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N Strömberg

Publications and source records attributed to N Strömberg.

At least 19 recordsLinked to original sources
PubMed2005

Fluid- or surface-phase human salivary scavenger protein gp340 exposes different bacterial recognition properties.

Salivary scavenger receptor cysteine-rich protein gp340 aggregates streptococci and other bacteria as part of the host innate defense system at mucosal surfaces. In this article, we have investigated the properties of fluid-phase gp340 and hydroxylapatite surface-adsorbed gp340 in aggregation and adherence, respectively, of viridans group streptococci (e.g., Streptococcus gordonii and Streptococcus mutans), non-viridans group streptococci (e.g., Streptococcus pyogenes and Streptococcus suis), and oral Actinomyces. Fluid-phase gp340 and surface-phase gp340 bioforms were differentially recognized by streptococci, which formed three phenotypic groupings according to their modes of interaction with gp340. Group I streptococci were aggregated by and adhered to gp340, and group II streptococci preferentially adhered to surface-bound gp340, while group III streptococci were preferentially aggregated by gp340. Each species of Streptococcus tested was found to contain strains representative of at least two of these gp340 interaction groupings. The gp340 interaction modes I to III and sugar specificities of gp340 binding strains coincided for several species. Many gp340 interactions were sialidase sensitive, and each of the interaction modes (I to III) for S. gordonii was correlated with a variant of sialic acid specificity. Adherence of S. gordonii DL1 (Challis) to surface-bound gp340 was dependent upon expression of the sialic acid binding adhesin Hsa. However, aggregation of cells by fluid-phase gp340 was independent of Hsa and involved SspA and SspB (antigen I/II family) polypeptides. Conversely, both gp340-mediated aggregation and adherence of S. mutans NG8 involved antigen I/II polypeptide. Deletion of the mga virulence regulator gene in S. pyogenes resulted in increased cell aggregation by gp340. These results suggest that salivary gp340 recognizes different bacterial receptors according to whether gp340 is present in the fluid phase or surface bound. This phase-associated differential recognition by gp340 of streptococcal species of different levels of virulence and diverse origins may mediate alternative host responses to commensal or pathogenic bacterial phenotypes.

Actinomyces↗
PubMed2001

Gln-Gly cleavage: correlation between collision-induced dissociation and biological degradation.

Tryptic digestion of the 150-residue human acidic salivary proline-rich protein 1 (PRP-1) generated eight peptides, two of which corresponded to the N-terminal 30-residue segment. In each of the other six tryptic peptides, a consensus repeat with the structure PQGPPQQGG was present. A facile Gln-Gly cleavage between the second and the third residues of the repeat was observed during collision-induced dissociation experiments. We postulate possible mechanisms to account for this reactivity, involving attack on the peptidyl carbonyl group by the Gln sidechain. Significantly, the Gln-Gly cleavage has been shown to be biologically important in the bacterial degradation of PRPs in saliva, generating bacteria-binding Pro-Gln C-termini. We suggest a link between the gas-phase chemistry and the biochemical degradation of these molecules.

Amino Acid Sequence↗
PubMed2001

Different type 1 fimbrial genes and tropisms of commensal and potentially pathogenic Actinomyces spp. with different salivary acidic proline-rich protein and statherin ligand specificities.

