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B Jann

Publications and source records attributed to B Jann.

At least 19 recordsLinked to original sources
PubMed1992

The O18 antigens (lipopolysaccharides) of Escherichia coli. Structural characterization of the O18A, O18A1, O18B and O18B1-specific polysaccharides.

The O-specific polysaccharide moieties (PS) of the O18A, O18A1, O18B, and O18B1 antigens (lipopolysaccharides, LPS) consist of L-rhamnose (Rha), N-acetyl-D-glucosamine, D-galactose, and D-glucose in different molar ratios. By using chemical fragmentation, methylation, as well as one- and two-dimensional NMR spectroscopy, the structures of these polysaccharides were found to be [formula: see text] In O18A-PS and O18A1-PS x = 2, whereas in O18B-PS and in O18B11-PS x = 3. In all four polysaccharides alpha-D-Galp (residue D) is substituted at O-3. This substituent L (residue E) is beta-D-GlcpNAc-(1 in O18A-PS and O18A1-PS and it is alpha-D-Glcp-(1 in O18B-PS and O18B1-PS. Whereas there is no further substituent on the main chain of the O18A and O18B polysaccharides, in O18A1-PS and O18B1-PS the alpha-D-GlcpNAc residue A is substituted with alpha-Glcp-(1 (residue F), which is linked to O-6 in O18A1-PS and to O-4 in O18B1-PS. These results show that the O18 antigen comprises a group of four related LPS (O18A and O18B, with their glucosylated forms O18A1 and O18B1). The results are discussed with respect to epitope definition and biochemical implications.

Carbohydrate Conformation↗
PubMed1992

Structure of the Escherichia coli 0104 polysaccharide and its identity with the capsular K9 polysaccharide.

The 0104 antigen (lipopolysaccharide, LPS) of Escherichia coli has an acidic O specific polysaccharide. From the aqueous phase of a phenol water extraction of E. coli O104: K-, a fraction was obtained by ultracentrifugation and Cetavlon precipitation of the supernatant, which was enriched in long-chain LPS. Compositional analysis, NMR spectroscopy, periodate oxidation and methylation analysis showed that the polysaccharide chain of O104 LPS II consisted of galactose, N-acetylgalactosamine and neuraminic acid and acetate in the molar ratio of 2:1:1:1 and contained 3-beta Gal, 3-beta GalNAc, 4-alpha Gal, and 4-alpha(9-OAc-NeuNAc) in linear sequence. The same results were obtained with the capsular K9 polysaccharide from E. coli O9:K9, as presented here and reported previously (Dutton et al. (1987) Carbohydr. Res. 170, 193-206).

Bacterial Capsules↗
PubMed1992

Core-lipid A on the K40 polysaccharide of Escherichia coli O8:K40:H9, a representative of group I capsular polysaccharides.

From the capsular K40 polysaccharide of E. coli O8:K40:H9, a fraction was obtained by gel permeation chromatography which in SDS-PAGE exhibited a ladder-like pattern characteristic of lipopolysaccharides. In Western blots, this fraction reacted with a K40-specific antiserum but not with an O8-specific antiserum. It contained, in addition to the constituents of the K40 polysaccharide (glucuronic acid, glucosamine and serine), glucose, galactose, heptose, and KDO. Mild acid hydrolysis of this fraction liberated a lipid moiety which by chemical analysis was characterized as lipid A. From these results, we conclude that the capsular polysaccharide of E. coli O8:K40:H9 is in part bound to core lipid A. The significance of this finding is discussed.

Bacterial Capsules↗
PubMed1992

Structural studies of an emulsion-stabilizing exopolysaccharide produced by an adhesive, hydrophobic Rhodococcus strain.

