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1

Microbial Fingerprinting using Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS)  

Microsoft Academic Search

Recent threats posed by pathogenic microorganisms in food, recreational waters, and as agents of bioterror have underscored the need for the development of more rapid, accurate, and cost-effective methods of microbial characterization and identification. This chapter focuses on the use of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) to rapidly characterize and identify microorganisms through generation of characteristic

R. Giebel; C. Worden; S. M. Rust; G. T. Kleinheinz; M. Robbins; T. R. Sandrin

2010-01-01

2

Limits for the detection of (poly-)phosphoinositides by matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS)  

Microsoft Academic Search

Matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been recently established as a powerful tool for the analysis of biomolecules. Here, MALDI-TOF MS was used for the detection of (poly-)phosphoinositides (PPI). PPI possess higher molecular weights than other phospholipids and a high phosphorylation-dependent negative charge. Both features affect the MALDI detection limits expressed as the minimum of

Matthias Müller; Jürgen Schiller; Marijana Petkovi?; Wolf Oehrl; Regina Heinze; Reinhard Wetzker; Klaus Arnold; Jürgen Arnhold

2001-01-01

3

[Performance of two matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) models for identification of bacteria isolated from blood culture].  

PubMed

We compared the results of two bacterial identification methods: 1) a traditional method based on phenotypic identification of the causative organism using gram-staining, culture and biochemical markers and 2) matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A total of 111 isolates, including 107 strains of common bacteria species and 4 strains of 3 yeast species, were tested by the traditional method and MALDI-TOF MS method(VITEK MS and Micro flex LT). Data obtained using MALDI-TOF MS were classified as Level 1 and Level 2 according to the confidence level of identification results from the VITEK MS ver. 1.0 database (VITEK MS) and MALDI Biotyper ver. 2.0 database (Microflex LT). The proportions of measured samples identified as Level 1 were 98.2% with the VITEK MS database and 87.4% with the MALDI Biotyper database. The concordance rates of the traditional method were 93.7% with the VITEK MS database and 82.0% with the MALDI Biotyper database. Identification results of five strains were mismatched between the traditional method and MALDI-TOF MS. Their ribosomal RNA sequences were identical to the results obtained from MALDI-TOF MS. We concluded that the performance of VITEK MS is superior to that of the traditional method and Microflex LT. PMID:23947175

Itoh, Eisuke; Watari, Tomohisa; Azuma, Yuka; Watanabe, Naoki; Tomoda, Yutaka; Akasaka, Kazumi; Kino, Shuichi

2013-05-01

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

Optimization of matrix assisted desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) for the characterization of Bacillus and Brevibacillus species  

PubMed Central

Over the past few decades there has been an increased interest in using various analytical techniques for detecting and identifying microorganisms. More recently there has been an explosion in the application of matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) for bacterial characterization, and here we optimize this approach in order to generate reproducible MS data from bacteria belonging to the genera Bacillus and Brevibacillus. Unfortunately MALDI-TOF-MS generates large amounts of data and is prone to instrumental drift. To overcome these challenges we have developed a preprocessing pipeline that includes baseline correction, peak alignment followed by peak picking that in combination significantly reduces the dimensionality of the MS spectra and corrects for instrument drift. Following this two different prediction models were used which are based on support vector machines and these generated satisfactory prediction accuracies of approximately 90%. PMID:25086893

AlMasoud, Najla; Xu, Yun; Nicolaou, Nicoletta; Goodacre, Royston

2014-01-01

7

Optimization of matrix assisted desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) for the characterization of Bacillus and Brevibacillus species.  

PubMed

Over the past few decades there has been an increased interest in using various analytical techniques for detecting and identifying microorganisms. More recently there has been an explosion in the application of matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) for bacterial characterization, and here we optimize this approach in order to generate reproducible MS data from bacteria belonging to the genera Bacillus and Brevibacillus. Unfortunately MALDI-TOF-MS generates large amounts of data and is prone to instrumental drift. To overcome these challenges we have developed a preprocessing pipeline that includes baseline correction, peak alignment followed by peak picking that in combination significantly reduces the dimensionality of the MS spectra and corrects for instrument drift. Following this two different prediction models were used which are based on support vector machines and these generated satisfactory prediction accuracies of approximately 90%. PMID:25086893

AlMasoud, Najla; Xu, Yun; Nicolaou, Nicoletta; Goodacre, Royston

2014-08-20

8

Differences in protein profiles of the isolates of Entamoeba histolytica and E. dispar by surface-enhanced laser desorption ionization time-of-flight mass spectrometry (SELDI-TOF MS) ProteinChip assays  

Microsoft Academic Search

Surface-enhanced laser desorption ionization time of flight mass spectrometry (SELDI-TOF MS) ProteinChip assays with weak\\u000a cationic exchange chips were used for protein profiling of different isolates of Entamoeba histolytica and E. dispar. When SELDI-TOF MS spectra of cell lysates from E. histolytica strain HM-1:IMSS were compared with those from four other laboratory strains (200:NIH, HK-9, DKB, and SAW755CR) grown under

Asao Makioka; Masahiro Kumagai; Seiki Kobayashi; Tsutomu Takeuchi

2007-01-01

9

A direct and simple method of coupling matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) to thin-layer chromatography (TLC) for the analysis of phospholipids from egg yolk  

Microsoft Academic Search

Although the most important application of matrix-assisted laser desorption and ionization time-of-flight mass spectrometry\\u000a (MALDI-TOF MS) is “proteomics,” there is growing evidence that this soft ionization method is also useful for phospholipid\\u000a (PL) analysis. Although all PLs are detectable by MALDI-TOF MS, some lipid classes, particularly those with quaternary amines\\u000a such as phosphatidylcholines (PCs), are more sensitively detected than others,

Beate Fuchs; Jürgen Schiller; Rosmarie Süß; Martin Schürenberg; Detlev Suckau

2007-01-01

10

Gram-Stain Plus MALDI-TOF MS (Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry) for a Rapid Diagnosis of Urinary Tract Infection  

PubMed Central

Microbiological confirmation of a urinary tract infection (UTI) takes 24–48 h. In the meantime, patients are usually given empirical antibiotics, sometimes inappropriately. We assessed the feasibility of sequentially performing a Gram stain and MALDI-TOF MS mass spectrometry (MS) on urine samples to anticipate clinically useful information. In May-June 2012, we randomly selected 1000 urine samples from patients with suspected UTI. All were Gram stained and those yielding bacteria of a single morphotype were processed for MALDI-TOF MS. Our sequential algorithm was correlated with the standard semiquantitative urine culture result as follows: Match, the information provided was anticipative of culture result; Minor error, the information provided was partially anticipative of culture result; Major error, the information provided was incorrect, potentially leading to inappropriate changes in antimicrobial therapy. A positive culture was obtained in 242/1000 samples. The Gram stain revealed a single morphotype in 207 samples, which were subjected to MALDI-TOF MS. The diagnostic performance of the Gram stain was: sensitivity (Se) 81.3%, specificity (Sp) 93.2%, positive predictive value (PPV) 81.3%, negative predictive value (NPV) 93.2%, positive likelihood ratio (+LR) 11.91, negative likelihood ratio (?LR) 0.20 and accuracy 90.0% while that of MALDI-TOF MS was: Se 79.2%, Sp 73.5, +LR 2.99, ?LR 0.28 and accuracy 78.3%. The use of both techniques provided information anticipative of the culture result in 82.7% of cases, information with minor errors in 13.4% and information with major errors in 3.9%. Results were available within 1 h. Our serial algorithm provided information that was consistent or showed minor errors for 96.1% of urine samples from patients with suspected UTI. The clinical impacts of this rapid UTI diagnosis strategy need to be assessed through indicators of adequacy of treatment such as a reduced time to appropriate empirical treatment or earlier withdrawal of unnecessary antibiotics. PMID:24466289

Burillo, Almudena; Rodriguez-Sanchez, Belen; Ramiro, Ana; Cercenado, Emilia; Rodriguez-Creixems, Marta; Bouza, Emilio

2014-01-01

11

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

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 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

13

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

Microsoft Academic Search

The use of negative ion monitoring mode with an atmospheric pressure ion mobility orthogonal reflector time-of-flight mass\\u000a spectrometer [IM(tof)MS] to detect chemical warfare agent (CWA) degradation products from aqueous phase samples has been determined.\\u000a Aqueous phase sampling used a traditional electrospray ionization (ESI) source for sample introduction and ionization. Certified\\u000a reference materials (CRM) of CWA degradation products for the detection

Wes E. Steiner; Charles S. Harden; Feng Hong; Steve J. Klopsch; Vincent M. McHugh

2006-01-01

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

Rapid Discrimination of Haemophilus influenzae, H. parainfluenzae, and H. haemolyticus by Fluorescence In Situ Hybridization (FISH) and Two Matrix-Assisted Laser-Desorption-Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) Platforms  

PubMed Central

Background Due to considerable differences in pathogenicity, Haemophilus influenzae, H. parainfluenzae and H. haemolyticus have to be reliably discriminated in routine diagnostics. Retrospective analyses suggest frequent misidentifications of commensal H. haemolyticus as H. influenzae. In a multi-center approach, we assessed the suitability of fluorescence in situ hybridization (FISH) and matrix-assisted laser-desorption-ionization time-of-flight mass-spectrometry (MALDI-TOF-MS) for the identification of H. influenzae, H. parainfluenzae and H. haemolyticus to species level. Methodology A strain collection of 84 Haemophilus spp. comprising 50 H. influenzae, 25 H. parainfluenzae, 7 H. haemolyticus, and 2 H. parahaemolyticus including 77 clinical isolates was analyzed by FISH with newly designed DNA probes, and two different MALDI-TOF-MS systems (Bruker, Shimadzu) with and without prior formic acid extraction. Principal Findings Among the 84 Haemophilus strains analyzed, FISH led to 71 correct results (85%), 13 uninterpretable results (15%), and no misidentifications. Shimadzu MALDI-TOF-MS resulted in 59 correct identifications (70%), 19 uninterpretable results (23%), and 6 misidentifications (7%), using colony material applied directly. Bruker MALDI-TOF-MS with prior formic acid extraction led to 74 correct results (88%), 4 uninterpretable results (5%) and 6 misidentifications (7%). The Bruker MALDI-TOF-MS misidentifications could be resolved by the addition of a suitable H. haemolyticus reference spectrum to the system's database. In conclusion, no analyzed diagnostic procedure was free of errors. Diagnostic results have to be interpreted carefully and alternative tests should be applied in case of ambiguous test results on isolates from seriously ill patients. PMID:23646201

Frickmann, Hagen; Christner, Martin; Donat, Martina; Berger, Anja; Essig, Andreas; Podbielski, Andreas; Hagen, Ralf Matthias; Poppert, Sven

2013-01-01

16

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

17

Discrimination and characterization of environmental strains of Escherichia coli by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS).  

PubMed

A rapid and reliable bacterial source tracking (BST) method is essential to counter risks to human health posed by fecal contamination of surface waters. Genetic fingerprinting methods, such as repetitive sequence based-PCR (rep-PCR), have shown promise as BST tools but are time-consuming and labor-intensive. In this work, we investigate the ability of MALDI-TOF-MS to characterize and discriminate between closely related environmental strains of Escherichia coli and to classify them according to their respective sources. We compared the performance of a rapid MALDI-TOF-MS-based method to a commonly used rep-PCR-based method that employs the BOX-A1R primer. Among the criteria evaluated were repeatability and the ability of each method to group E. coli isolates according to their respective sources. Our data suggest that the MALDI-TOF-MS-based approach has a lower repeatability level compared to rep-PCR but offers an improved ability to correctly assign E. coli isolates to specific source groups. In addition, we have identified five biomarkers that appear conserved among avian species. We conclude that MALDI-TOF-MS may represent a promising, novel and rapid approach to addressing the problem of fecal contamination of surface waters and warrants further investigation. PMID:17184860

Siegrist, Thomas J; Anderson, Phillip D; Huen, Wing H; Kleinheinz, Gregory T; McDermott, Colleen M; Sandrin, Todd R

2007-03-01

18

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

19

Surface-enhanced laser desorption ionization time-of-flight mass spectrometry (SELDI TOF-MS) and ProteinChip ® technology in proteomics research  

Microsoft Academic Search

In this review article, we describe some of the studies that have been performed using the surface-enhanced laser desorption ionization (SELDI) time-of-flight mass spectrometry and ProteinChip® technology over the past few years, and highlight both their findings as well as limitations. Proteomic applications, such as target or marker identification and target validation or toxicology, will be addressed. We will also

Volker Seibert; Andreas Wiesner; Thomas Buschmann; Jörn Meuer

2004-01-01

20

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

21

A Silicon Nanomembrane Detector for Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) of Large Proteins  

PubMed Central

We describe a MALDI-TOF ion detector based on freestanding silicon nanomembrane technology. The detector is tested in a commercial MALDI-TOF mass spectrometer with equimolar mixtures of proteins. The operating principle of the nanomembrane detector is based on phonon-assisted field emission from these silicon nanomembranes, in which impinging ion packets excite electrons in the nanomembrane to higher energy states. Thereby the electrons can overcome the vacuum barrier and escape from the surface of the nanomembrane via field emission. Ion detection is demonstrated of apomyoglobin (16,952 Da), aldolase (39,212 Da), bovine serum albumin (66,430 Da), and their equimolar mixtures. In addition to the three intact ions, a large number of fragment ions are also revealed by the silicon nanomembrane detector, which are not observable with conventional detectors. PMID:24152929

Park, Jonghoo; Blick, Robert H.

2013-01-01

22

Accelerator-Based Surface Chemistry by Combined Time-of-Flight Mass Spectrometry (TOF-MS) and Particle-Induced X-Ray Emission (PIXE)  

SciTech Connect

We describe the development of a new capability for performing microscopic chemical analysis in the near surface of a sample. The technology uses a focused high-energy ion beam from an accelerator to cause characteristic elemental x-rays to be emitted and, simultaneously, molecules and fragments to be desorbed from the surface of the sample. Spectroscopic analysis of the fluoresced x-rays provides quantitative trace element information of the sample volume probed by the beam. The elemental data are subsequently used to identify peaks in the mass analysis of the desorbed species, thereby providing a detailed description of the local surface chemistry. High-resolution (micron-scale) chemical imaging is possible by scanning the beam over the sample.

Morse, D H; Grant, P G; Antolak, A J; Sproch, N; Fernando, Q

2002-05-31

23

Measuring the mass of an electron by LC/TOF-MS: a study of "twin ions".  

PubMed

While investigating the in-source CID fragmentation of nonsteroidal antiinflammatory drugs (NSAIDs), it was noticed that the same fragment ion (nominal mass) formed in either positive or negative ion electrospray for a suite of NSAIDs. For example, ibuprofen with a molecular mass of 206, fragments to the m/z 161 ion in negative ion from its deprotonated molecule (m/z 205, [M - H]-) and fragments to the m/z 161 ion in positive ion from its protonated molecule (m/z 207, [M + H]+). This fragment ion was euphemistically called a "twin ion"because of the same nominal mass despite opposite charge. The CID fragmentation of the twin ions was confirmed also by LC/MS/MS ion trap. Accurate mass measurements in negative ion show that the loss was due to CO2 (measured loss of 43.9897 atomic mass units (u) versus calculated loss of 43.9898 u for N = 10) and in positive ion the loss is due to HCOOH (measured loss of 46.0048 u versus calculated loss of 46.0055 u, N = 10). It was realized that, in fact, the ions were not "identical mass twins of opposite charge" but separated in accurate mass by two electrons. The accurate mass measurement by liquid chromatography/time-of-flight-mass spectrometry (LC/TOF-MS) can distinguish between the two fragment ions of ibuprofen (161.13362 +/- 0.00019 and 161.13243 +/- 0.00014 for N = 20). This experiment was repeated for two other NSAIDs, and the mass of an electron was measured as the difference between the twin ions, which was 0.00062 u +/- 14.8% relative standard deviation (N = 20 analyses). Thus, the use of continuous calibration makes it possible to measure the mass of an electron within one significant figure using the NSAID solution. This result shows the importance of including electron mass in accurate mass measurements and the value of a benchmark test for LC/TOF-MS mass accuracy. PMID:15889935

Ferrer, Imma; Thurman, E Michael

2005-05-15

24

[Metabolite fingerprint and biomarkers identification of rat urine after dosed with ginsenoside Rg3 based on ultra high performance liquid chromatography/time-of-flight mass spectrometry (UPLC/TOF-MS)].  

PubMed

Porous particles of 1.7 microm was employed for ultra high performance liquid chromatography (UPLC), resulting in higher peak capacity, greater resolution and increased sensitivity in comparison with high performance liquid chromatography (HPLC). Time-of-flight mass spectrometer (TOF-MS) with a lockmass interface was used for the structure identification through exact mass and MS/MS experiment. The hyphenation of these two technologies made it a suitable platform for analysis of complex samples and identification of unknown compounds. Ginsenoside Rg3 has been considered as the major active component of Panax ginseng. Effect of the administration of a single dose of the Ginsenoside Rg3 to male Sprague Dawley rats on the urinary metabolite profiles of a range of endogenous metabolites had been investigated using UPLC/TOF-MS. Urine samples were collected from both dosed and control animals. Analysis of these samples revealed marked changes in the pattern of endogenous metabolites due to the effect of Ginsenoside Rg3. Significant disturbances in the urinary metabolite were observed in the first day after dose. Endogenous metabolites with significant up-regulation identified by accurate mass and MS/MS were xanthurenic acid, and kynurenic acid. PMID:16827300

Wang, Jiangshan; Zhao, Xinjie; Zheng, Yufang; Kong, Hongwei; Lu, Guo; Cai, Zongwei; Xu, Guowang

2006-01-01

25

The identification of anaerobic bacteria using MALDI-TOF MS  

Microsoft Academic Search

Matrix Assisted Laser Desorption and Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) has gained more and more popularity for the identification of bacteria. Several studies show that bacterial diagnosticis is being revolutionized by the application of MALDI-TOF MS. For anaerobic bacteria, MALDI-TOF MS has been used for the identification of Prevotella spp., Fusobacterium spp., Clostridium spp., Bacteroides spp. and Gram-positive anaerobic

A. C. M. Veloo; G. W. Welling; J. E. Degener

2011-01-01

26

Genetic and Ecological Correlates of Intraspecific Variation in Pitviper Venom Composition Detected Using Matrix-Assisted Laser Desorption Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) and Isoelectric Focusing  

Microsoft Academic Search

The ability to detect biochemical diversity in animal venoms has wide-ranging implications for a diverse array of scientific disciplines. Matrix-assisted laser desorption time-of-flight mass spectrometry (and, for comparative purposes, isoelectric focusing) were used to characterize venoms from a geographically diverse sample of Trimeresurus stejnegeri (n 2 isoforms (PLA2) and in whole venom profiles. Geographic variation in venom was primarily between

Simon Creer; Anita Malhotra; Roger S. Thorpe; Reto S. Stöcklin; Philippe S. Favreau; Wen S. Hao Chou

2003-01-01

27

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

28

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

29

The SELDI-TOF MS Approach to Proteomics: Protein Profiling and Biomarker Identification  

Microsoft Academic Search

The need for methods to identify disease biomarkers is underscored by the survival-rate of patients diagnosed at early stages of cancer progression. Surface enhanced laser desorption\\/ionization time-of-flight mass spectrometry (SELDI-TOF MS) is a novel approach to biomarker discovery that combines two powerful techniques: chromatography and mass spectrometry. One of the key features of SELDI-TOF MS is its ability to provide

Haleem J. Issaq; Timothy D. Veenstra; Thomas P. Conrads; Donna Felschow

2002-01-01

30

Investigating the human metabolism of acetaminophen using UPLC and exact mass oa-TOF MS  

Microsoft Academic Search

The ability to rapidly detect and characterize drug metabolites in biological fluids often relies on a combination of a high quality chromatographic separation and sensitive high resolution mass spectrometry. Here, the performance of two high throughput LC\\/MS approaches, namely monolith columns and sub-2?m particle Ultra Performance Liquid Chromatography (UPLC) columns is compared for the detection and identification of the human

Kelly A. Johnson; Robert Plumb

2005-01-01

31

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

32

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

33

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

34

Comparative study of MALDI-TOF MS and VITEK 2 in bacteria identification  

PubMed Central

Background Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently been introduced in diagnostic microbiology laboratories for the identification of bacterial and yeast strains isolated from clinical samples. This study aimed to evaluate the accuracy of MALDI-TOF MS in clinical microbiology diagnosis by comparing it with commonly-used VITEK 2 or gene sequencing. Methods The performances of MALDI-TOF MS and VITEK 2 were compared retrospectively for identifying routine isolates. Discrepancies were analyzed by gene sequencing analysis of the 16S genes. Results For 1,025 isolates, classified as 55 species of 25 genera, 1,021 (99.60%) isolates were accurately identified at the genus level, and 957 (93.37%) isolates at the species level by using MALDI-TOF MS. A total of 949 (92.59%) isolates were completely matched by both methods. Both methods found 76 unmatched isolates among which one strain had no definite identification by MALDI-TOF MS and VITEK 2 respectively. However, MALDI-TOF MS made no errors at the genus level while VITEK 2 made 6 (0.58%) errors at the genus level. At the species level, the identification error rates for MALDI-TOF MS and VITEK 2 were 5.56% and 6.24%, respectively. Conclusions With a lower identification error rate, MALDI-TOF MS has better performance than VITEK 2 in identifying bacteria found routinely in the clinical laboratory. It is a quick and cost-effective technique, and has the potential to replace conventional phenotype methods in identifying common bacterial isolates in clinical microbiology laboratories. PMID:24822115

Guo, Ling; Ye, Liyan; Zhao, Qiang; Ma, Yanning; Yang, Jiyong

2014-01-01

35

Matrix-assisted laser desorption\\/ionization time-of-flight mass spectrometry in clinical chemistry  

Microsoft Academic Search

Matrix-assisted laser desorption\\/ionization time-of-flight mass spectrometry (MALDI-Tof-MS) has recently become a popular and versatile method to analyze macromolecules from biological origin. In this paper, we will review the application of MALDI-Tof-MS in clinical chemistry and biology. MALDI-Tof-MS is used in clinical chemistry, e.g. disease markers can be identified with MALDI-MS analysis in combination with 1-D and 2-D gel electrophoresis separations

Laure F. Marvin; Matthew A. Roberts; Laurent B. Fay

2003-01-01

36

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

37

Identification of CMY-2-Type Cephalosporinases in Clinical Isolates of Enterobacteriaceae by MALDI-TOF MS  

PubMed Central

This study exploited the possibility to detect Citrobacter freundii-derived CMY-2-like cephalosporinases in Enterobacteriaceae clinical isolates using matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). Periplasmic proteins were prepared using a modified sucrose method and analyzed by MALDI-TOF MS. A ca. 39,850-m/z peak, confirmed to represent a C. freundii-like ?-lactamase by in-gel tryptic digestion followed by MALDI-TOF/TOF MS, was observed only in CMY-producing isolates. We have also shown the potential of the assay to detect ACC- and DHA-like AmpC-type ?-lactamases. PMID:24566177

Papagiannitsis, C. C.; Kotsakis, S. D.; Tuma, Z.; Gniadkowski, M.; Miriagou, V.

2014-01-01

38

Protein quantification by the SELDI-TOF-MS–based ProteinChip® System  

Microsoft Academic Search

Surface-enhanced laser desorption\\/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) represents the successful combination of retentate chromatography and mass spectrometry, and this technology is an integral part of Ciphergen's ProteinChip System, which was designed to answer biomedical questions by performing protein analyses on a single experimental platform. The quantification capability of the ProteinChip System is essential in all proteomic applications for which this

Sonja Vorderwülbecke; Steve Cleverley; Scot R Weinberger; Andreas Wiesner

2005-01-01

39

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

40

[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

41

Improved ionization sources and detection methods for analytical mass spectrometry  

SciTech Connect

A new time-of-flight mass spectrometer (TOF-MS) has been developed for direct characterization of solid samples and fundamental studies. A N{sub 2} laser ({lambda} = 337 nm) was used with the linear TOF-MS to study ion formation from various solid specimens. Improved techniques were incorporated for fast ion detection and data acquisition. For inorganic specimens the mass resolution was {approximately} 2000 at m/z = 400, a considerable improvement over earlier reports for instruments using a linear ion optical path. The TOF-MS was designed specifically to permit investigation of the information available from the individual TOF scans. The approach is described and results are given for the LD-TOF-MS spectra of CsI and a superconducting sample, YBa{sub 2}Cu{sub 3}O{sub 7}. Other improvements in laser excitation of specimens and detection methods for analytical mass spectrometry are also described.

Huang, L.Q.

1987-01-01

42

Rapid discrimination of Legionella by matrix-assisted laser desorption ionization time-of-flight mass spectrometry.  

PubMed

Molecular typing is an important tool in the surveillance and investigation of human Legionella infection outbreaks. In this study, two molecular typing methods, pulsed-field gel electrophoresis (PFGE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), were used to discriminate 23 Legionella pneumophila strains. The usefulness of MALDI-TOF-MS was demonstrated. The MALDI-TOF-MS fingerprinting with filtered small acid-soluble molecules gave different molecular profiles among strains, and the clustal analysis with MALDI-TOF-MS showed a high discrimination of strains the same as that with PFGE. In addition, MALDI-TOF-MS data could be generated within a few hours after the initial culture, although PFGE analyses took several days to complete. Thus, MALDI-TOF-MS offers a simple and rapid discrimination technique that could aid in the tracking of fast-spreading outbreaks of Legionella. PMID:20347283

Fujinami, Yoshihito; Kikkawa, Hitomi S; Kurosaki, Yohei; Sakurada, Koichi; Yoshino, Mineo; Yasuda, Jiro

2011-02-20

43

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

44

Optimization of MALDI-TOF MS for strain level differentiation of Arthrobacter isolates  

Microsoft Academic Search

Matrix-assisted laser-desorption\\/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been shown to be a rapid and sensitive method for characterization of bacteria, but it has not yet become a routine microbiological procedure. Currently there are no standardized protocols that would allow development of large libraries of reproducible protein profiles from a broad range of microorganisms to use for identification purposes. Important

Márta Vargha; Zoltán Takáts; Allan Konopka; Cindy H. Nakatsu

2006-01-01

45

A Plant Peptide Encoded by CLV3 Identified by in Situ MALDI-TOF MS Analysis  

Microsoft Academic Search

The Arabidopsis CLAVATA3 (CLV3) gene encodes a stem cell-specific protein presumed to be a precursor of a secreted peptide hormone. Matrix-assisted laser desorption\\/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) applied to in situ Arabidopsis tissues determined the structure of a modified 12-amino acid peptide (MCLV3), which was derived from a conserved motif in the CLV3 sequence. Synthetic MCLV3 induced shoot and root

Tatsuhiko Kondo; Shinichiro Sawa; Atsuko Kinoshita; Satoko Mizuno; Tatsuo Kakimoto; Hiroo Fukuda; Youji Sakagami

2006-01-01

46

Using oxidized carbon nanotubes as matrix for analysis of small molecules by MALDI-TOF MS  

Microsoft Academic Search

Oxidized carbon nanotubes are tested as a matrix for analysis of small molecules by matrix assisted laser desorption\\/ionization\\u000a time of flight mass spectrometry (MALDI-TOF-MS). Compared with nonoxidized carbon nanotubes, oxidized carbon nanotubes facilitate\\u000a sample preparation because of their higher solubility in water. The matrix layer of oxidized carbon nanotubes is much more\\u000a homogeneous and compact than that of nonoxidized carbon

Chensong Pan; Songyun Xu; Ligang Hu; Xingye Su; Junjie Ou; Hanfa Zou; Zhong Guo; Yu Zhang; Baochuan Guo

2005-01-01

47

SELDI-TOF-MS of saliva: Methodology and pre-treatment effects  

Microsoft Academic Search

Interest in saliva as a diagnostic fluid for monitoring general health and for early diagnosis of disease has increased in the last few years. In particular, efforts have focused on the generation of protein maps of saliva using advanced proteomics technology. Surface-enhanced laser-desorption\\/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) is a novel high throughput and extremely sensitive proteomic approach that allows protein

Raymond Schipper; Arnoud Loof; Jolan de Groot; Lucien Harthoorn; Eric Dransfield; Waander van Heerde

2007-01-01

48

Comparative evaluation of software for deconvolution of metabolomics data based on GC-TOF-MS  

Microsoft Academic Search

Traditional options available for deconvolution of data from gas chromatography-mass spectrometry (GC-MS) experiments have mostly been confined to semi-automated methods, which cannot compete with high-throughput and rapid analysis in metabolomics. In the present study, data sets acquired using GC with time-of-flight MS (GC-TOF-MS) were processed using three different deconvolution software packages (LECO ChromaTOF, AMDIS and SpectralWorks AnalyzerPro).We paid attention to

Warwick B. Dunn; Hailin Shen; Douglas B. Kell

2008-01-01

49

Performance of Two Resin-Containing Blood Culture Media in Detection of Bloodstream Infections and in Direct Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) Broth Assays for Isolate Identification: Clinical Comparison of the BacT/Alert Plus and Bactec Plus Systems.  

PubMed

We compared the clinical performances of the BacT/Alert Plus (bioMérieux) and Bactec Plus (Becton Dickinson) aerobic and anaerobic blood culture (BC) media with adsorbent polymeric beads. Patients ?16 years old with suspected bloodstream infections (BSIs) were enrolled in intensive care units and infectious disease wards. A single 40-ml blood sample was collected from each and used to inoculate (10 ml/bottle) one set of BacT/Alert Plus cultures and one set of Bactec Plus cultures, each set consisting of one aerobic and one anaerobic bottle. Cultures were incubated ?5 days in the BacT/Alert 3D and Bactec FX instruments, respectively. A total of 128 unique BSI episodes were identified based on the recovery of clinically significant growth in 212 aerobic cultures (106 BacT/Alert and 106 Bactec) and 151 anaerobic cultures (82 BacT/Alert and 69 Bactec). The BacT/Alert aerobic medium had higher recovery rates for Gram-positive cocci (P = 0.024), whereas the Bactec aerobic medium was superior for recovery of Gram-negative bacilli (P = 0.006). BacT/Alert anaerobic medium recovery rates exceeded those of the Bactec anaerobic medium for total organisms (P = 0.003), Gram-positive cocci (P = 0.013), and Escherichia coli (P = 0.030). In terms of capacity for diagnosing the 128 septic episodes, the BacT/Alert and Bactec sets were comparable, although the former sets diagnosed more BSIs caused by Gram-positive cocci (P = 0.008). They also allowed earlier identification of coagulase-negative staphylococcal growth (mean, 2.8 h; P = 0.003) and growth in samples from patients not on antimicrobial therapy that yielded positive results (mean, 1.3 h; P < 0.001). Similarly high percentages of microorganisms in BacT/Alert and Bactec cultures (93.8% and 93.3%, respectively) were identified by direct matrix-assisted laser desorption ionization-time of flight mass spectrometry assay of BC broths. The BacT/Alert Plus media line appears to be a reliable, timesaving tool for routine detection of BSIs in the population we studied, although further studies are needed to evaluate their performance in other settings. PMID:25031441

Fiori, Barbara; D'Inzeo, Tiziana; Di Florio, Viviana; De Maio, Flavio; De Angelis, Giulia; Giaquinto, Alessia; Campana, Lara; Tanzarella, Eloisa; Tumbarello, Mario; Antonelli, Massimo; Sanguinetti, Maurizio; Spanu, Teresa

2014-10-01

50

The potential of combining ion trap/MS/MS and TOF/MS for identification of emerging contaminants  

USGS Publications Warehouse

The use of a method combining ion trap tandem mass spectrometry (MS/MS) and time of flight mass spectrometry (TOF/MS) for identification of emerging contaminates was discussed. The two tools together complemented each other in sensitivity, fragmentation and accurate mass determination. Liquid chromatography/electrospray ionization/ion-trap tandem mass spectrometry (LC/ESI/MS/MS), in positive ion mode of operation, was used to separate and identify specific compounds. Diagnostic fragment ions were obtained for a polyethyleneglycol(PEG) homolog by ion trap MS/MS, and fragments were measured by TOF/MS. It was observed that the combined method gave an exact mass measurement that differed from the calculated mass.

Ferrer, I.; Furlong, E. T.; Heine, C. E.; Thurman, E. M.

2002-01-01

51

Identification of Orcokinin Gene-Related Peptides in the Brain of the Crayfish Procambarus clarkii by the Combination of MALDI-TOF and On-Line Capillary HPLC\\/Q-Tof Mass Spectrometries and Molecular Cloning  

Microsoft Academic Search

We developed a strategy for the exploration of brain peptides in the red swamp crayfish, Procambarus clarkii, utilizing the combined techniques of matrix-assisted laser desorption\\/ionization with time-of-flight mass spectrometry (MALDI-TOF MS), molecular cloning, and on-line capillary reversed-phase HPLC\\/quadrupole orthogonal acceleration time-of-flight (Q-Tof)-MS. We initially performed direct MALDI-TOF MS analysis with slices of the brain. The MS spectra from a slice

Yoshimi Yasuda-Kamatani; Akikazu Yasuda

2000-01-01

52

Identification and quantitation of pesticides in vegetables by liquid chromatography time-of-flight mass spectrometry  

Microsoft Academic Search

This overview covers pesticide-residue determination in food samples by liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS). We present the application of LC-TOF-MS in terms of accuracy, sensitivity and robustness for the quantitative analysis of pesticides in fruit and vegetable samples. The analytical performance of the methodology is validated for various types of vegetables matrices.Accurate mass measurements (with accuracy better than 3ppm

Imma Ferrer; Juan Francisco García-Reyes; Amadeo Fernandez-Alba

2005-01-01

53

Matrix-assisted laser desorption\\/ionization time-of-flight mass spectrometry in clinical chemistry  

Microsoft Academic Search

Abstract Matrix-assisted laser desorption\\/ionization time-of-flight mass,spectrometry,(MALDI-Tof-MS) has recently become,a popular and versatile method to analyze macromolecules from biological origin. In this paper, we will review the application of MALDI-Tof-MS in clinical chemistry and biology. MALDI-Tof-MS is used in clinical chemistry, e.g. disease markers can be identified with MALDI-MS analysis in combination,with 1-D and 2-D gel electrophoresis separations thanks to either

Laure F. Marvin; Matthew A. Roberts; Laurent B. Fay

54

Analyses by UPLC Q-TOF MS of products of aflatoxin B(1) after ozone treatment.  

PubMed

Analysing the products of ozone-treated aflatoxin B1 (AFB1) is essential in order to study the practical use of ozone treatment. In this paper, the products of AFB1 were investigated using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC Q-TOF MS). The products were well separated using UPLC, and the accurate masses of all the products were determined using Q-TOF MS. Finally, the possible pathways of fragmentation ion generation from the products of AFB1 and the structures of four products were proposed. From the view of the proposed structures of products, the C8-C9 double bond in the terminal furan ring was destroyed. According to the structure-activity relationship, the toxicity of products was significantly reduced compared with that of AFB1. The result indicated that ozone was an effective agent for degrading AFB1, and UPLC Q-TOF MS was a useful analytical tool for proposing and identifying a series of unknown products. PMID:24350699

Luo, Xiaohu; Wang, Ren; Wang, Li; Li, Yongfu; Zheng, Ruihang; Sun, Xiulan; Wang, Yong; Chen, Zhengxing; Tao, Guanjun

2014-01-01

55

Recent developments in methods and technology for analysis of biological samples by MALDI-TOF-MS  

Microsoft Academic Search

Matrix-assisted laser desorption\\/ionization–time-of-flight mass spectrometry (MALDI-TOF-MS) is widely used in a variety of\\u000a fields because it has the characteristics of speed, ease of use, high sensitivity, and wide detectable mass range for obtaining\\u000a molecular weights and for structural characterization of macromolecules. In this article we summarize recent developments\\u000a in matrix additives, new matrices, and sample-pretreatment methods using off-probe or on-probe

Chensong Pan; Songyun Xu; Houjiang Zhou; Yu Fu; Mingliang Ye; Hanfa Zou

2007-01-01

56

A food safety control low mass-range proteomics platform for the detection of illicit treatments in veal calves by MALDI-TOF-MS serum profiling.  

PubMed

Performance enhancing agents (PEAs) are illegally used in cattle and other meat producing species to increase food conversion and lean meat production. Due to the very short breeding cycle, veal calves represent the meat producing bovine category mostly subjected to illicit treatments. These chemical agents are difficult to detect by conventional analytical approaches due to the employment of synergistic formulations at very low dosage and given the use of uncharacterized novel compounds. Such a scenario has fostered a strong interest in the discovery of functional molecular biomarkers for the detection of growth promoting agents in meat producing species. A multivariate MALDI-TOF-MS proteomics platform has been developed using bovine serum samples. Analytical performances have been thoroughly evaluated in order to enable reproducible profiles from 10 microL sera samples. We propose univariate and multivariate discrimination models capable to identify calves undergoing illicit treatments. In particular, we found a strong discrimination power associated with a polypeptide fragment from beta2-glycoprotein-I. We provide a fundamental proof of concept in the potential application of MALDI-TOF-MS proteomics profiling in the food safety control. PMID:19844911

Della Donna, Lorenza; Ronci, Maurizio; Sacchetta, Paolo; Di Ilio, Carmine; Biolatti, Bartolomeo; Federici, Giorgio; Nebbia, Carlo; Urbani, Andrea

2009-11-01

57

A Rapid MALDI-TOF MS Identification Database at Genospecies Level for Clinical and Environmental Aeromonas Strains  

PubMed Central

The genus Aeromonas has undergone a number of taxonomic and nomenclature revisions over the past 20 years, and new (sub)species and biogroups are continuously described. Standard identification methods such as biochemical characterization have deficiencies and do not allow clarification of the taxonomic position. This report describes the development of a matrix-assisted laser desorption/ionisation–time of flight mass spectrometry (MALDI-TOF MS) identification database for a rapid identification of clinical and environmental Aeromonas isolates. PMID:23119019

Benagli, Cinzia; Demarta, Antonella; Caminada, AnnaPaola; Ziegler, Dominik; Petrini, Orlando; Tonolla, Mauro

2012-01-01

58

MALDI-TOF MS of phosphatidylethanolamines: Different adducts cause different post source decay (PSD) fragment ion spectra  

Microsoft Academic Search

Matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) is increasingly applied to lipids. However, positional acyl chain analysis of lipids by MALDI was so far scarcely described.In this paper, the fragmentation behavior of phosphatidylethanolamine (PE) is investigated by using post-source decay (PSD) MS. In dependence on the investigated adduct, significant differences could be obtained. It will be shown

Beate Fuchs; Celestina Schober; Grit Richter; Rosmarie Süß; Jürgen Schiller

2007-01-01

59

Enhancement of charge remote fragmentation in protonated peptides by high-energy CID MALDI-TOF-MS using “cold” matrices  

Microsoft Academic Search

Delayed extraction matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (DE-MALDI-TOF-MS) is employed to evaluate its potential for peptide sequencing using both post-source decay (PSD) and high-energy collision-induced dissociation (CID). This work provides evidence that complete amino-acid sequences may be obtained employing a dual approach including PSD of [M + H]+ ions using a “hot” matrix (?-cyano-4-hydroxycinnamic acid, CHCA), followed by

E. Stimson; O. Truong; W. J. Richter; M. D. Waterfield; A. L. Burlingame

1997-01-01

60

Automated Gain Control Ion Funnel Trap for Orthogonal Time-of-Flight Mass Spectrometry  

SciTech Connect

Time-of-flight mass spectrometry (TOF MS) is increasingly used in proteomics research. Herein, we report on the development and characterization of an ultra-sensitive TOF MS instrument equipped with an electrodynamic ion funnel trap (IFT) that employs an automatic gain control (AGC) capability. The IFT-TOF MS was coupled to a reverse-phase capillary liquid chromatography (RPLC) separation and evaluated in experiments with complex proteolytic digests. When applied to a global tryptic digest of Shewanella oneidensis proteins, an order-of-magnitude increase in sensitivity compared to that of the conventional continuous mode of operation was achieved due to efficient ion accumulation prior to TOF MS analysis. As a result of this sensitivity improvement and related improvement in mass measurement accuracy, the number of unique peptides identified in the AGC-IFT mode was 5-fold greater than that obtained in the continuous mode.

