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Puspitasari R, Irnawati D, Widjijono. The effect of zinc oxide (ZnO) nanoparticle concentration on the adhesion of mucin and Streptococcus mutans to heat-cured acrylic resin. Dent Mater J 2023; 42:791-799. [PMID: 37793826 DOI: 10.4012/dmj.2023-016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
Incorporating zinc oxide (ZnO) nanoparticles as antibacterial fillers in heat-cured acrylic resin could decrease mucin and Streptococcus mutans (S. mutans) adhesion, reducing the incidence of dental caries in the baseplates of orthodontic patients. Here, ZnO nanoparticles were modified using 3-(trimethoxysilyl)propyl methacrylate with various concentrations, added to acrylic resin powder, homogenized, mixed with acrylic resin liquid, and processed. The composite systems interfered well with mucin and S. mutans adhesion. The lowest mean of the amount of mucin adhered was on heat-cured acrylic resin with 7.5% ZnO nanoparticles, with a standard deviation of 18.07±0.80 mg/mL. The ZnO nanoparticles with a concentration of 7.5% showed an 87.09±0.88% S. mutans adhesion in control groups with no additives. These composite systems were proven to have better physicochemical characteristics and antibacterial abilities. Combining ZnO nanoparticles with heat-cured acrylic resin has great potential for self-cleaning baseplates of orthodontic patients in the future.
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Affiliation(s)
- Rahmadani Puspitasari
- Magister Dental Science Study Program, Faculty of Dentistry, Universitas Gadjah Mada
| | - Dyah Irnawati
- Department of Dental Biomaterial, Faculty of Dentistry, Universitas Gadjah Mada
| | - Widjijono
- Department of Dental Biomaterial, Faculty of Dentistry, Universitas Gadjah Mada
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2
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Gaytán MO, Singh AK, Woodiga SA, Patel SA, An SS, Vera-Ponce de León A, McGrath S, Miller AR, Bush JM, van der Linden M, Magrini V, Wilson RK, Kitten T, King SJ. A novel sialic acid-binding adhesin present in multiple species contributes to the pathogenesis of Infective endocarditis. PLoS Pathog 2021; 17:e1009222. [PMID: 33465168 PMCID: PMC7846122 DOI: 10.1371/journal.ppat.1009222] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 01/29/2021] [Accepted: 11/30/2020] [Indexed: 02/07/2023] Open
Abstract
Bacterial binding to platelets is a key step in the development of infective endocarditis (IE). Sialic acid, a common terminal carbohydrate on host glycans, is the major receptor for streptococci on platelets. So far, all defined interactions between streptococci and sialic acid on platelets are mediated by serine-rich repeat proteins (SRRPs). However, we identified Streptococcus oralis subsp. oralis IE-isolates that bind sialic acid but lack SRRPs. In addition to binding sialic acid, some SRRP- isolates also bind the cryptic receptor β-1,4-linked galactose through a yet unknown mechanism. Using comparative genomics, we identified a novel sialic acid-binding adhesin, here named AsaA (associated with sialic acid adhesion A), present in IE-isolates lacking SRRPs. We demonstrated that S. oralis subsp. oralis AsaA is required for binding to platelets in a sialic acid-dependent manner. AsaA comprises a non-repeat region (NRR), consisting of a FIVAR/CBM and two Siglec-like and Unique domains, followed by 31 DUF1542 domains. When recombinantly expressed, Siglec-like and Unique domains competitively inhibited binding of S. oralis subsp. oralis and directly interacted with sialic acid on platelets. We further demonstrated that AsaA impacts the pathogenesis of S. oralis subsp. oralis in a rabbit model of IE. Additionally, we found AsaA orthologues in other IE-causing species and demonstrated that the NRR of AsaA from Gemella haemolysans blocked binding of S. oralis subsp. oralis, suggesting that AsaA contributes to the pathogenesis of multiple IE-causing species. Finally, our findings provide evidence that sialic acid is a key factor for bacterial-platelets interactions in a broader range of species than previously appreciated, highlighting its potential as a therapeutic target. Infective endocarditis (IE) is typically a bacterial infection of the heart valves that causes high mortality. Infective endocarditis can affect people with preexisting lesions on their heart valves (Subacute IE). These lesions contain platelets and other host factors to which bacteria can bind. Growth of bacteria and accumulation of host factors results in heart failure. Therefore, the ability of bacteria to bind platelets is key to the development of IE. Here, we identified a novel bacterial protein, AsaA, which helps bacteria bind to platelets and contributes to the development of disease. Although this virulence factor was characterized in Streptococcus oralis, a leading cause of IE, we demonstrated that AsaA is also present in several other IE-causing bacterial species and is likely relevant to their ability to cause disease. We showed that AsaA binds to sialic acid, a terminal sugar present on platelets, thereby demonstrating that sialic acid serves as a receptor for a wider range of IE-causing bacteria than previously appreciated, highlighting its potential as a therapeutic target.
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Affiliation(s)
- Meztlli O. Gaytán
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Anirudh K. Singh
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Shireen A. Woodiga
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Surina A. Patel
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Seon-Sook An
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Arturo Vera-Ponce de León
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, Ohio, United States of America
| | - Sean McGrath
- Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Anthony R. Miller
- Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Jocelyn M. Bush
- Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Mark van der Linden
- Institute of Medical Microbiology, German National Reference Center for Streptococci, University Hospital (RWTH), Aachen, Germany
| | - Vincent Magrini
- Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, United States of America
| | - Richard K. Wilson
- Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, United States of America
| | - Todd Kitten
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Samantha J. King
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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Uncovering Roles of Streptococcus gordonii SrtA-Processed Proteins in the Biofilm Lifestyle. J Bacteriol 2020; 203:JB.00544-20. [PMID: 33106345 DOI: 10.1128/jb.00544-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 10/20/2020] [Indexed: 12/12/2022] Open
Abstract
Streptococcus gordonii is a commensal oral organism. Harmless in the oral cavity, S. gordonii is an opportunistic pathogen. S. gordonii adheres to body surfaces using surface adhesive proteins (adhesins), which are critical to subsequent formation of biofilm communities. As in most Gram-positive bacteria, S. gordonii surface proteins containing the C-terminal LPXTG motif cleavage sequence are processed by sortase A (SrtA) to become covalently attached to the cell wall. To characterize the functional diversity and redundancy in the family of SrtA-processed proteins, an S. gordonii DL1 markerless deletion mutant library was constructed of each of the 26 putative SrtA-processed proteins. Each library member was evaluated for growth in rich medium, biofilm formation on plastic, saliva and salivary fractions, cell surface hydrophobicity (CSH), hemagglutination, and integration into an ex vivo plaque biofilm community. Library members were compared to the non-SrtA-processed adhesins AbpA and AbpB. While no major growth differences in rich medium were observed, many S. gordonii LPXTG/A proteins impacted biofilm formation on one or more of the substrates. Several mutants showed significant differences in hemagglutination, hydrophobicity, or fitness in the ex vivo plaque model. From the identification of redundant and unique functions in these in vitro and ex vivo systems, functional stratification among the LPXTG/A proteins is apparent.IMPORTANCE S. gordonii interactions with its environment depend on the complement of cell wall proteins. A subset of these cell wall proteins requires processing by the enzyme sortase A (SrtA). The identification of SrtA-processed proteins and their functional characterization will help the community to better understand how S. gordonii engages with its surroundings, including other microbes, integrates into the plaque community, adheres to the tooth surface, and hematogenously disseminates to cause blood-borne infections. This study identified 26 putative SrtA-processed proteins through creation of a markerless deletion mutant library. The library was subject to functional screens that were chosen to better understand key aspects of S. gordonii physiology and pathogenesis.
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Park OJ, Kwon Y, Park C, So YJ, Park TH, Jeong S, Im J, Yun CH, Han SH. Streptococcus gordonii: Pathogenesis and Host Response to Its Cell Wall Components. Microorganisms 2020; 8:microorganisms8121852. [PMID: 33255499 PMCID: PMC7761167 DOI: 10.3390/microorganisms8121852] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 11/23/2020] [Accepted: 11/23/2020] [Indexed: 02/08/2023] Open
Abstract
Streptococcus gordonii, a Gram-positive bacterium, is a commensal bacterium that is commonly found in the skin, oral cavity, and intestine. It is also known as an opportunistic pathogen that can cause local or systemic diseases, such as apical periodontitis and infective endocarditis. S. gordonii, an early colonizer, easily attaches to host tissues, including tooth surfaces and heart valves, forming biofilms. S. gordonii penetrates into root canals and blood streams, subsequently interacting with various host immune and non-immune cells. The cell wall components of S. gordonii, which include lipoteichoic acids, lipoproteins, serine-rich repeat adhesins, peptidoglycans, and cell wall proteins, are recognizable by individual host receptors. They are involved in virulence and immunoregulatory processes causing host inflammatory responses. Therefore, S.gordonii cell wall components act as virulence factors that often progressively develop diseases through overwhelming host responses. This review provides an overview of S. gordonii, and how its cell wall components could contribute to the pathogenesis and development of therapeutic strategies.
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Affiliation(s)
- Ok-Jin Park
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Yeongkag Kwon
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Chaeyeon Park
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Yoon Ju So
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Tae Hwan Park
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Sungho Jeong
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Jintaek Im
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Cheol-Heui Yun
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea;
- Institute of Green Bio Science Technology, Seoul National University, Pyeongchang 25354, Korea
| | - Seung Hyun Han
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
- Correspondence: ; Tel.: +82-2-880-2310
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Bowerman KL, Rehman SF, Vaughan A, Lachner N, Budden KF, Kim RY, Wood DLA, Gellatly SL, Shukla SD, Wood LG, Yang IA, Wark PA, Hugenholtz P, Hansbro PM. Disease-associated gut microbiome and metabolome changes in patients with chronic obstructive pulmonary disease. Nat Commun 2020; 11:5886. [PMID: 33208745 PMCID: PMC7676259 DOI: 10.1038/s41467-020-19701-0] [Citation(s) in RCA: 200] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 10/19/2020] [Indexed: 02/07/2023] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is the third commonest cause of death globally, and manifests as a progressive inflammatory lung disease with no curative treatment. The lung microbiome contributes to COPD progression, but the function of the gut microbiome remains unclear. Here we examine the faecal microbiome and metabolome of COPD patients and healthy controls, finding 146 bacterial species differing between the two groups. Several species, including Streptococcus sp000187445, Streptococcus vestibularis and multiple members of the family Lachnospiraceae, also correlate with reduced lung function. Untargeted metabolomics identifies a COPD signature comprising 46% lipid, 20% xenobiotic and 20% amino acid related metabolites. Furthermore, we describe a disease-associated network connecting Streptococcus parasanguinis_B with COPD-associated metabolites, including N-acetylglutamate and its analogue N-carbamoylglutamate. While correlative, our results suggest that the faecal microbiome and metabolome of COPD patients are distinct from those of healthy individuals, and may thus aid in the search for biomarkers for COPD. Chronic obstructive pulmonary disease (COPD) is a progressing disease, with lung but not gut microbiota implicated in its etiology. Here the authors compare the stool from patients with COPD and healthy controls to find specific gut bacteria and metabolites associated with active disease, thereby hinting at a potential role for the gut microbiome in COPD.
