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Zanditenas E, Trebicz-Geffen M, Kolli D, Domínguez-García L, Farhi E, Linde L, Romero D, Chapman M, Kolodkin-Gal I, Ankri S. Digestive exophagy of biofilms by intestinal amoeba and its impact on stress tolerance and cytotoxicity. NPJ Biofilms Microbiomes 2023; 9:77. [PMID: 37813896 PMCID: PMC10562373 DOI: 10.1038/s41522-023-00444-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 09/26/2023] [Indexed: 10/11/2023] Open
Abstract
The human protozoan parasite Entamoeba histolytica is responsible for amebiasis, a disease endemic to developing countries. E. histolytica trophozoites colonize the large intestine, primarily feeding on bacteria. However, in the gastrointestinal tract, bacterial cells form aggregates or structured communities called biofilms too large for phagocytosis. Remarkably, trophozoites are still able to invade and degrade established biofilms, utilizing a mechanism that mimics digestive exophagy. Digestive exophagy refers to the secretion of digestive enzymes that promote the digestion of objects too large for direct phagocytosis by phagocytes. E. histolytica cysteine proteinases (CPs) play a crucial role in the degradation process of Bacillus subtilis biofilm. These proteinases target TasA, a major component of the B. subtilis biofilm matrix, also contributing to the adhesion of the parasite to the biofilm. In addition, they are also involved in the degradation of biofilms formed by Gram-negative and Gram-positive enteric pathogens. Furthermore, biofilms also play an important role in protecting trophozoites against oxidative stress. This specific mechanism suggests that the amoeba has adapted to prey on biofilms, potentially serving as an untapped reservoir for novel therapeutic approaches to treat biofilms. Consistently, products derived from the amoeba have been shown to restore antibiotic sensitivity to biofilm cells. In addition, our findings reveal that probiotic biofilms can act as a protective shield for mammalian cells, hindering the progression of the parasite towards them.
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Affiliation(s)
- Eva Zanditenas
- Department of Molecular Microbiology, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Meirav Trebicz-Geffen
- Department of Molecular Microbiology, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Divya Kolli
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, USA
| | - Laura Domínguez-García
- Departamento de Microbiología, Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Málaga, Spain
| | - Einan Farhi
- Technion Genomics Center, Technion - Israel Institute of Technology, Haifa, Israel
| | - Liat Linde
- Technion Genomics Center, Technion - Israel Institute of Technology, Haifa, Israel
| | - Diego Romero
- Departamento de Microbiología, Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Málaga, Spain
| | - Matthew Chapman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, USA
| | - Ilana Kolodkin-Gal
- Department of Plant Pathology and Microbiology, the Robert H. Smith Faculty of Agriculture, Food & Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
- Scojen Institute for Synthetic Biology, Reichman University, Herzliya, Israel.
| | - Serge Ankri
- Department of Molecular Microbiology, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel.
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Cámara-Almirón J, Domínguez-García L, El Mammeri N, Lends A, Habenstein B, de Vicente A, Loquet A, Romero D. Molecular characterization of the N-terminal half of TasA during amyloid-like assembly and its contribution to Bacillus subtilis biofilm formation. NPJ Biofilms Microbiomes 2023; 9:68. [PMID: 37739955 PMCID: PMC10516879 DOI: 10.1038/s41522-023-00437-w] [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: 06/09/2023] [Accepted: 09/12/2023] [Indexed: 09/24/2023] Open
Abstract
Biofilms are bacterial communities that result from a cell differentiation process leading to the secretion of an extracellular matrix (ECM) by part of the population. In Bacillus subtilis, the main protein component of the ECM is TasA, which forms a fiber-based scaffold that confers structure to the ECM. The N-terminal half of TasA is strongly conserved among Bacillus species and contains a protein domain, the rigid core (RcTasA), which is critical for the structural and functional properties of the recombinant protein. In this study, we demonstrate that recombinantly purified RcTasA in vitro retains biochemical properties previously observed for the entire protein. Further analysis of the RcTasA amino acid sequence revealed two aggregation-prone stretches and a region of imperfect amino acid repeats, which are known to contribute to functional amyloid assembly. Biochemical characterization of these stretches found in RcTasA revealed their amyloid-like capacity in vitro, contributing to the amyloid nature of RcTasA. Moreover, the study of the imperfect amino acid repeats revealed the critical role of residues D64, K68 and D69 in the structural function of TasA. Experiments with versions of TasA carrying the substitutions D64A and K68AD69A demonstrated a partial loss of function of the protein either in the assembly of the ECM or in the stability of the core and amyloid-like properties. Taken together, our findings allow us to better understand the polymerization process of TasA during biofilm formation and provide knowledge into the sequence determinants that promote the molecular behavior of protein filaments in bacteria.
