Resolution 31P Nuclear Magnetic Resonance Research Articles

High resolution 31P nuclear magnetic resonance study of Cr3+-doping effects on KTiOPO4

P nuclear magnetic resonance was employed to investigate Cr 3þ -doping effects on KTiOPO4. The high resolution 31 P isotropic chemical shift and linewidth measurements sensitively revealed changes in the microscopic environments caused by the doping.

Phospholipid synthesis in the lymphomatous mouse liver studied by 31P nuclear magnetic resistance spectroscopy in vitro and by administration of 14C-radiolabelled compounds in vivo

High phosphomonoester to ATP ratios have been found in 31P magnetic resonance spectra from livers of patients with hepatic lymphoma (Dixon et al. (1990) Br. J. Cancer 63, 953–958). The present study of a murine lymphoma showed that the phosphomonoester in the lymphomatous liver was largely phosphoethanolamine, which is an intermediate of phospholipid metabolism. A significant positive correlation was found between the concentration of phosphoethanolamine, measured by high resolution 31P nuclear magnetic resonance spectroscopy of extracts, and the degree of infiltration, assessed by quantitative histology. The phosphoethanolamine concentration reached about 10 times its normal level, but the phosphocholine concentration remained the same as in the normal liver. Radiolabelling studies showed that while the rate of phosphoethanolamine synthesis from exogenous [ 14]ethanolamine was higher in the lymphomatous mouse liver than in control livers, the rate of phosphatidylethanolamine synthesis was lower in the lymphomatous liver. The rate of phosphatidylcholine synthesis in lymphoma-bearing livers was not significantly different from that in control mouse livers.

31P NMR of tissue phospholipids: competition for Mg2+, Ca2+, Na+ and K+ cations.

Phosphatidylcholine (PC), phosphatidylethanolamine (PE), ethanolamine plasmalogen (EPLAS), sphingomyelin (SPH), phosphatidylinositol (PI), phosphatidylserine (PS), cardiolipin (CL), phosphatidylglycerol (PG) and phosphatidic acid (PA) were dispersed together in Cs(ethylenedinitrilo)tetraacetic acid-scrubbed chloroform/methanol solution, and high resolution 31P nuclear magnetic resonance spectra were recorded. In separate titration experiments, Mg2+ and Ca2+ were added to the dispersed phospholipid mixture to determine the relative interaction potentials of each of the phospholipids for each of the added cations. The association of cations with individual phospholipids was indicated by 31P chemical-shift changes, signal broadening, signal quenching or a combination of these. The titrations revealed that CL had the highest, and PA the next highest, interaction potential for Mg2+ cations. In contrast, PS and PA had the highest, and CL the next highest, interaction potential for Ca2+. Considering only interactions with Ca2+ ions, the phospholipids can be divided into three distinct groups: PS and PA (high interaction potential); CL, PI and PG (intermediate interaction potential); and EPLAS, PE, SPH and PC (essentially no interaction potential). The two phospholipids with the least interaction potential for either of the alkaline-earth cations were PC and SPH. Na+ and K+ ion interactions with PA, CL, PI and PG were unique and resulted in positive chemical-shift changes relative to the chemical shifts in the presence of Cs+ ions. Relative to both Cs+ and K+ ions, chemical shifts in the presence of Na+ ions were deshielded delta greater than 0.1 ppm in the order PA greater than CL greater than PI greater than PG.

Phosphorus nuclear magnetic resonance of diverse phosvitin species

1. 1. High resolution 31P nuclear magnetic resonance (NMR) spectra, with and without proton decoupling, of the principal egg phosphoproteins—phosvitins—of a bird ( Gallus gallus), an amphibian ( Xenopus laevis) and a fish ( Salmo gairdneri) were obtained. 2. 2. The spectra were evaluated with special reference to available amino acid sequences and the major NMR resonance in all three spectra was assigned to phosphoserine clusters. 3. 3. The resolution of numerous additional phosphorus resonances provides the basis for further investigation of the particular molecular environments of phosvitin-bound phosphoryl groups and their involvement in the diverse binding modes for metal complex formation by phosvitins.