Ibrahim, Yehia M.; Belov, Mikhail E.; Liyu, Andrei V.; Smith, Richard D.

2008-07-15

61

Use of MALDI-TOF MS technique for rapid identification of bacteria from positive blood cultures.  

PubMed

We evaluated the feasibility of same-day routine aerobic bacterial identification using the following procedures: Picking colonies from 4 and 6 h incubated subculture from positive blood culture bottle and analyzing them by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS). The matched identification rate of this procedure at the species level was 80.6% (141/175) for the 4-h cultures compared with overnight cultures and 90.9% (159/175) for the 6-h cultures. Thus, our technique provides an easy and rapid method for identification of aerobic bacteria in routine clinical microbiology laboratories. PMID:25297028

Hong, Sung Kuk; Chang, Beung Ki; Song, Sang Hoon; Kim, Eui-Chong

2014-01-01

62

Detection and quantification of bacterial spoilage in milk and pork meat using MALDI-TOF-MS and multivariate analysis.  

PubMed

Microbiological safety is one of the cornerstones of quality control in the food industry. Identification and quantification of spoilage bacteria in pasteurized milk and meat in the food industry currently relies on accurate and sensitive yet time-consuming techniques which give retrospective values for microbial contamination. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), a proven technique in the field of protein and peptide identification and quantification, may be a valuable alternative approach for the rapid assessment of microbial spoilage. In this work we therefore developed MALDI-TOF-MS as a novel analytical approach for the assessment of food that when combined with chemometrics allows for the detection and quantification of milk and pork meat spoilage bacteria. To develop this approach, natural spoilage of pasteurized milk and raw pork meat samples incubated at 15 °C and at room temperature, respectively, was conducted. Samples were collected for MALDI-TOF-MS analysis (which took 4 min per sample) at regular time intervals throughout the spoilage process, with concurrent calculation and documentation of reference total viable counts using traditional microbiological methods (these took 2 days). Multivariate statistical techniques such as principal component discriminant function analysis, canonical correlation analysis, partial least-squares (PLS) regression, and kernel PLS (KPLS) were used to analyze the data. The results from MALDI-TOF-MS combined with PLS or KPLS gave excellent bacterial quantification results for both milk and meat spoilage, and typical root mean squared errors for prediction in test spectra were between 0.53 and 0.79 log unit. Overall these novel findings strongly indicate that MALDI-TOF-MS when combined with chemometric approaches would be a useful adjunct for routine use in the milk and meat industry as a fast and accurate viable bacterial detection and quantification method. PMID:22698768

Nicolaou, Nicoletta; Xu, Yun; Goodacre, Royston

2012-07-17

63

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

64

Toward an In Situ Organic and Atomic Microprobe with Laser TOF-MS  

NASA Technical Reports Server (NTRS)

We present details of a new miniature laser time-of-flight mass spectrometer (TOF-MS) with improved resolution and sensitivity, for in situ analysis of elemental, isotopic, and organic/molecular composition.

Brinckerhoff, W. B.; Cornish, T. J.; McEntire, R. W.; Cheng, A. F.; Benson, R. C.

2000-01-01

65

Accurate mass measurements for the confirmation of Sudan azo-dyes in hot chilli products by capillary liquid chromatography–electrospray tandem quadrupole orthogonal-acceleration time of flight mass spectrometry  

Microsoft Academic Search

The potential of capillary liquid chromatography (microLC)–quadrupole\\/time-of-flight mass spectrometry (Q-TOF MS) for the confirmation of Sudan I, II, III and IV azo-dyes as contaminants in hot-chilli food products was demonstrated. Using the microLC–electrospray ionization (ESI)–Q-TOF MS technique, accurate mass measurements of Sudan dyes were performed both on standard solutions and on matrices. Precision of exact mass measurements was calculated taking

F. Calbiani; M. Careri; L. Elviri; A. Mangia; I. Zagnoni

2004-01-01

66

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

67

Rapid characterization of the fatty acyl composition of complex lipids by collision-induced dissociation time-of-flight mass spectrometry  

Microsoft Academic Search

Profiling of leaf extracts from mutants of Arabidopsis with defects in lipid desaturation demonstrates the utility of collision-induced dissociation time-of-flight mass spectrometry (CID-TOF MS) for screening biological samples for fatty acid compositional alterations. CID-TOF MS uses the collision cell of a quadrupole time-of-flight mass spectrometer to simultaneously fragment all of the ions produced by an ionization source. Electrospray ioni- zation

Steven Wynn Esch; Pamela Tamura; Alexis A. Sparks; Mary R. Roth; Shivakumar P. Devaiah; Ernst Heinz; Xuemin Wang; Todd D. Williams; Ruth Welti

2006-01-01

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

Identification of bio-active metabolites of gentiopicroside by UPLC/Q-TOF MS and NMR.  

PubMed

Gentiopicroside (GPS), the main bioactive component in Gentiana scabra Bge., has attracted our attention owing to its high bioactivity, especially the treatment of hepatobiliary disorders. The aglycone form of GPS, a typical secoiridoid glycoside, is considered to be more readily absorbed than its parent drug. This study aimed to identify and characterize the metabolites after GPS incubated with ?-glucosidase in buffer solution at 37°C. Samples of biotransformed solution were collected and analyzed by ultraperformance liquid chromatography (UPLC)/quadrupole-time-of-flight mass spectrometry (Q-TOF MS). A total of four metabolites were detected: two were isolated and elucidated by preparative-HPLC and NMR techniques, and one of those four is reported for the first time. The mass spectral fragmentation pattern and accurate masses of metabolites were established on the basis of UPLC/Q-TOF MS analysis. Structure elucidation of metabolites was achieved by comparing their fragmentation pattern with that of the parent drug. A fairly possible metabolic pathway of GPS by ?-glucosidase was proposed. The hepatoprotective activities of metabolites M1 and M2 were investigated and the results showed that their hepatoprotective activities were higher than that of parent drug. Our results provided a meaningful basis for discovering lead compounds from biotransformation related to G. scabra Bge. in traditional Chinese medicine. PMID:23733682

Zeng, Wenliang; Han, Han; Tao, Yanyan; Yang, Li; Wang, Zhengtao; Chen, Kaixian

2013-09-01

70

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

71

Phenotypic Detection of Carbapenemase-Producing Enterobacteriaceae by Use of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry and the Carba NP Test.  

PubMed

We compared the diagnostic accuracy of the Carba NP test with that of a straightforward matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) method for detecting carbapenemase-producing Enterobacteriaceae (CPE). Using PCR as the reference method, both tests demonstrated a sensitivity of 87% and a specificity of 100%. MALDI-TOF MS offers a potential alternative for the rapid detection of CPE in the clinical laboratory setting. PMID:25187633

Knox, James; Jadhav, Snehal; Sevior, Danielle; Agyekum, Alex; Whipp, Margaret; Waring, Lynette; Iredell, Jonathan; Palombo, Enzo

2014-11-01

72

Rapid Identification of Staphylococci Isolated in Clinical Microbiology Laboratories 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) of intact bacteria yields a reproducible spectrum depending upon growth conditions, strain, or species. Using whole viable bacteria we describe here the application of MALDI-TOF-MS to the identification of coag- ulase-negative staphylococci (CoNS). Our aim was, once a bacterium has been recognized as Micrococ- caceae, to identify peaks in the spectrum

Etienne Carbonnelle; Jean-Luc Beretti; Stephanie Cottyn; Gilles Quesne; Patrick Berche; Xavier Nassif; Agnes Ferroni; Hopital Necker-Enfants Malades

2007-01-01

73

Development of GCxGC/TOF-MS metabolomics for use in ecotoxicological studies with invertebrates.  

PubMed

The majority of metabolomic studies used in ecotoxicology have implemented (1)H NMR analysis. Despite constant improvement, major limitations of NMR-based techniques include relatively low sensitivity that results in an examination of a limited number of metabolites. An alternative approach is the use of liquid or gas chromatography (GC) for separation of metabolites and mass spectrometry (MS) for their quantification and identification. The objective of our study was to develop a two dimensional GC coupled with time of flight MS (GCxGC/TOF-MS) coupled with multivariate analysis to compare metabolite profiles of Diporeia under different environmental conditions. We compared metabolite profiles between Diporeia collected from Lake Michigan (declining populations) to those residing in Lake Superior (stable populations), and also between Diporeia exposed to a chemical stressor (atrazine) and controls. Overall, 76 and 302 total metabolites were detected from the lake comparison and atrazine studies, respectively. Many of the identified metabolites included fatty acids, amino acids, and hydrocarbons. Furthermore, we observed unique and almost non-overlapping metabolite profiles in both studies. In conclusion, we established the feasibility of using GCxGC/TOF-MS for detecting metabolites as well as developed software to align and merge chromatographic peaks to compare metabolite differences between invertebrate groups sampled under different environmental conditions. This ability to detect unique metabolite profiles under different environmental conditions will increase our undertsanding on the physiological processes and whole-organism reponses occuring as a result of exposure to different environmental stressors. PMID:18423646

Ralston-Hooper, Kimberly; Hopf, Amber; Oh, Cheolhwan; Zhang, Xiang; Adamec, Jiri; Sepúlveda, Maria S

2008-06-01

74

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

75

Rapid determination of total solanesol in tobacco leaf by ultrasound-assisted extraction with RP-HPLC and ESI-TOF\\/MS  

Microsoft Academic Search

A reliable and rapid method based on high-performance liquid chromatography (HPLC-UV) and positive ion electrospray-time of flight mass spectrometry (ESI-TOF\\/MS) has been developed for the characterization and quantification of solanesol in extracts of tobacco leaves from different sources. The solanesol was extracted from tobacco leaf via saponification and ultrasonic-assist extraction, and the extraction conditions were optimized. The HPLC conditions are

Junhui Chen; Xianping Liu; Xiaoqin Xu; Frank Sen-Chun Lee; Xiaoru Wang

2007-01-01

76

MALDI-TOF MS and TaqMan assisted SNP genotyping of DNA isolated from formalin-fixed and paraffin-embedded tissues (FFPET).  

PubMed

Formalin-fixed paraffin-embedded tissues (FFPET) from archived clinical samples provide an invaluable source for large-scale molecular genetic studies. Pharmacogenetic investigations that require long-term clinical follow-up data of patients may particularly benefit from FFPET analysis. Matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and TaqMan-based (Thermus aquaticus polymerase) methodologies have become standard genotyping procedures. However, no data are available on the applicability of MALDI-TOF MS to the genotyping of low quality DNA, as it is usually obtained from FFPET, and data from TaqMan genotyping are limited. We isolated constitutional DNA from 274 FFPET samples (229 patients with breast cancer and 45 patients with benign breast diseases) and genotyped 15 polymorphic loci in 10 genes. Nine SNPs were genotyped by MALDI-TOF MS, and six were genotyped by the TaqMan methodology. We established rates for successful allele assignment for all FFPET, for FFPET prepared prior to 1990, and for FFPET prepared post-1990. Both methodologies showed high success rates ranging between 70.9 and 99.6% (mean: 91.8%) for MALDI-TOF MS and between 82.3 and 97.7% (mean: 91.0%) for TaqMan genotyping. No significant differences in genotyping performances for FFPET prepared prior to 1990 or post-1990 were observed. With the exception of one, all other genotype frequencies were in Hardy-Weinberg equilibrium. Furthermore, genotype frequencies matched those observed in a German breast cancer population and other Caucasian populations. Our study shows for the first time that MALDI-TOF MS and TaqMan genotyping procedures provide reliable data, and are therefore applicable in studies that require large scale FFPET genotyping. PMID:15706592

Jaremko, Malgorzata; Justenhoven, Christina; Abraham, Benny K; Schroth, Werner; Fritz, Peter; Brod, Sandra; Vollmert, Caren; Illig, Thomas; Brauch, Hiltrud

2005-03-01

77

The MALDI-TOF Mass Spectrometric View of the Plasma Proteome and Peptidome  

Microsoft Academic Search

Background: Matrix-assisted laser desorption\\/ioniza- tion time-of-flight mass spectrometry (MALDI-TOF MS) and the related technique, surface-enhanced laser desorption\\/ionization (SELDI)-TOF MS, are being ap- plied widely to analyze serum or plasma specimens for potential disease markers. Methods: Reports on the basic principles and applica- tions of MALDI-TOF MS were reviewed and related to information on abundance and masses of major plasma proteins.

Glen L. Hortin

2006-01-01

78

Analysis of Combustion Chamber Deposits by ESI-TOF-MS and MALDI-TOF-MS  

SciTech Connect

Combustion chamber deposits (CCDs) in internal combustion engines have been studied by various techniques to understand the relationship of performance degradation with deposit quantity and structure. XPS, XAS, NMR, and elemental analysis have offered insight into the bulk structure of C, H, N, O and metal components [1]. MS has offered some information about compound structure, but results are limited due to the insolubility and complexity of the materials. Recent advances in MS have opened new possibilities for analysis of CCDs. Here we report initial findings on the carbon structure of these deposits determined by ESI-TOF-MS and MADLI-TOF-MS.

Reynolds, J G; Shields, S J; Roos, J W

2001-06-14

79

Qualitative and quantitative analysis of the constituents in Danmu preparations by UPLC-PDA-TOF-MS.  

PubMed

An ultra performance liquid chromatography coupled with photodiode array detector and time-of-flight tandem mass spectrometry (UPLC-PDA-TOF-MS) method was developed for the quality assessment of Danmu preparations, a commonly used traditional Chinese medicine. Thirty-three compounds from Danmu preparations were simultaneously detected; among them, 14 compounds were unequivocally identified based on their retention behaviors, UV spectrum, MS and MS(n) data by comparing with reference substances, and the others were tentatively characterized by literatures. Twelve of 33 compounds were simultaneously determined by UPLC-PDA, and the validation of the quantitative method, including recoveries, linearity, sensitivity, precision and repeatability was carried out and the results demonstrated to be satisfied the requirements of quantitative analysis. The results suggested that the established method would be a powerful and reliable analytical tool for quality control of Danmu preparations and the characterization of multi-constituent in complex chemical system. PMID:23988988

Zhu, Fenxia; Chen, Jiaquan; Wang, Jingjing; Yin, Rong; Li, Xiufeng; Jia, Xiaobin

2014-09-01

80

UPLC-Q-TOF-MS/MS fingerprinting of Traditional Chinese Formula SiJunZiTang.  

PubMed

SiJunZiTang (SJZT), a classic Traditional Chinese Formula (TCMF) consisting of four herbs, Radix Ginseng, Atractylodes macrocephala, Poria cocos and Glycyrrhiza uralensis, has been demonstrated to show protective effects on intestine and stomach injure. The chromatographic quality control is needed. UPLC-Q-TOF-MS is a rapid and efficient technique for analysis of complex sample in combination with UPLC and tandem mass spectrometry (MS/MS). In this paper, UPLC-MS fingerprinting of SJZT was developed. As a result, 66 compounds including ginsenosides, flavonoids, triterpenoid and coumarins were detected, 58 of them were tentatively identified. The major constituents of SJZT were ginsenosides and flavonoids that coming from Radix Ginseng and Glycyrrhiza uralensis. PMID:23511229

Wang, Yanyan; He, Shan; Cheng, Xiaochen; Lu, Yuxin; Zou, Yunpeng; Zhang, Qinglin

2013-06-01

81

High-Throughput Identification of Bacteria and Yeast by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry in Conventional Medical Microbiology Laboratories ?  

PubMed Central

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is suitable for high-throughput and rapid diagnostics at low costs and can be considered an alternative for conventional biochemical and molecular identification systems in a conventional microbiological laboratory. First, we evaluated MALDI-TOF MS using 327 clinical isolates previously cultured from patient materials and identified by conventional techniques (Vitek-II, API, and biochemical tests). Discrepancies were analyzed by molecular analysis of the 16S genes. Of 327 isolates, 95.1% were identified correctly to genus level, and 85.6% were identified to species level by MALDI-TOF MS. Second, we performed a prospective validation study, including 980 clinical isolates of bacteria and yeasts. Overall performance of MALDI-TOF MS was significantly better than conventional biochemical systems for correct species identification (92.2% and 83.1%, respectively) and produced fewer incorrect genus identifications (0.1% and 1.6%, respectively). Correct species identification by MALDI-TOF MS was observed in 97.7% of Enterobacteriaceae, 92% of nonfermentative Gram-negative bacteria, 94.3% of staphylococci, 84.8% of streptococci, 84% of a miscellaneous group (mainly Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella [HACEK]), and 85.2% of yeasts. MALDI-TOF MS had significantly better performance than conventional methods for species identification of staphylococci and genus identification of bacteria belonging to HACEK group. Misidentifications by MALDI-TOF MS were clearly associated with an absence of sufficient spectra from suitable reference strains in the MALDI-TOF MS database. We conclude that MALDI-TOF MS can be implemented easily for routine identification of bacteria (except for pneumococci and viridans streptococci) and yeasts in a medical microbiological laboratory. PMID:20053859

van Veen, S. Q.; Claas, E. C. J.; Kuijper, Ed J.

2010-01-01

82

Novel Mass Spectrometry-Based Tool for Genotypic Identification of Mycobacteria  

Microsoft Academic Search

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) after base-specific cleavage of PCR amplified and in vitro-transcribed 16S rRNA gene (rDNA) was used for the identification of mycobacteria. Full-length 16S rDNA reference sequences of 12 type strains of Mycobacterium spp. frequently isolated from clinical specimens were determined by PCR, cloning, and sequencing. For MALDI-TOF MS-based comparative sequence analysis,

Michael Lefmann; Christiane Honisch; Sebastian Bocker; Niels Storm; Cord Schlotelburg; Annette Moter; Dirk van den Boom; Ulf B. Gobel

2004-01-01

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

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

85

Determination of biogenic volatile organic compound fluxes from Harvard Forest using PTR-TOF-MS (Invited)  

NASA Astrophysics Data System (ADS)

Forest emissions of biogenic volatile organic compounds (BVOCs) are the largest source of reactive non-methane hydrocarbons to the atmosphere, yet studies suggest that the understanding of the nature and quantity of emitted compounds remains incomplete. Recent findings have indicated the presence of reactive BVOCs within and above forest canopies that have not been quantified previously. Here we report new measurements of BVOC emissions from and concentrations above Harvard Forest, a mixed forest in the Eastern U.S., from June 8 to September 30, 2012 using Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-TOF-MS). PTR-TOF-MS represents an advance over previous quadrupole-based PTR-MS measurements in that it captures a full, high-resolution (m/?m ca. 4000) mass spectrum on every scan, resulting in positive identification of molecular formulas. In addition, scans are recorded at high time resolution (5 Hz), allowing true (non-disjunct) eddy covariance fluxes to be determined for each mass-to-charge ratio. Concentration and flux measurements were made simultaneously using a high-sensitivity quadrupole PTR-MS, and results from the two techniques are compared. Measured concentrations of most species agree to within 5%. As in past seasons, isoprene is the major BVOC emitted at Harvard Forest, reaching average midday mixing ratios of ca. 4 ppbv, and its emissions are closely tied to local temperature and light levels. Diurnal and seasonal patterns in emissions of isoprene, monoterpenes, methanol, acetone, and MEK are reported and compared with past measurements at the site. In addition, eddy covariance fluxes are calculated for all mass peaks to assess emissions of previously unidentified BVOCs from Harvard Forest.

McKinney, K. A.; Munger, J. W.; Liu, Y.

2013-12-01

86

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

87

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, Joao; Pintado, Manuela E.; Peixe, Luisa V.; Osorio, Hugo

2014-01-01

88

Neutral particle Mass Spectrometry with Nanomechanical Systems  

E-print Network

Current approaches to Mass Spectrometry (MS) necessarily rely on the ionization of the analytes of interest and subsequent spectrum interpretation is based on the mass-to-charge ratios of the ions. The resulting charge state distribution can be very complex for high-mass species which may hinder correct interpretation. A new form of MS analysis based on Nano-Electro-Mechanical Systems (NEMS) was recently demonstrated with high-mass ions. Thanks to a dedicated setup comprising both conventional time-of-flight MS (TOF-MS) and NEMS-MS in-situ, we show here for the first time that NEMS-MS analysis is insensitive to charge state: it provides one single peak regardless of the species charge state, highlighting effective clarification over existing MS analysis. All charged particles were thereafter removed from the beam electrostatically, and unlike TOF-MS, NEMS-MS retained its ability to perform mass measurements. This constitutes the first unequivocal measurement of mass spectra of neutral particles. This ability ...

Sage, Eric; Alava, Thomas; Morel, Robert; Dupré, Cécilia; Hanay, Mehmet Selim; Duraffourg, Laurent; Masselon, Christophe; Hentz, Sébastien

2014-01-01

89

LC-ESI-Q-TOF-MS for faster and accurate determination of microcystins and nodularins in serum.  

PubMed

Microcystins (MC) and nodularins (Nod) are cyclic peptide hepatotoxins and tumour promoters produced by cyanobacteria. This study deals with liquid chromatography-mass spectrometry (LC-MS) analyses of 9 major cyanobacterial peptide toxins, starting with a comparison of six small particle size reversed-phase HPLC columns, from which one, Phenomenex Synergi Hydro-RP, was chosen for further chromatography with accurate mass MS studies in a complex biological fluid, serum. The instrumentation used for the serum sample analysis included a Bruker micrO-TOF-Q-MS coupled to an Agilent 1200RR LC system. Total analysis run time per sample was 8.5 min. The Q-TOF-MS instrument was operated on auto MS-MS mode to obtain fragment ions (such as the characteristic fragment m/z 135 from Adda amino acid residue) for toxin identification purposes. Detected mass errors in serum samples were in the range of from 0.3 mDa to 9.1 mDa. The narrow mass window (+/-20 mDa) for mass chromatograms used in quantitation gave benefits by background noise reduction. We conclude that a LC-ESI-Q-TOF-MS instrumentation is a powerful tool for identification and quantitation of cyanobacterial peptide toxins in a biological matrix. PMID:20724233

Neffling, Milla-Riina; Spoof, Lisa; Quilliam, Michael; Meriluoto, Jussi

2010-09-15

90

The application of SELDI-TOF mass spectrometry to mammalian cell culture  

Microsoft Academic Search

Surface Enhanced Laser Desorption\\/Ionisation Time-of-Fight Mass Spectrometry (SELDI-TOF MS) is a technique by which protein profiles can be rapidly produced from a wide variety of biological samples. By employing chromatographic surfaces combined with the specificity and reproducibility of mass spectrometry it has allowed for profiles from complex biological samples to be analysed. Profiling and biomarker identification have been employed widely

John F. Woolley; Mohamed Al-Rubeai

2009-01-01

91

Analysis of Combustion Chamber Deposits by ESI-TOF-MS and MALDI-TOF-MS  

SciTech Connect

Combustion chamber deposits (CCD) in internal combustion engines have been studied by various techniques to understand the relationship of performance degradation with deposit quantity and structure. XPS, XAS, NMR, and elemental analysis have offered insight into the bulk structure of C, H, N, O and metal components. MS has offered some information about compound structure, but results are limited due to the insolubility and complexity of the materials. Recently, we have reported on the metal structure by XPS and XAS of several deposits from a GM 3800 engine generated using a standard fuel and one that contains low levels of the gasoline anti-knock additive, MMT. Here we report the initial findings on the carbon structure of these deposits determined by ESI-TOF-MS and MADLI-TOF-MS.

Reynolds, J G; Shields, S J; Roos, J W

2001-06-14

92

Characterization of polyoxyalkylene block copolymers by combination of different chromatographic techniques and MALDI-TOF-MS.  

PubMed

Polyoxyalkylene diblock copolymers (consisting of PEO as hydrophilic block and PBO or PHO as hydrophobic block) are characterized by combination of two dimensional liquid chromatography and MALDI-TOF-MS. Liquid chromatography under critical conditions (LCCC) is used as first dimension and fractions are collected, mobile phase evaporated and diluted in the mobile phase used in the second dimension (SEC, LCCC or LAC). This two-dimensional chromatography in combination of MALDI-TOF-MS gives information about purity of reaction products, presence of the byproducts, chemical composition and molar mass distribution of all the products. PMID:20103098

Malik, Muhammad Imran; Trathnigg, Bernd; Bartl, Karin; Saf, Robert

2010-01-25

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

MALDI-TOF MS for the identification of veterinary non-C. neoformans-C. gattii Cryptococcus spp. isolates from Italy.  

PubMed

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) offers an effective alternative to phenotypic and molecular methods for the rapid identification of microorganisms. Our aim in this study was to create an in-house library for a set of strains of nine uncommonly reported human and animal cryptococcal species, including Cryptococcus adeliensis, C. albidosimilis, C. albidus, C. aureus, C. carnescens, C. laurentii, C. magnus, C. victoriae and C. uniguttulatus, and to use this library to make timely and correct identifications using MALDI-TOF MS for use in routine laboratory diagnostics. Protein extracts obtained via the formic acid extraction method of 62 veterinary non-C. neoformans-C. gattii cryptococcal isolates were studied. The obtained mass spectra correctly grouped all 62 studied isolates according to species identification previously obtained by internal transcribe spacer sequence analysis. The in-house database was than exported and successfully uploaded to the Microflex LT (Maldi Biotyper; Bruker Daltonics) instrument at a different diagnostic laboratory in Italy. Scores >2.7 obtained from isolates reanalyzed in the latter laboratory supported the high reproducibility of the method. The possibility of creating and transferring an in-house library adds to the usefulness MALDI-TOF MS an important tool for the rapid and inexpensive identification of pathogenic and saprophytic fungi as required for differential diagnosis of human and animal mycoses. PMID:24951721

Danesi, Patrizia; Drigo, Ilenia; Iatta, Roberta; Firacative, Carolina; Capelli, Gioia; Cafarchia, Claudia; Meyer, Wieland

2014-08-01

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

Use of electrophoretic techniques and MALDI-TOF MS for rapid and reliable characterization of bacteria: analysis of intact cells, cell lysates, and "washed pellets".  

PubMed

In this study electrophoretic and mass spectrometric analysis of three types of bacterial sample (intact cells, cell lysates, and "washed pellets") were used to develop an effective procedure for the characterization of bacteria. The samples were prepared from specific bacterial strains. Five strains representing different species of the family Rhizobiaceae were selected as model microorganisms: Rhizobium leguminosarum bv. trifolii, R. leguminosarum bv. viciae, R. galegae, R. loti, and Sinorhizobium meliloti. Samples of bacteria were subjected to analysis by four techniques: capillary zone electrophoresis (CZE), capillary isoelectric focusing (CIEF), gel IEF, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). These methods are potential alternatives to DNA-based methods for rapid and reliable characterization of bacteria. Capillary electrophoretic (CZE and CIEF) analysis of intact cells was suitable for characterization of different bacterial species. CIEF fingerprints of "washed pellets" and gel IEF of cell lysates helped to distinguish between closely related bacterial species that were not sufficiently differentiated by capillary electrophoretic analysis of intact cells. MALDI-TOF MS of "washed pellets" enabled more reliable characterization of bacteria than analysis of intact cells or cell lysates. Electrophoretic techniques and MALDI-TOF MS can both be successfully used to complement standard methods for rapid characterization of bacteria. PMID:23388690

Salplachta, Ji?í; Kubesová, Anna; Moravcová, Dana; Vykydalová, Marie; Süle, Sándor; Matoušková, Hana; Horký, Jaroslav; Horká, Marie

2013-04-01

97

Relative quantitation of glycopeptides based on stable isotope labeling using MALDI-TOF MS.  

PubMed

We have developed an effective, sensitive method for quantitative glycopeptide profiling using stable isotope labeling and MALDI-TOF mass spectrometry (MS). In this study, we synthesized benzoic acid-d0 N-succinimidyl ester (BzOSu) and benzoic acid-d5 N-succinimidyl ester (d-BzOSu) as light and heavy isotope reagents for stable isotope quantification for the comparative analysis of glycopeptides. Using this approach provided enhanced ionization efficiency in both positive and negative modes by MALDI-TOF MS. These reagents were quantitatively reacted with glycopeptides from human serum IgG (hIgG) at a wide range of concentrations; the labeling efficiency of the glycopeptides showed high reproducibility and a good calibration curve was obtained. To demonstrate the practical utility of this approach, we characterized the structures of glycopeptides from hIgG and from IgG1 produced by myeloma plasma. The glycopeptides were quantitatively analyzed by mixing Bz-labeled IgG1 glycopeptides with d-Bz-labeled hIgG glycopeptides. Glycan structural identification of the hIgG glycopeptides was demonstrated by combining the highly specific recognition of endo-?-N-acetyl glucosaminidases from Streptococcus pyogenes (endoS) or from Streptococcus pneumoniae (endo-D) with MALDI-TOF MS analysis. The obtained data revealed the glycan profile and the ratio of glycan structural isomers containing a galactosylated extension on IgG1, IgG2 and IgG3 glycopetides. PMID:25010467

Kurogochi, Masaki; Amano, Junko

2014-01-01

98

Quantitative determination of acetylcholine and choline in microdialysis samples by MALDI-TOF MS.  

PubMed

A simple, sensitive, and fast matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) method was developed for the determination of acetylcholine (ACh) and choline (Ch) in microdialysis samples. An optimized dried droplet preparation with the common matrix alpha-cyano-4-hydroxycinnamic acid (CHCA) was used. Limits of detection [signal-to-noise ratio (S/N) = 3] of 0.3 fmol/microL for ACh and 20 fmol/microL for Ch were found using standards diluted in artificial cerebrospinal fluid (aCSF). The limit of quantification (LOQ) for ACh was 1 fmol/microL, and excellent linearity (R(2) = 0.9996) was maintained over the range of 1-1000 fmol/microL. Choline was quantified over the range of 0.1-50 pmol/microL, also with excellent linearity (R(2) = 0.9995). Good accuracy and precision were obtained for all concentrations within the range of the standard curve. The developed method was successfully used for the determination of ACh and Ch in mouse brain microdialysis samples. The samples were quantified by a calibration curve and also by the method of standard addition. Despite the high salt content of the perfusion fluid (>150 mM), a direct measurement was possible. To the authors' knowledge, this is the first published method to determine acetylcholine and choline in microdialysis samples by MALDI-TOF MS. The method presented significantly reduces the needed analysis time, as only approximately 10 s/sample is required, and it is also possible to improve the temporal resolution, because only approximately 1 microL of sample is needed. PMID:20058877

Persike, Markus; Zimmermann, Martina; Klein, Jochen; Karas, Michael

2010-02-01

99

MALDI-TOF MS versus VITEK 2 ANC card for identification of anaerobic bacteria  

PubMed Central

Background Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is an accurate, rapid and inexpensive technique that has initiated a revolution in the clinical microbiology laboratory for identification of pathogens. The Vitek 2 anaerobe and Corynebacterium (ANC) identification card is a newly developed method for identification of corynebacteria and anaerobic species. The aim of this study was to evaluate the effectiveness of the ANC card and MALDI-TOF MS techniques for identification of clinical anaerobic isolates. Methods Five reference strains and a total of 50 anaerobic bacteria clinical isolates comprising ten different genera and 14 species were identified and analyzed by the ANC card together with Vitek 2 identification system and Vitek MS together with version 2.0 database respectively. 16S rRNA gene sequencing was used as reference method for accuracy in the identification. Results Vitek 2 ANC card and Vitek MS provided comparable results at species level for the five reference strains. Of 50 clinical strains, the Vitek MS provided identification for 46 strains (92%) to the species level, 47 (94%) to genus level, one (2%) low discrimination, two (4%) no identification and one (2%) misidentification. The Vitek 2 ANC card provided identification for 43 strains (86%) correct to the species level, 47 (94%) correct to the genus level, three (6%) low discrimination, three (6%) no identification and one (2%) misidentification. Conclusions Both Vitek MS and Vitek 2 ANC card can be used for accurate routine clinical anaerobe identification. Comparing to the Vitek 2 ANC card, Vitek MS is easier, faster and more economic for each test. The databases currently available for both systems should be updated and further developed to enhance performance. PMID:24822113

Li, Yang; Gu, Bing; Xia, Wenying; Fan, Kun; Mei, Yaning; Huang, Peijun; Pan, Shiyang

2014-01-01

100

GyrB sequence analysis and MALDI-TOF MS as identification tools for plant pathogenic Clavibacter.  

PubMed

The bacterial genus Clavibacter has only one species, Clavibacter michiganensis, containing five subspecies. All five are plant pathogens, among which three are recognized as quarantine pests (mentioned on the EPPO A2 list). Prevention of their introduction and epidemic outbreaks requires a reliable and accurate identification. Currently, identification of these bacteria is time consuming and often problematic, mainly because of cross-reactions with other plant-associated bacteria in immunological tests and false-negative results in PCR detection methods. Furthermore, distinguishing closely related subspecies is not straightforward. This study aimed at evaluating the use of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and a fragment of the gyrB sequence for the reliable and fast identification of the Clavibacter subspecies. Amplification and sequencing of gyrB using a single primer set had sufficient resolution and specificity to identify each subspecies based on both sequence similarities in cluster analyses and specific signatures within the sequences. All five subspecies also generated distinct and reproducible MALDI-TOF MS profiles, with unique and specific ion peaks for each subspecies, which could be used as biomarkers for identification. Results from both methods were in agreement and were able to distinguish the five Clavibacter subspecies from each other and from representatives of closely related Rathayibacter, Leifsonia or Curtobacterium species. Our study suggests that proteomic analysis using MALDI-TOF MS and gyrB sequence are powerful diagnostic tools for the accurate identification of Clavibacter plant pathogens. PMID:21802235

Zaluga, Joanna; Heylen, Kim; Van Hoorde, Koenraad; Hoste, Bart; Van Vaerenbergh, Johan; Maes, Martine; De Vos, Paul

2011-09-01

101

[Identification of chemical components of mahuang decoction by GC-MS and UPLC-Q-TOF-MS].  

PubMed

Since the polyjuice potion ingredient is complex, we need to develop an analysis method with well separation and high stability to perform qualitative analysis. After dividing chemical components of Mahuang Decoction into fat-soluble and water-soluble constituents by gradient extraction, GC-MS was used to analyze the chemical components of the ethyl acetate extraction. The results showed that forty compounds had been identified by NIST MS search 2.0 standard mass spectrometry Library and literatures. Next, UPLC-Q-TOF-MS was applied to idendify the chemical components of the water extraction. The results showed that thirty-nine compounds had been identified by MZmine-2.9.1, Isotope Pattern, fragmentation regularity of mass spectrometry and literatures. This experiment will provide evidences for elucidation of the effective substance in Mahuang decoction and can be used as a simple, shortcut method for analysis and identification for the polyjuice potion. PMID:25204151

Li, Rui; Zeng, Cen; Wang, Ping; Meng, Xian-Li; Zeng, Yong

2014-02-01

102

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

103

Wavelet-based adaptive denoising and baseline correction for MALDI TOF MS.  

PubMed

Proteomic profiling by MALDI TOF mass spectrometry (MS) is an effective method for identifying biomarkers from human serum/plasma, but the process is complicated by the presence of noise in the spectra. In MALDI TOF MS, the major noise source is chemical noise, which is defined as the interference from matrix material and its clusters. Because chemical noise is nonstationary and nonwhite, wavelet-based denoising is more effective than conventional noise reduction schemes based on Fourier analysis. However, current wavelet-based denoising methods for mass spectrometry do not fully consider the characteristics of chemical noise. In this article, we propose new wavelet-based high-frequency noise reduction and baseline correction methods that were designed based on the discrete stationary wavelet transform. The high-frequency noise reduction algorithm adaptively estimates the time-varying threshold for each frequency subband from multiple realizations of chemical noise and removes noise from mass spectra of samples using the estimated thresholds. The baseline correction algorithm computes the monotonically decreasing baseline in the highest approximation of the wavelet domain. The experimental results demonstrate that our algorithms effectively remove artifacts in mass spectra that are due to chemical noise while preserving informative features as compared to commonly used denoising methods. PMID:20455751

Shin, Hyunjin; Sampat, Mehul P; Koomen, John M; Markey, Mia K

2010-06-01

104

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.

