1
|
Alcorlo M, Abdullah MR, Steil L, Sotomayor F, López-de Oro L, de Castro S, Velázquez S, Kohler TP, Jiménez E, Medina A, Usón I, Keller LE, Bradshaw JL, McDaniel LS, Camarasa MJ, Völker U, Hammerschmidt S, Hermoso JA. Molecular and structural basis of oligopeptide recognition by the Ami transporter system in pneumococci. PLoS Pathog 2024; 20:e1011883. [PMID: 38838057 PMCID: PMC11192437 DOI: 10.1371/journal.ppat.1011883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 06/21/2024] [Accepted: 04/30/2024] [Indexed: 06/07/2024] Open
Abstract
ATP-binding cassette (ABC) transport systems are crucial for bacteria to ensure sufficient uptake of nutrients that are not produced de novo or improve the energy balance. The cell surface of the pathobiont Streptococcus pneumoniae (pneumococcus) is decorated with a substantial array of ABC transporters, critically influencing nasopharyngeal colonization and invasive infections. Given the auxotrophic nature of pneumococci for certain amino acids, the Ami ABC transporter system, orchestrating oligopeptide uptake, becomes indispensable in host compartments lacking amino acids. The system comprises five exposed Oligopeptide Binding Proteins (OBPs) and four proteins building the ABC transporter channel. Here, we present a structural analysis of all the OBPs in this system. Multiple crystallographic structures, capturing both open and closed conformations along with complexes involving chemically synthesized peptides, have been solved at high resolution providing insights into the molecular basis of their diverse peptide specificities. Mass spectrometry analysis of oligopeptides demonstrates the unexpected remarkable promiscuity of some of these proteins when expressed in Escherichia coli, displaying affinity for a wide range of peptides. Finally, a model is proposed for the complete Ami transport system in complex with its various OBPs. We further disclosed, through in silico modelling, some essential structural changes facilitating oligopeptide transport into the cellular cytoplasm. Thus, the structural analysis of the Ami system provides valuable insights into the mechanism and specificity of oligopeptide binding by the different OBPs, shedding light on the intricacies of the uptake mechanism and the in vivo implications for this human pathogen.
Collapse
Affiliation(s)
- Martín Alcorlo
- Department of Crystallography and Structural Biology, Institute of Physical-Chemistry “Blas Cabrera”, Spanish National Research Council (CSIC), Madrid; Spain
| | - Mohammed R. Abdullah
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald; Germany
| | - Leif Steil
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University Medicine Greifswald, Greifswald; Germany
| | - Francisco Sotomayor
- Department of Crystallography and Structural Biology, Institute of Physical-Chemistry “Blas Cabrera”, Spanish National Research Council (CSIC), Madrid; Spain
| | - Laura López-de Oro
- Department of Crystallography and Structural Biology, Institute of Physical-Chemistry “Blas Cabrera”, Spanish National Research Council (CSIC), Madrid; Spain
| | | | | | - Thomas P. Kohler
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald; Germany
| | - Elisabet Jiménez
- Crystallographic Methods, Institute of Molecular Biology of Barcelona (IBMB-CSIC), Barcelona Science Park, Helix Building, Barcelona; Spain
| | - Ana Medina
- Crystallographic Methods, Institute of Molecular Biology of Barcelona (IBMB-CSIC), Barcelona Science Park, Helix Building, Barcelona; Spain
| | - Isabel Usón
- Crystallographic Methods, Institute of Molecular Biology of Barcelona (IBMB-CSIC), Barcelona Science Park, Helix Building, Barcelona; Spain
- ICREA, Institució Catalana de Recerca i Estudis Avançats, Barcelona; Spain
| | - Lance E. Keller
- Center for Immunology and Microbial Research, University of Mississippi Medical Center, Jackson, Mississippi; United States of America
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi; United States of America
| | - Jessica L. Bradshaw
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, Mississippi; United States of America
| | - Larry S. McDaniel
- Center for Immunology and Microbial Research, University of Mississippi Medical Center, Jackson, Mississippi; United States of America
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi; United States of America
| | | | - Uwe Völker
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University Medicine Greifswald, Greifswald; Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald; Germany
| | - Juan A. Hermoso
- Department of Crystallography and Structural Biology, Institute of Physical-Chemistry “Blas Cabrera”, Spanish National Research Council (CSIC), Madrid; Spain
| |
Collapse
|
2
|
Yao M, Wang K, Song G, Hu Y, Chen J, Li T, Liang L, Wu J, Xu H, Wang L, Zheng Y, Zhang X, Yin Y, Yao S, Wu K. Transcriptional regulation of TacL-mediated lipoteichoic acids biosynthesis by ComE during competence impacts pneumococcal transformation. Front Cell Infect Microbiol 2024; 14:1375312. [PMID: 38779562 PMCID: PMC11109429 DOI: 10.3389/fcimb.2024.1375312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 04/08/2024] [Indexed: 05/25/2024] Open
Abstract
Competence development is essential for bacterial transformation since it enables bacteria to take up free DNA from the surrounding environment. The regulation of teichoic acid biosynthesis is tightly controlled during pneumococcal competence; however, the mechanism governing this regulation and its impact on transformation remains poorly understood. We demonstrated that a defect in lipoteichoic acid ligase (TacL)-mediated lipoteichoic acids (LTAs) biosynthesis was associated with impaired pneumococcal transformation. Using a fragment of tacL regulatory probe as bait in a DNA pulldown assay, we successfully identified several regulatory proteins, including ComE. Electrophoretic mobility shift assays revealed that phosphomimetic ComE, but not wild-type ComE, exhibited specific binding to the probe. DNase I footprinting assays revealed the specific binding sequences encompassing around 30 base pairs located 31 base pairs upstream from the start codon of tacL. Expression of tacL was found to be upregulated in the ΔcomE strain, and the addition of exogenous competence-stimulating peptide repressed the tacL transcription in the wild-type strain but not the ΔcomE mutant, indicating that ComE exerted a negative regulatory effect on the transcription of tacL. Mutation in the JH2 region of tacL upstream regulatory sequence led to increased LTAs abundance and displayed higher transformation efficiency. Collectively, our work identified the regulatory mechanisms that control LTAs biosynthesis during competence and thereby unveiled a repression mechanism underlying pneumococcal transformation.
Collapse
Affiliation(s)
- Miao Yao
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Kun Wang
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Guangming Song
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Yumeng Hu
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Jiali Chen
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Tingting Li
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Longying Liang
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Jie Wu
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Hongmei Xu
- Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Libin Wang
- Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Yuqiang Zheng
- Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Xuemei Zhang
- Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Yibing Yin
- Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Shifei Yao
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Kaifeng Wu
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| |
Collapse
|
3
|
Wu X, Alibayov B, Xiang X, Lattar SM, Sakai F, Medders AA, Antezana B, Keller L, Vidal AGJ, Tzeng YL, Robinson DA, Stephens D, Yu Y, Vidal JE. Ultrastructural, metabolic and genetic determinants of the acquisition of macrolide resistance by Streptococcus pneumoniae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.27.573471. [PMID: 38234816 PMCID: PMC10793443 DOI: 10.1101/2023.12.27.573471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Aim Streptococcus pneumoniae (Spn) acquires genes for macrolide resistance, MEGA or ermB, in the human host. These genes are carried either in the chromosome, or on integrative conjugative elements (ICEs). Here, we investigated molecular determinants of the acquisition of macrolide resistance. Methods and Results Whole genome analysis was conducted for 128 macrolide-resistant pneumococcal isolates to identify the presence of MEGA (44.5%, 57/128) or ermB (100%), and recombination events in Tn916-related elements or in the locus comCDE encoding competence genes. Confocal and electron microscopy studies demonstrated that, during the acquisition of macrolide resistance, pneumococcal strains formed clusters of varying size, with the largest aggregates having a median size of ~1600 μm2. Remarkably, these pneumococcal aggregates comprise both encapsulated and nonencapsulated pneumococci, exhibited physical interaction, and spanned extracellular and intracellular compartments. We assessed the recombination frequency (rF) for the acquisition of macrolide resistance by a recipient D39 strain, from pneumococcal strains carrying MEGA (~5.4 kb) in the chromone, or in large ICEs (>23 kb). Notably, the rF for the acquisition of MEGA, whether in the chromosome or carried on an ICE was similar. However, the rF adjusted to the acquisition of the full-length ICE (~52 kb), compared to that of the capsule locus (~23 kb) that is acquired by transformation, was three orders of magnitude higher. Finally, metabolomics studies revealed a link between the acquisition of ICE and the metabolic pathways involving nicotinic acid and sucrose. Conclusions Extracellular and intracellular pneumococcal clusters facilitate the acquisition of full-length ICE at a rF higher than that of typical transformation events, involving distinct metabolic changes that present potential targets for interventions.
Collapse
Affiliation(s)
- Xueqing Wu
- Department of Infectious Diseases, Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310052, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou 310052, China
| | - Babek Alibayov
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson MS 39056, United States
| | - Xi Xiang
- Department of Clinical Laboratory, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua 321000, China
| | - Santiago M. Lattar
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta GA 30322, United States
| | - Fuminori Sakai
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta GA 30322, United States
| | - Austin A. Medders
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson MS 39056, United States
| | - Brenda Antezana
- Department of Medicine, School of Medicine, Emory University, Atlanta GA 30322, United States
| | - Lance Keller
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson MS 39056, United States
| | - Ana G. J. Vidal
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson MS 39056, United States
| | - Yih-Ling Tzeng
- Department of Medicine, School of Medicine, Emory University, Atlanta GA 30322, United States
| | - D. Ashley Robinson
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson MS 39056, United States
| | - David Stephens
- Department of Medicine, School of Medicine, Emory University, Atlanta GA 30322, United States
| | - Yunsong Yu
- Department of Infectious Diseases, Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310052, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou 310052, China
| | - Jorge E. Vidal
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson MS 39056, United States
| |
Collapse
|
4
|
Antezana BS, Lohsen S, Wu X, Vidal JE, Tzeng YL, Stephens DS. Dissemination of Tn 916-Related Integrative and Conjugative Elements in Streptococcus pneumoniae Occurs by Transformation and Homologous Recombination in Nasopharyngeal Biofilms. Microbiol Spectr 2023; 11:e0375922. [PMID: 36912669 PMCID: PMC10101023 DOI: 10.1128/spectrum.03759-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 02/02/2023] [Indexed: 03/14/2023] Open
Abstract
Multidrug resistance in Streptococcus pneumoniae (or pneumococcus) continues to be a global challenge. An important class of antibiotic resistance determinants disseminating in S. pneumoniae are >20-kb Tn916-related integrative and conjugative elements (ICEs), such as Tn2009, Tn6002, and Tn2010. Although conjugation has been implicated as the transfer mechanism for ICEs in several bacteria, including S. pneumoniae, the molecular basis for widespread dissemination of pneumococcal Tn916-related ICEs remains to be fully elucidated. We found that Tn2009 acquisition was not detectable via in vitro transformation nor conjugative mating with donor GA16833, yielding a transfer frequency of <10-7. GA16833 Tn2009 conjugative gene expression was not significantly induced, and ICE circular intermediate formation was not detected in biofilms. Consistently, Tn2009 transfer efficiency in biofilms was not affected by deletion of the ICE conjugative gene ftsK. However, GA16833 Tn2009 transfer occurred efficiently at a recombination frequency (rF) of 10-4 in dual-strain biofilms formed in a human nasopharyngeal cell bioreactor. DNase I addition and deletions of the early competence gene comE or transformation apparatus genes comEA and comEC in the D39 recipient strain prevented Tn2009 acquisition (rF of <10-7). Genome sequencing and single nucleotide polymorphism analyses of independent recombinants of recipient genotype identified ~33- to ~55-kb donor DNAs containing intact Tn2009, supporting homologous recombination. Additional pneumococcal donor and recipient combinations were demonstrated to efficiently transfer Tn916-related ICEs at a rF of 10-4 in the biofilms. Tn916-related ICEs horizontally disseminate at high frequency in human nasopharyngeal S. pneumoniae biofilms by transformation and homologous recombination of >30-kb DNA fragments into the pneumococcal genome. IMPORTANCE The World Health Organization has designated Streptococcus pneumoniae as a priority pathogen for research and development of new drug treatments due to extensive multidrug resistance. Multiple strains of S. pneumoniae colonize and form mixed biofilms in the human nasopharynx, which could enable exchange of antibiotic resistance determinants. Tn916-related integrative and conjugative elements (ICEs) are largely responsible for the widespread presence of macrolide and tetracycline resistance in S. pneumoniae. Utilizing a system that simulates colonization of donor and recipient S. pneumoniae strains in the human nasopharynx, efficient transfer of Tn916-related ICEs occurred in human nasopharyngeal biofilms, in contrast to in vitro conditions of planktonic cells with exogenous DNA. This high-frequency Tn916-related ICE transfer between S. pneumoniae strains in biofilms was due to transformation and homologous recombination, not conjugation. Understanding the molecular mechanism for dissemination of Tn916-related ICEs can facilitate the design of new strategies to combat antibiotic resistance.