Actinomyces spp. exhibit type 1 fimbria-mediated adhesion to salivary acidic proline-rich proteins (PRPs) and statherin ligands. Actinomyces spp. with different animal and tissue origins belong to three major adhesion types as relates to ligand specificity and type 1 fimbria genes. (i) In preferential acidic-PRP binding, strains of Actinomyces naeslundii genospecies 1 and 2 from human and monkey mouths displayed at least three ligand specificities characterized by preferential acidic-PRP binding. Slot blot DNA hybridization showed seven highly conserved type 1 fimbria genes (orf1- to -6 and fimP) in genospecies 1 and 2 strains, except that orf5 and orf3 were divergent in genospecies 1. (ii) In preferential statherin binding, oral Actinomyces viscosus strains of rat and hamster origin (and strain 19246 from a human case of actinomycosis) bound statherin preferentially. DNA hybridization and characterization of the type 1 fimbria genes from strain 19246 revealed a homologous gene cluster of four open reading frames (orfA to -C and fimP). Bioinformatics suggested sortase (orfB, orf4, and part of orf5), prepilin peptidase (orfC and orf6), fimbria subunit (fimP), and usher- and autotransporter-like (orfA and orf1 to -3) functions. Those gene regions corresponding to orf3 and orf5 were divergent, those corresponding to orf2, orf1, and fimP were moderately conserved, and those corresponding to orf4 and orf6 were highly conserved. Restriction fragment length polymorphism analyses using a fimP probe separated human and monkey and rat and hamster strains into phylogenetically different groups. (iii) In statherin-specific binding, strains of A. naeslundii genospecies 1 from septic and other human infections displayed a low-avidity binding to statherin. Only the orf4 and orf6 gene regions were highly conserved. Finally, rat saliva devoid of statherin bound bacterial strains avidly irrespective of ligand specificity, and specific antisera detected either type 1, type 2, or both types of fimbria on the investigated Actinomyces strains.

Actinomyces↗
PubMed2001

The association of bacterial adhesion with dental caries.

Saliva adhesion of bacteria is a key event in oral biofilm formation. Here, we used partial least-squares (PLS) analysis to correlate adhesion of cariogenic (Streptococcus mutans Ingbritt) and commensal (Actinomyces naeslundii LY7) model bacteria, and their agglutinin and acidic proline-rich protein ligands, respectively, with high and low caries experiences in 38 children reflecting today's skewed caries distribution. Adhesion of S. mutans was among the factors correlating strongest with high caries experience when PLS modeled together with traditional factors (e.g., sugar intake, lactobacilli counts). Saliva phenotypes with high agglutinin levels and Db-s (an acidic PRP variant) coincided with both high caries experience and S. mutans adhesion. A. naeslundii adhesion correlated with low caries experience. Non-Db phenotypes (i.e., acidic PRP-1 and PRP-2 variants) coincided with both low caries experience and S. mutans, but high A. naeslundii, adhesion. Thus, bacterial adhesion may modulate susceptibility and resistance to dental caries.

Actinomyces↗
PubMed2000

Salivary agglutinin, which binds Streptococcus mutans and Helicobacter pylori, is the lung scavenger receptor cysteine-rich protein gp-340.

Salivary agglutinin is a high molecular mass component of human saliva that binds Streptococcus mutans, an oral bacterium implicated in dental caries. To study its protein sequence, we isolated the agglutinin from human parotid saliva. After trypsin digestion, a portion was analyzed by matrix-assisted laser/desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), which gave the molecular mass of 14 unique peptides. The remainder of the digest was subjected to high performance liquid chromatography, and the separated peptides were analyzed by MALDI-TOF/post-source decay; the spectra gave the sequences of five peptides. The molecular mass and peptide sequence information showed that salivary agglutinin peptides were identical to sequences in lung (lavage) gp-340, a member of the scavenger receptor cysteine-rich protein family. Immunoblotting with antibodies that specifically recognized either lung gp-340 or the agglutinin confirmed that the salivary agglutinin was gp-340. Immunoblotting with an antibody specific to the sialyl Le(x) carbohydrate epitope detected expression on the salivary but not the lung glycoprotein, possible evidence of different glycoforms. The salivary agglutinin also interacted with Helicobacter pylori, implicated in gastritis and peptic ulcer disease, Streptococcus agalactiae, implicated in neonatal meningitis, and several oral commensal streptococci. These results identify the salivary agglutinin as gp-340 and suggest it binds bacteria that are important determinants of either the oral ecology or systemic diseases.

Agglutinins↗
PubMed2000

A novel Ser O-glucuronidation in acidic proline-rich proteins identified by tandem mass spectrometry.

