Lipopolysaccharides were isolated from the phenol layer on aqueous phenol extraction of cells of Pseudomonas aeruginosa 011 (Lanyi classification), strains 170021 and 170040. On mild acid degradation of the lipopolysaccharides, with the subsequent gel-filtration on Sephadex G-50, neutral 0-specific polysaccharides made up of 6-deoxysugars alone were obtained. Two 2-acetamido-2,6-dideoxy-~-galactose (LFucNAc), 2-acetamido-2,6-dideoxy-D-glucose (DQuiNAc) and L-rhamnose (LRha) residues were found to be the components of the strain 170021 polysaccharide repeating units; those of strain 170040 contained the same monosaccharides, but, instead of 2-acetamido-2,6-dideoxy-~-glucose residue, that of 2-acetamido-2,6-dideoxy-~-galactose (DFucNAc) was present.On the basis of the I3C nuclear magnetic resonance data, methylation analysis and three successive Smith degradations the following structures were determined for the polysaccharide repeating units: strain 170021, +2)~Rha(al-+3)~FucNAc(ctl+3)~FucNAc(al+3)~QuiNAc(~1+ ; strain 170040, -+2)~Rha(al-t3)~FucNAc- More recent studies demonstrated a serological interrelationship between strain 170021 and serologically nonidentical to it strain 170040; in the new Lanyi and Bergan classification both of these strains were placed into one 0-serogroup and designated as serotypes 04a, b and 04a, c, respectively [l].In the present communication structures of the repeating units of the 0-specific polysaccharide of P. aeruginosa, strains 170021 and 170040, were established, and, on the basis of a marked structural similarity, the fact of their reference to the same 0-serogroup in the classification [l] was justified.
MATERIALS AND METHODS
Miscellaneous methodsInfrared spectra were measured with a UR-10 Karl Zeiss spectrometer in potassium bromide pellets. 'H and I3C nuclear magnetic resonance spectra were recorded with a WM- 250 (Bruker) instrument in D 2 0 at 60°C for polysaccharides and at 30 "C for oligosaccharides; chemical shifts are given from tetramethylsilane using as an internal standard acetone (6, = 2.23 ppm) or methanol (6, = 50.15 ppm).Optical rotations were determined with a Perkin-Elmer polarimeter, model 141, in water at 20°C. Solutions were freeze-dried or evaporated in vucuo at 40°C. Serological tests were conducted as described earlier [4].
Chromatography and electrophoresisAscending paper chromatography was carried out on Whatman paper in the system ethyl acetate/pyridine/water/ acetic acid (5/5/3/1, by vol.). Paper electrophoresis was performed in 0.025 M pyridine/acetate buffer, pH 4.5, at 28 V/cm. Alkaline silver nitrate reagent or ninhydrin solution were used to detect substances on paper.Gel-filtration was run on columns with Sephadex G-50 (67 x 3.3 cm or 38 x 1.3 cm) and Sephadex G-15 (87 x 1.4 cm). Gas-liquid chromatography was conducted on a Pye Unicam instrument series 104 (model 64), on a glass column (150x0.4cm) with 3% OV-1 on Diatomite CQ (100-200 mesh) ; carrier gas nitrogen. Gas-liquid chromatography/ mass spectrometry was performed on a Varian MAT 111...