Collapse
Affiliation(s)
- Brenda S. Antezana
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Emory University Laney Graduate School, Atlanta, Georgia, USA
| | - Sarah Lohsen
- Department of Medicine, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Xueqing Wu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University College of Medicine, Hangzhou, China
| | - Jorge E. Vidal
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Yih-Ling Tzeng
- Department of Medicine, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, USA
| | - David S. Stephens
- Department of Medicine, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, USA
| |
Collapse
|
5
|
Michaelis C, Grohmann E. Horizontal Gene Transfer of Antibiotic Resistance Genes in Biofilms. Antibiotics (Basel) 2023; 12:antibiotics12020328. [PMID: 36830238 PMCID: PMC9952180 DOI: 10.3390/antibiotics12020328] [Citation(s) in RCA: 49] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/08/2023] Open
Abstract
Most bacteria attach to biotic or abiotic surfaces and are embedded in a complex matrix which is known as biofilm. Biofilm formation is especially worrisome in clinical settings as it hinders the treatment of infections with antibiotics due to the facilitated acquisition of antibiotic resistance genes (ARGs). Environmental settings are now considered as pivotal for driving biofilm formation, biofilm-mediated antibiotic resistance development and dissemination. Several studies have demonstrated that environmental biofilms can be hotspots for the dissemination of ARGs. These genes can be encoded on mobile genetic elements (MGEs) such as conjugative and mobilizable plasmids or integrative and conjugative elements (ICEs). ARGs can be rapidly transferred through horizontal gene transfer (HGT) which has been shown to occur more frequently in biofilms than in planktonic cultures. Biofilm models are promising tools to mimic natural biofilms to study the dissemination of ARGs via HGT. This review summarizes the state-of-the-art of biofilm studies and the techniques that visualize the three main HGT mechanisms in biofilms: transformation, transduction, and conjugation.
Collapse
|
6
|
Miron VD, Săndulescu O, Craiu M. Comment on: "Prevalence, Antibiotic Susceptibility Profile and Associated Factors of Group A Streptococcal Pharyngitis Among Pediatric Patients with Acute Pharyngitis in Gondar, Northwest Ethiopia" [Letter]. Infect Drug Resist 2023; 16:2783-2785. [PMID: 37187485 PMCID: PMC10178995 DOI: 10.2147/idr.s418143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 05/03/2023] [Indexed: 05/17/2023] Open
Affiliation(s)
- Victor Daniel Miron
- Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- Correspondence: Victor Daniel Miron, Carol Davila University of Medicine and Pharmacy, 127, Lacul Tei Street, Second District, Bucharest, 020382, Romania, Email
| | - Oana Săndulescu
- Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- National Institute for Infectious Diseases “Prof. Dr. Matei Balș”, Bucharest, Romania
| | - Mihai Craiu
- Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- National Institute for Mother and Child Health “Alessandrescu-Rusescu”, Bucharest, Romania
| |
Collapse
|
7
|
Ongpipattanakul C, Desormeaux EK, DiCaprio A, van der Donk WA, Mitchell DA, Nair SK. Mechanism of Action of Ribosomally Synthesized and Post-Translationally Modified Peptides. Chem Rev 2022; 122:14722-14814. [PMID: 36049139 PMCID: PMC9897510 DOI: 10.1021/acs.chemrev.2c00210] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a natural product class that has undergone significant expansion due to the rapid growth in genome sequencing data and recognition that they are made by biosynthetic pathways that share many characteristic features. Their mode of actions cover a wide range of biological processes and include binding to membranes, receptors, enzymes, lipids, RNA, and metals as well as use as cofactors and signaling molecules. This review covers the currently known modes of action (MOA) of RiPPs. In turn, the mechanisms by which these molecules interact with their natural targets provide a rich set of molecular paradigms that can be used for the design or evolution of new or improved activities given the relative ease of engineering RiPPs. In this review, coverage is limited to RiPPs originating from bacteria.
Collapse
Affiliation(s)
- Chayanid Ongpipattanakul
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Emily K. Desormeaux
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Adam DiCaprio
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Wilfred A. van der Donk
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.,Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.,Department of Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.,Departments of Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, USA.,Corresponding authors Wilfred A. van der Donk, , 217-244-5360, Douglas A. Mitchell, , 217-333-1345, Satish K. Nair, , 217-333-0641
| | - Douglas A. Mitchell
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.,Department of Microbiology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.,Departments of Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, USA.,Corresponding authors Wilfred A. van der Donk, , 217-244-5360, Douglas A. Mitchell, , 217-333-1345, Satish K. Nair, , 217-333-0641
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.,Departments of Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, USA.,Corresponding authors Wilfred A. van der Donk, , 217-244-5360, Douglas A. Mitchell, , 217-333-1345, Satish K. Nair, , 217-333-0641
| |
Collapse
|
8
|
Valente C, Cruz AR, Henriques AO, Sá-Leão R. Intra-Species Interactions in Streptococcus pneumoniae Biofilms. Front Cell Infect Microbiol 2022; 11:803286. [PMID: 35071049 PMCID: PMC8767070 DOI: 10.3389/fcimb.2021.803286] [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: 10/27/2021] [Accepted: 12/14/2021] [Indexed: 11/13/2022] Open
Abstract
Streptococcus pneumoniae is a human pathogen responsible for high morbidity and mortality worldwide. Disease is incidental and is preceded by asymptomatic nasopharyngeal colonization in the form of biofilms. Simultaneous colonization by multiple pneumococcal strains is frequent but remains poorly characterized. Previous studies, using mostly laboratory strains, showed that pneumococcal strains can reciprocally affect each other's colonization ability. Here, we aimed at developing a strategy to investigate pneumococcal intra-species interactions occurring in biofilms. A 72h abiotic biofilm model mimicking long-term colonization was applied to study eight pneumococcal strains encompassing 6 capsular types and 7 multilocus sequence types. Strains were labeled with GFP or RFP, generating two fluorescent variants for each. Intra-species interactions were evaluated in dual-strain biofilms (1:1 ratio) using flow cytometry. Confocal microscopy was used to image representative biofilms. Twenty-eight dual-strain combinations were tested. Interactions of commensalism, competition, amensalism and neutralism were identified. The outcome of an interaction was independent of the capsular and sequence type of the strains involved. Confocal imaging of biofilms confirmed the positive, negative and neutral effects that pneumococci can exert on each other. In conclusion, we developed an experimental approach that successfully discriminates pneumococcal strains growing in mixed biofilms, which enables the identification of intra-species interactions. Several types of interactions occur among pneumococci. These observations are a starting point to study the mechanisms underlying those interactions.
Collapse
Affiliation(s)
- Carina Valente
- Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Ana R Cruz
- Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Adriano O Henriques
- Laboratory of Microbial Development, Instituto de Tecnologia Química e Biológica António Xavier, Oeiras, Portugal
| | - Raquel Sá-Leão
- Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| |
Collapse
|
9
|
Galimov ER, Gems D. Death happy: adaptive ageing and its evolution by kin selection in organisms with colonial ecology. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190730. [PMID: 33678027 DOI: 10.1098/rstb.2019.0730] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Standard evolutionary theory, supported by mathematical modelling of outbred, dispersed populations predicts that ageing is not an adaptation. We recently argued that in clonal, viscous populations, programmed organismal death could promote fitness through social benefits and has, in some organisms (e.g. Caenorhabditis elegans), evolved to shorten lifespan. Here, we review previous adaptive death theory, including consumer sacrifice, biomass sacrifice and defensive sacrifice types of altruistic adaptive death. In addition, we discuss possible adaptive death in certain semelparous fish, coevolution of reproductive and adaptive death, and adaptive reproductive senescence in C. elegans. We also describe findings from recent tests for the existence of adaptive death in C. elegans using computer modelling. Such models have provided new insights into how trade-offs between fitness at the individual and colony levels mean that senescent changes can be selected traits. Exploring further the relationship between adaptive death and social interactions, we consider examples where adaptive death results more from action of kin than from self-destructive mechanisms and, to describe this, introduce the term adaptive killing of kin. This article is part of the theme issue 'Ageing and sociality: why, when and how does sociality change ageing patterns?'
Collapse
Affiliation(s)
- Evgeniy R Galimov
- Institute of Healthy Ageing, and Research Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - David Gems
- Institute of Healthy Ageing, and Research Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| |
Collapse
|
10
|
Competence-Stimulating-Peptide-Dependent Localized Cell Death and Extracellular DNA Production in Streptococcus mutans Biofilms. Appl Environ Microbiol 2020; 86:AEM.02080-20. [PMID: 32948520 DOI: 10.1128/aem.02080-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/14/2020] [Indexed: 02/06/2023] Open
Abstract
Extracellular DNA (eDNA) is a biofilm component that contributes to the formation and structural stability of biofilms. Streptococcus mutans, a major cariogenic bacterium, induces eDNA-dependent biofilm formation under specific conditions. Since cell death can result in the release and accumulation of DNA, the dead cells in biofilms are a source of eDNA. However, it remains unknown how eDNA is released from dead cells and is localized within S. mutans biofilms. We focused on cell death induced by the extracellular signaling peptide called competence-stimulating peptide (CSP). We demonstrate that nucleic acid release into the extracellular environment occurs in a subpopulation of dead cells. eDNA production induced by CSP was highly dependent on the lytF gene, which encodes an autolysin. Although lytF expression was induced bimodally by CSP, lytF-expressing cells further divided into surviving cells and eDNA-producing dead cells. Moreover, we found that lytF-expressing cells were abundant near the bottom of the biofilm, even when all cells in the biofilm received the CSP signal. Dead cells and eDNA were also abundantly present near the bottom of the biofilm. The number of lytF-expressing cells in biofilms was significantly higher than that in planktonic cultures, which suggests that adhesion to the substratum surface is important for the induction of lytF expression. The deletion of lytF resulted in reduced adherence to a polystyrene surface. These results suggest that lytF expression and eDNA production induced near the bottom of the biofilm contribute to a firmly attached and structurally stable biofilm.IMPORTANCE Bacterial communities encased by self-produced extracellular polymeric substances (EPSs), known as biofilms, have a wide influence on human health and environmental problems. The importance of biofilm research has increased, as biofilms are the preferred bacterial lifestyle in nature. Furthermore, in recent years it has been noted that the contribution of phenotypic heterogeneity within biofilms requires analysis at the single-cell or subpopulation level to understand bacterial life strategies. In Streptococcus mutans, a cariogenic bacterium, extracellular DNA (eDNA) contributes to biofilm formation. However, it remains unclear how and where the cells produce eDNA within the biofilm. We focused on LytF, an autolysin that is induced by extracellular peptide signals. We used single-cell level imaging techniques to analyze lytF expression in the biofilm population. Here, we show that S. mutans generates eDNA by inducing lytF expression near the bottom of the biofilm, thereby enhancing biofilm adhesion and structural stability.
Collapse
|
11
|
Contact-Dependent Growth Inhibition in Bacteria: Do Not Get Too Close! Int J Mol Sci 2020; 21:ijms21217990. [PMID: 33121148 PMCID: PMC7662968 DOI: 10.3390/ijms21217990] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 10/24/2020] [Accepted: 10/26/2020] [Indexed: 12/20/2022] Open
Abstract
Over millions of years of evolution, bacteria have developed complex strategies for intra-and interspecies interactions and competition for ecological niches and resources. Contact-dependent growth inhibition systems (CDI) are designed to realize a direct physical contact of one bacterial cell with other cells in proximity via receptor-mediated toxin delivery. These systems are found in many microorganisms including clinically important human pathogens. The main purpose of these systems is to provide competitive advantages for the growth of the population. In addition, non-competitive roles for CDI toxin delivery systems including interbacterial signal transduction and mediators of bacterial collaboration have been suggested. In this review, our goal was to systematize the recent findings on the structure, mechanisms, and purpose of CDI systems in bacterial populations and discuss the potential biological and evolutionary impact of CDI-mediated interbacterial competition and/or cooperation.
