 50% in some samples. The level of matrix effect also depends on food matrices with various SG contents, indicating that it should be individually considered for each sample. PMID:25175549

Oppliger, Selina R; Münger, Linda H; Nyström, Laura

2014-10-01

15

Detection of aqueous phase chemical warfare agent degradation products by negative mode ion mobility time-of-flight mass spectrometry [IM(tof)MS].  

PubMed

The use of negative ion monitoring mode with an atmospheric pressure ion mobility orthogonal reflector time-of-flight mass spectrometer [IM(tof)MS] to detect chemical warfare agent (CWA) degradation products from aqueous phase samples has been determined. Aqueous phase sampling used a traditional electrospray ionization (ESI) source for sample introduction and ionization. Certified reference materials (CRM) of CWA degradation products for the detection of Schedule 1, 2, or 3 toxic chemicals or their precursors as defined by the chemical warfare convention (CWC) treaty verification were used in this study. A mixture of six G-series nerve related CWA degradation products (EMPA, IMPA, EHEP, IHEP, CHMPA, and PMPA) and their related collision induced dissociation (CID) fragment ions (MPA and EPA) were found in each case to be clearly resolved and detected using the IM(tof)MS instrument in negative ion monitoring mode. Corresponding ions, masses, drift times, K(o) values, and signal intensities for each of the CWA degradation products are reported. PMID:16413205

Steiner, Wes E; Harden, Charles S; Hong, Feng; Klopsch, Steve J; Hill, Herbert H; McHugh, Vincent M

2006-02-01

16

Real-time analysis of aromatics in combustion engine exhaust by resonance-enhanced multiphoton ionisation time-of-flight mass spectrometry (REMPI-TOF-MS): a robust tool for chassis dynamometer testing.  

PubMed

Resonance-enhanced multiphoton ionisation time-of-flight mass spectrometry (REMPI-TOF-MS) is a robust method for real-time analysis of monocyclic and polycyclic aromatic hydrocarbons in complex emissions. A mobile system has been developed which enables direct analysis on site. In this paper, we utilize a multicomponent calibration scheme based on the analytes' photo-ionisation cross-sections relative to a calibrated species. This allows semi-quantification of a great number of components by only calibrating one compound of choice, here toluene. The cross-sections were determined by injecting nebulised solutions of aromatic compounds into the TOF-MS ion source with the help of a HPLC pump. Then, REMPI-TOF-MS was implemented at various chassis dynamometers and test cells and the exhaust of the following vehicles and engines investigated: a compression ignition light-duty (LD) passenger car, a compression ignition LD van, two spark ignition LD passenger cars, 2 two-stroke mopeds, and a two-stroke engine of a string gas trimmer. The quantitative time profiles of benzene are shown. The results indicate that two-stroke engines are a significant source for toxic and cancerogenic compounds. Air pollution and health effects caused by gardening equipment might still be underestimated. PMID:22644155

Adam, T W; Clairotte, M; Streibel, T; Elsasser, M; Pommeres, A; Manfredi, U; Carriero, M; Martini, G; Sklorz, M; Krasenbrink, A; Astorga, C; Zimmermann, R

2012-07-01

17

Elucidation of riverine and lacustrine dissolved organic matter (DOM) composition using comprehensive GC×GC time-of-flight mass spectrometry (GC×GC-TOF-MS)  

NASA Astrophysics Data System (ADS)

Rivers and streams play a key role in mediating the transfer of organic carbon (both particulate and dissolved) from terrestrial to aquatic settings. Dissolved organic carbon represents the majority of the carbon pool in low alkalinity riverine and lacustrine waters, and its composition plays important roles, including affecting water clarity and stimulating heterotrophic productivity, which influences its rate of reconversion to CO2. Yet, the chemical complexity and heterogeneity of this reservoir have limited structural elucidation to primarily describing common bulk-level characteristics. Seasonal SPE-DOM samples from the Upper Truckee River, Lake Tahoe, and two surrounding lakes, as well as SPE-DOM isolated from two dissimilar California rivers, were first characterized using ?13C, ?15N, 1H-NMR, and then subjected to CuO oxidation followed by TMS derivatization and were analyzed using comprehensive GC×GC time-of-flight mass spectrometry (GC×GC-TOF-MS). Thousands of peaks were identified per sample. Simultaneous, orthogonal separation of components in two dimensions (on the basis of volatility and polarity) allowed for the identification of oxidation mixture components by both their MS spectra and, when MS spectra alone were insufficient for structural assignment and standards were absent, by the observed trajectories of homologues compound series assumed in 2-D retention-time space. Several homologous compound series were observed, including mid-to-long chain fatty acids, keto (?-1) fatty acids, (?, ?)-dioic acids, and the resolution and identification of closely related isomers, such as the benzene di-, and tricarboxylic acids, were also facilitated by this method. Furthermore, in mixed samples containing two or more end-members, such as in lake DOM samples characterized by mixed terrestrial and algal OM sources, the intensity of the phenolic elution space, which includes the lignin phenols and lignin phenolic dimers, correlates with ancillary measurements indicative of terrestrial OM loading, such as increased 1H-NMR resonance intensities for methoxy and aromatic-linked hydrogens and lower ?13C values more consistent with C3 plant versus algal sources.igure 1: Oxidized and derivatized SPE-DOM isolated from the Upper Truckee River, South Lake Tahoe, CA, and visualized in two dimensions.

Ball, G. I.; Goldberg, S. J.; Aluwihare, L. I.

2012-12-01

18

Sensomics analysis of key hazelnut odorants (Corylus avellana L. 'Tonda Gentile') using comprehensive two-dimensional gas chromatography in combination with time-of-flight mass spectrometry (GC×GC-TOF-MS).  

PubMed

Comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) has been used a few times to identify and quantitate single aroma-active compounds, but the capability of this technique to monitor a complete set of key odorants evoking the aroma of a given food in one run has not been exploited so far. A fast, multiodorant analysis using GC×GC-TOF-MS in combination with stable isotope dilution assays (SIDA) was developed to quantitate the entire set of aroma compounds, the sensometabolome, of raw and roasted hazelnuts ( Corylus avellana L. 'Tonda Gentile') previously established by GC-olfactometry. The capability of the method to evaluate the aroma contribution of each sensometabolite was evaluated by introducing a new term, the limit of odor activity value (LOAV), indicating whether a given aroma compound can be determined down to an odor activity value (OAV) of 1 (odor activity value = ratio of concentration to odor threshold). The advantage of the new method was proven by comparing the performance parameters with a traditional one-dimensional approach using GC-ion trap mass-spectrometry (GC-IT-MS). The results showed that the detector linearity and sensitivity of GC×GC-TOF-MS was on average higher by a factor of 10 compared to GC-IT-MS, thus enabling the quantitation of the aroma relevant amounts of 22 key odorants of hazelnuts in one run of the 30 aroma-active compounds. Seven novel isotopically labeled internal standards were synthesized to meet the analytical requirements defined by electron impact ionization in TOF-MS, that is, to keep the label. On the basis of the quantitative results obtained, it was possible to closely mimic the aroma of raw and roasted 'Tonda Gentile' hazelnuts by preparing an aroma recombinate containing the key odorants at their natural concentrations occurring in the nuts. PMID:23663170

Kiefl, Johannes; Pollner, Gwendola; Schieberle, Peter

2013-06-01

19

Gas Chromatography Time-Of-Flight Mass Spectrometry (GC-TOF-MS)-Based Metabolomics for Comparison of Caffeinated and Decaffeinated Coffee and Its Implications for Alzheimer’s Disease  

PubMed Central

Findings from epidemiology, preclinical and clinical studies indicate that consumption of coffee could have beneficial effects against dementia and Alzheimer’s disease (AD). The benefits appear to come from caffeinated coffee, but not decaffeinated coffee or pure caffeine itself. Therefore, the objective of this study was to use metabolomics approach to delineate the discriminant metabolites between caffeinated and decaffeinated coffee, which could have contributed to the observed therapeutic benefits. Gas chromatography time-of-flight mass spectrometry (GC-TOF-MS)-based metabolomics approach was employed to characterize the metabolic differences between caffeinated and decaffeinated coffee. Orthogonal partial least squares discriminant analysis (OPLS-DA) showed distinct separation between the two types of coffee (cumulative Q2?=?0.998). A total of 69 discriminant metabolites were identified based on the OPLS-DA model, with 37 and 32 metabolites detected to be higher in caffeinated and decaffeinated coffee, respectively. These metabolites include several benzoate and cinnamate-derived phenolic compounds, organic acids, sugar, fatty acids, and amino acids. Our study successfully established GC-TOF-MS based metabolomics approach as a highly robust tool in discriminant analysis between caffeinated and decaffeinated coffee samples. Discriminant metabolites identified in this study are biologically relevant and provide valuable insights into therapeutic research of coffee against AD. Our data also hint at possible involvement of gut microbial metabolism to enhance therapeutic potential of coffee components, which represents an interesting area for future research. PMID:25098597

Chang, Kai Lun; Ho, Paul C.

2014-01-01

20

Source-Identifying Biomarker Ions between Environmental and Clinical Burkholderia pseudomallei Using Whole-Cell Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS)  

PubMed Central

Burkholderia pseudomallei is the causative agent of melioidosis, which is an endemic disease in Northeast Thailand and Northern Australia. Environmental reservoirs, including wet soils and muddy water, serve as the major sources for contributing bacterial infection to both humans and animals. The whole-cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (whole-cell MALDI-TOF MS) has recently been applied as a rapid, accurate, and high-throughput tool for clinical diagnosis and microbiological research. In this present study, we employed a whole-cell MALDI-TOF MS approach for assessing its potency in clustering a total of 11 different B. pseudomallei isolates (consisting of 5 environmental and 6 clinical isolates) with respect to their origins and to further investigate the source-identifying biomarker ions belonging to each bacterial group. The cluster analysis demonstrated that six out of eleven isolates were grouped correctly to their sources. Our results revealed a total of ten source-identifying biomarker ions, which exhibited statistically significant differences in peak intensity between average environmental and clinical mass spectra using ClinProTools software. Six out of ten mass ions were assigned as environmental-identifying biomarker ions (EIBIs), including, m/z 4,056, 4,214, 5,814, 7,545, 7,895, and 8,112, whereas the remaining four mass ions were defined as clinical-identifying biomarker ions (CIBIs) consisting of m/z 3,658, 6,322, 7,035, and 7,984. Hence, our findings represented, for the first time, the source-specific biomarkers of environmental and clinical B. pseudomallei. PMID:24914956

Srisanga, Kitima; Roytrakul, Sittiruk; Tungpradabkul, Sumalee

2014-01-01

21

Analytical capabilities of inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry (ICP-oa-TOF-MS) for multi-element analysis of food and beverages.  

PubMed

Analytical capabilities of ICP-oa-TOF-MS for rapid, simultaneous and reliable determination of more than 50 major, trace and ultra-trace elements in different food and beverages samples (milk and dairy based products, cereals, meat, offal, sugar and sugar products, potatoes, fats, baby food samples, fruit juices, alcoholic beverages), following microwave closed vessel digestion of samples, were described. Under optimum instrumental conditions, and by using Rh as an internal standard and an external calibration method, ICP-oa-TOF-MS enables an accurate analysis, taking about one minute per a sample for all elements and isotopes of interest even for some elements such Zn, Ni, Cu, As or Co whose assay is more difficult when using conventional quadrupole instruments. In order to verify the accuracy and precision of the proposed method, 8 commercially available reference materials representing 3 major groups of food (milk and dairy based products, meat, cereals) were analysed, yielding results in agreement with certified values and the precision bellow 15%. In addition, accuracy was confirmed by spiked analytical recoveries study and accurate isotopic ratio determinations with the precision typically better than 5% with 5s data acquisition period, also for other elements of interest whose content was not certified and different sample matrices. Limits of detection (3?) have varied from 0.04ngg(-1) for Th to 1630ngg(-1) for Ca. PMID:25212369

Husáková, Lenka; Urbanová, Iva; Srámková, Jitka; Cernohorský, Tomáš; Krej?ová, Anna; Bedna?íková, Marie; Frýdová, Eva; Ned?lková, Iva; Pila?ová, Lucie

2011-12-01

22

Fecal metabonomic study of a polysaccharide, MDG-1 from Ophiopogon japonicus on diabetic mice based on gas chromatography/time-of-flight mass spectrometry (GC TOF/MS).  

PubMed

Type 2 Diabetes Mellitus (T2DM) is a chronic metabolic disorder with systemic complications and has been a worldwide epidemic. Ophiopogon japonicus is a traditional Chinese medicine used to treat diabetes for thousands of years. From our previous work, we know that MDG-1, a water-soluble ?-D-fructan polysaccharide from O. japonicas could treat T2DM experimentally. However, MDG-1 is poorly absorbed and its mechanism of action is still unknown. Therefore, a GC TOF/MS-based metabonomic approach in combination with multivariate statistical analysis was performed to investigate the mechanism of MDG-1 in a spontaneous diabetic model. Female diabetic KKay mice (21 weeks old) were randomly divided into a diabetic group (n = 6, gavaged with distilled water) and a MDG-1-Diabetic group (n = 7, gavaged with MDG-1, 300 mg kg(-1)) and female C57BL/6 mice (21 weeks old) were set as controls (n = 6, gavaged with distilled water). After 8-weeks of treatment, feces samples were collected for GC-TOF/MS analysis. Consequently, 12 potential biomarkers were identified, including monosugars (D-tagatose, D-lyxose, D-erythrose, xylo-hexos-5-ulose, 2-deoxy-galactose), butanedioic acid, amino acids (phenylalanine, L-lysine, L-methionine, L-aspartic acid) and purine derivatives (7H-purine, 2'-deoxyinosine). We assume the monosugars and butanedioic acid were the fermentation products of MDG-1 by intestinal microbes and MDG-1 actions against diabetes might be accomplished through the absorbable monosugars and butanedioic acid via suppressing intestinal glucose absorption, enhancing liver glycogenesis, inhibiting glycogenolysis and promoting GLP-1 secretion. Besides, MDG-1 might alleviate diabetes and diabetic nephropathy by reducing 7H-purine and 2'-deoxyinosine. Further omics-driven studies including genomics, proteomics and metabonomics were considered to be carried out to provide direct evidence of gut microbiome contribution to MDG-1 actions. PMID:24292023

Zhu, Yunyun; Cong, Wenjuan; Shen, Lan; Wei, Hai; Wang, Yuan; Wang, Lingyi; Ruan, Kefeng; Wu, Fei; Feng, Yi

2014-02-01

23

Algorithm for locating analytes of interest based on mass spectral similarity in GC × GC–TOF-MS data: analysis of metabolites in human infant urine  

Microsoft Academic Search

The developed algorithm reported herein, referred to as “DotMap,” addresses the need to rapidly identify analyte peak locations in gas chromatography × gas chromatography–time of flight mass spectrometry (GC × GC–TOF-MS) data. The third-order structure of GC × GC–TOF-MS data is such that at each point in the GC × GC chromatogram, a complete mass spectrum is measured. DotMap utilizes

Amanda E. Sinha; Janiece L. Hope; Bryan J. Prazen; Erik J. Nilsson; Rhona M. Jack; Robert E. Synovec

2004-01-01

24

Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/MS)-based identification of pathogens from positive blood culture bottles.  

PubMed

Since the expansion of commercial use of MALDI-TOF/MS instruments for the identification of bacteria from culture which has occurred over the past 5-8 years, techniques for the identification of bacteria directly from positive blood cultures have been developed (Lagace-Wiens et al., J Clin Microbiol 50:3324-3328, 2012; Martiny et al., Eur J Clin Microbiol Infect Dis 31:2269-2281, 2012; Moussaoui et al., Clin Microbiol Infect 16:1631-1638, 2010). These techniques have the potential to provide definitive identification of pathogens causing sepsis 18-48 h earlier than conventional methodologies, and implementation of these methods has been shown to impact morbidity and hospital costs in a positive way (Martiny et al., Clin Microbiol Infect 19:E568-E581, 2013; Loonen et al., Eur J Clin Microbiol Infect Dis 31:1575-1583, 2012). Although many methods for purification of bacterial cells have been developed, including differential centrifugation, centrifuge lysis, and preincubation on sold media (March-Rossello et al., Eur J Clin Microbiol Infect Dis 32:699-704, 2013; Saffert et al., Diagn Microbiol Infect Dis 73:21-26, 2012; Schubert et al., J Mol Diagn 13:701-706, 2011), we will describe the method by which intact bacterial cells are extracted from positive blood culture bottles using a commercially available kit (SepsiTyper™) which is based on the centrifuge lysis methodology (Lagace-Wiens et al., J Clin Microbiol 50:3324-3328, 2012; Buchan et al., J Clin Microbiol 50:346-352, 2012). PMID:25319778

Lagacé-Wiens, Philippe

2015-01-01

25

Interlaboratory reproducibility of fast gas chromatography–electron impact–time of flight mass spectrometry (GC–EI–TOF\\/MS) based plant metabolomics  

Microsoft Academic Search

The application of gas chromatography–mass spectrometry (GC–MS) to the ‘global’ analysis of metabolites in complex samples\\u000a (i.e. metabolomics) has now become routine. The generation of these data-rich profiles demands new strategies in data mining\\u000a and standardisation of experimental and reporting aspects across laboratories. As part of the META-PHOR project’s (METAbolomics\\u000a for Plants Health and OutReach: http:\\/\\/www.meta-phor.eu\\/) priorities towards robust technology

J. William Allwood; Alexander Erban; Sjaak de Koning; Warwick B. Dunn; Alexander Luedemann; Arjen Lommen; Lorraine Kay; Ralf Löscher; Joachim Kopka; Royston Goodacre

2009-01-01

26

Capillary zone electrophoresis (CZE) coupled to time-of-flight mass spectrometry (TOF-MS) applied to the analysis of illicit and controlled drugs in blood.  

PubMed

A new method for the determination of illicit and abused drugs in blood by capillary zone electrophoresis-electrospray ionization-time-of-flight mass spectrometry is proposed, in view of its application in clinical and forensic toxicology. The analytes (methamphetamine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylenedioxymethamphetamine, methadone, cocaine, morphine, codeine, 6-acethylmorphine, benzoylecgonine) were separated with capillary zone electrophoresis by applying 15 kV within 25 min, in an uncoated fused-silica capillary (75 microm x 100 cm) using a 25 mM ammonium formate electrolyte solution (pH 9.5). The capillary electropherograph was coupled to time-of-flight mass spectrometry through an orthogonal electrospray ionization source, with a coaxial sheath liquid interface. The sheath liquid was composed of isopropanol-water (1:1 v/v) containing 0.5% formic acid delivered at 4 microL/min. Forensic drugs were identified by exact mass determination (mass accuracy typically < or =5 ppm) and by matching of the isotopic pattern. Under optimized conditions, linearity was assessed in the range 10-2000 ng/mL, with correlation coefficients between 0.9744 and 0.9982 for all the analytes. LODs were in the range of 2-10 ng/mL (S/N > or =3) and LOQs of 10-30 ng/mL. The CVs (tested at 40 and 800 ng/mL in biological matrix) were below 2.97% for migration times and below 14.61% for peak area ratios (analyte/internal standard). Blood samples were extracted by using a liquid-liquid extraction procedure and injected under field-amplified sample stacking conditions. The method was successfully applied to real cases. PMID:18958878

Gottardo, Rossella; Polettini, Aldo; Sorio, Daniela; Pascali, Jennifer Paola; Bortolotti, Federica; Liotta, Eloisa; Tagliaro, Franco

2008-10-01

27

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for detection and identification of albumin phosphylation by organophosphorus pesticides and G- and V-type nerve agents.  

PubMed

Toxic organophosphorus compounds (OPC), e.g., pesticides and nerve agents (NA), are known to phosphylate distinct endogenous proteins in vivo and in vitro. OPC adducts of butyrylcholinesterase and albumin are considered to be valuable biomarkers for retrospective verification of OPC exposure. Therefore, we have detected and identified novel adducts of human serum albumin (HSA) by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Pure albumin and plasma were incubated with numerous pesticides and NA of the V- and G-type in different molar ratios. Samples were prepared either by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by in-gel enzymatic cleavage using endoproteinase Glu-C (Glu-C) or by combining highly albumin-selective affinity extraction with ultrafiltration followed by reduction, carbamidomethylation, and enzymatic cleavage (Glu-C) prior to MALDI-TOF MS analysis. Characteristic mass shifts for phosphylation revealed tyrosine adducts at Y(411) (Y(401)KFQNALLVRY(411)TKKVPQVSTPTLVE(425)), Y(148) and Y(150) (I(142)ARRHPY(148)FY(150)APE(153), single and double labeled), and Y(161) (L(154)LFFAKRY(161)KAAFTE(167)) produced by original NA (tabun, sarin, soman, cyclosarin, VX, Chinese VX, and Russian VX) as well as by chlorpyrifos-oxon, diisopropyl fluorophosphate (DFP), paraoxon-ethyl (POE), and profenofos. MALDI-MS/MS of the single-labeled I(142)-E(153) peptide demonstrated that Y(150) was phosphylated with preference to Y(148). Aged albumin adducts were not detected. The procedure described was reproducible and feasible for detection of adducts at the most reactive Y(411)-residue (S/N???3) when at least 1% of total albumin was labeled. This was achieved by incubating plasma with molar HSA/OPC ratios ranging from approximately 1:0.03 (all G-type NA, DFP, and POE) to 1:3 (V-type NA, profenofos). Relative signal intensity of the Y(411) adduct correlated well with the spotted relative molar amount underlining the usefulness for quantitative adduct determination. In conclusion, the current analytical design exhibits potential as a verification tool for high-dose exposure. PMID:20730528

John, Harald; Breyer, Felicitas; Thumfart, Jörg Oliver; Höchstetter, Hans; Thiermann, Horst

2010-11-01

28

Eddy covariance emission and deposition flux measurements using proton transfer reaction-time of flight-mass spectrometry (PTR-TOF-MS): comparison with PTR-MS measured vertical gradients and fluxes  

NASA Astrophysics Data System (ADS)

During summer 2010, a proton transfer reaction-time of flight-mass spectrometer (PTR-TOF-MS) and a standard proton transfer reaction mass spectrometer (PTR-MS) were deployed simultaneously for one month in an orange orchard in the Central Valley of California to collect continuous data suitable for eddy covariance (EC) flux calculations. The high time resolution (5 Hz) and high mass resolution (up to 5000 m ? m-1) data from the PTR-TOF-MS provided the basis for calculating the concentration and flux for a wide range of volatile organic compounds (VOC). Throughout the campaign, 664 mass peaks were detected in mass-to-charge ratios between 10 and 1278. Here we present PTR-TOF-MS EC fluxes of the 27 ion species for which the vertical gradient was simultaneously measured by PTR-MS. These EC flux data were validated through spectral analysis (i.e. co-spectrum, normalized co-spectrum, and ogive). Based on inter-comparison of the two PTR instruments, no significant instrumental biases were found in either mixing ratios or fluxes, and the data showed agreement within 5% on average for methanol and acetone. For the measured biogenic volatile organic compounds (BVOC), the EC fluxes from PTR-TOF-MS were in agreement with the qualitatively inferred flux directions from vertical gradient measurements by PTR-MS. For the 27 selected ion species reported here, the PTR-TOF-MS measured total (24 h) mean net flux of 299 ?g C m-2 h-1. The dominant BVOC emissions from this site were monoterpenes (m/z 81.070 + m/z 137.131 + m/z 95.086, 34%, 102 ?g C m-2 h-1) and methanol (m/z 33.032, 18%, 72 ?g C m-2 h-1). The next largest fluxes were detected at the following masses (attribution in parenthesis): m/z 59.048 (mostly acetone, 12.2%, 36.5 ?g C m-2 h-1), m/z 61.027 (mostly acetic acid, 11.9%, 35.7 ?g C m-2 h-1), m/z 93.069 (para-cymene + toluene, 4.1%, 12.2 ?g C m-2 h-1), m/z 45.033 (acetaldehyde, 3.8%, 11.5 ?g C m-2 h-1), m/z 71.048 (methylvinylketone + methacrolein, 2.4%, 7.1 ?g C m-2 h-1), and m/z 69.071 (isoprene + 2-methyl-3-butene-2-ol, 1.8%, 5.3 ?g C m-2 h-1). Low levels of emission and/or deposition (<1.6% for each, 5.8% in total flux) were observed for the additional reported masses. Overall, our results show that EC flux measurements using PTR-TOF-MS is a powerful new tool for characterizing the biosphere-atmosphere exchange including both emission and deposition for a large range of BVOC and their oxidation products.

Park, J.-H.; Goldstein, A. H.; Timkovsky, J.; Fares, S.; Weber, R.; Karlik, J.; Holzinger, R.

2012-08-01

29

Eddy covariance emission and deposition flux measurements using proton transfer reaction - time of flight - mass spectrometry (PTR-TOF-MS): comparison with PTR-MS measured vertical gradients and fluxes  

NASA Astrophysics Data System (ADS)

During summer 2010, a proton transfer reaction - time of flight - mass spectrometer (PTR-TOF-MS) and a quadrupole proton transfer reaction mass spectrometer (PTR-MS) were deployed simultaneously for one month in an orange orchard in the Central Valley of California to collect continuous data suitable for eddy covariance (EC) flux calculations. The high time resolution (5 Hz) and high mass resolution (up to 5000 m/?m) data from the PTR-TOF-MS provided the basis for calculating the concentration and flux for a wide range of volatile organic compounds (VOC). Throughout the campaign, 664 mass peaks were detected in mass-to-charge ratios between 10 and 1278. Here we present PTR-TOF-MS EC fluxes of the 27 ion species for which the vertical gradient was simultaneously measured by PTR-MS. These EC flux data were validated through spectral analysis (i.e., co-spectrum, normalized co-spectrum, and ogive). Based on inter-comparison of the two PTR instruments, no significant instrumental biases were found in either mixing ratios or fluxes, and the data showed agreement within 5% on average for methanol and acetone. For the measured biogenic volatile organic compounds (BVOC), the EC fluxes from PTR-TOF-MS were in agreement with the qualitatively inferred flux directions from vertical gradient measurements by PTR-MS. For the 27 selected ion species reported here, the PTR-TOF-MS measured total (24 h) mean net flux of 299 ?g C m-2 h-1. The dominant BVOC emissions from this site were monoterpenes (m/z 81.070 + m/z 137.131 + m/z 95.086, 34%, 102 ?g C m-2 h-1) and methanol (m/z 33.032, 18%, 72 ?g C m-2 h-1). The next largest fluxes were detected at the following masses (attribution in parenthesis): m/z 59.048 (mostly acetone, 12.2%, 36.5 ?g C m-2 h-1), m/z 61.027 (mostly acetic acid, 11.9%, 35.7 ?g C m-2 h-1), m/z 93.069 (para-cymene + toluene, 4.1%, 12.2 ?g C m-2 h-1), m/z 45.033 (acetaldehyde, 3.8%, 11.5 ?g C m-2 h-1), m/z 71.048 (methylvinylketone + methacrolein, 2.4%, 7.1 ?g C m-2 h-1), and m/z 69.071 (isoprene + 2-methyl-3-butene-2-ol, 1.8%, 5.3 ?g C m-2 h-1). Low levels of emission and/or deposition (<1.6% for each, 5.8% in total flux) were observed for the additional reported masses. Overall, our results show that EC flux measurements using PTR-TOF-MS is a powerful new tool for characterizing the biosphere-atmosphere exchange including both emission and deposition for a large range of BVOC and their oxidation products.

Park, J.-H.; Goldstein, A. H.; Timkovsky, J.; Fares, S.; Weber, R.; Karlik, J.; Holzinger, R.

2013-02-01

30

Rapid identification of Legionella spp. by MALDI-TOF MS based protein mass fingerprinting.  

PubMed

A set of reference strains representing 38 different Legionella species were submitted to Whole Cell Mass Spectrometry (WCMS) with MALDI-TOF. The dendrogram computed from strain mass spectral patterns obtained by WCMS was compared to the phylogenetic tree obtained from macrophage infectivity potentiator (mip) sequences. The trees inferred from these two methods revealed significant homologies. Using 453 Legionella isolates previously characterized by genotyping, it was possible to create species-specific SuperSpectra, using appropriate sets of spectral masses, allowing unambiguous differentiation and identification of the most frequently isolated Legionella species. These SuperSpectra were tested for their suitability to identify Legionella strains isolated from water samples, cooling towers, potting soils and patient specimens deposited at the Swiss National Reference Centre for Legionella and previously identified by molecular methods such as mip gene sequencing. 99.1% of the tested strains isolated from the environment could be correctly identified by comparison with the new SuperSpectra. The identification of Legionella spp. by MALDI-TOF MS is rapid, easy to perform and has the advantage of being time- and cost-saving, in comparison to sequence-based identification. PMID:21247716

Gaia, Valeria; Casati, Simona; Tonolla, Mauro

2011-02-01

31

Volatile Organic Compound emissions from soil: using Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-TOF-MS) for the real time observation of microbial processes  

NASA Astrophysics Data System (ADS)

In this study we report on the emissions of volatile organic compounds (VOC) and nitric oxide (NO) from two contrasting soils (equatorial rainforest and arid cotton field) analyzed in a laboratory based dynamic chamber system. The effect of soil moisture and soil temperature on VOC and NO emission was examined in laboratory incubation experiments by measuring as a pre-saturated soil dried out. Our results suggest that real time monitoring of VOC emissions from soil using a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) instrument can be used to improve our understanding of the release mechanisms of trace gases (e.g. NO, N2O) that are involved in the nitrogen cycle. Moreover, we report on the release rate of various VOC species, many of which exhibit a temperature dependent response indicative of biological production, namely a temperature amplification factor (Q10) ∼ 2-3. Contrary to the conventional modeling of NO emissions from soils, that the release of NO from the overall community across the range of soil water content can be modeled as an optimum function, we suggest that VOC measurements indicate there exist multiple distinct contributing microbial guilds releasing NO. These microbial guilds could likely be individually identified with the observed VOC profiles. Using a cotton field soil sample from a Sache oasis (Taklimakan desert, Xinijang, P. R. China), we identify five VOC emission groups with varying degrees of NO co-emission. An equatorial rainforest soil (Suriname) was shown to emit a variety of VOC including acetaldehyde, acetone, DMS, formaldehyde, and isoprene that vary strongly and individually as a function of temperature and soil moisture content. PTR-TOF-MS with high time resolution, sensitivity, and molecular specificity is an ideal tool for the real time analysis of VOC and NO emitting processes in soil systems. These experiments can be used as a template for future experiments to more completely and specifically identify the active microbial guilds in soils and to characterize the impact of soil VOC emissions on the atmosphere.

Veres, P. R.; Behrendt, T.; Klapthor, A.; Meixner, F. X.; Williams, J.

2014-08-01

32

A simple protocol for Matrix Assisted Laser Desorption Ionization- time of flight-mass spectrometry (MALDI-TOF-MS) analysis of lipids and proteins in single microsamples of paintings.  

PubMed

A simple protocol, based on Bligh-Dyer (BD) extraction followed by MALDI-TOF-MS analysis, for fast identification of paint binders in single microsamples is proposed. For the first time it is demonstrated that the BD method is effective for the simultaneous extraction of lipids and proteins from complex, and atypical matrices, such as pigmented paint layers. The protocol makes use of an alternative denaturing anionic detergent (RapiGest™) in order to improve efficiency of protein digestion and purification step. Detection of various lipid classes, such as triacylglycerols (TAGs) and phospholipids (PLs), and their oxidation by-products was accomplished, whereas proteins could be identified by peptide mass fingerprinting. The effect of pigments on ageing of lipids and proteins was also investigated. Finally, the proposed protocol was successfully applied to the study of a late-15th century Italian panel painting allowing the identification of various proteinaceous and lipid sections in organic binders, such as egg yolk, egg white, animal glue, casein, and drying oil. PMID:22305892

van der Werf, Inez D; Calvano, Cosima D; Palmisano, Francesco; Sabbatini, Luigia

2012-03-01

33

Matrix-assisted laser desorption\\/ionization mass spectrometry (MALDI TOF MS) study of Huperzine A, a natural anti-Alzheimer's disease product, its derivatization and its detection by highly sensitive laser induced fluorescence (LIF)  

Microsoft Academic Search

Huperzine A, a reversible acetylcholinesterase inhibitor for the treatment of Alzheimer disease (HupA), was studied using an (MALDI TOF MS) instrument in MALDI mode. The formation of a HupA dimmer in a vacuum was observed and several matrices were found that were able to inhibit its formation. The structures of the neutral and protonated form of the HupA molecule were

A. Ben Hameda; P. Táborský; E. M. Peña-Méndez; J. Havel

2007-01-01

34

Analysis of Wheat Prolamins, the Causative Agents of Celiac Sprue, Using Reversed Phase High Performance Liquid Chromatography (RP-HPLC) and Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS)  

PubMed Central

Wheat prolamins, commonly known as “gluten”, are a complex mixture of 71–78 proteins, which constitute ~80% of the proteins in the wheat grains and supply 50% of the global dietary protein demand. Prolamins are also responsible for numerous gluten-induced disorders and determine the unique visco-elastic properties of the wheat dough. These properties necessitate the reliable determination of the prolamin composition in wheat grains and their derived products. Therefore, this study examined the impact of HPLC conditions, including column type, column temperature, flow rate, and the gradient of polar and non-polar solvents in the mobile phase, to improve the analytical resolution of prolamins. The following conditions were found optimal for analyses: column temperature 60 °C, flow rate 1.0 mL/min and an elution gradient of 20%–60% of 0.1% trifluoroacetic acid + acetonitrile in 60 min. For further improvement of resolution, gliadin and glutenin extracts were analyzed using MALDI-TOF-MS in combination with HPLC fractionation. Two semi-quantitative methods, densitometry of stained polyacrylamide gels and HPLC, were used to determine relative prolamin quantities and the correspondence between the methods was established. The combinatorial gluten analyses approach developed during the present study was used to analyze prolamin profiles of wheat transformants expressing DEMETER silencing artificial microRNA, and the results are discussed. PMID:24739977

Mejías, Jaime H.; Lu, Xiaoqiao; Osorio, Claudia; Ullman, Jeffrey L.; von Wettstein, Diter; Rustgi, Sachin

2014-01-01

35

Metabolomic Analysis Using Ultra-Performance Liquid Chromatography-Quadrupole-Time of Flight Mass Spectrometry (UPLC-Q-TOF MS) Uncovers the Effects of Light Intensity and Temperature under Shading Treatments on the Metabolites in Tea  

PubMed Central

To investigate the effect of light intensity and temperature on the biosynthesis and accumulation of quality-related metabolites, field grown tea plants were shaded by Black Net and Nano-insulating Film (with additional 2–4°C cooling effect) with un-shaded plants as a control. Young shoots were subjected to UPLC-Q-TOF MS followed by multivariate statistical analysis. Most flavonoid metabolites (mainly flavan-3-ols, flavonols and their glycosides) decreased significantly in the shading treatments, while the contents of chlorophyll, ?-carotene, neoxanthin and free amino acids, caffeine, benzoic acid derivatives and phenylpropanoids increased. Comparison between two shading treatments indicated that the lower temperature under Nano shading decreased flavonols and their glycosides but increased accumulation of flavan-3-ols and proanthocyanidins. The comparison also showed a greater effect of temperature on galloylation of catechins than light intensity. Taken together, there might be competition for substrates between the up- and down-stream branches of the phenylpropanoid/flavonoid pathway, which was influenced by light intensity and temperature. PMID:25390340

Ma, Lifeng; Yi, Xiaoyun; Ruan, Jianyun

2014-01-01

36

Effect of metformin on the urinary metabolites of diet-induced-obese mice studied by ultra performance liquid chromatography coupled to time-of-flight mass spectrometry (UPLC-TOF/MS).  

PubMed

Obesity is becoming a health concern worldwide and metformin, a first line anti-diabetic drug, was associated with weight loss under different backgrounds. However, most researches focused on the anti-diabetic mechanism and less attention has been paid on the mechanism of weight loss of metformin. Therefore, we established a metabonomic method to evaluate metformin action in preventing obesity in a high fat diet-induced-obesity (DIO) mice model. 36 male C57BL/6 mice (8-week old) were randomly divided into control group (n=12, normal chow), model group (n=12, high fat chow) and metformin group (n=12, high fat chow and dosed with metformin) over 16 weeks. A urinary metabonomic study using UPLC-TOF/MS was performed in combination with multivariate statistical analysis. In addition, indices of body weight and food intake as well as fasting blood glucose, fed blood glucose, oral glucose tolerance test (OGTT) and plasma insulin were collected. Significant weight loss in metformin-treated mice was achieved and 21 potential biomarkers were identified. Decreased glucose, myristic acid, stearidonic acid, lysoPC (16:0), lysoPC (18:0), L-glutamic acid, L-methionine, L-threonine, L-phenylalanine, L-histidine, L-carnitine, L-malic acid and pantothenic acid in urine indicated that metformin may have exerted effects on energy metabolism. Further, based on the biomarkers, we cautiously propose that tricarboxylic acid cycle (TCA) may have been compromised by metformin and might contribute to the activation of adenosine monophosphate kinase (AMPK), then AMPK activation led to more ?-oxidation of certain fatty acids and augmented lipolysis and thus induced weight loss. Related cellular and molecular studies are being considered to further investigate the underlying mechanism. PMID:23523884

Zhu, Yunyun; Feng, Yi; Shen, Lan; Xu, Desheng; Wang, Bin; Ruan, Kefeng; Cong, Wenjuan

2013-04-15

37

Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) of Rhenium(III) Halides: A Characterization Tool for Metal Atom Clusters.  

PubMed

The laser desorption/ionization (LDI) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra of trinuclear Cs(3)Re(3)Cl(12) and Cs(3)Re(3)Br(12) and dinuclear (Bu(4)N)(2)[Re(2)Cl(8)] are reported. In each case, characteristic fragments due to the loss of halogen atoms give ion signals that can be used to identify the number of rhenium atoms and the identity of ligands bound to the cluster. The ion signals are identified by both m/z values and distinctive isotope patterns. The results presented here illustrate the usefulness of MALDI-TOF mass spectrometry in the characterization of metal atom clusters. PMID:11670333

Dopke, Nancy Carter; Treichel, Paul M.; Vestling, Martha M.

1998-03-23

38

Profile of phenolic compounds of Brazilian virgin olive oils by rapid resolution liquid chromatography coupled to electrospray ionisation time-of-flight mass spectrometry (RRLC-ESI-TOF-MS).  

PubMed

In recent years, agronomical researchers began to cultivate several olive varieties in different regions of Brazil to produce virgin olive oil (VOO). Because there has been no reported data regarding the phenolic profile of the first Brazilian VOO, the aim of this work was to determine phenolic contents of these samples using rapid-resolution liquid chromatography coupled to electrospray ionisation time-of-flight mass spectrometry. 25 VOO samples from Arbequina, Koroneiki, Arbosana, Grappolo, Manzanilla, Coratina, Frantoio and MGS Mariense varieties from three different Brazilian states and two crops were analysed. It was possible to quantify 19 phenolic compounds belonging to different classes. The results indicated that Brazilian VOOs have high total phenolic content because the values were comparable with those from high-quality VOOs produced in other countries. VOOs from Coratina, Arbosana and Grappolo presented the highest total phenolic content. These data will be useful in the development and improvement of Brazilian VOO. PMID:25306359

Ballus, Cristiano Augusto; Quirantes-Piné, Rosa; Bakhouche, Abdelhakim; da Silva, Luiz Fernando de Oliveira; de Oliveira, Adelson Francisco; Coutinho, Enilton Fick; da Croce, Dorli Mario; Segura-Carretero, Antonio; Godoy, Helena Teixeira

2015-03-01

39

The influence of matrix and laser energy on the molecular mass distribution of synthetic polymers obtained by MALDI-TOF-MS  

NASA Astrophysics Data System (ADS)

The molecular mass distribution (MMD) obtained in synthetic polymer characterization by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) may be biased by preferential desorption/ionization of low mass polymer molecules, preferential ion attachment to larger polymers, or degradation and fragmentation due to the desorption process. In this study we focus on the effect of matrix and laser energy on the MMD of four synthetic polymers of low polydispersity with varying thermal stabilities. The four polymers considered were polystyrene (PS), poly(ethylene glycol) (PEG), poly(methyl methacrylate) (PMMA) and poly(tetrahydrofuran) (PTHF). The matrix in which the polymer is analyzed may also influence the laser energy effect of MALDI and was also considered in this paper. Three common matrixes were considered, dithranol, all trans-retinoic acid (RA) and 2,5-dihydroxybenzoic acid (DHB). Statistical analyses of the molecular mass distributions, obtained by varying laser energy and matrixes, reveal trends that can be used to describe the influences of matrix and laser energy on MALDI-TOF-MS data measurement of synthetic polymers. The statistical analysis revealed that the matrix has a greater effect on the polymer MMD than was expected. Polymers analyzed in DHB yielded lower mass moments than polymers analyzed in RA and dithranol. The effects of laser power on the MMD of the polymers were found to be matrix dependent.

Wetzel, Stephanie J.; Guttman, Charles M.; Girard, James E.

2004-11-01

40

Construction and application of a mass spectral and retention time index database generated from plant GC\\/EI-TOF-MS metabolite profiles  

Microsoft Academic Search

The non-supervised construction of a mass spectral and retention time index data base (MS\\/RI library) from a set of plant metabolic profiles covering major organs of potato (Solanum tuberosum), tobacco (Nicotiana tabaccum), and Arabidopsis thaliana, was demonstrated. Typically 300–500 mass spectral components with a signal to noise ratio ?75 were obtained from GC\\/EI-time-of-flight (TOF)-MS metabolite profiles of methoxyaminated and trimethylsilylated

Cornelia Wagner; Michael Sefkow; Joachim Kopka

2003-01-01

41

Identification of Dermatophyte Species after Implementation of the In-House MALDI-TOF MS Database  

PubMed Central

Despite that matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) has become a powerful tool in the clinical microbiology setting, few studies have till now focused on MALDI-TOF MS-based identification of dermatophytes. In this study, we analyze dermatophytes strains isolated from clinical samples by MALDI-TOF MS to supplement the reference database available in our laboratory. Twenty four dermatophytes (13 reference strains and 11 field isolated strains), identified by both conventional and molecular standard procedures, were analyzed by MALDI-TOF MS, and the spectra obtained were used to supplement the available database, limited to a few species. To verify the robustness of the implemented database, 64 clinical isolates other than those used for the implementation were identified by MALDI-TOF MS. The implementation allowed the identification of the species not included in the original database, reinforced the identification of the species already present and correctly identified those within the Trichophyton mentagrophytes complex previously classified as Trichophyton. tonsurans by MALDI-TOF MS. The dendrogram obtained by analyzing the proteic profiles of the different species of dermatophytes reflected their taxonomy, showing moreover, in some cases, a different clusterization between the spectra already present in the database and those newly added. In this study, MALDI-TOF MS proved to be a useful tool suitable for the identification of dermatophytes for diagnostic purpose. PMID:25216335

Calderaro, Adriana; Motta, Federica; Montecchini, Sara; Gorrini, Chiara; Piccolo, Giovanna; Piergianni, Maddalena; Buttrini, Mirko; Medici, Maria Cristina; Arcangeletti, Maria Cristina; Chezzi, Carlo; De Conto, Flora

2014-01-01

42

Identification of Dermatophyte species after implementation of the in-house MALDI-TOF MS database.  

PubMed

Despite that matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) has become a powerful tool in the clinical microbiology setting, few studies have till now focused on MALDI-TOF MS-based identification of dermatophytes. In this study, we analyze dermatophytes strains isolated from clinical samples by MALDI-TOF MS to supplement the reference database available in our laboratory. Twenty four dermatophytes (13 reference strains and 11 field isolated strains), identified by both conventional and molecular standard procedures, were analyzed by MALDI-TOF MS, and the spectra obtained were used to supplement the available database, limited to a few species. To verify the robustness of the implemented database, 64 clinical isolates other than those used for the implementation were identified by MALDI-TOF MS. The implementation allowed the identification of the species not included in the original database, reinforced the identification of the species already present and correctly identified those within the Trichophyton mentagrophytes complex previously classified as Trichophyton. tonsurans by MALDI-TOF MS. The dendrogram obtained by analyzing the proteic profiles of the different species of dermatophytes reflected their taxonomy, showing moreover, in some cases, a different clusterization between the spectra already present in the database and those newly added. In this study, MALDI-TOF MS proved to be a useful tool suitable for the identification of dermatophytes for diagnostic purpose. PMID:25216335

Calderaro, Adriana; Motta, Federica; Montecchini, Sara; Gorrini, Chiara; Piccolo, Giovanna; Piergianni, Maddalena; Buttrini, Mirko; Medici, Maria Cristina; Arcangeletti, Maria Cristina; Chezzi, Carlo; De Conto, Flora

2014-01-01

43

Single peptide-based protein identification in human proteome through MALDI-TOF MS coupled with amino acids coded mass tagging.  

PubMed

Identification of proteins with low sequence coverage using mass spectrometry (MS) requires tandem MS/MS peptide sequencing. It is very challenging to obtain a complete or to interpret an incomplete tandem MS/MS spectrum from fragmentation of a weak peptide ion signal for sequence assignment. Here, we have developed an effective and high-throughput MALDI-TOF-based method for the identification of membrane and other low-abundance proteins with a simple, one-dimensional separation step. In this approach, several stable isotope-labeled amino acid precursors were selected to mass-tag, in parallel, the human proteome of human skin fibroblast cells in a residue-specific manner during in vivo cell culturing. These labeled residues can be recognized by their characteristic isotope patterns in MALDI-TOF MS spectra. The isotope pattern of particular peptides induced by the different labeled precursors provides information about their amino acid compositions. The specificity of peptide signals in a peptide mass mapping is thus greatly enhanced, resolving a high degree of mass degeneracy of proteolytic peptides derived from the complex human proteome. Further, false positive matches in database searching can be eliminated. More importantly, proteins can be accurately identified through a single peptide with its m/z value and partial amino acid composition. With the increased solubility of hydrophobic proteins in SDS, we have demonstrated that our approach is effective for the identification of membrane and low-abundant proteins with low sequence coverage and weak signal intensity, which are often difficult for obtaining informative fragment patterns in tandem MS/MS peptide sequencing analysis. PMID:12659191

Pan, Songqin; Gu, Sheng; Bradbury, E Morton; Chen, Xian

2003-03-15

44

Identification of metabolites of deoxyschizandrin in rats by UPLC-Q-TOF-MS/MS based on multiple mass defect filter data acquisition and multiple data processing techniques.  

PubMed

Deoxyschizandrin is an active lignin ingredient originating from Schisandra chinensis (Turcz.) Baill or Schisandrae Sphenantherae Fructus. In the present study, a novel and efficient strategy was developed for the in vivo screening and identification of deoxyschizandrin metabolites using ultra high performance liquid chromatography combined with triple TOF mass spectrometry (UPLC-TOF/MS/MS). This strategy was characterized by the following: a novel and unique multiple mass defect filter (MMDF) combined with an on-line data acquisition method that is dependent on dynamic background subtraction (DBS) was developed to trace all of the probable metabolites of deoxyschizandrin. The MMDF and DBS methods could trigger an IDA scan for the low-level metabolites that are masked by background noise and endogenous components. A combination of data processing methods including extracted ion chromatography (XIC), mass defect filtering (MDF), product ion filtering (PIF) and neutral loss filtering (NLF) were employed to identify the metabolites of deoxyschizandrin. Next, the structures of the metabolites were elucidated based on an accurate mass measurement, the fragmentation patterns of the parent drug and relevant drug bio-transformation knowledge. Finally, an important parameter ClogP was used to estimate the retention time of isomers. Based on the proposed strategy, 51 metabolites (including 49 phase I and 2 phase II metabolites) were identified in rats after the oral administration of deoxyschizandrin. Among these metabolites, 41 metabolites were characterized in the rat urine, and 28 metabolites were identified in the rat bile. The results indicated that oxidization was the main metabolic pathway and that the methoxy group and the biphenyl cyclooctene were the metabolic sites. Conjugation with sulfate and cysteine groups produced two phase-II metabolites. This study firstly reported the description of deoxyschizandrin metabolism in vivo. This study provided a practical strategy for rapidly screening and identifying metabolites, and this methodology can be widely applied for the structural characterization of the metabolites of other compounds. PMID:24487041

Liu, Minyan; Zhao, Shaohua; Wang, Zongquan; Wang, Yufeng; Liu, Ting; Li, Song; Wang, Cuicui; Wang, Hongtao; Tu, Pengfei

2014-02-15

45

Performance of mass spectrometric identification of bacteria and yeasts routinely isolated in a clinical microbiology laboratory using MALDI-TOF MS  

PubMed Central

Background Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is an emerging technology newly applied to identifying bacterial and yeast strains. The aim of this study was to evaluate the clinical performance of the VITEK® MS system in the identification of bacteria and yeast strains routinely isolated from clinical samples. Methods We prospectively analyzed routine MALDI-TOF mass spectrometry identification in parallel with conventional phenotypic identification of bacteria and yeasts regardless of phylum or source of isolation. Discordant results were resolved with 16S rDNA or internal transcribed spacer (ITS) gene sequencing. Colonies (a single deposit on a MALDI disposable target without any prior extraction step) were analyzed using the VITEK® MS system. Peptide spectra acquired by the system were compared with the VITEK® MS IVD database Version 2.0, and the identification scores were recorded. Results Of the 1,181 isolates (1,061 bacterial isolates and 120 yeast isolates) analyzed, 99.5% were correctly identified by MALDI-TOF mass spectrometry; 95.7% identified to the species level, 3.6% identified to the genus level, and 0.3% identified within a range of species belonging to different genera. Conversely, 0.1% of isolates were misidentified and 0.4% were unidentified, partly because the species were not included in the database. Re-testing using a second deposit provided a successful identification for 0.5% of isolates unidentified with the first deposit. Our results show that the VITEK® MS system has exceptional performance in identifying bacteria and yeast by comparing acquired peptide spectra to those contained in its database. Conclusions MALDI-TOF mass spectrometry is a rapid, accurate, and relatively inexpensive method for bacterial and yeast identification. Our results demonstrate that the VITEK® MS system is a fast and reliable technique, and has the potential to replace conventional phenotypic identification for most bacterial and yeast strains routinely isolated in clinical microbiology laboratories. PMID:24822114

Wang, Weiping; Xi, Haiyan; Huang, Mei; Wang, Jie; Fan, Ming; Chen, Yong; Shao, Haifeng

2014-01-01

46

Wine yeast typing by MALDI-TOF MS.  

PubMed

For the production of wine, the most important industrially used yeast species is Saccharomyces cerevisiae. Years of experience have shown that wine quality and property are significantly affected by the employed strain conducting the fermentation. Consequently, the ability of a strain level differentiation became an important requirement of modern winemaking. In our study, we showed that the differentiation by time-consuming and laborious biochemical and DNA-based methods to enable a constant beverage quality and characteristics can be replaced by matrix-assisted-laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), accompanied by the additional benefit of an application prediction. Mass fingerprints of 33 Saccharomyces strains, which are commonly used for varying wine fermentations, were generated by MALDI-TOF MS upon optimized sample preparation and instrument settings and analyzed by a cluster analysis for strain or ecotype-level differentiation. As a reference method, delta-PCR was chosen to study the genetic diversity of the employed strains. Finally, the cluster analyses of both methods were compared. It could be shown that MALDI-TOF MS, acting at proteome level, provides valuable information about the relationship between yeast strains and their application potential according to their MALDI mass fingerprint. PMID:24615383

Usbeck, Julia C; Wilde, Caroline; Bertrand, Dave; Behr, Jürgen; Vogel, Rudi F

2014-04-01

47

Analysis of Black Mulberry Volatiles Using GCxGC-TOF\\/MS  

Microsoft Academic Search

Volatile constituents of black mulberry (Morus nigra) dried with various commercially used techniques (sun, hot air, and microwaves) were obtained by direct thermal desorption and analysed using comprehensive GCxGC coupled with time of flight mass spectrometry (TOF\\/MS). Some mulberries were dried using only a desiccator and the volatile desorbed from these was used for comparison. The number of components of

F. Gö?ü?; A. C. Lewis; M. Z. Özel

2011-01-01

48

MALDI-TOF MS sample preparation by using alkanethiolate self-assembled monolayers  

NASA Astrophysics Data System (ADS)

Samples originating from body fluids often contain a complex mixture of inorganic salts, buffers, chaotropic agents, surfactant/detergents, preservatives, and other solubilizing agents. The presence of those contaminants often precludes direct analysis by matrix-assisted laser-desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Self-assembled monolayers (SAMs) on coinage metal can provide versatile modeling systems for studies of interfacial electron transfer, biological interactions, molecular recognition and other interfacial phenomena. In this study, SAMs surface was used for MALDI-TOF MS sample cleanup application. Experimental results from MALDI-TOF MS have revealed the better S/N ratio and resolution of using functionalized SAMs surface for the demonstration of bovine serum albumin (BSA) in artificial human urine sample. This paper reports a surface modification and cleanup method that greatly simplifies this sample preparation process.

Tyan, Yu-Chang; Yang, Ming-Hui; Liao, Pao-Chi; Liao, Jiunn-Der; Jong, Shiang-Bin; Liu, Chia-Yuan; Wang, Ming-Chen; Grunze, Michael

2007-04-01

49

Application of MALDI-TOF MS for the Identification of Food Borne Bacteria  

PubMed Central

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently emerged as a powerful tool for the routine identification of clinical isolates. MALDI-TOF MS based identification of bacteria has been shown to be more rapid, accurate and cost-efficient than conventional phenotypic techniques or molecular methods. Rapid and reliable identification of food-associated bacteria is also of crucial importance for food processing and product quality. This review is concerned with the applicability of MALDI-TOF MS for routine identification of foodborne bacteria taking the specific requirements of food microbiological laboratories and the food industry into account. The current state of knowledge including recent findings and new approaches are discussed. PMID:24358065

Pavlovic, Melanie; Huber, Ingrid; Konrad, Regina; Busch, Ulrich

2013-01-01

50

Comparison of MALDI-TOF MS, gene sequencing and the Vitek 2 for identification of seventy-three clinical isolates of enteropathogens  

PubMed Central

Objective This study was performed to evaluate the analytical and practical performance of the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) compared to the sequencing method and the Vitek 2 system for identi?cation of enteropathogens in the clinical microbiology laboratory. Methods Ten type strains and 73 clinical isolates of enteropathogens representing eight genera were analyzed by MALDI-TOF MS. All isolates were also characterized by gene sequencing allowing interpretation of the results from MALDI-TOF MS. In addition, MALDI-TOF MS was compared with the Vitek 2 system for the identi?cation of ten isolates of Aeromonas and six of Salmonella. Results As previously known, identification between Shigella and Escherichia coli is not possible to distinguish. MALDI-TOF MS produced the correct identifications for all other type strains and clinical isolates to the genus level. Fifteen Campylobacter jejuni, six Campylobacter coli, three Plesiomonas shigelloides, three Yersinia enterocolitica, two Clostridium difficile, one Vibrio parahaemolyticus, one Vibrio fluvialis, and one Vibrio cholera were all correctly identi?ed to the species level. Genus and species identifications of ten Aeromonas and six Salmonella isolates by MALDI-TOF MS were consistent with those by the Vitek 2, but with much less cost and about ten times faster. Conclusions This study demonstrates that MALDI-TOF MS is a powerful tool for fast, accurate and low-cost identi?cation of enteropathogens in the clinical microbiology laboratory. PMID:24822116

Deng, Jiankai; Fu, Liang; Wang, Ruilian; Ding, Xixia; Jiang, Lingxiao; Fang, Yanping; Jiang, Changhong; Lin, Lijuan; Che, Xiaoyan

2014-01-01

51

Biochemical Assays of Immobilized Oligonucleotides with Mass Spectrometry  

E-print Network

Biochemical Assays of Immobilized Oligonucleotides with Mass Spectrometry Haim Tsubery and Milan the use of mass spectrometry to characterize oligonucleotides immobilized to the surfaces of biochips- assisted laser desorption/iozation and time-of-flight mass spectrometry (MALDI-TOF MS). Examples are shown

Mrksich, Milan

52

A critical assessment of SELDI-TOF-MS for biomarker discovery in serum and tissue of patients with an ovarian mass  

PubMed Central

Background Less than 25% of patients with a pelvic mass who are presented to a gynecologist will eventually be diagnosed with epithelial ovarian cancer. Since there is no reliable test to differentiate between different ovarian tumors, accurate classification could facilitate adequate referral to a gynecological oncologist, improving survival. The goal of our study was to assess the potential value of a SELDI-TOF-MS based classifier for discriminating between patients with a pelvic mass. Methods Our study design included a well-defined patient population, stringent protocols and an independent validation cohort. We compared serum samples of 53 ovarian cancer patients, 18 patients with tumors of low malignant potential, and 57 patients with a benign ovarian tumor on different ProteinChip arrays. In addition, from a subset of 84 patients, tumor tissues were collected and microdissection was used to isolate a pure and homogenous cell population. Results Diagonal Linear Discriminant Analysis (DLDA) and Support Vector Machine (SVM) classification on serum samples comparing cancer versus benign tumors, yielded models with a classification accuracy of 71-81% (cross-validation), and 73-81% on the independent validation set. Cancer and benign tissues could be classified with 95-99% accuracy using cross-validation. Tumors of low malignant potential showed protein expression patterns different from both benign and cancer tissues. Remarkably, none of the peaks differentially expressed in serum samples were found to be differentially expressed in the tissue lysates of those same groups. Conclusion Although SELDI-TOF-MS can produce reliable classification results in serum samples of ovarian cancer patients, it will not be applicable in routine patient care. On the other hand, protein profiling of microdissected tumor tissue may lead to a better understanding of oncogenesis and could still be a source of new serum biomarkers leading to novel methods for differentiating between different histological subtypes. PMID:22824475

2012-01-01

53

[Identification of staphylococci directly from positive blood culture bottles by MALDI-TOF MS system].  

