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https://www.readbyqxmd.com/read/29150927/identification-of-proteins-drying-oils-waxes-and-resins-in-the-works-of-art-micro-samples-by-chromatographic-and-mass-spectrometric-techniques
#1
Bartłomiej Witkowski, Anna Duchnowicz, Monika Ganeczko, Agnieszka Laudy, Tomasz Gierczak, Magdalena Biesaga
Simplified method for simultaneous identification of proteins, drying oils, waxes and resins in the works-of-art samples was developed. Liquid chromatography with mass spectrometry and gas chromatography with mass spectrometry were used to identify natural materials most frequently encountered in historical paintings. Protein binders were extracted with ammonia and purified using miniaturized solid-phase microextraction (Omix tips) to efficiently suppress matrix interferences. Zwitterionic stationary phase was used for separation of sixteen underivatized amino acids analysis with hydrophilic interaction liquid chromatography that were subsequently quantified with liquid chromatography with mass spectrometry...
November 18, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/29150857/a-randomized-double-blind-placebo-controlled-dose-finding-trial-with-lolium-perenne-peptide-immunotherapy
#2
Ralph Mösges, Elena M Kasche, Esther Raskopf, Jaswinder Singh, Lea Sohlich, Anatoli Astvatsatourov, Kija Shah-Hosseini, Sabine Pirotton, Ludo Haazen, Stephen R Durham, Thierry Legon, Gregor Zadoyan, Mohamed H Shamji
BACKGROUND: A novel subcutaneous allergen immunotherapy formulation (gpASIT+(™) ) containing Lolium perenne peptides (LPP) and having a short up-dosing phase has been developed to treat grass pollen-induced seasonal allergic rhinoconjunctivitis. We investigated peptide immunotherapy containing the hydrolysate from perennial ryegrass allergens for the optimum dose in terms of clinical efficacy, immunogenicity, and safety. METHODS: This prospective, double-blind, placebo-controlled, phase IIb, parallel, four-arm, dose-finding study randomized 198 grass pollen-allergic adults to receive placebo or cumulative doses of 70, 170, or 370 μg LPP...
November 18, 2017: Allergy
https://www.readbyqxmd.com/read/29150709/simultaneous-detection-of-nadph-consumption-and-h2o2-production-using-the-ampliflu%C3%A2-red-assay-for-screening-of-p450-activities-and-uncoupling
#3
Lisa K Morlock, Dominique Böttcher, Uwe T Bornscheuer
Cytochrome P450s belong to a large and diverse group of heme-containing enzymes. These monooxygenases catalyze the incorporation of a single atom of molecular oxygen into their substrate. In contrast to most other enzymes, the activity of P450 enzymes is not only dependent on substrate and cofactor availability and reaction conditions, but also depends on the coupling efficiency of the catalytic cycle itself. Through the electron transfer from NAD(P)H to the heme-center of the P450, the enzyme becomes activated and binds oxygen...
November 17, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/29149566/iedda-reaction-of-molecular-iodine-catalyzed-synthesis-of-1-3-5-triazines-via-functionalization-of-sp-3-c-h-bond-of-acetophenones-with-amidines-an-experimental-investigation-and-dft-study
#4
Abhishek Rajesh Tiwari, Shilpa Raveendra Nath, Kaustubh Ashok Joshi, Bhalchandra Mahadeo Bhanage
The present work reports an inverse electron demand Diels Alder (iEDDA) type reaction to synthesize 1,3,5-trizines from acetophenones and amidines. The use of molecular iodine in catalytic amount facilitates the functionalization of sp3 C-H bond of acetophenones. This is a simple and efficient methodology for the synthesis of 1,3,5-triazines in good to excellent yields under transition metal-free and peroxide-free conditions. The reaction is believed to take place via an in situ iodination-based oxidative elimination of formaldehyde...