Collapse
|
12
|
Wen HQ, Ren HY, Xie GJ, Cao GL, Xing DF, Ren NQ, Liu BF. Synthesized effects of proteomic and extracellular polymeric substance (EPS) revealing the enhanced hydrogen production by formed biofilm of photo-fermentative bacteria. ENVIRONMENT INTERNATIONAL 2020; 139:105683. [PMID: 32244101 DOI: 10.1016/j.envint.2020.105683] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/20/2020] [Accepted: 03/22/2020] [Indexed: 06/11/2023]
Abstract
Photo-fermentative hydrogen production, the new energy production alternative, was greatly enhanced by formed biofilm. To understand the mechanism of enhancement, the intracellular proteome and extracellular polymeric substance (EPS)i during biofilm formation were investigated in this work. Experimental results indicated that a possible and effective altered system could transfer light to hydrogen. Proteins were significantly regulated, for example those related with nitrogenase, flagellin, EPS transportation and DNA duplication were up-regulated while those concerned photosystem were down-regulated. It revealed these changes of proteins contributed to positive activity of key enzymes, improved communication system and increased total light utilization efficiency thus leading to enhanced capacity of hydrogen production. Besides above metabolic changes inside the cells, EPS secreted by the bacteria played an important role in hydrogen production and its yield decided the release of hydrogen. When EPS descended to a lower concentration during biofilm formation, it meant carbon source for EPS synthesis was reduced, and more energy and reducing power could be transferred into hydrogen energy. More importantly, this work found that composition and structure of EPS were efficiently influenced by the formation of biofilm, such as benzene and O-H structure, secondary protein structure and the kinds of protein, which were important to stable biofilm and efficient hydrogen production. Therefore, final hydrogen yield was improved by altered protein and EPS resulted from biofilm formation. This study demonstrated that formation of biofilm is an efficient, ecological and attracting way to the future bio-hydrogen production.
Collapse
Affiliation(s)
- Han-Quan Wen
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, P.O. Box 2614, 73 Huanghe Road, Harbin 150090, China
| | - Hong-Yu Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, P.O. Box 2614, 73 Huanghe Road, Harbin 150090, China
| | - Guo-Jun Xie
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, P.O. Box 2614, 73 Huanghe Road, Harbin 150090, China
| | - Guang-Li Cao
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, P.O. Box 2614, 73 Huanghe Road, Harbin 150090, China
| | - De-Feng Xing
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, P.O. Box 2614, 73 Huanghe Road, Harbin 150090, China
| | - Nan-Qi Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, P.O. Box 2614, 73 Huanghe Road, Harbin 150090, China
| | - Bing-Feng Liu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, P.O. Box 2614, 73 Huanghe Road, Harbin 150090, China.
| |
Collapse
|
13
|
Streptococcus pneumoniae Elaborates Persistent and Prolonged Competent State during Pneumonia-Derived Sepsis. Infect Immun 2020; 88:IAI.00919-19. [PMID: 31988172 DOI: 10.1128/iai.00919-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 01/21/2020] [Indexed: 01/18/2023] Open
Abstract
The competence regulon of pneumococcus regulates both genetic transformation and virulence. However, competence induction during host infection has not been examined. By using the serotype 2 strain D39, we transcriptionally fused the firefly luciferase (luc) to competence-specific genes and spatiotemporally monitored the competence development in a mouse model of pneumonia-derived sepsis. In contrast to the universally reported short transient burst of competent state in vitro, the naturally developed competent state was prolonged and persistent during pneumonia-derived sepsis. The competent state began at approximately 20 h postinfection (hpi) and facilitated systemic invasion and sepsis development and progressed in different manners. In some mice, acute pneumonia quickly led to sepsis and death, accompanied by increasing intensity of the competence signal. In the remaining mice, pneumonia lasted longer, with the competence signal decreasing at first but increasing as the infection became septic. The concentration of pneumococcal inoculum (1 × 106 to 1 × 108 CFU/mouse) and postinfection lung bacterial burden did not appreciably impact the kinetics of competence induction. Exogenously provided competence stimulating peptide 1 (CSP1) failed to modulate the onset kinetics of competence development in vivo The competence shutoff regulator DprA was highly expressed during pneumonia-derived sepsis but failed to turn off the competent state in mice. Competent D39 bacteria propagated the competence signal through cell-to-cell contact rather than the classically described quorum-sensing mechanism. Finally, clinical pneumococcal strains of different serotypes were also able to develop natural competence during pneumonia-derived sepsis.
Collapse
|
14
|
Harnessing the Potential of Killers and Altruists within the Microbial Community: A Possible Alternative to Antibiotic Therapy? Antibiotics (Basel) 2019; 8:antibiotics8040230. [PMID: 31766366 PMCID: PMC6963621 DOI: 10.3390/antibiotics8040230] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/17/2019] [Accepted: 11/19/2019] [Indexed: 12/29/2022] Open
Abstract
In the context of a post-antibiotic era, the phenomenon of microbial allolysis, which is defined as the partial killing of bacterial population induced by other cells of the same species, may take on greater significance. This phenomenon was revealed in some bacterial species such as Streptococcus pneumoniae and Bacillus subtilis, and has been suspected to occur in some other species or genera, such as enterococci. The mechanisms of this phenomenon, as well as its role in the life of microbial populations still form part of ongoing research. Herein, we describe recent developments in allolysis in the context of its practical benefits as a form of cell death that may give rise to developing new strategies for manipulating the life and death of bacterial communities. We highlight how such findings may be viewed with importance and potential within the fields of medicine, biotechnology, and pharmacology.
Collapse
|
15
|
Silva MD, Sillankorva S. Otitis media pathogens – A life entrapped in biofilm communities. Crit Rev Microbiol 2019; 45:595-612. [DOI: 10.1080/1040841x.2019.1660616] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Maria Daniela Silva
- CEB – Centre of Biological Engineering, LIBRO – Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Braga, Portugal
| | - Sanna Sillankorva
- CEB – Centre of Biological Engineering, LIBRO – Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Braga, Portugal
| |
Collapse
|
16
|
Refining the Pneumococcal Competence Regulon by RNA Sequencing. J Bacteriol 2019; 201:JB.00780-18. [PMID: 30885934 PMCID: PMC6560143 DOI: 10.1128/jb.00780-18] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/15/2019] [Indexed: 12/13/2022] Open
Abstract
Streptococcus pneumoniae is an opportunistic human pathogen responsible for over a million deaths every year. Although both vaccination programs and antibiotic therapies have been effective in prevention and treatment of pneumococcal infections, respectively, the sustainability of these solutions is uncertain. The pneumococcal genome is highly flexible, leading to vaccine escape and antibiotic resistance. This flexibility is predominantly facilitated by competence, a state allowing the cell to take up and integrate exogenous DNA. Thus, it is essential to obtain a detailed overview of gene expression during competence. This is stressed by the fact that administration of several classes of antibiotics can lead to competence. Previous studies on the competence regulon were performed with microarray technology and were limited to an incomplete set of known genes. Using RNA sequencing combined with an up-to-date genome annotation, we provide an updated overview of competence-regulated genes. Competence for genetic transformation allows the opportunistic human pathogen Streptococcus pneumoniae to take up exogenous DNA for incorporation into its own genome. This ability may account for the extraordinary genomic plasticity of this bacterium, leading to antigenic variation, vaccine escape, and the spread of antibiotic resistance. The competence system has been thoroughly studied, and its regulation is well understood. Additionally, over the last decade, several stress factors have been shown to trigger the competent state, leading to the activation of several stress response regulons. The arrival of next-generation sequencing techniques allowed us to update the competence regulon, the latest report on which still depended on DNA microarray technology. Enabled by the availability of an up-to-date genome annotation, including transcript boundaries, we assayed time-dependent expression of all annotated features in response to competence induction, were able to identify the affected promoters, and produced a more complete overview of the various regulons activated during the competence state. We show that 4% of all annotated genes are under direct control of competence regulators ComE and ComX, while the expression of a total of up to 17% of all genes is affected, either directly or indirectly. Among the affected genes are various small RNAs with an as-yet-unknown function. Besides the ComE and ComX regulons, we were also able to refine the CiaR, VraR (LiaR), and BlpR regulons, underlining the strength of combining transcriptome sequencing (RNA-seq) with a well-annotated genome. IMPORTANCEStreptococcus pneumoniae is an opportunistic human pathogen responsible for over a million deaths every year. Although both vaccination programs and antibiotic therapies have been effective in prevention and treatment of pneumococcal infections, respectively, the sustainability of these solutions is uncertain. The pneumococcal genome is highly flexible, leading to vaccine escape and antibiotic resistance. This flexibility is predominantly facilitated by competence, a state allowing the cell to take up and integrate exogenous DNA. Thus, it is essential to obtain a detailed overview of gene expression during competence. This is stressed by the fact that administration of several classes of antibiotics can lead to competence. Previous studies on the competence regulon were performed with microarray technology and were limited to an incomplete set of known genes. Using RNA sequencing combined with an up-to-date genome annotation, we provide an updated overview of competence-regulated genes.
Collapse
|
17
|
Popp PF, Mascher T. Coordinated Cell Death in Isogenic Bacterial Populations: Sacrificing Some for the Benefit of Many? J Mol Biol 2019; 431:4656-4669. [PMID: 31029705 DOI: 10.1016/j.jmb.2019.04.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/11/2019] [Accepted: 04/14/2019] [Indexed: 01/22/2023]
Abstract
Antibiotics are classically perceived as biological weapons that bacteria produce to hold their ground against competing species in their natural habitat. But in the context of multicellular differentiation processes, antimicrobial compounds sometimes also play a role in intraspecies competition, resulting in the death of a sub-population of genetically identical siblings for the benefit of the population. Such a strategy is based on the diversification and hence phenotypic heterogeneity of an isogenic bacterial population. This review article will address three such phenomena. In Bacillus subtilis, cannibalism is a differentiation strategy that enhances biofilm formation, prolongs or potentially even prevents full commitment to endospore formation under starvation conditions, and protects cells within the biofilm against competing species. The nutrients released by lysed cells can be used by the toxin producers, thereby delaying the full activation of the master regulator of sporulation. A related strategy is associated with the initiation of competence development under nutrient excess in Streptococcus pneumoniae. This process, termed fratricide, causes allolysis in a sub-population and is thought to enhance genetic diversity within the species. In Myxococcus xanthus, a large fraction of the population undergoes programmed cell death during the formation of fruiting bodies. This sacrifice ensures the survival of the sporulating sub-population by providing nutrients and hence energy to complete this differentiation process. The biological relevance and underlying regulatory mechanisms of these three processes will be discussed in order to extract common features of such strategies. Moreover, open questions and future challenges will be addressed.
Collapse
Affiliation(s)
- Philipp F Popp
- Institute of Microbiology, Technische Universität (TU) Dresden, 01062 Dresden, Germany
| | - Thorsten Mascher
- Institute of Microbiology, Technische Universität (TU) Dresden, 01062 Dresden, Germany.
| |
Collapse
|
18
|
Chao Y, Bergenfelz C, Hakansson AP. Growing and Characterizing Biofilms Formed by Streptococcus pneumoniae. Methods Mol Biol 2019; 1968:147-171. [PMID: 30929213 DOI: 10.1007/978-1-4939-9199-0_13] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
It is estimated that over 80% of bacterial infections are associated with biofilm formation. Biofilms are organized bacterial communities formed on abiotic surfaces, such as implanted or inserted medical devices, or on biological surfaces, such as epithelial linings and mucosal surfaces. Biofilm growth is advantageous for the bacterial organism as it protects the bacteria from antimicrobial host factors and allows the bacteria to reside in the host without causing excessive inflammation. Like many other opportunistic pathogens of the respiratory tract, Streptococcus pneumoniae forms biofilms during asymptomatic carriage, which promotes, among other things, persistence in the niche, intraspecies and interspecies communication, and spread of bacterial DNA. Changes within the colonizing environment resulting from host assaults, such as virus infection, can induce biofilm dispersion where bacteria leave the biofilm and disseminate to other sites with ensuing infection. In this chapter, we present methodology to form complex biofilms in the nasopharynx of mice and to evaluate the biofilm structure and function in this environment. Furthermore, we present methods that recapitulate this biofilm phenotype in vitro by incorporating crucial factors associated with the host environment and describe how these models can be used to study biofilm function, transformation, and dispersion.
