Nanomechanical properties of glucans and associated cell-surface adhesion of Streptococcus mutans probed by atomic force microscopy under in situ conditions

Cross, Sarah E.; Kreth, Jens; Zhu, Lin; Sullivan, Richard; Shi, Wenyuan; Qi, Fengxia; Gimzewski, James K.

doi:10.1099/mic.0.2007/007625-0

Cited by 76 publications

(93 citation statements)

References 38 publications

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“…The frequency of these retraction events increases as the SCEB matures, as summarised in Table 1. Similar multiple stepped events have been reported using AFM to map the positions of polysaccharides on the surface of viable yeast cells [16] and in the study of glucan polymers in Streptococcus mutans [37]. It could be postulated that these retraction events are either unfolding of polysaccharide moieties [37][38], unfolding of proteins contacted by the AFM tip [39], or successive release of multiple molecules connecting the biofilm and AFM tip [16,37].…”

Section: Individual Measurementssupporting

confidence: 60%

Characterisation of spin coated engineered Escherichia coli biofilms using atomic force microscopy

Tsoligkas

Bowen

Winn

et al. 2012

Colloids and Surfaces B: Biointerfaces

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The ability of biofilms to withstand chemical and physical extremes gives them the potential to be developed as robust biocatalysts. Critical to this issue is their capacity to withstand the physical environment within a bioreactor; in order to assess this capability knowledge of their surface properties and adhesive strength is required. Novel atomic force microscopy experiments conducted under growth conditions (30 o C) were used to characterise Escherichia coli biofilms, which were generated by a recently developed spin-coating method onto a poly-L-lysine coated glass substrate. High-resolution topographical images were obtained throughout the course of biofilm development, quantifying the tip-cell interaction force during the 10 day maturation process. Strikingly, the adhesion force between the Si AFM tip and the biofilm surface increased from 0.8 nN to 40 nN within 3 days. This was most likely due to the production of extracellular polymer substance (EPS), over the maturation period, which was also observed by electron microscopy. At later stages of maturation, multiple retraction events were also identified corresponding to biofilm surface features thought to be EPS components. The spin coated biofilms were shown to have stronger surface adhesion than an equivalent conventionally grown biofilm on the same glass substrate.

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Section: Individual Measurementssupporting

confidence: 60%

Characterisation of spin coated engineered Escherichia coli biofilms using atomic force microscopy

Tsoligkas

Bowen

Winn

et al. 2012

Colloids and Surfaces B: Biointerfaces

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“…mutans cells can attach initially to saliva-coated surfaces (albeit in low numbers) through sucrose-independent mechanisms mediated primarily by lectin-like interactions between specific pellicle proteins (e.g., agglutinins) and adhesins (e.g., P1) present on the bacterial cell surface (15). In contrast, this bacterium binds avidly to glucan-coated surfaces, particularly those synthesized in situ by GtfB and GtfC, in larger numbers and with greater adhesion strength than it binds to uncoated or saliva-coated apatitic surfaces (8,27,39). Moreover, S. mutans, alone or mixed with other species, can develop into microcolonies only when sucrose is available (26,50), suggesting a potential role of Gtfs and glucans in the formation and establishment of structured microcolonies.…”

Section: Resultsmentioning

confidence: 97%

“…do not produce glucans unless Gtfs are adsorbed on their surfaces (33,46). The glucans synthesized in situ provide binding sites for colonization and accumulation of S. mutans on the apatitic surface and for binding to each other through interactions with several membrane-associated glucan-binding proteins and surface glucans (8,39,47). The exopolymers also contribute to the bulk and physical integrity and stability of the biofilm matrix (for a review, see reference 36).…”

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confidence: 99%

Exopolysaccharides Produced by Streptococcus mutans Glucosyltransferases Modulate the Establishment of Microcolonies within Multispecies Biofilms

et al. 2010

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Streptococcus mutans is a key contributor to the formation of the extracellular polysaccharide (EPS) matrix in dental biofilms. The exopolysaccharides, which are mostly glucans synthesized by streptococcal glucosyltransferases (Gtfs), provide binding sites that promote accumulation of microorganisms on the tooth surface and further establishment of pathogenic biofilms. This study explored (i) the role of S. mutans Gtfs in the development of the EPS matrix and microcolonies in biofilms, (ii) the influence of exopolysaccharides on formation of microcolonies, and (iii) establishment of S. mutans in a multispecies biofilm in vitro using a novel fluorescence labeling technique. Our data show that the ability of S. mutans strains defective in the gtfB gene or the gtfB and gtfC genes to form microcolonies on saliva-coated hydroxyapatite surfaces was markedly disrupted. However, deletion of both gtfB (associated with insoluble glucan synthesis) and gtfC (associated with insoluble and soluble glucan synthesis) is required for the maximum reduction in EPS matrix and biofilm formation. S. mutans grown with sucrose in the presence of Streptococcus oralis and Actinomyces naeslundii steadily formed exopolysaccharides, which allowed the initial clustering of bacterial cells and further development into highly structured microcolonies. Concomitantly, S. mutans became the major species in the mature biofilm. Neither the EPS matrix nor microcolonies were formed in the presence of glucose in the multispecies biofilm. Our data show that GtfB and GtfC are essential for establishment of the EPS matrix, but GtfB appears to be responsible for formation of microcolonies by S. mutans; these Gtf-mediated processes may enhance the competitiveness of S. mutans in the multispecies environment in biofilms on tooth surfaces.Oral diseases related to dental biofilms afflict the majority of the world's population, and dental caries is still the single most prevalent and costly oral infectious disease (12, 32). Dental caries results from the interaction of specific bacteria with constituents of the diet within a biofilm formed on the tooth surface known as plaque (5,36). Streptococcus mutans is a key contributor to the formation of biofilms associated with dental caries disease, although other microorganisms may also be involved (3); S. mutans (i) effectively utilizes dietary sucrose (and possibly starch) to rapidly synthesize exopolysaccharides (EPS) using glucosyltransferases and a fructosyltransferase that adsorb to surfaces, (ii) adheres tenaciously to glucan-coated surfaces, and (iii) is acidogenic and acid tolerant (5, 30).In general, biofilms develop after initial attachment of microbes to a surface, followed by formation of highly structured cell clusters (or microcolonies) and further development and stabilization of the microcolonies, which are in a complex extracellular matrix (6, 49). The majority of biofilm matrices contain exopolysaccharides, and dental biofilms are no exception; up to 40% of the dry weight of dental plaque is compos...

