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Mårli MT, Oppegaard O, Porcellato D, Straume D, Kjos M. Genetic modification of Streptococcus dysgalactiae by natural transformation. mSphere 2024:e0021424. [PMID: 38904369 DOI: 10.1128/msphere.00214-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 05/13/2024] [Indexed: 06/22/2024] Open
Abstract
Streptococcus dysgalactiae is an emerging human and animal pathogen. Functional studies of genes involved in virulence of S. dysgalactiae and other pyogenic group streptococci are often hampered by limited genetic tractability. It is known that pyogenic streptococci carry genes required for competence for natural transformation; however, in contrast to other streptococcal subgroups, there is limited evidence for gene transfer by natural transformation in these bacteria. In this study, we systematically assessed the genomes of 179 S. dysgalactiae strains of both human and animal origins (subsp. equisimilis and dysgalactiae, respectively) for the presence of genes required for natural transformation. While a considerable fraction of the strains contained inactive genes, the majority (64.2%) of the strains had an intact gene set. In selected strains, we examined the dynamics of competence activation after addition of competence-inducing pheromones using transcriptional reporter assays and exploratory RNA-seq. Based on these findings, we were able to establish a protocol allowing us to utilize natural transformation to construct deletion mutants by allelic exchange in several S. dysgalactiae strains of both subspecies. As part of the work, we deleted putative lactose utilization genes to study their role in growth on lactose. The data presented here provide new knowledge on the potential of horizonal gene transfer by natural transformation in S. dysgalactiae and, importantly, demonstrates the possibility to exploit natural transformation for genetic engineering in these bacteria. IMPORTANCE Numerous Streptococcus spp. exchange genes horizontally through natural transformation, which also facilitates efficient genetic engineering in these organisms. However, for the pyogenic group of streptococci, including the emerging pathogen Streptococcus dysgalactiae, there is limited experimental evidence for natural transformation. In this study, we demonstrate that natural transformation in vitro indeed is possible in S. dysgalactiae strains under optimal conditions. We utilized this method to perform gene deletion through allelic exchange in several strains, thereby paving the way for more efficient gene engineering methods in pyogenic streptococci.
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Affiliation(s)
- Marita Torrissen Mårli
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Oddvar Oppegaard
- Haukeland University Hospital, University of Bergen, Bergen, Norway
| | - Davide Porcellato
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Daniel Straume
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Morten Kjos
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
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Brasino M, Wagnell E, Ozdemir ES, Ranganathan S, Merritt J. Mutation of the peptide-regulated transcription factor ComR for amidated peptide specificity and heterologous function in Lactiplantibacillus plantarum WCFS1. Microbiol Spectr 2024; 12:e0051724. [PMID: 38687019 DOI: 10.1128/spectrum.00517-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 03/28/2024] [Indexed: 05/02/2024] Open
Abstract
There is a growing interest in the use of probiotic bacteria as biosensors for the detection of disease. However, there is a lack of bacterial receptors developed for specific disease biomarkers. Here, we have investigated the use of the peptide-regulated transcription factor ComR from Streptococcus spp. for specific peptide biomarker detection. ComR exhibits a number of attractive features that are potentially exploitable to create a biomolecular switch for engineered biosensor circuitry within the probiotic organism Lactiplantibacillus plantarum WCFS1. Through iterative design-build-test cycles, we developed a genomically integrated, ComR-based biosensor circuit that allowed WCFS1 to detect low nanomolar concentrations of ComR's cognate peptide XIP. By screening a library of ComR proteins with mutant residues substituted at the K100 position, we identified mutations that increased the specificity of ComR toward an amidated version of its cognate peptide, demonstrating the potential for ComR to detect this important class of biomarker.IMPORTANCEUsing bacteria to detect disease is an exciting possibility under active study. Detecting extracellular peptides with specific amino acid sequences would be particularly useful as these are important markers of health and disease (biomarkers). In this work, we show that a probiotic bacteria (Lactiplantibacillus plantarum) can be genetically engineered to detect specific extracellular peptides using the protein ComR from Streptococcus bacteria. In its natural form, ComR allowed the probiotic bacteria to detect a specific peptide, XIP. We then modified XIP to be more like the peptide biomarkers found in humans and engineered ComR so that it activated with this modified XIP and not the original XIP. This newly engineered ComR also worked in the probiotic bacteria, as expected. This suggests that with additional engineering, ComR might be able to activate with human peptide biomarkers and be used by genetically engineered probiotic bacteria to better detect disease.
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Affiliation(s)
- Michael Brasino
- Cancer Early Detection Advanced Research (CEDAR) Center, Knight Cancer Institute, School of Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - Eli Wagnell
- Cancer Early Detection Advanced Research (CEDAR) Center, Knight Cancer Institute, School of Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - E Sila Ozdemir
- Cancer Early Detection Advanced Research (CEDAR) Center, Knight Cancer Institute, School of Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - Srivathsan Ranganathan
- Cancer Early Detection Advanced Research (CEDAR) Center, Knight Cancer Institute, School of Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - Justin Merritt
- Department of Biomaterial and Biomedical Sciences, School of Dentistry, Oregon Health and Science University, Portland, Oregon, USA
- Department of Molecular Microbiology and Immunology, School of Medicine, Oregon Health and Science University, Portland, Oregon, USA
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Pettersen JS, Nielsen FD, Andreassen PR, Møller-Jensen J, Jørgensen M. A comprehensive analysis of pneumococcal two-component system regulatory networks. NAR Genom Bioinform 2024; 6:lqae039. [PMID: 38650915 PMCID: PMC11034029 DOI: 10.1093/nargab/lqae039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 04/04/2024] [Accepted: 04/12/2024] [Indexed: 04/25/2024] Open
Abstract
Two-component systems are key signal-transduction systems that enable bacteria to respond to a wide variety of environmental stimuli. The human pathogen, Streptococcus pneumoniae (pneumococcus) encodes 13 two-component systems and a single orphan response regulator, most of which are significant for pneumococcal pathogenicity. Mapping the regulatory networks governed by these systems is key to understand pneumococcal host adaptation. Here we employ a novel bioinformatic approach to predict the regulons of each two-component system based on publicly available whole-genome sequencing data. By employing pangenome-wide association studies (panGWAS) to predict genotype-genotype associations for each two-component system, we predicted regulon genes of 11 of the pneumococcal two-component systems. Through validation via next-generation RNA-sequencing on response regulator overexpression mutants, several top candidate genes predicted by the panGWAS analysis were confirmed as regulon genes. The present study presents novel details on multiple pneumococcal two-component systems, including an expansion of regulons, identification of candidate response regulator binding motifs, and identification of candidate response regulator-regulated small non-coding RNAs. We also demonstrate a use for panGWAS as a complementary tool in target gene identification via identification of genotype-to-genotype links. Expanding our knowledge on two-component systems in pathogens is crucial to understanding how these bacteria sense and respond to their host environment, which could prove useful in future drug development.
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Affiliation(s)
- Jens Sivkær Pettersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Flemming Damgaard Nielsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
- Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark
| | | | - Jakob Møller-Jensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Mikkel Girke Jørgensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
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Guo M, Renshaw CP, Mull RW, Tal-Gan Y. Noncanonical Streptococcus sanguinis ComCDE circuitry integrates environmental cues in transformation outcome decision. Cell Chem Biol 2024; 31:298-311.e6. [PMID: 37832551 PMCID: PMC10922391 DOI: 10.1016/j.chembiol.2023.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 07/25/2023] [Accepted: 09/18/2023] [Indexed: 10/15/2023]
Abstract
Natural competence is the principal driver of streptococcal evolution. While acquisition of new traits could facilitate rapid fitness improvement for bacteria, entry into the competent state is a highly orchestrated event, involving an interplay between various pathways. We present a new type of competence-predation coordination mechanism in Streptococcus sanguinis. Unlike other streptococci that mediate competence through the ComABCDE regulon, several key components are missing in the S. sanguinis ComCDE circuitry. We assembled two synthetic biology devices linking competence-stimulating peptide (CSP) cleavage and export with a quantifiable readout to unravel the unique features of the S. sanguinis circuitry. Our results revealed the ComC precursor cleavage pattern and the two host ABC transporters implicated in the export of the S. sanguinis CSP. Moreover, we discovered a ComCDE-dependent bacteriocin locus. Overall, this study presents a mechanism for commensal streptococci to maximize transformation outcome in a fluid environment through extensive circuitry rewiring.
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Affiliation(s)
- Mingzhe Guo
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia St, Reno, NV 89557, USA
| | - Clay P Renshaw
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia St, Reno, NV 89557, USA
| | - Ryan W Mull
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia St, Reno, NV 89557, USA
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia St, Reno, NV 89557, USA.
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Arbulu S, Kjos M. Revisiting the Multifaceted Roles of Bacteriocins : The Multifaceted Roles of Bacteriocins. MICROBIAL ECOLOGY 2024; 87:41. [PMID: 38351266 PMCID: PMC10864542 DOI: 10.1007/s00248-024-02357-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/01/2024] [Indexed: 02/16/2024]
Abstract
Bacteriocins are gene-encoded antimicrobial peptides produced by bacteria. These peptides are heterogeneous in terms of structure, antimicrobial activities, biosynthetic clusters, and regulatory mechanisms. Bacteriocins are widespread in nature and may contribute to microbial diversity due to their capacity to target specific bacteria. Primarily studied as food preservatives and therapeutic agents, their function in natural settings is however less known. This review emphasizes the ecological significance of bacteriocins as multifunctional peptides by exploring bacteriocin distribution, mobility, and their impact on bacterial population dynamics and biofilms.
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Affiliation(s)
- Sara Arbulu
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
| | - Morten Kjos
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
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Morales-Dorantes V, Domínguez-Pérez RA, Pérez-Serrano RM, Solís-Sainz JC, García-Solís P, Espinosa-Cristóbal LF, Cabeza-Cabrera CV, Ayala-Herrera JL. The Distribution of Eight Antimicrobial Resistance Genes in Streptococcus oralis, Streptococcus sanguinis, and Streptococcus gordonii Strains Isolated from Dental Plaque as Oral Commensals. Trop Med Infect Dis 2023; 8:499. [PMID: 37999618 PMCID: PMC10674312 DOI: 10.3390/tropicalmed8110499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 11/12/2023] [Accepted: 11/15/2023] [Indexed: 11/25/2023] Open
Abstract
It has been proposed that oral commensal bacteria are potential reservoirs of a wide variety of antimicrobial resistance genes (ARGs) and could be the source of pathogenic bacteria; however, there is scarce information regarding this. In this study, three common streptococci of the mitis group (S. oralis, S. sanguinis, and S. gordonii) isolated from dental plaque (DP) were screened to identify if they were frequent reservoirs of specific ARGs (blaTEM, cfxA, tetM, tetW, tetQ, ermA, ermB, and ermC). DP samples were collected from 80 adults; one part of the sample was cultured, and from the other part DNA was obtained for first screening of the three streptococci species and the ARGs of interest. Selected samples were plated and colonies were selected for molecular identification. Thirty identified species were screened for the presence of the ARGs. From those selected, all of the S. sanguinis and S. oralis carried at least three, while only 30% of S. gordonii strains carried three or more. The most prevalent were tetM in 73%, and blaTEM and tetW both in 66.6%. On the other hand, ermA and cfxA were not present. Oral streptococci from the mitis group could be considered frequent reservoirs of specifically tetM, blaTEM, and tetW. In contrast, these three species appear not to be reservoirs of ermA and cfxA.
