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

Murine monoclonal antibodies (MAbs) reacting with Pseudomonas syringae lipopolysaccharide (LPS) O polysaccharides (OPS) composed of tetra- and tri-alpha-D-rhamnose repeats in the backbone [3)D-Rha(alpha1-3)D-Rha(alpha1-2)D-Rha(alpha1-2)D-Rha(alpha1] and [3)D-Rha(alpha1-3)D-Rha(alpha1-2)D-Rha(alpha1] were generated and used for immunochemical analysis and for serological classification of the bacteria. A total of 195 of 358 P. syringae strains tested representing 21 pathovars were shown to share a common epitope, 1a, and were classified into serogroup O1. All strains with pathovars aptata, glycinea, japonica, phaseolicola, and pisi, most of the strains with pathovars atrofaciens and striafaciens, and half of the strains with pathovar syringae were classified into serotypes O1a', O1b, O1c, and O1d within serogroup O1. Serogroup-specific epitope 1a was inferred to be related to the (alpha1-2)D-Rha(alpha1-3) site of the OPS backbone. The serotype-specific epitopes 1b, 1c, 1d, and 1a' were inferred as relating to the immunodominant lateral (alpha1-3)D-Rha, (beta1-4)D-GlcNAc, and (alpha1-4)D-Fuc substituents and backbone-located site (alpha1-3)D-Rha(alpha1-2), respectively, of OPSs that share the common tetra-D-rhamnose repeats in the backbone. A total of 7.3% of the strains studied, all with pathovars morsprunorum and lapsa, were classified as serotypes O2a and O2d within serogroup 02. Serotype-specific epitope 2a was inferred as being related to the backbone-located site D-Rha(alpha1-3)D-Rha and epitope 2d to the immunodominant lateral (alpha1-4)D-Fuc residue of OPS consisting of tri-D-rhamnose repeats in the backbone. Epitope 2d alternated with 2a within the same LPS molecule and did not cross-react with epitope 1d. Serotypes O2a and O2d were observed in some strains correlating with the coexpression of the two chemotypes of OPS by the same strain. The serogroup O1-specific MAb Ps1a reacted weakly but definitely with all strains from serogroup 02. We propose serological formulas for serogroups O1 and 02 as well as for individual strains within these serogroups.
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PMID:Immunochemical characterization of O polysaccharides composing the alpha-D-rhamnose backbone of lipopolysaccharide of Pseudomonas syringae and classification of bacteria into serogroups O1 and O2 with monoclonal antibodies. 893 1

A polysaccharide containing D-galactose (Gal), 2-acetamido-2-deoxy-D-galactose (GalNAc), 2-acetamido-2-deoxy-D-glucose (GlcNAc), and 3-deoxy-3-(D-3-hydroxybutyramido)-D-quinovose (Qui3NR) was isolated from lipopolysaccharide (LPS) obtained from cells walls of the reference strain for Acinetobacter baumannii O23. By means of NMR studies, methylation analysis, and chemical degradations, the repeating unit of the polymer was identified as a branched pentasaccharide with the structure 1. The same polymer was apparently also present in LPS of the reference strain for serogroup O12, together with a second polymer based on a branched tetrasaccharide with the structure 2. This second polymer has previously been isolated as the O16 antigen of A. baumannii [Haseley, S.R., Diggle, H.J. & Wilkinson, S. G. (1996) Carbohydr. Res. 293, 259-265] and is probably present as a minor component of the LPS of A. baumannii O11 [Haseley, S.R. & Wilkinson, S.G. (1996) Eur. J. Biochem. 237, 266-271]. [Sequence: see text]
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PMID:Structures of polymeric products isolated from the lipopolysaccharides of reference strains for Acinetobacter baumannii O23 and O12. 906 58

The lpxC (envA) gene of Escherichia coli encodes UDP-3-O-acyl-GlcNAc deacetylase, the second and committed step of lipopolysaccharide biosynthesis. Although present in all gram-negative bacteria examined, the deacetylase from E. coli is the only example of this enzyme that has been expressed and purified. In order to examine other variants of this protein, we cloned the Pseudomonas aeruginosa deacetylase structural gene from a lambda library as a 5.1-kb EcoRI fragment. The LpxC reading frame encodes an inferred protein of 33,435 Da that is highly homologous to the E. coli protein and that possesses a nearly identical hydropathy profile. In order to verify function, we subcloned the P. aeruginosa lpxC gene into the T7-based expression vector pET11a. Upon induction at 30 degrees C, this construct yielded active protein to approximately 18% of the soluble fraction. We devised a novel, rapid, and reproducible assay for the deacetylase which facilitated purification of the enzyme in three steps. The purified recombinant protein was found to be highly sensitive to EDTA yet was reactivated by the addition of excess heavy metal, as was the case for crude extracts of P. aeruginosa. In contrast, deacetylase activity in crude extracts of E. coli was insensitive to EDTA, and the extracts of the envA1 mutant were sensitive in a time-dependent manner. The lpxC gene has no significant homology with amidase signature sequences. Therefore, we assign this protein to the metalloamidase family as a member with a novel structure.
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PMID:Cloning, expression, and purification of UDP-3-O-acyl-GlcNAc deacetylase from Pseudomonas aeruginosa: a metalloamidase of the lipid A biosynthesis pathway. 906 51

