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Sample records for 31p nmr analysis

  1. Comparison of phosphorus forms in three extracts of dairy feces by solution 31P NMR analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using solution 31P NMR spectroscopy, we compared three extractants, deionized water, sodium acetate buffer (pH 5.0) with fresh sodium dithionite (NaAc-SD), and 0.25 M NaOH-0.05 M EDTA (NaOH-EDTA), for the profile of P compounds in two dairy fecal samples. Phosphorus extracted was 35% for water, and...

  2. Pyrolysis temperature affects phosphorus transformation in biochar: Chemical fractionation and (31)P NMR analysis.

    PubMed

    Xu, Gang; Zhang, You; Shao, Hongbo; Sun, Junna

    2016-11-01

    Phosphorus (P) recycling or reuse by pyrolyzing crop residue has recently elicited increased research interest. However, the effects of feedstock and pyrolysis conditions on P species have not been fully understood. Such knowledge is important in identifying the agronomic and environmental uses of biochar. Residues of three main Chinese agricultural crops and the biochars (produced at 300°C-600°C) derived from these crops were used to determine P transformations during pyrolysis. Hedley sequential fractionation and (31)P NMR analyses were used in the investigation. Our results showed that P transformation in biochar was significantly affected by pyrolysis temperature regardless of feedstock (Wheat straw, maize straw and peanut husk). Pyrolysis treatment transformed water soluble P into a labile (NaHCO3-Pi) or semi-labile pool (NaOH-Pi) and into a stable pool (Dil. HCl P and residual-P). At the same time, organic P was transformed into inorganic P fractions which was identified by the rapid decomposition of organic P detected with solution (31)P NMR. The P transformation during pyrolysis process suggested more stable P was formed at a higher pyrolysis temperature. This result was also evidenced by the presence of less soluble or stable P species, such as such as poly-P, crandallite (CaAl3(OH)5(PO4)2) and Wavellite (Al3(OH)3(PO4)2·5H2O), as detected by solid-state (31)P NMR in biochars formed at a higher pyrolysis temperature. Furthermore, a significant proportion of less soluble pyrophosphate was identified by solution (2%-35%) and solid-state (8%-53%) (31)P NMR, which was also responsible for the stable P forms at higher pyrolysis temperature although their solubility or stability requires further investigation. Results suggested that a relatively lower pyrolysis temperature retains P availability regardless of feedstock during pyrolysis process.

  3. Crystallinity and compositional changes in carbonated apatites: Evidence from {sup 31}P solid-state NMR, Raman, and AFM analysis

    SciTech Connect

    McElderry, John-David P.; Zhu, Peizhi; Mroue, Kamal H.; Xu, Jiadi; Pavan, Barbara; Fang, Ming; Zhao, Guisheng; McNerny, Erin; Kohn, David H.; Franceschi, Renny T.; Holl, Mark M.Banaszak; Tecklenburg, Mary M.J.; Ramamoorthy, Ayyalusamy; Morris, Michael D.

    2013-10-15

    Solid-state (magic-angle spinning) NMR spectroscopy is a useful tool for obtaining structural information on bone organic and mineral components and synthetic model minerals at the atomic-level. Raman and {sup 31}P NMR spectral parameters were investigated in a series of synthetic B-type carbonated apatites (CAps). Inverse {sup 31}P NMR linewidth and inverse Raman PO{sub 4}{sup 3−}ν{sub 1} bandwidth were both correlated with powder XRD c-axis crystallinity over the 0.3–10.3 wt% CO{sub 3}{sup 2−} range investigated. Comparison with bone powder crystallinities showed agreement with values predicted by NMR and Raman calibration curves. Carbonate content was divided into two domains by the {sup 31}P NMR chemical shift frequency and the Raman phosphate ν{sub 1} band position. These parameters remain stable except for an abrupt transition at 6.5 wt% carbonate, a composition which corresponds to an average of one carbonate per unit cell. This near-binary distribution of spectroscopic properties was also found in AFM-measured particle sizes and Ca/P molar ratios by elemental analysis. We propose that this transition differentiates between two charge-balancing ion-loss mechanisms as measured by Ca/P ratios. These results define a criterion for spectroscopic characterization of B-type carbonate substitution in apatitic minerals. - Graphical abstract: Carbonated apatite shows an abrupt change in spectral (NMR, Raman) and morphological (AFM) properties at a composition of about one carbonate substitution per unit cell. Display Omitted - Highlights: • Crystallinity (XRD), particle size (AFM) of carbonated apatites and bone mineral. • Linear relationships among crystallinity, {sup 31}P NMR and Raman inverse bandwidths. • Low and high carbonated apatites use different charge-balancing ion-loss mechanism.

  4. Crystallinity and compositional changes in carbonated apatites: Evidence from 31P solid-state NMR, Raman, and AFM analysis

    PubMed Central

    McElderry, John-David P.; Zhu, Peizhi; Mroue, Kamal H.; Xu, Jiadi; Pavan, Barbara; Fang, Ming; Zhao, Guisheng; McNerny, Erin; Kohn, David H.; Franceschi, Renny T.; Holl, Mark M. Banaszak; Tecklenburg, Mary M.J.; Ramamoorthy, Ayyalusamy; Morris, Michael D.

    2013-01-01

    Solid-state (magic-angle spinning) NMR spectroscopy is a useful tool for obtaining structural information on bone organic and mineral components and synthetic model minerals at the atomic-level. Raman and 31P NMR spectral parameters were investigated in a series of synthetic B-type carbonated apatites (CAps). Inverse 31P NMR linewidth and inverse Raman PO43− ν1 bandwidth were both correlated with powder XRD c-axis crystallinity over the 0.3–10.3 wt% CO32− range investigated. Comparison with bone powder crystallinities showed agreement with values predicted by NMR and Raman calibration curves. Carbonate content was divided into two domains by the 31P NMR chemical shift frequency and the Raman phosphate ν1 band position. These parameters remain stable except for an abrupt transition at 6.5 wt% carbonate, a composition which corresponds to an average of one carbonate per unit cell. This near-binary distribution of spectroscopic properties was also found in AFM-measured particle sizes and Ca/P molar ratios by elemental analysis. We propose that this transition differentiates between two charge-balancing ion-loss mechanisms as measured by Ca/P ratios. These results define a criterion for spectroscopic characterization of B-type carbonate substitution in apatitic minerals. PMID:24273344

  5. Analysis of monoglycerides, diglycerides, sterols, and free fatty acids in coconut (Cocos nucifera L.) oil by 31P NMR spectroscopy.

    PubMed

    Dayrit, Fabian M; Buenafe, Olivia Erin M; Chainani, Edward T; de Vera, Ian Mitchelle S

    2008-07-23

    Phosphorus-31 nuclear magnetic resonance spectroscopy ( (31)P NMR) was used to differentiate virgin coconut oil (VCO) from refined, bleached, deodorized coconut oil (RCO). Monoglycerides (MGs), diglycerides (DGs), sterols, and free fatty acids (FFAs) in VCO and RCO were converted into dioxaphospholane derivatives and analyzed by (31)P NMR. On the average, 1-MG was found to be higher in VCO (0.027%) than RCO (0.019%). 2-MG was not detected in any of the samples down to a detection limit of 0.014%. On the average, total DGs were lower in VCO (1.55%) than RCO (4.10%). When plotted in terms of the ratio [1,2-DG/total DGs] versus total DGs, VCO and RCO samples grouped separately. Total sterols were higher in VCO (0.096%) compared with RCO (0.032%), and the FFA content was 8 times higher in VCO than RCO (0.127% vs 0.015%). FFA determination by (31)P NMR and titration gave comparable results. Principal components analysis shows that the 1,2-DG, 1,3-DG, and FFAs are the most important parameters for differentiating VCO from RCO.

  6. Analysis of 31P MAS NMR spectra and transversal relaxation of bacteriophage M13 and tobacco mosaic virus.

    PubMed Central

    Magusin, P C; Hemminga, M A

    1994-01-01

    Phosphorus magic angle spinning nuclear magnetic resonance (NMR) spectra and transversal relaxation of M13 and TMV are analyzed by use of a model, which includes both local backbone motions of the encapsulated nucleic acid molecules and overall rotational diffusion of the rod-shaped virions about their length axis. Backbone motions influence the sideband intensities by causing a fast restricted reorientation of the phosphodiesters. To evaluate their influence on the observed sideband patterns, we extend the model that we used previously to analyze nonspinning 31P NMR lineshapes (Magusin, P.C.M.M., and M. A. Hemminga. 1993a. Biophys. J. 64:1861-1868) to magic angle spinning NMR experiments. Backbone motions also influence the conformation of the phosphodiesters, causing conformational averaging of the isotropic chemical shift, which offers a possible explanation for the various linewidths of the centerband and the sidebands observed for M13 gels under various conditions. The change of the experimental lineshape of M13 as a function of temperature and hydration is interpreted in terms of fast restricted fluctuation of the dihedral angles between the POC and the OCH planes on both sides of the 31P nucleus in the nucleic acid backbone. Backbone motions also seem to be the main cause of transversal relaxation measured at spinning rates of 4 kHz or higher. At spinning rates less than 2 kHz, transversal relaxation is significantly faster. This effect is assigned to slow, overall rotation of the rod-shaped M13 phage about its length axis. Equations are derived to simulate the observed dependence of T2e on the spinning rate. PMID:8038391

  7. The effect of ethanol on hydroxyl and carbonyl groups in biopolyol produced by hydrothermal liquefaction of loblolly pine: (31)P-NMR and (19)F-NMR analysis.

    PubMed

    Celikbag, Yusuf; Via, Brian K; Adhikari, Sushil; Buschle-Diller, Gisela; Auad, Maria L

    2016-08-01

    The goal of this study was to investigate the role of ethanol and temperature on the hydroxyl and carbonyl groups in biopolyol produced from hydrothermal liquefaction of loblolly pine (Pinus spp.) carried out at 250, 300, 350 and 390°C for 30min. Water and water/ethanol mixture (1/1, wt/wt) were used as liquefying solvent in the HTL experiments. HTL in water and water/ethanol is donated as W-HTL and W/E-HTL, respectively. It was found that 300°C and water/ethanol solvent was the optimum liquefaction temperature and solvent, yielding up to 68.1wt.% bio-oil and 2.4wt.% solid residue. (31)P-NMR analysis showed that biopolyol produced by W-HTL was rich in phenolic OH while W/E-HTL produced more aliphatic OH rich biopolyols. Moreover, biopolyols with higher hydroxyl concentration were produced by W/E-HTL. Carbonyl groups were analyzed by (19)F-NMR, which showed that ethanol reduced the concentration of carbonyl groups. PMID:27126078

  8. The effect of ethanol on hydroxyl and carbonyl groups in biopolyol produced by hydrothermal liquefaction of loblolly pine: (31)P-NMR and (19)F-NMR analysis.

    PubMed

    Celikbag, Yusuf; Via, Brian K; Adhikari, Sushil; Buschle-Diller, Gisela; Auad, Maria L

    2016-08-01

    The goal of this study was to investigate the role of ethanol and temperature on the hydroxyl and carbonyl groups in biopolyol produced from hydrothermal liquefaction of loblolly pine (Pinus spp.) carried out at 250, 300, 350 and 390°C for 30min. Water and water/ethanol mixture (1/1, wt/wt) were used as liquefying solvent in the HTL experiments. HTL in water and water/ethanol is donated as W-HTL and W/E-HTL, respectively. It was found that 300°C and water/ethanol solvent was the optimum liquefaction temperature and solvent, yielding up to 68.1wt.% bio-oil and 2.4wt.% solid residue. (31)P-NMR analysis showed that biopolyol produced by W-HTL was rich in phenolic OH while W/E-HTL produced more aliphatic OH rich biopolyols. Moreover, biopolyols with higher hydroxyl concentration were produced by W/E-HTL. Carbonyl groups were analyzed by (19)F-NMR, which showed that ethanol reduced the concentration of carbonyl groups.

  9. 31P NMR analysis of intracellular pH of Swiss Mouse 3T3 cells: effects of extracellular Na+ and K+ and mitogenic stimulation.

    PubMed

    Civan, M M; Williams, S R; Gadian, D G; Rozengurt, E

    1986-01-01

    Swiss mouse 3T3 cells grown on microcarrier beads were superfused with electrolyte solution during continuous NMR analysis. Conventional 31P and 19F probes of intracellular pH (pHc) were found to be impracticable. Cells were therefore superfused with 1 to 4 mM 2-deoxyglucose, producing a large intracellular, pH-sensitive signal of 2-deoxyglucose phosphate (2DGP). The intracellular incorporation of 2DGP inhibited the Embden-Meyerhof pathway. However, intracellular ATP was at least in part retained and the cellular responsivity to changes in extracellular ionic composition and to the application of growth factors proved intact. Transient replacement of external Na+ with choline or K+ reversibly acidified the intracellular fluids. Quiescent cells and mitogenically stimulated cells displayed the same dependence of shifts in pHc on external Na+ concentration (CoNa). PHc also depended on intracellular Na+ concentration (CcNa). Increasing ccNa by withdrawing external K+ (thereby inhibiting the Na,K-pump) caused reversible intracellular acidification; subsequently reducing CoNa produced a larger acid shift in pHc than with external K+ present. Comparison of separate preparations indicated that pHc was higher in stimulated than in quiescent cells. Transient administration of mitogens also reversibly alkalinized quiescent cells studied continuously. This study documents the feasibility of monitoring pHc of Swiss mouse 3T3 cells using 31P NMR analysis of 2DGP. The results support the concept of a Na/H antiport operative in these cells, both in quiescence and after mitogenic stimulation. The data document by an independent technique that cytoplasmic alkalinization is an early event in mitogenesis, and that full activity of the Embden-Meyerhof pathway is not required for the expression of this event.

  10. Human in vivo phosphate metabolite imaging with 31P NMR.

    PubMed

    Bottomley, P A; Charles, H C; Roemer, P B; Flamig, D; Engeseth, H; Edelstein, W A; Mueller, O M

    1988-07-01

    Phosphorus (31P) spectroscopic images showing the distribution of high-energy phosphate metabolites in the human brain have been obtained at 1.5 T in scan times of 8.5 to 34 min at 27 and 64 cm3 spatial resolution using pulsed phase-encoding gradient magnetic fields and three-dimensional Fourier transform (3DFT) techniques. Data were acquired as free induction decays with a quadrature volume NMR detection coil of a truncated geometry designed to optimize the signal-to-noise ratio on the coil axis on the assumption that the sample noise represents the dominant noise source, and self-shielded magnetic field gradient coils to minimize eddy-current effects. The images permit comparison of metabolic data acquired simultaneously from different locations in the brain, as well as metabolite quantification by inclusion of a vial containing a standard of known 31P concentration in the image array. Values for the NMR visible adenosine triphosphate in three individuals were about 3 mM of tissue. The ratio of NMR detectable phosphocreatine to ATP in brain was 1.15 +/- 0.17 SD in these experiments. Potential sources of random and systematic error in these and other 31P measurements are identified.

  11. Geographical characterization of greek virgin olive oils (cv. Koroneiki) using 1H and 31P NMR fingerprinting with canonical discriminant analysis and classification binary trees.

    PubMed

    Petrakis, Panos V; Agiomyrgianaki, Alexia; Christophoridou, Stella; Spyros, Apostolos; Dais, Photis

    2008-05-14

    This work deals with the prediction of the geographical origin of monovarietal virgin olive oil (cv. Koroneiki) samples from three regions of southern Greece, namely, Peloponnesus, Crete, and Zakynthos, and collected in five harvesting years (2001-2006). All samples were chemically analyzed by means of 1H and 31P NMR spectroscopy and characterized according to their content in fatty acids, phenolics, diacylglycerols, total free sterols, free acidity, and iodine number. Biostatistical analysis showed that the fruiting pattern of the olive tree complicates the geographical separation of oil samples and the selection of significant chemical compounds. In this way the inclusion of the harvesting year improved the classification of samples, but increased the dimensionality of the data. Discriminant analysis showed that the geographical prediction at the level of three regions is very high (87%) and becomes (74%) when we pass to the thinner level of six sites (Chania, Sitia, and Heraklion in Crete; Lakonia and Messinia in Peloponnesus; Zakynthos). The use of classification and binary trees made possible the construction of a geographical prediction algorithm for unknown samples in a self-improvement fashion, which can be readily extended to other varieties and areas.

  12. [31P-NMR analysis of high energy phosphorous compounds (ATP and phosphocreatine) in the living rat brain--effects of halothane anesthesia and a hypoxic condition].

    PubMed

    Yuasa, T; Miyatake, T; Kuwabara, T; Umeda, M; Eguchi, K

    1983-11-01

    31phosphorus nuclear magnetic resonance (31P-NMR) measurements have provided new and valuable insights for studying the metabolism of living systems. The aim of this paper is to introduce a technique of application of 31P-NMR measurements using a surface coil method, and to discuss the effects of halothane anesthesia and hypoxic hypoxia on the energetic metabolism of intact rat brains. All measurements were made using a JEOL FX 270 spectrometer with a super conducting magnet of 54-mm bore diameter. The magnetic field intensity of this machine is 6.3 tesla, and the resonance frequency used for 31P was 109.14 MHz. We remodelled an ordinary probe to take a live rat, and the animals were made to inhale anesthetic halothane or mixture of oxygen and nitrogen at various concentrations controlled by a flow regulator. The best conditions for measurements with our surface coil method were determined in this study as follows: (1) 90 degrees pulse width and selectivity, Fig. 1 shows signal selectivity in depthwise direction changed with 90 degrees pulse width, which was set to 20 microseconds. (2) Sensitivity and resolution; To obtain a spectrum of 31P-NMR from a rat brain 500 accumulations of free induction decays were considered suitable for both time and space resolution. Fig. 2 shows variations of signal intensity with pulse repetition time, which was set to 2 sec. It took about 17 min for averaging to get a spectrogram. (3) Quantitative accuracy and qualification; As shown in Fig. 3, a linear relationship was found between the signal intensity of beta-phosphate of ATP and the concentration of ATP solutions, thus proving the quantitative accuracy of our systems.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6661335

  13. 31P NMR and Genetic Analysis Establish hinT as the only E. coli Purine Nucleoside Phosphoramidase and as Essential for Growth under High Salt Conditions

    PubMed Central

    Chou, Tsui-Fen; Bieganowski, Pawel; Shilinski, Kara; Cheng, Jilin; Brenner, Charles; Wagner, Carston R.

    2008-01-01

    Eukaryotic cells encode AMP-lysine hydrolases related to the rabbit histidine triad nucleotide-binding protein 1 (Hint1) sequence. Bacterial and archaeal cells have Hint homologs annotated in a variety of ways but the enzymes have not been characterized, nor have phenotypes been described due to loss of enzymatic activity. We developed a quantitative 31P NMR assay to determine whether Escherichia coli possesses an adenosine phosphoramidase activity. Indeed, soluble lysates prepared from wild-type laboratory Escherichia coli exhibited activity on the model substrate adenosine monophosphoramidate (AMP-NH2). The Escherichia coli Hint homolog, which had been comprehensively designated ycfF and is here named hinT, was cloned, over-expressed, purified and characterized with respect to purine nucleoside phosphoramidate substrates. Bacterial hinT was several times more active than mammalian Hint on three model substrates. In addition, bacterial and mammalian enzymes preferred guanosine versus adenosine phosphoramidates as substrates. Analysis of the lysates from a constructed hinT knockout strain of Escherichia coli demonstrated that all of the cellular purine nucleoside phosphoramidase activity is due to hinT. Physiological analysis of this mutant revealed that the loss of hinT enzymatic activity results in failure to grow in media containing 0.75 KCl, 0.9 M NaCl, 0.5 M NaOAc and 10 mM MnCl2. Thus, bacteria may possess nucleotidylylated phosphoramidate substrates that must be hydrolyzed to support growth under certain high salt conditions. PMID:15703176

  14. Analysis of brain metabolism changes induced by acute potassium cyanide intoxication by 31P NMR in vivo using chronically implanted surface coils.

    PubMed

    Decorps, M; Lebas, J F; Leviel, J L; Confort, S; Remy, C; Benabid, A L

    1984-03-12

    Chronic implantation of surface coils on the skull has been developed to record 31P NMR spectra of the brain in unanesthetized rats. Intraperitoneal sublethal potassium cyanide doses induce strong and reversible changes in high-energy phosphate compounds in the brain, similar in part to those induced by ischemia. These effects are dose-dependent as far as phosphocreatine, inorganic orthophosphates and pH are concerned; ATP does not seem to be altered by KCN doses ranging from 3 to 5 mg/kg but starts decreasing at a dose of 6 mg/kg. The fraction of Mg2+ complexed ATP which could be estimated as about 90% was not affected by KCN intoxication. For high doses (6 mg/kg) a new peak, appearing on the upfield side of the inorganic phosphate peak, may correspond to an acidic compartment, the significance of which is discussed.

  15. Analysis of brain metabolism changes induced by acute potassium cyanide intoxication by 31P NMR in vivo using chronically implanted surface coils.

    PubMed

    Decorps, M; Lebas, J F; Leviel, J L; Confort, S; Remy, C; Benabid, A L

    1984-03-12

    Chronic implantation of surface coils on the skull has been developed to record 31P NMR spectra of the brain in unanesthetized rats. Intraperitoneal sublethal potassium cyanide doses induce strong and reversible changes in high-energy phosphate compounds in the brain, similar in part to those induced by ischemia. These effects are dose-dependent as far as phosphocreatine, inorganic orthophosphates and pH are concerned; ATP does not seem to be altered by KCN doses ranging from 3 to 5 mg/kg but starts decreasing at a dose of 6 mg/kg. The fraction of Mg2+ complexed ATP which could be estimated as about 90% was not affected by KCN intoxication. For high doses (6 mg/kg) a new peak, appearing on the upfield side of the inorganic phosphate peak, may correspond to an acidic compartment, the significance of which is discussed. PMID:6705916

  16. Tendencies of 31P chemical shifts changes in NMR spectra of nucleotide derivatives.

    PubMed

    Lebedev, A V; Rezvukhin, A I

    1984-07-25

    31P NMR chemical shifts of the selected mono- and oligonucleotide derivatives, including the compounds with P-N, P-C, P-S bonds and phosphite nucleotide analogues have been presented. The influence of substituents upon 31P chemical shifts has been discussed. The concrete examples of 31P chemical shifts data application in the field of nucleotide chemistry have been considered.

  17. Method development in quantitative NMR towards metrologically traceable organic certified reference materials used as (31)P qNMR standards.

    PubMed

    Weber, Michael; Hellriegel, Christine; Rueck, Alexander; Wuethrich, Juerg; Jenks, Peter; Obkircher, Markus

    2015-04-01

    Quantitative nuclear magnetic resonance (qNMR) spectroscopy is employed by an increasing number of analytical and industrial laboratories for the assignment of content and quantitative determination of impurities. Within the last few years, it was demonstrated that (1)H qNMR can be performed with high accuracy leading to measurement uncertainties below 1 % relative. It was even demonstrated that the combination of (1)H qNMR with metrological weighing can lead to measurement uncertainties below 0.1 % when highly pure substances are used. Although qNMR reference standards are already available as certified reference materials (CRM) providing traceability on the basis of (1)H qNMR experiments, there is an increasing demand for purity assays on phosphorylated organic compounds and metabolites requiring CRM for quantification by (31)P qNMR. Unfortunately, the number of available primary phosphorus standards is limited to a few inorganic CRM which only can be used for the analysis of water-soluble analytes but fail when organic solvents must be employed. This paper presents the concept of value assignment by (31)P qNMR measurements for the development of CRM and describes different approaches to establish traceability to primary Standard Reference Material from the National Institute of Standards and Technology (NIST SRM). Phosphonoacetic acid is analyzed as a water-soluble CRM candidate, whereas triphenyl phosphate is a good candidate for the use as qNMR reference material in organic solvents. These substances contain both nuclei, (1)H and (31)P, and the concept is to show that it is possible to indirectly quantify a potential phosphorus standard via its protons using (1)H qNMR. The same standard with its assigned purity can then be used for the quantification of an analyte via its phosphorus using (31)P qNMR. For the validation of the concept, triphenyl phosphate and phosphonoacetic acid have been used as (31)P qNMR standards to determine the purity of the analyte

  18. Method development in quantitative NMR towards metrologically traceable organic certified reference materials used as (31)P qNMR standards.

    PubMed

    Weber, Michael; Hellriegel, Christine; Rueck, Alexander; Wuethrich, Juerg; Jenks, Peter; Obkircher, Markus

    2015-04-01

    Quantitative nuclear magnetic resonance (qNMR) spectroscopy is employed by an increasing number of analytical and industrial laboratories for the assignment of content and quantitative determination of impurities. Within the last few years, it was demonstrated that (1)H qNMR can be performed with high accuracy leading to measurement uncertainties below 1 % relative. It was even demonstrated that the combination of (1)H qNMR with metrological weighing can lead to measurement uncertainties below 0.1 % when highly pure substances are used. Although qNMR reference standards are already available as certified reference materials (CRM) providing traceability on the basis of (1)H qNMR experiments, there is an increasing demand for purity assays on phosphorylated organic compounds and metabolites requiring CRM for quantification by (31)P qNMR. Unfortunately, the number of available primary phosphorus standards is limited to a few inorganic CRM which only can be used for the analysis of water-soluble analytes but fail when organic solvents must be employed. This paper presents the concept of value assignment by (31)P qNMR measurements for the development of CRM and describes different approaches to establish traceability to primary Standard Reference Material from the National Institute of Standards and Technology (NIST SRM). Phosphonoacetic acid is analyzed as a water-soluble CRM candidate, whereas triphenyl phosphate is a good candidate for the use as qNMR reference material in organic solvents. These substances contain both nuclei, (1)H and (31)P, and the concept is to show that it is possible to indirectly quantify a potential phosphorus standard via its protons using (1)H qNMR. The same standard with its assigned purity can then be used for the quantification of an analyte via its phosphorus using (31)P qNMR. For the validation of the concept, triphenyl phosphate and phosphonoacetic acid have been used as (31)P qNMR standards to determine the purity of the analyte

  19. [sup 31]P NMR study of immobilized artificial membrane surfaces. Structure and dynamics of immobilized phospholipids

    SciTech Connect

    Qiu, X.; Pidgeon, C. )

    1993-11-25

    Chromatography surfaces were prepared by immobilizing a single-chain ether phospholipid at approximately a monolayer density on silica particles. The chromatography particles are denoted as [sup ether]IAM.PC[sup C10/C3], and they are stable to all solvents. The structure and dynamics of the interphase created by immobilizing phospholipids on silica particles were studied by [sup 31]P NMR methods. [sup ether]IAM.PC[sup C10/C3] spontaneously wets when suspended in both aqueous and organic solvents, and [sup 31]P NMR spectra were obtained in water, methanol, chloroform, acetonitrile, and acetone. [sup 31]P NMR spectra were subjected to line-shape analysis. From line-shape analysis, the correlation times for rapid internal motion ([tau]-PLL) and wobbling ([tau]-PRP) of the phospholipid headgroup were calculated for each solvent. Immobilized phospholipid headgroups comprising the IAM interfacial region undergo rapid reorientation similar to the case of the phospholipids forming liposome membranes with [tau]-PLL approximately 1 ns. Phospholipids in liposome membranes exhibit slower wobbling motion ([tau]-PRP approximately 1 ms) in the plane of the membrane. However, the immobilized phospholipids on [sup ether]IAM.PC[sup C10/C3] surfaces wobble with correlation times [tau]-PRP that depend on the solvent bathing the [sup ether]IAM.PC[sup C10/C3] surface. 41 refs., 9 figs., 2 tabs.

  20. Quantitative 31P NMR for Simultaneous Trace Analysis of Organophosphorus Pesticides in Aqueous Media Using the Stir Bar Sorptive Extraction Method

    NASA Astrophysics Data System (ADS)

    Ansari, S.; Talebpour, Z.; Molaabasi, F.; Bijanzadeh, H. R.; Khazaeli, S.

    2016-09-01

    The analysis of pesticides in water samples is of primary concern for quality control laboratories due to the toxicity of these compounds and their associated public health risk. A novel analytical method based on stir bar sorptive extraction (SBSE), followed by 31P quantitative nuclear magnetic resonance (31P QNMR), has been developed for simultaneously monitoring and determining four organophosphorus pesticides (OPPs) in aqueous media. The effects of factors on the extraction efficiency of OPPs were investigated using a Draper-Lin small composite design. An optimal sample volume of 4.2 mL, extraction time of 96 min, extraction temperature of 42°C, and desorption time of 11 min were obtained. The results showed reasonable linearity ranges for all pesticides with correlation coefficients greater than 0.9920. The limit of quantification (LOQ) ranged from 0.1 to 2.60 mg/L, and the recoveries of spiked river water samples were from 82 to 94% with relative standard deviation (RSD) values less than 4%. The results show that this method is simple, selective, rapid, and can be applied to other sample matrices.

  1. Compartmentation of Nucleotides in Corn Root Tips Studied by 31P-NMR and HPLC 1

    PubMed Central

    Hooks, Mark A.; Clark, Robert A.; Nieman, Richard H.; Roberts, Justin K. M.

    1989-01-01

    Corn (Zea mays L.) root tips were subjected to different conditions so that nucleotide levels varied over a wide range. Levels of nucleotides in corn root tips were measured using 31P nuclear magnetic resonance (NMR) spectroscopy and high performance liquid chromatography. Results indicate: (a) Similar amounts of NTP and sugar nucleotides were observed by in vivo NMR and in extracts. In contrast, a significant amount of NDP observed in root tip extracts was not detected by in vivo NMR. Thus, for a given sample, [NTP]/[NDP] ratios determined in vivo by 31P-NMR are always higher than ratios observed in extracts, deviating by ∼4-fold at the highest ratios. The NMR-invisible pool of NDP appeared quite metabolically inert, barely changing in size as total cell NDP changed. We conclude that NDP in corn root tips is compartmented with respect to NMR visibility, and that it is the NMR-visible pool which responds dynamically to metabolic state. The NMR-invisible NDP could either be immobilized (and so have broad, undetectable NMR signals), or be complexed with species that cause the chemical shift of NDP to change (so it does not contribute to the NMR signal of free NDP), or both. (b) 31P-NMR cannot distinguish between bases (A, U, C, and G) of nucleotides. HPLC analysis of root tip extracts showed that the relative amount of each base in the NTP and NDP pools was quite constant in the different samples. (c) In extracts, for each of the nonadenylate nucleotides, [NTP]/[NDP] was linearly proportional to [ATP]/[ADP], indicating near equilibrium in the nucleoside diphosphokinase (NDPK) reaction. However, the apparent equilibrium constants for the phosphorylation of GDP and UDP by ATP were significantly lower than 1, the true equilibrium constant for the NDPK reaction. Thus, for a given sample, [ATP]/[ADP] ∼ [CTP]/[CDP] > [UTP]/[UDP] > [GTP]/[GDP]. This result suggests that the different NDPs in corn root tips do not have equal access to NDPK. PMID:16666649

  2. Metabolic engineering applications of in vivo sup 31 P and sup 13 C NMR studies of Saccharomyces cerevisiae

    SciTech Connect

    Shanks, J.V.

    1989-01-01

    With intent to quantify NMR measurements as much as possible, analysis techniques of the in vivo {sup 31}P NMR spectrum are developed. A systematic procedure is formulated for estimating the relative intracellular concentrations of the sugar phosphates in S. cerevisiae from the {sup 31}P NMR spectrum. In addition, in vivo correlation of inorganic phosphate chemical shift with the chemical shifts of 3-phosphoglycerate, {beta}-fructose 1,6-diphosphate, fructose 6-phosphate, and glucose 6-phosphate are determined. Also, a method was developed for elucidation of the cytoplasmic and vacuolar components of inorganic phosphate in the {sup 31}P NMR spectrum of S. cerevisiae. An in vivo correlation relating the inorganic phosphate chemical shift of the vacuole with the chemical shift of the resonance for pyrophosphate and the terminal phosphate of polyphosphate (PP{sub 1}) is established. Transient measurements provided by {sup 31}P NMR are applied to reg1 mutant and standard strains. {sup 31}P and {sup 13}C NMR measurements are used to analyze the performance of recombinant strains in which the glucose phosphorylation step had been altered.

  3. Tendencies of 31P chemical shifts changes in NMR spectra of nucleotide derivatives.

    PubMed

    Lebedev, A V; Rezvukhin, A I

    1984-07-25

    31P NMR chemical shifts of the selected mono- and oligonucleotide derivatives, including the compounds with P-N, P-C, P-S bonds and phosphite nucleotide analogues have been presented. The influence of substituents upon 31P chemical shifts has been discussed. The concrete examples of 31P chemical shifts data application in the field of nucleotide chemistry have been considered. PMID:6087290

  4. In vivo dephosphorylation of WR-2721 monitored by 31P NMR spectroscopy

    SciTech Connect

    Knizner, S.A.; Jacobs, A.J.; Lyon, R.C.; Swenberg, C.E.

    1986-01-01

    The in vivo dephosphorylation of the radioprotective agent S-2-(3-(aminopropylamino))ethylphosphorothioic acid (WR-2721) in male CD2F1 mice was measured by 31P NMR spectroscopy after i.p. injection. The disappearance of the WR-2721 phosphate NMR signal with time was concurrent with an increase and splitting of the inorganic phosphate NMR signal. The more acidic inorganic phosphate resonance is shown to be attributed to phosphate (inorganic phosphate) in the urine. Using regression first-order kinetic analysis of data, after i.p. injection of 600 mg/kg, the half-life of WR-2721 was determined to be 40.9 +/- 5.9 (S.D.) min (n = 10).

  5. Exploring new Routes for Identifying Phosphorus Species in Terrestrial and Aquatic Ecosystems with 31P NMR

    NASA Astrophysics Data System (ADS)

    Vestergren, Johan; Persson, Per; Sundman, Annelie; Ilstedt, Ulrik; Giesler, Reiner; Schleucher, Jürgen; Gröbner, Gerhard

    2014-05-01

    develop a new method to retrieve and characterize P components in water. By utilizing passive sampling with ion-exchange resin and subsequent analysis with solid state 31P MAS NMR we could identify various P-species extracted from the aquatic systems. By using this approach we can also study the dynamics of the absorption process at the resin as a function of P-species and temperature. This even enabled us to extract the fraction of bound versus free P as a function of temperature for different model P-components (manuscript in preparation). REFERENCES: Gilbert N. Nature 461 716-718 (2009) Vincent AG. et al., Biogeochemistry, 10.1007/s10533-011-9612-0 (2011). Vestergren J et al., Environ. Sci. Technol, 46, 3950-3956, (2012). Vincent AG et al., Plant Soil, 367, 149-162, (2013). Laudon H., et al., Water Resour. Res., 49, 7154-7158, (2013).

  6. Detoxification of organophosphorus pesticides and nerve agents through RSDL: efficacy evaluation by (31)P NMR spectroscopy.

    PubMed

    Elsinghorst, Paul W; Worek, Franz; Koller, Marianne

    2015-03-01

    Intoxication by organophosphorus compounds, especially by pesticides, poses a considerable risk to the affected individual. Countermeasures involve both medical intervention by means of antidotes as well as external decontamination to reduce the risk of dermal absorption. One of the few decontamination options available is Reactive Skin Decontamination Lotion (RSDL), which was originally developed for military use. Here, we present a (31)P NMR spectroscopy based methodology to evaluate the detoxification efficacy of RSDL with respect to a series of organophosphorus pesticides and nerve agents. Kinetic analysis of the obtained NMR data provided degradation half-lives proving that RSDL is also reasonably effective against organophosphorus pesticides. Unexpected observations of different RSDL degradation patterns are presented in view of its reported oximate-catalyzed mechanism of action.

  7. Detoxification of organophosphorus pesticides and nerve agents through RSDL: efficacy evaluation by (31)P NMR spectroscopy.

    PubMed

    Elsinghorst, Paul W; Worek, Franz; Koller, Marianne

    2015-03-01

    Intoxication by organophosphorus compounds, especially by pesticides, poses a considerable risk to the affected individual. Countermeasures involve both medical intervention by means of antidotes as well as external decontamination to reduce the risk of dermal absorption. One of the few decontamination options available is Reactive Skin Decontamination Lotion (RSDL), which was originally developed for military use. Here, we present a (31)P NMR spectroscopy based methodology to evaluate the detoxification efficacy of RSDL with respect to a series of organophosphorus pesticides and nerve agents. Kinetic analysis of the obtained NMR data provided degradation half-lives proving that RSDL is also reasonably effective against organophosphorus pesticides. Unexpected observations of different RSDL degradation patterns are presented in view of its reported oximate-catalyzed mechanism of action. PMID:25597861

  8. Phospholipid composition of plasma and erythrocyte membranes in animal species by 31P NMR.

    PubMed

    Ferlazzo, Alida Maria; Bruschetta, Giuseppe; Di Pietro, Patrizia; Medica, Pietro; Notti, Anna; Rotondo, Enrico

    2011-12-01

    The aim of this study was to provide basal values of phospholipid (PL) composition in different animal species by 31P NMR analysis using detergents. This fast and accurate method allowed a quantitative analysis of PLs without any previous separation. Plasma and erythrocyte membrane PLs were investigated in mammals (pig, cow, horse). Moreover, for the first time, the composition of plasma PLs in avian (chicken and ostrich) was performed by 31P NMR. Significant qualitative and quantitative interspecies differences in plasma PL levels were found. Phosphatidilcholine (PC) and sphingomyelin (SPH) levels were significantly higher (P < 0.001) in chicken plasma than all the other species tested. In erythrocytes, cow PC and phosphatidylcholine diarachidoyl were significantly lower (P < 0.001) than for pigs and horses, whereas pig PC presented intermediate values among cows and horses. Inorganic phosphate and 2,3-diphosphoglycerate levels were also significantly different between the species under investigation. The [SPH/total PLs] molar ratios in erythrocytes confirmed interspecies differences in phospholipid composition while the PC/SPH molar ratios could be related to a distinct erythrocyte flexibility and aggregability. Diet and nutrition may contribute primarily to the interspecies differences in plasma PL amounts detected. Significant differences between chicken plasma PC and SPH levels and those of the other animal species could be ascribed to a fat metabolism specific to egg production.

  9. Chemical Characterization and Water Content Determination of Bio-Oils Obtained from Various Biomass Species using 31P NMR Spectroscopy

    SciTech Connect

    David, K.; Ben, H.; Muzzy, J.; Feik, C.; Iisa, K.; Ragauskas, A.

    2012-03-01

    Pyrolysis is a promising approach to utilize biomass for biofuels. One of the key challenges for this conversion is how to analyze complicated components in the pyrolysis oils. Water contents of pyrolysis oils are normally analyzed by Karl Fischer titration. The use of 2-chloro-4,4,5,5,-tetramethyl-1,3,2-dioxaphospholane followed by {sup 31}P NMR analysis has been used to quantitatively analyze the structure of hydroxyl groups in lignin and whole biomass. Results: {sup 31}P NMR analysis of pyrolysis oils is a novel technique to simultaneously characterize components and analyze water contents in pyrolysis oils produced from various biomasses. The water contents of various pyrolysis oils range from 16 to 40 wt%. The pyrolysis oils obtained from Loblolly pine had higher guaiacyl content, while that from oak had a higher syringyl content. Conclusion: The comparison with Karl Fischer titration shows that {sup 31}P NMR could also reliably be used to measure the water content of pyrolysis oils. Simultaneously with analysis of water content, quantitative characterization of hydroxyl groups, including aliphatic, C-5 substituted/syringyl, guaiacyl, p-hydroxyl phenyl and carboxylic hydroxyl groups, could also be provided by {sup 31}P NMR analysis.

  10. Membrane interactions in small fast-tumbling bicelles as studied by 31P NMR.

    PubMed

    Bodor, Andrea; Kövér, Katalin E; Mäler, Lena

    2015-03-01

    Small fast-tumbling bicelles are ideal for studies of membrane interactions at molecular level; they allow analysis of lipid properties using solution-state NMR. In the present study we used 31P NMR relaxation to obtain detailed information on lipid head-group dynamics. We explored the effect of two topologically different membrane-interacting peptides on bicelles containing either dimyristoylphosphocholine (DMPC), or a mixture of DMPC and dimyristoylphosphoglycerol (DMPG), and dihexanoylphosphocholine (DHPC). KALP21 is a model transmembrane peptide, designed to span a DMPC bilayer and dynorphin B is a membrane surface active neuropeptide. KALP21 causes significant increase in bicelle size, as evidenced by both dynamic light scattering and 31P T2 relaxation measurements. The effect of dynorphin B on bicelle size is more modest, although significant effects on T2 relaxation are observed at higher temperatures. A comparison of 31P T1 values for the lipids with and without the peptides showed that dynorphin B has a greater effect on lipid head-group dynamics than KALP21, especially at elevated temperatures. From the field-dependence of T1 relaxation data, a correlation time describing the overall lipid motion was derived. Results indicate that the positively charged dynorphin B decreases the mobility of the lipid molecules--in particular for the negatively charged DMPG--while KALP21 has a more modest influence. Our results demonstrate that while a transmembrane peptide has severe effects on overall bilayer properties, the surface bound peptide has a more dramatic effect in reducing lipid head-group mobility. These observations may be of general importance for understanding peptide-membrane interactions. PMID:25497765

  11. Solid State FT-IR and (31)P NMR Spectral Features of Phosphate Compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Solid-state spectroscopic techniques, including Fourier transform infrared (FT-IR) and solid-state 31P magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopies, are powerful tools for evaluating metal speciation and transformation mechanisms of P compounds in the environment. Studie...

  12. Characterization of active phosphorus surface sites at synthetic carbonate-free fluorapatite using single-pulse 1H, 31P, and 31P CP MAS NMR.

    PubMed

    Jarlbring, Mathias; Sandström, Dan E; Antzutkin, Oleg N; Forsling, Willis

    2006-05-01

    The chemically active phosphorus surface sites defined as PO(x), PO(x)H, and PO(x)H2, where x = 1, 2, or 3, and the bulk phosphorus groups of PO4(3-) at synthetic carbonate-free fluorapatite (Ca5(PO4)3F) have been studied by means of single-pulse 1H,31P, and 31P CP MAS NMR. The changes in composition and relative amounts of each surface species are evaluated as a function of pH. By combining spectra from single-pulse 1H and 31P MAS NMR and data from 31P CP MAS NMR experiments at varying contact times in the range 0.2-3.0 ms, it has been possible to distinguish between resonance lines in the NMR spectra originating from active surface sites and bulk phosphorus groups and also to assign the peaks in the NMR spectra to the specific phosphorus species. In the 31P CP MAS NMR experiments, the spinning frequency was set to 4.2 kHz; in the single-pulse 1H MAS NMR experiments, the spinning frequency was 10 kHz. The 31P CP MAS NMR spectrum of fluorapatite at pH 5.9 showed one dominating resonance line at 2.9 ppm assigned to originate from PO4(3-) groups and two weaker shoulder peaks at 5.4 and 0.8 ppm which were assigned to the unprotonated PO(x) (PO, PO2-, and PO3(2-)) and protonated PO(x)H (PO2H and PO3H-) surface sites. At pH 12.7, the intensity of the peak representing unprotonated PO(x) surface sites has increased 1.7% relative to the bulk peak, while the intensity of the peaks of the protonated species PO(x)H have decreased 1.4% relative to the bulk peak. At pH 3.5, a resonance peak at -4.5 ppm has appeared in the 31P CP MAS NMR spectrum assigned to the surface species PO(x)H2 (PO3H2). The results from the 1H MAS and 31P CP MAS NMR measurements indicated that H+, OH-, and physisorbed H2O at the surface were released during the drying process at 200 degrees C.

  13. Acid properties of solid acid catalysts characterized by solid-state 31P NMR of adsorbed phosphorous probe molecules.

    PubMed

    Zheng, Anmin; Huang, Shing-Jong; Liu, Shang-Bin; Deng, Feng

    2011-09-01

    A brief review is presented on acidity characterization of solid acid catalysts by means of solid-state phosphor-31 magic-angle-spinning nuclear magnetic resonance ((31)P MAS NMR) spectroscopy using phosphor-containing molecules as probes. It is emphasized that such a simple approach using (31)P MAS NMR of adsorbed phosphorous probe molecules, namely trimethylphosphine (TMP) and trialkylphosphine oxides (R(3)PO), represents a unique technique in providing detailed qualitative and quantitative features, viz. type, strength, distribution, and concentration of acid sites in solid acid catalysts. In particular, it will be shown that when applied with a proper choice of probe molecules with varied sizes and results obtained from elemental analysis, the amounts and locations (intracrystalline vs. extracrystalline) of different types (Brønsted vs. Lewis) of acid sites may be determined. In addition, by incorporating the NMR results with that obtained from theoretical density functional theory (DFT) calculations, correlations between the (31)P chemical shifts (δ(31)P) and acidic strengths of Brønsted and Lewis acid sites may also be derived, facilitating a suitable acidity scale for solid acid catalysts.

  14. Structure and motion of phospholipids in human plasma lipoproteins. A sup 31 P NMR study

    SciTech Connect

    Fenske, D.B.; Chana, R.S.; Parmar, Y.I.; Treleaven, W.D.; Cushley, R.J. )

    1990-04-24

    The structure and motion of phospholipids in human plasma lipoproteins have been studied by using {sup 31}P NMR. Lateral diffusion coefficients, D{sub T}, obtained from the viscosity dependence of the {sup 31}P NMR line widths, were obtained for very low density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoproteins (HDL{sub 2}, HDL{sub 3}), and egg PC/TO microemulsions at 25{degree}C, for VLDL at 40{degree}C, and for LDL at 45{degree}C. In order to prove the orientation and/or order of the phospholipid head-group, estimates of the residual chemical shift anistropy, {Delta}{sigma}, have been obtained for all the lipoproteins and the microemulsions from the viscosity and field dependence for the {sup 31}P NMR line widths. These results suggest differences in the orientation and/or ordering of the head-group in the HDLs. The dynamic behavior of the phosphate moiety in LDL and HDL{sub 3} has been obtained from the temperature dependence of the {sup 31}P spin-lattice relaxation rates. Values of the correlation time for phosphate group reorientation and the activation energy for the motion are nearly identical in LDL and HDL{sub 3} and are similar to values obtained for phospholipid bilayers. This argues against long-lived protein-lipid interactions being the source of either the slow diffusion in LDL or the altered head-group orientation in the HDLs.

  15. Rapid assignment of solution 31P NMR spectra of large proteins by solid-state spectroscopy.

    PubMed

    Iuga, Adriana; Spoerner, Michael; Ader, Christian; Brunner, Eike; Kalbitzer, Hans Robert

    2006-07-21

    The application of the (31)P NMR spectroscopy to large proteins or protein complexes in solution is hampered by a relatively low intrinsic sensitivity coupled with large line widths. Therefore, the assignment of the phosphorus signals by two-dimensional NMR methods in solution is often extremely time consuming. In contrast, the quality of solid-state NMR spectra is not dependent on the molecular mass and the solubility of the protein. For the complex of Ras with the GTP-analogue GppCH(2)p we show solid-state (31)P NMR methods to be more sensitive by almost one order of magnitude than liquid-state NMR. Thus, solid-state NMR seems to be the method of choice for obtaining the resonance assignment of the phosphorus signals of protein complexes in solution. Experiments on Ras.GDP complexes show that the microcrystalline sample can be substituted by a precipitate of the sample and that unexpectedly the two structural states observed earlier in solution are present in crystals as well.

  16. CD and 31P NMR studies of tachykinin and MSH neuropeptides in SDS and DPC micelles

    NASA Astrophysics Data System (ADS)

    Schneider, Sydney C.; Brown, Taylor C.; Gonzalez, Javier D.; Levonyak, Nicholas S.; Rush, Lydia A.; Cremeens, Matthew E.

    2016-02-01

    Secondary structural characteristics of substance P (SP), neurokinin A (NKA), neurokinin B (NKB), α-melanocyte stimulating hormone peptide (α-MSH), γ1-MSH, γ2-MSH, and melittin were evaluated with circular dichroism in phosphite buffer, DPC micelles, and SDS micelles. CD spectral properties of γ1-MSH and γ2-MSH as well as 31P NMR of DPC micelles with all the peptides are reported for the first time. Although, a trend in the neuropeptide/micelle CD data appears to show increased α-helix content for the tachykinin peptides (SP, NKA, NKB) and increased β-sheet content for the MSH peptides (α-MSH, γ1-MSH, γ2-MSH) with increasing peptide charge, the lack of perturbed 31P NMR signals for all neuropeptides could suggest that the reported antimicrobial activity of SP and α-MSH might not be related to a membrane disruption mode of action.

  17. 31P NMR investigations on the ferromagnetic quantum critical system YbNi4P2

    NASA Astrophysics Data System (ADS)

    Sarkar, R.; Khuntia, P.; Krellner, C.; Geibel, C.; Steglich, F.; Baenitz, M.

    2012-04-01

    We studied the heavy-fermion system YbNi4P2, which presents strong ferromagnetic correlations, using the local 31P NMR probe over a wide field (0.2-8.6 T) and temperature (1.8-200 K) range. The 31P NMR Knight shift provides the static spin susceptibility which tracks the bulk susceptibility whereas the spin-lattice relaxation rate 31(1/T1) provides information about the fluctuations of the Yb 4f moment. The Korringa law is valid over a wide range of temperature and field. The Korringa product 31(1/T1TK2S0)≪1 gives evidence for the presence of strong ferromagnetic correlations. A 31(1/T1T)˜T-3/4 behavior was found over two decades in temperature.

  18. Improvement of (31)P NMR spectral resolution by 8-hydroxyquinoline precipitation of paramagnetic Fe and Mn in environmental samples.

    PubMed

    Ding, Shiming; Xu, Di; Li, Bin; Fan, Chengxin; Zhang, Chaosheng

    2010-04-01

    Solution (31)P nuclear magnetic resonance (NMR) spectroscopy is currently the main method for the characterization of phosphorus (P) forms in environment samples. However, identification and quantification of P compounds may be hampered by poor resolution of spectra caused by paramagnetic Fe and Mn. In this study, a novel technique was developed to improve spectral resolution by removing paramagnetic Fe and Mn from alkaline extracts via 8-hydroxyquinoline (8-HOQ) precipitation. Batch experiments showed that both Fe and Mn were effectively removed by the precipitation at pH 9.0, with the removal efficiencies of 83-91% for Fe and 67-78% for Mn from the extracts of five different environmental samples, while little effect was found on concentration of total P. The (31)P NMR analysis of a model P solution showed that addition of 8-HOQ and its precipitation with metal ions did not alter P forms. Further analyses of the five extracts with (31)P NMR spectroscopy demonstrated that the 8-HOQ precipitation was an ideal method compared with the present postextraction techniques, such as bicarbonate dithionate (BD), EDTA and Chelex-100 treatments, by improving spectral resolution to a large extent with no detrimental effects on P forms. PMID:20201571

  19. Solid state {sup 31}P/{sup 27}Al and {sup 31}P/{sup 23}Na MAS NMR dipolar dephasing investigations of connectivity in sodium aluminophosphate glasses

    SciTech Connect

    LANG,DAVID P.; ALAM,TODD M.; BENCOE,DENISE N.

    2000-05-01

    Solid state {sup 31}P/{sup 27}Al and {sup 31}P/{sup 23}Na MAS NMR dipolar dephasing experiments have been used to investigate the spatial distribution of aluminum and sodium cations with respect to the phosphate backbone for a series of sodium aluminophosphate glasses, xAl{sub 2}O{sub 3}{center_dot}50Na{sub 2}O{center_dot}(50{minus}x)P{sub 2}O{sub 5} (0{le} x {le} 17.5). From the {sup 31}P/{sup 27}Al and {sup 31}P/{sup 23}Na connectivity data gathered, information about the medium range order in these glasses is obtained. The expanded connectivity data allows for better identification and interpretation of the new resonances observed in the {sup 31}P MAS NMR spectra with the addition of alumina. The results of the dipolar dephasing experiments show that the sodium-phosphate distribution remains relatively unchanged for the glass series, and that the addition of aluminum occurs primarily through the depolymerization of the phosphate tetrahedral backbone.

  20. In vivo 31P-NMR spectroscopy of right ventricle in pigs.

    PubMed

    Schwartz, G G; Steinman, S K; Weiner, M W; Matson, G B

    1992-06-01

    The energy metabolism of the right ventricle (RV) in vivo has been largely unexplored. The goal of this study was to develop and implement techniques for in vivo 31P nuclear magnetic resonance (NMR) spectroscopy of the RV free wall. A two-turn, crossover-design elliptical surface coil was constructed to provide high sensitivity across the thin RV wall but minimal sensitivity in the blood-filled RV cavity. In 36 open-chest, anesthetized pigs, 31P spectroscopy of the RV free wall was performed with this coil at a field strength of 2 Tesla. Spectra were obtained from 800 acquisitions in 24 min with an average signal-to-noise ratio of 13.2 for phosphocreatine (PCr). The PCr-to-ATP (PCr/ATP) ratio of porcine RV was 1.42 +/- 0.05 (mean +/- SE), uncorrected for saturation at a repetition time of 1.8 s. With the use of literature values of the time constant of longitudinal relaxation (T1) to correct for partial saturation, the RV PCr/ATP was estimated to lie between 1.7 and 2.3. Decreased RV PCr/ATP was observed during RV ischemia and pressure overload. Thus in vivo 31P spectroscopy of the RV is readily accomplished with an appropriate surface coil and can provide new information about RV energy metabolism. PMID:1621852

  1. On the noninvasive measurement of intracellular free magnesium by 31P NMR spectroscopy.

    PubMed

    Gupta, R K; Gupta, P; Yushok, W D; Rose, Z B

    1983-01-01

    We previously introduced a noninvasive measurement of the concentration of free Mg2+ in intact cells and tissues using 31P NMR. To resolve a controversy in the literature concerning the affinity of Mg2+ for ATP used in our procedure, the apparent dissociation constant of MgATP under simulated intracellular conditions has been determined by three independent magnetic resonance methods, including a newly developed combination procedure for determining this value at intracellular ATP levels. The new combination method, which utilizes 31P NMR to determine the degree of Mg2+ chelation of ATP and the dye antipyrylazo III for optical determination of free Mg2+, yielded a value of (50 +/- 10) microM for this apparent dissociation constant at pH 7.2 in the presence of 0.15 M K+ and 25 degrees C. We further show that hydroxyquinolines are not satisfactory indicators for optical determination of the Mg2+-nucleotide dissociation constant. From our determinations a low value of free Mg2+ (less than 1 mM) is established for all of the tissues studied, including perfused heart muscle, contrary to a recent report in the literature. Saturating human erythrocytes with Mg2+ results in an alpha- and beta-phosphorus resonance separation for intracellular ATP that is indistinguishable from that observed in a noncellular MgATP control under similar conditions, showing that MgATP resonances in this cell are unaffected by the cellular environment.

  2. Synthesis of prostanoids; enantiomeric purity of alcohols by a /sup 31/P NMR technique

    SciTech Connect

    Penning, T.D.

    1985-01-01

    The enone, 2,2-diemthyl-3a..beta.., 6a..beta..-dihydro-4H-cyclopenta-1,3-dioxol-4-one, has been synthesized in six steps from cyclopentadiene, resolved using sulfoximine chemistry, and converted into (-)-prostaglandin E/sub 2/ methyl ester in three steps. Introduction of the optically pure omega side-chain using a conjugate addition of a stabilized organocopper reagent, followed by direct alkylation of the enolate with the ..cap alpha.. side-chain allylic iodide in the presence of hexamethylphosphoramide, afforded a trans, vicinally disubstituted cyclopentanone. Deprotection of the C-15 alcohol, followed by aluminum amalgam reduction of the C-10/oxygen bond, provided (-)-PGE/sub 2/ methyl ester in 47% overall yield from the enone. In an extension of previously described work, 2-chloro-3,4-dimethyl-5-phenyl-1,3,2-oxazaphospholidine 2-sulfide, prepared from l-ephedrine and thiophosphoryl chloride, was used to determine the enantiomeric excess of chiral alcohols in conjunction with /sup 31/P NMR. Chiral primary and secondary alcohols added quantitatively to the phospholidine to give diastereomers which could be analyzed by /sup 31/P NMR and HPLC. A number of other phosphorus heterocycles were also explored as potential chiral derivatizing reagents.

  3. Sediment depth attenuation of biogenic phosphorus compounds measured by 31P NMR.

    PubMed

    Ahlgren, Joakim; Tranvik, Lars; Gogoll, Adolf; Waldeback, Monica; Markides, Karin; Rydin, Emil

    2005-02-01

    Being a major cause of eutrophication and subsequent loss of water quality, the turnover of phosphorus (P) in lake sediments is in need of deeper understanding. A major part of the flux of P to eutrophic lake sediments is organically bound or of biogenic origin. This P is incorporated in a poorly described mixture of autochthonous and allochthonous sediment and forms the primary storage of P available for recycling to the water column, thus regulating lake trophic status. To identify and quantify biogenic sediment P and assess its lability, we analyzed sediment cores from Lake Erken, Sweden, using traditional P fractionation, and in parallel, NaOH extracts were analyzed using 31P NMR. The surface sediments contain orthophosphates (ortho-P) and pyrophosphates (pyro-P), as well as phosphate mono- and diesters. The first group of compounds to disappear with increased sediment depth is pyrophosphate, followed by a steady decline of the different ester compounds. Estimated half-life times of these compound groups are about 10 yr for pyrophosphate and 2 decades for mono- and diesters. Probably, these compounds will be mineralized to ortho-P and is thus potentially available for recycling to the water column, supporting further growth of phytoplankton. In conclusion, 31P NMR is a useful tool to asses the bioavailability of certain P compound groups, and the combination with traditional fractionation techniques makes quantification possible. PMID:15757351

  4. 31P NMR conformational studies of non-palindromic DNA duplexes related to HIV-1 enhancer

    NASA Astrophysics Data System (ADS)

    Tisne, C.; Simenel, C.; Hantz, E.; Delepierre, M.

    1998-02-01

    Assignment of all 31P resonances of 16 base-pair DNA duplexes, 5' d(CTGGGGACTTTCCAGG)3' 5' d(CCTGGAAAGTCCCCAG)3', related to the DNA kappaB site of the HIV-1 LTR together with a mutated sequence 5' d(CTGCTCACTTTCCAGG)3' 5' d(CCTGGAAAGTGAGCAG)3' was determined by 2D heteronuclear inverse NMR spectroscopy (HSQC-TOCSY and heteronuclear COSY). ^3JH{3'}-P coupling constants for most of the phosphates of the mutated oligomer were obtained using heteronuclear selective COSY. L'attribution des résonances 31P du fragment d'ADN de seize paires de base 5' d(CTGGGGACTTTCCAGG)3' 5' d(CCTGGAAAGTCCCCAG)3' (16N) correspondant au site kappaB du LTR du HIV-1 et de la séquence mutée 5' d(CTGCTCACTTTCCAGG)3' 5' d(CCTGGAAAGTGAGCAG)3' (16M) a été déterminée à l'aide de méthodes 2D hétéronucléaires à détection indirecte (HSQC-TOCSY et COSY hétéronucléaires). Les constantes de couplage ^3JH{3'}-P ont été mesurées pour la plupart des phosphates de 16 M à l'aide d'expérience COSY hétéronucléaires sélectives.

  5. Investigation of broad resonances in 31P NMR spectra of the human brain in vivo.

    PubMed

    McNamara, R; Arias-Mendoza, F; Brown, T R

    1994-08-01

    Broad resonances that lie underneath the familiar small molecule profile of in vivo 31P NMR spectra can make accurate spectral integration of these mobile phosphates difficult. The two major broad components are the phosphate contained in the hydroxyapatite in cranial bone and the phosphodiester moiety in partially mobile membrane phospholipids. They can be removed with post-acquisition processing but this results in distortion of lineshapes and intensities and interferes with accurate quantitation. We have employed an off-resonance saturation procedure to eliminate the bone resonance and isolate the signal from the membrane phospholipids by subtraction. Selective saturation of the phospholipid resonance increases the clarity of the sharp peaks downfield from the phosphocreatine peak. Selective saturation 3-D chemical shift imaging techniques were used to create a localized phospholipid profile of the entire brain simultaneously. Monitoring localized phospholipid concentration may be important in studying demyelinating diseases. PMID:7848814

  6. Degradation of black phosphorus: a real-time 31P NMR study

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Yang, Bingchao; Wan, Bensong; Xi, Xuekui; Zeng, Zhongming; Liu, Enke; Wu, Guangheng; Liu, Zhongyuan; Wang, Wenhong

    2016-09-01

    In this work, degradation behaviors and mechanisms of black phosphorus (BP) crystals in air under ambient conditions were investigated by nuclear magnetic resonance spectroscopy. It has been found that the 31P NMR line intensity for BP decreases exponentially during aging even at the very first several hours, suggesting the origin of the degradation of transport properties. In addition to phosphoric acid, new phosphorous acid was also well resolved in the final aging products. Moreover, BP has been found to be stable in water without the presence of oxygen molecules. These findings are relevant for better understanding of degradation behaviors of BP upon aging and should be helpful for overcoming a barrier that might hamper progress toward applications of BP as a 2D material.

  7. Inhibition mechanisms of Zn precipitation on aluminum oxide by glyphosate: a 31P NMR and Zn EXAFS study.

    PubMed

    Li, Wei; Wang, Yu-Jun; Zhu, Mengqiang; Fan, Ting-Ting; Zhou, Dong-Mei; Phillips, Brian L; Sparks, Donald L

    2013-05-01

    In this research, the effects of glyphosate (GPS) on Zn sorption/precipitation on γ-alumina were investigated using a batch technique, Zn K-edge EXAFS, and (31)P NMR spectroscopy. The EXAFS analysis revealed that, in the absence of glyphosate, Zn adsorbed on the aluminum oxide surface mainly as bidentate mononuclear surface complexes at pH 5.5, whereas Zn-Al layered double hydroxide (LDH) precipitates formed at pH 8.0. In the presence of glyphosate, the EXAFS spectra of Zn sorption samples at pH 5.5 and 8.0 were very similar, both of which demonstrated that Zn did not directly bind to the mineral surface but bonded with the carboxyl group of glyphosate. Formation of γ-alumina-GPS-Zn ternary surface complexes was further suggested by (31)P solid state NMR data which indicated the glyphosate binds to γ-alumina via a phosphonate group, bridging the mineral surface and Zn. Additionally, we showed the sequence of additional glyphosate and Zn can influence the sorption mechanism. At pH 8, Zn-Al LDH precipitates formed if Zn was added first, and no precipitates formed if glyphosate was added first or simultaneously with Zn. In contrast, at pH 5.5, only γ-alumina-GPS-Zn ternary surface complexes formed regardless of whether glyphosate or Zn was added first or both were added simultaneously. PMID:23550510

  8. Inhibition mechanisms of Zn precipitation on aluminum oxide by glyphosate: a 31P NMR and Zn EXAFS study.

    PubMed

    Li, Wei; Wang, Yu-Jun; Zhu, Mengqiang; Fan, Ting-Ting; Zhou, Dong-Mei; Phillips, Brian L; Sparks, Donald L

    2013-05-01

    In this research, the effects of glyphosate (GPS) on Zn sorption/precipitation on γ-alumina were investigated using a batch technique, Zn K-edge EXAFS, and (31)P NMR spectroscopy. The EXAFS analysis revealed that, in the absence of glyphosate, Zn adsorbed on the aluminum oxide surface mainly as bidentate mononuclear surface complexes at pH 5.5, whereas Zn-Al layered double hydroxide (LDH) precipitates formed at pH 8.0. In the presence of glyphosate, the EXAFS spectra of Zn sorption samples at pH 5.5 and 8.0 were very similar, both of which demonstrated that Zn did not directly bind to the mineral surface but bonded with the carboxyl group of glyphosate. Formation of γ-alumina-GPS-Zn ternary surface complexes was further suggested by (31)P solid state NMR data which indicated the glyphosate binds to γ-alumina via a phosphonate group, bridging the mineral surface and Zn. Additionally, we showed the sequence of additional glyphosate and Zn can influence the sorption mechanism. At pH 8, Zn-Al LDH precipitates formed if Zn was added first, and no precipitates formed if glyphosate was added first or simultaneously with Zn. In contrast, at pH 5.5, only γ-alumina-GPS-Zn ternary surface complexes formed regardless of whether glyphosate or Zn was added first or both were added simultaneously.

  9. 31P-NMR SPECTROSCOPY OF RAT LIVER DURING SIMPLE STORAGE OR CONTINUOUS HYPOTHERMIC PERFUSION1

    PubMed Central

    Rossaro, Lorenzo; Murase, Noriko; Caldwell, Cary; Farghali, Hassan; Casavilla, Adrian; Starzl, Thomas E.; Ho, Chien; Van Thiel, David H.

    2010-01-01

    SUMMARY The ATP content and intracellular pH (pHi)3 of isolated rat liver before, during, and after cold preservation in either UW-lactobionate (UW, n=10) or Euro-Collins (EC, n=8) solutions were monitored using phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopy. The 31P-NMR spectra were obtained on a 4.7-Tesla system operating at 81 MHz. Fructose metabolism, liver enzyme release, O2 consumption, and rat survival after liver transplantation were also evaluated. During simple cold storage (SCS), the ATP level declined to undetectable levels with both preservation solutions while the pHi declined to approximately 7.0. In contrast, during continuous hypothermic perfusion (CHP), hepatic ATP levels remained measurable during the 24-hour EC preservation and actually increased significantly (p>0.01) during UW preservation. After reperfusion at 37°C with Krebs-lactate, the SCS livers treated with EC differed significantly from the UW livers in terms of their ATP and pHi as well as their response to a fructose challenge. In contrast, livers undergoing CHP demonstrated similar behaviors with both solutions. These results demonstrate an increase in the hepatic ATP content during CHP which occurs with UW but is not seen with EC. On the other hand, only livers that were simply stored with UW achieved significant survival after transplant, while CHP livers were affected by vascular damage as demonstrated by fatal thrombosis after transplant. These data suggest that ATP content is not the only determinant of good liver function although a system of hypothermic perfusion might further improve liver preservation efficacy should injury to vascular endothelium be avoided. PMID:1402332

  10. P-O-B(3) linkages in borophosphate glasses evidenced by high field (11)B/(31)P correlation NMR.

    PubMed

    Tricot, G; Raguenet, B; Silly, G; Ribes, M; Pradel, A; Eckert, H

    2015-06-01

    The long-standing debate about the presence of P-O-B(3) linkages in glasses has been solved by high-field scalar correlation NMR. Previously suggested by dipolar NMR methods, the presence of such species has been definitively demonstrated by (11)B((31)P) J-HMQC NMR techniques. The results indicate that borophosphate networks contain P-O-B(3) bonds and thus present a higher degree of atomic homogeneity than previously thought. PMID:25891539

  11. Modified Prony Method to Resolve and Quantify in Vivo31P NMR Spectra of Tumors

    NASA Astrophysics Data System (ADS)

    Barone, P.; Guidoni, L.; Ragona, R.; Viti, V.; Furman, E.; Degani, H.

    Prony's method, successfully used in processing NMR signals, performs poorly at low signal-to-noise ratios. To overcome this problem, a statistical approach has been adopted by using Prony's method as a sampling device from the distribution associated with the true spectrum. Specifically, Prony's method is applied for each regression order p and number of data points n, both considered in a suitable range, and the estimates of frequencies, amplitudes, and decay factors are pooled separately. A histogram of the pooled frequencies is computed and, looking at the histogram, a lower and an upper frequency bound for each line of interest is determined. All frequency estimates in each of the determined intervals as well as associated decay factors and amplitudes are considered to be independent normal variates. A mean value and a corresponding 95% confidence interval are computed for each parameter. 31P NMR signals from MCF7 human breast cancer cells, inoculated into athymic mice and which developed into tumors, have been processed with traditional methods and with this modified Prony's method. The main components of the phosphomonoester peak, namely those deriving from phosphorylcholine and phosphorylethanolamine, are always well resolved with this new approach and their relative amplitudes can be consequently evaluated. Peak intensities of these two signals show different behavior during treatment of tumors with the antiestrogenic drug tamoxifen. The results of this new approach are compared with those obtainable with traditional techniques.

  12. (31)P NMR study of post mortem changes in pig muscle.

    PubMed

    Miri, A; Talmant, A; Renou, J P; Monin, G

    1992-01-01

    The rate and the extent of post mortem pH changes in pig muscle largely determine pork quality. Fast pH fall combined with low ultimate pH leads to pale soft exudative (PSE) meat; high ultimate pH leads to dark firm dry (DFD) meat. Post mortem metabolism was studied in pig muscle using(31)P NMR. Fifteen pigs, i.e. 7 Large White pigs and 8 Pietrain pigs, were used. Five pigs of each breed were slaughtered, taking care to minimize preslaughter stress. The other pigs (3 Large Whites and 2 Pietrains) were injected with 0·1 mg adrenaline per kg liveweight before slaughter, in order to increase meat ultimate pH. All the animals were killed by electronarcosis and exsanguination. Three of the adrenaline-treated pigs (1 Large White and 2 Pietrains) gave meat with ultimate pH above 6 (DFD meat). The pigs with normal muscle ultimate pH, i.e. 6 Large Whites and 6 Pietrains, had very variable rates of post mortem muscle metabolism (pH at 30 min after slaughter: 6·17-6·85 in Large Whites; 6·04-6·23 in Pietrains). The relationships between pH and ATP changes were similar in all pigs showing normal muscle ultimate pH, whereas ATP disappeared at a high pH value (on average pH 6·4) in pigs with high ultimate pH. The course of post mortem biochemical changes in a given animal could be predicted rather well by examination of a single(31)P NMR spectrum obtained around 30 min after death. At this time, muscle with a low rate of metabolism simultaneously showed medium to high pH, high ATP content (4-6·8 μmol/g) and rather low Pi content (6-14 μmol/g); muscle with a fast rate of metabolism (PSE-prone muscle) had low pH, low to medium ATP content (1·1-4 μmol/g) and generally high phosphomonoester (PME) content (9-23 μmol/g); muscle with high ultimate pH (DFD-prone muscle) had high pH, low PME content (4-8 μmol/g) and high Pi content (22-27 μmol/g).

  13. Interaction between beta-Purothionin and dimyristoylphosphatidylglycerol: a (31)P-NMR and infrared spectroscopic study.

    PubMed Central

    Richard, Julie-Andrée; Kelly, Isabelle; Marion, Didier; Pézolet, Michel; Auger, Michèle

    2002-01-01

    The interaction of beta-purothionin, a small basic and antimicrobial protein from the endosperm of wheat seeds, with multilamellar vesicles of dimyristoylphosphatidylglycerol (DMPG) was investigated by (31)P solid-state NMR and infrared spectroscopy. NMR was used to study the organization and dynamics of DMPG in the absence and presence of beta-purothionin. The results indicate that beta-purothionin does not induce the formation of nonlamellar phases in DMPG. Two-dimensional exchange spectroscopy shows that beta-purothionin decreases the lateral diffusion of DMPG in the fluid phase. Infrared spectroscopy was used to investigate the perturbations, induced by beta-purothionin, of the polar and nonpolar regions of the phospholipid bilayers. At low concentration of beta-purothionin, the temperature of the gel-to-fluid phase transition of DMPG increases from 24 degrees C to ~33 degrees C, in agreement with the formation of electrostatic interactions between the cationic protein and the anionic phospholipid. At higher protein concentration, the lipid transition is slightly shifted toward lower temperature and a second transition is observed below 20 degrees C, suggesting an insertion of the protein in the hydrophobic core of the lipid bilayer. The results also suggest that the presence of beta-purothionin significantly modifies the lipid packing at the surface of the bilayer to increase the accessibility of water molecules in the interfacial region. Finally, orientation measurements indicate that the alpha-helices and the beta-sheet of beta-purothionin have tilt angles of ~60 degrees and 30 degrees, respectively, relative to the normal of the ATR crystal. PMID:12324425

  14. 31P NMR Kinetics Study of Cardiac Metabolism under Mild Hypoxia

    NASA Astrophysics Data System (ADS)

    Goudemant, J. F.; Elst, L. V.; Vanhaverbeke, Y.; Muller, R. N.

    The effects of mild hypoxia on the metabolic and mechanical functions of isovolumic perfused rat hearts have been studied. 31P NMR has been used to follow the metabolite concentrations as well as the intracellular pH. Additionally, the energy transfer through the creatine kinase reaction was estimated by the magnetization-transfer technique. The needs of myofibrillar energy and of mitochondrial ATP production have been assessed through mechanical activity and oxygen-consumption rate. It has been observed that mild hypoxia simultaneously impairs contractile and metabolic functions. The aerobic ATP production is maintained under these conditions while anaerobic energy metabolism seems accelerated. The accumulation of some metabolites (ADP and P i) and the decrease of creatine kinase forward flux ( Vfor) tend, however, to prove that ATP availability for myofibrils is lowered. The large aerobic energy production observed must therefore be explained by an energy wastage in the mitochondria. In spite of normal ATP concentration, a contractile dysfunction is observed and can be explained by the P i accumulation, which is known to impair the use of the myofibrillar ATP. Another hypothesis supported by the magnetization transfer experiments is the poor ATP availability resulting from the ATP wastage in the mitochondria and from the inefficient energy transport by the PCr-Cr shuttle.

  15. Activation of dehydrogenase activity and cardiac respiration: A sup 31 P-NMR study

    SciTech Connect

    Katz, L.A.; Koretsky, A.P.; Balaban, R.S. )

    1988-07-01

    {sup 31}P-NMR studies were performed to determine the tissue phosphate and oxygen consumption effects of known maneuvers on the activation of pyruvate dehydrogenase during work jumps in the perfused rat heart. In control studies of the glucose-perfused heart, work jumps, with pacing, resulted in a 32% increase in oxygen consumption ({dot char}Qo{sub 2}) from 1.72 {plus minus} 0.09 to 2.29 {plus minus} 0.12 mmol O{sub 2}{center dot}h{sup {minus}1}{center dot}g dry wt{sup {minus}1}. During this transition no significant change in the high energy phosphates were detected. In contrast, work jumps did cause changes in the phosphates when the activation of pyruvate dehydrogenase was blocked with 2.5 {mu}g of ruthenium red per milliliter or maximally stimulated with 11 mM pyruvate before the increase in work. The observed increase in {dot char}Qo{sub 2} and inorganic phosphate and calculated increase in ADP are consistent with these phosphates controlling mitochondrial respiration under these conditions. These results suggest that the activation of pyruvate dehydrogenase and/or other dehydrogenases may be an important step in the orchestration of work and {dot char}Qo{sub 2}.

  16. 31P-NMR studies of isolated adult heart cells: effect of myoglobin inactivation.

    PubMed

    Gupta, R K; Wittenberg, B A

    1991-10-01

    31P nuclear magnetic resonance (NMR) studies of isolated adult rat heart cells revealed that the cells maintained high-energy phosphates for up to 6 h in polyamide hollow fibers perfused with well-oxygenated nutrient medium. Glucose plus pyruvate superfused heart cells maintained [phosphocreatine]/[ATP] at 1.4 +/- 0.1, internal pH at 7.09 +/- 0.04 (external pH = 7.25), and intracellular free Mg2+ at 0.51 +/- 0.04 mM. In glucose-containing media, hypoxia was accompanied by a reversible decrease in intracellular ATP and phosphocreatine of approximately 50% and 80%, respectively, while the intracellular free Mg2+ was reversibly increased by 40%. However, inhibition of glycolysis by iodoacetate in aerobic pyruvate-containing medium did not significantly alter high-energy phosphate content. Inactivation of intracellular myoglobin with 1-2 mM sodium nitrite, which reduces the steady-state respiratory oxygen consumption rate by 30%, caused a significant (30%) decrease in intracellular phosphocreatine peak, which was reversed upon removal of sodium nitrite. The nitrite-induced decrease in phosphocreatine was also observed in iodoacetate-treated myocytes but not in oligomycin-treated cells. These results indicate that functional myoglobin enhances high-energy phosphate synthesis in well-oxygenated myocytes. PMID:1928397

  17. Molybdenum modified phosphate glasses studied by 31P MAS NMR and Raman spectroscopy.

    PubMed

    Szumera, Magdalena

    2015-02-25

    Glasses have been synthesized in the system P2O5-SiO2-K2O-MgO-CaO modified by addition of MoO3. Glasses were prepared by conventional fusion method from 40 g batches. The influence of Mo-cations on the analysed glass structure was investigated by means of Raman and (31)P MAS-NMR techniques. It has been found that molybdate units can form Mo[MoO4/MoO6]-O-P and/or Mo[MoO4/MoO6]-O-Si bonds with non-bridging oxygens atoms of Q2 methaphosphate units, resulting in the transformation of chain methaphosphate structure into pyrophosphate and finally into orthophosphate structure. It has been also found that increasing amount of MoO3 in the structure of investigated glasses causes their gradual depolymerization and molybdenum ions in the analysed glass matrix act as modifying cations.

  18. /sup 31/P NMR characterization of graded traumatic brain injury in rats

    SciTech Connect

    Vink, R.; McIntosh, T.K.; Yamakami, I.; Faden, A.I.

    1988-01-01

    Irreversible tissue injury following central nervous system trauma is believed to result from both mechanical disruption at the time of primary insult, and more delayed autodestructive processes. These delayed events are associated with various biochemical changes, including alterations in phosphate energy metabolism and intracellular pH. Using /sup 31/P NMR, we have monitored the changes in phosphorus energy metabolism and intracellular pH in a single hemisphere of the rat brain over an 8-h period following graded, traumatic, fluid percussion-induced brain injury. Following trauma the ratio of phosphocreatine to inorganic phosphate (PCr/Pi) declined in each injury group. This decline was transitory with low injury (1.0 +/- 0.5 atm), biphasic with moderate (2.1 +/- 0.4 atm) and high (3.9 +/- 0.9 atm) injury, and sustained following severe injury (5.9 +/- 0.7 atm). The initial PCr/Pi decline in the moderate and high injury groups was associated with intracellular acidosis; however, the second decline occurred in the absence of any pH changes. Alterations in ATP occurred only in severely injured animals and such changes were associated with marked acidosis and 100% mortality rate. After 4h, the posttraumatic PCr/Pi ratio correlated linearly with the severity of injury. We suggest that a reduced posttraumatic PCr/Pi ratio may be indicative of altered mitochondrial energy production and may predict a reduced capacity of the cell to recover from traumatic injury.

