| 1. |
- Alseekh, Saleh, et al.
(författare)
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Mass spectrometry-based metabolomics: a guide for annotation, quantification and best reporting practices
- 2021
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Ingår i: Nature Methods. - : Springer Science and Business Media LLC. - 1548-7091 .- 1548-7105. ; 18:7, s. 747-756
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Forskningsöversikt (refereegranskat)abstract
- This Perspective, from a large group of metabolomics experts, provides best practices and simplified reporting guidelines for practitioners of liquid chromatography- and gas chromatography-mass spectrometry-based metabolomics. Mass spectrometry-based metabolomics approaches can enable detection and quantification of many thousands of metabolite features simultaneously. However, compound identification and reliable quantification are greatly complicated owing to the chemical complexity and dynamic range of the metabolome. Simultaneous quantification of many metabolites within complex mixtures can additionally be complicated by ion suppression, fragmentation and the presence of isomers. Here we present guidelines covering sample preparation, replication and randomization, quantification, recovery and recombination, ion suppression and peak misidentification, as a means to enable high-quality reporting of liquid chromatography- and gas chromatography-mass spectrometry-based metabolomics-derived data.
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| 2. |
- Cintron-Colon, Rigo, et al.
(författare)
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Activation of Kappa Opioid Receptor Regulates the Hypothermic Response to Calorie Restriction and Limits Body Weight Loss
- 2019
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 29:24, s. 4291-4299
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Tidskriftsartikel (refereegranskat)abstract
- Mammals maintain a nearly constant core body temperature (T-b) by balancing heat production and heat dissipation. This comes at a high metabolic cost that is sustainable if adequate calorie intake is maintained. When nutrients are scarce or experimentally reduced such as during calorie restriction (CR), endotherms can reduce energy expenditure by lowering T-b [1-6]. This adaptive response conserves energy, limiting the loss of body weight due to low calorie intake [710]. Here we show that this response is regulated by the kappa opioid receptor (KOR). CR is associated with increased hypothalamic levels of the endogenous opioid Leuenkephalin, which is derived from the KOR agonist precursor dynorphin [11]. Pharmacological inhibition of KOR, but not of the delta or the mu opioid receptor subtypes, fully blocked CR-induced hypothermia and increased weight loss during CR independent of calorie intake. Similar results were seen with DIO mice subjected to CR. In contrast, inhibiting KOR did not change T-b in animals fed ad libitum (AL). Chemogenetic inhibition of KOR neurons in the hypothalamic preoptic area reduced the CR-induced hypothermia, whereas chemogenetic activation of prodynorphin-expressing neurons in the arcuate or the parabrachial nucleus lowered T-b. These data indicate that KOR signaling is a pivotal regulator of energy homeostasis and can affect body weight during dieting by modulating T-b and energy expenditure.
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| 3. |
- Domingo-Almenara, Xavier, et al.
(författare)
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CMS-MRM and METLIN-MRM : a cloud library and public resource for targeted analysis of small molecules
- 2018
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Ingår i: Nature Methods. - : Nature Publishing Group. - 1548-7091 .- 1548-7105. ; 15:9, s. 681-
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Tidskriftsartikel (refereegranskat)abstract
- We report XCMS-MRM and METLIN-MRM (http://xcmsonline-mrm.scripps.edu/ and http://metlin.scripps.edu/), a cloud-based data-analysis platform and a public multiple-reaction monitoring (MRM) transition repository for small-molecule quantitative tandem mass spectrometry. This platform provides MRM transitions for more than 15,500 molecules and facilitates data sharing across different instruments and laboratories.
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| 4. |
- Go, Eden P, et al.
(författare)
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Mass spectrometry reveals specific and global molecular transformations during viral infection.
