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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A method is described for the preparation of outer and cytoplasmic membranes of Pseudomonas aeruginosa, and the outer membrane proteins characterized. Isolated outer and cytoplasmic membranes differed markedly in the content of 2-keto-3-deoxyoctonate (lipopolysaccharide) and phospholipid as well as in the localization of certain enzymes (NADH oxidase, succinate dehydrogenase, D-lactate dehydrogenase, malate dehydrogenase, and phospholipase), and also in the microscopic morphology. The outer membrane preparation showed activity neutralizing a certain bacteriocin or bacteriophages, whereas the cytoplasmic membrane preparation showed no neutralizing activity. The protein composition of membrane preparations from five different strains of P. aeruginosa [P14, M92 (PAO1), PAC1, P15, and M2008 (PAT)] were determined by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. More than 50 protein bands were detected in the cytoplasmic membrane preparation. The protein compositions of outer membranes from the five different strains were very similar: at least 6 major bands were found (apparent molecular weights: Band D, 50,000; band E, 45,000; band F, 33,000; bands G and H, 21,000; and band I, 8,000). The protein composition of outer membranes was affected by some physiological growth conditions. Some features of major outer membrane proteins were also studied. Band F showed anomalous migration on SDS polyacrylamide gel electrophoresis depending on the solubilizing conditions or pretreatment with TCA. Band I seemed to be a protein analogous to the lipoprotein which had been found in the outer membrane of Escherichia coli.
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PMID:Separation and characterization of the outer membrane of Pseudomonas aeruginosa. 9 43

A simple preparative method is described for isolation of the cytoplasmic and outer membranes from E. coli. The characteristics of both membrane fractions were studied chemically, biologically, and morphologically. Spheroplasts of E. coli K-12 strain W3092, prepared by treating cells with EDTA-lysozyme [EC 3.2.1.17], were disrupted in a French press. The crude membrane fraction was washed with 3 mM EDTA-10% (w/v) sucrose, pH 7.2, and the cytoplasmic membranes and outer membranes were separated by sucrose isopycnic density gradient centrifugation. The crude membrane fraction contained approximately 10% of the protein of the whole cells, 0.3% of the DNA, 0.7% of the RNA, 0.3% of the peptidoglycan, and about 30% of the lipopolysaccharide. The cytoplasmic membrane fraction was rich in phospholipid, while the outer membrane fraction contained much lipopolysaccharide and carbohydrate; the relative contents of lipopolysaccharide and carbohydrate per mg protein in the cytoplasmic membrane fraction were 12 and 40%, respectively, of the contents in the outer membrane fraction. Cytochrome b1, NADH oxidase, D-lactate dehydrogenase [EC 1.1.1.28], succinate dehydrogenase [EC 1.3.99.1], ATPase [EC 3.5.1.3], and activity for concentrative uptake of proline were found to be localized mainly in the cytoplasmic membranes; their specific activities in the outer membrane fraction were 1.5 to 3% of those in the cytoplasmic membrane fraction. In contrast, a phospholipase A appeared to be localized mainly in the outer membranes and its specific activity in the cytoplasmic membrane fraction was only 5% of that in the outer membrane fraction. The cytoplasmic and outer membrane fractions both appeared homogeneous in size and shape and show vesicular structures by electron microscopy. The advantages of this method for large scale preparation of the cytoplasmic and outer membrane fractions are discussed.
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PMID:Cytoplasmic membrane vesicles of Escherichia coli. A simple method for preparing the cytoplasmic and outer membranes. 12 74

Membrane vesicles isolated from Escherichia coli ML 308--225 have been analyzed by crossed immunoelectrophoresis, and immunoprecipitates corresponding to the following cellular components have been identified: ATPase (EC 3.6.1,3), two or three NADH dehydrogenases (EC 1.6.99.3), D-lactate dehydrogenase (EC 1.1.1.27), glutamate dehydrogenase (EC 1.4.1.4), dihydro-orotate dehydrogenase (EC 1.3.3.1), 6-phosphogluconate dehydrogenase (EC 1.1.1.43), polynucleotide phosphorylase (EC 2.3.7.8), beta-galactosidase (EC 3.2.1.23), lipopolysaccharide, and Braun's lipoprotein. The cellular origin of many of the vesicle immunogens is determined, and Braun's lipoprotein is used as a marker to quantitate the extent of outer membrane contamination (less than 3%). Membrane antigens are also characterized with regard to their amphiphilic or hydrophilic properties by charge-shift crossed immunoelectrophoresis. Furthermore, the following immunogens cross-react with components in membrane vesicles prepared from Salmonella typhimurium: one of the three NADH dehydrogenases, ATPase, polynucleotide phosphorylase, 6-phosphogluconate dehydrogenase, Braun's lipoprotein, and three unidentified antigens. In the accompanying paper [Owen, P., & Kaback, H. R. (1979) Biochemistry 18 (following paper in this issue)] quantitative immunoadsorption is utilized to establish the topology of the vesicles with respect to the distribution of antigens on the inner and outer faces of the membrane.
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PMID:Immunochemical analysis of membrane vesicles from Escherichia coli. 21 20

