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

Sugar analysis and 1H- and 13C-NMR spectroscopic studies showed that various strains of Proteus mirabilis OXK used as antigens in the Weil-Felix test for serodiagnosis of rickettsiosis (scrub typhus) produce lipopolysaccharides (LPSs) with the same O-specific polysaccharide chain having the following structure: [formula: see text] where GlcA and GalA are glucuronic and galacturonic acids, respectively. This polysaccharide which defines the O3 specificity of Proteus and has been found earlier in an unclassified P. mirabilis strain S1959, contains an amide of D-galacturonic acid with L-lysine which plays an important role in manifesting the immunospecificity. A cross-reaction was observed in ELISA between sera from patients with scrub typhus, caused by the bacterium Orientia (Rickettsia) tsutsugamushi, and purified LPS of P. mirabilis OXK, thus suggesting that the common epitope involved in the Weil-Felix test is located on P. mirabilis OXK LPS. Rabbit anti-P. mirabilis OXK antibodies did not cross-react with LPS-lacking O. tsutsugamushi strain Gilliam in dot-blotting and Western blotting, and the nature of the rickettsial antigen responsible for the Weil-Felix reaction remains unknown.
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PMID:Structural and serological studies of the O-antigen of the bacterium Proteus mirabilis OXK (serogroup O3) used in the Weil-Felix test. 911 25

The mechanisms of interaction of the recombinant N-terminal portion of bactericidal/permeability-increasing protein, rBPI21, with various planar asymmetric and symmetric bilayer membranes, including the lipid matrix of the outer membrane of Gram-negative bacteria, were investigated via electrical measurements. For the lipopolysaccharide (LPS) leaflet of the outer membrane, isolated deep rough mutant LPS of Escherichia coli strain F515 (F515 LPS) and Proteus mirabilis strain R45 (R45 LPS) were used. The addition of rBPI21 to the LPS side of asymmetric LPS/phospholipid membranes, as well as to black lipid membranes made from dioleoylphosphatidylglycerol (DOPG), led to membrane rupture. The innermembrane potential difference resulted in a slight increase from 0 to 5 mV for symmetric DOPG membranes but changed for asymmetric F515 LPS/PL membranes from -36 to +8 mV and for R45 LPS/PL membranes from -37 to -5 mV following the addition of rBPI21. In all cases, the addition of rBPI21 led to an increase in membrane current. The effect of rBPI21 on the innermembrane potential difference of LPS/PL membranes was significantly reduced in the presence of 40 mM MgCl2 (shift from -36 to -31 mV for F515 LPS). On the basis of these results and from our studies on the interaction of rBPI21 with lipid monolayers and aggregates [Wiese, A., et al. (1997) Biochemistry 36, 10301-10310], a model is discussed explaining how the observed membrane rupture, increase of membrane current, and change of transmembrane potential as induced by rBPI21 may contribute to bacterial dysfunction.
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PMID:Mechanisms of action of bactericidal/permeability-increasing protein BPI on reconstituted outer membranes of gram-negative bacteria. 925 30

The structure of the O-specific polysaccharide chain of Proteus vulgaris OX19 lipopolysaccharide which determines the O1 specificity of Proteus and is used in the Weil-Felix test for diagnostics of rickettsiosis was established. On the basis of 1H- and 13 C-NMR spectroscopy, including two-dimensional correlation spectroscopy (COSY), H-detected 1H, 13C heteronuclear multiple-quantum coherence (HMQC), and rotating-frame nuclear Overhauser effect spectroscopy (ROESY), it was found that the polysaccharide consists of branched pentasaccharide repeating units containing D-galactose, 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose, and 2-acetamido-2,6-dideoxy-D-glucose (QuiNAc, two residues), which are connected to each other via a phosphate group (P): [formula: see text]. The polysaccharide is acid-labile, the glycosyl phosphate linkage being cleaved at pH 4.5 (70 degrees C) to give a phosphorylated pentasaccharide with a galactose residue at the reducing end. Structural analysis of the oligosaccharide and a product of its dephosphorylation with 48% hydrofluoric acid using 1H- and 13C-NMR spectroscopy and electrospray ionization mass spectrometry confirmed the structure of the polysaccharide.
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PMID:Structure of the acid-labile galactosyl phosphate-containing O-antigen of the bacterium Proteus vulgaris OX19 (serogroup O1) used in the Weil-Felix test. 927 85

