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Arbulu S, Kjos M. Revisiting the Multifaceted Roles of Bacteriocins : The Multifaceted Roles of Bacteriocins. MICROBIAL ECOLOGY 2024; 87:41. [PMID: 38351266 PMCID: PMC10864542 DOI: 10.1007/s00248-024-02357-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/01/2024] [Indexed: 02/16/2024]
Abstract
Bacteriocins are gene-encoded antimicrobial peptides produced by bacteria. These peptides are heterogeneous in terms of structure, antimicrobial activities, biosynthetic clusters, and regulatory mechanisms. Bacteriocins are widespread in nature and may contribute to microbial diversity due to their capacity to target specific bacteria. Primarily studied as food preservatives and therapeutic agents, their function in natural settings is however less known. This review emphasizes the ecological significance of bacteriocins as multifunctional peptides by exploring bacteriocin distribution, mobility, and their impact on bacterial population dynamics and biofilms.
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Affiliation(s)
- Sara Arbulu
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
| | - Morten Kjos
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
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2
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Sukumar S, Wang F, Simpson CA, Willet CE, Chew T, Hughes TE, Bockmann MR, Sadsad R, Martin FE, Lydecker HW, Browne GV, Davis KM, Bui M, Martinez E, Adler CJ. Development of the oral resistome during the first decade of life. Nat Commun 2023; 14:1291. [PMID: 36894532 PMCID: PMC9998430 DOI: 10.1038/s41467-023-36781-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 02/10/2023] [Indexed: 03/11/2023] Open
Abstract
Antibiotic overuse has promoted the spread of antimicrobial resistance (AMR) with significant health and economic consequences. Genome sequencing reveals the widespread presence of antimicrobial resistance genes (ARGs) in diverse microbial environments. Hence, surveillance of resistance reservoirs, like the rarely explored oral microbiome, is necessary to combat AMR. Here, we characterise the development of the paediatric oral resistome and investigate its role in dental caries in 221 twin children (124 females and 97 males) sampled at three time points over the first decade of life. From 530 oral metagenomes, we identify 309 ARGs, which significantly cluster by age, with host genetic effects detected from infancy onwards. Our results suggest potential mobilisation of ARGs increases with age as the AMR associated mobile genetic element, Tn916 transposase was co-located with more species and ARGs in older children. We find a depletion of ARGs and species in dental caries compared to health. This trend reverses in restored teeth. Here we show the paediatric oral resistome is an inherent and dynamic component of the oral microbiome, with a potential role in transmission of AMR and dysbiosis.
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Affiliation(s)
- Smitha Sukumar
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
| | - Fang Wang
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Carra A Simpson
- The Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, US
| | - Cali E Willet
- Sydney Informatics Hub, Core Research Facilities, The University of Sydney, Sydney, NSW, Australia
| | - Tracy Chew
- Sydney Informatics Hub, Core Research Facilities, The University of Sydney, Sydney, NSW, Australia
| | - Toby E Hughes
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Adelaide Dental School, University of Adelaide, Adelaide, SA, Australia
| | | | - Rosemarie Sadsad
- Sydney Informatics Hub, Core Research Facilities, The University of Sydney, Sydney, NSW, Australia
| | - F Elizabeth Martin
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Henry W Lydecker
- Sydney Informatics Hub, Core Research Facilities, The University of Sydney, Sydney, NSW, Australia
| | - Gina V Browne
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Institute of Dental Research, Westmead Centre for Oral Health, Westmead, NSW, Australia
| | - Kylie M Davis
- Adelaide Dental School, University of Adelaide, Adelaide, SA, Australia
| | - Minh Bui
- Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Elena Martinez
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Sydney, NSW, Australia
| | - Christina J Adler
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia.
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3
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Jiang W, Xie Z, Huang S, Huang Q, Chen L, Gao X, Lin Z. Targeting cariogenic pathogens and promoting competitiveness of commensal bacteria with a novel pH-responsive antimicrobial peptide. J Oral Microbiol 2022; 15:2159375. [PMID: 36570976 PMCID: PMC9788686 DOI: 10.1080/20002297.2022.2159375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Novel ecological antimicrobial approaches to dental caries focus on inhibiting cariogenic pathogens while enhancing the growth of health-associated commensal communities or suppressing cariogenic virulence without affecting the diversity of oral microbiota, which emphasize the crucial role of establishing a healthy microbiome in caries prevention. Considering that the acidified cariogenic microenvironment leads to the dysbiosis of microecology and demineralization of enamel, exploiting the acidic pH as a bioresponsive trigger to help materials and medications target cariogenic pathogens is a promising strategy to develop novel anticaries approaches. In this study, a pH-responsive antimicrobial peptide, LH12, was designed utilizing the pH-sensitivity of histidine, which showed higher cationicity and stronger interactions with bacterial cytomembranes at acidic pH. Streptococcus mutans was used as the in vitro caries model to evaluate the inhibitory effects of LH12 on the cariogenic properties, such as biofilm formation, biofilm morphology, acidurance, acidogenicity, and exopolysaccharides synthesis. The dual-species model of Streptococcus mutans and Streptococcus gordonii was established in vitro to evaluate the regulation effects of LH12 on the mixed species microbial community containing both cariogenic bacteria and commensal bacteria. LH12 suppressed the cariogenic properties and regulated the bacterial composition to a healthier condition through a dual-functional mechanism. Firstly, LH12-targeted cariogenic pathogens in response to the acidified microenvironment and suppressed the cariogenic virulence by inhibiting the expression of multiple virulence genes and two-component signal transduction systems. Additionally, LH12 elevated H2O2 production of the commensal bacteria and subsequently improved the ecological competitiveness of the commensals. The dual-functional mechanism made LH12 a potential bioresponsive approach to caries management.
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Affiliation(s)
- Wentao Jiang
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, GuangdongChina
| | - Zhuo Xie
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, GuangdongChina
| | - Shuheng Huang
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, GuangdongChina
| | - Qiting Huang
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, GuangdongChina
| | - Lingling Chen
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, GuangdongChina
| | - Xianling Gao
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, GuangdongChina
| | - Zhengmei Lin
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, GuangdongChina,CONTACT Zhengmei Lin Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong510055, China
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4
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Liu Y, Wang Z, Zhou Z, Ma Q, Li J, Huang J, Lei L, Zhou X, Cheng L, Zou J, Ren B. Candida albicans CHK1 gene regulates its cross-kingdom interactions with Streptococcus mutans to promote caries. Appl Microbiol Biotechnol 2022; 106:7251-7263. [PMID: 36195704 DOI: 10.1007/s00253-022-12211-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/08/2022] [Accepted: 09/24/2022] [Indexed: 01/14/2023]
Abstract
The cross-kingdom interactions between Candida albicans and Streptococcus mutans have played important roles in early childhood caries (ECC). However, the key pathways of C. albicans promoting the cariogenicity of S. mutans are still unclear. Here, we found that C. albicans CHK1 gene was highly upregulated in their dual-species biofilms. C. albicans chk1Δ/Δ significantly reduced the synergistical growth promotion, biofilm formation, and exopolysaccharides (EPS) production of S. mutans, the key cariogenic agent, compared to C. albicans wild type (WT) and CHK1 complementary strains. C. albicans WT upregulated the expressions of S. mutans EPS biosynthesis genes gtfB, gtfC, and gtfD, and their regulatory genes vicR and vicK, but chk1Δ/Δ had no effects. Both C. albicans WT and chk1Δ/Δ failed to promote the biofilm formation and EPS production of S. mutans ΔvicK and antisense-vicR strains, indicating that C. albicans CHK1 upregulated S. mutans vicR and vicK to increase the EPS biosynthesis gene expression, then enhanced the EPS production and biofilm formation to promote the cariogenicity. In rat caries model, the coinfection with chk1Δ/Δ and S. mutans decreased the colonization of S. mutans and developed less caries especially the severe caries compared to that from the combinations of S. mutans with C. albicans WT, indicating the essential role of C. albicans CHK1 gene in the development of dental caries. Our study for the first time demonstrated the key roles of C. albicans CHK1 gene in dental caries and suggested that it may be a practical target to reduce or treat ECC. KEY POINTS: • C. albicans CHK1 gene is important for its interaction with S. mutans. • CHK1 regulates S. mutans two-component system to promote its cariogenicity. • CHK1 gene regulates the cariogenicity of S. mutans in rat dental caries.
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Affiliation(s)
- Yaqi Liu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, 610041, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - Zheng Wang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, 610041, China.,Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Ziyi Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, 610041, China.,Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Qizhao Ma
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, 610041, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - Jing Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, 610041, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - Jun Huang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, 610041, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - Lei Lei
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, 610041, China.,Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, 610041, China.,Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Lei Cheng
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, 610041, China.,Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Jing Zou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, 610041, China. .,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
| | - Biao Ren
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, 610041, China.
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5
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Oliveira LT, Alves LA, Harth-Chu EN, Nomura R, Nakano K, Mattos-Graner RO. VicRK and CovR polymorphisms in Streptococcus mutans strains associated with cardiovascular infections. J Med Microbiol 2021; 70. [PMID: 34939562 DOI: 10.1099/jmm.0.001457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Introduction. Streptococcus mutans, a common species of the oral microbiome, expresses virulence genes promoting cariogenic dental biofilms, persistence in the bloodstream and cardiovascular infections.Gap statement. Virulence gene expression is variable among S. mutans strains and controlled by the transcription regulatory systems VicRK and CovR.Aim. This study investigates polymorphisms in the vicRK and covR loci in S. mutans strains isolated from the oral cavity or from the bloodstream, which were shown to differ in expression of covR, vicRK and downstream genes.Methodology. The transcriptional activities of covR, vicR and vicK were compared by RT-qPCR between blood and oral strains after exposure to human serum. PCR-amplified promoter and/or coding regions of covR and vicRK of 18 strains (11 oral and 7 blood) were sequenced and compared to the reference strain UA159.Results. Serum exposure significantly reduced covR and vicR/K transcript levels in most strains (P<0.05), but reductions were higher in oral than in blood strains. Single-nucleotide polymorphisms (SNPs) were detected in covR regulatory and coding regions, but SNPs affecting the CovR effector domain were only present in two blood strains. Although vicR was highly conserved, vicK showed several SNPs, and SNPs affecting VicK regions important for autokinase activity were found in three blood strains.Conclusions. This study reveals transcriptional and structural diversity in covR and vicR/K, and identifies polymorphisms of functional relevance in blood strains, indicating that covR and vicRK might be important loci for S. mutans adaptation to host selective pressures associated with virulence diversity.
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Affiliation(s)
- Letícia T Oliveira
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Lívia A Alves
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Erika N Harth-Chu
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Ryota Nomura
- Department of Pediatric Dentistry, Osaka University, Graduate School of Dentistry, Osaka, Japan
| | - Kazuhiko Nakano
- Department of Pediatric Dentistry, Osaka University, Graduate School of Dentistry, Osaka, Japan
| | - Renata O Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
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6
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The vicK gene of Streptococcus mutans mediates its cariogenicity via exopolysaccharides metabolism. Int J Oral Sci 2021; 13:45. [PMID: 34916484 PMCID: PMC8677823 DOI: 10.1038/s41368-021-00149-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 07/01/2021] [Accepted: 10/25/2021] [Indexed: 02/05/2023] Open
Abstract
Streptococcus 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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7
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徐 丽, 刘 姗, 王 敏, 刘 芳, 张 容, 张 凯. [Regulatory role of small RNA srn821978 in mutacin IV expression in Streptococcus mutans]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2021; 41:1725-1732. [PMID: 34916201 PMCID: PMC8685694 DOI: 10.12122/j.issn.1673-4254.2021.11.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Indexed: 06/14/2023]
Abstract
OBJECTIVE To analyze the role of small RNA srn821798 in posttranscriptional regulation of mutacin IV expression in Streptococcus mutans. METHODS The potential target genes of srn821978 were predicted using RNAhybrid, RNAPredator and IntaRNA. We collected 10 Streptococcus mutans (S.muans) strains with high expression of mutacin IV and another 10 S.muans strains that did not express mutacin IV screened by inhibition zone test, and the expression levels of srn821798 and the candidate target genes in these strains were detected by qPCR. Using synthesized mimics and inhibitors of srn821798, we constructed S.muans strains with high or low srn821798 expression via electroporation based on the standard strain of S.muans UA159, and analyzed the expression levels of srn821798 and its candidate target genes in these strains. We also examined the binding ability of srn821798 to its target gene sepM using electrophoresis and a dual- luciferase reporter system. RESULTS The expression levels of the candidate target genes of srn821798 including sepM, comD, comE, nlmA and nlmB were significantly higher while the expression level of srn821798 was significantly lower in clinical S.muans strains with high expression of mutacin IV than in those without mutacin IV expression (P < 0.05). Although the expression levels of the candidate target genes in strains with up- regulated or down- regulated srn821798 expression did not differ significantly from those in the standard strain, the expression level of sepM showed a trend of differential distribution, and srn821798 was predicted to have a strong binding ability to sepM action site. CONCLUSION srn821798 may play a regulatory role in the expression of mutacin IV in S.muans, but the underlying mechanism remains to be explored.
