scholarly journals A Hypothetical Protein of Streptococcus mutans Is Critical for Biofilm Formation

2005 ◽  
Vol 73 (5) ◽  
pp. 3147-3151 ◽  
Author(s):  
Thomas A. Brown ◽  
Sang-Joon Ahn ◽  
Roslyn N. Frank ◽  
Yi-Ywan M. Chen ◽  
José A. Lemos ◽  
...  
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Signal Sequence ◽  
Hypothetical Protein ◽  
Repeated Sequences ◽  
Carbohydrate Source ◽  
Novel Therapeutics ◽  
Potential Target ◽  
Conserved Regions

ABSTRACT Inactivation of the Smu0630 gene of Streptococcus mutans resulted in dramatic decreases in biofilm formation, regardless of the carbohydrate source. The Smu0630 protein contained numerous interesting features, including a possible signal sequence and two conserved regions of repeated sequences. Smu0630 may represent a potential target for novel therapeutics.

scholarly journals The Effects of Surface Roughness of Composite Resin on Biofilm Formation of Streptococcus mutans in the Presence of Saliva

2012 ◽  
Vol 37 (5) ◽  
pp. 532-539 ◽  
Author(s):  
JW Park ◽  
CW Song ◽  
JH Jung ◽  
SJ Ahn ◽  
JL Ferracane
Keyword(s):  
Surface Roughness ◽  
Silicon Carbide ◽  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Composite Resin ◽  
Resin Composite ◽  
Fluid Phase ◽  
Confocal Laser ◽  
Carbohydrate Source ◽  
Effect Of Surface

SUMMARY The purpose of this study was to investigate the effects of surface roughness of resin composite on biofilm formation of Streptococcus mutans in the presence of saliva. To provide uniform surface roughness on composites, disks were prepared by curing composite against 400-grit silicon carbide paper (SR400), 800-grit silicon carbide paper (SR800), or a glass slide (SRGlass). The surface roughness was examined using confocal laser microscopy. For biofilm formation, S. mutans was grown for 24 hours with each disk in a biofilm medium with either glucose or sucrose in the presence of fluid-phase or surface-adsorbed saliva. The adherent bacteria were quantified via enumeration of the total viable counts of bacteria. Biofilms were examined using scanning electron microscopy. This study showed that SR400 had deeper and larger, but fewer depressions than SR800. Compared to SRGlass and SR800, biofilm formation was significantly increased on SR400. In addition, the differences in the effect of surface roughness on the amount of biofilm formation were not significantly influenced by either the presence of saliva or the carbohydrate source. Considering that similar differences in surface roughness were observed between SR400 and SR800 and between SR800 and SRGlass, this study suggests that surface topography (size and depth of depressions) may play a more important role than surface roughness in biofilm formation of S. mutans.

scholarly journals Pleiotropic Regulation of Virulence Genes in Streptococcus mutans by the Conserved Small Protein SprV

2017 ◽  
Vol 199 (8) ◽  
Author(s):  
Manoharan Shankar ◽  
Mohammad S. Hossain ◽  
Indranil Biswas
Keyword(s):  
Dental Caries ◽  
Streptococcus Mutans ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Normal Growth ◽  
Hypothetical Protein ◽  
Bacteriocin Production ◽  
Transcript Levels ◽  
Content Type ◽  
Tooth Surfaces

ABSTRACT Streptococcus mutans, an oral pathogen associated with dental caries, colonizes tooth surfaces as polymicrobial biofilms known as dental plaque. S. mutans expresses several virulence factors that allow the organism to tolerate environmental fluctuations and compete with other microorganisms. We recently identified a small hypothetical protein (90 amino acids) essential for the normal growth of the bacterium. Inactivation of the gene, SMU.2137, encoding this protein caused a significant growth defect and loss of various virulence-associated functions. An S. mutans strain lacking this gene was more sensitive to acid, temperature, osmotic, oxidative, and DNA damage-inducing stresses. In addition, we observed an altered protein profile and defects in biofilm formation, bacteriocin production, and natural competence development, possibly due to the fitness defect associated with SMU.2137 deletion. Transcriptome sequencing revealed that nearly 20% of the S. mutans genes were differentially expressed upon SMU.2137 deletion, thereby suggesting a pleiotropic effect. Therefore, we have renamed this hitherto uncharacterized gene as sprV (streptococcal pleiotropic regulator of virulence). The transcript levels of several relevant genes in the sprV mutant corroborated the phenotypes observed upon sprV deletion. Owing to its highly conserved nature, inactivation of the sprV ortholog in Streptococcus gordonii also resulted in poor growth and defective UV tolerance and competence development as in the case of S. mutans. Our experiments suggest that SprV is functionally distinct from its homologs identified by structure and sequence homology. Nonetheless, our current work is aimed at understanding the importance of SprV in the S. mutans biology. IMPORTANCE Streptococcus mutans employs several virulence factors and stress resistance mechanisms to colonize tooth surfaces and cause dental caries. Bacterial pathogenesis is generally controlled by regulators of fitness that are critical for successful disease establishment. Sometimes these regulators, which are potential targets for antimicrobials, are lost in the genomic context due to the lack of annotated homologs. This work outlines the regulatory impact of a small, highly conserved hypothetical protein, SprV, encoded by S. mutans. We show that SprV affects the transcript levels of various virulence factors required for normal growth, biofilm formation, stress tolerance, genetic competence, and bacteriocin production.

