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Banerjee A, Kang CY, An M, Koff BB, Sunder S, Kumar A, Tenuta LMA, Stockbridge RB. Fluoride export is required for the competitive fitness of pathogenic microorganisms in dental biofilm models. mBio 2024; 15:e0018424. [PMID: 38624207 PMCID: PMC11077948 DOI: 10.1128/mbio.00184-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 03/20/2024] [Indexed: 04/17/2024] Open
Abstract
Microorganisms resist fluoride toxicity using fluoride export proteins from one of several different molecular families. Cariogenic species Streptococcus mutans and Candida albicans extrude intracellular fluoride using a CLCF F-/H+ antiporter and FEX fluoride channel, respectively, whereas oral commensal eubacteria, such as Streptococcus gordonii, export fluoride using a Fluc fluoride channel. In this work, we examine how genetic knockout of fluoride export impacts pathogen fitness in single-species and three-species dental biofilm models. For biofilms generated using S. mutans with the genetic knockout of the CLCF transporter, exposure to low fluoride concentrations decreased S. mutans counts, synergistically reduced the populations of C. albicans, increased the relative proportion of oral commensal S. gordonii, and reduced properties associated with biofilm pathogenicity, including acid production and hydroxyapatite dissolution. Biofilms prepared with C. albicans with genetic knockout of the FEX channel also exhibited reduced fitness in the presence of fluoride but to a lesser degree. Imaging studies indicate that S. mutans is highly sensitive to fluoride, with the knockout strain undergoing complete lysis when exposed to low fluoride for a moderate amount of time. Biochemical purification of the S. mutans CLCF transporter and functional reconstitution establishes that the functional protein is a dimer encoded by a single gene. Together, these findings suggest that fluoride export by oral pathogens can be targeted by specific inhibitors to restore biofilm symbiosis in dental biofilms and that S. mutans is especially susceptible to fluoride toxicity. IMPORTANCE Dental caries is a globally prevalent condition that occurs when pathogenic species, including Streptococcus mutans and Candida albicans, outcompete beneficial species, such as Streptococcus gordonii, in the dental biofilm. Fluoride is routinely used in oral hygiene to prevent dental caries. Fluoride also has antimicrobial properties, although most microbes possess fluoride exporters to resist its toxicity. This work shows that sensitization of cariogenic species S. mutans and C. albicans to fluoride by genetic knockout of fluoride exporters alters the microbial composition and pathogenic properties of dental biofilms. These results suggest that the development of drugs that inhibit fluoride exporters could potentiate the anticaries effect of fluoride in over-the-counter products like toothpaste and mouth rinses. This is a novel strategy to treat dental caries.
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Affiliation(s)
- Aditya Banerjee
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Chia-Yu Kang
- Program in Biophysics, University of Michigan, Ann Arbor, Michigan, USA
| | - Minjun An
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - B. Ben Koff
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Sham Sunder
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Anuj Kumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Randy B. Stockbridge
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
- Program in Biophysics, University of Michigan, Ann Arbor, Michigan, USA
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Banerjee A, Kang CY, An M, Koff BB, Sunder S, Kumar A, Tenuta LMA, Stockbridge RB. Fluoride export is required for competitive fitness of pathogenic microorganisms in dental biofilm models. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.18.576223. [PMID: 38293214 PMCID: PMC10827179 DOI: 10.1101/2024.01.18.576223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Microorganisms resist fluoride toxicity using fluoride export proteins from one of several different molecular families. Cariogenic species Streptococcus mutans and Candida albicans extrude intracellular fluoride using a CLCF F-/H+ antiporter and FEX fluoride channel, respectively, whereas commensal eubacteria, such as Streptococcus gordonii, export fluoride using a Fluc fluoride channel. In this work, we examine how genetic knockout of fluoride export impacts pathogen fitness in single-species and three-species dental biofilm models. For biofilms generated using S. mutans with genetic knockout of the CLCF transporter, exposure to low fluoride concentrations decreased S. mutans counts, synergistically reduced the populations of C. albicans, increased the relative proportion of commensal S. gordonii, and reduced properties associated with biofilm pathogenicity, including acid production and hydroxyapatite dissolution. Biofilms prepared with C. albicans with genetic knockout of the FEX channel also exhibited reduced fitness in the presence of fluoride, but to a lesser degree. Imaging studies indicate that S. mutans is highly sensitive to fluoride, with the knockout strain undergoing complete lysis when exposed to low fluoride for a moderate amount of time, and biochemical purification the S. mutans CLCF transporter and functional reconstitution establishes that the functional protein is a dimer encoded by a single gene. Together, these findings suggest that fluoride export by oral pathogens can be targeted by specific inhibitors to restore biofilm symbiosis in dental biofilms, and that S. mutans is especially susceptible to fluoride toxicity.
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Affiliation(s)
- Aditya Banerjee
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Chia-Yu Kang
- Program in Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Minjun An
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - B. Ben Koff
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sham Sunder
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Anuj Kumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Randy B. Stockbridge
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Program in Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
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Park L, Kim HS, Jang W, Ji MK, Ryu JH, Cho H, Lim HP. Antibacterial Evaluation of Zirconia Coated with Plasma-Based Graphene Oxide with Photothermal Properties. Int J Mol Sci 2023; 24:ijms24108888. [PMID: 37240234 DOI: 10.3390/ijms24108888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/01/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
The alternative antibacterial treatment photothermal therapy (PTT) significantly affects oral microbiota inactivation. In this work, graphene with photothermal properties was coated on a zirconia surface using atmospheric pressure plasma, and then the antibacterial properties against oral bacteria were evaluated. For the graphene oxide coating on the zirconia specimens, an atmospheric pressure plasma generator (PGS-300, Expantech, Suwon, Republic of Korea) was used, and an Ar/CH4 gas mixture was coated on a zirconia specimen at a power of 240 W and a rate of 10 L/min. In the physiological property test, the surface properties were evaluated by measuring the surface shape of the zirconia specimen coated with graphene oxide, as well as the chemical composition and contact angle of the surface. In the biological experiment, the degree of adhesion of Streptococcus mutans (S. mutans) and Porphyromonas gingivalis (P. gingivalis) was determined by crystal violet assay and live/dead staining. All statistical analyzes were performed using SPSS 21.0 (SPSS Inc., Chicago, IL, USA). The group in which the zirconia specimen coated with graphene oxide was irradiated with near-infrared rays demonstrated a significant reduction in the adhesion of S. mutans and P. gingivalis compared with the group not irradiated. The oral microbiota inactivation was reduced by the photothermal effect on the zirconia coated with graphene oxide, exhibiting photothermal properties.
