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Taylor ZA, Chen P, Noeparvar P, Pham DN, Walker AR, Kitten T, Zeng L. Glycerol metabolism contributes to competition by oral streptococci through production of hydrogen peroxide. J Bacteriol 2024:e0022724. [PMID: 39171915 DOI: 10.1128/jb.00227-24] [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: 06/10/2024] [Accepted: 07/10/2024] [Indexed: 08/23/2024] Open
Abstract
As a biological byproduct from both humans and microbes, glycerol's contribution to microbial homeostasis in the oral cavity remains understudied. In this study, we examined glycerol metabolism by Streptococcus sanguinis, a commensal associated with oral health. Genetic mutants of glucose-PTS enzyme II (manL), glycerol metabolism (glp and dha pathways), and transcriptional regulators were characterized with regard to glycerol catabolism, growth, production of hydrogen peroxide (H2O2), transcription, and competition with Streptococcus mutans. Biochemical assays identified the glp pathway as a novel source for H2O2 production by S. sanguinis that is independent of pyruvate oxidase (SpxB). Genetic analysis indicated that the glp pathway requires glycerol and a transcriptional regulator, GlpR, for expression and is negatively regulated by PTS, but not the catabolite control protein, CcpA. Conversely, deletion of either manL or ccpA increased the expression of spxB and a second, H2O2-non-producing glycerol metabolic pathway (dha), indicative of a mode of regulation consistent with conventional carbon catabolite repression (CCR). In a plate-based antagonism assay and competition assays performed with planktonic and biofilm-grown cells, glycerol greatly benefited the competitive fitness of S. sanguinis against S. mutans. The glp pathway appears to be conserved in several commensal streptococci and actively expressed in caries-free plaque samples. Our study suggests that glycerol metabolism plays a more significant role in the ecology of the oral cavity than previously understood. Commensal streptococci, though not able to use glycerol as a sole carbohydrate source for growth, benefit from the catabolism of glycerol through production of both ATP and H2O2. IMPORTANCE Glycerol is an abundant carbohydrate in the oral cavity. However, little is understood regarding the metabolism of glycerol by commensal streptococci, some of the most abundant oral bacteria. This was in part because most streptococci cannot grow on glycerol as the sole carbon source. In this study, we show that Streptococcus sanguinis, a commensal associated with dental health, can degrade glycerol for persistence and competition through two pathways, one of which generates hydrogen peroxide at levels capable of inhibiting Streptococcus mutans. Preliminary studies suggest that several additional commensal streptococci are also able to catabolize glycerol, and glycerol-related genes are actively expressed in human dental plaque samples. Our findings reveal the potential of glycerol to significantly impact microbial homeostasis, which warrants further exploration.
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Affiliation(s)
- Zachary A Taylor
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Ping Chen
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Payam Noeparvar
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Danniel N Pham
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Alejandro R Walker
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Todd Kitten
- Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Richmond, Virginia, USA
| | - Lin Zeng
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
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Mårli MT, Oppegaard O, Porcellato D, Straume D, Kjos M. Genetic modification of Streptococcus dysgalactiae by natural transformation. mSphere 2024; 9:e0021424. [PMID: 38904369 PMCID: PMC11288034 DOI: 10.1128/msphere.00214-24] [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: 03/18/2024] [Accepted: 05/13/2024] [Indexed: 06/22/2024] Open
Abstract
Streptococcus dysgalactiae is an emerging human and animal pathogen. Functional studies of genes involved in virulence of S. dysgalactiae and other pyogenic group streptococci are often hampered by limited genetic tractability. It is known that pyogenic streptococci carry genes required for competence for natural transformation; however, in contrast to other streptococcal subgroups, there is limited evidence for gene transfer by natural transformation in these bacteria. In this study, we systematically assessed the genomes of 179 S. dysgalactiae strains of both human and animal origins (subsp. equisimilis and dysgalactiae, respectively) for the presence of genes required for natural transformation. While a considerable fraction of the strains contained inactive genes, the majority (64.2%) of the strains had an intact gene set. In selected strains, we examined the dynamics of competence activation after addition of competence-inducing pheromones using transcriptional reporter assays and exploratory RNA-seq. Based on these findings, we were able to establish a protocol allowing us to utilize natural transformation to construct deletion mutants by allelic exchange in several S. dysgalactiae strains of both subspecies. As part of the work, we deleted putative lactose utilization genes to study their role in growth on lactose. The data presented here provide new knowledge on the potential of horizonal gene transfer by natural transformation in S. dysgalactiae and, importantly, demonstrates the possibility to exploit natural transformation for genetic engineering in these bacteria. IMPORTANCE Numerous Streptococcus spp. exchange genes horizontally through natural transformation, which also facilitates efficient genetic engineering in these organisms. However, for the pyogenic group of streptococci, including the emerging pathogen Streptococcus dysgalactiae, there is limited experimental evidence for natural transformation. In this study, we demonstrate that natural transformation in vitro indeed is possible in S. dysgalactiae strains under optimal conditions. We utilized this method to perform gene deletion through allelic exchange in several strains, thereby paving the way for more efficient gene engineering methods in pyogenic streptococci.
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Affiliation(s)
- Marita Torrissen Mårli
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Oddvar Oppegaard
- Haukeland University Hospital, University of Bergen, Bergen, Norway
| | - Davide Porcellato
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Daniel Straume
- 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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Kriswandini IL, Budi HS, Justitia FM. Examination of the Structure and Formation Streptococcus mutans Biofilm Induced by Glucose, Lactose, Soy Protein, and Iron. Eur J Dent 2024; 18:834-840. [PMID: 38555642 PMCID: PMC11290916 DOI: 10.1055/s-0043-1776121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024] Open
Abstract
OBJECTIVE Streptococcus mutans, the main causative agent of caries, have the ability to form biofilms on the surface of teeth. The availability of nutrients such as glucose, lactose, soy protein, and iron can influence S. mutans in biofilm formation. All four sources of nutrients have been shown to increase the formation of S. mutans biofilms. The purpose of this study was to determine the structure and thickness of S. mutans biofilms induced by glucose, lactose, soy protein, and iron. MATERIALS AND METHODS This experimental laboratory study aimed to examine the formation of biofilm structures (chemical elements) and determine the thickness of S. mutans biofilms induced by glucose, lactose, soy protein, and iron. The structures (chemical elements) were examined using scanning electron microscopy-energy-dispersive X-ray (SEM-EDX) analysis. Confocal laser scanning microscopy (CLSM) was used to determine the thickness of S. mutans biofilms with an Olympus FV1000 microscope, and the findings were analyzed using Olympus Fluoview Ver. 4.2a software. RESULTS It was established that the results of SEM-EDX examination of the structure of S. mutans biofilms induced by glucose had oxygen (O) as the dominant chemical element (30.24 w%); lactose reported oxygen (O) as the dominant element (29.65 w%); soy protein had carbon (C) as the dominant element (34.31 w%); and iron showed oxygen (O) as the dominant element (32.51 w%). The thickness (measured by the CLSM examination) of biofilms induced by glucose, lactose, soy protein, and iron were 17,666, 12,666, 18,000, and 15,666 nm, respectively. CONCLUSION The structure of S. mutans biofilms induced by glucose, lactose, and iron contain the following elements in amounts from the highest to lowest: O, C, N, P, and S; the biofilm produced by S. mutans induced by soy protein in amounts from the highest to lowest comprised the elements: C, O, N, S, and P. The S. mutans biofilms induced by soy protein had the maximum thickness, followed by those induced by glucose, iron, and lactose.
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Affiliation(s)
| | - Hendrik Setia Budi
- Department of Oral Biology, Dental Pharmacology, Faculty of Dental Medicine, Universitas Airlangga, Surabaya, Indonesia
| | - Fuadia Mumaiyyiah Justitia
- Department of Oral Biology, Dental Pharmacology, Faculty of Dental Medicine, Universitas Airlangga, Surabaya, Indonesia
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Taylor ZA, Chen P, Noeparvar P, Pham DN, Walker AR, Kitten T, Zeng L. Glycerol Metabolism Contributes to Competition by Oral Streptococci through Production of Hydrogen Peroxide. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.28.598274. [PMID: 38979179 PMCID: PMC11230354 DOI: 10.1101/2024.06.28.598274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
As a biological byproduct from both humans and microbes, glycerol's contribution to microbial homeostasis in the oral cavity remains understudied. Here we examined glycerol metabolism by Streptococcus sanguinis, a commensal associated with oral health. Genetic mutants of glucose-PTS enzyme II ( manL ), glycerol metabolism ( glp and dha pathways), and transcriptional regulators were characterized with regard to glycerol catabolism, growth, production of hydrogen peroxide (H 2 O 2 ), transcription, and competition with Streptococcus mutans . Biochemical assays identified the glp pathway as a novel source of H 2 O 2 production by S. sanguinis that is independent of pyruvate oxidase (SpxB). Genetic analysis indicated that the glp pathway requires glycerol and a transcriptional regulator, GlpR, for expression and is negatively regulated by PTS, but not the catabolite control protein, CcpA. Conversely, deletion of either manL or ccpA increased expression of spxB and a second, H 2 O 2 -non-producing glycerol metabolic pathway ( dha ), indicative of a mode of regulation consistent with conventional carbon catabolite repression (CCR). In a plate-based antagonism assay and competition assays performed with planktonic and biofilm-grown cells, glycerol greatly benefited the competitive fitness of S. sanguinis against S. mutans. The glp pathway appears to be conserved in several commensal streptococci and actively expressed in caries-free plaque samples. Our study suggests that glycerol metabolism plays a more significant role in the ecology of the oral cavity than previously understood. Commensal streptococci, though not able to use glycerol as a sole carbohydrate for growth, benefit from catabolism of glycerol through production of both ATP and H 2 O 2 . Importance Glycerol is an abundant carbohydrate found in oral cavity, both due to biological activities of humans and microbes, and as a common ingredient of foods and health care products. However, very little is understood regarding the metabolism of glycerol by some of the most abundant oral bacteria, commensal streptococci. This was in part because most streptococci cannot grow on glycerol as the sole carbon source. Here we show that Streptococcus sanguinis , an oral commensal associated with dental health, can degrade glycerol for persistence and competition through two independent pathways, one of which generates hydrogen peroxide at levels capable of inhibiting a dental pathobiont, Streptococcus mutans . Preliminary studies suggest that several other commensal streptococci are also able to catabolize glycerol, and glycerol-related genes are being actively expressed in human dental plaque samples. Our findings reveal the potential of glycerol to significantly impact microbial homeostasis which warrants further exploration.
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Choi A, Dong K, Williams E, Pia L, Batagower J, Bending P, Shin I, Peters DI, Kaspar JR. Human Saliva Modifies Growth, Biofilm Architecture and Competitive Behaviors of Oral Streptococci. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.21.554151. [PMID: 37662325 PMCID: PMC10473590 DOI: 10.1101/2023.08.21.554151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
The bacteria within supragingival biofilms participate in complex exchanges with other microbes inhabiting the same niche. One example are the mutans group streptococci (Streptococcus mutans), implicated in the development of tooth decay, and other health-associated commensal streptococci species. Previously, our group transcriptomically characterized intermicrobial interactions between S. mutans and several species of oral bacteria. However, these experiments were carried out in a medium that was absent of human saliva. To better mimic their natural environment, we first evaluated how inclusion of saliva affected growth and biofilm formation of eight streptococci species individually, and found saliva to positively benefit growth rates while negatively influencing biomass accumulation and altering spatial arrangement. These results carried over during evaluation of 29 saliva-derived isolates of various species. Surprisingly, we also found that addition of saliva increased the competitive behaviors of S. mutans in coculture competitions against commensal streptococci that led to increases in biofilm microcolony volumes. Through transcriptomically characterizing mono- and cocultures of S. mutans and Streptococcus oralis with and without saliva, we determined that each species developed a nutritional niche under mixed-species growth, with S. mutans upregulating carbohydrate uptake and utilization pathways while S. oralis upregulated genome features related to peptide uptake and glycan foraging. S. mutans also upregulated genes involved in oxidative stress tolerance, particularly manganese uptake, which we could artificially manipulate by supplementing in manganese to give it an advantage over its opponent. Our report highlights observable changes in microbial behaviors via leveraging environmental- and host-supplied resources over their competitors.