scholarly journals Effects of RelA on Key Virulence Properties of Planktonic and Biofilm Populations of Streptococcus mutans

2004 ◽  
Vol 72 (3) ◽  
pp. 1431-1440 ◽  
Author(s):  
José A. C. Lemos ◽  
Thomas A. Brown ◽  
Robert A. Burne
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Type Strain ◽  
Wild Type Strain ◽  
Stringent Response ◽  
Strain Differences ◽  
Acid Tolerance ◽  
Normal Growth ◽  
Wild Type ◽  
Carbohydrate Source

ABSTRACT Streptococcus mutans is a biofilm-forming bacterium that is adapted to tolerate rapid and dramatic fluctuations in nutrient availability, carbohydrate source, and pH in its natural environment, the human oral cavity. Dissecting the pathways used to form stable biofilms and to tolerate environmental stress is central to understanding the virulence of this organism. Here, we investigated the role of the S. mutans relA gene, which codes for a guanosine tetraphosphate and guanosine pentaphosphate [(p)ppGpp] synthetase/hydrolase, in biofilm formation and acid tolerance. Two mutants in which relA was insertionally inactivated or replaced by an antibiotic resistance determinant were constructed. Under normal growth and stress conditions, the mutants grew slower than the wild-type strain, although the final yields were similar. The mutants, which were still able to accumulate (p)ppGpp after the induction of a stringent response, showed significant reductions in biofilm formation on microtiter plates or hydroxylapatite disks. There was no difference in the sensitivities to acid killing of the parent and relA strains grown in planktonic cultures. However, when cells were grown in biofilms, the mutants became more acid resistant and could lower the pH through glycolysis faster and to a greater extent than the wild-type strain. Differences in acid resistance were not correlated with increases in F-ATPase activity, although bacterial sugar:phosphotransferase activity was elevated in the mutants. Expression of the luxS gene was increased as much as fivefold in the relA mutants, suggesting a link between AI-2 quorum sensing and the stringent response.

scholarly journals Influence of BrpA on Critical Virulence Attributes of Streptococcus mutans

2006 ◽  
Vol 188 (8) ◽  
pp. 2983-2992 ◽  
Author(s):  
Zezhang T. Wen ◽  
Henry V. Baker ◽  
Robert A. Burne
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Tooth Surface ◽  
Confocal Laser ◽  
Carbohydrate Source ◽  
Flow Cells ◽  
Forming Characteristics

ABSTRACT Streptococcus mutans, the primary etiological agent of human dental caries, has developed multiple mechanisms to colonize and form biofilms on the tooth surface. The brpA gene codes for a predicted surface-associated protein with apparent roles in biofilm formation, autolysis, and cell division. In this study, we used two models to further characterize the biofilm-forming characteristics of a BrpA-deficient mutant, strain TW14. Compared to those of the parent strain, UA159, TW14 formed long chains and sparse microcolonies on hydroxylapatite disks but failed to accumulate and form three-dimensional biofilms when grown on glucose as the carbohydrate source. The biofilm formation defect was also readily apparent by confocal laser scanning microscopy when flow cells were used to grow biofilms. When subjected to acid killing at pH 2.8 for 45 min, the survival rate of strain TW14 was more than 1 log lower than that of the wild-type strain. TW14 was at least 3 logs more susceptible to killing by 0.2% hydrogen peroxide than was UA159. The expression of more than 200 genes was found by microarray analysis to be altered in cells lacking BrpA (P < 0.01). These results suggest that the loss of BrpA can dramatically influence the transcriptome and significantly affects the regulation of acid and oxidative stress tolerance and biofilm formation in S. mutans, which are key virulence attributes of the organism.

scholarly journals Trigger Factor in Streptococcus mutans Is Involved in Stress Tolerance, Competence Development, and Biofilm Formation

