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Microbiology Spectrum Oct 2018Bacteria belonging to the genus are the first inhabitants of the oral cavity, which can be acquired right after birth and thus play an important role in the assembly of... (Review)
Review
Bacteria belonging to the genus are the first inhabitants of the oral cavity, which can be acquired right after birth and thus play an important role in the assembly of the oral microbiota. In this article, we discuss the different oral environments inhabited by streptococci and the species that occupy each niche. Special attention is given to the taxonomy of , because this genus is now divided into eight distinct groups, and oral species are found in six of them. Oral streptococci produce an arsenal of adhesive molecules that allow them to efficiently colonize different tissues in the mouth. Also, they have a remarkable ability to metabolize carbohydrates via fermentation, thereby generating acids as byproducts. Excessive acidification of the oral environment by aciduric species such as is directly associated with the development of dental caries. However, less acid-tolerant species such as and produce large amounts of alkali, displaying an important role in the acid-base physiology of the oral cavity. Another important characteristic of certain oral streptococci is their ability to generate hydrogen peroxide that can inhibit the growth of . Thus, oral streptococci can also be beneficial to the host by producing molecules that are inhibitory to pathogenic species. Lastly, commensal and pathogenic streptococci residing in the oral cavity can eventually gain access to the bloodstream and cause systemic infections such as infective endocarditis.
Topics: Carbohydrate Metabolism; Dental Caries; Endocarditis; Fermentation; Humans; Hydrogen Peroxide; Metagenomics; Microbiota; Mouth; Phylogeny; Streptococcus; Streptococcus gordonii; Streptococcus mutans; Streptococcus salivarius
PubMed: 30338752
DOI: 10.1128/microbiolspec.GPP3-0042-2018 -
Microorganisms Nov 2020, a Gram-positive bacterium, is a commensal bacterium that is commonly found in the skin, oral cavity, and intestine. It is also known as an opportunistic pathogen that... (Review)
Review
, a Gram-positive bacterium, is a commensal bacterium that is commonly found in the skin, oral cavity, and intestine. It is also known as an opportunistic pathogen that can cause local or systemic diseases, such as apical periodontitis and infective endocarditis. , an early colonizer, easily attaches to host tissues, including tooth surfaces and heart valves, forming biofilms. penetrates into root canals and blood streams, subsequently interacting with various host immune and non-immune cells. The cell wall components of which include lipoteichoic acids, lipoproteins, serine-rich repeat adhesins, peptidoglycans, and cell wall proteins, are recognizable by individual host receptors. They are involved in virulence and immunoregulatory processes causing host inflammatory responses. Therefore, cell wall components act as virulence factors that often progressively develop diseases through overwhelming host responses. This review provides an overview of and how its cell wall components could contribute to the pathogenesis and development of therapeutic strategies.
PubMed: 33255499
DOI: 10.3390/microorganisms8121852 -
Applied and Environmental Microbiology Oct 2021Cell-cell adhesion between oral bacteria plays a key role in the development of polymicrobial communities such as dental plaque. Oral streptococci such as Streptococcus...
Cell-cell adhesion between oral bacteria plays a key role in the development of polymicrobial communities such as dental plaque. Oral streptococci such as Streptococcus gordonii and Streptococcus oralis are important early colonizers of dental plaque and bind to a wide range of different oral microorganisms, forming multispecies clumps or "coaggregates." S. gordonii actively responds to coaggregation by regulating gene expression. To further understand these responses, we assessed gene regulation in S. gordonii and S. oralis following coaggregation in 25% human saliva. Coaggregates were formed by mixing, and after 30 min, RNA was extracted for dual transcriptome sequencing (RNA-Seq) analysis. In S. oralis, 18 genes (6 upregulated and 12 downregulated) were regulated by coaggregation. Significantly downregulated genes encoded functions such as amino acid and antibiotic biosynthesis, ribosome, and central carbon metabolism. In total, 28 genes were differentially regulated in Streptococcus gordonii (25 upregulated and 3 downregulated). Many genes associated with transporters and a two-component (NisK/SpaK) regulatory system were upregulated following coaggregation. Our comparative analyses of S. gordoniiS. oralis with different previously published S. gordonii pairings (S. gordoniiFusobacterium nucleatum and S. gordoniiVeillonella parvula) suggest that the gene regulation is specific to each pairing, and responses do not appear to be conserved. This ability to distinguish between neighboring bacteria may be important for S. gordonii to adapt appropriately during the development of complex biofilms such as dental plaque. Dental plaque is responsible for two of the most prevalent diseases in humans, dental caries and periodontitis. Controlling the formation of dental plaque and preventing the transition from oral health to disease requires a detailed understanding of microbial colonization and biofilm development. Streptococci are among the most common colonizers of dental plaque. This study identifies key genes that are regulated when oral streptococci bind to one another, as they do in the early stages of dental plaque formation. We show that specific genes are regulated in two different oral streptococci following the formation of mixed-species aggregates. The specific responses of S. gordonii to coaggregation with S. oralis are different from those to coaggregation with other oral bacteria. Targeting the key genes that are upregulated during interspecies interactions may be a powerful approach to control the development of biofilm and maintain oral health.