1. The crude envelope preparation obtained by sonication of Proteus mirabilis cells in the presence of lysozyme was separated into outer and cytoplasmic membrane fractions by sucrose density gradient centrifugation. The outer membrane fraction accounted for about two thirds of the dry weight of the envelope preparation. 2. In thin sections, the outer and cytoplasmic membrane fractions were shown to consist of vesicles bounded by a single trilaminar membrane, but those of the outer membrane were considerably smaller and were frequently open, forming C-shaped structures. The cytoplasmic membrane vesicles were cleaved by freeze fracturing to expose fracture faces studded with particles, while the outer membrane fragments resisted cleavage. 3. The outer membrane fraction consisted of protein (similar to 40%), lipopolysaccharide (similar to 36%) and lipid (similar to 18%) and had a density of about 1.22 g/cm3. The cytoplasmic membrane fraction consisted mostly of protein (similar to 56%) and lipid (similar to 38%), had a density of about 1.16 g/cm3, and contained almost all the NADH oxidase, succinate and D-lactate dehydrogenase activities of the crude envelope preparation. 4. Electrophoresis in polyacrylamide gels containing sodium dodecylsulfate revealed over 20 polypeptide bands in the cytoplasmic membrane fraction and only 6-7 in the outer membrane fraction. The outer membrane electrophorogram was dominated by a major band (mol. wt 40 000) which was resolved into two bands when electrophoresed in an acidic gel system. Amino acid analysis revealed a higher content of polar amino acids in the protein moiety of the outer membrane.
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PMID:The outer membrane of Proteus mirabilis. I. Isolation and characterization of the outer and cytoplasmic membrane fractions. 109 Dec 89

Taurolidine (Geistlich Pharm, AG, Wolhusen, Switzerland), a derivative of the amino acid taurine, is commonly used in some parts of the world as an adjunctive therapy for various infections. Its mechanism of action is thought to be related to its antimicrobial properties, including its ability to interfere with some of the biological activities of endotoxin (lipopolysaccharide, LPS). For example, taurolidine has been shown to protect animals against endotoxic shock and death. In this study we examined the ability of taurolidine to block LPS-induced tumor necrosis factor (TNF) and interleukin 1 (IL-1) synthesis in human peripheral blood mononuclear cells (PBMC) from 27 donors. We observed a dose-dependent reduction in the synthesis of these two cytokines when taurolidine was preincubated with LPS before being added to PBMC. This reduction was independent of the molar ratio of taurolidine to LPS but was related to the concentration of taurolidine present in the PBMC cultures. There was a 80 to 90% reduction in total IL-1 and TNF synthesis induced by LPS at concentrations of taurolidine of 40 to 100 micrograms/mL; the vehicle was without effect. Following a 30-min preincubation with PBMC, taurolidine could be washed from the cells and still suppress cytokine synthesis induced by LPS. Using release of lactic acid dehydrogenase, 100 micrograms/mL of taurolidine was not toxic for PBMC. Taurolidine also reduced IL-1 and TNF synthesis induced by the Staphylococcus aureus-derived toxic shock syndrome toxin-1 as well as that induced by nontoxic heat-killed Staphylococcus epidermidis organisms.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Taurolidine, an analogue of the amino acid taurine, suppresses interleukin 1 and tumor necrosis factor synthesis in human peripheral blood mononuclear cells. 179 Mar 4

Isolated membranes of the cell wall-less stable protoplast L-form of Proteus mirabilis were characterized by density gradient centrifugation and by assay for their major chemical constituents, proteins, phospholipids and lipopolysacchartide, and for some specific marker enzymes of the cytoplasmic membrane. In most of the analyzed properties the L-form protoplast membrane resembled the bacterial cytoplasmic membrane, with some notable modifications. Considerable amounts of lipopolysaccharide, normally an exclusive constituent of the outer membrane, were found. Furthermore, the L-form membranes contained the functions of the reduced nicotinamide adenine dinucleotide oxidase system, of D-lactate dehydrogenase (EC 1.1.1.28) and of succinate dehydrogenase (EC 1.3.99.1) at specific activities comparable to, or in some cases considerably higher than, those present in cytoplasmic membranes of the bacterial form. Of two peptidoglycan DD-carboxypeptidase/transpeptidases (EC 3.4.17.8 and EC 2.3.2.10). which are normally present in the cytoplasmic membrane of the bacterial form of P. mirabilis, the membrane of the protoplast L-form contained only one. Electron microscopy of thin sectioned L-form protoplasts showed extensive heterogeneity of membraneous structures. In addition to the single membraneous integument, internal membrane-bounded vesicles and multiple stacks of membranes were present, as the result of unbalanced growth and membrane synthesis in the L-form state.
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PMID:Membranes of the protoplast L-form of Proteus mirabilis. 700 76

Cell envelope fractions of Moraxella nonliquefaciens were isolated by a slight modification of Osborn's method. Two main membrane fractions were characterized chemically and morphologically. The density of the fraction containing cytoplasmic membrane material was 1.17 to 1.18 g cm-3 compared with 1.24 to 1.27 g cm-3 for the outer membrane fraction. Lipopolysaccharide was detected almost exclusively in the outer membrane fraction and sodium dodecyl sulphate polyacrylamide gel electrophoresis of this fraction revealed one dominant protein band with an apparent molecular weight of 45 000. Cross-contamination of the fractions was estimated to be about 10%, as calculated on the basis of the lipopolysaccharide fatty acid 3-hydroxydodecanoic acid and on the relative activities of D-lactate dehydrogenase and succinate dehydrogenase.
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PMID:Isolation of a relatively pure outer membrane fraction of Moraxella nonliquefaciens and a comparison of its characteristics with the cytoplasmic membrane-containing material. 736 51