Chemical analysis of Azospirillum lipopolysaccharides

Lipopolysaccharides (LPS) were extracted by hot phenol-water from five strains each of Azospirillum lipoferum and Azospirillum brasilense. Rhamnose, glucose, glucosamine and 3-deoxy-d-mannooctulosonic acid were comon sugar constituents of all LPS preparations. 2-O-Mefucose, 3-O-Me-fucose, 3-O-Me-rhamnose and 2-O-Megalactose were found in LPSs of some A. brasilense strains. Fatty acid spectra from all LPSs studied were almost identical with predominance of 3-hydroxymyristic and 3-hydroxypalmitic acids. 3-Hydroxypalmitic acid was the only amide-linked fatty acid. Lipopolysaccharides isolated from A. brasilense showed higher heterogeneity in sugar composition than those from A. lipoferum.Abbreviations glc gas liquid chromatography - ms mass spectrometry - LPS lipopolysaccharide - dOclA 3-deoxy-d-mannooctulosonic acid - 3-OH-16:0 3-hydroxypalmitic acid - nir^- nitrite reductase negative - nir⁺ nitrite reductase positive