105

Species Identification of Clinical Prevotella Isolates by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry  

PubMed Central

The performance of matrix-assisted laser desorption–ionization time of flight mass spectrometry (MALDI-TOF MS) for species identification of Prevotella was evaluated and compared with 16S rRNA gene sequencing. Using a Bruker database, 62.7% of the 102 clinical isolates were identified to the species level and 73.5% to the genus level. Extension of the commercial database improved these figures to, respectively, 83.3% and 89.2%. MALDI-TOF MS identification of Prevotella is reliable but needs a more extensive database. PMID:22301022

Soetens, Oriane; De Bel, Annelies; Echahidi, Fedoua; Vancutsem, Ellen; Vandoorslaer, Kristof; Pierard, Denis

2012-01-01

106

Leptospira spp. strain identification by MALDI TOF MS is an equivalent tool to 16S rRNA gene sequencing and multi locus sequence typing (MLST)  

PubMed Central

Background In this study mass spectrometry was used for evaluating extracted leptospiral protein samples and results were compared with molecular typing methods. For this, an extraction protocol for Leptospira spp. was independently established in two separate laboratories. Reference spectra were created with 28 leptospiral strains, including pathogenic, non-pathogenic and intermediate strains. This set of spectra was then evaluated on the basis of measurements with well-defined, cultured leptospiral strains and with 16 field isolates of veterinary or human origin. To verify discriminating peaks for the applied pathogenic strains, statistical analysis of the protein spectra was performed using the software tool ClinProTools. In addition, a dendrogram of the reference spectra was compared with phylogenetic trees of the 16S rRNA gene sequences and multi locus sequence typing (MLST) analysis. Results Defined and reproducible protein spectra using MALDI-TOF MS were obtained for all leptospiral strains. Evaluation of the newly-built reference spectra database allowed reproducible identification at the species level for the defined leptospiral strains and the field isolates. Statistical analysis of three pathogenic genomospecies revealed peak differences at the species level and for certain serovars analyzed in this study. Specific peak patterns were reproducibly detected for the serovars Tarassovi, Saxkoebing, Pomona, Copenhageni, Australis, Icterohaemorrhagiae and Grippotyphosa. Analysis of the dendrograms of the MLST data, the 16S rRNA sequencing, and the MALDI-TOF MS reference spectra showed comparable clustering. Conclusions MALDI-TOF MS analysis is a fast and reliable method for species identification, although Leptospira organisms need to be produced in a time-consuming culture process. All leptospiral strains were identified, at least at the species level, using our described extraction protocol. Statistical analysis of the three genomospecies L. borgpetersenii, L. interrogans and L. kirschneri revealed distinctive, reproducible differentiating peaks for seven leptospiral strains which represent seven serovars. Results obtained by MALDI-TOF MS were confirmed by MLST and 16S rRNA gene sequencing. PMID:22925589

2012-01-01

107

Powerful GC-TOF-MS Techniques for Screening, Identification and Quantification of Halogenated Natural Products  

PubMed Central

Comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC TOFMS) and gas chromatography/high-resolution time-of-flight mass spectrometry (GC-HRT) were used to detect and identify halogenated natural products (HNPs) in tissue homogenate, in this case brominated analytes present in a marine snail. Two classes of brominated anthropogenic compounds, polybrominated diphenyl ethers (PBDEs) and brominated dibenzofurans, were analyzed for comparison. Following conventional preparation, the sample was analyzed using GC×GC-TOF-MS. Isotope ratio scripts were used to compile a list of putatively brominated analytes from amongst the thousands of features resolved in the two-dimensional chromatogram. The structured nature of the chromatogram was exploited to propose identifications for several classes of brominated compounds, and include additional candidates that fell marginally outside the script tolerances. The sample was subsequently analyzed by GC-HRT. The high-resolution mass spectral data confirmed many formula assignments, facilitated confident assignment of an alternate formula when an original proposal did not hold, and enabled unknown identification. Identified HNPs include hydroxylated and methoxylated PBDE analogs, polybrominated dibenzo-p-dioxins (PBDDs) and hydroxyl-PBDDs, permitting the environmental occurrence and fate of such compounds to be studied. PMID:24349937

S. Haglund, Peter; Lofstrand, Karin; Siek, Kevin; Asplund, Lillemor

2013-01-01

108

Powerful GC-TOF-MS Techniques for Screening, Identification and Quantification of Halogenated Natural Products.  

PubMed

Comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC TOFMS) and gas chromatography/high-resolution time-of-flight mass spectrometry (GC-HRT) were used to detect and identify halogenated natural products (HNPs) in tissue homogenate, in this case brominated analytes present in a marine snail. Two classes of brominated anthropogenic compounds, polybrominated diphenyl ethers (PBDEs) and brominated dibenzofurans, were analyzed for comparison. Following conventional preparation, the sample was analyzed using GC×GC-TOF-MS. Isotope ratio scripts were used to compile a list of putatively brominated analytes from amongst the thousands of features resolved in the two-dimensional chromatogram. The structured nature of the chromatogram was exploited to propose identifications for several classes of brominated compounds, and include additional candidates that fell marginally outside the script tolerances. The sample was subsequently analyzed by GC-HRT. The high-resolution mass spectral data confirmed many formula assignments, facilitated confident assignment of an alternate formula when an original proposal did not hold, and enabled unknown identification. Identified HNPs include hydroxylated and methoxylated PBDE analogs, polybrominated dibenzo-p-dioxins (PBDDs) and hydroxyl-PBDDs, permitting the environmental occurrence and fate of such compounds to be studied. PMID:24349937

S Haglund, Peter; Löfstrand, Karin; Siek, Kevin; Asplund, Lillemor

2013-01-01

109

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

110

Characterization of the cultivable microbial community in a spinach-processing plant using MALDI-TOF MS.  

PubMed

A better and regular control of the production chain of fresh fruits and vegetables is necessary, because a contamination of the product by human- and phyto-pathogenic microorganisms may result in high losses during storage and poses a threat to human health. Therefore, detailed knowledge about the occurrence and the diversity of microorganisms within single processing steps is required to allow target-oriented produce safety control. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was successfully used to identify bacterial colonies. Bacteria can be identified with high accuracy by comparing them with generated spectra of a reference database. In this study, spinach and wash water samples were taken of the complete process line of a spinach-washing plant. Bacteria in the samples were grown on plate-count, Arcobacter selective, marine and blood agar. In total, 451 colonies were evaluated by MALDI-TOF MS, 16S rRNA gene sequence and phylogenetic analysis. 50% of the detected species belonged to the class of Gammaproteobacteria. Firmicutes were present with 22%. Mostly, the detected species showed 16S rRNA gene sequence dissimilarities larger than 1% to known reference species and, hence, could not be assigned to a distinct species. However, many isolated species belonged to genera which contain pathogenic or opportunistic pathogenic bacteria. In addition, the bacterial diversity on the spinach surface increased after the first washing step indicating a process-borne contamination of the spinach. PMID:23541209

Hausdorf, Lena; Mundt, Kerstin; Winzer, Michaela; Cordes, Christiana; Fröhling, Antje; Schlüter, Oliver; Klocke, Michael

2013-06-01

111

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

112

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

113

Gas chromatography/multiphoton ionization/time-of-flight mass spectrometry using a femtosecond laser.  

PubMed

A laser can be used for the selective excitation and subsequent ionization of a molecule with an absorption band at the laser wavelength. This technique of multiphoton ionization (MPI), when combined with time-of-flight mass spectrometry (TOF-MS), permits the efficient detection of induced ions in mass analysis. This combination of MPI/TOF-MS can be coupled with gas chromatography (GC) to achieve even more enhanced selectivity. Thus, GC/MPI/TOF-MS can be employed for trace analysis of samples containing numerous chemical species. A variety of laser sources have been used for this purpose. Since molecules that are classified as environmental pollutants frequently contain chlorine and bromine atoms, the lifetime of the excited state can be decreased by energy transfer from the singlet to triplet levels by spin-orbit interaction. A high-power femtosecond laser with a pulse width shorter than the lifetime of the analyte molecule provides femtogram or even subfemtogram detection limits, which have not yet been achieved using the most sensitive high-resolution double-focus sector-type mass spectrometers. Numerous environmental pollutants such as dioxins in soils and pesticides in foods have been successfully quantified using GC/MPI/TOF-MS, and this technique has proven itself to be a useful and practical method for trace analysis. PMID:23612871

Imasaka, Totaro

2013-09-01

114

Reliable genotyping of short tandem repeat loci without an allelic ladder using time-of-flight mass spectrometry  

Microsoft Academic Search

DNA separations which traditionally have been performed by slab gel or capillary electrophoresis, may now be conducted via\\u000a time-of-flight mass spectrometry (TOF-MS). The advantages of using a mass spectrometry approach for short tandem repeat (STR)\\u000a characterization include a dramatic increase in both the speed of analysis and the accuracy of mass measurements. We report\\u000a here typing of the STR loci

J. M. Butler; J. Li; T. A. Shaler; J. A. Monforte; C. H. Becker

1998-01-01

115

Phenotyping polyclonal kappa and lambda light chain molecular mass distributions in patient serum using mass spectrometry.  

PubMed

We previously described a microLC-ESI-Q-TOF MS method for identifying monoclonal immunoglobulins in serum and then tracking them over time using their accurate molecular mass. Here we demonstrate how the same methodology can be used to identify and characterize polyclonal immunoglobulins in serum. We establish that two molecular mass distributions observed by microLC-ESI-Q-TOF MS are from polyclonal kappa and lambda light chains using a combination of theoretical molecular masses from gene sequence data and the analysis of commercially available purified polyclonal IgG kappa and IgG lambda from normal human serum. A linear regression comparison of kappa/lambda ratios for 74 serum samples (25 hypergammaglobulinemia, 24 hypogammaglobulinemia, 25 normal) determined by microflowLC-ESI-Q-TOF MS and immunonephelometry had a slope of 1.37 and a correlation coefficient of 0.639. In addition to providing kappa/lambda ratios, the same microLC-ESI-Q-TOF MS analysis can determine the molecular mass for oligoclonal light chains observed above the polyclonal background in patient samples. In 2 patients with immune disorders and hypergammaglobulinemia, we observed a skewed polyclonal molecular mass distribution which translated into biased kappa/lambda ratios. Mass spectrometry provides a rapid and simple way to combine the polyclonal kappa/lambda light chain abundance ratios with the identification of dominant monoclonal as well as oligoclonal light chain immunoglobulins. We anticipate that this approach to evaluating immunoglobulin light chains will lead to improved understanding of immune deficiencies, autoimmune diseases, and antibody responses. PMID:25134970

Barnidge, David R; Dasari, Surendra; Ramirez-Alvarado, Marina; Fontan, Adrian; Willrich, Maria A V; Tschumper, Renee C; Jelinek, Diane F; Snyder, Melissa R; Dispenzieri, Angela; Katzmann, Jerry A; Murray, David L

2014-11-01

116

Normal silica gel and reversed phase thin-layer chromatography coupled with UV spectroscopy and IR-MALDI-o-TOF-MS for the detection of tetracycline antibiotics  

Microsoft Academic Search

Tetracyclines (TCs) form a group of bacteriostatic antibiotics with closely related structures and similar chemical and physicochemical\\u000a properties. They are widely employed as therapeutics in human and veterinary medicine. Here, we introduce the combination\\u000a of UV spectroscopic detection of high-performance thin-layer chromatography (HPTLC)-separated TCs with direct analysis on\\u000a solid phase using infrared matrix-assisted laser desorption\\/ionization orthogonal time-of-flight mass spectrometry (IR-MALDI-o-TOF-MS).

Iris Meisen; Sebastian Wisholzer; Jens Soltwisch; Klaus Dreisewerd; Michael Mormann; Johannes Müthing; Helge Karch; Alexander W. Friedrich

2010-01-01

117

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

PubMed Central

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

West, Brett J.; Jensen, C. Jarakae

2013-01-01

118

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

119

Application status of MALDI-TOF mass spectrometry in the identification and drug resistance of Mycobacterium tuberculosis  

PubMed Central

Characterizing Mycobacterium tuberculosis (MTB) and detecting its drug resistance are challenging for clinical laboratory diagnosis, largely due to its slow growth and higher rate of genetic mutation. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a revolutionary technique for the routine identification of microorganisms. In this review, we discuss the application status of mass spectrometry in the identification and drug resistance of M. tuberculosis. PMID:24822112

Zhang, Ruixue; Long, Yin; He, Wenfang; Hao, Xiaoke

2014-01-01

120

Proteomic Profiling of Hepatitis B Virus-related Hepatocellular Carcinoma in China: a SELDI-TOF-MS Study  

PubMed Central

Hepatocellular carcinoma (HCC) is one of the most common malignancies with high mortality, but its underlying molecular mechanisms remain not well understood. High-throughput, proteomic techniques targeting unique biological molecules may provide novel insights into HCC pathogenesis and prognosis. In this study, we systemically investigated tissue biomarkers of HCC by using surface-enhanced laser desorption and ionization time-of-flight mass spectrometry (SELDI-TOF-MS) technique. Proteomic spectra were generated from fresh tissues (26 HCC and 18 control cirrhotic liver) and analyzed by using Biomarker Wizard System. A total of 16 differential proteomic peaks were detected between HCC and cirrhotic liver tissues, and 11 between moderately and highly differentiated HCCs. The expression pattern of one proteomic peak was validated by immunohistochemistry. These molecules are potential candidate biomarkers for early diagnosis of and targeted therapy for HCC. PMID:18787613

Zhang, Jianzhong; Li, Dong; Zheng, Yanhua; Cui, Yan; Feng, Kai; Zhou, Jinlian; Wu, Jihua

2008-01-01

121

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

122

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. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24782425

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

2014-12-01

123

Characterization of Microorganisms by MALDI Mass Spectrometry  

SciTech Connect

Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) for characterization and analysis of microorganisms, specifically bacteria, is described here as a rapid screening tool. The objective of this technique is not comprehensive protein analysis of a microorganism but rather a rapid screening of the organism and the accessible protein pattern for characterization and distinction. This method is based on the ionization of the readily accessible and easily ionizable portion of the protein profile of an organism that is often characteristic of different bacterial species. The utility of this screening approach is yet to reach its full potential but could be applied to food safety, disease outbreak monitoring in hospitals, culture stock integrity and verification, microbial forensics or homeland security applications.

Petersen, Catherine E.; Valentine, Nancy B.; Wahl, Karen L.

2008-10-02

124

Identification of GYRKPPFNGSIFamide (crustacean-SIFamide) in the crayfish Procambarus clarkii by topological mass spectrometry analysis  

Microsoft Academic Search

A new concept relating to the purification protocol for biological proteins and peptides has been designed as “topological mass spectrometry analysis,” in combination with MALDI-TOF MS using slices of tissues, chromatographic purification from the extract of tissues, molecular cloning for the determination of the precursor structure, and capillary LC-MS\\/MS analysis for elucidation of its posttranslational modifications. In an actual application,

Akikazu Yasuda; Yoshimi Yasuda-Kamatani; Masumi Nozaki; Terumi Nakajima

2004-01-01

125

Mass spectrometry-based hepcidin measurements in serum and urine: analytical aspects and clinical implications  

Microsoft Academic Search

BACKGROUND: Discovery of the central role of hepcidin in body iron regulation has shed new light on the pathophysiology of iron disorders. Information is lacking on newer analytical approaches to measure hepcidin in serum and urine. Recent reports on the measurement of urine and serum hepcidin by surface-enhanced laser-desorption\\/ionization time-of-flight mass spectrometry (SELDI-TOF MS) necessitate analytical and clinical evaluation of

Erwin H. J. M. Kemna; Harold Tjalsma; Vladimir N. Podust; Dorine W. Swinkels

2007-01-01

126

Lipid Analysis by Matrix-Assisted Laser Desorption and Ionization Mass Spectrometry: A Methodological Approach  

Microsoft Academic Search

Whereas matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has gained high importance in the field of protein analysis, surprisingly few studies were published about the use of MALDI for lipid analysis. Lipids, however, are well-suited for MALDI since all experiments can be performed in a sole organic phase and, thus, extremely homogeneous matrix\\/analyte mixtures are formed. We report

J. Schiller; J. Arnhold; S. Benard; M. Müller; S. Reichl; K. Arnold

1999-01-01

127

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

128

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, Frederique; Fournier, Pierre Edouard; Drancourt, Michel; La Scola, Bernard

2013-01-01

129

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

130

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

131

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

132

Whole-cell matrix-assisted laser desorption\\/ionization time-of-flight mass spectrometry for rapid identification of bacteria cultured in liquid media  

Microsoft Academic Search

Matrix-assisted laser desorption\\/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been used for many years to\\u000a rapidly identify whole bacteria. However, no consistent methodology exists for the rapid identification of bacteria cultured\\u000a in liquid media. Thus, in this study we explored the use of MALDI-TOF MS analysis for rapid identification of cells cultured\\u000a in liquid media. We determined that 2,5-dihydroxybenzoic acid

Na Zhou; Na Wang; Bin Xu; Jie Wang; JunJian Fang; FangTing Dong; Kun He; XiaoHong Yang

2011-01-01

133

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, Th?ger Gorm; Kemp, Michael; Skov, Marianne Nielsine; Gahrn-Hansen, Bente; M?ller, Jens Kj?lseth

2011-01-01

134

Utility of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry following Introduction for Routine Laboratory Bacterial Identification ?  

PubMed Central

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) was evaluated prospectively in a diagnostic laboratory. Nine hundred twenty-seven organisms were tested in triplicate; 2,351/2,781 (85%) species and 2,681/2,781 (96%) genus identifications were correct. Known issues such as the misidentification of alpha-hemolytic streptococci as Streptococcus pneumoniae were easily corrected. Identifications cost AUD$0.45 per isolate and were available in minutes. MALDI-TOF MS is rapid, accurate, and inexpensive. PMID:21632894

Neville, Stephen A.; LeCordier, Annabelle; Ziochos, Helen; Chater, Mathew J.; Gosbell, Iain B.; Maley, Michael W.; van Hal, Sebastiaan J.

2011-01-01

135

Partially oxidised organic components in urban aerosol using GCXGC-TOF\\/MS  

Microsoft Academic Search

Partially oxidised organic compounds associated with PM2.5 aerosol collected in London, England, have been analysed using direct thermal desorption coupled to compre- hensive gas chromatography-time of flight mass spectrom- etry (GCXGC-TOF\\/MS). Over 10 000 individual organic components were isolated from around 10µg of aerosol ma- terial in a single procedure and with no sample pre-treatment. Chemical functionalities observed using this

J. F. Hamilton; P. J. Webb; A. C. Lewis; J. R. Hopkins; S. Smith; P. Davy

2004-01-01

136

Structural deviations in poly(amidoamine) dendrimers: a MALDI-TOF MS analysis  

Microsoft Academic Search

A step-by-step synthesis\\/purification (CC, HILIC, HPLC) of poly(amidoamine) PAMAM dendrimers was performed. MALDI-TOF MS in the linear and reflectron mode was used to analyze the purified samples and byproduct samples of G0–G5 generations of the dendrimers up to the mass of 35000 Da. DHB\\/fucose was found to give the best resolution, causing the least fragmentation of the samples. The precise

J Peterson; V Allikmaa; J Subbi; T Pehk; M Lopp

2003-01-01

137

Thin-layer chromatography–matrix-assisted laser desorption ionisation–time-of-flight mass spectrometry using particle suspension matrices  

Microsoft Academic Search

Particle suspension matrices have been successfully utilized for the analysis of tetracycline antibiotics by thin-layer chromatography–matrix-assisted laser desorption ionisation–time-of-flight mass spectrometry (TLC–MALDI–TOF–MS). Particles of different materials and sizes have been investigated (Co-UFP, TiN, TiO2, Graphite and Silicon) by applying particle suspensions to eluted TLC plates. Mass spectra and mass chromatograms have been recorded directly from the TLC plates. Strong cationization

Anna Crecelius; Malcolm R. Clench; Don S. Richards; Vic Parr

2002-01-01

138

Ion Mobility SpectrometryMass Spectrometry Performance Using Electrodynamic Ion Funnels and Elevated Drift Gas Pressures  

SciTech Connect

The ability of ion mobility spectrometry coupled with mass spectrometry (IMS-MS) to characterize biological mixtures has been illustrated over the past eight years. However, the challenges posed by the extreme complexity of many biological samples have demonstrated the need for higher resolution IMS-MS measurements. We have developed a higher resolution ESI-IMS-TOF MS by utilizing high pressure electrodynamic ion funnels at both ends of the IMS drift cell and operating the drift cell at an elevated pressure compared to a previous design. The ESI-IMS-TOF MS instrument consists of an ESI source, an hourglass ion funnel used for ion accumulation/injection into an 88 cm drift cell followed by a 10 cm ion funnel and a commercial orthogonal time-of-flight mass spectrometer providing high mass measurement accuracy. It was found that the rear (exit) ion funnel could be effectively operated as an extension of the drift cell when the DC fields were matched, allowing the instrument to have an effective drift region of 98 cm. Two differentially pumped quadrupole regions were used to couple the IMS and TOF MS to focus and minimize the ion transient time between the stages. The resolution of the instrument was evaluated at pressures ranging from 4 to12 Torr and ion mobility drift voltages of 16 V/cm (4 Torr) to 43 V/cm (12 Torr). An increase in resolution from 55 to 80 was observed from 4 to 12 Torr nitrogen drift gas with no loss in sensitivity. Given the increased usage of ion funnels prior to ion mobility separations, additional attention was directed towards the influence of drift gas on the observed ion populations trapped and transmitted using an electrodynamic ion funnel. The choice of drift gas was shown to influence the degree of ion heating and relative trapping efficiency within the ion funnel.

Baker, Erin Shammel; Clowers, Brian H.; Li, Fumin; Tang, Keqi; Tolmachev, Aleksey V.; Prior, David C.; Belov, Mikhail E.; Smith, Richard D.

2007-06-28

139

Evaluation of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Identification of Clinically Important Yeast Species ?  

PubMed Central

We evaluated the use of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the rapid identification of yeast species. Using Bruker Daltonics MALDI BioTyper software, we created a spectral database library with m/z ratios of 2,000 to 20,000 Da for 109 type and reference strains of yeast (44 species in 8 genera). The database was tested for accuracy by use of 194 clinical isolates (23 species in 6 genera). A total of 192 (99.0%) of the clinical isolates were identified accurately by MALDI-TOF MS. The MALDI-TOF MS-based method was found to be reproducible and accurate, with low consumable costs and minimal preparation time. PMID:20668126

Stevenson, Lindsay G.; Drake, Steven K.; Shea, Yvonne R.; Zelazny, Adrian M.; Murray, Patrick R.

2010-01-01

140

Matrix-assisted laser desorption ionization-time of flight mass spectrometry: a fundamental shift in the routine practice of clinical microbiology.  

PubMed

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; Wolk, Donna M

2013-07-01

141

GC-TOF/MS-based metabolomic profiling of estrogen deficiency-induced obesity in ovariectomized rats  

PubMed Central

Aim: To explore the alteration of endogenous metabolites and identify potential biomarkers using metabolomic profiling with gas chromatography coupled a time-of-flight mass analyzer (GC/TOF-MS) in a rat model of estrogen-deficiency-induced obesity. Methods: Twelve female Sprague-Dawley rats six month of age were either sham-operated or ovariectomized (OVX). Rat blood was collected, and serum was analyzed for biomarkers using standard colorimetric methods with commercial assay kits and a metabolomic approach with GC/TOF-MS. The data were analyzed using multivariate statistical techniques. Results: A high body weight and body mass index inversely correlated with serum estradiol (E2) in the OVX rats compared to the sham rats. Estrogen deficiency also significantly increased serum total cholesterol, triglycerides, and low-density lipoprotein cholesterol. Utilizing GC/TOF-MS-based metabolomic analysis and the partial least-squares discriminant analysis, the OVX samples were discriminated from the shams. Elevated levels of cholesterol, glycerol, glucose, arachidonic acid, glutamic acid, glycine, and cystine and reduced alanine levels were observed. Serum glucose metabolism, energy metabolism, lipid metabolism, and amino acid metabolism were involved in estrogen-deficiency-induced obesity in OVX rats. Conclusion: The series of potential biomarkers identified in the present study provided fingerprints of rat metabolomic changes during obesity and an overview of multiple metabolic pathways during the progression of obesity involving glucose metabolism, lipid metabolism, and amino acid metabolism. PMID:21293480

Ma, Bo; Zhang, Qi; Wang, Guang-ji; A, Ji-ye; Wu, Di; Liu, Ying; Cao, Bei; Liu, Lin-sheng; Hu, Ying-ying; Wang, Yong-lu; Zheng, Ya-ya

2011-01-01

142

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

143

The intact muscle lipid composition of bulls: an investigation by MALDI-TOF MS and 31P NMR.  

PubMed

The analysis of beef lipids is normally based on chromatographic techniques and/or gas chromatography in combination with mass spectrometry (GC/MS). Modern techniques of soft-ionization MS were so far scarcely used to investigate the intact lipids in muscle tissues of beef. The objective of the study was to investigate whether matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry and (31)P nuclear magnetic resonance (NMR) spectroscopy are useful tools to study the intact lipid composition of beef. For the MALDI-TOF MS and (31)P NMR investigations muscle samples were selected from a feeding experiment with German Simmental bulls fed different diets. Beside the triacylglycerols (TAGs), phosphatidylethanolamine (PE), phosphatidylcholine (PC) and phosphatidylinositol (PI) species the MALDI-TOF mass spectra of total muscle lipids gave also intense signals of cardiolipin (CL) species. The application of different matrix compounds, 2,5-dihydroxybenzoic acid (DHB) and 9-aminoacridine (9-AA), leads to completely different mass spectra: 9-AA is particularly useful for the detection of (polar) phospholipids, whereas apolar lipids, such as cholesterol and triacylglycerols, are exclusively detected if DHB is used. Finally, the quality of the negative ion mass spectra is much higher if 9-AA is used. PMID:19900429

Dannenberger, Dirk; Süss, Rosmarie; Teuber, Kristin; Fuchs, Beate; Nuernberg, Karin; Schiller, Jürgen

2010-02-01

144

Combined mass spectrometry-based metabolite profiling of different pigmented rice (Oryza sativa L.) seeds and correlation with antioxidant activities.  

PubMed

Nine varieties of pigmented rice (Oryza sativa L.) seeds that were black, red, or white were used to perform metabolite profiling by using ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and gas chromatography (GC) TOF-MS, to measure antioxidant activities. Clear grouping patterns determined by the color of the rice seeds were identified in principle component analysis (PCA) derived from UPLC-Q-TOF-MS. Cyanidin-3-glucoside, peonidin-3-glucoside, proanthocyanidin dimer, proanthocyanidin trimer, apigenin-6-C-glugosyl-8-C-arabiboside, tricin-O-rhamnoside-O-hexoside, and lipids were identified as significantly different secondary metabolites. In PCA score plots derived from GC-TOF-MS, Jakwangdo (JKD) and Ilpoom (IP) species were discriminated from the other rice seeds by PC1 and PC2. Valine, phenylalanine, adenosine, pyruvate, nicotinic acid, succinic acid, maleic acid, malonic acid, gluconic acid, xylose, fructose, glucose, maltose, and myo-inositol were significantly different primary metabolites in JKD species, while GABA, asparagine, xylitol, and sucrose were significantly distributed in IP species. Analysis of antioxidant activities revealed that black and red rice seeds had higher activity than white rice seeds. Cyanidin-3-glucoside, peonidin-3-glucoside, proanthocyanidin dimers, proanthocyanidin trimers, and catechin were highly correlated with antioxidant activities, and were more plentiful in black and red rice seeds. These results are expected to provide valuable information that could help improve and develop rice-breeding techniques. PMID:25268721

Kim, Ga Ryun; Jung, Eun Sung; Lee, Sarah; Lim, Sun-Hyung; Ha, Sun-Hwa; Lee, Choong Hwan

2014-01-01

145

Identification of filamentous fungi isolates by MALDI-TOF mass spectrometry: clinical evaluation of an extended reference spectra library.  

PubMed

The identification of filamentous fungi by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) relies mainly on a robust and extensive database of reference spectra. To this end, a large in-house library containing 760 strains and representing 472 species was built and evaluated on 390 clinical isolates by comparing MALDI-TOF MS with the classical identification method based on morphological observations. The use of MALDI-TOF MS resulted in the correct identification of 95.4% of the isolates at species level, without considering LogScore values. Taking into account the Brukers' cutoff value for reliability (LogScore >1.70), 85.6% of the isolates were correctly identified. For a number of isolates, microscopic identification was limited to the genus, resulting in only 61.5% of the isolates correctly identified at species level while the correctness reached 94.6% at genus level. Using this extended in-house database, MALDI-TOF MS thus appears superior to morphology in order to obtain a robust and accurate identification of filamentous fungi. A continuous extension of the library is however necessary to further improve its reliability. Indeed, 15 isolates were still not represented while an additional three isolates were not recognized, probably because of a lack of intraspecific variability of the corresponding species in the database. PMID:25349253

Becker, Pierre T; de Bel, Annelies; Martiny, Delphine; Ranque, Stéphane; Piarroux, Renaud; Cassagne, Carole; Detandt, Monique; Hendrickx, Marijke

2014-11-01

146

Maldi-tof mass spectrometry: any use for aspergilli?  

PubMed

Recently, relentless efforts to develop rapid, cost-effective, and reliable laboratory methods for daily diagnosis of fungal diseases such as aspergillosis appear to be materialized in the relatively new, but revolutionary matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS) technology. As for Aspergilli, MALDI-TOF MS profiling of isolates growing in culture-characteristic protein spectra are obtainable by means of simple and reproducible preanalytical and analytical procedures-ensures that single species within the different sections or complexes can be easily and accurately identified, including species that are morphologically and phylogenetically similar to each other. Thus, resort to longer and more onerous molecular biology techniques is restricted to those cases for which no spectra in the reference fungal database or library are available at the time of analysis. However, it is necessary to interrogate reference libraries composed of spectra that have been obtained using procedures similar to those used to obtain the test isolate's mass spectrum, as well as to continuously update these libraries for enriching them with fungal strains/species not (or not well) represented in their current versions. Compared to mold identification, very limited work was reported on the use of MALDI-TOF MS to perform strain typing or antifungal susceptibility testing for Aspergilli. If these complementing areas will be potentiated in the near future, MALDI-TOF MS could effectively support the clinical microbiology/mycology laboratory in its primary role of assisting either infection control specialists or physicians for the diagnosis and treatment of aspergillosis. PMID:25001870

Sanguinetti, Maurizio; Posteraro, Brunella

2014-12-01

147

The Effect of Culture Conditions on Microorganism Identification by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry  

SciTech Connect

Abstract Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been used to identify bacteria based upon protein signatures. This research shows that while some different proteins are produced by vegetative bacteria when they are cultured in different growth media, positive identification with MALDI-TOF MS is still possible with the protocol established at Pacific Northwest National Laboratory (PNNL)(11). A core set of small proteins remain constant under at least four different culture media conditions including minimal medium -M9, rich media - tryptic soy broth (TSB) or Luria-Bertani (LB) broth and blood agar plates such that analysis of the intact cells by matrix-assisted laser desorption/ionization mass spectrometry allows for consistent identification.

Valentine, Nancy B.; Wunschel, Sharon C.; Wunschel, David S.; Petersen, Catherine E.; Wahl, Karen L.

2005-01-01

148

Novel Mass Spectrometry-Based Tool for Genotypic Identification of Mycobacteria  

PubMed Central

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) after base-specific cleavage of PCR amplified and in vitro-transcribed 16S rRNA gene (rDNA) was used for the identification of mycobacteria. Full-length 16S rDNA reference sequences of 12 type strains of Mycobacterium spp. frequently isolated from clinical specimens were determined by PCR, cloning, and sequencing. For MALDI-TOF MS-based comparative sequence analysis, mycobacterial 16S rDNA signature sequences (?500 bp) of the 12 type strains and 24 clinical isolates were PCR amplified using RNA promoter-tagged forward primers. T7 RNA polymerase-mediated transcription of forward strands in the presence of 5-methyl ribo-CTP maximized mass differences of fragments generated by base-specific cleavage. In vitro transcripts were subsequently treated with RNase T1, resulting in G-specific cleavage. Sample analysis by MALDI-TOF MS showed a specific mass signal pattern for each of the 12 type strains, allowing unambiguous identification. All 24 clinical isolates were identified unequivocally by comparing their detected mass signal pattern to the reference sequence-derived in silico pattern of the type strains and to the in silico mass patterns of published 16S rDNA sequences. A 16S rDNA microheterogeneity of the Mycobacterium xenopi type strain (DSM 43995) was detected by MALDI-TOF MS and later confirmed by Sanger dideoxy sequencing. In conclusion, analysis of 16S rDNA amplicons by MS after base-specific cleavage of RNA transcripts allowed fast and reliable identification of the Mycobacterium tuberculosis complex and ubiquitous mycobacteria (mycobacteria other than tuberculosis). The technology delivers an open platform for high-throughput microbial identification on the basis of any specific genotypic marker region. PMID:14715774

Lefmann, Michael; Honisch, Christiane; Böcker, Sebastian; Storm, Niels; von Wintzingerode, Friedrich; Schlötelburg, Cord; Moter, Annette; van den Boom, Dirk; Göbel, Ulf B.

2004-01-01

149

Monitoring of peptide acylation inside degrading PLGA microspheres by capillary electrophoresis and MALDI-TOF mass spectrometry  

Microsoft Academic Search

The purpose of this research was to assess the acylation reactions of peptides, salmon calcitonin (sCT), human parathyroid hormone 1–34 (hPTH1–34) and leuprolide, in poly(lactic-co-glycolic acid) (PLGA) microspheres. Capillary electrophoresis (CE) and matrix-assisted laser desorption\\/ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used for determining and monitoring peptide acylation and quantitating acylation products in the degrading PLGA microspheres. In the degrading

Dong Hee Na; Yu Seok Youn; Sang Deuk Lee; Mi-Won Son; Won-Bae Kim; Patrick P. DeLuca; Kang Choon Lee

2003-01-01

150

Optimization of a direct analysis in real time\\/time-of-flight mass spectrometry method for rapid serum metabolomic fingerprinting  

Microsoft Academic Search

Metabolomic fingerprinting of bodily fluids can reveal the underlying causes of metabolic disorders associated with many diseases,\\u000a and has thus been recognized as a potential tool for disease diagnosis and prognosis following therapy. Here we report a rapid\\u000a approach in which direct analysis in real time (DART) coupled with time-of-flight (TOF) mass spectrometry (MS) and hybrid\\u000a quadrupole TOF (Q-TOF) MS

Manshui Zhou; John F. McDonald; Facundo M. Fernández

2010-01-01

151

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

152

Comparison of VITEK2, MALDI-TOF MS, and 16S rDNA sequencing for identification of Myroides odoratus and Myroides odoratimimus.  

PubMed

The genus Myroides comprises the 2 medically relevant species Myroides odoratus and Myroides odoratimimus that are rare opportunistic pathogens and cause infections in immunocompromised patients. A fast identification of Myroides is of importance because these bacterial strains show multiple resistance against antibiotics and therefore limit treatment options. They are associated, for instance, with urinary tract infections, sepsis, meningitis, pneumonia, and infectious cellulitis. Since more and more Myroides spp. are being described, additional potentially pathogenic bacteria may be identified in the future demanding the need for fast and reliable identification methods at species level. However, to date, only molecular approaches meet these demands. In this study, we, therefore, attempt to define an appropriate method other than DNA fingerprinting that will permit a comparable efficacy and, possibly, a more economical strain identification. For this purpose, we compared 2 widely used automated diagnostic systems (VITEK 2 [bioMérieux, Nürtingen, Germany] and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) [Bruker Daltonics, Bremen, Germany]) and correlated the results to 16S rDNA sequencing data. In total, we analyzed 22 strains collected in the course of routine diagnostics. In this study, we demonstrate that VITEK 2 reliably identifies the genus Myroides but cannot differentiate between M. odoratimimus and M. odoratus. In contrast to this, both MALDI-TOF MS and 16S rDNA sequencing efficiently distinguish between the 2 species. PMID:24666701

Schröttner, Percy; Rudolph, Wolfram W; Eing, Bodo R; Bertram, Sebastian; Gunzer, Florian

2014-06-01

153

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

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; Sanguinetti, Maurizio; Posteraro, Brunella

2014-05-01

154

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

155

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

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 Pra Netto Machado, L.; Tricot, A.; Benoit, F.; Treilles, M.; Bebear, C.

2013-01-01

157

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

158

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

159

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; Dormann, Peter

2011-01-01

160

MALDI-TOF mass spectrometry, an efficient technique for in situ detection and characterization of actinomycins.  

PubMed

An extensive study of actinomycins was performed using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). Actinomycins represent a well-known family of peptidolactone chromopeptides with potent cytostatic and antibiotic properties. Using five well-characterized streptomycete strains, we introduced MALDI-TOF MS as an efficient technique for rapid in situ detection of actinomycins in surface extracts of cells picked from agar plates. By this procedure, actinomycin complexes can be investigated with high sensitivity and accuracy in a minimum of time. These studies were complemented by mass spectrometric investigation of actinomycins obtained from culture filtrate extracts and purified by high-performance liquid chromatography to detect yet unknown actinomycin species. By feeding experiments, C-demethyl-actinomycins from Streptomyces chrysomallus and Streptomyces parvulus as well as hemi-actinomycins from Streptomyces antibioticus lacking one of the two pentapeptide lactone rings were isolated and characterized as novel variants for structure-activity relationship studies. Structural characterization of the investigated actinomycins was performed by post source decay MALDI-TOF MS. The specific features of the fragmentation patterns of the protonated and cationized forms of selected actinomycins were investigated in detail. PMID:24619547

Vater, Joachim; Crnov?i?, Ivana; Semsary, Siamak; Keller, Ullrich

2014-03-01

161

Derivatized mesoporous silica beads for MALDI-TOF MS profiling of human plasma and urine.  