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Affiliation(s)
- Allen Choi
- Division of Biosciences, The Ohio State University College of Dentistry, Columbus, Ohio
| | - Kevin Dong
- Division of Biosciences, The Ohio State University College of Dentistry, Columbus, Ohio
| | - Emily Williams
- Division of Biosciences, The Ohio State University College of Dentistry, Columbus, Ohio
| | - Lindsey Pia
- Division of Biosciences, The Ohio State University College of Dentistry, Columbus, Ohio
| | - Jordan Batagower
- Division of Biosciences, The Ohio State University College of Dentistry, Columbus, Ohio
| | - Paige Bending
- Division of Biosciences, The Ohio State University College of Dentistry, Columbus, Ohio
| | - Iris Shin
- Division of Biosciences, The Ohio State University College of Dentistry, Columbus, Ohio
| | - Daniel I Peters
- Division of Biosciences, The Ohio State University College of Dentistry, Columbus, Ohio
| | - Justin R Kaspar
- Division of Biosciences, The Ohio State University College of Dentistry, Columbus, Ohio
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Nakase Y, Yamaguchi S, Jalkh EBB, Atria PJ, Witek L, Bonfante EA, Li H, Sakai T, Okawa R, Nakano K, Imazato S. In vitro analysis of durability of S-PRG filler-containing composite crowns for primary molar restoration. Dent Mater 2023; 39:640-647. [PMID: 37208292 DOI: 10.1016/j.dental.2023.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 04/25/2023] [Accepted: 04/27/2023] [Indexed: 05/21/2023]
Abstract
OBJECTIVE To evaluate the reliability, maximum principal stress, shear stress, and crack initiation of a computer-aided design/computer-aided manufacturing (CAD/CAM) resin composite (RC) incorporating surface pre-reacted glass (S-PRG) filler for primary molar teeth. METHODS Mandibular primary molar crowns fabricated by experimental (EB) or commercially available CAD/CAM RCs (HC) were prepared and cemented to a resinous abutment tooth using an adhesive resin cement (Cem) or a conventional glass-ionomer cement (CX). These specimens were subjected to a single compressive test (n = 5/each) and the step-stress accelerated life testing (SSALT) (n = 12/each). Data was evaluated using Weibull analyses and reliability was calculated. Afterwards, the maximum principal stress and crack initiation point of each crown was analyzed by finite element analysis. To evaluate bonding of EB and HC to dentin, microtensile bond strength (μTBS) testing was conducted using primary molar teeth (n = 10/each). RESULTS There was no significant difference between the fracture loads of EB and HC for either cement (p > 0.05). The fracture loads of EB-CX and HC-CX were significantly lower than EB-Cem and HC-Cem (p < 0.05). The reliability at 600 N for EB-Cem was greater than that for EB-CX, HC-Cem, and HC-CX. The maximum principal stress concentrated on EB was lower than that on HC. The shear stress concentrated in the cement layer for EB-CX was higher than that for HC-CX. There was no significant difference among the μTBSs of EB-Cem, EB-CX, HC-Cem, and HC-CX (p > 0.05). SIGNIFICANCE The crowns fabricated with the experimental CAD/CAM RC incorporating S-PRG filler yielded greater fracture loads and reliability than the crowns manufactured with commercially available CAD/CAM RC regardless of the luting materials. These findings suggest that the experimental CAD/CAM RC crown may be clinically useful for the restoration of primary molars.
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Affiliation(s)
- Yutaro Nakase
- Department of Dental Biomaterials, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan; Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Satoshi Yamaguchi
- Department of Dental Biomaterials, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Ernesto B Benalcázar Jalkh
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil
| | - Pablo J Atria
- Department of Biomaterials, College of Dentistry, Universidad de los Andes, Santiago, Chile
| | - Lukasz Witek
- Biomaterials Division, NYU College of Dentistry, New York, NY, USA; Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY USA; Hansjörg Wyss Department of Plastic Surgery, New York University Grossman School of Medicine, New York, NY, USA.
| | - Estevam A Bonfante
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil
| | - Hefei Li
- Department of Dental Biomaterials, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takahiko Sakai
- Department of Dental Biomaterials, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan; Department of Fixed Prosthodontics and Orofacial Function, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Rena Okawa
- Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kazuhiko Nakano
- Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Satoshi Imazato
- Department of Dental Biomaterials, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
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Zheng T, Jing M, Gong T, Yan J, Wang X, Xu M, Zhou X, Zeng J, Li Y. Regulatory mechanisms of exopolysaccharide synthesis and biofilm formation in Streptococcus mutans. J Oral Microbiol 2023; 15:2225257. [PMID: 37346997 PMCID: PMC10281425 DOI: 10.1080/20002297.2023.2225257] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 06/07/2023] [Accepted: 06/08/2023] [Indexed: 06/23/2023] Open
Abstract
Background Dental caries is a chronic, multifactorial and biofilm-mediated oral bacterial infection affecting almost every age group and every geographical region. Streptococcus mutans is considered an important pathogen responsible for the initiation and development of dental caries. It produces exopolysaccharides in situ to promote the colonization of cariogenic bacteria and coordinate dental biofilm development. Objective The understanding of the regulatory mechanism of S. mutans biofilm formation can provide a theoretical basis for the prevention and treatment of caries. Design At present, an increasing number of studies have identified many regulatory systems in S. mutans that regulate biofilm formation, including second messengers (e.g. c-di-AMP, Ap4A), transcription factors (e.g. EpsR, RcrR, StsR, AhrC, FruR), two-component systems (e.g. CovR, VicR), small RNA (including sRNA0426, srn92532, and srn133489), acetylation modifications (e.g. ActG), CRISPR-associated proteins (e.g. Cas3), PTS systems (e.g. EIIAB), quorum-sensing signaling system (e.g. LuxS), enzymes (including Dex, YidC, CopZ, EzrA, lmrB, SprV, RecA, PdxR, MurI) and small-molecule metabolites. Results This review summarizes the recent progress in the molecular regulatory mechanisms of exopolysaccharides synthesis and biofilm formation in S. mutans.
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Affiliation(s)
- Ting Zheng
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Meiling Jing
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Tao Gong
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jiangchuan Yan
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xiaowan Wang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Mai Xu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jumei Zeng
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
| | - Yuqing Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Andresen S, de Mojana di Cologna N, Archer-Hartmann S, Rogers AM, Samaddar S, Ganguly T, Black IM, Glushka J, Ng KKS, Azadi P, Lemos JA, Abranches J, Szymanski CM. Involvement of the Streptococcus mutans PgfE and GalE 4-epimerases in protein glycosylation, carbon metabolism, and cell division. Glycobiology 2023; 33:245-259. [PMID: 36637425 PMCID: PMC10114643 DOI: 10.1093/glycob/cwad004] [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: 09/07/2022] [Revised: 01/02/2023] [Accepted: 01/03/2023] [Indexed: 01/14/2023] Open
Abstract
Streptococcus mutans is a key pathogen associated with dental caries and is often implicated in infective endocarditis. This organism forms robust biofilms on tooth surfaces and can use collagen-binding proteins (CBPs) to efficiently colonize collagenous substrates, including dentin and heart valves. One of the best characterized CBPs of S. mutans is Cnm, which contributes to adhesion and invasion of oral epithelial and heart endothelial cells. These virulence properties were subsequently linked to post-translational modification (PTM) of the Cnm threonine-rich repeat region by the Pgf glycosylation machinery, which consists of 4 enzymes: PgfS, PgfM1, PgfE, and PgfM2. Inactivation of the S. mutans pgf genes leads to decreased collagen binding, reduced invasion of human coronary artery endothelial cells, and attenuated virulence in the Galleria mellonella invertebrate model. The present study aimed to better understand Cnm glycosylation and characterize the predicted 4-epimerase, PgfE. Using a truncated Cnm variant containing only 2 threonine-rich repeats, mass spectrometric analysis revealed extensive glycosylation with HexNAc2. Compositional analysis, complemented with lectin blotting, identified the HexNAc2 moieties as GlcNAc and GalNAc. Comparison of PgfE with the other S. mutans 4-epimerase GalE through structural modeling, nuclear magnetic resonance, and capillary electrophoresis demonstrated that GalE is a UDP-Glc-4-epimerase, while PgfE is a GlcNAc-4-epimerase. While PgfE exclusively participates in protein O-glycosylation, we found that GalE affects galactose metabolism and cell division. This study further emphasizes the importance of O-linked protein glycosylation and carbohydrate metabolism in S. mutans and identifies the PTM modifications of the key CBP, Cnm.
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Affiliation(s)
- Silke Andresen
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
- Department of Microbiology and Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | | | | | - Ashley M Rogers
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
- Department of Microbiology and Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Sandip Samaddar
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32603, USA
| | - Tridib Ganguly
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32603, USA
| | - Ian M Black
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - John Glushka
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Kenneth K S Ng
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - José A Lemos
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32603, USA
| | - Jacqueline Abranches
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32603, USA
| | - Christine M Szymanski
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
- Department of Microbiology and Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
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9
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Zeng L, Walker AR, Burne RA, Taylor ZA. Glucose Phosphotransferase System Modulates Pyruvate Metabolism, Bacterial Fitness, and Microbial Ecology in Oral Streptococci. J Bacteriol 2023; 205:e0035222. [PMID: 36468868 PMCID: PMC9879115 DOI: 10.1128/jb.00352-22] [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: 09/20/2022] [Accepted: 11/08/2022] [Indexed: 12/12/2022] Open
Abstract
Spontaneous mutants with defects in the primary glucose phosphotransferase permease (manLMNO) of Streptococcus sanguinis SK36 showed enhanced fitness at low pH. Transcriptomics and metabolomics with a manL deletion mutant (SK36/manL) revealed redirection of pyruvate to production of acetate and formate, rather than lactate. These observations were consistent with measurements of decreased lactic acid accumulation and increased excretion of acetate, formate, pyruvate, and H2O2. Genes showing increased expression in SK36/manL included those encoding carbohydrate transporters, extracellular glycosidases, intracellular polysaccharide metabolism, and arginine deiminase and pathways for metabolism of acetoin, ethanolamine, ascorbate, and formate, along with genes required for membrane biosynthesis and adhesion. Streptococcus mutans UA159 persisted much better in biofilm cocultures with SK36/manL than with SK36, an effect that was further enhanced by culturing the biofilms anaerobically but dampened by adding arginine to the medium. We posited that the enhanced persistence of S. mutans with SK36/manL was in part due to excess excretion of pyruvate by the latter, as addition of pyruvate to S. mutans-S. sanguinis cocultures increased the proportions of UA159 in the biofilms. Reducing the buffer capacity or increasing the concentration of glucose benefited UA159 when cocultured with SK36, but not with SK36/manL, likely due to the altered metabolism and enhanced acid tolerance of the mutant. When manL was deleted in S. mutans or Streptococcus gordonii, the mutants presented altered fitness characteristics. Our study demonstrated that phosphotransferase system (PTS)-dependent modulation of central metabolism can profoundly affect streptococcal fitness and metabolic interactions, revealing another dimension in commensal-pathogen relationships influencing dental caries development. IMPORTANCE Dental caries is underpinned by a dysbiotic microbiome and increased acid production. As beneficial bacteria that can antagonize oral pathobionts, oral streptococci such as S. sanguinis and S. gordonii can ferment many carbohydrates, despite their relative sensitivity to low pH. We characterized the molecular basis for why mutants of glucose transporter ManLMNO of S. sanguinis showed enhanced production of hydrogen peroxide and ammonia and improved persistence under acidic conditions. A metabolic shift involving more than 300 genes required for carbohydrate transport, energy production, and envelope biogenesis was observed. Significantly, manL mutants engineered in three different oral streptococci displayed altered capacities for acid production and interspecies antagonism, highlighting the potential for targeting the glucose-PTS to modulate the pathogenicity of oral biofilms.
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Affiliation(s)
- Lin Zeng
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Alejandro R. Walker
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Robert A. Burne
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Zachary A. Taylor
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
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10
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Li K, Wang J, Du N, Sun Y, Sun Q, Yin W, Li H, Meng L, Liu X. Salivary microbiome and metabolome analysis of severe early childhood caries. BMC Oral Health 2023; 23:30. [PMID: 36658579 PMCID: PMC9850820 DOI: 10.1186/s12903-023-02722-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 01/05/2023] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Severe early childhood caries (SECC) is an inflammatory disease with complex pathology. Although changes in the oral microbiota and metabolic profile of patients with SECC have been identified, the salivary metabolites and the relationship between oral bacteria and biochemical metabolism remains unclear. We aimed to analyse alterations in the salivary microbiome and metabolome of children with SECC as well as their correlations. Accordingly, we aimed to explore potential salivary biomarkers in order to gain further insight into the pathophysiology of dental caries. METHODS We collected 120 saliva samples from 30 children with SECC and 30 children without caries. The microbial community was identified through 16S ribosomal RNA (rRNA) gene high-throughput sequencing. Additionally, we conducted non-targeted metabolomic analysis through ultra-high-performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry to determine the relative metabolite levels and their correlation with the clinical caries status. RESULTS There was a significant between-group difference in 8 phyla and 32 genera in the microbiome. Further, metabolomic and enrichment analyses revealed significantly altered 32 salivary metabolites in children with dental caries, which involved pathways such as amino acid metabolism, pyrimidine metabolism, purine metabolism, ATP-binding cassette transporters, and cyclic adenosine monophosphate signalling pathway. Moreover, four in vivo differential metabolites (2-benzylmalate, epinephrine, 2-formaminobenzoylacetate, and 3-Indoleacrylic acid) might be jointly applied as biomarkers (area under the curve = 0.734). Furthermore, the caries status was correlated with microorganisms and metabolites. Additionally, Spearman's correlation analysis of differential microorganisms and metabolites revealed that Veillonella, Staphylococcus, Neisseria, and Porphyromonas were closely associated with differential metabolites. CONCLUSION This study identified different microbial communities and metabolic profiles in saliva, which may be closely related to caries status. Our findings could inform future strategies for personalized caries prevention, detection, and treatment.
