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Sample records for 1h-nmr 13c-nmr ms

  1. 1H-NMR and 13C-NMR lipid profiles of human renal tissues.

    PubMed

    Tugnoli, V; Bottura, G; Fini, G; Reggiani, A; Tinti, A; Trinchero, A; Tosi, M R

    2003-01-01

    Lipids from human renal tissues are studied by means of (1)H- and (13)C-NMR spectroscopy. The total lipid fractions obtained from healthy kidneys, malignant renal cell carcinomas, and benign oncocytomas are characterized and analyzed to elucidate the main differences between the functional and neoplastic tissues. In all cases the lipid components are well identified. The healthy kidney is characterized by high amounts of triglycerides and the presence of cholesterol in its free form. On the contrary, renal cell carcinomas contain high amounts of cholesterol that are almost completely esterified as oleate, suggesting an intracellular localization of the cholesteryl esters synthesis. Cholesteryl esters are considered markers of renal cell carcinomas, thus supporting recent theories that these compounds play a leading role in cell proliferation. Oncocytomas are particularly rich in phosphatidylcholine and, analogous to the healthy kidney, are completely lacking in cholesteryl esters. Healthy kidneys and oncocytomas appear to have other similarities if compared with renal cell carcinomas: a very high fatty acyl/cholesterol ratio, the presence of dolichols, and a higher grade of unsaturation. The (13)C data suggest a new method for the direct evaluation of the saturated/unsaturated fatty acyl ratio.

  2. Discovering [superscript 13]C NMR, [superscript 1]H NMR, and IR Spectroscopy in the General Chemistry Laboratory through a Sequence of Guided-Inquiry Exercises

    ERIC Educational Resources Information Center

    Iler, H. Darrell; Justice, David; Brauer, Shari; Landis, Amanda

    2012-01-01

    This sequence of three guided-inquiry labs is designed for a second-semester general chemistry course and challenges students to discover basic theoretical principles associated with [superscript 13]C NMR, [superscript 1]H NMR, and IR spectroscopy. Students learn to identify and explain basic concepts of magnetic resonance and vibrational…

  3. 1H NMR, 13C NMR and mass spectral studies of some Schiff bases derived from 3-amino-1,2,4-triazole.

    PubMed

    Issa, Y M; Hassib, H B; Abdelaal, H E

    2009-11-01

    Heterocyclic Schiff bases derived from 3-amino-1,2,4-triazole and different substituted aromatic aldehydes are prepared and subjected to (1)H NMR, (13)C NMR and mass spectral analyses. (1)H NMR spectra in DMSO exhibit a sharp singlet within the 9.35-8.90ppm region which corresponds to the azomethine proton. The position of this signal is largely dependent on the nature of the substituents on the benzal moiety. It is observed that the shape, position and the integration value of the signal of the aromatic proton of the triazole ring ((5)C) are clearly affected by the rate of exchange, relaxation time, concentration of solution as well as the solvent used. (13)C NMR is taken as substantial support for the results reached from (1)H NMR studies. The mass spectral results are taken as a tool to confirm the structure of the investigated compounds. The base peak (100%), mostly the M-1 peak, indicates the facile loss of hydrogen radical. The fragmentation pattern of the unsubstituted Schiff base is taken as the general scheme. Differences in the other schemes result from the effect of the electronegativity of the substituents attached to the aromatic ring.

  4. A new salen base 5-(phenylazo)-N-(2-amino pyridine) salicyliden Schiff base ligand: synthesis, experimental and density functional studies on its crystal structure, FTIR, 1H NMR and 13C NMR spectra.

    PubMed

    Sheikhshoaie, Iran; Saheb, Vahid

    2010-12-01

    A novel Schiff base ligand 5-(phenylazo)-N-(2-amino pyridine) salicyliden is prepared through the condensation of 5-(phenylazo) salicylaldehyde and 2-amino pyridine in methanol at room temperature. The orange crystalline precipitate is used for X-ray crystallography and measuring Fourier transform (FTIR), 1H NMR and 13C NMR spectra. Density functional theory (DFT) calculations at the B3LYP, MPWB1K and B3PW91 levels of theory is used to optimize the geometry and calculate the FTIR, 1H NMR and 13C NMR spectra of the compound. The vibrational frequencies determined experimentally are compared with those obtained theoretically and a vibrational assignment and analysis of the fundamental modes of the compound is performed. We found that the MPWB1K method predicts low vibrational frequencies better than the commonly used B3LYP method. Although the B3PW91 method overestimates the 1H NMR chemical shifts, the values computed at the B3LYP level of theory are in accordance with experimental 1H NMR spectrum. However, both B3LYP and B3PW91 methods tend to overestimate 13C NMR chemical shifts. In addition, a few quantum descriptors of the molecule are calculated and conformational analysis is performed and the result was compared with crystallographic data.

  5. A new Schiff base compound N,N'-(2,2-dimetylpropane)-bis(dihydroxylacetophenone): synthesis, experimental and theoretical studies on its crystal structure, FTIR, UV-visible, 1H NMR and 13C NMR spectra.

    PubMed

    Saheb, Vahid; Sheikhshoaie, Iran

    2011-10-15

    The Schiff base compound, N,N'-(2,2-dimetylpropane)-bis(dihydroxylacetophenone) (NDHA) is synthesized through the condensation of 2-hydroxylacetophenone and 2,2-dimethyl 1,3-amino propane in methanol at ambient temperature. The yellow crystalline precipitate is used for X-ray single-crystal determination and measuring Fourier transform infrared (FTIR), UV-visible, (1)H NMR and (13)C NMR spectra. Electronic structure calculations at the B3LYP, PBEPBE and PW91PW91 levels of theory are performed to optimize the molecular geometry and to calculate the FTIR, (1)H NMR and (13)C NMR spectra of the compound. Time-dependent density functional theory (TDDFT) method is used to calculate the UV-visible spectrum of NDHA. Vibrational frequencies are determined experimentally and compared with those obtained theoretically. Vibrational assignments and analysis of the fundamental modes of the compound are also performed. All theoretical methods can well reproduce the structure of the compound. The (1)H NMR and (13)C NMR chemical shifts calculated by all DFT methods are consistent with the experimental data. However, the NMR shielding tensors computed at the B3LYP/6-31+G(d,p) level of theory are in better agreement with experimental (1)H NMR and (13)C NMR spectra. The electronic absorption spectrum calculated at the B3LYP/6-31+G(d,p) level by using TD-DFT method is in accordance with the observed UV-visible spectrum of NDHA. In addition, some quantum descriptors of the molecule are calculated and conformational analysis is performed and the results were compared with the crystallographic data.

  6. Combined experimental and theoretical studies on the X-ray crystal structure, FT-IR, 1H NMR, 13C NMR, UV-Vis spectra, NLO behavior and antimicrobial activity of 2-hydroxyacetophenone benzoylhydrazone.

    PubMed

    Sheikhshoaie, Iran; Ebrahimipour, S Yousef; Sheikhshoaie, Mahdeyeh; Rudbari, Hadi Amiri; Khaleghi, Moj; Bruno, Giuseppe

    2014-04-24

    A Schiff base ligand, 2-hydroxyacetophenone benzoylhydrazone (HL) was synthesized and fully characterized with FT-IR, elemental analyses, UV-Vis, (1)H NMR and (13)C NMR spectra. DFT calculations using B3LYP/6-31+G(d,p) and PW91/DZP are performed to optimize the molecular geometry. Optimized structures are used to calculate FT-IR, UV-Vis, (1)H NMR and (13)C NMR spectra of the compound. Also the energies of the frontier molecular orbitals (FMOs) have been determined. The results obtained from the optimization and spectral analyses are in good agreement with the experimental data. To investigate non-linear optical properties, the electric dipole moment (μ), polarizability (α) and molecular first hyperpolarizability (β) were computed. The linear polarizabilities and first hyperpolarizabilities of the studied molecule indicate that the compound can be a good candidate of nonlinear optical materials. In addition, the minimal inhibitory concentration (MIC) of this compound against Staphylococcus aureus, and Candida albicans was determined.

  7. Structural determination of Zn and Cd-DTPA complexes: MS, infrared, (13)C NMR and theoretical investigation.

    PubMed

    Silva, Vanézia L; Carvalho, Ruy; Freitas, Matheus P; Tormena, Cláudio F; Melo, Walclée C

    2007-12-31

    The joint application of MS, infrared and (13)C NMR techniques for the determination of metal-DTPA structures (metal=Zn and Cd; DTPA=diethylenetriaminepentacetic acid) is reported. Mass spectrometry allowed determining the 1:1 stoichiometry of the complexes, while infrared analysis suggested that both nitrogen and carboxyl groups are sites for complexation. The (13)C NMR spectrum for the cadmium-containing complex evidenced the existence of free and complexed carboxyl groups, due to a straight singlet at 179.0 ppm (free carboxylic (13)C) and to two broad singlets or a broad doublet at 178.3 ppm (complexed carboxylic (13)C, (2)J(Cd-C(=O))=45.2 Hz). A similar interpretation might be given for the zinc derivative and, with the aid of DFT calculations, structures for both complexes were then proposed.

  8. Solution behavior and complete sup 1 H and sup 13 C NMR assignments of the coenzyme B sub 12 derivative (5 prime -deoxyadenosyl)cobinamide using modern 2D NMR experiments, including 600-MHz sup 1 H NMR data

    SciTech Connect

    Pagano, T.G.; Yohannes, P.G.; Marzilli, L.G. ); Hay, B.P.; Scott, J.R.; Finke, R.G. )

    1989-02-15

    Two-dimensional (2D) NMR methods have been used to assign completely the {sup 1}H and {sup 13}C NMR spectra of the (5{prime}-deoxyadenosyl)cobinamide cation (AdoCbi{sup +}) in D{sub 2}O. Most of the {sup 1}H spectral assignments were made by using 2D homonuclear shift correlation spectroscopy (COSY), homonuclear Hartmann-Hahn spectroscopy (HOHAHA), absorption-mode (phase sensitive) 2D nuclear Overhauser effect (NOE) spectroscopy, and spin-locked NOE spectroscopy (also called ROESY, for rotating-frame Overhauser enhancement spectroscopy). Most of the protonated carbon resonances were assigned by using {sup 1}H-detected heteronuclear multiple-quantum coherence (HMQC) spectroscopy. The nonprotonated carbon resonances, as well as the remaining unassigned {sup 1}H and {sup 13}C NMR signals, were assigned from long-range {sup 1}H-{sup 13}C connectivities determined from {sup 1}H-detected multiple-bond heteronuclear multiple-quantum coherence spectroscopy (HMBC). Comparison of the {sup 13}C chemical shifts and {sup 1}H NOEs of AdoCbi{sup +} with those of coenzyme B{sup 12} ((5{prime}-deoxyadenosyl)cobalamin) and its benzimidazole-protonated, base-off form indicates that the electronic properties and structure of AdoCbi{sup +} are similar to that of coenzyme B{sup 12} in the protonated, base-off form. The {sup 13}C chemical shifts of most of the carbons of AdoCbi{sup +} do not vary significantly from those of base-off, benzimidazole-protonated coenzyme B{sup 12}, indicating that the electronic environment of the corrin ring is also similar in both compounds. However, significant differences in the chemical shifts of some of the corresponding carbons of the b, d, e, and f corrin side chains in AdoCbi{sup +} and in base-off, benzimidazole-protonated coenzyme B{sub 12} indicate that the positions of these side chains may be different in AdoCbi{sup +} compared to base-off coenzyme B{sup 12}.

  9. Chemical composition of the essential oil from Corsican Mentha aquatica--combined analysis by GC(RI), GC-MS and 13C NMR spectroscopy.

    PubMed

    Sutour, Sylvain; Tomi, Félix; Bradesi, Pascale; Casanova, Joseph

    2011-10-01

    The essential oil (EO) of M. aquatica L. growing wild in Corsica was isolated by dry vapor distillation and submitted to combined analysis by column chromatography over silica gel, GC(RI), GC-MS and 13C NMR spectroscopy. The composition was dominated byoxygenated monoterpenes and characterized by the occurrence of menthofuran (50.7%) as the major component. In parallel, seven laboratory-distilled oil samples isolated from individual plants collected in Corsica were analyzed by GC(RI) and 13C NMR spectroscopy. Onlyquantitative differences were observed between the samples. Beside the usual terpenes, various p-menthane lactones (mintlactone, isomintlactone, hydroxymintlactone, menthofurolactone and epimenthofurolactone) have been identified in all the oil samples.

  10. Combined analysis by GC (RI), GC-MS and 13C NMR of the supercritical fluid extract of Abies alba twigs.

    PubMed

    Duquesnoy, Emilie; Marongiu, Bruno; Castola, Vincent; Piras, Alessandra; Porcedda, Silvia; Casanova, Joseph

    2010-12-01

    Two samples (leaves and twigs) of Abies alba Miller from Corsica were extracted using supercritical CO2 and their chemical compositions were compared with those of the essential oils obtained from the same batch of plant material. In total 45 components were identified using combined analysis by GC (RI), GC-MS and 13C NMR. It was observed that the contents of monoterpenes (mainly represented by limonene, alpha-pinene and camphene) were significantly lower in the supercritical fluid extract (SFE) than in the essential oil (EO). Conversely, the proportions of sesquiterpenes were much higher in CO2 extracts than in essential oils (around 30% vs 4%). Cis-abienol, a diterpene alcohol, was identified only in SFE, and the proportions of this constituent (7.5% and 17.3%) were determined using quantitative 13C NMR since it was under estimated using the standard conditions of GC.

  11. LC-MS and 1H NMR as an improved dereplication tool to identify antifungal diterpenoids from Sagittaria latifolia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A dereplication strategy using a combination of liquid chromatography-mass spectrometry (LC-MS) and proton nuclear magnetic resonance spectroscopy (1H NMR) to facilitate compound identification towards antifungal natural product discovery is presented. This analytical approach takes advantage of th...

  12. Composition and chemical variability of the leaf oil from Corsican Juniperus thurifera. Integrated analysis by GC(RI), GC-MS and 13C NMR.

    PubMed

    Ottavioli, Josephine; Casanova, Joseph; Bighelli, Ange

    2010-12-01

    The composition of 16 samples of leaf oil from Corsican Juniperus thurifera was investigated by integrated techniques, GC, GC-MS and 13C NMR. K-means partitioning and PCA analysis of the data allowed the definition of a main group (14 samples) dominated by limonene (mean = 52.2%, SD = 6.4) and alpha-pinene (mean = 7.2%, SD = 3.8). Limonene and beta-elemol (up to 19.7%) were identified as the major components of two atypic samples.

  13. Unambiguous Metabolite Identification in High-Throughput Metabolomics by Hybrid 1H-NMR/ESI-MS1 Approach

    SciTech Connect

    2016-10-18

    The invention improves accuracy of metabolite identification by combining direct infusion ESI-MS with one-dimensional 1H-NMR spectroscopy. First, we apply a standard 1H-NMR metabolite identification protocol by matching the chemical shift, J-coupling and intensity information of experimental NMR signals against the NMR signals of standard metabolites in a metabolomics reference libraries. This generates a list of candidate metabolites. The list contains both false positive and ambiguous identifications. The software tool (the invention) takes the list of candidate metabolites, generated from NMRbased metabolite identification, and then calculates, for each of the candidate metabolites, the monoisotopic mass-tocharge (m/z) ratios for each commonly observed ion, fragment and adduct feature. These are then used to assign m/z ratios in experimental ESI-MS spectra of the same sample. Detection of the signals of a given metabolite in both NMR and MS spectra resolves the ambiguities, and therefore, significantly improves the confidence of the identification.

  14. LC-MS- and (1)H NMR Spectroscopy-Guided Identification of Antifungal Diterpenoids from Sagittaria latifolia.

    PubMed

    Ravu, Ranga Rao; Jacob, Melissa R; Jeffries, Cynthia; Tu, Ying; Khan, Shabana I; Agarwal, Ameeta K; Guy, R Kiplin; Walker, Larry A; Clark, Alice M; Li, Xing-Cong

    2015-09-25

    Antifungal screening of small-molecule natural product libraries showed that a column fraction (CF) derived from the plant extract of Sagittaria latifolia was active against the fungal pathogen Cryptococcus neoformans. Dereplication analysis by liquid chromatography-mass spectrometry (LC-MS) and proton nuclear magnetic resonance spectroscopy ((1)H NMR) indicated the presence of new compounds in this CF. Subsequent fractionation of the plant extract resulted in the identification of two new isopimaradiene-type diterpenoids, 1 and 2. The structures of 1 and 2 were determined by chemical methods and spectroscopic analysis as isopimara-7,15-dien-19-ol 19-O-α-l-arabinofuranoside and isopimara-7,15-dien-19-ol 19-O-α-l-(5'-acetoxy)arabinofuranoside, respectively. Compound 1 exhibited IC50 values of 3.7 and 1.8 μg/mL, respectively, against C. neoformans and C. gattii. Its aglycone, isopimara-7,15-dien-19-ol (3), resulting from acid hydrolysis of 1, was also active against the two fungal pathogens, with IC50 values of 9.2 and 6.8 μg/mL, respectively. This study demonstrates that utilization of the combined LC-MS and (1)H NMR analytical tools is an improved chemical screening approach for hit prioritization in natural product drug discovery.

  15. (1)H NMR and GC-MS based metabolomics reveal nano-Cu altered cucumber (Cucumis sativus) fruit nutritional supply.

    PubMed

    Zhao, Lijuan; Hu, Jerry; Huang, Yuxiong; Wang, Hongtao; Adeleye, Adeyemi; Ortiz, Cruz; Keller, Arturo A

    2017-01-01

    It is imperative to study the interaction of nanoparticles residuals with crop plants in agricultural soils, due to the increased application of nanotechnology in agriculture. So far, a few studies have focused on the impact of nanoparticles on fruit quality and nutritional supply. In this work, a thorough and comprehensive analysis of metabolite changes of cucumber fruits from plants under nano-Cu stress was possible through the use of both (1)H NMR and GC-MS. The results of supervised partial least-squares discriminant analysis from both platforms showed that cucumber fruit extracts samples were clearly grouped based on the nano-Cu level in soil. This indicates that the fruit metabolite profile was influenced by exposure to nano-Cu. GC-MS data showed concentrations of some sugars, organic acids, amino acids, and fatty acids were increased or decreased by nano-Cu. Several metabolites, such as methylnicotinamide (MNA), trigonelline, imidazole, quinolinate were only detected and quantified by (1)H NMR. Our results showed that combining the two platforms provided a comprehensive understanding about the metabolites (nutrient supply) changes in cucumber fruits impacted by exposure to nano-Cu.

  16. Development of a stability-indicating HPLC method of etifoxine with characterization of degradation products by LC-MS/TOF, 1H and 13C NMR.

    PubMed

    Djabrouhou, Nadia; Guermouche, Moulay-Hassane

    2014-11-01

    This paper describes a new LC-MS/TOF method for the degradation products determination when Etifoxine (ETI) is submitted to different stress conditions. Chromatography is performed by using Kromasil C18 column (250mm×4.6mm, 5μm particle size). The selected mobile phase consists of formate buffer 0.02M, pH 3 and methanol (70/30, v/v). ETI is submitted to oxidative, acidic, basic, hydrolytic, thermal and UV light degradations. Detection is made at 254nm by photodiode array detector and mass spectrometry. A number of degradation products (DPs) called DPA, DPB, DPC and DPD are found depending on the stress; DPA with heat, DPA and DPB in acidic media or under UV-light; DPA, DPB and DPC under basic stress; DPA, DPB, DPC and DPD with oxidation. LC-MS/TOF is used to characterize the four DPs of ETI resulting from different stress conditions. (1)H and (13)C NMR are used to confirm the DP structures. The ETI fragmentation pathway is proposed. The method is validated with reference to International Conference on Harmonization guidelines and ETI are selectively determined in presence of its DPs, demonstrating its stability-indicating nature. Finally, for the validation step, specificity, linearity, accuracy and precision are determined for ETI and its DPs.

  17. Metabolic fingerprinting of Leontopodium species (Asteraceae) by means of 1H NMR and HPLC–ESI-MS

    PubMed Central

    Safer, Stefan; Cicek, Serhat S.; Pieri, Valerio; Schwaiger, Stefan; Schneider, Peter; Wissemann, Volker; Stuppner, Hermann

    2011-01-01

    The genus Leontopodium, mainly distributed in Central and Eastern Asia, consists of ca. 34–58 different species. The European Leontopodium alpinum, commonly known as Edelweiss, has a long tradition in folk medicine. Recent research has resulted in the identification of prior unknown secondary metabolites, some of them with interesting biological activities. Despite this, nearly nothing is known about the Asian species of the genus. In this study, we applied proton nuclear magnetic resonance (1H NMR) spectroscopy and liquid chromatography–mass spectrometry (LC–MS) metabolic fingerprinting to reveal insights into the metabolic patterns of 11 different Leontopodium species, and to conclude on their taxonomic relationship. Principal component analysis (PCA) of 1H NMR fingerprints revealed two species groups. Discriminators for these groups were identified as fatty acids and sucrose for group A, and ent-kaurenoic acid and derivatives thereof for group B. Five diterpenes together with one sesquiterpene were isolated from Leontopodium franchetii roots; the compounds were described for the first time for L. franchetii: ent-kaur-16-en-19-oic acid, methyl-15α-angeloyloxy-ent-kaur-16-en-19-oate, methyl-ent-kaur-16-en-19-oate, 8-acetoxymodhephene, 19-acetoxy-ent-kaur-16-ene, methyl-15β–angeloyloxy-16,17-epoxy-ent-kauran-19-oate. In addition, differences in the metabolic profile between collected and cultivated species could be observed using a partial least squares-discriminant analysis (PLS-DA). PCA of the LC–MS fingerprints revealed three groups. Discriminating signals were compared to literature data and identified as two bisabolane derivatives responsible for discrimination of group A and C, and one ent-kaurenoic acid derivative, discriminating group B. A taxonomic relationship between a previously unidentified species and L. franchetii and Leontopodium sinense could be determined by comparing NMR fingerprints. This finding supports recent molecular data

  18. Combined analysis of the essential oil of Chenopodium ambrosioides by GC, GC-MS and 13C-NMR spectroscopy: quantitative determination of ascaridole, a heat-sensitive compound.

    PubMed

    Cavalli, Jean-François; Tomi, Félix; Bernardini, Antoine-François; Casanova, Joseph

    2004-01-01

    A commercial sample of the essential oil of Chenopodium ambrosioides L. from Madagascar was analysed by GC, GC-MS and 13C-NMR. By GC analysis, the major constituents were found to be ascaridole (1) (41.8%), isoascaridole (2) (18.1%), p-cymene (16.2%), alpha-terpinene (9.7%) and limonene (3.8%). However, ascaridole undergoes a partial thermal isomerisation to 2 and hence the amount of 1 is under-estimated by GC analysis. The actual contents of 1 and 2 (55.3 and 4.6%, respectively) were obtained following combined analysis of the sample by GC and 13C-NMR. Several hydroxy- and polyhydroxy-menthanes were identified by 13C-NMR.

  19. Identification of isomeric dicaffeoylquinic acids from Eleutherococcus senticosus using HPLC-ESI/TOF/MS and 1H-NMR methods.

    PubMed

    Tolonen, Ari; Joutsamo, Topi; Mattlla, Sampo; Kämäräinen, Terttu; Jalonen, Jorma

    2002-01-01

    Liquid chromatography-electrospray time-of-flight mass spectrometry (HPLC-ESI/TOF/MS) and a novel NMR technique, developed to maximise the sensitivity obtained from the standard NMR spectrometer, have been applied to the identification of the phenolic constituents of Eleutherococcus senticosus. In addition, molecular modelling and dihedral bond angle calculations based on the vicinal 3JHH-coupling constants have been used in the unambiguous assignment of signals in the 1H-NMR spectra. 5'-O-Caffeoylquinic acid and three isomeric compounds, 1',5'-O-dicaffeoylquinic acid, 3',5'-O-dicaffeoylquinic acid and 4',5'-O-dicaffeoylquinic acid, have been isolated and identified from a sample. The isolation and structure determination of the latter two compounds are reported for the first time from this plant.

  20. Metabolomic Characterization of Nipple Aspirate Fluid by 1H NMR Spectroscopy and GC-MS

    PubMed Central

    Tredwell, Gregory D.; Miller, Jessica A.; Chow, H.-H. Sherry; Thompson, Patricia A.; Keun, Hector C.

    2015-01-01

    Nipple aspirate fluid (NAF) is a noninvasively obtained biofluid from the duct openings of the breast. NAF components are constantly secreted, metabolized, and reabsorbed by the epithelial lining of the lactiferous ducts of the breast. NAF has been studied as a potential breast tissue surrogate for the discovery of novel breast cancer risk, early detection, and treatment response biomarkers. We report the first unsupervised metabolite characterization of nipple aspirate fluid using NMR and GC-MS using convenience samples previously collected from four premenopausal and four postmenopausal women. A total of 38 metabolites were identified using the two analytical techniques, including amino acids, organic acids, fatty acids, and carbohydrates. Analytical reproducibility of metabolites in NAF by GC-MS was high across different extraction and analysis days. Overall, 31 metabolites had a coefficient of variation below 20%. By GC-MS, there were eight metabolites unique to NAF, 19 unique to plasma, and 24 shared metabolites. Correlative analysis of shared metabolites between matched NAF and plasma samples from pre- and postmenopausal women shows almost no correlations, with the exception being lactic acid, which was significantly negatively correlated (R2 = 0.57; P = 0.03). These results suggest that NAF is metabolically distinct from plasma and that the application of metabolomic strategies may be useful for future studies investigating breast cancer risk and intervention response biomarkers. PMID:24364541

  1. Degradation Kinetics and Mechanism of Lithospermic Acid under Low Oxygen Condition Using Quantitative 1H NMR with HPLC-MS

    PubMed Central

    Pan, Jianyang; Gong, Xingchu; Qu, Haibin

    2016-01-01

    A novel quantitative 1H NMR (Q-NMR) combined with HPLC-MS method has been proposed for investigating the degradation process of traditional Chinese medicine (TCM) components. Through this method, in-situ monitoring of dynamics degradation process of lithospermic acid (LA), one of the popular polyphenolic acids in TCM, was realized under low oxygen condition. Additionally, this methodology was proved to be simple, rapid and specific. Degradation kinetic runs have been carried out to systematically investigate the effects of two key environmental factors, initial pH values and temperatures. Eight main degradation products of LA were detected, seven of which were tentatively structural elucidated with the help of both NMR and LC-MS in this work and salvianolic acid A (Sal A) was the primary degradation product of LA. A possible degradation pathway of LA was proposed, subsequently. The results showed that the degradation of LA followed pseudo-first-order kinetics. The apparent degradation kinetic constants increased as the initial pH value of the phosphate buffer increased. Under the given conditions, the rate constants of overall degradation as a function of temperature obeyed the Arrhenius equation. Our results proved that the Q-NMR combined with HPLC-MS method can be one of the most promising techniques for investigating degradation process of active components in TCM. PMID:27776128

  2. Molecular structure, spectral investigation (1H NMR, 13C NMR, UV-Visible, FT-IR, FT-Raman), NBO, intramolecular hydrogen bonding, chemical reactivity and first hyperpolarizability analysis of formononetin [7-hydroxy-3(4-methoxyphenyl)chromone]: A quantum chemical study

    NASA Astrophysics Data System (ADS)

    Srivastava, Anubha; Mishra, Rashmi; Kumar, Sudhir; Dev, Kapil; Tandon, Poonam; Maurya, Rakesh

    2015-03-01

    Formononetin [7-hydroxy-3(4-methoxyphenyl)chromone or 4‧-methoxy daidzein] is a soy isoflavonoid that is found abundantly in traditional Chinese medicine Astragalus mongholicus (Bunge) and Trifolium pretense L. (red clover), and in an Indian medicinal plant, Butea (B.) monosperma. Crude extract of B.monosperma is used for rapid healing of fracture in Indian traditional medicine. In this study, a combined theoretical and experimental approach is used to study the properties of formononetin. The optimized geometry was calculated by B3LYP method using 6-311++G(d,p) as a large basis set. The FT-Raman and FT-IR spectra were recorded in the solid phase, and interpreted in terms of potential energy distribution (PED) analysis. Density functional theory (DFT) is applied to explore the nonlinear optical properties of the molecule. Good consistency is found between the calculated results and observed data for the electronic absorption, IR and Raman spectra. The solvent effects have been calculated using time-dependent density functional theory in combination with the integral equation formalism polarized continuum model, and the results are in good agreement with observed measurements. The double well potential energy curve of the molecule about the respective bonds, have been plotted, as obtained from DFT/6-31G basis set. The computational results diagnose the most stable conformer of formononetin. The HOMO-LUMO energy gap of possible conformers has been calculated for comparing their chemical activity. Chemical reactivity has been measured by reactivity descriptors and molecular electrostatic potential surface (MEP). The 1H and 13C NMR chemical shifts of the molecule were calculated by the Gauge including atomic orbital (GIAO) method. Furthermore, the role of CHsbnd O intramolecular hydrogen bond in the stability of molecule is investigated on the basis of the results of topological properties of AIM theory and NBO analysis. The calculated first hyperpolarizability shows

  3. Classification of Coffee Beans by GC-C-IRMS, GC-MS, and 1H-NMR

    PubMed Central

    Arana, Victoria Andrea; Esseiva, Pierre; Pazos, Diego

    2016-01-01

    In a previous work using 1H-NMR we reported encouraging steps towards the construction of a robust expert system for the discrimination of coffees from Colombia versus nearby countries (Brazil and Peru), to assist the recent protected geographical indication granted to Colombian coffee in 2007. This system relies on fingerprints acquired on a 400 MHz magnet and is thus well suited for small scale random screening of samples obtained at resellers or coffee shops. However, this approach cannot easily be implemented at harbour's installations, due to the elevated operational costs of cryogenic magnets. This limitation implies shipping the samples to the NMR laboratory, making the overall approach slower and thereby more expensive and less attractive for large scale screening at harbours. In this work, we report on our attempt to obtain comparable classification results using alternative techniques that have been reported promising as an alternative to NMR: GC-MS and GC-C-IRMS. Although statistically significant information could be obtained by all three methods, the results show that the quality of the classifiers depends mainly on the number of variables included in the analysis; hence NMR provides an advantage since more molecules are detected to obtain a model with better predictions. PMID:27516919

  4. Urinary (1)H-NMR and GC-MS metabolomics predicts early and late onset neonatal sepsis.

    PubMed

    Fanos, Vassilios; Caboni, Pierluigi; Corsello, Giovanni; Stronati, Mauro; Gazzolo, Diego; Noto, Antonio; Lussu, Milena; Dessì, Angelica; Giuffrè, Mario; Lacerenza, Serafina; Serraino, Francesca; Garofoli, Francesca; Serpero, Laura Domenica; Liori, Barbara; Carboni, Roberta; Atzori, Luigi

    2014-03-01

    The purpose of this article is to study one of the most significant causes of neonatal morbidity and mortality: neonatal sepsis. This pathology is due to a bacterial or fungal infection acquired during the perinatal period. Neonatal sepsis has been categorized into two groups: early onset if it occurs within 3-6 days and late onset after 4-7 days. Due to the not-specific clinical signs, along with the inaccuracy of available biomarkers, the diagnosis is still a major challenge. In this regard, the use of a combined approach based on both nuclear magnetic resonance ((1)H-NMR) and gas-chromatography-mass spectrometry (GC-MS) techniques, coupled with a multivariate statistical analysis, may help to uncover features of the disease that are still hidden. The objective of our study was to evaluate the capability of the metabolomics approach to identify a potential metabolic profile related to the neonatal septic condition. The study population included 25 neonates (15 males and 10 females): 9 (6 males and 3 females) patients had a diagnosis of sepsis and 16 were healthy controls (9 males and 7 females). This study showed a unique metabolic profile of the patients affected by sepsis compared to non-affected ones with a statistically significant difference between the two groups (p = 0.05).

  5. LC-MS- and (1)H NMR-Based Metabolomic Analysis and in Vitro Toxicological Assessment of 43 Aristolochia Species.

    PubMed

    Michl, Johanna; Kite, Geoffrey C; Wanke, Stefan; Zierau, Oliver; Vollmer, Guenter; Neinhuis, Christoph; Simmonds, Monique S J; Heinrich, Michael

    2016-01-22

    Species of Aristolochia are used as herbal medicines worldwide. They cause aristolochic acid nephropathy (AAN), a devastating disease associated with kidney failure and renal cancer. Aristolochic acids I and II (1 and 2) are considered to be responsible for these nephrotoxic and carcinogenic effects. A wide range of other aristolochic acid analogues (AAAs) exist, and their implication in AAN may have been overlooked. An LC-MS- and (1)H NMR-based metabolomic analysis was carried out on 43 medicinally used Aristolochia species. The cytotoxicity and genotoxicity of 28 Aristolochia extracts were measured in human kidney (HK-2) cells. Compounds 1 and 2 were found to be the most common AAAs. However, AA IV (3), aristolactam I (4), and aristolactam BI (5) were also widespread. No correlation was found between the amounts of 1 or 2 and extract cytotoxicity against HK-2 cells. The genotoxicity and cytotoxicity of the extracts could be linked to their contents of 5, AA D (8), and AA IIIa (10). These results undermine the assumption that 1 and 2 are exclusively responsible for the toxicity of Aristolochia species. Other analogues are likely to contribute to their toxicity and need to be considered as nephrotoxic agents. These findings facilitate understanding of the nephrotoxic mechanisms of Aristolochia and have significance for the regulation of herbal medicines.

  6. Metabolite and mineral profiling of "Violetto di Niscemi" and "Spinoso di Menfi" globe artichokes by (1)H-NMR and ICP-MS.

    PubMed

    Albergamo, Ambrogina; Rotondo, Archimede; Salvo, Andrea; Pellizzeri, Vito; Bua, Daniel G; Maggio, Antonella; Cicero, Nicola; Dugo, Giacomo

    2017-05-01

    Globe artichoke has been long considered a nutraceutical food for its valuable content of bioactive compounds. However, beside a well-known polyphenol profile, poor information is available about its metabolite and mineral composition. The aim of this study was to investigate edible parts of Sicilian artichokes, 'Spinoso di Menfi' and 'Violetto di Niscemi', by (1)H NMR and ICP-MS for elucidating these compositional aspects. Although bracts and hearts of both artichokes shared a very similar metabolite pattern, 'Spinoso di Menfi' showed a higher number of metabolites, such as amino acids and polyphenols, than 'Violetto di Niscemi'. 'Spinoso di Menfi' was also marked by higher levels of macro- and microelements when compared to 'Violetto di Niscemi'. Also, artichoke heart demonstrated to accumulate higher mineral levels than bracts. (1)H NMR and ICP-MS successfully profiled metabolites and metals in such plant food, partially covering the lack of literature data about 'Spinoso di Menfi' and 'Violetto di Niscemi' artichokes.

  7. An integrated analysis for determining the geographical origin of medicinal herbs using ICP-AES/ICP-MS and (1)H NMR analysis.

    PubMed

    Kwon, Yong-Kook; Bong, Yeon-Sik; Lee, Kwang-Sik; Hwang, Geum-Sook

    2014-10-15

    ICP-MS and (1)H NMR are commonly used to determine the geographical origin of food and crops. In this study, data from multielemental analysis performed by ICP-AES/ICP-MS and metabolomic data obtained from (1)H NMR were integrated to improve the reliability of determining the geographical origin of medicinal herbs. Astragalus membranaceus and Paeonia albiflora with different origins in Korea and China were analysed by (1)H NMR and ICP-AES/ICP-MS, and an integrated multivariate analysis was performed to characterise the differences between their origins. Four classification methods were applied: linear discriminant analysis (LDA), k-nearest neighbour classification (KNN), support vector machines (SVM), and partial least squares-discriminant analysis (PLS-DA). Results were compared using leave-one-out cross-validation and external validation. The integration of multielemental and metabolomic data was more suitable for determining geographical origin than the use of each individual data set alone. The integration of the two analytical techniques allowed diverse environmental factors such as climate and geology, to be considered. Our study suggests that an appropriate integration of different types of analytical data is useful for determining the geographical origin of food and crops with a high degree of reliability.

  8. Whole-core analysis by sup 13 C NMR

    SciTech Connect

    Vinegar, H.J.; Tutunjian, P.N. ); Edelstein, W.A.; Roemer, P.B. )

    1991-06-01

    This paper reports on a whole-core nuclear magnetic resonance (NMR) system that was used to obtain natural abundance {sup 13}C spectra. The system enables rapid, nondestructive measurements of bulk volume of movable oil, aliphatic/aromatic ratio, oil viscosity, and organic vs. carbonate carbon. {sup 13}C NMR can be used in cores where the {sup 1}H NMR spectrum is too broad to resolve oil and water resonances separately. A 5 1/4-in. {sup 13}C/{sup 1}H NMR coil was installed on a General Electric (GE) CSI-2T NMR imager/spectrometer. With a 4-in.-OD whole core, good {sup 13}C signal/noise ratio (SNR) is obtained within minutes, while {sup 1}H spectra are obtained in seconds. NMR measurements have been made of the {sup 13}C and {sup 1}H density of crude oils with a wide range of API gravities. For light- and medium-gravity oils, the {sup 13}C and {sup 1}H signal per unit volume is constant within about 3.5%. For heavy crudes, the {sup 13}C and {sup 1}H density measured by NMR is reduced by the shortening of spin-spin relaxation time. {sup 13}C and {sup 1}H NMR spin-lattice relaxation times were measured on a suite of Cannon viscosity standards, crude oils (4 to 60{degrees} API), and alkanes (C{sub 5} through C{sub 16}) with viscosities at 77{degrees}F ranging from 0.5 cp to 2.5 {times} 10{sup 7} cp. The {sup 13}C and {sup 1}H relaxation times show a similar correlation with viscosity from which oil viscosity can be estimated accurately for viscosities up to 100 cp. The {sup 13}C surface relaxation rate for oils on water-wet rocks is very low. Nonproton decoupled {sup 13}C NMR is shown to be insensitive to kerogen; thus, {sup 13}C NMR measures only the movable hydrocarbon content of the cores. In carbonates, the {sup 13}C spectrum also contains a carbonate powder pattern useful in quantifying inorganic carbon and distinguishing organic from carbonate carbon.

  9. Development and validation of a RP-HPLC method for stability-indicating assay of gemifloxacin mesylate including identification of related substances by LC-ESI-MS/MS, 1H and 13C NMR spectroscopy.

    PubMed

    Rao, R Nageswara; Naidu, Ch Gangu; Prasad, K Guru; Narasimha, R

    2011-11-01

    A validated stability indicating RP-HPLC assay of gemifloxacin mesylate was developed by separating its related substances on an Inertsil-ODS3V-C18 (4.6 × 250 mm; 5 μm) column using 0.1% trifluoroaceticacid (pH 2.5) and methanol as a mobile phase in a gradient elution mode at a flow rate of 1.0 mL/min at 27°C. The column effluents were monitored by a photodiode array detector set at 287 nm. The method was validated in terms of accuracy, precision and linearity as per ICH guidelines. Forced degradation of gemifloxacin (GFX) was carried out under acidic, basic, thermal, photolysis and peroxide conditions and the degradation products were separated and characterized by ESI-MS/MS, (1) H and (13) C NMR spectroscopy. The method was successfully applied to the analysis of bulk drugs and the recoveries of gemifloxacin and impurities were in the range of 97.60-102.90 and 96.99-102.10%, respectively. No previous reports were found in the literature on identification of degradation products of gemifloxacin.

  10. What the devil is in your phytomedicine? Exploring species substitution in Harpagophytum through chemometric modeling of 1H-NMR and UHPLC-MS datasets.

    PubMed

    Mncwangi, Nontobeko P; Viljoen, Alvaro M; Zhao, Jianping; Vermaak, Ilze; Chen, Wei; Khan, Ikhlas

    2014-10-01

    Harpagophytum procumbens (Pedaliaceae) and its close taxonomical ally Harpagophytum zeyheri, indigenous to southern Africa, are being harvested for exportation to Europe where phytomedicines are developed to treat inflammation-related disorders. The phytochemical variation within and between natural populations of H. procumbens (n=241) and H. zeyheri (n=107) was explored using proton nuclear magnetic resonance ((1)H-NMR) and ultra-high performance liquid chromatography coupled to mass spectrometry (UHPLC-MS) in combination with multivariate data analysis methods. The UHPLC-MS results revealed significant variation in the harpagoside content: H. procumbens (0.17-4.37%); H. zeyheri (0.00-3.07%). Only 41% of the H. procumbens samples and 17% of the H. zeyheri samples met the pharmacopoeial specification of ⩾1.2%. Both principal component analysis (PCA) and orthogonal projections to latent structures discriminant analysis (OPLS-DA) indicated separation based on species (UHPLC-MS data OPLS-DA model statistics: R(2)X=0.258, R(2)Y (cum)=0.957 and Q(2)(cum)=0.934; (1)H-NMR data OPLS-DA model statistics: R(2)X=0.830, R(2)Y=0.865 (cum) and Q(2)(cum)=0.829). It was concluded that two species are not chemically equivalent and should not be used interchangeably.

  11. (1)H NMR and GC-MS Based Metabolomics Reveal Defense and Detoxification Mechanism of Cucumber Plant under Nano-Cu Stress.

    PubMed

    Zhao, Lijuan; Huang, Yuxiong; Hu, Jerry; Zhou, Hongjun; Adeleye, Adeyemi S; Keller, Arturo A

    2016-02-16

    Because copper nanoparticles are being increasingly used in agriculture as pesticides, it is important to assess their potential implications for agriculture. Concerns have been raised about the bioaccumulation of nano-Cu and their toxicity to crop plants. Here, the response of cucumber plants in hydroponic culture at early development stages to two concentrations of nano-Cu (10 and 20 mg/L) was evaluated by proton nuclear magnetic resonance spectroscopy ((1)H NMR) and gas chromatography-mass spectrometry (GC-MS) based metabolomics. Changes in mineral nutrient metabolism induced by nano-Cu were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Results showed that nano-Cu at both concentrations interferes with the uptake of a number of micro- and macro-nutrients, such as Na, P, S, Mo, Zn, and Fe. Metabolomics data revealed that nano-Cu at both levels triggered significant metabolic changes in cucumber leaves and root exudates. The root exudate metabolic changes revealed an active defense mechanism against nano-Cu stress: up-regulation of amino acids to sequester/exclude Cu/nano-Cu; down-regulation of citric acid to reduce the mobilization of Cu ions; ascorbic acid up-regulation to combat reactive oxygen species; and up-regulation of phenolic compounds to improve antioxidant system. Thus, we demonstrate that nontargeted (1)H NMR and GC-MS based metabolomics can successfully identify physiological responses induced by nanoparticles. Root exudates metabolomics revealed important detoxification mechanisms.

  12. α-Glucosidase inhibition and antioxidant activity of an oenological commercial tannin. Extraction, fractionation and analysis by HPLC/ESI-MS/MS and (1)H NMR.

    PubMed

    Muccilli, Vera; Cardullo, Nunzio; Spatafora, Carmela; Cunsolo, Vincenzo; Tringali, Corrado

    2017-01-15

    Two batches of the oenological tannin Tan'Activ R, (toasted oak wood - Quercus robur), were extracted with ethanol. A fractionation on XAD-16 afforded four fractions for each extract. Extracts and fractions were evaluated for antioxidant activity (DPPH), polyphenol content (GAE) and yeast α-glucosidase inhibitory activity. Comparable results were obtained for both columns, fractions X1B and X2B showing the highest antioxidant activity. Fractions X1C and X2C notably inhibited α-glucosidase, with IC50=9.89 and 8.05μg/mL, respectively. Fractions were subjected to HPLC/ESI-MS/MS and (1)H NMR analysis. The main phenolic constituents of both X1B and X2B were a monogalloylglucose isomer (1), a HHDP-glucose isomer (2), castalin (3) gallic acid (4), vescalagin (5), and grandinin (or its isomer roburin E, 6). X1C and X2C showed a complex composition, including non-phenolic constituents. Fractionation of X2C gave a subfraction, with enhanced α-glucosidase inhibitory activity (IC50=6.15μg/mL), with castalagin (7) as the main constituent.

  13. Comprehensive non-targeted analysis of contaminated groundwater of a former ammunition destruction site using 1H-NMR and HPLC-SPE-NMR/TOF-MS.

    PubMed

    Godejohann, Markus; Heintz, Lea; Daolio, Cristina; Berset, Jean-Daniel; Muff, Daniel

    2009-09-15

    The aim of the present study was to explore the capabilities of the combination of 1H NMR (proton nuclear magnetic resonance) mixture analysis and HPLC-SPE-NMR/TOF-MS (high-performance liquid chromatography coupled to solid-phase extraction and nuclear magnetic resonance and time-of-flight mass spectrometry) for the characterization of xenobiotic contaminants in groundwater samples. As an example, solid-phase extracts of two groundwater samples taken from a former ammunition destruction site in Switzerland were investigated. 1H NMR spectra of postcolumn SPE enriched compounds, together with accurate mass measurements, allowed the structural elucidation of unknowns. This untargeted approach allowed us to identify expected residues of explosives such as 2,4,6-trinitrotoluene (2,4,6-TNT), Hexogen (RDX) and Octogen (HMX), degradation products of TNT (1,3,5-trinitrobenzene (1,3,5-TNB), 2-amino-4,6-dinitrotoluene (2-A-4,6-DNT), 3,5-dinitrophenol (3,5-DNP), 3,5-dinitroaniline (3,5-DNA), 2,6-dinitroanthranite, and 2-Hydroxy-4,6-dinitrobenzonitrile), benzoic acid, Bisphenol A (a known endocrine disruptor compound), and some toxicologically relevant additives for propelling charges: Centralite I (1,3-diethyl-1,3-diphenylurea), DPU (N,N-diphenylurethane), N,N-diphenylcarbamate (Acardite II), and N-methyl-N-phenylurethane. To our knowledge, this is the first report of the presence of these additives in environmental samples. Extraction recoveries for Centralite I and DPU have been determined. Contaminants identified by our techniques were quantified based on HPLC-UV (HPLC-ultraviolet detection) and 1H NMR mixture analysis. The concentrations of the contaminants ranged between 0.1 and 48 microg/L assuming 100% recovery for the SPE step.

  14. (13)C NMR Metabolomics: INADEQUATE Network Analysis.

    PubMed

    Clendinen, Chaevien S; Pasquel, Christian; Ajredini, Ramadan; Edison, Arthur S

    2015-06-02

    The many advantages of (13)C NMR are often overshadowed by its intrinsically low sensitivity. Given that carbon makes up the backbone of most biologically relevant molecules, (13)C NMR offers a straightforward measurement of these compounds. Two-dimensional (13)C-(13)C correlation experiments like INADEQUATE (incredible natural abundance double quantum transfer experiment) are ideal for the structural elucidation of natural products and have great but untapped potential for metabolomics analysis. We demonstrate a new and semiautomated approach called INETA (INADEQUATE network analysis) for the untargeted analysis of INADEQUATE data sets using an in silico INADEQUATE database. We demonstrate this approach using isotopically labeled Caenorhabditis elegans mixtures.

  15. New findings on the in vivo antioxidant activity of Curcuma longa extract by an integrated (1)H NMR and HPLC-MS metabolomic approach.

    PubMed

    Dall'Acqua, Stefano; Stocchero, Matteo; Boschiero, Irene; Schiavon, Mariano; Golob, Samuel; Uddin, Jalal; Voinovich, Dario; Mammi, Stefano; Schievano, Elisabetta

    2016-03-01

    Curcuminoids possess powerful antioxidant activity as demonstrated in many chemical in vitro tests and in several in vivo trials. Nevertheless, the mechanism of this activity is not completely elucidated and studies on the in vivo antioxidant effects are still needed. Metabolomics may be used as an attractive approach for such studies and in this paper, we describe the effects of oral administration of a Curcuma longa L. extract (150 mg/kg of total curcuminoids) to 12 healthy rats with particular attention to urinary markers of oxidative stress. The experiment was carried out over 33 days and changes in the 24-h urine samples metabolome were evaluated by (1)H NMR and HPLC-MS. Both techniques produced similar representations for the collected samples confirming our previous study. Modifications of the urinary metabolome lead to the observation of different variables proving the complementarity of (1)H NMR and HPLC-MS for metabolomic purposes. The urinary levels of allantoin, m-tyrosine, 8-hydroxy-2'-deoxyguanosine, and nitrotyrosine were decreased in the treated group thus supporting an in vivo antioxidant effect of the oral administration of Curcuma extract to healthy rats. On the other hand, urinary TMAO levels were higher in the treated compared to the control group suggesting a role of curcumin supplementation on microbiota or on TMAO urinary excretion. Furthermore, the urinary levels of the sulphur containing compounds taurine and cystine were also changed suggesting a role for such constituents in the biochemical pathways involved in Curcuma extract bioactivity and indicating the need for further investigation on the complex role of antioxidant curcumin effects.

  16. Identification of endogenous metabolites in human sperm cells using proton nuclear magnetic resonance ((1) H-NMR) spectroscopy and gas chromatography-mass spectrometry (GC-MS).

    PubMed

    Paiva, C; Amaral, A; Rodriguez, M; Canyellas, N; Correig, X; Ballescà, J L; Ramalho-Santos, J; Oliva, R

    2015-05-01

    The objective of this study was to contribute to the first comprehensive metabolomic characterization of the human sperm cell through the application of two untargeted platforms based on proton nuclear magnetic resonance ((1) H-NMR) spectroscopy and gas chromatography coupled to mass spectrometry (GC-MS). Using these two complementary strategies, we were able to identify a total of 69 metabolites, of which 42 were identified using NMR, 27 using GC-MS and 4 by both techniques. The identity of some of these metabolites was further confirmed by two-dimensional (1) H-(1) H homonuclear correlation spectroscopy (COSY) and (1) H-(13) C heteronuclear single-quantum correlation (HSQC) spectroscopy. Most of the metabolites identified are reported here for the first time in mature human spermatozoa. The relationship between the metabolites identified and the previously reported sperm proteome was also explored. Interestingly, overrepresented pathways included not only the metabolism of carbohydrates, but also of lipids and lipoproteins. Of note, a large number of the metabolites identified belonged to the amino acids, peptides and analogues super class. The identification of this initial set of metabolites represents an important first step to further study their function in male gamete physiology and to explore potential reasons for dysfunction in future studies. We also demonstrate that the application of NMR and MS provides complementary results, thus constituting a promising strategy towards the completion of the human sperm cell metabolome.

  17. Discovery of safety biomarkers for realgar in rat urine using UFLC-IT-TOF/MS and 1H NMR based metabolomics.

    PubMed

    Huang, Yin; Tian, Yuan; Li, Geng; Li, Yuanyuan; Yin, Xinjuan; Peng, Can; Xu, Fengguo; Zhang, Zunjian

    2013-05-01

    As an arsenical, realgar (As4S4) is known as a poison and paradoxically as a therapeutic agent. However, a complete understanding of the precise biochemical alterations accompanying the toxicity and therapy effects of realgar is lacking. Using a combined ultrafast liquid chromatography (UFLC) coupled with ion trap time-of-flight mass spectrometry (IT-TOF/MS) and (1)H NMR spectroscopy based metabolomics approach, we were able to delineate significantly altered metabolites in the urine samples of realgar-treated rats. The platform stability of the liquid chromatography LC/MS and NMR techniques was systematically investigated, and the data processing method was carefully optimized. Our results indicate significant perturbations in amino acid metabolism, citric acid cycle, choline metabolism, and porphyrin metabolism. Thirty-six metabolites were proposed as potential safety biomarkers related to disturbances caused by realgar, and glycine and serine are expected to serve as the central contacts in the metabolic pathways related to realgar-induced disturbance. The LC/MS and NMR based metabolomics approach established provided a systematic and holistic view of the biochemical effects of realgar on rats, and might be employed to investigate other drugs or xenobiotics in the future.

  18. 13C NMR of tunnelling methyl groups

    NASA Astrophysics Data System (ADS)

    Detken, A.

    The dipolar interactions between the protons and the central 13C nucleus of a 13CH3 group are used to study rotational tunnelling and incoherent dynamics of such groups in molecular solids. Single-crystal 13C NMR spectra are derived for arbitrary values of the tunnel frequency upsilon t. Similarities to ESR and 2H NMR are pointed out. The method is applied to three different materials. In the hydroquinone/acetonitrile clathrate, the unique features in the 13C NMR spectra which arise from tunnelling with a tunnel frequency that is much larger than the dipolar coupling between the methyl protons and the 13C nucleus are demonstrated, and the effects of incoherent dynamics are studied. The broadening of the 13C resonances is related to the width of the quasi-elastic line in neutron scattering. Selective magnetization transfer experiments for studying slow incoherent dynamics are proposed. For the strongly hindered methyl groups of L-alanine, an upper limit for upsilon is derived from the 13C NMR spectrum. In aspirinTM (acetylsalicylic acid), incoherent reorientations dominate the spectra down to the lowest temperatures studied; their rate apparently increases with decreasing temperature below 25K.

  19. Dereplication of antioxidant compounds in Bene (Pistacia atlantica subsp. mutica) hull using a multiplex approach of HPLC-DAD, LC-MS and (1)H NMR techniques.

    PubMed

    Rezaie, Mitra; Farhoosh, Reza; Pham, Ngoc; Quinn, Ronald J; Iranshahi, Mehrdad

    2016-01-05

    Bene is an edible fruit from the tree Pistacia atlantica subsp. mutica, and is of steadily growing interest in recent years due to its significant antioxidant properties and potential health benefits. An antioxidant activity-guided fractionation of the methanol extract from Bene hull together with an integrated approach of HPLC-DAD, LC-MS and (1)H NMR techniques led to the identification of main antioxidant phenolic compounds for the first time. Radical scavenging activity of each fraction/compound was tested using DPPH and FRAP assays. The phenolic content of the fractions was also determined by Folin-Ciocalteu's method. The main identified antioxidant compounds were luteolin (46.53% w/w of total extract), gallic acid (9.84% w/w), 2″-O-galloylisoquercitrin (0.53% w/w), quercetin 3-rutinoside (0.34% w/w) and 2″-O-cis-caffeoylquercitrin (0.26% w/w). The minor antioxidant compounds were also identified by liquid chromatography-positive/negative electrospray ionization tandem mass spectrometry. The structure-antioxidant activity relationship of identified phenolics are also discussed in this paper.

  20. 13C-NMR spectra and contact time experiment for Skjervatjern fulvic and humic acids

    USGS Publications Warehouse

    Malcolm, R.L.

    1992-01-01

    The T(CP) and T(1p) time constants for Skjervatjern fulvic and humic acids were determined to be short with T(CP) values ranging from 0.14 ms to 0.53 ms and T(1p) values ranging from 3.3 ms to 5.9 ms. T(CP) or T(1p) time constants at a contact time of 1 ms are favorable for quantification of 13C-NMR spectra. Because of the short T(CP) values, correction factors for signal intensity for various regions of the 13C-NMR spectra would be necessary at contact times greater than 1.1 ms or less than 0.9 ms. T(CP) and T(1p) values have a limited non-homogeneity within Skjervatjern fulvic and humic acids. A pulse delay or repeat time of 700 ms is more than adequate for quantification of these 13C-NMR spectra. Paramagnetic effects in these humic substances are precluded due to low inorganic ash contents, low contents of Fe, Mn, and Co, and low organic free-radical contents. The observed T(CP) values suggest that all the carbon types in Skjervatjern fulvic and humic acids are fully cross-polarized before significant proton relaxation occurs. The 13C-NMR spectra for Skjervatjern fulvic acid is similar to most aquatic fulvic acids as it is predominantly aliphatic, low in aromaticity (fa1 = 24), low in phenolic content, high in carboxyl content, and has no resolution of a methoxyl peak. The 13C-NMR spectra for Skjervatjern humic acid is also similar to most other aquatic humic acids in that it is also predominantly aliphatic, high in aromaticity (fa1 = 38), moderate in phenolic content, moderate in carboxyl content, and has a clear resolution of a methoxyl carbon region. After the consideration of the necessary 13C-NMR experimental conditions, these spectra are considered to be quantitative. With careful consideration of the previously determined 13C-NMR experimental conditions, quantitative spectra can be obtained for humic substances in the future from the HUMEX site. Possible changes in humic substances due to acidification should be determined from 13C-NMR data.

  1. Forced degradation of fingolimod: effect of co-solvent and characterization of degradation products by UHPLC-Q-TOF-MS/MS and 1H NMR.

    PubMed

    Patel, Prinesh N; Kalariya, Pradipbhai D; Gananadhamu, S; Srinivas, R

    2015-11-10

    Fingolimod (FGL), an immunomodulator drug for treating multiple sclerosis, was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress, as per International Conference on Harmonization specified conditions. The drug showed extensive degradation under base hydrolysis, however, it was stable under all other conditions. A total of three degradation products (DPs) were observed. The chromatographic separation of the drug and its degradation products was achieved on a Fortis C18 (100×2.1mm, 1.7μm) column with a mobile phase composed of 0.1% formic acid (Solvent A) and acetonitrile (Solvent B) in gradient mode. All the DPs were identified and characterized by liquid chromatography-quadrupole time of flight-mass spectrometry (LC-Q-TOF-MS) in combination with accurate mass measurements. The major DP was isolated and characterized by Nuclear Magnetic resonance spectroscopy. This is a typical case of degradation where acetonitrile used as co-solvent in stress studies, reacts with FGL in base hydrolytic conditions to produce acetylated DPs. Hence, it can be suggested that acetonitrile is not preferable as a co-solvent for stress degradation of FGL. The developed UHPLC method was validated as per ICH guidelines.

  2. Diffusion and conformation of peptide-functionalized polyphenylene dendrimers studied by fluorescence correlation and 13C NMR spectroscopy.

    PubMed

    Koynov, K; Mihov, G; Mondeshki, M; Moon, C; Spiess, H W; Müllen, K; Butt, H-J; Floudas, G

    2007-05-01

    We report on the combined use of fluorescence correlation spectroscopy (FCS) and 1H and 13C NMR spectroscopy to detect the size and type of peptide secondary structures in a series of poly-Z-L-lysine functionalized polyphenylene dendrimers bearing the fluorescent perylenediimide core in solution. In dilute solution, the size of the molecule as detected from FCS and 1H NMR diffusion measurements matches nicely. We show that FCS is a sensitive probe of the core size as well as of the change in the peptide secondary structure. However, FCS is less sensitive to functionality. A change in the peptide secondary conformation from beta-sheets to alpha-helices detected by 13C NMR spectroscopy gives rise to a steep increase in the hydrodynamic radii for number of residues n > or = 16. Nevertheless, helices are objects of low persistence.

  3. 1H-NMR and MS Based Metabolomics Study of the Intervention Effect of Curcumin on Hyperlipidemia Mice Induced by High-Fat Diet

    PubMed Central

    Li, Ze-Yun; Ding, Li-Li; Li, Jin-Mei; Xu, Bao-Li; Yang, Li; Bi, Kai-Shun; Wang, Zheng-Tao

    2015-01-01

    Curcumin, a principle bioactive component of Curcuma longa L, is well known for its anti-hyperlipidemia effect. However, no holistic metabolic information of curcumin on hyperlipidemia models has been revealed, which may provide us an insight into the underlying mechanism. In the present work, NMR and MS based metabolomics was conducted to investigate the intervention effect of curcumin on hyperlipidemia mice induced by high-fat diet (HFD) feeding for 12 weeks. The HFD induced animals were orally administered with curcumin (40, 80 mg/kg) or lovastatin (30 mg/kg, positive control) once a day during the inducing period. Serum biochemistry assay of TC, TG, LDL-c, and HDL-c was conducted and proved that treatment of curcumin or lovastatin can significantly improve the lipid profiles. Subsequently, metabolomics analysis was carried out for urine samples. Orthogonal Partial Least Squares-Discriminant analysis (OPLS-DA) was employed to investigate the anti-hyperlipidemia effect of curcumin and to detect related potential biomarkers. Totally, 35 biomarkers were identified, including 31 by NMR and nine by MS (five by both). It turned out that curcumin treatment can partially recover the metabolism disorders induced by HFD, with the following metabolic pathways involved: TCA cycle, glycolysis and gluconeogenesis, synthesis of ketone bodies and cholesterol, ketogenesis of branched chain amino acid, choline metabolism, and fatty acid metabolism. Besides, NMR and MS based metabolomics proved to be powerful tools in investigating pharmacodynamics effect of natural products and underlying mechanisms. PMID:25786031

  4. Quantitative 13C NMR characterization of fast pyrolysis oils

    DOE PAGES

    Happs, Renee M.; Lisa, Kristina; Ferrell, III, Jack R.

    2016-10-20

    Quantitative 13C NMR analysis of model catalytic fast pyrolysis (CFP) oils following literature procedures showed poor agreement for aromatic hydrocarbons between NMR measured concentrations and actual composition. Furthermore, modifying integration regions based on DEPT analysis for aromatic carbons resulted in better agreement. Solvent effects were also investigated for hydrotreated CFP oil.

  5. Functional groups identified by solid state 13C NMR spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Animal manure is generally high in organic matter intensity so it is well suitable for 13C nuclear magnetic resonance (NMR) analysis. Solid-state 13C NMR techniques used in characterizing organic matter and its components include, but are not limited to, cross-polarization /magic angle spinning (CP...

  6. 1H and 13C NMR assignments for two new angular furanocoumarin glycosides from Peucedanum praeruptorum.

    PubMed

    Chang, Haitao; Okada, Yoshihito; Okuyama, Toru; Tu, Pengfei

    2007-07-01

    Two novel angular-type furanocoumarin glycosides, peucedanoside A (1) and peucedanoside B (2), along with a known compound apterin (3), were isolated from the roots of Peucedanum praeruptorum Dunn. Their chemical structures were determined by MS, NMR spectroscopy and chemical analysis. Complete assignments of the 1H and 13C NMR spectroscopic data were achieved by 1D and 2D NMR experiments including DEPT, HSQC, HMBC and ROESY.

  7. Novel approaches for the taxonomic and metabolic characterization of lactobacilli: Integration of 16S rRNA gene sequencing with MALDI-TOF MS and 1H-NMR

    PubMed Central

    Parolin, Carola; Giordani, Barbara; Compri, Monica; Cevenini, Roberto; Vitali, Beatrice

    2017-01-01

    Lactobacilli represent a wide range of bacterial species with several implications for the human host. They play a crucial role in maintaining the ecological equilibrium of different biological niches and are essential for fermented food production and probiotic formulation. Despite the consensus about the ‘health-promoting’ significance of Lactobacillus genus, its genotypic and phenotypic characterization still poses several difficulties. The aim of this study was to assess the integration of different approaches, genotypic (16S rRNA gene sequencing), proteomic (MALDI-TOF MS) and metabolomic (1H-NMR), for the taxonomic and metabolic characterization of Lactobacillus species. For this purpose we analyzed 40 strains of various origin (intestinal, vaginal, food, probiotics), belonging to different species. The high discriminatory power of MALDI-TOF for species identification was underlined by the excellent agreement with the genotypic analysis. Indeed, MALDI-TOF allowed to correctly identify 39 out of 40 Lactobacillus strains at the species level, with an overall concordance of 97.5%. In the perspective to simplify the MALDI TOF sample preparation, especially for routine practice, we demonstrated the perfect agreement of the colony-picking from agar plates with the protein extraction protocol. 1H-NMR analysis, applied to both culture supernatants and bacterial lysates, identified a panel of metabolites whose variations in concentration were associated with the taxonomy, but also revealed a high intra-species variability that did not allow a species-level identification. Therefore, despite not suitable for mere taxonomic purposes, metabolomics can be useful to correlate particular biological activities with taxonomy and to understand the mechanisms related to the antimicrobial effect shown by some Lactobacillus species. PMID:28207855

  8. Compositional differences among Chinese soy sauce types studied by (13)C NMR spectroscopy coupled with multivariate statistical analysis.

    PubMed

    Kamal, Ghulam Mustafa; Wang, Xiaohua; Bin Yuan; Wang, Jie; Sun, Peng; Zhang, Xu; Liu, Maili

    2016-09-01

    Soy sauce a well known seasoning all over the world, especially in Asia, is available in global market in a wide range of types based on its purpose and the processing methods. Its composition varies with respect to the fermentation processes and addition of additives, preservatives and flavor enhancers. A comprehensive (1)H NMR based study regarding the metabonomic variations of soy sauce to differentiate among different types of soy sauce available on the global market has been limited due to the complexity of the mixture. In present study, (13)C NMR spectroscopy coupled with multivariate statistical data analysis like principle component analysis (PCA), and orthogonal partial least square-discriminant analysis (OPLS-DA) was applied to investigate metabonomic variations among different types of soy sauce, namely super light, super dark, red cooking and mushroom soy sauce. The main additives in soy sauce like glutamate, sucrose and glucose were easily distinguished and quantified using (13)C NMR spectroscopy which were otherwise difficult to be assigned and quantified due to serious signal overlaps in (1)H NMR spectra. The significantly higher concentration of sucrose in dark, red cooking and mushroom flavored soy sauce can directly be linked to the addition of caramel in soy sauce. Similarly, significantly higher level of glutamate in super light as compared to super dark and mushroom flavored soy sauce may come from the addition of monosodium glutamate. The study highlights the potentiality of (13)C NMR based metabonomics coupled with multivariate statistical data analysis in differentiating between the types of soy sauce on the basis of level of additives, raw materials and fermentation procedures.

  9. Discrimination of wild types and hybrids of Duboisia myoporoides and Duboisia leichhardtii at different growth stages using (1)H NMR-based metabolite profiling and tropane alkaloids-targeted HPLC-MS analysis.

    PubMed

    Ullrich, Sophie Friederike; Averesch, Nils J H; Castellanos, Leonardo; Choi, Young Hae; Rothauer, Andreas; Kayser, Oliver

    2016-11-01

    Duboisia species, which belong to the family of Solanaceae, are commercially cultivated in large scale, as they are main source of the pharmaceutically-used active compound scopolamine. In this study, (1)H NMR-based metabolite profiling linking primary with secondary metabolism and additional quantification via HPCL-MS with special focus on the tropane alkaloids were applied to compare leaf and root extracts of three wild types and two hybrids of Duboisia myoporoides and D. leichhardtii at different developmental stages grown under controlled conditions in climate chambers and under agricultural field plantation. Based on the leaf extracts, a clear distinction between the Duboisia hybrids and the wild types Duboisia myoporoides and D. leichhardtii using principal component analysis of (1)H NMR data was observed. The average content in scopolamine in the hybrids of Duboisia cultivated in climate chambers increased significantly from month 3-6 after potting of the rooted cuttings, however not so for the examined wild types. The Duboisia hybrids grown in climate chambers showed higher growth and contained more sugars and amino acids than Duboisia hybrids grown in the field, which in contrast showed an enhanced flux towards tropane alkaloids as well as flavonoids. For a more detailed analysis of tropane alkaloids, an appropriate HPLC-MS method was developed and validated. The measurements revealed large differences in the alkaloid pattern within the different genotypes under investigation, especially regarding the last enzymatic step, the conversion from hyoscamine to scopolamine by the hyoscyamine 6β-hydroxylase. Scopolamine was found in highest concentrations in Duboisia hybrids (20.04 ± 4.05 and 17.82 ± 3.52 mg/g dry wt) followed by Duboisia myoporoides (12.71 ± 2.55 mg/g dry wt), both showing a high selectivity for scopolamine in contrast to Duboisia leichhardtii (3.38 ± 0.59 and 5.09 ± 1.24 mg/g dry wt) with hyoscyamine being the

  10. 13C NMR Metabolomics: Applications at Natural Abundance

    PubMed Central

    2015-01-01

    13C NMR has many advantages for a metabolomics study, including a large spectral dispersion, narrow singlets at natural abundance, and a direct measure of the backbone structures of metabolites. However, it has not had widespread use because of its relatively low sensitivity compounded by low natural abundance. Here we demonstrate the utility of high-quality 13C NMR spectra obtained using a custom 13C-optimized probe on metabolomic mixtures. A workflow was developed to use statistical correlations between replicate 1D 13C and 1H spectra, leading to composite spin systems that can be used to search publicly available databases for compound identification. This was developed using synthetic mixtures and then applied to two biological samples, Drosophila melanogaster extracts and mouse serum. Using the synthetic mixtures we were able to obtain useful 13C–13C statistical correlations from metabolites with as little as 60 nmol of material. The lower limit of 13C NMR detection under our experimental conditions is approximately 40 nmol, slightly lower than the requirement for statistical analysis. The 13C and 1H data together led to 15 matches in the database compared to just 7 using 1H alone, and the 13C correlated peak lists had far fewer false positives than the 1H generated lists. In addition, the 13C 1D data provided improved metabolite identification and separation of biologically distinct groups using multivariate statistical analysis in the D. melanogaster extracts and mouse serum. PMID:25140385

  11. Characterization of heroin samples by 1H NMR and 2D DOSY 1H NMR.

    PubMed

    Balayssac, Stéphane; Retailleau, Emmanuel; Bertrand, Geneviève; Escot, Marie-Pierre; Martino, Robert; Malet-Martino, Myriam; Gilard, Véronique

    2014-01-01

    Twenty-four samples of heroin from different illicit drug seizures were analyzed using proton Nuclear Magnetic Resonance ((1)H NMR) and two-dimensional diffusion-ordered spectroscopy (2D DOSY) (1)H NMR. A careful assignment and quantification of (1)H signals enabled a comprehensive characterization of the substances present in the samples investigated: heroin, its main related impurities (6-acetylmorphine, acetylcodeine, morphine, noscapine and papaverine) and cutting agents (caffeine and acetaminophen in nearly all samples as well as lactose, lidocaine, mannitol, piracetam in one sample only), and hence to establish their spectral signatures. The good agreement between the amounts of heroin, noscapine, caffeine and acetaminophen determined by (1)H NMR and gas chromatography, the reference method in forensic laboratories, demonstrates the validity of the (1)H NMR technique. In this paper, 2D DOSY (1)H NMR offers a new approach for a whole characterization of the various components of these complex mixtures.

  12. Identification and quantitative determination of lignans in Cedrus atlantica resins using 13C NMR spectroscopy.

    PubMed

    Nam, Anne-Marie; Paoli, Mathieu; Castola, Vincent; Casanova, Joseph; Bighelli, Ange

    2011-03-01

    Identification and quantitative determination of individual components of resin collected on the trunk of 28 Cedrus atlantica trees, grown in Corsica, has been carried out using 13C NMR spectroscopy. Eight resin acids bearing either the pimarane or abietane skeleton, two monoterpene hydrocarbons and four oxygenated neutral diterpenes have been identified, as well as three lignans, scarcely found in resins. Three groups could be distinguished within the 28 resin samples. The nine samples of Group I had their composition dominated by diterpene acids (33.7-45.8%), with abietic acid (6.2-18.7%) and isopimaric acid (5.1-12.6%) being the major components. The four samples of Group II contained resin acids (main components) and lignans in moderate amounts (up to 10.3%). Conversely, lignans (38.8-63.8%) were by far the major components of the 15 samples of Group III. Depending on the sample, the major component was pinoresinol (18.1-38.9%), lariciresinol (17.2-33.7%) or lariciresinol 9'-acetate (16.9-29.1%). Finally, due to the high biological interest in lignans, a rapid procedure, based on 1H NMR spectroscopy, was developed for quantification of lignans in resins of C. atlantica.

  13. Electronic states and molecular dynamics of single-component molecular conductors [M (tmdt) 2] (M =Ni , Pt) studied by 13C and 1H NMR

    NASA Astrophysics Data System (ADS)

    Takagi, Rina; Miyagawa, Kazuya; Yoshimura, Masahide; Gangi, Hiro; Kanoda, Kazushi; Zhou, Biao; Idobata, Yuki; Kobayashi, Akiko

    2016-01-01

    The molecular conductors [M(tmdt) 2] (M =Ni , Pt) consisting of single molecular species are investigated with 13C NMR and 1H NMR. The temperature dependences of the 13C NMR shift and relaxation rate provide microscopic evidence for the metallic nature with appreciable electron correlations. Both compounds exhibit an anomalous frequency-dependent enhancement in the 1H nuclear spin-lattice relaxation rate in a wide temperature range. These observations signify the presence of extraordinary molecular motions with low energy excitations.

  14. 13C NMR of Nephila clavipes major ampullate silk gland.

    PubMed

    Hijirida, D H; Do, K G; Michal, C; Wong, S; Zax, D; Jelinski, L W

    1996-12-01

    The major ampullate glands of the spider Nephila clavipes contain approximately 0.2 microliter each of a highly concentrated (approximately 50%) solution of silk fibroin. Therefore, the reservoir of silk in these glands presents an ideal opportunity to observe prefolded conformations of a protein in its native state. To this end, the structure and conformation of major ampullate gland silk fibroin within the glands of the spider N. clavipes were examined by 13C NMR spectroscopy. These results were compared to those from silk protein first drawn from the spinneret and then denatured. The 13C NMR chemical shifts, along with infrared and circular dichroism data, suggest that the silk fibroin in the glands exists in dynamically averaged helical conformations. Furthermore, there is no evidence of proline residues in U-(13)C-D-glucose-labeled silk. This transient prefolded "molten fibril" state may correspond to the silk I form found in Bombyx mori silk. There is no evidence of the final beta-sheet structure in the ampullate gland silk fibroin before final silk processing. However, the conformation of silk in the glands appears to be in a highly metastable state, as plasticization with water produces the beta-sheet structure. Therefore, the ducts connecting the ampullate glands to the spinnerets play a larger role in silk processing than previously thought.

  15. Chemical composition of Ivorian Artabotrys insignis leaf oil. Combined analysis including (13)C NMR, to quantify germacrene A and β-elemene.

    PubMed

    Gooré, Stéphane G; Ouattara, Zana A; Yapi, Thierry A; Békro, Yves-Alain; Tomi, Pierre; Paoli, Mathieu; Tomi, Félix

    2017-02-20

    The chemical composition of leaf essential oil from Artabotrys insignis Engler & Diels collected from Cote d'Ivoire was determined by GC(FID), GC-MS and (13)C NMR. The main compounds were β-elemene (66.8%) and germacrene A (17.1%). The true content of germacrene A/β-elemene was obtained by combining GC(FID) and (13)C NMR data.

  16. Complete (1) H NMR assignment of cedranolides.

    PubMed

    Perez-Hernandez, Nury; Gordillo-Roman, Barbara; Arrieta-Baez, Daniel; Cerda-Garcia-Rojas, Carlos M; Joseph-Nathan, Pedro

    2017-03-01

    Complete and unambiguous (1) H NMR chemical shift assignment of α-cedrene (2) and cedrol (9), as well as for α-pipitzol (1), isocedrol (10), and the six related compounds 3-8 has been established by iterative full spin analysis using the PERCH NMR software (PERCH Solutions Ltd., Kuopio, Finland). The total sets of coupling constants are described and correlated with the conformational equilibria of the five-membered ring of 1-10, which were calculated using the complete basis set method. Copyright © 2015 John Wiley & Sons, Ltd.

  17. Quantitative analysis of deuterium using the isotopic effect on quaternary (13)C NMR chemical shifts.

    PubMed

    Darwish, Tamim A; Yepuri, Nageshwar Rao; Holden, Peter J; James, Michael

    2016-07-13

    Quantitative analysis of specifically deuterated compounds can be achieved by a number of conventional methods, such as mass spectroscopy, or by quantifying the residual (1)H NMR signals compared to signals from internal standards. However, site specific quantification using these methods becomes challenging when dealing with non-specifically or randomly deuterated compounds that are produced by metal catalyzed hydrothermal reactions in D2O, one of the most convenient deuteration methods. In this study, deuterium-induced NMR isotope shifts of quaternary (13)C resonances neighboring deuterated sites have been utilized to quantify the degree of isotope labeling of molecular sites in non-specifically deuterated molecules. By probing (13)C NMR signals while decoupling both proton and deuterium nuclei, it is possible to resolve (13)C resonances of the different isotopologues based on the isotopic shifts and the degree of deuteration of the carbon atoms. We demonstrate that in different isotopologues, the same quaternary carbon, neighboring partially deuterated carbon atoms, are affected to an equal extent by relaxation. Decoupling both nuclei ((1)H, (2)H) resolves closely separated quaternary (13)C signals of the different isotopologues, and allows their accurate integration and quantification under short relaxation delays (D1 = 1 s) and hence fast accumulative spectral acquisition. We have performed a number of approaches to quantify the deuterium content at different specific sites to demonstrate a convenient and generic analysis method for use in randomly deuterated molecules, or in cases of specifically deuterated molecules where back-exchange processes may take place during work up.

  18. Characterization of uniformly and atom-specifically 13C-labeled heparin and heparan sulfate polysaccharide precursors using 13C NMR spectroscopy and ESI mass spectrometry

    PubMed Central

    Nguyen, Thao K. N.; Tran, Vy M.; Victor, Xylophone V.; Skalicky, Jack J.; Kuberan, Balagurunathan

    2010-01-01

    The biological actions of heparin and heparan sulfate, two structurally related glycosaminoglycans, depend on the organization of the complex heparanome. Due to the structural complexity of the heparanome, the sequence of variably sulfonated uronic acid and glucosamine residues is usually characterized by the analysis of smaller oligosaccharide and disaccharide fragments. Even characterization of smaller heparin/heparan sulfate oligosaccharide or disaccharide fragments using simple 1D 1H NMR spectroscopy is often complicated by the extensive signal overlap. 13C NMR signals, on the other hand, overlap less and therefore, 13C NMR spectroscopy can greatly facilitate the structural elucidation of the complex heparanome and provide finer insights into the structural basis for biological functions. This is the first report of the preparation of anomeric carbon-specific 13C-labeled heparin/heparan sulfate precursors from the Escherichia coli K5 strain. Uniformly 13C- and 15N-labeled precursors were also produced and characterized by 13C NMR spectroscopy. Mass spectrometric analysis of enzymatically fragmented disaccharides revealed that anomeric carbon-specific labeling efforts resulted in a minor loss/scrambling of 13C in the precursor backbone, whereas uniform labeling efforts resulted in greater than 95% 13C isotope enrichment in the precursor backbone. These labeled precursors provided high-resolution NMR signals with great sensitivity and set the stage for studying the heparanome–proteome interactions. PMID:20832774

  19. A novel approach to the rapid assignment of (13)C NMR spectra of major components of vegetable oils such as avocado, mango kernel and macadamia nut oils.

