51
|
Nobbs AH, Zhang Y, Khammanivong A, Herzberg MC. Streptococcus gordonii Hsa environmentally constrains competitive binding by Streptococcus sanguinis to saliva-coated hydroxyapatite. J Bacteriol 2007; 189:3106-14. [PMID: 17277052 PMCID: PMC1855861 DOI: 10.1128/jb.01535-06] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Competition between pioneer colonizing bacteria may determine polymicrobial succession during dental plaque development, but the ecological constraints are poorly understood. For example, more Streptococcus sanguinis than Streptococcus gordonii organisms are consistently isolated from the same intraoral sites, yet S. gordonii fails to be excluded and survives as a species over time. To explain this observation, we hypothesized that S. gordonii could compete with S. sanguinis to adhere to saliva-coated hydroxyapatite (sHA), an in vitro model of the tooth surface. Both species bound similarly to sHA, yet 10- to 50-fold excess S. gordonii DL1 reduced binding of S. sanguinis SK36 by 85 to >95%. S. sanguinis, by contrast, did not significantly compete with S. gordonii to adhere. S. gordonii competed with S. sanguinis more effectively than other species of oral streptococci and depended upon the salivary film on HA. Next, putative S. gordonii adhesins were analyzed for contributions to interspecies competitive binding. Like wild-type S. gordonii, isogenic mutants with mutations in antigen I/II polypeptides (sspAB), amylase-binding proteins (abpAB), and Csh adhesins (cshAB) competed effectively against S. sanguinis. By contrast, an hsa-deficient mutant of S. gordonii showed significantly reduced binding and competitive capabilities, while these properties were restored in an hsa-complemented strain. Thus, Hsa confers a selective advantage to S. gordonii over S. sanguinis in competitive binding to sHA. Hsa expression may, therefore, serve as an environmental constraint against S. sanguinis, enabling S. gordonii to persist within the oral cavity, despite the greater natural prevalence of S. sanguinis in plaque and saliva.
Collapse
Affiliation(s)
- Angela H Nobbs
- Department of Diagnostic and Biological Sciences, University of Minnesota, 17-164 Moos Tower, 515 Delaware Street, S.E., Minneapolis, MN 55455, USA
| | | | | | | |
Collapse
|
52
|
Young Lee S, Cisar JO, Bryant JL, Eckhaus MA, Sandberg AL. Resistance of Streptococcus gordonii to polymorphonuclear leukocyte killing is a potential virulence determinant of infective endocarditis. Infect Immun 2006; 74:3148-55. [PMID: 16714542 PMCID: PMC1479294 DOI: 10.1128/iai.00087-06] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Significant differences in virulence among seven representative Streptococcus gordonii strains were observed by using the rat model of infective endocarditis. Five strains, including S. gordonii DL1, caused severe disease, while the other two strains, including S. gordonii SK12, caused minimal or no disease. The differences in virulence were evident from the visible presence of streptococci in the vegetations present on the aortic valves of catheterized rats that were challenged with individual strains and also from the much greater recovery of rifampin-resistant S. gordonii DLl than of streptomycin-resistant S. gordonii SK12 from the hearts of animals coinfected with both organisms. Each S. gordonii strain aggregated with human platelets and bound to polymorphonuclear leukocytes (PMNs), as shown by the stimulation of PMN superoxide anion production. These interactions were reduced or abolished by pretreatment of the platelets or PMNs with sialidase, indicating that there was bacterial recognition of host sialic acid-containing receptors. Adhesin-mediated binding of each S. gordonii strain to PMNs also triggered phagocytosis. However, the subsequent PMN-dependent killing differed significantly for the seven strains. The five virulent strains included three strains that were not killed and two strains whose numbers were reduced by approximately 50%. In contrast, the level of killing of each avirulent strain under the same conditions was significantly greater and approached 90% of the bacteria added. Parallel studies performed with rat PMNs revealed comparable differences in the resistance or susceptibility of representative virulent and avirulent strains. Thus, the ability of S. gordonii to survive in PMNs following adhesin-mediated phagocytosis may be an important virulence determinant of infective endocarditis.
