Search results for "two-dimensional"
showing 10 items of 350 documents
Chemical constituents from leaves and root bark of Trichilia monadelpha (Meliaceae)
2018
Abstract Two new limonoid derivatives designated, monadelphin A (1) and monadelphin B (2) and two new sesquiterpene derivatives named trichins A (3) and B (4) were isolated together with six known compounds (5–10) from the mixture of methylene chloride/methanol (1:1) extract of leaves and root bark of Trichilia monadelpha (Meliaceae) collected in Cameroon. The structures of the new compounds were unambiguously established by detailed spectroscopic analysis including 1D and 2D NMR data in conjunction with high resolution mass spectrometry data and by comparison of these data with those of related compounds described in the literature. Compounds 1–4 were screened for their cytotoxic potential…
Leucine aminopeptidase is an immunodominant antigen of Fasciola hepatica excretory and secretory products in human infections.
2007
ABSTRACT The liver fluke Fasciola hepatica parasitizes humans and ruminant livestock worldwide, and it is now being considered a reemerging zoonotic disease, especially in areas in which it is endemic, such as South America. This study investigates the immune response to excretory and secretory products produced by F. hepatica in a group of patients from the Peruvian Altiplano, where the disease is highly endemic. Using a proteomic approach and immunoblotting techniques, we have identified the enzymes leucine aminopeptidase (LAP) and phosphoenolpyruvate carboxykinase as immunodominant antigens recognized by sera from fasciolosis patients. An indirect enzyme-linked immunosorbent assay using …
Nanotexturing To Enhance Photoluminescent Response of Atomically Thin Indium Selenide with Highly Tunable Band Gap.
2016
Brotons-Gisbert, Mauro et al.
Hederagenin glycosides from the fruits of Blighia unijugata
2019
Abstract A phytochemical investigation of Blighia unijugata led to the isolation of eleven hederagenin glycosides. Among these compounds, six are previously undescribed, two are described in their native forms for the first time and three are known whereas firstly isolated from Blighia unijugata. The structure of the undescribed compounds was elucidated on the basis of 2D NMR and mass spectrometry analyses as 3-O-β-D-xylopyranosyl-(1 → 3)-α-L-arabinopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosylhederagenin, 3-O-β-D-xylopyranosyl-(1 → 3)-α-L-arabinopyranosyl-(1 → 4)-3-O-acetyl-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyr…
Nuclear magnetic resonance spectroscopic study of beta-lactoglobulin interactions with two flavor compounds, gamma-decalactone and beta-ionone.
2002
Interactions between a well-characterized protein, beta-lactoglobulin, and two flavor compounds, beta-ionone and gamma-decalactone, were studied by 2D NMR spectroscopy. NMR spectra were recorded in aqueous solution (pH 2.0, 12 mM NaCl, 10% D(2)O) under conditions such that beta-lactoglobulin is present in a monomeric state. TOCSY and NOESY spectra were recorded on the protein and the complexes between protein and ligands. The spectra of the NH-CH(alpha) region showed the cross-signals due to the coupling between N- and C-bonded protons in the polypeptide backbone. The observed chemical shift variations in the presence of ligands can be assigned to changes in the protein conformation. It app…
High-resolution solution NMR structure of the Z domain of staphylococcal protein A
1997
Staphylococcal protein A (SpA) is a cell-wall-bound pathogenicity factor from the bacterium Staphylococcus aureus. Because of their small size and immunoglobulin (IgG)-binding activities, domains of protein A are targets for protein engineering efforts and for the development of computational approaches for de novo protein folding. The NMR solution structure of an engineered IgG-binding domain of SpA, the Z domain (an analog of the B domain of SpA), has been determined by simulated annealing with restrained molecular dynamics on the basis of 671 conformational constraints. The Z domain contains three well-defined alpha-helices corresponding to polypeptide segments Lys7 to Leu17 (helix 1), G…
Polyketide Derivatives from Mangrove Derived Endophytic Fungus Pseudopestalotiopsis theae
2020
Chemical investigation of secondary metabolites from the endophytic fungus Pseudopestalotiopsis theae led to the isolation of eighteen new polyketide derivatives, pestalotheols I&ndash
The unique structure of complete lipopolysaccharide isolated from semi-rough Plesiomonas shigelloides O37 (strain CNCTC 39/89) containing (2S)-O-(4-o…
2013
The complete structure of semi-rough lipopolysaccharide (SR-LPS) of Plesiomonas shigelloides CNCTC 39/89 (serotype O37) has been investigated by (1)H and (13)C NMR spectroscopy, matrix-assisted laser-desorption/ionization time-of-flight MS, and chemical methods. The following structure of the single unit of the O-antigen has been established: [formula see text] in which α-D-Lenp is (2S)-O-(4-oxopentanoic acid)-α-D-Glcp residue which has not been found in nature. The absolute configuration of oxopentanoic acid moiety in α-d-Lenose residue was determined by NOESY experiment combined with molecular modeling (MM2 force field). The decasaccharide core is substituted at C-4 of the β-D-Glcp residu…
Detecting ni(ii) in aqueous solution by 3-(2-pyridyl)-[1,2,3]triazolo[1,5-a]pyridine and dimethyl-beta-cyclodextrin
2013
Abstract A new supramolecular sensitizer for nickel(II) ion in aqueous solution based on a pyridyltriazolopyridine-cyclodextrin inclusion complex is proposed. The inclusion complexation behavior, characterization and binding ability of pyridyltriazolopyridine (PTP) with dimethyl-β-cyclodextrin (DMβCD) has been investigated both in solution and solid state by means of absorption, fluorescence, 1H NMR, DSC, and molecular modeling methods. The stoichiometry of the inclusion complex is 1:1, and the thermodynamic studies indicate that the inclusion of PTP is mainly an entropic driven process. The 2D NMR studies revealed that the pyridyl-triazolopyridine is included by both sides of cyclodextrin …
Effect of temperature and ligand protonation on the electronic ground state in Cu( ii ) polymers having unusual secondary interactions: a magnetic an…
2018
International audience; Two new copper(II) polymeric complexes, {[Cu(HPymat)(H2O)](NO3)}n (1) and [Cu2(Pymat)2(H2O)3]n (2), have been synthesized using the Schiff base ligand H2Pymat [H2Pymat = (E)-2-(1-(pyridin-2-yl)-methyleneamino)terephthalic acid]. Complex 1 is a cationic 1D polymer, whereas complex 2 is a two dimensional polymer. Both complexes were crystallographically, spectroscopically and magnetically characterized. Theoretical studies were performed and the catecholase activity of the complexes was also examined. Complex 1 is a ferromagnetically coupled complex with J = 2.8 cm−1 and 2 shows antiferromagnetic coupling with J = −1.6 cm−1. Both complexes show notable features in the …