    PubMed

    Retief, Liezel; McKenzie, Jean M; Koch, Klaus R

    2009-09-01

    Assignment of (13)C nuclear magnetic resonance (NMR) spectra of major fatty acid components of South African produced vegetable oils was attempted using a method in which the vegetable oil was spiked with a standard triacylglycerol. This proved to be inadequate and therefore a new rapid and potentially generic graphical linear correlation method is proposed for assignment of the (13)C NMR spectra of major fatty acid components of apricot kernel, avocado pear, grapeseed, macadamia nut, mango kernel and marula vegetable oils. In this graphical correlation method, chemical shifts of fatty acids present in a known standard triacylglycerol is plotted against the corresponding chemical shifts of fatty acids present in the vegetable oils. This new approach (under carefully defined conditions and concentrations) was found especially useful for spectrally crowded regions where significant peak overlap occurs and was validated with the well-known (13)C NMR spectrum of olive oil which has been extensively reported in the literature. In this way, a full assignment of the (13)C{1H} NMR spectra of the vegetable oils, as well as tripalmitolein was readily achieved and the resonances belonging to the palmitoleic acid component of the triacylglycerols in the case of macadamia nut and avocado pear oil resonances were also assigned for the first time in the (13)C NMR spectra of these oils.

  20. {sup 1}H NMR spectroscopic studies establish that heparanase is a retaining glycosidase

    SciTech Connect

    Wilson, Jennifer C.; Laloo, Andrew Elohim; Singh, Sanjesh; Ferro, Vito

    2014-01-03

    Highlights: •{sup 1}H and {sup 13}C NMR chemical shifts of fondaparinux were fully assigned by 1D and 2D NMR techniques. •Hydrolysis of fondaparinux by heparanase was monitored by {sup 1}H NMR spectroscopy. •Heparanase is established to be a retaining glycosidase. -- Abstract: Heparanase is an endo-β-glucuronidase that cleaves heparan sulfate side chains of proteoglycans in basement membranes and the extracellular matrix (ECM). Heparanase is implicated in several diverse pathological processes associated with ECM degradation such as metastasis, inflammation and angiogenesis and is thus an important target for anti-cancer and anti-inflammatory drug discovery. Heparanase has been classed as belonging to the clan A glycoside hydrolase family 79 based on sequence analysis, secondary structure predictions and mutagenic analysis, and thus it has been inferred that it is a retaining glycosidase. However, there has been no direct experimental evidence to support this conclusion. Herein we describe {sup 1}H NMR spectroscopic studies of the hydrolysis of the pentasaccharide substrate fondaparinux by heparanase, and provide conclusive evidence that heparanase hydrolyses its substrate with retention of configuration and is thus established as a retaining glycosidase. Knowledge of the mechanism of hydrolysis may have implications for future design of inhibitors for this important drug target.

  1. DFT calculations of 1H and 13C NMR chemical shifts in transition metal hydrides.

    PubMed

    del Rosal, I; Maron, L; Poteau, R; Jolibois, F

    2008-08-14

    Transition metal hydrides are of great interest in chemistry because of their reactivity and their potential use as catalysts for hydrogenation. Among other available techniques, structural properties in transition metal (TM) complexes are often probed by NMR spectroscopy. In this paper we will show that it is possible to establish a viable methodological strategy in the context of density functional theory, that allows the determination of 1H NMR chemical shifts of hydride ligands attached to transition metal atoms in mononuclear systems and clusters with good accuracy with respect to experiment. 13C chemical shifts have also been considered in some cases. We have studied mononuclear ruthenium complexes such as Ru(L)(H)(dppm)2 with L = H or Cl, cationic complex [Ru(H)(H2O)(dppm)2]+ and Ru(H)2(dppm)(PPh3)2, in which hydride ligands are characterized by a negative 1H NMR chemical shift. For these complexes all calculations are in relatively good agreement compared to experimental data with errors not exceeding 20% except for the hydrogen atom in Ru(H)2(dppm)(PPh3)2. For this last complex, the relative error increases to 30%, probably owing to the necessity to take into account dynamical effects of phenyl groups. Carbonyl ligands are often encountered in coordination chemistry. Specific issues arise when calculating 1H or 13C NMR chemical shifts in TM carbonyl complexes. Indeed, while errors of 10 to 20% with respect to experiment are often considered good in the framework of density functional theory, this difference in the case of mononuclear carbonyl complexes culminates to 80%: results obtained with all-electron calculations are overall in very satisfactory agreement with experiment, the error in this case does not exceed 11% contrary to effective core potentials (ECPs) calculations which yield errors always larger than 20%. We conclude that for carbonyl groups the use of ECPs is not recommended, although their use could save time for very large systems, for

  2. Identification of fucans from four species of sea cucumber by high temperature 1H NMR

    NASA Astrophysics Data System (ADS)

    Wu, Nian; Chen, Shiguo; Ye, Xingqian; Li, Guoyun; Yin, Li'ang; Xue, Changhu

    2014-10-01

    Acidic polysaccharide, which has various biological activities, is one of the most important components of sea cucumber. In the present study, crude polysaccharide was extracted from four species of sea cucumber from three different geographical zones, Pearsonothuria graeffei ( Pg) from Indo-Pacific, Holothuria vagabunda ( Hv) from Norwegian Coast, Stichopus tremulu ( St) from Western Indian Ocean, and Isostichopus badionotu ( Ib) from Western Atlantic. The polysaccharide extract was separated and purified with a cellulose DEAE anion-exchange column to obtain corresponding sea cucumber fucans (SC-Fucs). The chemical property of these SC-Fucs, including molecular weight, monosaccharide composition and sulfate content, was determined. Their structure was compared simply with fourier infrared spectrum analyzer and identified with high temperature 1H nuclear magnetic resonance spectrum analyzer (NMR) and room temperature 13C NMR. The results indicated that Fuc- Pg obtained from the torrid zone mainly contained 2,4-O-disulfated and non-sulfated fucose residue, whereas Fuc- Ib from the temperate zone contained non-, 2-O- and 2,4-O-disulfated fucose residue; Fuc- St from the frigid zone and Fuc- Hv from the torrid zone contained mainly non-sulfated fucose residue. The proton of SC-Fucs was better resolved via high temperature 1H NMR than via room temperature 1H NMR. The fingerprint of sea cucumber in different sea regions was established based on the index of anomer hydrogen signal in SC-Fucs. Further work will help to understand whether there exists a close relationship between the geographical area of sea cucumber and the sulfation pattern of SC-Fucs.

  3. Teaching 1H NMR Spectrometry Using Computer Modeling.

    ERIC Educational Resources Information Center

    Habata, Yoichi; Akabori, Sadatoshi

    2001-01-01

    Molecular modeling by computer is used to display stereochemistry, molecular orbitals, structure of transition states, and progress of reactions. Describes new ideas for teaching 1H NMR spectroscopy using computer modeling. (Contains 12 references.) (ASK)

  4. Positional Enrichment by Proton Analysis (PEPA): A One-Dimensional (1) H-NMR Approach for (13) C Stable Isotope Tracer Studies in Metabolomics.

    PubMed

    Vinaixa, Maria; Rodríguez, Miguel A; Aivio, Suvi; Capellades, Jordi; Gómez, Josep; Canyellas, Nicolau; Stracker, Travis H; Yanes, Oscar

    2017-03-20

    A novel metabolomics approach for NMR-based stable isotope tracer studies called PEPA is presented, and its performance validated using human cancer cells. PEPA detects the position of carbon label in isotopically enriched metabolites and quantifies fractional enrichment by indirect determination of (13) C-satellite peaks using 1D-(1) H-NMR spectra. In comparison with (13) C-NMR, TOCSY and HSQC, PEPA improves sensitivity, accelerates the elucidation of (13) C positions in labeled metabolites and the quantification of the percentage of stable isotope enrichment. Altogether, PEPA provides a novel framework for extending the high-throughput of (1) H-NMR metabolic profiling to stable isotope tracing in metabolomics, facilitating and complementing the information derived from 2D-NMR experiments and expanding the range of isotopically enriched metabolites detected in cellular extracts.

  5. Degradation of mangrove tissues by arboreal termites (Nasutitermes acajutlae) and their role in the mangrove C cycle (Puerto Rico): Chemical characterization and organic matter provenance using bulk δ13C, C/N, alkaline CuO oxidation-GC/MS, and solid-state 13C NMR

    NASA Astrophysics Data System (ADS)

    Vane, Christopher H.; Kim, Alexander W.; Moss-Hayes, Vicky; Snape, Colin E.; Diaz, Miguel Castro; Khan, Nicole S.; Engelhart, Simon E.; Horton, Benjamin P.

    2013-08-01

    Arboreal termites are wood decaying organisms that play an important role in the first stages of C cycling in mangrove systems. The chemical composition of Rhizophora mangle, Avicennia germinans, and Laguncularia racemosa leaf, stem, and pneumatophore tissues as well as associated sediments was compared to that of nests of the termite Nasutitermes acajutlae. Nests gave δ13C values of -26.1 to -27.2‰ (±0.1) and C/N of 43.3 (±2.0) to 98.6 (±16.2) which were similar to all stem and pneumatophores but distinct from mangrove leaves or sediments. Organic matter processed by termites yielded lignin phenol concentrations (Λ, lambda) that were 2-4 times higher than stem or pneumatophores and 10-20 times higher than that of leaves or sediments, suggesting that the nests were more resistant to biodegradation than the mangrove vegetation source. 13C NMR revealed that polysaccharide content of mangrove tissues (50-69% C) was higher than that of the nests (46-51% C). Conversely, lignin accounted for 16.2-19.6% C of nest material, a threefold increase relative to living mangrove tissues; a similar increase in aromatic methoxyl content was also observed in the nests. Lipids (aliphatic and paraffinic moieties) were also important but rather variable chemical components of all three mangrove species, representing between 13.5 and 28.3% of the C content. Termite nests contained 3.14 Mg C ha-1 which represents approximately 2% of above ground C storage in mangroves, a value that is likely to increase upon burial due to their refractory chemical composition.

  6. A combined DFT - NMR study of cyclic 1,2-diones and methyl ethers of their enols: The power and limitations of the method based on theoretical predictions of 13C NMR chemical shifts

    NASA Astrophysics Data System (ADS)

    Kubicki, Dominik; Gryff-Keller, Adam; Szczeciński, Przemysław

    2012-08-01

    A series of cyclic 1,2-diones and methyl ethers of their enols were investigated by a combined 13C NMR/computational DFT method to establish their preferred solution structures. The optimum molecular geometries and magnetic shielding constants of carbon nuclei were calculated with GIAO DFT [PBE1PBE/6-311++G(2d,p) PCM] method for the investigated molecules allowing for enolization and dynamic conformational equilibriums occurring in the solutions. These compounds served simultaneously as model compounds for testing the effectiveness and limitations of the exploited method of investigating molecular structures based on comparison of the theoretically calculated magnetic shielding constants and experimental 13C NMR chemical shifts. Generally, a very good agreement between experimental and theoretical data was obtained for the investigated group of compounds, which proved the applied level of theory and used methodology to be adequate and should ensure a high accuracy of the 13C NMR chemical shift predictions. Some divergences between the experiment and theory could be interpreted as the results of insufficiencies of the molecular modelling and the effects of neglecting vibrational/librational molecular motions. Furthermore, we report herein an observation of an unexpected 1H NMR spectral pattern for 2,3-dimethoxycyclodeca-1,3-diene (diether of cyclodecadione dienol), which was interpreted to be caused by the slow (in NMR time scale) enantiomerization of this molecule which preferentially assumes a chiral conformation.

  7. Applications of 1H-NMR to Biodiesel Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel is an alternative diesel fuel derived from vegetable oils, animal fats, or used cooking oils. It is produced by reacting these materials with an alcohol in the presence of a catalyst to give the corresponding mono-alkyl esters. 1H-NMR is a routine analytical method that has been used for...

  8. Following Glycolysis Using 13C NMR: An Experiment Adaptable to Different Undergraduate Levels

    NASA Astrophysics Data System (ADS)

    Mega, T. L.; Carlson, C. B.; Cleary, D. A.

    1997-12-01

    This paper describes a laboratory exercise where the glycolysis of [1-13C] glucose under anaerobic conditions was followed using 13C NMR spectroscopy. The exercise is described in terms of its suitability for a variety of different undergraduate levels, although the emphasis in this paper is on its use in a n advanced chemistry laboratory course. The kinetics of the loss of glucose and the production of ethanol were investigated and found not to fit simple first or second order kinetics. In addition, the relative reaction rates of the two anomeric forms of glucose were analyzed, and it was determined that the a anomeric form reacted faster than the β anomeric form. Using proton-coupled 13C NMR, some of the metabolites were identified including ethanol (major) and glycerol (minor). Reaction and spectroscopic details are included.

  9. Characterization of covalent protein conjugates using solid-state sup 13 C NMR spectroscopy

    SciTech Connect

    Garbow, J.R.; Fujiwara, Hideji; Sharp, C.R.; Logusch, E.W. )

    1991-07-23

    Cross-polarization magic-angle spinning (CPMAS) {sup 13}C NMR spectroscopy has been used to characterize covalent conjugates of alachlor, an {alpha}-chloroacetamide hapten, with glutathione (GSH) and bovine serum albumin (BSA). The solid-state NMR method demonstrates definitively the covalent nature of these conjugates and can also be used to characterize the sites of hapten attachment to proteins. Three different sites of alachlor binding are observed in the BSA system. Accurate quantitation of the amount of hapten covalently bound to GSH and BSA is reported. The solid-state {sup 13}C NMR technique can easily be generalized to study other small molecule/protein conjugates and can be used to assist the development and refinement of synthetic methods needed for the successful formation of such protein alkylation products.

  10. (1)H-(13)C NMR-Based Profiling of Biotechnological Starch Utilization.

    PubMed

    Sundekilde, Ulrik K; Meier, Sebastian

    2016-10-04

    Starch is used in food- and nonfood applications as a renewable and degradable source of carbon and energy. Insight into the chemical detail of starch degradation remains challenging as the starch constituents amylose and amylopectin are homopolymers. We show that considerable molecular detail of starch fragmentation can be obtained from multivariate analysis of spectral features in optimized (1)H-(13)C NMR spectroscopy of starch fragments to identify relevant features that distinguish processes in starch utilization. As a case study, we compare the profiles of starch fragments in commercial beer samples. Spectroscopic profiles of homooligomeric starch fragments can be excellent indicators of process conditions. In addition, differences in the structure and composition of starch fragments have predictive value for downstream process output such as ethanol production from starch. Thus, high-resolution (1)H-(13)C NMR spectroscopic profiles of homooligomeric fragment mixtures in conjunction with chemometric methods provide a useful addition to the analytical chemistry toolbox of biotechnological starch utilization.

  11. (13)C-NMR Spectral Data of Alkaloids Isolated from Psychotria Species (Rubiaceae).

    PubMed

    Carvalho Junior, Almir Ribeiro de; Vieira, Ivo Jose Curcino; Carvalho, Mario Geraldo de; Braz-Filho, Raimundo; S Lima, Mary Anne; Ferreira, Rafaela Oliveira; José Maria, Edmilson; Oliveira, Daniela Barros de

    2017-01-11

    The genus Psychotria (Rubiaceae) comprises more than 2000 species, mainly found in tropical and subtropical forests. Several studies have been conducted concerning their chemical compositions, showing that this genus is a potential source of alkaloids. At least 70 indole alkaloids have been identified from this genus so far. This review aimed to compile (13)C-NMR data of alkaloids isolated from the genus Psychotria as well as describe the main spectral features of different skeletons.

  12. Quantifying the chemical composition of soil organic carbon with solid-state 13C NMR

    NASA Astrophysics Data System (ADS)

    Baldock, J. A.; Sanderman, J.

    2011-12-01

    The vulnerability of soil organic carbon (SOC) to biological decomposition and mineralisation to CO2 is defined at least partially by its chemical composition. Highly aromatic charcoal-like SOC components are more stable to biological decomposition than other forms of carbon including cellulose. Solid-state 13C NMR has gained wide acceptance as a method capable of defining SOC chemical composition and mathematical fitting processes have been developed to estimate biochemical composition. Obtaining accurate estimates depends on an ability to quantitatively detect all carbon present in a sample. Often little attention has been paid to defining the proportion of organic carbon present in a soil that is observable in solid-state 13C NMR analyses of soil samples. However, if such data is to be used to inform carbon cycling studies, it is critical that quantitative assessments of SOC observability be undertaken. For example, it is now well established that a significant discrimination exists against the detection of the low proton content polyaromatic structures typical of charcoal using cross polarisation 13C NMR analyses. Such discrimination does not exist where direct polarisation analyses are completed. In this study, the chemical composition of SOC as defined by cross polarisation and direct polarisation13C NMR analyses will be compared for Australian soils collected from under a diverse range of agricultural managements and climatic conditions. Results indicate that where significant charcoal C contents exist, it is highly under-represented in the acquired CP spectra. For some soils, a discrimination against alkyl carbon was also evident. The ability to derive correction factors to compensate for such discriminations will be assessed and presented.

  13. Detection of human muscle glycogen by natural abundance /sup 13/C NMR

    SciTech Connect

    Avison, M.J.; Rothman, D.L.; Nadel, E.; Shulman, R.G.

    1988-03-01

    Natural abundance /sup 13/C nuclear magnetic resonance spectroscopy was used to detect signals from glycogen in the human gastrocnemius muscle. The reproducibility of the measurement was demonstrated, and the ability to detect dynamic changes was confirmed by measuring a decrease in muscle glycogen levels after exercise and its subsequent repletion. Single frequency gated /sup 1/H decoupling was used to obtain decoupled natural abundance /sup 13/C NMR spectra of the C-1 position of muscle glycogen.

  14. Computer-assisted structural analysis of regular glycopolymers on the basis of 13C NMR data.

    PubMed

    Toukach, F V; Shashkov, A S

    2001-09-28

    A computer-assisted approach to the prediction of the primary structures of regular glycopolymers is described. The analysis is based on comparing the calculated 13C NMR spectra of all the possible structures of the repeating unit (for the given monomeric composition) to an experimental 13C NMR spectrum. The spectra generation is based on the spectral database containing information on the 13C chemical shifts of monomers, di- and trimeric fragments. If the required data are missing from this database, the special database for average glycosylation effects is used. The analysis reveals those structures with the calculated 13C NMR spectrum most close to observed. The structures of repeating units of any topology containing up to six residues linked by glycosidic, amidic or phospho-diester bridges can be predicted. Unambiguous selection of the proper structure from the output list of possible structures may require additional experimental data. Testing the created program and databases on bacterial polysaccharides and their derivatives containing up to three non-sugar residues (alditols, amino acids, phosphate groups etc.) per repeating unit revealed the good convergence of prediction with independently obtained structural data.

  15. Density functional theory study of (13)C NMR chemical shift of chlorinated compounds.

    PubMed

    Li, Songqing; Zhou, Wenfeng; Gao, Haixiang; Zhou, Zhiqiang

    2012-02-01

    The use of the standard density functional theory (DFT) leads to an overestimation of the paramagnetic contribution and underestimation of the shielding constants, especially for chlorinated carbon nuclei. For that reason, the predictions of chlorinated compounds often yield too high chemical shift values. In this study, the WC04 functional is shown to be capable of reducing the overestimation of the chemical shift of Cl-bonded carbons in standard DFT functionals and to show a good performance in the prediction of (13)C NMR chemical shifts of chlorinated organic compounds. The capability is attributed to the minimization of the contributions that intensively increase the chemical shift in the WC04. Extensive computations and analyses were performed to search for the optimal procedure for WC04. The B3LYP and mPW1PW91 standard functionals were also used to evaluate the performance. Through detailed comparisons between the basis set effects and the solvent effects on the results, the gas-phase GIAO/WC04/6-311+G(2d,p)//B3LYP/6-31+G(d,p) was found to be specifically suitable for the prediction of (13)C NMR chemical shifts of chlorides in both chlorinated and non-chlorinated carbons. Further tests with eight molecules in the probe set sufficiently confirmed that WC04 was undoubtedly effective for accurately predicting (13) C NMR chemical shifts of chlorinated organic compounds.

  16. 13C NMR studies of the molecular dynamics of chlorpromazine in solution

    NASA Astrophysics Data System (ADS)

    Sakamoto, Yohko; Ishii, Tomoko; Kurokawa, Noriko; Aoki, Toshikazu; Ohshima, Shigeru

    1996-02-01

    The optimum structure, which is expected to lead to biological activity, of chlorpromazine hydrochloride salt (compound ( I)) in solution was determined on the basis of NMR data and molecular orbital calculations; compound ( I) favours a bent structure in which the side-chain tilts toward the chlorinated benzene ring. The molecular mobility of compound ( I) in CDCl 3 and D 2O was also examined on the basis of 13C NMR spin-lattice relaxation time ( T1). T1 depends on the magnetic field strength and the solvent. The dependence indicates that the molecular mobility of compound ( I) is larger in D 2O than in CDCl 3

  17. Conformational studies by 1H and 13C NMR of lisinopril

    NASA Astrophysics Data System (ADS)

    Sakamoto, Yohko; Ishi, Tomoko

    1993-10-01

    Lisinopril, N-N-[( s-1-carboxy-3-phenylpropyl]- L-lysyl- L-proline) (MK-521), is an inhibitor of angiotensin-converting enzyme and a new drug for the treatment of hypertension. 1H and 13C NMR studies have shown that the s-cis equilibrium about the amide bond is strongly dependent on the configuration of the chiral centres. Vicinal coupling constants of stereochemical significance were obtained in deuterated solvent using NMR techniques. Comparison with values calculated for lisinopril using potential energy calculations and NMR show that lisinopril exists in preferred optimum conformation in solution.

  18. 1H and 13C NMR study on some substituted azolidine derivatives

    NASA Astrophysics Data System (ADS)

    Cerioni, Giovanni; Cristiani, Franco; Devillanova, Francesco A.; Diaz, Angelo; Verani, Gaetano

    The 1H and 13C NMR spectra carried out on R overlineN·CH 2·CH 2·X·C O (where for R = H, X = NH, NMe, NEt, CH 2, S, O; for R = Me, X = NMe, CH 2; for R = Et, X = NEt) are reported. The comparison of these results with those obtained for the thionic and selonic isologues shows that sulphur and selenium have a greater deshielding effect on the ring than oxygen. The resonance of the carbons not involved in the π system have been correlated with the σ charges calculated by the DEL RE method.

  19. High Resolution Solid State 13C NMR Spectroscopy of Sporopollenins from Different Plant Taxa

    PubMed Central

    Guilford, William J.; Schneider, Diane M.; Labovitz, Jeffrey; Opella, Stanley J.

    1988-01-01

    The extremely chemically resistant component of the cell wall of spores, pollens, and some microorganisms, sporopollenin, is generally accepted to be derived from carotenoids or carotenoid esters. However, we report here that 13C NMR analyses of sporopollenin from several sources shows that this widely held view is incorrect, with one possible exception. Sporopollenin is not a unique substance but rather a series of related biopolymers derived from largely saturated precursors such as fatty acids. The biopolymers contain widely varying amounts of oxygen in the form of ether, hydroxyl, carboxylic acid, ester, and ketone groups. PMID:16665854

  20. Conformational evaluation and detailed 1H and 13C NMR assignments of eremophilanolides.

    PubMed

    Burgueño-Tapia, Eleuterio; Hernández, Luis R; Reséndiz-Villalobos, Adriana Y; Joseph-Nathan, Pedro

    2004-10-01

    Extensive application of 1D and 2D NMR methodology, combined with molecular modeling, allowed the complete 1H and 13C NMR assignments of eremophilanolides from Senecio toluccanus. Comparison of the experimental 1H, 1H coupling constant values with those generated employing a generalized Karplus-type relationship, using dihedral angles extracted from MMX and DFT calculations, revealed that the epoxidized eremophilanolides 1 and 2 show conformational rigidity at room temperature, whereas molecules 3-6, containing an isolated double bond, are conformationally mobile.

  1. The 1H NMR Profile of Healthy Dog Cerebrospinal Fluid

    PubMed Central

    Musteata, Mihai; Nicolescu, Alina; Solcan, Gheorghe; Deleanu, Calin

    2013-01-01

    The availability of data for reference values in cerebrospinal fluid for healthy humans is limited due to obvious practical and ethical issues. The variability of reported values for metabolites in human cerebrospinal fluid is quite large. Dogs present great similarities with humans, including in cases of central nervous system pathologies. The paper presents the first study on healthy dog cerebrospinal fluid metabolomic profile using 1H NMR spectroscopy. A number of 13 metabolites have been identified and quantified from cerebrospinal fluid collected from a group of 10 mix breed healthy dogs. The biological variability as resulting from the relative standard deviation of the physiological concentrations of the identified metabolites had a mean of 18.20% (range between 9.3% and 44.8%). The reported concentrations for metabolites may be used as normal reference values. The homogeneity of the obtained results and the low biologic variability show that the 1H NMR analysis of the dog’s cerebrospinal fluid is reliable in designing and interpreting clinical and therapeutic trials in dogs with central nervous system pathologies. PMID:24376499

  2. Metabolomic insight into soy sauce through (1)H NMR spectroscopy.

    PubMed

    Ko, Bong-Kuk; Ahn, Hyuk-Jin; van den Berg, Frans; Lee, Cherl-Ho; Hong, Young-Shick

    2009-08-12

    Soy sauce, a well-known seasoning in Asia and throughout the world, consists of many metabolites that are produced during fermentation or aging and that have various health benefits. However, their comprehensive assessment has been limited due to targeted or instrumentally specific analysis. This paper presents for the first time a metabolic characterization of soy sauce, especially that aged up to 12 years, to obtain a global understanding of the metabolic variations through (1)H NMR spectroscopy coupled with multivariate pattern recognition techniques. Elevated amino acids and organic acids and the consumption of carbohydrate were associated with continuous involvement of microflora in aging for 12 years. In particular, continuous increases in the levels of betaine were found during aging for up to 12 years, demonstrating that microbial- or enzyme-related metabolites were also coupled with osmotolerant or halophilic bacteria present during aging. This work provides global insights into soy sauce through a (1)H NMR-based metabolomic approach that enhances the current understanding of the holistic metabolome and allows assessment of soy sauce quality.

  3. Methylation patterns of aquatic humic substances determined by 13C NMR spectroscopy

    USGS Publications Warehouse

    Thorn, K.A.; Steelink, C.; Wershaw, R. L.

    1987-01-01

    13C NMR spectroscopy is used to examine the hydroxyl group functionality of a series of humic and fulvic acids from different aquatic environments. Samples first are methylated with 13C-labeled diazomethane. The NMR spectra of the diazomethylated samples allow one to distinguish between methyl esters of carboxylic acids, methyl ethers of phenolic hydroxyls, and methyl ethers of phenolic hydroxyls adjacent to two substituents. Samples are then permethylated with 13C-labeled methyl iodide/NaH. 13C NMR spectra of permethylated samples show that a significant fraction of the hydroxyl groups is not methylated with diazomethane alone. In these spectra methyl ethers of carbohydrate and aliphatic hydroxyls overlap with methyl ethers of phenolic hydroxyls. Side reactions of the methyltion procedure including carbon methylation in the CH3I/NaH procedure, are also examined. Humic and fulvic acids from bog, swamp, groundwater, and lake waters showssome differences in their distribution of hydroxyl groups, mainly in the concentrations of phenolic hydroxyls, which may be attributed to their different biogeochemical origins. ?? 1987.

  4. A predictive tool for assessing (13)C NMR chemical shifts of flavonoids.

    PubMed

    Burns, Darcy C; Ellis, David A; March, Raymond E

    2007-10-01

    Herein are presented the (1)H and (13)C NMR data for seven monohydroxyflavones (3-, 5-, 6-, 7-, 2'-, 3'-, and 4'-hydroxyflavone), five dihydroxyflavones (3,2'-, 3,3'-, 3,4'-, 3,6-, 2',3'-dihydroxyflavone), a trihydroxyflavone (apigenin; 5,7,4'-trihydroxyflavone), a tetrahydroxyflavone (luteolin; 5,7,3',4'-tetrahydroxyflavone), and three glycosylated hydroxyflavones (orientin; luteolin-6C-beta-D-glucoside, homoorientin; luteolin-8C-beta-D-glucoside, vitexin; apigenin-8C-beta-D-glucoside). When these NMR spectra are compared, it is possible to assess the impact of flavone modification and to elucidate detailed structural and electronic information for these flavonoids. A simple predictive tool for assigning flavonoid (13)C chemical shifts, which is based on the cumulative differences between the monohydroxyflavones and flavone (13)C chemical shifts, is demonstrated. The tool can be used to accurately predict (13)C flavonoid chemical shifts and it is expected to be useful for rapid assessment of flavonoid (13)C NMR spectra and for assigning substitution patterns in newly isolated flavonoids.

  5. Characterisation of pitch fractions by quantitative solid state {sup 13}C NMR

    SciTech Connect

    Andresen, J.M.; Dennison, P.R.; Maroto-Valer, M.M.

    1994-12-31

    Thermal and other pretreatments of pitch fractions are being widely investigated as a means to increase the extent of mesophase formation in relation to the production of high performance carbons. The structural changes that occur can be assessed using carbon skeletal parameters but, although solid state {sup 13}C NMR has been used for this purpose, the quantitative reliability of the technique has still to be established for pitch fractions. It was demonstrated previously that, as for coals, cross-polarisation (CP) can vastly underestimate quaternary aromatic carbon concentrations. A combination of a low magnetic field strength to avoid problems with spinning sidebands and the simple Bloch decay or single pulse excitation (SPE) technique is now generally recognised as offering the most satisfactory approach for obtaining quantitative {sup 13}C NMR results for coals and related materials. In this study, single pulse excitation (SPE) and associated relaxation measurements have been conducted at low field on coal-derived pitches and their toluene-insoluble (TI) fractions, together with a biomass-derived pitch and the results compared with those from CP.

  6. Calculation of the 13C NMR shieldings of the C0 2 complexes of aluminosilicates

    NASA Astrophysics Data System (ADS)

    Tossell, J. A.

    1995-04-01

    13C NMR shieldings have been calculated using the random-phase-approximation, localized-orbital local-origins version of ab initio coupled Hartree-Fuck perturbation theory for CO 2 and and for several complexes formed by the reaction of CO 2 with molecular models for aluminosilicate glasses, H 3TOT'H3 3-n, T,T' = Si,Al. Two isomeric forms of the CO 2-aluminosilicate complexes have been considered: (1) "CO 2-like" complexes, in which the CO 2 group is bound through carbon to a bridging oxygen and (2) "CO 3-like" complexes, in which two oxygens of a central CO 3 group form bridging bonds to the two TH 3 groups. The CO 2-like isomer of CO 2-H 3SiOSiH 3 is quite weakly bonded and its 13C isotropic NMR shielding is almost identical to that in free CO 2. As Si is progressively replaced by Al in the - H terminated aluminosilicate model, the CO 2-like isomers show increasing distortion from the free CO 2 geometry and their 13C NMR shieldings decrease uniformly. The calculated 13C shielding value for H 3AlO(CO 2)AlH 3-2 is only about 6 ppm larger than that calculated for point charge stabilized CO 3-2. However, for a geometry of H 3SiO(CO 2) AlH 3-1, in which the bridging oxygen to C bond length has been artificially increased to that found in the - OH terminated cluster (OH) 3SiO(CO 2)Al(OH) 3-1, the calculated 13C shielding is almost identical to that for free CO 2. The CO 3-like isomers of the CO 2-aluminosili-cate complexes show carbonate like geometries and 13C NMR shieldings about 4-9 ppm larger than those of carbonate for all T,T' pairs. For the Si,Si tetrahedral atom pair the CO 2-like isomer is more stable energetically, while for the Si,Al and Al,Al cases the CO 3-like isomer is more stable. Addition of Na + ions to the CO 3-2 or H 3AlO(CO 2)AlH 3-2 complexes reduces the 13C NMR shieldings by about 10 ppm. Complexation with either Na + or CO 2 also reduces the 29Si NMR shieldings of the aluminosilicate models, while the changes in 27Al shielding with Na + or CO 2

  7. Complete (1)H and (13)C NMR chemical shift assignments of mono-, di-, and trisaccharides as basis for NMR chemical shift predictions of polysaccharides using the computer program casper.

    PubMed

    Roslund, Mattias U; Säwén, Elin; Landström, Jens; Rönnols, Jerk; Jonsson, K Hanna M; Lundborg, Magnus; Svensson, Mona V; Widmalm, Göran

    2011-08-16

    The computer program casper uses (1)H and (13)C NMR chemical shift data of mono- to trisaccharides for the prediction of chemical shifts of oligo- and polysaccharides. In order to improve the quality of these predictions the (1)H and (13)C, as well as (31)P when applicable, NMR chemical shifts of 30 mono-, di-, and trisaccharides were assigned. The reducing sugars gave two distinct sets of NMR resonances due to the α- and β-anomeric forms. In total 35 (1)H and (13)C NMR chemical shift data sets were obtained from the oligosaccharides. One- and two-dimensional NMR experiments were used for the chemical shift assignments and special techniques were employed in some cases such as 2D (1)H,(13)C-HSQC Hadamard Transform methodology which was acquired approximately 45 times faster than a regular t(1) incremented (1)H,(13)C-HSQC experiment and a 1D (1)H,(1)H-CSSF-TOCSY experiment which was able to distinguish spin-systems in which the target protons were only 3.3Hz apart. The (1)H NMR chemical shifts were subsequently refined using total line-shape analysis with the PERCH NMR software. The acquired NMR data were then utilized in the casper program (http://www.casper.organ.su.se/casper/) for NMR chemical shift predictions of the O-antigen polysaccharides from Klebsiella O5, Shigella flexneri serotype X, and Salmonella arizonae O62. The data were compared to experimental data of the polysaccharides from the two former strains and the lipopolysaccharide of the latter strain showing excellent agreement between predicted and experimental (1)H and (13)C NMR chemical shifts.

  8. Interactions of calcium nitrate with pyranosides in water: A 13C NMR study

    NASA Astrophysics Data System (ADS)

    Zhuo, Kelei; Wang, Yaping; Zhao, Yang; Liu, Qian; Wang, Jianji

    2008-11-01

    The 13C NMR spectra of methyl α- and β- D-galactopyranosides, and methyl α- and β- D-glucopyranosides were recorded and show that the Δ( δC-4) values for methyl α- and β- D-galactopyranosides increase most rapidly, whereas those for methyl α- and β- D-glucopyranosides vary hardly with increasing molality of calcium nitrate. It can be concluded that ax-OH-4 interacts more strongly with Ca 2+ than eq-OH-4 group, namely, the Ca 2+ ion interaction with ax-OH-4 leads to a stronger deshielding of the C-4 atom. Compared with other C atoms, the chemical shifts of both C-1 and C-5 atoms in these two types of glycosides decrease relatively rapidly as molality of calcium nitrate increases, indicating that the nitrate ion attractions for these glycosides cause a relatively strong enhancing shielding effect of C-1 and C-5 atoms.

  9. 15N and13C NMR investigation of hydroxylamine-derivatized humic substances

    USGS Publications Warehouse

    Thorn, K.A.; Arterburn, J.B.; Mikita, M.A.

    1992-01-01

    Five fulvic and humic acid samples of diverse origins were derivatized with 15N-labeled hydroxylamine and analyzed by liquid-phase 15N NMR spectrometry. The 15N NMR spectra indicated that hydroxylamine reacted similarly with all samples and could discriminate among carbonyl functional groups. Oximes were the major derivatives; resonances attributable to hydroxamic acids, the reaction products of hydroxylamine with esters, and resonances attributable to the tautomeric equilibrium position between the nitrosophenol and monoxime derivatives of quinones, the first direct spectroscopic evidence for quinones, also were evident. The 15N NMR spectra also suggested the presence of nitriles, oxazoles, oxazolines, isocyanides, amides, and lactams, which may all be explained in terms of Beckmann reactions of the initial oxime derivatives. INEPT and ACOUSTIC 15N NMR spectra provided complementary information on the derivatized samples. 13C NMR spectra of derivatized samples indicated that the ketone/quinone functionality is incompletely derivatized with hydroxylamine. ?? 1991 American Chemical Society.

  10. A 13C-NMR study of exopolysaccharide synthesis in Rhizobium meliloti Su47 strain

    NASA Astrophysics Data System (ADS)

    Tavernier, P.; Portais, J.-C.; Besson, I.; Courtois, J.; Courtois, B.; Barbotin, J.-N.

    1998-02-01

    Metabolic pathways implied in the synthesis of succinoglycan produced by the Su47 strain of R. meliloti were evaluated by 13C-NMR spectroscopy after incubation with [1{-}13C] or [2{-}13C] glucose. The biosynthesis of this polymer by R. meliloti from glucose occurred by a direct polymerisation of the introduced glucose and by the pentose phosphate pathway. Les voies métaboliques impliquées dans la synthèse du succinoglycane produit par la souche Su47 de R. meliloti ont été évaluées par la spectroscopie de RMN du carbone 13 après incubation des cellules avec du [1{-}13C] ou [2{-}13C] glucose. La biosynthèse de ce polymère à partir du glucose se produit par polymérisation directe du glucose et par la voie des pentoses phosphate.

  11. /sup 13/C NMR studies of the molecular flexibility of antidepressants

    SciTech Connect

    Munro, S.L.; Andrews, P.R.; Craik, D.J.; Gale, D.J.

    1986-02-01

    The solution dynamics of a series of clinically potent antidepressants have been investigated by measuring /sup 13/C NMR relaxation parameters. Correlation times and internal motional rates were calculated from spin-lattice relaxation times and nuclear Overhauser effects for the protonated carbons in mianserin, imipramine-like antidepressants, and amitriptyline-like antidepressants. These data were interpreted in terms of overall molecular tumbling, internal rotations, and inherent flexibility of these structures. Of particular interest was the conformational variability of the tricyclic nucleus of the tricyclic antidepressants, where the data indicated a fivefold difference in mobility of the dimethylene bridge of imipramine-like antidepressants relative to amitriptyline-like compounds. The implications of such a difference in internal motions is discussed in relation to previous NMR studies and to the reported differences in pharmacological activity of these antidepressants.

  12. 13C NMR spectroscopy of the insoluble carbon of carbonaceous chondrites

    NASA Technical Reports Server (NTRS)

    Cronin, J. R.; Pizzarello, S.; Frye, J. S.

    1987-01-01

    13C NMR spectra have been obtained of the insoluble carbon residues resulting from HF-digestion of three carbonaceous chondrites, Orgueil (C1), Murchison (CM2), and Allende (CV3). Spectra obtained using the cross polarization magic-angle spinning technique show two major features attributable respectively to carbon in aliphatic/olefinic structures. The spectrum obtained from the Allende sample was weak, presumably as a consequence of its low hydrogen content. Single pulse excitation spectra, which do not depend on 1H-13C polarization transfer for signal enhancement were also obtained. These spectra, which may be more representative of the total carbon in the meteorite samples, indicate a greater content of carbon in aromatic/olefinic structures. These results suggest that extensive polycyclic aromatic sheets are important structural features of the insoluble carbon of all three meteorites. The Orgueil and Murchison materials contain additional hydrogenated aromatic/olefinic and aliphatic groups.

  13. (1) H and (13) C NMR data on natural and synthetic capsaicinoids.

    PubMed

    Gómez-Calvario, Víctor; Garduño-Ramírez, María Luisa; León-Rivera, Ismael; Rios, María Yolanda

    2016-04-01

    Capsaicinoids are the compounds responsible for the pungency of chili peppers. These substances have attracted the attention of many research groups in recent decades because of their antinociceptive, analgesic, anti-inflammatory, and anti-obesity properties, among others. There are nearly 160 capsaicinoids reported in the literature. Approximately 25 of them are natural products, while the rest are synthetic or semi-synthetic products. A large amount of NMR data for the capsaicinoids is dispersed throughout literature. Therefore, there is a need to organize all this NMR data in a systematic and orderly way. This review summarizes the (1) H and (13) C NMR data on 159 natural and synthetic capsaicinoids, with a brief discussion of some typical and relevant aspects of these NMR data. Copyright © 2015 John Wiley & Sons, Ltd.

  14. 13C-NMR in Iodine and Potassium Intercalated C60 Solid

    NASA Astrophysics Data System (ADS)

    Maniwa, Yutaka; Shibata, Takayuki; Mizoguchi, Kenji; Kume, Kiyoshi; Kikuchi, Koichi; Ikemoto, Isao; Suzuki, Shinzo; Achiba, Yoji

    1992-07-01

    Iodine intercalated C60, I2.29C60, was studied by 13C NMR above 160 K. A sharp NMR signal and a strong temperature-dependent spin-lattice relaxation time, T1, indicated a presence of C60 molecular rotation much higher than 10 kHz at least down to 160 K. No evidence of metallic characteristics was found in the NMR shift (143± 1 ppm) and the T1 (40± 5 sec at room temperature). In K3C60, metallic behavior, T1T˜constant, was observed at the carbon sites between 20 K and 100 K. Electronic density of states at the Fermi level, N(EF), in I2.29C60 was estimated to be smaller than 0.12 of that in K3C60, assuming a relationship between N(EF) and T1T for normal metals.

  15. (1) H and (13) C NMR characterization of new cycloartane triterpenes from Mangifera indica.

    PubMed

    Escobedo-Martínez, Carolina; Concepción Lozada, M; Hernández-Ortega, Simón; Villarreal, María Luisa; Gnecco, Dino; Enríquez, Raúl G; Reynolds, William

    2012-01-01

    From the stem bark of Mangifera indica, seven cycloartane-type secondary metabolites were isolated. Compound 1 has been isolated for the first time from M. indica, whereas compounds 2 (2a and 2b, as an epimeric mixture), 3, and 4 are new triterpenoid-type cycloartanes. Unambiguous (13) C and (1) H NMR assignments for these compounds and the known compounds mangiferonic acid (compound 5), isomangiferolic acid (compound 6), ambolic acid (compound 7), and friedelin (compound 8) are reported; the latter because full NMR data for these compounds are not available in the literature.

  16. Comparison of Kinetic Models for Analysis of Pyruvate-to-Lactate Exchange by Hyperpolarized 13C NMR

    PubMed Central

    Harrison, Crystal; Yang, Chendong; Jindal, Ashish; DeBerardinis, Ralph J.; Hooshyar, M.A.; Merritt, Matthew; Sherry, A. Dean; Malloy, Craig R.

    2012-01-01

    The activity of specific enzyme-catalyzed reactions may be detected in vivo by 13C NMR of hyperpolarized (HP) substrates. The signal from HP substrates and products, acquired over time, have been fit to a number of different mathematical models to determine fluxes, but these models have not been critically compared. In this study, two-pool and three-pool first-order models were constructed to measure flux through lactate dehydrogenase in isolated glioblastoma cells by NMR detection of lactate and pyruvate following addition of hyperpolarized [1-13C]pyruvate. Mass spectrometry (MS) was used to independently monitor 13C enrichment in intra- and extracellular lactate. Six models were evaluated using time dependent pyruvate C2 and lactate C1 HP NMR data acquired by use of selective excitation pulses plus 13C enrichment data from intracellular and extracellular lactate measured by MS. A three-pool bi-directional model provided the most accurate description of pyruvate metabolism in these cells. With computed values for the T1 of pyruvate and lactate as well as the effect of pulsing, the initial flux through lactate dehydrogenase (LDH) was well-determined by both the two-pool bidirectional and unidirectional models when only HP data was available. The three-pool model was necessary to fit the combined data from both MS and HP, but the simpler two-pool exchange model was sufficient to determine the 13C lactate concentration when the lactate appearance was measured only by HP. PMID:22451442

  17. 23Na and 1H NMR Microimaging of Intact Plants

    NASA Astrophysics Data System (ADS)

    Olt, Silvia; Krötz, Eva; Komor, Ewald; Rokitta, Markus; Haase, Axel

    2000-06-01

    23Na NMR microimaging is described to map, for the first time, the sodium distribution in living plants. As an example, the response of 6-day-old seedlings of Ricinus communis to exposure to sodium chloride concentrations from 5 to 300 mM was observed in vivo using 23Na as well as 1H NMR microimaging. Experiments were performed at 11.75 T with a double resonant 23Na-1H probehead. The probehead was homebuilt and equipped with a climate chamber. T1 and T2 of 23Na were measured in the cross section of the hypocotyl. Within 85 min 23Na images with an in-plane resolution of 156 × 156 μm were acquired. With this spatial information, the different types of tissue in the hypocotyl can be discerned. The measurement time appears to be short compared to the time scale of sodium uptake and accumulation in the plant so that the kinetics of salt stress can be followed. In conclusion, 23Na NMR microimaging promises great potential for physiological studies of the consequences of salt stress on the macroscopic level and thus may become a unique tool for characterizing plants with respect to salt tolerance and salt sensitivity.

  18. 23Na and (1)H NMR microimaging of intact plants.

    PubMed

    Olt, S; Krötz, E; Komor, E; Rokitta, M; Haase, A

    2000-06-01

    (23)Na NMR microimaging is described to map, for the first time, the sodium distribution in living plants. As an example, the response of 6-day-old seedlings of Ricinus communis to exposure to sodium chloride concentrations from 5 to 300 mM was observed in vivo using (23)Na as well as (1)H NMR microimaging. Experiments were performed at 11.75 T with a double resonant (23)Na-(1)H probehead. The probehead was homebuilt and equipped with a climate chamber. T(1) and T(2) of (23)Na were measured in the cross section of the hypocotyl. Within 85 min (23)Na images with an in-plane resolution of 156 x 156 micrometer were acquired. With this spatial information, the different types of tissue in the hypocotyl can be discerned. The measurement time appears to be short compared to the time scale of sodium uptake and accumulation in the plant so that the kinetics of salt stress can be followed. In conclusion, (23)Na NMR microimaging promises great potential for physiological studies of the consequences of salt stress on the macroscopic level and thus may become a unique tool for characterizing plants with respect to salt tolerance and salt sensitivity.

  19. Quantitative produced water analysis using mobile 1H NMR

    NASA Astrophysics Data System (ADS)

    Wagner, Lisabeth; Kalli, Chris; Fridjonsson, Einar O.; May, Eric F.; Stanwix, Paul L.; Graham, Brendan F.; Carroll, Matthew R. J.; Johns, Michael L.

    2016-10-01

    Measurement of oil contamination of produced water is required in the oil and gas industry to the (ppm) level prior to discharge in order to meet typical environmental legislative requirements. Here we present the use of compact, mobile 1H nuclear magnetic resonance (NMR) spectroscopy, in combination with solid phase extraction (SPE), to meet this metrology need. The NMR hardware employed featured a sufficiently homogeneous magnetic field, such that chemical shift differences could be used to unambiguously differentiate, and hence quantitatively detect, the required oil and solvent NMR signals. A solvent system consisting of 1% v/v chloroform in tetrachloroethylene was deployed, this provided a comparable 1H NMR signal intensity for the oil and the solvent (chloroform) and hence an internal reference 1H signal from the chloroform resulting in the measurement being effectively self-calibrating. The measurement process was applied to water contaminated with hexane or crude oil over the range 1-30 ppm. The results were validated against known solubility limits as well as infrared analysis and gas chromatography.

  20. 1H NMR Metabolomics Analysis of Glioblastoma Subtypes

    PubMed Central

    Cuperlovic-Culf, Miroslava; Ferguson, Dean; Culf, Adrian; Morin, Pier; Touaibia, Mohamed

    2012-01-01

    Glioblastoma multiforme (GBM) is the most common form of malignant glioma, characterized by unpredictable clinical behaviors that suggest distinct molecular subtypes. With the tumor metabolic phenotype being one of the hallmarks of cancer, we have set upon to investigate whether GBMs show differences in their metabolic profiles. 1H NMR analysis was performed on metabolite extracts from a selection of nine glioblastoma cell lines. Analysis was performed directly on spectral data and on relative concentrations of metabolites obtained from spectra using a multivariate regression method developed in this work. Both qualitative and quantitative sample clustering have shown that cell lines can be divided into four groups for which the most significantly different metabolites have been determined. Analysis shows that some of the major cancer metabolic markers (such as choline, lactate, and glutamine) have significantly dissimilar concentrations in different GBM groups. The obtained lists of metabolic markers for subgroups were correlated with gene expression data for the same cell lines. Metabolic analysis generally agrees with gene expression measurements, and in several cases, we have shown in detail how the metabolic results can be correlated with the analysis of gene expression. Combined gene expression and metabolomics analysis have shown differential expression of transporters of metabolic markers in these cells as well as some of the major metabolic pathways leading to accumulation of metabolites. Obtained lists of marker metabolites can be leveraged for subtype determination in glioblastomas. PMID:22528487

  1. Complete assignments of 1H and 13C NMR data for seven arylnaphthalide lignans from Justicia procumbens.

    PubMed

    Yang, Meihua; Wu, Jun; Cheng, Fan; Zhou, Yuan

    2006-07-01

    Three new arylnaphthalide lignans named 6'-hydroxy justicidin A (1), 6'-hydroxy justicidin B (2) and 6'-hydroxy justicidin C (3) have been isolated from the whole plant of Justicia procumbens, together with four known ones, neojusticin A (4), chinensinaphthol methyl ester (5), isodiphyllin (6) and taiwanin C (7). The complete assignments of 1H and 13C NMR chemical shifts for the new lignans and the 13C NMR chemical shifts for the known lignans were obtained for the first time by means of 2D NMR techniques, including HSQC and HMBC.

  2. Characterization and Comparison of Fast Pyrolysis Bio-oils from Pinewood, Rapeseed Cake, and Wheat Straw Using 13C NMR and Comprehensive GC × GC

    PubMed Central

    2016-01-01

    Fast pyrolysis bio-oils are feasible energy carriers and a potential source of chemicals. Detailed characterization of bio-oils is essential to further develop its potential use. In this study, quantitative 13C nuclear magnetic resonance (13C NMR) combined with comprehensive two-dimensional gas chromatography (GC × GC) was used to characterize fast pyrolysis bio-oils originated from pinewood, wheat straw, and rapeseed cake. The combination of both techniques provided new information on the chemical composition of bio-oils for further upgrading. 13C NMR analysis indicated that pinewood-based bio-oil contained mostly methoxy/hydroxyl (≈30%) and carbohydrate (≈27%) carbons; wheat straw bio-oil showed to have high amount of alkyl (≈35%) and aromatic (≈30%) carbons, while rapeseed cake-based bio-oil had great portions of alkyl carbons (≈82%). More than 200 compounds were identified and quantified using GC × GC coupled to a flame ionization detector (FID) and a time of flight mass spectrometer (TOF-MS). Nonaromatics were the most abundant and comprised about 50% of the total mass of compounds identified and quantified via GC × GC. In addition, this analytical approach allowed the quantification of high value-added phenolic compounds, as well as of low molecular weight carboxylic acids and aldehydes, which exacerbate the unstable and corrosive character of the bio-oil. PMID:27668136

  3. Characterization and Comparison of Fast Pyrolysis Bio-oils from Pinewood, Rapeseed Cake, and Wheat Straw Using (13)C NMR and Comprehensive GC × GC.

    PubMed

    Negahdar, Leila; Gonzalez-Quiroga, Arturo; Otyuskaya, Daria; Toraman, Hilal E; Liu, Li; Jastrzebski, Johann T B H; Van Geem, Kevin M; Marin, Guy B; Thybaut, Joris W; Weckhuysen, Bert M

    2016-09-06

    Fast pyrolysis bio-oils are feasible energy carriers and a potential source of chemicals. Detailed characterization of bio-oils is essential to further develop its potential use. In this study, quantitative (13)C nuclear magnetic resonance ((13)C NMR) combined with comprehensive two-dimensional gas chromatography (GC × GC) was used to characterize fast pyrolysis bio-oils originated from pinewood, wheat straw, and rapeseed cake. The combination of both techniques provided new information on the chemical composition of bio-oils for further upgrading. (13)C NMR analysis indicated that pinewood-based bio-oil contained mostly methoxy/hydroxyl (≈30%) and carbohydrate (≈27%) carbons; wheat straw bio-oil showed to have high amount of alkyl (≈35%) and aromatic (≈30%) carbons, while rapeseed cake-based bio-oil had great portions of alkyl carbons (≈82%). More than 200 compounds were identified and quantified using GC × GC coupled to a flame ionization detector (FID) and a time of flight mass spectrometer (TOF-MS). Nonaromatics were the most abundant and comprised about 50% of the total mass of compounds identified and quantified via GC × GC. In addition, this analytical approach allowed the quantification of high value-added phenolic compounds, as well as of low molecular weight carboxylic acids and aldehydes, which exacerbate the unstable and corrosive character of the bio-oil.

  4. The molecular structure and vibrational, (1)H and (13)C NMR spectra of lidocaine hydrochloride monohydrate.

    PubMed

    Badawi, Hassan M; Förner, Wolfgang; Ali, Shaikh A

    2016-01-05

    The structure, vibrational and NMR spectra of the local anesthetic drug lidocaine hydrochloride monohydrate salt were investigated by B3LYP/6-311G(∗∗) calculations. The lidocaine·HCl·H2O salt is predicted to have the gauche structure as the predominant form at ambient temperature with NCCN and CNCC torsional angles of 110° and -123° as compared to 10° and -64°, respectively in the base lidocaine. The repulsive interaction between the two N-H bonds destabilized the gauche structure of lidocaine·HCl·H2O salt. The analysis of the observed vibrational spectra is consistent with the presence of the lidocaine salt in only one gauche conformation at room temperature. The (1)H and (13)C NMR spectra of lidocaine·HCl·H2O were interpreted by experimental and DFT calculated chemical shifts of the lidocaine salt. The RMSD between experimental and theoretical (1)H and (13)C chemical shifts for lidocaine·HCl·H2O is 2.32 and 8.21ppm, respectively.

  5. (13)C-NMR-Based Metabolomic Profiling of Typical Asian Soy Sauces.

    PubMed

    Kamal, Ghulam Mustafa; Yuan, Bin; Hussain, Abdullah Ijaz; Wang, Jie; Jiang, Bin; Zhang, Xu; Liu, Maili

    2016-09-02

    It has been a strong consumer interest to choose high quality food products with clear information about their origin and composition. In the present study, a total of 22 Asian soy sauce samples have been analyzed in terms of (13)C-NMR spectroscopy. Spectral data were analyzed by multivariate statistical methods in order to find out the important metabolites causing the discrimination among typical soy sauces from different Asian regions. It was found that significantly higher concentrations of glutamate in Chinese red cooking (CR) soy sauce may be the result of the manual addition of monosodium glutamate (MSG) in the final soy sauce product. Whereas lower concentrations of amino acids, like leucine, isoleucine and valine, observed in CR indicate the different fermentation period used in production of CR soy sauce, on the other hand, the concentration of some fermentation cycle metabolites, such as acetate and sucrose, can be divided into two groups. The concentrations of these fermentation cycle metabolites were lower in CR and Singapore Kikkoman (SK), whereas much higher in Japanese shoyu (JS) and Taiwan (China) light (TL), which depict the influence of climatic conditions. Therefore, the results of our study directly indicate the influences of traditional ways of fermentation, climatic conditions and the selection of raw materials and can be helpful for consumers to choose their desired soy sauce products, as well as for researchers in further authentication studies about soy sauce.

  6. A Critical Evaluation of the Quality of Published (13)C NMR Data in Natural Product Chemistry.

    PubMed

    Robien, Wolfgang

    2017-01-01

    Nuclear Magnetic Resonance spectroscopy contributes very efficiently to the structure elucidation process in organic chemistry. Carbon-13 NMR spectroscopy allows direct insight into the skeleton of organic compounds and therefore plays a central role in the structural assignment of natural products. Despite this important contribution, there is no established and well-accepted workflow protocol utilized during the first steps of interpreting spectroscopic data and converting them into structural fragments and then combining them, by considering the given spectroscopic constraints, into a final proposal of structure. The so-called "combinatorial explosion" in the process of structure generation allows in many cases the generation of reasonable alternatives, which are usually ignored during manual interpretation of the measured data leading ultimately to a large number of structural revisions. Furthermore, even when the determined structure is correct, problems may exist such as assignment errors, ignoring chemical shift values, or assigning lines of impurities to the compound under consideration. An extremely large heterogeneity in the presentation of carbon NMR data can be observed, but, as a result of the efficiency and precision of spectrum prediction, the published data can be analyzed in substantial detail.This contribution presents a comprehensive analysis of frequently occurring errors with respect to (13)C NMR spectroscopic data and proposes a straightforward protocol to eliminate a high percentage of the most obvious errors. The procedure discussed can be integrated readily into the processes of submission and peer-reviewing of manuscripts.

  7. Effect of glyphosate on plant cell metabolism. 31P and 13C NMR studies.

    PubMed

    Gout, E; Bligny, R; Genix, P; Tissut, M; Douce, R

    1992-01-01

    The effect of glyphosate (N-phosphonomethyl glycine; the active ingredient of Roundup herbicide) on plant cells metabolism was analysed by 31P and 13C NMR using suspension-cultured sycamore (Acer pseudoplatanus L) cells. Cells were compressed in the NMR tube and perfused with an original arrangement enabling a tight control of the circulating nutrient medium. Addition of 1 mM glyphosate to the nutrient medium triggered the accumulation of shikimate (20-30 mumol g-1 cell wet weight within 50 h) and shikimate 3-phosphate (1-1.5 mumol g-1 cell wet weight within 50 h). From in vivo spectra it was demonstrated that these two compounds were accumulated in the cytoplasm where their concentrations reached potentially lethal levels. On the other hand, glyphosate present in the cytoplasmic compartment was extensively metabolized to yield aminomethylphosphonic acid which also accumulated in the cytoplasm. Finally, the results presented in this paper indicate that although the cell growth was stopped by glyphosate the cell respiration rates and the level of energy metabolism intermediates remained unchanged.

  8. Stability-indicating HPLC method development and structural elucidation of novel degradation products in posaconazole injection by LC-TOF/MS, LC-MS/MS and NMR.

    PubMed

    Yang, Yidi; Zhu, Xi; Zhang, Fei; Li, Wei; Wu, Ying; Ding, Li

    2016-06-05

    Stress testing was carried out under acidic, alkaline, oxidative, thermal and photolytic conditions to evaluate the intrinsic stability of posaconazole injection. A total of four degradation products were detected and the drug was found to be susceptible to oxidative and thermal degradations. Three unknown degradants formed under oxidative stress condition were isolated by preparative HPLC and unambiguously elucidated by LC-TOF/MS, LC-MS/MS, (1)H NMR, (13)C NMR and 2D NMR techniques. Based on the spectrometric and spectroscopic information, these novel degradation products were unequivocally assigned as the N-oxides of posaconazole. Probable mechanisms for the formation of the degradants were proposed. A new and selective HPLC method was developed and validated to separate, detect and quantify all the degradants in posaconazole injection.

  9. 1H and 13C NMR signal assignments of a novel Baeyer-Villiger originated diterpene lactone.

    PubMed

    Vieira, Henriete S; Takahashi, Jacqueline A; Gunatilaka, A A Leslie; Boaventura, Maria Amélia D

    2006-02-01

    A highly rearranged novel dilactone was the single product isolated from Baeyer-Villiger oxidation of a norketone prepared from grandiflorenic acid, a natural kaurane diterpene. The complete 1H and 13C NMR assignment is presented for this novel compound that showed discrete in vitro antibacterial activity.

  10. Mechanisms of humic acids degradation by white rot fungi explored using 1H NMR spectroscopy and FTICR mass spectrometry.

    PubMed

    Grinhut, Tzafrir; Hertkorn, Norbert; Schmitt-Kopplin, Philippe; Hadar, Yitzhak; Chen, Yona

    2011-04-01

    Enzymatic activities involved in decay processes of natural aromatic macromolecules, such as humic acids (HA) and lignin by white rot fungi, have been widely investigated. However, the physical and chemical analysis of degradation products of these materials has not been intensively explored. Fourier transform cyclotron resonance mass spectrometry (FTICR MS) and 1H NMR as well as CHNOS and size exclusion chromatography were employed to study the mechanisms of HA degradation by Trametes sp. M23 and Phanerochaete sp. Y6. Size exclusion chromatography analyses demonstrate and provide evidence for HA breakdown into low MW compounds. The 1H NMR analysis revealed oxidation, a decrease in the aromatic content, and an indication of demethylation of the HA during biodegradation. Evidence for oxidation was also obtained using CHNOS. Analysis of FTICR MS results using a new software program developed by our group (David Mass Sort) revealed consecutive series of masses suggesting biochemical degradation trends such as oxidation, aromatic cleavage, and demethylation. These results are in agreement with the 1H NMR analysis and with the suggested role of the ligninolytic system leading to HA degradation.

  11. 13C-NMR relation study of heparin-disaccharide interactions with tripeptides GRG and GKG.

    PubMed Central

    Mikhailov, D; Mayo, K H; Pervin, A; Linhardt, R J

    1996-01-01

    Heparin is a polydisperse sulphated copolymer consisting mostly of 1-->4 linked glucosamine and uronic acid residues, i.e. 2-deoxy-2-sulphamido-D-glucopyranose 6-sulphate and L-idopyranosyluronic acid 2-sulphate. 13C NMR has been used to study the interactions of heparinase-derived and purified heparin disaccharide with N- and C-terminally-blocked tripeptides GRG and GKG. Titration of the disaccharide with peptide indicates that GRG binds the disaccharide more strongly than does GKG, with interactions in either case being stronger at uronate ring positions. In the presence of GRG, a carboxylate pKa depression suggests electrostatic interactions between the arginine guanidinium group and the uronate carboxylate group. 13C relaxation data have been acquired for all disaccharide and peptide carbons in the presence and absence of GRG and GKG. 13C relaxation rates for the disaccharide are significantly faster in the presence of peptide, especially with GRG. Analysis of these relaxation data has been done in terms of molecular diffusion constants, D [symbol: see text] and D parallel, and an angle alpha between D parallel and a molecular frame defined by the moment of inertia tensor calculated for an internally rigid disaccharide. Disaccharide conformational space in these calculations has been sampled for both uronate half-chair forms (2H1 and 1H2) and over a range of glycosidic bond angles defined by motional order parameters and inter-residue nuclear Overhauser effects (+/- 30 degree from the average). In the absence of peptide, the ratio D [symbol: see text] /D parallel falls between 0.4 and 0.7; therefore molecular diffusion occurs preferentially about D parallel, which runs through both disaccharide rings. In the presence of peptide, D [symbol: see text] /D parallel is decreased, indicating that GRG is oriented along D parallel and proximal to the uronic acid ring. A model for this is shown. PMID:8615813

  12. Density Functional Studies of the 13C NMR Chemical Shifts in Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Zurek, Eva; Autschbach, Jochen

    2007-12-01

    Density functional theory has been used to compute the electronic structure and 13C NMR chemical shifts of finite (9,0) single-walled carbon nanotubes (SWNTs) capped with fullerene hemispheres and with hydrogen atoms. The chemical shifts and HOMO-LUMO gaps were found to be dependent upon the mode of capping. The shifts of semiconducting and metallic tubes were estimated as being around 130 ppm and 141 ppm, respectively. Periodic boundary calculations on infinite zigzag (n,0) SWNTs with 7⩽n⩽17 were performed. These entities can be characterized by a family index, λ = mod(n,3), and the chemical shifts can be fitted well by a function inversely proportional to the diameter of the tube and proportional to a constant which depends on the nanotube family. Direct comparison of the molecular and periodic approaches can be made if benzene is used as the internal reference. Such a comparison indicates that capping may have a strong effect on the computed properties. Calculations on infinite zigzag (7⩽n⩽10) amine functionalized SWNTs have been performed. The functional group may react with a C-C bond which is parallel or diagonal to the tube axis and both sites have been considered. The shifts of the carbons directly attached to the group are sensitive to the bond which has been functionalized and may therefore be used to discriminate between the two products. Functionalization induces a significant line broadening of the NMR signals but it does not dramatically change the average shift of the unfunctionalized SWNT carbons.

  13. 13C NMR study of halogen bonding of haloarenes: measurements of solvent effects and theoretical analysis.

    PubMed

    Glaser, Rainer; Chen, Naijun; Wu, Hong; Knotts, Nathan; Kaupp, Martin

    2004-04-07

    Solvent effects on the NMR spectra of symmetrical (X = F (1), X = Cl (2), X = Br (3), X = I (4), X = NO2 (5), X = CN (6)) and unsymmetrical (X = I, Y = MeO (7), Y = PhO (8)) para-disubstituted acetophenone azines X-C6H4-CMe=N-N=CMe-C6H4-Y and of models X-C6H4-CMe=N-Z (X = I, Z = H (9), Z = NH2 (10)), 4-iodoacetophenone (11), and iodobenzene (12) were measured in CDCl(3), DMSO, THF, pyridine, and benzene to address one intramolecular and one intermolecular issue. Solvent effects on the (13)C NMR spectra are generally small, and this finding firmly establishes that the azine bridge indeed functions as a "conjugation stopper," an important design concept in our polar materials research. Since intermolecular halogen bonding of haloarenes do occur in polar organic crystalline materials, the NMR solution data pose the question as to whether the absence of solvent shifts indicates the absence of strong halogen bonding in solution. This question was studied by the theoretical analysis of the DMSO complexes of iodoarenes 4, 9-12, and of iodoacetylene. DFT and MP2 computations show iodine bonding, and characteristic structural and electronic features are described. The nonrelativistic complexation shifts and the change in the spin-orbit induced heavy atom effect of iodine compensate each other, and iodine bonding thus has no apparent effect on Ci in the iodoarenes. For iodides, complexation by DMSO occurs and may or may not manifest itself in the NMR spectra. The absence of complexation shifts in the NMR spectra of halides does not exclude the occurrence of halogen bonding in solution.

  14. Neuroprotective effects of caffeine in MPTP model of Parkinson's disease: A (13)C NMR study.

    PubMed

    Bagga, Puneet; Chugani, Anup N; Patel, Anant B

    2016-01-01

    Parkinson's disease (PD) is a neurodegenerative disorder characterized by degeneration of nigrostriatal dopaminergic neurons with an accompanying neuroinflammation leading to loss of dopamine in the basal ganglia. Caffeine, a well-known A2A receptor antagonist is reported to slow down the neuroinflammation caused by activated microglia and reduce the extracellular glutamate in the brain. In this study, we have evaluated the neuroprotective effect of caffeine in the MPTP model of PD by monitoring the region specific cerebral energy metabolism. Adult C57BL6 mice were treated with caffeine (30 mg/kg, i.p.) 30 min prior to MPTP (25 mg/kg, i.p.) administration for 8 days. The paw grip strength of mice was assessed in order to evaluate the motor function after various treatments. For metabolic studies, mice were infused with [1,6-(13)C2]glucose, and (13)C labeling of amino acids was monitored using ex vivo(1)H-[(13)C]-NMR spectroscopy. The paw grip strength was found to be reduced following the MPTP treatment. The caffeine pretreatment showed significant protection against the reduction of paw grip strength in MPTP treated mice. The levels of GABA and myo-inositol were found to be elevated in the striatum of MPTP treated mice. The (13)C labeling of GluC4, GABAC2 and GlnC4 from [1,6-(13)C2]glucose was decreased in the cerebral cortex, striatum, olfactory bulb, thalamus and cerebellum suggesting impaired glutamatergic and GABAergic neuronal activity and neurotransmission of the MPTP treated mice. Most interestingly, the pretreatment of caffeine maintained the (13)C labeling of amino acids to the control values in cortical, olfactory bulb and cerebellum regions while it partially retained in striatal and thalamic regions in MPTP treated mice. The pretreatment of caffeine provides a partial neuro-protection against severe striatal degeneration in the MPTP model of PD.

  15. Acetate and bicarbonate assimilation and metabolite formation in Chlamydomonas reinhardtii: a 13C-NMR study.

    PubMed

    Singh, Himanshu; Shukla, Manish R; Chary, Kandala V R; Rao, Basuthkar J

    2014-01-01

    Cellular metabolite analyses by (13)C-NMR showed that C. reinhardtii cells assimilate acetate at a faster rate in heterotrophy than in mixotrophy. While heterotrophic cells produced bicarbonate and CO2aq, mixotrophy cells produced bicarbonate alone as predominant metabolite. Experiments with singly (13)C-labelled acetate ((13)CH(3)-COOH or CH(3)-(13)COOH) supported that both the (13)C nuclei give rise to bicarbonate and CO2(aq). The observed metabolite(s) upon further incubation led to the production of starch and triacylglycerol (TAG) in mixotrophy, whereas in heterotrophy the TAG production was minimal with substantial accumulation of glycerol and starch. Prolonged incubation up to eight days, without the addition of fresh acetate, led to an increased TAG production at the expense of bicarbonate, akin to that of nitrogen-starvation. However, such TAG production was substantially high in mixotrophy as compared to that in heterotrophy. Addition of mitochondrial un-coupler blocked the formation of bicarbonate and CO2(aq) in heterotrophic cells, even though acetate uptake ensued. Addition of PSII-inhibitor to mixotrophic cells resulted in partial conversion of bicarbonate into CO2(aq), which were found to be in equilibrium. In an independent experiment, we have monitored assimilation of bicarbonate via photoautotrophy and found that the cells indeed produce starch and TAG at a much faster rate as compared to that in mixotrophy and heterotrophy. Further, we noticed that the accumulation of starch is relatively more as compared to TAG. Based on these observations, we suggest that acetate assimilation in C. reinhardtii does not directly lead to TAG formation but via bicarbonate/CO2(aq) pathways. Photoautotrophic mode is found to be the best growth condition for the production of starch and TAG and starch in C. reinhardtii.

  16. Detection of polyol accumulation in a new ovarian carcinoma cell line, CABA I: a1H NMR study

    PubMed Central

    Ferretti, A; D'Ascenzo, S; Knijn, A; Iorio, E; Dolo, V; Pavan, A; Podo, F

    2002-01-01

    Ovarian carcinomas represent a major form of gynaecological malignancies, whose treatment consists mainly of surgery and chemotherapy. Besides the difficulty of prognosis, therapy of ovarian carcinomas has reached scarce improvement, as a consequence of lack of efficacy and development of drug-resistance. The need of different biochemical and functional parameters has grown, in order to obtain a larger view on processes of biological and clinical significance. In this paper we report novel metabolic features detected in a series of different human ovary carcinoma lines, by 1H NMR spectroscopy of intact cells and their extracts. Most importantly, a new ovarian adenocarcinoma line CABA I, showed strong signals in the spectral region between 3.5 and 4.0 p.p.m., assigned for the first time to the polyol sorbitol (39±11 nmol/106 cells). 13C NMR analyses of these cells incubated with [1-13C]-D-glucose demonstrated labelled-sorbitol formation. The other ovarian carcinoma cell lines (OVCAR-3, IGROV 1, SK-OV-3 and OVCA432), showed, in the same spectral region, intense resonances from other metabolites: glutathione (up to 30 nmol/106 cells) and myo-inositol (up to 50 nmol/106 cells). Biochemical and biological functions are suggested for these compounds in human ovarian carcinoma cells, especially in relation to their possible role in cell detoxification mechanisms during tumour progression. British Journal of Cancer (2002) 86, 1180–1187. DOI: 10.1038/sj/bjc/6600189 www.bjcancer.com © 2002 Cancer Research UK PMID:11953869

  17. Reliability of ^1^H NMR analysis for assessment of lipid oxidation at frying temperatures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The reliability of a method using ^1^H NMR analysis for assessment of oil oxidation at a frying temperature was examined. During heating and frying at 180 °C, changes of soybean oil signals in the ^1^H NMR spectrum including olefinic (5.16-5.30 ppm), bisallylic (2.70-2.88 ppm), and allylic (1.94-2.1...

  18. Metabonomics investigation of human urine after ingestion of green tea with gas chromatography/mass spectrometry, liquid chromatography/mass spectrometry and (1)H NMR spectroscopy.

    PubMed

    Law, Wai Siang; Huang, Pei Yun; Ong, Eng Shi; Ong, Choon Nam; Li, Sam Fong Yau; Pasikanti, Kishore Kumar; Chan, Eric Chun Yong

    2008-08-01

    A method using gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS) and (1)H NMR with pattern recognition tools such as principle components analysis (PCA) was used to study the human urinary metabolic profiles after the intake of green tea. From the normalized peak areas obtained from GC/MS and LC/MS and peak heights from (1)H NMR, statistical analyses were used in the identification of potential biomarkers. Metabolic profiling by GC/MS provided a different set of quantitative signatures of metabolites that can be used to characterize the molecular changes in human urine samples. A comparison of normalized metabonomics data for selected metabolites in human urine samples in the presence of potential overlapping peaks after tea ingestion from LC/MS and (1)H NMR showed the reliability of the current approach and method of normalization. The close agreements of LC/MS with (1)H NMR data showed that the effects of ion suppression in LC/MS for early eluting metabolites were not significant. Concurrently, the specificity of detecting the stated metabolites by (1)H NMR and LC/MS was demonstrated. Our data showed that a number of metabolites involved in glucose metabolism, citric acid cycle and amino acid metabolism were affected immediately after the intake of green tea. The proposed approach provided a more comprehensive picture of the metabolic changes after intake of green tea in human urine. The multiple analytical approach together with pattern recognition tools is a useful platform to study metabolic profiles after ingestion of botanicals and medicinal plants.

  19. Complete assignment of the (1)H and (13)C NMR spectra of cis and trans isonucleoside derivatives of purine with a tetrahydropyran ring.

    PubMed

    Besada, Pedro; Costas, Tamara; Terán, Carmen

    2010-06-01

    (1)H and (13)C NMR chemical shifts of cis and trans isonucleoside analogues of purine in which the furanose moiety is substituted by a tetrahydropyran ring were completely assigned using one- and two-dimensional NMR experiments that include NOE, DEPT, COSY and HSQC. The significant (1)H and (13)C NMR signals differentiating between the cis and trans stereoisomers were compared.

  20. 13C nuclear magnetic resonance data of lanosterol derivatives—Profiling the steric topology of the steroid skeleton via substituent effects on its 13C NMR

    NASA Astrophysics Data System (ADS)

    Dias, Jerry Ray; Gao, Hongwu

    2009-12-01

    The 13C NMR spectra of over 24 tetracyclic triterpenoid derivatives have been structurally analyzed. The 13C NMR chemical shifts allow one to probe the steric topology of the rigid steroid skeleton and inductive effects of its substituents. Use of deuterium labeling in chemical shift assignment and B-ring aromatic terpenoids are also featured.

  1. FT-IR, UV-vis, 1H and 13C NMR spectra and the equilibrium structure of organic dye molecule disperse red 1 acrylate: a combined experimental and theoretical analysis.

    PubMed

    Cinar, Mehmet; Coruh, Ali; Karabacak, Mehmet

    2011-12-01

    This study reports the characterization of disperse red 1 acrylate compound by spectral techniques and quantum chemical calculations. The spectroscopic properties were analyzed by FT-IR, UV-vis, (1)H NMR and (13)C NMR techniques. FT-IR spectrum in solid state was recorded in the region 4000-400 cm(-1). The UV-vis absorption spectrum of the compound that dissolved in methanol was recorded in the range of 200-800 nm. The (1)H and (13)C NMR spectra were recorded in CDCl(3) solution. The structural and spectroscopic data of the molecule in the ground state were calculated using density functional theory (DFT) employing B3LYP exchange correlation and the 6-311++G(d,p) basis set. The vibrational wavenumbers were calculated and scaled values were compared with experimental FT-IR spectrum. A satisfactory consistency between the experimental and theoretical spectra was obtained and it shows that the hybrid DFT method is very useful in predicting accurate vibrational structure, especially for high-frequency region. The complete assignments were performed on the basis of the experimental results and total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. Isotropic chemical shifts were calculated using the gauge-invariant atomic orbital (GIAO) method. A study on the electronic properties were performed by timedependent DFT (TD-DFT) and CIS(D) approach. To investigate non linear optical properties, the electric dipole moment μ, polarizability α, anisotropy of polarizability Δα and molecular first hyperpolarizability β were computed. The linear polarizabilities and first hyperpolarizabilities of the studied molecule indicate that the compound can be a good candidate of nonlinear optical materials.

  2. Solid-state 13C NMR and molecular modeling studies of acetyl aleuritolic acid obtained from Croton cajucara Benth

    NASA Astrophysics Data System (ADS)

    da Silva San Gil, Rosane Aguiar; Albuquerque, Magaly Girão; de Alencastro, Ricardo Bicca; da Cunha Pinto, Angelo; do Espírito Santo Gomes, Fabiano; de Castro Dantas, Tereza Neuma; Maciel, Maria Aparecida Medeiros

    2008-08-01

    Solid-state 13C nuclear magnetic resonance ( 13C NMR) with magic-angle spinning (MAS) and with cross-polarization and magic-angle spinning (CP/MAS) spectra, and differential scanning calorimetry (DSC) techniques were used to obtain structural data from a sample of acetyl aleuritolic acid (AAA) extracted from the stem bark of Croton cajucara Benth. (Euphorbiaceae) and recrystallized from acetone. Since solid-state 13C NMR results suggested the presence of more than one molecule in the unitary cell for the AAA, DSC analysis and molecular modeling calculations were used to access this possibility. The absence of phase transition peaks in the DSC spectra and the dimeric models of AAA simulated using the semi-empirical PM3 method are in agreement with that proposal.

  3. 1H-NMR analysis provides a metabolomic profile of patients with multiple sclerosis

    PubMed Central

    Cocco, Eleonora; Murgia, Federica; Lorefice, Lorena; Barberini, Luigi; Poddighe, Simone; Frau, Jessica; Fenu, Giuseppe; Coghe, Giancarlo; Murru, Maria Rita; Murru, Raffaele; Del Carratore, Francesco; Atzori, Luigi

    2015-01-01

    Objective: To investigate the metabolomic profiles of patients with multiple sclerosis (MS) and to define the metabolic pathways potentially related to MS pathogenesis. Methods: Plasma samples from 73 patients with MS (therapy-free for at least 90 days) and 88 healthy controls (HC) were analyzed by 1H-NMR spectroscopy. Data analysis was conducted with principal components analysis followed by a supervised analysis (orthogonal partial least squares discriminant analysis [OPLS-DA]). The metabolites were identified and quantified using Chenomx software, and the receiver operating characteristic (ROC) curves were calculated. Results: The model obtained with the OPLS-DA identified predictive metabolic differences between the patients with MS and HC (R2X = 0.615, R2Y = 0.619, Q2 = 0.476; p < 0.001). The differential metabolites included glucose, 5-OH-tryptophan, and tryptophan, which were lower in the MS group, and 3-OH-butyrate, acetoacetate, acetone, alanine, and choline, which were higher in the MS group. The suitability of the model was evaluated using an external set of samples. The values returned by the model were used to build the corresponding ROC curve (area under the curve of 0.98). Conclusion: NMR metabolomic analysis was able to discriminate different metabolic profiles in patients with MS compared with HC. With the exception of choline, the main metabolic changes could be connected to 2 different metabolic pathways: tryptophan metabolism and energy metabolism. Metabolomics appears to represent a promising noninvasive approach for the study of MS. PMID:26740964

  4. Complete assignments of 1H and 13C NMR data for three new arylnaphthalene lignan from Justicia procumbens.

    PubMed

    Liu, Guorui; Wu, Jun; Si, Jianyong; Wang, Junmei; Yang, Meihua

    2008-03-01

    Three new arylnaphthalene lignans, named neojusticin C (1), procumbenoside C (2) and procumbenoside D (3), have been isolated from the whole plant of Justicia procumbens, together with three known ones, justicidinoside B (4), justicidinoside C (5), and diphyllin-1-O-beta-D-apiofuranoside (6). The complete assignments of 1H and 13C NMR data for three new lignans were first obtained by means of 2D NMR techniques, including HSQC and HMBC.