Collapse
Affiliation(s)
- Si Young Lee
- Oral Infection and Immunity Branch, NIDCR, NIH, Bethesda, MD 20892-4352, USA
| | | | | | | | | |
Collapse
|
53
|
Takahashi Y, Takashima E, Shimazu K, Yagishita H, Aoba T, Konishi K. Contribution of sialic acid-binding adhesin to pathogenesis of experimental endocarditis caused by Streptococcus gordonii DL1. Infect Immun 2006; 74:740-3. [PMID: 16369032 PMCID: PMC1346603 DOI: 10.1128/iai.74.1.740-743.2006] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An insertional mutation in hsa, the gene encoding the sialic acid-binding adhesin of Streptococcus gordonii DL1, resulted in a significant reduction of the infection rate of the organism and an inflammatory reaction in the rat aortic valve with experimental endocarditis, suggesting that the adhesin contributes to the infectivity of the organism for heart valves.
Collapse
Affiliation(s)
- Yukihiro Takahashi
- Department of Microbiology, Nippon Dental University School of Dentistry at Tokyo, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159, Japan.
| | | | | | | | | | | |
Collapse
|
54
|
Jakubovics NS, Kerrigan SW, Nobbs AH, Strömberg N, van Dolleweerd CJ, Cox DM, Kelly CG, Jenkinson HF. Functions of cell surface-anchored antigen I/II family and Hsa polypeptides in interactions of Streptococcus gordonii with host receptors. Infect Immun 2005; 73:6629-38. [PMID: 16177339 PMCID: PMC1230909 DOI: 10.1128/iai.73.10.6629-6638.2005] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus gordonii colonizes multiple sites within the human oral cavity. This colonization depends upon the initial interactions of streptococcal adhesins with host receptors. The adhesins that bind salivary agglutinin glycoprotein (gp340) and human cell surface receptors include the antigen I/II (AgI/II) family polypeptides SspA and SspB and a sialic acid-binding surface protein designated Hsa or GspB. In this study we determined the relative functions of the AgI/II polypeptides and Hsa in interactions of S. gordonii DL1 (Challis) with host receptors. For an isogenic mutant with the sspA and sspB genes deleted the levels of adhesion to surface-immobilized gp340 were reduced 40%, while deletion of the hsa gene alone resulted in >80% inhibition of bacterial cell adhesion to gp340. Adhesion of S. gordonii DL1 cells to gp340 was sialidase sensitive, verifying that Hsa has a major role in mediating sialic acid-specific adhesion to gp340. Conversely, aggregation of S. gordonii cells by fluid-phase gp340 was not affected by deletion of hsa but was eliminated by deletion of the sspA and sspB genes. Deletion of the AgI/II polypeptide genes had no measurable effect on hsa mRNA levels or Hsa surface protein expression, and deletion of hsa did not affect AgI/II polypeptide expression. Further analysis of mutant phenotypes showed that the Hsa and AgI/II proteins mediated adhesion of S. gordonii DL1 to human HEp-2 epithelial cells. Hsa was also a principal streptococcal cell surface component promoting adhesion of human platelets to immobilized streptococci, but Hsa and AgI/II polypeptides acted in concert in mediating streptococcal cell-platelet aggregation. The results suggest that Hsa directs primary adhesion events for S. gordonii DL1 (Challis) with immobilized gp340, epithelial cells, and platelets. AgI/II polypeptides direct gp340-mediated aggregation, facilitate multimodal interactions necessary for platelet aggregation, and modulate S. gordonii-host engagements into biologically productive phenomena.