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Affiliation(s)
- Kate L Bowerman
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Saima Firdous Rehman
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, and The University of Newcastle, Newcastle, NSW, Australia
| | - Annalicia Vaughan
- Thoracic Research Centre, Faculty of Medicine, The University of Queensland, and Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, QLD, Australia
| | - Nancy Lachner
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Kurtis F Budden
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, and The University of Newcastle, Newcastle, NSW, Australia
| | - Richard Y Kim
- Centre for Inflammation, Centenary Institute & University of Technology Sydney, School of Life Sciences, Faculty of Science, Sydney, NSW, Australia
| | - David L A Wood
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Shaan L Gellatly
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, and The University of Newcastle, Newcastle, NSW, Australia
| | - Shakti D Shukla
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, and The University of Newcastle, Newcastle, NSW, Australia
| | - Lisa G Wood
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, and The University of Newcastle, Newcastle, NSW, Australia
| | - Ian A Yang
- Thoracic Research Centre, Faculty of Medicine, The University of Queensland, and Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, QLD, Australia
| | - Peter A Wark
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, and The University of Newcastle, Newcastle, NSW, Australia
| | - Philip Hugenholtz
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Philip M Hansbro
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, and The University of Newcastle, Newcastle, NSW, Australia. .,Centre for Inflammation, Centenary Institute & University of Technology Sydney, School of Life Sciences, Faculty of Science, Sydney, NSW, Australia.
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6
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Back CR, Higman VA, Le Vay K, Patel VV, Parnell AE, Frankel D, Jenkinson HF, Burston SG, Crump MP, Nobbs AH, Race PR. The streptococcal multidomain fibrillar adhesin CshA has an elongated polymeric architecture. J Biol Chem 2020; 295:6689-6699. [PMID: 32229583 PMCID: PMC7212634 DOI: 10.1074/jbc.ra119.011719] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/26/2020] [Indexed: 11/06/2022] Open
Abstract
The cell surfaces of many bacteria carry filamentous polypeptides termed adhesins that enable binding to both biotic and abiotic surfaces. Surface adherence is facilitated by the exquisite selectivity of the adhesins for their cognate ligands or receptors and is a key step in niche or host colonization and pathogenicity. Streptococcus gordonii is a primary colonizer of the human oral cavity and an opportunistic pathogen, as well as a leading cause of infective endocarditis in humans. The fibrillar adhesin CshA is an important determinant of S. gordonii adherence, forming peritrichous fibrils on its surface that bind host cells and other microorganisms. CshA possesses a distinctive multidomain architecture comprising an N-terminal target-binding region fused to 17 repeat domains (RDs) that are each ∼100 amino acids long. Here, using structural and biophysical methods, we demonstrate that the intact CshA repeat region (CshA_RD1-17, domains 1-17) forms an extended polymeric monomer in solution. We recombinantly produced a subset of CshA RDs and found that they differ in stability and unfolding behavior. The NMR structure of CshA_RD13 revealed a hitherto unreported all β-fold, flanked by disordered interdomain linkers. These findings, in tandem with complementary hydrodynamic studies of CshA_RD1-17, indicate that this polypeptide possesses a highly unusual dynamic transitory structure characterized by alternating regions of order and disorder. This architecture provides flexibility for the adhesive tip of the CshA fibril to maintain bacterial attachment that withstands shear forces within the human host. It may also help mitigate deleterious folding events between neighboring RDs that share significant structural identity without compromising mechanical stability.
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Affiliation(s)
- Catherine R Back
- Bristol Dental School, University of Bristol, Bristol BS1 2LY, United Kingdom
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - Victoria A Higman
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Kristian Le Vay
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- Bristol Centre for Functional Nanomaterials, H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - Viren V Patel
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Alice E Parnell
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - Daniel Frankel
- School of Engineering, Newcastle University, Newcastle-upon-Tyne NE1 7RU, United Kingdom
| | - Howard F Jenkinson
- Bristol Dental School, University of Bristol, Bristol BS1 2LY, United Kingdom
| | - Steven G Burston
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - Matthew P Crump
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Angela H Nobbs
- Bristol Dental School, University of Bristol, Bristol BS1 2LY, United Kingdom
| | - Paul R Race
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
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Veerapandian R, Vediyappan G. Gymnemic Acids Inhibit Adhesive Nanofibrillar Mediated Streptococcus gordonii-Candida albicans Mono-Species and Dual-Species Biofilms. Front Microbiol 2019; 10:2328. [PMID: 31681200 PMCID: PMC6797559 DOI: 10.3389/fmicb.2019.02328] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/24/2019] [Indexed: 12/17/2022] Open
Abstract
Dental caries and periodontitis are the most common oral disease of all age groups, affecting billions of people worldwide. These oral diseases are mostly associated with microbial biofilms in the oral cavity. Streptococcus gordonii, an early tooth colonizing bacterium and Candida albicans, an opportunistic pathogenic fungus, are the two abundant oral microbes that form mixed biofilms with augmented virulence, affecting oral health negatively. Understanding the molecular mechanisms of the pathogen interactions and identifying non-toxic compounds that block the growth of biofilms are important steps in the development of effective therapeutic approaches. In this in vitro study we report the inhibition of mono-species or dual-species biofilms of S. gordonii and C. albicans, and decreased levels of biofilm extracellular DNA (eDNA), when biofilms were grown in the presence of gymnemic acids (GAs), a non-toxic small molecule inhibitor of fungal hyphae. Scanning electron microscopic images of biofilms on saliva-coated hydroxyapatite (sHA) surfaces revealed attachment of S. gordonii cells to C. albicans hyphae and to sHA surfaces via nanofibrils only in the untreated control, but not in the GAs-treated biofilms. Interestingly, C. albicans produced fibrillar adhesive structures from hyphae when grown with S. gordonii as a mixed biofilm; addition of GAs abrogated the nanofibrils and reduced the growth of both hyphae and the biofilm. To our knowledge, this is the first report that C. albicans produces adhesive fibrils from hyphae in response to S. gordonii mixed biofilm growth. Semi-quantitative PCR of selected genes related to biofilms from both microbes showed differential expression in control vs. treated biofilms. Further, GAs inhibited the activity of recombinant S. gordonii glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Taken together, our results suggest that S. gordonii stimulates the expression of adhesive materials in C. albicans by direct interaction and/or signaling, and the adhesive material expression can be inhibited by GAs.
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Affiliation(s)
- Raja Veerapandian
- Division of Biology, Kansas State University, Manhattan, KS, United States
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8
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Transcriptional profiling of coaggregation interactions between Streptococcus gordonii and Veillonella parvula by Dual RNA-Seq. Sci Rep 2019; 9:7664. [PMID: 31113978 PMCID: PMC6529473 DOI: 10.1038/s41598-019-43979-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 04/12/2019] [Indexed: 12/30/2022] Open
Abstract
Many oral bacteria form macroscopic clumps known as coaggregates when mixed with a different species. It is thought that these cell-cell interactions are critical for the formation of mixed-species biofilms such as dental plaque. Here, we assessed the impact of coaggregation between two key initial colonizers of dental plaque, Streptococcus gordonii and Veillonella parvula, on gene expression in each partner. These species were shown to coaggregate in buffer or human saliva. To monitor gene regulation, coaggregates were formed in human saliva and, after 30 minutes, whole-transcriptomes were extracted for sequencing and Dual RNA-Seq analysis. In total, 272 genes were regulated in V. parvula, including 39 genes in oxidoreductase processes. In S. gordonii, there was a high degree of inter-sample variation. Nevertheless, 69 genes were identified as potentially regulated by coaggregation, including two phosphotransferase system transporters and several other genes involved in carbohydrate metabolism. Overall, these data indicate that responses of V. parvula to coaggregation with S. gordonii are dominated by oxidative stress-related processes, whereas S. gordonii responses are more focussed on carbohydrate metabolism. We hypothesize that these responses may reflect changes in the local microenvironment in biofilms when S. gordonii or V. parvula immigrate into the system.
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9
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Xu Z, Coriand L, Loeffler R, Geis-Gerstorfer J, Zhou Y, Scheideler L, Fleischer M, Gehring FK, Rupp F. Saliva-coated titanium biosensor detects specific bacterial adhesion and bactericide caused mass loading upon cell death. Biosens Bioelectron 2019; 129:198-207. [PMID: 30721795 DOI: 10.1016/j.bios.2019.01.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/07/2019] [Accepted: 01/13/2019] [Indexed: 12/11/2022]
Abstract
Bacteria adhering to implanted medical devices can cause invasive microbial infections, of e.g. skin, lung or blood. In dentistry, Streptococcus gordonii is an early oral colonizer initiating dental biofilm formation and also being involved in life-threatening infective endocarditis. To treat oral biofilms, antibacterial mouth rinses are commonly used. Such initial biomaterial-bacteria interactions and the influence of antibacterial treatments are poorly understood and investigated here in situ by quartz crystal microbalance with dissipation monitoring (QCM-D). A saliva-coated titanium (Ti) biosensor is applied to analyze possible specific signal patterns indicating microbial binding mechanisms and bactericide-caused changes in bacterial film rigidity or cell leakage caused by a clinically relevant antibacterial agent (ABA), i.e., a mouth rinse comprising chlorhexidine (CHX) and cetylpyridinium chloride (CPC). Apparent missing mass effects during the formation of microscopically proven dense and vital bacterial films indicate punctual, specific binding of S. gordonii to the saliva-coated biosensor, compared to unspecific adhesion to pure Ti. Coincidentally to ABA-induced killing of surface-adhered bacteria, an increase of adsorbed dissipative mass can be sensed, contrary to the prior mass-loss. This suggests the acoustic sensing of the leakage of cellular content caused by bacterial cell wall rupturing and membrane damage upon the bactericidal attack. The results have significant implications for testing bacterial adhesion mechanisms and cellular integrity during interaction with antibacterial agents.
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Affiliation(s)
- Zeqian Xu
- University Hospital Tübingen, Section Medical Materials Science & Technology, Osianderstr. 2-8, D-72076 Tübingen, Germany; The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan 430079, PR China
| | - Luisa Coriand
- Fraunhofer Institute for Applied Optics and Precision Engineering, Albert-Einstein-Strasse 7, D-07745 Jena, Germany
| | - Ronny Loeffler
- Core Facility LISA(+), Eberhard Karls University Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| | - Juergen Geis-Gerstorfer
- University Hospital Tübingen, Section Medical Materials Science & Technology, Osianderstr. 2-8, D-72076 Tübingen, Germany
| | - Yi Zhou
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan 430079, PR China
| | - Lutz Scheideler
- University Hospital Tübingen, Section Medical Materials Science & Technology, Osianderstr. 2-8, D-72076 Tübingen, Germany
| | - Monika Fleischer
- Core Facility LISA(+), Eberhard Karls University Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| | | | - Frank Rupp
- University Hospital Tübingen, Section Medical Materials Science & Technology, Osianderstr. 2-8, D-72076 Tübingen, Germany.