  5. Near-silence of isothiocyanate carbon in (13)C NMR spectra: a case study of allyl isothiocyanate.

    PubMed

    Glaser, Rainer; Hillebrand, Roman; Wycoff, Wei; Camasta, Cory; Gates, Kent S

    2015-05-01

    (1)H and (13)C NMR spectra of allyl isothiocyanate (AITC) were measured, and the exchange dynamics were studied to explain the near-silence of the ITC carbon in (13)C NMR spectra. The dihedral angles α = ∠(C1-C2-C3-N4) and β = ∠(C2-C3-N4-C5) describe the conformational dynamics (conformation change), and the bond angles γ = ∠(C3-N4-C5) and ε = ∠(N4-C5-S6) dominate the molecular dynamics (conformer flexibility). The conformation space of AITC contains three minima, Cs-M1 and enantiomers M2 and M2'; the exchange between conformers is very fast, and conformational effects on (13)C chemical shifts are small (νM1 - νM2 < 3 ppm). Isotropic chemical shifts, ICS(γ), were determined for sp, sp(x), and sp(2) N-hybridization, and the γ dependencies of δ(N4) and δ(C5) are very large (10-33 ppm). Atom-centered density matrix propagation trajectories show that every conformer can access a large region of the potential energy surface AITC(γ,ε,...) with 120° < γ < 180° and 155° < ε < 180°. Because the extreme broadening of the (13)C NMR signal of the ITC carbon is caused by the structural flexibility of every conformer of AITC, the analysis provides a general explanation for the near-silence of the ITC carbon in (13)C NMR spectra of organic isothiocyanates.

  6. Origin of the conformational modulation of the 13C NMR chemical shift of methoxy groups in aromatic natural compounds.

    PubMed

    Toušek, Jaromír; Straka, Michal; Sklenář, Vladimír; Marek, Radek

    2013-01-24

    The interpretation of nuclear magnetic resonance (NMR) parameters is essential to understanding experimental observations at the molecular and supramolecular levels and to designing new and more efficient molecular probes. In many aromatic natural compounds, unusual (13)C NMR chemical shifts have been reported for out-of-plane methoxy groups bonded to the aromatic ring (~62 ppm as compared to the typical value of ~56 ppm for an aromatic methoxy group). Here, we analyzed this phenomenon for a series of aromatic natural compounds using Density Functional Theory (DFT) calculations. First, we checked the methodology used to optimize the structure and calculate the NMR chemical shifts in aromatic compounds. The conformational effects of the methoxy group on the (13)C NMR chemical shift then were interpreted by the Natural Bond Orbital (NBO) and Natural Chemical Shift (NCS) approaches, and by excitation analysis of the chemical shifts, breaking down the total nuclear shielding tensor into the contributions from the different occupied orbitals and their magnetic interactions with virtual orbitals. We discovered that the atypical (13)C NMR chemical shifts observed are not directly related to a different conjugation of the lone pair of electrons of the methoxy oxygen with the aromatic ring, as has been suggested. Our analysis indicates that rotation of the methoxy group induces changes in the virtual molecular orbital space, which, in turn, correlate with the predominant part of the contribution of the paramagnetic deshielding connected with the magnetic interactions of the BD(CMet-H)→BD*(CMet-OMet) orbitals, resulting in the experimentally observed deshielding of the (13)C NMR resonance of the out-of-plane methoxy group.

  7. Isoxazole derivatives of alpha-pinene isomers: Synthesis, crystal structure, spectroscopic characterization (FT-IR/NMR/GC-MS) and DFT studies

    NASA Astrophysics Data System (ADS)

    Eryılmaz, Serpil; Gül, Melek; İnkaya, Ersin; Taş, Murat

    2016-03-01

    In this paper, the alpha-pinene isoxazole derivatives (3a-b-c, 4a-b) were synthesized via 1,3-dipolar cycloaddition and characterized with FT-IR, 1H NMR, 13C NMR and GC-MS. Isoxazole (C21H23NO) compound (4a) 6,6,7a,-trimethyl-3-(naphthalen-2-yl)-3a,4,5,6,7,7a-hexahydro-5,7-methanobenzo[d] was characterized by X-ray single crystal diffraction technique. The compound crystallizes in the monoclinic space group P 212121, with Z = 4. The molecular geometry of the compound was optimized by applying Density Functional Theory (DFT/B3LYP) method with 6-31G(d,p) and 6-311 + G(d,p) basis sets in the ground state and geometric parameters were compared with the X-ray analysis results of the structure. Results of the experimental FT-IR and NMR spectral analysis were examined in order to determine the compliance with vibrational frequencies, 1H NMR and 13C NMR chemical shifts values by using the Gauge-Independent Atomic Orbital (GIAO) method calculated over the optimized structure. Besides molecular electrostatic potential (MEP), frontier molecular orbitals (FMOs), some global reactivity descriptors, thermodynamic properties, non-linear optical (NLO) behaviour and Mulliken charge analysis of the (4a) compound were computed with the same method in gas phase, theoretically.

  8. Giant spin-orbit effects on (1)H and (13)C NMR shifts for uranium(vi) complexes revisited: role of the exchange-correlation response kernel, bonding analyses, and new predictions.

    PubMed

    Greif, Anja H; Hrobárik, Peter; Autschbach, Jochen; Kaupp, Martin

    2016-11-09

    Previous relativistic quantum-chemical predictions of unusually large (1)H and (13)C NMR chemical shifts for ligand atoms directly bonded to a diamagnetic uranium(vi) center (P. Hrobárik, V. Hrobáriková, A. H. Greif and M. Kaupp, Angew. Chem., Int. Ed., 2012, 51, 10884) have been revisited by two- and four-component relativistic density functional methods. In particular, the effect of the exchange-correlation response kernel, which had been missing in the previously used two-component version of the Amsterdam Density Functional program, has been examined. Kernel contributions are large for cases with large spin-orbit (SO) contributions to the NMR shifts and may amount to up to ∼30% of the total shifts, which means more than a 50 ppm difference for the metal-bonded carbon shifts in some extreme cases. Previous calculations with a PBE-40HF functional had provided overall reasonable predictions, due to cancellation of errors between the missing kernel contributions and the enhanced exact-exchange (EXX) admixture of 40%. In the presence of an exchange-correlation kernel, functionals with lower EXX admixtures give already good agreement with experiments, and the PBE0 functional provides reasonable predictive quality. Most importantly, the revised approach still predicts unprecedented giant (1)H NMR shifts between +30 ppm and more than +200 ppm for uranium(vi) hydride species. We also predict uranium-bonded (13)C NMR shifts for some synthetically known organometallic U(vi) complexes, for which no corresponding signals have been detected to date. In several cases, the experimental lack of these signals may be attributed to unexpected spectral regions in which some of the (13)C NMR shifts can appear, sometimes beyond the usual measurement area. An extremely large uranium-bonded (13)C shift above 550 ppm, near the upper end of the diamagnetic (13)C shift range, is predicted for a known pincer carbene complex. Bonding analyses allow in particular the magnitude of the SO

  9. 1H NMR investigation of thermally triggered insulin release from poly(N-isopropylacrylamide) microgels.

    PubMed

    Nolan, Christine M; Gelbaum, Leslie T; Lyon, L Andrew

    2006-10-01

    We describe investigations of insulin release from thermoresponsive microgels using variable temperature (1)H NMR. Microgel particles composed of poly(N-isopropylacrylamide) were loaded with the peptide via a swelling technique, and this method was compared to simple equilibrium partitioning. Variable temperature (1)H NMR studies suggest that the swelling loading method results in enhanced entrapment of the peptide versus equilibrium partitioning. A centrifugation-loading assay supports this finding. Pseudo-temperature jump (1)H NMR measurements suggest that the insulin release rate is partially decoupled from microgel collapse. These types of direct release investigations could prove to be useful methods in the future design of controlled macromolecule drug delivery devices.

  10. Hyphenation of capillary HPLC to microcoil (1)H NMR spectroscopy for the determination of tocopherol homologues.

    PubMed

    Krucker, Manfred; Lienau, Annette; Putzbach, Karsten; Grynbaum, Marc David; Schuler, Paul; Albert, Klaus

    2004-05-01

    Highly selective reversed phases (C(30) phases) are self-packed in 250 microm inner diameter fused-silica capillaries and employed for capillary HPLC separation of shape-constrained natural compounds (tocopherol homologues, vitamin E). Miniaturized hyphenated systems such as capillary HPLC-ESI-MS (positive ionization mode) and, with special emphasis, continuous-flow capillary HPLC- NMR are used for structural determination of the separated compounds. Despite the small amount of sample available (1.33 microg of each tocopherol), the authors have been able to monitor the capillary HPLC separation under continuous-flow (1)H NMR conditions, thus allowing an immediate peak identification. Further structural assignment was carried out in the stopped-flow NMR mode as shown, for example, by a 2D (1)H,(1)H COSY NMR spectrum of alpha-tocopherol. We demonstrate in this paper the considerable potential of hyphenated capillary separations coupled to MS and NMR for the investigation of restricted amounts of sample.

  11. 1H and 13C NMR chemical shift assignments of spiro-cycloalkylidenehomo- and methanofullerenes by the DFT-GIAO method.

    PubMed

    Khalilov, L M; Tulyabaev, A R; Yanybin, V M; Tuktarov, A R

    2011-06-01

    The (1)H and (13)C NMR chemical shifts of spiro-cycloalkylidene[60]fullerenes were assigned using experimental NMR data and the Density Functional Theory (DFT)-Gauge Independence Of Atomic Orbitals method (GAIO) calculation method in the Perdew Burke Ernzerhof (PBE)/3z approach. The calculated values of the (13)C NMR chemical shifts adequately reproduce the experimental values at this quantum chemistry approach. Similar assignments will be helpful for (13)C NMR spectral analysis of homo- and methano[60]fullerene derivatives for structure elucidation and to determine the influence of fullerene frames on substituents and the influence of substituents on fullerene cores.

  12. Alternative determination of blood alcohol concentration by (1)H NMR spectroscopy.

    PubMed

    Zailer, Elina; Diehl, Bernd W K

    2016-02-05

    A rapid, accurate and specific proton nuclear magnetic resonance ((1)H NMR) spectroscopic method is developed to determine ethanol in blood, known as the blood alcohol concentration (BAC). The limits of detection and quantification are 0.02g/L and 0.07g/L, respectively. The (1)H NMR spectra show linearity for whole blood and serum samples of a concentration range of 0.00-3.00g/L (R(2)>0.9995). The (1)H NMR method is applied and validated for whole blood as the sample media. Real driving under influence case samples are analyzed with the reference enzyme-based alcohol dehydrogenase and headspace gas chromatography techniques by the Forensic Medicine in Bonn. The reference results are compared with the (1)H NMR spectroscopic results. The validation and comparison indicate that (1)H NMR is suitable for the quantification of BAC in whole blood. This technique has the advantages of automated analysis with good measurement precision and fast sample throughput. A drop of blood (V=20μL) is adequate for an analysis leading to a possible simplification of the sample collection. Due to the non-destructive method, follow-up examinations by (1)H NMR spectroscopy or DNA determinations by different techniques (PCR, in situ hybridization) are possible in resolving legal disputes.

  13. 1H NMR characterization of a hen ovalbumin tyrosinamide N-linked oligosaccharide library.

    PubMed

    Corradi Da Silva, M L; Stubbs, H J; Tamura, T; Rice, K G

    1995-04-20

    A library of 15 N-linked oligosaccharide structures was prepared from ovalbumin and characterized using high-field NMR and mass spectrometry. The oligosaccharides were enzymatically released from ovalbumin glycopeptides, and the reducing ends were reacted with ammonium bicarbonate to form oligosaccharide-glycosylamines. These reacted with Boc-tyrosine-N-hydroxysuccinimide ester, resulting in a mixture of tyrosinamide-oligosaccharides. The Boc group was removed to expose an amine terminus which enhanced the resolution of tyrosinamide-oligosaccharides when chromatographed on reverse-phase HPLC. Ten major and five minor oligosaccharides were purified on a micromole scale and characterized using 1H NMR and FAB-MS. The structures include high-mannose, hybrid, and complex oligosaccharides possessing from two to five antenna, providing the most complete definition of ovalbumin N-linked oligosaccharides to date. The resulting library is well suited to biological studies due to the presence of a single terminal tyrosine residue on each oligosaccharide that allows radioiodination or the attachment of additional probes to these glycoconjugates prior to biological studies.

  14. Identification and quantitative determination of carbohydrates in ethanolic extracts of two conifers using 13C NMR spectroscopy.

    PubMed

    Duquesnoy, Emilie; Castola, Vincent; Casanova, Joseph

    2008-04-07

    We developed a method for the direct identification and quantification of carbohydrates in raw vegetable extracts using (13)C NMR spectroscopy without any preliminary step of precipitation or reduction of the components. This method has been validated (accuracy, precision and response linearity) using pure compounds and artificial mixtures before being applied to authentic ethanolic extracts of pine needles, pine wood and pine cones and fir twigs. We determined that carbohydrates represented from 15% to 35% of the crude extracts in which pinitol was the principal constituent accompanied by arabinitol, mannitol, glucose and fructose.

  15. Triterpenes in the hexane extract of leaves of Olea europaea L.: analysis using 13C-NMR spectroscopy.

    PubMed

    Duquesnoy, Emilie; Castola, Vincent; Casanova, Joseph

    2007-01-01

    Two neutral triterpenes and a triterpene acid were identified and quantified directly, in the absence of any purification steps, in a precipitate obtained during the industrial extraction of the leaves of Olea europaea L. using 13C-NMR spectroscopy (spectrometer operating at 4.7 T equipped with a 10 mm probe). The method was optimised in order to reduce the duration of analysis with a routine NMR spectrometer. Together with long-chain linear compounds, erythrodiol, uvaol and oleanolic acid accounted for 27.3, 18.3 and 12.5% of the precipitate, respectively.

  16. Use of solid-state 13C NMR in structural studies of humic acids and humin from Holocene sediments

    USGS Publications Warehouse

    Hatcher, P.G.; VanderHart, D.L.; Earl, W.L.

    1980-01-01

    13C NMR spectra of solid humic substances in Holocene sediments have been obtained using cross polarization with magic-angle sample spinning techniques. The results demonstrate that this technique holds great promise for structural characterizations of complex macromolecular substances such as humin and humic acids. Quantifiable distinctions can be made between structural features of aquatic and terrestrial humic substances. The aliphatic carbons of the humic substances are dominant components suggestive of input from lipid-like materials. An interesting resemblance is also noted between terrestrial humic acid and humin spectra. ?? 1980.

  17. (1)H, (13)C NMR and X-ray crystallographic studies of highly polyhalogenated derivatives of costunolide lactone.

    PubMed

    Corona, D; Díaz, E; Nava, J L; Guzmán, A; Barrios, H; Fuentes, A; Hernandez-Plata, S A; Allard, J; Jankowski, C K

    2005-11-01

    The costunolide lactone, a sesquiterpene compound isolated from Zaluzania triiloba species, reacted with several dihalocarbene sources produced by trihaloform-NaOH under successive phase transfer reactions yielding mono-, bis- and tris-dihalocyclopropane adducts. The structures, as well as the configurational assignments of the different derivatives, were established by (1)H and (13)C NMR spectroscopy and assisted by X-ray crystallographic and molecular modelling studies. The specific shielding of protons in the neighbourhood of different halogens on the cyclopropane moieties was correlated to the pseudocontact interactions.

  18. Investigations on computed 13C NMR one-dimensional non-refocused INEPT experiments for structural determinations in O-methylated glycosides

    NASA Astrophysics Data System (ADS)

    Pouységu, Laurent; Nobert, Philippe; Deffieux, Denis; De Jéso, Bernard; Lartigue, Jean-Claude; Pétraud, Michel; Ratier, Max

    1999-10-01

    A new one-dimensional 13C NMR approach for the determination of methoxyl substituents configuration in O-methylated glycosides is presented. Assignments are based on structural investigations by non-refocused INEPT experiments associated with numerical methods.

  19. 13C- and 1H-NMR studies of oxyanion and tetrahedral intermediate stabilization by the serine proteinases: optimizing inhibitor warhead specificity and potency by studying the inhibition of the serine proteinases by peptide-derived chloromethane and glyoxal inhibitors.

    PubMed

    Malthouse, J P G

    2007-06-01

    Catalysis by the serine proteinases proceeds via a tetrahedral intermediate whose oxyanion is stabilized by hydrogen-bonding in the oxyanion hole. There have been extensive (13)C-NMR studies of oxyanion and tetrahedral intermediate stabilization in trypsin, subtilisin and chymotrypsin using substrate-derived chloromethane inhibitors. One of the limitations of these inhibitors is that they irreversibly alkylate the active-site histidine residue which results in the oxyanion not being in the optimal position in the oxyanion hole. Substrate-derived glyoxal inhibitors are reversible inhibitors which, if they form tetrahedral adducts in the same way as substrates form tetrahedral intermediates, will overcome this limitation. Therefore we have synthesized (13)C-enriched substrate-derived glyoxal inhibitors which have allowed us to use (13)C-NMR and (1)H-NMR to determine how they interact with proteinases. It is hoped that these studies will help in the design of specific and highly potent warheads for serine proteinase inhibitors.

  20. Experimental and theoretical study of substituent effect on 13C NMR chemical shifts of 5-arylidene-2,4-thiazolidinediones

    NASA Astrophysics Data System (ADS)

    Rančić, Milica P.; Trišović, Nemanja P.; Milčić, Miloš K.; Ajaj, Ismail A.; Marinković, Aleksandar D.

    2013-10-01

    The electronic structure of 5-arylidene-2,4-thiazolidinediones has been studied by using experimental and theoretical methodology. The theoretical calculations of the investigated 5-arylidene-2,4-thiazolidinediones have been performed by the use of quantum chemical methods. The calculated 13C NMR chemical shifts and NBO atomic charges provide an insight into the influence of such a structure on the transmission of electronic substituent effects. Linear free energy relationships (LFERs) have been further applied to their 13C NMR chemical shifts. The correlation analyses for the substituent-induced chemical shifts (SCS) have been performed with σ using SSP (single substituent parameter), field (σF) and resonance (σR) parameters using DSP (dual substituent parameter), as well as the Yukawa-Tsuno model. The presented correlations account satisfactorily for the polar and resonance substituent effects operative at Cβ, and C7 carbons, while reverse substituent effect was found for Cα. The comparison of correlation results for the investigated molecules with those obtained for seven structurally related styrene series has indicated that specific cross-interaction of phenyl substituent and groups attached at Cβ carbon causes increased sensitivity of SCS Cβ to the resonance effect with increasing of electron-accepting capabilities of the group present at Cβ.

  1. Evolution of organic matter during composting of different organic wastes assessed by CPMAS {sup 13}C NMR spectroscopy

    SciTech Connect

    Caricasole, P.; Provenzano, M.R.; Senesi, N.

    2011-03-15

    In this paper, the evolution of organic matter (OM) during composting of different mixtures of various organic wastes was assessed by means of chemical analyses and CPMAS {sup 13}C NMR spectroscopy measured during composting. The trends of temperatures and C/N ratios supported the correct evolution of the processes. The CPMAS {sup 13}C NMR spectra of all composting substrates indicated a reduction in carbohydrates and an increase in aromatic, phenolic, carboxylic and carbonylic C which suggested a preference by microorganisms for easily degradable C molecules. The presence of hardly degradable pine needles in one of the substrates accounted for the lowest increase in alkyl C and the lowest reduction in carbohydrates and carboxyl C as opposite to another substrate characterized by the presence of a highly degradable material such as spent yeast from beer production, which showed the highest increase of the alkyl C/O-alkyl C ratio. The highest increase of COOH deriving by the oxidative degradation of cellulose was shown by a substrate composed by about 50% of plant residues. The smallest increases in alkyl C/O-alkyl C ratio and in polysaccharides were associated to the degradation of proteins and lipids which are major components of sewage sludge. Results obtained were related to the different composition of fresh organic substrates and provided evidence of different OM evolution patterns as a function of the initial substrate composition.

  2. The retrogradation properties of glutinous rice and buckwheat starches as observed with FT-IR, 13C NMR and DSC.

    PubMed

    Lian, Xijun; Wang, Changjun; Zhang, Kunsheng; Li, Lin

    2014-03-01

    The experiment was conducted to study the retrogradation properties of glutinous rice and buckwheat starch with wavelengths of maximum absorbance, FT-IR, (13)C NMR, and DSC. The results show that the starches in retrograded glutinous rice starch and glutinous rice amylopectin could not form double helix. The IR results show that protein inhabits in glutinous rice and maize starches in a different way and appearance of C-H symmetric stretching vibration at 2852 cm(-1) in starch might be appearance of protein. Retrogradation untied the protein in glutinous amylopectin. Enthalpies of sweet potato and maize granules are higher than those of their retrograded starches. The (13)C NMR results show that retrogradation of those two starches leads to presence of β-anomers and retrogradation might decompose lipids in glutinous rice amylopectin into small molecules. Glutinous rice starch was more inclined to retrogradation than buckwheat starch. The DSC results show that the second peak temperatures for retrograded glutinous rice and buckwheat starches should be assigned to protein. The SEM results show that an obvious layer structure exists in retrograded glutinous rice amylopectin.

  3. Evolution of organic matter during composting of different organic wastes assessed by CPMAS 13C NMR spectroscopy.

    PubMed

    Caricasole, P; Provenzano, M R; Hatcher, P G; Senesi, N

    2011-03-01

    In this paper, the evolution of organic matter (OM) during composting of different mixtures of various organic wastes was assessed by means of chemical analyses and CPMAS (13)C NMR spectroscopy measured during composting. The trends of temperatures and C/N ratios supported the correct evolution of the processes. The CPMAS (13)C NMR spectra of all composting substrates indicated a reduction in carbohydrates and an increase in aromatic, phenolic, carboxylic and carbonylic C which suggested a preference by microorganisms for easily degradable C molecules. The presence of hardly degradable pine needles in one of the substrates accounted for the lowest increase in alkyl C and the lowest reduction in carbohydrates and carboxyl C as opposite to another substrate characterized by the presence of a highly degradable material such as spent yeast from beer production, which showed the highest increase of the alkyl C/O-alkyl C ratio. The highest increase of COOH deriving by the oxidative degradation of cellulose was shown by a substrate composed by about 50% of plant residues. The smallest increases in alkyl C/O-alkyl C ratio and in polysaccharides were associated to the degradation of proteins and lipids which are major components of sewage sludge. Results obtained were related to the different composition of fresh organic substrates and provided evidence of different OM evolution patterns as a function of the initial substrate composition.

  4. Random isotopolog libraries for protein perturbation studies. 13C NMR studies on lumazine protein of Photobacterium leiognathi.

    PubMed

    Illarionov, Boris; Lee, Chan Yong; Bacher, Adelbert; Fischer, Markus; Eisenreich, Wolfgang

    2005-11-25

    [graph: see text] Lumazine proteins of luminescent bacteria are paralogs of riboflavin synthase which are devoid of catalytic activity but bind the riboflavin synthase substrate, 6,7-dimethyl-8-ribityllumazine, with high affinity and are believed to serve as optical transponders for bioluminescence emission. Lumazine protein of Photobacterium leiognathi was expressed in a recombinant Escherichia coli host and was reconstituted with mixtures (random libraries) of 13C-labeled isotopologs of 6,7-dimethyl-8-ribityllumazine or riboflavin that had been prepared by biotransformation of [U-(13)C6]-, [1-(13)C1]-, [2-(13)C1]-, and [3-(13)C1]glucose. 13C NMR analysis of the protein/ligand complexes afforded the assignments of the 13C NMR chemical shifts for all carbon atoms of the protein-bound ligands by isotopolog abundance editing. The carbon atoms of the ribityl groups of both ligands studied were shifted up to 6 ppm upon binding to the protein. Chemical shift modulation of the side chain and chromophore carbon atoms due to protein/ligand interaction is discussed on the basis of the sequence similarity between lumazine protein and riboflavin synthase.

  5. Variability of cork from Portuguese Quercus suber studied by solid-state (13)C-NMR and FTIR spectroscopies.

    PubMed

    Lopes, M H; Barros, A S; Pascoal Neto, C; Rutledge, D; Delgadillo, I; Gil, A M

    2001-01-01

    A new approach is presented for the study of the variability of Portuguese reproduction cork using solid-state (13)C-NMR spectroscopy and photoacoustic (PAS) FTIR (FTIR-PAS) spectroscopy combined with chemometrics. Cork samples were collected from 12 different geographical sites, and their (13)C-cross-polarization with magic angle spinning (CP/MAS) and FTIR spectra were registered. A large spectral variability among the cork samples was detected by principal component analysis and found to relate to the suberin and carbohydrate contents. This variability was independent of the sample geographical origin but significantly dependent on the cork quality, thus enabling the distinction of cork samples according to the latter property. The suberin content of the cork samples was predicted using multivariate regression models based on the (13)C-NMR and FTIR spectra of the samples as reported previously. Finally, the relationship between the variability of the (13)C-CP/MAS spectra with that of the FTIR-PAS spectra was studied by outer product analysis. This type of multivariate analysis enabled a clear correlation to be established between the peaks assigned to suberin and carbohydrate in the FTIR spectrum and those appearing in the (13)C-CP/MAS spectra.

  6. 1H, 13C NMR and DFT Study of Hydrogen Bonding in Imidazolium-based Ionic Liquids.

    PubMed

    Balevičius, Vytautas; Gdaniec, Zofia; Džiaugys, Lukas; Kuliešius, Feliksas; Maršalka, Arūnas

    2011-09-01

    The ionic liquid 1-decyl-3-methyl-imidazolium bromide [C10mim][Br], the neat material, and also dissolved (~0.01 mole fraction) in various dielectric media (acetonitrile, benzene, chloroform, dichloromethane, methanol, 2-butanol and H2O) was studied using 1H and 13C NMR spectroscopy. The most important interaction in this compound is considered to be the Br-...H-C2+ hydrogen bond, which is formed between the anions and cations. The obtained results show that dielectric medium influence mostly the behavior of the Br-...H-C2+ bridge proton. The changes observed in 1H and 13C NMR spectra of [C10mim][Br] with increasing solvents polarity and temperature can be explained applying the model of the lengthening of the H2...Br- bond with the accompanying thickening of the solvation shell of bromine anion and C2-H bond contraction. The short-range order effects related to the configuration of neighboring dipoles of solvent molecules are more important for the solvation ability of small anions than the bulk solvent field effect. However, the solvents, molecules of which tend to associate via hydrogen bonding, can significantly affect the dynamics of anions.

  7. Hyperpolarized 13C NMR lifetimes in the liquid-state: relating structures and T1 relaxation times

    NASA Astrophysics Data System (ADS)

    Parish, Christopher; Niedbalski, Peter; Hashami, Zohreh; Fidelino, Leila; Kovacs, Zoltan; Lumata, Lloyd

    Among the various attempts to solve the insensitivity problem in nuclear magnetic resonance (NMR), the physics-based technique dissolution dynamic nuclear polarization (DNP) is probably the most successful method of hyperpolarization or amplifying NMR signals. Using this technique, liquid-state NMR signal enhancements of several thousand-fold are expected for low-gamma nuclei such as carbon-13. The lifetimes of these hyperpolarized 13C NMR signals are directly related to their 13C spin-lattice relaxation times T1. Depending upon the 13C isotopic location, the lifetimes of hyperpolarized 13C compounds can range from a few seconds to minutes. In this study, we have investigated the hyperpolarized 13C NMR lifetimes of several 13C compounds with various chemical structures from glucose, acetate, citric acid, naphthalene to tetramethylallene and their deuterated analogs at 9.4 T and 25 deg C. Our results show that the 13C T1s of these compounds can range from a few seconds to more than 60 s at this field. Correlations between the chemical structures and T1 relaxation times will be discussed and corresponding implications of these results on 13C DNP experiments will be revealed. US Dept of Defense Award No. W81XWH-14-1-0048 and Robert A. Welch Foundation Grant No. AT-1877.

  8. Quantitative Determination of Carthamin in Carthamus Red by 1H-NMR Spectroscopy.

    PubMed

    Yoshida, Takamitsu; Terasaka, Kazuyoshi; Kato, Setsuko; Bai, Fan; Sugimoto, Naoki; Akiyama, Hiroshi; Yamazaki, Takeshi; Mizukami, Hajime

    2013-01-01

    Carthamus Red is a food colorant prepared from the petals of Carthamus tinctorius (Asteraceae) whose major pigment is carthamin. Since an authentic carthamin standard is difficult to obtain commercially for the preparation of calibration curves in HPLC assays, we applied (1)H-NMR spectroscopy to the quantitative determination of carthamin in commercial preparations of Carthamus Red. Carthamus Red was repeatedly extracted in methanol and the extract was dissolved in pyridine-d(5) containing hexamethyldisilane (HMD) prior to (1)H-NMR spectroscopic analysis. The carthamin contents were calculated from the ratios of singlet signal intensities at approximately σ: 9.3 derived from H-16 of carthamin to those of the HMD signal at σ: 0. The integral ratios exhibited good repeatability among NMR spectroscopic analyses. Both the intra-day and inter-day assay variations had coefficients of variation of <5%. Based on the coefficient of absorption, the carthamin contents of commercial preparations determined by (1)H-NMR spectroscopy correlated well with those determined by colorimetry, although the latter were always approximately 1.3-fold higher than the former, irrespective of the Carthamus Red preparations. In conclusion, the quantitative (1)H-NMR spectroscopy used in the present study is simple and rapid, requiring no carthamin standard for calibration. After HMD concentration has been corrected using certified reference materials, the carthamin contents determined by (1)H-NMR spectroscopy are System of Units (SI)-traceable.

  9. In vivo1H NMR spectroscopy of the human brain at 9.4 T: Initial results

    NASA Astrophysics Data System (ADS)

    Deelchand, Dinesh Kumar; Moortele, Pierre-François Van de; Adriany, Gregor; Iltis, Isabelle; Andersen, Peter; Strupp, John P.; Thomas Vaughan, J.; Uğurbil, Kâmil; Henry, Pierre-Gilles

    2010-09-01

    In vivo proton NMR spectroscopy allows non-invasive detection and quantification of a wide range of biochemical compounds in the brain. Higher field strength is generally considered advantageous for spectroscopy due to increased signal-to-noise and increased spectral dispersion. So far 1H NMR spectra have been reported in the human brain up to 7 T. In this study we show that excellent quality short echo time STEAM and LASER 1H NMR spectra can be measured in the human brain at 9.4 T. The information content of the human brain spectra appears very similar to that measured in the past decade in rodent brains at the same field strength, in spite of broader linewidth in human brain. Compared to lower fields, the T1 relaxation times of metabolites were slightly longer while T2 relaxation values of metabolites were shorter (<100 ms) at 9.4 T. The linewidth of the total creatine (tCr) resonance at 3.03 ppm increased linearly with magnetic field (1.35 Hz/T from 1.5 T to 9.4 T), with a minimum achievable tCr linewidth of around 12.5 Hz at 9.4 T. At very high field, B0 microsusceptibility effects are the main contributor to the minimum achievable linewidth.

  10. Hydrocarbon type analysis of jet fuels by /sup 1/H and /sup 13/C NMR

    SciTech Connect

    Netzel, D.A.; Hunter, P.M.

    1981-05-01

    This report describes the application of NMR spectroscopy to the chemical characterization without prior chromatographic separation of jet fuels and various fuel blends containing varying amounts of paraffinic and aromatic constituents. Equations are derived by which the total percent paraffins and aromatics as well as percent monoaromatics and diaromatics can be calculated. Computer programs for the various calculations are included. The results obtained by NMR are compared to those obtained by MS.

  11. Quantification of taxanes in a leaf and twig extract from Taxus baccata L. using 13C NMR spectroscopy.

    PubMed

    Paoli, Mathieu; Bighelli, Ange; Castola, Vincent; Tomi, Félix; Casanova, Joseph

    2013-11-01

    In the course of our ongoing work on the chemical characterization of Taxus baccata L. growing wild in Corsica, we have developed and validated a method for direct quantification of taxane derivatives by (13)C NMR using 10-deacetylbaccatin III as reference compound and 1,6-hexanediol as internal standard. We have observed good accuracy (relative errors between 0.3% and 3.5%), linearity (R(2) = 0.999) and precision (reproducibility 8.5 mg ± 1.1%) of the measurements. The experimental procedure was applied to the quantification of six identified taxanes in a fraction of chromatography of a methanol extract of T. baccata leaves. This method can be applied to other compounds bearing the taxane skeleton.

  12. Enantiomeric differentiation of oxygenated p-menthane derivatives by 13C NMR using Yb(hfc)3.

    PubMed

    Lanfranchi, Don Antoine; Blanc, Marie-Cécile; Vellutini, Muriel; Bradesi, Pascale; Casanova, Joseph; Tomi, Félix

    2008-12-01

    The (13)C NMR behaviour of 21 p-menthanic terpene bearing an oxygenated function (alcohol, ketone, acetate) was examined in the presence of a chiral lanthanide shift reagent (Yb(hfc)(3)). For each monocyclic compound, we measured the lanthanide-induced shift (LIS) on the signals of the carbons and the splitting of signals allowing the enantiomeric differentiation. Some general features were found about their LIS behaviour: experimental data establishing distinct patterns for carvomenthone-like compounds and menthone-like compounds. The enantiomeric splitting was observed for the majority of signals in the spectrum of each compound. In the case of alcohols and acetates, the influence of the relative stereochemistry (cis vs trans) of isopropyl(ene) and the binding function was discussed.

  13. Brominated Compounds from Marine Sponges of the Genus Aplysina and a Compilation of Their 13C NMR Spectral Data

    PubMed Central

    Lira, Narlize Silva; Montes, Ricardo Carneiro; Tavares, Josean Fechine; da Silva, Marcelo Sobral; da Cunha, Emidio V. L.; de Athayde-Filho, Petronio Filgueiras; Rodrigues, Luis Cezar; da Silva Dias, Celidarque; Barbosa-Filho, Jose Maria

    2011-01-01

    Aplysina is the best representative genus of the family Aplysinidae. Halogenated substances are its main class of metabolites. These substances contribute greatly to the chemotaxonomy and characterization of the sponges belonging to this genus. Due to their pharmacological activities, these alkaloids are of special interest. The chemistry of halogenated substances and of the alkaloids has long been extensively studied in terrestrial organisms, while the number of marine organisms studied has just started to increase in the last decades. This review describes 101 halogenated substances from 14 species of Aplysina from different parts of the world. These substances can be divided into the following classes: bromotyramines (A), cavernicolins (B), hydroverongiaquinols (C), bromotyrosineketals (D), bromotyrosine lactone derivatives (E), oxazolidones (F), spiroisoxazolines (G), verongiabenzenoids (H), verongiaquinols (I), and dibromocyclohexadienes (J). A compilation of their 13C NMR data is also part of the review. For this purpose 138 references were consulted. PMID:22163189

  14. Conditions for 13C NMR Detection of 2-Hydroxyglutarate in Tissue Extracts from IDH-Mutated Gliomas

    PubMed Central

    Pichumani, Kumar; Mashimo, Tomoyuki; Baek, Hyeon-Man; Ratnakar, James; Mickey, Bruce; DeBerardinis, Ralph J.; Maher, Elizabeth A.; Bachoo, Robert M.; Malloy, Craig R.; Kovacs, Zoltan

    2015-01-01

    13C NMR spectroscopy of extracts from patient tumor samples provides rich information about metabolism. However, in IDH-mutant gliomas 13C labeling is obscured in glutamate and glutamine by the oncometabolite, 2-hydroxyglutaric acid (2HG), prompting development of a simple method to resolve the metabolites. J-coupled multiplets in 2HG were similar to glutamate and glutamine and could be clearly resolved at pH 6. A cryogenically-cooled 13C probe but not J-resolved heteronuclear single quantum coherence spectroscopy significantly improved detection of 2HG. These methods enable the monitoring of 13C-13C spin-spin couplings in 2HG expressing IDH mutant gliomas. PMID:25908561

  15. Local structure and molecular motions in imidazolium hydrogen malonate crystal as studied by 2H and 13C NMR

    NASA Astrophysics Data System (ADS)

    Mizuno, M.; Chizuwa, M.; Umiyama, T.; Kumagai, Y.; Miyatou, T.; Ohashi, R.; Ida, T.; Tansho, M.; Shimizu, T.

    2015-04-01

    The local structure and molecular motion of the imidazolium hydrogen malonate crystal were investigated using solid-state 2H and 13C NMR. The imidazolium ion undergoes isotropic rotation, which is correlated with a defect in the crystal, as observed by 2H NMR broadline spectra above 263 K. A 180∘ flip of the imidazolium ion in the regular site was observed from 2H NMR quadrupole Carr-Purcell-Meiboom-Gill (QCPMG) spectra. The Grotthuss mechanism was accompanied by a 180∘ flip of the imidazolium ion in regular sites. Moreover, the proton transfer associated with the imidazolium ion of the defective crystal is important for proton conductivity of the imidazolium hydrogen malonate crystal.

  16. Beta-alanine-hydrochloride (2:1) crystal: structure, 13C NMR and vibrational properties, protonation character.

    PubMed

    Godzisz, D; Ilczyszyn, M; Ciunik, Z

    2003-01-15

    The crystal structure of beta-alanine-hydrochloride (2:1) complex (2A-HCl) has been determined by X-ray diffraction method at 298 and 100 K as monoclinic, space group C2/c, Z=4. The crystal comprises chloride anions and protonated beta-alanine dimers: two beta-alanine zwitterions are joined by strong, symmetric (Ci) hydrogen bond with the O...O distance of 2.473 A at room temperature. Powder FT-IR and FT-Raman as well as solid state 13C NMR spectra provide insights into the solid structure of this complex, character of its hydrogen bonds and the beta-alanine protonation.

  17. Beta-alanine-oxalic acid (1:1) hemihydrate crystal: structure, 13C NMR and vibrational properties, protonation character.

    PubMed

    Godzisz, D; Ilczyszyn, M; Ilczyszyn, M M

    2003-03-01

    The crystal structure of beta-alanine-oxalic acid (1:1) hemihydrate complex has been reinvestigated by X-ray diffraction method at 293 K. Formation of monoclinic crystal system belonging to C2/c space group and consisting of semi-oxalate chains, diprotonated beta-alanine dimers and water molecules bonded to both these units is confirmed. New results are obtained for distances in the carboxylic groups and hydrogen bonds. These structural observations are used for protonation degree monitoring on the carboxylic oxygen atoms. They are in accordance with our vibrational study. The 13C NMR spectra provide insights into the solid structure of this complex, character of its hydrogen bonds and the beta-alanine protonation.

  18. Bonded Cumomer Analysis of Human Melanoma Metabolism Monitored by 13C NMR Spectroscopy of Perfused Tumor Cells*

    PubMed Central

    Shestov, Alexander A.; Mancuso, Anthony; Lee, Seung-Cheol; Guo, Lili; Nelson, David S.; Roman, Jeffrey C.; Henry, Pierre-Gilles; Leeper, Dennis B.; Blair, Ian A.; Glickson, Jerry D.

    2016-01-01

    A network model for the determination of tumor metabolic fluxes from 13C NMR kinetic isotopomer data has been developed and validated with perfused human DB-1 melanoma cells carrying the BRAF V600E mutation, which promotes oxidative metabolism. The model generated in the bonded cumomer formalism describes key pathways of tumor intermediary metabolism and yields dynamic curves for positional isotopic enrichment and spin-spin multiplets. Cells attached to microcarrier beads were perfused with 26 mm [1,6-13C2]glucose under normoxic conditions at 37 °C and monitored by 13C NMR spectroscopy. Excellent agreement between model-predicted and experimentally measured values of the rates of oxygen and glucose consumption, lactate production, and glutamate pool size validated the model. ATP production by glycolytic and oxidative metabolism were compared under hyperglycemic normoxic conditions; 51% of the energy came from oxidative phosphorylation and 49% came from glycolysis. Even though the rate of glutamine uptake was ∼50% of the tricarboxylic acid cycle flux, the rate of ATP production from glutamine was essentially zero (no glutaminolysis). De novo fatty acid production was ∼6% of the tricarboxylic acid cycle flux. The oxidative pentose phosphate pathway flux was 3.6% of glycolysis, and three non-oxidative pentose phosphate pathway exchange fluxes were calculated. Mass spectrometry was then used to compare fluxes through various pathways under hyperglycemic (26 mm) and euglycemic (5 mm) conditions. Under euglycemic conditions glutamine uptake doubled, but ATP production from glutamine did not significantly change. A new parameter measuring the Warburg effect (the ratio of lactate production flux to pyruvate influx through the mitochondrial pyruvate carrier) was calculated to be 21, close to upper limit of oxidative metabolism. PMID:26703469

  19. (1)H and (13)C NMR chemical shifts of methacrylate molecules associated with DMPC and/or DPPC liposomes.

    PubMed

    Fujisawa, Seiichiro; Ishihara, Mariko; Kadoma, Yoshinori

    2005-01-01

    In the light of recent developments, changes in (1)H and (13)C NMR chemical shifts of methacrylate molecule associated with DMPC (L-alpha dimyristoylphosphatidylcholine) or DPPC (L-alpha-dipalmitoylphosphatidylcholine) liposomes as a model for mimic native lipid bilayers were studied at 30, 37, and 52 degrees C. The chemical shifts of 3Ha, 3C, and 4C resonances in methacrylates (see Fig. 2) were greatly shifted higher field, suggesting the methacrylate molecule-lipid bilayer interaction. Comparison of the findings with methyl methacrylate (MMA), ethylene dimethacrylate (EDMA), and triethyleneglycol dimethacrylate (TEGDMA) revealed that the interaction of dimethacrylates (EDMA, TEGDMA) was greater than monomethacrylate, MMA. Their interaction with DMPC liposomes was also judged by a differential scanning calorimetry (DSC), indicating that the interaction was characterized by decreasing the enthalpy, entropy, and transition co-operativity. The evidence of the upfield NMR-shifts for methacrylate molecules was also judged by the descriptors such as the reactivity (HOMO-LUMO energy) and the electrostatic function (partial charges) between methacrylate molecules and DPPC, calculated by a PM 3 semiempirical MO method. The upfield NMR shifts were considerably well interpreted from the descriptors. NMR screening technique in methacrylates to phospholipid targets would be highly valuable in biomaterial developments. Figure 2 Changes in (1)H and (13)C NMR chemical shifts of methacrylate molecule associated with DMPC or DPPC liposomes. DMPC liposomes/MMA (1:1, molar ratio) and DMPC/TEGDMA (1:1) liposomes were measured at 30 degrees C. In DPPC liposome system, the rippled gel phase was measured at 30 degrees C, whereas the liquid crystalline phase for MMA and for both EDMA and TEGDMA were measured at 52 degrees C and 37 degrees C, respectively.

  20. Molecular Structures from [superscript 1]H NMR Spectra: Education Aided by Internet Programs

    ERIC Educational Resources Information Center

    Debska, Barbara; Guzowska-Swider, Barbara

    2007-01-01

    The article presents the way in which freeware Internet programs can be applied to teach [superscript 1]H NMR spectroscopy. The computer programs described in this article are part of the educational curriculum that explores spectroscopy and spectra interpretation. (Contains 6 figures.)

  1. Temperature imaging by 1H NMR and suppression of convection in NMR probes

    PubMed

    Hedin; Furo

    1998-03-01

    A simple arrangement for suppressing convection in NMR probes is tested experimentally. Diffusion experiments are used to determine the onset of convection and 1H temperature imaging helps to rationalize the somewhat surprising results. A convenient new 1H NMR thermometer, CH2Br2 dissolved in a nematic thermotropic liquid crystal, is presented. Copyright 1998 Academic Press.

  2. Complete Assignment of (1)H-NMR Resonances of the King Cobra Neurotoxin CM-11.

    PubMed

    Pang, Yu-Xi; Liu, Wei-Dong; Liu, Ai-Zhuo; Pei, Feng-Kui

    1997-01-01

    The king cobra (Ophiophagus Hannah) neurotoxin CM-Il is long-chain peptide with 72 amino acid residues. Its complete assignment of (1)H-NMR resonances was obtained using various 2D-NMR technologies, including DQF-COSY, clean-TOCSY and NOESY.

  3. Synthesis of stereospecifically deuterated desoxypodophyllotoxins and 1H-nmr assignment of desoxypodophyllotoxin

    NASA Technical Reports Server (NTRS)

    Pullockaran, A. J.; Kingston, D. G.; Lewis, N. G.

    1989-01-01

    [4 beta- 2H1]Desoxypodophyllotoxin [3], [4 alpha- 2H1]desoxypodophyllotoxin [4], and [4, 4- 2 H2]desoxypodophyllotoxin [9] were prepared from podophyllotoxin [1] via its chloride [5]. A complete assignment of the 1H-nmr spectrum of desoxypodophyllotoxin [2] was made on the basis of the spectra of the deuterated compounds [3] and [4].

  4. Distinguishing Benign from Malignant Pancreatic and Periampullary Lesions Using Combined Use of 1H-NMR Spectroscopy and Gas Chromatography–Mass Spectrometry

    PubMed Central

    McConnell, Yarrow J.; Farshidfar, Farshad; Weljie, Aalim M.; Kopciuk, Karen A.; Dixon, Elijah; Ball, Chad G.; Sutherland, Francis R.; Vogel, Hans J.; Bathe, Oliver F.

    2017-01-01

    Previous work demonstrated that serum metabolomics can distinguish pancreatic cancer from benign disease. However, in the clinic, non-pancreatic periampullary cancers are difficult to distinguish from pancreatic cancer. Therefore, to test the clinical utility of this technology, we determined whether any pancreatic and periampullary adenocarcinoma could be distinguished from benign masses and biliary strictures. Sera from 157 patients with malignant and benign pancreatic and periampullary lesions were analyzed using proton nuclear magnetic resonance (1H-NMR) spectroscopy and gas chromatography–mass spectrometry (GC-MS). Multivariate projection modeling using SIMCA-P+ software in training datasets (n = 80) was used to generate the best models to differentiate disease states. Models were validated in test datasets (n = 77). The final 1H-NMR spectroscopy and GC-MS metabolomic profiles consisted of 14 and 18 compounds, with AUROC values of 0.74 (SE 0.06) and 0.62 (SE 0.08), respectively. The combination of 1H-NMR spectroscopy and GC-MS metabolites did not substantially improve this performance (AUROC 0.66, SE 0.08). In patients with adenocarcinoma, glutamate levels were consistently higher, while glutamine and alanine levels were consistently lower. Pancreatic and periampullary adenocarcinomas can be distinguished from benign lesions. To further enhance the discriminatory power of metabolomics in this setting, it will be important to identify the metabolomic changes that characterize each of the subclasses of this heterogeneous group of cancers. PMID:28098776

  5. Quantification of Human Brain Metabolites from in Vivo1H NMR Magnitude Spectra Using Automated Artificial Neural Network Analysis

    NASA Astrophysics Data System (ADS)

    Hiltunen, Yrjö; Kaartinen, Jouni; Pulkkinen, Juhani; Häkkinen, Anna-Maija; Lundbom, Nina; Kauppinen, Risto A.

    2002-01-01

    Long echo time (TE=270 ms) in vivo proton NMR spectra resembling human brain metabolite patterns were simulated for lineshape fitting (LF) and quantitative artificial neural network (ANN) analyses. A set of experimental in vivo1H NMR spectra were first analyzed by the LF method to match the signal-to-noise ratios and linewidths of simulated spectra to those in the experimental data. The performance of constructed ANNs was compared for the peak area determinations of choline-containing compounds (Cho), total creatine (Cr), and N-acetyl aspartate (NAA) signals using both manually phase-corrected and magnitude spectra as inputs. The peak area data from ANN and LF analyses for simulated spectra yielded high correlation coefficients demonstrating that the peak areas quantified with ANN gave similar results as LF analysis. Thus, a fully automated ANN method based on magnitude spectra has demonstrated potential for quantification of in vivo metabolites from long echo time spectroscopic imaging.

  6. Experimental 25Mg and 13C NMR and Computational Modeling Studies of Amorphous Mg-Ca Carbonates

    NASA Astrophysics Data System (ADS)

    Singer, J. W.; Yazaydin, A. O.; Kirkpatrick, R. J.; Saharay, M.; Bowers, G. M.

    2012-12-01

    Nuclear magnetic resonance (NMR) spectroscopy of synthetic Mg-Ca amorphous carbonates (AMC-ACC) provides direct, element specific structural information about these complicated phases. The 13C, 25Mg, and 43Ca resonances are typically broad and span the chemical shift ranges of all the crystalline polymorphs in the Ca-Mg-CO3-H2O system. In a fashion similar to our previous analysis of 43Ca NMR results for ACC,1 here we integrate new experimental 13C and 25Mg spectra obtained at 20T for samples with Mg/(Ca+Mg) ratios from x=0 to x=1 with quantum chemical calculations of the NMR parameters of the crystalline phases using CASTEP calculations, simulations of the spectra using the SIMPSON software, and classical molecular dynamics calculations. XRD and 13C NMR results are in general agreement with the one-phase/two-phase model of ACC-AMC derived from thermochemical work by others.2 13C-NMR spectra of amorphous materials having intermediate compositions can not be completely fit by mechanical mixing of ACC and AMC end members—requiring a degree of Ca/Mg solid solution. Amorphous samples in two-phase region crystallize to assemblages of dolomite-like (x~0.5) and hydromagnesite-like (x~1) defective structures, but we also observe aragonite co-nucleation in the presence of excess water, indicative of a more complex evolution. While 43Ca NMR of X-ray amorphous materials shows featureless, symmetric, Gaussian line shapes, the large quadrupole moment of 25Mg gives rise to superposition of several quadrupolar line shapes representing different local structural environments. Singularities of static Mg spectra are best explained by local environments similar to nequehonite, hydromagnesite, and landsfordite. The spectra can not exclude minor contributions from anhydrous phases dolomite, huntite, and magnesite. Additional sites having very large quadrupolar coupling and/or site asymmetry are not explained by any known reference phases. CITATIONS (1) Singer, J. W.; Yazaydin, A. O

  7. Evaluation of saffron (Crocus sativus L.) adulteration with plant adulterants by (1)H NMR metabolite fingerprinting.

    PubMed

    Petrakis, Eleftherios A; Cagliani, Laura R; Polissiou, Moschos G; Consonni, Roberto

    2015-04-15

    In the present work, a preliminary study for the detection of adulterated saffron and the identification of the adulterant used by means of (1)H NMR and chemometrics is reported. Authentic Greek saffron and four typical plant-derived materials utilised as bulking agents in saffron, i.e., Crocus sativus stamens, safflower, turmeric, and gardenia were investigated. A two-step approach, relied on the application of both OPLS-DA and O2PLS-DA models to the (1)H NMR data, was adopted to perform authentication and prediction of authentic and adulterated saffron. Taking into account the deficiency of established methodologies to detect saffron adulteration with plant adulterants, the method developed resulted reliable in assessing the type of adulteration and could be viable for dealing with extensive saffron frauds at a minimum level of 20% (w/w).

  8. Inclusion complex of benzocaine and β-cyclodextrin: 1H NMR and isothermal titration calorimetry studies

    NASA Astrophysics Data System (ADS)

    Mic, Mihaela; Pırnǎu, Adrian; Bogdan, Mircea; Turcu, Ioan

    2013-11-01

    The supramolecular structure of the inclusion complex of β-cyclodextrin with benzocaine in aqueous solution has been investigated by 1H NMR spectroscopy and isothermal titration nanocalorimetry (ITC). Analysis of 1H NMR data by continuous variation method indicates that the benzocaine: β-cyclodextrin inclusion complex occurs and has a 1:1 stoichiometry. Rotating frame NOE spectroscopy (ROESY) was used to ascertain the solution geometry of the host-guest complex which indicates that the benzocaine molecule was included with the aromatic ring into the cyclodextrin cavity. Although the affinity of benzocaine for cyclodextrin is relatively high, the association constant cannot be measured using ITC due to the low solubility of benzocaine in water.

  9. 1H NMR profiling as an approach to differentiate conventionally and organically grown tomatoes.

    PubMed

    Hohmann, Monika; Christoph, Norbert; Wachter, Helmut; Holzgrabe, Ulrike

    2014-08-20

    This study describes the approach of (1)H NMR profiling for the authentication of organically produced tomatoes (Solanum lycopersicum). Overall, 361 tomato samples of two different cultivars and four different producers were regularly analyzed during a 7 month period. The results of principal component analysis showed a significant trend for the separation between organically and conventionally produced tomatoes (p < 0.001 using the t test). Linear discriminant analysis demonstrated good discrimination between the growing regimens, and external validation showed 100% correctly classified tomato samples. Further validation studies, however, also disclosed unexpected differences between individual producers, which interfere with the aim of predicting the cultivation method, yet the results indicate significant differences between (1)H NMR spectra of organically and conventionally grown tomatoes.

  10. 1H NMR quantitative determination of photosynthetic pigments from green beans (Phaseolus vulgaris L.).

    PubMed

    Valverde, Juan; This, Hervé

    2008-01-23

    Using 1H nuclear magnetic resonance spectroscopy (1D and 2D), the two types of photosynthetic pigments (chlorophylls, their derivatives, and carotenoids) of "green beans" (immature pods of Phaseolus vulgaris L.) were analyzed. Compared to other analytical methods (light spectroscopy or chromatography), 1H NMR spectroscopy is a fast analytical way that provides more information on chlorophyll derivatives (allomers and epimers) than ultraviolet-visible spectroscopy. Moreover, it gives a large amount of data without prior chromatographic separation.

  11. 1H-NMR METABONOMICS ANALYSIS OF SERA DIFFERENTIATES BETWEEN MAMMARY TUMOR-BEARING MICE AND HEALTHY CONTROLS

    EPA Science Inventory

    Global analysis of 1H-NMR spectra of serum is an appealing approach for the rapid detection of cancer. To evaluate the usefulness of this method in distinguishing between mammary tumor-bearing mice and healthy controls, we conducted 1H-NMR metabonomic analyses on serum samples ob...

  12. Characterization of Acetate and Pyruvate Metabolism in Suspension Cultures of Zea mays by 13C NMR Spectroscopy

    PubMed Central

    Ashworth, Dennis J.; Lee, Rino Y.; Adams, Douglas O.

    1987-01-01

    Carbon-13 nuclear magnetic resonance (NMR) spectroscopy has been applied to the direct observation of acetate and pyruvate metabolism in suspension cultures of Zea mays (var Black Mexican Sweet). Growth of the corn cells in the presence of 2 millimolar [2-13C]acetate resulted in a rapid uptake of the substrate from the medium and initial labeling (0-4 hours) of primarily the intracellular glutamate and malate pools. Further metabolism of these intermediates resulted in labeling of glutamine, aspartate, and alanine. With [1-13C]acetate as the substrate very little incorporation into intermediary metabolites was observed in the 13C NMR spectra due to loss of the label as 13CO2. Uptake of [3-13C]pyruvate by the cells was considerably slower than with [2-13C]acetate; however, the labelling patterns were similar with the exception of increased [3-13C] alanine generation with pyruvate as the substrate. Growth of the cells for up to 96 hours with 2 millimolar [3-13C]pyruvate ultimately resulted in labeling of valine, leucine, isoleucine, threonine, and the polyamine putrescine. PMID:16665721

  13. Molecular composition of recycled organic wastes, as determined by solid-state {sup 13}C NMR and elemental analyses

    SciTech Connect

    Eldridge, S.M.; Chen, C.R.; Xu, Z.H.; Nelson, P.N.; Boyd, S.E.; Meszaros, I.; Chan, K.Y.

    2013-11-15

    Highlights: • Model estimated the molecular C components well for most RO wastes. • Molecular nature of organic matter in RO wastes varied widely. • Molecular composition by NMR modelling preferable to extraction techniques. • Some model shortcomings in estimating molecular composition of biochars. • Waste molecular composition important for carbon/nutrient outcomes in soil. - Abstract: Using solid state {sup 13}C NMR data and elemental composition in a molecular mixing model, we estimated the molecular components of the organic matter in 16 recycled organic (RO) wastes representative of the major materials generated in the Sydney basin area. Close correspondence was found between the measured NMR signal intensities and those predicted by the model for all RO wastes except for poultry manure char. Molecular nature of the organic matter differed widely between the RO wastes. As a proportion of organic C, carbohydrate C ranged from 0.07 to 0.63, protein C from <0.01 to 0.66, lignin C from <0.01 to 0.31, aliphatic C from 0.09 to 0.73, carbonyl C from 0.02 to 0.23, and char C from 0 to 0.45. This method is considered preferable to techniques involving imprecise extraction methods for RO wastes. Molecular composition data has great potential as a predictor of RO waste soil carbon and nutrient outcomes.

  14. Tautomeric ratio and prototropic equilibrium constants of tenoxicam, a 1H and 13C NMR theoretical and experimental study.

    PubMed

    Franco-Pérez, Marco; Moya-Hernández, Rosario; Rojas-Hernández, Alberto; Gutiérrez, Atilano; Gómez-Balderas, Rodolfo

    2011-11-24

    The determination of the micro-equilibrium prototropic constants is often a tough task when the tautomeric ratio favors one of the species or when the chemical exchange is not slow enough to allow the quantitative detection of the tautomeric species. There are just few experimental methods available to reveal the constants of the tautomeric micro-equilibriums; its applicability depends on the nature of the tautomeric system. A combination of experimental and quantum chemistry calculated (1)H and (13)C NMR chemical shifts is presented here to estimate the population of the species participating in the tautomeric equilibriums of the tenoxicam, an important anti-inflammatory drug. A multivariate fitting of a fraction-mol-weighted contribution model, for the NMR chemical shifts of the species in solution, was used to find the populations of the tautomers of tenoxicam. To consider and evaluate the effect of the solvent polarity on the tautomers' populations, experimental determinations were carried out in DMSO-d(6), in an equimolar DMSO-H(2)O mixture of deuterated solvents and in D(2)O. Additionally, by employing HYPNMR, it has been possible to refine the acid-base macroscopic constants of tenoxicam.

  15. Regression formulas for density functional theory calculated 1H and 13C NMR chemical shifts in toluene-d8.

    PubMed

    Konstantinov, Ivan A; Broadbelt, Linda J

    2011-11-10

    This study aimed at investigating the performance of a series of basis sets, density functional theory (DFT) functionals, and the IEF-PCM solvation model in the accurate calculation of (1)H and (13)C NMR chemical shifts in toluene-d(8). We demonstrated that, on a test set of 37 organic species with various functional moieties, linear scaling significantly improved the calculated shifts and was necessary to obtain more accurate results. Inclusion of a solvation model produced larger deviations from the experimental data as compared to the gas-phase calculations. Moreover, we did not find any evidence that very large basis sets were necessary to reproduce the experimental NMR data. Ultimately, we recommend the use of the BMK functional. For the (1)H shifts the use of the 6-311G(d) basis set gave linearly scaled mean unsigned (MU) and root-mean-square (rms) errors of 0.15 ppm and 0.21 ppm, respectively. For the calculation of the (13)C chemical shifts the 6-31G(d) basis set produced MUE of 1.82 ppm and RMSE of 3.29 ppm.

  16. Nanostructural effects on polymer and water dynamics in cellulose biocomposites: (2)h and (13)c NMR relaxometry.

    PubMed

    Terenzi, Camilla; Prakobna, Kasinee; Berglund, Lars A; Furó, István

    2015-05-11

    Improved moisture stability is desired in cellulose biocomposites. In order to clarify nanostructural effects, a new approach is presented where water and polymer matrix mobilities are characterized separately. Nanocomposites from cellulose nanofibers (CNF) in the xyloglucan (XG) biopolymer matrix are investigated at different hydration states. Films of XG, CNF, and CNF/XG composites are subjected to detailed (2)H and (13)C NMR relaxation studies. Since the (2)H NMR signal arises from heavy water and the (13)C signal from the polysaccharides, molecular water and polymer dynamics is for the first time investigated separately. In the neat components, (2)H transverse relaxation (T2) data are consistent with water clustering at the CNF fibril surfaces, but bulk spread of moisture in XG. The new method results in a description of water interaction with the nanoscale phases. At low hydration, water molecules at the CNF/XG interface exhibit higher water mobility than in neat CNF or XG, due to locally high water concentration. At the same time, CNF-associated interphase segments of XG show slower NMR-dynamics than that in neat XG.

  17. Area per lipid and cholesterol interactions in membranes from separated local-field (13)C NMR spectroscopy.

    PubMed

    Leftin, Avigdor; Molugu, Trivikram R; Job, Constantin; Beyer, Klaus; Brown, Michael F

    2014-11-18

    Investigations of lipid membranes using NMR spectroscopy generally require isotopic labeling, often precluding structural studies of complex lipid systems. Solid-state (13)C magic-angle spinning NMR spectroscopy at natural isotopic abundance gives site-specific structural information that can aid in the characterization of complex biomembranes. Using the separated local-field experiment DROSS, we resolved (13)C-(1)H residual dipolar couplings that were interpreted with a statistical mean-torque model. Liquid-disordered and liquid-ordered phases were characterized according to membrane thickness and average cross-sectional area per lipid. Knowledge of such structural parameters is vital for molecular dynamics simulations, and provides information about the balance of forces in membrane lipid bilayers. Experiments were conducted with both phosphatidylcholine (dimyristoylphosphatidylcholine (DMPC) and palmitoyloleoylphosphatidylcholine (POPC)) and egg-yolk sphingomyelin (EYSM) lipids, and allowed us to extract segmental order parameters from the (13)C-(1)H residual dipolar couplings. Order parameters were used to calculate membrane structural quantities, including the area per lipid and bilayer thickness. Relative to POPC, EYSM is more ordered in the ld phase and experiences less structural perturbation upon adding 50% cholesterol to form the lo phase. The loss of configurational entropy is smaller for EYSM than for POPC, thus favoring its interaction with cholesterol in raftlike lipid systems. Our studies show that solid-state (13)C NMR spectroscopy is applicable to investigations of complex lipids and makes it possible to obtain structural parameters for biomembrane systems where isotope labeling may be prohibitive.

  18. Biosynthesis, molecular structure, and domain architecture of potato suberin: a (13)C NMR study using isotopically labeled precursors.

    PubMed

    Yan, B; Stark, R E

    2000-08-01

    Although suberin in potato wound periderm is known to be a polyester containing long-chain fatty acids and phenolics embedded within the cell wall, many aspects of its molecular structure and polymer-polymer connectivities remain elusive. The present work combines biosynthetic incorporation of site-specifically (13)C-enriched acetates and phenylalanines with one- and two-dimensional solid-state (13)C NMR spectroscopic methods to monitor the developing suberin polymer. Exogenous acetate is found to be incorporated preferentially at the carboxyl end of the aliphatic carbon chains, suggesting addition during the later elongation steps of fatty acid synthesis. Carboxyl-labeled phenylalanine precursors provide evidence for the concurrent development of phenolic esters and of monolignols typical of lignin. Experiments with ring-labeled phenylalanine precursors demonstrate a predominance of sinapyl and guaiacyl structures among suberin's phenolic moieties. Finally, the analysis of spin-exchange (solid-state NOESY) NMR experiments in ring-labeled suberin indicates distances of no more than 0.5 nm between pairs of phenolic and oxymethine carbons, which are attributed to the aromatic-aliphatic polyester and the cell wall polysaccharide matrix, respectively. These results offer direct and detailed molecular information regarding the insoluble intermediates of suberin biosynthesis, indicate probable covalent linkages between moieties of its polyester and polysaccharide domains, and yield a clearer overall picture of this agriculturally important protective material.

  19. Benzenium ion chemistry on solid metal halide superacids: in situ {sup 13}C NMR experiments and theoretical calculations

    SciTech Connect

    Xu, T.; Barich, D.H.; Torres, P.D.; Haw, J.F.

    1997-01-15

    The benzenium, toluenium, and ethylbenzenium ions were synthesized on aluminium bromide by coadsorption of the precursors with either HBr or alkyl bromide. Principal components of the {sup 13}C chemical shift tensors for the ring carbons of these species were measured from magic angle spinning spectra. The benzenium ion was static at 77 K but underwent both proton scrambling and anisotropic rotation at 298 K as well as oligomerization at higher loadings. The para form of the toluenium ion was the dominant isomer at 77 K, but a temperature-dependent equilibrium between the para and ortho isomers was observed at 273 K. The energy calculations at MP4(fc,sdq)/ 6-311+G{sup *}//MP2/6-311+G{sup *} with thermal corrections resulted in good agreement between calculated and measured proton affinities for benzene, toluene, and ethylbenzene. For toluenium ion, the energies of the ortho and meta isomers were 1.2 and 5.4 kcal/mol, respectively, above the para isomer, consistent with the temperature-dependent {sup 13}C NMR spectra in the solid state. {sup 13}C chemical shift tensors calculated at the GIAO-MP2/tzp/dz//MP2/ 6-311+G{sup *} and GIAO-MP2/tzp/dz//B3LYP/6-311+G{sup *} levels of theory were in very close agreement with each other and generally in satisfactory agreement with experimental principal components. 64 refs., 8 figs., 4 tabs.

  20. Effect of chronic hypoglycaemia on glucose concentration and glycogen content in rat brain: a localized 13C NMR study

    PubMed Central

    Lei, Hongxia; Gruetter, Rolf

    2006-01-01

    While chronic hypoglycaemia has been reported to increase unidirectional glucose transport across the blood-brain barrier (BBB) and to increase GLUT1 expression at the endothelium, the effect on steady-state brain d-glucose and brain glycogen content is currently unknown. Brain glucose and glycogen concentrations were directly measured in vivo using localized 13C magnetic resonance spectroscopy (MRS) following 12-14 days of hypoglycaemia. Brain glucose content was significantly increased by 48%, which is consistent with an increase in the maximal glucose transport rate, Tmax, by 58% compared with the sham-treated animals. The localized 13C NMR measurements of brain glucose were directly validated by comparison with biochemically determined brain glucose content after rapid focused microwave fixation (1.4 s at 4 kW). Both in vivo MRS and biochemical measurements implied that brain glycogen content was not affected by chronic hypoglycaemia, consistent with brain glucose being a major factor controlling brain glycogen content. We conclude that the increased glucose transporter expression in chronic hypoglycaemia leads to increased brain glucose content at a given level of glycaemia. Such increased brain glucose concentrations can result in a lowered glycaemic threshold of counter-regulation observed in chronic hypoglycaemia. PMID:16987249

  1. Observation by sup 13 C NMR of the EPSP synthase tetrahedral intermediate bound to the enzyme active site

    SciTech Connect

    Anderson, K.S.; Sammons, R.D.; Leo, G.C.; Sikorski, J.A. ); Benesi, A.J.; Johnson, K.A. )

    1990-02-13

    Direct observation of the tetrahedral intermediate in the EPSP synthase reaction pathway was provided by {sup 13}C NMR by examining the species bound to the enzyme active site under internal equilibrium conditions and using (2-{sup 13}C)PEP as a spectroscopic probe. The tetrahedral center of the intermediate bound to the enzyme gave a unique signal appearing at 104 ppm. Separate signals were observed for free EPSP and EPSP bound to the enzyme in a ternary complex with phosphate. These peak assignments account for the quantitation of the species bound to the enzyme and liberated upon quenching with either triethylamine or base. A comparison of quenching with acid, base, or triethylamine was conducted. After long times of incubation during the NMR measurement, a signal at 107 ppm appeared. The compound giving rise to this resonance was isolated and identified as an EPSP ketal. The rate of formation of the EPSP ketal was very slow establishing that it is a side product of the normal enzymatic reaction. To look for additional signals that might arise from a covalent adduct which has been postulated to arise from reaction of enzyme with PEP, and NMR experiment was performed with an analogue of S3P lacking the 4- and 5-hydroxyl groups. All of these results reaffirm identification of the tetrahedral species as the only observable intermediate in the EPSP synthase reaction.

  2. Differential protonation and dynamic structure of doxylamine succinate in solution using 1H and 13C NMR.

    PubMed

    Somashekar, B S; Nagana Gowda, G A; Ramesha, A R; Khetrapal, C L

    2004-07-01

    A protonation and dynamic structural study of doxylamine succinate, a 1:1 salt of succinic acid with dimethyl-[2-(1-phenyl-1-pyridin-2-yl-ethoxy)ethyl]amine, in solution using one- and two-dimensional 1H and 13C NMR experiments at variable temperature and concentration is presented. The two acidic protons of the salt doxylamine succinate are in 'intermediate' exchange at room temperature, as evidenced by the appearance of a broad signal. This signal evolves into two distinct signals below about -30 degrees C. A two-dimensional 1H-1H double quantum filtered correlation experiment carried out at -55 degrees C shows protonation of one of the acidic protons to the dimethylamine nitrogen. A two-dimensional rotating frame 1H-1H NOE experiment at the same temperature reveals that the other proton remains with the succinate moiety. Comparison of the 1H and 13C chemical shifts and the 13C T1 relaxation times of the salt with those of the free base further substantiate the findings.

  3. Detection of Apoptosis and Necrosis in Normal Human Lung Cells Using 1H NMR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Shih, Chwen-Ming; Ko, Wun-Chang; Yang, Liang-Yo; Lin, Chien-Ju; Wu, Jui-Sheng; Lo, Tsui-Yun; Wang, Shwu-Huey; Chen, Chien-Tsu

    2005-05-01

    This study aimed to detect apoptosis and necrosis in MRC-5, a normal human lung cell line, by using noninvasive proton nuclear magnetic resonance (1H NMR). Live MRC-5 cells were processed first for 1H NMR spectroscopy; subsequently their types and the percentage of cell death were assessed on a flow cytometer. Cadmium (Cd) and mercury (Hg) induced apoptosis and necrosis in MRC-5 cells, respectively, as revealed by phosphatidylserine externalization on a flow cytometer. The spectral intensity ratio of methylene (CH2) resonance (at 1.3 ppm) to methyl (CH3) resonance (at 0.9 ppm) was directly proportional to the percentage of apoptosis and strongly and positively correlated with PI staining after Cd treatment (r2 = 0.9868, P < 0.01). In contrast, this ratio only increased slightly within 2-h Hg treatment, and longer Hg exposure failed to produce further increase. Following 2-h Hg exposure, the spectral intensity of choline resonance (at 3.2 ppm) was abolished, but this phenomenon was absent in Cd-induced apoptosis. These findings together demonstrate that 1H NMR is a novel tool with a quantitative potential to distinguish apoptosis from necrosis as early as the onset of cell death in normal human lung cells.

  4. (1)H NMR metabonomic analysis in renal cell carcinoma: a possible diagnostic tool.

    PubMed

    Zira, Athina N; Theocharis, Stamatios E; Mitropoulos, Dionisios; Migdalis, Vasilios; Mikros, Emmanuel

    2010-08-06

    (1)H NMR based metabonomic approach was applied in order to monitor the alterations of plasma metabolic profile in Renal Cell Carcinoma (RCC) patients and controls. (1)H NMR spectra of plasma samples from 32 RCC patients and 13 controls (patients exhibiting benign urologic disease) were recorded and analyzed using multivariate statistical techniques. Alterations in the levels of LDL/VLDL, NAC, lactate, and choline were observed between RCC patients and controls discriminating these groups in Principal Component Analysis (PCA) plots. Post OSC PLS-DA presented a satisfactory clustering between T1 with T3 RCC patients. Decrease in plasma lipid concentrations in RCC patients was verified using conventional clinical chemistry analysis. The results suggest that combination of (1)H NMR spectroscopy with PCA has potential in cancer diagnosis; however, a limitation of the method to monitor RCC is that major biomarkers revealed (lipoproteins and choline) in this metabolic profile are not unique to RCC but may be the result of the presence of any malignancy.

  5. Investigation of 1H NMR chemical shifts of organic dye with hydrogen bonds and ring currents.

    PubMed

    Park, Sung Soo; Won, Yong Sun; Lee, Woojin; Kim, Jae Hong

    2011-04-07

    The (1)H NMR chemical shifts were theoretically computed for the organic dyes 2-(2,6-dimethyl-4H-pyran-4-ylidene)-malononitrile (1), cyano-(2,6-dimethyl-4H-pyran-4-ylidene)-acetic acid methyl ester (2), 2-(2,6-bis(4-(dimethylamino)styryl)-4H-pyran-4-ylidene)-malononitrile (3), and methyl 2-(2,6-bis(4-(dimethylamino)styryl)-4H-pyran-4-ylidene)-2-cyanoacetate (4) at the GIAO/B3LYP/6-311++G(d,p)//B3LYP/6-311++G(d,p) level of theory. Moreover, the intramolecular rotational barriers of the molecules were calculated to evaluate the internal flexibility with respect to the torsional degrees of freedom, and the nuclear-independent chemical shifts (NICS) were employed to analyze the ring currents. The difference was explained in terms of intramolecular hydrogen bonds and ring currents of the molecules. The (1)H NMR spectra were reproduced by experiments for the comparison with computationally constructed data. Our results suggest a good guideline in interpreting (1)H NMR chemical shifts using computational methods and furthermore a reliable perspective for designing molecular structures.

  6. A Discovery-Based Hydrochlorination of Carvone Utilizing a Guided-Inquiry Approach to Determine the Product Structure from [superscript 13]C NMR Spectra

    ERIC Educational Resources Information Center

    Pelter, Michael W.; Walker, Natalie M.

    2012-01-01

    This experiment describes a discovery-based method for the regio- and stereoselective hydrochlorination of carvone, appropriate for a 3-h second-semester organic chemistry laboratory. The product is identified through interpretation of the [superscript 13]C NMR and DEPT spectra are obtained on an Anasazi EFT-60 at 15 MHz as neat samples. A…

  7. Complete 1H and 13C NMR assignments and Z/E-stereoconfiguration determination of isomers of 1,4-diketone derivatives.

    PubMed

    Xu, Guohua; Yin, Guodong; Guo, Wenbo; Wu, Anxin; Cui, Yanfang

    2008-01-01

    Complete 1H and 13C NMR assignments and Z/E-stereoconfiguration determination for a series of new isomers of 1,4-diketone derivatives obtained via self-sorting tandem reaction were accomplished by means of one- and two-dimentional NMR experiments including 1H, 13C, gCOSY, gHSQC, gHMBC, and NOESY.

  8. 1H and 13C NMR signal assignment of cucurbitacin derivatives from Citrullus colocynthis (L.) Schrader and Ecballium elaterium L. (Cucurbitaceae).

    PubMed

    Seger, Christoph; Sturm, Sonja; Mair, Maria-Elisabeth; Ellmerer, Ernst P; Stuppner, Hermann

    2005-06-01

    2D NMR-derived 1H and 13C NMR signal assignments of six structurally closely related cucurbitacin derivatives are presented. The investigated 2-O-beta-D-glucopyranosylcucurbitacins I, J, K, and L were obtained from Citrullus colocynthis (L.) Schrader whereas the aglyca cucurbitacin E and I were isolated from Ecballium elaterium L.

  9. Identifying metabolites related to nitrogen mineralisation using 1H NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    . T McDonald, Noeleen; Graham, Stewart; Watson, Catherine; Gordon, Alan; Lalor, Stan; Laughlin, Ronnie; Elliott, Chris; . P Wall, David

    2015-04-01

    Exploring new analysis techniques to enhance our knowledge of the various metabolites within our soil systems is imperative. Principally, this knowledge would allow us to link key metabolites with functional influences on critical nutrient processes, such as the nitrogen (N) mineralisation in soils. Currently there are few studies that utilize proton nuclear magnetic resonance spectroscopy (1H NMR) to characterize multiple metabolites within a soil sample. The aim of this research study was to examine the effectiveness of 1H NMR for isolating multiple metabolites that are related to the mineralizable N (MN) capacity across a range of 35 Irish grassland soils. Soils were measured for MN using the standard seven day anaerobic incubation (AI-7). Additionally, soils were also analysed for a range of physio-chemical properties [e.g. total N, total C, mineral N, texture and soil organic matter (SOM)]. Proton NMR analysis was carried on these soils by extracting with 40% methanol:water, lyophilizing and reconstituting in deuterium oxide and recording the NMR spectra on a 400MHz Bruker AVANCE III spectrometer. Once the NMR data were spectrally processed and analysed using multivariate statistical analysis, seven metabolites were identified as having significant relationships with MN (glucose, trimethylamine, glutamic acid, serine, aspartic acid, 4-aminohippuirc acid and citric acid). Following quantification, glucose was shown to explain the largest percentage variability in MN (72%). These outcomes suggest that sources of labile carbon are essential in regulating N mineralisation and the capacity of plant available N derived from SOM-N pools in these soils. Although, smaller in concentration, the amino acids; 4-aminohippuirc acid, glutamic acid and serine also significantly (P<0.05) explained 43%, 27% and 19% of the variability in MN, respectively. This novel study highlights the effectiveness of using 1H NMR as a practical approach to profile multiple metabolites in

  10. [1H-NMR studies of the ACTH-like immunoregulatory peptides].

    PubMed

    Khristoforov, V S; Kutyshenko, V P; Abramov, V M; Zav'ialov, V P

    1997-01-01

    A comparative study of the conformational and dynamics properties of the ACTH-like linear peptides, sequences of which correspond to amino acid residues 11-20 of the heavy chain of human immunoglobulin G1 Eu, residues 78-85 of human pro-interleukin-1 alpha and site 10-18 of human ACTH, was performed in aqueous solution and dimethylsulfoxide by 1H-NMR spectroscopy at 400 MHz. The peptides were shown to possess an unordered unfolded flexible conformation in aqueous solution. The revealed structural and dynamic features of the peptides are discussed together with biological activity of this class of compounds.

  11. Photosensitized Peroxidation of Lipids: An Experiment Using 1H-NMR

    NASA Astrophysics Data System (ADS)

    Smith, Marion W.; Brown, Renee; Smullin, Steven; Eager, Jon

    1997-12-01

    The photoperoxidation of methyl linoleate, using 5,10,15,20-tetraphenyl porphyrin as photosensitizer, was monitored by 60 MHz 1H-NMR. Samples were irradiated for 10-24 hours in front of a 15 W fluorescent light, and NMR signals in the 5-6 ppm and 10-11 ppm region of the spectrum indicated peroxidation products were formed. The absorption of oxygen from the air was measured by attaching the sample tube to a gas burette. When vitamin E was added to the mixture the extent of peroxidation was reduced, showing the protective effect of the antioxidant. These experiments are appropriate for students of biochemistry

  12. Intermolecular Interactions between Eosin Y and Caffeine Using 1H-NMR Spectroscopy

    PubMed Central

    Okuom, Macduff O.; Wilson, Mark V.; Jackson, Abby; Holmes, Andrea E.

