A RAPID METHOD FOR SUGAR ANALYSIS OF LIPOPOLYSACCHARIDES OF GRAM-NEGATIVE BACTERIA

A simple and rapid method was developed for preparing and analysing the “degraded polysaccharide” (DPS) fraction virtually corresponding to the polysaccharide portion of lipopolysaccharides (LPS) from cells of Gram-negative bacteria without separating LPS. Salmonella typhimurium LT2 was used as a standard for establishing the method. It was successfully applied not only to S. typhimurium but also to Escherichia coli, Shigella flexneri, Yersinia enterocolitica, Plesiomonas shigelloides, O1 and non-O1 Vibrio cholerae, Vibrio fluvialis, Vibrio vulnificus and Vibrio anguillarum. The sugar composition of the samples prepared directly from the cells of each of these strains by the rapid method and that of the DPS fraction isolated from LPS prepared by Westphal's standard phenol-water technique was shown to be identical. However, in the case of O1 and non-O1 V. cholerae and the other three vibrio species, 2-keto-3-deoxyoctonate (KDO) was undetectable by the conventional colour test (Weissbach's reaction) under conventional hydrolysis conditions. In spite of this limitation, the rapid method is considered to be suitable to determine the sugar composition of the polysaccharide portion of LPS of Gram-negative bacteria with chemotaxonomic studies. © 1990, Gustav Fischer Verlag, Stuttgart · New York. All rights reserved.