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Microbiology Spectrum Jan 2019As a major etiological agent of human dental caries, resides primarily in biofilms that form on the tooth surfaces, also known as dental plaque. In addition to caries,...
As a major etiological agent of human dental caries, resides primarily in biofilms that form on the tooth surfaces, also known as dental plaque. In addition to caries, is responsible for cases of infective endocarditis with a subset of strains being indirectly implicated with the onset of additional extraoral pathologies. During the past 4 decades, functional studies of have focused on understanding the molecular mechanisms the organism employs to form robust biofilms on tooth surfaces, to rapidly metabolize a wide variety of carbohydrates obtained from the host diet, and to survive numerous (and frequent) environmental challenges encountered in oral biofilms. In these areas of research, has served as a model organism for ground-breaking new discoveries that have, at times, challenged long-standing dogmas based on bacterial paradigms such as and . In addition to sections dedicated to carbohydrate metabolism, biofilm formation, and stress responses, this article discusses newer developments in biology research, namely, how interspecies and cross-kingdom interactions dictate the development and pathogenic potential of oral biofilms and how next-generation sequencing technologies have led to a much better understanding of the physiology and diversity of as a species.
Topics: Biofilms; Carbohydrate Metabolism; Dental Caries; Dental Plaque; Humans; Signal Transduction; Streptococcus mutans
PubMed: 30657107
DOI: 10.1128/microbiolspec.GPP3-0051-2018 -
European Journal of Clinical... Apr 2014In some diseases, a very important role is played by the ability of bacteria to form multi-dimensional complex structure known as biofilm. The most common disease of the... (Review)
Review
In some diseases, a very important role is played by the ability of bacteria to form multi-dimensional complex structure known as biofilm. The most common disease of the oral cavity, known as dental caries, is a top leader. Streptococcus mutans, one of the many etiological factors of dental caries, is a microorganism which is able to acquire new properties allowing for the expression of pathogenicity determinants determining its virulence in specific environmental conditions. Through the mechanism of adhesion to a solid surface, S. mutans is capable of colonizing the oral cavity and also of forming bacterial biofilm. Additional properties enabling S. mutans to colonize the oral cavity include the ability to survive in an acidic environment and specific interaction with other microorganisms colonizing this ecosystem. This review is an attempt to establish which characteristics associated with biofilm formation--virulence determinants of S. mutans--are responsible for the development of dental caries. In order to extend the knowledge of the nature of Streptococcus infections, an attempt to face the following problems will be made: Biofilm formation as a complex process of protein-bacterium interaction. To what extent do microorganisms of the cariogenic flora exemplified by S. mutans differ in virulence determinants "expression" from microorganisms of physiological flora? How does the environment of the oral cavity and its microorganisms affect the biofilm formation of dominant species? How do selected inhibitors affect the biofilm formation of cariogenic microorganisms?
Topics: Biofilms; Dental Caries; Humans; Streptococcus mutans; Tooth; Virulence
PubMed: 24154653
DOI: 10.1007/s10096-013-1993-7 -
PLoS Pathogens Dec 2021Lysine acetylation is a frequently occurring post-translational modification (PTM), emerging as an important metabolic regulatory mechanism in prokaryotes. This process...
Lysine acetylation is a frequently occurring post-translational modification (PTM), emerging as an important metabolic regulatory mechanism in prokaryotes. This process is achieved enzymatically by the protein acetyltransferase (KAT) to specifically transfer the acetyl group, or non-enzymatically by direct intermediates (acetyl phosphate or acetyl-CoA). Although lysine acetylation modification of glucosyltransferases (Gtfs), the important virulence factor in Streptococcus mutans, was reported in our previous study, the KAT has not been identified. Here, we believe that the KAT ActG can acetylate Gtfs in the enzymatic mechanism. By overexpressing 15 KATs in S. mutans, the synthesized water-insoluble extracellular polysaccharides (EPS) and biofilm biomass were measured, and KAT (actG) was identified. The in-frame deletion mutant of actG was constructed to validate the function of actG. The results showed that actG could negatively regulate the water-insoluble EPS synthesis and biofilm formation. We used mass spectrometry (MS) to identify GtfB and GtfC as the possible substrates of ActG. This was also demonstrated by in vitro acetylation assays, indicating that ActG could increase the acetylation levels of GtfB and GtfC enzymatically and decrease their activities. We further found that the expression level of actG in part explained the virulence differences in clinically isolated strains. Moreover, overexpression of actG in S. mutans attenuated its cariogenicity in the rat caries model. Taken together, our study demonstrated that the KAT ActG could induce the acetylation of GtfB and GtfC enzymatically in S. mutans, providing insights into the function of lysine acetylation in bacterial virulence and pathogenicity.