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Affiliation(s)
- Lydia Park
- Department of Prosthodontics, School of Dentistry, Chonnam National University, 33 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
| | - Hee-Seon Kim
- Department of Prosthodontics, School of Dentistry, Chonnam National University, 33 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
| | - Woohyung Jang
- Department of Prosthodontics, School of Dentistry, Chonnam National University, 33 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
| | - Min-Kyung Ji
- Dental 4D Research Center, Chonnam National University, 33 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
| | - Je-Hwang Ryu
- Department of Pharmacology and Dental Therapeutics, School of Dentistry, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
| | - Hoonsung Cho
- School of Materials Science & Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
| | - Hyun-Pil Lim
- Department of Prosthodontics, School of Dentistry, Chonnam National University, 33 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
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Rose M, Wilson N, Williams E, Letner H, Bettinger R, Bouchendouka A, Batagower J, Kaspar J. Growth with Commensal Streptococci Alters Streptococcus mutans Behaviors. J Dent Res 2023; 102:450-458. [PMID: 36688378 PMCID: PMC10154915 DOI: 10.1177/00220345221145906] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
As oral bacteria grow and persist within biofilms attached to the tooth's surface, they interact with other species to form synergistic or antagonistic exchanges that govern homeostasis for the overall population. One example are the interactions between the cariogenic species Streptococcus mutans and oral commensal streptococci. Previously, we showed that the cell-cell signaling pathways of S. mutans were inhibited during coculture with other oral streptococci species, leading us to posit that the S. mutans transcriptome and behaviors are broadly altered during growth with these species. To test this hypothesis, we performed whole transcriptome sequencing (RNA-seq) on cocultures of S. mutans with either Streptococcus gordonii, Streptococcus sanguinis, or Streptococcus oralis and a quadculture containing all 4 species in comparison to S. mutans grown alone. Our results reveal that in addition to species-dependent changes to the S. mutans transcriptome, a conserved response to oral streptococci in general can be observed. We monitored the behavior of S. mutans by both microscopy imaging of biofilms and in a bacteriocin overlay assay and verified that S. mutans acts similarly with each of these species but noted divergences in phenotypes when cocultured with another cariogenic Streptococcus (Streptococcus sobrinus) or with oral nonstreptococci species. RNA-seq with oral nonstreptococci showed lack of a consistent gene expression profile and overlap of differentially expressed genes found with commensal streptococci. Finally, we investigated the role of upregulated S. mutans genes within our data sets to determine if they provided a fitness benefit during interspecies interactions. Eleven total genes were studied, and we found that a majority impacted the fitness of S. mutans in various assays, highlighted by increased biomass of commensal streptococci in mixed-species biofilms. These results confirm a common, species-independent modification of S. mutans behaviors with oral commensal streptococci that emphasizes the need to further evaluate oral bacteria within multispecies settings.
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Affiliation(s)
- M. Rose
- Division of Biosciences, The Ohio State
University College of Dentistry, Columbus, OH, USA
| | - N. Wilson
- Division of Biosciences, The Ohio State
University College of Dentistry, Columbus, OH, USA
| | - E. Williams
- Division of Biosciences, The Ohio State
University College of Dentistry, Columbus, OH, USA
| | - H. Letner
- Division of Biosciences, The Ohio State
University College of Dentistry, Columbus, OH, USA
| | - R. Bettinger
- Division of Biosciences, The Ohio State
University College of Dentistry, Columbus, OH, USA
| | - A. Bouchendouka
- Division of Biosciences, The Ohio State
University College of Dentistry, Columbus, OH, USA
| | - J. Batagower
- Division of Biosciences, The Ohio State
University College of Dentistry, Columbus, OH, USA
| | - J.R. Kaspar
- Division of Biosciences, The Ohio State
University College of Dentistry, Columbus, OH, USA
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Krieger MC, Merritt J, Raghavan R. Genome-Wide Identification of Novel sRNAs in Streptococcus mutans. J Bacteriol 2022; 204:e0057721. [PMID: 35285723 PMCID: PMC9017351 DOI: 10.1128/jb.00577-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/10/2022] [Indexed: 11/20/2022] Open
Abstract
Streptococcus mutans is a major pathobiont involved in the development of dental caries. Its ability to utilize numerous sugars and to effectively respond to environmental stress promotes S. mutans proliferation in oral biofilms. Because of their quick action and low energetic cost, noncoding small RNAs (sRNAs) represent an ideal mode of gene regulation in stress response networks, yet their roles in oral pathogens have remained largely unexplored. We identified 15 novel sRNAs in S. mutans and show that they respond to four stress-inducing conditions commonly encountered by the pathogen in human mouth: sugar-phosphate stress, hydrogen peroxide exposure, high temperature, and low pH. To better understand the role of sRNAs in S. mutans, we further explored the function of the novel sRNA SmsR4. Our data demonstrate that SmsR4 regulates the enzyme IIA (EIIA) component of the sorbitol phosphotransferase system, which transports and phosphorylates the sugar alcohol sorbitol. The fine-tuning of EIIA availability by SmsR4 likely promotes S. mutans growth while using sorbitol as the main carbon source. Our work lays a foundation for understanding the role of sRNAs in regulating gene expression in stress response networks in S. mutans and highlights the importance of the underexplored phenomenon of posttranscriptional gene regulation in oral bacteria. IMPORTANCE Small RNAs (sRNAs) are important gene regulators in bacteria, but the identities and functions of sRNAs in Streptococcus mutans, the principal bacterium involved in the formation of dental caries, are unknown. In this study, we identified 15 putative sRNAs in S. mutans and show that they respond to four common stress-inducing conditions present in human mouth: sugar-phosphate stress, hydrogen peroxide exposure, high temperature, and low pH. We further show that the novel sRNA SmsR4 likely modulates sorbitol transport into the cell by regulating SMU_313 mRNA, which encodes the EIIA subunit of the sorbitol phosphotransferase system. Gaining a better understanding of sRNA-based gene regulation may provide new opportunities to develop specific inhibitors of S. mutans growth, thereby improving oral health.
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Affiliation(s)
- Madeline C. Krieger
- Department of Biology, Portland State University, Portland, Oregon, USA
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, Oregon, USA
| | - Justin Merritt
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, Oregon, USA
| | - Rahul Raghavan
- Department of Biology, Portland State University, Portland, Oregon, USA
- Department of Molecular Microbiology and Immunology, The University of Texas at San Antonio, San Antonio, Texas, USA
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6
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Transcriptomic Stress Response in Streptococcus mutans following Treatment with a Sublethal Concentration of Chlorhexidine Digluconate. Microorganisms 2022; 10:microorganisms10030561. [PMID: 35336136 PMCID: PMC8950716 DOI: 10.3390/microorganisms10030561] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 01/27/2023] Open
Abstract
Despite the widespread use of antiseptics such as chlorhexidine digluconate (CHX) in dental practice and oral care, the risks of potential resistance toward these antimicrobial compounds in oral bacteria have only been highlighted very recently. Since the molecular mechanisms behind antiseptic resistance or adaptation are not entirely clear and the bacterial stress response has not been investigated systematically so far, the aim of the present study was to investigate the transcriptomic stress response in Streptococcus mutans after treatment with CHX using RNA sequencing (RNA-seq). Planktonic cultures of stationary-phase S. mutans were treated with a sublethal dose of CHX (125 µg/mL) for 5 min. After treatment, RNA was extracted, and RNA-seq was performed on an Illumina NextSeq 500. Differentially expressed genes were analyzed and validated by qRT-PCR. Analysis of differential gene expression following pathway analysis revealed a considerable number of genes and pathways significantly up- or downregulated in S. mutans after sublethal treatment with CHX. In summary, the expression of 404 genes was upregulated, and that of 271 genes was downregulated after sublethal CHX treatment. Analysis of differentially expressed genes and significantly regulated pathways showed regulation of genes involved in purine nucleotide synthesis, biofilm formation, transport systems and stress responses. In conclusion, the results show a transcriptomic stress response in S. mutans upon exposure to CHX and offer insight into potential mechanisms that may result in development of resistances.
