X-ray microanalysis of intracellular ions in the anaerobic halophilic eubacterium Haloanaerobium praevalens

Abstract

The intracellular concentrations of Na+, K+, and Cl− of the anaerobic halophilic eubacterium Haloanaerobium praevalens were assayed by means of X-ray microanalysis with the transmission electron microscope. Apparent intracellular cation concentrations between 1.22 and 1.91 M and chloride concentrations of 0.93–1.57 M were measured in cells growing exponentially in 2.6 M total salts. In exponentially growing cells, K+ was the major cation (70% of the cation sum). Stationary phase cells showed a high variability among individual cells, some of the cells containing higher Na+ than K+ concentrations.Key words: Haloanaerobium praevalens, intracellular ion concentrations, sodium, potassium, X-ray microanalysis.