Collapse
Affiliation(s)
- Yashuan Chao
- Wallenberg Laboratory, Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Caroline Bergenfelz
- Wallenberg Laboratory, Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Anders P Hakansson
- Wallenberg Laboratory, Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University, Malmö, Sweden.
| |
Collapse
|
19
|
Manna S, Waring A, Papanicolaou A, Hall NE, Bozinovski S, Dunne EM, Satzke C. The transcriptomic response of Streptococcus pneumoniae following exposure to cigarette smoke extract. Sci Rep 2018; 8:15716. [PMID: 30356075 PMCID: PMC6200755 DOI: 10.1038/s41598-018-34103-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 10/11/2018] [Indexed: 11/09/2022] Open
Abstract
Exposure to cigarette smoke is a risk factor for respiratory diseases. Although most research has focused on its effects on the host, cigarette smoke can also directly affect respiratory pathogens, in some cases enhancing virulence. Streptococcus pneumoniae (the pneumococcus) is a leading cause of community-acquired pneumonia worldwide, however data on the effects of cigarette smoke on the pneumococcus are sparse. Using RNA-seq, we show that pneumococci exposed to cigarette smoke extract in a concentrated acute exposure in vitro model initiate a 'survival' transcriptional response including the upregulation of detoxification enzymes, efflux pumps and osmoregulator transporters, as well as the downregulation of fatty acid and D-alanyl lipoteichoic acid biosynthesis genes. Except for the downregulation of the pneumolysin gene, there were no changes in the expression of major virulence factors following exposure to cigarette smoke. Compared to unexposed pneumococci, smoke-exposed pneumococci did not exhibit any changes in viability, adherence, hydrophobicity or cell lysis susceptibility. In this study, we demonstrate that pneumococci adapt to acute noxious cigarette smoke exposure by inducing a gene expression signature that allows the bacteria to resist its harmful effects.
Collapse
Affiliation(s)
- Sam Manna
- Pneumococcal Research, Murdoch Children's Research Institute, Infection and Immunity, Parkville, 3052, Australia.
| | - Alicia Waring
- Pneumococcal Research, Murdoch Children's Research Institute, Infection and Immunity, Parkville, 3052, Australia
| | - Angelica Papanicolaou
- Chronic Infectious and Inflammatory Disease Programme, School of Health & Biomedical Sciences, RMIT University, Bundoora, 3083, Australia
| | - Nathan E Hall
- Department of Animal, Plant and Soil Sciences, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Steven Bozinovski
- Chronic Infectious and Inflammatory Disease Programme, School of Health & Biomedical Sciences, RMIT University, Bundoora, 3083, Australia
| | - Eileen M Dunne
- Pneumococcal Research, Murdoch Children's Research Institute, Infection and Immunity, Parkville, 3052, Australia.,Department of Paediatrics, The University of Melbourne, Parkville, 3052, Australia
| | - Catherine Satzke
- Pneumococcal Research, Murdoch Children's Research Institute, Infection and Immunity, Parkville, 3052, Australia.,Department of Paediatrics, The University of Melbourne, Parkville, 3052, Australia.,Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Parkville, 3010, Australia
| |
Collapse
|
20
|
Kaspar J, Shields RC, Burne RA. Competence inhibition by the XrpA peptide encoded within the comX gene of Streptococcus mutans. Mol Microbiol 2018; 109:345-364. [PMID: 29802741 DOI: 10.1111/mmi.13989] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2018] [Indexed: 01/06/2023]
Abstract
Streptococcus mutans displays complex regulation of natural genetic competence. Competence development in S. mutans is controlled by a peptide derived from ComS (XIP); which along with the cytosolic regulator ComR controls the expression of the alternative sigma factor comX, the master regulator of competence development. Recently, a gene embedded within the coding region of comX was discovered and designated xrpA (comX regulatory peptide A). XrpA was found to be an antagonist of ComX, but the mechanism was not established. In this study, we reveal through both genomic and proteomic techniques that XrpA is the first described negative regulator of ComRS systems in streptococci. Transcriptomic and promoter activity assays in the ΔxrpA strain revealed an up-regulation of genes controlled by both the ComR- and ComX-regulons. An in vivo protein crosslinking and in vitro fluorescent polarization assays confirmed that the N-terminal region of XrpA were found to be sufficient in inhibiting ComR-XIP complex binding to ECom-box located within the comX promoter. This inhibitory activity was sufficient for decreases in PcomX activity, transformability and ComX accumulation. XrpA serving as a modulator of ComRS activity ultimately results in changes to subpopulation behaviors and cell fate during competence activation.
Collapse
Affiliation(s)
- Justin Kaspar
- Department of Oral Biology, University of Florida, Gainesville, FL, 32610, USA
| | - Robert C Shields
- Department of Oral Biology, University of Florida, Gainesville, FL, 32610, USA
| | - Robert A Burne
- Department of Oral Biology, University of Florida, Gainesville, FL, 32610, USA
| |
Collapse
|
21
|
ABC transporter content diversity in Streptococcus pneumoniae impacts competence regulation and bacteriocin production. Proc Natl Acad Sci U S A 2018; 115:E5776-E5785. [PMID: 29866828 PMCID: PMC6016807 DOI: 10.1073/pnas.1804668115] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The opportunistic pathogen Streptococcus pneumoniae (pneumococcus) participates in horizontal gene transfer through genetic competence and produces antimicrobial peptides called “bacteriocins.” Here, we show that the competence and bacteriocin-related ABC transporters ComAB and BlpAB share the same substrate pool, resulting in bidirectional crosstalk between competence and bacteriocin regulation. We also clarify the role of each transporter in bacteriocin secretion and show that, based on their transporter content, pneumococcal strains can be separated into a majority opportunist group that uses bacteriocins only to support competence and a minority aggressor group that uses bacteriocins in broader contexts. Our findings will impact how bacteriocin regulation and production is modeled in the many other bacterial species that use ComAB/BlpAB-type transporters. The opportunistic pathogen Streptococcus pneumoniae (pneumococcus) uses natural genetic competence to increase its adaptability through horizontal gene transfer. One method of acquiring DNA is through predation of neighboring strains with antimicrobial peptides called “bacteriocins.” Competence and production of the major family of pneumococcal bacteriocins, pneumocins, are regulated by the quorum-sensing systems com and blp, respectively. In the classical paradigm, the ABC transporters ComAB and BlpAB each secretes its own system’s signaling pheromone and in the case of BlpAB also secretes the pneumocins. While ComAB is found in all pneumococci, only 25% of strains encode an intact version of BlpAB [BlpAB(+)] while the rest do not [BlpAB(−)]. Contrary to the classical paradigm, it was previously shown that BlpAB(−) strains can activate blp through ComAB-mediated secretion of the blp pheromone during brief periods of competence. To better understand the full extent of com-blp crosstalk, we examined the contribution of each transporter to competence development and pneumocin secretion. We found that BlpAB(+) strains have a greater capacity for competence activation through BlpAB-mediated secretion of the com pheromone. Similarly, we show that ComAB and BlpAB are promiscuous and both can secrete pneumocins. Consequently, differences in pneumocin secretion between BlpAB(+) and BlpAB(−) strains derive from the regulation and kinetics of transporter expression rather than substrate specificity. We speculate that BlpAB(−) strains (opportunists) use pneumocins mainly in a narrowly tailored role for DNA acquisition and defense during competence while BlpAB(+) strains (aggressors) expand their use for the general inhibition of rival strains.
Collapse
|
22
|
A Mechanism of Unidirectional Transformation, Leading to Antibiotic Resistance, Occurs within Nasopharyngeal Pneumococcal Biofilm Consortia. mBio 2018; 9:mBio.00561-18. [PMID: 29764945 PMCID: PMC5954218 DOI: 10.1128/mbio.00561-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Streptococcus pneumoniae acquires genes for resistance to antibiotics such as streptomycin (Str) or trimethoprim (Tmp) by recombination via transformation of DNA released by other pneumococci and closely related species. Using naturally transformable pneumococci, including strain D39 serotype 2 (S2) and TIGR4 (S4), we studied whether pneumococcal nasopharyngeal transformation was symmetrical, asymmetrical, or unidirectional. Incubation of S2Tet and S4Str in a bioreactor simulating the human nasopharynx led to the generation of SpnTet/Str recombinants. Double-resistant pneumococci emerged soon after 4 h postinoculation at a recombination frequency (rF) of 2.5 × 10−4 while peaking after 8 h at a rF of 1.1 × 10−3. Acquisition of antibiotic resistance genes by transformation was confirmed by treatment with DNase I. A high-throughput serotyping method demonstrated that all double-resistant pneumococci belonged to one serotype lineage (S2Tet/Str) and therefore that unidirectional transformation had occurred. Neither heterolysis nor availability of DNA for transformation was a factor for unidirectional transformation given that the density of each strain and extracellular DNA (eDNA) released from both strains were similar. Unidirectional transformation occurred regardless of the antibiotic-resistant gene carried by donors or acquired by recipients and regardless of whether competence-stimulating peptide-receptor cross talk was allowed. Moreover, unidirectional transformation occurred when two donor strains (e.g., S4Str and S19FTmp) were incubated together, leading to S19FStr/Tmp but at a rF 3 orders of magnitude lower (4.9 × 10−6). We finally demonstrated that the mechanism leading to unidirectional transformation was due to inhibition of transformation of the donor by the recipient. Pneumococcal transformation in the human nasopharynx may lead to the acquisition of antibiotic resistance genes or genes encoding new capsular variants. Antibiotics and vaccines are currently putting pressure on a number of strains, leading to an increase in antibiotic resistance and serotype replacement. These pneumococcal strains are also acquiring virulence traits from vaccine types via transformation. In this study, we recapitulated multiple-strain colonization with strains carrying a resistance marker and selected for those acquiring resistance to two or three antibiotics, such as would occur in the human nasopharynx. Strains acquiring dual and triple resistance originated from one progenitor, demonstrating that transformation was unidirectional. Unidirectional transformation was the result of inhibition of transformation of donor strains. Unidirectional transformation has implications for the understanding of acquisition patterns of resistance determinants or capsule-switching events.
Collapse
|
23
|
Micro-scale intermixing: a requisite for stable and synergistic co-establishment in a four-species biofilm. ISME JOURNAL 2018; 12:1940-1951. [PMID: 29670216 DOI: 10.1038/s41396-018-0112-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 03/05/2018] [Accepted: 03/09/2018] [Indexed: 01/14/2023]
Abstract
Microorganisms frequently coexist in complex multispecies communities, where they distribute non-randomly, reflective of the social interactions that occur. It is therefore important to understand how social interactions and local spatial organization influences multispecies biofilm succession. Here the localization of species pairs was analyzed in three dimensions in a reproducible four-species biofilm model, to study the impact of spatial positioning of individual species on the temporal development of the community. We found, that as the biofilms developed, species pairs exhibited distinct intermixing patterns unique to the four-member biofilms. Higher biomass and more intermixing were found in four-species biofilms compared to biofilms with fewer species. Intriguingly, in local regions within the four member biofilms where Microbacterium oxydans was scant, both biomass and intermixing of all species were lowered, compared to regions where M. oxydans was present at typical densities. Our data suggest that Xanthomonas retroflexus and M. oxydans, both low abundant biofilm-members, intermixed continuously during the development of the four-species biofilm, hereby facilitating their own establishment. In turn, this seems to have promoted distinct spatial organization of Stenotrophomonas rhizophila and Paenibacillus amylolyticus enabling enhanced growth of all four species. Here local intermixing of bacteria advanced the temporal development of a multi-species biofilm.
Collapse
|
24
|
Hakansson AP, Orihuela CJ, Bogaert D. Bacterial-Host Interactions: Physiology and Pathophysiology of Respiratory Infection. Physiol Rev 2018; 98:781-811. [PMID: 29488821 PMCID: PMC5966719 DOI: 10.1152/physrev.00040.2016] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 02/06/2023] Open
Abstract
It has long been thought that respiratory infections are the direct result of acquisition of pathogenic viruses or bacteria, followed by their overgrowth, dissemination, and in some instances tissue invasion. In the last decades, it has become apparent that in contrast to this classical view, the majority of microorganisms associated with respiratory infections and inflammation are actually common members of the respiratory ecosystem and only in rare circumstances do they cause disease. This suggests that a complex interplay between host, environment, and properties of colonizing microorganisms together determines disease development and its severity. To understand the pathophysiological processes that underlie respiratory infectious diseases, it is therefore necessary to understand the host-bacterial interactions occurring at mucosal surfaces, along with the microbes inhabiting them, during symbiosis. Current knowledge regarding host-bacterial interactions during asymptomatic colonization will be discussed, including a plausible role for the human microbiome in maintaining a healthy state. With this as a starting point, we will discuss possible disruptive factors contributing to dysbiosis, which is likely to be a key trigger for pathobionts in the development and pathophysiology of respiratory diseases. Finally, from this renewed perspective, we will reflect on current and potential new approaches for treatment in the future.
