Structure of the O-specific polysaccharide of Asaia bogorensis ATCC BAA-21 lipopolysaccharide.

Asaia bogorensis is a Gram-negative bacterium isolated from flowers and fruits growing in tropical climate, reproductive system of mosquitoes, and rarely from immunocompromised patients. In Europe, A. bogorensis is responsible for the contamination of flavoured mineral waters.

The OL101 O antigen locus specifies a novel Klebsiella pneumoniae serotype O13 structure.

Klebsiella pneumoniae is one of the priority objects for the development of new therapies against infections. The species has been perceived as of limited variety of O antigens (11 O serotypes identified to date). That trait makes lipopolysaccharide an attractive target for protective antibodies.

First Report on the ( Biotype I) DSM 13808 Exopolysaccharide Structure.

subspecies , known as biotype I, is a facultative pathogen causing bacteraemia, infective endocarditis and sepsis that has been linked with colorectal cancer (CRC), but this correlation is still unclear. Bacterial surface structures, such as the major sugar antigens exposed to the outside of the microorganism, are potential virulence factors. One of the primary sugar antigens loosely attached to the cell surface is the biofilm component, exopolysaccharide (EPS).

The Mutation in Gene Cluster Selected by Phage-Borne Depolymerase Abolishes Capsule Production and Diminishes the Virulence of .

is considered one of the most critical multidrug-resistant pathogens and urgently requires new therapeutic strategies. Capsular polysaccharides (CPS), lipopolysaccharides (LPS), and exopolysaccharides (EPS) are the major virulence factors protecting against the immune response and thus may be targeted by phage-based therapeutics such as polysaccharides-degrading enzymes. Since the emergence of resistance to antibacterials is generally considered undesirable, in this study, the genetic and phenotypic characteristics of resistance to the phage-borne CPS-degrading depolymerase and its effect on virulence were investigated.

Parallelism of intestinal secretory IgA shapes functional microbial fitness.

Dimeric IgA secreted across mucous membranes in response to nonpathogenic taxa of the microbiota accounts for most antibody production in mammals. Diverse binding specificities can be detected within the polyclonal mucosal IgA antibody response, but limited monoclonal hybridomas have been studied to relate antigen specificity or polyreactive binding to functional effects on microbial physiology in vivo. Here we use recombinant dimeric monoclonal IgAs (mIgAs) to finely map the intestinal plasma cell response to microbial colonization with a single microorganism in mice.

Human Gb3/CD77 synthase produces P1 glycotope-capped N-glycans, which mediate Shiga toxin 1 but not Shiga toxin 2 cell entry.

The human Gb3/CD77 synthase, encoded by the A4GALT gene, is an unusually promiscuous glycosyltransferase. It synthesizes the Galα1→4Gal linkage on two different glycosphingolipids (GSLs), producing globotriaosylceramide (Gb3, CD77, P) and the P1 antigen. Gb3 is the major receptor for Shiga toxins (Stxs) produced by enterohemorrhagic Escherichia coli.

A New Look at the Enterobacterial Common Antigen Forms Obtained during Rough Lipopolysaccharides Purification.

Enterobacterial common antigen (ECA) is a conserved antigen expressed by enterobacteria. It is built by trisaccharide repeating units: →3)-α-D-Fuc4NAc-(1→4)-β-D-ManNAcA-(1→4)-α-D-GlcNAc-(1→ and occurs in three forms: as surface-bound linear polysaccharides linked to a phosphoglyceride (ECA) or lipopolysaccharide - endotoxin (ECA), and cyclic form (ECA). ECA maintains, outer membrane integrity, immunogenicity, and viability of enterobacteria.

Structural Studies of the Lipopolysaccharide Isolated from O22:H3 (CNCTC 90/89).

is a Gram-negative, rod-shaped bacterium which causes foodborne intestinal infections, including gastroenteritis. It is one of the most frequent causes of travellers' diarrhoea. Lipopolysaccharide (LPS, endotoxin), an important virulence factor of the species, is in most cases characterised by a smooth character, demonstrated by the presence of all regions, such as lipid A, core oligosaccharide, and O-specific polysaccharide, where the latter part determines O-serotype.