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Zhang K, Xiang Y, Peng Y, Tang F, Cao Y, Xing Z, Li Y, Liao X, Sun Y, He Y, Ye Q. Influence of Fluoride-Resistant Streptococcus mutans Within Antagonistic Dual-Species Biofilms Under Fluoride In Vitro. Front Cell Infect Microbiol 2022; 12:801569. [PMID: 35295758 PMCID: PMC8918626 DOI: 10.3389/fcimb.2022.801569] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 01/20/2022] [Indexed: 11/13/2022] Open
Abstract
The widespread application of fluoride, an extremely effective caries prevention agent, induces the generation of fluoride-resistant strains of opportunistic cariogenic bacteria such as fluoride-resistant Streptococcus mutans (S. mutans). However, the influence of this fluoride-resistant strain on oral microecological homeostasis under fluoride remains unknown. In this study, an antagonistic dual-species biofilm model composed of S. mutans and Streptococcus sanguinis (S. sanguinis) was used to investigate the influence of fluoride-resistant S. mutans on dual-species biofilm formation and pre-formed biofilms under fluoride to further elucidate whether fluoride-resistant strains would influence the anti-caries effect of fluoride from the point of biofilm control. The ratio of bacteria within dual-species biofilms was investigated using quantitative real-time PCR and fluorescence in situ hybridization. Cristal violet staining, scanning electron microscopy imaging, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay were used to evaluate biofilm biomass, biofilm structure, and metabolic activity, respectively. Biofilm acidogenicity was determined using lactic acid and pH measurements. The anthrone method and exopolysaccharide (EPS) staining were used to study the EPS production of biofilms. We found that, in biofilm formation, fluoride-resistant S. mutans occupied an overwhelming advantage in dual-species biofilms under fluoride, thus showing more biofilm biomass, more robust biofilm structure, and stronger metabolic activity (except for 0.275 g/L sodium fluoride [NaF]), EPS production, and acidogenicity within dual-species biofilms. However, in pre-formed biofilms, the advantage of fluoride-resistant S. mutans could not be fully highlighted for biofilm formation. Therefore, fluoride-resistant S. mutans could influence the anti-caries effect of fluoride on antagonistic dual-species biofilm formation while being heavily discounted in pre-formed biofilms from the perspective of biofilm control.
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Affiliation(s)
- Keke Zhang
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yangfan Xiang
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Youjian Peng
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan, China
| | - Fengyu Tang
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yanfan Cao
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Zhenjie Xing
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yejian Li
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Xiangyan Liao
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yan Sun
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yan He
- Tianyou Hospital, Wuhan University of Science and Technology, Wuhan, China
- *Correspondence: Qingsong Ye, ; Yan He,
| | - Qingsong Ye
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan, China
- *Correspondence: Qingsong Ye, ; Yan He,
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Huang Y, Wurihan W, Lu B, Zou Y, Wang Y, Weldon K, Fondell JD, Lai Z, Wu X, Fan H. Robust Heat Shock Response in Chlamydia Lacking a Typical Heat Shock Sigma Factor. Front Microbiol 2022; 12:812448. [PMID: 35046926 PMCID: PMC8762339 DOI: 10.3389/fmicb.2021.812448] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 12/02/2021] [Indexed: 11/13/2022] Open
Abstract
Cells reprogram their transcriptome in response to stress, such as heat shock. In free-living bacteria, the transcriptomic reprogramming is mediated by increased DNA-binding activity of heat shock sigma factors and activation of genes normally repressed by heat-induced transcription factors. In this study, we performed transcriptomic analyses to investigate heat shock response in the obligate intracellular bacterium Chlamydia trachomatis, whose genome encodes only three sigma factors and a single heat-induced transcription factor. Nearly one-third of C. trachomatis genes showed statistically significant (≥1.5-fold) expression changes 30 min after shifting from 37 to 45°C. Notably, chromosomal genes encoding chaperones, energy metabolism enzymes, type III secretion proteins, as well as most plasmid-encoded genes, were differentially upregulated. In contrast, genes with functions in protein synthesis were disproportionately downregulated. These findings suggest that facilitating protein folding, increasing energy production, manipulating host activities, upregulating plasmid-encoded gene expression, and decreasing general protein synthesis helps facilitate C. trachomatis survival under stress. In addition to relieving negative regulation by the heat-inducible transcriptional repressor HrcA, heat shock upregulated the chlamydial primary sigma factor σ66 and an alternative sigma factor σ28. Interestingly, we show for the first time that heat shock downregulates the other alternative sigma factor σ54 in a bacterium. Downregulation of σ54 was accompanied by increased expression of the σ54 RNA polymerase activator AtoC, thus suggesting a unique regulatory mechanism for reestablishing normal expression of select σ54 target genes. Taken together, our findings reveal that C. trachomatis utilizes multiple novel survival strategies to cope with environmental stress and even to replicate. Future strategies that can specifically target and disrupt Chlamydia’s heat shock response will likely be of therapeutic value.
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Affiliation(s)
- Yehong Huang
- Department of Parasitology, Xiangya School of Basic Medicine, Central South University, Changsha, China.,Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Wurihan Wurihan
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Bin Lu
- Department of Parasitology, Xiangya School of Basic Medicine, Central South University, Changsha, China.,Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Yi Zou
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Yuxuan Wang
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Korri Weldon
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Joseph D Fondell
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Zhao Lai
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, TX, United States.,Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Xiang Wu
- Department of Parasitology, Xiangya School of Basic Medicine, Central South University, Changsha, China
| | - Huizhou Fan
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
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Serrage HJ, Jepson MA, Rostami N, Jakubovics NS, Nobbs AH. Understanding the Matrix: The Role of Extracellular DNA in Oral Biofilms. FRONTIERS IN ORAL HEALTH 2022; 2:640129. [PMID: 35047995 PMCID: PMC8757797 DOI: 10.3389/froh.2021.640129] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 02/09/2021] [Indexed: 12/13/2022] Open
Abstract
Dental plaque is the key etiological agent in caries formation and the development of the prevalent chronic oral inflammatory disease, periodontitis. The dental plaque biofilm comprises a diverse range of microbial species encased within a rich extracellular matrix, of which extracellular DNA (eDNA) has been identified as an important component. The molecular mechanisms of eDNA release and the structure of eDNA have yet to be fully characterized. Nonetheless, key functions that have been proposed for eDNA include maintaining biofilm structural integrity, initiating adhesion to dental surfaces, acting as a nutrient source, and facilitating horizontal gene transfer. Thus, eDNA is a potential therapeutic target for the management of oral disease–associated biofilm. This review aims to summarize advances in the understanding of the mechanisms of eDNA release from oral microorganisms and in the methods of eDNA detection and quantification within oral biofilms.
