scholarly journals Quantitative mass spectrometry for human melanocortin peptides in vitro and in vivo suggests prominent roles for β-MSH and desacetyl α-MSH in energy homeostasis

2018 ◽  
Vol 17 ◽  
pp. 82-97 ◽  
Author(s):  
Peter Kirwan ◽  
Richard G. Kay ◽  
Bas Brouwers ◽  
Vicente Herranz-Pérez ◽  
Magdalena Jura ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Energy Homeostasis ◽  
Quantitative Mass Spectrometry ◽  
Melanocortin Peptides

scholarly journals Towards quantitative mass spectrometry-based metabolomics in microbial and mammalian systems

2016 ◽  
Vol 374 (2079) ◽  
pp. 20150363 ◽  
Author(s):  
Rahul Vijay Kapoore ◽  
Seetharaman Vaidyanathan
Keyword(s):  
Mass Spectrometry ◽  
Molecular Weight ◽  
Biological Systems ◽  
High Sensitivity ◽  
Quantitative Mass Spectrometry ◽  
Small Molecular Weight ◽  
Quantitative Changes ◽  
Analytical Approaches

Metabolome analyses are a suite of analytical approaches that enable us to capture changes in the metabolome (small molecular weight components, typically less than 1500 Da) in biological systems. Mass spectrometry (MS) has been widely used for this purpose. The key challenge here is to be able to capture changes in a reproducible and reliant manner that is representative of the events that take place in vivo . Typically, the analysis is carried out in vitro , by isolating the system and extracting the metabolome. MS-based approaches enable us to capture metabolomic changes with high sensitivity and resolution. When developing the technique for different biological systems, there are similarities in challenges and differences that are specific to the system under investigation. Here, we review some of the challenges in capturing quantitative changes in the metabolome with MS based approaches, primarily in microbial and mammalian systems. This article is part of the themed issue ‘Quantitative mass spectrometry’.

Identification of novel α-gliadin genes

Genome ◽  
2011 ◽  
Vol 54 (3) ◽  
pp. 244-252 ◽  
Author(s):  
Peng-Fei Qi ◽  
Yu-Ming Wei ◽  
Qing Chen ◽  
Thérèse Ouellet ◽  
Jia Ai ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Triticum Aestivum L ◽  
Protein Band ◽  
Cysteine Residues ◽  
Disulphide Bonds ◽  
Chain Extenders ◽  
Domain I ◽  
Unique Domain

Ten novel α-gliadin genes (Gli-ta, Gli-turg1, Gli-turg2, Gli-turg3, Gli-turg4, Gli-turg5, Gli-turg6, Gli-cs1, Gli-cs2, and Gli-cs3) with unique characteristics were isolated from wheat ( Triticum aestivum L.), among which Gli-cs1, Gli-cs2, Gli-cs3, and Gli-turg6 were pseudogenes. Gli-cs3 and nine other sequences were much larger and smaller, respectively, than the typical α-gliadins. This variation was caused by insertion or deletion of the unique domain I and a polyglutamine region, possibly the result of illegitimate recombination. Consequently, Gli-cs3 contained 10 cysteine residues, whereas there were 2 cysteine residues only in the other nine sequences. Gli-ta/Gli-ta-like α-gliadin genes are normally expressed during the development of seeds. SDS–PAGE analysis showed that in-vitro-expressed Gli-ta could form intermolecular disulphide bonds and could be chain extenders. A protein band similar in size to Gli-ta has been observed in seed extracts, and mass spectrometry results confirm that the band contains small molecular mass α-gliadins, which is a characteristic of the novel α-gliadins. Mass spectrometry results also indicated that the two cysteine residues of Gli-ta/Gli-ta-like proteins participated in the formation of intermolecular disulphide bonds in vivo.

scholarly journals Multiplatform Physiologic and Metabolic Phenotyping Reveals Microbial Toxicity

mSystems ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
Jingwei Cai ◽  
Robert G. Nichols ◽  
Imhoi Koo ◽  
Zachary A. Kalikow ◽  
Limin Zhang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Flow Cytometry ◽  
Free Radical ◽  
Gut Microbiota ◽  
Structure And Function ◽  
Metabolic Phenotyping ◽  
And Function