- 2006
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 5:9, s. 2405-16
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Tidskriftsartikel (refereegranskat)abstract
- Mass spectrometry analysis was used to target three different aspects of the viral infection process: the expression kinetics of viral proteins, changes in the expression levels of cellular proteins, and the changes in cellular metabolites in response to viral infection. The combination of these methods represents a new, more comprehensive approach to the study of viral infection revealing the complexity of these events within the infected cell. The proteins associated with measles virus (MV) infection of human HeLa cells were measured using a label-free approach. On the other hand, the regulation of cellular and Flock House Virus (FHV) proteins in response to FHV infection of Drosophila cells was monitored using stable isotope labeling. Three complementary techniques were used to monitor changes in viral protein expression in the cell and host protein expression. A total of 1500 host proteins was identified and quantified, of which over 200 proteins were either up- or down-regulated in response to viral infection, such as the up-regulation of the Drosophila apoptotic croquemort protein, and the down-regulation of proteins that inhibited cell death. These analyses also demonstrated the up-regulation of viral proteins functioning in replication, inhibition of RNA interference, viral assembly, and RNA encapsidation. Over 1000 unique metabolites were also observed with significant changes in over 30, such as the down-regulated cellular phospholipids possibly reflecting the initial events in cell death and viral release. Overall, the cellular transformation that occurs upon viral infection is a process involving hundreds of proteins and metabolites, many of which are structurally and functionally uncharacterized.
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| 5. |
- Go, Eden P, et al.
(författare)
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Selective metabolite and peptide capture/mass detection using fluorous affinity tags.
- 2007
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 6:4, s. 1492-9
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Tidskriftsartikel (refereegranskat)abstract
- A new and general methodology is described for the targeted enrichment and subsequent direct mass spectrometric characterization of sample subsets bearing various chemical functionalities from highly complex mixtures of biological origin. Specifically, sample components containing a chemical moiety of interest are first selectively labeled with perfluoroalkyl groups, and the entire sample is then applied to a perfluoroalkyl-silylated porous silicon (pSi) surface. Due to the unique hydrophobic and lipophobic nature of the perfluorinated tags, unlabeled sample components are readily removed using simple surface washes, and the enriched sample fraction can then directly be analyzed by desorption/ionization on silicon mass spectrometry (DIOS-MS). Importantly, this fluorous-based enrichment methodology provides a single platform that is equally applicable to both peptide as well as small molecule focused applications. The utility of this technique is demonstrated by the enrichment and mass spectrometric analysis of both various peptide subsets from protein digests as well as amino acids from serum.
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| 6. |
- Nordström, Anders, et al.
(författare)
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Multiple ionization mass spectrometry strategy used to reveal the complexity of metabolomics.
- 2008
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 80:2, s. 421-9
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Tidskriftsartikel (refereegranskat)abstract
- A multiple ionization mass spectrometry strategy is presented based on the analysis of human serum extracts. Chromatographic separation was interfaced inline with the atmospheric pressure ionization techniques electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in both positive (+) and negative (-) ionization modes. Furthermore, surface-based matrix-assisted laser desorption/ionization (MALDI) and desorption ionization on silicon (DIOS) mass spectrometry were also integrated with the separation through fraction collection and offline mass spectrometry. Processing of raw data using the XCMS software resulted in time-aligned ion features, which are defined as a unique m/z at a unique retention time. The ion feature lists obtained through LC-MS with ESI and APCI interfaces in both +/- ionization modes were compared, and unique ion tables were generated. Nonredundant, unique ion features, were defined as mass numbers for which no mass numbers corresponding to [M + H](+), [M - H](-), or [M + Na](+) were observed in the other ionization methods at the same retention time. Analysis of the extracted serum using ESI for both (+) and (-) ions resulted in >90% additional unique ions being detected in the (-) ESI mode. Complementing the ESI analysis with APCI resulted in an additional approximately 20% increase in unique ions. Finally, ESI/APCI ionization was combined with fraction collection and offline-MALDI and DIOS mass spectrometry. The parts of the total ion current chromatograms in the LC-MS acquired data corresponding to collected fractions were summed, and m/z lists were compiled and compared to the m/z lists obtained from the DIOS/MALDI spectra. It was observed that, for each fraction, DIOS accounted for approximately 50% of the unique ions detected. These results suggest that true global metabolomics will require multiple ionization technologies to address the inherent metabolite diversity and therefore the complexity in and of metabolomics studies.
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| 7. |
- Nordström, Anders, et al.
(författare)
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Nonlinear data alignment for UPLC-MS and HPLC-MS based metabolomics : quantitative analysis of endogenous and exogenous metabolites in human serum.
