The vicK gene of Streptococcus mutans mediates its cariogenicity via exopolysaccharides metabolism

AbstractStreptococcus mutans (S. mutans) is generally regarded as a major contributor to dental caries because of its ability to synthesize extracellular polysaccharides (EPS) that aid in the formation of plaque biofilm. The VicRKX system of S. mutans plays an important role in biofilm formation. The aim of this study was to investigate the effects of vicK gene on specific characteristics of EPS in S. mutans biofilm. We constructed single-species biofilms formed by different mutants of vicK gene. Production and distribution of EPS were detected through atomic force microscopy, scanning electron microscopy and confocal laser scanning microscopy. Microcosmic structures of EPS were analyzed by gel permeation chromatography and gas chromatography-mass spectrometry. Cariogenicity of the vicK mutant was assessed in a specific pathogen-free rat model. Transcriptional levels of cariogenicity-associated genes were confirmed by quantitative real-time polymerase chain reaction. The results showed that deletion of vicK gene suppressed biofilm formation as well as EPS production, and EPS were synthesized mostly around the cells. Molecular weight and monosaccharide components underwent evident alterations. Biofilms formed in vivo were sparse and contributed a decreased degree of caries. Moreover, expressional levels of genes related to EPS synthesis were down-regulated, except for gtfB. Our report demonstrates that vicK gene enhances biofilm formation and subsequent caries development. And this may due to its regulations on EPS metabolism, like synthesis or microcosmic features of EPS. This study suggests that vicK gene and EPS can be considered as promising targets to modulate dental caries.

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Comparison of Cariogenic Characteristics between Fluoride-sensitive and Fluoride-resistant Streptococcus mutans

THE JOURNAL OF THE KOREAN ACADEMY OF PEDTATRIC DENTISTRY ◽

10.5933/jkapd.2020.47.4.397 ◽

2020 ◽

Vol 47 (4) ◽

pp. 397-405

Author(s):

Seung-Hwan Ong ◽

Jongsoo Kim ◽

Dong-Heon Baek ◽

Seunghoon Yoo

Keyword(s):

Streptococcus Mutans ◽

Biofilm Formation ◽

Laser Scanning ◽

Single Species ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Rt Pcr ◽

Oral Biofilm ◽

Low Levels ◽

Number Of Bacteria

The aim of this study is to compare cariogenic characteristics of fluoride-sensitive Streptococcus mutans [fluoride-sensitive (FS) S. mutans ] and fluoride-resistant Streptococcus mutans [fluoride-resistant (FR) S. mutans] in the presence of sucrose, and to evaluate its effect on cariogenic biofilm formation. S. mutans ATCC 25175 was continuously cultured in trypticase soy broth (TSB) containing NaF (70 ppm) for 40 days to generate FR S. mutans . FS and FR S. mutans were inoculated in TSB with or without 2% sucrose, and optical density and pH were measured every hour. An oral biofilm was formed using saliva bacteria and analyzed through confocal laser scanning microscopy and CFU count. Finally, the expression of glucosyltransferases genes of both S. mutans was investigated through RT-PCR. FR S. mutans exhibited slower growth and lower acidogenicity in the presence of sucrose compared to FS S. mutans . Both cariogenic and single species biofilm formation was lower in the presence of FR S. mutans , along with reduced number of bacteria. FR S. mutans showed significantly low levels of gtfB, gtfC, and gtfD expression compared to FS S. mutans . On the basis of results, FR S. mutans may be less virulent in the induction of dental caries.

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The Interaction of N-Acetylcysteine and Serum Transferrin Promotes Bacterial Biofilm Formation

Cellular Physiology and Biochemistry ◽

10.1159/000487566 ◽

2018 ◽

Vol 45 (4) ◽

pp. 1399-1409 ◽

Cited By ~ 7

Author(s):

Supeng Yin ◽

Bei Jiang ◽

Guangtao Huang ◽

Yulong Zhang ◽

Bo You ◽

...

Keyword(s):

Human Serum ◽

Biofilm Formation ◽

Laser Scanning ◽

Serum Proteins ◽

Venous Catheter ◽

Bacterial Biofilm ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Bacterial Strains