November 17, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29148746/keto-enol-tautomerization-triggers-an-electrophilic-aldehyde-deformylation-reaction-by-a-nonheme-manganese-iii-peroxo-complex
#5
Fabián G Cantú Reinhard, Prasenjit Barman, Gourab Mukherjee, Jitendra Kumar, Deep Kumar, Devesh Kumar, Chivukula V Sastri, Sam P de Visser
Oxygen atom transfer by high-valent enzymatic intermediates remains an enigma in chemical catalysis. In particular, manganese is an important first-row metal involved in key biochemical processes including the biosynthesis of mo-lecular oxygen (through the photosystem II complex) and biodegradation of toxic superoxide to hydrogen peroxide by superoxide dismutase. Biomimetic models of these biological systems have been developed to gain understanding on the structure and properties of short-lived intermediates but also with the aim to create environmentally benign oxidants...
November 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29147904/the-multifaceted-roles-of-dj-1-as-an-antioxidant
#6
Prahlad V Raninga, Giovanna Di Trapani, Kathryn F Tonissen
The DJ-1 protein was originally linked with Parkinson's disease and is now known to have antioxidant functions. The protein has three redox-sensitive cysteine residues, which are involved in its dimerisation and functional properties. A mildly oxidised form of DJ-1 is the most active form and protects cells from oxidative stress conditions. DJ-1 functions as an antioxidant through a variety of mechanisms, including a weak direct antioxidant activity by scavenging reactive oxygen species. DJ-1 also regulates a number of signalling pathways, including the inhibition of apoptosis signal-regulating kinase 1 (ASK1)-induced apoptosis under oxidative stress conditions...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/29147812/geissoschizine-synthase-controls-flux-in-the-formation-of-monoterpenoid-indole-alkaloids-in-a-catharanthus-roseus-mutant
#7
Yang Qu, Antje M K Thamm, Matthew Czerwinski, Sayaka Masada, Kyung Hee Kim, Graham Jones, Ping Liang, Vincenzo De Luca
A Catharanthus roseus mutant accumulates high levels of ajmalicine at the expense of catharanthine and vindoline. The altered chemistry depends on increased expression and biochemical activities of strictosidine β-glucosidase and ajmalicine synthase activities and reduced expression and biochemical activity of geissoschizine synthase. The Madagascar periwinkle [Catharanthus roseus (L.) G. Don] is a commercially important horticultural flower species and is a valuable source for several monoterpenoid indole alkaloids (MIAs), such as the powerful antihypertensive drug ajmalicine and the antineoplastic agents, vinblastine and vincristine...
November 17, 2017: Planta
https://www.readbyqxmd.com/read/29144749/synthesis-and-reactivity-of-a-low-coordinate-iron-ii-hydride-complex-applications-in-catalytic-hydrodefluorination
#8
Nicholas M Hein, Fraser S Pick, Michael D Fryzuk
A low-coordinate iron hydride complex bearing an unsymmetrical NpN (enamido-phosphinimine) ligand scaffold was synthesized and fully characterized. Insertion reactivity with azobenzene, 3-hexyne, and 1-azidoadamantane was explored, and the isolated products were analogous to previously reported β-diketiminate iron hydride insertion products. Surprisingly, the NpN iron hydride displays unprecedented reactivity toward hexafluorobenzene, affording an NpN iron fluoride complex and pentafluorobenzene as products...
November 16, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/29144013/photocontrolled-synthesis-of-abiotic-sequence-defined-oligo-phosphodiester-s
#9
Niklas Felix König, Sofia Telitel, Salomé Poyer, Laurence Charles, Jean-François Lutz
A photoregulated phosphoramidite iterative process is studied for the synthesis of non-natural, digitally encoded oligo(phosphodiester)s. The oligomers are prepared using two reactive phosphoramidite monomers containing a 2-(2-nitrophenyl)propoxycarbonyl (NPPOC) protected OH group. The stepwise synthesis is performed on an OH-functional soluble polystyrene support, which allows recycling by precipitation in a nonsolvent. Repeating cycles involving phosphoramidite coupling, oxidation of phosphite to phosphate, and NPPOC deprotection by light irradiation at λ = 365 nm are performed in order to prepare oligomers with different lengths and sequences...
November 16, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/29136068/electrokinetically-operated-microfluidic-devices-for-integrated-immunoaffinity-monolith-extraction-and-electrophoretic-separation-of-preterm-birth-biomarkers
#10
Mukul Sonker, Ellen K Parker, Anna V Nielsen, Vishal Sahore, Adam T Woolley
Biomarkers are often present in complex biological fluids like blood, requiring multiple, slow sample preparation steps that pose limitations in simplifying analysis. Here we report integrated immunoaffinity extraction and separation devices for analysis of preterm birth biomarkers in a human blood serum matrix. A reactive polymer monolith was used for immobilization of antibodies for selective extraction of target preterm birth biomarkers. Microfluidic immunoaffinity extraction protocols were optimized and then integrated with microchip electrophoresis for separation...