Human acidic proline-rich salivary protein PRP-1 and its C-terminally truncated form PRP-3 were analyzed by electrospray tandem mass spectrometry. Post-translational modifications were detected and characterized. A pyroglutamic acid residue was demonstrated at the N-terminus, Ser-8 and Ser-22 were shown to be phosphorylated and an O-linked glucuronic acid conjugation was identified. The latter modification was located to Ser-17 and found to be present in approximately 40% of the polypeptides.

Amino Acid Sequence↗
PubMed2000

Adhesion of Candida albicans, but not Candida krusei, to salivary statherin and mimicking host molecules.

The aim of the present study was to identify salivary molecules affecting adhesion of Candida albicans and Candida krusei to salivary pellicles and epithelial cells. Strains of C. albicans (GDH18, GDH3339, CA1957, ATCC 28366 and ATCC 10321), but not C. krusei (strains ATCC 14243 and Ck9), bound to saliva-coated hydroxyapatite and buccal epithelial cells. Parotid saliva fractions containing statherin, glycosylated proline-rich proteins (PRP) and as yet unidentified components mediated adhesion of strain GDH18; Fuc alpha 1-2Gal beta 1-4Glc partly inhibited the adhesion to those fractions not containing statherin. Pure statherin, but not PRP-1, mediated dose-dependent adhesion of C. albicans strain GDH18 to hydroxyapatite beads. Candida isolates (GDH18, GDH3339 and CA1957) bound somewhat more avidly to statherin/saliva relative to ATCC strains 28366 and 10321, while the opposite was true for adhesion to buccal epithelial cells. Adhesion of C. albicans strain GDH18 to saliva-coated hydroxyapatite and buccal epithelial cells was completely (93%) and partly (43%) blocked by statherin-specific immunoglobulin G (IgG) antibodies, respectively. Control IgG antibodies did not block Candida adhesion. Blockage of Candida adhesion to epithelial cells also occurred with Fuc alpha 1-2Gal beta 1-4Glc (49%) and N-acetylglucosamine (38%), while statherin specific IgG antibodies in combination with Fuc alpha 1-2Gal beta 1-4Glc almost completely eliminated Candida adhesion (79%). In addition, statherin in solution blocked the adhesion of strain GDH18 to epithelial cells by inducing aggregation of Candida cells.

ABO Blood-Group System↗
PubMed2000

Possible release of an ArgGlyArgProGln pentapeptide with innate immunity properties from acidic proline-rich proteins by proteolytic activity in commensal streptococcus and actinomyces species.

This study suggests degradation of salivary acidic proline-rich proteins (PRPs) into potential innate-immunity-like peptides by oral Streptococcus and Actinomyces species. PRP degradation paralleled cleavage of Pro-containing substrates. PRP degradation by S. gordonii strain SK12 instantly released a Pyr(1)-Pro(104)Pro(105) and a Gly(111)-Pro(149)Gln(150) peptide together with a presumed Arg(106)Gly(107)Arg(108)Pro(109)Gln(110) pentapeptide. The synthetic Arg(106)Gly(107)Arg(108)Pro(109)Gln(110) peptide desorbed bound bacteria and counteracted sucrose-induced decrease of dental plaque pH in vitro.

Actinomyces↗
PubMed1999

Strains of Actinomyces naeslundii and Actinomyces viscosus exhibit structurally variant fimbrial subunit proteins and bind to different peptide motifs in salivary proteins.

Oral strains of Actinomyces spp. express type 1 fimbriae, which are composed of major FimP subunits, and bind preferentially to salivary acidic proline-rich proteins (APRPs) or to statherin. We have mapped genetic differences in the fimP subunit genes and the peptide recognition motifs within the host proteins associated with these differential binding specificities. The fimP genes were amplified by PCR from Actinomyces viscosus ATCC 19246, with preferential binding to statherin, and from Actinomyces naeslundii LY7, P-1-K, and B-1-K, with preferential binding to APRPs. The fimP gene from the statherin-binding strain 19246 is novel and has about 80% nucleotide and amino acid sequence identity to the highly conserved fimP genes of the APRP-binding strains (about 98 to 99% sequence identity). The novel FimP protein contains an amino-terminal signal peptide, randomly distributed single-amino-acid substitutions, and structurally different segments and ends with a cell wall-anchoring and a membrane-spanning region. When agarose beads with CNBr-linked host determinant-specific decapeptides were used, A. viscosus 19246 bound to the Thr42Phe43 terminus of statherin and A. naeslundii LY7 bound to the Pro149Gln150 termini of APRPs. Furthermore, while the APRP-binding A. naeslundii strains originate from the human mouth, A. viscosus strains isolated from the oral cavity of rat and hamster hosts showed preferential binding to statherin and contained the novel fimP gene. Thus, A. viscosus and A. naeslundii display structurally variant fimP genes whose protein products are likely to interact with different peptide motifs and to determine animal host tropism.

