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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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Surface proteins involved in the adhesion of Streptococcus salivarius to human intestinal epithelial cells. Appl Microbiol Biotechnol 2018; 102:2851-2865. [PMID: 29442170 PMCID: PMC5847202 DOI: 10.1007/s00253-018-8794-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 01/10/2018] [Accepted: 01/14/2018] [Indexed: 01/08/2023]
Abstract
The adhesion properties of 14 Streptococcus salivarius strains to mucus (HT29-MTX) and non-mucus secreting (Caco-2/TC7) human intestinal epithelial cells were investigated. Ability to adhere to these two eukaryotic cell lines greatly differs between strains. The presence of mucus played a major factor in adhesion, likely due to high adhesiveness to mucins present in the native human mucus layer covering the whole cell surface. Only one S. salivarius strain (F6-1), isolated from the feces of a healthy baby, was found to strongly adhere to HT-29 MTX cells at a level comparable to that of Lactobacillus rhamnosus GG, a probiotic strain considered to be highly adherent. By sequencing the genome of F6-1, we were able to identify 36 genes encoding putative surface proteins. Deletion mutants were constructed for six of them and their adhesion abilities on HT-29 MTX cells were checked. Our study confirmed that four of these genes encode adhesins involved in the adhesion of S. salivarius to host cells. Such adhesins were also identified in other S. salivarius strains.
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Couvigny B, Lapaque N, Rigottier-Gois L, Guillot A, Chat S, Meylheuc T, Kulakauskas S, Rohde M, Mistou MY, Renault P, Doré J, Briandet R, Serror P, Guédon E. Three glycosylated serine-rich repeat proteins play a pivotal role in adhesion and colonization of the pioneer commensal bacterium,Streptococcus salivarius. Environ Microbiol 2017; 19:3579-3594. [DOI: 10.1111/1462-2920.13853] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 06/29/2017] [Accepted: 06/30/2017] [Indexed: 01/25/2023]
Affiliation(s)
- Benoit Couvigny
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Nicolas Lapaque
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Lionel Rigottier-Gois
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Alain Guillot
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Sophie Chat
- INRA, Plateforme MIMA2; Jouy-en-josas France
| | - Thierry Meylheuc
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
- INRA, Plateforme MIMA2; Jouy-en-josas France
| | - Saulius Kulakauskas
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Manfred Rohde
- HZI, Helmholtz Centre for Infection Research; Braunschweig Germany
| | - Michel-Yves Mistou
- Laboratory for Food Safety; Université Paris-Est, ANSES; Maisons-Alfort France
| | - Pierre Renault
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Joel Doré
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Romain Briandet
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Pascale Serror
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Eric Guédon
- STLO, UMR1253, INRA, Agrocampus Ouest; Rennes France
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Delorme C, Abraham AL, Renault P, Guédon E. Genomics of Streptococcus salivarius, a major human commensal. INFECTION GENETICS AND EVOLUTION 2014; 33:381-92. [PMID: 25311532 DOI: 10.1016/j.meegid.2014.10.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/30/2014] [Accepted: 10/02/2014] [Indexed: 10/24/2022]
Abstract
The salivarius group of streptococci is of particular importance for humans. This group consists of three genetically similar species, Streptococcus salivarius, Streptococcus vestibularis and Streptococcus thermophilus. S. salivarius and S. vestibularis are commensal organisms that may occasionally cause opportunistic infections in humans, whereas S. thermophilus is a food bacterium widely used in dairy production. We developed Multilocus sequence typing (MLST) and comparative genomic analysis to confirm the clear separation of these three species. These analyses also identified a subgroup of four strains, with a core genome diverging by about 10%, in terms of its nucleotide sequence, from that of S. salivarius sensu stricto. S. thermophilus species displays a low level of nucleotide variability, due to its recent emergence with the development of agriculture. By contrast, nucleotide variability is high in the other two species of the salivarius group, reflecting their long-standing association with humans. The species of the salivarius group have genome sizes ranging from the smallest (∼ 1.7 Mb for S. thermophilus) to the largest (∼ 2.3 Mb for S. salivarius) among streptococci, reflecting genome reduction linked to a narrow, nutritionally rich environment for S. thermophilus, and natural, more competitive niches for the other two species. Analyses of genomic content have indicated that the core genes of S. salivarius account for about two thirds of the genome, indicating considerable variability of gene content and differences in potential adaptive features. Furthermore, we showed that the genome of this species is exceptionally rich in genes encoding surface factors, glycosyltransferases and response regulators. Evidence of widespread genetic exchanges was obtained, probably involving a natural competence system and the presence of diverse mobile elements. However, although the S. salivarius strains studied were isolated from several human body-related sites (all levels of the digestive tract, skin, breast milk, and body fluids) and included clinical strains, no genetic or genomic niche-specific features could be identified to discriminate specific group.
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Affiliation(s)
- Christine Delorme
- INRA, UMR 1319 Micalis, Domaine de Vilvert, F-78352 Jouy-en-Josas, France; AgroParisTech, UMR MICALIS, Jouy-en-Josas, France
| | - Anne-Laure Abraham
- INRA, UMR 1319 Micalis, Domaine de Vilvert, F-78352 Jouy-en-Josas, France; AgroParisTech, UMR MICALIS, Jouy-en-Josas, France
| | - Pierre Renault
- INRA, UMR 1319 Micalis, Domaine de Vilvert, F-78352 Jouy-en-Josas, France; AgroParisTech, UMR MICALIS, Jouy-en-Josas, France
| | - Eric Guédon
- INRA, UMR 1319 Micalis, Domaine de Vilvert, F-78352 Jouy-en-Josas, France; AgroParisTech, UMR MICALIS, Jouy-en-Josas, France.
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Wang Y, Lee SM, Dykes GA. Growth in the presence of sucrose may decrease attachment of some oral bacteria to abiotic surfaces. ANN MICROBIOL 2014. [DOI: 10.1007/s13213-014-0883-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Wang Y, Chung FFL, Lee SM, Dykes GA. Inhibition of attachment of oral bacteria to immortalized human gingival fibroblasts (HGF-1) by tea extracts and tea components. BMC Res Notes 2013; 6:143. [PMID: 23578062 PMCID: PMC3637544 DOI: 10.1186/1756-0500-6-143] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Accepted: 04/03/2013] [Indexed: 01/30/2023] Open
Abstract
Background Tea has been suggested to promote oral health by inhibiting bacterial attachment to the oral cavity. Most studies have focused on prevention of bacterial attachment to hard surfaces such as enamel. Findings This study investigated the effect of five commercial tea (green, oolong, black, pu-erh and chrysanthemum) extracts and tea components (epigallocatechin gallate and gallic acid) on the attachment of five oral pathogens (Streptococcus mutans ATCC 25175, Streptococcus mutans ATCC 35668, Streptococcus mitis ATCC 49456, Streptococcus salivarius ATCC 13419 and Actinomyces naeslundii ATCC 51655) to the HGF-1 gingival cell line. Extracts of two of the teas (pu-erh and chrysanthemum) significantly (p < 0.05) reduced attachment of all the Streptococcus strains by up to 4 log CFU/well but effects of other teas and components were small. Conclusions Pu-erh and chrysanthemum tea may have the potential to reduce attachment of oral pathogens to gingival tissue and improve the health of oral soft tissues.