November 14, 2017: Analyst
https://www.readbyqxmd.com/read/29132391/nadph-oxidases-in-parkinson-s-disease-a-systematic-review
#11
REVIEW
Karim Belarbi, Elodie Cuvelier, Alain Destée, Bernard Gressier, Marie-Christine Chartier-Harlin
Parkinson's disease (PD) is a progressive movement neurodegenerative disease associated with a loss of dopaminergic neurons in the substantia nigra of the brain. Oxidative stress, a condition that occurs due to imbalance in oxidant and antioxidant status, is thought to play an important role in dopaminergic neurotoxicity. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases are multi-subunit enzymatic complexes that generate reactive oxygen species as their primary function. Increased immunoreactivities for the NADPH oxidases catalytic subunits Nox1, Nox2 and Nox4 have been reported in the brain of PD patients...
November 13, 2017: Molecular Neurodegeneration
https://www.readbyqxmd.com/read/29131622/computational-study-of-engineered-cytochrome-p450-catalyzed-c-h-amination-the-origin-of-the-regio-and-stereoselectivity
#12
Zhe Li, D Jean Burnell, Russell Jaye Boyd
Cytochrome P450 enzymes were recently engineered to catalyze the C-H amination reaction of aryl sulfonyl azides with excellent regio- and stereoselectivity (Arnold and coworkers JACS, 2014, 136, 15505). The mechanism of this reaction was studied by quantum mechanical (QM)/molecular mechanical (MM) calculations in this work. The C-H activation is found to be a stepwise process consisting of hydrogen abstraction (H-abstraction) of the reactive C-H bond by an iron nitrenoid cofactor to produce the biradical intermediate and the subsequent radical rebinding to form the final product...
November 13, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29130684/influence-of-proton-acceptors-on-the-proton-coupled-electron-transfer-reaction-kinetics-of-a-ruthenium-tyrosine-complex
#13
J Christian Lennox, Jillian L Dempsey
A polypyridyl ruthenium complex with fluorinated bipyridine ligands and a covalently bound tyrosine moiety was synthesized, and its photo-induced proton-coupled electron transfer (PCET) reactivity in acetonitrile was investigated with transient absorption spectroscopy. Using flash-quench methodology with methyl viologen as an oxidative quencher, a Ru(3+) species is generated that is capable of initiating the intramolecular PCET oxidation of the tyrosine moiety. Using a series of substituted pyridine bases, the reaction kinetics were found to vary as a function of proton acceptor concentration and identity, with no significant H/D kinetic isotope effect...
November 13, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29128754/development-and-characterization-of-a-human-monoclonal-antibody-targeting-the-n-terminal-region-of-hepatitis-c-virus-envelope-glycoprotein-e1
#14
Ahmed Atef Mesalam, Isabelle Desombere, Ali Farhoudi, Freya Van Houtte, Lieven Verhoye, Jonathan Ball, Jean Dubuisson, Steven K H Foung, Arvind H Patel, Mats A A Persson, Geert Leroux-Roels, Philip Meuleman
Monoclonal antibodies (mAbs) targeting the hepatitis C virus (HCV) envelope have been raised mainly against envelope protein 2 (E2), while the antigenic epitopes of envelope protein 1 (E1) are not fully identified. Here we describe the detailed characterization of a human mAb, designated A6, generated from an HCV genotype 1b infected patient. ELISA results showed reactivity of mAb A6 to full-length HCV E1E2 of genotypes 1a, 1b and 2a. Epitope mapping identified a region spanning amino acids 230-239 within the N-terminal region of E1 as critical for binding...
