1
|
Merritt J, Kreth J. Illuminating the oral microbiome and its host interactions: tools and approaches for molecular microbiology studies. FEMS Microbiol Rev 2023; 47:fuac050. [PMID: 36549660 PMCID: PMC10719069 DOI: 10.1093/femsre/fuac050] [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: 08/18/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Advancements in DNA sequencing technologies within the last decade have stimulated an unprecedented interest in the human microbiome, largely due the broad diversity of human diseases found to correlate with microbiome dysbiosis. As a direct consequence of these studies, a vast number of understudied and uncharacterized microbes have been identified as potential drivers of mucosal health and disease. The looming challenge in the field is to transition these observations into defined molecular mechanistic studies of symbiosis and dysbiosis. In order to meet this challenge, many of these newly identified microbes will need to be adapted for use in experimental models. Consequently, this review presents a comprehensive overview of the molecular microbiology tools and techniques that have played crucial roles in genetic studies of the bacteria found within the human oral microbiota. Here, we will use specific examples from the oral microbiome literature to illustrate the biology supporting these techniques, why they are needed in the field, and how such technologies have been implemented. It is hoped that this information can serve as a useful reference guide to help catalyze molecular microbiology studies of the many new understudied and uncharacterized species identified at different mucosal sites in the body.
Collapse
Affiliation(s)
- Justin Merritt
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, United States
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, United States
| | - Jens Kreth
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, United States
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, United States
| |
Collapse
|
2
|
Yu J, Wang Y, Han D, Cao W, Zheng L, Xie Z, Liu H. Identification of Streptococcus mutans genes involved in fluoride resistance by screening of a transposon mutant library. Mol Oral Microbiol 2020; 35:260-270. [PMID: 33000897 DOI: 10.1111/omi.12316] [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: 06/04/2020] [Revised: 09/18/2020] [Accepted: 09/23/2020] [Indexed: 11/28/2022]
Abstract
Fluoride has been used as an effective anticaries agent for more than 70 years, which might result in the emergence of fluoride-resistant strains. However, the fluoride resistance mechanism and the cariogenic properties of fluoride-resistant mutant for cariogenic bacterial species Streptococcus mutans remain largely unknown. We describe here the construction and characterization of a mariner-based transposon system designed to be used in S. mutans, which is also potentially applicable to other streptococci. To identify genetic determinants of fluoride resistance in S. mutans, we constructed a library of S. mutans transposon insertion mutants and screened this library to identify mutants exhibiting fluoride resistance phenotype. Two mutants were found to carry transposon insertion in two different genetic loci (smu.396 and smu.1291c), respectively. Our subsequent genetic study indicates the fluoride-resistant phenotype for the mutant with the insertion in smu.1291c is resulting from the constitutive overexpression of downstream operon smu.1290c-89c, which is consistent with the previous reports. We also demonstrate for the first time that the deletion of smu.396 is responsible for the fluoride-resistant phenotype and that the combining of smu1290c-89c overexpression and smu.396 deletion in one strain could attribute an additive effect on the fluoride resistance. In addition, our results suggest that the biological fitness of those fluoride-resistant mutants is reduced compared to that of wild-type strain. Overall, our identification and characterization of genetic determinants responsible for fluoride resistance in S. mutans expand our understanding of the fluoride resistance mechanism and the biological consequence of the fluoride resistance strains.
Collapse
Affiliation(s)
- Jie Yu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China
| | - Yaqi Wang
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China
| | - Dongmei Han
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China
| | - Wei Cao
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China
| | - Lanyan Zheng
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Zhoujie Xie
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China
| | - Hao Liu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China
| |
Collapse
|
3
|
Nilsson M, Givskov M, Twetman S, Tolker-Nielsen T. Inactivation of the pgmA Gene in Streptococcus mutans Significantly Decreases Biofilm-Associated Antimicrobial Tolerance. Microorganisms 2019; 7:microorganisms7090310. [PMID: 31484288 PMCID: PMC6780209 DOI: 10.3390/microorganisms7090310] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 08/29/2019] [Accepted: 08/30/2019] [Indexed: 11/16/2022] Open
Abstract
Screening of a Streptococcus mutans mutant library indicated that pgmA mutants displayed a reduced biofilm-associated tolerance toward gentamicin. The biofilms formed by the S. mutanspgmA mutant also displayed decreased tolerance towards linezolid and vancomycin compared to wild-type biofilms. On the contrary, the resistance of planktonic S. mutanspgmA cells to gentamycin, linezolid, and vancomycin was more similar to wild-type levels. Investigations of biofilms grown in microtiter trays and on submerged glass slides showed that pgmA mutants formed roughly the same amount of biofilm as the wild type, indicating that the reduced antimicrobial tolerance of these mutants is not due to diminished biofilm formation. The pgmA gene product is known to be involved in the synthesis of precursors for cell wall components such as teichoic acids and membrane glycolipids. Accordingly, the S. mutanspgmA mutant showed increased sensitivity to Congo Red, indicating that it has impaired cell wall integrity. A changed cell wall composition of the S. mutanspgmA mutant may play a role in the increased sensitivity of S. mutanspgmA biofilms toward antibiotics.
