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2022 ◽  
Author(s):  
Darian Smercina ◽  
Young-Mo Kim ◽  
Mary Lipton ◽  
Dusan Velickovic ◽  
Kirsten Hofmockel

Soil microorganisms drive ecosystem function, but challenges of scale between microbe and ecosystem hinder our ability to accurately quantify and predictively model the soil microbe-ecosystem function relationship. Quantifying this relationship necessitates studies that systematically characterize multi-omics of soil microorganisms and their activity across sampling scales from spatially resolved to bulk measures, and structural complexity, from liquid pure culture to in situ. To address this need, we cultured two diazotrophic bacteria in liquid and solid media, with and without nitrogen (N) to quantify differences in extracellular metabolites associated with nitrogen fixation under increasing environmental structural complexity. We also quantified extracellular metabolites across sampling scales including bulk sampling via GC-MS analysis and spatially resolved analysis via MALDI mass spectrometry imaging. We found extracellular production of inorganic and organic N during free-living nitrogen fixation activity, highlighting a key mechanism of terrestrial N contributions from this process. Additionally, our results emphasize the need to consider the structural complexity of the environment and spatial scale when quantifying microbial activity. We found differences in metabolite profiles between culture conditions, supporting previous work indicating environmental structure influences microbial function, and across scales, underscoring the need to quantify microbial scale conditions to accurately interpret microbial function.


Author(s):  
Aleksandr S. Taraskin ◽  
Konstantin K. Semenov ◽  
Alexey A. Lozhkov ◽  
Irina L. Baranovskaya ◽  
Aleksandr V. Protasov ◽  
...  

2021 ◽  
Author(s):  
Julia Kokesch-Himmelreich ◽  
Oliver Wittek ◽  
Alan M. Race ◽  
Sophie Rakete ◽  
Claus Schlicht ◽  
...  

Mass Spectrometry imaging (MS imaging) provides spatial information for a wide range of compound classes in different sample matrices. We used MS imaging to investigate the distribution of components in fresh and processed food, including meat, dairy and bakery products. The MS imaging workflow was optimized to cater to the specific properties and challenges of the individual samples. We successfully detected highly nonpolar and polar constituents such as beta-carotene and anthocyanins, respectively. For the first time, the distribution of a contaminant and a food additive was visualized in processed food. We detected acrylamide in German gingerbread and investigated the penetration of the preservative natamycin into cheese. For this purpose, a new data analysis tool was developed to study the penetration of analytes from uneven surfaces. Our results show that MS imaging has great potential in food analysis to provide relevant information about components' distributions, particularly those underlying official regulations.


Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2235
Author(s):  
Makhmut Yakubov ◽  
Guzalia Abilova ◽  
Elvira Tazeeva ◽  
Svetlana Yakubova ◽  
Damir Tazeev ◽  
...  

The composition of purified vanadyl porphyrins recovered from the resins of heavy oils possessing high and low vanadium contents was investigated. Vanadium content in the resins of the heavy oils under study differs by a factor of ca. 15. To recover and purify vanadyl porphyrins from the resins, extraction by N,N–dimethylformamide (DMF) with subsequent two-stage column chromatography on silica gel and sulfocationite were employed. The change of structural-group composition and content of vanadyl porphyrins in the products obtained at each stage was evaluated using Fourier IR and UV-Vis spectroscopy. Analysis of the purified vanadyl porphyrins using MALDI mass spectrometry determined distribution of their most abundant types (etio- and DPEP) and identified C27–C39 homologs for the resins possessing high vanadium content and C28–C39 homologs for the resins with low vanadium content.


Author(s):  
Pegah Khamehgir-Silz ◽  
Stefanie Gerbig ◽  
Nadine Volk ◽  
Sabine Schulz ◽  
Bernhard Spengler ◽  
...  