The primary structure of an emulsion-stabilizing exopolysaccharide from the adhesive, hydrophobic Rhodococcus strain No. 33 was elucidated by NMR spectroscopy, methylation analyses, periodate oxidation and oligosaccharide analyses. The polysaccharide PS-33 consisted of rhamnose, galactose, glucose and glucuronic acid in molar ratios of 2:1:1:1. The main chain contained 3-substituted alpha-D-glucuronic acid linked to the 3-position at alpha-L-rhamnose, in addition to 3-substituted residues of beta-D-galactose and alpha-D-glucose. The alpha-L-rhamnose of the side chain was linked to position 4 of the galactose. In addition, the polysaccharide was O-acetylated, corresponding to one acetyl group per repeating unit. From the results two structural possibilities could be suggested. As the polysaccharide carries hydrophobic groups (methyl of rhamnose/O-acetyl), it is very likely that these are of general significance for the emulsifying activity of polysaccharides. It also seems to be possible that this polysaccharide is at least partially responsible for the hydrophobic cell surface properties of the Rhodococcus strain No. 33 and it may be involved in hydrophobic interactions when adhering to hydrophobic interfaces.

Bacterial Adhesion↗
PubMed1992

Structures of the O1B and O1C lipopolysaccharide antigens of Escherichia coli.

The O-specific moieties of the O1B antigen (lipopolysaccharide) from Escherichia coli O1B:K1 and the O1C antigen from E. coli O1C:K- both consist of L-rhamnose, D-galactose, N-acetyl-D-glucosamine, and N-acetyl-D-mannosamine in a molar ratio of 2:1:1:1. By using fragmentation procedures, methylation analysis, and one- and two-dimensional nuclear magnetic resonance spectroscopy, the structures of these polysaccharides were found to be [formula: see text] In the O1B polysaccharide X is 2, and in the O1C polysaccharide X is 3. With the recently published structure of the O1A polysaccharides (B. Jann, A. S. Shashkov, D. S. Gupta, S. M. Panasenko, and K. Jann, Carbohydr. Polym. 18:51-57 1992), three related O1 antigens are now known. Their common (O1-specific) epitope is suggested to be the side-chain N-acetyl-D-mannosamine residue.

Carbohydrate Sequence↗
PubMed1992

Capsules of Escherichia coli, expression and biological significance.

Escherichia coli may cause intestinal or extraintestinal infections. Generally, extraintestinal E. coli are encapsulated. The capsules are important virulence determinants, which enable the pathogenic bacteria to evade or counteract the unspecific host defense during the early (preimmune) phase of infection. They interfere with the action of complement and phagocytes. This effect is generally transient and overcome by capsule-specific antibodies in the immune phase of the host defense. In some cases, capsules are not or only poorly immunogenic, as a result of structural relationship or identity with host material. Strains with such capsules (e.g., K1 or K5) are very virulent. Bacterial capsules consist of acidic polysaccharides, which are made up from oligosaccharide repeating units. The capsules of E. coli are divided into two groups, which differ in chemistry, biochemistry, and genetic organization. All capsular polysaccharides are chromosomally determined: those of group I close to his and those of group II close to serA. The biosynthesis and surface expression have been extensively studied with representatives of group II capsular polysaccharides. It could be shown that their biosynthesis is directed from a gene block that determines the synthesis of the polysaccharide, its translocation across the cytoplasmic membrane, as well as its surface expression in a coordinate process. The chemical nature of group II capsular polysaccharides, as well as the mechanism(s) of their biosynthesis and expression, is presented.

Animals↗
PubMed1991

Structure of the capsular polysaccharide (K98 antigen) of E. coli O7:K98:H6.

The capsular polysaccharide (K98 antigen) of E. coli O7:K98:H6 contains rhamnose, glucuronic acid, and acetate in the molar ratios 3:1:0.6. Methylation analysis, oligosaccharide analysis, and 1D- and 2D-n.m.r. spectroscopy revealed the polysaccharide to be a glucuronic acid-substituted rhamnan with the structure [formula; see text] Of the 3-linked rhamnose residues, approximately 60% are O-acetylated at position 2.

Bacterial Capsules↗
PubMed1991

Genetic characterization of the O4 polysaccharide gene cluster from Escherichia coli.