An acidic O-specific polysaccharide was obtained by mild degradation of the lipopolysaccharide of the bacterium Proteus mirabilis O13 and found to contain D-galactose, 2-acetamido-2-deoxy-D-glucose, and N(epsilon)-(1-carboxyethyl)-N(alpha)-(D-galacturonoyl)lysine. On the basis of full acid hydrolysis and 1H- and 13C-NMR spectroscopy, including two-dimensional correlation spectroscopy (COSY), H-detected heteronuclear 1H, 13C multi-quantum coherence (HMQC), and rotating-frame nuclear Overhauser effect spectroscopy (ROESY), the following structure of the branched trisaccharide repeating unit of the polysaccharide was established [structure: see text]
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PMID:Structure of the O-specific polysaccharide of the bacterium Proteus mirabilis O13 containing a novel component: an amide of D-galacturonic acid with N(epsilon)-(1-carboxyethyl)lysine. 927 91

On the basis of sugar analysis and 1H- and 13C-NMR spectroscopy, it was shown that the O-specific polysaccharide of Proteus penneri strain 15 has a trisaccharide repeating unit, including an acetal-linked pyruvic acid residue, and is structurally identical to the capsular polysaccharide of Proteus vulgaris strain ATCC 49990. Serological studies supported this conclusion and demonstrated the presence in the homological antiserum of both anti-core and anti-O chain antibodies reacting with a lipopolysaccharide (LPS) epitope containing N-acetylglucosamine and galactose residues.
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PMID:Structural and immunochemical studies on the O-specific polysaccharide of Proteus penneri strain 15. 943 99

The lipopolysaccharides (LPSs) isolated from typhus group (TG) rickettsiae Rickettsia typhi and Rickettsia prowazekii were characterized by chemical analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by silver staining. LPSs from two species of TG rickettsiae contained glucose, 3-deoxy-D-manno-octulosonic acid, glucosamine, quinovosamine, phosphate, and fatty acids (beta-hydroxylmyristic acid and heneicosanoic acid) but not heptose. The O-polysaccharides of these LPSs were composed of glucose, glucosamine, quinovosamine, and phosphorylated hexosamine. Resolution of these LPSs by their apparent molecular masses by SDS-PAGE showed that they have a common ladder-like pattern. Based on the results of chemical composition and SDS-PAGE pattern, we suggest that these LPSs act as group-specific antigens. Furthermore, glucosamine, quinovosamine, and phosphorylated hexosamine were also found in the O-polysaccharide of the LPS from Proteus vulgaris OX19 used in the Weil-Felix test, suggesting that they may represent the antigens common to LPSs from TG rickettsiae and P. vulgaris OX19.
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PMID:Structural properties of lipopolysaccharides from Rickettsia typhi and Rickettsia prowazekii and their chemical similarity to the lipopolysaccharide from Proteus vulgaris OX19 used in the Weil-Felix test. 948 76

A marked serological cross-reactivity was observed by ELISA and a precipitation test between anti-Proteus mirabilis O23 serum and the lipopolysaccharide as well as the O-specific polysaccharide from the Proteus mirabilis strain belonging to serogroup O6. The structures of the O-specific polysaccharides were elucidated using chemical and NMR spectroscopic analyses, and the only common component, 2-acetamido-2-deoxy-beta-D-glucopyranose (beta-D-GlcNAc), was revealed, which was suggested to be responsible for the cross-reactivity observed. Both anti-O23 and anti-O6 sera were shown to react with 1, 3-Linked beta-D-GlcNAc-containing O-antigen from Salmonella enterica ssp. arizonae O59 also. The lack of reactivity of Smith-degraded P. mirabilis O6 O-specific polysaccharide with homologous antiserum indicated the crucial role of alpha-D-glucuronic acid in specific antibody binding.
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PMID:Structural and immunochemical studies of two cross-reactive Proteus mirabilis O-antigens, O6 and O23, containing beta1-->3-linked 2-acetamido-2-deoxy-D-glucopyranose residues. 952 74

