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

Abstract

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.