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https://www.readbyqxmd.com/read/28109808/selective-adsorption-of-pb-ii-ions-by-amylopectin-g-poly-acrylamide-co-acrylic-acid-a-bio-degradable-graft-copolymer
#1
Dinabandhu Sasmal, Jayanta Maity, Haradhan Kolya, Tridib Tripathy
Amylopectin-g-poly (acrylamide-co-acrylic acid) [AP-g-poly (AM-co-AA)] was synthesised in water medium by using potassium perdisulphate as an initiator. The graft copolymer was characterized by molecular weight determination by size exclusion chromatography (SEC), fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscope (SEM) studies, thermal analysis, measurement of neutralisation equivalent and biodegradation studies. The graft copolymer was used for Pb (II) ion removal from aqueous solution...
January 18, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28108753/release-of-free-amino-acids-upon-oxidation-of-peptides-and-proteins-by-hydroxyl-radicals
#2
Fobang Liu, Senchao Lai, Haijie Tong, Pascale S J Lakey, Manabu Shiraiwa, Michael G Weller, Ulrich Pöschl, Christopher J Kampf
Hydroxyl radical-induced oxidation of proteins and peptides can lead to the cleavage of the peptide, leading to a release of fragments. Here, we used high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and pre-column online ortho-phthalaldehyde (OPA) derivatization-based amino acid analysis by HPLC with diode array detection and fluorescence detection to identify and quantify free amino acids released upon oxidation of proteins and peptides by hydroxyl radicals. Bovine serum albumin (BSA), ovalbumin (OVA) as model proteins, and synthetic tripeptides (comprised of varying compositions of the amino acids Gly, Ala, Ser, and Met) were used for reactions with hydroxyl radicals, which were generated by the Fenton reaction of iron ions and hydrogen peroxide...
January 20, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28107975/comparison-of-sample-preparation-strategies-for-target-analysis-of-total-thyroid-hormones-levels-in-serum-by-liquid-chromatography-quadrupole-time-of-flight-mass-spectrometry
#3
E Álvarez, Y Madrid, M D Marazuela
This paper describes a novel method based on liquid chromatography quadrupole time-of-flight-mass spectrometry (LC-QTOF-MS) for target analysis of total THs in serum. Several sample preparation strategies have been evaluated to reduce matrix effect (namely, HybridSPE cartridges, supported liquid extraction, SLE and solid phase extraction, SPE). Deproteinization and further clean-up with mixed-mode SPE was selected as the best strategy for sample preparation, since achieved the cleanest extracts and reduced ionization suppression effects (between -11 and -24%)...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107923/a-sensitive-and-rapid-uflc-apci-ms-ms-bioanalytical-method-for-quantification-of-endogenous-and-exogenous-vitamin-k1-isomers-in-human-plasma-development-validation-and-first-application-to-a-pharmacokinetic-study
#4
Nagaraj Kumar Nannapaneni, Sunil S Jalalpure, Rajendraprasad Muppavarapu, Sunil Kumar Sirigiri
Due to lack of suitable bioanalytical methods in previous literature, for simultaneous estimation of Vitamin K1 isomers, in compliance with the current regulatory expectation, we aimed to develop a sensitive and rapid method with UFLC-APCI-MS/MS (ultrafast liquid chromatography - tandem mass spectrometry) using human plasma. A simple and cost effective procedure was implemented with the combination of protein precipitation and liquid extraction, to isolate the targets from plasma sample, while achieving an insignificant matrix effects and high recovery (≥88...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107921/highly-selective-enrichment-of-phosphopeptides-using-zr-4-immobilized-titania-nanoparticles
#5
Junyong Dai, Miaode Wang, Hailong Liu
It is urgent to selectively enrich trace phosphorylated proteins or peptides from complex biological sample for mass spectrometry (MS)-based phosphoproteomics. In this study, a novel immobilized metal affinity chromatography (IMAC) material with DOTA(1,4,7,10-tetraazacyclododecane N, N', N'', N'''-tetra-acetic acid) coated on the surface of TiO2 nanomaterials and functionalized with the metal ion Zr(4+)(TiO2@DOTA-Zr) has been synthesized successfully to improve the enrichment specificity and sensitivity for phosphopeptides...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107906/development-of-data-independent-acquisition-workflows-for-metabolomic-analysis-on-a-quadrupole-orbitrap-platform
#6
Juntuo Zhou, Yuhua Li, Xi Chen, Lijun Zhong, Yuxin Yin
