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Takuma Suzuki, Seiya Yoshida, Takuya Koseki, Takako Aboshi, Tetsuya Murayama, Unang Supratman, Yoshihito Shiono
Four novel cylindropyrone A (1), 10'-hydroxyilicicolinic acid D (3), cylindrolactones A (4) and B (5), together with known dihydroinfectopyrone (2) were isolated from the culture of Cylindrocarpon sp. SY-39 from a driftwood. Their structures were elucidated using 1D- and 2D-NMR spectroscopy. Compound 3 showed antimicrobial activity against Staphylococcus aureus with MIC value of 5.0 μg/ml. This article is protected by copyright. All rights reserved.
December 13, 2017: Chemistry & Biodiversity
Stuart J Elliott, Christian Bengs, Karel Kouril, Benno Meier, Shamim Alom, Richard J Whitby, Malcolm Harris Levitt
The 17O isotopomer of the water-endofullerene H2O@C60 displays a remarkable proton NMR spectrum, with six well resolved peaks. These peaks are due to the J-coupling between the water protons and the 17O nucleus, which has spin-5/2. The resolution of these peaks is enabled by the suppression of water proton exchange by the fullerene cage. The six peaks display an unusual pattern of linewidths, which we model by a Liouville-space treatment of scalar relaxation due to quadrupolar relaxation of the 17O nuclei. The data are consistent with rotational diffusion of the water molecule on the sub-picosecond timescale...
December 13, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Erica F Osaku, Rafael A Menolli, Claudia R L de M Costa, Fernando Henrique G Tessaro, Renan H de Melo, Alex E do Amaral, Péricles A D Duarte, Arquimedes Paixão de Santana Filho, Andrea Caroline Ruthes, José Luis da C Silva, Rosiane G Mello
Paecilomyces variotii is a filamentous fungus that occurs worldwide in soil and decaying vegetation. Optimization of the fermentation process for exopolysaccharide (EPS) production from the fungus P. variotii, structure determination and immuno-stimulating activity of EPS were performed. Response surface methodology (RSM) coupled with central composite design (CCD) was used to optimize the physical and chemical factors required to produce EPS in submerged fermentation. Preliminary investigations to choose the three factors for the present work were made using a factorial experimental design...
December 13, 2017: Antonie Van Leeuwenhoek
Jae B Park
p38 Mitogen-activated protein kinase (p38 MAPK) is a protein kinase critically involved in the progress of inflammation/stress-associated diseases. Our data suggested that javamide analogues may contain strong anti-inflammation activities, but there is little information about their effects on p38 MAPK. Therefore, in this paper, the effects of thirty javamide analogues on p38 MAPK were investigated using in silico screening and in vitro p38 MAPK assay methods. The javamide analogues were synthesized and their chemical structures were confirmed using nuclear magnetic resonance (NMR) spectroscopic methods...
December 13, 2017: International Journal of Molecular Sciences
Mattia Mori, Lesia Kovalenko, Savina Malancona, Francesco Saladini, Davide De Forni, Manuel Pires, Nicolas Humbert, Eleonore Real, Thomas Botzanowski, Sarah Cianférani, Alessia Giannini, Maria Chiara Dasso Lang, Giulia Cugia, Barbara Poddesu, Franco Lori, Maurizio Zazzi, Steven Harper, Vincenzo Summa, Yves Mély, Maurizio Botta
HIV/AIDS is still one of the leading causes of death worldwide. Current drugs that target the canonical steps of HIV-1 life cycle are efficient in blocking viral replication, but are unable to eradicate HIV-1 from infected patients. Moreover, drug resistance (DR) is often associated with the clinical use of these molecules, thus raising the need for novel drug candidates as well as novel putative drug targets. In this respect, pharmacological inhibition of the highly conserved and multifunctional nucleocapsid protein (NC) of HIV-1 is considered a promising alternative to current drugs, particularly to overcome DR...
December 13, 2017: ACS Chemical Biology
Yixiang Liu, Joshua Rose, Shaojia Huang, Yangbo Hu, Qiong Wu, Dan Wang, Conggang Li, Maili Liu, Pei Zhou, Ling Jiang
Histidine kinases are key regulators in the bacterial two-component systems that mediate the cellular response to environmental changes. The vast majority of the sensor histidine kinases belong to the bifunctional HisKA family, displaying both kinase and phosphatase activities toward their substrates. The molecular mechanisms regulating the opposing activities of these enzymes are not well understood. Through a combined NMR and crystallographic study on the histidine kinase HK853 and its response regulator RR468 from Thermotoga maritima, here we report a pH-mediated conformational switch of HK853 that shuts off its phosphatase activity under acidic conditions...