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Affiliation(s)
- Jesús Cámara-Almirón
- Departamento de Microbiología, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga, (Campus Universitario de Teatinos), Málaga, Spain
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne, Switzerland
| | - Laura Domínguez-García
- Departamento de Microbiología, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga, (Campus Universitario de Teatinos), Málaga, Spain
| | - Nadia El Mammeri
- CNRS, Chemistry and Biology of Membranes and Nanoobjects (CBMN), Institut Europeen de Chimie et Biologie (IECB), University of Bordeaux, Pessac, France
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA, 02139, USA
| | - Alons Lends
- CNRS, Chemistry and Biology of Membranes and Nanoobjects (CBMN), Institut Europeen de Chimie et Biologie (IECB), University of Bordeaux, Pessac, France
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV, 1006, Latvia
| | - Birgit Habenstein
- CNRS, Chemistry and Biology of Membranes and Nanoobjects (CBMN), Institut Europeen de Chimie et Biologie (IECB), University of Bordeaux, Pessac, France
| | - Antonio de Vicente
- Departamento de Microbiología, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga, (Campus Universitario de Teatinos), Málaga, Spain
| | - Antoine Loquet
- CNRS, Chemistry and Biology of Membranes and Nanoobjects (CBMN), Institut Europeen de Chimie et Biologie (IECB), University of Bordeaux, Pessac, France
| | - Diego Romero
- Departamento de Microbiología, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga, (Campus Universitario de Teatinos), Málaga, Spain.
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3
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Admane N, Kothandan R, Syed S, Biswas S. A quinoline alkaloid potentially modulates the amyloidogenic structural transitions of the biofilm scaffolding small basic protein. J Biomol Struct Dyn 2023; 41:1366-1377. [PMID: 34963419 DOI: 10.1080/07391102.2021.2020165] [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] [Indexed: 01/18/2023]
Abstract
Bacterial biofilm formation by communities of opportunistic bacterial pathogens like Staphylococcus epidermidis is regarded as the primary virulence mechanism facilitating the spread of detrimental nosocomial and implant-associated infections. An 18-kDa small basic protein (Sbp) and its amyloid fibrils account for strengthening the biofilm architecture and scaffolding the S. epidermidis biofilm matrix. Our study reports systematic analysis of the amyloidogenic structural transitions of Sbp and predicts the amyloid core of the protein which may trigger misfolding and aggregation. Herein, we report the novel amyloid inhibitory potential of Camptothecin, a quinoline alkaloid which binds stably to Sbp monomers and redirects the formation of unstructured regions further destabilizing the protein. Molecular dynamics simulations reveal that Camptothecin averts β-sheet transitions, interrupts with electrostatic interactions and disrupts the intermolecular hydrophobic associations between the exposed hydrophobic amyloidogenic regions of Sbp. Collectively, our study puts forward the first report detailing the heteromolecular associations and amyloid modulatory effects of Camptothecin which may serve as a structural scaffold for the tailored designing of novel drugs targeting the S. epidermidis biofilm matrix.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Nikita Admane
- ViStA Lab, Department of Biological Sciences, BITS, Goa, India
| | - Ram Kothandan
- Bioinformatics Laboratory, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, India
| | - Sowfia Syed
- Bioinformatics Laboratory, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, India
| | - Sumit Biswas
- ViStA Lab, Department of Biological Sciences, BITS, Goa, India
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4
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Böhning J, Ghrayeb M, Pedebos C, Abbas DK, Khalid S, Chai L, Bharat TAM. Donor-strand exchange drives assembly of the TasA scaffold in Bacillus subtilis biofilms. Nat Commun 2022; 13:7082. [PMID: 36400765 PMCID: PMC9674648 DOI: 10.1038/s41467-022-34700-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 11/03/2022] [Indexed: 11/19/2022] Open
