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Prudhomme M, Johnston CHG, Soulet AL, Boyeldieu A, De Lemos D, Campo N, Polard P. Pneumococcal competence is a populational health sensor driving multilevel heterogeneity in response to antibiotics. Nat Commun 2024; 15:5625. [PMID: 38987237 PMCID: PMC11237056 DOI: 10.1038/s41467-024-49853-2] [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: 12/14/2023] [Accepted: 06/21/2024] [Indexed: 07/12/2024] Open
Abstract
Competence for natural transformation is a central driver of genetic diversity in bacteria. In the human pathogen Streptococcus pneumoniae, competence exhibits a populational character mediated by the stress-induced ComABCDE quorum-sensing (QS) system. Here, we explore how this cell-to-cell communication mechanism proceeds and the functional properties acquired by competent cells grown under lethal stress. We show that populational competence development depends on self-induced cells stochastically emerging in response to stresses, including antibiotics. Competence then propagates through the population from a low threshold density of self-induced cells, defining a biphasic Self-Induction and Propagation (SI&P) QS mechanism. We also reveal that a competent population displays either increased sensitivity or improved tolerance to lethal doses of antibiotics, dependent in the latter case on the competence-induced ComM division inhibitor. Remarkably, these surviving competent cells also display an altered transformation potential. Thus, the unveiled SI&P QS mechanism shapes pneumococcal competence as a health sensor of the clonal population, promoting a bet-hedging strategy that both responds to and drives cells towards heterogeneity.
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Affiliation(s)
- Marc Prudhomme
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), UMR5100, Centre de Biologie Intégrative (CBI), Centre Nationale de la Recherche Scientifique (CNRS), Toulouse, France
- Université Paul Sabatier (Toulouse III), Toulouse, France
| | - Calum H G Johnston
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), UMR5100, Centre de Biologie Intégrative (CBI), Centre Nationale de la Recherche Scientifique (CNRS), Toulouse, France
- Université Paul Sabatier (Toulouse III), Toulouse, France
| | - Anne-Lise Soulet
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), UMR5100, Centre de Biologie Intégrative (CBI), Centre Nationale de la Recherche Scientifique (CNRS), Toulouse, France
- Université Paul Sabatier (Toulouse III), Toulouse, France
| | - Anne Boyeldieu
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), UMR5100, Centre de Biologie Intégrative (CBI), Centre Nationale de la Recherche Scientifique (CNRS), Toulouse, France
- Université Paul Sabatier (Toulouse III), Toulouse, France
| | - David De Lemos
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), UMR5100, Centre de Biologie Intégrative (CBI), Centre Nationale de la Recherche Scientifique (CNRS), Toulouse, France
- Université Paul Sabatier (Toulouse III), Toulouse, France
| | - Nathalie Campo
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), UMR5100, Centre de Biologie Intégrative (CBI), Centre Nationale de la Recherche Scientifique (CNRS), Toulouse, France
- Université Paul Sabatier (Toulouse III), Toulouse, France
| | - Patrice Polard
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), UMR5100, Centre de Biologie Intégrative (CBI), Centre Nationale de la Recherche Scientifique (CNRS), Toulouse, France.
- Université Paul Sabatier (Toulouse III), Toulouse, France.
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2
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Barbey C, Latour X. Molecular Mechanisms of Bacterial Communication and Their Biocontrol. Int J Mol Sci 2024; 25:5443. [PMID: 38791481 PMCID: PMC11121524 DOI: 10.3390/ijms25105443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024] Open
Abstract
A bacterium's ability to colonize and adapt to an ecological niche is highly dependent on its capacity to perceive and analyze its environment and its ability to interact with its hosts and congeners [...].
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Affiliation(s)
- Corinne Barbey
- Laboratory of Bacterial Communication and Anti-Infectious Strategies (CBSA UR4312, Formerly LMSM EA4312), University Rouen Normandie, Université Caen Normandie, Normandie University, F-76000 Rouen, France;
- Research Federation NORVEGE Fed4277, Normandie University, F-76000 Rouen, France
- International Research Federation NOR-SEVE, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - Xavier Latour
- Laboratory of Bacterial Communication and Anti-Infectious Strategies (CBSA UR4312, Formerly LMSM EA4312), University Rouen Normandie, Université Caen Normandie, Normandie University, F-76000 Rouen, France;
- Research Federation NORVEGE Fed4277, Normandie University, F-76000 Rouen, France
- International Research Federation NOR-SEVE, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
- Biocontrol and Biostimulation for Agroecology Association (ABBA), F-75000 Paris, France
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3
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You J, Wang Y, Wang K, Du Y, Zhang X, Zhang X, Yang T, Pan X, Rao Z. Utilizing 5' UTR Engineering Enables Fine-Tuning of Multiple Genes within Operons to Balance Metabolic Flux in Bacillus subtilis. BIOLOGY 2024; 13:277. [PMID: 38666889 PMCID: PMC11047901 DOI: 10.3390/biology13040277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/10/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024]
Abstract
The application of synthetic biology tools to modulate gene expression to increase yield has been thoroughly demonstrated as an effective and convenient approach in industrial production. In this study, we employed a high-throughput screening strategy to identify a 5' UTR sequence from the genome of B. subtilis 168. This sequence resulted in a 5.8-fold increase in the expression level of EGFP. By utilizing the 5' UTR sequence to overexpress individual genes within the rib operon, it was determined that the genes ribD and ribAB serve as rate-limiting enzymes in the riboflavin synthesis pathway. Constructing a 5' UTR library to regulate EGFP expression resulted in a variation range in gene expression levels exceeding 100-fold. Employing the same 5' UTR library to regulate the expression of EGFP and mCherry within the operon led to a change in the expression ratio of these two genes by over 10,000-fold. So, employing a 5' UTR library to modulate the expression of the rib operon gene and construct a synthetic rib operon resulted in a 2.09-fold increase in riboflavin production. These results indicate that the 5' UTR sequence identified and characterized in this study can serve as a versatile synthetic biology toolkit for achieving complex metabolic network reconstruction. This toolkit can facilitate the fine-tuning of gene expression to produce target products.
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Affiliation(s)
- Jiajia You
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
- Yixing Institute of Food and Biotechnology Co., Ltd., Yixing 214200, China
| | - Yifan Wang
- Department of Food Science and Technology, Texas A & M University, College Station, TX 77843, USA;
| | - Kang Wang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Yuxuan Du
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Xiaoling Zhang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Xian Zhang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Taowei Yang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Xuewei Pan
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Zhiming Rao
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
- Yixing Institute of Food and Biotechnology Co., Ltd., Yixing 214200, China
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4
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Vinodhini V, Kavitha M. Deciphering agr quorum sensing in Staphylococcus aureus: insights and therapeutic prospects. Mol Biol Rep 2024; 51:155. [PMID: 38252331 DOI: 10.1007/s11033-023-08930-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 10/10/2023] [Indexed: 01/23/2024]
Abstract
The emergence of superbugs like methicillin-resistant Staphylococcus aureus exposed the limitations of treating microbial infections using antibiotics. At present, the discovery of novel and convincing therapeutic methods are being executed increasingly as possible substitutes to conventional antibiotic therapies. The quorum sensing helps Staphylococcus aureus become more viable through their signaling mechanisms. In recent years, targeting the prominent factors of quorum sensing has obtained remarkable attention as a futuristic approach to dealing with bacterial pathogenicity. The standard antibiotic therapy intends to inhibit the organism by targeting specific molecules and afford a chance for the evolution of antibiotic resistance. This prompts the development of novel therapeutic strategies like inhibiting quorum sensing that can limit bacterial virulence by decreasing the selective pressure, thereby restricting antibiotic resistance evolution. This review furnishes new insights into the accessory gene regulator quorum sensing in Staphylococcus aureus and its inhibition by targeting the genes that regulate the operon. Further, this review comprehensively explores the inhibitors reported up to date and their specific targets and discusses their potentially ineffective alternative therapy against methicillin-resistant Staphylococcus aureus.
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Affiliation(s)
- V Vinodhini
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - M Kavitha
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India.
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Danevčič T, Spacapan M, Dragoš A, Kovács ÁT, Mandic-Mulec I. DegQ is an important policing link between quorum sensing and regulated adaptative traits in Bacillus subtilis. Microbiol Spectr 2023; 11:e0090823. [PMID: 37676037 PMCID: PMC10581247 DOI: 10.1128/spectrum.00908-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 07/26/2023] [Indexed: 09/08/2023] Open
Abstract
Quorum sensing (QS) is a widespread bacterial communication system that controls important adaptive traits in a cell density-dependent manner. However, mechanisms by which QS-regulated traits are linked within the cell and mechanisms by which these links affect adaptation are not well understood. In this study, Bacillus subtilis was used as a model bacterium to investigate the link between the ComQXPA QS system, DegQ, surfactin and protease production in planktonic and biofilm cultures. The work tests two alternative hypotheses predicting that hypersensitivity of the QS signal-deficient mutant (comQ::kan) to exogenously added ComX, resulting in increased surfactin production, is linked to an additional genetic locus, or alternatively, to overexpression of the ComX receptor ComP. Results are in agreement with the first hypothesis and show that the P srfAA hypersensitivity of the comQ::kan mutant is linked to a 168 strain-specific mutation in the P degQ region. Hence, the markerless ΔcomQ mutant lacking this mutation is not overresponsive to ComX. Such hyper-responsiveness is specific for the P srfAA and not detected in another ComX-regulated promoter, the P aprE , which is under the positive control by DegQ. Our results suggest that DegQ by exerting differential effect on P srfAA and P aprE acts as a policing mechanism and the intracellular link, which guards the cell from an overinvestment into surfactin production. IMPORTANCE DegQ levels are known to regulate surfactin synthesis and extracellular protease production, and DegQ is under the control of the ComX-dependent QS. DegQ also serves as an important policing link between these QS-regulated processes, preventing overinvestment in these costly processes. This work highlights the importance of DegQ, which acts as the intracellular link between ComX production and the response by regulating extracellular degradative enzyme synthesis and surfactin production.