Topics: Acetylation; Acetyltransferases; Animals; Biofilms; Female; Glucosyltransferases; Lysine; Rats; Rats, Sprague-Dawley; Streptococcus mutans; Virulence
PubMed: 34860858
DOI: 10.1371/journal.ppat.1010134 -
Microbiology (Reading, England) Mar 2013Despite the enormous contributions of the bacterial paradigms Escherichia coli and Bacillus subtilis to basic and applied research, it is well known that no single... (Review)
Review
Despite the enormous contributions of the bacterial paradigms Escherichia coli and Bacillus subtilis to basic and applied research, it is well known that no single organism can be a perfect representative of all other species. However, given that some bacteria are difficult, or virtually impossible, to cultivate in the laboratory, that some are recalcitrant to genetic and molecular manipulation, and that others can be extremely dangerous to manipulate, the use of model organisms will continue to play an important role in the development of basic research. In particular, model organisms are very useful for providing a better understanding of the biology of closely related species. Here, we discuss how the lifestyle, the availability of suitable in vitro and in vivo systems, and a thorough understanding of the genetics, biochemistry and physiology of the dental pathogen Streptococcus mutans have greatly advanced our understanding of important areas in the field of bacteriology such as interspecies biofilms, competence development and stress responses. In this article, we provide an argument that places S. mutans, an organism that evolved in close association with the human host, as a novel Gram-positive model organism.
Topics: Biofilms; DNA Transformation Competence; Humans; Streptococcus mutans; Stress, Physiological
PubMed: 23393147
DOI: 10.1099/mic.0.066134-0 -
Molecules (Basel, Switzerland) Aug 2020bacterium is implicated in the pathogenesis of dental caries due to the production of biofilm and organic acids from dietary sucrose. Despite the availability of...
bacterium is implicated in the pathogenesis of dental caries due to the production of biofilm and organic acids from dietary sucrose. Despite the availability of various means of prophylaxis, caries still has a high worldwide prevalence. Therefore, it is important to find new pharmaceuticals to inhibit biofilm formation and acidogenicity. The aim of the current study was to evaluate the activity of lauryl gallate (dodecyl gallate) against acidogenicity, the expression of biofilm-associated genes, and biofilm development on solid surfaces (polystyrene, glass). The biofilm quantities produced by bacteria were assessed using colorimetric and optical profilometry techniques. Acidogenicity was evaluated by measuring the pH of the biofilm growth medium with microelectrode. Assessment of the expression of gene coding for glucan-binding protein B (), glucosyltranferases B, -C, -D (), and the F-ATPase β subunit of F protein () was carried out using a quantitative reverse transcription-polymerase chain reaction (RT-qPCR). The results demonstrate the capacity of lauryl gallate to significantly inhibit acidogenicity and biofilm development on solid surfaces, in a dose-dependent manner, compared to untreated bacteria ( < 0.05). The highest activity of lauryl gallate occurred at a concentration of 98.98 µM, at which it suppressed biofilm formation by 100% and lowered pH levels by 98%. The effect of lauryl gallate treatment on gene expression changes, as demonstrated by our RT-qPCR data, was limited to the gene only, was a significant (48%) decrease in gene expression, obtained for the biofilm-producing bacteria, while a 300% increase in fold change for the same gene occurred in the planktonic cells. It is important to note that in previous studies we showed a broader effect of related derivatives. However, a similar magnitude of difference in effects between biofilm and planktonic cells for the gene was obtained after treatment with octyl gallate and reverse magnitude for the same gene after treatment with ethyl gallate. Therefore, to ascertain the possible direct or indirect effects of lauryl gallate, as well as octyl gallate and ethyl gallate, more research is needed to examine the effects on the amount of enzymes and on the enzymatic activity of the products of the affected genes that are involved in the production and maintenance of biofilm by
Topics: Biofilms; Gallic Acid; Gene Expression Regulation, Bacterial; Glass; Hydrogen-Ion Concentration; Polystyrenes; Streptococcus mutans
PubMed: 32823528
DOI: 10.3390/molecules25163685 -
Journal of Bacteriology Jan 2019Proper envelope biogenesis of , a biofilm-forming and dental caries-causing oral pathogen, requires two paralogs ( and ) of the universally conserved YidC/Oxa1/Alb3...
