Biosynthesis of glucuronosyl diglyceride by a cell‐free system obtained from a moderately halophilic‐halotolerant bacterium

Glucuronosyl digtyceride was recently isolated by Wilkinson from several species of the genus Pseudomonas and its structure was determined [1,2]. In a previous communication [3] we described the lipid composition of a moderately halophilic-halotolerant gram negative rod. These bacteria were found to contain a glucuronosyl diglyceride derivative which was different from that described by Wilkinson. When these bacteria were grown on a synthetic, high salt medium with glucose as sole carbon source, this lipid was the major glycolipid present; it amounted to 28% of the total polar lipids. In addition, small amounts of another glucuronic acid-containing glycolipid were found. This compound seems identical to the gtucuronosyl diglyceride of Wilkinson. From these bacteria, a cell-free preparation was obtained by sonication, which incorporated 14 C-labelled glucuronic acid added as UDP-glucuronic acid, and 14 C-labelled diglycerides into polar lipids. The properties of this system and the identification of the lipid formed will be described in this communication.