Untargeted metabolomic profiling has been widely used in recent years. However, the low reproducibility of the data-dependent acquisition (DDA) strategy presents a major bottleneck that considerably limits the reliability of metabolomic studies in biological and clinical research. The data-independent acquisition (DIA) strategy is proposed to solve the above-mentioned problem, and it is gaining popularity. This paper presents a novel approach for performing metabolomic analysis using an untargeted, liquid chromatography-data independent-mass spectrometry (LC-DIA-MS) strategy on a quadrupole-Orbitrap platform...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107903/ion-mobility-spectrometry-as-a-fast-analytical-tool-in-benzalkonium-chloride-homologs-determination
#7
D Gallart-Mateu, S Armenta, F A Esteve-Turrillas, M de la Guardia
A novel procedure is proposed for the determination by ion mobility spectrometry (IMS) of C12, C14 and C16 benzalkonium chloride (BAC) homologs. The proposed method requires minimum sample treatment and the measurement was made in less than one minute. A high sensitivity was obtained for BAC determination by IMS with limit of detection values from 37 to 69µgL(-1). Accuracy of the proposed methodology was evaluated through the analysis of aqueous and alcoholic samples spiked with BAC at concentration levels from 0...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28106083/the-association-of-bacterial-c9-based-ttx-like-compounds-with-prorocentrum-minimum-opens-new-uncertainties-about-shellfish-seafood-safety
#8
Inés Rodríguez, Amparo Alfonso, Eva Alonso, Juan A Rubiolo, María Roel, Aristidis Vlamis, Panagiota Katikou, Stephen A Jackson, Margassery Lekha Menon, Alan Dobson, Luis M Botana
In 2012, Tetrodotoxin (TTX) was identified in mussels and linked to the presence of Prorocentrum minimum (P. minimum) in Greece. The connexion between TTX and P. minimum was further studied in this paper. First, the presence of TTX-producer bacteria, Vibrio and Pseudomonas spp, was confirmed in Greek mussels. In addition these samples showed high activity as inhibitors of sodium currents (INa). P. minimum was before associated with neurotoxic symptoms, however, the nature and structure of toxins produced by this dinoflagellate remains unknown...
January 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28104235/determination-and-quantification-of-cations-in-ionic-liquids-by-capillary-electrophoresis-mass-spectrometry
#9
Marcelina Pyschik, Martin Winter, Sascha Nowak
In this study, a capillary electrophoresis (CE) method hyphenated to a high-resolution mass spectrometer is presented to detect the cations in ionic liquids (ILs) and their decomposition products. The investigated ILs were 1-methyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR13TFSI), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIM TFSI). With this method, it was possible to achieve baseline separation of the decomposition products from the main cations in short migration times...
January 13, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28102926/sodiation-based-in-source-collision-for-profiling-of-pyranocoumarins-in-radix-peucedani-qianhu-utility-of-sodium-adducts-stability-with-in-source-collision
#10
Wei Yang, Yingfei Li, Chen Kang, Haiyu Zhao, Li Xiang, Chuan Li, Qiao Wang
Full scan mode of liquid chromatography-mass spectrometry equipped with an electrospray ionization source offers a chance on global detection of complicated components; however, the scan mode carries significant challenges in rapidly capturing information of analysts. Sodiation-based in-source collision was proposed here, as a technique for rapid detecting untargeted analytes in full scan analysis, which was based on the stability of sodium adducts and the nonselectivity of in-source collision. Then the technique was applied to profile of angular-type pyranocoumarins (APs) in Radix Peucedani, with full scan analysis performed at two specific in-source collision energy: a high energy 50 V that is tolerated by the sodium adducts of APs, and a low energy 10 V, at which abundant adducts were offered...
January 19, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28102738/optimization-and-partial-characterization-of-intracellular-anticandidal-protein-from-aspergillus-giganteus-mtcc-8408-using-taguchi-doe
#11
Debashis Dutta, Mira Debnath Das
A new intracellular antifungal protein (afp) production with average molecular weight 24.3 kDa and yield of 0.65 ± 0.1 mg/gram dry cell weight (gdcw) of mycelia in submerged fermentation of Aspergillus giganteus MTCC 8408 was optimized. Taguchi's DOE (design of experiment) L27 orthogonal array (OA) was constructed using Qualitek-4 software with 8 most influensive factors namely, culture pH, temperature, slant age, inoculum volume, agitation and KH2PO4. Scanning electron microscopy (SEM) was used to correlate the effect of selected factors on fungal cell morphology and afp production...
