Extracellular Polysaccharides Matrix — An Often Forgotten Virulence Factor in Oral Biofilm Research

Koo, Hyun; Xiao, Jin; Klein, Marlise I.

doi:10.4248/ijos.09086

Cited by 71 publications

(61 citation statements)

References 19 publications

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“…It is now appreciated that the formation and maintenance of a structured plaque biofilm critically depends upon the production of EPS, among which the glucan matrix occupies an important role [Cury et al, 1997;Koo et al, 2009;Nobbs et al, 2009]. Consistent with the fact that the glucan matrix is the primary component of the dental biofilm, deletion of rnc results in decreased exopolysaccharides, further resulting in suppression of EPS-sheltered matrix aggregation.…”

Section: The Weakened Biofilm Forming Ability Was Associated With a Rmentioning

confidence: 89%

The Regulator Gene rnc Is Closely Involved in Biofilm Formation in Streptococcus mutans

Mao

Lei

et al. 2018

Caries Res

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Streptococcus mutans is an important factor in the etiology and pathogenesis of dental caries, largely owing to its ability to form a stable biofilm. Previous animal studies have indicated that rnc could decrease the amount of sulcal caries, and that the downregulation of cariogenicity might be due to its capacity to disrupt biofilm formation. However, the biofunctions by which rnc is involved in biofilm formation remain to be elucidated. In this study, we further investigate the role of rnc based on the study of mature biofilm. Scanning electron microscopy and the crystal violet assay were used to detect the biofilm forming ability. The production and distribution of exopolysaccharides within biofilm was analyzed by exopolysaccharide staining. Gel permeation chromatography was used to perform molecular weight assessment. Its adhesion force was measured by atomic force microscopy. The expression of biofilm formation-associated genes was analyzed at the mRNA level by qPCR. Here, we found that rnc could occur and function in biofilm formation by assembling well-structured, exopolysaccharide-encased, stable biofilms in S. mutans. The weakened biofilm forming ability of rnc-deficient strains was associated with the reduction of exopolysaccharide production and bacterial adhesion. Over all, these data illustrate an interesting situation in which an unappreciated regulatory gene acquired for virulence, rnc, most likely has been coopted as a potential regulator of biofilm formation in S. mutans. Further characterization of rnc may lead to the identification of a possible pathogenic biofilm-specific treatment for dental caries.

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Section: The Weakened Biofilm Forming Ability Was Associated With a Rmentioning

confidence: 89%

The Regulator Gene rnc Is Closely Involved in Biofilm Formation in Streptococcus mutans

Mao

Lei

et al. 2018

Caries Res

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“…4,5 S. mutans are considered the most cariogenic microorganisms in dental biofilm due to their capacity to use dietary carbohydrates such as sucrose, to synthesize extracellular polysaccharides (EPS) and because of their acidogenic and aciduric properties. 4 EPS are important virulence factors of S. mutans because they promote bacterial adherence to the tooth surface, 6,7 contribute to the structural integrity of dental biofilms, 8,9 change the porosity of the biofilm 10 and consequently increase enamel demineralization. 11 Therefore, S. mutans biofilms have been used to evaluate their cariogenic properties due to difficulties of developing in vivo studies in controlled cariogenic situations.…”

Section: Introductionmentioning

confidence: 99%

S. mutans biofilm model to evaluate antimicrobial substances and enamel demineralization

2010

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The aim of this study was to validate a model of S. mutans biofilm formation, which simulated 'feast-famine' episodes of exposure to sucrose that occur in the oral cavity, showed dose-response susceptibility to antimicrobials and allowed the evaluation of substances with anticaries potential. S. mutans UA159 biofilms were grown for 5 days on bovine enamel slabs at 37°C, 10% CO 2 . To validate the model, the biofilms were treated 2x/day with chlorhexidine digluconate (CHX) at 0.012, 0.024 and 0.12% (concentration with recognized anti-plaque effect) and 0.05% NaF (concentration with recognized anti-caries effect). CHX showed dose-response effect decreasing biomass, bacterial viability and enamel demineralization (p < 0.05). Whereas, 0.05% NaF did not show antimicrobial effect but had similar effect to that of 0.12% CHX decreasing enamel demineralization (p < 0.05). The model developed has potential to evaluate the effect of substances on biofilm growth and on enamel demineralization.

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“…Particularly, greater attention has been given to S. mutans by proving it to be the main bacterium responsible for the synthesis of insoluble extracellular polymers using sucrose as a substrate [Koo et al, 2009]. Many laboratory studies have focused on the solitary role of S. mutans -only biofilms on dental caries.…”

mentioning

confidence: 99%

“…In addition to providing a frame for continuous bacterial growth [Koo et al, 2009], the presence of such insoluble polymers in biofilm matrix has been associated with increased caries activity [Mattos-Graner et al, 2000].…”

mentioning

confidence: 99%

A Defined-Multispecies Microbial Model for Studying Enamel Caries Development

et al. 2013

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The aims of this study were to describe and validate an in vitro multispecies microbial biofilm model for caries development by evaluating the effects of varying medium concentration of sucrose (0.5 and 1.0%) and fluoride (0.4, 0.8 and 1.0 ppm F) in study 1, and calcium (1.0 and 2.0 mM Ca) in study 2. Defined-multispecies biofilms, formed by Lactobacillus casei, Streptococcus mutans, S. salivarius and S. sanguinis, were grown on the surface of salivary-pellicle-coated enamel slabs, with known baseline surface hardness; growth medium was changed daily. Counts of viable cells on biofilms and the percentage of surface microhardness change (%SMC), lesion depth (LD) and integrated mineral loss (IML) on enamel slabs were assessed after 4 days of biofilm formation under the tested conditions. Counts of viable cells on biofilms were significantly affected by sucrose, fluoride and calcium concentrations (p < 0.05). There was a decrease in %SMC in response to increased fluoride and calcium concentrations (p < 0.001). Lower IML (p < 0.001) and LD (p < 0.05) were found in the presence of 0.8 and 1.0 ppm F. A negative correlation was found between the response variables (%SMC, LD and IML) and fluoride and calcium concentrations. The results suggest that the microbial caries model developed was able to show distinct levels of caries inhibition in response to fluoride and calcium concentrations, corroborating clinical observations. An effect of sucrose concentration on caries development was found only in the presence of the lowest fluoride concentration.

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Extracellular Polysaccharides Matrix — An Often Forgotten Virulence Factor in Oral Biofilm Research

Cited by 71 publications

References 19 publications

The Regulator Gene <b><i>rnc</i></b> Is Closely Involved in Biofilm Formation in <b><i>Streptococcus mutans</i></b>

The Regulator Gene <b><i>rnc</i></b> Is Closely Involved in Biofilm Formation in <b><i>Streptococcus mutans</i></b>

S. mutans biofilm model to evaluate antimicrobial substances and enamel demineralization

A Defined-Multispecies Microbial Model for Studying Enamel Caries Development

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