PubMed

Bloodstream infections are substantial causes of morbidity and mortality worldwide. Staphylococcus species are the most commonly isolated microorganisms from blood cultures in clinical microbiology laboratories. MALDI-TOF MS (Matrix-Assisted Laser Desorption/Ionization Time- of- Flight Mass Spectrometry) system allows the identification of microorganisms directly from positive blood culture bottles. The aim of this study was to evaluate the MALDI-TOF MS system for the identification of staphylococci directly from the positive blood culture bottles which revealed the presence of gram-positive cocci by staining. A total of 96 positive blood culture bottles that yielded gram-positive cocci by Gram stain were evaluated. These blood cultures were obtained from 69 patients between December 2013-February 2014. Conventional methods and BD Phoenix™ automated bacterial identification system (Becton Dickinson, USA) were used for routine identification. The strains were also identified by real-time Taqman PCR (qPCR) which was considered as the reference method. In MALDI-TOF MS method, MALDI Sepsityper™ Kit was used for the bacterial identification and all measurements were carried out by using Microflex LT instrument and FlexControl 3.0 software (Bruker Daltonics, USA). Of 96 culture bottles positive for gram-positive cocci, 90 were correctly identified as staphylococci at genus level with all the three study methods (qPCR, BD Phoenix, Bruker MALDI-TOF MS). The other six samples were identified as Enterococcus faecium (n= 4) and Streptococcus pyogenes (n= 2) by both Phoenix and the MALDI-TOF systems. Of the 90 samples, 87 were identified at the species level (15 S.aureus, 33 S.epidermidis, 29 S.hominis, 10 S.haemolyticus) and three at the genus level by the reference qPCR method. When comparing the results obtained by qPCR and Bruker MALDI-TOF MS, incompatibility was detected for three isolates. Those isolates were identified as S.hominis by qPCR, however two of them were identified as S.haemolyticus and one as S.epidermidis by MALDI-TOF MS. Compared with real-time Taqman PCR it was detected that Bruker MALDI TOF MS was identified 100% of S.aureus to the genus and species level and 100% and 96.6% of coagulase-negative staphylococci (CNS) to the genus and species level, respectively. In conclusion, it was thought that Bruker MALDI TOF MS system may allow rapid and reliable identification of S.aureus and CNS directly from positive blood culture bottles compared with the routine methods used in the clinical microbiology laboratory. PMID:25052104

Kilic, Abdullah; Baysallar, Mehmet

2014-07-01

54

Detection of Rickettsia spp in Ticks by MALDI-TOF MS  

PubMed Central

Background Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) has been shown to be an effective tool for the rapid identification of arthropods, including tick vectors of human diseases. Methodology/Principal Findings The objective of the present study was to evaluate the use of MALDI-TOF MS to identify tick species, and to determine the presence of rickettsia pathogens in the infected Ticks. Rhipicephalus sanguineus and Dermacentor marginatus Ticks infected or not by R. conorii conorii or R. slovaca, respectively, were used as experimental models. The MS profiles generated from protein extracts prepared from tick legs exhibited mass peaks that distinguished the infected and uninfected Ticks, and successfully discriminated the Rickettsia spp. A blind test was performed using Ticks that were laboratory-reared, collected in the field or removed from patients and infected or not by Rickettsia spp. A query against our in-lab arthropod MS reference database revealed that the species and infection status of all Ticks were correctly identified at the species and infection status levels. Conclusions/Significance Taken together, the present work demonstrates the utility of MALDI-TOF MS for a dual identification of tick species and intracellular bacteria. Therefore, MALDI-TOF MS is a relevant tool for the accurate detection of Rickettsia spp in Ticks for both field monitoring and entomological diagnosis. The present work offers new perspectives for the monitoring of other vector borne diseases that present public health concerns. PMID:25659152

Yssouf, Amina; Almeras, Lionel; Terras, Jérôme; Socolovschi, Cristina; Raoult, Didier; Parola, Philippe

2015-01-01

55

Rothia aeria mitral valve endocarditis complicated by multiple mycotic aneurysms: laboratory identification expedited using MALDI-TOF MS.  

PubMed

Rothia aeria has only rarely been described as a human pathogen. We describe a case of Rothia aeria causing mitral valve endocarditis and multiple mycotic aneurysms, including cerebral mycotic aneurysms. In the case described, early identification of Rothia aeria was achieved using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). PMID:24078192

Crowe, A; Ding, N S; Yong, E; Sheorey, H; Waters, M J; Daffy, J

2014-04-01

56

Top-down proteomic identification of protein biomarkers of food-borne pathogens using MALDI-TOF-TOF-MS/MS  

Technology Transfer Automated Retrieval System (TEKTRAN)

This chapter describes a step-by-step protocol and discussion of top-down proteomic identification of protein biomarkers of food-borne pathogens using matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF-TOF-MS/MS) and web-based software developed in the Pro...

57

MALDI-TOF MS Distinctly Differentiates Nontypable Haemophilus influenzae from Haemophilus haemolyticus  

PubMed Central

Nontypable Haemophilus influenzae (NTHi) and Haemophilus haemolyticus exhibit different pathogenicities, but to date, there remains no definitive and reliable strategy for differentiating these strains. In this study, we evaluated matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) as a potential method for differentiating NTHi and H. haemolyticus. The phylogenetic analysis of concatenated 16S rRNA and recombinase A (recA) gene sequences, outer membrane protein P6 gene sequencing and single-gene PCR were used as reference methods. The original reference database (ORD, provided with the Biotyper software) and new reference database (NRD, extended with Chinese strains) were compared for the evaluation of MALDI-TOF MS. Through a search of the ORD, 76.9% of the NTHi (40/52) and none of the H. haemolyticus (0/20) strains were identified at the species level. However, all NTHi and H. haemolyticus strains used for identification were accurately recognized at the species level when searching the NRD. From the dendrogram clustering of the main spectra projections, the Chinese and foreign H. influenzae reference strains were categorized into two distinct groups, and H. influenzae and H. haemolyticus were also separated into two categories. Compared to the existing methods, MALDI-TOF MS has the advantage of integrating high throughput, accuracy and speed. In conclusion, MALDI-TOF MS is an excellent method for differentiating NTHi and H. haemolyticus. This method can be recommended for use in appropriately equipped laboratories. PMID:23457514

Zhang, Huifang; Zhang, Yongchan; Gao, Yuan; Xu, Li; Lv, Jing; Wang, Yingtong; Zhang, Jianzhong; Shao, Zhujun

2013-01-01

58

Glycoprotein analysis using enzymatic digestion and MALDI-TOF MS  

NASA Astrophysics Data System (ADS)

A sensitive and facile method is described to identify the glycosylation sites and site-specific heterogeneity in the carbohydrate portion of glycoproteins. In this procedure, the peptide backbone of the glycoprotein is cleaved enzymatically. The peptide/glycopeptide mixture is divided into three fractions. The first fraction is analyzed directly by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), while the other two aliquots are analyzed by MALDI-TOF MS after enzymatic release of the N-linked and N- and O-linked chains. Comparison of these mass spectra provides the molecular weight of each carbohydrate side chain and of the peptide to which it is attached. This information combined with the protein's amino acid sequence identifies the glycosylation sites and provides information concerning site-specific oligosaccharide heterogeneity. This approach is faster and simpler than procedures currently used for glycosylation site mapping and can be performed on as little as 10 picomoles of glycoprotein.

Kornfeld, Rich; Kenny, James W.; Weinberger, Scot R.; Yang, Yi; Orlando, Ron

1996-04-01

59

Rapid identification of oral Actinomyces species cultivated from subgingival biofilm by MALDI-TOF-MS  

PubMed Central

Background Actinomyces are a common part of the residential flora of the human intestinal tract, genitourinary system and skin. Isolation and identification of Actinomyces by conventional methods is often difficult and time consuming. In recent years, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has become a rapid and simple method to identify bacteria. Objective The present study evaluated a new in-house algorithm using MALDI-TOF-MS for rapid identification of different species of oral Actinomyces cultivated from subgingival biofilm. Design Eleven reference strains and 674 clinical strains were used in this study. All the strains were preliminarily identified using biochemical methods and then subjected to MALDI-TOF-MS analysis using both similarity-based analysis and classification methods (support vector machine [SVM]). The genotype of the reference strains and of 232 clinical strains was identified by sequence analysis of the 16S ribosomal RNA (rRNA). Results The sequence analysis of the 16S rRNA gene of all references strains confirmed their previous identification. The MALDI-TOF-MS spectra obtained from the reference strains and the other clinical strains undoubtedly identified as Actinomyces by 16S rRNA sequencing were used to create the mass spectra reference database. Already a visual inspection of the mass spectra of different species reveals both similarities and differences. However, the differences between them are not large enough to allow a reliable differentiation by similarity analysis. Therefore, classification methods were applied as an alternative approach for differentiation and identification of Actinomyces at the species level. A cross-validation of the reference database representing 14 Actinomyces species yielded correct results for all species which were represented by more than two strains in the database. Conclusions Our results suggest that a combination of MALDI-TOF-MS with powerful classification algorithms, such as SVMs, provide a useful tool for the differentiation and identification of oral Actinomyces. PMID:25597306

Stingu, Catalina S.; Borgmann, Toralf; Rodloff, Arne C.; Vielkind, Paul; Jentsch, Holger; Schellenberger, Wolfgang; Eschrich, Klaus

2015-01-01

60

MALDI-TOF MS-based identification of black yeasts of the genus Exophiala.  

PubMed

In this study, we investigated the applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of Exophiala species. The analysis included a total of 110 Exophiala isolates, including 15 CBS strains representing 4 species, Exophiala dermatitidis (61), E. phaeomuriformis (36), E. crusticola (9), and E. heteromorpha (4), that had been previously identified based on internal transcribed spacer (ITS) regions. We also compared the relative efficacies of Sabouraud glucose agar (SGA) and Columbia agar (CA) for use in MALDI-TOF MS. Remarkably, we obtained a log-score value ?2.0 by using either SGA or CA for all 15 CBS strains, indicating species-level identification. The remaining 95 Exophiala strains were identified to the genus or species levels, with identification rates of 96.8% and 90.5%, using SGA or CA, respectively. Most of the E. dermatitidis (100% and 92.9%), E. phaeomuriformis (80.6% and 83.9%), E. crusticola (50% and 100%), and E. heteromorpha (100% and 100%) isolates were correctly identified using SGA or CA, respectively. Furthermore, 58.9% and 26.3% of the strains had log-score values of ?2.0 by using SGA and CA, respectively. Our results indicate that MALDI-TOF MS is a rapid and reliable technique with high rates of correct taxonomic identification. PMID:25851261

Özhak-Baysan, Betil; Ö?ünç, Dilara; Dö?en, Aylin; Ilkit, Macit; de Hoog, G Sybren

2015-05-01

61

High throughput identification of components from traditional Chinese medicine herbs by utilizing graphene or graphene oxide as MALDI-TOF-MS matrix.  

PubMed

In this work, graphene or graphene oxide was utilized, for the first time, to identify small molecular components from traditional Chinese medicine (TCM) herbs, by acting as matrix of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Due to the large surface area of graphene or graphene oxide, the analytes were trapped tightly to the matrix, which avoids the contamination of the ion source and vacuum system. Besides, their excellent electronic, thermal and mechanical properties make them desired matrices for MALDI-TOF-MS. Stable analysis was achieved with no background inference even at the concentration of 100 nM. Moreover, the limit of detection (LOD) could be greatly lowered by utilizing graphene or graphene oxide as a pre-enrichment adsorbent. In summary, the promoted MALDI-TOF-MS methodology was demonstrated to be simple, sensitive, fast, cost effective and, most importantly, high throughput. PMID:21834019

Liu, Yang; Liu, Junyan; Yin, Peng; Gao, Mingxia; Deng, Chunhui; Zhang, Xiangmin

2011-08-01

62

Fusobacterium nucleatum Subspecies Identification by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry.  

PubMed

We explored the use of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for identification of Fusobacterium nucleatum subspecies. MALDI-TOF MS spectra of five F. nucleatum subspecies (animalis, fusiforme, nucleatum, polymorphum, and vincentii) were analyzed and divided into four distinct clusters, including subsp. animalis, nucleatum, polymorphum, and fusiforme/vincentii. MALDI-TOF MS with the modified SARAMIS database further correctly identified 28 of 34 F. nucleatum clinical isolates to the subspecies level. PMID:25653408

Nie, Shuping; Tian, Baoyu; Wang, Xiaowei; Pincus, David H; Welker, Martin; Gilhuley, Kathleen; Lu, Xuedong; Han, Yiping W; Tang, Yi-Wei

2015-04-01

63

Validation of LC–TOF-MS Screening for Drugs, Metabolites, and Collateral Compounds in Forensic Toxicology Specimens  

PubMed Central

Liquid chromatography time-of-flight mass spectrometry (LC–TOF-MS) analysis provides an expansive technique for identifying many known and unknown analytes. This study developed a screening method that utilizes automated solid-phase extraction to purify a wide array of analytes involving stimulants, benzodiazepines, opiates, muscle relaxants, hypnotics, antihistamines, antidepressants and newer synthetic “Spice/K2” cannabinoids and cathinone “bath salt” designer drugs. The extract was applied to LC–TOF-MS analysis, implementing a 13 min chromatography gradient with mobile phases of ammonium formate and methanol using positive mode electrospray. Several common drugs and metabolites can share the same mass and chemical formula among unrelated compounds, but they are structurally different. In this method, the LC–TOF-MS was able to resolve many isobaric compounds by accurate mass correlation within 15 ppm mass units and a narrow retention time interval of less than 10 s of separation. Drug recovery yields varied among spiked compounds, but resulted in overall robust area counts to deliver an average match score of 86 when compared to the retention time and mass of authentic standards. In summary, this method represents a rapid, enhanced screen for blood and urine specimens in postmortem, driving under the influence, and drug facilitated sexual assault forensic toxicology casework. PMID:23118149

Guale, Fessessework; Shahreza, Shahriar; Walterscheid, Jeffrey P.; Chen, Hsin-Hung; Arndt, Crystal; Kelly, Anna T.; Mozayani, Ashraf

2013-01-01

64

Validation of LC-TOF-MS screening for drugs, metabolites, and collateral compounds in forensic toxicology specimens.  

PubMed

Liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) analysis provides an expansive technique for identifying many known and unknown analytes. This study developed a screening method that utilizes automated solid-phase extraction to purify a wide array of analytes involving stimulants, benzodiazepines, opiates, muscle relaxants, hypnotics, antihistamines, antidepressants and newer synthetic "Spice/K2" cannabinoids and cathinone "bath salt" designer drugs. The extract was applied to LC-TOF-MS analysis, implementing a 13 min chromatography gradient with mobile phases of ammonium formate and methanol using positive mode electrospray. Several common drugs and metabolites can share the same mass and chemical formula among unrelated compounds, but they are structurally different. In this method, the LC-TOF-MS was able to resolve many isobaric compounds by accurate mass correlation within 15 ppm mass units and a narrow retention time interval of less than 10 s of separation. Drug recovery yields varied among spiked compounds, but resulted in overall robust area counts to deliver an average match score of 86 when compared to the retention time and mass of authentic standards. In summary, this method represents a rapid, enhanced screen for blood and urine specimens in postmortem, driving under the influence, and drug facilitated sexual assault forensic toxicology casework. PMID:23118149

Guale, Fessessework; Shahreza, Shahriar; Walterscheid, Jeffrey P; Chen, Hsin-Hung; Arndt, Crystal; Kelly, Anna T; Mozayani, Ashraf

2013-01-01

65

Rapid typing of bacteria using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry and pattern recognition software  

Microsoft Academic Search

Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) of intact microorganisms, also known as intact cell MALDI-TOF-MS (ICM-MS), has been shown to produce characteristic mass spectral fingerprints of moieties desorbed from the cell surface. ICM-MS spectra can be obtained in minutes after removal of a colony from a culture plate. The similarity of ICM-MS spectra of replicate samples and of

John J. Bright; Martin A. Claydon; Majeed Soufian; Derek B. Gordon

2002-01-01

66

Identification of putative biomarkers for toluene-degrading Burkholderia and pseudomonas by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and peptide mass fingerprinting.  

PubMed

The use of peptide mass fingerprinting with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was demonstrated to identify and phenotypically characterize toluene-degrading bacteria via biomarkers of degradation and taxonomical classification. Pseudomonas putida F1, P. mendocina KR1, and Burkholderia sp. JS150 were grown on toluene, extracted, electrophoretically separated, and analyzed by MALDI-TOF MS. Catabolic enzymes were identified and results substantiated using tandem MS. PMID:20622441

Hartmann, Erica M; Colquhoun, David R; Halden, Rolf U

2010-01-01

67

Top-down proteomic identification of furin-cleaved alpha-subunit of Shiga toxin 2 from Escherichia coli O157:H7 using MALDI-TOF-TOF-MS/MS  

Technology Transfer Automated Retrieval System (TEKTRAN)

A method has been developed to identify the alpha-subunit of shiga toxin 2 (alpha-Stx2) from Escherichia coli O157:H7 using matrix-assisted laser desorption/ionization time-of-flight-time-of-flight tandem mass spectrometry (MALDI-TOF-TOF-MS/MS) and top-down proteomics using web-based software develo...

68

Spontaneous-Desorption Ionizer for a TOF-MS  

NASA Technical Reports Server (NTRS)

A time-of-flight mass spectrometer (TOF-MS) like the one mentioned in the immediately preceding article has been retrofitted with an ionizer based on a surface spontaneous-desorption process. This ionizer includes an electron multiplier in the form of a microchannel plate (MCP). Relative to an ionizer based on a hot-filament electron source, this ionizer offers advantages of less power consumption and greater mechanical ruggedness. The current density and stability characteristics of the electron emission of this ionizer are similar to those of a filament-based ionizer. In tests of various versions of this ionizer in the TOF-MS, electron currents up to 100 nA were registered. Currents of microamperes or more - great enough to satisfy requirements in most TOFMS applications - could be obtained by use of MCPs different from those used in the tests, albeit at the cost of greater bulk. One drawback of this ionizer is that the gain of the MCP decreases as a function of the charge extracted thus far; the total charge that can be extracted over the operational lifetime is about 1 coulomb. An MCP in the ion-detector portion of the TOF-MS is subject to the same limitation.

Schultz, J. Albert

2006-01-01

69

MALDI-TOF MS of Trichoderma : a model system for the identification of microfungi  

Microsoft Academic Search

This investigation aimed to assess whether MALDI-TOF MS analysis of the proteome could be applied to the study of Trichoderma, a fungal genus selected because it includes many species and is phylogenetically well defined. We also investigated whether\\u000a MALDI-TOF MS analysis of peptide mass fingerprints would reveal apomorphies that could be useful in diagnosing species in\\u000a this genus. One hundred

Sophie De Respinis; Guido Vogel; Cinzia Benagli; Mauro Tonolla; Orlando Petrini; Gary J. Samuels

2010-01-01

70

Proton Transfer Reaction Time-of-Flight Mass Spectrometric (PTR-TOF-MS) determination of volatile organic compounds (VOCs) emitted from a biomass fire developed under stable nocturnal conditions  

NASA Astrophysics Data System (ADS)

Combustion of solid and liquid fuels is the largest source of potentially toxic volatile organic compounds (VOCs), which can strongly affect health and the physical and chemical properties of the atmosphere. Among combustion processes, biomass burning is one of the largest at global scale. We used a Proton Transfer Reaction “Time-of-Flight” Mass Spectrometer (PTR-TOF-MS), which couples high sensitivity with high mass resolution, for real-time detection of multiple VOCs emitted by burned hay and straw in a barn located near our measuring station. We detected 132 different organic ions directly attributable to VOCs emitted from the fire. Methanol, acetaldehyde, acetone, methyl vinyl ether (MVE), acetic acid and glycolaldehyde dominated the VOC mixture composition. The time-course of the 25 most abundant VOCs, representing ?85% of the whole mixture of VOCs, was associated with that of carbon monoxide (CO), carbon dioxide (CO2) and methane (CH4) emissions. The strong linear relationship between the concentrations of pyrogenic VOC and of a reference species (i.e. CO) allowed us to compile a list of emission ratios (ERs) and emission factors (EFs), but values of ER (and EF) were overestimated due to the limited mixing of the gases under the stable (non-turbulent) nocturnal conditions. In addition to the 25 most abundant VOCs, chemical formula and concentrations of the residual, less abundant VOCs in the emitted mixture were also estimated by PTR-TOF-MS. Furthermore, the evolution of the complex combustion process was described on the basis of the diverse types of pyrogenic gases recorded.

Brilli, Federico; Gioli, Beniamino; Ciccioli, Paolo; Zona, Donatella; Loreto, Francesco; Janssens, Ivan A.; Ceulemans, Reinhart

2014-11-01

71

Development of a Direct Headspace Collection Method from Arabidopsis Seedlings Using HS-SPME-GC-TOF-MS Analysis  

PubMed Central

Plants produce various volatile organic compounds (VOCs), which are thought to be a crucial factor in their interactions with harmful insects, plants and animals. Composition of VOCs may differ when plants are grown under different nutrient conditions, i.e., macronutrient-deficient conditions. However, in plants, relationships between macronutrient assimilation and VOC composition remain unclear. In order to identify the kinds of VOCs that can be emitted when plants are grown under various environmental conditions, we established a conventional method for VOC profiling in Arabidopsis thaliana (Arabidopsis) involving headspace-solid-phase microextraction-gas chromatography-time-of-flight-mass spectrometry (HS-SPME-GC-TOF-MS). We grew Arabidopsis seedlings in an HS vial to directly perform HS analysis. To maximize the analytical performance of VOCs, we optimized the extraction method and the analytical conditions of HP-SPME-GC-TOF-MS. Using the optimized method, we conducted VOC profiling of Arabidopsis seedlings, which were grown under two different nutrition conditions, nutrition-rich and nutrition-deficient conditions. The VOC profiles clearly showed a distinct pattern with respect to each condition. This study suggests that HS-SPME-GC-TOF-MS analysis has immense potential to detect changes in the levels of VOCs in not only Arabidopsis, but other plants grown under various environmental conditions. PMID:24957989

Kusano, Miyako; Iizuka, Yumiko; Kobayashi, Makoto; Fukushima, Atsushi; Saito, Kazuki

2013-01-01

72

Comparative analysis of Gram's stain, PNA-FISH and Sepsityper with MALDI-TOF MS for the identification of yeast direct from positive blood cultures.  

PubMed

Fungaemia diagnosis could be improved by reducing the time to identification of yeast from blood cultures. This study aimed to evaluate three rapid methods for the identification of yeast direct from blood cultures; Gram's stain analysis, the AdvanDX Peptide Nucleic Acid in Situ Hybridisation Yeast Traffic Light system (PNA-FISH YTL) and Bruker Sepsityper alongside matrix-assisted laser desorption ionisation time of flight mass spectrometry (MALDI-TOF MS). Fifty blood cultures spiked with a known single yeast strain were analysed by blinded operators experienced in each method. Identifications were compared with MALDI-TOF MS CHROMagar Candida culture and ITS rRNA sequence-based identifications. On first attempt, success rates of 96% (48/50) and 76% (36/50) were achieved using PNA-FISH YTL and Gram's stain respectively. MALDI-TOF MS demonstrated a success rate of 56% (28/50) when applying manufacturer's species log score thresholds and 76% (38/50) using in-house parameters, including lowering the species log score threshold to >1.5. In conclusion, PNA-FISH YTL demonstrated a high success rate successfully identifying yeast commonly encountered in fungaemia. Sepsityper(™) with MALDI-TOF MS was accurate but increased sensitivity is required. Due to the misidentification of commonly encountered yeast Gram's stain analysis demonstrated limited utility in this setting. PMID:24862948

Gorton, Rebecca L; Ramnarain, P; Barker, K; Stone, N; Rattenbury, S; McHugh, T D; Kibbler, C C

2014-10-01

73

Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Differentiation of the Dimorphic Fungal Species Paracoccidioides brasiliensis and Paracoccidioides lutzii.  

PubMed

Isolates of Paracoccidioides brasiliensis and Paracoccidioides lutzii, previously characterized by molecular techniques, were identified for the first time by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). All isolates were correctly identified, with log score values of >2.0. Thus, MALDI-TOF MS is a new tool for differentiating species of the genus Paracoccidioides. PMID:25631803

Nobrega de Almeida, João; Del Negro, Gilda M B; Grenfell, Rafaella C; Vidal, Monica S M; Thomaz, Danilo Y; de Figueiredo, Dulce S Y; Bagagli, Eduardo; Juliano, Luiz; Benard, Gil

2015-04-01

74

Evaluation of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry for species identification of Nonfermenting Gram-Negative Bacilli.  

PubMed

Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) to identify 396 Nonfermenting Gram-Negative Bacilli clinical isolates was evaluated in comparison with conventional phenotypic tests and/or molecular methods. MALDI-TOF MS identified to species level 256 isolates and to genus or complex level 112 isolates. It identified 29 genera including uncommon species. PMID:25765149

Almuzara, Marisa; Barberis, Claudia; Traglia, Germán; Famiglietti, Angela; Ramirez, Maria Soledad; Vay, Carlos

2015-05-01

75

Correlations between blood glucose and breath components from portable gas sensors and PTR-TOF-MS.  

PubMed

Acetone is one of the most abundant volatile compounds in the human breath and might be important for monitoring diabetic patients. Here, a portable acetone sensor consisting of flame-made, nanostructured, Si-doped WO3 sensing films was used to analyse the end tidal fraction of the breath (collected in Tedlar bags) from eight healthy volunteers after overnight fasting (morning) and after lunch (afternoon). After breath sampling, the gaseous components were also analysed by proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS), and each person's blood glucose level was measured. The portable sensor accurately detected the presence of acetone with fast response/recovery times (<12 s) and a high signal-to-noise ratio. Statistical analysis of the relationship between the PTR-TOF-MS measurements of breath gases (e.g., acetone, isoprene, ethanol and methanol), sensor response and the blood glucose level was performed for both sampling periods. The best correlations were found after overnight fasting (morning): in particular, between blood glucose level and breath acetone (Pearson's 0.98 and Spearman's 0.93). Whereas the portable sensor response correlated best with the blood glucose (Pearson's 0.96 and Spearman's 0.81) and breath acetone (Pearson's 0.92 and Spearman's 0.69). PMID:23959908

Righettoni, M; Schmid, A; Amann, A; Pratsinis, S E

2013-09-01

76

Detection of Ricin Intoxication in Mice Using Serum Peptide Profiling by MALDI-TOF/MS  

PubMed Central

Ricin toxin has been regarded as one of the most potent poisons in the plant kingdom, and there is no effective therapeutic countermeasure or licensed vaccine against it. Consequently, early detection of ricin intoxication is necessary. In this study, we took mice as test subjects, and used the technique of Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/MS) and ClinProt™ microparticle beads to set up an effective detection model with an accuracy of almost 100%. Eighty-two peaks in the mass range 1000–10,000 m/z were detected by ClinProTools software, and five different peaks with m/z of 4982.49, 1333.25, 1537.86, 4285.05 and 2738.88 had the greatest contribution to the accuracy and sensitivity of this model. They may therefore provide biomarkers for ricin intoxication. PMID:23202975

Zhao, Siyan; Liu, Wen-Sen; Wang, Meng; Li, Jiping; Sun, Yucheng; Li, Nan; Hou, Feng; Wan, Jia-Yu; Li, Zhongyi; Qian, Jun; Liu, Linna

2012-01-01

77

OLIGOSACCHARIDE STRUCTURES STUDIED BY HYDROGEN-DEUTERIUM EXCHANGE (HX) AND MALDI-TOF MASS SPECTROMETRY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hydrogen-deuterium exchange matrix-assisted laser desorption/ionization - time-of-flight mass spectrometry (HX-MALDI-TOF MS) is reported for the first time for the determination of exchangeable protons in diverse oligosaccharide and glycoconjugate structures. The method is generally analogous to th...

78

Identification of Bacteria Using Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry  

ERIC Educational Resources Information Center

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS or simply MALDI) has become ubiquitous in the identification and analysis of biomacromolecules. As a technique that allows for the molecular weight determination of otherwise nonvolatile molecules, MALDI has had a profound impact in the molecular…

Kedney, Mollie G.; Strunk, Kevin B.; Giaquinto, Lisa M.; Wagner, Jennifer A.; Pollack, Sidney; Patton, Walter A.

2007-01-01

79

MALDI-TOF Mass Spectrometry of Naturally-Occurring Mixtures of Mono- and Di-rhamnolipids  

Technology Transfer Automated Retrieval System (TEKTRAN)

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been developed for high-throughput screening of naturally-occurring mixtures of rhamnolipids from Pseudomonas spp. Mono- and di-rhamnolipids are readily distinguished by characteristic molecular adduct i...

80

Advances in quantitative hepcidin measurements by time-of-flight mass spectrometry  

Microsoft Academic Search

Assays for the detection of the iron regulatory hormone hepcidin in plasma or urine have not yet been widely available, whereas quantitative comparisons between hepcidin levels in these different matrices were thus far even impossible due to technical restrictions. To circumvent these limitations, we here describe several advances in time-of flight mass spectrometry (TOF MS), the most important of which

Dorine W. Swinkels; Domenico Girelli; Coby Laarakkers; Joyce Kroot; Natascia Campostrini; Erwin H. J. M. Kemna; Harold Tjalsma

2008-01-01

81

Quercetin-3-O-?-D-glucopyranosyl-(4?1)-?-L-rhamnoside metabolites in the rat using UPLC-Q-TOF/MS.  

PubMed

Ultraperformance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MS) and the Metabolynx™ software, combined with mass defect filtering, were applied to identity the metabolites of quercetin-3-O-?-D-gluco-pyranosyl-(4?1)-?-L-rhamnoside (QGR) in rats after intravenous administration. MS(E) was used for simultaneous acquisition of precursor ion information and fragment ion data at high and low collision energy in one analytical run, which facilitated the rapid structural characterization of eight metabolites in rat plasma, urine and bile. The results indicated that methylation and glucuronidation were the major metabolic pathways of QGR in vivo. The present study provided important information about the metabolism of QGR which will be useful for fully understanding the mechanism of action of this compound. Furthermore, this work demonstrated the potential of the UPLC-Q-TOF/MS approach using Metabolynx for rapid and automated research of the metabolites of natural products. PMID:25263985

Yao, Xin; Zhou, Gui-Sheng; Tang, Yu-Ping; Shang, Er-Xin; Guo, Jian-Ming; Qian, Da-Wei; Duan, Jin-Ao

2014-09-01

82

A case report of Mycoplasma hominis brain abscess identified by MALDI-TOF mass spectrometry.  

PubMed

We report the case of a 43-year-old man with a Mycoplasma hominis brain abscess occurring after a cranial trauma, which was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The presence of colonies on classic blood agar plates and the use of MALDI-TOF MS, a valuable diagnostic tool that identified M. hominis due to its presence in the VITEK MS database, allowed the rapid diagnosis of this infection. PMID:25449252

Pailhoriès, H; Rabier, V; Eveillard, M; Mahaza, C; Joly-Guillou, M-L; Chennebault, J-M; Kempf, M; Lemarié, C

2014-12-01

83

Detector response in time-of-flight mass spectrometry at high pulse repetition frequencies  

NASA Technical Reports Server (NTRS)

Dead time effects in chevron configured dual microchannel plates (MCPs) are investigated. Response times are determined experimentally for one chevron-configured dual MCP-type detector and two discrete dynode-type electron multipliers with 16 and 23 resistively divided stages. All of these detectors are found to be suitable for time-of-flight mass spectrometry (TOF MS), yielding 3-6-ns (FWHM) response times triggered on a single ion pulse. It is concluded that, unless there are viable solutions to overcome dead time disadvantages for continuous dynode detectors, suitable discrete dynode detectors for TOF MS appear to have a significant advantage for high repetition rate operation.

Gulcicek, Erol E.; Boyle, James G.

1993-01-01

84

LC-TOF/MS determination of phthalates in edible salts from food markets in Korea.  

PubMed

Residual quantities of 12 phthalates have been monitored in edible salts (raw salts, refined salts, refined salts with additives and baked salts) available in Korean food markets. Liquid-liquid extraction followed by liquid chromatography time-of-flight mass spectrometry (LC-TOF/MS) was used to analyse the samples. The method was validated and showed linear correlation (R² > 0.996) in the range 0.5-100 ng g?¹ for all target analytes. Recoveries were 85.9-108.4%, except for diethyl phthalate (DEP). Relative standard deviations (RSDs) were 2.7-6.0% and the limits of detection (LODs) were 1.2-2.8 ng g?¹. Although the contamination of phthalates in salt would be trivial in comparison to those of other main foods and below the reference dose of the Chronic Oral Exposure recommended by US-EPA, the availability of reference data could be valuable for food chemists and salt manufacturers. PMID:24779906

Dirwono, Warnadi; Nam, Yun Sik; Park, Hyun-Mee; Lee, Kang-Bong

2013-01-01

85

Characterization of mustard seeds and paste by DART ionization with time-of-flight mass spectrometry.  

PubMed

Direct analysis in real time (DART) is a novel technique with great potential for rapid screening analysis. The DART ionization method coupled with high-resolution time-of-flight mass spectrometry (TOF-MS) has been used for characterization of mustard seeds and table mustard. The possibility to use DART to analyse glucosinolates was confirmed on determination of sinalbin (4-hydroxybenzyl glucosinolate). The DART-TOF-MS method was optimized and validated. A set of samples of mustard seeds and mustard products was analyzed. High-performance liquid chromatography and DART-TOF-MS were used to determine glucosinolates in mustard seeds and compared. The correlation equation between these methods was DART?=?0.797*HPLC?+?6.987, R(2) ?=?0.972. The DART technique seems to be a suitable method for evaluation of the quality of mustard seeds and mustard products. PMID:25230177

Prchalová, Jana; Kova?ík, František; Šev?ík, Rudolf; ?ížková, Helena; Rajchl, Aleš

2014-09-01

86

Probing Combustion Chemistry in a Miniature Shock Tube with Synchrotron VUV Photo Ionization Mass Spectrometry.  

PubMed

Tunable synchrotron-sourced photoionization time-of-flight mass spectrometry (PI-TOF-MS) is an important technique in combustion chemistry, complementing lab-scale electron impact and laser photoionization studies for a wide variety of reactors, typically at low pressure. For high-temperature and high-pressure chemical kinetics studies, the shock tube is the reactor of choice. Extending the benefits of shock tube/TOF-MS research to include synchrotron sourced PI-TOF-MS required a radical reconception of the shock tube. An automated, miniature, high-repetition-rate shock tube was developed and can be used to study high-pressure reactive systems (T > 600 K, P < 100 bar) behind reflected shock waves. In this paper, we present results of a PI-TOF-MS study at the Advanced Light Source at Lawrence Berkeley National Laboratory. Dimethyl ether pyrolysis (2% CH3OCH3/Ar) was observed behind the reflected shock (1400 < T5 < 1700 K, 3 < P5 < 16 bar) with ionization energies between 10 and 13 eV. Individual experiments have extremely low signal levels. However, product species and radical intermediates are well-resolved when averaging over hundreds of shots, which is ordinarily impractical in conventional shock tube studies. The signal levels attained and data throughput rates with this technique are comparable to those with other synchrotron-based PI-TOF-MS reactors, and it is anticipated that this high pressure technique will greatly complement those lower pressure techniques. PMID:25594229

Lynch, Patrick T; Troy, Tyler P; Ahmed, Musahid; Tranter, Robert S

2015-02-17

87

High throughput identification of clinical isolates of Staphylococcus aureus using MALDI-TOF-MS of intact cells.  

PubMed

Staphylococcus aureus remains an important human pathogen responsible for a high burden of disease in healthcare and community settings. The emergence of multidrug-resistant strains is of increasing concern world-wide. The identification of S. aureus is currently based upon phenotypic and genotypic methods. Here, an alternative approach involving mass spectral analysis of surface-associated proteins of intact bacterial cells by matrix-assisted laser desorption/ionisation time of flight mass spectrometry (MALDI-TOF-MS) was investigated using 95 isolates obtained directly from a clinical laboratory at The Royal London Hospital and 39 isolates from the Staphylococcal Reference Unit, Health Protection Agency, London. Results obtained indicate that clinical isolates share many common mass ions with-type/reference strains which allowed their correct identification when searched against a comprehensive database that has been in the process of development for several years. The existing database contains more than 5000 profiles of various bacterial pathogens, but comprises mainly type or reference strains. The MicrobeLynx software successfully identified all isolates to the correct genus and all but four to the correct species. These were misidentified in the first instance due to contamination or low mass ion intensity but once the cultures were purified and re-analysed they were confirmed as S. aureus by both MALDI-TOF-MS and 16S rRNA sequence analysis. The high percentage of correct identifications coupled with the high speed and the minimal sample preparation required, indicate that MALDI-TOF-MS has the potential to perform high throughput identification of clinical isolates of S. aureus despite the inherent diversity of this species. The method is, however, only reproducible if variable parameters such as sample preparation, media, growth condition, etc. are standardised. PMID:19460316

Rajakaruna, Lakshani; Hallas, Gillian; Molenaar, Linda; Dare, Diane; Sutton, Helen; Encheva, Vesela; Culak, Renata; Innes, Ingrid; Ball, Graham; Sefton, Armine M; Eydmann, Melvin; Kearns, Angela M; Shah, Haroun N

2009-07-01

88

A simple algorithm improves mass accuracy to 50-100 ppm for delayed extraction linear MALDI-TOF mass spectrometry  

Microsoft Academic Search

A simple mathematical technique for improving mass calibration accuracy of linear delayed extraction matrix assisted laser desorption ionization time-of-flight mass spectrometry (DE MALDI-TOF MS) spectra is presented. The method involves fitting a parabola to a plot of Dm vs. mass data where Dm is the difference between the theoretical mass of calibrants and the mass obtained from a linear relationship

Christopher A. Hack; W. Henry Benner

2001-01-01

89

Differentiation of Bacillus pumilus and Bacillus safensis using MALDI-TOF-MS.  

PubMed

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) despite being increasingly used as a method for microbial identification, still present limitations in which concerns the differentiation of closely related species. Bacillus pumillus and Bacillus safensis, are species of biotechnological and pharmaceutical significance, difficult to differentiate by conventional methodologies. In this study, using a well-characterized collection of B. pumillus and B. safensis isolates, we demonstrated the suitability of MALDI-TOF-MS combined with chemometrics to accurately and rapidly identify them. Moreover, characteristic species-specific ion masses were tentatively assigned, using UniProtKB/Swiss-Prot and UniProtKB/TrEMBL databases and primary literature. Delineation of B. pumilus (ions at m/z 5271 and 6122) and B. safensis (ions at m/z 5288, 5568 and 6413) species were supported by a congruent characteristic protein pattern. Moreover, using a chemometric approach, the score plot created by partial least square discriminant analysis (PLSDA) of mass spectra demonstrated the presence of two individualized clusters, each one enclosing isolates belonging to a species-specific spectral group. The generated pool of species-specific proteins comprised mostly ribosomal and SASPs proteins. Therefore, in B. pumilus the specific ion at m/z 5271 was associated with a small acid-soluble spore protein (SASP O) or with 50S protein L35, whereas in B. safensis specific ions at m/z 5288 and 5568 were associated with SASP J and P, respectively, and an ion at m/z 6413 with 50S protein L32. Thus, the resulting unique protein profile combined with chemometric analysis, proved to be valuable tools for B. pumilus and B. safensis discrimination, allowing their reliable, reproducible and rapid identification. PMID:25314655

Branquinho, Raquel; Sousa, Clara; Lopes, João; Pintado, Manuela E; Peixe, Luísa V; Osório, Hugo

2014-01-01

90

Differentiation of Bacillus pumilus and Bacillus safensis Using MALDI-TOF-MS  

PubMed Central

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) despite being increasingly used as a method for microbial identification, still present limitations in which concerns the differentiation of closely related species. Bacillus pumillus and Bacillus safensis, are species of biotechnological and pharmaceutical significance, difficult to differentiate by conventional methodologies. In this study, using a well-characterized collection of B. pumillus and B. safensis isolates, we demonstrated the suitability of MALDI-TOF-MS combined with chemometrics to accurately and rapidly identify them. Moreover, characteristic species-specific ion masses were tentatively assigned, using UniProtKB/Swiss-Prot and UniProtKB/TrEMBL databases and primary literature. Delineation of B. pumilus (ions at m/z 5271 and 6122) and B. safensis (ions at m/z 5288, 5568 and 6413) species were supported by a congruent characteristic protein pattern. Moreover, using a chemometric approach, the score plot created by partial least square discriminant analysis (PLSDA) of mass spectra demonstrated the presence of two individualized clusters, each one enclosing isolates belonging to a species-specific spectral group. The generated pool of species-specific proteins comprised mostly ribosomal and SASPs proteins. Therefore, in B. pumilus the specific ion at m/z 5271 was associated with a small acid-soluble spore protein (SASP O) or with 50S protein L35, whereas in B. safensis specific ions at m/z 5288 and 5568 were associated with SASP J and P, respectively, and an ion at m/z 6413 with 50S protein L32. Thus, the resulting unique protein profile combined with chemometric analysis, proved to be valuable tools for B. pumilus and B. safensis discrimination, allowing their reliable, reproducible and rapid identification. PMID:25314655

Branquinho, Raquel; Sousa, Clara; Lopes, João; Pintado, Manuela E.; Peixe, Luísa V.; Osório, Hugo

2014-01-01

91

Accurate identification of Culicidae at aquatic developmental stages by MALDI-TOF MS profiling.  

PubMed

BackgroundThe identification of mosquito vectors is generally based on morphological criteria, but for aquatic stages, morphological characteristics may be missing, leading to incomplete or incorrect identification. The high cost of molecular biology techniques requires the development of an alternative strategy. In the last decade, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) profiling has proved to be efficient for arthropod identification at the species level.MethodsTo investigate the usefulness of MALDI-TOF MS for the identification of mosquitoes at aquatic stages, optimizations of sample preparation, diet, body parts and storage conditions were tested. Protein extracts of whole specimens from second larval stage to pupae were selected for the creation of a reference spectra database. The database included a total of 95 laboratory-reared specimens of 6 mosquito species, including Anopheles gambiae (S form), Anopheles coluzzi (M form), Culex pipiens pipiens, Culex pipiens molestus, Aedes aegypti and 2 colonies of Aedes albopictus.ResultsThe present study revealed that whole specimens at aquatic stages produced reproducible and singular spectra according to the mosquito species. Moreover, MS protein profiles appeared weakly affected by the diet provided. Despite the low diversity of some MS profiles, notably for cryptic species, clustering analyses correctly classified all specimens tested at the species level followed by the clustering of early vs. late aquatic developmental stages. Discriminant mass peaks were recorded for the 6 mosquito species analyzed at larval stage 3 and the pupal stage. Querying against the reference spectra database of 149 new specimens at different aquatic stages from the 6 mosquito species revealed that 147 specimens were correctly identified at the species level and that early and late developmental stages were also distinguished.ConclusionsThe present work highlights that MALDI-TOF MS profiling may be useful for the rapid and reliable identification of mosquito species at aquatic stages. With this proteomic tool, it becomes now conceivable to survey mosquito breeding sites prior to the mosquitoes¿ emergence and to adapt anti-vectorial measures according to the mosquito fauna detected. PMID:25442218

Dieme, Constentin; Yssouf, Amina; Vega-Rúa, Anubis; Berenger, Jean-Michel; Failloux, Anna-Bella; Raoult, Didier; Parola, Philippe; Almeras, Lionel

2014-12-01

92

Mass spectrometry.  

NASA Technical Reports Server (NTRS)

Review of the current state of mass spectrometry, indicating its unique importance for advanced scientific research. Mass spectrometry applications in computer techniques, gas chromatography, ion cyclotron resonance, molecular fragmentation and ionization, and isotope labeling are covered. Details are given on mass spectrometry applications in bio-organic chemistry and biomedical research. As the subjects of these applications are indicated alkaloids, carbohydrates, lipids, terpenes, quinones, nucleic acid components, peptides, antibiotics, and human and animal metabolisms. Particular attention is given to the mass spectra of organo-inorganic compounds, inorganic mass spectrometry, surface phenomena such as secondary ion and electron emission, and elemental and isotope analysis. Further topics include mass spectrometry in organic geochemistry, applications in geochronology and cosmochemistry, and organic mass spectrometry.

Burlingame, A. L.; Johanson, G. A.

1972-01-01

93

Multiplexed Ion Mobility Spectrometry - Orthogonal Time-Of-Flight Mass Spectrometry  

SciTech Connect

Ion mobility spectrometry (IMS) coupled to orthogonal time-of-flight mass spectrometry (TOF) has shown significant promise for the characterization of complex biological mixtures. The enormous complexity of biological samples (e.g. from proteomics) and the need for both biological and technical analysis replicates imposes major challenges for multidimensional separation platforms in regard to both sensitivity and sample throughput. A major potential attraction of the IMS-TOF MS platform is separation speeds exceeding that of conventional condensed-phase separations by orders of magnitude. Known limitations of the IMS-TOF MS platforms that presently mitigate this attraction include the need for extensive signal averaging due to factors that include significant ion losses in the IMS-TOF interface and an ion utilization efficiency of less than ~1% with continuous ion sources (e.g. ESI). We have developed a new multiplexed ESI-IMS-TOF mass spectrometer that enables lossless ion transmission through the IMS-TOF as well as a utilization efficiency of >50% for ions from the ESI source. Initial results with a mixture of peptides show a ~10-fold increase in signal-to-noise ratio with the multiplexed approach compared to a signal averaging approach, with no reduction in either IMS or TOF MS resolution.

Belov, Mikhail E.; Buschbach, Michael A.; Prior, David C.; Tang, Keqi; Smith, Richard D.

2007-03-15

94

Direct screening of herbal blends for new synthetic cannabinoids by MALDI-TOF MS.  

PubMed

Since 2004, a number of herbal blends containing different synthetic compounds mimicking the pharmacological activity of cannabinoids and displaying a high toxicological potential have appeared in the market. Their availability is mainly based on the so-called "e-commerce", being sold as legal alternatives to cannabis and cannabis derivatives. Although highly selective, sensitive, accurate, and quantitative methods based on GC-MS and LC-MS are available, they lack simplicity, rapidity, versatility and throughput, which are required for product monitoring. In this context, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) offers a simple and rapid operation with high throughput. Thus, the aim of the present work was to develop a MALDI-TOF MS method for the rapid qualitative direct analysis of herbal blend preparations for synthetic cannabinoids to be used as front screening of confiscated clandestine preparations. The sample preparation was limited to herbal blend leaves finely grinding in a mortar and loading onto the MALDI plate followed by addition of 2 µl of the matrix/surfactant mixture [?-cyano-4-hydroxy-cinnamic acid/cetyltrimethylammonium bromide (CTAB)]. After drying, the sample plate was introduced into the ion source for analysis. MALDI-TOF conditions were as follows: mass spectra were analyzed in the range m/z 150-550 by averaging the data from 50 laser shots and using an accelerating voltage of 20?kV. The described method was successfully applied to the screening of 31 commercial herbal blends, previously analyzed by GC-MS. Among the samples analyzed, 21 contained synthetic cannabinoids (namely JWH-018, JWH-073, JWH-081, JWH-250, JWH-210, JWH-019, and AM-694). All the results were in agreement with GC-MS, which was used as the reference technique. PMID:22282100

Gottardo, Rossella; Chiarini, Anna; Dal Prà, Ilaria; Seri, Catia; Rimondo, Claudia; Serpelloni, Giovanni; Armato, Ubaldo; Tagliaro, Franco

2012-01-01

95

Early diagnosis of Irkut virus infection using magnetic bead-based serum peptide profiling by MALDI-TOF MS in a mouse model.  

PubMed

Early diagnosis is important for the prompt post-exposure prophylaxis of lyssavirus infections. To diagnose Irkut virus (IRKV) infection during incubation in mice, a novel method using magnetic bead-based serum peptide profiling by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been established. For this test, serum peptides were concentrated by adsorption to and elution from the magnetic bead-based weak cation ion exchanger. Mass spectrograms obtained by MALDI-TOF MS were analyzed using ClinProTools bioinformatics software. Construction of the diagnostic model was performed using serum samples from mice infected with IRKV and rabies virus (RABV) BD06, Flury-LEP, and SRV9 (as controls). The method accurately diagnosed sera 2, 4 and 8 days after IRKV and RABV infections. The sensitivity, specificity, and total accuracy of diagnosis were 86.7%, 95.2%, and 92.9%, respectively. However, IRKV could not be differentiated from RABV 1 day after infection. The results of the present study indicate that serum peptide profiling by MALDI-TOF MS is a promising technique for the early clinical diagnosis of lyssavirus infections and needs to be further tested in humans and farm animals. PMID:24670473

Li, Nan; Liu, Ye; Hao, Zhuo; Zhang, Shoufeng; Hu, Rongliang; Li, Jiping

2014-01-01

96

Reducing time to identification of positive blood cultures with MALDI-TOF MS analysis after a 5-h subculture.  

PubMed

Speeding up the turn-around time of positive blood culture identifications is essential in order to optimize the treatment of septic patients. Several sample preparation techniques have been developed allowing direct matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) identification of positive blood cultures. Yet, the hands-on time restrains their routine workflow. In this study, we evaluated an approach whereby MALDI-TOF MS identification without any additional steps was carried out on short subcultured colonies from positive blood bottles with the objective of allowing results reporting on the day of positivity detection. Over a 7-month period in 2012, positive blood cultures detected by 9 am with an automated system were inoculated onto a Columbia blood agar and processed after a 5-h incubation on a MALDI-TOF MicroFlex platform (Bruker Daltonik GmbH). Single-spotted colonies were covered with 1 ?l formic acid and 1 ?l matrix solution. The results were compared to the validated identification techniques. A total of 925 positive blood culture bottles (representing 470 bacteremic episodes) were included. Concordant identification was obtained in 727 (81.1 %) of the 896 monomicrobial blood cultures, with failure being mostly observed with anaerobes and yeasts. In 17 episodes of polymicrobic bacteremia, the identification of one of the two isolates was achieved in 24/29 (82.7 %) positive cultures. Routine implementation of MALDI-TOF MS identification on young positive blood subcultures provides correct results to the clinician in more than 80 % of the bacteremic episodes and allows access to identification results on the day of blood culture positivity detection, potentially accelerating the implementation of targeted clinical treatments. PMID:25252627

Verroken, A; Defourny, L; Lechgar, L; Magnette, A; Delmée, M; Glupczynski, Y

2015-02-01

97

MALDI-TOF mass spectrometry applied to identifying species of insect-pathogenic fungi from the Metarhizium anisopliae complex  

Technology Transfer Automated Retrieval System (TEKTRAN)

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has proven to be a powerful tool for taxonomic resolution of microorganisms. In this proof-of-concept study, we assessed the effectiveness of this technique to track the current gene sequence-based phylogenet...

98

Sodiation as a tool for enhancing the diagnostic value of MALDI-TOF/TOF-MS spectra of complex astaxanthin ester mixtures from Haematococcus pluvialis.  

PubMed

The microalga Haematococcus pluvialis produces the pigment astaxanthin mainly in esterified form with a multitude of fatty acids, which results in a complex mixture of carotenol mono- and diesters. For rapid fingerprinting of these esters, matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF/TOF-MS) might be an alternative to traditional chromatographic separation combined with MS. Investigation of ionization and fragmentation of astaxanthin mono- and diester palmitate standards in MALDI-TOF/TOF-MS showed that sodium adduct parent masses [M?+?Na](+) gave much simpler MS(2) spectra than radical / protonated [M](+?) / [M?+?H](+) parents. [M?+?Na](+) fragments yielded diagnostic polyene-specific eliminations and fatty acid neutral losses, whereas [M](+?) / [M?+?H](+) fragmentation resulted in a multitude of non-diagnostic daughters. For diesters, a benzonium fragment, formed by polyene elimination, was required for identification of the second fatty acid attached to the astaxanthin backbone. Parents were forced into [M?+?Na](+) ionization by addition of sodium acetate, and best signal-to-noise ratios were obtained in the 0.1 to 1.0?mM range. This method was applied to fingerprinting astaxanthin esters in a crude H. pluvialis extract. Prior to MALDI-TOF/TOF-MS, the extract was fractionated by normal phase Flash chromatography to obtain fractions enriched in mono- and diesters and to remove pheophytin a, which compromised monoester signals. All 12 types of all-trans esterified esters found in LC were identified with MALDI-TOF/TOF-MS, with the exception of two minor monoesters. PMID:23832943

Weesepoel, Yannick; Vincken, Jean-Paul; Pop, Raluca Maria; Liu, Kun; Gruppen, Harry

2013-07-01

99

Neutral particle mass spectrometry with nanomechanical systems  

NASA Astrophysics Data System (ADS)

Current approaches to mass spectrometry (MS) require ionization of the analytes of interest. For high-mass species, the resulting charge state distribution can be complex and difficult to interpret correctly. Here, using a setup comprising both conventional time-of-flight MS (TOF-MS) and nano-electromechanical systems-based MS (NEMS-MS) in situ, we show directly that NEMS-MS analysis is insensitive to charge state: the spectrum consists of a single peak whatever the species’ charge state, making it significantly clearer than existing MS analysis. In subsequent tests, all the charged particles are electrostatically removed from the beam, and unlike TOF-MS, NEMS-MS can still measure masses. This demonstrates the possibility to measure mass spectra for neutral particles. Thus, it is possible to envisage MS-based studies of analytes that are incompatible with current ionization techniques and the way is now open for the development of cutting-edge system architectures with unique analytical capability.

Sage, Eric; Brenac, Ariel; Alava, Thomas; Morel, Robert; Dupré, Cécilia; Hanay, Mehmet Selim; Roukes, Michael L.; Duraffourg, Laurent; Masselon, Christophe; Hentz, Sébastien

2015-03-01

100

Neutral particle mass spectrometry with nanomechanical systems  

PubMed Central

Current approaches to mass spectrometry (MS) require ionization of the analytes of interest. For high-mass species, the resulting charge state distribution can be complex and difficult to interpret correctly. Here, using a setup comprising both conventional time-of-flight MS (TOF-MS) and nano-electromechanical systems-based MS (NEMS-MS) in situ, we show directly that NEMS-MS analysis is insensitive to charge state: the spectrum consists of a single peak whatever the species’ charge state, making it significantly clearer than existing MS analysis. In subsequent tests, all the charged particles are electrostatically removed from the beam, and unlike TOF-MS, NEMS-MS can still measure masses. This demonstrates the possibility to measure mass spectra for neutral particles. Thus, it is possible to envisage MS-based studies of analytes that are incompatible with current ionization techniques and the way is now open for the development of cutting-edge system architectures with unique analytical capability. PMID:25753929

Sage, Eric; Brenac, Ariel; Alava, Thomas; Morel, Robert; Dupré, Cécilia; Hanay, Mehmet Selim; Roukes, Michael L.; Duraffourg, Laurent; Masselon, Christophe; Hentz, Sébastien

2015-01-01

101

Neutral particle mass spectrometry with nanomechanical systems.  

PubMed

Current approaches to mass spectrometry (MS) require ionization of the analytes of interest. For high-mass species, the resulting charge state distribution can be complex and difficult to interpret correctly. Here, using a setup comprising both conventional time-of-flight MS (TOF-MS) and nano-electromechanical systems-based MS (NEMS-MS) in situ, we show directly that NEMS-MS analysis is insensitive to charge state: the spectrum consists of a single peak whatever the species' charge state, making it significantly clearer than existing MS analysis. In subsequent tests, all the charged particles are electrostatically removed from the beam, and unlike TOF-MS, NEMS-MS can still measure masses. This demonstrates the possibility to measure mass spectra for neutral particles. Thus, it is possible to envisage MS-based studies of analytes that are incompatible with current ionization techniques and the way is now open for the development of cutting-edge system architectures with unique analytical capability. PMID:25753929

Sage, Eric; Brenac, Ariel; Alava, Thomas; Morel, Robert; Dupré, Cécilia; Hanay, Mehmet Selim; Roukes, Michael L; Duraffourg, Laurent; Masselon, Christophe; Hentz, Sébastien

2015-01-01

102

A SELDI-TOF-MS study in Lacunar Stroke with Subsequent Haptoglobin Phenotyping.  

PubMed

Using Surface-Enhanced Laser Desorption / Ionization Time-of-Flight Mass Spectrometry (SELDI-TOF-MS), we aimed to detect differences in protein profile in serum samples of two lacunar stroke subtypes. SELDI-TOF-MS, followed by protein identification, was performed in samples of 8 first-ever lacunar stroke patients with MR imaging showing a single symptomatic lacunar lesion (type 1), and 8 with multiple additional "silent" lacunar lesions and extensive white matter lesions (type 2). A 16 kDa protein, identified as alpha-2-chain of haptoglobin (Hp), was found to be overrepresented in type 1 compared to type 2 (peak intensity 12.5 vs. 5.0; p=0.02). As a polymorphism with two alleles, Hp-1 and Hp 2, determines the presence of alpha-1 and/or alpha-2-chains in the Hp-molecule, Hp phenotypic analysis was performed. Hp 1 : Hp-2 allele frequency was 0.562 : 0.438 in type 1 and 0.812 : 0.188 in type 2 (population reference approximately 0.4 : 0.6). We conclude that the overrepresentation of the alpha-2-chain in lacunar stroke type 1 compared to type 2 relates to a higher Hp-2 allele frequency in the former. Yet, compared to population reference, the phenotype distribution in both patient groups deviates towards a high Hp-1 allele frequency. Our findings suggest a role for the Hp gene in the etiology of cerebral small vessel disease. Larger studies are now needed to explore this new candidate gene. PMID:18473824

Staals, Julie; Bons, Judith A P; van Oostenbrugge, Robert J; Knottnerus, Iris L H; van Dieijen-Visser, Marja P; Bouwman, Freek G; Mariman, Edwin C; Delanghe, Joris R; Lodder, Jan; Wodzig, Will K W H

2008-05-01

103

Discovery of serum protein biomarkers in rheumatoid arthritis using MALDI-TOF-MS combined with magnetic beads.  

PubMed

The aim of this study was to discover potential biomarkers for rheumatoid arthritis (RA) using Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry combined with magnetic beads. Proteomic fingerprint technology combining magnetic beads with MALDI-TOF-MS was used to profile and compare the proteomes in serum samples from 60 patients with RA, 35 patients with osteoarthritis and 36 healthy controls. The proteomic pattern associated with RA was identified by Biomarker Patterns Software. Model of biomarkers was constructed and evaluated through the Biomarker Patterns Software. A total of 33 discriminative peaks were identified to be related with RA, in which the 5 peaks with the mass-charge ratio (m/z) peaks at 15,715.5, 7,771.4, 8,959.4, 8,469.8 and 8,710.8 Da were used to construct a model for the diagnosis of RA by pattern recognition software. The blind testing data indicated a sensitivity of 86.7% and a specificity of 90.0% in RA diagnosis. These results demonstrated that potential protein biomarkers for RA could be discovered in serum by MALDI-TOF-MS combined with WCX magnetic beads. The diagnosis mode tree based on the five candidate biomarkers could provide a powerful and reliable diagnostic method for RA with high sensitivity and specificity. PMID:21922190

Zhang, Xiaoxue; Yuan, Zhaolin; Shen, Bo; Zhu, Min; Liu, Chibo; Xu, Wei

2012-09-01

104

High Throughput Detection of Tetracycline Residues in Milk Using Graphene or Graphene Oxide as MALDI-TOF MS Matrix  

NASA Astrophysics Data System (ADS)

In this work, a new pre-analysis method for tetracyclines (TCs) detection from the milk samples was established. As a good accomplishment for the existing accurate quantification strategies for TCs detection, the new pre-analysis method was demonstrated to be simple, sensitive, fast, cost effective, and high throughput, which would do a great favor to the routine quality pre-analysis of TCs from milk samples. Graphene or graphene oxide was utilized, for the first time, as a duel-platform to enrich and detect the TCs by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). All together, four TCs were chosen as models: tetracycline, oxytetracycline, demeclocycline, and chlortetracycline. Due to the excellent electronic, thermal, and mechanical properties, graphene and graphene oxide were successfully applied as matrices for MALDI-TOF MS with free background inference in low mass range. Meanwhile, graphene or graphene oxide has a large surface area and strong interaction force with the analytes. By taking the advantage of these features, TCs were effectively enriched with the limit of detection (LOD) as low as 2 nM.