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Affiliation(s)
- Kai Li
- grid.256883.20000 0004 1760 8442Department of Stomatology, Children’s Hospital of Hebei Province, Hebei Medical University, Shijiazhuang, China
| | - Jinmei Wang
- grid.256883.20000 0004 1760 8442Department of Prosthodontics, Hospital of Stomatology Hebei Medical University, Hebei Medical University, Shijiazhuang, China
| | - Ning Du
- grid.256883.20000 0004 1760 8442Department of Stomatology, Children’s Hospital of Hebei Province, Hebei Medical University, Shijiazhuang, China
| | - Yanjie Sun
- grid.256883.20000 0004 1760 8442Department of Stomatology, Children’s Hospital of Hebei Province, Hebei Medical University, Shijiazhuang, China
| | - Qi Sun
- grid.256883.20000 0004 1760 8442Department of Stomatology, Children’s Hospital of Hebei Province, Hebei Medical University, Shijiazhuang, China
| | - Weiwei Yin
- grid.256883.20000 0004 1760 8442Department of Stomatology, Children’s Hospital of Hebei Province, Hebei Medical University, Shijiazhuang, China
| | - Huiying Li
- grid.256883.20000 0004 1760 8442Department of Stomatology, Children’s Hospital of Hebei Province, Hebei Medical University, Shijiazhuang, China
| | - Lingqiang Meng
- grid.256883.20000 0004 1760 8442Department of Prosthodontics, Hospital of Stomatology Hebei Medical University, Hebei Medical University, Shijiazhuang, China
| | - Xuecong Liu
- grid.256883.20000 0004 1760 8442Department of Stomatology, Children’s Hospital of Hebei Province, Hebei Medical University, Shijiazhuang, China
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11
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Sun Y, Chen H, Xu M, He L, Mao H, Yang S, Qiao X, Yang D. Exopolysaccharides metabolism and cariogenesis of Streptococcus mutans biofilm regulated by antisense vicK RNA. J Oral Microbiol 2023; 15:2204250. [PMID: 37138664 PMCID: PMC10150615 DOI: 10.1080/20002297.2023.2204250] [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] [Indexed: 05/05/2023] Open
Abstract
Background Streptococcus mutans (S. mutans) is a pivotal cariogenic pathogen contributing to its multiple virulence factors, one of which is synthesizing exopolysaccharides (EPS). VicK, a sensor histidine kinase, plays a major role in regulating genes associated with EPS synthesis and adhesion. Here we first identified an antisense vicK RNA (ASvicK) bound with vicK into double-stranded RNA (dsRNA). Objective This study aims to investigate the effect and mechanism of ASvicK in the EPS metabolism and cariogenesis of S. mutans. Methods The phenotypes of biofilm were detected by scanning electron microscopy (SEM), gas chromatography-mass spectrometery (GC-MS) , gel permeation chromatography (GPC) , transcriptome analysis and Western blot. Co-immunoprecipitation (Co-ip) assay and enzyme activity experiment were adopted to investigate the mechanism of ASvicK regulation. Caries animal models were developed to study the relationship between ASvicK and cariogenicity of S. mutans. Results Overexpression of ASvicK can inhibit the growth of biofilm, reduce the production of EPS and alter genes and protein related to EPS metabolism. ASvicK can adsorb RNase III to regulate vicK and affect the cariogenicity of S. mutans. Conclusions ASvicK regulates vicK at the transcriptional and post-transcriptional levels, effectively inhibits EPS synthesis and biofilm formation and reduces its cariogenicity in vivo.
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Affiliation(s)
- Yuting Sun
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Hong Chen
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Mengmeng Xu
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Liwen He
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Hongchen Mao
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Shiyao Yang
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Xin Qiao
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Deqin Yang
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
- CONTACT Deqin Yang Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing4404100, China
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12
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Platt MP, Lin YH, Penix T, Wiscovitch-Russo R, Vashee I, Mares CA, Rosch JW, Yu Y, Gonzalez-Juarbe N. A multiomics analysis of direct interkingdom dynamics between influenza A virus and Streptococcus pneumoniae uncovers host-independent changes to bacterial virulence fitness. PLoS Pathog 2022; 18:e1011020. [PMID: 36542660 PMCID: PMC9815659 DOI: 10.1371/journal.ppat.1011020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 01/05/2023] [Accepted: 11/22/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND For almost a century, it has been recognized that influenza A virus (IAV) infection can promote the development of secondary bacterial infections (SBI) mainly caused by Streptococcus pneumoniae (Spn). Recent observations have shown that IAV is able to directly bind to the surface of Spn. To gain a foundational understanding of how direct IAV-Spn interaction alters bacterial biological fitness we employed combinatorial multiomic and molecular approaches. RESULTS Here we show IAV significantly remodels the global transcriptome, proteome and phosphoproteome profiles of Spn independently of host effectors. We identified Spn surface proteins that interact with IAV proteins (hemagglutinin, nucleoprotein, and neuraminidase). In addition, IAV was found to directly modulate expression of Spn virulence determinants such as pneumococcal surface protein A, pneumolysin, and factors associated with antimicrobial resistance among many others. Metabolic pathways were significantly altered leading to changes in Spn growth rate. IAV was also found to drive Spn capsule shedding and the release of pneumococcal surface proteins. Released proteins were found to be involved in evasion of innate immune responses and actively reduced human complement hemolytic and opsonizing activity. IAV also led to phosphorylation changes in Spn proteins associated with metabolism and bacterial virulence. Validation of proteomic data showed significant changes in Spn galactose and glucose metabolism. Furthermore, supplementation with galactose rescued bacterial growth and promoted bacterial invasion, while glucose supplementation led to enhanced pneumolysin production and lung cell apoptosis. CONCLUSIONS Here we demonstrate that IAV can directly modulate Spn biology without the requirement of host effectors and support the notion that inter-kingdom interactions between human viruses and commensal pathobionts can promote bacterial pathogenesis and microbiome dysbiosis.
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Affiliation(s)
- Maryann P. Platt
- Infectious Diseases and Genomic Medicine Group, J Craig Venter Institute, Rockville, Maryland, United States of America
| | - Yi-Han Lin
- Infectious Diseases and Genomic Medicine Group, J Craig Venter Institute, Rockville, Maryland, United States of America
| | - Trevor Penix
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Rosana Wiscovitch-Russo
- Infectious Diseases and Genomic Medicine Group, J Craig Venter Institute, Rockville, Maryland, United States of America
| | - Isha Vashee
- Infectious Diseases and Genomic Medicine Group, J Craig Venter Institute, Rockville, Maryland, United States of America
| | - Chris A. Mares
- Department of Life Sciences, Texas A&M University-San Antonio, Texas, United States of America
| | - Jason W. Rosch
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Yanbao Yu
- Infectious Diseases and Genomic Medicine Group, J Craig Venter Institute, Rockville, Maryland, United States of America
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, United States of America
| | - Norberto Gonzalez-Juarbe
- Infectious Diseases and Genomic Medicine Group, J Craig Venter Institute, Rockville, Maryland, United States of America
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13
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Walker AR, Shields RC. Investigating CRISPR spacer targets and their impact on genomic diversification of Streptococcus mutans. Front Genet 2022; 13:997341. [PMID: 36186424 PMCID: PMC9522601 DOI: 10.3389/fgene.2022.997341] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/17/2022] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas is a bacterial immune system that restricts the acquisition of mobile DNA elements. These systems provide immunity against foreign DNA by encoding CRISPR spacers that help target DNA if it re-enters the cell. In this way, CRISPR spacers are a type of molecular tape recorder of foreign DNA encountered by the host microorganism. Here, we extracted ∼8,000 CRISPR spacers from a collection of over three hundred Streptococcus mutans genomes. Phage DNA is a major target of S. mutans spacers. S. mutans strains have also generated immunity against mobile DNA elements such as plasmids and integrative and conjugative elements. There may also be considerable immunity generated against bacterial DNA, although the relative contribution of self-targeting versus bona fide intra- or inter-species targeting needs to be investigated further. While there was clear evidence that these systems have acquired immunity against foreign DNA, there appeared to be minimal impact on horizontal gene transfer (HGT) constraints on a species-level. There was little or no impact on genome size, GC content and ‘openness’ of the pangenome when comparing between S. mutans strains with low or high CRISPR spacer loads. In summary, while there is evidence of CRISPR spacer acquisition against self and foreign DNA, CRISPR-Cas does not act as a barrier on the expansion of the S. mutans accessory genome.
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Affiliation(s)
- Alejandro R. Walker
- Department of Oral Biology, University of Florida, Gainesville, FL, United States
| | - Robert C. Shields
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR, United States
- *Correspondence: Robert C. Shields,
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14
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Probiotication of Nutritious Fruit and Vegetable Juices: An Alternative to Dairy-Based Probiotic Functional Products. Nutrients 2022; 14:nu14173457. [PMID: 36079714 PMCID: PMC9459872 DOI: 10.3390/nu14173457] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 11/17/2022] Open
Abstract
Fruits and vegetables are widely known to be rich in nutrients, antioxidants, vitamins, dietary fiber, minerals, and a bioactive molecule, making them an essential component of a balanced diet with multiple documented positive effects on human health. The probiotication of plant-based juices for the production of functional and nutraceutical food serves as a healthy alternative to dairy probiotics. They are cholesterol free, lack several dairy allergens, and also encourage ingestion for people with lactose intolerance. This review highlights valuable claims regarding the efficacy of different probiotic strains on various diseases. A comprehensive nutrition comparison and the preference of plant-based over dairy probiotic drinks is also discussed, supported with updated market trends of probiotic drinks (dairy and non-dairy based). An extensive compilation of current plant-based probiotic drinks that are available in markets around the world is listed as a reference. The fermentability of carbon sources by probiotic microorganisms is crucial in addressing the development of plant-based drinks. Therefore, the pathway involved in metabolism of sucrose, glucose, fructose, and galactose in fruit and vegetable juice was also underlined. Finally, the key factors in monitoring the quality of probiotic products such as total soluble solids, sugar consumption, titratable acidity, pH, and stability at low storage temperatures were outlined.
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15
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Deletion of lacD gene affected stress tolerance and virulence of Streptococcus suis serotype 2. J Microbiol 2022; 60:948-959. [DOI: 10.1007/s12275-022-2146-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/27/2022] [Accepted: 06/24/2022] [Indexed: 11/25/2022]
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16
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Biria M, Rezvani Y, Roodgarian R, Rabbani A, Iranparvar P. Antibacterial effect of an herbal toothpaste containing Bamboo salt: a randomized double-blinded controlled clinical trial. BMC Oral Health 2022; 22:193. [PMID: 35590307 PMCID: PMC9121567 DOI: 10.1186/s12903-022-02224-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 04/18/2022] [Indexed: 02/03/2023] Open
Abstract
Background The inclusion of herbal antibacterial agents in the composition of toothpastes is becoming increasingly popular, due to lower side effects. The present study intended to investigate the antibacterial efficacy of a herbal toothpaste containing Bamboo salt on cariogenic oral bacteria. Methods The present double-blinded parallel randomized controlled clinical trial was conducted on 60 dental students (age range: 18–30). Following the baseline saliva sampling, the participants were randomly assigned into the case and control groups, to use the Bamboo salt herbal toothpaste and conventional non-herbal toothpaste, respectively. They were instructed to brush their teeth twice a day using the Bass technique. Saliva sampling was repeated after four weeks. The salivary counts of Streptococcus mutans and Lactobacillus at baseline and 4-week follow-up were determined and presented as the logarithm of colony-forming units per milliliter (log CFU/mL). Results A significant decrease in salivary Streptococcus mutans and Lactobacillus was observed using both toothpastes (*P < 0.001). The difference between the antibacterial efficacy of two toothpaste types on Streptococcus mutans and Lactobacillus was not statistically significant (P = 0.530, and P = 0.137, respectively). Conclusion Due to the comparable efficacy of the investigated herbal toothpaste with conventional toothpaste, it potentially qualifies as a complementary agent for self-care oral hygiene procedures. Trial registration: This trial was registered in the “Iranian Registry of Clinical Trials” (IRCT20210414050964N1) on 21/06/2021. Supplementary Information The online version contains supplementary material available at 10.1186/s12903-022-02224-z.
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Affiliation(s)
- Mina Biria
- Department of Pediatric Dentistry, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Yasaman Rezvani
- Department of Pediatric Dentistry, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Romina Roodgarian
- Department of Pediatric Dentistry, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abbas Rabbani
- Dental Research Center, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Parastoo Iranparvar
- Department of Pediatric Dentistry, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Spontaneous Mutants of Streptococcus sanguinis with Defects in the Glucose-Phosphotransferase System Show Enhanced Post-Exponential-Phase Fitness. J Bacteriol 2021; 203:e0037521. [PMID: 34460310 DOI: 10.1128/jb.00375-21] [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: 02/07/2023] Open
Abstract
Genetic truncations in a gene encoding a putative glucose-phosphotransferase system (PTS) protein (manL, EIIABMan) were identified in subpopulations of two separate laboratory stocks of Streptococcus sanguinis SK36; the mutants had reduced PTS activities on glucose and other monosaccharides. To understand the emergence of these mutants, we engineered deletion mutants of manL and showed that the ManL-deficient strain had improved bacterial viability in the stationary phase and was better able to inhibit the growth of the dental caries pathogen Streptococcus mutans. Transcriptional analysis and biochemical assays suggested that the manL mutant underwent reprograming of central carbon metabolism that directed pyruvate away from production of lactate, increasing production of hydrogen peroxide (H2O2) and excretion of pyruvate. Addition of pyruvate to the medium enhanced the survival of SK36 in overnight cultures. Meanwhile, elevated pyruvate levels were detected in the cultures of a small but significant percentage (∼10%) of clinical isolates of oral commensal bacteria. Furthermore, the manL mutant showed higher expression of the arginine deiminase system than the wild type, which enhanced the ability of the mutant to raise environmental pH when arginine was present. To our surprise, significant discrepancies in genome sequence were identified between strain SK36 obtained from ATCC and the sequence deposited in GenBank. As the conditions that are likely associated with the emergence of spontaneous manL mutations, i.e., excess carbohydrates and low pH, are those associated with caries development, we propose that glucose-PTS strongly influences commensal-pathogen interactions by altering the production of ammonia, pyruvate, and H2O2. IMPORTANCE A health-associated dental microbiome provides a potent defense against pathogens and diseases. Streptococcus sanguinis is an abundant member of a health-associated oral flora that antagonizes pathogens by producing hydrogen peroxide. There is a need for a better understanding of the mechanisms that allow bacteria to survive carbohydrate-rich and acidic environments associated with the development of dental caries. We report the isolation and characterization of spontaneous mutants of S. sanguinis with impairment in glucose transport. The resultant reprograming of the central metabolism in these mutants reduced the production of lactic acid and increased pyruvate accumulation; the latter enables these bacteria to better cope with hydrogen peroxide and low pH. The implications of these discoveries in the development of dental caries are discussed.