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Affiliation(s)
- Tjaša Danevčič
- Department of Microbiology, Chair of microbial ecology and physiology, University of Ljubljana, Biotechnical Faculty, Ljubljana, Slovenia
| | - Mihael Spacapan
- Department of Microbiology, Chair of microbial ecology and physiology, University of Ljubljana, Biotechnical Faculty, Ljubljana, Slovenia
| | - Anna Dragoš
- Department of Microbiology, Chair of microbial ecology and physiology, University of Ljubljana, Biotechnical Faculty, Ljubljana, Slovenia
| | - Ákos T. Kovács
- Department of Biotechnology and Biomedicine, Bacterial Interactions and Evolution Group, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Ines Mandic-Mulec
- Department of Microbiology, Chair of microbial ecology and physiology, University of Ljubljana, Biotechnical Faculty, Ljubljana, Slovenia
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Bareia T, Pollak S, Guler P, Puyesky S, Eldar A. Major distinctions between the two oligopeptide permease systems of Bacillus subtilis with respect to signaling, development and evolutionary divergence. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001382. [PMID: 37755230 PMCID: PMC10569065 DOI: 10.1099/mic.0.001382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 08/02/2023] [Indexed: 09/28/2023]
Abstract
Oligopeptide-permeases (Opps) are used by bacteria to import short peptides. In addition to their metabolic benefit, imported short peptides are used in many Gram-positive bacteria as signalling molecules of the RRNPP super-family of quorum-sensing systems, making Opps an integral part of cell–cell communication. In some Gram-positive bacteria there exist multiple Opps and the relative importance of those to RRNPP quorum sensing are not fully clear. Specifically, in Bacillus subtilis , the Gram-positive model species, there exist two homologous oligopeptide permeases named Opp and App. Previous work showed that the App system is mutated in lab strain 168 and its recovery partially complements an Opp mutation for several developmental processes. Yet, the nature of the impact of App on signalling and development in wild-type strains, where both permeases are active was not studied. Here we re-examine the impact of the two permease systems. We find that App has a minor contribution to biofilm formation, surfactin production and phage infection compared to the effect of Opp. This reduced effect is also reflected in its lower ability to import the signals of four different Rap-Phr RRNPP systems. Further analysis of the App system revealed that, unlike Opp, some App genes have undergone horizontal transfer, resulting in two distinct divergent alleles of this system in B. subtilis strains. We found that both alleles were substantially better adapted than the Opp system to import an exogenous RRNPP signal of the Bacillus cereus group PlcR-PapR system. In summary, we find that the App system has only a minor role in signalling but may still be crucial for the import of other peptides.
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Affiliation(s)
- Tasneem Bareia
- Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel
- Present address: Department of Plant & Environmental Sciences, Faculty of Biochemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Shaul Pollak
- Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel
- Present address: Division of Microbial Ecology, Centre for Microbiology and Environmental Science, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Polina Guler
- Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel
| | - Shani Puyesky
- Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel
| | - Avigdor Eldar
- Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel
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Lu Q, Pan K, Liu J, Zhang T, Yang L, Yi X, Zhong G. Quorum sensing system effectively enhances DegU-mediated degradation of pyrethroids by Bacillus subtilis. JOURNAL OF HAZARDOUS MATERIALS 2023; 455:131586. [PMID: 37178530 DOI: 10.1016/j.jhazmat.2023.131586] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/24/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023]
Abstract
The contamination of the natural environment is a growing concern that threatens all life forms, including microorganisms. Bacteria protect themselves by initiating quorum sensing (QS), a bacterial cell-cell communication, to generate adaptive responses to these pollutants. Bacillus subtilis has a typical QS ComQXPA system that regulates the phosphorylation of the transcription factor DegU (DegU-P), and thus can mediate the expression of various downstream genes under different stress conditions. Herein, we found that cesB, a gene of Bacillus subtilis 168, plays a key role in pyrethroid degradation, and cesB-mediated degradation could be enhanced by coordinating with the ComX communication system. Using β-cypermethrin (β-CP) as a paradigm, we demonstrated that DegU-P increased upon exposure to β-CP, thus facilitating β-CP degradation by binding to the upstream regulatory regions of cesB, leading to the activation of the expression of cesB. Further, we showed that the expression of different levels of phosphorylated DegU in a degU deletion strain resulted in varying degrees of β-CP degradation efficiency, with phosphorylated DegUH12L achieving 78.39% degradation efficiency on the first day, surpassing the 56.27% degradation efficiency in the wild type strain. Consequently, based on the conserved regulatory mechanism of ComQXPA system, we propose that DegU-P-dependent regulation serves as a conserved defense mechanism owing to its ability to fine-tune the expression of genes involved in the degradation of pollutants upon exposure to different pesticides.
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Affiliation(s)
- Qiqi Lu
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, China; Key Laboratory of Crop Integrated Pest Management in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou, China; Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China
| | - Keqing Pan
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, China; Key Laboratory of Crop Integrated Pest Management in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou, China; Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China
| | - Jie Liu
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, China; Key Laboratory of Crop Integrated Pest Management in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou, China; Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China
| | - Tong Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Liying Yang
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, China; Key Laboratory of Crop Integrated Pest Management in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou, China; Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China
| | - Xin Yi
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, China; Key Laboratory of Crop Integrated Pest Management in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou, China; Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China.
| | - Guohua Zhong
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, China; Key Laboratory of Crop Integrated Pest Management in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou, China; Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China.
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8
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You Z, Li J, Wang Y, Wu D, Li F, Song H. Advances in mechanisms and engineering of electroactive biofilms. Biotechnol Adv 2023; 66:108170. [PMID: 37148984 DOI: 10.1016/j.biotechadv.2023.108170] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 03/22/2023] [Accepted: 05/02/2023] [Indexed: 05/08/2023]
Abstract
Electroactive biofilms (EABs) are electroactive microorganisms (EAMs) encased in conductive polymers that are secreted by EAMs and formed by the accumulation and cross-linking of extracellular polysaccharides, proteins, nucleic acids, lipids, and other components. EABs are present in the form of multicellular aggregates and play a crucial role in bioelectrochemical systems (BESs) for diverse applications, including biosensors, microbial fuel cells for renewable bioelectricity production and remediation of wastewaters, and microbial electrosynthesis of valuable chemicals. However, naturally occurred EABs are severely limited owing to their low electrical conductivity that seriously restrict the electron transfer efficiency and practical applications. In the recent decade, synthetic biology strategies have been adopted to elucidate the regulatory mechanisms of EABs, and to enhance the formation and electrical conductivity of EABs. Based on the formation of EABs and extracellular electron transfer (EET) mechanisms, the synthetic biology-based engineering strategies of EABs are summarized and reviewed as follows: (i) Engineering the structural components of EABs, including strengthening the synthesis and secretion of structural elements such as polysaccharides, eDNA, and structural proteins, to improve the formation of biofilms; (ii) Enhancing the electron transfer efficiency of EAMs, including optimizing the distribution of c-type cytochromes and conducting nanowire assembly to promote contact-based EET, and enhancing electron shuttles' biosynthesis and secretion to promote shuttle-mediated EET; (iii) Incorporating intracellular signaling molecules in EAMs, including quorum sensing systems, secondary messenger systems, and global regulatory systems, to increase the electron transfer flux in EABs. This review lays a foundation for the design and construction of EABs for diverse BES applications.