Proper envelope biogenesis of , a biofilm-forming and dental caries-causing oral pathogen, requires two paralogs ( and ) of the universally conserved YidC/Oxa1/Alb3 family of membrane integral chaperones and insertases. The deletion of either paralog attenuates virulence , but the mechanisms of disruption remain unclear. Here, we determined whether the deletion of affects cell surface properties, extracellular glucan production, and/or the structural organization of the exopolysaccharide (EPS) matrix and biophysical properties of biofilm. Compared to the wild type, the Δ2 mutant lacked staining with fluorescent vancomycin at the division septum, while the Δ mutant resembled the wild type. Additionally, the deletion of either or resulted in less insoluble glucan synthesis but produced more soluble glucans, especially at early and mid-exponential-growth phases. Alteration of glucan synthesis by both mutants yielded biofilms with less dry weight and insoluble EPS. In particular, the deletion of resulted in a significant reduction in biofilm biomass and pronounced defects in the spatial organization of the EPS matrix, thus modifying the three-dimensional (3D) biofilm architecture. The defective biofilm harbored smaller bacterial clusters with high cell density and less surrounding EPS than those of the wild type, which was stiffer in compression yet more susceptible to removal by shear. Together, our results indicate that the elimination of either paralog results in changes to the cell envelope and glucan production that ultimately disrupts biofilm development and EPS matrix structure/composition, thereby altering the physical properties of the biofilms and facilitating their removal. YidC proteins, therefore, represent potential therapeutic targets for cariogenic biofilm control. YidC proteins are membrane-localized chaperone insertases that are universally conserved in all bacteria and are traditionally studied in the context of membrane protein insertion and assembly. Both YidC paralogs of the cariogenic pathogen are required for proper envelope biogenesis and full virulence, indicating that these proteins may also contribute to optimal biofilm formation in streptococci. Here, we show that the deletion of either results in changes to the structure and physical properties of the EPS matrix produced by , ultimately impairing optimal biofilm development, diminishing its mechanical stability, and facilitating its removal. Importantly, the universal conservation of bacterial orthologs, combined with our findings, provide a rationale for YidC as a possible drug target for antibiofilm therapies.
Topics: Bacterial Proteins; Biofilms; Biophysical Phenomena; Cell Wall; Extracellular Polymeric Substance Matrix; Gene Deletion; Glucans; Streptococcus mutans
PubMed: 30322852
DOI: 10.1128/JB.00396-18 -
Microbial Genomics Feb 2017The Cid/Lrg system is central to the physiology of this cariogenic organism, affecting oxidative stress resistance, biofilm formation and competence. Previous...