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18
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Augustinho do Nascimento C, Kim RR, Ferrari CR, de Souza BM, Braga AS, Magalhães AC. Effect of sweetener containing Stevia on the development of dental caries in enamel and dentin under a microcosm biofilm model. J Dent 2021; 115:103835. [PMID: 34653536 DOI: 10.1016/j.jdent.2021.103835] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE This study compared the effect of commercial and pure sweetener containing stevia to that of aspartame, to sucrose and xylitol on the development of dental caries. METHODS 228 bovine enamel and root dentin were exposed to microcosm biofilm model using human saliva. From the 2nd to the 5th day, the samples were exposed daily to McBain saliva supplemented with 0.2% of the respective sweeteners/sugar, under 5% CO2 and 37 °C. The lactic acid and the colony-forming units (CFU) were quantified. The demineralization was analyzed by TMR. The data were compared statistically (Kruskal-Wallis/ Dunn, p<0.05). RESULTS Pure stevia, pure aspartame, xylitol and control were able to significantly reduce 92% of lactate production compared to sucrose. Stevia finn, aspartame finn and sucrose showed similar production of lactic acid (around 0.45±0.12 g/L and 0.67±0.18 g/L, for enamel and dentin, p<0.0001). With respect to total lactobacilli and S. mutans/S. sobrinus CFU, xylitol and control did not show growth on enamel, while CFU numbers were found in stevia finn, aspartame finn and sucrose groups for both tissues. Enamel and dentin demineralization was significantly reduced for xylitol, control, pure stevia and pure aspartame (85% and 83% reduction, respectively) compared to stevia finn, aspartame finn and sucrose, which in turn did not differ from each other (sucrose ΔZ: 2913.7 ± 646.7 vol%.µm for enamel and 3543.3 ± 432.5 vol%.µm for dentin). CONCLUSIONS Commercial sweeteners containing stevia and aspartame proved to be as cariogenic as sucrose, which may be due to the other components, since the pure forms were not cariogenic. CLINICAL RELEVANCE Our study showed that some commercial sweeteners (aspartame and stevia) are as cariogenic as sucrose, which may be due to the presence of lactose. The population should be advice about the presence of lactose in such brand names, to avoid their consume.
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Affiliation(s)
| | - Rafaela Ricci Kim
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru-SP, Brazil
| | - Carolina Ruis Ferrari
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru-SP, Brazil
| | - Beatriz Martines de Souza
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru-SP, Brazil
| | - Aline Silva Braga
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru-SP, Brazil
| | - Ana Carolina Magalhães
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru-SP, Brazil.
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Nakamya MF, Ayoola MB, Shack LA, Swiatlo E, Nanduri B. The Effect of Impaired Polyamine Transport on Pneumococcal Transcriptome. Pathogens 2021; 10:pathogens10101322. [PMID: 34684271 PMCID: PMC8540371 DOI: 10.3390/pathogens10101322] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/10/2021] [Accepted: 10/12/2021] [Indexed: 12/13/2022] Open
Abstract
Infections due to Streptococcus pneumoniae, a commensal in the nasopharynx, still claim a significant number of lives worldwide. Genome plasticity, antibiotic resistance, and limited serotype coverage of the available polysaccharide-based conjugate vaccines confounds therapeutic interventions to limit the spread of this pathogen. Pathogenic mechanisms that allow successful adaption and persistence in the host could be potential innovative therapeutic targets. Polyamines are ubiquitous polycationic molecules that regulate many cellular processes. We previously reported that deletion of polyamine transport operon potABCD, which encodes a putrescine/spermidine transporter (ΔpotABCD), resulted in an unencapsulated attenuated phenotype. Here, we characterize the transcriptome, metabolome, and stress responses of polyamine transport-deficient S. pneumoniae. Compared with the wild-type strain, the expression of genes involved in oxidative stress responses and the nucleotide sugar metabolism was reduced, while expression of genes involved in the Leloir, tagatose, and pentose phosphate pathways was higher in ΔpotABCD. A metabolic shift towards the pentose phosphate pathway will limit the synthesis of precursors of capsule polysaccharides. Metabolomics results show reduced levels of glutathione and pyruvate in the mutant. Our results also show that the potABCD operon protects pneumococci against hydrogen peroxide and nitrosative stress. Our findings demonstrate the importance of polyamine transport in pneumococcal physiology that could impact in vivo fitness. Thus, polyamine transport in pneumococci represents a novel target for therapeutic interventions.
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Affiliation(s)
- Mary F. Nakamya
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS 39762, USA; (M.F.N.); (M.B.A.); (L.A.S.)
| | - Moses B. Ayoola
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS 39762, USA; (M.F.N.); (M.B.A.); (L.A.S.)
| | - Leslie A. Shack
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS 39762, USA; (M.F.N.); (M.B.A.); (L.A.S.)
| | - Edwin Swiatlo
- Section of Infectious Diseases, Southeast Louisiana Veterans Health Care System, New Orleans, LA 70112, USA;
| | - Bindu Nanduri
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS 39762, USA; (M.F.N.); (M.B.A.); (L.A.S.)
- Correspondence: ; Tel.: +1-662-325-5859; Fax: +1-662-325-1031
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Caudai C, Galizia A, Geraci F, Le Pera L, Morea V, Salerno E, Via A, Colombo T. AI applications in functional genomics. Comput Struct Biotechnol J 2021; 19:5762-5790. [PMID: 34765093 PMCID: PMC8566780 DOI: 10.1016/j.csbj.2021.10.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 10/05/2021] [Accepted: 10/05/2021] [Indexed: 12/13/2022] Open
Abstract
We review the current applications of artificial intelligence (AI) in functional genomics. The recent explosion of AI follows the remarkable achievements made possible by "deep learning", along with a burst of "big data" that can meet its hunger. Biology is about to overthrow astronomy as the paradigmatic representative of big data producer. This has been made possible by huge advancements in the field of high throughput technologies, applied to determine how the individual components of a biological system work together to accomplish different processes. The disciplines contributing to this bulk of data are collectively known as functional genomics. They consist in studies of: i) the information contained in the DNA (genomics); ii) the modifications that DNA can reversibly undergo (epigenomics); iii) the RNA transcripts originated by a genome (transcriptomics); iv) the ensemble of chemical modifications decorating different types of RNA transcripts (epitranscriptomics); v) the products of protein-coding transcripts (proteomics); and vi) the small molecules produced from cell metabolism (metabolomics) present in an organism or system at a given time, in physiological or pathological conditions. After reviewing main applications of AI in functional genomics, we discuss important accompanying issues, including ethical, legal and economic issues and the importance of explainability.
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Affiliation(s)
- Claudia Caudai
- CNR, Institute of Information Science and Technologies “A. Faedo” (ISTI), Pisa, Italy
| | - Antonella Galizia
- CNR, Institute of Applied Mathematics and Information Technologies (IMATI), Genoa, Italy
| | - Filippo Geraci
- CNR, Institute for Informatics and Telematics (IIT), Pisa, Italy
| | - Loredana Le Pera
- CNR, Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Bari, Italy
- CNR, Institute of Molecular Biology and Pathology (IBPM), Rome, Italy
| | - Veronica Morea
- CNR, Institute of Molecular Biology and Pathology (IBPM), Rome, Italy
| | - Emanuele Salerno
- CNR, Institute of Information Science and Technologies “A. Faedo” (ISTI), Pisa, Italy
| | - Allegra Via
- CNR, Institute of Molecular Biology and Pathology (IBPM), Rome, Italy
| | - Teresa Colombo
- CNR, Institute of Molecular Biology and Pathology (IBPM), Rome, Italy
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21
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Ricomini Filho AP, de Assis ACM, Costa Oliveira BE, Cury JA. Cariogenic Potential of Human and Bovine Milk on Enamel Demineralization. Caries Res 2021; 55:260-267. [PMID: 34130289 DOI: 10.1159/000516090] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 03/21/2021] [Indexed: 11/19/2022] Open
Abstract
The higher cariogenicity of human milk when compared with bovine milk is still a debatable subject. Therefore, we evaluated the effect of human or bovine milk exposure on biofilm composition and enamel demineralization using a validated cariogenic biofilm model. Streptococcus mutans UA159 biofilms (n = 8) were grown on human saliva-coated bovine enamel slabs of known surface hardness. The biofilms were exposed 8×/day to 0.9% NaCl (negative control), human milk, bovine milk, 7.0% lactose (active human milk control), 4.5% lactose (active bovine milk control), or 10% sucrose (positive control). The culture medium was changed twice daily, and the pH was analyzed as an indicator of biofilm acidogenicity. After 120 h of growth, biofilms were harvested to evaluate viable cells, and soluble and insoluble extracellular polysaccharides (EPS). Enamel demineralization was assessed by the percentage of surface hardness loss (%SHL). Data were analyzed by one-way ANOVA/Tukey's test (α = 5%). In terms of %SHL, negative control (7.7 ± 3.1), human milk control (13.3 ± 7.5), bovine milk control (15.3 ± 8.2), human milk (7.5 ± 5.0), and bovine milk (8.7 ± 6.3) did not differ among them (p > 0.05) but differed (p < 0.05) from sucrose (55.1 ± 5.4). The findings of enamel demineralization (%SHL) were statistically supported by the data of biofilm acidogenicity, bacterial counts and EPS biofilm composition. This experimental study suggests that human and bovine milk have low cariogenic potential to provoke caries lesions in enamel.
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Affiliation(s)
| | | | - Bárbara E Costa Oliveira
- Piracicaba Dental School, UNICAMP, Piracicaba, Brazil.,Ceuma University, UNICEUMA, São Luís, Brazil
| | - Jaime A Cury
- Piracicaba Dental School, UNICAMP, Piracicaba, Brazil
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22
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Verspecht T, Van Holm W, Boon N, Bernaerts K, Daep CA, Masters JG, Zayed N, Quirynen M, Teughels W. Potential prebiotic substrates modulate composition, metabolism, virulence and inflammatory potential of an in vitro multi-species oral biofilm. J Oral Microbiol 2021; 13:1910462. [PMID: 33968313 PMCID: PMC8079042 DOI: 10.1080/20002297.2021.1910462] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Background: Modulation of the commensal oral microbiota constitutes a promising preventive/therapeutic approach in oral healthcare. The use of prebiotics for maintaining/restoring the health-associated homeostasis of the oral microbiota has become an important research topic. Aims: This study hypothesised that in vitro 14-species oral biofilms can be modulated by (in)direct stimulation of beneficial/commensal bacteria with new potential prebiotic substrates tested at 1 M and 1%(w/v), resulting in more host-compatible biofilms with fewer pathogens, decreased virulence and less inflammatory potential. Methods: Established biofilms were repeatedly rinsed with N-acetyl-D-glucosamine, α-D-lactose, D-(+)-trehalose or D-(+)-raffinose at 1 M or 1%(w/v). Biofilm composition, metabolic profile, virulence and inflammatory potential were eventually determined. Results: Repeated rinsing caused a shift towards a more health-associated microbiological composition, an altered metabolic profile, often downregulated virulence gene expression and decreased the inflammatory potential on oral keratinocytes. At 1 M, the substrates had pronounced effects on all biofilm aspects, whereas at 1%(w/v) they had a pronounced effect on virulence gene expression and a limited effect on inflammatory potential. Conclusion: Overall, this study identified four new potential prebiotic substrates that exhibit different modulatory effects at two different concentrations that cause in vitro multi-species oral biofilms to become more host-compatible.