Collapse
Affiliation(s)
- A P Hakansson
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University , Lund , Sweden ; Department of Microbiology, University of Alabama at Birmingham , Birmingham, Alabama ; and Center for Inflammation Research, Queens Medical Research Institute, University of Edinburgh , Edinburgh , United Kingdom
| | - C J Orihuela
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University , Lund , Sweden ; Department of Microbiology, University of Alabama at Birmingham , Birmingham, Alabama ; and Center for Inflammation Research, Queens Medical Research Institute, University of Edinburgh , Edinburgh , United Kingdom
| | - D Bogaert
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University , Lund , Sweden ; Department of Microbiology, University of Alabama at Birmingham , Birmingham, Alabama ; and Center for Inflammation Research, Queens Medical Research Institute, University of Edinburgh , Edinburgh , United Kingdom
| |
Collapse
|
25
|
Hall CW, Mah TF. Molecular mechanisms of biofilm-based antibiotic resistance and tolerance in pathogenic bacteria. FEMS Microbiol Rev 2018; 41:276-301. [PMID: 28369412 DOI: 10.1093/femsre/fux010] [Citation(s) in RCA: 845] [Impact Index Per Article: 140.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 02/22/2017] [Indexed: 02/06/2023] Open
Abstract
Biofilms are surface-attached groups of microbial cells encased in an extracellular matrix that are significantly less susceptible to antimicrobial agents than non-adherent, planktonic cells. Biofilm-based infections are, as a result, extremely difficult to cure. A wide range of molecular mechanisms contribute to the high degree of recalcitrance that is characteristic of biofilm communities. These mechanisms include, among others, interaction of antimicrobials with biofilm matrix components, reduced growth rates and the various actions of specific genetic determinants of antibiotic resistance and tolerance. Alone, each of these mechanisms only partially accounts for the increased antimicrobial recalcitrance observed in biofilms. Acting in concert, however, these defences help to ensure the survival of biofilm cells in the face of even the most aggressive antimicrobial treatment regimens. This review summarises both historical and recent scientific data in support of the known biofilm resistance and tolerance mechanisms. Additionally, suggestions for future work in the field are provided.
Collapse
|
26
|
Nesse LL, Simm R. Biofilm: A Hotspot for Emerging Bacterial Genotypes. ADVANCES IN APPLIED MICROBIOLOGY 2018; 103:223-246. [PMID: 29914658 DOI: 10.1016/bs.aambs.2018.01.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Bacteria have the ability to adapt to changing environments through rapid evolution mediated by modification of existing genetic information, as well as by horizontal gene transfer (HGT). This makes bacteria a highly successful life form when it comes to survival. Unfortunately, this genetic plasticity may result in emergence and dissemination of antimicrobial resistance and virulence genes, and even the creation of multiresistant "superbugs" which may pose serious threats to public health. As bacteria commonly reside in biofilms, there has been an increased interest in studying these phenomena within biofilms in recent years. This review summarizes the present knowledge within this important area of research. Studies on bacterial evolution in biofilms have shown that mature biofilms develop into diverse communities over time. There is growing evidence that the biofilm lifestyle may be more mutagenic than planktonic growth. Furthermore, all three main mechanisms for HGT have been observed in biofilms. This has been shown to occur both within and between bacterial species, and higher transfer rates in biofilms than in planktonic cultures were detected. Of special concern are the observations that mutants with increased antibiotic resistance occur at higher frequency in biofilms than in planktonic cultures even in the absence of antibiotic exposure. Likewise, efficient dissemination of antimicrobial resistance genes, as well as virulence genes, has been observed within the biofilm environment. This new knowledge emphasizes the importance of biofilm awareness and control.
Collapse
|
27
|
Murein Hydrolase LytF of Streptococcus sanguinis and the Ecological Consequences of Competence Development. Appl Environ Microbiol 2017; 83:AEM.01709-17. [PMID: 28986373 DOI: 10.1128/aem.01709-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/22/2017] [Indexed: 11/20/2022] Open
Abstract
The overall health of the oral cavity is dependent on proper homeostasis between health-associated bacterial colonizers and bacteria known to promote dental caries. Streptococcus sanguinis is a health-associated commensal organism, a known early colonizer of the acquired tooth pellicle, and is naturally competent. We have shown that LytF, a competence-controlled murein hydrolase, is capable of inducing the release of extracellular DNA (eDNA) from oral bacteria. Precipitated LytF and purified LytF were used as treatments against planktonic cultures and biofilms. Larger amounts of eDNA were released from cultures treated with protein samples containing LytF. Additionally, LytF could affect biofilm formation and cellular morphology. Biofilm formation was significantly decreased in the lytF-complemented strain, in which increased amounts of LytF are present. The same strain also exhibited cell morphology defects in both planktonic cultures and biofilms. Furthermore, the LytF cell morphology phenotype was reproducible in wild-type cells using purified LytF protein. In sum, our findings demonstrate that LytF can induce the release of eDNA from oral bacteria, and they suggest that, without proper regulation of LytF, cells display morphological abnormalities that contribute to biofilm malformation. In the context of the oral biofilm, LytF may play important roles as part of the competence and biofilm development programs, as well as increasing the availability of eDNA.IMPORTANCEStreptococcus sanguinis, a commensal organism in the oral cavity and one of the pioneer colonizers of the tooth surface, is associated with the overall health of the oral environment. Our laboratory showed previously that, under aerobic conditions, S. sanguinis can produce H2O2 to inhibit the growth of bacterial species that promote dental caries. This production of H2O2 by S. sanguinis also induces the release of eDNA, which is essential for proper biofilm formation. Under anaerobic conditions, S. sanguinis does not produce H2O2 but DNA is still released. Determining how S. sanguinis releases DNA is thus essential to understand biofilm formation in the oral cavity.
Collapse
|
28
|
Cooper RM, Tsimring L, Hasty J. Inter-species population dynamics enhance microbial horizontal gene transfer and spread of antibiotic resistance. eLife 2017; 6:e25950. [PMID: 29091031 PMCID: PMC5701796 DOI: 10.7554/elife.25950] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 10/10/2017] [Indexed: 01/13/2023] Open
Abstract
Horizontal gene transfer (HGT) plays a major role in the spread of antibiotic resistance. Of particular concern are Acinetobacter baumannii bacteria, which recently emerged as global pathogens, with nosocomial mortality rates reaching 19-54% (Centers for Disease Control and Prevention, 2013; Joly Guillou, 2005; Talbot et al., 2006). Acinetobacter gains antibiotic resistance remarkably rapidly (Antunes et al., 2014; Joly Guillou, 2005), with multi drug-resistance (MDR) rates exceeding 60% (Antunes et al., 2014; Centers for Disease Control and Prevention, 2013). Despite growing concern (Centers for Disease Control and Prevention, 2013; Talbot et al., 2006), the mechanisms underlying this extensive HGT remain poorly understood (Adams et al., 2008; Fournier et al., 2006; Imperi et al., 2011; Ramirez et al., 2010; Wilharm et al., 2013). Here, we show bacterial predation by Acinetobacter baylyi increases cross-species HGT by orders of magnitude, and we observe predator cells functionally acquiring adaptive resistance genes from adjacent prey. We then develop a population-dynamic model quantifying killing and HGT on solid surfaces. We show DNA released via cell lysis is readily available for HGT and may be partially protected from the environment, describe the effects of cell density, and evaluate potential environmental inhibitors. These findings establish a framework for understanding, quantifying, and combating HGT within the microbiome and the emergence of MDR super-bugs.
Collapse
Affiliation(s)
- Robert M Cooper
- BioCircuits InstituteUniversity of California, San DiegoSan DiegoUnited States
| | - Lev Tsimring
- BioCircuits InstituteUniversity of California, San DiegoSan DiegoUnited States
- San Diego Center for Systems BiologyUniversity of California, San DiegoSan DiegoUnited States
| | - Jeff Hasty
- BioCircuits InstituteUniversity of California, San DiegoSan DiegoUnited States
- San Diego Center for Systems BiologyUniversity of California, San DiegoSan DiegoUnited States
- Molecular Biology Section, Division of Biological ScienceUniversity of California, San DiegoSan DiegoUnited States
- Department of BioengineeringUniversity of California, San DiegoSan DiegoUnited States
| |
Collapse
|
29
|
Quorum sensing integrates environmental cues, cell density and cell history to control bacterial competence. Nat Commun 2017; 8:854. [PMID: 29021534 PMCID: PMC5636887 DOI: 10.1038/s41467-017-00903-y] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 08/03/2017] [Indexed: 01/08/2023] Open
Abstract
Streptococcus pneumoniae becomes competent for genetic transformation when exposed to an autoinducer peptide known as competence-stimulating peptide (CSP). This peptide was originally described as a quorum-sensing signal, enabling individual cells to regulate competence in response to population density. However, recent studies suggest that CSP may instead serve as a probe for sensing environmental cues, such as antibiotic stress or environmental diffusion. Here, we show that competence induction can be simultaneously influenced by cell density, external pH, antibiotic-induced stress, and cell history. Our experimental data is explained by a mathematical model where the environment and cell history modify the rate at which cells produce or sense CSP. Taken together, model and experiments indicate that autoinducer concentration can function as an indicator of cell density across environmental conditions, while also incorporating information on environmental factors or cell history, allowing cells to integrate cues such as antibiotic stress into their quorum-sensing response. This unifying perspective may apply to other debated quorum-sensing systems. Peptide CSP regulates natural competence in pneumococci and has been proposed as a quorum-sensing signal or a probe for sensing environmental cues. Here, the authors show that CSP levels can indeed act as an indicator of cell density and also incorporate information on environmental factors or cell history.
Collapse
|
30
|
Competitive Dominance within Biofilm Consortia Regulates the Relative Distribution of Pneumococcal Nasopharyngeal Density. Appl Environ Microbiol 2017; 83:AEM.00953-17. [PMID: 28576759 DOI: 10.1128/aem.00953-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 05/25/2017] [Indexed: 12/15/2022] Open
Abstract
Streptococcus pneumoniae is a main cause of child mortality worldwide, but strains also asymptomatically colonize the upper airways of most children and form biofilms. Recent studies have demonstrated that ∼50% of colonized children carry at least two different serotypes (i.e., strains) in the nasopharynx; however, studies of how strains coexist are limited. In this work, we investigated the physiological, genetic, and ecological requirements for the relative distribution of densities, and spatial localization, of pneumococcal strains within biofilm consortia. Biofilm consortia were prepared with vaccine type strains (i.e., serotype 6B [S6B], S19F, or S23F) and strain TIGR4 (S4). Experiments first revealed that the relative densities of S6B and S23F were similar in biofilm consortia. The density of S19F strains, however, was reduced to ∼10% in biofilm consortia, including either S6B, S23F, or TIGR4, in comparison to S19F monostrain biofilms. Reduction of S19F density within biofilm consortia was also observed in a simulated nasopharyngeal environment. Reduction of relative density was not related to growth rates, since the Malthusian parameter demonstrated similar rates of change of density for most strains. To investigate whether quorum sensing (QS) regulates relative densities in biofilm consortia, two different mutants were prepared: a TIGR4ΔluxS mutant and a TIGR4ΔcomC mutant. The density of S19F strains, however, was similarly reduced when consortia included TIGR4, TIGR4ΔluxS, or TIGR4ΔcomC Moreover, production of a different competence-stimulating peptide (CSP), CSP1 or CSP2, was not a factor that affected dominance. Finally, a mathematical model, confocal experiments, and experiments using Transwell devices demonstrated physical contact-mediated control of pneumococcal density within biofilm consortia.IMPORTANCEStreptococcus pneumoniae kills nearly half a million children every year, but it also produces nasopharyngeal biofilm consortia in a proportion of asymptomatic children, and these biofilms often contain two strains (i.e., serotypes). In our study, we investigated how strains coexist within pneumococcal consortia produced by vaccine serotypes S4, S6B, S19F, and S23F. Whereas S6B and S23F shared the biofilm consortium, our studies demonstrated reduction of the relative density of S19F strains, to ∼10% of what it would otherwise be if alone, in consortial biofilms formed with S4, S6B, or S23F. This dominance was not related to increased fitness when competing for nutrients, nor was it regulated by quorum-sensing LuxS/AI-2 or Com systems. It was demonstrated, however, to be enhanced by physical contact rather than by a product(s) secreted into the supernatant, as would naturally occur in the semidry nasopharyngeal environment. Competitive interactions within pneumococcal biofilm consortia regulate nasopharyngeal density, a risk factor for pneumococcal disease.