  19. Interaction of antiaggregant molecule ajoene with membranes. An ESR and 1H, 2H, 31P-NMR study.

    PubMed

    Debouzy, J C; Neumann, J M; Hervé, M; Daveloose, D; Viret, J; Apitz-Castro, R

    1989-01-01

    The structure of ajoene, a molecule extracted from garlic, has been studied by 1H-NMR and its interaction with model membranes by 1H-, 2H-, 31-P-NMR and ESR experiments. This study clearly shows that the ajoene molecule is located deep in the layer and is close to the interlayer medium. Moreover while NMR experiments show that the membrane structure is only slightly affected by the presence of ajoene, ESR experiments reveal significant modifications in phospholipid dynamics. This interaction, observed before with the phenothiazine derivative, promazine, results in an increase of the membrane fluidity in its hydrophobic part and could be related to clinical properties of ajoene.

  20. Gated /sup 31/P NMR study of tetanic contraction in rat muscle depleted of phosphocreatine

    SciTech Connect

    Shoubridge, E.A.; Radda, G.K.

    1987-05-01

    Rats were fed a diet containing 1% ..beta..-guanidino-propionic acid (GPA) for 6-12 wk to deplete their muscles of phosphocreatine (PCr). Gated /sup 31/P nuclear magnetic resonance (NMR) spectra were obtained from the gastrocnemius-plantaris muscle at various time points during either a 1- or 3-s isometric tetanic contraction using a surface coil. The energy cost of a 1-s tetanus in unfatigued control rat muscle was 48.4 ..mu..mol ATP x g dry wt/sup -1/ x s/sup -1/ and was largely supplied by PCr; anaerobic glycogenolysis was negligible. In GPA-fed rats PCr was undetectable after 400 ms. This had no effect on initial force generated per gram, which was not significantly different from controls. Developed tension in a 3-s tetanus in GPA-fed rats could be divided into a peak phase (duration 0.8-0.9 s) and a plateau phase (65% peak tension) in which PCr was undetectable and the (ATP) was < 20% of that in control muscle. Energy from glycogenolysis was sufficient to maintain force generation at this submaximal level. Mean net glycogen utilization per 3-s tetanus was 78% greater than in control muscle. However, the observed decrease in intracellular pH was less than that expected from energy budget calculations, suggesting either increased buffering capacity or modulation of ATP hydrolysis in the muscles of GPA-fed rats. The results demonstrate that the transport role of PCr is not essential in contracting muscle in GPA-fed rats. PCr is probably important in this regard in the larger fibers of control muscle. Although fast-twitch muscles depleted of PCr have nearly twice the glycogen reserves of control muscle, glycogenolysis is limited in its capacity to fill the role of PCr as an energy buffer under conditions of maximum ATP turnover.

  1. (31)P Solid-State NMR study of the chemical setting process of a dual-paste injectable brushite cements.

    PubMed

    Legrand, A P; Sfihi, H; Lequeux, N; Lemaître, J

    2009-10-01

    The composition and evolution of a brushite-type calcium phosphate cement was investigated by Solid-State NMR and X-ray during the setting process. The cement is obtained by mixing beta-tricalcium phosphate [Ca(3)(PO(4))(2), beta-TCP] and monocalcium phosphate monohydrate [Ca(H(2)PO(4))(2).H(2)O, MCPM] in presence of water, with formation of dicalcium phosphate dihydrate or brushite [CaHPO(2).2H(2)O, DCPD]. Analysis of the initial beta-TCP paste has shown the presence of beta-calcium pyrophosphate [Ca(2)P(2)O(7), beta-CPy] and that of the initial MCPM a mixture of MCPM and dicalcium phosphate [CaHPO(4), DCP]. Follow-up of the chemical composition by (31)P Solid-State NMR enables to show that the chemical setting process appeared to reach an end after 20 min. The constant composition observed at the end of the process was similarly determined.

  2. Distinguishing bicontinuous lipid cubic phases from isotropic membrane morphologies using (31)P solid-state NMR spectroscopy.

    PubMed

    Yang, Yu; Yao, Hongwei; Hong, Mei

    2015-04-16

    Nonlamellar lipid membranes are frequently induced by proteins that fuse, bend, and cut membranes. Understanding the mechanism of action of these proteins requires the elucidation of the membrane morphologies that they induce. While hexagonal phases and lamellar phases are readily identified by their characteristic solid-state NMR line shapes, bicontinuous lipid cubic phases are more difficult to discern, since the static NMR spectra of cubic-phase lipids consist of an isotropic (31)P or (2)H peak, indistinguishable from the spectra of isotropic membrane morphologies such as micelles and small vesicles. To date, small-angle X-ray scattering is the only method to identify bicontinuous lipid cubic phases. To explore unique NMR signatures of lipid cubic phases, we first describe the orientation distribution of lipid molecules in cubic phases and simulate the static (31)P chemical shift line shapes of oriented cubic-phase membranes in the limit of slow lateral diffusion. We then show that (31)P T2 relaxation times differ significantly between isotropic micelles and cubic-phase membranes: the latter exhibit 2 orders of magnitude shorter T2 relaxation times. These differences are explained by the different time scales of lipid lateral diffusion on the cubic-phase surface versus the time scales of micelle tumbling. Using this relaxation NMR approach, we investigated a DOPE membrane containing the transmembrane domain (TMD) of a viral fusion protein. The static (31)P spectrum of DOPE shows an isotropic peak, whose T2 relaxation times correspond to that of a cubic phase. Thus, the viral fusion protein TMD induces negative Gaussian curvature, which is an intrinsic characteristic of cubic phases, to the DOPE membrane. This curvature induction has important implications to the mechanism of virus-cell fusion. This study establishes a simple NMR diagnostic probe of lipid cubic phases, which is expected to be useful for studying many protein-induced membrane remodeling phenomena

  3. Characterization of different precursors and activated vanadium phosphate catalysts by [sup 31]P NMR spin echo mapping

    SciTech Connect

    Sananes, M.T. Univ. of Liverpool ); Tuel, A.; Volta, J.C. ); Hutchings, G.J. )

    1994-07-01

    In a previous publication, the authors emphasized the use of the spin echo mapping technique applied to [sup 31]P NMR to obtain information on the valence state of vanadium in different environments of phosphorus for several VPO reference structures. In this paper, the authors describe the use of this technique, combined with knowledge of reference phases, to study VPO catalysts prepared from different precursors and used for the oxidation of n-butane into maleic anhydride. 9 refs., 2 figs., 1 tab.

  4. /sup 31/P NMR saturation-transfer and /sup 13/C NMR kinetic studies of glycolytic regulation during anaerobic and aerobic glycolysis

    SciTech Connect

    Campbell-Burk, S.L.; den Hollander, J.A.; Alger, J.R.; Shulman, R.G.

    1987-11-17

    /sup 31/P NMR saturation-transfer techniques have been employed in glucose-gown derepressed yeast to determine unidirectional fluxes in the upper part of the Embden-Meyerhof-Parnas pathway. The experiments were performed during anaerobic and aerobic glycolysis by saturating the ATP/sub ..gamma../ resonances and monitoring changes in the phosphomonoester signals from glucose 6-phosphate and fructose 1,6-bisphosphate. These experiments were supplemented with /sup 13/C NMR measurements of glucose utilization rates and /sup 13/C NMR label distribution studies. Combined with data obtained previously from radioisotope measurement, these /sup 31/P and /sup 13/C NMR kinetic studies allowed estimation of the net glycolytic flow in addition to relative flows through phosphofructokinase (PFK) and Fru-1,6-P/sub 2/ase during anaerobic and aerobic glycolysis. The /sup 31/P NMR saturation-transfer results are consistent with previous results obtained from measurements of metabolite levels, radioisotope data, and /sup 13/C NMR studies, providing additional support for in vivo measurement of the flows during glycolysis.

  5. Absolute shielding scale for 31P from gas-phase NMR studies

    NASA Astrophysics Data System (ADS)

    Jameson, Cynthia J.; De Dios, Angel; Keith Jameson, A.

    1990-04-01

    Differences in the 31P nuclear shielding in the zero-pressure limit have been measured in seven compounds. An absolute 31P shielding scale based on the PH 3 molecular beam data is established and the absolute shielding of the standard liquid reference (85% aqueous H 3PO 4) is found to be 328.35 ppm, based on PH 3 being 594.45 ± 0.63 ppm. Comparisons with ab initio calculations show that calculations using local origins (the IGLO method) are in good agreement with experiment.

  6. Intracellular pH and inorganic phosphate content of heart in vivo: A sup 31 P-NMR study

    SciTech Connect

    Katz, L.A.; Swain, J.A.; Portman, M.A.; Balaban, R.S. )

    1988-07-01

    Studies were performed to determine the contribution of red blood cells to the {sup 31}P-nuclear magnetic resonance (NMR) spectrum of the canine heart in vivo and the feasibility of measuring myocardial intracellular phosphate and pH. This was accomplished by replacing whole blood with a perfluorochemical perfusion emulsion blood substitute, Oxypherol, and noting the difference in the {sup 31}P-NMR spectrum of the heart. NMR data were collected with a NMR transmitter-receiver coil on the surface of the distal portion of the left ventricle. These studies demonstrated that a small contribution from 2,3-diphosphoglycerate (2,3-DPG) and phosphodiesters in the blood could be detected. The magnitude and shift of these blood-borne signals permitted the relative quantification of intracellular inorganic phosphate (P{sub i}) content as well as intracellular pH. Under resting conditions, the intracellular ATP/P{sub i} was 7.0 {plus minus} 0.08. This corresponds to a free intracellular P{sub 1} content of {approx} 0.8 {mu}mol./g wet wt. The intracellular pH was 7.10 {plus minus} 0.01. Acute respiratory alkalosis and acidosis, with the arterial pH ranging from {approximately}7.0 to 7.7, resulted in only small changes in the intracellular pH. These latter results demonstrate an effective myocardial intracellular proton-buffering mechanism in vivo.

  7. Effect of Ca:Mg ratio on precipitated P species identified using 31P solid state NMR

    NASA Astrophysics Data System (ADS)

    Manimel Wadu, M.

    2009-04-01

    M.C.W. Manimel Wadu1, O.O Akinremi1, S. Kroeker2 1Department of Soil Science, University of Manitoba, Winnipeg, R3T 2N2, Canada 2Department of Chemistry, University of Manitoba, Winnipeg, R3T 2N2, Canada Agronomic efficiency of added P fertilizer is reduced by the precipitation reactions with the exchangeable Ca and Mg in calcareous soils. We hypothesized that the ratio of Ca to Mg on the soil exchange complex will affect the species of P that is precipitated and its solubility in the soil. A laboratory experiment was conducted using a model calcareous soil system which was composed of resin (Amberlite IRP69) and sand coated with CaCO3 packed into a column. The resin was pre saturated with Ca and Mg in order to achieve five different saturation ratios of Ca:Mg approximately as 100:0, 70:30, 50:50, 30:70 and 0:100. Monoammonium Phosphate was applied to the soil surface to simulate one-dimensional diffusive transport. The column was then incubated for 2 weeks. Chemical analysis for water and acid soluble P, pH, NH4, Ca and Mg was performed on 2mm sections of the soil to a depth of 10 cm. This paper will present and discuss the distribution of P along the soil column. Unlike similar studies that have speculated on the precipitation of P, this study will identify and quantify the P species that is formed using 31P solid state NMR technique. Such knowledge will be helpful in understanding the effect of Ca and Mg on P availability in calcareous system and the role of each cation on P precipitation. Key words: P fertilizers, Ca, Mg, model system, solid state NMR

  8. Using 31P-NMR to investigate dynamics of soil phosphorus compounds in the Rothamsted Long Term Experiments

    NASA Astrophysics Data System (ADS)

    Blackwell, Martin; Turner, Ben; Granger, Steve; Hooper, Tony; Darch, Tegan; Hawkins, Jane; Yuan, Huimin; McGrath, Steve

    2015-04-01

    The technique of 31P-NMR spectroscopy has done more to advance the knowledge of phosphorus forms (especially organic phosphorus) in environmental samples than any other method. The technique has advanced such that specific compounds can be identified where previously only broad categories such as orthophosphate monoesters and diesters were distinguishable. The Soil Archive and Long Term Experiments at Rothamsted Research, UK, potentially provides an unequalled opportunity to use this technique to observe changes in soil phosphorus compounds with time and under different treatments, thereby enhancing our understanding of phosphorus cycling and use by plants. Some of the earliest work using this technique on soils was carried out by Hawkes et al. in 1984 and this used soils from two of the oldest Rothamsted Long Term Experiments, namely Highfield and Park Grass. Here we revisit the samples studied in this early work and reanalyse them using current methodology to demonstrate how the 31P-NMR technique has advanced. We also present results from a study on the phosphorus chemistry in soils along the Hoosfield acid strip (Rothamsted, UK), where a pH gradient from 3.7 to 7.8 occurs in a single soil with little variation in total phosphorus (mean ± standard deviation 399 ± 27 mg P kg-1). Soil pH was found to be an important factor in determining the proportion of phosphomonoesters and phosphodiesters in the soil organic phosphorus, although total organic phosphorus concentrations were a relatively consistent proportion of the total soil phosphorus (36 ± 2%) irrespective of soil pH. Key words. 31P-NMR, soil organic phosphorus, long term experiments, Hoosfield acid strip

  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. Phytate degradation by lactic acid bacteria and yeasts during the wholemeal dough fermentation: a 31P NMR study.

    PubMed

    Reale, Anna; Mannina, Luisa; Tremonte, Patrizio; Sobolev, Anatoli P; Succi, Mariantonietta; Sorrentino, Elena; Coppola, Raffaele

    2004-10-01

    myo-Inositol hexaphosphate (IP6) is the main source of phosphorus in cereal grains, and therefore, in bakery products. Different microorganisms such as yeasts and lactic acid bacteria have phytase enzymes able to hydrolyze IP6 during the wholemeal breadmaking. In this paper, the phytase activity of Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus curvatus, and Saccharomyces cerevisiae strains, isolated from southern Italian sourdoughs, is assayed using the (31)P NMR technique. The sourdough technology based on the use of lactic acid bacteria in the breadmaking is finally suggested.

  11. Intrauterine fetal brain NMR spectroscopy: 1H and 31P studies in rats

    SciTech Connect

    Nakada, T.; Kwee, I.L.; Suzuki, N.; Houkin, K. )

    1989-11-01

    Fetal brain metabolism was investigated in utero noninvasively using multinuclear nuclear magnetic resonance spectroscopy in rats at two representative prenatal stages: early (17-18 days) and late (20-21 days) stages. Phosphorus-31 (31P) spectroscopy revealed that phosphocreatine is significantly lower in the early stage and increases to the level of early neonates by the late prenatal stage. Intracellular pH at the early stage was found to be strikingly high (7.52 +/- 0.21) and decreased to a level similar to that of neonates by the late stage (7.29 +/- 0.07). Phosphomonoester levels at both stages were similar to the values reported for early neonates. Water-suppressed proton (1H) spectroscopy demonstrated a distinctive in vivo fetal brain spectral pattern characterized by low levels of N-acetyl aspartate and high levels of taurine. High-resolution proton spectroscopy and homonuclear chemical-shift correlate spectroscopy of brain perchloric acid extracts confirmed these in vivo findings. In vitro 31P spectroscopy of acidified chloroform methanol extracts showed the characteristic membrane phospholipid profiles of fetal brain. The phosphatidylethanolamine (PE)-to-phosphatidylcholine (PC) ratio (PE/PC) did not show significant changes between the two stages at 0.40 +/- 0.11, a value similar to that of early neonates.

  12. 2D exchange 31P NMR spectroscopy of bacteriophage M13 and tobacco mosaic virus.

    PubMed Central

    Magusin, P C; Hemminga, M A

    1995-01-01

    Two-dimensional (2D) exchange 31P nuclear magnetic resonance spectroscopy is used to study the slow overall motion of the rod-shaped viruses M13 and tobacco mosaic virus in concentrated gels. Even for short mixing times, observed diagonal spectra differ remarkably from projection spectra and one-dimensional spectra. Our model readily explains this to be a consequence of the T2e anisotropy caused by slow overall rotation of the viruses about their length axis. 2D exchange spectra recorded for 30% (w/w) tobacco mosaic virus with mixing times < 1 s do not show any off-diagonal broadening, indicating that its overall motion occurs in the sub-Hz frequency range. In contrast, the exchange spectra obtained for 30% M13 show significant off-diagonal intensity for mixing times of 0.01 s and higher. A log-gaussian distribution around 25 Hz of overall diffusion coefficients mainly spread between 1 and 10(3) Hz faithfully reproduces the 2D exchange spectra of 30% M13 recorded at various mixing times in a consistent way. A small but notable change in diagonal spectra at increasing mixing time is not well accounted for by our model and is probably caused by 31P spin diffusion. PMID:7756532

  13. FTIR and {sup 31}P-NMR spectroscopic analyses of surface species in phosphate-catalyzed lactic acid conversion

    SciTech Connect

    Gunter, G.C.; Tam, M.S.; Miller, D.J.

    1996-11-01

    The surface species present on silica/alumina-supported sodium phosphates, active catalysts for the conversion of lactic acid to acrylic acid and 2,3-pentanedione, are examined by pre- and postreaction MAS {sup 31}P-NMR and FTIR spectroscopies. Species present following lactic acid conversion are identified by transmission FTIR of phosphates supported on silicon disks (as a model catalyst system) and verified by {sup 31}P-NMR and diffuse reflectance IR spectroscopy of actual catalysts used in reaction. Monosodium phosphate (NaH{sub 2}PO{sub 4}) condenses to a mixture of sodium polyphosphate (NaPO{sub 3}){sub n} and sodium trimetaphosphate (Na{sub 3}P{sub 3}O{sub 9}), which exhibit little catalytic activity for converting lactic acid to desired products. Disodium phosphate (Na{sub 2}HPO{sub 4}) condenses to tetrasodium pyrophosphate (Na{sub 4}P{sub 2}O{sub 7}), and proton transfer from lactic acid to pyrophosphate results in the formation of sodium lactate. Trisodium phosphate (Na{sub 3}PO{sub 4}) accepts a proton from lactic acid to form sodium lactate and disodium phosphate, which condenses to pyrophosphate. The presence of pyrophosphate and sodium lactate on supported disodium and trisodium phosphates explains their similar catalytic properties; the larger quantity of sodium lactate present on trisodium phosphate leads to higher conversions at lower temperatures. 40 refs., 14 figs., 2 tabs.

  14. Local structure of spin Peierls compound TiPO4: 47/49Ti and 31P NMR study

    NASA Astrophysics Data System (ADS)

    Stern, Raivo; Heinmaa, Ivo; Leitmäe, Alexander; Joon, Enno; Tsirlin, Alexander; Kremer, Reinhard; Glaum, Robert

    TiPO4 structure is made of slightly corrugated TiO2 ribbon chains of edge-sharing TiO6 octahedra. The almost perfect 1D spin 1/2 Ti3 + chains are well separated by PO4 tetrahedra. By magnetic susceptibility and MAS-NMR measurements [1] it was shown that TiPO4 has nonmagnetic singlet ground state with remarkably high Spin-Peierls (SP) transition temperature. The high-T magnetic susceptibility of TiPO4 follows well that of a S =1/2 Heisenberg chain with very strong nearest-neighbor AF spin-exchange coupling constant of J =965K. On cooling TiPO4 shows two successive phase transitions at 111K and 74K, with incommensurate (IC) SP phase between them. We studied local structure and dynamics in TiPO4 single crystal using 47/49Ti and 31P NMR in the temperature range 40K to 300K, and determined the principal values and orientation of the magnetic shift tensors for 31P and 47,49Ti nuclei. Since 47,49Ti (S =5/2 and S =7/2, respectively) have quadrupolar moments, we also found the principal axis values and orientations of the electric field gradient (efg) tensor in SP phase and at 295K. In SP phase the structure contains 2 magnetically inequivalent P sites and only one Ti site. From the T-dependence of the relaxation rate of 31P and 47Ti nuclei we determined activation energy Ea = 550 K for spin excitations in SP phase. J. Law et al ., PRB 83, 180414(R) (2011).

  15. Interactions of glycerol monooleate and dimethylsulphoxide with phospholipids. A differential scanning calorimetry and 31P-NMR study.

    PubMed

    Tilcock, C P; Fisher, D

    1982-03-01

    1. A comparative study has been made of the effects of the fusogens glycerol monooleate and dimethyl-sulphoxide on the polymorphic phase behaviour of dipalmitoyl phosphatidylcholine and dipalmitoyl phosphatidylethanolamine by differential scanning calorimetry and 31P-NMR techniques. 2. Glycerol monooleate induces a reduction in the temperature, cooperativity and enthalpy of the gel to liquid-crystal transitions of dipalmitoyl phosphatidylcholine and dipalmitoyl phosphatidylethanolamine, whereas dimethylsulphoxide induces an increase in the temperature and enthalpy and a reduction in the cooperativity of the gel to liquid-crystal transitions for those same phospholipids. 3. Glycerol monooleate induces the formation of isotropic and hexagonal (HII) phases when mixed with either dipalmitoyl phosphatidylcholine or dipalmitoyl phosphatidylethanolamine. By contrast, in the presence of dimethylsulphoxide, those same phospholipids retain the lamellar configuration observed in the absence of fusogen. 4. These results are discussed in terms of the mechanisms of chemically induced cell fusion.

  16. sup 31 P NMR measurements of the ADP concentration in yeast cells genetically modified to express creatine kinase

    SciTech Connect

    Brindle, K.; Braddock, P.; Fulton, S. )

    1990-04-03

    Rabbit muscle creatine kinase has been introduced into the yeast Saccharomyces cerevisiae by transforming cells with a multicopy plasmid containing the coding sequence for the enzyme under the control of the yeast phosphoglycerate kinase promoter. The transformed cells showed creating kinase activities similar to those found in mammalian heart muscle. {sup 31}P NMR measurements of the near-equilibrium concentrations of phosphocreatine and cellular pH together with measurements of the total extractable concentrations of phosphocreatine and creatine allowed calculation of the free ADP/ATP ratio in the cell. The calculated ratio of approximately 2 was considerably higher than the ratio of between 0.06 and 0.1 measured directly in cell extracts.

  17. Mechanisms of Peptide-Induced Pore Formation in Lipid Bilayers Investigated by Oriented 31P Solid-State NMR Spectroscopy

    PubMed Central

    Bertelsen, Kresten; Dorosz, Jerzy; Hansen, Sara Krogh; Nielsen, Niels Chr.; Vosegaard, Thomas

    2012-01-01

    There is a considerable interest in understanding the function of antimicrobial peptides (AMPs), but the details of their mode of action is not fully understood. This motivates extensive efforts in determining structural and mechanistic parameters for AMP’s interaction with lipid membranes. In this study we show that oriented-sample 31P solid-state NMR spectroscopy can be used to probe the membrane perturbations and -disruption by AMPs. For two AMPs, alamethicin and novicidin, we observe that the majority of the lipids remain in a planar bilayer conformation but that a number of lipids are involved in the peptide anchoring. These lipids display reduced dynamics. Our study supports previous studies showing that alamethicin adopts a transmembrane arrangement without significant disturbance of the surrounding lipids, while novicidin forms toroidal pores at high concentrations leading to more extensive membrane disturbance. PMID:23094079

  18. Observation of myo-inositol 1,2-(cyclic) phosphate in a Morris hepatoma by 31P NMR.

    PubMed

    Graham, R A; Meyer, R A; Szwergold, B S; Brown, T R

    1987-01-01

    We have identified an unusual resonance at 16.5 ppm in the 31P NMR spectrum of a Morris (7777) hepatoma grown in the inguinal fossa of a Buffalo rat as myoinositol 1,2-(cyclic) phosphate. This compound has been observed in all of the 32 tumors examined as well as in cultured cells derived from the tumor, but it has not been observed in normal rat tissues. Its level in the aqueous phase of chloroform/methanol/water extracts of the tumor is 70 +/- 40 nmol/g, wet weight (n = 4). The presence of a breakdown product of phosphatidylinositol at such high levels in a fast growing tumor may provide an important clue for understanding the metabolic defect that results in the malignant growth of this tumor.

  19. Coal liquefaction process streams characterization and evaluation: Estimation of total phenol concentrations in coal liquefaction resids by {sup 31}P NMR spectroscopy

    SciTech Connect

    Mohan, J.T.; Verkade, J.G.

    1992-11-01

    In this study, Iowa State University researchers used {sub 31}P-tagged reagents to derivatize the labile hydrogen functional groups in the THF-soluble portion of 850{degrees}F{sup +} distillation resid materials and the THF-soluble portion of process oils derived from direct coal liquefaction.{sup 31}P-NMR was used to analyze the derivatized samples. NMR peak assignments can be made by comparison to model compounds similarly derivatized. Species can be quantified by integration of the NMR signals. Different {sup 31}P-NMR tagged reagents can be used to produce different degrees of peak resolution in the NMR spectrum. This, in turn, partially dictates the degree of speciation and/or quantification of species, or classes of compounds, that can be accomplished. Iowa State chose a {sup 31}P-tagged reagent (ClPOCMe{sub 2}CMe{sub 2}O) which was shown previously to be particularly useful in the derivatization of phenols. The derivatized samples all exhibited a small group of peaks attributed to amines and a broad group of peaks in the phenol region. The presence of paramagnetic species in the samples caused the NMR signals to broaden. Electron paramagnetic resonance (EPR) spectra confirmed the presence of paramagnetic organic free radicals in selected samples. Various methods were employed to process the NMR data. The complexity and broadness of the phenol peak, however, made speciation of the phenols impractical.

  20. Coal liquefaction process streams characterization and evaluation: Estimation of total phenol concentrations in coal liquefaction resids by [sup 31]P NMR spectroscopy

    SciTech Connect

    Mohan, J.T.; Verkade, J.G. )

    1992-11-01

    In this study, Iowa State University researchers used [sub 31]P-tagged reagents to derivatize the labile hydrogen functional groups in the THF-soluble portion of 850[degrees]F[sup +] distillation resid materials and the THF-soluble portion of process oils derived from direct coal liquefaction.[sup 31]P-NMR was used to analyze the derivatized samples. NMR peak assignments can be made by comparison to model compounds similarly derivatized. Species can be quantified by integration of the NMR signals. Different [sup 31]P-NMR tagged reagents can be used to produce different degrees of peak resolution in the NMR spectrum. This, in turn, partially dictates the degree of speciation and/or quantification of species, or classes of compounds, that can be accomplished. Iowa State chose a [sup 31]P-tagged reagent (ClPOCMe[sub 2]CMe[sub 2]O) which was shown previously to be particularly useful in the derivatization of phenols. The derivatized samples all exhibited a small group of peaks attributed to amines and a broad group of peaks in the phenol region. The presence of paramagnetic species in the samples caused the NMR signals to broaden. Electron paramagnetic resonance (EPR) spectra confirmed the presence of paramagnetic organic free radicals in selected samples. Various methods were employed to process the NMR data. The complexity and broadness of the phenol peak, however, made speciation of the phenols impractical.

  1. /sup 31/P NMR studies of ATP synthesis and hydrolysis kinetics in the intact myocardium

    SciTech Connect

    Kingsley-Hickman, P.B.; Sako, E.Y.; Mohanakrishnan, P.; Robitaille, P.M.L.; From, A.H.L.; Foker, J.E.; Ugurbil, K.

    1987-11-17

    The origin of the nuclear magnetic resonance (NMR)-measurable ATP in equilibrium P/sub i/ exchange and whether it can be used to determine net oxidative ATP synthesis rates in the intact myocardium were examined by detailed measurements of ATP in equilibrium P/sub i/ exchange rates in both directions as a function of the myocardial oxygen consumption rate (MVO/sub 2/) in (1) glucose-perfused, isovolumic rat hearts with normal glycolytic activity and (2) pyruvate-perfused hearts where glycolytic activity was reduced or eliminated either by depletion of their endogenous glycogen or by use of the inhibitor iodoacetate. In glucose-perfused hearts, the P/sub i/ ..-->.. ATP rate measured by the conventional two-site saturation transfer (CST) technique remained constant while MVO2 was increased approximately 2-fold. When the glycolytic activity was reduced, the P/sub i/ ..-->.. ATP rate decreased significantly, demonstrating the existence of a significant glycolytic contribution. The ATP ..-->.. P/sub i/ rates and rate:MVO ratios measured by the multiple-site saturation transfer method at two MVO/sub 2/ levels were equal to the corresponding P/sub i/..-->.. ATP rates and rate:MVO ratios obtained in the absence of a glycolytic contribution. The following conclusions are drawn from these studies: (1) unless the glycolytic contribution to the ATP in equilibrium P/sub i/ exchange is inhibited or is specifically shown not to exist, the myocardial P/sub i/ in equilibrium ATP exchange due to oxidative phosphorylation cannot be studied by NMR; (2) at moderate MVO/sub 2/ levels, the reaction catalyzed by the two glycolytic enzymes glyceraldehyde-3-phosphate dehydrogenase and 3-phosphoglycerate kinase is near equilibrium; (3) the ATP synthesis by the mitochondrial H/sup +/-ATPase occurs unidirectionally (i.e., the reaction is far out of equilibrium); (4) the operative P:O ratio in the intact myocardium under our conditions is significantly less than the canonically accepted value

  2. Hetergeneous tumour response to photodynamic therapy assessed by in vivo localised 31P NMR spectroscopy.

    PubMed Central

    Ceckler, T. L.; Gibson, S. L.; Kennedy, S. D.; Hill, R.; Bryant, R. G.

    1991-01-01

    Photodynamic therapy (PDT) is efficacious in the treatment of small malignant lesions when all cells in the tumour receive sufficient drug, oxygen and light to induce a photodynamic effect capable of complete cytotoxicity. In large tumours, only partial effectiveness is observed presumably because of insufficient light penetration into the tissue. The heterogeneity of the metabolic response in mammary tumours following PDT has been followed in vivo using localised phosphorus NMR spectroscopy. Alterations in nucleoside triphosphates (NTP), inorganic phosphate (Pi) and pH within localised regions of the tumour were monitored over 24-48 h following PDT irradiation of the tumour. Reduction of NTP and increases in Pi were observed at 4-6 h after PDT irradiation in all regions of treated tumours. The uppermost regions of the tumours (those nearest the skin surface and exposed to the greatest light fluence) displayed the greatest and most prolonged reduction of NTP and concomitant increase in Pi resulting in necrosis. The metabolite concentrations in tumour regions located towards the base of the tumour returned a near pre-treatment levels by 24-48 h after irradiation. The ability to follow heterogeneous metabolic responses in situ provides one means to assess the degree of metabolic inhibition which subsequently leads to tumour necrosis. Images Figure 4 PMID:1829953

  3. Unique Backbone-Water Interaction Detected in Sphingomyelin Bilayers with 1H/31P and 1H/13C HETCOR MAS NMR Spectroscopy

    PubMed Central

    Holland, Gregory P.; Alam, Todd M.

    2008-01-01

    Two-dimensional 1H/31P dipolar heteronuclear correlation (HETCOR) magic-angle spinning nuclear magnetic resonance (NMR) is used to investigate the correlation of the lipid headgroup with various intra- and intermolecular proton environments. Cross-polarization NMR techniques involving 31P have not been previously pursued to a great extent in lipid bilayers due to the long 1H-31P distances and high degree of headgroup mobility that averages the dipolar coupling in the liquid crystalline phase. The results presented herein show that this approach is very promising and yields information not readily available with other experimental methods. Of particular interest is the detection of a unique lipid backbone-water intermolecular interaction in egg sphingomyelin (SM) that is not observed in lipids with glycerol backbones like phosphatidylcholines. This backbone-water interaction in SM is probed when a mixing period allowing magnetization exchange between different 1H environments via the nuclear Overhauser effect (NOE) is included in the NMR pulse sequence. The molecular information provided by these 1H/31P dipolar HETCOR experiments with NOE mixing differ from those previously obtained by conventional NOE spectroscopy and heteronuclear NOE spectroscopy NMR experiments. In addition, two-dimensional 1H/13C INEPT HETCOR experiments with NOE mixing support the 1H/31P dipolar HETCOR results and confirm the presence of a H2O environment that has nonvanishing dipolar interactions with the SM backbone. PMID:18390621

  4. 31P NMR spectroscopy of hypertrophied rat heart: effect of graded global ischemia.

    PubMed

    Clarke, K; Sunn, N; Willis, R J

    1989-12-01

    To investigate the cause for the greater susceptibility of hypertrophied hearts to ischemic injury, we determined the interrelations of total work output, contractile function and energy metabolism in isolated, perfused normal and hypertrophied rat hearts subjected to graded global ischemia. Cardiac hypertrophy was induced by giving rats seven daily injections of either triiodothyronine (0.2 mg/kg) or isoproterenol (5 mg/kg). All hearts were perfused at an aortic pressure of 100 mmHg in the isovolumic mode in an NMR spectrometer (7.05 Tesla). Heart rate, developed pressure, and coronary flow were monitored simultaneously with changes in pH, creatine phosphate, ATP and inorganic phosphate. During pre-ischemic perfusion, the total work output (rate-pressure product) of hyperthyroid hearts was 28% higher than that of control hearts, whereas hearts from isoproterenol-treated animals showed no difference. However, when related to unit muscle mass, work was normal in hyperthyroid hearts and 26% lower after isoproterenol. Contractile function per unit myocardium (developed pressure/g wet weight) was lower in the hypertrophied hearts. ATP content was the same in all groups. Creatine phosphate decreased 41% after triiodothyronine and 25% after isoproterenol. Inorganic phosphate levels and intracellular pH were similar in control and isoproterenol-treated rat hearts, but were higher in the hyperthyroid rat hearts. The phosphorylation potential and the free energy change of ATP hydrolysis were lowered by hypertrophy, the levels correlating with the depressed contractile function. At each ischemic flow rate, both work and contractile function per unit myocardium were the same for all hearts, but the relations between flow and phosphorylation potential were different for each type of heart. Thus, at low flow rates, hypertrophied hearts perform the same amount of work and have the same contractile function as control hearts, but with abnormal changes in energy metabolism

  5. Structural and {sup 31}P NMR investigation of Bi(MM'){sub 2}PO{sub 6} statistic solid solutions: Deconvolution of lattice constraints and cationic influences

    SciTech Connect

    Colmont, Marie; Delevoye, Laurent; Ketatni, El Mostafa; Montagne, Lionel; Mentre, Olivier . E-mail: mentre@ensc-lille.fr

    2006-07-15

    Two solid solutions BiM{sub x} Mg{sub (2-x)}PO{sub 6} (with M {sup 2+}=Zn or Cd) have been studied through {sup 31}P MAS NMR. The analysis has been performed on the basis of refined crystal structures through X-ray diffraction and neutron diffraction. The BiZn {sub x} Mg{sub (2-x)}PO{sub 6} does not provide direct evidence for sensitive changes in the phosphorus local symmetry. This result is in good agreement with structural data which show nearly unchanged lattices and atomic separations through the Zn{sup 2+} for Mg{sup 2+} substitution. On the other hand, the Cd{sup 2+} for Mg{sup 2+} substitution behaves differently. Indeed, up to five resonances are observed, each corresponding to one of the five first-cationic neighbour distributions, i.e. 4Mg/0Cd, 3Mg/1Cd, 2Mg/2Cd, 1Mg/3Cd and 0Mg/4Cd. Their intensities match rather well the expected weight for each configuration of the statistical Cd{sup 2+}/Mg{sup 2+} mixed occupancy. The match is further improved when one takes into account the influence of the 2nd cationic sphere that is available from high-field NMR data (18.8 T). Finally, the fine examination of the chemical shift for each resonance versus x allows to de-convolute the mean Z/a {sup 2} effective field into two sub-effects: a lattice constraint-only term and a chemical-only term whose effects are directly quantifiable. - Graphical abstract: First (CdMg){sub 4} cationic sphere influence on the {sup 31}P NMR signal in Bi(Cd,Mg){sub 2}PO{sub 6}. Display Omitted.

  6. Direct Speciation of Phosphorus in Alum-Amended Poultry Litter: Solid-State 31P NMR Investigation

    SciTech Connect

    Hunger, Stefan; Cho, Herman M.; Sims, James T.; Sparks, Donald L.

    2004-02-01

    Amending poultry litter (PL) with aluminum sulfate (alum) has proven to be effective in reducing water-soluble phosphorus (P) in the litter and in runoff from fields that have received PL applications; it has therefore been suggested as a best management practice. Although its effectiveness has been demonstrated on a macroscopic scale in the field, little is known about P speciation in either alumamended or unamended litter. This knowledge is important for the evaluation of the long-term stability and bioavailability of P, which is a necessary prerequisite for the assessment of the sustainability of intensive poultry operations. Both solid state MAS and CP-MAS {sup 31}P NMR as well as {sup 31}P({sup 27}Al) TRAPDOR were used to investigate P speciation in alumamended and unamended PL. The results indicate the presence of a complex mixture of organic and inorganic orthophosphate phases. A calcium phosphate phase, probably a surface precipitate on calcium carbonate, could be identified in both unamended and alum-amended PL, as well as physically bound HPO{sub 4}{sup 2-}. Phosphate associated with Al was found in the alum-amended PL, most probably a mixture of a poorly ordered wavellite and phosphate surface complexes on aluminum hydroxide that had been formed by the hydrolysis of alum. However, a complex mixture of organic and inorganic phosphate species could not be resolved. Phosphate associated with Al comprised on average 40{+-}14% of the total P in alum-amended PL, whereas calcium phosphate phases comprised on average 7{+-}4% in the alum-amended PL and 14{+-}5% in the unamended PL.

  7. Dynamic phosphometabolomic profiling of human tissues and transgenic models by 18O-assisted 31P NMR and mass spectrometry

    PubMed Central

    Nemutlu, Emirhan; Zhang, Song; Gupta, Anu; Juranic, Nenad O.; Macura, Slobodan I.; Terzic, Andre; Jahangir, Arshad

    2012-01-01

    Next-generation screening of disease-related metabolomic phenotypes requires monitoring of both metabolite levels and turnover rates. Stable isotope 18O-assisted 31P nuclear magnetic resonance (NMR) and mass spectrometry uniquely allows simultaneous measurement of phosphometabolite levels and turnover rates in tissue and blood samples. The 18O labeling procedure is based on the incorporation of one 18O into Pi from [18O]H2O with each act of ATP hydrolysis and the distribution of 18O-labeled phosphoryls among phosphate-carrying molecules. This enables simultaneous recording of ATP synthesis and utilization, phosphotransfer fluxes through adenylate kinase, creatine kinase, and glycolytic pathways, as well as mitochondrial substrate shuttle, urea and Krebs cycle activity, glycogen turnover, and intracellular energetic communication. Application of expanded 18O-labeling procedures has revealed significant differences in the dynamics of G-6-P[18O] (glycolysis), G-3-P[18O] (substrate shuttle), and G-1-P[18O] (glycogenolysis) between human and rat atrial myocardium. In human atria, the turnover of G-3-P[18O], which defects are associated with the sudden death syndrome, was significantly higher indicating a greater importance of substrate shuttling to mitochondria. Phosphometabolomic profiling of transgenic hearts deficient in adenylate kinase (AK1−/−), which altered levels and mutations are associated to human diseases, revealed a stress-induced shift in metabolomic profile with increased CrP[18O] and decreased G-1-P[18O] metabolic dynamics. The metabolomic profile of creatine kinase M-CK/ScCKmit−/−-deficient hearts is characterized by a higher G-6-[18O]P turnover rate, G-6-P levels, glycolytic capacity, γ/β-phosphoryl of GTP[18O] turnover, as well as β-[18O]ATP and β-[18O]ADP turnover, indicating altered glycolytic, guanine nucleotide, and adenylate kinase metabolic flux. Thus, 18O-assisted gas chromatography-mass spectrometry and 31P NMR provide a suitable

  8. A chelate-stabilized ruthenium(sigma-pyrrolato) complex: resolving ambiguities in nuclearity and coordination geometry through 1H PGSE and 31P solid-state NMR studies.

    PubMed

    Foucault, Heather M; Bryce, David L; Fogg, Deryn E

    2006-12-11

    Reaction of RuCl2(PPh3)3 with LiNN' (NN' = 2-[(2,6-diisopropylphenyl)imino]pyrrolide) affords a single product, with the empirical formula RuCl[(2,6-iPr2C6H3)N=CHC4H3N](PPh3)2. We identify this species as a sigma-pyrrolato complex, [Ru(NN')(PPh3)2]2(mu-Cl)2 (3b), rather than mononuclear RuCl(NN')(PPh3)2 (3a), on the basis of detailed 1D and 2D NMR characterization in solution and in the solid state. Retention of the chelating, sigma-bound iminopyrrolato unit within 3b, despite the presence of labile (dative) chloride and PPh3 donors, indicates that the chelate effect is sufficient to inhibit sigma --> pi isomerization of 3b to a piano-stool, pi-pyrrolato structure. 2D COSY, SECSY, and J-resolved solid-state 31P NMR experiments confirm that the PPh3 ligands on each metal center are magnetically and crystallographically inequivalent, and 31P CP/MAS NMR experiments reveal the largest 99Ru-31P spin-spin coupling constant (1J(99Ru,31P) = 244 +/- 20 Hz) yet measured. Finally, 31P dipolar-chemical shift spectroscopy is applied to determine benchmark phosphorus chemical shift tensors for phosphine ligands in hexacoordinate ruthenium complexes.

  9. Modeling Ti/Ge Distribution in LiTi2-xGex(PO4)3 NASICON Series by (31)P MAS NMR and First-Principles DFT Calculations.

    PubMed

    Diez-Gómez, Virginia; Arbi, Kamel; Sanz, Jesús

    2016-08-01

    Ti/Ge distribution in rhombohedral LiTi2-xGex(PO4)3 NASICON series has been analyzed by (31)P magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy and first-principles density functional theory (DFT) calculations. Nuclear magnetic resonance is an excellent probe to follow Ti/Ge disorder, as it is sensitive to the atomic scale environment without long-range periodicity requirements. In the samples considered here, PO4 units are surrounded by four Ti/Ge octahedra, and then, five different components ascribed to P(OTi)4, P(OTi)3(OGe), P(OTi)2(OGe)2, P(OTi)(OGe)3, and P(OGe)4 environments are expected in (31)P MAS NMR spectra of R3̅c NASICON samples. However, (31)P MAS NMR spectra of analyzed series display a higher number of signals, suggesting that, although the overall symmetry remains R3̅c, partial substitution causes a local decrement in symmetry. With the aid of first-principles DFT calculations, 10 detected (31)P NMR signals have been assigned to different Ti4-nGen arrangements in the R3 subgroup symmetry. In this assignment, the influence of octahedra of the same or different R2(PO4)3 structural units has been considered. The influence of bond distances, angles and atom charges on (31)P NMR chemical shieldings has been discussed. Simulation of the LiTi2-xGex(PO4)3 series suggests that detection of 10 P environments is mainly due to the existence of two oxygen types, O1 and O2, whose charges are differently affected by Ge and Ti occupation of octahedra. From the quantitative analysis of detected components, a random Ti/Ge distribution has been deduced in next nearest neighbor (NNN) sites that surround tetrahedral PO4 units. This random distribution was supported by XRD data displaying Vegard's law.

  10. Dynamic structures of intact chicken erythrocyte chromatins as studied by 1H-31P cross-polarization NMR.

    PubMed Central

    Akutsu, H; Nishimoto, S; Kyogoku, Y

    1994-01-01

    The dynamic properties of DNA in intact chicken erythrocyte cells, nuclei, nondigested chromatins, digested soluble chromatins, H1, H5-depleted soluble chromatins and nucleosome cores were investigated by means of single-pulse and 1H-31P cross-polarization NMR. The temperature dependence of the phosphorus chemical shift anisotropy was identical for the former three in the presence of 3 mM MgCl2, suggesting that the local higher order structure is identical for these chromatins. The intrinsic phosphorus chemical shift anisotropy of the nucleosome cores was -159 ppm. The chemical shift anisotropy of DNA in the chromatins can be further averaged by the motion of the linker DNA. The spin-lattice relaxation time in the rotating frame of the proton spins (T1p) of the nondigested chromatins was measured at various locking fields. The result was analyzed on the assumption of the isotropic motion to get a rough value of the correlation time of the motion efficient for the relaxation, which was eventually ascribed to the segmental motion of the linker DNA with restricted amplitude. The 30 nm filament structure induced by NaCl was shown to be dynamically different from that induced by MgCl2. Side-by-side compaction of 30-nm filaments was suggested to be induced in the MgCl2 concentration range higher than 0.3 mM. Biological significance of the dynamic structure was discussed in connection with the results obtained. PMID:7948693

  11. CO2 induced acute respiratory acidosis and brain tissue intracellular pH: a 31P NMR study in swine.

    PubMed

    Martoft, L; Stødkilde-Jørgensen, H; Forslid, A; Pedersen, H D; Jørgensen, P F

    2003-07-01

    High concentration carbon dioxide (CO(2)) is used to promote pre-slaughter anaesthesia in swine and poultry, as well as short-lasting surgical anaesthesia and euthanasia in laboratory animals. Questions related to animal welfare have been raised, as CO(2) anaesthesia does not set in momentarily. Carbon dioxide promotes anaesthesia by lowering the intracellular pH in the brain cells, but the dynamics of the changes in response to a high concentration of CO(2) is not known. Based on (31)P NMR spectroscopy, we describe CO(2)-induced changes in intracellular pH in the brains of five pigs inhaling 90% CO(2) in ambient air for a period of 60 s, and compare the results to changes in arterial blood pH, P(CO2), O(2) saturation and HCO(3)(-) concentration. The intracellular pH paralleled the arterial pH and P(CO2) during inhalation of CO(2); and it is suggested that the acute reaction to CO(2) inhalation mainly reflects respiratory acidosis, and not metabolic regulation as for example transmembrane fluxes of H(+)/HCO(3)(-). The intracellular pH decreased to approximately 6.7 within the 60 s inhalation period, and the situation was metabolically reversible after the end of CO(2) inhalation. The fast decrease in intracellular pH supports the conclusion that high concentration CO(2) leads to anaesthesia soon after the start of inhalation. PMID:12869287

  12. Influence of temperature on 31P NMR chemical shifts of phospholipids and their metabolites I. In chloroform-methanol-water.

    PubMed

    Estrada, Rosendo; Stolowich, Neal; Yappert, M Cecilia

    2008-09-01

    Spectral overlap of (31)P NMR resonances and the lack of reproducibility in chemical shifts corresponding to phospholipids in organic solvents challenge the accuracy of band assignments and quantification. To alleviate these problems, the use of temperature coefficients is proposed. Changes in temperature enable the resolution of overlapped resonances and provide a facile approach for the computation of temperature coefficients. The coefficients were evaluated for various glycero- and sphingo-phospholipids. Their values suggest that differences in H-bonding between the phosphate and the head groups are responsible for the changes of chemical shift with temperature. Among parent phospholipids, and in addition to sphingomyelin, the smallest temperature coefficient values (closest to zero) were observed for phosphatidylcholine, phosphatidylglycerol, dihydrosphingomyelin, and cardiolipin. The highest values were exhibited by phospholipids with protonated head groups, such as phosphatidylserine and phosphatidylethanolamine. The lowest and, in fact, negative values were measured for phospholipids with an exposed phosphate group: phosphatidic acid, ceramide-1-phosphate, and dihydroceramide-1-phosphate. Diacyl, alkyl-acyl, and alkenyl-acyl phospholipids with the same head group exhibited comparable coefficients but differed slightly in chemical shifts. Compared to their parent glycerophospholipids, all lyso analogs had greater temperature coefficients, possibly due to the presence of an extra OH capable of forming a H-bond with the phosphate group. PMID:18534182

  13. Detailed Chemical Composition of Condensed Tannins via Quantitative (31)P NMR and HSQC Analyses: Acacia catechu, Schinopsis balansae, and Acacia mearnsii.

    PubMed

    Crestini, Claudia; Lange, Heiko; Bianchetti, Giulia

    2016-09-23

    The chemical composition of Acacia catechu, Schinopsis balansae, and Acacia mearnsii proanthocyanidins has been determined using a novel analytical approach that rests on the concerted use of quantitative (31)P NMR and two-dimensional heteronuclear NMR spectroscopy. This approach has offered significant detailed information regarding the structure and purity of these complex and often elusive proanthocyanidins. More specifically, rings A, B, and C of their flavan-3-ol units show well-defined and resolved absorbance regions in both the quantitative (31)P NMR and HSQC spectra. By integrating each of these regions in the (31)P NMR spectra, it is possible to identify the oxygenation patterns of the flavan-3-ol units. At the same time it is possible to acquire a fingerprint of the proanthocyanidin sample and evaluate its purity via the HSQC information. This analytical approach is suitable for both the purified natural product proanthocyanidins and their commercial analogues. Overall, this effort demonstrates the power of the concerted use of these two NMR techniques for the structural elucidation of natural products containing labile hydroxy protons and a carbon framework that can be traced out via HSQC. PMID:27551744

  14. Ionization behavior of polyphosphoinositides determined via the preparation of pH titration curves using solid-state 31P NMR.

    PubMed

    Graber, Zachary T; Kooijman, Edgar E

    2013-01-01

    Detailed knowledge of the degree of ionization of lipid titratable groups is important for the evaluation of protein-lipid and lipid-lipid interactions. The degree of ionization is commonly evaluated by acid-base titration, but for lipids localized in a multicomponent membrane interface this is not a suitable technique. For phosphomonoester-containing lipids such as the polyphosphoinositides, phosphatidic acid, and ceramide-1-phosphate, this is more conveniently accomplished by (31)P NMR. Here, we describe a solid-state (31)P NMR procedure to construct pH titration curves to determine the degree of ionization of phosphomonoester groups in polyphosphoinositides. This procedure can also be used, with suitable sample preparation conditions, for other important signaling lipids. Access to a solid-state, i.e., magic angle spinning, capable NMR spectrometer is assumed. The procedures described here are valid for a Bruker instrument, but can be adapted for other spectrometers as needed.

  15. ¹¹³Cd NMR experiments reveal an unusual metal cluster in the solution structure of the yeast splicing protein Bud31p.

    PubMed

    van Roon, Anne-Marie M; Yang, Ji-Chun; Mathieu, Daniel; Bermel, Wolfgang; Nagai, Kiyoshi; Neuhaus, David

    2015-04-13

    Establishing the binding topology of structural zinc ions in proteins is an essential part of their structure determination by NMR spectroscopy. Using (113)Cd NMR experiments with (113)Cd-substituted samples is a useful approach but has previously been limited mainly to very small protein domains. Here we used (113)Cd NMR spectroscopy during structure determination of Bud31p, a 157-residue yeast protein containing an unusual Zn3Cys9 cluster, demonstrating that recent hardware developments make this approach feasible for significantly larger systems.

  16. Monitoring biodegradation of poly(butylene sebacate) by Gel Permeation Chromatography, (1)H-NMR and (31)P-NMR techniques.

    PubMed

    Siotto, Michela; Zoia, Luca; Tosin, Maurizio; Degli Innocenti, Francesco; Orlandi, Marco; Mezzanotte, Valeria

    2013-02-15

    The increasing use of new generation plastics has been accompanied by the development of standard methods for studying their biodegradability. Generally, test methods are based on the measurement of CO(2) production, i.e. the mineralization degree of the tested materials. However, in order to describe the biodegradation process, the determination of the residual amount of tested material which remains in the environment and its chemical characterization can be very important. In this study, the biodegradation in soil of a model polyester (poly(butylene sebacate)) was monitored. Gel Permeation Chromatography and Nuclear Magnetic Resonance ((31)P-NMR and (1)H-NMR) were used in order to obtain information about the polyester structure and the possible by-products that can be found in soil during and at the end of the incubation. The polyester mineralization (i.e. the CO(2) production) was tested according to ASTM 5988 standard method for 245 days. When the polyester mineralization was about 21% and 37% (after 78 and 140 days of incubation) and at the end of the process (63% of mineralization, 100% if compared to the cellulose used as reference material), the soil was extracted with chloroform (solvent of the tested substance) and the extracts were analyzed using GPC and NMR acquisitions. The analytical acquisitions showed high molecular weight polyester in soil during the incubation (78 and 140 days): the polyester concentration decreased but its structure remained almost the same with a slow decreasing in molecular weight. At the end of the test (245 days) no film of the polyester could be extracted from the soil: NMR acquisitions and GPC analyses of the extracts suggested a strong degraded structure of the residual polyester. Even if at the end of the process only 63% of carbon had been lost by mineralization, the whole of the added polyester seems to have disappeared after about eight months of incubation, suggesting substantial biomass formation.

  17. Organophosphates in agrogray soils with periodic water logging according to the data of 31P NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Kovalev, I. V.; Kovaleva, N. O.

    2011-01-01

    The composition of organic phosphorus compounds was studied using the 31P NMR spectroscopy method in agrogray soils with periodic water logging. The phosphorus content was determined by the specific difference between the hydrological and the redox regimes of these soils. The phosphorus of the organic compounds in the agrogray soils with contrasting water regimes is composed mostly of phosphoric monoesters and diesters, including nucleic and teichoic acids. The relative distribution of the monoesters and inorganic orthophosphates is shown depending on the climate and the soil's position in the relief. The area of the monoester peaks increases by two times and that of the mineral orthophosphate decreases by six times in the agro-gray soils of Bryansk opolie with an optimal regime of moistening and evaporation in comparison with the agro-gray gleyed soils of Kolomna opolie. As the degree of the soil hydromorphism in the sequence of deeply gleyed soils and gleyic soils increased, the portion of monoesters decreased. Favorable conditions for the microbial activity are formed in soils with a contrasting redox regime, and this is expressed in the accumulation of labile diesters. Inverse relationships were found between the distributions of the mono- and diesters in iron-manganic nodules and in the soils enclosing them; this was caused by the different mechanisms of the stabilization of the stable and labile phosphorus containing compounds. A high percentage of mineral orthophosphate in the nodules allows assuming the presence of chemisorbed orthophosphate ions in organomineral phosphate-metal-humus complexes. The transformation of iron-manganic nodules under the influence of drying demonstrates the more direct participation of microorganisms in the nodules' formation than the contribution of the physicochemical processes.

  18. Assessing the phosphate distribution in bioactive phosphosilicate glasses by 31P solid-state NMR and molecular dynamics simulations.

    PubMed

    Stevensson, Baltzar; Mathew, Renny; Edén, Mattias

    2014-07-24

    Melt-derived bioactive phosphosilicate glasses are widely utilized as bone-grafting materials for various surgical applications. However, the insight into their structural features over a medium-range scale up to ∼ 1 nm remains limited. We present a comprehensive assessment of the spatial distribution of phosphate groups across the structures of 11 Na2O-CaO-SiO2-P2O5 glasses that encompass both bioactive and nonbioactive compositions, with the P contents and silicate network connectivities varied independently. Both parameters are known to strongly influence the bioactivity of the glass in vitro. The phosphate distribution was investigated by double-quantum (31)P nuclear magnetic resonance (NMR) experiments under magic-angle spinning (MAS) conditions and by molecular dynamics (MD) simulations. The details of the phosphate-ion dispersion were probed by evaluating the MD-derived glass models against various scenarios of randomly distributed, as well as clustered, phosphate groups. From comparisons of the P-P interatomic-distance spreads and the statistics of small phosphate clusters assessed for variable cutoff radii, we conclude that the spatial arrangement of the P atoms in phosphosilicate glasses is well-approximated by a statistical distribution, particularly across a short-range scale of ≤ 450 pm. The primary distinction is reflected in slightly closer P-P interatomic contacts in the MD-derived structures over the distance span of 450-600 pm relative to that of randomly distributed phosphate groups. The nature of the phosphate-ion dispersion remains independent of the silicate network polymerization and nearly independent of the P content of the glass throughout our explored parameter space of 1-6 mol % P2O5 and silicate network connectivities up to 2.9.

  19. {sup 31}P NMR study of the complexation of TBP with lanthanides and actinides in solution and in a clay matrix

    SciTech Connect

    Hartzell, C.J.

    1994-07-24

    Goal was to use NMR to study TBP/lanthanide complexes in the interlayer or on edge sites of clays. Work in this laboratory yielded details of the complexation of Eu(NO{sub 3}){sub 3} and Pr(NO{sub 3}){sub 3} with TBP in hexane solution; this information is crucial to interpretation of results of NMR studies of the complexes exchanged into clays. The solution {sup 31}P-chemical shift values were improved by repeating the studies on the lanthanide salts dissolved directly into neat TBP. NMR studies of these neat solutions of the Eu(NO{sub 3}){sub 3}{lg_bullet}3TBP-complex and the Pr(NO{sub 3}){sub 3}{lg_bullet}3TBP-complex show that the {sup 31}P chemical shift remains relatively constant for TBP: lanthanide ratios below 3: 1. At higher ratios, the chemical shift approaches that of free TBP, indicating rapid exchange of TBP between the free and complexed state. Exchange of these complexes into the clay hectorite yielded discrete {sup 31}P-NMR signals for the Eu{lg_bullet}TBP complex at -190 ppm and free TBP at -6 ppm. Adsorption of the Pr{lg_bullet}TBP complex yielded broad signals at 76 ppm for the complex and -6 ppm for free TBP. There was no evidence of exchange between the incorporated complex and the free TBP.

  20. In vivo 31P NMR OSIRIS of bioenergetic changes in rabbit kidneys during and after ischaemia: effect of pretreatment with an indeno-indole compound.

    PubMed

    Sørensen, V; Jonsson, O; Pettersson, S; Scherstén, T; Soussi, B

    1998-04-01

    Changes in energy phosphates of rabbit kidneys subjected to ischaemia-reperfusion have been measured in vivo with volume selective 31P NMR spectroscopy. The effects of pretreatment with a new lipid peroxidation inhibitor (indeno-indol derivate--code name H290/51) on the bioenergetic changes were analysed. The left kidney was moved to a subcutaneous pocket to facilitate exact positioning over the surface coil. A 1H NMR image was acquired and a 3.5-mL cube selected for 31P NMR spectra. 31P NMR spectra were recorded before occlusion of the left renal artery, during 1 h of ischaemia and 2 hours of reperfusion. Ischaemia induced drastic changes in the levels of inorganic phosphates and ATP as well as intracellular acidosis. A normalization was observed during reperfusion. Two hours after reperfusion significantly higher values for beta-ATP/Pi and intracellular pH were recorded in the animals pretreated with H290/51. The present technique allows quantitative analyses of changes in kidney bioenergetics in vivo during different experimental conditions. The importance of ischaemia-reperfusion induced lipid peroxidation for mitochondrial function is emphasized.

  1. Effects of pH and cholesterol on DMPA membranes: a solid state 2H- and 31P-NMR study.

    PubMed Central

    Pott, T; Maillet, J C; Dufourc, E J

    1995-01-01

    The effect of pH and cholesterol on the dimyristoylphosphatidic acid (DMPA) model membrane system has been investigated by solid state 2H- and 31P-NMR. It has been shown that each of the three protonation states of the DMPA molecule corresponds to a 31P-NMR powder pattern with characteristic delta sigma values; this implies additionally that the proton exchange on the membrane surface is slow on the NMR time scale (millisecond range). Under these conditions, the 2H-labeled lipid chains sense only one magnetic environment, indicating that the three spectra detected by 31P-NMR are related to charge-dependent local dynamics or orientations of the phosphate headgroup or both. Chain ordering in the fluid phase is also found to depend weakly on the charge at the interface. In addition, it has also been found that the first pK of the DMPA membrane is modified by changes in the lipid lateral packing (gel or fluid phases or in the presence of cholesterol) in contrast to the second pK. The incorporation of 30 mol% cholesterol affects the phosphatidic acid bilayer in a way similar to what has been reported for phosphatidylcholine/cholesterol membranes, but to an extent comparable to 10-20 mol % sterol in phosphatidylcholines. However, the orientation and molecular order parameter of cholesterol in DMPA are similar to those found in dimyristoylphosphatidylcholine. PMID:8580333

  2. Delineation of conformational preferences in human salivary statherin by 1H, 31P NMR and CD studies: sequential assignment and structure-function correlations.

    PubMed

    Naganagowda, G A; Gururaja, T L; Levine, M J

    1998-08-01

    Membrane-induced solution structure of human salivary statherin, a 43 amino acid residue acidic phosphoprotein, has been investigated by two-dimensional proton nuclear magnetic resonance (2D 1H NMR) spectroscopy. NMR assignments and structural analysis of this phosphoprotein was accomplished by analyzing the pattern of sequential and medium range NOEs, alphaCH chemical shift perturbations and deuterium exchange measurements of the amide proton resonances. The NMR data revealed three distinct structural motifs in the molecule: (1) an alpha-helical structure at the N-terminal domain comprising Asp1-Tyr16, (2) a polyproline type II (PPII) conformation predominantly occurring at the middle proline-rich domain spanning Gly19-Gln35, and (3) a 3(10)-helical structure at the C-terminal Pro36-Phe43 sequence. Presence of a few weak dalphaN(i,i+2) NOEs suggests that N-terminus also possesses minor population of 3(10)-helical conformation. Of the three secondary structural elements, helical structure formed by the N-terminal residues, Asp1-Ile11 appears to be more rigid as observed by the relatively very slow exchange of amide hydrogens of Glu5-Ile11. 31P NMR experiments clearly indicated that N-terminal domain of statherin exists mainly in disordered state in water whereas, upon addition of structure stabilizing co-solvent, 2,2,2-trifluorethanol (TFE), it showed a strong propensity for helical conformation. Calcium ion interaction studies suggested that the disordered N-terminal region encompassing the two vicinal phosphoserines is essential for the binding of calcium ions in vivo. Results from the circular dichroism (CD) experiments were found to be consistent with and complimentary to the NMR data and provided an evidence that non-aqueous environment such as TFE, could induce the protein to fold into helical conformation. The findings that the statherin possesses blended solvent sensitive secondary structural elements and the requirement of non-structured N-terminal region

  3. Vacuolar glyphosate-sequestration correlates with glyphosate resistance in ryegrass (Lolium spp.) from Australia, South America, and Europe: a 31P NMR investigation.

    PubMed

    Ge, Xia; d'Avignon, D André; Ackerman, Joseph J H; Collavo, Alberto; Sattin, Maurizio; Ostrander, Elizabeth L; Hall, Erin L; Sammons, R Douglas; Preston, Christopher

    2012-02-01

    Lolium spp., ryegrass, variants from Australia, Brazil, Chile, and Italy showing differing levels of glyphosate resistance were examined by (31)P NMR. Extents of glyphosate (i) resistance (LD(50)), (ii) inhibition of 5-enopyruvyl-shikimate-3-phosphate synthase (EPSPS) activity (IC(50)), and (iii) translocation were quantified for glyphosate-resistant (GR) and glyphosate-sensitive (GS) Lolium multiflorum Lam. variants from Chile and Brazil. For comparison, LD(50) and IC(50) data for Lolium rigidum Gaudin variants from Italy were also analyzed. All variants showed similar cellular uptake of glyphosate by (31)P NMR. All GR variants showed glyphosate sequestration within the cell vacuole, whereas there was minimal or no vacuole sequestration in the GS variants. The extent of vacuole sequestration correlated qualitatively with the level of resistance. Previous (31)P NMR studies of horseweed ( Conyza canadensis (L.) Cronquist) revealed that glyphosate sequestration imparted glyphosate resistance. Data presented herein suggest that glyphosate vacuolar sequestration is strongly contributing, if not the major contributing, resistance mechanism in ryegrass as well.

  4. Probing the interface of core shell particles of GaPO 4 and AlPO 4 by 31P MAS NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Kulshreshtha, S. K.; Jayakumar, O. D.; Vishwanadh, B.; Sudarsan, V.

    2011-02-01

    Hexagonal GaPO 4, pseudo-hexagonal AlPO 4 and the core shell particles of these phosphates have been prepared in ethylene glycol medium at 180 °C, followed by annealing at 900 °C for 24 h and investigated by powder X-ray diffraction and 31P Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) techniques. The 31P NMR studies of these core shell particles showed a multi-component NMR pattern consisting of five peaks originating due to the distinct structural configurations formed by the varying number of Al 3+ and Ga 3+ as the next nearest neighbors around the probe 31P nuclei of the PO 4 tetrahedron. Existence of different PO 4 structural units with varying number of Al 3+ and Ga 3+ as its next nearest neighbors around P nucleus at the interface of the core shell particles has been confirmed. These results clearly indicate the bond formation at the interface between the core and shell material for these particles.

  5. 31P NMR relaxation of cortical bone mineral at multiple magnetic field strengths and levels of demineralization.

    PubMed

    Seifert, Alan C; Wright, Alexander C; Wehrli, Suzanne L; Ong, Henry H; Li, Cheng; Wehrli, Felix W

    2013-09-01

    Recent work has shown that solid-state (1) H and (31) P MRI can provide detailed insight into bone matrix and mineral properties, thereby potentially enabling differentiation of osteoporosis from osteomalacia. However, (31) P MRI of bone mineral is hampered by unfavorable relaxation properties. Hence, accurate knowledge of these properties is critical to optimizing MRI of bone phosphorus. In this work, (31) P MRI signal-to-noise ratio (SNR) was predicted on the basis of T1 and T2 * (effective transverse relaxation time) measured in lamb bone at six field strengths (1.5-11.7 T) and subsequently verified by 3D ultra-short echo-time and zero echo-time imaging. Further, T1 was measured in deuterium-exchanged bone and partially demineralized bone. (31) P T2 * was found to decrease from 220.3 ± 4.3 µs to 98.0 ± 1.4 µs from 1.5 to 11.7 T, and T1 to increase from 12.8 ± 0.5 s to 97.3 ± 6.4 s. Deuteron substitution of exchangeable water showed that 76% of the (31) P longitudinal relaxation rate is due to (1) H-(31) P dipolar interactions. Lastly, hypomineralization was found to decrease T1, which may have implications for (31) P MRI based mineralization density quantification. Despite the steep decrease in the T2 */T1 ratio, SNR should increase with field strength as B0 (0.4) for sample-dominated noise and as B0 (1.1) for coil-dominated noise. This was confirmed by imaging experiments. PMID:23505120

  6. Molecular level investigations of phosphate sorption on corundum (α-Al2O3) by 31P solid state NMR, ATR-FTIR and quantum chemical calculation

    NASA Astrophysics Data System (ADS)

    Li, Wei; Pierre-Louis, Andro-Marc; Kwon, Kideok D.; Kubicki, James D.; Strongin, Daniel R.; Phillips, Brian L.

    2013-04-01

    Phosphate sorption at the corundum (α-Al2O3)/water interface was investigated as a function of phosphate concentration (0.1-1 mM) and pH (3-11) by 31P solid state NMR spectroscopy, ATR-FTIR, and quantum chemical calculation. The 31P NMR spectra indicate that under these experimental conditions phosphate adsorbs onto corundum mainly as inner-sphere complexes that yield a peak at δP = -2.8 ppm with full width at half maximum (FWHM) of 9.2 ppm, with a small amount aluminum phosphate surface precipitates as suggested by an NMR signal observed from δP = -12 to -20 ppm. We employed 31P{27Al} rotational echo adiabatic passage double resonance (REAPDOR) to further analyze the phosphate adsorption samples prepared at pH 5 and 9 in order to determine the phosphate/Al coordination. To aid interpretation of the NMR data, a series of bidentate and monodentate structural models of phosphate adsorbed on corundum (0 0 1) and (0 1 2) surfaces were calculated using density function theory (DFT). By comparing the experimental REAPDOR curves and those simulated from these models, we can assign the dominant peaks to bidentate binuclear surface complexes. Formation of bidentate binuclear surface complexes is supported by the ATR/FTIR spectra combined with DFT calculation, which further suggests a mixture of non-protonated bidentate and mono-protonated bidentate surface complexes on the corundum surface at pH 5. At pH 9, both NMR and ATR/FTIR indicate the formation of bidentate surface complexes on corundum surface.

  7. Intra- and extracellular pH of the brain in vivo studied by 31P-NMR during hyper- and hypocapnia.

    PubMed

    Portman, M A; Lassen, N A; Cooper, T G; Sills, A M; Potchen, E J

    1991-12-01

    Studies were performed to determine the pH relationships among the extracellular, intracellular, and arterial blood compartments in the brain in vivo. Resolution of the extracellular monophosphate resonance peak from the intracellular peak in 31P nuclear magnetic resonance (NMR) spectra of sheep brain with the calvarium intact enabled pH measurement in these respective compartments. Sheep were then subjected to both hyper- and hypoventilation, which resulted in a wide range of arterial PCO2 and pH values. Linear regression analysis of pH in these compartments yielded slopes of 0.56 +/- 0.05 for extracellular pH (pHe) vs. arterial pH, 0.43 +/- 0.078 for intracellular pH (pHi) vs. pHe, and 0.23 +/- 0.056 for pHi vs. arterial pH. These data indicate that CO2 buffering capacity is different and decreases from the intracellular to extracellular to arterial blood compartments. Separation of the extracellular space from the vascular space may be a function of the blood-brain barrier, which contributes to the buffering capability of the extracellular compartment. A marked decrease in the pH gradient between the extracellular and intracellular space occurs during hypercarbia and may influence mechanisms of central respiratory control.

  8. Quantitative NMR Analysis of Partially Substituted Biodiesel Glycerols

    SciTech Connect

    Nagy, M.; Alleman, T. L.; Dyer, T.; Ragauskas, A. J.

    2009-01-01

    Phosphitylation of hydroxyl groups in biodiesel samples with 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane followed by 31P-NMR analysis provides a rapid quantitative analytical technique for the determination of substitution patterns on partially esterified glycerols. The unique 31P-NMR chemical shift data was established with a series mono and di-substituted fatty acid esters of glycerol and then utilized to characterize an industrial sample of partially processed biodiesel.

  9. Modeling Ti/Ge Distribution in LiTi2-xGex(PO4)3 NASICON Series by (31)P MAS NMR and First-Principles DFT Calculations.

    PubMed

    Diez-Gómez, Virginia; Arbi, Kamel; Sanz, Jesús

    2016-08-01

    Ti/Ge distribution in rhombohedral LiTi2-xGex(PO4)3 NASICON series has been analyzed by (31)P magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy and first-principles density functional theory (DFT) calculations. Nuclear magnetic resonance is an excellent probe to follow Ti/Ge disorder, as it is sensitive to the atomic scale environment without long-range periodicity requirements. In the samples considered here, PO4 units are surrounded by four Ti/Ge octahedra, and then, five different components ascribed to P(OTi)4, P(OTi)3(OGe), P(OTi)2(OGe)2, P(OTi)(OGe)3, and P(OGe)4 environments are expected in (31)P MAS NMR spectra of R3̅c NASICON samples. However, (31)P MAS NMR spectra of analyzed series display a higher number of signals, suggesting that, although the overall symmetry remains R3̅c, partial substitution causes a local decrement in symmetry. With the aid of first-principles DFT calculations, 10 detected (31)P NMR signals have been assigned to different Ti4-nGen arrangements in the R3 subgroup symmetry. In this assignment, the influence of octahedra of the same or different R2(PO4)3 structural units has been considered. The influence of bond distances, angles and atom charges on (31)P NMR chemical shieldings has been discussed. Simulation of the LiTi2-xGex(PO4)3 series suggests that detection of 10 P environments is mainly due to the existence of two oxygen types, O1 and O2, whose charges are differently affected by Ge and Ti occupation of octahedra. From the quantitative analysis of detected components, a random Ti/Ge distribution has been deduced in next nearest neighbor (NNN) sites that surround tetrahedral PO4 units. This random distribution was supported by XRD data displaying Vegard's law. PMID:27373306

  10. Hepatic lipid profiling of deer mice fed ethanol using {sup 1}H and {sup 31}P NMR spectroscopy: A dose-dependent subchronic study

    SciTech Connect

    Fernando, Harshica; Bhopale, Kamlesh K.; Boor, Paul J.; Ansari, G.A. Shakeel; Kaphalia, Bhupendra S.

    2012-11-01

    Chronic alcohol abuse is a 2nd major cause of liver disease resulting in significant morbidity and mortality. Alcoholic liver disease (ALD) is characterized by a wide spectrum of pathologies starting from fat accumulation (steatosis) in early reversible stage to inflammation with or without fibrosis and cirrhosis in later irreversible stages. Previously, we reported significant steatosis in the livers of hepatic alcohol dehydrogenase (ADH)-deficient (ADH{sup −}) vs. hepatic ADH-normal (ADH{sup +}) deer mice fed 4% ethanol daily for 2 months [Bhopale et al., 2006, Alcohol 39, 179–188]. However, ADH{sup −} deer mice fed 4% ethanol also showed a significant mortality. Therefore, a dose-dependent study was conducted to understand the mechanism and identify lipid(s) involved in the development of ethanol-induced fatty liver. ADH{sup −} and ADH{sup +} deer mice fed 1, 2 or 3.5% ethanol daily for 2 months and fatty infiltration in the livers were evaluated by histology and by measuring dry weights of extracted lipids. Lipid metabolomic changes in extracted lipids were determined by proton ({sup 1}H) and {sup 31}phosphorus ({sup 31}P) nuclear magnetic resonance (NMR) spectroscopy. The NMR data was analyzed by hierarchical clustering (HC) and principle component analysis (PCA) for pattern recognition. Extensive vacuolization by histology and significantly increased dry weights of total lipids found only in the livers of ADH{sup −} deer mice fed 3.5% ethanol vs. pair-fed controls suggest a dose-dependent formation of fatty liver in ADH{sup −} deer mouse model. Analysis of NMR data of ADH{sup −} deer mice fed 3.5% ethanol vs. pair-fed controls shows increases for total cholesterol, esterified cholesterol, fatty acid methyl esters (FAMEs), triacylglycerides and unsaturation, and decreases for free cholesterol, phospholipids and allylic and diallylic protons. Certain classes of neutral lipids (cholesterol esters, fatty acyl chain (-COCH{sub 2}-) and FAMEs) were

  11. Phosphatidylinositol-specific phospholipase C from Bacillus cereus combines intrinsic phosphotransferase and cyclic phosphodiesterase activities: A sup 31 P NMR study

    SciTech Connect

    Shashidhar, M.S.; Kuppe, A. ); Volwerk, J.J.; Griffith, O.H.

    1990-09-04

    The inositol phosphate products formed during the cleavage of phosphatidylinositol by phosphatidylinositol-specific phospholipase C from Bacillus cereus were analyzed by {sup 31}P NMR. {sup 31}P NMR spectroscopy can distinguish between the inositol phosphate species and phosphatidylinositol. Chemical shift values (with reference to phosphoric acid) observed are {minus}0.41, 3.62, 4.45, and 16.30 ppm for phosphatidylinositol, myo-inositol 1-monophosphate, myo-inositol 2-monophosphate, and myo-inositol 1,2-cyclic monophosphate, respectively. It is shown that under a variety of experimental conditions this phospholipase C cleaves phosphatidylinositol via an intramolecular phosphotransfer reaction producing diacylglycerol and D-myo-inositol 1,2-cyclic monophosphate. The authors also report the new and unexpected observation that the phosphatidylinositol-specific phospholipase C from B. cereus is able to hydrolyze the inositol cyclic phosphate to form D-myo-inositol 1-monophosphate. The enzyme, therefore, possesses phosphotransferase and cyclic phosphodiesterase activities. The second reaction requires thousandfold higher enzyme concentrations to be observed by {sup 31}P NMR. This reaction was shown to be regiospecific in that only the 1-phosphate was produced and stereospecific in that only D-myo-inositol 1,2-cyclic monophosphate was hydrolyzed. Inhibition with a monoclonal antibody specific for the B.cereus phospholipase C showed that the cyclic phosphodiesterase activity is intrinsic to the bacterial enzyme. They propose a two-step mechanism for the phosphatidyl-inositol-specific phospholipase C from B. cereus involving sequential phosphotransferase and cyclic phosphodiesterase activities. This mechanism bears a resemblance to the well-known two-step mechanism of pancreatic ribonuclease, RNase A.

  12. Characteristics and assessment of biogenic phosphorus in sediments from the multi-polluted Haihe River, China, using phosphorus fractionation and phosphorus-31 nuclear magnetic resonance (31P-NMR)

    NASA Astrophysics Data System (ADS)

    Zhang, W. Q.; Zhang, H.; Tang, W. Z.; Shan, B. Q.

    2013-10-01

    We studied the phosphorus (P) pollution, as described by concentrations, distribution and transformation potential, of sediments of the water scarce and heavily polluted Fuyang River, a tributary of the Haihe River, using P fractionation and phosphorus-31 nuclear magnetic resonance (31P-NMR).The sediments of the Fuyang River accumulate significant amounts of inorganic phosphorus (Pi) and organic phosphorus (Po) from industrial and domestic wastewater and agricultural non-point pollution. In terms of their contribution to total phosphorus, the rank order of the P fractions was as follows: H2SO4-P > NaOH-Pi > Res-P > NaOH-Po > KCl-P and their average relative proportions were 69.7:47.5:15.9:2.9:1.0 (the proportion was based on the average proportion of the KCl-P). Seven P compounds were detected by the 31P-NMR analysis. Orthophosphate (Ortho-P: 45.2-92.4%) and orthophosphate monoesters (mono-P: 6.6-45.7%) were the dominant forms. Smaller amounts of pyrophosphates (pyro-P: 0.1-6.6%), deoxyribonucleic acid (DNA-P: 0.3-3.9%), phosphonates (phon-P: 0-3.3%), phospholipids (lipids-P: 0-2.7%) and polyphosphate (poly-P: 0-0.04%) were observed in the sediments. Results of P fractionation and 31P-NMR analysis showed that 35% of Pi was labile P, including KCl-P and NaOH-Pi (Fe-P and Al-P). Biogenic-P accounted for 24% of P in the sediments. Analysis of the relationships between P species and water quality indicated that the Po compounds would mineralize to form ortho-P and would be potentially bioavailable for recycling to surface water, supporting further growth of phytoplankton and leading to algal blooms.

  13. Combined (Super 31)P and (Super 1)H NMR Experiments in the Structural Elucidation of Polynuclear Thiolate Complexes

    ERIC Educational Resources Information Center

    Cerrada, Elena; Laguna, Mariano

    2005-01-01

    A facile synthesis of two gold(I) complexes with 1,2-benzenedithiolate ligand and two different bidentate phosphines are described. A detailed sequence of NMR experiments is suggested to determine the structure of the compounds.

