STUDIES ON BACTERIAL UTILIZATION OF URONIC ACIDS III

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Abstract
Resting cells of a marine pseudomonad, induced in culture to galacturonate utilization and washed with sea water, oxidized glucuronate initially at 50% of the rate of galacturonate. After an incubation of 2 hours, the rate of oxidation of glucuronate increased to approximately 3 times that of galacturonate. Cells grown on glucuronate did not oxidize galacturonate. Induction of glucuronate oxidation in resting cells grown in sea water nutrient broth, washed with sea water, and suspended in sea salt water was inhibited by dilution of the sea salt water. Addition of sea salt to cells incubated with substrate in distilled water enabled induction to occur. Washing with 0.052 [image] MgCl2 provided cells which were inducible to significant activity in neutralized sea water and, to lesser degrees, in solutions of Na, K, and Mg salts. NaCl and KC1 are indispensable to the cells for induction and activity. Supplementing solutions of these salts with MgCl2 and MgSO4 increased the rates of induction and oxidation. In experiments in which cells were preincubated with substrate in solutions of single salts, the dependence of induction on Na+ and of oxidation on K+ was demonstrated. Oxidation of glucuronate by resting cells grown on that substance was linear from the time the substrate was added only in systems containing K+.