Topics: Dental Plaque; Humans; RNA-Seq; Streptococcus gordonii; Streptococcus oralis; Transcriptome
PubMed: 34469191
DOI: 10.1128/AEM.01558-21 -
Applied and Environmental Microbiology Dec 2020Amino sugars, particularly glucosamine (GlcN) and -acetylglucosamine (GlcNAc), are abundant carbon and nitrogen sources supplied in host secretions and in the diet to...
Amino sugars, particularly glucosamine (GlcN) and -acetylglucosamine (GlcNAc), are abundant carbon and nitrogen sources supplied in host secretions and in the diet to the biofilms colonizing the human oral cavity. Evidence is emerging that these amino sugars provide ecological advantages to beneficial commensals over oral pathogens and pathobionts. Here, we performed transcriptome analysis on and growing in single-species or dual-species cultures with glucose, GlcN, or GlcNAc as the primary carbohydrate source. Compared to glucose, GlcN caused drastic transcriptomic shifts in each species of bacteria when it was cultured alone. Likewise, cocultivation in the presence of GlcN yielded transcriptomic profiles that were dramatically different from the single-species results from GlcN-grown cells. In contrast, GlcNAc elicited only minor changes in the transcriptome of either organism in single- and dual-species cultures. Interestingly, genes involved in pyruvate metabolism were among the most significantly affected by GlcN in both species, and these changes were consistent with measurements of pyruvate in culture supernatants. Differing from what was found in a previous report, growth of alone with GlcN inhibited the expression of multiple operons required for mutacin production. Cocultivation with consistently increased the expression of two manganese transporter operons ( and ) and decreased expression of mutacin genes in Conversely, appeared to be less affected by the presence of but did show increases in genes for biosynthetic processes in the cocultures. In conclusion, amino sugars profoundly alter the interactions between pathogenic and commensal streptococci by reprogramming central metabolism. Carbohydrate metabolism is central to the development of dental caries. A variety of sugars available to dental microorganisms influence the development of caries by affecting the physiology, ecology, and pathogenic potential of tooth biofilms. Using two well-characterized oral bacteria, one pathogen () and one commensal (), in an RNA deep-sequencing analysis, we studied the impact of two abundant amino sugars on bacterial gene expression and interspecies interactions. The results indicated large-scale remodeling of gene expression induced by GlcN in particular, affecting bacterial energy generation, acid production, protein synthesis, and release of antimicrobial molecules. Our study provides novel insights into how amino sugars modify bacterial behavior, information that will be valuable in the design of new technologies to detect and prevent oral infectious diseases.
Topics: Amino Sugars; Gene Expression; Gene Expression Profiling; Genes, Bacterial; Microbiota; Mouth; Streptococcus gordonii; Streptococcus mutans; Symbiosis
PubMed: 33097515
DOI: 10.1128/AEM.01459-20 -
Frontiers in Cellular and Infection... 2021Interspecies coaggregation promotes transcriptional changes in oral bacteria, affecting bacterial pathogenicity. () and () are common oral inhabitants. The present...
Interspecies coaggregation promotes transcriptional changes in oral bacteria, affecting bacterial pathogenicity. () and () are common oral inhabitants. The present study investigated the transcriptional profiling of and subsp. in response to the dual-species coaggregation using RNA-seq. Macrophages were infected with both species to explore the influence of bacterial coaggregation on both species' abilities to survive within macrophages and induce inflammatory responses. Results indicated that, after the 30-min dual-species coaggregation, 116 genes were significantly up-regulated, and 151 genes were significantly down-regulated in ; 97 genes were significantly down-regulated, and 114 genes were significantly up-regulated in subsp. . Multiple genes were involved in the biosynthesis and export of cell-wall proteins and carbohydrate metabolism. subsp. genes were mostly associated with translation and protein export. The coaggregation led to decreased expression levels of genes associated with lipopolysaccharide and peptidoglycan biosynthesis. Coaggregation between and subsp. significantly promoted both species' intracellular survival within macrophages and attenuated the production of pro-inflammatory cytokines IL-6 and IL-1β. Physical interactions between these two species promoted a symbiotic lifestyle and repressed macrophage's killing and pro-inflammatory responses.
