{"title":"Molecular and regulatory mechanisms of oxidative stress adaptation in Streptococcus mutans.","authors":"Shuxing Yu, Qizhao Ma, Yuqing Li, Jing Zou","doi":"10.1111/omi.12388","DOIUrl":"https://doi.org/10.1111/omi.12388","url":null,"abstract":"<p><p>Dental caries is a chronic progressive disease, which destructs dental hard tissues under the influence of multiple factors, mainly bacteria. Streptococcus mutans is the main cariogenic bacteria. However, its cariogenic virulence is affected by environmental stress such as oxidative stress, nutrient deficiency, and low pH to some extent. Oxidative stress is one of the main stresses that S. mutans faces in oral cavity. But there are a variety of protective molecules to resist oxidative stress in S. mutans, including superoxide dismutase, nicotinamide adenine dinucleotide oxidase, Dps-like peroxide resistance protein, alkyl-hydrogen peroxide reductase, thioredoxin, glutamate-reducing protein system, and some metabolic substances. Additionally, some transcriptional regulatory factors (SloR, PerR, Rex, Spx, etc.) and two-component systems are also closely related to oxidative stress adaptation by modulating the expression of protective molecules. This review summarizes the research progress of protective molecules and regulatory mechanisms (mainly transcription factors) of oxidative stress adaptation of S. mutans.</p>","PeriodicalId":18815,"journal":{"name":"Molecular Oral Microbiology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10725036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yang Qiu, Xuelian Tan, Zixue Lei, Xuan Chen, Jiamin Chen, Tao Gong, Yajie Wu, Yuqing Li, Dingming Huang
{"title":"A GntR family transcription factor in Porphyromonas gingivalis regulates bacterial growth, acylpeptidyl oligopeptidase, and gingipains activity.","authors":"Yang Qiu, Xuelian Tan, Zixue Lei, Xuan Chen, Jiamin Chen, Tao Gong, Yajie Wu, Yuqing Li, Dingming Huang","doi":"10.1111/omi.12400","DOIUrl":"https://doi.org/10.1111/omi.12400","url":null,"abstract":"<p><p>Porphyromonas gingivalis is a keystone pathogen for periodontitis. The function of the GntR family transcription factor is poorly studied in P. gingivalis. Numerous processes govern bacterial growth. The survival and pathogenicity of P. gingivalis depend heavily on its capacity to acquire amino acids as nutritional sources. In this investigation, a GntR transcription factor, pg1007, was identified in P. gingivalis, the deletion of which significantly inhibited bacterial growth. The mutant strain also exhibited an increased extracellular activity of gingipains and acylpeptidyl oligopeptidase (AOP). Global gene expression profiling revealed that the expression levels of 59 genes were significantly altered in the Δpg1007 mutant, with an upregulation in gene expression for AOP, ABC transporters, and some membrane proteins. In addition, His-PG1007 protein was purified as a recombinant protein from Escherichia coli, and the conserved DNA sequence bound by it was determined using electrophoretic mobility shift assays and DNase I footprinting assays. Consequently, this study demonstrated that pg1007 is a crucial transcription factor in P. gingivalis and regulates the bacterial growth and activity of gingipains and AOP. These findings may enhance our understanding of the regulation of bacterial proliferation and protease activity in P. gingivalis.</p>","PeriodicalId":18815,"journal":{"name":"Molecular Oral Microbiology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10725553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anthony R McLean, Julian Torres-Morales, Floyd E Dewhirst, Gary G Borisy, Jessica L Mark Welch