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10
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Role of Neuraminidase-Producing Bacteria in Exposing Cryptic Carbohydrate Receptors for Streptococcus gordonii Adherence. Infect Immun 2018; 86:IAI.00068-18. [PMID: 29661931 DOI: 10.1128/iai.00068-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/13/2018] [Indexed: 12/11/2022] Open
Abstract
Streptococcus gordonii is an early colonizer of the oral cavity. Although a variety of S. gordonii adherence mechanisms have been described, current dogma is that the major receptor for S. gordonii is sialic acid. However, as many bacterial species in the oral cavity produce neuraminidase that can cleave terminal sialic acid, it is unclear whether S. gordonii relies on sialic acid for adherence to oral surfaces or if this species has developed alternative binding strategies. Previous studies have examined adherence to immobilized glycoconjugates and identified binding to additional glycans, but no prior studies have defined the contribution of these different glycan structures in adherence to oral epithelial cells. We determined that the majority of S. gordonii strains tested did not rely on sialic acid for efficient adherence. In fact, adherence of some strains was significantly increased following neuraminidase treatment. Further investigation of representative strains that do not rely on sialic acid for adherence revealed binding not only to sialic acid via the serine-rich repeat protein GspB but also to β-1,4-linked galactose. Adherence to this carbohydrate occurs via an unknown adhesin distinct from those utilized by Streptococcus oralis and Streptococcus pneumoniae Demonstrating the potential biological relevance of binding to this cryptic receptor, we established that S. oralis increases S. gordonii adherence in a neuraminidase-dependent manner. These data suggest that S. gordonii has evolved to simultaneously utilize both terminal and cryptic receptors in response to the production of neuraminidase by other species in the oral environment.
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11
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Gafri HFS, Mohamed Zuki F, Aroua MK, Hashim NA. Mechanism of bacterial adhesion on ultrafiltration membrane modified by natural antimicrobial polymers (chitosan) and combination with activated carbon (PAC). REV CHEM ENG 2018. [DOI: 10.1515/revce-2017-0006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Abstract
Bacterial adhesion to surfaces is related to several factors, such as surface charge, surface energy, and substrate characteristics (leading to the formation of biofilms). Organisms are dominant in most environmental, industrial, and medical problems and processes that are of interest to microbiologists. Biofilm cells are at least 500 times more resistant to antibacterial agents compared to planktonic cells. The usage of ultrafiltration membranes is fast becoming popular for water treatment. Membrane lifetime and permeate flux are primarily affected by the phenomena of microbial accumulation and fouling at the membrane’s surface. This review intends to understand the mechanism of membrane fouling by bacterial attachment on polymeric ultrafiltration membrane modified by natural antimicrobial polymers (chitosan) combined with powder activated carbon. Also, to guide future research on membrane water treatment processes, adhesion prediction using the extended Derjaguin-Landau-Verwey-Overbeek theory is discussed.
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Affiliation(s)
- Hasan Fouzi S. Gafri
- Department of Chemical Engineering , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Fathiah Mohamed Zuki
- Department of Chemical Engineering , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Mohamed Kheireddine Aroua
- Centre for Carbon Dioxide Capture and Utilization (CCDCU), School of Science and Technology , Sunway University, Bandar Sunway , 47500 Petaling Jaya , Malaysia
- Department of Engineering , Lancaster University , Lancaster, LA1 4YW , UK
| | - Nur Awanis Hashim
- Department of Chemical Engineering , University of Malaya , 50603 Kuala Lumpur , Malaysia
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12
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Novel Two-Component System of Streptococcus sanguinis Affecting Functions Associated with Viability in Saliva and Biofilm Formation. Infect Immun 2018; 86:IAI.00942-17. [PMID: 29339459 DOI: 10.1128/iai.00942-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 01/08/2018] [Indexed: 02/07/2023] Open
Abstract
Streptococcus sanguinis is a pioneer species of teeth and a common opportunistic pathogen of infective endocarditis. In this study, we identified a two-component system, S. sanguinis SptRS (SptRS Ss ), affecting S. sanguinis survival in saliva and biofilm formation. Isogenic mutants of sptRSs (SKsptR) and sptSSs (SKsptS) showed reduced cell counts in ex vivo assays of viability in saliva compared to those of parent strain SK36 and complemented mutants. Reduced counts of the mutants in saliva were associated with reduced growth rates in nutrient-poor medium (RPMI) and increased susceptibility to the deposition of C3b and the membrane attach complex (MAC) of the complement system, a defense component of saliva and serum. Conversely, sptRSs and sptSSs mutants showed increased biofilm formation associated with higher levels of production of H2O2 and extracellular DNA. Reverse transcription-quantitative PCR (RT-qPCR) comparisons of strains indicated a global role of SptRS Ss in repressing genes for H2O2 production (2.5- to 15-fold upregulation of spxB, spxR, vicR, tpk, and ackA in sptRSs and sptSSs mutants), biofilm formation, and/or evasion of host immunity (2.1- to 11.4-fold upregulation of srtA, pcsB, cwdP, iga, and nt5e). Compatible with the homology of SptR Ss with AraC-type regulators, duplicate to multiple conserved repeats were identified in 1,000-bp regulatory regions of downstream genes, suggesting that SptR Ss regulates transcription by DNA looping. Significant transcriptional changes in the regulatory genes vicR, spxR, comE, comX, and mecA in the sptRSs and sptSSs mutants further indicated that SptRS Ss is part of a regulatory network that coordinates cell wall homeostasis, H2O2 production, and competence. This study reveals that SptRS Ss is involved in the regulation of crucial functions for S. sanguinis persistence in the oral cavity.
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13
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Couvigny B, Kulakauskas S, Pons N, Quinquis B, Abraham AL, Meylheuc T, Delorme C, Renault P, Briandet R, Lapaque N, Guédon E. Identification of New Factors Modulating Adhesion Abilities of the Pioneer Commensal Bacterium Streptococcus salivarius. Front Microbiol 2018. [PMID: 29515553 PMCID: PMC5826255 DOI: 10.3389/fmicb.2018.00273] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Biofilm formation is crucial for bacterial community development and host colonization by Streptococcus salivarius, a pioneer colonizer and commensal bacterium of the human gastrointestinal tract. This ability to form biofilms depends on bacterial adhesion to host surfaces, and on the intercellular aggregation contributing to biofilm cohesiveness. Many S. salivarius isolates auto-aggregate, an adhesion process mediated by cell surface proteins. To gain an insight into the genetic factors of S. salivarius that dictate host adhesion and biofilm formation, we developed a screening method, based on the differential sedimentation of bacteria in semi-liquid conditions according to their auto-aggregation capacity, which allowed us to identify twelve mutations affecting this auto-aggregation phenotype. Mutations targeted genes encoding (i) extracellular components, including the CshA surface-exposed protein, the extracellular BglB glucan-binding protein, the GtfE, GtfG and GtfH glycosyltransferases and enzymes responsible for synthesis of cell wall polysaccharides (CwpB, CwpK), (ii) proteins responsible for the extracellular localization of proteins, such as structural components of the accessory SecA2Y2 system (Asp1, Asp2, SecA2) and the SrtA sortase, and (iii) the LiaR transcriptional response regulator. These mutations also influenced biofilm architecture, revealing that similar cell-to-cell interactions govern assembly of auto-aggregates and biofilm formation. We found that BglB, CshA, GtfH and LiaR were specifically associated with bacterial auto-aggregation, whereas Asp1, Asp2, CwpB, CwpK, GtfE, GtfG, SecA2 and SrtA also contributed to adhesion to host cells and host-derived components, or to interactions with the human pathogen Fusobacterium nucleatum. Our study demonstrates that our screening method could also be used to identify genes implicated in the bacterial interactions of pathogens or probiotics, for which aggregation is either a virulence trait or an advantageous feature, respectively.
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Affiliation(s)
- Benoit Couvigny
- MICALIS Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Saulius Kulakauskas
- MICALIS Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Nicolas Pons
- MetaGenoPoliS, INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | - Benoit Quinquis
- MetaGenoPoliS, INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | | | - Thierry Meylheuc
- MICALIS Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France.,INRA, Plateforme MIMA2, Jouy-en-Josas, France
| | - Christine Delorme
- MICALIS Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Pierre Renault
- MICALIS Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Romain Briandet
- MICALIS Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Nicolas Lapaque
- MICALIS Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Eric Guédon
- STLO, UMR 1253, INRA, Agrocampus Ouest, Rennes, France
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14
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Robinson J, Rostami N, Casement J, Vollmer W, Rickard A, Jakubovics N. ArcR modulates biofilm formation in the dental plaque colonizerStreptococcus gordonii. Mol Oral Microbiol 2018; 33:143-154. [DOI: 10.1111/omi.12207] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2017] [Indexed: 01/20/2023]
Affiliation(s)
- J.C. Robinson
- School of Dental Sciences; Newcastle University; Newcastle upon Tyne UK
| | - N. Rostami
- School of Dental Sciences; Newcastle University; Newcastle upon Tyne UK
| | - J. Casement
- Bioinformatics Support Unit; Newcastle University; Newcastle upon Tyne UK
| | - W. Vollmer
- Centre for Bacterial Cell Biology; Newcastle University; Newcastle upon Tyne UK
| | - A.H. Rickard
- Department of Epidemiology; School of Public Health; University of Michigan; Ann Arbor MI USA
| | - N.S. Jakubovics
- School of Dental Sciences; Newcastle University; Newcastle upon Tyne UK
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15
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Back CR, Sztukowska MN, Till M, Lamont RJ, Jenkinson HF, Nobbs AH, Race PR. The Streptococcus gordonii Adhesin CshA Protein Binds Host Fibronectin via a Catch-Clamp Mechanism. J Biol Chem 2017; 292:1538-1549. [PMID: 27920201 PMCID: PMC5290933 DOI: 10.1074/jbc.m116.760975] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 12/01/2016] [Indexed: 11/06/2022] Open
Abstract
Adherence of bacteria to biotic or abiotic surfaces is a prerequisite for host colonization and represents an important step in microbial pathogenicity. This attachment is facilitated by bacterial adhesins at the cell surface. Because of their size and often elaborate multidomain architectures, these polypeptides represent challenging targets for detailed structural and functional characterization. The multifunctional fibrillar adhesin CshA, which mediates binding to both host molecules and other microorganisms, is an important determinant of colonization by Streptococcus gordonii, an oral commensal and opportunistic pathogen of animals and humans. CshA binds the high-molecular-weight glycoprotein fibronectin (Fn) via an N-terminal non-repetitive region, and this protein-protein interaction has been proposed to promote S. gordonii colonization at multiple sites within the host. However, the molecular details of how these two proteins interact have yet to be established. Here we present a structural description of the Fn binding N-terminal region of CshA, derived from a combination of X-ray crystallography, small angle X-ray scattering, and complementary biophysical methods. In vitro binding studies support a previously unreported two-state "catch-clamp" mechanism of Fn binding by CshA, in which the disordered N-terminal domain of CshA acts to "catch" Fn, via formation of a rapidly assembled but also readily dissociable pre-complex, enabling its neighboring ligand binding domain to tightly clamp the two polypeptides together. This study presents a new paradigm for target binding by a bacterial adhesin, the identification of which will inform future efforts toward the development of anti-adhesive agents that target S. gordonii and related streptococci.