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Affiliation(s)
- Tim Verspecht
- Department of Oral Health Sciences, University of Leuven (KU Leuven), Leuven, Belgium.,Department of Biotechnology, Center for Microbial Ecology and Technology (CMET), Ghent University (UGent), Gent, Belgium
| | - Wannes Van Holm
- Department of Oral Health Sciences, University of Leuven (KU Leuven), Leuven, Belgium.,Department of Biotechnology, Center for Microbial Ecology and Technology (CMET), Ghent University (UGent), Gent, Belgium
| | - Nico Boon
- Department of Biotechnology, Center for Microbial Ecology and Technology (CMET), Ghent University (UGent), Gent, Belgium
| | - Kristel Bernaerts
- Bio- and Chemical Systems Technology, Reactor Engineering and Safety, Department of Chemical Engineering, University of Leuven (KU Leuven), Leuven Chem & Tech, Leuven, Belgium
| | - Carlo A Daep
- Colgate-Palmolive Technology Center, Piscataway, NJ USA
| | | | - Naiera Zayed
- Department of Oral Health Sciences, University of Leuven (KU Leuven), Leuven, Belgium.,Department of Biotechnology, Center for Microbial Ecology and Technology (CMET), Ghent University (UGent), Gent, Belgium.,Faculty of Pharmacy, Menoufia University, Egypt
| | - Marc Quirynen
- Department of Oral Health Sciences, University of Leuven (KU Leuven), Leuven, Belgium.,Dentistry, University Hospitals Leuven, Leuven, Belgium
| | - Wim Teughels
- Department of Oral Health Sciences, University of Leuven (KU Leuven), Leuven, Belgium.,Dentistry, University Hospitals Leuven, Leuven, Belgium
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23
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Chen J, Zhang A, Xiang Z, Lu M, Huang P, Gong T, Pan Y, Lin Y, Zhou X, Li Y. EpsR Negatively Regulates Streptococcus mutans Exopolysaccharide Synthesis. J Dent Res 2021; 100:968-976. [PMID: 33749354 DOI: 10.1177/00220345211000668] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Streptococcus mutans is considered the primary etiological agent of human dental caries. Glucosyltransferases (Gtfs) from S. mutans play important roles in the formation of biofilm matrix and the development of cariogenic oral biofilm. Therefore, Gtfs are considered an important target to prevent the development of dental caries. However, the role of transcription factors in regulating gtf expression is not yet clear. Here, we identify a MarR (multiple antibiotic resistance regulator) family transcription factor named EpsR (exopolysaccharide synthesis regulator), which negatively regulates gtfB expression and exopolysaccharide (EPS) production in S. mutans. The epsR in-frame deletion strain grew slowly, aggregated more easily in the presence of dextran, and displayed different colony morphology and biofilm structure. Notably, epsR deletion resulted in altered 3-dimensional biofilm architecture, increased water-insoluble EPS production, and upregulated GtfB protein content and activity. In addition, global gene expression profiling revealed differences in the expression levels of 69 genes in which gtfB was markedly upregulated. The conserved DNA motif for EpsR binding was determined by electrophoretic mobility shift assay and DNase I footprinting assays. Moreover, analysis of β-galactosidase activity suggested that EpsR acted as a repressor and inhibited gtfB expression. Taken together, our findings indicate that EpsR is an important transcription factor that regulates gtfB expression and EPS production in S. mutans. These results add new aspects to the complexity of regulating the expression of genes involved in the cariogenicity of S. mutans, which might lead to novel strategies to prevent the formation of cariogenic biofilm that may favor diseases.
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Affiliation(s)
- J Chen
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - A Zhang
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Z Xiang
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - M Lu
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - P Huang
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - T Gong
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Y Pan
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Y Lin
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - X Zhou
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Y Li
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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24
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Site-Specific Mutations of GalR Affect Galactose Metabolism in Streptococcus pneumoniae. J Bacteriol 2020; 203:JB.00180-20. [PMID: 33046563 DOI: 10.1128/jb.00180-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 10/02/2020] [Indexed: 12/11/2022] Open
Abstract
Streptococcus pneumoniae (the pneumococcus) is a formidable human pathogen that is capable of asymptomatically colonizing the nasopharynx. Progression from colonization to invasive disease involves adaptation to distinct host niches, which vary markedly in the availability of key nutrients such as sugars. We previously reported that cell-cell signaling via the autoinducer 2 (AI-2)/LuxS quorum-sensing system boosts the capacity of S. pneumoniae to utilize galactose as a carbon source by upregulation of the Leloir pathway. This resulted in increased capsular polysaccharide production and a hypervirulent phenotype. We hypothesized that this effect was mediated by phosphorylation of GalR, the transcriptional activator of the Leloir pathway. GalR is known to possess three putative phosphorylation sites, S317, T319, and T323. In the present study, derivatives of S. pneumoniae D39 with putative phosphorylation-blocking alanine substitution mutations at each of these GalR sites (singly or in combination) were constructed. Growth assays and transcriptional analyses revealed complex phenotypes for these GalR mutants, with impacts on the regulation of both the Leloir and tagatose 6-phosphate pathways. The alanine substitution mutations significantly reduced the capacity of pneumococci to colonize the nasopharynx, middle ear, and lungs in a murine intranasal challenge model.IMPORTANCE Pneumococcal survival in the host and capacity to transition from a commensal to a pathogenic lifestyle are closely linked to the organism's ability to utilize specific nutrients in distinct niches. Galactose is a major carbon source for pneumococci in the upper respiratory tract. We have shown that both the Leloir and tagatose 6-phosphate pathways are necessary for pneumococcal growth in galactose and demonstrated GalR-mediated interplay between the two pathways. Moreover, the three putative phosphorylation sites in the transcriptional regulator GalR play a critical role in galactose metabolism and are important for pneumococcal colonization of the nasopharynx, middle ear, and lungs.
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25
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Salli K, Söderling E, Hirvonen J, Gürsoy UK, Ouwehand AC. Influence of 2'-fucosyllactose and galacto-oligosaccharides on the growth and adhesion of Streptococcus mutans. Br J Nutr 2020; 124:824-831. [PMID: 32498722 PMCID: PMC7525117 DOI: 10.1017/s0007114520001956] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 05/05/2020] [Accepted: 05/27/2020] [Indexed: 01/15/2023]
Abstract
Human milk oligosaccharides, such as 2'-fucosyllactose (2'-FL), and galacto-oligosaccharides (GOS), a prebiotic carbohydrate mixture, are being increasingly added to infant formulas, necessitating the understanding of their impact on the oral microbiota. Here, for the first time, the effects of 2'-FL and GOS on the planktonic growth and adhesion characteristics of the caries-associated oral pathogen Streptococcus mutans were assessed, and the results were compared against the effects of xylitol, lactose and glucose. There were differences in S. mutans growth between 2'-FL and GOS. None of the three S. mutans strains grew with 2'-FL, while they all grew with GOS as well as lactose and glucose. Xylitol inhibited S. mutans growth. The adhesion of S. mutans CI 2366 to saliva-coated hydroxyapatite was reduced by 2'-FL and GOS. Exopolysaccharide-mediated adhesion of S. mutans DSM 20523 to a glass surface was decreased with 2'-FL, GOS and lactose, and the adhesion of strain CI 2366 strain was reduced only by GOS. Unlike GOS, 2'-FL did not support the growth of any S. mutans strain. Neither 2'-FL nor GOS enhanced the adhesive properties of the S. mutans strains, but they inhibited some of the tested strains. Thus, the cariogenic tendency may vary between infant formulas containing different types of oligosaccharides.
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Affiliation(s)
- K. Salli
- DuPont Nutrition & Biosciences, Kantvik, Finland
- Faculty of Medicine, Institute of Dentistry, University of Turku, Turku, Finland
| | - E. Söderling
- Faculty of Medicine, Institute of Dentistry, University of Turku, Turku, Finland
| | - J. Hirvonen
- DuPont Nutrition & Biosciences, Kantvik, Finland
| | - U. K. Gürsoy
- Faculty of Medicine, Institute of Dentistry, University of Turku, Turku, Finland
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26
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Zeng L, Burne RA. Subpopulation behaviors in lactose metabolism by Streptococcus mutans. Mol Microbiol 2020; 115:58-69. [PMID: 32881164 DOI: 10.1111/mmi.14596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/17/2020] [Accepted: 08/24/2020] [Indexed: 01/08/2023]
Abstract
When Streptococcus mutans is transferred from a preferred carbohydrate (glucose or fructose) to lactose, initiation of growth can take several hours, and substantial amounts of glucose are released during growth. Here, S. mutans strains UA159 and GS-5 were examined for stochastic behaviors in transcription of the lac operon. Using a gfp reporter fusion, we demonstrated that induction of the lac operon occurs in only a fraction of the population, with prior exposure to carbohydrate source and strain influencing the magniture of the sub-population response. Lower glucokinase activity in GS-5 was associated with release of substantially more glucose than UA159 and significantly lower lac expression. Mutants unable to use lactose grew on lactose as the sole carbohydrate when strains with an intact lac operon were also present in the cultures, indicative of the potential for population cheating. Utilizing a set of engineered obligate cheating and non-cheating strains, we confirmed that cheating can sustain a heterogeneous population. Futher, obligate cheaters of GS-5 competed well with the non-cheaters and showed a high degree of competitive fitness in a human-derived consortium biofilm model. The results show that bet-hedging behaviors in carbohydrate metabolism may substantially influence the composition and pathogenic potential of oral biofilms.
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Affiliation(s)
- Lin Zeng
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Robert A Burne
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
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27
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Zeng L, Burne RA. Molecular mechanisms controlling fructose-specific memory and catabolite repression in lactose metabolism by Streptococcus mutans. Mol Microbiol 2020; 115:70-83. [PMID: 32881130 DOI: 10.1111/mmi.14597] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/17/2020] [Accepted: 08/24/2020] [Indexed: 01/26/2023]
Abstract
Lactose is an abundant dietary carbohydrate metabolized by the dental pathogen Streptococcus mutans. Lactose metabolism presents both classic diauxic behaviors and long-term memory, where the bacteria can pause for >11 h before initiating growth on lactose. Here, we explored mechanisms contributing to unusual aspects of regulation of the lac operon. The fructose-phosphate metabolites, F-1-P and F-6-P, could modulate the DNA-binding activities of the lactose repressor. Recombinant LacR proteins bound upstream of lacA and Gal-6-P induced the formation of different LacR-DNA complexes. Deletion of lacR resulted in strain-specific growth phenotypes on lactose, but also on a number of mono- and di-saccharides that involve the glucose-PTS or glucokinase in their catabolism. The phenotypes were consistent with the novel findings that loss of LacR altered glucose-PTS activity and expression of the gene for glucokinase. CcpA was also shown to affect lactose metabolism in vivo and to bind to the lacA promoter region in vitro. Collectively, our study reveals complex molecular circuits controlling lactose metabolism in S. mutans, where LacR and CcpA integrate cellular and environmental cues to regulate metabolism of a variety of carbohydrates that are critical to persistence and pathogenicity of S. mutans.
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Affiliation(s)
- Lin Zeng
- 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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28
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Eida AA, Bougouffa S, L’Haridon F, Alam I, Weisskopf L, Bajic VB, Saad MM, Hirt H. Genome Insights of the Plant-Growth Promoting Bacterium Cronobacter muytjensii JZ38 With Volatile-Mediated Antagonistic Activity Against Phytophthora infestans. Front Microbiol 2020; 11:369. [PMID: 32218777 PMCID: PMC7078163 DOI: 10.3389/fmicb.2020.00369] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 02/19/2020] [Indexed: 12/12/2022] Open
Abstract
Salinity stress is a major challenge to agricultural productivity and global food security in light of a dramatic increase of human population and climate change. Plant growth promoting bacteria can be used as an additional solution to traditional crop breeding and genetic engineering. In the present work, the induction of plant salt tolerance by the desert plant endophyte Cronobacter sp. JZ38 was examined on the model plant Arabidopsis thaliana using different inoculation methods. JZ38 promoted plant growth under salinity stress via contact and emission of volatile compounds. Based on the 16S rRNA and whole genome phylogenetic analysis, fatty acid analysis and phenotypic identification, JZ38 was identified as Cronobacter muytjensii and clearly separated and differentiated from the pathogenic C. sakazakii. Full genome sequencing showed that JZ38 is composed of one chromosome and two plasmids. Bioinformatic analysis and bioassays revealed that JZ38 can grow under a range of abiotic stresses. JZ38 interaction with plants is correlated with an extensive set of genes involved in chemotaxis and motility. The presence of genes for plant nutrient acquisition and phytohormone production could explain the ability of JZ38 to colonize plants and sustain plant growth under stress conditions. Gas chromatography-mass spectrometry analysis of volatiles produced by JZ38 revealed the emission of indole and different sulfur volatile compounds that may play a role in contactless plant growth promotion and antagonistic activity against pathogenic microbes. Indeed, JZ38 was able to inhibit the growth of two strains of the phytopathogenic oomycete Phytophthora infestans via volatile emission. Genetic, transcriptomic and metabolomics analyses, combined with more in vitro assays will provide a better understanding the highlighted genes' involvement in JZ38's functional potential and its interaction with plants. Nevertheless, these results provide insight into the bioactivity of C. muytjensii JZ38 as a multi-stress tolerance promoting bacterium with a potential use in agriculture.
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Affiliation(s)
- Abdul Aziz Eida
- DARWIN21, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Salim Bougouffa
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- BioScience Core Lab, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | | | - Intikhab Alam
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Laure Weisskopf
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Vladimir B. Bajic
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Maged M. Saad
- DARWIN21, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Heribert Hirt
- DARWIN21, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
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29
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Duanis-Assaf D, Kenan E, Sionov R, Steinberg D, Shemesh M. Proteolytic Activity of Bacillus subtilis upon κ-Casein Undermines Its "Caries-Safe" Effect. Microorganisms 2020; 8:microorganisms8020221. [PMID: 32041335 PMCID: PMC7074799 DOI: 10.3390/microorganisms8020221] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 01/28/2020] [Accepted: 02/04/2020] [Indexed: 02/06/2023] Open
Abstract
Milk is believed to be a relatively “caries-safe” food. This belief relies on the fact that caseins, which constitute around 80% of milk’s protein content, were found to inhibit the adhesion of Streptococcus mutans to enamel and, therefore, decrease biofilm formation. While S. mutans is considered a leading cause of dental disorders, Bacillus subtilis is a non-pathogenic foodborne bacterium, frequently contaminating milk and its products. This study aimed to investigate the effects of dairy-associated foodborne bacteria such as B. subtilis on biofilm formation by S. mutans in the presence of casein proteins. Our results indicate that there is a significant decrease in total biofilm formation by S. mutans exposed to a casein protein mixture in a mono-species culture, whereas, in the co-culture with B. subtilis, an inhibitory effect of the caseins mixture on S. mutans biofilm formation was observed. Proteolytic activity analysis suggested that B. subtilis is capable of breaking down milk proteins, especially κ-casein, which enables biofilm formation by S. mutans in the presence of milk caseins. Therefore, these findings may challenge the assumption that milk is “caries-safe”, especially in a complex microbial environment.