Actinomyces↗
PubMed1998

Actinomyces naeslundii genospecies 1 and 2 express different binding specificities to N-acetyl-beta-D-galactosamine, whereas Actinomyces odontolyticus expresses a different binding specificity in colonizing the human mouth.

A total of 102 strains of Actinomyces were isolated from teeth, buccal mucosa and tongue in eight individuals. The isolates were characterized by multivariate statistical analyses of phenotypic characteristics, serotyping and binding to beta-linked galactosamine (N-acetyl-beta-D-galactosamine) and acidic proline-rich protein structures. Based on these characteristics, isolates were classified into three major groups: (i) Isolates of Actinomyces naeslundii genospecies 2 were the dominant species on teeth and buccal mucosa and bound commonly to N-acetyl-beta-D-galactosamine (63 of 63 isolates) and acidic proline-rich proteins (63 of 63 isolates), regardless of tissue origin. They all exhibited a N-acetyl-beta-D-galactosamine binding specificity signified by N-acetyl-beta-D-galactosamine-inhibitable coaggregation with the streptococcal strains LVG1, GVE1, 24892 and MPB1; (ii) Isolates of A. naeslundii genospecies 1 were prevalent on teeth in certain individuals and bound commonly to N-acetyl-beta-D-galactosamine (20 of 20 isolates), but less commonly to acidic proline-rich proteins (5 of 20 isolates). They all possessed another N-acetyl-beta-D-galactosamine specificity, i.e. N-acetyl-beta-D-galactosamine-inhibitable coaggregation with the same streptococcal strains except for strain MPB1; (iii) Isolates of Actinomyces odontolyticus, the dominant species on the tongue (17 of 19 isolates), bound commonly to unknown structures on streptococci (17 of 19 isolates) but rarely to N-acetyl-beta-D-galactosamine (2 of 19 isolates) or acidic proline-rich proteins (3 of 19 isolates). In conclusion, A. naeslundii genospecies 1 and 2 exhibit different patterns of N-acetyl-beta-D-galactosamine and acidic proline-rich protein specificities to colonize dental and buccal mucosa surfaces, whereas A. odontolyticus utilizes another specificity to colonize the tongue.

Acetylgalactosamine↗
PubMed1998

Ribotype diversity of Actinomyces with similar intraoral tropism but different types of N-acetyl-beta-D-galactosamine binding specificity.

Sixty-three isolates of Actinomyces naeslundii genospecies 1 and 2 and Actinomyces odontolyticus from three subjects clustered into 22 ribotypes. Unique ribotypes were found in the subjects and within individual tissue sites (bucca, tooth and tongue). A odontolyticus ribotypes shared tongue-specific binding properties, while those of genospecies 1 and 2 from buccal and tooth surfaces shared different types of N-acetyl-beta-D-galactosamine binding specificity.

Acetylgalactosamine↗
PubMed1998

Actinomyces naeslundii displays variant fimP and fimA fimbrial subunit genes corresponding to different types of acidic proline-rich protein and beta-linked galactosamine binding specificity.