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Affiliation(s)
- Yi Wang
- School of Science, Monash University, Jalan Lagoon Selatan, Bandar Sunway, 46150, Selangor, Malaysia
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Protective mechanisms of respiratory tract Streptococci against Streptococcus pyogenes biofilm formation and epithelial cell infection. Appl Environ Microbiol 2012; 79:1265-76. [PMID: 23241973 DOI: 10.1128/aem.03350-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Streptococcus pyogenes (group A streptococci [GAS]) encounter many streptococcal species of the physiological microbial biome when entering the upper respiratory tract of humans, leading to the question how GAS interact with these bacteria in order to establish themselves at this anatomic site and initiate infection. Here we show that S. oralis and S. salivarius in direct contact assays inhibit growth of GAS in a strain-specific manner and that S. salivarius, most likely via bacteriocin secretion, also exerts this effect in transwell experiments. Utilizing scanning electron microscopy documentation, we identified the tested strains as potent biofilm producers except for GAS M49. In mixed-species biofilms, S. salivarius dominated the GAS strains, while S. oralis acted as initial colonizer, building the bottom layer in mixed biofilms and thereby allowing even GAS M49 to form substantial biofilms on top. With the exception of S. oralis, artificial saliva reduced single-species biofilms and allowed GAS to dominate in mixed biofilms, although the overall two-layer structure was unchanged. When covered by S. oralis and S. salivarius biofilms, epithelial cells were protected from GAS adherence, internalization, and cytotoxic effects. Apparently, these species can have probiotic effects. The use of Affymetrix array technology to assess HEp-2 cell transcription levels revealed modest changes after exposure to S. oralis and S. salivarius biofilms which could explain some of the protective effects against GAS attack. In summary, our study revealed a protection effect of respiratory tract bacteria against an important airway pathogen and allowed a first in vitro insight into local environmental processes after GAS enter the respiratory tract.
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Crawford I, Russell C. The Effect of Pretreatment of Streptococci with Protease, Lipase and Antibiotics on Adhesion to Fibrin Clotsin vitro. MICROBIAL ECOLOGY IN HEALTH AND DISEASE 2009. [DOI: 10.3109/08910608809140531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- I. Crawford
- Microbiology Department, Stepping Hill Hospital, Stockport, Cheshire, UK
| | - C. Russell
- Department of Oral Medicine, University of Manchester, Manchester, UK
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Köller T, Nelson D, Nakata M, Kreutzer M, Fischetti VA, Glocker MO, Podbielski A, Kreikemeyer B. PlyC, a novel bacteriophage lysin for compartment-dependent proteomics of group A streptococci. Proteomics 2008; 8:140-8. [PMID: 18095374 DOI: 10.1002/pmic.200700001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Streptococcus pyogenes (Spy) (group A streptococci) is an important and exclusively human bacterial pathogen, which uses secreted and surface-associated proteins to circumvent the innate host defense mechanisms and to adhere and internalize into host cells. Thus, investigation of the bacterial extracellular compartments, including secreted and cell wall-associated subproteomes, is crucial for understanding adherence, invasion, and internalization mechanisms as major steps of Spy pathogenesis. Here, we compared a bacteriophage encoded cell wall hydrolase, PlyC, a multimeric lysin of the C1 bacteriophage, with the established glycosidase, mutanolysin, from Streptomyces globisporus for their suitability to efficiently digest Spy cell walls and release cell wall-anchored Spy proteins for subsequent proteome research. Our results show that PlyC is superior for cell wall protein extraction compared to mutanolysin due to its higher activity and specificity as an N-acetylmuramoyl-L-alanine amidase. Furthermore, our experimental design allowed us to delineate the actual localization of the proteins despite contamination with intracellular proteins.
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Affiliation(s)
- Thomas Köller
- Department of Medical Microbiology and Hospital Hygiene, Hospital of Rostock University, Schillingallee 70, Rostock, Germany
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Duval JFL, Busscher HJ, van de Belt-Gritter B, van der Mei HC, Norde W. Analysis of the interfacial properties of fibrillated and nonfibrillated oral streptococcal strains from electrophoretic mobility and titration measurements: evidence for the shortcomings of the 'classical soft-particle approach'. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:11268-82. [PMID: 16285800 DOI: 10.1021/la051735q] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Chemical and structural intricacies of bacterial cells complicate the quantitative evaluation of the physicochemical properties pertaining to the cell surface. The presence of various types of cell surface appendages has a large impact on those properties and therefore on various interfacial phenomena, such as aggregation and adhesion. In this paper, an advanced analysis of the electrophoretic mobilities of fibrillated and nonfibrillated strains (Streptococcus salivarius HB and Streptococcus salivarius HB-C12, respectively) is performed over a wide range of pH and ionic strength conditions on the basis of a recent electrokinetic theory for soft particles. The latter extends the approximate formalism originally developed by Ohshima by solving rigorously the fundamental electrokinetic equations without restrictions on the bacterial size, charge, and double layer thickness. It further allows (i) a straightforward implementation of the dissociation characteristics, as evaluated from titration experiments, of the ionogenic charged groups distributed throughout the bacterial cell wall and/or the surrounding exopolymer layer and (ii) the inclusion of possible specific interactions between the charged groups and ions from the background electrolyte other than charge-determining ions. The theory also enables an estimation of possible swelling/shrinking processes operating on the outer polymeric layer of the bacterium. Application of the electrokinetic model to HB and HB-C12 clearly shows a significant discrepancy between the amount of surface charges probed by electrophoresis and by protolytic titration. This is ascribed to the specific adsorption of cations onto pristine charged sites in the cell wall. Physicochemical parameters pertaining to the hydrodynamics (softness degree) and electrostatics of the bacterial cell wall (HB-C12) and soft polymeric layer (HB) are quantitatively derived.
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Affiliation(s)
- Jérôme F L Duval
- CABE (Analytical and Biophysical Environmental Chemistry), University of Geneva, Sciences II, 30 Quai E. Ansermet, Switzerland
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Lévesque C, Lamothe J, Frenette M. Coaggregation of Streptococcus salivarius with periodontopathogens: evidence for involvement of fimbriae in the interaction with Prevotella intermedia. ORAL MICROBIOLOGY AND IMMUNOLOGY 2003; 18:333-7. [PMID: 12930529 DOI: 10.1034/j.1399-302x.2003.00085.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Streptococcus salivarius is divided into two serological subgroups that carry either fibrils or fimbriae. Although fimbriae have been observed on up to 50% of S. salivarius strains in the human oral cavity, no function has yet been assigned to them. To determine whether S. salivarius fimbriae have a role in adhesion, we examined the ability of S. salivarius to coaggregate with selected microorganisms involved in periodontal diseases. Our results show that S. salivarius coaggregated with Fusobacterium nucleatum, Porphyromonas gingivalis, and Prevotella intermedia. However, only fimbriated S. salivarius cells were able to coaggregate with P. intermedia, suggesting a specific role for these structures in the interaction. Heat treatment, sensitivity to sugars, amino acids, and EDTA, as well as protease treatment were also used to further characterize coaggregation between S. salivarius and periodontopathogens.