  14. Hydration behaviour of POPC/C(12)-Bet mixtures investigated by sorption gravimetry, (31)P NMR spectroscopy and X-ray diffraction.

    PubMed

    Pfeiffer, H; Weichert, H; Klose, G; Heremans, K

    2012-02-01

    The hydration behaviour of mixtures of the zwitterionic phospholipid 1-palmitoyl-2-oleolyl-sn-glycero-3-phosphocholine (POPC) and the zwitterionic surfactant N,N-dimethyl-N-dodecyl-betain (C(12)-Bet) was investigated by sorption gravimetry, solid-state (31)P NMR-spectroscopy and small angle X-ray diffraction (SAXD). Negative excess hydration (dehydration) was found for almost all hydration degrees investigated. This behaviour is explained by the formation of an inner salt between the dipoles of phospholipid and surfactant headgroups that show a reverse sequence of partial charges with respect to the hydrocarbon backbone. The formation of an inner-salt most probably reduces potential water binding sites. Moreover, NMR data suggest that the incorporation of the zwitterionic surfactant into the phospholipid membrane is correlated with reorientation of the phosphate axis towards the membrane director as well as with reduced lateral and wobbling diffusion. PMID:22285958

  15. Trimethylphosphine-Assisted Surface Fingerprinting of Metal Oxide Nanoparticle by (31)P Solid-State NMR: A Zinc Oxide Case Study.

    PubMed

    Peng, Yung-Kang; Ye, Lin; Qu, Jin; Zhang, Li; Fu, Yingyi; Teixeira, Ivo F; McPherson, Ian James; He, Heyong; Tsang, Shik Chi Edman

    2016-02-24

    Nano metal oxides are becoming widely used in industrial, commercial and personal products (semiconductors, optics, solar cells, catalysts, paints, cosmetics, sun-cream lotions, etc.). However, the relationship of surface features (exposed planes, defects and chemical functionalities) with physiochemical properties is not well studied primarily due to lack of a simple technique for their characterization. In this study, solid state (31)P MAS NMR is used to map surfaces on various ZnO samples with the assistance of trimethylphosphine (TMP) as a chemical probe. As similar to XRD giving structural information on a crystal, it is demonstrated that this new surface-fingerprint technique not only provides qualitative (chemical shift) but also quantitative (peak intensity) information on the concentration and distribution of cations and anions, oxygen vacancies and hydroxyl groups on various facets from a single deconvoluted (31)P NMR spectrum. On the basis of this technique, a new mechanism for photocatalytic •OH radical generation from direct surface-OH oxidation is revealed, which has important implications regarding the safety of using nano oxides in personal care products. PMID:26812527

  16. On the use of 31P NMR for the quantification of hydrosoluble phosphorus-containing compounds in coral host tissues and cultured zooxanthellae

    NASA Astrophysics Data System (ADS)

    Godinot, Claire; Gaysinski, Marc; Thomas, Olivier P.; Ferrier-Pagès, Christine; Grover, Renaud

    2016-02-01

    31P Nuclear Magnetic Resonance (NMR) was assessed to investigate the phosphorus-containing compounds present in the tissues of the scleractinian coral Stylophora pistillata as well as of cultured zooxanthellae (CZ). Results showed that phosphorus-containing compounds observed in CZ were mainly phosphate and phosphate esters. Phosphate accounted for 19 ± 2% of the total phosphorus compounds observed in CZ maintained under low P-levels (0.02 μM). Adding 5 mM of dissolved inorganic phosphorus (KH2PO4) to the CZ culture medium led to a 3.1-fold increase in intracellular phosphate, while adding 5 mM of dissolved organic phosphorus led to a reduction in the concentration of phosphorus compounds, including a 2.5-fold intracellular phosphate decrease. In sharp contrast to zooxanthellae, the host mainly contained phosphonates, and to a lesser extent, phosphate esters and phosphate. Two-months of host starvation decreased the phosphate content by 2.4 fold, while bleaching of fed corals did not modify this content. Based on 31P NMR analyses, this study highlights the importance of phosphonates in the composition of coral host tissues, and illustrates the impact of phosphorus availability on the phosphorus composition of host tissues and CZ, both through feeding of the host and inorganic phosphorus enrichment of the CZ.

  17. 31P NMR characterization and efficiency of new types of water-insoluble phosphate fertilizers to supply plant-available phosphorus in diverse soil types.

    PubMed

    Erro, Javier; Baigorri, Roberto; Yvin, Jean-Claude; Garcia-Mina, Jose M

    2011-03-01

    Hydroponic plant experiments demonstrated the efficiency of a type of humic acid-based water-insoluble phosphate fertilizers, named rhizosphere controlled fertilizers (RCF), to supply available phosphorus (P) to different plant species. This effect was well correlated to the root release of specific organic acids. In this context, the aims of this study are (i) to study the chemical nature of RCF using solid-state (31)P NMR and (ii) to evaluate the real efficiency of RCF matrix as a source of P for wheat plants cultivated in an alkaline and acid soil in comparison with traditional water-soluble (simple superphosphate, SSP) and water-insoluble (dicalcium phosphate, DCP) P fertilizers. The (31)P NMR study revealed the formation of multimetal (double and triple, MgZn and/or MgZnCa) phosphates associated with chelating groups of the humic acid through the formation of metal bridges. With regard to P fertilizer efficiency, the results obtained show that the RCF matrix produced higher plant yields than SSP in both types of soil, with DCP and the water-insoluble fraction from the RCF matrix (WI) exhibiting the best results in the alkaline soil. By contrast, in the acid soil, DCP showed very low efficiency, WI performed on a par with SSP, and RCF exhibited the highest efficiency, thus suggesting a protector effect of humic acid from soil fixation. PMID:21254775

  18. On the use of 31P NMR for the quantification of hydrosoluble phosphorus-containing compounds in coral host tissues and cultured zooxanthellae

    PubMed Central

    Godinot, Claire; Gaysinski, Marc; Thomas, Olivier P.; Ferrier-Pagès, Christine; Grover, Renaud

    2016-01-01

    31P Nuclear Magnetic Resonance (NMR) was assessed to investigate the phosphorus-containing compounds present in the tissues of the scleractinian coral Stylophora pistillata as well as of cultured zooxanthellae (CZ). Results showed that phosphorus-containing compounds observed in CZ were mainly phosphate and phosphate esters. Phosphate accounted for 19 ± 2% of the total phosphorus compounds observed in CZ maintained under low P-levels (0.02 μM). Adding 5 mM of dissolved inorganic phosphorus (KH2PO4) to the CZ culture medium led to a 3.1-fold increase in intracellular phosphate, while adding 5 mM of dissolved organic phosphorus led to a reduction in the concentration of phosphorus compounds, including a 2.5-fold intracellular phosphate decrease. In sharp contrast to zooxanthellae, the host mainly contained phosphonates, and to a lesser extent, phosphate esters and phosphate. Two-months of host starvation decreased the phosphate content by 2.4 fold, while bleaching of fed corals did not modify this content. Based on 31P NMR analyses, this study highlights the importance of phosphonates in the composition of coral host tissues, and illustrates the impact of phosphorus availability on the phosphorus composition of host tissues and CZ, both through feeding of the host and inorganic phosphorus enrichment of the CZ. PMID:26902733

  19. 31P NMR characterization and efficiency of new types of water-insoluble phosphate fertilizers to supply plant-available phosphorus in diverse soil types.

    PubMed

    Erro, Javier; Baigorri, Roberto; Yvin, Jean-Claude; Garcia-Mina, Jose M

    2011-03-01

    Hydroponic plant experiments demonstrated the efficiency of a type of humic acid-based water-insoluble phosphate fertilizers, named rhizosphere controlled fertilizers (RCF), to supply available phosphorus (P) to different plant species. This effect was well correlated to the root release of specific organic acids. In this context, the aims of this study are (i) to study the chemical nature of RCF using solid-state (31)P NMR and (ii) to evaluate the real efficiency of RCF matrix as a source of P for wheat plants cultivated in an alkaline and acid soil in comparison with traditional water-soluble (simple superphosphate, SSP) and water-insoluble (dicalcium phosphate, DCP) P fertilizers. The (31)P NMR study revealed the formation of multimetal (double and triple, MgZn and/or MgZnCa) phosphates associated with chelating groups of the humic acid through the formation of metal bridges. With regard to P fertilizer efficiency, the results obtained show that the RCF matrix produced higher plant yields than SSP in both types of soil, with DCP and the water-insoluble fraction from the RCF matrix (WI) exhibiting the best results in the alkaline soil. By contrast, in the acid soil, DCP showed very low efficiency, WI performed on a par with SSP, and RCF exhibited the highest efficiency, thus suggesting a protector effect of humic acid from soil fixation.

  20. On the use of 31P NMR for the quantification of hydrosoluble phosphorus-containing compounds in coral host tissues and cultured zooxanthellae.

    PubMed

    Godinot, Claire; Gaysinski, Marc; Thomas, Olivier P; Ferrier-Pagès, Christine; Grover, Renaud

    2016-01-01

    (31)P Nuclear Magnetic Resonance (NMR) was assessed to investigate the phosphorus-containing compounds present in the tissues of the scleractinian coral Stylophora pistillata as well as of cultured zooxanthellae (CZ). Results showed that phosphorus-containing compounds observed in CZ were mainly phosphate and phosphate esters. Phosphate accounted for 19 ± 2% of the total phosphorus compounds observed in CZ maintained under low P-levels (0.02 μM). Adding 5 mM of dissolved inorganic phosphorus (KH2PO4) to the CZ culture medium led to a 3.1-fold increase in intracellular phosphate, while adding 5 mM of dissolved organic phosphorus led to a reduction in the concentration of phosphorus compounds, including a 2.5-fold intracellular phosphate decrease. In sharp contrast to zooxanthellae, the host mainly contained phosphonates, and to a lesser extent, phosphate esters and phosphate. Two-months of host starvation decreased the phosphate content by 2.4 fold, while bleaching of fed corals did not modify this content. Based on (31)P NMR analyses, this study highlights the importance of phosphonates in the composition of coral host tissues, and illustrates the impact of phosphorus availability on the phosphorus composition of host tissues and CZ, both through feeding of the host and inorganic phosphorus enrichment of the CZ. PMID:26902733

  1. In vivo 31P NMR Study of the Metabolism of Murine Mammary 16/C Adenocarcinoma and Its Response to Chemotherapy, X-Radiation, and Hyperthermia

    NASA Astrophysics Data System (ADS)

    Evanochko, W. T.; Ng, T. C.; Lilly, M. B.; Lawson, A. J.; Corbett, T. H.; Durant, J. R.; Glickson, J. D.

    1983-01-01

    31P NMR spectroscopy with surface coils has been used to monitor, in vivo, the phosphate metabolism of subcutaneously implanted mammary 16/C adenocarcinoma in C3H/He mice. This model tumor was studied during untreated tumor growth and after treatment with adriamycin, hyperthermia, and x-radiation. The mammary 16/C tumor exhibited a Gompertzian growth pattern. Levels of high-energy phosphate metabolites--phosphocreatine and ATP--decreased with increases in tumor mass. There was a concomitant increase in the level of Pi and a decrease in the apparent pH of the tumor. These spectral changes appear to reflect changes in tumor vascularization that accompany tumor growth, the tumor becoming progressively more hypoxic. Partial response of this tumor to chemotherapy with adriamycin was reflected in a small but measurable increase in the phosphocreatine resonance, a decrease in Pi, and a return of the intratumor pH to neutral. Hyperthermia resulted in progressive conversion of the 31P NMR spectrum to that of a dead tumor (high levels of Pi, small levels of residual sugar phosphates and pyridine dinucleotides, and acidic pH). X-irradiation (14.0 Gy) led to disappearance of the phosphocreatine peak within 15 min of treatment. Subsequently, this resonance grew back beyond its pretreatment level. As the tumor receded, its spectrum reflected the characteristics of aerobically metabolizing tissue (high levels of phosphocreatine and ATP and low levels of Pi and sugar phosphates).

  2. Studies of uptake and suppresion of Mn/sup 2 +/ migration in highly vacuolated sycamore (Acer pseudoplatanus L) cells by /sup 31/P NMR

    SciTech Connect

    Roby, C.; Bligny, R.; Douce, R.; Pfeffer, P.E.

    1987-04-01

    Recent /sup 31/P NMR studies have demonstrated that Mn/sup 2 +/ appears to invade the cells of heterogeneous excised tissue of corn root tips sequentially, first entering the cytoplasmic compartment, where it complexes with nucleotides and P/sub i/. Under aerobic conditions, further migration across the tonoplast, followed by vacoule trapping was visualized through paramagnetic broadening of the vacoular P/sub i/ resonance. Cultured cells such as Acer pseudoplatanus L offer better opportunities for studying cellular activity by /sup 31/P NMR because of their homogeneity and uniformly rapid response to various metabolic disturbances. In contrast to excised root tissue, Mn/sup 2 +/ showed no measurable accumulation in the cytoplasmic compartments of these cells under aerobic conditions. However, a rapid crossing of the large tonoplast resulted in immediate vacuolar metal ion sequestration. Anoxia did not foster leakage of Mn/sup 2 +/ from the vacuole to the cytoplasm, while hypoxia completely halted all movement of Mn/sup 2 +/ across the plasmalema. This disparity in terms of cell and tissue morphology, membrane permeability and possible tissue trapping of metal ions will be discussed.

  3. Carbon-13, sup 15 N, and sup 31 P NMR studies on 6-hydroxy-L-nicotine oxidase from Arthrobacter oxidans

    SciTech Connect

    Pust, S.; Vervoort, J.; Decker, K.; Bacher, A.; Mueller, F. )

    1989-01-24

    The interaction between the apoprotein of 6-hydroxy-L-nicotine oxidase from Arthrobacter oxidans and the prosthetic group FAD has been investigated by {sup 13}C, {sup 15}N and {sup 31}P NMR techniques. The FAD prosthetic group was selectively enriched in {sup 13}C and {sup 15}N isotopes by adding isotopically labeled riboflavin derivatives to the growth medium of riboflavin-requiring mutant cells. In the oxidized state the chemical shift of the C(7) and C(8) atoms indicates that the xylene moiety of the isoalloxazine ring is embedded in a hydrophobic environment. The binding of the competitive inhibitor, 6-hydroxy-D-nicotine, influences the resonances of the C(4a) and the N(5) atom strongly. It is suggested that these shifts are due to a strong hydrogen-bonding interaction between the N(5) atom and the inhibitor. On reduction all resonances, except those of the C(10a) and the N(1) atoms, shift upfield, indicating the increased electron density in the ring system. It can unambiguously be concluded from the chemical shift of the N(1) atom that the reduced flavin is anionic. The doublet character of the N(3) and N(5) resonances suggests that bulk water has no access to the active center. The strong downfield shift of the N(1) position indicates that this atom is embedded in a polar environment, but it does not indicate the presence of a positively charged residue. The {sup 31}P NMR spectra show that the resonances of the pyrophosphate group of the bound FAD differ slightly from those of free FAD. Besides the {sup 31}P resonances from FAD, four peaks around 0 ppm are observed that belongs to bound phosphorus residues. The residues are not located close to the isoalloxazine ring.

  4. Spin-echo methods for the determination of 31P transverse relaxation times of the ATP NMR signals in vivo.

    PubMed

    Straubinger, K; Jung, W I; Bunse, M; Lutz, O; Küper, K; Dietze, G

    1994-01-01

    31P magnetic resonance spectroscopy (MRS) examinations of the calf muscles of healthy volunteers were performed to determine T2 of the coupled ATP signals by use of the Hahn spin-echo and the frequency-selective spin-echo method. Additional measurements with the J-coupling refocused double echo are presented. The most reliable determination of T2 relaxation times is possible with the frequency-selective spin echo. The other methods yield substantially wrong results. Theoretical explanations are given how J-coupling and pulse-angle deviations affect the signals and therefore the T2 determinations. The calculations for a weakly coupled homonuclear AX spin system are shown because they demonstrate most of the relevant facts. In addition, some important results for a homonuclear AMX spin system, which the ATP is considered to be, are given.

  5. A gradient scheme suitable for localized shimming and in vivo 1H/31P STEAM and ISIS NMR spectroscopy.

    PubMed

    Yongbi, N M; Payne, G S; Leach, M O

    1994-12-01

    A gradient scheme is presented which may be used for STEAM or ISIS localization. One application of the scheme is to perform single-shot STEAM shimming prior to data acquisition with STEAM and ISIS, using identical gradient amplitudes and durations. Using conventional STEAM to shim for ISIS can produce line-shape distortions induced by different eddy currents in the two sequences; with this gradient scheme the problem is minimized. Line-shape improvements of STEAM and ISIS localized data obtained after volume localized shimming with the proposed STEAM sequence are demonstrated. The localization performance of the STEAM and ISIS sequences are demonstrated on phantoms and in vivo for 1H and 31P metabolites. PMID:7869899

  6. Combining solid-state and solution-state 31P NMR to study in vivo phosphorus metabolism.

    PubMed Central

    Cholli, A L; Yamane, T; Jelinski, L W

    1985-01-01

    Otherwise unavailable information concerning the distribution of phosphorylated compounds in biological systems is obtained by a combined solid-state/solution-state NMR approach, illustrated here for oocytes from Rana pipiens. General methodology is developed, and further extensions are proposed. The following conclusions pertain to the specific system under examination. (i) Nucleoside phosphates can be observed by magic-angle sample spinning of the lyophilized material. (ii) The solid-state NMR technique of dipolar decoupling provides no additional resolution of the phospholipid and phosphoprotein components of the yolk. However, cellular death produces sufficient pH changes to cause the phospholipid and protein phosphate peaks to become resolvable. The concentration of nucleoside phosphates also decreases. (iii) The phospholipid and phosphoprotein components are shown by computer simulation to be present in a ratio of 40:60, respectively. (iv) The amounts of inorganic phosphate, nucleoside phosphates, and sugar phosphates are determined by solution-state NMR observation of the perchloric acid extract of the oocytes. PMID:3871524

  7. In vivo /sup 31/P NMR studies of corn root tissue and its uptake of toxic metals. [Zea mays L

    SciTech Connect

    Pfeffer, P.E.; Tu, S.I.; Gerasimowicz, W.V.; Cavanaugh, J.R.

    1986-01-01

    Excised corn root tissue has been evaluated for its viability, integrity of compartmentation, intracellular pH gradients, total mobile phosphorus content and nucleotide concentrations under different levels of acidity, and mineral stresses using in vivo /sup 31/P nuclear magnetic resonance spectroscopy at 21 to 23/sup 0/C. Perfusion with Al/sup 3 +/ ion at low pH (4.0) for 20 hours caused the overall concentration of nucleotides in the cytoplasm to decrease significantly relative to the control. Respiratory activity as measured by O/sub 2/ uptake decreased by a comparable amount over this time period. The addition of glucose to the Al-containing perfusate negated the inhibitory effects on the respiratory system. Treatment of the tissue with paramagnetic manganese ion while perfusing in the presence of O/sub 2/ allowed for the observation of the sequence of events leading to the irreversible trapping of Mn/sup 2 +/ in the vacuole. Pretreatment of the roots with Mg/sup 2 +/ prevented Mn/sup 2 +/ migration to the vacuole over the time period of this experiment. Hypoxia prevented all but a limited uptake of Mn/sup 2 +/ into the cytoplasm of the root tips. No evidence of Mn/sup 2 +/ complexation of either cytoplasmic or vacuole Pi suggests that the energy derived from O/sub 2/ consuming processes is necessary for the facilitated movement of this divalent cation.

  8. Characterizing phosphorus speciation of Chesapeake Bay sediments using chemical extraction, 31P NMR, and X-ray absorption fine structure spectroscopy.

    PubMed

    Li, Wei; Joshi, Sunendra R; Hou, Guangjin; Burdige, David J; Sparks, Donald L; Jaisi, Deb P

    2015-01-01

    Nutrient contamination has been one of the lingering issues in the Chesapeake Bay because the bay restoration is complicated by temporally and seasonally variable nutrient sources and complex interaction between imported and regenerated nutrients. Differential reactivity of sedimentary phosphorus (P) pools in response to imposed biogeochemical conditions can record past sediment history and therefore a detailed sediment P speciation may provide information on P cycling particularly the stability of a P pool and the formation of one pool at the expense of another. This study examined sediment P speciation from three sites in the Chesapeake Bay: (i) a North site in the upstream bay, (ii) a middle site in the central bay dominated by seasonally hypoxic bottom water, and (iii) a South site at the bay-ocean boundary using a combination of sequential P extraction (SEDEX) and spectroscopic techniques, including (31)P NMR, P X-ray absorption near edge structure spectroscopy (XANES), and Fe extended X-ray absorption fine structure (EXAFS). Results from sequential P extraction reveal that sediment P is composed predominantly of ferric Fe-bound P and authigenic P, which was further confirmed by solid-state (31)P NMR, XANES, and EXAFS analyses. Additionally, solution (31)P NMR results show that the sediments from the middle site contain high amounts of organic P such as monoesters and diesters, compared to the other two sites, but that these compounds rapidly decrease with sediment depth indicating remineralized P could have precipitated as authigenic P. Fe EXAFS enabled to identify the changes in Fe mineral composition and P sinks in response to imposed redox condition in the middle site sediments. The presence of lepidocrocite, vermiculite, and Fe smectite in the middle site sediments indicates that some ferric Fe minerals can still be present along with pyrite and vivianite, and that ferric Fe-bound P pool can be a major P sink in anoxic sediments. These results provide

  9. Characterizing phosphorus speciation of Chesapeake Bay sediments using chemical extraction, 31P NMR, and X-ray absorption fine structure spectroscopy.

    PubMed

    Li, Wei; Joshi, Sunendra R; Hou, Guangjin; Burdige, David J; Sparks, Donald L; Jaisi, Deb P

    2015-01-01

    Nutrient contamination has been one of the lingering issues in the Chesapeake Bay because the bay restoration is complicated by temporally and seasonally variable nutrient sources and complex interaction between imported and regenerated nutrients. Differential reactivity of sedimentary phosphorus (P) pools in response to imposed biogeochemical conditions can record past sediment history and therefore a detailed sediment P speciation may provide information on P cycling particularly the stability of a P pool and the formation of one pool at the expense of another. This study examined sediment P speciation from three sites in the Chesapeake Bay: (i) a North site in the upstream bay, (ii) a middle site in the central bay dominated by seasonally hypoxic bottom water, and (iii) a South site at the bay-ocean boundary using a combination of sequential P extraction (SEDEX) and spectroscopic techniques, including (31)P NMR, P X-ray absorption near edge structure spectroscopy (XANES), and Fe extended X-ray absorption fine structure (EXAFS). Results from sequential P extraction reveal that sediment P is composed predominantly of ferric Fe-bound P and authigenic P, which was further confirmed by solid-state (31)P NMR, XANES, and EXAFS analyses. Additionally, solution (31)P NMR results show that the sediments from the middle site contain high amounts of organic P such as monoesters and diesters, compared to the other two sites, but that these compounds rapidly decrease with sediment depth indicating remineralized P could have precipitated as authigenic P. Fe EXAFS enabled to identify the changes in Fe mineral composition and P sinks in response to imposed redox condition in the middle site sediments. The presence of lepidocrocite, vermiculite, and Fe smectite in the middle site sediments indicates that some ferric Fe minerals can still be present along with pyrite and vivianite, and that ferric Fe-bound P pool can be a major P sink in anoxic sediments. These results provide

  10. Structure and Membrane Interactions of the Antibiotic Peptide Dermadistinctin K by Multidimensional Solution and Oriented 15N and 31P Solid-State NMR Spectroscopy

    PubMed Central

    Verly, Rodrigo M.; Moraes, Cléria Mendonça de; Resende, Jarbas M.; Aisenbrey, Christopher; Bemquerer, Marcelo Porto; Piló-Veloso, Dorila; Valente, Ana Paula; Almeida, Fábio C.L.; Bechinger, Burkhard

    2009-01-01

    DD K, a peptide first isolated from the skin secretion of the Phyllomedusa distincta frog, has been prepared by solid-phase chemical peptide synthesis and its conformation was studied in trifluoroethanol/water as well as in the presence of sodium dodecyl sulfate and dodecylphosphocholine micelles or small unilamellar vesicles. Multidimensional solution NMR spectroscopy indicates an α-helical conformation in membrane environments starting at residue 7 and extending to the C-terminal carboxyamide. Furthermore, DD K has been labeled with 15N at a single alanine position that is located within the helical core region of the sequence. When reconstituted into oriented phosphatidylcholine membranes the resulting 15N solid-state NMR spectrum shows a well-defined helix alignment parallel to the membrane surface in excellent agreement with the amphipathic character of DD K. Proton-decoupled 31P solid-state NMR spectroscopy indicates that the peptide creates a high level of disorder at the level of the phospholipid headgroup suggesting that DD K partitions into the bilayer where it severely disrupts membrane packing. PMID:19289046

  11. Rate equation for creatine kinase predicts the in vivo reaction velocity: /sup 31/P NMR surface coil studies in brain, heart, and skeletal muscle of the living rat

    SciTech Connect

    Bittl, J.A.; DeLayre, J.; Ingwall, J.S.

    1987-09-22

    Brain, heart, and skeletal muscle contain four different creatine kinase isozymes and various concentrations of substrates for the creatine kinase reaction. To identify if the velocity of the creatine kinase reaction under cellular conditions is regulated by enzyme activity and substrate concentrations as predicted by the rate equation, the authors used /sup 31/P NMR and spectrophotometric techniques to measure reaction velocity, enzyme content, isozyme distribution, and concentrations of substrates in brain, heart, and skeletal muscle of living rat under basal or resting conditions. The total tissue activity of creatine kinase in the direction of MgATP synthesis provided an estimate for V/sub max/ and exceeded the NMR-determined in vivo reaction velocities by an order of magnitude. The isozyme composition varied among the three tissues: >99% BB for brain; 14% MB, 61% MM, and 25% mitochondrial for heart; and 98% MM and 2% mitochondrial for skeletal muscle. The NMR-determined reaction velocities agreed with predicted values from the creatine kinase rate equation. The concentrations of free creatine and cytosolic MgADP, being less than or equal to the dissociation constants for each isozyme, were dominant terms in the creatine kinase rate equation for predicting the in vivo reaction velocity. Thus, they observed that the velocity of the creatine kinase reaction is regulated by total tissue enzyme activity and by the concentrations of creatine and MgADP in a manner that is independent of isozyme distribution.

  12. The investigation of membrane binding by amphibian peptide agonists of CCK2R using (31)P and (2)H solid-state NMR.

    PubMed

    Sherman, Patrick J; Separovic, Frances; Bowie, John H

    2014-05-01

    It has been proposed that some neuropeptides may be anchored to the cell membranes prior to attaching to the adjacent active sites of transmembrane receptors. The three amphibian skin neuropeptides signiferin 1 [RLCIPYIIPC(OH)] (smooth muscle active and immunomodulator), riparin 1.1 [[RLCIPVIFPC(OH)] (immunomodulator) and rothein 1 [SVSNIPESIGF(OH)] (immunomodulator) act via CCK2 transmembrane receptors. A combination of (31)P and (2)H solid state NMR studies of each of these three peptides in eukaryotic phospholipid models at 25°C shows that rothein 1 does not interact with the membrane at all. In contrast, both of the cyclic disulfides signiferin 1 and riparin 1.1 interact with phospholipid head groups and partially penetrate into the upper leaflet of the model bilayer, but to different extents. These interactions are not sufficiently effective to cause disruption of the lipid bilayer since the peptides are not antimicrobial, anticancer, antifungal nor active against enveloped viruses. PMID:24582625

  13. Determination of glucan phosphorylation using heteronuclear 1H, 13C double and 1H, 13C, 31P triple-resonance NMR spectra.

    PubMed

    Schmieder, Peter; Nitschke, Felix; Steup, Martin; Mallow, Keven; Specker, Edgar

    2013-10-01

    Phosphorylation and dephosphorylation of starch and glycogen are important for their physicochemical properties and also their physiological functions. It is therefore desirable to reliably determine the phosphorylation sites. Heteronuclear multidimensional NMR-spectroscopy is in principle a straightforward analytical approach even for complex carbohydrate molecules. With heterogeneous samples from natural sources, however, the task becomes more difficult because a full assignment of the resonances of the carbohydrates is impossible to obtain. Here, we show that the combination of heteronuclear (1) H,(13) C and (1) H,(13) C,(31) P techniques and information derived from spectra of a set of reference compounds can lead to an unambiguous determination of the phosphorylation sites even in heterogeneous samples. PMID:23913630

  14. Determination of glucan phosphorylation using heteronuclear 1H, 13C double and 1H, 13C, 31P triple-resonance NMR spectra.

    PubMed

    Schmieder, Peter; Nitschke, Felix; Steup, Martin; Mallow, Keven; Specker, Edgar

    2013-10-01

    Phosphorylation and dephosphorylation of starch and glycogen are important for their physicochemical properties and also their physiological functions. It is therefore desirable to reliably determine the phosphorylation sites. Heteronuclear multidimensional NMR-spectroscopy is in principle a straightforward analytical approach even for complex carbohydrate molecules. With heterogeneous samples from natural sources, however, the task becomes more difficult because a full assignment of the resonances of the carbohydrates is impossible to obtain. Here, we show that the combination of heteronuclear (1) H,(13) C and (1) H,(13) C,(31) P techniques and information derived from spectra of a set of reference compounds can lead to an unambiguous determination of the phosphorylation sites even in heterogeneous samples.

  15. A 31P NMR spectroscopy study of Xenopus laevis heart perfused in vitro with creatinol-O-phosphate, phosphocreatine, adenosine triphosphate, fructose diphosphate and ouabain.

    PubMed

    Olsen, J I; Rossini, P; Schweizer, M P; Bernardi, M; Moretti, V; Re, L; Rossini, L

    1993-09-01

    Xenopus laevis heart was studied by 31P NMR using a 200 MHz proton spectrometer; hearts were perfused, at pH 7.35 and room temperature, with normal oxygenated or K(+)-enriched Ringer. Solution was later added with creatinol-O-phosphate (COP), phosphocreatine (PCr), adenosine triphosphate (ATP), fructose-1,6-diphosphate (FDP) and ouabain. NMR spectra of the heart show organic phosphomono- and phosphodi-esters, inorganic phosphate, PCr, overlapping alpha-ATP/ADP and gamma-ATP/beta-ADP, and beta-ATP signals. Their chemical shift positions and areas showed no significant changes in the course of 1.5 h perfusions with either solution, except in a few preparations, whether the heart was beating or reversibly arrested. While COP reduced the signals in beating hearts, the same spectra exhibited no consistent, substantial changes under PCr, ATP and FDP 1 to 10 mM, pH 7.35 perfusion with either solution, nor when ouabain mumol was added. The spectra are briefly discussed in comparison with those observed in the perfused heart of mammals (mostly rat), and particularly with those obtained in the frog (Rana temporaria) heart, both by analysing the bioenergetic equilibria on the basis of total tissue substrate levels measured in extracts of freeze-clamped tissue, and by evaluating cytochrome-b, flavin and pyridine nucleotide in vitro oxido-reduction read-outs in separate, similar experimental settings.

  16. Correcting human heart 31P NMR spectra for partial saturation. Evidence that saturation factors for PCr/ATP are homogeneous in normal and disease states

    NASA Astrophysics Data System (ADS)

    Bottomley, Paul A.; Hardy, Christopher J.; Weiss, Robert G.

    Heart PCr/ATP ratios measured from spatially localized 31P NMR spectra can be corrected for partial saturation effects using saturation factors derived from unlocalized chest surface-coil spectra acquired at the heart rate and approximate Ernst angle for phosphor creatine (PCr) and again under fully relaxed conditions during each 31P exam. To validate this approach in studies of normal and disease states where the possibility of heterogeneity in metabolite T1 values between both chest muscle and heart and normal and disease states exists, the properties of saturation factors for metabolite ratios were investigated theoretically under conditions applicable in typical cardiac spectroscopy exams and empirically using data from 82 cardiac 31P exams in six study groups comprising normal controls ( n = 19) and patients with dilated ( n = 20) and hypertrophic ( n = 5) cardiomyopathy, coronary artery disease ( n = 16), heart transplants ( n = 19), and valvular heart disease ( n = 3). When TR ≪ T1,(PCr), with T1(PCr) ⩾ T1(ATP), the saturation factor for PCr/ATP lies in the range 1.5 ± 0.5, regardless of the T1 values. The precise value depends on the ratio of metabolite T1 values rather than their absolute values and is insensitive to modest changes in TR. Published data suggest that the metabolite T1 ratio is the same in heart and muscle. Our empirical data reveal that the saturation factors do not vary significantly with disease state, nor with the relative fractions of muscle and heart contributing to the chest surface-coil spectra. Also, the corrected myocardial PCr/ATP ratios in each normal or disease state bear no correlation with the corresponding saturation factors nor the fraction of muscle in the unlocalized chest spectra. However, application of the saturation correction (mean value, 1.36 ± 0.03 SE) significantly reduced scatter in myocardial PCr/ATP data by 14 ± 11% (SD) ( p ⩽ 0.05). The findings suggest that the relative T1 values of PCr and ATP are

  17. Functional pools of fast and slow twitch fibers observed by /sup 31/P-NMR during exercise of flexor wrist muscles in man

    SciTech Connect

    Park, J.H.; Park, C.R.; Brown, R.L.; Chance, B.

    1987-05-01

    Functional compartments of fast and slow twitch fibers have been observed by /sup 31/P-NMR spectroscopy during exercise of the wrist flexor muscles in a sedentary, young male subject. Values of Pi, phosphocreatine (PCr) and adenine nucleotides were determined at rest and during an exercise protocol. The subject flexed his wrist muscles at 20% of maximum strength every 5 sec for 6 min and then increased his effort in the next two 6 min intervals to 40% and 60% of maximum. With exercise, the Pi/PCr rose rapidly to the exceptionally high value of 2.2 at 60% effort. As the Pi increased, the initial single peak (pH 7.0-6.9) split into two distinct components with pH values of 6.8 and 6.3. Quantitatively, distribution of the Pi was 40% in the pH 6.8 peak and 60% in the pH 6.3 peak as determined by area estimation following curve fitting. This presumably reflects two pools of Pi corresponding to the oxidative (slow twitch, high pH) and glycolytic (fast twitch, low pH) fibers. In the second identical exercise sequence which followed immediately, only one Pi peak (pH 6.8-6.9) appeared. This suggested that the glycolytic contribution to energy production was largely exhausted and the residual energy was derived from oxidative metabolism. During exercise at high levels, total phosphate decreased due primarily to loss of NMR visible adenine nucleotides. Similar phenomena have been observed in three other sedentary individuals, but not in trained athletes.

  18. 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.

  19. Facilitated transport of Mn2+ in sycamore (Acer pseudoplatanus) cells and excised maize root tips. A comparative 31P n.m.r. study in vivo.

    PubMed

    Roby, C; Bligny, R; Douce, R; Tu, S I; Pfeffer, P E

    1988-06-01

    Movement of paramagnetic Mn2+ into sycamore (Acer pseudoplatanus) cells has been indirectly examined by observing the line broadening exhibited in its 31P n.m.r. spectra. Mn2+ was observed to pass into the vacuole, while exhibiting a very minor accumulation in the cytoplasm. With time, gradual leakage of phosphate from the vacuole to the cytoplasm was observed along with an increase in glucose-6-phosphate. Anoxia did not appear to affect the relative distribution of Mn2+ in the cytoplasm and vacuole. Under hypoxic conditions restriction of almost all movement of Mn2+ across the plasmalemma as well as the tonoplast was observed. In contrast, maize root tips showed entry and complete complexation of nucleotide triphosphate by Mn2+ during hypoxia. The rate of passage of Mn2+ across the tonoplast in both sycamore and maize root cells is approximately the same. However, the rates of facilitated movement across the respective plasma membranes appear to differ. More rapid movement of Mn2+ across the plasmalemma in maize root tip cells allows a gradual build-up of metal ion in the cytoplasm prior to its diffusion across the tonoplast. Sycamore cells undergo a slower uptake of Mn2+ into their cytoplasms (comparable with the rate of diffusion through the tonoplast), so little or no observable accumulation of Mn2+ is observed in this compartment.

  20. Conformational transitions of the phosphodiester backbone in native DNA: two-dimensional magic-angle-spinning 31P-NMR of DNA fibers.

    PubMed Central

    Song, Z; Antzutkin, O N; Lee, Y K; Shekar, S C; Rupprecht, A; Levitt, M H

    1997-01-01

    Solid-state 31P-NMR is used to investigate the orientation of the phosphodiester backbone in NaDNA-, LiDNA-, MgDNA-, and NaDNA-netropsin fibers. The results for A- and B-DNA agree with previous interpretations. We verify that the binding of netropsin to NaDNA stabilizes the B form, and find that in NaDNA, most of the phosphate groups adopt a conformation typical of the A form, although there are minor components with phosphate orientations close to the B form. For LiDNA and MgDNA samples, on the other hand, we find phosphate conformations that are in variance with previous models. These samples display x-ray diffraction patterns that correspond to C-DNA. However, we find two distinct phosphate orientations in these samples, one resembling that in B-DNA, and one displaying a twist of the PO4 groups about the O3-P-O4 bisectors. The latter conformation is not in accordance with previous models of C-DNA structure. Images FIGURE 2 FIGURE 3 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 FIGURE 10 FIGURE 14 PMID:9284321

  1. Solid state {sup 31}P MAS NMR spectroscopy and conductivity measurements on NbOPO{sub 4} and H{sub 3}PO{sub 4} composite materials

    SciTech Connect

    Risskov Sørensen, Daniel; Nielsen, Ulla Gro; Skou, Eivind M.

    2014-11-15

    A systematic study of composite powders of niobium oxide phosphate (NbOPO{sub 4}) and phosphoric acid (H{sub 3}PO{sub 4}) has been performed in order to characterize the material's ability to perform as an electrolyte material in medium temperature fuel cells and electrolyzers. Powders of H{sub 3}PO{sub 4} contents between 13.1 and 74.2 M% were produced and characterized with powder X-ray diffraction, {sup 31}P MAS NMR and impedance spectroscopy. NMR revealed that a significant degree of dehydration and vaporization of H{sub 3}PO{sub 4} takes place above 200 °C, and increases with temperature. At 500 °C the NbOPO{sub 4} and H{sub 3}PO{sub 4} has reacted to form niobium pyrophosphate (Nb{sub 2}P{sub 4}O{sub 15}). Impedance spectroscopy showed an increase in conductivity with increasing acid concentration, whereas the conductivity decreased slightly with increasing temperature. The highest conductivity measured was 2.5·10{sup −3} S/cm for a sample containing 74.2 M% of H{sub 3}PO{sub 4}. Lastly, it was shown that NbOPO{sub 4} has no significant conductivity of its own. - Graphical abstract: Conductivity of NbOPO{sub 4}/H{sub 3}PO{sub 4} composites as a function of equivalent P{sub 2}O{sub 5} content. The conductivity is insignificant for pure NbOPO{sub 4}. - Highlights: • Composites have been made from NbOPO{sub 4} and H{sub 3}PO{sub 4}. • The composites composition has been investigated with solid state NMR. • The composites have shown clear signs of acid dehydration upon heating. • The conductivity of the composites increases for increasing acid content. • NbOPO{sub 4} has no significant conductivity of its own.

  2. Catalytic mechanism of α-phosphate attack in dUTPase is revealed by X-ray crystallographic snapshots of distinct intermediates, 31P-NMR spectroscopy and reaction path modelling.

    PubMed

    Barabás, Orsolya; Németh, Veronika; Bodor, Andrea; Perczel, András; Rosta, Edina; Kele, Zoltán; Zagyva, Imre; Szabadka, Zoltán; Grolmusz, Vince I; Wilmanns, Matthias; Vértessy, Beáta G

    2013-12-01

    Enzymatic synthesis and hydrolysis of nucleoside phosphate compounds play a key role in various biological pathways, like signal transduction, DNA synthesis and metabolism. Although these processes have been studied extensively, numerous key issues regarding the chemical pathway and atomic movements remain open for many enzymatic reactions. Here, using the Mason-Pfizer monkey retrovirus dUTPase, we study the dUTPase-catalyzed hydrolysis of dUTP, an incorrect DNA building block, to elaborate the mechanistic details at high resolution. Combining mass spectrometry analysis of the dUTPase-catalyzed reaction carried out in and quantum mechanics/molecular mechanics (QM/MM) simulation, we show that the nucleophilic attack occurs at the α-phosphate site. Phosphorus-31 NMR spectroscopy ((31)P-NMR) analysis confirms the site of attack and shows the capability of dUTPase to cleave the dUTP analogue α,β-imido-dUTP, containing the imido linkage usually regarded to be non-hydrolyzable. We present numerous X-ray crystal structures of distinct dUTPase and nucleoside phosphate complexes, which report on the progress of the chemical reaction along the reaction coordinate. The presently used combination of diverse structural methods reveals details of the nucleophilic attack and identifies a novel enzyme-product complex structure. PMID:23982515

  3. Catalytic mechanism of α-phosphate attack in dUTPase is revealed by X-ray crystallographic snapshots of distinct intermediates, 31P-NMR spectroscopy and reaction path modelling

    PubMed Central

    Barabás, Orsolya; Németh, Veronika; Bodor, Andrea; Perczel, András; Rosta, Edina; Kele, Zoltán; Zagyva, Imre; Szabadka, Zoltán; Grolmusz, Vince I.; Wilmanns, Matthias; Vértessy, Beáta G.

    2013-01-01

    Enzymatic synthesis and hydrolysis of nucleoside phosphate compounds play a key role in various biological pathways, like signal transduction, DNA synthesis and metabolism. Although these processes have been studied extensively, numerous key issues regarding the chemical pathway and atomic movements remain open for many enzymatic reactions. Here, using the Mason–Pfizer monkey retrovirus dUTPase, we study the dUTPase-catalyzed hydrolysis of dUTP, an incorrect DNA building block, to elaborate the mechanistic details at high resolution. Combining mass spectrometry analysis of the dUTPase-catalyzed reaction carried out in and quantum mechanics/molecular mechanics (QM/MM) simulation, we show that the nucleophilic attack occurs at the α-phosphate site. Phosphorus-31 NMR spectroscopy (31P-NMR) analysis confirms the site of attack and shows the capability of dUTPase to cleave the dUTP analogue α,β-imido-dUTP, containing the imido linkage usually regarded to be non-hydrolyzable. We present numerous X-ray crystal structures of distinct dUTPase and nucleoside phosphate complexes, which report on the progress of the chemical reaction along the reaction coordinate. The presently used combination of diverse structural methods reveals details of the nucleophilic attack and identifies a novel enzyme–product complex structure. PMID:23982515

  4. Structural investigations of silicate-phosphate glasses containing MoO3 by FTIR, Raman and 31P MAS NMR spectroscopies.

    PubMed

    Szumera, M

    2014-09-15

    Molybdenum is a transition metal (refers to the "d" block of the periodic table) whose atom has an incomplete d sub-shell. It is known that in silicate glasses molybdenum may exist under four oxidation states: Mo6+, Mo5+, Mo4+ and Mo3+, simultaneously molybdenum cations, depending on their content in the glass network, may either be a glass forming component, or act as a modifier. The contemporary literature data show studies conducted mostly on the structure of silicate, phosphate, borate and borosilicate glasses containing molybdenum ions, but not silicate-phosphate glasses. Therefore, the author has undertaken detailed studies using FTIR, Raman and 31P MAS NMR techniques in order to examine the effect of MoO3 addition into the structure of silicate-phosphate glasses from SiO2P2O5K2OCaOMgO system. On the basis of obtained results it was concluded that molybdenum ions in the analysed glasses act as a modifier, which follows from the gradual breakage of oxygen bridges, i.e. POP, SiOSi, and SiOP, and the following formation of connections such as Mo[MoO4]OSi and/or Mo[MoO4]OP. In summary, it is concluded that the increase of MoO3 content (up to 4.4 mol.%) in the structure of glasses of SiO2P2O5K2OMgOCaO system results in weakening of the structure and gradual increase of the degree of silico-oxygen and phosphor-oxygen frameworks depolymerisation.

  5. Structural investigations of silicate-phosphate glasses containing MoO3 by FTIR, Raman and 31P MAS NMR spectroscopies.

    PubMed

    Szumera, M

    2014-09-15

    Molybdenum is a transition metal (refers to the "d" block of the periodic table) whose atom has an incomplete d sub-shell. It is known that in silicate glasses molybdenum may exist under four oxidation states: Mo6+, Mo5+, Mo4+ and Mo3+, simultaneously molybdenum cations, depending on their content in the glass network, may either be a glass forming component, or act as a modifier. The contemporary literature data show studies conducted mostly on the structure of silicate, phosphate, borate and borosilicate glasses containing molybdenum ions, but not silicate-phosphate glasses. Therefore, the author has undertaken detailed studies using FTIR, Raman and 31P MAS NMR techniques in order to examine the effect of MoO3 addition into the structure of silicate-phosphate glasses from SiO2P2O5K2OCaOMgO system. On the basis of obtained results it was concluded that molybdenum ions in the analysed glasses act as a modifier, which follows from the gradual breakage of oxygen bridges, i.e. POP, SiOSi, and SiOP, and the following formation of connections such as Mo[MoO4]OSi and/or Mo[MoO4]OP. In summary, it is concluded that the increase of MoO3 content (up to 4.4 mol.%) in the structure of glasses of SiO2P2O5K2OMgOCaO system results in weakening of the structure and gradual increase of the degree of silico-oxygen and phosphor-oxygen frameworks depolymerisation. PMID:24759778

  6. The regulation of intracellular pH studied by 31P- and 1H-NMR spectroscopy in superfused guinea-pig cerebral cortex slices.

    PubMed

    Brooks, K J; Bachelard, H S

    1992-10-01

    (1) The intracellular pH (pHi) of superfused slices of guinea-pig cerebral cortex was measured in 31P-NMR spectra using the chemical shifts of intracellular inorganic phosphate (Pi) and of 2-deoxyglucose 6-phosphate (DOG6P). The pHi was found to be 7.30 +/- 0.04 (SD, n = 15) in bicarbonate-buffered medium and 7.20 +/- 0.05 (n = 10, P < 0.001) in bicarbonate-free HEPES buffer of the same pH (7.4). (2) Decreases in pHe below 7.05 resulted in pHi falling to similar values, with a decrease in the energy state. There was no change in intracellular lactate as assessed by 1H-NMR. (3) The tissues showed an ability to buffer higher pH: increasing pHe to 8.0 had no effect on pHi, PCr or lactate. (4) In order to characterize possible mechanisms of pH regulation in the tissue, the recovery from acid insult was investigated under various conditions. Initially pHi was decreased to 6.44 +/- 0.15 (n = 15) by exposure to media containing 6 mM bicarbonate gassed with O2/CO2, 80:20 (pHe 6.4). When this medium was replaced by normal bicarbonate buffer (pH 7.4) there was full recovery of pHi to 7.31 +/- 0.05 (n = 15), whereas replacing the buffer with HEPES resulted in incomplete recovery of pHi to 6.88 +/- 0.15 (n = 15, P < 0.001). (5) In the presence of the carbonic anhydrase inhibitor, acetazolamide (1 mM), or the sodium/proton exchange inhibitor, amiloride (1 mM), there was an incomplete return of pHi to the control value (pHi 6.90 +/- 0.20, n = 5, P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1303163

  7. Hormonally induced modulation in the phosphate metabolites of breast cancer: analysis of in vivo 31P MRS signals with a modified prony method.

    PubMed

    Viti, V; Ragona, R; Guidoni, L; Barone, P; Furman, E; Degani, H

    1997-08-01

    A modified Prony method (MPM) was applied to analyze the main signals present in spatially resolved 31P NMR spectra of MCF7 breast tumors implanted in nude mice. First, the method was tested on synthetic data to establish its limits of reliability. Its performance with respect to peak identification and quantification of signal intensities was then exploited on data from three implanted tumors during hormonal manipulation with estrogen and the antiestrogenic drug tamoxifen. The phosphomonoester peak was resolved into phosphocholine (PC) and phosphoethanolamine (PE). Treatment with tamoxifen led to a significant reduction in the PE to PE+PC peak amplitude ratio in the tumors under consideration. MPM analysis also revealed the presence of two different inorganic phosphate pools: a larger acidic pool and a smaller alkaline pool during estrogen-induced growth and the reverse during tumor regression.

  8. Distance measurements in disodium ATP hydrates by means of 31P double quantum two-dimensional solid-state NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Potrzebowski, M. J.; Gajda, J.; Ciesielski, W.; Montesinos, I. M.

    2006-04-01

    POST-C7 measurements provide constraints allowing distinguishing crystal lattice organization and establishing intra and/or intermolecular distances between phosphorus atoms of triphosphate chains for different hydrates of disodium ATP salts. Double-quantum efficiency in function of excitation time obtained from series of two-dimensional spectra for POST-C7 experiments was used to set up of buildup curves and semi-quantitative measure of 31P- 31P length.

  9. HPLC and 31P NMR characterization of the reaction between antitumor platinum agents and the phosphorothioate chemoprotective agent S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721).

    PubMed

    Thompson, D C; Wyrick, S D; Holbrook, D J; Chaney, S G

    1995-10-26

    In prior studies, we examined the effects of the radioprotective and chemoprotective agent WR-2721 [S-2-(3-aminopropylamino)ethylphosphorothioic acid] on the in vivo biotransformation of the cisplatin [cis-diamminedichloroplatinum(II)] analog ormaplatin [(d,I)trans-1,2-diaminocyclohexanetetrachloroplatinum(IV), Pt(dach)Cl4, (formerly called tetraplatin)]. Those data suggested that a direct interaction between WR-2721 and ormaplatin and/or the corresponding Pt(II) drug, Pt(dach)Cl2, may be occurring in vivo. This would be in contrast to the generally accepted hypothesis that WR-2721 is a prodrug that must first be converted by alkaline phosphatase to a free thiol compound, WR-1065, before any appreciable reactivity would be evident. However, the major biotransformation product observed in the peritoneal fluid, plasma, and all tissues was Pt(dach)(WR-1065). We report here on further investigations into the in vitro reactivity of Pt(dach) compounds with WR-2721 and WR-1065. Separation of reaction products resulting from incubation of Pt(dach)(malonato) with either WR-2721 or WR-1065 under physiological conditions gave profiles that were indistinguishable by reverse phase HPLC and cation exchange HPLC at two different pHs. 31P NMR characterization of the dephosphorylation of WR-2721 revealed essentially no loss of inorganic phosphate for up to 24 hr when incubated in unbuffered water at 30 degrees. In contrast, when incubated with a 1:1 molar ratio of cisplatin under the same conditions, the WR-2721 signal was decreased markedly in the first 5 min, and had disappeared almost completely by 1 hr. The signal corresponding to inorganic phosphate increased in parallel to the decrease in the WR-2721 signal. No intermediate formation of a complex containing both platinum and phosphate could be detected at any time. These data suggest that the reaction between WR-2721 and platinum complexes results in rapid dephosphorylation of WR-2721, and, consequently, that the reaction

  10. Interaction Study of an Amorphous Solid Dispersion of Cyclosporin A in Poly-Alpha-Cyclodextrin with Model Membranes by 1H-, 2H-, 31P-NMR and Electron Spin Resonance

    PubMed Central

    Debouzy, Jean-Claude; Bourbon, Fréderic; Lahiani-Skiba, Malika; Skiba, Mohamed

    2014-01-01

    The properties of an amorphous solid dispersion of cyclosporine A (ASD) prepared with the copolymer alpha cyclodextrin (POLYA) and cyclosporine A (CYSP) were investigated by 1H-NMR in solution and its membrane interactions were studied by 1H-NMR in small unilamellar vesicles and by 31P 2H NMR in phospholipidic dispersions of DMPC (dimyristoylphosphatidylcholine) in comparison with those of POLYA and CYSP alone. 1H-NMR chemical shift variations showed that CYSP really interacts with POLYA, with possible adduct formation, dispersion in the solid matrix of the POLYA, and also complex formation. A coarse approach to the latter mechanism was tested using the continuous variations method, indicating an apparent 1 : 1 stoichiometry. Calculations gave an apparent association constant of log Ka = 4.5. A study of the interactions with phospholipidic dispersions of DMPC showed that only limited interactions occurred at the polar head group level (31P). Conversely, by comparison with the expected chain rigidification induced by CYSP, POLYA induced an increase in the fluidity of the layer while ASD formation led to these effects almost being overcome at 298 K. At higher temperature, while the effect of CYSP seems to vanish, a resulting global increase in chain fluidity was found in the presence of ASD. PMID:24883210

  11. Muscle energetics changes throughout maturation: a quantitative 31P-MRS analysis

    PubMed Central

    Tonson, Anne; Ratel, Sébastien; Le Fur, Yann; Vilmen, Christophe; Cozzone, Patrick J.

    2010-01-01

    We quantified energy production in 7 prepubescent boys (11.7 ± 0.6 yr) and 10 men (35.6 ± 7.8 yr) using 31P-magnetic resonance spectroscopy to investigate whether development affects muscle energetics, given that resistance to fatigue has been reported to be larger before puberty. Each subject performed a finger flexions exercise at 0.7 Hz against a weight adjusted to 15% of their maximal voluntary strength for 3 min, followed by a 15-min recovery period. The total energy cost was similar in both groups throughout the exercise bout, whereas the interplay of the different metabolic pathways was different. At the onset of exercise, children exhibited a higher oxidative contribution (50 ± 15% in boys and 25 ± 8% in men, P < 0.05) to ATP production, whereas the phosphocreatine breakdown contribution was reduced (40 ± 10% in boys and 53 ± 12% in men, P < 0.05), likely as a compensatory mechanism. The anaerobic glycolysis activity was unaffected by maturation. The recovery phase also disclosed differences regarding the rates of proton efflux (6.2 ± 2.5 vs. 3.8 ± 1.9 mM·pH unit−1·min−1, in boys and men, respectively, P < 0.05), and phosphocreatine recovery, which was significantly faster in boys than in men (rate constant of phosphocreatine recovery: 1.3 ± 0.5 vs. 0.7 ± 0.4 min−1; Vmax: 37.5 ± 14.5 vs. 21.1 ± 12.2 mM/min, in boys and men, respectively, P < 0.05). Our results obtained in vivo clearly showed that maturation affects muscle energetics. Children relied more on oxidative metabolism and less on creatine kinase reaction to meet energy demand during exercise. This phenomenon can be explained by a greater oxidative capacity, probably linked to a higher relative content in slow-twitch fibers before puberty. PMID:20847131

  12. Muscle energetics changes throughout maturation: a quantitative 31P-MRS analysis.

    PubMed

    Tonson, Anne; Ratel, Sébastien; Le Fur, Yann; Vilmen, Christophe; Cozzone, Patrick J; Bendahan, David

    2010-12-01

    We quantified energy production in 7 prepubescent boys (11.7 ± 0.6 yr) and 10 men (35.6 ± 7.8 yr) using (31)P-magnetic resonance spectroscopy to investigate whether development affects muscle energetics, given that resistance to fatigue has been reported to be larger before puberty. Each subject performed a finger flexions exercise at 0.7 Hz against a weight adjusted to 15% of their maximal voluntary strength for 3 min, followed by a 15-min recovery period. The total energy cost was similar in both groups throughout the exercise bout, whereas the interplay of the different metabolic pathways was different. At the onset of exercise, children exhibited a higher oxidative contribution (50 ± 15% in boys and 25 ± 8% in men, P < 0.05) to ATP production, whereas the phosphocreatine breakdown contribution was reduced (40 ± 10% in boys and 53 ± 12% in men, P < 0.05), likely as a compensatory mechanism. The anaerobic glycolysis activity was unaffected by maturation. The recovery phase also disclosed differences regarding the rates of proton efflux (6.2 ± 2.5 vs. 3.8 ± 1.9 mM · pH unit(-1) · min(-1), in boys and men, respectively, P < 0.05), and phosphocreatine recovery, which was significantly faster in boys than in men (rate constant of phosphocreatine recovery: 1.3 ± 0.5 vs. 0.7 ± 0.4 min(-1); V(max): 37.5 ± 14.5 vs. 21.1 ± 12.2 mM/min, in boys and men, respectively, P < 0.05). Our results obtained in vivo clearly showed that maturation affects muscle energetics. Children relied more on oxidative metabolism and less on creatine kinase reaction to meet energy demand during exercise. This phenomenon can be explained by a greater oxidative capacity, probably linked to a higher relative content in slow-twitch fibers before puberty. PMID:20847131

  13. Paramagnetic interactions in 31P NMR spectroscopy as a probe for short-range order/disorder of flux-grown rare earth element orthophosphate (monazite/xenotime) solid solutions

    NASA Astrophysics Data System (ADS)

    Palke, A. C.; Stebbins, J. F.; Boatner, L. A.

    2013-12-01

    Many models of inorganic solid solutions relevant to earth scientists start with the assumption of a completely random distribution of substitutional species. This is, in large part, due to the difficulty of obtaining robust experimental confirmation of short-range order/disorder using standard diffraction techniques that provide information about long-range order. Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy has long been used in this capacity, as the technique is characteristically sensitive to variations in local atomic structure around specific NMR-active nuclei. NMR studies of geologically important inorganic materials have historically concentrated on diamagnetic systems in which the complicating effects of unpaired electrons from paramagnetic species (most ions of the transition metals or rare-earth elements) can be ignored. In these diamagnetic materials, variations in small-scale atomic structure in the solid state typically cause shifts in the frequencies of NMR peaks of up to a few tens of ppm. However, NMR spectroscopy is increasingly being applied to inorganic solid solutions in which one of the end members is paramagnetic. In many cases, this leads to the observation of parmagnetically-shifted peaks. Paramagnetic interactions can be much stronger than in ordinary diamagnetic materials and these peaks are typically shifted from tens to thousands of ppm. In this study we present the results of a 31P NMR investigation of a series of flux-grown solid solutions of La1-xCexPO4 ('x' between 0.027 and 0.32) having the monoclinic monazite structure, and of Y1-xMxPO4 (M = Vn+, Ce3+, Nd3+, 'x' between 0.001 and 0.014) having the tetragonal zircon structure. Paramagnetically shifted resonances were observed in the spectra of all samples shifted by up to -204 ppm due to the presence of paramagnetic Vn+, Ce3+, or Nd3+ in the diamagnetic host phase - either LaPO4 or YPO4. Analysis of the spectra and comparison to the crystal structures leads to the

  14. NMR analysis of biodiesel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel is usually analyzed by the various methods called for in standards such as ASTM D6751 and EN 14214. Nuclear magnetic resonance (NMR) is not one of these methods. However, NMR, with 1H-NMR commonly applied, can be useful in a variety of applications related to biodiesel. These include monit...

  15. Multiple Antiferromagnetic Spin Fluctuations and Novel Evolution of Tc in Iron-Based Superconductors LaFe(As1‑xPx)(O1‑yFy) Revealed by 31P-NMR Studies

    NASA Astrophysics Data System (ADS)

    Shiota, Takayoshi; Mukuda, Hidekazu; Uekubo, Masahiro; Engetsu, Fuko; Yashima, Mitsuharu; Kitaoka, Yoshio; Lai, Kwing To; Usui, Hidetomo; Kuroki, Kazuhiko; Miyasaka, Shigeki; Tajima, Setsuko

    2016-05-01

    We report on 31P-NMR studies of LaFe(As1‑xPx)(O1‑yFy) over wide compositions for 0 ≤ x ≤ 1 and 0 ≤ y ≤ 0.14, which provide clear evidence that antiferromagnetic spin fluctuations (AFMSFs) are one of the indispensable elements for enhancing Tc. Systematic 31P-NMR measurements revealed two types of AFMSFs in the temperature evolution, that is, one is the AFMSFs that develop rapidly down to Tc with low-energy characteristics, and the other, with relatively higher energy than the former, develops gradually upon cooling from high temperature. The low-energy AFMSFs in low y (electron doping) over a wide x (pnictogen height suppression) range are associated with the two orbitals of dxz/yz, whereas the higher-energy ones for a wide y region around low x originate from the three orbitals of dxy and dxz/yz. We remark that the nonmonotonic variation of Tc as a function of x and y in LaFe(As1‑xPx)(O1‑yFy) is attributed to these multiple AFMSFs originating from degenerated multiple 3d orbitals inherent to Fe-pnictide superconductors.

  16. 31P NMR 2D Mapping of Creatine Kinase Forward Flux Rate in Hearts with Postinfarction Left Ventricular Remodeling in Response to Cell Therapy

    PubMed Central

    Gao, Ling; Cui, Weina; Zhang, Pengyuan; Jang, Albert; Zhu, Wuqiang; Zhang, Jianyi

    2016-01-01

    Utilizing a fast 31P magnetic resonance spectroscopy (MRS) 2-dimensional chemical shift imaging (2D-CSI) method, this study examined the heterogeneity of creatine kinase (CK) forward flux rate of hearts with postinfarction left ventricular (LV) remodeling. Immunosuppressed Yorkshire pigs were assigned to 4 groups: 1) A sham-operated normal group (SHAM, n = 6); 2) A 60 minutes distal left anterior descending coronary artery ligation and reperfusion (MI, n = 6); 3) Open patch group; ligation injury plus open fibrin patch over the site of injury (Patch, n = 6); and 4) Cell group, hiPSCs-cardiomyocytes, -endothelial cells, and -smooth muscle cells (2 million, each) were injected into the injured myocardium pass through a fibrin patch (Cell+Patch, n = 5). At 4 weeks, the creatine phosphate (PCr)/ATP ratio, CK forward flux rate (Flux PCr→ATP), and k constant of CK forward flux rate (kPCr→ATP) were severely decreased at border zone myocardium (BZ) adjacent to MI. Cell treatment results in significantly increase of PCr/ATP ratio and improve the value of kPCr→ATP and Flux PCr→ATP in BZ myocardium. Moreover, the BZ myocardial CK total activity and protein expression of CK mitochondria isozyme and CK myocardial isozyme were significantly reduced, but recovered in response to cell treatment. Thus, cell therapy results in improvement of BZ bioenergetic abnormality in hearts with postinfarction LV remodeling, which is accompanied by significantly improvements in BZ CK activity and CK isozyme expression. The fast 2D 31P MR CSI mapping can reliably measure the heterogeneity of bioenergetics in hearts with post infarction LV remodeling. PMID:27606901

  17. 31P NMR 2D Mapping of Creatine Kinase Forward Flux Rate in Hearts with Postinfarction Left Ventricular Remodeling in Response to Cell Therapy.

    PubMed

    Gao, Ling; Cui, Weina; Zhang, Pengyuan; Jang, Albert; Zhu, Wuqiang; Zhang, Jianyi

    2016-01-01

    Utilizing a fast 31P magnetic resonance spectroscopy (MRS) 2-dimensional chemical shift imaging (2D-CSI) method, this study examined the heterogeneity of creatine kinase (CK) forward flux rate of hearts with postinfarction left ventricular (LV) remodeling. Immunosuppressed Yorkshire pigs were assigned to 4 groups: 1) A sham-operated normal group (SHAM, n = 6); 2) A 60 minutes distal left anterior descending coronary artery ligation and reperfusion (MI, n = 6); 3) Open patch group; ligation injury plus open fibrin patch over the site of injury (Patch, n = 6); and 4) Cell group, hiPSCs-cardiomyocytes, -endothelial cells, and -smooth muscle cells (2 million, each) were injected into the injured myocardium pass through a fibrin patch (Cell+Patch, n = 5). At 4 weeks, the creatine phosphate (PCr)/ATP ratio, CK forward flux rate (Flux PCr→ATP), and k constant of CK forward flux rate (kPCr→ATP) were severely decreased at border zone myocardium (BZ) adjacent to MI. Cell treatment results in significantly increase of PCr/ATP ratio and improve the value of kPCr→ATP and Flux PCr→ATP in BZ myocardium. Moreover, the BZ myocardial CK total activity and protein expression of CK mitochondria isozyme and CK myocardial isozyme were significantly reduced, but recovered in response to cell treatment. Thus, cell therapy results in improvement of BZ bioenergetic abnormality in hearts with postinfarction LV remodeling, which is accompanied by significantly improvements in BZ CK activity and CK isozyme expression. The fast 2D 31P MR CSI mapping can reliably measure the heterogeneity of bioenergetics in hearts with post infarction LV remodeling. PMID:27606901

  18. Centerband-only analysis of rotor-unsynchronized spin echo for measurement of lipid (31) P chemical shift anisotropy.

    PubMed

    Umegawa, Yuichi; Yamaguchi, Toshiyuki; Murata, Michio; Matsuoka, Shigeru

    2015-07-01

    Structural diversity and molecular flexibility of phospholipids are essential for biological membranes to play key roles in numerous cellular processes. Uncovering the behavior of individual lipids in membrane dynamics is crucial for understanding the molecular mechanisms underlying biological functions of cell membranes. In this paper, we introduce a simple method to investigate dynamics of lipid molecules in multi-component systems by measuring the (31) P chemical shift anisotropy (CSA) under magic angle spinning (MAS) conditions. For achieving both signal separation and CSA determination, we utilized a centerband-only analysis of rotor-unsynchronized spin echo (COARSE). This analysis is based on the curve fitting of periodic modulation of centerband intensity along the interpulse delay time in rotor-unsynchronized spin-echo experiments. The utility of COARSE was examined by using phospholipid vesicles, a three-component lipid raft model system, and archaeal purple membranes. We found that the apparent advantages of this method are high resolution and high sensitivity given by the moderate MAS speed and the one-dimensional acquisition with short spin-echo delays. COARSE provides an alternative method for CSA measurement that is effective in the investigation of lipid polymorphologies.

  19. Effect of prior exercise in Pi/PC ratio and intracellular pH during a standardized exercise. A study on human muscle using [31P]NMR.

    PubMed

    Laurent, D; Authier, B; Lebas, J F; Rossi, A

    1992-01-01

    Seven subjects underwent a standard localized exercise of calf muscles in order to investigate whether the metabolic exercise-induced steady-state, as revealed by the evaluation of inorganic phosphate/phosphocreatine ratio, depends on the conditioning of the muscle just prior to the exercise. The experimental protocols consisted of two separate experiments using first [31P]nuclear magnetic resonance spectroscopy and second (on 3 subjects) infrared oxyphotometry to respectively follow variation of energy metabolism and tissular deoxygenation. The exercise consisted of 240 successive plantar flexions (0.5 Hz frequency) against a high load equivalent to 80% of the maximal voluntary contraction. This exercise was accomplished before cold exercise and after warm exercise, a warming-up period bringing to approximately 50% of VO2max. The results showed that: (1) steady-state level of phosphate/phosphocreatine and intracellular acidosis was significantly lowered by warming-up; (2) cold and warm exercise steady-state of calculated adenosine diphosphate values were not significantly different; (3) cold exercise rapidly induced a high tissular deoxygenation that is not observed during warm exercise; and (4) time-constant of phosphocreatine resynthesis is lowered after warm exercise but the initial slope of time-evolution is not modified. Parallel experiments also showed that phosphate/phosphocreatine steady-state was not modified in comparison with warm exercise when the same power of exercise was reached by stepwise incrementation of the charge. From these results we postulate that a better tissue oxygenation due to a global or localized warming-up allows to reach the same mechanical performance with a lower decrease of PCr content, owing to a faster adjustment of oxidative metabolism during the transitional period.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. A flow-through probe for in Vivo31P NMR spectroscopy of unanesthetized aquatic vertebrates at 9.4 tesla

    NASA Astrophysics Data System (ADS)

    van den Thillart, Guido; Körner, Frans; van Waarde, Aren; Erkelens, Cees; Lugtenburg, Johan

    A flow cell which fits in a modified bioprobe of a Bruker MSL-400 NMR spectrometer and allows the monitoring of the energy metabolism of an enclosed aquatic vertebrate at a selected temperature, water composition, and oxygen level ranging from 0 to 100% air saturation is described. The animal is pressed against the observation window and immobilized by an inflatable plastic bag. No anesthetics are used during the actual experiment. The signal of the tissue of interest is picked up with a surface coil, which is double-tuned to the phosphorus (162 MHz) and proton (400 MHz) frequencies. The flow cell can be moved vertically to the desired position. The usefulness of the fish probe is demonstrated by spectra of excellent resolution and signal-to-noise, obtained from the myotomal muscles of carp, goldfish, rainbow trout, and tilapia, by high phosphocreatine/ inorganic phosphate ratios, indicating a situation of low stress, and by stability of all NMR-observed parameters over periods of at least one working day (8 h).

  1. Effects of temperature and extracellular pH on metabolites: kinetics of anaerobic metabolism in resting muscle by 31P- and 1H-NMR spectroscopy.

    PubMed

    Vezzoli, Alessandra; Gussoni, Maristella; Greco, Fulvia; Zetta, Lucia

    2003-09-01

    Environmental stress, such as low temperature, extracellular acidosis and anoxia, is known to play a key role in metabolic regulation. The aim of the present study was to gain insight into the combined temperature-pH regulation of metabolic rate in frog muscle, i.e. an anoxia-tolerant tissue. The rate of exergonic metabolic processes occurring in resting isolated muscles was determined at 15 degrees C and 25 degrees C as well as at extracellular pH values higher (7.9), similar (7.3) and lower (7.0) than the physiological intracellular pH. (31)P and (1)H nuclear magnetic resonance spectroscopy high-resolution measurements were carried out at 4.7 T in isolated frog (Rana esculenta) gastrocnemius muscle during anoxia to assess, by means of reference compounds, the concentration of all phosphate metabolites and lactate. Intra- and extracellular pH was also determined. In the range of examined temperatures (15-25 degrees C), the temperature dependence of anaerobic glycolysis was found to be higher than that of PCr depletion (Q(10)=2.3). High-energy phosphate metabolism was confirmed to be the initial and preferential energy source. The rate of phosphocreatine hydrolysis did not appear to be affected by extracellular pH changes. By contrast, independent of the intracellular pH value, at the higher temperature (25 degrees C) a lowering of the extracellular pH from 7.9 to 7.0 caused a depression in lactate accumulation. This mechanism was ascribed to the transmembrane proton concentration gradient. This parameter was demonstrated to regulate glycolysis, probably through a reduced lactate efflux, depending on the activity of the lactate-H(+) co-transporter. The calculated intracellular buffer capacity was related to intra- and extracellular pH and temperature. At the experimental extracellular pH of 7.9 and at a temperature of 15 degrees C and 25 degrees C, calculated intracellular buffering capacity was 29.50 micromol g(-1) pH unit(-1) and 69.98 micromol g(-1) pH unit(-1

  2. Hydrothermal synthesis, X-ray structure refinement, 31P NMR spectra and vibrational study of NaLa(HPO4)2

    NASA Astrophysics Data System (ADS)

    Ben Hassen, C.; Boujelbene, M.; Mhiri, T.

    2013-10-01

    NaLa(HPO4)2 was obtained by hydrothermal synthesis. The structure of NaLa(HPO4)2 was determined by X-ray powder diffraction methods. The results of Rietveld refinement revealed a space group P21/c (No. 14), with lattice parameters of a = 9.7151(17) Å, b = 8.320(12) Å, c = 9.83(2) Å, beta = 114.65(17)°, V = 722 (8) Å3 and Z = 4. Final refinement led to RF = 4.86% and RB = 12.35%.The existence of bound O-H and bound P-O in the structure has been confirmed by IR and Raman spectroscopy. The existence of two crystallographically independent phosphorus atoms in the structure has been confirmed by NMR spectrum. The structure is characterized by LaO6 octahedra which are solely connected to six adjacent HPO4 tetrahedra via common O-corners. This structure contains twelve- and four-membered rings forming channels along [1 1¯ 1]. The cross sections of the channels are given by twelve-membered rings consisting of four lanthanum coordination octahedral and eight hydrogenphosphate groups as well as four-membered rings consisting of two lanthanum coordination octahedra and two hydrogenphosphate tetrahedra. Sodium ions are located within those channels of the twelve-membered rings.

  3. Measurement of carbon flux through the MEP pathway for isoprenoid synthesis by (31)P-NMR spectroscopy after specific inhibition of 2-C-methyl-d-erythritol 2,4-cyclodiphosphate reductase. Effect of light and temperature.

    PubMed

    Mongélard, Gaëlle; Seemann, Myriam; Boisson, Anne-Marie; Rohmer, Michel; Bligny, Richard; Rivasseau, Corinne

    2011-08-01

    The methylerythritol 4-phosphate (MEP) and the mevalonate pathways are the unique synthesis routes for the precursors of all isoprenoids. An original mean to measure the carbon flux through the MEP pathway in plants is proposed by using cadmium as a total short-term inhibitor of 2-C-methyl-d-erythritol 2,4-cyclodiphosphate (MEcDP) reductase (GcpE) and measuring the accumulation rate of its substrate MEcDP by (31) P-NMR spectroscopy. The MEP pathway metabolic flux was determined in spinach (Spinacia oleracea), pea (Pisum sativum), Oregon grape (Mahonia aquifolium) and boxwood (Buxus sempervirens) leaves. In spinach, flux values were compared with the synthesis rate of major isoprenoids. The flux increases with light intensity (fourfold in the 200-1200 µmol m(-2) s(-1) PPFR range) and temperature (sevenfold in the 25-37 °C range). The relationship with the light and the temperature dependency of isoprenoid production downstream of the MEP pathway is discussed.

  4. Measurement of the lateral diffusion of dipalmitoylphosphatidylcholine adsorbed on silica beads in the absence and presence of melittin: a 31P two-dimensional exchange solid-state NMR study.

    PubMed Central

    Picard, F; Paquet, M J; Dufourc, E J; Auger, M

    1998-01-01

    31P two-dimensional exchange solid-state NMR spectroscopy was used to measure the lateral diffusion, D(L), in the fluid phase of dipalmitoylphosphatidylcholine (DPPC) in the presence and absence of melittin. The use of a spherical solid support with a radius of 320 +/- 20 nm, on which lipids and peptides are adsorbed together, and a novel way of analyzing the two-dimensional exchange patterns afforded a narrow distribution of D(L) centered at a value of (8.8 +/- 0.5) x 10(-8) cm2/s for the pure lipid system and a large distribution of D(L) spanning 1 x 10(-8) to 10 x 10(-8) cm2/s for the lipids in the presence of melittin. In addition, the determination of D(L) for nonsupported DPPC multilamellar vesicles (MLVs) suggests that the support does not slow down the lipid diffusion and that the radii of the bilayers vary from 300 to 800 nm. Finally, the DPPC-melittin complex is stabilized at the surface of the silica beads in the gel phase, opening the way to further study of the interaction between melittin and DPPC. PMID:9533697

  5. Theoretical Studies on the Fe-M Interactions and 31P NMR in Fe(CO)3(EtPhPpy)2MX2 (X = NCS, SCN, Cl; M = Zn, Cd, Hg)

    NASA Astrophysics Data System (ADS)

    Huang, Xiao-xuan; Xu, Xuan; Xie, Mei-xiang

    2008-10-01

    To study the Fe-M interactions and their effects on 31P NMR, the structures of Fe(CO)3(EtPhPpy)2 1, Fe(CO)3(EtPhPpy)2M(NCS)2 (2: M = Zn, 3: M = Cd, 4: M = Hg) and Fe(CO)3(EtPhPpy)2CdX2 (5: X = C1, 6: X = SCN) were investigated by density functional theory (DFT) PBE0 method. The stabilities S of complexes follow S(2)>S(3)>S(4) and S(3)approxS(6)>S(5), indicating that 6 is stable and may be synthesized. The complexes with thiocyanate are more stable than that with chloride in Fe(CO)3(EtPhPpy)2CdX2. The strength / of Fe-M interactions follows I(2)approxI(3)31P chemical shifts are caused (compared with mononuclear complex 1).

  6. Comparative differential scanning calorimetric and FTIR and 31P-NMR spectroscopic studies of the effects of cholesterol and androstenol on the thermotropic phase behavior and organization of phosphatidylcholine bilayers.

    PubMed Central

    McMullen, T. P.; Lewis, R. N.; McElhaney, R. N.

    1994-01-01

    We have investigated the comparative effects of the incorporation of increasing quantities of androstenol and cholesterol on the thermotropic phase behavior of aqueous dispersions of members of a homologous series of linear saturated diacyl PCs1 using high sensitivity DSC. We have also employed FTIR and 31P-NMR spectroscopy to study the comparative effects of androstenol and cholesterol incorporation on the organization of the host PC bilayer in both the gel and liquid-crystalline states. The effects of androstenol and cholesterol incorporation on the thermotropic phase behavior of shorter chain PCs like 14:0 PC are generally similar but not identical. The incorporation of either sterol progressively decreases the temperature and enthalpy, but not the cooperativity, of the pretransition and completely abolishes it at sterol concentrations above 5 mol%. Moreover, at sterol concentrations of 1 to 20-25 mol%, both androstenol and cholesterol incorporation produce DSC endotherms consisting of superimposed sharp and broad components, the former due to the hydrocarbon chain melting of sterol-poor and the latter to the melting of sterol-rich 14:0 PC domains. The temperature and cooperativity of the sharp component are reduced slightly with increasing concentration of androstenol or cholesterol, and the enthalpy of the sharp component decreases progressively and becomes zero at 20-25 mol% sterol. As well, at cholesterol or androstenol concentrations above 20-25 mol%, the enthalpy of the broad component also decreases linearly with increasing sterol incorporation and becomes zero at sterol levels of about 50 mol%. However, whereas cholesterol incorporation progressively increases the temperature of the broad component of the DSC endotherm, androstenol incorporation decreases the temperature of this component. In contrast, the effects of androstenol and cholesterol incorporation on the thermotropic phase behavior of the intermediate and longer chain PCs studied here are

  7. Neither moderate hypoxia nor mild hypoglycaemia alone causes any significant increase in cerebral [Ca2+]i: only a combination of the two insults has this effect. A 31P and 19F NMR study.