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Affiliation(s)
- 丽 徐
- 蚌埠医学院第一附属医院口腔科,安徽 蚌埠 233004Department of Stomatology, First Affiliated Hospital of Bengbu Medical College, Bengbu233004, China
| | - 姗姗 刘
- 蚌埠医学院第一附属医院口腔科,安徽 蚌埠 233004Department of Stomatology, First Affiliated Hospital of Bengbu Medical College, Bengbu233004, China
| | - 敏 王
- 蚌埠医学院第二附属医院口腔科,安徽 蚌埠 233040Department of Stomatology, Second Affiliated Hospital of Bengbu Medical College, Bengbu233040, China
| | - 芳 刘
- 蚌埠医学院第一附属医院口腔科,安徽 蚌埠 233004Department of Stomatology, First Affiliated Hospital of Bengbu Medical College, Bengbu233004, China
| | - 容秀 张
- 蚌埠医学院第一附属医院口腔科,安徽 蚌埠 233004Department of Stomatology, First Affiliated Hospital of Bengbu Medical College, Bengbu233004, China
| | - 凯 张
- 蚌埠医学院第一附属医院口腔科,安徽 蚌埠 233004Department of Stomatology, First Affiliated Hospital of Bengbu Medical College, Bengbu233004, China
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8
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Oogai Y, Nakata M. Small regulatory RNAs of oral streptococci and periodontal bacteria. JAPANESE DENTAL SCIENCE REVIEW 2021; 57:209-216. [PMID: 34745393 PMCID: PMC8551640 DOI: 10.1016/j.jdsr.2021.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/20/2021] [Accepted: 09/24/2021] [Indexed: 11/27/2022] Open
Abstract
Small regulatory RNAs (sRNAs) belong to a family of non-coding RNAs, and many of which regulate expression of genes via interaction with mRNA. The recent popularity of high-throughput next generation sequencers have presented abundant sRNA-related data, including sRNAs of several different oral bacterial species. Some sRNA candidates have been validated in terms of their expression and interaction with target mRNAs. Since the oral cavity is an environment constantly exposed to various stimuli, such as fluctuations in temperature and pH, and osmotic pressure, as well as changes in nutrient availability, oral bacteria require rapid control of gene expression for adaptation to such diverse conditions, while regulation via interactions of sRNAs with mRNA provides advantages for rapid adaptation. This review summarizes methods effective for identification and validation of sRNAs, as well as sRNAs identified to be associated with oral bacterial species, including cariogenic and periodontal pathogens, together with their confirmed and putative target genes.
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Affiliation(s)
- Yuichi Oogai
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, 890-8544, Japan
| | - Masanobu Nakata
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, 890-8544, Japan
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Watanabe A, Kawada-Matsuo M, Le MNT, Hisatsune J, Oogai Y, Nakano Y, Nakata M, Miyawaki S, Sugai M, Komatsuzawa H. Comprehensive analysis of bacteriocins in Streptococcus mutans. Sci Rep 2021; 11:12963. [PMID: 34155274 PMCID: PMC8217173 DOI: 10.1038/s41598-021-92370-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 06/07/2021] [Indexed: 12/24/2022] Open
Abstract
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.
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Affiliation(s)
- Atsuko Watanabe
- Department of Orthodontics and Dentofacial Orthopedics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Miki Kawada-Matsuo
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Kasumi 1-2-3, Hiroshima City, Hiroshima, 734-8551, Japan.,Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan
| | - Mi Nguyen-Tra Le
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Kasumi 1-2-3, Hiroshima City, Hiroshima, 734-8551, Japan.,Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan
| | - Junzo Hisatsune
- Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan.,Antimicrobial Resistance Research Centre, National Institute of Infectious Diseases, Higashi Murayama, Japan
| | - Yuichi Oogai
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yoshio Nakano
- Department of Chemistry, Nihon University School of Dentistry, Tokyo, Japan
| | - Masanobu Nakata
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Shouichi Miyawaki
- Department of Orthodontics and Dentofacial Orthopedics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Motoyuki Sugai
- Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan.,Antimicrobial Resistance Research Centre, National Institute of Infectious Diseases, Higashi Murayama, Japan
| | - Hitoshi Komatsuzawa
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Kasumi 1-2-3, Hiroshima City, Hiroshima, 734-8551, Japan. .,Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan.
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10
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Pei X, Liu M, Zhou H, Fan H. Screening for phagocytosis resistance-related genes via a transposon mutant library of Streptococcus suis serotype 2. Virulence 2021; 11:825-838. [PMID: 32614642 PMCID: PMC7567436 DOI: 10.1080/21505594.2020.1782088] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Streptococcus suis serotype 2 (SS2) is a serious zoonotic pathogen which causes symptoms of streptococcal toxic shock syndrome (STSS) and septicemia; these symptoms suggest that SS2 may have evade innate immunity. Phagocytosis is an important innate immunity process where phagocytosed pathogens are killed by lysosome enzymes, reactive oxygen, and nitrogen species, and acidic environments in macrophages following engulfment. A previously constructed mutant SS2 library was screened, revealing 13 mutant strains with decreased phagocytic resistance. Through inverse PCR, the transposon insertion sites were determined. Through bioinformatic analysis, the 13 disrupted genes were identified as Cps2F, 3 genes belonging to ABC transporters, WalR, TehB, rpiA, S-transferase encoding gene, prs, HsdM, GNAT family N-acetyltransferase encoding gene, proB, and upstream region of DnaK. Except for the capsular polysaccharide biosynthesis associated Cps2F, the other genes had not been linked to a role in anti-phagocytosis. The survival ability in macrophages and whole blood of randomly picked mutant strains were significantly impaired compared with wild-type ZY05719. The virulence of the mutant strains was also attenuated in a mouse infection model. In the WalR mutant, the transcription of HP1065 decreased significantly compared with wild-type strain, indicating WalR might regulated HP1065 expression and contribute to the anti-phagocytosis of SS2. In conclusion, we identified 13 genes that influenced the phagocytosis resistant ability of SS2, and many of these genes have not been reported to be associated with resistance to phagocytosis. Our work provides novel insight into resistance to phagocytosis, and furthers our understanding of the pathogenesis mechanism of SS2.
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Affiliation(s)
- Xiaomeng Pei
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China
| | - Mingxing Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China
| | - Hong Zhou
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China
| | - Hongjie Fan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University , Yangzhou, China
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11
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Modulation of quorum sensing-associated virulence in bacteria: carbohydrate as a key factor. Arch Microbiol 2021; 203:1881-1890. [PMID: 33641039 DOI: 10.1007/s00203-021-02235-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 12/11/2020] [Accepted: 02/11/2021] [Indexed: 01/21/2023]
Abstract
Quorum sensing (QS) is a method of inter-cellular communication that permits bacteria to dispense information about cell density and to synchronize the gene expression accordingly. Gram-positive and Gram-negative bacteria utilize distinct quorum sensing mechanisms for effective pathogenesis. Virulence factor production by pathogenic bacteria is one of the important traits that is under the control of QS. A growing body of evidence has indicated the role of the nutritional environment notably by carbohydrates in dictating the QS-associated virulence gene regulation. The modulation of QS by carbohydrates mitigates the survival and establishment of the pathogen within its host which in turn leads to an increase in morbidity and mortality. This mini-review throws light on the predilection of pathogenic bacteria to rapidly regulate its QS-linked virulence gene expression based on the changing nutrient levels that assist them in prospering within diverse niches.
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12
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Ishkov IP, Kaspar JR, Hagen SJ. Spatial Correlations and Distribution of Competence Gene Expression in Biofilms of Streptococcus mutans. Front Microbiol 2021; 11:627992. [PMID: 33510740 PMCID: PMC7835332 DOI: 10.3389/fmicb.2020.627992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/17/2020] [Indexed: 11/13/2022] Open
Abstract
Streptococcus mutans is an important pathogen in the human oral biofilm. It expresses virulent behaviors that are linked to its genetic competence regulon, which is controlled by comX. Expression of comX is modulated by two diffusible signaling peptides, denoted CSP and XIP, and by other environmental cues such as pH and oxidative stress. The sensitivity of S. mutans competence to environmental inputs that may vary on microscopic length scales raises the question of whether the biofilm environment creates microniches where competence and related phenotypes are concentrated, leading to spatial clustering of S. mutans virulence behaviors. We have used two-photon microscopy to characterize the spatial distribution of comX expression among individual S. mutans cells in biofilms. By analyzing correlations in comX activity, we test for spatial clustering that may suggest localized competence microenvironments. Our data indicate that both competence-signaling peptides diffuse efficiently through the biofilm. XIP elicits a population-wide response. CSP triggers a Poisson-like, spatially random comX response from a subpopulation of cells that is homogeneously dispersed. Our data indicate that competence microenvironments if they exist are small enough that the phenotypes of individual cells are not clustered or correlated to any greater extent than occurs in planktonic cultures.
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Affiliation(s)
- Ivan P Ishkov
- Department of Physics, University of Florida, Gainesville, FL, United States
| | - Justin R Kaspar
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, United States
| | - Stephen J Hagen
- Department of Physics, University of Florida, Gainesville, FL, United States
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13
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Priya A, Kumar CBM, Valliammai A, Selvaraj A, Pandian SK. Usnic acid deteriorates acidogenicity, acidurance and glucose metabolism of Streptococcus mutans through downregulation of two-component signal transduction systems. Sci Rep 2021; 11:1374. [PMID: 33446778 PMCID: PMC7809355 DOI: 10.1038/s41598-020-80338-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/21/2020] [Indexed: 12/19/2022] Open
Abstract
The principal etiological agent of human dental caries, Streptococcus mutans is a multi-virulent pathogen that can transform commensal oral microbial community to plaque biofilms. Major virulence factors that are associated with the cariogenicity of S. mutans include adhesion, acidogenicity and acidurity. All these pathogenic traits coordinate and alter the dental plaque ecology which provide room for interaction with other similar acidogenic and aciduric bacteria. This cariogenic flora increases the possibility of enamel demineralization which headway to caries development. The present study was aimed at evaluating the antimicrobial and antiinfective potential of a lichen secondary metabolite usnic acid (UA) against S. mutans. Minimum inhibitory concentration (MIC), Minimum bactericidal concentration (MBC) and growth kinetics were evaluated to determine the antimicrobial potential of UA against S. mutans. UA at 5 µg mL-1 and 10 µg mL-1 concentration were considered as MIC and MBC respectively. Effect on biofilm formation was microscopically assessed and found to be reduced in a concentration dependent manner. Gene expression of gtfB, gtfC, gtfD, vicR, ComDE and smu0630 was found to be downregulated upon treatment with sub-MIC of UA. Acidogenicity, acidurity, eDNA synthesis and response to oxidative stress were found to be attenuated by the influence of UA. It was also demonstrated to act on preformed mature biofilm of S. mutans. Moreover, UA was shown to possess very low frequency to acquire spontaneous resistance development in S. mutans. Besides, no morphological aberrations or toxic effect was instigated by UA in the human buccal epithelial cells as well as to the oral commensals. Altogether, these results demonstrate the therapeutic potential of usnic acid in the treatment of S. mutans infection.
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Affiliation(s)
- Arumugam Priya
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamil Nadu, 630003, India
| | - Chandra Bose Manish Kumar
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamil Nadu, 630003, India
| | - Alaguvel Valliammai
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamil Nadu, 630003, India
| | - Anthonymuthu Selvaraj
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamil Nadu, 630003, India
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Veschetti L, Sandri A, Patuzzo C, Melotti P, Malerba G, Lleò MM. Mobilome Analysis of Achromobacter spp. Isolates from Chronic and Occasional Lung Infection in Cystic Fibrosis Patients. Microorganisms 2021; 9:microorganisms9010130. [PMID: 33430044 PMCID: PMC7826576 DOI: 10.3390/microorganisms9010130] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/23/2020] [Accepted: 01/04/2021] [Indexed: 12/22/2022] Open
Abstract
Achromobacter spp. is an opportunistic pathogen that can cause lung infections in patients with cystic fibrosis (CF). Although a variety of mobile genetic elements (MGEs) carrying antimicrobial resistance genes have been identified in clinical isolates, little is known about the contribution of Achromobacter spp. mobilome to its pathogenicity. To provide new insights, we performed bioinformatic analyses of 54 whole genome sequences and investigated the presence of phages, insertion sequences (ISs), and integrative and conjugative elements (ICEs). Most of the detected phages were previously described in other pathogens and carried type II toxin-antitoxin systems as well as other pathogenic genes. Interestingly, the partial sequence of phage Bcep176 was found in all the analyzed Achromobacter xylosoxidans genome sequences, suggesting the integration of this phage in an ancestor strain. A wide variety of IS was also identified either inside of or in proximity to pathogenicity islands. Finally, ICEs carrying pathogenic genes were found to be widespread among our isolates and seemed to be involved in transfer events within the CF lung. These results highlight the contribution of MGEs to the pathogenicity of Achromobacter species, their potential to become antimicrobial targets, and the need for further studies to better elucidate their clinical impact.