PubMed

Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) is a promising tool for large-scale screening of body fluids for the early detection of human diseases. Proteins, peptides, and metabolites present in cells, tissues, or in body fluids constitute the molecular signatures of individuals. The design and generation of material-based platforms for capturing molecular signatures from body fluids has gained increasing interest in recent years. Highly selective materials are attractive candidates for a wide range of applications in biofluid proteomics. We have therefore developed a procedure based on mesoporous silica particles for the selective binding and enrichment of low molecular weight plasma/serum proteins by MALDI MS analysis ( Terracciano, R., Gaspari, M., Testa, F., Pasqua, L., Cuda G., Tagliaferri, P., Cheng, M. C., Nijdam, A. J., Petricoin, E. F., Liotta, L. A., Ferrari, M., and Venuta, S. ( 2006 ) Selective binding and enrichment for low-molecular weight biomarker molecules in human plasma after exposure to nanoporous silica particles . Proteomics 6, 3243-3250 ). Mesoporous silica beads (MSB) are able to harvest peptides from plasma and serum by means of nanosized porous channels with high surface area, while excluding large size proteins. Moreover, the absorption properties can be modified since the pore walls can be functionalized with different chemical species due to the high concentration of silanol groups at the surface. In this study, we performed derivatization of MSB with different functionalities, and we evaluated the derivatized materials for plasma and urine peptidomic profiling. Aminopropyl, N-(2-aminoethyl)-3-aminopropyl, and N,N,N' tris-carboxymethyl ethylene diamine, have been introduced onto the mesoporous silica surfaces in order to modulate selective peptide enrichment. We also explored various experimental conditions in order to optimize the performance of chemically modified MSB in the peptide profiling of human plasma and urine. These new derivatized mesoporous surfaces, in addition to the previous nonderivatized MSB, constitute an extended and reliable platform of five distinct chromatographic phases with defined surface functionality and porosity. Several plasma and urine peptides were extracted from derivatized MSB and then profiled by MALDI-TOF MS. The reproducibility of sample preparation by different functionalized beads was evaluated via three replicate analyses of plasma and urine samples. Lower coefficients of variation in the mass values and peak intensities resulted for plasma in comparison to those of urine samples; nevertheless, these where satisfactory for diagnostic purposes. For human urine, a linear correlation was found between spiked peptide concentrations and their peak areas (R(2) > 0.98) with a limit of detection in the low-nanogram per milliliter range, thus confirming the high sensitivity of the methodology, previously demonstrated for human plasma. Different panels of peptide repertoires have thus been collected from highly porous substrates chemically conjugated with different functional groups, and these may be used in biomarker discovery for disease diagnosis. PMID:19338374

Terracciano, Rosa; Pasqua, Luigi; Casadonte, Francesca; Frascà, Stella; Preianò, Mariaimmacolata; Falcone, Daniela; Savino, Rocco

2009-05-20

162

Identification of medically relevant species of arthroconidial yeasts by use of matrix-assisted laser desorption ionization-time of flight mass spectrometry.  

PubMed

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; Boekhout, Teun

2013-08-01

163

Multi-residue method for the analysis of 101 pesticides and their degradates in food and water samples by liquid chromatography\\/time-of-flight mass spectrometry  

Microsoft Academic Search

A comprehensive multi-residue method for the chromatographic separation and accurate mass identification of 101 pesticides and their degradation products using liquid chromatography\\/time-of-flight mass spectrometry (LC\\/TOF-MS) is reported here. Several classes of compounds belonging to different chemical families (triazines, organophosphorous, carbamates, phenylureas, neonicotinoids, etc.) were carefully chosen to cover a wide range of applications in the environmental field. Excellent chromatographic separation

Imma Ferrer; E. Michael Thurman

2007-01-01

164

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

165

Application of liquid chromatography/quadrupole-linear Ion trap mass spectrometry and time-of-flight mass spectrometry to the determination of pharmaceuticals and related contaminants in wastewater.  

PubMed

This paper describes an enhanced liquid chromatography-mass spectrometry (LC-MS) strategy for the analysis of a selected group of 56 organic pollutants in wastewater. This group comprises 38 pharmaceuticals and 10 of their most frequent metabolites, 6 pesticides, and 2 disinfectants. The LC-MS methodology applied is based in the use of a hybrid triple-quadrupole linear ion trap mass spectrometer (QTRAP) in combination with time-of-flight mass spectrometry (TOF-MS). The join application of both techniques provided very good results in terms of accurate quantification and unequivocal confirmation. Quantification was performed by LC-QTRAP-MS operating under selected reaction monitoring (SRM) mode in both positive and negative electrospray ionization. Unequivocal identification was provided by the acquisition of three SRM transitions per compound in most of the cases and by LC-TOF-MS analysis, which allows obtaining accurate mass measurements of the identified compounds with errors lower than 2 ppm. Additionally, the use of TOF-MS permits retrospective analysis, since the full spectrum is recorded at all times with a high sensitivity. Thus, review of recorded chromatograms looking for new compounds or transformation products suspected to be present in the samples is feasible allowing one to increase the scope of the method along the monitoring program. The analytical performance of the quantitative LC-QTRAP-MS method was evaluated in effluent wastewater samples. Linearity of response over 3 orders of magnitude was demonstrated for most compounds (R(2) > 0.99). Method limits of detection were between 0.04 and 50 ng L(-1). Finally, the methodology was successfully applied to a monitoring study intended to characterize wastewater effluents of six sewage treatment plants in Spain. The presence of most of compounds was detected at concentrations ranging from 9 ng L(-1) (atrazine) to 15 microg L(-1) (paraxanthine). PMID:18001124

Bueno, María Jesús Martínez; Agüera, Ana; Gómez, María José; Hernando, María Dolores; García-Reyes, Juan Francisco; Fernandez-Alba, Amadeo R

2007-12-15

166

RNase T1 mediated base-specific cleavage and MALDI-TOF MS for high-throughput comparative sequence analysis  

PubMed Central

Here we devise a new method for high-throughput comparative sequence analysis. The developed protocol comprises a homogeneous in vitro transcription/RNase cleavage system with the accuracy and data acquisition speed of matrix-assisted laser desorption/ionization coupled with time-of-flight mass spectrometry (MALDI-TOF MS). In summary, the target region is PCR amplified using primers tagged with promoter sequences of T7 or SP6 RNA polymerase. Using RNase T1, the in vitro transcripts are base-specifically cleaved at every G-position. This reaction results in a characteristic pattern of fragment masses that is indicative of the original target sequence. To enable high-throughput analysis, samples are processed with automated liquid handling devices and nanoliter amounts are dispensed onto SpectroCHIP arrays for reliable and homogeneous MALDI preparation. This system enables rapid automated comparative sequence analysis for PCR products up to 1 kb in length. We demonstrate the feasibility of the devised method for analysis of single nucleotide polymorphisms (SNPs) and pathogen identification. PMID:12711692

Hartmer, Ralf; Storm, Niels; Boecker, Sebastian; Rodi, Charles P.; Hillenkamp, Franz; Jurinke, Christian; van den Boom, Dirk

2003-01-01

167

Structural characterization of N-linked oligosaccharides on monoclonal antibody cetuximab by the combination of orthogonal matrix-assisted laser desorption\\/ionization hybrid quadrupole–quadrupole time-of-flight tandem mass spectrometry and sequential enzymatic digestion  

Microsoft Academic Search

Cetuximab is a novel therapeutic monoclonal antibody with two N-glycosylation sites: a conserved site in the CH2 domain and a second site within the framework 3 of the variable portion of the heavy chain. The detailed structures of these oligosaccharides were successfully characterized using orthogonal matrix-assisted laser desorption\\/ionization hybrid quadrupole–quadrupole time-of-flight mass spectrometry (oMALDI Qq–TOF MS) and tandem mass spectrometry

Jun Qian; Tun Liu; Li Yang; Ann Daus; Richard Crowley; Qinwei Zhou

2007-01-01

168

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

169

Detection of chemical weapon agents and simulants using chemical ionization reaction time-of-flight mass spectrometry.  

PubMed

Chemical ionization reaction time-of-flight mass spectrometry (CIR-TOF-MS) has been used for the analysis of prepared mixtures of chemical weapon agents (CWAs) sarin and sulfur mustard. Detection of the CWA simulants 2-chloroethyl ethyl sulfide, triethyl phosphate, and dimethyl methyl phosphonate has also been investigated. Chemical ionization of all the agents and simulants was shown to be possible using the CIR-TOF-MS technique with a variety of reagent ions, and the sensitivity was optimized by variation of instrument parameters. The ionization process was found to be largely unaffected by sample humidity levels, demonstrating the potential suitability of the method to a range of environmental conditions, including the analysis of CWAs in air and in the breath of exposed individuals. PMID:17894471

Cordell, Rebecca L; Willis, Kerry A; Wyche, Kevin P; Blake, Robert S; Ellis, Andrew M; Monks, Paul S

2007-11-01

170

Application of delayed extraction matrix-assisted laser desorption ionization time-of-flight mass spectrometry for analysis of sphingolipids in cultured skin fibroblasts from sphingolipidosis patients.  

PubMed

Sphingolipidoses are caused by defects of enzymes involved in the hydrolysis of sphingolipids. Using delayed extraction matrix-assisted laser desorption ionization time-of-flight mass spectrometry (DE MALDI-TOF-MS), we analyzed sphingolipids in cultured skin fibroblasts from patients with sphingolipidoses, including: (a) Farber disease (FD, acid ceramidase deficiency); (b) Gaucher disease (GD); (c) Niemann-Pick disease type C (NPDC); and (d) GM1-gangliosidosis (GM1G). Crude lipids were extracted from about 50 mg wet weight of cultured skin fibroblasts. After mild alkaline treatment, a sphingolipid fraction was prepared from the crude lipids and analyzed by DE MALDI-TOF-MS. The results were as follows: (a) in fibroblasts from the FD patient, the ceramide/sphingomyelin and ceramide/monohexosylceramide ratios were both significantly high; (b) in the GD patient, the glucosylceramide/sphingomyelin ratio was increased; on the other hand; (c) in the NPDC patient, the monohexosylceramide/sphingomyelin ratio was within normal range; and (d) in the GM1G patient, no specific data were obtained. Sphingolipids in cultured fibroblasts can be evaluated by DE MALDI-TOF-MS, whereas GM1-ganglioside or its asialo derivatives are not detectable. With this DE MALDI-TOF-MS method, ceramide or monohexosylceramide accumulating in cultured fibroblasts from cases of sphingolipidoses, such as FD and GD, respectively, can be easily detected. PMID:11934514

Fujiwaki, Takehisa; Yamaguchi, Seiji; Sukegawa, Kazuko; Taketomi, Tamotsu

2002-04-01

171

Matrix-Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) Mass Spectrometry for Detection of Antibiotic Resistance Mechanisms: from Research to Routine Diagnosis  

PubMed Central

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has been successfully applied as an identification procedure in clinical microbiology and has been widely used in routine laboratory practice because of its economical and diagnostic benefits. The range of applications of MALDI-TOF MS has been growing constantly, from rapid species identification to labor-intensive proteomic studies of bacterial physiology. The purpose of this review is to summarize the contribution of the studies already performed with MALDI-TOF MS concerning antibiotic resistance and to analyze future perspectives in this field. We believe that current research should continue in four main directions, including the detection of antibiotic modifications by degrading enzymes, the detection of resistance mechanism determinants through proteomic studies of multiresistant bacteria, and the analysis of modifications of target sites, such as ribosomal methylation. The quantification of antibiotics is suggested as a new approach to study influx and efflux in bacterial cells. The results of the presented studies demonstrate that MALDI-TOF MS is a relevant tool for the detection of antibiotic resistance and opens new avenues for both clinical and experimental microbiology. PMID:23297261

Chudackova, Eva; Walkova, Radka

2013-01-01

172

Identification of pathogens from blood culture bottles in spiked and clinical samples using matrix-assisted laser desorption ionization time-of-flight mass-spectrometry analysis  

PubMed Central

Background Blood stream infections significantly contribute to mortality. An early most appropriate antimicrobial therapy is crucial for a favourable outcome of the patient. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) may speed up the diagnostic of causative micro organisms. Findings MALDI-TOF MS using the SARAMIS database was applied to 37 spiked blood culture samples. Identification rates of spiked samples were as follows: The species level was determined in 16 of 21 (76.2%) Gram negative bacteria and in 11 of 13 (84.6%) Gram positive bacteria. Genus level only was determined in additional 2 Gram negative and for the 2 Gram positive strains. Yeast species could not be identified. MALDI-TOF MS was also compared to cultured-based results in standard routine diagnostic. Identification rates of patient samples were as follows: The species level was determined in 41 of 47 (87.2%) Gram negative bacteria and in 63 of 123 (51.2%) Gram positive bacteria. Genus level only was determined in additional 2 Gram negative bacteria. Once again no yeasts were identified. A prolonged incubation of BC bottles for 16 hours after primary positive alert did not influence the concentration of bacteria and identification rates. Conclusions The SARAMIS database used in our experiments mainly confirms previous findings that were obtained with the MALDI-TOF MS BRUKER system by others. PMID:24972877

2014-01-01

173

Two classifiers based on serum peptide pattern for prediction of HBV-induced liver cirrhosis using MALDI-TOF MS.  

PubMed

Chronic infection with hepatitis B virus (HBV) is associated with the majority of cases of liver cirrhosis (LC) in China. Although liver biopsy is the reference method for evaluation of cirrhosis, it is an invasive procedure with inherent risk. The aim of this study is to discover novel noninvasive specific serum biomarkers for the diagnosis of HBV-induced LC. We performed bead fractionation/MALDI-TOF MS analysis on sera from patients with LC. Thirteen feature peaks which had optimal discriminatory performance were obtained by using support-vector-machine-(SVM-) based strategy. Based on the previous results, five supervised machine learning methods were employed to construct classifiers that discriminated proteomic spectra of patients with HBV-induced LC from those of controls. Here, we describe two novel methods for prediction of HBV-induced LC, termed LC-NB and LC-MLP, respectively. We obtained a sensitivity of 90.9%, a specificity of 94.9%, and overall accuracy of 93.8% on an independent test set. Comparisons with the existing methods showed that LC-NB and LC-MLP held better accuracy. Our study suggests that potential serum biomarkers can be determined for discriminating LC and non-LC cohorts by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. These two classifiers could be used for clinical practice in HBV-induced LC assessment. PMID:23509784

Cao, Yuan; He, Kun; Cheng, Ming; Si, Hai-Yan; Zhang, He-Lin; Song, Wei; Li, Ai-Ling; Hu, Cheng-Jin; Wang, Na

2013-01-01

174

Metabonomic analysis of the toxic effects of TM208 in rat urine by HPLC-ESI-IT-TOF/MS.  

PubMed

4-Methylpiperazine-1-carbodithiocacid-3-cyano-3,3-diphenylpropyl ester hydrochloride (TM208) was a potential antitumor new drug with many preliminary studies in pharmacokinetics and pharmacodynamics. This study aims to determine whether TM208 elicits toxic effects by metabonomics for the first time. Sprague Dawley (SD) rats were exposured to TM208 at a single therapeutic dose (100mg/kg/d) for 5 days, metabolites of urine samples from both control and TM208-treated groups were analyzed using high performance liquid chromatography-electrospray ionization source in combination with hybrid ion trap and high-resolution time-of-flight mass spectrometry (HPLC-ESI-IT-TOF/MS). Metabolites such as aminoadipic acid, creatine, gluconic acid, cis-aconitic acid, succinic acid and pipecolic acid which changed significantly, were identified as potential biomarkers. These results suggest that the changes in urinary metabolites of rats after exposure to TM208 were mainly related to energy metabolism and amino acid metabolism, which may be helpful to further understand the mechanism of TM208 toxicity in rats and a new drug development. PMID:24747524

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

2014-05-15

175

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

176

Analysis of roasted and unroasted Pistacia terebinthus volatiles using direct thermal desorption-GCxGC-TOF/MS.  

PubMed

The objective of this study was to determine the effects of roasting time on volatile components of Pistacia terebinthus L., a fruit growing wild in Turkey. The whole fruit samples were pan roasted for 0, 5, 10, 15, 20 and 25min at 200°C. Volatile compounds were isolated and identified using the direct thermal desorption (DTD) method coupled with comprehensive gas chromatography - time of flight mass spectrometry (GCxGC-TOF/MS). The major components of the fresh hull of P. terebinthus were ?-pinene (10.37%), limonene (8.93%), ?-pinene (5.53%), 2-carene (4.47%) and ?-muurolene (4.29%). Eighty-three constituents were characterised from the volatiles of fresh whole P. terebinthus fruits obtained by direct thermal desorption with ?-pinene (9.62%), limonene (5.54%), ?-cadinane (5.48%), ?-pinene (5.46%), ?-caryophyllene (5.24%) being the major constituents. The type and the number of constituents characterised were observed to change with differing roasting times. Limonene (5.56%), ?-pinene (4.84%), 5-methylfurfural (4.78%), 5-hydroxymethylfurfural (5-HMF, 3.89%), dimethylmetoxyfuranone (3.67%) and 3-methyl-2(5H)furanone (3.12%) were identified as the major components among the 104 compounds characterised in the volatiles of P. terebinthus, roasted for 25min. In addition, volatiles of fully roasted P. terebinthus fruits contained furans and furanones (15.42%), pyridines (4.45%) and benzene derivatives (3.81%) as the major groups. PMID:25212365

Gogus, F; Ozel, M Z; Kocak, D; Hamilton, J F; Lewis, A C

2011-12-01

177

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

178

The potential of using laser ablation inductively coupled plasma time of flight mass spectrometry (LA-ICP-TOF-MS) in the forensic analysis of micro debris  

Microsoft Academic Search

The majority of crimes result in the generation of some form of physical evidence, which is available for collection by crime scene investigators or police. However, this debris is often limited in amount as modern criminals become more aware of its potential value to forensic scientists. The requirement to obtain robust evidence from increasingly smaller sized samples has required refinement

Cameron J. Scadding; R. John Watling; Allen G. Thomas

2005-01-01

179

On-Line Screening and Identification of Radical Scavenging Compounds Extracted from Flos Lonicerae by LC-DAD–TOF-MS  

Microsoft Academic Search

Flos Lonicerae is commonly used in traditional Chinese medicine. The ethanolic extracts prepared from Flos Lonicerae were used for the rapid evaluation of free radical scavenging activity by using the extracts to clear on-line 2,2?-diphenyl-1-picrylhydrazyl\\u000a (DPPH·) free radical with LC serving as the separating tool of bioactive compounds, two diode array detectors (DAD) and a\\u000a time-of-flight mass spectrometer (TOF-MS) as

Yan Chen; Shaoguang Li; Xinhua Lin; Hongbin Luo; Guangwen Li; Hong Yao

2008-01-01

180

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

181

Potential of MALDI-TOF mass spectrometry as a rapid detection technique in plant pathology: identification of plant-associated microorganisms.  

PubMed

Plant diseases caused by plant pathogens substantially reduce crop production every year, resulting in massive economic losses throughout the world. Accurate detection and identification of plant pathogens is fundamental to plant pathogen diagnostics and, thus, plant disease management. Diagnostics and disease-management strategies require techniques to enable simultaneous detection and quantification of a wide range of pathogenic and non-pathogenic microorganisms. Over the past decade, rapid development of matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) techniques for characterization of microorganisms has enabled substantially improved detection and identification of microorganisms. In the biological sciences, MALDI-TOF MS is used to analyze specific peptides or proteins directly desorbed from intact bacteria, fungal spores, nematodes, and other microorganisms. The ability to record biomarker ions, in a broad m/z range, which are unique to and representative of individual microorganisms, forms the basis of taxonomic identification of microorganisms by MALDI-TOF MS. Recent advances in mass spectrometry have initiated new research, i.e. analysis of more complex microbial communities. Such studies are just beginning but have great potential for elucidation not only of the interactions between microorganisms and their host plants but also those among different microbial taxa living in association with plants. There has been a recent effort by the mass spectrometry community to make data from large scale mass spectrometry experiments publicly available in the form of a centralized repository. Such a resource could enable the use of MALDI-TOF MS as a universal technique for detection of plant pathogens and non-pathogens. The effects of experimental conditions are sufficiently understood, reproducible spectra can be obtained from computational database search, and microorganisms can be rapidly characterized by genus, species, or strain. PMID:22644150

Ahmad, Faheem; Babalola, Olubukola O; Tak, Hamid I

2012-09-01

182

Application of matrix-assisted laser desorption\\/ionization time-of-flight mass spectrometry for monitoring the digestion of phosphatidylcholine by pancreatic phospholipase A 2  

Microsoft Academic Search

Different methods were established for monitoring the phospholipase A2(PLA2) activity but all of them are rather cumbersome and time consuming. In this paper we have investigated the suitability of matrix-assisted laser desorption\\/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the determination of the PLA2 activity. Phosphatidylcholine (PC) was digested with pancreatic PLA2 under different conditions, i.e., various Ca2+, PC, and PLA2

Marijana Petkovi?; Julia Müller; Matthias Müller; Jürgen Schiller; Klaus Arnold; Jürgen Arnhold

2002-01-01

183

Detection of specific DNA from crude extracts of rice seed grains using matrix-assisted laser desorption ionization time-of-flight mass spectrometry  

Microsoft Academic Search

To rapidly detect specific genes, crude extracts prepared from rice seed grains were used as templates for PCR, the PCR products were digested with restriction enzymes or urasil-DNA glycosylase, and then matrix-assisted laser desorption ionization mass spectrometry (MALDI-TOF MS) was used to detect amplified DNA. It was possible to amplify small DNA fragments (50–60bp), but not large ones (>200bp), using

Hideyuki Kajiwara

2011-01-01

184

Standardized Approach to Proteome Profiling of Human Serum Based on Magnetic Bead Separation and Matrix-Assisted Laser Desorption\\/Ionization Time-of-Flight Mass Spectrometry  

Microsoft Academic Search

Background: Magnetic bead purification for the analy- sis of low-abundance proteins in body fluids facilitates the identification of potential new biomarkers with matrix-assisted laser desorption\\/ionization time-of- flight mass spectrometry (MALDI-TOF MS). The aim of our study was to establish a proteome fractionation technique and to validate a standardized blood sam- pling, processing, and storage procedure for proteomic pattern analysis. Methods:

Sven Baumann; Uta Ceglarek; Georg Martin Fiedler; Jan Lembcke; Alexander Leichtle; Joachim Thiery

2005-01-01

185

Profiling of rat plasma by surface-enhanced laser desorption\\/ionization time-of-flight mass spectrometry, a novel tool for biomarker discovery in nutrition research  

Microsoft Academic Search

The recent development of high-throughput proteomic technologies has given us new methods to analyze how an organism responds to changes in its nutritional environment. The analysis of plasma samples by surface-enhanced laser desorption\\/ionization time-of-flight mass spectrometry (SELDI–TOF–MS) was investigated as a novel approach to the identification of new biomarkers of nutrient status. Pre-fractionation of rat plasma by anion-exchange chromatography in

Thomas Linke; A. Catharine Ross; Earl H Harrison

2004-01-01

186

Iron interference on matrix-assisted laser desorption\\/ionisation time-of-flight mass spectra of condensed tannins  

Microsoft Academic Search

Matrix-assisted laser desorption\\/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) was used to reveal the influence of iron on the detectability of condensed tannins extracted from Picea abies. Iron chloride mixed with condensed tannins suppresses the detection of tannins by MALDI-TOF MS in a dose-dependent manner. Total suppression is observed at concentrations of 250 and 500 mg FeCl 3 g –1 of sample. At

Clemens J. Engelke; Heike Knicker; Ingrid Kögel-Knabner

2004-01-01

187

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

188

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

189

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.; Muller, E.; Horre, R.; Maier, T.; Wenzel, T.; Kostrzewa, M.; Bierbaum, G.; Hoerauf, A.; Sahl, H.-G.

2009-01-01

190

Chip-based nLC-TOF-MS is a highly stable technology for large-scale high-throughput analyses.  

PubMed

Many studies focused on the discovery of novel biomarkers for the diagnosis and treatment of disease states are facilitated by mass spectrometry-based technology. HPLC coupled to mass spectrometry is widely used; miniaturization of this technique using nano-liquid chromatography (LC)-mass spectrometry (MS) usually results in better sensitivity, but is associated with limited repeatability. The recent introduction of chip-based technology has significantly improved the stability of nano-LC-MS, but no substantial studies to verify this have been performed. To evaluate the temporal repeatability of chip-based nano-LC-MS analyses, N-glycans released from a serum sample were repeatedly analyzed using nLC-PGC-chip-TOF-MS on three non-consecutive days. With an average inter-day coefficient of variation of 4 %, determined on log10-transformed integrals, the repeatability of the system is very high. Overall, chip-based nano-LC-MS appears to be a highly stable technology, which is suitable for the profiling of large numbers of clinical samples for biomarker discovery. PMID:23525540

Ruhaak, L Renee; Taylor, Sandra L; Miyamoto, Suzanne; Kelly, Karen; Leiserowitz, Gary S; Gandara, David; Lebrilla, Carlito B; Kim, Kyoungmi

2013-05-01

191

Combination of UHPLC/Q-TOF-MS, NMR spectroscopy, and ECD calculation for screening and identification of reactive metabolites of gentiopicroside in humans.  

PubMed

The metabolic investigation of natural products is a great challenge because of unpredictable metabolic pathways, little knowledge on metabolic effects, and lack of recommended analytical methodology. Herein, a combined strategy based on ultrahigh-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC/Q-TOF-MS), nuclear magnetic resonance (NMR) spectroscopy, and electronic circular dichroism (ECD) calculation was developed and employed for the human metabolism study of gentiopicroside (GPS), a naturally hepato-protective iridoid glycoside. The whole metabolic study consisted of three major procedures. First, an improved UHPLC/Q-TOF-MS method was used to separate and detect a total of 15 GPS metabolites that were obtained from urine samples (0 to 72 h) of 12 healthy male participants after a single 50-mg oral dose of GPS. Second, a developed "MS-NMR-MS" method was applied to accurately identify molecular structures of the observed metabolites. Finally, given that the associated stereochemistry may be a crucial factor of the metabolic activation, the absolute configuration of the reactive metabolites was revealed through chemical calculations. Based on the combined use, a pair of diastereoisomers (G05 and G06) were experimentally addressed as the bioreactive metabolites of GPS, and the stereochemical determination was completed. Whereas several novel metabolic transformations, occurring via oxidation, N-heterocyclization and glucuronidation after deglycosylation, were also observed. The results indicated that GPS has to undergo in vivo metabolism-based activation to generate reactive molecules capable of processing its hepato-protective activity. PMID:24408300

Han, Han; Xiong, Ai-Zhen; He, Chun-Yong; Liu, Qing; Yang, Li; Wang, Zheng-Tao

2014-02-01

192

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

193

Structural changes of ultrasonicated bovine serum albumin revealed by hydrogen-deuterium exchange and mass spectrometry.  

PubMed

The structural changes of bovine serum albumin (BSA) under high-intensity ultrasonication were investigated by fluorescence spectroscopy and mass spectrometry. Evidence for the ultrasonication-induced conformational changes of BSA was provided by the intensity changes and maximum-wavelength shift in fluorescence spectrometry. Matrix-assisted laser desorption-ionization time-of-flight mass spectroscopy (MALDI-TOF MS) revealed the increased intensity of the peak at the charge state +5 and a newly emerged peak at charge state +6, indicating that the protein became unfolded after ultrasonication. Prevalent unfolding of BSA after ultrasonication was revealed by hydrogen-deuterium exchange coupled with mass spectrometry (HDX-MS). Increased intensity and duration of ultrasonication further promoted the unfolding of the protein. The unfolding induced by ultrasonication goes through an intermediate state similar to that induced by a low concentration of denaturant. PMID:25224638

Zhang, Qiuting; Tu, Zongcai; Wang, Hui; Huang, Xiaoqin; Sha, Xiaomei; Xiao, Hui

2014-11-01

194

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

195

Elemental, Isotopic, and Organic Analysis on Mars with Laser TOF-MS  

NASA Astrophysics Data System (ADS)

The in-depth landed exploration of Mars will require increasingly sophisticated robotic analytical tools for both in situ composition science [1] and reconnaissance for sample return [2]. Beyond dust, rock surfaces, and topsoil, samples must be accessed within rocks and ice, well below surface soil, and possibly in elevated deposit layers. A range of spatial scales will be studied, and for the most information-rich microscopic analyses, samples must be acquired, prepared, and positioned with high precision. In some cases samples must also be brought into a vacuum chamber. After expending such resources, it will be important to apply techniques that provide a wide range of information about the samples. Microscopy, mineralogy, and molecular/organic, elemental, and isotopic analyses are all needed, at a minimum, to begin to address the in situ goals at Mars. These techniques must work as an efficient suite to provide layers of data, each layer helping to determine if further analysis on a given sample is desired. In the spirit of broad-band and efficient data collection, we are developing miniature laser time-of-flight mass spectrometers (TOF-MS) for elemental, isotopic, and molecular/organic microanalysis of unprepared solid samples. Laser TOF-MS uses a pulsed laser to volatilize and ionize material from a small region on the sample. The laser energy and focus can be adjusted for atomic and molecular content, sampling area, and depth. Ions travel through the instrument and are detected at a sequence of times proportional to the square root of their mass-to- charge ratios. Thus, each laser pulse produces a complete mass spectrum (in less than 50 microseconds). These instruments can now be significantly miniaturized (potentially to the size of a soda can) without a loss in performance. This effort is reviewed here with an emphasis on applications to Mars exploration.

Brinckerhoff, W. B.; Cornish, T. J.

2000-07-01

196

Elemental, Isotopic, and Organic Analysis on Mars with Laser TOF-MS  

NASA Technical Reports Server (NTRS)

The in-depth landed exploration of Mars will require increasingly sophisticated robotic analytical tools for both in situ composition science [1] and reconnaissance for sample return [2]. Beyond dust, rock surfaces, and topsoil, samples must be accessed within rocks and ice, well below surface soil, and possibly in elevated deposit layers. A range of spatial scales will be studied, and for the most information-rich microscopic analyses, samples must be acquired, prepared, and positioned with high precision. In some cases samples must also be brought into a vacuum chamber. After expending such resources, it will be important to apply techniques that provide a wide range of information about the samples. Microscopy, mineralogy, and molecular/organic, elemental, and isotopic analyses are all needed, at a minimum, to begin to address the in situ goals at Mars. These techniques must work as an efficient suite to provide layers of data, each layer helping to determine if further analysis on a given sample is desired. In the spirit of broad-band and efficient data collection, we are developing miniature laser time-of-flight mass spectrometers (TOF-MS) for elemental, isotopic, and molecular/organic microanalysis of unprepared solid samples. Laser TOF-MS uses a pulsed laser to volatilize and ionize material from a small region on the sample. The laser energy and focus can be adjusted for atomic and molecular content, sampling area, and depth. Ions travel through the instrument and are detected at a sequence of times proportional to the square root of their mass-to- charge ratios. Thus, each laser pulse produces a complete mass spectrum (in less than 50 microseconds). These instruments can now be significantly miniaturized (potentially to the size of a soda can) without a loss in performance. This effort is reviewed here with an emphasis on applications to Mars exploration.

Brinckerhoff, W. B.; Cornish, T. J.

2000-01-01

197

Updating the taxonomic toolbox: classification of Alteromonas spp. using multilocus phylogenetic analysis and MALDI-TOF mass spectrometry.  

PubMed

Bacteria of the genus Alteromonas are Gram-negative, strictly aerobic, motile, heterotrophic marine bacteria known for their versatile metabolic activities. Identification and classification of novel species belonging to the genus Alteromonas generally involves DNA-DNA hybridization (DDH) as distinct species often fail to be resolved at the 97 % threshold value of the 16S rRNA gene sequence similarity. In this study, the applicability of Multilocus Phylogenetic Analysis (MLPA) and Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) for the differentiation of Alteromonas species has been evaluated. Phylogenetic analysis incorporating five house-keeping genes (dnaK, sucC, rpoB, gyrB, and rpoD) revealed a threshold value of 98.9 % that could be considered as the species cut-off value for the delineation of Alteromonas spp. MALDI-TOF MS data analysis reconfirmed the Alteromonas species clustering. MLPA and MALDI-TOF MS both generated data that were comparable to that of the 16S rRNA gene sequence analysis and may be considered as useful complementary techniques for the description of new Alteromonas species. PMID:22965754

Ng, Hooi Jun; Webb, Hayden K; Crawford, Russell J; Malherbe, François; Butt, Henry; Knight, Rachel; Mikhailov, Valery V; Ivanova, Elena P

2013-02-01

198

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

199

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

200

Matrix-assisted laser desorption ionisation-time of flight mass spectrometry for rapid identification of Laribacter hongkongensis.  

PubMed

Laribacter hongkongensis is a Gram-negative, facultative anaerobic, motile, S-shaped, urease-positive bacillus associated with invasive infections in liver cirrhosis patients and community-acquired gastroenteritis. Most cases of L hongkongensis infections occur in eastern countries. Information is lacking on the usefulness of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of bacteria important in eastern countries. Using the Bruker database extended with 21 L hongkongensis reference strains, all 240 L hongkongensis isolates recovered from patients, fish, frogs and water were correctly identified, with 224 (93.3%) strains having top match scores ?2.0. Notably, the strain of Chromobacterium violaceum was not reliably identified although it is included in the database. MALDI-TOF MS is useful for the accurate routine identification of L hongkongensis after adding reference L hongkongensis main spectra to the database. The number of strains for each species in MALDI-TOF MS databases should be expanded to cover intraspecies variability. PMID:23814260

Tang, Bone S F; Lau, Susanna K P; Teng, Jade L L; Chan, Tsz-Ming; Chan, Wai-Sing; Wong, Ting-Yin; Tong, Yu-Ting; Fan, Rachel Y Y; Yuen, Kwok-Yung; Woo, Patrick C Y

2013-12-01

201

Identification of Plesiomonas spp.: serological and MALDI-TOF MS methods.  

PubMed

Biochemical and serological profiles of isolates of Plesiomonas shigelloides were assayed using standard procedures in isolates from various clinical samples. Seventy-four isolates, including P. shigelloides type strain, were further characterized by MALDI-TOF MS using 3-methoxy-4-hydroxycinnamic acid as matrix. Multiple ions in the 3- to 12-kDa mass range were found in the spectra of each strain, from which the "species-identifying" unique biomarker ions were identified. After creating the species-specific patterns, a spectral database was generated for reliable, rapid, reproducible and accurate identification of Plesiomonas strains. The classical strain description (biochemical and serological) was thus complemented with the metabolic (proteomic) characterization. PMID:21253918

Kolínská, R; D?evínek, M; Aldová, E; Zemli?ková, H

2010-11-01

202

Molecular diversity of cereulide detected by means of nano-HPLC-ESI-Q-TOF-MS  

NASA Astrophysics Data System (ADS)

Cereulide is a cyclic dodecadepsipeptide from a pathogenic bacteria Bacillus cereus, which shows the emetic toxicity. Molecular diversity, or variety in homologation was found as a minor constituent of this cyclic peptide. Its molecular weight is 1152 but its homologs were observed as 1138 and 1166, which had 14 mass lower and higher differences from cereulide. This homologation was observed in about 10% of cereulide. It seemed to be difficult to determine the heterogeneous amino acids directly by MS/MS analysis on the intact molecules of cereulide. And hydrolysis of this cyclic peptide gave dipeptides, which were analyzed to determine their heterogeneous components by means of nano-HPLC-ESI-Q-TOF-MS and MS/MS. Among all amino- and oxy-acids, we found that O-Val and O-Leu were the keys of variation in cereulide. These findings will be significant to establish an identification method for pathogenic bacteria on the basis of biosynthetic pathways.

Pitchayawasin, Suthasinee; Isobe, Minoru; Kuse, Masaki; Franz, Thomas; Agata, Norio; Ohta, Michio

2004-07-01

203

False results caused by solvent impurity in tetrahydrofuran for MALDI TOF MS analysis of amines.  

PubMed

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. PMID:24222486

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

2014-02-01

204

Gas Chromatography -Mass Spectrometry  

E-print Network

GCMS - 1 Gas Chromatography - Mass Spectrometry GC-MS ANALYSIS OF ETHANOL AND BENZENE IN GASOLINE Last updated: June 17, 2014 #12;GCMS - 2 Gas Chromatography - Mass Spectrometry GC-MS ANALYSIS). The goal of this experiment is to separate the components in a sample of gasoline using Gas Chromatography

Nizkorodov, Sergey

205

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

206

Analysis of Hanford-related Organics using Matrix-assisted Laser Desorption Ionization Time-of-flight Mass Spectrometry  

SciTech Connect

Matrix-assisted laser desorption/ionization coupled with time-of-flight mass spectrometry (MALDI/TOF-MS) was used for the analysis of low-molecular phosphate compounds found in Hanford tank wastes. The mass spectra of these compounds indicate protonated peaks as well as sodium adducts. Analytical methods presently utilized for the analysis of the phosphate-related organics are both time consuming and labor intensive. A promising alternative is MALDI/TOFMS. The MALDI process produces both positive and negative ions directly and very little sample is required. In addition,there is limited sample preparation and minimal hazardous waste production.

Campbell, James A.(BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB); Hess, Wayne P.(BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB); Lohman, Jeremy R.(ASSOC WESTERN UNIVERSITY) [ASSOC WESTERN UNIVERSITY; Goheen, Steven C.(BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB)

2001-01-01

207

"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

208

Selective determination of 2,4-xylenol by gas chromatography/supersonic jet/resonance-enhanced multiphoton ionization/time-of-flight mass spectrometry.  

PubMed

Gas chromatography/supersonic jet/resonance-enhanced multiphoton ionization/time-of-flight mass spectrometry (GC/SSJ/REMPI/TOF-MS) was employed for isomer-selective determination of 2,4-xylenol in river and seawater samples. The sample containing 2,4-xylenol was measured using argon, rather than helium, as the GC carrier gas to cool the analyte molecule sufficiently. The instrumental detection limit (IDL) achieved at a flow rate of 1 mLmin(-1) was 14 pg. Although this value was comparable to the value (ca. 10 pg) obtained by gas chromatography/electron impact/quadrupole mass spectrometry (GC/EI/QMS). When the flow rate was increased to 8 mLmin(-1), interference from the 2,5-xylenol isomer was completely suppressed. The IDL was degraded to 83 or 160 pg at a flow rate of 5 or 8 mLmin(-1), respectively. The recovery of 2,4-xylenol from the river and the seawater samples was 85 and 93%, respectively. The time for analysis was only 10 min per one sample in GC/SSJ/REMPI/TOF-MS. These results suggest that GC/SSJ/REMPI/TOF-MS is useful for the selective measurement of 2,4-xylenol, which has been designated a Class I chemical substance in the Pollutant Release and Transfer Register (PRTR). PMID:21056717

Tsukatani, Hiroko; Okudaira, Hiroki; Shitamichi, Osamu; Uchimura, Tomohiro; Imasaka, Totaro

2010-12-01

209

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

210

Typing of nitrogen-fixing Frankia strains by matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry.  

