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Nuclear magnetic resonance

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https://www.readbyqxmd.com/read/29351264/identification-of-cyclic-dipeptides-from-escherichia-coli-as-new-antimicrobial-agents-against-ralstonia-solanacearum
#1
Shihao Song, Shuna Fu, Xiuyun Sun, Peng Li, Ji'en Wu, Tingyan Dong, Fei He, Yinyue Deng
Ralstonia solanacearum is a causative agent of bacterial wilt in many important crops throughout the world. How to control bacterial wilt caused by R. solanacearum is a major problem in agriculture. In this study, we aim to isolate the biocontrol agents that have high efficacy in the control of bacterial wilt. Three new bacterial strains with high antimicrobial activity against R. solanacearum GMI1000 were isolated and identified. Our results demonstrated that these bacteria could remarkably inhibit the disease index of host plant infected by R...
January 19, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29351260/fatty-acid-based-microemulsions-to-combat-ophthalmia-neonatorum-caused-by-neisseria-gonorrhoeae-and-staphylococcus-aureus
#2
Ummara Butt, Amr ElShaer, Lori A S Snyder, Ali A Al-Kinani, Adam Le Gresley, Raid G Alany
The bacterial species Neisseria gonorrhoeae (N. gonorrhoeae) and Staphylococcus aureus (S. aureus) are amongst the main microorganisms that cause ophthalmia neonatorum. The current treatment involves the use of various antibiotics such as ciprofloxacin, cephalosporin, ceftriaxone and cefotaxime. However, this treatment strategy is becoming more ineffective due to the antibiotic resistance in N. gonorrhoeae. The current study explores the potential use of fatty acid based microemulsions (ME) to prevent N. gonorrhoeae and S...
January 19, 2018: Nanomaterials
https://www.readbyqxmd.com/read/29350530/structural-variation-and-microrheological-properties-of-a-homogeneous-polysaccharide-from-wheat-germ
#3
Liyuan Yun, Tao Wu, Rui Liu, Kun Li, Min Zhang
A novel water-soluble polysaccharide (WGP) was purified from the crude wheat germ polysaccharide by Sephacryl S-500HRgel filtration. The molecular weight of WGP was determined as 4.89×106 Da and composed of arabinose, xylose, glucose, and galactose, with a molar ratio of 29.3%:42.7%:14.7%:13.3%, respectively. WGP was subjected for structural characterization by methylation analysis and 1D/2D nuclear magnetic resonance. WGP was mainly a backbone consisting of (1→4)-linked--D-Xylp (19.01%), (1→3, 4)-linked--D-Xylp (26...
January 19, 2018: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/29350255/nuclear-magnetic-resonance-and-high-performance-liquid-chromatography-techniques-for-the-characterization-of-bioactive-compounds-from-humulus-lupulus-l-hop
#4
Davide Bertelli, Virginia Brighenti, Lucia Marchetti, Anna Reik, Federica Pellati
Humulus lupulus L. (hop) represents one of the most cultivated crops, it being a key ingredient in the brewing process. Many health-related properties have been described for hop extracts, making this plant gain more interest in the field of pharmaceutical and nutraceutical research. Among the analytical tools available for the phytochemical characterization of plant extracts, quantitative nuclear magnetic resonance (qNMR) represents a new and powerful technique. In this ambit, the present study was aimed at the development of a new, simple, and efficient qNMR method for the metabolite fingerprinting of bioactive compounds in hop cones, taking advantage of the novel ERETIC 2 tool...
January 19, 2018: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/29348430/rotator-side-chains-trigger-cooperative-transition-for-shape-and-function-memory-effect-in-organic-semiconductors
#5
Hyunjoong Chung, Dmytro Dudenko, Fengjiao Zhang, Gabriele D'Avino, Christian Ruzié, Audrey Richard, Guillaume Schweicher, Jérôme Cornil, David Beljonne, Yves Geerts, Ying Diao
Martensitic transition is a solid-state phase transition involving cooperative movement of atoms, mostly studied in metallurgy. The main characteristics are low transition barrier, ultrafast kinetics, and structural reversibility. They are rarely observed in molecular crystals, and hence the origin and mechanism are largely unexplored. Here we report the discovery of martensitic transition in single crystals of two different organic semiconductors. In situ microscopy, single-crystal X-ray diffraction, Raman and nuclear magnetic resonance spectroscopy, and molecular simulations combined indicate that the rotating bulky side chains trigger cooperative transition...
