Nuclear magnetic resonance studies of cesium-133 in the halophilic halotolerant bacterium Ba1. Chemical shift and transport studies

Biomedical applications of133Cs NMR

“…The term 'non-ideality,' in reference to intracellular water, refers to the idea that the hydrogen bonding network among water molecules, and thus the 'structure' of water, inside the cell is markedly different than that of 'ideal' water ('ideal' water refers to water found in the pure state or in dilute aqueous solutions). It has been suggested that the non-ideality of water results from the high concentration of solute inside cells, 12,32,33 such as hemoglobin in erythrocytes. It is expected that, as the number of solvated species increases, so does the fraction of water that comprises the various spheres of hydration for these solutes.…”

“…In the in vivo setting, Sakhnini et al 12 and Gilboa et al 13 studied the 133 Cs chemical shift of Cs þ under the conditions of extremely high salt concentrations using the halophilic halotolerant bacterium Ba 1 . These cells, which can be found in the Dead Sea, tolerate extremely high concentrations of salt.…”

“…133 Cs þ and 87 Rb þ , the other K þ analog, are both much more sensitive to the NMR experiment than is 39 K, whose NMR receptivity is roughly 100 times less than that of the two analogs. 5 133 Cs þ accumulates in the intracellular space 6,7 primarily by the action of the Na þ -K þ pump, 2,3,[6][7][8][9][10][11][12][13] and has a transmembrane permeability of 0.1-0.2 of that of K þ . Rubidium has a transmembrane permeability that is roughly equivalent to that of K þ , [14][15][16] perhaps because the ionic radius of Rb þ (148 pm) is more similar to K þ (133 pm) than is that of Cs þ (167 pm).…”

Cs + ADC in rat brain decreases markedly at death

“…133 Cs is much more readily detected by MR methods than is 39 K, whose MR receptivity is roughly 100 times less than that of 133 Cs (12). Cesium accumulates in the intracellular space, primarily by the action of the Na + ‐K + pump (9, 10, 13–20). Cs + has a transmembrane resting transport/permeability of 0.1 to 0.3 of that of K + (9, 21), thus Cs + efflux from energy depleted cells is considerably slower than that of K + .…”

“…Furthermore, the Cs + ion is highly polarizable, which makes its chemical shift sensitive to its local environment (22). As a result, intracellular 133 Cs has a different chemical shift than extracellular 133 Cs (9–11, 19, 20, 23–25). Thus, 133 Cs NMR can be used to spectroscopically resolve Cs in the extracellular and intracellular compartments without the use of exogenous shift reagent.…”