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https://www.readbyqxmd.com/read/29792715/quantitative-analysis-of-peptide-matrix-interactions-in-lyophilized-solids-using-photolytic-labeling
#1
Yuan Chen, Elizabeth M Topp
Peptide-matrix interactions in lyophilized solids were explored using photolytic labeling and reversed phase high performance liquid chromatography (rp-HPLC) and mass spectrometric (MS) analysis. A model peptide (Ac-QELHKLQ-NHCH3 ) derived from salmon calcitonin was first labeled with a heterobifunctional cross-linker NHS-diazirine (succinimidyl 4,4'-azipentanoate; SDA) at Lys5 in solution, with ~ 100% conversion. The SDA labeled peptide was then formulated with the following excipients at a 1:400 molar ratio and lyophilized: sucrose, trehalose, mannitol, histidine, arginine, urea and NaCl...
May 24, 2018: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/29790754/epiprofile-2-0-a-computational-platform-for-processing-epi-proteomics-mass-spectrometry-data
#2
Zuo-Fei Yuan, Simone Sidoli, Dylan M Marchione, Johayra Simithy, Kevin A Janssen, Mary R Szurgot, Benjamin A Garcia
Epigenetics has become a fundamental scientific discipline with various implications for biology and medicine. Epigenetic marks, mostly DNA methylation and histone post-translational modifications (PTMs), play important roles in chromatin structure and function. Accurate quantification of these marks is an ongoing challenge due to the variety of modifications and their wide dynamic range of abundance. Here, we present EpiProfile 2.0, an extended version of our 2015 software (v1.0) for accurate quantification of histone peptides based on liquid chromatography - tandem mass spectrometry (LC-MS/MS) analysis...
May 23, 2018: Journal of Proteome Research
https://www.readbyqxmd.com/read/29790616/in-vitro-and-in-vivo-metabolic-profiles-of-fasiglifam-by-using-ultra-high-performance-liquid-chromatography-combined-with-q-exactive-orbitrap-tandem-mass-spectrometry
#3
Jin-Qi Li, Jia-Feng Wang, Jie Li, Shu-Han Zhang, Dan He, Rong-Sheng Tong, Shu-Ya She
RATIONALE: Fasiglifam is an orally available and selective partial agonist of hGPR40 receptor, which was unexpectedly terminated at phase III clinical trials due to its severe hepatotoxicity. To fully understand its mechanism of action, it is necessary to investigate the in vitro and in vivo metabolic profiles of fasiglifam. METHODS: For in vitro metabolism, fasiglifam was incubated with rat or human liver microsomes in the presence of NADPH, GSH and UDPGA for 60 min...
May 23, 2018: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/29790297/selected-cardoon-cynara-cardunculus-l-genotypes-suitable-for-pdo-cheeses-in-mediterranean-regions
#4
Paulo Barracosa, Nuno Rosa, Marlene Barros, Euclides Pires
Cardoon flower extract is a traditional and exclusive rennet used for some PDO cheeses in several Mediterranean regions, due its extremely high concentration in cardosins. In this preliminary study, six individual cardoon genotypes (1M-6M) were selected because they revealed a wide and consistent diversity of total and specific cardosin concentrations in flowers. During three growing seasons the stability of twelve biochemical characteristics of flower extracts and twenty-six plant morphological descriptors was confirmed...
May 22, 2018: Chemistry & Biodiversity
https://www.readbyqxmd.com/read/29789171/n-propyl-n-2-pyridylurea-modified-silica-as-mixed-mode-stationary-phase-with-moderate-weak-anion-exchange-capacity-and-ph-dependent-surface-charge-reversal
#5
Stefanie Bäurer, Stefan Polnick, Orlando L Sánchez-Muñoz, Markus Kramer, Michael Lämmerhofer
Herein, we present a novel silica-based stationary phase modified with N-propyl-N'-2-pyridylurea selector. Due to the weakly basic properties of the pyridine selector and the presence of residual silanols after selector immobilization, a zwitterionic surface with a pI observed at approximately pH 5.5 was measured by electrophoretic light scattering in pH-dependent ζ-potential determinations. The capability of the new N-propyl-N'-2-pyridylurea-modified silica to serve as mixed-mode stationary phase was investigated...
