Lipopoly saccharides

A structural study on lipid A and the O-specific polysaccharide of the lipopoly-saccharide from a clinical isolate of Bacteroides vulgatus from a patient with Crohn s disease was conducted by Hashimoto and coworkers [39]. They separated two potent virulence factors, capsular polysaccharide (CPS) and lipopolysaccharide (LPS), from a clinical isolate of B. vulgatus and characterized the structure of CPS. Next, they elucidated the strucmres of O-antigen polysaccharide (OPS) and lipid A in the LPS. LPS was subjected to weak acid hydrolysis to produce the lipid A fraction and polysaccharide fraction. Lipid A was isolated by PLC, and its structure was determined by MS and NMR. 

The high space-time yields are the result of a doubling time of only 30 min and its applicability for high cell-density cultures. However, it is hardly possible to excrete overexpressed proteins into cultivation media. In addition, accumulation of pyrogenic lipopoly-saccharides in its outer membrane (a distinctive feature of Gram-negative bacteria) make additional purification steps necessary if pharmaceutical proteins are produced by E. coli [29]. 

Hewett, J. A. and Roth R. A. Hepatic and extrahepatic pathobiology of bacterial lipopoly-saccharides. Pharmacol. Rev. 45, 382, 1993. 

In addition to directly eliciting cell chemotaxis and free-radical production, PAF can also induce the release of various inflammatory cytokines, amongst which tumour necrosis factor (TNF) is of particular importance [ 312 ]. We have recently shown that PAF stimulates TNF production from peripheral blood derived monocytes and at picomolar concentrations amplifies lipopoly-saccharide (LPS)-induced TNF production, effects inhibited by various PAF antagonists [313]. PAF also acts synergistically with interferon-y (IFN-y) to increase the monocyte cytotoxicity. Furthermore, PAF can modulate the production of both interleukin 1 and interleukin 2 (IL-1, IL-2) from rat monocytes and lymphocytes, respectively [222, 223], cytokines which in turn elicit the release of other mediators and growth factors. 

Meyer A, Ptihler A, Niehaus K (2001) The lipopoly saccharides of the phytopathogenXanthomonas campestris pv. campestris induce an oxidative burst reaction in cell cultures of Nicotiana taba-cum. Planta 213 214-222... 

Zaidi, T. S., Fleiszig, S. M., Preston, M. J., Goldberg, J. B., and Pier, G. B. (1996). Lipopoly-saccharide outer core is a ligand for corneal cell binding and ingestion of Pseudomonas aeruginosa. Invest. Ophthalmol. Vis. Sci. 37, 976-986. 

Lowenstein CJ, Alley EW, Raval P, et al. Macrophage nitric-oxide synthase gene-2 upstream regions mediate induction by interferon-gamma and lipopoly-saccharide. Proc Natl Acad Sci USA 1993 90 9730-9734. 

Proteoglycan-derived carbohydrates, " Lipopoly saccharides, Glycoproteins, Food Polysaccharides ... 

Ui) Bacterial translocation from colon due to hypoxic damage Reperfusion damage to the colonocytes can impair the physical barrier between the contents of the colon and the blood. This leads to translocation of bacteria (some of which are pathogens (e.g. E. coli)), or lipopoly-saccharide (endotoxin) into the peritoneal cavity and evenmaUy into the bloodstream. Activation of the gut-associated immune system results in local inflammation which can also damage the barrier and hence increase bacterial translocation. This sets up a vicious circle, with the development of peritonitis and possible systemic sepsis (Figure 18.6). 

The reactions that take place in the complement system can be initiated in several ways. During the early phase of infection, lipopoly-saccharides and other structures on the surface of the pathogens trigger the alternative pathway (right). If antibodies against the pathogens become available later, the antigen-antibody complexes formed activate the classic pathway (left). Acute-phase proteins (see p. 276) are also able to start the complement cascade lectin pathway, not shown). 

This enzyme [EC 2.4.1.56] catalyzes the reaction of UDP-A-acetyl-D-glucosamine with a lipopolysaccharide to produce UDP and an A-acetyl-D-glucosaminyl-lipopoly-saccharide. Thus, this enzyme transfers A-acetylgluco-saminyl residues to a D-galactose residue in the partially completed lipopolysaccharide core. 

Heptoses and higher sugars may similarly be separated, and the identity of D-erythro-c-galacto-nonulose in avocado was determined by comparison of its gas-chromatographic behavior with that of a synthetic sample.336 Higher sugars have been separated, and identified, from avocado,151 Pichi,337 opium poppy,338 and bacterial lipopoly-saccharides.339... 