ABSTRACTThe gut microbiota is susceptible to modulation by environmental stimuli and therefore can serve as a biological sensor. Recent evidence suggests that xenobiotics can disrupt the interaction between the microbiota and host. Here, we describe an approach that combinesin vitromicrobial incubation (isolated cecal contents from mice), flow cytometry, and mass spectrometry- and1H nuclear magnetic resonance (NMR)-based metabolomics to evaluate xenobiotic-induced microbial toxicity. Tempol, a stabilized free radical scavenger known to remodel the microbial community structure and functionin vivo, was studied to assess its direct effect on the gut microbiota. The microbiota was isolated from mouse cecum and was exposed to tempol for 4 h under strict anaerobic conditions. The flow cytometry data suggested that short-term tempol exposure to the microbiota is associated with disrupted membrane physiology as well as compromised metabolic activity. Mass spectrometry and NMR metabolomics revealed that tempol exposure significantly disrupted microbial metabolic activity, specifically indicated by changes in short-chain fatty acids, branched-chain amino acids, amino acids, nucleotides, glucose, and oligosaccharides. In addition, a mouse study with tempol (5 days gavage) showed similar microbial physiologic and metabolic changes, indicating that thein vitroapproach reflectedin vivoconditions. Our results, through evaluation of microbial viability, physiology, and metabolism and a comparison ofin vitroandin vivoexposures with tempol, suggest that physiologic and metabolic phenotyping can provide unique insight into gut microbiota toxicity.IMPORTANCEThe gut microbiota is modulated physiologically, compositionally, and metabolically by xenobiotics, potentially causing metabolic consequences to the host. We recently reported that tempol, a stabilized free radical nitroxide, can exert beneficial effects on the host through modulation of the microbiome community structure and function. Here, we investigated a multiplatform phenotyping approach that combines high-throughput global metabolomics with flow cytometry to evaluate the direct effect of tempol on the microbiota. This approach may be useful in deciphering how other xenobiotics directly influence the microbiota.

Mass spectrometry-based circulating IgA1 complexes screening driven identification of IgA-alpha-1-microglobulin complex in IgA nephropathy

2020 ◽  
Author(s):  
Boyang Xu ◽  
Li Zhu ◽  
Qingsong Wang ◽  
Yanfeng Zhao ◽  
Meng Jia ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Iga Nephropathy ◽  
Cell Injury ◽  
Mesangial Cell ◽  
Mesangial Cells ◽  
Independent Population ◽  
Tubulointerstitial Lesions ◽  
Noninvasive Biomarker

Abstract Background IgA nephropathy (IgAN) is characterized by predominant IgA deposition in the glomerular mesangium. Previous studies proved that renal-deposited IgA in IgAN came from circulating IgA1-containing complexes (CICs). Methods To explore the composition of CICs in IgAN, we isolated CICs from IgAN patients and healthy controls, and then quantitatively analyzed them by mass spectrometry. Meanwhile, the isolated CICs were used to treat human mesangial cells to monitor mesangial cell injury. Taken together the proteins content and injury effects, the key constituent in CICs was identified. Then, the circulating levels of identified key constituent-IgA complex were detected in an independent population by an in-house-developed ELISA. Results By comparing the proteins of CICs between IgAN patients and controls, we found that 14 proteins showed significantly different levels. Among them, alpha-1-microglobulin content in CICs was associated with not only in vitro mesangial cell proliferation and MCP-1 secretion but also in vivo eGFR levels and tubulointerstitial lesions in IgAN patients. Moreover, we found alpha-1-microglobulin was prone to bind aberrant glycosylated IgA1. Additionally, an elevated circulating IgA-alpha-1-microglobulin complex levels were detected in an independent IgAN population, and IgA-alpha-1-microglobulin complex levels were correlated with hypertension, eGFR levels and Oxford-T scores in these IgAN patients. Conclusions Our results suggest that the IgA-alpha-1-microglobulin complex is an important constituent in CICs, and that circulating IgA-alpha-1-microglobulin complex detection might serve as a potential noninvasive biomarker detection method for IgAN.