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Affiliation(s)
- Hannah J Serrage
- Bristol Dental School, University of Bristol, Bristol, United Kingdom
| | - Mark A Jepson
- Wolfson Bioimaging Facility, University of Bristol, Bristol, United Kingdom
| | - Nadia Rostami
- School of Dental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Nicholas S Jakubovics
- School of Dental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Angela H Nobbs
- Bristol Dental School, University of Bristol, Bristol, United Kingdom
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10
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Biswas S, Dhaked HPS, Keightley A, Biswas I. Involvement of ClpE ATPase in Physiology of Streptococcus mutans. Microbiol Spectr 2021; 9:e0163021. [PMID: 34851151 PMCID: PMC8635124 DOI: 10.1128/spectrum.01630-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 11/01/2021] [Indexed: 11/25/2022] Open
Abstract
Streptococcus mutans, a dental pathogen, harbors at least three Clp ATPases (ClpC, ClpE, and ClpX) that form complexes with ClpP protease and participate in regulated proteolysis. Among these, the function of ClpE ATPase is poorly understood. We have utilized an isogenic clpE-deficient strain derived from S. mutans UA159 and evaluated the role of ClpE in cellular physiology. We found that loss of ClpE leads to increased susceptibility against thiol stress but not to oxidative and thermal stress. Furthermore, we found that the mutant displays altered tolerance against some antibiotics and altered biofilm formation. We performed a label-free proteomic analysis by comparing the mutant with the wild-type UA159 strain under nonstressed conditions and found that ClpE modulates a relatively limited proteome in the cell compared to the proteomes modulated by ClpX and ClpP. Nevertheless, we found that ClpE deficiency leads to an overabundance of some cell wall synthesis enzymes, ribosomal proteins, and an unknown protease encoded by SMU.2153. Our proteomic data strongly support some of the stress-related phenotypes that we observed. Our study emphasizes the significance of ClpE in the physiology of S. mutans. IMPORTANCE When bacteria encounter environmental stresses, the expression of various proteins collectively known as heat shock proteins is induced. These heat shock proteins are necessary for cell survival specifically under conditions that induce protein denaturation. A subset of heat shock proteins known as the Clp proteolytic complex is required for the degradation of the misfolded proteins in the cell. The Clp proteolytic complex contains an ATPase and a protease. A specific Clp ATPase, ClpE, is uniquely present in Gram-positive bacteria, including streptococci. Here, we have studied the functional role of the ClpE protein in Streptococcus mutans, a dental pathogen. Our results suggest that ClpE is required for survival under certain antibiotic exposure and stress conditions but not others. Our results demonstrate that loss of ClpE leads to a significantly altered cellular proteome, and the analysis of those changes suggests that ClpE's functions in S. mutans are different from its functions in other Gram-positive bacteria.
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Affiliation(s)
- Saswati Biswas
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Hemendra Pal Singh Dhaked
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Andrew Keightley
- Department of Ophthalmology, University of Missouri School of Medicine, Kansas City, Missouri, USA
| | - Indranil Biswas
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
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Shields RC, Kim JN, Ahn SJ, Burne RA. Peptides encoded in the Streptococcus mutans RcrRPQ operon are essential for thermotolerance. MICROBIOLOGY-SGM 2020; 166:306-317. [PMID: 31935187 DOI: 10.1099/mic.0.000887] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The MarR-like transcriptional regulator and two ABC transporters encoded by the rcrRPQ operon in the dental caries pathogen Streptococcus mutans have important regulatory roles related to oxidative stress tolerance, genetic competence and (p)ppGpp metabolism. A unique feature of the rcrRPQ operon, when compared to other bacteria, is the presence of two peptides, designated Pep1 and Pep2, encoded in alternative reading frames at the 3' end of rcrQ. Here, we show that the rcrRPQ operon, including Pep1 and 2, is essential for S. mutans to survive and maintain viability at elevated temperatures. No major changes in the levels of the heat shock proteins DnaK or GroEL that could account for the thermosensitivity of rcrRPQ mutants were observed. By introducing a single amino acid substitution into the comX gene that deletes an internally encoded peptide, XrpA, we found that XrpA is a contributing factor to the thermosensitive phenotype of a ΔrcrR strain. Overexpression of XrpA on a plasmid also caused a significant growth defect at 42 °C. Interestingly, loss of the gene for the RelA/SpoT homologue (RSH) enzyme, relA, restored growth of the ΔrcrR strain at 42 °C. During heat stress and when a stringent response was induced, levels of (p)ppGpp were elevated in the ΔrcrR strain. Deletion of relA in the ΔrcrR strain lowered the basal levels of (p)ppGpp to those observed in wild-type S. mutans. Thus, (p)ppGpp pools are dysregulated in ΔrcrR, which likely leads to aberrant control of transcriptional/translational processes and the thermosensitive phenotype. In summary, the genes and peptides encoded in the rcrRPQ operon are critical for thermotolerance, and in some strains these phenotypes are related to altered (p)ppGpp metabolism and increased production of the XrpA peptide.
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Affiliation(s)
- Robert C Shields
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, USA
| | - Jeong Nam Kim
- Department of Microbiology, College of Natural Sciences, Pusan National University, Busan 46241, Republic of Korea
| | - Sang-Joon Ahn
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, USA
| | - Robert A Burne
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, USA
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Yu Z, Tao S, Xu HHK, Weir MD, Fan M, Liu Y, Zhou X, Liang K, Li J. Rechargeable adhesive with calcium phosphate nanoparticles inhibited long-term dentin demineralization in a biofilm-challenged environment. J Dent 2020; 104:103529. [PMID: 33189801 DOI: 10.1016/j.jdent.2020.103529] [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: 08/22/2020] [Revised: 10/21/2020] [Accepted: 11/09/2020] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVES This study aims to investigate the long-term demineralization-inhibition capability of a rechargeable adhesive with nanoparticles of amorphous calcium phosphate (NACP) on dentin in a biofilm-challenged environment. METHODS The NACP adhesive was immersed in a pH 4 solution to exhaust calcium (Ca) and phosphate (P) ions and then recharged with Ca and P ions. Dentin samples were demineralized underStreptococcus mutans biofilms for 24 h and randomly divided into two groups: (1) dentin control, (2) dentin with recharged NACP adhesives. Each day, all the samples were immersed in brain heart infusion broth with 1% sucrose (BHIS) for 4 h, and then in artificial saliva (AS) for 20 h. This cycle was repeated for 10 days. The pH of BHIS, the Ca and P ions content of the BHIS and AS were measured daily. After 10 days, the lactic acid production and colony-forming units of the biofilms were tested. The changes of remineralization/demineralization were also analyzed. RESULTS Dentin in the control group showed further demineralization. The recharged NACP adhesive neutralized acids, increasing the pH to above 5, and released large amounts of Ca and P ions each day. The recharged NACP adhesive decreased the production of lactic acid (P < 0.05), inhibited dentin demineralization and sustained the dentin hardness in the biofilm-challenged environment, showing an excellent long-term demineralization-inhibition capability. CONCLUSIONS The NACP adhesive could continuously inhibit dentin demineralization in a biofilm-challenged environment by recharging with Ca and P ions. SIGNIFICANCE The rechargeable NACP adhesive could provide long-term dentin bond protection.