{"title":"Site-tropism of streptococci in the oral microbiome.","authors":"Anthony R McLean, Julian Torres-Morales, Floyd E Dewhirst, Gary G Borisy, Jessica L Mark Welch","doi":"10.1111/omi.12387","DOIUrl":"10.1111/omi.12387","url":null,"abstract":"<p><p>A detailed understanding of where bacteria localize is necessary to advance microbial ecology and microbiome-based therapeutics. The site-specialist hypothesis predicts that most microbes in the human oral cavity have a primary habitat type within the mouth where they are most abundant. We asked whether this hypothesis accurately describes the distribution of the members of the genus Streptococcus, a clinically relevant taxon that dominates most oral sites. Prior analysis of 16S rRNA gene sequencing data indicated that some oral Streptococcus clades are site-specialists while others may be generalists. However, within complex microbial populations composed of numerous closely related species and strains, such as the oral streptococci, genome-scale analysis is necessary to provide the resolution to discriminate closely related taxa with distinct functional roles. Here, we assess whether individual species within this genus are specialists using publicly available genomic sequence data that provide species-level resolution. We chose a set of high-quality representative genomes for human oral Streptococcus species. Onto these genomes, we mapped shotgun metagenomic sequencing reads from supragingival plaque, tongue dorsum, and other sites in the oral cavity. We found that every abundant Streptococcus species in the healthy human oral cavity showed strong site-tropism and that even closely related species such as S. mitis, S. oralis, and S. infantis specialized in different sites. These findings indicate that closely related bacteria can have distinct habitat distributions in the absence of dispersal limitation and under similar environmental conditions and immune regimes. Substantial overlap between the core genes of these three species suggests that site-specialization is determined by subtle differences in genomic content.</p>","PeriodicalId":18815,"journal":{"name":"Molecular Oral Microbiology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9691528/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9267119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Apoena Aguiar Ribeiro, Yizu Jiao, Mustafa Girnary, Tomaz Alves, Liang Chen, Anna Farrell, Di Wu, Flavia Teles, Naohiro Inohara, Karen V Swanson, Julie T Marchesan
{"title":"Oral biofilm dysbiosis during experimental periodontitis.","authors":"Apoena Aguiar Ribeiro, Yizu Jiao, Mustafa Girnary, Tomaz Alves, Liang Chen, Anna Farrell, Di Wu, Flavia Teles, Naohiro Inohara, Karen V Swanson, Julie T Marchesan","doi":"10.1111/omi.12389","DOIUrl":"10.1111/omi.12389","url":null,"abstract":"<p><strong>Objectives: </strong>We have previously characterized the main osteoimmunological events that occur during ligature periodontitis. This study aims to determine the polymicrobial community shifts that occur during disease development.</p><p><strong>Methods: </strong>Periodontitis was induced in C57BL/6 mice using the ligature-induced periodontitis model. Healthy oral mucosa swabs and ligatures were collected every 3 days from 0 to 18 days post-ligature placement. Biofilm samples were evaluated by 16SrRNA gene sequencing (Illumina MiSeq) and QIIME. Time-course changes were determined by relative abundance, diversity, and rank analyses (PERMANOVA, Bonferroni-adjusted).</p><p><strong>Results: </strong>Microbial differences between health and periodontal inflammation were observed at all phylogenic levels. An evident microbial community shift occurred in 25 genera during the advancement of \"gingivitis\" (3-6 days) to periodontitis (9-18 days). From day 0 to 18, dramatic changes were identified in Streptococcus levels, with an overall decrease (54.04%-0.02%) as well an overall increase of Enterococcus and Lactobacillus (23.7%-73.1% and 10.1%-70.2%, respectively). Alpha-diversity decreased to its lowest at 3 days, followed by an increase in diversity as disease advancement. Beta-diversity increased after ligature placement, indicating that bone loss develops in response to a greater microbial variability (p = 0.001). Levels of facultative and strict anaerobic bacteria augmented over the course of disease progression, with a total of eight species significantly different during the 18-day period.</p><p><strong>Conclusion: </strong>The data supports that murine gingival inflammation and alveolar bone loss develop in response to microbiome shifts. Bacterial diversity increased during progression to bone loss. These findings further support the utilization of the periodontitis ligature model for microbial shift analysis under different experimental conditions.</p>","PeriodicalId":18815,"journal":{"name":"Molecular Oral Microbiology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10034670/pdf/nihms-1872862.