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Affiliation(s)
- Catherine R Back
- From the School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, United Kingdom
| | - Maryta N Sztukowska
- the Department of Oral Immunology and Infectious Diseases, University of Louisville, Louisville, Kentucky 40202; the Department of Dentistry, University of Information Technology and Management, 35-225 Rzeszow, Poland
| | - Marisa Till
- the School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom; the BrisSynBio Synthetic Biology Research Centre, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, United Kingdom
| | - Richard J Lamont
- the Department of Oral Immunology and Infectious Diseases, University of Louisville, Louisville, Kentucky 40202
| | - Howard F Jenkinson
- From the School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, United Kingdom
| | - Angela H Nobbs
- From the School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, United Kingdom.
| | - Paul R Race
- the School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom; the BrisSynBio Synthetic Biology Research Centre, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, United Kingdom.
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16
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Haworth JA, Jenkinson HF, Petersen HJ, Back CR, Brittan JL, Kerrigan SW, Nobbs AH. Concerted functions of Streptococcus gordonii surface proteins PadA and Hsa mediate activation of human platelets and interactions with extracellular matrix. Cell Microbiol 2017; 19:e12667. [PMID: 27616700 PMCID: PMC5574023 DOI: 10.1111/cmi.12667] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/23/2016] [Accepted: 09/07/2016] [Indexed: 12/17/2022]
Abstract
A range of Streptococcus bacteria are able to interact with blood platelets to form a thrombus (clot). Streptococcus gordonii is ubiquitous within the human oral cavity and amongst the common pathogens isolated from subjects with infective endocarditis. Two cell surface proteins, Hsa and Platelet adherence protein A (PadA), in S. gordonii mediate adherence and activation of platelets. In this study, we demonstrate that PadA binds activated platelets and that an NGR (Asparagine-Glycine-Arginine) motif within a 657 amino acid residue N-terminal fragment of PadA is responsible for this, together with two other integrin-like recognition motifs RGT and AGD. PadA also acts in concert with Hsa to mediate binding of S. gordonii to cellular fibronectin and vitronectin, and to promote formation of biofilms. Evidence is presented that PadA and Hsa are each reliant on the other's active presentation on the bacterial cell surface, suggesting cooperativity in functions impacting both colonization and pathogenesis.
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Affiliation(s)
| | | | | | | | - Jane L. Brittan
- School of Oral and Dental SciencesUniversity of BristolBristolUK
| | - Steve W. Kerrigan
- Cardiovascular Infection GroupRoyal College of Surgeons in IrelandDublin 2Ireland
| | - Angela H. Nobbs
- School of Oral and Dental SciencesUniversity of BristolBristolUK
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17
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Oguchi R, Takahashi Y, Shimazu K, Urano-Tashiro Y, Kawarai T, Konishi K, Karibe H. Contribution of Streptococcus gordonii Hsa Adhesin to Biofilm Formation. Jpn J Infect Dis 2016; 70:399-404. [PMID: 28003605 DOI: 10.7883/yoken.jjid.2016.492] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Adhesion of oral mitis group streptococci, such as Streptococcus gordonii, to acquired pellicle on the tooth surface is the first step in oral biofilm formation. S. gordonii strain DL1 possesses an Hsa adhesin, which recognizes the terminal sialic acid of host sialoglycoconjugates. The aim of the present study was to investigate the role of the Hsa adhesin in biofilm formation. The biofilm-forming ability of a S. gordonii hsa mutant on microtiter plates pre-coated with saliva, fetuin, or mucin was significantly lower than that of wild-type strain DL1. In contrast, no significant difference in biofilm-forming ability was observed in plates pre-coated with bovine serum albumin, which does not contain sialic acid. The biofilm-forming ability of strain DL1 in saliva-coated microtiter plates was also significantly reduced when the plate was pre-treated with neuraminidase. The sialic acid-dependent biofilm-forming ability of different wild-type S. gordonii strains varied. However, Southern and western blot analyses showed that all the tested wild-type strains possessed and expressed hsa homologs, respectively. These results indicate that the binding of Hsa adhesin to sialoglycoconjugates is associated with biofilm formation of S. gordonii DL1, and imply variation in the contribution of Hsa and its homologs to S. gordonii biofilm formation.
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Affiliation(s)
- Riyo Oguchi
- Department of Pediatric Dentistry, The Nippon Dental University School of Life Dentistry at Tokyo.,Department of Microbiology, The Nippon Dental University School of Life Dentistry at Tokyo
| | - Yukihiro Takahashi
- Department of Microbiology, The Nippon Dental University School of Life Dentistry at Tokyo
| | - Kisaki Shimazu
- Department of Pediatric Dentistry, The Nippon Dental University School of Life Dentistry at Tokyo
| | - Yumiko Urano-Tashiro
- Department of Microbiology, The Nippon Dental University School of Life Dentistry at Tokyo
| | - Taketo Kawarai
- Department of Microbiology, The Nippon Dental University School of Life Dentistry at Tokyo
| | - Kiyoshi Konishi
- Department of Microbiology, The Nippon Dental University School of Life Dentistry at Tokyo
| | - Hiroyuki Karibe
- Department of Pediatric Dentistry, The Nippon Dental University School of Life Dentistry at Tokyo
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18
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The Sialic Acid Binding Protein, Hsa, in Streptococcus gordonii DL1 also Mediates Intergeneric Coaggregation with Veillonella Species. PLoS One 2015; 10:e0143898. [PMID: 26606595 PMCID: PMC4659562 DOI: 10.1371/journal.pone.0143898] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 11/10/2015] [Indexed: 12/28/2022] Open
Abstract
Dental biofilm development involves initial colonization of the tooth’s surface by pioneer colonizers, followed by cell-cell coaggregation between the pioneer and later colonizers. Streptococcus gordonii is one of the pioneer colonizers. In addition to its role in oral biofilm development, S. gordonii also is a pathogen in infective endocarditis in susceptible humans. A surface adhesin, Hsa, has been shown to play a critical role in colonization of S. gordonii on the heart tissue; however, its role in oral biofilm development has not been reported. In this study we demonstrate that Hsa is essential for coaggregation between S. gordonii and Veillonella sp., which are bridging species connecting the pioneer colonizers to the late colonizers. Interestingly, the same domains shown to be required for Hsa binding to sialic acid on the human cell surface are also required for coaggregation with Veillonella sp. However, sialic acid appeared not to be required for this intergeneric coaggregation. This result suggests that although the same domains of Hsa are involved in binding to eukaryotic as well as Veillonella cells, the binding mechanism is different. The gene expression pattern of hsa was also studied and shown not to be induced by coaggregation with Veillonella sp.
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19
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Xu H, Jenkinson HF, Dongari-Bagtzoglou A. Innocent until proven guilty: mechanisms and roles of Streptococcus-Candida interactions in oral health and disease. Mol Oral Microbiol 2015; 29:99-116. [PMID: 24877244 PMCID: PMC4238848 DOI: 10.1111/omi.12049] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Candida albicans and streptococci of the mitis group colonize the oral cavities of the majority of healthy humans. While C. albicans is considered an opportunistic pathogen, streptococci of this group are broadly considered avirulent or even beneficial organisms. However, recent evidence suggests that multi-species biofilms with these organisms may play detrimental roles in host homeostasis and may promote infection. In this review we summarize the literature on molecular interactions between members of this streptococcal group and C. albicans, with emphasis on their potential role in the pathogenesis of opportunistic oral mucosal infections.
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20
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Generic determinants of Streptococcus colonization and infection. INFECTION GENETICS AND EVOLUTION 2015; 33:361-70. [DOI: 10.1016/j.meegid.2014.09.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 09/10/2014] [Accepted: 09/14/2014] [Indexed: 11/20/2022]
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21
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Krasowska A, Sigler K. How microorganisms use hydrophobicity and what does this mean for human needs? Front Cell Infect Microbiol 2014; 4:112. [PMID: 25191645 PMCID: PMC4137226 DOI: 10.3389/fcimb.2014.00112] [Citation(s) in RCA: 329] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 07/29/2014] [Indexed: 11/25/2022] Open
Abstract
Cell surface hydrophobicity (CSH) plays a crucial role in the attachment to, or detachment from the surfaces. The influence of CSH on adhesion of microorganisms to biotic and abiotic surfaces in medicine as well as in bioremediation and fermentation industry has both negative and positive aspects. Hydrophobic microorganisms cause the damage of surfaces by biofilm formation; on the other hand, they can readily accumulate on organic pollutants and decompose them. Hydrophilic microorganisms also play a considerable role in removing organic wastes from the environment because of their high resistance to hydrophobic chemicals. Despite the many studies on the environmental and metabolic factors affecting CSH, the knowledge of this subject is still scanty and is in most cases limited to observing the impact of hydrophobicity on adhesion, aggregation or flocculation. The future of research seems to lie in finding a way to managing the microbial adhesion process, perhaps by steering cell hydrophobicity.
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Affiliation(s)
- Anna Krasowska
- Department of Biotransformation, Faculty of Biotechnology, University of Wroclaw Wroclaw, Poland
| | - Karel Sigler
- Department of Cell Biology, Institute of Microbiology, Czech Academy of Sciences Prague, Czech Republic
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22
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Krajewski S, Rheinlaender J, Ries P, Canjuga D, Mack C, Scheideler L, Schäffer TE, Geis-Gerstorfer J, Wendel HP, Rupp F. Bacterial interactions with proteins and cells relevant to the development of life-threatening endocarditis studied by use of a quartz-crystal microbalance. Anal Bioanal Chem 2014; 406:3395-406. [DOI: 10.1007/s00216-014-7769-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/12/2014] [Accepted: 03/16/2014] [Indexed: 12/17/2022]
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23
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El-Kirat-Chatel S, Beaussart A, Boyd CD, O’Toole GA, Dufrêne YF. Single-cell and single-molecule analysis deciphers the localization, adhesion, and mechanics of the biofilm adhesin LapA. ACS Chem Biol 2014; 9:485-94. [PMID: 24556201 DOI: 10.1021/cb400794e] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The large adhesin protein LapA mediates adhesion and biofilm formation by Pseudomonas fluorescens. Although adhesion is thought to involve the long multiple repeats of LapA, very little is known about the molecular mechanism by which this protein mediates attachment. Here we use atomic force microscopy to unravel the biophysical properties driving LapA-mediated adhesion. Single-cell force spectroscopy shows that expression of LapA on the cell surface via biofilm-inducing conditions (i.e., phosphate-rich medium) or deletion of the gene encoding the LapG protease (LapA+ mutant) increases the adhesion strength of P. fluorescens toward hydrophobic and hydrophilic substrates, consistent with the adherent phenotypes observed in these conditions. Substrate chemistry plays an unexpected role in modulating the mechanical response of LapA, with sequential unfolding of the multiple repeats occurring only on hydrophilic substrates. Biofilm induction also leads to shortening of the protein extensions, reflecting stiffening of their conformational properties. Using single-molecule force spectroscopy, we next demonstrate that the adhesin is randomly distributed on the surface of wild-type cells and can be released into the solution. For LapA+ mutant cells, we found that the adhesin massively accumulates on the cell surface without being released and that individual LapA repeats unfold when subjected to force. The remarkable adhesive and mechanical properties of LapA provide a molecular basis for the "multi-purpose" adhesion function of LapA, thereby making P. fluorescens capable of colonizing diverse environments.