Collapse
|
55
|
Takamatsu D, Bensing BA, Cheng H, Jarvis GA, Siboo IR, López JA, Griffiss JM, Sullam PM. Binding of theStreptococcus gordoniisurface glycoproteins GspB and Hsa to specific carbohydrate structures on platelet membrane glycoprotein Ibα. Mol Microbiol 2005; 58:380-92. [PMID: 16194227 DOI: 10.1111/j.1365-2958.2005.04830.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
GspB and Hsa are homologous serine-rich surface glycoproteins of Streptococcus gordonii strains M99 and Challis, respectively, that mediate the binding of these organisms to platelet membrane glycoprotein (GP) Ibalpha. Both GspB and Hsa consist of an N-terminal putative signal peptide, a short serine-rich region, a region (BR) that is rich in basic amino acids, a longer serine-rich region and a C-terminal cell wall anchoring domain. To further assess the mechanisms for GspB and Hsa binding, we investigated the binding of the BRs of GspB and Hsa (expressed as glutathione S-tranferase fusion proteins) to sialylated glycoproteins in vitro. Both fusion proteins showed significant levels of binding to sialylated moieties on fetuin and GPIbalpha. In contrast, the corresponding region of a GspB homologue of Streptococcus agalactiae, which is acidic rather than basic, showed no binding to either fetuin or GPIbalpha. As measured by surface plasmon resonance kinetic analysis, GspB- and Hsa-derived fusion proteins had high affinity for GPIbalpha, but with somewhat different dissociation constants. Dot blot analysis using a panel of synthesized oligosaccharides revealed that the BR of Hsa can bind both alpha(2-3) sialyllactosamine [NeuAcalpha(2-3)Galbeta(1-4)GlcNAc] and sialyl-T antigen [NeuAcalpha(2-3)Galbeta(1-3)GalNAc], whereas the BR of GspB only bound sialyl-T antigen. Moreover, far Western blotting using platelet membrane proteins revealed that GPIbalpha is the principal receptor for GspB and Hsa on human platelets. The combined results indicate that the BRs of GspB and Hsa are the binding domains of these adhesins. However, the subsets of carbohydrate structures on GPIbalpha recognized by the binding domains appear to be different between the two proteins.
Collapse
Affiliation(s)
- Daisuke Takamatsu
- Department of Medicine, Veterans Affairs Medical Center, University of California, San Francisco, CA 94121, USA
| | | | | | | | | | | | | | | |
Collapse
|
56
|
Plummer C, Wu H, Kerrigan SW, Meade G, Cox D, Ian Douglas CW. A serine-rich glycoprotein of Streptococcus sanguis mediates adhesion to platelets via GPIb. Br J Haematol 2005; 129:101-9. [PMID: 15801962 DOI: 10.1111/j.1365-2141.2005.05421.x] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Streptococcus sanguis is the most common oral bacterium causing infective endocarditis and its ability to adhere to platelets, leading to their activation and aggregation, is thought to be an important virulent factor. Previous work has shown that S. sanguis can bind directly to platelet glycoprotein (GP) Ib but the nature of the adhesin was unknown. Here, we have shown that a high molecular weight glycoprotein of S. sanguis mediates adhesion to glycocalacin. The bacterial glycoprotein was purified from cell extracts by chromatography on GPIb- and wheatgerm agglutinin affinity matrices and its interaction with GPIb was shown to be sialic acid-dependent. We designated the glycoprotein serine-rich protein A (SrpA). An insertional inactivation mutant lacking the SrpA of S. sanguis showed significantly reduced binding to glycocalacin, reduced adherence to platelets and a prolonged lag time to platelet aggregation. In addition, under flow conditions, platelets rolled and subsequently adhered on films of wild-type S. sanguis cells at low shear (50/s) but did not bind to films of the SrpA mutant. Platelets did not bind to wild-type bacterial cells at high shear (1500/s). These findings help to understand the mechanisms by which the organism might colonize platelet-fibrin vegetations.
Collapse
Affiliation(s)
- Christopher Plummer
- Department of Oral Pathology, School of Clinical Dentistry, University of Sheffield, Sheffield, UK
| | | | | | | | | | | |
Collapse
|
57
|
Bensing BA, López JA, Sullam PM. The Streptococcus gordonii surface proteins GspB and Hsa mediate binding to sialylated carbohydrate epitopes on the platelet membrane glycoprotein Ibalpha. Infect Immun 2004; 72:6528-37. [PMID: 15501784 PMCID: PMC523053 DOI: 10.1128/iai.72.11.6528-6537.2004] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Platelet binding by Streptococcus gordonii strain M99 is dependent on expression of the cell wall-anchored glycoprotein GspB. This large cell surface protein is exported from the M99 cytoplasm via a dedicated transport system that includes SecA2 and SecY2. GspB is highly similar to Hsa, a protein expressed by S. gordonii Challis that has been characterized as a sialic acid binding hemagglutinin. In this study, we compared the contribution of GspB and Hsa to the adherence of S. gordonii to selected glycoproteins. Our results indicate that GspB can mediate binding to a variety of sialylated glycoproteins. GspB facilitates binding to carbohydrates bearing sialic acid in either alpha(2-3) or alpha(2-6) linkages, with a slight preference for alpha(2-3) linkages. Furthermore, GspB readily mediates binding to sialic acid residues on immobilized glycocalicin, the extracellular portion of the platelet membrane glycoprotein (GP) Ibalpha (the ligand binding subunit of the platelet von Willebrand factor receptor complex GPIb-IX-V). Although Hsa is required for the binding of S. gordonii Challis to sialic acid, most of the Hsa expressed by Challis is retained in the cytoplasm. The deficiency in export is due, at least in part, to a nonsense mutation in secA2. Hsa export can be enhanced by complementation with secA2 from M99, which also results in significantly greater binding to sialylated glycoproteins, including glycocalicin. The combined results indicate that GspB and Hsa contribute similar binding capabilities to M99 and Challis, respectively, but there may be subtle differences in the preferred epitopes to which these adhesins bind.