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Affiliation(s)
- C Lévesque
- Groupe de Recherche en Ecologie Buccale (GREB), Faculté de Médecine Dentaire and Département de Biochimie et de Microbiologie, Université Laval, Québec City, Canada
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Elliott D, Harrison E, Handley PS, Ford SK, Jaffray E, Mordan N, McNab R. Prevalence of Csh-like fibrillar surface proteins among mitis group oral streptococci. ORAL MICROBIOLOGY AND IMMUNOLOGY 2003; 18:114-20. [PMID: 12654102 DOI: 10.1034/j.1399-302x.2003.00052.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The prevalence of Csh-like fibrillar surface proteins among oral streptococci was investigated by ELISA and by immunoelectron microscopy using antiserum raised to recombinant fragments of CshA of Streptococcus gordonii DL1. The majority of S. gordonii, Streptococcus sanguis and Streptococcus oralis strains tested elaborated short (ca. 50-80 nm long) surface fibrils and reacted with antiserum to the amino acid repeat region of CshA, demonstrating the widespread nature of Csh-like proteins among these species. In contrast, reactivity with antiserum raised to the adhesion-mediating non-repetitive region of CshA was more restricted. On the basis of the ELISA results, several isolates were selected for immunogold analysis using CshA antisera. Immunogold-negative staining showed a surface distribution of 10 nm gold particles consistent with antibody binding to short fibrils. Long fibrils (>150 nm long), where present, were not significantly labelled with gold. The results suggest that some of the short peritrichous fibrils on many mitis group streptococci comprise Csh-like fibrillar protein. Further, the data are consistent with our hypothesis that the antigenically conserved amino acid repeat region of Csh-like proteins forms a scaffold for cell-distal presentation of the amino-terminal non-repetitive region that, at least in S. gordonii DL1, functions as an adhesin.
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Affiliation(s)
- D Elliott
- Department of Biological Sciences, Manchester University, Manchester, UK
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Ray CA, Gfell LE, Buller TL, Gregory RL. Interactions of Streptococcus mutans fimbria-associated surface proteins with salivary components. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1999; 6:400-4. [PMID: 10225843 PMCID: PMC103730 DOI: 10.1128/cdli.6.3.400-404.1999] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Streptococcus mutans has been implicated as the major causative agent of human dental caries. S. mutans binds to saliva-coated tooth surfaces, and previous studies suggested that fimbriae may play a role in the initial bacterial adherence to salivary components. The objectives of this study were to establish the ability of an S. mutans fimbria preparation to bind to saliva-coated surfaces and determine the specific salivary components that facilitate binding with fimbriae. Enzyme-linked immunosorbent assay (ELISA) established that the S. mutans fimbria preparation bound to components of whole saliva. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot techniques were used to separate components of whole saliva and determine fimbria binding. SDS-PAGE separated 15 major protein bands from saliva samples, and Western blot analysis indicated significant binding of the S. mutans fimbria preparation to a 52-kDa salivary protein. The major fimbria-binding salivary protein was isolated by preparative electrophoresis. The ability of the S. mutans fimbria preparation to bind to the purified salivary protein was confirmed by Western blot analysis and ELISA. Incubation of the purified salivary protein with the S. mutans fimbria preparation significantly neutralized binding of the salivary protein-fimbria complex to saliva-coated surfaces. The salivary protein, whole saliva, and commercial amylase reacted similarly with antiamylase antibody in immunoblots. A purified 65-kDa fimbrial protein was demonstrated to bind to both saliva and amylase. These data indicated that the S. mutans fimbria preparation and a purified fimbrial protein bound to whole-saliva-coated surfaces and that amylase is the major salivary component involved in the binding.
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Affiliation(s)
- C A Ray
- Department of Oral Biology, School of Dentistry, Indiana University, Indianapolis, Indiana 46202-5186, USA
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Bos R, van der Mei HC, Busscher HJ. 'Soft-particle' analysis of the electrophoretic mobility of a fibrillated and non-fibrillated oral streptococcal strain: Streptococcus salivarius. Biophys Chem 1998; 74:251-5. [PMID: 9779584 DOI: 10.1016/s0301-4622(98)00189-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electrophoretic mobility of microbial cell surfaces can be analysed in terms of a so-called soft layer model, in which the electrophoretic mobility is described as originating from the potentials over the surface charge layer and the membrane fixed charges. Often, the polyelectrolyte layer deforms under the influence of ionic strength variations. In the soft layer analysis of electrophoretic mobilities this is expressed in the softness 1/lambda. Here, we determined the softness of two oral streptococcal strains, S. salivarius HB and HBC12 from particulate microelectrophoresis in KCl solutions of varying ionic strength. Electron microscopy of negatively-stained organisms and X-ray photoelectron spectroscopy showed that strain HB had several classes of proteinaceous fibrils with lengths up to 178 nm on its outermost surface, while variant HBC12 had a bald, peptidoglycan-rich outer surface. The fibrillated strain HB appeared as relatively soft (1/lambda equals 1.4 nm) from analysis of its electrophoretic mobility, while the bald variant HBC12 was hard (1/lambda equals 0.7 nm) due to its comparatively rigid, peptidoglycan-rich outer surface, characteristic to Gram-positive bacteria. The presence of proteinaceous fibrils on strain HB slightly shielded the membrane fixed charges on HBC12.
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Affiliation(s)
- R Bos
- Laboratory for Materia Technica, University of Groningen, The Netherlands.
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Jenkinson HF, Lamont RJ. Streptococcal adhesion and colonization. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 1997; 8:175-200. [PMID: 9167092 DOI: 10.1177/10454411970080020601] [Citation(s) in RCA: 217] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Streptococci express arrays of adhesins on their cell surfaces that facilitate adherence to substrates present in their natural environment within the mammalian host. A consequence of such promiscuous binding ability is that streptococcal cells may adhere simultaneously to a spectrum of substrates, including salivary glycoproteins, extracellular matrix and serum components, host cells, and other microbial cells. The multiplicity of streptococcal adherence interactions accounts, at least in part, for their success in colonizing the oral and epithelial surfaces of humans. Adhesion facilitates colonization and may be a precursor to tissue invasion and immune modulation, events that presage the development of disease. Many of the streptococcal adhesins and virulence-related factors are cell-wall-associated proteins containing repeated sequence blocks of amino acids. Linear sequences, both within the blocks and within non-repetitive regions of the proteins, have been implicated in substrate binding. Sequences and functions of these proteins among the streptococci have become assorted through gene duplication and horizontal transfer between bacterial populations. Several adhesins identified and characterized through in vitro binding assays have been analyzed for in vivo expression and function by means of animal models used for colonization and virulence. Information on the molecular structure of adhesins as related to their in vivo function will allow for the rational design of novel acellular vaccines, recombinant antibodies, and adhesion agonists for the future control or prevention of streptococcal colonization and streptococcal diseases.
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Affiliation(s)
- H F Jenkinson
- Department of Oral Biology and Oral Pathology, University of Otago, Dunedin, New Zealand
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Fontana M, Gfell LE, Gregory RL. Characterization of preparations enriched for Streptococcus mutans fimbriae: salivary immunoglobulin A antibodies in caries-free and caries-active subjects. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1995; 2:719-25. [PMID: 8574837 PMCID: PMC170228 DOI: 10.1128/cdli.2.6.719-725.1995] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The ability of bacteria to adhere to salivary pellicle-coated enamel tooth surfaces is a critical step in oral bacterial colonization. Oral bacteria adhere to receptors of host origin in salivary pellicle. Streptococcus mutans has been identified as the major etiological agent of human dental caries and composes a significant proportion of the oral streptococci in carious lesions. Bacterial fimbriae are small (100 to 300 nm) hairlike appendages emanating from the cell surface. Preparations enriched for S. mutans fimbriae were isolated by a shearing technique and alternating high- and low-speed centrifugations. A representative fimbrial preparation had two distinct double bands comprising four proteins of approximately 100 to 200 kDa and one faint band at 40 kDa on reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis/immunoblots and had demonstrable glucosyltransferase activity. Rabbit antisera raised against the preparation specifically stained the fuzzy coat of S. mutans, demonstrating short fimbria-like structures protruding 100 to 200 nm from the cell surface. Controls without antifimbria antibody did not exhibit this staining. There were significantly higher (P < or = 0.05) levels of salivary immunoglobulin A, but not serum immunoglobulin G, antibodies to the enriched S. mutans fimbria preparation by enzyme-linked immunosorbent assay from caries-free subjects than from caries-active subjects. The results suggest that S. mutans fimbriae may be an important adherence factor to which caries-free subjects mount a protective salivary immune response.