Liu, Junyan; Liu, Yang; Gao, Mingxia; Zhang, Xiangmin

2012-08-01

105

Comparison of MALDI-TOF MS, Housekeeping Gene Sequencing, and 16S rRNA Gene Sequencing for Identification of Aeromonas Clinical Isolates  

PubMed Central

Purpose The genus Aeromonas is a pathogen that is well known to cause severe clinical illnesses, ranging from gastroenteritis to sepsis. Accurate identification of A. hydrophila, A. caviae, and A. veronii is important for the care of patients. However, species identification remains difficult using conventional methods. The aim of this study was to compare the accuracy of different methods of identifying Aeromonas at the species level: a biochemical method, matrix-assisted laser desorption ionization mass spectrometry-time of flight (MALDI-TOF MS), 16S rRNA sequencing, and housekeeping gene sequencing (gyrB, rpoB). Materials and Methods We analyzed 65 Aeromonas isolates recovered from patients at a university hospital in Korea between 1996 and 2012. The isolates were recovered from frozen states and tested using the following four methods: a conventional biochemical method, 16S rRNA sequencing, housekeeping gene sequencing with phylogenetic analysis, and MALDI-TOF MS. Results The conventional biochemical method and 16S rRNA sequencing identified Aeromonas at the genus level very accurately, although species level identification was unsatisfactory. MALDI-TOF MS system correctly identified 60 (92.3%) isolates at the species level and an additional four (6.2%) at the genus level. Overall, housekeeping gene sequencing with phylogenetic analysis was found to be the most accurate in identifying Aeromonas at the species level. Conclusion The most accurate method of identification of Aeromonas to species level is by housekeeping gene sequencing, although high cost and technical difficulty hinder its usage in clinical settings. An easy-to-use identification method is needed for clinical laboratories, for which MALDI-TOF MS could be a strong candidate. PMID:25684008

Shin, Hee Bong; Yoon, Jihoon; Lee, Yangsoon; Kim, Myung Sook

2015-01-01

106

Extraction and sequencing of human and Neanderthal mature enamel proteins using MALDI-TOF/TOF MS  

E-print Network

Extraction and sequencing of human and Neanderthal mature enamel proteins using MALDI-TOF/TOF MS Enamel Neanderthal MALDI-TOF-TOF a b s t r a c t We report here the first results of a method to extract and sequence mature enamel proteins from modern human and Neanderthal tooth enamel. Using MALDI-TOF/TOF mass

Smith, Tanya M.

107

Detection of an Extended Human Volatome with Comprehensive Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry  

PubMed Central

Background Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOF MS) has been proposed as a powerful new tool for multidimensional analysis of complex chemical mixtures. We investigated GCxGC-TOF MS as a new method for identifying volatile organic compounds (VOCs) in normal human breath. Methods Samples of alveolar breath VOCs and ambient room air VOC were collected with a breath collection apparatus (BCA) onto separate sorbent traps from 34 normal healthy volunteers (mean age = 40 yr, SD = 17 yr, male/female = 19/15). VOCs were separated on two serial capillary columns separated by a cryogenic modulator, and detected with TOF MS. The first and second dimension columns were non-polar and polar respectively. Results BCA collection combined with GC×GC-TOF MS analysis identified approximately 2000 different VOCs in samples of human breath, many of which have not been previously reported. The 50 VOCs with the highest alveolar gradients (abundance in breath minus abundance in ambient room air) mostly comprised benzene derivatives, acetone, methylated derivatives of alkanes, and isoprene. Conclusions Collection and analysis of breath VOCs with the BCA-GC×GC-TOF MS system extended the size of the detectable human volatile metabolome, the volatome, by an order of magnitude compared to previous reports employing one-dimensional GC-MS. The size of the human volatome has been under-estimated in the past due to coelution of VOCs in one-dimensional GC analytical systems. PMID:24086492

Phillips, Michael; Cataneo, Renee N.; Chaturvedi, Anirudh; Kaplan, Peter D.; Libardoni, Mark; Mundada, Mayur; Patel, Urvish; Zhang, Xiang

2013-01-01

108

Simultaneous determination of 12 ?-agonists in feeds by ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry.  

PubMed

A new analysis method using ultra-performance liquid chromatography (UPLC)-quadrupole-time-of-flight mass spectrometry (Q/TOF MS) was developed for screening and confirmation of 12 ?-agonists in feeds. Under the optimized gradient elution conditions, it takes only 6 min to separate all 12 ?-agonists, and the critical pair of Ractopamine and Isoxsuprine isomers was almost completely separated. Based on the over 10,000 full-width at half maximum (FWHM) mass resolution and high mass accuracy features of TOF MS with 20 mDa mass window, accurate mass chromatograms were reconstructed for individual compounds. The fragmentation pathways of 12 ?-agonists were also studied using Q-TOF MS. The potential of UPLC-Q/TOF MS for confirmatory analysis was shown by determining the accurate mass of all compounds and fragment ions upon collision-induced-dissociation (CID) at different energies. The extra mass measurement errors for all ?-agonists were found to be within 5 ppm. The limits of detection (LODs) and limits of quantitation (LOQs) were determined for all ?-agonists in feeds and found to be 1-5 ng/mL and 5-50 ?g/kg, respectively. The method of UPLC-Q/TOF MS developed in this study was initially applied to the research of feeds for analysis of 12 ?-agonists and proved to be accurate, sensitive, convenient and practical. PMID:23336949

Xiu-Juan, Wang; Feng, Zhang; Fei, Ding; Wei-Qing, Li; Qing-Yu, Chen; Xiao-Gang, Chu; Cheng-Bao, Xu

2013-02-22

109

On-target derivatization of keratan sulfate oligosaccharides with pyrenebutyric acid hydrazide for MALDI-TOF/TOF-MS.  

PubMed

In the present work, a rapid and novel method of on-target plate derivatization of keratan sulfate (KS) oligosaccharides for subsequent analysis by matrix-assisted laser desorption and ionization (MALDI) mass spectrometry is described. MALDI-(time-of-flight)-TOF spectra of labeled KS oligosaccharides revealed that significantly improved ionization can be accomplished through derivatization with pyrenebutyric acid hydrazide (PBH), and the most abundant peak in each spectrum corresponds to the singly charged molecular ion [M - H]- or [M + (n - 1)Na - nH]-, where n = the number of sulfates (n = 1, 2, 3...). The high-energy collision-induced dissociation (heCID) spectra of labeled KS oligosaccharides displayed fragments of compounds similar to those observed with laser-induced dissociation (LID) analysis, suggesting that both heCID and LID fragmentations can be used to analyze KS oligosaccharides. Moreover, fragmentation analysis of all labeled KS oligosaccharides was performed by MALDI-TOF/TOF-MS. With LID mode, sodium adducts showed fragmentation of glycosidic linkages with mainly Y/B/C ions, as well as various cross-ring cleavages providing exact information for the positions of sulfate groups along the KS oligosaccharide chains. This one-step on-target derivatization method makes MALDI-TOF/TOF-MS identification of KS fast, simple and highly throughput for trace amounts of biological samples. PMID:18205237

Zhang, Yuntao; Iwamoto, Takeo; Radke, Gary; Kariya, Yutaka; Suzuki, Kiyoshi; Conrad, Abigail H; Tomich, John M; Conrad, Gary W

2008-06-01

110

Peptidomic analysis of Chinese shrimp ( Fenneropenaeus chinensis) hemolymph by magnetic bead-based MALDI-TOF MS  

NASA Astrophysics Data System (ADS)

Peptides in shrimp hemolymph play an important role in the innate immune response. Analysis of hemolymph will help to detect and identify potential novel biomarkers of microbial infection. We used magnetic bead-based purification (ClinProt system) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) to characterize shrimp hemolymph peptides. Shrimp serum and plasma were used as the source of samples for comparative analysis, and it was found that serum was more suitable for shrimp hemolymph peptidomic analysis. To screen potential specific biomarkers in serum of immune-challenged shrimps, we applied magnetic bead-based MALDI-TOF MS to serum samples from 10 immune-challenged and 10 healthy shrimps. The spectra were analyzed using FlexAnalysis 3.0 and ClinProTools 2.1 software. Thirteen peptide peaks significantly different between the two groups were selected as candidate biomarkers of lipopolysaccharide (LPS)-infection. The diagnostic model established by genetic algorithm using five of these peaks was able to discriminate LPS-challenged shrimps from healthy control shrimps with a sensitivity of 90% and a specificity of 100%. Our approach in MALDITOF MS-based peptidomics is a powerful tool for screening bioactive peptides or biomarkers derived from hemolymph, and will help to enable a better understanding of the innate immune response of shrimps.

Wang, Baojie; Liu, Mei; Jiang, Keyong; Zhang, Guofan; Wang, Lei

2013-03-01

111

Ultra-performance LC-ESI/quadrupole-TOF MS for rapid analysis of chemical constituents of Shaoyao-Gancao decoction.  

PubMed

Shaoyao-Gancao decoction (SGD), a traditional Chinese formulae containing Paeoniae Radix and Glycyrrhizae Radix, is commonly used to relieve abdominal pain. It has attracted increasingly much attention as one of the most popular and valuable herbal medicine in clinic. However, the systematic analysis of chemical constituents of SGD are difficult to determine and thus remain unclear. In this paper, a rapid, sensitive, and reliable ultra-performance LC-ESI/quadrupole-TOF high-definition MS (UPLC-ESI-Q-TOF-MS) with automated MetaboLynx analysis in negative ion mode were established to characterize the chemical constituents of SGD. The analysis was performed on a Waters UPLC(TM) HSS T3 (2.1 × 100 mm, 1.8 ?m) using gradient elution system. MS/MS fragmentation behavior was proposed for aiding the structural identification of the components. With the optimized conditions, a total of 58 peaks were tentatively characterized by comparing the retention time and mass spectrometry data and retrieving the reference literatures. Of note, 44 ingredients were identified from Glycyrrhizae Radix, and 14 were from Paeoniae Radix. It is concluded that a rapid and robust platform based on UPLC-ESI-Q-TOF-MS was successfully developed for globally identifying multiple-constituent of traditional Chinese medicine prescriptions. This is the first report on systematic analysis of chemical constituents and in vivo metabolites of SGD. PMID:23495170

Yin, Quanwei; Wang, Ping; Zhang, Aihua; Sun, Hui; Wu, Xiuhong; Wang, Xijun

2013-04-01

112

Establishing serological classification tree model in rheumatoid arthritis using combination of MALDI-TOF-MS and magnetic beads.  

PubMed

To establish a serological classification tree model for rheumatoid arthritis (RA), protein/peptide profiles of serum were detected by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS) combined with weak cationic exchange (WCX) from Cohort 1, including 65 patients with RA and 41 healthy controls (HC). The samples were randomly divided into a training set and a test set. Twenty-four differentially expressed peaks (P < 0.05) were identified in the training set and 4 of them, namely m/z 3,939, 5,906, 8,146, and 8,569 were chosen to set up our model. This model exhibited a sensitivity of 100.0% and a specificity of 96.0% for differentiating RA patients from HC. The test set reproduced these high levels of sensitivity and specificity, which were 100.0 and 81.2%, respectively. Cohort 2, which include 228 RA patients, was used to further verify the classification efficiency of this model. It came out that 97.4% of them were classified as RA by this model. In conclusion, MALDI-TOF-MS combined with WCX magnetic beads was a powerful method for constructing a classification tree model for RA, and the model we established was useful in recognizing RA. PMID:24292670

Yan, Zhang; Chaojun, Hu; Chuiwen, Deng; Xiaomei, Leng; Xin, Zhang; Yongzhe, Li; Fengchun, Zhang

2015-02-01

113

Intact cell mass spectrometry (ICMS) used to type methicillin-resistant Staphylococcus aureus: media effects and inter-laboratory reproducibility  

Microsoft Academic Search

Intact cell mass spectrometry (ICMS) rapidly analyses the surface composition of microorganisms providing rapid, discriminatory fingerprints for identification and subtyping of important nosocomial pathogens such as methicillin resistant Staphylocccus aureus (MRSA). In this study, ICMS using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI TOF\\/MS) was assessed for the identification and subtyping of MRSA. An intra- and inter-laboratory reproducibility study

J. Walker; A. J. Fox; V. Edwards-Jones; D. B. Gordon

2002-01-01

114

Identification of unknown pesticides in fruits using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Imazalil as a case study of quantification.  

PubMed

Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QqTOF-MS) is an emerging technique offering more rapid and efficient separation, as well as the possibility to obtain accurate mass measurement and tandem mass spectrometry (MS/MS). This paper deals with the use of UPLC-QqTOF-MS to identify the pesticide residues present in complex pear extracts. Carbendazim, imazalil, and ethoxyquin were successfully identified because of the accurate mass determination of their protonated molecule and their major fragments in the product ion mass spectra. A few plastic and latex additives were also found, most of them probably coming from the packaging transfer to the fruits. The potential of the UPLC-QqTOF-MS and UPLC-QqTOF-MS/MS techniques as a quantification tool is also discussed taking imazalil as example. For quantification, calibration curves were linear over a dynamic range of 2 orders of magnitude, whereas higher calibration ranges are better adjusted to polynomial curves of second and third order. Quantification using different mass windows was also assessed. Accurate quantification required mass windows as wide as 20 mDa, narrower mass windows of 5 mDa provided erroneous quantification, probably because the low ion abundance. The mean recoveries and percentage relative standard deviation (RSD) of 35 determinations for imazalil were 76% (13% RSD) by MS and 77% (14% RSD) by MS/MS. The theoretical limit of detection was 0.4 microg kg(-1), with a validated limit of quantification of 2 microg kg(-1). The quantitative data obtained using UPLC-QqTOF-MS were compared with those obtained using conventional liquid chromatography (LC)-MS/MS with a triple quadrupole (QqQ). It was concluded that UPLC-QqTOF-MS might become a powerful analytical tool for both, unknown's identification and quantification of target pesticides. PMID:18021786

Picó, Yolanda; la Farré, Marinel; Soler, Carla; Barceló, Damià

2007-12-28

115

Sensitive high-resolution analysis of biological molecules by capillary zone electrophoresis coupled with reflecting time-of-flight mass spectrometry  

Microsoft Academic Search

Off-line and on-line capillary zone electrophoresis–electrospray ionization time-of-flight mass spectrometry (CZE–ESI-TOF-MS) experiments were conducted using uncoated fused-silica capillaries coupled to a reflecting TOF mass spectrometer via a gold-coated sheathless interface. Off-line and on-line experiments were performed on standard mixtures of proteins and peptides. Samples collected off-line electrokinetically in plastic vials were analyzed by standard ESI–TOF-MS at the pmol level. Sheathless

Mark E. McComb; Andrew N. Krutchinsky; Werner Ens; Kenneth G. Standing; Hélène Perreault

1998-01-01

116

Identification of Arcanobacterium pluranimalium by matrix-assisted laser desorption ionization-time of flight mass spectrometry and, as novel target, by sequencing pluranimaliumlysin encoding gene pla.  

PubMed

In the present study 13 Arcanobacterium pluranimalium strains isolated from various animal origin could successfully be identified phenotypically by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and genotypically by sequencing 16S rDNA and the pluranimaliumlysin encoding gene pla. The detection of mass spectra by MALDI-TOF MS and the novel genotypic approach using gene pla might help to identify A. pluranimalium in future and might elucidate the role this species plays in infections of animals. PMID:24345409

Balbutskaya, A; Sammra, O; Nagib, S; Hijazin, M; Alber, J; Lämmler, C; Foster, G; Erhard, M; Wragg, P N; Abdulmawjood, A; Prenger-Berninghoff, E

2014-01-31

117

Diversity of Clonostachys species assessed by molecular phylogenetics and MALDI-TOF mass spectrometry.  

PubMed

We assessed the species diversity among 45 strains of Clonostachys from different substrates and localities in Brazil using molecular phylogenetics, and compared the results with the phenotypic classification of strains obtained from matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Phylogenetic analyses were based on beta tubulin (Tub), ITS-LSU rDNA, and a combined Tub-ITS DNA dataset. MALDI-TOF MS analyses were performed using intact conidia and conidiophores of strains cultivated on oatmeal agar and 4% malt extract agar. Six known species were identified: Clonostachys byssicola, Clonostachys candelabrum, Clonostachys pseudochroleuca, Clonostachys rhizophaga, Clonostachys rogersoniana, and Clonostachys rosea. Two clades and two singleton lineages did not correspond to known species represented in the reference DNA dataset and were identified as Clonostachys sp. 1-4. Multivariate cluster analyses of MALDI-TOF MS data classified the strains into eight clusters and three singletons, corresponding to the ten identified species plus one additional cluster containing two strains of C. rogersoniana that split from the other co-specific strains. The consistent results of MALDI-TOF MS supported the identification of strains assigned to C. byssicola and C. pseudochroleuca, which did not form well supported clades in all phylogenetic analyses, but formed distinct clusters in the MALDI-TOF dendrograms. PMID:25457948

Abreu, Lucas M; Moreira, Gláucia M; Ferreira, Douglas; Rodrigues-Filho, Edson; Pfenning, Ludwig H

2014-12-01

118

MALDI-TOF mass spectrometry proteomic based identification of clinical bacterial isolates  

PubMed Central

Background & objectives: Pathogenic bacteria often cause life threatening infections especially in immunocompromised individuals. Therefore, rapid and reliable species identification is essential for a successful treatment and disease management. We evaluated a rapid, proteomic based technique for identification of clinical bacterial isolates by protein profiling using matrix-assisted laser desorption-ionization time - of - flight mass spectrometry (MALDI-TOF MS). Methods: Freshly grown bacterial isolates were selected from culture plates. Ethanol/formic acid extraction procedure was carried out, followed by charging of MALDI target plate with the extract and overlaying with ?-cyano-4 hydroxy-cinnamic acid matrix solution. Identification was performed using the MALDI BioTyper 1.1, software for microbial identification (Bruker Daltonik GmbH, Bremen, Germany). Results: A comparative analysis of 82 clinical bacterial isolates using MALDI -TOF MS and conventional techniques was carried out. Amongst the clinical isolates, the accuracy at the species level for clinical isolates was 98.78%. One out of 82 isolates was not in accordance with the conventional assays because MALDI-TOF MS established it as Streptococcus pneumoniae and conventional methods as Streptococcus viridans. Interpretation & conclusions: MALDI - TOF MS was found to be an accurate, rapid, cost-effective and robust system for identification of clinical bacterial isolates. This innovative approach holds promise for earlier therapeutic intervention leading to better patient care. PMID:25758576

Panda, Ashutosh; Kurapati, Sravya; Samantaray, Jyotish C.; Srinivasan, Alagiri; Khalil, Shehla

2014-01-01

119

Mass spectrometry  

Microsoft Academic Search

A review of mass spectrometry in organic chemistry is given, dealing with advances in instrumentation and computer techniques, selected topics in gas-phase ion chemistry, and applications in such fields as biomedicine, natural-product studies, and environmental pollution analysis. Innovative techniques and instrumentation are discussed, along with chromatographic-mass spectrometric on-line computer techniques, mass spectral interpretation and management techniques, and such topics in

A. L. Burlingame; Cedric H. L. Shackleton; Ian. Howe; O. S. Chizhov

1978-01-01

120

UPLC-TOF-MS Characterization and Identification of Bioactive Iridoids in Cornus mas Fruit.  

PubMed

Cornus mas L. is indigenous to Europe and parts of Asia. Although Cornus is widely considered to be an iridoid rich genera, only two iridoids have been previously found in this plant. The lack of information on taxonomically and biologically active iridoids prompted us to develop and optimize an analytical method for characterization of additional phytochemicals in C. mas fruit. An ultra performance liquid chromatography (UPLC) coupled with photodiode array spectrophotometry (PDA) and electrospray time-of-flight mass spectrometry (ESI-TOF-MS) was employed and mass parameters were optimized. Identification was made by elucidating the mass spectral data and further confirmed by comparing retention times and UV spectra of target peaks with those of reference compounds. Primary DNA damage and antigenotoxicity tests in E. coli PQ37 were used to screen the iridoids for biological activity. As a result, ten phytochemicals were identified, including iridoids loganic acid, loganin, sweroside, and cornuside. Nine of these were reported for the first time from C. mas fruit. The iridoids did not induce SOS repair of DNA, indicating a lack of genotoxic activity in E. coli PQ37. However, loganin, sweroside, and cornuside did reduce the amount of DNA damage caused by 4-nitroquinoline 1-oxide, suggesting potential antigenotoxic activity. PMID:24228188

Deng, Shixin; West, Brett J; Jensen, C Jarakae

2013-01-01

121

Evaluation of automated direct sample introduction with comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry for the screening analysis of dioxins of fish oil  

Technology Transfer Automated Retrieval System (TEKTRAN)

An automated direct sample introduction technique coupled to comprehensive two-dimensional gas chromatography-time of flight mass spectrometry (DSI-GC×GC/TOF-MS) was applied for the development of a relatively fast and easy analytical screening method for 17 polychlorinated dibenzo-p-dioxins/dibenzo...

122

Rapid Identification of Cryptococcus neoformans and Cryptococcus gattii by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry ?  

PubMed Central

Compared to DNA sequence analysis, matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) correctly identified 100% of Cryptococcus species, distinguishing the notable pathogens Cryptococcus neoformans and C. gattii. Identification was greatly enhanced by supplementing a commercial spectral library with additional entries to account for subspecies variability. PMID:21653762

McTaggart, Lisa R.; Lei, Eric; Richardson, Susan E.; Hoang, Linda; Fothergill, Annette; Zhang, Sean X.

2011-01-01

123

Comparison of PCR/Electron spray Ionization-Time-of-Flight-Mass Spectrometry versus Traditional Clinical Microbiology for active surveillance of organisms contaminating high-use surfaces in a burn intensive care unit, an orthopedic ward and healthcare workers  

PubMed Central

Background Understanding nosocomial pathogen transmission is restricted by culture limitations. Novel platforms, such as PCR-based electron spray ionization-time-of-flight-mass spectrometry (ESI-TOF-MS), may be useful as investigational tools. Methods Traditional clinical microbiology (TCM) and PCR/ESI-TOF-MS were used to recover and detect microorganisms from the hands and personal protective equipment of 10 burn intensive care unit (ICU) healthcare workers providing clinical care at a tertiary care military referral hospital. High-use environmental surfaces were assessed in 9 burn ICU and 10 orthopedic patient rooms. Clinical cultures during the study period were reviewed for pathogen comparison with investigational molecular diagnostic methods. Results From 158 samples, 142 organisms were identified by TCM and 718 by PCR/ESI-TOF-MS. The molecular diagnostic method detected more organisms (4.5?±?2.1 vs. 0.9?±?0.8, p?TOF-MS. Gram-negative organisms were less commonly identified than gram-positive by both methods; especially by TCM. Among all detected bacterial species, similar percentages were typical nosocomial pathogens (18-19%) for TCM vs. PCR/ESI-TOF-MS. PCR/ESI-TOF-MS also detected mecA in 112 samples, vanA in 13, and KPC-3 in 2. MecA was associated (p?TOF-MS detected more organisms, especially gram-negatives, compared to TCM, but the current assay format is limited by the number of antibiotic resistance determinants it covers. Further large-scale assessments of PCR/ESI-TOF-MS for hospital surveillance are warranted. PMID:23050585

2012-01-01

124

Simultaneous Determination of Ferulic Acid and Phthalides of Angelica Sinensis Based on UPLC-Q-TOF/MS.  

PubMed

The radix of Angelica sinensis (AS) is one of the most commonly used as a herbal medicine. To investigate the geoherbalism and quality evaluation of AS, an ultra performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF/MS) method was established to analyze and identify ferulic acid and phthalides in AS. The results showed that among samples collected in four regions, the relative contents of ferulic acid and phthalides were highest in samples collected in Gansu, and the samples from the four different regions were apparently classified into four groups. Meanwhile, the relative content in non-fumigated root was higher than after sulfur-fumigation and the sulfur-fumigated and non-fumigated samples were obviously divided into two groups by PCA. The paper establishes a systematic and objective evaluation system to provide a scientific basis for evaluating the quality of AS. PMID:25781070

Wei, Wen-Long; Huang, Lin-Fang

2015-01-01

125

HPLC-Q-TOF-MS identification of antioxidant and antihypertensive peptides recovered from cherry (Prunus cerasus L.) subproducts.  

PubMed

The processing of fruits, such as cherries, is characterized by generating a lot of waste material such as fruit stones, skins, etc. To contribute to environmental sustainability, it is necessary to recover these residues. Cherry stones contain seeds with a significant amount of proteins that are underused and undervalued. The aim of this work was to extract cherry seed proteins, to evaluate the presence of bioactive peptides, and to identify them by mass spectrometry. The digestion of cherry seed proteins was optimized, and three different enzymes were employed: Alcalase, Thermolysin, and Flavourzyme. Peptide extracts obtained by the digestion of the cherry seed protein isolate with Alcalase and Thermolysin yielded the highest antioxidant and antihypertensive capacities. Ultrafiltration of hydrolysates allowed obtaining fractions with high antioxidant and antihypertensive capabilities. HPLC-Q-TOF-MS together with bioinformatics tools enabled one to identify peptides in these fractions. PMID:25599260

García, María Concepción; Endermann, Jochan; González-García, Estefanía; Marina, María Luisa

2015-02-11

126

Identification of Rare Pathogenic Bacteria in a Clinical Microbiology Laboratory: Impact of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry  

PubMed Central

During the past 5 years, matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry (MS) has become a powerful tool for routine identification in many clinical laboratories. We analyzed our 11-year experience in routine identification of clinical isolates (40 months using MALDI-TOF MS and 91 months using conventional phenotypic identification [CPI]). Among the 286,842 clonal isolates, 284,899 isolates of 459 species were identified. The remaining 1,951 isolates were misidentified and required confirmation using a second phenotypic identification for 670 isolates and using a molecular technique for 1,273 isolates of 339 species. MALDI-TOF MS annually identified 112 species, i.e., 36 species/10,000 isolates, compared to 44 species, i.e., 19 species/10,000 isolates, for CPI. Only 50 isolates required second phenotypic identifications during the MALDI-TOF MS period (i.e., 4.5 reidentifications/10,000 isolates) compared with 620 isolates during the CPI period (i.e., 35.2/10,000 isolates). We identified 128 bacterial species rarely reported as human pathogens, including 48 using phenotypic techniques (22 using CPI and 37 using MALDI-TOF MS). Another 75 rare species were identified using molecular methods. MALDI-TOF MS reduced the time required for identification by 55-fold and 169-fold and the cost by 5-fold and 96-fold compared with CPI and gene sequencing, respectively. MALDI-TOF MS was a powerful tool not only for routine bacterial identification but also for identification of rare bacterial species implicated in human infectious diseases. The ability to rapidly identify bacterial species rarely described as pathogens in specific clinical specimens will help us to study the clinical burden resulting from the emergence of these species as human pathogens, and MALDI-TOF MS may be considered an alternative to molecular methods in clinical laboratories. PMID:23637301

Seng, Piseth; Abat, Cedric; Rolain, Jean Marc; Colson, Philippe; Lagier, Jean-Christophe; Gouriet, Frédérique; Fournier, Pierre Edouard; Drancourt, Michel; La Scola, Bernard

2013-01-01

127

Comprehensive two-dimensional gas chromatography\\/time-of-flight mass spectrometry peak sorting algorithm  

Microsoft Academic Search

We report a novel peak sorting method for the two-dimensional gas chromatography\\/time-of-flight mass spectrometry (GC×GC\\/TOF-MS) system. The objective of peak sorting is to recognize peaks from the same metabolite occurring in different samples from thousands of peaks detected in the analytical procedure. The developed algorithm is based on the fact that the chromatographic peaks for a given analyte have similar

Cheolhwan Oh; Xiaodong Huang; Fred E. Regnier; Charles Buck; Xiang Zhang

2008-01-01

128

Identification of Gallibacterium species by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry evaluated by multilocus sequence analysis.  

PubMed

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) whole-cell fingerprinting was used for characterization of 66 reference strains of Gallibacterium. The 4 recognised Gallibacterium species and Gallibacterium genomospecies 1 yielded reproducible and unique mass spectrum profiles, which were confirmed with Bruker Biotyper reference database version 3. The reproducibility of MALDI-TOF MS results were evaluated varying the age and storage of the cultures investigated. Reliable species identification was possible for up to 8 days of storage at 4°C and less reliable if the bacteria were stored at room temperature (20°C). However, if the strains were grown longer than 48h at 37°C under microaerobic atmosphere, poor identification results were obtained, due to changes in protein profile. The MALDI-TOF MS results of all 66 strains demonstrated 87.9% concordance with results based upon biochemical/physiological characterization. In addition, diversities outlined by MALDI-TOF MS were verified by sequencing the rpoB (n=43), 16S rRNA (n=28), infB (n=14), and recN (n=14) genes (multilocus sequence analysis, MLSA). In addition, discrepancies were observed between some of the genes sequenced. Results obtained demonstrated that MALDI-TOF MS fingerprinting represents a fast and reliable method for identification and differentiation of the 4 recognised Gallibacterium species and possible a fifth species Gallibacterium genomospecies 1, with applications in clinical diagnostics. PMID:21596619

Alispahic, Merima; Christensen, Henrik; Hess, Claudia; Razzazi-Fazeli, Ebrahim; Bisgaard, Magne; Hess, Michael

2011-08-01

129

Fragmentation patterns study of iridoid glycosides in Fructus Gardeniae by HPLC-Q/TOF-MS/MS.  

PubMed

Iridoid glycosides (IGs), the major constituents in Fructus Gardeniae, have demonstrated various pharmacological activities, but there is no systematic chemical profile of IGs in Fructus Gardeniae in the published literature until now. Therefore, it is imperative that a rapid and sensitive high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (HPLC-Q/TOF-MS/MS) method is established for comprehensive characterization of IGs in Fructus Gardeniae. Firstly, the fragmentation patterns of six known IGs were investigated and proposed and further concluded the diagnostic fragment ions and characteristic fragmentation pathways. Then, based on the summarized fragmentation patterns and the known compounds in the literatures, the other IGs in Fructus Gardeniae were identified successively. As a result, a total of 20 IGs were identified, of which three pairs of epimers were structurally characterized and differentiated. More importantly, one compound, the isoshanzhiside methyl ester, was tentatively identified as a new compound. The results of this study demonstrate the superiority of HPLC-MS with a high-resolution mass spectrometer for the rapid and sensitive structural elucidation of the multiple groups of constituents in Fructus Gardeniae. PMID:24782425

Fu, Zhiwen; Xue, Rui; Li, Zhixiong; Chen, Mingcang; Sun, Zhaolin; Hu, Yiyang; Huang, Chenggang

2014-12-01

130

Quantification of proteins on gold nanoparticles by combining MALDI-TOF MS and proteolysis  

NASA Astrophysics Data System (ADS)

Protein-coated nanoparticles have been used in many studies, including those related to drug delivery, disease diagnosis, therapeutics, and bioassays. The number and density of proteins on the particles’ surface are important parameters that need to be calculable in most applications. While quantification methods for two-dimensional surface-bound proteins are commonly found, only a few methods for the quantification of proteins on three-dimensional surfaces such as nanoparticles have been reported. In this paper, we report on a new method of quantifying proteins on nanoparticles using matrix assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry (MS). In this method, the nanoparticle-bound proteins are digested by trypsin and the resulting peptide fragments are analyzed by MALDI-TOF MS after the addition of an isotope-labeled internal standard (IS) which has the same sequence as a reference peptide of the surface-bound protein. Comparing the mass intensities between the reference peptide and the IS allows the absolute quantification of proteins on nanoparticles, because they have the same molecular milieu. As a model system, gold nanoparticles were examined using bovine serum albumin (BSA) as a coating protein. We believe that our strategy will be a useful tool that can provide researchers with quantitative information about the proteins on surfaces of three-dimensional materials.

Ju, Soomi; Yeo, Woon-Seok

2012-04-01

131

Species Identification of Clinical Isolates of Anaerobic Bacteria: a Comparison of Two Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Systems ?  

PubMed Central

We compared two matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) systems (Shimadzu/SARAMIS and Bruker) on a collection of consecutive clinically important anaerobic bacteria (n = 290). The Bruker system had more correct identifications to the species level (67.2% versus 49.0%), but also more incorrect identifications (7.9% versus 1.4%). The system databases need to be optimized to increase identification levels. However, MALDI-TOF MS in its present version seems to be a fast and inexpensive method for identification of most clinically important anaerobic bacteria. PMID:21998433

Justesen, Ulrik Stenz; Holm, Anette; Knudsen, Elisa; Andersen, Line Bisgaard; Jensen, Thøger Gorm; Kemp, Michael; Skov, Marianne Nielsine; Gahrn-Hansen, Bente; Møller, Jens Kjølseth

2011-01-01

132

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry: revolutionizing clinical laboratory diagnosis of mould infections.  

PubMed

The clinical diagnosis of mould infections currently involves complex species identification based on morphological criteria, which is often prone to error. Employing an extensive mould species reference spectral library (up to 2832 reference spectra, corresponding to 708 strains from 347 species), we assessed the extent to which matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) enhanced the accuracy of species identification. MALDI-TOF MS data were validated against morphology-based and DNA sequence-based results with 262 clinical isolates collected over a 4-month period in 2013. The implementation of MALDI-TOF MS resulted in a dramatic improvement in mould identification at the species level (from 78.2% to 98.1%) and a marked reduction in the misidentification rate (from 9.8% to 1.2%). We then compared the mould identification results obtained before (i.e. 2011) and after (i.e. 2013) the implementation of MALDI-TOF MS in routine identification procedures, which showed an improvement from 64.57% to 100%. Reassessment of a set of isolates from 2011 with this procedure, including MALDI-TOF MS, yielded an increase in species diversity from 16 to 42 species. Finally, application of this procedure during a 16-month period (2012-2013) enabled the identification of 1094 of 1107 (98.8%) clinical mould isolates corresponding to 107 distinct species. MALDI-TOF MS-based mould species identification may soon challenge traditional techniques in the clinical laboratory, as patient prognosis is largely contingent on rapid and accurate diagnosis. PMID:24995483

Gautier, M; Ranque, S; Normand, A-C; Becker, P; Packeu, A; Cassagne, C; L'Ollivier, C; Hendrickx, M; Piarroux, R

2014-12-01

133

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: a Fundamental Shift in the Routine Practice of Clinical Microbiology  

PubMed Central

SUMMARY Within the past decade, clinical microbiology laboratories experienced revolutionary changes in the way in which microorganisms are identified, moving away from slow, traditional microbial identification algorithms toward rapid molecular methods and mass spectrometry (MS). Historically, MS was clinically utilized as a high-complexity method adapted for protein-centered analysis of samples in chemistry and hematology laboratories. Today, matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) MS is adapted for use in microbiology laboratories, where it serves as a paradigm-shifting, rapid, and robust method for accurate microbial identification. Multiple instrument platforms, marketed by well-established manufacturers, are beginning to displace automated phenotypic identification instruments and in some cases genetic sequence-based identification practices. This review summarizes the current position of MALDI-TOF MS in clinical research and in diagnostic clinical microbiology laboratories and serves as a primer to examine the “nuts and bolts” of MALDI-TOF MS, highlighting research associated with sample preparation, spectral analysis, and accuracy. Currently available MALDI-TOF MS hardware and software platforms that support the use of MALDI-TOF with direct and precultured specimens and integration of the technology into the laboratory workflow are also discussed. Finally, this review closes with a prospective view of the future of MALDI-TOF MS in the clinical microbiology laboratory to accelerate diagnosis and microbial identification to improve patient care. PMID:23824373

Clark, Andrew E.; Kaleta, Erin J.; Arora, Amit

2013-01-01

134

The utility of nonspecific proteases in the characterization of glycoproteins by high-resolution time-of-flight mass spectrometry  

Microsoft Academic Search

Degradation of glycoproteins with the nonspecific protease pronase was examined by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS). High mass resolution (in excess of 10 000 at FWHM) and mass accuracy on monoisotopic species (better than 10 ppm) obtained with the combination of delayed extraction and the reflector mode of analysis enabled the successful interpretation of very complex mixtures resulting

Peter Juhasz; Stephen A. Martin

1997-01-01

135

Acoustic trapping for bacteria identification in positive blood cultures with MALDI-TOF MS.  

PubMed

Matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently changing the clinical routine for identification of microbial pathogens. One important application is the rapid identification of bacteria for the diagnosis of bloodstream infections (BSI). A novel approach based on acoustic trapping and an integrated selective enrichment target (ISET) microchip that improves the sample preparation step for this type of analysis is presented. The method is evaluated on clinically relevant samples in the form of Escherichia coli infected blood cultures. It is shown that noncontact acoustic trapping enables capture, enrichment, and washing of bacteria directly from the complex background of crude blood cultures. The technology replaces centrifugation-based separation with a faster and highly automated sample preparation method that minimizes manual handling of hazardous pathogens. The presented method includes a solid phase extraction step that was optimized for enrichment of the bacterial proteins and peptides that are used for bacterial identification. The acoustic trapping-based assay provided correct identification in 12 out 12 cases of E. coli positive blood cultures with an average score of 2.19 ± 0.09 compared to 1.98 ± 0.08 when using the standard assay. This new technology opens up the possibility to automate and speed up an important and widely used diagnostic assay for bloodstream infections. PMID:25269087

Hammarström, Björn; Nilson, Bo; Laurell, Thomas; Nilsson, Johan; Ekström, Simon

2014-11-01

136

Peptide peak intensities enhanced by cysteine modifiers and MALDI TOF MS.  

PubMed

Two cysteine-specific modifiers we reported previously, N-ethyl maleimide (NEM) and iodoacetanilide (IAA), have been applied to the labeling of cysteine residues of peptides for the purpose of examining the enhancement of ionization efficiencies in combination with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS). The peak intensities of the peptides as a result of modification with these modifiers were compared with the peak intensities of peptides modified with a commercially available cysteine-specific modifier, iodoacetamide (IA). Our experiments show significant enhancement in the peak intensities of three cysteine-containing synthetic peptides modified with IAA compared to those modified with IA. The results showed a 4.5-6-fold increase as a result of modification with IAA compared to modification with IA. Furthermore, it was found that IAA modification also significantly enhanced the peak intensities of many peptides of a commercially available proteins, bovine serum albumin (BSA), compared to those modified with IA. This significant enhancement helped identify a greater number of peptides of these proteins, leading to a higher sequence coverage with greater confidence scores in identification of proteins with the use of IAA. PMID:23280742

Zabet-Moghaddam, Masoud; Shaikh, Aarif L; Niwayama, Satomi

2012-12-01

137

Identification of astilbin metabolites produced by human intestinal bacteria using UPLC-Q-TOF/MS.  

PubMed

Astilbin, mainly isolated from a commonly used herbal medicine, Smilax glabra Roxb (SGR), exhibits a variety of pharmacological activities and biological effects. It is metabolized by intestinal bacteria after oral administration which leads to the variation of ethnopharmacological profile of this traditional medicine. However, little is known on the interactions of this active compound with intestinal bacteria, which would be very helpful in unravelling how SGR works. In this study, different pure bacteria from human feces were isolated and were used to investigate their conversion capability of astilbin. Ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MS) technique combined with Metabolynx(TM) software was used to analyze astilbin and its metabolites. The parent compound and two metabolites (quercetin and eriodictyol) were detected in the isolated bacterial samples compared with blank samples. Quercetin was present in Enterococcus sp. 8B, 8-2 and 9-2 samples. Eriodictyol was only identified in Enterococcus sp. 8B sample. The metabolic routes and metabolites of astilbin produced by the different intestinal bacteria are reported for the first time. This will be useful for the investigation of the pharmacokinetic study of astilbin in vivo and the role of different intestinal bacteria in the metabolism of natural compounds. PMID:24399635

Zhao, Min; Xu, Jun; Qian, Dawei; Guo, Jianming; Jiang, Shu; Shang, Er-xin; Duan, Jin-ao

2014-07-01

138

Potential Pitfalls in MALDI-TOF MS Analysis of Abiotically Synthesized RNA Oligonucleotides  

NASA Astrophysics Data System (ADS)

Demonstration of the abiotic polymerization of ribonucleotides under conditions consistent with conditions that may have existed on the prebiotic Earth is an important goal in "RNA world" research. Recent reports of abiotic RNA polymerization with and without catalysis rely on techniques such as HPLC, gel electrophoresis, and MALDI-TOF MS to analyze the reaction products. It is essential to understand the limitations of these techniques in order to accurately interpret the results of these analyses. In particular, techniques that rely on mass for peak identification may not be able to distinguish between a single, linear RNA oligomer and stable aggregates of smaller linear and/or cyclic RNA molecules. In the case of MALDI-TOF MS, additional complications may arise from formation of salt adducts and MALDI matrix complexes. This is especially true for abiotic RNA polymerization reactions because the concentration of longer RNA chains can be quite low and RNA, as a polyelectrolyte, is highly susceptible to adduct formation and aggregation. Here we focus on MALDI-TOF MS analysis of abiotic polymerization products of imidazole-activated AMP in the presence and absence of montmorillonite clay as a catalyst. A low molecular weight oligonucleotide standard designed for use in MALDI-TOF MS and a 3'-5' polyadenosine monophosphate reference standard were also run for comparison and calibration. Clay-catalyzed reaction products of activated GMP and UMP were also examined. The results illustrate the ambiguities associated with assignment of m/z values in MALDI mass spectra and the need for accurate calibration of mass spectra and careful sample preparation to minimize the formation of adducts and other complications arising from the MALDI process.

Burcar, Bradley T.; Cassidy, Lauren M.; Moriarty, Elizabeth M.; Joshi, Prakash C.; Coari, Kristin M.; McGown, Linda B.

2013-06-01

139

Direct determination of pregabalin in human urine by nonaqueous CE-TOF-MS.  

PubMed

Determination of pregabalin in urine samples was carried out by nonaqueous CE with TOF-MS via ESI, with a mixture of 10 mM ammonium formate and 0.05% acetic acid in methanol. By using TOF-MS, accurate mass information was obtained, thus causing a great improvement in qualitative ability. In order to avoid ionic suppression, urine samples dilution 1:10 was used. This was the only treatment to urine samples before the injection. Despite this dilution, the detection limit was as low as 0.03 ?g/mL for pregabalin. The method was validated with respect to accuracy, precision, and linearity, LOD, and LOQ. This method was applied to the analysis of urine samples from seven different cancer patients undergoing treatment with pregabalin. The developed method may find wide application for the routine determination of pregabalin in biological samples in order to establish a more efficient and safe dosage. PMID:23463484

Rodríguez, Juana; Castañeda, Gregorio; Muñoz, Lorena

2013-05-01

140

The Construction and Evaluation of Reference Spectra for the Identification of Human Pathogenic Microorganisms by MALDI-TOF MS  

PubMed Central

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is an emerging technique for the rapid and high-throughput identification of microorganisms. There remains a dearth of studies in which a large number of pathogenic microorganisms from a particular country or region are utilized for systematic analyses. In this study, peptide mass reference spectra (PMRS) were constructed and evaluated from numerous human pathogens (a total of 1019 strains from 94 species), including enteric (46 species), respiratory (21 species), zoonotic (17 species), and nosocomial pathogens (10 species), using a MALDI-TOF MS Biotyper system (MBS). The PMRS for 380 strains of 52 species were new contributions to the original reference database (ORD). Compared with the ORD, the new reference database (NRD) allowed for 28.2% (from 71.5% to 99.7%) and 42.3% (from 51.3% to 93.6%) improvements in identification at the genus and species levels, respectively. Misidentification rates were 91.7% and 57.1% lower with the NRD than with the ORD for genus and species identification, respectively. Eight genera and 25 species were misidentified. For genera and species that are challenging to accurately identify, identification results must be manually determined and adjusted in accordance with the database parameters. Through augmentation, the MBS demonstrated a high identification accuracy and specificity for human pathogenic microorganisms. This study sought to provide theoretical guidance for using PMRS databases in various fields, such as clinical diagnosis and treatment, disease control, quality assurance, and food safety inspection. PMID:25181391

Xiao, Di; Ye, Changyun; Zhang, Huifang; Kan, Biao; Lu, Jingxing; Xu, Jianguo; Jiang, Xiugao; Zhao, Fei; You, Yuanhai; Yan, Xiaomei; Wang, Duochun; Hu, Yuan; Zhang, Maojun; Zhang, Jianzhong

2014-01-01

141

Single-crystalline EuF3 hollow hexagonal microdisks: synthesis and application as a background-free matrix for MALDI-TOF-MS analysis of small molecules and polyethylene glycols.  

PubMed

Single-crystalline EuF(3) hexagonal microdisks with hollow interior were fabricated to serve as a background-free matrix for analysis of small molecules and polyethylene glycols (PEGs) by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The long-lived excited state of europium ions can transfer energy to high-energy vibrations of organic molecules, which provides the potential technological application in MALDI-TOF-MS analysis of small molecules and PEGs. The efficiency of the hollow microdisks as a novel matrix of low molecular weight compounds was verified by analysis of small peptide, amino acid, organic compounds, and hydroxypropyl beta-cyclodextrin (HP-beta-CD). The advantage of this matrix in comparison with alpha-cyano-4-hydroxycinnamic acid (CHCA) and 2,5-dihydroxybenzoic acid (DHB) was demonstrated by MALDI-TOF-MS analysis of an amino acid mixture and a peptide mixture. This matrix is successfully used for analysis of PEGs (PEG 2000, PEG 4000, PEG 8000, PEG 15000, and PEG 30000), suggesting a potential for monitoring reactions and for synthetic polymer quality control. The upper limit of detectable mass range was approximately 35,000 Da (PEG 30000). It is believed that this work will not only offer a new technique for high-speed analysis of small molecules and PEGs but also open a new field for applications of rare earth fluorides. PMID:19681619

Chen, Zhiming; Geng, Zhirong; Shao, Dalin; Mei, Yuhua; Wang, Zhilin

2009-09-15

142

Classification of the genus Bacillus based on MALDI-TOF MS analysis of ribosomal proteins coded in S10 and spc operons.  

PubMed

A rapid bacterial identification method by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) using ribosomal proteins coded in S10 and spc operons as biomarkers, named the S10-GERMS (the S10-spc-alpha operon gene encoded ribosomal protein mass spectrum) method, was applied for the genus Bacillus a Gram-positive bacterium. The S10-GERMS method could successfully distinguish the difference between B. subtilis subsp. subtilis NBRC 13719(T) and B. subtilis subsp. spizizenii NBRC 101239(T) because of the mass difference of 2 ribosomal subunit proteins, despite the difference of only 2 bases in the 16S rRNA gene between them. The 8 selected reliable and reproducible ribosomal subunit proteins without disturbance of S/N level on MALDI-TOF MS analysis, S10, S14, S19, L18, L22, L24, L29, and L30, coded in S10 and spc operons were significantly useful biomarkers for rapid bacterial classification at species and strain levels by the S10-GERMS method of genus Bacillus strains without purification of ribosomal proteins. PMID:21469741

Hotta, Yudai; Sato, Jun; Sato, Hiroaki; Hosoda, Akifumi; Tamura, Hiroto

2011-05-25

143

UPLC/Q-TOF MS-Based Metabolomics and qRT-PCR in Enzyme Gene Screening with Key Role in Triterpenoid Saponin Biosynthesis of Polygala tenuifolia  

PubMed Central

Background The dried root of Polygala tenuifolia, named Radix Polygalae, is a well-known traditional Chinese medicine. Triterpenoid saponins are some of the most important components of Radix Polygalae extracts and are widely studied because of their valuable pharmacological properties. However, the relationship between gene expression and triterpenoid saponin biosynthesis in P. tenuifolia is unclear. Methodology/Findings In this study, ultra-performance liquid chromatography (UPLC) coupled with quadrupole time-of-flight mass spectrometry (Q-TOF MS)-based metabolomic analysis was performed to identify and quantify the different chemical constituents of the roots, stems, leaves, and seeds of P. tenuifolia. A total of 22 marker compounds (VIP>1) were explored, and significant differences in all 7 triterpenoid saponins among the different tissues were found. We also observed an efficient reference gene GAPDH for different tissues in this plant and determined the expression level of some genes in the triterpenoid saponin biosynthetic pathway. Results showed that MVA pathway has more important functions in the triterpenoid saponin biosynthesis of P. tenuifolia. The expression levels of squalene synthase (SQS), squalene monooxygenase (SQE), and beta-amyrin synthase (?-AS) were highly correlated with the peak area intensity of triterpenoid saponins compared with data from UPLC/Q-TOF MS-based metabolomic analysis. Conclusions/Significance This finding suggested that a combination of UPLC/Q-TOF MS-based metabolomics and gene expression analysis can effectively elucidate the mechanism of triterpenoid saponin biosynthesis and can provide useful information on gene discovery. These findings can serve as a reference for using the overexpression of genes encoding for SQS, SQE, and/or ?-AS to increase the triterpenoid saponin production of P. tenuifolia. PMID:25148032

Li, Zhenyu; Xu, Xiaoshuang; Peng, Bing; Qin, Xuemei; Du, Guanhua

2014-01-01

144

Label-free detection and identification of protein ligands captured by receptors in a polymerized planar lipid bilayer using MALDI-TOF MS.  

PubMed

Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) coupled with affinity capture is a well-established method to extract biological analytes from complex samples followed by label-free detection and identification. Many bioanalytes of interest bind to membrane-associated receptors; however, the matrices and high-vacuum conditions inherent to MALDI-TOF MS make it largely incompatible with the use of artificial lipid membranes with incorporated receptors as platforms for detection of captured proteins and peptides. Here we show that cross-linking polymerization of a planar supported lipid bilayer (PSLB) provides the stability needed for MALDI-TOF MS analysis of proteins captured by receptors embedded in the membrane. PSLBs composed of poly(bis-sorbylphosphatidylcholine) (poly(bis-SorbPC)) and doped with the ganglioside receptors GM1 and GD1a were used for affinity capture of the B subunits of cholera toxin, heat-labile enterotoxin, and pertussis toxin. The three toxins were captured simultaneously, then detected and identified by MS on the basis of differences in their molecular weights. Poly(bis-SorbPC) PSLBs are inherently resistant to nonspecific protein adsorption, which allowed selective toxin detection to be achieved in complex matrices (bovine serum and shrimp extract). Using GM1-cholera toxin subunit B as a model receptor-ligand pair, we estimated the minimal detectable concentration of toxin to be 4 nM. On-plate tryptic digestion of bound cholera toxin subunit B followed by MS/MS analysis of digested peptides was performed successfully, demonstrating the feasibility of using the PSLB-based affinity capture platform for identification of unknown, membrane-associated proteins. Overall, this work demonstrates that combining a poly(lipid) affinity capture platform with MALDI-TOF MS detection is a viable approach for capture and proteomic characterization of membrane-associated proteins in a label-free manner. PMID:25694144

Liang, Boying; Ju, Yue; Joubert, James R; Kaleta, Erin J; Lopez, Rodrigo; Jones, Ian W; Hall, Henry K; Ratnayaka, Saliya N; Wysocki, Vicki H; Saavedra, S Scott

2015-04-01

145

Chemical derivatization combined with capillary LC or MALDI-TOF MS for trace determination of lipoic acid in cosmetics and integrated protein expression profiling in human keratinocytes.  

PubMed

Lipoic acid (LA) is an essential cofactor in mitochondrial enzymes and an ideal antioxidant in prokaryotic and eukaryotic cells. Capillary liquid chromatography coupled with ultraviolet detection (CapLC-UV) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) are two environmentally friendly methods for determining LA. In this study, a pre-column microwave-assisted derivatization with 4-bromomethyl-6,7-dimethoxycoumarin enhanced the UV absorbance of LA and was monitored at 345 nm by CapLC-UV. Gradient separation was performed using a reversed-phase C18 column with a mobile phase consisting of acetonitrile-0.1% formic acid solution. The ionization of LA was increased, and the LA derivative was detected by MALDI-TOF MS at m/z 683 with an ?-cyano-4-hydroxycinnamic acid matrix. The linear response ranged from 0.1 to 40 ?M with a correlation coefficient of 0.999. The CapLC-UV and MALDI-TOF MS had detection limits of 5 and 4 fmol, respectively. These methods effectively detected LA in dietary supplements and cosmetics. Cellular proteomes of a human keratinocyte cell line (HaCaT) irradiated with UV radiation were also compared with and without LA treatment. The cellular proteomes were identified by nanoultra performance LC with LTQ Orbitrap system after trypsin digestion. Protein identification was performed by simultaneous peptide sequencing and MASCOT search. The analysis revealed changes in several proteins, including CDC42, TPI1, HNRPA2B1, PRDX1, PTGES3 and MYL6. PMID:25159420

Tsai, Chia-Ju; Lin, Ying-Chi; Chen, Yen-Ling; Feng, Chia-Hsien

2014-12-01

146

Product ion distributions for the reactions of NO+ with some physiologically significant aldehydes obtained using a SRI-TOF-MS instrument  

PubMed Central

Product ion distributions for the reactions of NO+ with 22 aldehydes involved in human physiology have been determined under the prevailing conditions of a selective reagent ionization time of flight mass spectrometry (SRI-TOF-MS) at an E/N in the flow/drift tube reactor of 130 Td. The chosen aldehydes were fourteen alkanals (the C2–C11 n-alkanals, 2-methyl propanal, 2-methyl butanal, 3-methyl butanal, and 2-ethyl hexanal), six alkenals (2-propenal, 2-methyl 2-propenal, 2-butenal, 3-methyl 2-butenal, 2-methyl 2-butenal, and 2-undecenal), benzaldehyde, and furfural. The product ion fragmentations patterns were determined for both dry air and humid air (3.5% absolute humidity) used as the matrix buffer/carrier gas in the drift tube of the SRI-TOF-MS instrument. Hydride ion transfer was seen to be a common ionization mechanism in all these aldehydes, thus generating (M?H)+ ions. Small fractions of the adduct ion, NO+M, were also seen for some of the unsaturated alkenals, in particular 2-undecenal, and heterocyclic furfural for which the major reactive channel was non-dissociative charge transfer generating the M+ parent ion. Almost all of the reactions resulted in partial fragmentation of the aldehyde molecules generating hydrocarbon ions; specifically, the alkanal reactions resulted in multiple product ions, whereas, the alkenals reactions produced only two or three product ions, dissociation of the nascent excited product ion occurring preferentially at the 2-position. The findings of this study are of particular importance for data interpretation in studies of aldehydes reactions employing SRI-TOF-MS in the NO+ mode.

Mochalski, Pawe?; Unterkofler, Karl; Špan?l, Patrik; Smith, David; Amann, Anton

2014-01-01

147

Collagen-based proteinaceous binder-pigment interaction study under UV ageing conditions by MALDI-TOF-MS and principal component analysis.  

PubMed

This study focuses on acquiring information on the degradation process of proteinaceous binders due to ultra violet (UV) radiation and possible interactions owing to the presence of historical mineral pigments. With this aim, three different paint model samples were prepared according to medieval recipes, using rabbit glue as proteinaceus binders. One of these model samples contained only the binder, and the other two were prepared by mixing each of the pigments (cinnabar or azurite) with the binder (glue tempera model samples). The model samples were studied by applying Principal Component Analysis (PCA) to their mass spectra obtained with Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF-MS). The complementary use of Fourier Transform Infrared Spectroscopy to study conformational changes of secondary structure of the proteinaceous binder is also proposed. Ageing effects on the model samples after up to 3000?h of UV irradiation were periodically analyzed by the proposed approach. PCA on MS data proved capable of identifying significant changes in the model samples, and the results suggested different aging behavior based on the pigment present. This research represents the first attempt to use this approach (PCA on MALDI-TOF-MS data) in the field of Cultural Heritage and demonstrates the potential benefits in the study of proteinaceous artistic materials for purposes of conservation and restoration. PMID:22431458

Romero-Pastor, Julia; Navas, Natalia; Kuckova, Stepanka; Rodríguez-Navarro, Alejandro; Cardell, Carolina

2012-03-01

148

Separation and identification of mouse liver membrane proteins using a gel-based approach in combination with 2DnanoLC-Q-TOF-MS/MS  

NASA Astrophysics Data System (ADS)

In this work, we present results of membrane proteome profiling from mouse liver tissues using a gel-based approach in combination with 2DnanoLC-Q-TOF-MS/MS. Following purification of the membrane fraction, SDS-PAGE was carried out as a useful separation step. After staining, gels with protein bands were cut, reduced, alkylated and trypsin-digested. The peptide mixtures extracted from each gel slice were fractionated by two-dimensional nano liquid chromatography (2DnanoLC) coupled online with tandem mass spectrometry analysis (NanoESI-Q-TOF-MS/MS). The proteins were identified by MASCOT search against a mouse protein database using a peptide and fragment mass tolerance of ±0.5?Da. Protein identification was carried out using a Mowse scoring algorithm with a confidence level of 95% and processed by MSQuant v1.5 software for further validation. In total, 318 verified membrane proteins from mouse liver tissues were identified; 66.67% of them (212 proteins) contained at least one or more transmembrane domains predicted by the SOSUI program and 43 were found to be unique microsome membranes. Furthermore, GRAVY values of membrane proteins varied in the range -1.1276 to 0.9016 and only 31 (9.76%) membrane proteins had positive values. The functions and subcellular locations of the identified proteins were categorized as well, according to universal GO annotations.

Thanh Tran, The; Phan, Van Chi

2010-03-01

149

VibrioBase: A MALDI-TOF MS database for fast identification of Vibrio spp. that are potentially pathogenic in humans.  

PubMed

Mesophilic marine bacteria of the family Vibrionaceae, specifically V. cholerae, V. parahaemolyticus and V. vulnificus, are considered to cause severe illness in humans. Due to climate-change-driven temperature increases, higher Vibrio abundances and infections are predicted for Northern Europe, which in turn necessitates environmental surveillance programs to evaluate this risk. We propose that whole-cell matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) profiling is a promising tool for the fast and reliable species classification of environmental isolates. Because the reference database does not contain sufficient Vibrio spectra we generated the VibrioBase database in this study. Mass spectrometric data were generated from 997 largely environmental strains and filed in this new database. MALDI-TOF MS clusters were assigned based on the species classification obtained by analysis of partial rpoB (RNA polymerase beta-subunit) sequences. The affiliation of strains to species-specific clusters was consistent in 97% of all cases using both approaches, and the extended VibrioBase generated more specific species identifications with higher matching scores compared to the commercially available database. Therefore, we have made the VibrioBase database freely accessible, which paves the way for detailed risk assessment studies of potentially pathogenic Vibrio spp. from marine environments. PMID:25466918

Erler, René; Wichels, Antje; Heinemeyer, Ernst-August; Hauk, Gerhard; Hippelein, Martin; Reyes, Nadja Torres; Gerdts, Gunnar

2015-02-01

150

Top-down proteomic identification of Shiga toxin 2 subtypes from Shiga toxin-producing Escherichia coli by Matrix-Assisted Laser Desorption Ionization-Tandem Time of Flight mass spectrometry  

Technology Transfer Automated Retrieval System (TEKTRAN)

We have analyzed 26 Shiga toxin-producing Escherichia coli (STEC) strains for Shiga toxin 2 (Stx2) production using matrix-assisted laser desorption/ionization time-of-flight-time-of-flight tandem mass spectrometry (MALDI-TOF-TOF-MS/MS) and top-down proteomic analysis. STEC strains were induced to ...