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Affiliation(s)
- Zhaohan Yu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Siying Tao
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Hockin H K Xu
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Michael D Weir
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Menglin Fan
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Yifang Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Kunneng Liang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA.
| | - Jiyao Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
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Nikinmaa S, Alapulli H, Auvinen P, Vaara M, Rantala J, Kankuri E, Sorsa T, Meurman J, Pätilä T. Dual-light photodynamic therapy administered daily provides a sustained antibacterial effect on biofilm and prevents Streptococcus mutans adaptation. PLoS One 2020; 15:e0232775. [PMID: 32374766 PMCID: PMC7202659 DOI: 10.1371/journal.pone.0232775] [Citation(s) in RCA: 17] [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: 01/16/2020] [Accepted: 04/21/2020] [Indexed: 12/19/2022] Open
Abstract
Antibacterial photodynamic therapy (aPDT) and antibacterial blue light (aBL) are emerging treatment methods auxiliary to mechanical debridement for periodontitis. APDT provided with near-infrared (NIR) light in conjunction with an indocyanine green (ICG) photosensitizer has shown efficacy in several dental in-office-treatment protocols. In this study, we tested Streptococcus mutans biofilm sensitivity to either aPDT, aBL or their combination dual-light aPDT (simultaneous aPDT and aBL) exposure. Biofilm was cultured by pipetting diluted Streptococcus mutans suspension with growth medium on the bottom of well plates. Either aPDT (810 nm) or aBL (405 nm) or a dual-light aPDT (simultaneous 810 nm aPDT and 405 nm aBL) was applied with an ICG photosensitizer in cases of aPDT or dual-light, while keeping the total given radiant exposure constant at 100 J/cm2. Single-dose light exposures were given after one-day or four-day biofilm incubations. Also, a model of daily treatment was provided by repeating the same light dose daily on four-day and fourteen-day biofilm incubations. Finally, the antibacterial action of the dual-light aPDT with different energy ratios of 810 nm and 405 nm of light were examined on the single-day and four-day biofilm protocols. At the end of each experiment the bacterial viability was assessed by colony-forming unit method. Separate samples were prepared for confocal 3D biofilm imaging. On a one-day biofilm, the dual-light aPDT was significantly more efficient than aBL or aPDT, although all modalities were bactericidal. On a four-day biofilm, a single exposure of aPDT or dual-light aPDT was more efficient than aBL, resulting in a four logarithmic scale reduction in bacterial counts. Surprisingly, when the same amount of aPDT was repeated daily on a four-day or a fourteen-day biofilm, bacterial viability improved significantly. A similar improvement in bacterial viability was observed after repetitive aBL application. This viability improvement was eliminated when dual-light aPDT was applied. By changing the 405 nm to 810 nm radiant exposure ratio in dual-light aPDT, the increase in aBL improved the antibacterial action when the biofilm was older. In conclusion, when aPDT is administered repeatedly to S. mutans biofilm, a single wavelength-based aBL or aPDT leads to a significant biofilm adaptation and increased S. mutans viability. The combined use of aBL light in synchrony with aPDT arrests the adaptation and provides significantly improved and sustained antibacterial efficacy.
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Affiliation(s)
- Sakari Nikinmaa
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
- Koite Health Oy, Espoo, Finland
| | - Heikki Alapulli
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Petri Auvinen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Martti Vaara
- Northern Antibiotics, Espoo, Finland
- Department of Bacteriology and Immunology, University of Helsinki, Medical School, Helsinki, Finland
| | | | - Esko Kankuri
- Department of Pharmacology, University of Helsinki, Helsinki, Finland
| | - Timo Sorsa
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
- Department of Oral Diseases, Karolinska Institute, Huddinge, Sweden
| | - Jukka Meurman
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Tommi Pätilä
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
- Koite Health Oy, Espoo, Finland
- Department of Congenital Heart Surgery and Organ Transplantation, New Children’s Hospital, University of Helsinki, Helsinki, Finland
- * E-mail:
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14
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Effects of Norspermidine on Dual-Species Biofilms Composed of Streptococcus mutans and Streptococcus sanguinis. BIOMED RESEARCH INTERNATIONAL 2019; 2019:1950790. [PMID: 31781595 PMCID: PMC6874952 DOI: 10.1155/2019/1950790] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 09/30/2019] [Indexed: 02/05/2023]
Abstract
The present study aimed at investigating the influence of norspermidine on the formation of dual-species biofilms composed of Streptococcus mutans (S. mutans) and Streptococcus sanguinis (S. sanguinis). Crystal violet assay was conducted to assess the formation of single-species biofilms of S. mutans and S. sanguinis, and the growth curve was carefully observed to monitor the growth of these two species of bacteria. Fluorescence in situ hybridization (FISH) and MTT array were used to analyze the composition and metabolic activity of the dual-species biofilms, respectively. Extracellular polysaccharides (EPS)/bacteria staining, anthrone method, and scanning electron microscopy (SEM) imaging were conducted to study the synthesis of EPS by dual-species biofilms. Lactic acid assay and pH were measured to detect dual-species biofilm acid production. We found that norspermidine had different effects on S. mutans and S. sanguinis including their growth and biofilm formation. Norspermidine regulated the composition of the dual-species biofilms, decreased the ratio of S. mutans in dual-species biofilms, and reduced the metabolic activity, EPS synthesis, and acid production of dual-species biofilms. Norspermidine regulated dual-species biofilms in an ecological way, suggesting that it may be a potent reagent for controlling dental biofilms and managing dental caries.