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Affiliation(s)
- M Fontana
- Department of Oral Biology, Indiana University, Indianapolis 46202, USA
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17
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MEYER HEINZGEORGWILHELM, GATERMANN SÖREN. Surface properties ofStaphylococcus saprophyticus:hydrophobicity, haemagglutination andStaphylococcus saprophyticussurface-associated protein (Ssp) represent distinct entities. APMIS 1994. [DOI: 10.1111/j.1699-0463.1994.tb05203.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Kehoe MA. Chapter 11 Cell-wall-associated proteins in Gram-positive bacteria. BACTERIAL CELL WALL 1994. [DOI: 10.1016/s0167-7306(08)60414-7] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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19
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Erickson P, Herzberg M. Evidence for the covalent linkage of carbohydrate polymers to a glycoprotein from Streptococcus sanguis. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(20)80451-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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20
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Busscher HJ, Geertsema-Doornbusch GI, van der Mei HC. On mechanisms of oral microbial adhesion. THE JOURNAL OF APPLIED BACTERIOLOGY 1993; 74 Suppl:136S-142S. [PMID: 8349532 DOI: 10.1111/j.1365-2672.1993.tb04350.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- H J Busscher
- Materia Technica, University of Groningen, The Netherlands
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21
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McNab R, Jenkinson HF. Gene disruption identifies a 290 kDa cell-surface polypeptide conferring hydrophobicity and coaggregation properties in Streptococcus gordonii. Mol Microbiol 1992; 6:2939-49. [PMID: 1479886 DOI: 10.1111/j.1365-2958.1992.tb01753.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The C-terminal coding region of the gene (denoted cshA) encoding a high-molecular-mass (290 kDa) cell-surface polypeptide in the oral bacterium Streptococcus gordonii was cloned and sequenced. Insertion of ermAM into the S. gordonii chromosome at the 3' end of the coding region of cshA led to the production of isogenic mutants that secreted a truncated form (260 kDa) of the CshA polypeptide into the growth medium. Mutants had reduced cell-surface hydrophobicity and were impaired in their ability to coaggregate with oral actinomyces. The results identify a carboxyl terminus-anchored cell-surface protein determinant of hydrophobicity and coaggregation in S. gordonii.
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Affiliation(s)
- R McNab
- Department of Oral Biology and Oral Pathology, University of Otago, Dunedin, New Zealand
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22
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Busscher HJ, Cowan MM, van der Mei HC. On the relative importance of specific and non-specific approaches to oral microbial adhesion. FEMS Microbiol Rev 1992; 8:199-209. [PMID: 1515160 DOI: 10.1111/j.1574-6968.1992.tb04988.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In this paper, it is suggested that specificity and non-specificity in (oral) microbial adhesion are different expressions for the same phenomena. It is argued that the same basic, physicochemical forces are responsible for so-called 'non-specific' and 'specific' binding and that from a physico-chemical point of view the distinction between the two is an artificial one. Non-specific interactions arise from Van der Waals and electrostatic forces and hydrogen bonding, and originate from the entire cell. A specific bond consists of a combination of the same type of Van der Waals and electrostatic forces and hydrogen bonding, now originating from highly localized chemical groups, which together form a stereochemical combination. The absence or presence of specific receptor sites on microbial cell surfaces must therefore be reflected in the overall, non-specific surface properties of cells as well. This point is illustrated by showing that glucan-binding lectins on mutans streptococcal strains may determine the pH dependence of the zeta potentials of these cells. When studying microbial adhesion, a non-specific approach may be better suited to explain adhesion to inert substrata, whereas a specific approach may be preferred in case of adhesion to adsorbed protein films. Adhesion is, however, not as important in plaque formation in the human oral cavity as is retention, because low shear force periods, during which adhesion presumably occurs, are followed by high shear force periods, during which adhering cells must withstand these detachment forces. Evidence is provided that such detachment will be through cohesive failure in the pellicle mass, the properties of which are conditioned by the overall, non-specific substratum properties. Therefore, in vivo plaque formation may be more readily explained by a non-specific approach.
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Affiliation(s)
- H J Busscher
- Laboratory for Materia Technica, University of Groningen, Netherlands
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23
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Gatermann S, Kreft B, Marre R, Wanner G. Identification and characterization of a surface-associated protein (Ssp) of Staphylococcus saprophyticus. Infect Immun 1992; 60:1055-60. [PMID: 1541520 PMCID: PMC257593 DOI: 10.1128/iai.60.3.1055-1060.1992] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
A 95-kDa protein was isolated from Staphylococcus saprophyticus 7108 grown on dialysis membranes placed on the surface of brain heart infusion agar. Strain CCM883 did not produce this protein. Ultrathin sections revealed the presence of very thin, tuftlike, 50- to 75-nm-long structures on the surface of strain 7108, whereas strain CCM883 was comparably smooth. The surface material could be removed by digestion with proteinase K, suggesting that the surface structures contain protein. High-resolution scanning electron microscopy showed a thick layer of surface material on strain 7108, whereas strain CCM883 appeared smooth. The 95-kDa protein was purified by Sephacryl S-300 chromatography, and an antiserum was raised in rabbits. This antiserum was used in immunogold labeling experiments, which showed that the protein is associated with the surface structures. Our experiments thus demonstrate the presence of a fibrillar protein on the surface of S. saprophyticus (Ssp for S. saprophyticus surface-associated protein).
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Affiliation(s)
- S Gatermann
- Institut für Medizinische Mikrobiologie, Medizinischen Universität zu Lübeck, Germany
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24
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van der Mei HC, Handley PS, Busscher HJ. Depth profiling of the elemental surface composition of the oral microorganism S. salivarius HB and fibrillar mutants by X-ray photoelectron spectroscopy. CELL BIOPHYSICS 1992; 20:99-110. [PMID: 1284785 DOI: 10.1007/bf02782657] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
X-ray photoelectron spectroscopy (XPS) on microbial cell surfaces requires freeze-drying of cells, and as a result, the cell surface appendages flatten out on the cell surface and form a collapsed fibrillar mass. At present, it is unclear how the density, length and composition of these fibrils influence the elemental surface composition as probed by XPS. The sampling depth of XPS can be varied by changing the electron take-off angle. In this article, we made a depth profiling of the collapsed fibrillar mass of Streptococcus salivarius HB and fibril-deficient mutants by angle-dependent XPS. Methylamine tungstate negative staining and ruthenium red staining followed by sectioning revealed distinct classes of fibrils with various lengths on each of the strains. Interpretation of the angle dependence of the oxygen/carbon (O/C) and phosphorus/carbon (P/C) surface concentration ratios of these strains was difficult. However, the angle dependence of the nitrogen/carbon (N/C) surface concentration ratio could be fully interpreted: N/C did not vary with sampling depth on a bald strain, S. salivarius HBC12 and on S. salivarius HB7, a strain with a dense array of fibrils of uniform length. N/C decreased with sampling depth in case of a sparsely fibrillated strain, S. salivarius HBV51 and eventually reached the value observed for the bald strain, HBC12. A high N/C at small sampling depth was observed for S. salivarius HB with protruding, protein rich fibrils. We conclude that elemental depth profiling of microbial cell surfaces by XPS can be interpreted to coincide with structural and biochemical information on the cell surface as obtained by electron microscopy and can therefore be considered as a useful technique to study structural features of cell surfaces in combination with electron microscopy.
