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B Jann

Publications and source records attributed to B Jann.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1989

Novel change in the carbohydrate portion of Myxococcus xanthus lipopolysaccharide during development.

We have examined the alterations in lipopolysaccharide during aggregation and early development in Myxococcus xanthus. The lipopolysaccharide was isolated and characterized from cells developing on agar during glycerol induction and vegetative growth. A methylated amino sugar was identified as 6-O-methylgalactosamine by gas-liquid chromatography-mass spectrometry. This novel sugar was enriched in cells developing on agar.

Galactosamine↗
PubMed1988

Structure and serological characteristics of the capsular K4 antigen of Escherichia coli O5:K4:H4, a fructose-containing polysaccharide with a chondroitin backbone.

The chemical structure of the K4-specific capsular polysaccharide (K4 antigen) of Escherichia coli O5:K4:H4 was elucidated by composition, carboxyl reduction periodate oxidation methylation nuclear-magnetic-resonance spectroscopy and enzymatic cleavage. The polysaccharide consists of a backbone with the structure----3)-beta-D-glucuronyl-(1,4)-beta-D-N-acetylgalactosaminyl(1- to which beta-fructofuranose is linked at C-3 of glucuronic acid. Mild acid hydrolysis liberated fructose and converted the K4 antigen into a polysaccharide which has the same structure as chondroitin. The defructosylated polysaccharide was a substrate for hyaluronidase and chondroitinase. The serological reactivity of the K4 polysaccharide was markedly reduced after defructosylation.

Antigens, Bacterial↗
PubMed1988

Structure of the K74 antigen from Escherichia coli O44:K74:H18, a capsular polysaccharide containing furanosidic beta-KDO residues.

The structure of the capsular K74 antigen of E. coli H702c (O44:K74:H18) was elucidated by determination of the composition, 1H- and 13C-n.m.r. and c.d. spectroscopy, periodate oxidation, and methylation analysis of the polysaccharide and of a trisaccharide obtained by mild acid hydrolysis. The K74 antigen has the repeating unit----3)-beta-D-Ribf-(1----2)-beta-D-Ribf-(1----6)-beta-++ +KDOf-(2----. Of the repeating units, approximately 65% are O-acetylated, most probably at C-2 of the 3-linked ribose.

Acetylation↗
PubMed1988

Structure of the capsular K3 antigen of Escherichia coli 04:K3:H4, a polysaccharide containing a 4-deoxy-2-hexulosonic acid.

The K3-antigenic capsular polysaccharide (K3 antigen) of Escherichia coli contains L-rhamnose, a 4-deoxy-2-hexulosonic acid, and an O-acetyl group in the molar ratio of 3:1:1. The backbone consists of a ----2)-O-alpha-L-rhamnopyranosyl-(1----3)-O-alpha-L-rhamnopyranosyl-(1----3)-O-alpha-L-rhamnopyranosyl-(1---- repeating unit. Either one of the 3-linked L-rhamnopyranosyl residues of each repeating unit may be substituted at O-2 with a 4-deoxy-2-hexulosonic acid, an isomer of the furanosyl form of KDO, about 90% of which is acetylated at 0-6. The 4-deoxy-2-hexulosonic acid residue is linked to the L-rhamnan backbone in a very labile linkage which is split by 1% acetic acid (30 min, 100 degrees). The K3 polysaccharide has a molecular weight of approximately 38,000, corresponding to approximately 60 repeating units.

Antigens, Bacterial↗
PubMed1988

Comparative structural elucidation of the K18, K22, and K100 antigens of Escherichia coli as related ribosyl-ribitol phosphates.

The structures of the capsular K18, K22, and K100 antigens of E. coli O23:K18:H15, O23:K22:H15, and O75:K100:H5, respectively, were elucidated by determination of composition, 1H-, 13C-, and 31P-n.m.r. spectroscopy, periodate oxidation, alkaline hydrolysis followed by incubation with alkaline phosphatase, and methylation analysis of the polymers and their neutral fragmentation products. The polymers are poly(ribosyl-ribitol phosphates) related to the capsular antigen of H. influenzae (Hib). The K22 antigen has the repeating unit -P-2)-beta-Rib-(1----2)-RibOH-(5-, and the K18 antigen has the same polymer chain with partial 3-O-acetylation of the ribose moiety. The K100 antigen consists of repeating units of -P-3)-beta-Rib-(1----2)-RibOH-(5- and seems to have a secondary structure different from that of the other antigens. Together with the Hib capsular antigens, the structure of which was reported as -P-3)-beta-Rib-(1----1)-RibOH-(5-, these capsular antigens represent a structurally related group of capsular polymers.