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Affiliation(s)
- Sofiane El-Kirat-Chatel
- Institute
of Life Sciences, Université catholique de Louvain, Croix du
Sud, 1, bte L7.04.01, B-1348 Louvain-la-Neuve, Belgium
| | - Audrey Beaussart
- Institute
of Life Sciences, Université catholique de Louvain, Croix du
Sud, 1, bte L7.04.01, B-1348 Louvain-la-Neuve, Belgium
| | - Chelsea D. Boyd
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
| | - George A. O’Toole
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
| | - Yves F. Dufrêne
- Institute
of Life Sciences, Université catholique de Louvain, Croix du
Sud, 1, bte L7.04.01, B-1348 Louvain-la-Neuve, Belgium
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24
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Sullan RMA, Beaussart A, Tripathi P, Derclaye S, El-Kirat-Chatel S, Li JK, Schneider YJ, Vanderleyden J, Lebeer S, Dufrêne YF. Single-cell force spectroscopy of pili-mediated adhesion. NANOSCALE 2014; 6:1134-1143. [PMID: 24296882 DOI: 10.1039/c3nr05462d] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Although bacterial pili are known to mediate cell adhesion to a variety of substrates, the molecular interactions behind this process are poorly understood. We report the direct measurement of the forces guiding pili-mediated adhesion, focusing on the medically important probiotic bacterium Lactobacillus rhamnosus GG (LGG). Using non-invasive single-cell force spectroscopy (SCFS), we quantify the adhesion forces between individual bacteria and biotic (mucin, intestinal cells) or abiotic (hydrophobic monolayers) surfaces. On hydrophobic surfaces, bacterial pili strengthen adhesion through remarkable nanospring properties, which - presumably - enable the bacteria to resist high shear forces under physiological conditions. On mucin, nanosprings are more frequent and adhesion forces larger, reflecting the influence of specific pili-mucin bonds. Interestingly, these mechanical responses are no longer observed on human intestinal Caco-2 cells. Rather, force curves exhibit constant force plateaus with extended ruptures reflecting the extraction of membrane nanotethers. These single-cell analyses provide novel insights into the molecular mechanisms by which piliated bacteria colonize surfaces (nanosprings, nanotethers), and offer exciting avenues in nanomedicine for understanding and controlling the adhesion of microbial cells (probiotics, pathogens).
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Affiliation(s)
- Ruby May A Sullan
- Université catholique de Louvain, Institute of Life Sciences, Croix du Sud, 1, bte L7.04.01., B-1348 Louvain-la-Neuve, Belgium.
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Jakubovics NS, Yassin SA, Rickard AH. Community interactions of oral streptococci. ADVANCES IN APPLIED MICROBIOLOGY 2014; 87:43-110. [PMID: 24581389 DOI: 10.1016/b978-0-12-800261-2.00002-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
It is now clear that the most common oral diseases, dental caries and periodontitis, are caused by mixed-species communities rather than by individual pathogens working in isolation. Oral streptococci are central to these disease processes since they are frequently the first microorganisms to colonize oral surfaces and they are numerically the dominant microorganisms in the human mouth. Numerous interactions between oral streptococci and other bacteria have been documented. These are thought to be critical for the development of mixed-species oral microbial communities and for the transition from oral health to disease. Recent metagenomic studies are beginning to shed light on the co-occurrence patterns of streptococci with other oral bacteria. Refinements in microscopy techniques and biofilm models are providing detailed insights into the spatial distribution of streptococci in oral biofilms. Targeted genetic manipulation is increasingly being applied for the analysis of specific genes and networks that modulate interspecies interactions. From this work, it is clear that streptococci produce a range of extracellular factors that promote their integration into mixed-species communities and enable them to form social networks with neighboring taxa. These "community integration factors" include coaggregation-mediating adhesins and receptors, small signaling molecules such as peptides or autoinducer-2, bacteriocins, by-products of metabolism including hydrogen peroxide and lactic acid, and a range of extracellular enzymes. Here, we provide an overview of various types of community interactions between oral streptococci and other microorganisms, and we consider the possibilities for the development of new technologies to interfere with these interactions to help control oral biofilms.
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Affiliation(s)
- Nicholas S Jakubovics
- Oral Biology, School of Dental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.
| | - Sufian A Yassin
- Oral Biology, School of Dental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Alexander H Rickard
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA
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Schweikl H, Hiller KA, Carl U, Schweiger R, Eidt A, Ruhl S, Müller R, Schmalz G. Salivary protein adsorption and Streptococccus gordonii adhesion to dental material surfaces. Dent Mater 2013; 29:1080-9. [DOI: 10.1016/j.dental.2013.07.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 07/25/2013] [Accepted: 07/25/2013] [Indexed: 11/17/2022]
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Nylander Å, Svensäter G, Senadheera DB, Cvitkovitch DG, Davies JR, Persson K. Structural and functional analysis of the N-terminal domain of the Streptococcus gordonii adhesin Sgo0707. PLoS One 2013; 8:e63768. [PMID: 23691093 PMCID: PMC3656908 DOI: 10.1371/journal.pone.0063768] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 04/05/2013] [Indexed: 12/02/2022] Open
Abstract
The commensal Streptococcus gordonii expresses numerous surface adhesins with which it interacts with other microorganisms, host cells and salivary proteins to initiate dental plaque formation. However, this Gram-positive bacterium can also spread to non-oral sites such as the heart valves and cause infective endocarditis. One of its surface adhesins, Sgo0707, is a large protein composed of a non-repetitive N-terminal region followed by several C-terminal repeat domains and a cell wall sorting motif. Here we present the crystal structure of the Sgo0707 N-terminal domains, refined to 2.1 Å resolution. The model consists of two domains, N1 and N2. The largest domain, N1, comprises a putative binding cleft with a single cysteine located in its centre and exhibits an unexpected structural similarity to the variable domains of the streptococcal Antigen I/II adhesins. The N2-domain has an IgG-like fold commonly found among Gram-positive surface adhesins. Binding studies performed on S. gordonii wild-type and a Sgo0707 deficient mutant show that the Sgo0707 adhesin is involved in binding to type-1 collagen and to oral keratinocytes.
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Affiliation(s)
- Åsa Nylander
- Department of Odontology, Division of Oral Microbiology, Umeå University, Umeå, Sweden
| | - Gunnel Svensäter
- Department of Oral Biology, Faculty of Odontology, Malmö University, Malmö, Sweden
| | | | | | - Julia R. Davies
- Department of Oral Biology, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Karina Persson
- Department of Chemistry, Umeå University, Umeå, Sweden
- * E-mail:
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Wright CJ, Burns LH, Jack AA, Back CR, Dutton LC, Nobbs AH, Lamont RJ, Jenkinson HF. Microbial interactions in building of communities. Mol Oral Microbiol 2013; 28:83-101. [PMID: 23253299 PMCID: PMC3600090 DOI: 10.1111/omi.12012] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2012] [Indexed: 12/31/2022]
Abstract
Establishment of a community is considered to be essential for microbial growth and survival in the human oral cavity. Biofilm communities have increased resilience to physical forces, antimicrobial agents and nutritional variations. Specific cell-to-cell adherence processes, mediated by adhesin-receptor pairings on respective microbial surfaces, are able to direct community development. These interactions co-localize species in mutually beneficial relationships, such as streptococci, veillonellae, Porphyromonas gingivalis and Candida albicans. In transition from the planktonic mode of growth to a biofilm community, microorganisms undergo major transcriptional and proteomic changes. These occur in response to sensing of diffusible signals, such as autoinducer molecules, and to contact with host tissues or other microbial cells. Underpinning many of these processes are intracellular phosphorylation events that regulate a large number of microbial interactions relevant to community formation and development.
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Affiliation(s)
- Christopher J. Wright
- Department of Oral Health and Systemic Disease, University of Louisville, 570 South Preston Street, Louisville, Kentucky, 40202, USA
| | - Logan H. Burns
- Department of Oral Health and Systemic Disease, University of Louisville, 570 South Preston Street, Louisville, Kentucky, 40202, USA
| | - Alison A. Jack
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS12LY, UK
| | - Catherine R. Back
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS12LY, UK
| | - Lindsay C. Dutton
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS12LY, UK
| | - Angela H. Nobbs
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS12LY, UK
| | - Richard J. Lamont
- Department of Oral Health and Systemic Disease, University of Louisville, 570 South Preston Street, Louisville, Kentucky, 40202, USA
| | - Howard F. Jenkinson
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS12LY, UK
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Mullany P, Williams R, Langridge GC, Turner DJ, Whalan R, Clayton C, Lawley T, Hussain H, McCurrie K, Morden N, Allan E, Roberts AP. Behavior and target site selection of conjugative transposon Tn916 in two different strains of toxigenic Clostridium difficile. Appl Environ Microbiol 2012; 78:2147-53. [PMID: 22267673 PMCID: PMC3302608 DOI: 10.1128/aem.06193-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 01/12/2012] [Indexed: 11/20/2022] Open
Abstract
The insertion sites of the conjugative transposon Tn916 in the anaerobic pathogen Clostridium difficile were determined using Illumina Solexa high-throughput DNA sequencing of Tn916 insertion libraries in two different clinical isolates: 630ΔE, an erythromycin-sensitive derivative of 630 (ribotype 012), and the ribotype 027 isolate R20291, which was responsible for a severe outbreak of C. difficile disease. A consensus 15-bp Tn916 insertion sequence was identified which was similar in both strains, although an extended consensus sequence was observed in R20291. A search of the C. difficile 630 genome showed that the Tn916 insertion motif was present 100,987 times, with approximately 63,000 of these motifs located in genes and 35,000 in intergenic regions. To test the usefulness of Tn916 as a mutagen, a functional screen allowed the isolation of a mutant. This mutant contained Tn916 inserted into a gene involved in flagellar biosynthesis.
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Affiliation(s)
- Peter Mullany
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College London, London, UK.
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Rukke HV, Hegna IK, Petersen FC. Identification of a functional capsule locus in Streptococcus mitis. Mol Oral Microbiol 2011; 27:95-108. [PMID: 22394468 DOI: 10.1111/j.2041-1014.2011.00635.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The polysaccharide capsule of Streptococcus pneumoniae is a hallmark for virulence in humans. In its close relative Streptococcus mitis, a common human commensal, analysis of the sequenced genomes of six strains revealed the presence of a putative capsule locus in four of them. We constructed an isogenic S. mitis mutant from the type strain that lacked the 19 open reading frames in the capsule locus (Δcps mutant), using a deletion strategy similar to previous capsule functional studies in S. pneumoniae. Transmission electron microscopy and atomic force microscopy revealed a capsule-like structure in the S. mitis type strain that was absent or reduced in the Δcps mutant. Since S. mitis are predominant oral colonizers of tooth surfaces, we addressed the relevance of the capsule locus for the S. mitis overall surface properties, autoaggregation and biofilm formation. The capsule deletion resulted in a mutant with approximately two-fold increase in hydrophobicity. Binding to the Stains-all cationic dye was reduced by 40%, suggesting a reduction in the overall negative surface charge of the mutant. The mutant exhibited also increased autoaggregation in coaggregation buffer, and up to six-fold increase in biofilm levels. The results suggested that the capsule locus is associated with production of a capsule-like structure in S. mitis and indicated that the S. mitis capsule-like structure may confer surface attributes similar to those associated with the capsule in S. pneumoniae.
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Affiliation(s)
- H V Rukke
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway.