Abstract
Many bacteria in nature exist in multicellular communities termed biofilms, where cells are embedded in an extracellular matrix that provides rigidity to the biofilm and protects cells from chemical and mechanical stresses. In the Gram-positive model bacterium Bacillus subtilis, TasA is the major protein component of the biofilm matrix, where it has been reported to form functional amyloid fibres contributing to biofilm structure and stability. Here, we present electron cryomicroscopy structures of TasA fibres, which show that, rather than forming amyloid fibrils, TasA monomers assemble into fibres through donor-strand exchange, with each subunit donating a β-strand to complete the fold of the next subunit along the fibre. Combining electron cryotomography, atomic force microscopy, and mutational studies, we show how TasA fibres congregate in three dimensions to form abundant fibre bundles that are essential for B. subtilis biofilm formation. Our study explains the previously observed biochemical properties of TasA and shows how a bacterial extracellular globular protein can assemble from monomers into β-sheet-rich fibres, and how such fibres assemble into bundles in biofilms.
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Affiliation(s)
- Jan Böhning
- grid.4991.50000 0004 1936 8948Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE UK
| | - Mnar Ghrayeb
- grid.9619.70000 0004 1937 0538Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 91904 Israel ,grid.9619.70000 0004 1937 0538The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 91904 Israel
| | - Conrado Pedebos
- grid.4991.50000 0004 1936 8948Department of Biochemistry, University of Oxford, Oxford, OX1 3QU UK
| | - Daniel K. Abbas
- grid.4991.50000 0004 1936 8948Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE UK
| | - Syma Khalid
- grid.4991.50000 0004 1936 8948Department of Biochemistry, University of Oxford, Oxford, OX1 3QU UK
| | - Liraz Chai
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 91904, Israel. .,The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 91904, Israel.
| | - Tanmay A. M. Bharat
- grid.4991.50000 0004 1936 8948Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE UK ,grid.42475.300000 0004 0605 769XStructural Studies Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH UK
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5
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Abstract
Complex interactions between microbial populations can greatly affect the overall properties of a microbial community, sometimes leading to cooperation and mutually beneficial coexistence, or competition and the death or displacement of organisms or subpopulations. Interactions between different biofilm populations are highly relevant in diverse scientific areas, from antimicrobial resistance to microbial ecology. The utilization of modern microscopic techniques has provided a new and interesting insight into how bacteria interact at the cellular level to form and maintain microbial biofilms. However, our ability to follow complex intraspecies and interspecies interactions in vivo at the microscopic level has remained somewhat limited. Here, we detailed BacLive, a novel noninvasive method for tracking bacterial growth and biofilm dynamics using high-resolution fluorescence microscopy and an associated ImageJ processing macro (https://github.com/BacLive) for easier data handling and image analysis. Finally, we provided examples of how BacLive can be used in the analysis of complex bacterial communities. IMPORTANCE Communication and interactions between single cells are continuously defining the structure and composition of microbial communities temporally and spatially. Methods routinely used to study these communities at the cellular level rely on sample manipulation which makes microscopic time-lapse experiments impossible. BacLive was conceived as a method for the noninvasive study of the formation and development of bacterial communities, such as biofilms, and the formation dynamics of specialized subpopulations in time-lapse experiments at a colony level. In addition, we developed a tool to simplify the processing and analysis of the data generated by this method.