Collapse
Affiliation(s)
- Barbara A Bensing
- Division of Infectious Diseases, Veterans Affairs Medical Center, University of California, San Francisco 94121, USA
| | | | | |
Collapse
|
58
|
|
59
|
Takahashi Y, Yajima A, Cisar JO, Konishi K. Functional analysis of the Streptococcus gordonii DL1 sialic acid-binding adhesin and its essential role in bacterial binding to platelets. Infect Immun 2004; 72:3876-82. [PMID: 15213130 PMCID: PMC427394 DOI: 10.1128/iai.72.7.3876-3882.2004] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial recognition of host sialic acid-containing receptors plays an important role in microbial colonization of the human oral cavity. The sialic acid-binding adhesin of Streptococcus gordonii DL1 was previously associated with the hsa gene encoding a 203-kDa protein. The predicted protein sequence consists of an N-terminal nonrepetitive region (NR1), including a signal sequence, a relatively short serine-rich region (SR1), a second nonrepetitive region (NR2), a long serine-rich region (SR2) containing 113 dodecapeptide repeats, and a C-terminal cell wall anchoring domain. In the present study, the contributions of SR1, NR2, and SR2 to Hsa-mediated adhesion were assessed by genetic complementation. Adhesion of an hsa chromosomal deletion mutant to sialic acid-containing receptors was restored by plasmids containing hsa constructs encoding Hsa that lacked either the N- or C-terminal portion of SR2. In contrast, hsa constructs that lacked the coding sequences for SR1, NR2, or the entire SR2 region failed to restore adhesion. Surface expression of recombinant Hsa was not affected by removal of SR1, NR2, or a portion of SR2 but was greatly reduced by complete removal of SR2. Wheat germ agglutinin, a probe for Hsa-specific glycosylation, reacted with recombinant Hsa lacking SR1, NR2, or SR2 but not with recombinant Hsa lacking both SR1 and SR2. Significantly, the aggregation of human platelets by S. gordonii DL1, an interaction implicated in the pathogenesis of infective endocarditis, required the expression of hsa. Moreover, neuraminidase treatment of the platelets eliminated this interaction, further supporting the hypothesis that Hsa plays an essential role in the bacterium-platelet interaction.
Collapse
Affiliation(s)
- Yukihiro Takahashi
- Department of Microbiology, The Nippon Dental University School of Dentistry at Tokyo, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159, Japan.
| | | | | | | |
Collapse
|
60
|
Love RM, Jenkinson HF. Invasion of dentinal tubules by oral bacteria. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 2003; 13:171-83. [PMID: 12097359 DOI: 10.1177/154411130201300207] [Citation(s) in RCA: 281] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bacterial invasion of dentinal tubules commonly occurs when dentin is exposed following a breach in the integrity of the overlying enamel or cementum. Bacterial products diffuse through the dentinal tubule toward the pulp and evoke inflammatory changes in the pulpo-dentin complex. These may eliminate the bacterial insult and block the route of infection. Unchecked, invasion results in pulpitis and pulp necrosis, infection of the root canal system, and periapical disease. While several hundred bacterial species are known to inhabit the oral cavity, a relatively small and select group of bacteria is involved in the invasion of dentinal tubules and subsequent infection of the root canal space. Gram-positive organisms dominate the tubule microflora in both carious and non-carious dentin. The relatively high numbers of obligate anaerobes present-such as Eubacterium spp., Propionibacterium spp., Bifidobacterium spp., Peptostreptococcus micros, and Veillonella spp.-suggest that the environment favors growth of these bacteria. Gram-negative obligate anaerobic rods, e.g., Porphyromonas spp., are less frequently recovered. Streptococci are among the most commonly identified bacteria that invade dentin. Recent evidence suggests that streptococci may recognize components present within dentinal tubules, such as collagen type I, which stimulate bacterial adhesion and intra-tubular growth. Specific interactions of other oral bacteria with invading streptococci may then facilitate the invasion of dentin by select bacterial groupings. An understanding the mechanisms involved in dentinal tubule invasion by bacteria should allow for the development of new control strategies, such as inhibitory compounds incorporated into oral health care products or dental materials, which would assist in the practice of endodontics.