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Affiliation(s)
- Zixuan You
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Jianxun Li
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100093, China
| | - Yuxuan Wang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Deguang Wu
- Department of Brewing Engineering, Moutai Institute, Luban Ave, Renhuai 564507, Guizhou, PR China
| | - Feng Li
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
| | - Hao Song
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
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Xu K, Tong Y, Li Y, Tao J, Rao S, Li J, Zhou J, Liu S. Autoinduction AND Gate Inhibits Cell Lysis to Enhance Protein Production in Bacillus subtilis Controlled by Population Density and Cell Physiological State. ACS Synth Biol 2023; 12:842-851. [PMID: 36881491 DOI: 10.1021/acssynbio.2c00624] [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: 03/08/2023]
Abstract
The extracellular protease-deficient strain Bacillus subtilis WB600 is commonly used as a chassis cell for the production of industrial proteins. However, B. subtilis WB600 exhibits an increased susceptibility to cell lysis and a reduction in biomass. Inhibition of cell lysis by knocking out lytic genes will impair physiological function. Here, we dynamically inhibited cell lysis in B. subtilis WB600 to balance the impairment of physiological function with the accumulation of biomass. First, the inducible protein degradation systems (IPDSs) were constructed and used to investigate the effects of inhibiting cell lysis on biomass, cell morphology, and protein production at different times (using pullulanase as a test). The highest pullulanase activity was obtained at 20 h of inhibiting cell lysis, 184.8 U/mL, which was 44% higher than the activity of B. subtilis WB600. Then, to avoid addition of inducers, we introduced orthogonal quorum sensing and constructed autoinduction protein degradation systems (AIPDSs). The optimized AIPDS showed similar pullulanase activity to the optimal IPDS (20 h), 181.3 U/mL. Next, we constructed dual-signal input autoinduction protein degradation systems (DSI-AIPDSs) via AND gate to further address two deficiencies of AIPDS, one-time activation and damage to new cells. These DSI-AIPDSs were controlled by quorum sensing and stationary phase promoters that respond to population density and single-cell physiological state, respectively. Finally, the OD600 and pullulanase activity of the strain with optimal DSI-AIPDS were 51% and 115% higher than those of B. subtilis WB600 in pullulanase production, respectively. We provided a B. subtilis chassis strain with considerable potential for biomass accumulation and enhanced protein production.
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Affiliation(s)
- Kuidong Xu
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China.,Science Center for Future Foods, Jiangnan University, Wuxi 214122, China.,Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
| | - Yi Tong
- National Engineering Research Center for Corn Deep Processing, Jilin COFCO Biochemical Co. Ltd., Changchun 130033, China
| | - Yi Li
- National Engineering Research Center for Corn Deep Processing, Jilin COFCO Biochemical Co. Ltd., Changchun 130033, China
| | - Jin Tao
- National Engineering Research Center for Corn Deep Processing, Jilin COFCO Biochemical Co. Ltd., Changchun 130033, China
| | - Shengqi Rao
- College of Food Science and Engineering, Yangzhou University, Yangzhou, Jiangsu 214122, China
| | - Jianghua Li
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China.,School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
| | - Jingwen Zhou
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China.,Science Center for Future Foods, Jiangnan University, Wuxi 214122, China.,Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
| | - Song Liu
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China.,Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
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10
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Dang Z, Gao M, Wang L, Wu J, Guo Y, Zhu Z, Huang H, Kang G. Synthetic bacterial therapies for intestinal diseases based on quorum- sensing circuits. Biotechnol Adv 2023; 65:108142. [PMID: 36977440 DOI: 10.1016/j.biotechadv.2023.108142] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 03/22/2023] [Accepted: 03/24/2023] [Indexed: 03/28/2023]
Abstract
Bacterial therapy has become a key strategy against intestinal infectious diseases in recent years. Moreover, regulating the gut microbiota through traditional fecal microbiota transplantation and supplementation of probiotics faces controllability, efficacy, and safety challenges. The infiltration and emergence of synthetic biology and microbiome provide an operational and safe treatment platform for live bacterial biotherapies. Synthetic bacterial therapy can artificially manipulate bacteria to produce and deliver therapeutic drug molecules. This method has the advantages of solid controllability, low toxicity, strong therapeutic effects, and easy operation. As an essential tool for dynamic regulation in synthetic biology, quorum sensing (QS) has been widely used for designing complex genetic circuits to control the behavior of bacterial populations and achieve predefined goals. Therefore, QS-based synthetic bacterial therapy might become a new direction for the treatment of diseases. The pre-programmed QS genetic circuit can achieve a controllable production of therapeutic drugs on particular ecological niches by sensing specific signals released from the digestive system in pathological conditions, thereby realizing the integration of diagnosis and treatment. Based on this as well as the modular idea of synthetic biology, QS-based synthetic bacterial therapies are divided into an environmental signal sensing module (senses gut disease physiological signals), a therapeutic molecule producing module (plays a therapeutic role against diseases), and a population behavior regulating module (QS system). This review article summarized the structure and function of these three modules and discussed the rational design of QS gene circuits as a novel intervention strategy for intestinal diseases. Moreover, the application prospects of QS-based synthetic bacterial therapy were summarized. Finally, the challenges faced by these methods were analyzed to make the targeted recommendations for developing a successful therapeutic strategy for intestinal diseases.
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11
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Fernandes S, Borges A, Gomes IB, Sousa SF, Simões M. Curcumin and 10-undecenoic acid as natural quorum sensing inhibitors of LuxS/AI-2 of Bacillus subtilis and LasI/LasR of Pseudomonas aeruginosa. Food Res Int 2023; 165:112519. [PMID: 36869520 DOI: 10.1016/j.foodres.2023.112519] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 01/06/2023] [Accepted: 01/21/2023] [Indexed: 01/26/2023]
Abstract
The quorum sensing (QS) system is related to cell-to-cell communication as a function of population density, which regulates several physiological functions including biofilm formation and virulence gene expression. QS inhibitors have emerged as a promising strategy to tackle virulence and biofilm development. Among a wide variety of phytochemicals, many of them have been described as QS inhibitors. Driven by their promising clues, this study aimed to identify active phytochemicals against LuxS/autoinducer-2 (AI-2) (as the universal QS system) from Bacillus subtilis and LasI/LasR (as a specific QS system) of Pseudomonas aeruginosa, through in silico analysis followed by in vitro validation. The optimized virtual screening protocols were applied to screen a phytochemical database containing 3479 drug-like compounds. The most promising phytochemicals were curcumin, pioglitazone hydrochloride, and 10-undecenoic acid. In vitro analysis corroborated the QS inhibitory activity of curcumin and 10-undecenoic acid, however, pioglitazone hydrochloride showed no relevant effect. Inhibitory effects on LuxS/AI-2 QS system triggered reduction of 33-77% by curcumin (at 1.25-5 µg/mL) and 36-64% by 10-undecenoic acid (at 12.5-50 µg/mL). Inhibition of LasI/LasR QS system was 21% by curcumin (at 200 µg/mL) and 10-54% by 10-undecenoic acid (at 15.625-250 µg/mL). In conclusion, in silico analysis allowed the identification of curcumin and, for the first time, 10-undecenoic acid (showing low cost, high availability, and low toxicity) as alternatives to counteract bacterial pathogenicity and virulence, avoiding the imposition of selective pressure usually related to classic industrial disinfection and antibiotics therapy.
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Affiliation(s)
- Susana Fernandes
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Anabela Borges
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Inês B Gomes
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Sérgio F Sousa
- UCIBIO/REQUIMTE, BioSIM, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Manuel Simões
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
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12
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Wu X, Fan Y, Wang R, Zhao Q, Ali Q, Wu H, Gu Q, Borriss R, Xie Y, Gao X. Bacillus halotolerans KKD1 induces physiological, metabolic and molecular reprogramming in wheat under saline condition. FRONTIERS IN PLANT SCIENCE 2022; 13:978066. [PMID: 36035675 PMCID: PMC9404337 DOI: 10.3389/fpls.2022.978066] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
Salt stress decreases plant growth and is a major threat to crop yields worldwide. The present study aimed to alleviate salt stress in plants by inoculation with halophilic plant growth-promoting rhizobacteria (PGPR) isolated from an extreme environment in the Qinghai-Tibetan Plateau. Wheat plants inoculated with Bacillus halotolerans KKD1 showed increased seedling morphological parameters and physiological indexes. The expression of wheat genes directly involved in plant growth was upregulated in the presence of KKD1, as shown by real-time quantitative PCR (RT-qPCR) analysis. The metabolism of phytohormones, such as 6-benzylaminopurine and gibberellic acid were also enhanced. Mining of the KKD1 genome corroborated its potential plant growth promotion (PGP) and biocontrol properties. Moreover, KKD1 was able to support plant growth under salt stress by inducing a stress response in wheat by modulating phytohormone levels, regulating lipid peroxidation, accumulating betaine, and excluding Na+. In addition, KKD1 positively affected the soil nitrogen content, soil phosphorus content and soil pH. Our findings indicated that KKD1 is a promising candidate for encouraging wheat plant growth under saline conditions.