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Affiliation(s)
- Laura Veschetti
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (L.V.); (C.P.); (G.M.)
| | - Angela Sandri
- Department of Diagnostics and Public Health, Microbiology Section, University of Verona, 37134 Verona, Italy;
| | - Cristina Patuzzo
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (L.V.); (C.P.); (G.M.)
| | - Paola Melotti
- Cystic Fibrosis Center, Azienda Ospedaliera Universitaria Integrata Verona, 37126 Verona, Italy;
| | - Giovanni Malerba
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (L.V.); (C.P.); (G.M.)
| | - Maria M. Lleò
- Department of Diagnostics and Public Health, Microbiology Section, University of Verona, 37134 Verona, Italy;
- Correspondence:
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Amino Sugars Reshape Interactions between Streptococcus mutans and Streptococcus gordonii. Appl Environ Microbiol 2020; 87:AEM.01459-20. [PMID: 33097515 DOI: 10.1128/aem.01459-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 10/13/2020] [Indexed: 12/19/2022] Open
Abstract
Amino sugars, particularly glucosamine (GlcN) and N-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 Streptococcus mutans and Streptococcus gordonii 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 S. mutans alone with GlcN inhibited the expression of multiple operons required for mutacin production. Cocultivation with S. gordonii consistently increased the expression of two manganese transporter operons (slo and mntH) and decreased expression of mutacin genes in S. mutans Conversely, S. gordonii appeared to be less affected by the presence of S. mutans 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.IMPORTANCE 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 (Streptococcus mutans) and one commensal (Streptococcus gordonii), 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.
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16
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Genetic and physiological effects of subinhibitory concentrations of oral antimicrobial agents on Streptococcus mutans biofilms. Microb Pathog 2020; 150:104669. [PMID: 33278519 DOI: 10.1016/j.micpath.2020.104669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 08/01/2020] [Accepted: 11/26/2020] [Indexed: 11/22/2022]
Abstract
Streptococcus mutans is the main etiological agent of dental caries because of its capacity to adhere to enamel structure and form biofilms. This study aimed to evaluate the effects of the anticariogenic agents - sodium fluoride (NaF) and chlorhexidine (CHX) - at levels below minimum inhibitory concentrations (sub-MICs) on the growth of planktonic cells and biofilms and on the expression of vicR and covR genes associated with the regulation of biofilm formation. MICs and minimum bactericidal concentrations (MBCs) of NaF and CHX were determined for S. mutans strains ATCC25175, UA159 and 3VF2. Growth curves were constructed for planktonic cells cultured in brain heart infusion (BHI) broth supplemented with NaF (0.125-0.75MIC) or CHX (0.25-0.75MIC). Biofilm formation assays were performed in microplates containing CHX or NaF at 0.5-1.0MIC and stained with violet crystal. Quantitative polymerase chain reaction determined the alterations in covR and vicR expression in cells exposed to antimicrobials at sub-MIC levels. NaF and CHX at sub-MIC levels affected the growth of planktonic cells of all three S. mutans strains, depending on the concentration tested. The biofilm formation in UA159 and 3VF2 was reduced by NaF at concentrations ≥0.5 MIC, while that of ATCC 25175 was reduced significantly irrespective of dose. In contrast, UA159 and 3VF2 biofilms were not affected by CHX at these levels, whereas those of ATCC 25175 were reduced significantly at all concentrations tested. Under sub-MIC conditions, CHX and (to a lesser degree) NaF increased vicR and covR expression in all three strains, although there were large differences between strains and treatment conditions employed. CHX and NaF at sub-MIC levels influence on the growth of S. mutans in planktonic and biofilm conditions and on transcript levels of biofilm-associated genes vicR and covR, in a dose-dependent manner.
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17
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Alves LA, Ganguly T, Harth-Chú ÉN, Kajfasz J, Lemos JA, Abranches J, Mattos-Graner RO. PepO is a target of the two-component systems VicRK and CovR required for systemic virulence of Streptococcus mutans. Virulence 2020; 11:521-536. [PMID: 32427040 PMCID: PMC7239026 DOI: 10.1080/21505594.2020.1767377] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/10/2020] [Accepted: 03/29/2020] [Indexed: 12/14/2022] Open
Abstract
Streptococcus mutans, a cariogenic species, is often associated with cardiovascular infections. Systemic virulence of specific S. mutans serotypes has been associated with the expression of the collagen- and laminin-binding protein Cnm, which is transcriptionally regulated by VicRK and CovR. In this study, we characterized a VicRK- and CovR-regulated gene, pepO, coding for a conserved endopeptidase. Transcriptional and protein analyses revealed that pepO is highly expressed in S. mutans strains resistant to complement immunity (blood isolates) compared to oral isolates. Gel mobility assay, transcriptional, and Western blot analyses revealed that pepO is repressed by VicR and induced by CovR. Deletion of pepO in the Cnm+ strain OMZ175 (OMZpepO) or in the Cnm- UA159 (UApepO) led to an increased susceptibility to C3b deposition, and to low binding to complement proteins C1q and C4BP. Additionally, pepO mutants showed diminished ex vivo survival in human blood and impaired capacity to kill G. mellonella larvae. Inactivation of cnm in OMZ175 (OMZcnm) resulted in increased resistance to C3b deposition and unaltered blood survival, although both pepO and cnm mutants displayed attenuated virulence in G. mellonella. Unlike OMZcnm, OMZpepO could invade HCAEC endothelial cells. Supporting these phenotypes, recombinant proteins rPepO and rCnmA showed specific profiles of binding to C1q, C4BP, and to other plasma (plasminogen, fibronectin) and extracellular matrix proteins (type I collagen, laminin). Therefore this study identifies a novel VicRK/CovR-target required for immune evasion and host persistence, pepO, expanding the roles of VicRK and CovR in regulating S. mutans virulence.
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Affiliation(s)
- Lívia A. Alves
- Department of Oral Diagnosis, Piracicaba Dental School – State University of Campinas, Piracicaba, SP, Brazil
| | - Tridib Ganguly
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Érika N. Harth-Chú
- Department of Oral Diagnosis, Piracicaba Dental School – State University of Campinas, Piracicaba, SP, Brazil
| | - Jessica Kajfasz
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - José A. Lemos
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Jacqueline Abranches
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Renata O. Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School – State University of Campinas, Piracicaba, SP, Brazil
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Deciphering Streptococcal Biofilms. Microorganisms 2020; 8:microorganisms8111835. [PMID: 33233415 PMCID: PMC7700319 DOI: 10.3390/microorganisms8111835] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/10/2020] [Accepted: 11/17/2020] [Indexed: 12/19/2022] Open
Abstract
Streptococci are a diverse group of bacteria, which are mostly commensals but also cause a considerable proportion of life-threatening infections. They colonize many different host niches such as the oral cavity, the respiratory, gastrointestinal, and urogenital tract. While these host compartments impose different environmental conditions, many streptococci form biofilms on mucosal membranes facilitating their prolonged survival. In response to environmental conditions or stimuli, bacteria experience profound physiologic and metabolic changes during biofilm formation. While investigating bacterial cells under planktonic and biofilm conditions, various genes have been identified that are important for the initial step of biofilm formation. Expression patterns of these genes during the transition from planktonic to biofilm growth suggest a highly regulated and complex process. Biofilms as a bacterial survival strategy allow evasion of host immunity and protection against antibiotic therapy. However, the exact mechanisms by which biofilm-associated bacteria cause disease are poorly understood. Therefore, advanced molecular techniques are employed to identify gene(s) or protein(s) as targets for the development of antibiofilm therapeutic approaches. We review our current understanding of biofilm formation in different streptococci and how biofilm production may alter virulence-associated characteristics of these species. In addition, we have summarized the role of surface proteins especially pili proteins in biofilm formation. This review will provide an overview of strategies which may be exploited for developing novel approaches against biofilm-related streptococcal infections.
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19
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Competence-Stimulating-Peptide-Dependent Localized Cell Death and Extracellular DNA Production in Streptococcus mutans Biofilms. Appl Environ Microbiol 2020; 86:AEM.02080-20. [PMID: 32948520 DOI: 10.1128/aem.02080-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/14/2020] [Indexed: 02/06/2023] Open
Abstract
Extracellular DNA (eDNA) is a biofilm component that contributes to the formation and structural stability of biofilms. Streptococcus mutans, a major cariogenic bacterium, induces eDNA-dependent biofilm formation under specific conditions. Since cell death can result in the release and accumulation of DNA, the dead cells in biofilms are a source of eDNA. However, it remains unknown how eDNA is released from dead cells and is localized within S. mutans biofilms. We focused on cell death induced by the extracellular signaling peptide called competence-stimulating peptide (CSP). We demonstrate that nucleic acid release into the extracellular environment occurs in a subpopulation of dead cells. eDNA production induced by CSP was highly dependent on the lytF gene, which encodes an autolysin. Although lytF expression was induced bimodally by CSP, lytF-expressing cells further divided into surviving cells and eDNA-producing dead cells. Moreover, we found that lytF-expressing cells were abundant near the bottom of the biofilm, even when all cells in the biofilm received the CSP signal. Dead cells and eDNA were also abundantly present near the bottom of the biofilm. The number of lytF-expressing cells in biofilms was significantly higher than that in planktonic cultures, which suggests that adhesion to the substratum surface is important for the induction of lytF expression. The deletion of lytF resulted in reduced adherence to a polystyrene surface. These results suggest that lytF expression and eDNA production induced near the bottom of the biofilm contribute to a firmly attached and structurally stable biofilm.IMPORTANCE Bacterial communities encased by self-produced extracellular polymeric substances (EPSs), known as biofilms, have a wide influence on human health and environmental problems. The importance of biofilm research has increased, as biofilms are the preferred bacterial lifestyle in nature. Furthermore, in recent years it has been noted that the contribution of phenotypic heterogeneity within biofilms requires analysis at the single-cell or subpopulation level to understand bacterial life strategies. In Streptococcus mutans, a cariogenic bacterium, extracellular DNA (eDNA) contributes to biofilm formation. However, it remains unclear how and where the cells produce eDNA within the biofilm. We focused on LytF, an autolysin that is induced by extracellular peptide signals. We used single-cell level imaging techniques to analyze lytF expression in the biofilm population. Here, we show that S. mutans generates eDNA by inducing lytF expression near the bottom of the biofilm, thereby enhancing biofilm adhesion and structural stability.
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Bikash CR, Tal-Gan Y. Structure Activity Relationship Study of the XIP Quorum Sensing Pheromone in Streptococcus mutans Reveal Inhibitors of the Competence Regulon. ACS Chem Biol 2020; 15:2833-2841. [PMID: 32946208 DOI: 10.1021/acschembio.0c00650] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The dental cariogenic pathogen Streptococcus mutans coordinates competence for genetic transformation via two peptide pheromones, competence stimulating peptide (CSP) and comX-inducing peptide (XIP). CSP is sensed by the comCDE system and induces competence indirectly, whereas XIP is sensed by the comRS system and induces competence directly. In chemically defined media (CDM), after uptake by oligopeptide permease, XIP interacts with the cytosolic receptor ComR to form the XIP::ComR complex that activates the expression of comX, an alternative sigma factor that initiates the transcription of late-competence genes. In this study, we set out to determine the molecular mechanism of XIP::ComR interaction. To this end, we performed systematic replacement of the amino acid residues in the XIP pheromone and assessed the ability of the mutated analogs to modulate the competence regulon in CDM. We were able to identify structural features that are important to ComR binding and activation. Our structure-activity relationship insights led us to construct multiple XIP-based inhibitors of the comRS pathway. Furthermore, when comCDE and comRS were both stimulated with CSP and XIP, respectively, a lead XIP-based inhibitor was able to maintain the inhibitory activity. Last, phenotypic assays were used to highlight the potential of XIP-based inhibitors to attenuate pathogenicity in S. mutans and to validate the specificity of these compounds to the comRS pathway within the competence regulon. The XIP-based inhibitors developed in this study can be used as lead scaffolds for the design and development of potential therapeutics against S. mutans infections.
