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

Cell-free hemoglobin (Hb) is a purified preparation of human hemoglobin that is being developed as a resuscitation fluid. In vivo administration of hemoglobin has resulted in significant toxicity, due in part to contamination with bacterial endotoxin (lipopolysaccharide (LPS)). To better understand this toxicity, we have studied the interaction between Hb and LPS. Mixtures of each of three different Hb preparations (cross-linked alpha alpha Hb, cross-linked carbon monoxy-alpha alpha HbCO, and non-cross-linked (native) HbAo) and LPS (Escherichia coli O26:B6 or Proteus mirabilis S1959) were examined by several independent methods for evidence of Hb.LPS complex formation. Binding assays in microtiter plates demonstrated saturable binding of LPS to immobilized Hb, with a kD of 3.1 x 10(-8) M. Binding of LPS to Hb also was demonstrated wiht a radiolabeled LPS photoaffinity probe. Ultrafiltration of Hb/LPS mixtures by 300- and 100-kDa cut-off membranes showed that the majority of LPS in these mixtures (87-97 and 64-72%, respectively) was detected in the filtrates, in contrast to the lack of filterability of LPS in the absence of Hb. Density centrifugation demonstrated that LPS co-migrated with each of the three Hbs, whereas unbound LPS had a distinctly greater sedimentation velocity than Hb or Hb.LPS complexes. Nondenaturing polyacrylamide gel electrophoresis demonstrated that in the presence of Hb, LPS migrated into the gel and co-electrophoresed with Hb, whereas LPS alone did not appreciably enter the gel. Finally, precipitation by ethanol of each of the three Hb preparations was increased in the presence of LPS compared with precipitation in the absence of LPS. Interaction of LPS with each of the three Hb preparations was also associated with altered biological activity of LPS, as shown by enhancement of LPS activation of Limulus amebocyte lysate. Therefore, our data provide several lines of independent evidence for Hb-LPS complex formation and indicated that LPS exhibited altered physical characteristics and enhanced biological activity in the presence of Hb.
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PMID:Hemoglobin, a newly recognized lipopolysaccharide (LPS)-binding protein that enhances LPS biological activity. 792 95

An exocellular polysaccharide produced by a clinical isolate of Proteus vulgaris (ATCC 49990) was shown by composition, methylation, periodate oxidation, and nuclear magnetic resonance analyses to be composed of repeating trisaccharide units containing D-galactose, 2-acetamido-2-deoxy-D-glucose and pyruvic acid (2:1:1), and having the structure: [formula: see text] The homologus smooth lipopolysaccharide of the P. vulgaris strain was determined to have an O-polysaccharide component having the same structure as the above extracellular polysaccharide.
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PMID:The structure of the polysaccharide produced by Proteus vulgaris (ATCC 49990). 815 52

The second collection of the novel species Proteus penneri consists of 25 strains from which only two have shown rough from properties in the tests differentiating S and R variants of bacteria. The migration pattern of their lipopolysaccharides in gel electrophoresis was leader-like, typical for smooth organisms. 13 out of 25 lipopolysaccharide preparations showed strong-reactivity with anti-0 sera in semi-quantitative precipitation test. Serological similarity between the strains within species Proteus penneri is discussed.
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PMID:[Selected properties of strains of a new species of Proteus penneri from the second American collection]. 823 47

O-specific polysaccharide was obtained on mild acid degradation of Proteus penneri strain 14 lipopolysaccharide and found to contain equimolar of D-galactose, D-ribose, 2-acetamido-2-deoxy-D-glucose, N-(D-galacturonoyl)-L-alanine and 3-(Nacety-L-alanyl)-amido-3,6-dideoxy-D-glucose. On the basis of non-destructive NMR analysis it was concluded that repeat unit of the 0-specific polysaccharide of P. penneri 14 has the following structure: -2-beta-D- Quip3NAlaAc-(1-->4)-alfa-D-GalpAAla-(1-->2)-beta-D- Ribf-(1-->4)-beta-D-Galp-(1-->3)-beta-D--GlcpNAc-(1--> This structure was confirmed by structural elucidation of trisaccharide and disaccharide fragments prepared on mild acid hydrolysis of the polysaccharide. Immunodominant role of the partial structures of the pentasaccharide repeating unit in manifesting serological specificity of P. penneri 14 was discussed. Very weak cross-reactions of P. penneri anti-serum were observed with E. coli 0114 and Shigella boydii 08 LPS's, which showed some structural similarities. No cross-reaction with P. mirabilis 027 LPs was detected.
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PMID:[Immunochemical studies of O-specific polysaccharide from Proteus penneri 14 lipopolysaccharide]. 823 51