Topics: Bacteria; Bacterial Adhesion; Fusobacterium nucleatum; Immunity; Macrophages; Streptococcus gordonii
PubMed: 35071038
DOI: 10.3389/fcimb.2021.783323 -
Frontiers in Microbiology 2022() is one of the primary pathogens responsible for dental caries. () is one of the early colonizers of dental plaque and can compete with for growth. In the present...
() is one of the primary pathogens responsible for dental caries. () is one of the early colonizers of dental plaque and can compete with for growth. In the present analysis, we explored key target genes against in using 80 clinical isolates with varying capabilities against . A principal coordinate analysis revealed significant genetic diversity differences between antagonistic and non-antagonistic groups. Genomic comparisons revealed 33 and 61 genes that were, respectively, positively and negatively correlated with against , with RNA-sequencing (RNA-seq) highlighting 11 and 43 genes that were, respectively, upregulated and downregulated in the antagonistic group. Through a combination of these results and antiSMASH analysis, we selected 16 genes for qRT-PCR validation in which the expression levels of SMU_137 (malate dehydrogenase, mleS), SMU_138 (malate permease, mleP), SMU_139 (oxalate decarboxylase, oxdC), and SMU_140 (glutathione reductase) were consistent with RNA-seq results. SMU_1315c-1317c (SMU_1315c transport-related gene) and SMU_1908c-1909c were, respectively, downregulated and upregulated in the antagonistic group. The expression patterns of adjacent genes were closely related, with correlation coefficient values greater than 0.9. These data reveal new targets (SMU_137-140, SMU_1315c-1317c, and SMU_1908c-1909c) for investigating the critical gene clusters against in clinical isolates.
PubMed: 36033899
DOI: 10.3389/fmicb.2022.945108 -
Acta Crystallographica. Section D,... Sep 2021Streptococcus gordonii is a member of the viridans streptococci and is an early colonizer of the tooth surface. Adherence to the tooth surface is enabled by proteins...
Streptococcus gordonii is a member of the viridans streptococci and is an early colonizer of the tooth surface. Adherence to the tooth surface is enabled by proteins present on the S. gordonii cell surface, among which SspB belongs to one of the most well studied cell-wall-anchored adhesin families: the antigen I/II (AgI/II) family. The C-terminal region of SspB consists of three tandemly connected individual domains that display the DEv-IgG fold. These C-terminal domains contain a conserved Ca-binding site and isopeptide bonds, and they adhere to glycoprotein 340 (Gp340; also known as salivary agglutinin, SAG). Here, the structural and functional characterization of the C domain at 2.7 Å resolution is reported. Although the individual C-terminal domains of Streptococcus mutans AgI/II and S. gordonii SspB show a high degree of both sequence and structural homology, superposition of these structures highlights substantial differences in their electrostatic surface plots, and this can be attributed to the relative orientation of the individual domains (C, C and C) with respect to each other and could reflect their specificity in binding to extracellular matrix molecules. Studies further confirmed that affinity for Gp340 or its scavenger receptor cysteine-rich (SRCR) domains requires two of the three domains of C, namely C or C, which is different from AgI/II. Using protein-protein docking studies, models for this observed functional difference between C and C in their binding to SRCR are presented.
Topics: Adhesins, Bacterial; Amino Acid Sequence; Bacterial Proteins; Binding Sites; Humans; Streptococcal Infections; Streptococcus gordonii; Streptococcus mutans; Structure-Activity Relationship
PubMed: 34473090
DOI: 10.1107/S2059798321008135 -
IDCases 2023Empyema is often caused by species, followed by . The organism belongs to the group, which rarely causes empyema. We report the case of a 59-year-old man who...
