Polysaccharides lipopolysaccharides

Myeloma proteins occur in animal tumors of various types. The synthesis of these proteins can be induced in some experimental animals by injection of mineral oil, or the implantation of plastic discs.161 Myeloma proteins were shown to possess antibody activity, with specificity for different types of substances.161 Some of these proteins were found to combine with such carbohydrates as bacterial, cell-wall polysaccharides, lipopolysaccharides, dextrans, levans, and galactans.162 Myeloma proteins that combine with galactans or dextrans possess anti-galactan activity,163,164 or anti-dextran activity,165-167 and have been studied most extensively. 

The field is actually in a good position to contribute to the development of bacterial polysaccharide glycoconjugate vaccines. Numerous fragments of capsular polysaccharides, lipopolysaccharides, or other bacterial carbohydrates have been synthesized and their protein conjugates obtained [87]. 

Alkyl halide, sodium hydride in DMSO 2.5.1 General, substances insoluble in common organic solvents, polysaccharides, lipopolysaccharides, peptides, sterically hindered functions, amides, amino acids Esters, and as stated for procedure 2.4 peptides containing sulfur-amino acids, histidine and arginine 132] O-Acyl groups are replaced with O-alkyl groups. For N-isopropyl amino acids, isopropyl ester formation, (see Chapter 2)... 

Properties.— The properties of glycoside hydrolases have been reviewed. As part of a series on surface carbohydrates of the prokaryotic cell, a comprehensive chapter deals with enzymes acting on bacterial surface carbohydrates. Enzymes hydrolysing capsular and slime polysaccharides, lipopolysaccharides, and teichoic acids are treated in detail. 

In summary, all bacterial cell walls appear to contain short peptides of variable sequence, which cross-link amino-sugar glycan chains to form macromolecular networks important for the integrity of the bacterial cells. Linked to the networks (covalently or otherwise) are a variety of structures including proteins, polysaccharides, lipopolysaccharides, teichoic... 

Cell wall Peptidoglycan a rigid framework of polysaccharide cross-linked by short peptide chains. Some bacteria possess a lipopolysaccharide- and protein-rich outer membrane. Mechanical support, shape, and protection against swelling in hypotonic media. The cell wall is a porous nonselective barrier that allows most small molecules to pass. 

As shown in Figure 9.24, the outer membrane of Gram-negative bacteria is coated with a highly complex lipopolysaccharide, which consists of a lipid group (anchored in the outer membrane) joined to a polysaccharide made up of long chains with many different and characteristic repeating structures... 

FIGURE 9,24 Lipopolysaccharide (LPS) coats the outer membrane of Gram-uegative > bacteria. The lipid portion of the LPS is embedded iu the outer membrane and is linked to a complex polysaccharide. 

Many different types of carbohydrate-containing molecules are located on the surface of microbial cells. Some of these are components of die microbial cell wall and are limited to certain types of micro-organisms such as bacterial peptidoglycan, lipopolysaccharides, techoic adds and yeast mannans. Other polysaccharides are not... 

A lipopolysaccharide (LPS) is any compound consisting of covalently linked lipids and polysaccharides. The term is used more frequently to denote a cell wall component from Gram-negative bacteria. LPS has endotoxin activities and is a polyclonal stimulator of B-lymphocytes. 

Shortly afterwards, Westphal, Liideritz, and their coworkers using the newly developed method of paper chromatography, found a new class of sugars in lipopolysaccharides (LPS) from Gram-negative bacteria, and identified them as 3,6-dideoxyhexoses. This work is summarized in Ref. 4. These discoveries initiated more-systematic investigations of hydrolyzates from bacterial polysaccharides, and a number of new monosaccharides were completely or partially identified. This development has been summarized by Ashwell and Hickman. ... 

Abbreviations LPS, lipopolysaccharide EPS, extracellular polysaccharide Photosynth., photosynthetic prokaryote. 

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. 

Following with bacterial infections and anti-adhesion strategies,86 88 NMR based structural studies have been conducted on O-polysaccharide chains in these past few years,38 40,42,43 in order to elucidate the molecular basis and the role of the lipopolysaccharides in these pathologies. 

Figure 2.8. Proposed mechanism of action of BPI (a) The external polysaccharide chain of lipopolysaccharide (LPS) is a hydrophilic barrier stabilised by Ca2+ and Mg2+, which cross-link the LPS chains, (b, facing) BPI is highly basic and initially interacts by displacing the cations that bind to charged sites on the surface. See text for details.

The observed adjuvanticity of Bordetella pertussis is largely attributable to the presence of pertussis toxin and lipopolysaccharide (LPS). LPS, a constituent of the cell envelope of Gramnegative bacteria (Chapter 3), essentially consists of polysaccharide moieties to which lipid (lipid A) is covalently attached. 

N. catarrhalis,560 N. perflava,559 Moraxella duplex and Micrococcus calco-aceticus,443 and Escherichia coli,420 Vicari and Kabat,45 in studies of blood-group oligosaccharides, and Hellerqvist and colleagues,53 in an examination of the common core-polysaccharide of Salmonella typhimurium, have used similar methods. The examination of amino sugars as their peracetylated aminodeoxyalditols has also been used by Liideritz and colleagues72 to establish the occurrence of 4-amino-4-deoxy-L-arabinose in Salmonella lipopolysaccharides, and has been extended to aminodeoxyheptoses by Williams and Perry.561... 

One of the most impressive findings has been the discovery of lipid intermediates in the biosynthesis of polysaccharides (see Refs. 2 and 465.) At least two structurally different types of these compounds exist the intermediate may be an isoprenoid alcohol ester of the glycosyl pyrophosphate or the analogous derivative of the glycosyl phosphate. Derivatives of the first type are formed by reaction between the sugar nucleotide and the alcohol phosphate, for example, undecaprenyl phosphate (120), which participates in the biosynthesis of Salmonella lipopolysaccharide.466... 

W. Jachymek, J. Czaja, T. Niedziela, C. Lugowski and L. Kenne, Structural studies of the -specific polysaccharide of Hafnia alvei strain PCM 1207 lipopolysaccharide, Eur. J. Biochem., 1999, 266, 53-61. 

The polysaccharide component of a lipopolysaccharide can be separated from the lipid component by selective hydrolysis of the glyco-sidic linkages of the 3-deoxy-D-manno-octulosonic acid residues connecting these two components. The conditions for the hydrolysis are mild, namely, 0.1 M acetic acid for 1.5 h at 100° (Ref. 18). Similar conditions, namely, M formic acid for 1 h at 100° or 0.05 M hydrogen chloride in methanol for 1 h at 85°, were used to split off the sialic acid residues from gangliosides.19,20... 

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