Collapse
|
31
|
Ibáñez de Aldecoa AL, Zafra O, González-Pastor JE. Mechanisms and Regulation of Extracellular DNA Release and Its Biological Roles in Microbial Communities. Front Microbiol 2017; 8:1390. [PMID: 28798731 PMCID: PMC5527159 DOI: 10.3389/fmicb.2017.01390] [Citation(s) in RCA: 169] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 07/10/2017] [Indexed: 12/14/2022] Open
Abstract
The capacity to release genetic material into the extracellular medium has been reported in cultures of numerous species of bacteria, archaea, and fungi, and also in the context of multicellular microbial communities such as biofilms. Moreover, extracellular DNA (eDNA) of microbial origin is widespread in natural aquatic and terrestrial environments. Different specific mechanisms are involved in eDNA release, such as autolysis and active secretion, as well as through its association with membrane vesicles. It is noteworthy that in microorganisms, in which DNA release has been studied in detail, the production of eDNA is coordinated by the population when it reaches a certain cell density, and is induced in a subpopulation in response to the accumulation of quorum sensing signals. Interestingly, in several bacteria there is also a relationship between eDNA release and the development of natural competence (the ability to take up DNA from the environment), which is also controlled by quorum sensing. Then, what is the biological function of eDNA? A common biological role has not been proposed, since different functions have been reported depending on the microorganism. However, it seems to be important in biofilm formation, can be used as a nutrient source, and could be involved in DNA damage repair and gene transfer. This review covers several aspects of eDNA research: (i) its occurrence and distribution in natural environments, (ii) the mechanisms and regulation of its release in cultured microorganisms, and (iii) its biological roles. In addition, we propose that eDNA release could be considered a social behavior, based on its quorum sensing-dependent regulation and on the described functions of eDNA in the context of microbial communities.
Collapse
Affiliation(s)
- Alejandra L Ibáñez de Aldecoa
- Laboratory of Molecular Adaptation, Department of Molecular Evolution, Centro de Astrobiología (Consejo Superior de Investigaciones Científicas/Instituto Nacional de Técnica Aeroespacial)Madrid, Spain
| | - Olga Zafra
- Experimental Sciences Faculty, Francisco de Vitoria UniversityMadrid, Spain
| | - José E González-Pastor
- Laboratory of Molecular Adaptation, Department of Molecular Evolution, Centro de Astrobiología (Consejo Superior de Investigaciones Científicas/Instituto Nacional de Técnica Aeroespacial)Madrid, Spain
| |
Collapse
|
32
|
Barenkamp SJ, Chonmaitree T, Hakansson AP, Heikkinen T, King S, Nokso-Koivisto J, Novotny LA, Patel JA, Pettigrew M, Swords WE. Panel 4: Report of the Microbiology Panel. Otolaryngol Head Neck Surg 2017; 156:S51-S62. [PMID: 28372529 PMCID: PMC5490388 DOI: 10.1177/0194599816639028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 02/24/2016] [Indexed: 12/12/2022]
Abstract
Objective To perform a comprehensive review of the literature from July 2011 until June 2015 on the virology and bacteriology of otitis media in children. Data Sources PubMed database of the National Library of Medicine. Review Methods Two subpanels comprising experts in the virology and bacteriology of otitis media were created. Each panel reviewed the relevant literature in the fields of virology and bacteriology and generated draft reviews. These initial reviews were distributed to all panel members prior to meeting together at the Post-symposium Research Conference of the 18th International Symposium on Recent Advances in Otitis Media, National Harbor, Maryland, in June 2015. A final draft was created, circulated, and approved by all panel members. Conclusions Excellent progress has been made in the past 4 years in advancing our understanding of the microbiology of otitis media. Numerous advances were made in basic laboratory studies, in animal models of otitis media, in better understanding the epidemiology of disease, and in clinical practice. Implications for Practice (1) Many viruses cause acute otitis media without bacterial coinfection, and such cases do not require antibiotic treatment. (2) When respiratory syncytial virus, metapneumovirus, and influenza virus peak in the community, practitioners can expect to see an increase in clinical otitis media cases. (3) Biomarkers that predict which children with upper respiratory tract infections will develop otitis media may be available in the future. (4) Compounds that target newly identified bacterial virulence determinants may be available as future treatment options for children with otitis media.
Collapse
Affiliation(s)
- Stephen J. Barenkamp
- Department of Pediatrics, St Louis University School of Medicine, St Louis, Missouri, USA
| | - Tasnee Chonmaitree
- Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | | | - Terho Heikkinen
- Department of Pediatrics, University of Turku and Turku University Hospital, Turku, Finland
| | - Samantha King
- The Research Institute at Nationwide Children’s Hospital and Ohio State University, Columbus, Ohio, USA
| | - Johanna Nokso-Koivisto
- Department of Otorhinolaryngology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Laura A. Novotny
- The Research Institute at Nationwide Children’s Hospital and Ohio State University, Columbus, Ohio, USA
| | - Janak A. Patel
- Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Melinda Pettigrew
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
| | - W. Edward Swords
- Department of Microbiology and Immunology, Wake Forest University, Winston-Salem, North Carolina, USA
| |
Collapse
|
33
|
Coordinated Bacteriocin Expression and Competence in Streptococcus pneumoniae Contributes to Genetic Adaptation through Neighbor Predation. PLoS Pathog 2016; 12:e1005413. [PMID: 26840124 PMCID: PMC4739721 DOI: 10.1371/journal.ppat.1005413] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 01/04/2016] [Indexed: 02/03/2023] Open
Abstract
Streptococcus pneumoniae (pneumococcus) has remained a persistent cause of invasive and mucosal disease in humans despite the widespread use of antibiotics and vaccines. The resilience of this organism is due to its capacity for adaptation through the uptake and incorporation of new genetic material from the surrounding microbial community. DNA uptake and recombination is controlled by a tightly regulated quorum sensing system that is triggered by the extracellular accumulation of competence stimulating peptide (CSP). In this study, we demonstrate that CSP can stimulate the production of a diverse array of blp bacteriocins. This cross stimulation occurs through increased production and secretion of the bacteriocin pheromone, BlpC, and requires a functional competence regulatory system. We show that a highly conserved motif in the promoter of the operon encoding BlpC and its transporter mediates the upregulation by CSP. The accumulation of BlpC following CSP stimulation results in augmented activation of the entire blp locus. Using biofilm-grown organisms as a model for competition and genetic exchange on the mucosal surface, we demonstrate that DNA exchange is enhanced by bacteriocin secretion suggesting that co-stimulation of bacteriocins with competence provides an adaptive advantage. The blp and com regulatory pathways are believed to have diverged and specialized in a remote ancestor of pneumococcus. Despite this, the two systems have maintained a regulatory connection that promotes competition and adaptation by targeting for lysis a wide array of potential competitors while simultaneously providing the means for incorporation of their DNA.
Collapse
|
34
|
Haustenne L, Bastin G, Hols P, Fontaine L. Modeling of the ComRS Signaling Pathway Reveals the Limiting Factors Controlling Competence in Streptococcus thermophilus. Front Microbiol 2015; 6:1413. [PMID: 26733960 PMCID: PMC4686606 DOI: 10.3389/fmicb.2015.01413] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 11/27/2015] [Indexed: 12/25/2022] Open
Abstract
In streptococci, entry in competence is dictated by ComX abundance. In Streptococcus thermophilus, production of ComX is transient and tightly regulated during growth: it is positively regulated by the cell-cell communication system ComRS during the activation phase and negatively regulated during the shut-off phase by unidentified late competence gene(s). Interestingly, most S. thermophilus strains are not or weakly transformable in permissive growth conditions (i.e., chemically defined medium, CDM), suggesting that some players of the ComRS regulatory pathway are limiting. Here, we combined mathematical modeling and experimental approaches to identify the components of the ComRS system which are critical for both dynamics and amplitude of ComX production in S. thermophilus. We built a deterministic, population-scaled model of the time-course regulation of specific ComX production in CDM growth conditions. Strains LMD-9 and LMG18311 were respectively selected as representative of highly and weakly transformable strains. Results from in silico simulations and in vivo luciferase activities show that ComR concentration is the main limiting factor for the level of comX expression and controls the kinetics of spontaneous competence induction in strain LMD-9. In addition, the model predicts that the poor transformability of strain LMG18311 results from a 10-fold lower comR expression level compared to strain LMD-9. In agreement, comR overexpression in both strains was shown to induce higher competence levels with deregulated kinetics patterns during growth. In conclusion, we propose that the level of ComR production is one important factor that could explain competence heterogeneity among S. thermophilus strains.
Collapse
Affiliation(s)
- Laurie Haustenne
- Biochimie, Biophysique et Génétique des Microorganismes, Institut des Sciences de la Vie, Université catholique de Louvain Louvain-la-Neuve, Belgium
| | - Georges Bastin
- Center for Systems Engineering and Applied Mechanics, ICTEAM, Université catholique de Louvain Louvain-la-Neuve, Belgium
| | - Pascal Hols
- Biochimie, Biophysique et Génétique des Microorganismes, Institut des Sciences de la Vie, Université catholique de Louvain Louvain-la-Neuve, Belgium
| | - Laetitia Fontaine
- Biochimie, Biophysique et Génétique des Microorganismes, Institut des Sciences de la Vie, Université catholique de Louvain Louvain-la-Neuve, Belgium
| |
Collapse
|
35
|
Domenech M, Ruiz S, Moscoso M, García E. In vitro biofilm development of Streptococcus pneumoniae and formation of choline-binding protein-DNA complexes. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:715-727. [PMID: 25950767 DOI: 10.1111/1758-2229.12295] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 04/08/2015] [Indexed: 06/04/2023]
Abstract
Extracellular deoxyribonucleic acid (eDNA) is an essential component of bacterial biofilm matrices, and is required in their formation and maintenance. Extracellular DNA binds to exopolysaccharides or extracellular proteins, affording biofilms greater structural integrity. Recently, we reported evidence of intercellular eDNA-LytC complexes in pneumococcal biofilms. The LytC lysozyme is a member of the choline-binding family of proteins (CBPs) located on the pneumococcal surface. The present work shows that other CBPs, i.e. LytA, LytB, Pce, PspC and CbpF, which have a pI between 5 and 6, can bind DNA in vitro. This process requires the presence of divalent cations other than Mg(2+). This DNA binding capacity of CBPs appears to be independent of their enzymatic activity and, at least in the case of LytA, does not require the choline-binding domain characteristic of CBPs. Positively charged, surface-exposed, 25 amino acid-long peptides derived from the catalytic domain of LytB, were also found capable of DNA binding through electrostatic interactions. Confocal laser scanning microcopy revealed the existence of cell-associated LytB-eDNA complexes in Streptococcus pneumoniae biofilms. These and other findings suggest that these surface-located proteins of S. pneumoniae could play roles of varying importance in the colonization and/or invasion of human host where different environmental conditions exist.
Collapse
Affiliation(s)
- Mirian Domenech
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (CIB-CSIC), Madrid, 28040, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Susana Ruiz
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Miriam Moscoso
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (CIB-CSIC), Madrid, 28040, Spain
| | - Ernesto García
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (CIB-CSIC), Madrid, 28040, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| |
Collapse
|
36
|
Minimal Peptidoglycan (PG) Turnover in Wild-Type and PG Hydrolase and Cell Division Mutants of Streptococcus pneumoniae D39 Growing Planktonically and in Host-Relevant Biofilms. J Bacteriol 2015; 197:3472-85. [PMID: 26303829 DOI: 10.1128/jb.00541-15] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 08/15/2015] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED We determined whether there is turnover of the peptidoglycan (PG) cell wall of the ovococcus bacterial pathogen Streptococcus pneumoniae (pneumococcus). Pulse-chase experiments on serotype 2 strain D39 radiolabeled with N-acetylglucosamine revealed little turnover and release of PG breakdown products during growth compared to published reports of PG turnover in Bacillus subtilis. PG dynamics were visualized directly by long-pulse-chase-new-labeling experiments using two colors of fluorescent d-amino acid (FDAA) probes to microscopically detect regions of new PG synthesis. Consistent with minimal PG turnover, hemispherical regions of stable "old" PG persisted in D39 and TIGR4 (serotype 4) cells grown in rich brain heart infusion broth, in D39 cells grown in chemically defined medium containing glucose or galactose as the carbon source, and in D39 cells grown as biofilms on a layer of fixed human epithelial cells. In contrast, B. subtilis exhibited rapid sidewall PG turnover in similar FDAA-labeling experiments. High-performance liquid chromatography (HPLC) analysis of biochemically released peptides from S. pneumoniae PG validated that FDAAs incorporated at low levels into pentamer PG peptides and did not change the overall composition of PG peptides. PG dynamics were also visualized in mutants lacking PG hydrolases that mediate PG remodeling, cell separation, or autolysis and in cells lacking the MapZ and DivIVA division regulators. In all cases, hemispheres of stable old PG were maintained. In PG hydrolase mutants exhibiting aberrant division plane placement, FDAA labeling revealed patches of inert PG at turns and bulge points. We conclude that growing S. pneumoniae cells exhibit minimal PG turnover compared to the PG turnover in rod-shaped cells. IMPORTANCE PG cell walls are unique to eubacteria, and many bacterial species turn over and recycle their PG during growth, stress, colonization, and virulence. Consequently, PG breakdown products serve as signals for bacteria to induce antibiotic resistance and as activators of innate immune responses. S. pneumoniae is a commensal bacterium that colonizes the human nasopharynx and opportunistically causes serious respiratory and invasive diseases. The results presented here demonstrate a distinct demarcation between regions of old PG and regions of new PG synthesis and minimal turnover of PG in S. pneumoniae cells growing in culture or in host-relevant biofilms. These findings suggest that S. pneumoniae minimizes the release of PG breakdown products by turnover, which may contribute to evasion of the innate immune system.
