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

The lipopolysaccharide from Thiocapsa roseopersicina was isolated by phenol/water, being found in the water phase. It is cleaved into a polysaccharide moiety (degraded polysaccharide) and lipid A by hydrolysis with 10% acetic acid (100 degree C, 3 h). D-Mannose, L-rhamnose, 3-amino-3, 6-dideoxy-D-galactose and D-glucose are the major constituents of the degraded polysaccharide. 2-O-Methyl-L-rhamnose, 3-O-methyl-D-mannose, D-galactose, glucosamine and quinovosamine are minor constituents. D-Glycer-D-manno-heptose (tentatively identified) and 3-deoxy-D-manno-octulosonic acid were detected in only small amounts. Conspicuously, lipid A from T. roseopersicina contains a neutral sugar, D-mannose, in addition to D-glucosamine, as had been observed with lipid A from Chromatium vinosum D. Major fatty acids are beta-hydroxymyristic and lauric acids. Only trace amounts of phosphorus were found indicating this lipid A to be free of phosphate. The lipopolysaccharide of T. roseopersicina represents the O-antigen of the strain. It reacts with antisera prepared against living or heat-killed cells in passive hemagglutination.
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PMID:Isolation and characterization of the lipopolysaccharide of Thiocapsa roseopersicina. 71 Apr 28

The antiphagocytic antigen (antigen [a]) comprising the microcapsule of a strain of Campylobacter fetus subsp. intestinalis has been purified from culture supernatants by ammonium sulfate fractionation and free-flow electrophoresis. Antigen [a] is a glycoprotein containing about 4% carbohydrate consisting of hexose, pentose, and methylpentose. The composition of the protein was typical of bacterial extramural structural proteins in its low content of basic, aromatic, and sulfur-containing amino acids. The protein had a high content of aspartic acid, threonine, glycine, and alanine. Antigen [a] had an Rf of 0.33 on polyacrylamide gel electrophoresis and a molecular weight calculated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis of approximately 98,000. In contrast to its free form in culture supernatants, antigen [a] in vesicles derived from sheared cells appeared to exist in a complex with lipopolysaccharide. This complex could be dissociated by ethylenediaminetetraacetic acid or by ethylenediaminetetraacetic acid plus Triton X-100. A mutant strain that lacked a microcapsule, when incubated with soluble antigen [a] in a calcium medium, became agglutinable by monospecific [a] antiserum and showed an additional structural layer similar in appearance to the microcapsule on its cell wall. Points of similarity are emphasized between antigen [a] of C. fetus and the outer structural protein of the taxonomically related Spirillum serpens.
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PMID:Microcapsule of Campylobacter fetus: chemical and physical characterization. 73 Mar 87

During phagocytosis of opsonized lipopolysaccharide-coated paraffin oil droplets, rabbit alveolar macrophages reduced nitroblue tetrazolium, which effect was in part inhibitable with the use of superoxide dismutase. Exposure of cytochalasin-B-treated rabbit alveolar macrophages to opsonized zymosan led to the generation of superoxide, as quantitated by ferricytochrome C reduction. It was found that nitroblue tetrazolium in the presence of ferricytochrome C could in turn serve as scavenger of superoxide during stimulation of cytochalasin-B-treated rabbit alveolar macrophages. Following challenge with either opsonized zymosan or the membrane perturbant digitonin, rabbit alveolar macrophages released hydrogen peroxide into the extracellular medium. Employment of the surface membrane stimulant phorbol myristrate acetate led to activation of the hexose monophosphate shunt, which activity could be further enhanced in the presence of superoxide dismutase or attenuated in the presence of catalase. These studies demonstrate that rabbit alveolar macrophages release superoxide and hydrogen peroxide during surface membrane perturbation. In turn, hydrogen peroxide generation can stimulate the hexose monophosphate shunt.
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PMID:Oxidative metabolic responses of rabbit pulmonary alveolar macrophages. 76 Aug 63