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9533033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Electrochemical sensors for oral biofilm-biomaterials interface characterization: A review.","authors":"Dipankar Koley","doi":"10.1111/omi.12396","DOIUrl":"10.1111/omi.12396","url":null,"abstract":"<p><p>Important processes related to the interaction of the oral microbiome with the tooth surface happen directly at the interface. For example, the chemical microenvironment that exists at the interface of microbial biofilms and the native tooth structure is directly involved in caries development. Consequentially, a critical understanding of this interface and its chemical microenvironment would provide novel avenues in caries prevention, including secondary caries that often occurs at the interface of the dental biofilm, tooth structure, and dental material. Electrochemical sensors are a unique quantitative tool and have the inherent advantages of miniaturization, stability, and selectivity. That makes the electrochemical sensors ideal tools for studying these critical biofilm microenvironments with high precision. This review highlights the development and applications of several novel electrochemical sensors such as pH, Ca<sup>2+</sup> , and hydrogen peroxide sensors as scanning electrochemical microscope probes in addition to flexible pH wire sensors for real-time bacterial biofilm-dental surface and dental materials interface studies.</p>","PeriodicalId":18815,"journal":{"name":"Molecular Oral Microbiology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9759506/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10729870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Islam A A Ali, Gary S P Cheung, Prasanna Neelakantan
{"title":"Transition metals and Enterococcus faecalis: Homeostasis, virulence and perspectives.","authors":"Islam A A Ali, Gary S P Cheung, Prasanna Neelakantan","doi":"10.1111/omi.12391","DOIUrl":"https://doi.org/10.1111/omi.12391","url":null,"abstract":"<p><p>Enterococcus faecalis, a Gram-positive bacterium, is known to be a key player in several chronic infections as well as nosocomial, heart valve, urinary tract, surgical wound, and dental root canal infections. The capability to sense different transition metal levels and tune its response accordingly endows it with the potential to thrive and cause infections in several host niches. Over the past decade, our knowledge of how transition metals play a critical role in maintaining homeostasis of E. faecalis has improved significantly. The aim of this review is to elucidate the roles of metals such as iron, manganese, zinc, and copper in the physiology, metabolism, and pathogenicity of E. faecalis. These essential micronutrients contribute to energy production, redox stress response, expression of virulence determinants, and cooperation in polymicrobial communities. The review also highlights metal homeostasis systems in E. faecalis, which respond to fluctuations in extracellular metal levels, and regulate the intracellular metal content. Regulation of intracellular metallome secures the tolerance of E. faecalis to oxidative stress and host-mediated metal sequestration strategies. Therapeutic interventions which deprive E. faecalis of its essential metal requirements or disrupt its homeostatic control have been proposed to combat E. faecalis infections.</p>","PeriodicalId":18815,"journal":{"name":"Molecular Oral Microbiology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40356392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wannes Van Holm, Tim Verspecht, Rita Carvalho, Kristel Bernaerts, Nico Boon, Naiera Zayed, Wim Teughels