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6
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Akbey Ü, Andreasen M. Functional amyloids from bacterial biofilms - structural properties and interaction partners. Chem Sci 2022; 13:6457-6477. [PMID: 35756505 PMCID: PMC9172111 DOI: 10.1039/d2sc00645f] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/05/2022] [Indexed: 12/26/2022] Open
Abstract
Protein aggregation and amyloid formation have historically been linked with various diseases such as Alzheimer's and Parkinson's disease, but recently functional amyloids have gained a great deal of interest in not causing a disease and having a distinct function in vivo. Functional bacterial amyloids form the structural scaffold in bacterial biofilms and provide a survival strategy for the bacteria along with antibiotic resistance. The formation of functional amyloids happens extracellularly which differs from most disease related amyloids. Studies of functional amyloids have revealed several distinctions compared to disease related amyloids including primary structures designed to optimize amyloid formation while still retaining a controlled assembly of the individual subunits into classical cross-β-sheet structures, along with a unique cross-α-sheet amyloid fold. Studies have revealed that functional amyloids interact with components found in the extracellular matrix space such as lipids from membranes and polymers from the biofilm. Intriguingly, a level of complexity is added as functional amyloids also interact with several disease related amyloids and a causative link has even been established between functional amyloids and neurodegenerative diseases. It is hence becoming increasingly clear that functional amyloids are not inert protein structures found in bacterial biofilms but interact with many different components including human proteins related to pathology. Gaining a clear understanding of the factors governing the interactions will lead to improved strategies to combat biofilm associated infections and the correlated antibiotic resistance. In the current review we summarize the current state of the art knowledge on this exciting and fast growing research field of biofilm forming bacterial functional amyloids, their structural features and interaction partners.
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Affiliation(s)
- Ümit Akbey
- Department of Structural Biology, School of Medicine, University of Pittsburgh Pittsburgh PA 15261 USA
| | - Maria Andreasen
- Department of Biomedicine, Aarhus University Wilhelm Meyers Allé 3 8000 Aarhus Denmark
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7
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Cohen-Cymberknoh M, Kolodkin-Gal D, Keren-Paz A, Peretz S, Brumfeld V, Kapishnikov S, Suissa R, Shteinberg M, McLeod D, Maan H, Patrauchan M, Zamir G, Kerem E, Kolodkin-Gal I. Calcium carbonate mineralization is essential for biofilm formation and lung colonization. iScience 2022; 25:104234. [PMID: 35521519 PMCID: PMC9062676 DOI: 10.1016/j.isci.2022.104234] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 08/18/2021] [Accepted: 04/07/2022] [Indexed: 11/27/2022] Open
Abstract
Biofilms are differentiated microbial communities held together by an extracellular matrix. μCT X-ray revealed structured mineralized areas within biofilms of lung pathogens belonging to two distant phyla - the proteobacteria Pseudomonas aeruginosa and the actinobacteria Mycobacterium abscessus. Furthermore, calcium chelation inhibited the assembly of complex bacterial structures for both organisms with little to no effect on cell growth. The molecular mechanisms promoting calcite scaffold formation were surprisingly conserved between the two pathogens as biofilm development was similarly impaired by genetic and biochemical inhibition of calcium uptake and carbonate accumulation. Moreover, chemical inhibition and mutations targeting mineralization significantly reduced the attachment of P. aeruginosa to the lung, as well as the subsequent damage inflicted by biofilms to lung tissues, and restored their sensitivity to antibiotics. This work offers underexplored druggable targets for antibiotics to combat otherwise untreatable biofilm infections.