    2014-01-01

    DETECHIP has been used in testing analytes including caffeine, cocaine, and tetrahydrocannabinol (THC) from marijuana, as well as date rape and club drugs such as flunitrazepam, gamma-hydroxybutyric acid (GHB), and methamphetamine. This study investigates the intermolecular interaction between DETECHIP sensor eosin Y (DC1) and the analyte (caffeine) that is responsible for the fluorescence and color changes observed in the actual array. Using 1H-NMR, 1H-COSY, and 1H-DOSY NMR methods, a proton exchange from C-8 of caffeine to eosin Y is proposed. PMID:25018772

  13. 1H NMR investigation of self-association of vanillin in aqueous solution

    NASA Astrophysics Data System (ADS)

    Bogdan, Mircea; Floare, Calin G.; Pîrnau, Adrian

    2009-08-01

    A self-association of vanillin have been studied by 1H NMR spectroscopy using the analysis of proton chemical shifts changes in aqueous solution as a function of concentration. The experimental results have been analysed using indefinite non-cooperative and cooperative models of molecular self-association, enabling the determination of equilibrium constants, parameters of cooperativity and the limiting values of vanillin proton chemical shifts in the complex. It was found that the dimer formation creates energetically favourable conditions for subsequent molecular association.

  14. High-resolution /sup 1/H NMR study of the solution structure of alamethicin

    SciTech Connect

    Esposito, G.; Carver, J.A.; Boyd, J.; Campbell, I.D.

    1987-02-24

    A /sup 1/H NMR study of the peptide alamethicin, which forms voltage-gated ion channels in membranes, is described. The molecule was studied in methanol as a function of temperature and pH. A complete assignment of the spectra is given, including several stereospecific assignments. Alamethicin was found to have a structure substantially similar to the crystal although, in solution, the C-terminal dipeptide adopts a somewhat extended conformation. The overall conformation was insensitive to the ionization of the side chain of the ionizable group, Glu-18.

  15. Investigations of La Rioja terroir for wine production using 1H NMR metabolomics.

    PubMed

    López-Rituerto, Eva; Savorani, Francesco; Avenoza, Alberto; Busto, Jesús H; Peregrina, Jesús M; Engelsen, Søren Balling

    2012-04-04

    In this study, La Rioja wine terroir was investigated by the use of (1)H NMR metabolomics on must and wine samples. Rioja is a small wine region in central northern Spain which can geographically be divided into three subareas (Rioja Alta, Rioja Baja, and Rioja Alavesa). The winemaking process from must, through alcoholic and malolactic fermentation, was followed by NMR metabolomics and chemometrics of nine wineries in the Rioja subareas (terroirs). Application of interval extended canonical variate analysis (iECVA) showed discriminative power between wineries which are geographically very close. Isopentanol and isobutanol compounds were found to be key biomarkers for this differentiation.

  16. 1H NMR spectral studies on the polymerization mechanism of indole and its derivatives

    NASA Astrophysics Data System (ADS)

    Xu, Jingkun; Hou, Jian; Zhou, Weiqiang; Nie, Guangming; Pu, Shouzhi; Zhang, Shusheng

    2006-03-01

    The existence of N sbnd H bond according to the hydrogen nuclear magnetic resonance ( 1H NMR) spectra of polyindole and its derivatives, such as poly(5-bromoindole), poly(5-cyanoindole), poly(5-nitroindole), poly(5-methylindole), proved polymerization of high-quality polyindoles, which were electrosynthesized from middle strong Lewis acid boron trifluoride diethyl etherate (BFEE) and its mixed electrolytes with additional diethyl ether, occurred at 2,3-position. The elongation of the conjugation length made the chemical shift of all the protons of polyindoles to lower field in comparison with those of monomers.

  17. (1)H NMR spectra dataset and solid-state NMR data of cowpea (Vigna unguiculata).

    PubMed

    Alves Filho, Elenilson G; Silva, Lorena M A; Teofilo, Elizita M; Larsen, Flemming H; de Brito, Edy S

    2017-04-01

    In this article the NMR data from chemical shifts, coupling constants, and structures of all the characterized compounds were provided, beyond a complementary PCA evaluation for the corresponding manuscript (E.G. Alves Filho, L.M.A. Silva, E.M. Teofilo, F.H. Larsen, E.S. de Brito, 2017) [3]. In addition, a complementary assessment from solid-state NMR data was provided. For further chemometric analysis, numerical matrices from the raw (1)H NMR data were made available in Microsoft Excel workbook format (.xls).

  18. Water distribution in brine salted cod (Gadus morhua) and salmon (Salmo salar): a low-field 1H NMR study.

    PubMed

    Aursand, Ida G; Gallart-Jornet, Lorena; Erikson, Ulf; Axelson, David E; Rustad, Turid

    2008-08-13

    Low-field (LF) (1)H NMR T 2 relaxation measurements were used to study changes in water distribution in lean (Atlantic cod) and fatty (Atlantic salmon) fish during salting in 15% NaCl and 25% NaCl brines. The NMR data were treated by PCA, continuous distribution analysis, and biexponential fitting and compared with physicochemical data. Two main water pools were observed in unsalted fish, T 21, with relaxation times in the range 20-100 ms, and T 22, with relaxation times in the range 100-300 ms. Pronounced changes in T 2 relaxation data were observed during salting, revealing changes in the water properties. Salting in 15% brine lead to a shift toward longer relaxation times, reflecting increased water mobility, whereas, salting in saturated brines had the opposite effect. Water mobility changes were observed earlier in the salting process for cod compared to salmon. Good linear correlations ( F

  19. Interaction between a recombinant prion protein and organo-mineral complexes as evidenced by CPMAS 13C-NMR

    NASA Astrophysics Data System (ADS)

    Russo, F.; Scotti, R.; Gianfreda, L.; Conte, P.; Rao, M. A.

    2009-04-01

    Prion proteins (PrP) are the main responsible for Transmissible Spongiform Encephalopathies (TSE). The TSE etiological agent is a misfolded form of the normal cellular prion protein. The amyloidal aggregates accumulated in the brain of infected animals and mainly composed of PrPSc exhibit resistance to protease attack and many conventional inactivating procedures. The prion protein diseases cause an environmental issue because the environment and in particular the soil compartment can be contaminated and then become a potential reservoir and diffuser of TSEs infectivity as a consequence of (i) accidental dispersion from storage plants of meat and bone meal, (ii) incorporation of contaminated material in fertilizers, (iii) possible natural contamination of pasture soils by grazing herds, and (v) burial of carcasses. The environmental problem can be even more relevant because very low amounts of PrPSc are able to propagate the disease. Several studies evidenced that infectious prion protein remains active in soils for years. Contaminated soils result, thus, a possible critical route of TSE transmission in wild animals. Soil can also protect prion protein toward degradation processes due to the presence of humic substances and inorganic components such as clays. Mineral and organic colloids and the more common association between clay minerals and humic substances can contribute to the adsorption/entrapment of molecules and macromolecules. The polymerization of organic monomeric humic precursors occurring in soil in the presence of oxidative enzymes or manganese and iron oxides, is considered one of the most important processes contributing to the formation of humic substances. The process is very fast and produces a population of polymeric products of different molecular structures, sizes, shapes and complexity. Other molecules and possibly biomacromolecules such as proteins may be involved. The aim of the present work was to study by CPMAS 13C-NMR the interactions

  20. Luminescence dynamics and {sup 13}C NMR characteristics of dinuclear complexes exhibiting coupled lanthanide(III) cation pairs

    SciTech Connect

    Matthews, K.D.; Bailey-Folkes, S.A.; Kahwa, I.A.

    1992-08-20

    Luminescence and cross-polarization magic angle spinning (CP-MAS) {sup 13}C NMR properties of lanthanide dinuclear macrocyclic complexes of a compartmental Schiff base chelate (1) derived from the condensation of 2,6-diformyl-p-cresol and 3,6-dioxa-1,8-octanediamine are reported. The Schiff base chromophore in 1 is a strong light absorber and an efficient sensitizer for intense Tb{sup 3+}({sup 5}D{sub 4}) and Eu{sup 3+}({sup 5}D{sub 0})(T < 110 K ) emission which does not exhibit self-quenching effects. Emission from Tb{sup 3+} is sensitized by the ligand singlet state; in striking contrast, Eu{sup 3+} emission is sensitized by the triplet state and reveals an unusual nonradiative quenching process at T > 110 K with a thermal barrier of {approx} 2300 cm{sup {minus}1}. Weak emission is observed from Dy{sup 3+}({sup 4}F{sub 9/2}), Sm{sup 3+}({sup 4}G{sub 5/2}), and Pr{sup 3+}({sup 1}D{sub 2}) diluted in Gd{sup 3+} (i.e., from Gd{sup 3+}-Ln{sup 3+} heteropairs, Ln = Pr, Sm, Dy). Intramolecular metal-metal (Ln-Ln = 4 {Angstrom}) interactions account for the greatly quenched emission from Sm{sup 3+}-Sm{sup 3+} and Dy{sup 3+}-Dy{sup 3+} homopairs compared to Gd{sup 3+}-Ln heteropairs (Ln = Sm, Dy). Gd{sup 3+}-Ln{sup 3+} emission lifetimes at 77 K are 1610 (Tb{sup 3+}), 890 (Eu{sup 3+}), 14 (Dy{sup 3+}) and {approx} 13 {mu}s (Sm{sup 3+}). Nonradiative relaxation processes at 77 K in dilute Ln{sup 3+}:Gd{sub 2}1(NO{sub 3}){sub 4}{center_dot}H{sub 2}O, being temperature independent for Sm{sup 3+} and Eu{sup 3+} but temperature dependent for Tb{sup 3+}, follow the energy gap law with {alpha} {approx} - 10{sup {minus}3} cm and B {approx} 2 x 10{sup 8} s{sup {minus}1}. CP-MAS data show paramagnetic broadening of {sup 13}C resonances which increases with the magnetic moment of Ln{sup 3+}. Surprisingly, no significant shifts in resonance positions corresponding to the changing nature of paramagnetic Ln{sup 3+} ions are observed. 43 refs., 8 figs., 2 tabs.

  1. Low resolution 1H NMR assignment of proton populations in pound cake and its polymeric ingredients.

    PubMed

    Luyts, A; Wilderjans, E; Waterschoot, J; Van Haesendonck, I; Brijs, K; Courtin, C M; Hills, B; Delcour, J A

    2013-08-15

    Based on a model system approach, five different proton populations were distinguished in pound cake crumb using one dimensional low resolution (1)H NMR spectroscopy. In free induction decay (FID) measurements, proton populations were assigned to (i) non-exchanging CH protons of crystalline starch, proteins and crystalline fat and (ii) non-exchanging CH protons of amorphous starch and gluten, which are in little contact with water. In Carr-Purcell-Meiboom-Gill (CPMG) measurements, three proton populations were distinguished. The CPMG population with the lowest mobility and the FID population with the highest mobility represent the same proton population. The two CPMG proton populations with the highest mobility were assigned to exchanging protons (i.e., protons of water, starch, gluten, egg proteins and sugar) and protons of lipids (i.e., protons of egg yolk lipids and amorphous lipid fraction of margarine) respectively. Based on their spin-lattice relaxation times (T1), two dimensional (1)H NMR spectroscopy further resolved the two proton populations with the highest mobility into three and two proton populations, respectively.

  2. (1)H-NMR-based metabolomic studies of bisphenol A in zebrafish (Danio rerio).

    PubMed

    Yoon, Changshin; Yoon, Dahye; Cho, Junghee; Kim, Siwon; Lee, Heonho; Choi, Hyeonsoo; Kim, Suhkmann

    2017-04-03

    Proton nuclear magnetic resonance ((1)H-NMR) spectroscopy was used to study the response of zebrafish (Danio rerio) to increasing concentrations of bisphenol A (4,4'-(propane-2,2-diyl)diphenol, BPA). Orthogonal partial least squares discriminant analysis (OPLS-DA) was applied to detect aberrant metabolomic profiles after 72 h of BPA exposure at all levels tested (0.01, 0.1, and 1.0 mg/L). The OPLS-DA score plots showed that BPA exposure caused significant alterations in the metabolome. The metabolomic changes in response to BPA exposure generally exhibited nonlinear patterns, with the exception of reduced levels of several metabolites, including glutamine, inosine, lactate, and succinate. As the level of BPA exposure increased, individual metabolite patterns indicated that the zebrafish metabolome was subjected to severe oxidative stress. Interestingly, ATP levels increased significantly at all levels of BPA exposure. In the present study, we demonstrated the applicability of (1)H-NMR-based metabolomics to identify the discrete nature of metabolic changes.

  3. Sudan dyes in adulterated saffron (Crocus sativus L.): Identification and quantification by (1)H NMR.

    PubMed

    Petrakis, Eleftherios A; Cagliani, Laura R; Tarantilis, Petros A; Polissiou, Moschos G; Consonni, Roberto

    2017-02-15

    Saffron, the dried red stigmas of Crocus sativus L., is considered as one of the most expensive spices worldwide, and as such, it is prone to adulteration. This study introduces an NMR-based approach to identify and determine the adulteration of saffron with Sudan I-IV dyes. A complete (1)H and (13)C resonance assignment for Sudan I-IV, achieved by two-dimensional homonuclear and heteronuclear NMR experiments, is reported for the first time. Specific different proton signals for the identification of each Sudan dye in adulterated saffron can be utilised for quantitative (1)H NMR (qHNMR), a well-established method for quantitative analysis. The quantification of Sudan III, as a paradigm, was performed in varying levels (0.14-7.1g/kg) by considering the NMR signal occurring at 8.064ppm. The high linearity, accuracy and rapidity of investigation enable high resolution (1)H NMR spectroscopy to be used for evaluation of saffron adulteration with Sudan dyes.

  4. [Study on three different species tibetan medicine sea buckthorn by 1H-NMR-based metabonomics].

    PubMed

    Su, Yong-Wen; Tan, Er; Zhang, Jing; You, Jia-Li; Liu, Yue; Liu, Chuan; Zhou, Xiang-Dong; Zhang, Yi

    2014-11-01

    The 1H-NMR fingerprints of three different species tibetan medicine sea buckthorn were established by 1H-HMR metabolomics to find out different motablism which could provide a new method for the quality evaluation of sea buckthorn. The obtained free induction decay (FID) signal will be imported into MestReNova software and into divide segments. The data will be normalized and processed by principal component analysis and.partial least squares discriminant analysis to perform pattern recognition. The results showed that 25 metabolites belonging to different chemical types were detected from sea buckthorn,including flavonoids, triterpenoids, amino acids, carbohydrates, fatty acids, etc. PCA and PLS-DA analysis showed three different varietiest of sea buckthorn that can be clearly separated by the content of L-quebrachitol, malic acid and some unidentified sugars, which can be used as the differences metabolites of three species of sea buckthorn. 1H-NMR-based metabonomies method had a holistic characteristic with sample preparation and handling. The results of this study can offer an important reference for the species identification and quality control of sea buckthorn.

  5. Metabolomic Investigations of American Oysters Using 1H-NMR Spectroscopy

    PubMed Central

    Tikunov, Andrey P.; Johnson, Christopher B.; Lee, Haakil; Stoskopf, Michael K.; Macdonald, Jeffrey M.

    2010-01-01

    The Eastern oyster (Crassostrea virginica) is a useful, robust model marine organism for tissue metabolism studies. Its relatively few organs are easily delineated and there is sufficient understanding of their functions based on classical assays to support interpretation of advanced spectroscopic approaches. Here we apply high-resolution proton nuclear magnetic resonance (1H NMR)-based metabolomic analysis to C. virginica to investigate the differences in the metabolic profile of different organ groups, and magnetic resonance imaging (MRI) to non-invasively identify the well separated organs. Metabolites were identified in perchloric acid extracts of three portions of the oyster containing: (1) adductor muscle, (2) stomach and digestive gland, and (3) mantle and gills. Osmolytes dominated the metabolome in all three organ blocks with decreasing concentration as follows: betaine > taurine > proline > glycine > ß-alanine > hypotaurine. Mitochondrial metabolism appeared most pronounced in the adductor muscle with elevated levels of carnitine facilitating ß-oxidation, and ATP, and phosphoarginine synthesis, while glycogen was elevated in the mantle/gills and stomach/digestive gland. A biochemical schematic is presented that relates metabolites to biochemical pathways correlated with physiological organ functions. This study identifies metabolites and corresponding 1H NMR peak assignments for future NMR-based metabolomic studies in oysters. PMID:21116407

  6. Authentication of beef versus horse meat using 60 MHz 1H NMR spectroscopy.

    PubMed

    Jakes, W; Gerdova, A; Defernez, M; Watson, A D; McCallum, C; Limer, E; Colquhoun, I J; Williamson, D C; Kemsley, E K

    2015-05-15

    This work reports a candidate screening protocol to distinguish beef from horse meat based upon comparison of triglyceride signatures obtained by 60 MHz (1)H NMR spectroscopy. Using a simple chloroform-based extraction, we obtained classic low-field triglyceride spectra from typically a 10 min acquisition time. Peak integration was sufficient to differentiate samples of fresh beef (76 extractions) and horse (62 extractions) using Naïve Bayes classification. Principal component analysis gave a two-dimensional "authentic" beef region (p=0.001) against which further spectra could be compared. This model was challenged using a subset of 23 freeze-thawed training samples. The outcomes indicated that storing samples by freezing does not adversely affect the analysis. Of a further collection of extractions from previously unseen samples, 90/91 beef spectra were classified as authentic, and 16/16 horse spectra as non-authentic. We conclude that 60 MHz (1)H NMR represents a feasible high-throughput approach for screening raw meat.

  7. Toxicity assessment of Arisaematis Rhizoma in rats by a (1)H NMR-based metabolomics approach.

    PubMed

    Dong, Ge; Wang, Junsong; Guo, Pingping; Wei, Dandan; Yang, Minghua; Kong, Lingyi

    2015-02-01

    Arisaematis Rhizoma (AR), a famous traditional Chinese medicine, has been widely used in Asia over thousands of years. Documented with noticeable toxicity in ancient books, AR has been used to treat various diseases in the clinic. Therefore, it is important to assess the toxicity of AR dynamically and holistically. In this study, a (1)H NMR-based metabolomics approach complemented with serum chemistry and histopathology has been applied to investigate the toxicity of AR. Rats were intragastrically administered with AR (0, 0.5 and 1 g kg(-1) body weight) for 30 days, and serum and urine samples were collected. Their (1)H NMR profiles were analyzed by multivariate pattern recognition techniques to denote metabolic variations induced by AR, and 13 metabolites in urine and 6 metabolites in serum were significantly altered, which suggested that disturbances in energy metabolism, perturbation of the gut microflora environment, membrane damage, folate deficiency and injury of kidneys are produced by AR. Histopathology showed a slight vacuolization of the glomerular matrix and edema of renal tubular epithelial cells in kidneys of AR administered rats, which were evidenced by increased levels of blood urea nitrogen and creatinine in serum chemistry. Our results indicated that oral administration of crude AR was found to induce slight renal toxicity. Therefore, precautions should be made to monitor the potential nephrotoxicity of AR in clinical use. The metabolomics approach provided a promising tool for the study and better understanding of TCM-induced toxicity dynamically and holistically.

  8. Authentication of beef versus horse meat using 60 MHz 1H NMR spectroscopy

    PubMed Central

    Jakes, W.; Gerdova, A.; Defernez, M.; Watson, A.D.; McCallum, C.; Limer, E.; Colquhoun, I.J.; Williamson, D.C.; Kemsley, E.K.

    2015-01-01

    This work reports a candidate screening protocol to distinguish beef from horse meat based upon comparison of triglyceride signatures obtained by 60 MHz 1H NMR spectroscopy. Using a simple chloroform-based extraction, we obtained classic low-field triglyceride spectra from typically a 10 min acquisition time. Peak integration was sufficient to differentiate samples of fresh beef (76 extractions) and horse (62 extractions) using Naïve Bayes classification. Principal component analysis gave a two-dimensional “authentic” beef region (p = 0.001) against which further spectra could be compared. This model was challenged using a subset of 23 freeze–thawed training samples. The outcomes indicated that storing samples by freezing does not adversely affect the analysis. Of a further collection of extractions from previously unseen samples, 90/91 beef spectra were classified as authentic, and 16/16 horse spectra as non-authentic. We conclude that 60 MHz 1H NMR represents a feasible high-throughput approach for screening raw meat. PMID:25577043

  9. Isotopic 13C NMR spectrometry to assess counterfeiting of active pharmaceutical ingredients: site-specific 13C content of aspirin and paracetamol.

    PubMed

    Silvestre, Virginie; Mboula, Vanessa Maroga; Jouitteau, Catherine; Akoka, Serge; Robins, Richard J; Remaud, Gérald S

    2009-10-15

    Isotope profiling is a well-established technique to obtain information about the chemical history of a given compound. However, the current methodology using IRMS can only determine the global (13)C content, leading to the loss of much valuable data. The development of quantitative isotopic (13)C NMR spectrometry at natural abundance enables the measurement of the (13)C content of each carbon within a molecule, thus giving simultaneous access to a number of isotopic parameters. When it is applied to active pharmaceutical ingredients, each manufactured batch can be characterized better than by IRMS. Here, quantitative isotopic (13)C NMR is shown to be a very promising and effective tool for assessing the counterfeiting of medicines, as exemplified by an analysis of aspirin (acetylsalicylic acid) and paracetamol (acetaminophen) samples collected from pharmacies in different countries. It is proposed as an essential complement to (2)H NMR and IRMS.

  10. A study of the molecular conformations and the vibrational, 1H and 13C NMR spectra of the anticancer drug tamoxifen and triphenylethylene

    NASA Astrophysics Data System (ADS)

    Badawi, Hassan M.; Khan, Ibrahim

    2016-08-01

    The structural stability and the vibrational spectra of the anticancer drug tamoxifen and triphenylethylene were investigated by the DFT B3LYP/6-311G (d,p) calculations. Tamoxifen and triphenylethylene were predicted to exist predominantly as non-planar structures. The vibrational frequencies and the 1H and 13C NMR chemical shifts of the low energy structures of tamoxifen and triphenylethylene were computed at the DFT B3LYP level of theory. Complete vibrational assignments were provided by combined theoretical and experimental data of tamoxifen and triphenylethylene. The 1H and 13C NMR spectra of both molecules were interpreted by experimental and DFT calculated chemical shifts of the two molecules. The RMSD between experimental and theoretical 1H and 13C chemical shifts for tamoxifen is 0.29 and 4.72 ppm, whereas for triphenylethylene, it is 0.16 and 2.70 ppm, respectively.

  11. Characterization of organic matter in sediment cores of the Todos os Santos Bay, Bahia, Brazil, by elemental analysis and 13C NMR.

    PubMed

    Costa, A B; Novotny, E H; Bloise, A C; de Azevedo, E R; Bonagamba, T J; Zucchi, M R; Santos, V L C S; Azevedo, A E G

    2011-08-01

    The impact of human activity on the sediments of Todos os Santos Bay in Brazil was evaluated by elemental analysis and 13C Nuclear Magnetic Resonance (13C NMR). This article reports a study of six sediment cores collected at different depths and regions of Todos os Santos Bay. The elemental profiles of cores collected on the eastern side of Frades Island suggest an abrupt change in the sedimentation regime. Autoregressive Integrated Moving Average (ARIMA) analysis corroborates this result. The range of depths of the cores corresponds to about 50 years ago, coinciding with the implantation of major onshore industrial projects in the region. Principal Component Analysis of the 13C NMR spectra clearly differentiates sediment samples closer to the Subaé estuary, which have high contents of terrestrial organic matter, from those closer to a local oil refinery. The results presented in this article illustrate several important aspects of environmental impact of human activity on this bay.

  12. Mechanism of formation of humus coatings on mineral surfaces 3. Composition of adsorbed organic acids from compost leachate on alumina by solid-state 13C NMR

    USGS Publications Warehouse

    Wershaw, R. L.; Llaguno, E.C.; Leenheer, J.A.

    1996-01-01

    The adsorption of compost leachate DOC on alumina is used as a model for elucidation of the mechanism of formation of natural organic coatings on hydrous metal oxide surfaces in soils and sediments. Compost leachate DOC is composed mainly of organic acid molecules. The solid-state 13C NMR spectra of these organic acids indicate that they are very similar in composition to aquatic humic substances. Changes in the solid-state 13C NMR spectra of compost leachate DOC fractions adsorbed on alumina indicate that the DOC molecules are most likely adsorbed on metal oxide surfaces through a combination of polar and hydrophobic interaction mechanisms. This combination of polar and hydrophobic mechanism leads to the formation of bilayer coatings of the leachate molecules on the oxide surfaces.

  13. Solute-solvent interactions of acid-1,4-dioxane mixtures-By dielectric, FTIR, UV-vis and 13C NMR spectrometric methods.

    PubMed

    Arivazhagan, G; Parthipan, G; Thenappan, T

    2009-11-01

    Results of the dielectric studies carried out on the binary mixture of n-butyric and caprylic acids with 1,4-dioxane over the entire composition range and at temperatures 303K, 308K, 313K and 318K, and FTIR, UV-vis and 13C NMR spectral studies are presented in this paper. The excess permittivity and excess free energy were fitted with the Redlich-Kister polynomial. The variation of Kirkwood correlation factors, excess permittivity and excess free energy of mixing with the concentration and temperature has been investigated in view of understanding the ordering of dipoles of solute and solvent molecules. The FTIR, UV-vis and 13C NMR spectral analysis reveals the formation of complex between solute and solvent molecules. The parallel alignment of electric dipoles of the complex predicted by dielectric studies is well supported by UV-vis spectral analysis. The structure of the complex molecule present in the clusters has been deduced.

  14. Monitoring the on-line titration of enantiomeric omeprazole employing continuous-flow capillary microcoil 1H NMR spectroscopy.

    PubMed

    Hentschel, Petra; Holtin, Karsten; Steinhauser, Lisa; Albert, Klaus

    2012-12-01

    The titration of the (S)-enantiomer of omeprazole with the (R)-enantiomer in chloroform-d(1) is monitored by continuous-flow capillary microcoil (1)H NMR spectroscopy employing a microcoil with a detection volume of 1.5 µl. The observed changes of the (1)H NMR chemical shifts indicate the formation of a heterochiral (R,S) dimer of omeprazole via its sulfinyl group and the NH group of the benzimidazole ring.

  15. Aqueous-phase quantitative NMR determination of amino acid enantiomer ratio by 13C-NMR using chiral neodymium shift reagent.

    PubMed

    Florini, Nicola; Faglioni, Francesco; Zucchi, Claudia; Caglioti, Luciano; Pályi, Gyula

    2010-05-01

    A neodymium-(S)-PDTA (PDTA = N,N,N',N'-tetrakis[(hydroxycarbonyl)methyl]-1,2-diaminopropane) complex was found exceptionally useful in the quantitative determination of enantiomer ratios of water-soluble natural amino acids by (13)C-NMR. The method is demonstrated on mixtures of L- and D-enantiomers of various amino acids. The interactions of the chiral shift reagent with the amino acid molecules were rationalized by molecular orbital calculations.

  16. Computer-assisted analysis of the structure of regular branched polysaccharides containing 2,3-disubstituted rhamnopyranose and mannopyranose residues on the basis of 13C NMR data.

    PubMed

    Lipkind, G M; Shashkov, A S; Nifant'ev, N E; Kochetkov, N K

    1992-12-31

    A computer-assisted approach to the analysis of the structure of branched polysaccharides that contain 2,3-di-O-glycosylated alpha-rhamnopyranose and alpha-mannopyranose residues is based on evaluation of the 13C NMR spectra, using glycosylation effects and their deviations from additivity (delta delta values) at the branch points. This approach, in combination with monosaccharide and methylation analysis data, has been verified on a series of bacterial polysaccharides of known structure.

  17. Effects of insulin on perfused liver from streptozotocin-diabetic and untreated rats: /sup 13/C NMR assay of pyruvate kinase flux

    SciTech Connect

    Cohen, S.M.

    1987-01-27

    The effects of insulin in vitro on perfused liver from streptozotocin-diabetic rats and their untreated littermates during gluconeogenesis from either (3-/sup 13/C)alanine + ethanol or (2-/sup 13/C)pyruvate + NH/sub 4/Cl + ethanol were studied by /sup 13/C NMR. A /sup 13/C NMR determination of the rate of pyruvate kinase flux under steady-state conditions of active gluconeogenesis was developed; this assay includes a check on the reuse of recycled pyruvate. The preparations studied provided gradations of pyruvate kinase flux within the confines of the assay's requirement of active gluconeogenesis. By this determination, the rate of pyruvate kinase flux was 0.74 +/- 0.04 of the gluconeogenic rate in liver from 24-h-fasted controls; in liver from 12-h fasted controls, relative pyruvate kinase flux increased to 1.0 +/- 0.2. In diabetic liver, this flux was undetectable by the authors NMR method. Insulin's hepatic influence in vitro was greatest in the streptozotocin model of type 1 diabetes: upon treatment of diabetic liver with 7 nM insulin in vitro, a partial reversal of many of the differences noted between diabetic and control liver was demonstrated by /sup 13/C NMR. A major effect of insulin in vitro upon diabetic liver was the induction of a large increase in the rate of pyruvate kinase flux, bringing relative and absolute fluxes up to the levels measured in 24-h-fasted controls. By way of comparison, the effects of ischemia on diabetic liver were studied by /sup 13/C NMR to test whether changes in allosteric effectors under these conditions could also increase pyruvate kinase flux. A large increase in this activity was demonstrated in ischemic diabetic liver.

  18. 13C NMR and XPS characterization of anion adsorbent with quaternary ammonium groups prepared from rice straw, corn stalk and sugarcane bagasse

    NASA Astrophysics Data System (ADS)

    Cao, Wei; Wang, Zhenqian; Zeng, Qingling; Shen, Chunhua

    2016-12-01

    Despite amino groups modified crop straw has been intensively studied as new and low-cost adsorbent for removal of anionic species from water, there is still a lack of clear characterization for amino groups, especially quaternary ammonium groups in the surface of crop straw. In this study, we used 13C NMR and XPS technologies to characterize adsorbents with quaternary ammonium groups prepared from rice straw, corn stalk and sugarcane bagasse. 13C NMR spectra clearly showed the presence of quaternary ammonium groups in lignocelluloses structure of modified crop straw. The increase of nitrogen observed in XPS survey spectra also indicated the existence of quaternary ammonium group in the surface of the adsorbents. The curve fitting of high-resolution XPS N1s and C1s spectra were conducted to probe the composition of nitrogen and carbon contained groups, respectively. The results showed the proportion of quaternary ammonium group significantly increased in the prepared adsorbent's surface that was dominated by methyl/methylene, hydroxyl, quaternary ammonium, ether and carbonyl groups. This study proved that 13C NMR and XPS could be successfully utilized for characterization of quaternary ammonium modified crop straw adsorbents.

  19. Total (1)H NMR assignment of 3β-acetoxypregna-5,16-dien-20-one.

    PubMed

    Becerra-Martinez, Elvia; Ramírez-Gualito, Karla E; Pérez-Hernández, Nury; Joseph-Nathan, Pedro

    2015-12-01

    This work describes the total and unambiguous assignment of the 750 MHz (1)H NMR spectrum of 3β-acetoxypregna-5,16-dien-20-one or 16-DPA (1), the well-known intermediate utilized in the synthesis of biological important commercial steroids. The task was accomplished by extracting the coupling constant values in the overlapped spectrum region by HSQC, and using these values in the (1)H iterative full spin analysis integrated in the PERCH NMR software. Comparison of the experimental vicinal coupling constants of 1 with the values calculated using Altona provides an excellent correlation. The same procedure, when applied to the published data of progesterone (2) and testosterone (3), afforded an acceptable correlation for 2 and a poor correlation for 3. In the last case, this suggested the reassignment of all four vicinal coupling constants for the methylene signals at the C-15 and C-16 positions, demonstrating the utility of this methodology.

  20. Theoretical and experimental investigation of the 1H NMR spectrum of putrescine

    NASA Astrophysics Data System (ADS)

    Allouche, A. R.; Graveron-Demilly, D.; Fauvelle, F.; Aubert-Frécon, M.

    2008-12-01

    Chemical shifts δ and spin-spin coupling constants J have been calculated for the putrescine molecule, a polyamine present in prostate tissue, through a DFT/B3LYP/6-311++G(d,p)/PCM/(GIAO) approach, which has been shown to be accurate in previous work. From δ and J values, calculated for the first time for the isolated and the solvated putrescine, the 1H NMR spectra have been simulated. Comparisons between the calculated and the experimental NMR spectra at 400 MHz show a good agreement and allow to propose reliable values for the NMR spin Hamiltonian parameters of putrescine to be used as good starting values for further quantitation methods of metabolites in prostate tissue.

  1. Composition of beer by 1H NMR spectroscopy: effects of brewing site and date of production.

    PubMed

    Almeida, Cláudia; Duarte, Iola F; Barros, António; Rodrigues, João; Spraul, Manfred; Gil, Ana M

    2006-02-08

    A principal component analysis (PCA) of 1H NMR spectra of beers differing in production site (A, B, C) and date is described, to obtain information about composition variability. First, lactic and pyruvic acids contents were found to vary significantly between production sites, good reproducibility between dates being found for site A but not for sites B and C beers. Second, site B beers were clearly distinguished by the predominance of linear dextrins, while A and C beers were richer in branched dextrins. Carbohydrate reproducibility between dates is poorer for site C with dextrin branching degree varying significantly. Finally, all production sites were successfully distinguished by their contents in adenosine/inosine, uridine, tyrosine/tyrosol, and 2-phenylethanol, reproducibility between dates being again poorer for site C. Interpretation of the above compositional differences is discussed in terms of the biochemistry taking place during brewing, and possible applications of the method in brewing process control are envisaged.

  2. 1H NMR study of the complexation of aromatic drugs with dimethylxanthine derivatives

    NASA Astrophysics Data System (ADS)

    Hernandez Santiago, A. A.; Gonzalez Flores, M.; Rosas Castilla, S. A.; Cervantes Tavera, A. M.; Gutierrez Perez, R.; Khomich, V. V.; Ovchinnikov, D. V.; Parkes, H. G.; Evstigneev, M. P.

    2012-02-01

    With an aim of searching efficient interceptors of aromatic drugs, the self- and hetero-association of dimethylxanthine derivatives with different structures, selected according to Strategy 1 (variation of the position of methyl groups) and Strategy 2 (variation of the length of sbnd (CH2)nsbnd COOH group), with aromatic drug molecules: Ethidium Bromide, Proflavine and Daunomycin, were studied using 1H NMR spectroscopy. It was found that the association proceeds in a form of stacking-type complexation and its energetics is relatively independent on the structure of the dimethylxanthines. However, on average, the dimethylxanthines possess higher hetero-association constant and, hence, higher interceptor ability as compared to the trimethylxanthine, Caffeine, used during the past two decades as a typical interceptor molecule.

  3. Determination of rate constants of N-alkylation of primary amines by 1H NMR spectroscopy.

    PubMed

    Li, Chenghong

    2013-09-05

    Macromolecules containing N-diazeniumdiolates of secondary amines are proposed scaffolds for controlled nitrogen oxide (NO) release medical applications. Preparation of these compounds often involves converting primary amine groups to secondary amine groups through N-alkylation. However, N-alkylation results in not only secondary amines but tertiary amines as well. Only N-diazeniumdiolates of secondary amines are suitable for controlled NO release; therefore, the yield of secondary amines is crucial to the total NO load of the carrier. In this paper, (1)H NMR spectroscopy was used to estimate the rate constants for formation of secondary amine (k1) and tertiary amine (k2) for alkylation reagents such as propylene oxide (PO), methyl acrylate (MA), and acrylonitrile (ACN). At room temperature, the ratio of k2/k1 for the three reactions was found to be around 0.50, 0.026, and 0.0072.

  4. Quantitative 1H NMR: Development and Potential of an Analytical Method – an Update

    PubMed Central

    Pauli, Guido F.; Gödecke, Tanja; Jaki, Birgit U.; Lankin, David C.

    2012-01-01

    Covering the literature from mid-2004 until the end of 2011, this review continues a previous literature overview on quantitative 1H NMR (qHNMR) methodology and its applications in the analysis of natural products (NPs). Among the foremost advantages of qHNMR is its accurate function with external calibration, the lack of any requirement for identical reference materials, a high precision and accuracy when properly validated, and an ability to quantitate multiple analytes simultaneously. As a result of the inclusion of over 170 new references, this updated review summarizes a wealth of detailed experiential evidence and newly developed methodology that supports qHNMR as a valuable and unbiased analytical tool for natural product and other areas of research. PMID:22482996

  5. Cloud point, fluorimetric and 1H NMR studies of ibuprofen-polymer systems

    NASA Astrophysics Data System (ADS)

    Khan, Iqrar Ahmad; Anjum, Kahkashan; Koya, P. Ajmal; Qadeer, Atiytul; Kabir-ud-Din

    2014-01-01

    Influence of six polymers viz. hydroxyethyl cellulose (HEC), hydroxypropyl methyl cellulose (HPMC), polyethylene glycol (PEG), polyvinyl pyrrolidone (PVP), sodium carboxy methyl cellulose (NaCMC) and dextran sulfate (DxS) on solution properties of amphiphilic drug ibuprofen (IBF) has been described in this work. As only HPMC showed the clouding behavior (among the polymers employed herein), its cloud point (CP) was studied in detail in presence of varying amounts of IBF containing different fixed concentrations of inorganic salts (NaCl, NaNO3, Na2SO4, KBr and KNO3). Presence of all these salts had CP reducing effect. By means of steady state fluorescence quenching studies, average aggregation number of IBF aggregates (Nagg) in the presence of varying amounts of the mentioned polymers were evaluated and discussed. 1H NMR studies show that the magnitude of chemical shifts (δ) varies with the nature of the polymer.

  6. (1) H-NMR with Multivariate Analysis for Automobile Lubricant Comparison.

    PubMed

    Kim, Siwon; Yoon, Dahye; Lee, Dong-Kye; Yoon, Changshin; Kim, Suhkmann

    2017-02-23

    Identification of suspected automobile-related lubricants could provide valuable information in forensic cases. We examined that automobile lubricants might exhibit the chemometric characteristics to their individual usages. To compare the degree of clustering in the plots, we co-plotted general industrial oils that were highly dissimilar with automobile lubricants in additive compositions. (1) H-NMR spectroscopy was used with multivariate statistics as a tool for grouping, clustering, and identification of automobile lubricants in laboratory conditions. We analyzed automobile lubricants including automobile engine oils, automobile transmission oils, automobile gear oils, and motorcycle oils. In contrast to the general industrial oils, automobile lubricants showed relatively high tendencies of clustering to their usages. Our pilot study demonstrated that the comparison of known and questioned samples to their usages might be possible in forensic fields.

  7. A subzero 1H NMR relaxation investigation of water dynamics in tomato pericarp.

    PubMed

    Foucat, Loïc; Lahaye, Marc

    2014-09-01

    (1)H NMR relaxation times (T1 and T2) were measured at low field (0.47 T) in pericarp tissues of three tomato genotypes (Ferum, LA0147 and Levovil) at subzero temperature (-20 °C) and two ripening stages (mature green and red). The unfrozen water dynamics was characterised by two T1 and three T2 components. The relaxation time values and their associated relative populations allowed differentiating the ripening stage of only LA0147 and Levovil lines. But the three genotypes were unequivocally discriminated at the red ripe stage. The unfrozen water distribution was discussed in terms of specific interactions, especially with sugars, in relation with their osmoprotectant effects.

  8. Age-Related 1H NMR Characterization of Cerebrospinal Fluid in Newborn and Young Healthy Piglets

    PubMed Central

    Barone, Francesca; Elmi, Alberto; Romagnoli, Noemi; Bacci, Maria Laura

    2016-01-01

    When it comes to neuroscience, pigs represent an important animal model due to their resemblance with humans’ brains for several patterns including anatomy and developmental stages. Cerebrospinal fluid (CSF) is a relatively easy-to-collect specimen that can provide important information about neurological health and function, proving its importance as both a diagnostic and biomedical monitoring tool. Consequently, it would be of high scientific interest and value to obtain more standard physiological information regarding its composition and dynamics for both swine pathology and the refinement of experimental protocols. Recently, proton nuclear magnetic resonance (1H NMR) spectroscopy has been applied in order to analyze the metabolomic profile of this biological fluid, and results showed the technique to be highly reproducible and reliable. The aim of the present study was to investigate in both qualitative and quantitative manner the composition of Cerebrospinal Fluid harvested form healthy newborn (5 days old-P5) and young (30-P30 and 50-P50 days old) piglets using 1H NMR Spectroscopy, and to analyze any possible difference in metabolites concentration between age groups, related to age and Blood-Brain-Barrier maturation. On each of the analyzed samples, 30 molecules could be observed above their limit of quantification, accounting for 95–98% of the total area of the spectra. The concentrations of adenine, tyrosine, leucine, valine, 3-hydroxyvalerate, 3-methyl-2-oxovalerate were found to decrease between P05 and P50, while the concentrations of glutamine, creatinine, methanol, trimethylamine and myo-inositol were found to increase. The P05-P30 comparison was also significant for glutamine, creatinine, adenine, tyrosine, leucine, valine, 3-hydroxyisovalerate, 3-methyl-2-oxovalerate, while for the P30-P50 comparison we found significant differences for glutamine, myo-inositol, leucine and trimethylamine. None of these molecules showed at P30 concentrations

  9. Correlation of lactate and pH in human skeletal muscle after exercise by 1H NMR.

    PubMed

    Pan, J W; Hamm, J R; Hetherington, H P; Rothman, D L; Shulman, R G

    1991-07-01

    We have made in vivo 1H NMR measurements of the time course of pH and lactate in human skeletal muscle after exercise. Spectra were obtained in a 4.7-T 30-cm bore Bruker Biospec spectrometer with a 2.5-cm diameter single surface coil. pH was determined from the shift of the endogenous carnosine H-C2 peak while lactate concentrations were determined by comparison with endogenous total creatine, taken to be 28.5 mM/kg wet wt. Fitting the data shows that the exponential decay of lactate (-0.094 +/- 0.014 min-1. t1/2 = 10.6 min) is slower than that of pH (-0.147 +/- 0.015 min-1, t1/2 = 4.7 min), n = 7 with two different volunteers. These values are significantly different with P less than 0.0005. Relaxation times of lactate and creatine were also measured for lactate quantitation; creatine T1, 1.23 +/- 12 s, T2, 136.2 +/- 26.4 ms (both in resting human muscle); lactate T1 (in postmortem rabbit muscle), 1.0 +/- 11 s and T2, 80 ms (in postexercise human muscle). At the end of intense exercise, the lactate level reached was 25.3 +/- 4.0 mM and the average pH drop was 1.0 pH unit. We discuss the implications of these measurements in conjunction with existing data on other sources of H+ flux, phosphocreatine resynthesis, H+ transport, and contribution of inorganic phosphate to buffering.

  10. Experimental (FT-IR, FT-Raman, UV-Vis, 1H and 13C NMR) and computational (density functional theory) studies on 3-bromophenylboronic acid

    NASA Astrophysics Data System (ADS)

    Karabacak, M.; Kose, E.; Atac, A.; Sas, E. B.; Asiri, A. M.; Kurt, M.

    2014-11-01

    Structurally, boronic acids are trivalent boron-containing organic compounds that possess one alkyl substituent (i.e., C-Br bond) and two hydroxyl groups to fill the remaining valences on the boron atom. We studied 3-bromophenylboronic acid (3BrPBA); a derivative of boronic acid. This study includes the experimental (FT-IR, FT-Raman, 1H and 13C NMR, UV-Vis) techniques and theoretical (DFT-density functional theory) calculations. The experimental data are recorded, FT-IR (4000-400 cm-1) and FT-Raman spectra (3500-10 cm-1) in the solid phase. 1H and 13C NMR spectra are recorded in DMSO solution. UV-Vis spectrum is recorded in the range of 200-400 nm for each solution (in ethanol and water). The theoretical calculations are computed DFT/B3LYP/6-311++G(d,p) basis set. The optimum geometry is also obtained from inside for possible four conformers using according to position of hydrogen atoms after the scan coordinate of these structures. The fundamental vibrations are assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and parallel quantum solutions (PQS) program. 1H and 13C NMR chemical shifts are racked on by using the gauge-invariant atomic orbital (GIAO) method. The time-dependent density functional theory (TD-DFT) is used to find HOMO and LUMO energies, excitation energies, oscillator strengths. The density of state of the studied molecule is investigated as total and partial density of state (TDOS and PDOS) and overlap population density of state (OPDOS or COOP) diagrams have been presented. Besides, frontier molecular orbitals (FMOs), molecular electrostatic potential surface (MEPs) and thermodynamic properties are performed. At the end of this work, the results are ensured beneficial for the literature contribution.

  11. Application of 1H NMR for the characterisation of cocoa beans of different geographical origins and fermentation levels.

    PubMed

    Caligiani, Augusta; Palla, Luigi; Acquotti, Domenico; Marseglia, Angela; Palla, Gerardo

    2014-08-15

    This study reports for the first time the use of (1)H NMR technique combined with chemometrics to study the metabolic profile of cocoa (Theobroma cacao L.) beans of different varieties, origin and fermentation levels. Results of PCA applied to cocoa bean (1)H NMR dataset showed that the main factor influencing the cocoa bean metabolic profile is the fermentation level. In fact well fermented brown beans form a group clearly separated from unfermented, slaty, and underfermented, violet, beans, independently of the variety or geographical origin. Considering only well fermented beans, the metabolic profile obtained by (1)H NMR permitted to discriminate between some classes of samples. The National cocoa of Ecuador, known as Arriba, showed the most peculiar characteristics, while the samples coming from the African region showed some similar traits. The dataset obtained, representative of all the classes of soluble compounds of cocoa, was therefore useful to characterise fermented cocoa beans as a function of their origin and fermentation level.

  12. Fatty acids profile of Sacha Inchi oil and blends by 1H NMR and GC-FID.

    PubMed

    Vicente, Juarez; de Carvalho, Mario Geraldo; Garcia-Rojas, Edwin E

    2015-08-15

    This study aimed at the characterization of blends of Sacha Inchi oil (SIO) with different ratios of SO (soybean oil) and CO (corn oil) by nuclear magnetic resonance ((1)H NMR), compared with the data obtained by gas chromatography with a flame ionization detector (GC-FID). The (1)H NMR and GC-FID data from different ratios of SIO were adjusted by a second order polynomial equation. The two techniques were highly correlated (R(2) values ranged from 0.995 to 0.999), revealing that (1)H NMR is an efficient methodology for the quantification of omega-3 fatty acids in oils rich in omega-6 fatty acids or vice versa such as SO and CO and, on the other hand, can be used to quantify ω-6 in oils rich in ω-3, such as SIO.

  13. Dipolar cross-relaxation modulates signal amplitudes in the 1H NMR spectrum of hyperpolarized [ 13C]formate

    NASA Astrophysics Data System (ADS)

    Merritt, Matthew E.; Harrison, Crystal; Mander, William; Malloy, Craig R.; Dean Sherry, A.

    2007-12-01

    The asymmetry in the doublet of a spin coupled to hyperpolarized 13C has been used previously to measure the initial polarization of 13C. We tested the hypothesis that a single observation of the 1H NMR spectrum of hyperpolarized 13C formate monitors 13C polarization. Depending on the microwave frequency during the polarization process, in-phase or out-of-phase doublets were observed in the 1H NMR spectrum. Even in this simple two-spin system, 13C polarization was not reflected in the relative area of the JCH doublet components due to strong heteronuclear cross-relaxation. The Solomon equations were used to model the proton signal as a function of time after polarization and to estimate 13C polarization from the 1H NMR spectra.

  14. 1H NMR determination of beta-N-methylamino-L-alanine (L-BMAA) in environmental and biological samples.

    PubMed

    Moura, Sidnei; Ultramari, Mariah de Almeida; de Paula, Daniela Mendes Louzada; Yonamine, Mauricio; Pinto, Ernani

    2009-04-01

    A nuclear magnetic resonance (1H NMR) method for the determination of beta-N-methylamino-L-alanine (L-BMAA) in environmental aqueous samples was developed and validated. L-BMAA is a neurotoxic modified amino acid that can be produced by cyanobacteria in aqueous environments. This toxin was extracted from samples by means of solid-phase extraction (SPE) and identified and quantified by 1H NMR without further derivatization steps. The lower limit of quantification (LLOQ) was 5 microg/mL. Good inter and intra-assay precision was also observed (relative standard deviation <8.5%) with the use of 4-nitro-DL-phenylalanine as an internal standard (IS). This method of 1H NMR analysis is not time consuming and can be readily utilized to monitor L-BMAA and confirm its presence in environmental and biological samples.

  15. Metabolomic by 1H NMR spectroscopy differentiates "Fiano di Avellino" white wines obtained with different yeast strains.

    PubMed

    Mazzei, Pierluigi; Spaccini, Riccardo; Francesca, Nicola; Moschetti, Giancarlo; Piccolo, Alessandro

    2013-11-13

    We employed (1)H NMR spectroscopy to examine the molecular profile of a white "Fiano di Avellino" wine obtained through fermentation by either a commercial or a selected autochthonous Saccharomyces cerevisiae yeast starter. The latter was isolated from the same grape variety used in the wine-making process in order to strengthen the relationship between wine molecular quality and its geographical origin. (1)H NMR spectra, where water and ethanol signals were suppressed by a presaturated T1-edited NMR pulse sequence, allowed for definition of the metabolic content of the two differently treated wines. Elaboration of NMR spectral data by multivariate statistical analyses showed that the two different yeasts led to significant diversity in the wine metabolomes. Our results indicate that metabolomics by (1)H NMR spectroscopy combined with multivariate statistical analysis enables wine differentiation as a function of yeast species and other wine-making factors, thereby contributing to objectively relate wine quality to the terroir.

  16. Synthesis and complete assignment of the 1H and 13C NMR spectra of 6-substituted and 2,6-disubstituted pyridazin-3(2H)-ones.

    PubMed

    Besada, Pedro; Costas, Tamara; Vila, Noemi; Chessa, Carla; Terán, Carmen

    2011-07-01

    Several pyridazin-3(2H)-one derivatives were synthesized starting from alkyl furans using oxidation with singlet oxygen to give 4-methoxy or 4-hydroxybutenolides, key intermediates of the synthetic strategy followed. For all pyridazinones reported, a complete assignment of the (1)H and (13)C NMR spectra using one- and two-dimensional NMR spectroscopic methods, which included NOE, DEPT, COSY, HSQC and HMBC experiments, was accomplished. Correlations between the chemical shifts of the heterocyclic ring atoms and substituents at N-2 and C-6 were analyzed.

  17. 1H and 13C NMR Chemical Shift Assignments and Conformational Analysis for the Two Diastereomers of the Vitamin K Epoxide Reductase Inhibitor Brodifacoum

    SciTech Connect

    Cort, John R.; Cho, Herman M.

    2009-10-01

    Proton and 13C NMR chemical shift assignments and 1H-1H scalar couplings for the two diastereomers of the vitamin K epoxide reductase (VKOR) inhibitor brodifacoum have been determined from acetone solutions containing both diastereomers. Data were obtained from homo- and heteronuclear correlation spectra acquired at 1H frequencies of 750 and 900 MHz over a 268-303 K temperature range. Conformations inferred from scalar coupling and 1-D NOE measurements exhibit large differences between the diastereomers. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  18. (1)H NMR-based metabolomic approach for understanding the fermentation behaviors of wine yeast strains.

    PubMed

    Son, Hong-Seok; Hwang, Geum-Sook; Kim, Ki Myong; Kim, Eun-Young; van den Berg, Frans; Park, Won-Mok; Lee, Cherl-Ho; Hong, Young-Shick

    2009-02-01

    (1)H NMR spectroscopy coupled with multivariate statistical analysis was used for the first time to investigate metabolic changes in musts during alcoholic fermentation and wines during aging. Three Saccharomyces cerevisiae yeast strains (RC-212, KIV-1116, and KUBY-501) were also evaluated for their impacts on the metabolic changes in must and wine. Pattern recognition (PR) methods, including PCA, PLS-DA, and OPLS-DA scores plots, showed clear differences for metabolites among musts or wines for each fermentation stage up to 6 months. Metabolites responsible for the differentiation were identified as valine, 2,3-butanediol (2,3-BD), pyruvate, succinate, proline, citrate, glycerol, malate, tartarate, glucose, N-methylnicotinic acid (NMNA), and polyphenol compounds. PCA scores plots showed continuous movements away from days 1 to 8 in all musts for all yeast strains, indicating continuous and active fermentation. During alcoholic fermentation, the highest levels of 2,3-BD, succinate, and glycerol were found in musts with the KIV-1116 strain, which showed the fastest fermentation or highest fermentative activity of the three strains, whereas the KUBY-501 strain showed the slowest fermentative activity. This study highlights the applicability of NMR-based metabolomics for monitoring wine fermentation and evaluating the fermentative characteristics of yeast strains.

  19. 1H NMR relaxation of water: a probe for surfactant adsorption on kaolin.

    PubMed

    Totland, Christian; Lewis, Rhiannon T; Nerdal, Willy

    2011-11-01

    In this study, (1)H NMR is used to investigate properties of sodium dodecyl sulfate (SDS), tetradecyl trimethyl ammonium bromide (TTAB), and dodecyl trimethyl ammonium bromide (DTAB) adsorbed on kaolin by NMR T(1) and T(2) measurements of the water proton resonance. The results show that adsorbed surfactants form a barrier between sample water and the paramagnetic species present on the clay surface, thus significantly increasing the proton T(1) values of water. This effect is attributed to the amount of adsorbed surfactants and the arrangement of the surfactant aggregates. The total surface area covered by the cationic (DTAB and TTAB) and anionic (SDS) surfactants could be estimated from the water T(1) data and found to correspond to the fractions of negatively and positively charged surface area, respectively. For selected samples, the amount of paramagnetic species on the clay surface was reduced by treatment with hydrofluoric (HF) acid. For these samples, T(1) and T(2) measurements were taken in the temperature range 278-338 K, revealing detailed information on molecular mobility and nuclear exchange for the sample water that is related to surfactant behavior both on the surface and in the aqueous phase.

  20. 1H-NMR metabolite profiles of different strains of Plasmodium falciparum

    PubMed Central

    Teng, Rongwei; Lehane, Adele M.; Winterberg, Markus; Shafik, Sarah H.; Summers, Robert L.; Martin, Rowena E.; van Schalkwyk, Donelly A.; Junankar, Pauline R.; Kirk, Kiaran

    2014-01-01

    Although efforts to understand the basis for inter-strain phenotypic variation in the most virulent malaria species, Plasmodium falciparum, have benefited from advances in genomic technologies, there have to date been few metabolomic studies of this parasite. Using 1H-NMR spectroscopy, we have compared the metabolite profiles of red blood cells infected with different P. falciparum strains. These included both chloroquine-sensitive and chloroquine-resistant strains, as well as transfectant lines engineered to express different isoforms of the chloroquine-resistance-conferring pfcrt (P. falciparum chloroquine resistance transporter). Our analyses revealed strain-specific differences in a range of metabolites. There was marked variation in the levels of the membrane precursors choline and phosphocholine, with some strains having >30-fold higher choline levels and >5-fold higher phosphocholine levels than others. Chloroquine-resistant strains showed elevated levels of a number of amino acids relative to chloroquine-sensitive strains, including an approximately 2-fold increase in aspartate levels. The elevation in amino acid levels was attributable to mutations in pfcrt. Pfcrt-linked differences in amino acid abundance were confirmed using alternate extraction and detection (HPLC) methods. Mutations acquired to withstand chloroquine exposure therefore give rise to significant biochemical alterations in the parasite. PMID:25405893

  1. Spatially localized sup 1 H NMR spectra of metabolites in the human brain

    SciTech Connect

    Hanstock, C.C. ); Rothman, D.L.; Jue, T.; Shulman, R.G. ); Prichard, J.W. )

    1988-03-01

    Using a surface coil, the authors have obtained {sup 1}H NMR spectra from metabolites in the human brain. Localization was achieved by combining depth pulses with image-selected in vivo spectroscopy magnetic field gradient methods. {sup 1}H spectra in which total creatine (3.03 ppm) has a signal/noise ratio of 95:1 were obtained in 4 min from 14 ml of brain. A resonance at 2.02 ppm consisting predominantly of N-acetylaspartate was measured relative to the creatine peak in gray and white matter, and the ratio was lower in the white matter. The spin-spin relaxation times of N-acetylaspartate and creatine were measured in white and gray matter and while creatine relaxation times were the same in both, the N-acetylaspartate relaxation time was longer in white matter. Lactate was detected in the normoxic brain and the average of three measurements was {approx}0.5 mM from comparison with the creatine plus phosphocreatine peak, which was assumed to be 10.5 mM.

  2. Towards high resolution ^1H NMR spectra of tannin colloidal aggregates

    NASA Astrophysics Data System (ADS)

    Mirabel, M.; Glories, Y.; Pianet, I.; Dufourc, E. J.

    1999-10-01

    The time dependent colloidal formation of tannins in hydro-alcoholic medium has been studied by 1H-NMR. Line broadening observed with time can be cancelled by making use of magic angle sample spinning (MASS) thus yielding sharp lines that allow structural studies. We used as an example catechin, a constitutive monomer of Bordeaux young red wine tannins. Chemical shift variations of polyphenol protons allow monitoring the time course of aggregation. La formation de tanins colloïdaux au cours du temps, en milieu hydroalcoolique, a été suivie par RMN-^1H. Un élargissement marqué des résonances est observé et peut être supprimé par la rotation de l'échantillon à l'angle magique ce qui ouvre tout un champ d'études structurales sur ces composés colloïdaux. L'exemple proposé est celui de la catéchine, monomère constitutif de tannins présents en grande quantité dans les vins rouges jeunes de Bordeaux. Des variations du déplacement chimique de certains protons polyphénoliques permettent de suivre l'évolution temporelle de l'agrégation.

  3. Quantification of acesulfame potassium in processed foods by quantitative 1H NMR.

    PubMed

    Ohtsuki, Takashi; Sato, Kyoko; Abe, Yutaka; Sugimoto, Naoki; Akiyama, Hiroshi

    2015-01-01

    Acesulfame potassium (AceK), a high-intensity and non-caloric artificial sweetener, is used in various processed foods as a food additive. In this study, we established and validated a method for determining the AceK content in various processed foods by solvent extraction and quantitative (1)H NMR, using a certified reference material as the internal standard. In the recovery test, the proposed method gave satisfactory recoveries (88.4-99.6%) and repeatabilities (0.6-5.6%) for various processed foods. The limit of quantification was confirmed as 0.13 g kg(-1), which was sufficiently low for the purposes of monitoring AceK levels. In the analysis of commercially processed foods containing AceK, all AceK contents determined by the proposed method were in good agreement with those obtained by a conventional method based on dialysis and HPLC. Moreover, this method can achieve rapid quantification and yields analytical data with traceability to the International System of Units (SI) without the need for an authentic analyte standard. Therefore, the proposed method is a useful and practical tool for the determination of AceK in processed foods.

  4. 1H NMR-based metabolic profiling for evaluating poppy seed rancidity and brewing.

    PubMed

    Jawień, Ewa; Ząbek, Adam; Deja, Stanisław; Łukaszewicz, Marcin; Młynarz, Piotr

    2015-12-01

    Poppy seeds are widely used in household and commercial confectionery. The aim of this study was to demonstrate the application of metabolic profiling for industrial monitoring of the molecular changes which occur during minced poppy seed rancidity and brewing processes performed on raw seeds. Both forms of poppy seeds were obtained from a confectionery company. Proton nuclear magnetic resonance (1H NMR) was applied as the analytical method of choice together with multivariate statistical data analysis. Metabolic fingerprinting was applied as a bioprocess control tool to monitor rancidity with the trajectory of change and brewing progressions. Low molecular weight compounds were found to be statistically significant biomarkers of these bioprocesses. Changes in concentrations of chemical compounds were explained relative to the biochemical processes and external conditions. The obtained results provide valuable and comprehensive information to gain a better understanding of the biology of rancidity and brewing processes, while demonstrating the potential for applying NMR spectroscopy combined with multivariate data analysis tools for quality control in food industries involved in the processing of oilseeds. This precious and versatile information gives a better understanding of the biology of these processes.

  5. Combined Analysis of Stable Isotope, (1)H NMR, and Fatty Acid To Verify Sesame Oil Authenticity.

    PubMed

    Kim, Jeongeun; Jin, Gyungsu; Lee, Yunhee; Chun, Hyang Sook; Ahn, Sangdoo; Kim, Byung Hee

    2015-10-14

    The aim of this study was to verify the authenticity of sesame oils using combined analysis of stable isotope ratio, (1)H NMR spectroscopy, and fatty acid profiles of the oils. Analytical data were obtained from 35 samples of authentic sesame oils and 29 samples of adulterated sesame oils currently distributed in Korea. The orthogonal projection to latent structure discriminant analysis technique was used to select variables that most effectively verify the sesame oil authenticity. The variables include δ(13)C value, integration values of NMR peaks that signify the CH3 of n-3 fatty acids, CH2 between two C═C, protons from sesamin/sesamolin, and 18:1n-9, 18:3n-3, 18:2t, and 18:3t content values. The authenticity of 65 of 70 blind samples was correctly verified by applying the range of the eight variables found in the authentic sesame oil samples, suggesting that triple analysis is a useful approach to verify sesame oil authenticity.

  6. Resolution Improvements in in Vivo1H NMR Spectra with Increased Magnetic Field Strength

    NASA Astrophysics Data System (ADS)

    Gruetter, Rolf; Weisdorf, Sally A.; Rajanayagan, Vasantham; Terpstra, Melissa; Merkle, Hellmut; Truwit, Charles L.; Garwood, Michael; Nyberg, Scott L.; Ugurbil, Kâmil

    1998-11-01

    The measurement of cerebral metabolites using highly homologous localization techniques and similar shimming methods was performed in the human brain at 1.5 and 4 T as well as in the dog and rat brain at 9.4 T. In rat brain, improved resolution was achieved by shimming all first- and second-order shim coils using a fully adiabatic FASTMAP sequence. The spectra showed a clear improvement in spectral resolution for all metabolite resonances with increased field strength. Changes in cerebral glutamine content were clearly observed at 4 T compared to 1.5 T in patients with hepatic encephalopathy. At 9.4 T, glutamine H4 at 2.46 ppm was fully resolved from glutamate H4 at 2.37 ppm, as was the potential resonance from γ-amino-butyric acid at 2.30 ppm and N-acetyl-aspartyl-glutamate at 2.05 ppm. Singlet linewidths were found to be as low as 6 Hz (0.015 ppm) at 9.4 T, indicating a substantial decrease in ppm linewidth with field strength. Furthermore, the methylene peak of creatine was partially resolved from phosphocreatine, indicating a close to 1:1 relationship in gray matter. We conclude that increasing the magnetic field strength increases spectral resolution also for1H NMR, which can lead to more than linear sensitivity gains.

  7. (1)H NMR spectroscopy for profiling complex carbohydrate mixtures in non-fractionated beer.

    PubMed

    Petersen, Bent O; Nilsson, Mathias; Bøjstrup, Marie; Hindsgaul, Ole; Meier, Sebastian

    2014-05-01

    A plethora of biological and biotechnological processes involve the enzymatic remodelling of carbohydrates in complex mixtures whose compositions affect both the processes and products. In the current study, we employed high-resolution (1)H NMR spectroscopy for the analysis of cereal-derived carbohydrate mixtures as exemplified on six beer samples of different styles. Structural assignments of more than 50 carbohydrate moieties were obtained using (1)H1-(1)H2 groups as structural reporters. Spectroscopically resolved carbohydrates include more than ''20 different'' small carbohydrates with more than 38 isomeric forms in addition to cereal polysaccharide fragments with suspected organoleptic and prebiotic function. Structural motifs at the cleavage sites of starch, β-glucan and arabinoxylan fragments were identified, showing different extent and specificity of enzymatic polysaccharide cleavage during the production of different beer samples. Diffusion ordered spectroscopy supplied independent size information for the characterisation and identification of polysaccharide fragments, indicating the presence especially of high molecular weight arabinoxylan fragments in the final beer.

  8. Relativistic force field: parametric computations of proton-proton coupling constants in (1)H NMR spectra.

    PubMed

    Kutateladze, Andrei G; Mukhina, Olga A

    2014-09-05

    Spin-spin coupling constants in (1)H NMR carry a wealth of structural information and offer a powerful tool for deciphering molecular structures. However, accurate ab initio or DFT calculations of spin-spin coupling constants have been very challenging and expensive. Scaling of (easy) Fermi contacts, fc, especially in the context of recent findings by Bally and Rablen (Bally, T.; Rablen, P. R. J. Org. Chem. 2011, 76, 4818), offers a framework for achieving practical evaluation of spin-spin coupling constants. We report a faster and more precise parametrization approach utilizing a new basis set for hydrogen atoms optimized in conjunction with (i) inexpensive B3LYP/6-31G(d) molecular geometries, (ii) inexpensive 4-31G basis set for carbon atoms in fc calculations, and (iii) individual parametrization for different atom types/hybridizations, not unlike a force field in molecular mechanics, but designed for the fc's. With the training set of 608 experimental constants we achieved rmsd <0.19 Hz. The methodology performs very well as we illustrate with a set of complex organic natural products, including strychnine (rmsd 0.19 Hz), morphine (rmsd 0.24 Hz), etc. This precision is achieved with much shorter computational times: accurate spin-spin coupling constants for the two conformers of strychnine were computed in parallel on two 16-core nodes of a Linux cluster within 10 min.

  9. Polypharmacotherapy in rheumatology: 1H NMR analysis of binding of phenylbutazone and methotrexate to serum albumin

    NASA Astrophysics Data System (ADS)

    Maciążek-Jurczyk, M.; Sułkowska, A.; Równicka-Zubik, J.; Bojko, B.; Szkudlarek-Haśnik, A.; Knopik, M.; Sułkowski, W. W.

    2011-05-01

    The influence of phenylbutazone (Phe) and methotrexate (MTX) on binding of MTX and Phe to human (HSA) and bovine (BSA) serum albumin in the low-affinity binding sites is investigated. The strength and kind of interactions between serum albumin (SA) and drugs used in combination therapy were found using 1H NMR spectroscopy. A stoichiometric molar ratios for Phe-SA and MTX-SA complexes are 36:1 and 31:1, respectively. It appeared these molar ratios are higher for the ternary systems than it were in the binary ones. The presence of the additional drug (MTX or Phe) causes the increase of an affinity of albumin towards Phe and MTX. It was found that the aliphatic groups of MTX are more resistant to the influence of Phe on the MTX-SA complex than the aromatic rings. The results showed the important impact of another drug (MTX or Phe) on the affinity of SA towards Phe and MTX in the low-affinity binding sites. This work is a subsequent part of the spectroscopic study on Phe-MTX-SA interactions (Maciążek-Jurczyk, 2009 [1]).

  10. Automatic 1H-NMR Screening of Fatty Acid Composition in Edible Oils

    PubMed Central

    Castejón, David; Fricke, Pascal; Cambero, María Isabel; Herrera, Antonio

    2016-01-01

    In this work, we introduce an NMR-based screening method for the fatty acid composition analysis of edible oils. We describe the evaluation and optimization needed for the automated analysis of vegetable oils by low-field NMR to obtain the fatty acid composition (FAC). To achieve this, two scripts, which automatically analyze and interpret the spectral data, were developed. The objective of this work was to drive forward the automated analysis of the FAC by NMR. Due to the fact that this protocol can be carried out at low field and that the complete process from sample preparation to printing the report only takes about 3 min, this approach is promising to become a fundamental technique for high-throughput screening. To demonstrate the applicability of this method, the fatty acid composition of extra virgin olive oils from various Spanish olive varieties (arbequina, cornicabra, hojiblanca, manzanilla, and picual) was determined by 1H-NMR spectroscopy according to this protocol. PMID:26891323

  11. Enantioseparation of cetirizine by chromatographic methods and discrimination by 1H-NMR.

    PubMed

    Taha, Elham A; Salama, Nahla N; Wang, Shudong

    2009-03-01

    Cetirizine is an antihistaminic drug used to prevent and treat allergic conditions. It is currently marketed as a racemate. The H1-antagonist activity of cetirizine is primarily due to (R)-levocetirizine. This has led to the introduction of (R)-levocetirizine into clinical practice, and the chiral switching is expected to be more selective and safer. The present work represents three methods for the analysis and chiral discrimination of cetirizine. The first method was based on the enantioseparation of cetirizine on silica gel TLC plates using different chiral selectors as mobile phase additives. The mobile phase enabling successful resolution was acetonitrile-water 17: 3, (v/v) containing 1 mM of chiral selector, namely hydroxypropyl-beta-cyclodextrin, chondroitin sulphate or vancomycin hydrochloride. The second method was a validated high performance liquid chromatography (HPLC), based on stereoselective separation of cetirizine and quantitative determination of its eutomer (R)-levocetirizine on a monolithic C18 column using hydroxypropyl-beta-cyclodextrin as a chiral mobile phase additive. The resolved peaks of (R)-levocetirizine and (S)-dextrocetirizine were confirmed by further mass spectrometry. The third method used a (1)H-NMR technique to characterize cetirizine and (R)-levocetirizine. These methods are selective and accurate, and can be easily applied for chiral discrimination and determination of cetirizine in drug substance and drug product in quality control laboratory. Moreover, chiral purity testing of (R)-levocetirizine can also be monitored by the chromatographic methods.

  12. Secondary structure determination of human. beta. -endorphin by /sup 1/H NMR spectroscopy

    SciTech Connect

    Lichtarge, O.; Jardetzky, O.; Li, C.H.

    1987-09-08

    The /sup 1/H NMR spectra of human ..beta..-endorphin indicate that the peptide exists in random-coil form in aqueous solution but becomes helical in mixed solvent. Thermal denaturation NMR experiments show that in water there is no transition between 24 and 75/sup 0/C, while a slow noncooperative thermal unfolding is observed in a 60% methanol-40% water mixed solvent in the same temperature range. These findings are consistent with circular dichroism studies by other workers concluding that ..beta..-endorphin is a random coil in water but that it forms 50% ..cap alpha..-helix or more in mixed solvents. The peptide in the mixed water-methanol solvent was further studied by correlated spectroscopy (COSY) and nuclear Overhauser effect spectroscopy (NOESY) experiments. These allow a complete set of assignments to be made and establish two distinct stretches over which the solvent induces formation of ..cap alpha..-helices: the first occurs between Tyr-1 and Thr-12 and the second between Leu-14 and extending to Lys-28. There is evidence that the latter is capped by a turn occurring between Lys-28 and Glu-31. These helices form at the enkephalin receptor binding site, which is at the amino terminus, and at the morphine receptor binding site, located at the carboxyl terminus. The findings suggest that these two receptors may specifically recognize ..cap alpha..-helices.

  13. Arrangement and mobility of water in vermiculite hydrates followed by 1H NMR spectroscopy.

    PubMed

    Sanz, J; Herrero, C P; Serratosa, J M

    2006-04-20

    The arrangement of water molecules in one- and two-layer hydrates of high-charged vermiculites, saturated with alkaline (Li(+), Na(+)) and alkali-earth (Mg(2+), Ca(2+), Ba(2+)) cations, has been analyzed with (1)H NMR spectroscopy. Two different orientations for water molecules have been found, depending on the hydration state and the sites occupied by interlayer cations. As the amount of water increases, hydrogen bond interactions between water molecules increase at expenses of water-silicate interactions. This interaction favors water mobility in vermiculites. A comparison of the temperature dependence of relaxation times T(1) and T(2) for one and two-layer hydrates of Na-vermiculite shows that the rotations of water molecules around C(2)-axes and that of cation hydration shells around the c-axis is favored in the two-layer hydrate. In both hydrates, the anisotropic diffusion of water takes place at room temperature, preserving the orientation of water molecules relative to the silicate layers. Information obtained by NMR spectroscopy is compatible with that deduced by infrared spectroscopy and with structural studies carried out with X-ray and neutron diffraction techniques on single-crystals of vermiculite.

  14. Rapid determination of coenzyme Q10 in food supplements using 1H NMR spectroscopy.

    PubMed

    Monakhova, Yulia B; Ruge, Ingrid; Kuballa, Thomas; Lerch, Christiane; Lachenmeier, Dirk W

    2013-01-01

    A methodology utilizing 1H NMR spectroscopy has been developed to measure the concentration of coenzyme Q10 (CoQ10) in dietary supplements. For sample preparation, a very simple dilution with deuterated chloroform and addition of internal standard is sufficient. CoQ10 produces a distinct peak of the CH groups in the isoprene side chain of the molecule in the δ 5.15 - 5.05 ppm range, where it can be distinguished from other matrix compounds. The method was shown to be of adequate sensitivity with a limit of detection (LOD) of 7.8 mg/L, to control the CoQ10 content in the majority of the products. The precision expressed as relative standard deviation was around 5 %; linearity was observed from 14 to 2000 mg/L (R = 0.99). The developed methodology was applied for the analysis of 21 food supplements (capsules, tablets, and liquid products). On the basis of the labeled amounts, only two products contained substantially lower concentrations of CoQ10 (57 % and 51 %). All other concentrations varied between 83 % and 190 % with respect to labeling. The developed NMR method may be used by quality assurance laboratories for routine control of CoQ10 products.

  15. 1H NMR Spectroscopy and MVA Analysis of Diplodus sargus Eating the Exotic Pest Caulerpa cylindracea

    PubMed Central

    De Pascali, Sandra A.; Del Coco, Laura; Felline, Serena; Mollo, Ernesto; Terlizzi, Antonio; Fanizzi, Francesco P.

    2015-01-01

    The green alga Caulerpa cylindracea is a non-autochthonous and invasive species that is severely affecting the native communities in the Mediterranean Sea. Recent researches show that the native edible fish Diplodus sargus actively feeds on this alga and cellular and physiological alterations have been related to the novel alimentary habits. The complex effects of such a trophic exposure to the invasive pest are still poorly understood. Here we report on the metabolic profiles of plasma from D. sargus individuals exposed to C. cylindracea along the southern Italian coast, using 1H NMR spectroscopy and multivariate analysis (Principal Component Analysis, PCA, Orthogonal Partial Least Square, PLS, and Orthogonal Partial Least Square Discriminant Analysis, OPLS-DA). Fish were sampled in two seasonal periods from three different locations, each characterized by a different degree of algal abundance. The levels of the algal bisindole alkaloid caulerpin, which is accumulated in the fish tissues, was used as an indicator of the trophic exposure to the seaweed and related to the plasma metabolic profiles. The profiles appeared clearly influenced by the sampling period beside the content of caulerpin, while the analyses also supported a moderate alteration of lipid and choline metabolism related to the Caulerpa-based diet. PMID:26058009

  16. 1H-NMR characterization of poly(ethylene glycol) and polydimethylsiloxane copolymer

    NASA Astrophysics Data System (ADS)

    Zainuddin, Ain Athirah; Othaman, Rizafizah; Noor, Wan Syaidatul Aqma Wan Mohd; Anuar, Farah Hannan

    2016-11-01

    This paper describes the synthesis and characterization of poly(ethylene glycol) (PEG) and polydimethylsiloxane (PDMS) copolymers. The copolymers were synthesized by reacting hydroxyl group (-OH) of poly(ethylene glycol) (PEG) and polydimetylsiloxane (PDMS) with isocyanate group (R-N=C=O) of 1,6-hexamethylene diisocyanate (HMDI). The reaction was carried out at room temperature. The copolymers were synthesized in three different compositions which differ in molar ratios of PEG to PDMS. The ratios (PEG:PDMS) used were 2:6. 3:5 and 4:4. The formation of the copolymers was characterized by 1H Nuclear Magnetic Resonance (1H-NMR) for structural determination. The presence of proton signal at 4.80 ppm which belongs to the proton of urethane group indicates the formation of urethane links. The formation of urethane links showed that two homopolymers were linked together by HMDI to form longer copolymer chains. It is worth to note that the sequence of PEG and PDMS along the copolymer chain is random.

  17. 1H NMR spectra of humic and fulvic acids and their peracetic oxidation products

    NASA Astrophysics Data System (ADS)

    Ruggiero, P.; Interesse, F. S.; Cassidei, L.; Sciacovelli, O.

    1980-04-01

    1H NMR spectra of humic (HA) and fulvic (FA) acids and their oxidative degradation products are reported. The HA shows the presence of -( CH2) n - CH3 ( n > 6) chemical fragments belonging to n-alkanes and/or n-fatty acids physically adsorbed onto the macromolecule structure. These fragments are absent in the FA fraction. Both humic fractions reveal the presence of similar amounts of aromatic protons which partly undergo exchange phenomena. The importance of this experimental observation is discussed. Oxidative degradation seems to cause partial cleavage of aromatic rings, more pronounced in the FA than in the HA. The degraded FA shows a higher total acidity and a higher phenolic OH content than the degraded HA. Both degraded fractions display some sharp singlet signals at 1.9 and 3.9 ppm arising from protons belonging to repetitive chemical fragments probably formed during the oxidation reaction. Tentative assignments of these signals are given. A general analysis of the HA and FA degraded spectra seems to indicate that the chemical fragments which undergo peracetic oxidation are substantially similar. The extent of oxidation of the two humic fractions is different. The HA degradation products reveal the presence of oligomeric structures, whereas the degraded FA appears less resistant to the oxidizing agent.

  18. The conformational stability, solvation and the assignments of the experimental infrared, Raman, (1)H and (13)C NMR spectra of the local anesthetic drug lidocaine.

    PubMed

    Badawi, Hassan M; Förner, Wolfgang; Ali, Shaikh A

    2015-05-05

    The structure, vibrational and (1)H and (13)C NMR spectra of the local anesthetic drug lidocaine were investigated by the B3LYP/6-311G(∗∗) calculations. The molecule was predicted to have the non-planar cis (NCCN∼0°) structures being about 2-6kcal/mol lower in energy than the corresponding trans (NCCN∼180°) forms. The calculated NCCN (9.6°) and CNCC (-132.2°) torsional angles were in a good qualitative agreement with the reported X-ray angles (3.1 and 13.0°, -102.67 and -77.9°, respectively, for H-bonded dimers). The Gibbs energy of solution of lidocaine in formamide, water, dimethylsulfoxide, acetonitrile, methanol, ethanol and chloroform solutions was estimated at the B3LYP level. The predicted affinity of lidocaine toward the alcohols, acetonitrile and chloroform solutions was in excellent agreement with the reported experimental solubility of the drug in organic solvents. The analysis of the observed vibrational spectra is consistent with the presence of lidocaine in only one conformation at room temperature. The (1)H and (13)C NMR spectra of lidocaine were interpreted by experimental and DFT calculated chemical shifts of the drug. The RMSD between experimental and theoretical (1)H and (13)C chemical shifts for lidocaine is 0.47 and 8.26ppm, respectively.

