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N Strömberg

Publications and source records attributed to N Strömberg.

At least 37 records · Page 2Linked to original sources
PubMed1992

Salivary receptors for GalNAc beta-sensitive adherence of Actinomyces spp.: evidence for heterogeneous GalNAc beta and proline-rich protein receptor properties.

The receptors for GalNAc beta 1-3Gal alpha Oethyl (GalNAc beta)-sensitive adherence of Actinomyces strains to salivary pellicles were investigated. Parotid and submaxillary saliva from one individual was size fractionated and utilized in hydroxyapatite adherence assays with Actinomyces naeslundii 12104 and A. viscosus 19246 and LY7 with and without GalNAc beta. Three parotid salivary fractions, the high-molecular-weight, acidic proline-rich protein (PRP), and statherin fractions, promote GalNAc beta-sensitive adherence of strain 12104, whereas only the high-molecular-weight fraction of submaxillary saliva promotes such adherence. In contrast, strain LY7, possessing a variant GalNAc beta specificity, shows GalNAc beta-sensitive adherence to the leading and trailing regions of the submaxillary PRP fractions but less distinct adherence to the parotid and submaxillary high-molecular-weight fractions. In addition, the PRP and statherin fractions promote adherence of strains LY7 and 19246 that is not inhibited by GalNAc beta. However, whereas strain LY7 binds more strongly to the PRP fraction than to the statherin fraction, strain 19246 binds preferentially to the statherin fractions of parotid and submaxillary saliva. These salivary protein fractions were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunostained to detect glycosylated proteins. The different salivary receptor properties are paralleled by different glycosylation patterns. The variable GalNAc beta specificities may have evolved to match different salivary glycosylation patterns, and PRP and statherin binding properties seem to be heterogeneous among the Actinomyces strains.

Acetylgalactosamine↗
PubMed1991

Saccharide orientation at the cell surface affects glycolipid receptor function.

Three allelic variants of P-pilus-associated G-adhesins (lectins) with different cell-binding properties were recently described. Here we have analyzed Escherichia coli HB101 strains expressing the recombinant G-adhesin variants for their ability to agglutinate erythrocytes from various species as this relates to the glycosphingolipid (GSL) composition in the erythrocyte membranes. All three variants exhibit similar specificities for the globo-series GSLs affixed to artificial surfaces. However, only the PapGJ96 adhesin induces agglutination of erythrocytes having globotriaosylceramide (GbO3) [Gal(alpha 1-4)LacCer] as the major GSL. Furthermore, only PapGAD110 induces strong agglutination of erythrocytes having globotetraosylceramide (GbO4) [GalNAc(beta 1-3)Gal(alpha 1-4)LacCer] as the major GSL, while PrsGJ96 alone agglutinates those containing globopentaosylceramide (GbO5) [GalNAc(alpha 1-3)GalNAc(beta 1-3)Gal(alpha 1-4)LacCer]. Molecular modeling of these globo-GSLs demonstrates different saccharide orientations to the membrane surface for these isoreceptors. We suggest that the differential binding of the three G-adhesin variants results from differences in epitope presentation at the membrane among these globo-GSLs.

Adhesins, Escherichia coli↗
PubMed1990

Characterization of the binding of propionibacterium granulosum to glycosphingolipids adsorbed on surfaces. An apparent recognition of lactose which is dependent on the ceramide structure.