The Cid/Lrg system is central to the physiology of this cariogenic organism, affecting oxidative stress resistance, biofilm formation and competence. Previous transcriptome analyses of (responsible for the regulation of expression) and mutants have revealed pleiotropic effects on carbohydrate metabolism and stress resistance genes. In this study, it was found that an mutant, previously shown to have diminished aerobic and oxidative stress growth, was also much more growth impaired in the presence of heat and vancomycin stresses, relative to wild-type, and mutants. To obtain a more holistic picture of LrgAB and its involvement in stress resistance, RNA sequencing and bioinformatics analyses were used to assess the transcriptional response of wild-type and isogenic mutants under anaerobic (control) and stress-inducing culture conditions (aerobic, heat and vancomycin). Hierarchical clustering and principal components analyses of all differentially expressed genes revealed that the most distinct gene expression profiles between UA159 and mutant occurred during aerobic and high-temperature growth. Similar to previous studies of a mutant, stress transcriptomes were characterized by a variety of gene expression changes related to genomic islands, CRISPR-C as systems, ABC transporters, competence, bacteriocins, glucosyltransferases, protein translation, tricarboxylic acid cycle, carbohydrate metabolism/storage and transport. Notably, expression of was upregulated in the wild-type strain under all three stress conditions. Collectively, these results demonstrate that mutation of alters the transcriptional response to stress, and further support the idea that the Cid/Lrg system acts to promote cell homeostasis in the face of environmental stress.
Topics: Bacterial Proteins; Drug Resistance, Microbial; Gene Expression Regulation, Bacterial; Heat-Shock Response; Humans; Membrane Proteins; Oxidative Stress; Streptococcus mutans; Stress, Physiological; Transcriptome; Up-Regulation; Vancomycin
PubMed: 28348880
DOI: 10.1099/mgen.0.000104 -
Scientific Reports Jun 2021Streptococcus mutans produces bacteriocins that show antibacterial activity against several bacteria. However, comprehensive analysis of these bacteriocins has not been...
Streptococcus mutans produces bacteriocins that show antibacterial activity against several bacteria. However, comprehensive analysis of these bacteriocins has not been well done. In this study, we isolated 125 S. mutans strains from volunteers and determined their whole genome sequence. Based on the genome analysis, the distribution of each bacteriocin gene (mutacins I-IV, K8 and Smb) was investigated. We found 17, 5, and 2 strains showing 100% matches with mutacin I, mutacin II and mutacin III, respectively. Five mutacin III-positive strains had 2 mismatches compared to mature mutacin III. In 67 mutacin IV-positive strains, 38 strains showed 100% match with mutacin IV, while 29 strains showed some variations. In 23 mutacin K8- and 32 mutacin Smb-positive strains, all except one mutacin K8-positive strain showed 100% match with the mature peptides. Among 125 strains, 84 (65.1%), 26 (20.2%), and 5 (3.9%) strains were positive for one, two and three bacteriocin genes, respectively. Then, the antibacterial activity against oral streptococci and other oral bacterial species was investigated by using bacteriocin gene single-positive strains. Each bacteriocin gene-positive strain showed a different pattern of antibacterial activity. These results speculate that individual S. mutans strains may affect the bacterial composition of dental plaques.
Topics: Amino Acid Sequence; Anti-Bacterial Agents; Antibiosis; Bacteriocins; Gene Expression Regulation, Bacterial; Humans; Microbial Sensitivity Tests; Mutation; Promoter Regions, Genetic; Regulatory Sequences, Nucleic Acid; Streptococcus mutans
PubMed: 34155274
DOI: 10.1038/s41598-021-92370-1 -
MicrobiologyOpen Jul 2020The ability of Streptococcus mutans to persist in a variety of adverse environments and to emerge as a numerically dominant member of stable oral biofilm communities are...
The ability of Streptococcus mutans to persist in a variety of adverse environments and to emerge as a numerically dominant member of stable oral biofilm communities are essential elements for its cariogenicity. The S. mutans Cid/Lrg system has been studied as a key player in the integration of complex environmental signals into regulatory networks that modulate virulence and cell homeostasis. Cid/Lrg has also been shown to be closely associated with metabolic pathways of this organism, due to distinct patterns of cid and lrg expression in response to growth phase and glucose/oxygen levels. In this study, a comparison of cid and lrg promoter regions with conserved CodY (a regulator which responds to starvation stress)-binding motifs revealed the presence of a potential CodY-binding site, which is arranged similarly in both cid and lrg promoters. Electrophoretic mobility shift assays (EMSAs) and promoter reporter assays demonstrated that expression of the cid and lrg operons is directly mediated by the global transcriptional regulator CodY. DNase I footprinting analyses confirmed the predicted binding sequences for CodY in both the cid and the lrg promoter regions. Overexpression of CodY had no obvious effect on lrgAB expression, but deficiency of CodY still affected lrgAB expression in a lytST-overexpressing strain, suggesting that CodY is required for the full regulation of lrgAB by LytST. We also demonstrated that both CodY and CcpA are involved in regulating pyruvate flux and utilization. Collectively, these data show that CodY directly regulates cid and lrg expression, and together with CcpA (previously shown to directly regulate cid and lrg promoters) contributes to coordinating pyruvate uptake and utilization in response to both the external environment and the cellular metabolic status.
