NUTRITION AND METABOLISM OF MARINE BACTERIA: IV. THE PARTICIPATION OF Na+, K+, AND Mg++SALTS IN THE OXIDATION OF EXOGENOUS SUBSTRATES BY A MARINE BACTERIUM

Abstract

The inorganic ion requirements for the preparation, storage, and oxidative activity toward exogenous substrates of washed cell suspensions of a marine bacterium have been investigated.Washing with distilled water greatly reduced the activity of cells toward exogenous substrates. There was found to be a relatively non-specific requirement for the presence of inorganic ions in the wash solution for the preparation of cell suspensions that are metabolically active when fresh.To maintain metabolic activity of the cells on storage, a specific requirement for Na⁺, K⁺, and Mg⁺⁺was demonstrated. In addition, Mg⁺⁺was active in preventing cytolysis. Mn⁺⁺could replace Mg⁺⁺in the latter capacity but not in some function of Mg⁺⁺connected with oxidative processes.For oxidation of exogenous substrates, a requirement for Na⁺and K⁺but not Mg⁺⁺was demonstrated. The optimum Na⁺concentration lay between 0.1 and 0.3 M and K⁺between 0.01 and 0.1 M.