scholarly journals Nuclear Magnetic Resonance Characterizes Metabolic Differences in Cymbopogon Schoenanthus Subsp. Proximus Embryogenic and Organogenic Calli and their Regenerated Shoots

2021 ◽  
Author(s):  
Asmaa Abdelsalam ◽  
Kamal Chowdhury ◽  
Arezue Boroujerdi ◽  
Ahmed El-Bakry
Keyword(s):  
Amino Acids ◽  
Nuclear Magnetic Resonance ◽  
Somatic Embryogenesis ◽  
Magnetic Resonance ◽  
Folk Medicine ◽  
Pharmacological Properties ◽  
Embryogenic Calli ◽  
Nmr Data ◽  
Polar Extracts ◽  
Cymbopogon Schoenanthus

Abstract Cymbopogon schoenanthus subsp. proximus is a threatened wild grass well known for its folk medicine uses and possesses a broad spectrum of pharmacological properties. In this study, the metabolite differences between embryogenic and organogenic calli have been characterized. Changes in the metabolome of somatic embryogenesis and organogenesis have been studied by comparing the metabolites of morphogenic calli with their respective regenerated shoots. Based on 1H and HSQC NMR data of the polar extracts, a total of 51 metabolites have been identified. Statistical analyses were performed to visualize the pattern of metabolites distribution among the studied groups. Glycolate present in organogenic calli, but not in organogenic calli. Some metabolites like glucose-6-phosphate, 4-aminobutyrate and arginine showed elevated concentrations in embryogenic calli than organogenic calli. While sucrose and myo-inositol up regulated in organogenic calli than embryogenic calli. Metabolites that marked embryogenic shoots from embryogenic calli have been described. Quantitatively, embryogenic shoots showed higher concentrations of sucrose, some amino acids, and trigonelline compared with embryogenic calli. In contrast, glucose, fructose, and arginine accumulated in embryogenic calli more than in embryogenic shoots. Likewise, metabolites characterized organogenic shoots from organogenic calli have been identified. Sucrose, several amino acids and trigonelline were detected in higher concentrations in organogenic shoots than in organogenic calli while monosaccharides and arginine accumulated in organogenic calli than in organogenic shoots. This study represents a first step towards understanding the metabolic activity of calli and shoots regenerated through different morphogenetic pathways.

scholarly journals Carbon 13 Nuclear Magnetic Resonance of Pentapeptides of Glycine Containing Central Residues of Aliphatic Amino Acids

1973 ◽  
Vol 248 (17) ◽  
pp. 6104-6113 ◽  
Author(s):  
Philip Keim ◽  
Robert A. Vigna ◽  
Robert C. Marshall ◽  
Frank R.N. Gurd
Keyword(s):  
Amino Acids ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nuclear Magnetic

scholarly journals High-resolution multidimensional parametric estimation for nuclear magnetic resonance spectroscopy

2021 ◽  
Author(s):  
◽  
Muhammad Ali Raza Anjum
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Magnetic Resonance Spectroscopy ◽  
Unbiased Estimator ◽  
Resonance Spectroscopy ◽  
Spectral Parameters ◽  
Nmr Data ◽  
Analytic Expressions ◽  
Nmr Signals

<p>Nuclear Magnetic Resonance spectroscopy (NMR) is a powerful technique for rapid and efficient quantitation of compounds in chemical samples. NMR causes the nuclei in the molecules to resonate and various chemical arrangements appear as peaks in the Fourier spectrum of a free induction decay (FID). The spectral parameters elicited from the peaks serve as a fingerprint of the chemical components contained in the molecule. These fingerprints can be employed to understand the chemical structure.  Signal acquired from a NMR spectrometer is ideally modelled as a superposition of multiple damped complex exponentials (cisoids) in Additive White Gaussian Noise (AWGN). The number as well as the spectral parameters of the cisoids need to be estimated for characterisation of the underlying chemicals. The estimation, however, suffers from numerous difficulties in practice. These include: unknown number of cisoids, large signal length, large dynamic range, large peak density, and numerous distortions caused by experimental artefacts.  This thesis aims at the development of estimators that, in view of the above-mentioned practical features, are capable of rapid, high-resolution and apriori-information-free quantitation of NMR signals. Moreover, for the analytic evaluation of the performance of such estimators, the thesis aims to derive interpretable analytic results for the fundamental estimation theory tool for assessing the performance of an unbiased estimator: the Cramer Rao Lower Bound (CRLB). By such results, we mean those that analytically allow the determination, in terms of the CRLB, of the impact of the free model parameters on the estimator performance.  For the CRLB, we report analytic expressions on the variance of unbiased parameter estimates of damping factors, frequencies and complex amplitudes of an arbitrary number of damped cisoids embedded in AWGN. In addition to the CRLB, analytic expressions for the determinant and the condition number of the associated Fisher Information Matrix (FIM) are also reported. Further results, in similar order, are reported for two special cases of the damped cisosid model: the Magnetic Resonance Relaxometry model and the amplitude-only model (employed in quantitative NMR - qNMR). Some auxiliary results for the above-mentioned models are also presented, i.e., on the multiplicity of the eigenvalues and the factorisation of the characteristic polynomial associated with their respective FIMs.  These results have not been previously reported. The reported theoretical results successfully account for various physical and chemical phenomena observed in experimental NMR data, and quantify their impact on the accuracy of an unbiased estimator as a function of both model and experimental parameters, e.g., influence of prior knowledge, peak multiplicity, multiplet symmetry, solvent peak, carbon satellites, etc.  For rapid, high-resolution and apriori-information-free quantitation of NMR signals, a sub-band Steiglitz-McBride algorithm is reported. The developed algorithm directly converts the time-domain FID data into a table of estimated amplitudes, phases, frequencies and damping factors, without requiring any previous knowledge or pre-processing. A 2D sub-band Steiglitz-McBride algorithm, for the quantitation of 2D NMR data in a similar manner, is also reported. The performance of the developed algorithms is validated by their application to experimental data, which manifests that they outperform the state-of-the-art in terms of speed, resolution and apriori-information-free operation.</p>

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