January 18, 2018: Nature Communications
https://www.readbyqxmd.com/read/29348238/phosphoethanolamine-cellulose-a-naturally-produced-chemically-modified-cellulose
#6
Wiriya Thongsomboon, Diego O Serra, Alexandra Possling, Chris Hadjineophytou, Regine Hengge, Lynette Cegelski
Cellulose is a major contributor to the chemical and mechanical properties of plants and assumes structural roles in bacterial communities termed biofilms. We find that Escherichia coli produces chemically modified cellulose that is required for extracellular matrix assembly and biofilm architecture. Solid-state nuclear magnetic resonance spectroscopy of the intact and insoluble material elucidates the zwitterionic phosphoethanolamine modification that had evaded detection by conventional methods. Installation of the phosphoethanolamine group requires BcsG, a proposed phosphoethanolamine transferase, with biofilm-promoting cyclic diguanylate monophosphate input through a BcsE-BcsF-BcsG transmembrane signaling pathway...
January 19, 2018: Science
https://www.readbyqxmd.com/read/29346111/single-scan-high-resolution-2-d-j-resolved-spectroscopy-in-inhomogeneous-magnetic-fields
#7
Kaiyu Wang, Yuqing Huang, Pieter E S Smith, Zhiyong Zhang, Shuhui Cai, Zhong Chen
OBJECTIVE: A method is proposed to obtain high-resolution 2-D -resolved nuclear magnetic resonance (NMR) spectra in inhomogeneous magnetic fields. METHODS: The proposed experiment enables the acquisition of an entire 2-D spectrum in a single scan by utilizing intermolecular double-quantum coherences and the spatial encoding of NMR observables. RESULTS: Chemical shifts, coupling constants, and multiplet patterns are recovered even when field inhomogeneities are severe enough to completely obscure conventional NMR spectra...
February 2018: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/29345988/measuring-entropy-in-molecular-recognition-by-proteins
#8
A Joshua Wand, Kim A Sharp
Molecular recognition by proteins is fundamental to the molecular basis of biology. Dissection of the thermodynamic landscape governing protein-ligand interactions has proven difficult because determination of various entropic contributions is quite challenging. Nuclear magnetic resonance relaxation measurements, theory, and simulations suggest that conformational entropy can be accessed through a dynamical proxy. Here, we review the relationship between measures of fast side-chain motion and the underlying conformational entropy...
January 18, 2018: Annual Review of Biophysics
https://www.readbyqxmd.com/read/29344890/prediction-of-clinical-endpoints-in-breast-cancer-using-nmr-metabolic-profiles
#9
Leslie R Euceda, Tonje H Haukaas, Tone F Bathen, Guro F Giskeødegård
Metabolic profiles reflect biological conditions as a result of biochemical changes within a living system. It is therefore possible to associate metabolic signatures with clinical endpoints of diseases, such as breast cancer. Nuclear magnetic resonance (NMR) spectroscopy is one of the most common techniques used for metabolic profiling, and produces high dimensional datasets from which meaningful biological information can be extracted. Here, we present an overview of data analysis techniques used to achieve this, describing key steps in the procedure...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29344518/current-modalities-for-the-assessment-of-future-remnant-liver-function
#10
REVIEW
Fadi Rassam, Pim B Olthof, Roelof J Bennink, Thomas M van Gulik
While imaging studies such as computed tomography or magnetic resonance imaging allow the volumetric assessment of the liver segments, only indirect information is provided concerning the quality of the liver parenchyma and its actual functional capacity. Assessment of liver function is therefore crucial in the preoperative workup of patients who require extensive liver resection and in whom portal vein embolization is considered. This review deals with the modalities currently available for the measurement of liver function...
December 2017: Visceral Medicine
https://www.readbyqxmd.com/read/29342984/amaranthus-caudatus-stimulates-insulin-secretion-in-goto-kakizaki-rats-a-model-of-diabetes-mellitus-type-2
#11
Silvia Zambrana, Lena C E Lundqvist, Virginia Veliz, Sergiu-Bogdan Catrina, Eduardo Gonzales, Claes-Göran Östenson
Diabetes Mellitus Type 2 prevalence is increasing worldwide; thus efforts to develop novel therapeutic strategies are required. Amaranthus caudatus (AC) is a pseudo-cereal with reported anti-diabetic effects that is usually consumed in food preparations in Bolivia. This study evaluated the anti-diabetic nutraceutical property of an AC hydroethanolic extract that contains mainly sugars and traces of polyphenols and amino acids (as shown by nalysis with liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR)), in type 2 diabetic Goto-Kakizaki (GK) rats and healthy Wistar (W) rats...
