Optimization of amino acid composition in CHO cell perfusion medium using definitive screening design and 1H NMR-based consumption profiling.

Factors that Restrict the Cell Permeation of Cyclic Prodrugs of an Opioid Peptide, Part 3: Synthesis of Analogs Designed to have Improved Stability to Oxidative Metabolism

High-field proton (1H) nuclear magnetic resonance (NMR) spectroscopy was applied for screening the fatty acyl contents of 33 olive oil samples from five different geographical regions of Turkey to do geographical discrimination analysis. The 1H NMR data were subjected to principal component analysis (PCA) and analysis of variance (ANOVA) to discriminate the origin of olive oils. The combination of discriminative screening by 1H NMR and ANOVA did not require further analysis of olive oil such as gas chromatography (GC). ANOVA was employed for samples from three regions separately: Marmara Region (MR), Aegean Region (AR), and Mediterranean Region (MeR). The best discriminative parameter was the 1H NMR signal of linoleoyl acyl content. Applying both quantitative NMR and statistical analysis indicated that samples from different provinces within each geographical region (MR, AR, and MeR) could be discriminated. Comparing the linoleoyl and oleoyl acyl contents of Turkish olive oils with these of some Mediterranean olive oils showed the possibility of distinguishing the Turkish olive oils. 1H NMR spectra of three olive oil samples with the production years of January 2013, January 2014, and January 2015 were acquired in 2016 for discussing shelf life of olive oil by quantifying fatty acyls content, and determining minor constituents and possible by-products during storage. The effects of altitude and soil quality on fatty acyl contents of olive oil samples from a small olive growing village in Northeastern Turkey were also tested.

Evaluation of a methylation procedure to determine cyclopropenoids fatty acids from Sterculia striata St. Hil. Et Nauds seed oil

Evaluation of a methylation procedure to determine cyclopropenoids fatty acids from Sterculia striata St. Hil. Et Nauds seed oil

Mycobacterium avium subspecies paratuberculosis (MAP), the causative agent of Johne disease in cattle and other ruminants, is proposed to be at least one of the causes of Crohn disease in humans. MAP and Mycobacterium avium subspecies avium, a closely related opportunistic environmental bacterium, share 95% of their genes and exhibit homologies of more than 99% between these genes. The identification of molecules specific for MAP is essential for understanding its pathogenicity and for development of useful diagnostic tools. The application of gas chromatography, mass spectrometry, and nuclear magnetic resonance led to the structural identification of a major cell wall lipopeptide of MAP, termed Para-LP-01, defined as C20 fatty acyl-D-Phe-N-Me-L-Val-L-Ile-L-Phe-L-Ala methyl ester. Variations of this lipopeptide with different fatty acyl moieties (C16 fatty acyl through C17, C18, C19, C21 to C22) were also identified. Besides the specificity of this lipopeptide for MAP, the presence of an N-Me-L-valine represents the first reported N-methylated amino acid within an immunogenic lipopeptide of mycobacteria. Sera from animals with Johne disease, but not sera from uninfected cattle, reacted with this lipopeptide, indicating potential biological importance.

Generic ciprofloxacin tablets contain the stated amount of drug and different impurity profiles: A 19F, 1H and DOSY NMR analysis

Several technologies for the development of new sugarcane cultivars have mainly focused on the increase in productivity and greater disease resistance. Sugarcane cultivars are usually identified by the organography of the leaves and stems, the analysis of peroxidase and esterase isoenzyme activities and the total soluble protein as well as soluble solid content. Nuclear magnetic resonance (NMR) associated with chemometric analysis has proven to be a valuable tool for cultivar assessment. Thus, this article describes the potential of chemometric analysis applied to ¹H high resolution magic angle spinning (HRMAS) and NMR in solution for the investigation of sugarcane cultivars. For this purpose, leaves from eight different cultivars of sugarcane were investigated by ¹H NMR spectroscopy in combination with chemometric analysis. The approach shows to be a useful tool for the distinction and classification of different sugarcane cultivars as well as to access the differences on its chemical composition.

Novel polyhedral oligomeric silsesquioxanes (POSS) decorated with eight terpyridine moieties were synthesized in a one-pot procedure via Heck coupling reaction with the aim of investigating the possible formation of three-dimensional extended supramolecular organizations. The monosubstituted analogue was also prepared and used as a model compound. Both POSS-based nanostructures were extensively characterized via 1H, 13C, and 29Si nuclear magnetic resonance (NMR), ultraviolet-visible spectroscopies and combustion chemical analysis. The assembly of these nanocaged bricks and two different metal ions (Zn2+ and Fe2+) was investigated via 1H NMR as well as absorption and emission spectroscopy. Both mono- and octa-terpyridine-functionalized POSS (O-POSS) displayed interesting photophysical properties. Moreover, under selected conditions, the O-POSS forms stable gels at room temperature and can easily be shaped in the form of a film with potential applications in nanotechnology.