November 9, 2017: Virology
https://www.readbyqxmd.com/read/29128091/non-protease-native-allergens-partially-purified-from-bodies-of-eight-domestic-mites-using-p-aminobenzamidine-ligand
#15
T Erban, R Klubal
BACKGROUND: Optimised purification steps for concentrating trace target native antigens are needed. Combining the p-aminobenzamidine ligand with protease inactivation enables partial purification of mite non-protease allergens lacking proteases. OBJECTIVE: We sought to analyse in detail proteins obtained using this method from eight species of synanthropic acaridid mites and tested IgE reactivity using pooled human sera. MATERIALS AND METHODS: Proteins affinity bound to p-aminobenzamidine as a ligand were identified by MALDI TOF/TOF...
November 8, 2017: Allergologia et Immunopathologia
https://www.readbyqxmd.com/read/29126915/steps-moderate-to-vigorous-physical-activity-and-cardiometabolic-profiles
#16
Samantha Hajna, Nancy A Ross, Kaberi Dasgupta
The relative benefits of meeting the current moderate-to-vigorous intensity physical activity (MVPA) and 'active' step count recommendations are unknown. Using robust linear regressions, we compared cardiometabolic marker differences (blood pressure, lipid levels, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), hemoglobin A1C, C-reactive protein (CRP), and body mass index (BMI)) across MVPA (150min/week) and step (10,000 steps/day) thresholds and between step categories (low active: 5000 to 7499, somewhat active: 7500 to 9999, and active: ≥10,000 steps/day vs...
November 7, 2017: Preventive Medicine
https://www.readbyqxmd.com/read/29126097/cue-induced-craving-among-inhalant-users-development-and-preliminary-validation-of-a-visual-cue-paradigm
#17
Shobhit Jain, Anju Dhawan, S Senthil Kumaran, Raman Deep Pattanayak, Raka Jain
INTRODUCTION: Cue-induced craving is known to be associated with a higher risk of relapse, wherein drug-specific cues become conditioned stimuli, eliciting conditioned responses. Cue-reactivity paradigm are important tools to study psychological responses and functional neuroimaging changes. However, till date, there has been no specific study or a validated paradigm for inhalant cue-induced craving research. The study aimed to develop and validate visual cue stimulus for inhalant cue-associated craving...
October 16, 2017: Asian Journal of Psychiatry
https://www.readbyqxmd.com/read/29125534/full-body-locomotion-reconstruction-of-virtual-characters-using-a-single-inertial-measurement-unit
#18
Christos Mousas
This paper presents a method of reconstructing full-body locomotion sequences for virtual characters in real-time, using data from a single inertial measurement unit (IMU). This process can be characterized by its difficulty because of the need to reconstruct a high number of degrees of freedom (DOFs) from a very low number of DOFs. To solve such a complex problem, the presented method is divided into several steps. The user's full-body locomotion and the IMU's data are recorded simultaneously. Then, the data is preprocessed in such a way that would be handled more efficiently...
November 10, 2017: Sensors
https://www.readbyqxmd.com/read/29121491/examination-of-reactive-motor-responses-to-achilles-tendon-vibrations-during-an-inhibitory-stepping-reaction-time-task
#19
Justine Magnard, Christophe Cornu, Gilles Berrut, Thibault Deschamps
Inhibition is known to influence balance, step initiation and gait control. A specific subcomponent of inhibition, the perceptual inhibition process, has been suggested to be specifically involved in the integration of proprioceptive information that is necessary for efficient postural responses. This study aimed to investigate the inhibition requirements of planning and executing a choice step initiation task in young adults following experimental perturbation of proprioceptive information using Achilles tendon vibrations...
November 6, 2017: Human Movement Science
https://www.readbyqxmd.com/read/29121266/stress-inducible-galactinol-synthase-of-chickpea-cagols-implicates-in-heat-and-oxidative-stress-tolerance-through-reducing-stress-induced-excessive-reactive-oxygen-species-accumulation
#20
Prafull Salvi, Nitin Uttam Kamble, Manoj Majee
Raffinose Family Oligosaccharides (RFOs) participates in various aspects of plant physiology and galactinol synthase (GolS, EC 2.4.1.123) catalyzes the key step of RFO biosynthesis. Stress induced accumulation of RFOs particularly galactinol and raffinose has been reported in few plants; however their precise role and mechanistic insight in stress adaptation remain elusive. In present study, we have shown that the GolS activity as well as galactinol and raffinose content are significantly increased in response to various abiotic stresses in chickpea...
November 7, 2017: Plant & Cell Physiology
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