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Affiliation(s)
- Xiaohui Wu
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- State Key Laboratory of Plateau Ecology and Agriculture, Department of Grassland Science, College of Agricultural and Husbandry, Qinghai University, Xining, China
| | - Yaning Fan
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Ruoyi Wang
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Qian Zhao
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Qurban Ali
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Huijun Wu
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Qin Gu
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Rainer Borriss
- Institut für Biologie, Humboldt Universität, Berlin, Germany
- Nord Reet UG, Greifswald, Germany
| | - Yongli Xie
- State Key Laboratory of Plateau Ecology and Agriculture, Department of Grassland Science, College of Agricultural and Husbandry, Qinghai University, Xining, China
| | - Xuewen Gao
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
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13
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Abstract
Quorum sensing is described as a widespread cell density-dependent signaling mechanism in bacteria. Groups of cells coordinate gene expression by secreting and responding to diffusible signal molecules. Theory, however, predicts that individual cells may short-circuit this mechanism by directly responding to the signals they produce irrespective of cell density. In this study, we characterize this self-sensing effect in the acyl-homoserine lactone quorum sensing system of Pseudomonas aeruginosa. We show that antiactivators, a set of proteins known to affect signal sensitivity, function to prevent self-sensing. Measuring quorum-sensing gene expression in individual cells at very low densities, we find that successive deletion of antiactivator genes qteE and qslA produces a bimodal response pattern, in which increasing proportions of constitutively induced cells coexist with uninduced cells. Comparing responses of signal-proficient and -deficient cells in cocultures, we find that signal-proficient cells show a much higher response in the antiactivator mutant background but not in the wild-type background. Our results experimentally demonstrate the antiactivator-dependent transition from group- to self-sensing in the quorum-sensing circuitry of P. aeruginosa. Taken together, these findings extend our understanding of the functional capacity of quorum sensing. They highlight the functional significance of antiactivators in the maintenance of group-level signaling and experimentally prove long-standing theoretical predictions.
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14
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Wang L, Chen S, Yu B. Poly-γ-glutamic acid: Recent achievements, diverse applications and future perspectives. Trends Food Sci Technol 2022. [DOI: 10.1016/j.tifs.2021.11.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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15
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Potential spoilage of extended shelf-life (ESL) milk by Bacillus subtilis and Bacillus velezensis. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2021.112487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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16
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Microbial Lipopeptide-Producing Strains and Their Metabolic Roles under Anaerobic Conditions. Microorganisms 2021; 9:microorganisms9102030. [PMID: 34683351 PMCID: PMC8540375 DOI: 10.3390/microorganisms9102030] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/09/2021] [Accepted: 09/10/2021] [Indexed: 01/17/2023] Open
Abstract
The lipopeptide produced by microorganisms is one of the representative biosurfactants and is characterized as a series of structural analogues of different families. Thirty-four families covering about 300 lipopeptide compounds have been reported in the last decades, and most of the reported lipopeptides produced by microorganisms were under aerobic conditions. The lipopeptide-producing strains under anaerobic conditions have attracted much attention from both the academic and industrial communities, due to the needs and the challenge of their applications in anaerobic environments, such as in oil reservoirs and in microbial enhanced oil recovery (MEOR). In this review, the fifty-eight reported bacterial strains, mostly isolated from oil reservoirs and dominated by the species Bacillus subtilis, producing lipopeptide biosurfactants, and the species Pseudomonas aeruginosa, producing glycolipid biosurfactants under anaerobic conditions were summarized. The metabolic pathway and the non-ribosomal peptide synthetases (NRPSs) of the strain Bacillus subtilis under anaerobic conditions were analyzed, which is expected to better understand the key mechanisms of the growth and production of lipopeptide biosurfactants of such kind of bacteria under anaerobic conditions, and to expand the industrial application of anaerobic biosurfactant-producing bacteria.
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Abstract
Foodborne diseases have been witnessing a constant rising trend worldwide, mainly caused by pathogenic microorganisms, such as Bacillus spp., posing a direct threat to public health. The purpose of this study was to evaluate the biological risk of foodborne and probiotic Bacillus spp. in Beijing markets. A total of 55 Bacillus isolates, including 29 B. cereus, 9 B. licheniformis and 7 B. subtilis, mostly found in dairy products (32.7%), were recovered from 106 samples and identified by matrix-assisted laser desorption/ionization mass spectrometry and polymerase chain reaction methods. The susceptibility towards 16 antibiotics was determined using a broth microdilution method. Bacillus showed a high level of resistance to florfenicol (100%), lincomycin (100%), tiamulin (78.2%) and ampicillin (67.3%), while they were all susceptible or intermediate to vancomycin and rifampin. Additionally, we obtained the whole genome of 19 Bacillus strains using high-throughput sequencing, and the rates of resistance genes van, fosB, erm and tet were 57.9%, 57.9%, 21.1% and 26.3%, respectively. Moreover, 100%, 9.1%, 45.5% and 100% of these isolates carried virulence genes nhe, hbl, cytK and entFM, respectively. Lastly, 60% Bacillus strains were positive in hemolysis tests, and 3 B. licheniformis strains displayed an inhibitory activity on the growth of S. aureus ATCC 29213 using agar overlay technique. Our study outlines the characteristics of foodborne Bacillus spp. and provides information for the monitoring of food safety.
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Pasechnek A, Rabinovich L, Stadnyuk O, Azulay G, Mioduser J, Argov T, Borovok I, Sigal N, Herskovits AA. Active Lysogeny in Listeria Monocytogenes Is a Bacteria-Phage Adaptive Response in the Mammalian Environment. Cell Rep 2021; 32:107956. [PMID: 32726621 PMCID: PMC7397523 DOI: 10.1016/j.celrep.2020.107956] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 05/05/2020] [Accepted: 07/02/2020] [Indexed: 01/20/2023] Open
Abstract
Some Listeria monocytogenes (Lm) strains harbor a prophage within the comK gene, which renders it inactive. During Lm infection of macrophage cells, the prophage turns into a molecular switch, promoting comK gene expression and therefore Lm intracellular growth. During this process, the prophage does not produce infective phages or cause bacterial lysis, suggesting it has acquired an adaptive behavior suited to the pathogenic lifestyle of its host. In this study, we demonstrate that this non-classical phage behavior, named active lysogeny, relies on a transcriptional response that is specific to the intracellular niche. While the prophage undergoes lytic induction, the process is arrested midway, preventing the transcription of the late genes. Further, we demonstrate key phage factors, such as LlgA transcription regulator and a DNA replicase, that support the phage adaptive behavior. This study provides molecular insights into the adaptation of phages to their pathogenic hosts, uncovering unusual cooperative interactions.
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Affiliation(s)
- Anna Pasechnek
- The School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel- Aviv 69978, Israel
| | - Lev Rabinovich
- The School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel- Aviv 69978, Israel
| | - Olga Stadnyuk
- The School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel- Aviv 69978, Israel
| | - Gil Azulay
- The School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel- Aviv 69978, Israel
| | - Jessica Mioduser
- The School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel- Aviv 69978, Israel
| | - Tal Argov
- The School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel- Aviv 69978, Israel
| | - Ilya Borovok
- The School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel- Aviv 69978, Israel
| | - Nadejda Sigal
- The School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel- Aviv 69978, Israel
| | - Anat A Herskovits
- The School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel- Aviv 69978, Israel.
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19
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van Gestel J, Bareia T, Tenennbaum B, Dal Co A, Guler P, Aframian N, Puyesky S, Grinberg I, D’Souza GG, Erez Z, Ackermann M, Eldar A. Short-range quorum sensing controls horizontal gene transfer at micron scale in bacterial communities. Nat Commun 2021; 12:2324. [PMID: 33875666 PMCID: PMC8055654 DOI: 10.1038/s41467-021-22649-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 03/17/2021] [Indexed: 02/02/2023] Open
Abstract
In bacterial communities, cells often communicate by the release and detection of small diffusible molecules, a process termed quorum-sensing. Signal molecules are thought to broadly diffuse in space; however, they often regulate traits such as conjugative transfer that strictly depend on the local community composition. This raises the question how nearby cells within the community can be detected. Here, we compare the range of communication of different quorum-sensing systems. While some systems support long-range communication, we show that others support a form of highly localized communication. In these systems, signal molecules propagate no more than a few microns away from signaling cells, due to the irreversible uptake of the signal molecules from the environment. This enables cells to accurately detect micron scale changes in the community composition. Several mobile genetic elements, including conjugative elements and phages, employ short-range communication to assess the fraction of susceptible host cells in their vicinity and adaptively trigger horizontal gene transfer in response. Our results underscore the complex spatial biology of bacteria, which can communicate and interact at widely different spatial scales.