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Kitada K, Oho T. Effect of saliva viscosity on the co-aggregation between oral streptococci and Actinomyces naeslundii. Gerodontology 2011; 29:e981-7. [PMID: 22077758 DOI: 10.1111/j.1741-2358.2011.00595.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND The co-aggregation of oral bacteria leads to their clearance from the oral cavity. Poor oral hygiene and high saliva viscosity are common amongst the elderly; thus, they frequently suffer from pneumonia caused by the aspiration of oral microorganisms. OBJECTIVES To examine the direct effect of saliva viscosity on the co-aggregation of oral streptococci with actinomyces. MATERIALS AND METHODS Fifteen oral streptococcal and a single actinomyces strain were used. Co-aggregation was assessed by a visual assay in phosphate buffer and a spectrophotometric assay in the same buffer containing 0-60% glycerol or whole saliva. RESULTS Nine oral streptococci co-aggregated with Actinomyces naeslundii ATCC12104 in the visual assay and were subsequently used for the spectrophotometric analysis. All tested strains displayed a decrease in co-aggregation with increasing amounts of glycerol in the buffer. The co-aggregation of Streptococcus oralis with A. naeslundii recovered to baseline level following the removal of glycerol. The per cent co-aggregation of S. oralis with A. naeslundii was significantly correlated with the viscosity in unstimulated and stimulated whole saliva samples (correlation coefficients: -0.52 and -0.48, respectively). CONCLUSION This study suggests that saliva viscosity affects the co-aggregation of oral streptococci with actinomyces and that bacterial co-aggregation decreases with increasing saliva viscosity.
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Affiliation(s)
- Katsuhiro Kitada
- Department of Preventive Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, Sakuragaoka, Kagoshima, Japan
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King NP, Beatson SA, Totsika M, Ulett GC, Alm RA, Manning PA, Schembri MA. UafB is a serine-rich repeat adhesin of Staphylococcus saprophyticus that mediates binding to fibronectin, fibrinogen and human uroepithelial cells. MICROBIOLOGY-SGM 2011; 157:1161-1175. [PMID: 21252279 DOI: 10.1099/mic.0.047639-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Staphylococcus saprophyticus is an important cause of urinary tract infection (UTI), particularly among young women, and is second only to uropathogenic Escherichia coli as the most frequent cause of UTI. The molecular mechanisms of urinary tract colonization by S. saprophyticus remain poorly understood. We have identified a novel 6.84 kb plasmid-located adhesin-encoding gene in S. saprophyticus strain MS1146 which we have termed uro-adherence factor B (uafB). UafB is a glycosylated serine-rich repeat protein that is expressed on the surface of S. saprophyticus MS1146. UafB also functions as a major cell surface hydrophobicity factor. To characterize the role of UafB we generated an isogenic uafB mutant in S. saprophyticus MS1146 by interruption with a group II intron. The uafB mutant had a significantly reduced ability to bind to fibronectin and fibrinogen. Furthermore, we show that a recombinant protein containing the putative binding domain of UafB binds specifically to fibronectin and fibrinogen. UafB was not involved in adhesion in a mouse model of UTI; however, we observed a striking UafB-mediated adhesion phenotype to human uroepithelial cells. We have also identified genes homologous to uafB in other staphylococci which, like uafB, appear to be located on transposable elements. Thus, our data indicate that UafB is a novel adhesin of S. saprophyticus that contributes to cell surface hydrophobicity, mediates adhesion to fibronectin and fibrinogen, and exhibits tropism for human uroepithelial cells.
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Affiliation(s)
- Nathan P King
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Scott A Beatson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Makrina Totsika
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Glen C Ulett
- School of Medical Sciences, Centre for Medicine and Oral Health, Griffith University Gold Coast Campus, QLD 4222, Australia
| | | | | | - Mark A Schembri
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
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EM reconstruction of adhesins: future prospects. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 715:271-84. [PMID: 21557070 DOI: 10.1007/978-94-007-0940-9_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Both Gram-negative and Gram-positive pathogenic bacteria present a remarkable number of surface-exposed organelles and secreted toxins that allow them to control the primary stages of infection, bacterial attachment to host cell receptors and colonization. The mediators of these processes, called adhesins, form a heterogeneous group that varies in architecture, domain content and mechanism of binding. A full understanding of how adhesins mediate cellular adhesion and colonization requires quantitative functional assays to evaluate the strength of the binding interactions, as well as determination of the high-resolution three-dimensional structures of the molecules to provide the atomic details of the interactions. The combination of classical imaging techniques like X-ray crystallography and Nuclear Magnetic Resonance (NMR) with the emerging technique of single-particle electron cryomicroscopy has become a tremendously helpful tool to understand the three-dimensional structure at near atomic-level resolution of newly discovered adhesins and their complexes. A detailed study of the structure of these molecules, both isolated and expressed on bacterial surface is a fundamental requirement for understanding the adhesion mechanism to host cells. This chapter will focus on the structure determination of such surface-exposed protein structures in both Gram-negative and Gram-positive bacterial adhesins.
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Interaction of Candida albicans cell wall Als3 protein with Streptococcus gordonii SspB adhesin promotes development of mixed-species communities. Infect Immun 2010; 78:4644-52. [PMID: 20805332 DOI: 10.1128/iai.00685-10] [Citation(s) in RCA: 169] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Candida albicans colonizes human mucosa and prosthetic surfaces associated with artificial joints, catheters, and dentures. In the oral cavity, C. albicans coexists with numerous bacterial species, and evidence suggests that bacteria may modulate fungal growth and biofilm formation. Streptococcus gordonii is found on most oral cavity surfaces and interacts with C. albicans to promote hyphal and biofilm formation. In this study, we investigated the role of the hyphal-wall protein Als3p in interactions of C. albicans with S. gordonii. Utilizing an ALS3 deletion mutant strain, it was shown that cells were not affected in initial adherence to the salivary pellicle or in hyphal formation in the planktonic phase. However, the Als3(-) mutant was unable to form biofilms on the salivary pellicle or deposited S. gordonii DL1 wild-type cells, and after initial adherence, als3Δ/als3Δ (ΔALS3) cells became detached concomitant with hyphal formation. In coaggregation assays, S. gordonii cells attached to, and accumulated around, hyphae formed by C. albicans wild-type cells. However, streptococci failed to attach to hyphae produced by the ΔALS3 mutant. Saccharomyces cerevisiae S150-2B cells expressing Als3p, but not control cells, supported binding of S. gordonii DL1. However, S. gordonii Δ(sspA sspB) cells deficient in production of the surface protein adhesins SspA and SspB showed >50% reduced levels of binding to S. cerevisiae expressing Als3p. Lactococcus lactis cells expressing SspB bound avidly to S. cerevisiae expressing Als3p, but not to S150-2B wild-type cells. These results show that recognition of C. albicans by S. gordonii involves Als3 protein-SspB protein interaction, defining a novel mechanism in fungal-bacterial communication.
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Heterologous expression of Candida albicans cell wall-associated adhesins in Saccharomyces cerevisiae Reveals differential specificities in adherence and biofilm formation and in binding oral Streptococcus gordonii. EUKARYOTIC CELL 2010; 9:1622-34. [PMID: 20709785 DOI: 10.1128/ec.00103-10] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Colonization and infection of the human host by opportunistic pathogen Candida albicans derive from an ability of this fungus to colonize mucosal tissues and prosthetic devices within the polymicrobial communities present. To determine the functions of C. albicans cell wall proteins in interactions with host or bacterial molecules, Saccharomyces cerevisiae was utilized as a surrogate host to express C. albicans cell wall proteins Als3p, Eap1p, Hwp1p, and Rbt1p. Salivary pellicle and fibrinogen were identified as novel substrata for Als3p and Hwp1p, while only Als3p mediated adherence of S. cerevisiae to basement membrane collagen type IV. Parental S. cerevisiae cells failed to form biofilms on salivary pellicle, polystyrene, or silicone, but cells expressing Als3p or Hwp1p exhibited significant attachment to each surface. Virulence factor Rbt1p also conferred lower-level binding to salivary pellicle and polystyrene. S. cerevisiae cells expressing Eap1p formed robust biofilms upon polystyrene surfaces but not salivary pellicle. Proteins Als3p and Eap1p, and to a lesser degree Hwp1p, conferred upon S. cerevisiae the ability to bind cells of the oral primary colonizing bacterium Streptococcus gordonii. These interactions, which occurred independently of amyloid aggregate formation, provide the first examples of specific C. albicans surface proteins serving as receptors for bacterial adhesins. Streptococcus gordonii did not bind parental S. cerevisiae or cells expressing Rbt1p. Taken collectively, these data suggest that a network of cell wall proteins comprising Als3p, Hwp1p, and Eap1p, with complementary adhesive functions, promotes interactions of C. albicans with host and bacterial molecules, thus leading to effective colonization within polymicrobial communities.
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Soriani M, Telford JL. Relevance of pili in pathogenic streptococci pathogenesis and vaccine development. Future Microbiol 2010; 5:735-47. [PMID: 20441546 DOI: 10.2217/fmb.10.37] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A common mechanism used by bacteria to initiate adhesion to host tissues during colonization is the expression of long filamentous structures extending from their surface. These structures, known as pili or fimbriae, were initially identified in Gram-negative bacteria, and are typically formed by noncovalent interactions between pilin subunits. Pili have only recently been described in Gram-positive bacteria. In particular, in pathogenic streptococci the proteinaceous components of pili are covalently polymerized by the action of sortase enzymes similar to those involved in the covalent attachment of Gram-positive surface proteins to the peptidoglycan cell wall. With great relevance to the development of strategies to combat Gram-positive-associated infections, pilus components from pathogenic streptococci have been shown to induce protective immunity in mouse models of streptococcal disease. In addition, recent papers have created new perspectives on the role of such organelles in streptococcal pathogenesis, from the involvement in colonization and biofilm formation to translocation of tissue barriers. All this information makes the characterization of pili a hot scientific issue that we believe will lead to important future developments in understanding bacterial dynamics that lead to successful occupation of microbial niches.
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Affiliation(s)
- Marco Soriani
- Microbial Molecular Biology Department, Novartis Vaccines, Via Fiorentina 1, 53100 Siena, Italy
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37
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Okahashi N, Nakata M, Sakurai A, Terao Y, Hoshino T, Yamaguchi M, Isoda R, Sumitomo T, Nakano K, Kawabata S, Ooshima T. Pili of oral Streptococcus sanguinis bind to fibronectin and contribute to cell adhesion. Biochem Biophys Res Commun 2009; 391:1192-6. [PMID: 20004645 DOI: 10.1016/j.bbrc.2009.12.029] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 12/05/2009] [Indexed: 12/26/2022]
Abstract
Streptococcus sanguinis is a predominant bacterium in the human oral cavity and occasionally causes infective endocarditis. We identified a unique cell surface polymeric structure named pili in this species and investigated its functions in regard to its potential virulence. Pili of S. sanguinis strain SK36 were shown to be composed of three distinctive pilus proteins (PilA, PilB, and PilC), and a pili-deficient mutant demonstrated reduced bacterial adherence to HeLa and human oral epithelial cells. PilC showed a binding ability to fibronectin, suggesting that pili are involved in colonization by this species. In addition, ATCC10556, a standard S. sanguinis strain, was unable to produce pili due to defective pilus genes, which indicates a diversity of pilus expression among various S. sanguinis strains.