151

Development and Validation of an In-House Database for Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry-Based Yeast Identification Using a Fast Protein Extraction Procedure  

PubMed Central

In recent studies evaluating the usefulness of the matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS)-based identification of yeasts for the routine diagnosis of fungal infections, preanalytical sample processing has emerged as a critical step for reliable MALDI-TOF MS outcomes, especially when the Bruker Daltonics Biotyper software was used. In addition, inadequate results often occurred due to discrepancies between the methods used for clinical testing and database construction. Therefore, we created an in-house MALDI-TOF MS library using the spectra from 156 reference and clinical yeast isolates (48 species in 11 genera), which were generated with a fast sample preparation procedure. After a retrospective validation study, our database was evaluated on 4,232 yeasts routinely isolated during a 6-month period and fast prepared for MALDI-TOF MS analysis. Thus, 4,209 (99.5%) of the isolates were successfully identified to the species level (with scores of ?2.0), with 1,676 (39.6%) having scores of >2.3. For the remaining 23 (0.5%) isolates, no reliable identification (with scores of <1.7) was obtained. Interestingly, these isolates were almost always from species uniquely represented or not included in the database. As the MALDI-TOF MS results were, except for 23 isolates, validated without additional phenotypic or molecular tests, our proposed strategy can enhance the rapidity and accuracy of MALDI-TOF MS in identifying medically important yeast species. However, while continuous updating of our database will be necessary to enrich it with more strains/species of new and emerging yeasts, the present in-house MALDI-TOF MS library can be made publicly available for future multicenter studies. PMID:24554755

De Carolis, Elena; Vella, Antonietta; Vaccaro, Luisa; Torelli, Riccardo; Posteraro, Patrizia; Ricciardi, Walter; Posteraro, Brunella

2014-01-01

152

Plant lipidomics based on hydrophilic interaction chromatography coupled to ion trap time-of-flight mass spectrometry  

Microsoft Academic Search

Plants synthesize a wide range of hydrophobic compounds, generally known as lipids. Here, we report an application of liquid\\u000a chromatography ion trap time-of-flight mass spectrometry (LC-IT-TOF-MS) for plant lipidomics. Using hydrophilic interaction\\u000a chromatography (HILIC) for class separation, typical membrane lipids including glycerolipids, steryl glucosides and glucosylceramides,\\u000a and hydrophobic plant secondary metabolites such as saponins were analyzed simultaneously. By this method,

Yozo Okazaki; Yukiko Kamide; Masami Yokota Hirai; Kazuki Saito

153

Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Identifies Pseudomonas aeruginosa High-Risk Clones.  

PubMed

We show here that matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) accurately and quickly identified the five high-risk clones of Pseudomonas aeruginosa sequence type 111 (ST111), ST175, ST235, ST253, and ST395. The use of this screening technique by clinical microbiology laboratories may tackle the spread of high-risk clones by the quick implementation of hygiene control procedures for relevant patients. PMID:25653397

Cabrolier, Nadège; Sauget, Marlène; Bertrand, Xavier; Hocquet, Didier

2015-04-01

154

It's a MALDI but it's a goodie: MALDI-TOF mass spectrometry for microbial identification.  

PubMed

The last few years have witnessed a revolution in the diagnostic microbiology laboratory with the emergence of matrix assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) as an indispensible tool in microbial identification. In many laboratories this has superseded biochemical profiling. A mass spectrum is acquired from an unknown micro-organism and this proteomic fingerprint is then compared with a database of reference spectra to ascertain the likely genus and species identity. The reproducibility of this method is facilitated by the analysis of continually produced, highly abundant proteins (mainly ribosomal proteins) in the mass range 2000 to 20?000?Da. MALDI-TOF MS is reliable and rapid and has the ability to determine the identity of an isolate from culture in a matter of minutes rather than the hours or days required by more traditional methods. In addition to microbial identification of cultured isolates, work is underway to extend the utility of MALDI-TOF MS to include bacterial identification directly from clinical samples as well as providing timely information regarding antibiotic resistance and typing of different micro-organisms. PMID:24781219

Randell, Paul

2014-08-01

155

Optimizing Identification of Clinically Relevant Gram-Positive Organisms by Use of the Bruker Biotyper Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System  

PubMed Central

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) can be used as a method for the rapid identification of microorganisms. This study evaluated the Bruker Biotyper (MALDI-TOF MS) system for the identification of clinically relevant Gram-positive organisms. We tested 239 aerobic Gram-positive organisms isolated from clinical specimens. We evaluated 4 direct-smear methods, including “heavy” (H) and “light” (L) smears, with and without a 1-?l direct formic acid (FA) overlay. The quality measure assigned to a MALDI-TOF MS identification is a numerical value or “score.” We found that a heavy smear with a formic acid overlay (H+FA) produced optimal MALDI-TOF MS identification scores and the highest percentage of correctly identified organisms. Using a score of ?2.0, we identified 183 of the 239 isolates (76.6%) to the genus level, and of the 181 isolates resolved to the species level, 141 isolates (77.9%) were correctly identified. To maximize the number of correct identifications while minimizing misidentifications, the data were analyzed using a score of ?1.7 for genus- and species-level identification. Using this score, 220 of the 239 isolates (92.1%) were identified to the genus level, and of the 181 isolates resolved to the species level, 167 isolates (92.2%) could be assigned an accurate species identification. We also evaluated a subset of isolates for preanalytic factors that might influence MALDI-TOF MS identification. Frequent subcultures increased the number of unidentified isolates. Incubation temperatures and subcultures of the media did not alter the rate of identification. These data define the ideal bacterial preparation, identification score, and medium conditions for optimal identification of Gram-positive bacteria by use of MALDI-TOF MS. PMID:23426925

McElvania TeKippe, Erin; Shuey, Sunni; Winkler, David W.; Butler, Meghan A.

2013-01-01

156

Identification and Subtyping of Clinically Relevant Human and Ruminant Mycoplasmas by Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry  

PubMed Central

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) recently emerged as a technology for the identification of bacteria. In this study, we aimed to evaluate its applicability to human and ruminant mycoplasmal identification, which can be demanding and time-consuming when using phenotypic or molecular methods. In addition, MALDI-TOF MS was tested as a subtyping tool for certain species. A total of 29 main spectra (MSP) from 10 human and 13 ruminant mycoplasma (sub)species were included in a mycoplasma MSP database to complete the Bruker MALDI Biotyper database. After broth culture and protein extraction, MALDI-TOF MS was applied for the identification of 119 human and 143 ruminant clinical isolates that were previously identified by antigenic or molecular methods and for subcultures of 73 ruminant clinical specimens that potentially contained several mycoplasma species. MALDI-TOF MS resulted in accurate (sub)species-level identification with a score of ?1.700 for 96% (251/262) of the isolates. The phylogenetically closest (sub)species were unequivocally distinguished. Although mixtures of the strains were reliably detected up to a certain cellular ratio, only the predominant species was identified from the cultures of polymicrobial clinical specimens. For typing purposes, MALDI-TOF MS proved to cluster Mycoplasma bovis and Mycoplasma agalactiae isolates by their year of isolation and genome profiles, respectively, and Mycoplasma pneumoniae isolates by their adhesin P1 type. In conclusion, MALDI-TOF MS is a rapid, reliable, and cost-effective method for the routine identification of high-density growing mycoplasmal species and shows promising prospects for its capacity for strain typing. PMID:23903545

Renaudin, H.; Cauvin, E.; Del Prá Netto Machado, L.; Tricot, A.; Benoit, F.; Treilles, M.; Bébéar, C.

2013-01-01

157

Derivatization of organophosphorus nerve agent degradation products for gas chromatography with ICPMS and TOF-MS detection.  

PubMed

Separation and detection of seven V-type (venomous) and G-type (German) organophosphorus nerve agent degradation products by gas chromatography with inductively coupled plasma mass spectrometry (GC-ICPMS) is described. The nonvolatile alkyl phosphonic acid degradation products of interest included ethyl methylphosphonic acid (EMPA, VX acid), isopropyl methylphosphonic acid (IMPA, GB acid), ethyl hydrogen dimethylamidophosphate sodium salt (EDPA, GA acid), isobutyl hydrogen methylphosphonate (IBMPA, RVX acid), as well as pinacolyl methylphosphonic acid (PMPA), methylphosphonic acid (MPA), and cyclohexyl methylphosphonic acid (CMPA, GF acid). N-(tert-Butyldimethylsilyl)-N-methyltrifluroacetamide with 1% TBDMSCl was utilized to form the volatile TBDMS derivatives of the nerve agent degradation products for separation by GC. Exact mass confirmation of the formation of six of the TBDMS derivatives was obtained by GC-time of flight mass spectrometry (TOF-MS). The method developed here allowed for the separation and detection of all seven TBDMS derivatives as well as phosphate in less than ten minutes. Detection limits for the developed method were less than 5 pg with retention times and peak area precisions of less than 0.01 and 6%, respectively. This method was successfully applied to river water and soil matrices. To date this is the first work describing the analysis of chemical warfare agent (CWA) degradation products by GC-ICPMS. PMID:17356819

Richardson, Douglas D; Caruso, Joseph A

2007-06-01

158

Mass Spectrometry  

NASA Astrophysics Data System (ADS)

For twenty years or so now, mass spectrometry has been used to get exact measurements of the mass of biological molecules such as proteins, nucleic acids,oligosaccharides, and so on. Over the past ten years, this technology has followed the trend toward miniaturisation and the samples required can be much smaller. In particular, the nanoelectrospray source (online or by needle) allow one to work at flow rates of a few tens of nanolitres/min. There are many applications, both in the field of proteomics and in the analysis of protein structure, dynamics, and interactions. Combining this source with nanoHPLC, complex mixtures only available in small quantities can be separated and analysed online. There are also some advantages over conventional HPLC, despite a set of constraints related to the small dimensions and low flow rates. Combining capillary electrophoresis with the electrospray source also gives useful results, with its own set of advantages and constraints. Finally, developments are currently underway to combine this source with chips, providing a means of separation and analysis online.

Pflieger, D.; Forest, E.; Vinh, J.

159

Rapid Screening and Structural Characterization of Antioxidants from the Extract of Selaginella doederleinii Hieron with DPPH-UPLC-Q-TOF/MS Method  

PubMed Central

2,2-Diphenyl-1-picrylhydrazyl-ultra-high performance liquid chromatography-Q-time-of-flight mass spectrometry (DPPH-UPLC-Q-TOF/MS), as a rapid and efficient means, now was used for the first time to screen antioxidants from Selaginella doederleinii. The nine biflavone compounds were screened as potential antioxidants. The biflavones were structurally identified and divided into the three types, that is, amentoflavone-type, robustaflavone-type, and hinokiflavone-type biflavonoids. Among the compounds bilobetin (3) and putraflavone (8) were found from Selaginella doederleinii for the first time and others including amentoflavone (1), robustaflavone (2), 4?-methoxy robustaflavone (4), podocarpusflavone A (5), hinokiflavone (6), ginkgetin (7), and heveaflavone (9) were identified previously in the plant. Moreover, nine biflavones possessed a good antioxidant activity via their DPPH free radical scavenging. It demonstrates that DPPH-UPLC-Q-TOF/MS exhibits strong capacity in separation and identification for small molecule. The method is suitable for rapid screening of antioxidants without the need for complicated systems and additional instruments. PMID:25792983

Wang, Gang; Yao, Shun; Zhang, Xiu-Xiu; Song, Hang

2015-01-01

160

Antioxidant activity of leaf extracts from different Hibiscus sabdariffa accessions and simultaneous determination five major antioxidant compounds by LC-Q-TOF-MS.  

PubMed

Hibiscus sabdariffa has gained attention for its antioxidant activity. There are many accessions of H. sabdariffa in the world. However, information on the quantification of antioxidant compounds in different accessions is rather limited. In this paper, a liquid chromatography/quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS) method for simultaneous determination of five antioxidant compounds (neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, rutin, and isoquercitrin) in H. sabdariffa leaves was developed. The method was validated for linearity, sensitivity, precision, repeatability and accuracy. The validated method has been successfully applied for determination of the five analytes in eight accessions of H. sabdariffa. The eight accessions of H. sabdariffa were evaluated for their antioxidant activities by DPPH free radical scavenging assay. The investigated accessions of H. sabdariffa were rich in rutin and exhibited strong antioxidant activity. The two accessions showing the highest antioxidant activities were from Cuba (No. 2) and Taiwan (No. 5). The results indicated that H. sabdariffa leaves could be considered as a potential antioxidant source for the food industry. The developed LC-Q-TOF-MS method is helpful for quality control of H. sabdariffa. PMID:25525823

Wang, Jin; Cao, Xianshuang; Jiang, Hao; Qi, Yadong; Chin, Kit L; Yue, Yongde

2014-01-01

161

Application of hydrostatic CCC-TLC-HPLC-ESI-TOF-MS for the bioguided fractionation of anticholinesterase alkaloids from Argemone mexicana L. roots.  

PubMed

A rapid hydrostatic counter-current chromatography-thin-layer chromatography-electrospray-ionization time-of-flight mass spectrometry (CCC-TLC-ESI-TOF-MS) technique was established for use in seeking potent anti-Alzheimer's drugs among the acethylcholinesterase inhibitors in Argemone mexicana L. underground parts, with no need to isolate components in pure form. The dichloromethane extract from the roots of Mexican prickly poppy that was most rich in secondary metabolites was subjected to hydrostatic-CCC-based fractionation in descending mode, using a biphasic system composed of petroleum ether-ethyl acetate-methanol-water at the ratio of 1.5:3:2.1:2 (v/v). The obtained fractions were analyzed in a TLC-based AChE-inhibition "Fast Blue B" test. All active components in the fractions, including berberine, protopine, chelerithrine, sanguinarine, coptisine, palmatine, magnoflorine, and galanthamine, were identified in a direct TLC-HPLC-ESI-TOF-MS assay with high accuracy. This is the first time galanthamine has been reported in the extract of Mexican prickly poppy and the first time it has been identified in any member of the Papaveraceae family, in the significant quantity of 0.77 %. PMID:25618762

Kukula-Koch, Wirginia; Mroczek, Tomasz

2015-03-01

162

Evaluation of different extraction approaches for the determination of phenolic compounds and their metabolites in plasma by nanoLC-ESI-TOF-MS.  

PubMed

Sample preparation is an important step for the determination of phenolic compounds in biological samples. Different extraction methods have been tested to determine phenolic compounds and their metabolites in plasma by nano-liquid chromatography coupled to electrospray ionisation-time-of-flight mass spectrometry (nanoLC-ESI-TOF-MS). The sample treatment optimisation was performed using commercial foetal bovine serum spiked with representative phenolic standards, namely naringenin, luteolin, verbascoside, apigenin, rutin, syringic acid and catechin. Different protein-precipitation conditions were evaluated as well as enzymatic digestion with trypsin and solid-phase extraction using different phases such as C-18, ABN and ENV+, working at different pH values. The optimum extraction procedure consisted of a previous protein-precipitation step using HCl 200 mmol/L in methanol for 2.5 h at 50 °C followed by a solid-phase extraction using C-18 cartridges at pH 2.5. This procedure was finally applied to the plasma of rats overfed with a phenolic-rich Lippia citriodora extract. These samples were analysed by nanoLC-ESI-TOF-MS, enabling the identification of five compounds previously found in the administered L. citriodora extract and one metabolite. PMID:23064706

Quirantes-Piné, R; Verardo, V; Arráez-Román, D; Fernández-Arroyo, S; Micol, V; Caboni, M F; Segura-Carretero, A; Fernández-Gutiérrez, A

2012-12-01

163

Establishing Drug Resistance in Microorganisms by Mass Spectrometry  

NASA Astrophysics Data System (ADS)

A rapid method to determine drug resistance in bacteria based on mass spectrometry is presented. In it, a mass spectrum of an intact microorganism grown in drug-containing stable isotope-labeled media is compared with a mass spectrum of the intact microorganism grown in non-labeled media without the drug present. Drug resistance is determined by predicting characteristic mass shifts of one or more microorganism biomarkers using bioinformatics algorithms. Observing such characteristic mass shifts indicates that the microorganism is viable even in the presence of the drug, thus incorporating the isotopic label into characteristic biomarker molecules. The performance of the method is illustrated on the example of intact E. coli, grown in control (unlabeled) and 13C-labeled media, and analyzed by MALDI TOF MS. Algorithms for data analysis are presented as well.

Demirev, Plamen A.; Hagan, Nathan S.; Antoine, Miquel D.; Lin, Jeffrey S.; Feldman, Andrew B.

2013-08-01

164

Quantification of sterol lipids in plants by quadrupole time-of-flight mass spectrometry  

PubMed Central

Glycerolipids, sphingolipids, and sterol lipids constitute the major lipid classes in plants. Sterol lipids are composed of free and conjugated sterols, i.e., sterol esters, sterol glycosides, and acylated sterol glycosides. Sterol lipids play crucial roles during adaption to abiotic stresses and plant-pathogen interactions. Presently, no comprehensive method for sterol lipid quantification in plants is available. We used nanospray ionization quadrupole-time-of-flight mass spectrometry (Q-TOF MS) to resolve and identify the molecular species of all four sterol lipid classes from Arabidopsis thaliana. Free sterols were derivatized with chlorobetainyl chloride. Sterol esters, sterol glycosides, and acylated sterol glycosides were ionized as ammonium adducts. Quantification of molecular species was achieved in the positive mode after fragmentation in the presence of internal standards. The amounts of sterol lipids quantified by Q-TOF MS/MS were validated by comparison with results obtained with TLC/GC. Quantification of sterol lipids from leaves and roots of phosphate-deprived A. thaliana plants revealed changes in the amounts and molecular species composition. The Q-TOF method is far more sensitive than GC or HPLC. Therefore, Q-TOF MS/MS provides a comprehensive strategy for sterol lipid quantification that can be adapted to other tandem mass spectrometers. PMID:21382968

Wewer, Vera; Dombrink, Isabel; vom Dorp, Katharina; Dörmann, Peter

2011-01-01

165

Characterization of Bacteria in Ballast Water Using MALDI-TOF Mass Spectrometry  

PubMed Central

To evaluate a rapid and cost-effective method for monitoring bacteria in ballast water, several marine bacterial isolates were characterized by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Since International Maritime Organization (IMO) regulations are concerned with the unintended transportation of pathogenic bacteria through ballast water, emphasis was placed on detecting species of Vibrio, enterococci and coliforms. Seawater samples collected from the North Sea were incubated in steel ballast tanks and the presence of potentially harmful species of Pseudomonas was also investigated. At the genus-level, the identification of thirty six isolates using MALDI-TOF MS produced similar results to those obtained by 16S rRNA gene sequencing. No pathogenic species were detected either by 16S rRNA gene analysis or by MALDI-TOF MS except for the opportunistically pathogenic bacterium Pseudomonas aeruginosa. In addition, in house software that calculated the correlation coefficient values (CCV) of the mass spectral raw data and their variation was developed and used to allow the rapid and efficient identification of marine bacteria in ballast water for the first time. PMID:22685576

Emami, Kaveh; Askari, Vahid; Ullrich, Matthias; Mohinudeen, Khwajah; Anil, Arga Chandrashekar; Khandeparker, Lidita; Burgess, J. Grant; Mesbahi, Ehsan

2012-01-01

166

Mass Spectrometry Mass spectrometry has emerged as  

E-print Network

Mass Spectrometry Mass spectrometry has emerged as the key technology for proteomics experiments 3D protein structures at a proteome scale using mass spectrometry experiments. Data Analysis Data and the development of suitable data analysis routines is a major challenge. Structural Proteomics Proteomics

Heermann, Dieter W.

167

Rapid identification and source-tracking of Listeria monocytogenes using MALDI-TOF mass spectrometry.  

PubMed

Listeria monocytogenes is an important foodborne pathogen responsible for the sometimes fatal disease listeriosis. Public health concerns and stringent regulations associated with the presence of this pathogen in food and food processing environments underline the need for rapid and reliable detection and subtyping techniques. In the current study, the application of matrix assisted laser desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS) as a single identification and source-tracking tool for a collection of L. monocytogenes isolates, obtained predominantly from dairy sources within Australia, was explored. The isolates were cultured on different growth media and analysed using MALDI-TOF MS at two incubation times (24 and 48h). Whilst reliable genus-level identification was achieved from most media, identification at the species level was found to be dependent on culture conditions. Successful speciation was highest for isolates cultured on the chromogenic Agar Listeria Ottaviani Agosti agar (ALOA, 91% of isolates) and non-selective horse blood agar (HBA, 89%) for 24h. Chemometric statistical analysis of the MALDI-TOF MS data enabled source-tracking of L. monocytogenes isolates obtained from four different dairy sources. Strain-level discrimination was also observed to be influenced by culture conditions. In addition, t-test/analysis of variance (ANOVA) was used to identify potential biomarker peaks that differentiated the isolates according to their source of isolation. Source-tracking using MALDI-TOF MS was compared and correlated with the gold standard pulsed-field gel electrophoresis (PFGE) technique. The discriminatory index and the congruence between both techniques were compared using the Simpsons Diversity Index and adjusted Rand and Wallace coefficients. Overall, MALDI-TOF MS based source-tracking (using data obtained by culturing the isolates on HBA) and PFGE demonstrated good congruence with a Wallace coefficient of 0.71 and comparable discriminatory indices of 0.89 and 0.86, respectively. MALDI-TOF MS thus represents a rapid and cost-effective source-tracking technique for L. monocytogenes. PMID:25747262

Jadhav, Snehal; Gulati, Vandana; Fox, Edward M; Karpe, Avinash; Beale, David J; Sevior, Danielle; Bhave, Mrinal; Palombo, Enzo A

2015-06-01

168

Simultaneous determination nucleosides in marine organisms using ultrasound-assisted extraction followed by hydrophilic interaction liquid chromatography-electrospray ionization time-of-flight mass spectrometry.  

PubMed

A new method has been developed based on ultrasound-assisted extraction (UAE) followed by hydrophilic interaction chromatography (HILIC) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF/MS) for the simultaneous determination of 16 nucleosides and nucleobases in medicinal extracts of various marine organisms. The separation was achieved on a Venusil HILIC column (250×4.6 mm id, 5 ?m) and gradient elution using a solution of acetonitrile and buffer (0.20% formic acid and 20 mmol/L ammonium acetate) as the mobile phase. Identification of the 16 target nucleosides and nucleobases was based on the retention time, UV spectra, and mass measurements of the protonated molecules ([M+H](+)) and main fragment ions (ESI-TOF/MS). In addition, non-target compounds of 2'-deoxyinosine and four other amino acids were also tentatively identified by ESI-TOF/MS. The 16 target compounds were quantified by HILIC-ESI-TOF/MS under optimized mass conditions. All calibration curves showed good linearity (r(2)>0.9951). The recoveries were 84.72-124.10%, and the limits of detection of the 16 target compounds were 0.6-130.0 ng/mL. The developed method was applied to quantify the target compounds in 15 batches of various marine organisms. The method has potential applicability for the identification and determination of highly polar and low-concentration active compounds in marine organisms. PMID:21837626

Zhao, Hengqiang; Chen, Junhui; Shi, Qian; Li, Xin; Zhou, Wenhui; Zhang, Daolai; Zheng, Li; Cao, Wei; Wang, Xiaoru; Lee, Frank Sen-Chun

2011-10-01

169

The power of hyphenated chromatography/time-of-flight mass spectrometry in public health laboratories.  

PubMed

Laboratories devoted to the public health field have to face the analysis of a large number of organic contaminants/residues in many different types of samples. Analytical techniques applied in this field are normally focused on quantification of a limited number of analytes. At present, most of these techniques are based on gas chromatography (GC) or liquid chromatography (LC) coupled to tandem mass spectrometry (MS/MS). Using these techniques only analyte-specific information is acquired, and many other compounds that might be present in the samples would be ignored. In this paper, we explore the potential of time-of-flight (TOF) MS hyphenated to GC or LC to provide additional information, highly useful in this field. Thus, all positives reported by standard reference targeted LC-MS/MS methods were unequivocally confirmed by LC-QTOF MS. Only 61% of positives reported by targeted GC-MS/MS could be confirmed by GC-TOF MS, which was due to its lower sensitivity as nonconfirmations corresponded to analytes that were present at very low concentrations. In addition, the use of TOF MS allowed searching for additional compounds in large-scope screening methodologies. In this way, different contaminants/residues not included in either LC or GC tandem MS analyses were detected. This was the case of the insecticide thiacloprid, the plant growth regulator paclobutrazol, the fungicide prochloraz, or the UV filter benzophenone, among others. Finally, elucidation of unknowns was another of the possibilities offered by TOF MS thanks to the accurate-mass full-acquisition data available when using this technique. PMID:22578112

Ibáñez, María; Portolés, Tania; Rúbies, Antoni; Muñoz, Eva; Muñoz, Gloria; Pineda, Laura; Serrahima, Eulalia; Sancho, Juan V; Centrich, Francesc; Hernández, Félix

2012-05-30

170

Characterisation of the aerobic bacterial flora of boid snakes: application of MALDI-TOF mass spectrometry.  

PubMed

The aim of this study was to identify aerobic bacterial isolates from the respiratory tract of boids with matrix-assisted laser desorption ionisation-time-of-flight mass spectrometry (MALDI-TOF MS). From 47 boid snakes, swabs from the oral cavity, tracheal wash samples and, in cases in which postmortem examination was performed, pulmonary tissue samples were taken. Each snake was classified as having inflammation of the respiratory tract and/or oral cavity, or without evidence of inflammation based on combination of clinical, cytological and histopathological findings. Samples collected from the respiratory tract and oral cavity were inoculated onto routine media and bacteria were cultured aerobically. All morphologically distinct individual colonies obtained were analysed using MALDI-TOF MS. Unidentified isolates detected in more than three snakes were selected for further 16S rDNA PCR and sequencing. Among all examined isolates (n=243), 49 per cent (n=119) could be sufficiently speciated using MALDI-TOF MS. Molecular biology revealed several bacterial species that have not been previously described in reptiles. With an average of 6.3 different isolates from the respiratory tract and/or oral cavity, boids with inflammatory disease harboured significantly more bacterial species than boids without inflammatory disease (average 2.8 isolates). PMID:25487809

Plenz, Bastian; Schmidt, Volker; Grosse-Herrenthey, Anke; Krüger, Monika; Pees, Michael

2015-03-14

171

Mass spectrometry for direct identification of biosignatures and microorganisms in Earth analogs of Mars  

NASA Astrophysics Data System (ADS)

Rover missions to Mars require portable instruments that use minimal power, require no sample preparation, and provide suitably diagnostic information to an Earth-based exploration team. In exploration of analog environments of Mars it is important to screen rapidly for the presence of biosignatures and microorganisms and especially to identify them accurately. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) has enormously contributed to the understanding of protein chemistry and cell biology. Without this technique proteomics would most likely not be the important discipline it is today. In this study, besides 'true' proteomics, MALDI-TOF-MS was applied for the analysis of microorganisms for their taxonomic characterization from its beginning. An approach was developed for direct analysis of whole bacterial cells without a preceding fractionation or separation by chromatography or electrophoresis on samples of bacteria from an Antarctic glacier. Supported by comprehensive databases, MALDI-TOF-MS-based identification could be widely accepted within only a few years for bacterial differentiation in Mars analogs and could be a technique of election for Mars exploration.

Garcia-Descalzo, Laura; García-López, Eva; Maria Moreno, Ana; Alcazar, Alberto; Baquero, Fernando; Cid, Cristina

2012-11-01

172

Detection of drugs and their metabolites in dusted latent fingermarks by mass spectrometry.  

PubMed

A hydrophobic silica dusting agent containing carbon black has been used with latent finger marks to demonstrate that the agent can act as an enhancing matrix to generate a simple method for detecting a range of drugs using surface assisted laser desorption/ionisation time-of-flight mass spectrometry (SALDI-TOF-MS) in positive ion reflectron mode. The dusting agent produces developed marks for locating/visualising the prints whilst also acting as a SALDI-TOF-MS enhancer that is equivalent to the standard matrix enhancer 2,5-dihydroxybenzoic acid. This method has been applied to the analysis of latent fingermarks for contact residues on fingers, and for detection of illicit drugs for both parent drugs and their metabolites. Analysis was performed by direct MS analysis of the pre-dusted fingermarks on the surface of a target plate and, following lifting using commercial tape, MS analysis of the lifted marks. When 19 commercial powders were used only three produced MS spectra but with intensities less than those produced with the new powder. The presence of the parent drug and its metabolites was confirmed using SALDI-TOF-MS-MS following high energy collision induced dissociation when characteristic and unique fragmentation patterns were observed in each case. The distribution of these compounds on fingermarks was subsequently demonstrated using commercially available imaging software. PMID:19305918

Rowell, Frederick; Hudson, Katherine; Seviour, John

2009-04-01

173

What Is New in Clinical Microbiology—Microbial Identification by MALDI-TOF Mass Spectrometry  

PubMed Central

Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) offers the possibility of accurate, rapid, inexpensive identification of bacteria, fungi, and mycobacteria isolated in clinical microbiology laboratories. The procedures for preanalytic processing of organisms and analysis by MALDI-TOF MS are technically simple and reproducible, and commercial databases and interpretive algorithms are available for the identification of a wide spectrum of clinically significant organisms. Although only limited work has been reported on the use of this technique to identify molds, perform strain typing, or determine antibiotic susceptibility results, these are fruitful areas of promising research. As experience is gained with MALDI-TOF MS, it is expected that the databases will be expanded to resolve many of the current inadequate identifications (eg, no identification, genus-level identification) and algorithms for potential misidentification will be developed. The current lack of Food and Drug Administration approval of any MALDI-TOF MS system for organism identification limits widespread use in the United States. PMID:22795961

Murray, Patrick R.

2012-01-01

174

The ongoing revolution of maldi-tof mass spectrometry for microbiology reaches tropical Africa.  

PubMed

Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) represents a revolution in routine pathogen identification in clinical microbiology laboratories. A MALDI-TOF MS was introduced to tropical Africa in the clinical microbiology laboratory of the Hôpital Principal de Dakar (Senegal) and used for routine pathogen identification. Using MS, 2,429 bacteria and fungi isolated from patients were directly assayed, leading to the identification of 2,082 bacteria (85.7%) and 206 fungi (8.5%) at the species level, 109 bacteria (4.5%) at the genus level, and 16 bacteria (0.75%) at the family level. Sixteen isolates remained unidentified (0.75%). Escherichia coli was the most prevalent species (25.8%) followed by Klebsiella pneumoniae (14.8%), Streptococcus agalactiae (6.2%), Acinetobacter baumannii (6.1%), Pseudomonas aeruginosa (5.9%), and Staphylococcus aureus (5.9%). MALDI-TOF MS has also enabled the detection of rare bacteria and fungi. MALDI-TOF MS is a powerful tool for the identification of bacterial and fungal species involved in infectious diseases in tropical Africa. PMID:25601995

Fall, Bécaye; Lo, Cheikh Ibrahima; Samb-Ba, Bissoume; Perrot, Nadine; Diawara, Silman; Gueye, Mamadou Wague; Sow, Kowry; Aubadie-Ladrix, Maxence; Mediannikov, Oleg; Sokhna, Cheikh; Diemé, Yaya; Chatellier, Sonia; Wade, Boubacar; Raoult, Didier; Fenollar, Florence

2015-03-01

175

Identification of Medically Relevant Species of Arthroconidial Yeasts by Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry  

PubMed Central

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) was used for an extensive identification study of arthroconidial yeasts, using 85 reference strains from the CBS-KNAW yeast collection and 134 clinical isolates collected from medical centers in Qatar, Greece, and Romania. The test set included 72 strains of ascomycetous yeasts (Galactomyces, Geotrichum, Saprochaete, and Magnusiomyces spp.) and 147 strains of basidiomycetous yeasts (Trichosporon and Guehomyces spp.). With minimal preparation time, MALDI-TOF MS proved to be an excellent diagnostic tool that provided reliable identification of most (98%) of the tested strains to the species level, with good discriminatory power. The majority of strains were correctly identified at the species level with good scores (>2.0) and seven of the tested strains with log score values between 1.7 and 2.0. The MALDI-TOF MS results obtained were consistent with validated internal transcribed spacer (ITS) and/or large subunit (LSU) ribosomal DNA sequencing results. Expanding the mass spectrum database by increasing the number of reference strains for closely related species, including those of nonclinical origin, should enhance the usefulness of MALDI-TOF MS-based diagnostic analysis of these arthroconidial fungi in medical and other laboratories. PMID:23678074

Kolecka, Anna; Khayhan, Kantarawee; Groenewald, Marizeth; Theelen, Bart; Arabatzis, Michael; Velegraki, Aristea; Kostrzewa, Markus; Mares, Mihai; Taj-Aldeen, Saad J.

2013-01-01

176

[Analysis and identification of chemical constituents in Siwu decoction by UPLC-Q-TOF-MS(E)].  

PubMed

This research analyzed the chemical constituents of Siwu decoction by UPLC-Q-TOF-MS(E). Base on the data of mass and related-literatures, 43 peaks were profiled and 25 compounds, which contain 8 monoterpene glycosides from Paeonia lactiflora and 13 phthalides from Rhizoma chuanxiong and Radix angelica sinensis mainly, were identified in both positive and negative mode respectively. Meanwhile, chemical constituents of water extract and 60% ethanol extract of Siwu decoction were compared by the principal constituent analysis with MarkerLynx software, which provides the basis for the active ingredients of Siwu decoction. PMID:24494558

Wang, Zhen-Fang; Zhao, Yang; Pang, Xu; Yu, He-Shui; Kang, Li-Ping; Gao, Yue; Ma, Bai-Ping

2013-11-01

177

Protein identification from two-dimensional gel electrophoresis analysis of Klebsiella pneumoniae by combined use of mass spectrometry data and raw genome sequences  

Microsoft Academic Search

Separation of proteins by two-dimensional gel electrophoresis (2-DE) coupled with identification of proteins through peptide mass fingerprinting (PMF) by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is the widely used technique for proteomic analysis. This approach relies, however, on the presence of the proteins studied in public-accessible protein databases or the availability of annotated genome sequences of an

Wei Wang; Jibin Sun; Manfred Nimtz; Wolf-Dieter Deckwer; An-Ping Zeng

2003-01-01

178

A Sensitive and Effective Proteomic Approach to Identify She-Donkey’s and Goat’s Milk Adulterations by MALDI-TOF MS Fingerprinting  

PubMed Central

She-donkey’s milk (DM) and goat’s milk (GM) are commonly used in newborn and infant feeding because they are less allergenic than other milk types. It is, therefore, mandatory to avoid adulteration and contamination by other milk allergens, developing fast and efficient analytical methods to assess the authenticity of these precious nutrients. In this experimental work, a sensitive and robust matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) profiling was designed to assess the genuineness of DM and GM milks. This workflow allows the identification of DM and GM adulteration at levels of 0.5%, thus, representing a sensitive tool for milk adulteration analysis, if compared with other laborious and time-consuming analytical procedures. PMID:25110863

Di Girolamo, Francesco; Masotti, Andrea; Salvatori, Guglielmo; Scapaticci, Margherita; Muraca, Maurizio; Putignani, Lorenza

2014-01-01

179

Identification of Lactobacillus from the Saliva of Adult Patients with Caries Using Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry  

PubMed Central

Matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) has been presented as a superior method for the detection of microorganisms in body fluid samples (e.g., blood, saliva, pus, etc.) However, the performance of MALDI-TOF MS in routine identification of caries-related Lactobacillus isolates from saliva of adult patients with caries has not been determined. In the present study, we introduced a new MALDI-TOF MS system for identification of lactobacilli. Saliva samples were collected from 120 subjects with caries. Bacteria were isolated and cultured, and each isolate was identified by both 16S rRNA sequencing and MALDI-TOF MS. The identification results obtained by MALDI-TOF MS were concordant at the genus level with those of conventional 16S rRNA-based sequencing for 88.6% of lactobacilli (62/70) and 95.5% of non-lactobacilli (21/22). Up to 96 results could be obtained in parallel on a single MALDI target, suggesting that this is a reliable high-throughput approach for routine identification of lactobacilli. However, additional reference strains are necessary to increase the sensitivity and specificity of species-level identification. PMID:25166027

Ma, Qingwei; Song, Yeqing; Zhang, Qian; Wang, Xiaoyan; Chen, Feng

2014-01-01

180

MALDI-TOF mass spectrometry-based identification of group A Streptococcus isolated from areas of the 2011 scarlet fever outbreak in china.  

PubMed

There was a dramatic increase in scarlet fever cases in China from March to July 2011. Group A Streptococcus (GAS) is the only pathogen known to cause scarlet fever. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) coupled to Biotyper system was used for GAS identification in 2011. A local reference database (LRD) was constructed, evaluated and used to identify GAS isolates. The 75 GAS strains used to evaluate the LRD were all identified correctly. Of the 157 suspected ?-hemolytic strains isolated from 298 throat swab samples, 127 (100%) and 120 (94.5%) of the isolates were identified as GAS by the MALDI-TOF MS system and the conventional bacitracin sensitivity test method, respectively. All 202 (100%) isolates were identified at the species level by searching the LRD, while 182 (90.1%) were identified by searching the original reference database (ORD). There were statistically significant differences with a high degree of credibility at species level (?(2)=6.052, P<0.05 between the LRD and ORD). The test turnaround time was shortened 36-48h, and the cost of each sample is one-tenth of the cost of conventional methods. Establishing a domestic database is the most effective way to improve the identification efficiency using a MALDI-TOF MS system. MALDI-TOF MS is a viable alternative to conventional methods and may aid in the diagnosis and surveillance of GAS. PMID:23305889

Xiao, Di; You, Yuanhai; Bi, Zhenwang; Wang, Haibin; Zhang, Yongchan; Hu, Bin; Song, Yanyan; Zhang, Huifang; Kou, Zengqiang; Yan, Xiaomei; Zhang, Menghan; Jin, Lianmei; Jiang, Xihong; Su, Peng; Bi, Zhenqiang; Luo, Fengji; Zhang, Jianzhong

2013-03-01

181

Ni speciation in tea infusions by monolithic chromatography--ICP-MS and Q-TOF-MS.  

PubMed

For humans, Ni is not considered to be an essential trace element. Its compounds, at levels present in foodstuffs and drinks, are generally considered to be safe for consumption, but for individuals who already suffer from contact allergy to Ni and may be subject to develop systemic reactions from its dietary ingestion, dietary exposure to Ni must be kept under control. Being the second most popular beverage, tea is a potential source of dietary Ni. Present knowledge on its speciation in tea infusions is poor. Therefore, complete speciation analysis, consisting of separation by liquid chromatography using a weak CIM DEAE-1 monolithic column, "on-line" detection by inductively coupled plasma mass spectrometry (ICP-MS) and "off-line" identification of ligands by hybrid quadrupole time-of-flight mass spectrometry (Q-TOF MS), was implemented for the first time to study Ni speciation in tea infusions. Total concentrations of Ni in dry leaves of white, green, oolong and black tea (Camellia sinensis) and flowers of herbal chamomile (Matricaria chamomilla) and hibiscus (Hibiscus sabdariffa) tea were determined after microwave digestion by ICP-MS. They lay between 1.21 and 14.4 mg kg(-1). Good agreement between the determined and the certified values of the Ni content in the standard reference material SRM 1573a tomato leaves confirmed the accuracy of the total Ni determination. During the infusion process, up to 85 % of Ni was extracted from tea leaves or flowers. Separation of Ni species was completed in 10 min by applying aqueous linear gradient elution with 0.6 mol L(-1) NH(4)NO(3). Ni was found to be present in the chromatographic fraction in which quinic acid was identified by Q-TOF in all the tea infusions analysed, which had pH values between 5.6 and 6.0. The only exception was the infusion of hibiscus tea with a pH of 2.7, where results of speciation analysis showed that Ni is present in its divalent ionic form. PMID:23232960

Š?an?ar, Janez; Zuliani, Tea; Žigon, Dušan; Mila?i?, Radmila

2013-02-01

182

Pharmacokinetic study of ginsenoside Rc and simultaneous determination of its metabolites in rats using RRLC-Q-TOF-MS.  

PubMed

A rapid resolution liquid chromatography coupled with quadruple-time-of-flight mass spectrometry (RRLC-Q-TOF-MS) method was developed for pharmacokinetic study of ginsenoside Rc and applied in the simultaneous determination of ginsenoside Rc metabolites in rats. The experimental results indicate that the concentration versus time profile of ginsenoside Rc shows a two-compartment pharmacokinetic model after intravenous administration of ginsenoside Rc at a dosage of 0.4mg/kg for rats. In the metabolic study, prototype ginsenoside Rc and its deglycosylated metabolites Mb, Mc, and compound K were characterized by comparing the retention time (tR), accurate mass, and characteristic MS/MS fragment ions with standard compounds. The experiments show that part of the ginsenoside Rc was excreted through urine as prototype and part was metabolized into metabolites Mb and Mc after intravenous administration. In contrast, most of ginsenoside Rc were transformed into Mc and CK in feces after oral administration. The in vivo metabolic pathway of ginsenoside Rc was summarized. PMID:24013032

Sun, Jinghui; Wu, Wei; Guo, Yingying; Qin, Qiujie; Liu, Shuying

2014-01-01

183

Potato glycoalkaloids in soil-optimising liquid chromatography-time-of-flight mass spectrometry for quantitative studies.  

PubMed

Potato glycoalkaloids are produced in high amounts in potato fields during the growth season and losses to soil potentially impact shallow groundwater and via tiles to fresh water ecosystems. A quantitative liquid chromatography-electrospray ionization time-of-flight mass spectrometry (LC-ESI-TOF-MS) method for determination and quantification of potato glycoalkaloids and their metabolites in aqueous soil extracts was developed. The LC-ESI-TOF-MS method had linearities up to 2000microg/L for alpha-solanine and alpha-chaconine and up to 760microg/L for solanidine. No matrix effect was observed, and the detection limits found were in the range 2.2-4.7microg/L. The method enabled quantification of the potato glycoalkaloids in environmental samples. PMID:18221744

Jensen, Pia H; Juhler, René K; Nielsen, Nikoline J; Hansen, Thomas H; Strobel, Bjarne W; Jacobsen, Ole S; Nielsen, John; Hansen, Hans Christian B

2008-02-22

184

Electrosprayed droplet impact/secondary ion mass spectrometry  

NASA Astrophysics Data System (ADS)

A new ionization method, electrosprayed droplet impact ionization (EDI), has been developed for mass spectrometry. The charged droplets formed by electrospraying 1 M acetic acid aqueous solution are sampled through an orifice with a diameter of 400 ?m into the first vacuum chamber, transported into a quadrupole ion guide and accelerated by 10 kV after exiting the ion guide. The m/z of the primary droplet projectiles range from 10 000 to 50 000. The droplets impact on a dry solid sample deposited on a stainless steel substrate. No matrix was used for the sample preparation. The secondary ions formed by the impact are transported to a second quadrupole ion guide and mass-analyzed by an orthogonal TOF-MS. Intense molecular-related ions are detected for drugs, amino acids, peptides and proteins. EDI is found to be very sensitive to molecules present near the surface of the sample.

Hiraoka, K.; Asakawa, D.; Fujimaki, S.; Takamizawa, A.; Mori, K.

2006-04-01

185

Development of soft extraction method for structural characterization of boreal forest soil proteins with MALDI-TOF/MS  

NASA Astrophysics Data System (ADS)

Nitrogen (N) is usually the nutrient restricting productivity in boreal forests. Forest soils contain a great amount of nitrogen, but only a small part of it is in mineral form. Most part of soil N is bound in the structures of different organic compounds such as proteins, peptides, amino acids and more stabilized, refractory compounds. Due to the fact that soil organic N has a very important role in soil nutrient cycling and in plant nutrition, there is a need for more detailed knowledge of its chemistry in soil. Conventional methods to extract and analyze soil organic N are usually very destructive for structures of higher molecular weight organic compounds, such as proteins. The aim of this study was to characterize proteins extracted from boreal forest soil by "soft" extraction methods in order to maintain their molecular structure. The organic layer (F) from birch forest floor containing 78% of organic matter was sieved, freeze dried, pulverized, and extracted with a citrate or phosphate buffer (pH 6 or 8). Sequential extraction with the citrate or phosphate buffer and an SDS buffer (pH 6.8), slightly modified from the method of Chen et al. (2009, Proteomics 9: 4970-4973), was also done. Proteins were purified from the soil extract by extraction with buffered phenol and precipitated with methanol + 0.1M ammonium acetate at -20°C. Characterization of proteins was performed with matrix assisted laser desorption ionization - time-of-flight mass spectrometry (MALDI-TOF/MS) and the concentration of total proteins was measured using Bradford's method. Bovine serum albumin (BSA) was used as a positive control in the extractions and as a standard protein in Bradford's method. Our results showed that sequential extraction increased the amount of extracted proteins compared to the extractions without the SDS-buffer; however, it must be noted that the use of SDS-buffer very probably increased denaturization of proteins. Purification of proteins from crude soil extracts by phenol extraction was essential prior to measurement of total proteins; there seemed to be a lot of compounds in crude soil extracts that interfere with the analysis of total proteins, causing overestimation in protein concentration. pH of the buffer solution did not seem to be very crucial for the extractability of soil natural proteins, but at the higher pH, the amount of interfering compounds increased. However, the recovery of BSA added was clearly higher at the higher pH. When the protein precipitates were analyzed with MALDI-TOF/MS, a large curve, most likely formed from wide peaks of several compounds, indicate that most of the compounds in the precipitate were <15 kDa or ~20-50 kDa in molecular weight. It seems that in order to identify individual proteins from mass spectra, a separation of compounds with varying molecular weight is needed before the MALDI-TOF/MS analysis. Due to the fact that a relatively high amount of BSA added was not recovered by the extractions and that the intensity of the signals observed in mass spectra was low, it is questionable whether it is possible to extract soil natural proteins effectively from soils containing a high amount of organic matter without destructing the structures of proteins.

Kanerva, Sanna; Ketola, Raimo A.; Kitunen, Veikko; Smolander, Aino; Kotiaho, Tapio

2010-05-01

186

Hybrid Ion-Detector/Data-Acquisition System for a TOF-MS  

NASA Technical Reports Server (NTRS)

A modified ion-detector/data-acquisition system has been devised to increase the dynamic range of a time-of-flight mass spectrometer (TOF-MS) that, previously, included a microchannel-plate detector and a data-acquisition system based on counting pulses and time-tagging them by use of a time-to-digital converter (TDC). The dynamic range of the TOF-MS was limited by saturation of the microchannel plate detector, which can handle no more than a few million counts per second. The modified system includes (1) a combined microchannel plate/discrete ion multiplier and (2) a hybrid data-acquisition system that simultaneously performs analog current or voltage measurements and multianode single-ion-pulse-counting time-of-flight measurements to extend the dynamic range of a TDC into the regime in which a mass peak comprises multiple ions arriving simultaneously at the detector. The multianode data are used to determine, in real time, whether the detector is saturated. When saturation is detected, the data-acquisition system selectively enables circuitry that simultaneously determines the ion-peak intensity by measuring the time profile of the analog current or voltage detector-output signal.

Burton, William D., Jr.; Schultz, J. Albert; Vaughn, Valentine; McCully, Michael; Ulrich, Steven; Egan, Thomas F.

2006-01-01

187

A method for the detection of antibiotic resistance markers in clinical strains of Escherichia coli using MALDI mass spectrometry.  

PubMed

Matrix-assisted laser-desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) is one of the most widely used mass spectrometry based approaches for bacterial identification and classification. The relatively simple sample preparation requirements and the speed of analysis which can usually be completed within a few minutes have resulted in the adoption and assimilation of MALDI-TOF MS into the routine diagnostic workflow of Clinical microbiology laboratories worldwide. This study describes the facilitation of bacterial discrimination based on antibiotic resistance markers through the implementation of MALDI-TOF MS. The periplasmic compartment of whole bacterial cells contains several proteins which confer antibiotic resistance in the Enterobacteriaceae. In order to reduce the complexity of the sample to be analysed via MALDI-TOF MS, the periplasm was extracted and subjected to in solution tryptic digestion followed by nano-LC separation. This method, established that peptide sequence biomarkers from several classes of antibiotic resistance proteins could be predicted using protein/peptide database tools such as Mascot. Biomarkers for a CTX-M-1 group extended spectrum ?-lactamase, CMY-2 an Amp-C ?-lactamase, VIM a metallo-?-lactamase, TEM a ?-lactamase and KanR an aminoglycoside modifying enzyme were detected. This allowed for discrimination at a species level and at an almost identical strain level where the only difference between strains was the carriage of a modified antibiotic resistance carrying plasmid. This method also was able to detect some of these biomarkers in clinical strains where multiple resistance mechanisms were present. PMID:25633625

Hart, Philippa J; Wey, Emmanuel; McHugh, Timothy D; Balakrishnan, Indran; Belgacem, Omar

2015-04-01

188

Characterization of Proteins Utilized in the Desulfurization of Petroleum Products by Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry  

Microsoft Academic Search

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI\\/TOF\\/MS) with delayed extraction is utilized in linear, reflected-ion and post-source decay (PSD) modes to directly characterize enzymes being developed for use in a petroleum desulfurization process. The DNA sequence for the genes isolated fromRhodococcussp. strain IGTS8 that produce three of the four enzymes under study had been previously reported with a discrepancy

Barbara P. Wolf; Lloyd W. Sumner; Sharon J. Shields; Kurt Nielsen; Kevin A. Gray; David H. Russell

1998-01-01

189

Fast analysis of volatile organic compounds and disinfection by-products in drinking water using solid-phase microextraction–gas chromatography\\/time-of-flight mass spectrometry  

Microsoft Academic Search

A fast method was developed for the extraction and analysis of volatile organic compounds, including disinfection by-products (DBPs), with headspace solid-phase microextraction (HS-SPME) and gas chromatography\\/mass spectrometry (GC\\/MS) techniques. A GC\\/time-of-flight (TOF)–MS instrument, which had fast acquisition rates and powerful deconvolution software, was used. Under optimum conditions total runtime was 45s. Volatile organic compounds (VOCs), including purgeable A and B

Vadoud H. Niri; Leslie Bragg; Janusz Pawliszyn

2008-01-01

190

Effect of a traditional Chinese medicine preparation Xindi soft capsule on rat model of acute blood stasis: A urinary metabonomics study based on liquid chromatography–mass spectrometry  

Microsoft Academic Search

Xindi soft capsule is a traditional Chinese medicine preparation which consists of sea buckthorn flavonoids and sea buckthorn berry oil. In this study, a urinary metabonomics method based on the ultra-performance liquid chromatography combined with quadrupole time-of-flight tandem mass spectrometry (UPLC Q-TOF MS) was used to evaluate the efficacy and study the mechanism of traditional Chinese medicine preparation to blood

Xinjie Zhao; Yi Zhang; Xianli Meng; Peiyuan Yin; Chong Deng; Jing Chen; Zhang Wang; Guowang Xu

2008-01-01

191

Evaluation of the Bruker Biotyper Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Identification of Blood Isolates of Acinetobacter Species  

PubMed Central

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) (Bruker Biotyper) was able to accurately identify 98.6% (142/144) of Acinetobacter baumannii isolates, 72.4% (63/87) of A. nosocomialis isolates, and 97.6% (41/42) of A. pittii isolates. All Acinetobacter junii, A. ursingii, A. johnsonii, and A. radioresistens isolates (n = 28) could also be identified correctly by Bruker Biotyper. PMID:24899038

Hsueh, Po-Ren; Kuo, Lu-Cheng; Chang, Tsung-Chain; Lee, Tai-Fen; Teng, Shih-Hua; Chuang, Yu-Chung; Teng, Lee-Jene

2014-01-01

192

Constituent analysis and quality control of Lamiophlomis rotata by LC-TOF/MS and HPLC-UV.  

PubMed

In the present study, chemical profile analysis for Lamiophlomis rotata, a classic Tibetan folk medicine, was illustrated by an ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry (LC-TOF/MS) method, which provided evidence for the certain identification of the main constituents, including iridoids, flavonoids and phenylethanoid glycosides. Among these compounds, nine of them were regarded as marker compounds for the quantitative evaluation of L. rotata, using a simple and reliable method by HPLC with ultraviolet, in combination of chromatographic fingerprint analysis. Separation was achieved on a Waters SunFire C18 analytical column with linear gradient elution of acetonitrile and 0.1% formic acid aqueous solution. The validated method was successfully applied to evaluate twelve batches of L. rotata. Assay results showed that nine compounds did not vary significantly from the aerial parts and the whole plant for each batch, and was consistent with the fingerprint analysis, which confirmed the medicine parts alteration in Chinese Pharmacopoeia from the perspective of chemical components. PMID:25459936

La, Mingping; Zhang, Feng; Gao, Shouhong; Liu, Xiaowei; Wu, Zhijun; Sun, Lianna; Tao, Xia; Chen, Wansheng

2015-01-01

193

Identification and characterization of a new IgE-binding protein in mackerel ( Scomber japonicus) by MALDI-TOF-MS  

NASA Astrophysics Data System (ADS)

As fish is one source of the `big eight' food allergens, the prevalence of fish allergy has increased over the past few years. In order to better understand fish allergy, it is necessary to identify fish allergens. Based on the sera from fish-allergenic patients, a 28 kDa protein from local mackerel ( Scomber japonicus), which has not been reported as a fish allergen, was found to be reactive with most of the patients' sera. The 28 kDa protein was analyzed by MALDI-TOF-MS (Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry). Mascot search in NCBI database (Date: 08/07/2010) showed that the top protein matched, i.e. triosephosphate isomerase (TPI) from Xiphophorus maculatus and Poecilia reticulata, had a mowse (molecular weight search) score of 98. In addition, TPI from Epinephelus coioides also matched this mackerel protein with a mowse score of 96. Because TPI is considered as an allergen in other non-fish organisms, such as lychee, wheat, latex, archaeopotamobius ( Archaeopotamobius sibiriensis) and crangon ( Crangon crangon), we consider that it may also be an allergen in mackerel.

Wang, Bangping; Li, Zhenxing; Zheng, Lina; Liu, Yixuan; Lin, Hong

2011-03-01

194

Characterization and differentiation of high energy amine peroxides by direct analysis in real time TOF/MS  

NASA Astrophysics Data System (ADS)

Characterization of hexamethelene triperoxide diamine (HMTD), tetramethylene diperoxide dicarbamide (TMDD) and tetramethylene diperoxide acetamide (TMDA) has been carried out using Direct Analysis in Real Time/Time of Flight Mass Spectrometry (DART-TOF/MS). The study also centered in the detection of their precursors such as hexamine and formaldehyde. Analysis of the compounds by GC-MS was also conducted. HMTD shows a clear peak at 209 m/z that allowed its detection in standard solutions and lab made standards. TATP samples with deuterium enrichment are being analyzed to compare results that could differentiate from HMTD and similar substances. All samples were characterized by Raman and FT-IR to confirm the DART results. Some of the vibrations observed were in the ?(O-O), ?(N-C), ?(N-H), ?(C-O), ?(CH 3-C) and ?(C-O). Development methodology for trace detection was compared with GC/MS and HPLC-MS results previously presented for HMTD and TATP.

Peña-Quevedo, Alvaro J.; Cody, Robert; Mina-Camilde, Nairmen; Ramos, Mildred; Hernández-Rivera, Samuel P.

2007-04-01

195

Metabolome classification of commercial Hypericum perforatum (St. John's Wort) preparations via UPLC-qTOF-MS and chemometrics.  

PubMed

The growing interest in the efficacy of phytomedicines and herbal supplements but also the increase in legal requirements for safety and reliable contents of active principles drive the development of analytical methods for the quality control of complex, multicomponent mixtures as found in plant extracts of value for the pharmaceutical industry. Here, we describe an ultra-performance liquid chromatography method (UPLC) coupled with quadrupole time of flight mass spectrometry (qTOF-MS) measurements for the large scale analysis of H. perforatum plant material and its commercial preparations. Under optimized conditions, we were able to simultaneously quantify and identify 21 metabolites including 4 hyperforins, 3 catechins, 3 naphthodianthrones, 5 flavonoids, 3 fatty acids, and a phenolic acid. Principal component analysis (PCA) was used to ensure good analytical rigorousness and define both similarities and differences among Hypericum samples. A selection of batches from 9 commercially available H. perforatum products available on the German and Egyptian markets showed variable quality, particularly in hyperforins and fatty acid content. PCA analysis was able to discriminate between various preparations according to their global composition, including differentiation between various batches from the same supplier. To the best of our knowledge, this study provides the first approach utilizing UPLC-MS-based metabolic fingerprinting to reveal secondary metabolite compositional differences in Hypericum extract. PMID:22271082

Farag, Mohamed A; Wessjohann, Ludger A

2012-03-01

196

MALDI-TOF MS analysis of cellodextrins and xylo-oligosaccharides produced by hindgut homogenates of Reticulitermes santonensis.  

PubMed

Hindgut homogenates of the termite Reticulitermes santonensis were incubated with carboxymethyl cellulose (CMC), crystalline celluloses or xylan substrates. Hydrolysates were analyzed with matrix-assisted laser desorption/ionization coupled to time-of-flight mass spectrometry (MALDI-TOF MS). The method was first set up using acid hydrolysis analysis to characterize non-enzymatic profiles. Commercial enzymes of Trichoderma reesei or T. longibrachiatum were also tested to validate the enzymatic hydrolysis analysis. For CMC hydrolysis, data processing and visual display were optimized to obtain comprehensive profiles and allow rapid comparison and evaluation of enzymatic selectivity, according to the number of substituents of each hydrolysis product. Oligosaccharides with degrees of polymerization (DPs) ranging from three to 12 were measured from CMC and the enzymatic selectivity was demonstrated. Neutral and acidic xylo-oligosaccharides with DPs ranging from three to 11 were measured from xylan substrate. These results are of interest for lignocellulose biomass valorization and demonstrated the potential of termites and their symbiotic microbiota as a source of interesting enzymes for oligosaccharides production. PMID:24731986

Brasseur, Catherine; Bauwens, Julien; Tarayre, Cédric; Mattéotti, Christel; Thonart, Philippe; Destain, Jacqueline; Francis, Frédéric; Haubruge, Eric; Portetelle, Daniel; Vandenbol, Micheline; Focant, Jean-François; De Pauw, Edwin

2014-01-01

197

In cleanroom, sub-ppb real-time monitoring of volatile organic compounds using proton-transfer reaction/time of flight/mass spectrometry  

NASA Astrophysics Data System (ADS)

Refractory compounds such as Trimethylsilanol (TMS) and other organic compounds such as propylene glycol methyl ether acetate (PGMEA) used in the photolithography area of microelectronic cleanrooms have irreversible dramatic impact on optical lenses used on photolithography tools. There is a need for real-time, continuous measurements of organic contaminants in representative cleanroom environment especially in lithography zone. Such information is essential to properly evaluate the impact of organic contamination on optical lenses. In this study, a Proton-Transfer Reaction-Time-of-Flight Mass spectrometer (PTR-TOF-MS) was applied for real-time and continuous monitoring of fugitive organic contamination induced by the fabrication process. Three types of measurements were carried out using the PTR-TOF-MS in order to detect the volatile organic compounds (VOCs) next to the tools in the photolithography area and at the upstream and downstream of chemical filters used to purge the air in the cleanroom environment. A validation and verification of the results obtained with PTR-TOF-MS was performed by comparing these results with those obtained with an off-line technique that is Automated Thermal Desorber - Gas Chromatography - Mass Spectrometry (ATD-GC-MS) used as a reference analytical method. The emerged results from the PTR-TOF-MS analysis exhibited the temporal variation of the VOCs levels in the cleanroom environment during the fabrication process. While comparing the results emerging from the two techniques, a good agreement was found between the results obtained with PTR-TOF-MS and those obtained with ATD-GC-MS for the PGMEA, toluene and xylene. Regarding TMS, a significant difference was observed ascribed to the technical performance of both instruments.