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Affiliation(s)
- Malena Cohen-Cymberknoh
- Pediatric Pulmonary Unit and Cystic fibrosis Center, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Israel
| | - Dror Kolodkin-Gal
- Department of Experimental Surgery, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Alona Keren-Paz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
- National Center for Antibiotic Resistance and Infection Control, Tel Aviv Medical Center, Tel Aviv, Israel
| | - Shani Peretz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Vlad Brumfeld
- Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
| | - Sergey Kapishnikov
- Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
| | - Ronit Suissa
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Michal Shteinberg
- Pulmonology Institute and CF Center, Carmel Medical Center, Haifa, Israel
| | - Daniel McLeod
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Harsh Maan
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Marianna Patrauchan
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Gideon Zamir
- Department of Experimental Surgery, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Eitan Kerem
- Pediatric Pulmonary Unit and Cystic fibrosis Center, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Israel
| | - Ilana Kolodkin-Gal
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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8
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Fessia A, Barra P, Barros G, Nesci A. Could Bacillus biofilms enhance the effectivity of biocontrol strategies in the phyllosphere? J Appl Microbiol 2022; 133:2148-2166. [PMID: 35476896 DOI: 10.1111/jam.15596] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/13/2022] [Accepted: 04/21/2022] [Indexed: 11/30/2022]
Abstract
Maize (Zea mays L.), a major crop in Argentina and a staple food around the world, is affected by the emergence and re-emergence of foliar diseases. Agrochemicals are the main control strategy nowadays, but they can cause resistance in insects and microbial pathogens and have negative effects on the environment and human health. An emerging alternative is the use of living organisms, i.e. microbial biocontrol agents, to suppress plant pathogen populations. This is a risk-free approach when the organisms acting as biocontrol agents come from the same ecosystem as the foliar pathogens they are meant to antagonize. Some epiphytic microorganisms may form biofilm by becoming aggregated and attached to a surface, as is the case of spore-forming bacteria from the genus Bacillus. Their ability to sporulate and their tolerance to long storage periods make them a frequently used biocontrol agent. Moreover, the biofilm that they create protects them against different abiotic and biotic factors and helps them to acquire nutrients, which ensures their survival on the plants they protect. This review analyzes the interactions that the phyllosphere-inhabiting Bacillus genus establishes with its environment through biofilm, and how this lifestyle could serve to design effective biological control strategies.
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Affiliation(s)
- Aluminé Fessia
- Laboratorio de Ecología Microbiana, Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ruta Nacional 36, Km 601, X5804ZAB Río Cuarto, Córdoba, Argentina
| | - Paula Barra
- Laboratorio de Ecología Microbiana, Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ruta Nacional 36, Km 601, X5804ZAB Río Cuarto, Córdoba, Argentina
| | - Germán Barros
- Laboratorio de Ecología Microbiana, Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ruta Nacional 36, Km 601, X5804ZAB Río Cuarto, Córdoba, Argentina
| | - Andrea Nesci
- Laboratorio de Ecología Microbiana, Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ruta Nacional 36, Km 601, X5804ZAB Río Cuarto, Córdoba, Argentina
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9
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Lin Y, Briandet R, Kovács ÁT. Bacillus cereus sensu lato biofilm formation and its ecological importance. Biofilm 2022; 4:100070. [PMID: 35243332 PMCID: PMC8861577 DOI: 10.1016/j.bioflm.2022.100070] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 02/04/2022] [Accepted: 02/05/2022] [Indexed: 12/20/2022] Open
Abstract
Biofilm formation is a ubiquitous process of bacterial communities that enables them to survive and persist in various environmental niches. The Bacillus cereus group includes phenotypically diversified species that are widely distributed in the environment. Often, B. cereus is considered a soil inhabitant, but it is also commonly isolated from plant roots, nematodes, and food products. Biofilms differ in their architecture and developmental processes, reflecting adaptations to specific niches. Importantly, some B. cereus strains are foodborne pathogens responsible for two types of gastrointestinal diseases, diarrhea and emesis, caused by distinct toxins. Thus, the persistency of biofilms is of particular concern for the food industry, and understanding the underlying mechanisms of biofilm formation contributes to cleaning procedures. This review focuses on the genetic background underpinning the regulation of biofilm development, as well as the matrix components associated with biofilms. We also reflect on the correlation between biofilm formation and the development of highly resistant spores. Finally, advances in our understanding of the ecological importance and evolution of biofilm formation in the B. cereus group are discussed.