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Affiliation(s)
- Nobuo Okahashi
- Department of Oral Frontier Biology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita-Osaka 565-0871, Japan.
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The terminal A domain of the fibrillar accumulation-associated protein (Aap) of Staphylococcus epidermidis mediates adhesion to human corneocytes. J Bacteriol 2009; 191:7007-16. [PMID: 19749046 DOI: 10.1128/jb.00764-09] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The opportunistic pathogen Staphylococcus epidermidis colonizes indwelling medical devices by biofilm formation but is primarily a skin resident. In many S. epidermidis strains biofilm formation is mediated by a cell wall-anchored protein, the accumulation-associated protein (Aap). Here, we investigate the role of Aap in skin adhesion. Aap is an LPXTG protein with a domain architecture including a terminal A domain and a B-repeat region. S. epidermidis NCTC 11047 expresses Aap as localized, lateral tufts of fibrils on one subpopulation of cells (Fib(+)), whereas a second subpopulation does not express these fibrils of Aap (Fib(-)). Flow cytometry showed that 72% of NCTC 11047 cells expressed Aap and that 28% of cells did not. Aap is involved in the adhesion of Fib(+) cells to squamous epithelial cells from the hand (corneocytes), as the recombinant A-domain protein partially blocked binding to corneocytes. To confirm the role of the Aap A domain in corneocyte attachment, Aap was expressed on the surface of Lactococcus lactis MG1363 as sparsely distributed, peritrichous fibrils. The expression of Aap increased corneocyte adhesion 20-fold compared to L. lactis carrying Aap without an A domain. S. epidermidis isolates from catheters, artificial joints, skin, and the nose also used the A domain of Aap to adhere to corneocytes, emphasizing the role of Aap in skin adhesion. In addition, L. lactis expressing Aap with different numbers of B repeats revealed a positive correlation between the number of B repeats and adhesion to corneocytes, suggesting an additional function for the B region in enhancing A-domain-dependent attachment to skin. Therefore, in addition to its established role in biofilm formation, Aap can also promote adhesion to corneocytes and is likely to be an important adhesin in S. epidermidis skin colonization.
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Nobbs AH, Lamont RJ, Jenkinson HF. Streptococcus adherence and colonization. Microbiol Mol Biol Rev 2009; 73:407-50, Table of Contents. [PMID: 19721085 PMCID: PMC2738137 DOI: 10.1128/mmbr.00014-09] [Citation(s) in RCA: 431] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Streptococci readily colonize mucosal tissues in the nasopharynx; the respiratory, gastrointestinal, and genitourinary tracts; and the skin. Each ecological niche presents a series of challenges to successful colonization with which streptococci have to contend. Some species exist in equilibrium with their host, neither stimulating nor submitting to immune defenses mounted against them. Most are either opportunistic or true pathogens responsible for diseases such as pharyngitis, tooth decay, necrotizing fasciitis, infective endocarditis, and meningitis. Part of the success of streptococci as colonizers is attributable to the spectrum of proteins expressed on their surfaces. Adhesins enable interactions with salivary, serum, and extracellular matrix components; host cells; and other microbes. This is the essential first step to colonization, the development of complex communities, and possible invasion of host tissues. The majority of streptococcal adhesins are anchored to the cell wall via a C-terminal LPxTz motif. Other proteins may be surface anchored through N-terminal lipid modifications, while the mechanism of cell wall associations for others remains unclear. Collectively, these surface-bound proteins provide Streptococcus species with a "coat of many colors," enabling multiple intimate contacts and interplays between the bacterial cell and the host. In vitro and in vivo studies have demonstrated direct roles for many streptococcal adhesins as colonization or virulence factors, making them attractive targets for therapeutic and preventive strategies against streptococcal infections. There is, therefore, much focus on applying increasingly advanced molecular techniques to determine the precise structures and functions of these proteins, and their regulatory pathways, so that more targeted approaches can be developed.
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Affiliation(s)
- Angela H Nobbs
- Oral Microbiology Unit, Department of Oral and Dental Science, University of Bristol, Bristol BS1 2LY, United Kingdom
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40
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Comprehensive evaluation of Streptococcus sanguinis cell wall-anchored proteins in early infective endocarditis. Infect Immun 2009; 77:4966-75. [PMID: 19703977 DOI: 10.1128/iai.00760-09] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Streptococcus sanguinis is a member of the viridans group of streptococci and a leading cause of the life-threatening endovascular disease infective endocarditis. Initial contact with the cardiac infection site is likely mediated by S. sanguinis surface proteins. In an attempt to identify the proteins required for this crucial step in pathogenesis, we searched for surface-exposed, cell wall-anchored proteins encoded by S. sanguinis and then used a targeted signature-tagged mutagenesis (STM) approach to evaluate their contributions to virulence. Thirty-three predicted cell wall-anchored proteins were identified-a number much larger than those found in related species. The requirement of each cell wall-anchored protein for infective endocarditis was assessed in the rabbit model. It was found that no single cell wall-anchored protein was essential for the development of early infective endocarditis. STM screening was also employed for the evaluation of three predicted sortase transpeptidase enzymes, which mediate the cell surface presentation of cell wall-anchored proteins. The sortase A mutant exhibited a modest (approximately 2-fold) reduction in competitiveness, while the other two sortase mutants were indistinguishable from the parental strain. The combined results suggest that while cell wall-anchored proteins may play a role in S. sanguinis infective endocarditis, strategies designed to interfere with individual cell wall-anchored proteins or sortases would not be effective for disease prevention.
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Jakubovics NS, Brittan JL, Dutton LC, Jenkinson HF. Multiple adhesin proteins on the cell surface of Streptococcus gordonii are involved in adhesion to human fibronectin. MICROBIOLOGY-SGM 2009; 155:3572-3580. [PMID: 19661180 PMCID: PMC2885655 DOI: 10.1099/mic.0.032078-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Adhesion of bacterial cells to fibronectin (FN) is thought to be a pivotal step in the pathogenesis of invasive infectious diseases. Viridans group streptococci such as Streptococcus gordonii are considered commensal members of the oral microflora, but are important pathogens in infective endocarditis. S. gordonii expresses a battery of cell-surface adhesins that act alone or in concert to bind host receptors. Here, we employed molecular genetic approaches to determine the relative contributions of five known S. gordonii surface proteins to adherence to human FN. Binding levels to FN by isogenic mutants lacking Hsa glycoprotein were reduced by 70 %, while mutants lacking CshA and CshB fibrillar proteins showed approximately 30 % reduced binding. By contrast, disruption of antigen I/II adhesin genes sspA and sspB in a wild-type background did not result in reduced FN binding. Enzymic removal of sialic acids from FN led to reduced S. gordonii DL1 adhesion (>50 %), but did not affect binding by the hsa mutant, indicating that Hsa interacts with sialic acid moieties on FN. Conversely, desialylation of FN did not affect adherence levels of Lactococcus lactis cells expressing SspA or SspB polypeptides. Complementation of the hsa mutant partially restored adhesion to FN. A model is proposed for FN binding by S. gordonii in which Hsa and CshA/CshB are primary adhesins, and SspA or SspB play secondary roles. Understanding the basis of oral streptococcal interactions with FN will provide a foundation for development of new strategies to control infective endocarditis.
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Affiliation(s)
- Nicholas S. Jakubovics
- School of Dental Sciences, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4BW, UK
| | - Jane L. Brittan
- Department of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, UK
| | - Lindsay C. Dutton
- Department of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, UK
| | - Howard F. Jenkinson
- Department of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, UK
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Abstract
Streptococci are clinically important Gram-positive bacteria that are capable to cause a wide variety of diseases in humans and animals. Phylogenetic analyses based on 16S rRNA sequences of the streptococcal species reveal a clustering pattern, reflecting, with a few exceptions, their pathogenic potential and ecological preferences. Microbial adhesion to host tissues is the initial critical event in the pathogenesis of most infections. Streptococci use multiple adhesins to attach to the epithelium, and their expression is regulated in response to environmental and growth conditions. Bacterial adhesins recognize and bind cell surface molecules and extracellular matrix components through specific domains that for certain adhesin families have been well defined and found conserved across the streptococcal species. In this review, we present the different streptococcal adhesin families categorized on the basis of their adhesive properties and structural characteristics, and, when available, we focus the attention on conserved functional domains.
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Affiliation(s)
- Monica Moschioni
- Novartis Vaccines and Diagnostics, Via Fiorentina 1, Siena, Italy
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Davies JR, Svensäter G, Herzberg MC. Identification of novel LPXTG-linked surface proteins from Streptococcus gordonii. MICROBIOLOGY-SGM 2009; 155:1977-1988. [PMID: 19383683 DOI: 10.1099/mic.0.027854-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Surface adhesion plays an essential part in the survival of the commensal organism Streptococcus gordonii in the oral cavity as well as during opportunistic infections such as endocarditis. At least two types of cell surface protein involved in adhesion are found on the surface of Gram-positive bacteria: those anchored via an LPXTG motif by the enzyme sortase A (SrtA) and those associated with the cell surface by, as yet, unknown mechanisms. In srtA(-) mutants, LPXTG-containing proteins have been shown to be released rather than cross-linked to the cell wall. We have therefore used 2D gel electrophoresis of released proteins from an srtA(-) mutant as well as the wild-type strain, followed by peptide identification by MS, to identify a set of novel proteins predicted to be present on the surface of S. gordonii DL1. This includes two large LPXTG-linked proteins (SGO_0707 and SGO_1487), which both contain tandemly repeated sequences similar to those present in known fibrillar adhesins. A 5'-nucleotidase and a protein with a putative collagen-binding domain, both containing LPXTG motifs, were also identified. Anchorless proteins with known chaperone, stress response and elongation factor functions, apparently responsible for bacterial binding to keratinocytes and saliva-coated surfaces in the absence of the LPXTG-linked adhesins, were also associated with the cell surface. These data reveal a range of proteins to be present on the S. gordonii DL1 cell surface, the expression of which plays an important role in adhesion to epithelia and which represent likely candidates for novel virulence factors in S. gordonii.
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Affiliation(s)
- Julia R Davies
- Department of Oral Biology, Faculty of Odontology, Malmö University, Carl Gustavs väg 34, Malmö S-20506, Sweden
| | - Gunnel Svensäter
- Department of Oral Biology, Faculty of Odontology, Malmö University, Carl Gustavs väg 34, Malmö S-20506, Sweden
| | - Mark C Herzberg
- Mucosal and Vaccine Research Center, Minneapolis VA Medical Center, Minneapolis, MN 55417, USA.,Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA
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Binding of the Streptococcus gordonii DL1 surface protein Hsa to the host cell membrane glycoproteins CD11b, CD43, and CD50. Infect Immun 2008; 76:4686-91. [PMID: 18678668 DOI: 10.1128/iai.00238-08] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infective endocarditis is frequently attributed to oral streptococci. The mechanisms of pathogenesis, however, are not well understood, although interaction between streptococci and phagocytes are thought to be very important. A highly expressed surface component of Streptococcus gordonii, Hsa, which has sialic acid-binding activity, contributes to infective endocarditis in vivo. In the present study, we found that S. gordonii DL1 binds to HL-60 cells differentiated into monocytes, granulocytes, and macrophages. Using a glutathione S-transferase (GST) fusion to the NR2 domain, which is the sialic acid-binding region of Hsa, we confirmed that the Hsa NR2 domain also binds to differentiated HL-60 cells. To identify which sialoglycoproteins on the surface of differentiated HL-60 cells are receptors for Hsa, intrinsic membrane proteins were assessed by bacterial overlay and far-Western blotting. S. gordonii DL1 adhered to 100- to 150-kDa proteins, a reaction that was abolished by neuraminidase treatment. These sialoglycoproteins were identified as CD11b, CD43, and CD50 by GST pull-down assay and immunoprecipitation with each specific monoclonal antibody. These data suggest that S. gordonii DL1 Hsa specifically binds to three glycoproteins as receptors and that this interaction may be the initial bacterial binding step in infective endocarditis by oral streptococci.