December 13, 2017: Nature Communications
Ling-Juan Zhu, Ying Song, Peng Shao, Xue Zhang, Xin-Sheng Yao
Two new phenolics, named matteucens I-J (1-2), were isolated from the 60% EtOH extract of the rhizomes of Matteuccia orientalis (HOOK.) TREV. Their structures were elucidated by means of extensive spectroscopic analysis (HRESIMS, NMR).
December 13, 2017: Journal of Asian Natural Products Research
Mahesh Bhat, Shiddappa Lagamappa Belagali
AIM: Benzothiazole and pyrazoles are two important pharmacophores, the activity can be enhanced by conjugating them. Here, two novel series of the pyrazole-conjugated benzothiazole derivatives were synthesized. RESULTS: Synthesized compounds were characterized by Fourier-transform infrared, LC-MS, 1H NMR and 13C NMR spectroscopic techniques. Synthesized compounds exhibited moderate antimicrobial, antioxidant and excellent anti-TB activities. In in vitro anti-TB activity, 4d and 4e exhibited 1...
December 13, 2017: Future Medicinal Chemistry
Marija Smiljkovic, Minos-Timotheos Matsoukas, Eftichia Kritsi, Urska Zelenko, Simona Golic Grdodolnik, Ricardo Calhelha, Isabel Ferreira, Snezana Sankovic-Babic, Jasmina Glamoclija, Theano Fotopoulou, Maria Koufaki, Panagiotis Zoumpoulakis, Marina Sokovic
Four heteroaromatic compounds bearing nitrate esters were selected using a virtual screening procedure as putative sterol 14α-demethylase (CYP51) Candida albicans inhibitors. Compounds were examined for their inhibition on C. albicans growth and biofilm formation as well as for their toxicity. NMR studies, in silico docking and molecular dynamics simulations were used to further investigate selectivity of compounds to fungal CYP51. All compounds exhibited good antimicrobial properties, indicated with low minimal inhibitory concentrations and ability to inhibit formation of fungal biofilm...
December 13, 2017: ChemMedChem
Charles R Watts, Andrew Gregory, Cole Frisbie, Sándor Lovas
The conformational space and structural ensembles of amyloid beta (Aβ) peptides and their oligomers in solution are inherently disordered and proven to be challenging to study. Optimum force field selection for molecular dynamics (MD) simulations and the biophysical relevance of results are still unknown. We compared the conformational space of the Aβ(1-40) dimers by 300 ns replica exchange MD simulations at physiological temperature (310 K) using: the AMBER-ff99sb-ILDN, AMBER-ff99sb*-ILDN, AMBER-ff99sb-NMR, and CHARMM22* force fields...
December 13, 2017: Proteins
Naima G Sharaf, Andrew E Brereton, In-Ja L Byeon, P Andrew Karplus, Angela M Gronenborn
In the original publication of the article, the given name and family name of the author P. Andrew Karplus was published incorrectly. The name should read as "P. Andrew" - Given name and "Karplus" - Family name.
December 12, 2017: Journal of Biomolecular NMR
Ramendra Singh Parmar, Charu Singh
Actinomycetes, a large group of filamentous bacteria account for 70-80% of secondary metabolites available commercially. The present investigation was undertaken with an aim to identify and characterize pigment from actinomycetes. Actinomycetes were isolated from rhizosphere soil samples collected from different regions of Madhya Pradesh state. Out of 85 actinomycetes, only 5 actinomycetes showed pigment production and based on diffusible pigment production ability one actinomycete ARITM02 was selected. The extraction of pigment was done by solvent extraction method using methanol and purified by TLC and column chromatography...
March 2018: Biochemistry and Biophysics Reports
Herbert Júnior Dias, Ricardo Stefani, José Carlos Tomaz, Ricardo Vessecchi, Antônio Eduardo Miller Crotti
We investigated the fragmentation of the eudesmanolide-type sesquiterpene lactones 1α-(4-hydroxymethacryloyloxy)-3α,4α-epoxy-8α-hydroxyeudesm-11(13)-6α,12-olide (1) and 1α-(2,3-epoxyangeloyloxy)-4α,15-epoxy-8α-hydroxyeudesm-11(13)-6α,12-olide (2) by electrospray ionization tandem mass spectrometry (ESI-MS/MS). The elimination of the different ester substituent at C(1) directly from protonated 1 and 2 (A) led to the formation of two regioisomer product ions B (A - RCO2H). Further fragmentation of B resulted from consecutive eliminations of H2O and CO molecules...