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Affiliation(s)
- Verónica Morales-Dorantes
- Laboratory of Multidisciplinary Dentistry Research, Faculty of Medicine, Universidad Autónoma de Querétaro, Santiago de Querétaro 76176, Mexico
| | - Rubén Abraham Domínguez-Pérez
- Laboratory of Multidisciplinary Dentistry Research, Faculty of Medicine, Universidad Autónoma de Querétaro, Santiago de Querétaro 76176, Mexico
| | - Rosa Martha Pérez-Serrano
- Laboratorio de Genética y Biología Molecular, Faculty of Medicine, Universidad Autónoma de Querétaro, Santiago de Querétaro 76176, Mexico
| | - Juan Carlos Solís-Sainz
- Departamento de Investigación Biomédica, Faculty of Medicine, Universidad Autónoma de Querétaro, Santiago de Querétaro 76176, Mexico
| | - Pablo García-Solís
- Departamento de Investigación Biomédica, Faculty of Medicine, Universidad Autónoma de Querétaro, Santiago de Querétaro 76176, Mexico
| | - León Francisco Espinosa-Cristóbal
- Programa de Maestría en Ciencias Odontológicas, Departamento de Estomatología, Instituto de Ciencias Biomédicas, Universidad Autónoma de Ciudad Juárez, Ciudad Juárez 32310, Mexico
| | - Claudia Verónica Cabeza-Cabrera
- Clínica de la Licenciatura y Posgrados de Odontología, Faculty of Medicine, Universidad Autónoma de Querétaro, Santiago de Querétaro 76176, Mexico
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Herviou P, Balvay A, Bellet D, Bobet S, Maudet C, Staub J, Alric M, Leblond-Bourget N, Delorme C, Rabot S, Denis S, Payot S. Transfer of the Integrative and Conjugative Element ICE St3 of Streptococcus thermophilus in Physiological Conditions Mimicking the Human Digestive Ecosystem. Microbiol Spectr 2023; 11:e0466722. [PMID: 36995244 PMCID: PMC10269554 DOI: 10.1128/spectrum.04667-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 03/12/2023] [Indexed: 03/31/2023] Open
Abstract
Metagenome analyses of the human microbiome suggest that horizontal gene transfer (HGT) is frequent in these rich and complex microbial communities. However, so far, only a few HGT studies have been conducted in vivo. In this work, three different systems mimicking the physiological conditions encountered in the human digestive tract were tested, including (i) the TNO gastro-Intestinal tract Model 1 (TIM-1) system (for the upper part of the intestine), (ii) the ARtificial COLon (ARCOL) system (to mimic the colon), and (iii) a mouse model. To increase the likelihood of transfer by conjugation of the integrative and conjugative element studied in the artificial digestive systems, bacteria were entrapped in alginate, agar, and chitosan beads before being placed in the different gut compartments. The number of transconjugants detected decreased, while the complexity of the ecosystem increased (many clones in TIM-1 but only one clone in ARCOL). No clone was obtained in a natural digestive environment (germfree mouse model). In the human gut, the richness and diversity of the bacterial community would offer more opportunities for HGT events to occur. In addition, several factors (SOS-inducing agents, microbiota-derived factors) that potentially increase in vivo HGT efficiency were not tested here. Even if HGT events are rare, expansion of the transconjugant clones can happen if ecological success is fostered by selecting conditions or by events that destabilize the microbial community. IMPORTANCE The human gut microbiota plays a key role in maintaining normal host physiology and health, but its homeostasis is fragile. During their transit in the gastrointestinal tract, bacteria conveyed by food can exchange genes with resident bacteria. New traits acquired by HGT (e.g., new catabolic properties, bacteriocins, antibiotic resistance) can impact the gut microbial composition and metabolic potential. We showed here that TIM-1, a system mimicking the upper digestive tract, is a useful tool to evaluate HGT events in conditions closer to the physiological ones. Another important fact pointed out in this work is that Enterococcus faecalis is a good candidate for foreign gene acquisition. Due to its high ability to colonize the gut and acquire mobile genetic elements, this commensal bacterium could serve as an intermediate for HGT in the human gut.
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Affiliation(s)
- Pauline Herviou
- Université Clermont-Auvergne, INRAE, MEDIS, Clermont-Ferrand, France
| | - Aurélie Balvay
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Deborah Bellet
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Sophie Bobet
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Claire Maudet
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Johan Staub
- Université de Lorraine, INRAE, DynAMic, Nancy, France
| | - Monique Alric
- Université Clermont-Auvergne, INRAE, MEDIS, Clermont-Ferrand, France
| | | | - Christine Delorme
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Sylvie Rabot
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Sylvain Denis
- Université Clermont-Auvergne, INRAE, MEDIS, Clermont-Ferrand, France
| | - Sophie Payot
- Université de Lorraine, INRAE, DynAMic, Nancy, France
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Li L, Krieger M, Qin H, Zou Z, Kreth J, Merritt J. Adaptation of Prokaryotic Toxins for Negative Selection and Cloning-Independent Markerless Mutagenesis in Streptococcus Species. mSphere 2023:e0068222. [PMID: 37093065 DOI: 10.1128/msphere.00682-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023] Open
Abstract
The Streptococcus mutans genetic system offers a variety of strategies to rapidly engineer targeted chromosomal mutations. Previously, we reported the first S. mutans negative selection system that functions in a wild-type background. This system utilizes induced sensitivity to the toxic amino acid analog p-chlorophenylalanine (4-CP) as a negative selection mechanism and was developed for counterselection-based cloning-independent markerless mutagenesis (CIMM). While we have employed this system extensively for our ongoing genetic studies, we have encountered a couple limitations with the system, mainly its narrow host range and the requirement for selection on a toxic substrate. Here, we report the development of a new negative selection system that addresses both limitations, while still retaining the utility of the previous 4-CP-based markerless mutagenesis system. We placed a variety of toxin-encoding genes under the control of the xylose-inducible gene expression cassette (Xyl-S) and found the Fst-sm and ParE toxins to be suitable candidates for inducible negative selection. We combined the inducible toxins with an antibiotic resistance gene to create several different counterselection cassettes. The most broadly useful of these contained a wild-type fst-sm open reading frame transcriptionally fused to a point mutant form of the Xyl-S expression system, which we subsequently named IFDC4. IFDC4 was shown to exhibit exceptionally low background resistance, with 3- to 4-log reductions in cell number observed when plating on xylose-supplemented medium. IFDC4 also functioned similarly in multiple strains of S. mutans as well as with Streptococcus gordonii and Streptococcus sanguinis. We performed CIMM with IFDC4 and successfully engineered a variety of different types of markerless mutations in all three species. The counterselection strategy described here provides a template approach that should be adaptable for the creation of similar counterselection systems in many other bacteria. IMPORTANCE Multiple medically significant Streptococcus species, such as S. mutans, have highly sophisticated genetic systems available, largely as a consequence of their amenability to genetic manipulation via natural competence. Despite this, few options are available for the creation of markerless mutations in streptococci, especially within wild-type strains. Markerless mutagenesis is a critical tool for genetic studies, as it allows the user to explore many fundamental questions that are not easily addressable using marked mutagenesis. Here, we describe a new approach for streptococcal markerless mutagenesis that offers a variety of advantages over the current approach, which employs induced sensitivity to the toxic substrate 4-CP. The approach employed here should be readily adaptable for the creation of similar markerless mutagenesis systems in other organisms.
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Affiliation(s)
- Lena Li
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, Oregon, USA
| | - Madeline Krieger
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, Oregon, USA
| | - Hua Qin
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, Oregon, USA
| | - Zhengzhong Zou
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, Oregon, USA
| | - Jens Kreth
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, Oregon, USA
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon, USA
| | - Justin Merritt
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, Oregon, USA
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon, USA
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A Genome-Wide CRISPR Interference Screen Reveals an StkP-Mediated Connection between Cell Wall Integrity and Competence in Streptococcus salivarius. mSystems 2022; 7:e0073522. [PMID: 36342134 PMCID: PMC9765292 DOI: 10.1128/msystems.00735-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Competence is one of the most efficient bacterial evolutionary and adaptative strategies by synchronizing production of antibacterial compounds and integration of DNA released by dead cells. In most streptococci, this tactic is orchestrated by the ComRS system, a pheromone communication device providing a short time window of activation in which only part of the population is responsive. Understanding how this developmental process integrates multiple inputs to fine-tune the adequate response is a long-standing question. However, essential genes involved in the regulation of ComRS have been challenging to study. In this work, we built a conditional mutant library using CRISPR interference and performed three complementary screens to investigate competence genetic regulation in the human commensal Streptococcus salivarius. We show that initiation of competence increases upon cell wall impairment, suggesting a connection between cell envelope stress and competence activation. Notably, we report a key role for StkP, a serine-threonine kinase known to regulate cell wall homeostasis. We show that StkP controls competence by a mechanism that reacts to peptidoglycan fragments. Together, our data suggest a key cell wall sensing mechanism coupling competence to cell envelope integrity. IMPORTANCE Survival of human commensal streptococci in the digestive tract requires efficient strategies which must be tightly and collectively controlled for responding to competitive pressure and drastic environmental changes. In this context, the autocrine signaling system ComRS controlling competence for natural transformation and predation in salivarius streptococci could be seen as a multi-input device integrating a variety of environmental stimuli. In this work, we revealed novel positive and negative competence modulators by using a genome-wide CRISPR interference strategy. Notably, we highlighted an unexpected connection between bacterial envelope integrity and competence activation that involves several cell wall sensors. Together, these results showcase how commensal streptococci can fine-tune the pheromone-based competence system by responding to multiple inputs affecting their physiological status in order to calibrate an appropriate collective behavior.
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Uruén C, García C, Fraile L, Tommassen J, Arenas J. How Streptococcus suis escapes antibiotic treatments. Vet Res 2022; 53:91. [DOI: 10.1186/s13567-022-01111-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 09/13/2022] [Indexed: 11/13/2022] Open
Abstract
AbstractStreptococcus suis is a zoonotic agent that causes sepsis and meningitis in pigs and humans. S. suis infections are responsible for large economic losses in pig production. The lack of effective vaccines to prevent the disease has promoted the extensive use of antibiotics worldwide. This has been followed by the emergence of resistance against different classes of antibiotics. The rates of resistance to tetracyclines, lincosamides, and macrolides are extremely high, and resistance has spread worldwide. The genetic origin of S. suis resistance is multiple and includes the production of target-modifying and antibiotic-inactivating enzymes and mutations in antibiotic targets. S. suis genomes contain traits of horizontal gene transfer. Many mobile genetic elements carry a variety of genes that confer resistance to antibiotics as well as genes for autonomous DNA transfer and, thus, S. suis can rapidly acquire multiresistance. In addition, S. suis forms microcolonies on host tissues, which are associations of microorganisms that generate tolerance to antibiotics through a variety of mechanisms and favor the exchange of genetic material. Thus, alternatives to currently used antibiotics are highly demanded. A deep understanding of the mechanisms by which S. suis becomes resistant or tolerant to antibiotics may help to develop novel molecules or combinations of antimicrobials to fight these infections. Meanwhile, phage therapy and vaccination are promising alternative strategies, which could alleviate disease pressure and, thereby, antibiotic use.