  19. The conformational stability, solvation and the assignments of the experimental infrared, Raman, 1H and 13C NMR spectra of the local anesthetic drug lidocaine

    NASA Astrophysics Data System (ADS)

    Badawi, Hassan M.; Förner, Wolfgang; Ali, Shaikh A.

    2015-05-01

    The structure, vibrational and 1H and 13C NMR spectra of the local anesthetic drug lidocaine were investigated by the B3LYP/6-311G∗∗ calculations. The molecule was predicted to have the non-planar cis (NCCN ∼ 0°) structures being about 2-6 kcal/mol lower in energy than the corresponding trans (NCCN ∼ 180°) forms. The calculated NCCN (9.6°) and CNCC (-132.2°) torsional angles were in a good qualitative agreement with the reported X-ray angles (3.1 and 13.0°, -102.67 and -77.9°, respectively, for H-bonded dimers). The Gibbs energy of solution of lidocaine in formamide, water, dimethylsulfoxide, acetonitrile, methanol, ethanol and chloroform solutions was estimated at the B3LYP level. The predicted affinity of lidocaine toward the alcohols, acetonitrile and chloroform solutions was in excellent agreement with the reported experimental solubility of the drug in organic solvents. The analysis of the observed vibrational spectra is consistent with the presence of lidocaine in only one conformation at room temperature. The 1H and 13C NMR spectra of lidocaine were interpreted by experimental and DFT calculated chemical shifts of the drug. The RMSD between experimental and theoretical 1H and 13C chemical shifts for lidocaine is 0.47 and 8.26 ppm, respectively.

  20. Hydrogen bond geometries and proton tautomerism of homoconjugated anions of carboxylic acids studied via H/D isotope effects on 13C NMR chemical shifts.

    PubMed

    Guo, Jing; Tolstoy, Peter M; Koeppe, Benjamin; Golubev, Nikolai S; Denisov, Gleb S; Smirnov, Sergei N; Limbach, Hans-Heinrich

    2012-11-26

    Ten formally symmetric anionic OHO hydrogen bonded complexes, modeling Asp/Glu amino acid side chain interactions in nonaqueous environment (CDF(3)/CDF(2)Cl solution, 200-110 K) have been studied by (1)H, (2)H, and (13)C NMR spectroscopy, i.e. intermolecularly H-bonded homoconjugated anions of acetic, chloroacetic, dichloroacetic, trifluoroacetic, trimethylacetic, and isobutyric acids, and intramolecularly H-bonded hydrogen succinate, hydrogen rac-dimethylsuccinate, hydrogen maleate, and hydrogen phthalate. In particular, primary H/D isotope effects on the hydrogen bond proton signals as well as secondary H/D isotope effects on the (13)C signals of the carboxylic groups are reported and analyzed. We demonstrate that in most of the studied systems there is a degenerate proton tautomerism between O-H···O(-) and O(-)···H-O structures which is fast in the NMR time scale. The stronger is the proton donating ability of the acid, the shorter and more symmetric are the H-bonds in each tautomer of the homoconjugate. For the maleate and phthalate anions exhibiting intramolecular hydrogen bonds, evidence for symmetric single well potentials is obtained. We propose a correlation between H/D isotope effects on carboxylic carbon chemical shifts and the proton transfer coordinate, q(1) = ½(r(OH) - r(HO)), which allows us to estimate the desired OHO hydrogen bond geometries from the observed (13)C NMR parameters, taking into account the degenerate proton tautomerism.

  1. A 13C NMR spectrometric method for the determination of intramolecular δ13C values in fructose from plant sucrose samples.

    PubMed

    Gilbert, Alexis; Silvestre, Virginie; Robins, Richard J; Tcherkez, Guillaume; Remaud, Gérald S

    2011-07-01

    Recent developments in (13) C NMR spectrometry have allowed the determination of intramolecular (13) C/(12) C ratios with high precision. However, the analysis of carbohydrates requires their derivatization to constrain the anomeric carbon. Fructose has proved to be particularly problematic because of a byproduct occurring during derivatization and the complexity of the NMR spectrum of the derivative. Here, we describe a method to determine the intramolecular (13) C/(12) C ratios in fructose by (13) C NMR analysis of the acetyl-isopropylidene derivative. We have applied this method to measure the intramolecular (13) C/(12) C distribution in the fructosyl moiety of sucrose and have compared this with that in the glucosyl moiety. Three prominent features stand out. First, in sucrose from both C(3) and C(4) plants, the C-1 and C-2 positions of the glucosyl and fructosyl moieties are markedly different. Second, these positions in C(3) and C(4) plants show a similar profile. Third, the glucosyl and fructosyl moieties of sucrose from Crassulacean acid metabolism (CAM) metabolism have a different profile. These contrasting values can be interpreted as a result of the isotopic selectivity of enzymes that break or make covalent bonds in glucose metabolism, whereas the distinctive (13) C pattern in CAM sucrose probably indicates a substantial contribution of gluconeogenesis to glucose synthesis.

  2. Dynamic pictures of membrane proteins in two-dimensional crystal, lipid bilayer and detergent as revealed by site-directed solid-state 13C NMR.

    PubMed

    Saitô, Hazime

    2004-11-01

    We have compared site-directed 13C solid-state NMR spectra of [3-13C]Ala- and/or [1-13C]Val-labeled membrane proteins, including bacteriorhodopsin (bR), pharaonis phoborhodopin (ppR), its cognate transducer (pHtrII) and Escherichia coli diacylglycerol kinase (DGK), in two-dimensional (2D) crystal, lipid bilayers, and detergent. Restricted fluctuation motions of these membrane proteins due to oligomerization of bR by specific protein-protein interactions in the 2D crystalline lattice or protein complex between ppR and pHtrII provide the most favorable environment to yield well-resolved, fully visible 13C NMR signals for [3-13C]Ala-labeled proteins. In contrast, several signals from such membrane proteins were broadened or lost owing to interference of inherent fluctuation frequencies (10(4)-10(5)Hz) with frequency of either proton decoupling or magic angle spinning, if their 13C NMR spectra were recorded as a monomer in lipid bilayers at ambient temperature. The presence of such protein dynamics is essential for the respective proteins to achieve their own biological functions. Finally, spectral broadening found for bR and DGK in detergents were discussed.

  3. Conformational distribution of baclofen analogues by 1H and 13C NMR analysis and ab initio HF MO STO-3G or STO-3G* calculations

    NASA Astrophysics Data System (ADS)

    Vaccher, Claude; Berthelot, Pascal; Debaert, Michel; Vermeersch, Gaston; Guyon, René; Pirard, Bernard; Vercauteren, Daniel P.; Dory, Magdalena; Evrard, Guy; Durant, François

    1993-12-01

    The conformations of 3-(substituted furan-2-yl) and 3-(substituted thien-2-yl)-γ-aminobutyric acid 1-9 in solution (D 2O) are estimated from high-resolution (300 MHz) 1H NMR coupling data. Conformations and populations of conformers are calculated by means of a modified Karplus-like relationship for the vicinal coupling constants. The results are compared with X-ray crystallographic investigations (torsion angles) and ab initio HF MO ST-3G or STO-3G* calculations. 1H NMR spectral analysis shows how 1-9 in solution retain the preferred g- conformation around the C3C4 bond, as found in the solid state, while a partial rotation is set up around the C2C3 bond: the conformations about C2C3 are all highly populated in solution. The 13C spin-lattice relaxation times are also discussed.

  4. Response to the Letter to the Editor regarding "Determination of the fatty acid profile by 1H-NMR spectroscopy."

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In expansion of previous work (G. Knothe, J.A. Kenar, Determination of the fatty acid profile by 1H-NMR spectroscopy, Eur. J. Lipid Sci. Technol. 2004, 106, 88-96), an additional approach is discussed for quantitating saturated fatty acids in the fatty acid profiles of common vegetable oils by 1H-NM...

  5. Quality evaluation and prediction of Citrullus lanatus by 1H NMR-based metabolomics and multivariate analysis.

    PubMed

    Tarachiwin, Lucksanaporn; Masako, Osawa; Fukusaki, Eiichiro

    2008-07-23

    (1)H NMR spectrometry in combination with multivariate analysis was considered to provide greater information on quality assessment over an ordinary sensory testing method due to its high reliability and high accuracy. The sensory quality evaluation of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) was carried out by means of (1)H NMR-based metabolomics. Multivariate analyses by partial least-squares projections to latent structures-discrimination analysis (PLS-DA) and PLS-regression offered extensive information for quality differentiation and quality evaluation, respectively. The impact of watermelon and rootstock cultivars on the sensory qualities of watermelon was determined on the basis of (1)H NMR metabolic fingerprinting and profiling. The significant metabolites contributing to the discrimination were also identified. A multivariate calibration model was successfully constructed by PLS-regression with extremely high reliability and accuracy. Thus, (1)H NMR-based metabolomics with multivariate analysis was considered to be one of the most suitable complementary techniques that could be applied to assess and predict the sensory quality of watermelons and other horticultural plants.

  6. Application of (1)h NMR profiling to assess seed metabolomic diversity. A case study on a soybean era population.

    PubMed

    Harrigan, George G; Skogerson, Kirsten; MacIsaac, Susan; Bickel, Anna; Perez, Tim; Li, Xin

    2015-05-13

    (1)H NMR spectroscopy offers advantages in metabolite quantitation and platform robustness when applied in food metabolomics studies. This paper provides a (1)H NMR-based assessment of seed metabolomic diversity in conventional and glyphosate-resistant genetically modified (GM) soybean from a genetic lineage representing ∼35 years of breeding and differing yield potential. (1)H NMR profiling of harvested seed allowed quantitation of 27 metabolites, including free amino acids, sugars, and organic acids, as well as choline, O-acetylcholine, dimethylamine, trigonelline, and p-cresol. Data were analyzed by canonical discriminant analysis (CDA) and principal variance component analysis (PVCA). Results demonstrated that (1)H NMR spectroscopy was effective in highlighting variation in metabolite levels in the genetically diverse sample set presented. The results also confirmed that metabolite variability is influenced by selective breeding and environment, but not genetic modification. Therefore, metabolite variability is an integral part of crop improvement that has occurred for decades and is associated with a history of safe use.

  7. Extraction and [superscript 1]H NMR Analysis of Fats from Convenience Foods: A Laboratory Experiment for Organic Chemistry

    ERIC Educational Resources Information Center

    Hartel, Aaron M.; Moore, Amy C.

    2014-01-01

    The extraction and analysis of fats from convenience foods (crackers, cookies, chips, candies) has been developed as an experiment for a second-year undergraduate organic chemistry laboratory course. Students gravimetrically determine the fat content per serving and then perform a [superscript 1]H NMR analysis of the recovered fat to determine the…

  8. Microscale Synthesis and (super 1)H NMR Analysis of Zn(super II) and Ni(super II) Tetraphenylporphyrins

    ERIC Educational Resources Information Center

    Saucedo, Laura; Mink, Larry M.

    2005-01-01

    A multisection undergraduate laboratory involving the microscale synthesis and spectroscopic analysis of unmetalled porphyrins and their corresponding metalloporphyins is described. The microscale synthesis involving the isolation of the metalloporphyrins as solids and their corresponding (super 1)H NMR spectra are presented.

  9. Water Solvent Effect on Theoretical Evaluation of (1)H NMR Chemical Shifts: o-Methyl-Inositol Isomer.

    PubMed

    Dos Santos, Hélio F; Chagas, Marcelo A; De Souza, Leonardo A; Rocha, Willian R; De Almeida, Mauro V; Anconi, Cleber P A; De Almeida, Wagner B

    2017-04-13

    In this paper, density functional theory calculations of nuclear magnetic resonance (NMR) chemical shifts for l-quebrachitol isomer, previously studied in our group, are reported with the aim of investigating in more detail the water solvent effect on the prediction of (1)H NMR spectra. In order to include explicit water molecules, 20 water-l-quebrachitol configurations obtained from Monte Carlo simulation were selected to perform geometry optimizations using the effective fragment potential method encompassing 60 water molecules around the solute. The solvated solute optimized geometries were then used in B3LYP/6-311+G(2d,p) NMR calculations with PCM-water. The inclusion of explicit solvent in the B3LYP NMR calculations resulted in large changes in the (1)H NMR profiles. We found a remarkable improvement in the agreement with experimental NMR profiles when the explicit hydrated l-quebrachitol structure is used in B3LYP (1)H NMR calculations, yielding a mean absolute error (MAE) of only 0.07 ppm, much lower than reported previously for the gas phase optimized structure (MAE = 0.11 ppm). In addition, a very improved match between theoretical and experimental (1)H NMR spectrum measured in D2O was achieved with the new hydrated optimized l-quebrachitol structure, showing that a fine-tuning of the theoretical NMR spectra can be accomplished once solvent effects are properly considered.

  10. Essential Parameters for Structural Analysis and Dereplication by 1H NMR Spectroscopy

    PubMed Central

    2015-01-01

    The present study demonstrates the importance of adequate precision when reporting the δ and J parameters of frequency domain 1H NMR (HNMR) data. Using a variety of structural classes (terpenoids, phenolics, alkaloids) from different taxa (plants, cyanobacteria), this study develops rationales that explain the importance of enhanced precision in NMR spectroscopic analysis and rationalizes the need for reporting Δδ and ΔJ values at the 0.1–1 ppb and 10 mHz level, respectively. Spectral simulations paired with iteration are shown to be essential tools for complete spectral interpretation, adequate precision, and unambiguous HNMR-driven dereplication and metabolomic analysis. The broader applicability of the recommendation relates to the physicochemical properties of hydrogen (1H) and its ubiquity in organic molecules, making HNMR spectra an integral component of structure elucidation and verification. Regardless of origin or molecular weight, the HNMR spectrum of a compound can be very complex and encode a wealth of structural information that is often obscured by limited spectral dispersion and the occurrence of higher order effects. This altogether limits spectral interpretation, confines decoding of the underlying spin parameters, and explains the major challenge associated with the translation of HNMR spectra into tabulated information. On the other hand, the reproducibility of the spectral data set of any (new) chemical entity is essential for its structure elucidation and subsequent dereplication. Handling and documenting HNMR data with adequate precision is critical for establishing unequivocal links between chemical structure, analytical data, metabolomes, and biological activity. Using the full potential of HNMR spectra will facilitate the general reproducibility for future studies of bioactive chemicals, especially of compounds obtained from the diversity of terrestrial and marine organisms. PMID:24895010

  11. Nanoliter-volume 1H NMR detection using periodic stopped-flow capillary electrophoresis.

    PubMed

    Olson, D L; Lacey, M E; Webb, A G; Sweedler, J V

    1999-08-01

    Recent advances in the analysis of nanoliter volumes using 1H NMR microcoils have led to the application of microcoils as detectors for capillary electrophoresis (CE). Custom NMR probes consisting of 1-mm-long solenoidal microcoils are fabricated from 50-micron diameter wire wrapped around capillaries to create nanoliter-volume detection cells. For geometries in which the capillary and static magnetic field are not parallel, the electrophoretic current induces a magnetic field gradient which degrades the spectroscopic information obtainable from CE/NMR. To reduce this effect and allow longer analyte observation times, the electrophoretic voltage is periodically interrupted so that 1-min high-resolution NMR spectra are obtained for every 15 s of applied voltage. The limits of detection (LODs; based on S/N = 3) for CE/NMR for arginine are 57 ng (330 pmol; 31 mM) and for triethylamine (TEA) are 9 ng (88 pmol; 11 mM). Field-amplified stacking is used for sample preconcentration. As one example, a 290-nL injection of a mixture of arginine and TEA both at 50 mM (15 nmol of each injected) is stacked severalfold for improved concentration LODs while achieving a separation efficiency greater than 50,000. Dissolving a sample in a mixture of 10% H2O/90% D2O allows H2O to serve as the nearly ideal neutral tracer and allows direct observation of the parabolic and flat flow profiles associated with gravimetric and electrokinetic injection, respectively. The unique capabilities of CE and the rich spectral information provided by NMR spectroscopy combine to yield a valuable analytical tool, especially in the study of mass-limited samples.

  12. Organic solute changes with acidification in Lake Skjervatjern as shown by 1H-NMR spectroscopy

    USGS Publications Warehouse

    Malcolm, R.L.; Hayes, T.

    1994-01-01

    1H-NMR spectroscopy has been found to be a useful tool to establish possible real differences and trends between all natural organic solute fractions (fulvic acids, humic acids, and XAD-4 acids) after acid-rain additions to the Lake Skjervatjern watershed. The proton NMR technique used in this study determined the spectral distribution of nonexchangeable protons among four peaks (aliphatic protons; aliphatic protons on carbon ?? or attached to electronegative groups; protons on carbons attached to O or N heteroatoms; and aromatic protons). Differences of 10% or more in the respective peak areas were considered to represent a real difference. After one year of acidification, fulvic acids decreased 13% (relative) in Peak 3 protons on carbon attached to N and O heteratoms and exhibited a decrease in aromatic protons between 27% and 31%. Humic acids also exhibited an 11% relative decrease in aromatic protons as a result of acidification. After one year of acidification, real changes were shown in three of the four proton assignments in XAD-4 acids. Peak 1 aliphatic protons increased by 14% (relative), Peak 3 protons on carbons attached to O and N heteroatoms decreased by 13% (relative), and aromatic protons (Peak 4) decreased by 35% (relative). Upon acidification, there was a trend in all solutes for aromatic protons to decrease and aliphatic protons to increase. The natural variation in organic solutes as shown in the Control Side B of the lake from 1990 to 1991 is perhaps a small limitation to the same data interpretations of acid rain changes at the Lake Skjervatjern site, but the proton NMR technique shows great promise as an independent scientific tool to detect and support other chemical techniques in establishing organic solute changes with different treatments (i.e., additions of acid rain).

  13. 1H NMR to investigate metabolism and energy supply in rhesus macaque sperm.

    PubMed

    Lin, Ching-Yu; Hung, Pei-hsuan; VandeVoort, Catherine A; Miller, Marion G

    2009-07-01

    Sperm ATP is derived primarily from either glycolysis or mitochondrial oxidative phosphorylation. In the present studies, (1)H NMR spectroscopy was used to characterize the metabolite profile in primate sperm treated either with alpha-chlorohydrin (ACH), a known inhibitor of sperm glycolysis or pentachlorophenol (PCP), an uncoupler of oxidative phosphorylation. Sperm were collected from monkeys in the fall and spring, washed and incubated with either the media control, ACH (0.5mM) or PCP (50 microM). Using principal components analysis, PC1 scores plot indicated that the greatest level of variance was found between fall and spring samples and not chemical-treated samples. However, PC4 scores plot did show a consistent effect of ACH treatment. From the PC1 loadings plot, metabolites contributing to the seasonal differences were higher levels of formate in the fall and higher levels of carnitine and acetylcarnitine in the spring as well as possible differences in lipoprotein content. The PC4 loadings plot indicated that ACH treatment decreased lactate and ATP consistent with inhibition of glycolysis. Carnitine also was decreased and acetylcarnitine increased although the latter was not statistically significant. With PCP-treated sperm, no difference between control and treated samples could be discerned suggesting either that primate sperm are insensitive to uncoupling agents or that glycolysis played the more important role in maintaining sperm ATP levels. Overall, NMR studies may prove useful in the development of metabolomic markers that signal sperm metabolic impairments and have the potential to provide useful biomarkers for reproductive health.

  14. Determination of polydimethylsiloxanes by 1H-NMR in wine and edible oils.

    PubMed

    Mojsiewicz-Pieńkowska, K; Jamrógiewicz, Z; Łukasiak, J

    2003-05-01

    Fourier transform (1)H-nuclear magnetic resonance (NMR) spectroscopy was suitable for the quantitative determination of polydimethylsiloxanes (PDMS) in wine and edible oil samples. This approach offers highly specific qualitative and quantitative analysis due to silicone-specific location of proton signals linked to carbon atoms located directly next to silicon atoms (0-0.5 ppm), as well as a different location of signals in the range for different organosilicon structures. The method can be used for the control of PDMS at regulatory limits in foodstuffs (10 mg kg(-1)) using hexamethyldisiloxane (HDMS) as an internal standard. Samples were prepared by extraction under suitable conditions to separate the analyte, and with analyte enrichment before (1)H-NMR analysis. Analytical procedures were developed to permit the determination of PDMS at 0.06 mg kg(-1) in wine and at 6 mg kg(-1) in edible oils samples using readily available NMR instrumentation. It was, however, possible to lower the limit of detection to 6 microg kg(-1) for wine and to 60 microg kg(-1) for edible oils using a higher field instrument (500 MHz). Relative standard deviations (S(r)) were obtained for wine (0.028) and for oil samples (0.043), which when compared with values obtained for samples spiked with PDMS (0.021) indicated that the sample preparation was the main factor determining the precision of the method. The average recovery rates for PDMS were 97 and 95% for wine and edible oils, respectively. PDMS was detected in four brands of Italian wine, with Chianti-Rafaello containing the highest concentration (0.35 mg kg(-1)), and in four types of edible oils, highest concentration (11.9 mg kg(-1)) being found in Italian corn oil. None of the levels of PDMS found in the food samples exceeded the permissible standards laid down by the Codex Alimentarius Commission (10 mg kg(-1)), with the exception of the one corn oil sample.

  15. Evaluation of 1H NMR metabolic profiling using biofluid mixture design.

    PubMed

    Athersuch, Toby J; Malik, Shahid; Weljie, Aalim; Newton, Jack; Keun, Hector C

    2013-07-16

    A strategy for evaluating the performance of quantitative spectral analysis tools in conditions that better approximate background variation in a metabonomics experiment is presented. Three different urine samples were mixed in known proportions according to a {3, 3} simplex lattice experimental design and analyzed in triplicate by 1D (1)H NMR spectroscopy. Fifty-four urinary metabolites were subsequently quantified from the sample spectra using two methods common in metabolic profiling studies: (1) targeted spectral fitting and (2) targeted spectral integration. Multivariate analysis using partial least-squares (PLS) regression showed the latent structure of the spectral set recapitulated the experimental mixture design. The goodness-of-prediction statistic (Q(2)) of each metabolite variable in a PLS model was calculated as a metric for the reliability of measurement, across the sample compositional space. Several metabolites were observed to have low Q(2) values, largely as a consequence of their spectral resonances having low s/n or strong overlap with other sample components. This strategy has the potential to allow evaluation of spectral features obtained from metabolic profiling platforms in the context of the compositional background found in real biological sample sets, which may be subject to considerable variation. We suggest that it be incorporated into metabolic profiling studies to improve the estimation of matrix effects that confound accurate metabolite measurement. This novel method provides a rational basis for exploiting information from several samples in an efficient manner and avoids the use of multiple spike-in authentic standards, which may be difficult to obtain.

  16. 13C-NMR spectroscopic evaluation of the citric acid cycle flux in conditions of high aspartate transaminase activity in glucose-perfused rat hearts.

    PubMed

    Tran-Dinh, S; Hoerter, J A; Mateo, P; Gyppaz, F; Herve, M

    1998-12-01

    A new mathematical model, based on the observation of 13C-NMR spectra of two principal metabolites (glutamate and aspartate), was constructed to determine the citric acid cycle flux in the case of high aspartate transaminase activity leading to the formation of large amounts of labeled aspartate and glutamate. In this model, the labeling of glutamate and aspartate carbons by chemical and isotopic exchange with the citric acid cycle are considered to be interdependent. With [U-13C]Glc or [1,2-(13)C]acetate as a substrate, all glutamate and aspartate carbons can be labeled. The isotopic transformations of 32 glutamate isotopomers into 16 aspartate isotopomers or vice versa were studied using matrix operations; the results were compiled in two matrices. We showed how the flux constants of the citric acid cycle and the 13C-enrichment of acetyl-CoA can be deduced from 13C-NMR spectra of glutamate and/or aspartate. The citric acid cycle flux in beating Wistar rat hearts, aerobically perfused with [U-13C]glucose in the absence of insulin, was investigated by 13C-NMR spectroscopy. Surprisingly, aspartate instead of glutamate was found to be the most abundantly-labeled metabolite, indicating that aspartate transaminase (which catalyses the reversible reaction: (glutamate + oxaloacetate <--> 2-oxoglutarate + aspartate) is highly active in the absence of insulin. The amount of aspartate was about two times larger than glutamate. The quantities of glutamate (G0) or aspartate (A0) were approximately the same for all hearts and remained constant during perfusion: G0 = (0.74 +/- 0.03) micromol/g; A0 = (1.49 +/- 0.05) micromol/g. The flux constants, i.e., the fraction of glutamate and aspartate in exchange with the citric acid cycle, were about 1.45 min(-1) and 0.72 min(-1), respectively; the flux of this cycle is about (1.07 +/- 0.02) micromol min(-1) g(-1). Excellent agreement between the computed and experimental data was obtained, showing that: i) in the absence of insulin

  17. Characterization of the humic substances isolated from postfire soils of scotch pine forest in Togljatty city, Samara region by the 13C-NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Maksimova, Ekaterina; Abakumov, Evgeny

    2016-04-01

    Postpyrogenic soil dynamics is an informative tool for studying of soil elementary processes in extreme temperature conditions and for predicting of short time environmental changes in conditions of catastrophic landscape changes. Soil organic matter (SOM) system evolution is the most rapid process of postpyrogenic soil development. In this relation the evaluation of humus accumulation rates and humification trend were conducted with use of the classical chemical and modern spectroscopy methods. Soil restoration after spontaneous forest fires near Togljatty city (Samara region, Russia) was abandoned in 2010, and further monitoring over the next four years was organized to evaluate the speed of biogenic processes and humus accumulation dynamics. Three key soil plots were studied for estimating SOM quality changes under the forest fire effect: surface forest fire, crown forest fire and control. Total carbon and nitrogen content as well as Cha/Cfa ratios (content of humic acids/ content of fulvic acids), were estimated to assess the dynamics of soil restoration. Humic acid powders were extracted and analyzed by elemental composition and 13C-NMR spectroscopy to assess changes in humic substance structure and composition. The data obtained indicate that burning of a forest floor and sod (humic) horizon led to humus losses and decreases in total carbon stocks. As a result of the fires, the content of humic acids in the pyrogenic horizon increased, leading alterations of humus type. Greater increases in the degree of organic matter humification were observed for surface fires than crown fires. It was shown that the humus molecular composition was substantially affected by the wildfires. The data show an increase in aromaticity, a loss of oxygen-containing groups and dehydrogenation of humic acids. Humic acids in the soils of the control plots and after wildfires were significantly different, especially in the ratios of hydrogen, oxygen and carbon. The increase in the

  18. Application of Spectroscopic Techniques (FT-IR, 13C NMR) to the analysis of humic substances in volcanic soils along an environmental gradient (Tenerife, Canary Islands, Spain)

    NASA Astrophysics Data System (ADS)

    Rodriguez Rodriguez, Antonio; María Armas Herrera, Cecilia; González Pérez, José Antonio; González-Vila, Francisco Javier; Arbelo Rodríguez, Carmen Dolores; Mora Hernández, Juan Luis; Polvillo Polo, Oliva

    2010-05-01

    Andosols and andic soils are considered as efficient C-sinks in terms of C sequestration. These soils are usually developed from volcanic materials, and are characterized by a predominance of short-range ordered minerals like allophanes, imogolite and other Fe and Al oxyhydroxides. Such materials occur commonly associated with organic compounds, thus generating highly stable organo-mineral complexes and leading to the accumulation of a high amount of organic carbon. Spectroscopic methods like FT-IR and 13C NMR are suitable for the analysis of the chemical structure of soil humic substances, and allow identifying distinct functional groups and protein, lipids, lignin, carbohydrate-derived fragments. In this work we study the structural features of four soils developed on Pleistocene basaltic lavae in Tenerife (Canary Island, Spain), distributed along an altitudinal climatic gradient. The soil sequence comprises soils with different degree of geochemical evolution and andic character, including a mineral ‘Hypersalic Solonchak' (Tabaibal de Rasca), a slightly vitric ‘Luvic Phaeozem' (Los Frailes), a degraded and shallow ‘Endoleptic, fulvic, silandic Andosol' (Siete Lomas), and a well-developed and deep ‘Fulvic, silandic, Andosol' (Ravelo). Samples of the raw soil and humic and fulvic acids isolated from the surface horizons were analyzed. The results show a low content of organic carbon in the mineral soil, the inherited humin predominating, and a very high content of humic and fulvic acids in Andosols. The FT-IR and 13C NMR spectra of the raw soil samples show a low resolution, related to interferences from mineral complexes signals, particularly in soils with lower organic carbon content. 13C NMR shows a predominance of O-alkyl carbon (derived of carbohydrates) in andic soils, whereas O-alkyl and aromatic fractions are most evident in the mineral soil. The humic acids spectra are characterized by a dominance of alkyl and aromatic fractions with a high degree

  19. In Situ 13C NMR at Elevated-Pressures and -Temperatures Investigating the Conversion of CO2 to Magnesium and Calcium Carbonate Minerals

    NASA Astrophysics Data System (ADS)

    Surface, J. A.; Conradi, M. S.; Skemer, P. A.; Hayes, S. E.

    2013-12-01

    We have constructed specialized NMR hardware to conduct in situ elevated-pressure, elevated-temperature 13C NMR studies of unmixed heterogeneous mixtures of solids, liquids, gases, and supercritical fluids. Specifically, our aim is to monitor CO2 uptake in both ultramafic rocks and in more porous geological materials to understand the mechanisms of chemisorption as a function of temperature, pressure and pH. In this in situ NMR probe, we are able to simulate processes at geologically relevant fluid pressures and temperatures, monitoring the kinetics of CO2 conversion to carbonates. The in situ NMR experiments consist of heterogeneous mixtures of rock, salty brine solution, and moderate pressure CO2 gas at elevated temperatures. The purpose of studying these reactions is to determine efficacy of carbonate formation in various geological reservoirs. Via 13C NMR, we have spectroscopically characterized and quantified the conversion of CO2 to magnesium carbonate and calcium carbonate minerals. When CO2 reacts with the calcium or magnesium in a mineral or rock sample, the 13C chemical shift, linewidth, lineshape, and relaxation times change dramatically. This change can be monitored in situ and provide instantaneous and continuous characterization that maps the chemistry that is taking place. For example, on the pathway to MgCO3 formation, there are a number of phases of Mg(OH)x(H2O)y(CO3)z that are apparent via NMR spectroscopy. We will demonstrate that NMR can be used for quantitative characterization of multiple metastable mineral phases in pure forms and in mixtures. Results are confirmed via powder XRD and Raman spectroscopy of aquo- hydro- carbonato- magnesium species and calcium carbonate species. We also have monitored the 13C spectroscopy to analyze the phase of CO2 (liquid, supercritical, or gas) and its conversion into other forms, such as bicarbonate and carbonate species, providing a "window" into the in situ pH of the reacting system. Reference: 'In Situ

  20. The influence of sulfur configuration in (1) H NMR chemical shifts of diasteromeric five-membered cyclic sulfites.

    PubMed

    Obregón-Mendoza, Marco A; Sánchez-Castellanos, Mariano; Cuevas, Gabriel; Gnecco, Dino; Cassani, Julia; Poveda-Jaramillo, Juan C; Reynolds, William F; Enríquez, Raúl G

    2017-03-01

    The effect of the stereochemistry of the sulfur atom on (1) H chemical shifts of the diasteromeric pair of cyclic sulfites of 4-[methoxy(4-nitrophenyl)methyl]-5-phenyl-1,3,2-dioxathiolan-2-oxide was investigated. The complete (1) H and (13) C NMR spectral assignment was achieved by the use of one-dimensional and two-dimensional NMR techniques in combination with X-ray data. A correlation of experimental data with theoretical calculations of chemical shift tensors using density functional theory and topological theory of atoms in molecules was made. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Unexpected formation of 1-diethylaminobutadiene in photosensitized oxidation of triethylamine induced by 2,3-dihydro-oxoisoaporphine dyes. A 1H NMR and isotopic exchange study.

    PubMed

    De la Fuente, Julio R; Jullian, Carolina; Saitz, Claudio; Neira, Verónica; Poblete, Oscar; Sobarzo-Sánchez, Eduardo

    2005-10-28

    [reaction: see text] Photoreduction of oxoisoaporphine dyes occurs via a stepwise mechanism of electron-proton-electron transfer that leads to the N-hydrogen oxoisoaporphine anion. When triethylamine, TEA, was used as the electron donor in anaerobic conditions, 1-diethylaminobutadiene, DEAB, was one of the oxidation products of TEA, among diethylamine and acetaldehyde. DEAB was identified by (1)H NMR and GC-MS experiments by comparison with the authentic 1-diethylaminobutadiene. This is the first report of a butadienyl derivative formed in the dye-sensitized photooxidation of TEA. In addition, isotopic exchange experiments with TEA-d(15) and D(2)O show that the hydrogens at carbon-2 and carbon-4 of the butadienyl moiety are exchangeable. The observed isotopic exchange pattern could be explained by the head-to-tail coupling of an N,N-diethylvinylamine intermediate that exchanges hydrogens at the C-beta via the enammonium ion.

  2. Coal liquefaction process streams characterization and evaluation: [sup 13]C-NMR analysis of CONSOL THF-soluble residual materials from the Wilsonville coal liquefaction process

    SciTech Connect

    Solum, M.S.; Pugmire, R.J. )

    1992-11-01

    This study demonstrated the feasibility of using CP/MAS [sup 13]C-NMR spectroscopy for the chemical structural examination of distillation resid materials derived from direct coal liquefaction. A set of twelve carbon skeletal-structure parameters and eight molecular structural descriptors were derived from the NMR data. The technique was used previously to determine these parameters for coal and char, and in the construction of a coal pyrolysis model. The method was applied successfully to the tetrahydrofuran (THF)-soluble portion of eleven 850[degrees]F[sup +] distillation resids and one 850[degrees]F[sup +] distillation resid which contained ash and insoluble organic material (IOM). The results of this study demonstrate that this analytical method can provide data for construction of a model of direct coal liquefaction. Its further development and use is justified based on these results.

  3. Coal liquefaction process streams characterization and evaluation: {sup 13}C-NMR analysis of CONSOL THF-soluble residual materials from the Wilsonville coal liquefaction process

    SciTech Connect

    Solum, M.S.; Pugmire, R.J.

    1992-11-01

    This study demonstrated the feasibility of using CP/MAS {sup 13}C-NMR spectroscopy for the chemical structural examination of distillation resid materials derived from direct coal liquefaction. A set of twelve carbon skeletal-structure parameters and eight molecular structural descriptors were derived from the NMR data. The technique was used previously to determine these parameters for coal and char, and in the construction of a coal pyrolysis model. The method was applied successfully to the tetrahydrofuran (THF)-soluble portion of eleven 850{degrees}F{sup +} distillation resids and one 850{degrees}F{sup +} distillation resid which contained ash and insoluble organic material (IOM). The results of this study demonstrate that this analytical method can provide data for construction of a model of direct coal liquefaction. Its further development and use is justified based on these results.

  4. Molecular interactions of a model bile salt and porcine bile with (1,3:1,4)-β-glucans and arabinoxylans probed by (13)C NMR and SAXS.

    PubMed

    Gunness, Purnima; Flanagan, Bernadine M; Mata, Jitendra P; Gilbert, Elliot P; Gidley, Michael J

    2016-04-15

    Two main classes of interaction between soluble dietary fibres (SDFs), such as (1,3:1,4)-β-D-glucan (βG) and arabinoxylan (AX) and bile salt (BS) or diluted porcine bile, were identified by (13)C NMR and small angle X-ray scattering (SAXS). Small chemical shift differences of BS NMR resonances were consistent with effective local concentration or dilution of BS micelles mostly by βG, suggesting dynamic interactions; whilst the reduced line widths/intensities observed were mostly caused by wheat AX and the highest molecular size and concentrations of βG. SAXS showed evidence of changes in βG but not AX in the presence of BS micelles, at >13 nm length scale consistent with molecular level interactions. Thus intermolecular interactions between SDF and BS depend on both SDF source and its molecular weight and may occur alone or in combination.

  5. Kinetic analysis of reactions of Si-based epoxy resins by near-infrared spectroscopy, 13C NMR and soft-hard modelling.

    PubMed

    Garrido, Mariano; Larrechi, Maria Soledad; Rius, F Xavier; Mercado, Luis Adolfo; Galià, Marina

    2007-02-05

    Soft- and hard-modelling strategy was applied to near-infrared spectroscopy data obtained from monitoring the reaction between glycidyloxydimethylphenyl silane, a silicon-based epoxy monomer, and aniline. On the basis of the pure soft-modelling approach and previous chemical knowledge, a kinetic model for the reaction was proposed. Then, multivariate curve resolution-alternating least squares optimization was carried out under a hard constraint, that compels the concentration profiles to fulfil the proposed kinetic model at each iteration of the optimization process. In this way, the concentration profiles of each species and the corresponding kinetic rate constants of the reaction, unpublished until now, were obtained. The results obtained were contrasted with 13C NMR. The joint interval test of slope and intercept for detecting bias was not significant (alpha=5%).

  6. Molecular organization in the native state of woody tissue: Studies of tertiary structure using the Raman microprobe Solid State [sup 13]C NMR and biomimetic tertiary aggregates

    SciTech Connect

    Atalla, R.H.

    1992-01-01

    A number of new approaches to the study of native wood tissue complementary to our earlier Raman spectroscopy including solid state [sup 13]C NMR and X-ray diffractometry. A wide variety of native cellulosic tissues were examined which led to the generation of biomimetic tertiary aggregates which simulate states of aggregation characteristic of cell walls. We have also explored charge transport characteristics of lignified tissue. Our Raman spectroscopic studies have advanced our understanding of key spectral features and confirmed the variability of the patterns of orientation of lignin reported earlier. A major effort was dedicated to assessing the contributions of electronic factors such as conjugation and the resonance Raman effect to enhancement of the spectra features associated with lignin. We have now established a solid foundation for spectral mapping of different regions in cell walls.

  7. Quantum-chemical analysis of paramagnetic 13C NMR shifts of iron-bound cyanide ions in heme-protein environments

    NASA Astrophysics Data System (ADS)

    Yamaki, Daisuke; Hada, Masahiko

    2012-12-01

    Paramagnetic 13C NMR chemical shifts of iron-bound cyanide ions located in biological environments such as heme-proteins are significantly sensitive to the environments. These chemical shifts are due to negative spin density at 13C induced by the open-shell iron center. In order to examine the environments effects on the electronic states around heme parts, ab initio calculations were performed for model systems of heme-proteins. The proximal residues in proteinparts of cytochrome c, hemoglobin, myoglobin and horseradish peroxidase were included in the model systems with the common active site (cyanide imidazole porphyrinato iron(III)) to take account of the environments effects. The calculated paramagnetic shifts of model systems reproduce the experimental trend of corresponding heme-proteins. It is found that the effects of proximal residues on the electronic states of the heme-parts are significant for these hemeproteins. In this abstract we focused on the calculations and analysis of cytochrome c.

  8. Properties of sesame oil by detailed 1H and 13C NMR assignments before and after ozonation and their correlation with iodine value, peroxide value, and viscosity measurements.

    PubMed

    Sega, Alessandro; Zanardi, Iacopo; Chiasserini, Luisa; Gabbrielli, Alessandro; Bocci, Velio; Travagli, Valter

    2010-02-01

    Gaseous ozone chemically reacts with unsaturated triglyceride substrates leading to ozonated derivatives with a wide potential applications, ranging from the petrochemical to the pharmaceutical industry. To date, an ultimate understanding of the ozone reactivity during sesame oil ozonation process as well as detailed (1)H and (13)C NMR assignments are lacking. A practical advantage of NMR is that a single NMR sample measurement can explain many issues, while similar analysis by traditional methods may require several independent and time-consuming measurements. Moreover, significant relationships among NMR spectra and both conventional chemical analysis and viscosity measurements have been found. Eventually, NMR could play an important role for quality attributes of ozonated oil derivatives.

  9. Geometries and tautomerism of OHN hydrogen bonds in aprotic solution probed by H/D isotope effects on (13)C NMR chemical shifts.

    PubMed

    Tolstoy, Peter M; Guo, Jing; Koeppe, Benjamin; Golubev, Nikolai S; Denisov, Gleb S; Smirnov, Sergei N; Limbach, Hans-Heinrich

    2010-10-14

    The (1)H and (13)C NMR spectra of 17 OHN hydrogen-bonded complexes formed by CH(3)(13)COOH(D) with 14 substituted pyridines, 2 amines, and N-methylimidazole have been measured in the temperature region between 110 and 150 K using CDF(3)/CDF(2)Cl mixture as solvent. The slow proton and hydrogen bond exchange regime was reached, and the H/D isotope effects on the (13)C chemical shifts of the carboxyl group were measured. In combination with the analysis of the corresponding (1)H chemical shifts, it was possible to distinguish between OHN hydrogen bonds exhibiting a single proton position and those exhibiting a fast proton tautomerism between molecular and zwitterionic forms. Using H-bond correlations, we relate the H/D isotope effects on the (13)C chemical shifts of the carboxyl group with the OHN hydrogen bond geometries.

  10. Structural characterization and molecular order of rodlike mesogens with three- and four-ring core by XRD and 13C NMR spectroscopy.

    PubMed

    Reddy, M Kesava; Reddy, K Subramanyam; Yoga, K; Prakash, M; Narasimhaswamy, T; Mandal, A B; Lobo, Nitin P; Ramanathan, K V; Rao, D S Shankar; Prasad, S Krishna

    2013-05-09

    Structural characterizations using XRD and (13)C NMR spectroscopy of two rodlike mesogens consisting of (i) three phenyl ring core with a polar cyano terminal and (ii) four phenyl ring core with flexible dodecyl terminal chain are presented. The three-ring-core mesogen with cyano terminal exhibits enantiotropic smectic A phase while the four-ring mesogen reveals polymesomorphism and shows enantiotropic nematic, smectic C, and tilted hexatic phases. The molecular organization in the three-ring mesogen is found to be partial bilayer smectic Ad type, and the interdigitation of the molecules in the neighboring layers is attributed to the presence of the polar terminal group. For the four-ring mesogen, the XRD results confirm the existence of the smectic C and the tilted hexatic mesophases. A thermal variation of the layer spacing across the smectic C phase followed by a discrete jump at the transition to the tilted hexatic phase is also observed. The tilt angles have been estimated to be about 45° in the smectic C phase and about 40° in tilted hexatic phase. (13)C NMR results indicate that in the mesophase the molecules are aligned parallel to the magnetic field. From the (13)C-(1)H dipolar couplings determined from the 2D experiments, the overall order parameter for the three-ring mesogen in its smectic A phase has been estimated to be 0.72 while values ranging from 0.88 to 0.44 have been obtained for the four-ring mesogen as it passes from the tilted hexatic to the nematic phase. The orientations of the different rings of the core unit with respect to each other and also with respect to the long axis of the molecule have also been obtained.

  11. Metabolic pathways for ketone body production. /sup 13/C NMR spectroscopy of rat liver in vivo using /sup 13/C-multilabeled fatty acids

    SciTech Connect

    Pahl-Wostl, C.; Seelig, J.

    1986-11-04

    The hormonal regulation of ketogenesis in the liver of living rat has been studied noninvasively with /sup 13/C nuclear magnetic resonance. The spatial selection for the liver was better than 90%, with extrahepatic adipose tissue contribution only a very small amount of signal. The metabolic activities of the liver were investigated by infusion of /sup 13/C-labeled butyrate in the jugular vein of the anesthetized rat. The rate of butyrate infusion was chosen to be close to the maximum oxidative capacity of the rat liver, and the /sup 13/C signal intensities were enhanced by using doubly labeled (1,3-/sup 13/C)butyrate as a substrate. Different /sup 13/C NMR spectra and hence different metabolites were observed depending on the hormonal state of the animal. The /sup 13/C NMR studies demonstrate that even when rate of acetyl-CoA production are high, the disposal of this compound is not identical in fasted and diabetic animals. This supports previous suggestions that the redox state of the mitochondrion represents the most important factor in regulation. For a given metabolic state of the animal, different signal intensities were obtained depending on whether butyrate was labeled at C-1, C-3, or C-1,3. From the ratios of incorporation of /sup 13/C label into the carbons of 3-hydroxybutyrate, it could be estimated that a large fraction of butyrate evaded ..beta..-oxidation to acetyl-CoA but was converted directly to acetoacetyl-CoA. /sup 13/C-labeled glucose could be detected in vivo in the liver of diabetic rats.

  12. Determination of fructose metabolic pathways in normal and fructose-intolerant children: A sup 13 C NMR study using (U- sup 13 C)fructose

    SciTech Connect

    Gopher, A.; Lapidot, A. ); Vaisman, N. ); Mandel, H. )

    1990-07-01

    An inborn deficiency in the ability of aldolase B to split fructose 1-phosphate is found in humans with hereditary fructose intolerance (HFI). A stable isotope procedure to elucidate the mechanism of conversion of fructose to glucose in normal children and in HFI children has been developed. A constant infusion of D-(U-{sup 13}C)fructose was given nasogastrically to control and to HFI children. Hepatic fructose conversion to glucose was estimated by examination of {sup 13}C NMR spectra of plasma glucose. Significantly lower values ({approx}3-fold) for fructose conversion to glucose were obtained for the HFI patients as compared to the controls. A quantitative determination of the metabolic pathways of fructose conversion to glucose was derived from {sup 13}C NMR measurement of plasma ({sup 13}C)glucose isotopomer populations. The finding of isotopomer populations of three adjacent {sup 13}C atoms at glucose C-4 ({sup 13}C{sub 3}-{sup 13}C{sub 4}-{sup 13}C{sub 5}) suggests that there is a direct pathway from fructose, by-passing fructose-1-phosphate aldolase, to fructose 1,6-bisphosphate. The metabolism of fructose by fructose-1-phosphate aldolase activity accounts for only {approx}50% of the total amount of hepatic fructose conversion to glucose. In view of the marked decline by 67% in synthesis of glucose from fructose in HFI subjects found in this study, the extent of ({sup 13}C)glucose formation from a trace amount of (U-{sup 13}C)fructose infused into the patient can be used as a safe and noninvasive diagnostic test for inherent faulty fructose metabolism.

  13. Staphylococcal nuclease active-site amino acids: pH dependence of tyrosines and arginines by sup 13 C NMR and correlation with kinetic studies

    SciTech Connect

    Grissom, C.G.; Markley, J.L. )

    1989-03-07

    The pH and temperature dependence of the kinetic parameters of staphylococcal nuclease have been examined with three p-nitrophenyl phosphate containing DNA analogues that vary as to 3'-substituent. With wild-type (Foggi variant) nuclease (nuclease wt) and the substrates thymidine 3'-phosphate 5'-(p-nitrophenyl phosphate) (PNPdTp), thymidine 3'-methylphosphonate 5'-(p-nitrophenyl phosphate) (PNPdTp Me), and thymidine 5'-(p-nitrophenyl phosphate) (PNPdT), k{sub cat} remains nearly constant at 13 min{sup {minus}1}. However, k{sub cat}/k{sub m} with nuclease wt varies considerably. The data suggests that the inflection k{sub cat}/K{sub m} with pK{sub a} at 9.67 arises from ionization of tyrosine-85, which hydrogen bonds to the divalent 3'-phosphomonester of substrates with this substituent. The enthalpy of ionization of both deprotonation steps in the k{sub cat}/K{sub m} versus pH profile is 5 kcal/mol. {sup 13}C NMR has been used to determine the pK{sub a} values of the arginine and tyrosine residues. The results do not rule out arginine as a candidate for the acidic catalyst that protonates the 5'-ribose alkoxide prior to product release. The phenolic hydroxyl carbon of tyrosine-85 has been assigned by comparing the {sup 13}C NMR spectrum of nuclease wt and nuclease Y85F. This correlation between pK{sub a} values along with the absence of other candidates indicates that the ionization of tyrosine-85 is the pK{sub a} seen in the k{sub cat}/K{sub m} vs pH profile for substrates with a divalent 3'-phosphomonester. This conclusion is consistent with the proposed role of tyrosine-85 as a hydrogen-bond donor to the 3'-phosphomonoester of substrates poised for exonucleolytic hydrolysis.

  14. Conformation and dynamics of melittin bound to magnetically oriented lipid bilayers by solid-state (31)P and (13)C NMR spectroscopy.

    PubMed Central

    Naito, A; Nagao, T; Norisada, K; Mizuno, T; Tuzi, S; Saitô, H

    2000-01-01

    The conformation and dynamics of melittin bound to the dimyristoylphosphatidylcholine (DMPC) bilayer and the magnetic orientation in the lipid bilayer systems were investigated by solid-state (31)P and (13)C NMR spectroscopy. Using (31)P NMR, it was found that melittin-lipid bilayers form magnetically oriented elongated vesicles with the long axis parallel to the magnetic field above the liquid crystalline-gel phase transition temperature (T(m) = 24 degrees C). The conformation, orientation, and dynamics of melittin bound to the membrane were further determined by using this magnetically oriented lipid bilayer system. For this purpose, the (13)C NMR spectra of site-specifically (13)C-labeled melittin bound to the membrane in the static, fast magic angle spinning (MAS) and slow MAS conditions were measured. Subsequently, we analyzed the (13)C chemical shift tensors of carbonyl carbons in the peptide backbone under the conditions where they form an alpha-helix and reorient rapidly about the average helical axis. Finally, it was found that melittin adopts a transmembrane alpha-helix whose average axis is parallel to the bilayer normal. The kink angle between the N- and C-terminal helical rods of melittin in the lipid bilayer is approximately 140 degrees or approximately 160 degrees, which is larger than the value of 120 degrees determined by x-ray diffraction studies. Pore formation was clearly observed below the T(m) in the initial stage of lysis by microscope. This is considered to be caused by the association of melittin molecules in the lipid bilayer. PMID:10777736

  15. Changes in the compound classes of dissolved organic matter along an estuarine transect: A study using FTIR and 13C NMR

    NASA Astrophysics Data System (ADS)

    Abdulla, Hussain A. N.; Minor, Elizabeth C.; Dias, Robert F.; Hatcher, Patrick G.

    2010-07-01

    In this work, we use Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy ( 13C NMR) data to quantify the changes of major chemical compound classes (carboxylic acid, amide, ester, aliphatic, aromatic and carbohydrate) in high molecular weight (HMW, >1 kDa) dissolved organic matter (DOM) isolated along a transect through the Elizabeth River/Chesapeake Bay system to the coastal Atlantic Ocean off Virginia, USA. Results show that carboxylic acids and aromatic compounds are lost along the transect, while HMW DOC becomes enriched in carbohydrate moieties that could have a mid-transect source, perhaps the intensive red tide bloom ( Choclodinium polykrikoides) which occurred during our sampling period. Taking the second derivative of the FTIR spectra resolved three pools of de-protonated carboxylic acids at our Dismal Swamp site (used to represent terrestrial organic matter in this area): one carboxylic acid pool, complexed with iron, seems to be lost between the Dismal Swamp and river sites; the second appears biogeochemically active throughout the riverine transect, disappearing in the coastal ocean sample; the third seems refractory, with the potential to be transported to and to accumulate within the open ocean. Five-member ring esters (γ-lactones) were the major ester form in the Dismal Swamp; aliphatic and acetate esters were the dominant esters in the estuary/marine DOM. No amide groups were detectable in Dismal Swamp DOM; secondary amides were present at the estuarine/marine sites. Coupling FTIR with 13C NMR provides new insights into the biogeochemical roles of carboxylic acid, amide and ester compounds in aquatic ecosystems.

  16. Diagnosis of cerebral cryptococcoma using a computerized analysis of 1H NMR spectra in an animal model.

    PubMed

    Dzendrowskyj, Theresa E; Dolenko, Brion; Sorrell, Tania C; Somorjai, Rajmund L; Malik, Richard; Mountford, Carolyn E; Himmelreich, Uwe

    2005-06-01

    Viable cryptococci load in biopsy material from an animal model of cerebral cryptococcoma were correlated with 1H NMR spectra and metabolite profiles. A statistical classification strategy was applied to distinguish among high-resolution 1H NMR spectra acquired from cryptococcomas, glioblastomas, and normal brain tissue. The overall classification accuracy was 100% when a genetic-algorithm-based optimal region selection preceded the development of linear discriminant analysis-based classifiers. The method remained robust despite differences in the microbial load of the cryptococcoma group when harvested at different time points. These results indicate the feasibility of the method for diagnosis without isolation of the pathogenic microorganism and its potential for in vivo diagnosis based on computerized analysis of magnetic resonance spectra.

  17. The origin of molecular mobility during biomass pyrolysis as revealed by in situ (1)H NMR spectroscopy.

    PubMed

    Dufour, Anthony; Castro-Diaz, Miguel; Brosse, Nicolas; Bouroukba, Mohamed; Snape, Colin

    2012-07-01

    The thermochemical conversion of lignocellulosic biomass feedstocks offers an important potential route for the production of biofuels and value-added green chemicals. Pyrolysis is the first phenomenon involved in all biomass thermochemical processes and it controls to a major extent the product composition. The composition of pyrolysis products can be affected markedly by the extent of softening that occurs. In spite of extensive work on biomass pyrolysis, the development of fluidity during the pyrolysis of biomass has not been quantified. This paper provides the first experimental investigation of proton mobility during biomass pyrolysis by in situ (1)H NMR spectroscopy. The origin of mobility is discussed for cellulose, lignin and xylan. The effect of minerals on cellulose mobility is also investigated. Interactions between polymers in the native biomass network are revealed by in situ (1)H NMR analysis.

  18. A thorough study on the use of quantitative 1H NMR in Rioja red wine fermentation processes.

    PubMed

    López-Rituerto, Eva; Cabredo, Susana; López, Martina; Avenoza, Alberto; Busto, Jesús H; Peregrina, Jesús M

    2009-03-25

    In this study, we focused our attention on monitoring the levels of important metabolites of wine during the alcoholic and malolactic fermentation processes by quantitative nuclear magnetic resonance (qNMR). Therefore, using (1)H NMR, the method allows the simultaneous quantification of ethanol, acetic, malic, lactic, and succinic acids, and the amino acids proline and alanine, besides the ratio proline/arginine through fermentation of must of grapes corresponding to the Tempranillo variety. Each (1)H NMR spectrum gives direct and visual information concerning these metabolites, and the effectiveness of each process was assessed and compared by carrying out analyses using infrared spectroscopy to ethanol and acetic acid. The quantitative data were explained with the aid of chemometric algorithms.

  19. A study by (1)H NMR on the influence of some factors affecting lipid in vitro digestion.

    PubMed

    Nieva-Echevarría, Bárbara; Goicoechea, Encarnación; Manzanos, María J; Guillén, María D

    2016-11-15

    This article focuses on the impact of several experimental factors, including gastric acidification, intestinal transit time, presence of gastric lipase, sample/digestive fluids ratio, concentration and nature of the enzymes in intestinal juice, and bile concentration, on the extent of in vitro lipolysis when using a static model that simulates human digestion processes in mouth, stomach and small intestine. The study was carried out by Proton Nuclear Magnetic Resonance ((1)H NMR). This technique provides a complete molecular picture of lipolysis, evidencing for the first time, whether preferential hydrolysis of certain glycerides over others occurs. A lipolysis degree similar to that reported in vivo was reached by varying certain variables within a physiological range; among them, bile concentration was found to be crucial. The holistic view of this (1)H NMR study provides information of paramount importance to design sound in vitro digestion models to determine the bioaccessibility and bioavailability of lipophilic compounds.

  20. FT-IR and {sup 1}H NMR characterization of the products of an ethylene inverse diffusion flame

    SciTech Connect

    Santamaria, Alexander; Mondragon, Fanor; Molina, Alejandro; Marsh, Nathan D.; Eddings, Eric G.; Sarofim, Adel F.

    2006-07-15

    Knowledge of the chemical structure of young soot and its precursors is very useful in the understanding of the paths leading to soot particle inception. This paper presents analyses of the chemical functional groups, based on FT-IR and {sup 1}H NMR spectroscopy of the products obtained in an ethylene inverse diffusion flame. The trends in the data indicate that the soluble fraction of the soot becomes progressively more aromatic and less aliphatic as the height above the burner increases. Results from {sup 1}H NMR spectra of the chloroform-soluble soot samples taken at different heights above the burner corroborate the infrared results based on proton chemical shifts (Ha, H{alpha}, H{beta}, and H{gamma}). The results indicate that the aliphatic {beta} and {gamma} hydrogens suffered the most drastic reduction, while the aromatic character increased considerably with height, particularly in the first half of the flame. (author)

  1. Combination of 1H NMR and chemometrics to discriminate manuka honey from other floral honey types from Oceania.

    PubMed

    Spiteri, Marc; Rogers, Karyne M; Jamin, Eric; Thomas, Freddy; Guyader, Sophie; Lees, Michèle; Rutledge, Douglas N

    2017-02-15

    Manuka honey is a product produced essentially in New Zealand, and has been widely recognised for its antibacterial properties and specific taste. In this study, 264 honeys from New Zealand and Australia were analysed using proton NMR spectroscopy coupled with chemometrics. Known manuka markers, methylglyoxal and dihydroxyacetone, have been characterised and quantified, together with a new NMR marker, identified as being leptosperin. Manuka honey profiling using 1H NMR is shown to be a possible alternative to chromatography with the added advantage that it can measure methylglyoxal (MGO), dihydroxyacetone (DHA) and leptosperin simultaneously. By combining the information from these three markers, we established a model to estimate the proportion of manuka in a given honey. Markers of other botanical origins were also identified, which makes 1H NMR a convenient and efficient tool, complementary to pollen analysis, to control the botanical origin of Oceania honeys.

  2. Light induced E-Z isomerization in a multi-responsive organogel: elucidation from (1)H NMR spectroscopy.

    PubMed

    Mondal, Sanjoy; Chakraborty, Priyadarshi; Bairi, Partha; Chatterjee, Dhruba P; Nandi, Arun K

    2015-07-07

    A multiresponsive organogel of (E)-N'-(anthracene-10-ylmethylene)-3,4,5-tris(dodecyloxy)benzohydrazide (I) showed a decrease of fluorescence intensity, decrease in mechanical strength and a change in gel morphology on irradiation with a wavelength of 365 nm. This is attributed to the E-Z isomerization across the C=N bond of I as evidenced from (1)H NMR spectroscopy.

  3. Qualitative and quantitative analyses of Compound Danshen extract based on (1)H NMR method and its application for quality control.

    PubMed

    Yan, Kai-Jing; Chu, Yang; Huang, Jian-Hua; Jiang, Miao-Miao; Li, Wei; Wang, Yue-Fei; Huang, Hui-Yong; Qin, Yu-Hui; Ma, Xiao-Hui; Zhou, Shui-Ping; Sun, Henry; Wang, Wei

    2016-11-30

    In this study, a new approach using (1)H NMR spectroscopy combined with chemometrics method was developed for qualitative and quantitative analyses of extracts of Compound Danshen Dripping Pills (CDDP). For the qualitative analysis, some metabolites presented in Compound Danshen extract (CDE, extraction intermediate of CDDP) were detected, including phenolic acids, saponins, saccharides, organic acids and amino acids, by the proposed (1)H NMR method, and metabolites profiles were further analyzed by selected chemometrics algorithms to define the threshold values for product quality evaluation. Moreover, three main phenolic acids (danshensu, salvianolic acid B, and procatechuic aldehyde) in CDE were determined simultaneously, and method validation in terms of linearity, precision, repeatability, accuracy, and stability of the dissolved target compounds in solution was performed. The average recoveries varied between 84.20% and 110.75% while the RSDs were below 6.34% for the three phenolic acids. This (1)H NMR method offers an integral view of the extract composition, allows the qualitative and quantitative analysis of CDDP, and has the potential to be a supplementary tool to UPLC/HPLC for quality assessment of Chinese herbal medicines.

  4. Robust algorithms for automated chemical shift calibration of 1D 1H NMR spectra of blood serum.

    PubMed

    Pearce, Jake T M; Athersuch, Toby J; Ebbels, Timothy M D; Lindon, John C; Nicholson, Jeremy K; Keun, Hector C

    2008-09-15

    In biofluid NMR spectroscopy, the frequency of each resonance is typically calibrated by addition of a reference compound such as 3-(trimethylsilyl)-propionic acid- d 4 (TSP) to the sample. However biofluids such as serum cannot be referenced to TSP, due to shifts resonance caused by binding to macromolecules in solution. In order to overcome this limitation we have developed algorithms, based on analysis of derivative spectra, to locate and calibrate (1)H NMR spectra to the alpha-glucose anomeric doublet. We successfully used these algorithms to calibrate 77 serum (1)H NMR spectra and demonstrate the greater reproducibility of the calculated chemical-shift corrections ( r = 0.97) than those generated by manual alignment ( r = 0.8-0.88). Hence we show that these algorithms provide robust and reproducible methods of calibrating (1)H NMR of serum, plasma, or any biofluid in which glucose is abundant. Precise automated calibration of complex biofluid NMR spectra is an important tool in large-scale metabonomic or metabolomic studies, where hundreds or even thousands of spectra may be analyzed in high-resolution by pattern recognition analysis.

  5. Effect of organic matter application on CP-MAS-13C-NMR spectra of humic acids from a brown soil

    NASA Astrophysics Data System (ADS)

    Dou, S.

    2009-04-01

    The humified SOM or humic substances (HS) composed of humic acid (HA), fulvic acid (FA) and humin (HM) represent the most microbially recalcitrant and stable reservoir of organic carbon in soil (Piccolo et al., 2004). OM applications can influence the amount and structural characteristics of HS(Dou et al., 2008). During the past few decades, there has been much research on HS, but their chemical structure is still not fully understood (Dong, 2006).CP-MAS-13C-NMR spectroscopy was considered as an effective method to study structures of HS without dissolving problem compared with liquid 13C-NMR (Conte et al., 1997; Dou et al., 2008). It can directly measure the carbon framework and reflect the nature of HS transformation after OM application (Spaccini et al., 2000). For that reason, this method was applied in this study. The objective of this paper was to clarify the effect of long term OM application on the changes of structural characteristics in HAs, which provided new information for improving soil fertility by OM application. The experiment was carried out on a brown soil (Paleudalf in USDA Soil Taxonomy) at Shenyang Agricultural University, Liaoning province, China (N41°48'-E123°25'). The experiment included 3 treatments: zero-treatment (CKbr), and two pig manure (PM) treatments (O1 and O2) at the rates of 0.9 t ha-1 and 1.8 t ha-1 of organic carbon, respectively. The samples of the HA fraction were extracted, separated and purified according to the method described by Dou et al. (1991). Elemental composition, Differential thermal analysis (DTA), -lgK value, FT-IR and CP-MAS- 13C-NMR of HAs were performed. Effects on the contents of orgaic carbon and its composition. The contents of TOC were from 8.77 g kg-1 to 12.25 g kg-1. The relative contents in TOC for WSS, HA, and FA were 6.87%, 14.2% and 19.8%. Comparing the CKbr, the contents of WSS, HA and FA for O1 and O2 increased, but relative contents of WSS and FA decreased. The content of the HA increased after

  6. Hydrolysis is the dominating in vivo metabolism pathway for arctigenin: identification of novel metabolites of arctigenin by LC/MS/MS after oral administration in rats.

    PubMed

    Gao, Qiong; Zhang, Yufeng; Wo, Siukwan; Zuo, Zhong

    2013-04-01

    The phenylpropanoid dibenzylbutyrolactone lignan arctigenin, a key component found in Arctium lappa, or burdock, has been reported with a variety of therapeutic effects including anticancer, anti-inflammation, and antivirus effects. Using LC/MS/MS, three novel metabolites of arctigenin, namely, arctigenic acid, arctigenin-4-O'-glucuronide, and 4-O-demethylarctigenin were identified after oral administration of arctigenin in rats for the first time. Another potential metabolite of arctigenin, arctigenin-4'-O-sulfate, was identified in vitro but not in vivo. Structure of arctigenic acid, the major metabolite of arctigenin, was confirmed by 13C-NMR and 1H-NMR. Rapid hydrolysis in plasma was identified as the major metabolic pathway of arctigenin after its oral administration, with Vmax, Km, and Clint in rat plasma determined to be 2.21 ± 0.12 nmol/min/mg, 89.12 ± 9.44 µM, and 24.74 µL/min/mg, respectively. Paraoxonase 1 was further confirmed to be the enzyme responsible for arctigenin hydrolysis, with Vmax, Km, and Clint determined to be 55.39 ± 1.49 nmol/min/mg, 300.3 ± 10.86 µM, and 184.45 µL/min/mg, respectively.

  7. The 'Nuts and Bolts' of 13C NMR Spectroscopy at Elevated-Pressures and -Temperatures for Monitoring In Situ CO2 Conversion to Metal Carbonates

    NASA Astrophysics Data System (ADS)

    Moore, J. K.; Surface, J. A.; Skemer, P. A.; Conradi, M. S.; Hayes, S. E.

    2013-12-01

    We will present details of newly-constructed specialized NMR designed to conduct in situ elevated-pressure, elevated-temperature 13C NMR studies on unmixed slurries of minerals in the presence of CO2 or other gases. This static probe is capable of achieving 300 bar, 300C conditions, and it is designed to spectroscopically examine 13C signals in mixtures of solids, liquids, gases, and supercritical fluids. Ultimately, our aim is to monitor CO2 uptake in both ultramafic rocks and in more porous geological materials to understand the mechanisms of chemisorption as a function of temperature, pressure and pH. We will give details of the hardware setup, and we will show a variety of static in situ NMR, as well as ex situ 'magic-angle spinning' NMR to show the analyses that are possible of minerals in pure form and in mixtures. In addition, specific NMR pulse sequences, techniques, and modeling will be described in detail. In this in situ NMR probe, we are able to simulate processes at geologically relevant fluid pressures and temperatures, monitoring the kinetics of CO2 conversion to carbonates. The in situ NMR experiments consist of heterogeneous mixtures of rock, salty brine solution, and moderate pressure CO2 gas at elevated temperatures. The purpose of studying these reactions is to determine conditions that affect the efficacy of carbonate formation in various targeted geological reservoirs (i.e., peroditite, or others). Via 13C NMR, we have spectroscopically characterized and quantified the conversion of CO2 to magnesium carbonate and calcium carbonate minerals, including metastable intermediates (such as hydromagnesite, or dypingite in the case of magnesium carbonate species, or vaterite in the case of calcium carbonate species). Such species are distinguishable from a combination of the 13C isotropic chemical shift, the static 13C lineshape, and changes in spin-lattice (T1) relaxation times. We will demonstrate that NMR can be used for quantitative

  8. Soil Organic Matter Characterization by 13C-NMR and Thermal Analysis in Deep Tropical Soil Profiles from the Luquillo Critical Zone Observatory

    NASA Astrophysics Data System (ADS)

    Plante, A. F.; Hockaday, W. C.

    2015-12-01

    Tropical forest soils store large quantities of carbon (C) as soil organic matter (SOM), a substantial proportion of which is stored deep (> 30 cm) in the soil profile. Characterization of tropical SOM remains difficult, in part due to the analytical challenges associated high iron and low C concentrations. In this study, we combined solid-state 13C nuclear magnetic resonance (NMR) spectroscopy with analytical thermal analysis (differential scanning calorimetry, DSC; evolved CO2 gas analysis, CO2-EGA) to explore patterns in SOM composition in deep soil profiles from two contrasting soil types at the Luquillo Critical Zone Observatory (LCZO) in northeast Puerto Rico. Prior to 13C NMR, soils were repeatedly demineralized with hydrofluoric acid (HF) to remove paramagnetic compounds and concentrate organic matter. Given the scant information on tropical subsoil OM, we also sought to evaluate the effect of HF acid treatments on tropical subsoil SOM. HF treatments effectively enriched sample C and removed paramagnetic compounds, allowing us to obtain high-quality NMR spectra for low-C subsoils. C:N ratios before and after HF treatment were nearly identical (mean = 16.6 ± 0.8), suggesting that the SOM pool was not substantially fractionated, though C recoveries were low and variable. Thermal analyses confirmed the loss of a substantial fraction of the soil mineral matrix, however, retention of several endothermic regions in post-HF Inceptisol soils indicated that not all minerals were completely solubilized. In addition, important differences in the DSC and CO2-EGA thermograms were observed in comparing samples before versus after HF treatments. These results suggest that the organo-mineral associations were substantially altered, though it is not immediately clear the degree to which alterations in chemical composition versus binding association have changed. In addition to these qualitative changes, quantitative interpretations of 13C-NMR results from low-C and high

  9. High-Frequency (1)H NMR Chemical Shifts of Sn(II) and Pb(II) Hydrides Induced by Relativistic Effects: Quest for Pb(II) Hydrides.

    PubMed

    Vícha, Jan; Marek, Radek; Straka, Michal

    2016-10-17

    The role of relativistic effects on (1)H NMR chemical shifts of Sn(II) and Pb(II) hydrides is investigated by using fully relativistic DFT calculations. The stability of possible Pb(II) hydride isomers is studied together with their (1)H NMR chemical shifts, which are predicted in the high-frequency region, up to 90 ppm. These (1)H signals are dictated by sizable relativistic contributions due to spin-orbit coupling at the heavy atom and can be as large as 80 ppm for a hydrogen atom bound to Pb(II). Such high-frequency (1)H NMR chemical shifts of Pb(II) hydride resonances cannot be detected in the (1)H NMR spectra with standard experimental setup. Extended (1)H NMR spectral ranges are thus suggested for studies of Pb(II) compounds. Modulation of spin-orbit relativistic contribution to (1)H NMR chemical shift is found to be important also in the experimentally known Sn(II) hydrides. Because the (1)H NMR chemical shifts were found to be rather sensitive to the changes in the coordination sphere of the central metal in both Sn(II) and Pb(II) hydrides, their application for structural investigation is suggested.

  10. Stability and biodegradability of humic substances from Arctic soils of Western Siberia: insights from 13C-NMR spectroscopy and elemental analysis

    NASA Astrophysics Data System (ADS)

    Ejarque, E.; Abakumov, E.

    2015-11-01

    Arctic soils contain large amounts of organic matter which, globally, exceed the amount of carbon stored in vegetation biomass and in the atmosphere. Recent studies emphasize the potential sensitivity for this soil organic matter (SOM) to be mineralised when faced with increasing ambient temperatures. In order to better refine the predictions about the response of SOM to climate warming, there is a need to increase the spatial coverage of empirical data on SOM quantity and quality in the Arctic area. This study provides, for the first time, a characterisation of SOM from the Gydan Peninsula in the Yamal Region, Western Siberia, Russia. On the one hand, soil humic acids and their humification state were characterised by measuring the elemental composition and diversity of functional groups using solid-state 13C-NMR spectroscopy. Also, the total mineralisable carbon was measured. Our results show that there is a uniformity of SOM characteristics throughout the studied region, as well as within soil profiles. Such in-depth homogeneity, together with a predominance of aliphatic carbon structures, suggests the accumulation in soil of raw and slightly decomposed organic matter. Moreover, results on total mineralisable carbon suggest a high lability of these compounds. The mineralisation rate was found to be independent of SOM quality, and to be mainly explained solely by the total carbon content. Overall, our results provide further evidence on the fundamental role that the soils of Western Siberia may have on regulating the global carbon balance when faced with increasing ambient temperatures.

  11. Construction and 13C NMR signal-amplification efficiency of a dynamic nuclear polarizer at 6.4 T and 1.4 K

    NASA Astrophysics Data System (ADS)

    Kiswandhi, Andhika; Niedbalski, Peter; Parish, Christopher; Ferguson, Sarah; Taylor, David; McDonald, George; Lumata, Lloyd

    Dissolution dynamic nuclear polarization (DNP) is a rapidly emerging technique in biomedical and metabolic imaging since it amplifies the liquid-state nuclear magnetic resonance (NMR) and imaging (MRI) signals by >10,000-fold. Originally used in nuclear scattering experiments, DNP works by creating a non-Boltzmann nuclear spin distribution by transferring the high electron (γ = 28,000 MHz/T) thermal polarization to the nuclear spins via microwave irradiation of the sample at high magnetic field and low temperature. A dissolution device is used to rapidly dissolve the frozen sample and consequently produces an injectable ``hyperpolarized'' liquid at physiologically-tolerable temperature. Here we report the construction and performance evaluation of a dissolution DNP hyperpolarizer at 6.4 T and 1.4 K using a continuous-flow cryostat. The solid and liquid-state 13C NMR signal enhancement levels of 13C acetate samples doped with trityl OX063 and 4-oxo-TEMPO free radicals will be discussed and compared with the results from the 3.35 T commercial hyperpolarizer. This work is supported by US Dept of Defense Award No. W81XWH-14-1-0048 and Robert A. Welch Foundation Grant No. AT-1877.

  12. Application of /sup 13/C NMR, fluorescence, and light-scattering techniques for structural studies of oil-in-water microemulsions

    SciTech Connect

    Tricot, Y.; Kiwi, J.; Niederberger, W.; Graetzel, M.

    1981-04-02

    The nature of the microdroplets present in oil-in-water microemulsions was examined by using the 4-component model system water-hexadecane-sodium hexadecyl sulfate-pentanol. Three compositions were selected corresponding to regions in the pahse diagram where the content of water, cosurfactant, and oil, respectively, approached the tolerable limit to yield clear isotropic solutions. In the water-side microemulsion, the radius of the droplets is 127A as determined from quasi-elastic light-scattering measurements. Fluorescence experiments showed that the core of the microspheres has a microviscosity similar to hexadecane at room temperature. /sup 13/C NMR shift analysis was applied to test the partitioning of cosurfactant between the surface and the interior of the droplet. For all three compositions significant fractions of the cosurfactant are present in the interior. This is corroborated by results obtained from T/sub 1/ relaxation-time analysis at different field strengths. The influence of the field strength on T/sub 1/ is explained in terms of a model based on a distribution of correlation times. In particular, the importance of taking into account slower rotational modes such as the tumbling of the whole microsphere is illustrated.

  13. Early estrogen-induced metabolic changes and their inhibition by actinomycin D and cycloheximide in human breast cancer cells: sup 31 P and sup 13 C NMR studies

    SciTech Connect

    Neeman, M.; Degani, H. )

    1989-07-01

    Metabolic changes following estrogen stimulation and the inhibition of these changes in the presence of actinomycin D and cycloheximide were monitored continuously in perfused human breast cancer T47D clone 11 cells with {sup 31}P and {sup 13}C NMR techniques. The experiments were performed by estrogen rescue of tamoxifen-treated cells. Immediately after perfusion with estrogen-containing medium, a continuous enhancement in the rates of glucose consumption, lactate production by glycolysis, and glutamate synthesis by the Krebs cycle occurred with a persistent 2-fold increase at 4 hr. Pretreatment with either actinomycin D or cycloheximide, at concentrations known to inhibit mRNA and protein synthesis, respectively, and simultaneous treatment with estrogen and each inhibitor prevented the estrogen-induced changes in glucose metabolism. This suggested that the observed estrogen stimulation required synthesis of mRNA and protein. These inhibitors also modulated several metabolic activities that were not related to estrogen stimulation. The observed changes in the in vivo kinetics of glucose metabolism may provide a means for the early detection of the response of human breast cancer cells to estrogen versus tamoxifen treatment.

  14. High-resolution sup 13 C NMR study of the topography and dynamics of methionine residues in detergent-solubilized bacteriorhodopsin

    SciTech Connect

    Seigneuret, M.; Neumann, J.M.; Levy, D.; Rigaud, J.L. )

    1991-04-23

    The proton transport membrane protein bacteriorhodopsin has been biosynthetically labeled with (methyl-{sup 13}C)methionine and studied by high-resolution {sup 13}C NMR after solubilization in the detergent Triton X-100. The nine methionine residues of bacteriorhodopsin give rise to four well-resolved {sup 13}C resonances, two of which are shifted upfield or downfield due to nearby aromatic residues. Methionine residues located on the hydrophilic surfaces, on the hydrophobic surface, and in the interior of the protein could be discriminated by studying the effects of papain proteolysis, glycerol-induced viscosity increase, and paramagnetic broadening by spin-labels on NMR spectra. Such data were used to evaluate current models of the bacteriorhodopsin transmembrane folding and tertiary structure. T{sub 2} and NOE measurements were performed to study the local dynamics of methionine residues in bacteriorhodopsin. For the detergent-solubilized protein, hydrophilic and hydrophobic external residues undergo a relatively large extent of side chain wobbling motion while most internal residues are less mobile. In the native purple membrane and in reconstituted bacteriorhodopsin liposomes, almost all methionine residues have their wobbling motion severely restricted, indicating a large effect of the membrane environment on the protein internal dynamics.

  15. Comprehensive quantum chemical and spectroscopic (FTIR, FT-Raman, 1H, 13C NMR) investigations of O-desmethyltramadol hydrochloride an active metabolite in tramadol - An analgesic drug

    NASA Astrophysics Data System (ADS)

    Arjunan, V.; Santhanam, R.; Marchewka, M. K.; Mohan, S.

    2014-03-01

    O-desmethyltramadol is one of the main metabolites of tramadol widely used clinically and has analgesic activity. The FTIR and FT-Raman spectra of O-desmethyl tramadol hydrochloride are recorded in the solid phase in the regions 4000-400 cm-1 and 4000-100 cm-1, respectively. The observed fundamentals are assigned to different normal modes of vibration. Theoretical studies have been performed as its hydrochloride salt. The structure of the compound has been optimised with B3LYP method using 6-31G** and cc-pVDZ basis sets. The optimised bond length and bond angles are correlated with the X-ray data. The experimental wavenumbers were compared with the scaled vibrational frequencies determined by DFT methods. The IR and Raman intensities are determined with B3LYP method using cc-pVDZ and 6-31G(d,p) basic sets. The total electron density and molecular electrostatic potential surfaces of the molecule are constructed by using B3LYP/cc-pVDZ method to display electrostatic potential (electron + nuclei) distribution. The electronic properties HOMO and LUMO energies were measured. Natural bond orbital analysis of O-desmethyltramadol hydrochloride has been performed to indicate the presence of intramolecular charge transfer. The 1H and 13C NMR chemical shifts of the molecule have been anlysed.

  16. Rapid adaptation of rat brain and liver metabolism to a ketogenic diet: an integrated study using (1)H- and (13)C-NMR spectroscopy.