Empyema is often caused by species, followed by . The organism belongs to the group, which rarely causes empyema. We report the case of a 59-year-old man who presented with exertional dyspnea and chest pain on the right side. The image obtained showed effusion on the right side. was recovered from purulent pleural effusion culture. The patient underwent video-assisted thoracoscopic surgery with decortication, pneumolysis and received antibiotics for 13 days. A total of seven cases were analyzed after combining six cases in the literature and our presented case. The majority of empyema patients were male (six patients, 86%) and empyema on the right side (five patients, 71%). Common risk factors included poor dental hygiene or recent dental procedure (three patients, 43%), diabetes mellitus (three patients, 43%), and smoking (three patients, 43%). Only a few cases developed empyema-related complications, including bacteremia (one patient, 14%) and spleen abscesses (one patient, 14%). Most patients underwent chest tube insertion (seven patients, 100%) and survived without recurrent empyema (six patients, 86%).
PubMed: 36704022
DOI: 10.1016/j.idcr.2023.e01693 -
AMB Express Dec 2022Streptococcus mutans, whose main virulence factor is glucosyltransferase (Gtf), has a substantial impact on the development of dental caries. S. mutans membrane vesicles...
Streptococcus mutans, whose main virulence factor is glucosyltransferase (Gtf), has a substantial impact on the development of dental caries. S. mutans membrane vesicles (MVs), which are rich in Gtfs, have been shown to affect biofilm formation of other microorganisms. Streptococcus gordonii and Streptococcus sanguinis are initial colonizers of tooth surfaces, which provide attachment sites for subsequent microorganisms and are crucial in the development of oral biofilms. S. mutans and S. gordonii, as well as S. mutans and S. sanguinis, have a complex competitive and cooperative relationship, but it is unclear whether S. mutans MVs play a role in these interspecific interactions. Therefore, we co-cultured S. mutans MVs, having or lacking Gtfs, with S. gordonii and S. sanguinis. Our results showed that S. mutans MVs inhibited biofilm formation of S. gordonii and S. sanguinis but did not affect their planktonic growth; contrastingly, S. mutans ΔgtfBC mutant MVs had little effect on both their growth and biofilm formation. Additionally, there were fewer and more dispersed bacteria in the biofilms of the S. mutans MV-treated group than that in the control group. Furthermore, the expression levels of the biofilm-related virulence factors GtfG, GtfP, and SpxB in S. gordonii and S. sanguinis were significantly downregulated in response to S. mutans MVs. In conclusion, the results of our study showed that S. mutans MVs inhibited biofilm formation of S. gordonii and S. sanguinis, revealing an important role for MVs in interspecific interactions.
PubMed: 36508003
DOI: 10.1186/s13568-022-01499-3 -
International Journal of Oral Science Mar 2012Protein phosphorylation on tyrosine has emerged as a key device in the control of numerous cellular functions in bacteria. In this article, we review the structure and... (Review)
Review
Protein phosphorylation on tyrosine has emerged as a key device in the control of numerous cellular functions in bacteria. In this article, we review the structure and function of bacterial tyrosine kinases and phosphatases. Phosphorylation is catalyzed by autophosphorylating adenosine triphosphate-dependent enzymes (bacterial tyrosine (BY) kinases) that are characterized by the presence of Walker motifs. The reverse reaction is catalyzed by three classes of enzymes: the eukaryotic-like phosphatases (PTPs) and dual-specific phosphatases; the low molecular weight protein-tyrosine phosphatases (LMW-PTPs); and the polymerase-histidinol phosphatases (PHP). Many BY kinases and tyrosine phosphatases can utilize host cell proteins as substrates, thereby contributing to bacterial pathogenicity. Bacterial tyrosine phosphorylation/dephosphorylation is also involved in biofilm formation and community development. The Porphyromonas gingivalis tyrosine phosphatase Ltp1 is involved in a restraint pathway that regulates heterotypic community development with Streptococcus gordonii. Ltp1 is upregulated by contact with S. gordonii and Ltp1 activity controls adhesin expression and levels of the interspecies signal AI-2.
Topics: Bacteria; Bacterial Proteins; Biofilms; Gene Expression Regulation, Bacterial; Host-Pathogen Interactions; Phosphorylation; Polysaccharides, Bacterial; Porphyromonas gingivalis; Protein Processing, Post-Translational; Protein Structure, Tertiary; Protein Tyrosine Phosphatases; Protein-Tyrosine Kinases; Quorum Sensing; Signal Transduction; Streptococcus gordonii; Virulence Factors
PubMed: 22388693
DOI: 10.1038/ijos.2012.6