The Impact of Insertion Sequences on O-Serotype Phenotype and Its O-Locus-Based Prediction in O2 and O1.

is a nosocomial pathogen, pointed out by the World Helth Organisation (WHO) as "critical" regarding the highly limited options of treatment. Lipopolysaccharide (LPS, O-antigen) and capsular polysaccharide (K-antigen) are its virulence factors and surface antigens, determining O- and K-serotypes and encoded by O- or K-loci. They are promising targets for antibody-based therapies (vaccines and passive immunization) as an alternative to antibiotics.

Lipopolysaccharide-Linked Enterobacterial Common Antigen (ECA) Occurs in Rough Strains of R1, R2, and R4.

Enterobacterial common antigen (ECA) is a conserved surface antigen characteristic for . It is consisting of trisaccharide repeating unit, →3)-α-d-Fuc4NAc-(1→4)-β-d-ManNAcA-(1→4)-α-d-GlcNAc-(1→, where prevailing forms include ECA linked to phosphatidylglycerol (ECA) and cyclic ECA (ECA). Lipopolysaccharide (LPS)-associated form (ECA) has been proved to date only for rough phase II.

De‑O‑acylated lipooligosaccharide of E. coli B reduces the number of metastatic foci via downregulation of myeloid cell activity.

Lipopolysaccharides are the main surface antigens and virulence factors of gram‑negative bacteria. Removal of four ester‑bound fatty acid residues from hexaacyl lipid A of Escherichia coli lipooligosaccharide (LOS) resulted in the de‑O‑acylated derivative E. coli LOS‑OH (LOS‑OH).

Interactions of ficolin-3 with ovarian cancer cells.

Background: Ficolin-3 is a pattern-recognition molecule with the ability to activate the lectin pathway of complement. It is found in lung, liver and blood, but its physiological role is unclear. We have investigated interaction of recombinant ficolin-3 with malignant cells and tissues.

Interaction of Mannose-Binding Lectin With Lipopolysaccharide Outer Core Region and Its Biological Consequences.

Lipopolysaccharide (LPS, endotoxin), the main surface antigen and virulence factor of Gram-negative bacteria, is composed of lipid A, core oligosaccharide, and O-specific polysaccharide (O-PS) regions. Each LPS region is capable of complement activation. We have demonstrated that LPS of , an opportunistic human pathogen, reacts strongly with human and murine mannose-binding lectins (MBLs).

Cross-specificity of protective human antibodies against Klebsiella pneumoniae LPS O-antigen.

Humoral immune responses to microbial polysaccharide surface antigens can prevent bacterial infection but are typically strain specific and fail to mediate broad protection against different serotypes. Here we describe a panel of affinity-matured monoclonal human antibodies from peripheral blood immunoglobulin M-positive (IgM) and IgA memory B cells and clonally related intestinal plasmablasts, directed against the lipopolysaccharide (LPS) O-antigen of Klebsiella pneumoniae, an opportunistic pathogen and major cause of antibiotic-resistant nosocomial infections. The antibodies showed distinct patterns of in vivo cross-specificity and protection against different clinically relevant K.

Structure-Activity Relationship of Lipid A to the Production of TNF-α, IL-1β, and IL-6 by Human and Murine Macrophages.

is a Gram-negative bacterium that is associated with diarrheal disease in humans. Lipopolysaccharide (LPS) is the main surface antigen and virulence factor of this bacterium. The lipid A (LA) moiety of LPS is the main region recognized by target cells of immune system.

Discovery of monoclonal antibodies cross-reactive to novel subserotypes of K. pneumoniae O3.

Klebsiella pneumoniae is responsible for nosocomial infections causing significant morbidity and mortality. Treatment of newly emerging multi-drug resistant strains is hampered due to severely limited antibiotic choices. Passive immunization targeting LPS O-antigens has been proposed as an alternative therapeutic option, given the limited variability of Klebsiella O-antigens.