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Wang S, Ma M, Liang Z, Zhu X, Yao H, Wang L, Wu Z. Pathogenic investigations of Streptococcus pasteurianus, an underreported zoonotic pathogen, isolated from a diseased piglet with meningitis. Transbound Emerg Dis 2022; 69:2609-2620. [PMID: 34871467 DOI: 10.1111/tbed.14413] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/28/2021] [Accepted: 11/28/2021] [Indexed: 01/14/2023]
Abstract
Streptococcus pasteurianus, an underreported opportunistic pathogen, is considered an increasingly recognized cause of meningitis and bacteremia in many animals and humans worldwide. However, except for some epidemiological studies, there is no report about the gene-deletion mutagenesis, virulence factors, reservoir niches or animal infection models for this pathogen. In this study, we first isolated an S. pasteurianus strain from a newly weaned piglet's brain with meningitis. The genomic sequence of this swine isolate WUSP067 shared high homology with that of two human strains. The comparative genome analysis showed that strain WUSP067 contained a fucose utilization cluster absent in human strains, and it shared 91% identity with that of an integrative and conjugative element (ICE) ICEssuZJ20091101-2 from Streptococcus suis, another important swine bacterial pathogen. Strain WUSP067 was resistant to erythromycin, tulathromycin, lincomycin, clindamycin, doxycycline and gentamycin, and ICEs are vehicles for harbouring antimicrobial resistance genes. The infection model was established using the 3-week-old newly weaned ICR mice. The 50% lethal dose value of strain WUSP067 was 4.0 × 107 colony-forming units per mouse. The infected mice showed severe signs of meningitis and pathological changes in brains. Furthermore, the capsule-deficient mutant was generated using natural transformation, and we showed that capsule was an essential virulence factor for S. pasteurianus. In addition, we found that tonsils and hilar lymph nodes of healthy pigs may be reservoir niches for this bacterium. Thus, our study provided valuable information about the pathogenetic characteristics and antimicrobial resistance of S. pasteurianus and paved the way for studying its pathogenesis.
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Affiliation(s)
- Shuoyue Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Miaohang Ma
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Zijing Liang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Xinchi Zhu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Huochun Yao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Liping Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Zongfu Wu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
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12
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Brennan AA, Mehrani M, Tal-Gan Y. Modulating streptococcal phenotypes using signal peptide analogues. Open Biol 2022; 12:220143. [PMID: 35920042 PMCID: PMC9346555 DOI: 10.1098/rsob.220143] [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] [Indexed: 12/13/2022] Open
Abstract
Understanding bacterial communication mechanisms is imperative to improve our current understanding of bacterial infectivity and find alternatives to current modes of antibacterial therapeutics. Both Gram-positive and Gram-negative bacteria use quorum sensing (QS) to regulate group behaviours and associated phenotypes in a cell-density-dependent manner. Group behaviours, phenotypic expression and resultant infection and disease can largely be attributed to efficient bacterial communication. Of particular interest are the communication mechanisms of Gram-positive bacteria known as streptococci. This group has demonstrated marked resistance to traditional antibiotic treatment, resulting in increased morbidity and mortality of infected hosts and an ever-increasing burden on the healthcare system. Modulating circuits and mechanisms involved in streptococcal communication has proven to be a promising anti-virulence therapeutic approach that allows managing bacterial phenotypic response but does not affect bacterial viability. Targeting the chemical signals bacteria use for communication is a promising starting point, as manipulation of these signals can dramatically affect resultant bacterial phenotypes, minimizing associated morbidity and mortality. This review will focus on the use of modified peptide signals in modulating the development of proliferative phenotypes in different streptococcal species, specifically regarding how such modification can attenuate bacterial infectivity and aid in developing future alternative therapeutic agents.
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Affiliation(s)
- Alec A Brennan
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557, USA
| | - Mona Mehrani
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557, USA
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557, USA
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13
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Tang X, Yang Z, Dai K, Liu G, Chang YF, Tang X, Wang K, Zhang Y, Hu B, Cao S, Huang X, Yan Q, Wu R, Zhao Q, Du S, Lang Y, Han X, Huang Y, Wen X, Wen Y. The molecular diversity of transcriptional factor TfoX is a determinant in natural transformation in Glaesserella parasuis. Front Microbiol 2022; 13:948633. [PMID: 35966685 PMCID: PMC9372613 DOI: 10.3389/fmicb.2022.948633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 07/12/2022] [Indexed: 11/13/2022] Open
Abstract
Natural transformation is a mechanism by which a particular bacterial species takes up foreign DNA and integrates it into its genome. The swine pathogen Glaesserella parasuis (G. parasuis) is a naturally transformable bacterium. The regulation of competence, however, is not fully understood. In this study, the natural transformability of 99 strains was investigated. Only 44% of the strains were transformable under laboratory conditions. Through a high-resolution melting curve and phylogenetic analysis, we found that genetic differences in the core regulator of natural transformation, the tfoX gene, leads to two distinct natural transformation phenotypes. In the absence of the tfoX gene, the highly transformable strain SC1401 lost its natural transformability. In addition, when the SC1401 tfoX gene was replaced by the tfoX of SH0165, which has no natural transformability, competence was also lost. These results suggest that TfoX is a core regulator of natural transformation in G. parasuis, and that differences in tfoX can be used as a molecular indicator of natural transformability. Transcriptomic and proteomic analyses of the SC1401 wildtype strain, and a tfoX gene deletion strain showed that differential gene expression and protein synthesis is mainly centered on pathways related to glucose metabolism. The results suggest that tfoX may mediate natural transformation by regulating the metabolism of carbon sources. Our study provides evidence that tfoX plays an important role in the natural transformation of G. parasuis.
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Affiliation(s)
- Xiaoyu Tang
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Zhen Yang
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Ke Dai
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Geyan Liu
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yung-Fu Chang
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Xinwei Tang
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Kang Wang
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yiwen Zhang
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Bangdi Hu
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Sanjie Cao
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xiaobo Huang
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Qigui Yan
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Rui Wu
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Qin Zhao
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Senyan Du
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yifei Lang
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xinfeng Han
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yong Huang
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xintian Wen
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yiping Wen
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
- *Correspondence: Yiping Wen,
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14
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Pandey SD, Biswas I. Clp ATPases differentially affect natural competence development in Streptococcus mutans. Microbiologyopen 2022; 11:e1288. [PMID: 35765180 PMCID: PMC9108599 DOI: 10.1002/mbo3.1288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 04/27/2022] [Indexed: 11/25/2022] Open
Abstract
In naturally competent bacteria, DNA transformation through horizontal gene transfer is an evolutionary mechanism to receive extracellular DNA. Bacteria need to maintain a state of competence to accept foreign DNA, and this is an energy-driven phenomenon that is tightly controlled. In Streptococcus, competence development is a complex process that is not fully understood. In this study, we used Streptococcus mutans, an oral bacterium, to determine how cell density affects competence development. We found that in S. mutans the transformation efficiency is maximum when the transforming DNA was added at low cell density and incubated for 2.5 h before selecting for transformants. We also found that S. mutans cells remain competent until the mid-logarithmic phase, after which the competence decreases drastically. Surprisingly, we observed that individual components of Clp proteolytic complexes differentially regulate competence. If the transformation is carried out at the early growth phase, both ClpP protease and ClpX ATPase are needed for competence. In contrast, we found that both ClpC and ClpE negatively affect competence. We also found that if the transformation is carried out at the mid-logarithmic growth phase ClpX is still required for competence, but ClpP negatively affects competence. While the exact reason for this differential effect of ClpP and ClpX on transformation is currently unknown, we found that both ClpC and ClpE have a negative effect on transformation, which was not reported before.
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Affiliation(s)
- Satya D. Pandey
- Department of MicrobiologyUniversity of Kansas Medical CenterKansas CityKansasUSA
| | - Indranil Biswas
- Department of MicrobiologyUniversity of Kansas Medical CenterKansas CityKansasUSA
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15
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O'Connell LM, Kelleher P, van Rijswijck IMH, de Waal P, van Peij NNME, Mahony J, van Sinderen D. Natural Transformation in Gram-Positive Bacteria and Its Biotechnological Relevance to Lactic Acid Bacteria. Annu Rev Food Sci Technol 2022; 13:409-431. [PMID: 35333592 DOI: 10.1146/annurev-food-052720-011445] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Competence refers to the specialized physiological state in which bacteria undergo transformation through the internalization of exogenous DNA in a controlled and genetically encoded process that leads to genotypic and, in many cases, phenotypic changes. Natural transformation was first described in Streptococcus pneumoniae and has since been demonstrated in numerous species, including Bacillus subtilis and Neisseria gonorrhoeae. Homologs of the genes encoding the DNA uptake machinery for natural transformation have been reported to be present in several lactic acid bacteria, including Lactobacillus spp., Streptococcus thermophilus, and Lactococcus spp. In this review, we collate current knowledge of the phenomenon of natural transformation in Gram-positive bacteria. Furthermore, we describe the mechanism of competence development and its regulation in model bacterial species. We highlight the importance and opportunities for the application of these findings in the context of bacterial starter cultures associated with food fermentations as well as current limitations in this area of research.
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Affiliation(s)
- Laura M O'Connell
- APC Microbiome Ireland and School of Microbiology, University College Cork, Cork, Ireland;
| | - Philip Kelleher
- APC Microbiome Ireland and School of Microbiology, University College Cork, Cork, Ireland;
| | | | - Paul de Waal
- DSM Biotechnology Center, Delft, The Netherlands
| | | | - Jennifer Mahony
- APC Microbiome Ireland and School of Microbiology, University College Cork, Cork, Ireland;
| | - Douwe van Sinderen
- APC Microbiome Ireland and School of Microbiology, University College Cork, Cork, Ireland;
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16
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The CovRS Environmental Sensor Directly Controls the ComRS Signaling System To Orchestrate Competence Bimodality in Salivarius Streptococci. mBio 2022; 13:e0312521. [PMID: 35089064 PMCID: PMC8725580 DOI: 10.1128/mbio.03125-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In bacteria, phenotypic heterogeneity in an isogenic population compensates for the lack of genetic diversity and allows concomitant multiple survival strategies when choosing only one is too risky. This powerful tactic is exploited for competence development in streptococci where only a subset of the community triggers the pheromone signaling system ComR-ComS, resulting in a bimodal activation. However, the regulatory cascade and the underlying mechanisms of this puzzling behavior remained partially understood. Here, we show that CovRS, a well-described virulence regulatory system in pathogenic streptococci, directly controls the ComRS system to generate bimodality in the gut commensal Streptococcus salivarius and the closely related species Streptococcus thermophilus. Using single-cell analysis of fluorescent reporter strains together with regulatory mutants, we revealed that the intracellular concentration of ComR determines the proportion of competent cells in the population. We also showed that this bimodal activation requires a functional positive-feedback loop acting on ComS production, as well as its exportation and reinternalization via dedicated permeases. As the intracellular ComR concentration is critical in this process, we hypothesized that an environmental sensor could control its abundance. We systematically inactivated all two-component systems and identified CovRS as a direct repression system of comR expression. Notably, we showed that the system transduces its negative regulation through CovR binding to multiple sites in the comR promoter region. Since CovRS integrates environmental stimuli, we suggest that it is the missing piece of the puzzle that connects environmental conditions to (bimodal) competence activation in salivarius streptococci. IMPORTANCE Combining production of antibacterial compounds and uptake of DNA material released by dead cells, competence is one of the most efficient survival strategies in streptococci. Yet, this powerful tactic is energy consuming and reprograms the metabolism to such an extent that cell proliferation is transiently impaired. To circumvent this drawback, competence activation is restricted to a subpopulation, a process known as bimodality. In this work, we explored this phenomenon in salivarius streptococci and elucidated the molecular mechanisms governing cell fate. We also show that an environmental sensor controlling virulence in pathogenic streptococci is diverted to control competence in commensal streptococci. Together, those results showcase how bacteria can sense and transmit external stimuli to complex communication devices for fine-tuning collective behaviors.
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17
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Di Giacomo S, Toussaint F, Ledesma-García L, Knoops A, Vande Capelle F, Fremaux C, Horvath P, Ladrière JM, Ait-Abderrahim H, Hols P, Mignolet J. OUP accepted manuscript. FEMS Microbiol Rev 2022; 46:6543703. [PMID: 35254446 PMCID: PMC9300618 DOI: 10.1093/femsre/fuac014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/14/2022] [Accepted: 03/01/2022] [Indexed: 11/14/2022] Open
Abstract
Nowadays, the growing human population exacerbates the need for sustainable resources. Inspiration and achievements in nutrient production or human/animal health might emanate from microorganisms and their adaptive strategies. Here, we exemplify the benefits of lactic acid bacteria (LAB) for numerous biotechnological applications and showcase their natural transformability as a fast and robust method to hereditarily influence their phenotype/traits in fundamental and applied research contexts. We described the biogenesis of the transformation machinery and we analyzed the genome of hundreds of LAB strains exploitable for human needs to predict their transformation capabilities. Finally, we provide a stepwise rational path to stimulate and optimize natural transformation with standard and synthetic biology techniques. A comprehensive understanding of the molecular mechanisms driving natural transformation will facilitate and accelerate the improvement of bacteria with properties that serve broad societal interests.