PubMed

Matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS) was evaluated as a technique to characterize strains of the nitrogen-fixing actinomycete Frankia. MALDI-TOF MS reliably distinguished 37 isolates within the genus Frankia and assigned them to their respective host infection groups, i.e., the Alnus/Casuarina and the Elaeagnus host infection groups. The assignment of individual strains to sub-groups within the respective host infection groups was consistent with classification based on comparative sequence analysis of nifH gene fragments, confirming the usefulness of MALDI-TOF MS as a rapid and reliable tool for the characterization of Frankia strains. PMID:21242047

Hahn, Dittmar; Mirza, Babur; Benagli, Cinzia; Vogel, Guido; Tonolla, Mauro

2011-02-01

211

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

212

Rapid identification of Gram-negative organisms from blood culture bottles using a modified extraction method and MALDI-TOF mass spectrometry.  

PubMed

The application of matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry (MS) directly to blood culture broth has potential to identify bloodstream infection earlier and facilitate timely management. We prospectively tested a novel, rapid, and inexpensive in-house spin-lysis protocol with formic acid extraction and compared MALDI-TOF MS identification of Gram-negative bacteria with traditional phenotypic methods (Phoenix™) directly from 318 BACTEC™ (Becton Dickinson, Franklin Lakes, USA) blood cultures. The MS score was ?1.7 in 268 (91.8%) monomicrobial broths, with concordance to genus and species level of 100% and 97.0%, respectively. MALDI-TOF MS still has limited capacity to detect all species in polymicrobial broths. PMID:23891220

Gray, Timothy J; Thomas, Lee; Olma, Tom; Iredell, Jonathan R; Chen, Sharon C-A

2013-10-01

213

Differentiation of vanA-positive Enterococcus faecium from vanA-negative E. faecium by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry.  

PubMed

Vancomycin-resistant enterococci are important nosocomial pathogens that require rapid and accurate detection for infection control. Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS) has begun to be used in many clinical laboratories because it is a rapid, simple and inexpensive method for identifying micro-organisms. In this study, the performance of MALDI-TOF/MS to differentiate vanA-positive Enterococcus faecium (VPEF) from vanA-negative E. faecium (VNEF) was evaluated. A total of 61 VPEF isolates collected during regional surveillance in Kyoto (Japan) and 71 VNEF isolates collected from bacteraemia patients were analysed using MALDI-TOF/MS with three ClinProTools models. All of the isolates were correctly identified as E. faecium using the MALDI Biotyper system. To discriminate between VPEF and VNEF, all three ClinProTools models yielded >90% recognition capability (basic sensitivity) and cross-validation (reliability of the models); the genetic algorithm model exhibited the highest performance (99.18% and 92.40%, respectively). The high detection performance of MALDI-TOF/MS for VPEF offers the potential for routine laboratory use. PMID:25104134

Nakano, Satoshi; Matsumura, Yasufumi; Kato, Karin; Yunoki, Tomoyuki; Hotta, Go; Noguchi, Taro; Yamamoto, Masaki; Nagao, Miki; Ito, Yutaka; Takakura, Shunji; Ichiyama, Satoshi

2014-09-01

214

An activity-integrated strategy involving ultra-high-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry and fraction collector for rapid screening and characterization of the ?-glucosidase inhibitors in Coptis chinensis Franch. (Huanglian).  

PubMed

An activity integrated strategy was established and validated to screen ?-glucosidase inhibitors by ultra-high-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry and fraction collector (UHPLC/Q-TOF-MS-FC). UHPLC was used to separate the components in Coptis chinensis Franch. (Huanglian in Chinese) extract, which was identified by UHPLC-Q-TOF-MS to acquire structural information and collected by the fraction collector. Finally, the collected fractions were tested for inhibitory activity of ?-glucosidase. The results showed that Huanglian extract had the ?-glucosidase inhibitory activity with the IC50 value at 3.528mgmL(-1), which could be used for the treatment of diabetes. Alkaloids were the main components that had inhibitory activity of ?-glucosidase in Huanglian extract, while the inhibitory activity of phenolic acids against ?-glucosidase was relatively weaker. Coptisine, epiberberine, jatrorrhizin and berberine were screened and identified as ?-glucosidase inhibitors from Huanglian extract in vitro. Compared with conventional methods, the integrated UHPLC/Q-TOF-MS-FC method could quantitatively analyze ?-glucosidase inhibitory activity of individual constituent and provide the total ?-glucosidase inhibitory activity of the samples. The results demonstrated that the activity integrated UHPLC/Q-TOF-MS-FC method was an effective and powerful tool for screening and identifying active ingredients from Traditional Chinese medicines. PMID:25137652

Ge, Ai-Hua; Bai, Yang; Li, Jin; Liu, Jiao; He, Jun; Liu, Er-Wei; Zhang, Peng; Zhang, Bo-Li; Gao, Xiu-Mei; Chang, Yan-Xu

2014-11-01

215

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

216

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

217

Fourier Transform Mass Spectrometry  

PubMed Central

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

2011-01-01

218

Analyses of macrolide antibiotic residues in eggs, raw milk, and honey using both ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry and high-performance liquid chromatography/tandem mass spectrometry.  

PubMed

Two liquid chromatography mass spectrometric techniques, i.e. ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-Tof MS) and high-performance liquid chromatography/tandem mass spectrometry (LC/MS/MS), were used for quantification, confirmation or identification of six macrolide antibiotic residues and/or their degradation products in eggs, raw milk, and/or honey. Macrolides were extracted from food samples by acetonitrile or phosphate buffer (0.1 M, pH 8.0), and sample extracts were further cleaned up using solid-phase extraction cartridges. UPLC/Q-Tof data were acquired in Tof MS full scan mode that allowed both quantification and confirmation of macrolides, and identification of their degradation products. LC/MS/MS data acquisition was achieved using multiple reaction monitoring (MRM), i.e. two transitions, to provide a high degree of sensitivity and repeatability. Matrix-matched standard calibration curves with the use of roxithromycin as an internal standard were utilized to achieve the best accuracy of the method. Both techniques demonstrated good quantitative performance in terms of accuracy and repeatability. LC/MS/MS had advantages over UPLC/Q-Tof MS in that its limits of detection were lower and repeatability was somewhat better. UPLC/Q-Tof provided ultimate and unequivocal confirmation of positive findings, and allowed degradation product identification based on accurate mass. The combination of the two techniques can be very beneficial or complementary in routine analysis of macrolide antibiotic residues and their degradation products in food matrices to ensure the safety of food supply. PMID:17768705

Wang, Jian; Leung, Daniel

2007-01-01

219

Identification of parotid salivary biomarkers in Sjogren's syndrome by surface-enhanced laser desorption\\/ionization time-of-flight mass spectrometry and two-dimensional difference gel electrophoresis  

Microsoft Academic Search

Objectives. To identify the most significant salivary biomarkers in Sjogren's syndrome (SS) using proteomic methods. Methods. Parotid saliva from 20 non-SS subjects and 41 primary SS patients was analysed. Protein expression profiles for each sample were generated by surface-enhanced laser desorption\\/ionization time-of-flight-mass spectrometry (SELDI-TOF-MS). Mean peak intensities of SS patients and non-SS subjects were compared by univariate analyses. Samples pooled

O. H. Ryu; J. C. Atkinson; G. T. Hoehn; G. G. Illei; T. C. Hart

2006-01-01

220

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  

Microsoft Academic Search

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 spe- cies identification. By using 248 nonfermenting culture collection strains composed of 37 genera most

A. Mellmann; J. Cloud; T. Maier; U. Keckevoet; I. Ramminger; P. Iwen; J. Dunn; G. Hall; D. Wilson; P. LaSala; M. Kostrzewa; D. Harmsen

2008-01-01

221

Application of head-space solid-phase microextraction coupled to comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry for the determination of multiple pesticide residues in tea samples  

Microsoft Academic Search

A new method has been developed to detect 36 pesticides that may contaminate tea samples (green, black and fruit tea). The hyphenation of solid-phase microextraction in head-space mode with a comprehensive two-dimensional gas chromatography coupled with high-speed time-of-flight mass spectrometry (HS-SPME–GC×GC\\/TOF MS) proved to be a quick alternative to conventional GC\\/MS methodology which employs solvent-based extraction. The key parameters for

J. Schurek; T. Portolés; J. Hajslova; K. Riddellova; F. Hernández

2008-01-01

222

Rapid wide-scope screening of drugs of abuse, prescription drugs with potential for abuse and their metabolites in influent and effluent urban wastewater by ultrahigh pressure liquid chromatography–quadrupole-time-of-flight-mass spectrometry  

Microsoft Academic Search

This work illustrates the potential of hybrid quadrupole-time-of-flight mass spectrometry (QTOF MS) coupled to ultrahigh pressure liquid chromatography (UHPLC) to investigate the presence of drugs of abuse in wastewater. After solid-phase extraction with Oasis MCX cartridges, seventy-six illicit drugs, prescription drugs with potential for abuse, and metabolites were investigated in the samples by TOF MS using electrospray interface under positive

Félix Hernández; Lubertus Bijlsma; Juan V. Sancho; Ramon Díaz; María Ibáñez

2011-01-01

223

Analysis of recombinant DNA-derived glycoproteins via high-performance capillary electrophoresis coupled with off-line matrix-assisted laser desorption ionization time-of-flight mass spectrometry  

Microsoft Academic Search

This paper describes the analysis of glycoform populations of the glycoproteins ovalbumin and Desmodus salivary plasminogen activator (DSPA ?1) by a combination of capillary electrophoresis (CE) and off-line matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Ovalbumin has a single N-linked glycosylation site and DSPA ?1 has six sites for potential glycosylation, 2 N-linked and four O-linked. The conditions used

John A. Chakel; Erno Pungor; William S. Hancock; Sally A. Swedberg

1997-01-01

224

Determination of Oligopeptide Diversity within a Natural Population of Microcystis spp. (Cyanobacteria) by Typing Single Colonies by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry  

Microsoft Academic Search

Besides the most prominent peptide toxin, microcystin, the cyanobacteria Microcystis spp. have been shown to produce a large variety of other bioactive oligopeptides. We investigated for the first time the oligopeptide diversity within a natural Microcystis population by analyzing single colonies directly with matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The results demonstrate a high diversity of

JUTTA FASTNER; MARCEL ERHARD; HANS VON DOHREN

2001-01-01

225

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

226

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

227

Nitrocellulose film substrate minimizes fragmentation in matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of triacylglycerols.  

PubMed

The potential of matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) for the analysis of intact triacylglycerols (TAGs) is generally limited by the extensive in-source prompt fragmentation. The sequential deposition of matrix and TAGs over the stainless steel target precoated with a thin layer of nitrocellulose (NC) drastically reduced fragmentation in the MALDI-TOF MS profiling of oils and fats. The NC MALDI-TOF MS profiles of native and thermally stressed virgin olive oil and butter are reported as case studies, along with test analyses of a standard mixture of mono-, di-, and triacylglycerols. Mass spectra were almost completely devoid of both fragment and matrix ion signals, thus disclosing relevant information, especially in the low molecular mass range. The detection of several partial acylglycerols of low abundance and minor TAGs that are barely observed with other techniques also provided evidence for an increased dynamic range of NC MALDI-TOF MS that was due to the minimization of suppressive effects. The NC film substrate also improved the shot-to-shot and sample-to-sample reproducibility of the ion production through the exhibition of a more homogeneous matrix/analyte cocrystallization, thus enabling MALDI-based measurements to a consistent quantification of TAGs. PMID:20533836

Picariello, Gianluca; Romano, Raffaele; Addeo, Francesco

2010-07-01

228

MALDI-TOF mass spectrometry as a tool for the discrimination of high-risk Escherichia coli clones from phylogenetic groups B2 (ST131) and D (ST69, ST405, ST393).  

PubMed

Reliable, quick and low-cost methods are needed for the early detection of multidrug-resistant and highly virulent high-risk B2 and D Escherichia coli clones or clonal complexes (HiRCC). Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) seems to have a good discriminatory potential at different subspecies levels, but it was never evaluated for the discrimination of E. coli clones. We assessed the potential of MALDI-TOF MS coupled to multivariate data analysis to discriminate representative E. coli B2 and D HiRCC. Seventy-three E. coli isolates from B2 (including ST131 and B2 non-ST131 clones) and D (ST69, ST393, ST405) with variable pulsed-field gel electrophoresis (PFGE) patterns, origins and dates (1980-2010) were tested. MS spectra were acquired from independent extracts obtained from different plate cultures in two different Microflex LT MALDI-TOF devices (Bruker) after a standard extraction procedure. MALDI-TOF MS fingerprinting analysis revealed a good discriminatory ability between the four HiRCC analysed (ST131, ST69, ST405, ST393) and between B2 ST131 and other B2 non-ST131 isolates. Clusters defined by MALDI-TOF MS were consistent with the clonal complexes assigned by multilocus sequence typing (MLST), although differences were detected regarding the composition of clusters obtained by the comparison of PFGE profiles. We demonstrate, for the first time, that characteristic mass fingerprints of different E. coli HiRCC are sufficiently discriminatory and robust to enable their differentiation by MALDI-TOF MS, which might represent a promising tool for the optimisation of infection control, individual patient management and large-scale epidemiological studies of public health relevance. The good correlation between phenotypic and genotypic features further corroborates phylogenetic relationships delineated by MLST. PMID:24599708

Novais, Â; Sousa, C; de Dios Caballero, J; Fernandez-Olmos, A; Lopes, J; Ramos, H; Coque, T M; Cantón, R; Peixe, L

2014-08-01

229

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

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; Carroll, K C

2012-10-01

230

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

231

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

232

Rare earth elements determined in Antarctic ice by inductively coupled plasma--time of flight, quadrupole and sector field-mass spectrometry: An inter-comparison study.  

PubMed

Inductively coupled plasma mass spectrometry (ICP-MS) is a suitable tool for multi-element analysis at low concentration levels. Rare earth element (REE) determinations in standard reference materials and small volumes of molten ice core samples from Antarctica have been performed with an ICP-time of flight-MS (ICP-TOF-MS) system. Recovery rates for REE in e.g. SPS-SW1 amounted to approximately 103%, and the relative standard deviations were 3.4% for replicate analysis at REE concentrations in the lower ngL(-1) range. Analyses of REE concentrations in Antarctic ice core samples showed that the ICP-TOF-MS technique meets the demands of restricted sample mass. The data obtained are in good agreement with ICP-Quadrupole-MS (ICP-Q-MS) and ICP-Sector Field-MS (ICP-SF-MS) results. The ICP-TOF-MS system determines accurately and precisely REE concentrations exceeding 5ngL(-1) while between 0.5 and 5ngL(-1) accuracy and precision are element dependent. PMID:18573377

Dick, D; Wegner, A; Gabrielli, P; Ruth, U; Barbante, C; Kriews, M

2008-07-28

233

Differentiation of Campylobacter species by surface-enhanced laser desorption/ionization-time-of-flight mass spectrometry.  

PubMed

The genus Campylobacter contains several, widespread pathogens causing food-borne diseases of zoonotic nature in humans. In case of outbreaks, the differentiation of closely related Campylobacter is essential for epidemiological studies, which investigate the routes of geographical spread and ways of transmission. Recent advances in mass spectrometry (MS) have shown that matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) MS is a valuable tool for speciation of bacteria such as Campylobacter. Surface-enhanced laser desorption/ionization (SELDI)-TOF-MS is a specific MALDI-TOF application that combines a chip-based chromatographic enrichment of proteins with TOF-MS. This pilot study aims at investigating for the first time whether SELDI-TOF-MS can be applied for discrimination of Campylobacter at the level of species and even strains. Campylobacter type-strains and isolates from different regions were cultured and subsequently subjected to physicochemical lysis. Protein lysates were then applied on CM10 and IMAC30 ProteinChip Array surfaces and analyzed using a PCS 4000 SELDI Protein Chip System (Bio-Rad Laboratories). By comparison of the spectra from Campylobacter jejuni, Campylobacter coli, Campylobacter upsaliensis, and Campylobacter lari, 166 and 160 different protein peaks were observed (p<0.05) using CM10 and IMAC30 chips, respectively. Development of classification trees, comprising 2-4 of these peaks, allows for discrimination of different Campylobacter species and even strains. Moreover, species and strains can be sufficiently separated from each other by hierarchical cluster analysis. Thus, SELDI-TOF-MS is a promising tool to differentiate Campylobacter species and even strains. Species/strain-specific ions observed in addition to well-established markers identified by MALDI-TOF might be of value for future Campylobacter-identifying algorithms. To further clarify the potential advantages of this method, our results have to be validated against several independent test datasets of, preferably, a multitude of prospectively collected different isolates and compared with other typing techniques. PMID:21524195

Kiehntopf, Michael; Melcher, Franka; Hänel, Ingrid; Eladawy, Hosny; Tomaso, Herbert

2011-08-01

234

Analysis of RNA cleavage by MALDI-TOF mass spectrometry.  

PubMed

A method of analysis is presented that utilizes matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) to monitor the kinetics and products of RNA cleavage, by use of a program designed to mass-match observed MS peaks with predicted RNA cleavage products. The method is illustrated through application to the study of targeted oxidation of RNA stem loops from HIV-1 Rev Response Element mRNA (RRE RNA) and ribosomal 16S A-site RNA (16S RNA) by metallonucleases. Following incubation of each RNA with catalysts and/or redox co-reactants, reaction mixtures were desalted, and MALDI-TOF MS was used to monitor both time-resolved formation of cleavage products and disappearance of full-length RNA. For each RNA, a unique list was generated that contained the predicted masses of both the full-length, and all of the possible RNA cleavage fragments that resulted from the combination of all possible cleavage sites and each of the six expected overhangs formed at nascent termini adjacent to the cleavage sites. The overhangs corresponded to 2',3'-cyclic phosphate, 3'-phosphate, 3'-phosphoglycolate, 5'- hydroxyl and 5'- phosphate, which corresponded to differing oxidative, hydrolytic, and/or 2'-OH-mediated-endonucleolytic modes of scission. Each mass spectrum was compared with a corresponding list of predicted masses, and peaks were rapidly assigned by use of a Perl script, with a mass-matching tolerance of 200 ppm. Both time-dependent cleavage mediated by metallonucleases and MALDI-TOF-induced fragmentation were observed, and these were distinguished by time-dependent experiments. The resulting data allowed a semi-quantitative assessment of the rate of formation of each overhang at each nucleotide position. Limitations included artifactual skewing of quantification by mass bias, a limited mass range for quantification, and a lack of detection of secondary cleavage products. Nevertheless, the method presented herein provides a rapid, accurate, highly-detailed and semi-quantitative analysis of RNA cleavage that should be widely applicable. PMID:22941655

Joyner, Jeff C; Keuper, Kevin D; Cowan, J A

2013-01-01

235

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

236

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

2013-07-12

237

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.

2011-06-13

238

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

239

Identification of Gram-Positive Cocci by Use of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry: Comparison of Different Preparation Methods and Implementation of a Practical Algorithm for Routine Diagnostics  

PubMed Central

This study compared three sample preparation methods (direct transfer, the direct transfer-formic acid method with on-target formic acid treatment, and ethanol-formic acid extraction) for the identification of Gram-positive cocci with matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). A total of 156 Gram-positive cocci representing the clinically most important genera, Aerococcus, Enterococcus, Staphylococcus, and Streptococcus, as well as more rare genera, such as Gemella and Granulicatella, were analyzed using a Bruker MALDI Biotyper. The rate of correct genus-level identifications was approximately 99% for all three sample preparation methods. The species identification rate was significantly higher for the direct transfer-formic acid method and ethanol-formic acid extraction (both 77.6%) than for direct transfer (64.1%). Using direct transfer-formic acid compared to direct transfer, the total time to result was increased by 22.6%, 16.4%, and 8.5% analyzing 12, 48, and 96 samples per run, respectively. In a subsequent prospective study, 1,619 clinical isolates of Gram-positive cocci were analyzed under routine conditions by MALDI-TOF MS, using the direct transfer-formic acid preparation, and by conventional biochemical methods. For 95.6% of the isolates, a congruence between conventional and MALDI-TOF MS identification was observed. Two major limitations were found using MALDI-TOF MS: the differentiation of members of the Streptococcus mitis group and the identification of Streptococcus dysgalactiae. The Bruker MALDI Biotyper system using the direct transfer-formic acid sample preparation method was shown to be a highly reliable tool for the identification of Gram-positive cocci. We here suggest a practical algorithm for the clinical laboratory combining MALDI-TOF MS with phenotypic and molecular methods. PMID:23554198

Schulthess, Bettina; Brodner, Katharina; Bloemberg, Guido V.; Zbinden, Reinhard; Bottger, Erik C.

2013-01-01

240

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

241

A generic screening methodology for horse doping control by LC-TOF-MS, GC-HRMS and GC-MS.  

PubMed

In the present study a general screening protocol was developed to detect prohibited substances and metabolites for doping control purposes in equine sports. It was based on the establishment of a unified sample preparation and on the combined implementation of liquid and gas chromatographic MS analysis. The sample pretreatment began with two parallel procedures: enzymatic hydrolysis of sulfate and glucuronide conjugates, and methanolysis of the 17?-sulfate steroid conjugates. The extracts were treated for LC-TOF-MS, GC-HRMS and GC-MS assays. The majority of the prohibited substances were identified through a high mass accuracy technique, such as LC-TOF-MS, without prior derivatization. The sample preparation procedure included the formation of methylated and trimethylsilylated derivatives common in toxicological GC-MS libraries. The screening method was enhanced by post-run library searching using automated mass spectral deconvolution and identification system (AMDIS) combined with deconvolution reporting software (DRS). The current methodology is able to detect the presence of more than 350 target analytes in horse urine and may easily incorporate a lot of new substances without changes in chromatography. The full scan acquisition allows retrospective identification of prohibited substances in stored urine samples after reprocessing of the acquired data. Validation was performed for sixty representative compounds and included limit of detection, matrix interference - specificity, extraction recovery, precision, mass accuracy, matrix effect and carry over contamination. The suitability of the method was demonstrated with previously declared positive horse urine samples. PMID:24185097

Kioussi, Maroula K; Lyris, Emmanouil M; Angelis, Yiannis S; Tsivou, Maria; Koupparis, Michael A; Georgakopoulos, Costas G

2013-12-15

242

Qualitative and quantitative analysis on chemical constituents from Curculigo orchioides using ultra high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry.  

PubMed

A rapid ultra-high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC-ESI-Q-TOF/MS) method was developed for qualitative and quantitative determination of constituents in the rhizome of Curculigo orchioides. Qualitative analysis was performed on a Waters ACQUITY UHPLC @ HSS T3 column (1.8?m 100×2.1mm) using gradient elution with mobile phase of 0.1% formic acid and acetonitrile. Quantitative analysis was performed on an Agilent ZORBAX Eclipse plus C18 column (1.7?m 100×2.1mm) using gradient elution with mobile phase of 0.1% acetic acid and acetonitrile for at least 20min. Quadrupole TOF/MS in either full scan mode or extracted ion mode was used for qualitative and quantitative analysis of the constituents. According to the mass spectrometric fragmentation mechanism and UHPLC-ESI-Q-TOF-MS data, chemical structures of 45 constituents in the rhizome of Curculigo orchioides, including 19 phenols and phenolic glycosides, 16 lignans and lignan glycosides, 8 triterpenoid saponins, one flavone and one sesquiterpene, were identified tentatively on-line without the time-consuming process of isolation. In addition, 8 phenolic glycosides including 5-hydroxymethylfurfural (HMF), 2-hydroxy-5-(2-hydroxyethyl) phenyl-?-d-glucopyranoside (HPG), anacardoside (ACD), orcinol glucoside (OGD), orcinol-1-O-?-d-apiofuranosyl-(1?6)-?-d-glucopyranoside (OAG), 2,6-dimethoxybenzoic acid (DBA), curculigoside (CUR) and curculigine A (CCL) were quantitated in 11 collected samples and 10 commercial samples from different providers. The results show that UHPLC-ESI-Q-TOF-MS is a viable method for analysis and quality evaluation of the constituents from the rhizome of Curculigo orchioides. PMID:25305598

He, Yongjing; Dong, Xin; Jia, Xiaoxuan; Li, Mei; Yuan, Tingting; Xu, Hongtao; Qin, Luping; Han, Ting; Zhang, Qiaoyan

2015-01-01

243

Rapid identification of Mycoplasma pulmonis isolated from laboratory mice and rats using matrix-assisted laser desorption ionization time-of-flight mass spectrometry.  

PubMed

Mycoplasma species identification is based on biochemical, immunological, and molecular methods that require several days for accurate identification. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a novel method for identification of bacteria and has recently been introduced into the clinical microbiology laboratory as a rapid and accurate technique. This method allows a characteristic mass spectral fingerprint to be obtained from whole inactivated mycoplasmal cells. In this study, we evaluated the performance of the MALDI-TOF MS for the identification of Mycoplasma by comparison with standard sequence analysis of 16S rRNA. We developed the first database of MALDI-TOF MS profiles of Mycoplasma species, containing Mycoplasma pulmonis, M. arthritidis, and M. neurolyticum, which are the most common pathogens in mice and/or rats, and species-specific spectra were recorded. Using the database, 6 clinical isolates were identified. Six tracheal swabs from 4 mice and 2 rats were cultured on PPLO agar for 4 to 7 days, and the colonies were directly applied to analyze the protein profiles. Five strains were identified as M. pulmonis, and 1 strain from a mouse was identified as M. neurolyticum (spectral scores were >2.00); the results were consistent with the results of the 16S rRNA gene sequence analysis (homologies>97.0%). These data indicate that MALDI-TOF MS can be used as a clearly rapid, accurate, and cost-effective method for the identification of M. pulmonis isolates, and this system may represent a serious alternative for clinical laboratories to identify Mycoplasma species. PMID:22498928

Goto, Kazuo; Yamamoto, Mikachi; Asahara, Miwa; Tamura, Takashi; Matsumura, Mitsuru; Hayashimoto, Nobuhito; Makimura, Koichi

2012-08-01

244

Studies on substantially increased proteins in follicular fluid of bovine ovarian follicular cysts using 2-D PAGE and MALDI-TOF MS  

PubMed Central

Background The objective of this study was to identify substantially increased proteins in bovine cystic follicular fluid (FF) in order to clarify the pathology and etiology of bovine ovarian follicular cysts (BOFC). Methods Proteins in normal and cystic FF samples were subjected to two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and were compared using silver stained gel images with PDQuest image analysis software. Peptides from these increased spots were analyzed by matrix assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS), and were identified based on the NCBI database by a peptide mass fingerprinting method. Results Comparative proteomic analysis showed 8 increased protein spots present in cystic FF. MS analysis and database searching revealed that the increased proteins in cystic FF were bovine mitochondrial f1-atpase (BMFA), erythroid associated factor (EAF), methionine synthase (MeS), VEGF-receptor, glyceraldehydes 3-phosphate dehydrogenase (GAPDH), heat shock protein 70 (HSP70), ?-lactoglobulin (BLG) and succinate dehydrogenase Ip subunit (SD). Conclusion Our results suggest that these proteins are overexpressed in BOFC, and that they may play important roles in the pathogenesis of BOFC. Furthermore, these proteins in the FF could be useful biomarkers for BOFC. PMID:15941490

Maniwa, Jiro; Izumi, Shunsuke; Isobe, Naoki; Terada, Takato

2005-01-01

245

Rapid characterization of chemical constituents and rats metabolites of the traditional Chinese patent medicine Gegen-Qinlian-Wan by UHPLC/DAD/qTOF-MS.  

PubMed

Gegen-Qinlian-Wan (GQW) is a popular traditional Chinese patent medicine for the treatment of diarrhea. It is composed of four herbal medicines, Puerariae Radix, Scutellariae Radix, Coptidis Rhizoma, and Glycyrrhizae Radix. In this study, a rapid and sensitive method based on ultra high-performance liquid chromatography coupled with diode-array detection and quadrupole time-of-flight mass spectrometry (UHPLC-DAD-qTOF-MS) was established to characterize the chemical constituents and rats metabolites of GQW. Samples were separated on an Agilent Zorbax Eclipse Plus-C(18) column (100 mm × 2.1 mm, 1.8 ?m) by gradient elution using acetonitrile and water containing 0.1% formic acid as the mobile phase. On the basis of UV and qTOF high-accuracy mass spectral analysis, a total of 62 compounds were identified or tentatively characterized from GQW, including 42 flavonoids, 8 alkaloids, 6 triterpenoids, 3 phenylethanoid glycosides, and 3 other types. Among them, 27 compounds were confirmed by comparing with reference standards. Furthermore, metabolites in rats plasma and urine after oral administration of GQW were also analyzed. A total of 42 compounds were identified, including 29 prototypes and 13 metabolites through metabolic pathways of demethylation, methylation, hydrolysis, sulfate conjugation, and glucuronide conjugation. Glucuronidated flavonoids were the main constituents in the plasma, and were then transformed into aglycones and excreted from urine. This is the first systematic study on the chemical constituents and metabolic profiling of GQW. PMID:23146232

Miao, Wen-juan; Wang, Qing; Bo, Tao; Ye, Min; Qiao, Xue; Yang, Wen-zhi; Xiang, Cheng; Guan, Xiang-yu; Guo, De-an

2013-01-01

246

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

247

Advances in Quantitative Hepcidin Measurements by Time-of-Flight Mass Spectrometry  

PubMed Central

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 concerned spiking of a synthetic hepcidin analogue as internal standard into serum and urine samples. This serves both as a control for experimental variation, such as recovery and matrix-dependent ionization and ion suppression, and at the same time allows value assignment to the measured hepcidin peak intensities. The assay improvements were clinically evaluated using samples from various patients groups and its relevance was further underscored by the significant correlation of serum hepcidin levels with serum iron indices in healthy individuals. Most importantly, this approach allowed kinetic studies as illustrated by the paired analyses of serum and urine samples, showing that more than 97% of the freely filtered serum hepcidin can be reabsorbed in the kidney. Thus, the here reported advances in TOF MS-based hepcidin measurements represent critical steps in the accurate quantification of hepcidin in various body fluids and pave the way for clinical studies on the kinetic behavior of hepcidin in both healthy and diseased states. PMID:18628991

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

2008-01-01

248

Direct Laser Ablation and Ionization of Solids for Chemical Analysis by Mass Spectrometry  

SciTech Connect

A laser ablation/ionization mass spectrometer system is described for the direct chemical analysis of solids. An Nd:YAG laser is used for ablation and ionization of the sample in a quadrupole ion trap operated in an ion-storage (IS) mode that is coupled with a reflectron time-of-flight mass spectrometer (TOF-MS). Single pulse experiments have demonstrated simultaneous detection of up to 14 elements present in glasses in the ppm range. However, detection of the components has produced non-stoichiometric results due to difference in ionization potentials and fractionation effects. Time-of-flight secondary ionization mass spectrometry (TOF-SIMS) was used to spatially map elemental species on the surface and provide further evidence of fractionation effects. Resolution (m/Dm) of 1500 and detection limits of approximately 10 pg have been achieved with a single laser pulse. The system configuration and related operating principles for accurately measuring low concentrations of isotopes are described.

Holt, J K; Nelson, E J; Klunder, G L

2005-09-02

249

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

250

Application of delayed extraction matrix-assisted laser desorption ionization time-of-flight mass spectrometry for analysis of sphingolipids in tissues from sphingolipidosis patients.  

PubMed

Sphingolipidosis is due to defects in enzymes involved in hydrolysis of sphingolipids. We analyzed sphingolipids in tissues from patients with sphingolipidosis, including Farber disease (FD, acid ceramidase deficiency), Gaucher disease (GD), Niemann-Pick disease type C (NPDC), and GM1-gangliosidosis (GM1G), using delayed extraction matrix-assisted laser desorption ionization time-of-flight mass spectrometry (DE MALDI-TOF-MS). Crude lipids were extracted from about 100 mg wet weight of autopsied tissues, including liver, spleen, cerebrum or cerebellum. After mild alkaline treatment, a sphingolipid fraction was prepared from the crude lipids and analyzed by DE MALDI-TOF-MS. The results were as follows: (a) In FD liver both the ceramide/sphingomyelin and ceramide/monohexosylceramide ratios were significantly high; (b) in both liver and spleen from a GD patient, the glucosylceramide/sphingomyelin ratio was raised; (c) in liver from a NPDC patient, the monohexosylceramide/sphingomyelin ratio was markedly low, suggesting an increase of sphingomyelin; and (d) in all tissues examined in the GM1G patient, GM1-gangliosides or asialo-GM1-gangliosides, that are undetectable in a normal control, were increased. In conclusion, sphingolipids in human tissues could be directly determined by DE MALDI-TOF-MS, with only a small amount of specimens. This method will be useful for the diagnosis and biochemical evaluation of sphingolipidosis patients. PMID:10491988

Fujiwaki, T; Yamaguchi, S; Sukegawa, K; Taketomi, T

1999-08-01

251

Direct Analysis in Real Time Mass Spectrometry (DART-MS) Analysis of Skin Metabolome Changes in the Ultraviolet B-Induced Mice  

PubMed Central

Ultraviolet (UV) radiation is a major environmental factor that leads to acute and chronic reactions in the human skin. UV exposure induces wrinkle formation, DNA damage, and generation of reactive oxygen species (ROS). Most mechanistic studies of skin physiology and pharmacology related with UV-irradiated skin have focused on proteins and their related gene expression or single- targeted small molecules. The present study identified and analyzed the alteration of skin metabolites following UVB irradiation and topical retinyl palmitate (RP, 5%) treatment in hairless mice using direct analysis in real time (DART) time-of-flight mass spectrometry (TOF-MS) with multivariate analysis. Under the negative ion mode, the DART ion source successfully ionized various fatty acids including palmitoleic and linolenic acid. From DART-TOF-MS fingerprints measured in positive mode, the prominent dehydrated ion peak (m/z: 369, M+H-H2O) of cholesterol was characterized in all three groups. In positive mode, the discrimination among three groups was much clearer than that in negative mode by using multivariate analysis of orthogonal partial-least squares-discriminant analysis (OPLS-DA). DART-TOF-MS can ionize various small organic molecules in living tissues and is an efficient alternative analytical tool for acquiring full chemical fingerprints from living tissues without requiring sample preparation. DART-MS measurement of skin tissue with multivariate analysis proved to be a powerful method to discriminate between experimental groups and to find biomarkers for various experiment models in skin dermatological research. PMID:24404338

Park, Hye Min; Kim, Hye Jin; Jang, Young Pyo; Kim, Sun Yeou

2013-01-01

252

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

253

MALDI-TOF MS based identification of food-borne yeast isolates.  

PubMed

In this study, food-borne yeast isolates (n=96), comprising at least 33 species, were identified using MALDI-TOF MS and conventional methods (API ID 32 C and Phoenix Yeast ID). Discrepancies of both methods were resolved by sequencing the ITS1-5.8S-rRNA-ITS2 region. For ten isolates, mainly classified to Rhodotorula and Trichosporon species, no clear final species identification was possible. 62 isolates were correctly identified to species level using either MALDI-TOF MS or conventional tests. 15 isolates were misidentified when applying conventional assays. In contrary, no species misidentifications were observed after MALDI-TOF MS based classification. In return, 16 isolates were not identifiable after matching their protein fingerprints against MALDI Biotyper 4.0.0.1 library. MALDI TOF MS in-house database update clearly improved the identification. In conclusion, the presented data suggest that MALDI-TOF MS is an appropriate platform for reliable classification and identification of food-borne yeast isolates. PMID:25193440

Pavlovic, Melanie; Mewes, Anne; Maggipinto, Marzena; Schmidt, Wolfgang; Messelhäußer, Ute; Balsliemke, Joachim; Hörmansdorfer, Stefan; Busch, Ulrich; Huber, Ingrid

2014-11-01

254

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.

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

2014-01-01

255

Impact of rapid microbial identification directly from positive blood cultures using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry on patient management.  

PubMed

For septic patients, delaying the initiation of antimicrobial therapy or choosing an inappropriate antibiotic can considerably worsen their prognosis. This study evaluated the impact of rapid microbial identification (RMI) from positive blood cultures on the management of patients with suspected sepsis. During a 6-month period, RMI by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was performed for all new episodes of bacteraemia. For each patient, the infectious disease specialist was contacted and questioned about his therapeutic decisions made based on the Gram staining and the RMI. This information was collected to evaluate the number of RMIs that led to a therapeutic change or to a modification of the patient's general management (e.g. fast removal of infected catheters). During the study period, 277 new episodes of bacteraemia were recorded. In 71.12% of the cases, MALDI-TOF MS resulted in a successful RMI (197/277). For adult and paediatric patients, 13.38% (21/157) and 2.50% (1/40) of the RMIs, respectively, resulted in modification of the treatment regimen, according to the survey. In many other cases, the MALDI-TOF MS was a helpful tool for infectious disease specialists because it confirmed suspected cases of contamination, especially in the paediatric population (15/40 RMIs, 37.50%), or suggested complementary diagnostic testing. This study emphasizes the benefits of RMI from positive blood cultures. Although the use of this technique represents an extra cost for the laboratory, RMI using MALDI-TOF MS has been implemented in our daily practice. PMID:23890423

Martiny, D; Debaugnies, F; Gateff, D; Gérard, M; Aoun, M; Martin, C; Konopnicki, D; Loizidou, A; Georgala, A; Hainaut, M; Chantrenne, M; Dediste, A; Vandenberg, O; Van Praet, S

2013-12-01

256

Identification of coagulase-negative staphylococci from bovine intramammary infection by matrix-assisted laser desorption ionization-time of flight mass spectrometry.  