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Affiliation(s)
- Jordi van Gestel
- grid.5801.c0000 0001 2156 2780Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland ,grid.418656.80000 0001 1551 0562Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland ,grid.7400.30000 0004 1937 0650Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland ,grid.419765.80000 0001 2223 3006Swiss Institute of Bioinformatics, Lausanne, Switzerland ,grid.266102.10000 0001 2297 6811Present Address: Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA USA
| | - Tasneem Bareia
- grid.12136.370000 0004 1937 0546The Shmunis School of Biomedicine and Cancer Research, Tel-Aviv University, Tel-Aviv, Israel
| | - Bar Tenennbaum
- grid.12136.370000 0004 1937 0546The Shmunis School of Biomedicine and Cancer Research, Tel-Aviv University, Tel-Aviv, Israel
| | - Alma Dal Co
- grid.5801.c0000 0001 2156 2780Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland ,grid.418656.80000 0001 1551 0562Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland ,grid.38142.3c000000041936754XSchool of Engineering and Applied Sciences, Harvard University, Cambridge, MA USA
| | - Polina Guler
- grid.12136.370000 0004 1937 0546The Shmunis School of Biomedicine and Cancer Research, Tel-Aviv University, Tel-Aviv, Israel
| | - Nitzan Aframian
- grid.12136.370000 0004 1937 0546The Shmunis School of Biomedicine and Cancer Research, Tel-Aviv University, Tel-Aviv, Israel
| | - Shani Puyesky
- grid.12136.370000 0004 1937 0546The Shmunis School of Biomedicine and Cancer Research, Tel-Aviv University, Tel-Aviv, Israel
| | - Ilana Grinberg
- grid.12136.370000 0004 1937 0546The Shmunis School of Biomedicine and Cancer Research, Tel-Aviv University, Tel-Aviv, Israel
| | - Glen G. D’Souza
- grid.5801.c0000 0001 2156 2780Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland ,grid.418656.80000 0001 1551 0562Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland
| | - Zohar Erez
- grid.13992.300000 0004 0604 7563Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Martin Ackermann
- grid.5801.c0000 0001 2156 2780Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland ,grid.418656.80000 0001 1551 0562Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland
| | - Avigdor Eldar
- grid.12136.370000 0004 1937 0546The Shmunis School of Biomedicine and Cancer Research, Tel-Aviv University, Tel-Aviv, Israel
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20
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Sharipova MR, Mardanova AM, Rudakova NL, Pudova DS. Bistability and Formation of the Biofilm Matrix as Adaptive Mechanisms during the Stationary Phase of Bacillus subtilis. Microbiology (Reading) 2021. [DOI: 10.1134/s002626172006017x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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21
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Xu K, Tong Y, Li Y, Tao J, Li J, Zhou J, Liu S. Rational Design of the N-Terminal Coding Sequence for Regulating Enzyme Expression in Bacillus subtilis. ACS Synth Biol 2021; 10:265-276. [PMID: 33464830 DOI: 10.1021/acssynbio.0c00309] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Synonymous mutation of the N-terminal coding sequence (NCS) has been used to regulate gene expression. We here developed a statistical model to predict the effect of the NCSs on protein expression in Bacillus subtilis WB600. First, a synonymous mutation was performed within the first 10 residues of a superfolder green fluorescent protein to generate a library of 172 NCS synonymous mutants with different expression levels. A prediction model was then developed, which adopted G/C frequency at the third position of each codon and minimum free energy of mRNA as the independent variables, using multiple regression analysis between the 11 sequence parameters of the NCS and their fluorescence intensities. By designing the NCS of the 10 signal peptides de novo according to the model, the extracellular yield of B. subtilis pullulanase fused to each signal peptide was up-regulated by up to 515% or down-regulated by at most 79%. This work provided a candidate tool for fine-tuning gene expression or enzyme production in B. subtilis.
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Affiliation(s)
- Kuidong Xu
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China
| | - Yi Tong
- National Engineering Research Center for Corn Deep Processing, Jilin COFCO Biochemical Co. Ltd., Changchun 130033, China
| | - Yi Li
- National Engineering Research Center for Corn Deep Processing, Jilin COFCO Biochemical Co. Ltd., Changchun 130033, China
| | - Jin Tao
- National Engineering Research Center for Corn Deep Processing, Jilin COFCO Biochemical Co. Ltd., Changchun 130033, China
| | - Jianghua Li
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Jingwen Zhou
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China
- Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi 214122, China
| | - Song Liu
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China
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22
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Del Valle I, Fulk EM, Kalvapalle P, Silberg JJ, Masiello CA, Stadler LB. Translating New Synthetic Biology Advances for Biosensing Into the Earth and Environmental Sciences. Front Microbiol 2021; 11:618373. [PMID: 33633695 PMCID: PMC7901896 DOI: 10.3389/fmicb.2020.618373] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/17/2020] [Indexed: 12/26/2022] Open
Abstract
The rapid diversification of synthetic biology tools holds promise in making some classically hard-to-solve environmental problems tractable. Here we review longstanding problems in the Earth and environmental sciences that could be addressed using engineered microbes as micron-scale sensors (biosensors). Biosensors can offer new perspectives on open questions, including understanding microbial behaviors in heterogeneous matrices like soils, sediments, and wastewater systems, tracking cryptic element cycling in the Earth system, and establishing the dynamics of microbe-microbe, microbe-plant, and microbe-material interactions. Before these new tools can reach their potential, however, a suite of biological parts and microbial chassis appropriate for environmental conditions must be developed by the synthetic biology community. This includes diversifying sensing modules to obtain information relevant to environmental questions, creating output signals that allow dynamic reporting from hard-to-image environmental materials, and tuning these sensors so that they reliably function long enough to be useful for environmental studies. Finally, ethical questions related to the use of synthetic biosensors in environmental applications are discussed.
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Affiliation(s)
- Ilenne Del Valle
- Systems, Synthetic, and Physical Biology Graduate Program, Rice University, Houston, TX, United States
| | - Emily M. Fulk
- Systems, Synthetic, and Physical Biology Graduate Program, Rice University, Houston, TX, United States
| | - Prashant Kalvapalle
- Systems, Synthetic, and Physical Biology Graduate Program, Rice University, Houston, TX, United States
| | - Jonathan J. Silberg
- Department of BioSciences, Rice University, Houston, TX, United States
- Department of Bioengineering, Rice University, Houston, TX, United States
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, United States
| | - Caroline A. Masiello
- Department of BioSciences, Rice University, Houston, TX, United States
- Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX, United States
- Department of Chemistry, Rice University, Houston, TX, United States
| | - Lauren B. Stadler
- Department of Civil and Environmental Engineering, Rice University, Houston, TX, United States
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23
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Peptide signaling without feedback in signal production operates as a true quorum sensing communication system in Bacillus subtilis. Commun Biol 2021; 4:58. [PMID: 33420264 PMCID: PMC7794433 DOI: 10.1038/s42003-020-01553-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 12/03/2020] [Indexed: 01/29/2023] Open
Abstract
Bacterial quorum sensing (QS) is based on signal molecules (SM), which increase in concentration with cell density. At critical SM concentration, a variety of adaptive genes sharply change their expression from basic level to maximum level. In general, this sharp transition, a hallmark of true QS, requires an SM dependent positive feedback loop, where SM enhances its own production. Some communication systems, like the peptide SM-based ComQXPA communication system of Bacillus subtilis, do not have this feedback loop and we do not understand how and if the sharp transition in gene expression is achieved. Based on experiments and mathematical modeling, we observed that the SM peptide ComX encodes the information about cell density, specific cell growth rate, and even oxygen concentration, which ensure power-law increase in SM production. This enables together with the cooperative response to SM (ComX) a sharp transition in gene expression level and this without the SM dependent feedback loop. Due to its ultra-sensitive nature, the ComQXPA can operate at SM concentrations that are 100-1000 times lower than typically found in other QS systems, thereby substantially reducing the total metabolic cost of otherwise expensive ComX peptide.
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Crespo I, Bernardo N, Miguel-Arribas A, Singh PK, Luque-Ortega JR, Alfonso C, Malfois M, Meijer WJJ, Boer DR. Inactivation of the dimeric RappLS20 anti-repressor of the conjugation operon is mediated by peptide-induced tetramerization. Nucleic Acids Res 2020; 48:8113-8127. [PMID: 32658272 PMCID: PMC7430634 DOI: 10.1093/nar/gkaa540] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 06/08/2020] [Accepted: 06/15/2020] [Indexed: 12/21/2022] Open
Abstract
Quorum sensing allows bacterial cells to communicate through the release of soluble signaling molecules into the surrounding medium. It plays a pivotal role in controlling bacterial conjugation in Gram-positive cells, a process that has tremendous impact on health. Intracellular regulatory proteins of the RRNPP family are common targets of these signaling molecules. The RRNPP family of gene regulators bind signaling molecules at their C-terminal domain (CTD), but have highly divergent functionalities at their N-terminal effector domains (NTD). This divergence is also reflected in the functional states of the proteins, and is highly interesting from an evolutionary perspective. RappLS20 is an RRNPP encoded on the Bacillus subtilis plasmid pLS20. It relieves the gene repression effectuated by RcopLS20 in the absence of the mature pLS20 signaling peptide Phr*pLS20. We report here an in-depth structural study of apo and Phr*pLS20-bound states of RappLS20 at various levels of atomic detail. We show that apo-RappLS20 is dimeric and that Phr*pLS20-bound Rap forms NTD-mediated tetramers. In addition, we show that RappLS20 binds RcopLS20 directly in the absence of Phr*pLS20 and that addition of Phr*pLS20 releases RcopLS20 from RappLS20. This allows RcopLS20 to bind the promotor region of crucial conjugation genes blocking their expression.
