scholarly journals Intracellular pH in Dictyostelium discoideum: a 31P nuclear magnetic resonance study.

1985 ◽  
Vol 101 (3) ◽  
pp. 778-784 ◽  
Author(s):  
J E Jentoft ◽  
C D Town
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Dictyostelium Discoideum ◽  
Intracellular Ph ◽  
Nuclear Magnetic Resonance Study ◽  
Published Data ◽  
Cellular Slime Mold ◽  
Ph Homeostasis ◽  
Cytosolic Ph ◽  
Nuclear Magnetic

We have used phosphorus-31 nuclear magnetic resonance to determine intracellular pH in the cellular slime mold Dictyostelium discoideum. We devised an air-lift circulator to maintain the dense cell suspensions in a well-oxygenated and well-stirred state while causing minimal perturbation to the sample flowing through the detector coils. Cells continued to develop normally in this set-up. Spectra acquired under these conditions typically show two peaks in the inorganic phosphate region corresponding to pH values of 7.16 +/- 0.03 and 6.48 +/- 0.02. These peaks are believed to represent the mitochondrial and cytosolic compartments respectively, based on a comparison of these values with published data and the collapse of the two compartments upon addition of the mitochondrial uncoupler carbonyl cyanide 4-(trifluoromethoxy)-phenylhydrazone. Dictyostelium cells show a remarkable degree of intracellular pH homeostasis. Both mitochondrial and cytosolic pH remained unchanged as extracellular pH was varied from 4.3 to 8.1. There was also no apparent change in the pH of either compartment after up to 13.5 hours' development in suspension.

scholarly journals Nuclear magnetic resonance study of sea-water freezing mechanisms: 1. Temperature dependence of relative brine content in sea ice

2013 ◽  
Vol 59 (216) ◽  
pp. 711-718 ◽  
Author(s):  
N.A. Mel’nichenko ◽  
A.B. Slobodyuk
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Temperature Dependence ◽  
Sea Water ◽  
Nuclear Magnetic Resonance Study ◽  
Crystalline Hydrate ◽  
Published Data ◽  
Experimental Conditions ◽  
Brine Salinity ◽  
Nuclear Magnetic

AbstractThe results of measuring relative brine content (Qlm) in the liquid phase of frozen sea water at temperatures between −2°C and −43°C with variable rate and direction of temperature change are presented. Various pulsed and steady-state nuclear magnetic resonance (NMR) methods are used and the results are compared with data in the literature. Temperature dependences of Qlm in sea water with dry NaCl added are given. Quasi-hysteresis corresponding to the crystallization range of certain seawater salts, mainly NaCl, which partially precipitates as the crystalline hydrate NaCl·2H2O at temperatures below −23°C, is detected in the temperature dependence of Qlm. The reasons why Qlm values, under various experimental conditions, differ from data in the literature are explained. Brine salinity (S) is calculated from the relative intensity of NMR signals of Ql, and agrees well with previously published data over a wide temperature range. It is shown that determining Qlm from base measurements of Ql in ice does not require information about brine salinity. Empirical equations for calculating brine content at different sea-water temperatures and salinity are given.

scholarly journals A 31P Nuclear Magnetic Resonance Study of Intracellular pH of Plant Cells Cultivated in Liquid Medium

1982 ◽  
Vol 70 (4) ◽  
pp. 1156-1161 ◽  
Author(s):  
Jean-Baptiste Martin ◽  
Richard Bligny ◽  
Fabrice Rebeille ◽  
Roland Douce ◽  
Jean-Jacques Leguay ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Liquid Medium ◽  
Intracellular Ph ◽  
Plant Cells ◽  
Nuclear Magnetic Resonance Study ◽  
Magnetic Resonance Study ◽  
31P Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

scholarly journals Cerebral Intracellular Changes during Supercarbia: An in vivo 31P Nuclear Magnetic Resonance Study in Rats

1985 ◽  
Vol 5 (4) ◽  
pp. 537-544 ◽  
Author(s):  
Lawrence Litt ◽  
Ricardo González-Méndez ◽  
John W. Severinghaus ◽  
William K. Hamilton ◽  
Julia Shuleshko ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Intracellular Ph ◽  
Nuclear Magnetic Resonance Study ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Fourfold Increase ◽  
Control Value ◽  
Nuclear Magnetic

31P nuclear magnetic resonance (NMR) spectroscopy was used noninvasively to measure in vivo changes in intracellular pH and intracellular phosphate metabolites in the brains of rats during supercarbia (Paco2 ⩾ 400 mm Hg). Five intubated rats were mechanically ventilated with inspired gas mixtures containing 70% CO2 and 30% O2. Supercarbia in the rat was observed to cause a greater reduction in cerebral intracellular pH (pHi) and increase in Pco2 than observed in other experiments with rats after 15 min of global ischemia. Complete neurologic and metabolic recovery was observed in these animals, despite an average decrease in pH; of 0.63 ± 0.02 pH unit during supercarbia episodes that raised Paco2 to 490 ± 80 mm Hg. No change was observed in cerebral intracellular ATP and only a 25% decrease was detected in phosphocreatine. The concentration of free cerebral intracellular ADP, which can be calculated if one assumes that the creatine kinase reaction is in equilibrium, decreased to approximately one-third of its control value. The calculated threefold decrease in the concentration of free ADP and twofold increase in the cytosolic phosphorylation potential suggest that there is increased intracellular oxygenation during supercarbia. Because a more than fourfold increase in intracellular hydrogen ion concentration was tolerated without apparent clinical injury, we conclude that so long as adequate tissue oxygenation and perfusion are maintained, a severe decrease in intracellular pH need not induce or indicate brain injury.

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