Actinomyces naeslundii genospecies 1 and 2 bind to acidic proline-rich proteins (APRPs) and statherin via type 1 fimbriae and to beta-linked galactosamine (GalNAcbeta) structures via type 2 fimbriae. In addition, A. naeslundii displays two types of binding specificity for both APRPs-statherin and GalNAcbeta, while Actinomyces odontolyticus binds to unknown structures. To study the molecular basis for these binding specificities, DNA fragments spanning the entire or central portions of fimP (type 1) and fimA (type 2) fimbrial subunit genes were amplified by PCR from strains of genospecies 1 and 2 and hybridized with DNA from two independent collections of oral Actinomyces isolates. Isolates of genospecies 1 and 2 and A. odontolyticus, but no other Actinomyces species, were positive for hybridization with fimP and fimA full-length probes irrespective of binding to APRPs and statherin, GalNAcbeta, or unknown structures. Isolates of genospecies 1 and 2, with deviating patterns of GalNAcbeta1-3Galalpha-O-ethyl-inhibitable coaggregation with Streptococcus oralis Ss34 and MPB1, were distinguished by a fimA central probe from genospecies 1 and 2, respectively. Furthermore, isolates of genospecies 1 and 2 displaying preferential binding to APRPs over statherin were positive with a fimP central probe, while a genospecies 2 strain with the opposite binding preference was not. The sequences of fimP and fimA central gene segments were highly conserved among isolates with the same, but diversified between those with a variant, binding specificity. In conclusion, A. naeslundii exhibits variant fimP and fimA genes corresponding to diverse APRP and GalNAcbeta specificities, respectively, while A. odontolyticus has a genetically related but distinct adhesin binding specificity.

Actinomyces↗
PubMed1998

Agglutinin and acidic proline-rich protein receptor patterns may modulate bacterial adherence and colonization on tooth surfaces.

Bacterial binding to salivary proteins may in part account for individual differences in the colonization of tooth surfaces. High-molecular-weight glycoproteins, agglutinins, mediate S. mutans adherence, whereas acidic proline-rich proteins mediate adherence of other early-colonizing streptococci and Actinomyces. The aim of the present study was to examine the composition of adherence-related salivary proteins and dental plaque micro-organisms in three individuals with a low, moderate, and high capacity to mediate S. mutans adherence. The S. mutans (strain Ingbritt) binding activity resided with a 300-kDa agglutinin which was six-fold more prevalent in the high S. mutans binding saliva compared with the low one. Binding to all three salivas was completely blocked by a monoclonal anti-agglutinin antibody. The moderate S. mutans binding saliva was found to contain adherence-inhibiting components. Furthermore, the low and moderate S. mutans binding salivas mediated binding of A. naeslundii strain LY7 to a greater extent than the saliva with high S. mutans binding. The A. naeslundii binding activity resided with the acidic proline-rich proteins (APRPs) and paralleled the relative content of 106- and 150-residue APRPs. Low A. naeslundii binding coincided with an almost two-fold higher ratio of 106/150 APRPs compared with the high A. naeslundii binding saliva. During conventional gel filtration, a degradation of the acidic, basic, and glycosylated proline-rich proteins was evident in the saliva with high S. mutans and low A. naeslundii binding. This saliva donor had a comparably high rate of dental plaque formation, high counts of S. mutans, and low counts of other streptococci and Actinomyces.

Actinomyces↗
PubMed1996

Studies on human minor salivary gland secretions using the Periotron method.

Secretions from minor salivary glands were estimated in 127 individuals by the Periotron method of measuring fluid output from different mucosal sites, and outputs were related to different variables. Large intra- and interindividual variations in secretions (expressed as microliter/cm2 per min) were observed, with means of 0.9 for the palatal, 4.8 for the labial and 16.0 for the buccal mucosal sites. Age had no influence on the secretion rate, but women had 10-20% lower values from all three sites than men (p < 0.05). Individuals wearing upper dentures or using tobacco had 300 and 27% increased palatal secretion rates, respectively (p < 0.001, p < 0.05). In addition, those being treated with diuretics had 15% lower rates of secretion from buccal mucosal glands (p < 0.05), and those complaining of oral dryness had 21% lower fluid output from the labial mucosa (p < 0.05). These results support the use of minor salivary glands in combination with the Periotron method to study mucosal secretions and functions.