Background/Aims: N-acetylcysteine (NAC) is a novel and promising agent with activity against bacterial biofilms. Human serum also inhibits biofilm formation by some bacteria. We tested whether the combination of NAC and human serum offers greater anti-biofilm activity than either agent alone. Methods: Microtiter plate assays and confocal laser scanning microscopy were used to evaluate bacterial biofilm formation in the presence of NAC and human serum. qPCR was used to examine expression of selected biofilm-associated genes. Extracellular matrix (ECM) was observed by transmission electron microscopy. The antioxidants GSH or ascorbic acid were used to replace NAC, and human transferrin, lactoferrin, or bovine serum albumin were used to replace serum proteins in biofilm formation assays. A rat central venous catheter model was developed to evaluate the effect of NAC on biofilm formation in vivo. Results: NAC and serum together increased biofilm formation by seven different bacterial strains. In Staphylococcus aureus, expression of genes for some global regulators and for genes in the ica-dependent pathway increased markedly. In Pseudomonas aeruginosa, transcription of las, the PQS quorum sensing (QS) systems, and the two-component system GacS/GacA increased significantly. ECM production by S. aureus and P. aeruginosa was also enhanced. The potentiation of biofilm formation is due mainly to interaction between NAC and transferrin. Intravenous administration of NAC increased colonization by S. aureus and P. aeruginosa on implanted catheters. Conclusions: NAC used intravenously or in the presence of blood increases bacterial biofilm formation rather than inhibits it.

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Effects of cigarette smoking on the growth of Streptococcus mutans biofilms: an in vitro study

10.21203/rs.3.rs-221658/v1 ◽

2021 ◽

Author(s):

Ye Han

Keyword(s):

Treatment Group ◽

Cigarette Smoking ◽

Streptococcus Mutans ◽

Laser Scanning ◽

Water Soluble ◽

Laser Scanning Microscopy ◽

Extracellular Polysaccharides ◽

Confocal Laser ◽

Control Group

Abstract This study aimed to investigate the differences in growth and virulence (EPSs and acidogenicity) of Streptococcus mutans biofilms (S. mutans) according to the different times of cigarette smoking (CS) treatment. S. mutans biofilms (74-hour-old) were formed on saliva-coated hydroxyapatite disks. The biofilms were treated with CS at different times per day (one time, three times, and six times/day). The control group did not receive CS treatment. Acidogenicity, dry weight, colony-forming units, water-soluble/insoluble extracellular polysaccharides, and intracellular polysaccharides were analyzed and confocal laser scanning microscopy images were obtained of the 74-h-old biofilms. The 74-h-old biofilms on sHA discs in the 6 times/day CS treatment group showed the lowest biofilm accumulation and extracellular polysaccharide amount compared with the control group and other CS treatment groups. In the CLSM study, the biofilms in the six times/day CS treatment group also showed the lowest bacterial count (live and dead cells) and EPS biovolume. CS has an obvious inhibition on the growth of S. mutans biofilms, the degree of inhibition is proportional to the number of CS treatments.

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Assessment of Genes Associated with Streptococcus mutans Biofilm Morphology

Applied and Environmental Microbiology ◽

10.1128/aem.00614-06 ◽

2006 ◽

Vol 72 (9) ◽

pp. 6277-6287 ◽

Cited By ~ 34

Author(s):

Mizuho Motegi ◽

Yuzo Takagi ◽

Hideo Yonezawa ◽

Nobuhiro Hanada ◽

Jun Terajima ◽

...

Keyword(s):

Streptococcus Mutans ◽

Biofilm Formation ◽

Laser Scanning ◽

Protein Gene ◽

Laser Scanning Microscopy ◽

Live Cells ◽

Confocal Laser ◽

Morphological Development ◽

Phosphotransferase System ◽

Whole Saliva

ABSTRACT Streptococcus mutans, the major pathogen responsible for dental caries in humans, is a biofilm-forming bacterium. In the present study, 17 different pulsed-field gel electrophoresis patterns of genomic DNA were identified in S. mutans organisms isolated clinically from whole saliva. The S. mutans isolates showed different abilities to form biofilms on polystyrene surfaces in semidefined minimal medium cultures. Following cultivation in a flow cell system in tryptic soy broth with 0.25% sucrose and staining using a BacLight LIVE/DEAD system, two strains, designated FSC-3 and FSC-4, showed the greatest and least, respectively, levels of biofilm formation when examined with confocal laser scanning microscopy. Further, image analyses of spatial distribution and architecture were performed to quantify the merged green (live cells) and red (dead cells) light. The light intensity of the FSC-3 biofilm was greater than that of the FSC-4 biofilm in the bottom area but not in the top area. S. mutans whole-genome array results showed that approximately 3.8% of the genes were differentially expressed in the two strains, of which approximately 2.2%, including bacitracin transport ATP-binding protein gene glrA and a BLpL-like putative immunity protein gene, were activated in FSC-3. In addition, about 1.6% of the genes, including those associated with phosphotransferase system genes, were repressed. Analyses of the glrA-deficient strains and reverse transcription-PCR confirmed the role of the gene in biofilm formation. Differential assessment of biofilm-associated genes in clinical strains may provide useful information for understanding the morphological development of streptococcal biofilm, as well as for colonization of S. mutans.