January 19, 2017: Bioengineered
https://www.readbyqxmd.com/read/28101932/amino-acid-profiling-of-zinc-resistant-prostate-cancer-cell-lines-associations-with-cancer-progression
#12
Monika Kratochvilova, Martina Raudenska, Zbynek Heger, Lukas Richtera, Natalia Cernei, Vojtech Adam, Petr Babula, Marie Novakova, Michal Masarik, Jaromir Gumulec
BACKGROUND: Failure in intracellular zinc accumulation is a key process in prostate carcinogenesis. Nevertheless, epidemiological studies of zinc administration have provided contradicting results. In order to examine the impact of the artificial intracellular increase of zinc(II) ions on prostate cancer metabolism, PNT1A, 22Rv1, and PC-3 prostatic cell lines-depicting different stages of cancer progression-and their zinc-resistant counterparts were used. To determine "benign" and "malignant" metabolic profiles, amino acid patterns, gene expression, and antioxidant capacity of these cell lines were assessed...
January 19, 2017: Prostate
https://www.readbyqxmd.com/read/28101806/purification-and-characterization-of-glutamate-decarboxylase-from-enterococcus-raffinosus-tccc11660
#13
Chuanyou Chang, Jun Zhang, Shenxi Ma, Lin Wang, Depei Wang, Jian Zhang, Qiang Gao
Glutamate decarboxylase (GAD) is the sole enzyme that synthesizes γ-aminobutyric acid through the irreversible decarboxylation of L-glutamate. In this study, the purification and characterization of an unreported GAD from a novel strain of Enterococcus raffinosus TCCC11660 were investigated. The native GAD from E. raffinosus TCCC11660 was purified 32.3-fold with a recovery rate of 8.3%, using ultrafiltration and ammonium sulfate precipitation, followed by ion-exchange and size-exclusion chromatography. The apparent molecular weight of purified GAD, as determined by SDS-PAGE and size-exclusion chromatography was 55 and 110 kDa, respectively, suggesting that GAD exists as a dimer of identical subunits in solution...
January 18, 2017: Journal of Industrial Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28100125/sulphur-dioxide-in-meat-products-3-years-control-results-of-an-accredited-italian-laboratory
#14
Marco Iammarino, Anna Rita Ientile, Aurelia Di Taranto
Sulphiting agents are well-known food preservatives. The European legislation does not allow their addition in fresh meat preparations. Therefore this type of food products has often been verified. To high sulphite levels in food is a health safety risk, due to toxic effects that these compounds may exercise on humans. In this study the control activity as performed by an Italian accredited laboratory from 2013 to 2015, relating to determination of sulphites in meat products, is described. Six hundred and sixty-nine meat product samples were analysed...
January 19, 2017: Food Additives & Contaminants. Part B, Surveillance
https://www.readbyqxmd.com/read/28100074/antioxidant-capacity-and-identification-of-the-constituents-of-ethyl-acetate-fraction-from-rhus-verniciflua-stokes-by-hplc-ms
#15
Hongxia Chen, Chengzhang Wang, Hao Zhou, Ran Tao, Jianzhong Ye, Wenjun Li
Ethyl acetate fraction (EAF) from Rhus verniciflua Stokes is an important source of bioactive compounds. The aim of this study was the tentative identification and quantification of phenolic compounds, comparison of the phenolic structure-antioxidant activity relationships. Twelve compounds of EAF belonging to polyphenol types were detected by high performance liquid chromatography and analysed on line with negative ion electrospray ionisation tandem mass spectrometry, which were ethoxy 3-hydroxy benzoic acid, gallic acid (GA), 3,4-dihydroxy amygdalic acid, gallic acid cetyl ester, protocatechuic acid (PA), fustin, ethyl gallate (EG), garbanzol, fisetin, sulfuretin, butin and 3,7-dihydroxyflavanone-4'-rhamnoside...
