title: Intracellular pH of Thermoplasma acidophila.
abstract: Thermoplasma acidophila, a mycoplasma-like organism, was grown at 56 degrees C and pH 2. The intracellular pH of this organism is close to neutral as measured by the distribution of a radioactive weak organic acid, 5,5-dimethyl-2,4-oxazolidinedione, across the plasma membrane. The cell can maintain the pH gradient when subjected to heat or to metabolic inhibitors. Our experiments seem to indicate that a major portion of the pH gradient is not maintained by active processes, but rather by a Donnan potential across the cell membrane.
mesh_terms: D001692:Biological Transport; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008291:Malate Dehydrogenase / Q000378:metabolism; D008433:Mathematics; D009174:Mycoplasma / Q000378:metabolism*; D010080:Oxazoles / Q000378:metabolism
chemical_list: D010080:Oxazoles; D008291:Malate Dehydrogenase