Water-soluble lipopolysaccharide (phenol/water extraction) isolated from Acinetobacter strain 90, which belongs to DNA group 10, was hydrolysed with 1% acetic acid, ultracentrifuged, and water-soluble products finally eluted from a Sephadex G-50 column. The major fraction, a polysaccharide, contained D-Gal, D-GlcNAc, D-GalNAc, and 4,6-dideoxy-4-[(R)-3-hydroxybutyramido]-D-galactose (Fuc4NBuOH). The polysaccharide was characterised by means of monosaccharide analyses, Smith-degradation, N-deacetylation/deamination, and NMR studies, and was shown to have a branched pentasaccharide repeating unit. [structure in text] This structure was specifically recognised in western blots and enzyme immunoassays by polyclonal rabbit antisera.
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PMID:Structural and serological characterisation of the O-antigenic polysaccharide of the lipopolysaccharide from Acinetobacter strain 90 belonging to DNA group 10. 915 81

The lipopolysaccharide of certain strains of Helicobacter pylori was recently shown to contain the Lewis X (Lex) trisaccharide (Galbeta-1, 4-(Fucalpha(1,3))-GlcNAc). Lex is an oncofetal antigen which appears on human gastric epithelium, and its mimicry by carbohydrate structures on the surface of H. pylori may play an important part in the interaction of this pathogen with its host. Potential roles for bacterial Lex in mucosal adhesion, immune evasion, and autoantibody induction have been proposed (Moran, A. P., Prendergast, M. M., and Appelmelk, B. J. (1996) FEMS Immunol. Med. Microbiol. 16, 105-115). In mammals, the final step of Lex biosynthesis is the alpha(1,3)-fucosylation of GlcNAc in a terminal Galbeta(1-->4)GlcNAc unit, and a corresponding GDP-fucose:N-acetylglucosaminyl alpha(1,3) fucosyltransferase (alpha(1,3)-Fuc-T) activity was recently discovered in H. pylori extracts. We used part of a human alpha(1, 3)-Fuc-T amino acid sequence to search an H. pylori genomic data base for related sequences. Using a probe based upon weakly matching data base sequences, we retrieved clones from a plasmid library of H. pylori DNA. DNA sequence analysis of the library clones revealed a gene which we have named fucT, encoding a protein with localized homology to the human alpha(1,3)-Fuc-Ts. We have demonstrated that fucT encodes an active Fuc-T enzyme by expressing the gene in Escherichia coli. The recombinant enzyme shows a strong preference for type 2 (e.g. LacNAc) over type 1 (e.g. lacto-N-biose) acceptors in vitro. Certain residues in a short segment of the H. pylori protein are completely conserved throughout the alpha(1,3)-Fuc-T family, defining an alpha(1,3)-Fuc-T motif which may be of use in identifying new fucosyltransferase genes.
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PMID:Lewis X biosynthesis in Helicobacter pylori. Molecular cloning of an alpha(1,3)-fucosyltransferase gene. 926 Nov 48

The lipopolysaccharide of Helicobacter mustelae type strain ATCC 43772 was obtained by phenol-water extraction of bacterial cells. Structural investigations were made on the lipid A free saccharide moiety released from the lipopolysaccharide by mild acetic acid hydrolysis. Nuclear magnetic resonance, gas liquid chromatography-mass spectrometry and fast atom bombardment-mass spectrometry were employed in the characterization of products from chemical manipulations. A monoclonal antibody specific for blood group A reacted strongly with lipopolysaccharide of H. mustelae. Chemical and serological data showed that the outer core region of the lipopolysaccharide from H. mustelae ATCC 43772 expresses the monofucosyl A type 1, alpha-D-GalNAc-(1-->3)-[alpha-L-Fuc-(1-->2]-beta-D-Gal-(1-->3)- beta-D-GlcNAc, blood group determinant, a mimic of animal cell surface glycolipids and glycoproteins.
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PMID:The lipopolysaccharide of Helicobacter mustelae type strain ATCC 43772 expresses the monofucosyl A type 1 histo-blood group epitope. 929 27