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Affiliation(s)
- Isidro Crespo
- ALBA Synchrotron Light Source, C. de la Llum 2-26, Cerdanyola del Vallès, 08290 Barcelona, Spain
| | - Nerea Bernardo
- ALBA Synchrotron Light Source, C. de la Llum 2-26, Cerdanyola del Vallès, 08290 Barcelona, Spain
| | - Andrés Miguel-Arribas
- Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain
| | - Praveen K Singh
- Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain
| | - Juan R Luque-Ortega
- Molecular Interactions Facility, Centro de Investigaciones Biológicas Margarita Salas (CSIC), C. Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Carlos Alfonso
- Systems Biochemistry of Bacterial Division Lab, Centro de Investigaciones Biológicas Margarita Salas (CSIC), C. Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Marc Malfois
- ALBA Synchrotron Light Source, C. de la Llum 2-26, Cerdanyola del Vallès, 08290 Barcelona, Spain
| | - Wilfried J J Meijer
- Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain
| | - Dirk Roeland Boer
- ALBA Synchrotron Light Source, C. de la Llum 2-26, Cerdanyola del Vallès, 08290 Barcelona, Spain
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25
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Huang R, Zeng J, Zhao D, Yong B, Yu Z. Co-association of Two nir Denitrifiers Under the Influence of Emergent Macrophytes. MICROBIAL ECOLOGY 2020; 80:809-821. [PMID: 32577778 DOI: 10.1007/s00248-020-01545-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 06/15/2020] [Indexed: 06/11/2023]
Abstract
Diverse microorganisms perform similar metabolic process in biogeochemical cycles, whereas they are found of highly genomic differentiation. Biotic interactions should be considered in any community survey of these functional groups, as they contribute to community assembly and ultimately alter ecosystem properties. Current knowledge has mainly been achieved based on functional community characterized by a single gene using co-occurrence network analysis. Biotic interactions between functionally equivalent microorganisms, however, have received much less attention. Herein, we propose the nirK- and nirS-type denitrifier communities represented by these two nitrite reductase (nir)-encoding genes, as model communities to investigate the potential interactions of two nir denitrifiers. We evaluated co-occurrence patterns and co-association network structures of nir denitrifier community from an emergent macrophyte-dominated riparian zone of highly active denitrification in Lake Taihu, China. We found a more segregated pattern in combined nir communities than in individual communities. Network analyses revealed a modularized structure of associating nir denitrifiers. An increased proportion of negative associations among combined communities relative to those of individual communities indicated potential interspecific competition between nirK and nirS denitrifiers. pH and NH4+-N were the most important factors driving co-occurrence and mutual exclusion between nirK and nirS denitrifiers. We also showed the topological importance of nirK denitrifiers acting as module hubs for constructing entire association networks. We revealed previously unexplored co-association relationships between nirK and nirS denitrifiers, which were previously neglected in network analyses of individual communities. Using nir denitrifier community as a model, these findings would be helpful for us to understand the biotic interactions and mechanisms underlying how functional groups co-exist in performing biogeochemical cycles.
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Affiliation(s)
- Rui Huang
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, China
| | - Jin Zeng
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
| | - Dayong Zhao
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, China
| | - Bin Yong
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, China
| | - Zhongbo Yu
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, China
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26
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Xiao Y, Lu Q, Yi X, Zhong G, Liu J. Synergistic Degradation of Pyrethroids by the Quorum Sensing-Regulated Carboxylesterase of Bacillus subtilis BSF01. Front Bioeng Biotechnol 2020; 8:889. [PMID: 32850741 PMCID: PMC7403188 DOI: 10.3389/fbioe.2020.00889] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/10/2020] [Indexed: 12/31/2022] Open
Abstract
The well-studied quorum sensing (QS) mechanism has established a complex knowledge system of how microorganisms behave collectively in natural ecosystems, which contributes to bridging the gap between the ecological functions of microbial communities and the molecular mechanisms of cell-to-cell communication. In particular, the ability of agrochemical degradation has been one most attractive potential of functional bacteria, but the interaction and mutual effects of intracellular degradation and intraspecific behavior remained unclear. In this study, we establish a connection between QS regulation and biodegradation by harnessing the previously isolated Bacillus subtilis BSF01 as a template which degrades various pyrethroids. First, we characterize the genetic and transcriptional basis of comA-involved QS system in B. subtilis BSF01 since the ComQXPA circuit coordinates group behaviors in B. subtilis isolates. Second, the genetic and transcriptional details of pyrethroid-degrading carboxylesterase CesB are defined, and its catalytic capacity is evaluated under different conditions. More importantly, we adopt DNA pull-down and yeast one-hybrid techniques to reveal that the enzymatic degradation of pyrethroids is initiated through QS signal regulator ComA binding to carboxylesterase gene cesB, highlighting the synergistic effect of QS regulation and pyrethroid degradation in B. subtilis BSF01. Taken together, the elucidated mechanism provides novel details on the intercellular response of functional bacteria against xenobiotic exposure, which opens up possibilities to facilitate the in-situ contaminant bioremediation via combining the QS-mediated strategies.
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Affiliation(s)
- Ying Xiao
- Key Laboratory of Integrated Pest Management of Crop in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou, China.,Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China.,Guangdong Research Institute of Petrochemical and Fine Chemical Engineering, Guangzhou, China
| | - Qiqi Lu
- Key Laboratory of Integrated Pest Management of Crop in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou, China.,Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China
| | - Xin Yi
- Key Laboratory of Integrated Pest Management of Crop in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou, China.,Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China
| | - Guohua Zhong
- Key Laboratory of Integrated Pest Management of Crop in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou, China.,Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agricultural Science and Technology, Guangzhou, China
| | - Jie Liu
- Key Laboratory of Integrated Pest Management of Crop in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou, China.,Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China
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27
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Microbial biofilm ecology, in silico study of quorum sensing receptor-ligand interactions and biofilm mediated bioremediation. Arch Microbiol 2020; 203:13-30. [PMID: 32785735 DOI: 10.1007/s00203-020-02012-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 07/17/2020] [Accepted: 08/04/2020] [Indexed: 12/15/2022]
Abstract
Biofilms are structured microbial communities of single or multiple populations in which microbial cells adhere to a surface and get embedded in extracellular polymeric substances (EPS). This review attempts to explain biofilm architecture, development phases, and forces that drive bacteria to promote biofilm mode of growth. Bacterial chemical communication, also known as Quorum sensing (QS), which involves the production, detection, and response to small molecules called autoinducers, is highlighted. The review also provides a brief outline of interspecies and intraspecies cell-cell communication. Additionally, we have performed docking studies using Discovery Studio 4.0, which has enabled our understanding of the prominent interactions between autoinducers and their receptors in different bacterial species while also scoring their interaction energies. Receptors, such as LuxN (Phosphoreceiver domain and RecA domain), LuxP, and LuxR, interacted with their ligands (AI-1, AI-2, and AHL) with a CDocker interaction energy of - 31.6083 kcal/mole; - 34.5821 kcal/mole, - 48.2226 kcal/mole and - 41.5885 kcal/mole, respectively. Since biofilms are ideal for the remediation of contaminants due to their high microbial biomass and their potential to immobilize pollutants, this article also provides an overview of biofilm-mediated bioremediation.
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28
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Sikdar R, Elias M. Quorum quenching enzymes and their effects on virulence, biofilm, and microbiomes: a review of recent advances. Expert Rev Anti Infect Ther 2020; 18:1221-1233. [PMID: 32749905 DOI: 10.1080/14787210.2020.1794815] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Numerous bacterial behaviors are regulated by a cell-density dependent mechanism known as Quorum Sensing (QS). QS relies on communication between bacterial cells using diffusible signaling molecules known as autoinducers. QS regulates physiological processes such as metabolism, virulence, and biofilm formation. Quorum Quenching (QQ) is the inhibition of QS using chemical or enzymatic means to counteract behaviors regulated by QS. AREAS COVERED We examine the main, diverse QS mechanisms present in bacterial species, with a special emphasis on AHL-mediated QS. We also discuss key in vitro and in vivo systems in which interference in QS was investigated. Additionally, we highlight promising developments, such as the substrate preference of the used enzymatic quencher, in the application of interference in QS to counter bacterial virulence. EXPERT OPINION Enabled via the recent isolation of highly stable quorum quenching enzymes and/or molecular engineering efforts, the effects of the interference in QS were recently evaluated outside of the traditional model of single species culture. Signal disruption in complex microbial communities was shown to result in the disruption of complex microbial behaviors, and changes in population structures. These new findings, and future studies, may result in significant changes in the traditional views about QS.
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Affiliation(s)
- Rakesh Sikdar
- Biochemistry, Molecular Biology & Biophysics Department and BioTechnology Institute, University of Minnesota , Saint Paul, Minnesota, USA
| | - Mikael Elias
- Biochemistry, Molecular Biology & Biophysics Department and BioTechnology Institute, University of Minnesota , Saint Paul, Minnesota, USA
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29
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Aframian N, Eldar A. A Bacterial Tower of Babel: Quorum-Sensing Signaling Diversity and Its Evolution. Annu Rev Microbiol 2020; 74:587-606. [PMID: 32680450 DOI: 10.1146/annurev-micro-012220-063740] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Quorum sensing is a process in which bacteria secrete and sense a diffusible molecule, thereby enabling bacterial groups to coordinate their behavior in a density-dependent manner. Quorum sensing has evolved multiple times independently, utilizing different molecular pathways and signaling molecules. A common theme among many quorum-sensing families is their wide range of signaling diversity-different variants within a family code for different signal molecules with a cognate receptor specific to each variant. This pattern of vast allelic polymorphism raises several questions-How do different signaling variants interact with one another? How is this diversity maintained? And how did it come to exist in the first place? Here we argue that social interactions between signaling variants can explain the emergence and persistence of signaling diversity throughout evolution. Finally, we extend the discussion to include cases where multiple diverse systems work in concert in a single bacterium.