2017: Journal of Analytical Methods in Chemistry
Andrew G M Rankin, Paul B Webb, Daniel M Dawson, Jasmine Viger-Gravel, Brennan J Walder, Lyndon Emsley, Sharon E Ashbrook
Isotopic enrichment of 29Si and DNP-enhanced NMR spectroscopy are combined to determine the detailed surface structure of a silicated alumina catalyst. The significant sensitivity enhancement provided by DNP is vital to the acquisition of multinuclear and multidimensional experiments that provide information on the atomic-level structure of the species present at the surface. Isotopic enrichment not only facilitates spectral acquisition, particularly given the low (1.5 wt %) Si loading, but also enables spectra with higher resolution than those acquired using DNP to be obtained...
October 19, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Azim Ziyaei Halimehjani, Martin Dračínský, Petr Beier
A one-pot three-component route for the synthesis of S-trifluoromethyl dithiocarbamates by the reaction of secondary amines, carbon disulfide and Togni's reagent is described. The reactions proceed in moderate to good yields. A similar reaction using a primary aliphatic amine afforded the corresponding isothiocyanate in high yield. A variable temperature NMR study revealed a rotational barrier of 14.6, 18.8, and 15.9 kcal/mol for the C-N bond in the dithiocarbamate moiety of piperidine, pyrrolidine, and diethylamine adducts, respectively...
2017: Beilstein Journal of Organic Chemistry
Przemysław J Boratyński
Scoring permutations of experimental chemical shift deviations and DFT/GIAO calculated deviations of isotropic shieldings for sets of four diastereomers can help to assign their relative configurations. This method was exercised on a set of diastereomeric Cinchona alkaloid derivatives, where 13C NMR data always identified the proper configuration. The presented approach is also an attempt to quantify the assignment by exclusion.
2017: Beilstein Journal of Organic Chemistry
Paweł Chmielarz, Tomasz Pacześniak, Katarzyna Rydel-Ciszek, Izabela Zaborniak, Paulina Biedka, Andrzej Sobkowiak
The flavonoid-based macroinitiator was received for the first time by the transesterification reaction of quercetin with 2-bromoisobutyryl bromide. In accordance with the "grafting from" strategy, a naturally-occurring star-like polymer with a polar 3,3',4',5,6-pentahydroxyflavone core and hydrophobic poly(tert-butyl acrylate) (PtBA) side arms was synthesized via a simplified electrochemically mediated ATRP (seATRP), utilizing only 78 ppm by weight (wt) of a catalytic CuII complex. To demonstrate the possibility of temporal control, seATRP was carried out utilizing a multiple-step potential electrolysis...
2017: Beilstein Journal of Organic Chemistry
Xinli Pan, Nicole Domin, Sebastian Schieferdecker, Hirokazu Kage, Martin Roth, Markus Nett
The genome of the predatory bacterium Herpetosiphon aurantiacus 114-95T harbors a number of biosynthesis genes, including four terpene cyclase genes. To identify the terpenes biosynthesized from H. aurantiacus 114-95T, we fed the strain with 13C-labeled glucose and, subsequently, searched for characteristic mass shifts in its metabolome. This approach led to the discovery of a new natural product, of which the isotope pattern is indicative for a diterpene originating from the methylerythritol phosphate pathway...
2017: Beilstein Journal of Organic Chemistry
Vladimir Kubyshkin, Nediljko Budisa
Fluorinated moieties are highly valuable to chemists due to the sensitive NMR detectability of the 19F nucleus. Fluorination of molecular scaffolds can also selectively influence a molecule's polarity, conformational preferences and chemical reactivity, properties that can be exploited for various chemical applications. A powerful route for incorporating fluorine atoms in biomolecules is last-stage fluorination of peptide scaffolds. One of these methods involves esterification of the C-terminus of peptides using a diazomethane species...
2017: Beilstein Journal of Organic Chemistry
Daniele Sporck, Felipe A M Reinoso, Jorge Rencoret, Ana Gutiérrez, José C Del Rio, André Ferraz, Adriane M F Milagres
Background: New biorefinery concepts are necessary to drive industrial use of lignocellulose biomass components. Xylan recovery before enzymatic hydrolysis of the glucan component is a way to add value to the hemicellulose fraction, which can be used in papermaking, pharmaceutical, and food industries. Hemicellulose removal can also facilitate subsequent cellulolytic glucan hydrolysis. Results: Sugarcane bagasse was pretreated with an alkaline-sulfite chemithermomechanical process to facilitate subsequent extraction of xylan by enzymatic or alkaline procedures...
2017: Biotechnology for Biofuels
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