Relationship of the internal solute composition to the salt tolerance of Halomonas elongata

Abstract

The recently described genus Halomonas contains bacteria which are extremely tolerant to salt. The basis for this halotolerance was studied in cells grown in a chemically defined medium containing 0.05, 1.37, or 3.4 M NaCl. The organisms increase the intracellular concentration of sodium and calcium as well as glutamic acid and alanine as the concentration of NaCl in the growth medium increases. The data indicate that in high salt concentrations the osmotic pressure increase associated with those internal changes detected in this study does not balance the changes in the external osmotic pressure.