The binding properties of a strain of Propionibacterium granulosum derived from human skin was investigated with reference to glycosphingolipids separated on thin layer chromatograms or coated in microtiter wells using externally (125I) and metabolically [( 35S]methionine) labeled bacteria. Binding was found to lactosylceramide (LacCer; Gal beta 1-4Glc beta 1-Cer) but not to glycolipids lacking the lactose sequence (i.e. Glc beta 1-Cer, Gal beta 1-Cer or Gal alpha 1-4Gal beta 1-Cer). In microtiter wells, binding occurred at 50 ng and became half-maximal at the theoretical value for a monomolecular layer of LacCer (i.e. 100-200 ng/well). The bacteria also bound to glycolipids with various substitutions (e.g. GalNAc beta 1-4, Gal beta 1-3GalNAc beta 1-4, Fuc alpha 1-2Gal beta 1-3GalNAc beta 1-4, Gal alpha 1-3, GlcNAc beta 1-3, Gal beta 1-3GlcNAc beta 1-3, Gal beta 1-4GlcNAc beta 1-3, and Gal beta 1-3(Fuc alpha 1-4)GlcNAc beta 1-3) at the Gal of LacCer, although only those species with GalNAc beta 1-4 or Gal beta 1-3GalNAc beta 1-4 were as active as LacCer itself. Glycolipids with other additions (e.g. Gal alpha 1-4 and NeuAc alpha 2-3) were negative. For unsubstituted LacCer, the binding required either a trihydroxy base or 2-hydroxy fatty acid, specifying the epithelial type of ceramide; LacCer composed of a dihydroxy base and nonhydroxy fatty acid was negative. This is interpreted as indicating that the proper presentation of the binding epitope depends on the ceramide structure. The relevance of this to biological membranes has not yet been established. Neither free lactose (up to 20 mg/ml) nor lactose-bovine serum albumin (5 mg/ml) prevented the binding of bacteria to LacCer, two facts that support the solid-phase binding data demonstrating a low affinity binding and the crucial importance of a particular lactose epitope.

Adsorption↗
PubMed1990

Characterization of the binding of Actinomyces naeslundii (ATCC 12104) and Actinomyces viscosus (ATCC 19246) to glycosphingolipids, using a solid-phase overlay approach.

Actinomyces naeslundii (ATCC 12104) and Actinomyces viscosus (ATCC 19246) were radiolabeled externally (125I) or metabolically (35S) and analyzed for their ability to bind glycosphingolipids separated on thin layer chromatograms or coated in microtiter wells. Two binding properties were found and characterized in detail. (i) Both bacteria showed binding to lactosylceramide (LacCer) in a fashion similar to bacteria characterized earlier. The activity of free LacCer was dependent on the ceramide structure; species with 2-hydroxy fatty acid and/or a trihydroxy base were positive, while species with nonhydroxy fatty acid and a dihydroxy base were negative binders. Several glycolipids with internal lactose were active but only gangliotriaosylceramide and gangliotetraosylceramide were as active as free LacCer. The binding to these three species was half-maximal at about 200 ng of glycolipid and was not blocked by preincubation of bacteria with free lactose or lactose-bovine serum albumin. (ii) A. naeslundii, unlike A. viscosus, showed a superimposed binding concluded to be to terminal or internal GalNAc beta and equivalent to a lactose-inhibitable specificity previously analyzed by other workers. Terminal Gal beta was not recognized in several glycolipids, although free Gal and lactose were active as soluble inhibitors. The binding was half-maximal at about 10 ng of glycolipid. A glycolipid mixture prepared from a scraping of human buccal epithelium contained an active glycolipid with sites for both binding specificities.

Actinomyces↗
PubMed1990

Host-specificity of uropathogenic Escherichia coli depends on differences in binding specificity to Gal alpha 1-4Gal-containing isoreceptors.

Four G adhesins, cloned from uropathogenic Escherichia coli strains, were examined for binding to glycolipids and various eukaryotic cells. PapGAD110 and PapGIA2 showed virtually identical binding patterns to Gal alpha 1-4Gal-containing glycolipids, while PapGJ96 differed slightly and PrsGJ96 markedly with respect to the effect of neighbouring groups on the binding. Their hemagglutination patterns confirmed the existence of three receptor-binding specificities. While the PapG adhesins bound to uroepithelial cells from man (T24) but not to those from the dog (MDCK II), the reverse was true of PrsG. These binding patterns were largely explained by the absence or presence of appropriate glycolipid isoreceptors, although the inability of the PapG adhesins to bind MDCK II cells was attributed to an inappropriate presentation of their receptor epitopes. The high prevalence of PrsG-like specificities observed among wild-type dog uropathogenic E. coli isolates, together with the determined isoreceptor composition of human and dog kidney target tissues, suggest variation in receptor specificity as a mechanism for shifting host specificity, and that this variation has evolved in response to the topography of the host cellular receptors. The receptor-binding half proposed for the predicted amino acid sequences of the four G adhesins and the corresponding adhesin of one of the dog E. coli isolates varied considerably among the three receptor-binding groups of adhesins, but only little within each group.