2005 ◽  
Vol 73 (1) ◽  
pp. 219-225 ◽  
Author(s):  
Zezhang T. Wen ◽  
Prashanth Suntharaligham ◽  
Dennis G. Cvitkovitch ◽  
Robert A. Burne
Keyword(s):  
Stress Tolerance ◽  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Trigger Factor ◽  
Deficient Mutant ◽  
Carbohydrate Source ◽  
Oxidative Stresses ◽  
Parent Loss ◽  
Type Strains ◽  
And Oxidative Stress

ABSTRACT Trigger factor is a ribosome-associated peptidyl-prolyl cis/trans isomerase that is highly conserved in most bacteria. A gene, designated ropA, encoding an apparent trigger factor homologue, was identified in Streptococcus mutans, the primary etiological agent of human dental caries. Inactivation of ropA had no major impact on growth rate in planktonic cultures under the conditions tested, although the RopA-deficient mutant formed long chains in broth. Deficiency of RopA decreased tolerance to acid killing and to oxidative stresses induced by hydrogen peroxide and paraquat, and it reduced transformation efficiency about 200-fold. Addition of synthetic competence-stimulating peptide to the culture medium enhanced transformability of both the mutant and wild-type strains, although the ropA strain did not attain levels of competence observed for the parent. Loss of RopA decreased the capacity of S. mutans to form biofilms by over 80% when cultivated in glucose, but it increased biofilm formation by over 50% when sucrose was provided as the carbohydrate source. Western blot analysis revealed that the expression of glucosyltransferases B and D was lower in the RopA-deficient mutant. These results suggest that RopA is a key regulator of acid and oxidative stress tolerance, genetic competence, and biofilm formation, all critical virulence properties of S. mutans.

scholarly journals Multiple Streptococcus mutans Genes Are Involved in Biofilm Formation

2002 ◽  
Vol 68 (12) ◽  
pp. 6283-6291 ◽  
Author(s):  
Akihiro Yoshida ◽  
Howard K. Kuramitsu
Keyword(s):  
Streptococcus Mutans ◽  
Dental Plaque ◽  
Biofilm Formation ◽  
Regulatory Gene ◽  
Hypothetical Protein ◽  
Abiotic Surfaces ◽  
Insertional Inactivation ◽  
Tooth Surfaces ◽  
Virulence Properties

ABSTRACT Streptococcus mutans has been strongly implicated as the principal etiological agent in dental caries. One of the important virulence properties of these organisms is their ability to form biofilms known as dental plaque on tooth surfaces. Since the roles of sucrose and glucosyltransferases in S. mutans biofilm formation have been well documented, we focused our attention on sucrose-independent factors. We have initially identified several mutants that appear to be defective in biofilm formation on abiotic surfaces by an insertional inactivation mutagenesis strategy applied to S. mutans. A total of 27 biofilm-defective mutants were isolated and analyzed in this study. From these mutants, three genes were identified. One of the mutants was defective in the Bacillus subtilis lytR homologue. Another of the biofilm-defective mutants isolated was a yulF homologue, which encodes a hypothetical protein of B. subtilis whose function in biofilm formation is unknown. The vast majority of the mutants were defective in the comB gene required for competence. We therefore have constructed and examined comACDE null mutants. These mutants were also found to be attenuated in biofilm formation. Biofilm formation by several other regulatory gene mutants were also characterized using an in vitro biofilm-forming assay. These results suggest that competence genes as well as the sgp and dgk genes may play important roles in S. mutans biofilm formation.

scholarly journals Trk2 Potassium Transport System in Streptococcus mutans and Its Role in Potassium Homeostasis, Biofilm Formation, and Stress Tolerance

2016 ◽  
Vol 198 (7) ◽  
pp. 1087-1100 ◽  
Author(s):  
Gursonika Binepal ◽  
Kamal Gill ◽  
Paula Crowley ◽  
Martha Cordova ◽  
L. Jeannine Brady ◽  
...  
Keyword(s):  
Stress Tolerance ◽  
Streptococcus Mutans ◽  
Transport System ◽  
Biofilm Formation ◽  
Cellular Response ◽  
Pathogenic Bacteria ◽  
Transport Systems ◽  
Content Type ◽  
Growth And Survival ◽  
Dental Biofilm