The Escherichia coli O4 serotype is among those commonly isolated from urinary tract infections. In order to study the genetics of the O-antigen, the O4 biosynthesis genes from a uropathogenic E. coli have previously been cloned into E. coli K-12. A subclone, GH58, has been identified which reacts with antisera against the O4 serotype. In contrast to the wild-type parental strain, lipopolysaccharide (LPS) from this clone is devoid of rhamnose and does not cross-react with O18 antisera. The recombinant plasmid from GH58, pGH58, was used to transform the rfb deletion strain HU1190. The resultant strain agglutinates in O4 antisera, but produces unpolymerized LPS. Escherichia coli K-12 strains HB101 and RC712 containing pGH58 produce polymerized LPS, indicating that the genetic background of the host can influence the LPS encoded by recombinant molecules. A cosmid, pGH84, has been identified which encompasses the entire pGH58 gene sequences and includes an additional 34 kilobases of DNA. HU1190 containing this cosmid agglutinates in O4 antisera and produces a polymerized LPS. By constructing several deletion subclones of pGH84, we have localized the genes necessary for polymerized LPS to a 5.5 kb ClaI-BamHI fragment. P1 transductants that make polymerized and unpolymerized O4 LPS have also been identified.

Antigens, Bacterial↗
PubMed1991

Biosynthesis of the Escherichia coli K5 polysaccharide, a representative of group II capsular polysaccharides: polymerization in vitro and characterization of the product.

Biosynthesis of the capsular K5 polysaccharide of Escherichia coli, which has the structure 4)-beta GlcA-1,4-alpha GlcNAc-(1, was studied with membrane preparations from an E. coli K5 wild-type strain and from a recombinant K-12 strain expressing the K5 capsule. Polymerization occurs at the inner face of the cytoplasmic membrane without the participation of lipid-linked oligosaccharides. The serological K5 specificity of the in vitro product was determined with a K5-specific monoclonal antibody in an antigen-binding assay. The K5 polysaccharide, as obtained from the membranes after an in vitro incubation, has 2-keto-3-deoxyoctulosonic acid as the reducing sugar, which indicates that the polysaccharide grows by chain elongation at the nonreducing end.

Antigens, Bacterial↗
PubMed1990

Structure of the K24 antigen of E. coli O83:K24:H, a polymer that consists of alpha-Kdop and glycerol phosphate.

The structure of the K24 antigen of Escherichia coli O83:K24:H31 was elucidated by determination of composition and by 1H-, 13C-, and 31P-n.m.r. spectroscopy of the polymer and of a Kdo-glycerol (Gro) glycoside, obtained by mild alkaline hydrolysis and subsequent incubation with alkaline phosphatase. The K24 antigen has the repeating unit----7)-alpha-Kdop-(2----1)-Gro-(3-P. In the polymer, 56% of the repeating units are O-acetylated at C-4 of Kdo, approximately 28% at C-5 of Kdo, and approximately 16% are not acetylated.

Acetylation↗
PubMed1990

Structure and serological properties of the capsular K11 antigen of Escherichia coli O13:K11:H11.

The capsular K11 antigen of Escherichia coli contains glucose, fructose, and phosphate in the molar ratios 2:1:1, and a backbone of -4)-beta-D-glucopyranosyl-(1----4)-alpha-D-glucopyranosyl phosphate-(1----to which beta-D-fructofuranose is linked at position 3 of the beta-D-glucopyranosyl residue. The fructose, which is the immunodominant sugar of the K11 antigen, is released from the polysaccharide under mild acidic conditions (70 degrees, pH 5.0).

Antigens, Bacterial↗
PubMed1990

Molecular cloning and expression of the genes encoding the Escherichia coli K4 capsular polysaccharide, a fructose-substituted chondroitin.

The majority of capsular polysaccharides (K antigens) are linear molecules and their genes have a common functional organisation encoding common steps in capsule biogenesis. However, the K4 antigen is a substituted polymer composed of a chondroitin backbone with a fructose side chain. In order to determine whether K4 biosynthesis uses these common mechanisms the K4 antigen genes were cloned. DNA probes taken from the two conserved regions of the K1 genes were used to isolate one plasmid, pRD1, homologous to both probes. Immunological analysis was used to show that pRD1 directs the production of the substituted K4 antigen on the cell surface. Southern hybridisation was used to show that the cloned genes are organised in the same way as other K antigen gene clusters. We conclude that the branched K4 antigen is handled by the same post-polymerisation mechanisms as other linear K antigens.