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15
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Chen X, Liu C, Peng X, He Y, Liu H, Song Y, Xiong K, Zou L. Sortase A‐mediated modification of the
Streptococcus mutans
transcriptome and virulence traits. Mol Oral Microbiol 2019; 34:219-233. [PMID: 31342653 DOI: 10.1111/omi.12266] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 02/05/2023]
Affiliation(s)
- Xuan Chen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
| | - Chengcheng Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
- Department of Periodontics West China Hospital of Stomatology, Sichuan University Chengdu China
| | - Xian Peng
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
| | - Yuanli He
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
| | - Haixia Liu
- Stomatological Hospital of Chongqing Medical University Chongqing China
| | - Ying Song
- Stomatological Hospital of Chongqing Medical University Chongqing China
| | - Kaixin Xiong
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
| | - Ling Zou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
- Department of Conservation Dentistry and Endodontics West China Hospital of Stomatology, Sichuan University Chengdu China
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16
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Bedoya-Correa CM, Rincón Rodríguez RJ, Parada-Sanchez MT. Genomic and phenotypic diversity of Streptococcus mutans. J Oral Biosci 2019; 61:22-31. [DOI: 10.1016/j.job.2018.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/29/2018] [Accepted: 11/05/2018] [Indexed: 02/03/2023]
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17
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Cornejo Ulloa P, van der Veen MH, Krom BP. Review: modulation of the oral microbiome by the host to promote ecological balance. Odontology 2019; 107:437-448. [PMID: 30719639 PMCID: PMC6732124 DOI: 10.1007/s10266-019-00413-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 01/23/2019] [Indexed: 01/05/2023]
Abstract
The indivisible relationship between the human host and its oral microbiome has been shaped throughout the millennia, by facing various changes that have forced the adaptation of oral microorganisms to new environmental conditions. In this constant crosstalk between the human host and its microbiome, a bidirectional relationship has been established. The microorganisms provide the host with functions it cannot perform on its own and at the same time the host provides its microbes with a suitable environment for their growth and development. These host factors can positively affect the microbiome, promoting diversity and balance between different species, resulting in a state of symbiosis and absence of pathology. In contrast, other host factors can negatively influence the composition of the oral microbiome and drive the interaction towards a dysbiotic state, where the balance tilts towards a harmful relationship between the host and its microbiome. The aim of this review is to describe the role host factors play in cultivating and maintaining a healthy oral ecology and discuss mechanisms that can prevent its drift towards dysbiosis.
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Affiliation(s)
- Pilar Cornejo Ulloa
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, G. Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Monique H van der Veen
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, G. Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands.
| | - Bastiaan P Krom
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, G. Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands.
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18
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Oza S, Patel K, Bhosale S, Mitra R, Gupta R, Choudhary D. To Determine the Effect of Chewing Gum Containing Xylitol and Sorbitol on Mutans Streptococci and Lactobacilli Count in Saliva, Plaque, and Gingival Health and to Compare the Efficacy of Chewing Gums. J Int Soc Prev Community Dent 2018; 8:354-360. [PMID: 30123770 PMCID: PMC6071354 DOI: 10.4103/jispcd.jispcd_54_18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 05/25/2018] [Indexed: 12/23/2022] Open
Abstract
Aims and Objective: The aim of the study is to determine the effect of chewing gum containing xylitol and sorbitol on mutans streptococci and Lactobacilli count in saliva, plaque, and gingival health and to compare the efficacy of chewing gums. Materials and Methods: The study was designed as a double-blinded randomized uncontrolled clinical trial with two parallel arms. A total of 80 students consented and completed the study. The test group (X) received corresponding pellets with xylitol and the control group (S) was given pellets containing sorbitol and maltitol three times daily for 30 days. Clinical scoring and saliva samples were collected at three different intervals, at baseline, 15th, and 30th day of the study. The outcome measure was plaque index score, gingival index score, salivary mutans streptococci, and Lactobacilli counts. Data collected were analyzed using Statistical Package for the Social Sciences (SPSS version 19.0). Results: There was no statistically significant difference between the mean of mutans streptococci count of test and control group at baseline and 15th day, but there was statistically highly significant difference (P = 0.00) between the mean of mutans streptococci count in test and control group on the 30th day. The mean of Lactobacilli count, plaque index, and gingival index score between test and control group showed no statistically significant difference at baseline, 15th day, and 30th day. Conclusion: The results suggest that only xylitol gum may interfere with the mutans streptococci composition and reduce it after continuous use of 30 days effectively as compared to sorbitol gum, but both the gums are equally effective on salivary Lactobacilli, plaque, and gingiva at different intervals.
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Affiliation(s)
- Swapnil Oza
- Department of Public Health Dentistry, Darshan Dental College and Hospital, Udaipur, Rajasthan, India
| | - Kreta Patel
- Department of Public Health Dentistry, Darshan Dental College and Hospital, Udaipur, Rajasthan, India
| | - Satish Bhosale
- Department of Oral Pathology and Microbiology, RR Dental College and Hospital, Udaipur, Rajasthan, India
| | - Ruchi Mitra
- Department of Public Health Dentistry, Darshan Dental College and Hospital, Udaipur, Rajasthan, India
| | - Rupam Gupta
- Department of Public Health Dentistry, Darshan Dental College and Hospital, Udaipur, Rajasthan, India
| | - Divya Choudhary
- Department of Public Health Dentistry, Darshan Dental College and Hospital, Udaipur, Rajasthan, India
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Abstract
Newer research tools and basic science knowledge base have allowed the exploration of endodontic diseases in the pulp and periapical tissues in novel ways. The use of next generation sequencing, bioinformatics analyses, genome-wide association studies, to name just a few of these innovations, has allowed the identification of hundreds of microorganisms and of host response factors. This review addresses recent advances in endodontic microbiology and the host response and discusses the potential for future innovations in this area.
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Affiliation(s)
- Ashraf F Fouad
- Department of Endodontics, School of Dentistry, University of North Carolina at Chapel Hill, 1098 First Dental Building, CB# 7450, Chapel Hill, NC 27599-7450, USA.
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20
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Olwal CO, Ang'ienda PO, Onyango DM, Ochiel DO. Susceptibility patterns and the role of extracellular DNA in Staphylococcus epidermidis biofilm resistance to physico-chemical stress exposure. BMC Microbiol 2018; 18:40. [PMID: 29720089 PMCID: PMC5930741 DOI: 10.1186/s12866-018-1183-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 04/23/2018] [Indexed: 12/18/2022] Open
Abstract
Background Over 65% of human infections are ascribed to bacterial biofilms that are often highly resistant to antibiotics and host immunity. Staphylococcus epidermidis is the predominant cause of recurrent nosocomial and biofilm-related infections. However, the susceptibility patterns of S. epidermidis biofilms to physico-chemical stress induced by commonly recommended disinfectants [(heat, sodium chloride (NaCl), sodium hypochlorite (NaOCl) and hydrogen peroxide (H2O2)] in domestic and human healthcare settings remains largely unknown. Further, the molecular mechanisms of bacterial biofilms resistance to the physico-chemical stresses remain unclear. Growing evidence demonstrates that extracellular DNA (eDNA) protects bacterial biofilms against antibiotics. However, the role of eDNA as a potential mechanism underlying S. epidermidis biofilms resistance to physico-chemical stress exposure is yet to be understood. Therefore, this study aimed to evaluate the susceptibility patterns of and eDNA release by S. epidermidis biofilm and planktonic cells to physico-chemical stress exposure. Results S. epidermidis biofilms exposed to physico-chemical stress conditions commonly recommended for disinfection [heat (60 °C), 1.72 M NaCl, solution containing 150 μL of waterguard (0.178 M NaOCl) in 1 L of water or 1.77 M H2O2] for 30 and 60 min exhibited lower log reductions of CFU/mL than the corresponding planktonic cells (p < 0.0001). The eDNA released by sub-lethal heat (50 °C)-treated S. epidermidis biofilm and planktonic cells was not statistically different (p = 0.8501). However, 50 °C-treated S. epidermidis biofilm cells released significantly increased eDNA than the untreated controls (p = 0.0098). The eDNA released by 0.8 M NaCl-treated S. epidermidis biofilm and planktonic cells was not significantly different (p = 0.9697). Conversely, 5 mM NaOCl-treated S. epidermidis biofilms exhibited significantly increased eDNA release than the corresponding planktonic cells (p = 0.0015). Further, the 50 μM H2O2-treated S. epidermidis biofilms released significantly more eDNA than the corresponding planktonic cells (p = 0.021). Conclusions S. epidermidis biofilms were less susceptible to physico-chemical stress induced by the four commonly recommended disinfectants than the analogous planktonic cells. Further, S. epidermidis biofilms enhanced eDNA release in response to the sub-lethal heat and oxidative stress exposure than the corresponding planktonic cells suggesting a role of eDNA in biofilms resistance to the physico-chemical stresses.