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Affiliation(s)
- Chowdhury Raihan Bikash
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada 89557, United States
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada 89557, United States
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21
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Balasubramanian AR, Vasudevan S, Shanmugam K, Lévesque CM, Solomon AP, Neelakantan P. Combinatorial effects of trans-cinnamaldehyde with fluoride and chlorhexidine on Streptococcus mutans. J Appl Microbiol 2020; 130:382-393. [PMID: 32707601 DOI: 10.1111/jam.14794] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/06/2020] [Accepted: 07/18/2020] [Indexed: 01/03/2023]
Abstract
AIMS The aim of this study was to investigate the effects of trans-cinnamaldehyde (TC) and its synergistic activity with chlorhexidine (CHX) and fluoride against Streptococcus mutans. METHODS AND RESULTS Streptococcus mutans UA159 was treated with TC alone and in combination with CHX or sodium fluoride. The synergy profile was analysed using the Zero Interaction Potency model. TC showed strong synergism (synergy score of 21·697) with CHX, but additive effect (synergy score of 5·298) with fluoride. TC and the combinations were tested for acid production (glycolytic pH drop) and biofilm formation by S. mutans, and nitric oxide production in macrophages. TC significantly inhibited sucrose-dependent biofilm formation and acid production by S. mutans. Mechanistic studies were carried out by qRT-PCR-based transcriptomic studies which showed that TC acts by impairing genes related to metabolism, quorum sensing, bacteriocin expression, stress tolerance and biofilm formation. CONCLUSIONS trans-Cinnamaldehyde potentiates CHX and sodium fluoride in inhibiting S. mutans biofilms and virulence through multiple mechanisms. This study sheds significant new light on the potential to develop TC as an anti-caries treatment. SIGNIFICANCE AND IMPACT OF THE STUDY Oral diseases were classified as a 'silent epidemic' in the US Surgeon General's Report on Oral Health. Two decades later, >4 billion people are still affected worldwide by caries, having significant effects on the quality of life. There is an urgent need to develop novel compounds and strategies to combat dental caries. Here, we prove that TC downregulates multiple pathways and potentiates the CHX and fluoride to prevent S. mutans biofilms and virulence. This study sheds significant new light on the potential to develop TC in combination with CHX or fluoride as novel treatments to arrest dental caries.
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Affiliation(s)
- A R Balasubramanian
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
| | - S Vasudevan
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
| | - K Shanmugam
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
| | - C M Lévesque
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - A P Solomon
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
| | - P Neelakantan
- Faculty of Dentistry, The University of Hong Kong, Hong Kong, Hong Kong SAR
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Multi-targeted Antisense Oligonucleotide Delivery by a Framework Nucleic Acid for Inhibiting Biofilm Formation and Virulence. NANO-MICRO LETTERS 2020; 12:74. [PMID: 34138282 PMCID: PMC7770702 DOI: 10.1007/s40820-020-0409-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 02/12/2020] [Indexed: 02/05/2023]
Abstract
A framework nucleic acid delivery system was developed through self-assembly, which can deliver antisense oligonucleotides against multiple targets in bacterial cells. The ASOs-tFNAs (750 nM) was found to simultaneously inhibit the expression of gtfBCD, gbpB, and ftf, and significantly reduce the extracellular polysaccharide synthesis and biofilm thickness.
Biofilm formation is responsible for numerous chronic infections and represents a serious health challenge. Bacteria and the extracellular polysaccharides (EPS) cause biofilms to become adherent, toxic, resistant to antibiotics, and ultimately difficult to remove. Inhibition of EPS synthesis can prevent the formation of bacterial biofilms, reduce their robustness, and promote removal. Here, we have developed a framework nucleic acid delivery system with a tetrahedral configuration. It can easily access bacterial cells and functions by delivering antisense oligonucleotides that target specific genes. We designed antisense oligonucleotide sequences with multiple targets based on conserved regions of the VicK protein-binding site. Once delivered to bacterial cells, they significantly decreased EPS synthesis and biofilm thickness. Compared to existing approaches, this system is highly efficacious because it simultaneously reduces the expression of all targeted genes (gtfBCD, gbpB, ftf). We demonstrate a novel nucleic acid-based nanomaterial with multi-targeted inhibition that has great potential for the treatment of chronic infections caused by biofilms.![]()
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Ishkov IP, Ahn SJ, Rice KC, Hagen SJ. Environmental Triggers of lrgA Expression in Streptococcus mutans. Front Microbiol 2020; 11:18. [PMID: 32047487 PMCID: PMC6997555 DOI: 10.3389/fmicb.2020.00018] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/07/2020] [Indexed: 11/13/2022] Open
Abstract
The cidAB and lrgAB operons of Streptococcus mutans encode proteins that are structurally similar to the bacteriophage lambda family of holin-antiholin proteins, which are believed to facilitate cell death in other bacterial species. Although their precise function is not known, cidAB and lrgAB are linked to multiple virulence traits of S. mutans, including oxidative stress tolerance, biofilm formation, and autolysis. Here we investigate the regulation of lrgAB which in S. mutans shows a complex dependence on growth conditions that is not fully understood. By combining single-cell imaging of a fluorescent gene reporter with microfluidic control of the extracellular environment, we identify specific environmental cues that trigger lrgA expression and characterize cell-to-cell heterogeneity in lrgA activity. We find that the very abrupt activation of lrgA at stationary phase is tightly synchronized across the population. This activation is controlled by a small number of inputs that are sensitive to growth phase: extracellular pyruvate, glucose, and molecular oxygen. Activation of lrgA appears to be self-limiting, so that strong expression of lrgA is confined to a short interval of time. lrgA is programmed to switch on briefly at the end of exponential growth, as glucose and molecular oxygen are exhausted and extracellular pyruvate is available. Our findings are consistent with studies of other bacteria showing that homologs of lrgAB participate, with input from lytST, in the reimport of pyruvate for anaerobic fermentative growth.
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Affiliation(s)
- Ivan P Ishkov
- Department of Physics, University of Florida, Gainesville, FL, United States
| | - Sang-Joon Ahn
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, United States
| | - Kelly C Rice
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, United States
| | - Stephen J Hagen
- Department of Physics, University of Florida, Gainesville, FL, United States
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Lei L, Zhang B, Mao M, Chen H, Wu S, Deng Y, Yang Y, Zhou H, Hu T. Carbohydrate Metabolism Regulated by Antisense vicR RNA in Cariogenicity. J Dent Res 2019; 99:204-213. [PMID: 31821772 DOI: 10.1177/0022034519890570] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Streptococcus mutans is a major cariogenic pathogen that resides in multispecies oral microbial biofilms. The VicRK 2-component system is crucial for bacterial adaptation, virulence, and biofilm organization and contains a global and vital response regulator, VicR. Notably, we identified an antisense vicR RNA (AS vicR) associated with an adjacent RNase III–encoding ( rnc) gene that was relevant to microRNA-size small RNAs (msRNAs). Here, we report that ASvicR overexpression significantly impeded bacterial growth, biofilm exopolysaccharide synthesis, and cariogenicity in vivo. Transcriptome analysis revealed that the AS vicR RNA mainly regulated carbohydrate metabolism. In particular, overproducing AS vicR demonstrated a reduction in galactose and glucose metabolism by monosaccharide composition analysis. The results of high-performance gel permeation chromatography revealed that the water-insoluble glucans isolated from AS vicR presented much lower molecular weights. Furthermore, direct evidence showed that total RNAs were disrupted by rnc-encoded RNase III. With the coexpression of T4 RNA ligase, putative msRNA1657, which is an rnc-related messenger RNA, was verified to bind to the 5′-UTR regions of the vicR gene. Furthermore, AS vicR regulation revealed a sponge regulatory-mediated network for msRNA associated with adjacent RNase III–encoding genes. There was an increase in AS vicR transcript levels in clinical S. mutans strains from caries-free children, while the expression of AS vicR was decreased in early childhood caries patients; this outcome may be explored as a potential strategy contributing to the management of dental caries. Taken together, our findings suggest an important role of AS vicR-mediated sponge regulation in S. mutans, indicating the characterization of lactose metabolism by a vital response regulator in cariogenicity. These findings have a number of implications and have reshaped our understanding of bacterial gene regulation from its transcriptional conception to the key roles of regulatory RNAs.
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Affiliation(s)
- L. Lei
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - B. Zhang
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - M. Mao
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Endodontics, College of Stomatology, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - H. Chen
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - S. Wu
- West China School of Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Y. Deng
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Y. Yang
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - H. Zhou
- Department of Oral Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - T. Hu
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
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Cao Y, Yin H, Wang W, Pei P, Wang Y, Wang X, Jiang J, Luo SZ, Chen L. Killing Streptococcus mutans in mature biofilm with a combination of antimicrobial and antibiofilm peptides. Amino Acids 2019; 52:1-14. [PMID: 31797056 DOI: 10.1007/s00726-019-02804-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 11/11/2019] [Indexed: 10/25/2022]
Abstract
Biofilm poses a serious challenge for the treatment of bacterial infections, as it endows bacteria a pronounced resistance to traditional antibiotics. Antimicrobial peptides (AMPs) are considered potential substitutes for antibiotics. Combinational use of AMPs with other compounds to exert antibiofilm effects has been proved to be an effective means to reduce their toxicity and maximize their antimicrobial activity. However, the combination of various AMPs with different action mechanisms is rarely investigated. A newly designed lytic AMP ZXR-2.3 combined with antibiofilm peptide IDR-1018 or KT2 was tested for the antibiofilm effect on mature Streptococcus mutans biofilms. In general, the combination of ZXR-2.3 + IDR-1018 displayed synergistic effect on both biofilm eradication and bacterial killing, while ZXR-2.3 + KT2 showed no obvious synergism. The confocal images of preformed S. mutans biofilms confirmed the effective bactericidal activity of ZXR-2.3 + IDR-1018. A tube system was applied to investigate the biofilm infection under a flow of medium and SEM images indicated the biofilm disruption and bacterial killing effects of ZXR-2.3 + IDR-1018. Quantitative RT-PCR analysis showed that IDR-1018 induced dramatic changes in the mRNA expressions of the quorum sensing (QS) related genes comC, comD, vicR, and vicK of S. mutans in mature biofilms, whereas the other peptides and ciprofloxacin did not cause obvious changes in these genes. This might explain the better synergism of ZXR-2.3 and IDR-1018. The results of this study provide a potential application using the combination of different AMPs in the treatment of mature biofilm infection.
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Affiliation(s)
- Yimeng Cao
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China
| | - Huiwei Yin
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China
| | - Wujun Wang
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China
| | - Pengfei Pei
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China
| | - Yin Wang
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China
| | - Xinyu Wang
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China
| | - Jianhui Jiang
- Engineering Laboratory of Chemical Resources Utilization in South Xinjiang of Xinjiang Production and Construction Corps, College of Life Sciences, Tarim University, Alar, Xinjiang, 843300, China
| | - Shi-Zhong Luo
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China.
| | - Long Chen
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China.
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Quantitative Proteomics Uncovers the Interaction between a Virulence Factor and Mutanobactin Synthetases in Streptococcus mutans. mSphere 2019; 4:4/5/e00429-19. [PMID: 31554721 PMCID: PMC6763767 DOI: 10.1128/msphere.00429-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Streptococcus mutans is the major bacterium associated with dental caries. In order to thrive on the highly populated tooth surface and cause disease, S. mutans must be able to protect itself from hydrogen peroxide-producing commensal bacteria and compete effectively against the neighboring microbes. S. mutans produces mutacins, small antimicrobial peptides which help control the population of competing bacterial species. In addition, S. mutans produces a peptide called mutanobactin, which offers S. mutans protection against oxidative stress. Here, we uncover a new link between the putative glycosyltransferase SMU_833 and the mutanobactin-synthesizing protein complex through quantitative proteomic analysis and a tandem-affinity protein purification scheme. Furthermore, we show that SMU_833 mediates bacterial sensitivity to oxidative stress and bacterial ability to compete with commensal streptococci. This study has revealed a previously unknown association between SMU_833 and mutanobactin and demonstrated the importance of SMU_833 in the fitness of S. mutans. Streptococcus mutans, the primary etiological agent of tooth decay, has developed multiple adhesion and virulence factors which enable it to colonize and compete with other bacteria. The putative glycosyltransferase SMU_833 is important for the virulence of S. mutans by altering the biofilm matrix composition and cariogenicity. In this study, we further characterized the smu_833 mutant by evaluating its effects on bacterial fitness. Loss of SMU_833 led to extracellular DNA-dependent bacterial aggregation. In addition, the mutant was more susceptible to oxidative stress and less competitive against H2O2 producing oral streptococci. Quantitative proteomics analysis revealed that SMU_833 deficiency resulted in the significant downregulation of 10 proteins encoded by a biosynthetic gene cluster responsible for the production of mutanobactin, a compound produced by S. mutans which helps it survive oxidative stress. Tandem affinity purification demonstrated that SMU_833 interacts with the synthetic enzymes responsible for the production of mutanobactin. Similar to the smu_833 mutant, the deletion of the mutanobactin gene cluster rendered the mutant less competitive against H2O2-producing streptococci. Our studies revealed a new link between SMU_833 virulence and mutanobactin, suggesting that SMU_833 represents a new virulent target that can be used to develop potential anticaries therapeutics. IMPORTANCEStreptococcus mutans is the major bacterium associated with dental caries. In order to thrive on the highly populated tooth surface and cause disease, S. mutans must be able to protect itself from hydrogen peroxide-producing commensal bacteria and compete effectively against the neighboring microbes. S. mutans produces mutacins, small antimicrobial peptides which help control the population of competing bacterial species. In addition, S. mutans produces a peptide called mutanobactin, which offers S. mutans protection against oxidative stress. Here, we uncover a new link between the putative glycosyltransferase SMU_833 and the mutanobactin-synthesizing protein complex through quantitative proteomic analysis and a tandem-affinity protein purification scheme. Furthermore, we show that SMU_833 mediates bacterial sensitivity to oxidative stress and bacterial ability to compete with commensal streptococci. This study has revealed a previously unknown association between SMU_833 and mutanobactin and demonstrated the importance of SMU_833 in the fitness of S. mutans.