Hayeck, Nathalie; Maillot, Philippe; Vitrani, Thomas; Pic, Nicolas; Wortham, Henri; Gligorovski, Sasho; Temime-Roussel, Brice; Mizzi, Aurélie; Poulet, Irène

2014-04-01

198

Simple analytical strategy for MALDI-TOF-MS and nanoUPLC-MS/MS: quantitating curcumin in food condiments and dietary supplements and screening of acrylamide-induced ROS protein indicators reduced by curcumin.  

PubMed

Curcumin is the major active ingredient of turmeric and is widely used as a preservative, flavouring and colouring agent. Curcumin is a potent substance with several functions, including antioxidant, antitumor, anti-inflammatory, antimicrobial, antiparasitic, antimutagenic, chemopreventive and chemotherapeutic activities. Matrix-assisted laser desorption/ionisation coupled with time-of-flight mass spectrometry (MALDI-TOF-MS) has been used to analyse various molecules (including natural antioxidants). This study established an expeditious method that couples MALDI-TOF-MS with a simple dilution method to quantify curcumin in food condiments and dietary supplements. The linear range of curcumin detection ranged from 1 to 100 ?g/mL. In further experiments, liver cells were treated with curcumin after exposure to acrylamide. Nano ultra performance liquid chromatographic system (nanoUPLC) coupled with tandem mass spectrometry (MS/MS) was used to evaluate the potential proteins and protein modifications induced by acrylamide. The results indicate that curcumin reduces the effects of reactive oxygen species induced by acrylamide. PMID:25529721

Huang, Yu-Shu; Hsieh, Tusty-Jiuan; Lu, Chi-Yu

2015-05-01

199

Characterization of the Lactobacillus casei group based on the profiling of ribosomal proteins coded in S10-spc-alpha operons as observed by MALDI-TOF MS.  

PubMed

The taxonomy of the members of the Lactobacillus casei group is complicated because of their phylogenetic similarity and controversial nomenclatural status. In this study, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) of ribosomal proteins coded in the S10-spc-alpha operon, termed S10-GERMS, was applied in order to classify 33 sample strains belonging to the L. casei group. A total of 14 types of ribosomal protein genes coded in the operon were first sequenced from four type strains of the L. casei group (L. casei JCM 1134(T), L. paracasei subsp. paracasei JCM 8130(T), L. paracasei subsp. tolerans JCM 1171(T), and L. rhamnosus JCM 1136(T)) together with L. casei JCM 11302, which is the former type strain of 'L. zeae'. The theoretical masses of the 14 types of ribosomal proteins used as biomarkers were classified into five types and compiled into a ribosomal protein database. The observed ribosomal proteins of each strain, identified by MALDI-TOF MS, were categorized into types based on their masses, summarized as ribosomal protein profiles, and they were used to construct a phylogenetic tree. The 33 sample strains, together with seven genome-sequenced strains, could be classified into four major clusters, which coincided precisely with the taxa of the (sub)species within the L. casei group. Three "ancient" strains, identified as L. acidophilus and L. casei, were correctly re-identified as L. paracasei subsp. paracasei by S10-GERMS. S10-GERMS would thus appear to be a powerful tool for phylogenetic characterization, with considerable potential for management of culture collections. PMID:23099260

Sato, Hiroaki; Torimura, Masaki; Kitahara, Maki; Ohkuma, Moriya; Hotta, Yudai; Tamura, Hiroto

2012-10-01

200

Differentiation in MALDI-TOF MS and FTIR spectra between two pathovars of Xanthomonas oryzae  

NASA Astrophysics Data System (ADS)

Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc) strains are closely related phenotypically and genetically, which make it difficult to differentiate between the two pathovars based on phenotypic and DNA-based methods. In this study, a fast and accurate method was developed based on the differences in MALDI-TOF MS and FTIR spectra between the two pathovars. MALDI-TOF MS analysis revealed that 9 and 10 peaks are specific to Xoo and Xoc, respectively, which can be used as biomarkers to identify and differentiate the two closely related pathovars. Furthermore, FTIR analysis showed that there is a significant difference in both the band frequencies and absorption intensity of various functional groups between the two pathovars. In particular, the 6 peaks at 3433, 2867, 1273, 1065, 983 and 951 cm-1 were specific to the Xoo strains, while one peak at 1572 cm-1 was specific to the Xoc strains. Overall, this study gives the first attempt to identify and differentiate the two pathovars of X. oryzae based on mass and FTIR spectra, which will be helpful for the early detection and prevention of the two rice diseases caused by both X. oryzae pathovars.

Ge, Mengyu; Li, Bin; Wang, Li; Tao, Zhongyun; Mao, Shengfeng; Wang, Yangli; Xie, Guanlin; Sun, Guochang

2014-12-01

201

Differentiation in MALDI-TOF MS and FTIR spectra between two pathovars of Xanthomonas oryzae.  

PubMed

Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc) strains are closely related phenotypically and genetically, which make it difficult to differentiate between the two pathovars based on phenotypic and DNA-based methods. In this study, a fast and accurate method was developed based on the differences in MALDI-TOF MS and FTIR spectra between the two pathovars. MALDI-TOF MS analysis revealed that 9 and 10 peaks are specific to Xoo and Xoc, respectively, which can be used as biomarkers to identify and differentiate the two closely related pathovars. Furthermore, FTIR analysis showed that there is a significant difference in both the band frequencies and absorption intensity of various functional groups between the two pathovars. In particular, the 6 peaks at 3433, 2867, 1273, 1065, 983 and 951cm(-1) were specific to the Xoo strains, while one peak at 1572cm(-1) was specific to the Xoc strains. Overall, this study gives the first attempt to identify and differentiate the two pathovars of X. oryzae based on mass and FTIR spectra, which will be helpful for the early detection and prevention of the two rice diseases caused by both X. oryzae pathovars. PMID:24996215

Ge, Mengyu; Li, Bin; Wang, Li; Tao, Zhongyun; Mao, Shengfeng; Wang, Yangli; Xie, Guanlin; Sun, Guochang

2014-12-10

202

[Rapid identification of six chemical constituents in Guizhi Fuling capsule by DART-Q-TOF-MS].  

PubMed

In order to establish a rapid method for identifying six constituents in Guizhi Fuling capsule, Q-TOF with DART ion source was used to perform the direct analysis of compounds in Guizhi Fuling capsule. The DART sampler delivery rate was 0.2 mm s(-1). The temperature of helium gas of DART was 450 degrees C. The capillary voltage was kept at 1 000 V. The temperature of the drying gas of Agilent 6538 Q-TOF MS was set at 350 degrees C. The flow rate of the drying gas of MS was set at 3.5 L x min(-1). The MS scan range was m/z 50-1 000. Based on accurate mass measurements and the elemental compositions of the product ions and fragmentation patterns of reference conpounds, six components, amygdalin, paeonol, paeoniflorin, cinnamic acids, gallic acid, benzoic acid were identified rapidly. The method can rapidly identify six chemical constituents in three batch of Guizhi Fuling capsule. The DART-Q-TOF-MS method is simple, rapid and specific and it can be used for rapid identification and characterization of compounds in traditional Chinese medicines. PMID:25775778

Wei, Zhang; Xue, Wang; Yan-jing-ping; Li, Yan-jing; Bi, Yu-an; Wang, Zhen-zhong; Xiao, Wei

2014-11-01

203

PTRwid: a new widget-tool for processing PTR-TOF-MS data  

NASA Astrophysics Data System (ADS)

PTRwid is a fast and user friendly tool that has been developed to process data from proton-transfer-reaction time-of-flight mass-spectrometers (PTR-TOF-MS) that use HTOF time-of-flight mass-spectrometers from Tofwerk AG (Switzerland). PTRwid is designed for a comprehensive evaluation of whole laboratory or field based studies. All processing runs autonomously and whole laboratory or field campaigns can, in principle, be processed with a few mouse clicks. Unique features of PTRwid include (i) an autonomous and accurate mass scale calibration, (ii) the computation of an "Unified Mass list" that - in addition to an uniform data structure - provides a robust method to determine the precision of attributed peak masses, and (iii) fast data analysis due to well considered choices in data processing.

Holzinger, R.

2015-02-01

204

UPLC\\/Q-TOF-MS\\/MS METHOD FOR EVALUATION OF MOXIFLOXACIN LOADED NANOPLEXES AS VEHICLES FOR OCULAR DRUG DELIVERY  

Microsoft Academic Search

A simple, sensitive and selective ultra performance liquid chromatographic (UPLC) method with quadrapole-time of flight-mass spectrometric (Q-TOF-MS\\/MS) detection was developed for the determination of moxifloxacin (moxi) in rabbit aqueous humor. After a simple protein-precipitation by acetonitrile, the post-treatment samples were separated on a UPLC Bridged Ethyl Hybrid (BEH) C-18 column with 0.1% formic acid in water as a mobile phase

Musarrat H Warsi; Gaurav K Jain; Shadab A Pathan; Mohammad Anwar; Neha Mallick; Niyaz Ahmad; Sushama Talegaonkar; Farhan J Ahmad; Roop K Khar

2012-01-01

205

Discrimination of Escherichia coli O157, O26 and O111 from Other Serovars by MALDI-TOF MS Based on the S10-GERMS Method  

PubMed Central

Enterohemorrhagic Escherichia coli (EHEC), causes a potentially life-threatening infection in humans worldwide. Serovar O157:H7, and to a lesser extent serovars O26 and O111, are the most commonly reported EHEC serovars responsible for a large number of outbreaks. We have established a rapid discrimination method for E. coli serovars O157, O26 and O111 from other E. coli serovars, based on the pattern matching of mass spectrometry (MS) differences and the presence/absence of biomarker proteins detected in matrix-assisted laser desorption/ionization time-of-flight MS (MALDI-TOF MS). Three biomarkers, ribosomal proteins S15 and L25, and acid stress chaperone HdeB, with MS m/z peaks at 10138.6/10166.6, 10676.4/10694.4 and 9066.2, respectively, were identified as effective biomarkers for O157 discrimination. To distinguish serovars O26 and O111 from the others, DNA-binding protein H-NS, with an MS peak at m/z 15409.4/15425.4 was identified. Sequence analysis of the O157 biomarkers revealed that amino acid changes: Q80R in S15, M50I in L25 and one mutation within the start codon ATG to ATA in the encoded HdeB protein, contributed to the specific peak pattern in O157. We demonstrated semi-automated pattern matching using these biomarkers and successfully discriminated total 57 O157 strains, 20 O26 strains and 6 O111 strains with 100% reliability by conventional MALDI-TOF MS analysis, regardless of the sample conditions. Our simple strategy, based on the S10-spc-alpha operon gene-encoded ribosomal protein mass spectrum (S10-GERMS) method, therefore allows for the rapid and reliable detection of this pathogen and may prove to be an invaluable tool both clinically and in the food industry. PMID:25411793

Ojima-Kato, Teruyo; Yamamoto, Naomi; Suzuki, Mayumi; Fukunaga, Tomohiro; Tamura, Hiroto

2014-01-01

206

Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Fast and Reliable Identification of Clinical Yeast Isolates?  

PubMed Central

The clinical impact of severe infections with yeasts and yeast-like fungi has increased, especially in immunocompromised hosts. In recent years, new antifungal agents with different and partially species-specific activity patterns have become available. Therefore, rapid and reliable species identification is essential for antifungal treatment; however, conventional biochemical methods are time-consuming and require considerable expertise. We evaluated matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the rapid routine identification of clinical yeast isolates. A total of 18 type collection strains and 267 recent clinical isolates of Candida (n = 250), Cryptococcus, Saccharomyces, Trichosporon, Geotrichum, Pichia, and Blastoschizomyces spp. were identified by MALDI-TOF MS. The results were compared with those obtained by conventional phenotyping and biochemical tests, including the API ID 32C system (bioMérieux, Nürtingen, Germany). Starting with cells from single colonies, accurate species identification by MALDI-TOF MS was achieved for 247 of the clinical isolates (92.5%). The remaining 20 isolates required complementation of the reference database with spectra for the appropriate reference strains which were obtained from type culture collections or identified by 26S rRNA gene sequencing. The absence of a suitable reference strain from the MALDI-TOF MS database was clearly indicated by log(score) values too low for the respective clinical isolates; i.e., no false-positive identifications occurred. After complementation of the database, all isolates were unambiguously identified. The established API ID 32C biochemical diagnostic system identified 244 isolates in the first round. Overall, MALDI-TOF MS proved a most rapid and reliable tool for the identification of yeasts and yeast-like fungi, with the method providing a combination of the lowest expenditure of consumables, easy interpretation of results, and a fast turnaround time. PMID:19571014

Marklein, G.; Josten, M.; Klanke, U.; Müller, E.; Horré, R.; Maier, T.; Wenzel, T.; Kostrzewa, M.; Bierbaum, G.; Hoerauf, A.; Sahl, H.-G.

2009-01-01

207

Identification of clinical coagulase-negative staphylococci, isolated in microbiology laboratories, by matrix-assisted laser desorption/ionization-time of flight mass spectrometry and two automated systems.  

PubMed

A study was performed to compare matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS), linked to a recently engineered microbial identification database, and two rapid identification (ID) automated systems, BD Phoenix (Becton Dickinson Diagnostic Systems, France) and VITEK-2 (bioMérieux, Marcy L'Etoile, France), for the ID of coagulase-negative staphylococci (CoNS). Two hundred and thirty-four clinical isolates of CoNS representing 20 species were analyzed. All CoNS isolates were characterized by sodA gene sequencing, allowing interpretation of the ID results obtained using the respective database of each apparatus. Overall correct ID results were obtained in 93.2%, 75.6% and 75.2% of the cases with the MALDI-TOF-MS, Phoenix and VITEK-2 systems, respectively. Mis-ID and absence of results occurred in 1.7% and 5.1% of the cases with MALDI-TOF-MS, in 23.1% and 1.3% with the Phoenix, and in 13.7% and 0.9% with the VITEK-2 systems, respectively. In addition, with the latter automate, 10.3% of the IDs were proposed with remote possibility. When excluding the CoNS species not included in the databases of at least one of the three systems, the final percentage of correct results, Mis-ID and absence of ID were 97.4%, 1.3% and 1.3% with MALDI-TOF-MS, 79%, 21% and 0% with the Phoenix, and 78.6%, 10.3% and 0.9% with the VITEK-2 system, respectively. The present study demonstrates the robustness and high sensitivity of our microbial identification database used with MALDI-TOF-MS technology. This approach represents a powerful tool for the fast ID of clinical CoNS isolates. PMID:19732092

Dupont, C; Sivadon-Tardy, V; Bille, E; Dauphin, B; Beretti, J L; Alvarez, A S; Degand, N; Ferroni, A; Rottman, M; Herrmann, J L; Nassif, X; Ronco, E; Carbonnelle, E

2010-07-01

208

High-Throughput Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry as an Alternative Approach to Monitoring Drug Resistance of Hepatitis B Virus  

PubMed Central

Long-term antiviral therapy of chronic hepatitis B virus (HBV) infection can lead to the selection of drug-resistant HBV variants and treatment failure. Moreover, these HBV strains are possibly present in treatment-naive patients. Currently available assays for the detection of HBV drug resistance can identify mutants that constitute ?5% of the viral population. Furthermore, drug-resistant HBV variants can be detected when a viral load is >104 copies/ml (1,718 IU/ml). The aim of this study was to compare matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) and multitemperature single-strand conformation polymorphism (MSSCP) with commercially available assays for the detection of drug-resistant HBV strains. HBV DNA was extracted from 87 serum samples acquired from 45 chronic hepatitis B (CHB) patients. The 37 selected HBV variants were analyzed in 4 separate primer extension reactions on the MALDI-TOF MS. Moreover, MSSCP for identifying drug-resistant HBV YMDD variants was developed and turned out to be more sensitive than INNOLiPA HBV DR and direct sequencing. MALDI-TOF MS had the capability to detect mutant strains within a mixed viral population occurring with an allelic frequency of approximately 1% (with a specific value of ?102 copies/ml, also expressed as ?17.18 IU/ml). In our study, MSSCP detected 98% of the HBV YMDD variants among strains detected by the MALDI-TOF MS assay. The routine tests revealed results of 40% and 11%, respectively, for INNOLiPA and direct sequencing. The commonly available HBV tests are less sensitive than MALDI-TOF MS in the detection of HBV-resistant variants, including quasispecies. PMID:24068014

Rybicka, Magda; Dreczewski, Marcin; Smiatacz, Tomasz

2014-01-01

209

Evaluation of the Bruker Biotyper and VITEK MS MALDI-TOF MS systems for the identification of unusual and/or difficult-to-identify microorganisms isolated from clinical specimens.  

PubMed

The purpose of this investigation was to evaluate the analytical performance characteristics of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of unusual organisms. We evaluated the accuracy of two MALDI-TOF MS systems, bioMérieux VITEK MS (database v2.0) and Bruker Biotyper (software version 3.0), for the identification of the most difficult and/or unusual microorganisms isolated from clinical specimens. Our study included 174 bacterial isolates recovered from clinical cultures at Barnes-Jewish Hospital, St. Louis, MO, from 2009 to 2013, representing 50 genera and 52 species. MS identifications were compared to the identification reported by the reference laboratory. Discrepancies were resolved using molecular methods, including 16S rRNA gene sequencing and additional molecular methods. When performed, molecular methods were considered the gold standard. Of the 168 isolates resolved to the genus level, VITEK MS identified 145 (86.3 %), and of the 114 isolates resolved to the species level, 97 (85.1 %) were correctly identified. Bruker Biotyper identified 155 (92.3 %) of 168 isolates to the genus level and 97 (85.1 %) of 114 isolates to the species level. VITEK MS and Bruker Biotyper provided no identification for 17 (10.1 %) and 12 (7.1 %) organisms, respectively, and misidentified six (3.6 %) and one (0.6 %) isolate, respectively. Six isolates (3.6 %) were not resolvable to the genus level and were excluded from data analysis due to the lack of a gold standard for comparison. There was no significant difference in the number of organisms identified to the genus level, species level, unidentified, or misidentified by the two MALDI-TOF MS systems (p = 0.11, 1.0, 0.44, and 0.12, respectively). PMID:24962194

McElvania TeKippe, E; Burnham, C-A D

2014-12-01

210

Analysis of new synthetic drugs by ion mobility time-of-flight mass spectrometry.  

PubMed

Characteristic ion mobility mass spectrometry data, reduced mobility, and limits of detection (signal-to-noise ratio = 3) were determined for six synthetic drugs and cocaine by ion mobility time-of-flight mass spectrometry (IM-TOF-MS) with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). The studied synthetic illicit drugs recently appeared on the recreational drug market as designer drugs and were methylone, 4-MEC (4'-methylethcathinone), 3,4-MDPV (3,4-methylenedioxypyrovalerone), JWH-210 [4-ethylnaphthalen-1-yl-(1-pentylindol-3-yl)methanone], JWH-250 [2-(2-methoxyphenyl)-1-(1-pentyl-1H-indol-3-yl)ethanone], and JWH-203 [1-pentyl-3-(2'-chlorophenylacetyl) indole]. Absolute reduced mobilities in nitrogen were 1.35, 1.28, 1.41, 1.30, 1.18, 0.98, 1.09, and 1.07 cm2V(-1)s(-1), for methylone [M-H]+, methylone [M+H]+, 4-MEC [M-H]+, 4-MEC [M+H]+, 3,4-MDPV [M+H]+, JWH-210 [M+H]+, JWH-250 [M+H]+, and JWH-203 [M+H]+, respectively. Selected illicit drugs are easily identified by IM-TOF-MS during a 100s analysis. Relative Limits of detection ranged from 4 to 400 nM are demonstrated for these compounds. Such relative limits of detection correspond to 14 pg to 2 ng absolute limits of detection. Better detection limits are obtained in APCI mode for all the illicit drugs except cocaine. ESI mode was found to be preferable for the IM-TOF-MS detection of cocaine at trace levels. A single sample analysis is completed in an order of magnitude less time than that for conventional liquid chromatography/mass spectrometry approach. The application allows one to consider IM-TOF-MS as a good candidate for a method to determine quickly the recently surfaced designer drugs marketed on the internet as "bath salts," "spice," and "herbal blends". PMID:24895779

Sysoev, Alexey A; Poteshin, Sergey S; Chernyshev, Denis M; Karpov, Alexander V; Tuzkov, Yuriy B; Kyzmin, Vyacheslav V; Sysoev, Alexander A

2014-01-01

211

Identification of lipopeptide isoforms by MALDI-TOF-MS/MS based on the simultaneous purification of iturin, fengycin, and surfactin by RP-HPLC.  

PubMed

A three-stage linear gradient strategy using reverse-phase high-performance liquid chromatography (HPLC) was optimized for rapid, high-quality, and simultaneous purification of the lipopeptide isoforms of iturin, fengycin, and surfactin, which may differ in composition by only a single amino acid and/or the fatty acid residue. Matrix-assisted laser desorption ionization time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS) was applied to detect the lipopeptides harvested from each reversed-phase HPLC peak. Amino acid analysis based on phenyl isothiocyanate derivatization was further used for confirmation of the amino acid species and molar ratio in a certain HPLC fraction. By this MALDI-TOF-MS/MS coupled with amino acid analysis, it was revealed that iturin at m/z 1,043 consists of a circular Asn-Tyr-Asn-Gln-Pro-Asn-Ser peptide and C14 ?-OH fatty acid. Surfactin homologs from Bacillus subtilis THY-7 at m/z 1,030, 1,044, 1,058, and 1,072 possess a circular Glu-Leu-Leu-Val-Asp-Leu-Leu peptide and the ?-OH fatty acid with a different length (C13-C16). Fengycin species at m/z 1,463 and 1,477 are homologs possessing the circular peptide Glu-Orn-Tyr-Thr-Glu-Ala-Pro-Gln-Tyr-Ile linked to a C16 or C17 ?-OH fatty acid, whereas fengycin at m/z 1,505 contains a Glu-Orn-Tyr-Thr-Glu-Val-Pro-Gln-Tyr-Ile sequence with a Val instead of Ala at position 6. The method developed in this work provided an efficient approach for characterization of diverse lipopeptide isoforms from the iturin, fengycin, and surfactin families. PMID:25662934

Yang, Huan; Li, Xu; Li, Xue; Yu, Huimin; Shen, Zhongyao

2015-03-01

212

Multi-element analysis of milk by ICP-oa-TOF-MS after precipitation of calcium and proteins by oxalic and nitric acid.  

PubMed

In this work a simple technique employing oxalic and nitric acid to cow's milk samples prior to analysis by inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry (ICP-oa-TOF-MS) was introduced. After the precipitation of calcium and proteins via oxalic and nitric acid, respectively, the resulting liquid phase was aspirated with a concentric glass nebulizer for ICP-TOF-MS determination of trace elements. Precipitation of proteins is essential for better separation of solid and liquid phase of modified samples. Separation of calcium as a precipitated non-soluble oxalate enables the elimination of spectral interferences originating from different calcium containing species like (40)Ca(35)Cl(+), (40)Ca(37)Cl(+), (43)Ca(16)O(+), (40)Ca(18)O(+), (44)Ca(16)O(+), (43)Ca(16)O(1)H(+) onto the determination of As, Se, Co and Ni whose assay is more difficult when using conventional quadrupole instruments. High detection capability is further an advantage as the approach enables the analysis without dilution. The methodology may serve, in addition, for a fast and sensitive determination of some other elements. After that, direct, reliable and simultaneous determination of 16 elements (Li, Be, B, V, Cr, Mn, Ni, Co, Ga, As, Se, Mo, Sn, Sb, Cs, Tl) at trace and ultra-trace levels in milk can be performed under optimum instrumental conditions and by using Rh as an internal standard. Accuracy and precision was assessed by measuring NCS ZC73015 milk powder control standard, yielding results in agreement with certified values and RSD <10%. The accuracy was also checked by comparison of the results of the proposed method with those found by a method based on a microwave-assisted digestion of real samples. PMID:23598096

Husáková, Lenka; Urbanová, Iva; Šrámková, Jitka; Kone?ná, Michaela; Bohuslavová, Jana

2013-03-15

213

The influence of incubation time, sample preparation and exposure to oxygen on the quality of the MALDI-TOF MS spectrum of anaerobic bacteria.  

PubMed

With matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), bacteria can be identified quickly and reliably. This accounts especially for anaerobic bacteria. Because growth rate and oxygen sensitivity differ among anaerobic bacteria, we aimed to study the influence of incubation time, exposure to oxygen and sample preparation on the quality of the spectrum using the Bruker system. Also, reproducibility and inter-examiner variability were determined. Twenty-six anaerobic species, representing 17 genera, were selected based on gram-stain characteristics, growth rate and colony morphology. Inter-examiner variation showed that experience in the preparation of the targets can be a significant variable. The influence of incubation time was determined between 24 and 96 h of incubation. Reliable species identification was obtained after 48 h of incubation for gram-negative anaerobes and after 72 h for gram-positive anaerobes. Exposure of the cultures to oxygen did not influence the results of the MALDI-TOF MS identifications of all tested gram-positive species. Fusobacterium necrophorum and Prevotella intermedia could not be identified after >24 h and 48 h of exposure to oxygen, respectively. Other tested gram-negative bacteria could be identified after 48 h of exposure to oxygen. Most of the tested species could be identified using the direct spotting method. Bifidobacterium longum and Finegoldia magna needed on-target extraction with 70% formic acid in order to obtain reliable species identification and Peptoniphilus ivorii a full extraction. Spectrum quality was influenced by the amount of bacteria spotted on the target, the homogeneity of the smear and the experience of the examiner. PMID:25039504

Veloo, A C M; Elgersma, P E; Friedrich, A W; Nagy, E; van Winkelhoff, A J

2014-12-01

214

Comparison of the Accuracy of Two Conventional Phenotypic Methods and Two MALDI-TOF MS Systems with That of DNA Sequencing Analysis for Correctly Identifying Clinically Encountered Yeasts  

PubMed Central

We assessed the accuracy of species-level identification of two commercially available matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) systems (Bruker Biotyper and Vitek MS) and two conventional phenotypic methods (Phoenix 100 YBC and Vitek 2 Yeast ID) with that of rDNA gene sequencing analysis among 200 clinical isolates of commonly encountered yeasts. The correct identification rates of the 200 yeast isolates to species or complex (Candida parapsilosis complex, C. guilliermondii complex and C. rugosa complex) levels by the Bruker Biotyper, Vitek MS (using in vitro devices [IVD] database), Phoenix 100 YBC and Vitek 2 Yeast ID (Sabouraud's dextrose agar) systems were 92.5%, 79.5%, 89%, and 74%, respectively. An additional 72 isolates of C. parapsilosis complex and 18 from the above 200 isolates (30 in each of C. parapsilosis, C. metapsilosis, and C. orthopsilosis) were also evaluated separately. Bruker Biotyper system could accurately identify all C. parapsilosis complex to species level. Using Vitek 2 MS (IVD) system, all C. parapsilosis but none of C. metapsilosis, or C. orthopsilosis could be accurately identified. Among the 89 yeasts misidentified by the Vitek 2 MS (IVD) system, 39 (43.8%), including 27 C. orthopsilosis isolates, could be correctly identified Using the Vitek MS Plus SARAMIS database for research use only. This resulted in an increase in the rate of correct identification of all yeast isolates (87.5%) by Vitek 2 MS. The two species in C. guilliermondii complex (C. guilliermondii and C. fermentati) isolates were correctly identified by cluster analysis of spectra generated by the Bruker Biotyper system. Based on the results obtained in the current study, MALDI-TOF MS systems present a promising alternative for the routine identification of yeast species, including clinically commonly and rarely encountered yeast species and several species belonging to C. parapsilosis complex, C. guilliermondii complex, and C. rugosa complex. PMID:25330370

Chao, Qiao-Ting; Lee, Tai-Fen; Teng, Shih-Hua; Peng, Li-Yun; Chen, Ping-Hung; Teng, Lee-Jene; Hsueh, Po-Ren

2014-01-01

215

MALDI-TOF MS of Trichoderma: A model system for the identification of microfungi  

Technology Transfer Automated Retrieval System (TEKTRAN)

This investigation aimed to assess whether MALDI-TOF MS analysis of proteomics could be applied to the study of Trichoderma, a fungal genus selected because it includes many species and is phylogenetically well defined. We also investigated whether MALDI-TOF MS analysis of proteomics would reveal ap...

216

Quantitative matrix-assisted laser desorption ionization-time of flight mass spectrometry for rapid resistance detection.  

PubMed

Antibiotic resistance in Gram-negative microorganisms is an increasing health care problem. The rapid detection of such resistance is crucial for starting an early specific therapy and to enable initiation of the required hygiene measures. With continued emphasis on reducing the cost of laboratory testing, only economical/low-cost approaches have a chance of being implemented. During recent years, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been developed to be a standard method in microbiology laboratories for the rapid and cost-efficient identification of microorganisms. Extending the usage of MALDI-TOF MS in the clinical microbiology laboratory to the area of resistance testing is an attractive option. Quantitative MALDI-TOF MS using an internal standard facilitates the measurement of the quantity of peptides and small proteins within a spectrum. These quantities correlate to the number of microorganisms and therefore to the growth of a microorganism. The comparison of growth in the presence or absence of an antibiotic allows for analysis of the susceptibility behavior of a strain. Here, we describe a novel method and its application in the analysis of 108 Klebsiella sp. isolates. After 1 h of incubation at a meropenem concentration of 8 ?g/ml, a sensitivity of 97.3% and a specificity of 93.5% were achieved (compared to Etest results). PMID:25232164

Lange, Christoph; Schubert, Sören; Jung, Jette; Kostrzewa, Markus; Sparbier, Katrin

2014-12-01

217

Species identification of strains belonging to genus Citrobacter using the biochemical method and MALDI-TOF mass spectrometry.  

PubMed

Strains of genus Citrobacter (152 isolates from 1950 to 1988 deposited in the Czech National Collection of Type Cultures, Prague) were re-classified using biological and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) methods. One-hundred thirty-six strains (ca. 90 %) were identified to the species level using the biological method with evaluation by Farmer matrix. MALDI-TOF MS exhibited better identification capability, the data being more compact; the method was unambiguously successful in typing 145 (95 %) strains. Comparison of the results of identification by the two methods revealed differences (for 12 samples) in identified species which, considering all biochemical and/or MS characteristics, could be attributed to the natural variability of strains and close relation of the misidentified species (all of them belonged to the Citrobacter freundii complex). Taking into account all the above data, both methods can be considered reliable; however, the MALDI-TOF MS exhibits higher accuracy, efficiency, and rapidity. PMID:25113540

Kolínská, Renáta; Span?lová, Petra; D?evínek, Michal; Hrabák, Jaroslav; Zemli?ková, Helena

2015-01-01

218

Analysis of modified polyamide 6.6 using coupled liquid chromatography and MALDI-TOF-mass spectrometry  

NASA Astrophysics Data System (ADS)

A new approach of analysis of polyamide 6.6 using the principle of coupling polymer liquid chromatography to matrix assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) is presented. In contrast to the known technique of two-dimensional chromatography, MALDI-TOF-MS was applied in the 2nd chromatographic dimension. According to the synthesis of polyamide 6.6 various species with different end groups are expected. Due to the capping of the end groups during the synthesis, either performed by the addition of mono-functional amines or acids, additional structures are formed and found. Although the resolution of chromatography applied for separation was poor in comparison to the broad variety of expected species, a complete identification of those components was achieved applying the MALDI-TOF-MS technique. The results were presented in a two-dimensional plot, which can be used as a fingerprint method for the analysis of polyamide 6.6.

Weidner, Steffen M.; Just, Ulrich; Wittke, Wolfgang; Rittig, Frank; Gruber, Freddy; Friedrich, Joerg F.

2004-11-01

219

Non-visible print set-off of photoinitiators in food packaging: detection by ambient ionisation mass spectrometry.  

PubMed

Direct analysis in real time coupled to time-of-flight mass spectrometry (DART/TOF-MS) was used to detect the non-visible set-off of photoinitiators on the food contact surface of three different packages. The samples were intentionally under-cured to provoke set-off. Twelve commercially available photoinitiators were included in the ink formulations including ?-amino-, morpholino, and ?-hydroxy benzophenones, thioxanthones, aryl-phosphine oxide and three polymeric versions of these. Major colours of the packages' prints were analysed, as well as the specific areas of the inner surface in contact with them. Larger quantities of photoinitiators were detected on the food contact areas in contact with the darker colours of the images. Speed-cure 7005 and 4-phenylbenzophenone were the compounds most susceptible to set-off in each of the samples by DART response. An identification protocol for unknown set-off compounds was tested, resulting in the set-off detection of diethylene glycol ethers, erucamide and acrylates, and confirmed by solvent extraction GC-MS analysis. Finally, DART/TOF-MS was scanned across transects of the food contact side of packages to map the presence of photoinitiators. Higher photoinitiator signals were observed in patterns corresponding to the printed image, suggesting DART/TOF-MS might "image" print set-off. PMID:23421479

Bentayeb, K; Ackerman, L K; Lord, T; Begley, T H

2013-01-01

220

A novel method to differentiate bovine and porcine gelatins in food products: nanoUPLC-ESI-Q-TOF-MS(E) based data independent acquisition technique to detect marker peptides in gelatin.  

PubMed

We presented a novel nanoUPLC-MS(E) workflow method that has potential to identify origin of gelatin in some dairy products; yoghurt, cheese and ice cream. In this study, the method was performed in two steps. In the first step, gelatin was extracted from these products before the MS-sample preparation. In the second step, tryptic gelatin peptides were separated and analyzed with ultra-performance liquid chromatography and electrospray ionization quadrupole time-of-flight mass spectrometry (nanoUPLC-ESI-q-TOF-MS(E)). The novelty of this setup was that it functioned in a data independent acquisition mode and that alternate low and elevated collision energy was applied to acquire precursor and product ion information. This enabled accurate mass acquisition on the peptide level to identify the gelatin peptides. The marker peptides specific for porcine and bovine could be successfully detected in the gelatin added to the dairy products analyzed, revealing that the detection of marker peptides in the digested gelatin samples using nanoUPLC-ESI-q-TOF-MS(E) could be an effective method to differentiate porcine and bovine gelatin in the dairy products. PMID:23870980

Yilmaz, Mustafa Tahsin; Kesmen, Zulal; Baykal, Betul; Sagdic, Osman; Kulen, Oktay; Kacar, Omer; Yetim, Hasan; Baykal, Ahmet Tarik

2013-12-01

221

MALDI-TOF mass spectrometry for rapid identification of clinical fungal isolates based on ribosomal protein biomarkers.  

PubMed

This study aimed to evaluate the identification of clinical fungal isolates (yeast and molds) by protein profiling using Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS). A total of 125 clinical fungal culture isolates (yeast and filamentous fungi) were collected. The test set included 88 yeast isolates (Candida albicans, Candida glabrata, Candida guilliermondii, Candida kefyr, Candida krusei, Candida parapsilosis, Candida rugosa, Candida tropicalis and Cryptococcus neoformans) and 37 isolates of molds (Alternaria spp., Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Cunninghamella spp., Histoplasma capsulatum, Microsporum gypseum, Microsporum nanum, Rhizomucor spp. and Trichophyton spp.). The correlation between MALDI TOF MS and conventional identification for all these 125 fungal isolates included in the study was 87.2% at the species level and 90.4% at the genus level. MALDI TOF MS results revealed that the correlation in yeast (n=88) identification was 100% both at the genus and species levels whereas, the correlation in mold (n=37) identification was more heterogeneous i.e. 10.81% isolates had correct identification up to the genus level, 56.7% isolates had correct identification both at the genus and species levels, whereas 32.42% isolates were deemed Not Reliable Identification (NRI). But, with the modification in sample preparation protocol for molds, there was a significant improvement in identification. 86.4% isolates had correct identification till the genus and species levels whereas, only 2.7% isolates had Not Reliable Identification. In conclusion, this study demonstrates that MALDI-TOF MS could be a possible alternative to conventional techniques both for the identification and differentiation of clinical fungal isolates. However, the main limitation of this technique is that MS identification could be more precise only if the reference spectrum of the fungal species is available in the database. PMID:25541362

Panda, Ashutosh; Ghosh, Anup K; Mirdha, Bijay R; Xess, Immaculata; Paul, Saikat; Samantaray, Jyotish C; Srinivasan, Alagiri; Khalil, Shehla; Rastogi, Neha; Dabas, Yubhisha

2015-02-01

222

Rapid discrimination of Bifidobacterium animalis subspecies by matrix-assisted laser desorption ionization-time of flight mass spectrometry.  

PubMed

Currently, the species Bifidobacterium animalis consists of two subspecies, B. animalis subsp. lactis and B. animalis subsp. animalis. Among these two subspecies, B. animalis subsp. lactis is especially important because it is widely used in the manufacture of probiotic dairy products. The application of these microbes in the food industry demands fast, accurate and low cost methods to differentiate between species and strains. Although various genotypic methods have been employed to discriminate between these two subspecies, they are not easily adapted for rapid identification in the industry. The purpose of this study was to evaluate the use of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) to differentiate between the two subspecies of B. animalis, and for discrimination at strain level. We identified twenty-three strains of B. animalis at subspecies and strain level by genotypic methods and by proteomics using MALDI-TOF MS. The proteomics identification by MALDI-TOF was nearly identical to that obtained by genotypic identification using comparison of tuf and atpD gene sequences, and single-nucleotide polymorphisms (SNPs), insertions, and deletions (INDELs). We identified four protein markers, L1, L2, A1, and A2, which are useful for discriminating between both subspecies. Proteomics identification using MALDI-TOF MS was therefore an accurate method for discriminating and identifying these bacteria. Given the speed in which this method is achieved (~20 min including sample preparation), MALDI-TOF MS is promising as a tool for rapid discrimination of starter cultures and probiotics. PMID:22365357

Ruiz-Moyano, Santiago; Tao, Nannan; Underwood, Mark A; Mills, David A

2012-06-01

223

False Results Caused by Solvent Impurity in Tetrahydrofuran for MALDI TOF MS Analysis of Amines  

NASA Astrophysics Data System (ADS)

Tetrahydrofuran (THF) is one of the most frequently used solvents in the MALDI TOF MS analysis of synthetic compounds. However, it should be used with caution because a trace amount of 4-hydroxybutanal (HBA) might be generated and accumulated in THF during storage. Since only a tiny amount of analytes is required in MALDI MS measurements, a trace amount of HBA might have a significant effect on the MS results. It was found that HBA will quickly react with primary and secondary amino compounds, leading to false results about the sample composition with an extra series of ions with additional mass of 70 Da in between. The formation of HBA can be inhibited by butylated hydroxytoluene (BHT) antioxidant. Therefore, when THF is required as the solvent for sample preparation, it is strongly recommended to use a BHT-stabilized one, at least for the analysis of compounds with amino groups.

Lou, Xianwen; Leenders, Christianus M. A.; van Onzen, Arthur H. A. M.; Bovee, Ralf A. A.; van Dongen, Joost L. J.; Vekemans, Jef A. J. M.; Meijer, E. W.

2013-11-01

224

Two-step Laser Time-of-Flight Mass Spectrometry to Elucidate Organic Diversity in Planetary Surface Materials.  

NASA Technical Reports Server (NTRS)

Laser desorption/ionization time-of-flight mass spectrometry (LD-TOF-MS) holds promise to be a low-mass, compact in situ analytical capability for future landed missions to planetary surfaces. The ability to analyze a solid sample for both mineralogical and preserved organic content with laser ionization could be compelling as part of a scientific mission pay-load that must be prepared for unanticipated discoveries. Targeted missions for this instrument capability include Mars, Europa, Enceladus, and small icy bodies, such as asteroids and comets.

Getty, Stephanie A.; Brinckerhoff, William B.; Cornish, Timothy; Li, Xiang; Floyd, Melissa; Arevalo, Ricardo Jr.; Cook, Jamie Elsila; Callahan, Michael P.

2013-01-01

225

What is Mass Spectrometry?  

NSDL National Science Digital Library

This site from the American Society for Mass Spectrometry includes information about what mass spectometry is and how it is used. It has many useful figures and references to other materials. The material answers questions such as "What is mass spectrometry and what can it do for you?"

Chiu, Chia M.

226

Army medical laboratory telemedicine: role of mass spectrometry in telediagnosis for chemical and biological defense.  

PubMed

An army medical field laboratory presently has the capability of performing standard protocols developed at the US Army Medical Research Institute of Chemical Defense for verification of nerve agent or sulfur mustard exposure. The protocols analyze hydrolysis products of chemical warfare agents using gas chromatography/mass spectrometry. Additionally, chemical warfare agents can produce alkylated or phosphorylated proteins following human exposure that have long biological half-lives and can be used as diagnostic biomarkers of chemical agent exposure. An analytical technique known as matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS) currently is being examined for its potential to analyze these biomarkers. The technique is capable of detecting large biomolecules and modifications made to them. Its fast analysis time makes MALDI-TOF/MS technology suitable for screening casualties from chemical or biological attacks. Basic operation requires minimal training and the instrument has the potential to become field-portable. The limitation of the technique is that the generated data may require considerable expertise from knowledgeable personnel for consultation to ensure correct interpretation. The interaction between research scientists and field personnel in the acquisition of data and its interpretation via advanced digital telecommunication technologies can enhance rapid diagnosis and subsequently improve patient care in remote areas. PMID:11920918

Smith, J R; Shih, M L; Price, E O; Platoff, G E; Schlager, J J

2001-12-01

227

Analysis of Whole Bacterial Cells by Flow Field-Flow Fractionation and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry  

SciTech Connect

The purpose of this study is to develop a novel bacterial analysis method by coupling the flow field-flow fractionation (flow FFF) separation technique with detection by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The composition of carrier liquid used for flow FFF was selected based on retention of bacterial cells and compatibility with the MALDI process. The feasibility of coupling flow FFF and MALDI-TOF MS was demonstrated for P. putida and E. coli. Fractions of the whole cells were collected after separation by FFF and further analyzed by MALDI-MS. Each fraction, collected over different time intervals, corresponded to different sizes and possibly different growth stages of bacteria. The bacterial analysis by flow FFF/MALDI-TOF MS was completed within 1 hour with only preliminary optimization of the process.

Lee, Hookeun; Williams, Kim R.; Wahl, Karen L.; Valentine, Nancy B.

2003-06-01

228

Identification of Anaerobic Bacteria by Bruker Biotyper Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry with On-Plate Formic Acid Preparation  

PubMed Central

Identification of anaerobic bacteria using phenotypic methods is often time-consuming; methods such as 16S rRNA gene sequencing are costly and may not be readily available. We evaluated 253 clinical isolates of anaerobic bacteria using the Bruker MALDI Biotyper (Bruker Daltonics, Billerica, MA) matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) system with a user-supplemented database and an on-plate formic acid-based preparation method and compared results to those of conventional identification using biochemical testing or 16S rRNA gene sequencing. A total of 179 (70.8%) and 232 (91.7%) isolates were correctly identified to the species and genus levels, respectively, using manufacturer-recommended score cutoffs. MALDI-TOF MS offers a rapid, inexpensive method for identification of anaerobic bacteria. PMID:23254126

Schmitt, Bryan H.; Cunningham, Scott A.; Dailey, Aaron L.; Gustafson, Daniel R.

2013-01-01

229

The Use of MALDI-TOF Mass Spectrometry, Ribotyping and Phenotypic Tests to Identify Lactic Acid Bacteria from Fermented Cereal Foods in Abidjan (Côte d’Ivoire)  

PubMed Central

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) protein analysis, automated ribotyping, and phenotypic tests (e.g., cell morphology, gas production from glucose, growth and acid production on homofermemtative-heterofermentative differential (HHD) agar medium, sugar fermentation patterns) were used to identify 23 lactic acid bacteria (LAB) isolated from fermented cereal foods available in Abidjan, Côte d’Ivoire. Pediococcus acidilactici (56.5%), Lactobacillus fermentum (30.4%), L. salivarius (4.3%), P. pentosaceus (4.3%) and L. plantarum subsp. plantarum (4.3%) were the species and subspecies identified. Protein based identification was confirmed by automated ribotyping for selected isolates and was similar to that provided by the phenotypic characterization. MALDI-TOF MS protein analysis provided a high level of discrimination among the isolates and could be used for the rapid screening of LAB starter cultures. PMID:25279017

Soro-Yao, Amenan A; Schumann, Peter; Thonart, Philippe; Djè, Koffi M; Pukall, Rüdiger

2014-01-01

230

Evaluation of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Rapid Identification of Beta-Hemolytic Streptococci?  

PubMed Central

This study was undertaken to evaluate matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the rapid identification of beta-hemolytic streptococci. We compared Bruker Biotyper 2.0 with Vitek2 coupled to the agglutination test. MALDI-TOF MS analysis of 386 beta-hemolytic streptococcal isolates yielded high-confidence identification to the species level for all 386 isolates. The Vitek2 gave high-confidence identification to the species level for 88% of Streptococcus agalactiae isolates (n = 269/306), 92% of Streptococcus pyogenes isolates (n = 48/52), and 39% of isolates of Streptococcus dysgalactiae serogroups C and G (n = 11/28). PMID:21697322

Cherkaoui, Abdessalam; Emonet, Stéphane; Fernandez, José; Schorderet, Didier; Schrenzel, Jacques

2011-01-01

231

Identification and quantification of flavonoids and chromes in Baeckea frutescens by using HPLC coupled with diode-array detection and quadruple time-of-flight mass spectrometry.  

PubMed

This article marks the first report on high-performance liquid chromatography (HPLC) coupled with diode-array detection (DAD) and quadruple time-of-flight mass spectrometry (Q-TOF/MS) for the identification and quantification of main bioactive constituents in Baeckea frutescens. In total, 24 compounds were identified or tentatively characterised based on their retention behaviours, UV profiles and MS fragment information. Furthermore, a validated method with good linearity, sensitivity, precision, stability, repeatability and accuracy was successfully applied for simultaneous determination of five flavonoids and one chromone in different plant parts of B. frutescens collected at different harvest times, and their dynamic contents revealed the appropriate harvest times. The established HPLC-DAD-Q-TOF/MS using multi-bioactive markers was proved to be a validated strategy for the quality evaluation on both raw materials and related products of B. frutescens. PMID:25466282

Jia, Bei-Xi; Huangfu, Qian-Qian; Ren, Feng-Xiao; Jia, Lu; Zhang, Yan-Bing; Liu, Hong-Min; Yang, Jie; Wang, Qiang

2014-12-01

232

A novel dereplication strategy for the identification of two new trace compounds in the extract of Gastrodia elata using UHPLC/Q-TOF-MS/MS.  

PubMed

An ultra performance liquid chromatography (UHPLC) coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS/MS) was used in the structural determination of natural compounds in Gastrodia elata. A total of 64 compounds were identified or tentatively characterized. The strategy used for characterization was comparing their retention time and fragmentation behaviors with those of the reference standards, or investigating their accurate mass measurements and characteristic fragmentation patterns followed by low-energy collision dissociation tandem mass spectrometry (CID-MS/MS). Phenolic conjugates mainly underwent consecutive losses of gastrodin residues and combined losses of H2O and CO2 from their citric acid units under negative MS/MS conditions. According to these rules, we have successfully characterized fifteen potential novel compounds. To confirm the reliability of this strategy, two targeted unknown trace parishins were obtained from G. elata by LC/MS-guided isolation. Based on the analysis of data from NMR spectroscopy and other techniques, the two unknown parishins were identified as 2-[4-O-(?-d-glucopyranosyl)benzyl]-3-methyl-citrate (parishin J) and 1,2-di-[4-O-(?-d-glucopyranosyl)benzyl]-3-methyl-citrate (parishin K), respectively. The fully established structures were consistent with the MS-oriented structural elucidation. This study expanded our knowledge on parishins in Gastrodia species, and the proposed strategy was proven efficient and reliable in the discovery of new minor compounds from herbal extracts. PMID:25746751

Li, Zhifeng; Wang, Yawei; Ouyang, Hui; Lu, Yu; Qiu, Yan; Feng, Yulin; Jiang, Hongliang; Zhou, Xin; Yang, Shilin

2015-04-15

233

Initializing a digital chromatography data archive for tropospheric air samples on Taunus Observatory Frankfurt by GC-TOF-MS  

NASA Astrophysics Data System (ADS)

The inception of a digital air archive for halogenated hydrocarbons will be presented. This archive is based on weekly samples taken at the Taunus Observatory on "Kleiner Feldberg" near Frankfurt/ Main, i.e. a very central position in Germany. The station is characterized by a mixture of clean air, moderately polluted air and occasional influence from the nearby city of Frankfurt. Regular meteorological and air quality data are available from the German Weather service (DWD) and the regional air quality monitoring (Hessiche Landesanstalt für Umwelt und Geologie, HLUG). Two air samples are collected in parallel in 2 l stainless steel flasks using a metal bellows pump. The air samples are analysed in the laboratory by gas chromatography coupled with Time of Flight Mass Spectrometry (GC TOF MS) and Quadrupole Mass Spectrometry (GC QUAD MS) for halogenated trace gases. Analysis is carried out no later than a month after sampling. Our current target species which will be measured by both mass spectrometers contain a wide range of halogenated trace gases, with calibration scales linked to both global monitoring networks, i.e. NOAA and AGAGE. A Time of Flight Mass Spectrometer has the advantage to measure a full mass range with a high sensitivity. Other measuring networks use Quadrupole mass spectrometers which need to be tuned to selected masses in order to achieve sufficient sensitivity. The full mass scan information available in the TOF data in combination with the high sensitivity of the instrument opens the possibility for retrospective analysis of the data in the future, as information on all substances which can be trapped and desorbed using our sampling technique are recorded, even though they may not be retrieved at the time of measurements. This will open the opportunity to have a look on historical developments even of yet undiscovered halogenated trace gases or those, which have not been subject to one's research focus until a certain time point but have become interesting later. The full resolution mass spectrometric data will be stored together with all meteorological and other information necessary for later reprocessing. This will constitute a digital air archive, which can also be made available to other research groups for reanalysis.

Hoker, Jesica; Obersteiner, Florian; Bönisch, Harald; Engel, Andreas

2014-05-01

234

Highly selective biomarkers for pesticides developed in Eisenia fetida using SELDI-TOF MS.  

PubMed

The repeated use of pesticides, and their subsequent residues, has contributed to severe adverse effects on the environment, including risks to human health. Therefore, it is important to assess the quality of the environment to ensure it remains free from pesticide residues. The six pesticides tested in this study showed high mortality on Eisenia fetida with LC50 values ranging from 7.7 to 37.9gL(-1). The strongest lethal effect resulted from the organochlorine insecticide endosulfan (LC50=7.7gL(-1)). Following exposure to the carbamate pesticides, acetylcholinesterase activity in E. fetida decreased dramatically in comparison to the control. Carboxylesterase activity was only lowered in E. fetida exposed to propoxur, when compared to the control. The remaining five pesticides had no significant effect on carboxylesterase activity in E. fetida. In order to discover pesticide-specific biomarkers with differentially expressed proteins after exposure to pesticides, protein patterns of pesticide-treated E. fetida were analyzed using SELDI-TOF MS with Q10 ProteinChips. Protein patterns were compared with their intensities at the same mass-to-charge ratios (m/z). All 42 peaks had intensities with associated p-values less than 0.089, and 40 of these peaks had associated p-values of 0.05. Using SELDI-TOF MS technology, selective biomarkers for the six pesticides tested were found in E. fetida; four proteins with 5425, 5697, 9523, and 9868 m/z were consistently observed in the earthworms following exposure to the carbamates. PMID:25682009

Park, Doo-San; Jeon, Hwang-Ju; Park, Eun-Sil; Bae, In Kyung; Kim, Yong-Eun; Lee, Sung-Eun

2015-03-01

235

"DUST BUSTER" - A Single Photon Ionization TOF MS for Cometary Dusts  

NASA Technical Reports Server (NTRS)

It is hard to predict the properties and composition of dust that will be returned by STARDUST from WED- 2. The most interesting but challenging case would be grains, pg to fg in weight, each carrying its own isotopic signature characteristic of its source zones in a variety of stars. How do we extract the maximum amount of science from such grains? Clearly, the best that can be accomplished is to measure every atom in each grain.Academia Sinica and Argonne National Laboratory (ANL) have entered into a collaboration to develop a SPI TOF MS instrument for analysis of stardust grains. A new instrument will be built at Academia Sinica based on the new TOF mass spectrometer design developed, built and operating at ANL. The instrument is intended for SPI TOF MS analysis of elements from Ca to Cu plus Li after first using SIMS to measure H, C, N, 0, Si, and S. There are still technical challenges facing the technique. We will need to improve submicrometer sample handling, avoid the effects of space charge, and increase the Mamie range of the detector. The most difficult obstacle to overcome may be the fact that the flux density of present high repetition rate, WV lasers is below the level needed to ensure full ionization (saturation) in the source region, which must be several mm in size to achieve the high useful yield needed for analysis of small stardust grains. A potential breakthrough effort is to exploit the novel free electron laser being pioneered at ANL. In principle, this FEL can reach ionization saturation and is tunable up to photon energies of 25 eV, which is higher than the ionization potential of any element.

Chen, C.-Y.; Calaway, W. F.; Lee, Typhoon; Moore, J. F.; Pellin, M. J.; Veryovkin, I. V.

2003-01-01

236

NMR, HPLC-ESI-MS, and MALDI-TOF MS analysis of condensed tannins from Delonix regia (Bojer ex Hook.) Raf. and their bioactivities.  

PubMed

The structures of the condensed tannins isolated from leaf, fruit, and stem bark of Delonix regia (Bojer ex Hook.) Raf. have been investigated with (13)C nuclear magnetic resonance ((13)C NMR) and high performance liquid chromatography electrospray ionization mass spectrometry (HPLC-ESI-MS) coupled with thiolysis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analyses. The results showed that these condensed tannins from D. regia possessed structural heterogeneity in monomer units and degree of polymerization. Propelargonidin (PP) and procyanidin (PC) were found in the leaf, fruit, and stem bark of D. regia, while prodelphinidin (PD) was found only in the leaves. The polymer chain lengths of condensed tannins from leaf and fruit organs were detected to be trimers to hexadecamers but from trimers to tridecamers for stem bark. B-type linkages were present in all these compounds. Condensed tannins from different parts of D. regia can be explored as tyrosinase inhibitors and food antioxidants because of their potent antityrosinase and antioxidant activities. The inhibitor concentration leading to 50% enzyme activity (IC(50)) was estimated to be 38 ± 1, 73 ± 2, and 54 ± 1.5 ?g/mL for the condensed tannins of leaf, fruit, and stem bark. Condensed tannins extracted from stem bark exhibited the highest antioxidant activity; the DPPH scavenging activity (IC(50)) and the FRAP values were 90 ± 2 ?g/mL and 5.42 ± 0.09 mmol AAE/g, respectively. PMID:22515734

Chai, Wei-Ming; Shi, Yan; Feng, Hui-Ling; Qiu, Ling; Zhou, Hai-Chao; Deng, Zi-Wei; Yan, Chong-Ling; Chen, Qing-Xi

2012-05-16

237

Misidentification of Saprochaete clavata as Magnusiomyces capitatus in Clinical Isolates: Utility of Internal Transcribed Spacer Sequencing and Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry and Importance of Reliable Databases  

PubMed Central

Saprochaete clavata and Magnusiomyces capitatus are human pathogens that are frequently mistaken for each other due to their similar phenotypes and erroneous or limited databases. Based on internal transcribed spacer (ITS) sequences, we propose species-specific carbon assimilation patterns and matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) fingerprints that enable the identification of S. clavata, M. capitatus, and Galactomyces candidus to the species level. PMID:24696028

Desnos-Ollivier, Marie; Blanc, Catherine; Garcia-Hermoso, Dea; Hoinard, Damien; Alanio, Alexandre

2014-01-01

238

Nontargeted metabolite profiling in compatible pathogen-inoculated tobacco (Nicotiana tabacum L. cv. Wisconsin 38) using UPLC-Q-TOF/MS.  

PubMed

A biphasic reactive oxygen species (ROS) production has previously been observed in tobacco at 1 and 48 h after inoculation with the hemibiotrophic compatible pathogen, Phytophthora parasitica var. nicotianae (Ppn). To characterize the response of tobacco to biphasically produced ROS concerning the propagation of Ppn, ultraperformance liquid chromatography-quadrupole-time of flight/ mass spectrometry (UPLC-Q-TOF/MS) based metabolic profiling combined with multivariate statistical analysis was performed. Among the nonredundant 355 mass ions in ESI+ mode and 345 mass ions in ESI- mode that were selected as significantly changed by Ppn inoculation (|p(corr)| > 0.6 on S-plot of orthogonal partial least-squares discriminant analysis (OPLS-DA), fold-change > 2, and p < 0.05 in the independent two-sample t test), 76 mass ions were identified on the basis of their accurate mass ions and MS/MS spectra. Phenolic amino acids, phenylpropanoids, hydroxycinnamic acid amides, linoleic acid, linolenic acid, lysophospholipids, glycoglycerolipids, and trioxidized phospholipids were identified as having changed after Ppn inoculation. On the basis of their quantitative changes, the metabolic responses occurring at each phase of ROS production after Ppn inoculation were investigated in this study. PMID:23072474

Cho, Kyoungwon; Kim, Yuran; Wi, Soo Jin; Seo, Jong Bok; Kwon, Joseph; Chung, Joo Hee; Park, Ky Young; Nam, Myung Hee

2012-11-01

239

Comparison and optimization of two MALDI-TOF MS platforms for the identification of medically relevant yeast species.  