Adhesins, Escherichia coli↗
PubMed1990

Carbohydrates as recognition molecules for bacterial adhesins: methodology and characteristics.

Future attempts at developing inhibitors of dental plaque formation necessitate characterization of the bacterial-host, as well as the inter-bacterial recognition processes. Bacterial binding to a panel of solid-phase reference glycolipids was used to reveal the recognition of internal receptor sequences, low-affinity cooperative interactions, and adhesin variants with slightly shifted receptor epitopes. This epitopic variation may be a mechanism for shifting the host and tissue tropism of the bacteria, and may have evolved in response to the topography and expression of receptor epitopes at the host tissue surfaces.

Actinomyces↗
PubMed1990

Erythrocyte gangliosides act as receptors for Neisseria subflava: identification of the Sia-1 adhesin.

Neisseria gonorrhoeae was recently shown to bind to a subset of lactose-containing glycolipids (N. Strömberg, C. Deal, G. Nyberg, S. Normark, M. So, and K.-A. Karlsson, Proc. Natl. Acad. Sci. USA 85:4902-4906, 1988). A number of commensal Neisseria strains were also shown to be lactose binders. In addition, Neisseria subflava bound to immobilized gangliosides, such as hematoside and sialosyl paragloboside, carrying the NeuAc alpha 2-3Gal beta 1-4Glc sequence. To a lesser extent, N. gonorrhoeae also bound to this receptor in vitro. In N. subflava GN01, this binding property mediated agglutination of human erythrocytes in a neuraminidase-sensitive fashion. Nitrosoguanidine-induced nonhemagglutinative mutants of N. subflava GN01 had lost the ability to bind hematoside and sialosylparagloboside but remained able to bind lactosylceramide and gangliotetraosylceramide. These mutants fell into three classes with respect to their outer membrane protein profiles in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Class 1 mutants were identical to the parent strain save for the loss of a 27-kilodalton (kDa) protein. Class 2 mutants showed an outer membrane protein profile identical to that of the wild type, whereas mutants belonging to class 3 showed a number of changes, including the apparent absence of the 27-kDa protein. The 27-kDa protein from N. subflava GN01 was purified from the supernatant. A polyclonal antiserum to the purified Sia-1 protein as well as a Sia-1-specific monoclonal antibody inhibited hemagglutination by strain GN01. The purified Sia-1 protein in the presence of diluted anti-Sia-1 antiserum mediated a neuraminidase-sensitive hemagglutination. The purified Sia protein from a class 2 mutant was not able to hemagglutinate when cross-linked with antibodies, suggesting that it is a mutant form of Sia-1 affected in the receptor-binding site. Immunoelectron microscopy with a Sia-1-specific monoclonal antibody revealed that the adhesin was nonfimbrial in nature, with aggregates of the adhesin extended out from the cells in a patchy fashion.

Agglutination Tests↗
PubMed1989

Novel isoglobo-neolacto-series hybrid glycolipid detected by a monoclonal antibody is a rat colon tumor-associated antigen.

Isoglobotetraosylceramide (GalNAc(beta 1-3)Gal(alpha 1-3)Gal(beta 1-4)Glc (beta 1-1)Cer), the major glycolipid species in dimethylhydrazine-induced rat tumors of colorectal origin, was not detected in epithelial cells of normal colon but was present in the non-epithelial stroma and could be extracted from each of nine tumors studied. Monoclonal antibodies produced against isoglobotetraosylceramide detected this and another novel rat tumor-associated glycolipid not present in epithelial cells nor in non-epithelial stroma of normal rat colon (Brodin, T., Thurin, J., Strömberg, N., Karlsson, K.-A. and Sjögren, H.O. (1985) Eur. J. Immunol. 16, 951-956). This novel glycolipid was present in 8/9 of the studied tumors and was also present in two in vitro cell clones. These were originally obtained from a W49/T4 colon tumor isograft. The novel glycolipid was characterized by mass spectrometry, 1H-NMR, and methylation analysis as a hybrid between the isoglobo- and neolacto-series, with the structure GalNAc(beta 1-3)Gal(alpha 1-3)Gal(beta 1-4)GlcNA(beta 1-3)Gal (beta 1-4)Glc(beta 1-1)Cer.