    PubMed

    Badar-Goffer, R S; Thatcher, N M; Morris, P G; Bachelard, H S

    1993-12-01

    (1) The energy state and free intracellular calcium concentration ([Ca2+]i) of superfused cortical slices were measured in moderate hypoxia (approximately 65 microM O2), in mild hypoglycaemia (0.5 mM glucose), and in combinations of the two insults using 19F and 31P NMR spectroscopy. (2) Neither hypoxia nor hypoglycaemia alone caused any significant change in [Ca2+]i. Hypoxia caused a 40% fall in phosphocreatine (PCr) content but not in ATP level, and hypoglycaemia produced a slight fall in both (as expected from previous studies). These changes in the energy state recovered on return to control conditions. (3) A combined sequential insult (hypoxia, followed by hypoxia plus hypoglycaemia) produced a 100% increase in [Ca2+]i and a decrease in PCr level to approximately 25% of control. The reverse combined sequential insult (hypoglycaemia, followed by hypoglycaemia plus hypoxia) had the same effect. On return to control conditions there was some decrease in [Ca2+]i and a small increase in PCr content, but neither recovered to control levels. (4) Exposure of the tissue to the combined simultaneous insult (hypoxia plus hypoglycaemia) immediately after the control spectra had been recorded resulted in a fivefold increase in [Ca2+]i and a similar decrease in PCr level to 20-25% of control. There was little if any change of [Ca2+]i or PCr level on return to control conditions. (5) These results are discussed in terms of metabolic adaptation of some but not all of the cortical cells to the single type of insult, which renders the tissues less vulnerable to the combined insult.

  8. Identification by stopped-exchange solution /sup 31/P NMR spectroscopy of the stepwise formation of (AgL/sub n/)PF/sub 6/ (n = 1-4). Comparison of metal-phosphorus coupling constants for triphenylphosphine and 5-phenyldibenzophosphole

    SciTech Connect

    Alyea, E.C.; Malito, J.; Nelson, J.H.

    1987-12-16

    The coordination properties of 5-phenyldibenzophosphate (PhDBP) have been studied extensively. The stepwise formation of (L/sub n/Ag)/sup +/PF/sub 6//sup -/ (n = 1-4) for L = PhDBP and PhP/sub 3/ observed in situ by stopped-exchange solution /sup 31/P NMR spectroscopy is reported herein. The relative coordinating properties of PhDBP and PhP/sub 3/ are compared. 21 references, 1 figure, 2 tables.

  9. Comparative analysis of skeletal muscle oxidative capacity in children and adults: a 31P-MRS study.

    PubMed

    Ratel, Sébastien; Tonson, Anne; Le Fur, Yann; Cozzone, Patrick; Bendahan, David

    2008-08-01

    The aim of the present study was to compare the oxidative capacity of the forearm flexor muscles in vivo between children and adults using 31-phosphorus magnetic resonance spectroscopy. Seven boys (11.7 +/- 0.6 y) and 10 men (35.6 +/- 7.8 year) volunteered to perform a 3 min dynamic finger flexions exercise against a standardized weight (15% of the maximal voluntary contraction). Muscle oxidative capacity was quantified on the basis of phosphocreatine (PCr) post-exercise recovery kinetics analysis. End-of-exercise pH was not significantly different between children and adults (6.6 +/- 0.2 vs. 6.5 +/- 0.2), indicating that indices of PCr recovery kinetics can be reliably compared. The rate constant of PCr recovery (kPCr) and the maximum rate of aerobic ATP production were about 2-fold higher in young boys than in men (kPCr: 1.7 +/- 1.2 vs. 0.7 +/- 0.2 min(-1); Vmax: 49.7 +/- 24.6 vs. 29.4 +/- 7.9 mmol.L(-1).min(-1), p < 0.05). Our results clearly illustrate a greater mitochondrial oxidative capacity in the forearm flexor muscles of young children. This larger ATP regeneration capacity through aerobic mechanisms in children could be one of the factors accounting for their greater resistance to fatigue during high-intensity intermittent exercise. PMID:18641715

  10. A New Microcell Technique for NMR Analysis.

    ERIC Educational Resources Information Center

    Yu, Sophia J.

    1987-01-01

    Describes a new laboratory technique for working with small samples of compounds used in nuclear magnetic resonance (NMR) analysis. Demonstrates how microcells can be constructed for each experiment and samples can be recycled. (TW)

  11. sup 31 P and sup 1 H NMR studies of the structure of enzyme-bound substrate complexes of lobster muscle arginine kinase: Relaxation measurements with Mn(II) and Co(II)

    SciTech Connect

    Jarori, G.K.; Ray, B.D.; Rao, B.D.N. )

    1989-11-28

    The paramagnetic effects of Mn(II) and Co(II) on the spin-lattice relaxation rates of {sup 31}P nuclei of ATP and ADP and of Mn(II) on the spin-lattice relaxation rate of the {delta} protons of arginine bound to arginine kinase from lobster tail muscle have been measured. Temperature variation of {sup 31}P relaxation rates in E-MnADP and E-MnATP yields activation energies ({Delta}E) in the range 6-10 kcal/mol. Thus, the {sup 31}P relaxation rates in these complexes are exchange limited and cannot provide structural information. However, the relaxation rates in E-CoADP and E-CoATP exhibit frequency dependence and {Delta}E values in the range 1-2 kcal/mol; i.e., these rates depend upon {sup 31}P-Co(II) distances. These distances were calculated to be in the range 3.2-4.5 {angstrom}, appropriate for direct coordination between Co(II) and the phosphoryl groups. The paramagnetic effect of Mn(II) on the {sup 1}H spin-lattice relaxation rate of the {delta} protons of arginine in the E-MnADP-Arg complex was also measured at three frequencies. From the frequency dependence of the relaxation rate an effective {tau}{sub C} of 0.6 ns has also been calculated, which is most likely to be the electron spin relaxation rate ({tau}{sub S1}) for Mn(II) in this complex. The distance estimated on the basis of the reciprocal sixth root of the average relaxation rate of the {delta} protons was 10.9 {plus minus} 0.3 {angstrom}.

  12. Solution (31)P NMR Study of the Acid-Catalyzed Formation of a Highly Charged {U24Pp12} Nanocluster, [(UO2)24(O2)24(P2O7)12](48-), and Its Structural Characterization in the Solid State Using Single-Crystal Neutron Diffraction.

    PubMed

    Dembowski, Mateusz; Olds, Travis A; Pellegrini, Kristi L; Hoffmann, Christina; Wang, Xiaoping; Hickam, Sarah; He, Junhong; Oliver, Allen G; Burns, Peter C

    2016-07-13

    The first neutron diffraction study of a single crystal containing uranyl peroxide nanoclusters is reported for pyrophosphate-functionalized Na44K6[(UO2)24(O2)24(P2O7)12][IO3]2·140H2O (1). Relative to earlier X-ray studies, neutron diffraction provides superior information concerning the positions of H atoms and lighter counterions. Hydrogen positions have been assigned and reveal an extensive network of H-bonds; notably, most O atoms present in the anionic cluster accept H-bonds from surrounding H2O molecules, and none of the surface-bound O atoms are protonated. The D4h symmetry of the cage is consistent with the presence of six encapsulated K cations, which appear to stabilize the lower symmetry variant of this cluster. (31)P NMR measurements demonstrate retention of this symmetry in solution, while in situ (31)P NMR studies suggest an acid-catalyzed mechanism for the assembly of 1 across a wide range of pH values.

  13. Quantitative analysis of ³¹P NMR spectra of soil extracts--dealing with overlap of broad and sharp signals.

    PubMed

    Doolette, Ashlea L; Smernik, Ronald J

    2015-09-01

    Solution (31)P NMR analysis following extraction with a mixture of sodium hydroxide and ethylenediaminetetraacetic acid is the most widely used method for detailed characterization of soil organic P. However, quantitative analysis of the (31)P NMR spectra is complicated by severe spectral overlap in the monoester region. Various deconvolution procedures have been developed for the task, yet none of these are widely accepted or implemented. In this mini-review, we first describe and compare these varying approaches. We then review approaches to similar issues of spectral overlap in biomedical science applications including NMR-based metabolic profiling and analyzing (31)P magnetic resonance spectra of ex vivo and in vivo intact tissues. The greater maturity and resourcing of this biomedical research means that a wider variety of approaches has been developed. Of particular relevance are approaches to dealing with overlap of broad and sharp signals. Although the existence of this problem is still debated in the context of soil analyses, not only is it well-recognized in biomedical applications, but multiple approaches have been developed to deal with it, including T2 editing and time-domain fitting. Perhaps the most transferable concept is the incorporation of 'prior knowledge' in the fitting of spectra. This is well established in biomedical applications but barely touched in soil analyses. We argue that shortcuts to dealing with overlap in the monoester region (31)P NMR soil spectra are likely to be found in the biomedical literature, although some degree of adaptation will be necessary. PMID:25854619

  14. Quantitative analysis of ³¹P NMR spectra of soil extracts--dealing with overlap of broad and sharp signals.

    PubMed

    Doolette, Ashlea L; Smernik, Ronald J

    2015-09-01

    Solution (31)P NMR analysis following extraction with a mixture of sodium hydroxide and ethylenediaminetetraacetic acid is the most widely used method for detailed characterization of soil organic P. However, quantitative analysis of the (31)P NMR spectra is complicated by severe spectral overlap in the monoester region. Various deconvolution procedures have been developed for the task, yet none of these are widely accepted or implemented. In this mini-review, we first describe and compare these varying approaches. We then review approaches to similar issues of spectral overlap in biomedical science applications including NMR-based metabolic profiling and analyzing (31)P magnetic resonance spectra of ex vivo and in vivo intact tissues. The greater maturity and resourcing of this biomedical research means that a wider variety of approaches has been developed. Of particular relevance are approaches to dealing with overlap of broad and sharp signals. Although the existence of this problem is still debated in the context of soil analyses, not only is it well-recognized in biomedical applications, but multiple approaches have been developed to deal with it, including T2 editing and time-domain fitting. Perhaps the most transferable concept is the incorporation of 'prior knowledge' in the fitting of spectra. This is well established in biomedical applications but barely touched in soil analyses. We argue that shortcuts to dealing with overlap in the monoester region (31)P NMR soil spectra are likely to be found in the biomedical literature, although some degree of adaptation will be necessary.

  15. Characterizing phosphorus in environmental and agricultural samples by 31P nuclear magnetic resonance spectroscopy.

    PubMed

    Cade-Menun, Barbara J

    2005-04-15

    Phosphorus nuclear magnetic resonance ((31)P-NMR) spectroscopy has advanced our knowledge of organic phosphorus (P) in soils and environmental samples more than any other technique. This paper reviews the use of (31)P-NMR spectroscopy for soil, water and other environmental samples. The requirements for a successful solid-state or solution (31)P-NMR experiment are described, including experimental set-up, sample preparation, extractants, experimental conditions, and post-experimental processing. Next, the literature on solid-state and solution (31)P-NMR spectroscopy in environmental samples is reviewed, including papers on: methods; P transformations; agricultural, forest and natural ecosystem soil studies; humic acid and particle size separations; manure, compost and sludge studies; and water research, including freshwater, estuary and marine studies. Future research needs are also discussed as well as suggestions to improve results, such as increased standardization among research groups.

  16. Improving the Hyperpolarization of 31P Nuclei by Synthetic Design

    PubMed Central

    2015-01-01

    Traditional 31P NMR or MRI measurements suffer from low sensitivity relative to 1H detection and consequently require longer scan times. We show here that hyperpolarization of 31P nuclei through reversible interactions with parahydrogen can deliver substantial signal enhancements in a range of regioisomeric phosphonate esters containing a heteroaromatic motif which were synthesized in order to identify the optimum molecular scaffold for polarization transfer. A 3588-fold 31P signal enhancement (2.34% polarization) was returned for a partially deuterated pyridyl substituted phosphonate ester. This hyperpolarization level is sufficient to allow single scan 31P MR images of a phantom to be recorded at a 9.4 T observation field in seconds that have signal-to-noise ratios of up to 94.4 when the analyte concentration is 10 mM. In contrast, a 12 h 2048 scan measurement under standard conditions yields a signal-to-noise ratio of just 11.4. 31P-hyperpolarized images are also reported from a 7 T preclinical scanner. PMID:25811635

  17. NMR methodologies in the analysis of blueberries.

    PubMed

    Capitani, Donatella; Sobolev, Anatoly P; Delfini, Maurizio; Vista, Silvia; Antiochia, Riccarda; Proietti, Noemi; Bubici, Salvatore; Ferrante, Gianni; Carradori, Simone; De Salvador, Flavio Roberto; Mannina, Luisa

    2014-06-01

    An NMR analytical protocol based on complementary high and low field measurements is proposed for blueberry characterization. Untargeted NMR metabolite profiling of blueberries aqueous and organic extracts as well as targeted NMR analysis focused on anthocyanins and other phenols are reported. Bligh-Dyer and microwave-assisted extractions were carried out and compared showing a better recovery of lipidic fraction in the case of microwave procedure. Water-soluble metabolites belonging to different classes such as sugars, amino acids, organic acids, and phenolic compounds, as well as metabolites soluble in organic solvent such as triglycerides, sterols, and fatty acids, were identified. Five anthocyanins (malvidin-3-glucoside, malvidin-3-galactoside, delphinidin-3-glucoside, delphinidin-3-galactoside, and petunidin-3-glucoside) and 3-O-α-l-rhamnopyranosyl quercetin were identified in solid phase extract. The water status of fresh and withered blueberries was monitored by portable NMR and fast-field cycling NMR. (1) H depth profiles, T2 transverse relaxation times and dispersion profiles were found to be sensitive to the withering.

  18. A Solid-State NMR Experiment: Analysis of Local Structural Environments in Phosphate Glasses

    ERIC Educational Resources Information Center

    Anderson, Stanley E.; Saiki, David; Eckert, Hellmut; Meise-Gresch, Karin

    2004-01-01

    An experiment that can be used to directly study the local chemical environments of phosphorus in solid amorphous materials is demonstrated. The experiment aims at familiarizing the students of chemistry with the principles of solid-state NMR, by having them synthesize a simple phosphate glass, and making them observe the (super 31)P NMR spectrum,…

  19. Synthesis and sup 31 P NMR spectroscopy of trinuclear, phosphido-bridged iridium and rhodium clusters. Crystal and molecular structures of (M sub 3 (. mu. -PPh sub 2 ) sub 3 (CO) sub n L sub 2 ) (M = Ir or Rh, n = 3, L sub 2 = bis(diphenylphosphino)methane: M = Ir, n = 5, L = t-BuNC)

    SciTech Connect

    Berry, D.E.; Browning, J.; Dehghan, K.; Dixon, K.R.; Meanwell, N.J.; Phillips, A.J. )

    1991-02-06

    Reaction of (Ir{sub 2}(cyclooctene){sub 4}Cl{sub 2}) with CO, NHEt{sub 2}, and PHPh{sub 2} provides a synthetic route to the trinuclear, phosphido-bridged iridium clusters (Ir{sub 3}({mu}-PPh{sub 2}){sub 3}(CO){sub n}L{sub 2}) (n = 3, L = CO or PPh{sub 3}, L{sub 2} = bis(diphenylphosphino)methane (dppm); n = 5, L = t-BuNC). The CO and PPh{sub 3} complexes are analogues of previously known rhodium derivatives, and rhodium analogues of the dppm and t-BuNC complexes are also reported. The crystal structure of both the Ir and Rh complexes was determined and are reported. The molecular structure was also determined. Complete analyses of the {sup 31}P NMR spectra of the prepared complexes are also reported.

  20. NMR analysis of a fluorocarbon copolymer

    SciTech Connect

    Smith, R.E.; Smith, C.H.

    1987-10-01

    Vinylidene fluoride (VF/sub 2/) can be copolymerized with chlorotrifluoroethylene (CTFE) in an aqueous emulsion using a peroxide chain initiator. The physical properties of the resulting fluorocarbon polymer depend on the ratio of VF/sub 2/ to CTFE and the randomness of the copolymerization. When CTFE and VF are polymerized in an approximately 3:1 mole ratio, the resulting polymer is soluble in acetone (and other solvents) at room temperature. Using proton and fluorine-19 NMR, the mole ratio of CTFE to VF/sub 2/, the emulsifier (perfluorodecanoate) concentration, and the randomness of copolymerization can be determined. A trifluorotoluene internal standard is added to a d/sub 6/-acetone solution of the fluoropolymer. Proton NMR is used to determine the amount of VF/sub 2/. Fluorine-19 NMR is used to measure the amount of emulsifier and the randomness of copolymerization. Each analysis requires about 5 minutes, and is quite precise, with relative standard deviations from 3 to 10% (10 replicates analyzed). In addition, the results from NMR analyses agree well with wet chemical analyses. 4 refs., 3 figs., 3 tabs.

  1. Phosphorus speciation by (31)P NMR spectroscopy in bracken (Pteridium aquilinum (L.) Kuhn) and bluebell (Hyacinthoides non-scripta (L.) Chouard ex Rothm.) dominated semi-natural upland soil.

    PubMed

    Ebuele, Victor O; Santoro, Anna; Thoss, Vera

    2016-10-01

    Access to P species is a driver for plant community composition based on nutrient acquisition. Here we investigated the distribution and accumulation of soil inorganic P (Pi) and organic P (Po) forms in a bracken and bluebell dominated upland soil for the period between bluebell above ground dominance until biomass is formed from half bluebells and half bracken. Chemical characterisation and (31)P Nuclear Magnetic Resonance spectroscopy was used to determine the organic and inorganic P species. Total P concentration in soils was 0.87gkg(-1), while in plants (above- and below-ground parts) total P ranged between 0.84-4.0gkg(-1) and 0.14-2.0gkg(-1) for bluebell and bracken, respectively. The P speciation in the plant samples was reflected in the surrounding soil. The main forms of inorganic P detected in the NaOH-EDTA soil extracts were orthophosphate (20.0-31.5%), pyrophosphate (0.6-2.5%) and polyphosphate (0.4-7.0%). Phytate (myo-IP6) was the most dominant organic P form (23.6-40.0%). Other major peaks were scyllo-IP6 and α- and β- glycerophosphate (glyP). In bluebells and bracken the main P form detected was orthophosphate ranging from (21.7-80.4%) and 68.5-81.1%, in above-ground and below-ground biomass, respectively. Other detected forms include α-glyP (4.5-14.4%) and β-glyP (0.9-7.7%) in bluebell, while in bracken they were detected only in stripe and blade in ranges of 2.5-5.5% and 4.4-9.6%, respectively. Pyrophosphate, polyphosphate, scyllo-IP6, phosphonates, found in soil samples, were not detected in any plant parts. In particular, the high abundance of phytate in the soil and in bluebell bulbs, may be related to a mechanism through which bluebells create a recalcitrant phosphorus store which form a key part of their adaptation to nutrient poor conditions.

  2. 31-P NMR studies of intracellular pH (pH/sub i/) of the in vitro resting rat diaphragm (D) exposed to hypercapnia (HC), plus amiloride (HCA)

    SciTech Connect

    Fitzgerald, R.; Howell, S.; Jacobus, W.

    1986-03-05

    The authors have previously reported that the pH/sub i/ of the resting rat D in vitro fell when exposed to HC. Since pH/sub i/ influences cellular functions, it is important to understand mechanisms whereby a tissue maintains its pH/sub i/ One mechanism reported to exist in some vertebrate tissues is a sodium-proton pump which is inhibited by amiloride. If the rat D had the Na/sup +/-H/sup +/ pump, the resting rat D pH/sub i/, when exposed to hypercapnia, would decrease more if amiloride was present than if there was no amiloride. The D was placed in a 25 mm NMR sample tube and superfused with buffer gassed with 95%O/sub 2/-5%CO/sub 2/ at 37/sup 0/C. Two 15 minute pulsed Fourier transform spectra were acquired at 72.89 MHz using 2 sec repetition rate during normocapnia. The D was next superfused for 60 minutes with buffer gassed with 80%O/sub 2/-20%CO/sub 2/ and containing 5 x 10/sup -4/M amiloride (n=5; HCA) or not (n=8; HC). Four 15 minute spectra were obtained; pH/sub i/ was determined from the chemical shift of P/sub i/ resonance. The pH/sub i/ (X vector +/- SE) of HC D's fell from 7.14 +/- .04 to 6.85 +/- .05 at 1 hour of exposure. The pH/sub i/ of HCA D's fell from 6.95 +/- .05 to 6.57 +/- .03. The decrease in pH/sub i/ during hypercapnia is significantly greater (P<0.01) for HCA D's. These data suggest that the rat D uses a Na/sup +/-H/sup +/ pump to regulate pH/sub i/ and that this pump operates in the in vitro resting rat D exposed to hypercapnia.

  3. Two-Dimensional NMR Lineshape Analysis

    PubMed Central

    Waudby, Christopher A.; Ramos, Andres; Cabrita, Lisa D.; Christodoulou, John

    2016-01-01

    NMR titration experiments are a rich source of structural, mechanistic, thermodynamic and kinetic information on biomolecular interactions, which can be extracted through the quantitative analysis of resonance lineshapes. However, applications of such analyses are frequently limited by peak overlap inherent to complex biomolecular systems. Moreover, systematic errors may arise due to the analysis of two-dimensional data using theoretical frameworks developed for one-dimensional experiments. Here we introduce a more accurate and convenient method for the analysis of such data, based on the direct quantum mechanical simulation and fitting of entire two-dimensional experiments, which we implement in a new software tool, TITAN (TITration ANalysis). We expect the approach, which we demonstrate for a variety of protein-protein and protein-ligand interactions, to be particularly useful in providing information on multi-step or multi-component interactions. PMID:27109776

  4. Analysis of canonical molecular orbitals to identify fermi contact coupling pathways. 1. Through-space transmission by overlap of (31)P lone pairs.

    PubMed

    Contreras, Rubén H; Gotelli, Gustavo; Ducati, Lucas C; Barbosa, Thais M; Tormena, Cláudio F

    2010-01-21

    In this work, a new approach to studying coupling pathways for the Fermi contact term of NMR spin-spin coupling constants (SSCCs) is presented. It is based on the known form of propagating the Fermi hole through a canonical molecular orbital (CMO). It requires having an adequate spatial description of the relevant canonical molecular orbitals, which are obtained by expanding CMOs in terms of natural bond orbitals (NBOs). For detecting the relevant contributions of CMOs to a given Fermi contact (FC) pathway, the description of the FC in terms of the triplet polarization propagator (PP) is used. To appreciate the potential of this approach, dubbed FCCP-CMO (Fermi contact coupling pathways-CMO), it is applied to analyze the through-space transmission of the FC term of J(PP) SSCCs by overlap of the P lone pairs. This method can be applied using well-known quantum chemistry software without any further modification, which makes it appealing for use as a complement to SSCC measurements by NMR spectroscopy.

  5. Complex Mixture Analysis of Organic Compounds in Yogurt by NMR Spectroscopy.

    PubMed

    Lu, Yi; Hu, Fangyu; Miyakawa, Takuya; Tanokura, Masaru

    2016-01-01

    NMR measurements do not require separation and chemical modification of samples and therefore rapidly and directly provide non-targeted information on chemical components in complex mixtures. In this study, one-dimensional (¹H, (13)C, and (31)P) and two-dimensional (¹H-(13)C and ¹H-(31)P) NMR spectroscopy were conducted to analyze yogurt without any pretreatment. ¹H, (13)C, and (31)P NMR signals were assigned to 10 types of compounds. The signals of α/β-lactose and α/β-galactose were separately observed in the ¹H NMR spectra. In addition, the signals from the acyl chains of milk fats were also successfully identified but overlapped with many other signals. Quantitative difference spectra were obtained by subtracting the diffusion ordered spectroscopy (DOSY) spectra from the quantitative ¹H NMR spectra. This method allowed us to eliminate interference on the overlaps; therefore, the correct intensities of signals overlapped with those from the acyl chains of milk fat could be determined directly without separation. Moreover, the ¹H-(31)P HMBC spectra revealed for the first time that N-acetyl-d-glucosamine-1-phosphate is contained in yogurt. PMID:27322339

  6. Complex Mixture Analysis of Organic Compounds in Yogurt by NMR Spectroscopy

    PubMed Central

    Lu, Yi; Hu, Fangyu; Miyakawa, Takuya; Tanokura, Masaru

    2016-01-01

    NMR measurements do not require separation and chemical modification of samples and therefore rapidly and directly provide non-targeted information on chemical components in complex mixtures. In this study, one-dimensional (1H, 13C, and 31P) and two-dimensional (1H-13C and 1H-31P) NMR spectroscopy were conducted to analyze yogurt without any pretreatment. 1H, 13C, and 31P NMR signals were assigned to 10 types of compounds. The signals of α/β-lactose and α/β-galactose were separately observed in the 1H NMR spectra. In addition, the signals from the acyl chains of milk fats were also successfully identified but overlapped with many other signals. Quantitative difference spectra were obtained by subtracting the diffusion ordered spectroscopy (DOSY) spectra from the quantitative 1H NMR spectra. This method allowed us to eliminate interference on the overlaps; therefore, the correct intensities of signals overlapped with those from the acyl chains of milk fat could be determined directly without separation. Moreover, the 1H-31P HMBC spectra revealed for the first time that N-acetyl-d-glucosamine-1-phosphate is contained in yogurt. PMID:27322339

  7. Posttranslational modification of Klebsiella pneumoniae flavodoxin by covalent attachment of coenzyme A, shown by sup 31 P NMR and electrospray mass spectrometry, prevents electron transfer from the nifJ protein to nitrogenase. A possible new regulatory mechanism for biological nitrogen fixation

    SciTech Connect

    Thorneley, R.N.F.; Ashby, G.A.; Drummond, M.H.; Eady, R.R.; Huff, S.; Macdonald, C.J. ); Abell, C.; Schneier, A. )

    1992-02-04

    A strain of Escherichia coli (71-18) that produces ca. 15% of its soluble cytoplasmic protein as a flavodoxin, the Klebsiella pneumoniae nifF gene product, has been constructed. The flavodoxin was purified using FPLC and resolved into two forms, designated KpFldI and KpFldII, which were shown to have identical N-terminal amino acid sequences (30 residues) in agreement with that predicted by the K. pneumoniae nifF DNA sequence. {sup 31}P NMR, electrospray mass spectrometry, UV-visible spectra, and thiol group estimations showed that the single cysteine residue (position 68) of KpFldI is posttranslationally modified in KpFldII by the covalent, mixed disulfide, attachment of coenzyme A. KpFldII was inactive as an electron carrier between the K. pneumoniae nifJ product (a pyruvate-flavodoxin oxidoreductase) and K. pneumoniae nifH product (the Fe-protein of nitrogenase). This novel posttranslational modification of a flavodoxin is discussed in terms of the regulation of nitrogenase activity in vivo in response to the level of dissolved O{sub 2} and the carbon status of diazotrophic cultures.

  8. /195/Pt(/sup 1/H) and /sup 31/P(/sup 1/H) NMR investigation of the platinum(0)-tetraphosphine complexes Pt(CH/sub 3/C(CH/sub 2/PPh/sub 2/)/sub 3/)PR/sub 3/

    SciTech Connect

    Green, L.M.; Youngae Park; Meek, D.W.

    1988-05-04

    Preparation of a series of dissociatively stable Pt(tripod)PR/sub 3/ complexes where tripod = CH/sub 3/C(CH/sub 2/PPh/sub 2/)/sub 3/ and PR/sub 3/ = PMe/sub 2/Ph, PMePh/sub 2/, PPh/sub 3/, P(4FC/sub 6/H/sub 4/)/sub 3/, P(3,5(CF/sub 3/)/sub 2/C/sub 6/H/sub 3/)/sub 3/, P(CH/sub 2/CH/sub 2/CN)/sub 3/, P(OMe)Ph/sub 2/, P(OMe)/sub 2/Ph, P(OMe)/sub 3/, P(POh)/sub 3/, and P(OCH/sub 2/CF/sub 3/)/sub 3/ are reported. /sup 195/Pt(/sup 1/H) and /sup 31/P(/sup 1/H) NMR data are also included. These data have expanded the data base available for the platinum (0) complexes and facilitated the drawing of empirical relationships from the platinum chemical shifts and platinum-phosphorus coupling constants. 29 refs., 1 fig., 1 tab.

  9. Quantification of in vivo ³¹P NMR brain spectra using LCModel.

    PubMed

    Deelchand, Dinesh Kumar; Nguyen, Tra-My; Zhu, Xiao-Hong; Mochel, Fanny; Henry, Pierre-Gilles

    2015-06-01

    Quantification of (31)P NMR spectra is commonly performed using line-fitting techniques with prior knowledge. Currently available time- and frequency-domain analysis software includes AMARES (in jMRUI) and CFIT respectively. Another popular frequency-domain approach is LCModel, which has been successfully used to fit both (1)H and (13)C in vivo NMR spectra. To the best of our knowledge LCModel has not been used to fit (31)P spectra. This study demonstrates the feasibility of using LCModel to quantify in vivo (31)P MR spectra, provided that adequate prior knowledge and LCModel control parameters are used. Both single-voxel and MRSI data are presented, and similar results are obtained with LCModel and with AMARES. This provides a new method for automated, operator-independent analysis of (31)P NMR spectra. PMID:25871439

  10. NMR Constraints Analyser: a web-server for the graphical analysis of NMR experimental constraints.

    PubMed

    Heller, Davide Martin; Giorgetti, Alejandro

    2010-07-01

    Nuclear magnetic resonance (NMR) spectroscopy together with X-ray crystallography, are the main techniques used for the determination of high-resolution 3D structures of biological molecules. The output of an NMR experiment includes a set of lower and upper limits for the distances (constraints) between pairs of atoms. If the number of constraints is high enough, there will be a finite number of possible conformations (models) of the macromolecule satisfying the data. Thus, the more constraints are measured, the better defined these structures will be. The availability of a user-friendly tool able to help in the analysis and interpretation of the number of experimental constraints per residue, is thus of valuable importance when assessing the levels of structure definition of NMR solved biological macromolecules, in particular, when high-quality structures are needed in techniques such as, computational biology approaches, site-directed mutagenesis experiments and/or drug design. Here, we present a free publicly available web-server, i.e. NMR Constraints Analyser, which is aimed at providing an automatic graphical analysis of the NMR experimental constraints atom by atom. The NMR Constraints Analyser server is available from the web-page http://molsim.sci.univr.it/constraint.

  11. Structure calculation, refinement and validation using CcpNmr Analysis

    PubMed Central

    Skinner, Simon P.; Goult, Benjamin T.; Fogh, Rasmus H.; Boucher, Wayne; Stevens, Tim J.; Laue, Ernest D.; Vuister, Geerten W.

    2015-01-01

    CcpNmr Analysis provides a streamlined pipeline for both NMR chemical shift assignment and structure determination of biological macromolecules. In addition, it encompasses tools to analyse the many additional experiments that make NMR such a pivotal technique for research into complex biological questions. This report describes how CcpNmr Analysis can seamlessly link together all of the tasks in the NMR structure-determination process. It details each of the stages from generating NMR restraints [distance, dihedral, hydrogen bonds and residual dipolar couplings (RDCs)], exporting these to and subsequently re-importing them from structure-calculation software (such as the programs CYANA or ARIA) and analysing and validating the results obtained from the structure calculation to, ultimately, the streamlined deposition of the completed assignments and the refined ensemble of structures into the PDBe repository. Until recently, such solution-structure determination by NMR has been quite a laborious task, requiring multiple stages and programs. However, with the new enhancements to CcpNmr Analysis described here, this process is now much more intuitive and efficient and less error-prone. PMID:25615869

  12. NMR data visualization, processing, and analysis on mobile devices.

    PubMed

    Cobas, Carlos; Iglesias, Isaac; Seoane, Felipe

    2015-08-01

    Touch-screen computers are emerging as a popular platform for many applications, including those in chemistry and analytical sciences. In this work, we present our implementation of a new NMR 'app' designed for hand-held and portable touch-controlled devices, such as smartphones and tablets. It features a flexible architecture formed by a powerful NMR processing and analysis kernel and an intuitive user interface that makes full use of the smart devices haptic capabilities. Routine 1D and 2D NMR spectra acquired in most NMR instruments can be processed in a fully unattended way. More advanced experiments such as non-uniform sampled NMR spectra are also supported through a very efficient parallelized Modified Iterative Soft Thresholding algorithm. Specific technical development features as well as the overall feasibility of using NMR software apps will also be discussed. All aspects considered the functionalities of the app allowing it to work as a stand-alone tool or as a 'companion' to more advanced desktop applications such as Mnova NMR. PMID:25924947

  13. NMR data visualization, processing, and analysis on mobile devices.

    PubMed

    Cobas, Carlos; Iglesias, Isaac; Seoane, Felipe

    2015-08-01

    Touch-screen computers are emerging as a popular platform for many applications, including those in chemistry and analytical sciences. In this work, we present our implementation of a new NMR 'app' designed for hand-held and portable touch-controlled devices, such as smartphones and tablets. It features a flexible architecture formed by a powerful NMR processing and analysis kernel and an intuitive user interface that makes full use of the smart devices haptic capabilities. Routine 1D and 2D NMR spectra acquired in most NMR instruments can be processed in a fully unattended way. More advanced experiments such as non-uniform sampled NMR spectra are also supported through a very efficient parallelized Modified Iterative Soft Thresholding algorithm. Specific technical development features as well as the overall feasibility of using NMR software apps will also be discussed. All aspects considered the functionalities of the app allowing it to work as a stand-alone tool or as a 'companion' to more advanced desktop applications such as Mnova NMR.

  14. Deuterium incorporation in biomass cell wall components by NMR analysis

    SciTech Connect

    Foston, Marcus B; McGaughey, Joseph; O'Neill, Hugh Michael; Evans, Barbara R; Ragauskas, Arthur J

    2012-01-01

    A commercially available deuterated kale sample was analyzed for deuterium incorporation by ionic liquid solution 2H and 1H nuclear magnetic resonance (NMR). This protocol was found to effectively measure the percent deuterium incorporation at 33%, comparable to the 31% value determined by combustion. The solution NMR technique also suggested by a qualitative analysis that deuterium is preferentially incorporated into the carbohydrate components of the kale sample.

  15. NMR spectral analysis using prior knowledge

    NASA Astrophysics Data System (ADS)

    Kasai, Takuma; Nagata, Kenji; Okada, Masato; Kigawa, Takanori

    2016-03-01

    Signal assignment is a fundamental step for analyses of protein structure and dynamics with nuclear magnetic resonance (NMR). Main-chain signal assignment is achieved with a sequential assignment method and/or an amino-acid selective stable isotope labeling (AASIL) method. Combinatorial selective labeling (CSL) methods, as well as our labeling strategy, stable isotope encoding (SiCode), were developed to reduce the required number of labeled samples, since one of the drawbacks of AASIL is that many samples are needed. Signal overlapping in NMR spectra interferes with amino-acid determination by CSL and SiCode. Since spectral deconvolution by peak fitting with a gradient method cannot resolve closely overlapped signals, we developed a new method to perform both peak fitting and amino acid determination simultaneously, with a replica exchange Monte Carlo method, incorporating prior knowledge of stable-isotope labeling ratios and the amino-acid sequence of the protein.

  16. Discrete analysis of stochastic NMR.II

    NASA Astrophysics Data System (ADS)

    Wong, S. T. S.; Rods, M. S.; Newmark, R. D.; Budinger, T. F.

    Stochastic NMR is an efficient technique for high-field in vivo imaging and spectroscopic studies where the peak RF power required may be prohibitively high for conventional pulsed NMR techniques. A stochastic NMR experiment excites the spin system with a sequence of RF pulses where the flip angles or the phases of the pulses are samples of a discrete stochastic process. In a previous paper the stochastic experiment was analyzed and analytic expressions for the input-output cross-correlations, average signal power, and signal spectral density were obtained for a general stochastic RF excitation. In this paper specific cases of excitation with random phase, fixed flip angle, and excitation with two random components in quadrature are analyzed. The input-output cross-correlation for these two types of excitations is shown to be Lorentzian. Line broadening is the only spectral distortion as the RF excitation power is increased. The systematic noise power is inversely proportional to the number of data points N used in the spectral reconstruction. The use of a complete maximum length sequence (MLS) may improve the signal-to-systematic-noise ratio by 20 dB relative to random binary excitation, but peculiar features in the higher-order autocorrelations of MLS cause noise-like distortion in the reconstructed spectra when the excitation power is high. The amount of noise-like distortion depends on the choice of the MLS generator.

  17. Development and application of proton NMR methodology to lipoprotein analysis

    NASA Astrophysics Data System (ADS)

    Korhonen, Ari Juhani

    1998-11-01

    The present thesis describes the development of 1H NMR spectroscopy and its applications to lipoprotein analysis in vitro, utilizing biochemical prior knowledge and advanced lineshape fitting analysis in the frequency domain. A method for absolute quantification of lipoprotein lipids and proteins directly from the terminal methyl-CH3 resonance region of 1H NMR spectra of human blood plasma is described. Then the use of NMR methodology in time course studies of the oxidation process of LDL particles is presented. The function of the cholesteryl ester transfer protein (CETP) in lipoprotein mixtures was also assessed by 1H NMR, which allows for dynamic follow-up of the lipid transfer reactions between VLDL, LDL, and HDL particles. The results corroborated the suggestion that neutral lipid mass transfer among lipoproteins is not an equimolar heteroexchange. A novel method for studying lipoprotein particle fusion is also demonstrated. It is shown that the progression of proteolytically (α- chymotrypsin) induced fusion of LDL particles can be followed by 1H NMR spectroscopy and, moreover, that fusion can be distinguished from aggregation. In addition, NMR methodology was used to study the changes in HDL3 particles induced by phospholipid transfer protein (PLTP) in HDL3 + PLTP mixtures. The 1H NMR study revealed a gradual production of enlarged HDL particles, which demonstrated that PLTP-mediated remodeling of HDL involves fusion of the HDL particles. These applications demonstrated that the 1H NMR approach offers several advantages both in quantification and in time course studies of lipoprotein-lipoprotein interactions and of enzyme/lipid transfer protein function.

  18. NMR analysis on microfluidic devices by remote detection

    SciTech Connect

    McDonnell, Erin E.; Han, SongI; Hilty, Christian; Pierce,Kimberly; Pines, Alexander

    2005-08-15

    We present a novel approach to perform high-sensitivity NMR imaging and spectroscopic analysis on microfluidic devices. The application of NMR, the most information rich spectroscopic technique, to microfluidic devices remains a challenge because the inherently low sensitivity of NMR is aggravated by small fluid volumes leading to low NMR signal, and geometric constraints resulting in poor efficiency for inductive detection. We address the latter by physically separating signal detection from encoding of information with remote detection. Thereby, we use a commercial imaging probe with sufficiently large diameter to encompass the entire device, enabling encoding of NMR information at any location on the chip. Because large-diameter coils are too insensitive for detection, we store the encoded information as longitudinal magnetization and flow it into the outlet capillary. There, we detect the signal with optimal sensitivity using a solenoidal microcoil, and reconstruct the information encoded in the fluid. We present a generally applicable design for a detection-only microcoil probe that can be inserted into the bore of a commercial imaging probe. Using hyperpolarized 129Xe gas, we show that this probe enables sensitive reconstruction of NMR spectroscopic information encoded by the large imaging probe while keeping the flexibility of a large coil.

  19. Quantitative analysis of protein-ligand interactions by NMR.

    PubMed

    Furukawa, Ayako; Konuma, Tsuyoshi; Yanaka, Saeko; Sugase, Kenji

    2016-08-01

    Protein-ligand interactions have been commonly studied through static structures of the protein-ligand complex. Recently, however, there has been increasing interest in investigating the dynamics of protein-ligand interactions both for fundamental understanding of the underlying mechanisms and for drug development. NMR is a versatile and powerful tool, especially because it provides site-specific quantitative information. NMR has widely been used to determine the dissociation constant (KD), in particular, for relatively weak interactions. The simplest NMR method is a chemical-shift titration experiment, in which the chemical-shift changes of a protein in response to ligand titration are measured. There are other quantitative NMR methods, but they mostly apply only to interactions in the fast-exchange regime. These methods derive the dissociation constant from population-averaged NMR quantities of the free and bound states of a protein or ligand. In contrast, the recent advent of new relaxation-based experiments, including R2 relaxation dispersion and ZZ-exchange, has enabled us to obtain kinetic information on protein-ligand interactions in the intermediate- and slow-exchange regimes. Based on R2 dispersion or ZZ-exchange, methods that can determine the association rate, kon, dissociation rate, koff, and KD have been developed. In these approaches, R2 dispersion or ZZ-exchange curves are measured for multiple samples with different protein and/or ligand concentration ratios, and the relaxation data are fitted to theoretical kinetic models. It is critical to choose an appropriate kinetic model, such as the two- or three-state exchange model, to derive the correct kinetic information. The R2 dispersion and ZZ-exchange methods are suitable for the analysis of protein-ligand interactions with a micromolar or sub-micromolar dissociation constant but not for very weak interactions, which are typical in very fast exchange. This contrasts with the NMR methods that are used

  20. Computer compensation for NMR quantitative analysis of trace components

    SciTech Connect

    Nakayama, T.; Fujiwara, Y.

    1981-07-22

    A computer program has been written that determines trace components and separates overlapping components in multicomponent NMR spectra. This program uses the Lorentzian curve as a theoretical curve of NMR spectra. The coefficients of the Lorentzian are determined by the method of least squares. Systematic errors such as baseline/phase distortion are compensated and random errors are smoothed by taking moving averages, so that there processes contribute substantially to decreasing the accumulation time of spectral data. The accuracy of quantitative analysis of trace components has been improved by two significant figures. This program was applied to determining the abundance of 13C and the saponification degree of PVA.

  1. NMR-based Structural Analysis of the Complete Rough-type Lipopolysaccharide Isolated from Capnocytophaga canimorsus*

    PubMed Central

    Zähringer, Ulrich; Ittig, Simon; Lindner, Buko; Moll, Hermann; Schombel, Ursula; Gisch, Nicolas; Cornelis, Guy R.

    2014-01-01

    We here describe the NMR analysis of an intact lipopolysaccharide (LPS, endotoxin) in water with 1,2-dihexanoyl-sn-glycero-3-phosphocholine as detergent. When HPLC-purified rough-type LPS of Capnocytophaga canimorsus was prepared, 13C,15N labeling could be avoided. The intact LPS was analyzed by homonuclear (1H) and heteronuclear (1H,13C, and 1H,31P) correlated one- and two-dimensional NMR techniques as well as by mass spectrometry. It consists of a penta-acylated lipid A with an α-linked phosphoethanolamine attached to C-1 of GlcN (I) in the hybrid backbone, lacking the 4′-phosphate. The hydrophilic core oligosaccharide was found to be a complex hexasaccharide with two mannose (Man) and one each of 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo), Gal, GalN, and l-rhamnose residues. Position 4 of Kdo is substituted by phosphoethanolamine, also present in position 6 of the branched ManI residue. This rough-type LPS is exceptional in that all three negative phosphate residues are “masked” by positively charged ethanolamine substituents, leading to an overall zero net charge, which has so far not been observed for any other LPS. In biological assays, the corresponding isolated lipid A was found to be endotoxically almost inactive. By contrast, the intact rough-type LPS described here expressed a 20,000-fold increased endotoxicity, indicating that the core oligosaccharide significantly contributes to the endotoxic potency of the whole rough-type C. canimorsus LPS molecule. Based on these findings, the strict view that lipid A alone represents the toxic center of LPS needs to be reassessed. PMID:24993825

  2. Conformational analysis of small molecules: NMR and quantum mechanics calculations.

    PubMed

    Tormena, Cláudio F

    2016-08-01

    This review deals with conformational analysis in small organic molecules, and describes the stereoelectronic interactions responsible for conformational stability. Conformational analysis is usually performed using NMR spectroscopy through measurement of coupling constants at room or low temperature in different solvents to determine the populations of conformers in solution. Quantum mechanical calculations are used to address the interactions responsible for conformer stability. The conformational analysis of a large number of small molecules is described, using coupling constant measurements in different solvents and at low temperature, as well as recent applications of through-space and through-hydrogen bond coupling constants JFH as tools for the conformational analysis of fluorinated molecules. Besides NMR parameters, stereoelectronic interactions such as conjugative, hyperconjugative, steric and intramolecular hydrogen bond interactions involved in conformational preferences are discussed.

  3. Conformational analysis of small molecules: NMR and quantum mechanics calculations.

    PubMed

    Tormena, Cláudio F

    2016-08-01

    This review deals with conformational analysis in small organic molecules, and describes the stereoelectronic interactions responsible for conformational stability. Conformational analysis is usually performed using NMR spectroscopy through measurement of coupling constants at room or low temperature in different solvents to determine the populations of conformers in solution. Quantum mechanical calculations are used to address the interactions responsible for conformer stability. The conformational analysis of a large number of small molecules is described, using coupling constant measurements in different solvents and at low temperature, as well as recent applications of through-space and through-hydrogen bond coupling constants JFH as tools for the conformational analysis of fluorinated molecules. Besides NMR parameters, stereoelectronic interactions such as conjugative, hyperconjugative, steric and intramolecular hydrogen bond interactions involved in conformational preferences are discussed. PMID:27573182

  4. Fourier Analysis and Structure Determination. Part II: Pulse NMR and NMR Imaging.

    ERIC Educational Resources Information Center

    Chesick, John P.

    1989-01-01

    Uses simple pulse NMR experiments to discuss Fourier transforms. Studies the generation of spin echoes used in the imaging procedure. Shows that pulse NMR experiments give signals that are additions of sinusoids of differing amplitudes, frequencies, and phases. (MVL)

  5. Optimized 31P MRS in the human brain at 7 T with a dedicated RF coil setup

    PubMed Central

    van de Bank, Bart L.; Orzada, Stephan; Smits, Frits; Lagemaat, Miriam W.; Rodgers, Christopher T.; Bitz, Andreas K.

    2015-01-01

    The design and construction of a dedicated RF coil setup for human brain imaging (1H) and spectroscopy (31P) at ultra‐high magnetic field strength (7 T) is presented. The setup is optimized for signal handling at the resonance frequencies for 1H (297.2 MHz) and 31P (120.3 MHz). It consists of an eight‐channel 1H transmit–receive head coil with multi‐transmit capabilities, and an insertable, actively detunable 31P birdcage (transmit–receive and transmit only), which can be combined with a seven‐channel receive‐only 31P array. The setup enables anatomical imaging and 31P studies without removal of the coil or the patient. By separating transmit and receive channels and by optimized addition of array signals with whitened singular value decomposition we can obtain a sevenfold increase in SNR of 31P signals in the occipital lobe of the human brain compared with the birdcage alone. These signals can be further enhanced by 30 ± 9% using the nuclear Overhauser effect by B 1‐shimmed low‐power irradiation of water protons. Together, these features enable acquisition of 31P MRSI at high spatial resolutions (3.0 cm3 voxel) in the occipital lobe of the human brain in clinically acceptable scan times (~15 min). © 2015 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd. PMID:26492089

  6. 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.

  7. Functional group analysis in coal and on coal surfaces by NMR spectroscopy

    SciTech Connect

    Verkade, J.G.

    1990-01-01

    An accurate knowledge of the oxygen-bearing labile hydrogen functional groups (e.g., carboxylic acids, phenols and alcohols) in coal is required for today's increasingly sophisticated coal cleaning and beneficiation processes. Phospholanes (compounds having the general structure -POCH{sub 2}CH{sub 2}O (1)) are being investigated as reagents for the tagging of liable hydrogen functional groups in coal materials with the NMR-active {sup 31}P nucleus. Of twelve such reagents investigated so far, 2 (2-chloro-1,3-dioxaphospholane, ClPOCH{sub 2}CH{sub 2}O) and 8 (2-chloro-1,3-dithiaphospholane, ClPSCH{sub 2}CH{sub 2}S) have been found to be useful in identifying and quantitating, by {sup 31}P NMR spectroscopy, labile hydrogen functional groups in an Illinois No. 6 coal condensate. Reagent 2 has also been used to quantitate moisture in pyridine extracts of Argonne Premium Coal Samples. Preliminary {sup 119}Sn NMR spectroscopic results on model compounds with the new reagent CF{sub 3}C(O)NHSnMe{sub 3} (N-trimethylstannyltrifluoroacetamide, 14) suggest that labile hydrogen functional groups in coal materials may be more precisely identified with 14 than with phospholanes. 14 refs., 2 figs., 2 tabs.

  8. Multinuclear NMR analysis of the antitubercular drug ethionamide

    NASA Astrophysics Data System (ADS)

    Vale, Nuno; Correia, Alexandra; Figueiredo, Patrícia; Santos, Hélder A.

    2016-02-01

    Tuberculosis remains as the deadliest bacterial infection in developing countries, a situation that is particularly aggravated by the increasing spread of multidrug resistant mycobacteria (MDR-TB). In this view, not only new anti-tubercular drugs are urgently needed, but also a better understanding of the existing ones may aid in the future design of more efficient derivatives or surrogates. Ethionamide (ETA) is an anti-tubercular pro-drug used as second-line therapy against MDR-TB, being bio-activated by the mycobacterial monooxygenase EtA. ETA has been the focus of several research works, devoted either to the identification of ETA's metabolites or to the development of novel derivatives potentially useful to fight against tuberculosis. In either case, structural analysis of ETA and related structures is of undeniable relevance, while the presence of sulfur in ETA's structure brings about the possibility of including 33S-NMR in the toolbox of structural analysis techniques. In this work, we have engaged into a multinuclear NMR characterization of ETA, through the study of the drug's solubility in seven deuterated solvents, and of the chemical shifts for different nuclei in ETA. Results showed which are the best conditions to study ETA by NMR and provided some important evidence on the low reactivity of the drug's thioamide group, which may be of relevance for future drug derivatization approaches.

  9. NMR apparatus for in situ analysis of fuel cells

    SciTech Connect

    Gerald, II, Rex E; Rathke, Jerome W

    2012-11-13

    The subject apparatus is a fuel cell toroid cavity detector for in situ analysis of samples through the use of nuclear magnetic resonance. The toroid cavity detector comprises a gas-tight housing forming a toroid cavity where the housing is exposed to an externally applied magnetic field B.sub.0 and contains fuel cell component samples to be analyzed. An NMR spectrometer is electrically coupled and applies a radiofrequency excitation signal pulse to the detector to produce a radiofrequency magnetic field B.sub.1 in the samples and in the toroid cavity. Embedded coils modulate the static external magnetic field to provide a means for spatial selection of the recorded NMR signals.

  10. Erythrocytes in muscular dystrophy. Investigation with /sup 31/P nuclear magnetic resonance spectroscopy

    SciTech Connect

    Sarpel, G.; Lubansky, H.J.; Danon, M.J.; Omachi, A.

    1981-05-01

    Phosphorus 31 nuclear magnetic resonance (/sup 31/P NMR) signals were recorded from intact human erythrocytes for 16 hours. Total phosphate concentration, which was estimated as the sum of the individual /sup 31/P signals, was 25% lower in erythrocytes from men with myotonic dystrophy than in control erythrocytes. The inorganic-phosphate fraction contained the highest average phosphate concentration over the 16-hour period, and made the major contribution to the difference in total phosphate between the two groups. This result was not observed in erythrocytes from either women with myotonic dystrophy or patients with Duchenne's dystrophy and may be due to a change in cell membrane permeability to inorganic phosphate, which leads to lower steady-state concentrations of the intracellular phosphates.

  11. Erythrocytes in muscular dystrophy. Investigation with 31P nuclear magnetic resonance spectroscopy

    SciTech Connect

    Sarpel, G.; Lubansky, H.J.; Danon, M.J.; Omachi, A.

    1981-05-01

    Phosphorus 31 nuclear magnetic resonance (31P NMR) signals were recorded from intact human erythrocytes for 16 hours. Total phosphate concentration, which was estimated as the sum of the individual 31P signals, was 25% lower in erythrocytes from men with myotonic dystrophy than in control erythrocytes. The inorganic-phosphate fraction contained the highest average phosphate concentration over the 16-hour period, and made the major contribution to the difference in total phosphate between the two groups. This result was not observed in erythrocytes from either women with myotonic dystrophy or patients with Duchenne's dystrophy and may be due to a change in cell membrane permeability to inorganic phosphate, which lead to lower steady-state concentrations of the intracellular phosphates.

  12. Homonuclear and Heteronuclear NMR Studies of a Statherin Fragment Bound to Hydroxyapatite Crystals

    SciTech Connect

    Raghunathan, Vinodhkumar; Gibson, James M.; Goobes, Gil; Popham, Jennifer M.; Louie, Elizabeth; Stayton, Patrick; Drobny, Gary P.

    2006-05-11

    Acidic proteins found in mineralized tissues act as nature's crystal engineers, where they play a key role in promoting or inhibiting the growth of minerals such as hydroxyapatite (HAP), Ca10(PO4)6(OH)2, the main mineral component of bone and teeth. Key to understanding the structural basis of protein-crystal recognition and protein control of hard tissue growth is the nature of interactions between the protein side chains and the crystal surface. In an earlier work we have measured the proximity of the lysine (K6) side chain in an SN-15 peptide fragment of the salivary protein statherin adsorbed to the Phosphorus-rich surface of HAP using solid-state NMR recoupling experiments. 15N(31P) rotational echo double resonance (REDOR) NMR data on the side-chain nitrogen in K6 gave rise to three different models of protein-surface interaction to explain the experimental data acquired. In this work we extend the analysis of the REDOR data by examining the contribution of interactions between surface phosphorus atoms to the observed 15N REDOR decay. We performed 31P-31P recoupling experiments in HAP and (NH4)2HPO4 (DHP) to explore the nature of dipolar coupled 31P spin networks. These studies indicate that extensive networks of dipolar coupled 31P spins can be represented as stronger effective dipolar couplings, the existence of which must be included in the analysis of REDOR data. We carried out 15N(31P) REDOR in the case of DHP to determine how the size of the dephasing spin network influences the interpretation of the REDOR data. Although use of an extended 31P coupled spin network simulates the REDOR data well, a simplified 31P dephasing system composed of two spins with a larger dipolar coupling also simulates the REDOR data and only perturbs the heteronuclear couplings very slightly. The 31P-31P dipolar couplings between phosphorus nuclei in HAP can be replaced by an effective dipolar interaction of 600 Hz between two 31P spins. We incorporated this coupling and

  13. Multivariate analysis relating oil shale geochemical properties to NMR relaxometry

    USGS Publications Warehouse

    Birdwell, Justin E.; Washburn, Kathryn E.

    2015-01-01

    Low-field nuclear magnetic resonance (NMR) relaxometry has been used to provide insight into shale composition by separating relaxation responses from the various hydrogen-bearing phases present in shales in a noninvasive way. Previous low-field NMR work using solid-echo methods provided qualitative information on organic constituents associated with raw and pyrolyzed oil shale samples, but uncertainty in the interpretation of longitudinal-transverse (T1–T2) relaxometry correlation results indicated further study was required. Qualitative confirmation of peaks attributed to kerogen in oil shale was achieved by comparing T1–T2 correlation measurements made on oil shale samples to measurements made on kerogen isolated from those shales. Quantitative relationships between T1–T2 correlation data and organic geochemical properties of raw and pyrolyzed oil shales were determined using partial least-squares regression (PLSR). Relaxometry results were also compared to infrared spectra, and the results not only provided further confidence in the organic matter peak interpretations but also confirmed attribution of T1–T2 peaks to clay hydroxyls. In addition, PLSR analysis was applied to correlate relaxometry data to trace element concentrations with good success. The results of this work show that NMR relaxometry measurements using the solid-echo approach produce T1–T2 peak distributions that correlate well with geochemical properties of raw and pyrolyzed oil shales.

  14. In vivo 31P nuclear magnetic resonance investigation of tellurite toxicity in Escherichia coli.

    PubMed

    Lohmeier-Vogel, Elke M; Ung, Shiela; Turner, Raymond J

    2004-12-01

    Here we compare the physiological state of Escherichia coli exposed to tellurite or selenite by using the noninvasive technique of phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy. We studied glucose-fed Escherichia coli HB101 cells containing either a normal pUC8 plasmid with no tellurite resistance determinants present or the pTWT100 plasmid which contains the resistance determinants tehAB. No differences could be observed in intracellular ATP levels, the presence or absence of a transmembrane pH gradient, or the levels of phosphorylated glycolytic intermediates when resistant cells were studied by 31P NMR in the presence or absence of tellurite. In the sensitive strain, we observed that the transmembrane pH gradient was dissipated and intracellular ATP levels were rapidly depleted upon exposure to tellurite. Only the level of phosphorylated glycolytic intermediates remained the same as observed with resistant cells. Upon exposure to selenite, no differences could be observed by 31P NMR between resistant and sensitive strains, suggesting that the routes for selenite and tellurite reduction within the cells differ significantly, since only tellurite is able to collapse the transmembrane pH gradient and lower ATP levels in sensitive cells. The presence of the resistance determinant tehAB, by an as yet unidentified detoxification event, protects the cells from uncoupling by tellurite.

  15. In Vivo 31P Nuclear Magnetic Resonance Investigation of Tellurite Toxicity in Escherichia coli

    PubMed Central

    Lohmeier-Vogel, Elke M.; Ung, Shiela; Turner, Raymond J.

    2004-01-01

    Here we compare the physiological state of Escherichia coli exposed to tellurite or selenite by using the noninvasive technique of phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy. We studied glucose-fed Escherichia coli HB101 cells containing either a normal pUC8 plasmid with no tellurite resistance determinants present or the pTWT100 plasmid which contains the resistance determinants tehAB. No differences could be observed in intracellular ATP levels, the presence or absence of a transmembrane pH gradient, or the levels of phosphorylated glycolytic intermediates when resistant cells were studied by 31P NMR in the presence or absence of tellurite. In the sensitive strain, we observed that the transmembrane pH gradient was dissipated and intracellular ATP levels were rapidly depleted upon exposure to tellurite. Only the level of phosphorylated glycolytic intermediates remained the same as observed with resistant cells. Upon exposure to selenite, no differences could be observed by 31P NMR between resistant and sensitive strains, suggesting that the routes for selenite and tellurite reduction within the cells differ significantly, since only tellurite is able to collapse the transmembrane pH gradient and lower ATP levels in sensitive cells. The presence of the resistance determinant tehAB, by an as yet unidentified detoxification event, protects the cells from uncoupling by tellurite. PMID:15574934

  16. Bloch-Siegert B1+-Mapping for Human Cardiac 31P-MRS at 7 Tesla

    PubMed Central

    Clarke, William T.; Robson, Matthew D.; Rodgers, Christopher T.

    2016-01-01

    Purpose Phosphorus MR spectroscopy (31P-MRS) is a powerful tool for investigating tissue energetics in vivo. Cardiac 31P-MRS is typically performed using surface coils that create an inhomogeneous excitation field across the myocardium. Accurate measurements of B1+ (and hence flip angle) are necessary for quantitative analysis of 31P-MR spectra. We demonstrate a Bloch-Siegert B1+-mapping method for this purpose. Theory and Methods We compare acquisition strategies for Bloch-Siegert B1+-mapping when there are several spectral peaks. We optimize a Bloch-Siegert sensitizing (Fermi) pulse for cardiac 31P-MRS at 7 Tesla (T) and apply it in a three-dimensional (3D) chemical shift imaging sequence. We validate this in phantoms and skeletal muscle (against a dual-TR method) and present the first cardiac 31P B1+-maps at 7T. Results The Bloch-Siegert method correlates strongly (Pearson’s r = 0.90 and 0.84) and has bias <25 Hz compared with a multi-TR method in phantoms and dual-TR method in muscle. Cardiac 3D B1+-maps were measured in five normal volunteers. B1+ maps based on phosphocreatine and alpha-adenosine-triphosphate correlated strongly (r = 0.62), confirming that the method is T1 insensitive. Conclusion The 3D 31P Bloch-Siegert B1+-mapping is consistent with reference methods in phantoms and skeletal muscle. It is the first method appropriate for 31P B1+-mapping in the human heart at 7T. PMID:26509652

  17. A new laboratory approach to shale analysis using NMR relaxometry

    USGS Publications Warehouse

    Washburn, Kathryn E.; Birdwell, Justin E.; Baez, Luis; Beeney, Ken; Sonnenberg, Steve

    2013-01-01

    kerogen, thermally degraded kerogen, and char. Integrated peak areas from the LF-NMR results representative of kerogen and bitumen were found to be well correlated with S1 and S2 parameters from Rock-Eval programmed pyrolysis. This study demonstrates that LFNMR relaxometry can provide a wide range of information on shales and other reservoir rocks that goes well beyond porosity and pore-fluid analysis.

  18. Off-resonance rotating frame spin-lattice NMR relaxation studies of phosphorus metabolite rotational diffusion in bovine lens homogenates

    SciTech Connect

    Caines, G.H.; Schleich, T.; Morgan, C.F. ); Farnsworth, P.N. )

    1990-08-21

    The rotational diffusion behavior of phosphorus metabolites present in calf lens cortical and nuclear homogenates was investigated by the NMR technique of {sup 31}P off-resonance rotating frame spin-lattice relaxation as a means of assessing the occurrence and extent of phosphorus metabolite-lens protein interactions. {sup 31}P NMR spectra of calf lens homogenates were obtained at 10 and 18{degree}C at 7.05 T. Effective rotational correlation times ({tau}{sub 0,eff}) for the major phosphorus metabolites present in cortical and nuclear bovine calf lens homogenates were derived from nonlinear least-squares analysis of R vs {omega}{sub e} data with the assumption of isotropic reorientational motion. Intramolecular dipole-dipole ({sup 1}H-{sup 31}P, {sup 31}P-{sup 31}P), chemical shift anisotropy (CSA), and solvent (water) translational intermolecular dipole-dipole ({sup 1}H-{sup 31}P) relaxation contributions were assumed in the analyses. A fast-exchange model between free and bound forms, was employed in the analysis of the metabolite R vs {omega}{sub e} curves to yield the fraction of free (unbound) metabolite ({Theta}{sub free}). The results of this study establish the occurrence of significant temperature-dependent (above and below the cold cataract phase transition temperature) binding of ATP (cortex) and PME (nucleus) and p{sub i} (nucleus) in calf lens.

  19. Gated in vivo examination of cardiac metabolites with /sup 31/P nuclear magnetic resonance

    SciTech Connect

    Kantor, H.L.; Briggs, R.W.; Metz, K.R.; Balaban, R.S.

    1986-07-01

    Phosphorus-31 nuclear magnetic resonance (/sup 31/P NMR) spectroscopy was used to study the temporal aspects of metabolism of canine heart in vivo. An NMR catheter coil was passed through the jugular vein of a dog into the apex of the right ventricle and spectra were recorded at four points in the cardiac cycle by triggering from the blood pressure trace of the animal. The /sup 31/P spin-lattice relaxation times of phosphocreatine (PC) and the ..gamma../sup -/,..cap alpha../sup -/, and ..beta..-phosphates of ATP at 1.89 Tesla are 4.4, 1.8, 1.7, and 1.6 s, respectively. The ratio of PC to ATP is 2.0. No changes in PC/ATP were noted in any of the four portions of the cardiac cycle examined, and difference spectra exhibited no observable signals, in contrast to previously reported results for glucose-perfused rat hearts. On the assumption that intracellular pH and the total creatine pool were constant, the expression for the creatine kinase reaction was used to deduce that free ADP concentrations were invariant throughout the cardiac cycle. This is in apparent disagreement with the proposed regulatory role for ADP in heart oxidative phosphorylation.

  20. Analysis of bacterial biofilms using NMR-based metabolomics

    PubMed Central

    Zhang, Bo; Powers, Robert

    2013-01-01

    Infectious diseases can be difficult to cure, especially if the pathogen forms a biofilm. After decades of extensive research into the morphology, physiology and genomics of biofilm formation, attention has recently been directed toward the analysis of the cellular metabolome in order to understand the transformation of a planktonic cell to a biofilm. Metabolomics can play an invaluable role in enhancing our understanding of the underlying biological processes related to the structure, formation and antibiotic resistance of biofilms. A systematic view of metabolic pathways or processes responsible for regulating this ‘social structure’ of microorganisms may provide critical insights into biofilm-related drug resistance and lead to novel treatments. This review will discuss the development of NMR-based metabolomics as a technology to study medically relevant biofilms. Recent advancements from case studies reviewed in this manuscript have shown the potential of metabolomics to shed light on numerous biological problems related to biofilms. PMID:22800371

  1. Review of NMR characterization of pyrolysis oils

    DOE PAGES

    Hao, Naijia; Ben, Haoxi; Yoo, Chang Geun; Adhikari, Sushil; Ragauskas, Arthur J.

    2016-08-24

    Here, pyrolysis of renewable biomass has been developed as a method to produce green fuels and chemicals in response to energy security concerns as well as to alleviate environmental issues incurred with fossil fuel usage. However, pyrolysis oils still have limited commercial application, mainly because unprocessed oils cannot be readily blended with current petroleum-based transportation fuels. To better understand these challenges, researchers have applied diverse characterization techniques in the development of bio-oil studies. In particular, nuclear magnetic resonance (NMR) is a key spectroscopic characterization method through analysis of bio-oil components. This review highlights the NMR strategies for pyrolysis oil characterizationmore » and critically discusses the applications of 1H, 13C, 31P, 19F, and two-dimensional (2-D NMR) analyses such as heteronuclear single quantum correlation (HSQC) in representative pyrolysis oil studies.« less

  2. A theoretical study of rotational diffusion models for rod-shaped viruses. The influence of motion on 31P nuclear magnetic resonance lineshapes and transversal relaxation.

    PubMed Central

    Magusin, P C; Hemminga, M A

    1993-01-01

    Information about the interaction between nucleic acids and coat proteins in intact virus particles may be obtained by studying the restricted backbone dynamics of the incapsulated nucleic acids using 31P nuclear magnetic resonance (NMR) spectroscopy. In this article, simulations are carried out to investigate how reorientation of a rod-shaped virus particle as a whole and isolated nucleic acid motions within the virion influence the 31P NMR lineshape and transversal relaxation dominated by the phosphorus chemical shift anisotropy. Two opposite cases are considered on a theoretical level. First, isotropic rotational diffusion is used as a model for mobile nucleic acids that are loosely or partially bound to the protein coat. The effect of this type of diffusion on lineshape and transversal relaxation is calculated by solving the stochastic Liouville equation by an expansion in spherical functions. Next, uniaxial rotational diffusion is assumed to represent the mobility of phosphorus in a virion that rotates as a rigid rod about its length axis. This type of diffusion is approximated by an exchange process among discrete sites. As turns out from these simulations, the amplitude and the frequency of the motion can only be unequivocally determined from experimental data by a combined analysis of the lineshape and the transversal relaxation. In the fast motional region both the isotropic and the uniaxial diffusion model predict the same transversal relaxation as the Redfield theory. For very slow motion, transversal relaxation resembles the nonexponential relaxation as observed for water molecules undergoing translational diffusion in a magnetic field gradient. In this frequency region T2e is inversely proportional to the cube root of the diffusion coefficient. In addition to the isotropic and uniaxial diffusion models, a third model is presented, in which fast restricted nucleic acid backbone motions dominating the lineshape are superimposed on a slow rotation of the

  3. Chemical analysis using J-coupling multiplets in zero-field NMR

    NASA Astrophysics Data System (ADS)

    Theis, Thomas; Blanchard, John W.; Butler, Mark C.; Ledbetter, Micah P.; Budker, Dmitry; Pines, Alexander

    2013-08-01

    Zero-field nuclear magnetic resonance (NMR) spectroscopy is emerging as a new, potentially portable, and cost-effective NMR modality with the ability to provide information-rich, high-resolution spectra. We present simple rules for analysis of zero-field NMR spectra based on first-order perturbation theory and the addition of angular momenta. These rules allow for the prediction of observed spectral lines without numerical simulation. Results are presented for a few small organic molecules with characteristic spin topologies, demonstrating unambiguous assignment of peaks, highlighting the potential of zero-field NMR as a tool for chemical identification.

  4. Magic-angle-spinning NMR on solid biological systems. Analysis Of the origin of the spectral linewidths

    NASA Astrophysics Data System (ADS)

    Hemminga, M. A.; de Jager, P. A.; Krüse, J.; Lamerichs, R. M. J. N.

    Magic-angle-spinning (MAS) high-power 1H-decoupled 13C and 31P NMR has been applied to solid biological materials to obtain information about the mechanisms that determine the spectral linewidths. The line broadening in MAS 31P NMR spectra of solid tobacco mosaic virus (TMV) has been investigated by selective saturation and T2 measurements. About 90 Hz stems from homogeneous effects, whereas the inhomogeneous contribution is approximately 100 Hz. The inhomogeneous line broadening is assigned to macroscopic inhomogeneities in the sample and not to variations in the nucleotide bases along the RNA strand in TMV. It is concluded that sample preparation is of vital importance for obtaining well-resolved spectra. Under optimal preparation techniques the isotropic values of the chemical shift of the different 31P sites have been determined to obtain information about the secondary structure of the viral RNA. The chemical shift anisotropy has been determined from the relative intensities of the spinning side bands in the spectra. The chemical shift information is used to make a tentative assignment of the resonance in terms of the three structurally distinguishable phosphate groups in TMV. The origin of the linewidths in MAS NMR has been examined further by 13C NMR of approximately 10% 13C-enriched coat protein of cowpea chlorotic mottle virus, using selective excitation and saturation techniques, as well as measurements of the relaxation times T1 γ and T2. The CO resonance in the spectrum is composed of an inhomogeneous and homogeneous part with a total linewidth of 700 Hz. The homogeneous linewidth, contributing with 200 Hz, is found to arise from slow molecular motions in the solid on a millisecond timescale.

  5. Experimental estimation of postmortem interval using multivariate analysis of proton NMR metabolomic data.

    PubMed

    Hirakawa, Keiko; Koike, Kaoru; Uekusa, Kyoko; Nihira, Makoto; Yuta, Kohtaro; Ohno, Youkichi

    2009-04-01

    Nuclear magnetic resonance (NMR) spectroscopy has recently been applied to metabolic studies. In particular, metabolic profiles of tissues or of the whole body can easily be acquired through multivariate analysis of NMR spectra. The present study investigates metabolic changes after death in rat femoral muscles using pattern recognition of proton NMR spectra. Rats were killed by suffocation, cocaine overdose and induced respiratory failure, and then low molecular weight metabolites extracted using perchlorate from excised tissues were measured using proton NMR. All spectral data were processed and assessed by multivariate analysis to obtain metabolic profiles of the tissues. The results of principal component analysis (PCA) score plots soon after death showed that the metabolic profiles of the tissues differed according to the mode of death. The principal component (PC) scores of the data varied hourly and correlated with postmortem interval. The present results showed that NMR-based metabolic profiling could provide useful information with which to estimate postmortem intervals and causes of death.

  6. An Analysis of a Commercial Furniture Refinisher: A Comprehensive Introductory NMR Experiment.

    ERIC Educational Resources Information Center

    Markow, Peter G.; Cramer, John A.

    1983-01-01

    Describes a comprehensive nuclear magnetic resonance (NMR) experiment designed to introduce undergraduate organic chemistry students to measurement/interpretation of NMR parameters. Students investigate chemical shift analysis, spin-spin coupling, peak integrations, effect of deuterium oxide extraction, and comparisons with literature spectra;…

  7. Novel approach to the detection and quantification of phenolic compounds in olive oil based on 31P nuclear magnetic resonance spectroscopy.

    PubMed

    Christophoridou, Stella; Dais, Photis

    2006-02-01

    31P NMR spectroscopy has been employed to detect and quantify phenolic compounds in the polar fraction of virgin olive oil. This novel analytical method is based on the derivatization of the hydroxyl and carboxyl groups of phenolic compounds with 2-chloro-4,4,5,5-tetramethyldioxaphospholane and the identification of the phosphitylated compounds on the basis of the 31P chemical shifts. Quantification of a large number of phenolic compounds in virgin olive oil can be accomplished by integration of the appropriate signals in the 31P NMR spectrum and the use of the phosphitylated cyclohexanol as internal standard. Finally, the validity of this technique for quantitative measurements was thoroughly examined. PMID:16448164

  8. Double cross polarization /sup 13/C-NMR experiment in solid fossil fuel structure analysis

    SciTech Connect

    Hagaman, E.W.; Woody, M.C.

    1988-01-01

    The Double Cross Polarization /sup 13/C-MAS/NMR experiment has been used to derive a new operational classification of solid fossil fuels based on chemical reactivity. The method requires labeling reactive sites in the organic matrix with a magnetically active isotope not present in the precursor material, and using the local, isolated dipole-dipole interaction between this nucleus and nearby /sup 13/C nuclei to detect via cross polarization the carbon centers in the vicinity of the label. The technique is a marriage of chemistry and spectroscopy and the information content of the DCP spectra is defined by both partners. /sup 1/H-/sup 13/C-/sup 31/P DCP/MAS /sup 13/C-NMR spectroscopy has been used to statistically describe phenolic ortho-substitution patterns of coals via their aryl phosphinate or phosphate derivatives. In these applications of DCP NMR the new, detailed structure and/or reactivity information is realized by detection of carbon resonances one or more bonds removed from the reaction center, but in a volume element of intramolecular dimensions. To the extent that intermolecular contributions to the spectrum are detected, and not recognized as such, the structure/reactivity correlation is weakened. Direct substitution of phosphorus on the aromatic rings in the organic matrix of the coal is not readily accomplished. This environment potentially can be labeled with fluorine in a selective fashion using newly developed reagents. The possibility of determining the changes in average ring substitution patterns as a function of chemical treatment or coal diagenesis emerges. Recent developments in the field of DCP /sup 13/C NMR are presented.

  9. NMR analysis of a stress response metabolic signaling network.

    PubMed

    Zhang, Bo; Halouska, Steven; Schiaffo, Charles E; Sadykov, Marat R; Somerville, Greg A; Powers, Robert

    2011-08-01

    We previously hypothesized that Staphylococcus epidermidis senses a diverse set of environmental and nutritional factors associated with biofilm formation through a modulation in the activity of the tricarboxylic acid (TCA) cycle. Herein, we report our further investigation of the impact of additional environmental stress factors on TCA cycle activity and provide a detailed description of our NMR methodology. S. epidermidis wild-type strain 1457 was treated with stressors that are associated with biofilm formation, a sublethal dose of tetracycline, 5% NaCl, 2% glucose, and autoinducer-2 (AI-2). As controls and to integrate our current data with our previous study, 4% ethanol stress and iron-limitation were also used. Consistent with our prior observations, the effect of many environmental stress factors on the S. epidermidis metabolome was essentially identical to the effect of TCA cycle inactivation in the aconitase mutant strain 1457-acnA::tetM. A detailed quantitative analysis of metabolite concentration changes using 2D (1)H-(13)C HSQC and (1)H-(1)H TOCSY spectra identified a network of 37 metabolites uniformly affected by the stressors and TCA cycle inactivation. We postulate that the TCA cycle acts as the central pathway in a metabolic signaling network.

  10. Structural analysis of sulfated fucans by high-field NMR.

    PubMed

    Mulloy, B; Ribeiro, A C; Vieira, R P; Mourão, P A

    1994-02-01

    The structures of several sulfated polysaccharides isolated from marine organisms have been determined by a combination of degradative and spectroscopic techniques. For two sulphated fucans, one isolated from the sea cucumber L. grisea, and one from the sea urchin L. variegatus, a novel type of polysaccharide structure is proposed based on the analysis of one- and two-dimensional nuclear magnetic resonance (NMR) spectra. Both polysaccharides are linear, 1-->3 linked alpha-L-fucans in which a four-residue repeating unit is defined by specific patterns of sulfation at the 2- and 4-positions. The four residues give rise to spin systems which may be identified by 2-dimensional 1H-1H correlated spectroscopy (COSY), and the sequence of the residues is deduced from inter-residue nuclear Overhauser enhancements which produce cross-peaks in the NOESY spectrum. To the best of our knowledge, these are the first polysaccharides for which a regular repeating unit is defined by the pattern of sulfate substitution alone.

  11. Initiation sites of protein folding by NMR analysis.

    PubMed Central

    Freund, S M; Wong, K B; Fersht, A R

    1996-01-01

    Detailed characterization of denatured states of proteins is necessary to understand the interactions that funnel the large number of possible conformations along fast routes for folding. Nuclear magnetic resonance experiments based on the nuclear Overhauser effect (NOE) detect hydrogen atoms close in space and provide information about local structure. Here we present an NMR procedure that detects almost all sequential NOEs between amide hydrogen atoms (HN-HN NOE), including those in random coil regions in a protein, barnase, in urea solutions. A semi-quantitative analysis of these HN-HN NOEs identified partly structured regions that are in remarkable agreement with those found to form early on the reaction pathway. Our results strongly suggest that the folding of barnase initiates at the first helix and the beta-turn between the third and the fourth strands. This strategy of defining residual structure has also worked for cold-denatured barstar and guanidinium hydrochloride-denatured chymotrypsin inhibitor 2 and so should be generally applicable. Images Fig. 1 Fig. 3 PMID:8855224

  12. NMR analysis of a stress response metabolic signaling network.

    PubMed

    Zhang, Bo; Halouska, Steven; Schiaffo, Charles E; Sadykov, Marat R; Somerville, Greg A; Powers, Robert

    2011-08-01

    We previously hypothesized that Staphylococcus epidermidis senses a diverse set of environmental and nutritional factors associated with biofilm formation through a modulation in the activity of the tricarboxylic acid (TCA) cycle. Herein, we report our further investigation of the impact of additional environmental stress factors on TCA cycle activity and provide a detailed description of our NMR methodology. S. epidermidis wild-type strain 1457 was treated with stressors that are associated with biofilm formation, a sublethal dose of tetracycline, 5% NaCl, 2% glucose, and autoinducer-2 (AI-2). As controls and to integrate our current data with our previous study, 4% ethanol stress and iron-limitation were also used. Consistent with our prior observations, the effect of many environmental stress factors on the S. epidermidis metabolome was essentially identical to the effect of TCA cycle inactivation in the aconitase mutant strain 1457-acnA::tetM. A detailed quantitative analysis of metabolite concentration changes using 2D (1)H-(13)C HSQC and (1)H-(1)H TOCSY spectra identified a network of 37 metabolites uniformly affected by the stressors and TCA cycle inactivation. We postulate that the TCA cycle acts as the central pathway in a metabolic signaling network. PMID:21692534

  13. NMR of a Phospholipid: Modules for Advanced Laboratory Courses

    NASA Astrophysics Data System (ADS)

    Gaede, Holly C.; Stark, Ruth E.