Collapse
Affiliation(s)
- Martin Nilsson
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Michael Givskov
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore
| | - Svante Twetman
- Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| |
Collapse
|
4
|
Nilsson M, Jakobsen TH, Givskov M, Twetman S, Tolker-Nielsen T. Oxidative stress response plays a role in antibiotic tolerance of Streptococcus mutans biofilms. MICROBIOLOGY-SGM 2019; 165:334-342. [PMID: 30663959 DOI: 10.1099/mic.0.000773] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Knowledge about biofilm-associated antibiotic tolerance mechanisms is warranted in order to develop effective treatments against biofilm infections. We performed a screen of a Streptococcus mutans transposon mutant library for mutants with reduced biofilm-associated antimicrobial tolerance, and found that the spxA1 gene plays a role in tolerance towards gentamicin and other antibiotics such as vancomycin and linezolid. SpxA1 is a regulator of genes involved in the oxidative stress response in S. mutans. The oxidative stress response genes gor and ahpC were found to be up-regulated upon antibiotic treatment of S. mutans wild-type biofilms, but not spxA1 mutant biofilms. The gor gene product catalyses the formation of glutathione which functions as an important antioxidant during oxidative stress, and accordingly biofilm-associated antibiotic tolerance of the spxA1 mutant could be restored by exogenous addition of glutathione. Our results indicate that the oxidative stress response plays a role in biofilm-associated antibiotic tolerance of S. mutans, and add to the on-going debate on the role of reactive oxygen species in antibiotic mediated killing of bacteria.
Collapse
Affiliation(s)
- Martin Nilsson
- 1Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tim Holm Jakobsen
- 1Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael Givskov
- 1Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- 2Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Svante Twetman
- 3Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tim Tolker-Nielsen
- 1Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
5
|
Abstract
Mutant libraries, generated by transposons and screened for various phenotypes, have led to many important discoveries regarding gene functions in various organisms. In this chapter we describe the use of plasmid pMN100, a transposon vector constructed to perform in vivo transposition primarily in oral streptococci. Compared to in vitro transposition systems the conditional replicative features of the plasmid, and the inducible expression of the mariner Himar1 transposase, makes pMN100 particularly useful for bacterial strains showing a low transformation frequency. We outline how to transform plasmid pMN100 into Streptococcus mutans, carry out transposon mutagenesis, and determine the chromosomal location of inserted transposons. It is our prospect that the protocols can be used as guidelines for transposon mutagenesis in S. mutans as well as other species of streptococci.
Collapse
Affiliation(s)
- Martin Nilsson
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Michael Givskov
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark.,Singapore Center for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Tim Tolker-Nielsen
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark.
| |
Collapse
|
6
|
Schlechter RO, Jun H, Bernach M, Oso S, Boyd E, Muñoz-Lintz DA, Dobson RCJ, Remus DM, Remus-Emsermann MNP. Chromatic Bacteria - A Broad Host-Range Plasmid and Chromosomal Insertion Toolbox for Fluorescent Protein Expression in Bacteria. Front Microbiol 2018; 9:3052. [PMID: 30631309 PMCID: PMC6315172 DOI: 10.3389/fmicb.2018.03052] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 11/27/2018] [Indexed: 12/26/2022] Open
Abstract
Differential fluorescent labeling of bacteria has become instrumental for many aspects of microbiological research, such as the study of biofilm formation, bacterial individuality, evolution, and bacterial behavior in complex environments. We designed a variety of plasmids, each bearing one of eight unique, constitutively expressed fluorescent protein genes in conjunction with one of four different antibiotic resistance combinations. The fluorophores mTagBFP2, mTurquoise2, sGFP2, mClover3, sYFP2, mOrange2, mScarlet-I, and mCardinal, encoding for blue, cyan, green, green-yellow, yellow, orange, red, and far-red fluorescent proteins, respectively, were combined with selectable markers conferring tetracycline, gentamicin, kanamycin, and/or chloramphenicol resistance. These constructs were cloned into three different plasmid backbones: a broad host-range plasmid, a Tn5 transposon delivery plasmid, and a Tn7 transposon delivery plasmid. The utility of the plasmids and transposons was tested in bacteria from the phyla Actinobacteria, Proteobacteria, and Bacteroidetes. We were able to tag representatives from the phylum Proteobacteria at least via our Tn5 transposon delivery system. The present study enables labeling bacteria with a set of plasmids available to the community. One potential application of fluorescently-tagged bacterial species is the study of bacteria-bacteria, bacteria-host, and bacteria-environment interactions.
