Analytical science advances最新文献

Under different concentrations of the base potassium deuteroxide KOD, the progress of reactions, such as enolization, D-substitution, isomerization, and conformational changes of diketopiperazine cyclo(L-Pro-L-Xxx) and cyclo(D-Pro-L-Xxx) (Xxx = Phe, Tyr) in D₂O solution, was investigated by ¹H nuclear magnetic resonance (NMR). Cyclo(L-Pro-L-Xxx) is mostly isomerized to cyclo(D-Pro-L-Xxx) in D₂O solution, whereas cyclo(D-Pro-L-Xxx) is only slightly isomerized to cyclo(L-Pro-L-Xxx) even under stronger basic conditions. After adding a deuterated organic solvent (CD₃COCD₃, CD₃SOCD₃ or CD₃OD) to a D₂O solution of cyclo(L-Pro-L-Xxx), cyclo(D-Pro-L-Xxx), or increasing the temperature of the D₂O solution, CH-π interaction between H₉ and the benzene ring of cyclo (D-Pro-L-Xxx) was stronger than that between H_8α and the benzene ring of cyclo(L-Pro-L-Xxx).

Medicinal plant metabolomics has emerged as a goldmine for the natural product chemists. It provides a pool of bioactive phytoconstituents leading to accelerated novel discoveries and the elucidation of a variety of biosynthetic pathways. Further, it also acts as an innovative tool for herbal medicine's scientific validation and quality assurance. This review highlights different strategies and analytical techniques employed in the practice of metabolomics. Further, it also discusses several other applications and advantages of metabolomics in the area of natural product chemistry. Additional examples of integrating metabolomics with multivariate data analysis techniques for some Indian medicinal plants are also reviewed. Recent technical advances in mass spectrometry-based hyphenated techniques, nuclear magnetic resonance-based techniques, and comprehensive hyphenated technologies for phytometabolite profiling studies have also been reviewed. Mass Spectral Imaging (MSI) has been presented as a highly promising method for high precision in situ spatiotemporal monitoring of phytometabolites. We conclude by introducing GNPS (Global Natural Products Social Molecular Networking) as an emerging platform to make social networks of related molecules, to explore data and to annotate more metabolites, and expand the networks to novel “predictive” metabolites that can be validated.

Pharmaco-metabolomics uses metabolic phenotypes for the prediction of inter-individual variations in drug response and helps in understanding the mechanisms of drug action. The field has made significant progress over the last 14 years with numerous studies providing clinical evidence for personalised medicine. However, discovered pharmaco-metabolomic biomarkers are not yet translated into clinics due to a lack of large-scale validation. Integration of targeted and untargeted metabolomics workflows into pharmacokinetic analysis and drug development can advance the field from bench to bedside. Also, Indian pharmaceutical research and its bioanalytical infrastructure are in a position to take on these opportunities by addressing challenges such as appropriate training and regulatory compliance.

Inborn errors of metabolism (IEMs) are a group of disorders caused by disruption of metabolic pathways, which leads to accumulation, decreased circulating levels, or increased excretion of metabolites as a consequence of the underlying genetic defects. These heterogeneous groups of disorders cause significant neonatal and infant mortality across the whole world and it is of utmost concern for developing countries like India owing to lack of awareness and standard preventive strategies like newborn screening (NBS). Though the predictive cumulative incidence of IEMs is said to be ∼1:800 newborns, data pertaining to the true prevalence of individual IEMs is not available in the context of Indian population. There is a need for a large population-based study to get a clear picture of the prevalence of different IEMs. One of the best ways to screen for IEMs is by applying advanced liquid chromatography-mass spectrometry (LC-MS) technology using a quantitative metabolomics approaches such as selected or multiple reaction monitoring (SRM or MRM). Recent developments in LC-MS/MRM based quantification of marker metabolites in newborns have opened a novel opportunity to screen multiple disorders simultaneously from a minuscule volume of biological fluids. In this review article, we have highlighted how LC-MS/MRM based metabolomics approach with its high sensitivity and diagnostic capability can make an impact on the nation's public health through NBS programs.