    2001-09-01

    A laboratory project is described that builds upon the NMR experience undergraduates receive in organic chemistry with a battery of NMR experiments that investigate egg phosphatidylcholine (egg PC). This material, often labeled in health food stores as lecithin, is a major constituent of mammalian cell membranes. The NMR experiments may be used to make resonance assignments, to study molecular organization in model membranes, to test the effects of instrumental parameters, and to investigate the physics of nuclear spin systems. A suite of modular NMR exercises is described, so that the instructor may tailor the laboratory sessions to biochemistry, instrumental analysis, or physical chemistry. The experiments include solution-state one-dimensional (1D) 1H, 13C, and 31P experiments; two-dimensional (2D) TOtal Correlated SpectroscopY (TOCSY); and the spectral editing technique of Distortionless Enhancement by Polarization Transfer (DEPT). To demonstrate the differences between solution and solid-state NMR spectroscopy and instrumentation, a second set of experiments generates 1H, 13C, and 31P spectra of egg PC dispersed in aqueous solution, under both static and magic-angle spinning conditions.

  14. Total lineshape analysis of high-resolution NMR spectra powered by simulated annealing

    NASA Astrophysics Data System (ADS)

    Cheshkov, D. A.; Sinitsyn, D. O.; Sheberstov, K. F.; Chertkov, V. A.

    2016-11-01

    The novel algorithm for a total lineshape analysis of high-resolution NMR spectra has been developed. A global optimization by simulated annealing has been applied that has allowed to overcome the main trouble of common approaches which had frequently returned solutions for local minima rather than for global ones. The algorithm has been verified for the four-spin test systems ABCD, and has been successfully used for analysis of experimental NMR spectra of proline. The approach has allowed to avoid a sophisticated manual setup of initial parameters and to conduct the analysis of complicated high-resolution NMR spectra nearly automatically.

  15. 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.

  16. Carbohydrate utilization by the ischemic perfused heart: an NMR analysis

    SciTech Connect

    Brainard, J.R.; Hutson, J.Y.; Hoekenga, D.E.; Lenhoff, R.J.

    1987-05-01

    During ischemia, carbohydrate is necessarily the primary fuel for generation of energy by anaerobic glycolysis. The relative contributions of glycogen and exogenous glucose to glycolysis in the ischemic guinea pig heart were determined by /sup 13/C labeling and NMR. Glycogen was labeled by preischemic perfusion with (1-/sup 13/C)glucose. (2-/sup 13/C)glucose was then supplied in fresh perfusate during 17 minutes of ischemia. Insulin was included in each case. The relative contribution of glycogen and glucose to glycolysis was determined from /sup 13/C spectra obtained during ischemia and by analysis of /sup 1/H spectra of lactate isolated from hearts freeze-clamped at the end of ischemia. The relative amounts of (2-/sup 13/C)lactate, (3-/sup 13/C)lactate, and natural abundance lactate produced during ischemia correspond to contributions to glycolysis by (2-/sup 13/C)glucose, (1-/sup 13/C)glycogen, and natural abundance glycogen, respectively. Glucose utilization during 17 minutes of ischemia, determined from integration of labeled lactate peaks from /sup 13/C spectra, increased from 11 to 35% of the labeled carbohydrate utilization when perfusate glucose increased from 3 to 11.7 mM. Analysis of labeled lactate formation as a function of time during ischemia suggests that glucose is preferentially utilized early during the ischemic period. They conclude that glucose can contribute significantly as a fuel source in the ischemic heart; the extent depends on the concentration of glucose available to the heart and on the duration of ischemia.

  17. Characterizing dissolved and particulate phosphorus in water with 31P nuclear magnetic resonance spectroscopy.

    PubMed

    Cade-Menun, Barbara J; Navaratnam, John A; Walbridge, Mark R

    2006-12-15

    Management of aquatic ecosystems is hampered because current methodology limits characterization of phosphorus (P)forms. We developed a procedure to characterize dissolved (DP) and particulate (PP) P from river waters by solution 31P nuclear magnetic resonance (NMR) spectroscopy, using 4-L samples, and tested this procedure with a spiking trial. Most P was orthophosphate. Organic P forms included phosphonates, myo-inositol hexakisphosphate, and orthophosphate diesters. This research represents an important technical advance to characterize DP and PP in natural waters. It is simple, uses samples small enough for routine collection, and puts PP and DP into the same chemical environment for direct comparison. The technique is sensitive, detecting changes in spectra from P additions as small as 2% of total P, and identifying differences from two points along the flow path of a single river. However, lyophilizing samples in NaOH-ethylenediamine-tetraacetic acid (EDTA) may alter some P forms, which requires further investigation.

  18. Structural analysis of molybdo-zinc-phosphate glasses: Neutron scattering, FTIR, Raman scattering, MAS NMR studies

    NASA Astrophysics Data System (ADS)

    Renuka, C.; Shinde, A. B.; Krishna, P. S. R.; Reddy, C. Narayana

    2016-08-01

    Vitreous samples were prepared in the xMoO3-17ZnO-(83-x) NaPO3 with 35 ≥ x ≥ 55 glass forming system by energy efficient microwave heating method. Structural evolution of the vitreous network was monitored as a function of composition by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), Raman scattering, Magic Angle Spin Nuclear magnetic resonance (MAS NMR) and Neutron scattering. Addition of MoO3 to the ZnO-NaPO3 glass leads to a pronounced increase in glass transition temperature (Tg) suggesting a significant increase in network connectivity and strength. In order to analyze FTIR and Raman scattering, a simple structural model is presented to rationalize the experimental observations. A number of structural units are formed due to network modification, and the resulting glass may be characterized by a network polyhedral with different numbers of unshared corners. 31P MAS NMR confirms a clear distinction between structural species having 3, 2, 1, 0 bridging oxygens (BOs). Further, Neutron scattering studies were used to probe the structure of these glasses. The result suggests that all the investigated glasses have structures based on chains of four coordinated phosphate and six coordinated molybdate units, besides, two different lengths of P-O bonds in tetrahedral phosphate units that are assigned to bonds of the P-atom with terminal and bridging oxygen atoms.

  19. NMR-based analysis of the chemical composition of Japanese persimmon aqueous extracts.

    PubMed

    Ryu, Shoraku; Furihata, Kazuo; Koda, Masanori; Wei, Feifei; Miyakawa, Takuya; Tanokura, Masaru

    2016-03-01

    Japanese persimmon (Diospyros kaki L.) is recognized as an outstanding source of biologically active compounds relating to many health benefits. In the present study, NMR spectroscopy provided a comprehensive metabolic overview of Japanese persimmon juice. Detailed signal assignments of Japanese persimmon juice were carried out using various 2D NMR techniques incorporated with broadband water suppression enhanced through T1 effects (BB-WET) or WET sequences, and 26 components, including minor components, were identified. In addition, most components were quantitatively evaluated by the integration of signals using conventional (1) H NMR and BB-WET NMR. This is the first detailed analysis combined with quantitative characterization of chemical components using NMR for Japanese persimmon. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26482562

  20. NMR-based analysis of the chemical composition of Japanese persimmon aqueous extracts.

    PubMed

    Ryu, Shoraku; Furihata, Kazuo; Koda, Masanori; Wei, Feifei; Miyakawa, Takuya; Tanokura, Masaru

    2016-03-01

    Japanese persimmon (Diospyros kaki L.) is recognized as an outstanding source of biologically active compounds relating to many health benefits. In the present study, NMR spectroscopy provided a comprehensive metabolic overview of Japanese persimmon juice. Detailed signal assignments of Japanese persimmon juice were carried out using various 2D NMR techniques incorporated with broadband water suppression enhanced through T1 effects (BB-WET) or WET sequences, and 26 components, including minor components, were identified. In addition, most components were quantitatively evaluated by the integration of signals using conventional (1) H NMR and BB-WET NMR. This is the first detailed analysis combined with quantitative characterization of chemical components using NMR for Japanese persimmon. Copyright © 2015 John Wiley & Sons, Ltd.

  1. NMR/MS Translator for the Enhanced Simultaneous Analysis of Metabolomics Mixtures by NMR Spectroscopy and Mass Spectrometry: Application to Human Urine.

    PubMed

    Bingol, Kerem; Brüschweiler, Rafael

    2015-06-01

    A novel metabolite identification strategy is presented for the combined NMR/MS analysis of complex metabolite mixtures. The approach first identifies metabolite candidates from 1D or 2D NMR spectra by NMR database query, which is followed by the determination of the masses (m/z) of their possible ions, adducts, fragments, and characteristic isotope distributions. The expected m/z ratios are then compared with the MS(1) spectrum for the direct assignment of those signals of the mass spectrum that contain information about the same metabolites as the NMR spectra. In this way, the mass spectrum can be assigned with very high confidence, and it provides at the same time validation of the NMR-derived metabolites. The method was first demonstrated on a model mixture, and it was then applied to human urine collected from a pool of healthy individuals. A number of metabolites could be detected that had not been reported previously, further extending the list of known urine metabolites. The new analysis approach, which is termed NMR/MS Translator, is fully automated and takes only a few seconds on a computer workstation. NMR/MS Translator synergistically uses the power of NMR and MS, enhancing the accuracy and efficiency of the identification of those metabolites compiled in databases. PMID:25881480

  2. Computer systems for laboratory networks and high-performance NMR.

    PubMed

    Levy, G C; Begemann, J H

    1985-08-01

    Modern computer technology is significantly enhancing the associated tasks of spectroscopic data acquisition and data reduction and analysis. Distributed data processing techniques, particularly laboratory computer networking, are rapidly changing the scientist's ability to optimize results from complex experiments. Optimization of nuclear magnetic resonance spectroscopy (NMR) and magnetic resonance imaging (MRI) experimental results requires use of powerful, large-memory (virtual memory preferred) computers with integrated (and supported) high-speed links to magnetic resonance instrumentation. Laboratory architectures with larger computers, in order to extend data reduction capabilities, have facilitated the transition to NMR laboratory computer networking. Examples of a polymer microstructure analysis and in vivo 31P metabolic analysis are given. This paper also discusses laboratory data processing trends anticipated over the next 5-10 years. Full networking of NMR laboratories is just now becoming a reality. PMID:3840171

  3. In situ NMR analysis of fluids contained in sedimentary rock

    PubMed

    de Swiet TM; Tomaselli; Hurlimann; Pines

    1998-08-01

    Limitations of resolution and absorption in standard chemical spectroscopic techniques have made it difficult to study fluids in sedimentary rocks. In this paper, we show that a chemical characterization of pore fluids may be obtained in situ by magic angle spinning (MAS) nuclear magnetic resonance (NMR), which is normally used for solid samples. 1H MAS-NMR spectra of water and crude oil in Berea sandstone show sufficient chemical shift resolution for a straightforward determination of the oil/water ratio. Copyright 1998 Academic Press.

  4. NMR Tube Degradation Method for Sugar Analysis of Glycosides.

    PubMed

    Giner, José-Luis; Feng, Ju; Kiemle, David J

    2016-09-23

    The sugar subunits of natural glycosides can be conveniently determined by acid hydrolysis and (1)H NMR spectroscopy without isolation or derivatization. The chemical shifts, coupling constants, and integral ratios of the anomeric signals allow each monosaccharide to be identified and its molar ratio to other monosaccharides to be quantified. The NMR data for the anomeric signals of 28 monosaccharides and three disaccharides are reported. Application of the method is demonstrated with the flavonoid glycoside naringin (1), the aminoglycoside antibiotics kanamycin (2) and tobramycin (3), and the saponin digitonin (4). PMID:27603739

  5. Complete 1H NMR spectral analysis of ten chemical markers of Ginkgo biloba

    PubMed Central

    Napolitano, José G.; Lankin, David C.; Chen, Shao-Nong; Pauli, Guido F.

    2013-01-01

    The complete and unambiguous 1H NMR assignments of ten marker constituents of Ginkgo biloba are described. The comprehensive 1H NMR profiles (fingerprints) of ginkgolide A, ginkgolide B, ginkgolide C, ginkgolide J, bilobalide, quercetin, kaempferol, isorhamnetin, isoquercetin, and rutin in DMSO-d6 were obtained through the examination of 1D 1H NMR and 2D 1H,1H-COSY data, in combination with 1H iterative Full Spin Analysis (HiFSA). The computational analysis of discrete spin systems allowed a detailed characterization of all the 1H NMR signals in terms of chemical shifts (δH) and spin-spin coupling constants (JHH), regardless of signal overlap and higher order coupling effects. The capability of the HiFSA-generated 1H fingerprints to reproduce experimental 1H NMR spectra at different field strengths was also evaluated. As a result of this analysis, a revised set of 1H NMR parameters for all ten phytoconstituents was assembled. Furthermore, precise 1H NMR assignments of the sugar moieties of isoquercetin and rutin are reported for the first time. PMID:22730238

  6. Statistical models and NMR analysis of polymer microstructure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Statistical models can be used in conjunction with NMR spectroscopy to study polymer microstructure and polymerization mechanisms. Thus, Bernoullian, Markovian, and enantiomorphic-site models are well known. Many additional models have been formulated over the years for additional situations. Typica...

  7. A Wet-Lab Approach to Stereochemistry Using [superscript 31]P NMR Spectroscopy

    ERIC Educational Resources Information Center

    Fenton, Owen S.; Sculimbrene, Bianca R.

    2011-01-01

    Understanding stereochemistry is an important and difficult task for students to master in organic chemistry. In both introductory and advanced courses, students are encouraged to explore the spatial relationships between molecules, but this exploration is often limited either to the lecture hall or the confines of the library. As such, we sought…

  8. Evaluation of a New 1H/31P Dual-Tuned Birdcage Coil for 31P Spectroscopy

    PubMed Central

    Potter, WM; Wang, L; McCully, KK; Zhao, Q

    2013-01-01

    We introduce a new dual-tuned Hydrogen/Phosphorus (1H/31P) birdcage coil, referred to as split birdcage coil, and evaluate its performance using both simulations and magnetic resonance (MR) experiments on a 3 T MR scanner. The proposed coil simplifies the practical matters of tuning and matching, which makes the coil easily reproducible. Simulations were run with the Finite Difference in Time Domain (FDTD) method to evaluate the sensitivity and homogeneity of the magnetic field generated by the proposed 1H coils. Following simulations, MR experiments were conducted using both a phantom and human thigh to compare the proposed design with a currently available commercial dual-tuned flexible surface coil, referred to as flex surface coil, for signal to noise ratio (SNR) as well as homogeneity for the 31P coil. At regions deep within the human thigh, the split birdcage coil was able to acquire spectroscopic signal with a higher average SNR than the flex surface coil. For all regions except those close to the flex surface coil, the split birdcage coil matched or exceeded the performance of the flex surface coil. PMID:24039555

  9. Differential cross sections measurement of 31P(p,pγ1)31P reaction for PIGE applications

    NASA Astrophysics Data System (ADS)

    Jokar, A.; Kakuee, O.; Lamehi-Rachti, M.

    2016-09-01

    Differential cross sections of proton induced gamma-ray emission from the 31P(p,pγ1)31P (Eγ = 1266 keV) nuclear reaction were measured in the proton energy range of 1886-3007 keV at the laboratory angle of 90°. For these measurements a thin Zn3P2 target evaporated onto a self-supporting C film was used. The gamma-rays and backscattered protons were detected simultaneously. An HPGe detector placed at an angle of 90° with respect to the beam direction was employed to collect gamma-rays while an ion implanted Si detector placed at a scattering angle of 165° was used to detect backscattered protons. Simultaneous collection of gamma-rays and RBS spectra is a great advantage of this approach which makes differential cross-section measurements independent on the collected beam charge. The obtained cross-sections were compared with the previously only measured data in the literature. The validity of the measured differential cross sections was verified through a thick target benchmarking experiment. The overall systematic uncertainty of cross section values was estimated to be better than ±9%.

  10. Nmrglue: An Open Source Python Package for the Analysis of Multidimensional NMR Data

    PubMed Central

    Helmus, Jonathan J.; Jaroniec, Christopher P.

    2013-01-01

    Nmrglue, an open source Python package for working with multidimensional NMR data, is described. When used in combination with other Python scientific libraries, nmrglue provides a highly flexible and robust environment for spectral processing, analysis and visualization and includes a number of common utilities such as linear prediction, peak picking and lineshape fitting. The package also enables existing NMR software programs to be readily tied together, currently facilitating the reading, writing and conversion of data stored in Bruker, Agilent/Varian, NMRPipe, Sparky, SIMPSON, and Rowland NMR Toolkit file formats. In addition to standard applications, the versatility offered by nmrglue makes the package particularly suitable for tasks that include manipulating raw spectrometer data files, automated quantitative analysis of multidimensional NMR spectra with irregular lineshapes such as those frequently encountered in the context of biomacromolecular solid-state NMR, and rapid implementation and development of unconventional data processing methods such as covariance NMR and other non-Fourier approaches. Detailed documentation, install files and source code for nmrglue are freely available at http://nmrglue.com. The source code can be redistributed and modified under the New BSD license. PMID:23456039

  11. Anisotropic nuclear spin interactions for the morphology analysis of proteins in solution by NMR spectroscopy.

    PubMed

    Tate, Shin-Ichi

    2008-01-01

    Determining the relative orientation of domains within a protein is an important problem in structural biology, which has been difficult to address by either X-ray crystallography or NMR. The structure of a multidomain protein in a crystal lattice can be altered by crystal packing forces, resulting in different domain arrangements from those in solution. On the other hand, conventional NMR primarily provides short-range structural information, including proton-proton distances derived from nuclear Overhauser effects (NOEs) and torsion angles through vicinal spin couplings. Thus, NMR cannot always determine the precise interdomain arrangements due to the sparsely observed spin interactions between domains. However, the weak alignment of proteins in solution has enabled a new NMR technique to determine the domain arrangement based on the different structural information, which defines the orientation of a structural unit in protein against the magnetic field. This technique relies on the anisotropic nuclear spin interactions that only occur for a molecule in a weakly aligned state. In this review, the basics of the new NMR approach are described with focusing on its application to domain orientation analysis. We also describe our recently established NMR approach using the same spin interactions, which expands the domain arrangement analysis to higher-molecular weight proteins over 100 kDa.

  12. Nmrglue: an open source Python package for the analysis of multidimensional NMR data.

    PubMed

    Helmus, Jonathan J; Jaroniec, Christopher P

    2013-04-01

    Nmrglue, an open source Python package for working with multidimensional NMR data, is described. When used in combination with other Python scientific libraries, nmrglue provides a highly flexible and robust environment for spectral processing, analysis and visualization and includes a number of common utilities such as linear prediction, peak picking and lineshape fitting. The package also enables existing NMR software programs to be readily tied together, currently facilitating the reading, writing and conversion of data stored in Bruker, Agilent/Varian, NMRPipe, Sparky, SIMPSON, and Rowland NMR Toolkit file formats. In addition to standard applications, the versatility offered by nmrglue makes the package particularly suitable for tasks that include manipulating raw spectrometer data files, automated quantitative analysis of multidimensional NMR spectra with irregular lineshapes such as those frequently encountered in the context of biomacromolecular solid-state NMR, and rapid implementation and development of unconventional data processing methods such as covariance NMR and other non-Fourier approaches. Detailed documentation, install files and source code for nmrglue are freely available at http://nmrglue.com. The source code can be redistributed and modified under the New BSD license.

  13. 31P magnetization transfer measurements of Pi→ATP flux in exercising human muscle.

    PubMed

    Sleigh, Alison; Savage, David B; Williams, Guy B; Porter, David; Carpenter, T Adrian; Brindle, Kevin M; Kemp, Graham J

    2016-03-15

    Fundamental criticisms have been made over the use of (31)P magnetic resonance spectroscopy (MRS) magnetization transfer estimates of inorganic phosphate (Pi)→ATP flux (VPi-ATP) in human resting skeletal muscle for assessing mitochondrial function. Although the discrepancy in the magnitude of VPi-ATP is now acknowledged, little is known about its metabolic determinants. Here we use a novel protocol to measure VPi-ATP in human exercising muscle for the first time. Steady-state VPi-ATP was measured at rest and over a range of exercise intensities and compared with suprabasal oxidative ATP synthesis rates estimated from the initial rates of postexercise phosphocreatine resynthesis (VATP). We define a surplus Pi→ATP flux as the difference between VPi-ATP and VATP. The coupled reactions catalyzed by the glycolytic enzymes GAPDH and phosphoglycerate kinase (PGK) have been shown to catalyze measurable exchange between ATP and Pi in some systems and have been suggested to be responsible for this surplus flux. Surplus VPi-ATP did not change between rest and exercise, even though the concentrations of Pi and ADP, which are substrates for GAPDH and PGK, respectively, increased as expected. However, involvement of these enzymes is suggested by correlations between absolute and surplus Pi→ATP flux, both at rest and during exercise, and the intensity of the phosphomonoester peak in the (31)P NMR spectrum. This peak includes contributions from sugar phosphates in the glycolytic pathway, and changes in its intensity may indicate changes in downstream glycolytic intermediates, including 3-phosphoglycerate, which has been shown to influence the exchange between ATP and Pi catalyzed by GAPDH and PGK. PMID:26744504

  14. 31P magnetization transfer measurements of Pi→ATP flux in exercising human muscle.

    PubMed

    Sleigh, Alison; Savage, David B; Williams, Guy B; Porter, David; Carpenter, T Adrian; Brindle, Kevin M; Kemp, Graham J

    2016-03-15

    Fundamental criticisms have been made over the use of (31)P magnetic resonance spectroscopy (MRS) magnetization transfer estimates of inorganic phosphate (Pi)→ATP flux (VPi-ATP) in human resting skeletal muscle for assessing mitochondrial function. Although the discrepancy in the magnitude of VPi-ATP is now acknowledged, little is known about its metabolic determinants. Here we use a novel protocol to measure VPi-ATP in human exercising muscle for the first time. Steady-state VPi-ATP was measured at rest and over a range of exercise intensities and compared with suprabasal oxidative ATP synthesis rates estimated from the initial rates of postexercise phosphocreatine resynthesis (VATP). We define a surplus Pi→ATP flux as the difference between VPi-ATP and VATP. The coupled reactions catalyzed by the glycolytic enzymes GAPDH and phosphoglycerate kinase (PGK) have been shown to catalyze measurable exchange between ATP and Pi in some systems and have been suggested to be responsible for this surplus flux. Surplus VPi-ATP did not change between rest and exercise, even though the concentrations of Pi and ADP, which are substrates for GAPDH and PGK, respectively, increased as expected. However, involvement of these enzymes is suggested by correlations between absolute and surplus Pi→ATP flux, both at rest and during exercise, and the intensity of the phosphomonoester peak in the (31)P NMR spectrum. This peak includes contributions from sugar phosphates in the glycolytic pathway, and changes in its intensity may indicate changes in downstream glycolytic intermediates, including 3-phosphoglycerate, which has been shown to influence the exchange between ATP and Pi catalyzed by GAPDH and PGK.

  15. Growth and preparation of Staphylococcus epidermidis for NMR metabolomic analysis.

    PubMed

    Somerville, Greg A; Powers, Robert

    2014-01-01

    The "omics" era began with transcriptomics and this progressed into proteomics. While useful, these approaches provide only circumstantial information about carbon flow, metabolic status, redox poise, etc. To more directly address these metabolic concerns, researchers have turned to the emerging field of metabolomics. In our laboratories, we frequently use NMR metabolomics to acquire a snapshot of bacterial metabolomes during stressful or transition events. Irrespective of the "omics" method of choice, the experimental outcome depends on the proper cultivation and preparation of bacterial samples. In addition, the integration of these large datasets requires that these cultivation conditions be clearly defined.

  16. NMR analysis of base-pair opening kinetics in DNA.

    PubMed

    Szulik, Marta W; Voehler, Markus; Stone, Michael P

    2014-12-12

    Base pairing in nucleic acids plays a crucial role in their structure and function. Differences in the base-pair opening and closing kinetics of individual double-stranded DNA sequences or between chemically modified base pairs provide insight into the recognition of these base pairs by DNA processing enzymes. This unit describes how to quantify the kinetics for localized base pairs by observing changes in the imino proton signals by nuclear magnetic resonance spectroscopy. The determination of all relevant parameters using state-of-the art techniques and NMR instrumentation, including cryoprobes, is discussed.

  17. Dissociation behavior of Methane Hydrate presumed by NMR log analysis

    NASA Astrophysics Data System (ADS)

    Kotera, T.

    2015-12-01

    This study has been conducted with the aim of comprehending dissociation behavior of MH. The production test was operated in the Daini-Atsumi knoll in the eastern Nankai Trough, Japan. We corresponded the NMR log data acquired from the three wells, which drilled before the test (AT1-MC) and after the test (AT1-LWD1 and AT1-LWD2). NMR log measures T2 relaxation time, and calculates porosity and permeability. We especially focused on the T2 distribution. It is assumed that MH occupied larger pore space in the sandy sediment because the T2 distribution in the MH bearing layer has no peak in the longer time zone at the AT1-MC. However, T2 peak appeared over 33ms zone at the AT1-LWD1 and AT1-LWD2. This phenomenon is observed in the thin MH bearing layers rather than thick one. On the other hand, nothing T2 peak appeared over the 33ms zone in the thick MH bearing layer, but T2 distribution shifts to longer relaxation time in the short time interval. Hence, it is assumed that the MH was dissociated from the contact faces with the grain. In terms of the thermal conductivity, near the grain-grain contact faces are more dissociable than the MH-grain contact; however both of dissociation zones are essentially MH-grain contact faces. Nothing or few MH was observed in the muddy layer at the coring campaign near these wells. Abovementioned, NMR logging detected various changes on the T2 distribution. It seems to indicate the dissociation of MH. And these data gets into alignment with other log data and monitoring data, which are resistivity and temperature measurement. However, as this logging data acquired from each location, there is possibility that the initial condition was originally distinct. This research was conducted as a part of the MH21 research, and the authors would like to express their sincere appreciation to MH21 and the Ministry of Economy, Trade and Industry for providing the permission to disclose this research.

  18. (1) H NMR analysis of O-methyl-inositol isomers: a joint experimental and theoretical study.

    PubMed

    De Almeida, Mauro V; Couri, Mara Rubia C; De Assis, João Vitor; Anconi, Cleber P A; Dos Santos, Hélio F; De Almeida, Wagner B

    2012-09-01

    Density functional theory (DFT) calculations of (1) H NMR chemical shifts for l-quebrachitol isomers were performed using the B3LYP functional employing the 6-31G(d,p) and 6-311 + G(2d,p) basis sets. The effect of the solvent on the B3LYP-calculated NMR spectrum was accounted for using the polarizable continuum model. Comparison is made with experimental (1) H NMR spectroscopic data, which shed light on the average uncertainty present in DFT calculations of chemical shifts and showed that the best match between experimental and theoretical B3LYP (1) H NMR profiles is a good strategy to assign the molecular structure present in the sample handled in the experimental measurements. Among four plausible O-methyl-inositol isomers, the l-quebrachitol 2a structure was unambiguously assigned based only on the comparative analysis of experimental and theoretical (1) H NMR chemical shift data. The B3LYP infrared (IR) spectrum was also calculated for the four isomers and compared with the experimental data, with analysis of the theoretical IR profiles corroborating assignment of the 2a structure. Therefore, it is confirmed in this study that a combined experimental/DFT spectroscopic investigation is a powerful tool in structural/conformational analysis studies. PMID:22865668

  19. (1) H NMR analysis of O-methyl-inositol isomers: a joint experimental and theoretical study.

    PubMed

    De Almeida, Mauro V; Couri, Mara Rubia C; De Assis, João Vitor; Anconi, Cleber P A; Dos Santos, Hélio F; De Almeida, Wagner B

    2012-09-01

    Density functional theory (DFT) calculations of (1) H NMR chemical shifts for l-quebrachitol isomers were performed using the B3LYP functional employing the 6-31G(d,p) and 6-311 + G(2d,p) basis sets. The effect of the solvent on the B3LYP-calculated NMR spectrum was accounted for using the polarizable continuum model. Comparison is made with experimental (1) H NMR spectroscopic data, which shed light on the average uncertainty present in DFT calculations of chemical shifts and showed that the best match between experimental and theoretical B3LYP (1) H NMR profiles is a good strategy to assign the molecular structure present in the sample handled in the experimental measurements. Among four plausible O-methyl-inositol isomers, the l-quebrachitol 2a structure was unambiguously assigned based only on the comparative analysis of experimental and theoretical (1) H NMR chemical shift data. The B3LYP infrared (IR) spectrum was also calculated for the four isomers and compared with the experimental data, with analysis of the theoretical IR profiles corroborating assignment of the 2a structure. Therefore, it is confirmed in this study that a combined experimental/DFT spectroscopic investigation is a powerful tool in structural/conformational analysis studies.

  20. Comprehensive NMR analysis of compositional changes of black garlic during thermal processing.

    PubMed

    Liang, Tingfu; Wei, Feifei; Lu, Yi; Kodani, Yoshinori; Nakada, Mitsuhiko; Miyakawa, Takuya; Tanokura, Masaru

    2015-01-21

    Black garlic is a processed food product obtained by subjecting whole raw garlic to thermal processing that causes chemical reactions, such as the Maillard reaction, which change the composition of the garlic. In this paper, we report a nuclear magnetic resonance (NMR)-based comprehensive analysis of raw garlic and black garlic extracts to determine the compositional changes resulting from thermal processing. (1)H NMR spectra with a detailed signal assignment showed that 38 components were altered by thermal processing of raw garlic. For example, the contents of 11 l-amino acids increased during the first step of thermal processing over 5 days and then decreased. Multivariate data analysis revealed changes in the contents of fructose, glucose, acetic acid, formic acid, pyroglutamic acid, cycloalliin, and 5-(hydroxymethyl)furfural (5-HMF). Our results provide comprehensive information on changes in NMR-detectable components during thermal processing of whole garlic. PMID:25549134

  1. Comprehensive NMR analysis of compositional changes of black garlic during thermal processing.

    PubMed

    Liang, Tingfu; Wei, Feifei; Lu, Yi; Kodani, Yoshinori; Nakada, Mitsuhiko; Miyakawa, Takuya; Tanokura, Masaru

    2015-01-21

    Black garlic is a processed food product obtained by subjecting whole raw garlic to thermal processing that causes chemical reactions, such as the Maillard reaction, which change the composition of the garlic. In this paper, we report a nuclear magnetic resonance (NMR)-based comprehensive analysis of raw garlic and black garlic extracts to determine the compositional changes resulting from thermal processing. (1)H NMR spectra with a detailed signal assignment showed that 38 components were altered by thermal processing of raw garlic. For example, the contents of 11 l-amino acids increased during the first step of thermal processing over 5 days and then decreased. Multivariate data analysis revealed changes in the contents of fructose, glucose, acetic acid, formic acid, pyroglutamic acid, cycloalliin, and 5-(hydroxymethyl)furfural (5-HMF). Our results provide comprehensive information on changes in NMR-detectable components during thermal processing of whole garlic.

  2. High-throughput microcoil NMR of compound libraries using zero-dispersion segmented flow analysis.

    PubMed

    Kautz, Roger A; Goetzinger, Wolfgang K; Karger, Barry L

    2005-01-01

    An automated system for loading samples into a microcoil NMR probe has been developed using segmented flow analysis. This approach enhanced 2-fold the throughput of the published direct injection and flow injection methods, improved sample utilization 3-fold, and was applicable to high-field NMR facilities with long transfer lines between the sample handler and NMR magnet. Sample volumes of 2 microL (10-30 mM, approximately 10 microg) were drawn from a 96-well microtiter plate by a sample handler, then pumped to a 0.5-microL microcoil NMR probe as a queue of closely spaced "plugs" separated by an immiscible fluorocarbon fluid. Individual sample plugs were detected by their NMR signal and automatically positioned for stopped-flow data acquisition. The sample in the NMR coil could be changed within 35 s by advancing the queue. The fluorocarbon liquid wetted the wall of the Teflon transfer line, preventing the DMSO samples from contacting the capillary wall and thus reducing sample losses to below 5% after passage through the 3-m transfer line. With a wash plug of solvent between samples, sample-to-sample carryover was <1%. Significantly, the samples did not disperse into the carrier liquid during loading or during acquisitions of several days for trace analysis. For automated high-throughput analysis using a 16-second acquisition time, spectra were recorded at a rate of 1.5 min/sample and total deuterated solvent consumption was <0.5 mL (1 US dollar) per 96-well plate.

  3. Quantitative and dynamic analysis of PTEN phosphorylation by NMR.

    PubMed

    Cordier, Florence; Chaffotte, Alain; Wolff, Nicolas

    2015-05-01

    The dual lipid and protein phosphatase PTEN is a tumor suppressor controlling key biological processes, such as cell growth, proliferation and neuro-survival. Its activity and intracellular trafficking is finely regulated notably by multi-site phosphorylation of its C-terminal tail. The reversible and highly dynamic character of these regulatory events confers a temporal dimension to the cell for triggering crucial decisions. In this review, we describe how a recently developed time-resolved NMR spectroscopy approach unveils the dynamic establishment of the phosphorylation events of PTEN C-terminal tail controlled by CK2 and GSK3β kinases. Two cascades of reactions have been identified, in vitro and in extracts of human neuroblastoma cells. They are triggered independently on two nearby clusters of sites (S380-S385 and S361-S370) and occur on different timescales. In each cascade, the reactions follow an ordered model with a distributive kinetic mechanism. The vision of these cascades as two delay timers activating distinct or time-delayed regulatory responses gives a temporal dimension on PTEN regulation and is discussed in relation to the known functional roles of each cluster. PMID:25449899

  4. Water transfer analysis in pork meat supported by NMR imaging.

    PubMed

    Ruiz-Cabrera, M A; Gou, P; Foucat, L; Renou, J P; Daudin, J D

    2004-05-01

    NMR proton density imaging was used to study isothermal and unidirectional drying of pork semi membranosus muscle samples at temperatures of 12, 16 and 20 °C. An independent calibration of the transversal relaxation time T(2) as a function of the moisture content was carried out to convert the signal amplitude into moisture content. Due to spatial heterogeneity in drying, 2D images were needed to assess the evolution of 1D moisture profiles. The relationship between the effective water diffusivity (D) was calculated in function of water content (X) using the Boltzman transformation which needs no a priori on the relationship D=f(X); the effect of lipid content, temperature and fibre direction on this relationship were also studied. In all cases a decrease in water content brought about a decrease in D. A slight increase in lipid content led to a dramatic decrease in D. The fibre direction relative to water movement had a negligible effect. No significative differences in D between the three temperatures were observed, due to variability in the chemical composition of the samples. PMID:22061130

  5. NMR structural analysis of Sleeping Beauty transposase binding to DNA

    PubMed Central

    E Carpentier, Claire; Schreifels, Jeffrey M; Aronovich, Elena L; Carlson, Daniel F; Hackett, Perry B; Nesmelova, Irina V

    2014-01-01

    The Sleeping Beauty (SB) transposon is the most widely used DNA transposon in genetic applications and is the only DNA transposon thus far in clinical trials for human gene therapy. In the absence of atomic level structural information, the development of SB transposon relied primarily on the biochemical and genetic homology data. While these studies were successful and have yielded hyperactive transposases, structural information is needed to gain a mechanistic understanding of transposase activity and guides to further improvement. We have initiated a structural study of SB transposase using Nuclear Magnetic Resonance (NMR) and Circular Dichroism (CD) spectroscopy to investigate the properties of the DNA-binding domain of SB transposase in solution. We show that at physiologic salt concentrations, the SB DNA-binding domain remains mostly unstructured but its N-terminal PAI subdomain forms a compact, three-helical structure with a helix-turn-helix motif at higher concentrations of NaCl. Furthermore, we show that the full-length SB DNA-binding domain associates differently with inner and outer binding sites of the transposon DNA. We also show that the PAI subdomain of SB DNA-binding domain has a dominant role in transposase's attachment to the inverted terminal repeats of the transposon DNA. Overall, our data validate several earlier predictions and provide new insights on how SB transposase recognizes transposon DNA. PMID:24243759

  6. Analysis of human muscle extracts by proton NMR

    SciTech Connect

    Venkatasubramanian, P.N.; Barany, M.; Arus, C.

    1986-03-01

    Perchloric acid extracts were prepared from pooled human muscle biopsies from patients diagnosed with scoliosis (SCOL) and cerebral palsy (CP). After neutralization with KOH and removal of perchlorate, the extracts were concentrated by freeze drying and dissolved in /sup 2/H/sub 2/O to contain 120 O.D. units at 280 nm per 0.5 ml. /sup 1/H NMR spectroscopy was performed with the 5 mm probe of a Varian XL300 instrument. Creatine, lactate, carnosine, and choline were the major resonances in the one-dimensional spectra of both extracts. With creatine as reference, 2.5-fold more lactate was found in SCOL than in CP, and a much smaller difference was also found in their carnosine content. Two-dimensional COSY comparison revealed several differences between the two extracts. Taurine, N-acetyl glutamate, glycerophosphoryl choline (or phosphoryl choline) and an unidentified spot were present only in the extract from SCOL but not in that from CP. On the other hand, aspartate, hydroxy-proline, carnitine and glycerophosphoryl ethanolamine were only present in CP but absent in SCOL. Alanine, cysteine, lysine and arginine appeared in both extracts without an apparent intensity difference.

  7. Extraction, Purification, and NMR Analysis of Terpenes from Brown Algae.

    PubMed

    Gaysinski, Marc; Ortalo-Magné, Annick; Thomas, Olivier P; Culioli, Gérald

    2015-01-01

    Algal terpenes constitute a wide and well-documented group of marine natural products with structures differing from their terrestrial plant biosynthetic analogues. Amongst macroalgae, brown seaweeds are considered as one of the richest source of biologically and ecologically relevant terpenoids. These metabolites, mostly encountered in algae of the class Phaeophyceae, are mainly diterpenes and meroditerpenes (metabolites of mixed biogenesis characterized by a toluquinol or a toluquinone nucleus linked to a diterpene moiety).In this chapter, we describe analytical processes commonly employed for the isolation and structural characterization of the main terpenoid constituents obtained from organic extracts of brown algae. The successive steps include (1) extraction of lipidic content from algal samples; (2) purification of terpenes by column chromatography and semi-preparative high-performance liquid chromatography; and (3) structure elucidation of the isolated terpenes by means of 1D and 2D nuclear magnetic resonance (NMR). More precisely, we propose a representative methodology which allows the isolation and structural determination of the monocyclic meroditerpene methoxybifurcarenone (MBFC) from the Mediterranean brown alga Cystoseira amentacea var. stricta. This methodology has a large field of applications and can then be extended to terpenes isolated from other species of the family Sargassaceae.

  8. Magic Angle Spinning NMR Spectroscopy: A Versatile Technique for Structural and Dynamic Analysis of Solid-Phase Systems

    PubMed Central

    Polenova, Tatyana; Gupta, Rupal; Goldbourt, Amir

    2016-01-01

    Magic Angle Spinning (MAS) NMR spectroscopy is a powerful method for analysis of a broad range of systems, including inorganic materials, pharmaceuticals, and biomacromolecules. The recent developments in MAS NMR instrumentation and methodologies opened new vistas to atomic-level characterization of a plethora of chemical environments previously inaccessible to analysis, with unprecedented sensitivity and resolution. PMID:25794311

  9. 4 T Actively detuneable double-tuned 1H/31P head volume coil and four-channel 31P phased array for human brain spectroscopy.

    PubMed

    Avdievich, N I; Hetherington, H P

    2007-06-01

    Typically 31P in vivo magnetic resonance spectroscopic studies are limited by SNR considerations. Although phased arrays can improve the SNR; to date 31P phased arrays for high-field systems have not been combined with 31P volume transmit coils. Additionally, to provide anatomical reference for the 31P studies, without removal of the coil or patient from the magnet, double-tuning (31P/1H) of the volume coil is required. In this work we describe a series of methods for active detuning and decoupling enabling use of phased arrays with double-tuned volume coils. To demonstrate these principles we have built and characterized an actively detuneable 31P/1H TEM volume transmit/four-channel 31P phased array for 4 T magnetic resonance spectroscopic imaging (MRSI) of the human brain. The coil can be used either in volume-transmit/array-receive mode or in TEM transmit/receive mode with the array detuned. Threefold SNR improvement was obtained at the periphery of the brain using the phased array as compared to the volume coil. PMID:17379554

  10. Transport of phosphocholine in higher plant cells: sup 31 P nuclear magnetic resonance studies

    SciTech Connect

    Gout, E.; Bligny, R.; Roby, C.; Douce, R. )

    1990-06-01

    Phosphocholine (PC) is an abundant primary form of organic phosphate that is transported in plant xylem sap. Addition of PC to the perfusate of compressed P{sub i}-starved sycamore cells monitored by {sup 31}P NMR spectroscopy resulted in an accumulation of PC and all the other phosphate esters in the cytoplasmic compartment. Addition of hemicholinium-3, an inhibitor of choline uptake, to the perfusate inhibited PC accumulation but not inorganic phosphate (P{sub i}). When the P{sub i}-starved cells were perfused with a medium containing either P{sub i} or PC, the resulting P{sub i} distribution in the cell was the same. Addition of choline instead of PC to the perfusate of compressed cells resulted in an accumulation of PC in the cytoplasmic compartment from choline kinase activity. In addition, PC phosphatase activity has been discovered associated with the cell wall. These results indicate that PC was rapidly hydrolyzed outside the cell and that choline and P{sub i} entered the cytosolic compartment where choline kinase re-forms PC.

  11. A simple protocol for NMR analysis of the enantiomeric purity of chiral hydroxylamines.

    PubMed

    Tickell, David A; Mahon, Mary F; Bull, Steven D; James, Tony D

    2013-02-15

    A practically simple three-component chiral derivatization protocol for determining the enantiopurity of chiral hydroxylamines by (1)H NMR spectroscopic analysis is described, involving their treatment with 2-formylphenylboronic acid and enantiopure BINOL to afford a mixture of diastereomeric nitrono-boronate esters whose ratio is an accurate reflection of the enantiopurity of the parent hydroxylamine.

  12. Characterizing biomass fast pyrolysis oils by 13C-NMR and chemometric analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several biomass fast pyrolysis oils were characterized by 13C and DEPT NMR analysis to determine chemical functional group compositions as related to their energy content. Pyrolysis oils were produced from a variety of feedstocks including energy crops, woods, animal wastes and oil seed presscakes,...

  13. NMR analysis of sequence of toxin II from the sea anemone Radianthus paumotensis

    SciTech Connect

    Wemmer, D.E.; Kumar, N.V.; Metrione, R.M.; Lazdunski, M.; Drobny, G.; Kallenbach, N.R.

    1986-11-04

    Toxin II from Radianthus paumotensis (Rp/sub II/) has been investigated by high-resolution NMR and chemical sequencing methods. Resonance assignments have been obtained for this protein by the sequential approach. NMR assignments could not be made consistent with the previously reported primary sequence for this protein, and chemical methods have been used to determine a sequence with which the NMR data are consistent. Analysis of the 2D NOE spectra shows that the protein secondary structure is comprised of two sequences of ..beta..-sheet, probably joined into a distorted continuous sheet, connected by turns and extended loops, without any regular ..cap alpha..-helical segments. The residues previously implicated in activity in this class of proteins, D8 and R13, occur in a loop region.

  14. NMR analysis of tertiary interactions in HDV ribozymes.

    PubMed

    Tanaka, Y; Hori, T; Tagaya, M; Katahira, M; Nishikawa, F; Sakamoto, T; Kurihara, Y; Nishikawa, S; Uesugi, S

    2000-01-01

    Three variants of minimized hepatitis delta virus (HDV) RNA ribozyme systems designed on the basis of the "pseudoknot" model were synthesized and their tertiary interactions were analyzed by NMR spectroscopy. Rz-1 is a cis-acting ribozyme system (the cleaved form, 56-mer) in which stem IV is deleted from the active domain of genomic HDV RNA. Rz-1 was uniformly labeled with stable isotopes, 13C and 15N. Rz-2 is a trans-acting ribozyme system (substrate: 8-mer, the cytidine residue at the cleavage site is replaced by 2'-O-methylcytidine; enzyme: 16-mer plus 35-mer). Rz-2 was partially labeled with stable isotopes in guanosine residues of enzyme 35mer. Rz-4 is a trans-acting ribozyme system (substrate: 8mer, the cytidine residue at the cleavage site is replaced by 2'-O-methylcytidine; enzyme 53mer) which was designed by Perrotta and Been. Rz-4 has the same sequence and an extra loop closing stem IV. From 2D-NOESY and 2D-HSQC (except for Rz-4) spectra, it was suggested each ribozyme forms "pseudoknot" type structure in solution. Additionally, it was found that G38 of Rz-1, G28 and G29 of Rz-2 and Rz-4 form base-pairs. These novel base-pairs are observed in the crystal structure of a modified genomic HDV RNA. From temperature change experiment of Rz-2, the imino proton signal of G28 disappeared at 50 degrees C earlier than the other corresponding signals. Upon MgCl2 titration of Rz-2, this signal showed the largest shift.

  15. Functional group analysis in coal and on coal surfaces by NMR spectroscopy

    SciTech Connect

    Verkade, J.G.

    1989-10-01

    The reaction of Cl{ovr POCH{sub 2}CH{sub 2}O} (2) with moisture in pyridine extracts of Argonne standard coal samples has been found to give results comparable with the ASTM D3302 moisture analyses of these samples. Differences in the two sets of results are discussed. Some exceptionally large solvent effects on {sup 31}P chemical shifts of model compounds derivatized with 2 and 8 have been discovered. Initial experiments aimed at labile hydrogen functional group analysis of solid coal samples with 2 and Me{sub 2}N{ovr POCH{sub 2}CH{sub 2}O} (15) are described. 17 refs., 1 fig., 6 tabs.

  16. The program XEASY for computer-supported NMR spectral analysis of biological macromolecules.

    PubMed

    Bartels, C; Xia, T H; Billeter, M; Güntert, P; Wüthrich, K

    1995-07-01

    A new program package, XEASY, was written for interactive computer support of the analysis of NMR spectra for three-dimensional structure determination of biological macromolecules. XEASY was developed for work with 2D, 3D and 4D NMR data sets. It includes all the functions performed by the precursor program EASY, which was designed for the analysis of 2D NMR spectra, i.e., peak picking and support of sequence-specific resonance assignments, cross-peak assignments, cross-peak integration and rate constant determination for dynamic processes. Since the program utilizes the X-window system and the Motif widget set, it is portable on a wide range of UNIX workstations. The design objective was to provide maximal computer support for the analysis of spectra, while providing the user with complete control over the final resonance assignments. Technically important features of XEASY are the use and flexible visual display of 'strips', i.e., two-dimensional spectral regions that contain the relevant parts of 3D or 4D NMR spectra, automated sorting routines to narrow down the selection of strips that need to be interactively considered in a particular assignment step, a protocol of resonance assignments that can be used for reliable bookkeeping, independent of the assignment strategy used, and capabilities for proper treatment of spectral folding and efficient transfer of resonance assignments between spectra of different types and different dimensionality, including projected, reduced-dimensionality triple-resonance experiments.

  17. The Quantitative Analysis of an Analgesic Tablet: An NMR Experiment for the Instrumental Analysis Course

    NASA Astrophysics Data System (ADS)

    Schmedake, Thomas A.; Welch, Lawrence E.

    1996-11-01

    A quantitative analysis experiment is outlined that uses 13C NMR. Initial work utilizes a known compound (acenapthene) to assess the type of NMR experiment necessary to achieve a proportional response from all of the carbons in the compound. Both gated decoupling and inverse gated decoupling routines with a variety of delay times are inspected, in addition to investigation of paramagnetic additives in conjunction with inverse gated decoupling. Once the experiments with the known compound have illuminated the merits of the differing strategies for obtaining a proportional carbon response, a quantitative assessment of an unknown analgesic tablet is undertaken. The amounts of the two major components of the tablet, acetaminophen and aspirin, are determined following addition of an internal standard to the mixture. The carbon resonances emanating from each compound can be identified using spectra of the pure analgesic components and internal standard. Knowing the concentration of the internal standard and assuming a proportional response to all carbons in the sample allows calculation of the amount of both analytes in the analgesic tablets. Data from an initial laboratory trial is presented that illustrates the accuracy of the procedure.

  18. Synthesis and NMR Spectral Analysis of Amine Heterocycles: The Effect of Asymmetry on the [superscript 1]H and [superscript 13]C NMR Spectra of N,O-Acetals

    ERIC Educational Resources Information Center

    Saba, Shahrokh; Ciaccio, James A.; Espinal, Jennifer; Aman, Courtney E.

    2007-01-01

    The stereochemical investigation is conducted to give students the combined experience of chemical synthesis of amines and N-heterocycles and structural stereochemical analysis using NMR spectroscopy. Students are introduced to the concept of topicity-stereochemical relationships between ligands within a molecule by synthesizing N,O-acetals.

  19. Differences in Human Meibum Lipid Composition with Meibomian Gland Dysfunction Using NMR and Principal Component Analysis

    PubMed Central

    Foulks, Gary N.; Yappert, Marta C.; Milliner, Sarah E.

    2012-01-01

    Purpose. Nuclear magnetic resonance (NMR) spectroscopy has been used to quantify lipid wax, cholesterol ester terpenoid and glyceride composition, saturation, oxidation, and CH2 and CH3 moiety distribution. This tool was used to measure changes in human meibum composition with meibomian gland dysfunction (MGD). Methods. 1H-NMR spectra of meibum from 39 donors with meibomian gland dysfunction (Md) were compared to meibum from 33 normal donors (Mn). Results. Principal component analysis (PCA) was applied to the CH2/CH3 regions of a set of training NMR spectra of human meibum. PCA discriminated between Mn and Md with an accuracy of 86%. There was a bias toward more accurately predicting normal samples (92%) compared with predicting MGD samples (78%). When the NMR spectra of Md were compared with those of Mn, three statistically significant decreases were observed in the relative amounts of CH3 moieties at 1.26 ppm, the products of lipid oxidation above 7 ppm, and the ═CH moieties at 5.2 ppm associated with terpenoids. Conclusions. Loss of the terpenoids could be deleterious to meibum since they exhibit a plethora of mostly positive biological functions and could account for the lower level of cholesterol esters observed in Md compared with Mn. All three changes could account for the higher degree of lipid order of Md compared with age-matched Mn. In addition to the power of NMR spectroscopy to detect differences in the composition of meibum, it is promising that NMR can be used as a diagnostic tool. PMID:22131391

  20. Automated analysis of protein NMR assignments using methods from artificial intelligence.

    PubMed

    Zimmerman, D E; Kulikowski, C A; Huang, Y; Feng, W; Tashiro, M; Shimotakahara, S; Chien, C; Powers, R; Montelione, G T

    1997-06-20

    An expert system for determining resonance assignments from NMR spectra of proteins is described. Given the amino acid sequence, a two-dimensional 15N-1H heteronuclear correlation spectrum and seven to eight three-dimensional triple-resonance NMR spectra for seven proteins, AUTOASSIGN obtained an average of 98% of sequence-specific spin-system assignments with an error rate of less than 0.5%. Execution times on a Sparc 10 workstation varied from 16 seconds for smaller proteins with simple spectra to one to nine minutes for medium size proteins exhibiting numerous extra spin systems attributed to conformational isomerization. AUTOASSIGN combines symbolic constraint satisfaction methods with a domain-specific knowledge base to exploit the logical structure of the sequential assignment problem, the specific features of the various NMR experiments, and the expected chemical shift frequencies of different amino acids. The current implementation specializes in the analysis of data derived from the most sensitive of the currently available triple-resonance experiments. Potential extensions of the system for analysis of additional types of protein NMR data are also discussed.

  1. Structural fidelity and NMR relaxation analysis in a prototype RNA hairpin.

    PubMed

    Giambaşu, George M; York, Darrin M; Case, David A

    2015-05-01

    RNA hairpins are widespread and very stable motifs that contribute decisively to RNA folding and biological function. The GTP1G2C3A4C5U6U7C8G9G10U11G12C13C14 construct (with a central UUCG tetraloop) has been extensively studied by solution NMR, and offers and excellent opportunity to evaluate the structure and dynamical description afforded by molecular dynamics (MD) simulations. Here, we compare average structural parameters and NMR relaxation rates estimated from a series of multiple independent explicit solvent MD simulations using the two most recent RNA AMBER force fields (ff99 and ff10). Predicted overall tumbling times are ∼20% faster than those inferred from analysis of NMR data and follow the same trend when temperature and ionic strength is varied. The Watson-Crick stem and the "canonical" UUCG loop structure are maintained in most simulations including the characteristic syn conformation along the glycosidic bond of G9, although some key hydrogen bonds in the loop are partially disrupted. Our analysis pinpoints G9-G10 backbone conformations as a locus of discrepancies between experiment and simulation. In general the results for the more recent force-field parameters (ff10) are closer to experiment than those for the older ones (ff99). This work provides a comprehensive and detailed comparison of state of the art MD simulations against a wide variety of solution NMR measurements.

  2. MQ NMR and SPME analysis of nonlinearity in the degradation of a filled silicone elastomer

    SciTech Connect

    Chinn, S C; Alviso, C T; Berman, E S; Harvey, C A; Maxwell, R S; Wilson, T S; Cohenour, R; Saalwachter, K; Chasse, W

    2008-10-10

    Radiation induced degradation of polymeric materials occurs via numerous, simultaneous, competing chemical reactions. Though degradation is typically found to be linear in adsorbed dose, some silicone materials exhibit non-linear dose dependence due to dose dependent dominant degradation pathways. We have characterized the effects of radiative and thermal degradation on a model filled-PDMS system, Sylgard 184 (commonly used as an electronic encapsulant and in biomedical applications), using traditional mechanical testing, NMR spectroscopy, and sample headspace analysis using Solid Phase Micro-Extraction (SPME) followed by Gas Chromatography/Mass Spectrometry (GC/MS). The mechanical data and {sup 1}H spin-echo NMR indicated that radiation exposure leads to predominantly crosslinking over the cumulative dose range studies (0 to 250 kGray) with a rate roughly linear with dose. {sup 1}H Multiple Quantum NMR detected a bimodal distribution in the network structure, as expected by the proposed structure of Sylgard 184. The MQ-NMR further indicated that the radiation induced structural changes were not linear in adsorbed dose and competing chain scission mechanisms contribute more largely to the overall degradation process in the range of 50 -100 kGray (though crosslinking still dominates). The SPME-GC/MS data were analyzed using Principal Component Analysis (PCA), which identified subtle changes in the distributions of degradation products (the cyclic siloxanes and other components of the material) as a function of age that provide insight into the dominant degradation pathways at low and high adsorbed dose.

  3. Analytical solution of the time-dependent Bloch NMR flow equations: a translational mechanical analysis

    NASA Astrophysics Data System (ADS)

    Awojoyogbe, O. B.

    2004-08-01

    Various biological and physiological properties of living tissue can be studied by means of nuclear magnetic resonance techniques. Unfortunately, the basic physics of extracting the relevant information from the solution of Bloch nuclear magnetic resource (NMR) equations to accurately monitor the clinical state of biological systems is still not yet fully understood. Presently, there are no simple closed solutions known to the Bloch equations for a general RF excitation. Therefore the translational mechanical analysis of the Bloch NMR equations presented in this study, which can be taken as definitions of new functions to be studied in detail may reveal very important information from which various NMR flow parameters can be derived. Fortunately, many of the most important but hidden applications of blood flow parameters can be revealed without too much difficulty if appropriate mathematical techniques are used to solve the equations. In this study we are concerned with a mathematical study of the laws of NMR physics from the point of view of translational mechanical theory. The important contribution of this study is that solutions to the Bloch NMR flow equations do always exist and can be found as accurately as desired. We shall restrict our attention to cases where the radio frequency field can be treated by simple analytical methods. First we shall derive a time dependant second-order non-homogeneous linear differential equation from the Bloch NMR equation in term of the equilibrium magnetization M0, RF B1( t) field, T1 and T2 relaxation times. Then, we would develop a general method of solving the differential equation for the cases when RF B1( t)=0, and when RF B1( t)≠0. This allows us to obtain the intrinsic or natural behavior of the NMR system as well as the response of the system under investigation to a specific influence of external force to the system. Specifically, we consider the case where the RF B1 varies harmonically with time. Here the complete

  4. 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...

  5. Differential Analysis of 2D NMR Spectra: New Natural Products from a Pilot-Scale Fungal Extract Library

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a newly developed protocol for the differential analysis of arrays of 2D NMR spectra, we were able to rapidly identify two previously unreported indole alkaloids from a library of unfractionated fungal extracts. Differential analyses of NMR spectra thus constitute an effective tool for the non...

  6. Nanostructural analysis of water distribution in hydrated multicomponent gels using thermal analysis and NMR relaxometry.

    PubMed

    Codoni, Doroty; Belton, Peter; Qi, Sheng

    2015-06-01

    Highly complex, multicomponent gels and water-containing soft materials have varied applications in biomedical, pharmaceutical, and food sciences, but the characterization of these nanostructured materials is extremely challenging. The aim of this study was to use stearoyl macrogol-32 glycerides (Gelucire 50/13) gels containing seven different species of glycerides, PEG, and PEG-esters, as model, complex, multicomponent gels, to investigate the effect of water content on the micro- and nanoarchitecture of the gel interior. Thermal analysis and NMR relaxometry were used to probe the thermal and diffusional behavior of water molecules within the gel network. For the highly concentrated gels (low water content), the water activity was significantly lowered due to entrapment in the dense gel network. For the gels with intermediate water content, multiple populations of water molecules with different thermal responses and diffusion behavior were detected, indicating the presence of water in different microenvironments. This correlated with the network architecture of the freeze-dried gels observed using SEM. For the gels with high water content, increased quantities of water with similar diffusion characteristics as free water could be detected, indicating the presence of large water pockets in these gels. The results of this study provide new insights into structure of Gelucire gels, which have not been reported before because of the complexity of the material. They also demonstrate that the combination of thermal analysis and NMR relaxometry offers insights into the structure of soft materials not available by the use of each technique alone. However, we also note that in some instances the results of these measurements are overinterpreted and we suggest limitations of the methods that must be considered when using them.

  7. Metabolomic analysis of methyl jasmonate treated Brassica rapa leaves by 2-dimensional NMR spectroscopy.

    PubMed

    Liang, Yun-Sa; Choi, Young Hae; Kim, Hye Kyong; Linthorst, Huub J M; Verpoorte, Robert

    2006-11-01

    The metabolomic analysis of Brassica rapa leaves treated with methyl jasmonate was performed using 2-dimensional J-resolved NMR spectroscopy combined with multivariate data analysis. The principal component analysis of the J-resolved NMR spectra showed discrimination between control and methyl jasmonate treated plants by principal components 1 and 2. While the level of glucose, sucrose and amino acids showed a decrease after methyl jasmonate treatment, hydroxycinnamates and glucosinolate were highly increased. Methyl jasmonate treatment resulted in a long-term accumulation of indole glucosinolate and indole-3-acetic acid, lasting up to 14 days after treatment. Malate conjugated hydroxycinnamates also exhibited an increase until 14 days after methyl jasmonate treatment, these compounds might play an important role in plant defence responses mediated by methyl jasmonate.

  8. Advanced NMR-based techniques for pore structure analysis of coal

    SciTech Connect

    Smith, D.M.

    1992-01-01

    One of the main problems in coal utilization is the inability to properly characterize its complex pore structure. Coals typically have micro/ultra-micro pores but they also exhibit meso and macroporosity. Conventional pore size techniques (adsorption/condensation, mercury porosimetry) are limited because of this broad pore size range, microporosity, reactive nature of coal, samples must be completely dried, and network/percolation effects. Small angle scattering is limited because it probes both open and closed pores. Although one would not expect any single technique to provide a satisfactory description of a coal's structure, it is apparent that better techniques are necessary. We believe that measurement of the NMR parameters of various gas phase and adsorbed phase NMR active probes can provide the resolution to this problem. We will investigate the dependence of the common NMR parameters such as chemical shifts and relaxation times of several different nuclei and compounds on the pore structure of model microporous solids, carbons, and coals. In particular, we will study the interaction between several small molecules and the pore surfaces in coals. These molecules have been selected for their chemical and physical properties. A special NMR probe will be constructed which will allow the concurrent measurement of NMR properties and adsorption uptake at a variety of temperatures. All samples will be subjected to a suite of conventional'' pore structure analyses. These include nitrogen adsorption at 77 K with BET analysis, CO[sub 2] and CH[sub 4] adsorption at 273 K with D-R (Dubinin-Radushkevich) analysis, helium pycnometry, and small angle X-ray scattering as well as gas diffusion measurements.

  9. Polymer Molecular Weight Analysis by [Superscript 1]H NMR Spectroscopy

    ERIC Educational Resources Information Center

    Izunobi, Josephat U.; Higginbotham, Clement L.

    2011-01-01

    The measurement and analysis of molecular weight and molecular weight distribution remain matters of fundamental importance for the characterization and physical properties of polymers. Gel permeation chromatography (GPC) is the most routinely used method for the molecular weight determination of polymers whereas matrix-assisted laser…

  10. Glycerol and glycerol carbonate as ultraviscous solvents for mixture analysis by NMR

    NASA Astrophysics Data System (ADS)

    Lameiras, Pedro; Boudesocque, Leslie; Mouloungui, Zéphirin; Renault, Jean-Hugues; Wieruszeski, Jean-Michel; Lippens, Guy; Nuzillard, Jean-Marc

    2011-09-01

    NMR of weakly polar analytes in an apolar ultraviscous solvent has recently been proposed for mixture analysis as a pertinent alternative to the DOSY experiment. The present article reports the first use of glycerol and glycerol carbonate as polar solvents for the NMR analysis of a model mixture of dipeptides. This work demonstrates the high potentiality of these solvents for the analysis of mixtures made of polar and potentially bioactive compounds. Medium-sized molecules slowly reorient in glycerol and glycerol carbonate under particular temperature conditions, so that solute resonances may show spin diffusion in NOESY spectra, thus opening the way to mixture analysis. Glycerol and glycerol carbonate have turned out to be ultraviscous solvents of choice for the individualization of four structurally close mixed dipeptides: Leu-Val, Leu-Tyr, Gly-Tyr and Ala-Tyr by means of 1D and 2D NOESY experiments. Selective sample excitation and signal detection were implemented to eliminate the intense proton signals of the non-deuterated solvents. Moreover, the recording of a multiplet selective 2D NOESY-TOCSY has shown that the analytical power of NMR in highly viscous solvents is not limited to the extraction of mixture component 1D subspectra but may also yield some supplementary information about atom connectivity within components.

  11. In situ analysis of copper electrodeposition reaction using unilateral NMR sensor.

    PubMed

    Gomes, B F; Nunes, L M S; Lobo, C M S; Carvalho, A S; Cabeça, L F; Colnago, L A

    2015-12-01

    The uses of high-resolution NMR spectroscopy and imaging (MRI) to study electrochemical reactions in situ have greatly increased in the last decade. However, most of these applications are limited to specialized NMR laboratories and not feasible for routine analysis. Recently we have shown that a bench top, time domain NMR spectrometer can be used to monitor in situ copper electrodeposition reaction and the effect of Lorentz force in the reaction rate. However these spectrometers limit the cell size to the magnet gap and cannot be used with standard electrochemical cells. In this paper we are demonstrating that unilateral NMR sensor (UNMR), which does not limit sample size/volume, can be used to monitor electrodeposition of paramagnetic ions in situ. The copper electrodeposition reaction was monitored remotely and in situ, placing the electrochemical cell on top of the UNMR sensor. The Cu(2+) concentration was measured during three hours of the electrodeposition reactions, by using the transverse relaxation rate (R2) determined with the Carr-Purcell-Meiboom-Gill pulse sequence. The reaction rate increased fourfold when the reaction was performed in the presence of a magnetic field (in situ), in comparison to the reactions in the absence of the magnetic field (ex situ). The increase of reaction rate, in the presence of the UNMR magnet, was related to the magneto hydrodynamic force (FB) and magnetic field gradient force (F∇B). F∇B was calculated to be one order of magnitude stronger than FB. The UNMR sensor has several advantages for in situ measurements when compared to standard NMR spectrometers. It is a low cost, portable, open system, which does not limit sample size/volume and can be easily be adapted to standard electrochemical cells or large industrial reactors.

  12. In situ analysis of copper electrodeposition reaction using unilateral NMR sensor

    NASA Astrophysics Data System (ADS)

    Gomes, B. F.; Nunes, L. M. S.; Lobo, C. M. S.; Carvalho, A. S.; Cabeça, L. F.; Colnago, L. A.

    2015-12-01

    The uses of high-resolution NMR spectroscopy and imaging (MRI) to study electrochemical reactions in situ have greatly increased in the last decade. However, most of these applications are limited to specialized NMR laboratories and not feasible for routine analysis. Recently we have shown that a bench top, time domain NMR spectrometer can be used to monitor in situ copper electrodeposition reaction and the effect of Lorentz force in the reaction rate. However these spectrometers limit the cell size to the magnet gap and cannot be used with standard electrochemical cells. In this paper we are demonstrating that unilateral NMR sensor (UNMR), which does not limit sample size/volume, can be used to monitor electrodeposition of paramagnetic ions in situ. The copper electrodeposition reaction was monitored remotely and in situ, placing the electrochemical cell on top of the UNMR sensor. The Cu2+ concentration was measured during three hours of the electrodeposition reactions, by using the transverse relaxation rate (R2) determined with the Carr-Purcell-Meiboom-Gill pulse sequence. The reaction rate increased fourfold when the reaction was performed in the presence of a magnetic field (in situ), in comparison to the reactions in the absence of the magnetic field (ex situ). The increase of reaction rate, in the presence of the UNMR magnet, was related to the magneto hydrodynamic force (FB) and magnetic field gradient force (F∇B). F∇B was calculated to be one order of magnitude stronger than FB. The UNMR sensor has several advantages for in situ measurements when compared to standard NMR spectrometers. It is a low cost, portable, open system, which does not limit sample size/volume and can be easily be adapted to standard electrochemical cells or large industrial reactors.

  13. Characterization of phosphorus forms in lake macrophytes and algae by solution (31)P nuclear magnetic resonance spectroscopy.

    PubMed

    Feng, Weiying; Zhu, Yuanrong; Wu, Fengchang; Meng, Wei; Giesy, John P; He, Zhongqi; Song, Lirong; Fan, Mingle

    2016-04-01

    Debris from aquatic macrophytes and algae are important recycling sources of phosphorus (P), which can result in continuing blooms of algae by recycling bioavailable P in the eutrophic lakes. However, knowledge of forms of P in aquatic macrophytes and algae and their contribution to internal loads of P in lakes is limited. Without such knowledge, it is difficult to develop appropriate strategies to remediate and or restore aquatic ecosystems that have become eutrophic. Therefore, in this work, P was extracted from six types of aquatic macrophytes and algae collected from Tai Lake of China and characterized by use of solution (31)P-nuclear magnetic resonance (NMR) spectroscopy. When extracted by 0.5 M NaOH-25 mM EDTA, extraction recovery of total P(TP) and organic P(Po) exceeded 90 %. Concentrations of Po in algae and aquatic macrophytes were 5552 mg kg(-1) and 1005 mg kg(-1) and accounted for 56.0 and 47.2 % of TP, respectively. When Po, including condensed P, was characterized by solution (31)P-NMR Po in algae included orthophosphate monoesters (79.8 %), pyrophosphate (18.2 %), and orthophosphate diester (2.0 %), and Po in aquatic macrophytes included orthophosphate monoesters (90.3 %), pyrophosphate (4.2 %), and orthophosphate diester (5.5 %). Additionally, orthophosphate monoesters in algal debris mainly included β-glycerophosphate (44.1 %), α-glycerophosphate (13.5 %), and glucose 6-phosphate (13.5 %). Orthophosphate monoesters in aquatic macrophytes mainly included β-glycerophosphate (27.9 %), α-glycerophosphate (24.6 %), and adenosine 5' monophosphate (8.2 %). Results derived from this study will be useful in better understanding nutrient cycling, relevant eutrophication processes, and pollution control for freshwater lakes.

  14. NMR studies of a bacterial cell culture medium (LB broth): cyclic nucleotides in yeast extracts.

    PubMed

    Rayner, M H; Sadler, P J; Scawen, M D

    1990-03-01

    The composition of LB broth (tryptone, yeast extract and NaCl) was investigated by 1H,31P-NMR spectroscopy, FPLC and gel electrophoresis. An unexpected finding was the high level of 2'3'-cyclic nucleotides, detected by characteristic 31P-NMR resonances in the region 20-21 ppm, originating from the yeast component. 31P-NMR resonances for cyclic nucleotides were observed during the autolysis of Saccharomyces cerevisiae cells, and in model reactions of RNase with RNA.

  15. NMR metabolomic analysis of fecal water from subjects on a vegetarian diet.

    PubMed

    Pettersson, Jenny; Karlsson, Pernilla Christina; Choi, Young Hae; Verpoorte, Robert; Rafter, Joseph James; Bohlin, Lars

    2008-06-01

    A vegetarian diet rich in phytochemicals may prevent colon carcinogenesis by affecting biochemical processes in the colonic mucosa. Compounds passing the digestive system reaching the colon could potentially be detected in fecal water. We previously reported that intact fecal water samples from human volunteers significantly decreased prostaglandin production and COX-2 protein expression in colonic cells. The aim with the present study was to further study the composition of the fecal waters, using NMR spectroscopy and multivariate data analysis, and to trace the COX-2 inhibiting activity. Intact fecal water samples and fractions thereof were analyzed for their ability to inhibit prostaglandin E2 production in the human colon cell line HT-29. The majority of the tested aqueous phases derived from intact fecal water showed ability to inhibit prostaglandin production in cells (13.8+/-1.34% inhibition, p=0.01). NMR analysis indicated the presence of significant quantities of amino acids and fatty acids. Major metabolites included; acetic acid, butanoic acid, propanoic acid, glutamic acid and alanine. Smaller amounts of glycine and fumaric acid, which are known to have anti-inflammatory and anti-tumorigenic properties, were also detected. This study describes for the first time NMR metabolomic analysis of fecal water from subjects on a vegetarian diet.

  16. Chemical tagging of chlorinated phenols for their facile detection and analysis by NMR spectroscopy

    SciTech Connect

    Valdez, Carlos A.; Leif, Roald N.

    2015-03-22

    A derivatization method that employs diethyl (bromodifluoromethyl) phosphonate (DBDFP) to efficiently tag the endocrine disruptor pentachlorophenol (PCP) and other chlorinated phenols (CPs) along with their reliable detection and analysis by NMR is presented. The method accomplishes the efficient alkylation of the hydroxyl group in CPs with the difluoromethyl (CF2H) moiety in extremely rapid fashion (5 min), at room temperature and in an environmentally benign manner. The approach proved successful in difluoromethylating a panel of 18 chlorinated phenols, yielding derivatives that displayed unique 1H, 19F NMR spectra allowing for the clear discrimination between isomerically related CPs. Due to its biphasic nature, the derivatization can be applied to both aqueous and organic mixtures where the analysis of CPs is required. Furthermore, the methodology demonstrates that PCP along with other CPs can be selectively derivatized in the presence of other various aliphatic alcohols, underscoring the superiority of the approach over other general derivatization methods that indiscriminately modify all analytes in a given sample. The present work demonstrates the first application of NMR on the qualitative analysis of these highly toxic and environmentally persistent species.

  17. Strategy for choosing extraction procedures for NMR-based metabolomic analysis of mammalian cells.

    PubMed

    Martineau, Estelle; Tea, Illa; Loaëc, Gregory; Giraudeau, Patrick; Akoka, Serge

    2011-10-01

    Metabolomic analysis of mammalian cells can be applied across multiple fields including medicine and toxicology. It requires the acquisition of reproducible, robust, reliable, and homogeneous biological data sets. Particular attention must be paid to the efficiency and reliability of the extraction procedure. Even though a number of recent studies have dealt with optimizing a particular protocol for specific matrices and analytical techniques, there is no universal method to allow the detection of the entire cellular metabolome. Here, we present a strategy for choosing extraction procedures from adherent mammalian cells for the global NMR analysis of the metabolome. After the quenching of cells, intracellular metabolites are extracted from the cells using one of the following solvent systems of varying polarities: perchloric acid, acetonitrile/water, methanol, methanol/water, and methanol/chloroform/water. The hydrophilic metabolite profiles are analysed using (1)H nuclear magnetic resonance (NMR) spectroscopy. We propose an original geometric representation of metabolites reflecting the efficiency of extraction methods. In the case of NMR-based analysis of mammalian cells, this methodology demonstrates that a higher portion of intracellular metabolites are extracted by using methanol or methanol/chloroform/water. The preferred method is evaluated in terms of biological variability for studying metabolic changes caused by the phenotype of four different human breast cancer cell lines, showing that the selected extraction procedure is a promising tool for metabolomic and metabonomic studies of mammalian cells. The strategy proposed in this paper to compare extraction procedures is applicable to NMR-based metabolomic studies of various systems.

  18. Understanding the NMR properties and conformational behavior of indole vs. azaindole group in protoberberines: NICS and NCS analysis

    NASA Astrophysics Data System (ADS)

    Kadam, Shivaji S.; Toušek, Jaromír; Maier, Lukáš; Pipíška, Matej; Sklenář, Vladimír; Marek, Radek

    2012-11-01

    We report here the preparation and the structural investigation into a series of 8-(indol-1-yl)-7,8-dihydroprotoberberine derivatives derived from berberine, palmatine, and coptisine. Structures of these new compounds were characterized mainly by 2D NMR spectroscopy and the conformational behavior was investigated by using methods of density-functional theory (DFT). PBE0/6-311+G** calculated NMR chemical shifts for selected derivatives correlate excellently with the experimental NMR data and support the structural conclusions drawn from the NMR experiments. An interesting role of the nitrogen atom in position N7' of the indole moiety in 8-(7-azaindol-1-yl)-7,8-dihydroprotoberberines as compared to other 8-indolyl derivatives is investigated in detail. The experimentally observed trends in NMR chemical shifts are rationalized by DFT calculations and analysis based on the nucleus-independent chemical shifts (NICS) and natural localized molecular orbitals (NLMOs).

  19. TCA Cycle Turnover And Serum Glucose Sources By Automated Bayesian Analysis Of NMR Spectra

    SciTech Connect

    Merritt, Matthew E.; Burgess, Shawn; Jeffrey, F. Mark; Sherry, A. Dean; Malloy, Craig; Bretthorst, G. Larry

    2004-04-21

    Changes in sources of serum glucose are indicative of a variety of pathological metabolic states. It is possible to measure the sources of serum glucose by the administration of deuterated water to a subject followed by analysis of the 2H enrichment levels in glucose extracted from plasma from a single blood draw by 2H NMR. Markov Chain Monte Carlo simulations of the posterior probability densities may then be used to evaluate the contribution of glycogenolysis, glycerol, and the Kreb's cycle to serum glucose. Experiments with simulated NMR spectra show that in spectra with a S/N of 20 to 1, the resulting metabolic information may be evaluated with an accuracy of about 4 percent.

  20. Field-induced periodic distortions in a nematic liquid crystal: deuterium NMR study and theoretical analysis.

    PubMed

    Sugimura, A; Zakharov, A V

    2011-08-01

    The peculiarities in the dynamic of the director reorientation in a liquid crystal (LC) film under the influence of the electric E field directed at an angle α to the magnetic B field have been investigated both experimentally and theoretically. Time-resolved deuterium NMR spectroscopy is employed to investigate the field-induced director dynamics. Analysis of the experimental results, based on the predictions of hydrodynamic theory including both the director motion and fluid flow, provides an evidence for the appearance of the spatially periodic patterns in 4-n-pentyl-4'-cyanobiphenyl LC film, at the angles α>60∘, in response to the suddenly applied E. These periodic distortions produce a lower effective rotational viscosity. This gives a faster response of the director rotation than for a uniform mode, as observed in our NMR experiment. PMID:21929001

  1. Phenyl galactopyranosides - 13C CPMAS NMR and conformational analysis using genetic algorithm

    NASA Astrophysics Data System (ADS)

    Wałejko, Piotr; Paradowska, Katarzyna; Bukowicki, Jarosław; Witkowski, Stanisław; Wawer, Iwona

    2015-08-01

    Structural analyses of four compounds (phenyl 2,3,4,6-tetra-O-acetyl-β-D-galactopyranoside (1), phenyl β-D-galactopyranoside (2), phenyl 2,3,4,6-tetra-O-acetyl-α-D-galactopyranoside (3) and phenyl α-D-galactopyranoside (4)) have been performed using solid-state 13C MAS NMR spectroscopy and theoretical methods. Conformational analysis involved grid search and genetic algorithm (GAAGS). Low-energy conformers found by GAAGS were further optimized by DFT and chemical shifts were calculated using GIAO/DFT approach. 13C CPMAS NMR chemical shift of carbon C2 is indicative of the glycoside torsional angle. Separated or merged resonances of C2 and C6 suggest free rotation of phenyl ring in the solid phase.

  2. TCA Cycle Turnover And Serum Glucose Sources By Automated Bayesian Analysis Of NMR Spectra

    NASA Astrophysics Data System (ADS)

    Merritt, Matthew E.; Burgess, Shawn; Jeffrey, F. Mark; Sherry, A. Dean; Malloy, Craig; Bretthorst, G. Larry

    2004-04-01

    Changes in sources of serum glucose are indicative of a variety of pathological metabolic states. It is possible to measure the sources of serum glucose by the administration of deuterated water to a subject followed by analysis of the 2H enrichment levels in glucose extracted from plasma from a single blood draw by 2H NMR. Markov Chain Monte Carlo simulations of the posterior probability densities may then be used to evaluate the contribution of glycogenolysis, glycerol, and the Kreb's cycle to serum glucose. Experiments with simulated NMR spectra show that in spectra with a S/N of 20 to 1, the resulting metabolic information may be evaluated with an accuracy of about 4 percent.

  3. NMR bioreactor development for live in-situ microbial functional analysis

    NASA Astrophysics Data System (ADS)

    Majors, Paul D.; McLean, Jeffrey S.; Scholten, Johannes C. M.