Collapse
Affiliation(s)
- Rudolf O. Schlechter
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
| | - Hyunwoo Jun
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Michał Bernach
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
| | - Simisola Oso
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Erica Boyd
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Dian A. Muñoz-Lintz
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Renwick C. J. Dobson
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
- Bio21 Molecular Science and Biotechnology Institute, Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Daniela M. Remus
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
- Protein Science & Engineering, Callaghan Innovation, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Mitja N. P. Remus-Emsermann
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
| |
Collapse
|
7
|
Ding Q, Tan KS. Himar1 Transposon for Efficient Random Mutagenesis in Aggregatibacter actinomycetemcomitans. Front Microbiol 2017; 8:1842. [PMID: 29018421 PMCID: PMC5622930 DOI: 10.3389/fmicb.2017.01842] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 09/08/2017] [Indexed: 12/14/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans is the primary etiological agent of aggressive periodontal disease. Identification of novel virulence factors at the genome-wide level is hindered by lack of efficient genetic tools to perform mutagenesis in this organism. The Himar1 mariner transposon is known to yield a random distribution of insertions in an organism’s genome with requirement for only a TA dinucleotide target and is independent of host-specific factors. However, the utility of this system in A. actinomycetemcomitans is unknown. In this study, we found that Himar1 transposon mutagenesis occurs at a high frequency (×10-4), and can be universally applied to wild-type A. actinomycetemcomitans strains of serotypes a, b, and c. The Himar1 transposon inserts were stably inherited in A. actinomycetemcomitans transconjugants in the absence of antibiotics. A library of 16,000 mutant colonies of A. actinomycetemcomitans was screened for reduced biofilm formation. Mutants with transposon inserts in genes encoding pilus, putative ion transporters, multidrug resistant proteins, transcription regulators and enzymes involved in the synthesis of extracellular polymeric substance, bacterial metabolism and stress response were discovered in this screen. Our results demonstrated the utility of the Himar1 mutagenesis system as a novel genetic tool for functional genomic analysis in A. actinomycetemcomitans.
Collapse
Affiliation(s)
- Qinfeng Ding
- Faculty of Dentistry, National University of Singapore, Singapore, Singapore
| | - Kai Soo Tan
- Faculty of Dentistry, National University of Singapore, Singapore, Singapore
| |
Collapse
|
8
|
The dlt genes play a role in antimicrobial tolerance of Streptococcus mutans biofilms. Int J Antimicrob Agents 2016; 48:298-304. [DOI: 10.1016/j.ijantimicag.2016.06.019] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/27/2016] [Accepted: 06/05/2016] [Indexed: 11/23/2022]
|
9
|
Liu R, Zhang P, Su Y, Lin H, Zhang H, Yu L, Ma Z, Fan H. A novel suicide shuttle plasmid for Streptococcus suis serotype 2 and Streptococcus equi ssp. zooepidemicus gene mutation. Sci Rep 2016; 6:27133. [PMID: 27256117 PMCID: PMC4891806 DOI: 10.1038/srep27133] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 05/13/2016] [Indexed: 01/30/2023] Open
Abstract
The mariner-based Himar1 system has been utilized for creating mutant libraries of many Gram-positive bacteria. Streptococcus suis serotype 2 (SS2) and Streptococcus equi ssp. zooepidemicus (SEZ) are primary pathogens of swine that threaten the swine industry in China. To provide a forward-genetics technology for finding virulent phenotype-related genes in these two pathogens, we constructed a novel temperature-sensitive suicide shuttle plasmid, pMar4s, which contains the Himar1 system transposon, TnYLB-1, and the Himar1 C9 transposase from pMarA and the repTAs temperature-sensitive fragment from pSET4s. The kanamycin (Kan) resistance gene was in the TnYLB-1 transposon. Temperature sensitivity and Kan resistance allowed the selection of mutant strains and construction of the mutant library. The SS2 and SEZ mutant libraries were successfully constructed using the pMar4s plasmid. Inverse-Polymerase Chain Reaction (Inverse-PCR) results revealed large variability in transposon insertion sites and that the library could be used for phenotype alteration screening. The thiamine biosynthesis gene apbE was screened for its influence on SS2 anti-phagocytosis; likewise, the sagF gene was identified to be a hemolytic activity-related gene in SEZ. pMar4s was suitable for mutant library construction, providing more information regarding SS2 and SEZ virulence factors and illustrating the pathogenesis of swine streptococcosis.
Collapse
Affiliation(s)
- Rui Liu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ping Zhang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yiqi Su
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Huixing Lin
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Hui Zhang
- China Animal Health and Epidemiology Center, Qingdao, 266000, China
| | - Lei Yu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhe Ma
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Hongjie Fan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| |
Collapse
|