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Affiliation(s)
- Nitzan Aframian
- Faculty of Life Sciences, School of Molecular Cell Biology and Biotechnology, Tel-Aviv University, 6997801 Tel-Aviv, Israel; ,
| | - Avigdor Eldar
- Faculty of Life Sciences, School of Molecular Cell Biology and Biotechnology, Tel-Aviv University, 6997801 Tel-Aviv, Israel; ,
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30
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Liu Y, Chen J, Crisante D, Jaramillo Lopez JM, Mahadevan R. Dynamic Cell Programming with Quorum Sensing-Controlled CRISPRi Circuit. ACS Synth Biol 2020; 9:1284-1291. [PMID: 32485106 DOI: 10.1021/acssynbio.0c00148] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Synthetic biology is enabling rapid advances in the areas of biomanufacturing and live therapeutics. Dynamic circuits that can be used to regulate cellular resources and microbial community behavior represent a defining focus of synthetic biology, and have attracted tremendous interest. However, the existing dynamic circuits are mostly gene editing-dependent or cell lysis-based, which limits their broad and convenient application, and in some cases, such lysis-based circuits can suffer from genetic instability due to evolution. There is limited research in quorum sensing-assisted CRISPRi, which can function in a gene editing-independent manner. Here, we constructed a series of quorum sensing controlled CRISPRi systems (Q-CRISPRi), which can dynamically program bacteria by using customized sgRNA without introducing cell lysis. We successfully applied Q-CRISPRi circuits to dynamically program gene expression, population density, phenotype, physical property, and community composition of microbial consortia. The strategies reported here represent methods for dynamic cell programming and could be effective in programming industrially and medically important microorganisms to offer better control of their metabolism and behavior.
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Affiliation(s)
- Yilan Liu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Jinjin Chen
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - David Crisante
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Jhoselyn Marisol Jaramillo Lopez
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
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31
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Babel H, Naranjo-Meneses P, Trauth S, Schulmeister S, Malengo G, Sourjik V, Bischofs IB. Ratiometric population sensing by a pump-probe signaling system in Bacillus subtilis. Nat Commun 2020; 11:1176. [PMID: 32132526 PMCID: PMC7055314 DOI: 10.1038/s41467-020-14840-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 02/04/2020] [Indexed: 12/20/2022] Open
Abstract
Communication by means of diffusible signaling molecules facilitates higher-level organization of cellular populations. Gram-positive bacteria frequently use signaling peptides, which are either detected at the cell surface or ‘probed’ by intracellular receptors after being pumped into the cytoplasm. While the former type is used to monitor cell density, the functions of pump-probe networks are less clear. Here we show that pump-probe networks can, in principle, perform different tasks and mediate quorum-sensing, chronometric and ratiometric control. We characterize the properties of the prototypical PhrA-RapA system in Bacillus subtilis using FRET. We find that changes in extracellular PhrA concentrations are tracked rather poorly; instead, cells accumulate and strongly amplify the signal in a dose-dependent manner. This suggests that the PhrA-RapA system, and others like it, have evolved to sense changes in the composition of heterogeneous populations and infer the fraction of signal-producing cells in a mixed population to coordinate cellular behaviors. Gram-positive bacteria can release signaling peptides that are ‘probed’ by intracellular receptors after being pumped into the cytoplasm. Here, Babel et al. show that these pump-probe networks can infer the fraction of signal-producing cells in a mixed population, and do not necessarily mediate typical quorum-sensing control.
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Affiliation(s)
- Heiko Babel
- BioQuant Center of the University of Heidelberg, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany.,Center for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Pablo Naranjo-Meneses
- BioQuant Center of the University of Heidelberg, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany.,Center for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Stephanie Trauth
- BioQuant Center of the University of Heidelberg, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany.,Center for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Sonja Schulmeister
- BioQuant Center of the University of Heidelberg, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany.,Center for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany
| | - Gabriele Malengo
- Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany.,LOEWE Center for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch Str. 16, 35043, Marburg, Germany
| | - Victor Sourjik
- Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany.,LOEWE Center for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch Str. 16, 35043, Marburg, Germany
| | - Ilka B Bischofs
- BioQuant Center of the University of Heidelberg, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany. .,Center for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany. .,Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany.
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32
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Domenech A, Slager J, Veening JW. Antibiotic-Induced Cell Chaining Triggers Pneumococcal Competence by Reshaping Quorum Sensing to Autocrine-Like Signaling. Cell Rep 2019; 25:2390-2400.e3. [PMID: 30485808 PMCID: PMC6289044 DOI: 10.1016/j.celrep.2018.11.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 09/22/2018] [Accepted: 10/31/2018] [Indexed: 02/06/2023] Open
Abstract
Streptococcus pneumoniae can acquire antibiotic resistance by activation of competence and subsequent DNA uptake. Here, we demonstrate that aztreonam (ATM) and clavulanic acid (CLA) promote competence. We show that both compounds induce cell chain formation by targeting the d,d-carboxypeptidase PBP3. In support of the hypothesis that chain formation promotes competence, we demonstrate that an autolysin mutant (ΔlytB) is hypercompetent. Since competence is initiated by the binding of a small extracellular peptide (CSP) to a membrane-anchored receptor (ComD), we wondered whether chain formation alters CSP diffusion kinetics. Indeed, ATM or CLA presence affects competence synchronization by shifting from global to local quorum sensing, as CSP is primarily retained to chained cells, rather than shared in a common pool. Importantly, autocrine-like signaling prolongs the time window in which the population is able to take up DNA. Together, these insights demonstrate the versatility of quorum sensing and highlight the importance of an accurate antibiotic prescription. Identification of a mechanism by which antibiotics induce competence in S. pneumoniae Antibiotics targeting penicillin-binding protein 3 promote chain formation Cell chains retain, rather than diffuse, the quorum-sensing peptide CSP Chaining populations feature a longer competence and transformation time window
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Affiliation(s)
- Arnau Domenech
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland; Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Jelle Slager
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland; Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands.
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33
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Bridges AA, Bassler BL. The intragenus and interspecies quorum-sensing autoinducers exert distinct control over Vibrio cholerae biofilm formation and dispersal. PLoS Biol 2019; 17:e3000429. [PMID: 31710602 PMCID: PMC6872173 DOI: 10.1371/journal.pbio.3000429] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/21/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022] Open
Abstract
Vibrio cholerae possesses multiple quorum-sensing (QS) systems that control virulence and biofilm formation among other traits. At low cell densities, when QS autoinducers are absent, V. cholerae forms biofilms. At high cell densities, when autoinducers have accumulated, biofilm formation is repressed, and dispersal occurs. Here, we focus on the roles of two well-characterized QS autoinducers that function in parallel. One autoinducer, called cholerae autoinducer-1 (CAI-1), is used to measure Vibrio abundance, and the other autoinducer, called autoinducer-2 (AI-2), is widely produced by different bacterial species and presumed to enable V. cholerae to assess the total bacterial cell density of the vicinal community. The two V. cholerae autoinducers funnel information into a shared signal relay pathway. This feature of the QS system architecture has made it difficult to understand how specific information can be extracted from each autoinducer, how the autoinducers might drive distinct output behaviors, and, in turn, how the bacteria use QS to distinguish kin from nonkin in bacterial communities. We develop a live-cell biofilm formation and dispersal assay that allows examination of the individual and combined roles of the two autoinducers in controlling V. cholerae behavior. We show that the QS system works as a coincidence detector in which both autoinducers must be present simultaneously for repression of biofilm formation to occur. Within that context, the CAI-1 QS pathway is activated when only a few V. cholerae cells are present, whereas the AI-2 pathway is activated only at much higher cell density. The consequence of this asymmetry is that exogenous sources of AI-2, but not CAI-1, contribute to satisfying the coincidence detector to repress biofilm formation and promote dispersal. We propose that V. cholerae uses CAI-1 to verify that some of its kin are present before committing to the high-cell–density QS mode, but it is, in fact, the broadly made autoinducer AI-2 that sets the pace of the V. cholerae QS program. This first report of unique roles for the different V. cholerae autoinducers suggests that detection of kin fosters a distinct outcome from detection of nonkin. The pathogenic bacterium Vibrio cholerae uses both kin and nonkin quorum-sensing autoinducer molecules to control its biofilm life cycle; this study shows that each autoinducer plays a unique role in regulating biofilm formation and dispersal.