Exopolysaccharides were prepared from cultures of four Myxococcus strains grown on solid and in liquid media, and also from the fruiting bodies. Lipopolysaccharides could be extracted with aqueous phenol from the vegetative bacteria, but were absent from microcysts. Mannose and D-glucose were present in all the exopolysaccharides and three of the lipopolysaccharides examined. Other monosaccharides identified in the exopolysaccharides were D-galactose, N-acetylglucosamine and N-acetylgalactosamine. The composition of the lipopolysaccharides was more complex than that of the exopolysaccharides and, in addition to the neutral hexoses and amino sugars, rhamnose was identified in two preparations and ribose in another. No lipopolysaccharide preparations contained O-methyl xylose or heptose. The polysaccharides secreted by the bacillary forms grown on solid or in liquid media closely resembled the polysaccharides isolated from the fruiting bodies, in which they provided a matrix surrounding the microcysts. Each pair of polysaccharides contained the same monosaccharides, although in slightly different proportions. Differences were found in preparations from different strains. These results suggest that in the development cycle of the genus Myxococcus, considerable use is made of pre-existing enzyme systems to synthesize the precursors necessary for polysaccharide synthesis. Any specific difference between the polysaccharide produced by the bacilli and that surrounding the microcysts may lie in the fine structure, rather than in the individual components.
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PMID:Comparison of polysaccharides produced by Myxococcus strains. 80 82

To investigate the possibility that human polymorphonuclear leukocytes (PMN) elaborate sufficient amounts of hydrogen peroxide (H2O2) and other radicals of reduced oxygen to be autotoxic and retard directed cell movement and phagocytosis, the rate of ingestion of opsonized lipopolysaccharide-paraffin oil particles and movement through Nuclepore filters were studied. Ingestion rates were increased under anaerobic conditions and in normal aerobic conditions in the presence of extracellular catalase but not superoxide dismutase (SOD) or scavengers of singlet oxygen or hydroxyl radicals. Conversely, ingestion rates were decreased when cells were exposed to H2O2 or a superoxide anion (O2-)-H2O2 generating system of xanthine-xanthine oxidase. Catalase, but not SOD, prevented the effect and also enhanced the directed movement of PMN in normal aerobic conditions. PMN from volunteers administered 1600 U/day of the membrane lipid antioxidant alpha-tocopherol were hyperphagocytic but killed Staphylococcus aureus 502A less effectively than controls, suggesting that less H2O2 was available to damage PMN or kill bacteria. H2O2-dependent stimulation of the hexose monophosphate shunt, H2O2 release from phaogytizing PMN, and fluoresceinated concanavalin A cap formation promoted by H2O2 damage to microtubules were all diminished, but the release of O2- from phagocytizing PMN was not diminished in the vitamin E group. These results support the hypothesis that directed movement and phagocytosis by PMN are attenuated by autooxidative damage to the cell membrane by endogenously derived H2O2 and that the administration in vivo of vitamin E may prevent this damage by scavenging H2O2.
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PMID:Autooxidation as a basis for altered function by polymorphonuclear leukocytes. 87 28

The lipopolysaccharide of Escherichia coli BB and a number of R-phage selected (e.g. T3, T4) cell-wall-defective mutants were analyzed. From their lipopolysaccharides the respective core oligosaccharides were obtained. Following dephosphorylation, the oligosaccharides were methylated and analyzed by gas chromatography/mass spectrometry. This revealed the sugar sequence in the hexose-heptose region of the core. The linkage of heptose (Hep) to 2-keto-3-deoxyoctonate (KDO) was established as ... Hep 1,5 leads to KDO ... by methylation analysis. The substituted derivative of KDO was identified by gas chromatography and mass spectrometry. The KDO region contains three KDO units. Its structure was elaborated by (a) selective removal and identification of 7-phosphoryl ethanolamine-KDO (KDO-PN), (b) periodate oxidation and thiobarbituric acid reaction in conjunction with mild hydrolysis, (c) a modified methylation analysis. Phosphate substitution of E. coli BB core was studied by beta-elimination and using the information obtained with KDO-PN. The structures of the cell wall lipopolysaccharides from E. coli BB and cell-wall-defective mutants are given.
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PMID:Cell-wall lipopolysaccharide from Escherichia coli B. 110 Mar 90

The structure of the O-polysaccharide component of the lipopolysaccharide produced by Escherichia coli 0119 was determined by the use of methylation analysis, periodate oxidation, 1D and 2D nuclear magnetic resonance spectroscopy, and mass spectrometric methods. The O-polysaccharide was found to be a high molecular weight polymer of a repeating pentasaccharide unit composed of D-mannose, D-galactose, L-rhamnose, 2-acetamido-2-deoxy-D-glucose, and 2-acetamido-2,3-dideoxy-3-formamido-D-rhamnose residues (1:1:1:1:1) and had the structure: [formula: see text]
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PMID:Structure of the O-antigen of Escherichia coli 0119 lipopolysaccharide. 128 12