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Emergent Properties in Streptococcus mutans Biofilms Are Controlled through Adhesion Force Sensing by Initial Colonizers. mBio 2019; 10:mBio.01908-19. [PMID: 31506311 PMCID: PMC6737243 DOI: 10.1128/mbio.01908-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bacterial adhesion is accompanied by altered gene expression, leading to "emergent" properties of biofilm bacteria that are alien to planktonic ones. With the aim of revealing the role of environmental adhesion forces in emergent biofilm properties, genes in Streptococcus mutans UA159 and a quorum-sensing-deficient mutant were identified that become expressed after adhesion to substratum surfaces. Using atomic force microscopy, adhesion forces of initial S. mutans colonizers on four different substrata were determined and related to gene expression. Adhesion forces upon initial contact were similarly low across different substrata, ranging between 0.2 and 1.2 nN regardless of the strain considered. Bond maturation required up to 21 s, depending on the strain and substratum surface involved, but stationary adhesion forces also were similar in the parent and in the mutant strain. However, stationary adhesion forces were largest on hydrophobic silicone rubber (19 to 20 nN), while being smallest on hydrophilic glass (3 to 4 nN). brpA gene expression in thin (34 to 48 μm) 5-h S. mutans UA159 biofilms was most sensitive to adhesion forces, while expression of gbpB and comDE expressions was weakly sensitive. ftf, gtfB, vicR, and relA expression was insensitive to adhesion forces. In thicker (98 to 151 μm) 24-h biofilms, adhesion-force-induced gene expression and emergent extracellular polymeric substance (EPS) production were limited to the first 20 to 30 μm above a substratum surface. In the quorum-sensing-deficient S. mutans, adhesion-force-controlled gene expression was absent in both 5- and 24-h biofilms. Thus, initial colonizers of substratum surfaces sense adhesion forces that externally trigger emergent biofilm properties over a limited distance above a substratum surface through quorum sensing.IMPORTANCE A new concept in biofilm science is introduced: "adhesion force sensitivity of genes," defining the degree up to which expression of different genes in adhering bacteria is controlled by the environmental adhesion forces they experience. Analysis of gene expression as a function of height in a biofilm showed that the information about the substratum surface to which initially adhering bacteria adhere is passed up to a biofilm height of 20 to 30 μm above a substratum surface, highlighting the importance and limitations of cell-to-cell communication in a biofilm. Bacteria in a biofilm mode of growth, as opposed to planktonic growth, are responsible for the great majority of human infections, predicted to become the number one cause of death in 2050. The concept of adhesion force sensitivity of genes provides better understanding of bacterial adaptation in biofilms, direly needed for the design of improved therapeutic measures that evade the recalcitrance of biofilm bacteria to antimicrobials.
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Underhill SAM, Shields RC, Burne RA, Hagen SJ. Carbohydrate and PepO control bimodality in competence development by Streptococcus mutans. Mol Microbiol 2019; 112:1388-1402. [PMID: 31403729 DOI: 10.1111/mmi.14367] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2019] [Indexed: 01/17/2023]
Abstract
In Streptococcus mutans, the alternative sigma factor ComX controls entry into genetic competence. Competence stimulating peptide (CSP) induces bimodal expression of comX, with only a fraction of the population becoming transformable. Curiously, the bimodality of comX is affected by peptides in the growth medium and by carbohydrate source. CSP elicits bimodal expression of comX in media rich in small peptides, but CSP elicits no response in defined media lacking small peptides. In addition, growth on certain sugars increases the proportion of the population that activates comX in response to CSP. By investigating the connection between media and comX bimodality, we find evidence for two mechanisms that modulate transcriptional positive feedback in the ComRS system, where comX bimodality originates. We find that the endopeptidase PepO suppresses the ComRS feedback loop, most likely by degrading the XIP/ComS feedback signal. Deletion of pepO eliminates comX bimodality, leading to a unimodal comX response to CSP in both defined and complex media. We also find that CSP stimulates the ComRS feedback system by upregulating comR in a carbohydrate source-dependent fashion. Our data provide mechanistic insight into how S. mutans regulates bimodality and explain the puzzle of growth medium effects on competence induction by CSP.
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Affiliation(s)
- Simon A M Underhill
- Department of Physics, University of Florida, 2001 Museum Road, Gainesville, FL, 32611, USA
| | - Robert C Shields
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL, 32610, USA
| | - Robert A Burne
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL, 32610, USA
| | - Stephen J Hagen
- Department of Physics, University of Florida, 2001 Museum Road, Gainesville, FL, 32611, USA
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Liu S, Li H, Guo Z, Guan J, Sun Y, Zhang K. Insight into the Effect of Small RNA srn225147 on Mutacin IV in Streptococcus mutans. Indian J Microbiol 2019; 59:445-450. [PMID: 31762507 DOI: 10.1007/s12088-019-00820-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 08/22/2019] [Indexed: 12/11/2022] Open
Abstract
Streptococcus mutans (S. mutans) is a serious microbe causing dental caries. Mutacin IV is an effective bacteriocin produced by S. mutans to antagonize numerous non-mutans streptococcal species. However, the posttranscriptional regulation of mutacin IV remains unclear. This study aimed to analyze the effect of small RNA srn225147 on mutacin IV. The functional prediction suggested that srn225147 is involved in the production of mutacin IV, an important secondary metabolite. According to RNAhybrid and RNAPredator prediction, the mutacin IV formation-associated gene comD is a target of srn225147. We further analyzed the roles of srn225147 and comD in 20 S. mutans clinical strains with high production of mutacin IV (High-IV group) and lacking mutacin IV (None-IV group). Levels of comD expression were significantly higher in the High-IV group, whereas the Non-IV group showed relatively higher expression of srn225147, with a negative correlation observed between srn225147 and comD. Moreover, compared to the mimic negative control (NC) group, comD expression was decreased at 400-fold srn225147 overexpression but increased at approximately 1400-fold overexpression. Although the production of mutacin IV in the 1400-fold change srn225147 mimic group was larger than that in the 400-fold change mimic group, there was no significant difference in the production of mutacin IV between the srn225147 mimic group and mimic NC group. These results indicate that srn225147 has a two-way regulation effect on the expression of comD but that its regulation in the production of mutacin IV is weak.
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Affiliation(s)
- Shanshan Liu
- 1Department of Stomatology, The First Affiliated Hospital of Bengbu Medical College, 287 Chang Huai Road, Bengbu, 233004 China
| | - Huihui Li
- 2Department of Microbiology and Anhui Key Laboratory of Infection and Immunity, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030 China
| | - Zhenfei Guo
- 1Department of Stomatology, The First Affiliated Hospital of Bengbu Medical College, 287 Chang Huai Road, Bengbu, 233004 China
| | - Junchang Guan
- 2Department of Microbiology and Anhui Key Laboratory of Infection and Immunity, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030 China
| | - Yu Sun
- 3Department of Biochemistry and Molecular Biology, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030 China
| | - Kai Zhang
- 1Department of Stomatology, The First Affiliated Hospital of Bengbu Medical College, 287 Chang Huai Road, Bengbu, 233004 China
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Wu X, Song Q, Han A. Interacting proteins of the essential two-component system YycFG in Bacillus subtilis. J Basic Microbiol 2019; 59:950-959. [PMID: 31339578 DOI: 10.1002/jobm.201800701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 06/14/2019] [Accepted: 06/24/2019] [Indexed: 11/06/2022]
Abstract
Two-component signal transduction systems (TCSs) play a major role in adaption and survival of microorganisms in a dynamic and sometimes dangerous environment. YycFG is an essential TCS for many Gram-positive bacteria, such as Bacillus subtilis, which regulates many important biological processes. However, its functional essentiality remains largely unknown. Here, we report several YycFG interacting proteins through coimmunoprecipitation (Co-IP) and mass spectrometry (MS) analyses. We engineered the B. subtilis genome by a knock-in approach to express YycG with a C-terminal Flag and YycF with an N-terminal HA tag. Immunoprecipitated fractions using anti-Flag or anti-HA agarose were subjected to MS analyses. A total of 41 YycG interacting proteins and four YycF interacting proteins were identified, most of which are involved in cellular metabolic processes, including cell wall synthesis and modification. The interactions of YycG with AsnB and FabL, as examples, were further validated in vitro. This study provided a clue that YycFG may be directly involved in regulation of bacterial central metabolic pathways.
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Affiliation(s)
- Xuanang Wu
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang'an, Xiamen, China
| | - Qi Song
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang'an, Xiamen, China
| | - Aidong Han
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang'an, Xiamen, China
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CovR and VicRKX Regulate Transcription of the Collagen Binding Protein Cnm of Streptococcus mutans. J Bacteriol 2018; 200:JB.00141-18. [PMID: 30201780 DOI: 10.1128/jb.00141-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 09/04/2018] [Indexed: 11/20/2022] Open
Abstract
Cnm is a surface-associated protein present in a subset of Streptococcus mutans strains that mediates binding to extracellular matrices, intracellular invasion, and virulence. Here, we showed that cnm transcription is controlled by the global regulators CovR and VicRKX. In silico analysis identified multiple putative CovR- and VicR-binding motifs in the regulatory region of cnm as well as in the downstream gene pgfS, which is associated with the posttranslational modification of Cnm. Electrophoretic mobility shift assays revealed that CovR and VicR specifically and independently bind to the cnm and pgfS promoter regions. Quantitative real-time PCR and Western blot analyses of ΔcovR and ΔvicK strains as well as of a strain overexpressing vicRKX revealed that CovR functions as a positive regulator of cnm, whereas VicRKX acts as a negative regulator. In agreement with the role of VicRKX as a repressor, the ΔvicK strain showed enhanced binding to collagen and laminin and higher intracellular invasion rates. Overexpression of vicRKX was associated with decreased rates of intracellular invasion but did not affect collagen or lamin binding activities, suggesting that this system controls additional genes involved in binding to these extracellular matrix proteins. As expected, based on the role of CovR in cnm regulation, the ΔcovR strain showed decreased intracellular invasion rates, but, unexpectedly collagen and laminin binding activities were increased in this mutant strain. Collectively, the results presented here expand the repertoire of virulence-related genes regulated by CovR and VicRKX to include the core gene pgfS and the noncore gene cnm IMPORTANCE Streptococcus mutans is a major pathogen associated with dental caries and also implicated in systemic infections, in particular, infective endocarditis. The Cnm adhesin of S. mutans is an important virulence factor associated with systemic infections and caries severity. Despite its role in virulence, the regulatory mechanisms governing cnm expression are poorly understood. Here, we describe the identification of two independent regulatory systems controlling the transcription of cnm and the downstream pgfS-pgfM1-pgfE-pgfM2 operon. A better understanding of the mechanisms controlling expression of virulence factors like Cnm can facilitate the development of new strategies to treat bacterial infections.
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Abstract
Entry into genetic competence in streptococci is controlled by ComX, an alternative sigma factor for genes that enable the import of exogenous DNA. In Streptococcus mutans, the immediate activator of comX is the ComRS quorum system. ComS is the precursor of XIP, a seven-residue peptide that is imported into the cell and interacts with the cytosolic receptor ComR to form a transcriptional activator for both comX and comS Although intercellular quorum signaling by ComRS has been demonstrated, observations of bimodal expression of comX suggest that comRS may also function as an intracellular feedback loop, activating comX without export or detection of extracellular XIP. Here we used microfluidic and single-cell methods to test whether ComRS induction of comX requires extracellular XIP or ComS. We found that individual comS-overexpressing cells activate their own comX, independently of the rate at which their growth medium is replaced. However, in the absence of lysis they do not activate comS-deficient mutants growing in coculture. We also found that induction of comR and comS genes introduced into Escherichia coli cells leads to activation of a comX reporter. Therefore, ComRS control of comX does not require either the import or extracellular accumulation of ComS or XIP or specific processing of ComS to XIP. We also found that endogenously and exogenously produced ComS and XIP have inequivalent effects on comX activation. These data are fully consistent with identification of intracellular positive feedback in comS transcription as the origin of bimodal comX expression in S. mutans IMPORTANCE The ComRS system can function as a quorum sensing trigger for genetic competence in S. mutans The signal peptide XIP, which is derived from the precursor ComS, enters the cell and interacts with the Rgg-type cytosolic receptor ComR to activate comX, which encodes the alternative sigma factor for the late competence genes. Previous studies have demonstrated intercellular signaling via ComRS, although release of the ComS or XIP peptide to the extracellular medium appears to require lysis of the producing cells. Here we tested the complementary hypothesis that ComRS can drive comX through a purely intracellular mechanism that does not depend on extracellular accumulation or import of ComS or XIP. By combining single-cell, coculture, and microfluidic approaches, we demonstrated that endogenously produced ComS can enable ComRS to activate comX without requiring processing, export, or import. These data provide insight into intracellular mechanisms that generate noise and heterogeneity in S. mutans competence.