    PubMed

    Roy, Maggie; Beauvieux, Marie-Christine; Naulin, Jérôme; El Hamrani, Dounia; Gallis, Jean-Louis; Cunnane, Stephen C; Bouzier-Sore, Anne-Karine

    2015-07-01

    The ketogenic diet (KD) is an effective alternative treatment for refractory epilepsy in children, but the mechanisms by which it reduces seizures are poorly understood. To investigate how the KD modifies brain metabolism, we infused control (CT) and 7-day KD rats with either [1-(13)C]glucose (Glc) or [2,4-(13)C2]β-hydroxybutyrate (β-HB). Specific enrichments of amino acids (AAs) measured by (1)H- and (13)C-NMR in total brain perchloric acid extracts were similar between CT and KD rats after [1-(13)C]Glc infusion whereas they were higher in KD rats after [2,4-(13)C2]β-HB infusion. This suggests better metabolic efficiency of ketone body utilization on the KD. The relative rapid metabolic adaptation to the KD included (1) 11%-higher brain γ-amino butyric acid (GABA)/glutamate (Glu) ratio versus CT, (2) liver accumulation of the ketogenic branched-chain AAs (BCAAs) leucine (Leu) and isoleucine (ILeu), which were never detected in CT, and (3) higher brain Leu and ILeu contents. Since Glu and GABA are excitatory and inhibitory neurotransmitters, respectively, higher brain GABA/Glu ratio could contribute to the mechanism by which the KD reduces seizures in epilepsy. Increased BCAA on the KD may also contribute to better seizure control.

  17. Calculation of the {sup 13}C NMR chemical shift of ether linkages in lignin derived geopolymers: Constraints on the preservation of lignin primary structure with diagenesis

    SciTech Connect

    Cody, G.D.; Saghi-Szabo, G.

    1999-01-01

    Methodology for the calculation of {sup 13}C NMR shielding on molecular organic fragments, representative of monomers in a type 3 kerogen, is presented. Geometry optimization of each molecular fragment was carried out using Density Functional Theory employing the generalized gradient approximation. NMR shieldings were calculated using the Individual Gauge for Localized orbital Method. Convincing agreement was obtained between calculated and experimentally derived isotropic chemical shielding values over a broad frequency range. Shielding calculations employing the localized orbitals/local origin method resulted in nearly identical results. NMR chemical shift static powder patterns also exhibit excellent agreement with experimental values. These quantum mechanical calculations were applied to determine the extent of lignin primary structure preservation with diagenesis. Specifically, the calculations were used to assess whether inhomogeneous spectral broadening due to both functional group variation and local configurational variability may inhibit the detection of otherwise significant quantities of alkyl-aryl ethers in lignin derived geopolymers. Determination of the chemical-shielding tensor principle axis values reveals a strong correlation between anisotropy and asymmetry with local configuration effects such as dihedral rotation, phenyl group rotation, and bond angle variation. These results indicate that a range of 9 ppm in the isotropic chemical shift can be ascribed to local configuration. Consequently, an upper limit of 5% alkyl-aryl-linkages may go undetected using NMR spectroscopy on lignin-derived geopolymers at the liginite-sub-bituminous transition. It is concluded that the primary structure of lignin does not persist in kerogens even at relatively low thermal maturities.

  18. Calculation of the 13C NMR chemical shift of ether linkages in lignin derived geopolymers: . Constraints on the preservation of lignin primary structure with diagenesis

    NASA Astrophysics Data System (ADS)

    Cody, G. D.; Sághi-Szabó, G.

    1999-01-01

    Methodology for the calculation of 13C NMR shieldings on molecular organic fragments, representative of monomers in a type III kerogen, is presented. Geometry optimization of each molecular fragment was carried out using Density Functional Theory employing the generalized gradient approximation. NMR shieldings were calculated using the Individual Gauge for Localized Orbital Method. Convincing agreement was obtained between calculated and experimentally derived isotropic chemical shielding values over a broad frequency range. Shielding calculations employing the localized orbitals/local origin method resulted in nearly identical results. NMR chemical shift static powder patterns also exhibit excellent agreement with experimental values. These quantum mechanical calculations were applied to determine the extent of lignin primary structure preservation with diagenesis. Specifically, the calculations were used to assess whether inhomogeneous spectral broadening due to both functional group variation and local configurational variability may inhibit the detection of otherwise significant quantities of alkyl-aryl ethers in lignin derived geopolymers. Determination of the chemical-shielding tensor principle axis values reveals a strong correlation between anisotropy and asymmetry with local configuration effects such as dihedral rotation, phenyl group rotation, and bond angle variation. These results indicate that a range of 9 ppm in the isotropic chemical shift can be ascribed to local configuration. Consequently, an upper limit of 5% alkyl-aryl-linkages may go undetected using NMR spectroscopy on lignin-derived geopolymers at the liginite-sub-bituminous transition. It is concluded that the primary structure of lignin does not persist in kerogens even at relatively low thermal maturities.

  19. 13C NMR quantification of mono and diacylglycerols obtained through the solvent-free lipase-catalyzed esterification of saturated fatty acids.

    PubMed

    Fernandes, Jane Luiza Nogueira; de Souza, Rodrigo Octavio Mendonça Alves; de Vasconcellos Azeredo, Rodrigo Bagueira

    2012-06-01

    In the present investigation, we studied the enzymatic synthesis of monoacylglycerols (MAG) and diacylglycerols (DAG) via the esterification of saturated fatty acids (stearic, palmitic and an industrial residue containing 87% palmitic acid) and glycerol in a solvent-free system. Three immobilized lipases (Lipozyme RM IM, Lipozyme TL IM and Novozym 435) and different reaction conditions were evaluated. Under the optimal reaction conditions, esterifications catalyzed by Lipozyme RM IM resulted in a mixture of MAG and DAG at high conversion rates for all of the substrates. In addition, except for the reaction of industrial residue at atmospheric pressure, all of these products met the World Health Organization and European Union directives for acylglycerol mixtures for use in food applications. The products were quantified by (13)C NMR, with the aid of an external reference signal which was generated from a sealed coaxial tube filled with acetonitrile-d3. After calibrating the area of this signal using the classical external reference method, the same coaxial tube was used repeatedly to quantify the reaction products.

  20. Solid-state and solution /sup 13/C NMR in the conformational analysis of methadone-hydrochloride and related narcotic analgesics

    SciTech Connect

    Sumner, S.C.J.

    1986-01-01

    Solid state and solution /sup 13/C NMR have been used to study the conformations of the racemic mixtures and single enantiomers of methadone hydrochloride, alpha and beta methadol hydrochloride, and alpha and beta acetylmethadol hydrochloride. The NMR spectra acquired for the compounds as solids, and in polar and nonpolar solvents are compared, in order to determine the conformation of the molecules in solution. To determine the reliability of assigning solution conformations by comparing solution and solid state chemical shift data, three bond coupling constants measured in solution are compared with those calculated from X-ray data. The conformations of the racemic mixture and plus enantiomer of methadone hydrochloride have been shown to be very similar in the solid state, where minor differences in conformation can be seen by comparing NMR spectra obtained for the solids. Also shown is that the molecules of methadone hydrochloride have conformations in polar and in nonpolar solvents which are very similar to the conformation of the molecules in the solid state.

  1. Stability and biodegradability of organic matter from Arctic soils of Western Siberia: Insights from 13C-NMR spectroscopy and elemental analysis

    NASA Astrophysics Data System (ADS)

    Ejarque, Elisabet; Abakumov, Evgeny

    2016-04-01

    Arctic soils contain large amounts of organic matter which, globally, exceed the amount of carbon stored in vegetation biomass and in the atmosphere. Recent studies emphasize the potential sensitivity for this soil organic matter (SOM) to be mineralised when faced with increasing ambient temperatures. In order to better refine the predictions about the response of SOM to climate warming, there is a need to increase the spatial coverage of empirical data on SOM quantity and quality in the Arctic area. This study provides, for the first time, a characterisation of SOM from the Gydan Peninsula in the Yamal Region, Western Siberia, Russia. On the one hand, soil humic acids and their humification state were characterised by measuring the elemental composition and diversity of functional groups using solid-state 13C-NMR spectroscopy. Also, the total mineralisable carbon was measured. Our results show that there is a predominance of aliphatic carbon structures, with a distribution of functional groups that has a minimal variation both regionally and within soil depth. Such vertical homogeneity and low level of aromaticity reflects the accumulation in soil of lowly decomposed organic matter due to cold temperatures. Mineralisation rates were found to be independent of SOM quality, and to be mainly explained solely by the total carbon content. Overall, our results provide further evidence on the sensitivity that the soils of Western Siberia may have to increasing ambient temperatures and highlight the important role that this region can play in the global carbon balance under the effects of climate warming.

  2. In Situ Solid-State (13)C NMR Observation of Pore Mouth Catalysis in Etherification of β-Citronellene with Ethanol on Zeolite Beta.

    PubMed

    Radhakrishnan, Sambhu; Goossens, Pieter-Jan; Magusin, Pieter C M M; Sree, Sreeprasanth Pulinthanathu; Detavernier, Christophe; Breynaert, Eric; Martineau, Charlotte; Taulelle, Francis; Martens, Johan A

    2016-03-02

    The reaction mechanism of etherification of β-citronellene with ethanol in liquid phase over acid zeolite beta is revealed by in situ solid-state (13)C NMR spectroscopy. Comparison of (13)C Hahn-echo and (1)H-(13)C cross-polarization NMR characteristics is used to discriminate between molecules freely moving in liquid phase outside the zeolite and molecules adsorbed inside zeolite pores and in pore mouths. In the absence of ethanol, β-citronellene molecules enter zeolite pores and react to isomers. In the presence of ethanol, the concentration of β-citronellene inside zeolite pores is very low because of preferential adsorption of ethanol. The etherification reaction proceeds by adsorption of β-citronellene molecule from the external liquid phase in a pore opening where it reacts with ethanol from inside the pore. By competitive adsorption, ethanol prevents the undesired side reaction of β-citronellene isomerization inside zeolite pores. β-citronellene etherification on zeolite beta is suppressed by bulky base molecules (2,4,6-collidine and 2,6-ditertiarybutylpyridine) that do not enter the zeolite pores confirming the involvement of easily accessible acid sites in pore openings. The use of in situ solid-state NMR to probe the transition from intracrystalline catalysis to pore mouth catalysis depending on reaction conditions is demonstrated for the first time. The study further highlights the potential of this NMR approach for investigations of adsorption of multicomponent mixtures in general.

  3. Rapid adaptation of rat brain and liver metabolism to a ketogenic diet: an integrated study using 1H- and 13C-NMR spectroscopy

    PubMed Central

    Roy, Maggie; Beauvieux, Marie-Christine; Naulin, Jérôme; El Hamrani, Dounia; Gallis, Jean-Louis; Cunnane, Stephen C; Bouzier-Sore, Anne-Karine

    2015-01-01

    The ketogenic diet (KD) is an effective alternative treatment for refractory epilepsy in children, but the mechanisms by which it reduces seizures are poorly understood. To investigate how the KD modifies brain metabolism, we infused control (CT) and 7-day KD rats with either [1-13C]glucose (Glc) or [2,4-13C2]β-hydroxybutyrate (β-HB). Specific enrichments of amino acids (AAs) measured by 1H- and 13C-NMR in total brain perchloric acid extracts were similar between CT and KD rats after [1-13C]Glc infusion whereas they were higher in KD rats after [2,4-13C2]β-HB infusion. This suggests better metabolic efficiency of ketone body utilization on the KD. The relative rapid metabolic adaptation to the KD included (1) 11%-higher brain γ-amino butyric acid (GABA)/glutamate (Glu) ratio versus CT, (2) liver accumulation of the ketogenic branched-chain AAs (BCAAs) leucine (Leu) and isoleucine (ILeu), which were never detected in CT, and (3) higher brain Leu and ILeu contents. Since Glu and GABA are excitatory and inhibitory neurotransmitters, respectively, higher brain GABA/Glu ratio could contribute to the mechanism by which the KD reduces seizures in epilepsy. Increased BCAA on the KD may also contribute to better seizure control. PMID:25785828

  4. 13C-NMR Assessment of the Pattern of Organic Matter Transformation during Domestic Wastewater Treatment by Autothermal Aerobic Digestion (ATAD)

    PubMed Central

    Piterina, Anna V.; Barlett, John; Pembroke, J. Tony

    2009-01-01

    The pattern of biodegradation and the chemical changes occurring in the macromolecular fraction of domestic sludge during autothermal thermophilic aerobic digestion (ATAD) was monitored and characterised via solid-state 13C-NMR CP-MAS. Major indexes such as aromaticity, hydrophobicity and alkyl/O-alkyl ratios calculated for the ATAD processed biosolids were compared by means of these values to corresponding indexes reported for sludges of different origin such as manures, soil organic matter and certain types of compost. Given that this is the first time that these techniques have been applied to ATAD sludge, the data indicates that long-chain aliphatics are easily utilized by the microbial populations as substrates for metabolic activities at all stages of aerobic digestion and serve as a key substrate for the temperature increase, which in turn results in sludge sterilization. The ATAD biosolids following treatment had a prevalence of O-alkyl domains, a low aromaticity index (10.4%) and an alkyl/O-alkyl ratio of 0.48 while the hydrophobicity index of the sludge decreased from 1.12 to 0.62 during the treatment. These results have important implications for the evolution of new ATAD modalities particularly in relation to dewatering and the future use of ATAD processed biosolids as a fertilizer, particularly with respect to hydrological impacts on the soil behaviour. PMID:19742161

  5. 1H NMR assignments of apo calcyclin and comparative structural analysis with calbindin D9k and S100 beta.

    PubMed Central

    Potts, B. C.; Carlström, G.; Okazaki, K.; Hidaka, H.; Chazin, W. J.

    1996-01-01

    The homodimeric S100 protein calcyclin has been studied in the apo state by two-dimensional 1H NMR spectroscopy. Using a combination of scalar correlation and NOE experiments, sequence-specific 1H NMR assignments were obtained for all but one backbone and > 90% of the side-chain resonances. To our knowledge, the 2 x 90 residue (20 kDa) calcyclin dimer is the largest protein system for which such complete assignments have been made by purely homonuclear methods. Sequential and medium-range NOEs and slowly exchanging backbone amide protons identified directly the four helices and the short antiparallel beta-type interaction between the two binding loops that comprise each subunit of the dimer. Further analysis of NOEs enabled the unambiguous assignment of 556 intrasubunit distance constraints, 24 intrasubunit hydrogen bonding constraints, and 2 x 26 intersubunit distance constraints. The conformation of the monomer subunit was refined by distance geometry and restrained molecular dynamics calculations using the intrasubunit constraints only. Calculation of the dimer structure starting from this conformational ensemble has been reported elsewhere. The extent of structural homology among the apo calcyclin subunit, the monomer subunit of apo S100 beta, and monomeric apo calbindin D9k has been examined in detail by comparing 1H NMR chemical shifts and secondary structures. This analysis was extended to a comprehensive comparison of the three-dimensional structures of the calcyclin monomer subunit and calbindin D9k, which revealed greater similarity in the packing of their hydrophobic cores than was anticipated previously. Together, these results support the hypothesis that all members of the S100 family have similar core structures and similar modes of dimerization. Analysis of the amphiphilicity of Helix IV is used to explain why calbindin D9k is monomeric, but full-length S100 proteins form homodimers. PMID:8931135

  6. Studies of Secondary Melanoma on C57BL/6J Mouse Liver Using 1H NMR Metabolomics

    SciTech Connect

    Feng, Ju; Isern, Nancy G.; Burton, Sarah D.; Hu, Jian Z.

    2013-10-31

    NMR metabolomics, consisting of solid state high resolution (hr) magic angle spinning (MAS) 1H NMR (1H hr-MAS), liquid state high resolution 1H-NMR, and principal components analysis (PCA) has been used to study secondary metastatic B16-F10 melanoma in C57BL/6J mouse liver . The melanoma group can be differentiated from its control group by PCA analysis of the absolute concentrations or by the absolute peak intensities of metabolites from either 1H hr-MAS NMR data on intact liver tissues or liquid state 1H-NMR spectra on liver tissue extracts. In particular, we found that the absolute concentrations of alanine, glutamate, creatine, creatinine, fumarate and cholesterol are elevated in the melanoma group as compared to controls, while the absolute concentrations of succinate, glycine, glucose, and the family of linear lipids including long chain fatty acids, total choline and acylglycerol are decreased. The ratio of glycerophosphocholine to phosphocholine is increased by about 1.5 fold in the melanoma group, while the absolute concentration of total choline is actually lower in melanoma mice. These results suggest the following picture in secondary melanoma metastasis: Linear lipid levels are decreased by beta oxidation in the melanoma group, which contributes to an increase in the synthesis of cholesterol, and also provides an energy source input for TCA cycle. These findings suggest a link between lipid oxidation, the TCA cycle and the hypoxia-inducible factors (HIF) signal pathway in tumor metastases. Thus this study indicates that the metabolic profile derived from NMR analysis can provide a valuable bio-signature of malignancy and cell hypoxia in metastatic melanoma.

  7. Conformation of some N,N'-arylalkyl thioureas by 1H-NMR and infrared spectral analysis

    NASA Astrophysics Data System (ADS)

    Sudha, L. V.; Sathyanarayana, D. N.

    Several N,N'-arylalkyl thioureas were examined with 1H-NMR and i.r. spectra in order to study the conformation of the -NHCSNH- group. The influence of temperature and substituents on the chemical shift of the NH protons has been investigated. Formation of a strong intramolecular hydrogen bond stabilizes the trans—cis conformation for most systems, while for the others the prevalence of different rotational isomers can be postulated. The influence of the steric effect on hydrogen bonding and molecular conformation is discussed.

  8. Hydrogen cluster/network in tobermorite as studied by multiple-quantum spin counting {sup 1}H NMR

    SciTech Connect

    Mogami, Yuuki; Yamazaki, Satoru; Matsuno, Shinya; Matsui, Kunio; Noda, Yasuto; Takegoshi, K.

    2014-12-15

    Proton multiple-quantum (MQ) spin-counting experiment has been employed to study arrangement of hydrogen atoms in 9 Å/11 Å natural/synthetic tobermorites. Even though all tobermorite samples give similar characterless, broad static-powder {sup 1}H NMR spectra, their MQ spin-counting spectra are markedly different; higher quanta in 11 Å tobermorite do not grow with the MQ excitation time, while those in 9 Å one do. A statistical analysis of the MQ results recently proposed [26] is applied to show that hydrogens align in 9 Å tobermorite one dimensionally, while in 11 Å tobermorite they exist as a cluster of 5–8 hydrogen atoms.

  9. 31P{1H}NMR and carbonyl force constants of unsymmetrical bidentate phosphine complexes of group (VI) metal carbonyls

    NASA Astrophysics Data System (ADS)

    Jesu Raj, Joe Gerald; Pathak, Devendra Deo; Kapoor, Pramesh N.

    2015-05-01

    In our present work we report synthesis of an unsymmetrical diphos ligand, 1-diphenylphosphino-2-di-m-tolylphosphinoethane and its coordinate complexes with group (VI) metal carbonyls such as Cr(CO)6 Mo(CO)6 and W(CO)6. The synthesized ligand and its complexes have been completely characterized by elemental analyses, FTIR, 1HNMR, 31P{1H}NMR and FAB mass spectrometry methods. Special emphasis has been given to calculations of carbonyl force constants. Based on the spectroscopic evidences it has been confirmed that these metal carbonyl complexes with the ditertiary phosphine ligand showed cis geometry in their molecular structure.

  10. Using solid 13C NMR coupled with solution 31P NMR spectroscopy to investigate molecular species and lability of organic carbon and phosphorus from aquatic plants in Tai Lake, China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aquatic plants are involved in the storage and release capacity for organic matter and nutrients. In this study, solid 13C and solution 31P nuclear magnetic resonance (NMR) spectroscopy were used to characterize the biomass samples of six aquatic plants. Solid 13C NMR spectroscopy revealed the domin...

  11. Ab initio/GIAO-CCSD(T) (13)C NMR study of the rearrangement and dynamic aspects of rapidly equilibrating tertiary carbocations, C6H13(+) and C7H15(+).

    PubMed

    Olah, George A; Prakash, G K Surya; Rasul, Golam

    2016-01-05

    The rearrangement pathways of the equilibrating tertiary carbocations, 2,3-dimethyl-2-butyl cation (C6H13(+), 1), 2,3,3-trimethyl-2-butyl cation (C7H15(+), 5) and 2,3-dimethyl-2-pentyl cation (C7H15(+), 8 and 9) were investigated using the ab initio/GIAO-CCSD(T) (13)C NMR method. Comparing the calculated and experimental (13)C NMR chemical shifts of a series of carbocations indicates that excellent prediction of δ(13)C could be achieved through scaling. In the case of symmetrical equilibrating cations (1 and 5) the Wagner-Meerwein 1,2-hydride and 1,2-methide shifts, respectively, produce the same structure. This indicates that the overall (13)C NMR chemical shifts are conserved and independent of temperature. However, in the case of unsymmetrical equilibrating cations (8 and 9) the Wagner-Meerwein shift produces different tertiary structures, which have slightly different thermodynamic stabilities and, thus, different spectra. At the MP4(SDTQ)/cc-pVTZ//MP2/cc-pVTZ + ZPE level structure 8 is only 90 calories/mol more stable than structure 9. Based on computed (13)C NMR chemical shift calculations, mole fractions of these isomers were determined by assuming the observed chemical shifts are due to the weighted average of the chemical shifts of the static ions.

  12. Regio-selective detection of dynamic structure of transmembrane alpha-helices as revealed from (13)C NMR spectra of [3-13C]Ala-labeled bacteriorhodopsin in the presence of Mn2+ ion.

    PubMed

    Tuzi, S; Hasegawa, J; Kawaminami, R; Naito, A; Saitô, H

    2001-07-01

    13C Nuclear magnetic resonance (NMR) spectra of [3-(13)C]Ala-labeled bacteriorhodopsin (bR) were edited to give rise to regio-selective signals from hydrophobic transmembrane alpha-helices by using NMR relaxation reagent, Mn(2+) ion. As a result of selective suppression of (13)C NMR signals from the surfaces in the presence of Mn(2+) ions, several (13)C NMR signals of Ala residues in the transmembrane alpha-helices were identified on the basis of site-directed mutagenesis without overlaps from (13)C NMR signals of residues located near the bilayer surfaces. The upper bound of the interatomic distances between (13)C nucleus in bR and Mn(2+) ions bound to the hydrophilic surface to cause suppressed peaks by the presence of Mn(2+) ion was estimated as 8.7 A to result in the signal broadening to 100 Hz and consistent with the data based on experimental finding. The Ala C(beta) (13)C NMR peaks corresponding to Ala-51, Ala-53, Ala-81, Ala-84, and Ala-215 located around the extracellular half of the proton channel and Ala-184 located at the kink in the helix F were successfully identified on the basis of (13)C NMR spectra of bR in the presence of Mn(2+) ion and site-directed replacement of Ala by Gly or Val. Utilizing these peaks as probes to observe local structure in the transmembrane alpha-helices, dynamic conformation of the extracellular half of bR at ambient temperature was examined, and the local structures of Ala-215 and 184 were compared with those elucidated at low temperature. Conformational changes in the transmembrane alpha-helices induced in D85N and E204Q and its long-range transmission from the proton release site to the site around the Schiff base in E204Q were also examined.

  13. Chiral trimethylsilylated C2-symmetrical diamines as phosphorous derivatizing agents for the determination of the enantiomeric excess of chiral alcohols by 1H NMR

    PubMed Central

    Chauvin, Anne-Sophie; Alexakis, Alexandre

    2006-01-01

    The use of organophosphorus derivatising agents, prepared from C2 symmetric trimethylsilylated diamines, for the 1H NMR and 31P NMR determination of the enantiomeric composition of chiral alcohols is described. PMID:16566844

  14. Urea's effect on the ribonuclease A catalytic efficiency: a kinetic, 1H NMR and molecular orbital study.

    PubMed

    Almarza, Jorge; Rincón, Luis; Bahsas, Alí; Pinto, María Angela; Brito, Francisco

    2013-02-01

    Understanding of protein-urea interactions is one of the greatest challenges to modern structural protein chemistry. Based in enzyme kinetics experiments and (1)H NMR spectroscopic analysis we proposed that urea, at low concentrations, directly interacts with the protonated histidines of the active center of RNase A, following a simple model of competitive inhibition. These results were supported by theoretical analysis based on the frontier molecular orbital theory and suggest that urea might establish a favorable interaction with the cationic amino acids. Our experimental evidence and theoretical analysis indicate that the initials steps of the molecular mechanism of Urea-RNase A interaction passes through the establishment of a three center four electron adduct. Also, our results would explain the observed disruption of the (1)H NMR signals corresponding to H12 and H119 (involved in catalysis) of the RNase A studied in the presence of urea. Our interaction model of urea-amino acids (cationic) can be extended to explain the inactivation of other enzymes with cationic amino acids at the active site.

  15. Molecular characterization of dissolved organic matter in glacial ice: coupling natural abundance 1H NMR and fluorescence spectroscopy.

    PubMed

    Pautler, Brent G; Woods, Gwen C; Dubnick, Ashley; Simpson, André J; Sharp, Martin J; Fitzsimons, Sean J; Simpson, Myrna J

    2012-04-03

    Glaciers and ice sheets are the second largest freshwater reservoir in the global hydrologic cycle, and the onset of global climate warming has necessitated an assessment of their contributions to sea-level rise and the potential release of nutrients to nearby aquatic environments. In particular, the release of dissolved organic matter (DOM) from glacier melt could stimulate microbial activity in both glacial ecosystems and adjacent watersheds, but this would largely depend on the composition of the material released. Using fluorescence and (1)H NMR spectroscopy, we characterize DOM at its natural abundance in unaltered samples from a number of glaciers that differ in geographic location, thermal regime, and sample depth. Parallel factor analysis (PARAFAC) modeling of DOM fluorophores identifies components in the ice that are predominantly proteinaceous in character, while (1)H NMR spectroscopy reveals a mixture of small molecules that likely originate from native microbes. Spectrofluorescence also reveals a terrestrial contribution that was below the detection limits of NMR; however, (1)H nuclei from levoglucosan was identified in Arctic glacier ice samples. This study suggests that the bulk of the DOM from these glaciers is a mixture of biologically labile molecules derived from microbes.

  16. Correlation of tryptophan fluorescence intensity decay parameters with sup 1 H NMR-determined rotamer conformations: (tryptophan sup 2 )oxytocin

    SciTech Connect

    Ross, J.B.A.; Schwartz, G.P.; Laws, W.R. ); Wyssbrod, H.R.; Porter, R.A. ); Michaels, C.A. )

    1992-02-18

    While the fluorescence decay kinetics of tyrosine model compounds can be explained in terms of heterogeneity derived from the three ground-state {chi}{sup 1} rotamers, a similar correlation has yet to be directly observed for a tryptophan residue. In addition, the asymmetric indole ring might also lead to heterogeneity from {chi}{sup 2} rotations. In this paper, the time-resolved and steady-state fluorescence properties of (tryptophan{sup 2})oxytocin at pH 3 are presented and compared with {sup 1}H NMR results. According to the unrestricted analyses of individual fluorescence decay curves taken as a function of emission wavelength-independent decay constants, only three exponential terms are required. In addition, the preexponential weighting factors (amplitudes) have the same relative relationship (weights) as the {sup 1}H NMR-determined {chi}{sup 1} rotamer populations of the indole side chain. {sup 15}N was used in heteronuclear coupling experiments to confirm the rotamer assignments. Inclusion of a linked function restricting the decay amplitudes to the {chi}{sup 1} rotamer populations in the individual decay curve analyses and in the global analysis confirms this correlation. According to qualitative nuclear Overhauser data, there are two {chi}{sup 2} populations.

  17. Analysis of the electronic, IR, and 1H NMR spectra of conjugated oligomers based on 4,4'-triphenylamine vinylene

    NASA Astrophysics Data System (ADS)

    Baryshnikov, G. V.; Minaeva, V. A.; Minaev, B. F.; Sun, V.-H.; Grigoras, M.

    2016-09-01

    Two types of conjugated oligomers based on 4,4'-triphenylamine vinylene have been synthesized and characterized by the methods of IR, UV-visible, and 1H NMR spectroscopy. The corresponding spectra have also been simulated theoretically at the density functional theory level with application of the B3LYP and BMK hybrid exchange-correlation functionals. A comparative analysis of the experimental and theoretical spectra of polymers and oligomers has revealed regularities of the manifestation of spectral signals depending on the conjugation chain length and the presence of a substituent in the triphenylamine core. It has been established, in particular, that the absolute intensity of IR bands satisfies a linear dependence with increase in the degree of polymerization; however, no frequency shift is observed at the same time. The position of the main peak in electron absorption spectra demonstrates the bathochromic shift with an increase in the oligomeric chain length due to the narrowing of the energy gap between the boundary molecular orbitals. Based on the theoretical estimation of the hydrogen atoms chemical shifts, the signals of various protons types in the strongly broadened experimental 1H NMR spectra of the bis-(4-iodine phenyl)-phenylamine and N,N-bis-(4-iodine phenyl)-4'-(phenylethynyl)-phenylamine polymerization products have also been identified.

  18. Adsorption mechanism at the molecular level between polymers and uremic octapeptide by the 2D 1H NMR Technique.

    PubMed

    Li, Guohua; Li, Jihong; Wang, Wei; Yang, Mei; Zhang, Yuanwei; Sun, Pingchuan; Yuan, Zhi; He, Binglin; Yu, Yaoting

    2006-06-01

    To remove uremic octapeptide from the blood stream of uremic patients, various modified polyacylamide cross-linked absorbents were prepared. Adsorption experiments showed these absorbents have significant differences in adsorption capacity to the target peptide. In this paper, two-dimension proton nuclear magnetic resonance (2D 1H NMR) spectroscopy was used to investigate the interaction mechanism between the peptide and the adsorbents. Because of the insolubility of the absorbent, some soluble linear polymers with the same functional groups as the absorbents were employed as the model adsorbents in 2D 1H NMR. The preferred binding site for the peptide and polymers was identified to be at the C-terminal carboxyl group of the octapeptide via chemical shift perturbation effects. In this study, we found that hydrogen bonding, electrostatic, and hydrophobic interactions all play a role in the interaction force but had different contributions. Especially, the great chemical shift changes of the aromatic amino acid residues (Trp) during the interaction between butyl-modified polyacrylamide and octapeptide suggested the hydrophobic interaction, incorporated with the electrostatic force, played an important role in the binding reaction in aqueous solutions. This information not only rationally explained the results of the adsorption experiments, but also identified the effective binding site and mechanism, and shall provide a structural basis for designing better affinity-type adsorbents for the target peptide.

  19. Development and Validation of Quantitative (1)H NMR Spectroscopy for the Determination of Total Phytosterols in the Marine Seaweed Sargassum.

    PubMed

    Zhang, Xiu-Li; Wang, Cong; Chen, Zhen; Zhang, Pei-Yu; Liu, Hong-Bing

    2016-08-10

    Knowledge of phytosterol (PS) contents in marine algae is currently lacking compared to those in terrestrial plants. The present studies developed a quantitative (1)H NMR method for the determination of the total PSs in Sargassum. The characteristic proton signal H-3α in PSs was used for quantification, and 2,3,4,5-tetrachloro-nitrobenzene was used as an internal standard. Seaweed samples could be recorded directly after total lipid extraction and saponification. The results showed that the PS contents in Sargassum fusiforme (788.89-2878.67 mg/kg) were significantly higher than those in Sargassum pallidum (585.33-1596.00 mg/kg). The variable contents in both species suggested that fixed raw materials are very important for future research and development. Orthogonal projection to latent structures discriminant analysis was carried out in the spectral region of δ 3.00-6.50 in the (1)H NMR spectrum. S. fusiforme and S. pallidum could be separated well, and the key sterol marker was fucosterol.

  20. Metabolomics in Lung Inflammation: A High Resolution 1H NMR Study of Mice Exposed to Silica Dust

    PubMed Central

    Hu, Jian Zhi; Rommereim, Donald N.; Minard, Kevin R.; Woodstock, Angie; Harrer, Bruce J.; Wind, Robert A.; Phipps, Richard P.; Sime, Patricia J.

    2010-01-01

    Here we report the first 1H NMR metabolomics studies on excised lungs and bronchoalveolar lavage fluid (BALF) from mice exposed to crystalline silica. High resolution 1H NMR metabolic profiling on intact excised lungs was performed using slow magic angle sample spinning (slow-MAS) 1H PASS (phase altered spinning sidebands) at a sample spinning rate of 80 Hz. Metabolic profiling on BALF was completed using fast magic angle spinning at 2kHz. Major findings are that the relative concentrations of choline, phosphocholine (PC) and glycerophosphocholine(GPC) were statistically significantly increased in silica-exposed mice compared to sham controls, indicating an altered membrane choline phospholipids metabolism (MCPM). The relative concentrations of glycogen/glucose, lactate and creatine were also statistically significantly increased in mice exposed to silica dust, suggesting that cellular energy pathways were affected by silica dust. Elevated levels of glycine, lysine, glutamate, proline and 4-hydroxyproline were also increased in exposed mice, suggesting the activation of a collagen pathway. Furthermore, metabolic profiles in mice exposed to silica dust were found to be spatially heterogeneous, in consistent with regional inflammation revealed by in vivo magnetic resonance imaging (MRI). PMID:20020862

  1. 1H NMR study of the phase transitions of trissarcosine calcium chloride single crystals at low temperature

    NASA Astrophysics Data System (ADS)

    Lee, Kyuhong; Lee, Moohee; Lee, Kwang Sei; Lim, Ae Ran

    2005-10-01

    The 1H NMR line-width and spin lattice relaxation time T1 of TSCC single crystals were studied. Variations in the temperature dependence of the spin lattice relaxation time were observed near 65 and 130 K, indicating drastic alterations of the spin dynamics at the phase transition temperatures. The changes in the temperature dependence of T1 near 65 and 130 K correspond to phase transitions of the crystal. The anomalous decrease in T1 around 130 K is due to the critical slowing down of the soft mode. The abrupt change in relaxation time at 65 K is associated with a structural phase transition. The proton spin lattice relaxation time of this crystal also has a minimum value in the vicinity of 185 K, which is governed by the reorientation of the CH3 groups of the sarcosine molecules. From this result, we conclude that the two phase transitions at 65 and 130 K can be discerned from abrupt variations in the 1H NMR relaxation behavior, and that 1H nuclei play important roles in the phase transitions of the TSCC single crystal.

  2. Effect of 1,10-phenanthroline aromaticity in carboxylic acids:1H NMR spectroscopy, GIAO calculations and thermodynamic properties

    NASA Astrophysics Data System (ADS)

    Machado, Camila M. B.; Santos, Vanessa F. C.; Belarmino, Marcia K. D. L.; França, José A. A.; Moura, Gustavo L. C.; Lima, Nathalia B. D.

    2016-08-01

    Hydrogen bonding represents a class of chemical interactions, which are directly responsible for several physical properties, such as: energetic stabilities, boiling points, vibrational modes, bond lengths, etc. In this article, we examine from the point of view of 1H NMR spectroscopy and GIAO calculations, the effects associated with the process of formation of the hydrogen bonds as they appear in the chemical shifts of the acidic hydrogens in the complexes between nitrogenated compounds, PHEN, BIPY and DIBIPY, and carboxylic acids, HOOCH, HOOCCH3 and HOOCC6H5. All computational simulations were performed using the quantum chemical methods B3LYP/6-31++G(d,p) and ωB97X-D/def2-TZVP. The 1H NMR spectroscopy results showed that, in both cases, the hydrogen nucleus of the OH group is the most affected in the process of hydrogen bond formation. For the complexes involving PHEN we observed that the hydrogen nucleus is more strongly shielded when compared with this signal in the corresponding complexes involving BIPY and DIBIPY.

  3. Metabolic Characterization of Advanced Liver Fibrosis in HCV Patients as Studied by Serum 1H-NMR Spectroscopy.

    PubMed

    Embade, Nieves; Mariño, Zoe; Diercks, Tammo; Cano, Ainara; Lens, Sabela; Cabrera, Diana; Navasa, Miquel; Falcón-Pérez, Juan M; Caballería, Joan; Castro, Azucena; Bosch, Jaume; Mato, José M; Millet, Oscar

    2016-01-01

    Several etiologies result in chronic liver diseases including chronic hepatitis C virus infection (HCV). Despite its high incidence and the severe economic and medical consequences, liver disease is still commonly overlooked due to the lack of efficient non-invasive diagnostic methods. While several techniques have been tested for the detection of fibrosis, the available biomarkers still present severe limitations that preclude their use in clinical diagnostics. Liver diseases have also been the subject of metabolomic analysis. Here, we demonstrate the suitability of 1H NMR spectroscopy for characterizing the metabolism of liver fibrosis induced by HCV. Serum samples from HCV patients without fibrosis or with liver cirrhosis were analyzed by NMR spectroscopy and the results were submitted to multivariate and univariate statistical analysis. PLS-DA test was able to discriminate between advanced fibrotic and non-fibrotic patients and several metabolites were found to be up or downregulated in patients with cirrhosis. The suitability of the most significantly regulated metabolites was validated by ROC analysis. Our study reveals that choline, acetoacetate and low-density lipoproteins are the most informative biomarkers for predicting cirrhosis in HCV patients. Our results demonstrate that statistical analysis of 1H-NMR spectra is able to distinguish between fibrotic and non-fibrotic patients suffering from HCV, representing a novel diagnostic application for NMR spectroscopy.

  4. The effect of standardized food intake on the association between BMI and 1H-NMR metabolites

    PubMed Central

    Schutte, Bianca A. M.; van den Akker, Erik B.; Deelen, Joris; van de Rest, Ondine; van Heemst, Diana; Feskens, Edith J. M.; Beekman, Marian; Slagboom, P. Eline

    2016-01-01

    Multiple studies have shown that levels of 1H-NMR metabolites are associated with disease and risk factors of disease such as BMI. While most previous investigations have been performed in fasting samples, meta-analysis often includes both cohorts with fasting and non-fasting blood samples. In the present study comprising 153 participants (mean age 63 years; mean BMI 27 kg/m2) we analyzed the effect of a standardized liquid meal (SLM) on metabolite levels and how the SLM influenced the association between metabolites and BMI. We observed that many metabolites, including glycolysis related metabolites, multiple amino acids, LDL diameter, VLDL and HDL lipid concentration changed within 35 minutes after a standardized liquid meal (SLM), similarly for all individuals. Remarkable, however, is that the correlations of metabolite levels with BMI remained highly similar before and after the SLM. Hence, as exemplified with the disease risk factor BMI, our results suggest that the applicability of 1H-NMR metabolites as disease biomarkers depends on the standardization of the fasting status rather than on the fasting status itself. Future studies are required to investigate the dependency of metabolite biomarkers for other disease risk factors on the fasting status. PMID:27966583

  5. Site-specific protonation kinetics of acidic side chains in proteins determined by pH-dependent carboxyl (13)C NMR relaxation.

    PubMed

    Wallerstein, Johan; Weininger, Ulrich; Khan, M Ashhar I; Linse, Sara; Akke, Mikael

    2015-03-04

    Proton-transfer dynamics plays a critical role in many biochemical processes, such as proton pumping across membranes and enzyme catalysis. The large majority of enzymes utilize acid-base catalysis and proton-transfer mechanisms, where the rates of proton transfer can be rate limiting for the overall reaction. However, measurement of proton-exchange kinetics for individual side-chain carboxyl groups in proteins has been achieved in only a handful of cases, which typically have involved comparative analysis of mutant proteins in the context of reaction network modeling. Here we describe an approach to determine site-specific protonation and deprotonation rate constants (kon and koff, respectively) of carboxyl side chains, based on (13)C NMR relaxation measurements as a function of pH. We validated the method using an extensively studied model system, the B1 domain of protein G, for which we measured rate constants koff in the range (0.1-3) × 10(6) s(-1) and kon in the range (0.6-300) × 10(9) M(-1) s(-1), which correspond to acid-base equilibrium dissociation constants (Ka) in excellent agreement with previous results determined by chemical shift titrations. Our results further reveal a linear free-energy relationship between log kon and pKa, which provides information on the free-energy landscape of the protonation reaction, showing that the variability among residues in these parameters arises primarily from the extent of charge stabilization of the deprotonated state by the protein environment. We find that side-chain carboxyls with extreme values of koff or kon are involved in hydrogen bonding, thus providing a mechanistic explanation for the observed stabilization of the protonated or deprotonated state.

  6. Solid state 13C NMR analysis of shales and coals from Laramide Basins. Final report, March 1, 1995--March 31, 1996

    SciTech Connect

    Miknis, F.P.; Jiao, Z.S.; Zhao, Hanqing; Surdam, R.C.

    1998-12-31

    This Western Research Institute (WRI) jointly sponsored research (JSR) project augmented and complemented research conducted by the University of Wyoming Institute For Energy Research for the Gas Research Institute. The project, {open_quotes}A New Innovative Exploitation Strategy for Gas Accumulations Within Pressure Compartments,{close_quotes} was a continuation of a project funded by the GRI Pressure Compartmentalization Program that began in 1990. That project, {open_quotes}Analysis of Pressure Chambers and Seals in the Powder River Basin, Wyoming and Montana,{close_quotes} characterized a new class of hydrocarbon traps, the discovery of which can provide an impetus to revitalize the domestic petroleum industry. In support of the UW Institute For Energy Research`s program on pressure compartmentalization, solid-state {sup 13}C NMR measurements were made on sets of shales and coals from different Laramide basins in North America. NMR measurements were made on samples taken from different formations and depths of burial in the Alberta, Bighorn, Denver, San Juan, Washakie, and Wind River basins. The carbon aromaticity determined by NMR was shown to increase with depth of burial and increased maturation. In general, the NMR data were in agreement with other maturational indicators, such as vitrinite reflectance, illite/smectite ratio, and production indices. NMR measurements were also obtained on residues from hydrous pyrolysis experiments on Almond and Lance Formation coals from the Washakie Basin. These data were used in conjunction with mass and elemental balance data to obtain information about the extent of carbon aromatization that occurs during artificial maturation. The data indicated that 41 and 50% of the original aliphatic carbon in the Almond and Lance coals, respectively, aromatized during hydrous pyrolysis.

  7. A {sup 13}C NMR study of the condensation chemistry of acetone and acetaldehyde adsorbed at the Bronsted acid sites in H-ZSM-5

    SciTech Connect

    Biaglow, A.I.; Sepa, J.; Gorte, R.J.

    1995-02-01

    Several bimolecular, acid-catalyzed condensation reactions of acetone and acetaldehyde have been examined in H-ZSM-5, along with the adsorption complexes formed by the products, using {sup 13}C NMR. For acetone, the hydrogen-bonded adsorption complex is stable at room temperature and coverages below one molecule per Broensted acid site. Reaction to mesityl oxide occurs only at higher coverages or temperatures, which are necessary to induce site exchange. The adsorption complex exhibits reaction chemistry analogous to that observed in solution phase, forming adsorption complexes of chloroacetone upon exposure to Cl{sub 2} and of imines upon exposure to NH{sub 3} or dimethylamine. The reactions of acetaldehyde to crotonaldehyde and imines are similar, although they occur at a faster rate due to the higher mobility of this molecule. The adsorption complexes formed by acetone, acetaldehyde, and their condensation products can all be described as rigid, hydrogen-bonded complexes at low coverages. Complexes formed from imines and enamines exhibit isotropic chemical shifts nearly identical to those observed in magic acids, indicating that proton transfer is nearly complete for these molecules. The extent of proton transfer for the remaining molecules varies with the proton affinity of the molecule, ranging from close to complete proton transfer for mesityl oxide and crotonaldehyde to almost complete absence of proton transfer for the chloroacetones. The differences and similarities between these reactions in the zeolite and in solution phase are discussed, along with the implications for understanding the primary processes responsible for these reactions in zeolites. 34 refs., 16 figs., 1 tab.

  8. Characteristics and degradation of carbon and phosphorus from aquatic macrophytes in lakes: Insights from solid-state (13)C NMR and solution (31)P NMR spectroscopy.

    PubMed

    Liu, Shasha; Zhu, Yuanrong; Meng, Wei; He, Zhongqi; Feng, Weiying; Zhang, Chen; Giesy, John P

    2016-02-01

    Water extractable organic matter (WEOM) derived from macrophytes plays an important role in biogeochemical cycling of nutrients, including carbon (C), nitrogen (N) and phosphorus (P) in lakes. However, reports of their composition and degradation in natural waters are scarce. Therefore, compositions and degradation of WEOM derived from six aquatic macrophytes species of Tai Lake, China, were investigated by use of solid-state (13)C NMR and solution (31)P NMR spectroscopy. Carbohydrates were the predominant constituents of WEOM fractions, followed by carboxylic acid. Orthophosphate (ortho-P) was the dominant form of P (78.7% of total dissolved P) in the water extracts, followed by monoester P (mono-P) (20.6%) and little diester P (0.65%). The proportion of mono-P in total P species increased with the percentage of O-alkyl and O-C-O increasing in the WEOM, which is likely due to degradation and dissolution of biological membranes and RNA from aquatic plants. Whereas the proportion of mono-P decreased with alkyl-C, NCH/OCH3 and COO/N-C=O increasing, which may be owing to the insoluble compounds including C functional groups of alkyl-C, NCH/OCH3 and COO/N-C=O, such as aliphatic biopolymers, lignin and peptides. Based on the results of this study and information in the literature about water column and sediment, we propose that WEOM, dominated by polysaccharides, are the most labile and bioavailable component in debris of macrophytes. Additionally, these WEOMs would also be a potential source for bioavailable organic P (e.g., RNA, DNA and phytate) for lakes.

  9. Characterization of the spherical intermediates and fibril formation of hCT in HEPES solution using solid-state 13C-NMR and transmission electron microscopy.

    PubMed

    Itoh-Watanabe, Hikari; Kamihira-Ishijima, Miya; Kawamura, Izuru; Kondoh, Masashi; Nakakoshi, Masamichi; Sato, Michio; Naito, Akira

    2013-10-21

    Human calcitonin (hCT) is a 32-amino acid peptide hormone that contains an intrachain disulfide bridge between Cys1 and Cys7 and a proline amide at the C-terminus. hCT tends to associate to form a fibril precipitate of the same type as amyloid fibrils, and hence has been studied as a model of amyloid fibril formation. The fibrillation process in N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid (HEPES) solution was examined using transmission electron microscopy. The rate of hCT fibrillation in HEPES solution was much lower than in phosphate buffer and acetic acid solution. Spherical intermediate aggregates (nuclei) were observed during the early stage of fibril formation. Short proto-fibrils appeared on the surface of the spherical intermediates. Subsequently, the spherical intermediates transformed directly into long proto-fibrils, which then elongated into mature hCT fibrils. The fibrillation process was also examined using solid-state (13)C-NMR spectroscopy, which indicated that the fibril structure was a β-sheet in the central region and a mixture of random coils and β-sheets at the C-terminus. The kinetics of fibril formation was examined in terms of a two-step autocatalytic reaction mechanism. The first-step nucleation rate (k1) was lower in HEPES solution than in phosphate buffer and acetic acid solution because the half-life of the intermediates is significantly longer in HEPES solution. In contrast, the second-step fibril elongation rate (k2) was similar in HEPES solution and acidic solutions. Specific interaction of HEPES molecules with hCT may stabilize the spherical intermediates and consequently inhibit the fibril elongation process of hCT.

  10. Solvent effect on pathways and mechanisms for D-fructose conversion to 5-hydroxymethyl-2-furaldehyde: in situ 13C NMR study.

    PubMed

    Kimura, Hiroshi; Nakahara, Masaru; Matubayasi, Nobuyuki

    2013-03-14

    Noncatalytic reactions of D-fructose were kinetically investigated in dimethylsulfoxide (DMSO), water, and methanol as a function of time at temperatures of 30-150 °C by applying in situ (13)C NMR spectroscopy. The products were quantitatively analyzed with distinction of isomeric species by taking advantage of site-selective (13)C labeling technique. In DMSO, D-fructose was converted first into 3,4-dihydroxy-2-dihydroxymethyl-5-hydroxymethyltetrahydrofuran having no double bond in the ring, subsequently into 4-hydroxy-5-hydroxymethyl-4,5-dihydrofuran-2-carbaldehyde having one double bond through dehydration, and finally into 5-hydroxymethyl-2-furaldehyde (5-HMF) having two double bonds. No other reaction pathways were involved, as shown from the carbon mass balance. In water, 5-HMF, the final product in DMSO, was generated with the precursors undetected and furthermore transformed predominantly into formic and levulinic acids and slightly into 1,2,4-benzenetriol accompanied by polymerization. D-glucose was also produced through the reversible transformation of the reactant D-fructose. In methanol, some kinds of anhydro-D-fructoses were generated instead of 5-HMF. The reaction pathways can thus be controlled by taking advantage of the solvent effect. The D-fructose conversion reactions are of the first order with respect to the concentration of D-fructose and proceed on the order of minutes in DMSO but on the order of hours in water and methanol. The rate constant was three orders of magnitude larger in DMSO than in water or methanol.

  11. 2H and 13C NMR studies on the temperature-dependent water and protein dynamics in hydrated elastin, myoglobin and collagen.

    PubMed

    Lusceac, Sorin A; Vogel, Michael R; Herbers, Claudia R

    2010-01-01

    (2)H NMR spin-lattice relaxation and line-shape analyses are performed to study the temperature-dependent dynamics of water in the hydration shells of myoglobin, elastin, and collagen. The results show that the dynamical behaviors of the hydration waters are similar for these proteins when using comparable hydration levels of h=0.25-0.43. Since water dynamics is characterized by strongly nonexponential correlation functions, we use a Cole-Cole spectral density for spin-lattice relaxation analysis, leading to correlation times, which are in nice agreement with results for the main dielectric relaxation process observed for various proteins in the literature. The temperature dependence can roughly be described by an Arrhenius law, with the possibility of a weak crossover in the vicinity of 220 K. Near ambient temperatures, the results substantially depend on the exact shape of the spectral density so that deviations from an Arrhenius behavior cannot be excluded in the high-temperature regime. However, for the studied proteins, the data give no evidence for the existence of a sharp fragile-to-strong transition reported for lysozyme at about 220 K. Line-shape analysis reveals that the mechanism for the rotational motion of hydration waters changes in the vicinity of 220 K. For myoglobin, we observe an isotropic motion at high temperatures and an anisotropic large-amplitude motion at low temperatures. Both mechanisms coexist in the vicinity of 220 K. (13)C CP MAS spectra show that hydration results in enhanced elastin dynamics at ambient temperatures, where the enhancement varies among different amino acids. Upon cooling, the enhanced mobility decreases. Comparison of (2)H and (13)C NMR data reveals that the observed protein dynamics is slower than the water dynamics.

  12. Chemical and nanometer-scale structure of kerogen and its change during thermal maturation investigated by advanced solid-state 13C NMR spectroscopy

    USGS Publications Warehouse

    Mao, J.; Fang, X.; Lan, Y.; Schimmelmann, A.; Mastalerz, Maria; Xu, L.; Schmidt-Rohr, K.

    2010-01-01

    We have used advanced and quantitative solid-state nuclear magnetic resonance (NMR) techniques to investigate structural changes in a series of type II kerogen samples from the New Albany Shale across a range of maturity (vitrinite reflectance R0 from 0.29% to 1.27%). Specific functional groups such as CH3, CH2, alkyl CH, aromatic CH, aromatic C-O, and other nonprotonated aromatics, as well as "oil prone" and "gas prone" carbons, have been quantified by 13C NMR; atomic H/C and O/C ratios calculated from the NMR data agree with elemental analysis. Relationships between NMR structural parameters and vitrinite reflectance, a proxy for thermal maturity, were evaluated. The aromatic cluster size is probed in terms of the fraction of aromatic carbons that are protonated (???30%) and the average distance of aromatic C from the nearest protons in long-range H-C dephasing, both of which do not increase much with maturation, in spite of a great increase in aromaticity. The aromatic clusters in the most mature sample consist of ???30 carbons, and of ???20 carbons in the least mature samples. Proof of many links between alkyl chains and aromatic rings is provided by short-range and long-range 1H-13C correlation NMR. The alkyl segments provide most H in the samples; even at a carbon aromaticity of 83%, the fraction of aromatic H is only 38%. While aromaticity increases with thermal maturity, most other NMR structural parameters, including the aromatic C-O fractions, decrease. Aromaticity is confirmed as an excellent NMR structural parameter for assessing thermal maturity. In this series of samples, thermal maturation mostly increases aromaticity by reducing the length of the alkyl chains attached to the aromatic cores, not by pronounced growth of the size of the fused aromatic ring clusters. ?? 2010 Elsevier Ltd. All rights reserved.

  13. Acetate stimulates flux through the tricarboxylic acid cycle in rabbit renal proximal tubules synthesizing glutamine from alanine: a 13C NMR study.

    PubMed Central

    Dugelay, S; Chauvin, M F; Megnin-Chanet, F; Martin, G; Laréal, M C; Lhoste, J M; Baverel, G

    1999-01-01

    Although glutamine synthesis has a major role in the control of acid-base balance and ammonia detoxification in the kidney of herbivorous species, very little is known about the regulation of this process. We therefore studied the influence of acetate, which is readily metabolized by the kidney and whose metabolism is accompanied by the production of bicarbonate, on glutamine synthesis from variously labelled [(13)C]alanine and [(14)C]alanine molecules in isolated rabbit renal proximal tubules. With alanine as sole exogenous substrate, glutamine and, to a smaller extent, glutamate and CO(2), were the only significant products of the metabolism of this amino acid, which was removed at high rates. Absolute fluxes through the enzymes involved in alanine conversion into glutamine were assessed by using a novel model describing the corresponding reactions in conjunction with the (13)C NMR, and to a smaller extent, the radioactive and enzymic data. The presence of acetate (5 mM) led to a large stimulation of fluxes through citrate synthase and alpha-oxoglutarate dehydrogenase. These effects were accompanied by increases in the removal of alanine, in the accumulation of glutamate and in flux through the anaplerotic enzyme pyruvate carboxylase. Acetate did not alter fluxes through glutamate dehydrogenase and glutamine synthetase; as a result, acetate did not change the accumulation of ammonia, which was negligible under both experimental conditions. We conclude that acetate, which seems to be an important energy-provider to the rabbit renal proximal tubule, simultaneously traps as glutamate the extra nitrogen removed as alanine, thus preventing the release of additional ammonia by the glutamate dehydrogenase reaction. PMID:10477267

  14. Detection of cerebral NAD(+) by in vivo (1)H NMR spectroscopy.

    PubMed

    de Graaf, Robin A; Behar, Kevin L

    2014-07-01

    Nicotinamide adenine dinucleotide (NAD(+)) plays a central role in cellular metabolism both as a coenzyme for electron-transfer enzymes as well as a substrate for a wide range of metabolic pathways. In the current study NAD(+) was detected on rat brain in vivo at 11.7T by 3D localized (1)H MRS of the NAD(+) nicotinamide protons in the 8.7-9.5 ppm spectral region. Avoiding water perturbation was critical to the detection of NAD(+) as strong, possibly indirect cross-relaxation between NAD(+) and water would lead to a several-fold reduction of the NAD(+) intensity in the presence of water suppression. Water perturbation was minimized through the use of localization by adiabatic spin-echo refocusing (LASER) in combination with frequency-selective excitation. The NAD(+) concentration in the rat cerebral cortex was determined at 296 ± 28 μm, which is in good agreement with recently published (31) P NMR-based results as well as results from brain extracts in vitro (355 ± 34 μm). The T1 relaxation time constants of the NAD(+) nicotinamide protons as measured by inversion recovery were 280 ± 65 and 1136 ± 122 ms in the absence and presence of water inversion, respectively. This confirms the strong interaction between NAD(+) nicotinamide and water protons as observed during water suppression. The T2 relaxation time constants of the NAD(+) nicotinamide protons were determined at 60 ± 13 ms after confounding effects of scalar coupling evolution were taken into account. The simplicity of the MR sequence together with the robustness of NAD(+) signal detection and quantification makes the presented method a convenient choice for studies on NAD(+) metabolism and function. As the method does not critically rely on magnetic field homogeneity and spectral resolution it should find immediate applications in rodents and humans even at lower magnetic fields.

  15. Toward an in Vivo Neurochemical Profile: Quantification of 18 Metabolites in Short-Echo-Time 1H NMR Spectra of the Rat Brain

    NASA Astrophysics Data System (ADS)

    Pfeuffer, Josef; Tkáč , Ivan; Provencher, Stephen W.; Gruetter, Rolf

    1999-11-01

    Localized in vivo1H NMR spectroscopy was performed with 2-ms echo time in the rat brain at 9.4 T. Frequency domain analysis with LCModel showed that the in vivo spectra can be explained by 18 metabolite model solution spectra and a highly structured background, which was attributed to resonances with fivefold shorter in vivo T1 than metabolites. The high spectral resolution (full width at half maximum approximately 0.025 ppm) and sensitivity (signal-to-noise ratio approximately 45 from a 63-μL volume, 512 scans) was used for the simultaneous measurement of the concentrations of metabolites previously difficult to quantify in 1H spectra. The strongly represented signals of N-acetylaspartate, glutamate, taurine, myo-inositol, creatine, phosphocreatine, glutamine, and lactate were quantified with Cramér-Rao lower bounds below 4%. Choline groups, phosphorylethanolamine, glucose, glutathione, γ-aminobutyric acid, N-acetylaspartylglutamate, and alanine were below 13%, whereas aspartate and scyllo-inositol were below 22%. Intra-assay variation was assessed from a time series of 3-min spectra, and the coefficient of variation was similar to the calculated Cramér-Rao lower bounds. Interassay variation was determined from 31 pooled spectra, and the coefficient of variation for total creatine was 7%. Tissue concentrations were found to be in very good agreement with neurochemical data from the literature.

  16. Metabolic responses of willow (Salix purpurea L.) leaves to mycorrhization as revealed by mass spectrometry and 1H NMR spectroscopy metabolite profiling

    PubMed Central

    Aliferis, Konstantinos A.; Chamoun, Rony; Jabaji, Suha

    2015-01-01

    The root system of most terrestrial plants form symbiotic interfaces with arbuscular mycorrhizal fungi (AMF), which are important for nutrient cycling and ecosystem sustainability. The elucidation of the undergoing changes in plants' metabolism during symbiosis is essential for understanding nutrient acquisition and for alleviation of soil stresses caused by environmental cues. Within this context, we have undertaken the task of recording the fluctuation of willow (Salix purpurea L.) leaf metabolome in response to AMF inoculation. The development of an advanced metabolomics/bioinformatics protocol employing mass spectrometry (MS) and 1H NMR analyzers combined with the in-house-built metabolite library for willow (http://willowmetabolib.research.mcgill.ca/index.html) are key components of the research. Analyses revealed that AMF inoculation of willow causes up-regulation of various biosynthetic pathways, among others, those of flavonoid, isoflavonoid, phenylpropanoid, and the chlorophyll and porphyrin pathways, which have well-established roles in plant physiology and are related to resistance against environmental stresses. The recorded fluctuation in the willow leaf metabolism is very likely to provide AMF-inoculated willows with a significant advantage compared to non-inoculated ones when they are exposed to stresses such as, high levels of soil pollutants. The discovered biomarkers of willow response to AMF inoculation and corresponding pathways could be exploited in biomarker-assisted selection of willow cultivars with superior phytoremediation capacity or genetic engineering programs. PMID:26042135

  17. Metabolomic profiling of the phytomedicinal constituents of Carica papaya L. leaves and seeds by 1H NMR spectroscopy and multivariate statistical analysis.

    PubMed

    Gogna, Navdeep; Hamid, Neda; Dorai, Kavita

    2015-11-10

    Extracts from the Carica papaya L. plant are widely reported to contain metabolites with antibacterial, antioxidant and anticancer activity. This study aims to analyze the metabolic profiles of papaya leaves and seeds in order to gain insights into their phytomedicinal constituents. We performed metabolite fingerprinting using 1D and 2D 1H NMR experiments and used multivariate statistical analysis to identify those plant parts that contain the most concentrations of metabolites of phytomedicinal value. Secondary metabolites such as phenyl propanoids, including flavonoids, were found in greater concentrations in the leaves as compared to the seeds. UPLC-ESI-MS verified the presence of significant metabolites in the papaya extracts suggested by the NMR analysis. Interestingly, the concentration of eleven secondary metabolites namely caffeic, cinnamic, chlorogenic, quinic, coumaric, vanillic, and protocatechuic acids, naringenin, hesperidin, rutin, and kaempferol, were higher in young as compared to old papaya leaves. The results of the NMR analysis were corroborated by estimating the total phenolic and flavonoid content of the extracts. Estimation of antioxidant activity in leaves and seed extracts by DPPH and ABTS in-vitro assays and antioxidant capacity in C2C12 cell line also showed that papaya extracts exhibit high antioxidant activity.

  18. 1H NMR Metabolomics: A New Molecular Level Tool for Assessment of Organic Contaminant Bioavailability to Earthworms in Soil

    NASA Astrophysics Data System (ADS)

    McKelvie, J. R.; Wolfe, D. M.; Celejewski, M. A.; Simpson, A. J.; Simpson, M. J.

    2009-05-01

    At contaminated field sites, the complete removal of polycyclic aromatic hydrocarbons (PAHs) is rarely achieved since a portion of these compounds remain tightly bound to the soil matrix. The concentration of PAHs in soil typically decreases until a plateau is reached, at which point the remaining contaminant is considered non- bioavailable. Numerous soil extraction techniques, including cyclodextrin extraction, have been developed to estimate contaminant bioavailability. However, these are indirect methods that do not directly measure the response of organisms to chemical exposure in soil. Earthworm metabolomics offers a promising new way to directly evaluate the bioavailability and toxicity of contaminants in soil. Metabolomics involves the measurement of changes in small-molecule metabolites, including sugars and amino acids, in living organisms due to an external stress, such as contaminant exposure. The objective of this study was to compare cyclodextrin extraction of soil (a bioavailability proxy) and 1H NMR metabolomic analysis of aqueous earthworm tissue extracts as indicators of contaminant bioavailability. A 30 day laboratory experiment was conducted using phenanthrene-spiked sphagnum peat soil and the OECD recommended earthworm species for toxicity testing, Eisenia fetida. The initial phenanthrene concentration in the soil was 320 mg/kg. Rapid biodegradation of phenanthrene occurred and concentrations decreased to 16 mg/kg within 15 days. After 15 days, phenanthrene biodegradation slowed and cyclodextrin extraction of the soil suggested that phenanthrene was no longer bioavailable. Multivariate statistical analysis of the 1H NMR spectra for E. fetida tissue extracts indicated that the metabolic profile of phenanthrene exposed earthworms differed from control earthworms throughout the 30 day experiment. This suggests that the residual phenanthrene remaining in the soil after 15 days continued to elicit a metabolic response, even though it was not

  19. Miscibility of nifedipine and hydrophilic polymers as measured by (1)H-NMR spin-lattice relaxation.

    PubMed

    Aso, Yukio; Yoshioka, Sumie; Miyazaki, Tamaki; Kawanishi, Tohru; Tanaka, Kazuyuki; Kitamura, Satoshi; Takakura, Asako; Hayashi, Takashi; Muranushi, Noriyuki

    2007-08-01

    The miscibility of a drug with excipients in solid dispersions is considered to be one of the most important factors for preparation of stable amorphous solid dispersions. The purpose of the present study was to elucidate the feasibility of (1)H-NMR spin-lattice relaxation measurements to assess the miscibility of a drug with excipients. Solid dispersions of nifedipine with the hydrophilic polymers poly(vinylpyrrolidone) (PVP), hydroxypropylmethylcellulose (HPMC) and alpha,beta-poly(N-5-hydroxypentyl)-L-aspartamide (PHPA) with various weight ratios were prepared by spray drying, and the spin-lattice relaxation decay of the solid dispersions in a laboratory frame (T(1) decay) and in a rotating frame (T(1rho) decay) were measured. T(1rho) decay of nifedipine-PVP solid dispersions (3 : 7, 5 : 5 and 7 : 3) was describable with a mono-exponential equation, whereas T(1rho) decay of nifedipine-PHPA solid dispersions (3 : 7, 4 : 6 and 5 : 5) was describable with a bi-exponential equation. Because a mono-exponential T(1rho) decay indicates that the domain sizes of nifedipine and polymer in solid dispersion are less than several nm, it is speculated that nifedipine is miscible with PVP but not miscible with PHPA. All the nifedipine-PVP solid dispersions studied showed a single glass transition temperature (T(g)), whereas two glass transitions were observed for the nifedipine-PHPA solid dispersion (3 : 7), thus supporting the above speculation. For nifedipine-HPMC solid dispersions (3 : 7 and 5 : 5), the miscibility of nifedipine and HPMC could not be determined by DSC measurements due to the lack of obviously evident T(g). In contrast, (1)H-NMR spin-lattice relaxation measurements showed that nifedipine and HPMC are miscible, since T(1rho) decay of the solid dispersions (3 : 7, 5 : 5 and 7 : 3) was describable with a mono-exponential equation. These results indicate that (1)H-NMR spin-lattice relaxation measurements are useful for assessing the miscibility of a drug and an

  20. Evaluation of the effect of carvacrol on the Escherichia coli 555 metabolome by using 1H-NMR spectroscopy.

    PubMed

    Picone, Gianfranco; Laghi, Luca; Gardini, Fausto; Lanciotti, Rosalba; Siroli, Lorenzo; Capozzi, Francesco

    2013-12-15

    Cultures of Escherichia coli 555 were grown at four levels of carvacrol (0-2 mM) and the E. coli endo-metabolome was extracted and measured by (1)H NMR spectroscopy. The results show that glucose concentration is going up with concentration of carvacrol and so do formate until the highest concentration is reached, from which point it suddenly decreases. This is interpreted as if the bacteria are increasingly unable to further metabolize glucose and as if the bacteria increasingly shifts with higher levels of carvacrol toward sugar fermentation as carbon source, until the level of carvacrol reaches a level (2.00 mM), where the E. coli must give up. Additionally, the multivariate Principal Component Analysis suggests that the adaptation occurring at sub-lethal doses of carvacrol is different from that occurring at higher doses.

  1. Study of the Cardiotoxicity of Venenum Bufonis in Rats using an 1H NMR-Based Metabolomics Approach

    PubMed Central

    Wang, Junsong; Guo, Pingping; Li, Minghui; Yang, Minghua; Kong, Lingyi

    2015-01-01

    Venenum Bufonis, a well-known traditional Chinese medicine, has been widely used in Asia and has gained popularity in Western countries over the last decade. Venenum Bufonis has obvious side effects that have been observed in clinical settings, but few studies have reported on its cardiotoxicity. In this work, the cardiotoxicity of Venenum Bufonis was investigated using a 11H NMR-based metabolomics approach. The 1H NMR profiles of the serum, myocardial extracts and liver extracts of specific-pathogen-free rats showed that Venenum Bufonis produced significant metabolic perturbations dose-dependently with a distinct time effect, peaking at 2 hr after dosing and attenuating gradually. Clinical chemistry, electrocardiographic recordings, and histopathological evaluation provided additional evidence of Venenum Bufonis-induced cardiac damage that complemented and supported the metabolomics findings. The combined results demonstrated that oxidative stress, mitochondrial dysfunction, and energy metabolism perturbations were associated with the cardiac damage that results from Venenum Bufonis. PMID:25781638

  2. Study of the formation of carbonyl compounds in edible oils and fats by 1H-NMR and FTIR

    NASA Astrophysics Data System (ADS)

    Moya Moreno, M. C. M.; Mendoza Olivares, D.; Amézquita López, F. J.; Peris Martínez, V.; Bosch Reig, F.

    1999-05-01

    Oils and fats start decomposing from the moment they are isolated from their natural environment. Heating accelerates oxidative rancidity and frying at high temperatures produces thermal degradation with the formation of decomposition products, such as aldehydes, ketones, free acids and hydroxilic compounds that in high levels can be harmful to human health. The decomposition products formed up to 300°C were determined by means of 1H-NMR spectroscopy and an FTIR spectroscopic method was developed for the quantification of carbonyl compounds generated during heating. The results show that there is a formation of carbonyl compounds starting at 150°C and when the sample was heated at 300°C for 40 min, the following contents (expressed as butyraldehyde mass fraction) were found: olive oil 10.5%, sunflower oil 11.3%, corn oil 3.0%, seeds oil (sunflower, safflower and canola seed) 6.6% and lard 3.5%.

  3. IR, 1H NMR, mass, XRD and TGA/DTA investigations on the ciprofloxacin/iodine charge-transfer complex

    NASA Astrophysics Data System (ADS)

    Refat, Moamen S.; El-Hawary, W. F.; Moussa, Mohamed A. A.

    2011-05-01

    The charge-transfer complex (CTC) of ciprofloxacin drug (CIP) as a donor with iodine (I 2) as a sigma acceptor has been studied spectrophotometrically in CHCl 3. At maximum absorption bands, the stoichiometry of CIP:iodine system was found to be 1:1 ratio according to molar ratio method. The essential spectroscopic data like formation constant ( KCT), molar extinction coefficient ( ɛCT), standard free energy (Δ G°), oscillator strength ( f), transition dipole moment ( μ), resonance energy ( RN) and ionization potential ( ID) were estimated. The spectroscopic techniques such as IR, 1H NMR, mass and UV-vis spectra and elemental analyses (CHN) as well as TG-DTG and DTA investigations were used to characterize the chelating behavior of CIP/iodine charge-transfer complex. The iodine CT interaction was associated with a presence of intermolecular hydrogen bond. The X-ray investigation was carried out to investigate the iodine doping in the synthetic CT complex.

  4. (1)H NMR spectroscopy-guided isolation of new sucrose esters from Physalis alkekengi var. franchetii and their antibacterial activity.

    PubMed

    Zhang, Chuan-Yang; Luo, Jian-Guang; Liu, Rui-Huan; Lin, Ru; Yang, Ming-Hua; Kong, Ling-Yi

    2016-10-01

    Ten new sucrose esters, physakengoses A-J (1-10), were isolated from the aerial parts of Physalis alkekengi var. franchetii under the guidance of (1)H NMR spectroscopy. Their structures were determined by spectroscopic analyses (HRESIMS, 1D and 2D NMR, and ESIMS) and chemical methods. These new compounds were tested for antibacterial activities against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli. Among them, compounds 2 and 5-8 showed potent inhibitory effects against test strains with MIC values ranging from 3.5 to 14.9μg/mL. These findings may indicate that the P. alkekengi var. franchetii has potential application as an ingredient in pharmaceuticals.

  5. In vitro interaction of selected phospholipid species with mercuric chloride using Fourier transform sup 1 H-NMR

    SciTech Connect

    Shinada, Masayuki; Muto, Hajime; Takizawa, Yukio )

    1991-09-01

    Many studies on the mercury toxicities have been accumulated since the outbreak of Minamata Disease.' There have been few reports on the reaction mechanisms of mercurials with phospholipids which substantially locate in biological membranes, although the interactions of nucleotides or nucleosides with mercurials have been reported. Recently, the study on the interaction of mercuric chloride (HgCl{sub 2}) with amino polar heads of model membranes containing phosphatidylserine (PS) and phosphatidylethanolamine (PE) has been reported, as the results from the fluorescence polarization analysis using 1,6-diphenyl-1,3,5-hexatriene. The authors demonstrate here the interactions of dioleoylphosphatidylethanolamine (DOPE) and dioleoylphosphatidylcholine (DOPC) with HgCl{sub 2}, using Fourier transform {sup 1}H-NMR ({sup 1}H-FT-NMR).

  6. 1H NMR analysis of complexation of hydrotropic agents nicotinamide and caffeine with aromatic biologically active molecules in aqueous solution

    NASA Astrophysics Data System (ADS)

    Lantushenko, Anastasia O.; Mukhina, Yulia V.; Veselkov, Kyrill A.; Davies, David B.; Veselkov, Alexei N.

    2004-07-01

    NMR spectroscopy has been used to elucidate the molecular mechanism of solubilization action of hydrotropic agents nicotinamide (NA) and caffeine (CAF). Hetero-association of NA with riboflavine-mononucleotide (FMN) and CAF with low soluble in aqueous solution synthetic analogue of antibiotic actinomycin D, actinocyl-bis-(3-dimethylaminopropyl) amine (Actill), has been investigated by 500 MHz 1H NMR spectroscopy. Concentration and temperature dependences of proton chemical shifts have been analysed in terms of a statistical-thermodynamic model of indefinite self- and heteroassociation of aromatic molecules. The obtained results enable to conclude that NA-FMN and CAF-Actill intermolecular complexes are mainly stabilized by the stacking interactions of the aromatic chromophores. Hetero-association of the investigated molecules plays an important role in solubilization of aromatic drugs by hydrotropic agents nicotinamide and caffeine.

  7. [Studies by means of 1H NMR spectroscopy of complex formation of aromatic biologically active compounds with antibiotic topotecan].

    PubMed

    Mosunov, A A; Kostiukov, V V; Evstigneev, M P

    2012-01-01

    The analysis of heteroassociation of antibiotic topotecan (TPT) with aromatic biologically active compounds (BAC): caffeine, mutagens ethidium bromide and proflavine, antibiotic daunomycin, vitamins flavin-mononucleotide and nicotinamide, has been carried out in the work using 1H NMR spectroscopy data. The equilibrium constants of heteroassociation and induced chemical shifts of the protons have been obtained in the complexes with BAC. It is found that the complex formation TPT-BAC has the nature of stacking of the chromophores, additionally stabilized in the case of proflavine by intermolecular hydrogen bond. Calculation of the basic components of the Gibbs free energy of the complexation reactions is carried out, and the factors which stabilize and destabilize the heterocomplexes of molecules are revealed.

  8. Metabolite profiling of Clinacanthus nutans leaves extracts obtained from different drying methods by 1H NMR-based metabolomics

    NASA Astrophysics Data System (ADS)

    Hashim, Noor Haslinda Noor; Latip, Jalifah; Khatib, Alfi

    2016-11-01

    The metabolites of Clinacanthus nutans leaves extracts and their dependence on drying process were systematically characterized using 1H nuclear magnetic resonance spectroscopy (NMR) multivariate data analysis. Principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA) were able to distinguish the leaves extracts obtained from different drying methods. The identified metabolites were carbohydrates, amino acid, flavonoids and sulfur glucoside compounds. The major metabolites responsible for the separation in PLS-DA loading plots were lupeol, cycloclinacosides, betulin, cerebrosides and choline. The results showed that the combination of 1H NMR spectroscopy and multivariate data analyses could act as an efficient technique to understand the C. nutans composition and its variation.

  9. Bonding in hard and elastic amorphous carbon nitride films investigated using 15N, 13C, and 1H NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Gammon, W. J.; Hoatson, G. L.; Holloway, B. C.; Vold, R. L.; Reilly, A. C.

    2003-11-01

    The nitrogen bonding in hard and elastic amorphous carbon nitride (a-CNx) films is examined with 15N, 13C, and 1H nuclear magnetic resonance (NMR) spectroscopy. Films were deposited by dc magnetron sputtering, in a pure nitrogen discharge on Si(001) substrates at 300 °C. Nanoindentation tests revealed an elastic recovery of 80%, a hardness of 5 GPa, and an elastic modulus of 47 GPa. The NMR results show that nitrogen bonding in this material is consistent with sp2 hybridized nitrogen incorporated in an aromatic carbon environment. The data also indicate that the a-CNx prepared for this study has very low hydrogen content and is hydrophilic. Specifically, analysis of 15N and 13C cross polarization magic angle spinning and 1H NMR experiments suggests that water preferentially protonates nitrogen sites.

  10. Two-dimensional sup 1 H NMR studies on HPr protein from Staphylococcus aureus: Complete sequential assignments and secondary structure

    SciTech Connect

    Kalbitzer, H.R.; Neidig, K.P. ); Hengstenberg, W. )

    1991-11-19

    Complete sequence-specific assignments of the {sup 1}H NMR spectrum of HPr protein from Staphylococcus aureus were obtained by two-dimensional NMR methods. Important secondary structure elements that can be derived from the observed nuclear Overhauser effects are a large antiparallel {beta}-pleated sheet consisting of four strands, A, B, C, D, a segment S{sub AB} consisting of an extended region around the active-center histidine (His-15) and an {alpha}-helix, a half-turn between strands B and C, a segment S{sub CD} which shows no typical secondary structure, and the {alpha}-helical, C-terminal segment S{sub term}. These general structural features are similar to those found earlier in HPr proteins from different microorganisms such as Escherichia coli, Bacillus subtilis, and Streptococcus faecalis.

  11. Combining biochemical with (1)H NMR-based metabolomics approach unravels the antidiabetic activity of genipin and its possible mechanism.

    PubMed

    Shen, Xiao-Li; Liu, Huan; Xiang, Huan; Qin, Xue-Mei; Du, Guan-Hua; Tian, Jun-Sheng

    2016-09-10

    Diabetes mellitus is a typical heterogeneous metabolic disorder characterized by abnormal metabolism of carbohydrates, lipids and proteins. Genipin possesses a wide spectrum of biological activities including ameliorating effects on diabetes, but the definite mechanism of this effect remains unknown. To investigate the antidiabetic activities of genipin and explore the biochemical changes of serum endogenous metabolites on diabetic rats induced by alloxan, (1)H NMR spectroscopy coupled with multivariate data analysis was used to. All rats were randomly divided into six groups including negative control (NC) group, diabetic mellitus (DM) group, metformin hydrochloride group, high dose group of genipin, middle dose group of genipin and low dose group of genipin. Diabetes was induced by a single intraperitoneal injection of 120mg/kg body weight of alloxan. Serum samples were collected for the (1)H NMR-based metabolomics and clinical biochemical analysis. Daily oral administration of genipin (25, 50 and 100mg/kg body weight) and metformin hydrochloride (125mg/kg) for two weeks showed beneficial effects on blood glucose level (P<0.01). Significant differences in the metabolic profile as well as the result of biochemical parameters between the diabetic group and the control group were observed. The PLS-DA scores and corresponding loading plots demonstrated that genipin significantly restored the abnormal metabolic state. Detailed analysis of the altered metabolite levels indicated that genipin significantly ameliorated the disturbance in glucose metabolism, tricarboxylic acid cycle, lipid metabolism and amino acid metabolism. Genipin showed the best anti-diabetic effects at a dose of 100mg/kg in rats. This finding indicates that chemical and metabolomic approaches could be powerful tools for the investigation of the biochemical changes in pathological conditions or drug treatment.