May 7, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29788543/a-new-glutathione-conjugate-of-the-pyrrolizidine-alkaloids-produced-by-human-cytosolic-enzyme-dependent-reactions-in-vitro
#6
Fashe Muluneh, Merja R Häkkinen, Rami El-Dairi, Markku Pasanen, Risto O Juvonen
RATIONALE: The toxic metabolites of pyrrolizidine alkaloids (PAs) are initially formed by cytochrome P450 mediated oxidation reactions and primarily eliminated as glutathione (GSH) conjugates. Although the reaction between the reactive metabolites and GSH can occur spontaneously, the role of the cytosolic enzymes in the process has not been studied. METHODS: The toxic metabolites of selected PAs (retrorsine, monocrotaline, senecionine, lasiocarpine, heliotrine or senkirkine) were generated by incubating them in 100 mM phosphate buffer pH 7...
May 22, 2018: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/29787687/rapid-determination-of-polar-pesticides-and-plant-growth-regulators-in-fruits-and-vegetables-by-liquid-chromatography-tandem-mass-spectrometry
#7
Narong Chamkasem
A simple high-throughput liquid chromatography/tandem mass spectrometry (LC-MS/MS) multiresidue analysis method was developed for the simultaneous determination of polar pesticides, plant growth regulators and other polar compounds. These included amitrole, chlormequat, mepiquat, cyromazine, ETU, PTU, perchlorate, and daminozide using a mixed-mode column. A 10 g test portion was shaken with acidified methanol for 10 min. After centrifugation, the sample extract was injected and analyzed within 11 min by LC-MS-MS...
May 22, 2018: Journal of Environmental Science and Health. Part. B, Pesticides, Food Contaminants, and Agricultural Wastes
https://www.readbyqxmd.com/read/29787602/endocrine-disrupting-potency-of-organic-pollutant-mixtures-isolated-from-commercial-fish-oil-evaluated-in-yeast-based-bioassays
#8
Marek Łukasz Roszko, Marta Kamińska, Krystyna Szymczyk, Katarzyna Piasecka-Jóźwiak, Beata Chabłowska
The aim of this work was to evaluate the activity of xenobiotic mixtures containing persistent organic pollutants isolated from commercial fish oil samples against sex hormone receptors, including estrogen and androgen. The applied bioassay was based on transgenic yeast strains. The mixtures were extracted from the samples using the semi-permeable membrane dialysis technique and analyzed with gas chromatography/ion trap mass spectrometry. It turned out that mixtures of chemicals isolated from fish oil may interact with human steroid sex hormone receptors in various ways: the tested samples showed both estrogenic and anti-androgenic activity...
2018: PloS One
https://www.readbyqxmd.com/read/29785755/energy-resolved-mass-spectrometry-of-chlorogenic-acids-and-its-application-to-isomer-quantification-by-direct-infusion-tandem-mass-spectrometry
#9
Javier Hernandez, Anja Müller, Rakesh Jaiswal, Juan Z Davalos, Nikolai Kuhnert
INTRODUCTION: With the advent of high-perfomance liquid chromatography (HPLC)-tandem mass spectrometry (MS) using ion trap mass analysers it is possible to acquire unambigious structural information in particular with respect to aspects of regiochemistry and stereochemistry of organic compounds present in complex mixtures such as coffee extracts. However, HPLC-MS methods are resource extensive, laborious and lacking user friendliness. OBJECTIVE: To introduce a simple parameter - the energy threshhold for fragmentation - determined using energy resolved MS and demonstrate its value for the complete structural characterisation and even relative quantification of individual isomeric chlrogenic acids in direct infusion experiments...
May 21, 2018: Phytochemical Analysis: PCA
https://www.readbyqxmd.com/read/29785671/agarolytic-culturable-bacteria-associated-with-three-antarctic-subtidal-macroalgae
#10
Verónica Sánchez Hinojosa, Joel Asenjo, Sergio Leiva
Bacterial communities of Antarctic marine macroalgae remain largely underexplored in terms of diversity and biotechnological applications. In this study, three Antarctic subtidal macroalgae (Himantothallus grandifolius, Pantoneura plocamioides and Plocamium cartilagineum), two of them endemic of Antarctica, were investigated as a source for isolation of agar-degrading bacteria. A total of 21 epiphytic isolates showed agarolytic activity at low temperature on agar plates containing agar as the sole carbon source...