A transposon Tn5-induced mutant of Rhizobium meliloti Rm2011, designated Rm6963, showed a rough colony morphology on rich and minimal media and an altered lipopolysaccharide (LPS). Major differences from the wild-type LPS were observed in (i) hexose and 2-keto-3-deoxyoctonate elution profiles of crude phenol extracts chromatographed in Sepharose CL-4B, (ii) silver-stained sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis patterns of crude and purified LPS fractions, and (iii) immunoreactivities otherwise present in purified LPS of the parental strain Rm2011. In addition, Rm6963 lost the ability to grow in Luria-Bertani medium containing the hydrophobic compounds sodium deoxycholate or SDS and showed a decrease in survival in TY medium supplemented with high calcium concentrations. The mutant also had altered symbiotic properties. Rm6963 formed nodules that fixed nitrogen but showed a delayed or even reduced ability to nodulate the primary root of alfalfa without showing changes in the position of nodule distribution profiles along the roots. Furthermore, 2 to 3 weeks after inoculation, plants nodulated by Rm6963 were smaller than control plants inoculated with wild-type bacteria in correlation with a transient decrease in nitrogen fixation. In most experiments, the plants recovered later by expressing a full nitrogen-fixing phenotype and developing an abnormally high number of small nodules in lateral roots after 1 month. Rm6963 was also deficient in the ability to compete for nodulation. In coinoculation experiments with equal bacterial numbers of both mutant and wild-type rhizobia, only the parent was recovered from the uppermost root nodules. A strain ratio of approximately 100 to 1 favoring the mutant was necessary to obtain an equal ratio (1:1) of nodule occupancy. These results show that alterations in Rm6963 which include LPS changes lead to an altered symbiotic phenotype during the association with alfalfa that affects the timing of nodule emergence, the progress of nitrogen fixation, and the strain competitiveness for nodulation.
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PMID:A Rhizobium meliloti lipopolysaccharide mutant altered in competitiveness for nodulation of alfalfa. 132 69

Deletions which removed rfa genes involved in lipopolysaccharide (LPS) core synthesis were constructed in vitro and inserted into the chromosome by linear transformation. The deletion delta rfa1, which removed rfaGPBI, resulted in a truncated LPS core containing two heptose residues but no hexose and a deep rought phenotype including decreased expression of major outer membrane proteins, hypersensitivity to novobiocin, and resistance to phage U3. In addition, delta rfa1 resulted in the loss of flagella and pili and a mucoid colony morphology. Measurement of the synthesis of beta-galactosidase from a cps-lacZ fusion showed that the mucoid phenotype was due to rcsC-dependent induction of colanic acid capsular polysaccharide synthesis. Complementation of delta rfa1 with rfaG+ DNA fragments resulted in a larger core and restored the synthesis of flagella and pili but did not reverse the deep rough phenotype or the induction of cps-lacZ, while complementation with a fragment carrying only rfaP+ reversed the deep rough phenotype but not the loss of flagella and pili. A longer deletion which removed rfaQGPBIJ was also constructed, and complementation studies with this deletion showed that the product of rfaQ was not required for the functions of rfaG and rfaP. Thus, the function of rfaQ remains unknown. Tandem mass spectrometric analysis of LPS core oligosaccharides from complemented delta rfa1 strains indicated that rfaP+ was necessary for the addition of either phosphoryl (P) or pyrophosphorylethanolamine (PPEA) substituents to the heptose I residue, as well as for the partial branch substitution of heptose II by heptose III. The substitution of heptose II is independent of the type of P substituent present on heptose I, and this results in four different core structures. A model is presented which relates the deep rough phenotype to the loss of heptose-linked P and PPEA.
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PMID:Role of the rfaG and rfaP genes in determining the lipopolysaccharide core structure and cell surface properties of Escherichia coli K-12. 134 43

O-Specific polysaccharide composed of L-rhamnose and 2-acetamido-2-deoxy-D-mannose was obtained on mild acid degradation of the V. fluvialis lipopolysaccharide. On the basis of the 13C-NMR data and methylation studies, the following structure was suggested for the polysaccharide repeating unit: ----4)-alpha-L-Rhap-(1----3)-beta-D-ManpNAc-(1---- This structure was confirmed by calculations using known glycosidation effects on 13C chemical shifts.
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PMID:[Structure of the O-specific polysaccharide of Vibrio fluvialis serovar 3]. 138 22


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