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Affiliation(s)
- Danielle Duanis-Assaf
- Department of Food Sciences, Institute for Postharvest Technology and Food Sciences, Agricultural Research Organization (ARO), Volcani Center, Rishon LeZion 7505101, Israel;
- Biofilm Research Laboratory, Institute of Dental Sciences, Faculty of Dental Medicine, Hebrew University-Hadassah, Jerusalem 9112001, Israel; (E.K.); (R.S.); (D.S.)
| | - Eli Kenan
- Biofilm Research Laboratory, Institute of Dental Sciences, Faculty of Dental Medicine, Hebrew University-Hadassah, Jerusalem 9112001, Israel; (E.K.); (R.S.); (D.S.)
| | - Ronit Sionov
- Biofilm Research Laboratory, Institute of Dental Sciences, Faculty of Dental Medicine, Hebrew University-Hadassah, Jerusalem 9112001, Israel; (E.K.); (R.S.); (D.S.)
| | - Doron Steinberg
- Biofilm Research Laboratory, Institute of Dental Sciences, Faculty of Dental Medicine, Hebrew University-Hadassah, Jerusalem 9112001, Israel; (E.K.); (R.S.); (D.S.)
| | - Moshe Shemesh
- Department of Food Sciences, Institute for Postharvest Technology and Food Sciences, Agricultural Research Organization (ARO), Volcani Center, Rishon LeZion 7505101, Israel;
- Correspondence: ; Tel.: +972-3-968-3868
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30
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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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31
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Deng J, Gu L, Chen T, Huang H, Yin X, Lv X, Liu Y, Li N, Liu Z, Li J, Du G, Liu L. Engineering the Substrate Transport and Cofactor Regeneration Systems for Enhancing 2'-Fucosyllactose Synthesis in Bacillus subtilis. ACS Synth Biol 2019; 8:2418-2427. [PMID: 31550146 DOI: 10.1021/acssynbio.9b00314] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Human milk oligosaccharides (HMOs) have been proven to be beneficial to infants' intestinal health and immune systems. 2'-Fucosyllactose (2'-FL) is the most abundant and thoroughly studied HMO and has been approved to be an additive of infant formula. How to construct efficient and safe microbial cell factories for the production of 2'-FL attracts increasing attention. In this work, we engineered the Bacillus subtilis as an efficient 2'-FL producer by engineering the substrate transport and cofactor guanosine 5'-triphosphate (GTP) regeneration systems. First, we constructed a synthesis pathway for the 2'-FL precursor guanosine 5'-diphosphate-l-fucose (GDP-l-fucose) by introducing the salvage pathway gene fkp from Bacteriodes fragilis and improved the fucose importation by overexpressing the transporters. Then, the complete synthesis pathway of 2'-FL was constructed by introducing the heterologous fucosyltransferases from different sources, and it was found that the gene from Helicobacter pylori was the best one for 2'-FL synthesis. We also improved the substrate lactose importation by introducing heterologous lactose permeases and eliminated endogenous β-galactosidase (yesZ) to block the lactose degradation. Next, the production of 2'-FL and GDP-l-fucose was improved by fine-tuning the expression of cofactor guanosine 5'-triphosphate regeneration module genes gmd, ndk, guaA, guaC, ykfN, deoD, and xpt. Finally, a 3 L fed-batch fermentation was performed, and the highest 2'-FL titer reached 5.01 g/L with a yield up to 0.85 mol/mol fucose. We optimized the synthesis modules of 2'-FL in B. subtilis, and this provides a good starting point for metabolic engineering to further improve 2'-FL production in the future.
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Affiliation(s)
- Jieying Deng
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Liuyan Gu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Taichi Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Hao Huang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xiaoqiang Yin
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xueqin Lv
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Yanfeng Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Nan Li
- State Key Laboratory of Dairy Biotechnology, Shanghai Engineering Research Center of Dairy Biotechnology, Dairy Research Institute, Bright Dairy & Food Co, Ltd., Shanghai 200436, China
| | - Zhenmin Liu
- State Key Laboratory of Dairy Biotechnology, Shanghai Engineering Research Center of Dairy Biotechnology, Dairy Research Institute, Bright Dairy & Food Co, Ltd., Shanghai 200436, China
| | - Jianghua Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Guocheng Du
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Long Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
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Iskandar CF, Cailliez-Grimal C, Borges F, Revol-Junelles AM. Review of lactose and galactose metabolism in Lactic Acid Bacteria dedicated to expert genomic annotation. Trends Food Sci Technol 2019. [DOI: 10.1016/j.tifs.2019.03.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Meng Y, Wu T, Billings R, Kopycka-Kedzierawski DT, Xiao J. Human genes influence the interaction between Streptococcus mutans and host caries susceptibility: a genome-wide association study in children with primary dentition. Int J Oral Sci 2019; 11:19. [PMID: 31148553 PMCID: PMC6544625 DOI: 10.1038/s41368-019-0051-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 02/20/2019] [Accepted: 04/16/2019] [Indexed: 01/16/2023] Open
Abstract
Streptococcus mutans is a well-known cause of dental caries, due to its acidogenicity, aciduricity, and ability to synthesize exopolysaccharides in dental plaques. Intriguingly, not all children who carry S. mutans manifest caries, even with similar characteristics in oral hygiene, diet, and other environmental factors. This phenomenon suggests that host susceptibility potentially plays a role in the development of dental caries; however, the association between host genetics, S. mutans, and dental caries remains unclear. Therefore, this study examined the influence of host gene-by-S. mutans interaction on dental caries. Genome-wide association analyses were conducted in 709 US children (<13 years old), using the dbGap database acquired from the center for oral health research in appalachia (COHRA) and the Iowa Head Start programmes (GEIRS). A generalized estimating equation was used to examine the gene-by-S. mutans interaction effects on the outcomes (decayed and missing/filled primary teeth due to caries). Sequentially, the COHRA and GEIRS data were used to identify potential interactions and replicate the findings. Three loci at the genes interleukin 32 (IL32), galactokinase 2 (GALK2), and CUGBP, Elav-like family member 4 (CELF4) were linked to S. mutans carriage, and there was a severity of caries at a suggestive significance level among COHRA children (P < 9 × 10-5), and at a nominal significance level among GEIRS children (P = 0.047-0.001). The genetic risk score that combined the three loci also significantly interacted with S. mutans (P < 0.000 1). Functional analyses indicated that the identified genes are involved in the host immune response, galactose carbohydrate metabolism, and food-rewarding system, which could potentially be used to identify children at high risk for caries and to develop personalized caries prevention strategies.
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Affiliation(s)
- Ying Meng
- School of Nursing, University of Rochester, Rochester, NY, USA
| | - Tongtong Wu
- Department of Biostatistics and Computational Biology, University of Rochester, Rochester, NY, USA
| | - Ronald Billings
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, NY, USA
| | | | - Jin Xiao
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, NY, USA.
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Galactose Impacts the Size and Intracellular Composition of the Asaccharolytic Oral Pathobiont Porphyromonas gingivalis. Appl Environ Microbiol 2019; 85:AEM.02268-18. [PMID: 30552185 DOI: 10.1128/aem.02268-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 12/04/2018] [Indexed: 11/20/2022] Open
Abstract
The asaccharolytic anaerobe Porphyromonas gingivalis metabolizes proteins it encounters in the periodontal pocket, including host-derived glycoproteins such as mucins and immunoglobulins. Often, these proteins are protected by a diverse array of carbohydrates tethered to the polypeptide chain via glycolytic bonds, and P. gingivalis produces enzymes capable of liberating these carbohydrates, exposing the proteinaceous core. In this study, we investigated the effect of individual monosaccharides, including galactose, l-fucose, mannose, and glucose, on the growth and physiology of P. gingivalis Of the carbohydrates tested, only galactose noticeably altered the density of the bacterial culture, and we observed that cultures grown with galactose reached significantly higher densities during stationary phase. Importantly, electron micrographs and plating of P. gingivalis in stationary phase demonstrated that the presence of galactose did not increase cell numbers; instead, the higher densities resulted from the expansion of individual cells which contained large intracellular granules. Initial attempts to characterize these granules revealed only a subtle increase in soluble carbohydrates, suggesting they are likely not composed of stored carbohydrate. Also, an analysis of major surface polysaccharides via an enzyme-linked immunosorbent assay (ELISA) did not reveal significant differences between cells grown with or without galactose. Finally, an initial investigation of the transcriptional changes elicited by galactose in late exponential phase suggested that genes important for cell shape and for the general stress response may play roles in this phenomenon. Overall, galactose, a monosaccharide commonly present on the surfaces of host proteins, substantially alters the physiology of P. gingivalis via the production of large, currently undefined, intracellular granules.IMPORTANCE Environmental perturbations are central to the ability of pathobionts, such as Porphyromonas gingivalis, to promote the development of diseased sites. In the case of periodontal disease, increased local pH, a shift to anaerobic surroundings, and the accumulation of Gram-negative anaerobes at the expense of Gram-positive cocci are known ecological fluctuations prominently associated with progression toward disease. Importantly, in contrast, the alterations to subgingival food webs in disease sites remain poorly characterized. We hypothesized that given the dramatic shift in community structure during disease, it is possible that free carbohydrates, which would typically be readily metabolized by Gram-positive cocci after cleavage from glycoproteins, may increase in concentration locally and thereby affect the physiological state of the subgingival microbiota. In this study, we explored the impact of free monosaccharides on P. gingivalis to gain deeper insight into the effect of dysbiotic conditions on the growth and physiology of this periodontal pathogen.
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Zeng L, Burne RA. Essential Roles of the sppRA Fructose-Phosphate Phosphohydrolase Operon in Carbohydrate Metabolism and Virulence Expression by Streptococcus mutans. J Bacteriol 2019; 201:e00586-18. [PMID: 30348833 PMCID: PMC6304665 DOI: 10.1128/jb.00586-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 10/16/2018] [Indexed: 11/20/2022] Open
Abstract
The dental caries pathogen Streptococcus mutans can ferment a variety of sugars to produce organic acids. Exposure of S. mutans to certain nonmetabolizable carbohydrates, such as xylitol, impairs growth and can cause cell death. Recently, the presence of a sugar-phosphate stress in S. mutans was demonstrated using a mutant lacking 1-phosphofructokinase (FruK) that accumulates fructose-1-phosphate (F-1-P). Here, we studied an operon in S. mutans, sppRA, which was highly expressed in the fruK mutant. Biochemical characterization of a recombinant SppA protein indicated that it possessed hexose-phosphate phosphohydrolase activity, with preferences for F-1-P and, to a lesser degree, fructose-6-phosphate (F-6-P). SppA activity was stimulated by Mg2+ and Mn2+ but inhibited by NaF. SppR, a DeoR family regulator, repressed the expression of the sppRA operon to minimum levels in the absence of the fructose-derived metabolite F-1-P and likely also F-6-P. The accumulation of F-1-P, as a result of growth on fructose, not only induced sppA expression, but it significantly altered biofilm maturation through increased cell lysis and enhanced extracellular DNA release. Constitutive expression of sppA, via a plasmid or by deleting sppR, greatly alleviated fructose-induced stress in a fruK mutant, enhanced resistance to xylitol, and reversed the effects of fructose on biofilm formation. Finally, by identifying three additional putative phosphatases that are capable of promoting sugar-phosphate tolerance, we show that S. mutans is capable of mounting a sugar-phosphate stress response by modulating the levels of certain glycolytic intermediates, functions that are interconnected with the ability of the organism to manifest key virulence behaviors.IMPORTANCEStreptococcus mutans is a major etiologic agent for dental caries, primarily due to its ability to form biofilms on the tooth surface and to convert carbohydrates into organic acids. We have discovered a two-gene operon in S. mutans that regulates fructose metabolism by controlling the levels of fructose-1-phosphate, a potential signaling compound that affects bacterial behaviors. With fructose becoming increasingly common and abundant in the human diet, we reveal the ways that fructose may alter bacterial development, stress tolerance, and microbial ecology in the oral cavity to promote oral diseases.
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Affiliation(s)
- Lin Zeng
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Robert A Burne
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
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Shi Y, Li R, White DJ, Biesbrock AR. Stannous Fluoride Effects on Gene Expression of Streptococcus mutans and Actinomyces viscosus. Adv Dent Res 2018; 29:124-130. [PMID: 29355427 DOI: 10.1177/0022034517737027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A genome-wide transcriptional analysis was performed to elucidate the bacterial cellular response of Streptococcus mutans and Actinomyces viscosus to NaF and SnF2. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of SnF2 were predetermined before microarray study. Gene expression profiling microarray experiments were carried out in the absence (control) and presence (experimental) of 10 ppm and 100 ppm Sn2+ (in the form of SnF2) and fluoride controls for 10-min exposures (4 biological replicates/treatment). These Sn2+ levels and treatment time were chosen because they have been shown to slow bacterial growth of S. mutans (10 ppm) and A. viscosus (100 ppm) without affecting cell viability. All data generated by microarray experiments were analyzed with bioinformatics tools by applying the following criteria: 1) a q value should be ≤0.05, and 2) an absolute fold change in transcript level should be ≥1.5. Microarray results showed SnF2 significantly inhibited several genes encoding enzymes of the galactose pathway upon a 10-min exposure versus a negative control: lacA and lacB (A and B subunits of the galactose-6-P isomerase), lacC (tagatose-6-P kinase), lacD (tagatose-1,6-bP adolase), galK (galactokinase), galT (galactose-1-phosphate uridylyltransferase), and galE (UDP-glucose 4-epimerase). A gene fruK encoding fructose-1-phosphate kinase in the fructose pathway was also significantly inhibited. Several genes encoding fructose/mannose-specific enzyme IIABC components in the phosphotransferase system (PTS) were also downregulated, as was ldh encoding lactate dehydrogenase, a key enzyme involved in lactic acid synthesis. SnF2 downregulated the transcription of most key enzyme genes involved in the galactose pathway and also suppressed several key genes involved in the PTS, which transports sugars into the cell in the first step of glycolysis.