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Affiliation(s)
- H C van der Mei
- Laboratory for Materia Technica, University of Groningen, The Netherlands
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25
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Willcox MD, Knox KW, Green RM, Drucker DB. An examination of strains of the bacterium Streptococcus vestibularis for relative cariogenicity in gnotobiotic rats and adhesion in vitro. Arch Oral Biol 1991; 36:327-33. [PMID: 1651693 DOI: 10.1016/0003-9969(91)90001-b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The cariogenicity and adhesion of six strains of Streptococcus vestibularis were compared with those of strains of Strep. salivarius. All strains of Strep. vestibularis produced low levels of caries, confined to the fissures, whereas the two strains of Strep. salivarius produced high levels of caries, with one strain producing approximal as well as fissure caries. The values for adhesion to saliva-coated hydroxyapatite of Strep. vestibularis in the absence (median 4.74%) and the presence (median 4.67%) of sucrose were not statistically different, nor did they differ significantly from those of Strep. salivarius. Strains of Strep. vestibularis were able to adhere to buccal epithelial cells (median 1.19%) as well as could Strep. salivarius strain HB (1.65%). Neither sucrose nor saliva greatly aggregated the strains of either species. Strep. vestibularis did not adhere to hexadecane (median 18.5%) to the same extent as did Strep. salivarius strains (median 69%). There was a significant correlation between the adhesion in the presence and absence of sucrose (p less than 0.01). Strep. vestibularis strains could not coaggregate with either actinomycetes or Veillonella spp. whereas Strep. salivarius strains were able to coaggregate with Veillonella spp.
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Affiliation(s)
- M D Willcox
- Institute of Dental Research, Surry Hills, NSW, Australia
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26
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Ligtenberg AJ, Veerman EC, de Graaff J, Nieuw Amerongen AV. Saliva-induced aggregation of oral streptococci and the influence of blood group reactive substances. Arch Oral Biol 1990; 35 Suppl:141S-143S. [PMID: 2088217 DOI: 10.1016/0003-9969(90)90145-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Aggregation of strains of Streptococcus rattus, Strep. mutans and Strep. salivarius by saliva from individuals of blood groups A, B and O was investigated. Blood group A salivas had a significantly higher aggregation activity with Strep. rattus than blood group B salivas (P less than 0.05). However, Strep. mutans and Strep. salivarius were better aggregated by blood group B saliva and this was significant for Strep. mutans (P less than 0.05). For all three strains, the variance within blood group O was too large to give significant differences with either blood group A or B. The blood group A-specific carbohydrate, N-acetyl-D-galactosamine, inhibited aggregation of Strep. rattus, but not of the other strains. The blood group B-specific carbohydrate, D-galactose, inhibited aggregation of Strep. mutans but not of Strep. rattus or Strep. salivarius. L-Fucose, specific for blood group O failed to inhibit aggregation of any of the three strains. These findings suggest that blood group-specific substances may be involved in bacterial aggregation.
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Affiliation(s)
- A J Ligtenberg
- Department of Oral Biochemistry, Vrije Universiteit, Amsterdam, The Netherlands
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27
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Pratt-Terpstra I, Weerkamp A, Busscher H. Microbial factors in a thermodynamic approach of oral streptococcal adhesion to solid substrata. J Colloid Interface Sci 1989. [DOI: 10.1016/0021-9797(89)90471-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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28
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Dainty RH, Edwards RA, Hibbard CM, Marnewick JJ. Volatile compounds associated with microbial growth on normal and high pH beef stored at chill temperatures. THE JOURNAL OF APPLIED BACTERIOLOGY 1989; 66:281-9. [PMID: 2753835 DOI: 10.1111/j.1365-2672.1989.tb02480.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Volatile compounds produced by Pseudomonas fragi and mixed, natural floras on beef of normal pH (5.5-5.8; glucose greater than 1500 micrograms/g) and high pH (6.3-6.8; glucose less than 10 micrograms/g) included a range of alkyl esters and a number of sulphur-containing compounds including dimethylsulphide but not hydrogen sulphide. Production of the last was a property common to the other Gram-negative organisms tested viz. Hafnia alvei, Enterobacter agglomerans, Serratia liquefaciens, Alteromonas putrefaciens and Aeromonas hydrophila, all of which produced similar off-odours and, with the exception of E. agglomerans, 'greening' on high pH meat. Serratia liquefaciens also produced greening of normal pH meat. Acetoin and diacetyl were major end products of Brochothrix thermosphacta but the related 2,3-butanediol was formed only on normal pH meat. The Enterobacteriaceae produced the same compounds but only on normal pH meat and together with Br. thermosphacta were probable sources of these compounds and of the free and esterified branched-chain alcohols detected in the naturally contaminated samples.
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Affiliation(s)
- R H Dainty
- Institute of Food Research, Bristol Laboratory, Langford, UK
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29
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Kolenbrander PE. Surface recognition among oral bacteria: multigeneric coaggregations and their mediators. Crit Rev Microbiol 1989; 17:137-59. [PMID: 2692602 DOI: 10.3109/10408418909105746] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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30
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Pratt-Terpstra IH, Weerkamp AH, Busscher HJ. On a relation between interfacial free energy-dependent and noninterfacial free energy-dependent adherence of oral streptococci to solid substrata. Curr Microbiol 1988. [DOI: 10.1007/bf01568537] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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31
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Harty DW, Handley PS. Fermentation products, amino acid utilization, maintenance energies and growth yields for the fibrillar Streptococcus salivarius HB and a non-fibrillar mutant HB-B grown in continuous culture under glucose limitation. THE JOURNAL OF APPLIED BACTERIOLOGY 1988; 65:143-52. [PMID: 3204071 DOI: 10.1111/j.1365-2672.1988.tb01502.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The fibrillar strain Streptococcus salivarius HB and a non-fibrillar mutant, strain HB-B, were grown in a defined medium under glucose limitation in a chemostat. Fermentation balances were produced for both strains in batch culture and at growth rates between 0.1/h and 1.1/h. In batch culture both strains fermented glucose to lactate, but in continuous culture glucose was fermented to formate, acetate and ethanol with increasing amounts of lactate as the growth rate was increased. Lactate never became the major fermentation product even at the highest growth rate. Amino acid analysis showed that only lysine was more than 50% utilized, while proline and tyrosine showed net production. The non-fibrillar strain HB-B showed, in general, a reduced utilization of amino acids compared with the fibrillar strain HB. Calculated growth yields and maintenance energies for the two strains showed that there was a reduction in the true growth yield and the maintenance energy coefficient of the non-fibrillar strain HB-B when compared with the fibrillar strain HB. The increase in the maintenance energy of the fibrillar strain HB (1.382 mmol/g/h) when compared with the non-fibrillar strain HB-B (0.546 mmol/g/h) of 153% is proposed to be the energy required for the maintenance of the fibrillar surface of the cell.