O-specific polysaccharide was obtained an mild acid degradation of Proteus penneri strain 42 lipopolysaccharide and found to contain D-glucose, D-galacturonic acid and 2-acetamido-2-deoxy-D-glucose in molar ratio 2:1:1. Methylation analysis showed that the polysaccharide is linear, one of the glucose residue is substituted at position 2, the second one and the residue of galacturonic acid at position 4, and the 2-acetamido-2-deoxy-D-glucose residue at position 3. On the basis of non-destructive NMR analysis the following structure of repeat unit of the O-specific polysaccharide was established and confirmed independently by methylation analysis: -2)-beta-D-Glc-(1-->4)-beta-D-Glc-(1-->3)-beta-D-GlcNAc-(1-->4)-al fa-D-GalA-(1--> The serological investigation with application of P. penneri strain 42 anti O-serum has shown the activity of homologous preparations of LPS and PS, as well as cross-reactions with heterologous lipopolysaccharides from other Proteus strains.
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PMID:[Immunochemical studies of O-specific polysaccharide of Proteus penneri 42 lipopolysaccharide]. 823 52

Bacterial lipopolysaccharide (LPS) has been speculated to facilitate bacterial translocation by a mechanism involving physical disruption of the gut mucosal barrier. Polarized, cultured intestinal epithelial cells (Caco-2 cells) were used to study the effect of LPS on enterocyte structure, viability, and susceptibility to bacterial invasion. Varying concentrations of biologically active LPS were incubated with enterocytes for 1 and 16 hr. LPS had no noticeable effect on enterocyte viability or morphology, as measured by uptake of vital dyes, by distribution of cytoskeletal filamentous actin, and by visualization of subcellular ultrastructure. Transepithelial electrical resistance was similar in enterocyte cultures incubated with LPS for 1 hr, but there was a noticeable decrease after 16 hr, indicating a loss of epithelial integrity after prolonged exposure to LPS. The effect of LPS on bacterial uptake was studied using six strains of enteric bacteria with varying abilities to invade Caco-2 cells: Listeria monocytogenes, Salmonella typhimurium, Proteus mirabilis, Escherichia coli (2 strains), and Enterococcus faecalis. Electron microscopy showed enteric bacteria in intimate association with enterocyte apical microvilli, and internalized bacteria were consistently observed within cytoplasmic, membrane-bound vacuoles. Following a 1-hr incubation of individual strains of enteric bacteria with Caco-2 cells, numbers of viable intracellular bacteria varied significantly between individual bacterial strains, but numbers of intracellular bacteria were similar for each strain incubated with enterocytes exposed to 0, 10, and 100 micrograms LPS for 1 and 16 hr. Thus, although prolonged exposure to LPS might have some effect on enterocyte culture integrity (as measured by decreased electrical resistance), LPS had no discernible effect on enterocyte structure, viability, and susceptibility to bacterial invasion. These results suggested that LPS-induced bacterial translocation might not involve loss of epithelial viability, or facilitated entry of bacteria into intestinal epithelial cells.
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PMID:Effect of LPS on epithelial integrity and bacterial uptake in the polarized human enterocyte-like cell line Caco-2. 837 30