PubMed

The rapid identification of yeast is essential for the optimization of antifungal therapy. The objective of our study was to evaluate two matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) platforms, the bioMérieux VITEK MS (IVD Knowledgebase v.2.0) and Bruker Biotyper (software version 3.1), for the rapid identification of medically relevant yeast. One hundred and seventeen isolates, representing six genera and 18 species, were analyzed using multiple direct smear methods to optimize identification. Sequence analysis was the gold standard for comparison. Isolates were analyzed with VITEK MS using the direct smear method +/- a 25 % formic acid on-plate extraction. For Biotyper, isolates were analyzed using direct smear without formic acid, and with 25 % and 100 % formic acid on-plate extractions. When all methods were included, VITEK MS correctly identified 113 (96.6 %) isolates after 24 h with one misidentification, and Biotyper correctly identified 77 (65.8 %) isolates using a threshold of ?2.0 with no misidentifications. Using a revised threshold of ?1.7, Biotyper correctly identified 103 (88.0 %) isolates, with 3 (2.6 %) misidentifications. For both platforms, the number of identifications was significantly increased using a formic acid overlay (VITEK MS, p?

Pence, M A; McElvania TeKippe, E; Wallace, M A; Burnham, C-A D

2014-10-01

240

Comprehensive quantitative analysis of Shuang-Huang-Lian oral liquid using UHPLC-Q-TOF-MS and HPLC-ELSD.  

PubMed

Shuang-Huang-Lian oral liquid (SHL) is a well-known Chinese patent drug containing three herbal medicines: Radix Scutellariae, Flos Lonicerae Japonicae and Fructus Forsythiae. It is usually used to treat acute upper respiratory tract infection caused by virus or bacteria. Although the licensing of botanical drug Veregen approved by FDA has indicated the importance of quantitative analysis in quality control of herbal medicines, quantitative evaluation of a Chinese patent drug like SHL remains a challenge due to the complex chemical profile. In this study, 15 small molecular components of SHL (four flavonoids, six quinic acid derivatives, three saponins and two phenylethanoid glycosides) were simultaneously determined using ultra-high performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). The contents of the three major saccharides, namely fructose, glucose and sucrose were quantified using high performance liquid chromatography-evaporative light scattering detector on an amino column (HPLC-ELSD). The macromolecules were quantified by precipitating in 80% ethanol, drying the precipitate, and then weighing. The established methods were validated in terms of linearity, sensitivity, precision, accuracy and stability and then successfully applied to analyze 12 batches of commercial products of SHL produced by four different manufacturers. The results indicated that 57.52-78.11% (w/w) of SHL could be quantitatively determined (non-saccharide small molecules: 1.77-3.75%, monosaccharides: 0.93-20.93%, macromolecules: 2.63-5.76% and sucrose: 49.20-65.94%). This study may provide a useful way to comprehensively evaluate the quality of SHL. PMID:25222137

Zhang, Tian-Bo; Yue, Rui-Qi; Xu, Jun; Ho, Hing-Man; Ma, Dik-Lung; Leung, Chung-Hang; Chau, Siu-Leung; Zhao, Zhong-Zhen; Chen, Hu-Biao; Han, Quan-Bin

2015-01-01

241

Prospective Evaluation of a Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System in a Hospital Clinical Microbiology Laboratory for Identification of Bacteria and Yeasts: a Bench-by-Bench Study for Assessing the Impact on Time to Identification and Cost-Effectiveness  

PubMed Central

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has been found to be an accurate, rapid, and inexpensive method for the identification of bacteria and yeasts. Previous evaluations have compared the accuracy, time to identification, and costs of the MALDI-TOF MS method against standard identification systems or commercial panels. In this prospective study, we compared a protocol incorporating MALDI-TOF MS (MALDI protocol) with the current standard identification protocols (standard protocol) to determine the performance in actual practice using a specimen-based, bench-by-bench approach. The potential impact on time to identification (TTI) and costs had MALDI-TOF MS been the first-line identification method was quantitated. The MALDI protocol includes supplementary tests, notably for Streptococcus pneumoniae and Shigella, and indications for repeat MALDI-TOF MS attempts, often not measured in previous studies. A total of 952 isolates (824 bacterial isolates and 128 yeast isolates) recovered from 2,214 specimens were assessed using the MALDI protocol. Compared with standard protocols, the MALDI protocol provided identifications 1.45 days earlier on average (P < 0.001). In our laboratory, we anticipate that the incorporation of the MALDI protocol can reduce reagent and labor costs of identification by $102,424 or 56.9% within 12 months. The model included the fixed annual costs of the MALDI-TOF MS, such as the cost of protein standards and instrument maintenance, and the annual prevalence of organisms encountered in our laboratory. This comprehensive cost analysis model can be generalized to other moderate- to high-volume laboratories. PMID:22855510

Tan, K. E.; Ellis, B. C.; Lee, R.; Stamper, P. D.; Zhang, S. X.

2012-01-01

242

MALDI-TOF MS analysis of ribosomal proteins coded in S10 and spc operons rapidly classified the Sphingomonadaceae as alkylphenol polyethoxylate-degrading bacteria from the environment.  

PubMed

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) using ribosomal subunit proteins coded in the S10-spc-alpha operon as biomarkers was applied for the classification of the Sphingomonadaceae from the environment. To construct a ribosomal protein database, S10-spc-alpha operon of type strains of the Sphingomonadaceae and their related alkylphenol polyethoxylate (APEO(n) )-degrading bacteria were sequenced using specific primers designed based on nucleotide sequences of genome-sequenced strains. The observed MALDI mass spectra of intact cells were compared with the theoretical mass of the constructed ribosomal protein database. The nine selected biomarkers coded in the S10-spc-alpha operon, L18, L22, L24, L29, L30, S08, S14, S17, and S19, could successfully distinguish the Sphingopyxis terrae NBRC 15098(T) and APEO(n) -degrading bacteria strain BSN20, despite only one base difference in the 16S rRNA gene sequence. This method, named the S10-GERMS (S10-spc-alpha operon gene-encoded ribosomal protein mass spectrum) method, is a significantly useful tool for bacterial discrimination of the Sphingomonadaceae at the strain level and can detect and monitor the main APEO(n) -degrading bacteria in the environment. PMID:22324315

Hotta, Yudai; Sato, Hiroaki; Hosoda, Akifumi; Tamura, Hiroto

2012-05-01

243

Comprehensive chemical profiling of guizhi fuling capsule by the combined use of gas chromatography-mass spectrometry with a deconvolution software and rapid-resolution liquid chromatography quadrupole time-of-flight tandem mass spectrometry.  

PubMed

Herbal formulations are complex natural mixtures. Researchers usually tend to focus more on analysis of nonvolatile components but pay less attention to volatile compounds. In this study, an analytical strategy combining two approaches was established for comprehensive analysis of herbal formulations. Guizhi Fuling capsule (GFC), a drug approved by the FDA to enter phase II clinical trial for treatment of primary dysmenorrhea, was taken as a case for analysis. Gas chromatography-mass spectrometry (GC-MS) with automated mass spectral deconvolution and identification system (AMDIS) led to rapid identification of 48 volatile components including four acetophenones, three fatty acid esters, 13 phenylpropanoids and 19 sesquiterpenes. Most of them were found from Guizhi. The volatile oils of Guizhi have been proved to exhibit many pharmacological activities. This is helpful in understanding the pharmacological mechanism of GFC. Furthermore, AMDIS turned out to be efficient and reliable for analysis of complex herbal formulations. Rapid-resolution liquid chromatography (RRLC) coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI-Q-TOF MS/MS) allowed the identification of 70 nonvolatile components including six acetophenones, 12 galloyl glucoses, 31 monoterpene glycosides, three phenols and 12 triterpene acids. Fragmentation behaviors of assigned components, especially triterpene acids, which are hard to identify by low-resolution MS, were first investigated by TOF MS/MS. Characteristic ions and typical loss of assigned triterpene acids were summarized. Combinatorial use of GC-MS-AMDIS and RRLC-ESI-Q-TOF MS/MS could be of great help in global qualitative analysis of GFC, as well as other herbal products. PMID:22297903

Wang, Ya-Qiong; Qi, Lian-Wen; Aa, Jiye; Wang, Guang-Ji; Gao, Wen; Cheng, Shu-Jie; Wang, Zhen-Zhong; Xiao, Wei; Li, Ping

2012-10-01

244

Chemical analysis of pharmaceuticals and explosives in fingermarks using matrix-assisted laser desorption ionization/time-of-flight mass spectrometry.  

PubMed

Chemical analysis of latent fingermarks, "touch chemistry," has the potential of providing intelligence or forensically relevant information. Matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI/TOF MS) was used as an analytical platform for obtaining mass spectra and chemical images of target drugs and explosives in fingermark residues following conventional fingerprint development methods and MALDI matrix processing. There were two main purposes of this research: (1) develop effective laboratory methods for detecting drugs and explosives in fingermark residues and (2) determine the feasibility of detecting drugs and explosives after casual contact with pills, powders, and residues. Further, synthetic latent print reference pads were evaluated as mimics of natural fingermark residue to determine if the pads could be used for method development and quality control. The results suggest that artificial amino acid and sebaceous oil residue pads are not suitable to adequately simulate natural fingermark chemistry for MALDI/TOF MS analysis. However, the pads were useful for designing experiments and setting instrumental parameters. Based on the natural fingermark residue experiments, handling whole or broken pills did not transfer sufficient quantities of drugs to allow for definitive detection. Transferring drugs or explosives in the form of powders and residues was successful for preparing analytes for detection after contact with fingers and deposition of fingermark residue. One downfall to handling powders was that the analyte particles were easily spread beyond the original fingermark during development. Analyte particles were confined in the original fingermark when using transfer residues. The MALDI/TOF MS was able to detect procaine, pseudoephedrine, TNT, and RDX from contact residue under laboratory conditions with the integration of conventional fingerprint development methods and MALDI matrix. MALDI/TOF MS is a nondestructive technique which provides chemical information in both the mass spectra and chemical images. PMID:24447453

Kaplan-Sandquist, Kimberly; LeBeau, Marc A; Miller, Mark L

2014-02-01

245

Experimental validation of an effective carbon number-based approach for the gas chromatography-mass spectrometry quantification of 'compounds lacking authentic standards or surrogates'.  

PubMed

For the quantitative analysis of 'compounds lacking authentic standards or surrogates' (CLASS) in environmental media, we previously introduced an effective carbon number (ECN) approach to develop an empirical equation for the prediction of their response factor (RF). In this research, a series of laboratory experiments were carried out to benchmark the reliability of an ECN approach for sorbent tube/thermal desorption/gas chromatography (GC)/mass spectrometry (MS) applications. First, the ECN values were determined using external calibration data from 25 reference volatile organic compounds (VOCs) using two MS dectectors (quadrupole (Q) and time-of-flight (TOF)). Then, a certified standard mixture of 54 VOCs was analyzed by each system as a simulated unknown sample. The analytical bias, assessed in terms of percentage difference (PD) between the certified and ECN-predicted mass values, averaged 19.2±16.1% (TOF-MS) and 28.2±27.6% (Q-MS). The bias using a more simplified carbon number (CN)-based prediction increased considerably, yielding 53.4±53.3% (TOF-MS) and 61.7±81.3% (Q-MS). However, the bias obtained using the ECN-based prediction decreased significantly to yield average PD values of 9.84±7.28% (TOF-MS) and 16.8±8.35% (Q-MS), if the comparison was limited to 26 (out of 54) VOCs with CN?4 (i.e., 25 aromatics and hexachlorobutadiene). PMID:24856509

Kim, Yong-Hyun; Kim, Ki-Hyun; Szulejko, Jan E; Bae, Min-Suk; Brown, Richard J C

2014-06-01

246

Ribosomal proteins as biomarkers for bacterial identification by mass spectrometry in the clinical microbiology laboratory  

PubMed Central

Whole-cell matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) is a rapid method for identification of microorganisms that is increasingly used in microbiology laboratories. This identification is based on the comparison of the tested isolate mass spectrum with reference databases. Using Neisseria meningitidis as a model organism, we showed that in one of the available databases, the Andromas database, 10 of the 13 species-specific biomarkers correspond to ribosomal proteins. Remarkably, one biomarker, ribosomal protein L32, was subject to inter-strain variability. The analysis of the ribosomal protein patterns of 100 isolates for which whole genome sequences were available, confirmed the presence of inter-strain variability in the molecular weight of 29 ribosomal proteins, thus establishing a correlation between the sequence type (ST) and/or clonal complex (CC) of each strain and its ribosomal protein pattern. Since the molecular weight of three of the variable ribosomal proteins (L30, L31 and L32) was included in the spectral window observed by MALDI-TOF MS in clinical microbiology, i.e., 3640–12000 m/z, we were able by analyzing the molecular weight of these three ribosomal proteins to classify each strain in one of six subgroups, each of these subgroups corresponding to specific STs and/or CCs. Their detection by MALDI-TOF allows therefore a quick typing of N. meningitidis isolates. PMID:23916798

Suarez, Stéphanie; Ferroni, Agnès; Lotz, Aurélie; Jolley, Keith A.; Guérin, Philippe; Leto, Julie; Dauphin, Brunhilde; Jamet, Anne; Maiden, Martin C.J.; Nassif, Xavier; Armengaud, Jean

2014-01-01

247

Ribosomal proteins as biomarkers for bacterial identification by mass spectrometry in the clinical microbiology laboratory.  

PubMed

Whole-cell matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a rapid method for identification of microorganisms that is increasingly used in microbiology laboratories. This identification is based on the comparison of the tested isolate mass spectrum with reference databases. Using Neisseria meningitidis as a model organism, we showed that in one of the available databases, the Andromas database, 10 of the 13 species-specific biomarkers correspond to ribosomal proteins. Remarkably, one biomarker, ribosomal protein L32, was subject to inter-strain variability. The analysis of the ribosomal protein patterns of 100 isolates for which whole genome sequences were available, confirmed the presence of inter-strain variability in the molecular weight of 29 ribosomal proteins, thus establishing a correlation between the sequence type (ST) and/or clonal complex (CC) of each strain and its ribosomal protein pattern. Since the molecular weight of three of the variable ribosomal proteins (L30, L31 and L32) was included in the spectral window observed by MALDI-TOF MS in clinical microbiology, i.e., 3640-12000 m/z, we were able by analyzing the molecular weight of these three ribosomal proteins to classify each strain in one of six subgroups, each of these subgroups corresponding to specific STs and/or CCs. Their detection by MALDI-TOF allows therefore a quick typing of N. meningitidis isolates. PMID:23916798

Suarez, Stéphanie; Ferroni, Agnès; Lotz, Aurélie; Jolley, Keith A; Guérin, Philippe; Leto, Julie; Dauphin, Brunhilde; Jamet, Anne; Maiden, Martin C J; Nassif, Xavier; Armengaud, Jean

2013-09-01

248

Mass Spectrometry for Proteomics  

PubMed Central

Summary Mass spectrometry has been widely used to analyze biological samples and has evolved into an indispensable tool for proteomics research. Our desire to understand the proteome has led to new technologies that push the boundary of mass spectrometry capabilities, which in return has allowed mass spectrometry to address an ever-increasing array of biological questions. The recent development of a novel mass spectrometer (Orbitrap) and new dissociation methods such as electron transfer dissociation have made possible exciting new areas of proteomic application. Although bottom-up proteomics (analysis of proteolytic peptide mixtures) remains the workhorse for proteomic analysis, middle- and top-down strategies (analysis of longer peptides and intact proteins, respectively) should allow more complete characterization of protein isoforms and post-translational modifications. Finally, stable isotope labeling strategies have transformed mass spectrometry from merely descriptive to a tool for measuring dynamic changes in protein expression, interaction and modification. PMID:18718552

Han, Xuemei; Aslanian, Aaron; Yates, John R.

2008-01-01

249

Proteomic study of serum using gel chromatography and MALDI-TOF MS reveals diagnostic biomarkers in male patients with liver-cancer  

NASA Astrophysics Data System (ADS)

Human serum has been widely employed clinically for diagnosing various fatal diseases. However, the concentration of most proteins in human serum is too low to be directly measured using normal analytical methods. In order to obtain reliable analytical results from proteomic analysis of human serum, appropriate sample preparation is essential. A combined off-line analytical technique of gel chromatography and matrix-assisted laser desorption ionization/time of flight mass spectrometry (MALDI-TOF MS) has been successfully established to separate proteins for MS analysis. Using these combined techniques, 176 mass signal peaks of proteins/peptides were found in 6 of 18 fractions from normal male serum (NMS) in the presence of buffer consisting of NH4HCO3 and acetonitrile. A simple gel chromatography column packed with Sephadex G-50 removed most signal-suppressing compounds such as salts and high abundance proteins (HAP). The molecular mass to charge (m/z) ratios of differential peptides revealed in serum of male patient with liver-cancer (LCMPS) compared to NMS were 5365, 5644 and 6462, and these peptides can be used as biomarkers to clinically diagnose liver-cancer. The simple and convenient chromatographic method described here is not only superior to recently described HPLC separation for MS analysis, but also reveals many novel and significant serum biomarkers for the clinical diagnosis of various diseases.

Zeng, Xin-Hua; Huang, He-Qing; Chen, Dong-Shi; Jin, Hong-Wei; Huang, Hui-Ying

2007-03-01

250

Fourier transform mass spectrometry.  

PubMed

This article provides an introduction to Fourier transform-based mass spectrometry. The key performance characteristics of Fourier transform-based mass spectrometry, mass accuracy and resolution, are presented in the view of how they impact the interpretation of measurements in proteomic applications. The theory and principles of operation of two types of mass analyzer, Fourier transform ion cyclotron resonance and Orbitrap, are described. Major benefits as well as limitations of Fourier transform-based mass spectrometry technology are discussed in the context of practical sample analysis, and illustrated with examples included as figures in this text and in the accompanying slide set. Comparisons highlighting the performance differences between the two mass analyzers are made where deemed useful in assisting the user with choosing the most appropriate technology for an application. Recent developments of these high-performing mass spectrometers are mentioned to provide a future outlook. PMID:21742802

Scigelova, Michaela; Hornshaw, Martin; Giannakopulos, Anastassios; Makarov, Alexander

2011-07-01

251

OmpU as a biomarker for rapid discrimination between toxigenic and epidemic Vibrio cholerae O1/O139 and non-epidemic Vibrio cholerae in a modified MALDI-TOF MS assay  

PubMed Central

Background Cholera is an acute diarrheal disease caused by Vibrio cholerae. Outbreaks are caused by a genetically homogenous group of strains from serogroup O1 or O139 that are able to produce the cholera toxin. Rapid detection and identification of these epidemic strains is essential for an effective response to cholera outbreaks. Results The use of ferulic acid as a matrix in a new MALDI-TOF MS assay increased the measurable mass range of existing MALDI-TOF MS protocols for bacterial identification. The assay enabled rapid discrimination between epidemic V. cholerae O1/O139 strains and other less pathogenic V. cholerae strains. OmpU, an outer membrane protein whose amino acid sequence is highly conserved among epidemic strains of V. cholerae, appeared as a discriminatory marker in the novel MALDI-TOF MS assay. Conclusions The extended mass range of MALDI-TOF MS measurements obtained by using ferulic acid improved the screening for biomarkers in complex protein mixtures. Differences in the mass of abundant homologous proteins due to variation in amino acid sequences can rapidly be examined in multiple samples. Here, a rapid MALDI-TOF MS assay was developed that could discriminate between epidemic O1/O139 strains and other less pathogenic V. cholerae strains based on differences in mass of the OmpU protein. It appeared that the amino acid sequence of OmpU from epidemic V. cholerae O1/O139 strains is unique and highly conserved. PMID:24943244

2014-01-01

252

Orbitrap mass spectrometry.  

PubMed

Orbitrap is the newest addition to the family of high-resolution mass spectrometry analyzers. With its revolutionarily new, miniature design, Orbitrap combines high speed with excellent quantification properties, ranking favorably in many analytical applications. PMID:23590404

Zubarev, Roman A; Makarov, Alexander

2013-06-01

253

Sequence analysis of styrenic copolymers by tandem mass spectrometry.  

PubMed

Styrene and smaller molar amounts of either m-dimethylsilylstyrene (m-DMSS) or p-dimethylsilylstyrene (p-DMSS) were copolymerized under living anionic polymerization conditions, and the compositions, architectures, and sequences of the resulting copolymers were characterized by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and tandem mass spectrometry (MS(2)). MS analysis revealed that linear copolymer chains containing phenyl-Si(CH3)2H pendants were the major product for both DMSS comonomers. In addition, two-armed architectures with phenyl-Si(CH3)2-benzyl branches were detected as minor products. The comonomer sequence in the linear chains was established by MS(2) experiments on lithiated oligomers, based on the DMSS content of fragments generated by backbone C-C bond scissions and with the help of reference MS(2) spectra obtained from a polystyrene homopolymer and polystyrene end-capped with a p-DMSS block. The MS(2) data provided conclusive evidence that copolymerization of styrene/DMSS mixtures leads to chains with a rather random distribution of the silylated comonomer when m-DMSS is used, but to chains with tapered block structures, with the silylated units near the initiator, when p-DMSS is used. Hence, MS(2) fragmentation patterns permit not only differentiation of the sequences generated in the synthesis, but also the determination of specific comonomer locations along the polymer chain. PMID:25181590

Yol, Aleer M; Janoski, Jonathan; Quirk, Roderic P; Wesdemiotis, Chrys

2014-10-01

254

Fourier Transform Mass Spectrometry.  

ERIC Educational Resources Information Center

Discusses the nature of Fourier transform mass spectrometry and its unique combination of high mass resolution, high upper mass limit, and multichannel advantage. Examines its operation, capabilities and limitations, applications (ion storage, ion manipulation, ion chemistry), and future applications and developments. (JN)

Gross, Michael L.; Rempel, Don L.

1984-01-01

255

Evaluation of MALDI-TOF mass spectrometry and Sepsityper Kit™ for the direct identification of organisms from sterile body fluids in a Canadian pediatric hospital  

PubMed Central

Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) can be used to identify bacteria directly from positive blood and sterile fluid cultures. The authors evaluated a commercially available kit – the Sepsityper Kit (Bruker Daltonik, Germany) – and MALDI-TOF MS for the rapid identification of organisms from 80 flagged positive blood culture broths, of which 73 (91.2%) were blood culture specimens and seven (8.7%) were cerebrospinal fluid specimens, in comparison with conventional identification methods. Correct identification to the genus and species levels was obtained in 75 of 80 (93.8%) and 39 of 50 (78%) blood culture broths, respectively. Applying the blood culture analysis module, a newly developed software tool, improved the species identification of Gram-negative organisms from 94.7% to 100% and of Gram-positive organisms from 66.7% to 70%. MALDI-TOF MS is a promising tool for the direct identification of organisms cultured from sterile sites. PMID:24489560

Tadros, Manal; Petrich, Astrid

2013-01-01

256

Identification of Mycobacteria in Solid-Culture Media by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry?  

PubMed Central

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has recently been introduced into the clinical microbiology laboratory as a rapid and accurate method to identify bacteria and yeasts. In this paper we describe our work on the use of MALDI-TOF MS for the identification of mycobacterial isolates. We developed a protocol for protein extraction from mycobacteria and utilized it to construct a database containing 42 clinically relevant type and reference strains of mycobacteria. The database was used to identify 104 clinical isolates of mycobacteria. All members of the Mycobacterium tuberculosis complex were identified accurately at the complex level but could not be separated at the species level. All other organisms were identified at the species level, with the exception of one strain of M. kansasii (accurately identified but with a low spectral score) and three pairs of closely related strains: M. abscessus and M. massiliense, M. mucogenicum and M. phocaicum, and M. chimaera and M. intracellulare. These pairs of organisms can currently be identified only by multilocus gene sequence analysis. We conclude that MALDI-TOF MS analysis can be incorporated into the work flow of the microbiology laboratory for rapid and accurate identification of most strains of mycobacteria isolated from solid growth media. PMID:21411597

Saleeb, Paul G.; Drake, Steven K.; Murray, Patrick R.; Zelazny, Adrian M.

2011-01-01

257

Efficient monitoring of enzymatic conjugation reaction by surface-enhanced laser desorption/ionization time of flight mass spectrometry for process optimization.  

PubMed

Efficient analysis of bioconjugation reactions is one the most challenging task for optimizing and eventually achieving the reproducible production of large amount of conjugates. In particular, the complexity of some reaction mixtures precludes the use of most of the existing methods, because of the presence of large amounts of contaminants. As an alternative method, we used surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) for monitoring an in vitro enzymatic transglycosylation of N-acetylgalactosamine (GalNAc) residues to a recombinant mucin protein MUC6. For this reaction, catalyzed by the uridine 5'-diphospho-N-acetylgalactosamine:polypeptide N-acetylgalactosaminyltransferases (ppGalNAc-Ts), we used either a recombinant ppGalNAc-T1 or a mixture of ppGalNAc-Ts contained in MCF7 tumor cell extracts. In the present study, we show that SELDI-TOF MS offers unique advantages over the traditional methodologies. It is a rapid, accurate, sensitive, reproducible, and very convenient analytical method for monitoring the course of a bioconjugation, even in heterogeneous samples such as cell extracts. SELDI-TOF MS proved very useful for optimizing the reaction parameters of the transglycosylation and for achieving the large scale preparation of Tn antigen-glycosylated mucins for antitumor immunotherapy applications. PMID:16536491

Freire, Teresa; D'Alayer, Jacques; Bay, Sylvie

2006-01-01

258

MetPP: a computational platform for comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry-based metabolomics  

PubMed Central

Motivation: Due to the high complexity of metabolome, the comprehensive 2D gas chromatography time-of-flight mass spectrometry (GC×GC-TOF MS) is considered as a powerful analytical platform for metabolomics study. However, the applications of GC×GC-TOF MS in metabolomics are not popular owing to the lack of bioinformatics system for data analysis. Results: We developed a computational platform entitled metabolomics profiling pipeline (MetPP) for analysis of metabolomics data acquired on a GC×GC-TOF MS system. MetPP can process peak filtering and merging, retention index matching, peak list alignment, normalization, statistical significance tests and pattern recognition, using the peak lists deconvoluted from the instrument data as its input. The performance of MetPP software was tested with two sets of experimental data acquired in a spike-in experiment and a biomarker discovery experiment, respectively. MetPP not only correctly aligned the spiked-in metabolite standards from the experimental data, but also correctly recognized their concentration difference between sample groups. For analysis of the biomarker discovery data, 15 metabolites were recognized with significant concentration difference between the sample groups and these results agree with the literature results of histological analysis, demonstrating the effectiveness of applying MetPP software for disease biomarker discovery. Availability: The source code of MetPP is available at http://metaopen.sourceforge.net Contact: xiang.zhang@louisville.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:23665844

Wei, Xiaoli; Shi, Xue; Koo, Imhoi; Kim, Seongho; Schmidt, Robin H.; Arteel, Gavin E.; Watson, Walter H.; McClain, Craig; Zhang, Xiang

2013-01-01

259

Comparison of the Bruker MALDI-TOF Mass Spectrometry System and Conventional Phenotypic Methods for Identification of Gram-Positive Rods  

PubMed Central

In recent years, MALDI-TOF Mass Spectrometry (MS) method has emerged as a promising and a reliable tool for bacteria identification. In this study we compared Bruker MALDI-TOF MS and conventional phenotypic methods to identify a collection of 333 Gram-positive clinical isolates comprising 22 genera and 60 species. 16S rRNA sequencing was the reference molecular technique, and rpoB gene sequecing was used as a secondary gene target when 16Sr RNA did not allow species identification of Corynebacterium spp. We also investigate if score cut-offs values of ?1,5 and ?1,7 were accurate for genus and species-level identification using the Bruker system. Identification at species level was obtained for 92,49% of Gram-positive rods by MALDI-TOF MS compared to 85,89% by phenotypic method. Our data validates the score ?1,5 for genus level and ?1,7 for species-level identification in a large and diverse collection of Gram-positive rods. The present study has proved the accuracy of MALDI-TOF MS as an identification method in Gram-positive rods compared to currently used methods in routine laboratories. PMID:25184254

Barberis, Claudia; Almuzara, Marisa; Join-Lambert, Olivier; Ramírez, María Soledad; Famiglietti, Angela; Vay, Carlos

2014-01-01

260

Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry To Resolve Complex Clinical Cases of Patients with Recurrent Bacteremias  

PubMed Central

Matrix-assisted laser desorption–ionization time of flight mass spectrometry (MALDI-TOF MS) is a rapid and accurate method of identifying microorganisms. Throughout Europe, it is already in routine use but has not yet been widely implemented in the United States, pending FDA approval. Here, we describe two medically complex patients at a large tertiary-care academic medical center with recurring bacteremias caused by distinct but related species. Bacterial identifications were initially obtained using the Vitek-2 system with the GPI card for Enterococcus and the API system for staphylococci. Initial results misled clinicians as to the source and proper management of these patients. Retrospective investigation with MALDI-TOF MS clarified the diagnosis by identifying a single microorganism as the pathogen in each case. To our knowledge, this is one of the first reports in the United States demonstrating the use of MALDI-TOF MS to facilitate the clinical diagnosis in patients with recurrent bacteremias of unclear source. PMID:23536408

Nori, Priya; Ostrowsky, Belinda; Dorokhova, Olena; Gialanella, Philip; Moy, Morgan; Muggia, Victoria; Grossberg, Robert; Kornblum, John; Lin, Ying

2013-01-01

261

Differentiation of Lactobacillus brevis strains using Matrix-Assisted-Laser-Desorption-Ionization-Time-of-Flight Mass Spectrometry with respect to their beer spoilage potential.  

PubMed

Lactobacillus (L.) brevis is one of the most frequently encountered bacteria in beer-spoilage incidents. As the species Lactobacillus brevis comprises strains showing varying ability to grow in beer, ranging from growth in low hopped wheat to highly hopped pilsner beer, differentiation and classification of L. brevis with regard to their beer-spoiling ability is of vital interest for the brewing industry. Matrix-Assisted-Laser-Desorption-Ionization-Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) has been shown as a powerful tool for species and sub-species differentiation of bacterial isolates and is increasingly used for strain-level differentiation. Seventeen L. brevis strains, representative of different spoilage types, were characterized according to their tolerance to iso-alpha-acids and their growth in wheat-, lager- and pilsner beer. MALDI-TOF MS spectra were acquired to perform strain-level identification, cluster analysis and biomarker detection. Strain-level identification was achieved in 90% out of 204 spectra. Misidentification occurred nearly exclusively among strains belonging to the same spoilage type. Though spectra of strongly beer-spoiling strains showed remarkable similarity, no decisive single markers were detected to be present in all strains of one group. However, MALDI-TOF MS spectra can be reliably assigned to the corresponding strain and thus allow to track single strains and connect them to their physiological properties. PMID:24549193

Kern, Carola C; Vogel, Rudi F; Behr, Jürgen

2014-06-01

262

Classification Algorithm for Subspecies Identification within the Mycobacterium abscessus Species, Based on Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry  

PubMed Central

Mycobacterium abscessus, as a species, has been increasingly implicated in respiratory infections, notably in cystic fibrosis patients. The species comprises 3 subspecies, which can be difficult to identify. Since they differ in antibiotic susceptibility and clinical relevance, developing a routine diagnostic tool discriminating Mycobacterium abscessus at the subspecies level is a real challenge. Forty-three Mycobacterium abscessus species isolates, previously identified by multilocus sequence typing, were analyzed by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). A subspecies identification algorithm, based on five discriminating peaks, was drawn up and validated by blind identification of a further 49 strains, 94% of which (n = 46) were correctly identified. Two M. abscessus subsp. massiliense strains were misidentified as M. abscessus subsp. abscessus, and for 1 other strain identification failed. Inter- and intralaboratory reproducibility tests were conclusive. This study presents, for the first time, a classification algorithm for MALDI-TOF MS identification of the 3 M. abscessus subspecies. MALDI-TOF MS proved effective in discriminating within the M. abscessus species and might be easily integrated into the workflow of microbiology labs. PMID:25009048

Fangous, Marie-Sarah; Mougari, Faiza; Gouriou, Stéphanie; Calvez, Elodie; Raskine, Laurent; Cambau, Emmanuelle; Payan, Christopher

2014-01-01

263

Use of proton transfer reaction time-of-flight mass spectrometry for the analytical detection of illicit and controlled prescription drugs at room temperature via direct headspace sampling.  

PubMed

The first reported use of proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) for the detection of a range of illicit and prescribed drugs is presented here. We describe the capabilities of PTR-TOF-MS to detect the following commonly used narcotics-ecstasy (N-methyl-3,4-methylenedioxyamphetamine), morphine, codeine, cocaine and heroin-by the direct sampling of the headspace above small solid quantities (approximately 50 mg) of the drugs placed in glass vials at room temperature, i.e. with no heating of the sample and no pre-concentration. We demonstrate in this paper the ability to identify the drugs, both illicit and prescribed, using PTR-TOF-MS through the accurate m/z assignment of the protonated parent molecule to the second decimal place. We have also included in this study measurements with an impure sample of heroin, containing typical substances found in "street" heroin, to illustrate the use of the technology for more "real-world" samples. Therefore, in a real-world complex chemical environment, a high level of confidence can be placed on the detection of drugs. Although the protonated parent is observed for all drugs, the reactant channel leading to this species is not the only one observed and neither is it necessarily the most dominant. Details on the observed fragmentation behaviour are discussed and compared to electrospray ionisation MS(n) studies available in the literature. PMID:21475946

Agarwal, B; Petersson, F; Jürschik, S; Sulzer, P; Jordan, A; Märk, T D; Watts, P; Mayhew, C A

2011-06-01

264

Successful Identification of Clinical Dermatophyte and Neoscytalidium Species by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry  

PubMed Central

Dermatophytes are keratinolytic fungi responsible for a wide variety of diseases of glabrous skin, nails, and hair. Their identification, currently based on morphological criteria, is hindered by intraspecies morphological variability and the atypical morphology of some clinical isolates. The aim of this study was to evaluate matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) as a routine tool for identifying dermatophyte and Neoscytalidium species, both of which cause dermatomycoses. We first developed a spectral database of 12 different species of common and unusual dermatophytes and two molds responsible for dermatomycoses (Neoscytalidium dimidiatum and N. dimidiatum var. hyalinum). We then prospectively tested the performance of the database on 381 clinical dermatophyte and Neoscytalidium isolates. Correct identification of the species was obtained for 331/360 dermatophytes (91.9%) and 18/21 Neoscytalidium isolates (85.7%). The results of MALDI-TOF MS and standard identification disagreed for only 2 isolates. These results suggest that MALDI-TOF MS could be a useful tool for routine and fast identification of dermatophytes and Neoscytalidium spp. in clinical mycology laboratories. PMID:22535981

Alshawa, Kinda; Beretti, Jean-Luc; Lacroix, Claire; Feuilhade, Martine; Dauphin, Brunhilde; Quesne, Gilles; Hassouni, Noura; Nassif, Xavier

2012-01-01

265

What is new in clinical microbiology-microbial identification by MALDI-TOF mass spectrometry: a paper from the 2011 William Beaumont Hospital Symposium on molecular pathology.  

PubMed

Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) offers the possibility of accurate, rapid, inexpensive identification of bacteria, fungi, and mycobacteria isolated in clinical microbiology laboratories. The procedures for preanalytic processing of organisms and analysis by MALDI-TOF MS are technically simple and reproducible, and commercial databases and interpretive algorithms are available for the identification of a wide spectrum of clinically significant organisms. Although only limited work has been reported on the use of this technique to identify molds, perform strain typing, or determine antibiotic susceptibility results, these are fruitful areas of promising research. As experience is gained with MALDI-TOF MS, it is expected that the databases will be expanded to resolve many of the current inadequate identifications (eg, no identification, genus-level identification) and algorithms for potential misidentification will be developed. The current lack of Food and Drug Administration approval of any MALDI-TOF MS system for organism identification limits widespread use in the United States. PMID:22795961

Murray, Patrick R

2012-09-01

266

Recognition of Clostridium difficile PCR-ribotypes 001, 027 and 126/078 using an extended MALDI-TOF MS system.  

PubMed

During the last decade, Clostridium difficile infection (CDI) increased markedly inside as well as outside of hospitals. In association with the occurrence of new hypervirulent C. difficile strains, CDI became more important. Until now typing of C. difficile strains has been enabled by PCR-ribotyping. However, this method is restricted to specialized laboratories combined with high maintenance cost. Therefore, we tested MALDI-TOF mass spectrometry for typing of C. difficile to provide a fast method for surveillance of CDI. Using a standard set of 25 different C. difficile PCR ribotypes a database was made by different mass spectra recorded in the SARAMIS software (AnagnosTec, Zossen, Germany). The database was validated with 355 C. difficile strains belonging to 29 different PCR ribotypes collected prospectively from all submitted feces samples in 2009. The most frequent PCR ribotypes were type 001 (70%), 027 (4.8%) and 078/126 (4.7%). All three types were recognized by MALDI-TOF MS. We conclude that an extended MALDI-TOF system was capable to recognize specific markers for ribotypes 001, 027 and 078/126 allowing an effective identification of these strains. PMID:21503840

Reil, M; Erhard, M; Kuijper, E J; Kist, M; Zaiss, H; Witte, W; Gruber, H; Borgmann, S

2011-11-01

267

In situ identification of plant-invasive bacteria with MALDI-TOF mass spectrometry.  

PubMed

Rhizobia form a disparate collection of soil bacteria capable of reducing atmospheric nitrogen in symbiosis with legumes. The study of rhizobial populations in nature involves the collection of large numbers of nodules found on roots or stems of legumes, and the subsequent typing of nodule bacteria. To avoid the time-consuming steps of isolating and cultivating nodule bacteria prior to genotyping, a protocol of strain identification based on the comparison of MALDI-TOF MS spectra was established. In this procedure, plant nodules were considered as natural bioreactors that amplify clonal populations of nitrogen-fixing bacteroids. Following a simple isolation procedure, bacteroids were fingerprinted by analysing biomarker cellular proteins of 3 to 13 kDa using Matrix Assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) mass spectrometry. In total, bacteroids of more than 1,200 nodules collected from roots of three legumes of the Phaseoleae tribe (cowpea, soybean or siratro) were examined. Plants were inoculated with pure cultures of a slow-growing Bradyrhizobium japonicum strain G49, or either of two closely related and fast-growing Sinorhizobium fredii strains NGR234 and USDA257, or with mixed inoculants. In the fully automatic mode, correct identification of bacteroids was obtained for >97% of the nodules, and reached 100% with a minimal manual input in processing of spectra. These results showed that MALDI-TOF MS is a powerful tool for the identification of intracellular bacteria taken directly from plant tissues. PMID:22615938

Ziegler, Dominik; Mariotti, Anna; Pflüger, Valentin; Saad, Maged; Vogel, Guido; Tonolla, Mauro; Perret, Xavier

2012-01-01

268

In Situ Identification of Plant-Invasive Bacteria with MALDI-TOF Mass Spectrometry  

PubMed Central

Rhizobia form a disparate collection of soil bacteria capable of reducing atmospheric nitrogen in symbiosis with legumes. The study of rhizobial populations in nature involves the collection of large numbers of nodules found on roots or stems of legumes, and the subsequent typing of nodule bacteria. To avoid the time-consuming steps of isolating and cultivating nodule bacteria prior to genotyping, a protocol of strain identification based on the comparison of MALDI-TOF MS spectra was established. In this procedure, plant nodules were considered as natural bioreactors that amplify clonal populations of nitrogen-fixing bacteroids. Following a simple isolation procedure, bacteroids were fingerprinted by analysing biomarker cellular proteins of 3 to 13 kDa using Matrix Assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) mass spectrometry. In total, bacteroids of more than 1,200 nodules collected from roots of three legumes of the Phaseoleae tribe (cowpea, soybean or siratro) were examined. Plants were inoculated with pure cultures of a slow-growing Bradyrhizobium japonicum strain G49, or either of two closely related and fast-growing Sinorhizobium fredii strains NGR234 and USDA257, or with mixed inoculants. In the fully automatic mode, correct identification of bacteroids was obtained for >97% of the nodules, and reached 100% with a minimal manual input in processing of spectra. These results showed that MALDI-TOF MS is a powerful tool for the identification of intracellular bacteria taken directly from plant tissues. PMID:22615938

Pflüger, Valentin; Saad, Maged; Vogel, Guido; Tonolla, Mauro; Perret, Xavier

2012-01-01

269

Matrix-assisted laser desorption/ionisation, time-of-flight mass spectrometry in genomics research.  

PubMed

The beginning of this millennium has seen dramatic advances in genomic research. Milestones such as the complete sequencing of the human genome and of many other species were achieved and complemented by the systematic discovery of variation at the single nucleotide (SNP) and whole segment (copy number polymorphism) level. Currently most genomics research efforts are concentrated on the production of whole genome functional annotations, as well as on mapping the epigenome by identifying the methylation status of CpGs, mainly in CpG islands, in different tissues. These recent advances have a major impact on the way genetic research is conducted and have accelerated the discovery of genetic factors contributing to disease. Technology was the critical driving force behind genomics projects: both the combination of Sanger sequencing with high-throughput capillary electrophoresis and the rapid advances in microarray technologies were keys to success. MALDI-TOF MS-based genome analysis represents a relative newcomer in this field. Can it establish itself as a long-term contributor to genetics research, or is it only suitable for niche areas and for laboratories with a passion for mass spectrometry? In this review, we will highlight the potential of MALDI-TOF MS-based tools for resequencing and for epigenetics research applications, as well as for classical complex genetic studies, allele quantification, and quantitative gene expression analysis. We will also identify the current limitations of this approach and attempt to place it in the context of other genome analysis technologies. PMID:16895448

Ragoussis, Jiannis; Elvidge, Gareth P; Kaur, Kulvinder; Colella, Stefano

2006-07-01

270

Mass Spectrometry-Based Metabolite Profiling in the Mouse Liver following Exposure to Ultraviolet B Radiation  

PubMed Central

Although many studies have been performed on the effects of ultraviolet (UV) radiation on the skin, only a limited number of reports have investigated these effects on non-skin tissue. This study aimed to describe the metabolite changes in the liver of hairless mice following chronic exposure to UVB radiation. We did not observe significant macroscopic changes or alterations in hepatic cholesterol and triglyceride levels in the liver of UVB-irradiated mice, compared with those for normal mice. In this study, we detected hepatic metabolite changes by UVB exposure and identified several amino acids, fatty acids, nucleosides, carbohydrates, phospholipids, lysophospholipids, and taurine-conjugated cholic acids as candidate biomarkers in response to UVB radiation in the mouse liver by using various mass spectrometry (MS)-based metabolite profiling including ultra-performance liquid chromatography-quadrupole time-of-flight (TOF)-MS, gas chromatography-TOF-MS and nanomate LTQ-MS. Glutamine exhibited the most dramatic change with a 5-fold increase in quantity. The results from altering several types of metabolites suggest that chronic UVB irradiation may impact significantly on major hepatic metabolism processes, despite the fact that the liver is not directly exposed to UVB radiation. MS-based metabolomic approach for determining regulatory hepatic metabolites following UV irradiation will provide a better understanding of the relationship between internal organs and UV light. PMID:25275468

Park, Hye Min; Shon, Jong Cheol; Lee, Mee Youn; Liu, Kwang-Hyeon; Kim, Jeong Kee; Lee, Sang Jun; Lee, Choong Hwan

2014-01-01

271

Analysis of anthocyanins in red onion using capillary electrophoresis-time of flight-mass spectrometry.  

PubMed

For the first time, a capillary electrophoresis-time of flight-mass spectrometry analysis method for detecting anthocyanins in red onion was developed. The analysis method included the use of silica capillaries coated with poly-LA 313 (polycationic amine-containing polymer) and an MS-compatible volatile background electrolyte (BGE). The method was environmentally friendly and sensitive; and its rapidness combined with an acidic BGE helped in preventing anthocyanin degradation. By using high-resolution TOF-MS with pre-run tuning of masses, low mass errors were achieved in the determination of conjugated anthocyanins in red onion, and a simultaneous up-front fragmentation provided confirmation of the aglycon backbone for their secure identification. Most anthocyanins (at least seven out of ten) known in red onion from the literature were found, as well as one new for this matrix. PMID:18512683

Petersson, Erik V; Puerta, Angel; Bergquist, Jonas; Turner, Charlotta

2008-06-01

272

Measurement of lysine-specific demethylase-1 activity in the nuclear extracts by flow-injection based time-of-flight mass spectrometry  

PubMed Central

Lysine-specific demethylase 1 (LSD1/KDM1A), a histone-modifying enzyme, is upregulated in many cancers, especially in neuroblastoma, breast cancer and hepatoma. We have established a simple method to measure LSD1 activity using a synthetic N-terminal 21-mer peptide of histone H3, which is dimethylated at Lys-4 (H3K4me2). After the enzyme reaction, a substrate of H3K4me2 and two demethylated products, H3K4me1 and H3K4me0, were quantitatively determined by flow injection time-of-flight mass spectrometry (FI-TOF/MS). By using recombinant human LSD1, a nonlinear fitting simulation of the data obtained by FI-TOF/MS produced typical consecutive-reaction kinetics. Apparent Km and kcat values of hLSD1 for the first and second demethylation reactions were found to be in the range of reported values. Tranylcypromine was shown to inhibit LSD1 activity with an IC50 of 6.9 µM for the first demethylation reaction and 5.8 µM for the second demethylation reaction. The FI-TOF/MS assay revealed that the endogenous LSD1 activity was higher in the nuclear extracts of SH-SY5Y cells than in HeLa or PC-3 cells, and this is in accordance with the immunoblotting data using an anti-LSD1 antibody. A simple, straightforward FI-TOF/MS assay is described to efficiently measure LSD1 activity in the nuclear extracts of cultured cells. PMID:25759518

Sakane, Chiharu; Ohta, Hiromichi; Shidoji, Yoshihiro

2015-01-01

273

Matrix-assisted laser desorption ionization time of flight mass spectrometry and diagnostic testing for prosthetic joint infection in the clinical microbiology laboratory.  

PubMed

Identification of pathogen(s) associated with prosthetic joint infection (PJI) is critical for patient management. Historically, many laboratories have not routinely identified organisms such as coagulase-negative staphylococci to the species level. The advent of matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) has enhanced clinical laboratory capacity for accurate species-level identification. The aim of this study was to describe the species-level identification of microorganisms isolated from periprosthetic tissue and fluid specimens using MALDI-TOF MS alongside other rapid identification tests in a clinical microbiology laboratory. Results of rapid identification of bacteria isolated from periprosthetic joint fluid and/or tissue specimens were correlated with clinical findings at Mayo Clinic, Rochester, Minnesota, between May 2012 and May 2013. There were 178 PJI and 82 aseptic failure (AF) cases analyzed, yielding 770 organisms (median, 3/subject; range, 1-19/subject). MALDI-TOF MS was employed for the identification of 455 organisms (59%) in 197 subjects (123 PJIs and 74 AFs), with 89% identified to the species level using this technique. Gram-positive bacteria accounted for 68% and 93% of isolates in PJI and AF, respectively. However, the profile of species associated with infection compared to specimen contamination differed. Staphylococcus aureus and Staphylococcus caprae were always associated with infection, Staphylococcus epidermidis and Staphylococcus lugdunensis were equally likely to be a pathogen or a contaminant, whereas the other coagulase-negative staphylococci were more frequently contaminants. Most streptococcal and Corynebacterium isolates were pathogens. The likelihood that an organism was a pathogen or contaminant differed with the prosthetic joint location, particularly in the case of Propionibacterium acnes. MALDI-TOF MS is a valuable tool for the identification of bacteria isolated from patients with prosthetic joints, providing species-level identification that may inform culture interpretation of pathogens versus contaminants. PMID:25533615

Peel, Trisha N; Cole, Nicolynn C; Dylla, Brenda L; Patel, Robin

2015-03-01

274

Dual polarity accurate mass calibration for electrospray ionization and matrix-assisted laser desorption/ionization mass spectrometry using maltooligosaccharides.  

PubMed

In view of the fact that memory effects associated with instrument calibration hinder the use of many mass-to-charge (m/z) ratios and tuning standards, identification of robust, comprehensive, inexpensive, and memory-free calibration standards is of particular interest to the mass spectrometry community. Glucose and its isomers are known to have a residue mass of 162.05282Da; therefore, both linear and branched forms of polyhexose oligosaccharides possess well-defined masses, making them ideal candidates for mass calibration. Using a wide range of maltooligosaccharides (MOSs) derived from commercially available beers, ions with m/z ratios from approximately 500 to 2500Da or more have been observed using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and time-of-flight mass spectrometry (TOF-MS). The MOS mixtures were further characterized using infrared multiphoton dissociation (IRMPD) and nano-liquid chromatography/mass spectrometry (nano-LC/MS). In addition to providing well-defined series of positive and negative calibrant ions using either electrospray ionization (ESI) or matrix-assisted laser desorption/ionization (MALDI), the MOSs are not encumbered by memory effects and, thus, are well-suited mass calibration and instrument tuning standards for carbohydrate analysis. PMID:18655765

Clowers, Brian H; Dodds, Eric D; Seipert, Richard R; Lebrilla, Carlito B

2008-10-15

275

Microorganism Identification Based On MALDI-TOF-MS Fingerprints  

NASA Astrophysics Data System (ADS)

Advances in MALDI-TOF mass spectrometry have enabled the ­development of a rapid, accurate and specific method for the identification of bacteria directly from colonies picked from culture plates, which we have named the MALDI Biotyper. The picked colonies are placed on a target plate, a drop of matrix solution is added, and a pattern of protein molecular weights and intensities, "the protein fingerprint" of the bacteria, is produced by the MALDI-TOF mass spectrometer. The obtained protein mass fingerprint representing a molecular signature of the microorganism is then matched against a database containing a library of previously measured protein mass fingerprints, and scores for the match to every library entry are produced. An ID is obtained if a score is returned over a pre-set threshold. The sensitivity of the techniques is such that only approximately 104 bacterial cells are needed, meaning that an overnight culture is sufficient, and the results are obtained in minutes after culture. The improvement in time to result over biochemical methods, and the capability to perform a non-targeted identification of bacteria and spores, potentially makes this method suitable for use in the detect-to-treat timeframe in a bioterrorism event. In the case of white-powder samples, the infectious spore is present in sufficient quantity in the powder so that the MALDI Biotyper result can be obtained directly from the white powder, without the need for culture. While spores produce very different patterns from the vegetative colonies of the corresponding bacteria, this problem is overcome by simply including protein fingerprints of the spores in the library. Results on spores can be returned within minutes, making the method suitable for use in the "detect-to-protect" timeframe.

Elssner, Thomas; Kostrzewa, Markus; Maier, Thomas; Kruppa, Gary

276

An optimized protein in-gel digest method for reliable proteome characterization by MALDI-TOF-MS analysis.  

PubMed

Human lung epithelial cells (A549) were used as a model to develop a reliable proteome characterization method by peptide mass fingerprinting (PMF). Lung cell lysate proteins and protein standards were separated by 2D-gel electrophoresis, stained with Coomassie blue, gel plugs were subjected to commonly adapted as well as optimized in-gel digestion/sample preparation methods. Samples were analyzed by MALDI-TOF-MS. Optimization parameters included, use of NH(4)OAc in destaining and in-gel digestion buffers, detergent/salt removal prior to in-gel digestion, use of solvents of varying polarities (0%, 30%, 60% ACN containing 0.1% TFA) to improve peptide recoveries, matrix composition (alpha-cyano-4-hydroxycinamic acid-organic solvent combinations) and on-target salt removal. This led to enhanced mass spectral information and a sensitivity gain in the order of 6-10 fold compared to that of common procedures, yielding reliable, unambiguous protein identification with femtomol protein sensitivity by Autoflex MALDI-TOF-MS. Triplicate analyses by two analysts revealed consistent, wide range m/z values including in < 1200Da region by relieving matrix-exerted signal suppression, requiring one trial to obtain a unique protein identification with superior PMF results for the optimized method. Analyses of ten A549 proteins in replicates using the optimized method yielded fast, reliable characterization, suggesting the potential application of this method in high-throughput protein identification by PMF. PMID:16168381

Kumarathasan, P; Mohottalage, S; Goegan, P; Vincent, R

2005-11-01

277

Nevan Krogan: Mass Spectrometry  

NSDL National Science Digital Library

This lecture from the iBioSeminars project, presented by Nevan Krogan of the Department of Cellular and Molecular Pharmacology at UC-San Francisco, covers mass spectrometry and its application to molecular biology. Mass spectrometry is a powerful tool for elucidating the elemental composition of a sample or molecule. More recently, it has been used to characterize biological material, in particular proteins and protein complexes, in a variety of organisms. This lecture will review the underlying principles of how a mass spectrometer works, discuss up to date instrumentation that is presently being used in the biological research setting and provide specific examples of how mass spectrometry is being used to reveal functional insight into different biological systems. The video runs 27:36 and can be downloaded in a number of formats: QuickTime, MP4, M4V, and PPT. The video can also be streamed through YouTube or iTunes U.

Krogan, Nevan

278

Mass Spectrometry for the Masses  

ERIC Educational Resources Information Center

A simple, qualitative experiment is developed for implementation, where the gas chromatography-mass spectrometry (GC-MS) plays an important role, into the laboratory curriculum of a chemistry course designed for nonscience majors. This laboratory experiment is well suited for the students as it helps them to determine the validity of their…

Persinger, Jared D.; Hoops, Geoffrey, C.; Samide, Michael J.

2004-01-01

279

Mass Spectrometry Primer  

NSDL National Science Digital Library

This website developed by Waters Corporation provides a brief primer on mass spectrometry which includes information on instrumentation, a discussion of mass accuracy, resolution, and LC-MS. As such the site should be a valuable resource for both students and faculty.

280

Application of MALDI-TOF MS for requalification of a Candida clinical isolates culture collection  

PubMed Central

Microbial culture collections underpin biotechnology applications and are important resources for clinical microbiology by supplying reference strains and/or performing microbial identifications as a service. Proteomic profiles by MALDI-TOF MS have been used for Candida spp. identification in clinical laboratories and demonstrated to be a fast and reliable technique for the routine identification of pathogenic yeasts. The main aim of this study was to apply MALDI-TOF MS combined with classical phenotypic and molecular approaches to identify Candida clinical isolates preserved from 1 up to 52 years in a Brazilian culture collection and assess its value for the identification of yeasts preserved in this type of collections. Forty Candida spp. clinical isolates were identified by morphological and biochemical analyses. Identifications were also performed by the new proteomic approach based on MALDI-TOF MS. Results demonstrated 15% discordance when compared with morphological and biochemical analyses. Discordant isolates were analysed by ITS sequencing, which confirmed the MALDI-TOF MS identifications and these strains were renamed in the culture collection catalogue. In conclusion, proteomic profiles by MALDI-TOF MS represents a rapid and reliable method for identifying clinical Candida species preserved in culture collections and may present clear benefits when compared with the performance of existing daily routine methods applied at health centres and hospitals. PMID:25242936

Lima-Neto, Reginaldo; Santos, Cledir; Lima, Nelson; Sampaio, Paula; Pais, Célia; Neves, Rejane P.

2014-01-01

281

UPLC Q-TOF/MS-Based Metabolic Profiling of Urine Reveals the Novel Antipyretic Mechanisms of Qingkailing Injection in a Rat Model of Yeast-Induced Pyrexia  

PubMed Central

Fever is one of the most common clinical symptoms of many diseases. Qingkailing (QKL) injection is widely used in China as a clinical emergency medicine due to its good antipyretic effects. It is a herbal formula which is composed by eight kinds of traditional Chinese medicines (TCM). As a kind of typical multiple constituents and multiple actions of TCM, it is very difficult to elaborate the antipyretic mechanism by conventional pharmacological method. Metabonomics technique provides beneficial tool for this challenge. In this study, an ultra performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC Q-TOF/MS) metabonomics method was developed to explore the changing process of biochemical substances in rats of yeast-induced pyrexia. Partial least squares discriminate analysis (PLS-DA) was used to distinguish the normal control group, the pyrexia model group, and the pyrexia model group treated by QKL injection. The potential biomarkers related to pyrexia were confirmed and identified. MetPA was used to find the possible metabolic pathways. The results indicated that the antipyretic effect of QKL injection on yeast-induced pyrexia rats was performed by repairing the perturbed metabolism of amino acids. PMID:23840267

Gao, Xiaoyan; Guo, Mingxing; Peng, Long; Zhao, Baosheng; Su, Jiankun; Liu, Haiyu; Zhang, Li; Bai, Xu; Qiao, Yanjiang

2013-01-01

282

Relative quantitation of glycosylation variants by stable isotope labeling of enzymatically released N-glycans using [12C]/[13C] aniline and ZIC-HILIC-ESI-TOF-MS.  

PubMed

Glycan reductive isotope labeling (GRIL) using [(12)C]- and [(13)C]-coded aniline was used for relative quantitation of N-glycans. In a first step, the labeling method by reductive amination was optimized for this reagent. It could be demonstrated that selecting aniline as limiting reactant and using the reductant in excess is critical for achieving high derivatization yields (over 95 %) and good reproducibility (relative standard deviations ?1-5 % for major and ?5-10 % for minor N-glycans). In a second step, zwitterionic-hydrophilic interaction liquid chromatography in capillary columns coupled to electrospray mass spectrometry with time-of-flight analyzer (?ZIC-HILIC-ESI-TOF-MS) was applied for the analysis of labeled N-glycans released from intact glycoproteins. Ovalbumin, bovine ?1-acid-glycoprotein and bovine fetuin were used as test glycoproteins to establish and evaluate the methodology. Excellent separation of isomeric N-glycans and reproducible quantitation via the extracted ion chromatograms indicate a great potential of the proposed methodology for glycoproteomic analysis and for reliable relative quantitation of glycosylation variants in biological samples. PMID:23846592

Giménez, Estela; Sanz-Nebot, Victòria; Rizzi, Andreas

2013-09-01

283

Isolation and identification of flavour peptides from Puffer fish (Takifugu obscurus) muscle using an electronic tongue and MALDI-TOF/TOF MS/MS.  

PubMed

To clarify the key flavour peptides that account for the cooked taste of puffer fish, this study was performed to examine flavour peptides extracted from the flesh of puffer fish (Takifugu obscurus). Peptides fractions (P1, P2, P3, P4 and P5) were purified from an aqueous extract of T. obscurus muscle by ultrafiltration and Sephadex G-15 gel filtration chromatography (GFC). P2 was further fractionated into P2a, P2b, and P2c by reverse phase high performance liquid chromatography (RP-HPLC). Fraction P2b elicited umami and sweet taste. The amino acid sequence of P2b subfraction was identified as Tyr-Gly-Gly-Thr-Pro-Pro-Phe-Val (836.4Da) by matrix-assisted laser desorption/ionisation time of flight mass spectrometry (MALDI-TOF/TOF MS/MS). Hydrophilic amino acids residues Tyr, Gly, Gly, Thr, and Phe are likely to contribute to the umami and sweet taste of this octapeptide. The results of this study suggest this peptide is one of important components of the 'mellowness' and 'tenderness' taste of the T. obscurus. PMID:22953881

Zhang, Mei-Xiu; Wang, Xi-Chang; Liu, Yuan; Xu, Xing-Lian; Zhou, Guang-Hong

2012-12-01

284

Metabolic profiling study on potential toxicity and immunotoxicity-biomarker discovery in rats treated with cyclophosphamide using HPLC-ESI-IT-TOF-MS.  