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Role of the luxS Gene in Initial Biofilm Formation by Streptococcus mutans

Journal of Molecular Microbiology and Biotechnology ◽

10.1159/000371816 ◽

2015 ◽

Vol 25 (1) ◽

pp. 60-68 ◽

Cited By ~ 24

Author(s):

Zhiyan He ◽

Jingping Liang ◽

Zisheng Tang ◽

Rui Ma ◽

Huasong Peng ◽

...

Keyword(s):

Streptococcus Mutans ◽

Mutant Strain ◽

Biofilm Formation ◽

Type Strain ◽

Laser Scanning ◽

Wild Type Strain ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Wild Type ◽

Initial Biofilm

Quorum sensing (QS) is a process by which bacteria communicate with each other by secreting chemical signals called autoinducers (AIs). Among Gram-negative and Gram-positive bacteria, AI-2 synthesized by the LuxS enzyme is widespread. The aim of this study was to evaluate the effect of QS luxS gene on initial biofilm formation by Streptococcus mutans. The bacterial cell surface properties, including cell hydrophobicity (bacterial adherence to hydrocarbons) and aggregation, which are important for initial adherence during biofilm development, were investigated. The biofilm adhesion assay was evaluated by the MTT method. The structures of the 5-hour biofilms were observed by using confocal laser scanning microscopy, and QS-related gene expressions were investigated by real-time PCR. The luxS mutant strain exhibited higher biofilm adherence and aggregation, but lower hydrophobicity than the wild-type strain. The confocal laser scanning microscopy images revealed that the wild-type strain tended to form smaller aggregates with uniform distribution, whereas the luxS mutant strain aggregated into distinct clusters easily discernible in the generated biofilm. Most of the genes examined were downregulated in the biofilms formed by the luxS mutant strain, except the gtfB gene. QS luxS gene can affect the initial biofilm formation by S. mutans.

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Exopolysaccharide Carbohydrate Structure and Biofilm Formation by Rhizobium leguminosarum bv. trifolii Strains Inhabiting Nodules of Trifoliumrepens Growing on an Old Zn–Pb–Cd-Polluted Waste Heap Area

International Journal of Molecular Sciences ◽

10.3390/ijms22062808 ◽

2021 ◽

Vol 22 (6) ◽

pp. 2808

Author(s):

Ewa Oleńska ◽

Wanda Małek ◽

Urszula Kotowska ◽

Jerzy Wydrych ◽

Weronika Polińska ◽

...

Keyword(s):

Trifolium Repens ◽

Biofilm Formation ◽

Laser Scanning ◽

Rhizobium Leguminosarum ◽

Reference Site ◽

Laser Scanning Microscopy ◽

Gas Chromatography Mass Spectrometry ◽

Metal Exposure ◽

Confocal Laser ◽

Lead And Cadmium

Heavy metals polluting the 100-year-old waste heap in Bolesław (Poland) are acting as a natural selection factor and may contribute to adaptations of organisms living in this area, including Trifolium repens and its root nodule microsymbionts—rhizobia. Exopolysaccharides (EPS), exuded extracellularly and associated with bacterial cell walls, possess variable structures depending on environmental conditions; they can bind metals and are involved in biofilm formation. In order to examine the effects of long-term exposure to metal pollution on EPS structure and biofilm formation of rhizobia, Rhizobium leguminosarum bv. trifolii strains originating from the waste heap area and a non-polluted reference site were investigated for the characteristics of the sugar fraction of their EPS using gas chromatography mass-spectrometry and also for biofilm formation and structural characteristics using confocal laser scanning microscopy under control conditions as well as when exposed to toxic concentrations of zinc, lead, and cadmium. Significant differences in EPS structure, biofilm thickness, and ratio of living/dead bacteria in the biofilm were found between strains originating from the waste heap and from the reference site, both without exposure to metals and under metal exposure. Received results indicate that studied rhizobia can be assumed as potentially useful in remediation processes.

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Nicotine Enhances Interspecies Relationship betweenStreptococcus mutansandCandida albicans

BioMed Research International ◽

10.1155/2017/7953920 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9 ◽

Cited By ~ 5

Author(s):

Shiyu Liu ◽

Wei Qiu ◽

Keke Zhang ◽

Xuedong Zhou ◽

Biao Ren ◽

...

Keyword(s):

Biofilm Formation ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Extracellular Polysaccharides ◽

Confocal Laser ◽

Fungal Cell ◽

Biofilm Model ◽

Structure Synthesis ◽

Biofilm Structure ◽

Synergistic Relationship

Streptococcus mutansandCandida albicansare common microorganisms in the human oral cavity. The synergistic relationship between these two species has been deeply explored in many studies. In the present study, the effect of alkaloid nicotine on the interspecies betweenS. mutansandC. albicansis explored. We developed a dual-species biofilm model and studied biofilm biomass, biofilm structure, synthesis of extracellular polysaccharides (EPS), and expression of glucosyltransferases (Gtfs). Biofilm formation and bacterial and fungal cell numbers in dual-species biofilms increased in the presence of nicotine. MoreC. albicanscells were present in the dual-species biofilms in the nicotine-treated groups as determined by scanning electron microscopy. The synthesis of EPS was increased by 1 mg/ml of nicotine as detected by confocal laser scanning microscopy. The result of qRT-PCR showedgtfsexpression was upregulated when 1 mg/ml of nicotine was used. We speculate that nicotine promoted the growth ofS. mutans, and moreS. mutanscells attracted moreC. albicanscells due to the interaction between two species. SinceS. mutansandC. albicansare putative pathogens for dental caries, the enhancement of the synergistic relationship by nicotine may contribute to caries development in smokers.

