Magnetic Nuclear Resonance

The rheological and morphological characteristics of Ca-crosslinked alginate hydrogels with two different M/G ratios, α-L-guluronate (G)-rich and β-D-mannuronate (M)-rich, each with one alginic acid concentration, were investigated. It was found that the stiffness and elasticity of alginate hydrogels are derived from the thickness and density of the fibril network structures. In aqueous alginate solution, ball-like aggregates of alginates are present. Time-resolved small-angle X-ray scattering and time-domain nuclear magnetic resonance measurements suggest that the disaggregation of alginate aggregates and loose fibrillation occur in the early stage of the sol-gel transition...

Human La-related protein 1 (HsLARP1) is involved in post-transcriptional regulation of certain 5' terminal oligopyrimidine (5'TOP) mRNAs as well as other mRNAs and binds to both the 5'TOP motif and the 3'-poly(A) tail of certain mRNAs. HsLARP1 is heavily involved in cell proliferation, cell cycle defects, and cancer, where HsLARP1 is significantly upregulated in malignant cells and tissues. Like all LARPs, HsLARP1 contains a folded RNA binding domain, the La motif (LaM). Our current understanding of post-transcriptional regulation that emanates from the intricate molecular framework of HsLARP1 is currently limited to small snapshots, obfuscating our understanding of the full picture on HsLARP1 functionality in post-transcriptional events...

OBJECTIVE: The evidence regarding the associations of circulating metabolic biomarkers with hypertension risk is scarce. We aimed to examine the associations between circulating metabolites and risk of hypertension. METHODS: We included 49 422 individuals free of hypertension at baseline with a mean (SD) age of 53.5 (8.0) years from the UK Biobank. Nuclear magnetic resonance spectroscopy was used to quantify 143 individual metabolites. Multivariable-adjusted Cox regression models were used to estimate hazard ratios and 95% confidence intervals (CIs)...

We use a combination of one- and two-dimensional solid-state nuclear magnetic resonance (NMR) spectroscopy and density functional theory (DFT) calculations to obtain a full assignment of the 1 H and 13 C signals for solid (+)-usnic acid, which contains two molecules in the asymmetric unit. By combining through-space 1 H-1 H correlation data with computation it is possible to assign signals not just to the same molecules (relative assignment) but to assign the signals to specific crystallographic molecules (absolute assignment)...

Phytochemical data for Ficus deltoidea Jack, a plant widely studied for its anti-hyperglycemic effect, are scarce. In the pursuit of characterizing the chemical constituents of this species, extraction and purifications were conducted using multiple chromatographic procedures on selected varieties (var. deltoidea , var. kunstleri and var. trengganuensis ). Twenty-two constituents were unambiguously identified through NMR, MS and UV data. These included gallocatechin ( S1 ), afzelechin-4-8″-gallocatechin ( S2 ), catechin ( S3 ), afzelechin-4-8″-catechin ( S4 ), afzelechin ( S5 ), epicatechin ( S6 ), hovetrichoside C ( S7 ), 6,8-di- C -glucopyranosylapigenin (vicenin-2) ( S8 ), afzelechin-4-8″-epiafzelechin ( S9 ), epiafzelechin ( S10 ), 6- C -xylopyranosyl-8- C -glucopyranosylapigenin (vicenin-1) ( S11 ), orientin ( S13 ), schaftoside ( S14 ), 6- C -glucopyranosyl-8- C -xylopyranosylapigenin (vicenin-3) ( S16 ), vitexin ( S17 ), vitexin 2″- O -rhamnoside ( S19 ), isovitexin 2″- O -rhamnoside ( S20 ), 6,8-di- C -arabinopyranosylapigenin ( S21 ), 6,8-di- C -xylopyranosylapigenin ( S22 ), 6- C -arabinopyranosyl-8- C -xylopyranosylapigenin ( S23 ), rhoifolin ( S24 ) and cerberic acid A ( S26 )...