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Affiliation(s)
- Y Shi
- 1 The Procter and Gamble Company, Beijing Technical Center, Beijing, China
| | - R Li
- 2 The Procter and Gamble Company, International Operations SA SG Branch, Singapore
| | - D J White
- 3 The Procter and Gamble Company, Mason Business Center, Mason, OH, USA
| | - A R Biesbrock
- 3 The Procter and Gamble Company, Mason Business Center, Mason, OH, USA
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Pan Y, An H, Fu T, Zhao S, Zhang C, Xiao G, Zhang J, Zhao X, Hu G. Characterization of Streptococcus pluranimalium from a cattle with mastitis by whole genome sequencing and functional validation. BMC Microbiol 2018; 18:182. [PMID: 30419812 PMCID: PMC6233522 DOI: 10.1186/s12866-018-1327-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 10/29/2018] [Indexed: 11/17/2022] Open
Abstract
Background Streptococcus pluranimalium is a new member of the Streptococcus genus isolated from multiple different animal hosts. It has been identified as a pathogen associated with subclinical mastitis, valvular endocarditis and septicaemia in animals. Moreover, this bacterium has emerged as a new pathogen for human infective endocarditis and brain abscess. However, the patho-biological properties of S. pluranimalium remain virtually unknown. The aim of this study was to determine the complete genome sequence of S. pluranimalium strain TH11417 isolated from a cattle with mastitis, and to characterize its antimicrobial resistance, virulence, and carbon catabolism. Results The genome of S. pluranimalium TH11417, determined by single-molecule real-time (SMRT) sequencing, consists of 2,065,522 base pair (bp) with a G + C content of 38.65%, 2,007 predicted coding sequence (CDS), 58 transfer RNA (tRNA) genes and five ribosome RNA (rRNA) operons. It contains a novel ISSpl1 element (a memeber of the IS3 family) and a Ф11417.1 prophage that carries the mef(A), msr(D) and lnu(C) genes. Consistently, our antimicrobial susceptibility test confirmed that S. pluranimalium TH11417 was resistant to erythromycin and lincomycin. However, this strain did not show virulence in murine pneumonia (intranasal inoculation, 107 colony forming unit – CFU) and sepsis (intraperitoneal inoculation, 107 CFU) models. Additionally, this strain is able to grow with glucose, lactose or galactose as the sole carbon source, and possesses a lactose-specific phosphoenolpyruvate-dependent phosphotransferase system (PTS). Conclusions We reported the first whole genome sequence of S. pluranimalium isolated from a cattle with mastitis. It harbors a prophage carrying the mef(A), msr(D) and lnu(C) genes, and is avirulent in the murine infection model.
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Affiliation(s)
- Yushan Pan
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, China. .,Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China.
| | - Haoran An
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China.,Tsinghua-Peking Joint Center for Life Science, School of Medicine, Tsinghua University, Beijing, China
| | - Tong Fu
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Shiyu Zhao
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Chengwang Zhang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Genhui Xiao
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Jingren Zhang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Xinfang Zhao
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Gongzheng Hu
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, China.
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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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Solopova A, Bachmann H, Teusink B, Kok J, Kuipers OP. Further Elucidation of Galactose Utilization in Lactococcus lactis MG1363. Front Microbiol 2018; 9:1803. [PMID: 30123211 PMCID: PMC6085457 DOI: 10.3389/fmicb.2018.01803] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/17/2018] [Indexed: 11/20/2022] Open
Abstract
Since the 1970s, galactose metabolism in Lactococcus lactis has been in debate. Different studies led to diverse outcomes making it difficult to conclude whether galactose uptake was PEP- or ATP- dependent and decide what the exact connection was between galactose and lactose uptake and metabolism. It was shown that some Lactococcus strains possess two galactose-specific systems – a permease and a PTS, even if they lack the lactose utilization plasmid, proving that a lactose-independent PTSGal exists. However, the PTSGal transporter was never identified. Here, with the help of transcriptome analyses and genetic knock-out mutants, we reveal the identities of two low-affinity galactose PTSs. A novel plant-niche-related PTS component Llmg_0963 forming a hybrid transporter Llmg_0963PtcBA and a glucose/mannose-specific PTS are shown to be involved in galactose transport in L. lactis MG1363.
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Affiliation(s)
- Ana Solopova
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Herwig Bachmann
- Faculty of Earth and Life Sciences, Systems Bioinformatics IBIVU/NISB, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Bas Teusink
- Faculty of Earth and Life Sciences, Systems Bioinformatics IBIVU/NISB, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Jan Kok
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
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Leonard A, Gierok P, Methling K, Gómez-Mejia A, Hammerschmidt S, Lalk M. Metabolic inventory of Streptococcus pneumoniae growing in a chemical defined environment. Int J Med Microbiol 2018; 308:705-712. [DOI: 10.1016/j.ijmm.2018.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 12/22/2017] [Accepted: 01/02/2018] [Indexed: 11/24/2022] Open
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Zeng L, Chen L, Burne RA. Preferred Hexoses Influence Long-Term Memory in and Induction of Lactose Catabolism by Streptococcus mutans. Appl Environ Microbiol 2018; 84:e00864-18. [PMID: 29752268 PMCID: PMC6029091 DOI: 10.1128/aem.00864-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 04/29/2018] [Indexed: 02/05/2023] Open
Abstract
Bacteria prioritize sugar metabolism via carbohydrate catabolite repression, which regulates global gene expression to optimize the catabolism of preferred substrates. Here, we report an unusual long-term memory effect in certain Streptococcus mutans strains that alters adaptation to growth on lactose after prior exposure to glucose or fructose. In strain GS-5, cells that were first cultured on fructose and then transferred to lactose displayed an exceptionally long lag (>11 h) and slower growth compared to cells first cultured on glucose or cellobiose, which displayed a reduction in lag phase by as much as 10 h. When grown on lactose, mutants lacking the cellobiose-phosphotransferase (PTS) or phospho-β-glucosidase lost the accelerated growth associated with prior culturing on glucose. The memory effects of glucose or fructose on lactose catabolism were not as profound in strain UA159, but the lag phase was considerably shorter in mutants lacking the glucose-PTS EIIMan Interestingly, when S. mutans was cultivated on lactose, significant quantities of free glucose accumulated in the medium, with higher levels found in the cultures of strains lacking EIIMan, glucokinase, or both. Free glucose was also detected in cultures that were utilizing cellobiose or trehalose, albeit at lower levels. Such release of hexoses by S. mutans is likely of biological significance as it was found that cells required small amounts of glucose or other preferred carbohydrates to initiate efficient growth on lactose. These findings suggest that S. mutans modulates the induction of lactose utilization based on its prior exposure to glucose or fructose, which can be liberated from common disaccharides.IMPORTANCE Understanding the molecular mechanisms employed by oral bacteria to control sugar metabolism is key to developing novel therapies for management of dental caries and other oral diseases. Lactose is a naturally occurring disaccharide that is abundant in dairy products and commonly ingested by humans. However, for the dental caries pathogen Streptococcus mutans, relatively little is known about the molecular mechanisms that regulate expression of genes required for lactose uptake and catabolism. Two peculiarities of lactose utilization by S. mutans are explored here: (i) S. mutans excretes glucose that it cleaves from lactose, and (ii) prior exposure to certain carbohydrates can result in a long-term inability to use lactose. The study begins to shed light on how S. mutans may utilize bet hedging to optimize its persistence and virulence in the human oral cavity.
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Affiliation(s)
- Lin Zeng
- Department of Oral Biology, University of Florida, College of Dentistry, Gainesville, Florida, USA
| | - Lulu Chen
- Department of Oral Biology, University of Florida, College of Dentistry, Gainesville, Florida, USA
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Robert A Burne
- Department of Oral Biology, University of Florida, College of Dentistry, Gainesville, Florida, USA
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He Q, Hou Q, Wang Y, Li J, Li W, Kwok LY, Sun Z, Zhang H, Zhong Z. Comparative genomic analysis of Enterococcus faecalis: insights into their environmental adaptations. BMC Genomics 2018; 19:527. [PMID: 29996769 PMCID: PMC6042284 DOI: 10.1186/s12864-018-4887-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 06/19/2018] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Enterococcus faecalis is widely studied as a common gut commensal and a nosocomial pathogen. In fact, Enterococcus faecalis is ubiquitous in nature, and it has been isolated from various niches, including the gastrointestinal tract, faeces, blood, urine, water, and fermented foods (such as dairy products). In order to elucidate the role of habitat in shaping the genome of Enterococcus faecalis, we performed a comparative genomic analysis of 78 strains of various origins. RESULTS Although no correlation was found between the strain isolation habitat and the phylogeny of Enterococcus faecalis from our whole genome-based phylogenetic analysis, our results revealed some environment-associated features in the analysed Enterococcus faecalis genomes. Significant differences were found in the genome size and the number of predicted open reading frames (ORFs) between strains originated from different environments. In general, strains from water sources had the smallest genome size and the least number of predicted ORFs. We also identified 293 environment-specific genes, some of which might link to the adaptive strategies for survival in particular environments. In addition, the number of antibiotic resistance genes was significantly different between strains isolated from dairy products, water, and blood. Strains isolated from blood had the largest number of antibiotic resistance genes. CONCLUSION These findings improve our understanding of the role of habitat in shaping the genomes of Enterococcus faecalis.
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Affiliation(s)
- Qiuwen He
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education P.R. C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China.,Key Laboratory of Dairy Products Processing, Ministry of Agriculture P.R.C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China
| | - Qiangchuan Hou
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education P.R. C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China.,Key Laboratory of Dairy Products Processing, Ministry of Agriculture P.R.C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China
| | - Yanjie Wang
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education P.R. C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China.,Key Laboratory of Dairy Products Processing, Ministry of Agriculture P.R.C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China
| | - Jing Li
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education P.R. C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China.,Key Laboratory of Dairy Products Processing, Ministry of Agriculture P.R.C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China
| | - Weicheng Li
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education P.R. C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China.,Key Laboratory of Dairy Products Processing, Ministry of Agriculture P.R.C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China
| | - Lai-Yu Kwok
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education P.R. C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China.,Key Laboratory of Dairy Products Processing, Ministry of Agriculture P.R.C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China
| | - Zhihong Sun
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education P.R. C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China.,Key Laboratory of Dairy Products Processing, Ministry of Agriculture P.R.C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China
| | - Heping Zhang
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education P.R. C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China.,Key Laboratory of Dairy Products Processing, Ministry of Agriculture P.R.C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China
| | - Zhi Zhong
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education P.R. C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China. .,Key Laboratory of Dairy Products Processing, Ministry of Agriculture P.R.C, Inner Mongolia Agricultural University, Huhhot, 010018, People's Republic of China.
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43
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Nomura R, Morita Y, Matayoshi S, Nakano K. Inhibitory effect of surface pre-reacted glass-ionomer (S-PRG) eluate against adhesion and colonization by Streptococcus mutans. Sci Rep 2018; 8:5056. [PMID: 29568011 PMCID: PMC5864963 DOI: 10.1038/s41598-018-23354-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 03/08/2018] [Indexed: 12/17/2022] Open
Abstract
Surface Pre-reacted Glass-ionomer (S-PRG) filler is a bioactive filler produced by PRG technology, which has been applied to various dental materials. A S-PRG filler can release multiple ions from a glass-ionomer phase formed in the filler. In the present study, detailed inhibitory effects induced by S-PRG eluate (prepared with S-PRG filler) against Streptococcus mutans, a major pathogen of dental caries, were investigated. S-PRG eluate effectively inhibited S. mutans growth especially in the bacterium before the logarithmic growth phase. Microarray analysis was performed to identify changes in S. mutans gene expression in the presence of the S-PRG eluate. The S-PRG eluate prominently downregulated operons related to S. mutans sugar metabolism, such as the pdh operon encoding the pyruvate dehydrogenase complex and the glg operon encoding a putative glycogen synthase. The S-PRG eluate inhibited several in vitro properties of S. mutans relative to the development of dental caries especially prior to active growth. These results suggest that the S-PRG eluate may effectively inhibit the bacterial growth of S. mutans following downregulation of operons involved in sugar metabolism resulting in attenuation of the cariogenicity of S. mutans, especially before the active growth phase.
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Affiliation(s)
- Ryota Nomura
- Department of Pediatric Dentistry, Division of Oral Infections and Disease Control, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan.
| | - Yumiko Morita
- Department of Pediatric Dentistry, Division of Oral Infections and Disease Control, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
| | - Saaya Matayoshi
- Department of Pediatric Dentistry, Division of Oral Infections and Disease Control, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
| | - Kazuhiko Nakano
- Department of Pediatric Dentistry, Division of Oral Infections and Disease Control, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
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44
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Coupling Fluxes, Enzymes, and Regulation in Genome-Scale Metabolic Models. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2017; 1716:337-351. [PMID: 29222761 DOI: 10.1007/978-1-4939-7528-0_15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Genome-scale models have expanded beyond their metabolic origins. Multiple modeling frameworks are required to combine metabolism with enzymatic networks, transcription, translation, and regulation. Mathematical programming offers a powerful set of tools for tackling these "multi-modality" models, although special attention must be paid to the connections between modeling types. This chapter reviews common methods for combining metabolic and discrete logical models into a single mathematical programming framework. Best practices, caveats, and recommendations are presented for the most commonly used software packages. Methods for troubleshooting large sets of logical rules are also discussed.