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Affiliation(s)
- Stefano Di Giacomo
- Biochemistry and Genetics of Microorganisms (BGM), Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud 4-5, (box L7.07.06), B-1348 Louvain-la-Neuve, Belgium
| | - Frédéric Toussaint
- Biochemistry and Genetics of Microorganisms (BGM), Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud 4-5, (box L7.07.06), B-1348 Louvain-la-Neuve, Belgium
| | - Laura Ledesma-García
- Biochemistry and Genetics of Microorganisms (BGM), Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud 4-5, (box L7.07.06), B-1348 Louvain-la-Neuve, Belgium
| | - Adrien Knoops
- Biochemistry and Genetics of Microorganisms (BGM), Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud 4-5, (box L7.07.06), B-1348 Louvain-la-Neuve, Belgium
| | - Florence Vande Capelle
- Biochemistry and Genetics of Microorganisms (BGM), Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud 4-5, (box L7.07.06), B-1348 Louvain-la-Neuve, Belgium
| | - Christophe Fremaux
- Health and Biosciences, IFF Danisco France SAS, CS 10010, F-86220 Dangé-Saint-Romain, France
| | - Philippe Horvath
- Health and Biosciences, IFF Danisco France SAS, CS 10010, F-86220 Dangé-Saint-Romain, France
| | - Jean-Marc Ladrière
- Health and Biosciences, IFF Danisco France SAS, CS 10010, F-86220 Dangé-Saint-Romain, France
| | | | - Pascal Hols
- Corresponding author: Biochemistry and Genetics of Microorganisms, Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud 4-5 (box L7.07.06), B-1348 Louvain-La-Neuve, Belgium. Tel: +3210478896; Fax: +3210472825; E-mail:
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18
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Rebuffat S. Ribosomally synthesized peptides, foreground players in microbial interactions: recent developments and unanswered questions. Nat Prod Rep 2021; 39:273-310. [PMID: 34755755 DOI: 10.1039/d1np00052g] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
It is currently well established that multicellular organisms live in tight association with complex communities of microorganisms including a large number of bacteria. These are immersed in complex interaction networks reflecting the relationships established between them and with host organisms; yet, little is known about the molecules and mechanisms involved in these mutual interactions. Ribosomally synthesized peptides, among which bacterial antimicrobial peptides called bacteriocins and microcins have been identified as contributing to host-microbe interplays, are either unmodified or post-translationally modified peptides. This review will unveil current knowledge on these ribosomal peptide-based natural products, their interplay with the host immune system, and their roles in microbial interactions and symbioses. It will include their major structural characteristics and post-translational modifications, the main rules of their maturation pathways, and the principal ecological functions they ensure (communication, signalization, competition), especially in symbiosis, taking select examples in various organisms. Finally, we address unanswered questions and provide a framework for deciphering big issues inspiring future directions in the field.
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Affiliation(s)
- Sylvie Rebuffat
- Laboratory Molecules of Communication and Adaptation of Microorganisms (MCAM, UMR 7245 CNRS-MNHN), National Museum of Natural History (MNHN), National Centre of Scientific Research (CNRS), CP 54, 57 rue Cuvier 75005, Paris, France.
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19
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Coevolution of the bacterial pheromone ComS and sensor ComR fine-tunes natural transformation in streptococci. J Biol Chem 2021; 297:101346. [PMID: 34715127 PMCID: PMC8605241 DOI: 10.1016/j.jbc.2021.101346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 10/17/2021] [Accepted: 10/18/2021] [Indexed: 11/22/2022] Open
Abstract
Competence for natural transformation extensively contributes to genome evolution and the rapid adaptability of bacteria dwelling in challenging environments. In most streptococci, this process is tightly controlled by the ComRS signaling system, which is activated through the direct interaction between the (R)RNPP-type ComR sensor and XIP pheromone (mature ComS). The overall mechanism of activation and the basis of pheromone selectivity have been previously reported in Gram-positive salivarius streptococci; however, detailed 3D-remodeling of ComR leading up to its activation remains only partially understood. Here, we identified using a semirational mutagenesis approach two residues in the pheromone XIP that bolster ComR sensor activation by interacting with two aromatic residues of its XIP-binding pocket. Random and targeted mutagenesis of ComR revealed that the interplay between these four residues remodels a network of aromatic–aromatic interactions involved in relaxing the sequestration of the DNA-binding domain. Based on these data, we propose a comprehensive model for ComR activation based on two major conformational changes of the XIP-binding domain. Notably, the stimulation of this newly identified trigger point by a single XIP substitution resulted in higher competence and enhanced transformability, suggesting that pheromone-sensor coevolution counter-selects for hyperactive systems in order to maintain a trade-off between competence and bacterial fitness. Overall, this study sheds new light on the ComRS activation mechanism and how it could be exploited for biotechnological and biomedical purposes.
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20
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The transcription regulator BrsR serves as a network hub of natural competence protein-protein interactions in Streptococcus mutans. Proc Natl Acad Sci U S A 2021; 118:2106048118. [PMID: 34544866 DOI: 10.1073/pnas.2106048118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2021] [Indexed: 11/18/2022] Open
Abstract
Genome evolution is an essential and stringently regulated aspect of biological fitness. For bacteria, natural competence is one of the principal mechanisms of genome evolution and is frequently subject to multiple layers of regulation derived from a plethora of environmental and physiological stimuli. Here, we present a regulatory mechanism that illustrates how such disparate stimuli can be integrated into the Streptococcus mutans natural competence phenotype. S. mutans possesses an intriguing, but poorly understood ability to coordinately control its independently regulated natural competence and bacteriocin genetic pathways as a means to acquire DNA released from closely related, bacteriocin-susceptible streptococci. Our results reveal how the bacteriocin-specific transcription activator BrsR directly mediates this coordination by serving as an anti-adaptor protein responsible for antagonizing the proteolysis of the inherently unstable, natural competence-specific alternative sigma factor ComX. This BrsR ability functions entirely independent of its transcription regulator function and directly modulates the timing and severity of the natural competence phenotype. Additionally, many of the DNA uptake proteins produced by the competence system were surprisingly found to possess adaptor abilities, which are employed to terminate the BrsR regulatory circuit via negative feedback. BrsR-competence protein heteromeric complexes directly inhibit nascent brsR transcription as well as stimulate the Clp-dependent proteolysis of extant BrsR proteins. This study illustrates how critical genetic regulatory abilities can evolve in a potentially limitless variety of proteins without disrupting their conserved ancestral functions. These unrecognized regulatory abilities are likely fundamental for transducing information through complex genetic networks.
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21
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Rutbeek NR, Rezasoltani H, Patel TR, Khajehpour M, Prehna G. Molecular mechanism of quorum sensing inhibition in Streptococcus by the phage protein paratox. J Biol Chem 2021; 297:100992. [PMID: 34298018 PMCID: PMC8383118 DOI: 10.1016/j.jbc.2021.100992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/15/2021] [Accepted: 07/19/2021] [Indexed: 11/25/2022] Open
Abstract
Streptococcus pyogenes, or Group A Streptococcus, is a Gram-positive bacterium that can be both a human commensal and a pathogen. Central to this dichotomy are temperate bacteriophages that incorporate into the bacterial genome as prophages. These genetic elements encode both the phage proteins and the toxins harmful to the human host. One such conserved phage protein, paratox (Prx), is always found encoded adjacent to the toxin genes, and this linkage is preserved during all stages of the phage life cycle. Within S. pyogenes, Prx functions to inhibit the quorum-sensing receptor-signal pair ComRS, the master regulator of natural competence, or the ability to uptake endogenous DNA. However, the mechanism by which Prx directly binds and inhibits the receptor ComR is unknown. To understand how Prx inhibits ComR at the molecular level, we pursued an X-ray crystal structure of Prx bound to ComR. The structural data supported by solution X-ray scattering data demonstrate that Prx induces a conformational change in ComR to directly access its DNA-binding domain. Furthermore, electromobility shift assays and competition binding assays reveal that Prx effectively uncouples the interdomain conformational change required for activation of ComR via the signaling molecule XIP. Although to our knowledge the molecular mechanism of quorum-sensing inhibition by Prx is unique, it is analogous to the mechanism employed by the phage protein Aqs1 in Pseudomonas aeruginosa. Together, this demonstrates an example of convergent evolution between Gram-positive and Gram-negative phages to inhibit quorum-sensing and highlights the versatility of small phage proteins.
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Affiliation(s)
- Nicole R Rutbeek
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Hanieh Rezasoltani
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Trushar R Patel
- Department of Chemistry and Biochemistry, University of Lethbridge, Alberta, Canada
| | - Mazdak Khajehpour
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Gerd Prehna
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada.
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22
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Dechêne-Tempier M, Marois-Créhan C, Libante V, Jouy E, Leblond-Bourget N, Payot S. Update on the Mechanisms of Antibiotic Resistance and the Mobile Resistome in the Emerging Zoonotic Pathogen Streptococcus suis. Microorganisms 2021; 9:microorganisms9081765. [PMID: 34442843 PMCID: PMC8401462 DOI: 10.3390/microorganisms9081765] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 11/30/2022] Open
Abstract
Streptococcus suis is a zoonotic pathogen causing important economic losses in swine production. The most commonly used antibiotics in swine industry are tetracyclines, beta-lactams, and macrolides. Resistance to these antibiotics has already been observed worldwide (reaching high rates for macrolides and tetracyclines) as well as resistance to aminoglycosides, fluoroquinolones, amphenicols, and glycopeptides. Most of the resistance mechanisms are encoded by antibiotic resistance genes, and a large part are carried by mobile genetic elements (MGEs) that can be transferred through horizontal gene transfer. This review provides an update of the resistance genes, their combination in multidrug isolates, and their localization on MGEs in S. suis. It also includes an overview of the contribution of biofilm to antimicrobial resistance in this bacterial species. The identification of resistance genes and study of their localization in S. suis as well as the environmental factors that can modulate their dissemination appear essential in order to decipher the role of this bacterium as a reservoir of antibiotic genes for other species.
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Affiliation(s)
- Manon Dechêne-Tempier
- Anses Laboratoire de Ploufragan-Plouzané-Niort, Unité Mycoplasmologie, Bactériologie et Antibiorésistance, F-22440 Ploufragan, France; (M.D.-T.); (C.M.-C.); (E.J.)
- Université de Lorraine, INRAE, DynAMic, F-54000 Nancy, France; (V.L.); (N.L.-B.)
| | - Corinne Marois-Créhan
- Anses Laboratoire de Ploufragan-Plouzané-Niort, Unité Mycoplasmologie, Bactériologie et Antibiorésistance, F-22440 Ploufragan, France; (M.D.-T.); (C.M.-C.); (E.J.)
| | - Virginie Libante
- Université de Lorraine, INRAE, DynAMic, F-54000 Nancy, France; (V.L.); (N.L.-B.)
| | - Eric Jouy
- Anses Laboratoire de Ploufragan-Plouzané-Niort, Unité Mycoplasmologie, Bactériologie et Antibiorésistance, F-22440 Ploufragan, France; (M.D.-T.); (C.M.-C.); (E.J.)
| | | | - Sophie Payot
- Université de Lorraine, INRAE, DynAMic, F-54000 Nancy, France; (V.L.); (N.L.-B.)