January 18, 2017: Natural Product Research
https://www.readbyqxmd.com/read/28098420/deciphering-chemical-interactions-between-glycyrrhizae-radix-and-coptidis-rhizoma-by-liquid-chromatography-with-transformed-multiple-reaction-monitoring-mass-spectrometry
#16
Zhenhao Li, Ting Liu, Jie Liao, Ni Ai, Xiaohui Fan, Yiyu Cheng
In this study, we propose an integrated strategy for the efficient identification and quantification of herbal constituents using liquid chromatography with mass spectrometry. First, liquid chromatography with quadrupole time-of-flight mass spectrometry was employed for the chemical profiling of herbs, where a targeted following non-targeted approach was developed to detect trace constituents by using structural correlations and extracted ion chromatograms. Next, ion pairs and parameters of MS(2) of quadrupole time-of-flight mass spectrometry were selected to design multiple reaction monitoring transitions for the identified compounds on liquid chromatography with triple quadrupole mass spectrometry...
January 18, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28098337/characterisation-of-the-enzymatic-properties-of-mpapr1-an-aspartic-protease-secreted-by-the-wine-yeast-metschnikowia-pulcherrima
#17
Louwrens Wiid Theron, Marina Bely, Benoit Divol
BACKGROUND: MpAPr1, encoding an acid protease from the wine yeast Metschnikowia pulcherrima IWBT Y1123, was previously isolated and shown to display potential activity against casein and grape proteins. However, its characterisation remained partial. RESULTS: MpAPr1 was cloned into the pGAPZαA vector and transformed into Komagataella pastoris X33 for heterologous expression. After verification of activity, the enzyme properties were characterised. Protease activity within the concentrated supernatant was retained over a pH range of 3...
January 18, 2017: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/28098263/a-lab-on-a-chip-for-monolith-based-preconcentration-and-electrophoresis-separation-of-phosphopeptides
#18
Monica Araya-Farias, Szymon Dziomba, Benjamin Carbonnier, Mohamed Guerrouache, Ichraf Ayed, Nacera Aboud, Myriam Taverna, N Thuy Tran
A microdevice combining online preconcentration and separation of phosphopeptides was developed in a glass microchip. An ethylene glycol methacrylate phosphate (EGMP), acrylamide (AM) and bisacrylamide (BAA) based monolith was synthesized within microchannels through a photo-driven process. Morphological investigations revealed a homogeneous monolithic structure composed of uniform nodules (∼0.8 μm), with a large pore volume (0.62 cm(3) g(-1)) and sufficiently high specific surface area (34.1 m(2) g(-1))...
January 18, 2017: Analyst
https://www.readbyqxmd.com/read/28097886/reagent-free-lc-ms-ms-based-pharmacokinetic-quantification-of-polyhistidine-tagged-therapeutic-proteins
#19
Jianxia Shi, Jing Man Wong, Ji Ma, Tiffany Dickerson, Colin Hall, Dan A Rock, Timothy J Carlson
AIM: Immobilized metal ion affinity chromatography is widely employed for purifying polyhistidine-tagged recombinant proteins from cell lysates. The technique can be applied for quantification of therapeutic proteins in biological matrices by LC-MS/MS. RESULTS: A protein reagent-free workflow was developed for quantifying polyhistidine-tagged proteins by LC-MS/MS. The workflow includes target protein enrichment by immobilized metal ion affinity chromatography, on-bead trypsin digestion and quantification of signature peptides by LC-MS/MS...
January 18, 2017: Bioanalysis
https://www.readbyqxmd.com/read/28097168/purification-and-biochemical-properties-of-a-thermostable-haloalkaline-cellulase-from-bacillus-licheniformis-amf-07-and-its-application-for-hydrolysis-of-different-cellulosic-substrates-to-bioethanol-production
#20
Fatemeh Azadian, Arastoo Badoei-Dalfard, Abdolhamid Namaki-Shoushtari, Mehdi Hassanshahian
A thermophilic strain AMF-07, hydrolyzing carboxymethylcellulose (CMC) was isolated from Kerman hot spring and was identified as Bacillus licheniformis based on 16S rRNA sequence homology. The carboxymethylcellulase (CMCase) enzyme produced by the B. licheniformis was purified by (NH4)2SO4 precipitation, ion exchange and gel filtration chromatography. The purified enzyme gave a single band on SDS- PAGE with a molecular weight of 37 kDa. The CMCase enzyme was highly active and stable over broad ranges of temperature (40-80ºC), pH (6...
September 2016: Molecular Biology Research Communications
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