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Affiliation(s)
- Charles Ochieng' Olwal
- Department of Zoology, School of Physical and Biological Sciences, Maseno University, P.O. Box, 333-40105, Maseno, Kenya.
| | - Paul Oyieng' Ang'ienda
- Department of Zoology, School of Physical and Biological Sciences, Maseno University, P.O. Box, 333-40105, Maseno, Kenya
| | - David Miruka Onyango
- Department of Zoology, School of Physical and Biological Sciences, Maseno University, P.O. Box, 333-40105, Maseno, Kenya
| | - Daniel Otieno Ochiel
- Department of Zoology, School of Physical and Biological Sciences, Maseno University, P.O. Box, 333-40105, Maseno, Kenya
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21
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Plasticity of the Pyruvate Node Modulates Hydrogen Peroxide Production and Acid Tolerance in Multiple Oral Streptococci. Appl Environ Microbiol 2018; 84:AEM.01697-17. [PMID: 29079629 DOI: 10.1128/aem.01697-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 10/19/2017] [Indexed: 02/05/2023] Open
Abstract
Commensal Streptococcus sanguinis and Streptococcus gordonii are pioneer oral biofilm colonizers. Characteristic for both is the SpxB-dependent production of H2O2, which is crucial for inhibiting competing biofilm members, especially the cariogenic species Streptococcus mutans H2O2 production is strongly affected by environmental conditions, but few mechanisms are known. Dental plaque pH is one of the key parameters dictating dental plaque ecology and ultimately oral health status. Therefore, the objective of the current study was to characterize the effects of environmental pH on H2O2 production by S. sanguinis and S. gordoniiS. sanguinis H2O2 production was not found to be affected by moderate changes in environmental pH, whereas S. gordonii H2O2 production declined markedly in response to lower pH. Further investigation into the pyruvate node, the central metabolic switch modulating H2O2 or lactic acid production, revealed increased lactic acid levels for S. gordonii at pH 6. The bias for lactic acid production at pH 6 resulted in concomitant improvement in the survival of S. gordonii at low pH and seems to constitute part of the acid tolerance response of S. gordonii Differential responses to pH similarly affect other oral streptococcal species, suggesting that the observed results are part of a larger phenomenon linking environmental pH, central metabolism, and the capacity to produce antagonistic amounts of H2O2IMPORTANCE Oral biofilms are subject to frequent and dramatic changes in pH. S. sanguinis and S. gordonii can compete with caries- and periodontitis-associated pathogens by generating H2O2 Therefore, it is crucial to understand how S. sanguinis and S. gordonii adapt to low pH and maintain their competitiveness under acid stress. The present study provides evidence that certain oral bacteria respond to environmental pH changes by tuning their metabolic output in favor of lactic acid production, to increase their acid survival, while others maintain their H2O2 production at a constant level. The differential control of H2O2 production provides important insights into the role of environmental conditions for growth competition of the oral flora.
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22
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Chen C, Li Q, Wang Q, Lu D, Zhang H, Wang J, Fu R. Transcriptional profiling provides new insights into the role of nitric oxide in enhancing Ganoderma oregonense resistance to heat stress. Sci Rep 2017; 7:15694. [PMID: 29146915 PMCID: PMC5691203 DOI: 10.1038/s41598-017-15340-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 10/26/2017] [Indexed: 12/18/2022] Open
Abstract
Ganoderma is well known for its use in traditional Chinese medicine and is widely cultivated in China, Korea, and Japan. Increased temperatures associated with global warming are negatively influencing the growth and development of Ganoderma. Nitric oxide is reported to play an important role in alleviating fungal heat stress (HS). However, the transcriptional profiling of Ganoderma oregonense in response to HS, as well as the transcriptional response regulated by NO to cope with HS has not been reported. We used RNA-Seq technology to generate large-scale transcriptome data from G. oregonense mycelia subjected to HS (32 °C) and exposed to concentrations of exogenous NO. The results showed that heat shock proteins (HSPs), "probable stress-induced proteins", and unigenes involved in "D-amino-acid oxidase activity" and "oxidoreductase activity" were significantly up-regulated in G. oregonense subjected to HS (P < 0.05). The significantly up-regulated HSPs, "monooxygenases", "alcohol dehydrogenase", and "FAD/NAD(P)-binding domain-containing proteins" (P < 0.05) regulated by exogenous NO may play important roles in the enhanced HS tolerance of G. oregonense. These results provide insights into the transcriptional response of G. oregonense to HS and the mechanism by which NO enhances the HS tolerance of fungi at the gene expression level.
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Affiliation(s)
- Cheng Chen
- Institute of plant protection, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, P.R. China
| | - Qiang Li
- Biotechnology and Nuclear Technology Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu, 610061, Sichuan, P.R. China.,Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, P.R. China
| | - Qiangfeng Wang
- Biotechnology and Nuclear Technology Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu, 610061, Sichuan, P.R. China
| | - Daihua Lu
- Institute of plant protection, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, P.R. China
| | - Hong Zhang
- Institute of plant protection, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, P.R. China. .,Sichuan Academy of Agricultural Sciences, 20 # Jingjusi Rd, Chengdu, 610066, Sichuan, China.
| | - Jian Wang
- Institute of plant protection, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, P.R. China
| | - Rongtao Fu
- Institute of plant protection, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, P.R. China
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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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Abstract
The heat shock response is crucial for organisms against heat-damaged proteins and maintaining homeostasis at a high temperature. Heterologous expression of eukaryotic molecular chaperones protects Escherichia coli from heat stress. Here we report that expression of the plant E3 ligase BnTR1 significantly increases the thermotolerance of E. coli. Different from eukaryotic chaperones, BnTR1 expression induces the accumulation of heat shock factor σ32 and heat shock proteins. The active site of BnTR1 in E. coli is the zinc fingers of the RING domain, which interacts with DnaK resulting in stabilizing σ32. Our findings indicate the expression of BnTR1 confers thermoprotective effects on E. coli cells, and it may provide useful clues to engineer thermophilic bacterial strains.