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Influence of BrpA on Critical Virulence Attributes of Streptococcus mutans

Journal of Bacteriology ◽

10.1128/jb.188.8.2983-2992.2006 ◽

2006 ◽

Vol 188 (8) ◽

pp. 2983-2992 ◽

Cited By ~ 74

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.

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R-Thanatin Inhibits Growth and Biofilm Formation of Methicillin-Resistant Staphylococcus epidermidisIn VivoandIn Vitro

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00504-13 ◽

2013 ◽

Vol 57 (10) ◽

pp. 5045-5052 ◽

Cited By ~ 13

Author(s):

Zheng Hou ◽

Fei Da ◽

Baohui Liu ◽

Xiaoyan Xue ◽

Xiuli Xu ◽

...

Keyword(s):

Biofilm Formation ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Drug Candidate ◽

Coagulase Negative Staphylococci ◽

Methicillin Resistant ◽

Content Type

ABSTRACTStaphylococcus epidermidisis one of the most frequent causes of device-associated infections, because it is known to cause biofilms that grow on catheters or other surgical implants. The persistent increasing resistance ofS. epidermidisand other coagulase-negative staphylococci (CoNS) has driven the need for newer antibacterial agents with innovative therapeutic strategies. Thanatin is reported to display potent antibiotic activities, especially against extended-spectrum-beta-lactamase-producingEscherichia coli. The present study aimed to investigate whether a shorter derivative peptide (R-thanatin) could be used as a novel antibacterial agent. We found that R-thanatin was highly potentin vitroagainst coagulase-negative staphylococci, such asS. epidermidis,S. haemolyticus, andS. hominis, and inhibited biofilm formation at subinhibitory concentrations. Properties of little toxicity to human red blood cells (hRBCs) and human umbilical vein endothelial cells, a low incidence of resistance, and relatively high stability in plasma were confirmed. Excellentin vivoprotective effects were also observed using a methicillin-resistantS. epidermidis(MRSE)-induced urinary tract infection rat model. Electron microscopy and confocal laser-scanning microscopy analyses suggested that R-thanatin disturbed cell division of MRSE severely, which might be the reason for inhibition of MRSE growth. These findings indicate that R-thanatin is active against the growth and biofilm formation of MRSEin vitroandin vivo. R-thanatin might be considered as a specific drug candidate for treating CoNS infections.

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Effect of LongZhang Gargle on Dual-Species Biofilm of Candida albicans and Streptococcus mutans

BioMed Research International ◽

10.1155/2021/6654793 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Jinglei Gong ◽

Die Hu ◽

Jinzhi He ◽

Ling Zou ◽

Zhu Chen ◽

...

Keyword(s):

Candida Albicans ◽

Streptococcus Mutans ◽

Hot Spot ◽

Fungal Spores ◽

Cell Activity ◽

Single Species ◽

Laser Scanning Microscopy ◽

Oral Disease ◽

Extracellular Polysaccharides ◽

Confocal Laser

Bioactive natural products have become a hot spot for oral disease treatments. At the present study, LongZhang Gargle was investigated for its effects on single-species biofilms of Candida albicans and dual-species biofilms of Candida albicans and Streptococcus mutans. Two different models of single and dual-species biofilms were grown in YNBB medium under appropriate conditions. Biofilm biomass, biofilm architecture, and cell activity in biofilms were assessed using Crystal Violet Staining, MTT, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Significant reductions of biofilm biomass and fungus activity were obtained when treated with LongZhang Gargle at 2% ( P < 0.05 ), 4% ( P < 0.05 ), and 8% ( P < 0.05 ) in single-species biofilms of C. albicans, and at 4% ( P < 0.05 ) and 8% ( P < 0.05 ) in double-species biofilms. Suppression of density, thickness, and the proportion of hyphae and fungal spores were obtained under SEM and CLSM. In conclusion, LongZhang Gargle affects single and dual-species biofilms by inhibiting biofilm biomass, cell activity, and formation of hyphae, but it does not affect the production of Extracellular polysaccharides (EPS). We speculate that LongZhang Gargle would be a promising natural drug, which can be used in treatment against C. albicans and S. mutans in oral diseases.

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