{"title":"Glycerol strengthens probiotic effect of Limosilactobacillus reuteri in oral biofilms: A synergistic synbiotic approach.","authors":"Wannes Van Holm, Tim Verspecht, Rita Carvalho, Kristel Bernaerts, Nico Boon, Naiera Zayed, Wim Teughels","doi":"10.1111/omi.12386","DOIUrl":"https://doi.org/10.1111/omi.12386","url":null,"abstract":"<p><p>Both in vitro and in vivo studies have shown that the probiotic Limosilactobacillus reuteri can improve oral health. Limosilactobacillus reuteri species are known to produce the antimicrobial \"reuterin\" from glycerol. In order to further increase its antimicrobial activity, this study evaluated the effect of the combined use of glycerol and Limosilactobacillus reuteri (ATCC PTA 5289) in view of using a synergistic synbiotic over a probiotic. An antagonistic agar growth and a multispecies biofilm model showed that the antimicrobial potential of the probiotic was significantly enhanced against periodontal pathobionts and anaerobic commensals when supplemented with glycerol. Synbiotic biofilms also showed a significant reduction in inflammatory expression of human oral keratinocytes (HOK-18A), but only when the keratinocytes were preincubated with the probiotic. Probiotic preincubation of keratinocytes or probiotic and synbiotic treatment of biofilms alone was insufficient to significantly reduce inflammatory expression. Overall, this study shows that combining glycerol with the probiotic L. reuteri into a synergistic synbiotic can greatly improve the effectiveness of the latter.</p>","PeriodicalId":18815,"journal":{"name":"Molecular Oral Microbiology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33450488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dongyeop Kim, Tatsuro Ito, Anderson Hara, Yong Li, Jens Kreth, Hyun Koo
{"title":"Antagonistic interactions by a high H<sub>2</sub> O<sub>2</sub> -producing commensal streptococcus modulate caries development by Streptococcus mutans.","authors":"Dongyeop Kim, Tatsuro Ito, Anderson Hara, Yong Li, Jens Kreth, Hyun Koo","doi":"10.1111/omi.12394","DOIUrl":"10.1111/omi.12394","url":null,"abstract":"<p><p>Dental caries (tooth-decay) is caused by biofilms harboring polymicrobial communities on teeth that leads to the onset of localized areas of enamel demineralization. Streptococcus mutans has been clinically associated with severe caries in childhood. Although commensal bacteria can combat S. mutans using self-generated antimicrobials such as hydrogen peroxide (H<sub>2</sub> O<sub>2</sub> ), constant sugar-rich diet consumption disrupts microbial homeostasis shifting toward cariogenic community. Recently, Streptococcus oralis subsp. tigurinus strain J22, an oral isolate, was identified as a uniquely potent H<sub>2</sub> O<sub>2</sub> producer. Here, we assess whether a high H<sub>2</sub> O<sub>2</sub> -producing commensal streptococcus can modulate the spatial organization and virulence of S. mutans within biofilms. Using an experimental biofilm model, we find that the presence of S. oralis J22 can effectively inhibit the clustering, accumulation, and spatial organization of S. mutans on ex vivo human tooth surface, resulting in significant reduction of enamel demineralization. Notably, the generation of H<sub>2</sub> O<sub>2</sub> via pyruvate oxidase (SpxB) from S. oralis J22 is not repressed by sugars (a common repressor in other mitis group streptococci), resulting in enhanced inhibition of S. mutans growth (vs. Streptococcus gordonii). We further investigate its impact on biofilm virulence using an in vivo rodent caries model under sugar-rich diet. Coinfection of S. mutans with S. oralis results in reduced caries development compared to either species infected alone, whereas coinfection with S. gordonii has negligible effects, suggesting that the presence of an efficient, high H<sub>2</sub> O<sub>2</sub> -producer can disrupt S. mutans virulence. This work demonstrates that oral isolates with unusual high H<sub>2</sub> O<sub>2</sub> production may be capable of modulating biofilm cariogenicity in vivo. The findings also highlight the importance of bacterial antagonistic interactions within polymicrobial communities in health and in disease-causing state.</p>","PeriodicalId":18815,"journal":{"name":"Molecular Oral Microbiology","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33483114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cover Image, Volume 37, Issue 6","authors":"","doi":"10.1111/omi.12401","DOIUrl":"https://doi.org/10.1111/omi.12401","url":null,"abstract":"The cover image is based on the Original Article <i>Site-tropism of streptococci in the oral microbiome</i> by Anthony R. McLean et al., https://doi.org/10.1111/omi.12387.","PeriodicalId":18815,"journal":{"name":"Molecular Oral Microbiology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138508325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}