PubMed

Despite the recent advances in understanding toxicity mechanism of cyclophosphamide (CTX), the development of biomarkers is still essential. CTX-induced immunotoxicity in rats by a metabonomics approach was investigated using high-performance liquid chromatography coupled with ion trap time-of-flight mass spectrometry (HPLC-ESI-IT-TOF-MS). The rats were orally administered CTX (30?mg/kg/day) for five consecutive days, and on the fifth day samples of urine, thymus and spleen were collected and analyzed. A significant difference in metabolic profiling was observed between the CTX-treated group and the control group by partial least squares-discriminant analysis (PLS-DA), which indicated that metabolic disturbances of immunotoxicity in CTX-treated rats had occurred. One potential biomarker in spleen, three in urine and three in thymus were identified. It is suggested that the CTX-toxicity mechanism may involve the modulation of tryptophan metabolism, phospholipid metabolism and energy metabolism. This research can help to elucidate the CTX-influenced pathways at a low dose and can further help to indicate the patients' pathological status at earlier stages of toxicological progression after drug administration. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25322901

Li, Jing; Lin, Wensi; Lin, Weiwei; Xu, Peng; Zhang, Jianmei; Yang, Haisong; Ling, Xiaomei

2015-05-01

285

Characterization of forced degradation products of ketorolac tromethamine using LC/ESI/Q/TOF/MS/MS and in silico toxicity prediction.  

PubMed

Ketorolac, a nonsteroidal anti-inflammatory drug, was subjected to forced degradation studies as per International Conference on Harmonization guidelines. A simple, rapid, precise, and accurate high-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (LC/ESI/Q/TOF/MS/MS) method has been developed for the identification and structural characterization of stressed degradation products of ketorolac. The drug was found to degrade in hydrolytic (acidic, basic, and neutral), photolytic (acidic, basic, and neutral solution), and thermal conditions, whereas the solid form of the drug was found to be stable under photolytic conditions. The method has shown adequate separation of ketorolac tromethamine and its degradation products on a Grace Smart C-18 (250?mm?×?4.6?mm i.d., 5?µm) column using 20?mM ammonium formate (pH?=?3.2): acetonitrile as a mobile phase in gradient elution mode at a flow rate of 1.0?ml/min. A total of nine degradation products were identified and characterized by LC/ESI/MS/MS. The most probable mechanisms for the formation of degradation products have been proposed on the basis of a comparison of the fragmentation of the [M?+?H](+) ions of ketorolac and its degradation products. In silico toxicity of the drug and degradation products was investigated by using topkat and derek softwares. The method was validated in terms of specificity, linearity, accuracy, precision, and robustness as per International Conference on Harmonization guidelines. PMID:24809899

Kalariya, Pradipbhai D; Raju, B; Borkar, Roshan M; Namdev, Deepak; Gananadhamu, S; Nandekar, Prajwal P; Sangamwar, Abhay T; Srinivas, R

2014-05-01

286

LC-ESI-TOF-MS identification of bioactive secondary metabolites involved in the antioxidant, anti-inflammatory and anticancer activities of the edible halophyte Zygophyllum album Desf.  

PubMed

In this work, liquid chromatography coupled to electrospray time-of-flight mass spectrometry (LC-ESI-TOF-MS) has been applied to screen bioactive metabolites in shoot extract of the medicinal halophyte Zygophyllum album. Among 10 compounds identified (saponins, flavonoids and sterols) five were reported for the first time in Z. album. Furthermore, novel biological activities of hexane, dichloromethane and methanolic extracts were assessed. Results showed that methanolic extract exhibit the highest antioxidant activity using in vitro ORAC test and anti-inflammatory activity, inhibiting by 84.8% NO release in RAW264.7 macrophages. However, dichloromethane extract proved the utmost antioxidant activity in cell (WS1) based-assay (IC50=57 ?g/ml) and interesting anticancer capacity against human lung carcinoma (A-549) and colon adenocarcinoma (DLD-1) cells (IC50=37 and 48 ?g/ml, respectively). These findings can be attributed to the presence of triterpenes, flavonoids and sterols in Z. album, which are widely known as powerful antioxidants and used in various industrial fields. PMID:23561211

Ksouri, Wided Megdiche; Medini, Faten; Mkadmini, Khaoula; Legault, Jean; Magné, Christian; Abdelly, Chedly; Ksouri, Riadh

2013-08-15

287

Metabolomics of adherent mammalian cells by capillary electrophoresis-mass spectrometry: HT-29 cells as case study.  

PubMed

In this work, the optimization of an effective protocol for cell metabolomics is described with special emphasis in the sample preparation and subsequent analysis of intracellular metabolites from adherent mammalian cells by capillary electrophoresis-mass spectrometry. As case study, colon cancer HT-29 cells, a human cell model to investigate colon cancer, are employed. The feasibility of the whole method for cell metabolomics is demonstrated via a fast and sensitive profiling of the intracellular metabolites HT-29 cells by capillary electrophoresis-time-of-flight mass spectrometry (CE-TOF MS). The suitability of this methodology is further corroborated through the examination of the metabolic changes in the polyamines pathway produced in colon cancer HT-29 cells by difluoromethylornithine (DFMO), a known potent ornithine decarboxylase inhibitor. The selection of the optimum extraction conditions allowed a higher sample volume injection that led to an increase in CE-TOF MS sensitivity. Following a non-targeted metabolomics approach, 10 metabolites (namely, putrescine, ornithine, gamma-aminobutyric acid (GABA), oxidized and reduced glutathione, 5'-deoxy-5'-(methylthio)adenosine, N-acetylputrescine, cysteinyl-glycine, spermidine and an unknown compound) were found to be significantly altered by DFMO (p<0.05) in HT-29 cells. In addition to the effect of DFMO on polyamine metabolism, minor modifications of other metabolic pathways (e.g., related to intracellular thiol redox state) were observed. PMID:25818703

Ibáñez, Clara; Simó, Carolina; Valdés, Alberto; Campone, Luca; Piccinelli, Anna Lisa; García-Cañas, Virginia; Cifuentes, Alejandro

2015-06-10

288

The sensitivity of direct identification from positive BacT/ALERT™ (bioMérieux) blood culture bottles by matrix-assisted laser desorption ionization time-of-flight mass spectrometry is low.  

PubMed

Recently, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been presented as a novel method for the direct identification of bacteria from positive blood culture bottles. The rate of the MALDI TOF MS-based identification in the present study from positive BacT/ALERT (bioMérieux, Marcy l'Etoile, France) blood culture bottles was 30%, which is far below the previously reported sensitivities using the BACTEC (Becton Dickinson, Franklin Lakes, NJ, USA) system. We also found evidence that the Biotyper algorithm did not identify a second pathogen in cases of positive BacT/ALERT blood culture bottles containing two different species. PMID:20370799

Szabados, F; Michels, M; Kaase, M; Gatermann, S

2011-02-01

289

Rapid, sensitive, and validated UPLC/Q-TOF-MS method for quantitative determination of vasicine in Adhatoda vasica and its in vitro culture  

PubMed Central

Background: Adhatoda vasica a perennial herb has been used in Ayurvedic and Unani system of medicines since last 2000 years and has been employed for the treatment of respiratory tract ailments. Objective: To develop and validate new, rapid, and highly sensitive high throughput ultra-performance liquid chromatography/quadrupole-time-of-flight mass-spectrometry (UPLC/Q-TOF-MS) method for the quantitative estimation of vasicine in the leaves and to establish in vitro cultures of Adhatoda vasica for production of vasicine. Materials and Methods: The chromatographic separation was achieved on a Waters ACQUITY UPLC™ BEH C8 (100.0 × 2.1 mm; 1.7 ?m) column packing using isocratic mobile phase consisting of acetonitrile: 20 mM ammonium acetate (90:10; v/v) in a multiple reactions monitoring mode using the transitions m/z 189.09 ? 171.08 for vasicine. Results: The vasicine was eluted at 2.58 ± 0.05 min and established a dynamic range of linearity over the concentration range of 1-1000 ng/ml (r2 = 0.999 ± 0.0005). The lower limit of detection and quantification was 0.68 and 1.0 ng/ml, respectively. There was no significant difference observed in the content of vasicine (0.92-1.04%w/w) among the eleven samples collected from different locations of India. The in vitro cultures developed showed that addition of extra 28 mM KNO3 and 100 mM NaCl in MS medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) + benzyladenine (BA) + indole acetic acid (IAA) (1 ppm each) produces faster biomass and higher amount of quinazoline alkaloids. Conclusion: Rapid, efficient, and sensitive UPLC/Q-TOF-MS method was developed for the estimation of vasicine and an efficient protocol for development of in vitro cultures was proposed, which can be used at large scale for industrial production of vasicine using bioreactors. PMID:24914304

Madhukar, Garg; Tamboli, Ennus Tajuddin; Rabea, Parveen; Ansari, S. H.; Abdin, M. Z.; Sayeed, Ahmad

2014-01-01

290

Analysis of nonderivatized neutral and sialylated oligosaccharides by electrospray mass spectrometry.  

PubMed

An HPLC/MS method has been developed that allows rapid, direct analysis of underivatized sialylated as well as neutral oligosaccharides. The method involves the separation of oligosaccharides from salts and proteins using RP-HPLC with a formic acid/acetonitrile/water mobile phase system and on-line electrospray mass spectrometry analysis in the positive ion mode. Under the solution conditions employed, both neutral and acidic (sialylated) oligosaccharides are protonated and therefore detected. In contrast to MALDI-TOF MS, no loss of sialic acid is observed when operating in the positive ion mode. Furthermore, the capability of this method to provide quantitative estimates of the relative abundance of each oligosaccharide mass has been demonstrated using fetuin as a model compound. PMID:10952540

Huang, L; Riggin, R M

2000-08-01

291

Laser Time-of-Flight Mass Spectrometry for Future In Situ Planetary Missions  

NASA Technical Reports Server (NTRS)

Laser desorption/ionization time-of-flight mass spectrometry (LD-TOF-MS) is a versatile, low-complexity instrument class that holds significant promise for future landed in situ planetary missions that emphasize compositional analysis of surface materials. Here we describe a 5kg-class instrument that is capable of detecting and analyzing a variety of analytes directly from rock or ice samples. Through laboratory studies of a suite of representative samples, we show that detection and analysis of key mineral composition, small organics, and particularly, higher molecular weight organics are well suited to this instrument design. A mass range exceeding 100,000 Da has recently been demonstrated. We describe recent efforts in instrument prototype development and future directions that will enhance our analytical capabilities targeting organic mixtures on primitive and icy bodies. We present results on a series of standards, simulated mixtures, and meteoritic samples.

Getty, S. A.; Brinckerhoff, W. B.; Cornish, T.; Ecelberger, S. A.; Li, X.; Floyd, M. A. Merrill; Chanover, N.; Uckert, K.; Voelz, D.; Xiao, X.; Tawalbeh, R.; Glenar, D.; Elsila, J. E.; Callahan, M.

2012-01-01

292

Understanding Chemistry: Mass Spectrometry  

NSDL National Science Digital Library

This website, which is part of a larger project "ChemGuide" provides a nice introduction to mass spectrometry that is suitable for use by introductory analytical chemistry students. Content includes an introduction to the instrumentation, explanation of fragmentation and how it can be used to identify compound structure, the origin of the M+ and (M+1)+ peaks. Each section is succinct, well written and provides a simple example. As such the site should be useful to faculty introducing mass spectrometry in the analytical classroom and to chemistry students.

Clark, Jim

293

Rapid Identification and Typing of Listeria Species by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry? †  

PubMed Central

Listeria monocytogenes is a food-borne pathogen that is the causative agent of human listeriosis, an opportunistic infection that primarily infects pregnant women and immunologically compromised individuals. Rapid, accurate discrimination between Listeria strains is essential for appropriate therapeutic management and timely intervention for infection control. A rapid method involving matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) that shows promise for identification of Listeria species and typing and even allows for differentiation at the level of clonal lineages among pathogenic strains of L. monocytogenes is presented. A total of 146 strains of different Listeria species and serotypes as well as clinical isolates were analyzed. The method was compared with the pulsed-field gel electrophoresis analysis of 48 Listeria strains comprising L. monocytogenes strains isolated from food-borne epidemics and sporadic cases, isolates representing different serotypes, and a number of Listeria strains whose genomes have been completely sequenced. Following a short inactivation/extraction procedure, cell material from a bacterial colony was deposited on a sample target, dried, overlaid with a matrix necessary for the MALDI process, and analyzed by MALDI-TOF MS. This technique examines the chemistry of major proteins, yielding profile spectra consisting of a series of peaks, a characteristic “fingerprint” mainly derived from ribosomal proteins. Specimens can be prepared in a few minutes from plate or liquid cultures, and a spectrum can be obtained within 1 minute. Mass spectra derived from Listeria isolates showed characteristic peaks, conserved at both the species and lineage levels. MALDI-TOF MS fingerprinting may have potential for Listeria identification and subtyping and may improve infection control measures. PMID:18606788

Barbuddhe, Sukhadeo B.; Maier, Thomas; Schwarz, Gerold; Kostrzewa, Markus; Hof, Herbert; Domann, Eugen; Chakraborty, Trinad; Hain, Torsten

2008-01-01

294

A rapid MALDI-TOF mass spectrometry workflow for Drosophila melanogaster differential neuropeptidomics  

PubMed Central

Background Neuropeptides are a diverse category of signaling molecules in the nervous system regulating a variety of processes including food intake, social behavior, circadian rhythms, learning, and memory. Both the identification and functional characterization of specific neuropeptides are ongoing fields of research. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis of nervous tissues from a variety of organisms allows direct detection and identification of neuropeptides. Here, we demonstrate an analysis workflow that allows for the detection of differences in specific neuropeptides amongst a variety of neuropeptides being simultaneously measured. For sample preparation, we describe a straight-forward and rapid (minutes) method where individual adult Drosophila melanogaster brains are analyzed. Using a MATLAB-based data analysis workflow, also compatible with MALDI-TOF mass spectra obtained from other sample preparations and instrumentation, we demonstrate how changes in neuropeptides levels can be detected with this method. Results Over fifty isotopically resolved ion signals in the peptide mass range are reproducibly observed across experiments. MALDI-TOF MS profile spectra were used to statistically identify distinct relative differences in organ-wide endogenous levels of detected neuropeptides between biological conditions. In particular, three distinct levels of a particular neuropeptide, pigment dispersing factor, were detected by comparing groups of preprocessed spectra obtained from individual brains across three different D. melanogaster strains, each of which express different amounts of this neuropeptide. Using the same sample preparation, MALDI-TOF/TOF tandem mass spectrometry confirmed that at least 14 ion signals observed across experiments are indeed neuropeptides. Among the identified neuropeptides were three products of the neuropeptide-like precursor 1 gene previously not identified in the literature. Conclusions Using MALDI-TOF MS and preprocessing/statistical analysis, changes in relative levels of a particular neuropeptide in D. melanogaster tissue can be statistically detected amongst a variety of neuropeptides. While the data analysis methods should be compatible with other sample preparations, the presented sample preparation method was sufficient to identify previously unconfirmed D. melanogaster neuropeptides. PMID:24373546

2013-01-01

295

Comparison of low molecular weight glutenin subunits identified by SDS-PAGE, 2-DE, MALDI-TOF-MS and PCR in common wheat  

PubMed Central

Background Low-molecular-weight glutenin subunits (LMW-GS) play a crucial role in determining end-use quality of common wheat by influencing the viscoelastic properties of dough. Four different methods - sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), two-dimensional gel electrophoresis (2-DE, IEF × SDS-PAGE), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and polymerase chain reaction (PCR), were used to characterize the LMW-GS composition in 103 cultivars from 12 countries. Results At the Glu-A3 locus, all seven alleles could be reliably identified by 2-DE and PCR. However, the alleles Glu-A3e and Glu-A3d could not be routinely distinguished from Glu-A3f and Glu-A3g, respectively, based on SDS-PAGE, and the allele Glu-A3a could not be differentiated from Glu-A3c by MALDI-TOF-MS. At the Glu-B3 locus, alleles Glu-B3a, Glu-B3b, Glu-B3c, Glu-B3g, Glu-B3h and Glu-B3j could be clearly identified by all four methods, whereas Glu-B3ab, Glu-B3ac, Glu-B3ad could only be identified by the 2-DE method. At the Glu-D3 locus, allelic identification was problematic for the electrophoresis based methods and PCR. MALDI-TOF-MS has the potential to reliably identify the Glu-D3 alleles. Conclusions PCR is the simplest, most accurate, lowest cost, and therefore recommended method for identification of Glu-A3 and Glu-B3 alleles in breeding programs. A combination of methods was required to identify certain alleles, and would be especially useful when characterizing new alleles. A standard set of 30 cultivars for use in future studies was chosen to represent all LMW-GS allelic variants in the collection. Among them, Chinese Spring, Opata 85, Seri 82 and Pavon 76 were recommended as a core set for use in SDS-PAGE gels. Glu-D3c and Glu-D3e are the same allele. Two new alleles, namely, Glu-D3m in cultivar Darius, and Glu-D3n in Fengmai 27, were identified by 2-DE. Utilization of the suggested standard cultivar set, seed of which is available from the CIMMYT and INRA Clermont-Ferrand germplasm collections, should also promote information sharing in the identification of individual LMW-GS and thus provide useful information for quality improvement in common wheat. PMID:20573275

2010-01-01

296

Immunocytochemical and molecular data guide peptide identification by mass spectrometry: orcokinin and orcomyotropin-related peptides in the stomatogastric nervous system of several crustacean species.  

PubMed

In order to identify new orcokinin and orcomyotropin-related peptides in crustaceans, molecular and immunocytochemical data were combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). In the crayfish Procambarus clarkii, four orcokinins and an orcomyotropin-related peptide are present on the precursor. Because these peptides are highly conserved, we assumed that other species have an identical number of peptides. To identify the peptides, immunocytochemistry was used to localize the regions of the stomatogastric nervous system in which orcokinins are predominantly present. One of the regions predominantly containing orcokinins was a previously undescribed olive-shaped neuropil region within the commissural ganglia of the lobsters Homarus americanus and Homarus gammarus. MALDI-TOF MS on these regions identified peptide masses that always occur together with the known orcokinins. Seven peptide ions occurred together in the peptide massspectra of the lobsters. Mass spectrometric fragmentation by MALDI-MS post-source decay (PSD) and electrospray ionization quadrupole time-of-flight mass spectrometry (ESI Q-TOF MS) collision-induced dissociation (CID) were used in the identification of six of these masses, either as orcokinins or as orcomyotropin-related peptides and revealed three hitherto unknown peptide variants, two of which are [His13]-orcokinin ([M+H]+ = 1540.8 Da) and an orcomyotropin-related peptide FDAFTTGFGHN ([M+H]+ = 1213.5 Da). The mass of the third previously unknown orcokinin variant corresponded to that of an identified orcokinin, but PSD fragmentation did not support the suggested amino acid sequence. CID analysis allowed partial de novo sequencing of this peptide. In the crab Cancer pagurus, five orcokinins and an orcomyotropin-related peptide were unambigously identified, including the previously unknown peptide variant [Ser9-Val13]-orcokinin ([M+H]+ = 1532.8 Da). PMID:14528921

Skiebe, P; Dreger, M; Börner, J; Meseke, M; Weckwerth, W

2003-07-01

297

Comparative study of laser induced breakdown spectroscopy and mass spectrometry for the analysis of cultural heritage materials  

NASA Astrophysics Data System (ADS)

Analysis by laser-induced breakdown spectroscopy (LIBS) is compared, on the basis of a hybrid experimental set-up, with laser ablation time-of-flight mass spectrometry (LA-TOF-MS) for the characterization of materials relevant to cultural heritage. The present study focuses on the analysis of selected paint materials such as lithopone, a white inorganic pigment, and two synthetic organic paint formulations, lemon yellow and phthalocyanine blue. Optical emission spectra, obtained by LIBS, lead to rapid, straightforward identification of the elemental content of the paint samples while mass spectra yield, additionally to elemental analysis, complementary isotopic analysis and, more importantly, enable detection of molecules and molecular fragments, permitting a more complete structural and compositional characterization of composite materials. Mass spectra were recorded either simultaneously with the optical emission ones, or sequentially. The latter was preferred for materials having significantly lower fluence threshold for desorption/ionization relative to plasma formation resulting to optimum mass resolution and minimal surface damage. In all, the results of this study demonstrate the advantages of instrumentally complementing LIBS with TOF-MS in relation to applications in cultural heritage materials analysis, with exciting prospects when laser ablation sampling can be carried out under ambient atmosphere.

Kokkinaki, O.; Mihesan, C.; Velegrakis, M.; Anglos, D.

2013-07-01

298

SELDI-TOF mass spectrometry of High-Density Lipoprotein  

PubMed Central

Background High-Density Lipoprotein (HDL), one of the main plasma lipoproteins, serves as a docking station for proteins involved in inflammation, coagulation, and lipid metabolism. Methods To elucidate the protein composition of HDL, we employed SELDI-TOF mass spectrometry as a potential high-throughput proteomic candidate for protein profiling of HDL. HDL derived from normolipemic individuals was captured on PS20 protein-chips using covalently bound antibodies against apo A-I or A-II. Results After optimisation, on-chip capture of HDL particles directly from plasma or from pre-purified HDL resulted in comparable fingerprints confirming specific capture of HDL. Depending on the capture antibody some differences in the fingerprint were observed. The most detailed fingerprint was observed up to 50 kDa; approximately 95 peaks were detected in the 3–50 kDa molecular mass range. Between 50 and 160 kDa, 27 more peaks were detected. Conclusion Based on these results, SELDI-TOF MS may be a suitable high-throughput candidate for HDL protein profiling and marker search. This approach may be used to i) investigate the underlying mechanisms that lead to increased atherothrombotic risk and ii) to investigate the atherothrombotic state of an individual. PMID:17822561

Levels, Johannes HM; Bleijlevens, Boris; Rezaee, Farhad; Aerts, Johannes MFG; Meijers, Joost CM

2007-01-01

299

Accurate mass error correction in liquid chromatography time-of-flight mass spectrometry based metabolomics  

Microsoft Academic Search

Compound identification and annotation in (untargeted) metabolomics experiments based on accurate mass require the highest\\u000a possible accuracy of the mass determination. Experimental LC\\/TOF-MS platforms equipped with a time-to-digital converter (TDC)\\u000a give the best mass estimate for those mass signals with an intensity similar to that of the lock-mass used for internal calibration.\\u000a However, they systematically underestimate the mass obtained at

Velitchka V. Mihaleva; Oscar Vorst; Chris Maliepaard; Harrie A. Verhoeven; Ric C. H. de Vos; Robert D. Hall; Roeland C. H. J. van Ham

2008-01-01

300

Identification of amiodarone metabolites in human bile by ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry.  

PubMed

Amiodarone is recognized as an effective drug in the treatment of arrhythmias. Previous experiments demonstrated that mono-N-desethylamiodarone (MDEA) was the major circulating metabolite in humans. In addition, dealkylation, hydroxylation, and deamination were minor metabolic pathways. The purpose of this study was to identify the metabolites of amiodarone in the bile obtained from patients with T-tube drainage after oral drug administration. Amiodarone metabolism in vitro was also investigated using human liver microsomes (HLMs) and S9 fraction. Ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF MS) revealed 33 metabolites in human bile, including 22 phase I and 11 phase II metabolites. The major metabolites were MDEA (M7) and ?-carboxylate amiodarone (M12). Metabolite M12 was isolated from human bile, and the chemical structure was confirmed using UPLC-Q/TOF MS and ¹H NMR. Moreover, the authentic standards of two hydroxylated metabolites, 2-hydroxylamiodarone and 3'-hydroxylamiodarone, were obtained through microbial transformation. Several novel metabolic pathways of amiodarone in human were proposed, including ?-carboxylation, deiodination, and glucuronidation. The in vitro study demonstrated that incubation of HLMs with amiodarone did not give rise to any carboxyl metabolites. In contrast, M12 and its metabolites were detected in human liver S9 incubation samples, and the production of these metabolites were inhibited almost completely by 4-methylpyrazole, an inhibitor of alcohol dehydrogenase, suggesting the involvement of alcohol dehydrogenase in the ?-carboxylation of amiodarone. Overall, UPLC-Q/TOF MS analysis leads to the discovery of several novel amiodarone metabolites in human bile and underscores the importance of bile as an excretion pathway. PMID:21398391

Deng, Pan; You, Tiangeng; Chen, Xiaoyan; Yuan, Tao; Huang, Haihua; Zhong, Dafang

2011-06-01

301

MALDI-TOF MS imaging of metabolites with a N-(1-naphthyl) ethylenediamine dihydrochloride matrix and its application to colorectal cancer liver metastasis.  

PubMed

Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) is a label-free technique for identifying multiplex metabolites and determining both their distribution and relative abundance in situ. Our previous study showed that N-(1-naphthyl) ethylenediamine dihydrochloride (NEDC) could act as a matrix for laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF MS) detection of oligosaccharides in solution. In the present study, NEDC-assisted LDI-TOF MSI yielded many more endogenous compound peaks between m/z 60 and m/z 1600 than 9-aminoacridine (9-AA). Our results show that NEDC-assisted LDI-TOF MSI is especially well-suited for examining distributions of glycerophospholipids (GPs) in addition to low molecular weight metabolites below m/z 400. Particularly, NEDC matrix allowed the LDI-TOF MSI of glucose in animal tissue. Furthermore, NEDC-assisted LDI-TOF MSI was applied to a mouse model of colorectal cancer liver metastasis. We revealed the distinct spatio-molecular signatures of many detected compounds in tumor or tumor-bearing liver, and we found that taurine, glucose, and some GPs decreased in tumor-bearing liver as the tumor developed in liver. Importantly, we also found a glucose gradient in metastatic tumor foci for the first time, which further confirms the energy competition between tumors and liver remnant due to the Warburg effect. Our results suggest that NEDC-assisted LDI MSI provides an in situ label-free analysis of multiple glycerophospholipids and low molecular weight metabolites (including glucose) with abundant peaks and high spatial resolution. This will allow future application to in situ definition of biomarkers, signaling pathways, and disease mechanisms. PMID:25474421

Wang, Jianing; Qiu, Shulan; Chen, Suming; Xiong, Caiqiao; Liu, Huihui; Wang, Jiyun; Zhang, Ning; Hou, Jian; He, Qing; Nie, Zongxiu

2015-01-01

302

Direct Surface Analysis of Fungal Species by Matrix-assisted Laser Desorption/Ionization Mass Spectrometry  

SciTech Connect

Intact spores and/or hyphae of Aspergillus niger, Rhizopus oryzae, Trichoderma reesei and Phanerochaete chrysosporium are analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). This study investigates various methods of sample preparation and matrices to determine optimum collection and analysis criteria for fungal analysis by MALDI-MS. Fungi are applied to the MALDI sample target as untreated, sonicated, acid/heat treated, or blotted directly from the fungal culture with double-stick tape. Ferulic acid or sinapinic acid matrix solution is layered over the dried samples and analyzed by MALDI-MS. Statistical analysis of the data show that simply using double stick tape to collect and transfer to a MALDI sample plate typically worked as well as the other preparation methods, but requires the least sample handling.

Valentine, Nancy B. (BATTELLE (PACIFIC NW LAB)); Wahl, Jon H. (BATTELLE (PACIFIC NW LAB)); Kingsley, Mark T. (BATTELLE (PACIFIC NW LAB)); Wahl, Karen L. (BATTELLE (PACIFIC NW LAB))

2001-12-01

303

VMSL: Virtual Mass Spectrometry Laboratory  

NSDL National Science Digital Library

This site presents a series of case studies that can be explored using modern mass spectrometry methods. The problem-solving nature of the site provides students a virtual laboratory experience that can supplement access to mass spectrometry instrumentation.

2011-07-05

304

Mass Spectrometry and Glycomics  

PubMed Central

Abstract Glycosylation defines the adhesive properties of animal cell surfaces and the surrounding extracellular environments. Because cells respond to stimuli by altering glycan expression, glycan structures vary according to spatial location in tissue and temporal factors. These dynamic structural expression patterns, combined with the essential roles glycans play in physiology, drive the need for analytical methods for glycoconjugates. In addition, recombinant glycoprotein drug products represent a multibillion dollar market. Effective analytical methods are needed to speed the identification of new targets and the development of industrial glycoprotein products, both new and biosimilar. Mass spectrometry is an enabling technology in glycomics. This review summarizes mass spectrometry of glycoconjugate glycans. The intent is to summarize appropriate methods for glycans given their chemical properties as distinct from those of proteins, lipids, and small molecule metabolites. Special attention is given to the uses of mass spectral profiling for glycomics with respect to the N-linked, O-linked, ganglioside, and glycosaminoglycan compound classes. Next, the uses of tandem mass spectrometry of glycans are summarized. The review finishes with an update on mass spectral glycoproteomics. PMID:20443730

2010-01-01

305

The Interaction Between Endopolygalacturonase From Fusarium Moniliforme and PGIP from Phaseolus Vulgaris Studied by Surface Plasmon Resonance and Mass Spectrometry  

PubMed Central

A combination of surface plasmon resonance (SPR) and matrix-assisted laser-desorptionionization- time-of-flight mass spectrometry (MALDI-TOF-MS) was used to study the interaction between endopolygalacturonase (PG) from Fusarium moniliforme and a polygalacturonase-inhibiting protein (PGIP) from Phaseolus vulgaris. PG hydrolyses the homogalacturonan of the plant cell wall and is considered an important pathogenicity factor of many fungi. PGIP is a specific inhibitor of fungal PGs and is thought to be involved in plant defence against phytopathogenic fungi. SPR was used either to study the effect of the PG glycosylation on the formation of the complex with PGIP, and as a sensitive affinity capture of an interacting peptide from a mixture of PG fragments obtained by limited proteolysis. Mass spectrometry allowed to characterise the interacting peptide eluted from the sensor surface. PMID:18628868

Cervone, Felice; Roepstorff, Peter

2001-01-01

306

Detection of Pancreatic Cancer Biomarkers Using Mass Spectrometry  

PubMed Central

BACKGROUND Pancreatic cancer is the fourth leading cause of cancer-related deaths. Therefore, in order to improve survival rates, the development of biomarkers for early diagnosis is crucial. Recently, diabetes has been associated with an increased risk of pancreatic cancer. The aims of this study were to search for novel serum biomarkers that could be used for early diagnosis of pancreatic cancer and to identify whether diabetes was a risk factor for this disease. METHODS Blood samples were collected from 25 patients with diabetes (control) and 93 patients with pancreatic cancer (including 53 patients with diabetes), and analyzed using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF/MS). We performed preprocessing, and various classification methods with imputation were used to replace the missing values. To validate the selection of biomarkers identified in pancreatic cancer patients, we measured biomarker intensity in pancreatic cancer patients with diabetes following surgical resection and compared our results with those from control (diabetes-only) patients. RESULTS By using various classification methods, we identified the commonly splitting protein peaks as m/z 1,465, 1,206, and 1,020. In the follow-up study, in which we assessed biomarkers in pancreatic cancer patients with diabetes after surgical resection, we found that the intensities of m/z at 1,465, 1,206, and 1,020 became comparable with those of diabetes-only patients. PMID:25673969

Kim, Kiyoun; Ahn, Soohyun; Lim, Johan; Yoo, Byong Chul; Hwang, Jin-Hyeok; Jang, Woncheol

2014-01-01

307

On-line Measurement of Biogenic Volatile Organic Compounds (BVOCs) and Their Oxidation Products by PTR-TOF-MS in a Forest Environment in the Southeastern U.S  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compounds (BVOCs) including isoprene, monoterpenes, sesquiterpenes and some oxygenated species emitted from vegetation comprise the largest fraction (about 90%) of global non-methane VOC emissions. The Southeastern U.S. experiences very high emissions of biogenic VOCs during the summertime because of high temperatures and heavy local forestation. To further understand the role of biogenic VOCs in shaping local and regional photochemistry, a Proton Transfer Reaction time-of-flight Mass Spectrometry (PTR-TOF-MS) was deployed at a forest site in eastern Tennessee from June 10th to July 16th, 2013 to measure mixing ratios of BVOCs and their oxidation products, as part of the Southern Oxidant and Aerosol Study (SOAS). Isoprene was observed to be the dominant BVOC species at the site, typically reaching a maximum mixing ratio of about 6 ppbv in the early afternoon. Mixing ratios of other biogenic VOCs such as monoterpenes were relatively low (<1ppb). Most of the time, methyl vinyl ketone and methacrolein (MVK+MACR), the major products from OH-initiated isoprene oxidation, tracked well with their precursor. Their mixing ratios typically increased in late morning and maintained relatively high levels in the afternoon and evening before decreasing gradually overnight. The possibility of distinguishing MVK and MACR using NO+ as a reagent ion in the PTR-TOF-MS was also explored. Combined with recent results from laboratory chamber experiments, the ratios between isoprene and its oxidation products are used to understand the oxidation pathways of isoprene in this biogenically-dominated area. Oxygenated VOCs (OVOCs), including formaldehyde and acetone, were also observed at the site. Multi-variate regression analysis of VOC time series is applied to identify contributions from biogenic and anthropogenic emissions and other possible sources, and to understand relationships between primary and secondary compounds in the atmosphere.

Liu, Y.; McKinney, K. A.

2013-12-01

308

Evaluation of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry in comparison to 16S rRNA gene sequencing for species identification of nonfermenting bacteria.  

PubMed

Nonfermenting bacteria are ubiquitous environmental opportunists that cause infections in humans, especially compromised patients. Due to their limited biochemical reactivity and different morphotypes, misidentification by classical phenotypic means occurs frequently. Therefore, we evaluated the use of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) for species identification. By using 248 nonfermenting culture collection strains composed of 37 genera most relevant to human infections, a reference database was established for MALDI-TOF MS-based species identification according to the manufacturer's recommendations for microflex measurement and MALDI BioTyper software (Bruker Daltonik GmbH, Leipzig, Germany), i.e., by using a mass range of 2,000 to 20,000 Da and a new pattern-matching algorithm. To evaluate the database, 80 blind-coded clinical nonfermenting bacterial strains were analyzed. As a reference method for species designation, partial 16S rRNA gene sequencing was applied. By 16S rRNA gene sequencing, 57 of the 80 isolates produced a unique species identification (>or=99% sequence similarity); 11 further isolates gave ambiguous results at this threshold and were rated as identified to the genus level only. Ten isolates were identified to the genus level (>or=97% similarity); and two isolates had similarity values below this threshold, were counted as not identified, and were excluded from further analysis. MALDI-TOF MS identified 67 of the 78 isolates (85.9%) included, in agreement with the results of the reference method; 9 were misidentified and 2 were unidentified. The identities of 10 randomly selected strains were 100% correct when three different mass spectrometers and four different cultivation media were used. Thus, MALDI-TOF MS-based species identification of nonfermenting bacteria provided accurate and reproducible results within 10 min without any substantial costs for consumables. PMID:18400920

Mellmann, A; Cloud, J; Maier, T; Keckevoet, U; Ramminger, I; Iwen, P; Dunn, J; Hall, G; Wilson, D; Lasala, P; Kostrzewa, M; Harmsen, D

2008-06-01

309

Evaluation of Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry in Comparison to 16S rRNA Gene Sequencing for Species Identification of Nonfermenting Bacteria?  

PubMed Central

Nonfermenting bacteria are ubiquitous environmental opportunists that cause infections in humans, especially compromised patients. Due to their limited biochemical reactivity and different morphotypes, misidentification by classical phenotypic means occurs frequently. Therefore, we evaluated the use of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) for species identification. By using 248 nonfermenting culture collection strains composed of 37 genera most relevant to human infections, a reference database was established for MALDI-TOF MS-based species identification according to the manufacturer's recommendations for microflex measurement and MALDI BioTyper software (Bruker Daltonik GmbH, Leipzig, Germany), i.e., by using a mass range of 2,000 to 20,000 Da and a new pattern-matching algorithm. To evaluate the database, 80 blind-coded clinical nonfermenting bacterial strains were analyzed. As a reference method for species designation, partial 16S rRNA gene sequencing was applied. By 16S rRNA gene sequencing, 57 of the 80 isolates produced a unique species identification (?99% sequence similarity); 11 further isolates gave ambiguous results at this threshold and were rated as identified to the genus level only. Ten isolates were identified to the genus level (?97% similarity); and two isolates had similarity values below this threshold, were counted as not identified, and were excluded from further analysis. MALDI-TOF MS identified 67 of the 78 isolates (85.9%) included, in agreement with the results of the reference method; 9 were misidentified and 2 were unidentified. The identities of 10 randomly selected strains were 100% correct when three different mass spectrometers and four different cultivation media were used. Thus, MALDI-TOF MS-based species identification of nonfermenting bacteria provided accurate and reproducible results within 10 min without any substantial costs for consumables. PMID:18400920

Mellmann, A.; Cloud, J.; Maier, T.; Keckevoet, U.; Ramminger, I.; Iwen, P.; Dunn, J.; Hall, G.; Wilson, D.; LaSala, P.; Kostrzewa, M.; Harmsen, D.

2008-01-01

310

Structural characterization and identification of iridoid glycosides, saponins, phenolic acids and flavonoids in Flos Lonicerae Japonicae by a fast liquid chromatography method with diode-array detection and time-of-flight mass spectrometry.  

PubMed

A fast liquid chromatography method with diode-array detection (DAD) and time-of-flight mass spectrometry (TOF-MS) has been developed for analysis of constituents in Flos Lonicerae Japonicae (FLJ), a traditional Chinese medicine derived from the flower bud of Lonicera japonica. The chromatographic analytical time decreased to 25 min without sacrificing resolution using a column packed with 1.8-microm porous particles (4.6 x 50 mm), three times faster than the performance of conventional 5.0-microm columns (4.6 x 150 mm). Four major groups of compounds previously isolated from FLJ were structurally characterized by DAD-TOF-MS: iridoid glycosides showed maximum UV absorption at 240 nm; phenolic acids at 217, 242, and 326 nm; flavonoids at 255 and 355 nm; while saponins had no absorption. In electrospray ionization (ESI)-TOF-MS experiments, elimination of a glucose unit (162 Da), and successive losses of H(2)O, CH(3)OH and CO, were generally observed in iridoid glycosides; saponins were characterized by a series of identical aglycone ions; phenolic acids typically generated a base peak at [M-H-caffeoyl](-) by loss of a caffeic acid unit (162 Da) and several marked quinic acid moiety ions; cleavage of the glycosidic bond (loss of 162 or 308 Da), subsequent losses of H(2)O, CO, RDA and C-ring fragmentation were the most possible fragmentation pathways for flavonoids. By accurate mass measurements within 4 ppm error for each molecular ion and subsequent fragment ions, as well as the 'full mass spectral' information of TOF-MS, a total of 41 compounds including 13 iridoid glycosides, 11 phenolic acids, 7 saponins, and 10 flavonoids were identified in a methanolic extract of FLJ. PMID:19725056

Qi, Lian-Wen; Chen, Chun-Yun; Li, Ping

2009-10-01

311

Mass Spectrometry and Protein Analysis  

Microsoft Academic Search

Mass spectrometry is a central analytical technique for protein research and for the study of biomolecules in general. Driven by the need to identify, characterize, and quantify proteins at ever increasing sensitivity and in ever more complex samples, a wide range of new mass spectrometry-based analytical platforms and experimental strategies have emerged. Here we review recent advances in mass spectrometry

Bruno Domon; Ruedi Aebersold

2006-01-01

312

A SIMPLE AND RAPID MATRIX-ASSISTED LASER DESORPTION/IONIZATION TIME OF FLIGHT MASS SPECTRONOMY METHOD TO SCREEN FISH PLASMA SAMPLES FOR ESTROGEN-RESPONSIVE BIOMARKERS  

EPA Science Inventory

In this study, we describe and evaluate the performance of a simple and rapid mass spectral method for screening fish plasma for estrogen-responsive biomarkers using matrix assisted laster desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) couopled with a short...

313

Rapid MALDI-TOF MS analysis of bacteriophage major capsid proteins with -mercaptoethanol sample pretreatment  

E-print Network

Rapid MALDI-TOF MS analysis of bacteriophage major capsid proteins with -mercaptoethanol sample Technology Laboratory; Colorado School of Mines, Golden CO 80401 Introduction: ·Bacteriophage (phage bacteriophage -A1122 (which is utilized for plague detection) were analyzed by combining 100µL of phage solution

314

Analysis of drugs of forensic interest with capillary zone electrophoresis/time-of-flight mass spectrometry based on the use of non-volatile buffers.  

PubMed

The present work is aimed at investigating the influence of the background electrolyte composition and concentration on the separation efficiency and resolution and mass spectrometric detection of illicit drugs in a capillary zone electrophoresis-electrospray ionization-time of flight mass spectrometry (CZE-ESI-TOF MS) system. The effect of phosphate, borate and Tris buffers on the separation and mass spectrometry response of a mixture of 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, methadone, cocaine, morphine, codeine and 6-monoacetylmorphine was studied, in comparison with a reference ammonium formate separation buffer. Inorganic non-volatile borate and Tris buffers proved hardly suitable for capillary electrophoresis-mass spectrometry (CE-MS) analysis, but quite unexpectedly ammonium phosphate buffers showed good separation and ionization performances for all the analytes tested. Applications of this method to real samples of hair from drug addicts are also provided. PMID:22451052

Gottardo, Rossella; Mikšík, Ivan; Aturki, Zeineb; Sorio, Daniela; Seri, Catia; Fanali, Salvatore; Tagliaro, Franco

2012-02-01

315

Comparison of matrix-assisted laser desorption ionization-time of flight mass spectrometry and molecular biology techniques for identification of culicoides (Diptera: ceratopogonidae) biting midges in senegal.  

PubMed

Biting midges of the genus Culicoides are implicated as vectors for a wide variety of pathogens. The morphological identification of these arthropods may be difficult because of a lack of detailed investigation of taxonomy for this species in Africa. However, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) profiling is efficient for arthropod identification at the species level. This study established a spectrum database of Culicoides spp. from Senegal using MALDI-TOF. Identification of Culicoides insects to the species level before mass spectrometry was performed on the basis of morphological characters. MALDI-TOF MS reference spectra were determined for 437 field-caught Culicoides of 10 species. The protein profiles of all tested Culicoides revealed several peaks with mass ranges of 2 to 20 kDa. In a validation study, 72 Culicoides specimens in the target species were correctly identified at the species level with a similarity of 95 to 99.9%. Four Culicoides protein profiles were misidentified. Nevertheless, six SuperSpectra (C. imicola, C. enderleini, C. oxystoma, C. kingi, C. magnus, and C. fulvithorax) were created. Abdomens of midges were used to amplify and sequence a portion of the mitochondrial cytochrome oxidase I gene (COI). The results obtained using the MALDI-TOF MS method were consistent with the morphological identification and similar to the genetic identification. Protein profiling using MALDI-TOF is an efficient approach for the identification of Culicoides spp., and it is economically advantageous for approaches that require detailed and quantitative information of vector species that are collected in field. The database of African Culicoides MS spectra created is the first database in Africa. The COI sequences of five Culicoides species that were previously noncharacterized using molecular methods were deposited in GenBank. PMID:25411169

Sambou, Masse; Aubadie-Ladrix, Maxence; Fenollar, Florence; Fall, Becaye; Bassene, Hubert; Almeras, Lionel; Sambe-Ba, Bissoume; Perrot, Nadine; Chatellier, Sonia; Faye, Ngor; Parola, Philippe; Wade, Boubacar; Raoult, Didier; Mediannikov, Oleg

2015-02-01

316

Detection of a chemical warfare agent simulant in various aerosol matrixes by ion mobility time-of-flight mass spectrometry.  

PubMed

For the first time, a traditional radioactive nickel (63Ni) beta emission ionization source for ion mobility spectrometry was employed with an atmospheric pressure ion mobility orthogonal reflector time-of-flight mass spectrometer (IM(tof)MS) to detect a chemical warfare agent (CWA) simulant from aerosol samples. Aerosol-phase sampling employed a quartz cyclonic chamber for sample introduction. The simulant reference material, which closely mimicked the characteristic chemical structure of CWAs as defined and described by Schedule 1, 2, or 3 of the Chemical Warfare Convention treaty verification, was used in this study. An overall elevation in arbitrary signal intensity of approximately 1.0 orders of magnitude was obtained by the progressive increase of the thermal AP-IMS temperature from 75 to 275 degrees C. A mixture of one G-type nerve simulant (dimethyl methylphosphonate (DMMP)) in four (water, kerosene, gasoline, diesel) matrixes was found in each case (AP-IMS temperature 75-275 degrees C) to be clearly resolved in less than 2.20 x 10(4) micros using the IM(tof)MS instrument. Corresponding ions, masses, drift times, K(o) values, and arbitrary signal intensities for each of the sample matrixes are reported for the CWA simulant DMMP. PMID:16053290

Steiner, Wes E; Klopsch, Steve J; English, William A; Clowers, Brian H; Hill, Herbert H

2005-08-01

317

Qualitative and quantitative analysis of Andrographis paniculata by rapid resolution liquid chromatography/time-of-flight mass spectrometry.  

PubMed

A rapid resolution liquid chromatography/time-of-flight tandem mass spectrometry (RRLC-TOF/MS) method was developed for qualitative and quantitative analysis of the major chemical constituents in Andrographis paniculata. Fifteen compounds, including flavonoids and diterpenoid lactones, were unambiguously or tentatively identified in 10 min by comparing their retention times and accurate masses with standards or literature data. The characteristic fragmentation patterns of flavonoids and diterpenoid lactones were summarized, and the structures of the unknown compounds were predicted. Andrographolide, dehydroandrographolide and neoandrographolide were further quantified as marker substances. It was found that the calibration curves for all analytes showed good linearity (R² > 0.9995) within the test ranges. The overall limits of detection (LODs) and limits of quantification (LOQs) were 0.02 ?g/mL to 0.06 ?g/mL and 0.06 ?g/mL to 0.2 ?g/mL, respectively. The relative standard deviations (RSDs) for intra- and inter-day precisions were below 3.3% and 4.2%, respectively. The mean recovery rates ranged from 96.7% to 104.5% with the relative standard deviations (RSDs) less than 2.72%. It is concluded that RRLC-TOF/MS is powerful and practical in qualitative and quantitative analysis of complex plant samples due to time savings, sensitivity, precision, accuracy and lowering solvent consumption. PMID:24084022

Song, Yong-Xi; Liu, Shi-Ping; Jin, Zhao; Qin, Jian-Fei; Jiang, Zhi-Yuan

2013-01-01

318

Mass Spectrometric Analysis of Lipopeptide from Bacillus Strains Isolated from Diverse Geographical Locations  

Technology Transfer Automated Retrieval System (TEKTRAN)

Matrix-assisted laser desorption/ionization time-of flight mass spectrometry (MALDI-TOF MS) has been applied to characterize lipopeptide biomarkers from 54 different strains of Bacillis from most taxa within the B. subtilis - B. licheniformis clade, isolated from 7 different geographic locations on ...

319

Systematic HPLC/ESI-High Resolution-qTOF-MS Methodology for Metabolomic Studies in Nonfluorescent Chlorophyll Catabolites Pathway  

PubMed Central

Characterization of nonfluorescent chlorophyll catabolites (NCCs) and dioxobilane-type nonfluorescent chlorophyll catabolite (DNCC) in peel extracts of ripened lemon fruits (Citrus limon L.) was performed by HPLC/ESI-high resolution-qTOF-MS method. Compounds were identified in samples on the basis of measured accurate mass, isotopic pattern, and characteristic fragmentation profile with an implemented software postprocessing routine. Three NCC structures already identified in other vegetal tissues were present in the lemon fruit peels (Cl-NCC1; Cl-NCC2; Cl-NCC4) while a new structure not defined so far was characterized (Cl-NCC3). This catabolite exhibits an exceptional arrangement of the peripheral substituents, allowing concluding that the preferences for the NCC modifications could be a species-related matter. PMID:25741450

Ríos, José Julián; Roca, María; Pérez-Gálvez, Antonio

2015-01-01

320

Mass Spectrometry Video  

NSDL National Science Digital Library

This video, distributed on YouTube by the Royal Society of Chemistry is on the basic principles of mass spectrometry, using a magnetic sector instrument to demonstrate how specific m/z ratios can be selected. The theory and operation of MS, including the chemistry of ionization and fragmentation is described at an introductory level. There is also an excellent example of the use of high resolution MS to differentiate between nominal mass and actual mass. The video does a very good job of explaining the concept such that only a little background knowledge is required. The video is short enough (6 mins), that it would be very useful in a class setting or for students outside of class. The ultimate strength of this video is the general nature of the content that makes it appealing to a wide audience. The video may be most appropriate in a lower-level general education science course (i.e forensic science) or as a quick orientation video for instrumental analysis students prior to introducing mathematical or operational concepts. This video would also be helpful for a lay science person who wishes to learn more about mass spectrometry from a general interest perspective.

321

Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry applied to virus identification  

PubMed Central

Virus detection and/or identification traditionally rely on methods based on cell culture, electron microscopy and antigen or nucleic acid detection. These techniques are good, but often expensive and/or time-consuming; furthermore, they not always lead to virus identification at the species and/or type level. In this study, Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) was tested as an innovative tool to identify human polioviruses and to identify specific viral protein biomarkers in infected cells. The results revealed MALDI-TOF MS to be an effective and inexpensive tool for the identification of the three poliovirus serotypes. The method was firstly applied to Sabin reference strains, and then to isolates from different clinical samples, highlighting its value as a time-saving, sensitive and specific technique when compared to the gold standard neutralization assay and casting new light on its possible application to virus detection and/or identification. PMID:25354905

Calderaro, Adriana; Arcangeletti, Maria-Cristina; Rodighiero, Isabella; Buttrini, Mirko; Gorrini, Chiara; Motta, Federica; Germini, Diego; Medici, Maria-Cristina; Chezzi, Carlo; De Conto, Flora

2014-01-01

322

Histone H4 acetylation dynamics determined by stable isotope labeling with amino acids in cell culture and mass spectrometry.  

PubMed

This paper describes an integrated approach that couples stable isotope labeling with amino acids in cell culture to acetic acid-urea polyacrylamide gel electrophoresis (AU-PAGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the quantitation and dynamics of histone H4 acetylation. The 697 acute lymphoblastic cell lines were grown in regular medium and in medium in which lysine was substituted with deuterium-labeled lysine. Histone deacetylase (HDAC) activity was inhibited by addition of the HDAC inhibitor depsipeptide to the culture medium for different exposure times. Histones were extracted from cells pooled from unlabeled, untreated cells and from labeled, treated cells, followed by AU-PAGE separation. Gel bands corresponding to different acetylation states of H4 were excised, in-gel digested with trypsin, and analyzed by MALDI-TOF MS. Detailed information was obtained for both the change of histone H4 acetylation specific to the N terminus and the global transformation of H4 from one acetylation state to another following treatment with the HDAC inhibitor depsipeptide. The kinetics of H4 acetylation was also assessed. This study provides a quantitative basis for developing potential therapies by using epigenetic regulation and the developed methodology can be applied to quantitation of change for other histone modifications induced by external stimuli. PMID:17286952

Su, Xiaodan; Zhang, Liwen; Lucas, David M; Davis, Melanie E; Knapp, Amy R; Green-Church, Kari B; Marcucci, Guido; Parthun, Mark R; Byrd, John C; Freitas, Michael A

2007-04-01

323

Identification of phlebotomine sand flies (Diptera: Psychodidae) by matrix-assisted laser desorption/ionization time of flight mass spectrometry  

PubMed Central

Background Phlebotomine sand flies are incriminated in the transmission of several human and veterinary pathogens. To elucidate their role as vectors, proper species identification is crucial. Since traditional morphological determination is based on minute and often dubious characteristics on their head and genitalia, which require certain expertise and may be damaged in the field-collected material, there is a demand for rapid, simple and cost-effective molecular approaches. Methods Six laboratory-reared colonies of phlebotomine sand flies belonging to five species and four subgenera (Phlebotomus, Paraphlebotomus, Larroussius, Adlerius) were used to evaluate the discriminatory power of matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Various storage conditions and treatments, including the homogenization in either distilled water or given concentrations of formic acid, were tested on samples of both sexes. Results Specimens of all five analysed sand fly species produced informative, reproducible and species-specific protein spectra that enabled their conclusive species identification. The method also distinguished between two P. sergenti colonies originating from different geographical localities. Protein profiles within a species were similar for specimens of both sexes. Tested conditions of specimen storage and sample preparation give ground to a standard protocol that is generally applicable on analyzed sand fly specimens. Conclusions Species identification of sand flies by MALDI-TOF MS is feasible and represents a novel promising tool to improve biological and epidemiological studies on these medically important insects. PMID:24423215

2014-01-01

324

Application of gas chromatography-mass spectrometry metabolite profiling techniques to the analysis of heathland plant diets of sheep.  

PubMed

Little is known about how plant biochemistry influences the grazing behavior of animals consuming heterogeneous plant communities. The biochemical profiles of grassland species are mostly restricted to major nutritional characteristics, although recent developments in analytical techniques and data analysis have made possible the detailed analysis of minor components that may influence animal feeding preferences, performance, and health. In the present study, gas chromatography coupled with time-of-flight mass spectrometry (GC-TOF/MS) was used to profile the abundances of metabolites in nine specific heathland plant groups and in three mixed forage diets containing 10, 20, or 30% heather (Calluna vulgaris) and also in plasma and feces from sheep offered one of the three diets. Statistical and chemometric approaches, that is, principal component analysis (PCA) and hierarchical cluster analysis (HCA), were used to discriminate between these diets and between individual animals maintained on these diets. It is shown that GC-TOF/MS analysis of sheep plasma allowed distinction between the very similar diets by PCA and HCA, and, moreover, the plant metabolites responsible for the differences observed have been identified. Furthermore, metabolite markers of herbage mixtures and individual plant groups have been identified, and markers have been detected in sheep plasma and feces. PMID:17249687

Parveen, Ifat; Moorby, Jon M; Fraser, Mariecia D; Allison, Gordon G; Kopka, Joachim

2007-02-21

325

Real-Time Analysis of Water by Membrane Introduction/Laser Ionization Time-of-Flight Mass Spectrometry  

NASA Astrophysics Data System (ADS)

Two photon resonance enhanced multiphoton ionization (REMPI) has been shown to be an unique ionization method for mass spectrometry with high sensitivity and selectivity. This method has been used for about thirty years for fundamental studies in molecular spectroscopy and dynamics, but recently has been examined and developed as a tool for fast, rapid on-line monitoring of complex gas mixtures. The list of reported successful applications includes on-line monitoring of combustion processes, monitoring of automotive exhaust and the formation chemistry of Polychlorinated Dioxins/Furans in waste incineration. At SRI International we are studying the REMPI method for analytical purposes for the determination of trace amounts of hazardous air pollutants, toxics in vehicle exhausts, breath analysis, cancer drugs, and explosives. Since REMPI is a gas phase method, REMPI applications have been limited and applied to gas phase systems or in conjunction with a combination of laser desorption and subsequent laser ionization. We describe here for the first time a combination of MIMS and REMPI with time-of flight mass spectrometry (ToF MS), which allows the direct analysis of water samples. The application of ToF MS offers some advantages like high transmission, robustness, and the ability to record a mass spectrum per each laser shot The objective of this research was the detection of trace amounts of aromatic contaminants particularly BETX in aqueous solutions without interference or clogging of the inlet due to the vastly greater amount of water. To our knowledge, this combination of membrane introduction, laser photoionization and ToF MS has not been examined previously. A significant feature of MIMS is the simultaneous introduction of all analytes into the mass spectrometer. This results in a rapid analytical method, suitable for on-line applications. However, the application of conventional ionization methods presumably electron impact, making the analysis of complex mixtures more difficult. In most MIMS applications, the mass spectrometer has been a standard quadrupole instrument; ion traps and time-of-flight (TOF) devices have also been used. Almost all these studies utilized electron impact ionization. The laser photoionization method, which generally can be adjusted not to photofragment the compounds, allows identification from the parent ion masses only. It offers the advantages both of sensitive, rapid analysis without prior separation or preparation process, and of parent ion mass identification without deconvolution of multiple mass peaks.

Oser, H.; Irwin, A.; Mullen, C.; Coggiola, M. J.

2005-12-01

326

Mass Spectrometry and Biotechnology Resource  

NSDL National Science Digital Library

Ionsource is a website that provides access to an index of resources including tutorials, links to downloadable sites, jobs and conference information involving mass spectrometry and biotechnology subjects. Examples of tutorials include lessons on atomic mass and amino acid residue mass. For a review of mass spectrometry or biotechnology or for an introduction, this site provides a well-rounded source of information.

327

Dynamically Multiplexed Ion Mobility Time-of-Flight Mass Spectrometry  

SciTech Connect

Ion Mobility Spectrometry–Time-of-Flight Mass Spectrometry (IMS-TOFMS) has been increasingly used in analysis of complex biological samples. A major challenge is to transform IMS-TOFMS to a high-sensitivity high-throughput platform for e.g. proteomics applications. In this work, we have developed and integrated three advanced technologies, enabling (1) efficient ion accumulation in the ion funnel trap prior to IMS separation, (2) multiplexing (MP) of ion packet introduction into the IMS drift tube and (3) signal detection with an analog-to-digital converter (ADC), into the IMS-TOFMS system for the high-throughput analysis of highly complex proteolytic digests of e.g. blood plasma. To better address variable sample complexity, we have additionally developed and rigorously evaluated a new dynamic MP approach that ensures correlation of the analyzer performance with an ion source function, and provides the improved dynamic range and sensitivity. The MP IMS-TOF MS instrument has been shown to reliably detect peptides at a concentration of 1 nM in a highly complex matrix, as well as to provide a four orders of magnitude dynamic range and a mass measurement accuracy of better than 5 ppm. When matched against human blood plasma database, the detected IMS-TOF features yielded ~ 700 unique peptide identifications at a false discovery rate (FDR) of ~ 7.5 %. Accounting for IMS information gave rise to a projected FDR of ~ 4 %. Signal reproducibility was found to be greater than 80 %, while the variations in the number of unique peptide identifications were < 15 %. A single sample analysis was completed in 15 min, corresponding to approximately an order of magnitude improvement compared to a more conventional LC-MS approach.

Belov, Mikhail E.; Clowers, Brian H.; Prior, David C.; Danielson, William F.; Liyu, Andrei V.; Petritis, Brianne O.; Smith, Richard D.

2008-08-01

328

Comparative proteomics using 2-D gel electrophoresis and mass spectrometry as tools to dissect stimulons and regulons in bacteria with sequenced or partially sequenced genomes  

PubMed Central

We propose two-dimensional gel electrophoresis (2-DE) and mass spectrometry to define the protein components of regulons and stimulons in bacteria, including those organisms where genome sequencing is still in progress. The basic 2-DE protocol allows high resolution and reproducibility and enables the direct comparison of hundreds or even thousands of proteins simultaneously. To identify proteins that comprise stimulons and regulons, peptide mass fingerprint (PMF) with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF-MS) analysis is the first option and, if results from this tool are insufficient, complementary data obtained with electrospray ionization tandem-MS (ESI-MS/MS) may permit successful protein identification. ESI-MS/MS and MALDI-TOF-MS provide complementary data sets, and so a more comprehensive coverage of a proteome can be obtained using both techniques with the same sample, especially when few sequenced proteins of a particular organism exist or genome sequencing is still in progress. PMID:16145578

Hernández, Magdalena; Martínez-Batallar, Gabriel; Contreras, Sandra; del Carmen Vargas, María; Mora, Jaime

2005-01-01

329

Isotope Ratio Mass Spectrometry.  

