During antidiuresis, renal papillary cells accumulate organic osmolytes preferentially over inorganic ions. It has been previously demonstrated that sodium infusion increased all of these organic osmolytes except myo-inositol (1). Conversely, urea infusion increased only glycerophosphorylcholine significantly. In addition to sodium and urea, potassium localized in tissue and urine influenced th...

BACKGROUND AND AIMS Osmolytes are low-molecular-weight organic solutes, a broad group that encompasses a variety of compounds such as amino acids, tertiary sulphonium and quaternary ammonium compounds, sugars and polyhydric alcohols. Osmolytes are accumulated in the cytoplasm of halophytic species in order to balance the osmotic potential of the Na(+) and Cl(-) accumulated in the vacuole. The a...

Cells of many organisms accumulate certain small organic molecules--called compatible and counteracting solutes, compensatory solutes, or chemical chaperones--in response to certain physical stresses. These solutes include certain carbohydrates, amino acids, methylamine and methylsulphonium zwitterions, and urea. In osmotic dehydrating stress, these solutes serve as cellular osmolytes. Unlike c...

Dialysis disequilibrium syndrome (DDS) is characterized by the neurologic deterioration and cerebral edema that occurs after hemodialysis. To investigate the pathogenesis of DDS, the effects of rapid hemodialysis on brain electrolytes, urea, and several organic osmolytes were studied in the rat. Forty-two h after bilateral ureteral ligation, 11 uremic rats were hemodialyzed for 90 min, yielding...

Cells subjected to sustained high osmolarity almost universally respond by accumulating compatible organic osmolytes that, in contrast to inorganic ions, are not deleterious even at high intracellular concentrations. Their accumulation from the external environment by known organic osmolyte transporters, such as the four identified in mammals, occurs only slowly in response to sustained high os...

The response of archaea to changes in external NaCl is reviewed and compared to what is known about osmoadaptation and osmoregulation in bacteria and eukaryotes. Cells placed in altered external NaCl exhibit short term and long term responses. The earliest events are likely to be water movement through aquaporin-like channels (efflux if external NaCl has been increased, influx into the cell if ...

We present a study on the influence of the naturally occurring organic osmolytes tri-methylamine N-oxide (TMAO) and urea on the bulk structure of water using X-ray Raman scattering spectroscopy. Addition of TMAO is known to stabilize proteins in otherwise destabilizing aqueous urea solutions. The experimental X-ray Raman scattering spectra change systematically with increasing solute concentrat...

Protein solvation is the key determinant for isothermal, concentration-dependent effects on protein equilibria, such as folding. The required solvation information can be extracted from experimental thermodynamic data using Kirkwood-Buff theory. Here we derive and discuss general properties of proteins and osmolytes that are pertinent to their biochemical behavior. We find that hydration depend...

Osmolytes are low molecular weight organic molecules accumulated by organisms to assist proper protein folding, and to provide protection to the structural integrity of proteins under denaturing stress conditions. It is known that osmolyte-induced protein folding is brought by unfavorable interaction of osmolytes with the denatured/unfolded states. The interaction of osmolyte with the native st...