Carbohydrate Conformation↗
PubMed1987

Nonfimbrial, mannose-resistant adhesins from uropathogenic Escherichia coli O83:K1:H4 and O14:K?:H11.

Nonfimbrial, mannose-resistant hemagglutinins (nonfimbrial adhesions [NFA] NFA-1 and NFA-2) were extracted from two agar-grown urinary isolates of Escherichia coli strains 827 (O83:K1:H4) and 54 (O14:K?:H11). The proteins were purified to homogeneity by ammonium sulfate precipitation and column chromatography. Nonfimbrial adhesins are soluble proteins, which tend to form aggregates of molecular weight above 10(6). NFA-1 and NFA-2 consist of subunits of 21,000 and 19,000 molecular weight, respectively. Both hemagglutinins caused hemagglutination of human erythrocytes and bound to human kidney cell monolayers. The binding of bacteria and hemagglutinins was assessed by using suitable antisera as detectors in an enzyme-linked immunosorbent assay. NFA-1 and NFA-2 inhibited the adherence of their respective strains to human kidney cells in a linear dose response. NFA-2 also inhibited heterologous strain adherence, but NFA-1 did not. Hemabsorption of bacterial suspension with erythrocytes at 4 degrees C, followed by differential centrifugation, enabled us to obtain a bacterial suspension lacking nonfimbrial adhesins in the supernatant and an adhesin-enriched bacterial suspension that was eluted from erythrocytes at 40 degrees C. Bacteria eluted from erythrocytes exhibited a higher adherence capacity than unfractionated cells. Bacteria of the fraction lacking adhesins did not adhere to human kidney cells. Electron microscope examinations showed the presence of an extracellular capsule-like layer in adhering E. coli 827, but not in nonadhering bacteria. E. coli 54 did not express the adhesin as a capsule. We conclude that E. coli 827 and 54 produce extracellular adhesins consisting of soluble proteins which are differently expressed and antigenically distinct. The adhesins seem to share a common receptor and mediate the adherence of two uropathogenic E. coli strains to epithelial cells.

Adhesins, Escherichia coli↗
PubMed1987

Lipopolysaccharides of Pseudomonas spp. that stimulate plant growth: composition and use for strain identification.

The outer membrane proteins of a series of fluorescent, root-colonizing, plant-growth-stimulating Pseudomonas spp. having been characterized (L. A. de Weger et al., J. Bacteriol. 165:585-594, 1986), the lipopolysaccharides (LPSs) of these strains were examined. The chemical composition of the LPSs of the three best-studied plant-growth-stimulating Pseudomonas strains WCS358, WCS361, and WCS374 and of P. aeruginosa PAO1 as a reference strain was determined and appeared to differ from strain to strain. The 2,6-dideoxy-2-aminosugar quinovasamine was the most abundant compound in the LPS of strain WCS358. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified LPS and of proteinase K-treated cell envelopes revealed ladderlike patterns for most of these strains. These patterns were not substantially influenced by differences in culture conditions. Analysis of proteinase K-treated cell envelopes of 24 root-colonizing Pseudomonas spp. revealed a unique band pattern for each strain, suggesting a great variety in the LPS structures present in these root colonizers. Therefore, electrophoretic analysis of LPS can be used for characterization and identification of the fluorescent root-colonizing Pseudomonas strains.

Electrophoresis, Polyacrylamide Gel↗
PubMed1986

Structure of the serine-containing capsular polysaccharide K40 antigen from Escherichia coli O8:K40:H9.

The structure of the K40 antigenic capsular polysaccharide (K40 antigen) of E. coli O8:K40:H9 was elucidated by determination of the composition, 1H- and 13C-n.m.r. spectroscopy, periodate oxidation and Smith degradation, and methylation analysis. The K40 polysaccharide consists of [(O-beta-D-glucopyranosyluronic acid)-(1----4)-O-(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-(1----6)-O -(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-(1----4)] repeating units. All of the glucuronic acid residues are substituted amidically with L-serine.

Carbohydrate Conformation↗