- 2006
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 78:10, s. 3289-95
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Tidskriftsartikel (refereegranskat)abstract
- A nonlinear alignment strategy was examined for the quantitative analysis of serum metabolites. Two small-molecule mixtures with a difference in relative concentration of 20-100% for 10 of the compounds were added to human serum. The metabolomics protocol using UPLC and XCMS for LC-MS data alignment could readily identify 8 of 10 spiked differences among more than 2700 features detected. Normalization of data against a single factor obtained through averaging the XCMS integrated response areas of spiked standards increased the number of identified differences. The original data structure was well preserved using XCMS, but reintegration of identified differences in the original data reduced the number of false positives. Using UPLC for separation resulted in 20% more detected components compared to HPLC. The length of the chromatographic separation also proved to be a crucial parameter for a number of detected features. Moreover, UPLC displayed better retention time reproducibility and signal-to-noise ratios for spiked compounds over HPLC, making this technology more suitable for nontargeted metabolomics applications.
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| 8. |
- Nordström, Anders, et al.
(författare)
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Surfactant-enhanced desorption/ionization on silicon mass spectrometry.
- 2006
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 78:1, s. 272-8
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Tidskriftsartikel (refereegranskat)abstract
- Perfluorinated surfactants are demonstrated to dramatically enhance desorption/ionization on fluorinated silicon (DIOS) mass spectrometry. Perfluorooctanesulfonic acid improved the signal-to-noise ratio of tryptic digests and gave a 3-fold increase in the number of peptides identified. Similar results were also obtained using perfluoroundecanoic acid; yet among the seven different surfactants tested, controls such as nonfluorinated sodium dodecyl sulfate or fluorinated molecules with minimal surfactant activity did not enhance the signal. The same surfactants also enhanced the DIOS-MS signal of amino acids, carbohydrates, and other small organic compounds. The signal enhancement may be facilitated by the high surface activity of the perfluorinated surfactants on the fluorinated silicon surfaces allowing for a higher concentration of analyte to be absorbed.
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| 9. |
- Northen, Trent R, et al.
(författare)
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Clathrate nanostructures for mass spectrometry.
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 449:7165, s. 1033-6
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Tidskriftsartikel (refereegranskat)abstract
- The ability of mass spectrometry to generate intact biomolecular ions efficiently in the gas phase has led to its widespread application in metabolomics, proteomics, biological imaging, biomarker discovery and clinical assays (namely neonatal screens). Matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization have been at the forefront of these developments. However, matrix application complicates the use of MALDI for cellular, tissue, biofluid and microarray analysis and can limit the spatial resolution because of the matrix crystal size (typically more than 10 mum), sensitivity and detection of small compounds (less than 500 Da). Secondary-ion mass spectrometry has extremely high lateral resolution (100 nm) and has found biological applications although the energetic desorption/ionization is a limitation owing to molecular fragmentation. Here we introduce nanostructure-initiator mass spectrometry (NIMS), a tool for spatially defined mass analysis. NIMS uses 'initiator' molecules trapped in nanostructured surfaces or 'clathrates' to release and ionize intact molecules adsorbed on the surface. This surface responds to both ion and laser irradiation. The lateral resolution (ion-NIMS about 150 nm), sensitivity, matrix-free and reduced fragmentation of NIMS allows direct characterization of peptide microarrays, direct mass analysis of single cells, tissue imaging, and direct characterization of blood and urine.
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| 10. |
- Northen, Trent R, et al.
(författare)
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High surface area of porous silicon drives desorption of intact molecules.
- 2007
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Ingår i: Journal of the American Society for Mass Spectrometry. - : American Chemical Society (ACS). - 1044-0305 .- 1879-1123. ; 18:11, s. 1945-9
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Tidskriftsartikel (refereegranskat)abstract
- The surface structure of porous silicon used in desorption/ionization on porous silicon (DIOS) mass analysis is known to play a primary role in the desorption/ionization (D/I) process. In this study, mass spectrometry and scanning electron microscopy (SEM) are used to examine the correlation between intact ion generation with surface ablation and surface morphology. The DIOS process is found to be highly laser energy dependent and correlates directly with the appearance of surface ions (Si(n)(+) and OSiH(+)). A threshold laser energy for DIOS is observed (10 mJ/cm(2)), which supports that DIOS is driven by surface restructuring and is not a strictly thermal process. In addition, three DIOS regimes are observed that correspond to surface restructuring and melting. These results suggest that higher surface area silicon substrates may enhance DIOS performance. A recent example that fits into this mechanism is the surface of silicon nanowires, which has a high surface energy and concomitantly requires lower laser energy for analyte desorption.
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