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Affiliation(s)
- D W Harty
- Department of Cell and Structural Biology, Medical School, Manchester University, UK
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32
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van der Mei HC, Léonard AJ, Weerkamp AH, Rouxhet PG, Busscher HJ. Surface properties of Streptococcus salivarius HB and nonfibrillar mutants: measurement of zeta potential and elemental composition with X-ray photoelectron spectroscopy. J Bacteriol 1988; 170:2462-6. [PMID: 3372474 PMCID: PMC211156 DOI: 10.1128/jb.170.6.2462-2466.1988] [Citation(s) in RCA: 69] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
To characterize the functional cell surface, the zeta potentials and elemental surface composition of Streptococcus salivarius HB and a range of mutants with known molecular surface structures were determined. Zeta potentials of fully hydrated cells were measured as a function of pH in dilute potassium phosphate solutions, yielding isoelectric points of the strains. Elemental composition (O, C, N, and P) of the outer 2 to 5 nm of the freeze-dried cell surfaces were measured by X-ray photoelectron spectroscopy. An increasing loss of proteinaceous fibrillar surface antigens of the mutants was found to be accompanied by a progressive decrease in the N/C ratio from 0.104 in the parent strain HB to 0.053 in mutant HBC12. Simultaneously, the value of the isoelectric point shifted from 3.0 to 1.3. In a previous study (A.H. Weerkamp, H.C. van der Mei, and J. W. Slot, Infect. Immun. 55:438-455, 1987) on the cell surfaces of the same strains, it was shown that removal of fibrils led to increased exposure of (lipo)teichoic acid at the surface, which explains the low isoelectric point caused by the low pKa of the phosphate groups.
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Crowley PJ, Fischlschweiger W, Coleman SE, Bleiweis AS. Intergeneric bacterial coaggregations involving mutans streptococci and oral actinomyces. Infect Immun 1987; 55:2695-700. [PMID: 3117688 PMCID: PMC259963 DOI: 10.1128/iai.55.11.2695-2700.1987] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Mutans streptococci (MS) representing eight different serotypes were tested for their ability to coaggregate in vitro with oral actinomyces and other streptococcal species. Of the mutans streptococci tested, only strains of S. cricetus (formerly S. mutans serotype a) displayed pronounced coaggregations and only with certain strains of actinomyces. S. cricetus coaggregated, by lactose nonreversible mechanisms, with serotype 4 Actinomyces naeslundii WVU963 and WVU924 and with serotype 2 Actinomyces odontolyticus WVU758. The first pair was disaggregated by protein denaturants (e.g., sodium dodecyl sulfate and urea) and EDTA. This coaggregation was inhibited when the streptococcal, but not the actinomyces, partner was pretreated with either heat or protease, suggesting the presence of a protein mediator on only the streptococcal cell surface. The S. cricetus-A. odontolyticus coaggregation appeared to involve protein components on each cell, as shown by the lack of coaggregation after pretreatment of either cell type with heat or proteases. This coaggregation was also reversed by sodium dodecyl sulfate and urea, as well as by sodium deoxycholate, but not by EDTA. The data indicate that different mechanisms may be involved in each of these coaggregations.
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Affiliation(s)
- P J Crowley
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville 32610
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Sommer P, Bruyère T, Ogier JA, Garnier JM, Jeltsch JM, Klein JP. Cloning of the saliva-interacting protein gene from Streptococcus mutans. J Bacteriol 1987; 169:5167-73. [PMID: 2959652 PMCID: PMC213922 DOI: 10.1128/jb.169.11.5167-5173.1987] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Genomic libraries from Streptococcus mutans OMZ175 were constructed in bacteriophage vectors. DNA fragments 1 to 2 kilobases in length were cloned in expression vector lambda gt11. S. mutans DNA fragments 15 to 20 kilobases in length were inserted in the BamHI site of phage EMBL3. Rabbit antiserum raised against an S. mutans saliva-interacting protein with a molecular weight of 74,000, designated 74K SR, was used to screen the lambda gt11 library. A recombinant phage carrying an S. mutans DNA sequence of 1.45 kilobases, lambda SmAD2, was detected and isolated. This fragment, named SmAD2, was used to construct the recombinant expression plasmid pSAD2-4 which encoded for the expression of a 60,000-molecular-weight protein controlled by the beta-galactosidase promoter from plasmid pUC8. The SmAD2 fragment and polyclonal anti-74K SR antibodies were used to screen the EMBL3 library. A total coincidence between the screening with antibodies and the DNA probe was observed, and two phages, lambda SmAD9 and lambda SmAD10, were isolated. They contained a common S. mutans DNA sequence of about 11.8 kilobases and coded for a protein with a molecular weight of about 195,000, which comigrated with a protein of an S. mutans cell wall extract. The expressed protein was purified, and a very strong relationship with the S. mutans 74K SR protein was found by competitive enzyme-linked immunosorbent assay. Thus, cloning of the 74K SR gene allowed us to demonstrate that the saliva receptor appears to be a part of an S. mutans precursor molecule with a molecular mass of 195,000 daltons.
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Affiliation(s)
- P Sommer
- Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Strasbourg, France
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35
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Weerkamp AH, van der Mei HC, Slot JW. Relationship of cell surface morphology and composition of Streptococcus salivarius K+ to adherence and hydrophobicity. Infect Immun 1987; 55:438-45. [PMID: 3804445 PMCID: PMC260347 DOI: 10.1128/iai.55.2.438-445.1987] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The cell surfaces of a range of variants of Streptococcus salivarius HB, altered in cell wall antigen composition, were compared with those of the parent with respect to adherence, ability to adsorb to hexadecane, morphology, and exposure of lipoteichoic acid (LTA). Adherence to host surfaces was measured by using both saliva-coated hydroxyapatite beads and tissue-cultured HeLa cells, and interbacterial adherence was measured by using Veillonella alcalescens V1 cells. Progressive loss of the protease-sensitive fibril classes was generally associated with decreasing ability to adsorb to hexadecane. However, increased exposure of protein antigen C (AgC) increased the apparent hydrophobicity of the cell. This correlated with the finding that AgC was the most hydrophobic of the solubilized fibrillar cell wall antigens. Collectively, this demonstrates that adsorption to hydrophobic ligands is directly related to the density of the fibrillar layer on the cells and the properties and surface exposure of specific fibril classes. The involvement of hydrophobic interactions in AgC-associated attachment was suggested by its sensitivity to low levels of the hydrophobic bond-breaking agent tetramethyl urea, although the reduction was not to the level of adherence observed with strains lacking AgC. However, hydrophobicity was less essential to other adherence reactions. Circumstantial evidence, including immunoelectron microscopy, showing that LTA was virtually absent from the fibrillar layer, whole-cell enzyme-linked immunosorbent assay, suggesting that surface exposure of LTA related inversely to the density of the fibrillar layer, and agarose gel electrophoresis, showing that LTA was not specifically associated with protein fibrillar antigens, strongly suggested that LTA does not confer hydrophobic properties to these cells and is not involved in adherence reactions associated with the cell wall protein antigens.