    2008-05-01

    A live, in-situ metabolomics capability was developed for prokaryotic cultures under controlled growth conditions. Toward this goal, a radiofrequency-transparent bioreactor was developed and integrated with a commercial wide-bore nuclear magnetic resonance (NMR) imaging spectrometer and a commercial bioreactor controller. Water suppressed 1H NMR spectroscopy was used to monitor glucose and fructose utilization and byproduct excretion by Eubacterium aggregans (an anaerobic bacterial species relevant for biofuel production) under controlled batch and continuous culture conditions. The resulting metabolite profiles (short chain organic acids and ethanol) and trends are consistent with existing knowledge of its metabolism. However, our study also showed that E. aggregans produces lactate end product in significant concentrations—a result not previously reported. The advantages of live in-situ microbial metabolomics analysis and its complementariness with functional genomics/systems biology methods are discussed.

  4. NMR bioreactor development for live in-situ microbial functional analysis

    SciTech Connect

    Majors, Paul D.; Mclean, Jeffrey S.; Scholten, Johannes C.

    2008-05-01

    A live in-situ metabolomics capability was developed for prokaryotic cultures under controlled-growth conditions. Toward this goal, a radiofrequency-transparent bioreactor was developed and integrated with a commercial wide-bore nuclear magnetic resonance (NMR) imaging spectrometer and a commercial bioreactor controller. Water suppressed 1H NMR spectroscopy was used to monitor glucose and fructose utilization and byproduct excretion by Eubacterium aggregans (an anaerobic bacterial species relevant for biofuels production) under controlled batch and continuous culture conditions. The resulting metabolite profiles (short chain organic acids and ethanol) and trends are consistent with existing knowledge of its metabolism. However, our study showed the Eubacterium aggregans produces lactate end product in significant concentrations – a result not previously reported. The advantages of live in-situ microbial metabolomics analysis and its complementariness with functional genomics / systems biology methods are discussed.

  5. Analysis of the extracts of Isatis tinctoria by new analytical approaches of HPLC, MS and NMR.

    PubMed

    Zhou, Jue; Qu, Fan

    2011-01-01

    The methods of extraction, separation and analysis of alkaloids and indole glucosinolates (GLs) ofIsatis tinctoria were reviewed. Different analytical approaches such as High-pressure Liquid Chromatography (HPLC), Liquid Chromatography with Electrospray Ionization Mass Spectrometry (LC/ESI/MS), Electrospray Ionization Time-Of-Flight Mass Spectrometry (ESI-TOF-MS), and Nuclear Magnetic Resonance (NMR) were used to validate and identity of these constituents. These methods provide rapid separation, identification and quantitative measurements of alkaloids and GLs of Isatis tinctoria. By connection with different detectors to HPLC such as PDA, ELSD, ESI- and APCI-MS in positive and negative ion modes, complicated compounds could be detected with at least two independent detection modes. The molecular formula can be derived in a second step of ESI-TOF-MS data. But for some constituents, UV and MS cannot provide sufficient structure identification. After peak purification, NMR by semi-preparative HPLC can be used as a complementary method.

  6. Development of an 19F NMR method for the analysis of fluorinated acids in environmental water samples.

    PubMed

    Ellis, D A; Martin, J W; Muir, D C; Mabury, S A

    2000-02-15

    This investigation was carried out to evaluate 19F NMR as an analytical tool for the measurement of trifluoroacetic acid (TFA) and other fluorinated acids in the aquatic environment. A method based upon strong anionic exchange (SAX) chromatography was also optimized for the concentration of the fluoro acids prior to NMR analysis. Extraction of the analyte from the SAX column was carried out directly in the NMR solvent in the presence of the strong organic base, DBU. The method allowed the analysis of the acid without any prior cleanup steps being involved. Optimal NMR sensitivity based upon T1 relaxation times was investigated for seven fluorinated compounds in four different NMR solvents. The use of the relaxation agent chromium acetylacetonate, Cr(acac)3, within these solvent systems was also evaluated. Results show that the optimal NMR solvent differs for each fluorinated analyte. Cr(acac)3 was shown to have pronounced effects on the limits of detection of the analyte. Generally, the optimal sensitivity condition appears to be methanol-d4/2M DBU in the presence of 4 mg/mL of Cr-(acac)3. The method was validated through spike and recovery for five fluoro acids from environmentally relevant waters. Results are presented for the analysis of TFA in Toronto rainwater, which ranged from < 16 to 850 ng/L. The NMR results were confirmed by GC-MS selected-ion monitoring of the fluoroanalide derivative.

  7. GUARDD: user-friendly MATLAB software for rigorous analysis of CPMG RD NMR data.

    PubMed

    Kleckner, Ian R; Foster, Mark P

    2012-01-01

    Molecular dynamics are essential for life, and nuclear magnetic resonance (NMR) spectroscopy has been used extensively to characterize these phenomena since the 1950s. For the past 15 years, the Carr-Purcell Meiboom-Gill relaxation dispersion (CPMG RD) NMR experiment has afforded advanced NMR labs access to kinetic, thermodynamic, and structural details of protein and RNA dynamics in the crucial μs-ms time window. However, analysis of RD data is challenging because datasets are often large and require many non-linear fitting parameters, thereby confounding assessment of accuracy. Moreover, novice CPMG experimentalists face an additional barrier because current software options lack an intuitive user interface and extensive documentation. Hence, we present the open-source software package GUARDD (Graphical User-friendly Analysis of Relaxation Dispersion Data), which is designed to organize, automate, and enhance the analytical procedures which operate on CPMG RD data ( http://code.google.com/p/guardd/). This MATLAB-based program includes a graphical user interface, permits global fitting to multi-field, multi-temperature, multi-coherence data, and implements χ (2)-mapping procedures, via grid-search and Monte Carlo methods, to enhance and assess fitting accuracy. The presentation features allow users to seamlessly traverse the large amount of results, and the RD Simulator feature can help design future experiments as well as serve as a teaching tool for those unfamiliar with RD phenomena. Based on these innovative features, we expect that GUARDD will fill a well-defined gap in service of the RD NMR community.

  8. New direct 11B NMR-based analysis of organoboranes through their potassium borohydrides.

    PubMed

    Medina, Jesus R; Cruz, Gabriel; Cabrera, Carlos R; Soderquist, John A

    2003-06-13

    Representative organoborane mixtures were quantitatively converted to their borohydrides through their reaction with activated KH (KH), permitting their detailed analysis by (11)B NMR. Through the treatment of commercial KH with a THF solution of lithium aluminum hydride (LAH), a dramatic change in the surface morphology results as revealed by scanning electron microscopy (SEM). Energy dispersed spectroscopy (EDS) was employed to reveal that the LAH treatment deposits a significant amount of an unknown aluminum-containing species on the surface of the KH, which imparts a unique reactivity to the KH. Even highly hindered organoboranes are quantitatively converted to their borohydrides by replacing electronegative groups (e.g., OR, halogen) with hydrogen, retaining only the carbon ligation. Through this simple KH treatment, complex organoborane reaction mixtures are converted to the corresponding borohydrides whose (11)B NMR spectra normally exhibit resolved signals for the individual species present. The integration of these signals provides quantitative information on the relative amounts of each component of the mixture. New generalities for the effect of alpha-, beta-, and gamma-substituents have also been determined that provide a new, simple technique for the determination of the isomeric distribution in organoborane mixtures resulting from common organoborane processes (e.g., hydroboration). Moreover, the (1)H-coupled (11)B NMR spectra of these mixtures reveal the extent of alkylation for each species present. Representative organoboranes were examined by this new technique permitting a simple and convenient quantitative analysis of the regio- and diastereomeric composition of a variety of asymmetric organoborane processes. Previously unknown details of pinene-based hydroborations and reductions are revealed for the first time employing the KH (11)B NMR technique. PMID:12790565

  9. MQ NMR and SPME analysis of nonlinearity in the degradation of a filled silicone elastomer.

    PubMed

    Chinn, Sarah C; Alviso, Cynthia T; Berman, Elena S F; Harvey, Christopher A; Maxwell, Robert S; Wilson, Thomas S; Cohenour, Rebecca; Saalwächter, Kay; Chassé, Walter

    2010-08-01

    Radiation-induced degradation of polymeric materials occurs through numerous, simultaneous, competing chemical reactions. Although degradation is typically found to be linear in adsorbed dose, some silicone materials exhibit nonlinear dose dependence due to dose-dependent dominant degradation pathways. We have characterized the effects of radiative and thermal degradation on a model filled-PDMS system, Sylgard 184 (commonly used in electronic encapsulation and in biomedical applications), using traditional mechanical testing, NMR spectroscopy, and sample headspace analysis using solid-phase microextraction (SPME) followed by gas chromatography/mass spectrometry (GC/MS). The mechanical data and (1)H spin-echo NMR spectra indicated that radiation exposure leads to predominantly cross-linking over the cumulative dose range studied (0-250 kGy) with a rate roughly linear with dose. (1)H multiple-quantum NMR spectroscopy detected a bimodal distribution in the network structure, as expected from the proposed structure of Sylgard 184. The MQ NMR spectra further indicated that the radiation-induced structural changes were not linear in adsorbed dose and that competing chain scission mechanisms made a greater contribution to the overall degradation process in the range of 50-100 kGy (although cross-linking still dominated). The SPME-GC/MS data were analyzed using principal component analysis (PCA), which identified subtle changes in the distributions of degradation products (the cyclic siloxanes and other components of the material) as a function of age that provide insight into the dominant degradation pathways at low and high adsorbed dose.

  10. NMR methods in combinatorial chemistry.

    PubMed

    Shapiro, M J; Wareing, J R

    1998-06-01

    The use of NMR spectroscopy in combinatorial chemistry has provided a versatile tool for monitoring combinatorial chemistry reactions and for assessing ligand-receptor interactions. The application of magic angle spinning NMR is widespread and has allowed structure determination to be performed on compounds attached to solid supports. A variety of two-dimensional NMR techniques have been applied to enhance the usability of the magic angle spinning NMR data. New developments for solution NMR analysis include high performance liquid chromatography, NMR, mass spectroscopy and flow NMR. NMR based methods currently being investigated may prove valuable as compound screening tools.

  11. Comparison of phytate and other organic P forms in Mehlich-3 and Alkaline-EDTA matrices by ICP, NMR and mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The favored method of organic P identification over the last few decades has been 31P NMR. While this technique has the distinct advantage of speciating the organic P fraction, it has a relatively poor detection threshold (0.05 mg/ml), which typically limits 31P NMR to qualitative or confirmative ap...

  12. 31P nuclear magnetic resonance in vivo spectroscopy of the metabolic changes induced in the awake rat brain during KCN intoxication and its reversal by hydroxocobalamine.

    PubMed

    Benabid, A L; Decorps, M; Remy, C; Le Bas, J F; Confort, S; Leviel, J L

    1987-03-01

    Radiofrequency surface coils were chronically implanted in rats, which were subsequently subjected to 31P nuclear magnetic resonance (NMR) investigations at 4.7 T. The implanted coil allowed study of the animals without need for anesthesia, which is a prerequisite for studies of normal brain metabolism. The animals may be kept in the NMR probe for several hours. During subsequent experiments, they may be placed in the same position, therefore allowing follow-up studies for periods as long as 2 months. This method has been used in the study of sublethal KCN intoxication. KCN, a cytochrome c oxidase inhibitor, induces a blockade of cell respiratory processes, which is reflected, in a dose-dependent manner, by a decrease in phosphocreatine content and pH and an increase in inorganic phosphate content, whereas ATP levels remain constant until high doses of KCN (6 mg/kg i.p.) are reached. 31P NMR allows the time course of these metabolic changes to be followed. For high KCN doses, a new peak, termed X, is observed, which is interpreted as being due to a pool of inorganic phosphate at very low pH (5.65), corresponding to a subset of cells that did not survive KCN injury. Hydroxocobalamine, a specific antidote of KCN, suppresses the metabolic changes due to 6 mg/kg of KCN.

  13. 31P nuclear magnetic resonance in vivo spectroscopy of the metabolic changes induced in the awake rat brain during KCN intoxication and its reversal by hydroxocobalamine.

    PubMed

    Benabid, A L; Decorps, M; Remy, C; Le Bas, J F; Confort, S; Leviel, J L

    1987-03-01

    Radiofrequency surface coils were chronically implanted in rats, which were subsequently subjected to 31P nuclear magnetic resonance (NMR) investigations at 4.7 T. The implanted coil allowed study of the animals without need for anesthesia, which is a prerequisite for studies of normal brain metabolism. The animals may be kept in the NMR probe for several hours. During subsequent experiments, they may be placed in the same position, therefore allowing follow-up studies for periods as long as 2 months. This method has been used in the study of sublethal KCN intoxication. KCN, a cytochrome c oxidase inhibitor, induces a blockade of cell respiratory processes, which is reflected, in a dose-dependent manner, by a decrease in phosphocreatine content and pH and an increase in inorganic phosphate content, whereas ATP levels remain constant until high doses of KCN (6 mg/kg i.p.) are reached. 31P NMR allows the time course of these metabolic changes to be followed. For high KCN doses, a new peak, termed X, is observed, which is interpreted as being due to a pool of inorganic phosphate at very low pH (5.65), corresponding to a subset of cells that did not survive KCN injury. Hydroxocobalamine, a specific antidote of KCN, suppresses the metabolic changes due to 6 mg/kg of KCN. PMID:3027259

  14. Filtering and parameter estimation of surface-NMR data using singular spectrum analysis

    NASA Astrophysics Data System (ADS)

    Ghanati, Reza; Kazem Hafizi, Mohammad; Mahmoudvand, Rahim; Fallahsafari, Mahdi

    2016-07-01

    Ambient electromagnetic interferences at the site of investigation often degrade the signal quality of the Surface-NMR measurements leading to inaccurate estimation of the signal parameters. This paper proposes a new powerful de-noising method based on singular spectrum analysis (SSA), which is a nonparametric method for analyzing time series. SSA is a relatively simple method and can be understood using basic algebra notations. Singular value decomposition (SVD) plays a crucial role in SSA. As the length of recordings increases, the computational time required for computing SVD raises which restricts the usage of SSA in long-term time series. In order to overcome this drawback, we propose a randomized version of the singular value decomposition to accelerate the decomposition step of the algorithm. To evaluate the performance of the proposed strategy, the method is tested on synthetic signals corrupted by both simulated noise (including Gaussian white noise, spiky events and harmonic noise) and real noise recordings obtained from surface-NMR field surveys and a real data set. Our results show that the proposed algorithm can enhance the signal to noise ratio significantly, and gives an improvement in estimation of the surface-NMR signal parameters.

  15. Fractional order analysis of Sephadex gel structures: NMR measurements reflecting anomalous diffusion

    NASA Astrophysics Data System (ADS)

    Magin, Richard L.; Akpa, Belinda S.; Neuberger, Thomas; Webb, Andrew G.

    2011-12-01

    We report the appearance of anomalous water diffusion in hydrophilic Sephadex gels observed using pulse field gradient (PFG) nuclear magnetic resonance (NMR). The NMR diffusion data was collected using a Varian 14.1 Tesla imaging system with a home-built RF saddle coil. A fractional order analysis of the data was used to characterize heterogeneity in the gels for the dynamics of water diffusion in this restricted environment. Several recent studies of anomalous diffusion have used the stretched exponential function to model the decay of the NMR signal, i.e., exp[-( bD) α], where D is the apparent diffusion constant, b is determined the experimental conditions (gradient pulse separation, durations and strength), and α is a measure of structural complexity. In this work, we consider a different case where the spatial Laplacian in the Bloch-Torrey equation is generalized to a fractional order model of diffusivity via a complexity parameter, β, a space constant, μ, and a diffusion coefficient, D. This treatment reverts to the classical result for the integer order case. The fractional order decay model was fit to the diffusion-weighted signal attenuation for a range of b-values (0 < b < 4000 s mm -2). Throughout this range of b values, the parameters β, μ and D, were found to correlate with the porosity and tortuosity of the gel structure.

  16. 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.

  17. A new approach to quantitative NMR: fluoroquinolones analysis by evaluating the chemical shift displacements.

    PubMed

    Michaleas, S; Antoniadou-Vyza, E

    2006-10-11

    Quantitative NMR spectroscopy is always an attractive goal as the identity and quantity could be simultaneously determined. Although significant advancements have been achieved in this field it is common that all reported quantitative NMR methods perform the analysis by utilizing the average integral intensities of selected signals. During the calculation of the area under NMR peaks several response problems can occur which should always be treated carefully to overcome inaccuracies. In the method proposed in this work the quantitative information is obtained utilizing the measurement of selected protons chemical shift displacements which is a quite straightforward and highly reproducible process. The (1)H NMR spectra of multiple fluoroquinolone (FQ) solutions revealed that the chemical shifts of protons, especially the aromatic ones, were concentration dependent for all tested compounds, as a result of extensive self-association phenomena. In the present work a novel methodology is described for the quantitation of several FQs based on this dependence. The proposed method was applied to Ciprofloxacin solutions over a wide range of concentrations. Evaluation of the obtained data presented acceptable characteristics regarding accuracy, precision, and robustness. The applicability limitations of this method were found to be posed by current instrumentation, mainly by the magnetic field frequency e.g. the slope of the response function achieved with a 400MHz instrument was twice the one achieved at 200MHz. The pH effect was negligible from pD 2.5 to 5.5. The phenomenon appeared in a pattern that can be applied for a plethora of drug categories revealing self-association phenomena in a range of concentration determined by the magnet strength of the instrument.

  18. Bone mineral (31)P and matrix-bound water densities measured by solid-state (31)P and (1)H MRI.

    PubMed

    Seifert, Alan C; Li, Cheng; Rajapakse, Chamith S; Bashoor-Zadeh, Mahdieh; Bhagat, Yusuf A; Wright, Alexander C; Zemel, Babette S; Zavaliangos, Antonios; Wehrli, Felix W

    2014-07-01

    Bone is a composite material consisting of mineral and hydrated collagen fractions. MRI of bone is challenging because of extremely short transverse relaxation times, but solid-state imaging sequences exist that can acquire the short-lived signal from bone tissue. Previous work to quantify bone density via MRI used powerful experimental scanners. This work seeks to establish the feasibility of MRI-based measurement on clinical scanners of bone mineral and collagen-bound water densities, the latter as a surrogate of matrix density, and to examine the associations of these parameters with porosity and donors' age. Mineral and matrix-bound water images of reference phantoms and cortical bone from 16 human donors, aged 27-97 years, were acquired by zero-echo-time 31-phosphorus ((31)P) and 1-hydrogen ((1)H) MRI on whole body 7T and 3T scanners, respectively. Images were corrected for relaxation and RF inhomogeneity to obtain density maps. Cortical porosity was measured by micro-computed tomography (μCT), and apparent mineral density by peripheral quantitative CT (pQCT). MRI-derived densities were compared to X-ray-based measurements by least-squares regression. Mean bone mineral (31)P density was 6.74 ± 1.22 mol/l (corresponding to 1129 ± 204 mg/cc mineral), and mean bound water (1)H density was 31.3 ± 4.2 mol/l (corresponding to 28.3 ± 3.7 %v/v). Both (31)P and bound water (BW) densities were correlated negatively with porosity ((31)P: R(2) = 0.32, p < 0.005; BW: R(2) = 0.63, p < 0.0005) and age ((31)P: R(2) = 0.39, p < 0.05; BW: R(2) = 0.70, p < 0.0001), and positively with pQCT density ((31)P: R(2) = 0.46, p < 0.05; BW: R(2) = 0.50, p < 0.005). In contrast, the bone mineralization ratio (expressed here as the ratio of (31)P density to bound water density), which is proportional to true bone mineralization, was found to be uncorrelated with porosity, age or pQCT density. This work establishes the feasibility of image-based quantification of bone mineral and bound

  19. Characterization of the phosphoserine of pepsinogen using /sup 31/P nuclear magnetic resonance: corroboration of X-ray crystallographic results

    SciTech Connect

    Williams, S.P.; Bridger, W.A.; James, M.N.G.

    1986-10-21

    The endogenous phosphoserine residue in porcine pepsinogen has been titrated with use of phosphorus-31 nuclear magnetic resonance (/sup 31/P NMR). It has an observed pK/sub a/sub 2// of 6.7 and a narrow line width (approx. =10 Hz). The phosphate can be readily removed by an acid phosphatase from potato; however, it is resistant to hydrolysis by several alkaline phosphatases. The X-ray crystal structure of porcine pepsinogen at 1.8-A resolution shows a rather weak and diffuse region of electron density in the vicinity of the phosphorylated serine residue. This suggests considerable dynamic mobility or conformational disorder of the phosphate. In order to define more fully this behavior the NMR data have been used to corroborate these crystallographic results. All these physical data are consistent with a highly mobile phosphoserine residue on the surface of the zymogen and freely exposed to solvent. In addition, certain properties of this phosphoserine moiety on pepsinogen are similar to those of one of the phosphorylated residues of ovalbumin. The possible significance of this is discussed.

  20. Conformational analysis, tautomerization, IR, Raman, and NMR studies of ethyl benzoylacetate

    NASA Astrophysics Data System (ADS)

    Tayyari, Sayyed Faramarz; Chahkandi, Behzad; Mehrani, Sepideh; McClurg, Ryan W.; Keyes, Chad A.; Sammelson, Robert E.

    2012-05-01

    A complete conformational analysis of the keto and enol forms of ethyl benzoylacetate (EBA), a β-ketoester, was carried out by ab initio calculations, at the density functional theory (DFT) level. The relative stabilities of cis-enol and keto forms were calculated in the gas phase and in solution. The intramolecular hydrogen bond characters of the most stable enol forms of EBA are discussed and compared with those of benzoylacetone (BA). Harmonic vibrational frequencies and 1H and 13C NMR chemical shifts of the most stable enol and keto forms were also calculated at the B3LYP/6-311++G** level and compared with the experimental data.

  1. Tannin structural elucidation and quantitative ³¹P NMR analysis. 2. Hydrolyzable tannins and proanthocyanidins.

    PubMed

    Melone, Federica; Saladino, Raffaele; Lange, Heiko; Crestini, Claudia

    2013-10-01

    An unprecedented analytical method that allows simultaneous structural and quantitative characterization of all functional groups present in tannins is reported. In situ labeling of all labile H groups (aliphatic and phenolic hydroxyls and carboxylic acids) with a phosphorus-containing reagent (Cl-TMDP) followed by quantitative ³¹P NMR acquisition constitutes a novel fast and reliable analytical tool for the analysis of tannins and proanthocyanidins with significant implications for the fields of food and feed analyses, tannery, and the development of natural polyphenolics containing products. PMID:23998855

  2. DFT molecular modeling and NMR conformational analysis of a new longipinenetriolone diester

    NASA Astrophysics Data System (ADS)

    Cerda-García-Rojas, Carlos M.; Guerra-Ramírez, Diana; Román-Marín, Luisa U.; Hernández-Hernández, Juan D.; Joseph-Nathan, Pedro

    2006-05-01

    The structure and conformational behavior of the new natural compound (4 R,5 S,7 S,8 R,9 S,10 R,11 R)-longipin-2-en-7,8,9-triol-1-one 7-angelate-9-isovalerate (1) isolated from Stevia eupatoria, were studied by molecular modeling and NMR spectroscopy. A Monte Carlo search followed by DFT calculations at the B3LYP/6-31G* level provided the theoretical conformations of the sesquiterpene framework, which were in full agreement with results derived from the 1H- 1H coupling constant analysis.

  3. 31P-nuclear magnetic resonance spectroscopy in vivo of six human melanoma xenograft lines: tumour bioenergetic status and blood supply.

    PubMed Central

    Lyng, H.; Olsen, D. R.; Southon, T. E.; Rofstad, E. K.

    1993-01-01

    Six human melanoma xenograft lines grown s.c. in BALB/c-nu/nu mice were subjected to 31P-nuclear magnetic resonance (31P-NMR) spectroscopy in vivo. The following resonances were detected: phosphomonoesters (PME), inorganic phosphate (Pi), phosphodiesters (PDE), phosphocreatine (PCr) and nucleoside triphosphate gamma, alpha and beta (NTP gamma, alpha and beta). The main purpose of the work was to search for possible relationships between 31P-NMR resonance ratios and tumour pH on the one hand and blood supply per viable tumour cell on the other. The latter parameter was measured by using the 86Rb uptake method. Tumour bioenergetic status [the (PCr + NTP beta)/Pi resonance ratio], tumour pH and blood supply per viable tumour cell decreased with increasing tumour volume for five of the six xenograft lines. The decrease in tumour bioenergetic status was due to a decrease in the (PCr + NTP beta)/total resonance ratio as well as an increase in the Pi/total resonance ratio. The decrease in the (PCr + NTP beta)/total resonance ratio was mainly a consequence of a decrease in the PCr/total resonance ratio for two lines and mainly a consequence of a decrease in the NTP beta/total resonance ratio for three lines. The magnitude of the decrease in the (PCr + NTP beta)/total resonance ratio and the magnitude of the decrease in tumour pH were correlated to the magnitude of the decrease in blood supply per viable tumour cell. Tumour pH decreased with decreasing tumour bioenergetic status, and the magnitude of this decrease was larger for the tumour lines showing a high than for those showing a low blood supply per viable tumour cell. No correlations across the tumour lines were found between tumour pH and tumour bioenergetic status or any other resonance ratio on the one hand and blood supply per viable tumour cell on the other. The differences in the 31P-NMR spectrum between the tumour lines were probably caused by differences in the intrinsic biochemical properties of the tumour

  4. Quantitative analysis of polymer mixtures in solution by pulsed field-gradient spin echo NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Van Lokeren, Luk; Ben Sassi, Hanen; Van Assche, Guy; Ribot, François

    2013-06-01

    Pulsed Field-Gradient Spin Echo (PGSE) NMR, which associates to a spectral dimension the measure of diffusion coefficients, is a convenient technique for mixture analysis. Unfortunately, because of relaxation, the quantification of mixtures by PGSE NMR is far from straightforward for mixtures with strong spectral overlap. Antalek (J. Am. Chem. Soc. 128 (2006) 8402-8403) proposed a quantification strategy based on DECRA analysis and extrapolation to zero of the diffusion delay. More recently, Barrère et al. (J. Magn. Reson. 216 (2012) 201-208) presented a new strategy based also on DECRA and on the renormalization of the intensities using estimates of the T1 and T2 relaxation times. Here we report an alternative quantification approach in which the fractions are obtained by analyzing the PGSE attenuation profile with a general Stejskal-Tanner equation that explicitly includes the relaxation effects. The required values of T1 and T2 relaxation times are either independently measured with conventional sequences or determined, along with the fractions and the diffusion coefficients, from the simultaneous analysis of up to 6 PGSE data sets recorded with different diffusion delays. This method yields errors lower than 3% for the fractions, even for complete spectral overlap, as demonstrated on model binary and ternary mixtures of polystyrene in the case of a convection compensating double stimulated echo (DSTE) sequence.

  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. Quantitative analysis of polymer mixtures in solution by pulsed field-gradient spin echo NMR spectroscopy.

    PubMed

    Van Lokeren, Luk; Ben Sassi, Hanen; Van Assche, Guy; Ribot, François

    2013-06-01

    Pulsed Field-Gradient Spin Echo (PGSE) NMR, which associates to a spectral dimension the measure of diffusion coefficients, is a convenient technique for mixture analysis. Unfortunately, because of relaxation, the quantification of mixtures by PGSE NMR is far from straightforward for mixtures with strong spectral overlap. Antalek (J. Am. Chem. Soc. 128 (2006) 8402-8403) proposed a quantification strategy based on DECRA analysis and extrapolation to zero of the diffusion delay. More recently, Barrère et al. (J. Magn. Reson. 216 (2012) 201-208) presented a new strategy based also on DECRA and on the renormalization of the intensities using estimates of the T1 and T2 relaxation times. Here we report an alternative quantification approach in which the fractions are obtained by analyzing the PGSE attenuation profile with a general Stejskal-Tanner equation that explicitly includes the relaxation effects. The required values of T1 and T2 relaxation times are either independently measured with conventional sequences or determined, along with the fractions and the diffusion coefficients, from the simultaneous analysis of up to 6 PGSE data sets recorded with different diffusion delays. This method yields errors lower than 3% for the fractions, even for complete spectral overlap, as demonstrated on model binary and ternary mixtures of polystyrene in the case of a convection compensating double stimulated echo (DSTE) sequence.

  7. 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. PMID:26395416

  8. Evaluation of integration procedures for PNA analysis by C-13 NMR

    SciTech Connect

    Yamashita, G.T.; Saetre, R.; Somogyvari, A. )

    1989-04-01

    Carbon-13 NMR spectroscopy has become a useful tool in the analysis of crude oils and petroleum products. The determination of the relative percentages of paraffinic, naphthenic and aromatic carbon in crude oils and oil fractions by carbon-13 nuclear magnetic resonance spectroscopy has been shown to compare well with results from ASTM D2140 procedures. In the ASTM method, the PNA analysis is determined by the refractive index, the density and the molecular weight of the material. In carbon-13 NMR spectroscopy, the carbon types are observed directly and, under appropriate conditions, can be readily quantified. Aromatic carbon resonances are observed in the 110-170 ppm region of the 25-60 ppm region of the spectrum. The paraffinic carbon signals are seen as a band of overlapping resonances in the 0-25 ppm region and as sharp resonances in the 25-60 ppm region. The relative percentages of these three carbon types is calculated by the ratio of the area of the resonances for each carbon type over the total area, excluding the solvent and reference peak areas. To study the effects of the baseline subtraction and the baseline correction subroutines on the PNA results, a typical crude oil and its asphaltene fraction were selected as model compounds. Generally, asphaltene samples display poor sensitivity when analyzed by carbon-13 NMR, so this fraction was chosen to examine the abilities of the two subroutines under non-ideal conditions. As well, the effect of line broadening factors on the PNA results was studied. Line broadening will increase the signal to noise ratio, but also leads to a decrease in resolution.

  9. LC-NMR Technique in the Analysis of Phytosterols in Natural Extracts

    PubMed Central

    Horník, Štěpán; Sajfrtová, Marie; Sýkora, Jan; Březinová, Anna; Wimmer, Zdeněk

    2013-01-01

    The ability of LC-NMR to detect simultaneously free and conjugated phytosterols in natural extracts was tested. The advantages and disadvantages of a gradient HPLC-NMR method were compared to the fast composition screening using SEC-NMR method. Fractions of free and conjugated phytosterols were isolated and analyzed by isocratic HPLC-NMR methods. The results of qualitative and quantitative analyses were in a good agreement with the literature data. PMID:24455424

  10. On Neglecting Chemical Exchange Effects When Correcting in Vivo 31P MRS Data for Partial Saturation

    NASA Astrophysics Data System (ADS)

    Ouwerkerk, Ronald; Bottomley, Paul A.

    2001-02-01

    Signal acquisition in most MRS experiments requires a correction for partial saturation that is commonly based on a single exponential model for T1 that ignores effects of chemical exchange. We evaluated the errors in 31P MRS measurements introduced by this approximation in two-, three-, and four-site chemical exchange models under a range of flip-angles and pulse sequence repetition times (TR) that provide near-optimum signal-to-noise ratio (SNR). In two-site exchange, such as the creatine-kinase reaction involving phosphocreatine (PCr) and γ-ATP in human skeletal and cardiac muscle, errors in saturation factors were determined for the progressive saturation method and the dual-angle method of measuring T1. The analysis shows that these errors are negligible for the progressive saturation method if the observed T1 is derived from a three-parameter fit of the data. When T1 is measured with the dual-angle method, errors in saturation factors are less than 5% for all conceivable values of the chemical exchange rate and flip-angles that deliver useful SNR per unit time over the range T1/5 ≤ TR ≤ 2T1. Errors are also less than 5% for three- and four-site exchange when TR ≥ T1*/2, the so-called "intrinsic" T1's of the metabolites. The effect of changing metabolite concentrations and chemical exchange rates on observed T1's and saturation corrections was also examined with a three-site chemical exchange model involving ATP, PCr, and inorganic phosphate in skeletal muscle undergoing up to 95% PCr depletion. Although the observed T1's were dependent on metabolite concentrations, errors in saturation corrections for TR = 2 s could be kept within 5% for all exchanging metabolites using a simple interpolation of two dual-angle T1 measurements performed at the start and end of the experiment. Thus, the single-exponential model appears to be reasonably accurate for correcting 31P MRS data for partial saturation in the presence of chemical exchange. Even in systems where

  11. Structure determination and analysis of helix parameters in the DNA decamer d(CATGGCCATG)2 comparison of results from NMR and crystallography.

    PubMed

    Dornberger, U; Flemming, J; Fritzsche, H

    1998-12-18

    The solution structure of the DNA decamer (CATGGCCATG)2 has been determined by NMR spectroscopy and restrained molecular dynamic and distance geometry calculations. The restrainted data set includes interproton distances and torsion angles for the deoxyribose sugar ring which were obtained by nuclear Overhauser enhancement intensities and quantitative simulation of cross-peaks from double quantum filtered correlation spectroscopy. The backbone torsion angles were constrained using experimental data from NOE cross-peaks, 1H-1H and 1H-31P-coupling constants. The NMR structure and the crystal structure of the DNA decamer deviates from the structure of the canonical form of B-DNA in a number of observable characteristics. Particularly, both structures display a specific pattern of stacking interaction in the central GGC base triplet. Furthermore, a specific local conformation of the TG/CA base-pair step is present in NMR and crystal structure, highlighting the unusually high flexibility of this DNA duplex part. The solution structure of the TG/CA base-pair step obtained by our high resolution NMR study is characterized by a positive roll angle, whereas in crystal this base-pair step tends to adopt remarkably high twist angles.

  12. 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

  13. Advancement of 31P Magnetic Resonance Spectroscopy Using GRAPPA Reconstruction on a 3D Volume

    NASA Astrophysics Data System (ADS)

    Clevenger, Tony

    The overall objective of this research is to improve currently available metabolic imaging techniques for clinical use in monitoring and predicting treatment response to radiation therapy in liver cancer. Liver metabolism correlates with inflammatory and neoplastic liver diseases, which alter the intracellular concentration of phosphorus- 31 (31P) metabolites [1]. It is assumed that such metabolic changes occur prior to physical changes of the tissue. Therefore, information on regional changes of 31P metabolites in the liver, obtained by Magnetic Resonance Spectroscopic Imaging (MRSI) [1,2], can help in diagnosis and follow-up of various liver diseases. Specifically, there appears to be an immediate need of this technology for both the assessment of tumor response in patients with Hepatocellular Carcinoma (HCC) treated with Stereotactic Body Radiation Therapy (SBRT) [3--5], as well as assessment of radiation toxicity, which can result in worsening liver dysfunction [6]. Pilot data from our lab has shown that 31P MRSI has the potential to identify treatment response five months sooner than conventional methods [7], and to assess the biological response of liver tissue to radiation 24 hours post radiation therapy [8]. While this data is very promising, commonly occurring drawbacks for 31P MRSI are patient discomfort due to long scan times and prone positioning within the scanner, as well as reduced data quality due to patient motion and respiration. To further advance the full potential of 31P MRSI as a clinical diagnostic tool in the management of liver cancer, this PhD research project had the following aims: I) Reduce the long acquisition time of 3D 31P MRS by formulating and imple- menting an appropriate GRAPPA undersampling scheme and reconstruction on a clinical MRI scanner II) Testing and quantitative validation of GRAPPA reconstruction on 3D 31P MRSI on developmental phantoms and healthy volunteers At completion, this work should considerably advance 31P MRSI

  14. Effects of sleep deprivation on sleep homeostasis and restoration during methadone-maintenance: a [31] P MRS brain imaging study

    PubMed Central

    Trksak, George H.; Jensen, J. Eric; Plante, David T.; Penetar, David M.; Tartarini, Wendy L.; Maywalt, Melissa A.; Brendel, Michael; Dorsey, Cynthia M.; Renshaw, Perry F.; Lukas, Scott E.

    2009-01-01

    SUMMARY Insomnia afflicts many individuals, but particularly those in chronic methadone treatment. Studies examining sleep deprivation (SD) have begun to identify sleep restoration processes involving brain bioenergetics. The technique [31]P magnetic resonance spectroscopy (MRS) can measure brain changes in the high-energy phosphates: alpha-, beta-, and gamma-nucleoside triphosphate (NTP). In the present study, 21 methadone-maintained (MM) and 16 control participants underwent baseline (BL), SD (40 wakeful hrs), recovery1 (RE1), and recovery2 (RE2) study nights. Polysomnographic sleep was recorded each night and [31]P MRS brain scanning conducted each morning using a 4T MR scanner (dual-tuned proton/phosphorus headcoil). Interestingly, increases in total sleep time (TST) and sleep efficiency index (SEI) commonly associated with RE sleep were not apparent in MM participants. Analysis of methadone treatment duration revealed that the lack of RE sleep increases in TST and SEI were primarily exhibited by short-term MM participants (methadone<12 months), while RE sleep in long-term MM (methadone>12 months) participants was more comparable to control participants. Slow wave sleep increased during RE1, but there was no difference between MM and control participants. Spectral power analysis revealed that compared to control participants; MM participants had greater delta, theta, and alpha spectral power during BL and RE sleep. [31]P MRS revealed that elevations in brain beta-NTP (a direct measure of ATP) following RE sleep were greater in MM compared to control participants. Results suggest that differences in sleep and brain chemistry during RE in MM participants may be reflective of a disruption in homeostatic sleep function. PMID:19775835

  15. 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…

  16. Regioselective Hydration of an Alkene and Analysis of the Alcohol Product by Remote Access NMR: A Classroom Demonstration

    ERIC Educational Resources Information Center

    Smith, Maureen E.; Johnson, Sara L.; Masterson, Douglas S.

    2013-01-01

    A two-part demonstration was conducted in our first-semester organic chemistry course designed to introduce students to the formation of alcohols, regioselective reactions, and analysis of organic products by NMR analysis. This demonstration utilized the oxymercuration-demercuration sequence to prepare an alcohol from an alkene in a Markovnikov…

  17. Simultaneous Gaussian and exponential inversion for improved analysis of shales by NMR relaxometry.

    PubMed

    Washburn, Kathryn E; Anderssen, Endre; Vogt, Sarah J; Seymour, Joseph D; Birdwell, Justin E; Kirkland, Catherine M; Codd, Sarah L

    2015-01-01

    Nuclear magnetic resonance (NMR) relaxometry is commonly used to provide lithology-independent porosity and pore-size estimates for petroleum resource evaluation based on fluid-phase signals. However in shales, substantial hydrogen content is associated with solid and fluid signals and both may be detected. Depending on the motional regime, the signal from the solids may be best described using either exponential or Gaussian decay functions. When the inverse Laplace transform, the standard method for analysis of NMR relaxometry results, is applied to data containing Gaussian decays, this can lead to physically unrealistic responses such as signal or porosity overcall and relaxation times that are too short to be determined using the applied instrument settings. We apply a new simultaneous Gaussian-Exponential (SGE) inversion method to simulated data and measured results obtained on a variety of oil shale samples. The SGE inversion produces more physically realistic results than the inverse Laplace transform and displays more consistent relaxation behavior at high magnetic field strengths. Residuals for the SGE inversion are consistently lower than for the inverse Laplace method and signal overcall at short T2 times is mitigated. Beyond geological samples, the method can also be applied in other fields where the sample relaxation consists of both Gaussian and exponential decays, for example in material, medical and food sciences. PMID:25459882

  18. Simultaneous Gaussian and exponential inversion for improved analysis of shales by NMR relaxometry

    USGS Publications Warehouse

    Washburn, Kathryn E.; Anderssen, Endre; Vogt, Sarah J.; Seymour, Joseph D.; Birdwell, Justin E.; Kirkland, Catherine M.; Codd, Sarah L.

    2014-01-01

    Nuclear magnetic resonance (NMR) relaxometry is commonly used to provide lithology-independent porosity and pore-size estimates for petroleum resource evaluation based on fluid-phase signals. However in shales, substantial hydrogen content is associated with solid and fluid signals and both may be detected. Depending on the motional regime, the signal from the solids may be best described using either exponential or Gaussian decay functions. When the inverse Laplace transform, the standard method for analysis of NMR relaxometry results, is applied to data containing Gaussian decays, this can lead to physically unrealistic responses such as signal or porosity overcall and relaxation times that are too short to be determined using the applied instrument settings. We apply a new simultaneous Gaussian-Exponential (SGE) inversion method to simulated data and measured results obtained on a variety of oil shale samples. The SGE inversion produces more physically realistic results than the inverse Laplace transform and displays more consistent relaxation behavior at high magnetic field strengths. Residuals for the SGE inversion are consistently lower than for the inverse Laplace method and signal overcall at short T2 times is mitigated. Beyond geological samples, the method can also be applied in other fields where the sample relaxation consists of both Gaussian and exponential decays, for example in material, medical and food sciences.

  19. Simultaneous Gaussian and exponential inversion for improved analysis of shales by NMR relaxometry

    NASA Astrophysics Data System (ADS)

    Washburn, Kathryn E.; Anderssen, Endre; Vogt, Sarah J.; Seymour, Joseph D.; Birdwell, Justin E.; Kirkland, Catherine M.; Codd, Sarah L.

    2015-01-01

    Nuclear magnetic resonance (NMR) relaxometry is commonly used to provide lithology-independent porosity and pore-size estimates for petroleum resource evaluation based on fluid-phase signals. However in shales, substantial hydrogen content is associated with solid and fluid signals and both may be detected. Depending on the motional regime, the signal from the solids may be best described using either exponential or Gaussian decay functions. When the inverse Laplace transform, the standard method for analysis of NMR relaxometry results, is applied to data containing Gaussian decays, this can lead to physically unrealistic responses such as signal or porosity overcall and relaxation times that are too short to be determined using the applied instrument settings. We apply a new simultaneous Gaussian-Exponential (SGE) inversion method to simulated data and measured results obtained on a variety of oil shale samples. The SGE inversion produces more physically realistic results than the inverse Laplace transform and displays more consistent relaxation behavior at high magnetic field strengths. Residuals for the SGE inversion are consistently lower than for the inverse Laplace method and signal overcall at short T2 times is mitigated. Beyond geological samples, the method can also be applied in other fields where the sample relaxation consists of both Gaussian and exponential decays, for example in material, medical and food sciences.

  20. Structural Analysis of N- and O-glycans Using ZIC-HILIC/Dialysis Coupled to NMR Detection

    SciTech Connect

    Qu, Yi; Feng, Ju; Deng, Shuang; Cao, Li; Zhang, Qibin; Zhao, Rui; Zhang, Zhaorui; Jiang, Yuxuan; Zink, Erika M.; Baker, Scott E.; Lipton, Mary S.; Pasa-Tolic, Ljiljana; Hu, Jian Z.; Wu, Si

    2014-11-19

    Protein glycosylation, an important and complex post-translational modification (PTM), is involved in various biological processes including the receptor-ligand and cell-cell interaction, and plays a crucial role in many biological functions. However, little is known about the glycan structures of important biological complex samples, and the conventional glycan enrichment strategy (i.e., size-exclusion column [SEC] separation,) prior to nuclear magnetic resonance (NMR) detection is time-consuming and tedious. In this study, we employed SEC, Zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC), and ZIC-HILIC coupled with dialysis strategies to enrich the glycopeptides from the pronase E digests of RNase B, followed by NMR analysis of the glycoconjugate. Our results suggest that the ZIC-HILIC enrichment coupled with dialysis is the most efficient, which was thus applied to the analysis of biological complex sample, the pronase E digest of the secreted proteins from the fungi Aspergillus niger. The NMR spectra revealed that the secreted proteins from A. niger contain both N-linked glycans with a high-mannose core and O-linked glycans bearing mannose and glucose with 1->3 and 1->6 linkages. In all, our study provides compelling evidence that ZIC-HILIC separation coupled to dialysis is superior to the commonly used SEC separation to prepare glycopeptides for the downstream NMR analysis, which could greatly facilitate the future NMR-based glycoproteomics research.

  1. NMR analysis of the human saliva metabolome distinguishes dementia patients from matched controls.

    PubMed

    Figueira, João; Jonsson, Pär; Nordin Adolfsson, Annelie; Adolfsson, Rolf; Nyberg, Lars; Öhman, Anders

    2016-07-19

    Saliva is a biofluid that is sensitive to metabolic changes and is straightforward to collect in a non-invasive manner, but it is seldom used for metabolite analysis when studying neurodegenerative disorders. We present a procedure for both an untargeted and targeted analysis of the saliva metabolome in which nuclear magnetic resonance (NMR) spectroscopy is used in combination with multivariate data analysis. The applicability of this approach is demonstrated on saliva samples selected from the 25 year prospective Betula study, including samples from dementia subjects with either Alzheimer's disease (AD) or vascular dementia at the time of sampling or who developed it by the next sampling/assessment occasion five years later, and age-, gender-, and education-matched control individuals without dementia. Statistically significant multivariate models were obtained that separated patients with dementia from controls and revealed seven discriminatory metabolites. Dementia patients showed significantly increased concentrations of acetic acid (fold change (fc) = 1.25, p = 2 × 10(-5)), histamine (fc = 1.26, p = 0.019), and propionate (fc = 1.35, p = 0.002), while significantly decreased levels were observed for dimethyl sulfone (fc = 0.81, p = 0.005), glycerol (fc = 0.79, p = 0.04), taurine (fc = 0.70, p = 0.007), and succinate (fc = 0.62, p = 0.008). Histamine, succinate, and taurine are known to be important in AD, and acetic acid and glycerol are involved in related pathways. Dimethyl sulfone and propionate originate from the diet and bacterial flora and might reflect poorer periodontal status in the dementia patients. For these seven metabolites, a weak but statistically significant pre-diagnostic value was observed. Taken together, we present a robust and general NMR analysis approach for studying the saliva metabolome that has potential use for screening and early detection of dementia. PMID:27265744

  2. Two-dimensional NMR spectroscopy strongly enhances soil organic matter composition analysis

    NASA Astrophysics Data System (ADS)

    Soucemarianadin, Laure; Erhagen, Björn; Öquist, Mats; Nilsson, Mats; Hedenström, Mattias; Schleucher, Jürgen

    2016-04-01

    Soil organic matter (SOM) is the largest terrestrial carbon pool and strongly affects soil properties. With climate change, understanding SOM processes and turnover and how they could be affected by increasing temperatures becomes critical. This is particularly key for organic soils as they represent a huge carbon pool in very sensitive ecosystems, like boreal ecosystems and peatlands. Nevertheless, characterization of SOM molecular composition, which is essential to elucidate soil carbon processes, is not easily achieved, and further advancements in that area are greatly needed. Solid-state one-dimensional (1D) 13C nuclear magnetic resonance (NMR) spectroscopy is often used to characterize its molecular composition, but only provides data on a few major functional groups, which regroup many different molecular fragments. For instance, in the carbohydrates region, signals of all monosaccharides present in many different polymers overlap. This overlap thwarts attempts to identify molecular moieties, resulting in insufficient information to characterize SOM composition. Here we show that two-dimensional (2D) liquid-state 1H-13C NMR spectra provided much richer data on the composition of boreal plant litter and organic surface soil. The 2D spectra indeed resolved overlaps observed in 1D 13C spectra and displayed signals from hundreds of identifiable molecular groups. For example, in the aromatics region, signals from individual lignin units could be recognized. It was hence possible to follow the fate of specific structural moieties in soils. We observed differences between litter and soil samples, and were able to relate them to the decomposition of identifiable moieties. Sample preparation and data acquisition were both simple and fast. Further, using multivariate data analysis, we aimed at linking the detailed chemical fingerprints of SOM to turnover rates in a soil incubation experiment. With the multivariate models, we were able to identify specific molecular

  3. Independent components analysis to increase efficiency of discriminant analysis methods (FDA and LDA): Application to NMR fingerprinting of wine.

    PubMed

    Monakhova, Yulia B; Godelmann, Rolf; Kuballa, Thomas; Mushtakova, Svetlana P; Rutledge, Douglas N

    2015-08-15

    Discriminant analysis (DA) methods, such as linear discriminant analysis (LDA) or factorial discriminant analysis (FDA), are well-known chemometric approaches for solving classification problems in chemistry. In most applications, principle components analysis (PCA) is used as the first step to generate orthogonal eigenvectors and the corresponding sample scores are utilized to generate discriminant features for the discrimination. Independent components analysis (ICA) based on the minimization of mutual information can be used as an alternative to PCA as a preprocessing tool for LDA and FDA classification. To illustrate the performance of this ICA/DA methodology, four representative nuclear magnetic resonance (NMR) data sets of wine samples were used. The classification was performed regarding grape variety, year of vintage and geographical origin. The average increase for ICA/DA in comparison with PCA/DA in the percentage of correct classification varied between 6±1% and 8±2%. The maximum increase in classification efficiency of 11±2% was observed for discrimination of the year of vintage (ICA/FDA) and geographical origin (ICA/LDA). The procedure to determine the number of extracted features (PCs, ICs) for the optimum DA models was discussed. The use of independent components (ICs) instead of principle components (PCs) resulted in improved classification performance of DA methods. The ICA/LDA method is preferable to ICA/FDA for recognition tasks based on NMR spectroscopic measurements.

  4. Quantitative analysis of cyclic dimer fatty acid content in the dimerization product by proton NMR spectroscopy.

    PubMed

    Park, Kyun Joo; Kim, Minyoung; Seok, Seunghwan; Kim, Young-Wun; Kim, Do Hyun

    2015-01-01

    In this work, (1)H NMR is utilized for the quantitative analysis of a specific cyclic dimer fatty acid in a dimer acid mixture using the pseudo-standard material of mesitylene on the basis of its structural similarity. Mesitylene and cyclic dimer acid levels were determined using the signal of the proton on the cyclic ring (δ=6.8) referenced to the signal of maleic acid (δ=6.2). The content of the cyclic dimer fatty acid was successfully determined through the standard curve of mesitylene and the reported equation. Using the linearity of the mesitylene curve, the cyclic dimer fatty acid in the oil mixture was quantified. The results suggest that the proposed method can be used to quantify cyclic compounds in mixtures to optimize the dimerization process.

  5. Analysis of Hydroperoxides in Solid Polyethylene by MAS (13)C NMR and EPR

    SciTech Connect

    ASSINK,ROGER A.; CELINA,MATHIAS C.; DUNBAR,TIMOTHY D.; ALAM,TODD M.; CLOUGH,ROGER LEE; GILLEN,KENNETH T.

    1999-11-19

    {sup 13}C-enriched polyethylene was subjected to {gamma}-irradiation in the presence of air at 25 and 80 C for total doses ranging from 71 to 355 kGy. Significant quantities of hydroperoxides were detected in the 25 C irradiated sample by {sup 13}C magic angle spinning NMR spectroscopy. This method of detection was performed on the solid polymer and required no chemical derivatization or addition of solvent. The chemical stability and subsequent products of the hydroperoxide species were studied by annealing the irradiated samples in air at temperatures ranging from 22 to 110 C. A time-temperature superposition analysis provided an activation energy of 108 kJ/mol for the hydroperoxide decomposition process. The primary products of hydroperoxide decomposition were ketones and secondary alcohols with lesser amounts of acids and esters. EPR measurements suggest that the reactive hydroperoxide species reside in the amorphous phase of polyethylene, consistent with degradation occurring in the amorphous phase.

  6. Untargeted NMR Spectroscopic Analysis of the Metabolic Variety of New Apple Cultivars.

    PubMed

    Eisenmann, Philipp; Ehlers, Mona; Weinert, Christoph H; Tzvetkova, Pavleta; Silber, Mara; Rist, Manuela J; Luy, Burkhard; Muhle-Goll, Claudia

    2016-01-01

    Metabolome analyses by NMR spectroscopy can be used in quality control by generating unique fingerprints of different species. Hundreds of components and their variation between different samples can be analyzed in a few minutes/hours with high accuracy and low cost of sample preparation. Here, apple peel and pulp extracts of a variety of apple cultivars were studied to assess their suitability to discriminate between the different varieties. The cultivars comprised mainly newly bred varieties or ones that were brought onto the market in recent years. Multivariate analyses of peel and pulp extracts were able to unambiguously identify all cultivars, with peel extracts showing a higher discriminative power. The latter was increased if the highly concentrated sugar metabolites were omitted from the analysis. Whereas sugar concentrations lay within a narrow range, polyphenols, discussed as potential health promoting substances, and acids varied remarkably between the cultivars. PMID:27657148

  7. NMR Based Cerebrum Metabonomic Analysis Reveals Simultaneous Interconnected Changes during Chick Embryo Incubation.

    PubMed

    Feng, Yue; Zhu, Hang; Zhang, Xu; Wang, Xuxia; Xu, Fuqiang; Tang, Huiru; Ye, Chaohui; Liu, Maili

    2015-01-01

    To find out if content changes of the major functional cerebrum metabolites are interconnected and formed a network during the brain development, we obtained high-resolution magic-angle-spinning (HR-MAS) 1H NMR spectra of cerebrum tissues of chick embryo aged from incubation day 10 to 20, and postnatal day 1, and analyzed the data with principal component analysis (PCA). Within the examined time window, 26 biological important molecules were identified and 12 of them changed their relative concentration significantly in a time-dependent manner. These metabolites are generally belonged to three categories, neurotransmitters, nutrition sources, and neuronal or glial markers. The relative concentration changes of the metabolites were interconnected among/between the categories, and, more interestingly, associated with the number and size of Nissl-positive neurons. These results provided valuable biochemical and neurochemical information to understand the development of the embryonic brain.

  8. Comprehensive triblock copolymer analysis by coupled thermal field-flow fractionation-NMR.

    PubMed

    van Aswegen, Werner; Hiller, Wolf; Hehn, Mathias; Pasch, Harald

    2013-07-12

    Thermal field-flow fractionation (ThFFF) is used as a novel fractionation technique to investigate the molecular heterogeneity of PB-b-PVP-b-PtBMA triblock copolymers. Such copolymers cause major problems in liquid chromatography due to very strong polar interactions with the stationary phase. ThFFF separates the copolymers with regard to size and/or chemical composition based on the normal and thermal diffusion coefficients. The separation mechanism in ThFFF and the chemical composition of the separated species is elucidated by online (1) H NMR. Based on the compositional analysis and a calibration of the system with the respective homopolymers, the samples are quantified regarding their molar masses, chemical compositions, and microstructures providing comprehensive information on the complex structure of these block copolymers. PMID:23722993

  9. Tannin structural elucidation and quantitative ³¹P NMR analysis. 1. Model compounds.

    PubMed

    Melone, Federica; Saladino, Raffaele; Lange, Heiko; Crestini, Claudia

    2013-10-01

    Tannins and flavonoids are secondary metabolites of plants that display a wide array of biological activities. This peculiarity is related to the inhibition of extracellular enzymes that occurs through the complexation of peptides by tannins. Not only the nature of these interactions, but more fundamentally also the structure of these heterogeneous polyphenolic molecules are not completely clear. This first paper describes the development of a new analytical method for the structural characterization of tannins on the basis of tannin model compounds employing an in situ labeling of all labile H groups (aliphatic OH, phenolic OH, and carboxylic acids) with a phosphorus reagent. The ³¹P NMR analysis of ³¹P-labeled samples allowed the unprecedented quantitative and qualitative structural characterization of hydrolyzable tannins, proanthocyanidins, and catechin tannin model compounds, forming the foundations for the quantitative structural elucidation of a variety of actual tannin samples described in part 2 of this series. PMID:24059814

  10. NMR Based Cerebrum Metabonomic Analysis Reveals Simultaneous Interconnected Changes during Chick Embryo Incubation

    PubMed Central

    Feng, Yue; Zhu, Hang; Zhang, Xu; Wang, Xuxia; Xu, Fuqiang; Tang, Huiru; Ye, Chaohui; Liu, Maili

    2015-01-01

    To find out if content changes of the major functional cerebrum metabolites are interconnected and formed a network during the brain development, we obtained high-resolution magic-angle-spinning (HR-MAS) 1H NMR spectra of cerebrum tissues of chick embryo aged from incubation day 10 to 20, and postnatal day 1, and analyzed the data with principal component analysis (PCA). Within the examined time window, 26 biological important molecules were identified and 12 of them changed their relative concentration significantly in a time-dependent manner. These metabolites are generally belonged to three categories, neurotransmitters, nutrition sources, and neuronal or glial markers. The relative concentration changes of the metabolites were interconnected among/between the categories, and, more interestingly, associated with the number and size of Nissl-positive neurons. These results provided valuable biochemical and neurochemical information to understand the development of the embryonic brain. PMID:26485040

  11. Untargeted NMR Spectroscopic Analysis of the Metabolic Variety of New Apple Cultivars

    PubMed Central

    Eisenmann, Philipp; Ehlers, Mona; Weinert, Christoph H.; Tzvetkova, Pavleta; Silber, Mara; Rist, Manuela J.; Luy, Burkhard; Muhle-Goll, Claudia

    2016-01-01

    Metabolome analyses by NMR spectroscopy can be used in quality control by generating unique fingerprints of different species. Hundreds of components and their variation between different samples can be analyzed in a few minutes/hours with high accuracy and low cost of sample preparation. Here, apple peel and pulp extracts of a variety of apple cultivars were studied to assess their suitability to discriminate between the different varieties. The cultivars comprised mainly newly bred varieties or ones that were brought onto the market in recent years. Multivariate analyses of peel and pulp extracts were able to unambiguously identify all cultivars, with peel extracts showing a higher discriminative power. The latter was increased if the highly concentrated sugar metabolites were omitted from the analysis. Whereas sugar concentrations lay within a narrow range, polyphenols, discussed as potential health promoting substances, and acids varied remarkably between the cultivars. PMID:27657148

  12. Quantitative analysis of sesquiterpene lactones in extract of Arnica montana L. by 1H NMR spectroscopy.

    PubMed

    Staneva, Jordanka; Denkova, Pavletta; Todorova, Milka; Evstatieva, Ljuba

    2011-01-01

    (1)H NMR spectroscopy was used as a method for quantitative analysis of sesquiterpene lactones present in a crude lactone fraction isolated from Arnica montana. Eight main components - tigloyl-, methacryloyl-, isobutyryl- and 2-methylbutyryl-esters of helenalin (H) and 11α,13-dihydrohelenalin (DH) were identified in the studied sample. The method allows the determination of the total amount of sesquiterpene lactones and the quantity of both type helenalin and 11α,13-dihydrohelenalin esters separately. Furthermore, 6-O-tigloylhelenalin (HT, 1), 6-O-methacryloylhelenalin (HM, 2), 6-O-tigloyl-11α,13-dihydrohelenalin (DHT, 5), and 6-O-methacryloyl-11α,13-dihydrohelenalin (DHM, 6) were quantified as individual components.

  13. Ultrafast multidimensional Laplace NMR for a rapid and sensitive chemical analysis.

    PubMed

    Ahola, Susanna; Zhivonitko, Vladimir V; Mankinen, Otto; Zhang, Guannan; Kantola, Anu M; Chen, Hsueh-Ying; Hilty, Christian; Koptyug, Igor V; Telkki, Ville-Veikko

    2015-09-18

    Traditional nuclear magnetic resonance (NMR) spectroscopy relies on the versatile chemical information conveyed by spectra. To complement conventional NMR, Laplace NMR explores diffusion and relaxation phenomena to reveal details on molecular motions. Under a broad concept of ultrafast multidimensional Laplace NMR, here we introduce an ultrafast diffusion-relaxation correlation experiment enhancing the resolution and information content of corresponding 1D experiments as well as reducing the experiment time by one to two orders of magnitude or more as compared with its conventional 2D counterpart. We demonstrate that the method allows one to distinguish identical molecules in different physical environments and provides chemical resolution missing in NMR spectra. Although the sensitivity of the new method is reduced due to spatial encoding, the single-scan approach enables one to use hyperpolarized substances to boost the sensitivity by several orders of magnitude, significantly enhancing the overall sensitivity of multidimensional Laplace NMR.

  14. Ultrafast multidimensional Laplace NMR for a rapid and sensitive chemical analysis

    PubMed Central

    Ahola, Susanna; Zhivonitko, Vladimir V; Mankinen, Otto; Zhang, Guannan; Kantola, Anu M.; Chen, Hsueh-Ying; Hilty, Christian; Koptyug, Igor V.; Telkki, Ville-Veikko

    2015-01-01

    Traditional nuclear magnetic resonance (NMR) spectroscopy relies on the versatile chemical information conveyed by spectra. To complement conventional NMR, Laplace NMR explores diffusion and relaxation phenomena to reveal details on molecular motions. Under a broad concept of ultrafast multidimensional Laplace NMR, here we introduce an ultrafast diffusion-relaxation correlation experiment enhancing the resolution and information content of corresponding 1D experiments as well as reducing the experiment time by one to two orders of magnitude or more as compared with its conventional 2D counterpart. We demonstrate that the method allows one to distinguish identical molecules in different physical environments and provides chemical resolution missing in NMR spectra. Although the sensitivity of the new method is reduced due to spatial encoding, the single-scan approach enables one to use hyperpolarized substances to boost the sensitivity by several orders of magnitude, significantly enhancing the overall sensitivity of multidimensional Laplace NMR. PMID:26381101

  15. Ultrafast multidimensional Laplace NMR for a rapid and sensitive chemical analysis

    NASA Astrophysics Data System (ADS)

    Ahola, Susanna; Zhivonitko, Vladimir V.; Mankinen, Otto; Zhang, Guannan; Kantola, Anu M.; Chen, Hsueh-Ying; Hilty, Christian; Koptyug, Igor V.; Telkki, Ville-Veikko

    2015-09-01

    Traditional nuclear magnetic resonance (NMR) spectroscopy relies on the versatile chemical information conveyed by spectra. To complement conventional NMR, Laplace NMR explores diffusion and relaxation phenomena to reveal details on molecular motions. Under a broad concept of ultrafast multidimensional Laplace NMR, here we introduce an ultrafast diffusion-relaxation correlation experiment enhancing the resolution and information content of corresponding 1D experiments as well as reducing the experiment time by one to two orders of magnitude or more as compared with its conventional 2D counterpart. We demonstrate that the method allows one to distinguish identical molecules in different physical environments and provides chemical resolution missing in NMR spectra. Although the sensitivity of the new method is reduced due to spatial encoding, the single-scan approach enables one to use hyperpolarized substances to boost the sensitivity by several orders of magnitude, significantly enhancing the overall sensitivity of multidimensional Laplace NMR.

  16. Nuclear Magnetic Resonance (NMR) analysis of a Kel-F resin and lacquer

    NASA Astrophysics Data System (ADS)

    Rutenberg, A. C.

    1985-08-01

    Proton, carbon, and fluorine nuclear magnetic resonance (NMR) spectroscopy has been used at the Oak Ridge Y-12 Plant to determine the concentration of various species present in Kel-F 800 resin and its lacquers. Nuclear magnetic resonance (NMR) spectroscopy has been used to characterize Kel-F 800 resin and to measure the various chemical species present in a lacquer based on this resin. Proton NMR spectroscopy was used to measure the ratio of ethyl acetate to xylenes and to estimate the vinylidene fluoride content of the resin. Fluorine NMR spectroscopy was used to determine the water and ethanol content of the lacquer as well as some of its components. Fluorine NMR spectroscopy was also used to estimate the amount of perfluorodecanoate emulsifier present in the Kel-F resin. Carbon-13 NMR spectroscopy was used to determine the isomeric composition of various batches of xylenes and as an alternate method for measuring the vinylidene fluoride content of the resin.

  17. Solubility and Thermal Stability Investigation of Titan Tholins: New Insight from NMR Analysis

    NASA Astrophysics Data System (ADS)

    He, Chao; Smith, M. A.

    2012-10-01

    We investigated the solubility and thermal stability of Titan’s aerosol analogs (tholins) to understand the basic property of organics on Titan and the potential for chemical modification upon in situ sampling. The tholin generated by AC discharge in CH4/N2 (5/95) mixture preferentially dissolves in polar solvent to non-polar solvent, totally soluble in DMSO (>21.5 mg/mL), 60% in mass soluble in methanol, 25% in acetone, 27% in acetonitrile and 30% in water while only 1% in benzene and chloroform. The 1H solution-state NMR spectra of respective deuterated solutions exhibit the structural information of the soluble fraction in each solvent, confirming the large percentage of polar species in tholins. The solubility study not only helps us understand the solubility of Titan’s aerosols in possible liquid phase in Titan’s surface/atmosphere, but also provides the basis for the solvent selection and methods development of liquid separation and/or solution based analysis in future Titan missions. These include methods such as NMR and LC/MS, which can be non-destructive providing objective information regarding nascent chemical identification. Thermal stability studies demonstrate the thermal lability of tholins and indicate significant structural changes of when heated beyond 150 oC for even short time periods in inert atmospheres. Dynamic studies at 200 oC demonstrate that several predominant chemical reactions fit first-order reaction kinetics with half-lives between 5 to 141 minutes. This study is critical to ongoing discussion regarding the development of in situ analysis methods and instruments for Titan mission and other outer planet exploration.

  18. 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

  19. Intracellular pH measurement in frog muscle by means of 31P-nuclear magnetic resonance.

    PubMed

    Yoshizaki, K; Nishikawa, H; Yamada, S; Morimoto, T; Watari, H

    1979-01-01

    The 31P-NMR technique was used for the monitoring of intracellular pH and studying its heterogeneity in the femoral biceps muscle of Rana catesbiana under anaerobic conditions. The value of intracellular pH of fresh muscle calculated from the chemical shift of intracellular inorganic phosphate (P1) was 7.3 on average and the line width of P1 was about 0.2 ppm. As the line width determined by the relaxation mechanism was 0.099 ppm, the P1 signal in fresh muscle was concluded to consist of overlapped narrow components, which indicated the heterogeneity of muscular pH (about 0.2 pH unit). Living muscle showed gradual acidification due to glycolysis and the decrease in heterogeneity. When glycolysis was suppressed by iodoacetic acid, slight alkalization due to the breakdown of creatine phosphate was observed. When the Lohmann reaction was suppressed by 2, 4-dinitro-1-fluorobenzene, rapid acidification accompanied by the appearance of a new acidic component was observed with the onset of ATP decrease. This new component was not detected in the muscle pretreated with glycerol to disrupt the transverse tubules. Therefore, it is likely that this new acidic component originates in the intracellular compartment, and not in the cellular difference. PMID:40052

  20. 31P-saturation-transfer nuclear-magnetic-resonance measurements of phosphocreatine turnover in guinea-pig brain slices.

    PubMed

    Morris, P G; Feeney, J; Cox, D W; Bachelard, H S

    1985-05-01

    The technique of 31P saturation-transfer n.m.r. was used to determine the forward and the reverse rate constants of creatine phosphotransferase in superfused guinea-pig cerebral tissues in vitro. The calculated forward rate constant of 0.22 +/- 0.03s-1 compared well with a previously reported value for rat brain in vivo [Shoubridge, Briggs & Radda (1982) FEBS Lett. 140, 288-292]. The reverse rate constant was found to be 0.55 +/- 0.10s-1. 3. By using concentrations of ATP and phosphocreatine estimated previously for this superfused preparation [Cox, Morris, Feeney & Bachelard (1983) Biochem. J. 212, 365-370], forward and reverse flux rates were calculated to be 0.68 and 0.72 mumol X s-1 X g-1 respectively. The concordance of forward and reverse fluxes contrasts with the situation observed in vitro in other tissues, and suggests that the creatine phosphotransferase reaction is at equilibrium under the conditions used here. 4. Lowering the concentration of glucose in the superfusing medium from 10mM to 0.5mM had no significant effect on phosphocreatine concentration or on the forward (ATP-generating) flux through creatine phosphotransferase. The results indicate that a normal phosphocreatine content in the presence of lowered glucose availability is reflected by an unchanged turnover rate.

  1. Evaluation of an electrochemical model of erythrocyte pH buffering using 31P nuclear magnetic resonance data

    PubMed Central

    1990-01-01

    When erythrocytes are suspended in a solution of known composition the resultant values of such basic cell parameters as volume and pH are difficult to predict. To facilitate such predictions, we developed a mathematical model describing the passive transmembrane distribution of permeant species; three simultaneous equations were produced. Certain essential data required for the model were determined experimentally; these included the pH dependence of the charge on the hemoglobin molecule and the variation of the osmotic coefficient of hemoglobin with cell volume. Finally, cells were added to various solutions, and then titrated to produce a wide pH range (pH 6-8). We measured the resultant cell volume, cellular and extracellular pH using both conventional and 31P NMR methods. The expected equilibrium values of these electrochemical parameters were also calculated by solving (numerically) the three model equations. The accuracy of the model simulations was evaluated by direct comparison of calculated and experimentally determined values. PMID:2374002

  2. Bacterial spore detection and analysis using hyperpolarized 129Xe chemical exchange saturation transfer (Hyper-CEST) NMR

    PubMed Central

    Bai, Yubin; Wang, Yanfei; Goulian, Mark; Driks, Adam

    2014-01-01

    Previously, we reported hyperpolarized 129Xe chemical exchange saturation transfer (Hyper-CEST) NMR techniques for the ultrasensitive (i.e., 1 picomolar) detection of xenon host molecules known as cryptophane. Here, we demonstrate a more general role for Hyper-CEST NMR as a spectroscopic method for probing nanoporous structures, without the requirement for cryptophane or engineered xenon-binding sites. Hyper-CEST 129Xe NMR spectroscopy was employed to detect Bacillus anthracis and Bacillus subtilis spores in solution, and interrogate the layers that comprise their structures. 129Xe-spore samples were selectively irradiated with radiofrequency pulses; the depolarized 129Xe returned to aqueous solution and depleted the 129Xe-water signal, providing measurable contrast. Removal of the outermost spore layers in B. anthracis and B. subtilis (the exosporium and coat, respectively) enhanced 129Xe exchange with the spore interior. Notably, the spores were invisible to hyperpolarized 129Xe NMR direct detection methods, highlighting the lack of high-affinity xenon-binding sites, and the potential for extending Hyper-CEST NMR structural analysis to other biological and synthetic nanoporous structures. PMID:25089181

  3. 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.

  4. NMR and IR Spectroscopy for the Structural Characterization of Edible Fats and Oils: An Instrumental Analysis Laboratory

    ERIC Educational Resources Information Center

    Crowther, Molly W.

    2008-01-01

    This article describes an upper-level instrumental laboratory for undergraduates that explores the complementary nature of IR and NMR spectroscopy for analysis of several edible fats and oils that are structurally similar but differ in physical properties and health implications. Five different fats and oils are analyzed for average chain length,…

  5. Complex mixture analysis of organic compounds in green coffee bean extract by two-dimensional NMR spectroscopy.

    PubMed

    Wei, Feifei; Furihata, Kazuo; Hu, Fangyu; Miyakawa, Takuya; Tanokura, Masaru

    2010-11-01

    A complex mixture analysis by one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy was carried out for the first time for the identification and quantification of organic compounds in green coffee bean extract (GCBE). A combination of (1)H-(1)H DQF-COSY, (1)H-(13)C HSQC, and (1)H-(13)C CT-HMBC two-dimensional sequences was used, and 16 compounds were identified. In particular, three isomers of caffeoylquinic acid were identified in the complex mixture without any separation. In addition, GCBE components were quantified by the integration of carbon signals by use of a relaxation reagent and an inverse-gated decoupling method without a nuclear Overhauser effect. This NMR methodology provides detailed information about the kinds and amounts of GCBE components, and in our study, the chemical makeup of GCBE was clarified by the NMR results.

  6. 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.

  7. Characterising the rheology of non-Newtonian fluids using PFG-NMR and cumulant analysis.

    PubMed

    Blythe, T W; Sederman, A J; Mitchell, J; Stitt, E H; York, A P E; Gladden, L F

    2015-06-01

    Conventional rheological characterisation using nuclear magnetic resonance (NMR) typically utilises spatially-resolved measurements of velocity. We propose a new approach to rheometry using pulsed field gradient (PFG) NMR which readily extends the application of MR rheometry to single-axis gradient hardware. The quantitative use of flow propagators in this application is challenging because of the introduction of artefacts during Fourier transform, which arise when realistic sampling strategies are limited by experimental and hardware constraints and when particular spatial and temporal resolution are required. The method outlined in this paper involves the cumulant analysis of the acquisition data directly, thereby preventing the introduction of artefacts and reducing data acquisition times. A model-dependent approach is developed to enable the pipe-flow characterisation of fluids demonstrating non-Newtonian power-law rheology, involving the use of an analytical expression describing the flow propagator in terms of the flow behaviour index. The sensitivity of this approach was investigated and found to be robust to the signal-to-noise ratio (SNR) and number of acquired data points, enabling an increase in temporal resolution defined by the SNR. Validation of the simulated results was provided by an experimental case study on shear-thinning aqueous xanthan gum solutions, whose rheology could be accurately characterised using a power-law model across the experimental shear rate range of 1-100 s(-1). The flow behaviour indices calculated using this approach were observed to be within 8% of those obtained using spatially-resolved velocity imaging and within 5% of conventional rheometry. Furthermore, it was shown that the number of points sampled could be reduced by a factor of 32, when compared to the acquisition of a volume-averaged flow propagator with 128 gradient increments, without negatively influencing the accuracy of the characterisation, reducing the

  8. NMR-based lipidomic analysis of blood lipoproteins differentiates the progression of coronary heart disease.

    PubMed

    Kostara, Christina E; Papathanasiou, Athanasios; Psychogios, Nikolaos; Cung, Manh Thong; Elisaf, Moses S; Goudevenos, John; Bairaktari, Eleni T

    2014-05-01

    Abnormal lipid composition and metabolism of plasma lipoproteins play a crucial role in the pathogenesis of coronary heart disease (CHD). A (1)H NMR-based lipidomic approach was used to investigate the correlation of coronary artery stenosis with the atherogenic (non-HDL) and atheroprotective (HDL) lipid profiles in 99 patients with CHD of various stages of disease and compared with 60 patients with normal coronary arteries (NCA), all documented in coronary angiography. The pattern recognition models created from lipid profiles predicted the presence of CHD with a sensitivity of 87% and a specificity of 88% in the HDL model and with 90% and 89% in the non-HDL model, respectively. Patients with mild, moderate, and severe coronary artery stenosis were progressively differentiated from those with NCA in the non-HDL model with a statistically significant separation of severe stage from both mild and moderate. In the HDL model, the progressive differentiation of the disease stages was statistically significant only between patients with mild and severe coronary artery stenosis. The lipid constituents of lipoproteins that mainly characterized the initial stages and then the progression of the disease were the high levels of saturated fatty acids in lipids in both HDL and non-HDL particles, the low levels of HDL-phosphatidylcholine, HDL-sphingomyelin, and omega-3 fatty acids and linoleic acid in lipids in non-HDL particles. The conventional lipid marker, total cholesterol, found in low levels in HDL and in high levels in non-HDL, also contributed to the onset of the disease but with a much lower coefficient of significance. (1)H NMR-based lipidomic analysis of atherogenic and atheroprotective lipoproteins could contribute to the early evaluation of the onset of coronary artery disease and possibly to the establishment of an appropriate therapeutic option.

  9. Characterising the rheology of non-Newtonian fluids using PFG-NMR and cumulant analysis.

    PubMed

    Blythe, T W; Sederman, A J; Mitchell, J; Stitt, E H; York, A P E; Gladden, L F

    2015-06-01

    Conventional rheological characterisation using nuclear magnetic resonance (NMR) typically utilises spatially-resolved measurements of velocity. We propose a new approach to rheometry using pulsed field gradient (PFG) NMR which readily extends the application of MR rheometry to single-axis gradient hardware. The quantitative use of flow propagators in this application is challenging because of the introduction of artefacts during Fourier transform, which arise when realistic sampling strategies are limited by experimental and hardware constraints and when particular spatial and temporal resolution are required. The method outlined in this paper involves the cumulant analysis of the acquisition data directly, thereby preventing the introduction of artefacts and reducing data acquisition times. A model-dependent approach is developed to enable the pipe-flow characterisation of fluids demonstrating non-Newtonian power-law rheology, involving the use of an analytical expression describing the flow propagator in terms of the flow behaviour index. The sensitivity of this approach was investigated and found to be robust to the signal-to-noise ratio (SNR) and number of acquired data points, enabling an increase in temporal resolution defined by the SNR. Validation of the simulated results was provided by an experimental case study on shear-thinning aqueous xanthan gum solutions, whose rheology could be accurately characterised using a power-law model across the experimental shear rate range of 1-100 s(-1). The flow behaviour indices calculated using this approach were observed to be within 8% of those obtained using spatially-resolved velocity imaging and within 5% of conventional rheometry. Furthermore, it was shown that the number of points sampled could be reduced by a factor of 32, when compared to the acquisition of a volume-averaged flow propagator with 128 gradient increments, without negatively influencing the accuracy of the characterisation, reducing the

  10. Characterising the rheology of non-Newtonian fluids using PFG-NMR and cumulant analysis

    NASA Astrophysics Data System (ADS)

    Blythe, T. W.; Sederman, A. J.; Mitchell, J.; Stitt, E. H.; York, A. P. E.; Gladden, L. F.

    2015-06-01

    Conventional rheological characterisation using nuclear magnetic resonance (NMR) typically utilises spatially-resolved measurements of velocity. We propose a new approach to rheometry using pulsed field gradient (PFG) NMR which readily extends the application of MR rheometry to single-axis gradient hardware. The quantitative use of flow propagators in this application is challenging because of the introduction of artefacts during Fourier transform, which arise when realistic sampling strategies are limited by experimental and hardware constraints and when particular spatial and temporal resolution are required. The method outlined in this paper involves the cumulant analysis of the acquisition data directly, thereby preventing the introduction of artefacts and reducing data acquisition times. A model-dependent approach is developed to enable the pipe-flow characterisation of fluids demonstrating non-Newtonian power-law rheology, involving the use of an analytical expression describing the flow propagator in terms of the flow behaviour index. The sensitivity of this approach was investigated and found to be robust to the signal-to-noise ratio (SNR) and number of acquired data points, enabling an increase in temporal resolution defined by the SNR. Validation of the simulated results was provided by an experimental case study on shear-thinning aqueous xanthan gum solutions, whose rheology could be accurately characterised using a power-law model across the experimental shear rate range of 1-100 s-1. The flow behaviour indices calculated using this approach were observed to be within 8% of those obtained using spatially-resolved velocity imaging and within 5% of conventional rheometry. Furthermore, it was shown that the number of points sampled could be reduced by a factor of 32, when compared to the acquisition of a volume-averaged flow propagator with 128 gradient increments, without negatively influencing the accuracy of the characterisation, reducing the

  11. Dipeptide Structural Analysis Using Two-Dimensional NMR for the Undergraduate Advanced Laboratory

    ERIC Educational Resources Information Center

    Gonzalez, Elizabeth; Dolino, Drew; Schwartzenburg, Danielle; Steiger, Michelle A.