  12. Metabolic Study of Breast MCF-7 Tumor Spheroids after Gamma Irradiation by 1H NMR Spectroscopy and Microimaging

    PubMed Central

    Palma, Alessandra; Grande, Sveva; Luciani, Anna Maria; Mlynárik, Vladimír; Guidoni, Laura; Viti, Vincenza; Rosi, Antonella

    2016-01-01

    Multicellular tumor spheroids are an important model system to investigate the response of tumor cells to radio- and chemotherapy. They share more properties with the original tumor than cells cultured as 2D monolayers do, which helps distinguish the intrinsic properties of monolayer cells from those induced during cell aggregation in 3D spheroids. The paper investigates some metabolic aspects of small tumor spheroids of breast cancer and their originating MCF-7 cells, grown as monolayer, by means of high–resolution (HR) 1H NMR spectroscopy and MR microimaging before and after gamma irradiation. The spectra of spheroids were characterized by higher intensity of mobile lipids, mostly neutral lipids, and glutamine (Gln) signals with respect to their monolayer cells counterpart, mainly owing to the lower oxygen supply in spheroids. Morphological changes of small spheroids after gamma-ray irradiation, such as loss of their regular shape, were observed by MR microimaging. Lipid signal intensity increased after irradiation, as evidenced in both MR localized spectra of the single spheroid and in HR NMR spectra of spheroid suspensions. Furthermore, the intense Gln signal from spectra of irradiated spheroids remained unchanged, while the low Gln signal observed in monolayer cells increased after irradiation. Similar results were observed in cells grown in hypoxic conditions. The different behavior of Gln in 2D monolayers and in 3D spheroids supports the hypothesis that a lower oxygen supply induces both an upregulation of Gln synthetase and a downregulation of glutaminases with the consequent increase in Gln content, as already observed under hypoxic conditions. The data herein indicate that 1H NMR spectroscopy can be a useful tool for monitoring cell response to different constraints. The use of spheroid suspensions seems to be a feasible alternative to localized spectroscopy since similar effects were found after radiation treatment. PMID:27200293

  13. 1H NMR Metabolic Fingerprinting to Probe Temporal Postharvest Changes on Qualitative Attributes and Phytochemical Profile of Sweet Cherry Fruit

    PubMed Central

    Goulas, Vlasios; Minas, Ioannis S.; Kourdoulas, Panayiotis M.; Lazaridou, Athina; Molassiotis, Athanassios N.; Gerothanassis, Ioannis P.; Manganaris, George A.

    2015-01-01

    Sweet cherry fruits (Prunus avium cvs. ‘Canada Giant’, ‘Ferrovia’) were harvested at commercial maturity stage and analyzed at harvest and after maintenance at room temperature (storage at ∼20°C, shelf life) for 1, 2, 4, 6, and 8 days, respectively. Fruit were initially analyzed for respiration rate, qualitative attributes and textural properties: ‘Canada Giant’ fruit were characterized by higher weight losses and stem browning index, being more intense over the late stages of shelf life period; meanwhile ‘Ferrovia’ possessed appreciably better performance even after extended shelf life period. A gradual decrease of respiration rate was monitored in both cultivars, culminated after 8 days at 20°C. The sweet cherry fruit nutraceutical profile was monitored using an array of instrumental techniques (spectrophotometric assays, HPLC, 1H-NMR). Fruit antioxidant capacity was enhanced with the progress of shelf life period, concomitant with the increased levels of total anthocyanin and of phenolic compounds. ‘Ferrovia’ fruit presented higher contents of neochlorogenic acid and p-coumaroylquinic acid throughout the shelf life period. We further developed an 1H-NMR method that allows the study of primary and secondary metabolites in a single running, without previous separation and isolation procedures. Diagnostic peaks were located in the aliphatic region for sugars and organic acids, in the aromatic region for phenolic compounds and at 8.2–8.6 ppm for anthocyanins. This NMR-based methodology provides a unifying tool for quantitative and qualitative characterization of metabolite changes of sweet cherry fruits; it is also expected to be further exploited for monitoring temporal changes in other fleshy fruits. PMID:26617616

  14. A 1H NMR study of a ternary peptide complex that mimics the interaction between troponin C and troponin I.

    PubMed Central

    Slupsky, C. M.; Shaw, G. S.; Campbell, A. P.; Sykes, B. D.

    1992-01-01

    The troponin I peptide N alpha-acetyl TnI (104-115) amide (TnIp) represents the minimum sequence necessary for inhibition of actomyosin ATPase activity of skeletal muscle (Talbot, J.A. & Hodges, R.S. 1981, J. Biol. Chem. 256, 2798-3802; Van Eyk, J.E. & Hodges, R.S., 1988, J. Biol. Chem. 263, 1726-1732; Van Eyk, J.E., Kay, C.M., & Hodges, R.S., 1991, Biochemistry 30, 9974-9981). In this study, we have used 1H NMR spectroscopy to compare the binding of this inhibitory TnI peptide to a synthetic peptide heterodimer representing site III and site IV of the C-terminal domain of troponin C (TnC) and to calcium-saturated skeletal TnC. The residues whose 1H NMR chemical shifts are perturbed upon TnIp binding are the same in both the site III/site IV heterodimer and TnC. These residues include F102, I104, F112, I113, I121, I149, D150, F151, and F154, which are all found in the C-terminal domain hydrophobic pocket and antiparallel beta-sheet region of the synthetic site III/site IV heterodimer and of TnC. Further, the affinity of TnIp binding to the heterodimer (Kd = 192 +/- 37 microM) was found to be similar to TnIp binding to TnC (48 +/- 18 microM [Campbell, A.P., Cachia, P.J., & Sykes, B.D., 1991, Biochem. Cell Biol. 69, 674-681]). The results indicate that binding of the inhibitory region of TnI is primarily to the C-terminal domain of TnC. The results also indicate how well the synthetic peptide heterodimer mimics the C-terminal domain of TnC in structure and functional interactions. PMID:1304891

  15. Prognosis Biomarkers of Severe Sepsis and Septic Shock by 1H NMR Urine Metabolomics in the Intensive Care Unit.

    PubMed

    Garcia-Simon, Monica; Morales, Jose M; Modesto-Alapont, Vicente; Gonzalez-Marrachelli, Vannina; Vento-Rehues, Rosa; Jorda-Miñana, Angela; Blanquer-Olivas, Jose; Monleon, Daniel

    2015-01-01

    Early diagnosis and patient stratification may improve sepsis outcome by a timely start of the proper specific treatment. We aimed to identify metabolomic biomarkers of sepsis in urine by (1)H-NMR spectroscopy to assess the severity and to predict outcomes. Urine samples were collected from 64 patients with severe sepsis or septic shock in the ICU for a (1)H NMR spectra acquisition. A supervised analysis was performed on the processed spectra, and a predictive model for prognosis (30-days mortality/survival) of sepsis was constructed using partial least-squares discriminant analysis (PLS-DA). In addition, we compared the prediction power of metabolomics data respect the Sequential Organ Failure Assessment (SOFA) score. Supervised multivariate analysis afforded a good predictive model to distinguish the patient groups and detect specific metabolic patterns. Negative prognosis patients presented higher values of ethanol, glucose and hippurate, and on the contrary, lower levels of methionine, glutamine, arginine and phenylalanine. These metabolites could be part of a composite biopattern of the human metabolic response to sepsis shock and its mortality in ICU patients. The internal cross-validation showed robustness of the metabolic predictive model obtained and a better predictive ability in comparison with SOFA values. Our results indicate that NMR metabolic profiling might be helpful for determining the metabolomic phenotype of worst-prognosis septic patients in an early stage. A predictive model for the evolution of septic patients using these metabolites was able to classify cases with more sensitivity and specificity than the well-established organ dysfunction score SOFA.

  16. Prognosis Biomarkers of Severe Sepsis and Septic Shock by 1H NMR Urine Metabolomics in the Intensive Care Unit

    PubMed Central

    Modesto-Alapont, Vicente; Gonzalez-Marrachelli, Vannina; Vento-Rehues, Rosa; Jorda-Miñana, Angela; Blanquer-Olivas, Jose; Monleon, Daniel

    2015-01-01

    Early diagnosis and patient stratification may improve sepsis outcome by a timely start of the proper specific treatment. We aimed to identify metabolomic biomarkers of sepsis in urine by 1H-NMR spectroscopy to assess the severity and to predict outcomes. Urine samples were collected from 64 patients with severe sepsis or septic shock in the ICU for a 1H NMR spectra acquisition. A supervised analysis was performed on the processed spectra, and a predictive model for prognosis (30-days mortality/survival) of sepsis was constructed using partial least-squares discriminant analysis (PLS-DA). In addition, we compared the prediction power of metabolomics data respect the Sequential Organ Failure Assessment (SOFA) score. Supervised multivariate analysis afforded a good predictive model to distinguish the patient groups and detect specific metabolic patterns. Negative prognosis patients presented higher values of ethanol, glucose and hippurate, and on the contrary, lower levels of methionine, glutamine, arginine and phenylalanine. These metabolites could be part of a composite biopattern of the human metabolic response to sepsis shock and its mortality in ICU patients. The internal cross-validation showed robustness of the metabolic predictive model obtained and a better predictive ability in comparison with SOFA values. Our results indicate that NMR metabolic profiling might be helpful for determining the metabolomic phenotype of worst-prognosis septic patients in an early stage. A predictive model for the evolution of septic patients using these metabolites was able to classify cases with more sensitivity and specificity than the well-established organ dysfunction score SOFA. PMID:26565633

  17. Quantitative Quantum Mechanical Spectral Analysis (qQMSA) of (1)H NMR spectra of complex mixtures and biofluids.

    PubMed

    Tiainen, Mika; Soininen, Pasi; Laatikainen, Reino

    2014-05-01

    The quantitative interpretation of (1)H NMR spectra of mixtures like the biofluids is a demanding task due to spectral complexity and overlap. Complications may arise also from water suppression, T2-editing, protein interactions, relaxation differences of the species, experimental artifacts and, furthermore, the spectra may contain unknown components and macromolecular background which cannot be easily separated from baseline. In this work, tools and strategies for quantitative Quantum Mechanical Spectral Analysis (qQMSA) of (1)H NMR spectra from complex mixtures were developed and systematically assessed. In the present approach, the signals of well-defined, stoichiometric components are described by a QM model, while the background is described by a multiterm baseline function and the unknown signals using optimizable and adjustable lines, regular multiplets or any spectral structures which can be composed from spectral lines. Any prior knowledge available from the spectrum can also be added to the model. Fitting strategies for weak and strongly overlapping spectral systems were developed and assessed using two basic model systems, the metabolite mixtures without and with macromolecular (serum) background. The analyses show that if the spectra are measured in high-throughput manner, the consistent absolute quantification demands some calibration to compensate the different response factors of the protons and compounds. On the other hand, the results show that also the T2-edited spectra can be measured so that they obey well the QM rules. In general, qQMSA exploits and interprets the spectral information in maximal way taking full advantage from the QM properties of the spectra and, at the same time, offers chemical confidence which means that individual components can be identified with high confidence on the basis of their accurate spectral parameters.

  18. Metabolic profiling studies on the toxicological effects of realgar in rats by {sup 1}H NMR spectroscopy

    SciTech Connect

    Wei Lai; Liao Peiqiu; Wu Huifeng; Li Xiaojing Pei Fengkui Li Weisheng; Wu Yijie

    2009-02-01

    The toxicological effects of realgar after intragastrical administration (1 g/kg body weight) were investigated over a 21 day period in male Wistar rats using metabonomic analysis of {sup 1}H NMR spectra of urine, serum and liver tissue aqueous extracts. Liver and kidney histopathology examination and serum clinical chemistry analyses were also performed. {sup 1}H NMR spectra and pattern recognition analyses from realgar treated animals showed increased excretion of urinary Kreb's cycle intermediates, increased levels of ketone bodies in urine and serum, and decreased levels of hepatic glucose and glycogen, as well as hypoglycemia and hyperlipoidemia, suggesting the perturbation of energy metabolism. Elevated levels of choline containing metabolites and betaine in serum and liver tissue aqueous extracts and increased serum creatine indicated altered transmethylation. Decreased urinary levels of trimethylamine-N-oxide, phenylacetylglycine and hippurate suggested the effects on the gut microflora environment by realgar. Signs of impairment of amino acid metabolism were supported by increased hepatic glutamate levels, increased methionine and decreased alanine levels in serum, and hypertaurinuria. The observed increase in glutathione in liver tissue aqueous extracts could be a biomarker of realgar induced oxidative injury. Serum clinical chemistry analyses showed increased levels of lactate dehydrogenase, aspartate aminotransferase, and alkaline phosphatase as well as increased levels of blood urea nitrogen and creatinine, indicating slight liver and kidney injury. The time-dependent biochemical variations induced by realgar were achieved using pattern recognition methods. This work illustrated the high reliability of NMR-based metabonomic approach on the study of the biochemical effects induced by traditional Chinese medicine.

  19. Detection, identification and quantification by 1H NMR of adulterants in 150 herbal dietary supplements marketed for improving sexual performance.

    PubMed

    Gilard, Véronique; Balayssac, Stéphane; Tinaugus, Aurélie; Martins, Nathalie; Martino, Robert; Malet-Martino, Myriam

    2015-01-01

    One hundred and fifty dietary supplements (DS) marketed to increase sexual performance were analyzed. All these formulations were claimed to contain only natural compounds, plant extracts and/or vitamins. (1)H NMR spectroscopy was used for detecting the presence of adulterants and for their identification and quantification. Mass spectrometry was used as a complementary method for confirming the chemical structures. 61% of DS were adulterated with phosphodiesterase-5 inhibitors (PDE-5i) (27% with the PDE-5i medicines sildenafil, tadalafil and vardenafil, and 34% with their structurally modified analogues). Among them, 64% contained only one PDE-5i and 36% mixtures of two, three and even four. The amounts of PDE-5i medicines were higher than the maximum recommended dose in 25% of DS tainted with these drugs. Additional 5.5% DS included other drugs for the treatment of sexual dysfunction (yohimbine, flibanserin, phentolamine, dehydroepiandrosterone or testosterone). Some DS (2.5%) contained products (osthole, icariin) extracted from plants known to improve sexual performance. Only 31% of the samples could be considered as true herbal/natural products. A follow-up over time of several DS revealed that manufacturers make changes in the chemical composition of the formulations. Lack of quality or consistent manufacture (contamination possibly due to inadequate cleaning of the manufacturing chain, presence of impurities or degradation products, various compositions of a given DS with the same batch number, inadequate labelling) indicated poor manufacturing practices. In conclusion, this paper demonstrates the power of (1)H NMR spectroscopy as a first-line method for the detection of adulterated herbal/natural DS and the need for more effective quality control of purported herbal DS.

  20. I. The synthesis and characterization of annulated uranocenes. II. The variable temperature /sup 1/H NMR of uranocenes

    SciTech Connect

    Luke, W.D.

    1980-01-01

    A general synthetic route to alkyl annulated cyclooctatetraene dianions and the corresponding annulated uranocenes has been developed. Dideprotonation of bicyclooctatrienes, resulting from reaction of cyclooctatetraene dianion with l,n-dialkylbromides or methanesulfonates, affords alkyl annulated cyclooctatetraene dianions in moderate yields. Dicyclopenteno-, bisdimethylcyclopenteno- and dicyclohexenouranocene were prepared from the corresponding cyclooctatetraene dianions and UCl/sub 4/. The structures of dicyclobuteno- and dicyclopentenouranocene were elucidated by single crystal X-ray diffraction, and the effects of annulation on the uranocene skeleton are discussed. Attempted synthesis of benzocyclooctatetraene and a benzannulated uranocene is reported. The variable temperature /sup 1/H NMR spectrum of uranocene has been reinvestigated from -100 to 100/sup 0/C. The isotropic shift was found to be linear in T/sup -1/ with an extrapolated intercept of 0 at T/sup -1/ = 0. Variable temperature /sup 1/H NMR spectra, from -80 to 70/sup 0/C, of 17 substituted uranocenes are reported. The energy barrier to ring rotation in 1,1', 4,4'-tetra-t-butyl-uranocene was determined to be 8.24 +- 0.5 kcal/mole while the barrier in the corresponding 1,1', 3,3'-tetra-t-butylferrocene was determined to be 13.1 kcal/mole. Alkyl substitution is shown to have little effect on the electronic and magnetic properties of the uranocene skeleton, and thus alkyl substituted uranocenes are treated as having effective axial symmetry in analysis of the observed isotropic shifts. Using diannulated uranocenes as model systems an analysis of the contact and pseudocontact components of the observed isotropic shifts in uranocene and alkyl substituted uranocenes is presented.

  1. Solid-state sup 13 C NMR of the retinal chromophore in photointermediates of bacteriorhodopsin: Characterization of two forms of M

    SciTech Connect

    Smith, S.O.; Courtin, J.; van den Berg, E.; Winkel, C.; Lugtenburg, J.; Herzfeld, J.; Griffin, R.G. )

    1989-01-10

    Solid-state {sup 13}C NMR spectra of the M photocycle intermediate of bacteriorhodopsin (bR) have been obtained from purple membrane regenerated with retinal specifically {sup 13}C labeled at positions 5, 12, 13, 14, and 15. The M intermediate was trapped at {minus}40{degree}C and pH = 9.5-10.0 in either 100 mM NaCl (M (NaCl)) or 500 mM guanidine hydrochloride (M (Gdn-HCl)). The {sup 13}C-12 chemical shift at 125.8 ppm in M (NaCl) and 128.1 ppm in M (Gdn-HCl) indicates that the C{sub 13}{double bond}C{sub 14} double bond has a cis configuration, while the {sup 13}C-13 chemical shift at 146.7 ppm in M (NaCl) and 14.57 ppm in M (Gdn-HCl) demonstrates that the Schiff base in unprotonated. The principal values of the chemical shift tensor of the {sup 13}C-5 resonance in both M (NaCl) and M (Gdn-HCl) are consistent with a 6-s-trans structure and a negative protein charge localized near C-5 as was observed in dark adapted bR. The {approximately}5 ppm upfield shift of the {sup 13}C-5 M resonance relative to {sup 13}C-5 bR{sub 568} and bR{sub 548} is attributed to an unprotonated Schiff base in the M chromophore. Of particular interest in this study were the results obtained from {sup 13}C-14 M. In M (NaCl), a dramatic upfield shift was observed for the {sup 13}C-14 resonance relative to unprotonanted Schiff base model compounds. In contrast, in M (Gdn-HCl) the {sup 13}C-14 resonance was observed at 125.7 ppm. The different {sup 13}C-14 chemical shifts in these two M preparations may be explained by different C{double prime}N configurations of the retinal-lysine Schiff base linkage, namely, syn in NaCl and anti in guanidine hydrochloride.

  2. - and Cross-Polarization 13C NMR Evidence of Alterations in Molecular Composition of Humic Substances Following Afforestation with Eucalypt in Distinct Brazilian Biomes

    NASA Astrophysics Data System (ADS)

    Silva, I. R.; Soares, E. M.; Schmidt-Rohr, K.; Novais, R.; Barros, N.; Fernandes, S.

    2010-12-01

    The effect of planting fast growing tree species on SOM quality in tropical regions has been overlooked. In the present study 13C-NMR approaches were used to evaluate the impact of eucalypt cultivation on humic and fulvic acids molecular composition. The results indicate that the replacement of native vegetation by eucalypt plantations increased the relative contribution of aliphatic groups in HA from soils previously under Atlantic Forest, Grassland, and the Cerrado (Curvelo site only). The same trend was observed for FA, except in the Curvelo site. A trend for degradation and smaller contribution of O-alkyl C (carbohydrates) in HA was observed in soils under eucalyptus in Atlantic Forest and Cerrado. For FA such decreases were seen in Cerrado and Grassland biomes after eucalypt planting. In the area cultivated with pasture in the Atlantic Forest biome and in the Grassland soil, the largest contributions of lignin-derived compounds were detected in HA. The HA from the Cerrado at the Curvelo site, where the woody vegetation is virtually devoid of grassy species, showed the lowest intensity of lignin signal then those from the Cerrado sensu stricto in Itacambira, where grass species are more abundant. At our study sites, charred material are most likely derived from burning of the native vegetation, as naturally occurs in the Cerrado region, or anthropogenic fires in the Grassland biome. Burning of harvest residues in eucalypt fields was also a common practice in the early rotations. The replacement of native vegetation by eucalypt plantations increases the relative contribution of nonpolar alkyl groups in HA from soils previously under Atlantic Forest, Grassland, and the Cerrado (Curvelo site only) biomes. There is evidence of substantial contribution of lignin-derived C to HA and FA, especially in sites planted with Brachiaria sp pastures. Eucalypt introduction decreases the relative contribution of carbohydrates in HA and FA. 13C DP/MAS NMR functional groups in

  3. 13C NMR and fluorescence analysis of tryptophan dynamics in wild-type and two single-Trp variants of Escherichia coli thioredoxin.

    PubMed Central

    Kemple, M D; Yuan, P; Nollet, K E; Fuchs, J A; Silva, N; Prendergast, F G

    1994-01-01

    The rotational motion of tryptophan side chains in oxidized and reduced wild-type (WT) Escherichia coli thioredoxin and in two single-tryptophan variants of E. coli thioredoxin was studied in solution in the temperature range 20-50 degrees C from 13C-NMR relaxation rate measurements at 75.4 and 125.7 MHz and at 20 degrees C from steady-state and time-resolved trp fluorescence anisotropy measurements. Tryptophan enriched with 13C at the delta 1 and epsilon 3 sites of the indole ring was incorporated into WT thioredoxin and into two single-trp mutants, W31F and W28F, in which trp-28 or trp-31 of WT thioredoxin was replaced, respectively, with phenylalanine. The NMR relaxation data were interpreted using the Lipari and Szabo "model-free" approach (G. Lipari and A. Szabo. 1982. J. Amer. Chem. Soc. 104:4546-4559) with trp steady-state anisotropy data included for the variants at 20 degrees C. Values for the correlation time for the overall rotational motion (tau m) from NMR of oxidized and reduced WT thioredoxin at 35 degrees C agree well with those given by Stone et al. (Stone, M. J., K. Chandrasekhar, A. Holmgren, P. E. Wright, and H. J. Dyson. 1993. Biochemistry. 32:426-435) from 15N NMR relaxation rates, and the dependence of tau m on viscosity and temperature was in accord with the Stokes-Einstein relationship. Order parameters (S2) near 1 were obtained for the trp side chains in the WT proteins even at 50 degrees C. A slight increase in the amplitude of motion (decrease in S2) of trp-31, which is near the protein surface, but not of trp-28, which is partially buried in the protein matrix, was observed in reduced relative to oxidized WT thioredoxin. For trp-28 in W31F, order parameters near 1 (S2 > or = 0.8) at 20 degrees C were found, whereas trp-31 in W28F yielded the smallest order parameters (S2 approximately 0.6) of any of the cases. Analysis of time-resolved anisotropy decays in W28F and W31F yielded S2 values in good agreement with NMR, but gave tau m values

  4. Comparison of different theory models and basis sets in the calculations of structures and 13C NMR spectra of [Pt(en)(CBDCA-O, O')], an analogue of the antitumor drug carboplatin.

    PubMed

    Gao, Hongwei; Wei, Xiujuan; Liu, Xuting; Yan, Tingxia

    2010-03-25

    Comparisons of various density functional theory (DFT) methods at different basis sets in predicting the molecular structures and (13)C NMR spectra for [Pt(en)(CBDCA-O, O')], an analogue of the antitumor drug carboplatin, are reported. DFT methods including B3LYP, B3PW91, mPW1PW91, PBE1PBE, BPV86, PBEPBE, and LSDA are examined. Different basis sets including LANL2DZ, SDD, LANL2MB, CEP-4G, CEP-31G, and CEP-121G are also considered. It is remarkable that the LSDA/SDD level is clearly superior to all of the remaining density functional methods in predicting the structure of [Pt(en)(CBDCA-O, O')]. The results also indicate that the B3LYP/SDD level is the best to predict (13)C NMR spectra for [Pt(en)(CBDCA-O, O')] among all DFT methods.

  5. The influence of membrane electrode assembly water content on the performance of a polymer electrolyte membrane fuel cell as investigated by 1H NMR microscopy.

    PubMed

    Feindel, Kirk W; Bergens, Steven H; Wasylishen, Roderick E

    2007-04-21

    The relation between the performance of a self-humidifying H(2)/O(2) polymer electrolyte membrane fuel cell and the amount and distribution of water as observed using (1)H NMR microscopy was investigated. The integrated (1)H NMR image signal intensity (proportional to water content) from the region of the polymer electrolyte membrane between the catalyst layers was found to correlate well with the power output of the fuel cell. Several examples are provided which demonstrate the sensitivity of the (1)H NMR image intensity to the operating conditions of the fuel cell. Changes in the O(2)(g) flow rate cause predictable trends in both the power density and the image intensity. Higher power densities, achieved by decreasing the resistance of the external circuit, were found to increase the water in the PEM. An observed plateau of both the power density and the integrated (1)H NMR image signal intensity from the membrane electrode assembly and subsequent decline of the power density is postulated to result from the accumulation of H(2)O(l) in the gas diffusion layer and cathode flow field. The potential of using (1)H NMR microscopy to obtain the absolute water content of the polymer electrolyte membrane is discussed and several recommendations for future research are provided.

  6. Use of {sup 13}C NMR to assess the biodegradation of 1-{sup 13}C-labeled acenaphthene in the presence of creosote polynuclear hydrocarbons (PAHs) and naphthalene by mixed bacterial cultures

    SciTech Connect

    Selifonov, S.A.; Bortiatynski, J.M.; Nanny, M.A.; Hatcher, P.G.

    1996-10-01

    1-{sup 13}C-acenaphthene mixed with creosote PAH`s or naphthalene was incubated with bacterial strains known to degrade naphthalene, phenanthrene and acenaphthene. After incubation, the reaction mixtures were extracted with organic solvent, and the biodegradation products were identified by {sup 13}C NMR. An accumulation of intermediate degradation products was identified and attributed to the non-specific action of naphthalene catabolic pathways of the mixed bacterial cultures. An acenaphthene degrading strain, Pseudomonas sp. strain A2279 was added to the nixed bacterial cultures to minimize the formation of the observed dead-end products. The {sup 13}C NMR spectra obtained from the experiments in which strain A2279 was present clearly showed the complete biodegradation of 1-{sup 13}C-acenaphthene without the accumulation of {sup 13}C-labeled products. This set of experiments clearly demonstrates the utility of {sup 13}C NMR as an effective tool for the assessment of the biodegradation of PAH`s such as 1-{sup 13}C-acenaphthene by various microbial strains.

  7. An approach to the simultaneous quantitative analysis of metabolites in table wines by (1)H NMR self-constructed three-dimensional spectra.

    PubMed

    Li, Bao Qiong; Xu, Min Li; Wang, Xue; Zhai, Hong Lin; Chen, Jing; Liu, Jin Jin

    2017-02-01

    Wine consists of several hundred components with different concentrations, including water, ethanol, glycerol, organic acids and sugars. Accurate quantification of target compounds in such complex samples is a difficult task based on conventional (1)H NMR spectra due to some challenges. In this paper, the three-dimensional spectrum was constructed firstly by simply repeating (1)H NMR spectrum itself so as to extract the features of target compounds by Tchebichef moment method. A proof-of-concept model system, the determination of five metabolites in wines was utilized to evaluate the performance of the proposed strategy. The results indicate that the proposed approach can provide accurate and reliable concentration predictions, probably the best results ever achieved using PLS and interval-PLS methods. Our novel strategy has not only good performance but also does not require laborious multi-step and subjective pretreatments. Therefore, it is expected that the proposed method could extend the application of conventional (1)H NMR.

  8. Selective Detection of 1H NMR Resonances of CH n Groups Using a Heteronuclear Maximum-Quantum Filter and Pulsed Field Gradients

    NASA Astrophysics Data System (ADS)

    Liu, M.; Farrant, R. D.; Nicholson, J. K.; Lindon, J. C.

    A number of approaches are described for the provision of separate one-dimensional 1H NMR spectra of CH, CH 2, and CH 3 groups utilizing the natural-abundance 13C spins and based upon the selection of the maximum multiple-quantum coherences of the various groups, This sequence is termed edited maximum-quantum proton spectroscop y (MAXY) spectroscopy, The replacement of phase cycling with the application of z magnetic field gradient pulses is also demonstrated, The editing approach is demonstrated using the 1H NMR spectrum of dexamethasone in DMSO- d6 solution, Extension to a complex mixture biofluid is exemplified by the CH 3-only 1H NMR spectrum of human seminal plasma. This aid to the assignment of endogenous metabolite resonances is demonstrated to result in dramatic spectral simplification.

  9. Solution structure of Ln(III) complexes with macrocyclic ligands through theoretical evaluation of 1H NMR contact shifts.

    PubMed

    Rodríguez-Rodríguez, Aurora; Esteban-Gómez, David; de Blas, Andrés; Rodríguez-Blas, Teresa; Botta, Mauro; Tripier, Raphaël; Platas-Iglesias, Carlos

    2012-12-17

    Herein, we present a new approach that combines DFT calculations and the analysis of Tb(III)-induced (1)H NMR shifts to quantitatively and accurately account for the contact contribution to the paramagnetic shift in Ln(III) complexes. Geometry optimizations of different Gd(III) complexes with macrocyclic ligands were carried out using the hybrid meta-GGA TPSSh functional and a 46 + 4f(7) effective core potential (ECP) for Gd. The complexes investigated include [Ln(Me-DODPA)](+) (H(2)Me-DODPA = 6,6'-((4,10-dimethyl-1,4,7,10-tetraazacyclododecane-1,7-diyl)bis(methylene))dipicolinic acid, [Ln(DOTA)(H(2)O)](-) (H(4)DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate), [Ln(DOTAM)(H(2)O)](3+) (DOTAM = 1,4,7,10- tetrakis[(carbamoyl)methyl]-1,4,7,10-tetraazacyclododecane), and related systems containing pyridyl units (Ln = Gd, Tb). Subsequent all-electron relativistic calculations based on the DKH2 approximation, or small-core ECP calculations, were used to compute the (1)H hyperfine coupling constants (HFCCs) at the ligand nuclei (A(iso) values). The calculated A(iso) values provided direct access to contact contributions to the (1)H NMR shifts of the corresponding Tb(III) complexes under the assumption that Gd and Tb complexes with a given ligand present similar HFCCs. These contact shifts were used to obtain the pseudocontact shifts, which encode structural information as they depend on the position of the nucleus with respect to the lanthanide ion. An excellent agreement was observed between the experimental and calculated pseudocontact shifts using the DFT-optimized geometries as structural models of the complexes in solution, which demonstrates that the computational approach used provides (i) good structural models for the complexes, (ii) accurate HFCCs at the ligand nuclei. The methodology presented in this work can be classified in the context of model-dependent methods, as it relies on the use of a specific molecular structure obtained from DFT

  10. Self-diffusion and interactions in mixtures of imidazolium bis(mandelato)borate ionic liquids with polyethylene glycol: (1) H NMR study.

    PubMed

    Filippov, Andrei; Azancheev, Nail; Taher, Mamoun; Shah, Faiz Ullah; Rabét, Pauline; Glavatskih, Sergei; Antzutkin, Oleg N

    2015-07-01

    We used (1) H nuclear magnetic resonance pulsed-field gradient to study the self-diffusion of polyethylene glycol (PEG) and ions in a mixture of PEG and imidazolium bis(mandelato)borate ionic liquids (ILs) at IL concentrations from 0 to 10 wt% and temperatures from 295 to 370 K. PEG behaves as a solvent for these ILs, allowing observation of separate lines in (1) H NMR spectra assigned to the cation and anion as well as to PEG. The diffusion coefficients of PEG, as well as the imidazolium cation and bis(mandelato)borate (BMB) anion, differ under all experimental conditions tested. This demonstrates that the IL in the mixture is present in at least a partially dissociated state, while the lifetimes of the associated states of the ions and ions with PEG are less than ~30 ms. Generally, increasing the concentration of the IL leads to a decrease in the diffusion coefficients of PEG and both ions. The diffusion coefficient of the anion is less than that of the cation; the molecular mass dependence of diffusion of ions can be described by the Stokes-Einstein model. NMR chemical shift alteration analysis showed that the presence of PEG changes mainly the chemical shifts of protons belonging to imidazole ring of the cation, while chemical shifts of protons of anions and PEG remain unchanged. This demonstrated that the imidazolium cation interacts mainly with PEG, which most probably occurs through the oxygen of PEG and the imidazole ring. The BMB anion does not strongly interact with PEG, but it may be indirectly affected by PEG through interaction with the cation, which directly interacts with PEG.

  11. Detection of Butter Adulteration with Lard by Employing (1)H-NMR Spectroscopy and Multivariate Data Analysis.

    PubMed

    Fadzillah, Nurrulhidayah Ahmad; Man, Yaakob bin Che; Rohman, Abdul; Rosman, Arieff Salleh; Ismail, Amin; Mustafa, Shuhaimi; Khatib, Alfi

    2015-01-01

    The authentication of food products from the presence of non-allowed components for certain religion like lard is very important. In this study, we used proton Nuclear Magnetic Resonance ((1)H-NMR) spectroscopy for the analysis of butter adulterated with lard by simultaneously quantification of all proton bearing compounds, and consequently all relevant sample classes. Since the spectra obtained were too complex to be analyzed visually by the naked eyes, the classification of spectra was carried out.The multivariate calibration of partial least square (PLS) regression was used for modelling the relationship between actual value of lard and predicted value. The model yielded a highest regression coefficient (R(2)) of 0.998 and the lowest root mean square error calibration (RMSEC) of 0.0091% and root mean square error prediction (RMSEP) of 0.0090, respectively. Cross validation testing evaluates the predictive power of the model. PLS model was shown as good models as the intercept of R(2)Y and Q(2)Y were 0.0853 and -0.309, respectively.

  12. Comparative study of the complex forming ability and enantioselectivity of cyclodextrin polymers by CE and 1H NMR.

    PubMed

    Danel, Cécile; Azaroual, Nathalie; Chavaria, Cédric; Odou, Pascal; Martel, Bernard; Vaccher, Claude

    2013-02-15

    The interactions between nine drugs (baclofen, bupivacaine, chlorpheniramine, ketoconazole, paliperidone, promethazine, propranolol, risperidone and verapamil) and six cyclodextrins (α-CD, β-CD, γ-CD, HP-β-CD, HP-γ-CD and Me-β-CD) or six polymers of cyclodextrins (polyα-CD, polyβ-CD, polyγ-CD, polyHP-β-CD, polyHP-γ-CD and polyMe-β-CD) were studied by affinity capillary electrophoresis and/or (1)H NMR at pH 2.5. An exhaustive qualitative study was performed through the determination of the retardation factor. Then, four compounds and both β-CD and polyβ-CD were selected for the quantitative study of the interactions at pH 2.5 and 7.0. By comparing the results obtained with the β-CD and polyβ-CD, it appears that the apparent binding constants are up to five times higher with the polymer. The 2D-NMR results seem to indicate that the structure of the polymeric network favours the inclusion of the guest in the hydrophobic cavity of the CD units. Moreover, the poly-CDs have shown very high enantioselective abilities at both pH.

  13. 1H NMR studies distinguish the water soluble metabolomic profiles of untransformed and RAS-transformed cells

    PubMed Central

    Marks, Vered; Munoz, Anisleidys; Rai, Priyamvada

    2016-01-01

    Metabolomic profiling is an increasingly important method for identifying potential biomarkers in cancer cells with a view towards improved diagnosis and treatment. Nuclear magnetic resonance (NMR) provides a potentially noninvasive means to accurately characterize differences in the metabolomic profiles of cells. In this work, we use 1H NMR to measure the metabolomic profiles of water soluble metabolites extracted from isogenic control and oncogenic HRAS-, KRAS-, and NRAS-transduced BEAS2B lung epithelial cells to determine the robustness of NMR metabolomic profiling in detecting differences between the transformed cells and their untransformed counterparts as well as differences among the RAS-transformed cells. Unique metabolomic signatures between control and RAS-transformed cell lines as well as among the three RAS isoform-transformed lines were found by applying principal component analysis to the NMR data. This study provides a proof of principle demonstration that NMR-based metabolomic profiling can robustly distinguish untransformed and RAS-transformed cells as well as cells transformed with different RAS oncogenic isoforms. Thus, our data may potentially provide new diagnostic signatures for RAS-transformed cells. PMID:27330862

  14. Solubilization of flurbiprofen within non-ionic Tween 20 surfactant micelles: a 19F and 1H NMR study.

    PubMed

    Saveyn, Pieter; Cocquyt, Ellen; Zhu, Wuxin; Sinnaeve, Davy; Haustraete, Katrien; Martins, José C; Van der Meeren, Paul

    2009-07-14

    The solubilization of the poorly water soluble anti-inflammatory drug flurbiprofen in non-ionic Tween 20 surfactant micellar solutions was studied by both (19)F and (1)H NMR spectroscopy in an acidic environment. These non-destructive techniques allowed us to investigate the effect of temperature cycling in situ. Using (19)F NMR, an increased solubilisation capacity was observed as the temperature increased. This effect became more pronounced above the cloud point, which was reduced by more than 30 degrees C in the presence of an excess of flurbiprofen. Upon clouding, peak splitting was observed in the (19)F spectrum, which indicates that two pools of solubilised flurbiprofen exist that are in slow exchange on the NMR frequency timescale. The clouding and solubilization processes were found to be reversible, albeit with slow kinetics. Based on chemical shift differences of both Tween 20 and flurbiprofen, as well as NOESY experiments, the flurbiprofen was found to be accumulated within the palisade layer of the Tween 20 micelles.

  15. (1)H NMR-based DS determination of barley starch sulfates prepared in 1-allyl-3-methylimidazolium chloride.

    PubMed

    Kärkkäinen, Johanna; Wik, Tiia-Riikka; Niemelä, Matti; Lappalainen, Katja; Joensuu, Päivi; Lajunen, Marja

    2016-01-20

    The use of natural resources in a development of products and materials is currently increasing. Starch is one of the investigated resources due to its bioavailability, biodegradability, safety and affordability. In this study, native barley starch was sulfated using a SO3-pyridine complex. The reaction was carried out for the first time using 1-allyl-3-methylimidazolium chloride ionic liquid, an excellent solvent for the starch modification. Reaction conditions (temperature, time and amount of the reagent) were studied using an experimental design. Starch sulfates with the degree of substitution (DS) 1.37 were obtained when the reaction was carried out at 40 °C for 75 min with 4:1 molar ratio of SO3-pyridine complex:anhydroglucose unit. The determination of DS was based on (1)H NMR instead of elemental analysis, which showed overestimated DS values in this study. Starch sulfates were analyzed with FTIR and HPLC, which showed that products contained small and large sulfated molecules.

  16. (1)H NMR-based metabolomics of Daphnia magna responses after sub-lethal exposure to triclosan, carbamazepine and ibuprofen.

    PubMed

    Kovacevic, Vera; Simpson, André J; Simpson, Myrna J

    2016-09-01

    Pharmaceuticals and personal care products are a class of emerging contaminants that are present in wastewater effluents, surface water, and groundwater around the world. There is a need to determine rapid and reliable bioindicators of exposure and the toxic mode of action of these contaminants to aquatic organisms. (1)H nuclear magnetic resonance (NMR)-based metabolomics in combination with multivariate statistical analysis was used to determine the metabolic profile of Daphnia magna after exposure to a range of sub-lethal concentrations of triclosan (6.25-100μg/L), carbamazepine (1.75-14mg/L) and ibuprofen (1.75-14mg/L) for 48h. Sub-lethal triclosan exposure suggested a general oxidative stress condition and the branched-chain amino acids, glutamine, glutamate, and methionine emerged as potential bioindicators. The aromatic amino acids, serine, glycine and alanine are potential bioindicators for sub-lethal carbamazepine exposure that may have altered energy metabolism. The potential bioindicators for sub-lethal ibuprofen exposure are serine, methionine, lysine, arginine and leucine, which showed a concentration-dependent response. The differences in the metabolic changes were related to the dissimilar modes of toxicity of triclosan, carbamazepine and ibuprofen. (1)H NMR-based metabolomics gave an improved understanding of how these emerging contaminants impact the keystone species D. magna.

  17. MAS (1)H NMR Probes Freezing Point Depression of Water and Liquid-Gel Phase Transitions in Liposomes.

    PubMed

    Mandal, Abhishek; van der Wel, Patrick C A

    2016-11-01

    The lipid bilayer typical of hydrated biological membranes is characterized by a liquid-crystalline, highly dynamic state. Upon cooling or dehydration, these membranes undergo a cooperative transition to a rigidified, more-ordered, gel phase. This characteristic phase transition is of significant biological and biophysical interest, for instance in studies of freezing-tolerant organisms. Magic-angle-spinning (MAS) solid-state NMR (ssNMR) spectroscopy allows for the detection and characterization of the phase transitions over a wide temperature range. In this study we employ MAS (1)H NMR to probe the phase transitions of both solvent molecules and different hydrated phospholipids, including tetraoleoyl cardiolipin (TOCL) and several phosphatidylcholine lipid species. The employed MAS NMR sample conditions cause a previously noted substantial reduction in the freezing point of the solvent phase. The effect on the solvent is caused by confinement of the aqueous solvent in the small and densely packed MAS NMR samples. In this study we report and examine how the freezing point depression also impacts the lipid phase transition, causing a ssNMR-observed reduction in the lipids' melting temperature (Tm). The molecular underpinnings of this phenomenon are discussed and compared with previous studies of membrane-associated water phases and the impact of membrane-protective cryoprotectants.

  18. 1H-NMR metabolic profiling of cerebrospinal fluid in patients with complex regional pain syndrome-related dystonia.

    PubMed

    Meissner, Axel; van der Plas, Anton A; van Dasselaar, Nick T; Deelder, André M; van Hilten, Jacobus J; Mayboroda, Oleg A

    2014-01-01

    In complex regional pain syndrome (CRPS)-related dystonia, compelling evidence points to the involvement of the central nervous system, but the underpinning pathobiology is still unclear. Thus, to enable a hypothesis-free, unbiased view of the problem and to obtain new insight into the pathobiology of dystonia in CRPS, we applied an exploratory metabolomics analysis of cerebrospinal fluid (CSF) of patients with CRPS-related dystonia. (1)H-NMR spectroscopy in combination with multivariate modeling were used to investigate metabolic profiles of a total of 105 CSF samples collected from patients with CRPS-related dystonia and controls. We found a significantly different metabolic profile of CSF in CRPS patients compared to controls. The differences were already reflected in the first two principal components of the principal component analysis model, which is an indication that the variance associated with CRPS is stronger than variance caused by such classical confounders as gender, age, or individual differences. A supervised analysis generated a strong model pinpointing the most important metabolites contributed to the metabolic signature of patients with CRPS-related dystonia. From the set of identified discriminators, the most relevant metabolites were 2-keto-isovalerate, glucose, glutamine, and lactate, which all showed increased concentrations, and urea, which showed decreased concentration in CRPS subjects. Our findings point at a catabolic state in chronic CRPS patients with dystonia that is likely associated with inflammation.

  19. 1H NMR study of the hetero-association of flavin-mononucleotide with mutagenic dyes: ethidium bromide and proflavine

    NASA Astrophysics Data System (ADS)

    Evstigneev, M. P.; Mukhina, Yu. V.; Davies, D. B.

    The hetero-association of the vitamin B2 derivative, flavin-mononucleotide (FMN), with a mutagenic dye, ethidium bromide (EB) or proflavine (PF), has been studied by 1D and 2D 500 MHz 1H NMR spectroscopy. The variations of proton chemical shifts of both the vitamin and dye as a function of concentration and temperature were analysed in terms of the structural and thermodynamical properties of the FMN-EB and FMN-PF complexes in solution. The structures of the complexes were also investigated by observed intermolecular ROE contacts and molecular mechanics calculations. The results show that the 1 : 1 hetero-association complexes in solution are more stable than the self-association complexes, which is consistent with formation of an intermolecular hydrogen-bond in the hetero-complexes of FMN-EB and FMN-PF. Hence it is possible that the toxicity of aromatic molecules such as EB and PF may be reduced in vitro by the presence of FMN, partly because of the known antimutagenic action of FMN and partly because it has been shown in this work that there is an effective intermolecular association between the mutagens and the vitamin.

  20. Optical, electrochemical, and 1H NMR characteristics of Mono-, Bi-, and tetranuclear cyclopalladated complexes with 4,4'-bipyridyl

    NASA Astrophysics Data System (ADS)

    Panova, A. G.; Puzyk, M. V.; Farus, O. A.; Balashev, K. P.

    2011-03-01

    The [Pd(C∧N)(4,4'-bpy)Cl], [Pd(C∧N)NO3]2(μ-4,4'-bpy) and [Pd(C∧N)(μ-4,4'-bpy)]4(NO3)4 complexes (C∧N- are deprotonated forms of 2-phenylpyridine (ppy), 2-(2''-thienyl)pyridine (tpy), and 2-phenylbenzothiazole (bt); bpy is 4,4' bipyridyl) are synthesized and characterized by 1H NMR spectroscopy, electronic absorption and emission spectroscopy, and cyclic voltammetry. The upfield shifts of the chemical shift of a proton in the ortho-position to the donor carbon atom of the cyclopalladated ligand of complexes (Δδ = -(1.1-1.5) ppm) is assigned to the anisotropic effect of the circular current of the pyridine rings of 4,4'-bipyridyl orthogonal to the coordination plane. The characteristic long-wavelength absorption and phosphorescence bands of the complexes are assigned to the chromophore metal-complex fragment {M(C∧N)}. The quasi-reversible reduction waves of complexes are assigned to the ligand-centered processes of successive electron transfer to the π*-orbitals localized mainly on the coordinated pyridine components of 4,4'-bipyridyl.

  1. Metastatic Melanoma Induced Metabolic Changes in C57BL/6J Mouse Stomach Measured by 1H NMR Spectroscopy

    DOE PAGES

    Hu, M; Wang, Xiliang

    2014-12-05

    Melanoma is a malignant tumor of melanocytes with high capability of invasion and rapid metastasis to other organs. Malignant melanoma is the most common metastatic malignancy found in gastrointestinal tract (GI). To the best of our knowledge, previous studies of melanoma in gastrointestinal tract are all clinical case reports. In this work, 1H NMR-based metabolomics approach is used to investigate the metabolite profiles differences of stomach tissue extracts of metastatic B16-F10 melanoma in C57BL/6J mouse and search for specific metabolite biomarker candidates. Principal Component Analysis (PCA), an unsupervised multivariate data analysis method, is used to detect possible outliers, while Orthogonalmore » Projection to Latent Structure (OPLS), a supervised multivariate data analysis method, is employed to evaluate important metabolites responsible for discriminating the control and the melanoma groups. Both PCA and OPLS results reveal that the melanoma group can be well separated from its control group. Among the 50 identified metabolites, it is found that the concentrations of 19 metabolites are statistically and significantly changed with the levels of O-phosphocholine and hypoxanthine down-regulated while the levels of isoleucine, leucine, valine, isobutyrate, threonine, cadaverine, alanine, glutamate, glutamine, methionine, citrate, asparagine, tryptophan, glycine, serine, uracil, and formate up-regulated in the melanoma group. These significantly changed metabolites are associated with multiple biological pathways and may be potential biomarkers for metastatic melanoma in stomach.« less

  2. Global Metabolic Stress of Isoeffort Continuous and High Intensity Interval Aerobic Exercise: A Comparative (1)H NMR Metabonomic Study.

    PubMed

    Zafeiridis, Andreas; Chatziioannou, Anastasia Chrysovalantou; Sarivasiliou, Haralambos; Kyparos, Antonios; Nikolaidis, Michalis G; Vrabas, Ioannis S; Pechlivanis, Alexandros; Zoumpoulakis, Panagiotis; Baskakis, Constantinos; Dipla, Konstantina; Theodoridis, Georgios A

    2016-12-02

    The overall metabolic/energetic stress that occurs during an acute bout of exercise is proposed to be the main driving force for long-term training adaptations. Continuous and high-intensity interval exercise protocols (HIIE) are currently prescribed to acquire the muscular and metabolic benefits of aerobic training. We applied (1)H NMR-based metabonomics to compare the overall metabolic perturbation and activation of individual bioenergetic pathways of three popular aerobic exercises matched for effort/strain. Nine men performed continuous, long-interval (3 min), and short-interval (30 s) bouts of exercise under isoeffort conditions. Blood was collected before and after exercise. The multivariate PCA and OPLS-DA models showed a distinct separation of pre- and postexercise samples in three protocols. The two models did not discriminate the postexercise overall metabolic profiles of the three exercise types. Analysis focused on muscle bioenergetic pathways revealed an extensive upregulation of carbohydrate-lipid metabolism and the TCA cycle in all three protocols; there were only a few differences among protocols in the postexercise abundance of molecules when long-interval bouts were performed. In conclusion, continuous and HIIE exercise protocols, when performed with similar effort/strain, induce comparable global metabolic response/stress despite their marked differences in work-bout intensities. This study highlights the importance of NMR metabonomics in comprehensive monitoring of metabolic consequences of exercise training in the blood of athletes and exercising individuals.

  3. Metabolite Variation in Lean and Obese Streptozotocin (STZ)-Induced Diabetic Rats via (1)H NMR-Based Metabolomics Approach.

    PubMed

    Abu Bakar Sajak, Azliana; Mediani, Ahmed; Maulidiani; Ismail, Amin; Abas, Faridah

    2016-12-19

    Diabetes mellitus (DM) is considered as a complex metabolic disease because it affects the metabolism of glucose and other metabolites. Although many diabetes studies have been conducted in animal models throughout the years, the pathogenesis of this disease, especially between lean diabetes (ND + STZ) and obese diabetes (OB + STZ), is still not fully understood. In this study, the urine from ND + STZ, OB + STZ, lean/control (ND), and OB + STZ rats were collected and compared by using (1)H NMR metabolomics. The results from multivariate data analysis (MVDA) showed that the diabetic groups (ND + STZ and OB + STZ) have similarities and dissimilarities for a certain level of metabolites. Differences between ND + STZ and OB + STZ were particularly noticeable in the synthesis of ketone bodies, branched-chain amino acid (BCAA), and sensitivity towards the oral T2DM diabetes drug metformin. This finding suggests that the ND + STZ group was more similar to the T1DM model and OB + STZ to the T2DM model. In addition, we also managed to identify several pathways and metabolism aspects shared by obese (OB) and OB + STZ. The results from this study are useful in developing drug target-based research as they can increase understanding regarding the cause and effect of DM.

  4. (1)H NMR-Based Global Metabolic Studies of Pseudomonas aeruginosa upon Exposure of the Quorum Sensing Inhibitor Resveratrol.

    PubMed

    Chen, Tongtong; Sheng, Jiyang; Fu, Yonghong; Li, Minghui; Wang, Junsong; Jia, Ai-Qun

    2017-02-03

    Quorum sensing (QS) is a process of bacterial communication that has been a novel target for drug discovery. Pyocyanin quantification assay confirmed that resveratrol was an effective quorum sensing inhibitor (QSI) against Pseudomonas aeruginosa PAO1. In this study, the global metabolite changes of P. aeruginosa PAO1 exposed to QSI resveratrol were investigated by (1)H NMR spectroscopy. A total of 40 metabolites containing amino acids, organic acid, organic amine, and energy storage compounds were identified. The changed metabolic profile indicated that resveratrol influenced pathways including oxidative stress, protein synthesis, and energy metabolism. Oxidative stress could upregulate the expression of genes related to QS in P. aeruginosa. It suggested that resveratrol could inhibit the QS systems in P. aeruginosa PAO1 by relieving oxidative stress due to its antioxidant activity. On the other hand, resveratrol could attenuate the pathogenicity of P. aeruginosa PAO1 by disturbing the TCA cycle so that anaerobic respiration could suppress the virulence because anaerobiosis could induce the loss of cytotoxicity regulated by QS in P. aeruginosa. These findings deepened our comprehending of the metabolic responses of P. aeruginosa PAO1 to resveratrol and pinpointed the possible underlying mechanism of resveratrol's inhibition effect on QS in P. aeruginosa PAO1.

  5. Application of quantitative 1H-NMR method to determination of gentiopicroside in Gentianae radix and Gentianae scabrae radix.

    PubMed

    Tanaka, Rie; Hasebe, Yuko; Nagatsu, Akito

    2014-07-01

    A quantitative (1)H-NMR method (qHNMR) was used to measure gentiopicroside content in Gentianae radix and Gentianae scabrae radix. Gentiopicroside is a major component of Gentianae radix and Gentianae scabrae radix. The purity of gentiopicroside was calculated from the ratio of the intensity of the H-3 signal at δ 7.44 ppm or the H-8 signal at δ 5.78 ppm in methanol-d 4 of gentiopicroside to that of a hexamethyldisilane (HMD) signal at 0 ppm. The concentration of HMD was corrected with SI traceability by using potassium hydrogen phthalate of certified reference material (CRM) grade. As a result, the gentiopicroside content in two lots of Gentianae radix as determined by qHNMR was found to be 1.76 and 2.17 %, respectively. The gentiopicroside content in two lots of Gentianae scabrae radix was 2.73 and 3.99 %, respectively. We demonstrated that this method is useful for the quantitative analysis of crude drugs.

  6. Gender-Specific Metabolomic Profiling of Obesity in Leptin-Deficient ob/ob Mice by 1H NMR Spectroscopy

    PubMed Central

    Kim, Sang-Woo; Jung, Youngae; Bae, Hyun-Whee; Lee, Daeyoup; Park, Sung Goo; Lee, Chul-Ho; Hwang, Geum-Sook; Chi, Seung-Wook

    2013-01-01

    Despite the numerous metabolic studies on obesity, gender bias in obesity has rarely been investigated. Here, we report the metabolomic analysis of obesity by using leptin-deficient ob/ob mice based on the gender. Metabolomic analyses of urine and serum from ob/ob mice compared with those from C57BL/6J lean mice, based on the 1H NMR spectroscopy in combination with multivariate statistical analysis, revealed clear metabolic differences between obese and lean mice. We also identified 48 urine and 22 serum metabolites that were statistically significantly altered in obese mice compared to lean controls. These metabolites are involved in amino acid metabolism (leucine, alanine, ariginine, lysine, and methionine), tricarbocylic acid cycle and glucose metabolism (pyruvate, citrate, glycolate, acetoacetate, and acetone), lipid metabolism (cholesterol and carnitine), creatine metabolism (creatine and creatinine), and gut-microbiome-derived metabolism (choline, TMAO, hippurate, p-cresol, isobutyrate, 2-hydroxyisobutyrate, methylamine, and trigonelline). Notably, our metabolomic studies showed distinct gender variations. The obese male mice metabolism was specifically associated with insulin signaling, whereas the obese female mice metabolism was associated with lipid metabolism. Taken together, our study identifies the biomarker signature for obesity in ob/ob mice and provides biochemical insights into the metabolic alteration in obesity based on gender. PMID:24098417

  7. Benzocaine complexation with p-sulfonic acid calix[n]arene: experimental ((1) H-NMR) and theoretical approaches.

    PubMed

    Arantes, Lucas M; Varejão, Eduardo V V; Pelizzaro-Rocha, Karin J; Cereda, Cíntia M S; de Paula, Eneida; Lourenço, Maicon P; Duarte, Hélio A; Fernandes, Sergio A

    2014-05-01

    The aim of this work was to study the interaction between the local anesthetic benzocaine and p-sulfonic acid calix[n]arenes using NMR and theoretical calculations and to assess the effects of complexation on cytotoxicity of benzocaine. The architectures of the complexes were proposed according to (1) H NMR data (Job plot, binding constants, and ROESY) indicating details on the insertion of benzocaine in the cavity of the calix[n]arenes. The proposed inclusion compounds were optimized using the PM3 semiempirical method, and the electronic plus nuclear repulsion energy contributions were performed at the DFT level using the PBE exchange/correlation functional and the 6-311G(d) basis set. The remarkable agreement between experimental and theoretical approaches adds support to their use in the structural characterization of the inclusion complexes. In vitro cytotoxic tests showed that complexation intensifies the intrinsic toxicity of benzocaine, possibly by increasing the water solubility of the anesthetic and favoring its partitioning inside of biomembranes.

  8. Metabolite signatures in hydrophilic extracts of mouse lungs exposed to cigarette smoke revealed by 1H NMR metabolomics investigation

    DOE PAGES

    Hu, Jian Z.; Wang, Xuan; Feng, Ju; ...

    2015-05-12

    Herein, 1H-NMR metabolomics are carried out to evaluate the changes of metabolites in lungs of mice exposed to cigarette smoke. It is found that the concentrations of adenosine derivatives (i.e. ATP, ADP and AMP), inosine and uridine are significantly fluctuated in the lungs of mice exposed to cigarette smoke compared with those of controls regardless the mouse is obese or regular weight. The decreased ATP, ADP, AMP and elevated inosine predict that the deaminases in charge of adenosine derivatives to inosine derivatives conversion are altered in lungs of mice exposed to cigarette smoke. Transcriptional analysis reveals that the concentrations ofmore » adenosine monophosphate deaminase and adenosine deaminase are different in the lungs of mice exposed to cigarette smoke, confirming the prediction from metabolomics studies. We also found, for the first time, that the ratio of glycerophosphocholine (GPC) to phosphocholine (PC) is significantly increased in the lungs of obese mice compared with regular weight mice. The ratio of GPC/PC is further elevated in the lungs of obese group by cigarette smoke exposure. Since GPC/PC ratio is a known biomarker for cancer, these results may suggest that obese group is more susceptible to lung cancer when exposed to cigarette smoke.« less

  9. Quantitative determination of caffeine, formic acid, trigonelline and 5-(hydroxymethyl)furfural in soluble coffees by 1H NMR spectrometry.

    PubMed

    del Campo, Gloria; Berregi, Iñaki; Caracena, Raúl; Zuriarrain, Juan

    2010-04-15

    A quantitative method for the determination of caffeine, formic acid, trigonelline and 5-(hydroxymethyl)furfural (5-HMF) in soluble coffees by applying the proton nuclear magnetic resonance technique ((1)H NMR) is proposed. Each of these compounds records a singlet signal at the 7.6-9.5 ppm interval of the spectrum, and its area is used to determine the concentration. 3-(Trimethylsilyl)-2,2,3,3-tetradeuteropropionic acid is added in an exact known concentration as a reference for delta=0.00 ppm and as an internal standard. The method is applied to commercial soluble coffees and satisfactorily compared with results obtained by standard methods. The limits of detection and the coefficients of variation (N=10) are, respectively, 1.32 mg/g of solid product and 4.2% for caffeine, 0.45 mg/g and 2.6% for formic acid, 0.58 mg/g and 2.4% for trigonelline, and 0.30 mg/g and 7.3% for 5-HMF. The described method is direct and no previous derivatization is needed.

  10. sup 1 H NMR study of renal trimethylamine responses to dehydration and acute volume loading in man

    SciTech Connect

    Avison, M.J.; Rothman, D.L.; Nixon, T.W.; Long, W.S.; Siegel, N.J. )

    1991-07-15

    The authors have used volume-localized {sup 1}H NMR spectroscopy to detect and measure changes in medullary trimethylamines (TMAs) in the human kidney in vivo. Localized water-suppressed {sup 1}H spectra were collected from a volume of interest located within the renal medulla by using a stimulated echo-based localization scheme. The principal resonances in the medullary {sup 1}H spectrum were residual water, lipid, and TMAs. The TMA line width was 7-15 Hz before filtering, and the signal-to-noise ratio was 40:1. In four normal volunteers, 15 hr of dehydration led to a significant increase in urine ismolality and decrease in body weight and an increase in medullary TMAs. A subsequent water load caused a transient water diuresis, a return to euvolemic body weight, and a significant reduction in medullary TMAs within 4 hr. These results suggest that TMAs may play an osmoregulatory role in the medulla of the normal human kidney.

  11. Metabolic Discrimination of Catharanthus roseus Leaves Infected by Phytoplasma Using 1H-NMR Spectroscopy and Multivariate Data Analysis1

    PubMed Central

    Choi, Young Hae; Tapias, Elisabet Casas; Kim, Hye Kyong; Lefeber, Alfons W.M.; Erkelens, Cornelis; Verhoeven, Jacobus Th.J.; Brzin, Jernej; Zel, Jana; Verpoorte, Robert

    2004-01-01

    A comprehensive metabolomic profiling of Catharanthus roseus L. G. Don infected by 10 types of phytoplasmas was carried out using one-dimensional and two-dimensional NMR spectroscopy followed by principal component analysis (PCA), an unsupervised clustering method requiring no knowledge of the data set and used to reduce the dimensionality of multivariate data while preserving most of the variance within it. With a combination of these techniques, we were able to identify those metabolites that were present in different levels in phytoplasma-infected C. roseus leaves than in healthy ones. The infection by phytoplasma in C. roseus leaves causes an increase of metabolites related to the biosynthetic pathways of phenylpropanoids or terpenoid indole alkaloids: chlorogenic acid, loganic acid, secologanin, and vindoline. Furthermore, higher abundance of Glc, Glu, polyphenols, succinic acid, and Suc were detected in the phytoplasma-infected leaves. The PCA of the 1H-NMR signals of healthy and phytoplasma-infected C. roseus leaves shows that these metabolites are major discriminating factors to characterize the phytoplasma-infected C. roseus leaves from healthy ones. Based on the NMR and PCA analysis, it might be suggested that the biosynthetic pathway of terpenoid indole alkaloids, together with that of phenylpropanoids, is stimulated by the infection of phytoplasma. PMID:15286294

  12. 1H NMR Spectroscopy and Multivariate Analysis of Monovarietal EVOOs as a Tool for Modulating Coratina-Based Blends

    PubMed Central

    Del Coco, Laura; De Pascali, Sandra Angelica; Fanizzi, Francesco Paolo

    2014-01-01

    Coratina cultivar-based olives are very common among 100% Italian extra virgin olive oils (EVOOs). Often, the very spicy character of this cultivar, mostly due to the high polyphenols concentration, requires blending with other “sweetener” oils. In this work, monovarietal EVOO samples from the Coratina cultivar (Apulia, Italy) were investigated and compared with monovarietal EVOO from native or recently introduced Apulian (Italy) cultivars (Ogliarola Garganica, Ogliarola Barese, Cima di Mola, Peranzana, Picholine), from Calabria (Italy) (Carolea and Rossanese) and from other Mediterranean countries, such as Spain (Picual) and Greece (Kalamata and Koroneiki) by 1H NMR spectroscopy and multivariate analysis (principal component analysis (PCA)). In this regard, NMR signals could allow a first qualitative evaluation of the chemical composition of EVOO and, in particular, of its minor component content (phenols and aldehydes), an intrinsic behavior of EVOO taste, related to the cultivar and geographical origins. Moreover, this study offers an opportunity to address blended EVOOs tastes by using oils from a specific region or country of origin. PMID:28234316

  13. (1)H NMR based metabolomics approach to study the toxic effects of herbicide butachlor on goldfish (Carassius auratus).

    PubMed

    Xu, Hua-Dong; Wang, Jun-Song; Li, Ming-Hui; Liu, Yan; Chen, Ting; Jia, Ai-Qun

    2015-02-01

    Butachlor, one of the most widely used herbicides in agriculture, has been reported with high ecotoxicity to aquatic plants and animals. In this study, a (1)H NMR based metabolomics approach combined with histopathological examination and biochemical assays was applied to comprehensively investigate the toxic effects of butachlor on four important organs (gill, brain, liver and kidney) of goldfish (Carassius auratus) for the first time. After 10 days' butachlor exposure at two dosages of 3.2 and 0.64 μmol/L, fish tissues (gill, brain, liver and kidney) and serum were collected. Histopathological inspection revealed severe impairment of gill filaments and obvious cellular edema in livers and kidneys. The increase of glutathione peroxidase (GSH-Px) activity in gill and methane dicarboxylic aldehyde (MDA) level in four tissues reflected the disturbance of antioxidative system in the intoxicated goldfish. Serum lactate dehydrogenase (LDH) activity and creatinine (CRE) level were increased in butachlor exposure groups, suggesting liver and kidney injuries induced by butachlor. Orthogonal signal correction partial least-squares discriminant analysis (OSC-PLS-DA) of NMR profiles disclosed metabolic changes that were related to the toxic effects of butachlor including oxidative stress, disorder of energy metabolism and amino acids metabolism, and disturbance of neurotransmitter balance in butachlor exposed goldfish. This integrated metabolomics approach provided a molecular basis underlying the toxicity of butachlor and demonstrated that metabolomics was a powerful and highly effective approach to elucidate the toxicity and underlying mechanisms of herbicides and pesticides, applicable for their risk assessment.

  14. Interaction of phenylbutazone and colchicine in binding to serum albumin in rheumatoid therapy: 1H NMR study

    NASA Astrophysics Data System (ADS)

    Maciążek-Jurczyk, M.; Sułkowska, A.; Bojko, B.; Równicka-Zubik, J.; Sułkowski, W. W.

    2009-09-01

    The monitoring of drug concentration in blood serum is necessary in multi-drug therapy. Mechanism of drug binding with serum albumin (SA) is one of the most important factors which determine drug concentration and its transport to the destination tissues. In rheumatoid diseases drugs which can induce various adverse effects are commonly used in combination therapy. Such proceeding may result in the enhancement of those side effects due to drug interaction. Interaction of phenylbutazone and colchicine in binding to serum albumin and competition between them in gout has been studied by proton nuclear magnetic resonance ( 1H NMR) technique. The aim of the study was to determine the low affinity binding sites, the strength and kind of interaction between serum albumin and drugs used in combination therapy. The study of competition between phenylbutazone and colchicine in binding to serum albumin points to the change of their affinity to serum albumin in the ternary systems. This should be taken into account in multi-drug therapy. This work is a subsequent part of the spectroscopic study on Phe-COL-SA interactions [A. Sułkowska, et al., J. Mol. Struct. 881 (2008) 97-106].

  15. 1H NMR-based metabolic profiling reveals the effects of fluoxetine on lipid and amino acid metabolism in astrocytes.

    PubMed

    Bai, Shunjie; Zhou, Chanjuan; Cheng, Pengfei; Fu, Yuying; Fang, Liang; Huang, Wen; Yu, Jia; Shao, Weihua; Wang, Xinfa; Liu, Meiling; Zhou, Jingjing; Xie, Peng

    2015-04-15

    Fluoxetine, a selective serotonin reuptake inhibitor (SSRI), is a prescribed and effective antidepressant and generally used for the treatment of depression. Previous studies have revealed that the antidepressant mechanism of fluoxetine was related to astrocytes. However, the therapeutic mechanism underlying its mode of action in astrocytes remains largely unclear. In this study, primary astrocytes were exposed to 10 µM fluoxetine; 24 h post-treatment, a high-resolution proton nuclear magnetic resonance (1H NMR)-based metabolomic approach coupled with multivariate statistical analysis was used to characterize the metabolic variations of intracellular metabolites. The orthogonal partial least-squares discriminant analysis (OPLS-DA) score plots of the spectra demonstrated that the fluoxetine-treated astrocytes were significantly distinguished from the untreated controls. In total, 17 differential metabolites were identified to discriminate the two groups. These key metabolites were mainly involved in lipids, lipid metabolism-related molecules and amino acids. This is the first study to indicate that fluoxetine may exert antidepressant action by regulating the astrocyte's lipid and amino acid metabolism. These findings should aid our understanding of the biological mechanisms underlying fluoxetine therapy.

  16. Quantitative determination of carboxylic acids, amino acids, carbohydrates, ethanol and hydroxymethylfurfural in honey by (1)H NMR.

    PubMed

    del Campo, Gloria; Zuriarrain, Juan; Zuriarrain, Andoni; Berregi, Iñaki

    2016-04-01

    A method using (1)H NMR spectroscopy has been developed to quantify simultaneously thirteen analytes in honeys without previous separation or pre-concentration steps. The method has been successfully applied to determine carboxylic acids (acetic, formic, lactic, malic and succinic acids), amino acids (alanine, phenylalanine, proline and tyrosine), carbohydrates (α- and β-glucose and fructose), ethanol and hydroxymethylfurfural in eucalyptus, heather, lavender, orange blossom, thyme and rosemary honeys. Quantification was performed by using the area of the signal of each analyte in the honey spectra, together with external standards. The regression analysis of the signal area against concentration plots, used for the calibration of each analyte, indicates a good linearity over the concentration ranges found in honeys, with correlation coefficients higher than 0.985 for the thirteen quantified analytes. The recovery studies give values over the 93.7-105.4% range with relative standard deviations lower than 7.4%. Good precision, with relative standard deviations over the range of 0.78-5.21% is obtained.

  17. Ion pairs of indobenzimidazolo cyanines: a structural study based on conductivity, absorption, fluorescence and 1H-NMR

    NASA Astrophysics Data System (ADS)

    Tatikolov, Aleksandr S.; Ishchenko, Aleksandr A.; Ghelli, Stefano; Ponterini, Glauco

    1998-11-01

    Asymmetric benzimidazolo carbo, di- and tricarbocyanines form ion pairs of the solvent-separated and contact types with different counterions in tetrahydrofuran, toluene and toluene-nitrile mixtures. The dissociation constants of the ion pairs in tetrahydrofuran, evaluated from conductivity data, do not depend on the length of the polymethine chain and show only a small decrease with decreasing counterion size. The absorption and fluorescence excitation spectra of the contact ion pairs exhibit a pronounced hypsochromic shift with respect to the solvated ions and the solvent-separated ion pairs. 1H-NMR experiments have provided information about the electronic structures of the ions of both the asymmetric dyes and the corresponding symmetric carbocyanines. They have also revealed different preferred anion locations in the contact ion pairs of the symmetric indocarbocyanine on one hand, and of the benzimidazolo carbocyanine and the asymmetric dyes on the other. This structural difference is suggested to be a cause of the observed opposite effects of ion pairing on the isomerization kinetics of the two groups of dyes.

  18. Metastatic Melanoma Induced Metabolic Changes in C57BL/6J Mouse Stomach Measured by 1H NMR Spectroscopy

    SciTech Connect

    Hu, M; Wang, Xiliang

    2014-12-05

    Melanoma is a malignant tumor of melanocytes with high capability of invasion and rapid metastasis to other organs. Malignant melanoma is the most common metastatic malignancy found in gastrointestinal tract (GI). To the best of our knowledge, previous studies of melanoma in gastrointestinal tract are all clinical case reports. In this work, 1H NMR-based metabolomics approach is used to investigate the metabolite profiles differences of stomach tissue extracts of metastatic B16-F10 melanoma in C57BL/6J mouse and search for specific metabolite biomarker candidates. Principal Component Analysis (PCA), an unsupervised multivariate data analysis method, is used to detect possible outliers, while Orthogonal Projection to Latent Structure (OPLS), a supervised multivariate data analysis method, is employed to evaluate important metabolites responsible for discriminating the control and the melanoma groups. Both PCA and OPLS results reveal that the melanoma group can be well separated from its control group. Among the 50 identified metabolites, it is found that the concentrations of 19 metabolites are statistically and significantly changed with the levels of O-phosphocholine and hypoxanthine down-regulated while the levels of isoleucine, leucine, valine, isobutyrate, threonine, cadaverine, alanine, glutamate, glutamine, methionine, citrate, asparagine, tryptophan, glycine, serine, uracil, and formate up-regulated in the melanoma group. These significantly changed metabolites are associated with multiple biological pathways and may be potential biomarkers for metastatic melanoma in stomach.

  19. Identification and quantification of major steviol glycosides in Stevia rebaudiana purified extracts by 1H NMR spectroscopy.

    PubMed

    Pieri, Valerio; Belancic, Andrea; Morales, Susana; Stuppner, Hermann

    2011-05-11

    The use of (1)H NMR spectroscopy for the characterization of Stevia rebaudiana extracts is presented. The developed method allows qualitative and quantitative determination of the major steviol glycosides in purified extracts and fractions obtained from various stages of the purification process. Moreover, it proved to be a powerful tool to differentiate between glycosides which are naturally occurring in the stevia plant and artifacts formed in the course of the manufacturing process. Identification of steviol glycosides was achieved by the use of 2D NMR techniques, whereas quantification is based on qHNMR using anthracene as internal standard. The solvent mixture pyridine-d(5)-DMSO-d(6) (6:1) enabled satisfactory separation of the signals to be integrated. Validation of the method was performed in terms of specificity, precision, accuracy, linearity, robustness, and stability. Quantitative results were compared to those obtained with the JECFA HPLC-UV method and were found to be in reasonable agreement. NMR analysis does not rely on the use of reference compounds and enables significantly faster analysis compared to HPLC-UV. Thus, NMR represents a feasible alternative to HPLC-based methods for the quality control of Stevia rebaudiana extracts.

  20. (1)H-NMR-based metabolomic analysis of the effect of moderate wine consumption on subjects with cardiovascular risk factors.

    PubMed

    Vázquez-Fresno, Rosa; Llorach, Rafael; Alcaro, Francesca; Rodríguez, Miguel Ángel; Vinaixa, Maria; Chiva-Blanch, Gemma; Estruch, Ramon; Correig, Xavier; Andrés-Lacueva, Cristina

    2012-08-01

    Moderate wine consumption is associated with health-promoting activities. An H-NMR-based metabolomic approach was used to identify urinary metabolomic differences of moderate wine intake in the setting of a prospective, randomized, crossover, and controlled trial. Sixty-one male volunteers with high cardiovascular risk factors followed three dietary interventions (28 days): dealcoholized red wine (RWD) (272mL/day, polyphenol control), alcoholized red wine (RWA) (272mL/day) and gin (GIN) (100mL/day, alcohol control). After each period, 24-h urine samples were collected and analyzed by (1) H-NMR. According to the results of a one-way ANOVA, significant markers were grouped in four categories: alcohol-related markers (ethanol); gin-related markers; wine-related markers; and gut microbiota markers (hippurate and 4-hydroxphenylacetic acid). Wine metabolites were classified into two groups; first, metabolites of food metabolome: tartrate (RWA and RWD), ethanol, and mannitol (RWA); and second, biomarkers that relates to endogenous modifications after wine consumption, comprising branched-chain amino acid (BCAA) metabolite (3-methyl-oxovalerate). Additionally, a possible interaction between alcohol and gut-related biomarkers has been identified. To our knowledge, this is the first time that this approach has been applied in a nutritional intervention with red wine. The results show the capacity of this approach to obtain a comprehensive metabolome picture including food metabolome and endogenous biomarkers of moderate wine intake.

  1. Two-dimensional 1H-NMR study of the spatial structure of neurotoxin II from Naja naja oxiana.

    PubMed

    Golovanov, A P; Lomize, A L; Arseniev, A S; Utkin, Y N; Tsetlin, V I

    1993-05-01

    The spatial structure of neurotoxin II from the venom of the central Asian cobra Naja naja oxiana was determined by two-dimensional 1H-NMR techniques and computational analysis. Nearly complete proton resonance assignments for 61 amino acid residues have been made using two-dimensional (2D) homonuclear total correlated spectroscopy, 2D homonuclear double-quantum-filtered correlated spectroscopy and 2D homonuclear NOE spectroscopy (NOESY) experiments. The cross-peak volumes in NOESY spectra spin-spin coupling constants of vicinal protons NH-C alpha H and C alpha H-C beta H and the observation of slow deuterium exchange of amide protons were used to define local structure and a set of constraints for distance geometry program DIANA. The average root-mean-square deviations are 53 pm for backbone heavy atoms and 118 pm for all heavy atoms of 19 final neurotoxin II conformations. The spatial structure is characterized by a short double-stranded (residues 1-5 and 13-17) and a triple-stranded (residues 22-30, 33-41 and 50-54) antiparallel beta-sheets.

  2. Combined Transcriptomic–1H NMR Metabonomic Study Reveals That Monoethylhexyl Phthalate Stimulates Adipogenesis and Glyceroneogenesis in Human Adipocytes

    PubMed Central

    2011-01-01

    Adipose tissue is a major storage site for lipophilic environmental contaminants. The environmental metabolic disruptor hypothesis postulates that some pollutants can promote obesity or metabolic disorders by activating nuclear receptors involved in the control of energetic homeostasis. In this context, monoethylhexyl phthalate (MEHP) is of particular concern since it was shown to activate the peroxisome proliferator-activated receptor γ (PPARγ) in 3T3-L1 murine preadipocytes. In the present work, we used an untargeted, combined transcriptomic-1H NMR-based metabonomic approach to describe the overall effect of MEHP on primary cultures of human subcutaneous adipocytes differentiated in vitro. MEHP stimulated rapidly and selectively the expression of genes involved in glyceroneogenesis, enhanced the expression of the cytosolic phosphoenolpyruvate carboxykinase, and reduced fatty acid release. These results demonstrate that MEHP increased glyceroneogenesis and fatty acid reesterification in human adipocytes. A longer treatment with MEHP induced the expression of genes involved in triglycerides uptake, synthesis, and storage; decreased intracellular lactate, glutamine, and other amino acids; increased aspartate and NAD, and resulted in a global increase in triglycerides. Altogether, these results indicate that MEHP promoted the differentiation of human preadipocytes to adipocytes. These mechanisms might contribute to the suspected obesogenic effect of MEHP. PMID:22017230

  3. Geometry of the antitumor drug ditercalinium bisintercalated into d(CpGpCpG)2 by 1H NMR.

    PubMed Central

    Delbarre, A; Delepierre, M; Garbay, C; Igolen, J; Le Pecq, J B; Roques, B P

    1987-01-01

    Rigid 7H-pyrido[4,3-c]carbazole dimers, such as Ditercalinium, are DNA bisintercalators that display high DNA affinity and strong antitumor properties. This activity appears crucially dependent on the geometry of their complexes with DNA. Therefore, structures of the complexes formed by the self-complementary tetranucleotide d(CpGpCpG) with Ditercalinium and with a related monomer were investigated in 0.1 M [2H]acetate buffer (pH 5.5) by using 400-MHz 1H NMR. In both cases, d(CpGpCpG) retained a right-handed duplex structure as shown by exchangeable-proton analysis and intramolecular nuclear Overhauser effect measurements. According to the large upfield shifts measured on the base protons (including the imino proton) and on the aromatic protons of the pyridocarbazole rings, the monomer appears to monointercalate and the dimer to bisintercalate into the tetranucleotide duplex. Ditercalinium dissociates from its complex about 100-1000 times slower than does the monomer. The negative intermolecular nuclear Overhauser effects observed on protons corresponding to the convex edge of the pyridocarbazole rings when the sugar protons are saturated suggest that both ligands intercalate with their chain oriented to the wide groove side of the helix, a situation mimicking that encountered with repressors. Antitumor activity of 7H-pyridocarbazole derivatives is discussed in terms of geometry of the intercalated complexes. PMID:3470783

  4. Combining 1H NMR spectroscopy and multivariate regression techniques to quantitatively determine falsification of porcine heparin with bovine species.