PubMed

Coagulase-negative staphylococci (CoNS) are among the main pathogens causing bovine intramammary infection (IMI) in many countries. However, one of the limitations related to the specific diagnosis of CoNS is the lack of an accurate, rapid, and convenient method that can differentiate the bacterial species comprising this group. The aim of this study was to evaluate the ability of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) to accurately identify CoNS species in dairy cow IMI. In addition, the study aimed to determine the frequency of CoNS species causing bovine IMI. A total of 108 bacterial isolates were diagnosed as CoNS by microbiological cultures from two milk samples collected from 21 dairy herds; the first sample was collected at the cow level (i.e., 1,242 composite samples from all quarters), while the second sample was collected at the mammary quarter level (i.e., 1,140 mammary samples collected from 285 cows). After CoNS isolation was confirmed by microbiological culture for both samples, all CoNS isolates (n=108) were genotypically differentiated by PCR restriction fragment length polymorphism (RFLP) analysis of a partial groEL gene sequence and subjected to the MALDI-TOF MS identification procedure. MALDI-TOF MS correctly identified 103 (95.4%) of the CoNS isolates identified by PCR-RFLP at the species level. Eleven CoNS species isolated from bovine IMI were identified by PCR-RFLP, and the most prevalent species was Staphylococcus chromogenes (n=80; 74.1%). In conclusion, MALDI-TOF MS may be a reliable alternative method for differentiating CoNS species causing bovine IMI. PMID:24622096

Tomazi, Tiago; Gonçalves, Juliano Leonel; Barreiro, Juliana Regina; de Campos Braga, Patrícia Aparecida; Prada e Silva, Luis Felipe; Eberlin, Marcos Nogueira; dos Santos, Marcos Veiga

2014-05-01

257

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

258

Rapid determination of total solanesol in tobacco leaf by ultrasound-assisted extraction with RP-HPLC and ESI-TOF/MS.  

PubMed

A reliable and rapid method based on high-performance liquid chromatography (HPLC-UV) and positive ion electrospray-time of flight mass spectrometry (ESI-TOF/MS) has been developed for the characterization and quantification of solanesol in extracts of tobacco leaves from different sources. The solanesol was extracted from tobacco leaf via saponification and ultrasonic-assist extraction, and the extraction conditions were optimized. The HPLC conditions are as following: Hypersil C(4) (4.6 mm x 150 mm, 5 microm) column, acetonitrile and water as mobile phase, flow-rate is 0.8 ml/min, detection length of UV is 202 nm, injection volume is 10 microl. The results indicated that the developed HPLC method is simple, sensitive and reliable for the determination of solanesol in tobacco leaves with a linear dynamic range of 3.65-4672 ng, a detection limit of 1.83 ng, and an average recovery of 98.7%. The method has been applied to analyze and compare different tobacco samples. The results show that the solanesol content in samples of different geographic locations varies widely from 0.20 to 1.50%. When different parts of the tobacco plant are compared, the top parts of the leaves are more abundant in solanesol content than those of lower parts. PMID:17029669

Chen, Junhui; Liu, Xianping; Xu, Xiaoqin; Lee, Frank Sen-Chun; Wang, Xiaoru

2007-02-19

259

Discovery of safety biomarkers for realgar in rat urine using UFLC-IT-TOF/MS and 1H NMR based metabolomics.  

PubMed

As an arsenical, realgar (As4S4) is known as a poison and paradoxically as a therapeutic agent. However, a complete understanding of the precise biochemical alterations accompanying the toxicity and therapy effects of realgar is lacking. Using a combined ultrafast liquid chromatography (UFLC) coupled with ion trap time-of-flight mass spectrometry (IT-TOF/MS) and (1)H NMR spectroscopy based metabolomics approach, we were able to delineate significantly altered metabolites in the urine samples of realgar-treated rats. The platform stability of the liquid chromatography LC/MS and NMR techniques was systematically investigated, and the data processing method was carefully optimized. Our results indicate significant perturbations in amino acid metabolism, citric acid cycle, choline metabolism, and porphyrin metabolism. Thirty-six metabolites were proposed as potential safety biomarkers related to disturbances caused by realgar, and glycine and serine are expected to serve as the central contacts in the metabolic pathways related to realgar-induced disturbance. The LC/MS and NMR based metabolomics approach established provided a systematic and holistic view of the biochemical effects of realgar on rats, and might be employed to investigate other drugs or xenobiotics in the future. PMID:23479124

Huang, Yin; Tian, Yuan; Li, Geng; Li, Yuanyuan; Yin, Xinjuan; Peng, Can; Xu, Fengguo; Zhang, Zunjian

2013-05-01

260

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

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

261

Conceptual Study on New Isotope Analysis Technique with Resonance Ionization Mass Spectrometry Using Inductively Coupled Plasma as an Atomic Source (ICP-RIMS)  

SciTech Connect

We have proposed the novel isotope analysis technique with Resonance Ionization Mass Spectrometry using Inductively Coupled Plasma as an atomic source (ICP-RIMS). Each component of ICP-RIMS is conceptually designed. We conclude that the orthogonal acceleration time-of-flight mass spectrometer (oa-TOF-MS) driven by a high-repetition-rate pulsed laser would be suitable system for ICP-RIMS. We, additionally, suggest that the first vacuum stage of the vacuum interface, which is between the sampling and skimmer cones, is desired to maintain as low pressure as possible in order to suppress the Doppler broadening and to skim the supersonic jet effectively.

Watanabe, K.; Uritani, A. [Department of Materials, Physics and Energy Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603 (Japan); Higuchi, Y.; Tomita, H.; Kawarabayashi, J.; Iguchi, T. [Department of Quantum Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603 (Japan)

2009-03-17

262

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

263

Application of MALDI-TOF Mass Spectrometry in Clinical Virology: A Review  

PubMed Central

MALDI-TOF mass spectrometry is a diagnostic tool of microbial identification and characterization based on the detection of the mass of molecules. In the majority of clinical laboratories, this technology is currently being used mainly for bacterial diagnosis, but several approaches in the field of virology have been investigated. The introduction of this technology in clinical virology will improve the diagnosis of infections produced by viruses but also the discovery of mutations and variants of these microorganisms as well as the detection of antiviral resistance. This review is focused on the main current applications of MALDI-TOF MS techniques in clinical virology showing the state of the art with respect to this exciting new technology. PMID:24222805

Cobo, Fernando

2013-01-01

264

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

265

The Use of MALDI-TOF Mass Spectrometry, Ribotyping and Phenotypic Tests to Identify Lactic Acid Bacteria from Fermented Cereal Foods in Abidjan (C?te 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.

Soro-Yao, Amenan A; Schumann, Peter; Thonart, Philippe; Dje, Koffi M; Pukall, Rudiger

2014-01-01

266

MASS SPECTROMETRY IN ENVIRONMENTAL SCIENCES  

EPA Science Inventory

This review covers applications of mass spectrometry to the environmental sciences. From the early applications of mass spectrometry to environmental research in the 1960s and 1970s, mass spectrometry has played an important role in aiding our understanding of environmental poll...

267

Biological Cluster Mass Spectrometry  

PubMed Central

This article reviews the new physics and new applications of secondary ion mass spectrometry using cluster ion probes. These probes, particularly C60, exhibit enhanced molecular desorption with improved sensitivity owing to the unique nature of the energy-deposition process. In addition, these projectiles are capable of eroding molecular solids while retaining the molecular specificity of mass spectrometry. When the beams are microfocused to a spot on the sample, bioimaging experiments in two and three dimensions are feasible. We describe emerging theoretical models that allow the energy-deposition process to be understood on an atomic and molecular basis. Moreover, experiments on model systems are described that allow protocols for imaging on biological materials to be implemented. Finally, we present recent applications of imaging to biological tissue and single cells to illustrate the future directions of this methodology. PMID:20055679

Winograd, Nicholas; Garrison, Barbara J.

2010-01-01

268

Matrix-Assisted Laser Desorption Ionization - Time of Flight Mass Spectrometry: An Emerging Tool for the Rapid Identification of Mosquito Vectors  

PubMed Central

Background The identification of mosquito vectors is typically based on morphological characteristics using morphological keys of determination, which requires entomological expertise and training. The use of protein profiling by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), which is increasingly being used for the routine identification of bacteria, has recently emerged for arthropod identification. Methods To investigate the usefulness of MALDI-TOF-MS as a mosquito identification tool, we tested protein extracts made from mosquito legs to create a database of reference spectra. The database included a total of 129 laboratory-reared and field-caught mosquito specimens consisting of 20 species, including 4 Aedes spp., 9 Anopheles spp., 4 Culex spp., Lutzia tigripes, Orthopodomyia reunionensis and Mansonia uniformis. For the validation study, blind tests were performed with 76 specimens consisting of 1 to 4 individuals per species. A cluster analysis was carried out using the MALDI-Biotyper and some spectra from all mosquito species tested. Results Biomarker mass sets containing 22 and 43 masses have been detected from 100 specimens of the Anopheles, Aedes and Culex species. By carrying out 3 blind tests, we achieved the identification of mosquito vectors at the species level, including the differentiation of An. gambiae complex, which is possible using MALDI-TOF-MS with 1.8 as the cut-off identification score. A cluster analysis performed with all available mosquito species showed that MALDI-Biotyper can distinguish between specimens at the subspecies level, as demonstrated for An gambiae M and S, but this method cannot yet be considered a reliable tool for the phylogenetic study of mosquito species. Conclusions We confirmed that even without any specific expertise, MALDI-TOF-MS profiling of mosquito leg protein extracts can be used for the rapid identification of mosquito vectors. Therefore, MALDI-TOF-MS is an alternative, efficient and inexpensive tool that can accurately identify mosquitoes collected in the field during entomological surveys. PMID:23977292

Yssouf, Amina; Socolovschi, Cristina; Flaudrops, Christophe; Ndiath, Mamadou Ousmane; Sougoufara, Seynabou; Dehecq, Jean-Sebastien; Lacour, Guillaume; Berenger, Jean-Michel; Sokhna, Cheikh Sadibou; Raoult, Didier; Parola, Philippe

2013-01-01

269

MALDI Mass Spectrometry Imaging of Neuronal Cell Cultures  

PubMed Central

Mass spectrometry imaging (MSI) provides the ability to detect and identify a broad range of analytes and their spatial distributions from a variety of sample types, including tissue sections. Here we describe an approach for probing neuropeptides from sparse cell cultures using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MSI—at single cell spatial resolution—in both MS and tandem MS modes. Cultures of Aplysia californica neurons are grown on an array of glass beads embedded in a stretchable layer of Parafilm M. As the membrane is stretched, the beads/neurons are separated physically and the separated beads/neurons analyzed via MALDI TOF MS. Compared with direct MS imaging of samples, the stretching procedure enhances analyte extraction and incorporation into the MALDI matrix, with negligible analyte spread between separated beads. MALDI tandem MSI using the stretched imaging approach yields localization maps of both parent and fragment ions from Aplysia pedal peptide, thereby confirming peptide identification. This methodology represents a flexible platform for MSI investigation of a variety of cell cultures, including functioning neuronal networks. PMID:21472517

Zimmerman, Tyler A.; Rubakhin, Stanislav S.; Sweedler, Jonathan V.

2011-01-01

270

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

271

Rapid identification of positive blood cultures by matrix-assisted laser desorption ionization-time of flight mass spectrometry using prewarmed agar plates.  

PubMed

This study describes an inexpensive and straightforward method for identifying bacteria by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) directly from positive blood cultures using prewarmed agar plates. Different inoculation methods and incubation times were evaluated to determine the optimal conditions. The two methods using pelleted material from positive culture bottles performed best. In particular, the pellet streak method correctly identified 94% of the Gram negatives following 4 h of incubation and 98% of the Gram positives following 6 h of incubation. PMID:25232166

Bhatti, M M; Boonlayangoor, S; Beavis, K G; Tesic, V

2014-12-01

272

Exploring infrared wavelength matrix-assisted laser desorption\\/ionization of proteins with delayed-extraction time-of-flight mass spectrometry  

Microsoft Academic Search

We report a study of the application of delayed extraction (DE) to infrared-wavelength matrix-assisted time-of-flight mass\\u000a spectrometry (IR-MALDI-TOF-MS) of proteins. The shapes of the spectral peaks obtained with DE-IR-MALDI-MS are compared with\\u000a those obtained from the same samples and matrix using continuous extraction (CE) IR-MALDI-MS. Application of DE results in\\u000a significant improvements in the peak resolution, revealing spectral features (in

Wenzhu Zhang; Shufang Niu; Brian T. Chait

1998-01-01

273

Optimized method for Acinetobacter species carbapenemase detection and identification by matrix-assisted laser desorption ionization-time of flight mass spectrometry.  

PubMed

The use of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for rapid detection and identification of the enzymes responsible for carbapenem resistance in Acinetobacter spp. appears as a promising option, but it will be necessary to have a standardized protocol that facilitates routine use. Based on the results reported herein and comparisons of several previously published reports, we identified the significant peaks for imipenem detection. Optimal bacterial inoculum and incubation time were established, and results obtained with and without dipicolinic acid (DPA) and Zn(2+) allowed us to distinguish between metallo-beta-lactamases and oxacillinases. PMID:23447631

Álvarez-Buylla, Adela; Picazo, Juan J; Culebras, Esther

2013-05-01

274

Optimized Method for Acinetobacter Species Carbapenemase Detection and Identification by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry  

PubMed Central

The use of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) for rapid detection and identification of the enzymes responsible for carbapenem resistance in Acinetobacter spp. appears as a promising option, but it will be necessary to have a standardized protocol that facilitates routine use. Based on the results reported herein and comparisons of several previously published reports, we identified the significant peaks for imipenem detection. Optimal bacterial inoculum and incubation time were established, and results obtained with and without dipicolinic acid (DPA) and Zn2+ allowed us to distinguish between metallo-beta-lactamases and oxacillinases. PMID:23447631

Picazo, Juan J.; Culebras, Esther

2013-01-01

275

Rapid Identification of Viridans Streptococci by Mass Spectrometric Discrimination?  

PubMed Central

Viridans streptococci (VS) are responsible for several systemic diseases, such as endocarditis, abscesses, and septicemia. Unfortunately, species identification by conventional methods seems to be more difficult than species identification of other groups of bacteria. The aim of the present study was to evaluate the use of cell matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) for the rapid identification of 10 different species of VS. A total of 99 VS clinical isolates, 10 reference strains, and 20 strains from our in-house culture collection were analyzed by MALDI-TOF-MS. To evaluate the mass-spectrometric discrimination results, all strains were identified in parallel by phenotypic and genotypic methods. MALDI-TOF-MS identified 71 isolates as the mitis group, 23 as the anginosus group, and 5 as Streptococcus salivarius. Comparison of the species identification results obtained by the MALDI-TOF-MS analyses and with the phenotypic/genotypic identification systems showed 100% consistency at the species level. Thus, MALDI-TOF-MS seems to be a rapid and reliable method for the identification of species of VS from clinical samples. PMID:17553974

Friedrichs, C.; Rodloff, A. C.; Chhatwal, G. S.; Schellenberger, W.; Eschrich, K.

2007-01-01

276

Evaluation of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Identification of Nocardia Species?  

PubMed Central

The identification of Nocardia species, usually based on biochemical tests together with phenotypic in vitro susceptibility and resistance patterns, is a difficult and lengthy process owing to the slow growth and limited reactivity of these bacteria. In this study, a panel of 153 clinical and reference strains of Nocardia spp., altogether representing 19 different species, were characterized by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). As reference methods for species identification, full-length 16S rRNA gene sequencing and phenotypical biochemical and enzymatic tests were used. In a first step, a complementary homemade reference database was established by the analysis of 110 Nocardia isolates (pretreated with 30 min of boiling and extraction) in the MALDI BioTyper software according to the manufacturer's recommendations for microflex measurement (Bruker Daltonik GmbH, Leipzig, Germany), generating a dendrogram with species-specific cluster patterns. In a second step, the MALDI BioTyper database and the generated database were challenged with 43 blind-coded clinical isolates of Nocardia spp. Following addition of the homemade database in the BioTyper software, MALDI-TOF MS provided reliable identification to the species level for five species of which more than a single isolate was analyzed. Correct identification was achieved for 38 of the 43 isolates (88%), including 34 strains identified to the species level and 4 strains identified to the genus level according to the manufacturer's log score specifications. These data suggest that MALDI-TOF MS has potential for use as a rapid (<1 h) and reliable method for the identification of Nocardia species without any substantial costs for consumables. PMID:20861335

Verroken, A.; Janssens, M.; Berhin, C.; Bogaerts, P.; Huang, T.-D.; Wauters, G.; Glupczynski, Y.

2010-01-01

277

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.

2011-06-08

278

Application of gas chromatography time-of-flight mass spectrometry for target and non-target analysis of pesticide residues in fruits and vegetables.  

PubMed

In this work, the capability of gas chromatography coupled to time-of-flight mass spectrometry (GC-TOF MS) for quantitative analysis of pesticide residues has been evaluated. A multiclass method for rapid screening of pesticides (insecticides, acaricides, herbicides and fungicides) in fruit and vegetable matrices has been developed and validated, including detection, identification and quantification of the analytes. To this aim, several food matrices were selected: high water content (apples, tomatoes and carrots), high acid content (oranges) and high oil content (olives) samples. The well known QuEChERS procedure was applied for extraction of pesticides, and matrix-matched calibration using relative responses versus internal standard was used for quantification. The sample extracts were analyzed by GC-TOF MS. Up to five ions using narrow window (0.02 Da)-extracted ion chromatograms at the expected retention time were monitored using a target processing method. The most abundant ion was used for quantification while the remaining ones were used for confirmation of the analyte identity. Method validation was carried out for 55 analytes in the five sample matrices tested at three concentrations (0.01, 0.05 and 0.5 mg/kg). Most recoveries were between 70% and 120% with relative standard deviations (RSDs) lower than 20% at 0.05 and 0.5mg/kg. At 0.01 mg/kg, roughly half of the pesticides could be satisfactorily validated due to sensitivity limitations of GC-TOF MS, which probably affected the ion ratios used for confirmation of identity. In the case of olive samples, results were not satisfactory due to the high complexity of the matrix. An advantage of TOF MS is the possibility to perform a non-target investigation in the samples by application of a deconvolution software, without any additional injection being required. Accurate-mass full-spectrum acquisition in TOF MS provides useful information for analytes identification, and has made feasible in this work the discovery of non-target imazalil, fluoranthene and pyrene in some of the samples analyzed. PMID:22608778

Cervera, M I; Portolés, T; Pitarch, E; Beltrán, J; Hernández, F

2012-06-29

279

Comparison of ZnS semiconductor nanoparticles capped with various functional groups as the matrix and affinity probes for rapid analysis of cyclodextrins and proteins in surface-assisted laser desorption/ionization time-of-flight mass spectrometry.  

PubMed

Zinc sulfide (ZnS) semiconductor nanoparticles (NPs) capped with a variety of functional groups including bare ZnS NPs, 3-mercaptopropanoic acid (ZnS-3-MPA), sodium citrate (ZnS-citrate), cysteamine (ZnS-Cys), and 2-mercaptoethane sulfonate (ZnS-2-MES) have been investigated as the matrix and affinity probes for analysis of alpha-, beta-, and gamma-cyclodextrins (CDs), ubiquitin, and insulin in biological samples by using surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF-MS). Various parameters that would influence the ionization efficiency and sensitivity of these ZnS NPs in SALDI-TOF-MS were examined including the effect of capping agents, sample pH, ion abundance, and concentration of ZnS NPs. Among these ZnS NPs, our results have demonstrated that ZnS-3-MPA exhibited the highest efficiency toward CDs, ubiquitin, and insulin for high-sensitivity detection in SALDI-TOF-MS. The detection limits were 20-55 nM for CDs, 91 nM for ubiquitin, and 85 nM for insulin. The applicability of the present method is demonstrated by detection of ubiquitin-like proteins in oyster mushroom and also in the analysis of analytes in biological samples such as human urine and plasma. To our best knowledge, this is the first time semiconductor NPs were used as the matrix and affinity probes for high-sensitivity detection of organic and biomolecules in SALDI-TOF-MS. This approach exhibits the advantages of being simple, rapid, efficient, and straightforward for direct analysis of organic and biological samples in SALDI-TOF-MS without the need for time-consuming separation processes, tedious washing steps, or further laborious purification. In addition, it also can provide a sensitive and reliable quantitative assay for small- and large-molecule analysis with the detectable mass up to 8500 Da. We believe that this novel ZnS nanoprobe is simple, efficient, lower cost (compared with Au, Ag, and Pt NPs), fast, and with the potential for high-throughput analysis in SALDI-TOF-MS. PMID:18991387

Kailasa, Suresh Kumar; Kiran, Kamatam; Wu, Hui-Fen

2008-12-15

280

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

281

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

282

Quantitative biomedical mass spectrometry  

NASA Astrophysics Data System (ADS)

The scope of this contribution is an illustration of the capabilities of isotope dilution mass spectrometry (IDMS) for quantification of target substances in the biomedical field. After a brief discussion of the general principles of quantitative MS in biological samples, special attention will be paid to new technological developments or trends in IDMS from selected examples from the literature. The final section will deal with the use of IDMS for accuracy assessment in clinical chemistry. Methodological aspects considered crucial for avoiding sources of error will be discussed.

de Leenheer, Andrép; Thienpont, Linda M.

1992-09-01

283

Application of sequential paired covariance to capillary electrophoresis electrospray ionization time-of-flight mass spectrometry: Unraveling the signal from the noise in the electropherogram  

SciTech Connect

The combination of capillary electrophoresis (CE) with electrospray ionization (ESI) time-of-flight mass spectrometry (TOF-MS) has recently been demonstrated. When CE is combined with TOF-MS using an electrospray interface, the method provides fast, high-resolution separations with rapid mass analysis and the potential for very high sensitivity. In analyzing the data, one first reconstructs an electropherogram from the data set and then identifies peaks in the mass spectra. The mass spectra corresponding to the peaks in the electropherogram are then inspected to enable solute identification. However, background noise often prevents detection of peaks in the reconstructed electropherogram, thus interfering with the analysis. In this work we demonstrate alternative electropherogram reconstruction techniques that enhance its signal-to-noise ratio, allowing more immediate identification of the number of components in a mixture and their corresponding retention times. The techniques described here should also be adaptable for on-line analysis of CE-ESI-TOF data and the combination with other separation techniques coupled to mass spectrometry (e.g., LC/MS), as well as any multichannel detection scheme. 21 refs., 4 figs., 1 tab.

Muddiman, D.C.; Rockwood, A.L.; Gao, Q.; Severs, J.C.; Udseth, H.R.; Smith, R.D. [Pacific Northwest Lab., Richland, WA (United States); Proctor, A. [GOOGLY Enterprises, Pittsburgh, PA (United States)

1995-12-01

284

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...

285

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

286

Application of MALDI-TOF mass spectrometry in screening and diagnostic research.  

PubMed

During the last years, mass spectrometry has revolutionised protein biochemistry and has advanced to a superior tool for the identification and detailed analysis of peptides and proteins. The high throughput allowed by some mass spectrometry platforms has enabled the important step from analysis of individual proteins to proteomics. Recently, an additional field of mass spectrometry applications has emerged - namely screening and diagnostic research. In contrast to protein identification, screening applications have to detect analyte molecules of defined molecular weights which can be calculated beforehand, for example by means of chemical structures. Here, the accuracy and sensitivity of mass spectrometry has to be combined with the requirements of high-throughput analyses, in particular speed and automation. These criteria are especially fulfilled by state of the art matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) instruments. The first high throughput screening (HTS) application proved to be genotyping of single nucleotide polymorphisms. The same principle was later applied for several quality control issues, for example for oligonucleotides, peptide or compound libraries. This development has culminated in the screening and profiling of complex biomarker patterns in clinical proteomics to detect a molecular fingerprint for specific diseases in biological samples. Thus, mass spectrometry based methods are expected to enable a very early diagnosis of diseases with minimally invasive methods of investigation. This type of high end screening application has the potential to revolutionise the early diagnosis of many diseases. Here, we give an overview of the application of mass spectrometry in the fields of screening and diagnostic research. PMID:16101460

Pusch, W; Kostrzewa, M

2005-01-01

287

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

288

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

289

Rapid identification and classification of Mycobacterium spp. using whole-cell protein barcodes with matrix assisted laser desorption ionization time of flight mass spectrometry in comparison with multigene phylogenetic analysis.  

PubMed

The need of quick diagnostics and increasing number of bacterial species isolated necessitate development of a rapid and effective phenotypic identification method. Mass spectrometry (MS) profiling of whole cell proteins has potential to satisfy the requirements. The genus Mycobacterium contains more than 154 species that are taxonomically very close and require use of multiple genes including 16S rDNA for phylogenetic identification and classification. Six strains of five Mycobacterium species were selected as model bacteria in the present study because of their 16S rDNA similarity (98.4-99.8%) and the high similarity of the concatenated 16S rDNA, rpoB and hsp65 gene sequences (95.9-99.9%), requiring high identification resolution. The classification of the six strains by MALDI TOF MS protein barcodes was consistent with, but at much higher resolution than, that of the multi-locus sequence analysis of using 16S rDNA, rpoB and hsp65. The species were well differentiated using MALDI TOF MS and MALDI BioTyper™ software after quick preparation of whole-cell proteins. Several proteins were selected as diagnostic markers for species confirmation. An integration of MALDI TOF MS, MALDI BioTyper™ software and diagnostic protein fragments provides a robust phenotypic approach for bacterial identification and classification. PMID:22284888

Wang, Jun; Chen, Wen Feng; Li, Qing X

2012-02-24

290

End-Group Characterization of Poly(O-benzyl-L-tyrosine) by NALDI-TOF MS  

SciTech Connect

The primary amine initiated polymerization of N-carboxyanhydrides of amino acids (NCAs) has been proposed to proceed by two mechanisms: normal amine mechanism and activated monomer mechanism. Recently, Hadjichristidis et al. showed that high vacuum techniques could be employed to synthesize poly(amino acid)s initiated with primary amines exclusively via the normal amine mechanism. Unfortunately, no end group characterization was reported. Herein we report the end group characterization of the amine-initiated polymerization of the NCA of O-benzyl-L-tyrosine by MALDI-TOF MS and NALDI TM-TOF MS. We show that when synthesized via high vacuum techniques the reaction proceeds exclusively by the normal amine mechanism. The activated monomer mechanism is detected in samples prepared by less rigorous techniques.

Pickel, Deanna L [ORNL; Messman, Jamie M [ORNL; Politakos, Nikolaos [ORNL; Avgeropoulos, Apostolos [ORNL

2009-01-01

291

SELDI-TOF-MS ProteinChip Array Profiling of Tears from Patients with Dry Eye  

Microsoft Academic Search

METHODS. Patients with dry eye (DRY, n 88) and healthy subjects (CTRL, n 71) were examined. Their tear proteins were analyzed using SELDI-TOF-MS ProteinChip Arrays with three different chromatographic surfaces (CM10 cation ex- change, Q10 anion exchange, and H50 reversed-phase) pre- pared by means of a laboratory liquid-handling robotic work- station. The data were analyzed by multivariate statistical techniques and

Franz H. Grus; Vladimir N. Podust; Kai Bruns; Karl Lackner; Siyu Fu; Enrique A. Dalmasso; Anton Wirthlin; Norbert Pfeiffer

2005-01-01

292

Improved Mass Spectrometry Assay For Plasma Hepcidin: Detection and Characterization of a Novel Hepcidin Isoform  

PubMed Central

Mass spectrometry (MS)-based assays for the quantification of the iron regulatory hormone hepcidin are pivotal to discriminate between the bioactive 25-amino acid form that can effectively block the sole iron transporter ferroportin and other naturally occurring smaller isoforms without a known role in iron metabolism. Here we describe the design, validation and use of a novel stable hepcidin-25+40 isotope as internal standard for quantification. Importantly, the relative large mass shift of 40 Da makes this isotope also suitable for easy-to-use medium resolution linear time-of-flight (TOF) platforms. As expected, implementation of hepcidin-25+40 as internal standard in our weak cation exchange (WCX) TOF MS method yielded very low inter/intra run coefficients of variation. Surprisingly, however, in samples from kidney disease patients, we detected a novel peak (m/z 2673.9) with low intensity that could be identified as hepcidin-24 and had previously remained unnoticed due to peak interference with the formerly used internal standard. Using a cell-based bioassay it was shown that synthetic hepcidin-24 was, like the -22 and -20 isoforms, a significantly less potent inducer of ferroportin degradation than hepcidin-25. During prolonged storage of plasma at room temperature, we observed that a decrease in plasma hepcidin-25 was paralleled by an increase in the levels of the hepcidin-24, -22 and -20 isoforms. This provides first evidence that all determinants for the conversion of hepcidin-25 to smaller inactive isoforms are present in the circulation, which may contribute to the functional suppression of hepcidin-25, that is significantly elevated in patients with renal impairment. The present update of our hepcidin TOF MS assay together with improved insights in the source and preparation of the internal standard, and sample stability will further improve our understanding of circulating hepcidin and pave the way towards further optimization and standardization of plasma hepcidin assays. PMID:24124495

Laarakkers, Coby M. M.; Wiegerinck, Erwin T.; Klaver, Siem; Kolodziejczyk, Maria; Gille, Hendrik; Hohlbaum, Andreas M.

2013-01-01

293

Improved mass spectrometry assay for plasma hepcidin: detection and characterization of a novel hepcidin isoform.  

PubMed

Mass spectrometry (MS)-based assays for the quantification of the iron regulatory hormone hepcidin are pivotal to discriminate between the bioactive 25-amino acid form that can effectively block the sole iron transporter ferroportin and other naturally occurring smaller isoforms without a known role in iron metabolism. Here we describe the design, validation and use of a novel stable hepcidin-25(+40) isotope as internal standard for quantification. Importantly, the relative large mass shift of 40 Da makes this isotope also suitable for easy-to-use medium resolution linear time-of-flight (TOF) platforms. As expected, implementation of hepcidin-25(+40) as internal standard in our weak cation exchange (WCX) TOF MS method yielded very low inter/intra run coefficients of variation. Surprisingly, however, in samples from kidney disease patients, we detected a novel peak (m/z 2673.9) with low intensity that could be identified as hepcidin-24 and had previously remained unnoticed due to peak interference with the formerly used internal standard. Using a cell-based bioassay it was shown that synthetic hepcidin-24 was, like the -22 and -20 isoforms, a significantly less potent inducer of ferroportin degradation than hepcidin-25. During prolonged storage of plasma at room temperature, we observed that a decrease in plasma hepcidin-25 was paralleled by an increase in the levels of the hepcidin-24, -22 and -20 isoforms. This provides first evidence that all determinants for the conversion of hepcidin-25 to smaller inactive isoforms are present in the circulation, which may contribute to the functional suppression of hepcidin-25, that is significantly elevated in patients with renal impairment. The present update of our hepcidin TOF MS assay together with improved insights in the source and preparation of the internal standard, and sample stability will further improve our understanding of circulating hepcidin and pave the way towards further optimization and standardization of plasma hepcidin assays. PMID:24124495

Laarakkers, Coby M M; Wiegerinck, Erwin T; Klaver, Siem; Kolodziejczyk, Maria; Gille, Hendrik; Hohlbaum, Andreas M; Tjalsma, Harold; Swinkels, Dorine W

2013-01-01

294

Rapid Burkholderia pseudomallei identification and antibiotic resistance determination by bacteriophage amplification and MALDI-TOF MS  

PubMed Central

Phage amplification detected by MALDI-TOF MS was investigated for rapid and simultaneous Burkholderia pseudomallei identification and ceftazidime resistance determination. B. pseudomallei ceftazidime susceptible and resistant ?purM mutant strains Bp82 and Bp82.3 were infected with broadly targeting B. pseudomallei phage ?X216 and production of the m/z 37.6 kDa phage capsid protein observed by MALDI-TOF MS over the course of 3 h infections. This allowed for repoducible phage-based bacterial ID within 2 h of the onset of infection. MALDI-TOF MS-measured time to detection correlated with in silico modeling, which predicted an approximate 2 h detection time. Ceftazidime susceptible strain Bp82, while detectable in the absence of the drug, owing to the reliance of phage amplification on a viable host, was not detectable when 10 ?g/mL ceftazidime was added at the onset of infection. In contrast, resistant strain Bp82.3 was detected in the same 2 h timeframe both with and without the addition of ceftazidime. PMID:25050191

Cox, Christopher R; Saichek, Nicholas R; Schweizer, Herbert P; Voorhees, Kent J

2014-01-01

295

Rapid, sensitive and simultaneous determination of fluorescence-labeled designated substances controlled by the Pharmaceutical Affairs Law in Japan by ultra-performance liquid chromatography coupled with electrospray-ionization time-of-flight mass spectrometry.  

PubMed

A simultaneous determination method based on ultra-performance liquid chromatography (UPLC) with fluorescence (FL) detection and electrospray-ionization time-of-flight mass spectrometry (ESI-TOF-MS) was developed for 16 "designated substances" (Shitei-Yakubutsu) controlled by the Pharmaceutical Affairs Law in Japan. These substances were first labeled with 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole at 60 degrees C for 2 h in 0.1 M borax (pH 9.3). The resulting fluorophores were well separated by reversed-phase chromatography using an Acquity UPLC BEH C(18) column (1.7 microm, 100 mm x 2.1 mm i.d.) by isocratic elution with a mixture of water and acetonitrile-methanol (20:80) containing 0.1% formic acid. The separated derivatives were sensitively detected by both FL and TOF-MS. However, the determination of several designated substances by FL detection showed interference from endogenous substances in biological samples. Therefore, the determination in real samples was carried out by a combination of UPLC separation and ESI-TOF-MS detection. The structures of the designated substances were identified from the protonated-molecular ions [M+H](+) obtained from the TOF-MS measurement. The calibration curves obtained from the peak area ratios of the internal standard (I.S.), i.e., 3-phenyl-1-propylamine, and the designated substances versus the injection amounts showed good linearity. The limits of detection (S/N = 3) and the limits of quantification (S/N = 10) in 0.1 mL of human plasma and urine for the present method were 0.30-150 pmol and 1.0-500 pmol, respectively. Good accuracy and precision (according to intraday and interday assays) were also obtained with the present procedure. This method was applied to analyses of human plasma, urine and real products. PMID:19756548

Min, Jun Zhe; Hatanaka, Suguru; Toyo'oka, Toshimasa; Inagaki, Shinsuke; Kikura-Hanajiri, Ruri; Goda, Yukihiro

2009-11-01

296

Unusual Analyte-Matrix Adduct Ions and Mechanism of Their Formation in MALDI TOF MS of Benzene-1,3,5-Tricarboxamide and Urea Compounds  

NASA Astrophysics Data System (ADS)

Analyte-matrix adducts are normally absent under typical matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) conditions. Interestingly, though, in the analysis of several types of organic compounds synthesized in our laboratory, analyte-matrix adduct ion peaks were always recorded when common MALDI matrices such as 4-hydroxy-?-cyanocinnamic acid (CHCA) were used. These compounds are mainly those with a benzene-1,3,5-tricarboxamide (BTA) or urea moiety, which are important building blocks to make new functional supramolecular materials. The possible mechanism of the adduct formation was investigated. A shared feature of the compounds studied is that they can form intermolecular hydrogen bonding with matrices like CHCA. The intermolecular hydrogen bonding will make the association between analyte ions and matrix molecules stronger. As a result, the analyte ions and matrix molecules in MALDI clusters will become more difficult to be separated from each other. Furthermore, it was found that analyte ions were mainly adducted with matrix salts, which is probably due to the much lower volatility of the salts compared with that of their corresponding matrix acids. It seems that the analyte-matrix adduct formation for our compounds are caused by the incomplete evaporation of matrix molecules from the MALDI clusters because of the combined effects of enhanced intermolecular interaction between analyte-matrix and of the low volatility of matrix salts. Based on these findings, strategies to suppress the analyte-matrix adduction are briefly discussed. In return, the positive results of using these strategies support the proposed mechanism of the analyte-matrix adduct formation.

Lou, Xianwen; Fransen, Michel; Stals, Patrick J. M.; Mes, Tristan; Bovee, Ralf; van Dongen, Joost J. L.; Meijer, E. W.

2013-09-01

297

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

298

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

299

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.; Lefleche, 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.; Lecuyer, H.; Beretti, J.-L.; Vay, C.; Berche, P.; Ferroni, A.; Nassif, X.

2012-01-01

300

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

301

Evaluation of matrix-assisted laser desorption/ionization mass spectrometry for second-generation lignin analysis.  

PubMed

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

302

Application Note PrepMS: TOF MS Data Graphical Preprocessing Tool  

E-print Network

tool that enables researchers to easily prepare time-of-flight mass spectrometry data for analysis://sourceforge.net/projects/prepms Contact: ykarpi@mdanderson.org INTRODUCTION Time-of-flight (TOF) mass spectrometry (MS) data is commonly: spectral calibration, including signal interpolation to impose a common time scale across spectra; spectral

Morris, Jeffrey S.

303

Capillary isotachophoresis mass spectrometry  

SciTech Connect

The on-line combination of capillary isotachophoresis (CITP) with mass spectrometry is demonstrated for the first time. The CITP/MS interface is based upon electrospray ionization and is identical with that developed previously for capillary zone electrophoresis (CZE)/MS. Separations were conducted in untreated 100 ..mu..m i.d. fused silica capillaries having lengths of 0.6-2.5 m, at voltages up to 35 kV. The method involves elution of the leading electrolyte to the electrospray source followed by a sequence of separated analyte bands (if sufficient time is provided for development) and, finally, the trailing electrolyte. The CITP/MS was demonstrated to allow very high resolution separations of quaternary phosphonium ions and other ionic substances having very small differences in electrophoretic mobilities. Nearly ideal band shapes are obtained in most separations despite the presence of electroosmotic flow. The potential for application to very dilute sample solutions is demonstrated by detection of analytes having 10/sup /minus/9/ M concentrations, with signal to noise ratios of approximately 10/sup 2/ for some components, which as at least 2 orders of magnitude better than CZE/MS. CITP/MS appears to be an attractive complement to CZE/MS for dilute (low ionic strength) solutions since much greater sample sizes can be addressed without loss of efficiency.

Udseth, H.R.; Loo, J.A.; Smith, R.D.

1989-02-01

304

Novel strategy for typing Mycoplasma pneumoniae isolates by use of matrix-assisted laser desorption ionization-time of flight mass spectrometry coupled with ClinProTools.  