Topics: Bacterial Proteins; Biofilms; Dental Caries; Electrophoretic Mobility Shift Assay; Gene Expression Regulation, Bacterial; Promoter Regions, Genetic; Streptococcus mutans; Virulence
PubMed: 32282137
DOI: 10.1002/mbo3.1040 -
MSphere Mar 2021Virulence properties of cariogenic depend on integral membrane proteins. Bacterial cotranslational protein trafficking involves the signal recognition particle (SRP)...
Virulence properties of cariogenic depend on integral membrane proteins. Bacterial cotranslational protein trafficking involves the signal recognition particle (SRP) pathway components Ffh and FtsY, the SecYEG translocon, and YidC chaperone/insertases. Unlike , survives loss of the SRP pathway and has two paralogs. This study characterized YidC1 and YidC2 interactomes to clarify respective functions alone and in concert with the SRP and/or Sec translocon. Western blots of formaldehyde cross-linked or untreated lysates were reacted with anti-Ffh, anti-FtsY, anti-YidC1, or anti-YidC2 antibodies followed by mass spectrometry (MS) analysis of gel-shifted bands. Cross-linked lysates of wild-type and Δ strains were reacted with anti-YidC2-coupled Dynabeads, and cocaptured proteins were identified by MS. Last, YidC1 and YidC2 C-terminal tail-captured proteins were subjected to two-dimensional (2D) difference gel electrophoresis and MS analysis. Direct interactions of putative YidC1 and YidC2 binding partners were confirmed by bacterial two-hybrid assay. Our results suggest YidC2 works preferentially with the SRP pathway, while YidC1 is preferred for SRP-independent Sec translocon-mediated translocation. YidC1 and YidC2 autonomous pathways were also apparent. Two-hybrid assay identified interactions between holotranslocon components SecYEG/YajC and YidC1. Both YidC1 and YidC2 interacted with Ffh, FtsY, and chaperones DnaK and RopA. Putative membrane-localized substrates HlyX, LemA, and SMU_591c interacted with both YidC1 and YidC2. Identification of several Rgp proteins in the YidC1 interactome suggested its involvement in bacitracin resistance, which was decreased in Δ and SRP-deficient mutants. Collectively, YidC1 and YidC2 interactome analyses has further distinguished these paralogs in the Gram-positive bacterium is a prevalent oral pathogen and major causative agent of tooth decay. Many proteins that enable this bacterium to thrive in its environmental niche and cause disease are embedded in its cytoplasmic membrane. The machinery that transports proteins into bacterial membranes differs between Gram-negative and Gram-positive organisms, an important difference being the presence of multiple YidC paralogs in Gram-positive bacteria. Characterization of a protein's interactome can help define its physiological role. Herein, we characterized the interactomes of YidC1 and YidC2. Results demonstrated substantial overlap between their interactomes but also revealed several differences in their direct protein binding partners. Membrane transport machinery components were identified in the context of a large network of proteins involved in replication, transcription, translation, and cell division/cell shape. This information contributes to our understanding of protein transport in Gram-positive bacteria in general and informs our understanding of pathogenesis.
Topics: Bacterial Proteins; Membrane Transport Proteins; Protein Binding; Protein Transport; Streptococcus mutans
PubMed: 33658280
DOI: 10.1128/mSphere.01308-20