BACKGROUND: Lower socioeconomic position (SEP) associates with adverse pregnancy and perinatal outcomes and with less favourable metabolic profile in nonpregnant adults. Socioeconomic differences in pregnancy metabolic profile are unknown. We investigated association between a composite measure of SEP and pregnancy metabolic profile in White European (WE) and South Asian (SA) women. METHODS: We included 3,905 WE and 4,404 SA pregnant women from a population-based UK cohort...

The BRCA1 carboxyl-terminal (BRCT) domain, an evolutionarily conserved structural motif, is ubiquitous in a multitude of proteins spanning prokaryotic and eukaryotic organisms. In Mycobacterium tuberculosis (Mtb), BRCT domain plays a pivotal role in the catalytic activity of the NAD+-dependent DNA ligase (LigA). LigA is pivotal in DNA replication, catalyzing the formation of phosphodiester bonds in Okazaki fragments and repairing single-strand breaks in damaged DNA, essential for the survival of Mtb. Structural and functional aspects of LigA unveil its character as a highly modular protein, undergoing substantial conformational changes during its catalytic cycle...

BACKGROUND: Glomerulonephritis inherently leads to the development of chronic kidney disease. It is the second most common diagnosis in patients requiring renal replacement therapy in the United Kingdom. Metabolomics and proteomics can characterise, identify and quantify an individual's protein and metabolite make-up. These techniques have been optimised and can be performed on samples including kidney tissue, blood and urine. Utilising omic techniques in nephrology can uncover disease pathophysiology and transform the diagnostics and treatment options for glomerulonephritis...

ETHNOPHARMACOLOGICAL RELEVANCE: The use of medicinal plants for central nervous system (CNS)-related ailments, such as epilepsy and anxiety, is prevalent in South Africa. Plants from the Lamiaceae family are commonly used for their therapeutic benefits. Leonotis leonurus (L.) R.Br. has been reported in ethnobotanical literature to have anticonvulsant and anxiolytic effects through the inhalation of pyrolysis products obtained by combustion of the aerial parts. AIM AND OBJECTIVES: To explore the chemical profiles and CNS activity of the smoke extract and isolated constituents of L...

Flavin mononucleotide (FMN) is a ubiquitous blue-light pigment due to its ability to drive one- and two-electron transfer reactions. In both light-oxygen-voltage (LOV) domains of phototropin from the green algae Chlamydomonas reinhardtii , FMN is noncovalently bound. In the LOV1 cysteine-to-serine mutant (C57S), light-induced electron transfer from a nearby tryptophan occurs, and a transient spin-correlated radical pair (SCRP) is formed. Within this photocycle, nuclear hyperpolarization is created by the solid-state photochemically induced dynamic nuclear polarization (photo-CIDNP) effect...

The protist Euglena gracilis has various trophic modes including heterotrophy and photoheterotrophy. To investigate how cultivation mode influences metabolic regulation, the chemical composition of cellular metabolites of Euglena gracilis grown under heterotrophic and photoheterotrophic conditions was monitored from the early exponential phase to the mid-stationary phase using two different techniques, i.e, nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HRMS). The combined metabolomics approach allowed an in-depth understanding of the mechanism of photoheterotrophic and heterotrophic growth for biomolecule production...

Li3 Y1- x In x Cl6 undergoes a phase transition from trigonal to monoclinic via an intermediate orthorhombic phase. Although the trigonal yttrium containing the end member phase, Li3 YCl6 , synthesized by a mechanochemical route, is known to exhibit stacking fault disorder, not much is known about the monoclinic phases of the serial composition Li3 Y1- x In x Cl6 . This work aims to shed light on the influence of the indium substitution on the phase evolution, along with the evolution of stacking fault disorder using X-ray and neutron powder diffraction together with solid-state nuclear magnetic resonance spectroscopy, studying the lithium-ion diffusion...