Collapse
Affiliation(s)
- R M Love
- Department of Stomatology, University of Otago School of Dentistry, PO Box 647, Dunedin, New Zealand.
| | | |
Collapse
|
61
|
Rickard AH, Gilbert P, High NJ, Kolenbrander PE, Handley PS. Bacterial coaggregation: an integral process in the development of multi-species biofilms. Trends Microbiol 2003; 11:94-100. [PMID: 12598132 DOI: 10.1016/s0966-842x(02)00034-3] [Citation(s) in RCA: 445] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Coaggregation is a process by which genetically distinct bacteria become attached to one another via specific molecules. Cumulative evidence suggests that such adhesion influences the development of complex multi-species biofilms. Once thought to occur exclusively between dental plaque bacteria, there are increasing reports of coaggregation between bacteria from other biofilm communities in several diverse habitats. A general role for coaggregation in the formation of multi-species biofilms is discussed.
Collapse
Affiliation(s)
- Alexander H Rickard
- School of Pharmacy, University of Manchester, Coupland III Building, Oxford Road, Manchester M13 9PL, UK.
| | | | | | | | | |
Collapse
|
62
|
Tronchin G, Esnault K, Sanchez M, Larcher G, Marot-Leblond A, Bouchara JP. Purification and partial characterization of a 32-kilodalton sialic acid-specific lectin from Aspergillus fumigatus. Infect Immun 2002; 70:6891-5. [PMID: 12438366 PMCID: PMC133100 DOI: 10.1128/iai.70.12.6891-6895.2002] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2002] [Revised: 08/28/2002] [Accepted: 09/16/2002] [Indexed: 11/20/2022] Open
Abstract
Adherence of the opportunistic fungus Aspergillus fumigatus to the extracellular matrix components is considered a crucial step in the establishment of the infection. Given the high carbohydrate content of these glycoproteins and the role of carbohydrate-protein interactions in numerous adherence processes, the presence of a lectin in A. fumigatus was investigated. Different fungal extracts obtained by sonication or grinding in liquid nitrogen from resting or swollen conidia, as well as from germ tubes and mycelium, were tested by hemagglutination assays using rabbit erythrocytes. A lectin activity was recovered in all the extracts tested. However, sonication of resting conidia resulted in the highest specific activity. Purification of the lectin was achieved by gel filtration followed by ion-exchange and hydrophobic-interaction chromatographies. Analysis of the purified lectin by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed an apparent molecular mass of 32 kDa, which is similar to that of the alkaline protease already identified from different strains of A. fumigatus. However, as evidenced by the use of an alkaline protease-deficient mutant, the two activities were supported by distinct proteins. In addition, hemagglutination inhibition experiments using different saccharides and glycoproteins demonstrated the specificity of the lectin for sialic acid residues. Together these results suggest that this lectin may contribute to the attachment of conidia to the extracellular matrix components through the recognition of the numerous terminal sialic acid residues of their carbohydrate chains.
Collapse
Affiliation(s)
- Guy Tronchin
- Groupe d'Etude des Interactions Hôte-Parasite, UPRES EA 3142, Laboratoire de Parasitologie-Mycologie, Centre Hospitalier Universitaire, Angers, France.
