Lipopolysaccharides components

Hollingsworth, R.I., Lill-Elghanian, D.A. Isolation and characterization of the unusual lipopolysaccharide component, 2-amino-2-deoxy-2-JV-(27-hydroxyoctacosanoyl)-3-0-(3-hydroxy-tetradecanoyl)-gluco-hexuronic acid, and its de-O-acylation product from the free lipid A of Rhizobium trifolii ANU843. J Biol Chem 264 (1989) 14039-14042. 

Pyrogenic contamination is detected using two tests. In the older method, rabbits are injected with product samples, and rectal temperature is measured. Compendial limits are established with respect to how much temperature increase is permitted before the product is judged to be free or contaminated with pyrogens. The newer method involves a relatively simple in vitro technique called the Limulus Amebocyte Lysate (LAL) test. It is based on the high senstivity of amebocytes of the horseshoe crab (Limulus) to the lipopolysaccharide component of endotoxins originating from Gramnegative bacteria. The LAL test is now the USP method of choice with endotoxin limits established for most SVIs. ... 

Salmonella typhimurium - This organism s O antigen is the major lipopolysaccharide component of the outer membrane. Lipopoly saccharides contain repeating oligosaccharide units attached to a basal core... 

Lipopolysaccharide (LPS) endotoxins are characteristic Gram-negative outer-cell components which are produced by many cyanobacteria. Although LPS have been characterized and found to be toxic to laboratory animals after isolation from cyanobacteria, their toxicity to rodents is less potent than the endotoxins of enteric pathogens such as Salmonella Typical symptoms of animals suffering from LPS intoxication include vomiting, diarrhoea, weakness and death after hours rather than minutes. 

FIGURE 8.18 Dolichol phosphate is an initiation point for the synthesis of carbohydrate polymers in animals. The analogous alcohol in bacterial systems, undecaprenol, also known as bactoprenol, consists of 11 isoprene units. Undecaprenyl phosphate delivers sugars from the cytoplasm for the synthesis of cell wall components such as peptidoglycans, lipopolysaccharides, and glycoproteins. Polyprenyl compounds also serve as the side chains of vitamin K, the ubiquinones, plastoquinones, and tocopherols (such as vitamin E). 

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. 

In Gram-negative bacteria the cell wall is only about 3 nm thick, and located in the extended periplasmatic space between the inner membrane (IM) and an additional outer membrane (OM). The lipid monolayer in the outer leaflet of the OM contains about 90% lipopolysaccharides (LPS). LPS consist of Lipid A and an oligosaccharide component, which is highly specific for individual bacterial species and phenotypes [108, 114]. 

Diagnosis of gonococcal infections can be made by gram-stained smears, culture (the most reliable method), or newer methods based on the detection of cellular components of the gonococcus (e.g., enzymes, antigens, DNA, or lipopolysaccharide) in clinical specimens. 

C. Galanos, O. Luderitz, E. Th. Rietschel, and O. Westphal in T. W. Goodwin. (Ed.), International Review of Biochemistry, Vol. 14, Biochemistry of Lipids II Newer Aspects of the Chemistry and Biology of Bacterial Lipopolysaccharides, with Special Reference to Their Lipid A Component, p. 239. University Park Press, Baltimore, 1977. 

B. Lindner, U. Zahringer, E. Th. Rietschel, and U. Seydel, in A. Fox, S. L. Morgan, L. Larsson, and G. Odham (Eds.), Analytical Microbiology Methods Structural Elucidation of Lipopolysaccharides and Their Lipid A Component Application of Soft Ionization Mass Spectrometry, p. 149. Plenum, New York/London, 1990. 

Some examples of transformations involving carbonyl ylides are listed in Table 4.20. Entry 1 illustrates the conversion of P-acyloxy-a-diazoesters into a-acyloxyacrylates by ring fission of a cyclic carbonyl ylide [978]. This reaction has been used for the synthesis of the natural aldonic acid KDO (3-deoxy-Z)-manno-2-octulosonic acid), which is an essential component of the cell wall lipopolysaccharide of gram-negative bacteria (Figure 4.15). 

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