Collapse
|
37
|
Kaspar J, Ahn SJ, Palmer SR, Choi SC, Stanhope MJ, Burne RA. A unique open reading frame within the comX gene of Streptococcus mutans regulates genetic competence and oxidative stress tolerance. Mol Microbiol 2015; 96:463-82. [PMID: 25620525 DOI: 10.1111/mmi.12948] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2015] [Indexed: 01/19/2023]
Abstract
Streptococcus mutans displays complex regulation of genetic competence, with ComX controlling late competence gene transcription. The rcrRPQ operon has been shown to link oxidative stress tolerance, (p)ppGpp metabolism and competence in S. mutans. Importantly, an rcrR polar (ΔrcrR-P) mutant is hyper-transformable, but an rcrR non-polar (ΔrcrR-NP) mutant cannot be transformed. Transcriptome comparisons of the rcrR mutants using RNA-Seq and quantitative real-time polymerase chain reaction revealed little expression in the 5' region of comX in ΔrcrR-NP, but high level expression in the 3' region. Northern blotting with comX probes revealed two distinct transcripts in the ΔrcrR-P and ΔrcrR-NP strains, and 5' Rapid Amplification of cDNA Ends mapped the 5' terminus of the shorter transcript to nt +140 of the comX structural gene, where a unique 69-aa open reading frame, termed XrpA, was encoded in a different reading frame than ComX. Two single-nucleotide substitution mutants (comX::T162C; comX::T210A) were introduced to disrupt XrpA without affecting the sequence of ComX. When the mutations were in the ΔrcrR-NP genetic background, ComX production and transformation were restored. Overexpression of xrpA led to impaired growth in aerobic conditions and decreased transformability. These results reveal an unprecedented mechanism for competence regulation and stress tolerance by a gene product encoded within the comX gene that appears unique to S. mutans.
Collapse
Affiliation(s)
- Justin Kaspar
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, 32610, USA
| | | | | | | | | | | |
Collapse
|
38
|
Die for the community: an overview of programmed cell death in bacteria. Cell Death Dis 2015; 6:e1609. [PMID: 25611384 PMCID: PMC4669768 DOI: 10.1038/cddis.2014.570] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 11/25/2014] [Accepted: 12/01/2014] [Indexed: 02/07/2023]
Abstract
Programmed cell death is a process known to have a crucial role in many aspects of eukaryotes physiology and is clearly essential to their life. As a consequence, the underlying molecular mechanisms have been extensively studied in eukaryotes and we now know that different signalling pathways leading to functionally and morphologically different forms of death exist in these organisms. Similarly, mono-cellular organism can activate signalling pathways leading to death of a number of cells within a colony. The reason why a single-cell organism would activate a program leading to its death is apparently counterintuitive and probably for this reason cell death in prokaryotes has received a lot less attention in the past years. However, as summarized in this review there are many reasons leading to prokaryotic cell death, for the benefit of the colony. Indeed, single-celled organism can greatly benefit from multicellular organization. Within this forms of organization, regulation of death becomes an important issue, contributing to important processes such as: stress response, development, genetic transformation, and biofilm formation.
Collapse
|
39
|
Chao Y, Marks LR, Pettigrew MM, Hakansson AP. Streptococcus pneumoniae biofilm formation and dispersion during colonization and disease. Front Cell Infect Microbiol 2015; 4:194. [PMID: 25629011 PMCID: PMC4292784 DOI: 10.3389/fcimb.2014.00194] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 12/24/2014] [Indexed: 02/06/2023] Open
Abstract
Streptococcus pneumoniae (the pneumococcus) is a common colonizer of the human nasopharynx. Despite a low rate of invasive disease, the high prevalence of colonization results in millions of infections and over one million deaths per year, mostly in individuals under the age of 5 and the elderly. Colonizing pneumococci form well-organized biofilm communities in the nasopharyngeal environment, but the specific role of biofilms and their interaction with the host during colonization and disease is not yet clear. Pneumococci in biofilms are highly resistant to antimicrobial agents and this phenotype can be recapitulated when pneumococci are grown on respiratory epithelial cells under conditions found in the nasopharyngeal environment. Pneumococcal biofilms display lower levels of virulence in vivo and provide an optimal environment for increased genetic exchange both in vitro and in vivo, with increased natural transformation seen during co-colonization with multiple strains. Biofilms have also been detected on mucosal surfaces during pneumonia and middle ear infection, although the role of these biofilms in the disease process is debated. Recent studies have shown that changes in the nasopharyngeal environment caused by concomitant virus infection, changes in the microflora, inflammation, or other host assaults trigger active release of pneumococci from biofilms. These dispersed bacteria have distinct phenotypic properties and transcriptional profiles different from both biofilm and broth-grown, planktonic bacteria, resulting in a significantly increased virulence in vivo. In this review we discuss the properties of pneumococcal biofilms, the role of biofilm formation during pneumococcal colonization, including their propensity for increased ability to exchange genetic material, as well as mechanisms involved in transition from asymptomatic biofilm colonization to dissemination and disease of otherwise sterile sites. Greater understanding of pneumococcal biofilm formation and dispersion will elucidate novel avenues to interfere with the spread of antibiotic resistance and vaccine escape, as well as novel strategies to target the mechanisms involved in induction of pneumococcal disease.
Collapse
Affiliation(s)
- Yashuan Chao
- Division of Experimental Infection Medicine, Department of Laboratory Medicine, Lund UniversityMalmö, Sweden
| | - Laura R. Marks
- Department of Microbiology and Immunology, University at Buffalo, The State University of New YorkBuffalo, NY, USA
| | - Melinda M. Pettigrew
- Department of Epidemiology and Microbial Diseases, Yale School of Public HealthNew Haven, CT, USA
| | - Anders P. Hakansson
- Division of Experimental Infection Medicine, Department of Laboratory Medicine, Lund UniversityMalmö, Sweden
- Department of Microbiology and Immunology, University at Buffalo, The State University of New YorkBuffalo, NY, USA
| |
Collapse
|
40
|
Jack AA, Daniels DE, Jepson MA, Vickerman MM, Lamont RJ, Jenkinson HF, Nobbs AH. Streptococcus gordonii comCDE (competence) operon modulates biofilm formation with Candida albicans. MICROBIOLOGY-SGM 2014; 161:411-421. [PMID: 25505189 DOI: 10.1099/mic.0.000010] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Candida albicans is a pleiomorphic fungus that forms mixed species biofilms with Streptococcus gordonii, an early colonizer of oral cavity surfaces. Activation of quorum sensing (QS; intercellular signalling) promotes monospecies biofilm development by these micro-organisms, but the role of QS in mixed species communities is not understood. The comCDE genes in S. gordonii encode a sensor-regulator system (ComDE), which is activated by the comC gene product (CSP, competence stimulating peptide) and modulates expression of QS-regulated genes. Dual species biofilms of S. gordonii ΔcomCDE or ΔcomC mutants with C. albicans showed increased biomass compared to biofilms of S. gordonii DL1 wild-type with C. albicans. The ΔcomCDE mutant dual species biofilms in particular contained more extracellular DNA (eDNA), and could be dispersed with DNase I or protease treatment. Exogenous CSP complemented the S. gordonii ΔcomC transformation deficiency, as well as the ΔcomC-C. albicans biofilm phenotype. Purified CSP did not affect C. albicans hyphal filament formation but inhibited monospecies biofilm formation by C. albicans. The results suggest that the S. gordonii comCDE QS-system modulates the production of eDNA and the incorporation of C. albicans into dual species biofilms.
Collapse
Affiliation(s)
- Alison A Jack
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, UK
| | - Debbie E Daniels
- School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, UK.,School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, UK
| | - Mark A Jepson
- School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - M Margaret Vickerman
- Department of Oral Biology, University at Buffalo, 223 Foster Hall, Buffalo, NY 14214, USA
| | - Richard J Lamont
- Center for Oral Health and Systemic Disease, University of Louisville School of Dentistry, 501 South Preston Street, Louisville, KY 40202, USA
| | - Howard F Jenkinson
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, UK
| | - Angela H Nobbs
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, UK
| |
Collapse
|
41
|
Straume D, Stamsås GA, Håvarstein LS. Natural transformation and genome evolution in Streptococcus pneumoniae. INFECTION GENETICS AND EVOLUTION 2014; 33:371-80. [PMID: 25445643 DOI: 10.1016/j.meegid.2014.10.020] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 10/16/2014] [Accepted: 10/23/2014] [Indexed: 01/30/2023]
Abstract
Streptococcus pneumoniae is a frequent colonizer of the human nasopharynx that has the potential to cause severe infections such as pneumonia, bacteremia and meningitis. Despite considerable efforts to reduce the burden of pneumococcal disease, it continues to be a major public health problem. After the Second World War, antimicrobial therapy was introduced to fight pneumococcal infections, followed by the first effective vaccines more than half a century later. These clinical interventions generated a selection pressure that drove the evolution of vaccine-escape mutants and strains that were highly resistant against antibiotics. The remarkable ability of S. pneumoniae to acquire drug resistance and evade vaccine pressure is due to its recombination-mediated genetic plasticity. S. pneumoniae is competent for natural genetic transformation, a property that enables the pneumococcus to acquire new traits by taking up naked DNA from the environment and incorporating it into its genome through homologous recombination. In the present paper, we review current knowledge on pneumococcal transformation, and discuss how the pneumococcus uses this mechanism to adapt and survive under adverse and fluctuating conditions.
Collapse
Affiliation(s)
- Daniel Straume
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, NO-1432 Ås, Norway
| | - Gro Anita Stamsås
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, NO-1432 Ås, Norway
| | - Leiv Sigve Håvarstein
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, NO-1432 Ås, Norway.
| |
Collapse
|
42
|
Sztajer H, Szafranski SP, Tomasch J, Reck M, Nimtz M, Rohde M, Wagner-Döbler I. Cross-feeding and interkingdom communication in dual-species biofilms of Streptococcus mutans and Candida albicans. THE ISME JOURNAL 2014; 8:2256-71. [PMID: 24824668 PMCID: PMC4992082 DOI: 10.1038/ismej.2014.73] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 03/27/2014] [Accepted: 03/28/2014] [Indexed: 01/30/2023]
Abstract
Polymicrobial biofilms are of large medical importance, but relatively little is known about the role of interspecies interactions for their physiology and virulence. Here, we studied two human pathogens co-occuring in the oral cavity, the opportunistic fungus Candida albicans and the caries-promoting bacterium Streptococcus mutans. Dual-species biofilms reached higher biomass and cell numbers than mono-species biofilms, and the production of extracellular polymeric substances (EPSs) by S. mutans was strongly suppressed, which was confirmed by scanning electron microscopy, gas chromatography-mass spectrometry and transcriptome analysis. To detect interkingdom communication, C. albicans was co-cultivated with a strain of S. mutans carrying a transcriptional fusion between a green fluorescent protein-encoding gene and the promoter for sigX, the alternative sigma factor of S. mutans, which is induced by quorum sensing signals. Strong induction of sigX was observed in dual-species biofilms, but not in single-species biofilms. Conditioned media from mixed biofilms but not from C. albicans or S. mutans cultivated alone activated sigX in the reporter strain. Deletion of comS encoding the synthesis of the sigX-inducing peptide precursor abolished this activity, whereas deletion of comC encoding the competence-stimulating peptide precursor had no effect. Transcriptome analysis of S. mutans confirmed induction of comS, sigX, bacteriocins and the downstream late competence genes, including fratricins, in dual-species biofilms. We show here for the first time the stimulation of the complete quorum sensing system of S. mutans by a species from another kingdom, namely the fungus C. albicans, resulting in fundamentally changed virulence properties of the caries pathogen.