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36
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Mei HC, Weerkamp AH, Busscher HJ. Physico-chemical surface characteristics and adhesive properties ofStreptococcus salivariusstrains with defined cell surface structures. FEMS Microbiol Lett 1987. [DOI: 10.1111/j.1574-6968.1987.tb01974.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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37
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Wachsmann D, Klein JP, Scholler M, Ogier J, Ackermans F, Frank RM. Serum and salivary antibody responses in rats orally immunized with Streptococcus mutans carbohydrate protein conjugate associated with liposomes. Infect Immun 1986; 52:408-13. [PMID: 3699888 PMCID: PMC261014 DOI: 10.1128/iai.52.2.408-413.1986] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In this study we describe the preparation of a Streptococcus mutans vaccine consisting of a purified polysaccharide antigen, derived from S. mutans OMZ175 serotype f, covalently coupled through reductive amination to a previously isolated 74,000-molecular-weight (74K) cell wall protein which interacts with saliva proteins (74K-SR). We also investigated the local and systemic immune response to the poly-74K-SR conjugate after oral administration of the conjugate associated with liposomes. Intragastric administration of liposome-associated poly-74K-SR conjugate in rats produced a local immunoglobulin A (IgA) response directed against the polysaccharide and the cell surface protein, whereas liposome-associated polysaccharide was unable to induce any detectable local IgA response. The antigenicity of the polysaccharide in the conjugate was not affected by the coupling reaction, while that of the cell surface protein was reduced. We showed that the immunogenicity of S. mutans polysaccharide could be improved by chemical coupling with a carrier cell surface protein. If such a conjugate were orally administered with liposomes it could constitute a potential vaccine against dental caries.
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Weerkamp AH, van der Mei HC, Liem RS. Structural properties of fibrillar proteins isolated from the cell surface and cytoplasm of Streptococcus salivarius (K+) cells and nonadhesive mutants. J Bacteriol 1986; 165:756-62. [PMID: 3949715 PMCID: PMC214493 DOI: 10.1128/jb.165.3.756-762.1986] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Most Streptococcus salivarius (K+) cells contain two protein antigens with different adhesive functions. The subcellular distribution and some structural properties of purified proteins were studied. Antigen B (AgB), a protein involved in interbacterial coaggregation with gram-negative bacteria, was present in the cell wall fraction only of the wild-type strain and was absent from the cells of a nonadhesive mutant. Antigen C (AgC), a glycoprotein involved in host-associated adhesive functions, was predominantly associated with the cell wall of the wild-type strain (AgCw), but accumulated in high amounts in the cytoplasmic fraction (AgCin) of mutants lacking the wall-associated form. AgB, AgCw, and AgCin had molecular weights of 380,000, 250,000 to 320,000, and 488,000, respectively, upon gel electrophoresis under nondenaturing conditions. In the presence of sodium dodecyl sulfate and beta-mercaptoethanol the molecular weights were only slightly lower, suggesting that the free, isolated molecules exist as monomers under native conditions. AgCin readily stained with periodate-Schiff reagent, indicating a significant content of carbohydrate, similar to AgCw. Circular dichroism spectra showed that about 45% of the amino acids of AgCw were involved in alpha-helical coiled structures. AgB had a significantly lower proportion of ordered coiled structure. Electron microscopic observations of low-angle-shadowed preparations of purified antigens showed that they were flexible, thin rods with thickened or globular ends. Measurements corrected for shadow thickness showed lengths of 184 nm (AgB), 112 nm (AgCin), and 87 nm (AgCw). Treatment of AgCw with protease destroyed the fibrillar core, but seemed not to affect the globular ends. Comparison of the results with the localization of the antigens in wild-type and specific mutant strains suggested that each antigen molecule may represent a single, characteristic surface fibril with a specific adhesive capacity.
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Negative staining and immunoelectron microscopy of adhesion-deficient mutants of Streptococcus salivarius reveal that the adhesive protein antigens are separate classes of cell surface fibril. J Bacteriol 1986; 165:746-55. [PMID: 2419308 PMCID: PMC214492 DOI: 10.1128/jb.165.3.746-755.1986] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The subcellular distribution of the cell wall-associated protein antigens of Streptococcus salivarius HB, which are involved in specific adhesive properties of the cells, was studied. Mutants which had lost the adhesive properties and lacked the antigens at the cell surface were compared with the parent strain. Immunoelectron microscopy of cryosections of cells labeled with affinity-purified, specific antisera and colloidal gold-protein A complexes was used to locate the antigens. Antigen C (AgC), a glycoprotein involved in attachment to host surfaces, was mainly located in the fibrillar layer outside the cell wall. A smaller amount of label was also found throughout the cytoplasmic area in the form of small clusters of gold particles, which suggests a macromolecular association. Mutant HB-7, which lacks the wall-associated AgC, accumulated AgC reactivity intracellularly. Intracellular AgC was often found associated with isolated areas of increased electron density, but sometimes seemed to fill the entire interior of the cell. Antigen B (AgB), a protein responsible for interbacterial coaggregation, was also located in the fibrillar layer, although its distribution differed from that of the wall-associated AgC since AgB was found predominantly in the peripheral areas. A very small amount of label was also found in the cytoplasmic area as discrete gold particles. Mutant HB-V5, which lacks wall-associated AgB, was not labeled in the fibrillar coat, but showed the same weak intracellular label as the parent strain. Immunolabeling with serum against AgD, another wall-associated protein but of unknown function, demonstrated its presence in the fibrillar layer of strain HB. Negatively stained preparations of whole cells of wild-type S. salivarius and mutants that had lost wall-associated AgB or AgC revealed that two classes of short fibrils are carried on the cell surface at the same time. AgB and AgC are probably located on separate classes of short, protease-sensitive fibrils 91 and 72 nm in length, respectively. A third class of only very sparsely distributed short fibrils (63 nm) was observed on mutant HB-V51, which lacks both wall-associated AgB and AgC antigens. The identity of these fibrils and whether they are present on the wild type are not clear. The function of long, protease-resistant fibrils of 178 nm, which are also present on the wild-type strain, remains unknown.
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Weerkamp AH, Handley PS. The growth rate regulates the composition and density of the fibrillar coat on the surface ofStreptococcus salivariusK+cells. FEMS Microbiol Lett 1986. [DOI: 10.1111/j.1574-6968.1986.tb01267.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Kagermeier A, London J. Identification and preliminary characterization of a lectinlike protein from Capnocytophaga gingivalis (emended). Infect Immun 1986; 51:490-4. [PMID: 3943898 PMCID: PMC262361 DOI: 10.1128/iai.51.2.490-494.1986] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A polypeptide believed to be the monomeric form of the lectin responsible for the coaggregation of Capnocytophaga gingivalis (emended) and Actinomyces israelii has been identified. Denaturing polyacrylamide gel electrophoresis and immunoblot analyses were used to distinguish the protein from other proteins in the outer membrane of C. gingivalis. The subunit of the putative lectin has a pI of 8.6 and a molecular weight of 155,000.