Abstract The distribution of atherosclerotic lesions in the aorta and its branches of ApoE knockout (ApoE−/−) mice is like that of patients with atherosclerosis. By using high-resolution MALDI mass spectrometry imaging (MSI), we aimed at characterizing universally applicable physiological biomarkers by comparing the murine lipid marker profile with that of human atherosclerotic arteries. Therefore, the aorta or carotid artery of male ApoE−/− mice at different ages, human arteries with documented atherosclerotic changes originated from amputated limbs, and corresponding controls were analysed. Obtained data were subjected to multivariate statistical analysis to identify potential biomarkers. Thirty-one m/z values corresponding to individual lipid species of cholesterol esters, lysophosphatidylcholines, lysophosphatidylethanolamines, and cholesterol derivatives were found to be specific in aortic atherosclerotic plaques of old ApoE−/− mice. The lipid composition at related vessel positions of young ApoE−/− mice was more comparable with wild-type mice. Twenty-six m/z values of the murine lipid markers were found in human atherosclerotic peripheral arteries but also control vessels and showed a more patient-dependent diverse distribution. Extensive data analysis without marker preselection based on mouse data revealed lysophosphatidylcholine and glucosylated cholesterol species, the latter not being detected in the murine atherosclerotic tissue, as specific potential novel human atherosclerotic vessel markers. Despite the heterogeneous lipid profile of atherosclerotic peripheral arteries derived from human patients, we identified lipids specifically colocalized to atherosclerotic human tissue and plaques in ApoE−/− mice. These data highlight species-dependent differences in lipid profiles between peripheral artery disease and aortic atherosclerosis.


2021 ◽  
Vol 22 (22) ◽  
pp. 12393
Author(s):  
Elvira Sgobba ◽  
Yohann Daguerre ◽  
Marco Giampà

Classic metabolomic methods have proven to be very useful to study functional biology and variation in the chemical composition of different tissues. However, they do not provide any information in terms of spatial localization within fine structures. Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI) does and reaches at best a spatial resolution of 0.25 μm depending on the laser setup, making it a very powerful tool to analyze the local complexity of biological samples at the cellular level. Here, we intend to give an overview of the diversity of the molecules and localizations analyzed using this method as well as to update on the latest adaptations made to circumvent the complexity of samples. MALDI MSI has been widely used in medical sciences and is now developing in research areas as diverse as entomology, microbiology, plant biology, and plant–microbe interactions, the rhizobia symbiosis being the most exhaustively described so far. Those are the fields of interest on which we will focus to demonstrate MALDI MSI strengths in characterizing the spatial distributions of metabolites, lipids, and peptides in relation to biological questions.


2021 ◽  
Author(s):  
◽  
Rana Fathizargaran

<p>Gliotoxin is a secondary metabolite that is produced by several species of fungi, and is toxic to mammalian cells. It is immunosuppressive, affects antigen presentation by macrophages, and causes apoptosis of some cells. Gliotoxin is an epipolythiodioxopiperazine molecule and contains an internal disulfide bridge that is highly reactive and essential for its toxicity. Suggested mechanisms of action include modification of thiol groups of cysteine residues in target proteins by generating oxidative stress or through covalent modification. The goal of this project was to develop mass spectrometry methods to detect protein modification by gliotoxin. Creatine kinase was used as a model protein. The measured mass of creatine kinase from 45 spectra gave a mean of 42,944 ± 24 which was consistent with the predicted mass of creatine kinase. A tryptic digest of creatine kinase indicated ions consistent with the predicted masses of the four cys-containing peptides including abundant ions at m/z 794, 1130 and 2870 and an ion at low intensity at 4373. The reaction of creatine kinase with gliotoxin showed a time dependent reaction that after 14 h was consistent with formation of a gliotoxin adduct. Reduction of the product with dithiothreitol released creatine kinase. Analysis of the tryptic peptides using MALDI mass spectrometry indicated complex modification of cysteines possibly including formation of a mixed disulfide adduct, intramolecular disulfides of CK, and sulfur oxidation products. Further analysis using the ICAT (isotope-coded affinity tag) method suggested modification of Cys-254 and Cys-283 by gliotoxin. Preliminary experiments examined the effects of gliotoxin on HL-60 cells using ICAT. Proteins of gliotoxin-treated and untreated cells were labeled with Heavy and Light ICAT reagents. Potential ICAT pairs were detected in the mass spectrum as a preliminary search for proteins affected by gliotoxin. The results indicate that ICAT labeling should be an effective strategy for characterization of the protein targets of gliotoxin.</p>


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