- Correspondence:
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23
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Yuan L, Wu H, Wang B, Jia C, Liang D, Caiyin QGL, Qiao J. ComX improves acid tolerance by regulating the expression of late competence proteins in Lactococcus lactis F44. J Dairy Sci 2021; 104:9556-9569. [PMID: 34147226 DOI: 10.3168/jds.2021-20184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 05/07/2021] [Indexed: 12/22/2022]
Abstract
ComX can improve bacterial competence by modulating global gene expression. Although competence induction may also be a protective mechanism under stress, this has not been investigated in detail. Here, we demonstrated that ComX improved the acid tolerance and nisin yield of Lactococcus lactis, which is an important gram-positive bacterium increasingly used in modern biotechnological applications. We found that overexpression of comX could improve the survival rate up to 36.5% at pH 4.0, compared with only 5.4% and 1.1% with the wild-type and comX knockout strains, respectively. Moreover, quantitative real-time PCR results indicated that comX overexpression stimulated the expression of late competence genes synergistically with exposure to acid stress. Finally, electrophoretic mobility shift assay demonstrated the binding of purified ComX to the cin-box in the promoters of these genes. Taken together, our results reveal a regulation mechanism by which ComX and acid stress can synergistically modulate the expression of late competence genes to enhance cells' acid tolerance and nisin yield.
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Affiliation(s)
- Lin Yuan
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China; Department of Bioengineering, School of Food Science and Bioengineering, Tianjin Agricultural University, Tianjin 300072, P. R. China; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, P. R. China
| | - Hao Wu
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, P. R. China; Zhejiang Shaoxing Research Institute of Tianjin University, Shaoxing 312300, P. R. China
| | - Binbin Wang
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, P. R. China; School of Life Science, Shanxi Normal University, Linfen 41000, P. R. China
| | - Cuili Jia
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Dongmei Liang
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China; Zhejiang Shaoxing Research Institute of Tianjin University, Shaoxing 312300, P. R. China
| | - Qing-Ge-Le Caiyin
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Jianjun Qiao
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, P. R. China; Zhejiang Shaoxing Research Institute of Tianjin University, Shaoxing 312300, P. R. China.
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Li JW, Wyllie RM, Jensen PA. A Novel Competence Pathway in the Oral Pathogen Streptococcus sobrinus. J Dent Res 2021; 100:542-548. [PMID: 33876976 DOI: 10.1177/0022034520979150] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Streptococcus sobrinus is an etiologic cause of dental caries (tooth decay) in humans. Our knowledge of S. sobrinus is scant despite the organism's important role in oral health. It is widely believed that S. sobrinus lacks the natural competence pathways that are used by other streptococci to regulate growth, virulence, and quorum sensing. The lack of natural competence has also prevented genetic manipulation of S. sobrinus, limiting our knowledge of its pathogenicity. We discovered that most strains of S. sobrinus contain a new class of the ComRS competence system. Although S. sobrinus is typically placed among the mutans group streptococci, the S. sobrinus ComRS system is most similar to the competence pathways in the salivarius group. Unlike all other ComRS systems, the S. sobrinus pathway contains 2 copies of the transcriptional regulator ComR and has a peptide pheromone (XIP) that lacks any aromatic amino acids. Synthetic XIP enables transformation of S. sobrinus with plasmid or linear DNA, and we leverage this newfound genetic tractability to confirm that only 1 of the ComR homologs is required for induced competence while the other appears to suppress competence. Exogenous XIP increases the expression of bacteriocin gene clusters and produces an antimicrobial response that inhibits growth of S. mutans. We also identified 2 strains of S. sobrinus that appear to be "cheaters" by either not responding to or not producing XIP. We show how a recombination event in the nonresponsive strain could restore function of the ComRS pathway but delete the gene encoding XIP. Thus, the S. sobrinus ComRS pathway provides new tools for studying this pathogen and offers a lens into the evolution of ecological cheaters.
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Affiliation(s)
- J W Li
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - R M Wyllie
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - P A Jensen
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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25
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Ferrando ML, Gussak A, Mentink S, Gutierrez MF, van Baarlen P, Wells JM. Active Human and Porcine Serum Induce Competence for Genetic Transformation in the Emerging Zoonotic Pathogen Streptococcus suis. Pathogens 2021; 10:pathogens10020156. [PMID: 33546136 PMCID: PMC7913127 DOI: 10.3390/pathogens10020156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 11/16/2022] Open
Abstract
The acquisition of novel genetic traits through natural competence is a strategy used by bacteria in microbe-rich environments where microbial competition, antibiotics, and host immune defenses threaten their survival. Here, we show that virulent strains of Streptococcus suis, an important zoonotic agent and porcine pathogen, become competent for genetic transformation with plasmid or linear DNA when cultured in active porcine and human serum. Competence was not induced in active fetal bovine serum, which contains less complement factors and immunoglobulins than adult serum and was strongly reduced in heat-treated or low-molecular weight fractions of active porcine serum. Late competence genes, encoding the uptake machinery for environmental DNA, were upregulated in the active serum. Competence development was independent of the early competence regulatory switch involving XIP and ComR, as well as sigma factor ComX, suggesting the presence of an alternative stress-induced pathway for regulation of the late competence genes required for DNA uptake.
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26
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Kaspar JR, Lee K, Richard B, Walker AR, Burne RA. Direct interactions with commensal streptococci modify intercellular communication behaviors of Streptococcus mutans. THE ISME JOURNAL 2021; 15:473-488. [PMID: 32999420 PMCID: PMC8027600 DOI: 10.1038/s41396-020-00789-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 09/10/2020] [Accepted: 09/18/2020] [Indexed: 02/07/2023]
Abstract
The formation of dental caries is a complex process that ultimately leads to damage of the tooth enamel from acids produced by microbes in attached biofilms. The bacterial interactions occurring within these biofilms between cariogenic bacteria, such as the mutans streptococci, and health-associated commensal streptococci, are thought to be critical determinants of health and disease. To better understand these interactions, a Streptococcus mutans reporter strain that actively monitors cell-cell communication via peptide signaling was cocultured with different commensal streptococci. Signaling by S. mutans, normally highly active in monoculture, was completely inhibited by several species of commensals, but only when the bacteria were in direct contact with S. mutans. We identified a novel gene expression pattern that occurred in S. mutans when cultured directly with these commensals. Finally, mutant derivatives of commensals lacking previously shown antagonistic gene products displayed wild-type levels of signal inhibition in cocultures. Collectively, these results reveal a novel pathway(s) in multiple health-associated commensal streptococci that blocks peptide signaling and induces a common contact-dependent pattern of differential gene expression in S. mutans. Understanding the molecular basis for this inhibition will assist in the rational design of new risk assessments, diagnostics, and treatments for the most pervasive oral infectious diseases.
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Affiliation(s)
- Justin R Kaspar
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA.
- Division of Biosciences, College of Dentistry, Ohio State University, Columbus, OH, USA.
| | - Kyulim Lee
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Brook Richard
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Alejandro R Walker
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Robert A Burne
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
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27
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Ishkov IP, Kaspar JR, Hagen SJ. Spatial Correlations and Distribution of Competence Gene Expression in Biofilms of Streptococcus mutans. Front Microbiol 2021; 11:627992. [PMID: 33510740 PMCID: PMC7835332 DOI: 10.3389/fmicb.2020.627992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/17/2020] [Indexed: 11/13/2022] Open
Abstract
Streptococcus mutans is an important pathogen in the human oral biofilm. It expresses virulent behaviors that are linked to its genetic competence regulon, which is controlled by comX. Expression of comX is modulated by two diffusible signaling peptides, denoted CSP and XIP, and by other environmental cues such as pH and oxidative stress. The sensitivity of S. mutans competence to environmental inputs that may vary on microscopic length scales raises the question of whether the biofilm environment creates microniches where competence and related phenotypes are concentrated, leading to spatial clustering of S. mutans virulence behaviors. We have used two-photon microscopy to characterize the spatial distribution of comX expression among individual S. mutans cells in biofilms. By analyzing correlations in comX activity, we test for spatial clustering that may suggest localized competence microenvironments. Our data indicate that both competence-signaling peptides diffuse efficiently through the biofilm. XIP elicits a population-wide response. CSP triggers a Poisson-like, spatially random comX response from a subpopulation of cells that is homogeneously dispersed. Our data indicate that competence microenvironments if they exist are small enough that the phenotypes of individual cells are not clustered or correlated to any greater extent than occurs in planktonic cultures.
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Affiliation(s)
- Ivan P Ishkov
- Department of Physics, University of Florida, Gainesville, FL, United States
| | - Justin R Kaspar
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, United States
| | - Stephen J Hagen
- Department of Physics, University of Florida, Gainesville, FL, United States
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28
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Alves-Barroco C, Paquete-Ferreira J, Santos-Silva T, Fernandes AR. Singularities of Pyogenic Streptococcal Biofilms - From Formation to Health Implication. Front Microbiol 2021; 11:584947. [PMID: 33424785 PMCID: PMC7785724 DOI: 10.3389/fmicb.2020.584947] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 11/20/2020] [Indexed: 01/09/2023] Open
Abstract
Biofilms are generally defined as communities of cells involved in a self-produced extracellular matrix adhered to a surface. In biofilms, the bacteria are less sensitive to host defense mechanisms and antimicrobial agents, due to multiple strategies, that involve modulation of gene expression, controlled metabolic rate, intercellular communication, composition, and 3D architecture of the extracellular matrix. These factors play a key role in streptococci pathogenesis, contributing to therapy failure and promoting persistent infections. The species of the pyogenic group together with Streptococcus pneumoniae are the major pathogens belonging the genus Streptococcus, and its biofilm growth has been investigated, but insights in the genetic origin of biofilm formation are limited. This review summarizes pyogenic streptococci biofilms with details on constitution, formation, and virulence factors associated with formation.
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Affiliation(s)
- Cinthia Alves-Barroco
- UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, Caparica, Portugal
| | - João Paquete-Ferreira
- UCIBIO, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, Caparica, Portugal
| | - Teresa Santos-Silva
- UCIBIO, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, Caparica, Portugal
| | - Alexandra R Fernandes
- UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, Caparica, Portugal
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29
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García-Curiel L, Del Rocío López-Cuellar M, Rodríguez-Hernández AI, Chavarría-Hernández N. Toward understanding the signals of bacteriocin production by Streptococcus spp. and their importance in current applications. World J Microbiol Biotechnol 2021; 37:15. [PMID: 33394178 DOI: 10.1007/s11274-020-02973-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 12/01/2020] [Indexed: 12/25/2022]
Abstract
Microorganisms have developed quorum sensing (QS) systems to detect small signaling molecules that help to control access to additional nutrients and space in highly competitive polymicrobial niches. Many bacterial processes are QS-regulated; two examples are the highly related traits of the natural genetic competence state and the production of antimicrobial peptides such as bacteriocins. The Streptococcus genus is widely studied for its competence and for its ability to produce bacteriocins, as these antimicrobial peptides have significant potential in the treatment of infections caused by multiple-resistant pathogens, a severe public health issue. The transduction of a two-component system controls competence in streptococci: (1) ComD/E, which controls the competence in the Mitis and Anginosus groups, and (2) ComR/S, which performs the same function in the Bovis, Mutans, Salivarius, and Pyogenic groups. The cell-to-cell communication required for bacteriocin production in the Streptococcus groups is controlled mainly by a paralog of the ComD/E system. The relationships between pheromone signals and induction pathways are related to the bacteriocin production systems. In this review, we discuss the recent advances in the understanding of signaling and the induction of bacteriocin biosynthesis by QS regulation in streptococci. This information could aid in the design of better methods for the development and production of these antimicrobial peptides. It could also contribute to the analysis and emerging applications of bacteriocins in terms of their safety, quality, and human health benefits.