The effects of the lipopolysaccharide (LPS) of Proteus mirabilis on the production of thiobarbituric acid reactive substances (TBARS) and the generation of superoxide radicals (O2) by pig blood platelets were studied in vitro. The effect of LPS on TBARS formation in platelets was dependent on the concentration of endotoxin. LPS at concentrations above 0.1 microg/10(8) platelets caused the production of TBARS concomitant with the generation of superoxide radicals. The responses of platelets to LPS suggest that endotoxin, like thrombin (a strong platelets agonist), stimulates an enzymatic cascade of platelet arachidonate via cyclooxygenase and produces thromboxane A2 (TXA2) concomitant with malonyldialdehyde (MDA).
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PMID:Response of blood platelets to Proteus mirabilis lipopolysaccharide. 952 79

We have studied the interaction of the polycationic peptide antibiotic polymyxin B (PMB) with asymmetric planar bilayer membranes via electrical measurements. The bilayers were of different compositions, including those of the lipid matrices of the outer membranes of various species of Gram-negative bacteria. One leaflet, representing the bacterial inner leaflet, consisted of a phospholipid mixture (PL; phosphatidylethanolamine, -glycerol, and diphosphatidylglycerol in a molar ratio of 81:17:2). The other (outer) leaflet consisted either of lipopolysaccharide (LPS) from deep rough mutants of PMB-sensitive (Escherichia coli F515) or -resistant strains (Proteus mirabilis R45), glycosphingolipid (GSL-1) from Sphingomonas paucimobilis IAM 12576, or phospholipids (phosphatidylglycerol, diphytanoyl-phosphatidylcholine). In all membrane systems, the addition of PMB to the outer leaflet led to the induction of current fluctuations due to transient membrane lesions. The minimal PMB concentration required for the induction of the lesions and their size correlated with the charge of the lipid molecules. In the membrane system resembling the lipid matrix of a PMB-sensitive strain (F515 LPS/PL), the diameters of the lesions were large enough (d = 2.4 nm +/- 8%) to allow PMB molecules to permeate (self-promoted transport), but in all other systems they were too small. A comparison of these phenomena with membrane effects induced by detergents (dodecyltriphenylphosphonium bromide, dodecyltrimethylammonium bromide, sodiumdodecylsulfate) revealed a detergent-like mechanism of the PMB-membrane interaction.
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PMID:Molecular mechanisms of polymyxin B-membrane interactions: direct correlation between surface charge density and self-promoted transport. 953 6

A neutral O-specific polysaccharide obtained from the lipopolysaccharide of Proteus penneri strain 26 was studied using sugar analysis and 1H and 13C NMR spectroscopy, including two-dimensional NMR techniques. The following structure of the trisaccharide repeating unit was established: -->6)-alpha-D-GlcpNAc-(1-->3)-alpha-L-QuipNAc-(1-->3)-alpha-D-Glcp NAc-(1--> where L-QuiNAc is 2-acetamido-2,6-dideoxy-L-glucose (N-acetyl-L-quinovosamine). Cross-reactivity of the Proteus penneri 26 anti-O serum with other strains of P. penneri isolated in Poland and USA and one strain of P. vulgaris is discussed.
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PMID:Structure and cross-reactivity of the O-specific polysaccharide of Proteus penneri strain 26, another neutral Proteus O-antigen containing 2-acetamido-2,6-dideoxy-L-glucose (N-acetyl-L-quinovosamine). 965 72


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