| | | | | | | | | | | |
Collapse
|
63
|
Kolenbrander PE, Andersen RN, Blehert DS, Egland PG, Foster JS, Palmer RJ. Communication among oral bacteria. Microbiol Mol Biol Rev 2002; 66:486-505, table of contents. [PMID: 12209001 PMCID: PMC120797 DOI: 10.1128/mmbr.66.3.486-505.2002] [Citation(s) in RCA: 606] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Human oral bacteria interact with their environment by attaching to surfaces and establishing mixed-species communities. As each bacterial cell attaches, it forms a new surface to which other cells can adhere. Adherence and community development are spatiotemporal; such order requires communication. The discovery of soluble signals, such as autoinducer-2, that may be exchanged within multispecies communities to convey information between organisms has emerged as a new research direction. Direct-contact signals, such as adhesins and receptors, that elicit changes in gene expression after cell-cell contact and biofilm growth are also an active research area. Considering that the majority of oral bacteria are organized in dense three-dimensional biofilms on teeth, confocal microscopy and fluorescently labeled probes provide valuable approaches for investigating the architecture of these organized communities in situ. Oral biofilms are readily accessible to microbiologists and are excellent model systems for studies of microbial communication. One attractive model system is a saliva-coated flowcell with oral bacterial biofilms growing on saliva as the sole nutrient source; an intergeneric mutualism is discussed. Several oral bacterial species are amenable to genetic manipulation for molecular characterization of communication both among bacteria and between bacteria and the host. A successful search for genes critical for mixed-species community organization will be accomplished only when it is conducted with mixed-species communities.
Collapse
Affiliation(s)
- Paul E Kolenbrander
- Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892-4350, USA.
| | | | | | | | | | | |
Collapse
|
64
|
Takahashi Y, Ruhl S, Yoon JW, Sandberg AL, Cisar JO. Adhesion of viridans group streptococci to sialic acid-, galactose- and N-acetylgalactosamine-containing receptors. ORAL MICROBIOLOGY AND IMMUNOLOGY 2002; 17:257-62. [PMID: 12121477 DOI: 10.1034/j.1399-302x.2002.170409.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The binding of 10 viridans group streptococci to sialic acid-, galactose (Gal)- and N-acetylgalactosamine (GalNAc)-containing receptors was defined by analysis of the interactions between these bacteria and structurally defined glycoconjugates, host cells and other streptococci. All interactions with sialic acid-containing receptors were Ca(2+)-independent as they were not affected by ethyleneglycoltetraacetic acid (EGTA), whereas all interactions with Gal- and GalNAc-containing receptors were Ca(2+)-dependent. Recognition of sialic acid-, Gal- and GalNAc-containing receptors varied widely among the strains examined, in a manner consistent with the association of each of the three lectin-like activities with a different bacterial cell surface component.
Collapse
Affiliation(s)
- Y Takahashi
- Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | | | | | |
Collapse
|
65
|
|
66
|
Takahashi Y, Konishi K, Cisar JO, Yoshikawa M. Identification and characterization of hsa, the gene encoding the sialic acid-binding adhesin of Streptococcus gordonii DL1. Infect Immun 2002; 70:1209-18. [PMID: 11854202 PMCID: PMC127787 DOI: 10.1128/iai.70.3.1209-1218.2002] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Oral colonization by Streptococcus gordonii, an important cause of subacute bacterial endocarditis, involves bacterial recognition of sialic acid-containing host receptors. The sialic acid-binding activity of this microorganism was previously detected by bacterium-mediated hemagglutination and associated with a streptococcal surface component identified as the Hs antigen. The gene for this antigen (hsa) has now been cloned in Escherichia coli, and its expression has been detected by colony immunoblotting with anti-Hs serum. Mutants of S. gordonii containing hsa inactivated by the insertion of an erythromycin resistance gene or deletion from the chromosome were negative for Hs-immunoreactivity, bacterium-mediated hemagglutinating activity, and adhesion to alpha 2-3-linked sialoglycoconjugates. The deletion in the latter mutants was complemented by plasmid-borne hsa, resulting in Hs antigen production and the restoration of cell surface sialic acid-binding activity. The hsa gene encodes a 203-kDa protein with two serine-rich repetitive regions in its 2,178-amino-acid sequence. The first serine-rich region occurs within the amino-terminal region of the molecule, between different nonrepetitive sequences that may be associated with sialic acid binding. The second serine-rich region, which is much longer than the first, is highly repetitive, containing 113 dodecapeptide repeats with a consensus sequence of SASTSASVSASE. This long repetitive region is followed by a typical gram-positive cell wall anchoring region at the carboxyl-terminal end. Thus, the predicted properties of Hsa, which suggest an amino-terminal receptor-binding domain attached to the cell surface by a molecular stalk, are consistent with the identification of this protein as the sialic acid-binding adhesin of S. gordonii DL1.