    2015-01-01

    A laboratory experiment was developed to introduce students in either an organic chemistry or biochemistry lab course to two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy using simple biomolecules. The goal of this experiment is for students to understand and interpret the information provided by a 2D NMR spectrum. Students are…

  12. NMR (¹H) analysis of crude extracts detects light stress in Beta vulgaris and Spinacia oleracea leaves.

    PubMed

    Guadagno, Carmela Rosaria; Della Greca, Marina; Virzo De Santo, Amalia; D'Ambrosio, Nicola

    2013-07-01

    In highlight stress conditions, the mechanism of non-photochemical quenching (NPQ) of chlorophyll fluorescence is triggered at the chloroplast level. This process allows thermal quenching of the excessive excitation energy and it is strictly related to the efficiency of the xanthophyll cycle. Nowadays, the utilization of the nuclear magnetic resonance (NMR) spectroscopy provides a powerful complementary way for the identification and quantitative analysis of plant metabolites either in vivo or in tissue extracts. Seeing that the oxidative damage caused by light stress in plants and the consequent involvement of pigments are widely studied, NMR spectroscopy can be utilized to compare crude leaf extract at different levels of light stress, allowing an analysis of these compounds. In this paper, the identification of possible relationships between light stress and ¹H NMR signal variations is discussed. The analysis of the ¹H NMR (1D) spectra of two agronomic species (Spinacia oleracea and Beta vulgaris) exposed to different light intensities is presented. In particular, change in carotenoids and xanthophylls signals are analyzed.

  13. 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.

  14. Analysis of Proton NMR in Hydrogen Bonds in Terms of Lone-Pair and Bond Orbital Contributions.

    PubMed

    Sutter, Kiplangat; Aucar, Gustavo A; Autschbach, Jochen

    2015-12-01

    NMR spectroscopic parameters of the proton involved in hydrogen bonding are studied theoretically. The set of molecules includes systems with internal resonance-assisted hydrogen bonds, internal hydrogen bonds but no resonance stabilization, the acetic acid dimer (AAD), a DNA base pair, and the hydrogen succinate anion (HSA). Ethanol and guanine represent reference molecules without hydrogen bonding. The calculations are based on zero-point vibrationally averaged molecular structures in order to include anharmonicity effects in the NMR parameters. An analysis of the calculated NMR shielding and J-coupling is performed in terms of "chemist's orbitals", that is, localized molecular orbitals (LMOs) representing lone-pairs, atomic cores, and bonds. The LMO analysis associates some of the strong de-shielding of the protons in resonance-assisted hydrogen bonds with delocalization involving the π-backbone. Resonance is also shown to be an important factor causing de-shielding of the OH protons for AAD and HSA, but not for the DNA base pair. Nitromalonamide (NMA) and HSA have particularly strong hydrogen bonds exhibiting signs of covalency in the associated J-couplings. The analysis results show how NMR spectroscopic parameters that are characteristic for hydrogen bonded protons are influenced by the geometry and degree of covalency of the hydrogen bond as well as intra- and intermolecular resonance.

  15. Analysis of Radiation Induced Degradation in FPC-461 Fluoropolymers by Variable Temperature Multinuclear NMR

    SciTech Connect

    Chinn, S C; Wilson, T S; Maxwell, R S

    2004-10-27

    Solid state nuclear magnetic resonance techniques have been used to investigate aging mechanisms in a vinyl chloride:chlorotrifluoroethylene copolymer, FPC-461, due to exposure to {gamma}-radiation. Solid state {sup 1}H MAS NMR spectra revealed structural changes of the polymer upon irradiation under both air and nitrogen atmospheres. Considerable degradation is seen with {sup 1}H NMR in the vinyl chloride region of the polymer, particularly in the samples irradiated in air. {sup 19}F MAS NMR was used to investigate speciation in the chlorotrifluoroethylene blocks, though negligible changes were seen. {sup 1}H and {sup 19}F NMR at elevated temperature revealed increased segmental mobility and decreased structural heterogeneity within the polymer, yielding significant resolution enhancement over room temperature solid state detection. The effects of multi-site exchange are manifest in both the {sup 1}H and {sup 19}F NMR spectra as a line broadening and change in peak position as a function of temperature.

  16. 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

  17. Extraction of alkaloids for NMR-based profiling: exploratory analysis of an archaic Cinchona bark collection.

    PubMed

    Yilmaz, Ali; Nyberg, Nils T; Jaroszewski, Jerzy W

    2012-11-01

    A museum collection of Cinchonae cortex samples (n = 117), from the period 1850-1950, was extracted with a mixture of chloroform-d1, methanol-d4, water-d2, and perchloric acid in the ratios 5 : 5 : 1 : 1. The extracts were directly analyzed using 1H NMR spectroscopy (600 MHz) and the spectra evaluated using principal component analysis (PCA) and total statistical correlation spectroscopy (STOCSY). A new method called STOCSY-CA, where CA stands for component analysis, is described, and an analysis using this method is presented. It was found that the samples had a rather homogenous content of the well-known cinchona alkaloids quinine, cinchonine, and cinchonidine without any apparent clustering. Signals from analogues were detected but not in substantial amounts. The main variation was related to the absolute amounts of extracted alkaloids, which was attributed to the evolution of the Cinchona tree cultivation during the period in which the samples were collected.

  18. Multinuclear Solid-State NMR and DFT Studies on Phosphanido-Bridged Diplatinum Complexes.

    PubMed

    Mastrorilli, Piero; Todisco, Stefano; Bagno, Alessandro; Gallo, Vito; Latronico, Mario; Fortuño, Consuelo; Gudat, Dietrich

    2015-06-15

    Multinuclear ((31)P, (195)Pt, (19)F) solid-state NMR experiments on (nBu4N)2[(C6F5)2Pt(μ-PPh2)2Pt(C6F5)2] (1), [(C6F5)2Pt(μ-PPh2)2Pt(C6F5)2](Pt-Pt) (2), and cis-Pt(C6F5)2(PHPh2)2 (3) were carried out under cross-polarization/magic-angle-spinning conditions or with the cross-polarization/Carr-Purcell Meiboom-Gill pulse sequence. Analysis of the principal components of the (31)P and (195)Pt chemical shift (CS) tensors of 1 and 2 reveals that the variations observed comparing the isotropic chemical shifts of 1 and 2, commonly referred to as "ring effect", are mainly due to changes in the principal components oriented along the direction perpendicular to the Pt2P2 plane. DFT calculations of (31)P and (195)Pt CS tensors confirmed the tensor orientation proposed from experimental data and symmetry arguments and revealed that the different values of the isotropic shieldings stem from differences in the paramagnetic and spin-orbit contributions.

  19. 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. PMID:27343582

  20. A comparison of 31P magnetic resonance spectroscopy and microbubble-enhanced ultrasound for characterizing hepatitis c-related liver disease.

    PubMed

    Lim, A K P; Patel, N; Eckersley, R J; Fitzpatrick, J; Crossey, M M E; Hamilton, G; Goldin, R D; Thomas, H C; Vennart, W; Cosgrove, D O; Taylor-Robinson, S D

    2011-10-01

    We compared in vivo hepatic (31) P magnetic resonance spectroscopy ((31) P MRS) and hepatic vein transit times (HVTT) using contrast-enhanced ultrasound with a microbubble agent to assess the severity of hepatitis C virus (HCV)-related liver disease. Forty-six patients with biopsy-proven HCV-related liver disease and nine healthy volunteers had (31) P MRS and HVTT performed on the same day. (31) P MR spectra were obtained at 1.5 T. Peak areas were calculated for metabolites, including phosphomonoesters (PME) and phosphodiesters (PDE). Patients also had the microbubble ultrasound contrast agent, Levovist (2 g), injected into an antecubital vein, and time-intensity Doppler ultrasound signals of the right and middle hepatic veins were measured. The HVTT was calculated as the time from injection to a sustained rise in Doppler signal 10% greater than baseline. The shortest times were used for analysis. Based on Ishak histological scoring, there were 15 patients with mild hepatitis, 20 with moderate/severe hepatitis and 11 with cirrhosis. With increasing severity of disease, the PME/PDE ratio was steadily elevated, while the HVTT showed a monotonic decrease. Both imaging modalities could separate patients with cirrhosis from the mild and moderate/severe hepatitis groups. No statistical difference was observed in the accuracy of each test to denote mild, moderate/severe hepatitis and cirrhosis (Fisher's exact test P =1.00). (31) P MRS and HVTT show much promise as noninvasive imaging tests for assessing the severity of chronic liver disease. Both are equally effective and highly sensitive in detecting cirrhosis.

  1. General order parameter based correlation analysis of protein backbone motions between experimental NMR relaxation measurements and molecular dynamics simulations.

    PubMed

    Liu, Qing; Shi, Chaowei; Yu, Lu; Zhang, Longhua; Xiong, Ying; Tian, Changlin

    2015-02-13

    Internal backbone dynamic motions are essential for different protein functions and occur on a wide range of time scales, from femtoseconds to seconds. Molecular dynamic (MD) simulations and nuclear magnetic resonance (NMR) spin relaxation measurements are valuable tools to gain access to fast (nanosecond) internal motions. However, there exist few reports on correlation analysis between MD and NMR relaxation data. Here, backbone relaxation measurements of (15)N-labeled SH3 (Src homology 3) domain proteins in aqueous buffer were used to generate general order parameters (S(2)) using a model-free approach. Simultaneously, 80 ns MD simulations of SH3 domain proteins in a defined hydrated box at neutral pH were conducted and the general order parameters (S(2)) were derived from the MD trajectory. Correlation analysis using the Gromos force field indicated that S(2) values from NMR relaxation measurements and MD simulations were significantly different. MD simulations were performed on models with different charge states for three histidine residues, and with different water models, which were SPC (simple point charge) water model and SPC/E (extended simple point charge) water model. S(2) parameters from MD simulations with charges for all three histidines and with the SPC/E water model correlated well with S(2) calculated from the experimental NMR relaxation measurements, in a site-specific manner.

  2. Interaction of epicatechin gallate with phospholipid membranes as revealed by solid-state NMR spectroscopy.

    PubMed

    Uekusa, Yoshinori; Kamihira-Ishijima, Miya; Sugimoto, Osamu; Ishii, Takeshi; Kumazawa, Shigenori; Nakamura, Kozo; Tanji, Ken-ichi; Naito, Akira; Nakayama, Tsutomu

    2011-06-01

    Epicatechin gallate (ECg), a green tea polyphenol, has various physiological effects. Our previous nuclear Overhauser effect spectroscopy (NOESY) study using solution NMR spectroscopy demonstrated that ECg strongly interacts with the surface of phospholipid bilayers. However, the dynamic behavior of ECg in the phospholipid bilayers has not been clarified, especially the dynamics and molecular arrangement of the galloyl moiety, which supposedly has an important interactive role. In this study, we synthesized [13C]-ECg, in which the carbonyl carbon of the galloyl moiety was labeled by 13C isotope, and analyzed it by solid-state NMR spectroscopy. Solid-state 31P NMR analysis indicated that ECg changes the gel-to-liquid-crystalline phase transition temperature of DMPC bilayers as well as the dynamics and mobility of the phospholipids. In the solid-state 13C NMR analysis under static conditions, the carbonyl carbon signal of the [13C]-ECg exhibited an axially symmetric powder pattern. This indicates that the ECg molecules rotate about an axis tilting at a constant angle to the bilayer normal. The accurate intermolecular-interatomic distance between the labeled carbonyl carbon of [13C]-ECg and the phosphorus of the phospholipid was determined to be 5.3±0.1 Å by 13C-(31)P rotational echo double resonance (REDOR) measurements. These results suggest that the galloyl moiety contributes to increasing the hydrophobicity of catechin molecules, and consequently to high affinity of galloyl-type catechins for phospholipid membranes, as well as to stabilization of catechin molecules in the phospholipid membranes by cation-π interaction between the galloyl ring and quaternary amine of the phospholipid head-group. PMID:21352801

  3. General order parameter based correlation analysis of protein backbone motions between experimental NMR relaxation measurements and molecular dynamics simulations

    SciTech Connect

    Liu, Qing; Shi, Chaowei; Yu, Lu; Zhang, Longhua; Xiong, Ying; Tian, Changlin

    2015-02-13

    Internal backbone dynamic motions are essential for different protein functions and occur on a wide range of time scales, from femtoseconds to seconds. Molecular dynamic (MD) simulations and nuclear magnetic resonance (NMR) spin relaxation measurements are valuable tools to gain access to fast (nanosecond) internal motions. However, there exist few reports on correlation analysis between MD and NMR relaxation data. Here, backbone relaxation measurements of {sup 15}N-labeled SH3 (Src homology 3) domain proteins in aqueous buffer were used to generate general order parameters (S{sup 2}) using a model-free approach. Simultaneously, 80 ns MD simulations of SH3 domain proteins in a defined hydrated box at neutral pH were conducted and the general order parameters (S{sup 2}) were derived from the MD trajectory. Correlation analysis using the Gromos force field indicated that S{sup 2} values from NMR relaxation measurements and MD simulations were significantly different. MD simulations were performed on models with different charge states for three histidine residues, and with different water models, which were SPC (simple point charge) water model and SPC/E (extended simple point charge) water model. S{sup 2} parameters from MD simulations with charges for all three histidines and with the SPC/E water model correlated well with S{sup 2} calculated from the experimental NMR relaxation measurements, in a site-specific manner. - Highlights: • Correlation analysis between NMR relaxation measurements and MD simulations. • General order parameter (S{sup 2}) as common reference between the two methods. • Different protein dynamics with different Histidine charge states in neutral pH. • Different protein dynamics with different water models.

  4. Ab Initio Calculation of Nuclear Magnetic Resonance Chemical Shift Anisotropy Tensors 1. Influence of Basis Set on the Calculation of 31P Chemical Shifts

    SciTech Connect

    Alam, T.M.

    1998-09-01

    The influence of changes in the contracted Gaussian basis set used for ab initio calculations of nuclear magnetic resonance (NMR) phosphorous chemical shift anisotropy (CSA) tensors was investigated. The isotropic chemical shitl and chemical shift anisotropy were found to converge with increasing complexity of the basis set at the Hartree-Fock @IF) level. The addition of d polarization function on the phosphorous nucIei was found to have a major impact of the calculated chemical shi~ but diminished with increasing number of polarization fimctions. At least 2 d polarization fimctions are required for accurate calculations of the isotropic phosphorous chemical shift. The introduction of density fictional theory (DFT) techniques through tie use of hybrid B3LYP methods for the calculation of the phosphorous chemical shift tensor resulted in a poorer estimation of the NMR values, even though DFT techniques result in improved energy and force constant calculations. The convergence of the W parametem with increasing basis set complexity was also observed for the DFT calculations, but produced results with consistent large deviations from experiment. The use of a HF 6-31 l++G(242p) basis set represents a good compromise between accuracy of the simulation and the complexity of the calculation for future ab initio calculations of 31P NMR parameters in larger complexes.

  5. Conformational analysis of 2,6-diarylpiperidin-4-one hydrazones by X-ray diffraction and NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Sankar, C.; Umamatheswari, S.; Pandiarajan, K.

    2015-03-01

    A new series of 3t-alkyl-2r,6c-diarylpiperidin-4-one N-isonicotinoylhydrazones (12-22) derived from the condensation of 3t-alkyl-2r,6c-diarylpiperidin-4-ones with isoniazid (INH) is reported. Newly synthesized compounds have been characterized by using elemental analysis, IR, 1H, 13C and 2D NMR spectral analysis. Moreover, representative crystal structure of 3,3-dimethyl-2r,6c-diarylpiperidin-4-one N-isonicotinoylhydrazone has been determined by X-ray diffraction analysis. NMR data revealed that two geometrical isomers (E and Z) are formed in all cases, and the piperidine ring adopts chair conformation. Whereas in solid state the compounds have E configuration about the Cdbnd N bond. These conclusions have also been confirmed by X-ray data of compound 16.

  6. Excitation functions for actinides produced in the interactions of sup 31 P with sup 248 Cm

    SciTech Connect

    Leyba, J.D.; Henderson, R.A.; Hall, H.L.; Czerwinski, K.R.; Kadkhodayan, B.A.; Kreek, S.A.; Brady, E.K.; Gregorich, K.E.; Lee, D.M.; Nurmia, M.J.; Hoffman, D.C. Nuclear Science Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California )

    1991-11-01

    Excitation functions have been measured for the production of various isotopes of Bk, Cf, Es, and Fm from the interactions of 174- and 239-MeV {sup 31}P projectiles with {sup 248}Cm. The isotopic distributions were symmetric and displayed full widths at half maximum of 2.5, 2.5, and 2.25 mass units for Bk, Cf, and Fm, respectively. The maxima of the isotopic distributions occur for those reaction channels which involve the exchange of the fewest number of nucleons between the target and projectile for which the calculated excitation energy is a positive quantity. The maxima of the excitation functions occur at those projectile energies which are consistent with the calculated reaction barriers based upon a binary reaction mechanism. The effects of the odd proton in the {sup 31}P projectile on the final isotopic distributions are discussed.

  7. PFG-NMR analysis of intercompartment exchange and inner droplet size distribution of W/O/W emulsions.

    PubMed

    Hindmarsh, Jason P; Su, Jiahong; Flanagan, John; Singh, Harjinder

    2005-09-27

    Presented is a novel application of pulsed field gradient (PFG)-NMR to the analysis of intercompartment exchange and the inner compartment droplet size distribution of a W/O/W multiple emulsion. The method involves monitoring the diffusional behavior of different components of the emulsion. Pfeuffer et al. [Pfeuffer, J.; Flogel, U.; Dreher, W.; Leibfritz, D. NMR Biomed. 1998, 11(1), 19-31.](1) and Price et al. [Price, W. S.; Barzykin, A. V.; Hayamizu, K.; Tachiya, M. Biophys. J. 1998, 74(5), 2259-2271.](2) proposed methods to extend Kärger's PFG-NMR model of exchange between two compartments to accommodate spherical inner compartments. Each model enables the prediction of the oil membrane permeability, the inner compartment volume fraction, and a representation of the inner compartment droplet size distribution. The models were fitted to PFG-NMR experimental data of W/O/W emulsions. The Pfeuffer et al. model provided the best description of the observed experimental data. Predicted values of permeability and swelling were consistent with those reported in the literature for W/O/W emulsions. The addition of sorbitol to either the inner or outer water compartment resulted in an increase in the oil membrane permeability. Inner compartment droplet size distribution measurements indicate that swelling, rupture, and coalescence are likely to have occurred during the secondary emulsification and emulsion ripening. In its present form, the method still constitutes a fast, noninvasive (no addition of a tracer), and in situ method for comparative analysis of the permeability, stability, and yield of different formulations of multiple emulsions with a single PFG-NMR experiment. PMID:16171335

  8. Recommendations and Standardization of Biomarker Quantification Using NMR-Based Metabolomics with Particular Focus on Urinary Analysis

    PubMed Central

    2016-01-01

    NMR-based metabolomics has shown considerable promise in disease diagnosis and biomarker discovery because it allows one to nondestructively identify and quantify large numbers of novel metabolite biomarkers in both biofluids and tissues. Precise metabolite quantification is a prerequisite to move any chemical biomarker or biomarker panel from the lab to the clinic. Among the biofluids commonly used for disease diagnosis and prognosis, urine has several advantages. It is abundant, sterile, and easily obtained, needs little sample preparation, and does not require invasive medical procedures for collection. Furthermore, urine captures and concentrates many “unwanted” or “undesirable” compounds throughout the body, providing a rich source of potentially useful disease biomarkers; however, incredible variation in urine chemical concentrations makes analysis of urine and identification of useful urinary biomarkers by NMR challenging. We discuss a number of the most significant issues regarding NMR-based urinary metabolomics with specific emphasis on metabolite quantification for disease biomarker applications and propose data collection and instrumental recommendations regarding NMR pulse sequences, acceptable acquisition parameter ranges, relaxation effects on quantitation, proper handling of instrumental differences, sample preparation, and biomarker assessment. PMID:26745651

  9. A NMR-Based Carbon-Type Analysis of Diesel Fuel Blends From Various Sources

    SciTech Connect

    Bays, J. Timothy; King, David L.

    2013-05-10

    In collaboration with participants of the Coordinating Research Council (CRC) Advanced Vehicle/Fuels/Lubricants (AVFL) Committee, and project AVFL-19, the characteristics of fuels from advanced and renewable sources were compared to commercial diesel fuels. The main objective of this study was to highlight similarities and differences among the fuel types, i.e. ULSD, renewables, and alternative fuels, and among fuels within the different fuel types. This report summarizes the carbon-type analysis from 1H and 13C{1H} nuclear magnetic resonance spectroscopy (NMR) of 14 diesel fuel samples. The diesel fuel samples come from diverse sources and include four commercial ultra-low sulfur diesel fuels (ULSD), one gas-to-liquid diesel fuel (GTL), six renewable diesel fuels (RD), two shale oil-derived diesel fuels, and one oil sands-derived diesel fuel. Overall, the fuels examined fall into two groups. The two shale oil-derived samples and the oil-sand-derived sample closely resemble the four commercial ultra-low sulfur diesels, with SO1 and SO2 most closely matched with ULSD1, ULSD2, and ULSD4, and OS1 most closely matched with ULSD3. As might be expected, the renewable diesel fuels, with the exception of RD3, do not resemble the ULSD fuels because of their very low aromatic content, but more closely resemble the gas-to-liquid sample (GTL) in this respect. RD3 is significantly different from the other renewable diesel fuels in that the aromatic content more closely resembles the ULSD fuels. Fused-ring aromatics are readily observable in the ULSD, SO, and OS samples, as well as RD3, and are noticeably absent in the remaining RD and GTL fuels. Finally, ULSD3 differs from the other ULSD fuels by having a significantly lower aromatic carbon content and higher cycloparaffinic carbon content. In addition to providing important comparative compositional information regarding the various diesel fuels, this report also provides important information about the capabilities of NMR

  10. Revealing the metabonomic variation of rosemary extracts using 1H NMR spectroscopy and multivariate data analysis.

    PubMed

    Xiao, Chaoni; Dai, Hui; Liu, Hongbing; Wang, Yulan; Tang, Huiru

    2008-11-12

    The molecular compositions of rosemary ( Rosmarinus officinalis L.) extracts and their dependence on extraction solvents, seasons, and drying processes were systematically characterized using NMR spectroscopy and multivariate data analysis. The results showed that the rosemary metabonome was dominated by 33 metabolites including sugars, amino acids, organic acids, polyphenolic acids, and diterpenes, among which quinate, cis-4-glucosyloxycinnamic acid, and 3,4,5-trimethoxyphenylmethanol were found in rosemary for the first time. Compared with water extracts, the 50% aqueous methanol extracts contained higher levels of sucrose, succinate, fumarate, malonate, shikimate, and phenolic acids, but lower levels of fructose, glucose, citrate, and quinate. Chloroform/methanol was an excellent solvent for selective extraction of diterpenes. From February to August, the levels of rosmarinate and quinate increased, whereas the sucrose level decreased. The sun-dried samples contained higher concentrations of rosmarinate, sucrose, and some amino acids but lower concentrations of glucose, fructose, malate, succinate, lactate, and quinate than freeze-dried ones. These findings will fill the gap in the understanding of rosemary composition and its variations.

  11. High-resolution 2D NMR spectroscopy of bicelles to measure the membrane interaction of ligands.

    PubMed

    Dvinskikh, Sergey V; Dürr, Ulrich H N; Yamamoto, Kazutoshi; Ramamoorthy, Ayyalusamy

    2007-01-31

    Magnetically aligned bicelles are increasingly being used as model membranes in solution- and solid-state NMR studies of the structure, dynamics, topology, and interaction of membrane-associated peptides and proteins. These studies commonly utilize the PISEMA pulse sequence to measure dipolar coupling and chemical shift, the two key parameters used in subsequent structural analysis. In the present study, we demonstrate that the PISEMA and other rotating-frame pulse sequences are not suitable for the measurement of long-range heteronuclear dipolar couplings, and that they provide inaccurate values when multiple protons are coupled to a 13C nucleus. Furthermore, we demonstrate that a laboratory-frame separated-local-field experiment is capable of overcoming these difficulties in magnetically aligned bicelles. An extension of this approach to accurately measure 13C-31P and 1H-31P couplings from phospholipids, which are useful to understand the interaction of molecules with the membrane, is also described. In these 2D experiments, natural abundance 13C was observed from bicelles containing DMPC and DHPC lipid molecules. As a first application, these solid-state NMR approaches were utilized to probe the membrane interaction of an antidepressant molecule, desipramine, and its location in the membrane.

  12. Metabolite profiling of Curcuma species grown in different regions using 1H NMR spectroscopy and multivariate analysis.

    PubMed

    Jung, Youngae; Lee, Jueun; Kim, Ho Kyoung; Moon, Byeong Cheol; Ji, Yunui; Ryu, Do Hyun; Hwang, Geum-Sook

    2012-12-01

    Curcuma is used to treat skin diseases and colic inflammatory disorders, and in insect repellants and antimicrobial and antidiabetic medications. Two Curcuma species (C. aromatica and C. longa) grown in Jeju-do and Jin-do were used in this study. Methanolic extracts were analyzed by (1)H NMR spectroscopy, and metabolite profiling coupled with multivariate analysis was applied to characterize the differences between species or origin. PCA analysis showed significantly greater differences between species than origins, and the metabolites responsible for the differences were identified. The concentrations of sugars (glucose, fructose, and sucrose) and essential oils (eucalyptol, curdione, and germacrone) were significantly different between the two species. However, the samples from Jeju-do and Jin-do were different mainly in their concentrations of organic acids (fumarate, succinate, acetate, and formate) and sugars. This study demonstrates that NMR-based metabolomics is an efficient method for fingerprinting and determining differences between Curcuma species or those grown in different regions.

  13. An advanced NMR protocol for the structural characterization of aluminophosphate glasses.

    PubMed

    van Wüllen, Leo; Tricot, Grégory; Wegner, Sebastian

    2007-10-01

    In this work a combination of complementary advanced solid-state nuclear magnetic resonance (NMR) strategies is employed to analyse the network organization in aluminophosphate glasses to an unprecedented level of detailed insight. The combined results from MAS, MQMAS and (31)P-{(27)Al}-CP-heteronuclear correlation spectroscopy (HETCOR) NMR experiments allow for a detailed speciation of the different phosphate and aluminate species present in the glass. The interconnection of these local building units to an extended three-dimensional network is explored employing heteronuclear dipolar and scalar NMR approaches to quantify P-O-Al connectivity by (31)P{(27)Al}-heteronuclear multiple quantum coherence (HMQC), -rotational echo adiabatic passage double resonance (REAPDOR) and -HETCOR NMR as well as (27)Al{(31)P}-rotational echo double resonance (REDOR) NMR experiments, complemented by (31)P-2D-J-RESolved MAS NMR experiments to probe P-O-P connectivity utilizing the through bond scalar J-coupling. The combination of the results from the various NMR approaches enables us to not only quantify the phosphate units present in the glass but also to identify their respective structural environments within the three-dimensional network on a medium length scale employing a modified Q notation, Q(n)(m),(AlO)(x), where n denotes the number of connected tetrahedral phosphate, m gives the number of aluminate species connected to a central phosphate unit and x specifies the nature of the bonded aluminate species (i.e. 4, 5 or 6 coordinate aluminium).

  14. Dietary fat modulation of mammary tumor growth and metabolism demonstrated by /sup 31/P-nuclear magnetic resonance

    SciTech Connect

    Erickson, K.L.; Buckman, D.K.; Hubbard, N.E.; Ross, B.

    1986-03-05

    The relationship of dietary fat concentration and saturation on the growth and metabolic activity of line 168 was studied using syngeneic mice fed 6 experimental diets before and during tumor growth. Tumor latency was significantly greater for mice fed a diet containing the minimum of essential fatty acids (EFA, 0.5% corn oil) or 8% coconut oil (SF) than for mice fed 8 or 20% safflower oil (PUF) or 20% SF. Changes in dietary fat resulted in alterations of tumor cell and serum fatty acid composition but not the number of inflammatory cells infiltrating the tumor. /sup 31/P-surface coil NMR was used to measure possible changes in tumor metabolism in vivo. Although pH decreased from 7.2 to 6.6 as the tumor volume increased, there was no difference in pH among dietary groups. There was an inverse relationship between both sugar phosphate (SP)/Pi and ATP/Pi ratios and tumor volume; those ratios for mice fed an EFA deficient or minimal EFA diet decreased at a different rate than ratios for mice fed diets with additional fat. Tumors of mice fed diets containing no or a low level (0.3%) of 18:2 had higher SP/ATP ratios than mice fed diets containing a moderate level (approx. 4%) of 18:2. Thus, high levels of dietary fat had a significant effect on promotion of mammary tumors during early stages of tumor growth. Differences in tumor volume associated with dietary fat may be related to changes in the levels of high energy phosphate metabolites.

  15. Cation substitution in β-tricalcium phosphate investigated using multi-nuclear, solid-state NMR

    NASA Astrophysics Data System (ADS)

    Grigg, Andrew T.; Mee, Martin; Mallinson, Phillip M.; Fong, Shirley K.; Gan, Zhehong; Dupree, Ray; Holland, Diane

    2014-04-01

    The substitution of aluminium, gallium and sodium cations into β-tricalcium phosphate (β-TCP; Ca3(PO4)2) has been investigated, and the Ca sites involved successfully determined, using a combination of 1D 31P, 27Al, 71Ga, 23Na and 43Ca (natural abundance) NMR and 2D 27Al{31P}, 71Ga{31P} and 23Na{31P} rotary-resonance-recoupled heteronuclear multiple-quantum correlation (R3-HMQC) NMR. Over the compositional range studied, substitution of Ca2+ by Al3+ or Ga3+ was observed only on the Ca(5) site, whilst substitution by Na+ was confined to the Ca(4) site. Some AlPO4 or GaPO4 second phase was observed at the highest doping levels in the Al3+ and Ga3+ substituted samples.

  16. Effect of molecular exchange on water droplet size analysis in W/O emulsions as determined by diffusion NMR.

    PubMed

    Vermeir, Lien; Sabatino, Paolo; Balcaen, Mathieu; Declerck, Arnout; Dewettinck, Koen; Martins, José C; Van der Meeren, Paul

    2016-02-01

    Using NMR diffusometry, the diffusion of water and tetramethylammonium chloride was recorded in order to determine the water droplet size distribution in W/O emulsions. This study aimed at evaluating the effect of extradroplet diffusion of water on the estimated droplet size distribution upon comparison to the real droplet size distribution. The latter originated from the diffusion behavior of the tetramethylammonium cation (TMA+), which is known to have a much lower permeability through the oil phase as compared to water. Whereas both low-resolution and high-resolution pulsed field gradient NMR revealed that the water droplet size overestimation could be reduced selecting either a lower measurement temperature during diffusion analysis, or a smaller diffusion delay value Δ, still comparison to TMA+ diffusion indicated that artefacts were unavoidable even at low Δ and temperature. In order to correct for this extradroplet water diffusion phenomenon, different data analysis methods were evaluated. The previously described Pfeuffer exchange model could only partly compensate for the effect of extradroplet diffusion on the water droplet size determination. On the other hand, accurate water droplet size analysis results were obtained by correcting the experimentally determined diffusion distances based on Einstein's diffusion law. As such, reliable data could be obtained by low resolution NMR based on water diffusion at or even above room temperature. PMID:26520819

  17. Independent component analysis (ICA) algorithms for improved spectral deconvolution of overlapped signals in 1H NMR analysis: application to foods and related products.

    PubMed

    Monakhova, Yulia B; Tsikin, Alexey M; Kuballa, Thomas; Lachenmeier, Dirk W; Mushtakova, Svetlana P

    2014-05-01

    The major challenge facing NMR spectroscopic mixture analysis is the overlapping of signals and the arising impossibility to easily recover the structures for identification of the individual components and to integrate separated signals for quantification. In this paper, various independent component analysis (ICA) algorithms [mutual information least dependent component analysis (MILCA); stochastic non-negative ICA (SNICA); joint approximate diagonalization of eigenmatrices (JADE); and robust, accurate, direct ICA algorithm (RADICAL)] as well as deconvolution methods [simple-to-use-interactive self-modeling mixture analysis (SIMPLISMA) and multivariate curve resolution-alternating least squares (MCR-ALS)] are applied for simultaneous (1)H NMR spectroscopic determination of organic substances in complex mixtures. Among others, we studied constituents of the following matrices: honey, soft drinks, and liquids used in electronic cigarettes. Good quality spectral resolution of up to eight-component mixtures was achieved (correlation coefficients between resolved and experimental spectra were not less than 0.90). In general, the relative errors in the recovered concentrations were below 12%. SIMPLISMA and MILCA algorithms were found to be preferable for NMR spectra deconvolution and showed similar performance. The proposed method was used for analysis of authentic samples. The resolved ICA concentrations match well with the results of reference gas chromatography-mass spectrometry as well as the MCR-ALS algorithm used for comparison. ICA deconvolution considerably improves the application range of direct NMR spectroscopy for analysis of complex mixtures.

  18. Characterization of solid polymer dispersions of active pharmaceutical ingredients by 19F MAS NMR and factor analysis

    NASA Astrophysics Data System (ADS)

    Urbanova, Martina; Brus, Jiri; Sedenkova, Ivana; Policianova, Olivia; Kobera, Libor

    In this contribution the ability of 19F MAS NMR spectroscopy to probe structural variability of poorly water-soluble drugs formulated as solid dispersions in polymer matrices is discussed. The application potentiality of the proposed approach is demonstrated on a moderately sized active pharmaceutical ingredient (API, Atorvastatin) exhibiting extensive polymorphism. In this respect, a range of model systems with the API incorporated in the matrix of polvinylpyrrolidone (PVP) was prepared. The extent of mixing of both components was determined by T1(1H) and T1ρ(1H) relaxation experiments, and it was found that the API forms nanosized domains. Subsequently it was found out that the polymer matrix induces two kinds of changes in 19F MAS NMR spectra. At first, this is a high-frequency shift reaching 2-3 ppm which is independent on molecular structure of the API and which results from the long-range polarization of the electron cloud around 19F nucleus induced by electrostatic fields of the polymer matrix. At second, this is broadening of the signals and formation of shoulders reflecting changes in molecular arrangement of the API. To avoid misleading in the interpretation of the recorded 19F MAS NMR spectra, because both the contributions act simultaneously, we applied chemometric approach based on multivariate analysis. It is demonstrated that factor analysis of the recorded spectra can separate both these spectral contributions, and the subtle structural differences in the molecular arrangement of the API in the nanosized domains can be traced. In this way 19F MAS NMR spectra of both pure APIs and APIs in solid dispersions can be directly compared. The proposed strategy thus provides a powerful tool for the analysis of new formulations of fluorinated pharmaceutical substances in polymer matrices.

  19. sup 31 P nuclear magnetic resonance study of the effect of azide on xylose fermentation by Candida tropicalis

    SciTech Connect

    Lohmeier-Vogel, E.; Vogel, H. ); Skoog, K.; Hahn-Haegerdal, B. )

    1989-08-01

    Maximal ethanol production by Candida tropicalis grown on xylose was obtained at an oxygen transfer rate of 5 to 7 mmol/liter per h. Addition of 0.2 mM azide increased the ethanol yield by a factor of 3 to 4, based on the cell mass produced, and decreased the formation of the by-product xylitol by 80%. In the presence of azide, ethanol was reassimilated before the carbon source was depleted. At all oxygenation levels studied, azide caused 25 to 60% of the carbon to be lost, most probable as carbon dioxide. Identical spectra were obtained with {sup 31}P nuclear magnetic resonance spectroscopy performed on extracts of C. tropicalis grown on xylose in the absence and presence of azide. Azide lowered the levels of sugar phosphates. Enzymatic analysis showed extremely low levels of fructose 1,6-diphosphate compared with the levels obtained in the absence of azide, while the level of malate, a citric acid cycle intermediate, was not influenced by azide. {sup 31}P nuclear magnetic resonance spectroscopy performed on xylose-grown whole cells of C. tropicalis showed that azide lowered the intracellular pH, inhibited the uptake of external P{sub i}, and decreased the buildup of polyphosphate in relation to results with untreated cells. Similar results were obtained with the uncoupler of oxidative phosphorylation carbonyl cyanide m-chlorophenylhydrazone (CCCP), except that CCCP treatment led to extremely high levels of internal P{sub i}. The dual effect of azide as a respiratory inhibitor and as an uncoupler is discussed with respect to the metabolism and product formation in xylose-assimilating C. tropicalis.

  20. 31P nuclear magnetic resonance study of the effect of azide on xylose fermentation by Candida tropicalis.

    PubMed Central

    Lohmeier-Vogel, E; Skoog, K; Vogel, H; Hahn-Hägerdal, B

    1989-01-01

    Maximal ethanol production by Candida tropicalis grown on xylose was obtained at an oxygen transfer rate of 5 to 7 mmol/liter per h. Addition of 0.2 mM azide increased the ethanol yield by a factor of 3 to 4, based on the cell mass produced, and decreased the formation of the by-product xylitol by 80%. In the presence of azide, ethanol was reassimilated before the carbon source was depleted. At all oxygenation levels studied, azide caused 25 to 60% of the carbon to be lost, most probably as carbon dioxide. Identical spectra were obtained with 31P nuclear magnetic resonance spectroscopy performed on extracts of C. tropicalis grown on xylose in the absence and presence of azide. Azide lowered the levels of sugar phosphates. Enzymatic analysis showed extremely low levels of fructose 1,6-diphosphate compared with the levels obtained in the absence of azide, while the level of malate, a citric acid cycle intermediate, was not influenced by azide. 31P nuclear magnetic resonance spectroscopy performed on xylose-grown whole cells of C. tropicalis showed that azide lowered the intracellular pH, inhibited the uptake of external Pi, and decreased the buildup of polyphosphate in relation to results with untreated cells. Similar results were obtained with the uncoupler of oxidative phosphorylation carbonyl cyanide m-chlorophenylhydrazone (CCCP), except that CCCP treatment led to extremely high levels of internal Pi. The dual effect of azide as a respiratory inhibitor and as an uncoupler is discussed with respect to the metabolism and product formation in xylose-assimilating C. tropicalis. PMID:2782875

  1. Double and zero quantum filtered 2H NMR analysis of D2O in intervertebral disc tissue

    NASA Astrophysics Data System (ADS)

    Ooms, Kristopher J.; Vega, Alexander J.; Polenova, Tatyana; Cannella, Marco; Marcolongo, Michele

    2015-09-01

    The analysis of double and zero quantum filtered 2H NMR spectra obtained from D2O perfused in the nucleus pulposus of human intervertebral disc tissue samples is reported. Fitting the spectra with a three-site model allows for residual quadrupolar couplings and T2 relaxation times to be measured. The analysis reveals changes in both the couplings and relaxation times as the tissue begins to show signs of degradation. The full analysis demonstrates that information about tissue hydration, water collagen interactions, and sample heterogeneity can be obtained and used to better understand the biochemical differences between healthy and degraded tissue.

  2. Hetero Diels-Alder Reaction with Aqueous Glyoxylic Acid: An Experiment in Organic Synthesis and 2-D NMR Analysis for Advanced Undergraduate Students

    NASA Astrophysics Data System (ADS)

    Augé, Jacques; Lubin-Germain, Nadège

    1998-10-01

    As an application of the use of water as solvent in organic synthesis, a convenient synthesis of a-hydroxy-g-lactones from an aqueous solution of glyoxylic acid is described. The mechanism of the reaction leading to the lactones goes through cycloadducts which rearrange in situ. The NMR analysis of the diastereomeric lactones is particularly interesting; such an analysis illustrates the importance of modern techniques including 2-D NMR spectroscopy. Complete assignments of the signals are mentioned and NOESY spectra are enclosed. The full experiment is addressed to advanced undergraduate students who are trained in organic synthesis and NMR spectroscopy.

  3. Characteristics and degradation of carbon and phosphorus from aquatic macrophytes in lakes: insights from solid-state 13C NMR and solution 31P NMR spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  4. (1)H and DOSY NMR spectroscopy analysis of Ligusticum porteri rhizome extracts.

    PubMed

    León, Alejandra; Chávez, María Isabel; Delgado, Guillermo

    2011-08-01

    The presence of dimeric phthalides and other constituents in extracts of the vegetal species Ligusticum porteri was established by NMR spectroscopy. In comparative qualitative (1)H NMR analyses of acetone extracts of rhizomes from fresh and dried L. porteri samples, we found that the dimeric phthalides tokinolide B (3), diligustilide (4) and riligustilide (5) were naturally produced by the plant and not post-harvest products. We also obtained DOSY (1)H NMR data that provided both virtual separation and structural information for the phthalides present in a dry acetone extract of L. porteri. In addition, we developed a protocol for the quantification of dimeric phthalides, which is performed by calculating the relative ratio of the peak area of selected proton signals for some compounds with respect to the known signal of the internal standard, 4-dimethylaminopyridine. The protocol allows the rapid and direct quantification of dimeric phthalides and others constituents in fresh L. porteri rhizomes. PMID:21761449

  5. Inhibition of thermolysin by phosphonamidate transition-state analogues: measurement of 31P-15N bond lengths and chemical shifts in two enzyme-inhibitor complexes by solid-state nuclear magnetic resonance.

    PubMed

    Copié, V; Kolbert, A C; Drewry, D H; Bartlett, P A; Oas, T G; Griffin, R G

    1990-10-01

    31P and 15N chemical shifts and 31P-15N bond lengths have been measured with solid-state NMR techniques in two inhibitors of thermolysin, carbobenzoxy-Glyp-L-Leu-L-Ala (ZGpLA) and carbobenzoxy-L-Phep-L-Leu-L-Ala (ZFpLA), both as free lithium salts and when bound to the enzyme. Binding of both inhibitors to thermolysin results in large changes in the 31P chemical shifts. These changes are more dramatic for the tighter binding inhibitor ZFpLA, where a approximately 20 ppm downfield movement of the 31P isotropic chemical shift (sigma iso) is observed. This shift is due to changes in the shift tensor elements sigma 11 and sigma 22, while sigma 33 remains essentially constant. We observed a similar pattern for ZGpLA, but only a approximately 5 ppm change occurs in sigma iso. The changes in the 15N chemical shifts for both inhibitors are small upon binding, amounting to downfield shifts of 2 and 4 ppm for ZGpLA and ZFpLA, respectively. This indicates that there are no changes in the protonation state of the 15N in either the ZFpLA- or the ZGpLA-thermolysin complex. NMR distance measurements yield a P-N bond length rP-N = 1.68 +/- 0.03 A for the tight binding inhibitor ZFpLA both in its free lithium salt form and in its thermolysin-ZFpLA complex, a distance that is much shorter than the 1.90-A distance reported by X-ray crystallography studies [Holden et al. (1987) Biochemistry 26, 8542-8553].(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2271586

  6. Inhibition of thermolysin by phosphonamidate transition-state analogues: measurement of 31P-15N bond lengths and chemical shifts in two enzyme-inhibitor complexes by solid-state nuclear magnetic resonance.

    PubMed

    Copié, V; Kolbert, A C; Drewry, D H; Bartlett, P A; Oas, T G; Griffin, R G

    1990-10-01

    31P and 15N chemical shifts and 31P-15N bond lengths have been measured with solid-state NMR techniques in two inhibitors of thermolysin, carbobenzoxy-Glyp-L-Leu-L-Ala (ZGpLA) and carbobenzoxy-L-Phep-L-Leu-L-Ala (ZFpLA), both as free lithium salts and when bound to the enzyme. Binding of both inhibitors to thermolysin results in large changes in the 31P chemical shifts. These changes are more dramatic for the tighter binding inhibitor ZFpLA, where a approximately 20 ppm downfield movement of the 31P isotropic chemical shift (sigma iso) is observed. This shift is due to changes in the shift tensor elements sigma 11 and sigma 22, while sigma 33 remains essentially constant. We observed a similar pattern for ZGpLA, but only a approximately 5 ppm change occurs in sigma iso. The changes in the 15N chemical shifts for both inhibitors are small upon binding, amounting to downfield shifts of 2 and 4 ppm for ZGpLA and ZFpLA, respectively. This indicates that there are no changes in the protonation state of the 15N in either the ZFpLA- or the ZGpLA-thermolysin complex. NMR distance measurements yield a P-N bond length rP-N = 1.68 +/- 0.03 A for the tight binding inhibitor ZFpLA both in its free lithium salt form and in its thermolysin-ZFpLA complex, a distance that is much shorter than the 1.90-A distance reported by X-ray crystallography studies [Holden et al. (1987) Biochemistry 26, 8542-8553].(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Interaction evaluation of silver and dithizone complexes using DFT calculations and NMR analysis.

    PubMed

    Wasukan, Nootcharin; Srisung, Sujittra; Kuno, Mayuso; Kulthong, Kornphimol; Maniratanachote, Rawiwan

    2015-10-01

    Silver has distinct antibacterial properties and has been used as a component of commercial products with many applications. An increasing number of commercial products cause risks of silver effects for human and environment such as the symptoms of Argyria and the release of silver to the environment. Therefore, the detection of silver in the aquatic environment is important. The colorimetric chemosensor is designed by the basic of ligand interactions with metal ion, leading to the change of signals for the naked-eyes which is very useful method to this application. Dithizone ligand is considered as one of the effective chelating reagents for metal ions due to its high selectivity and sensitivity of a photochromic reaction for silver as well as the linear backbone of dithizone affords the rotation of various isomeric forms. The present study is focused on the conformation and interaction of dithizone with silver using density functional theory (DFT). The interaction parameters were determined in term of binding energy of complexes and the geometry optimization, frequency of the structures and calculation of binding energies using density functional approaches B3LYP and the 6-31G(d,p) basis set. Moreover, the interaction of silver-dithizone complexes was supported by UV-Vis spectroscopy, FT-IR spectrum that were simulated by using B3LYP/6-31G(d,p) and (1)H NMR spectra calculation using B3LYP/6-311+G(2d,p) method compared with the experimental data. The results showed the ion exchange interaction between hydrogen of dithizone and silver atom with minimized binding energies of silver-dithizone interaction. Therefore, the results can be the useful information for determination of complex interaction using the analysis of computer simulations. PMID:26001102

  8. 13C solid-state NMR chemical shift anisotropy analysis of the anomeric carbon in carbohydrates.

    PubMed

    Chen, Ying-Ying; Luo, Shun-Yuan; Hung, Shang-Cheng; Chan, Sunney I; Tzou, Der-Lii M

    2005-03-21

    (13)C NMR solid-state structural analysis of the anomeric center in carbohydrates was performed on six monosaccharides: glucose (Glc), mannose (Man), galactose (Gal), galactosamine hydrochloride (GalN), glucosamine hydrochloride (GlcN), and N-acetyl-glucosamine (GlcNAc). In the 1D (13)C cross-polarization/magic-angle spinning (CP/MAS) spectrum, the anomeric center C-1 of these carbohydrates revealed two well resolved resonances shifted by 3-5ppm, which were readily assigned to the anomeric alpha and beta forms. From this experiment, we also extracted the (13)C chemical shift anisotropy (CSA) tensor elements of the two forms from their spinning sideband intensities, respectively. It was found out that the chemical shift tensor for the alpha anomer was more axially symmetrical than that of the beta form. A strong linear correlation was obtained when the ratio of the axial asymmetry of the (13)C chemical shift tensors of the two anomeric forms was plotted in a semilogarithmic plot against the relative population of the two anomers. Finally, we applied REDOR spectroscopy to discern whether or not there were any differences in the sugar ring conformation between the anomers. Identical two-bond distances of 2.57A (2.48A) were deduced for both the alpha and beta forms in GlcNAc (GlcN), suggesting that the two anomers have essentially identical sugar ring scaffolds in these sugars. In light of these REDOR distance measurements and the strong correlation observed between the ratio of the axial asymmetry parameters of the (13)C chemical shift tensors and the relative population between the two anomeric forms, we concluded that the anomeric effect arises principally from interaction of the electron charge clouds between the C-1-O-5 and the C-1-O-1 bonds in these monosaccharides.

  9. A Quantitative NMR Analysis of Phosphorus in Carbonaceous and Ordinary Chondrites

    NASA Technical Reports Server (NTRS)

    Pasek, M. A.; Smith, V. D.; Lauretta, D. S.

    2004-01-01

    Phosphorus is important in a number of biochemical molecules, from DNA to ATP. Early life may have depended on meteorites as a primary source of phosphorus as simple dissolution of crustal apatite may not produce the necessary concentration of phosphate. Phosphorus is found in several mineral phases in meteorites. Apatite and other Ca- and Mg phosphate minerals tend to be the dominant phosphorus reservoir in stony meteorites, whereas in more iron-rich or reduced meteorites, the phosphide minerals schreibersite, (Fe, Ni)3P, and perryite, (Ni, Fe)5(Si, P)2 are dominant. However, in CM chondrites that have experienced significant aqueous alteration, phosphorus has been detected in more exotic molecules. A series of phosphonic acids including methyl-, ethyl-, propyl- and butyl- phosphonic acids were observed by GC-MS in Murchison. Phosphorian sulfides are in Murchison and Murray. NMR spectrometry is capable of detecting multiple substances with one experiment, is non-destructive, and potentially quantitative, as discussed below. Despite these advantages, NMR spectrometry is infrequently applied to meteoritic studies due in large part to a lack of applicability to many compounds and the relatively high limit of detection requirements. Carbon-13 solid-state NMR has been applied to macromolecular carbon in Murchison. P-31 NMR has many advantages over aqueous carbon-13 NMR spectrometry. P-31 is the only isotope of phosphorus, and P-31 gives a signal approximately twice as strong as C-13. These two factors together with the relative abundances of carbon and phosphorus imply that phosphorus should give a signal approximately 20 as strong as carbon in a given sample. A discussion on the preparation of the quantitative standard and NMR studies are presented

  10. a Combined Molecular Dynamics and NMR Spectroscopic Protocol for the Conformational Analysis of Oligosaccharides.

    NASA Astrophysics Data System (ADS)

    Varma, Vikram

    A combined experimental and theoretical protocol for the conformational analysis of oligosaccharides is presented. Three disaccharides, methyl alpha - scD-mannopyranosyl-(1 to 3)-alpha- scD-mannopyranoside, methyl beta- scD-galactopyranosyl-(1 to 4)-beta- scD-glucopyranoside, and propyl beta- scD-2-acetamido -2-deoxy glucopyranosyl-(1 to 3)- alpha- scL-rhamnopyranoside, are used to evaluate a protocol for conformational analysis that makes use of molecular dynamics calculations with the CHARMM force field. Dynamics trajectories computed in vacuo and in water are used to calculate time-averaged NMR parameters such as spin-lattice relaxation times (T_1 ), Nuclear Overhauser Enhancements (NOE), and heteronuclear spin-spin coupling constants (^3J _{rm CH}). The calculated NMR parameters are then compared to experimental values and used to evaluate the computational procedure. The energetically accessible conformations are effectively sampled by the simulations. The method has been extended to the conformational analysis of higher-order oligosaccharides corresponding to the cell-wall polysaccharide of the Streptococcus Group A, and the Shigella flexneri Y O-antigen. The Streptococcus Group A cell-wall polysaccharide is comprised of a backbone of rhamnopyranosyl units connected by alternating alpha- scL-(1 to 3) and alpha- scL -(1 to 2) linkages, to which are attached N-acetyl-beta- scD-glucosamine ( beta- scD-GlcpNAc) residues at the 3 positions of the rhamnose backbone.rm A&rm B^'qquad A^'& rm Bqquad Acr[{-alpha}{-}L{-}Rha {it p}{-}(1to2){-alpha }{-}L{-}Rha{it p} {-}(1to3){-alpha}{ -}L{-}Rha{it p}-(1to2) -alpha-L-Rha{it p}{-}(1 to3){-alpha}{-}L{- }Rha{it p}{-}cr&uparrow(1 to3)&uparrow(1to3)crbeta {-}D{-}&rm Glc{it p }NAcqquadbeta{-}D{-}& rm Glc{it p}NAccr&rm C ^'&rm C] A branched trisaccharide (A^' -(C)B), a tetrasaccharide (A^' -(C)B-A), a pentasaccharide (C^' -B^'-A ^'-(C)B), and two hexasaccharides (C^'-B^ '-A^' -(C)B-A) and (A-(C^')B ^'-A^' -(C)B), have been chosen

  11. Apparatus for preparing a solution of a hyperpolarized noble gas for NMR and MRI analysis

    DOEpatents

    Pines, Alexander; Budinger, Thomas; Navon, Gil; Song, Yi-Qiao; Appelt, Stephan; Bifone, Angelo; Taylor, Rebecca; Goodson, Boyd; Seydoux, Roberto; Room, Toomas; Pietrass, Tanja

    2008-06-10

    The present invention relates generally to nuclear magnetic resonance (NMR) techniques for both spectroscopy and imaging. More particularly, the present invention relates to methods in which hyperpolarized noble gases (e.g., Xe and He) are used to enhance and improve NMR and MRI. Additionally, the hyperpolarized gas solutions of the invention are useful both in vitro and in vivo to study the dynamics or structure of a system. When used with biological systems, either in vivo or in vitro, it is within the scope of the invention to target the hyperpolarized gas and deliver it to specific regions within the system.

  12. Fourier transform C-13 NMR analysis of some free and potassium-ion complexed antibiotics.

    NASA Technical Reports Server (NTRS)

    Ohnishi, M.; Fedarko, M.-C.; Baldeschwieler, J. D.; Johnson, L. F.

    1972-01-01

    Fourier transforms of the noise-decoupled, natural abundance C-13 NMR free induction decays of the cyclic antibiotic valinomycin and its potassium-ion complex have been obtained at 25.2 MHz. Comparisons are made with C-13 NMR spectra taken at 22.6 MHz of the cyclic antibiotic nonactin and the synthetic polyether dicyclohexyl-18-crown-6 and their potassium complexes. The results obtained suggest that conformational rearrangements of the molecule as a whole can compete with direct interactions between carbons and the potassium ion in determining C-13 chemical shift differences between the free and complexed species.

  13. Transient states in [2 + 2] photodimerization of cinnamic acid: correlation of solid-state NMR and X-ray analysis.

    PubMed

    Khan, Mujeeb; Brunklaus, Gunther; Enkelmann, Volker; Spiess, Hans-Wolfgang

    2008-02-01

    13C-CPMAS and other solid-state NMR methods have been applied to monitor the solid-state reactions of trans-cinnamic acid derivatives, which are the pioneer and model compounds in the field of topochemistry previously studied by X-ray diffraction, AFM, and vibrational spectroscopy. Single-crystal X-ray analyses of photoirradiated alpha-trans-cinnamic acid where the monomers are arranged in a head-to-tail manner have revealed the formation of a centrosymmetric alpha-truxillic acid photodimer. For a centrosymmetric dimer, however, two cyclobutane carbon signals and one carbonyl carbon signal were expected apart from other aromatic carbon signals. Instead, four cyclobutane and two carbonyl carbon signals were observed suggesting the formation of a non-centrosymmetric photodimer. Removing hydrogen bonds from the system by esterfication of alpha-truxillic acid yield a centrosymmetric photodimer. Careful analysis of the obtained products via solid-state NMR clearly showed that the observed peak splittings in the 13C-CPMAS spectra did not originate from packing effects but rather result from asymmetric hydrogen bonds distorting the local symmetry. Further evidence of this rather dynamic hydrogen-bonding stems from high-temperature X-ray data revealing that only the joint approach of both X-ray analysis and solid-state NMR at similar temperatures allows for the successful characterization of dynamic processes occurring in topochemical reactions, thus, providing detailed insight into the reaction mechanism of organic solid-state transformations.

  14. Combining Hydrophilic Interaction Chromatography (HILIC) and Isotope Tagging for Off-Line LC-NMR Applications in Metabolite Analysis

    PubMed Central

    Appiah-Amponsah, Emmanuel; Owusu-Sarfo, Kwadwo; Gowda, G.A. Nagana; Ye, Tao; Raftery, Daniel

    2013-01-01

    The complementary use of liquid chromatography (LC) and nuclear magnetic resonance (NMR) has shown high utility in a variety of fields. While the significant benefit of spectral simplification can be achieved for the analysis of complex samples, other limitations remain. For example, 1H LC-NMR suffers from pH dependent chemical shift variations, especially during urine analysis, owing to the high physiological variation of urine pH. Additionally, large solvent signals from the mobile phase in LC can obscure lower intensity signals and severely limit the number of metabolites detected. These limitations, along with sample dilution, hinder the ability to make reliable chemical shift assignments. Recently, stable isotopic labeling has been used to detect quantitatively specific classes of metabolites of interest in biofluids. Here we present a strategy that explores the combined use of two-dimensional hydrophilic interaction chromatography (HILIC) and isotope tagged NMR for the unambiguous identification of carboxyl containing metabolites present in human urine. The ability to separate structurally related compounds chromatographically, in off-line mode, followed by detection using 1H-15N 2D HSQC (two-dimensional heteronuclear single quantum coherence) spectroscopy, resulted in the assignment of low concentration carboxyl-containing metabolites from a library of isotope labeled compounds. The quantitative nature of this strategy is also demonstrated. PMID:24860727

  15. 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.

  16. The use of IRMS, (1)H NMR and chemical analysis to characterise Italian and imported Tunisian olive oils.

    PubMed

    Camin, Federica; Pavone, Anita; Bontempo, Luana; Wehrens, Ron; Paolini, Mauro; Faberi, Angelo; Marianella, Rosa Maria; Capitani, Donatella; Vista, Silvia; Mannina, Luisa

    2016-04-01

    Isotope Ratio Mass Spectrometry (IRMS), (1)H Nuclear Magnetic Resonance ((1)H NMR), conventional chemical analysis and chemometric elaboration were used to assess quality and to define and confirm the geographical origin of 177 Italian PDO (Protected Denomination of Origin) olive oils and 86 samples imported from Tunisia. Italian olive oils were richer in squalene and unsaturated fatty acids, whereas Tunisian olive oils showed higher δ(18)O, δ(2)H, linoleic acid, saturated fatty acids β-sitosterol, sn-1 and 3 diglyceride values. Furthermore, all the Tunisian samples imported were of poor quality, with a K232 and/or acidity values above the limits established for extra virgin olive oils. By combining isotopic composition with (1)H NMR data using a multivariate statistical approach, a statistical model able to discriminate olive oil from Italy and those imported from Tunisia was obtained, with an optimal differentiation ability arriving at around 98%.

  17. Optimized (31)P MRS in the human brain at 7 T with a dedicated RF coil setup.

    PubMed

    van de Bank, Bart L; Orzada, Stephan; Smits, Frits; Lagemaat, Miriam W; Rodgers, Christopher T; Bitz, Andreas K; Scheenen, Tom W J

    2015-11-01

    The design and construction of a dedicated RF coil setup for human brain imaging ((1)H) and spectroscopy ((31)P) at ultra-high magnetic field strength (7 T) is presented. The setup is optimized for signal handling at the resonance frequencies for (1)H (297.2 MHz) and (31)P (120.3 MHz). It consists of an eight-channel (1)H transmit-receive head coil with multi-transmit capabilities, and an insertable, actively detunable (31)P birdcage (transmit-receive and transmit only), which can be combined with a seven-channel receive-only (31)P array. The setup enables anatomical imaging and (31)P studies without removal of the coil or the patient. By separating transmit and receive channels and by optimized addition of array signals with whitened singular value decomposition we can obtain a sevenfold increase in SNR of (31)P signals in the occipital lobe of the human brain compared with the birdcage alone. These signals can be further enhanced by 30 ± 9% using the nuclear Overhauser effect by B1-shimmed low-power irradiation of water protons. Together, these features enable acquisition of (31)P MRSI at high spatial resolutions (3.0 cm(3)  voxel) in the occipital lobe of the human brain in clinically acceptable scan times (~15 min). PMID:26492089

  18. HPLC analysis of ecdysteroids in plant extracts using superheated deuterium oxide with multiple on-line spectroscopic analysis (UV, IR, 1H NMR, and MS).

    PubMed

    Louden, Dave; Handley, Alan; Lafont, Rene; Taylor, Steve; Sinclair, Ian; Lenz, Eva; Orton, Timothy; Wilson, Ian D

    2002-01-01

    HPLC, using superheated D20 as the mobile phase, combined with on-line characterization via a combination of diode array UV, 1H NMR, FT-IR spectroscopy, and mass spectrometry has been used for the analysis of a standard of 20-hydroxyecdysone- and ecdysteroid-containing plant extracts. This combination of spectrometers enabled the on-flow collection of UV, 1H NMR, IR, and mass spectra not only for pure 20-hydroxyecdysone (100-400 microg on column) but also the major ecdysteroids present in crude extracts of Silene otites, Silene nutans, and Silene frivaldiskyana. The ecdysteroids unequivocally identified in these extracts included 20-hydroxyecdysone, polypodine B, and integristerone A.

  19. NMR studies on polyphosphide Ce6Ni6P17

    NASA Astrophysics Data System (ADS)

    Koyama, T.; Yamada, H.; Ueda, K.; Mito, T.; Aoyama, Y.; Nakano, T.; Takeda, N.

    2016-02-01

    We report the result of 31P nuclear magnetic resonance (NMR) studies on Ce6Ni6P17. The observed NMR spectra show a Lorentzian-type and an asymmetric shapes, reflecting the local symmetry around each P site in the cubic unit cell. We have identified the observed NMR lines corresponding to three inequivalent P sites and deduced the temperature dependence of the Knight shift for each site. The Knight shifts increase with decreasing temperature down to 1.5 K, indicating a localized spin system of Ce6Ni6P17. Antiferromagnetic correlation between 4f spins is suggested from the negative sign of the Weiss-temperature.

  20. NMR analysis and tacticity determination of poly(lactic acid) in C5D5N

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this work tacticity assignments of poly(lactic acid), (PLA), are reported for the NMR peaks from CH carbon and CH3 proton at the tetrad level in deuterated pyridine. The methyl protons are better resolved in pyridine due to solvent effects such as ring current shielding of the aromatic ring and ...

  1. Genetic analysis of 16 NMR-lipoprotein fractions in humans, the GOLDN study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sixteen nuclear magnetic resonance (NMR) spectroscopy lipoprotein measurements of more than 1,000 subjects of GOLDN study, at fasting and at 3.5 and 6 h after a postprandial fat (PPL) challenge at visits 2 and 4, before and after a 3 weeks Fenofibrate (FF) treatment, were included in 6 time-independ...

  2. ¹³C solid-state NMR analysis of the most common pharmaceutical excipients used in solid drug formulations Part II: CP kinetics and relaxation analysis.

    PubMed

    Pisklak, Dariusz Maciej; Zielińska-Pisklak, Monika; Szeleszczuk, Łukasz; Wawer, Iwona

    2016-04-15

    Excipients used in the solid drug formulations differ in their NMR relaxation and (13)C cross-polarization (CP) kinetics parameters. Therefore, experimental parameters like contact time of cross-polarization and repetition time have a major impact on the registered solid state NMR spectra and in consequence on the results of the NMR analysis. In this work the CP kinetics and relaxation of the most common pharmaceutical excipients: anhydrous α-lactose, α-lactose monohydrate, mannitol, sucrose, sorbitol, sodium starch glycolate type A and B, starch of different origin, microcrystalline cellulose, hypromellose, ethylcellulose, methylcellulose, hydroxyethylcellulose, sodium alginate, magnesium stearate, sodium laurilsulfate and Kollidon(®) were analyzed. The studied excipients differ significantly in their optimum repetition time (from 5 s to 1200 s) and T(1ρ)(I) parameters (from 2 ms to 73 ms). The practical use of those differences in the excipients composition analysis was demonstrated on the example of commercially available tablets containing indapamide as an API. The information presented in this article will help to choose the correct acquisition parameters and also will save the time and effort needed for their optimization in the NMR analysis of the solid drug formulations.

  3. ¹³C solid-state NMR analysis of the most common pharmaceutical excipients used in solid drug formulations Part II: CP kinetics and relaxation analysis.

    PubMed

    Pisklak, Dariusz Maciej; Zielińska-Pisklak, Monika; Szeleszczuk, Łukasz; Wawer, Iwona

    2016-04-15

    Excipients used in the solid drug formulations differ in their NMR relaxation and (13)C cross-polarization (CP) kinetics parameters. Therefore, experimental parameters like contact time of cross-polarization and repetition time have a major impact on the registered solid state NMR spectra and in consequence on the results of the NMR analysis. In this work the CP kinetics and relaxation of the most common pharmaceutical excipients: anhydrous α-lactose, α-lactose monohydrate, mannitol, sucrose, sorbitol, sodium starch glycolate type A and B, starch of different origin, microcrystalline cellulose, hypromellose, ethylcellulose, methylcellulose, hydroxyethylcellulose, sodium alginate, magnesium stearate, sodium laurilsulfate and Kollidon(®) were analyzed. The studied excipients differ significantly in their optimum repetition time (from 5 s to 1200 s) and T(1ρ)(I) parameters (from 2 ms to 73 ms). The practical use of those differences in the excipients composition analysis was demonstrated on the example of commercially available tablets containing indapamide as an API. The information presented in this article will help to choose the correct acquisition parameters and also will save the time and effort needed for their optimization in the NMR analysis of the solid drug formulations. PMID:26836362

  4. Determination of the illicit drug gamma-hydroxybutyrate (GHB) in human saliva and beverages by 1H NMR analysis.

    PubMed

    Grootveld, Martin; Algeo, Deborah; Silwood, Christopher J L; Blackburn, John C; Clark, Anthony D

    2006-01-01

    High resolution 1H NMR spectroscopy has been employed to investigate the detection and quantification of the illicit "date-rape" drug gamma-hydroxybutyrate (GHB) in both human saliva and a commonly-consumed low-alcohol beer product. Data acquired revealed that this multicomponent analytical technique provided unequivocal evidence for the detection of this agent by this technique in both of these matrices, i.e., all three of its resonances [those ascribable to the alpha-CH2 (t, delta=2.25 ppm), beta-CH2 (tt, delta=1.81 ppm) and gamma-CH2 (t, delta=3.61 ppm) group protons] were present in spectra acquired on human saliva, and two of these (the alpha- and beta-CH2 group signals) in the beverage product examined, the latter observation attributable to overlap of the gamma-CH2 1H resonance with those of carbohydrates. Since good linear calibration relationships between the intensities of each of the NMR-visible signals and added GHB concentration (the former normalised to that of an external 3-trimethylsilyl [2,2,3,3-2H4]- propionate standard present in a coaxial NMR tube insert) were observed, this illicit drug is also readily quantifiable in such multicomponent samples. Our data demonstrate the advantages offered by this technique when applied to the analysis of illicit drugs in multicomponent sample matrices such as human biofluids and beverage products. PMID:17012769

  5. Solid-state NMR spectroscopy as a tool supporting optimization of MALDI-TOF MS analysis of polylactides.

    PubMed

    Sroka-Bartnicka, Anna; Olejniczak, Sebastian; Sochacki, Marek; Biela, Tadeusz; Potrzebowski, Marek J

    2009-01-01

    We report systematic structural studies of poly(l-lactide) (PLLA) employing matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and solid-state NMR spectroscopy. (13)C cross polarization magic angle spinning (CP/MAS) NMR data for 1,8-dihydroxy-9-anthracenone (DT), 2,5-dihydroxybenzoic acid (DHB), 2-(4-hydroxyphenylazo)-benzoic acid (HABA), and trans-3-indoleacrylic acid (IAA), four matrices commonly used in MALDI-TOF analysis of polymers, were analyzed to test the influence of crystallization conditions (solvent, inorganic salt) on sample morphology. (13)C principal elements of chemical shift tensor (CST) and line-shape analyses were employed to study of the nature of hydrogen bonding and to evaluate the crystallinity and amorphicity of the pure polymer. NMR parameters for PLLA were compared with data for polylactide crystallized with the four matrices under different conditions with the addition of two inorganic salts as cationization agents. This study revealed that the semicrystalline structure of the polymer does not change when it is embedded in the matrix. PMID:18926725

  6. How Bonding in Manganous Phosphates Affects their Mn(II)-(31)P Hyperfine Interactions.

    PubMed

    Un, Sun; Bruch, Eduardo M

    2015-11-01

    Manganous phosphates have been postulated to play an important role in cells as antioxidants. In situ Mn(II) electron-nuclear double resonance (ENDOR) spectroscopy has been used to measure their speciation in cells. The analyses of such ENDOR spectra and the quantification of cellular Mn(II) phosphates has been based on comparisons to in vitro model complexes and heuristic modeling. In order to put such analyses on a more physical and theoretical footing, the Mn(II)-(31)P hyperfine interactions of various Mn(II) phosphate complexes have been measured by 95 GHz ENDOR spectroscopy. The dipolar components of these interactions remained relatively constant as a function of pH, esterification, and phosphate chain length, while the isotropic contributions were significantly affected. Counterintuitively, although the manganese-phosphate bonds are weakened by protonation and esterification, they lead to larger isotropic values, indicating higher unpaired-electron spin densities at the phosphorus nuclei. By comparison, extending the phosphate chain with additional phosphate groups lowers the spin density. Density functional theory calculations of model complexes quantitatively reproduced the measured hyperfine couplings and provided detailed insights into how bonding in Mn(II) phosphate complexes modulates the electron-spin polarization and consequently their isotropic hyperfine couplings. These results show that various classes of phosphates can be identified by their ENDOR spectra and provide a theoretical framework for understanding the in situ (31)P ENDOR spectra of cellular Mn(II) complexes.

  7. How Bonding in Manganous Phosphates Affects their Mn(II)-(31)P Hyperfine Interactions.

    PubMed

    Un, Sun; Bruch, Eduardo M

    2015-11-01

    Manganous phosphates have been postulated to play an important role in cells as antioxidants. In situ Mn(II) electron-nuclear double resonance (ENDOR) spectroscopy has been used to measure their speciation in cells. The analyses of such ENDOR spectra and the quantification of cellular Mn(II) phosphates has been based on comparisons to in vitro model complexes and heuristic modeling. In order to put such analyses on a more physical and theoretical footing, the Mn(II)-(31)P hyperfine interactions of various Mn(II) phosphate complexes have been measured by 95 GHz ENDOR spectroscopy. The dipolar components of these interactions remained relatively constant as a function of pH, esterification, and phosphate chain length, while the isotropic contributions were significantly affected. Counterintuitively, although the manganese-phosphate bonds are weakened by protonation and esterification, they lead to larger isotropic values, indicating higher unpaired-electron spin densities at the phosphorus nuclei. By comparison, extending the phosphate chain with additional phosphate groups lowers the spin density. Density functional theory calculations of model complexes quantitatively reproduced the measured hyperfine couplings and provided detailed insights into how bonding in Mn(II) phosphate complexes modulates the electron-spin polarization and consequently their isotropic hyperfine couplings. These results show that various classes of phosphates can be identified by their ENDOR spectra and provide a theoretical framework for understanding the in situ (31)P ENDOR spectra of cellular Mn(II) complexes. PMID:26488236

  8. NMR-based metabonomic analysis of the hepatotoxicity induced by combined exposure to PCBs and TCDD in rats

    SciTech Connect

    Lu Chunfeng; Wang Yimei; Sheng Zhiguo; Liu Gang; Fu Ze; Zhao Jing; Zhao Jun; Yan Xianzhong; Zhu Benzhan; Peng Shuangqing

    2010-11-01

    A metabonomic approach using {sup 1}H NMR spectroscopy was adopted to investigate the metabonomic pattern of rat urine after oral administration of environmental endocrine disruptors (EDs) polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) alone or in combination and to explore the possible hepatotoxic mechanisms of combined exposure to PCBs and TCDD. {sup 1}H NMR spectra of urines collected 24 h before and after exposure were analyzed via pattern recognition by using principal component analysis (PCA). Serum biochemistry and liver histopathology indicated significant hepatotoxicity in the rats of the combined group. The PCA scores plots of urinary {sup 1}H NMR data showed that all the treatment groups could be easily distinguished from the control group, so could the PCBs or TCDD group and the combined group. The loadings plots of the PCA revealed remarkable increases in the levels of lactate, glucose, taurine, creatine, and 2-hydroxy-isovaleric acid and reductions in the levels of 2-oxoglutarate, citrate, succinate, hippurate, and trimethylamine-N-oxide in rat urine after exposure. These changes were more striking in the combined group. The changed metabolites may be considered possible biomarker for the hepatotoxicity. The present study demonstrates that combined exposure to PCBs and TCDD induced significant hepatotoxicity in rats, and mitochondrial dysfunction and fatty acid metabolism perturbations might contribute to the hepatotoxicity. There was good conformity between changes in the urine metabonomic pattern and those in serum biochemistry and liver histopathology. These results showed that the NMR-based metabonomic approach may provide a promising technique for the evaluation of the combined toxicity of EDs.

  9. Singular spectrum analysis for an automated solvent artifact removal and baseline correction of 1D NMR spectra

    NASA Astrophysics Data System (ADS)

    De Sanctis, Silvia; Malloni, Wilhelm M.; Kremer, Werner; Tomé, Ana M.; Lang, Elmar W.; Neidig, Klaus-Peter.; Kalbitzer, Hans Robert

    2011-06-01

    NMR spectroscopy in biology and medicine is generally performed in aqueous solutions, thus in 1H NMR spectroscopy, the dominant signal often stems from the partly suppressed solvent and can be many orders of magnitude larger than the resonances of interest. Strong solvent signals lead to a disappearance of weak resonances of interest close to the solvent artifact and to base plane variations all over the spectrum. The AUREMOL-SSA/ALS approach for automated solvent artifact removal and baseline correction has been originally developed for multi-dimensional NMR spectroscopy. Here, we describe the necessary adaptations for an automated application to one-dimensional NMR spectra. Its core algorithm is still based on singular spectrum analysis (SSA) applied on time domain signals (FIDs) and it is still combined with an automated baseline correction (ALS) in the frequency domain. However, both steps (SSA and ALS) have been modified in order to achieve optimal results when dealing with one-dimensional spectra. The performance of the method has been tested on one-dimensional synthetic and experimental spectra including the back-calculated spectrum of HPr protein and an experimental spectrum of a human urine sample. The latter has been recorded with the typically used NOESY-type 1D pulse sequence including water pre-saturation. Furthermore, the fully automated AUREMOL-SSA/ALS procedure includes the managing of oversampled, digitally filtered and zero-filled data and the correction of the frequency domain phase shift caused by the group delay time shift from the digital finite response filtering.

  10. Multicomponent analysis of radiolytic products in human body fluids using high field proton nuclear magnetic resonance (NMR) spectroscopy

    NASA Astrophysics Data System (ADS)

    Grootveld, Martin C.; Herz, Herman; Haywood, Rachel; Hawkes, Geoffrey E.; Naughton, Declan; Perera, Anusha; Knappitt, Jacky; Blake, David R.; Claxson, Andrew W. D.

    1994-05-01

    High field proton Hahn spin-echo nuclear magnetic resonance (NMR) spectroscopy has been employed to investigate radiolytic damage to biomolecules present in intact human body fluids. γ-Radiolysis of healthy or rheumatoid human serum (5.00 kGy) in the presence of atmospheric O 2 gave rise to reproducible elevations in the concentration of NMR-detectable acetate which are predominantly ascribable to the prior oxidation of lactate to pyruvate by hydroxyl radical (·OH) followed by oxidative decarboxylation of pyruvate by radiolytically-generated hydrogen peroxide (H 2O 2) and/or further ·OH radical. Increases in the serum levels of non-protein-bound, low-molecular-mass components such as citrate and glutamine were also observed subsequent to γ-radiolysis, an observation which may reflect their mobilisation from protein binding-sites by ·OH radical, superoxide anion and/or H 2O 2. Moreover, substantial radiolytically-mediated elevations in the concentration of serum formate were also detectable. In addition to the above modifications, γ-radiolysis of inflammatory knee-joint synovial fluid (SF) generated a low-molecular-mass oligosaccharide species derived from the radiolytic fragmentation of hyaluronate. The radiolytically-mediated production of acetate in SF samples was markedly greater than that observed in serum samples, a consequence of the much higher levels of ·OH radical-scavenging lactate present. Indeed, increases in SF acetate concentration were detectable at doses as low as 48 Gy. We conclude that high field proton NMR analysis provides much useful information regarding the relative radioprotectant abilities of endogenous components and the nature, status and levels of radiolytic products generated in intact biofluids. We also suggest that NMR-detectable radiolytic products with associated toxicological properties (e.g. formate) may play a role in contributing to the deleterious effects observed following exposure of living organisms to sources of

  11. Reduced rate of adenosine triphosphate synthesis by in vivo 31P nuclear magnetic resonance spectroscopy and downregulation of PGC-1beta in distal skeletal muscle following burn.

    PubMed

    Tzika, A Aria; Mintzopoulos, Dionyssios; Padfield, Katie; Wilhelmy, Julie; Mindrinos, Michael N; Yu, Hongue; Cao, Haihui; Zhang, Qunhao; Astrakas, Loukas G; Zhang, Jiangwen; Yu, Yong-Ming; Rahme, Laurence G; Tompkins, Ronald G

    2008-02-01

    Using a mouse model of burn trauma, we tested the hypothesis that severe burn trauma corresponding to 30% of total body surface area (TBSA) causes reduction in adenosine triphosphate (ATP) synthesis in distal skeletal muscle. We employed in vivo 31P nuclear magnetic resonance (NMR) in intact mice to assess the rate of ATP synthesis, and characterized the concomitant gene expression patterns in skeletal muscle in burned (30% TBSA) versus control mice. Our NMR results showed a significantly reduced rate of ATP synthesis and were complemented by genomic results showing downregulation of the ATP synthase mitochondrial F1 F0 complex and PGC-1beta gene expression. Our findings suggest that inflammation and muscle atrophy in burns are due to a reduced ATP synthesis rate that may be regulated upstream by PGC-1beta. These findings implicate mitochondrial dysfunction in distal skeletal muscle following burn injury. That PGC-1beta is a highly inducible factor in most tissues and responds to common calcium and cyclic adenosine monophosphate (cAMP) signaling pathways strongly suggests that it may be possible to develop drugs that can induce PGC-1beta.