PubMed

The typing of Mycoplasma pneumoniae mainly relies on the detection of nucleic acid, which is limited by the use of a single gene target, complex operation procedures, and a lengthy assay time. Here, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) coupled to ClinProTools was used to discover MALDI-TOF MS biomarker peaks and to generate a classification model based on a genetic algorithm (GA) to differentiate between type 1 and type 2 M. pneumoniae isolates. Twenty-five M. pneumoniae strains were used to construct an analysis model, and 43 Mycoplasma strains were used for validation. For the GA typing model, the cross-validation values, which reflect the ability of the model to handle variability among the test spectra and the recognition capability value, which reflects the model's ability to correctly identify its component spectra, were all 100%. This model contained 7 biomarker peaks (m/z 3,318.8, 3,215.0, 5,091.8, 5,766.8, 6,337.1, 6,431.1, and 6,979.9) used to correctly identify 31 type 1 and 7 type 2 M. pneumoniae isolates from 43 Mycoplasma strains with a sensitivity and specificity of 100%. The strain distribution map and principle component analysis based on the GA classification model also clearly showed that the type 1 and type 2 M. pneumoniae isolates can be divided into two categories based on their peptide mass fingerprints. With the obvious advantages of being rapid, highly accurate, and highly sensitive and having a low cost and high throughput, MALDI-TOF MS ClinProTools is a powerful and reliable tool for M. pneumoniae typing. PMID:24920781

Xiao, Di; Zhao, Fei; Zhang, Huifang; Meng, Fanliang; Zhang, Jianzhong

2014-08-01

305

Matrix-Assisted Laser Desorption Ionization: Time of Flight Mass Spectrometry-Identified Models for Detection of ESBL-Producing Bacterial Strains.  

PubMed

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 and 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

306

Rapid identification of microorganisms by mass spectrometry: improved performance by incorporation of in-house spectral data into a commercial database.  

PubMed

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is increasingly used as a microbial diagnostic method for species identification of pathogens. However, MALDI-TOF identification of bacteria at the species level remains unsatisfactory, with the major problem being an incomplete database that still needs refinement and expansion. Augmentation of the original MALDI BioTyper 2.0 (Bruker) database by incorporating mass spectra obtained in-house from clinical isolates may increase the identification rate at the species level. We conducted a prospective study to assess whether the augmented database can improve the performance of MALDI-TOF MS for routine identification of species. Cluster analyses revealed distinct differences in MS spectral profiles of clinical isolates obtained in our hospital and those of ATCC strains in the Bruker database. In the first part of the study, which was performed over 3 weeks, 259 bacterial isolates were subjected to analysis by MALDI-TOF MS, and MS spectra of 229 successfully identified isolates (49 species) were incorporated into the original database to give the augmented Bruker-Chiba database. In a second separate analysis, the concordance of identification of 498 clinical isolates of the 49 species with conventional methods was 87.1% (434/498) with the commercial Bruker database and 98.0% (488/498) using the Bruker-Chiba database. These results indicate that refinement of a commercial database can be achieved relatively easy and effectively by incorporating MS spectra of clinical isolates obtained in a clinical laboratory. PMID:22200929

Sogawa, Kazuyuki; Watanabe, Masaharu; Sato, Kenichi; Segawa, Syunsuke; Miyabe, Akiko; Murata, Syota; Saito, Tomoko; Nomura, Fumio

2012-06-01

307

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

308

Identification of carbohydrates by matrix-free material-enhanced laser desorption/ionisation mass spectrometry.  

PubMed

Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) is a sensitive mass spectrometric technique which utilises acidic materials as matrices for laser energy absorption, desorption and ionisation of analytes. These matrix materials produce background signals particularly in the low-mass range and make the detection and identification of small molecules difficult and nearly impossible. To overcome this problem this paper introduces matrix-free material-enhanced laser desorption/ionisation mass spectrometry (mf-MELDI-MS) for the screening and analysis of small molecules such as carbohydrates. For this purpose, 4,4'-azo-dianiline was immobilised on silica gel enabling the absorption of laser energy sufficient for successful desorption and ionisation of low molecular weight compounds. The particle and pore sizes, the solvent system for suspension and the sample preparation procedures have been optimised. The newly synthesised MELDI material delivered excellent spectra with regard to signal-to-noise ratio and detection sensitivity. Finally, wheat straw degradation products and Salix alba L. plant extracts were analysed proving the high performance and excellent behaviour of the introduced material. PMID:17654466

Hashir, Muhammad Ahsan; Stecher, Guenther; Bakry, Rania; Kasemsook, Saowapak; Blassnig, Bernhard; Feuerstein, Isabel; Abel, Gudrun; Popp, Michael; Bobleter, Ortwin; Bonn, Guenther K

2007-01-01

309

Characterization of proteins utilized in the desulfurization of petroleum products by matrix-assisted laser desorption ionization time-of-flight mass spectrometry  

SciTech Connect

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 from Rhodococcus sp. strain IGTS8 that produce three of the four enzymes under study had been previously reported with a discrepancy in residue assignments for one of the enzymes, dsz-C. The use of proteolytic digests followed by MALDI/TOF/MS with delayed extraction in the reflected-ion mode provided sequence-specific information with mass accuracies exceeding 40 ppm over a range of masses and signal-to-noise values. Peptide mapping of >80% of the residues was accomplished for all four proteins. The use of PSD established the true sequence for dsz-C, resolving the discrepancy in the literature. A posttranslational loss of N-terminal methionine was observed for each of the four proteins in linear MALDI/MS and was reconfirmed by peptide mapping for three of the proteins.

Wolf, B.P.; Sumner, L.W.; Shields, S.J.; Russell, D.H. [Texas A and M Univ., College Station, TX (United States). Dept. of Chemistry] [Texas A and M Univ., College Station, TX (United States). Dept. of Chemistry; Nielsen, K.; Gray, K.A. [Energy Biosystems Corp., The Woodlands, TX (United States)] [Energy Biosystems Corp., The Woodlands, TX (United States)

1998-07-01

310

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

311

Breakthrough bacteremia due to Clostridium tertium in a patient with neutropenic fever, and identification by MALDI-TOF mass spectrometry.  

PubMed

Clostridium tertium is rare in a human clinical specimen and its pathogenicity is often uncertain. However, the organism has been increasingly recognized as a cause of bacteremia and other infections in immunocompromised patients, especially those with hematologic malignancies. The diagnosis and treatment of C. tertium are difficult due to its growth pattern, micromorphology, and antibiotic resistance. The organism can easily be misidentified as Gram-positive aerobic rods such as Bacillus species, usually considered as a contaminant. Furthermore, it is not covered by empirical treatment with many broad-spectrum antibiotics. Here we report a case of breakthrough bacteremia due to C. tertium that occurred in a patient with acute leukemia and neutropenic fever, who was treated with an empirical regimen of ceftazidime and amikacin. The bacterium was rapidly identified by new mass spectrometry technology (MALDI-TOF MS) and the patient recovered under meropenem and vancomycin treatment, without complications. PMID:23823278

Salvador, Francisco; Porte, Lorena; Durán, Luisa; Marcotti, Alejandra; Pérez, Jorge; Thompson, Luis; Noriega, Luis Miguel; Lois, Vivianne; Weitzel, Thomas

2013-11-01

312

Detection of hepatitis B virus DNA in serum samples via nested PCR and MALDI-TOF mass spectrometry.  

PubMed

In a blind study, nested polymerase chain reaction (PCR) was performed with control DNA and DNA preparations from serum samples of six patients. The detection limit was determined to be 100 molecules of template in 1 ml of serum. Hepatitis B virus (HBV) related products of nested PCR were purified by ultrafiltration and immobilisation on streptavidin coated magnetic beads. The immobilized PCR products were denatured from the beads and analyzed via matrix assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry. The results of MALDI-TOF MS analysis were in agreement with the results obtained by polyacrylamide gel electrophoresis (PAGE) and with the data obtained by serological analysis. The detection strategy introduced here has a high potential for automation and represents a fast and reliable method of detection for HBV DNA in serum without the need for time consuming gel electrophoresis and labeling or hybridization procedures. PMID:8931993

Jurinke, C; Zöllner, B; Feucht, H H; Jacob, A; Kirchhübel, J; Lüchow, A; van den Boom, D; Laufs, R; Köster, H

1996-09-01

313

[Application of Surface Enhanced Laser Desorption/Ionization Time-of-Flight Mass Spectrometry in the Diagnosis of Leukemia].  

PubMed

This study was purposed to find new biomarkers and to establish protein finger print model for diagnosis of leukemia. A total of 40 leukemia samples and 37 healthy control samptes were tested by surface enhance laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF- MS). The data of spectra were analyzed by bioinformatics tools like Biomarker Patterns 5.0 and discriminant analysis to establish diagnostic mode1. The results showed that 22 protein features were stably detected by protein fingerprint, The detective model combined with 3 biomarkers (m/z 4650, 8609 and 11660) could differentiate leukemia with sensitivity of 97.5% (39/40) and specificity of 91.9%(34/37). It is concluded that the detective model established by 3 protein features may be a novel method for diagnosis of leukemia. PMID:25338571

Huang, Hua; Chen, Lin-Xing; Lin, Mei-Shan; Huang, Jing-Yu

2014-09-01

314

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, Lukasz; Banach, Tomasz; Bartnicki, Micha?; Winiarczyk, Dagmara; Lyp, Pawe?; Winiarczyk, Stanis?aw

2014-11-01

315

Linear electric field mass spectrometry  

DOEpatents

A mass spectrometer and methods for mass spectrometry. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field.

McComas, David J. (Los Alamos, NM); Nordholt, Jane E. (Los Alamos, NM)

1992-01-01

316

Linear electric field mass spectrometry  

DOEpatents

A mass spectrometer and methods for mass spectrometry are described. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field. 8 figs.

McComas, D.J.; Nordholt, J.E.

1992-12-01

317

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

318

The QUISTOR as a pulsed-extraction source for time-of-flight mass spectrometry of VOCs in air  

SciTech Connect

Recently, the authors have been developing the ion trap/time-of-flight mass spectrometer (IT/TOF-MS) as a new instrument for real-time air analysis. The ion trap is an attractive pulsed-extraction source for TOF-MS because of its ion storage capability and its potential for high extraction efficiencies. In the IT/TOF-MS ion trap the entire ion cloud is extracted toward the exit endcap, as compared to 50% in an ion trap mass spectrometer. Moreover, the ion trap pulsed-extraction source can tolerate high background pressures and excessive space charge. The work presented here focuses on the development of the ion trap to improve the overall performance of the IT/TOF-MS used for air monitoring. A number studies have been performed to determine the best conditions for extraction of the ion cloud with the proper spatial and velocity distributions for focusing in the TOF-MS. Results from these investigations have led to improvements in ion trap operation. Detection limits are generally in the low to sub-ppb (V/V) range for analysis between times 10 and 100 ms. Resolution exceeds 2000 m/{Delta}m at FWHM. Mass accuracy is routinely 0.05% and scan-to-scan variations are less than 5%.

Chambers, D.M.; Thomas, S.W.; Grace, L.I.; Andresen, B.D. [Lawrence Livermore National Lab., CA (United States)

1995-12-31

319

Mass spectrometry. [in organic chemistry  

NASA Technical Reports Server (NTRS)

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 gas-phase ion chemistry as electron-impact ionization and decomposition, photoionization, field ionization and desorption, high-pressure mass spectrometry, ion cyclotron resonance, and isomerization reactions of organic ions. Applications of mass spectrometry are examined with respect to bio-oligomers and their constituents, biomedically important substances, microbiology, environmental organic analysis, and organic geochemistry.

Burlingame, A. L.; Shackleton, C. H. L.; Howe, I.; Chizhov, O. S.

1978-01-01

320

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

321

Characterization of environmental isolates of Enterococcus spp. by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.  

PubMed

Currently available bacterial source-tracking tools are often technically demanding, time consuming, and have limited accuracy in grouping isolates according to their respective sources. There is a need for the development of bacterial source-tracking tools that would allow for more rapid and accurate grouping of isolates by source. We examined the use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) for the characterization of environmental isolates of Enterococcus. Our main objectives were to develop sample preparation protocols for obtaining reproducible MALDI-TOF mass spectra from Enterococcus isolates and to evaluate methods of data analysis to maximize repeatability of the method and its ability to group isolates according to their respective sources. Our data showed that treatment of 21 Enterococcus isolates from seven unique sources with lysozyme for 20 h, followed by calculation of similarity coefficients using the Pearson product-moment correlation coefficient, facilitated a repeatability level of 91% as well as grouping by source for isolates obtained from several sources including human waste. Our data suggest that MALDI-TOF-MS-based fingerprinting of environmental isolates of Enterococcus has potential as a rapid and accurate bacterial source tracking (BST) tool, but requires further development, specifically regarding the time requirements needed for pre-treatment of isolates with lysozyme. PMID:17931682

Giebel, Rebecca A; Fredenberg, Weston; Sandrin, Todd R

2008-02-01

322

Base-specific fragmentation of amplified 16S rRNA genes analyzed by mass spectrometry: A tool for rapid bacterial identification  

PubMed Central

A rapid approach to the 16S rRNA gene (16S rDNA)-based bacterial identification has been developed that combines uracil-DNA-glycosylase (UDG)-mediated base-specific fragmentation of PCR products with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). 16S rDNA signature sequences were PCR-amplified from both cultured and as-yet-uncultured bacteria in the presence of dUTP instead of dTTP. These PCR products then were immobilized onto a streptavidin-coated solid support to selectively generate either sense or antisense templates. Single-stranded amplicons were subsequently treated with uracil-DNA-glycosylase to generate T-specific abasic sites and fragmented by alkaline treatment. The resulting fragment patterns were analyzed by MALDI-TOF MS. Mass signals of 16S rDNA fragments were compared with patterns calculated from published 16S rDNA sequences. MS of base-specific fragments of amplified 16S rDNA allows reliable discrimination of sequences differing by only one nucleotide. This approach is fast and has the potential for high-throughput identification as required in clinical, pharmaceutical, or environmental microbiology. In contrast to identification by MS of intact whole bacterial cells, this technique allows for the characterization of both cultured and as-yet-uncultured bacteria. PMID:11983869

von Wintzingerode, Friedrich; Böcker, Sebastian; Schlötelburg, Cord; Chiu, Norman H. L.; Storm, Niels; Jurinke, Christian; Cantor, Charles R.; Göbel, Ulf B.; van den Boom, Dirk

2002-01-01

323

A Two-stage Peak Alignment Algorithm for Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry-Based Metabolomics.  

PubMed

Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC/TOF-MS) has been applied to metabolomics analyses recently. However, retention time shifts in the two-dimensional gas chromatography will introduce difficulty to compare compound profiles obtained from multiple samples. In this work, a novel two-stage peak alignment algorithm has been developed for data analysis of GC×GC/TOF-MS. In the first stage, our algorithm detects and merges multiple peak entries of the same metabolite into one peak entry. After a z-score transformation of metabolite retention times, landmark peaks will be selected from all samples based on both two-dimensional retention times and mass spectrum similarity of fragment ions measured by Pearson's correlation coefficient. In the second stage, the original two-dimensional retention time shift will be corrected using a local linear fitting method. A progressive retention time map searching method is used to align peaks in all samples together based on the parameters optimized in the first stage. Our algorithm can avoid defining a threshold of retention time window and spectrum similarity, which is very difficult for the users since the experimental condition is always changed in different experimental runs, even for the repeat experiments. The experimental results show that our algorithm can work well in peak alignment from real biological samples, which is very important for the further analysis. PMID:24688732

Wang, Bing

2013-01-01

324

Matrix-assisted laser desorption/ionization-time of flight-mass spectrometry profiling of trace constituents of condom lubricants in the presence of biological fluids.  

PubMed

The use of condoms in sexual assault cases has become increasingly common due to the heightened awareness of the use of DNA as evidence in criminal investigations. The ability to identify and differentiate the polymers and additives found in lubricant residues can provide investigators leads and insights as to the perpetrator of a sexual assault. Matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) is ideal for detecting condom lubricants and additives; the instrument is capable of surveying analytes across a wide mass range and is a preferred technique for the analysis of polymers. Three MALDI-TOF-MS methods directed toward the detection and differentiation of condom and personal lubricant residues, as well as their mixtures with biological fluids, were developed and compared: (a) a sample premixed with aqueous matrix; (b) a sample premixed with an ionic liquid matrix; and (c) a layering method that incorporates a cationization reagent. Of the three, the layered method that utilized sodium chloride as a cationization reagent showed the best sensitivity and selectivity. This method allowed for the segregation of the various lubricant formulas into a discrete number of groups. Infrared spectroscopy was used to support and clarify the MALDI data. Principal component analysis was used to further demonstrate the ability of this method to segregate various lubricant types into a limited number of classes. Additionally, lubricant residues could be detected in the presence of biological fluids down to a fraction of a percent. PMID:20832207

Spencer, Sandra E; Kim, Sin Young; Kim, Seoung Bum; Schug, Kevin A

2011-04-15

325

Improved sample preparation of glyphosate and methylphosphonic acid by EPA method 6800A and time-of-flight mass spectrometry using novel solid-phase extraction.  

PubMed

The employment of chemical weapons by rogue states and/or terrorist organizations is an ongoing concern in the United States. The quantitative analysis of nerve agents must be rapid and reliable for use in the private and public sectors. Current methods describe a tedious and time-consuming derivatization for gas chromatography-mass spectrometry and liquid chromatography in tandem with mass spectrometry. Two solid-phase extraction (SPE) techniques for the analysis of glyphosate and methylphosphonic acid are described with the utilization of isotopically enriched analytes for quantitation via atmospheric pressure chemical ionization-quadrupole time-of-flight mass spectrometry (APCI-Q-TOF-MS) that does not require derivatization. Solid-phase extraction-isotope dilution mass spectrometry (SPE-IDMS) involves pre-equilibration of a naturally occurring sample with an isotopically enriched standard. The second extraction method, i-Spike, involves loading an isotopically enriched standard onto the SPE column before the naturally occurring sample. The sample and the spike are then co-eluted from the column enabling precise and accurate quantitation via IDMS. The SPE methods in conjunction with IDMS eliminate concerns of incomplete elution, matrix and sorbent effects, and MS drift. For accurate quantitation with IDMS, the isotopic contribution of all atoms in the target molecule must be statistically taken into account. This paper describes two newly developed sample preparation techniques for the analysis of nerve agent surrogates in drinking water as well as statistical probability analysis for proper molecular IDMS. The methods described in this paper demonstrate accurate molecular IDMS using APCI-Q-TOF-MS with limits of quantitation as low as 0.400 mg/kg for glyphosate and 0.031 mg/kg for methylphosphonic acid. PMID:22359323

Wagner, Rebecca; Wetzel, Stephanie J; Kern, John; Kingston, H M Skip

2012-02-01

326

Mass Spectrometry in the Postgenomic Era  

E-print Network

Mass Spectrometry in the Postgenomic Era Brian T. Chait Laboratory for Mass Spectrometry reserved 0066-4154/11/0707-0239$20.00 Keywords cellular systems, proteomics, protein complexes, native mass spectrometry, lipidomics Abstract Mass spectrometry (MS) is rapidly becoming an essential tool for bi- ologists

Chait, Brian T.

327

Instrumentation for mass spectrometry: 1997  

SciTech Connect

All mass spectrometry experiments involve the manipulation of material, an interface with the mass spectrometer, ionization, ion manipulation/analysis, detection and data collection/reduction. Each of these elements involve instrumentation. The wide range of species now amenable to mass spectrometry and the diverse areas of physical science in which it plays a role have led to a seemingly unlimited array of instrumental combinations. However, only a limited number of mass analyzers, and their combinations, dominate. The dominant analyzers include time-of-flight, Fourier transform ion cyclotron resonance, the Paul trap, the mass filter, and the sector mass spectrometer. Why there are so few (or so many, depending upon one`s point of view) can be understood upon consideration of a set of mass analyzer figures of merit. These include mass resolution, mass accuracy, mass range, dynamic range, abundance sensitivity, precision, efficiency, speed, MS{sup n} capability, compatibility with the ionizer, cost, and size. The most appropriate form of mass spectrometry is determined by the priorities of the particular measurement placed on the various mass analyzer characteristics and the relative strengths of the analyzers in meeting the requirements. Each of the analyzer types has a unique set of figures of merit that makes it optimally suited for particular applications. This paper discusses these figures of merit, provides data illustrating recent developments for each analyzer type, and gives the figures of merit of each type of analyzer as they stand in 1997. 101 refs., 24 figs.

McLuckey, S.A.

1997-08-01

328

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  

Microsoft Academic Search

Toxic organophosphorus compounds (OPC), e.g., pesticides and nerve agents (NA), are known to phosphylate distinct endogenous\\u000a proteins in vivo and in vitro. OPC adducts of butyrylcholinesterase and albumin are considered to be valuable biomarkers for\\u000a retrospective verification of OPC exposure. Therefore, we have detected and identified novel adducts of human serum albumin\\u000a (HSA) by means of matrix-assisted laser desorption\\/ionization time-of-flight

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

2010-01-01

329

The use of HPTLC and Direct Analysis in Real Time-Of-Flight Mass Spectrometry (DART-TOF-MS) for rapid analysis of degradation by oxidation and sonication of an azo dye  

E-print Network

are highly carcinogenic (Brown and De Vito, 1993). For instance, the anionic dye, Methyl red, is used in paper printing and textile dyeing ( Lachheb et al., 2002), as well as in the food industry (Muthuraman

Paris-Sud XI, Université de

330

A Glossary for Mass Spectrometry  

NSDL National Science Digital Library

This useful article from the journal Mass Spectrometry features a compilation of some of the more widely used terms that non-mass spectrometrists may encounter, and for which a simple definition would be helpful. The link will lead users to a PDF file which may be downloaded or viewed online.

Busch, Kenneth L.

2011-05-25

331

Coumarin tags for analysis of peptides by MALDI-TOF MS and MS/MS. 2. Alexa Fluor 350 tag for increased peptide and protein Identification by LC-MALDI-TOF/TOF MS.  

PubMed

The goal of this study was the development of N-terminal tags to improve peptide identification using high-throughput MALDI-TOF/TOF MS. Part 1 of the study was focused on the influence of derivatization on the intensities of MALDI-TOF MS signals of peptides. In part 2, various derivatization approaches for the improvement of peptide fragmentation efficiency in MALDI-TOF/TOF MS are explored. We demonstrate that permanent cation tags, while significantly improving signal intensity in the MS mode, lead to severe suppression of MS/MS fragmentation, making these tags unsuitable for high-throughput MALDI-TOF/TOF MS analysis. In the present work, it was found that labeling with Alexa Fluor 350, a coumarin tag containing a sulfo group, along with guanidation of epsilon-amino groups of Lys, could enhance unimolecular fragmentation of peptides with the formation of a high-intensity y-ion series, while the peptide intensities in the MS mode were not severely affected. LC-MALDI-TOF/TOF MS analysis of tryptic peptides from the SCX fractions of an E. coli lysate revealed improved peptide scores, a doubling of the total number of peptides, and a 30% increase in the number of proteins identified, as a result of labeling. Furthermore, by combining the data from native and labeled samples, confidence in correct identification was increased, as many proteins were identified by different peptides in the native and labeled data sets. Additionally, derivatization was found not to impair chromatographic behavior of peptides. All these factors suggest that labeling with Alexa Fluor 350 is a promising approach to the high-throughput LC-MALDI-TOF/TOF MS analysis of proteomic samples. PMID:15801742

Pashkova, Anna; Chen, Hsuan-Shen; Rejtar, Tomas; Zang, Xin; Giese, Roger; Andreev, Victor; Moskovets, Eugene; Karger, Barry L

2005-04-01

332

Simultaneous qualitative and quantitative analysis of phenolic acids and flavonoids for the quality control of Apocynum venetum L. leaves by HPLC-DAD-ESI-IT-TOF-MS and HPLC-DAD.  

PubMed

A reliable method based on high performance liquid chromatography-diode array detector-electrospray ionization-ion trap-time of flight-mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS) was developed for the identification of phenolic acids and flavonoids in Apocynum venetum L. leaves and its adulterant, Pocynum hendersonii (Hook. f.) Woodson leaves. A total of 21 compounds were identified or tentatively identified, including 4 phenolic acids and 17 flavonoids. 3-O-caffeoylquinic acid (3-CQA) and caffeic acid were detected for the first time in A. venetum leaves; 4-O-caffeoylquinic acid (4-CQA), 3-CQA, caffeic acid, quercetin-3-O-(6"-O-malonyl)-galactoside, quercetin-3-O-(6"-O-malonyl)-glucoside, kaempferol-3-O-(6"-O-malonyl)-glucoside, kaempferol-3-O-(6"-O-acetyl)-glucoside, and kaempferol-3-O-dihexoside were detected for the first time in P. hendersonii leaves. Cluster analysis was employed to analyze 24 batches of A. venetum leaves and 5 batches of P. hendersonii leaves collected from various regions in China. The analysis, which was based on the 21 compounds, indicated that profiles of these compounds were distinct between the two species, and among A. venetum leaf samples from different origins. 18 of these 21 compounds were selected as the markers and simultaneously analyzed by HPLC-DAD for the first time. The quantitative analytical method was validated and subsequently applied to the comprehensive quality evaluation of 24 batches of A. venetum leaves. PMID:23973760

An, Haijuan; Wang, Hong; Lan, Yuexiang; Hashi, Yuki; Chen, Shizhong

2013-11-01

333

Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Identification of Yeasts Is Contingent on Robust Reference Spectra  

PubMed Central

Background Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for yeast identification is limited by the requirement for protein extraction and for robust reference spectra across yeast species in databases. We evaluated its ability to identify a range of yeasts in comparison with phenotypic methods. Methods MALDI-TOF MS was performed on 30 reference and 167 clinical isolates followed by prospective examination of 67 clinical strains in parallel with biochemical testing (total n?=?264). Discordant/unreliable identifications were resolved by sequencing of the internal transcribed spacer region of the rRNA gene cluster. Principal Findings Twenty (67%; 16 species), and 24 (80%) of 30 reference strains were identified to species, (spectral score ?2.0) and genus (score ?1.70)-level, respectively. Of clinical isolates, 140/167 (84%) strains were correctly identified with scores of ?2.0 and 160/167 (96%) with scores of ?1.70; amongst Candida spp. (n?=?148), correct species assignment at scores of ?2.0, and ?1.70 was obtained for 86% and 96% isolates, respectively (vs. 76.4% by biochemical methods). Prospectively, species-level identification was achieved for 79% of isolates, whilst 91% and 94% of strains yielded scores of ?1.90 and ?1.70, respectively (100% isolates identified by biochemical methods). All test scores of 1.70–1.90 provided correct species assignment despite being identified to “genus-level”. MALDI-TOF MS identified uncommon Candida spp., differentiated Candida parapsilosis from C. orthopsilosis and C. metapsilosis and distinguished between C. glabrata, C. nivariensis and C. bracarensis. Yeasts with scores of <1.70 were rare species such as C. nivariensis (3/10 strains) and C. bracarensis (n?=?1) but included 4/12 Cryptococcus neoformans. There were no misidentifications. Four novel species-specific spectra were obtained. Protein extraction was essential for reliable results. Conclusions MALDI-TOF MS enabled rapid, reliable identification of clinically-important yeasts. The addition of spectra to databases and reduction in identification scores required for species-level identification may improve its utility. PMID:22022438

Pinto, Angie; Halliday, Catriona; Zahra, Melissa; van Hal, Sebastian; Olma, Tom; Maszewska, Krystyna; Iredell, Jonathan R.; Meyer, Wieland; Chen, Sharon C.-A.

2011-01-01

334

Direct Analysis and Identification of Pathogenic Lichtheimia Species by Matrix-Assisted Laser Desorption Ionization–Time of Flight Analyzer-Mediated Mass Spectrometry  

PubMed Central

Zygomycetes of the order Mucorales can cause life-threatening infections in humans. These mucormycoses are emerging and associated with a rapid tissue destruction and high mortality. The resistance of Mucorales to antimycotic substances varies between and within clinically important genera such as Mucor, Rhizopus, and Lichtheimia. Thus, an accurate diagnosis before onset of antimycotic therapy is recommended. Matrix-assisted laser desorption ionization (MALDI)–time of flight (TOF) mass spectrometry (MS) is a potentially powerful tool to rapidly identify infectious agents on the species level. We investigated the potential of MALDI-TOF MS to differentiate Lichtheimia species, one of the most important agents of mucormycoses. Using the Bruker Daltonics FlexAnalysis (version 3.0) software package, a spectral database library with m/z ratios of 2,000 to 20,000 Da was created for 19 type and reference strains of clinically relevant Zygomycetes of the order Mucorales (12 species in 7 genera). The database was tested for accuracy by use of 34 clinical and environmental isolates of Lichtheimia comprising a total of five species. Our data demonstrate that MALDI-TOF MS can be used to clearly discriminate Lichtheimia species from other pathogenic species of the Mucorales. Furthermore, the method is suitable to discriminate species within the genus. The reliability and robustness of the MALDI-TOF-based identification are evidenced by high score values (above 2.3) for the designation to a certain species and by moderate score values (below 2.0) for the discrimination between clinically relevant (Lichtheimia corymbifera, L. ramosa, and L. ornata) and irrelevant (L. hyalospora and L. sphaerocystis) species. In total, all 34 strains were unequivocally identified by MALDI-TOF MS with score values of >1.8 down to the generic level, 32 out of 34 of the Lichtheimia isolates (except CNM-CM 5399 and FSU 10566) were identified accurately with score values of >2 (probable species identification), and 25 of 34 isolates were identified to the species level with score values of >2.3 (highly probable species identification). The MALDI-TOF MS-based method reported here was found to be reproducible and accurate, with low consumable costs and minimal preparation time. PMID:22135259

Schrödl, Wieland; Heydel, Tilo; Schwartze, Volker U.; Hoffmann, Kerstin; Große-Herrenthey, Anke; Walther, Grit; Alastruey-Izquierdo, Ana; Rodriguez-Tudela, Juan Luis; Olias, Philipp; Jacobsen, Ilse D.; de Hoog, G. Sybren

2012-01-01

335

Ion Trap Mass Spectrometry  

SciTech Connect

This chapter describes research conducted in a few research groups in the 1990s in which RF quadrupole ion trap mass spectrometers were coupled to a powerful atomic ion source, the inductively coupled plasma used in conventional ICP-MS instruments. Major section titles for this chapter are: RF Quadrupole Ion Traps Features of RF Quadrupole Ion Trap Mass Spectrometers Selective Ion Trapping methods Inductively Coupled Plasma Source Ion Trap Mass Spectrometers

Eiden, Greg C.

2005-09-01

336

Misidentification of Aspergillus nomius and Aspergillus tamarii as Aspergillus flavus: Characterization by Internal Transcribed Spacer, ?-Tubulin, and Calmodulin Gene Sequencing, Metabolic Fingerprinting, and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry  

PubMed Central

Aspergillus nomius and Aspergillus tamarii are Aspergillus species that phenotypically resemble Aspergillus flavus. In the last decade, a number of case reports have identified A. nomius and A. tamarii as causes of human infections. In this study, using an internal transcribed spacer, ?-tubulin, and calmodulin gene sequencing, only 8 of 11 clinical isolates reported as A. flavus in our clinical microbiology laboratory by phenotypic methods were identified as A. flavus. The other three isolates were A. nomius (n = 2) or A. tamarii (n = 1). The results corresponded with those of metabolic fingerprinting, in which the A. flavus, A. nomius, and A. tamarii strains were separated into three clusters based on ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC MS) analysis. The first two patients with A. nomius infections had invasive aspergillosis and chronic cavitary and fibrosing pulmonary and pleural aspergillosis, respectively, whereas the third patient had A. tamarii colonization of the airway. Identification of the 11 clinical isolates and three reference strains by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) showed that only six of the nine strains of A. flavus were identified correctly. None of the strains of A. nomius and A. tamarii was correctly identified. ?-Tubulin or the calmodulin gene should be the gene target of choice for identifying A. flavus, A. nomius, and A. tamarii. To improve the usefulness of MALDI-TOF MS, the number of strains for each species in MALDI-TOF MS databases should be expanded to cover intraspecies variability. PMID:24452174

Tam, Emily W. T.; Chen, Jonathan H. K.; Lau, Eunice C. L.; Ngan, Antonio H. Y.; Fung, Kitty S. C.; Lee, Kim-Chung; Lam, Ching-Wan; Yuen, Kwok-Yung

2014-01-01

337

Imaging mass spectrometry in microbiology  

PubMed Central

Mass spectrometry tools which allow for the 2-D visualization of the distribution of trace metals, metabolites, surface lipids, peptides and proteins directly from biological samples without the need for chemical tagging or antibodies are becoming increasingly useful for microbiology applications. These tools, comprised of different imaging mass spectrometry techniques, are ushering in an exciting new era of discovery by allowing for the generation of chemical hypotheses based on of the spatial mapping of atoms and molecules that can correlate to or transcend observed phenotypes. In this review, we explore the wide range of imaging mass spectrometry techniques available to microbiologists and describe their unique applications to microbiology with respect to the types of microbiology samples to be investigated. PMID:21822293

Watrous, Jeramie D.; Dorrestein, Pieter C.

2013-01-01

338

Symposium on accelerator mass spectrometry  

SciTech Connect

The area of accelerator mass spectrometry has expanded considerably over the past few years and established itself as an independent and interdisciplinary research field. Three years have passed since the first meeting was held at Rochester. A Symposium on Accelerator Mass Spectrometry was held at Argonne on May 11-13, 1981. In attendance were 96 scientists of whom 26 were from outside the United States. The present proceedings document the program and excitement of the field. Papers are arranged according to the original program. A few papers not presented at the meeting have been added to complete the information on the status of accelerator mass spectrometry. Individual papers were prepared separately for the data base.

None

1981-01-01

339

Application of Whole-Cell Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Rapid Identification and Clustering Analysis of Pantoea Species ? †  

PubMed Central

Pantoea agglomerans is an ecologically diverse taxon that includes commercially important plant-beneficial strains and opportunistic clinical isolates. Standard biochemical identification methods in diagnostic laboratories were repeatedly shown to run into false-positive identifications of P. agglomerans, a fact which is also reflected by the high number of 16S rRNA gene sequences in public databases that are incorrectly assigned to this species. More reliable methods for rapid identification are required to ascertain the prevalence of this species in clinical samples and to evaluate the biosafety of beneficial isolates. Whole-cell matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) methods and reference spectra (SuperSpectrum) were developed for accurate identification of P. agglomerans and related bacteria and used to detect differences in the protein profile within variants of the same strain, including a ribosomal point mutation conferring streptomycin resistance. MALDI-TOF MS-based clustering was shown to generally agree with classification based on gyrB sequencing, allowing rapid and reliable identification at the species level. PMID:20453125

Rezzonico, Fabio; Vogel, Guido; Duffy, Brion; Tonolla, Mauro

2010-01-01

340

Identification of the corn pathogen Pantoea stewartii by mass spectrometry of whole-cell extracts and its detection with novel PCR primers.  

PubMed

Pantoea stewartii subsp. stewartii is the causative agent of Stewart's wilt, a bacterial disease transmitted by the corn flea beetle mainly to sweet corn (Zea mays). In many countries, it is classified as a quarantine organism and must be differentiated from other yellow enteric bacteria frequently occurring with corn. We have created novel primers from the pstS-glmS region of P. stewartii for use in conventional PCR (cPCR) and quantitative PCR (qPCR). To facilitate rapid diagnosis, we applied matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analysis. Using whole-cell protein extracts, profiles were generated with a Bruker microflex machine, and the bacteria classified. P. stewartii strains were clearly distinguished from strains of Pantoea agglomerans, Pantoea dispersa, and Pantoea ananatis. Dendrogram analysis of the protein profiles confirmed the score values and showed the formation of separate clades for each species. The identification achieved by MALDI-TOF MS analysis agrees with the diagnosis by specific PCR primers. The combination of both methods allows a rapid and simple identification of the corn pathogen. P. stewartii subsp. stewartii and P. stewartii subsp. indologenes are highly related and can be distinguished not only by virulence assays and indole tests but also by a characteristic pattern in the nucleotide sequence of recA. PMID:20656863

Wensing, Annette; Zimmermann, Stefan; Geider, Klaus

2010-09-01

341

Utilization of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for structural studies related to biology and disease  

NASA Astrophysics Data System (ADS)

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), because of its high sensitivity and relatively straightforward requirements for sample preparation, is contributing to the solution of structural problems in biology and to the development of therapeutic approaches through increased understanding of pharmacology and enhanced capabilities for quality control of pharmaceuticals. We are using a reflectron TOF- MS for the determination of molecular weights of individual compounds and the components of mixtures that are naturally occurring or are generated through enzymic digests, and employing the post-source decay mode to elucidate structural details. To maximize the sensitivity and information content of the spectra, varied matrices, derivative, and stepwise degradation procedures are being explored. Present studies include investigations of oligosaccharides, neutral glycolipids, gangliosides, glycoproteins, neuropeptides and proteins. Rules for fragmentation are being developed with model compounds and used for the structural elucidation of unknowns. When adequate sample amounts are available, the results are compared with low- and high-energy collision-induced decomposition spectra obtained with tandem MS in order to provide a data base for the correlation of spectral features and guidance in selection of approaches for scarce biological samples. Current projects include biophysical studies of glycoplipids, glycoproteins and oligosaccharides and investigations of the substance P receptor, transthyretin genetic variants and cisplatin-DNA interactions.

Costello, Catherine E.; Helin, Jari; Ngoka, Lambert C. M.

1996-04-01

342

Identification of estrogen receptor proteins in breast cancer cells using matrix-assisted laser desorption/ionization time of flight mass spectrometry (Review)  

PubMed Central

Estrogen receptors [ERs (subtypes ? and ?)], classified as a nuclear receptor super family, are intracellular proteins with an important biological role as the transcription factors for estrogen target genes. For ER-induced transcription, an interaction must exist between ligand and coregulators. Coregulators may stimulate (coactivators) or inhibit (corepressors) transcription, following binding with a specific region of the gene, called the estrogen response element. Misbalanced activity of coregulators or higher ligand concentrations may cause increased cell proliferation, resulting in specific types of cancer. These are exhibited as overexpression of ER proteins. Breast cancer currently ranks first in the incidence and second in the mortality of cancer in females worldwide. In addition, 70% of breast tumors are ER? positive and the importance of these proteins for diagnostic use is indisputable. Early diagnosis of the tumor and its classification has a large influence on the selection of appropriate therapy, as ER-positive tumors demonstrate a positive response to hormonal therapy. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI TOF MS) has been hypothesized to have great potential, as it offers reliable, robust and efficient analysis methods for biomarker monitoring and identification. The present review discusses ER protein analysis by MALDI TOF MS, including the crucial step of protein separation. PMID:24765135

HEGER, ZBYNEK; RODRIGO, MIGUEL ANGEL MERLOS; KRIZKOVA, SONA; ZITKA, ONDREJ; BEKLOVA, MIROSLAVA; KIZEK, RENE; ADAM, VOJTECH

2014-01-01

343

Probing chain-end functionalization reactions in living anionic polymerization via matrix-assisted laser desorption ionization time-of-flight mass spectrometry  

NASA Astrophysics Data System (ADS)

Matrix-assisted laser desorption ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) is applied to examine the products arising upon the preparation of chain-end functional polymers via living anionic polymerization techniques. Both post-polymerization functionalizations as well as the use of functionalized initiators are investigated. MALDI-TOF MS is shown to be a sensitive probe for the qualitative analysis of the major and minor oligomers from novel functionalization reactions whose mechanisms are not yet well established. The method is particularly valuable for the identification of the end groups of the minor, and often unexpected, distributions that may be undetectable by other analytical means. Complete characterization of all oligomers generated during functionalization reactions provides an essential tool to the synthetic chemist for understanding the corresponding mechanisms. This insight is necessary for selecting alternative routes or making modifications to the reaction conditions. It is demonstrated that MALDI-TOF MS can convey quantitative information about the yields of the chain-end groups introduced during functionalization. From the cases presented it is evident that post-polymerization reactions allow for better control of chain-end functionality and molecular weight than functionalization with the limited number of currently available protected functionalized initiators.