Mutations which severely affect the function of the outer membrane of Escherichia coli and Salmonella typhimurium (lpxA and firA mutations of lipid A synthesis and rfaE mutation of the lipopolysaccharide inner-core synthesis) were found to decrease the MICs of erythromycin, roxithromycin, clarithromycin, and azithromycin by factors of 32 to 512, 32 to 1,024, 64 to 512, and 16 to 64, respectively. The sensitization factors for three other hydrophobic antibiotics (rifampin, fusidic acid, and mupirocin) ranged from 16 to 300. The outer membrane permeability-increasing agents polymyxin B nonapeptide (3 micrograms/ml) and deacylpolymyxin B (1 microgram/ml) sensitized wild-type E. coli to azithromycin by factors of 10 and 30, respectively. Quantitatively very similar sensitization to the other macrolides took place. Polymyxin-resistant pmrA mutants of S. typhimurium displayed no cross-resistance to azithromycin. Proteus mirabilis mutants which were sensitized to polymyxin by a factor of > or = 300 to > or = 1,000 had a maximal two- to fourfold increase in sensitivity to azithromycin. These results indicate that azithromycin and the other new macrolides use the hydrophobic pathway across the outer membrane and that the intact outer membrane is an effective barrier against them. Furthermore, the results indicate that azithromycin, in contrast to polymyxin, does not effectively diffuse through the outer membrane by interacting electrostatically with the lipopolysaccharide.
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PMID:Outer membrane permeability barrier to azithromycin, clarithromycin, and roxithromycin in gram-negative enteric bacteria. 838 45

Swarming by Proteus mirabilis is characterized by cycles of rapid population migration across surfaces, following differentiation of typical vegetative rods into long, hyperflagellated, virulent swarm cells. A swarm-defective TnphoA insertion mutant was isolated that was not defective in cell motility, differentiation or control of the migration cycle, but was specifically impaired in the ability to undergo surface translocation as a multicellular mass. The mutation, previously shown to compromise urinary tract virulence, was located within a 1112 bp gene that restored normal swarming of the mutant when expressed in trans. The gene encoded a 40.6 kDa protein that is related to putative sugar transferases required for lipopolysaccharide (LPS) core modification in Shigella and Salmonella. The immediately distal open reading frame encoded a protein that is related to dehydrogenases involved in the synthesis of LPS O-side-chains, enterobacterial common antigen and extracellular polysaccharide (PS). Gel electrophoresis and electron microscopy showed that the mutant still made LPS but it had lost the ability to assemble a surface (capsular) PS, which gas-liquid chromatography and mass spectrometry indicated to be an acidic type II molecule rich in galacturonic acid and galactosamine. We suggest that this surface PS facilitates translocation of differentiated cell populations by reducing surface friction.
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PMID:A cell-surface polysaccharide that facilitates rapid population migration by differentiated swarm cells of Proteus mirabilis. 859 35

Several rough strains of Escherichia coli, Salmonella enterica and Proteus mirabilis were cultivated in the presence of (14C)acetate, which incorporated into their phospholipids and lipopolysaccharide. Phospholipids were removed from the cells with ethanol extraction. However, as shown by thin layer chromatography, methanol additionally extracted remarkable quantities of lipopolysaccharide from deep rough strains, but not from bacteria containing complete or nearly complete core.
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PMID:Methanol extracts LPS from deep rough bacteria. 860 6

The composition and structure of the O-specific polysaccharide chain of the bacterium Proteus mirabilis O26 lipopolysaccharide have been studied using one- and two-dimensional 1H- and 13C-NMR spectroscopy, including homonuclear correlation spectroscopy (COSY), H-detected 1H,13C heteronuclear multi-quantum coherence and rotating-frame nuclear Overhauser effect spectroscopy. It has been found that the polysaccharide is acidic due to the presence of D-galacturonic acid (D-GalA) residues, part of which are O-acetylated, while the other part form an amide with the alpha-amino group of L-lysine and is built up of tetrasaccharide repeating units having the following structure: [formula: see text] The P. mirabilis O26 polysaccharide is structurally similar to the O-specific polysaccharide of P. mirabilis O28 studied earlier by us and containing amides of D-galacturonic acid with L-lysine and L-serine.
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PMID:[Structure of a new lysine-containing O-specific polysaccharide from Proteus mirabilis O26]. 867 75


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