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Zheng C, Li L, Ge H, Meng H, Li Y, Bei W, Zhou X. Role of two-component regulatory systems in the virulence of Streptococcus suis. Microbiol Res 2018; 214:123-128. [PMID: 30031474 DOI: 10.1016/j.micres.2018.07.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 06/19/2018] [Accepted: 07/07/2018] [Indexed: 01/01/2023]
Abstract
Streptococcus suis is an important zoonotic pathogen that causes severe infections and great economic losses worldwide. Understanding how this pathogen senses and responds to environmental signals during the infectious process can offer insight into its pathogenesis and may be helpful in the development of drug targets. Two-component regulatory systems (TCSs) play an essential role in this environmental response. In S. suis, at least 15 groups of TCSs have been predicted. Among them, several have been demonstrated to be involved in virulence and/or stress response. In this review, we discuss the progress in the study of TCSs in S. suis, focusing on the role of these systems in the virulence of this bacterium.
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Affiliation(s)
- Chengkun Zheng
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China; State Key Laboratory of Agricultural Microbiology/The Cooperative Innovation Center for Sustainable Pig Production, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
| | - Lingzhi Li
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Haojie Ge
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Hongmei Meng
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Yang Li
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Weicheng Bei
- State Key Laboratory of Agricultural Microbiology/The Cooperative Innovation Center for Sustainable Pig Production, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Xiaohui Zhou
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China; Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT, 06269, USA.
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Srinivasan VB, Angrasan M, Chandel N, Rajamohan G. Genome sequence and comparative analysis of Bacillus cereus BC04, reveals genetic diversity and alterations for antimicrobial resistance. Funct Integr Genomics 2018; 18:477-487. [PMID: 29619642 DOI: 10.1007/s10142-018-0600-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 03/03/2018] [Accepted: 03/05/2018] [Indexed: 11/29/2022]
Abstract
In this study, we delineated the genome sequence of a Bacillus cereus strain BC04 isolated from a stool sample in India. The draft genome is 5.1 Mb in size and consists of total 109 scaffolds, GC content is 35.2% with 5182 coding genes. The comparative analysis with other completely sequenced genomes highlights the unique presence of genomic islands, hemolysin, capsular synthetic protein, modifying enzymes accC7 and catA15, regulators of antibiotic resistance MarR and LysR with annotated functions related to virulence, stress response, and antimicrobial resistance. Overall, this study not only signifies the genetic diversity in gut isolate BC04 in particular, but also pinpoints the presence of unique genes possessed by B. cereus which can be pertinently exploited to design novel drugs and intervention strategies for the treatment of food borne diseases.
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Affiliation(s)
- Vijaya Bharathi Srinivasan
- Bacterial Signaling and Drug Resistance Laboratory, CSIR-Institute of Microbial Technology, Sector 39-A, Chandigarh, 160036, India
| | - Mahavinod Angrasan
- Bacterial Signaling and Drug Resistance Laboratory, CSIR-Institute of Microbial Technology, Sector 39-A, Chandigarh, 160036, India
| | - Neha Chandel
- Bacterial Signaling and Drug Resistance Laboratory, CSIR-Institute of Microbial Technology, Sector 39-A, Chandigarh, 160036, India
| | - Govindan Rajamohan
- Bacterial Signaling and Drug Resistance Laboratory, CSIR-Institute of Microbial Technology, Sector 39-A, Chandigarh, 160036, India.
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Zhuang PL, Yu LX, Liao JK, Zhou Y, Lin HC. Relationship between the genetic polymorphisms of vicR and vicK Streptococcus mutans genes and early childhood caries in two-year-old children. BMC Oral Health 2018. [PMID: 29530000 PMCID: PMC5848541 DOI: 10.1186/s12903-018-0501-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background The VicRK two-component signalling system regulates virulence and cariogenicity in Streptococcus mutans (S. mutans). The purpose of this study was to explore the genetic polymorphisms of the vicR and vicK genes, which are associated with dental caries in children with S. mutans. Methods In this study, 121 (from each group) clinical S. mutans strains were isolated from caries-free children and children with high-severity caries to sequence the vicR and vicK genes. Genomic DNA was extracted from S. mutans strains and amplified using PCR. The PCR products were purified and sequenced. A chi-squared test and ABI Variant Reporter software were used to analyse the sequencing results. Results The 242 clinically isolated S. mutans strains contained the full-length vicR and vicK genes. No nucleotide sequence insertions or deletions were observed in the two genes. Four silent point mutations were identified in the vicR genes, and no missense mutations could be detected. Forty-one mutations were identified in the vicK genes. In addition to 32 silent mutations, 9 missense mutations at the 173, 337, 470, 1051, 1132, 1258, 1260, 1277, and 1348 bp positions were found. The distribution frequencies of the missense mutations were not significantly different between the groups, except for the C470T mutation. The frequency of the C470T missense mutation was higher in the high-severity caries group than in the caries-free group. Conclusions vicR sequences are highly conserved in S. mutans clinical isolates. The locus 470 missense mutation of the vicK gene may be related to caries in children with S. mutans.
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Affiliation(s)
- Pei Lin Zhuang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Department of Stomatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yanjian Road West, Guangzhou, 510120, China.,Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, 74 2nd Zhongshan Road, Guangzhou, 510055, China
| | - Li Xia Yu
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, 74 2nd Zhongshan Road, Guangzhou, 510055, China.,Department of Preventive Dentistry, Guanghua School of Stomatology, Sun Yat-Sen University, 56 Lingyuan Road West, Guangzhou, 510055, China
| | - Juan Kun Liao
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Department of Stomatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yanjian Road West, Guangzhou, 510120, China
| | - Yan Zhou
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, 74 2nd Zhongshan Road, Guangzhou, 510055, China.,Department of Preventive Dentistry, Guanghua School of Stomatology, Sun Yat-Sen University, 56 Lingyuan Road West, Guangzhou, 510055, China
| | - Huan Cai Lin
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, 74 2nd Zhongshan Road, Guangzhou, 510055, China. .,Department of Preventive Dentistry, Guanghua School of Stomatology, Sun Yat-Sen University, 56 Lingyuan Road West, Guangzhou, 510055, China.
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36
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Lin TH, Lin CH, Pan TM. The implication of probiotics in the prevention of dental caries. Appl Microbiol Biotechnol 2017; 102:577-586. [PMID: 29192351 DOI: 10.1007/s00253-017-8664-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 11/17/2017] [Accepted: 11/17/2017] [Indexed: 11/30/2022]
Abstract
The current oral health crisis, whose causes are varied and complex, necessitates timely oral evaluation and early detection and treatment of oral health problems. Dramatic changes in eating habits and lifestyles are associated with the recent decline in oral health. Probiotics are "good" bacteria that support digestion and a healthy immune system and offer various health benefits to the host. Traditionally, probiotics have been used to improve gut health; the most common uses have historically been as a treatment or prevention of gastrointestinal infections and disease. During the last decade, studies have additionally suggested the intake of probiotics for oral health purposes. Probiotic use provides an effective strategy to combat oral disease, including the development of dental caries and periodontal infection. The aim of this review is to describe the beneficial roles of probiotic bacteria in the oral cavity and the potential mechanisms by which these bacteria exert their effects on oral health.
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Affiliation(s)
- Tzu-Hsing Lin
- Department of Life Science, College of Life Science and Engineering, National Taitung University, No. 369, Sec. 2, University Road, Taitung City, Taitung County, 95092, Taiwan
| | - Chih-Hui Lin
- Department of Life Science, College of Life Science and Engineering, National Taitung University, No. 369, Sec. 2, University Road, Taitung City, Taitung County, 95092, Taiwan.
| | - Tzu-Ming Pan
- Department of Life Science, College of Life Science and Engineering, National Taitung University, No. 369, Sec. 2, University Road, Taitung City, Taitung County, 95092, Taiwan.,Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan
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37
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Mattos-Graner RO, Duncan MJ. Two-component signal transduction systems in oral bacteria. J Oral Microbiol 2017; 9:1400858. [PMID: 29209465 PMCID: PMC5706477 DOI: 10.1080/20002297.2017.1400858] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 11/01/2017] [Indexed: 01/03/2023] Open
Abstract
We present an overview of how members of the oral microbiota respond to their environment by regulating gene expression through two-component signal transduction systems (TCSs) to support conditions compatible with homeostasis in oral biofilms or drive the equilibrium toward dysbiosis in response to environmental changes. Using studies on the sub-gingival Gram-negative anaerobe Porphyromonas gingivalis and Gram-positive streptococci as examples, we focus on the molecular mechanisms involved in activation of TCS and species specificities of TCS regulons.
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Affiliation(s)
- Renata O. Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas – UNICAMP, São Paulo, Brazil
| | - Margaret J. Duncan
- Department of Oral Medicine, Infection and Immunity, The Forsyth Institute, Cambridge, MA, USA
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38
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Remodeling of the Streptococcus mutans proteome in response to LrgAB and external stresses. Sci Rep 2017; 7:14063. [PMID: 29070798 PMCID: PMC5656683 DOI: 10.1038/s41598-017-14324-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/09/2017] [Indexed: 11/24/2022] Open
Abstract
The Streptococcus mutans Cid/Lrg system represents an ideal model to study how this organism withstands various stressors encountered in the oral cavity. Mutation of lrgAB renders S. mutans more sensitive to oxidative, heat, and vancomycin stresses. Here, we have performed a comprehensive proteomics experiment using label-free quantitative mass spectrometry to compare the proteome changes of wild type UA159 and lrgAB mutant strains in response to these same stresses. Importantly, many of identified proteins showed either a strikingly large fold-change, or were completely suppressed or newly induced in response to a particular stress condition. Notable stress proteome changes occurred in a variety of functional categories, including amino acid biosynthesis, energy metabolism, protein synthesis, transport/binding, and transcriptional/response regulators. In the non-stressed growth condition, mutation of lrgAB significantly altered the abundance of 76 proteins (a fold change >1.4, or <0.6, p-value <0.05) and several of these matched the stress proteome of the wild type strain. Interestingly, the statistical correlation between the proteome changes and corresponding RNA-seq transcriptomic studies was relatively low (rho(ρ) <0.16), suggesting that adaptation to a new environment may require radical proteome turnover or metabolic remodeling. Collectively, this study reinforces the importance of LrgAB to the S. mutans stress response.
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Effects of Arginine on Streptococcus mutans Growth, Virulence Gene Expression, and Stress Tolerance. Appl Environ Microbiol 2017; 83:AEM.00496-17. [PMID: 28526785 DOI: 10.1128/aem.00496-17] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/11/2017] [Indexed: 11/20/2022] Open
Abstract
Streptococcus mutans is a common constituent of oral biofilms and a primary etiologic agent of human dental caries. The bacteria associated with dental caries have potent abilities to produce organic acids from dietary carbohydrates and to grow and metabolize in acidic conditions. By contrast, many commensal bacteria produce ammonia through the arginine deiminase system (ADS), which moderates the pH of oral biofilms. Arginine metabolism by the ADS is a significant deterrent to the initiation and progression of dental caries. In this study, we observed how exogenously provided l-arginine affects the growth, the virulence properties, and the tolerance of environmental stresses of S. mutans Supplementation with 1.5% arginine (final concentration) had an inhibitory effect on the growth of S. mutans in complex and chemically defined media, particularly when cells were exposed to acid or oxidative stress. The genes encoding virulence factors required for attachment/accumulation (gtfB and spaP), bacteriocins (nlmA, nlmB, nlmD, and cipB), and the sigma factor required for competence development (comX) were downregulated during growth with 1.5% arginine. Deep sequencing of RNA (RNA-Seq) comparing the transcriptomes of S. mutans growing in chemically defined media with and without 1.5% arginine revealed differential expression of genes encoding ATP-binding cassette transporters, metal transporters, and constituents required for survival, metabolism, and biofilm formation. Therefore, the mechanisms of action by which arginine inhibits dental caries include direct adverse effects on multiple virulence-related properties of the most common human dental caries pathogen.IMPORTANCE Metabolism of the amino acid arginine by the arginine deiminase system (ADS) of certain oral bacteria raises the pH of dental plaque and provides a selective advantage to health-associated bacteria, thereby protecting the host from dental caries (cavities). Here, we examine the effects of arginine on the cavity-causing bacterium Streptococcus mutans We find that arginine negatively impacts the growth, the pathogenic potential, and the tolerance of environmental stresses in a way that is likely to compromise the ability of S. mutans to cause disease. Using genetic and genomic techniques, multiple mechanisms by which arginine exerts its influence on virulence-related properties of S. mutans are discovered. This report demonstrates that a primary mechanism of action by which arginine inhibits the initiation and progression of dental caries may be by reducing the pathogenic potential of S. mutans.