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Affiliation(s)
- Andrew A. Bridges
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Bonnie L. Bassler
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
- * E-mail:
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34
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Heterogeneity in Bacterial Specialized Metabolism. J Mol Biol 2019; 431:4589-4598. [DOI: 10.1016/j.jmb.2019.04.042] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 04/24/2019] [Accepted: 04/26/2019] [Indexed: 11/17/2022]
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35
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Liu H, Fan K, Li H, Wang Q, Yang Y, Li K, Xia Y, Xun L. Synthetic Gene Circuits Enable Escherichia coli To Use Endogenous H 2S as a Signaling Molecule for Quorum Sensing. ACS Synth Biol 2019; 8:2113-2120. [PMID: 31386360 DOI: 10.1021/acssynbio.9b00210] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Microorganisms often use specific autoinducers other than common metabolites for quorum sensing (QS). Herein, we demonstrated that Escherichia coli produced sulfide (H2S, HS-, and S2-) with the concentrations proportionally correlated to its cell density. We then designed synthetic gene circuits that used H2S as an autoinducer for quorum sensing. A sulfide/quinone oxidoreductase converted diffusible H2S to indiffusible hydrogen polysulfide (HSnH, n ≥ 2), and a gene regulator CstR sensed the latter to turn on the gene expression. We constructed three element libraries, with which 24 different circuits could be assembled for adjustable sensitivity to cell density. The H2S-mediated gene circuits endowed E. coli cells within the same batch or microcolony with highly synchronous behaviors. Using them we successfully constructed cell factories capable of an autonomous switch from growth phase to production phase. Thus, these circuits provide a new tool-kit for metabolic engineering and synthetic biology.
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Affiliation(s)
- Huaiwei Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, People’s Republic of China
| | - Kaili Fan
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, People’s Republic of China
| | - Huanjie Li
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, People’s Republic of China
| | - Qingda Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, People’s Republic of China
| | - Yunyun Yang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, People’s Republic of China
| | - Kai Li
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, People’s Republic of China
| | - Yongzhen Xia
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, People’s Republic of China
| | - Luying Xun
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, People’s Republic of China
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164-7520, United States
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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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Silva KPT, Boedicker JQ. A neural network model predicts community-level signaling states in a diverse microbial community. PLoS Comput Biol 2019; 15:e1007166. [PMID: 31233492 PMCID: PMC6611639 DOI: 10.1371/journal.pcbi.1007166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 07/05/2019] [Accepted: 06/06/2019] [Indexed: 11/19/2022] Open
Abstract
Signal crosstalk within biological communication networks is common, and such crosstalk can have unexpected consequences for decision making in heterogeneous communities of cells. Here we examined crosstalk within a bacterial community composed of five strains of Bacillus subtilis, with each strain producing a variant of the quorum sensing peptide ComX. In isolation, each strain produced one variant of the ComX signal to induce expression of genes associated with bacterial competence. When strains were combined, a mixture of ComX variants was produced resulting in variable levels of gene expression. To examine gene regulation in mixed communities, we implemented a neural network model. Experimental quantification of asymmetric crosstalk between pairs of strains parametrized the model, enabling the accurate prediction of activity within the full five-strain network. Unlike the single strain system in which quorum sensing activated upon exceeding a threshold concentration of the signal, crosstalk within the five-strain community resulted in multiple community-level quorum sensing states, each with a unique combination of quorum sensing activation among the five strains. Quorum sensing activity of the strains within the community was influenced by the combination and ratio of strains as well as community dynamics. The community-level signaling state was altered through an external signal perturbation, and the output state depended on the timing of the perturbation. Given the ubiquity of signal crosstalk in diverse microbial communities, the application of such neural network models will increase accuracy of predicting activity within microbial consortia and enable new strategies for control and design of bacterial signaling networks.
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Affiliation(s)
- Kalinga Pavan T. Silva
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California, United States of America
| | - James Q. Boedicker
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California, United States of America
- Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
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38
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Bettenworth V, Steinfeld B, Duin H, Petersen K, Streit WR, Bischofs I, Becker A. Phenotypic Heterogeneity in Bacterial Quorum Sensing Systems. J Mol Biol 2019; 431:4530-4546. [PMID: 31051177 DOI: 10.1016/j.jmb.2019.04.036] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 04/19/2019] [Accepted: 04/22/2019] [Indexed: 12/11/2022]
Abstract
Quorum sensing is usually thought of as a collective behavior in which all members of a population partake. However, over the last decade, several reports of phenotypic heterogeneity in quorum sensing-related gene expression have been put forward, thus challenging this view. In the respective systems, cells of isogenic populations did not contribute equally to autoinducer production or target gene activation, and in some cases, the fraction of contributing cells was modulated by environmental factors. Here, we look into potential origins of these incidences and into how initial cell-to-cell variations might be amplified to establish distinct phenotypic heterogeneity. We furthermore discuss potential functions heterogeneity in bacterial quorum sensing systems could serve: as a preparation for environmental fluctuations (bet hedging), as a more cost-effective way of producing public goods (division of labor), as a loophole for genotypic cooperators when faced with non-contributing mutants (cheat protection), or simply as a means to fine-tune the output of the population as a whole (output modulation). We illustrate certain aspects of these recent developments with the model organisms Sinorhizobium meliloti, Sinorhizobium fredii and Bacillus subtilis, which possess quorum sensing systems of different complexity, but all show phenotypic heterogeneity therein.
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Affiliation(s)
- Vera Bettenworth
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, 35043 Marburg, Germany; Faculty of Biology, Philipps-Universität Marburg, 35043 Marburg, Germany.
| | - Benedikt Steinfeld
- BioQuant Center of the University of Heidelberg, 69120 Heidelberg, Germany; Center for Molecular Biology (ZMBH), University of Heidelberg, 69120 Heidelberg, Germany; Max-Planck-Institute for Terrestrial Microbiology, 35043 Marburg, Germany.
| | - Hilke Duin
- Department of Microbiology and Biotechnology, University of Hamburg, 22609 Hamburg, Germany.
| | - Katrin Petersen
- Department of Microbiology and Biotechnology, University of Hamburg, 22609 Hamburg, Germany.
| | - Wolfgang R Streit
- Department of Microbiology and Biotechnology, University of Hamburg, 22609 Hamburg, Germany.
| | - Ilka Bischofs
- BioQuant Center of the University of Heidelberg, 69120 Heidelberg, Germany; Center for Molecular Biology (ZMBH), University of Heidelberg, 69120 Heidelberg, Germany; Max-Planck-Institute for Terrestrial Microbiology, 35043 Marburg, Germany.
| | - Anke Becker
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, 35043 Marburg, Germany; Faculty of Biology, Philipps-Universität Marburg, 35043 Marburg, Germany.
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39
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Abstract
Entry into genetic competence in streptococci is controlled by ComX, an alternative sigma factor for genes that enable the import of exogenous DNA. In Streptococcus mutans, the immediate activator of comX is the ComRS quorum system. ComS is the precursor of XIP, a seven-residue peptide that is imported into the cell and interacts with the cytosolic receptor ComR to form a transcriptional activator for both comX and comS Although intercellular quorum signaling by ComRS has been demonstrated, observations of bimodal expression of comX suggest that comRS may also function as an intracellular feedback loop, activating comX without export or detection of extracellular XIP. Here we used microfluidic and single-cell methods to test whether ComRS induction of comX requires extracellular XIP or ComS. We found that individual comS-overexpressing cells activate their own comX, independently of the rate at which their growth medium is replaced. However, in the absence of lysis they do not activate comS-deficient mutants growing in coculture. We also found that induction of comR and comS genes introduced into Escherichia coli cells leads to activation of a comX reporter. Therefore, ComRS control of comX does not require either the import or extracellular accumulation of ComS or XIP or specific processing of ComS to XIP. We also found that endogenously and exogenously produced ComS and XIP have inequivalent effects on comX activation. These data are fully consistent with identification of intracellular positive feedback in comS transcription as the origin of bimodal comX expression in S. mutans IMPORTANCE The ComRS system can function as a quorum sensing trigger for genetic competence in S. mutans The signal peptide XIP, which is derived from the precursor ComS, enters the cell and interacts with the Rgg-type cytosolic receptor ComR to activate comX, which encodes the alternative sigma factor for the late competence genes. Previous studies have demonstrated intercellular signaling via ComRS, although release of the ComS or XIP peptide to the extracellular medium appears to require lysis of the producing cells. Here we tested the complementary hypothesis that ComRS can drive comX through a purely intracellular mechanism that does not depend on extracellular accumulation or import of ComS or XIP. By combining single-cell, coculture, and microfluidic approaches, we demonstrated that endogenously produced ComS can enable ComRS to activate comX without requiring processing, export, or import. These data provide insight into intracellular mechanisms that generate noise and heterogeneity in S. mutans competence.
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Brown SP, Blackwell HE, Hammer BK. The State of the Union Is Strong: a Review of ASM's 6th Conference on Cell-Cell Communication in Bacteria. J Bacteriol 2018; 200:e00291-18. [PMID: 29760210 PMCID: PMC6018360 DOI: 10.1128/jb.00291-18] [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] [Indexed: 11/20/2022] Open
Abstract
The 6th American Society for Microbiology Conference on Cell-Cell Communication in Bacteria convened from 16 to 19 October 2017 in Athens, GA. In this minireview, we highlight some of the research presented at that meeting that addresses central questions emerging in the field, including the following questions. How are cell-cell communication circuits designed to generate responses? Where are bacteria communicating? Finally, why are bacteria engaging in such behaviors?
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Affiliation(s)
- Sam P Brown
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Brian K Hammer
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
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