ABSTRACTPotassium (K+) is the most abundant cation in the fluids of dental biofilm. The biochemical and biophysical functions of K+and a variety of K+transport systems have been studied for most pathogenic bacteria but not for oral pathogens. In this study, we establish the modes of K+acquisition inStreptococcus mutansand the importance of K+homeostasis for its virulence attributes. TheS. mutansgenome harbors four putative K+transport systems that included two Trk-like transporters (designated Trk1 and Trk2), one glutamate/K+cotransporter (GlnQHMP), and a channel-like K+transport system (Kch). Mutants lacking Trk2 had significantly impaired growth, acidogenicity, aciduricity, and biofilm formation. [K+] less than 5 mM eliminated biofilm formation inS. mutans. The functionality of the Trk2 system was confirmed by complementing anEscherichia coliTK2420 mutant strain, which resulted in significant K+accumulation, improved growth, and survival under stress. Taken together, these results suggest that Trk2 is the main facet of the K+-dependent cellular response ofS. mutansto environment stresses.IMPORTANCEBiofilm formation and stress tolerance are important virulence properties of caries-causingStreptococcus mutans. To limit these properties of this bacterium, it is imperative to understand its survival mechanisms. Potassium is the most abundant cation in dental plaque, the natural environment ofS. mutans. K+is known to function in stress tolerance, and bacteria have specialized mechanisms for its uptake. However, there are no reports to identify or characterize specific K+transporters inS. mutans. We identified the most important system for K+homeostasis and its role in the biofilm formation, stress tolerance, and growth. We also show the requirement of environmental K+for the activity of biofilm-forming enzymes, which explains why such high levels of K+would favor biofilm formation.

scholarly journals A Novel Gene Involved in the Survival of Streptococcus mutans under Stress Conditions

2013 ◽  
Vol 80 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Dan Li ◽  
Yukie Shibata ◽  
Toru Takeshita ◽  
Yoshihisa Yamashita
Keyword(s):  
Streptococcus Mutans ◽  
Streptococcus Pyogenes ◽  
Biofilm Formation ◽  
Acid Tolerance ◽  
Stress Conditions ◽  
Insertion Mutagenesis ◽  
Trna Modification ◽  
Content Type ◽  
Virulence Proteins ◽  
Random Insertion

ABSTRACTAStreptococcus mutansmutant defective in aciduricity was constructed by random-insertion mutagenesis. Sequence analysis of the mutant revealed a mutation ingidA, which is known to be involved in tRNA modification inStreptococcus pyogenes. Complementation ofgidAbyS. pyogenesgidArecovered the acid tolerance ofS. mutans. Although thegidA-inactivatedS. pyogenesmutant exhibited significantly reduced expression of multiple extracellular virulence proteins, theS. mutansmutant did not. On the other hand, thegidAmutant ofS. mutansshowed reduced ability to withstand exposure to other stress conditions (high osmotic pressure, high temperature, and bacitracin stress) besides an acidic environment. In addition, loss of GidA decreased the capacity for glucose-dependent biofilm formation by over 50%. This study revealed thatgidAplays critical roles in the survival ofS. mutansunder stress conditions, including lower pH.

scholarly journals Effect of a Berry Polyphenolic Fraction on Biofilm Formation, Adherence Properties and Gene Expression of Streptococcus mutans and Its Biocompatibility with Oral Epithelial Cells

Antibiotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 46
Author(s):  
Mariem Souissi ◽  
Amel Ben Lagha ◽  
Kamel Chaieb ◽  
Daniel Grenier
Keyword(s):  
Epithelial Cells ◽  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Cell Model ◽  
Pcr Analysis ◽  
Adhesion Properties ◽  
Oral Epithelial Cells ◽  
Polymerase Chain ◽  
Oral Epithelial ◽  
Wild Blueberry

The ability of Streptococcus mutans to adhere to oral surfaces and form biofilm is a key step in the tooth decay process. The aim of this study was to investigate a berry (wild blueberry, cranberry, and strawberry) polyphenolic fraction, commercialized as Orophenol®, for its antibacterial, anti-biofilm, and anti-adhesion properties on S. mutans. Moreover, the biocompatibility of the fraction with human oral epithelial cells was assessed. Phenolic acids, flavonoids (flavonols, anthocyanins, flavan-3-ols), and procyanidins made up 10.71%, 19.76%, and 5.29% of the berry polyphenolic fraction, respectively, as determined by chromatography and mass spectrometry. The berry polyphenolic preparation dose-dependently inhibited S. mutans biofilm formation while not reducing bacterial growth. At concentrations ranging from 250 to 1000 µg/mL, the fraction inhibited the adhesion of S. mutans to both saliva-coated hydroxyapatite and saliva-coated nickel–chrome alloy. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed that incubating S. mutans with the berry polyphenolic fraction was associated with a reduced expression of luxS gene, which regulates quorum sensing in S. mutans. The berry fraction did not show any significant cytotoxicity in an oral epithelial cell model. In conclusion, Orophenol®, which is a mixture of polyphenols from wild blueberry, cranberry and strawberry, possesses interesting anti-caries properties while being compatible with oral epithelial cells.

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