Collapse
Affiliation(s)
- Yukihiro Takahashi
- Department of Microbiology, The Nippon Dental University School of Dentistry at Tokyo, Chiyoda-ku, Tokyo 102-8159, Japan.
| | | | | | | |
Collapse
|
67
|
Angata T, Varki A. Chemical diversity in the sialic acids and related alpha-keto acids: an evolutionary perspective. Chem Rev 2002; 102:439-69. [PMID: 11841250 DOI: 10.1021/cr000407m] [Citation(s) in RCA: 935] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Takashi Angata
- Glycobiology Research and Training Center, Department of Medicine, University of California-San Diego, La Jolla, California 92093-0687, USA
| | | |
Collapse
|
68
|
Kolenbrander PE, Andersen RN, Kazmerzak K, Wu R, Palmer RJ. Spatial organization of oral bacteria in biofilms. Methods Enzymol 2001; 310:322-32. [PMID: 10547802 DOI: 10.1016/s0076-6879(99)10026-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- P E Kolenbrander
- Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892-4350, USA
| | | | | | | | | |
Collapse
|
69
|
Ruhl S, Cisar JO, Sandberg AL. Identification of polymorphonuclear leukocyte and HL-60 cell receptors for adhesins of Streptococcus gordonii and Actinomyces naeslundii. Infect Immun 2000; 68:6346-54. [PMID: 11035744 PMCID: PMC97718 DOI: 10.1128/iai.68.11.6346-6354.2000] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Interactions of oral streptococci and actinomyces with polymorphonuclear leukocytes (PMNs), mediated by sialic acid- and Gal/GalNAc-reactive adhesins, respectively, result in activation of the PMNs and thereby may contribute to the initiation of oral inflammation. Sialidase treatment of PMNs or HL-60 cells abolished adhesion of Streptococcus gordonii but was required for adhesion of Actinomyces naeslundii. The same effects of sialidase were noted for adhesion of these bacteria to a major 150-kDa surface glycoprotein of either PMNs or undifferentiated HL-60 cells and to a 130-kDa surface glycoprotein of differentiated HL-60 cells. These glycoproteins were both identified as leukosialin (CD43) by immunoprecipitation with a specific monoclonal antibody (MAb). Adhesion of streptococci and actinomyces to a 200-kDa minor PMN surface glycoprotein was also detected by bacterial overlay of untreated and sialidase-treated nitrocellulose transfers, respectively. This glycoprotein was identified as leukocyte common antigen (CD45) by immunoprecipitation with a specific MAb. CD43 and CD45 both possess extracellular mucinlike domains in addition to intracellular domains that are implicated in signal transduction. Consequently, the interactions of streptococci and actinomyces with the mucinlike domains of these mammalian cell surface glycoproteins result not only in adhesion but, in addition, may represent the initial step in PMN activation by these bacteria.
Collapse
Affiliation(s)
- S Ruhl
- Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | |
Collapse
|
70
|
Yeung MK. Molecular and genetic analyses of Actinomyces spp. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 2000; 10:120-38. [PMID: 10759417 DOI: 10.1177/10454411990100020101] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Members of the genus Actinomyces are predominant primary colonizers of the oral cavity and play an important role in initiating plaque development. These bacteria have evolved unique mechanisms that favor colonization and persistence in this micro-environment. The expression of cell-surface fimbriae is correlated with the ability of these bacteria to adhere to specific receptors on the tooth and mucosal surfaces, and to interact with other plaque bacteria. The elaboration of sialidase is thought to enhance fimbriae-mediated adherence by unmasking the fimbrial receptors on mammalian cells. The presence of certain cell-associated or extracellular enzymes, including those involved in sucrose or urea metabolism, may provide the means for these bacteria to thrive under conditions when other growth nutrients are not available. Moreover, these enzyme activities may influence the distribution of other plaque bacteria and promote selection for Actinomyces spp. in certain ecological niches. The recent development of a genetic transfer system for Actinomyces spp. has allowed for studies the results of which demonstrate the existence of multiple genes involved in fimbriae synthesis and function, and facilitated the construction of allelic replacement mutants at each gene locus. Analyses of these mutants have revealed a direct correlation between the synthesis of assembled fimbriae and the observed adherence properties. Further genetic analysis of the various enzyme activities detected from strains of Actinomyces should allow for an assessment of the role of these components in microbial ecology, and their contribution to the overall success of Actinomyces spp. as a primary colonizer and a key player in oral health and disease.
Collapse
Affiliation(s)
- M K Yeung
- Department of Pediatric Dentistry, University of Texas Health Science Center at San Antonio, 78284, USA
| |
Collapse
|