Cloning, Molecular↗
PubMed1990

CMP-KDO-synthetase activity in Escherichia coli expressing capsular polysaccharides.

The temperature-regulated expression of capsular group II polysaccharides of Escherichia coli (B. Jann and K. Jann, (1990) Curr. Top. Microbiol. Immunol. 150: 19-42) depends on an elevated concentration of CMP-KDO, as evidenced by an increased activity of CMP-KDO synthetase. The increase in activity of CMP-KDO synthetase is observed only in cytoplasmic fractions of bacteria which had been grown at 37 degrees C but not after growth at 18 degrees C. The activity of CMP-KDO synthetase thus parallels the activity of the (membrane-associated) system synthesizing capsules of group II in E. coli. No such dependence of capsule expression on CMP-KDO was observed with E. coli with capsules of group I. A number of E. coli strains with capsular polysaccharides, which on the basis of genetic determination and chemical characteristics are considered as group II capsules, show no temperature regulation of their capsules and do not depend on an elevated CMP-KDO concentration for capsule expression. The capsular polysaccharides of these E. coli strains, which possibly represent a new group of E. coli capsules are tentatively classified as group I/II.

Escherichia coli↗
PubMed1990

Electron microscopic study of coexpression of adhesive protein capsules and polysaccharide capsules in Escherichia coli.

Escherichia coli 21535 (O21:K4:H4 with nonfimbrial adhesin NFA-6) and 21511 (O7:K98:H6 with nonfimbrial adhesin NFA-4) were analyzed by immunoelectron microscopy with a K98-specific antiserum and K4- and NFA-4-specific and NFA-6-reactive monoclonal antibodies. The bacteria were analyzed in ultrathin sections after stabilization of the capsules with specific antibodies by embedding in Epon 812 as well as in Lowicryl K4M. With the Lowicryl-embedded samples, the polysaccharide K antigens were labeled by the immunogold technique. It was found that with both strains all bacteria expressed the polysaccharide capsule, while in each case about 20% expressed the protein capsule in addition. Thus, in both invasive E. coli strains, bacteria are present which express composite capsules with the adhesin (recognition protein) at the cell-distal outer region and the K antigen (acidic polysaccharide) at the cell-proximal inner region. These findings are discussed with respect to the participation of the capsular compartments in unspecific host defense.

Adhesins, Escherichia coli↗
PubMed1990

Expression of the Escherichia coli K5 capsular antigen: immunoelectron microscopic and biochemical studies with recombinant E. coli.

The capsular K5 polysaccharide, a representative of group II capsular antigens of Escherichia coli, has been cloned previously, and three gene regions responsible for polymerization and surface expression have been defined (I. S. Roberts, R. Mountford, R. Hodge, K. B. Jann, and G. J. Boulnois, J. Bacteriol. 170:1305-1310, 1988). In this report, we describe the immunoelectron microscopic analysis of recombinant bacteria expressing the K5 antigen and of mutants defective in either region 1 or region 3 gene functions, as well as the biochemical analysis of the K5 capsular polysaccharide. Whereas the K5 clone expressed the K5 polysaccharide as a well-developed capsule in about 25% of its population, no capsule was observed in whole mount preparations and ultrathin sections of the expression mutants. Immunogold labeling of sections from the region 3 mutant revealed the capsular K5 polysaccharide in the cytoplasm. With the region 1 mutant, the capsular polysaccharide appeared associated with the cell membrane, and, unlike the region 3 mutant polysaccharide, the capsular polysaccharide could be detected in the periplasm after plasmolysis of the bacteria. Polysaccharides were isolated from the homogenized mutants with cetyltrimethylammonium bromide. The polysaccharide from the region 1 mutant had the same size as that isolated from the capsule of the original K5 clone, and both polysaccharides were substituted with phosphatidic acid. The polysaccharide from the region 3 mutant was smaller and was not substituted with phosphatidic acid. These results prompt us to postulate that gene region 3 products are involved in the translocation of the capsular polysaccharide across the cytoplasmic membrane and that region 1 directs the transport of the lipid-substituted capsular polysaccharide through the periplasm and across the outer membrane.

Antibodies, Monoclonal↗