Serratiomycin ( 1 ) is an antibacterial cyclic depsipeptide, first discovered from a Eubacterium culture in 1998. This compound was initially reported to contain l-Leu, l-Ser, l- allo -Thr, d-Phe, d-Ile, and hydroxydecanoic acid. In the present study, 1 and three new derivatives, serratiomycin D1-D3 ( 2 - 4 ), were isolated from a Serratia sp. strain isolated from the exoskeleton of a long-horned beetle. The planar structures of 1 - 4 were elucidated by using mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy...

ConspectusMagnetic resonance techniques represent a fundamental class of spectroscopic methods used in physics, chemistry, biology, and medicine. Electron paramagnetic resonance (EPR) is an extremely powerful technique for characterizing systems with an open-shell electronic nature, whereas nuclear magnetic resonance (NMR) has traditionally been used to investigate diamagnetic (closed-shell) systems. However, these two techniques are tightly connected by the electron-nucleus hyperfine interaction operating in paramagnetic (open-shell) systems...

Aspergillus flavus contamination in agriculture and food industries poses threats to human health, leading to a requirement of a safe and effective method to control fungal contamination. Chitosan-based nitrogen-containing derivatives have attracted much attention due to their safety and enhanced antimicrobial applications. Herein, a new benzimidazole-grafted chitosan (BAC) was synthesized by linking the chitosan (CS) with a simple benzimidazole compound, 2-benzimidazolepropionic acid (BA). The characterization of BAC was confirmed by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance spectroscopy (1 H and 13 C NMR)...

The substitution of a single hydrogen atom in a protein by fluorine yields a site-specific probe for sensitive detection by 19 F nuclear magnetic resonance (NMR) spectroscopy, where the absence of background signal from the protein facilitates the detection of minor conformational species. We developed genetic encoding systems for the site-selective incorporation of 4-fluorotryptophan, 5-fluorotryptophan, 6-fluorotryptophan, and 7-fluorotryptophan in response to an amber stop codon and used them to investigate conformational heterogeneity in a designed amino acid binding protein and in flaviviral NS2B-NS3 proteases...

<b>Background and Objective:</b> The SU84 was isolated from the rhizosphere of <i>Curcuma longa</i> and identified to be <i>Streptomyces</i> sp. via analysis of its 16S rDNA sequence, chemotaxonomy and morphology. This study aimed to isolate major compounds from the extract culture of strain SU84 and evaluate their antibacterial activity. <b>Materials and Methods:</b> The TLC and silica gel column chromatography were used to purify major compounds, elucidate 1,3-dihydroxy-,2',2'-dimethylpyrano-(5,6)-xanthone (compound <b>1</b>) and lupeol (compound <b>2</b>) using mass spectrometry and nuclear magnetic resonance...

Magnetic nanocomposites (MNC) are promising theranostic platforms with tunable physicochemical properties allowing for remote drug delivery and multimodal imaging. Here, we developed doxorubicin-loaded Fe3 O4 -Au MNC (DOX-MNC) using electron beam physical vapor deposition (EB-PVD) in combination with magneto-mechanochemical synthesis to assess their antitumor effect on Walker-256 carcinosarcoma under the influence of a constant magnetic (CMF) and electromagnetic field (EMF) by comparing tumor growth kinetics, magnetic resonance imaging (MRI) scans and electron spin resonance (ESR) spectra...

Crystallization is a widely used purification technique in the manufacture of active pharmaceutical ingredients (APIs) and precursor molecules. However, when impurities and desired compounds have similar molecular structures, separation by crystallization may become challenging. In such cases, some impurities may form crystalline solid solutions with the desired product during recrystallization. Understanding the molecular structure of these recrystallized solid solutions is crucial to devise methods for effective purification...

BACKGROUND: For patients with complete breast resection, conventional contrast-enhanced T1-weighted imaging (CE-T1WI) with frequency-selective spectral attenuated inversion recovery (SPAIR) provides limited fat suppression on the postoperative side due to the uneven skin surface, inhomogeneous tissue environment, and frequency-selective feature of the SPAIR scheme, leading to difficulties in precise diagnosis. This study aimed to investigate the image quality and performance of the Dixon method compared with SPAIR in breast high-resolution CE-T1WI for mastectomy patients...