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Affiliation(s)
- Laura García-Curiel
- Cuerpo Académico de Biotecnología Agroalimentaria, Instituto de Ciencias Agropecuarias-Universidad Autónoma del Estado de Hidalgo, Tulancingo de Bravo, México
| | - Ma Del Rocío López-Cuellar
- Cuerpo Académico de Biotecnología Agroalimentaria, Instituto de Ciencias Agropecuarias-Universidad Autónoma del Estado de Hidalgo, Tulancingo de Bravo, México.
| | - Adriana Inés Rodríguez-Hernández
- Cuerpo Académico de Biotecnología Agroalimentaria, Instituto de Ciencias Agropecuarias-Universidad Autónoma del Estado de Hidalgo, Tulancingo de Bravo, México
| | - Norberto Chavarría-Hernández
- Cuerpo Académico de Biotecnología Agroalimentaria, Instituto de Ciencias Agropecuarias-Universidad Autónoma del Estado de Hidalgo, Tulancingo de Bravo, México
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30
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Bikash CR, Tal-Gan Y. Structure Activity Relationship Study of the XIP Quorum Sensing Pheromone in Streptococcus mutans Reveal Inhibitors of the Competence Regulon. ACS Chem Biol 2020; 15:2833-2841. [PMID: 32946208 DOI: 10.1021/acschembio.0c00650] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The dental cariogenic pathogen Streptococcus mutans coordinates competence for genetic transformation via two peptide pheromones, competence stimulating peptide (CSP) and comX-inducing peptide (XIP). CSP is sensed by the comCDE system and induces competence indirectly, whereas XIP is sensed by the comRS system and induces competence directly. In chemically defined media (CDM), after uptake by oligopeptide permease, XIP interacts with the cytosolic receptor ComR to form the XIP::ComR complex that activates the expression of comX, an alternative sigma factor that initiates the transcription of late-competence genes. In this study, we set out to determine the molecular mechanism of XIP::ComR interaction. To this end, we performed systematic replacement of the amino acid residues in the XIP pheromone and assessed the ability of the mutated analogs to modulate the competence regulon in CDM. We were able to identify structural features that are important to ComR binding and activation. Our structure-activity relationship insights led us to construct multiple XIP-based inhibitors of the comRS pathway. Furthermore, when comCDE and comRS were both stimulated with CSP and XIP, respectively, a lead XIP-based inhibitor was able to maintain the inhibitory activity. Last, phenotypic assays were used to highlight the potential of XIP-based inhibitors to attenuate pathogenicity in S. mutans and to validate the specificity of these compounds to the comRS pathway within the competence regulon. The XIP-based inhibitors developed in this study can be used as lead scaffolds for the design and development of potential therapeutics against S. mutans infections.
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Affiliation(s)
- Chowdhury Raihan Bikash
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada 89557, United States
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada 89557, United States
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31
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Lingeswaran A, Metton C, Henry C, Monnet V, Juillard V, Gardan R. Export of Rgg Quorum Sensing Peptides is Mediated by the PptAB ABC Transporter in Streptococcus Thermophilus Strain LMD-9. Genes (Basel) 2020; 11:genes11091096. [PMID: 32961685 PMCID: PMC7564271 DOI: 10.3390/genes11091096] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/10/2020] [Accepted: 09/17/2020] [Indexed: 12/26/2022] Open
Abstract
In streptococci, intracellular quorum sensing pathways are based on quorum-sensing systems that are responsible for peptide secretion, maturation, and reimport. These peptides then interact with Rgg or ComR transcriptional regulators in the Rap, Rgg, NprR, PlcR, and PrgX (RRNPP) family, whose members are found in Gram-positive bacteria. Short hydrophobic peptides (SHP) interact with Rgg whereas ComS peptides interact with ComR regulators. To date, in Streptococcus thermophilus, peptide secretion, maturation, and extracellular fate have received little attention, even though this species has several (at least five) genes encoding Rgg regulators and one encoding a ComR regulator. We studied pheromone export in this species, focusing our attention on PptAB, which is an exporter of signaling peptides previously identified in Enterococcus faecalis, pathogenic streptococci and Staphylococcus aureus. In the S. thermophilus strain LMD-9, we showed that PptAB controlled three regulation systems, two SHP/Rgg systems (SHP/Rgg1358 and SHP/Rgg1299), and the ComS/ComR system, while using transcriptional fusions and that PptAB helped to produce and export at least three different mature SHPs (SHP1358, SHP1299, and SHP279) peptides while using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Using a deep sequencing approach (RNAseq), we showed that the exporter PptAB, the membrane protease Eep, and the oligopeptide importer Ami controlled the transcription of the genes that were located downstream from the five non-truncated rgg genes as well as few distal genes. This led us to propose that the five non-truncated shp/rgg loci were functional. Only three shp genes were expressed in our experimental condition. Thus, this transcriptome analysis also highlighted the complex interconnected network that exists between SHP/Rgg systems, where a few homologous signaling peptides likely interact with different regulators.
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32
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Kreth J, Merritt J, Pfeifer C, Khajotia S, Ferracane J. Interaction between the Oral Microbiome and Dental Composite Biomaterials: Where We Are and Where We Should Go. J Dent Res 2020; 99:1140-1149. [PMID: 32479134 PMCID: PMC7443996 DOI: 10.1177/0022034520927690] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Dental composites are routinely placed as part of tooth restoration procedures. The integrity of the restoration is constantly challenged by the metabolic activities of the oral microbiome. This activity directly contributes to a less-than-desirable half-life for the dental composite formulations currently in use. Therefore, many new antimicrobial dental composites are being developed to counteract the microbial challenge. To ensure that these materials will resist microbiome-derived degradation, the model systems used for testing antimicrobial activities should be relevant to the in vivo environment. Here, we summarize the key steps in oral microbial colonization that should be considered in clinically relevant model systems. Oral microbial colonization is a clearly defined developmental process that starts with the formation of the acquired salivary pellicle on the tooth surface, a conditioned film that provides the critical attachment sites for the initial colonizers. Further development includes the integration of additional species and the formation of a diverse, polymicrobial mature biofilm. Biofilm development is discussed in the context of dental composites, and recent research is highlighted regarding the effect of antimicrobial composites on the composition of the oral microbiome. Future challenges are addressed, including the potential of antimicrobial resistance development and how this could be counteracted by detailed studies of microbiome composition and gene expression on dental composites. Ultimately, progress in this area will require interdisciplinary approaches to effectively mitigate the inevitable challenges that arise as new experimental bioactive composites are evaluated for potential clinical efficacy. Success in this area could have the added benefit of inspiring other fields in medically relevant materials research, since microbial colonization of medical implants and devices is a ubiquitous problem in the field.
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Affiliation(s)
- J. Kreth
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, USA
| | - J. Merritt
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, USA
| | - C.S. Pfeifer
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - S. Khajotia
- Department of Restorative Sciences, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - J.L. Ferracane
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
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Possible drugs for the treatment of bacterial infections in the future: anti-virulence drugs. J Antibiot (Tokyo) 2020; 74:24-41. [PMID: 32647212 DOI: 10.1038/s41429-020-0344-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/26/2020] [Accepted: 05/29/2020] [Indexed: 12/19/2022]
Abstract
Antibiotic resistance is a global threat that should be urgently resolved. Finding a new antibiotic is one way, whereas the repression of the dissemination of virulent pathogenic bacteria is another. From this point of view, this paper summarizes first the mechanisms of conjugation and transformation, two important processes of horizontal gene transfer, and then discusses the approaches for disarming virulent pathogenic bacteria, that is, virulence factor inhibitors. In contrast to antibiotics, anti-virulence drugs do not impose a high selective pressure on a bacterial population, and repress the dissemination of antibiotic resistance and virulence genes. Disarmed virulence factors make virulent pathogens avirulent bacteria or pathobionts, so that we human will be able to coexist with these disarmed bacteria peacefully.
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Molecular dissection of pheromone selectivity in the competence signaling system ComRS of streptococci. Proc Natl Acad Sci U S A 2020; 117:7745-7754. [PMID: 32198205 DOI: 10.1073/pnas.1916085117] [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] [Indexed: 01/06/2023] Open
Abstract
Competence allows bacteria to internalize exogenous DNA fragments for the acquisition of new phenotypes such as antibiotic resistance or virulence traits. In most streptococci, competence is regulated by ComRS signaling, a system based on the mature ComS pheromone (XIP), which is internalized to activate the (R)RNPP-type ComR sensor by triggering dimerization and DNA binding. Cross-talk analyses demonstrated major differences of selectivity between ComRS systems and raised questions concerning the mechanism of pheromone-sensor recognition and coevolution. Here, we decipher the molecular determinants of selectivity of the closely related ComRS systems from Streptococcus thermophilus and Streptococcus vestibularis Despite high similarity, we show that the divergence in ComR-XIP interaction does not allow reciprocal activation. We perform the structural analysis of the ComRS system from S. vestibularis. Comparison with its ortholog from S. thermophilus reveals an activation mechanism based on a toggle switch involving the recruitment of a key loop by the XIP C terminus. Together with a broad mutational analysis, we identify essential residues directly involved in peptide binding. Notably, we generate a ComR mutant that displays a fully reversed selectivity toward the heterologous pheromone with only five point mutations, as well as other ComR variants featuring XIP bispecificity and/or neofunctionalization for hybrid XIP peptides. We also reveal that a single XIP mutation relaxes the strictness of ComR activation, suggesting fast adaptability of molecular communication phenotypes. Overall, this study is paving the way toward the rational design or directed evolution of artificial ComRS systems for a range of biotechnological and biomedical applications.
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35
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Carvalho G, Fouchet D, Danesh G, Godeux AS, Laaberki MH, Pontier D, Charpentier X, Venner S. Bacterial Transformation Buffers Environmental Fluctuations through the Reversible Integration of Mobile Genetic Elements. mBio 2020; 11:mBio.02443-19. [PMID: 32127449 PMCID: PMC7064763 DOI: 10.1128/mbio.02443-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Horizontal gene transfer (HGT) promotes the spread of genes within bacterial communities. Among the HGT mechanisms, natural transformation stands out as being encoded by the bacterial core genome. Natural transformation is often viewed as a way to acquire new genes and to generate genetic mixing within bacterial populations. Another recently proposed function is the curing of bacterial genomes of their infectious parasitic mobile genetic elements (MGEs). Here, we propose that these seemingly opposing theoretical points of view can be unified. Although costly for bacterial cells, MGEs can carry functions that are at points in time beneficial to bacteria under stressful conditions (e.g., antibiotic resistance genes). Using computational modeling, we show that, in stochastic environments, an intermediate transformation rate maximizes bacterial fitness by allowing the reversible integration of MGEs carrying resistance genes, although these MGEs are costly for host cell replication. Based on this dual function (MGE acquisition and removal), transformation would be a key mechanism for stabilizing the bacterial genome in the long term, and this would explain its striking conservation.IMPORTANCE Natural transformation is the acquisition, controlled by bacteria, of extracellular DNA and is one of the most common mechanisms of horizontal gene transfer, promoting the spread of resistance genes. However, its evolutionary function remains elusive, and two main roles have been proposed: (i) the new gene acquisition and genetic mixing within bacterial populations and (ii) the removal of infectious parasitic mobile genetic elements (MGEs). While the first one promotes genetic diversification, the other one promotes the removal of foreign DNA and thus genome stability, making these two functions apparently antagonistic. Using a computational model, we show that intermediate transformation rates, commonly observed in bacteria, allow the acquisition then removal of MGEs. The transient acquisition of costly MGEs with resistance genes maximizes bacterial fitness in environments with stochastic stress exposure. Thus, transformation would ensure both a strong dynamic of the bacterial genome in the short term and its long-term stabilization.
