Isolation and structure elucidation of two different polysaccharides from the lipopolysaccharide of Rahnella aquatilis 33071T. Carbohydr Res
N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospeckt 47, 119991 Moscow, Russia.Carbohydrate research (Impact Factor: 1.93). 05/2009; 344(10):1259-62. DOI: 10.1016/j.carres.2009.04.013
Two different polysaccharides were obtained by mild acid degradation of the lipopolysaccharide of Rahnella aquatilis 33071(T). These were studied by sugar and methylation analyses along with 1D and 2D (1)H and (13)C NMR spectroscopy. The following structures were established for the polysaccharides: -->4)-alpha-D-Rhap-(1-->3)-alpha-D-Rhap-(1-->3)beta-D-Galp-(1-->3)-alpha-D-Manp-(1-->2)-alpha-D-Manp-(1--> beta-D-Glcp-(1-->3)-alpha-D-galp-(1-->4)-alpha-D-GlcpA-(1-->2). The former structure is new, whereas the latter has been reported earlier as the structure of the O-specific polysaccharide of R. aquatilis 95 U003 (Zdorovenko, E. L.; Varbanets, L. D.; Zatonsky, G. V.; Kachala, V. V.; Zdorovenko, G. M.; Shashkov, A. S.; Knirel, Y. A. Carbohydr. Res.2008, 343, 2494-2497).
Chapter: Structure of O-Antigens[Show abstract] [Hide abstract]
ABSTRACT: The lipopolysaccharide (LPS) is the major constituent of the outer leaflet of the outer membrane of Gram-negative bacteria. Its lipid A moiety is embedded in the membrane and serves as an anchor for the rest of the LPS molecule. The outermost repetitive glycan region of the LPS is linked to the lipid A through a core oligosaccharide (OS), and is designated as the O-specific polysaccharide (O-polysaccharide, OPS) or O-antigen. The O-antigen is the most variable portion of the LPS and provides serological specificity, which is used for bacterial serotyping. The OPS also provides protection to the microorganisms from host defenses such as complement mediated killing and phagocytosis, and is involved in interactions of bacteria with plants and bacteriophages. Studies of the OPSs ranging from the elucidation of their chemical structures and conformations to their biological and physico-chemical properties help improving classification schemes of Gram-negative bacteria. Furthermore, these studies contributed to a better understanding of the mechanisms of pathogenesis of infectious diseases, as well as provided information to develop novel vaccines and diagnostic reagents.
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ABSTRACT: A lipopolysaccharide (LPS) from Budvicia aquatica DRL 20186 was isolated, studied, and chemically identified. It was shown to be lowly toxic, but highly pyrogenic. Its fatty acid composition was similar to that of the LPS from other Enterobacteriaceae, with predominance of tetradecanoic (32.7%) and 3-hydroxytetradecanoic acids (23.8%). Hexadecenoic (20.4%), hexadecanoic (11.8%), and dodecanoic acids (8.4%) were also revealed. Double immunodiffusion in agar by the Ouchterlony method revealed antigenic activity of the B. aquatica DLR 20186 LPS in a homologous system. In cross reactions, however, it did not interact with the antisera of other B. aquatica strains.
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ABSTRACT: A neutral heteropolysaccharide (PCIPS2) was isolated and purified from mycelium of Paecilomyces cicadae, which was investigated to be mainly composed of d-mannose, l-rhamnose, 3-O-methyl-d-galactose, d-glucose and d-galactose with a molar ratio of 47.9:3.1:6.4:0.9:0.8. It had a backbone of 1,4-linked α-l-Rhap residues and 1,6-linked α-d-Manp residues with branches at O-3 of α-d-Manp residues. Its side chain was comprised of minor terminal β-d-glucose and 1,4-linked α-3-O-Me-d-Galp residues terminated by α-d-galactose. Furthermore, its chain information on the values of weight-average molar mass (Mw), root mean square radius ('S2'z1/2), hydrodynamic radius (Rh) and intrinsic viscosity ([η]) for PCIPS2 were analyzed to be 3.09 × 104 g/mol, 7.8 nm, 3.6 nm and 8.5 mL/g, respectively. The structural exponent α of 0.57 indicated that PCIPS2 existed as a flexible chain conformation with a coil-like structure in 0.1 M NaNO3 at 25°C. In terms of known theory for worm-like chains, the model parameters for PCIPS2 were as following: molar mass per unit contour length (ML) = 379 nm-1, persistence length (q) = 0.74 nm and hydrodynamic diameter of cylinder (d) = 0.82 nm, which were further evidenced by atomic force microscopy (AFM).
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