Characterization of the 31P NMR spectrum of Manduca sexta and effects of antimetabolites

High resolution 31P nuclear magnetic resonance spectroscopy (NMR) was successfully applied to 5th instar larvae of Manduca sexta. Conditions for in vivo analysis under non-saturating conditions are described. The 31P NMR spectrum of intact larvae was composed of six peaks. Their resonance frequencies are reported relative to orthophosphoric acid. Analysis of tissue extracts demonstrated the in vivo peaks to be composed of the β phosphorus resonance of nucleotide triphosphates (NTP) at −19.36 ppm; α phosphorus of NTP and nucleotide diphosphates (NDP) at −10.51 ppm; β and γ phosphorus of NDP and NTP, respectively, at −5.42 ppm; phosphoarginine (PA) at −3.45 ppm; inorganic phosphate (Pi) at +2.76 ppm and sugar phosphates at +3.34 ppm. The major sugar phosphate present in fat body extracts was trehalose-6-phosphate and this was the major phosphorus component of the spectrum of hemolymph. The spin-lattice relaxation times for each in vivo peak were determined. Titration of aqueous fat body and hemolymph extracts was carried out and the relationship between the chemical shift of Pi and pH determined. On this basis the pH of the hemolymph was estimated at approx. 6.7. The metabolic inhibitors, iodoacetate and dinitrophenol, had significant effects on the 31P NMR spectrum of intact larvae. Administration of iodoacetate caused a rapid increase in the levels of sugar phosphates together with decreases in NTP and PA. Dinitrophenol also caused declines in the relative levels of NTP and PA but sugar phosphates decreased as well. The experiments demonstrated the potential of in vivo NMR analysis for metabolic studies on high energy phosphate metabolites in M. sexta.

Acute pancreatitis in rats: A 31P nuclear magnetic resonance study

High resolution 31P nuclear magnetic resonance (NMR) was used to evaluate the severity of acute pancreatitis in rats. Experimental pancreatitis was induced by intraparenchymal injection of 10% sodium taurocholate. Pancreases were removed at various time periods and the NMR spectrum of the whole organ was recorded. Metabolic changes taking place during the progression of the disease were measured and correlated with the pathologic changes. Gradual depletion of the high energy compounds, adenosine triphosphate and phosphocreatine, was observed. The NMR spectral changes paralleled the extension of the pathologic lesions and were found to constitute a reliable indicator of the severity of acute pancreatitis. It is suggested that high resolution NMR may be used to evaluate the pathogenesis and therapy of various forms of experimental pancreatitis.

In vivo 31P nuclear magnetic resonance measurements in canine heart using a catheter-coil.

We have developed a new method of obtaining high resolution 31P nuclear magnetic resonance spectra from canine heart without the need for major surgery. This is done by passing an elliptical nuclear magnetic resonance receiver coil through a peripheral blood vessel into the right or left ventricle. This technique enables spectra to be obtained from a defined region of myocardium in less than 7 minutes (for the right ventricle) with a signal:noise ratio of greater than 9:1. With this catheter-coil, useful cardiac metabolic information will be obtainable, not only from specified regions of the heart, but also from various layers of myocardium.

31P nuclear magnetic resonance studies of the fermentation of glucose to ethanol by Zymomonas mobilis.

High resolution 31P nuclear magnetic resonance spectroscopy has been employed to study the fermentation of glucose to ethanol by Zymomonas mobilis, strain ZM4, a bacterium which uses the Entner-Doudoroff pathway. The levels of nucleoside triphosphates, sugar phosphates, UDP-sugars and Pi in intact fermenting cells have been studied with a time resolution of 1 min. It is suggested that a pH gradient is established across the cell membrane during fermentation and that the intracellular pH does not rise above approximately 6.4. 31P resonances from most phosphorus-containing intermediates in the Entner-Doudoroff pathway, as well as adenosine and uridine nucleotides and a number of other intracellular metabolites, have been assigned in perchloric extracts of fermenting cells by means of a number of techniques, including two-dimensional homonuclear J-resolved and two-dimensional homonuclear shift-correlated spectroscopy. Quantification of these metabolites in spectra of extracts of fermenting cells indicates that the rate-limiting steps in the Entner-Doudoroff pathway in Z. mobilis are the conversions of glucose 6-phosphate to 6-phosphogluconate and of 3-phosphoglycerate to 2-phosphoglycerate.

High resolution 31P nuclear magnetic resonance studies of intact yeast cells.

High resolution 31P nuclear magnetic resonance (NMR) spectra at 145.7 MHZ are presented for intact yeast cells. Several peaks are resolved and assigned. They include the middle phosphate peaks from long chain or cyclic polyphosphates. Our results are consistent with the suggestion that these polyphosphates act as a phosphate store in the cell. We have also been able to measure cytoplasmic pH using the orthophosphate peak inside the cell, as compared with outside the cell. The results show that yeast cells maintain their cytoplasmic pH around 6.3. This value is considerably higher than the acidic extracellular pH at which they normally live. These preliminary results indicate that 31P NMR at 145.7 MHZ can be a rapid, informative, and non-invasive method for probing biochemical events within living cells.