Animals↗
PubMed1988

Structures of the eight- to nine-sugar glycolipids of human blood group A erythrocytes.

Two glycolipid fractions, isolated in 1975 from blood group A1 erythrocytes and shown on the basis of direct-inlet mass spectrometry to contain eight- and nine-sugar A-type sequences, have been reinvestigated by fast-atom-bombardment mass spectrometry and overlay analysis with selected monoclonal anti-A antibodies. The presence of three separate glycolipids was concluded, consistent with a common paragloboside backbone [beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----3)-beta-D-Galp-(1----4)-D-Glc] and a typical erythrocyte ceramide component (sphingosine, and 22-, 23-, 24-, and 25-carbon nonhydroxy fatty acids). It is proposed that they carry A determinants based on Type 1 [beta-D-Galp-(1----3)-beta-D-GlcpNAc], Type 2 [beta-D-Galp-(1----4)-beta-D-GlcpNAc], and Type 3 [beta-D-Galp-(1----3)-alpha-D-GalpNAc] chains, respectively. The Type 1 (eight sugars) and Type 3 (nine sugars) glycolipids appeared in mixtures of both the native and the acetylated form. The existence of Type 1 glycolipid, which appears to be a genuine erythrocyte glycolipid as concluded from the ceramide composition, had been predicted earlier by other workers.

ABO Blood-Group System↗
PubMed1988

Studies on the binding of bacteria to glycolipids. Two species of Propionibacterium apparently recognize separate epitopes on lactose of lactosylceramide.

Two species of Propionibacterium were analysed regarding their binding to glycosphingolipids. Bacteria were labeled with 125I and selective interaction with glycolipids on thin-layer chromatograms was revealed by autoradiography. The carbohydrate site in common for active molecular species appeared to be lactose. The two bacteria differed, however, in the overall binding pattern on the chromatogram, probably due to recognition of separate epitopes on lactose. P. freudenreichii bound only to lactosylceramide while P. granulosum also recognized substituted lactosylceramide: Gal alpha 1----3Gal beta 1----4Glc beta Cer, GlcNAc beta 1----3Gal beta 1----4Glc beta Cer and Gal beta 1----3GlcNAc beta 1----3Gal beta 1----4Glc beta Cer were active, but Gal-alpha 1----4Gal beta 1----4Glc beta Cer was inactive. Also, there was an interesting dependence on ceramide structure in the case of lactosylceramide. P. freudenreichii bound to lactosylceramide with sphingosine and non-hydroxy fatty acids but not to species with sphingosine and 2-hydroxy fatty acids, phytosphingosine and non-hydroxy fatty acids or phytosphingosine and 2-hydroxy fatty acids. For P. granulosum the situation was reversed. This may be explained by an influence of ceramide structure on the presentation of the two lactose epitopes at the assay surface. These results were supported by curves from the binding of labeled bacteria to glycolipids coated in microtiter wells and in part by binding to glycolipid-coated chicken erythrocytes.

Animals↗
PubMed1988

Interaction of viruses, bacteria and bacterial toxins with host cell surface glycolipids. Aspects on receptor identification and dissection of binding epitopes.

An overview and perspective is presented on animal cell surface carbohydrate (primarily lipid-linked oligosaccharides) as specific receptors for viruses, bacteria and bacterial toxins. Although carbohydrate has been known for many years to be specific attachment sites for these ligands, it is only in very recent time that carbohydrate technology and receptor assays in combination afford a rational approach. One generalization from present experience is the property of microbiological ligands to recognize sequences placed internally in an oligosaccharide chain which differs from antibody recognition of short sequences which most often involves terminally placed determinants. This is of both biological and technical importance. Biologically it may assure attachment by avoiding differences between host individuals often residing in terminal parts (e.g. blood group determinants), and may also make a shift of target cells by mutations more efficient. Technically this property is an important help when dissecting narrow binding epitopes, and for disclosing receptor-binding variants with only slight differences in binding epitopes (e.g. different epitopes on the same disaccharide). Such variants representing a kind of "epitope drift" are probably a consequence of point mutations in the binding site of the lectin-like proteins to select a proper host environment. Current technology allows an efficient screening for carbohydrate receptors with interesting consequences for applications within medicine (diagnosis and therapy) and biotechnology.