PubMed

Isotope Ratio Mass Spectrometry (IRMS) is a specialized technique used to provide information about the geographic, chemical, and biological origins of substances. The ability to determine the source of an organic substance stems from the relative isotopic abundances of the elements which comprise the material. Because the isotope ratios of elements such as carbon, hydrogen, oxygen, sulfur, and nitrogen can become locally enriched or depleted through a variety of kinetic and thermodynamic factors, measurement of the isotope ratios can be used to differentiate between samples which otherwise share identical chemical compositions. Several sample introduction methods are now available for commercial isotope ratio mass spectrometers. Combustion is most commonly used for bulk isotopic analysis, whereas gas and liquid chromatography are predominately used for the real-time isotopic analysis of specific compounds within a mixture. Here, highlights of advances in instrumentation and applications within the last three years are provided to illustrate the impact of this rapidly growing area of research. Some prominent new applications include authenticating organic food produce, ascertaining whether or not African elephants are guilty of night-time raids on farmers' crops, and linking forensic drug and soil samples from a crime scene to a suspected point of origin. For the sake of brevity, we focus this Minireview on the isotope ratio measurements of lighter-elements common to organic sources; we do not cover the equally important field of inorganic isotope ratio mass spectrometry. PMID:19173039

Muccio, Zeland; Jackson, Glen P

2009-02-01

330

Mass Spectrometry of Glycans  

PubMed Central

Powerful new strategies based on mass spectrometry are revolutionizing the structural analysis and profiling of glycans and glycoconjugates. We survey here the major biosynthetic pathways that underlie the biological diversity in glycobiology, with emphasis on glycoproteins, and the approaches that can be used to address the resulting heterogeneity. Included among these are derivatizations, on- and off-line chromatography, electrospray and matrix-assisted laser desorption/ionization, and a variety of dissociation methods, the recently introduced electron-based techniques being of particular interest. PMID:24010834

Han, Liang; Costello, Catherine E.

2014-01-01

331

MALDI-based intact spore mass spectrometry of downy and powdery mildews.  

PubMed

Fast and easy identification of fungal phytopathogens is of great importance in agriculture. In this context, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has emerged as a powerful tool for analyzing microorganisms. This study deals with a methodology for MALDI-TOF MS-based identification of downy and powdery mildews representing obligate biotrophic parasites of crop plants. Experimental approaches for the MS analyses were optimized using Bremia lactucae, cause of lettuce downy mildew, and Oidium neolycopersici, cause of tomato powdery mildew. This involved determining a suitable concentration of spores in the sample, selection of a proper MALDI matrix, looking for the optimal solvent composition, and evaluation of different sample preparation methods. Furthermore, using different MALDI target materials and surfaces (stainless steel vs polymer-based) and applying various conditions for sample exposure to the acidic MALDI matrix system were investigated. The dried droplet method involving solvent evaporation at room temperature was found to be the most suitable for the deposition of spores and MALDI matrix on the target and the subsequent crystallization. The concentration of spore suspension was optimal between 2 and 5?×?10(9) spores per ml. The best peptide/protein profiles (in terms of signal-to-noise ratio and number of peaks) were obtained by combining ferulic and sinapinic acids as a mixed MALDI matrix. A pretreatment of the spore cell wall with hydrolases was successfully introduced prior to MS measurements to obtain more pronounced signals. Finally, a novel procedure was developed for direct mass spectra acquisition from infected plant leaves. PMID:22899506

Chalupová, Jana; Sedlá?ová, Michaela; Helmel, Michaela; Rehulka, Pavel; Marchetti-Deschmann, Martina; Allmaier, Günter; Sebela, Marek

2012-08-01

332

Flow injection mass spectral fingerprints demonstrate chemical differences in rio red grapefruit with respect to year, harvest time, and conventional versus organic farming  

Technology Transfer Automated Retrieval System (TEKTRAN)

Spectral fingerprints were acquired for Ruby Red grapefruit using direct injection-electrospray ionization with time-of-flight and ion trap mass spectrometry (DI-ESI-TOF-MS and DI-ESI-IT-MS). Rio Red grapefruits were harvested 3 times a year (early, mid, and late harvests) in 2005 and 2006 from con...

333

Single event mass spectrometry  

DOEpatents

A means and method for single event time of flight mass spectrometry for analysis of specimen materials. The method of the invention includes pulsing an ion source imposing at least one pulsed ion onto the specimen to produce a corresponding emission of at least one electrically charged particle. The emitted particle is then dissociated into a charged ion component and an uncharged neutral component. The ion and neutral components are then detected. The time of flight of the components are recorded and can be used to analyze the predecessor of the components, and therefore the specimen material. When more than one ion particle is emitted from the specimen per single ion impact, the single event time of flight mass spectrometer described here furnis This invention was made with Government support under Contract No. W-7405-ENG82 awarded by the Department of Energy. The Government has certain rights in the invention.

Conzemius, Robert J. (Ames, IA)

1990-01-16

334

MALDI-TOF-MS-based species identification and typing approaches in medical mycology.  

PubMed

MALDI-TOF MS-based species identification has found its place in many clinical routine diagnostic laboratories over the past years. Several well-established commercial systems exist and these allow precise analyses not only among bacteria, but also among clinically important yeasts. This methodology shows higher precision than biochemical and microscopic methods at significantly reduced turnaround times. Furthermore, the differentiation of different filamentous fungi including most dermatophytes and zygomycetes has been established. The direct identification of yeasts from blood culture bottles will be possible in a routine fashion with new standardized procedures. In addition to species identification, the MALDI-TOF MS technology offers several further possibilities, like assays to detect or predict resistance phenotypes in fungi as well as subtyping approaches to detect clinically relevant subgroups. The differences between the commercial systems are discussed with respect to fungi and an overview of their performances provided. Factors influencing outcome of MALDI-TOF-based species identification are discussed. PMID:23281257

Bader, Oliver

2013-03-01

335

Evaluation of the Andromas Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Identification of Aerobically Growing Gram-Positive Bacilli  

PubMed Central

Matrix-associated laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) is a rapid and simple microbial identification method. Previous reports using the Biotyper system suggested that this technique requires a preliminary extraction step to identify Gram-positive rods (GPRs), a technical issue that may limit the routine use of this technique to identify pathogenic GPRs in the clinical setting. We tested the accuracy of the MALDI-TOF MS Andromas strategy to identify a set of 659 GPR isolates representing 16 bacterial genera and 72 species by the direct colony method. This bacterial collection included 40 C. diphtheriae, 13 C. pseudotuberculosis, 19 C. ulcerans, and 270 other Corynebacterium isolates, 32 L. monocytogenes and 24 other Listeria isolates, 46 Nocardia, 75 Actinomyces, 18 Actinobaculum, 11 Propionibacterium acnes, 18 Propionibacterium avidum, 30 Lactobacillus, 21 Bacillus, 2 Rhodococcus equi, 2 Erysipelothrix rhusiopathiae, and 38 other GPR isolates, all identified by reference techniques. Totals of 98.5% and 1.2% of non-Listeria GPR isolates were identified to the species or genus level, respectively. Except for L. grayi isolates that were identified to the species level, all other Listeria isolates were identified to the genus level because of highly similar spectra. These data demonstrate that rapid identification of pathogenic GPRs can be obtained without an extraction step by MALDI-TOF mass spectrometry. PMID:22692743

Farfour, E.; Leto, J.; Barritault, M.; Barberis, C.; Meyer, J.; Dauphin, B.; Le Guern, A.-S.; Leflèche, A.; Badell, E.; Guiso, N.; Leclercq, A.; Le Monnier, A.; Lecuit, M.; Rodriguez-Nava, V.; Bergeron, E.; Raymond, J.; Vimont, S.; Bille, E.; Carbonnelle, E.; Guet-Revillet, H.; Lécuyer, H.; Beretti, J.-L.; Vay, C.; Berche, P.; Ferroni, A.; Nassif, X.

2012-01-01

336

Evaluation of the Andromas matrix-assisted laser desorption ionization-time of flight mass spectrometry system for identification of aerobically growing Gram-positive bacilli.  

PubMed

Matrix-associated laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a rapid and simple microbial identification method. Previous reports using the Biotyper system suggested that this technique requires a preliminary extraction step to identify Gram-positive rods (GPRs), a technical issue that may limit the routine use of this technique to identify pathogenic GPRs in the clinical setting. We tested the accuracy of the MALDI-TOF MS Andromas strategy to identify a set of 659 GPR isolates representing 16 bacterial genera and 72 species by the direct colony method. This bacterial collection included 40 C. diphtheriae, 13 C. pseudotuberculosis, 19 C. ulcerans, and 270 other Corynebacterium isolates, 32 L. monocytogenes and 24 other Listeria isolates, 46 Nocardia, 75 Actinomyces, 18 Actinobaculum, 11 Propionibacterium acnes, 18 Propionibacterium avidum, 30 Lactobacillus, 21 Bacillus, 2 Rhodococcus equi, 2 Erysipelothrix rhusiopathiae, and 38 other GPR isolates, all identified by reference techniques. Totals of 98.5% and 1.2% of non-Listeria GPR isolates were identified to the species or genus level, respectively. Except for L. grayi isolates that were identified to the species level, all other Listeria isolates were identified to the genus level because of highly similar spectra. These data demonstrate that rapid identification of pathogenic GPRs can be obtained without an extraction step by MALDI-TOF mass spectrometry. PMID:22692743

Farfour, E; Leto, J; Barritault, M; Barberis, C; Meyer, J; Dauphin, B; Le Guern, A-S; Leflèche, A; Badell, E; Guiso, N; Leclercq, A; Le Monnier, A; Lecuit, M; Rodriguez-Nava, V; Bergeron, E; Raymond, J; Vimont, S; Bille, E; Carbonnelle, E; Guet-Revillet, H; Lécuyer, H; Beretti, J-L; Vay, C; Berche, P; Ferroni, A; Nassif, X; Join-Lambert, O

2012-08-01

337

The value of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in identifying clinically relevant bacteria: a comparison with automated microbiology system  

PubMed Central

Background Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been developed as a new-type soft ionization mass spectrometry in the recent year. Increasing number of clinical microbiological laboratories consider it as an innovate approach for bacterial identification. Methods A total of 876 clinical strains, comprising 52 species in 27 genus, were obtained from Fudan University Affiliated Zhongshan Hospital. We compared the identification accuracy of the Vitek MS system (bioMerieux, Marcy l’Etoile) to other conventional methods for bacterial identification. 16S rRNA gene sequencing was performed as a reference identification method in cases of discrepant results. Results The Vitek MS system consistently produced accurate results within minutes of loading, while conventional methods required several hours to produce identification results. Among the 876 isolates, the overall performance of Vitek MS was significantly better than the conventional method both for correct species identification (830, 94.7% vs. 746, 85.2%, respectively, P=0.000). Conclusions Compared to traditional identification methods, MALDI-TOF MS is a rapid, accurate and economical technique to enhance the clinical value of microorganism identification. PMID:24822117

Zhou, Chunmei; Huang, Shenglei; Shan, Yuzhang; Ye, Xiangru

2014-01-01

338

N-doped graphene: an alternative carbon-based matrix for highly efficient detection of small molecules by negative ion MALDI-TOF MS.  

PubMed

Gas-phase N-doped graphene (gNG) was synthesized by a modified thermal annealing method using gaseous melamine as nitrogen source and then for the first time applied as a matrix in negative ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for small molecule analysis. Unlike the complicated adducts produced in positive ion mode, MS spectra obtained on gNG matrix in negative ion mode was only featured by deprotonated molecule ion peaks without matrix interference. By the gNG assisted desorption/ionization (D/I) process, some applications were carried out on a wide range of low-molecular weight (MW) analytes including amino acids, fatty acids, peptides, anabolic androgenic steroids as well as anticancer drugs, with an extraordinary laser desorption/ionization (LDI) efficiency over traditional ?-cyano-4-hydroxycinnamic acid (CHCA) and other carbon-based materials in the negative ion detection mode. By comparison of a series of graphene-based matrixes, two main factors of matrix gNG were unveiled to play a decisive role in assisting negative ion D/I process: a well-ordered ?-conjugated system for laser absorption and energy transfer; pyridinic-doped nitrogen species functioning as deprotonation sites for proton capture on negative ionization. The good salt tolerance and high sensitivity allowed further therapeutic monitoring of anticancer drug nilotinib in the spiked human serum, a real case of biology. Signal response was definitely obtained between 1 mM and 1 ?M, meeting the demand of assessing drug level in the patient serum. This work creates a new application branch for nitrogen-doped graphene and provides an alternative solution for small molecule analysis. PMID:25137626

Min, Qianhao; Zhang, Xiaoxia; Chen, Xueqin; Li, Siyuan; Zhu, Jun-Jie

2014-09-16

339

Proteomics-based approach to detect and identify major allergens in processed peanuts by capillary LC-Q-TOF (MS/MS).  

PubMed

An MS-based method, combining reversed-phase capillary liquid chromatography (capillary LC) with quadrupole time-of-flight tandem mass spectrometry (nano-ESI Q-TOF MS/MS), was developed with the aim of identifying a set of peptides that can function as markers for peanut allergens. Emphasis was given to the identification of the three major peanut allergens Ara h 1, Ara h 2, and Ara h 3, because these proteins are considered to represent >30% of the total protein content of peanut and are directly relevant for the allergenic potential of this food. The analytical data obtained were used to perform databank searching in combination with de novo sequencing and led to the identification of a multitude of sequence tags for all three peanut allergens. Food processing such as roasting of peanuts is known to affect the stability of proteins and was shown to influence the detection of allergen sequence tags. The analysis of raw and roasted peanuts allowed the identification of five peanut-specific sequence tags that can function as markers of the specific allergenic proteins. For Ara h 1, two peptide markers were proposed, namely, VLEENAGGEQEER (m/z 786.88, charge 2+) and DLAFPGSGEQVEK (m/z 688.85, charge 2+), whereas for Ara h 2 only one peptide, RQQWELQGDR (m/z 439.23, charge 3+), was found to satisfy the required conditions. For Ara h 3, the two specific peptides, SPDIYNPQAGSLK (m/z 695.35, charge 2+) and SQSENFEYVAFK (m/z 724.84, charge 2+), were selected. Other peptides have been proposed as indicative for food processing. PMID:17474754

Chassaigne, Hubert; Nørgaard, Jørgen V; Hengel, Arjon J van

2007-05-30

340

Probing the 3-D Structure, Dynamics, and Stability of Bacterial Collagenase Collagen Binding Domain (apo- versus holo-) by Limited Proteolysis MALDI-TOF MS  

NASA Astrophysics Data System (ADS)

Pairing limited proteolysis and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) to probe clostridial collagenase collagen binding domain (CBD) reveals the solution dynamics and stability of the protein, as these factors are crucial to CBD effectiveness as a drug-delivery vehicle. MS analysis of proteolytic digests indicates initial cleavage sites, thereby specifying the less stable and highly accessible regions of CBD. Modulation of protein structure and stability upon metal binding is shown through MS analysis of calcium-bound and cobalt-bound CBD proteolytic digests. Previously determined X-ray crystal structures illustrate that calcium binding induces secondary structure transformation in the highly mobile N-terminal arm and increases protein stability. MS-based detection of exposed residues confirms protein flexibility, accentuates N-terminal dynamics, and demonstrates increased global protein stability exported by calcium binding. Additionally, apo- and calcium-bound CBD proteolysis sites correlate well with crystallographic B-factors, accessibility, and enzyme specificity. MS-observed cleavage sites with no clear correlations are explained either by crystal contacts of the X-ray crystal structures or by observed differences between Molecules A and B in the X-ray crystal structures. The study newly reveals the absence of the ?A strand and thus the very dynamic N-terminal linker, as corroborated by the solution X-ray scattering results. Cobalt binding has a regional effect on the solution phase stability of CBD, as limited proteolysis data implies the capture of an intermediate-CBD solution structure when cobalt is bound.

Sides, Cynthia R.; Liyanage, Rohana; Lay, Jackson O.; Philominathan, Sagaya Theresa Leena; Matsushita, Osamu; Sakon, Joshua

2012-03-01

341

Potential of gas chromatography-atmospheric pressure chemical ionization-time-of-flight mass spectrometry for the determination of sterols in human plasma.  

PubMed

The application of Gas Chromatography (GC)-Atmospheric Pressure Chemical Ionization (APCI)-Time-of-Flight Mass Spectrometry (TOF-MS) is presented for sterol analysis in human plasma. A commercial APCI interface was modified to ensure a well-defined humidity which is essential for controlled ionization. In the first step, optimization regarding flow rates of auxiliary gases was performed by using a mixture of model analytes. Secondly, the qualitative and quantitative analysis of sterols including oxysterols, cholesterol precursors, and plant sterols as trimethylsilyl-derivatives was successfully carried out. The characteristics of APCI together with the very good mass accuracy of TOF-MS data enable the reliable identification of relevant sterols in complex matrices. Linear calibration lines and plausible results for healthy volunteers and patients could be obtained whereas all mass signals were extracted with an extraction width of 20 ppm from the full mass data set. One advantage of high mass accuracy can be seen in the fact that from one recorded run any search for m/z can be performed. PMID:24463103

Matysik, S; Schmitz, G; Bauer, S; Kiermaier, J; Matysik, F-M

2014-04-11

342

Ion Trace Detection Algorithm to Extract Pure Ion Chromatograms to Improve Untargeted Peak Detection Quality for Liquid Chromatography/Time-of-Flight Mass Spectrometry-Based Metabolomics Data.  

PubMed

Able to detect known and unknown metabolites, untargeted metabolomics has shown great potential in identifying novel biomarkers. However, elucidating all possible liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS) ion signals in a complex biological sample remains challenging since many ions are not the products of metabolites. Methods of reducing ions not related to metabolites or simply directly detecting metabolite related (pure) ions are important. In this work, we describe PITracer, a novel algorithm that accurately detects the pure ions of a LC/TOF-MS profile to extract pure ion chromatograms and detect chromatographic peaks. PITracer estimates the relative mass difference tolerance of ions and calibrates the mass over charge (m/z) values for peak detection algorithms with an additional option to further mass correction with respect to a user-specified metabolite. PITracer was evaluated using two data sets containing 373 human metabolite standards, including 5 saturated standards considered to be split peaks resultant from huge m/z fluctuation, and 12 urine samples spiked with 50 forensic drugs of varying concentrations. Analysis of these data sets show that PITracer correctly outperformed existing state-of-art algorithm and extracted the pure ion chromatograms of the 5 saturated standards without generating split peaks and detected the forensic drugs with high recall, precision, and F-score and small mass error. PMID:25622715

Wang, San-Yuan; Kuo, Ching-Hua; Tseng, Yufeng J

2015-03-01

343

Screening natural antioxidants in peanut shell using DPPH-HPLC-DAD-TOF/MS methods.  

PubMed

Peanut shell, a byproduct in oil production, is rich in natural antioxidants. Here, a rapid and efficient method using DPPH-HPLC-DAD-TOF/MS was used for the first time to screen antioxidants in peanut shell. The method is based on the hypothesis that upon reaction with 1, 1-diphenyl-2-picrylhydrazyl (DPPH), the peak areas of compounds with potential antioxidant activities in the HPLC chromatogram will be significantly reduced or disappeared, and the identity confirmation could be achieved by HPLC-DAD-TOF/MS technique. With this method, three compounds possessing potential antioxidant activities were found abundantly in the methanolic extract of peanut shell. They were identified as 5,7-dihydroxychromone, eriodictyol, and luteolin. The contents of these compounds were 0.59, 0.92, and 2.36 mg/g, respectively, and luteolin possessed the strongest radical scavenging capacity. DPPH-HPLC-DAD-TOF/MS assay facilitated rapid identification and determination of natural antioxidants in peanut shell, which may be helpful for value-added utilization of peanut processing byproducts. PMID:22980814

Qiu, Jiying; Chen, Leilei; Zhu, Qingjun; Wang, Daijie; Wang, Wenliang; Sun, Xin; Liu, Xiaoyong; Du, Fangling

2012-12-15

344

Differentiating Organic and Conventional Sage by Chromatographic and Mass Spectrometry Flow-Injection Fingerprints Combined with Principal Component Analysis  

PubMed Central

High performance liquid chromatography (HPLC) and flow injection electrospray ionization with ion trap mass spectrometry (FIMS) fingerprints combined with the principal component analysis (PCA) were examined for their potential in differentiating commercial organic and conventional sage samples. The individual components in the sage samples were also characterized with an ultra-performance liquid chromatography with a quadrupole-time of flight mass spectrometer (UPLC Q-TOF MS). The results suggested that both HPLC and FIMS fingerprints combined with PCA could differentiate organic and conventional sage samples effectively. FIMS may serve as a quick test capable of distinguishing organic and conventional sages in 1 min, and could potentially be developed for high-throughput applications; whereas HPLC fingerprints could provide more chemical composition information with a longer analytical time. PMID:23464755

Gao, Boyan; Lu, Yingjian; Sheng, Yi; Chen, Pei; Yu, Liangli (Lucy)

2013-01-01

345

Differentiating organic and conventional sage by chromatographic and mass spectrometry flow injection fingerprints combined with principal component analysis.  

PubMed

High-performance liquid chromatography (HPLC) and flow injection electrospray ionization with ion trap mass spectrometry (FIMS) fingerprints combined with principal component analysis (PCA) were examined for their potential in differentiating commercial organic and conventional sage samples. The individual components in the sage samples were also characterized with an ultraperformance liquid chromatograph with a quadrupole-time-of-flight mass spectrometer (UPLC Q-TOF MS). The results suggested that both HPLC and FIMS fingerprints combined with PCA could differentiate organic and conventional sage samples effectively. FIMS may serve as a quick test capable of distinguishing organic and conventional sages in 1 min and could potentially be developed for high-throughput applications, whereas HPLC fingerprints could provide more chemical composition information with a longer analytical time. PMID:23464755

Gao, Boyan; Lu, Yingjian; Sheng, Yi; Chen, Pei; Yu, Liangli Lucy

2013-03-27

346

Evaluation of Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Second-Generation Lignin Analysis  

PubMed Central

Matrix-Assisted Laser Desorption/Ionization time-of-flight (MALDI-TOF) mass spectrometry is evaluated as an elucidation tool for structural features and molecular weights estimation of some extracted herbaceous lignins. Optimization of analysis conditions, using a typical organic matrix, namely ?-cyano-4-hydroxycinnamic acid (CHCA), in combination with ?-cyclodextrin, allows efficient ionization of poorly soluble lignin materials and suppression of matrix-related ions background. Analysis of low-mass fragments ions (m/z 100–600) in the positive ion mode offers a “fingerprint” of starting lignins that could be a fine strategy to qualitatively identify principal inter-unit linkages between phenylpropanoid units. The molecular weights of lignins are estimated using size exclusion chromatography and compared to MALDI-TOF-MS profiles. Miscanthus (Miscanthus x giganteus) and Switchgrass (Panicum Virgatum L.) lignins, recovered after a formic acid/acetic acid/water process or aqueous ammonia soaking, are selected as benchmarks for this study. PMID:23300342

Richel, Aurore; Vanderghem, Caroline; Simon, Mathilde; Wathelet, Bernard; Paquot, Michel

2012-01-01

347

Metabolic profile of miltirone in rats by high performance liquid chromatography/quadrupole time-of-flight mass spectrometry.  

PubMed

Miltirone is one of the bioactive diterpene quinones isolated from Salvia miltiorrhiza Bunge. This compound has been found to possess significant anticancer, antibacterial, antioxidant, and anti-inflammatory activities. However, the metabolic fate of miltirone remains unknown. In order to explore whether miltirone is extensively metabolized, we investigated the metabolites of miltirone in plasma, bile, urine, and feces samples following oral and intravenous administration to the rats. By using high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (HPLC/Q-TOF-MS) coupled with mass detect filter (MDF) method, a total of 15 metabolites were identified from the biosamples. Both phase I and phase II metabolites were observed in the metabolic profile and the metabolic pathways involved in reduction, oxidation, monohydroxylation, dihydroxylation, glucuronidation and sulfation. The results indicated that hepatocyte metabolism was the major route of clearance for the parent compound. The present study provided valuable information for better understanding of the efficacy and safety of miltirone. PMID:25679091

Guo, Long; Duan, Li; Dong, Xin; Dou, Li-Li; Zhou, Ping; Li, Ping; Liu, E-Hu

2015-03-25

348

Undisturbed and disturbed above canopy ponderosa pine emissions: PTR-TOF-MS measurements and MEGAN 2.1 model results  

NASA Astrophysics Data System (ADS)

We present the first eddy covariance flux measurements of volatile organic compounds (VOCs) using a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) above a ponderosa pine forest in Colorado, USA. The high mass resolution of the PTR-TOF-MS enabled the identification of chemical sum formulas. During a 30 day measurement period in August and September 2010, 649 different ion mass peaks were detected in the ambient air mass spectrum (including primary ions and mass calibration compounds). Eddy covariance with the vertical wind speed was calculated for all ion mass peaks. On a typical day, 17 ion mass peaks, including protonated parent compounds, their fragments and isotopes as well as VOC-H+-water clusters, showed a significant flux with daytime average emissions above a reliable flux threshold of 0.1 mg compound m-2 h-1. These ion mass peaks could be assigned to seven compound classes. The main flux contributions during daytime (10:00-18:00 LT) are attributed to the sum of 2-methyl-3-buten-2-ol (MBO) and isoprene (50%), methanol (12%), the sum of acetic acid and glycolaldehyde (10%) and the sum of monoterpenes (10%). The total MBO + isoprene flux was composed of 10% isoprene and 90% MBO. There was good agreement between the light- and temperature dependency of the sum of MBO and isoprene observed for this work and those of earlier studies. The above canopy flux measurements of the sum of MBO and isoprene and the sum of monoterpenes were compared to emissions calculated using the Model of Emissions of Gases and Aerosols from Nature (MEGAN 2.1). The best agreement between MEGAN 2.1 and measurements was reached using emission factors determined from site-specific leaf cuvette measurements. While the modeled and measured MBO + isoprene fluxes agree well, the emissions of the sum of monoterpenes is underestimated by MEGAN 2.1. This is expected as some factors impacting monoterpene emissions, such as physical damage of needles and branches due to storms, are not included in MEGAN 2.1. After a severe hailstorm event, 22 ion mass peaks (attributed to six compound classes plus some unknown compounds) showed an elevated flux for the two following days. The sum of monoterpene emissions was 4-23 times higher compared to emissions prior to the hailstorm while MBO emissions remained unchanged. The monoterpene emission (in mg compound m-2) during this measurement period is underestimated by 40% if the effect of this disturbance source is not considered.

Kaser, L.; Karl, T.; Guenther, A.; Graus, M.; Schnitzhofer, R.; Turnipseed, A.; Fischer, L.; Harley, P.; Madronich, M.; Gochis, D.; Keutsch, F. N.; Hansel, A.

2013-12-01

349

Phylogenetic analysis of microalgae based on highly abundant proteins using mass spectrometry.  

PubMed

The blooms of toxic phototrophic microorganisms, such as microalgae and cyanobacteria, which are typically found in freshwater and marine environments, are becoming more frequent and problematic in aquatic systems. Due to accumulation of toxic algae, harmful algal blooms (HABs) exert negative effects on aquatic systems. Therefore, rapid detection of harmful microalgae is important for monitoring the occurrence of HABs. Mass spectrometry-based methods have become sensitive, specific techniques for the identification and characterization of microorganisms. Matrix-assisted laser desorption/ionization (MALDI) with time-of-flight (TOF) mass spectrometry (MS) allows us to measure a unique molecular fingerprint of highly abundant proteins in a microorganism and has been used for the rapid, accurate identification of bacteria and fungi in clinical microbiology. Here, we tested the specificity of MALDI-TOF MS using microalgal strains (Heterocapsa, Alexandrium, Nannochloropsis, Chaetoceros, Chlorella, and Dunaliella spp.). Our research suggested that this method was comparable in terms of the rapid identification of microalgea to conventional methods based on genetic information and morphology. Thus, this efficient mass spectrometry-based technique may have applications in the rapid identification of harmful microorganisms from aquatic environmental samples. PMID:25476355

Lee, Hae-Won; Roh, Seong Woon; Cho, Kichul; Kim, Kil-Nam; Cha, In-Tae; Yim, Kyung June; Song, Hye Seon; Nam, Young-Do; Oda, Tatsuya; Chung, Young-Ho; Kim, Soo Jung; Choi, Jong-Soon; Kim, Daekyung

2015-01-01

350

Sequencing regular and labeled oligonucleotides using enzymatic digestion and ionspray mass spectrometry.  

PubMed

A method using a combination of enzymatic digestion and ionspray mass spectrometry (MS) was developed for sequencing oligodeoxynucleotides (ODNs) containing more than 20 bases. Phosphodiesterase (PDE) digestion of ODNs produced truncated ODNs whose molecular weights (MWs) were determined by ionspray MS. It was demonstrated that reconstruction of MW spectra over a large MW range produced easy-to-read sequence ladders similar to those obtained using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Sample and enzyme cleanup, digestion control, and MW reconstruction were found to be crucial factors. For regular ODNs, both 5'- and 3'-PDE digestions are needed for complete sequencing. Late in the time course of PDE digestions, 5'-nucleoside monophosphates were found to produce artifactual peaks in the reconstructed MW spectra, and a table correlating base compositions and MS ions was compiled to handle such situations. For labeled ODNs, it is necessary to use collision-induced dissociation-tandem mass spectrometry (CID-MS/MS) for complete sequence determination. Sequencing of regular 22-mer and labeled 18-mer ODNs was demonstrated in this work. PMID:9799524

Wu, H; Chan, C; Aboleneen, H

1998-10-15

351

X-ray sequence ambiguities of Sclerotium rolfsii lectin resolved by mass spectrometry.  

PubMed

X-ray crystallography, although a powerful technique for determining the three-dimensional structure of proteins, poses inherent problems in assigning the primary structure in residues Asp/Asn and Glu/Gln since these cannot be distinguished decisively in the electron density maps. In our recently published X-ray crystal structure of the Sclerotium rolfsii lectin (SRL) at 1.1 A resolution, amino acid sequence was initially deduced from the electron density map and residues Asp/Asn and Glu/Gln were assigned by considering their hydrogen bonding potential within their structural neighborhood. Attempts to verify the sequence by Edman sequencing were not successful as the N terminus of the protein was blocked. Mass spectrometry was applied to verify and resolve the ambiguities in the SRL X-ray crystal structure deduced sequence. From the Matrix assisted laser desorption/ionization time-of-flight-mass spectrometry (MALDI TOF-MS) and liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis of tryptic and chymotryptic peptides of SRL, we could confirm and correct the sequence at five locations with respect to Asp/Asn and Glu/Gln. Analysis data also confirmed the positions of Leu/Ile, Gln/Lys residues and the sequence covering 118 of the total 141 residues accounting to 83.68% of the earlier deduced sequence of SRL. PMID:18163177

Sathisha, G J; Prakash, Y K Subrahmanya; Chachadi, V B; Nagaraja, N N; Inamdar, S R; Leonidas, D D; Savithri, H S; Swamy, B M

2008-08-01

352

A simple algorithm improves mass accuracy to 50-100 ppm for delayed extraction linear MALDI-TOF mass spectrometry  

SciTech Connect

A simple mathematical technique for improving mass calibration accuracy of linear delayed extraction matrix assisted laser desorption ionization time-of-flight mass spectrometry (DE MALDI-TOF MS) spectra is presented. The method involves fitting a parabola to a plot of Dm vs. mass data where Dm is the difference between the theoretical mass of calibrants and the mass obtained from a linear relationship between the square root of m/z and ion time of flight. The quadratic equation that describes the parabola is then used to correct the mass of unknowns by subtracting the deviation predicted by the quadratic equation from measured data. By subtracting the value of the parabola at each mass from the calibrated data, the accuracy of mass data points can be improved by factors of 10 or more. This method produces highly similar results whether or not initial ion velocity is accounted for in the calibration equation; consequently, there is no need to depend on that uncertain parameter when using the quadratic correction. This method can be used to correct the internally calibrated masses of protein digest peaks. The effect of nitrocellulose as a matrix additive is also briefly discussed, and it is shown that using nitrocellulose as an additive to a CHCA matrix does not significantly change initial ion velocity but does change the average position of ions relative to the sample electrode at the instant the extraction voltage is applied.

Hack, Christopher A.; Benner, W. Henry

2001-10-31

353

Isotope dilution mass spectrometry  

NASA Astrophysics Data System (ADS)

In the past isotope dilution mass spectrometry (IDMS) has usually been applied using the formation of positive thermal ions of metals. Especially in calibrating other analytical methods and for the certification of standard reference materials this type of IDMS became a routine method. Today, the progress in this field lies in the determination of ultra trace amounts of elements, e.g. of heavy metals in Antarctic ice and in aerosols in remote areas down to the sub-pg g-1 and sub-pg m-3 levels respectively, in the analysis of uranium and thorium at concentrations of a few pg g-1 in sputter targets for the production of micro- electronic devices or in the determination of sub-picogram amounts of230Th in corals for geochemical age determinations and of226Ra in rock samples. During the last few years negative thermal ionization IDMS has become a frequently used method. The determination of very small amounts of selenium and technetium as well as of other transition metals such as vanadium, chromium, molybdenum and tungsten are important examples in this field. Also the measurement of silicon in connection with a re-determination of Avogadro's number and osmium analyses for geological age determinations by the Re/Os method are of special interest. Inductively-coupled plasma mass spectrometry is increasingly being used for multi-element analyses by the isotope dilution technique. Determinations of heavy metals in samples of marine origin are representative examples for this type of multi-element analysis by IDMS. Gas chromatography-mass spectrometry systems have also been successfully applied after chelation of metals (for example Pt determination in clinical samples) or for the determination of volatile element species in the environment, e.g. dimethyl sulfide. However, IDMS--specially at low concentration levels in the environment--seems likely to be one of the most powerful analytical methods for speciation in the future. This has been shown, up to now, for species of iodine, selenium and some heavy metals in aquatic systems.

Heumann, Klaus G.

1992-09-01

354

Matrix-Assisted Laser Desorption Ionization: Time of Flight Mass Spectrometry-Identified Models for Detection of ESBL-Producing Bacterial Strains  

PubMed Central

Background The increase in the amount of extended spectrum beta-lactamases (ESBL)-producing gram-negative bacteria is seriously threatening human health in recent years. Therefore, it is necessary to develop a rapid and reliable method for identification of ESBLs. The purpose of this study was to establish a novel method to discriminate between ESBL-producing and non- ESBL-producing bacteria by using the matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) technique. Material/Methods We detected hydrolyzed production of cefotaxime after incubation with 69 gram-negative bacteria by using MALDI-TOF-MS. Then we established genetic algorithm (GA), supervised neural networks (SNN), and quick classifier (QC) models using several peaks to identify ESBL-producing strains. To confirm the clinical applicability of the models established, a blinded validation test was performed in 34 clinical isolated strains. Results Using ClinPro Tools software, we identified 4 peaks (456 Da, 396 Da, 370 Da, and 371 Da) in mass spectra of cefotaxime solution that have high enough specificity to discriminate ESBL-producing from non- ESBL-producing strains. Recognition capability of models established were 97.5% (GA), 92.5% (SNN), and 92.5% (QC), and cross validation rates were 90.15% (GA), 97.62 (SNN), and 97.62% (QC). The accuracy rates of the blinded validation test were 82.4% (GA), 88.2% (SNN), and 82.4% (QC). Conclusions Our results demonstrate that identification of ESBLs strains by MALDI-TOF-MS has potential clinical value and could be widely used in the future as a routine test in clinical microbiology laboratories. PMID:25390932

Li, Bo; Guo, Tongsheng; Qu, Fen; Li, Boan; Wang, Haibin; Sun, Zhiqiang; Li, Xiaohan; Gao, Zhiqiang; Bao, Chunmei; Zhang, Chenglong; Li, Xiaoxi; Mao, Yuanli

2014-01-01

355

Leptospira species and serovars identified by MALDI-TOF mass spectrometry after database implementation  

PubMed Central

Background Leptospirosis, a spirochaetal zoonotic disease of worldwide distribution, endemic in Europe, has been recognized as an important emerging infectious disease, though yet it is mostly a neglected disease which imparts its greatest burden on impoverished populations from developing countries. Leptospirosis is caused by the infection with any of the more than 230 serovars of pathogenic Leptospira sp. In this study we aimed to implement the MALDI-TOF mass spectrometry (MS) database currently available in our laboratory with Leptospira reference pathogenic (L. interrogans, L. borgpetersenii, L. kirschneri, L. noguchii), intermediate (L. fainei) and saprophytic (L. biflexa) strains of our collection in order to evaluate its possible application to the diagnosis of leptospirosis and to the typing of strains. This was done with the goal of understanding whether this methodology could be used as a tool for the identification of Leptospira strains, not only at species level for diagnostic purposes, but also at serovar level for epidemiological purposes, overcoming the limits of serological and molecular conventional methods. Twenty Leptospira reference strains were analysed by MALDI-TOF MS. Statistical analysis of the protein spectra was performed by ClinProTools software. Results The spectra obtained by the analysis of the reference strains tested were grouped into 6 main classes corresponding to the species analysed, highlighting species-specific protein profiles. Moreover, the statistical analysis of the spectra identified discriminatory peaks to recognize Leptospira strains also at serovar level extending previously published data. Conclusions In conclusion, we confirmed that MALDI-TOF MS could be a powerful tool for research and diagnostic in the field of leptospirosis with broad applications ranging from the detection and identification of pathogenic leptospires for diagnostic purposes to the typing of pathogenic and non-pathogenic leptospires for epidemiological purposes in order to enrich our knowledge about the epidemiology of the infection in different areas and generate control strategies. PMID:24890024

2014-01-01

356

Ovarian cancer detection from metabolomic liquid chromatography/mass spectrometry data by support vector machines  

PubMed Central

Background The majority of ovarian cancer biomarker discovery efforts focus on the identification of proteins that can improve the predictive power of presently available diagnostic tests. We here show that metabolomics, the study of metabolic changes in biological systems, can also provide characteristic small molecule fingerprints related to this disease. Results In this work, new approaches to automatic classification of metabolomic data produced from sera of ovarian cancer patients and benign controls are investigated. The performance of support vector machines (SVM) for the classification of liquid chromatography/time-of-flight mass spectrometry (LC/TOF MS) metabolomic data focusing on recognizing combinations or "panels" of potential metabolic diagnostic biomarkers was evaluated. Utilizing LC/TOF MS, sera from 37 ovarian cancer patients and 35 benign controls were studied. Optimum panels of spectral features observed in positive or/and negative ion mode electrospray (ESI) MS with the ability to distinguish between control and ovarian cancer samples were selected using state-of-the-art feature selection methods such as recursive feature elimination and L1-norm SVM. Conclusion Three evaluation processes (leave-one-out-cross-validation, 12-fold-cross-validation, 52-20-split-validation) were used to examine the SVM models based on the selected panels in terms of their ability for differentiating control vs. disease serum samples. The statistical significance for these feature selection results were comprehensively investigated. Classification of the serum sample test set was over 90% accurate indicating promise that the above approach may lead to the development of an accurate and reliable metabolomic-based approach for detecting ovarian cancer. PMID:19698113

Guan, Wei; Zhou, Manshui; Hampton, Christina Y; Benigno, Benedict B; Walker, L DeEtte; Gray, Alexander; McDonald, John F; Fernández, Facundo M

2009-01-01

357

Glycomics and Mass Spectrometry  

NASA Astrophysics Data System (ADS)

There is an increasing body of evidence indicating that glycans are implicated in numerous biological processes such as cell-cell interactions, intracellular signaling, and immune response. Glycomics emerges from the necessity to understand the mechanisms underlying the interactions responsible for these activities. The term glycomics is used to describe experimental approaches to studying the structure and function of the glycomes of fluids, cells, tissues, organs etc. Glycomics embraces a variety of technologies amongst which mass spectrometry (MS) plays a pivotal role because it is the method of choice for defining the primary structures of glycopolymers. This chapter provides an insight into MS -based structural strategies that are best suited to studying complex glycomes.

Dell, Anne; Jang-Lee, Jihye; Pang, Poh-Choo; Parry, Simon; Sutton-Smith, Mark; Tissot, Berangere; Morris, Howard R.; Panico, Maria; Haslam, Stuart M.

358

Proteome Analysis by Mass Spectrometry  

Microsoft Academic Search

The coupling of high-performance mass spectrometry instrumentation with highly efficient chromatographic and electrophoretic separations has enabled rapid qualitative and quantitative analysis of thousands of proteins from minute samples of biological materials. Here, we review recent progress in the development and application of mass spectrometry-based techniques for the qualitative and quantitative analysis of global proteome samples. Techniques such as multidimensional peptide

Patrick L. Ferguson; Richard D. Smith

2003-01-01

359

Guanidination of tryptic peptides without desalting for matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry analysis.  

PubMed

Derivatizations that enhance mass spectral quality often require desalting, which presents as a bottleneck in matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS)-proteomics. Guanidination, which converts lysine to homoarginine, an arginine analogue, can increase detection of those peptides 5-15-fold. Our aim was to improve guanidination by using a novel reagent, O-methylisourea-freebase. In a simple reaction, interfering salts were removed prior to guanidination. Freebase preparation took about 30 min and could be applied to samples all at once as opposed to desalting samples one-by-one for 5 min each. For freebase guanidinated BSA tryptic peptides, more than 6-times the peptides were observed relative to tryptic peptides or those guanidinated with the conventional reagent, O-methylisourea hemisulfate. Peptide signals increased more than 10-fold relative to those from guanidination with the conventional reagent and were equivalent to those from conventional guanidination with desalting. In addition, freebase guanidination allowed for a lower limit of detection when combined with another derivatization, N-terminal sulfonation, as evidenced by tandem mass spectrometry (MS/MS) fragmentation analysis of in-gel digests of cytochrome c. Freebase guanidination of rat lung proteins after 2-D gel electrophoresis allowed for identification of all tested protein spots regardless of protein characteristics (MW or pI) or abundance. Co-derivatization with N-terminal sulfonation confirmed the identity of low-abundance proteins in 2-D gel spots that contained more than one protein. The freebase guanidination reagent is simple to prepare and to implement. Desalting is not needed prior to MALDI-TOF MS. Freebase guanidination effectively increases the dynamic range of detection of lysine-containing peptides while decreasing the work needed for sample preparation. PMID:23964694

Baker, Margaret R; Li, Qing X

2013-09-17

360

Rapid determination of pesticide residues in fruits and vegetables, using ultra-high-performance liquid chromatography/time-of-flight mass spectrometry.  

PubMed

A multiresidue method, based on the sample preparation by solid-phase extraction cartridges and detection by ultra-high-performance liquid chromatography/time-of-flight mass spectrometry (UHPLC/TOF-MS), was used for the analysis of 60 pesticides in vegetable and fruit samples. Quantitation by UHPLC/TOF-MS is accomplished by measuring the accurate mass of the protonated molecules [M+H](+). The mass accuracy typically obtained is routinely better than 2ppm. The rates of recovery for pesticides studied were satisfactory, ranging from 74% to 111% with a relative standard deviation (RSD) of less than 13.2%, at concentrations below 10?gkg(-1). The method limit of quantification (MLOQ) for most compounds was below the MRLs established by the Food Safety Standard Authority of India and the European Union. The uncertainty was determined using repeatability, recovery and calibration curves data for each pesticide. The method illustrated is suitable for routine quantitative analyses of pesticides in food samples. PMID:25172721

Sivaperumal, P; Anand, P; Riddhi, L

2015-02-01

361

Identification of Bacteria in Blood Culture Broths Using Matrix-Assisted Laser Desorption-Ionization Sepsityper™ and Time of Flight Mass Spectrometry  

PubMed Central

Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) is a novel method for the direct identification of bacteria from blood culture broths. We evaluate for the first time, the performance of the MALDI Sepsityper™ Kit and MS for the identification of bacteria compared to standard phenotypic methods using the manufacturer's specified bacterial identification criteria (spectral scores ?1.700–1.999 and ?2.000 indicated identification to genus and species level, respectively). Five hundred and seven positive blood culture broths were prospectively examined, of which 379 (74.8%; 358 monomicrobial, 21 polymicrobial) were identified by MALDI-TOF MS; 195 (100%) and 132 (67.7%) of 195 gram-positive; and 163 (100%) and 149 (91.4%) of 163 gram-negative organisms from monomicrobial blood cultures were correctly identified to genus and species level, respectively. Spectral scores <1.700 (no identification) were obtained in 128/507 (25.2%) positive blood culture broths, including 31.6% and 32.3% of gram-positive and polymicrobial blood cultures, respectively. Significantly more gram-negative organisms were identified compared to gram-positive organisms at species level (p<0.0001). Five blood cultures were misidentified, but at species level only; including four monomicrobial blood cultures with Streptococcus oralis/mitis that were misidentified as Streptococcus pneumoniae. Positive predictive values for the direct identification of both gram-positive and gram-negative bacteria from monomicrobial blood culture broths to genus level were 100%. A diagnostic algorithm for positive blood culture broths that incorporates gram staining and MALDI-TOF MS should identify the majority of pathogens, particularly to genus level. PMID:21858058

Kok, Jen; Thomas, Lee C.; Olma, Thomas; Chen, Sharon C. A.; Iredell, Jonathan R.

2011-01-01

362

Chemical Analysis of the Chinese Liquor Luzhoulaojiao by Comprehensive Two-Dimensional Gas Chromatography/Time-of-Flight Mass Spectrometry  

PubMed Central

Luzhoulaojiao liquor is a type of Chinese liquor that dates back hundreds of years, but whose precise chemical composition remains unknown. This paper describes the screening of the liquor and the identification of its compounds using comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC/TOF-MS). Samples were prepared by both liquid-liquid extraction and solid-phase microextraction, which facilitated the detection of thousands of compounds in the liquor, thus demonstrating the superior performance of the proposed method over those reported in previous studies. A total of 320 compounds were common to all 18 types of Luzhoulaojiao liquor studied here, and 13 abundant and potentially bioactive compounds were further quantified. The results indicated that the high-performance method presented here is well suited for the detection and identification of compounds in liquors. This study also contributes to enriching our knowledge of the contents of Chinese liquors. PMID:25857434

Yao, Feng; Yi, Bin; Shen, Caihong; Tao, Fei; Liu, Yumin; Lin, Zhixin; Xu, Ping

2015-01-01

363

Chemical Analysis of the Chinese Liquor Luzhoulaojiao by Comprehensive Two-Dimensional Gas Chromatography/Time-of-Flight Mass Spectrometry.  

PubMed

Luzhoulaojiao liquor is a type of Chinese liquor that dates back hundreds of years, but whose precise chemical composition remains unknown. This paper describes the screening of the liquor and the identification of its compounds using comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC/TOF-MS). Samples were prepared by both liquid-liquid extraction and solid-phase microextraction, which facilitated the detection of thousands of compounds in the liquor, thus demonstrating the superior performance of the proposed method over those reported in previous studies. A total of 320 compounds were common to all 18 types of Luzhoulaojiao liquor studied here, and 13 abundant and potentially bioactive compounds were further quantified. The results indicated that the high-performance method presented here is well suited for the detection and identification of compounds in liquors. This study also contributes to enriching our knowledge of the contents of Chinese liquors. PMID:25857434

Yao, Feng; Yi, Bin; Shen, Caihong; Tao, Fei; Liu, Yumin; Lin, Zhixin; Xu, Ping

2015-01-01

364

Application the mass spectrometry MALDI-TOF technique for detection of Babesia canis canis infection in dogs.  

PubMed

The aim of this study was to use rapid mass spectrometry (MS)-based proteomics analyses for diagnosis of Babesia canis canis infections in dogs. The study was conducted on two groups of dogs--healthy dogs and dogs infected with B. canis canis which demonstrated symptoms of babesiosis. The matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) MS technique revealed the presence of a protein fraction of 51-52 kDa in the blood serum of all the animals infected with the protozoa, which was not found in the serum of healthy dogs. The proteins are suspected to be disease markers, whereas the MALDI-TOF technique itself has high specificity and sensitivity and can be applied in analytical laboratories in the diagnosis of canine babesiosis. PMID:25238794

Adaszek, ?ukasz; Banach, Tomasz; Bartnicki, Micha?; Winiarczyk, Dagmara; ?yp, Pawe?; Winiarczyk, Stanis?aw

2014-11-01

365

Rapid Identification and Subtyping of Helicobacter cinaedi Strains by Intact-Cell Mass Spectrometry Profiling with the Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry  

PubMed Central

Helicobacter cinaedi infection is recognized as an increasingly important emerging disease in humans. Although H. cinaedi-like strains have been isolated from a variety of animals, it is difficult to identify particular isolates due to their unusual phenotypic profiles and the limited number of biochemical tests for detecting helicobacters. Moreover, analyses of the 16S rRNA gene sequences are also limited due to the high levels of similarity among closely related helicobacters. This study was conducted to evaluate intact-cell mass spectrometry (ICMS) profiling using matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) as a tool for the identification of H. cinaedi. A total of 68 strains of H. cinaedi isolated from humans, dogs, a cat, and hamsters were examined in addition to other Helicobacter species. The major ICMS profiles of H. cinaedi were identical and differed from those of Helicobacter bilis, which show >98% sequence similarity at the 16S rRNA sequence level. A phyloproteomic analysis of the H. cinaedi strains examined in this work revealed that human isolates formed a single cluster that was distinct from that of the animal isolates, with the exception of two strains from dogs. These phyloproteomic results agreed with those of the phylogenetic analysis based on the nucleotide sequences of the hsp60 gene. Because they formed a distinct cluster in both analyses, our data suggest that animal strains may not be a major source of infection in humans. In conclusion, the ICMS profiles obtained using a MALDI-TOF MS approach may be useful for the identification and subtyping of H. cinaedi. PMID:24153128

Taniguchi, Takako; Sekiya, Ayumi; Higa, Mariko; Saeki, Yuji; Umeki, Kazumi; Okayama, Akihiko; Hayashi, Tetsuya

2014-01-01

366

Optimal extraction and fingerprint analysis of Cnidii fructus by accelerated solvent extraction and high performance liquid chromatographic analysis with photodiode array and mass spectrometry detections.  

PubMed

A confirmatory and reliable procedure has been developed for extraction and determination of Cnidii fructus by accelerated solvent extraction (ASE) and high-performance liquid chromatography coupled with photodiode array, electrospray ionisation ion trap tandem mass spectrometry and time of flight mass spectrometry (HPLC-PDA-ESI-ITMS(n)/TOF-MS). The determination method enabled the characterisation of sixteen bioactive components in C. fructus and quantification of three major coumarins, namely osthole, imperatorin and isopimpinellin. Response surface methodology (RSM) was employed to optimise the extraction parameters yielding the optimum conditions of ASE (extraction temperature 122 °C, extraction time 5 min and two static cycles). And the total contents of three major coumarins extracted by ASE under the optimum conditions was significantly higher than those by reflux and ultrasonic extraction (P<0.05) with better reproducibility. At last, the proposed method coupled with pattern recognition was applied to analysis of C. fructus from eight different regions in China. PMID:23870916

Gao, Fangyuan; Hu, Yongsheng; Ye, Xiaolan; Li, Ji; Chen, Zhao; Fan, Guorong

2013-12-01

367

Mass Spectrometry in the Postgenomic Era  

E-print Network

Mass Spectrometry in the Postgenomic Era Brian T. Chait Laboratory for Mass Spectrometry spectrometry, lipidomics Abstract Mass spectrometry (MS) is rapidly becoming an essential tool for bi- ologists building blocks after frag- mentation (1). Historically, this simple mass spectrometry (MS) approach proved

Chait, Brian T.

368

A computational drug metabolite detection using the stable isotopic mass-shift filtering with high resolution mass spectrometry in pioglitazone and flurbiprofen.  

PubMed

The identification of metabolites in drug discovery is important. At present, radioisotopes and mass spectrometry are both widely used. However, rapid and comprehensive identification is still laborious and difficult. In this study, we developed new analytical software and employed a stable isotope as a tool to identify drug metabolites using mass spectrometry. A deuterium-labeled compound and non-labeled compound were both metabolized in human liver microsomes and analyzed by liquid chromatography/time-of-flight mass spectrometry (LC-TOF-MS). We computationally aligned two different MS data sets and filtered ions having a specific mass-shift equal to masses of labeled isotopes between those data using our own software. For pioglitazone and flurbiprofen, eight and four metabolites, respectively, were identified with calculations of mass and formulas and chemical structural fragmentation analysis. With high resolution MS, the approach became more accurate. The approach detected two unexpected metabolites in pioglitazone, i.e., the hydroxypropanamide form and the aldehyde hydrolysis form, which other approaches such as metabolite-biotransformation list matching and mass defect filtering could not detect. We demonstrated that the approach using computational alignment and stable isotopic mass-shift filtering has the ability to identify drug metabolites and is useful in drug discovery. PMID:24084721

Uchida, Masashi; Kanazawa, Mitsuhiro; Ogiwara, Atsushi; Sezaki, Hiroshi; Ando, Akihiro; Miyamoto, Yohei

2013-01-01

369

Mass Spectrometry and Protein Analysis  

NSDL National Science Digital Library

Mass spectrometry is a central analytical technique for protein research and for the study of biomolecules in general. Driven by the need to identify, characterize, and quantify proteins at ever increasing sensitivity and in ever more complex samples, a wide range of new mass spectrometryâ??based analytical platforms and experimental strategies have emerged. Here we review recent advances in mass spectrometry instrumentation in the context of current and emerging research strategies in protein science.

Bruno Domon (ETH Zurich; Institute of Molecular Systems Biology)

2006-04-14

370

Toward the Complete Characterization of Atmospheric Organic Particulate Matter: Derivatization and Two-Dimensional Comprehensive Gas Chromatography/Time of Flight Mass Spectrometry as a Method for the Determination of Carboxylic Acids  

NASA Astrophysics Data System (ADS)

Understanding the composition of atmospheric organic particulate matter (OPM) is essential for predicting its effects on climate, air quality, and health. However, the polar oxygenated fraction (PO-OPM), which includes a significant mass contribution from carboxylic acids, is difficult to speciate and quantitatively determine by current analytical methods such as gas chromatography-mass spectrometry (GC-MS). The method of chemical derivatization and two-dimensional GC with time of flight MS (GCxGC/TOF-MS) was examined in this study for its efficacy in: 1) quantifying a high percentage of the total organic carbon (TOC) mass of a sample containing PO-OPM; 2) quantitatively determining PO-OPM components including carboxylic acids at atmospherically relevant concentrations; and 3) tentatively identifying PO-OPM components. Two derivatization reagent systems were used in this study: BF3/butanol for the butylation of carboxylic acids, aldehydes, and acidic ketones, and BSTFA for the trimethylsilylation (TMS) of carboxylic acids and alcohols. Three alpha-pinene ozonolysis OPM filter samples and a set of background filter samples were collected by collaborators in a University of California, Riverside environmental chamber. Derivatization/GCxGC TOF-MS was used to tentatively identify some previously unidentified ?-pinene ozonolysis products, and also to show the characteristics of all oxidation products determined. Derivatization efficiencies as measured were 40-70% for most butyl derivatives, and 50-58% for most trimethylsilyl derivatives. A thermal optical method was used to measure the TOC on each filter, and a value of the quantifiable TOC mass using a gas chromatograph was calculated for each sample using GCxGC separation and the mass-sensitive response of a flame ionization detector (FID). The TOC quantified using TMS and GCxGC-FID (TMS/TOCGCxGC FID) accounted for 15-23% of the TOC measured by the thermal-optical method. Using TMS and GCxGC/TOF-MS, 8.85% of the thermal optical TOC was measured and 48.2% of the TMS/TOCGCxGC-FID was semi-quantified using a surrogate standard. The carboxylic acids tentatively identified using TMS and GCxGC/TOF-MS accounted for 8.28% of the TOC measured by thermal optical means. GCxGC TOF-MS chromatograms of derivatized analytes showed reduced peak tailing due in part to the lesser interactions of the derivatized analytes with the stationary phase of the chromatography column as compared to the chromatograms of underivatized samples. The improved peak shape made possible the greater separation, quantification, and identification of high polarity analytes. Limits of detection using derivatization and GCxGC/TOF-MS were <1 ng per ?L injected for a series of C2-C6 di-acids, cis-pinonic acid, and dodecanoic acid using both butylation and TMS. Derivatization with GCxGC/TOF-MS was therefore effective for determining polar oxygenated compounds at low concentrations, for determining specific oxidation products not previously identified in OPM, and also for characterizing the probable functional groups and structures of ?-pinene ozonolysis products.

Boris, Alexandra Jeanne

371

Phosphopeptide quantitation using amine-reactive isobaric tagging reagents and tandem mass spectrometry: application to proteins isolated by gel electrophoresis.  

PubMed

Polyacrylamide gel electrophoresis is widely used for protein separation and it is frequently the final step in protein purification in biochemistry and proteomics. Using a commercially available amine-reactive isobaric tagging reagent (iTRAQ) and mass spectrometry we obtained reproducible, quantitative data from peptides derived by tryptic in-gel digestion of proteins and phosphoproteins. The protocol combines optimized reaction conditions, miniaturized peptide handling techniques and tandem mass spectrometry to quantify low- to sub-picomole amounts of (phospho)proteins that were isolated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Immobilized metal affinity chromatography (FeIII-IMAC) was efficient for removal of excess reagents and for enrichment of derivatized phosphopeptides prior to matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis. Phosphopeptide abundance was determined by liquid chromatography/tandem mass (LC/MS/MS) using either MALDI time-of-flight/time-of-flight (TOF/TOF) MS/MS or electrospray ionization quadrupole time-of-flight (ESI-QTOF) MS/MS instruments. Chemically labeled isobaric phosphopeptides, differing only by the position of the phosphate group, were distinguished and characterized by LC/MS/MS based on their LC elution profile and distinct MS/MS spectra. We expect this quantitative mass spectrometry method to be suitable for systematic, comparative analysis of molecular variants of proteins isolated by gel electrophoresis. PMID:16521170

Sachon, E; Mohammed, S; Bache, N; Jensen, O N

2006-01-01

372

Arsenic-containing fatty acids and hydrocarbons in marine oils - determination using reversed-phase HPLC-ICP-MS and HPLC-qTOF-MS.  

PubMed

Arsenolipids are the major arsenic species present in marine oils. Several structures of arsenolipids have been elucidated the last 5 years, demonstrating the chemical complexity of this trace element in the marine environment. Several commercial fish oils and marine oils, ranging in total arsenic concentrations from 1.6 to 12.5 mg kg(-1) oil, were analyzed for arsenolipids using reversed-phase high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The arsenolipids were quantified using three different arsenic-containing calibration standards; dimethylarsinate (DMA), triphenylarsinoxide (Ph?AsO) an