May 21, 2018: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/29784595/comparative-proteome-analysis-of-the-capsule-from-patients-with-frozen-shoulder
#11
Yoshihiro Hagiwara, Masaru Mori, Kenji Kanazawa, Akira Ando, Yutaka Yabe, Masashi Koide, Takuya Sekiguchi, Nobuyuki Itaya, Masahiro Tsuchiya, Eiji Itoi
BACKGROUND: The etiology of frozen shoulder (FS) is unclear. Accordingly, this study used a label-free quantitative shotgun proteomic approach to elucidate the pathogenesis of FS based on protein expression levels. METHODS: Tissue samples from the rotator interval (RI), middle glenohumeral ligament (MGHL), and anterior-inferior glenohumeral ligament (IGHL) were collected from 12 FSs with severe stiffness and 7 shoulders with a rotator cuff tear (RCT) as controls...
May 18, 2018: Journal of Shoulder and Elbow Surgery
https://www.readbyqxmd.com/read/29784404/evaluation-of-a-flow-through-dialysis-probe-for-sampling-and-sample-preparation-hyphenation-to-ion-chromatography
#12
Inga Markeviciute, Wolfgang Frenzel
A commercially available dialysis probe has, for the first time, been evaluated for sampling and sample preparation in combination with ion chromatography (IC). In operation the probe is immersed into the sample solution and a receiver liquid is propelled through the probe behind a suitable dialysis membrane. Small inorganic anions (fluoride, chloride, nitrite, bromide, nitrate, sulfate, phosphate) are transferred across the membrane into the receiver liquid and carried towards the injection valve of the IC system...
August 15, 2018: Talanta
https://www.readbyqxmd.com/read/29784372/fast-and-reliable-bia-amperometric-quantification-of-acetylcysteine-using-a-nanostructured-double-hydroxide-sensor
#13
Anabel Laza Correa, Josué M Gonçalves, Pamela O Rossini, Juliana S Bernardes, Carlos A Neves, Koiti Araki, Lucio Angnes
This study reports the preparation and characterization of nickel/lead hydroxide nanoparticles used to construct electrochemical sensors, which were investigated for amperometric quantification of N-acetylcysteine (NAC). The newly synthesised material presents good uniformity, with the lead (II) ions homogenously incorporated into the alpha nickel hydroxide crystal structure, confirmed by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy analyses. Films of nanoparticles (3 nm in size) were prepared on conductive fluorine-doped tin oxide-coated glass slides and used connected to a specially built batch injection analysis (BIA) cell with a capacity of only 4 mL and the electrode positioned in the bottom...
August 15, 2018: Talanta
https://www.readbyqxmd.com/read/29782982/process-optimization-purification-and-characterization-of-a-novel-acidic-thermostable-chitinase-from-humicola-grisea
#14
Manish Kumar, Amandeep Brar, V Vivekanand, Nidhi Pareek
An extracellular acidic and thermostable chitinase (HgChi) from thermophilic Humicola grisea was purified and characterized. Enhancement in chitinase production (Qp  = 2.9662 Ul-1  h-1 ) was achieved through derivation of optimum fermentation conditions via central composite design. H. grisea observed to produce various isoforms of chitinase, among which the major expressed form has molecular mass of about 50 kDa. Purified chitinases exhibited optimal activity at pH 3.0 and 70 °C. Chitinase showed notable stability at increasing temperatures...
May 18, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29782002/quantitative-and-qualitative-method-for-sphingomyelin-by-lc-ms-using-two-stable-isotopically-labeled-sphingomyelin-species
#15
Kotaro Hama, Yuko Fujiwara, Kazuaki Yokoyama
We present a method of analyzing sphingomyelin (SM) qualitatively and quantitatively by liquid chromatography-electrospray Ionization-tandem mass spectrometry (LC-ESI-MS/MS). SM is a common sphingolipid composed of a phosphorylcholine and a ceramide as the hydrophilic and hydrophobic component, respectively. A number of SM species are present in mammalian cells due to a variety in the sphingoid long chain base (LCB) and an N-acyl moiety in the ceramide. In this report, we show a method of estimating the number of carbon and double bonds in a LCB and an N-acyl moiety based on their corresponding product ions in MS/MS/MS (MS3 ) experiments...