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Alves LA, Harth-Chu EN, Palma TH, Stipp RN, Mariano FS, Höfling JF, Abranches J, Mattos-Graner RO. The two-component system VicRK regulates functions associated with Streptococcus mutans resistance to complement immunity. Mol Oral Microbiol 2017; 32:419-431. [PMID: 28382721 DOI: 10.1111/omi.12183] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/07/2017] [Accepted: 03/29/2017] [Indexed: 12/16/2022]
Abstract
Streptococcus mutans, a dental caries pathogen, can promote systemic infections upon reaching the bloodstream. The two-component system (TCS) VicRKSm of S. mutans regulates the synthesis of and interaction with sucrose-derived exopolysaccharides (EPS), processes associated with oral and systemic virulence. In this study, we investigated the mechanisms by which VicRKSm affects S. mutans susceptibility to blood-mediated immunity. Compared with parent strain UA159, the vicKSm isogenic mutant (UAvic) showed reduced susceptibility to deposition of C3b of complement, low binding to serum immunoglobulin G (IgG), and low frequency of C3b/IgG-mediated opsonophagocytosis by polymorphonuclear cells in a sucrose-independent way (P<.05). Reverse transcriptase quantitative polymerase chain reaction analysis comparing gene expression in UA159 and UAvic revealed that genes encoding putative peptidases of the complement (pepO and smu.399) were upregulated in UAvic in the presence of serum, although genes encoding murein hydrolases (SmaA and Smu.2146c) or metabolic/surface proteins involved in bacterial interactions with host components (enolase, GAPDH) were mostly affected in a serum-independent way. Among vicKSm -downstream genes (smaA, smu.2146c, lysM, atlA, pepO, smu.399), only pepO and smu.399 were associated with UAvic phenotypes; deletion of both genes in UA159 significantly enhanced levels of C3b deposition and opsonophagocytosis (P<.05). Moreover, consistent with the fibronectin-binding function of PepO orthologues, UAvic showed increased binding to fibronectin. Reduced susceptibility to opsonophagocytosis was insufficient to enhance ex vivo persistence of UAvic in blood, which was associated with growth defects of this mutant under limited nutrient conditions. Our findings revealed that S. mutans employs mechanisms of complement evasion through peptidases, which are controlled by VicRKSm.
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Affiliation(s)
- Livia A Alves
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Erika N Harth-Chu
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Thais H Palma
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Rafael N Stipp
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Flávia S Mariano
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - José F Höfling
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Jacqueline Abranches
- Department of Oral Biology, College of Dentistry - University of Florida, Gainesville, FL, USA
| | - Renata O Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
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Xu T, Wu Y, Lin Z, Bertram R, Götz F, Zhang Y, Qu D. Identification of Genes Controlled by the Essential YycFG Two-Component System Reveals a Role for Biofilm Modulation in Staphylococcus epidermidis. Front Microbiol 2017; 8:724. [PMID: 28491057 PMCID: PMC5405149 DOI: 10.3389/fmicb.2017.00724] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 04/07/2017] [Indexed: 01/11/2023] Open
Abstract
Biofilms play a crucial role in the pathogenicity of Staphylococcus epidermidis, while little is known about whether the essential YycFG two-component signal transduction system (TCS) is involved in biofilm formation. We used antisense RNA (asRNA) to silence the yycFG TCS in order to study its regulatory functions in S. epidermidis. Strain 1457 expressing asRNAyycF exhibited a significant delay (~4–5 h) in entry to log phase, which was partially complemented by overexpressing ssaA. The expression of asRNAyycF and asRNAyycG resulted in a 68 and 50% decrease in biofilm formation at 6 h, respectively, while they had no significant inhibitory effect on 12 h biofilm formation. The expression of asRNAyycF led to a ~5-fold increase in polysaccharide intercellular adhesion (PIA) production, but it did not affect the expression of accumulation-associated protein (Aap) or the release of extracellular DNA. Consistently, quantitative real-time PCR showed that silencing yycF resulted in an increased transcription of biofilm-related genes, including icaA, arlR, sarA, sarX, and sbp. An in silico search of the YycF regulon for the conserved YycF recognition pattern and a modified motif in S. epidermidis, along with additional gel shift and DNase I footprinting assays, showed that arlR, sarA, sarX, and icaA are directly regulated by YycF. Our data suggests that YycFG modulates S. epidermidis biofilm formation in an ica-dependent manner.
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Affiliation(s)
- Tao Xu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Department of Medical Microbiology and Parasitology, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan UniversityShanghai, China.,Key Laboratory of Medical Molecular Virology, Huashan Hospital, Shanghai Medical College of Fudan UniversityShanghai, China
| | - Yang Wu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Department of Medical Microbiology and Parasitology, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan UniversityShanghai, China
| | - Zhiwei Lin
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Department of Medical Microbiology and Parasitology, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan UniversityShanghai, China
| | - Ralph Bertram
- Klinikum Nürnberg Medical School GmbH, Research Department, Paracelsus Medical UniversityNuremberg, Germany.,Department of Microbial Genetics, Faculty of Science, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of TübingenTübingen, Germany
| | - Friedrich Götz
- Department of Microbial Genetics, Faculty of Science, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of TübingenTübingen, Germany
| | - Ying Zhang
- Key Laboratory of Medical Molecular Virology, Huashan Hospital, Shanghai Medical College of Fudan UniversityShanghai, China.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins UniversityBaltimore, MD, USA
| | - Di Qu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Department of Medical Microbiology and Parasitology, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan UniversityShanghai, China
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Jiao Y, Niu LN, Ma S, Li J, Tay FR, Chen JH. Quaternary ammonium-based biomedical materials: State-of-the-art, toxicological aspects and antimicrobial resistance. Prog Polym Sci 2017; 71:53-90. [PMID: 32287485 PMCID: PMC7111226 DOI: 10.1016/j.progpolymsci.2017.03.001] [Citation(s) in RCA: 306] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 03/07/2017] [Accepted: 03/07/2017] [Indexed: 12/20/2022]
Abstract
Microbial infections affect humans worldwide. Many quaternary ammonium compounds have been synthesized that are not only antibacterial, but also possess antifungal, antiviral and anti-matrix metalloproteinase capabilities. Incorporation of quaternary ammonium moieties into polymers represents one of the most promising strategies for preparation of antimicrobial biomaterials. Various polymerization techniques have been employed to prepare antimicrobial surfaces with quaternary ammonium functionalities; in particular, syntheses involving controlled radical polymerization techniques enable precise control over macromolecular structure, order and functionality. Although recent publications report exciting advances in the biomedical field, some of these technological developments have also been accompanied by potential toxicological and antimicrobial resistance challenges. Recent evidenced-based data on the biomedical applications of antimicrobial quaternary ammonium-containing biomaterials that are based on randomized human clinical trials, the golden standard in contemporary medicinal science, are included in the present review. This should help increase visibility, stimulate debates and spur conversations within a wider scientific community on the implications and plausibility for future developments of quaternary ammonium-based antimicrobial biomaterials.
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Affiliation(s)
- Yang Jiao
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, 710032, Xi’an, Shaanxi, China
- Department of Stomatology, PLA Army General Hospital, 100700, Beijing, China
| | - Li-na Niu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, 710032, Xi’an, Shaanxi, China
| | - Sai Ma
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, 710032, Xi’an, Shaanxi, China
| | - Jing Li
- Department of Orthopaedic Oncology, Xijing Hospital Affiliated to the Fourth Military Medical University, 710032, Xi’an, Shaanxi, China
| | - Franklin R. Tay
- Department of Endodontics, The Dental College of Georgia, Augusta University, Augusta, GA, 30912, USA
- Corresponding authors.
| | - Ji-hua Chen
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, 710032, Xi’an, Shaanxi, China
- Corresponding authors.
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Rice KC, Turner ME, Carney OV, Gu T, Ahn SJ. Modification of the Streptococcus mutans transcriptome by LrgAB and environmental stressors. Microb Genom 2017; 3:e000104. [PMID: 28348880 PMCID: PMC5361627 DOI: 10.1099/mgen.0.000104] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/20/2016] [Indexed: 12/14/2022] Open
Abstract
The Streptococcus mutans Cid/Lrg system is central to the physiology of this cariogenic organism, affecting oxidative stress resistance, biofilm formation and competence. Previous transcriptome analyses of lytS (responsible for the regulation of lrgAB expression) and cidB mutants have revealed pleiotropic effects on carbohydrate metabolism and stress resistance genes. In this study, it was found that an lrgAB 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, lrgA and lrgB 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 lrgAB 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 S. mutans UA159 and lrgAB mutant occurred during aerobic and high-temperature growth. Similar to previous studies of a cidB mutant, lrgAB 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 lrgAB was upregulated in the wild-type strain under all three stress conditions. Collectively, these results demonstrate that mutation of lrgAB 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.
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Affiliation(s)
- Kelly C Rice
- 1Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, USA
| | - Matthew E Turner
- 1Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, USA
| | - O'neshia V Carney
- 1Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, USA.,†Present address: Department of Health Outcomes and Policy, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Tongjun Gu
- 2Bioinformatics, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL 32610, USA
| | - Sang-Joon Ahn
- 3Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA
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Kawada-Matsuo M, Komatsuzawa H. Role of Streptococcus mutans two-component systems in antimicrobial peptide resistance in the oral cavity. JAPANESE DENTAL SCIENCE REVIEW 2017; 53:86-94. [PMID: 28725299 PMCID: PMC5501732 DOI: 10.1016/j.jdsr.2016.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 10/14/2016] [Accepted: 12/08/2016] [Indexed: 01/24/2023] Open
Abstract
Approximately 100 trillion microorganisms exist in the oral cavity. For the commensal bacteria of the oral cavity, it is important to adapt to environmental stimuli, including human- or bacteria-derived antimicrobial agents. Recently, bacterial-specific signal transduction regulatory systems, called two-component systems (TCSs), which appear to be focused on sensing and adapting to the environment, were discovered. Streptococcus mutans is an oral commensal bacteria and is also known as a cariogenic bacteria. Although the virulence factors of S. mutans have been well demonstrated, the mechanism underlying the adaptation of the species to the oral cavity is poorly understood. S. mutans UA159 has 15 sets of TCSs. Among them, several have been demonstrated to be involved in acid tolerance, competence and biofilm formation. Recently, together with our findings, it was demonstrated that 5 TCSs were involved in resistance to antimicrobial agents. Furthermore, another TCS was associated with the production of bacteriocin. Six of 15 TCSs are associated with antimicrobial agents, implying that S. mutans can survive in the oral cavity by resisting various antimicrobial peptides. In this review, we highlight the role of antimicrobial peptides in the oral cavity.
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Affiliation(s)
- Miki Kawada-Matsuo
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
| | - Hitoshi Komatsuzawa
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
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Transcriptional Profiling of the Oral Pathogen Streptococcus mutans in Response to Competence Signaling Peptide XIP. mSystems 2017; 2:mSystems00102-16. [PMID: 28066817 PMCID: PMC5209530 DOI: 10.1128/msystems.00102-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/28/2016] [Indexed: 11/20/2022] Open
Abstract
In the cariogenic Streptococcus mutans, competence development is regulated by the ComRS signaling system comprised of the ComR regulator and the ComS prepeptide to the competence signaling peptide XIP (ComX-inducing peptide). Aside from competence development, XIP signaling has been demonstrated to regulate cell lysis, and recently, the expression of bacteriocins, small antimicrobial peptides used by bacteria to inhibit closely related species. Our study further explores the effect of XIP signaling on the S. mutans transcriptome. RNA sequencing revealed that XIP induction resulted in a global change in gene expression that was consistent with a stress response. An increase in several membrane-bound regulators, including HdrRM and BrsRM, involved in bacteriocin production, and the VicRKX system, involved in acid tolerance and biofilm formation, was observed. Furthermore, global changes in gene expression corresponded to changes observed during the stringent response to amino acid starvation. Effects were also observed on genes involved in sugar transport and carbon catabolite repression and included the levQRST and levDEFG operons. Finally, our work identified a novel heat shock-responsive intergenic region, encoding a small RNA, with a potential role in competence shutoff. IMPORTANCE Genetic competence provides bacteria with an opportunity to increase genetic diversity or acquire novel traits conferring a survival advantage. In the cariogenic pathogen Streptococcus mutans, DNA transformation is regulated by the competence stimulating peptide XIP (ComX-inducing peptide). The present study utilizes high-throughput RNA sequencing (RNAseq) to provide a greater understanding of how global gene expression patterns change in response to XIP. Overall, our work demonstrates that in S. mutans, XIP signaling induces a response that resembles the stringent response to amino acid starvation. We further identify a novel heat shock-responsive intergenic region with a potential role in competence shutoff. Together, our results provide further evidence that multiple stress response mechanisms are linked through the genetic competence signaling pathway in S. mutans.