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Affiliation(s)
- Gabriel Carvalho
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, Villeurbanne, France
| | - David Fouchet
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, Villeurbanne, France
| | - Gonché Danesh
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, Villeurbanne, France
| | - Anne-Sophie Godeux
- CIRI, Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, Villeurbanne, France
- CNRS UMR5308, École Normale Supérieure de Lyon, University of Lyon, Villeurbanne, France
| | - Maria-Halima Laaberki
- CIRI, Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, Villeurbanne, France
- Université de Lyon, VetAgro Sup, Marcy-l'Étoile, France
- CNRS UMR5308, École Normale Supérieure de Lyon, University of Lyon, Villeurbanne, France
| | - Dominique Pontier
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, Villeurbanne, France
| | - Xavier Charpentier
- CIRI, Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, Villeurbanne, France
- CNRS UMR5308, École Normale Supérieure de Lyon, University of Lyon, Villeurbanne, France
| | - Samuel Venner
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, Villeurbanne, France
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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.
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Novel Probiotic Mechanisms of the Oral Bacterium Streptococcus sp. A12 as Explored with Functional Genomics. Appl Environ Microbiol 2019; 85:AEM.01335-19. [PMID: 31420345 DOI: 10.1128/aem.01335-19] [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: 06/12/2019] [Accepted: 08/14/2019] [Indexed: 12/11/2022] Open
Abstract
Health-associated biofilms in the oral cavity are composed of a diverse group of microbial species that can foster an environment that is less favorable for the outgrowth of dental caries pathogens, like Streptococcus mutans A novel oral bacterium, designated Streptococcus A12, was previously isolated from supragingival dental plaque of a caries-free individual and was shown to interfere potently with the growth and virulence properties of S. mutans In this study, we applied functional genomics to begin to identify molecular mechanisms used by A12 to antagonize, and to resist the antagonistic factors of, S. mutans Using bioinformatics, genes that could encode factors that enhance the ability of A12 to compete with S. mutans were identified. Selected genes, designated potential competitive factors (pcf), were deleted. Certain mutant derivatives showed a reduced capacity to compete with S. mutans compared to that of the parental strain. The A12 pcfO mutant lost the ability to inhibit comX -inducing peptide (XIP) signaling by S. mutans, while mutants with changes in the pcfFEG locus were impaired in sensing of, and were more sensitive to, the lantibiotic nisin. Loss of PcfV, annotated as a colicin V biosynthetic protein, resulted in diminished antagonism of S. mutans Collectively, the data provide new insights into the complexities and variety of factors that affect biofilm ecology and virulence. Continued exploration of the genomic and physiological factors that distinguish commensals from truly beneficial members of the oral microbiota will lead to a better understanding of the microbiome and new approaches to promote oral health.IMPORTANCE Advances in defining the composition of health-associated biofilms have highlighted the important role of beneficial species in maintaining health. Comparatively little, however, has been done to address the genomic and physiological bases underlying the probiotic mechanisms of beneficial commensals. In this study, we explored the ability of a novel oral bacterial isolate, Streptococcus A12, to compete with the dental pathogen Streptococcus mutans using various gene products with diverse functions. A12 displayed enhanced competitiveness by (i) disrupting intercellular communication pathways of S. mutans, (ii) sensing and resisting antimicrobial peptides, and (iii) producing factors involved in the production of a putative antimicrobial compound. Research on the probiotic mechanisms employed by Streptococcus A12 is providing essential insights into how beneficial bacteria may help maintain oral health, which will aid in the development of biomarkers and therapeutics that can improve the practice of clinical dentistry.
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Underhill SAM, Shields RC, Burne RA, Hagen SJ. Carbohydrate and PepO control bimodality in competence development by Streptococcus mutans. Mol Microbiol 2019; 112:1388-1402. [PMID: 31403729 DOI: 10.1111/mmi.14367] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2019] [Indexed: 01/17/2023]
Abstract
In Streptococcus mutans, the alternative sigma factor ComX controls entry into genetic competence. Competence stimulating peptide (CSP) induces bimodal expression of comX, with only a fraction of the population becoming transformable. Curiously, the bimodality of comX is affected by peptides in the growth medium and by carbohydrate source. CSP elicits bimodal expression of comX in media rich in small peptides, but CSP elicits no response in defined media lacking small peptides. In addition, growth on certain sugars increases the proportion of the population that activates comX in response to CSP. By investigating the connection between media and comX bimodality, we find evidence for two mechanisms that modulate transcriptional positive feedback in the ComRS system, where comX bimodality originates. We find that the endopeptidase PepO suppresses the ComRS feedback loop, most likely by degrading the XIP/ComS feedback signal. Deletion of pepO eliminates comX bimodality, leading to a unimodal comX response to CSP in both defined and complex media. We also find that CSP stimulates the ComRS feedback system by upregulating comR in a carbohydrate source-dependent fashion. Our data provide mechanistic insight into how S. mutans regulates bimodality and explain the puzzle of growth medium effects on competence induction by CSP.
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Affiliation(s)
- Simon A M Underhill
- Department of Physics, University of Florida, 2001 Museum Road, Gainesville, FL, 32611, USA
| | - Robert C Shields
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL, 32610, USA
| | - Robert A Burne
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL, 32610, USA
| | - Stephen J Hagen
- Department of Physics, University of Florida, 2001 Museum Road, Gainesville, FL, 32611, USA
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Mignolet J, Cerckel G, Damoczi J, Ledesma-Garcia L, Sass A, Coenye T, Nessler S, Hols P. Subtle selectivity in a pheromone sensor triumvirate desynchronizes competence and predation in a human gut commensal. eLife 2019; 8:47139. [PMID: 31433299 PMCID: PMC6703854 DOI: 10.7554/elife.47139] [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: 03/25/2019] [Accepted: 08/06/2019] [Indexed: 11/16/2022] Open
Abstract
Constantly surrounded by kin or alien organisms in nature, eukaryotes and prokaryotes developed various communication systems to coordinate adaptive multi-entity behavior. In complex and overcrowded environments, they require to discriminate relevant signals in a myriad of pheromones to execute appropriate responses. In the human gut commensal Streptococcus salivarius, the cytoplasmic Rgg/RNPP regulator ComR couples competence to bacteriocin-mediated predation. Here, we describe a paralogous sensor duo, ScuR and SarF, which circumvents ComR in order to disconnect these two physiological processes. We highlighted the recurring role of Rgg/RNPP in the production of antimicrobials and designed a robust genetic screen to unveil potent/optimized peptide pheromones. Further mutational and biochemical analyses dissected the modifiable selectivity toward their pheromone and operating sequences at the subtle molecular level. Additionally, our results highlight how we might mobilize antimicrobial molecules while silencing competence in endogenous populations of human microflora and temper gut disorders provoked by bacterial pathogens.
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Affiliation(s)
- Johann Mignolet
- Biochemistry and Genetics of Microorganisms (BGM), Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Louvain-la-Neuve, Belgium.,Syngulon, Seraing, Belgium
| | - Guillaume Cerckel
- Biochemistry and Genetics of Microorganisms (BGM), Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Julien Damoczi
- Biochemistry and Genetics of Microorganisms (BGM), Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Laura Ledesma-Garcia
- Biochemistry and Genetics of Microorganisms (BGM), Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Andrea Sass
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Sylvie Nessler
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Pascal Hols
- Biochemistry and Genetics of Microorganisms (BGM), Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Louvain-la-Neuve, Belgium
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40
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Yehuda A, Slamti L, Malach E, Lereclus D, Hayouka Z. Elucidating the Hot Spot Residues of Quorum Sensing Peptidic Autoinducer PapR by Multiple Amino Acid Replacements. Front Microbiol 2019; 10:1246. [PMID: 31231335 PMCID: PMC6568020 DOI: 10.3389/fmicb.2019.01246] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 05/20/2019] [Indexed: 11/29/2022] Open
Abstract
The quorum sensing (QS) system of Bacillus cereus, an opportunistic human pathogen, utilizes the autoinducing PapR peptide signal that mediates the activation of the pleiotropic virulence regulator PlcR. A set of synthetic 7-mer PapR-derived peptides (PapR7; ADLPFEF) have been shown to inhibit efficiently the PlcR regulon activity and the production of virulence factors, reflected by a loss in hemolytic activity without affecting bacterial growth. Interestingly, these first potent synthetic inhibitors involved D-amino acid or alanine replacements of three amino acids; proline, glutamic acid, and phenylalanine of the heptapeptide PapR. To better understand the role of these three positions in PlcR activity, we report herein the second generation design, synthesis, and characterization of PapR7-derived combinations, alternate double and triple alanine and D-amino acids replacement at these positions. Our findings generate a new set of non-native PapR7-derived peptides that inhibit the PlcR regulon activity and the production of virulence factors. Using the amino acids substitution strategy, we revealed the role of proline and glutamic acid on PlcR regulon activation. Moreover, we demonstrated that the D-Glutamic acid substitution was crucial for the design of stronger PlcR antagonists. These peptides represent potent synthetic inhibitors of B. cereus QS and constitute new and readily accessible chemical tools for the study of the PlcR system. Our method might be applied to other quorum sensing systems to design new anti-virulence agents.
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Affiliation(s)
- Avishag Yehuda
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Leyla Slamti
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Einav Malach
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Didier Lereclus
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Zvi Hayouka
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, Israel
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Kaspar JR, Walker AR. Expanding the Vocabulary of Peptide Signals in Streptococcus mutans. Front Cell Infect Microbiol 2019; 9:194. [PMID: 31245303 PMCID: PMC6563777 DOI: 10.3389/fcimb.2019.00194] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 05/21/2019] [Indexed: 12/18/2022] Open
Abstract
Streptococci, including the dental pathogen Streptococcus mutans, undergo cell-to-cell signaling that is mediated by small peptides to control critical physiological functions such as adaptation to the environment, control of subpopulation behaviors and regulation of virulence factors. One such model pathway is the regulation of genetic competence, controlled by the ComRS signaling system and the peptide XIP. However, recent research in the characterization of this pathway has uncovered novel operons and peptides that are intertwined into its regulation. These discoveries, such as cell lysis playing a critical role in XIP release and importance of bacterial self-sensing during the signaling process, have caused us to reevaluate previous paradigms and shift our views on the true purpose of these signaling systems. The finding of new peptides such as the ComRS inhibitor XrpA and the peptides of the RcrRPQ operon also suggests there may be more peptides hidden in the genomes of streptococci that could play critical roles in the physiology of these organisms. In this review, we summarize the recent findings in S. mutans regarding the integration of other circuits into the ComRS signaling pathway, the true mode of XIP export, and how the RcrRPQ operon controls competence activation. We also look at how new technologies can be used to re-annotate the genome to find new open reading frames that encode peptide signals. Together, this summary of research will allow us to reconsider how we perceive these systems to behave and lead us to expand our vocabulary of peptide signals within the genus Streptococcus.
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Affiliation(s)
- Justin R. Kaspar
- Department of Oral Biology, University of Florida, Gainesville, FL, United States
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42
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Mignolet J, Fontaine L, Sass A, Nannan C, Mahillon J, Coenye T, Hols P. Circuitry Rewiring Directly Couples Competence to Predation in the Gut Dweller Streptococcus salivarius. Cell Rep 2019; 22:1627-1638. [PMID: 29444418 DOI: 10.1016/j.celrep.2018.01.055] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 12/05/2017] [Accepted: 01/18/2018] [Indexed: 02/03/2023] Open
Abstract
Small distortions in transcriptional networks might lead to drastic phenotypical changes, especially in cellular developmental programs such as competence for natural transformation. Here, we report a pervasive circuitry rewiring for competence and predation interplay in commensal streptococci. Canonically, in streptococci paradigms such as Streptococcus pneumoniae and Streptococcus mutans, the pheromone-based two-component system BlpRH is a central node that orchestrates the production of antimicrobial compounds (bacteriocins) and incorporates signal from the competence activation cascade. However, the human commensal Streptococcus salivarius does not contain a functional BlpRH pair, while the competence signaling system ComRS directly couples bacteriocin production and competence commitment. This network shortcut might underlie an optimal adaptation against microbial competitors and explain the high prevalence of S. salivarius in the human digestive tract. Moreover, the broad spectrum of bacteriocin activity against pathogenic bacteria showcases the commensal and genetically tractable S. salivarius species as a user-friendly model for competence and bacterial predation.
