THYMIDINE DIPHOSPHATE-L-RHAMNOSE METABOLISM IN SMOOTH AND ROUGH STRAINS OF ESCHERICHIA COLI AND SALMONELLA WESLACO.

Okazaki, Tuneko (Washington University School of Medicine, St. Louis, Mo.), Jack L. Stominger, and Reiji Okazaki. Thymidine diphosphate-l-rhamnose metabolism in smooth and rough strains of Escherichia coli and Salmonella weslaco. J. Bacteriol. 86:118-124. 1963.-Logarithmic-phase cells of Escherichia coli O18, which have rhamnose in their lipopolysaccharide, contained only traces of thymidine diphosphate (TDP)-l-rhamnose. Extracts of this organism, however, catalyzed the synthesis of TDP-l-rhamnose from TDP-d-glucose. On the other hand, cells of E. coli R44, a rough variant of this strain which contains no rhamnose in its lipopolysaccharide, contained a large amount of TDP-l-rhamnose. Like the smooth form, this organism was able to synthesize TDP-l-rhamnose. The rough variant is apparently a mutant blocked in some manner in utilization of TDP-l-rhamnose for lipopolysaccharide synthesis. Similar studies of smooth (rhamnose-containing) and rough (rhamnose-lacking) forms of Salmonella weslaco showed that both organisms can synthesize TDP-l-rhamnose from TDP-d-glucose. In contrast to the smooth and rough forms of E. coli O18, only traces of TDP-l-rhamnose were detected in extracts of both forms. A second thymidine diphosphosugar compound isolated from E. coli R44 is similar or identical to TDP-X, previously isolated from E. coli Y-10.