scholarly journals Bile Acids Quantification by Liquid Chromatography–Tandem Mass Spectrometry: Method Validation, Reference Range, and Interference Study

Diagnostics ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 462 ◽  
Author(s):  
Elisa Danese ◽  
Davide Negrini ◽  
Mairi Pucci ◽  
Simone De Nitto ◽  
Davide Ambrogi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Healthy Subjects ◽  
Reference Range ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Interference Study

Bile acids (BA) play a pivotal role in cholesterol metabolism. Their blood concentration has also been proposed as new prognostic and diagnostic indicator of hepatobiliary, intestinal, and cardiovascular disease. Liquid chromatography tandem mass spectrometry (LC–MS/MS) currently represents the gold standard for analysis of BA profile in biological samples. We report here development and validation of a LC–MS/MS technique for simultaneously quantifying 15 BA species in serum samples. We also established a reference range for adult healthy subjects (n = 130) and performed a preliminary evaluation of in vitro and in vivo interference. The method displayed good linearity, with high regression coefficients (>0.99) over a range of 5 ng/mL (lower limit of quantification, LLOQ) and 5000 ng/mL for all analytes tested. The accuracies were between 85–115%. Both intra- and inter-assay imprecision was <10%. The recoveries ranged between 92–110%. Each of the tested BA species (assessed on three concentrations) were stable for 15 days at room temperature, 4 °C, and −20 °C. The in vitro study did not reveal any interference from triglycerides, bilirubin, or cell-free hemoglobin. The in vivo interference study showed that pools obtained from hyper-cholesterolemic patients and hyper-bilirubinemic patients due to post-hepatic jaundice for benign cholestasis, cholangiocarcinoma and pancreatic head tumors had clearly distinct patterns of BA concentrations compared with a pool obtained from samples of healthy subjects. In conclusion, this study proposes a new suitable candidate method for identification and quantitation of BA in biological samples and provides new insight into a number of variables that should be taken into account when investigating pathophysiological changes of BA in human diseases.

scholarly journals Reactions of Microorganisms with Atomic Oxygen Radical Anions: Damage of Cells and Irreversible Inactivation

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Longchun Li ◽  
Fan Wu ◽  
Yu Chen ◽  
Lei Xu ◽  
Xiaochang Hao ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Atomic Oxygen ◽  
Oxygen Radical ◽  
Initial Population ◽  
Structure Changes ◽  
Volatile Products ◽  
Before And After ◽  
Inactivation Mechanism

Reactive oxygen species play important effects on organisms not only in vivo but also in vitro. The atomic oxygen radical anion (O-) has shown extremely high oxidation and reactivity towards small molecules of hydrocarbons. However, the O- effects on cells of microorganisms are scarcely investigated. This work showed the evidence that O- could react quickly with microorganisms (Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Aspergillus niger, Saccharomyces cerevisiae, and Actinomycetes (5046)) and damaged the cell walls seriously as well as their intrinsic structures, arising a fast and irreversible inactivation. SEM and TEM micrographs were used to reveal the structure changes of cells before and after reacting with O- radicals. The inactivation efficiencies of the microorganisms depended on the O- intensity, the initial population of microorganisms, the exposed area, the environment, and the microorganisms’ types. Over 99% reduction of an initial 1.0×107 colony-forming unit (cfu), E. coli population only required less than 2 minutes while exposed to a 0.23 μA/cm2 O- flux under dry argon atmosphere (30°C, 1 atm). The observation of anionic intermediates (CO-, CO2-, H2O-, and anionic hydrocarbons) by time-of-flight (TOF) mass spectrometry and the neutral volatile products (CO, CO2, and H2O) by quadrupole mass spectrometry (Q-MS) provided an evidence of the reactions of O- with hydrocarbon bonds of the microorganisms. The inactivation mechanism of microorganisms induced by O- was discussed.

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