Pseudomonas ji'uorescens is a phenotypically heterogeneous microorganism divided into five biovars having undefined taxonomical rank. No serological classification has been elaborated for strains of this bacterium. In our studies of cell-wall lipopolysaccharides of P. fluorescens, we have established [l] the structure of the O-specific polysaccaride of biovar A strain IMV 1152. Now we report the structure of the O-specific polysaccharide chain of the lipopolysaccharide of strain IMV 472 belonging to the same biovar A.
The lipopolysaccharide of strain IMV 472 was isolated by the phenol-water procedure [2] and cleaved with dilute acetic acid as described [3], to give the O-specific polysaccharide.
The 13C NMR spectrum of the polysaccharide (Table 1) contained signals for four anomeric carbons at 97.6, 100.8, 102.5, and 103.8 ppm, one carbon bearing nitrogen at 57.0 ppm, three CH,-C groups (C-6 of 6-deoxy sugars) at 16.3, 17.8, and 18.1 ppm, other sugar carbons in the region 67.7-84.7 ppm, one NAc group (CH, at 23.8 ppm, CO at 176.1 ppm), and one OAc group (CH, at 22.0 ppm, CO at 174.1 ppm).
Therefore, the polysaccharide has a tetrasaccharide repeating unit, which contains three residues of 6-deoxy sugars and one residue of an N-acetylated amino sugar.