Adult↗
PubMed1995

Detection of glycoprotein receptors on blotting membranes by binding of live bacteria and amplification by growth.

Conditions have been adapted for detecting bacteria bound to glycoprotein receptors on blotting membranes using a self-enhancing detection method based on bacterial growth. Neutrophil plasma membrane proteins, mediating adherence of mannose-binding type-1-fimbriated Escherichia coli and concanavalin A (Con A) to intact human neutrophils, were separated by SDS-PAGE and transferred onto a polyvinylidene difluoride (PVDF) membrane. The PVDF membrane was immersed in a suspension of mannose-binding type-1-fimbriated E. coli, and after repeated washings, bound bacteria were allowed to multiply into bacterial colonies by placing the membrane on a solid nutrient substratum. About one major and eight minor glycoproteins, some of which also were detected by Con A, selectively induced colony formation in a mannose-inhibitable fashion. Binding of [35S]methionine metabolically labeled E. coli to PVDF membranes produced a virtually identical binding pattern, demonstrating further the accuracy of this self-enhancing detection method which is rapid, simple, and sensitive and avoids radioisotopes.

Bacterial Adhesion↗
PubMed1995

Escherichia coli-induced activation of neutrophil NADPH-oxidase: lipopolysaccharide and formylated peptides act synergistically to induce release of reactive oxygen metabolites.

The prevailing view of neutrophil NADPH-oxidase activation during interaction with bacteria is that the production of toxic oxygen metabolites should be directed into the phagosome containing the engulfed prey. However, in this report we show that a common Escherichia coli strain, HB101, may induce a release of neutrophil oxygen metabolites to the extracellular milieu. This phenomenon is dependent on three factors: (i) the mobilization (upregulation) of neutrophil secretory vesicles prior to interaction with the bacteria, (ii) soluble bacterial factors binding to the formylmethionyl-leucyl-phenylalanine receptor and tentatively identified as formylated peptides, and (iii) a bacterium-associated priming factor identified as lipopolysaccharide.

Adult↗
PubMed1992

Actinomyces tissue specificity may depend on differences in receptor specificity for GalNAc beta-containing glycoconjugates.

Actinomyces naeslundii 12104 and A. viscosus LY7 were compared for receptor specificities and adherence properties because these relate to their oral colonization sites. Both strains bind GalNAc beta-containing glycosphingolipids (GSLs) in a GalNAc beta 1-3Gal alpha Oethyl-sensitive fashion but differ with respect to the number of cells bound to GSLs and the effect of neighboring sugar groups on the binding. Their hemagglutination and saccharide inhibition profiles confirms the existence of two receptor specificities (for example, when GalNAc beta 1-3Gal alpha Oethyl is multivalently conjugated to albumin, its inhibitory activity increases fourfold toward strain 12104 but decreases fourfold toward strain LY7). Trypsin or chymotrypsin treatment of human erythrocytes, which possess receptor GSLs, improves their hemagglutination with strain 12104. In contrast, the same treatment of chicken erythrocytes, which lack receptor GSLs, abolishes their hemagglutination. These findings suggest that both GSLs and glycoproteins act as functional receptors on eukaryotic cells. The strains also differ with respect to the following GalNAc beta 1-3Gal alpha Oethyl-sensitive adherence properties: (i) strain LY7 adheres somewhat better than does strain 12104 to buccal epithelial cells; (ii) in spite of their similar overall coaggregation patterns with streptococci, strain 12104 coaggregates with Streptococcus oralis MPB1 but strain LY7 does not; (iii) strain 12104 alone shows GalNAc beta-sensitive saliva aggregation and adherence to saliva-coated hydroxyapatite. The GSL binding patterns of fresh Actinomyces isolates reveal a high prevalence of LY7-like specificities among buccal isolates, whereas 12104-like specificities are most prevalent among plaque isolates. These findings strongly suggest that fresh Actinomyces isolates use fine specificity for GalNAc beta-containing glycoconjugates in recognition and subsequent colonization of specific oral surfaces.

Acetylgalactosamine↗