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胡 桐, 郑 伟, 李 少, 董 洁, 王 心, 王 成, 邵 宁, 储 冰. [Changes in expressions of sRNA SpR19 and its potential target GroEL in Streptococcus mutans strains with different cariogenicity cultured under different pH conditions]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2017; 37:802-806. [PMID: 28669956 PMCID: PMC6744155 DOI: 10.3969/j.issn.1673-4254.2017.06.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Indexed: 06/07/2023]
Abstract
OBJECTIVE To investigate the changes in the expression level of sRNA SpR19 and its potential target protein GroEL in clinical isolates of Streptococcus mutans with different cariogenicity exposed to different pH conditions and explore the possibility of using these molecules as biomarkers for assessing the cariogenicity of the bacteria. METHODS The total RNAs were extracted from the clinical isolates of Streptococcus mutans with high (strain 17) and low cariogenicity (strain 5) for high-throughput sequencing for profiling of the differentially expressed sRNAs. The candidate sRNA, SpR19, was selected for further study on the basis of bioinformatics analysis considering the role of its potential target in the cariogenic process. The differential expression levels of SpR19 in the strains exposed to both pH5.5 and pH7 culture conditions were verified by quantitative real-time PCR. The expression of the potential target of SpR19, GroEL, was also investigated at both the protein and mRNA level using Western blotting and quantitative real-time PCR. RESULTS Bioinformatic analysis suggested multiple potential target sites of SpR19 both in GroEL mRNA and in the upstream and downstream inter-genic regions. Under different pH conditions, the highly cariogenic strain 17 expressed consistently low levels of SpR19 as compared with the strain 5 with a low cariogenicity; GroEL showed a reverse expression pattern in the 2 strains. An inverse correlation was found between the expressions of SpR19 and GroEL. CONCLUSION The highly cariogenic strain 17 expressed low levels of SpR19 and high levels of GroEL in both acidic and neutral culture conditions. SpR19 may negatively regulate the cariogenicity of Streptococcus mutants by targeting at GroEL.
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Affiliation(s)
- 桐楠 胡
- 解放军总医院口腔科,北京 100853Department of Stomatology, General Hospital of PLA, Beijing 100853, China
| | - 伟 郑
- 军事医学科学院基础医学研究所,北京 100850Institute of Basic Medical Sciences, Academy of Military Medical Sciences, Beijing 100850, China
| | - 少华 李
- 军事医学科学院基础医学研究所,北京 100850Institute of Basic Medical Sciences, Academy of Military Medical Sciences, Beijing 100850, China
| | - 洁 董
- 军事医学科学院基础医学研究所,北京 100850Institute of Basic Medical Sciences, Academy of Military Medical Sciences, Beijing 100850, China
| | - 心玲 王
- 解放军总后勤部第一门诊部口腔中心,北京 100842Center of Stomatology, First Out-patient Clinics, Department of General Logistics of PLA, Beijing 100842, China
| | - 成龙 王
- 解放军总医院口腔科,北京 100853Department of Stomatology, General Hospital of PLA, Beijing 100853, China
| | - 宁生 邵
- 军事医学科学院基础医学研究所,北京 100850Institute of Basic Medical Sciences, Academy of Military Medical Sciences, Beijing 100850, China
| | - 冰峰 储
- 解放军总医院口腔科,北京 100853Department of Stomatology, General Hospital of PLA, Beijing 100853, China
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Mandelli F, Couger MB, Paixão DAA, Machado CB, Carnielli CM, Aricetti JA, Polikarpov I, Prade R, Caldana C, Paes Leme AF, Mercadante AZ, Riaño-Pachón DM, Squina FM. Thermal adaptation strategies of the extremophile bacterium Thermus filiformis based on multi-omics analysis. Extremophiles 2017; 21:775-788. [DOI: 10.1007/s00792-017-0942-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/29/2017] [Indexed: 12/25/2022]
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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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Bacterial community dynamics are linked to patterns of coral heat tolerance. Nat Commun 2017; 8:14213. [PMID: 28186132 PMCID: PMC5309854 DOI: 10.1038/ncomms14213] [Citation(s) in RCA: 282] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 12/02/2016] [Indexed: 02/07/2023] Open
Abstract
Ocean warming threatens corals and the coral reef ecosystem. Nevertheless, corals can be adapted to their thermal environment and inherit heat tolerance across generations. In addition, the diverse microbes that associate with corals have the capacity for more rapid change, potentially aiding the adaptation of long-lived corals. Here, we show that the microbiome of reef corals is different across thermally variable habitats and changes over time when corals are reciprocally transplanted. Exposing these corals to thermal bleaching conditions changes the microbiome for heat-sensitive corals, but not for heat-tolerant corals growing in habitats with natural high heat extremes. Importantly, particular bacterial taxa predict the coral host response in a short-term heat stress experiment. Such associations could result from parallel responses of the coral and the microbial community to living at high natural temperatures. A competing hypothesis is that the microbial community and coral heat tolerance are causally linked. Coral-associated microbes could enhance the capacity of their host organism to respond to environmental change. Ziegler and colleagues use a reciprocal transplant experiment to show that microbiomes of heat-tolerant corals are more resilient to change than those of heat-sensitive corals.
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Gsy, a novel glucansucrase from Leuconostoc mesenteroides, mediates the formation of cell aggregates in response to oxidative stress. Sci Rep 2016; 6:38122. [PMID: 27924943 PMCID: PMC5141493 DOI: 10.1038/srep38122] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 11/07/2016] [Indexed: 12/14/2022] Open
Abstract
Leuconostoc mesenteroides is a member of lactic acid bacteria (LAB) with wide applications in the food and medical industries. Species in the genus Leuconostoc are catalase-negative and generally regarded as facultative anaerobic or aerotolerant organisms. Despite their extensive use in industry, certain issues concerning the aerobic life of L. mesenteroides, e.g., the mechanism involved in the tolerance to oxygen, remain to be addressed. In this manuscript, a survival strategy employed by L. mesenteroides BD3749 in response to oxidative stress was elucidated. BD3749 cells cultivated in medium with sucrose available synthesized large amounts of exopolysaccharides, mostly consisting of insoluble EPS. When BD3749 cells were challenged with oxidative stress, the amount of insoluble EPS was greatly enhanced. The synthesized EPSs reduced the accumulation of reactive oxygen species (ROS) in bacterial cells and improved their survival during chronic oxidative stress. Another study showed that Gsy, a novel glucansucrase in the GH70 family that is induced by sucrose and up-regulated following exposure to oxygen, was responsible for the synthesis of insoluble EPS. Gsy was subsequently demonstrated to play pivotal roles in the formation of aggregates to alleviate the detrimental effects on BD3749 cells exerted by oxygen.
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