ABSTRACT
Lipopolysaccharide (LPS) was extracted from dry bacterial cells of plant-growth-promoting bacterium Azospirillum brasilense SR8 (IBPPM 5). The O-specific polysaccharide (OPS) was obtained by mild acid hydrolysis of the lipopolysaccharide and studied by sugar analysis, 1H and 13C NMR spectroscopy, including 1H,1H COSY, TOCSY, ROESY, and 1H,13C HSQC and HMBC experiments, computational NMR-based structure analysis, and Smith degradation. The OPS was shown to contain two types of repeating units of the following structure: Both OPS structures are present in A. brasilense 54, from which structure 1 has been reported earlier (Fedonenko et al., 2011), whereas to our knowledge structure 2 has not been hitherto found in bacterial saccharides. Treatment of wheat seedling roots with LPS of A. brasilense SR8 increased the number of root hair deformations as compared to seedlings grown without LPS, but had no effect on adsorption of the bacteria to the root surface. A. brasilense SR8 was able to utilize LPS of several structurally related Azospirillum strains.
Subject(s)
Azospirillum brasilense/chemistry , Lipopolysaccharides/chemistry , Lipopolysaccharides/pharmacology , O Antigens/chemistry , Triticum/physiology , Adsorption , Carbon-13 Magnetic Resonance Spectroscopy , Chemotaxis/drug effects , Lipopolysaccharides/isolation & purification , Plant Roots/drug effects , Plant Roots/physiology , Proton Magnetic Resonance Spectroscopy , Seedlings/drug effects , Seedlings/physiology , Triticum/drug effectsABSTRACT
The rhizobacteria Azospirillum brasilense Sp245 produce antigenically different lipopolysaccharides LPSI and LPSII, both containing identical pentasaccharides built from D-rhamnose residues as the repeated chains of O-specific oligosaccharides (OPS). In this study, we report the structure of the OPS from A. brasilense LPSI(-)LPSII(-)-mutant Sp245.5, which spontaneously lost the p85 and p120 plasmids upon the formation of a new 300-MDa megaplasmid after the long-term storage of the bacteria in a rich medium. The repeating unit of the A. brasilense mutant Sp245.5 appeared to be a disaccharide consisting of residues of N-acetyl-D-galactosamine and N-acetyl-D-mannosaminuronic acid: [Formula: see text].
Subject(s)
Azospirillum brasilense/genetics , O Antigens/chemistry , Azospirillum brasilense/chemistry , Magnetic Resonance Spectroscopy , Mutation , PlasmidsABSTRACT
The cell wall of Actinoplanes brasiliensis INA 3802 contains a teichuronic acid of unusual structure, as determined in a nondestructive way by 1H- and 13C-NMR spectroscopy. The polysaccharide comprises six tetrasaccharide units of the following composition: -->6)-alpha-D-Glcp-(1-->4)-beta-D-2,3-diacetamido- 2,3-dideoxyGlcpA-(1-->4)-alpha-D-2,3-diacetamido-2,3-dide oxyGlcp-(1-->4)-beta- D-2,3-diacetamido-2,3-dideoxyManpA. A polymer of such structure has not heretofore been reported for procaryotic cell walls.
Subject(s)
Actinomycetales/chemistry , Uronic Acids/isolation & purification , Carbohydrate Sequence , Cell Wall/chemistry , Magnetic Resonance Spectroscopy , Molecular Sequence Data , Uronic Acids/chemistryABSTRACT
The cell wall of Actinoplanes brasiliensis INA 3802 contains a polysaccharide which has an unusual structure. The peculiar structure of the polymer has been established by a nondestructive procedure which included 1H- and 13C-NMR spectroscopy. The polysaccharide consists of six tetrasaccharide links having the following composition -->6(alpha-D-Glc rho-(1-->4)-beta-D-Clc rho 2,3NAcA-(1-->4)-alpha-D-Clc rho 2,3NAc-(1-->4)-beta- D-Man rho 2,3NAcA-(1-->. No structurally identical polymer of the procaryotic cell wall has so far been reported.