Collapse
Affiliation(s)
- Helena Sztajer
- Research Group Microbial Communication, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Szymon P Szafranski
- Research Group Microbial Communication, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Jürgen Tomasch
- Research Group Microbial Communication, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Michael Reck
- Research Group Microbial Communication, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Manfred Nimtz
- Research Group Proteomics, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Irene Wagner-Döbler
- Research Group Microbial Communication, Helmholtz Centre for Infection Research, Braunschweig, Germany
| |
Collapse
|
43
|
Jimenez JC, Federle MJ. Quorum sensing in group A Streptococcus. Front Cell Infect Microbiol 2014; 4:127. [PMID: 25309879 PMCID: PMC4162386 DOI: 10.3389/fcimb.2014.00127] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 08/26/2014] [Indexed: 01/05/2023] Open
Abstract
Quorum sensing (QS) is a widespread phenomenon in the microbial world that has important implications in the coordination of population-wide responses in several bacterial pathogens. In Group A Streptococcus (GAS), many questions surrounding QS systems remain to be solved pertaining to their function and their contribution to the GAS lifestyle in the host. The QS systems of GAS described to date can be categorized into four groups: regulator gene of glucosyltransferase (Rgg), Sil, lantibiotic systems, and LuxS/AI-2. The Rgg family of proteins, a conserved group of transcription factors that modify their activity in response to signaling peptides, has been shown to regulate genes involved in virulence, biofilm formation and competence. The sil locus, whose expression is regulated by the activity of signaling peptides and a putative two-component system (TCS), has been implicated on regulating genes involved with invasive disease in GAS isolates. Lantibiotic regulatory systems are involved in the production of bacteriocins and their autoregulation, and some of these genes have been shown to target both bacterial organisms as well as processes of survival inside the infected host. Finally AI-2 (dihydroxy pentanedione, DPD), synthesized by the LuxS enzyme in several bacteria including GAS, has been proposed to be a universal bacterial communication molecule. In this review we discuss the mechanisms of these four systems, the putative functions of their targets, and pose critical questions for future studies.
Collapse
Affiliation(s)
- Juan Cristobal Jimenez
- Department of Microbiology and Immunology, College of Medicine, University of Illinois at Chicago Chicago, IL, USA
| | - Michael J Federle
- Department of Medicinal Chemistry and Pharmacognosy, Center for Pharmaceutical Biotechnology, College of Pharmacy, University of Illinois at Chicago Chicago, IL, USA
| |
Collapse
|
44
|
Roberts AP, Kreth J. The impact of horizontal gene transfer on the adaptive ability of the human oral microbiome. Front Cell Infect Microbiol 2014; 4:124. [PMID: 25250243 PMCID: PMC4157583 DOI: 10.3389/fcimb.2014.00124] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 08/19/2014] [Indexed: 02/06/2023] Open
Abstract
The oral microbiome is composed of a multitude of different species of bacteria, each capable of occupying one or more of the many different niches found within the human oral cavity. This community exhibits many types of complex interactions which enable it to colonize and rapidly respond to changes in the environment in which they live. One of these interactions is the transfer, or acquisition, of DNA within this environment, either from co-resident bacterial species or from exogenous sources. Horizontal gene transfer in the oral cavity gives some of the resident bacteria the opportunity to sample a truly enormous metagenome affording them considerable adaptive potential which may be key to survival in such a varying environment. In this review the underlying mechanisms of HGT are discussed in relation to the oral microbiome with numerous examples described where the direct acquisition of exogenous DNA has contributed to the fitness of the bacterial host within the human oral cavity.
Collapse
Affiliation(s)
- Adam P Roberts
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College London London, UK
| | - Jens Kreth
- Department of Microbiology and Immunology, College of Medicine, University of Oklahoma Health Sciences Center Oklahoma City, OK, USA
| |
Collapse
|
45
|
Carrolo M, Pinto FR, Melo-Cristino J, Ramirez M. Pherotype influences biofilm growth and recombination in Streptococcus pneumoniae. PLoS One 2014; 9:e92138. [PMID: 24646937 PMCID: PMC3960169 DOI: 10.1371/journal.pone.0092138] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 02/17/2014] [Indexed: 01/01/2023] Open
Abstract
In Streptococcus pneumoniae the competence-stimulating peptide (CSP), encoded by the comC gene, controls competence development and influences biofilm growth. We explored the influence of pherotype, defined by the two major comC allelic variants (comC1 and comC2), on biofilm development and recombination efficiency. Among isolates recovered from human infections those presenting comC1 show a higher capacity to form in vitro biofilms. The influence of pherotype on biofilm growth was confirmed by experiments with isogenic strains differing in their comC alleles. Biofilm architecture evaluated by confocal laser scanning microscopy showed that strains carrying comC1 form biofilms that are denser and thicker than those carrying the comC2 allele. Isogenic strains carrying the comC1 allele yielded more transformants than those carrying the comC2 allele in both planktonic and biofilm growth. Transformation assays with comC knockout strains show that ComD1 needs lower doses of the signaling peptide to reach the same biological outcomes. In contrast to mixed planktonic growth, within mixed biofilms inter-pherotype genetic exchange is less frequent than that occurring between bacteria of the same pherotype. Since biofilms are a major bacterial lifestyle, these observations may explain the genetic differentiation between populations with different pherotypes reported previously. Considering that biofilms have been associated with colonization our results suggest that strains carrying the comC1 allele may be more transmissible and more efficient at persisting in carriage. Both effects may help explain the higher prevalence of the comC1 allele in the pneumococcal population.
Collapse
Affiliation(s)
- Margarida Carrolo
- Instituto de Microbiologia, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | | | - José Melo-Cristino
- Instituto de Microbiologia, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Mário Ramirez
- Instituto de Microbiologia, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- * E-mail:
| |
Collapse
|
46
|
Chewapreecha C, Harris SR, Croucher NJ, Turner C, Marttinen P, Cheng L, Pessia A, Aanensen DM, Mather AE, Page AJ, Salter SJ, Harris D, Nosten F, Goldblatt D, Corander J, Parkhill J, Turner P, Bentley SD. Dense genomic sampling identifies highways of pneumococcal recombination. Nat Genet 2014; 46:305-309. [PMID: 24509479 PMCID: PMC3970364 DOI: 10.1038/ng.2895] [Citation(s) in RCA: 271] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Accepted: 01/15/2014] [Indexed: 11/24/2022]
Abstract
Evasion of clinical interventions by Streptococcus pneumoniae occurs through selection of non-susceptible genomic variants. We report whole-genome sequencing of 3,085 pneumococcal carriage isolates from a 2.4-km(2) refugee camp. This sequencing provides unprecedented resolution of the process of recombination and its impact on population evolution. Genomic recombination hotspots show remarkable consistency between lineages, indicating common selective pressures acting at certain loci, particularly those associated with antibiotic resistance. Temporal changes in antibiotic consumption are reflected in changes in recombination trends, demonstrating rapid spread of resistance when selective pressure is high. The highest frequencies of receipt and donation of recombined DNA fragments were observed in non-encapsulated lineages, implying that this largely overlooked pneumococcal group, which is beyond the reach of current vaccines, may have a major role in genetic exchange and the adaptation of the species as a whole. These findings advance understanding of pneumococcal population dynamics and provide information for the design of future intervention strategies.
Collapse
Affiliation(s)
- Claire Chewapreecha
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Simon R Harris
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Nicholas J Croucher
- Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Hospital, London, W2 1PG, UK
| | - Claudia Turner
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Maesot 63110, Thailand
- Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7LJ, UK
| | - Pekka Marttinen
- Helsinki Institute for Information Technology HIIT, Department of Information and Computer Science, Aalto University, 00076, Finland
| | - Lu Cheng
- Department of Mathematics and Statistics, University of Helsinki, 00014, Finland
| | - Alberto Pessia
- Department of Mathematics and Statistics, University of Helsinki, 00014, Finland
| | - David M Aanensen
- Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Hospital, London, W2 1PG, UK
| | - Alison E Mather
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Andrew J Page
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Susannah J. Salter
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - David Harris
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Francois Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Maesot 63110, Thailand
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7LJ, UK
| | - David Goldblatt
- Immunobiology Unit, Institute of Child Health, University College London, WC1N 1EH, UK
| | - Jukka Corander
- Department of Mathematics and Statistics, University of Helsinki, 00014, Finland
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, CB2 0QQ, UK
| | - Julian Parkhill
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Paul Turner
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Maesot 63110, Thailand
- Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7LJ, UK
| | - Stephen D Bentley
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, CB2 0QQ, UK
| |
Collapse
|
47
|
|
48
|
Hakansson AP. Pneumococcal Adaptive Responses to Changing Host Environments. J Infect Dis 2014; 210:1-3. [DOI: 10.1093/infdis/jiu084] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
49
|
Johnston C, Campo N, Bergé MJ, Polard P, Claverys JP. Streptococcus pneumoniae, le transformiste. Trends Microbiol 2014; 22:113-9. [PMID: 24508048 DOI: 10.1016/j.tim.2014.01.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 01/09/2014] [Accepted: 01/09/2014] [Indexed: 10/25/2022]
Abstract
Streptococcus pneumoniae (the pneumococcus) is an important human pathogen. Natural genetic transformation, which was discovered in this species, involves internalization of exogenous single-stranded DNA and its incorporation into the chromosome. It allows acquisition of pathogenicity islands and antibiotic resistance and promotes vaccine escape via capsule switching. This opinion article discusses how recent advances regarding several facets of pneumococcal transformation support the view that the process has evolved to maximize plasticity potential in this species, making the pneumococcus le transformiste of the bacterial kingdom and providing an advantage in the constant struggle between this pathogen and its host.
Collapse
Affiliation(s)
- Calum Johnston
- Centre National de la Recherche Scientifique, LMGM-UMR5100, F-31000 Toulouse, France; Université de Toulouse, UPS, Laboratoire de Microbiologie et Génétique Moléculaires, F-31000 Toulouse, France
| | - Nathalie Campo
- Centre National de la Recherche Scientifique, LMGM-UMR5100, F-31000 Toulouse, France; Université de Toulouse, UPS, Laboratoire de Microbiologie et Génétique Moléculaires, F-31000 Toulouse, France
| | - Matthieu J Bergé
- Centre National de la Recherche Scientifique, LMGM-UMR5100, F-31000 Toulouse, France; Université de Toulouse, UPS, Laboratoire de Microbiologie et Génétique Moléculaires, F-31000 Toulouse, France
| | - Patrice Polard
- Centre National de la Recherche Scientifique, LMGM-UMR5100, F-31000 Toulouse, France; Université de Toulouse, UPS, Laboratoire de Microbiologie et Génétique Moléculaires, F-31000 Toulouse, France
| | - Jean-Pierre Claverys
- Centre National de la Recherche Scientifique, LMGM-UMR5100, F-31000 Toulouse, France; Université de Toulouse, UPS, Laboratoire de Microbiologie et Génétique Moléculaires, F-31000 Toulouse, France.
| |
Collapse
|
50
|
Dufour D, Lévesque CM. Bacterial behaviors associated with the quorum-sensing peptide pheromone ('alarmone') in streptococci. Future Microbiol 2013; 8:593-605. [PMID: 23642115 DOI: 10.2217/fmb.13.23] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Streptococci are among the predominant bacterial species living in the human body. They are normally harmless bacteria, but have the ability to cause diverse infections, ranging from mild (e.g., tooth decay and sore throat) to life-threatening (e.g., endocarditis and meningitis). Streptococci have evolved various means of coping with the deleterious effects of environmental stressors and avoiding the host immune system. Recently, several studies have shown that streptococci colonizing the mouth and upper respiratory tract are able to mount complex stress responses in order to persist and successfully survive competition in their ecological niche. Using a small quorum-sensing peptide pheromone acting as a stress-inducible 'alarmone', oral streptococci synchronize the gene expression of a specific group of cells to coordinate important biological activities.
Collapse
Affiliation(s)
- Delphine Dufour
- Dental Research Institute, Faculty of Dentistry, University of Toronto, 124 Edward St, Room 454B, Toronto, ON, M5G 1G6, Canada
| | | |
Collapse
|