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Liu D, Yumoto H, Murakami K, Hirota K, Ono T, Nagamune H, Kayama S, Matsuo T, Miyake Y. The essentiality and involvement of Streptococcus intermedius histone-like DNA-binding protein in bacterial viability and normal growth. Mol Microbiol 2008; 68:1268-82. [PMID: 18410499 DOI: 10.1111/j.1365-2958.2008.06232.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Streptococcus intermedius histone-like DNA-binding protein (Si-HLP) is a homodimeric protein and, conserved with Escherichia coli HU, a well-documented nucleoid-associated protein (NAP). In E. coli, HU plays important roles as both structural and regulatory factors, but it is not essential for E. coli viability. Streptococcal HLP has been found to bind host cells and induce cytokine production, but its physiological role remains poorly defined. In the present study, using gene insertion knockout and tetracycline-regulated antisense RNA expression techniques, we determined whether Si-HLP is essential for bacterial viability and normal growth in S. intermedius. The Si-HLP-downregulated S. intermedius strain showed alterations in its morphology and surface properties. Downregulation of Si-HLP led to an expanded nucleoid to fill the intracellular space. Transcription levels of several genes, including virulence-associated factors, were found to be activated or repressed in the antisense Si-hlp RNA-expressing strain by real-time PCR and reverse-transcription PCR. Collectively, these data suggest that Si-HLP serves as an essential NAP governing the nucleoid architecture and controlling the gene transcription profile in S. intermedius.
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Affiliation(s)
- Dali Liu
- Department of Microbiology, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kumamoto-cho, Tokushima 770-8504, Japan
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Corrigan RM, Rigby D, Handley P, Foster TJ. The role of Staphylococcus aureus surface protein SasG in adherence and biofilm formation. MICROBIOLOGY-SGM 2007; 153:2435-2446. [PMID: 17660408 DOI: 10.1099/mic.0.2007/006676-0] [Citation(s) in RCA: 232] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Staphylococcus aureus colonizes the moist squamous epithelium of the anterior nares. One of the adhesins likely to be responsible is the S. aureus surface protein G (SasG), which has sequence similarity with the proteins Pls (plasmin sensitive) of S. aureus and Aap (accumulation associated protein) of Staphylococcus epidermidis. Expression of SasG by a laboratory strain of S. aureus could not be detected by Western immunoblotting. To enable investigation of SasG, the gene was cloned into two expression vectors, the IPTG-inducible pMUTIN4 and the tetracycline-inducible pALC2073, and introduced into S. aureus. Expression of SasG masked the ability of exponentially grown S. aureus cells expressing protein A (Spa), clumping factor B (ClfB) and the fibronectin binding proteins A and B (FnBPA and FnBPB) to bind to IgG, cytokeratin 10 and fibronectin, respectively. SasG also masked binding to fibrinogen mediated by both ClfB and the FnBPs. Western immunoblotting showed no reduction in expression of the blocked adhesins following induction of SasG. SasG size variants with eight, six or five B repeats masked binding to the ligands, whereas variants with four, two or one repeats had no effect. SasG-expressing strains formed peritrichous fibrils (53.47+/-2.51 nm long) of varying density on the cell wall, which were labelled by immunogold negative staining with anti-SasG antibodies. SasG-expressing strains of S. aureus also formed biofilm independently of the polysaccharide intercellular adhesin (PIA). SasG variants with eight, six and five repeats formed biofilm, whereas variants with four, two or one repeats did not. It was concluded that the fibrillar nature of SasG explains its ability to mask binding of S. aureus microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) to their ligands and to promote formation of biofilm. In addition, the strong adhesion of SasG to desquamated nasal epithelial cells likely compensates for its blocking of the binding of S. aureus ClfB to cytokeratin 10, which is important in adhesion to squames by cells lacking SasG. Several clinical isolates expressed SasG at levels similar to those of SH1000 sasG : : pMUTIN4, indicating that the properties described in the laboratory strain SH1000 may be relevant in vivo.
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Affiliation(s)
- Rebecca M Corrigan
- Microbiology Department, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland
| | - David Rigby
- Faculty of Life Sciences, 1.800 Stopford Building, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Pauline Handley
- Faculty of Life Sciences, 1.800 Stopford Building, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Timothy J Foster
- Microbiology Department, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland
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Yip ES, Geszvain K, DeLoney-Marino CR, Visick KL. The symbiosis regulator rscS controls the syp gene locus, biofilm formation and symbiotic aggregation by Vibrio fischeri. Mol Microbiol 2007; 62:1586-600. [PMID: 17087775 PMCID: PMC1852533 DOI: 10.1111/j.1365-2958.2006.05475.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Successful colonization of a eukaryotic host by a microbe involves complex microbe-microbe and microbe-host interactions. Previously, we identified in Vibrio fischeri a putative sensor kinase, RscS, required for initiating symbiotic colonization of its squid host Euprymna scolopes. Here, we analysed the role of rscS by isolating an allele, rscS1, with increased activity. Multicopy rscS1 activated transcription of genes within the recently identified symbiosis polysaccharide (syp) cluster. Wild-type cells carrying rscS1 induced aggregation phenotypes in culture, including the formation of pellicles and wrinkled colonies, in a syp-dependent manner. Colonies formed by rscSl-expressing cells produced a matrix not found in control colonies and largely lost in an rscSl-expressing sypN mutant. Finally, multicopy rscS1 provided a colonization advantage over control cells and substantially enhanced the ability of wild-type cells to aggregate on the surface of the symbiotic organ of E. scolopes; this latter phenotype similarly depended upon an intact syp locus. These results suggest that transcription induced by RscS-mediated signal transduction plays, a key role in colonization at the aggregation stage by modifying the cell surface and increasing the ability of the cells to adhere to one another and/or to squid-secreted mucus.
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Affiliation(s)
- Emily S Yip
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL, USA
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Razak FA, Othman RY, Rahim ZHA. The effect of Piper betle and Psidium guajava extracts on the cell-surface hydrophobicity of selected early settlers of dental plaque. J Oral Sci 2007; 48:71-5. [PMID: 16858135 DOI: 10.2334/josnusd.48.71] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
The adhesion of early settlers of dental plaque to the tooth surface has a role in the initiation of the development of dental plaque. The hydrophobic surface properties of the bacteria cell wall are indirectly responsible for the adhesion of the bacteria cell to the acquired pellicle on the tooth surfaces. In this study, the effect of aqueous extract of two plants (Psidium guajava and Piper betle) on the cell-surface hydro-phobicity of early settlers of dental plaque was determined in vitro. Hexadecane, a hydrocarbon was used to represent the hydrophobic surface of the teeth in the oral cavity. It was found that treatment of the early plaque settlers with 1 mg/ml extract of Psidium guajava reduced the cell-surface hydrophobicity of Strep. sanguinis, Strep. mitis and Actinomyces sp. by 54.1%, 49.9% and 40.6%, respectively. Treatment of these bacteria with the same concentration of Piper betle however, showed a comparatively lesser effect (< 10%). It was also observed that the anti-adhesive effect of the two extracts on the binding of the early plaque settlers to hexadecane is concentration dependent.
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Affiliation(s)
- Fathilah Abdul Razak
- Department of Oral Biology, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia.
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49
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Positive role of cell wall anchored proteinase PrtP in adhesion of lactococci. BMC Microbiol 2007; 7:36. [PMID: 17474995 PMCID: PMC1876236 DOI: 10.1186/1471-2180-7-36] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Accepted: 05/02/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The first step in biofilm formation is bacterial attachment to solid surfaces, which is dependent on the cell surface physico-chemical properties. Cell wall anchored proteins (CWAP) are among the known adhesins that confer the adhesive properties to pathogenic Gram-positive bacteria. To investigate the role of CWAP of non-pathogen Gram-positive bacteria in the initial steps of biofilm formation, we evaluated the physico-chemical properties and adhesion to solid surfaces of Lactococcus lactis. To be able to grow in milk this dairy bacterium expresses a cell wall anchored proteinase PrtP for breakdown of milk caseins. RESULTS The influence of the anchored cell wall proteinase PrtP on microbial surface physico-chemical properties, and consequently on adhesion, was evaluated using lactococci carrying different alleles of prtP. The presence of cell wall anchored proteinase on the surface of lactococcal cells resulted in an increased affinity to solvents with different physico-chemical properties (apolar and Lewis acid-base solvents). These properties were observed regardless of whether the PrtP variant was biologically active or not, and were not observed in strains without PrtP. Anchored PrtP displayed a significant increase in cell adhesion to solid glass and tetrafluoroethylene surfaces. CONCLUSION Obtained results indicate that exposure of an anchored cell wall proteinase PrtP, and not its proteolytic activity, is responsible for greater cell hydrophobicity and adhesion. The increased bacterial affinity to polar and apolar solvents indicated that exposure of PrtP on lactococcal cell surface could enhance the capacity to exchange attractive van der Waals interactions, and consequently increase their adhesion to different types of solid surfaces and solvents.
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50
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Ahimou F, Boonaert CJP, Adriaensen Y, Jacques P, Thonart P, Paquot M, Rouxhet PG. XPS analysis of chemical functions at the surface of Bacillus subtilis. J Colloid Interface Sci 2007; 309:49-55. [PMID: 17316673 DOI: 10.1016/j.jcis.2007.01.055] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Revised: 01/05/2007] [Accepted: 01/10/2007] [Indexed: 11/26/2022]
Abstract
The surface chemical composition of nine strains of Bacillus subtilis was determined by X-ray photoelectron spectroscopy. Regressions between elemental concentrations and concentrations associated with different components of C1s, N1s, and O1s peaks provided a more precise validation of the procedure used for peak decomposition and allowed the assignment of the peak components to be completed or strengthened. The component of the O1s peak appearing around 531.2 eV was shown to contain a contribution of oxygen from phosphate groups (PO, PO-), the other contribution being due to oxygen involved in amide functions. The surface negative charge may be fully attributed to phosphate groups, despite the observation of two types of zeta potential vs pH curves. The strains exhibiting a sharp variation of the zeta potential (range of -35 to -55 mV) between pH 2 and 4.7 were characterized by a high phosphate surface concentration and by an excess (about 25%) of phosphate with respect to the sum of potassium, an exchangeable cation, and protonated nitrogen, attributed to protein or to alanine involved in teichoic acids.
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Affiliation(s)
- François Ahimou
- Unité de Chimie Biologique Industrielle, Faculté Universitaire des Sciences Agronomiques de Gembloux, Passage des Déportés 2, B-5030 Gembloux, Belgium
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