Three-dimensional (3D) perfusable organ models, primarily composed of liver cells, are expected as an efficient tool for in vitro cell-based drug screening and development. Various types of hydrogel-based 3D cell culture systems have been developed, but the lack in proper techniques to form vasculature networks in the hydrogel matrices results in inefficient supply of oxygen and nutrition to the cells. Here we propose a facile strategy to creating a perfusable hydrogel-based liver cell culture system. We utilized a bicontinuous dispersion of an aqueous two-phase system, which was composed of polyethylene glycol (PEG)-rich and gelatin methacrylate (GelMA)-rich phases, to produce cell-encapsulating microporous GelMA-based hydrogels. We successfully encapsulated HepG2 cells in the hydrogel matrix with a high cell viability, and confirmed that the spongious hydrogel was superior to homogeneous hydrogels for 3D cell culture. We performed perfusion culture for the cells encapsulated in the hydrogel sponge, to verify the usability and versatility of the presented hydrogel material for perfusion culture. The presented approach would be useful as a unique tool for developing organs-on-a-chip systems.

Comprehensive metabolomic variations of hawthorn before and after insect infestation based on the combination analysis of 1H NMR and UPLC-MS

Two publications from the same research group reporting on the detection of new possible biomarkers for the early diagnosis of Alzheimer’s disease (AD), based on the analysis of cerebrospinal fluid samples (CSF) with 1H Nuclear Magnetic Resonance (NMR), are at the origin of the present study. The authors observed significant differences in 1H NMR spectra of CSF from AD patients and healthy controls and, thus, proposed some NMR signals (without attribution) as possible biomarkers. However, this work was carried out in non-standardized pH conditions. Our study aims at warning about a possible misinterpretation that can arise from 1H NMR analyses of CSF samples if pH adjustment is not done before NMR analysis. Indeed, CSF pH increases rapidly after removal and is subject to changes over conservation time. We first identify the NMR signals described by the authors as biomarkers. We then focus on the chemical shift variations of their NMR signals as a function of pH in both standard solutions and CSF samples. Finally, a principal component analysis of 1H NMR data demonstrates that the same CSF samples recorded at pH 8.1 and 10.0 are statistically differentiated.

In situ NMR Investigation of the Photoresponse of Perovskite Crystal

Nuclear magnetic resonance (NMR) spectroscopy in combination with chemometrics can be applied in the analysis of complex biological samples in many ways. For example, we can analyze lipids, elucidate their structures, determine their nutritional values, and determine their distribution in blood serum. As lipids are not soluble in water, they are transported in blood as lipid-rich self-assembled particles, divided into different density assemblies from high- to very-low-density lipoproteins (HDL to VLDL), or by combining with serum proteins, such as albumins (human serum albumins (HSA)). Therefore, serum lipids can be analyzed as they are using only a 1:1 (v/v) dilution with a buffer or deuterated water prior to analysis by applying 1H NMR or 1H NMR edited-by-diffusion techniques. Alternatively, lipids can be extracted from the serum using liquid partition equilibrium and then analyzed using liquid-state NMR techniques. Our chapter describes protocols that are used for extraction of blood serum lipids and their quantitative 1H NMR (1H qNMR) analysis in lipid extracts as well as 1H NMR edited by diffusion for direct blood serum lipid analysis.

Nuclear Magnetic Resonance (NMR) spectroscopy is a highly versatile technique for structural elucidation in natural product research. However, its implementation as the ultimate identity test requires the accurate determination of the position and multiplicity of each proton resonance of the compound(s) of interest. In this report, quantitative 1H NMR (qHNMR) and computer-aided spectral analysis are combined to develop an efficient methodology for the complete analysis of 1H NMR signal patterns. This approach, termed 1 H iterative Full Spin Analysis (HiFSA), enables the production of detailed, reproducible 1H NMR profiles, i.e., 1H NMR fingerprints. These high resolution, field independent fingerprints can be used to unambiguously identify natural products in a wide variety of samples, including reference materials, enriched fractions, and crude extracts. Furthermore, they also provide a solid starting point for the characterization of structurally related unknown compounds. Illustrative examples of 1H NMR fingerprints of natural products and their generation by HiFSA will be presented.

Oxygen‐17 and deuterium are two quadrupolar nuclei that are of interest for studying the structure and dynamics of materials by solid‐state nuclear magnetic resonance (NMR). Here, 17O and 2H NMR analyses of crystalline ibuprofen and terephthalic acid are reported. First, improved 17O‐labelling protocols of these molecules are described using mechanochemistry. Then, dynamics occurring around the carboxylic groups of ibuprofen are studied considering variable temperature 17O and 2H NMR data, as well as computational modelling (including molecular dynamics simulations). More specifically, motions related to the concerted double proton jump and the 180° flip of the H‐bonded (–COOH)2 unit in the crystal structure were looked into, and it was found that the merging of the C=O and C–OH 17O resonances at high temperatures cannot be explained by the sole presence of one of these motions. Lastly, preliminary experiments were performed with a 2H–17O diplexer connected to the probe. Such configurations can allow, among others, 2H and 17O NMR spectra to be recorded at different temperatures without needing to tune or to change probe configurations. Overall, this work offers a few leads which could be of use in future studies of other materials using 17O and 2H NMR.