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Affiliation(s)
- Johann Mignolet
- Biochemistry, Biophysics, and Genetics of Microorganisms (BBGM), Institute of Life Sciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium.
| | - Laetitia Fontaine
- Biochemistry, Biophysics, and Genetics of Microorganisms (BBGM), Institute of Life Sciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Andrea Sass
- Laboratory of Pharmaceutical Microbiology, Ghent University, 9000 Ghent, Belgium
| | - Catherine Nannan
- Laboratory of Food and Environmental Microbiology, Earth and Life Institute, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Jacques Mahillon
- Laboratory of Food and Environmental Microbiology, Earth and Life Institute, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, 9000 Ghent, Belgium
| | - Pascal Hols
- Biochemistry, Biophysics, and Genetics of Microorganisms (BBGM), Institute of Life Sciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium.
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43
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Wang X, Cai J, Shang N, Zhu L, Shao N, Dong X, Tong H. The carbon catabolite repressor CcpA mediates optimal competence development in Streptococcus oligofermentans through post-transcriptional regulation. Mol Microbiol 2019; 112:552-568. [PMID: 31074889 DOI: 10.1111/mmi.14274] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2019] [Indexed: 11/28/2022]
Abstract
Natural transformation increases the genetic diversity of bacteria, but is costly and must be strictly controlled. We previously found that deletion of ccpA, a key regulator of carbon catabolite repression (CCR), reduced transformation efficiency of Streptococcus oligofermentans, the current work further investigated the regulatory mechanisms of CcpA. The competence operon comCDE is subjected to basal and autoregulatory transcription. A luciferase reporter detected a transcriptional readthrough (TRT) from the upstream tRNAArg into the comCDE operon, which was induced by L -arginine. Insertion of the Escherichia coli T1T2 terminator downstream of tRNAArg abolished TRT, and reduced the basal comCDE transcription by 77% and also the transformation efficiency. Deletion of ccpA increased tRNAArg TRT and tRNAArg -comCDE polycistronic transcript by twofold. An in vitro transcription assay determined that CcpA promoted the transcription termination of tRNAArg TRT, and RNA EMSA and SPR assays detected equal binding affinity of CcpA to both the RNA and DNA of tRNAArg . These results indicate that CcpA controls the basal comCDE transcription by post-transcriptional actions. Overexpression of comDE or its phospho-mimicking mutant comDED58E reduced transformation efficiency, indicating that excessive ComE impairs competence development. CCR-regulated competence was further confirmed by higher tRNAArg TRT but lower transformation efficiency in galactose than in glucose.
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Affiliation(s)
- Xinhui Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing, 100101, China.,University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing, 100049, China
| | - Jun Cai
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing, 100101, China
| | - Nan Shang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing, 100101, China
| | - Lin Zhu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing, 100101, China
| | - Nana Shao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing, 100101, China
| | - Xiuzhu Dong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing, 100101, China.,University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing, 100049, China
| | - Huichun Tong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing, 100101, China.,University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing, 100049, China
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44
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Stingl K, Koraimann G. Prokaryotic Information Games: How and When to Take up and Secrete DNA. Curr Top Microbiol Immunol 2019. [PMID: 29536355 DOI: 10.1007/978-3-319-75241-9_3] [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: 02/07/2023]
Abstract
Besides transduction via bacteriophages natural transformation and bacterial conjugation are the most important mechanisms driving bacterial evolution and horizontal gene spread. Conjugation systems have evolved in eubacteria and archaea. In Gram-positive and Gram-negative bacteria, cell-to-cell DNA transport is typically facilitated by a type IV secretion system (T4SS). T4SSs also mediate uptake of free DNA in Helicobacter pylori, while most transformable bacteria use a type II secretion/type IV pilus system. In this chapter, we focus on how and when bacteria "decide" that such a DNA transport apparatus is to be expressed and assembled in a cell that becomes competent. Development of DNA uptake competence and DNA transfer competence is driven by a variety of stimuli and often involves intricate regulatory networks leading to dramatic changes in gene expression patterns and bacterial physiology. In both cases, genetically homogeneous populations generate a distinct subpopulation that is competent for DNA uptake or DNA transfer or might uniformly switch into competent state. Phenotypic conversion from one state to the other can rely on bistable genetic networks that are activated stochastically with the integration of external signaling molecules. In addition, we discuss principles of DNA uptake processes in naturally transformable bacteria and intend to understand the exceptional use of a T4SS for DNA import in the gastric pathogen H. pylori. Realizing the events that trigger developmental transformation into competence within a bacterial population will eventually help to create novel and effective therapies against the transmission of antibiotic resistances among pathogens.
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Affiliation(s)
- Kerstin Stingl
- National Reference Laboratory for Campylobacter, Department Biological Safety, Federal Institute for Risk Assessment (BfR), Diedersdorfer Weg 1, 12277, Berlin, Germany.
| | - Günther Koraimann
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010, Graz, Austria.
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45
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Hols P, Ledesma-García L, Gabant P, Mignolet J. Mobilization of Microbiota Commensals and Their Bacteriocins for Therapeutics. Trends Microbiol 2019; 27:690-702. [PMID: 30987817 DOI: 10.1016/j.tim.2019.03.007] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/12/2019] [Accepted: 03/19/2019] [Indexed: 01/21/2023]
Abstract
With the specter of resurgence of pathogens due to the propagation of antibiotic-resistance genes, innovative antimicrobial strategies are needed. In this review, we summarize the beneficial aspects of bacteriocins, a set of miscellaneous peptide-based bacterium killers, compared with classical antibiotics, and emphasize their use in cocktails to curb the emergence of new resistance. We highlight that their prey spectrum, their molecular malleability, and their multiple modes of production might lead to specific and personalized treatments to prevent systemic disorders. Complementarily, we discuss how we might exploit prevailing bacterial commensals, such as Streptococcus salivarius, and deliberately mobilize their bacteriocin arsenal 'on site' to cure multiresistant infections or finely reshape the endogenous microbiota for prophylaxis purposes.
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Affiliation(s)
- Pascal Hols
- Biochemistry and Genetics of Microorganisms (BGM), Louvain Institute of Biomolecular Science and Technology (LIBST), UCLouvain, 1348 Louvain-la-Neuve, Belgium
| | - Laura Ledesma-García
- Biochemistry and Genetics of Microorganisms (BGM), Louvain Institute of Biomolecular Science and Technology (LIBST), UCLouvain, 1348 Louvain-la-Neuve, Belgium
| | - Philippe Gabant
- Syngulon, rue du Bois Saint-Jean 15/1, 4102, Seraing, Belgium
| | - Johann Mignolet
- Biochemistry and Genetics of Microorganisms (BGM), Louvain Institute of Biomolecular Science and Technology (LIBST), UCLouvain, 1348 Louvain-la-Neuve, Belgium; Syngulon, rue du Bois Saint-Jean 15/1, 4102, Seraing, Belgium.
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46
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Hamilos DL. Biofilm Formations in Pediatric Respiratory Tract Infection Part 2: Mucosal Biofilm Formation by Respiratory Pathogens and Current and Future Therapeutic Strategies to Inhibit Biofilm Formation or Eradicate Established Biofilm. Curr Infect Dis Rep 2019; 21:8. [DOI: 10.1007/s11908-019-0657-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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47
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Bedoya-Correa CM, Rincón Rodríguez RJ, Parada-Sanchez MT. Genomic and phenotypic diversity of Streptococcus mutans. J Oral Biosci 2019; 61:22-31. [DOI: 10.1016/j.job.2018.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/29/2018] [Accepted: 11/05/2018] [Indexed: 02/03/2023]
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48
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Junges R, Salvadori G, Chen T, Morrison DA, Petersen FC. Hidden Gems in the Transcriptome Maps of Competent Streptococci. Front Mol Biosci 2019; 5:116. [PMID: 30662898 PMCID: PMC6328492 DOI: 10.3389/fmolb.2018.00116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 12/11/2018] [Indexed: 11/22/2022] Open
Abstract
Natural transformation is regarded as an important mechanism in bacteria that allows for adaptation to different environmental stressors by ensuring genome plasticity. Since the discovery of this phenomenon in Streptococcus pneumoniae, remarkable progress has been made in the understanding of the molecular mechanisms and pathways coordinating this process. Recently, the advent of high-throughput sequencing allows the posing of questions that address the system at a larger scale but also allow for the creation of high-resolution maps of transcription. Thus, while much is already known about genetic competence in streptococci, recent studies continue to reveal intricate novel regulation pathways and components. In this perspective article, we highlight the use of transcriptional profiling and mapping as a valuable resource in the identification and characterization of “hidden gems” pertinent to the natural transformation system. Such strategies have recently been employed in a variety of different species. In S. mutans, for example, genome editing combined with the power of promoter mapping and RNA-Seq allowed for the identification of a link between the ComCDE and the ComRS systems, a ComR positive feedback loop mediated by SigX, and the XrpA peptide, encoded within sigX, which inhibits competence. In S. pneumoniae, a novel member of the competence regulon termed BriC was found to be directly under control of ComE and to promote biofilm formation and nasopharyngeal colonization but not competence. Together these new technologies enable us to discover new links and to revisit old pathways in the compelling study of natural genetic transformation.
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Affiliation(s)
- Roger Junges
- Faculty of Dentistry, Institute of Oral Biology, University of Oslo, Oslo, Norway
| | - Gabriela Salvadori
- Faculty of Dentistry, Institute of Oral Biology, University of Oslo, Oslo, Norway
| | - Tsute Chen
- Department of Microbiology, The Forsyth Institute, Cambridge, MA, United States
| | - Donald A Morrison
- Department of Biological Sciences, College of Liberal Arts and Sciences, University of Illinois at Chicago, Chicago, IL, United States
| | - Fernanda C Petersen
- Faculty of Dentistry, Institute of Oral Biology, University of Oslo, Oslo, Norway
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Abstract
With the application of increasingly advanced "omics" technologies to the study of our resident oral microbiota, the presence of a defined, health-associated microbial community has been recognized. Within this community, sanguinis-group streptococci, comprising the closely related Streptococcus sanguinis and Streptococcus gordonii, together with Streptococcus parasanguinis, often predominate. Their ubiquitous and abundant nature reflects the evolution of these bacteria as highly effective colonizers of the oral cavity. Through interactions with host tissues and other microbes, and the capacity to readily adapt to prevailing environmental conditions, sanguinis-group streptococci are able to shape accretion of the oral plaque biofilm and promote development of a microbial community that exists in harmony with its host. Nonetheless, upon gaining access to the blood stream, those very same colonization capabilities can confer upon sanguinis-group streptococci the ability to promote systemic disease. This article focuses on the role of sanguinis-group streptococci as the commensurate commensals, highlighting those aspects of their biology that enable the coordination of health-associated biofilm development. This includes the molecular mechanisms, both synergistic and antagonistic, that underpin adhesion to substrata, intercellular communication, and polymicrobial community formation. As our knowledge of these processes advances, so will the opportunities to exploit this understanding for future development of novel strategies to control oral and extraoral disease.
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Affiliation(s)
- Angela Nobbs
- Bristol Dental School, University of Bristol, Bristol, United Kingdom
| | - Jens Kreth
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR 97239
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Intensive targeting of regulatory competence genes by transposable elements in streptococci. Mol Genet Genomics 2018; 294:531-548. [DOI: 10.1007/s00438-018-1507-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/21/2018] [Indexed: 10/27/2022]
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