January 15, 2018: Nutrients
https://www.readbyqxmd.com/read/29342836/cool-climate-red-wines-chemical-composition-and-comparison-of-two-protocols-for-%C3%A2-h-nmr-analysis
#12
Violetta Aru, Klavs Martin Sørensen, Bekzod Khakimov, Torben Bo Toldam-Andersen, Søren Balling Engelsen
This study investigates the metabolome of 26 experimental cool-climate wines made from 22 grape varieties using two different protocols for wine analysis by proton nuclear magnetic resonance (¹H-NMR) spectroscopy. The wine samples were analyzed as-is (wet) and as dried samples. The NMR datasets were preprocessed by alignment and mean centering. No normalization or scaling was performed. The "wet" method preserved the inherent properties of the samples and provided a fast and effective overview of the molecular composition of the wines...
January 13, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29341926/direct-detection-of-carbon-and-nitrogen-nuclei-for-high-resolution-analysis-of-intrinsically-disordered-proteins-using-nmr-spectroscopy
#13
E B Gibbs, R W Kriwacki
Nuclear magnetic resonance spectroscopy (NMR) is a powerful technique for characterizing the structural and dynamic properties of intrinsically disordered proteins and protein regions (IDPs & IDRs). However, the application of NMR to IDPs has been limited by poor chemical shift dispersion in two-dimensional (2D) 1H-15N heteronuclear correlation spectra. Among the various detection schemes available for heteronuclear correlation spectroscopy, 13C direct-detection has become a mainstay for investigations of IDPs owing to the favorable chemical shift dispersion in 2D 13C'-15N correlation spectra...
January 13, 2018: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/29341913/characterisation-of-pore-structures-of-pharmaceutical-tablets-a-review
#14
REVIEW
Daniel Markl, Alexa Strobel, Rüdiger Schlossnikl, Johan Bøtker, Prince Bawuah, Cathy Ridgway, Jukka Rantanen, Thomas Rades, Patrick Gane, Kai-Erik Peiponen, J Axel Zeitler
Traditionally, the development of a new solid dosage form is formulation-driven and less focus is put on the design of a specific microstructure for the drug delivery system. However, the compaction process particularly impacts the microstructure, or more precisely, the pore architecture in a pharmaceutical tablet. Besides the formulation, the pore structure is a major contributor to the overall performance of oral solid dosage forms as it directly affects the liquid uptake rate, which is the very first step of the dissolution process...
January 13, 2018: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/29341713/field-induced-instability-of-a-gapless-spin-liquid-with-a-spinon-fermi-surface
#15
M Gomilšek, M Klanjšek, R Žitko, M Pregelj, F Bert, P Mendels, Y Li, Q M Zhang, A Zorko
The ground state of the quantum kagome antiferromagnet Zn-brochantite, ZnCu_{3}(OH)_{6}SO_{4}, which is one of only a few known spin-liquid (SL) realizations in two or three dimensions, has been described as a gapless SL with a spinon Fermi surface. Employing nuclear magnetic resonance in a broad magnetic-field range down to millikelvin temperatures, we show that in applied magnetic fields this enigmatic state is intrinsically unstable against a SL with a full or a partial gap. A similar instability of the gapless Fermi-surface SL was previously encountered in an organic triangular-lattice antiferromagnet, suggesting a common destabilization mechanism that most likely arises from spinon pairing...
September 29, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/29341105/metabolomic-characterization-of-human-hippocampus-from-drug-resistant-epilepsy-with-mesial-temporal-seizure
#16
Julien Detour, Caroline Bund, Charles Behr, Hélène Cebula, Ercument A Cicek, Maria-Paola Valenti-Hirsch, Béatrice Lannes, Benoît Lhermitte, Astrid Nehlig, Pierre Kehrli, François Proust, Edouard Hirsch, Izzie-Jacques Namer
OBJECTIVE: Within a complex systems biology perspective, we wished to assess whether hippocampi with established neuropathological features have distinct metabolome. Apparently normal hippocampi with no signs of sclerosis (noHS), were compared to hippocampal sclerosis (HS) type 1 (HS1) and/or type 2 (HS2). Hippocampus metabolome from patients with epilepsy-associated neuroepithelial tumors (EANTs), namely, gangliogliomas (GGs) and dysembryoplastic neuroepithelial tumors (DNTs), was also compared to noHS epileptiform tissue...