The compressed sensing (CS) theory requires the signal to be sparse under some transform. For most signals (e.g., speech and photos), the non-adaptive transform bases, such as discrete cosine transform (DCT), discrete Fourier transform (DFT), and Walsh-Hadamard transform (WHT), can meet this requirement and perform quite well. However, one limitation of these non-adaptive transforms is that we cannot leverage domain-specific knowledge to improve CS efficiency. This study presents a task-adaptive eigenvector-based projection (EBP) transform. The EBP basis has an equivalent effect of the principal component loading matrix and can generate a sparse representation in the latent space. In a Raman spectroscopic profiling case study, EBP demonstrates better performance than its non-adaptive counterparts. At the 1% CS sampling ratio (k), the reconstruction relative mean square errors of DCT, DFT, WHT and EBP are 0.33, 0.68, 0.32, and 0.00, respectively. At a fixed k, EBP achieves much better reconstruction quality than the non-adaptive counterparts. For specific domain tasks, EBP can significantly lower the CS sampling ratio and reduce the overall measurement cost.

The cover image is based on the Full Article Quadrupole detection FT-ICR mass spectrometry offers deep profiling of residue oil: A systematic comparison of 2ω 7 Tesla versus 15 Tesla instruments by Jinfeng Ge et al., https://doi.org/10.1002/ansa.202000123.

Chromatographic analysis of therapeutic oligonucleotides is challenging due to the presence of closely related impurities, degradants or metabolites and due to the presence of phosphorothioate bonds, which introduce chiral centers. In the present study, ion pair reversed phase chromatography of oligonucleotides on micropillar array columns was investigated. Two commonly used mobile phase conditions were included. With 16.3 mM triethylamine and 400 mM hexafluoroisopropanol, the separation of 16-mer oligonucleotides differing in the number and positions of phosphorothioate linkages as well as some n-1 and n-2 truncations demonstrated complete suppression of diastereoselectivity. Although the positional phosphorothioate isomers evaluated could not be resolved, an increase in phosphorothioate bonds resulted in more retention. A therapeutic 19-mer RNA sequence with 2′-fluor and 2′-O-methyl modifications showed partial separation of some very close impurities. When using 15 mM triethyl ammonium acetate in the mobile phase, diastereomer selectivity was clearly observed for all analytes. The best result was obtained for the 19-mer RNA therapeutic mimic with four phosphorothioate bonds, since all 16 theoretical diastereomers were clearly observed under the conditions tested. A limited benchmark exercise demonstrated the improved capability of the new micropillar array columns. Therefore, these columns can be positioned as a valuable alternative when challenging oligonucleotide separations are expected.

Mediterranean fruit fly (medfly), Ceratitis capitata, is among the most destructive agricultural pest. The sterile insect technique (SIT) can effectively control medfly populations. To rear healthy medflies for the purpose of SIT, it is essential to supplement B vitamins in the diet. However, the function of the dietary B vitamins in C. capitata larvae is not known. With the microscopic analysis, several organs in the head were examined and the spiracle formation and sensory organs were normally formed between the niacin-supplied and niacin-absent groups. However, formation of the ocular depression was differently developed between the two groups, although the hypostomal sclerite was formed properly. These results signify that niacin deficiency maybe interrupt development of medfly larvae ocular depression. Proteomic analyses using LC MS/MS detected a total of 1845 proteins in two flies. A total of 607 of the 1845 proteins were overexpressed and one third (598 proteins) were downexpressed in the niacin-deficient larvae, while about one third were similarly expressed. Overexpressed proteins in the niacin-deficient larvae included ryanodine receptor 44 F, intergrin-PS, spalt-major homeotic protein, and chiffon protein. One of important overexpressed proteins was optomotor-blind protein in relation to wing development in the niacin-deficient medfly larvae.