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Sadeghinejad L, Cvitkovitch DG, Siqueira WL, Santerre JP, Finer Y. Triethylene Glycol Up-Regulates Virulence-Associated Genes and Proteins in Streptococcus mutans. PLoS One 2016; 11:e0165760. [PMID: 27820867 PMCID: PMC5098727 DOI: 10.1371/journal.pone.0165760] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/17/2016] [Indexed: 01/30/2023] Open
Abstract
Triethylene glycol dimethacrylate (TEGDMA) is a diluent monomer used pervasively in dental composite resins. Through hydrolytic degradation of the composites in the oral cavity it yields a hydrophilic biodegradation product, triethylene glycol (TEG), which has been shown to promote the growth of Streptococcus mutans, a dominant cariogenic bacterium. Previously it was shown that TEG up-regulated gtfB, an important gene contributing to polysaccharide synthesis function in biofilms. However, molecular mechanisms related to TEG’s effect on bacterial function remained poorly understood. In the present study, S. mutans UA159 was incubated with clinically relevant concentrations of TEG at pH 5.5 and 7.0. Quantitative real-time PCR, proteomics analysis, and glucosyltransferase enzyme (GTF) activity measurements were employed to identify the bacterial phenotypic response to TEG. A S. mutans vicK isogenic mutant (SMΔvicK1) and its associated complemented strain (SMΔvicK1C), an important regulatory gene for biofilm-associated genes, were used to determine if this signaling pathway was involved in modulation of the S. mutans virulence-associated genes. Extracted proteins from S. mutans biofilms grown in the presence and absence of TEG were subjected to mass spectrometry for protein identification, characterization and quantification. TEG up-regulated gtfB/C, gbpB, comC, comD and comE more significantly in biofilms at cariogenic pH (5.5) and defined concentrations. Differential response of the vicK knock-out (SMΔvicK1) and complemented strains (SMΔvicK1C) implicated this signalling pathway in TEG-modulated cellular responses. TEG resulted in increased GTF enzyme activity, responsible for synthesizing insoluble glucans involved in the formation of cariogenic biofilms. As well, TEG increased protein abundance related to biofilm formation, carbohydrate transport, acid tolerance, and stress-response. Proteomics data was consistent with gene expression findings for the selected genes. These findings demonstrate a mechanistic pathway by which TEG derived from commercial resin materials in the oral cavity promote S. mutans pathogenicity, which is typically associated with secondary caries.
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Affiliation(s)
- Lida Sadeghinejad
- Dental Research Institute, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Dennis G. Cvitkovitch
- Dental Research Institute, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Walter L. Siqueira
- Schulich Dentistry and Department of Biochemistry, University of Western Ontario, London, Ontario, Canada
| | - J. Paul Santerre
- Dental Research Institute, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Yoav Finer
- Dental Research Institute, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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Understanding the Streptococcus mutans Cid/Lrg System through CidB Function. Appl Environ Microbiol 2016; 82:6189-6203. [PMID: 27520814 DOI: 10.1128/aem.01499-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 08/05/2016] [Indexed: 01/09/2023] Open
Abstract
The Streptococcus mutans lrgAB and cidAB operons have been previously described as a potential model system to dissect the complexity of biofilm development and virulence of S. mutans Herein, we have attempted to further characterize the Cid/Lrg system by focusing on CidB, which has been shown to be critical for the ability of S. mutans to survive and persist in a nonpreferred oxygen-enriched condition. We have found that the expression level of cidB is critical to oxidative stress tolerance of S. mutans, most likely by impacting lrg expression. Intriguingly, the impaired aerobic growth phenotype of the cidB mutant could be restored by the additional loss of either CidA or LrgA. Growth-dependent expression of cid and lrg was demonstrated to be tightly under the control of both CcpA and the VicKR two-component system (TCS), regulators known to play an essential role in controlling major catabolic pathways and cell envelope homeostasis, respectively. RNA sequencing (RNA-Seq) analysis revealed that mutation of cidB resulted in global gene expression changes, comprising major domains of central metabolism and virulence processes, particularly in those involved with oxidative stress resistance. Loss of CidB also significantly changed the expression of genes related to genomic islands (GI) TnSmu1 and TnSmu2, the CRISPR (clustered regularly interspaced short palindromic repeats)-Cas system, and toxin-antitoxin (T/A) modules. Taken together, these data show that CidB impinges on the stress response, as well as the fundamental cellular physiology of S. mutans, and further suggest a potential link between Cid/Lrg-mediated cellular processes, S. mutans pathogenicity, and possible programmed growth arrest and cell death mechanisms. IMPORTANCE The ability of Streptococcus mutans to survive a variety of harmful or stressful conditions and to emerge as a numerically significant member of stable oral biofilm communities are essential elements for its persistence and cariogenicity. In this study, the homologous cidAB and lrgAB operons, previously identified as being highly balanced and coordinated during S. mutans aerobic growth, were further characterized through the functional and transcriptomic analysis of CidB. Precise control of CidB levels is shown to impact the expression of lrg, oxidative stress tolerance, major metabolic domains, and the molecular modules linked to cell death and lysis. This study advances our understanding of the Cid/Lrg system as a key player in the integration of complex environmental signals (such as oxidative stress) into the regulatory networks that modulate S. mutans virulence and cell homeostasis.
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Kaspar J, Kim JN, Ahn SJ, Burne RA. An Essential Role for (p)ppGpp in the Integration of Stress Tolerance, Peptide Signaling, and Competence Development in Streptococcus mutans. Front Microbiol 2016; 7:1162. [PMID: 27516759 PMCID: PMC4963387 DOI: 10.3389/fmicb.2016.01162] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 07/12/2016] [Indexed: 11/25/2022] Open
Abstract
The microbes that inhabit the human oral cavity are subjected to constant fluctuations in their environment. To overcome these challenges and gain a competitive advantage, oral streptococci employ numerous adaptive strategies, many of which appear to be intertwined with the development of genetic competence. Here, we demonstrate that the regulatory circuits that control development of competence in Streptococcus mutans, a primary etiological agent of human dental caries, are integrated with key stress tolerance pathways by the molecular alarmone (p)ppGpp. We first observed that the growth of a strain that does not produce (p)ppGpp (ΔrelAPQ, (p)ppGpp0) is not sensitive to growth inhibition by comXinducing peptide (XIP), unlike the wild-type strain UA159, even though XIP-dependent activation of the alternative sigma factor comX by the ComRS pathway is not impaired in the (p)ppGpp0 strain. Overexpression of a (p)ppGpp synthase gene (relP) in the (p)ppGpp0 mutant restored growth inhibition by XIP. We also demonstrate that exposure to micromolar concentrations of XIP elicited changes in (p)ppGpp accumulation in UA159. Loss of the RelA/SpoT homolog (RSH) enzyme, RelA, lead to higher basal levels of (p)ppGpp accumulation, but to decreased sensitivity to XIP and to decreases in comR promoter activity and ComX protein levels. By introducing single amino acid substitutions into the RelA enzyme, the hydrolase activity of the enzyme was shown to be crucial for full com gene induction and transformation by XIP. Finally, loss of relA resulted in phenotypic changes to ΔrcrR mutants, highlighted by restoration of transformation and ComX protein production in the otherwise non-transformable ΔrcrR-NP mutant. Thus, RelA activity and its influence on (p)ppGpp pools appears to modulate competence signaling and development through RcrRPQ and the peptide effectors encoded within rcrQ. Collectively, this study provides new insights into the molecular mechanisms that integrate intercellular communication with the physiological status of the cells and the regulation of key virulence-related phenotypes in S. mutans.
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Affiliation(s)
- Justin Kaspar
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville FL, USA
| | - Jeong N Kim
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville FL, USA
| | - Sang-Joon Ahn
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville FL, USA
| | - Robert A Burne
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville FL, USA
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Effects of Carbohydrate Source on Genetic Competence in Streptococcus mutans. Appl Environ Microbiol 2016; 82:4821-4834. [PMID: 27260355 DOI: 10.1128/aem.01205-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 05/25/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The capacity to internalize and catabolize carbohydrates is essential for dental caries pathogens to persist and cause disease. The expression of many virulence-related attributes by Streptococcus mutans, an organism strongly associated with human dental caries, is influenced by the peptide signaling pathways that control genetic competence. Here, we demonstrate a relationship between the efficiency of competence signaling and carbohydrate source. A significant increase in the activity of the promoters for comX, comS, and comYA after exposure to competence-stimulating peptide (CSP) was observed in cells growing on fructose, maltose, sucrose, or trehalose as the primary carbohydrate source, compared to cells growing on glucose. However, only cells grown in the presence of trehalose or sucrose displayed a significant increase in transformation frequency. Notably, even low concentrations of these carbohydrates in the presence of excess glucose could enhance the expression of comX, encoding a sigma factor needed for competence, and the effects on competence were dependent on the cognate sugar:phosphotransferase permease for each carbohydrate. Using green fluorescent protein (GFP) reporter fusions, we observed that growth in fructose or trehalose resulted in a greater proportion of the population activating expression of comX and comS, encoding the precursor of comX-inducing peptide (XIP), after addition of CSP, than growth in glucose. Thus, the source of carbohydrate significantly impacts the stochastic behaviors that regulate subpopulation responses to CSP, which can induce competence in S. mutans IMPORTANCE The signaling pathways that regulate development of genetic competence in Streptococcus mutans are intimately intertwined with the pathogenic potential of the organism, impacting biofilm formation, stress tolerance, and expression of known virulence determinants. Induction of the gene for the master regulator of competence, ComX, by competence-stimulating peptide (CSP) occurs in a subpopulation of cells. Here, we show that certain carbohydrates that are common in the human diet enhance the ability of CSP to activate transcription of comX and that a subset of these carbohydrates stimulates progression to the competent state. The cognate sugar:phosphotransferase permeases for each sugar are needed for these effects. Interestingly, single-cell analysis shows that the carbohydrates that increase com gene expression do so by enhancing the proportion of cells that respond to CSP. A mathematical model is developed to explain how carbohydrates modulate bistable behavior in the system via the ComRS pathway and ComX stability.
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Li M, Huang R, Zhou X, Qiu W, Xu X, Gregory RL. Effect of nicotine on cariogenic virulence of Streptococcus mutans. Folia Microbiol (Praha) 2016; 61:505-512. [PMID: 27381088 DOI: 10.1007/s12223-016-0465-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 06/30/2016] [Indexed: 02/05/2023]
Abstract
Nicotine has well-documented effects on the growth and colonization of Streptococcus mutans. This study attempts to investigate the effects of nicotine on pathogenic factors of S. mutans, such as the effect on biofilm formation and viability, expression of pathogenic genes, and metabolites of S. mutans. The results demonstrated that addition of nicotine did not significantly influence the viability of S. mutans cells. The biofilms became increasingly compact as the concentrations of nicotine increased. The expression of virulence genes, such as ldh and phosphotransferase system (PTS)-associated genes, was upregulated, and nlmC was upregulated significantly, while ftf was downregulated. The lactate concentration of S. mutans grown in 1 mg/mL of nicotine was increased up to twofold over either biofilm or planktonic cells grown without nicotine. Changes in the metabolites involved in central carbon metabolism from sucrose indicated that most selected metabolites were detectable and influenced by increased concentrations of nicotine. This study demonstrated that nicotine can influence the pathogenicity of S. mutans and may lead to increased dental caries through the production of more lactate and the upregulation of virulence genes.
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Affiliation(s)
- Mingyun Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, No. 14, 3rd Section of Ren Min Nan Rd, Chengdu, Sichuan, 610041, China. .,Department of Biomedical and Applied Sciences, School of Dentistry, Indiana University, 1121 W. Michigan Street, Indianapolis, IN, 46202, USA.
| | - Ruijie Huang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, No. 14, 3rd Section of Ren Min Nan Rd, Chengdu, Sichuan, 610041, China.,Department of Biomedical and Applied Sciences, School of Dentistry, Indiana University, 1121 W. Michigan Street, Indianapolis, IN, 46202, USA.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, No. 14, 3rd Section of Ren Min Nan Rd, Chengdu, Sichuan, 610041, China
| | - Wei Qiu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, No. 14, 3rd Section of Ren Min Nan Rd, Chengdu, Sichuan, 610041, China
| | - Xin Xu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, No. 14, 3rd Section of Ren Min Nan Rd, Chengdu, Sichuan, 610041, China
| | - Richard L Gregory
- Department of Biomedical and Applied Sciences, School of Dentistry, Indiana University, 1121 W. Michigan Street, Indianapolis, IN, 46202, USA. .,Department of Pathology and Laboratory Medicine, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA.
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