January 17, 2018: Epilepsia
https://www.readbyqxmd.com/read/29341030/new-tirucallane-type-triterpenoids-from-guarea-guidonia
#17
Vanessa Hernandez, Marinella De Leo, Roberta Cotugno, Alessandra Braca, Nunziatina De Tommasi, Lorella Severino
The aerial parts of Guarea guidonia afforded three new tirucallane-type triterpenoids: 3,4-seco-tirucalla-4(28),8(9),24(25)-trien-7α,11α-dihydroxy-21,23-epoxy-3,11-olide, named guareolide (1: ), 3,4-seco-tirucalla-4(28),7(8),24(25)-trien-21-hydroxy-21,23-epoxy-3-oic acid, named guareoic acid A (2: ), and 3,4-seco-tirucalla-4(28),7(8),24(25)-trien-21,23-epoxy-3-oic acid, named guareoic acid B (3: ), of which 1: possessed an unusual seven-membered lactone ring. Seven known terpenes were also isolated and characterized as flindissone, 7-acetyldihydronomilin, picroquassin E, boscartol C, and cneorubins A, B, and X...
January 16, 2018: Planta Medica
https://www.readbyqxmd.com/read/29341016/oxygenation-imaging-by-nuclear-magnetic-resonance-methods
#18
Heling Zhou, Nuria Arias-Ramos, Pilar López-Larrubia, Ralph P Mason, Sebastián Cerdán, Jesús Pacheco-Torres
Oxygen monitoring is a topic of exhaustive research due to its central role in many biological processes, from energy metabolism to gene regulation. The ability to monitor in vivo the physiological distribution and the dynamics of oxygen from subcellular to macroscopic levels is a prerequisite to better understand the mechanisms associated with both normal and disease states (cancer, neurodegeneration, stroke, etc.). This chapter focuses on magnetic resonance imaging (MRI) based techniques to assess oxygenation in vivo...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29339381/cholecystokinin-is-involved-in-triglyceride-fatty-acid-uptake-by-rat-adipose-tissue
#19
Adrian Plaza, Beatriz Merino, Victoria Cano, Gema Domínguez, Javier Pérez-Castells, Maria S Fernandez-Alfonso, Coralie Sengenès, Julie A Chowen, Mariano Ruiz-Gayo
The incorporation of plasma triglyceride (TG) fatty acids to white adipose tissue (WAT) depends on lipoprotein lipase (LPL), which is regulated by angiopoietin-like protein-4 (ANGPTL-4), an unfolding molecular chaperone that converts active LPL dimers into inactive monomers. The production of ANGPTL-4 is promoted by fasting and repressed by feeding. We hypothesized that the postprandial hormone cholecystokinin (CCK) facilitates the storage of dietary TG fatty acids in WAT by regulating the activity of the LPL/ANGPTL-4 axis and that it does so by acting directly on CCK receptors in adipocytes...
January 16, 2018: Journal of Endocrinology
https://www.readbyqxmd.com/read/29339179/primary-diffuse-leptomeningeal-atypical-teratoid-rhabdoid-tumor-diagnosed-by-cerebrospinal-fluid-cytology-case-report-with-molecular-genetic-analysis
#20
Ran Tomomasa, Satoshi Nakata, Sumihito Nobusawa, Keishi Horiguchi, Nozomi Matsumura, Hayato Ikota, Junko Hirato, Yuhei Yoshimoto, Hideaki Yokoo
Atypical teratoid/rhabdoid tumors (AT/RT) are rare malignant neoplasms that mainly affect infants and young children, and are typically located in the cerebellar hemispheres. These tumors are histologically characterized by varying proportions of rhabdoid cells, and nuclear INI1 immunonegativity. Here, we report a case of a 15-year-old male with primary diffuse leptomeningeal AT/RT. The patient had symptoms similar to those of meningitis. Magnetic resonance imaging revealed leptomeningeal thickening. Cytological examination using cerebrospinal fluid was repeatedly performed and revealed rhabdoid cells with loss of INI1 reactivity, and shortly after, the diagnosis of AT/RT was confirmed by tissue biopsy...
January 12, 2018: Human Pathology
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