The O-specific polysaccharide isolated from the lipopolysaccharide (LPS) of Escherichia coli O121 by mild acid hydrolysis has been studied using mainly NMR spectroscopy. The polysaccharide was treated with mild base to yield a O-deacetylated polysaccharide which contained D-GlcNAc, D-GalNAcA, D-GalNAcAN (2-acetamido-2-deoxy-D-galacturonamide) and D-Qui4NAcGly (where D-Qui4N is 4-amino-4,6-dideoxy-D-glucose) in equimolar proportions. The presence of the amide was confirmed by recording the 1H NMR spectrum of the O-deacetylated polysaccharide at different pH values. The O-acetyl group was located on O-3 of the GalNAcAN and the structure of the polysaccharide can be written as [sequence: see text] This structure is almost identical to that previously reported for the O-specific polysaccharide of Shigella dysenteriae type 7 LPS, the only difference being that O-acetylation is stoichiometric in the latter.
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PMID:Structural studies on the Shigella-like Escherichia coli O121 O-specific polysaccharide. 937 37

We investigated the expression of the alpha- and beta-subunits of the lysosomal enzyme beta-N-acetylhexosaminidase in the BV-2 microglial cell line under different culture conditions. Beta-N-acetylhexosaminidase from BV-2 microglia cells was separated into its constituent isoenzymes on diethylaminoethyl (DEAE) cellulose, and its activity was monitored with 4-methylumbelliferyl-beta-N-acetylglucosamine and 4-methylumbelliferyl-beta-N-acetylglucosamine-6-sulphate substrates. Forms corresponding to the mouse isoenzymes A and B were present in the cells incubated in serum-supplemented medium as well as in serum-free medium. Lipopolysaccharide, a well-known activator of microglia in vitro, added to the BV-2 cells in serum-supplemented medium induced a decrease in the specific enzymatic activity determined with the 4-methylumbelliferyl-beta-N-acetylglucosamine substrate. Lipopolysaccharide had no effect on hexosaminidase isoenzyme pattern of BV-2 cells in serum-supplemented medium. The level of alpha-subunit mRNA was increased and the level of beta-subunit mRNA was decreased in BV-2 cells incubated in serum-supplemented medium plus lipopolysaccharide. In the cells incubated in a serum-free medium no significant changes in the hexosaminidase-specific activities towards the above substrates were observed. Interestingly, increased expression of alpha- and beta-subunit mRNA was evident in comparison with cultures in serum-supplemented medium. The present results suggest that the BV-2 cell line may be a useful tool to study the possible role of microglia in the metabolism of brain glycolipids.
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PMID:Constitutive expression of beta-N-acetylhexosaminidase in a microglial cell line: transcriptional modulation by lipopolysaccharide and serum factors. 937 92

Escherichia coli group I capsular K antigens are found in two forms on the cell surface. The K(LPS) form is linked to lipopolysaccharide lipid A core, whereas the high-molecular-weight capsular form is assembled independently of lipid A core. Subgroup IB K antigens are generally co-expressed with either the O8 or O9 antigen and, under the appropriate conditions, with the exopolysaccharide, colanic acid. To examine the relationships between the genetic loci and the synthetic pathways for these various cell-surface polymers, the gene cluster responsible for expression of a prototype group IB K antigen (serotype K40) was cloned and the flanking chromosomal regions characterized. Analysis of the six orfs within the cluster indicates features typical of Wzy (Rfc)-dependent O antigens. Synthesis of group IB K antigens is initiated by WecA (Rfe), a UDP-GlcNAc::undecaprenylphosphate GlcNAc-1-phosphate transferase, and the chain length of K40LPS is determined by the wzz gene product. The his-region of the E. coli O8:K40 prototype is almost exclusively devoted to the expression of three different surface polysaccharides. The rfbK40 cluster is located adjacent to the cps (colanic acid synthesis) and rfbO8 (O8 antigen synthesis) loci in the gene order: his-rfbO8/O9-wzz-ugd-gnd-rfbK40-galF-cps. Thus, rfbK40 is in the location occupied by other Wzy-dependent rfb gene clusters, and rfbO8/O9 represents an additional locus.
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PMID:Molecular and functional analysis of genes required for expression of group IB K antigens in Escherichia coli: characterization of the his-region containing gene clusters for multiple cell-surface polysaccharides. 938 97

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


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