The occurrence of 3-deoxy-D-manno-octulosonic acid in lipopoly-saccharides has prompted its synthesis,537 together with the D-gal-octo158 and the D-gluco analogs.157 Although gas-liquid chromatography was successfully used to analyze the products of these syntheses, it has been reported that methanolysis of a bacterial endotoxin lipopolysaccharide failed to yield 3-deoxy-D-manno-octulosonic acid, presumably because of the lability of the latter to acid.381 However, Kasai and Nowotny have reported four peaks for the O-trimethylsilyl derivatives of 3-deoxy-D-manno-octulosonic acid obtained by methanolysis of the glycolipid from a Salmonella minnesota mutant.538 Reduced 3-deoxy-D-manno-octulosonic acid and its methyl ester have also been analyzed successfully as their acetates.339,539... 

Hydroquinone decreased interleukin (IL)-l secretion and protein and RNA synthesis of isolated human peripheral blood monocytes induced by Escherichia coli lipopoly-saccharide at micromolar concentrations (Carbonnelle etal., 1995). Hydroquinone (4 pmol/L) inhibited the growth of bone marrow cells from female C57BL/6 x DBA/2 mice (Seidel et al., 1991) and from male Swiss Webster and C57BL/6J mice (10 pmol/L) (Neun et al., 1992). Hydroquinone (50, 75 or 100 mg/kg bw, single intraperitoneal admi-... 

Three monosaccharides of the group were identified which contain an amino group at both C-2 and C-3. These include acylated 2,3-diamino-2,3-dideoxy-D-glucose, which is a component of the lipid A region of lipopoly-saccharides from Rhodopseudomonas,144 and 2,3-di(acetamido)-2,3-dideoxy-D-glucuronic145 and -D-mannuronic146 acids, identified as constituents of P. aeruginosa O-specific polysaccharides. The pathway of their biosynthesis, and their activated forms, remain unknown. 

The material presented in previous sub-sections clearly shows that both of the possible mechanisms of polysaccharide chain-assembly may operate in the biosynthesis of bacterial polysaccharides. There is no clearcut, mechanistic difference in the biosynthesis of O-specific chains of lipopoly-saccharides, exocellular polysaccharides, and carbohydrate chains of Grampositive, cell-wall polymers for every class of polymer, the existence of both mechanisms of chain assembly was demonstrated. 

Amide-linked fatty acids The fact that O-deacylation of lipopoly-saccharide with Na0CH3 C56°C) released (in addition to 12 0, 14 0 and 16 0) only 2 moles of the 4 moles of 3-OH-14 0 present in... 

Sterol carrier protein 2 has also been shown to be involved in the intracellular transport and metabolism of cholesterol. Hirai et al. (1994) suggested that sterol carrier protein 2 plays an important role during foam cell formation induced by acetylated LDL and may be an important step in atherosclerosis [142], Lipoproteins can bind lipopolysaccharide and decrease the lipopoly-saccharide-stimulated production of proinflammatory cytokines [142, 143], In addition, lipoprotein entrapment by the extracellular matrix can lead to the progressive oxidation of LDL because of the action of lipoxygenases, reactive oxygen species, peroxynitrite, or myeloperoxidase [144, 145],... 

IL-10 is considered one of the strongest inhibitors of neutrophil functions as well as the factor inhibiting the synthesis of IL-8 and IL-la initiated by lipopoly saccharide (LPS) (S6, S8). As in the case of IL-8, IL-10 is not detectable in the serum of healthy humans, and its concentration clearly increases in patients with AP (especially in the first 72 hr of the disease course). Significantly higher concentrations... 

Bhattacharjee AK, Izadjoo MI, Zollinger WD et al (2006) Comparison of protective efficacy of subcutaneous versus intranasal immunization of mice with a Brucella melitensis lipopoly-saccharide subunit vaccine. Infect Immun 74 5820-5825... 

Scheme 4.1 (a) Structure of the lipopoly saccharides of Gram-negative bacteria, (b) The structure of the lipid A from E. coli. (c) The structure of Kdo residue (a-3-deoxy-D-manno-oct-2-ulopyranosonic acid). For all structures, where not stated otherwise, sugars are a-D-pyranosides. Residues in bold are present as non-stoichiometric substitutions. Common abbreviations P, Phosphate, PPEtn, 2-aminoethanol diphosphate, PEtN, 2-aminoethanol phosphate, PCho, 2-trimethylaminoethanol phosphate Gly, glycine, Ac, Acetyl, Cm, Carbamoyl, Pyr, Pyruvic Acid... 

Kondakova, A.N., Vinogradov, E., Katzenellenbogen, E., Kocharova, N.A., Lindner, B., Knirel, Y.A. Structural studies on the lipopoly saccharide core of bacteria of the genus Citrobacter two different core structures in Citrobacter 014 serogroup. J Carbohydr Chem 28 (2009) 298-315. 

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