Animals↗
PubMed1988

Glycolipids of human large intestine: difference in glycolipid expression related to anatomical localization, epithelial/non-epithelial tissue and the ABO, Le and Se phenotypes of the donors.

Human large intestine specimens were obtained during elective surgery from donors of known blood group ABO, Lewis and secretor phenotypes. The intestinal epithelial cells were isolated from the non-epithelial tissue in one case and in another case mucosa tissue was obtained by scraping. Total non-acid glycolipid and ganglioside fractions were isolated from the tissue specimens, analyzed by thin-layer chromatography and detected by chemical reagents and autoradiography after staining the plate with various blood group monoclonal antibodies and bacterial toxins. The amount of non-acid glycolipids present in the large intestine epithelial cells was 3.9 micrograms/mg of cell protein and in the non-epithelial tissue 0.39 mg/g dry tissue weight. The epithelial cells contained monoglycosylceramides and blood group Lea pentaglycosylceramides as major compounds together with small amounts of diglycosylceramides. In addition, trace amounts of tri- and tetra-glycosylceramides together with more complex glycolipids were present. The non-epithelial tissue contained mono-, di-, tri- and tetra-glycosylceramides as major non-acid components. Blood group ABH glycolipids were present in trace amounts in the non-epithelial part of the large intestine. Lea pentaglycosylceramide was the major blood group glycolipid present in all Le-positive individuals independent of the secretor status. Leb glycolipids were present in trace amounts in secretor individuals but completely lacking in non-secretors. Trace amounts of X antigens were found in all individuals, while Y antigens were only present in secretor individuals. The Lea, Leb, X and Y glycolipids were located in the epithelial cells. The gangliosides were present mainly in the non-epithelial tissue (65-350 nmol of sialic acid/g dry weight) and only trace amounts (less than 0.014 nmol/mg of cell protein) were found in the epithelial cells. The major gangliosides of the non-epithelial tissue were identified as GM3, GM1, GD3, GD1b, GT1b and GQ1b. In addition, several minor gangliosides were also present. Binding of cholera toxin to the thin-layer plate revealed trace amounts of the GM1 ganglioside in the epithelial cell ganglioside fraction.

ABO Blood-Group System↗
PubMed1988

Uropathogenic Escherichia coli can express serologically identical pili of different receptor binding specificities.

Uropathogenic Escherichia coli frequently express P-pilus adhesins that recognize Gal alpha (1-4)Gal-containing glycoconjugates. The P-pilus adhesin of the E. coli isolate J96 is encoded by the pap gene cluster and has been shown to agglutinate P1-erythrocytes. We now describe a novel gene cluster from J96, prs, which is responsible for the agglutination of sheep erythrocytes. The structurally related gene clusters both expressed pili exhibiting the F13 antigen. Analysis of mutants of cloned prs sequences, together with trans-complementation of pap and prs genes, identified the sheep-specific adhesin as the 37-kD PrsG protein. The prsG gene occupies the equivalent position in prs as occupied by papG, which specifies the Gal alpha (1-4)Gal-specific adhesin of pap. PrsG was shown to be structurally distinct from PapG since PapG-specific antiserum did not cross-react with PrsG. Using a solid phase glycolipid receptor binding assay, PrsG was found to specify preferential binding to the Forssman antigen, a major constituent of sheep erythrocyte membranes. The binding epitope was identified as the GaINAc alpha (1-3)GaINAc moiety. This is the first direct evidence that serologically identical pili may present antigenically distinct adhesins, each capable of binding to a specific receptor.

Adhesins, Escherichia coli↗
PubMed1987

The mono- and difucosyl blood group B glycosphingolipids of rat large intestine differ in type of core saccharide.