  12. NMR spectroscopic study of organic phosphate esters coprecipitated with calcite

    NASA Astrophysics Data System (ADS)

    Phillips, Brian L.; Zhang, Zelong; Kubista, Laura; Frisia, Silvia; Borsato, Andrea

    2016-06-01

    Organic phosphorus incorporated in calcite during laboratory precipitation experiments and in natural cave deposits was investigated by solid-state NMR spectroscopy. For calcite precipitated in the presence of organic phosphoesters of varying size and functionality, solid-state 31P{1H} CP/MAS NMR shows that the phosphoesters were incorporated intact into the solid. Systematic changes in the 31P NMR chemical shift of the phosphate group were observed between the solid phosphoester and that incorporated in the solid precipitate, yielding 31P NMR chemical shifts of the coprecipitates in the range of +1.8 to -2.2 ppm. These chemical shifts are distinct from that of similarly prepared calcite coprecipitated with inorganic phosphate, 3.5 ppm. Only minor changes were noted in the phosphoester 31P chemical shift anisotropy (CSA) which suggests no significant change in the local structure of the phosphate group, which is dominated by C-O-P bonding. Close spatial proximity of the organic phosphate group to calcite structural components was revealed by 31P/13C rotational echo double resonance (REDOR) experiments for coprecipitates prepared with 13C-labeled carbonate. All coprecipitates showed significant 31P dephasing effects upon 13C-irradiation, signaling atomic-scale proximity to carbonate carbon. The dephasing rate for smaller organophosphate molecules is similar to that observed for inorganic phosphate, whereas much slower dephasing was observed for larger molecules having long and/or bulky side-chains. This result suggests that small organic molecules can be tightly enclosed within the calcite structure, whereas significant structural disruption required to accommodate the larger organic molecules leads to longer phosphate-carbonate distances. Comparison of 31P NMR spectroscopic data from the synthetic coprecipitates with those from calcite moonmilk speleothems indicates that phosphorus occurs mainly as inorganic orthophosphate in the natural deposits, although small

  13. Temperature dependence of the 31P chemical shifts of nucleic acids. A prode of phosphate ester torsional conformations.

    PubMed

    Gorenstein, D G; Findlay, J B; Momii, R K; Luxon, B A; Kar, D

    1976-08-24

    The temperature dependence of the 31P chemical shifts of the ribodinucleoside monophosphates, ApA, GpC, CpC, UpU, and ApU, of the deoxyribonucleic acids, d-ApT, TpT, d-ApA, and d-pApT, and of the homopolyribonucleic acids poly(G), poly(U), poly(A) is shown to provide information on the helix-coli transition in nucleic acids. The base stacked, helical structure with a gauche,gauche phosphate ester torsional conformation is 0.2-0.6 ppm upfield from the random coil conformation. In contrast, the 31P chemical shifts of dimethyl and diethyl phosphate do not change significantly with temperature. These results support our earlier hypothesis that 31P shifts are sensitive probes of torsional conformations with phosphate esters in gauche,gauche conformations having 31P shifts upfield from nongauche conformations.

  14. NMR Properties of Platinum --Thallium Bonded Complexes. Analysis of Relativistic Density Functional Theory Results

    SciTech Connect

    LeGuennic, Boris; Matsumoto, Kazuko; Autschbach, Jochen

    2004-08-26

    A portion of the following research was conducted at EMSL. The metal NMR parameters of the complexes [(NC)5Pt–Tl(CN)n]n- (n = 0–3, I–IV) and [(NC)5Pt–Tl–Pt(CN)5]3- (V), as well as [fPt(NO3)(NH3)2L2gTl(NO3)2(MeOH)] (VI) and [fPt(NO3)(NH3)2L2g2Tl]+ (VII) with L =NHCOtBu,were computationally investigated by relativistic density functional theory. Complexes I–V were previously studied by us. We briefly review the main findings here. Their spin–spin coupling constants are analyzed in terms ofmolecular orbital and fragment orbital contributions which demonstrate the various influences of the solvent and of the ligands on the extraordinarily large metal–metal coupling constants. Complexes VI and VII and various model systems were investigated in more detail. It is shown that the same computational model which performs best for I–V yields too large metal–metal coupling constants for VI and VII. The analysis shows that this is likely to be attributable to a strong sensitivity of the coupling constants to the rather small Pt 6s contributions in the occupied metal–metal s-bonding orbitals. Bulk solvent effects on the metal–metal couplings are sizeable and should be considered in the computational model. Both calculated and experimental Pt–Tl coupling constants for VI and VII are substantially larger than those for I–V, thereby representing the largest heteronuclear coupling constants known so far experimentally. Metal chemical shifts for VI and VII were also investigated. The computational results indicate that the choice of the Pt reference is rather problematic. Tl chemical shifts agree much better with experimental data.

  15. MAS-NMR investigations of the crystallization behaviour of lithium aluminum silicate (LAS) glasses containing P{sub 2}O{sub 5} and TiO{sub 2} nucleants

    SciTech Connect

    Ananthanarayanan, A.; Kothiyal, G.P.; Montagne, L.; Revel, B.

    2010-06-15

    Lithium aluminum silicate (LAS) glass of composition (mol%) 20.4Li{sub 2}O-4.0Al{sub 2}O{sub 3}-68.6SiO{sub 2}-3.0K{sub 2}O-2.6B{sub 2}O{sub 3}-0.5P{sub 2}O{sub 5}-0.9TiO{sub 2} was prepared by melt quenching. The glass was then nucleated and crystallized based on differential thermal analysis (DTA) data and was characterized by {sup 29}Si, {sup 31}P, {sup 11}B and {sup 27}Al MAS-NMR. XRD and {sup 29}Si NMR showed that lithium metasilicate (Li{sub 2}SiO{sub 3}) is the first phase to c form followed by cristobalite (SiO{sub 2}) and lithium disilicate (Li{sub 2}Si{sub 2}O{sub 5}). {sup 29}Si MAS-NMR revealed a change in the network structure already for the glasses nucleated at 550 {sup o}C. Since crystalline Li{sub 3}PO{sub 4}, as observed by {sup 31}P MAS-NMR, forms concurrently with the silicate phases, we conclude that crystalline Li{sub 3}PO{sub 4} does not act as a nucleating agent for lithium silicate phases. Moreover, {sup 31}P NMR indicates the formation of M-PO{sub 4} (M=B, Al or Ti) complexes. The presence of BO{sub 3} and BO{sub 4} structural units in all the glass/glass-ceramic samples is revealed through {sup 11}B MAS-NMR. B remains in the residual glass and the crystallization of silicate phases causes a reduction in the number of alkali ions available for charge compensation. As a result, the number of trigonally coordinated B (BO{sub 3}) increases at the expense of tetrahedrally coordinated B (BO{sub 4}). The {sup 27}Al MAS-NMR spectra indicate the presence of tetrahedrally coordinated Al species, which are only slightly perturbed by the crystallization. - Graphical abstract: {sup 11}B MAS-NMR spectra of LAS glass heat treated at different temperatures, showing the evolution of the residual glass matrix during the crystallization treatment. High-field (18.8 T) NMR enables us to record high resolution spectra, from which the glass network modifications could be related to the formation of intermediate lithium silicate crystalline phases.

  16. A Global Approach to Accurate and Automatic Quantitative Analysis of NMR Spectra by Complex Least-Squares Curve Fitting

    NASA Astrophysics Data System (ADS)

    Martin, Y. L.

    The performance of quantitative analysis of 1D NMR spectra depends greatly on the choice of the NMR signal model. Complex least-squares analysis is well suited for optimizing the quantitative determination of spectra containing a limited number of signals (<30) obtained under satisfactory conditions of signal-to-noise ratio (>20). From a general point of view it is concluded, on the basis of mathematical considerations and numerical simulations, that, in the absence of truncation of the free-induction decay, complex least-squares curve fitting either in the time or in the frequency domain and linear-prediction methods are in fact nearly equivalent and give identical results. However, in the situation considered, complex least-squares analysis in the frequency domain is more flexible since it enables the quality of convergence to be appraised at every resonance position. An efficient data-processing strategy has been developed which makes use of an approximate conjugate-gradient algorithm. All spectral parameters (frequency, damping factors, amplitudes, phases, initial delay associated with intensity, and phase parameters of a baseline correction) are simultaneously managed in an integrated approach which is fully automatable. The behavior of the error as a function of the signal-to-noise ratio is theoretically estimated, and the influence of apodization is discussed. The least-squares curve fitting is theoretically proved to be the most accurate approach for quantitative analysis of 1D NMR data acquired with reasonable signal-to-noise ratio. The method enables complex spectral residuals to be sorted out. These residuals, which can be cumulated thanks to the possibility of correcting for frequency shifts and phase errors, extract systematic components, such as isotopic satellite lines, and characterize the shape and the intensity of the spectral distortion with respect to the Lorentzian model. This distortion is shown to be nearly independent of the chemical species

  17. Evaluation Of Automated Low-Field Nuclear Magnetic Resonance (NMR) Relaxometry For Analysis Of Silicone Polymers

    SciTech Connect

    M. H. Wilson

    2009-10-02

    Screening studies and Design of Experiments (DoE) were performed to evaluate measurement variation of a new, non-destructive Nuclear Magnetic Resonance (NMR) test system designed to assess age-induced degradation of Outer Pressure Pads (OPP). The test method and results from 54,275 measurements are described. A reduction in measurement error was obtained after metal support struts were replaced with plastic support struts adjacent to the front position of the test chamber. However, remaining interference and a lack of detecting any age-related degradation prevent the use of the NMR system as a non-destructive surveillance test for OPPs. A cursory evaluation of the system with cellular silicone samples obtained more uniform results with increased error as measurements approached the sample’s edge.

  18. Quantitative Analysis of Metabolic Mixtures by 2D 13C-Constant-Time TOCSY NMR Spectroscopy

    PubMed Central

    Bingol, Kerem; Zhang, Fengli; Bruschweiler-Li, Lei; Brüschweiler, Rafael

    2013-01-01

    An increasing number of organisms can be fully 13C-labeled, which has the advantage that their metabolomes can be studied by high-resolution 2D NMR 13C–13C constant-time (CT) TOCSY experiments. Individual metabolites can be identified via database searching or, in the case of novel compounds, through the reconstruction of their backbone-carbon topology. Determination of quantitative metabolite concentrations is another key task. Because significant peak overlaps in 1D NMR spectra prevents straightforward quantification through 1D peak integrals, we demonstrate here the direct use of 13C–13C CT-TOCSY spectra for metabolite quantification. This is accomplished through the quantum-mechanical treatment of the TOCSY magnetization transfer at short and long mixing times or by the use of analytical approximations, which are solely based on the knowledge of the carbon-backbone topologies. The methods are demonstrated for carbohydrate and amino-acid mixtures. PMID:23773204

  19. An instrument control and data analysis program for NMR imaging and spectroscopy

    SciTech Connect

    Roos, M.S.; Mushlin, R.A.; Veklerov, E.; Port, J.D.; Ladd, C.; Harrison, C.G.

    1988-01-01

    We describe a software environment created to support real-time instrument control and signal acquisition as well as array-processor based signal and image processing in up to five dimensions. The environment is configured for NMR imaging and in vivo spectroscopy. It is designed to provide flexible tools for implementing novel NMR experiments in the research laboratory. Data acquisition and processing operations are programmed in macros which are loaded in assembled from to minimize instruction overhead. Data arrays are dynamically allocated for efficient use of memory and can be mapped directly into disk files. The command set includes primitives for real-time control of data acquisition, scalar arithmetic, string manipulation, branching, a file system and vector operations carried out by an array processor. 6 figs.

  20. Advanced NMR-based techniques for pore structure analysis of coal. Final project report

    SciTech Connect

    Smith, D.M.; Hua, D.W.

    1996-02-01

    During the 3 year term of the project, new methods have been developed for characterizing the pore structure of porous materials such as coals, carbons, and amorphous silica gels. In general, these techniques revolve around; (1) combining multiple techniques such as small-angle x-ray scattering (SAXS) and adsorption of contrast-matched adsorbates or {sup 129}Xe NMR and thermoporometry (the change in freezing point with pore size), (2) combining adsorption isotherms over several pressure ranges to obtain a more complete description of pore filling, or (3) applying NMR ({sup 129}Xe, {sup 14}N{sub 2}, {sup 15}N{sub 2}) techniques with well-defined porous solids with pores in the large micropore size range (>1 nm).

  1. Operando NMR spectroscopic analysis of proton transfer in heterogeneous photocatalytic reactions

    PubMed Central

    Wang, Xue Lu; Liu, Wenqing; Yu, Yan-Yan; Song, Yanhong; Fang, Wen Qi; Wei, Daxiu; Gong, Xue-Qing; Yao, Ye-Feng; Yang, Hua Gui

    2016-01-01

    Proton transfer (PT) processes in solid–liquid phases play central roles throughout chemistry, biology and materials science. Identification of PT routes deep into the realistic catalytic process is experimentally challenging, thus leaving a gap in our understanding. Here we demonstrate an approach using operando nuclear magnetic resonance (NMR) spectroscopy that allows to quantitatively describe the complex species dynamics of generated H2/HD gases and liquid intermediates in pmol resolution during photocatalytic hydrogen evolution reaction (HER). In this system, the effective protons for HER are mainly from H2O, and CH3OH evidently serves as an outstanding sacrificial agent reacting with holes, further supported by our density functional theory calculations. This results rule out controversy about the complicated proton sources for HER. The operando NMR method provides a direct molecular-level insight with the methodology offering exciting possibilities for the quantitative studies of mechanisms of proton-involved catalytic reactions in solid–liquid phases. PMID:27311326

  2. Ultrafast double-quantum NMR spectroscopy with optimized sensitivity for the analysis of mixtures.

    PubMed

    Rouger, Laetitia; Gouilleux, Boris; Pourchet-Gellez, Mariane; Dumez, Jean-Nicolas; Giraudeau, Patrick

    2016-03-01

    Ultrafast (UF) 2D NMR enables the acquisition of 2D spectra within a single-scan. This methodology has become a powerful analytical tool, used in a large array of applications. However, UF NMR spectroscopy still suffers from the need to compromise between sensitivity, spectral width and resolution. With the commonly used UF-COSY pulse sequence, resolution issues are compounded by the presence of strong auto-correlation signals, particularly in the case of samples with high dynamic ranges. The recently proposed concept of UF Double Quantum Spectroscopy (DQS) allows a better peak separation as it provides a lower spectral peak density. This paper presents the detailed investigation of this new NMR tool in an analytical chemistry context. Theoretical calculations and numerical simulations are used to characterize the modulation of peak intensities as a function of pulse-sequence parameters, and thus enable a significant enhancement of the sensitivity. The analytical comparison of UF-COSY and UF-DQS shows similar performances, however the ultrafast implementation of the DQS approach is found to have some sensitivity advantages over its conventional counterpart. The analytical performance of the pulse sequence is illustrated by the quantification of taurine in complex mixtures (homemade and commercial energy drinks). The results demonstrate the high potential of this experiment, which forms a valuable alternative to UF-COSY spectra when the latter are characterized by strong overlaps and high dynamic ranges. PMID:26865359

  3. Analysis of SNARE complex/synaptotagmin-1 interactions by one-dimensional NMR spectroscopy.

    PubMed

    Zhou, Amy; Brewer, Kyle D; Rizo, Josep

    2013-05-21

    Neurotransmitter release depends critically on the Ca(2+) sensor synaptotagmin-1 and the SNARE proteins syntaxin-1, synaptobrevin, and SNAP-25, which mediate membrane fusion by forming tight SNARE complexes that bridge the synaptic vesicle and plasma membranes. Interactions between the SNARE complex and the two C2 domains of synaptotagmin-1 (the C2A and C2B domains) are believed to play a key role in coupling Ca(2+) sensing to membrane fusion, but the nature of these interactions is unclear, in part because of a paucity of data obtained by quantitative biophysical methods. Here we have analyzed synaptotagmin-1/SNARE complex interactions by monitoring the decrease in the intensities of one-dimensional (13)C-edited (1)H NMR spectra of (13)C-labeled fragments of synaptotagmin-1 upon binding to unlabeled SNARE complex. Our results indicate that there is a primary binding mode between synaptotagmin-1 and the SNARE complex that involves a polybasic region in the C2B domain and has a sub-micromolar affinity. Our NMR data, combined with precipitation assays, show that there are additional SNARE complex/synaptotagmin-1 interactions that lead to aggregation and that involve in part two arginines at the bottom of the C2B domain. Overall, this study shows the importance of disentangling the contributions of different types of interactions to SNARE complex/synaptotagmin-1 binding and illustrates the usefulness of one-dimensional NMR methods to analyze intricate protein interactions.

  4. Quantitative H-1 NMR Analysis of Chemical Stabilities in Anion-Exchange Membranes

    SciTech Connect

    Nunez, SA; Hickner, MA

    2013-01-01

    We compared the alkaline stability of three classes of anion exchange membranes that are leading candidates for applications in platinum-free fuel cells. A methodology is presented for the study of chemical stability of anion-exchange polymers in alkaline media that provides clear and quantitative H-1 NMR spectroscopic data of dissolved polymers containing benzyltrimethylammonium functionalities. Recent studies have investigated the stabilities of benzimidazolium- and alkylimidazolium-bearing polymers using periodic H-1 NMR sampling. These studies included varying alkaline concentrations, external heating sources, and excessive processing and contained no internal standard for absolute measurements. Key aspects of our time-resolved H-1 NMR method include in situ heating and sampling within the spectrometer, fixed Stoichiometric relationships between the benzyltrimethylammonium functionalities of each polymer and potassium deuteroxide (KOD), and the incorporation of an internal standard for the absolute measurement of the polymer degradation. In addition, our method permits the identification of the degradation products to find the underlying cause of chemical lability. Our results demonstrate that a styrene-based polymer containing benzyltrimethylammonium functional groups is remarkably stable when exposed to 20 equivalents per cation of KOD at 80 degrees C with a half-life (t(1/2)) of 231 h. Under these standard conditions, functionalized poly(phenylene oxide) and poly(arylene ether sulfone) copolymers, both bearing benzyltrimethylammonium functionalities were found to degrade with a half-lives of 57.8 and 2.7 h, respectively.

  5. 60 MHz (1)H NMR spectroscopy for the analysis of edible oils.

    PubMed

    Parker, T; Limer, E; Watson, A D; Defernez, M; Williamson, D; Kemsley, E Kate

    2014-05-01

    We report the first results from a new 60 MHz (1)H nuclear magnetic resonance (NMR) bench-top spectrometer, Pulsar, in a study simulating the adulteration of olive oil with hazelnut oil. There were qualitative differences between spectra from the two oil types. A single internal ratio of two isolated groups of peaks could detect hazelnut oil in olive oil at the level of ∼13%w/w, whereas a whole-spectrum chemometric approach brought the limit of detection down to 11.2%w/w for a set of independent test samples. The Pulsar's performance was compared to that of Fourier transform infrared (FTIR) spectroscopy. The Pulsar delivered comparable sensitivity and improved specificity, making it a superior screening tool. We also mapped NMR onto FTIR spectra using a correlation-matrix approach. Interpretation of this heat-map combined with the established annotations of the NMR spectra suggested a hitherto undocumented feature in the IR spectrum at ∼1130 cm(-1), attributable to a double-bond vibration. PMID:24850979

  6. Advanced NMR-based techniques for pore structure analysis of coal

    SciTech Connect

    Smith, D.M.

    1992-01-01

    One of the main problems in coal utilization is the inability to properly characterize its complex pore structure. Coals typically have micro/ultra-micro pores but they also exhibit meso and macroporosity. Conventional pore size techniques (adsorption/condensation, mercury porosimetry) are limited because of this broad pore size range, microporosity, reactive nature of coal, samples must be completely dried, and network/percolation effects. Small angle scattering is limited because it probes both open and closed pores. Although one would not expect any single technique to provide a satisfactory description of a coal's structure, it is apparent that better techniques are necessary. We believe that measurement of the NMR parameters of various gas phase and adsorbed phase NMR active probes can provide the resolution to this problem. We now have two suites of well-characterized microporous materials including oxides (zeolites and silica gel) and activated carbons from our industrial partner, Air Products in Allentown, PA. Our current work may be divided into three areas: small-angle X-ray scattering (SAXS), adsorption, and NMR.

  7. NMR and X-ray analysis of structural additivity in metal binding site-swapped hybrids of rubredoxin

    PubMed Central

    LeMaster, David M; Anderson, Janet S; Wang, Limin; Guo, Yi; Li, Hongmin; Hernández, Griselda

    2007-01-01

    Background Chimeric hybrids derived from the rubredoxins of Pyrococcus furiosus (Pf) and Clostridium pasteurianum (Cp) provide a robust system for the characterization of protein conformational stability and dynamics in a differential mode. Interchange of the seven nonconserved residues of the metal binding site between the Pf and Cp rubredoxins yields a complementary pair of hybrids, for which the sum of the thermodynamic stabilities is equal to the sum for the parental proteins. Furthermore, the increase in amide hydrogen exchange rates for the hyperthermophile-derived metal binding site hybrid is faithfully mirrored by a corresponding decrease for the complementary hybrid that is derived from the less thermostable rubredoxin, indicating a degree of additivity in the conformational fluctuations that underlie these exchange reactions. Results Initial NMR studies indicated that the structures of the two complementary hybrids closely resemble "cut-and-paste" models derived from the parental Pf and Cp rubredoxins. This protein system offers a robust opportunity to characterize differences in solution structure, permitting the quantitative NMR chemical shift and NOE peak intensity data to be analyzed without recourse to the conventional conversion of experimental NOE peak intensities into distance restraints. The intensities for 1573 of the 1652 well-resolved NOE crosspeaks from the hybrid rubredoxins were statistically indistinguishable from the intensities of the corresponding parental crosspeaks, to within the baseplane noise level of these high sensitivity data sets. The differences in intensity for the remaining 79 NOE crosspeaks were directly ascribable to localized dynamical processes. Subsequent X-ray analysis of the metal binding site-swapped hybrids, to resolution limits of 0.79 Å and 1.04 Å, demonstrated that the backbone and sidechain heavy atoms in the NMR-derived structures lie within the range of structural variability exhibited among the individual

  8. Phenylalanine and tyrosine methyl ester intramolecular interactions and conformational analysis by (1)H NMR and infrared spectroscopies and theoretical calculations.

    PubMed

    Cormanich, Rodrigo A; Ducati, Lucas C; Tormena, Cláudio F; Rittner, Roberto

    2014-04-01

    Amino acid conformational analysis in solution are scarce, since these compounds present a bipolar zwitterionic structure ((+)H3NCHRCOO(-)) in these media. Also, intramolecular hydrogen bonds have been classified as the sole interactions governing amino acid conformational behavior in the literature. In the present work we propose phenylalanine and tyrosine methyl ester conformational studies in different solvents by (1)H NMR and infrared spectroscopies and theoretical calculations. Both experimental and theoretical results are in agreement and suggest that the conformational behavior of the phenylalanine and tyrosine methyl esters are similar and are dictated by the interplay between steric and hyperconjugative interactions.

  9. Automatic phase correction of fourier transform NMR spectra based on the dispersion versus absorption (DISPA) lineshape analysis

    NASA Astrophysics Data System (ADS)

    Sotak, Christopher H.; Dumoulin, Charles L.; Newsham, Mark D.

    A method for automatic phase correction of Fourier transform NMR spectra bused on the dispersion versus absorption (DISPA) lineshape analysis is described. The DISPA display of a single misphased Lorentzian line gives a unit circle which has been rotated about the origin (relative to its "reference circle") by a number of degrees equal to the phase misadjustment. This rotation, Φ, is a combination of the zero- and first-order phase angles at the frequency of the resonance. Calculation of Φ for two or more resonances allows the spectral phasing parameters to be determined and applied to correct the spectrum. This approach has been implemented in both automatic and "semi-automatic" modes.

  10. /sup 13/C NMR spectroscopy in the analysis of conjugate metabolites in the bile of fish exposed to petroleum

    SciTech Connect

    Hellou, J.; Banoub, J.H.; Payne, J.F.

    1986-01-01

    The first natural abundance /sup 13/C NMR investigation of a complex mixture of conjugate metabolites obtained from the gall bladder bile of fish exposed to hydrocarbons is presented. Cunners were exposed to water accommodated No. 2 fuel oil containing about 68% saturates and 22% aromatics. Spectral analysis indicated that the hydrocarbon derivatives were present predominantly as ..beta..-glucuronides, with the oxygen at carbon-1 of glucuronic acid preferentially attached to an aliphatic carbon. The conjugate metabolites were enriched in aromatic-type carbons when compared to the fuel oil or the aromatic fraction of oil.

  11. sup 31 P saturation transfer and phosphocreatine imaging in the monkey brain

    SciTech Connect

    Mora, B.; Narasimhan, P.T.; Ross, B.D. California Inst. of Tech., Pasadena ); Allman, J. ); Barker, P.B. )

    1991-10-01

    {sup 31}P magnetic resonance imaging with chemical-shift discrimination by selective excitation has been employed to determine the phosphocreatine (PCr) distribution in the brains of three juvenile macaque monkeys. PCr images were also obtained while saturating the resonance of the {gamma}-phosphate of ATP, which allowed the investigation of the chemical exchange between PCr and the {gamma}-phosphate of ATP catalyzed by creatine kinase. Superposition of the PCr images over the proton image of the same monkey brain revealed topological variations in the distribution of PCr and creatine kinase activity. PCr images were also obtained with and without visual stimulation. In two out of four experiments, an apparently localized decrease in PCr concentration was noted in visual cortex upon visual stimulation. This result is interpreted in terms of a possible role for the local ADP concentration in stimulating the accompanying metabolic response.

  12. Abnormal skeletal muscle oxidative capacity after lung transplantation by 31P-MRS.

    PubMed

    Evans, A B; Al-Himyary, A J; Hrovat, M I; Pappagianopoulos, P; Wain, J C; Ginns, L C; Systrom, D M

    1997-02-01

    Although lung transplantation improves exercise capacity by removal of a ventilatory limitation, recipients' postoperative maximum oxygen uptake (VO2max) remains markedly abnormal. To determine if abnormal skeletal muscle oxidative capacity contributes to this impaired aerobic capacity, nine lung transplant recipients and eight healthy volunteers performed incremental quadriceps exercise to exhaustion with simultaneous measurements of pulmonary gas exchange, minute ventilation, blood lactate, and quadriceps muscle pH and phosphorylation potential by 31P-magnetic resonance spectroscopy (31P-MRS). Five to 38 mo after lung transplantation, peak VO2 was decreased compared with that of normal control subjects (6.7 +/- 0.4 versus 12.3 +/- 1.0 ml/min/kg, p < 0.001), even after accounting for differences in age and lean body weight. Neither ventilation, arterial O2 saturation nor mild anemia could account for the decrease in aerobic capacity. Quadriceps muscle intracellular pH (pH(i)) was more acidic at rest (7.07 +/- 0.01 versus 7.12 +/- 0.01 units, p < 0.05) and fell during exercise from baseline values at a lower metabolic rate (282 +/- 21 versus 577 +/- 52 ml/min, p < 0.001). Regressions for pH(i) versus VO2, phosphocreatine/inorganic phosphate ratio (PCr/Pi) versus VO2, and blood lactate versus pH(i) were not different. Among transplant recipients, the metabolic rate at which pH(i) fell correlated closely with VO2max (r = 0.87, p < 0.01). The persistent decrease in VO2max after lung transplantation may be related to abnormalities of skeletal muscle oxidative capacity. PMID:9032203

  13. Solid-State Quantitative (1)H and (31)P MRI of Cortical Bone in Humans.

    PubMed

    Seifert, Alan C; Wehrli, Felix W

    2016-06-01

    Magnetic resonance imaging (MRI) plays a pivotal role for assessment of the musculoskeletal system. It is currently the clinical modality of choice for evaluation of soft tissues including cartilage, ligaments, tendons, muscle, and bone marrow. By comparison, the study of calcified tissue by MRI is still in its infancy. In this article, we review the potential of the modality for assessment of cortical bone properties known to be affected in degenerative bone disease, with focus on parameters related to matrix and mineral densities, and porosity, by means of emerging solid-state (1)H and (31)P MRI techniques. In contrast to soft tissues, the MRI signal in calcified tissues has very short lifetime, on the order of 100 μs to a few milliseconds, demanding customized imaging approaches that allow capture of the signal almost immediately after excitation. The technologies described are suited for quantitatively imaging human cortical bone in specimens as well as in vivo in patients on standard clinical imagers, yielding either concentrations in absolute units when measured against a reference standard, or more simply, in the form of surrogate biomarkers. The two major water fractions in cortical bone are those of collagen-bound and pore water occurring at an approximately 3:1 ratio. Collagen-bound water density provides a direct quantitative measure of osteoid density. While at an earlier stage of development, quantification of mineral phosphorus by (31)P MRI yields mineral density and, together with knowledge of matrix density, should allow quantification of the degree of bone mineralization. PMID:27048472

  14. NBO, HOMO-LUMO, UV, NLO, NMR and vibrational analysis of veratrole using FT-IR, FT-Raman, FT-NMR spectra and HF-DFT computational methods.

    PubMed

    Suvitha, A; Periandy, S; Gayathri, P

    2015-03-01

    This work deals with FT-IR, FT-Raman and FT-NMR spectral analysis and NBO, NLO, HOMO-LUMO and electronic transitions studies on veratrole. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands were interpreted with the aid of structure optimizations and geometrical parameter calculations based on Hartree-Fock (HF) and density functional theory (DFT) method with 6-311++G(d, p) basis set. A study on the electronic properties, such as HOMO and LUMO energies were performed by time independent DFT approach. In addition, molecular electrostatic potential (MEP), Natural Bond-Orbital (NBO) analysis and thermodynamic properties were performed. The (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by gauge independent atomic orbital (GIAO) method and compared with experimental chemical shift.

  15. Preclinical study of treatment response in HCT-116 cells and xenografts with (1) H-decoupled (31) P MRS.

    PubMed

    Darpolor, Moses M; Kennealey, Peter T; Le, H Carl; Zakian, Kristen L; Ackerstaff, Ellen; Rizwan, Asif; Chen, Jin-Hong; Sambol, Elliot B; Schwartz, Gary K; Singer, Samuel; Koutcher, Jason A

    2011-11-01

    The topoisomerase I inhibitor, irinotecan, and its active metabolite SN-38 have been shown to induce G(2) /M cell cycle arrest without significant cell death in human colon carcinoma cells (HCT-116). Subsequent treatment of these G(2) /M-arrested cells with the cyclin-dependent kinase inhibitor, flavopiridol, induced these cells to undergo apoptosis. The goal of this study was to develop a noninvasive metabolic biomarker for early tumor response and target inhibition of irinotecan followed by flavopiridol treatment in a longitudinal study. A total of eleven mice bearing HCT-116 xenografts were separated into two cohorts where one cohort was administered saline and the other treated with a sequential course of irinotecan followed by flavopiridol. Each mouse xenograft was longitudinally monitored with proton ((1) H)-decoupled phosphorus ((31) P) magnetic resonance spectroscopy (MRS) before and after treatment. A statistically significant decrease in phosphocholine (p = 0.0004) and inorganic phosphate (p = 0.0103) levels were observed in HCT-116 xenografts following treatment, which were evidenced within twenty-four hours of treatment completion. Also, a significant growth delay was found in treated xenografts. To discern the underlying mechanism for the treatment response of the xenografts, in vitro HCT-116 cell cultures were investigated with enzymatic assays, cell cycle analysis, and apoptotic assays. Flavopiridol had a direct effect on choline kinase as measured by a 67% reduction in the phosphorylation of choline to phosphocholine. Cells treated with SN-38 alone underwent 83 ± 5% G(2) /M cell cycle arrest compared to untreated cells. In cells, flavopiridol alone induced 5 ± 1% apoptosis while the sequential treatment (SN-38 then flavopiridol) resulted in 39 ± 10% apoptosis. In vivo (1) H-decoupled (31) P MRS indirectly measures choline kinase activity. The decrease in phosphocholine may be a potential indicator of early tumor response to

  16. 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.

  17. Analysis of liquid-solids suspension velocities and concentrations obtained by NMR imaging

    SciTech Connect

    Ding, J.; Lyczkowski, R.W.; Sha, W.T. ); Altobelli, S.A.; Fukushima, E. )

    1992-09-01

    COMMIX-M, a three-dimensional transient and steady-state computer program written in Cartesian and cylindrical coordinates, has been developed by Argonne National Laboratory. This computer program is capable of analyzing multiphase flow and heat transfer and utilizes the separate phases model wherein each phase has its own mass, momentum, and energy equations. This computer program is in its early stages of development for application to test various interphase interaction models and to predict design and processing of dense fluid-solids suspension systems. COMMIX-M contains preliminary constitutive relationships for interfacial drag, solids viscosities and stresses to describe the solids rheology, and shear lift forces from the literature. Also included is a solids partial slip boundary condition to allow non-zero tangential velocity at the tube walls. Analyses of some of the steady-state, fully-developed isothermal carrier fluid velocity and solids concentration data of Altobelli et al. and Sinton and Chow are presented. These experimental data obtained using three-dimensional time-of-flight nuclear magnetic (NMR) imaging techniques were carefully performed and represent some of the best available open literature data of their kind. NMR imaging offers powerful techniques to non-intrusively determine three-dimensional time-dependent velocity and concentration fields to assist development and validation of the constitutive models and the computer programs describing concentrated suspensions. Analyses of these NMR data, together with comparisons of computed and measured concentration and velocity profiles provide some insights into the mechanisms governing the observed phenomena. Recommendations for future research are given. To the authors' knowledge, these are the first such comparisons of theory and experiment.

  18. Analysis of liquid-solids suspension velocities and concentrations obtained by NMR imaging

    SciTech Connect

    Ding, J.; Lyczkowski, R.W.; Sha, W.T.; Altobelli, S.A.; Fukushima, E.

    1992-09-01

    COMMIX-M, a three-dimensional transient and steady-state computer program written in Cartesian and cylindrical coordinates, has been developed by Argonne National Laboratory. This computer program is capable of analyzing multiphase flow and heat transfer and utilizes the separate phases model wherein each phase has its own mass, momentum, and energy equations. This computer program is in its early stages of development for application to test various interphase interaction models and to predict design and processing of dense fluid-solids suspension systems. COMMIX-M contains preliminary constitutive relationships for interfacial drag, solids viscosities and stresses to describe the solids rheology, and shear lift forces from the literature. Also included is a solids partial slip boundary condition to allow non-zero tangential velocity at the tube walls. Analyses of some of the steady-state, fully-developed isothermal carrier fluid velocity and solids concentration data of Altobelli et al. and Sinton and Chow are presented. These experimental data obtained using three-dimensional time-of-flight nuclear magnetic (NMR) imaging techniques were carefully performed and represent some of the best available open literature data of their kind. NMR imaging offers powerful techniques to non-intrusively determine three-dimensional time-dependent velocity and concentration fields to assist development and validation of the constitutive models and the computer programs describing concentrated suspensions. Analyses of these NMR data, together with comparisons of computed and measured concentration and velocity profiles provide some insights into the mechanisms governing the observed phenomena. Recommendations for future research are given. To the authors` knowledge, these are the first such comparisons of theory and experiment.

  19. Solid-state NMR analysis of membrane proteins and protein aggregates by proton detected spectroscopy

    PubMed Central

    Nieuwkoop, Andrew J.; Berthold, Deborah A.; Comellas, Gemma; Sperling, Lindsay J.; Tang, Ming; Shah, Gautam J.; Brea, Elliott J.; Lemkau, Luisel R.

    2012-01-01

    Solid-state NMR has emerged as an important tool for structural biology and chemistry, capable of solving atomic-resolution structures for proteins in membrane-bound and aggregated states. Proton detection methods have been recently realized under fast magic-angle spinning conditions, providing large sensitivity enhancements for efficient examination of uniformly labeled proteins. The first and often most challenging step of protein structure determination by NMR is the site-specific resonance assignment. Here we demonstrate resonance assignments based on high-sensitivity proton-detected three-dimensional experiments for samples of different physical states, including a fully-protonated small protein (GB1, 6 kDa), a deuterated microcrystalline protein (DsbA, 21 kDa), a membrane protein (DsbB, 20 kDa) prepared in a lipid environment, and the extended core of a fibrillar protein (α-synuclein, 14 kDa). In our implementation of these experiments, including CONH, CO(CA)NH, CANH, CA(CO)NH, CBCANH, and CBCA(CO)NH, dipolar-based polarization transfer methods have been chosen for optimal efficiency for relatively high protonation levels (full protonation or 100 % amide proton), fast magic-angle spinning conditions (40 kHz) and moderate proton decoupling power levels. Each H–N pair correlates exclusively to either intra- or inter-residue carbons, but not both, to maximize spectral resolution. Experiment time can be reduced by at least a factor of 10 by using proton detection in comparison to carbon detection. These high-sensitivity experiments are especially important for membrane proteins, which often have rather low expression yield. Proton-detection based experiments are expected to play an important role in accelerating protein structure elucidation by solid-state NMR with the improved sensitivity and resolution. PMID:22986689

  20. Analysis of Hydroperoxides in solid Polyethylene by NMR and EPR Spectroscopy

    SciTech Connect

    ASSINK,ROGER A.; CELINA,MATHIAS C.; DUNBAR,TIMOTHY D.; ALAM,TODD M.; CLOUGH,ROGER LEE; GILLEN,KENNETH T.

    2000-06-12

    The authors have shown that the hydroperoxide species in {gamma}-irradiated {sup 13}C-polyethylene can be directly observed by {sup 13}C MAS NMR spectroscopy. The experiment was performed without the need for special sample preparation such as chemical derivatization or dissolution. Annealing experiments were employed to study the thermal decomposition of the hydroperoxide species and to measure an activation energy of 98 kJ/mol. EPR spectroscopy suggests that residual polyenyl and alkylperoxy radicals are predominantly trapped in interracial or crystalline regions, while the peroxy radicals observed after UV-photolysis of hydroperoxides are in amorphous regions.

  1. Evaluation of Automated Low-Field NMR Relaxometry For Analysis of Polymers

    SciTech Connect

    Wilson, Mark

    2008-12-04

    Screening studies and a Design of Experiment were performed to evaluate measurement variation of a new, non-destructive NMR test system designed to assess age induced degradation of Outer Pressure Pads. The test method and results from 76,746 measurements are described indicating that a metal support strut adjacent to the front position of the test chamber interferes with the measurements and that there is a measurement property gradient from the front to the back of the chamber. Also, obvious compression set areas on a surveillance OPP were not detected, but hidden, internal voids within a newly molded OPP were detected.

  2. Conformational analysis of Ramipril (HOE 498) in a solution by NMR

    NASA Astrophysics Data System (ADS)

    Sakamoto, Yohko; Ishii, Tomoko; Oonishi, Isao; Ohmoto, Taichi

    1991-05-01

    Conformations of Ramipril (Hoe 498, 2-[ N-(S)-1-ethoxycarbonyl-3-phenylpropyl]-L-alanyl-(1S, 3S, 5S)-2-azabicyclo (3,3,0) octane-3-carboxylic acid), a non-sulfhydryl angiotensin I converting enzyme (ACE) inhibitor, were investigated in CD 3OD, to account for their specific biological activity and long-lasting effectiveness. The preferred optimum structures of the cis and trans forms are postulated. The identification of the two conformers is based on NMR measurements and classical energy calculations. The cis conformation should be preferred for biological activity.

  3. Characterization of tea cultivated at four different altitudes using 1H NMR analysis coupled with multivariate statistics.

    PubMed

    Ohno, Akiko; Oka, Kitaro; Sakuma, Chiseko; Okuda, Haruhiro; Fukuhara, Kiyoshi

    2011-05-25

    The taste of black tea differs according to the different areas in which the tea is grown, even for the same species of tea. A combination of (1)H NMR spectroscopy and partial least-squares discriminate analysis (PLS-DA) was used to assess the quality differences of tea leaves from four cultivation areas with different elevations, RAN > 1800 m, UDA = 1200 m, MEDA = 600 m, and YATA < 300 m, in Sri Lanka. As a result of a statistical analysis, PLS-DA showed a separation between high- and low-quality black teas derived from the four different tea cultivation areas. RAN from the highest elevation showed characteristic trends in the levels of theaflavin and theaflavin 3,3'-digallate that were found only in RAN, and the levels of theanine and caffeine were higher, and the levels of thearubigins, especially thearubigin 3,3'-digallate, were lower in RAN than in UDA, MEDA, and YATA. The structures of these components were determined by 1D and 2D NMR analyses. These results demonstrate that this method can be used to evaluate black tea quality according to the chemical composition or metabolites, which are characteristic of the tea leaves cultivated in four regions with different elevations in Sri Lanka.

  4. A novel analysis for the NMR magic sandwich echo in polymers: application to the α-relaxation in polybutadiene

    NASA Astrophysics Data System (ADS)

    Pieruccini, Marco; Sturniolo, Simone; Corti, Maurizio; Rigamonti, Attilio

    2015-11-01

    On the basis of a method to describe the relaxation dynamics in an ensemble of spin pairs, an analytical expression is derived for the magic sandwich echo refocusing efficiency of 1H-NMR signals from systems where dipolar interaction dominates. At the sake of illustration the method is applied to the analysis of the α-relaxation in poly(butadiene). The Vogel-Fulcher-Tammann behaviour of the central relaxation rates, derived by fitting the refocusing efficiency as a function of the temperature, follows very well independent measurements performed with stimulated echo 2H-NMR experiments. Comparison with literature data worked out by broad band dielectric spectroscopy also shows very good agreement. In the framework of an Havriliak-Negami representation of the distribution of correlation times, information about width and asymmetry of the frequency profile is also provided by the analysis. This novel method is believed to represent a suitable path to extract basic information on the motional distribution in a variety of similar systems.

  5. Metabolism of D-glucose in a wall-less mutant of Neurospora crassa examined by /sup 13/C and /sup 31/P nuclear magnetic resonances: effects of insulin

    SciTech Connect

    Greenfield, N.J.; McKenzie, M.A.; Adebodun, F.; Jordan, F.; Lenard, J.

    1988-11-15

    /sup 13/C NMR and /sup 31/P NMR have been used to investigate the metabolism of glucose by a wall-less strain of Neurospora crassa (slime), grown in a supplemented nutritionally defined medium and harvested in the early stationary stage of growth. With D-(1-/sup 13/C)- or D-(6-/sup 13/C)glucose as substrates, the major metabolic products identified from /sup 13/C NMR spectra were (2-/sup 13/C)ethanol, (3-/sup 13/C)alanine, and C/sub 1/- and C/sub 6/-labeled trehalose. Several observations suggested the existence of a substantial hexose monophosphate (HMP) shunt: (i) a 70% greater yield of ethanol from C/sub 6/- than from C/sub 1/-labeled glucose; (ii) C/sub 1/-labeled glucose yielded 19% C/sub 6/-labeled trehalose, while C/sub 6/-labeled glucose yielded only 4% C/sub 1/-labeled trehalose; (iii) a substantial transfer of /sup 13/C from C/sub 2/-labeled glucose to the C/sub 2/-position of ethanol. /sup 31/P NMR spectra showed millimolar levels of intracellular inorganic phosphate (P/sub i/), phosphodiesters, and diphosphates including sugar diphosphates and polyphosphate. Addition of glucose resulted in a decrease in cytoplasmic P/sub i/ and an increase in sugar monophosphates, which continued for at least 30 min. Phosphate resonances corresponding to metabolic intermediates of both the glycolytic and HMP pathways were identified in cell extracts. Addition of insulin (100 nM) with the glucose had the following effects relative to glucose alone: (i) a 24% increase in the rate of ethanol production; (ii) a 38% increase in the rate of alanine production; (iii) a 27% increase in the rate of glucose disappearance. Insulin thus increases the rates of production of ethanol and alanine in these cells, in addition to increasing production of CO/sub 2/ and glycogen, as previously shown.

  6. Predicting the redox state and secondary structure of cysteine residues using multi-dimensional classification analysis of NMR chemical shifts.

    PubMed

    Wang, Ching-Cheng; Lai, Wen-Chung; Chuang, Woei-Jer

    2016-09-01

    A tool for predicting the redox state and secondary structure of cysteine residues using multi-dimensional analyses of different combinations of nuclear magnetic resonance (NMR) chemical shifts has been developed. A data set of cysteine [Formula: see text], (13)C(α), (13)C(β), (1)H(α), (1)H(N), and (15)N(H) chemical shifts was created, classified according to redox state and secondary structure, using a library of 540 re-referenced BioMagResBank (BMRB) entries. Multi-dimensional analyses of three, four, five, and six chemical shifts were used to derive rules for predicting the structural states of cysteine residues. The results from 60 BMRB entries containing 122 cysteines showed that four-dimensional analysis of the C(α), C(β), H(α), and N(H) chemical shifts had the highest prediction accuracy of 100 and 95.9 % for the redox state and secondary structure, respectively. The prediction of secondary structure using 3D, 5D, and 6D analyses had the accuracy of ~90 %, suggesting that H(N) and [Formula: see text] chemical shifts may be noisy and made the discrimination worse. A web server (6DCSi) was established to enable users to submit NMR chemical shifts, either in BMRB or key-in formats, for prediction. 6DCSi displays predictions using sets of 3, 4, 5, and 6 chemical shifts, which shows their consistency and allows users to draw their own conclusions. This web-based tool can be used to rapidly obtain structural information regarding cysteine residues directly from experimental NMR data.

  7. Conformational analysis of 2-halocyclopentanones by NMR and IR spectroscopies and theoretical calculations.

    PubMed

    Martins, Carina R; Ducati, Lucas C; Tormena, Cláudio F; Rittner, Roberto

    2009-06-01

    The conformational isomerism of 2-chlorocyclopentanone and 2-bromocyclopentanone has been determined through the solvent dependence of the (1)H NMR (3)J(HH) coupling constants, theoretical calculations and infrared data, using the solvation theory for the treatment of NMR data. In 2-chlorocyclopentanone, the energy difference (E(Psi-e)-E(Psi-a)), in the isolated molecule at B3LYP level of theory, between the pseudo-equatorial (Psi-e) and pseudo-axial (Psi-a) conformers is 0.42kcalmol(-1), which decreases in CCl(4) and in acetonitrile solutions, in good agreement with infrared data (nu(CO)), despite the uncertainties of the latter method. The conformational equilibrium for 2-bromocyclopentanone is also between the Psi-e and Psi-a conformations, with an energy difference (E(Psi-e)-E(Psi-a)), in the isolated molecule at B3LYP level of theory, is 0.85kcalmol(-1) which decreases in CCl(4) and in acetonitrile solutions, also in good agreement with infrared data.

  8. Structural Analysis of Nanoscale Self-Assembled Discoidal Lipid Bilayers by Solid-State NMR Spectroscopy

    PubMed Central

    Li, Ying; Kijac, Aleksandra Z.; Sligar, Stephen G.; Rienstra, Chad M.

    2006-01-01

    Nanodiscs are an example of discoidal nanoscale self-assembled lipid/protein particles similar to nascent high-density lipoproteins, which reduce the risk of coronary artery disease. The major protein component of high-density lipoproteins is human apolipoprotein A-I, and the corresponding protein component of Nanodiscs is membrane scaffold protein 1 (MSP1), a 200-residue lipid-binding domain of human apolipoprotein A-I. Here we present magic-angle spinning (MAS) solid-state NMR studies of uniformly 13C,15N-labeled MSP1 in polyethylene glycol precipitated Nanodiscs. Two-dimensional MAS 13C-13C correlation spectra show excellent microscopic order of MSP1 in precipitated Nanodiscs. Secondary isotropic chemical shifts throughout the protein are consistent with a predominantly helical structure. Moreover, the backbone conformations of prolines derived from their 13C chemical shifts are consistent with the molecular belt model but not the picket fence model of lipid-bound MSP1. Overall comparison of experimental spectra and 13C chemical shifts predicted from several structural models also favors the belt model. Our study thus supports the belt model of Nanodisc structure and demonstrates the utility of MAS NMR to study the structure of high molecular weight lipid-protein complexes. PMID:16905610

  9. ¹³C solid-state NMR analysis of the most common pharmaceutical excipients used in solid drug formulations, Part I: Chemical shifts assignment.

    PubMed

    Pisklak, Dariusz Maciej; Zielińska-Pisklak, Monika Agnieszka; Szeleszczuk, Łukasz; Wawer, Iwona

    2016-04-15

    Solid-state NMR is an excellent and useful method for analyzing solid-state forms of drugs. In the (13)C CP/MAS NMR spectra of the solid dosage forms many of the signals originate from the excipients and should be distinguished from those of active pharmaceutical ingredient (API). In this work the most common pharmaceutical excipients used in the solid drug formulations: anhydrous α-lactose, α-lactose monohydrate, mannitol, sucrose, sorbitol, sodium starch glycolate type A and B, starch of different origin, microcrystalline cellulose, hypromellose, ethylcellulose, methylcellulose, hydroxyethylcellulose, sodium alginate, magnesium stearate, sodium laurilsulfate and Kollidon(®) were analyzed. Their (13)C CP/MAS NMR spectra were recorded and the signals were assigned, employing the results (R(2): 0.948-0.998) of GIPAW calculations and theoretical chemical shifts. The (13)C ssNMR spectra for some of the studied excipients have not been published before while for the other signals in the spectra they were not properly assigned or the assignments were not correct. The results summarize and complement the data on the (13)C ssNMR analysis of the most common pharmaceutical excipients and are essential for further NMR studies of API-excipient interactions in the pharmaceutical formulations.

  10. ¹³C solid-state NMR analysis of the most common pharmaceutical excipients used in solid drug formulations, Part I: Chemical shifts assignment.

    PubMed

    Pisklak, Dariusz Maciej; Zielińska-Pisklak, Monika Agnieszka; Szeleszczuk, Łukasz; Wawer, Iwona

    2016-04-15

    Solid-state NMR is an excellent and useful method for analyzing solid-state forms of drugs. In the (13)C CP/MAS NMR spectra of the solid dosage forms many of the signals originate from the excipients and should be distinguished from those of active pharmaceutical ingredient (API). In this work the most common pharmaceutical excipients used in the solid drug formulations: anhydrous α-lactose, α-lactose monohydrate, mannitol, sucrose, sorbitol, sodium starch glycolate type A and B, starch of different origin, microcrystalline cellulose, hypromellose, ethylcellulose, methylcellulose, hydroxyethylcellulose, sodium alginate, magnesium stearate, sodium laurilsulfate and Kollidon(®) were analyzed. Their (13)C CP/MAS NMR spectra were recorded and the signals were assigned, employing the results (R(2): 0.948-0.998) of GIPAW calculations and theoretical chemical shifts. The (13)C ssNMR spectra for some of the studied excipients have not been published before while for the other signals in the spectra they were not properly assigned or the assignments were not correct. The results summarize and complement the data on the (13)C ssNMR analysis of the most common pharmaceutical excipients and are essential for further NMR studies of API-excipient interactions in the pharmaceutical formulations. PMID:26845204

  11. Synthesis, NMR characterization, X-ray structural analysis and theoretical calculations of amide and ester derivatives of the coumarin scaffold

    NASA Astrophysics Data System (ADS)

    Matos, Maria J.; Uriarte, Eugenio; Santana, Lourdes; Vilar, Santiago

    2013-06-01

    Compounds 1 (4-methyl-N-(coumarin-3-yl)benzamide) and 2 ((coumarin-3-yl)-4-methylbenzoate) were synthesized by linking the coumarin system (3-aminocoumarin or 3-hydroxycoumarin, respectively) to a p-toluoylchloride. 1H and 13C NMR and X-ray diffractometry determined the molecular structures of both derivatives. The X-ray results were compared to those obtained by conformational analysis followed by semiempirical methodologies (AM1 and PM3). The theoretical calculations yielded results reproducing the whole three-dimensional (3D) structure of both molecules in a good agreement with X-ray structural analysis. The global structures of the two compounds are very similar in the two studied environments, meaning that the structural determination in the gas phase can be extrapolated. A comparative study between compounds 1 and 2, based on the structural results, was carried out.

  12. The inclusion complex of rosmarinic acid into beta-cyclodextrin: A thermodynamic and structural analysis by NMR and capillary electrophoresis.

    PubMed

    Aksamija, Amra; Polidori, Ange; Plasson, Raphaël; Dangles, Olivier; Tomao, Valérie

    2016-10-01

    This work focuses on the characterization of the rosmarinic acid (RA)-β-cyclodextrin (CD) complex in aqueous solution by (1)H NMR (1D- and 2D-ROESY), completed with studies by capillary electrophoresis (CE). From the (1)H NMR data, the stoichiometry of the complex was determined by a Job's plot and the binding constant was estimated from a linear regression (Scott's method). At pH 2.9, the results showed that RA binds CD with a 1:1 stoichiometry and a binding constant Kb of 445 (±53) M(-1) or 465 (±81) M(-1) depending on the CD protons (H-5 or H-3) selected for the evaluation. The Kb value was also calculated from the CD-induced chemical shifts of each RA proton in order to collect information on the structure of the complex. The pH dependence of Kb revealed that the RA carboxylic form displays the highest affinity for CD. An investigation by capillary electrophoresis fully confirmed these results. 2D ROESY analysis provided detailed structural information on the complex and showed a strong correlation between H-3 and H-5 of CD and most RA protons. In conclusion, RA, an efficient phenolic antioxidant from rosemary with a marketing authorization, spontaneously forms a relatively stable inclusion complex with CD in water. PMID:27132848

  13. 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.

  14. [Discrimination of patients with Xiao-Chaihu Tang syndrome using 1H NMR metabonomics and partial least square analysis].

    PubMed

    Xing, Jie; Yuan, Shu-chun; Sun, Hui-min; Fan, Ma-li; Li, Zhen-yu; Qin, Xue-mei

    2015-08-01

    1H NMR metabonomics approach was used to reveal the chemical difference of urine between patients with Xiao-Chaihu Tang syndrome (XCHTS) and healthy participants (HP). The partial least square method was used to establish a model to distinguish the patients with Xiao-Chaihu-Tang syndrome from the healthy controls. Thirty-four endogenous metabolites were identified in the 1H NMR spectrum, and orthogonal partial least squares discriminant analysis showed the urine of patients with Xiao-Chaihu Tang syndrome and healthy participants could be separated clearly. It is indicated that the metabolic profiling of patients with Xiao-Chaihu Tang syndrome was changed obviously. Fifteen metabolites were found by S-pot of OPLS-DA and VIP value. The contents of leucine, formic acid, glycine, hippuric acid and uracil increased in the urine of patients, while threonine, 2-hydroxyisobutyrate, acetamide, 2-oxoglutarate, citric acid, dimethylamine, malonic acid, betaine, trimethylamine oxide, phenylacetyl glycine, and uridine decreased. These metabolites involve the intestinal microbial balance, energy metabolism and amino acid metabolism pathways, which is related with the major symptom of Xiao-Chaihu Tang syndrome. The patients with Xiao-Chaihu Tang syndrome could be identified and predicted correctly using the established partial least squares model. This study could be served as the basis for the accurate diagnostic and reasonable administration of Xiao-Chaihu-Tang syndrome.

  15. High-sensitivity chemical derivatization NMR analysis for condition monitoring of aged elastomers.

    SciTech Connect

    Assink, Roger Alan; Celina, Mathias Christopher; Skutnik, Julie Michelle

    2004-06-01

    An aged polybutadiene-based elastomer was reacted with trifluoroacetic anhydride (TFAA) and subsequently analyzed via 19F NMR spectroscopy. Derivatization between the TFAA and hydroxyl functionalities produced during thermo-oxidative aging was achieved, resulting in the formation of trifluoroester groups on the polymer. Primary and secondary alcohols were confirmed to be the main oxidation products of this material, and the total percent oxidation correlated with data obtained from oxidation rate measurements. The chemical derivatization appears to be highly sensitive and can be used to establish the presence and identity of oxidation products in aged polymeric materials. This methodology represents a novel condition monitoring approach for the detection of chemical changes that are otherwise difficult to analyze.

  16. Advanced NMR-based techniques for pore structure analysis of coal

    SciTech Connect

    Smith, D.M.

    1991-01-01

    One of the main problems in coal utilization is the inability to properly characterize its complex pore structure. We propose to investigate the dependence of the common NMR parameters such as chemical shifts and relaxation times of several different nuclei and compounds on the pore structure of model microporous solids, carbons, and coals. In particular, we will study the interaction between several small molecules ({sup 129}Xe, {sup 3}He, {sup 2}H{sub 2}, {sup 14}N{sub 2}, {sup 14}NH{sub 3}, {sup 15}N{sub 2}, {sup 13}CH{sub 4}, {sup 13}CO{sub 2}) and the pore surfaces in coals. These molecules have been selected for their chemical and physical properties.

  17. NMR-Based Metabolomic Analysis of Huanglongbing-Asymptomatic and -Symptomatic Citrus Trees.

    PubMed

    Freitas, Deisy dos Santos; Carlos, Eduardo Fermino; Gil, Márcia Cristina Soares de Souza; Vieira, Luiz Gonzaga Esteves; Alcantara, Glaucia Braz

    2015-09-01

    Huanglongbing (HLB) is one of the most severe diseases that affects citrus trees worldwide and is associated with the yet uncultured bacteria Candidatus Liberibacter spp. To assess the metabolomic differences between HLB-asymptomatic and -symptomatic tissues, extracts from leaf and root samples taken from a uniform 6-year-old commercial orchard of Valencia trees were subjected to nuclear magnetic resonance (NMR) and chemometrics. The results show that the symptomatic trees had higher sucrose content in their leaves and no variation in their roots. In addition, proline betaine and malate were detected in smaller amounts in the HLB-affected symptomatic leaves. The changes in metabolic processes of the plant in response to HLB are corroborated by the relationship between the bacterial levels and the metabolic profiles.

  18. NMR-like Operation and Analysis of Decoherence of a Superconducting Quantum Bit

    NASA Astrophysics Data System (ADS)

    Vion, Denis

    2005-03-01

    The Quantronium [1], a superconducting circuit with Josephson junctions, can be regarded as a solid state qubit prototype with built-in decoupling from its environment. We demonstrate that arbitrary operators can be applied to it using NMR-like and atomic physics-like techniques that involve quasi-resonant microwave or adiabatic DC pulses [2]. Then, we explain how the symmetry of the circuit limits decoherence of a superposition of states, at an optimal working point. Coherence time measurements, performed both during free and driven evolution of the qubit are presented and analyzed using a simple model involving different noise sources. A complete picture of decoherence in this quantum electrical circuit is thus provided. [1] D. Vion et al., Science 296 (2002). [2] E. Collin et al., Phys. Rev. Lett. 93, 15, (2004).

  19. NMR signal analysis to characterize solid, aqueous, and lipid phases in baked cakes.

    PubMed

    Le Grand, F; Cambert, M; Mariette, F

    2007-12-26

    Proton mobility was studied in molecular fractions of some model systems and of cake using a 1H nuclear magnetic resonance (NMR) relaxation technique. For cake, five spin-spin relaxation times (T2) were obtained from transverse relaxation curves: T2 (1) approximately 20 micros, T2 (2) approximately 0.2 ms, T2 (3) approximately 3 ms, T2 (4) approximately 50 ms, and T2 (2) approximately 165 ms. The faster component was attributed to the solid phase, components 2 and 3 were associated with the aqueous phase, and the two slowest components were linked to the lipid phase. After cooking, the crust contained more fat but less water than the center part of the cake. The amount of gelatinized starch was lower in the crust, and water was more mobile due to less interaction with macromolecules. This preliminary study revealed different effects of storage on the center and crust.

  20. NMR imaging and hydrodynamic analysis of neutrally buoyant non-Newtonian slurry flows

    NASA Astrophysics Data System (ADS)

    Bouillard, J. X.; Sinton, S. W.

    The flow of solids loaded suspension in cylindrical pipes has been the object of intense experimental and theoretical investigations in recent years. These types of flows are of great interest in chemical engineering because of their important use in many industrial manufacturing processes. Such flows are for example encountered in the manufacture of solid-rocket propellants, advanced ceramics, reinforced polymer composites, in heterogeneous catalytic reactors, and in the pipeline transport of liquid-solids suspensions. In most cases, the suspension microstructure and the degree of solids dispersion greatly affect the final performance of the manufactured product. For example, solid propellant pellets need to be extremely-well dispersed in gel matrices for use as rocket engine solid fuels. The homogeneity of pellet dispersion is critical to allow good uniformity of the burn rate, which in turn affects the final mechanical performance of the engine. Today's manufacturing of such fuels uses continuous flow processes rather than batch processes. Unfortunately, the hydrodynamics of such flow processes is poorly understood and is difficult to assess because it requires the simultaneous measurements of liquid/solids phase velocities and volume fractions. Due to the recent development in pulsed Fourier Transform NMR imaging, NMR imaging is now becoming a powerful technique for the non intrusive investigation of multi-phase flows. This paper reports and exposes a state-of-the-art experimental and theoretical methodology that can be used to study such flows. The hydrodynamic model developed for this study is a two-phase flow shear thinning model with standard constitutive fluid/solids interphase drag and solids compaction stresses. this model shows good agreement with experimental data and the limitations of this model are discussed.

  1. NMR imaging and hydrodynamic analysis of neutrally buoyant non-Newtonian slurry flows

    SciTech Connect

    Bouillard, J.X.; Sinton, S.W.

    1995-02-01

    The flow of solids loaded suspension in cylindrical pipes has been the object of intense experimental and theoretical investigations in recent years. These types of flows are of great interest in chemical engineering because of their important use in many industrial manufacturing processes. Such flows are for example encountered in the manufacture of solid-rocket propellants, advanced ceramics, reinforced polymer composites, in heterogenous catalytic reactors, and in the pipeline transport of liquid-solids suspensions. In most cases, the suspension microstructure and the degree of solids dispersion greatly affect the final performance of the manufactured product. For example, solid propellant pellets need to be extremely-well dispersed in gel matrices for use as rocket engine solid fuels. The homogeneity of pellet dispersion is critical to allow good uniformity of the burn rate, which in turn affects the final mechanical performance of the engine. Today`s manufacturing of such fuels uses continuous flow processes rather than batch processes. Unfortunately, the hydrodynamics of such flow processes is poorly understood and is difficult to assess because it requires the simultaneous measurements of liquid/solids phase velocities and volume fractions. Due to the recent development in pulsed Fourier Transform NMR imaging, NMR imaging is now becoming a powerful technique for the non intrusive investigation of multi-phase flows. This paper reports and exposes a state-of-the-art experimental and theoretical methodology that can be used to study such flows. The hydrodynamic model developed for this study is a two-phase flow shear thinning model with standard constitutive fluid/solids interphase drag and solids compaction stresses. this model shows good agreement with experimental data and the limitations of this model are discussed.

  2. Conformational analysis of oleandomycin and its 8-methylene-9-oxime derivative by NMR and molecular modelling.

    PubMed

    Novak, Predrag; Tomisić, Zrinka Banić; Tepes, Predrag; Lazarevski, Gorjana; Plavec, Janez; Turkalj, Gordana

    2005-01-01

    Conformations of the 14-membered macrolide antibiotic oleandomycin and its 8-methylene-9-oxime derivative were determined in various solvents. The experimental NMR data--coupling constants and NOE contacts--were compared with the results of molecular modelling--molecular mechanics calculations and molecular dynamics simulations. The conformational changes, on the right-hand side of the 14-membered ring, affected mostly the 3JH2,H3 values and NOE crosspeaks H3 or H4 to H11. Oleandomycin was found to be present predominantly in the C3-C5 folded-in conformations in DMSO-d6 solution, whereas in buffered D2O, acetone-d6 and CDCl3, there was a mixture of folded-in and folded-out conformational families. The predominant conformation of the 8-methylene-oleandomycin-9-oxime derivative in solution was a folded-out one although different amounts of folded-in conformation were also present depending on the solvent. Oleandrose and desosamine sugar moieties adopted the usual and expected chair conformation. The conformation around the glycosidic bonds, governing the relative orientation of sugars vs. the lactone ring, showed a certain flexibility within two conformationally close families. We believe that by combining the experimental NMR data and the molecular modelling techniques, as reported in this paper, we have made significant progress in understanding the conformational behaviour and properties of macrolides. Our belief is based on our own current studies on oleandomycins as well as on the previously reported results and best practices concerning other macrolides. A rational for macrolide conformational studies and advances in methodology has been suggested accordingly. PMID:15602597

  3. Metabolic changes in rat brain after prolonged ethanol consumption measured by 1H and 31P MRS experiments.

    PubMed

    Braunová, Z; Kasparová, S; Mlynárik, V; Mierisová, S; Liptaj, T; Tkác, I; Gvozdjáková, A

    2000-12-01

    1. In vivo 1H and 31P magnetic resonance spectroscopy techniques were applied to reveal biochemical changes in the rat brain caused by prolonged ethanol consumption. 2. Three models of ethanol intoxication were used. 3. 1H MRS showed a significant decrease in the concentration of myo-inositol in the brain of rats fed with 20% ethanol for 8 weeks. This change is consistent with perturbances in astrocytes. On the other hand, N-acetyl aspartate and choline content did not differ from controls. 4. 31P MRS did not reveal any significant changes in the high-energy phosphates or intracellular free Mg2+ content in the brain of rats after 14 weeks of 20% ethanol drinking. The intracellular pH was diminished. 5. By means of a 31P saturation transfer technique, a significant decrease was observed for the pseudo first-order rate constant k(for) of the creatine kinase reaction in the brain of rats administered 30% ethanol for 3 weeks using a gastric tube. 6. The 1H MRS results may indicate that myo-inositol loss, reflecting a disorder in astrocytes, might be one of the first changes associated with alcoholism, which could be detected in the brain by means of in vivo 1H MRS. 7. The results from 31p MRS experiments suggest that alcoholism is associated with decreased brain energy metabolism. 8. 31P saturation transfer, which provides insight into the turnover of high-energy phosphates, could be a more suitable technique for studying the brain energetics in chronic pathological states than conventional 31P MRS. PMID:11100978

  4. Hyperpolarization of 29Si by Resonant Nuclear Spin Transfer from Optically Hyperpolarized 31P Donors

    NASA Astrophysics Data System (ADS)

    Dluhy, Phillip; Salvail, Jeff; Saeedi, Kamyar; Thewalt, Mike; Simons, Stephanie

    2014-03-01

    Recent developments in nanomedicine have allowed nanoparticles of silicon containing hyperpolarized 29Si to be imaged in vivo using magnetic resonance imaging. The extremely long relaxation times and isotropy of the Si lattice make polarized 29Si isotopes ideal for these sorts of imaging methods. However, one of the major difficulties standing in the path of widespread adoption of these techniques is the slow rate at which the 29Si is hyperpolarized and the limited maximum hyperpolarization achievable. In this talk, I will describe an effective method for hyperpolarization of the 29Si isotopes using resonant optical pumping of the donor bound exciton transitions to polarize the 31P donor nuclei, and a choice of static magnetic field that conserves energy during spin flip flops between donor nuclear and 29Si spins to facilitate diffusion of this polarization. Using this method, we are able to polarize greater than 10% of the 29Si centers in 64 hours without seeing saturation of the 29Si polarization.

  5. Bioenergetic Measurements in Children with Bipolar Disorder: A Pilot 31P Magnetic Resonance Spectroscopy Study

    PubMed Central

    Sikoglu, Elif M.; Jensen, J. Eric; Vitaliano, Gordana; Liso Navarro, Ana A.; Renshaw, Perry F.

    2013-01-01

    Background Research exploring Bipolar Disorder (BD) phenotypes and mitochondrial dysfunction, particularly in younger subjects, has been insufficient to date. Previous studies have found abnormal cerebral pH levels in adults with BD, which may be directly linked to abnormal mitochondrial activity. To date no such studies have been reported in children with BD. Methods Phosphorus Magnetic Resonance Spectroscopy (31P MRS) was used to determine pH, phopshocreatine (PCr) and inorganic phosphate (Pi) levels in 8 subjects with BD and 8 healthy comparison subjects (HCS) ages 11 to 20 years old. Results There was no significant difference in pH between the patients and HCS. However, frontal pH values for patients with BD increased with age, contrary to studies of HCS and the pH values in the frontal lobe correlated negatively with the YMRS values. Global Pi was significantly lower in subjects with BD compared with HCS. There were no significant differences in PCr between the groups. Global PCr-to-Pi ratio (PCr/Pi) was significantly higher in subjects with BD compared with HCS. Conclusions The change in Pi levels for the patients with BD coupled with the no difference in PCr levels, suggest an altered mitochondrial phosphorylation. However, our findings require further investigation of the underlying mechanisms with the notion that a mitochondrial dysfunction may manifest itself differently in children than that in adults. Limitations Further investigations with larger patient populations are necessary to draw further conclusions. PMID:23382910

  6. InP/ZnS nanocrystals: coupling NMR and XPS for fine surface and interface description.

    PubMed

    Virieux, Héloïse; Le Troedec, Marianne; Cros-Gagneux, Arnaud; Ojo, Wilfried-Solo; Delpech, Fabien; Nayral, Céline; Martinez, Hervé; Chaudret, Bruno

    2012-12-01

    Advanced (1)H, (13)C, and (31)P solution- and solid-state NMR studies combined with XPS were used to probe, at the molecular scale, the composition (of the core, the shell, and the interface) and the surface chemistry of InP/ZnS core/shell quantum dots prepared via a non-coordinating solvent strategy. The interface between the mismatched InP and ZnS phases is composed of an amorphous mixed oxide phase incorporating InPO(x) (with x = 3 and predominantly 4), In(2)O(3), and InO(y)(OH)(3-2y) (y = 0, 1). Thanks to the analysis of the underlying reaction mechanisms, we demonstrate that the oxidation of the upper part of the InP core is the consequence of oxidative conditions brought by decarboxylative coupling reactions (ketonization). These reactions occur during both the core preparation and the coating process, but according to different mechanisms. PMID:23131073

  7. Action of the multifunctional peptide BP100 on native biomembranes examined by solid-state NMR.

    PubMed

    Misiewicz, Julia; Afonin, Sergii; Grage, Stephan L; van den Berg, Jonas; Strandberg, Erik; Wadhwani, Parvesh; Ulrich, Anne S

    2015-04-01

    Membrane composition is a key factor that regulates the destructive activity of antimicrobial peptides and the non-leaky permeation of cell penetrating peptides in vivo. Hence, the choice of model membrane is a crucial aspect in NMR studies and should reflect the biological situation as closely as possible. Here, we explore the structure and dynamics of the short multifunctional peptide BP100 using a multinuclear solid-state NMR approach. The membrane alignment and mobility of this 11 amino acid peptide was studied in various synthetic lipid bilayers with different net charge, fluidity, and thickness, as well as in native biomembranes harvested from prokaryotic and eukaryotic cells. (19)F-NMR provided the high sensitivity and lack of natural abundance background that are necessary to observe a labelled peptide even in protoplast membranes from Micrococcus luteus and in erythrocyte ghosts. Six selectively (19)F-labeled BP100 analogues gave remarkably similar spectra in all of the macroscopically oriented membrane systems, which were studied under quasi-native conditions of ambient temperature and full hydration. This similarity suggests that BP100 has the same surface-bound helical structure and high mobility in the different biomembranes and model membranes alike, independent of charge, thickness or cholesterol content of the system. (31)P-NMR spectra of the phospholipid components did not indicate any bilayer perturbation, so the formation of toroidal wormholes or micellarization can be excluded as a mechanism of its antimicrobial or cell penetrating action. However, (2)H-NMR analysis of the acyl chain order parameter profiles showed that BP100 leads to considerable membrane thinning and thereby local destabilization.

  8. Cation substitution in β-tricalcium phosphate investigated using multi-nuclear, solid-state NMR

    SciTech Connect

    Grigg, Andrew T.; Mee, Martin; Mallinson, Phillip M.; Fong, Shirley K.; Gan, Zhehong; Dupree, Ray; Holland, Diane

    2014-04-01

    The substitution of aluminium, gallium and sodium cations into β-tricalcium phosphate (β-TCP; Ca{sub 3}(PO{sub 4}){sub 2}) has been investigated, and the Ca sites involved successfully determined, using a combination of 1D {sup 31}P, {sup 27}Al, {sup 71}Ga, {sup 23}Na and {sup 43}Ca (natural abundance) NMR and 2D {sup 27}Al({sup 31}P), {sup 71}Ga({sup 31}P) and {sup 23}Na({sup 31}P) rotary-resonance-recoupled heteronuclear multiple-quantum correlation (R{sup 3}-HMQC) NMR. Over the compositional range studied, substitution of Ca{sup 2+} by Al{sup 3+} or Ga{sup 3+} was observed only on the Ca(5) site, whilst substitution by Na{sup +} was confined to the Ca(4) site. Some AlPO{sub 4} or GaPO{sub 4} second phase was observed at the highest doping levels in the Al{sup 3+} and Ga{sup 3+} substituted samples. - Graphical abstract: 2D contour plots with skyline projections showing recoupling of {sup 27}Al, {sup 71}Ga and {sup 23}Na to different {sup 31}P sites. - Highlights: • β-Ca{sub 3}(PO{sub 4}){sub 2} has been prepared pure and also with Al{sup 3+}, Ga{sup 3+} and Na{sup +} substituents. • Multi-nuclear 1D NMR and heteronuclear X({sup 31}P) recoupling have been used. • Models for substitution correctly predict site preference and occupancy. • Progressive changes in {sup 31}P spectra have been explained. • Al{sup 3+} and Ga{sup 3+} substitute onto the Ca(5) site, and Na{sup +} onto the Ca(4) site.

  9. Structural analysis of the extracellular domain of vaccinia virus envelope protein, A27L, by NMR and CD spectroscopy.

    PubMed

    Lin, Ta-Hsien; Chia, Chih-Ming; Hsiao, Jye-Chian; Chang, Wen; Ku, Chiao-Chu; Hung, Shang-Cheng; Tzou, Der-Lii M

    2002-06-01

    This study presents the molecular structure of the extracellular domain of vaccinia virus envelope protein, A27L, determined by NMR and CD spectroscopy. A recombinant protein, eA27L-aa, containing this domain in which cysteines 71 and 72 were replaced with alanine, was constructed to prevent self-assembly due to intermolecular disulfide bonds between these two cysteines. The soluble eA27L-aa protein forms an oligomer resembling that of A27L on vaccinia virions. Heteronuclear correlation NMR spectroscopy was carried out on eA27L-aa in the presence or absence of urea to determine backbone resonance assignments. Chemical shift index (CSI) propensity analysis showed that eA27L-aa has two distinct structural domains, a relatively flexible 22-amino acid random coil in the N-terminal region and a fairly rigid alpha-helix structure in the remainder of the structure. Binding interaction studies using isothermal titration calorimetry suggest that a 12-amino acid lysine/arginine-rich segment in the N-terminal region is responsible for glycosaminoglycan binding. The rigid alpha-helix portion of eA27L-aa is probably involved in the intrinsic self-assembly, and CSI propensity analysis suggests that region N37-E49, with a residual alpha-helix tendency, is probably the self-assembly core. Self-assembly was ascribed to three hydrophobic leucine residues (Leu(41), Leu(45), and Leu(48)) in this segment. The folding mechanism of eA27L-aa was analyzed by CD spectroscopy, which revealed a two-step transition with a Gibbs free energy of 2.5 kcal/mol in the absence of urea. Based on these NMR and CD studies, a residue-specific molecular model of the extracellular domain of A27L is proposed. These studies on the molecular structure of eA27L-aa will help in understanding how vaccinia virus enters cells.

  10. Conformational analysis, UV-VIS, MESP, NLO and NMR studies of 6-methoxy-1,2,3,4-tetrahydronaphthalene.

    PubMed

    Arivazhagan, M; Kavitha, R; Subhasini, V P

    2014-07-15

    The detailed HF and B3LYP/6-311++G(d,p) comparative studies on the complete FT-IR and FT-Raman spectra of 6-methoxy-1,2,3,4-tetrahydronaphthalene [MTHN] have been studied. In view of the special properties and uses, the present investigation has been undertaken to provide a satisfactorily vibrational analysis of 6-methoxy-1,2,3,4-tetrahydronaphthalene. Therefore, a thorough Raman, IR, molecular electrostatic potential (MESP), non-linear optical (NLO) properties, UV-VIS, HOMO-LUMO and NMR spectroscopic investigation are reported complemented by B3LYP theoretical predictions with basis set 6-311++G(d,p) to provide novel insight on vibrational assignments and conformational stability of MTHN. Potential energy surface scans (PES) of the CH3 group are undertaken to shed light on the rather complicated conformational interchanges in the compound under investigation.

  11. Selective {sup 2}H and {sup 13}C labeling in NMR analysis of solution protein structure and dynamics

    SciTech Connect

    LeMaster, D.M.

    1994-12-01

    Preparation of samples bearing combined isotope enrichment patterns has played a central role in the recent advances in NMR analysis of proteins in solution. In particular, uniform {sup 13}C, {sup 15}N enrichment has made it possible to apply heteronuclear multidimensional correlation experiments for the mainchain assignments of proteins larger than 30 KDa. In contrast, selective labeling approaches can offer advantages in terms of the directedness of the information provided, such as chirality and residue type assignments, as well as through enhancements in resolution and sensitivity that result from editing the spectral complexity, the relaxation pathways and the scalar coupling networks. In addition, the combination of selective {sup 13}C and {sup 2}H enrichment can greatly facilitate the determination of heteronuclear relaxation behavior.

  12. Coal structure at reactive sites by sup 1 H- sup 13 C- sup 19 F double cross polarization (DCP)/MAS sup 13 C NMR spectroscopy

    SciTech Connect

    Hagaman, E.W.; Woody, M.C. )

    1989-01-01

    The solid state NMR technique, {sup 1}H-{sup 13}C-{sup 31}P double cross polarization (DCP)/MAS {sup 13}C-NMR spectroscopy, uses the direct dipolar interaction between {sup 13}C-{sup 31}P spin pairs in organophosphorus substances to identify the subset of carbons within a spherical volume element of 0.4 nm radius centered on the {sup 31}P atom. In combination with chemical manipulation of coals designed to introduce phosphorus containing functionality into the organic matrix, the NMR experiment becomes a method to examine selectively the carbon bonding network at the reactive sites in the coal. This approach generates a statistical structure description of the coal at the reaction centers in contrast to bulk carbon characterization using conventional {sup 1}H-{sup 13}C CP/MAS {sup 13}C NMR spectroscopy. 3 refs.