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45
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Coordinated Regulation of the EII Man and fruRKI Operons of Streptococcus mutans by Global and Fructose-Specific Pathways. Appl Environ Microbiol 2017; 83:AEM.01403-17. [PMID: 28821551 DOI: 10.1128/aem.01403-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 08/15/2017] [Indexed: 11/20/2022] Open
Abstract
The glucose/mannose-phosphotransferase system (PTS) permease EIIMan encoded by manLMN in the dental caries pathogen Streptococcus mutans has a dominant influence on sugar-specific, CcpA-independent catabolite repression (CR). Mutations in manL affect energy metabolism and virulence-associated traits, including biofilm formation, acid tolerance, and competence. Using promoter::reporter fusions, expression of the manLMN and the fruRKI operons, encoding a transcriptional regulator, a fructose-1-phosphate kinase and a fructose-PTS permease EIIFru, respectively, was monitored in response to carbohydrate source and in mutants lacking CcpA, FruR, and components of EIIMan Expression of genes for EIIMan and EIIFru was directly regulated by CcpA and CR, as evinced by in vivo and in vitro methods. Unexpectedly, not only was the fruRKI operon negatively regulated by FruR, but also so was manLMN Carbohydrate transport by EIIMan had a negative influence on expression of manLMN but not fruRKI In agreement with the proposed role of FruR in regulating these PTS operons, loss of fruR or fruK substantially altered growth on a number of carbohydrates, including fructose. RNA deep sequencing revealed profound changes in gene regulation caused by deletion of fruK or fruR Collectively, these findings demonstrate intimate interconnection of the regulation of two major PTS permeases in S. mutans and reveal novel and important contributions of fructose metabolism to global regulation of gene expression.IMPORTANCE The ability of Streptococcus mutans and other streptococcal pathogens to survive and cause human diseases is directly dependent upon their capacity to metabolize a variety of carbohydrates, including glucose and fructose. Our research reveals that metabolism of fructose has broad influences on the regulation of utilization of glucose and other sugars, and mutants with changes in certain genes involved in fructose metabolism display profoundly different abilities to grow and express virulence-related traits. Mutants lacking the FruR regulator or a particular phosphofructokinase, FruK, display changes in expression of a large number of genes encoding transcriptional regulators, enzymes required for energy metabolism, biofilm development, biosynthetic and degradative processes, and tolerance of a spectrum of environmental stressors. Since fructose is a major component of the modern human diet, the results have substantial significance in the context of oral health and the development of dental caries.
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46
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Ravcheev DA, Thiele I. Comparative Genomic Analysis of the Human Gut Microbiome Reveals a Broad Distribution of Metabolic Pathways for the Degradation of Host-Synthetized Mucin Glycans and Utilization of Mucin-Derived Monosaccharides. Front Genet 2017; 8:111. [PMID: 28912798 PMCID: PMC5583593 DOI: 10.3389/fgene.2017.00111] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 08/11/2017] [Indexed: 12/27/2022] Open
Abstract
The colonic mucus layer is a dynamic and complex structure formed by secreted and transmembrane mucins, which are high-molecular-weight and heavily glycosylated proteins. Colonic mucus consists of a loose outer layer and a dense epithelium-attached layer. The outer layer is inhabited by various representatives of the human gut microbiota (HGM). Glycans of the colonic mucus can be used by the HGM as a source of carbon and energy when dietary fibers are not sufficiently available. Both commensals and pathogens can utilize mucin glycans. Commensals are mostly involved in the cleavage of glycans, while pathogens mostly utilize monosaccharides released by commensals. This HGM-derived degradation of the mucus layer increases pathogen susceptibility and causes many other health disorders. Here, we analyzed 397 individual HGM genomes to identify pathways for the cleavage of host-synthetized mucin glycans to monosaccharides as well as for the catabolism of the derived monosaccharides. Our key results are as follows: (i) Genes for the cleavage of mucin glycans were found in 86% of the analyzed genomes, which significantly higher than a previous estimation. (ii) Genes for the catabolism of derived monosaccharides were found in 89% of the analyzed genomes. (iii) Comparative genomic analysis identified four alternative forms of the monosaccharide-catabolizing enzymes and four alternative forms of monosaccharide transporters. (iv) Eighty-five percent of the analyzed genomes may be involved in potential feeding pathways for the monosaccharides derived from cleaved mucin glycans. (v) The analyzed genomes demonstrated different abilities to degrade known mucin glycans. Generally, the ability to degrade at least one type of mucin glycan was predicted for 81% of the analyzed genomes. (vi) Eighty-two percent of the analyzed genomes can form mutualistic pairs that are able to degrade mucin glycans and are not degradable by any of the paired organisms alone. Taken together, these findings provide further insight into the inter-microbial communications of the HGM as well as into host-HGM interactions.
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Affiliation(s)
- Dmitry A Ravcheev
- Luxembourg Centre for Systems Biomedicine, University of LuxembourgEsch-sur-Alzette, Luxembourg
| | - Ines Thiele
- Luxembourg Centre for Systems Biomedicine, University of LuxembourgEsch-sur-Alzette, Luxembourg
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47
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Ackerman DL, Doster RS, Weitkamp JH, Aronoff DM, Gaddy JA, Townsend SD. Human Milk Oligosaccharides Exhibit Antimicrobial and Antibiofilm Properties against Group B Streptococcus. ACS Infect Dis 2017; 3:595-605. [PMID: 28570820 PMCID: PMC5868341 DOI: 10.1021/acsinfecdis.7b00064] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Streptococcus agalactiae (Group B Streptococcus, GBS) is a Gram-positive bacterial pathogen that causes invasive infections in both children and adults. During pregnancy, GBS is a significant cause of infection of the fetal membranes (chorioamnionitis), which can lead to intra-amniotic infection, preterm birth, stillbirth, and neonatal sepsis. Recently, breastfeeding has been thought to represent a potential mode of GBS transmission from mother to newborn, which might increase the risk for late-onset sepsis. Little is known, however, about the molecular components of breast milk that may support or prevent GBS colonization. In this study, we examine how human milk oligosaccharides (HMOs) affect the pathogenesis of GBS. HMOs from discrete donor samples were isolated and profiled by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). Growth and biofilm assays show that HMOs from mothers of specific milk groups can modulate the growth and biofilm formation of GBS. High-resolution field-emission gun scanning electron microscopy (SEM) and confocal laser scanning microscopy confirmed the quantitative biofilm assays and demonstrated cell arrangement perturbations in bacterial cultures treated with specific oligosaccharides. These findings demonstrate that HMOs affect the growth and cell biology of GBS. Finally, this study provides the first example of HMOs functioning as antibiofilm agents against GBS.
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Affiliation(s)
- Dorothy L. Ackerman
- Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, Nashville, TN 37235
| | - Ryan S. Doster
- Department of Medicine, Vanderbilt University Medical Center, 1161 21st Avenue South D-3100 Medical Center North, Nashville, TN 37232
| | - Jörn-Hendrik Weitkamp
- Department of Medicine, Vanderbilt University Medical Center, 1161 21st Avenue South D-3100 Medical Center North, Nashville, TN 37232
- Department of Pediatrics, Monroe Carell Jr. Children’s Hospital at Vanderbilt, 2200 Children’s Way, Suite 2404, Nashville, TN 37232
| | - David M. Aronoff
- Department of Medicine, Vanderbilt University Medical Center, 1161 21st Avenue South D-3100 Medical Center North, Nashville, TN 37232
| | - Jennifer A. Gaddy
- Department of Medicine, Vanderbilt University Medical Center, 1161 21st Avenue South D-3100 Medical Center North, Nashville, TN 37232
- Tennessee Valley Healthcare Systems, Department of Veterans Affairs, 1310 24th Avenue South, Nashville, TN 37212
| | - Steven D. Townsend
- Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, Nashville, TN 37235
- Institute of Chemical Biology, Vanderbilt University, 896 Preston Research Building, Nashville, TN 37232-6304
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48
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He J, Kim D, Zhou X, Ahn SJ, Burne RA, Richards VP, Koo H. RNA-Seq Reveals Enhanced Sugar Metabolism in Streptococcus mutans Co-cultured with Candida albicans within Mixed-Species Biofilms. Front Microbiol 2017. [PMID: 28642749 PMCID: PMC5462986 DOI: 10.3389/fmicb.2017.01036] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Early childhood caries (ECC), which can lead to rampant tooth-decay that is painful and costly to treat, is one of the most prevalent infectious diseases affecting children worldwide. Previous studies support that interactions between Streptococcus mutans and Candida albicans are associated with the pathogenesis of ECC. The presence of Candida enhances S. mutans growth, fitness and accumulation within biofilms in vitro, although the molecular basis for these behaviors is undefined. Using an established co-cultivation biofilm model and RNA-Seq, we investigated how C. albicans influences the transcriptome of S. mutans. The presence of C. albicans dramatically altered gene expression in S. mutans in the dual-species biofilm, resulting in 393 genes differentially expressed, compared to mono-species biofilms of S. mutans. By Gene Ontology analysis, the majority of up-regulated genes were related to carbohydrate transport and metabolic/catabolic processes. KEGG pathway impact analysis showed elevated pyruvate and galactose metabolism, suggesting that co-cultivation with C. albicans influences carbohydrate utilization by S. mutans. Analysis of metabolites confirmed the increases in carbohydrate metabolism, with elevated amounts of formate in the culture medium of co-cultured biofilms. Moreover, co-cultivation with C. albicans altered transcription of S. mutans signal transduction (comC and ciaRH) genes associated with fitness and virulence. Interestingly, the expression of genes for mutacins (bacteriocins) and CRISPR were down-regulated. Collectively, the data provide a comprehensive insight into S. mutans transcriptomic changes induced by C. albicans, and offer novel insights into how bacterial–fungal interactions may enhance the severity of dental caries.
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Affiliation(s)
- Jinzhi He
- State Key Laboratory of Oral Diseases, Department of Endodontics, West China Hospital of Stomatology, Sichuan UniversityChengdu, China.,Biofilm Research Labs, Levy Center for Oral Health, Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, PhiladelphiaPA, United States
| | - Dongyeop Kim
- Biofilm Research Labs, Levy Center for Oral Health, Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, PhiladelphiaPA, United States
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, Department of Endodontics, West China Hospital of Stomatology, Sichuan UniversityChengdu, China
| | - Sang-Joon Ahn
- Department of Oral Biology, College of Dentistry, University of Florida, GainesvilleFL, United States
| | - Robert A Burne
- Department of Oral Biology, College of Dentistry, University of Florida, GainesvilleFL, United States
| | - Vincent P Richards
- Department of Biological Sciences, Clemson University, ClemsonSC, United States
| | - Hyun Koo
- Biofilm Research Labs, Levy Center for Oral Health, Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, PhiladelphiaPA, United States
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49
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Marsh PD, Do T, Beighton D, Devine DA. Influence of saliva on the oral microbiota. Periodontol 2000 2017; 70:80-92. [PMID: 26662484 DOI: 10.1111/prd.12098] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2015] [Indexed: 11/28/2022]
Abstract
Saliva plays a major role in determining the composition and activity of the oral microbiota, via a variety of mechanisms. Molecules, mainly from saliva, form a conditioning film on oral surfaces, thus providing receptors for bacterial attachment. The attached cells use saliva components, such as glycoproteins, as their main source of nutrients for growth. Oral bacteria work sequentially and in a concerted manner to catabolize these structurally complex molecules. Saliva also buffers the pH in the biofilm to around neutrality, creating an environment which is conducive to the growth of many oral bacteria that provide important benefits to the host. Components of the adaptive and innate host defences are delivered by saliva, and these often function synergistically, and at sublethal concentrations, so a complex relationship develops between the host and the resident microbiota. Dysbiosis can occur rapidly if the flow of saliva is perturbed.
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50
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Genes associated to lactose metabolism illustrate the high diversity of Carnobacterium maltaromaticum. Food Microbiol 2016; 58:79-86. [PMID: 27217362 DOI: 10.1016/j.fm.2016.03.008] [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: 07/25/2015] [Revised: 03/02/2016] [Accepted: 03/11/2016] [Indexed: 11/20/2022]
Abstract
The dairy population of Carnobacterium maltaromaticum is characterized by a high diversity suggesting a high diversity of the genetic traits linked to the dairy process. As lactose is the main carbon source in milk, the genetics of lactose metabolism was investigated in this LAB. Comparative genomic analysis revealed that the species C. maltaromaticum exhibits genes related to the Leloir and the tagatose-6-phosphate (Tagatose-6P) pathways. More precisely, strains can bear genes related to one or both pathways and several strains apparently do not contain homologs related to these pathways. Analysis at the population scale revealed that the Tagatose-6P and the Leloir encoding genes are disseminated in multiple phylogenetic lineages of C. maltaromaticum: genes of the Tagatose-6P pathway are present in the lineages I, II and III, and genes of the Leloir pathway are present in the lineages I, III and IV. These data suggest that these genes evolved thanks to horizontal transfer, genetic duplication and translocation. We hypothesize that the lac and gal genes evolved in C. maltaromaticum according to a complex scenario that mirrors the high population diversity.
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