    PubMed

    Monakhova, Yulia B; Diehl, Bernd W K

    2015-11-10

    (1)H NMR spectroscopy was used to distinguish pure porcine heparin and porcine heparin blended with bovine species and to quantify the degree of such adulteration. For multivariate modelling several statistical methods such as partial least squares regression (PLS), ridge regression (RR), stepwise regression with variable selection (SR), stepwise principal component regression (SPCR) were utilized for modeling NMR data of in-house prepared blends (n=80). The models were exhaustively validated using independent test and prediction sets. PLS and RR showed the best performance for estimating heparin falsification regarding its animal origin with the limit of detection (LOD) and root mean square error of validation (RMSEV) below 2% w/w and 1% w/w, respectively. Reproducibility expressed in coefficients of variation was estimated to be below 10% starting from approximately 5% w/w of bovine adulteration. Acceptable calibration model was obtained by SPCR, by its application range was limited, whereas SR is least recommended for heparin matrix. The developed method was found to be applicable also to heparinoid matrix (not purified heparin). In this case root mean square of prediction (RMSEP) and LOD were approximately 7% w/w and 8% w/w, respectively. The simple and cheap NMR method is recommended for screening of heparin animal origin in parallel with official NMR test of heparin authenticity and purity.

  5. [superscript 1]H NMR Spectroscopy-Based Configurational Analysis of Mono- and Disaccharides and Detection of ß-Glucosidase Activity: An Undergraduate Biochemistry Laboratory

    ERIC Educational Resources Information Center

    Periyannan, Gopal R.; Lawrence, Barbara A.; Egan, Annie E.

    2015-01-01

    A [superscript 1]H NMR spectroscopy-based laboratory experiment explores mono- and disaccharide structural chemistry, and the enzyme-substrate specificity of glycosidic bond cleavage by ß-glucosidase towards cellobiose (ß-linked gluco-disaccharide) and maltose (a-linked gluco-disaccharide). Structural differences between cellobiose, maltose, and…

  6. Elucidation of the resting state of a rhodium NNN-pincer hydrogenation catalyst that features a remarkably upfield hydride (1)H NMR chemical shift.

    PubMed

    Hänninen, Mikko M; Zamora, Matthew T; MacNeil, Connor S; Knott, Jackson P; Hayes, Paul G

    2016-01-11

    Rhodium(I) alkene complexes of an NNN-pincer ligand catalyze the hydrogenation of alkenes, including ethylene. The terminal or resting state of the catalyst, which exhibits an unprecedentedly upfield Rh-hydride (1)H NMR chemical shift, has been isolated and a synthetic cycle for regenerating the catalytically active species has been established.

  7. 1H NMR characterization of the intermediate formed upon UV-A excitation of biopterin, neopterin and 6-hydroxymethylpterin in O 2-free aqueous solutions

    NASA Astrophysics Data System (ADS)

    Vignoni, Mariana; Salum, M. Laura; Erra-Balsells, Rosa; Thomas, Andres H.; Cabrerizo, Franco M.

    2010-01-01

    Pterins belong to a family of heterocyclic compounds present in a wide range of living systems and participate in relevant biological functions. Under anaerobic conditions, the unstable red intermediate generated by UV-A irradiation of biopterin, neopterin and 6-hydroxymethylpterin was identified by 1H NMR analysis, in alkaline D 2O solutions, as 5,8-dihydro-6-formylpterin.

  8. Chiral discrimination of α-hydroxy acids and N-Ts-α-amino acids induced by tetraaza macrocyclic chiral solvating agents by using (1)H NMR spectroscopy.

    PubMed

    Lv, Caixia; Feng, Lei; Zhao, Hongmei; Wang, Guo; Stavropoulos, Pericles; Ai, Lin

    2017-02-21

    In the field of chiral recognition, reported chiral discrimination by (1)H NMR spectroscopy has mainly focused on various chiral analytes with a single chiral center, regarded as standard chiral substrates to evaluate the chiral discriminating abilities of a chiral auxiliary. Among them, chiral α-hydroxy acids, α-amino acids and their derivatives are chiral organic molecules involved in a wide variety of biological processes, and also play an important role in the area of preparation of pharmaceuticals, as they are part of the synthetic process in the production of chiral drug intermediates and protein-based drugs. In this paper, several α-hydroxy acids and N-Ts-α-amino acids were used to evaluate the chiral discriminating abilities of tetraaza macrocyclic chiral solvating agents (TAMCSAs) 1a-1d by (1)H NMR spectroscopy. The results indicate that α-hydroxy acids and N-Ts-α-amino acids were successfully discriminated in the presence of TAMCSAs 1a-1d by (1)H NMR spectroscopy in most cases. The enantiomers of the α-hydroxy acids and N-Ts-α-amino acids were assigned based on the change of integration of the (1)H NMR signals of the corresponding protons. The enantiomeric excesses (ee) of N-Ts-α-amino acids 11 with different optical compositions were calculated based on the integration of the (1)H NMR signals of the CH3 protons (Ts group) of the enantiomers of (R)- and (S)-11 in the presence of TAMCSA 1b. At the same time, the possible chiral discriminating behaviors have been discussed by means of the Job plots of (±)-2 with TAMCSAs 1b and proposed theoretical models of the enantiomers of 2 and 6 with TAMCSA 1a, respectively.

  9. Simultaneous Analysis of Major Coenzymes of Cellular Redox Reactions and Energy Using ex Vivo (1)H NMR Spectroscopy.

    PubMed

    Nagana Gowda, G A; Abell, Lauren; Lee, Chi Fung; Tian, Rong; Raftery, Daniel

    2016-05-03

    Coenzymes of cellular redox reactions and cellular energy mediate biochemical reactions fundamental to the functioning of all living cells. Despite their immense interest, no simple method exists to gain insights into their cellular concentrations in a single step. We show that a simple (1)H NMR experiment can simultaneously measure oxidized and reduced forms of nicotinamide adenine dinucleotide (NAD(+) and NADH), oxidized and reduced forms of nicotinamide adenine dinucleotide phosphate (NADP(+) and NADPH), and adenosine triphosphate (ATP) and its precursors, adenosine diphosphate (ADP) and adenosine monophosphate (AMP), using mouse heart, kidney, brain, liver, and skeletal muscle tissue extracts as examples. Combining 1D/2D NMR experiments, chemical shift libraries, and authentic compound data, reliable peak identities for these coenzymes have been established. To assess this methodology, cardiac NADH and NAD(+) ratios/pool sizes were measured using mouse models with a cardiac-specific knockout of the mitochondrial Complex I Ndufs4 gene (cKO) and cardiac-specific overexpression of nicotinamide phosphoribosyltransferase (cNAMPT) as examples. Sensitivity of NAD(+) and NADH to cKO or cNAMPT was observed, as anticipated. Time-dependent investigations showed that the levels of NADH and NADPH diminish by up to ∼50% within 24 h; concomitantly, NAD(+) and NADP(+) increase proportionately; however, degassing the sample and flushing the sample tubes with helium gas halted such changes. The analysis protocol along with the annotated characteristic fingerprints for each coenzyme is provided for easy identification and absolute quantification using a single internal reference for routine use. The ability to visualize the ubiquitous coenzymes fundamental to cellular functions, simultaneously and reliably, offers a new avenue to interrogate the mechanistic details of cellular function in health and disease.

  10. Whole Blood Metabolomics by (1)H NMR Spectroscopy Provides a New Opportunity To Evaluate Coenzymes and Antioxidants.

    PubMed

    Nagana Gowda, G A; Raftery, Daniel

    2017-03-30

    Conventional human blood metabolomics employs serum or plasma and provides a wealth of metabolic information therein. However, this approach lacks the ability to measure and evaluate important metabolites such as coenzymes and antioxidants that are present at high concentrations in red blood cells. As an important alternative to serum/plasma metabolomics, we show here that a simple (1)H NMR experiment can simultaneously measure coenzymes and antioxidants in extracts of whole human blood, in addition to the nearly 70 metabolites that were shown to be quantitated in serum/plasma recently [ Anal. Chem. 2015 , 87 , 706 - 715 ]. Coenzymes of redox reactions: oxidized/reduced nicotinamide adenine dinucleotide (NAD(+) and NADH) and nicotinamide adenine dinucleotide phosphate (NADP(+) and NADPH); coenzymes of energy including adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP); and antioxidants, the sum of oxidized and reduced glutathione (GSSG and GSH) can be measured with essentially no additional effort. A new method was developed for detecting many of these unstable species without affecting other blood/blood plasma metabolites. The identities of coenzymes and antioxidants in blood NMR spectra were established combining 1D/2D NMR techniques, chemical shift databases, pH measurements and, finally, spiking with authentic compounds. This is the first study to report identification of major coenzymes and antioxidants and quantify them, simultaneously, with the large pool of other metabolites in human blood using NMR spectroscopy. Considering that the levels of coenzymes and antioxidants represent a sensitive measure of cellular functions in health and numerous diseases, the NMR method presented here potentially opens a new chapter in the metabolomics of blood.

  11. Conformational studies on 2-substituted ethanesulfonates in aqueous solution by 1H NMR spectroscopy and DFT calculations

    NASA Astrophysics Data System (ADS)

    Musio, Roberta; Sciacovelli, Oronzo

    2009-09-01

    The conformation of some 2-substituted sodium ethanesulfonates exerting biological functions, XCH 2CH 2SO 3Na (X = S -, Br, Cl, OH, NH 2, SH), has been investigated in aqueous solution by 1H NMR spectroscopy. Potential energy curves for rotation about the C-C bond have been calculated at DFT level of theory (B3LYP/6-311++G(2d,p)) in vacuum and in water (by IEF-PCM method). As concerning dianionic coenzyme M (X = S -), 2-bromo- and 2-chloroethanesulfonate, in vacuum the torsional potential curves and the variations of atomic charges and geometric parameters suggest that electrostatic and steric repulsions between the substituent X and -SO3- moiety determine the preference for anti conformer. In isethionate (X = OH), anionic taurine (X = NH 2), and coenzyme M (X = SH), the formation of an intramolecular hydrogen bond stabilizes also gauche-like conformers and the torsional potential curves exhibit two minima. According to Natural Bond Orbital analysis, hydrogen bond can be ascribed to electron transfer from two oxygen lone-pairs of the -SO3- moiety to the antibonding Y-H orbital of the substituent X. In all the compounds examined, hyperconjugative interactions tend to stabilize the gauche conformers with respect to the anti one. This means that conformational preferences in vacuum are determined by a counterbalancing of electrostatic, steric, and hyperconjugative interactions. Calculations in vacuum are not in agreement with the experimental conformational behaviour of the compounds examined. In order to reproduce the experimental results at least qualitatively, solvent effect must be introduced.

  12. Simultaneous Analysis of Major Coenzymes of Cellular Redox Reactions and Energy Using ex Vivo 1H NMR Spectroscopy

    PubMed Central

    2016-01-01

    Coenzymes of cellular redox reactions and cellular energy mediate biochemical reactions fundamental to the functioning of all living cells. Despite their immense interest, no simple method exists to gain insights into their cellular concentrations in a single step. We show that a simple 1H NMR experiment can simultaneously measure oxidized and reduced forms of nicotinamide adenine dinucleotide (NAD+ and NADH), oxidized and reduced forms of nicotinamide adenine dinucleotide phosphate (NADP+ and NADPH), and adenosine triphosphate (ATP) and its precursors, adenosine diphosphate (ADP) and adenosine monophosphate (AMP), using mouse heart, kidney, brain, liver, and skeletal muscle tissue extracts as examples. Combining 1D/2D NMR experiments, chemical shift libraries, and authentic compound data, reliable peak identities for these coenzymes have been established. To assess this methodology, cardiac NADH and NAD+ ratios/pool sizes were measured using mouse models with a cardiac-specific knockout of the mitochondrial Complex I Ndufs4 gene (cKO) and cardiac-specific overexpression of nicotinamide phosphoribosyltransferase (cNAMPT) as examples. Sensitivity of NAD+ and NADH to cKO or cNAMPT was observed, as anticipated. Time-dependent investigations showed that the levels of NADH and NADPH diminish by up to ∼50% within 24 h; concomitantly, NAD+ and NADP+ increase proportionately; however, degassing the sample and flushing the sample tubes with helium gas halted such changes. The analysis protocol along with the annotated characteristic fingerprints for each coenzyme is provided for easy identification and absolute quantification using a single internal reference for routine use. The ability to visualize the ubiquitous coenzymes fundamental to cellular functions, simultaneously and reliably, offers a new avenue to interrogate the mechanistic details of cellular function in health and disease. PMID:27043450

  13. (1)H NMR-based metabolomics reveals neurochemical alterations in the brain of adolescent rats following acute methylphenidate administration.

    PubMed

    Quansah, Emmanuel; Ruiz-Rodado, Victor; Grootveld, Martin; Probert, Fay; Zetterström, Tyra S C

    2017-03-06

    The psychostimulant methylphenidate (MPH) is increasingly used in the treatment of attention deficit hyperactivity disorder (ADHD). While there is little evidence for common brain pathology in ADHD, some studies suggest a right hemisphere dysfunction among people diagnosed with the condition. However, in spite of the high usage of MPH in children and adolescents, its mechanism of action is poorly understood. Given that MPH blocks the neuronal transporters for dopamine and noradrenaline, most research into the effects of MPH on the brain has largely focused on these two monoamine neurotransmitter systems. Interestingly, recent studies have demonstrated metabolic changes in the brain of ADHD patients, but the impact of MPH on endogenous brain metabolites remains unclear. In this study, a proton nuclear magnetic resonance ((1)H NMR)-based metabolomics approach was employed to investigate the effects of MPH on brain biomolecules. Adolescent male Sprague Dawley rats were injected intraperitoneally with MPH (5.0 mg/kg) or saline (1.0 ml/kg), and cerebral extracts from the left and right hemispheres were analysed. A total of 22 variables (representing 13 distinct metabolites) were significantly increased in the MPH-treated samples relative to the saline-treated controls. The upregulated metabolites included: amino acid neurotransmitters such as GABA, glutamate and aspartate; large neutral amino acids (LNAA), including the aromatic amino acids (AAA) tyrosine and phenylalanine, both of which are involved in the metabolism of dopamine and noradrenaline; and metabolites associated with energy and cell membrane dynamics, such as creatine and myo-inositol. No significant differences in metabolite concentrations were found between the left and right cerebral hemispheres. These findings provide new insights into the mechanisms of action of the anti-ADHD drug MPH.

  14. 1H-NMR comparative study of the active site in shark (Galeorhinus japonicus), horse, and sperm whale deoxy myoglobins.

    PubMed

    Yamamoto, Y; Iwafune, K; Chûjô, R; Inoue, Y; Imai, K; Suzuki, T

    1992-09-01

    1H-NMR spectra of deoxy myoglobins (Mbs) from shark (Galeorhinus japonicus), horse, and sperm whale have been studied to gain insights into their active site structure. It has been demonstrated for the first time that nuclear Overhauser effect (NOE) can be observed between heme peripheral side-chain proton resonances of these paramagnetic complexes. Val-E11 methyl and His-F8 C delta H proton resonances of these Mbs were also assigned from the characteristic shift and line width. The hyperfine shift of the former resonance was used to calculate the magnetic anisotropy of the protein. The shift analysis of the latter resonance, together with the previously assigned His-F8 N delta H proton resonance, revealed that the strain on the Fe-N epsilon bond is in the order horse Mb approximately whale Mb < shark Mb and that the hydrogen bond strength of the His-F8 N delta H proton to the main-chain carbonyl oxygen in the preceding turn of the F helix is in the order shark Mb < horse Mb < whale Mb. Weaker Feporphyrin interaction in shark Mb was manifested in a smaller shift of the heme methyl proton resonance and appears to result from distortion of the coordination geometry in this Mb. Larger strain on the Fe-N epsilon bond in shark Mb should be to some extent attributed to its lowered O2 affinity (P50 = 1.1 mmHg at 20 degrees C), compared to whale and horse Mbs.

  15. Method development and validation: quantitation of telmisartan bulk drug and its tablet formulation by (1) H NMR spectroscopy.

    PubMed

    Jadeja, Yashwantsinh; Chomal, Bhagyawanti; Patel, Madhavi; Jebaliya, Hetal; Khunt, Ranjan; Shah, Anamik

    2016-12-14

    The quantitative NMR (qNMR) spectroscopy is nowadays a new tool for the determination of pharmaceutical potent biologically active molecules in bulk drug and its tablet formulation than the other analytical techniques. Herein, qNMR method was developed for an anti-hypertensive drug, telmisartan in bulk drug and its tablet formulation. The precise method was developed by using malononitrile as an internal standard. The methylene signal of telmisartan appeared at δ = 5.46 ppm (singlet) relative to the signal of malononitrile at δ = 3.59 ppm (singlet) in CDCl3 , as an NMR solvent. The development and validation of the method were carried out as per International Conference on Harmonization guidelines. The method was found to be linear (r(2)  = 0.9999) for 0.5 to 3.5 mg/ml in the drug concentration range. The relative standard deviation for accuracy and precession was not more than 2.0%. The sensitivity of the method was carried out by limit of detection and a limit of quantification, at 0.05 and 0.2 mg/ml, respectively, concentration. The robustness of the method was studied by changing parameters as well as different solvent manufacturer company. The result shows that method was accurately developed for quantification of telmisartan in pharmaceutical dosage form. The developed method by (1) H NMR spectroscopy is comparatively easy and more precise with respect to the other analytical tools. Copyright © 2016 John Wiley & Sons, Ltd.

  16. 1H NMR-based serum metabolomics reveals erythromycin-induced liver toxicity in albino Wistar rats

    PubMed Central

    Rawat, Atul; Dubey, Durgesh; Guleria, Anupam; Kumar, Umesh; Keshari, Amit K.; Chaturvedi, Swati; Prakash, Anand; Saha, Sudipta; Kumar, Dinesh

    2016-01-01

    Introduction: Erythromycin (ERY) is known to induce hepatic toxicity which mimics other liver diseases. Thus, ERY is often used to produce experimental models of drug-induced liver-toxicity. The serum metabolic profiles can be used to evaluate the liver-toxicity and to further improve the understanding of underlying mechanism. Objective: To establish the serum metabolic patterns of Erythromycin induced hepatotoxicity in albino wistar rats using 1H NMR based serum metabolomics. Experimental: Fourteen male rats were randomly divided into two groups (n = 7 in each group): control and ERY treated. After 28 days of intervention, the metabolic profiles of sera obtained from ERY and control groups were analyzed using high-resolution 1D 1H CPMG and diffusion-edited nuclear magnetic resonance (NMR) spectra. The histopathological and SEM examinations were employed to evaluate the liver toxicity in ERY treated group. Results: The serum metabolic profiles of control and ERY treated rats were compared using multivariate statistical analysis and the metabolic patterns specific to ERY-induced liver toxicity were established. The toxic response of ERY was characterized with: (a) increased serum levels of Glucose, glutamine, dimethylamine, malonate, choline, phosphocholine and phospholipids and (b) decreased levels of isoleucine, leucine, valine, alanine, glutamate, citrate, glycerol, lactate, threonine, circulating lipoproteins, N-acetyl glycoproteins, and poly-unsaturated lipids. These metabolic alterations were found to be associated with (a) decreased TCA cycle activity and enhanced fatty acid oxidation, (b) dysfunction of lipid and amino acid metabolism and (c) oxidative stress. Conclusion and Recommendations: Erythromycin is often used to produce experimental models of liver toxicity; therefore, the established NMR-based metabolic patterns will form the basis for future studies aiming to evaluate the efficacy of anti-hepatotoxic agents or the hepatotoxicity of new drug

  17. Haemolymph from Mytilus galloprovincialis: Response to copper and temperature challenges studied by (1)H-NMR metabonomics.

    PubMed

    Digilio, Giuseppe; Sforzini, Susanna; Cassino, Claudio; Robotti, Elisa; Oliveri, Caterina; Marengo, Emilio; Musso, Davide; Osella, Domenico; Viarengo, Aldo

    2016-01-01

    Numerous studies on molluscs have been carried out to clarify the physiological roles of haemolymph serum proteins and haemocytes. However, little is known about the presence and functional role of the serum metabolites. In this study, Nuclear Magnetic Resonance (NMR) was used to assess whether changes of the metabolic profile of Mytilus galloprovincialis haemolymph may reflect alterations of the physiological status of the organisms due to environmental stressors, namely copper and temperature. Mussel haemolymph was taken from the posterior adductor muscle after a 4-day exposure to ambient (16 °C) or high temperature (24 °C) and in the absence or presence (5 μg/L, 20 μg/L, or 40 μg/L) of sublethal copper (Cu(2+)). The total glutathione (GSH) concentration in the haemolymph of both control and treated mussels was minimal, indicating the absence of significant contaminations by muscle intracellular metabolites due to the sampling procedure. In the (1)H-NMR spectrum of haemolymph, 27 metabolites were identified unambiguously. The separate and combined effects of exposure to copper and temperature on the haemolymph metabolic profile were assessed by Principal Component Analysis (PCA) and Ranking-PCA multivariate analysis. Changes of the metabolomic profile due to copper exposure at 16 °C became detectable at a dose of 20 μg/L copper. Alanine, lysine, serine, glutamine, glycogen, glucose and protein aliphatics played a major role in the classification of the metabolic changes according to the level of copper exposition. High temperature (24 °C) and high copper levels caused a coherent increase of a common set of metabolites (mostly glucose, serine, and lysine), indicating that the metabolic impairment due to high temperature is enforced by the presence of copper. Overall, the results demonstrate that, as for human blood plasma, the analysis of haemolymph metabolites represents a promising tool for the diagnosis of pollutant-induced stress syndrome in marine

  18. 1H and 13C NMR assignments for new heterocyclic TAM leuco dyes, (2Z,2'E)-2,2'-(2-phenyl propane-1,3-diylidene) bis(1,3,3-trimethylindoline) derivatives. Part II.

    PubMed

    Keum, Sam-Rok; Roh, Se-Jung; Lee, Min-Hyung; Sauriol, Francoise; Buncel, Erwin

    2008-09-01

    The (1)H and (13)C NMR spectra of the novel heterocyclic Leuco-TAM dyes, (2Z, 2'E)-2,2'-(2-phenyl propane-1,3-diylidene) bis(1,3,3-trimethylindoline) derivatives 1-4 as precursors of triarylmethane (TAM)(+) (Malachite Green FB-analog) dyes were completely assigned by 1D and 2D NMR experiments, including DEPT, COSY, HSQC, HMBC, and NOESY. Especially, the diastereotopic gem-dimethyl protons at the C3 and C3' positions of the FB rings were definitively assigned. The (Z,E) isomers adopt the energetically favored three-bladed propeller conformation in solution.

  19. Structural study of (±) ethyl 3-acyloxy-1-azabicyclo[2.2.2]octane-3-carboxylates by 1H, 13C NMR spectroscopy, X-ray crystallography and DFT calculations

    NASA Astrophysics Data System (ADS)

    Arias-Pérez, M. S.; Cosme, A.; Gálvez, E.; Morreale, A.; Sanz-Aparicio, J.; Fonseca, I.

    2006-05-01

    1H, 13C NMR spectroscopy and DFT/B3LYP calculations were applied to investigate the conformational preferences of the ethoxycarbonyl and acyloxy groups of some α-acyloxyesters derived from (±) ethyl 3-hydroxy-1-azabicyclo[2.2.2]octane-3-carboxylate. The crystal structure of (±) ethyl 3-diphenylacetoxy-1-azabicyclo[2.2.2]octane-3-carboxylate was determined by X-ray diffraction. To correlate between calculated conformations and the structure in solution, NMR chemical shifts calculations were also performed using the GIAO approach. It has been found that the lowest energetic conformer computed gives the greatest correspondance with experimental solution and solid state data.

  20. 1H and 13C NMR Assignments of Cytotoxic 3S-1,2,3,4-Tetrahydro-β-carboline-3-carboxylic Acid from the Leaves of Cichorium endivia

    PubMed Central

    Wang, Fu-Xin; Deng, An-Jun; Wei, Jin-Feng; Qin, Hai-Lin; Wang, Ai-Ping

    2012-01-01

    An amino acid, 3S-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid, was isolated for the first time from the leaves of Cichorium endivia. The complete assignment of its 1H and 13C NMR spectroscopic data was carried out also for the first time based on extensive 1D and 2D NMR experiments. Cytotoxicity of this isolated compound against HCT-8 and HepG2 human cancer cell lines was evaluated for the first time, with moderate activities being found. PMID:23304641

  1. Configuration at C-25 in 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25,26-pentol excreted by patients with cerebrotendinous xanthomatosis: circular dichroism and 13C-NMR studies.

    PubMed

    Dayal, B; Salen, G; Toome, V; Tint, G S

    1986-12-01

    The configuration at C-25 in 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha,25,26-pentol isolated from the bile and feces of patients with cerebrotendinous xanthomtosis (CTX) was determined from the lanthanide-induced circular dichroism (CD) Cotton effects and 13C-NMR measurements. Under anhydrous conditions, CD spectra of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha,25,26-pentol in the presence of Eu(fod)3 exhibited a large induced negative Cotton effect at 320 nm. On the basis of the empirical rule (primary-tertiary-alpha-diols) in which R compounds have positive Cotton effects and S compounds have negative Cotton effects at 320 nm, it was concluded that 25,26-pentol has the 1,2,glycol structure with C-25 having the S-configuration. This assignment was based upon comparison with model compounds, 25(R and S),26-dihydroxy cholesterols and 25(R and S),26-dihydroxy cholecalciferols whose single-crystal X-ray structure and 13C-NMR studies have been performed. It is suggested that these data may be helpful to clarify the stereospecificity of the hydroxylation of the terminal methyl group of the cholesterol side chain in CTX.

  2. Xanthan Gum Removal for 1H-NMR Analysis of the Intracellular Metabolome of the Bacteria Xanthomonas axonopodis pv. citri 306.

    PubMed

    Pegos, Vanessa R; Canevarolo, Rafael R; Sampaio, Aline P; Balan, Andrea; Zeri, Ana C M

    2014-04-22

    Xanthomonas is a genus of phytopathogenic bacteria, which produces a slimy, polysaccharide matrix known as xanthan gum, which involves, protects and helps the bacteria during host colonization. Although broadly used as a stabilizer and thickener in the cosmetic and food industries, xanthan gum can be a troubling artifact in molecular investigations due to its rheological properties. In particular, a cross-reaction between reference compounds and the xanthan gum could compromise metabolic quantification by NMR spectroscopy. Aiming at an efficient gum extraction protocol, for a 1H-NMR-based metabolic profiling study of Xanthomonas, we tested four different interventions on the broadly used methanol-chloroform extraction protocol for the intracellular metabolic contents observation. Lower limits for bacterial pellet volumes for extraction were also probed, and a strategy is illustrated with an initial analysis of X. citri's metabolism by 1H-NMR spectroscopy.

  3. 13C-CPMAS and 1H-NMR study of the inclusion complexes of beta-cyclodextrin with carvacrol, thymol, and eugenol prepared in supercritical carbon dioxide.

    PubMed

    Locci, Emanuela; Lai, Simona; Piras, Alessandra; Marongiu, Bruno; Lai, Adolfo

    2004-09-01

    Beta-cyclodextrin (beta-CD) inclusion complexes with carvacrol (1), thymol (2), and eugenol (3) (components of essential oils of vegetable origin) were prepared by the supercritical CO2 technique, and their structural characterization was achieved by means of 1H-NMR in aqueous solution and 13C-CPMAS NMR in the solid state. Evidence of the formation of the inclusion complexes for all the examined systems was obtained by 1H-NMR in solution, while 2D-ROESY-NMR experiments were used to investigate the geometry of inclusion. In addition, the dynamics of these inclusion complexes in the kHz timescale was investigated by analysis of the 1H and 13C spin-lattice relaxation times in the rotating frame.

  4. Classification of fermented soymilk during fermentation by 1H NMR coupled with principal component analysis and elucidation of free-radical scavenging activities.

    PubMed

    Yang, Seung-Ok; Kim, So-Hyun; Cho, Sayeon; Lee, JaeHwan; Kim, Young-Suk; Yun, Sung-Seob; Choi, Hyung-Kyoon

    2009-05-01

    Changes in metabolites in fermented soymilk prepared with selected Bifidobacterium and Streptococci strains were analyzed using a (1)H-NMR-based metabolomic technique. Principal components analysis (PCA) allowed the clear separation of 50% methanol extracts from fermented soymilk with different fermentation times by combining principal components PC1 and PC3, which accounted for 55.1% of the total variance. Loading plot analysis was performed to select major compounds contributing to the separation, and the relative levels of selected metabolites were determined. In addition, the free-radical scavenging activities of each sample were investigated, and the underlying mechanisms were elucidated by determining the total phenolics and total flavonoids contents of each sample. The present study suggests the usefulness of combining (1)H-NMR with PCA in discriminating fermented soymilk samples with different fermentation times, and elucidates of the factors affecting free-radical scavenging activities of fermented soymilk.

  5. (1)H NMR foodomics reveals that the biodynamic and the organic cultivation managements produce different grape berries (Vitis vinifera L. cv. Sangiovese).

    PubMed

    Picone, Gianfranco; Trimigno, Alessia; Tessarin, Paola; Donnini, Silvia; Rombolà, Adamo Domenico; Capozzi, Francesco

    2016-12-15

    The increasing demand for natural foods and beverages, i.e. prepared by excluding synthetic chemicals along the whole production chain, has boosted the adoption of organic and biodynamic cultivation methods which are based on protocols avoiding use of synthetic pesticides. This trend is striking in viticulture, since wine production is largely shaped by the varying drinking attitudes of environment-friendly consumers. Using (1)H NMR, the compositions of grape berries, collected at harvest in 2009 and 2011, in experimental plots cultivated either with biodynamic or organic methods, were compared. Although the analysis provides a comprehensive metabolic profile of berries, the resulting distinctive pattern consists of a few molecules. Lower content of sugars, coumaric and caffeic acids, as well as higher amount of γ-aminobutyric acid (GABA) were observed in biodynamic grapes. The (1)H NMR foodomics approach evidenced a diverse fruit metabolome that could be associated to a different physiological response of plants to the agronomic environment.

  6. Selective Detection of 1H NMR Resonances of 13CH n Groups Using Two-Dimensional Maximum-Quantum Correlation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Liu, M.; Farrant, R. D.; Nicholson, J. K.; Lindon, J. C.

    Methods for editing spectra based upon maximum-quantum filtering in two-dimensional 1H NMR are presented (MAXY NMR). Separation of 1H resonances from 13CH, 13CH 2, and 13CH 3 groups is demonstrated, using the coherence of the attached natural-abundance 13C spin. Two-dimensional correlation pulse sequences based on J connectivity (MAXY-COSY), total J connectivity (MAXY-TOCSY), and NOE and exchange processes (MAXY-NOESY) are given and exemplified using dexamethasone as a model compound. In addition, an improved form of a 13CH 2 only COSY spectrum (gem-COSY) is shown, and the application of z magnetic-field gradients is demonstrated as an alternative to phase cycling. The approach should have utility in the assignment of complex 1H NMR spectra which arise from peptides or complex mixtures such as biofluids.

  7. Metabolomic quality control of commercial Asian ginseng, and cultivated and wild American ginseng using (1)H NMR and multi-step PCA.

    PubMed

    Zhao, Huiying; Xu, Jin; Ghebrezadik, Helen; Hylands, Peter J

    2015-10-10

    Ginseng, mainly Asian ginseng and American ginseng, is the most widely consumed herbal product in the world . However, the existing quality control method is not adequate: adulteration is often seen in the market. In this study, 31 batches of ginseng from Chinese stores were analyzed using (1)H NMR metabolite profiles together with multi-step principal component analysis. The most abundant metabolites, sugars, were excluded from the NMR spectra after the first principal component analysis, in order to reveal differences contributed by less abundant metabolites. For the first time, robust, distinctive and representative differences of Asian ginseng from American ginseng were found and the key metabolites responsible were identified as sucrose, glucose, arginine, choline, and 2-oxoglutarate and malate. Differences between wild and cultivated ginseng were identified as ginsenosides. A substitute cultivated American ginseng was noticed. These results demonstrated that the combination of (1)H NMR and PCA is effective in quality control of ginseng.

  8. Discrimination of Enantiomers of Dipeptide Derivatives with Two Chiral Centers by Tetraaza Macrocyclic Chiral Solvating Agents Using (1)H NMR Spectroscopy.

    PubMed

    Fang, Lixia; Lv, Caixia; Wang, Guo; Feng, Lei; Stavropoulos, Pericles; Gao, Guangpeng; Ai, Lin; Zhang, Jiaxin

    2016-12-01

    (1)H NMR spectroscopy is often used to discriminate enantiomers of chiral analytes and determine their enantiomeric excess (ee) by various chiral auxiliaries. In reported research, these studies were mainly focused on chiral discriminantion of chiral analytes with only one chiral center. However, many chiral compounds possessing two or more chiral centers are often found in natural products, chiral drugs, products of asymmetric synthesis and biological systems. Therefore, it is necessary to investigate their chiral discrimination by effective chiral auxiliaries using (1)H NMR spectroscopy. In this paper, a new class of tetraaza macrocyclic chiral solvating agents (TAMCSAs) with two amide (CONH), two amino (NH) and two phenolic hydroxyl (PhOH) groups has been designed and synthsized for chiral discrimination towards dipeptide derivatives with two chiral centers. These dipeptide derivatives are important chiral species because some of them are used as clinical drugs and special dietary supplements for treatment of human diseases, such as L-alanyl-L-glutamine and aspartame. The results show that these TAMCSAs have excellent chiral discriminating properties and offer multiple detection possibilities pertaining to (1)H NMR signals of diagnostic split protons. The nonequivalent chemical shifts (up to 0.486 ppm) of various types of protons of these dipeptide derivatives were evaluated with the assistance of well-resolved (1)H NMR signals in most cases. In addition, enantiomeric excesses (ee) of the dipeptide derivatives with different optical compositions have been calculated based on integration of well-separeted proton signals. At the same time, the possible chiral discriminating behaviors have been discussed by means of Job plots, ESI mass spectra and a proposed theoretical model of (±)-G1 with TAMCSA 1c. Additionally, the association constants of enantiomers of (±)-G5 with TAMCSA 1a were calculated by employing the nonlinear curve-fitting method.

  9. 1H-NMR study of diamagnetic cytochrome P450cam: assignment of heme resonances and substrate dependance of one cysteinate beta proton.

    PubMed

    Mouro, C; Bondon, A; Simonneaux, G; Jung, C

    1997-09-08

    The 1H-NMR study of diamagnetic cytochrome P450cam FeII-CO has been performed for the first time. Chemical shifts of the cysteinate fifth ligand protons and of several heme protons have been assigned through 1- and 2-dimensional spectra at 500 MHz. A substrate dependance has been observed for the resonance of the cysteinate proton detected in the high-field region.

  10. Determination of the optical purity of (R)-terbutaline by 1H-NMR and RP-LC using chiral derivatizing agent, (S)-(-)-alpha-methylbenzyl isocyanate.

    PubMed

    Kim, K H; Kim, H J; Kim, J H; Lee, J H; Lee, S C

    2001-07-01

    A simple, convenient and precise 1H-NMR and indirect HPLC methods were used for the determination of (S)-terbutaline in (R)-terbutaline. The enantiomers were converted to diastereomeric derivatives using (S)-(-)-alpha-methylbenzyl isocyanate and were successfully separated on an ODS column within 40 min with RS=1.41 and alpha=1.09. Interaction between chiral solutes by the formation of the diastereomeric complexes also led to differentiations of the 1H-NMR spectra of enantiomers and optical purities were determined on the basis of the peak area of the enantiomeric amine proton resonance. The effect of various experimental parameter, such as reaction time, reaction temperature and concentration of chiral derivatizing agent on the derivatization reaction and composition of mobile phase on the ODS column is discussed. Validation data such as recovery, linearity and detection limit are also presented. The results from 1H-NMR and RP-HPLC methods were compared with those from chiral HPLC method and no racemization was found during the experiments. NMR results had agreed with those obtained by indirect HPLC method and two methods could be used as a quality control method for the enantiomeric purity determination of (R)-terbutaline.

  11. Evidence for altered metabolic pathways during environmental stress: (1)H-NMR spectroscopy based metabolomics and clinical studies on subjects of sea-voyage and Antarctic-stay.

    PubMed

    Yadav, Anand Prakash; Chaturvedi, Shubhra; Mishra, Kamla Prasad; Pal, Sunil; Ganju, Lilly; Singh, Shashi Bala

    2014-08-01

    The Antarctic context is an analogue of space travel, with close similarity in ambience of extreme climate, isolation, constrained living spaces, disrupted sleep cycles, and environmental stress. The present study examined the impact of the harsh habitat of Antarctica on human physiology and its metabolic pathways, by analyzing human serum samples, using (1)H-NMR spectroscopy for identification of metabolites; and quantifying other physiological and clinical parameters for correlation between expression data and metabolite data. Sera from seven adult males (of median age 36years) who participated in this study, from the 28th Indian Expeditionary group to the Antarctica station Maitri, were collected in chronological sequence. These included: i) baseline control; ii) during ship journey; iii) at Antarctica, in the months of March, May, August and November; to enable study of temporal evolution of monitored physiological states. 29 metabolites in serum were identified from the 400MHz (1)H-NMR spectra. Out of these, 19 metabolites showed significant variations in levels, during the ship journey and the stay at Maitri, compared to the base-line levels. Further biochemical analysis also supported these results, indicating that the ship journey, and the long-term Antarctic exposure, affected kidney and liver functioning. Our metabolite data highlights for the first time the effect of environmental stress on the patho-physiology of the human system. Multivariate analysis tools were employed for this metabonomics study, using (1)H-NMR spectroscopy.

  12. UV-visible-DAD and 1H-NMR spectroscopy data fusion for studying the photodegradation process of azo-dyes using MCR-ALS.

    PubMed

    Fernández, Cristina; Pilar Callao, M; Larrechi, M Soledad

    2013-12-15

    The photodegradation process of three azo-dyes - Acid Orange 61, Acid Red 97 and Acid Brown 425 - was monitored simultaneously by ultraviolet-visible spectroscopy with diode array detector (UV-vis-DAD) and (1)H-nuclear magnetic resonance ((1)H-NMR). Multivariate curve resolution-alternating least squares (MCR-ALS) was applied to obtain the concentration and spectral profile of the chemical compounds involved in the process. The analysis of the H-NMR data suggests there are more intermediate compounds than those obtained with the UV-vis-DAD data. The fusion of UV-vis-DAD and the (1)H-NMR signal before the multivariate analysis provides better results than when only one of the two detector signals was used. It was concluded that three degradation products were present in the medium when the three azo-dyes had practically degraded. This study is the first application of UV-vis-DAD and (1)H-NMR spectroscopy data fusion in this field and illustrates its potential as a quick method for evaluating the evolution of the azo-dye photodegradation process.

  13. Monomeric and dimeric structures analysis and spectroscopic characterization of 3,5-difluorophenylboronic acid with experimental (FT-IR, FT-Raman, 1H and 13C NMR, UV) techniques and quantum chemical calculations

    NASA Astrophysics Data System (ADS)

    Karabacak, Mehmet; Kose, Etem; Atac, Ahmet; Asiri, Abdullah M.; Kurt, Mustafa

    2014-01-01

    The spectroscopic properties of 3,5-difluorophenylboronic acid (3,5-DFPBA, C6H3F2B(OH)2) were investigated by FT-IR, FT-Raman UV-Vis, 1H and 13C NMR spectroscopic techniques. FT-IR (4000-400 cm-1) and FT-Raman spectra (3500-10 cm-1) in the solid phase and 1H and 13C NMR spectra in DMSO solution were recorded. The UV spectra that dissolved in ethanol and water were recorded in the range of 200-400 nm for each solution. The structural and spectroscopic data of the molecule have been obtained for possible three conformers from DFT (B3LYP) with 6-311++G(d,p) basis set calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. Hydrogen-bonded dimer of title molecule, optimized by counterpoise correction, was also studied B3LYP at the 6-311++G(d,p) level and the effects of molecular association through O-H⋯O hydrogen bonding have been discussed. 1H and 13C NMR chemical shifts were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, oscillator strength, wavelengths, HOMO and LUMO energies, were performed by time-dependent density functional theory (TD-DFT) results complements with the experimental findings. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (OPDOS) diagrams analysis were presented. The effects due to the substitutions of boric acid group and halogen were investigated. The results of the calculations were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), nonlinear optical properties (NLO) and thermodynamic features were performed.

  14. Partitioning of main and side-chain units between different phases: a solid-state 13C NMR inversion-recovery cross-polarization study on a homogeneous, metallocene-based, ethylene-1-octene copolymer.

    PubMed

    Litvinov, Victor M; Mathot, Vincent B F

    2002-01-01

    13C NMR inversion-recovery cross-polarization experiments are used to study the phase structure and partitioning of main and side-chain groups in a homogeneous, metallocene-based, ethylene-1-octene copolymer. The results provide strong evidence for a three-phase model, i.e. a rigid, (imperfect) crystalline phase, which is mainly composed of long sequences of methylene carbon atoms of the main chain, a semi-rigid, amorphous interphase (also denoted as 'rigid amorphous'), which is enriched by chain segments bearing methylene and methine carbon atoms of the main chain, and a soft fraction of the amorphous phase (also denoted as 'mobile amorphous'), which is largely composed of side chains and short methylene sequences of the main chain.

  15. Static and dynamic interaction between π and d electrons in organic superconductor β″-(BEDT-TTF)4[(H3O ) Fe (C2O4)3] .C6H5Br studied by 13C NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Ihara, Y.; Futami, Y.; Kawamoto, A.; Matsui, K.; Goto, T.; Sasaki, T.; Benmansour, S.; Gómez-García, C. J.

    2016-08-01

    We present the results of 13C NMR experiments in an organic superconductor with localized Fe spins β″-(BEDT-TTF) 4[(H3O ) Fe (C2O4)3] .C6H5Br . We reveal the antiferromagnetic coupling between Fe d spins and π spins, which creates an exchange field antiparallel to the external field direction at the π electrons. In addition to the static effects of Fe spins, we show from the nuclear spin-lattice relaxation rate measurement that the magnetic fluctuations generated by Fe spins are suppressed at low temperatures and high magnetic fields. These conditions are suitable to stabilize the field-induced superconductivity by the field compensation mechanism. After the suppression of Fe-spin dynamics by a magnetic field of 19 T, we observed the underlying π -electron contribution. We discuss a possible anomaly in the π -electron system.

  16. Comparison of the grignard deacylation TLC and HPLC methods and high resolution 13C-NMR for the sn-2 positional analysis of triacylglycerols containing gamma-linolenic acid.

    PubMed

    Redden, P R; Lin, X; Horrobin, D F

    1996-01-25

    There is increasing evidence that the fatty acid, gamma-linolenic acid (GLA) is the effective component found in evening primrose oil (EPO) which has been shown to bring about clinical improvement in a number of disease conditions. The two major triacylglycerols (TAGs) in EPO are trilinolein (LLL) and a TAG species containing one GLA and two linoleic (LA) fatty acid chains. This latter TAG, called dilinoleoyl-mono-gamma-linolenin (DLMG or Oenotheral), makes up about 15% by weight of EPO and accounts for over one-half of the total amount of GLA present in EPO. Although DLMG is comprised of three possible isomers, the abbreviation is used to represent the naturally occurring mixture of these isomers. We have isolated DLMG from EPO and also prepared its three possible isomers, sn-GLL, sn-LGL and sn-LLG, and carried out the sn-2 positional analysis using three different approaches, namely, Grignard deacylation TLC and HPLC methods and high resolution 13C-NMR spectroscopy. The results of the sn-2 positional analysis for both the natural and synthetic TAGs containing LA and GLA in this study using the three approaches are all in very good agreement. This indicates that the three positional analysis methods are valid within their acceptable error margin and can be used with confidence in determining the fatty acid composition of the sn-2 position. Given the increased availability of NMR spectrometers this method might prove to be the easiest and most convenient in determining the sn-2 position for oil or TAG samples that contain a small number of different fatty acids providing all the 13C-NMR carbonyl resonances are well resolved.

  17. Quantum Chemical Study of the Solvent Effect on the Anticancer Active Molecule of Iproplatin: Structural, Electronic, and Spectroscopic Properties (IR, 1H NMR, UV)

    NASA Astrophysics Data System (ADS)

    Sadeghi, N.; Ghiasi, R.; Fazaeli, R.; Jamehbozorgi, S.

    2017-01-01

    The structural, electronic, and spectroscopic properties of the anticancer active molecule of iproplatin were investigated in the gas and liquid phases. Based on the polarizable continuum model (PCM), the solvent effect on the structural parameters, frontier orbitals, and spectroscopic parameters of the complex was investigated. The results indicate that the polarity of solvents plays a significant role in the structure and pro perties of the complex. 1H and 13C NMR chemical shifts were calculated using the Gauge-invariant atomic orbital (GIAO) method. Pt-Cl and Pt-OH bonds were investigated through a vibrational analysis. Moreover, time dependent density functional theory (TD-DFT) was used to calculate the energy, oscillatory strength, and wavelength absorption maximum (λmax) of electronic transitions and its nature within the complex.

  18. New lanthanide complexes for sensitized visible and near-IR light emission: synthesis, 1H NMR, and X-ray structural investigation and photophysical properties.

    PubMed

    Quici, Silvio; Marzanni, Giovanni; Forni, Alessandra; Accorsi, Gianluca; Barigelletti, Francesco

    2004-02-23

    We describe the syntheses, the 1H NMR studies in CD3OD and D2O as solvent, the X-ray characterization, and the luminescence properties in D2O solution of the two complexes Eu.1 and Er.1, where 1 is a dipartite ligand that includes (i) a 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid (DO3A) unit serving as hosting site for the metal center; and (ii) a phenanthroline unit which plays the role of light antenna for the sensitization process of the metal centered luminescence. In a previous report (Inorg. Chem. 2002, 41, 2777), we have shown that for Eu.1 there are no water molecules within the first coordination sphere. X-ray and 1H NMR results reported here are consistent with full saturation of the nine coordination sites within the Eu.1 and Er.1 complexes. In addition, these studies provide important details regarding the conformations, square antiprism (SAP) and twisted square antiprism (TSAP), adopted in solution by these complexes. The luminescence results are consistent with both an effective intersystem crossing (ISC) at the light absorbing phenanthroline unit (lambda(exc) = 278 nm) and an effective energy transfer (en) process from the phenanthroline donor to the cation acceptor (with unit or close to unit efficiency for both steps). In D2O solvent, the overall sensitization efficiency, phi(se), is 0.3 and 5 x 10(-6), for Eu.1 (main luminescence peaks at 585, 612, 699 nm) and Er.1 (luminescence peak at 1530 nm), respectively. The photophysical properties of both complexes are discussed with reference to their structural features as elucidated by the obtained 1H NMR and X-ray results.

  19. Analysis of the Composition of Lipid in Human Meibum from Normal Infants, Children, Adolescents, Adults, and Adults with Meibomian Gland Dysfunction Using 1H-NMR Spectroscopy

    PubMed Central

    Shrestha, Rashmi K.; Foulks, Gary N.; Yappert, Marta C.; Milliner, Sarah E.

    2011-01-01

    Purpose. This study represents a first step toward the evaluation of possible compositional differences in meibum from normal donors (Mn) and donors with meibomian gland dysfunction (Md) by 1H-NMR spectroscopy. The results highlight the applicability of 1H-NMR spectroscopy for the quantitative analysis of waxes, cholesteryl esters, and glycerides in meibum lipid (ML). Methods. Meibum was obtained from 41 normal donors and 51 donors with meibomian gland dysfunction (MGD). 1H-NMR spectroscopy was used to quantify the amount of waxes, glycerides, and cholesteryl esters in human meibum. Results. The relative amount of cholesteryl esters in Mn increased with age and was 40% (P < 0.05) lower in Md. Interestingly, the relative levels of cholesteryl esters in infant meibum were comparable to those in Md. The relative amounts of glycerides were not affected significantly by age or MGD. Conclusions. The changes in cholesteryl ester could be used as a molecular marker for MGD and could potentially be applied to follow the efficacy of drug therapy in the treatment of MGD. The similarity of the levels of cholesteryl esters in infant meibum and Md suggests that the relative amounts of these meibum components alone are unlikely to be responsible for the increased stability of the infant tear film and decreased stability of the tear film with MGD. This study reveals the complexity of human MLs and the changes that occur with age and disease. Understanding the factors that lead to such variations is of utmost relevance in the design of effective therapies. PMID:21849420

  20. 1H NMR z-spectra of acetate methyl in stretched hydrogels: Quantum-mechanical description and Markov chain Monte Carlo relaxation-parameter estimation

    NASA Astrophysics Data System (ADS)

    Shishmarev, Dmitry; Chapman, Bogdan E.; Naumann, Christoph; Mamone, Salvatore; Kuchel, Philip W.

    2015-01-01

    The 1H NMR signal of the methyl group of sodium acetate is shown to be a triplet in the anisotropic environment of stretched gelatin gel. The multiplet structure of the signal is due to the intra-methyl residual dipolar couplings. The relaxation properties of the spin system were probed by recording steady-state irradiation envelopes ('z-spectra'). A quantum-mechanical model based on irreducible spherical tensors formed by the three magnetically equivalent spins of the methyl group was used to simulate and fit experimental z-spectra. The multiple parameter values of the relaxation model were estimated by using a Bayesian-based Markov chain Monte Carlo algorithm.

  1. Imazalil-cyclomaltoheptaose (beta-cyclodextrin) inclusion complex: preparation by supercritical carbon dioxide and 13C CPMAS and 1H NMR characterization.

    PubMed

    Lai, Simona; Locci, Emanuela; Piras, Alessandra; Porcedda, Silvia; Lai, Adolfo; Marongiu, Bruno

    2003-10-10

    An inclusion complex between imazalil (IMZ), a selected fungicide, and cyclomaltoheptaose (beta-cyclodextrin, betaCD) was obtained using supercritical fluid carbon dioxide. The best preparation conditions were determined, and the inclusion complex was investigated by means of 1H NMR spectroscopy in aqueous solution and 13C CPMAS NMR spectroscopy in the solid state. Information on the geometry of the betaCD/IMZ complex was obtained from ROESY spectroscopy, while the dynamics of the inclusion complex in the kilohertz range was obtained from the proton spin-lattice relaxation times in the rotating frame, T(1rho) (1H).

  2. The 1H NMR method for the determination of the absolute configuration of 1,2,3-prim,sec,sec-triols.

    PubMed

    Lallana, Enrique; Freire, Félix; Seco, José Manuel; Quiñoa, Emilio; Riguera, Ricardo

    2006-09-28

    The absolute configuration of 1,2,3-prim,sec,sec-triols can be assigned by comparison of the 1H NMR spectra of the tris-(R)- and the tris-(S)-MPA ester derivatives. An experimental demonstration of this correlation with 24 triols of known absolute configuration and a protocol using two parameters-Deltadelta(RS)(H3) and the difference between Deltadelta RS (H2) and Deltadelta RS (H3) = absolute value (Delta(Deltadelta RS))-for its application to the determination of the absolute configuration of other triols are presented.

  3. 1H NMR-Based Metabolomic Analysis of Sub-Lethal Perfluorooctane Sulfonate Exposure to the Earthworm, Eisenia fetida, in Soil.

    PubMed

    Lankadurai, Brian P; Furdui, Vasile I; Reiner, Eric J; Simpson, André J; Simpson, Myrna J

    2013-08-27

    1H NMR-based metabolomics was used to measure the response of Eisenia fetida earthworms after exposure to sub-lethal concentrations of perfluorooctane sulfonate (PFOS) in soil. Earthworms were exposed to a range of PFOS concentrations (five, 10, 25, 50, 100 or 150 mg/kg) for two, seven and fourteen days. Earthworm tissues were extracted and analyzed by 1H NMR. Multivariate statistical analysis of the metabolic response of E. fetida to PFOS exposure identified time-dependent responses that were comprised of two separate modes of action: a non-polar narcosis type mechanism after two days of exposure and increased fatty acid oxidation after seven and fourteen days of exposure. Univariate statistical analysis revealed that 2-hexyl-5-ethyl-3-furansulfonate (HEFS), betaine, leucine, arginine, glutamate, maltose and ATP are potential indicators of PFOS exposure, as the concentrations of these metabolites fluctuated significantly. Overall, NMR-based metabolomic analysis suggests elevated fatty acid oxidation, disruption in energy metabolism and biological membrane structure and a possible interruption of ATP synthesis. These conclusions obtained from analysis of the metabolic profile in response to sub-lethal PFOS exposure indicates that NMR-based metabolomics is an excellent discovery tool when the mode of action (MOA) of contaminants is not clearly defined.

  4. Direct and real-time quantification of tenofovir release from pH-sensitive microparticles into simulated biological fluids using 1H-NMR

    PubMed Central

    Oyler, Nathan A.; Youan, Bi-Botti C.

    2014-01-01

    In vitro drug release evaluation is a very important step toward the quality control of nano- or micro-particular drug delivery systems. However, most quantitative techniques such as HPLC requires a dialysis membrane to separate the released free drug from these delivery systems, thus are not capable of direct detection and real-time quantification of the drug release. This study describes for the first time, a rapid, specific, and direct method for the real-time quantification of in vitro tenofovir (TNF) release from pH-sensitive microparticles using a Varian 400 MHZ 1H nuclear magnetic resonance (1H-NMR) spectrometer. Various analytical performance parameters such as linearity, precision, accuracy, limit of quantification (LOQ), limit of detection (LOD), and robustness were validated according to International Conference on Harmonization (ICH) guidelines. The in vitro release of TNF from microparticles in both simulated vaginal fluid (VFS) and the mixture (VSFS) of VFS and simulated semen fluid (SFS) was monitored and quantified in real-time using 1H-NMR. The capability of real-time quantification of in vitro drug release from microparticles not only provides a more accurate prediction of its biological behavior in vivo, but is also independent of potential interference from the dialysis membrane. PMID:24765652

  5. (1)H NMR-based metabolomics study on a goldfish model of Parkinson's disease induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).

    PubMed

    Lu, Zhaoguang; Wang, Junsong; Li, Minghui; Liu, Qingwang; Wei, Dandan; Yang, Minghua; Kong, Lingyi

    2014-11-05

    A goldfish (Carassius auratus) model of Parkinson's disease (PD) was constructed by a single dose of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) according to previously reported methods. Global metabolite changes in brain of the MPTP induced goldfish model of PD were investigated. (1)H NMR-based metabolomics combined with various statistical methods such as orthogonal partial least squares discriminant analysis (OPLS-DA) and two-dimensional statistical total correlation spectroscopy (2D-STOCSY) found significant increase of leucine, isoleucine, valine, alanine, alanylalanine, creatinine, myo-inositol, 18:2 fatty acid, total fatty acids, arachic alcohol, taurine and significant decrease of N-acetylaspartate, (phospho)creatine, (phospho)choline, betaine, glutamine, 3-hexenedioate, acetamide, malonate, isocitrate, scyllo-inositol, phosphatidylcholines, cholesterols, n-3 fatty acids, polyunsaturated fatty acids (PUFAs) in brain of MPTP induced PD goldfish. These disturbed metabolite levels were involved in oxidative stress, energy failure, neuronal cell injury and death, consistent with those observed in clinical PD patients, and rodents and primates model of PD, indicating that the acute MPTP model of goldfish was an ideal and valuable model for PD research. In addition, several unusual metabolites in brain were significantly changed between MPTP induced PD and control goldfish, which might also play an important role in the pathogenesis of PD. This study also demonstrated the applicability and potential of (1)H NMR-based metabolomics approach for evaluation of animal models of disease induced by chemicals, such as MPTP-induced PD goldfish.

  6. Proton Dynamics in the Anti-ferroelectric CsH3(SeO3)2 by using 1H NMR Measurements

    NASA Astrophysics Data System (ADS)

    Lee, Moohee; Ndiaye, B.; Kang, K.; Kim, H.; Sim, J.; Lim, Ae Ran

    2014-03-01

    1H NMR techniques have been employed on the anti-ferroelectric CsH3(SeO3)2 to measure spectrum, shift, T1 and T2 from 300 K down to 80 K at 4.85 T. The 1H NMR spectrum at 300 K shows a composite structure; one dominant broad peak and two small narrow peaks. From the temperature dependences of both intensity and T1 for each peak, we identify that the narrow peaks come from rapidly moving protons whereas the broad peaks originate from rigid protons. The spectra below 200 K show several peaks associated with six nonequivalent proton sites and also the T1 decays show a non-exponential curve coming from many proton sites. T1 is very long even at 300 K and becomes even longer at low temperature. By analyzing T1 decays with T1S and T1L, we confirm that 1/T1(T) show an activated behavior; the short component originates from proton dynamics with activation energy of ~ 140 K and the long component is associated with that of ~ 100 K. Further analysis suggests that some protons show an abrupt change in both shift and T1L across Tc and may be responsible for the phase transition.

  7. Theoretical and experimental study of inclusion complexes formed by isoniazid and modified β-cyclodextrins: 1H NMR structural determination and antibacterial activity evaluation.

    PubMed

    Teixeira, Milena G; de Assis, João V; Soares, Cássia G P; Venâncio, Mateus F; Lopes, Juliana F; Nascimento, Clebio S; Anconi, Cleber P A; Carvalho, Guilherme S L; Lourenço, Cristina S; de Almeida, Mauro V; Fernandes, Sergio A; de Almeida, Wagner B

    2014-01-09

    Me-β-cyclodextrin (Me-βCD) and HP-β-cyclodextrin (HP-βCD) inclusion complexes with isoniazid (INH) were prepared with the aim of modulating the physicochemical and biopharmaceutical properties of the guest molecule, a well-known antibuberculosis drug. The architectures of the complexes were initially proposed according to NMR data Job plot and ROESY followed by density functional theory (DFT) calculations of (1)H NMR spectra using the PBE1PBE functional and 6-31G(d,p) basis set, including the water solvent effect with the polarizable continuum model (PCM), for various inclusion modes, providing support for the experimental proposal. An analysis of the (1)H NMR chemical shift values for the isoniazid (H6',8' and H5',9') and cyclodextrins (H3,5) C(1)H hydrogens, which are known to be very adequately described by the DFT methodology, revealed them to be extremely useful, promptly confirming the inclusion complex formation. An included mode which describes Me-βCD partially enclosing the hydrazide group of the INH is predicted as the most favorable supramolecular structure that can be used to explain the physicochemical properties of the encapsulated drug. Antibacterial activity was also evaluated, and the results indicated the inclusion complexes are a potential strategy for tuberculosis treatment.

  8. Quality of farmed and wild sea bass lipids studied by (1)H NMR: usefulness of this technique for differentiation on a qualitative and a quantitative basis.

    PubMed

    Vidal, Natalia P; Manzanos, Maria J; Goicoechea, Encarnación; Guillén, Maria D

    2012-12-01

    Proton Nuclear Magnetic Resonance ((1)H NMR) spectroscopy was employed to study the lipids of farmed and wild European sea bass (Dicentrarchus labrax). This technique provided a great deal of detailed information on sea bass lipids composition and, once the spectra signals have been assigned, the simple observation of the spectra enables one to distinguish cultured from wild fish. This distinction is possible due to the presence in the former of high proportions of diunsaturated acyl groups, mainly linoleic. Furthermore, new approaches for quantitative characterization of sea bass lipids were developed. For the same season wild sea bass lipids contain not only higher molar percentages of omega-3 and of docosahexaenoic (DHA), but also higher concentrations of phosphatidylcholine and of cholesterol than farmed ones. However, in general, the absolute content of DHA and of eicosapentaenoic plus arachidonic (EPA+ARA) acyl groups as well as of phosphatidylcholine and cholesterol, were reasonably higher in farmed than in wild sea bass fillets, due to the higher total lipid content of the former. The presence of omega-1 acyl groups in all farmed samples and in some of the wild specimens was shown. As far as we know, this is the first time that omega-1 acyl groups have been identified and quantified in fish lipids by (1)H NMR.

  9. (1)H NMR-Based Metabolomics and Neurotoxicity Study of Cerebrum and Cerebellum in Rats Treated with Cinnabar, a Traditional Chinese Medicine.

    PubMed

    Wei, Lai; Xue, Rong; Zhang, Panpan; Wu, Yijie; Li, Xiaojing; Pei, Fengkui

    2015-08-01

    Cinnabar, an important traditional Chinese mineral medicine, has been widely used as a Chinese patent medicine ingredient for sedative therapy. Nevertheless, the neurotoxic effects of cinnabar have also been noted. In this study, (1)H NMR-based metabolomics, combined with multivariate pattern recognition, were applied to investigate the neurotoxic effects of cinnabar after intragastrical administration (dosed at 2 and 5 g/kg body weight) on male Wistar rats. The metabolite variations induced by cinnabar were characterized by increased levels of glutamate, glutamine, myo-inositol, and choline, as well as decreased levels of GABA, taurine, NAA, and NAAG in tissue extracts of the cerebellum and cerebrum. These findings suggested that cinnabar induced glutamate excitotoxicity, neuronal cell loss, osmotic state changes, membrane fluidity disruption, and oxidative injury in the brain. We also show here that there is a dose- and time-dependent neurotoxicity of cinnabar, and that cerebellum was more sensitive to cinnabar induction than cerebrum. This work illustrates the utility and reliability of (1)H NMR-based metabolomics approach for examining the potential neurotoxic effects of cinnabar and other traditional Chinese medicines.

  10. 1H NMR-Based Metabolomic Analysis of Sub-Lethal Perfluorooctane Sulfonate Exposure to the Earthworm, Eisenia fetida, in Soil

    PubMed Central

    Lankadurai, Brian P.; Furdui, Vasile I.; Reiner, Eric J.; Simpson, André J.; Simpson, Myrna J.

    2013-01-01

    1H NMR-based metabolomics was used to measure the response of Eisenia fetida earthworms after exposure to sub-lethal concentrations of perfluorooctane sulfonate (PFOS) in soil. Earthworms were exposed to a range of PFOS concentrations (five, 10, 25, 50, 100 or 150 mg/kg) for two, seven and fourteen days. Earthworm tissues were extracted and analyzed by 1H NMR. Multivariate statistical analysis of the metabolic response of E. fetida to PFOS exposure identified time-dependent responses that were comprised of two separate modes of action: a non-polar narcosis type mechanism after two days of exposure and increased fatty acid oxidation after seven and fourteen days of exposure. Univariate statistical analysis revealed that 2-hexyl-5-ethyl-3-furansulfonate (HEFS), betaine, leucine, arginine, glutamate, maltose and ATP are potential indicators of PFOS exposure, as the concentrations of these metabolites fluctuated significantly. Overall, NMR-based metabolomic analysis suggests elevated fatty acid oxidation, disruption in energy metabolism and biological membrane structure and a possible interruption of ATP synthesis. These conclusions obtained from analysis of the metabolic profile in response to sub-lethal PFOS exposure indicates that NMR-based metabolomics is an excellent discovery tool when the mode of action (MOA) of contaminants is not clearly defined. PMID:24958147

  11. Revealing Potential Biomarkers of Functional Dyspepsia by Combining 1H NMR Metabonomics Techniques and an Integrative Multi-objective Optimization Method.

    PubMed

    Wu, Qiaofeng; Zou, Meng; Yang, Mingxiao; Zhou, Siyuan; Yan, Xianzhong; Sun, Bo; Wang, Yong; Chang, Shyang; Tang, Yong; Liang, Fanrong; Yu, Shuguang

    2016-01-08

    Metabonomics methods have gradually become important auxiliary tools for screening disease biomarkers. However, recognition of metabolites or potential biomarkers closely related to either particular clinical symptoms or prognosis has been difficult. The current study aims to identify potential biomarkers of functional dyspepsia (FD) by a new strategy that combined hydrogen nuclear magnetic resonance ((1)H NMR)-based metabonomics techniques and an integrative multi-objective optimization (LPIMO) method. First, clinical symptoms of FD were evaluated using the Nepean Dyspepsia Index (NDI), and plasma metabolic profiles were measured by (1)H NMR. Correlations between the key metabolites and the NDI scores were calculated. Then, LPIMO was developed to identify a multi-biomarker panel by maximizing diagnostic ability and correlation with the NDI score. Finally, a KEGG database search elicited the metabolic pathways in which the potential biomarkers are involved. The results showed that glutamine, alanine, proline, HDL, β-glucose, α-glucose and LDL/VLDL levels were significantly altered in FD patients. Among them, phosphatidycholine (PtdCho) and leucine/isoleucine (Leu/Ile) were positively and negatively correlated with the NDI Symptom Index (NDSI) respectively. Our procedure not only significantly improved the credibility of the biomarkers, but also demonstrated the potential of further explorations and applications to diagnosis and treatment of complex disease.

  12. Local spin dynamics of iron oxide magnetic nanoparticles dispersed in different solvents with variable size and shape: A 1H NMR study

    NASA Astrophysics Data System (ADS)

    Basini, M.; Orlando, T.; Arosio, P.; Casula, M. F.; Espa, D.; Murgia, S.; Sangregorio, C.; Innocenti, C.; Lascialfari, A.

    2017-01-01

    Colloidal magnetic nanoparticles (MNPs) based on a nearly monodisperse iron oxide core and capped by oleic acid have been used as model systems for investigating the superparamagnetic spin dynamics by means of magnetometry measurements and nuclear magnetic resonance (1H NMR) relaxometry. The key magnetic properties (saturation magnetization, coercive field, and frequency dependent "blocking" temperature) of MNPs with different core size (3.5 nm, 8.5 nm, and 17.5 nm), shape (spherical and cubic), and dispersant (hexane and water-based formulation) have been determined. 1H NMR dispersion profiles obtained by measuring the r1 (longitudinal) and r2 (transverse) nuclear relaxivities in the frequency range 0.01-60 MHz confirmed that in all samples the physical mechanisms that drive the nuclear relaxation are the Néel reversal at low temperature and the Curie relaxation at high frequency. The magnetization reversal time at room temperature extracted from the fitting of NMR data falls in the typical range of superparamagnetic systems (10-9-10-10 s). Furthermore, from the distance of minimum approach we could conclude that water molecules do not arrive in close vicinity of the magnetic core. Our findings contribute to elucidate the local spin dynamics mechanisms in colloidal superparamagnetic nanoparticles which are useful in biomedical application as, e.g., contrast agents for magnetic resonance imaging.

  13. Revealing Potential Biomarkers of Functional Dyspepsia by Combining 1H NMR Metabonomics Techniques and an Integrative Multi-objective Optimization Method

    PubMed Central

    Wu, Qiaofeng; Zou, Meng; Yang, Mingxiao; Zhou, Siyuan; Yan, Xianzhong; Sun, Bo; Wang, Yong; Chang, Shyang; Tang, Yong; Liang, Fanrong; Yu, Shuguang

    2016-01-01

    Metabonomics methods have gradually become important auxiliary tools for screening disease biomarkers. However, recognition of metabolites or potential biomarkers closely related to either particular clinical symptoms or prognosis has been difficult. The current study aims to identify potential biomarkers of functional dyspepsia (FD) by a new strategy that combined hydrogen nuclear magnetic resonance (1H NMR)-based metabonomics techniques and an integrative multi-objective optimization (LPIMO) method. First, clinical symptoms of FD were evaluated using the Nepean Dyspepsia Index (NDI), and plasma metabolic profiles were measured by 1H NMR. Correlations between the key metabolites and the NDI scores were calculated. Then, LPIMO was developed to identify a multi-biomarker panel by maximizing diagnostic ability and correlation with the NDI score. Finally, a KEGG database search elicited the metabolic pathways in which the potential biomarkers are involved. The results showed that glutamine, alanine, proline, HDL, β-glucose, α-glucose and LDL/VLDL levels were significantly altered in FD patients. Among them, phosphatidycholine (PtdCho) and leucine/isoleucine (Leu/Ile) were positively and negatively correlated with the NDI Symptom Index (NDSI) respectively. Our procedure not only significantly improved the credibility of the biomarkers, but also demonstrated the potential of further explorations and applications to diagnosis and treatment of complex disease. PMID:26743458

  14. Quantitative analysis of four major diterpenoids in Andrographis paniculata by 1H NMR and its application for quality control of commercial preparations.

    PubMed

    Yang, Minghua; Wang, Junsong; Kong, Lingyi

    2012-11-01

    A quantitative proton nuclear magnetic resonance technique (qHNMR) has been successfully introduced to quantify andrographolide, dehydroandrographolide, deoxyandrographolide and neoandrographolide in Andrographis paniculata, a commonly used important traditional Chinese medicine. Creative use of trifluoroacetic acid-d, which satisfactorily resolved the overlapping signals of these compounds in crowded regions of δ 4.5-5.6 ppm in (1)H NMR spectrum, made their quantification possible. Optimization of other experimental conditions, including internal standard, NMR pulse sequence, and NMR relaxation delay time, finally established the (1)H NMR based quantification approach, which was validated with satisfactory accuracy, precision, repeatability, and recovery. Except for deoxyandrographolide and neoandrographolide in two compound recipes, this method was successfully applied to quantify the four major components in fourteen raw herb materials and five commercial preparations, providing quantification results in good agreement with those determined by HPLC. The inherent advantages of qHNMR, such as its rapidity and simplicity, make itself a feasible alternative to HPLC for the quality control of A. paniculata raw material and herbal preparations.

  15. Application of 1H NMR spectroscopy method for determination of characteristics of thin layers of water adsorbed on the surface of dispersed and porous adsorbents.

    PubMed

    Turov, V V; Leboda, R

    1999-02-01

    The paper presents 1H NMR spectroscopy as a perspective method of the studies of the characteristics of water boundary layers in the hydrated powders and aqueous dispergated suspensions of the adsorbents. The method involves measurements of temperature dependence proton signals intensity in the adsorbed water at temperatures lower than 273 K. Free energy of water molecules at the adsorbent/water interface is diminished due to the adsorption interactions causing the water dosed to the adsorbent surface freezes at T < 273 K. Thickness of a non-freezing layer of water can be determined from the intensity of the water signal of 1H NMR during the freezing-thawing process. Due to a disturbing action of the adsorbent surface, water occurs in the quasi-liquid state. As a result, it is observed in the 1H NMR spectra as a relatively narrow signal. The signal of ice is not registered due to great differences in the transverse relaxation times of the adsorbed water and ice. The method of measuring the free surface energy of the adsorbents from the temperature dependence of the signal intensity of non-freezing water is based on the fact that the temperature of water freezing decreases by the quantity which depends on the surface energy and the distance of the adsorbed molecules from the solid surface. The water at the interface freezes when the free energies of the adsorbed water and ice are equal. To illustrate the applicability of the method under consideration the series of adsorption systems in which the absorbents used differed in the surface chemistry and porous structure. In particular, the behaviour of water on the surface of the following adsorbents is discussed: non-porous and porous silica (aerosils, silica gels); chemically and physically modified non-porous and porous silica (silanization, carbonization, biopolymer deposition); and pyrogeneous Al2O3 and aluminasilicas. The effect of preliminary treatment of the adsorbent (thermal, high pressure, wetting with polar

  16. 1H NMR Metabolomics Reveals Association of High Expression of Inositol 1, 4, 5 Trisphosphate Receptor and Metabolites in Breast Cancer Patients

    PubMed Central

    Chagtoo, Megha; Agarwal, Gaurav; George, Nelson; Sinha, Neeraj; Godbole, Madan M.

    2017-01-01

    1H NMR is used to detect alterations in metabolites and their linkage to metabolic processes in a number of pathological conditions including breast cancer. Inositol 1, 4, 5 trisphosphate (IP3R) receptor is an intracellular calcium channel known to regulate metabolism and cellular bioenergetics. Its expression is up regulated in a number of cancers. However, its linkage to metabolism in disease conditions has not been evaluated. This study was designed to determine the association if any, of these metabolites with altered expression of IP3R in breast cancer. We used 1H NMR to identify metabolites in the serum of breast cancer patients (n = 27) and performed Real-time Polymerase Chain Reaction analysis for quantifying the expression of IP3R type 3 and type 2 in tissues from breast cancer patients (n = 40). Principal Component Analysis (PCA) and Partial Least Square-Discriminant Analysis (PLS-DA) clearly distinguished patients with high/low IP3R expression from healthy subjects. The present study revealed high expression of IP3R type 2 and type 3 in human breast tumor tissue compared to adjacent non-tumorous tissue. Moreover, patients with ≥ 2-fold increase in IP3R (high IP3R group) had significantly higher concentration of metabolic intermediates compared to those with < 2-fold increase in IP3R (low IP3R group). We observed an increase in lipoprotein content and the levels of metabolites like lactate, lysine and alanine and a decrease in the levels of pyruvate and glucose in serum of high IP3R group patients when compared to those in healthy subjects. Receiver operating characteristic (ROC) curve analysis was performed to show the clinical utility of metabolites. In addition to the human studies, functional relevance of IP3Rs in causing metabolic disruption was observed in MCF-7 and MDA MB-231 cells. Results from our studies bring forth the importance of metabolic (or metabolomics) profiling of serum by 1H NMR in conjunction with tissue expression studies for

  17. Analysis of commercial proanthocyanidins. Part 4: solid state (13)C NMR as a tool for in situ analysis of proanthocyanidin tannins, in heartwood and bark of quebracho and acacia, and related species.

    PubMed

    Reid, David G; Bonnet, Susan L; Kemp, Gabre; van der Westhuizen, Jan H

    2013-10-01

    (13)C NMR is an effective method of characterizing proanthocyanidin (PAC) tannins in quebracho (Schinopsis lorentzii) heartwood and black wattle (Acacia mearnsii) bark, before and after commercial extraction. The B-rings of the constituent flavan-3-ols, catechols (quebracho) or pyrogallols (wattle), are recognized in unprocessed source materials by "marker" signals at ca. 118 or 105ppm, respectively. NMR allows the minimum extraction efficiency to be calculated; ca. 30%, and ca. 80%, for quebracho heartwood and black wattle bark, respectively. NMR can also identify PAC tannin (predominantly robinetinidin), and compare tannin content, in bark from other acacia species; tannin content decreases in the order A. mearnsii, Acacia pycnantha (87% of A. mearnsii), Acacia dealbata and Acacia decurrens (each 74%) and Acacia karroo (30%). Heartwood from an underexploited PAC tannin source, Searsia lancea, taxonomically close to quebracho, shows abundant profisetinidin and catechin PACs. NMR offers the advantage of being applicable to source materials in their native state, and has potential applications in optimizing extraction processes, identification of tannin sources, and characterization of tannin content in cultivar yield improvement programmes.

  18. Spectroscopic (FT-IR, FT-Raman, UV absorption, 1H and 13C NMR) and theoretical (in B3LYP/6-311++G** level) studies on alkali metal salts of caffeic acid

    NASA Astrophysics Data System (ADS)

    Świsłocka, Renata

    The effect of some metals on the electronic system of benzoic and nicotinic acids has recently been investigated by IR, Raman and UV spectroscopy [1-3]. Benzoic and nicotinic acids are regarded model systems representing a wide group of aromatic ligands which are incorporated into enzymes. In this work the FT-IR (in solid state and in solution), FT-Raman, UV absorption and 1H and 13C NMR spectra of caffeic acid (3,4-dihydroxycinnamic acid) and its salts with lithium, sodium, potassium, rubidium and caesium were registered, assigned and analyzed. The effect of alkali metals on the electronic system of ligands was discussed. Studies of differences in the number and position of bands from the IR, Raman, UV absorption spectra and chemical shifts from NMR spectra allowed to conclude on the distribution of electronic charge in the molecules, the delocalization energy of π electrons and the reactivity of ligands in metal complexes. Optimized geometrical structures of studied compounds were calculated by B3LYP method using 6-311++G** basis set. Bond lengths, angles and dipole moments for the optimized structures of caffeic acid and lithium, sodium, potassium caffeinates were also calculated. The theoretical wavenumbers and intensities of IR spectra were obtained. The calculated parameters were compared to the experimental characteristics of investigated compounds. Microbial activity of studied compounds was tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Proteus vulgaris.

  19. Powder X-ray diffraction, infrared and (13)C NMR spectroscopic studies of the homologous series of some solid-state zinc(II) and sodium(I) n-alkanoates.

    PubMed

    Nelson, Peter N; Taylor, Richard A

    2015-03-05

    A comparative study of the room temperature molecular packing and lattice structures for the homologous series of zinc(II) and sodium(I) n-alkanoates adduced from Fourier transform infrared and solid-state (13)C NMR spectroscopic data in conjunction with X-ray powder diffraction measurements is carried out. For zinc carboxylates, metal-carboxyl bonding is via asymmetric bridging bidentate coordination whilst for the sodium adducts, coordination is via asymmetric chelating bidentate bonding. All compounds are packed in a monoclinic crystal system. Furthermore, the fully extended all-trans hydrocarbon chains are arranged as lamellar bilayers. For zinc compounds, there is bilayer overlap, for long chain adducts (nc>8) but not for sodium compounds where methyl groups from opposing layers in the lamellar are only closely packed. Additionally, the hydrocarbon chains are extended along the a-axis of the unit cell for zinc compounds whilst for sodium carboxylates they are extended along the c-axis. These packing differences are responsible for different levels of Van der Waals effects in the lattices of these two series of compounds, hence, observed odd-even alternation is different. The significant difference in lattice packing observed for these two series of compounds is proposed to be due to the difference in metal-carboxyl coordination mode, arising from the different electronic structure of the central metal ions.

  20. Comprehensive quantum chemical and spectroscopic (FTIR, FT-Raman, (1)H, (13)C NMR) investigations of (1,2-epoxyethyl)benzene and (1,2-epoxy-2-phenyl)propane.

    PubMed

    Arjunan, V; Anitha, R; Devi, L; Mohan, S; Yang, Haifeng

    2015-01-25

    Aromatic epoxides are causative factors for mutagenic and carcinogenic activity of polycyclic arenes. The 1,2- or 2,3-epoxy compounds are widely used to a considerable extent in the textile, plastics, pharmaceutical, cosmetics, detergent and photochemical industries. The FTIR and FT-Raman spectra of (1,2-epoxyethyl)benzene and (1,2-epoxy-2-phenyl)propane are recorded in the regions 4000-400 cm(-1) and 4000-100 cm(-1), respectively. The observed fundamentals are assigned to different normal modes of vibration. The structure of the compound has been optimised with B3LYP method using 6-311++G(**) and cc-pVTZ basis sets. The IR and Raman intensities are determined. The total electron density and molecular electrostatic potential surfaces of the molecule are constructed by using B3LYP/6-311++G(d,p) method to display electrostatic potential (electron+nuclei) distribution. The electronic properties HOMO and LUMO energies were measured. Natural bond orbital analysis of the compounds has been performed to indicate the presence of intramolecular charge transfer. The (1)H and (13)C NMR chemical shifts of the molecules have been analysed.

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