May 7, 2018: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/29781236/detection-of-acetyltransferase-modification-of-kanamycin-an-aminoglycoside-antibiotic-in-bacteria-using-ultra-high-performance-liquid-chromatography-tandem-mass-spectrometry
#16
Johnny J Perez, Chin-Yi Chen
RATIONALE: The occurrence of antibiotic resistant (AR) bacteria is a worldwide issue that has the potential, if not addressed, to eliminate classes of antibiotics that have extended life expectancy in the last century. An approach to confront this threat is the development of technologies that greatly accelerate the detection of AR to minimize unnecessary treatment involving antibiotics. Development of an analytical method for rapid detection of aminoglycoside resistance using liquid chromatography mass spectrometry (LC-MS) has not been reported in literature and is described here...
May 20, 2018: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/29778875/purification-of-recombinant-trichodysplasia-spinulosa-associated-polyomavirus-vp1-derived-virus-like-particles-using-chromatographic-techniques
#17
Mindaugas Zaveckas, Karolis Goda, Danguole Ziogiene, Alma Gedvilaite
Trichodysplasia spinulosa-associated polyomavirus (TSPyV) has been linked to a rare and recently characterized skin disease occurring in immunocompromised patients. In analogy with other polyomaviruses, the major capsid protein VP1 of TSPyV can self-assemble into virus-like particles (VLPs). VLPs are increasingly applied for the vaccination and diagnostics. Mostly, non-scalable and labor intensive ultracentrifugation-based techniques are used for the purification of VLPs. In this work, we developed a purification procedure for TSPyV VP1 VLPs based on two chromatographic steps, ion-exchange monolith and core bead chromatography...
May 9, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/29777809/systematic-fractionation-and-immunoenhancement-of-water-soluble-polysaccharides-isolated-from-fruit-of-morus-alba-l
#18
DongXue Wang, Hui Li, Bo Li, Rui Ma, Ning Zhang, Xiaoyu Zhang, Lili Jiao, Wei Wu
In this study, we obtained and fractionated systematically the polysaccharides of Fructus mori fruit by the sequential use of water extraction, ethanol precipitation and ion-exchange chromatography. The sugar contents of FPA-1, FPA-2, FPA-4 and FPA-5 were estimated to be 75.70%, 67.15%, 87.78% and 91.63%, respectively. Monosaccharide composition analysis revealed that all the polysaccharides primarily contained Man, GlcA, GalA, Glc, Gal, Xyl, Ara and Fuc. Moreover, a small amount of Rha was detected in FPA-1, FPA-4 and FPA-5...
May 16, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29776673/the-influence-of-addition-of-ion-pairing-acid-and-organic-modifier-of-the-mobile-phase-on-retention-and-migration-of-peptides-in-pressurized-planar-electrochromatography-system-with-octadecyl-silica-based-adsorbent
#19
Radosław Ł Gwarda, Tadeusz H Dzido
In our previous papers we have investigated the influence of the mobile phase composition on mechanism of retention, selectivity and efficiency of peptide separation in various high-performance thin-layer chromatography (HPTLC) systems with commercially available silica-based adsorbents. We have also investigated the influence of pH of the mobile phase buffer on migration and separation of peptides in pressurized planar electrochromatography (PPEC). Here we investigate the influence of concentration of ion-pairing additive, and concentration and type of organic modifier of the mobile phase on migration of peptides in PPEC system with octadecyl silica-based adsorbent, and with the same set of the solutes as before...
May 15, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29773388/a-unique-polysaccharide-containing-3-o-methylarabinose-and-3-o-methylgalactose-from-tinospora-sinensis
#20
Shipra Nagar, Andreas Hensel, Petra Mischnick, Vineet Kumar
Tinospora sinensis (Lour.) Merrill is of great therapeutic significance in Indian traditional medicine. Crude polysaccharides were isolated from methanol pre-extracted stems of dried material by successive extractions with cold water, hot water and NaOH (0.25 mol/L) in 0.98, 0.55 and 0.70 % yields respectively. Cold water soluble polysaccharides (CWSP) were purified and fractionated by ion exchange chromatography on DEAE-Sephacel. Neutral polysaccharides were further fractionated on Sepharose CL6B to yield three fractions TW1, TW2, TW3...
August 1, 2018: Carbohydrate Polymers
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