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“…mutans is a biofilm-forming facultative anaerobic bacterium that produces three glucosyltransferase enzymes to synthesize glucans from dietary sugar (27)(28)(29). Glucans are sticky polymers that allow the cells to attach to the tooth surface and form an extracellular matrix that protects it from host defenses and mechanical removal (30,31). Once S. mutans attaches to the tooth surface, organic acids, which are produced as metabolic by-products, become concentrated within the extracellular matrix and cause a drop in pH from neutral to 5 or below.…”

mentioning

confidence: 99%

Salivary Mucins Protect Surfaces from Colonization by Cariogenic Bacteria

Frenkel

Ribbeck

2015

Appl Environ Microbiol

111

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bUnderstanding how the body's natural defenses function to protect the oral cavity from the myriad of bacteria that colonize its surfaces is an ongoing topic of research that can lead to breakthroughs in treatment and prevention. One key defense mechanism on all moist epithelial linings, such as the mouth, gastrointestinal tract, and lungs, is a layer of thick, well-hydrated mucus. The main gel-forming components of mucus are mucins, large glycoproteins that play a key role in host defense. This study focuses on elucidating the connection between MUC5B salivary mucins and dental caries, one of the most common oral diseases. Dental caries is predominantly caused by Streptococcus mutans attachment and biofilm formation on the tooth surface. Once S. mutans attaches to the tooth, it produces organic acids as metabolic by-products that dissolve tooth enamel, leading to cavity formation. We utilize CFU counts and fluorescence microscopy to quantitatively show that S. mutans attachment and biofilm formation are most robust in the presence of sucrose and that aqueous solutions of purified human MUC5B protect surfaces by acting as an antibiofouling agent in the presence of sucrose. In addition, we find that MUC5B does not alter S. mutans growth and decreases surface attachment and biofilm formation by maintaining S. mutans in the planktonic form. These insights point to the importance of salivary mucins in oral health and lead to a better understanding of how MUC5B could play a role in cavity prevention or diagnosis. One of the body's key defense mechanisms on wet epithelial linings, such as the mouth, gastrointestinal tract, and lungs, is a layer of thick, well-hydrated mucus. The viscoelastic properties of mucus are attributed to mucins, large glycoproteins that play a key role in host defense and maintaining a healthy microbial environment (1-3). Defects in mucin production can lead to diseases such as ulcerative colitis when mucins are underproduced or cystic fibrosis and asthma when mucins are overproduced (4-6). In addition, studies have shown that mucins can interact with microbes, such as Helicobacter pylori, Haemophilus parainfluenzae, and human immunodeficiency virus (7-10). These diseases and microbial interactions highlight the necessity of mucins as one of the body's key natural defenses; however, few studies have focused specifically on the connection between MUC5B salivary mucins and oral diseases. This study fills this gap in understanding by exploring the connection between purified human MUC5B and the virulence of Streptococcus mutans, one of the main cavitycausing bacteria naturally found in the oral cavity (11). MUC7 is another salivary mucin, but MUC5B is the primary mucin component of the dental pellicle coating the soft and hard tissues in the oral cavity (12, 13). Importantly, the effects of MUC5B are characterized in a clinically relevant three-dimensional model that mimics the natural environment in the oral cavity; mucins are secreted into an aqueous phase as opposed to a two-dimensional surfac...

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Nanomechanical properties of glucans and associated cell-surface adhesion of Streptococcus mutans probed by atomic force microscopy under in situ conditions

Cited by 76 publications

References 38 publications

Characterisation of spin coated engineered Escherichia coli biofilms using atomic force microscopy

Characterisation of spin coated engineered Escherichia coli biofilms using atomic force microscopy

Exopolysaccharides Produced by Streptococcus mutans Glucosyltransferases Modulate the Establishment of Microcolonies within Multispecies Biofilms

Salivary Mucins Protect Surfaces from Colonization by Cariogenic Bacteria

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