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Okahashi N, Koga T, Hamada S. Purification and immunochemical properties of a protein antigen from serotype g Streptococcus mutans. Microbiol Immunol 1986; 30:35-47. [PMID: 3084923 DOI: 10.1111/j.1348-0421.1986.tb00919.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A proteinaceous antigen (PAg) was purified from the culture supernatant of Streptococcus mutans 6715 (serotype g) by ultrafiltration, ammonium sulfate precipitation, DEAE-Sephacel ion-exchange chromatography, Phenyl-Sepharose CL-4B hydrophobic chromatography, and subsequent Sephacryl S-300 gel filtration. A yield of 0.1 mg of PAg was obtained from a liter of culture supernatant. The isoelectric point and molecular weight of PAg were pH 4.6 and 210,000, respectively. It contained 35% sugar, which was identified as glucose by gas-liquid chromatography. Amino acid analysis revealed that PAg contains 28% acidic and 11% basic amino acid residues. PAg retained its antigenicity after heating at 80 C for 10 min in deionized water, or after treatment with 0.1 M HC1 or 0.1 M NaOH at 37 C for 1 hr. Immunodiffusion and immunoelectrophoresis analyses revealed that PAg is serologically distinct from other cell-surface antigens such as serotype-specific polysaccharide and lipoteichoic acid. A cross-reaction between PAg and a protein antigen similarly prepared from serotype c S. mutans was observed in immunodiffusion tests.
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Morris EJ, Ganeshkumar N, McBride BC. Cell surface components of Streptococcus sanguis: relationship to aggregation, adherence, and hydrophobicity. J Bacteriol 1985; 164:255-62. [PMID: 4044521 PMCID: PMC214237 DOI: 10.1128/jb.164.1.255-262.1985] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cell surfaces of aggregation, adherence, and hydrophilic variants of Streptococcus sanguis were compared with cell surfaces of the parent strain with regard to their protein and antigenic constituents. Cell surface molecules were released by digestion with mutanolysin. Extraction with sodium dodecyl sulfate (SDS) urea, lithium diiodosalicylate, and boiling water did not solubilize any material which stained with AgNO3 in an SDS-polyacrylamide gel electrophoresis gel. The parent organism S. sanguis 12, which aggregates in saliva, adheres to saliva-coated hydroxyapatite and is hydrophobic, was found to possess a prominently staining 160,000 molecular weight (MW) protein. This protein was almost completely absent from strain 12na, a hydrophobic nonaggregating variant, and was completely absent from the hydrophilic nonaggregating strain 12L. Trypsinization of strain 12 resulted in the coincident loss of the 160,000-MW protein and the ability to aggregate in saliva. Trypsin treatment reduced but did not eliminate the hydrophobic character of the cells. Boiling destroyed their ability to aggregate, but did not alter their hydrophobicity. Cell wall digests of strain 12 contained a number of proteins which were absent from strains 12na and 12L. Mutanolysin digests of cell walls of the hydrophilic strains contained almost no material that was visible in a silver-stained SDS-polyacrylamide gel electrophoresis gel. Culture supernatants contained a number of proteins which were immunologically cross-reactive with cell surface proteins. The hydrophilic organisms released a number of 60,000- to 90,000-MW proteins not seen in culture supernatants from the parent strain.
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Ackermans F, Klein JP, Ogier J, Bazin H, Cormont F, Frank RM. Purification and characterization of a saliva-interacting cell-wall protein from Streptococcus mutans serotype f by using monoclonal-antibody immunoaffinity chromatography. Biochem J 1985; 228:211-7. [PMID: 3890841 PMCID: PMC1144971 DOI: 10.1042/bj2280211] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A rat monoclonal antibody, LO SM2, of the immunoglobulin M class, specific for a saliva receptor (SR) from Streptococcus mutans serotype f, was able to precipitate the SR from crude cell-wall-associated antigens (WEA) of this bacteria in presence of a detergent mixture. We have then used the technique of monoclonal-antibody immunoaffinity chromatography to purify the S. mutans SR. Pure SR was obtained from a crude WEA fraction with a single chromatographic step. The active SR could be eluted from the column in a highly purified form with 0.2 M-glycine/HC1, pH 2.8. The final yield was about 32% in terms of binding activity. Characterization of the SR by crossed immunoelectrophoresis, sodium dodecyl sulphate- or 4-30%-native-gradient-polyacrylamide-gel electrophoresis showed that the receptor is a single polypeptide chain of Mr approx. 74000. Native or denaturated forms of the SR adsorbed on to a solid support, such as nitrocellulose, are recognized by monoclonal antibody LO SM2, and both forms are still able to bind the ligand, saliva.
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Weerkamp AH, Mei HC, Liem RS. Adhesive cell wall-associated glycoprotein ofStreptococcus salivarius(K+) is a cell surface fibril. FEMS Microbiol Lett 1984. [DOI: 10.1111/j.1574-6968.1984.tb01054.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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McBride BC, Song M, Krasse B, Olsson J. Biochemical and immunological differences between hydrophobic and hydrophilic strains of Streptococcus mutans. Infect Immun 1984; 44:68-75. [PMID: 6706407 PMCID: PMC263470 DOI: 10.1128/iai.44.1.68-75.1984] [Citation(s) in RCA: 99] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Hydrophobic strains of Streptococcus mutans were compared with paired variants showing reduced hydrophobicity. Extracts of hydrophobic cells contained a number of high-molecular-weight proteins which were not present on cells with decreased hydrophobicity. The proteins were found in purified cell walls, suggesting that they are located on the bacterial surface. Trypsin treatment of whole cells destroyed the proteins and reduced the hydrophobicity. Chemical analysis did not reveal any marked differences in the proportion of cell wall constituents. The amino acid compositions and lipoteichoic acid contents of hydrophobic and hydrophilic cell walls were similar. Culture supernatants from the hydrophilic variants contained high-molecular-weight proteins similar to those extracted from the cell walls of the hydrophobic parent strains, indicating that the variants were impaired in their ability to incorporate the hydrophobicity-associated proteins into the cell wall. The dominant protein had a molecular weight of 190,000, similar to that of antigen I/II (B) of S. mutans.
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Handley PS, Carter PL, Fielding J. Streptococcus salivarius strains carry either fibrils or fimbriae on the cell surface. J Bacteriol 1984; 157:64-72. [PMID: 6197404 PMCID: PMC215130 DOI: 10.1128/jb.157.1.64-72.1984] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Strains of Streptococcus salivarius were screened by negative staining for the presence of surface structures. Two structural subgroups were found, carrying either fibrils or fimbriae, projecting from the cell surface. Eight strains carried a very dense peritrichous array of fibrils of two distinct lengths. Long fibrils had an average length of 175 nm, and short fibrils had an average length of 95 nm. Two strains carried only long fibrils, one strain carried only short fibrils, and another strain carried a lateral tuft of very prominent fibrils of two lengths, with a fibrillar fuzz covering the remainder of the cell surface. In all the strains in which they were present, the long fibrils were unaffected by protease or trypsin treatment. In contrast, the short fibrils were completely digested by protease and partially removed by trypsin. Neither long nor short fibrils were affected structurally by mild pepsin digestion or by lipase. The Lancefield extraction procedure removed both long and short fibrils. These twelve fibrillar strains were therefore divisible into four structural subgroups. Extracts of all the fibrillar strains reacted with group K antiserum. The second main structural subgroup consisted of nine strains of S. salivarius, all of which carried morphologically identical, flexible fimbriae arranged peritrichously over the cell surface. The fimbriae were structurally distinct from fibrils and measured 0.5 to 1.0 micron long and 3 to 4 nm wide, with an irregular outline and no obvious substructure. There was no obvious reduction in the number of fimbriae after protease or trypsin treatment. Extracts of the fimbriated strains did not react with the group K antiserum. The two serological and structural subgroups could also be distinguished by colony morphology.
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