Arnould, Mark A.; Polce, Michael J.; Quirk, Roderic P.; Wesdemiotis, Chrys

2004-11-01

344

MALDI-TOF Mass Spectrometry Is a Fast and Reliable Platform for Identification and Ecological Studies of Species from Family Rhizobiaceae  

PubMed Central

Family Rhizobiaceae includes fast growing bacteria currently arranged into three genera, Rhizobium, Ensifer and Shinella, that contain pathogenic, symbiotic and saprophytic species. The identification of these species is not possible on the basis of physiological or biochemical traits and should be based on sequencing of several genes. Therefore alternative methods are necessary for rapid and reliable identification of members from family Rhizobiaceae. In this work we evaluated the suitability of Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) for this purpose. Firstly, we evaluated the capability of this methodology to differentiate among species of family Rhizobiaceae including those closely related and then we extended the database of MALDI Biotyper 2.0 including the type strains of 56 species from genera Rhizobium, Ensifer and Shinella. Secondly, we evaluated the identification potential of this methodology by using several strains isolated from different sources previously identified on the basis of their rrs, recA and atpD gene sequences. The 100% of these strains were correctly identified showing that MALDI-TOF MS is an excellent tool for identification of fast growing rhizobia applicable to large populations of isolates in ecological and taxonomic studies. PMID:21655291

Ferreira, Laura; Sanchez-Juanes, Fernando; Garcia-Fraile, Paula; Rivas, Raul; Mateos, Pedro F.; Martinez-Molina, Eustoquio; Gonzalez-Buitrago, Jose Manuel; Velazquez, Encarna

2011-01-01

345

Analysis of noncovalent chitinase-chito-oligosaccharide complexes by infrared-matrix assisted laser desorption ionization and nanoelectrospray ionization mass spectrometry.  

PubMed

Transferring noncovalently bound complexes from the condensed phase into the gas phase represents a challenging task due to weak intermolecular bonds that have to be maintained during the phase transition. Currently, electrospray ionization (ESI) is the standard mass spectrometric (MS) technique to analyze noncovalent complexes. Although infrared matrix-assisted laser desorption ionization (IR-MALDI)-MS also provides particular soft desorption/ionization conditions, this method has so far hardly been applied for the analysis of noncovalent complexes. In this study, we employed IR-MALDI orthogonal time-of-flight (o-TOF)-MS in combination with the liquid matrix glycerol to characterize the specific complex formation of chito-oligosaccharide (CHOS) ligands with two variants of Chitinase A (ChiA) from Serratia marcescens, the inactive E315Q mutant and the active W167A mutant, respectively. The IR-MALDI-o-TOF-MS results were compared to those obtained using nano-ESI-quadrupole (q)-TOF-MS and ultraviolet (UV)-MALDI-o-TOF-MS. Using IR-MALDI-o-TOF-MS, specific noncovalent complexes between ChiA and CHOS were detected with distributions between enzymes with bound oligosaccharides vs free enzymes that were essentially identical to those obtained by nano-ESI-q-TOF-MS. Chitinase-CHOS complexes were not detected when UV-MALDI was employed for desorption/ionization. The results show that IR-MALDI-MS can be a valuable tool for fast and simple screening of noncovalent enzyme-ligand interactions. PMID:21473578

Dybvik, Anette I; Norberg, Anne Line; Schute, Veronika; Soltwisch, Jens; Peter-Katalini?, Jasna; Vårum, Kjell M; Eijsink, Vincent G H; Dreisewerd, Klaus; Mormann, Michael; Sørlie, Morten

2011-06-01

346

Rapid characterization of triterpene saponins from Conyza blinii by liquid chromatography coupled with mass spectrometry.  

PubMed

Conyza blinii Le'vl is a medicinal herb used for the treatment of inflammation in Chinese folk medicine. Its major bioactive constituents are triterpene saponins, most of which contain 6-8 sugar residues. In this report, electrospray ionization tandem mass spectrometry fragmentation behaviors of bisdesmosidic triterpene saponins (conyzasaponin A, B, and C) were studied in both positive and negative ion modes with an ion-trap mass spectrometer. In full scan mass spectrometry, these saponins gave predominant [M-H](-) and [M+Na](+) ions, which determined the molecular weights. In tandem mass spectrometry (MS(n), n?=?2-4), the [M-H](-) and [M+Na](+) ions yielded fragments [Y(0?)-H](-) and [B(?)+Na](+), which were diagnostic for the structures of the triterpene skeleton and sugar chains. The structural elucidation was approved by accurate mass data using IT-TOF-MS. An interpretation guideline based on MS(n) (n?=?2-4) diagnostic ions was proposed in order to elucidate the chemical structures of unknown triterpene saponins in C. blinii extract. The saponins in C. blinii were separated by liquid chromatography with a methanol/acetonitrile/water solvent system, and then analyzed by ion-trap and IT-TOF mass spectrometers. Based on the interpretation guideline, a total of 35 triterpenoid saponins were tentatively identified. Among them, 15 saponins had been previously reported, and the other 20 saponins were reported from Conyza species for the first time. This study indicates that LC/MS is a powerful technology for the rapid characterization of complicated saponins in herbal extracts. PMID:20973010

Qiao, Xue; Zhang, Xing; Ye, Min; Su, Yan-fang; Dong, Jing; Han, Jian; Yin, Jun; Guo, De-an

2010-11-30

347

Intact Cell/Spore Mass Spectrometry of Fusarium Macro Conidia for Fast Isolate and Species Differentiation  

NASA Astrophysics Data System (ADS)

The focus of this paper is the development of an approach called intact cell mass spectrometry (ICMS) or intact spore mass spectrometry (ISMS) based on the technique matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) for the rapid differentiation and identification of Fusarium species. Several parameters, which are known to affect the quality of IC mass spectra, have been investigated in detail by varying the MALDI matrix as well as the solvent system, in which the matrix has been dissolved, the solvent system for sample purification and the type of sample/MALDI matrix deposition technique. In the end characteristic as well as highly reproducible IC or IS mass spectra or peptide/protein fingerprints of three Fusarium species (F. cerealis, F. graminearum and F. poae) including 16 Fusarium isolates derived from different hosts and geographical locations have been obtained. Unscaled hierarchical cluster analysis based on ICMS data of eight selected Fusarium isolates of two species F. graminearum and F. poae revealed significant difference among the peptide/protein pattern of them. The results of the applied cluster analysis proved that, ICMS is a powerful approach for the rapid differentiation of Fusarium species. In addition, an on-target tryptic digestion was applied to Fusarium macro conidia spores to identify proteins using MALDI post source decay (PSD) fragment ion analysis. Two kinds of trypsin, namely bead-immobilized - to favor cleavage of surface-associated proteins - and non-immobilized trypsin were applied and compared. The results showed that the latter is more suitable for generating sequence tags by PSD fragment ion analysis.

Dong, Hongjuan; Marchetti-Deschmann, Martina; Winkler, Wolfgang; Lohninger, Hans; Allmaier, Guenter

348

Algorithms for Peptide Mass Spectrometry  

E-print Network

Algorithms for Peptide Mass Spectrometry Ole Schulz-Trieglaff Max Planck Research School;Why bother ? · Clinical studies but also basic research rely on an accurate quantification of peptides. Stability analysis: can we detect distorted isotopic pattern, too ? Add uniformly distributed noise

Spang, Rainer

349

Open Mass Spectrometry Search Algorithm  

Microsoft Academic Search

Large numbers of MS\\/MS peptide spectra generated in proteomics experiments require efficient, sensitive and specific algorithms for peptide identification. In the Open Mass Spectrometry Search Algorithm [OMSSA], specificity is calculated by a classic probability score using an explicit model for matching experimental spectra to sequences. At default thresholds, OMSSA matches more spectra from a standard protein cocktail than a comparable

Lewis Y. Geer; Sanford P. Markey; Jeffrey A. Kowalak; Lukas Wagner; Ming Xu; Dawn M. Maynard; Xiaoyu Yang; Wenyao Shi; Stephen H. Bryant

2004-01-01

350

Tandem Mass Spectrometry in Physiology  

NSDL National Science Digital Library

Tandem mass spectrometry coupled to liquid chromatography (LC-MS/MS) allows identification of proteins in a complex mixture without need for protein purification ("shotgun" proteomics). Recent progress in LC-MS/MS-based quantification, phosphoproteomic analysis, and targeted LC-MS/MS using multiple reaction monitoring (MRM) has made LC-MS/MS a powerful tool for the study of cell physiology.

2007-12-01

351

A Rocket-Borne Axially Sampling Time-of-Flight Mass Spectrometer for Investigation of the Upper Atmosphere  

NASA Astrophysics Data System (ADS)

We have previously reported results from modeling and simulation efforts and preliminary laboratory testing for a new rocket-borne time-of-flight mass spectrometer (TOF-MS) for direct, in-situ measurements in the mesosphere/lower thermosphere (MLT) region of Earth's atmosphere. Mass spectrometry in the MLT is difficult, mainly due to the high ambient pressures in the MLT and also the high speeds and short flight durations of sounding rocket missions. In particular, TOF-MS has rarely been applied to the MLT, owing to the dependence of this MS technique on high acceleration voltages and microchannel plate (MCP) detectors. To overcome these obstacles, the TOF-MS relies on a pressure tolerant MCP as well as modest acceleration potentials (100 V - 300 V). The TOF-MS is adaptable and vacuum requirements can be met by several options, including an innovative design using an inexpensive barium getter tube system, mechanical pumping system, or a cryogenic pumping system. This presentation highlights results from laboratory testing of a prototype TOF-MS instrument, demonstrating the ability of the TOF-MS to survive and operate in the challenging MLT region. MCP's have traditionally required vacuum conditions of 10-6 torr or better for operation. We have rigorously tested the effects of pressure on the MCP detector used in the TOF-MS under backfills of gases including He, Ar, N2, and lab air, at pressures extending into the 10-2 torr range. We have also tested the effect of humidity on MCP performance. Discharge events were also tracked. These experiments demonstrate the ability of the MCP detector to perform under the high pressure conditions likely to be encountered on a sounding rocket in the MLT. Additionally, optimal operating parameters for the laboratory prototype TOF-MS have been experimentally determined and applied to study the effects of pressure on the resolution and SNR of mass spectra taken with the TOF-MS. The TOF-MS has successfully operated with internal pressures as high as 2×10-4 torr while maintaining unit mass resolution at 40 u (Ar+). Experimental data on the pumping capabilities of the innovative getter-based vacuum pumping system for the TOF-MS is also presented. This system involves the use of inexpensive single-use barium loaded getter tubes to provide vacuum pumping on a sounding rocket flight. Attractive features of this pumping system include the low cost of getter tubes in comparison with mechanical or cryogenic pumping systems, as well as the total lack of moving parts associated with mechanical pumping systems. The experimentally derived getter tube pumping data is integrated into a computer model to simulate the instrument pressure on a typical sounding rocket flight to the MLT and compared to simulated instrument pressure profiles for other possible vacuum pumping options. A specific example of one potential area of interest is making measurements to investigate the transition of the atmosphere from turbulently mixed to diffusive equilibrium by looking at the mixing ratios of atmospheric gas species. The TOF-MS will enable measurements of major atmospheric species in the MLT, which will advance our understanding of composition and dynamics in the transition region.

Everett, E. A.; Syrstad, E. A.

2013-12-01

352

Detection of drugs in lifted cyanoacrylate-developed latent fingermarks using two laser desorption/ionisation mass spectrometric methods.  

PubMed

This paper describes a method for lifting cyanoacrylate (CNA)-developed latent fingermarks from a glass surface and the detection of five drugs in lifted marks from fingers that had been in contact with the drugs, using Surface Assisted Laser Desorption Ionisation Time of Flight Mass Spectrometry (SALDI-TOF-MS) or Matrix Assisted Laser Desorption Ionisation TOF-MS (MALDI-TOF-MS). Two drugs of abuse (cocaine and methadone) and three therapeutic drugs (aspirin, paracetamol and caffeine) were used as contact residues. Latent fingermarks spiked with the drugs were subjected to CNA fuming followed by dusting with ARRO SupraNano™ MS black magnetic powder (SALDI-TOF-MS) or 2,5-dihydroxybenzoic acid (DHB) (MALDI-TOF-MS). The dusted mark was then exposed to solvent vapour before lifting with a commercial fingerprint lifting tape following established procedures. The presence of the drugs was then confirmed by direct analysis on the tape without further processing using SALDI- or MALDI-TOF-MS. The black magnetic fingerprint powder provided visual enhancement of the CNA-fingermark while no visual enhancement was observed for marks dusted with DHB powder. Similar [M + H](+) peaks for all the drug analytes were observed for both methods along with some sodium and potassium adducts for SALDI-MS and some major fragment ions but the SALDI signals were generally more intense. Simple exposure to acetone vapour of the CNA-developed marks enabled their effective transfer onto the tape which was crucial for subsequent MS detection of the analytes. PMID:24319772

Sundar, Latha; Rowell, Frederick

2014-02-01

353

MASS SPECTROMETRY-BASED METABOLOMICS  

PubMed Central

This review presents an overview of the dynamically developing field of mass spectrometry-based metabolomics. Metabolomics aims at the comprehensive and quantitative analysis of wide arrays of metabolites in biological samples. These numerous analytes have very diverse physico-chemical properties and occur at different abundance levels. Consequently, comprehensive metabolomics investigations are primarily a challenge for analytical chemistry and specifically mass spectrometry has vast potential as a tool for this type of investigation. Metabolomics require special approaches for sample preparation, separation, and mass spectrometric analysis. Current examples of those approaches are described in this review. It primarily focuses on metabolic fingerprinting, a technique that analyzes all detectable analytes in a given sample with subsequent classification of samples and identification of differentially expressed metabolites, which define the sample classes. To perform this complex task, data analysis tools, metabolite libraries, and databases are required. Therefore, recent advances in metabolomics bioinformatics are also discussed. PMID:16921475

Dettmer, Katja; Aronov, Pavel A.; Hammock, Bruce D.

2007-01-01

354

Accelerator mass spectrometry  

SciTech Connect

Accelerator mass spectroscopy (AMS) can be used for efficient detection of long-lived isotopes at part-per-quadrillion sensitivities with good precision. In this article we present an overview of AMS and its recent use in archaeology, geochemistry and biomolecular tracing. All AMS systems use cesium sputter ion sources to produce negative ions from a small button of a solid sample containing the element of interest, such as graphite, metal halide, or metal oxide, often mixed with a metal powder as binder and thermal conductor. Experience shows that both natural and biomedical samples are compatible in a single AMS system, but few other AMS sites make routine {sup 14}C measurements for both dating and tracing. AMS is, in one sense, just `a very sensitive decay counter`, but if AMS sensitivity is creatively coupled to analytical chemistry of certain isotopes, whole new areas of geosciences, archaeology, and life sciences can be explored. 29 refs., 2 figs., 1 tab.

Vogel, J.S.; Turteltaub, K.W.; Finkel, R. [Lawrence Livermore National Lab., CA (United States); Nelson, D.E.

1995-06-01

355

THERMOSPRAY MASS SPECTROMETRY AND THERMOSPRAY MASS SPECTROMETRY/MASS SPECTROMETRY OF TWO DEOXYGUANOSINE CARCINOGEN ADDUCTS  

EPA Science Inventory

Analysis of N-(deoxyguanosin-8-yl)-2-acetylaminofluorene (dG-C8-AAF) and N-(deoxyguanosin-8-yl)-2-aminofluorene (dG-C8-AF) by thermospray mass spectrometry (TSP/MS) provided (MH)+ ions. TSP/MS/MS of the (MH)+ ions produced (BH2)+ ions....

356

A PROTEOMIC (SELDI-TOF-MS) APPROACH TO ESTROGEN AGONIST SCREENING  

EPA Science Inventory

A small fish model and surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI) were used to investigate plasma protein expression as a means to screen chemicals for estrogenic activity. Adult male sheepshead minnows (Cyprinodon variegatus) were place...

357

LIMPIC: a computational method for the separation of protein MALDI-TOF-MS signals from noise  

Microsoft Academic Search

BACKGROUND: Mass spectrometry protein profiling is a promising tool for biomarker discovery in clinical proteomics. However, the development of a reliable approach for the separation of protein signals from noise is required. In this paper, LIMPIC, a computational method for the detection of protein peaks from linear-mode MALDI-TOF data is proposed. LIMPIC is based on novel techniques for background noise

Dante Mantini; Francesca Petrucci; Damiana Pieragostino; Piero Del Boccio; Marta Di Nicola; Carmine Di Ilio; Giorgio Federici; Paolo Sacchetta; Silvia Comani; Andrea Urbani

2007-01-01

358

Development of GCxGC\\/TOF-MS metabolomics for use in ecotoxicological studies with invertebrates  

Microsoft Academic Search

The majority of metabolomic studies used in ecotoxicology have implemented 1H NMR analysis. Despite constant improvement, major limitations of NMR-based techniques include relatively low sensitivity that results in an examination of a limited number of metabolites. An alternative approach is the use of liquid or gas chromatography (GC) for separation of metabolites and mass spectrometry (MS) for their quantification and

Kimberly Ralston-Hooper; Amber Hopf; Cheolhwan Oh; Xiang Zhang; Jiri Adamec; Maria S. Sepúlveda

2008-01-01

359

Rapid Antifungal Susceptibility Testing by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Analysis  

PubMed Central

The widespread use of antifungal agents, which is likely to expand with their enhanced availability, has promoted the emergence of drug-resistant strains. Antifungal susceptibility testing (AFST) is now an essential procedure for guiding appropriate antifungal therapy. Recently, we developed a matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS)-based method that enables the detection of fungal isolates with reduced echinocandin susceptibility, relying on the proteome changes that are detectable after a 15-h exposure of fungal cells to serial drug concentrations. Here, we describe a simplified version of this approach that facilitates discrimination of the susceptible and resistant isolates of Candida albicans after a 3-h incubation in the presence of “breakpoint” level drug concentrations of the echinocandin caspofungin (CSF). Spectra at concentrations of 0 (null), 0.03 (intermediate), and 32 (maximal) ?g/ml of CSF were used to create individual composite correlation index (CCI) matrices for 65 C. albicans isolates, including 13 fks1 mutants. Isolates are then classified as susceptible or resistant to CSF if the CCI values of spectra at 0.03 and 32 ?g/ml are higher or lower, respectively, than the CCI values of spectra at 0.03 and 0 ?g/ml. In this way, the drug resistance of C. albicans isolates to echinocandin antifungals can be quickly assessed. Furthermore, the isolate categorizations determined using MALDI-TOF MS-based AFST (ms-AFST) were consistent with the wild-type and mutant FKS1 genotypes and the AFST reference methodology. The ms-AFST approach may provide a rapid and reliable means of detecting emerging antifungal resistance and accelerating the initiation of appropriate antifungal treatment. PMID:23824764

Vella, Antonietta; De Carolis, Elena; Vaccaro, Luisa; Posteraro, Patrizia; Perlin, David S.; Kostrzewa, Markus

2013-01-01

360

Ion Funnel Trap Interface for Orthogonal Time-of-Flight Mass Spectrometry  

SciTech Connect

A combined electrodynamic ion funnel and ion trap coupled to an orthogonal acceleration (oa)-time-of-flight mass spectrometer was developed and characterized. The ion trap was incorporated through the use of added terminal electrodynamic ion funnel electrodes enabling control over the axial dc gradient in the trap section. The ion trap operates efficiently at a pressure of ~1 Torr, and measurements indicate a maximum charge capacity of ~3 × 107 charges. An order of magnitude increase in sensitivity was observed in the analysis of low concentration peptides mixtures with orthogonal acceleration (oa)-time-of-flight mass spectrometry (oa-TOF MS) in the trapping mode as compared to the continuous regime. A signal increase in the trapping mode was accompanied by reduction in the chemical background, due to more efficient desolvation of, for example, solvent related clusters. Controlling the ion trap ejection time was found to result in efficient removal of singly charged species and improving signal-to-noise ratio (S/N) for the multiply charged analytes.

Ibrahim, Yehia M.; Belov, Mikhail E.; Tolmachev, Aleksey V.; Prior, David C.; Smith, Richard D.

2007-10-15

361

Ion funnel trap interface for orthogonal time-of-flight mass spectrometry.  

PubMed

A combined electrodynamic ion funnel and ion trap coupled to an orthogonal acceleration (oa)-time-of-flight mass spectrometer was developed and characterized. The ion trap was incorporated through the use of added terminal electrodynamic ion funnel electrodes enabling control over the axial dc gradient in the trap section. The ion trap operates efficiently at a pressure of approximately 1 Torr, and measurements indicate a maximum charge capacity of approximately 3 x 10(7) charges. An order of magnitude increase in sensitivity was observed in the analysis of low concentration peptides mixtures with orthogonal acceleration (oa)-time-of-flight mass spectrometry (oa-TOF MS) in the trapping mode as compared to the continuous regime. A signal increase in the trapping mode was accompanied by reduction in the chemical background, due to more efficient desolvation of, for example, solvent related clusters. Controlling the ion trap ejection time was found to result in efficient removal of singly charged species and improving signal-to-noise ratio (S/N) for the multiply charged analytes. PMID:17850113

Ibrahim, Yehia; Belov, Mikhail E; Tolmachev, Aleksey V; Prior, David C; Smith, Richard D

2007-10-15

362

Mass spectrometry and renal calculi  

PubMed Central

The present review represents a concise and complete survey of the literature covering 2004–2009, concerning the mass spectrometric techniques involved in the structural investigation of renal calculi. After a short presentation of the fundamental mass spectrometric techniques (MALDI–TOF, QTOF, MS–MS) as well as hyphenated methods (GC–MS, LC–MS, CE–MS), an extensive study of the urinary proteome analysis as well as the detection and quantification by mass spectrometry of toxins, drugs and metabolites from renal calculi is presented. PMID:20968197

Purcarea, VL; Sisu, I; Sisu, E

2010-01-01

363

Mass spectrometry of aerospace materials  

NASA Technical Reports Server (NTRS)

Mass spectrometry is used for chemical analysis of aerospace materials and contaminants. Years of analytical aerospace experience have resulted in the development of specialized techniques of sampling and analysis which are required in order to optimize results. This work has resulted in the evolution of a hybrid method of indexing mass spectra which include both the largest peaks and the structurally significant peaks in a concise format. With this system, a library of mass spectra of aerospace materials was assembled, including the materials responsible for 80 to 90 percent of the contamination problems at Goddard Space Flight Center during the past several years.

Colony, J. A.

1976-01-01

364

Characterization of the organic contamination pattern of a hyper-saline ecosystem by rapid screening using gas chromatography coupled to high-resolution time-of-flight mass spectrometry.  

PubMed

In this paper, gas chromatography coupled to high-resolution time-of-flight mass spectrometry (GC-TOF MS) has been applied to evaluate organic pollution in a hyper-saline aquatic environment. Firstly, a target screening was made for a list of 150 GC-amenable organic micro-contaminants, including PAHs, octyl/nonyl phenols, PCBs, PBDEs, and a notable number of pesticides, such us insecticides (organochlorines, organophosphorus, carbamates and pyrethroids), herbicides (triazines and chloroacetanilides), fungicides and several transformation products. This methodology was applied to brine samples, with a salt content from 112 g/L to saturation, and to samples from Artemia populations (crustacean Anostraca) collected during 1 year from three sampling stations in saltworks bodies sited in the Ebro river delta. Around 50 target contaminants, belong to chemical families included in the list of priority substances within the framework on European water policy. Additionally, a non-target analysis was performed in both types of samples with the objective of investigating the presence of other non-selected organic compounds taking advantage of the potential of GC-TOF MS (high sensitivity in full-spectrum acquisition mode, accurate mass measurements) for searching unknowns. Organophosphorus pesticides were the contaminants more frequently detected in brine samples. Other compounds usually present in urban and industrial wastewaters, like caffeine, methylparaben, butylated-hydroxytoluene and N-butylbenzenesulfonamide were also detected in brines. The herbicide simazine and the insecticide chlorpyrifos were among the contaminants detected in Artemia samples. Results of this work reveal a potential threat to vulnerable populations inhabiting the hyper-saline ecosystem. The valuable contribution of GC-TOF MS in environmental analysis, allowing the rapid screening of a large number of organic contaminants, is also demonstrated in this paper. PMID:22789816

Serrano, Roque; Portolés, Tania; Blanes, Miguel A; Hernández, Félix; Navarro, Juan C; Varó, Inmaculada; Amat, Francisco

2012-09-01

365

Differentiation in MALDI-TOF MS and FTIR spectra between two closely related species Acidovorax oryzae and Acidovorax citrulli  

PubMed Central

Background Two important plant pathogenic bacteria Acidovorax oryzae and Acidovorax citrulli are closely related and often not easy to be differentiated from each other, which often resulted in a false identification between them based on traditional methods such as carbon source utilization profile, fatty acid methyl esters, and ELISA detection tests. MALDI-TOF MS and Fourier transform infrared (FTIR) spectra have recently been successfully applied in bacterial identification and classification, which provide an alternate method for differentiating the two species. Results Characterization and comparison of the 10 A. oryzae strains and 10 A. citrulli strains were performed based on traditional bacteriological methods, MALDI-TOF MS, and FTIR spectroscopy. Our results showed that the identity of the two closely related plant pathogenic bacteria A. oryzae and A. citrulli was able to be confirmed by both pathogenicity tests and species-specific PCR, but the two species were difficult to be differentiated based on Biolog and FAME profile as well as 16?S rRNA sequence analysis. However, there were significant differences in MALDI-TOF MS and FTIR spectra between the two species of Acidovorax. MALDI-TOF MS revealed that 22 and 18 peaks were specific to A. oryzae and A. citrulli, respectively, while FTIR spectra of the two species of Acidovorax have the specific peaks at 1738, 1311, 1128, 1078, 989?cm-1 and at 1337, 968, 933, 916, 786?cm-1, respectively. Conclusions This study indicated that MALDI-TOF MS and FTIR spectra may give a new strategy for rapid bacterial identification and differentiation of the two closely related species of Acidovorax. PMID:22900823

2012-01-01

366

Mass Spectrometry and Computational Proteomics Vineet Bafna  

E-print Network

Mass Spectrometry and Computational Proteomics Vineet Bafna Computer Science & Engineering, Univ Abstract Mass Spectrometry is the tool of choice for Proteomics, with applications to peptide sequencing of algorithms for interpreting mass spectrometry (MS) data is provided. This overview is not intended

Bafna, Vineet

367

Application of Mass Spectrometry in Proteomics  

Microsoft Academic Search

Mass spectrometry has arguably become the core technology in proteomics. The application of mass spectrometry based techniques for the qualitative and quantitative analysis of global proteome samples derived from complex mixtures has had a big impact in the understanding of cellular function. Here, we give a brief introduction to principles of mass spectrometry and instrumentation currently used in proteomics experiments.

Ida Chiara Guerrera; Oliver Kleiner

2005-01-01

368

Multidimensional gas chromatography in combination with accurate mass, tandem mass spectrometry, and element-specific detection for identification of sulfur compounds in tobacco smoke.  

PubMed

A method is developed for identification of sulfur compounds in tobacco smoke extract. The method is based on large volume injection (LVI) of 10?L of tobacco smoke extract followed by selectable one-dimensional ((1)D) or two-dimensional ((2)D) gas chromatography (GC) coupled to a hybrid quadrupole time-of-flight mass spectrometer (Q-TOF-MS) using electron ionization (EI) and positive chemical ionization (PCI), with parallel sulfur chemiluminescence detection (SCD). In order to identify each individual sulfur compound, sequential heart-cuts of 28 sulfur fractions from (1)D GC to (2)D GC were performed with the three MS detection modes (SCD/EI-TOF-MS, SCD/PCI-TOF-MS, and SCD/PCI-Q-TOF-MS). Thirty sulfur compounds were positively identified by MS library search, linear retention indices (LRI), molecular mass determination using PCI accurate mass spectra, formula calculation using EI and PCI accurate mass spectra, and structure elucidation using collision activated dissociation (CAD) of the protonated molecule. Additionally, 11 molecular formulas were obtained for unknown sulfur compounds. The determined values of the identified and unknown sulfur compounds were in the range of 10-740ngmg total particulate matter (TPM) (RSD: 1.2-12%, n=3). PMID:25087743

Ochiai, Nobuo; Mitsui, Kazuhisa; Sasamoto, Kikuo; Yoshimura, Yuta; David, Frank; Sandra, Pat

2014-09-01

369

Rapid Identification of Viridans Streptococci by Mass Spectrometric Discrimination  

Microsoft Academic Search

Viridans streptococci (VS) are responsible for several systemic diseases, such as endocarditis, abscesses, and septicemia. Unfortunately, species identification by conventional methods seems to be more difficult than species identification of other groups of bacteria. The aim of the present study was to evaluate the use of cell matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) for the rapid identification

C. Friedrichs; A. C. Rodloff; G. S. Chhatwal; W. Schellenberger; K. Eschrich

2007-01-01

370

Suspect screening and target quantification of multi-class pharmaceuticals in surface water based on large-volume injection liquid chromatography and time-of-flight mass spectrometry.  

PubMed

The ever-growing number of emerging micropollutants such as pharmaceuticals requests rapid and sensitive full-spectrum analytical techniques. Time-of-flight high-resolution mass spectrometry (TOF-HRMS) is a promising alternative for the state-of-the-art tandem mass spectrometry instruments because of its ability to simultaneously screen for a virtually unlimited number of suspect analytes and to perform target quantification. The challenge for such suspect screening is to develop a strategy, which minimizes the false-negative rate without restraining numerous false-positives. At the same time, omitting laborious sample enrichment through large-volume injection ultra-performance liquid chromatography (LVI-UPLC) avoids selective preconcentration. A suspect screening strategy was developed using LVI-UPLC-TOF-MS aiming the detection of 69 multi-class pharmaceuticals in surface water without the a priori availability of analytical standards. As a novel approach, the screening takes into account the signal-intensity-dependent accurate mass error of TOF-MS, hereby restraining 95 % of the measured suspect pharmaceuticals present in surface water. Application on five Belgian river water samples showed the potential of the suspect screening approach, as exemplified by a false-positive rate not higher than 15 % and given that 30 out of 37 restrained suspect compounds were confirmed by the retention time of analytical standards. Subsequently, this paper discusses the validation and applicability of the LVI-UPLC full-spectrum HRMS method for target quantification of the 69 pharmaceuticals in surface water. Analysis of five Belgian river water samples revealed the occurrence of 17 pharmaceuticals in a concentration range of 17 ng L(-1) up to 3.1 ?g L(-1). PMID:24633561

Vergeynst, Leendert; Van Langenhove, Herman; Joos, Pieter; Demeestere, Kristof

2014-04-01

371

Mass spectrometry. [review of techniques  

NASA Technical Reports Server (NTRS)

Advances in mass spectrometry (MS) and its applications over the past decade are reviewed in depth, with annotated literature references. New instrumentation and techniques surveyed include: modulated-beam MS, chromatographic MS on-line computer techniques, digital computer-compatible quadrupole MS, selected ion monitoring (mass fragmentography), and computer-aided management of MS data and interpretation. Areas of application surveyed include: organic MS and electron impact MS, field ionization kinetics, appearance potentials, translational energy release, studies of metastable species, photoionization, calculations of molecular orbitals, chemical kinetics, field desorption MS, high pressure MS, ion cyclotron resonance, biochemistry, medical/clinical chemistry, pharmacology, and environmental chemistry and pollution studies.

Burlingame, A. L.; Kimble, B. J.; Derrick, P. J.

1976-01-01

372

Coupling ultra high-pressure liquid chromatography with mass spectrometry: constraints and possible applications.  

PubMed

The introduction of columns packed with porous sub-2?m particles and the extension of the upper pressure limit of HPLC instrumentation to 1300bar (ultra-high pressure liquid chromatography, UHPLC) has opened new frontiers in resolution and speed of analysis. However, certain constraints appear when coupling UHPLC technology with mass spectrometry (MS). First, the most significant limitation is related to the narrow peaks that are produced by UHPLC that require a fast duty cycle, which is only available on the latest generations of MS devices. Thus, certain analyzers are more readily compatible with UHPLC (e.g., QqQ or TOF/MS) than others (e.g., ion trap or FT-MS). Second, due to the reduction of the column volume, extra-column band broadening can become significant, leading to a reduction in the kinetic performance of the UHPLC-MS configuration. Third, as the mobile phase linear velocity is higher in UHPLC, the electrospray ionization source must also be able to provide high sensitivity at flow rates of up to 1mL/min. Despite these limitations, the UHPLC-MS/MS platform has successfully been employed over the last decade for various types of applications, including those related to bioanalysis, drug metabolism, multi-residue screening, metabolomics, biopharmaceuticals and polar compounds. PMID:23062879

Rodriguez-Aller, Marta; Gurny, Robert; Veuthey, Jean-Luc; Guillarme, Davy

2013-05-31

373

Purification and mass spectrometry based characterization of a pediocin produced by Pediococcus acidilactici 13.  

PubMed

Bacteriocins are antimicrobial peptides produced by several bacterial species. Among the bacteriocins pediocin-like bacteriocins have a significant inhibitory activity on the foodborne pathogens especially on Listeria monocytogenes. This study aims to select a simple and usable purification method to purify/concentrate the antimicrobial peptide and characterization of the bacteriocin produced by Pediococcus acidilactici 13 by using proteomic approaches which is a recent omic technology. For purification dialysis, ultrafiltration method was used, and as a result of this study the bacteriocin activity reached 819,200 AU/mL from 102,400 AU/mL initially. Two dimensional gel electrophoresis and then matrix-assisted laser desorption ionization/time of flight mass spectrometry (MALDI-TOF MS) analysis were carried out to identify the current bacteriocin and related proteins. Obtained data revealed similarity to pediocin PA-1 transport/processing ATP-binding protein PedD (accession number: P36497), pediocin operon PedC (accession number: Q68GC4) and bacteriocin pediocin PA-1 (accession number: P29430) from UniProtKB/Swiss-Prot databank, thus the bacteriocin produced by P. acidilactici 13 is considered similar to pediocin PA-1. PMID:25015266

Altunta?, Evrim Güne?; Ayhan, Kamuran; Peker, Selen; Ayhan, Beycan; Demiralp, Duygu Ozel

2014-10-01

374

Analysis of protein tyrosine phosphatase interactions with microarrayed phosphopeptide substrates using imaging mass spectrometry  

PubMed Central

Microarrays of peptide and recombinant protein libraries are routinely used for high-throughput studies of protein-protein interactions and enzymatic activities. Imaging mass spectrometry (IMS) is currently applied as a method to localize analytes on thin tissue sections and other surfaces. Here, we have applied IMS as a label-free means to analyze protein-peptide interactions in a microarray-based phosphatase assay. This IMS strategy visualizes the entire microarray in one composite image by collecting a pre-defined raster of MALDI-TOF MS spectra over the surface of the chip. Examining the bacterial tyrosine phosphatase YopH, we used IMS as a label-free means to visualize enzyme binding and activity with a microarrayed phosphopeptide library printed on chips coated with either gold or indium-tin oxide. Further, we demonstrate that microarray-based IMS can be coupled with surface plasmon resonance imaging to add kinetic analyses to measured binding interactions. The method described here is within the capabilities of many modern MALDI-TOF instruments and has general utility for the label-free analysis of microarray assays. PMID:23906642

McKee, Christopher J.; Hines, Harry B.; Ulrich, Robert G.

2013-01-01

375

MALDI-TOF mass spectrometry for the monitoring of she-donkey's milk contamination or adulteration.  

PubMed

Donkey's milk (DM), representing a safe and alternative food in both IgE-mediated and non-IgE-mediated cow's milk protein allergy, can be categorized as precious pharma-food. Moreover, an economically relevant interest for the use of DM in cosmetology is also developing. The detection of adulterations and contaminations of DM is a matter of fundamental importance from both an economic and allergenic standpoint, and, to this aim, fast and efficient analytical approaches to assess the authenticity of this precious nutrient are desirable. Here, a rapid matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS)-based method aimed to the detection of bovine or caprine milk in raw DM is reported. The presence of the extraneous milks was revealed by monitoring the protein profiles of the most abundant whey proteins, ?-lactalbumin (?-LA) and ?-lactoglobulin, used as molecular markers. The possibility of obtaining a quantitative analysis of the level of cow or goat milk in DM based on the MALDI-TOF peak areas of ?-LAs was also explored. The results showed that the experimental quantitative values were in good agreement with the real composition of each mixture. As pretreatment of the milk samples is not required, and owing to the speed and the high sensitivity of MALDI-MS, the protocol here reported could represent a reliable method for routine analyses aimed to assess the absence of contamination in raw fresh DM samples. PMID:23378086

Cunsolo, Vincenzo; Muccilli, Vera; Saletti, Rosaria; Foti, Salvatore

2013-02-01

376

Rapid Inactivation of Mycobacterium and Nocardia Species before Identification Using Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry.  

PubMed

The identification of mycobacteria outside biocontainment facilities requires that the organisms first be rendered inactive. Exposure to 70% ethanol (EtOH) either before or after mechanical disruption was evaluated in order to establish a safe, effective, and rapid inactivation protocol that is compatible