Two blood group B-active glycosphingolipids were isolated from rat large intestine and characterized by mass spectrometry, proton NMR spectroscopy and methylation analysis. The following structures were concluded: Gal alpha 1----3(Fuc alpha 1----2)Gal beta 1----3GlcNAc beta 1----3Gal beta 1----4Glc beta 1----1Cer and Gal alpha 1----3(Fuc alpha 1----2)Gal beta 1----4(Fuc alpha 1----3)GlcNAc beta 1----3Gal beta 1----4Glc beta 1----1Cer. The two glycolipids thus differ in their core saccharides (type 1 and type 2 chain, respectively) and therefore must have different pathways for biosynthesis.

ABO Blood-Group System↗
PubMed1987

Identification of the carbohydrate receptor for Shiga toxin produced by Shigella dysenteriae type 1.

The binding of Shiga toxin isolated from the bacterium Shigella dysenteriae type 1 to a series of glycolipids and to cells or cell homogenates has been studied. Bound toxin was detected using either 125I-labeled toxin or specific monoclonal antibody and 125I-labeled anti-antibody. Overlay of toxin on thin-layer chromatograms with separated glycolipids and binding to glycolipids coated in microtiter wells established that the toxin specifically bound to Gal alpha 1-4Gal beta (galabiose) placed terminally or internally in the oligosaccharide chain. No glycolipid shown to lack this sequence binds the toxin. Most of the glycolipids with internally placed galabiose were not active, indicating a sterical hindrance for toxin access to the binding epitope. Binding of toxin to HeLa cells in monolayers could be inhibited by preincubation of the toxin with galabiose covalently linked to bovine serum albumin (BSA), but not with free oligosaccharides containing galabiose or with lactose coupled to BSA. This demonstrated that the inhibition is specifically dependent on galabiose and requires multivalency of the disaccharide to be efficient. The inhibitory effect was successively enhanced by increasing the substitution on BSA (7, 18, and 25 mol of galabiose/mol of BSA). The BSA-coupled galabiose could also prevent the cytotoxic effect on HeLa cells (detachment of killed cells). There are cell lines with a dense number of receptor sites, but which are resistant to toxin action (uptake and inhibition of protein synthesis) which may suggest two types of receptor substances which are functionally different and unevenly expressed. In analogy with the mechanism earlier formulated for cholera toxin, we propose glycolipid-bound, bilayer-close galabiose as the functional receptor for membrane penetration of the toxin, while galabiose bound in glycoproteins affords binding sites but is not able to mediate penetration.

Bacterial Toxins↗
PubMed1986

Glycosphingolipid patterns of the gastrointestinal tract and feces of germ-free and conventional rats.

Acid and non-acid glycosphingolipids of stomach, small and large intestine, and stimulated feces of germ-free and conventional rats of the same stain have been isolated and characterized. The glycosphingolipid patterns of the intestinal organs were chemically and immunologically very similar between the two groups of rats and relatively unaffected by the presence of an intestinal microbial flora. The major exception was the presence of hematoside with N-glycoloylneuraminic acid (NeuGc) (NeuGc alpha 2----3Gal beta 1----4Glc beta 1----1Cer) in the stomach of conventional rats not found in the stomach of germ-free animals. Glycosphingolipids of stimulated feces of germ-free animals were derived from epithelial cells mainly of the small intestine and showed no signs of degradation. Glycosphingolipids of feces of conventional rats completely retained the pattern of blood group A-, B-, and H-active glycolipids as found in sterile feces but contained less of hematoside and more of lactosylceramide. This effect was probably due to degradation by bacteria, as demonstrated in vitro with the production of lactosylceramide after treatment of the isolated acid glycolipids of sterile feces with neuraminidase from Clostridium perfringens. The amount of total non-acid glycosphingolipids per dry weight was similar for stomach, was 50% higher for small intestine, and 300% higher for large intestine of germ-free animals compared to conventional animals. Due to the presence of large amounts of mucins the dry sterile feces contained 12% less non-acid glycolipids than conventional feces. However, calculated per rat per day the germ-free animal excreted more of non-acid glycosphingolipids (1.8 and 1.2 mg, respectively).

Animals↗