Lipopolysaccharide , lipid

Gram-negative (whole organisms peptidoglycans lipopolysaccharides [lipid A])... 

Daemen, T., Veninga, A., Dijkstra, J., and Scherphof, G. (1989) Differential effects of liposomeincorpo-ration on liver macrophage activating potencies of rough lipopolysaccharide, lipid A, and muramyl dipeptide Differences in susceptibility to lysosomal enzymes. Immunol. 142, 2469-2474. 

Keywords Pseudomonas aeruginosa Cystic fibrosis Lipopolysaccharide Lipid A Chronic infection Antibiotic resistance Innate immunity inflammation... 

Vedam, V., Haynes, J.G., Kannenberg, E.L., Carlson, R.W., Sherrier, D.J. A Rhizobium leguminosarum lipopolysaccharide lipid A mutant induces nitrogen-fixing nodules with delayed and defective bacteroid formation. Mol Plant-Microbe Interact 17 (2004) 283-291. 

Parker, J.H., Fredrickson, H.L., Vestal, J.R. White, D.C. (1982) Sensitive assay, based on hydroxy-fatty acids lipopolysaccharide lipid A for gram negative bacteria in sediments. Applied and Environmental Microbiology 44, 1170-7. 

Takayama, K., M. Olsen, P. Datta and R. L. Hunter, 1991, Adjuvant activity of nonionic block copolymers. V. Modulation of antibody isotype by lipopolysaccharides, lipid A and precursors. Vaccine 9 257-265. 

Mu rein Sacculus Globular Protein Lipopolysaccharide Lipid-Protein Complex... 

Some polymyxins are sold for second-line systemic therapy. Polymyxin B sulfate and colistimethate sodium can be used for intravenous, intramuscular, or intrathecal administration, especially for Pseudomonas aerupinosa mP QXiosis, but also for most other gram-negative organisms, such as those resistant to first-line antibiotics. Nephrotoxicity and various neurotoxicities are common in parenteral, but not in topical, use. Resistance to polymyxins develops slowly, involves mutation and, at least in some bacteria, adaptation, a poorly understood type of resistance that is rapidly lost on transfer to a medium free of polymyxin. Resistance can involve changes in the proteins, the lipopolysaccharides, and lipids of the outer membrane of the cell (52). Polymyxin and colistin show complete cross-resistance. 

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. 

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. 

Lipid Transfer Proteins Lipidation Lipopolysaccharide Lipoprotein Lipase... 

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. 

Using PTLC six major fractions of lipids (phospholipids, free sterols, free fatty acids, triacylglycerols, methyl esters, and sterol esters) were separated from the skin lipids of chicken to smdy the penetration responses of Schistosoma cercaria and Austrobilharzia variglandis [79a]. To determine the structure of nontoxic lipids in lipopolysaccharides of Salmonella typhimurium, monophosphoryl lipids were separated from these lipids using PTLC. The separated fractions were used in FAB-MS to determine [3-hydroxymyristic acid, lauric acid, and 3-hydroxymyristic acids [79b]. 

During ischaemia, NOS is activated by calcium influx or by cytokines like tumour necrosis factor (TNF) or by lipopolysaccharide (LPS) and NO is produced in excess. It has been proposed that the excitotoxic effect of glutamate, which contributes to ischaemia-induced neuronal damage, is mediated by increased production of NO via a chain of events that includes increases in intracellular calcium (via glutamate activation of NMDA receptors), calcium activation of NOS, production of NO and peroxynitrite, and induction of lipid peroxidation. In fact, N-nitro-L-atginine, a selective inhibitor of NOS, has been shown to prevent glutamate-induced neurotoxicity in cortical cell cultures (Dawson rf /., 1991). 

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]. 

A variety of lipid adjuvants and protein mediators have also been shown to influence the immune response to antigens encapsulated in liposomes. The most widely used examples of such adjuvants for practical immunization procedures are endotoxin (including lipid A and lipopolysaccharide) and numerous types of lipophilic derivatives of muramyl dipeptide. 

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. 

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