Identification of d-Galactan-III As Part of the Lipopolysaccharide of Serotype O1.

is a Gram-negative, ubiquitous bacterium capable of causing severe nosocomial infections in individuals with impaired immune system. Emerging multi-drug resistant strains of this species and particularly carbapenem-resistant strains pose an urgent threat to public health. The lipopolysaccharide (LPS) O-antigen is the main surface antigen.

A New Ligand-Based Method for Purifying Active Human Plasma-Derived Ficolin-3 Complexes Supports the Phenomenon of Crosstalk between Pattern-Recognition Molecules and Immunoglobulins.

Despite recombinant protein technology development, proteins isolated from natural sources remain important for structure and activity determination. Ficolins represent a class of proteins that are difficult to isolate. To date, three methods for purifying ficolin-3 from plasma/serum have been proposed, defined by most critical step: (i) hydroxyapatite absorption chromatography (ii) N-acetylated human serum albumin affinity chromatography and (iii) anti-ficolin-3 monoclonal antibody-based affinity chromatography.

Mycobacterial antigen 85 complex (Ag85) as a target for ficolins and mannose-binding lectin.

The pattern recognition molecules (PRMs) able to activate complement via the lectin pathway are suspected to be involved in the interaction between pathogenic Mycobacteria and the host immune response. Recently, we have found strong interactions between 25 and 35kDa mycobacterial cell fractions and mannose-binding lectin (MBL) and ficolins. Here we demonstrate that two biologically important mycobacterial structures, mannosylated lipoarabinomannan (ManLAM) and the antigen 85 (Ag85) complex, induce activation of the lectin pathway of complement.

Fractionation and analysis of lipopolysaccharide-derived oligosaccharides by zwitterionic-type hydrophilic interaction liquid chromatography coupled with electrospray ionisation mass spectrometry.

Lipopolysaccharide (LPS, endotoxin) is a main surface antigen and virulence factor of Gram-negative bacteria. Regardless of the source of LPS, this molecule, isolated from the smooth forms of bacteria, is characterised by a general structural layout encompassing three regions: (i) an O-specific polysaccharide (O-PS) - a polymer of repeating oligosaccharide units, (ii) core oligosaccharide (OS), and (iii) the lipid A anchoring LPS in the outer membrane of the cell envelope of Gram-negative bacteria. Structural analysis usually requires degradation of LPS and further efficient separation of various poly- and oligosaccharide glycoforms.

Both clades of the epidemic KPC-producing Klebsiella pneumoniae clone ST258 share a modified galactan O-antigen type.

Klebsiella pneumoniae ST258 is a globally disseminated, extremely drug resistant, nosocomial clone with limited treatment options. We show that the vast majority of ST258 isolates express modified d-galactan-I lipopolysaccharide O-antigen, termed hereinafter as D-galactan-III. The genetic determinant required for galactan-III synthesis was identified as a distinct operon adjacent to the rfb (wb) locus encoding D-galactan-I synthesis.

[The structure and significance of enterobacterial common antigen (ECA)].

The enterobacterial common antigen (ECA) is a carbohydrate-derived cell surface antigen present in all Gram-negative bacteria belonging to Enterobacteriaceae family. Biosynthetic pathways shared by ECA and LPS (endotoxin) suggest close connections between these antigens. ECA occurs in three different forms: a phosphatidyl-linked linear polysaccharide anchored on the cell surface (ECAPG), a cyclic form built of 4-6 repeating units localized in the periplasm (ECACYC) and as a linear polysaccharide covalently linked to LPS core oligosaccharide (ECALPS).

Core oligosaccharide of Escherichia coli B-the structure required for bacteriophage T4 recognition.

The structure of Escherichia coli B strain PCM 1935 core oligosaccharide has been investigated by (1)H and (13)C NMR spectroscopy, MALDI-TOF MS and ESI MS(n). It was concluded that the core oligosaccharide is a pentasaccharide with the following structure: ESI MS/MS analysis revealed that the glycine (a minor component) is linked to the →3,7)-l-α-d-Hepp-(1→ residue.