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10
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Multiscale X-ray study of Bacillus subtilis biofilms reveals interlinked structural hierarchy and elemental heterogeneity. Proc Natl Acad Sci U S A 2022; 119:2118107119. [PMID: 35042817 PMCID: PMC8794879 DOI: 10.1073/pnas.2118107119] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2021] [Indexed: 11/24/2022] Open
Abstract
Biofilms are multicellular, soft microbial communities that are able to colonize synthetic surfaces as well as living organisms. To survive sudden environmental changes and efficiently share their common resources, cells in a biofilm divide into subgroups with distinct functions, leading to phenotypic heterogeneity. Here, by studying intact biofilms by synchrotron X-ray diffraction and fluorescence, we revealed correlations between biofilm macroscopic, architectural heterogeneity and the spatiotemporal distribution of extracellular matrix, spores, water, and metal ions. Our findings demonstrate that biofilm heterogeneity is not only affected by local genetic expression and cellular differentiation but also by passive effects resulting from the physicochemical properties of the molecules secreted by the cells, leading to differential distribution of nutrients that propagate through macroscopic length scales. Biofilms are multicellular microbial communities that encase themselves in an extracellular matrix (ECM) of secreted biopolymers and attach to surfaces and interfaces. Bacterial biofilms are detrimental in hospital and industrial settings, but they can be beneficial, for example, in agricultural as well as in food technology contexts. An essential property of biofilms that grants them with increased survival relative to planktonic cells is phenotypic heterogeneity, the division of the biofilm population into functionally distinct subgroups of cells. Phenotypic heterogeneity in biofilms can be traced to the cellular level; however, the molecular structures and elemental distribution across whole biofilms, as well as possible linkages between them, remain unexplored. Mapping X-ray diffraction across intact biofilms in time and space, we revealed the dominant structural features in Bacillus subtilis biofilms, stemming from matrix components, spores, and water. By simultaneously following the X-ray fluorescence signal of biofilms and isolated matrix components, we discovered that the ECM preferentially binds calcium ions over other metal ions, specifically, zinc, manganese, and iron. These ions, remaining free to flow below macroscopic wrinkles that act as water channels, eventually accumulate and may possibly lead to sporulation. The possible link between ECM properties, regulation of metal ion distribution, and sporulation across whole, intact biofilms unravels the importance of molecular-level heterogeneity in shaping biofilm physiology and development.
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11
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Sanchez-Vizuete P, Dergham Y, Bridier A, Deschamps J, Dervyn E, Hamze K, Aymerich S, Le Coq D, Briandet R. The coordinated population redistribution between Bacillus subtilis submerged biofilm and liquid-air pellicle. Biofilm 2022; 4:100065. [PMID: 35024609 PMCID: PMC8732777 DOI: 10.1016/j.bioflm.2021.100065] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/09/2021] [Accepted: 12/14/2021] [Indexed: 12/15/2022] Open
Abstract
Bacillus subtilis is a widely used bacterial model to decipher biofilm formation, genetic determinants and their regulation. For several years, studies were conducted on colonies or pellicles formed at the interface with air, but more recent works showed that non-domesticated strains were able to form thick and structured biofilms on submerged surfaces. Taking advantage of time-lapse confocal laser scanning microscopy, we monitored bacterial colonization on the surface and observed an unexpected biphasic submerged biofilm development. Cells adhering to the surface firstly form elongated chains before being suddenly fragmented and released as free motile cells in the medium. This switching coincided with an oxygen depletion in the well which preceded the formation of the pellicle at the liquid-air interface. Residual bacteria still associated with the solid surface at the bottom of the well started to express matrix genes under anaerobic metabolism to build the typical biofilm protruding structures.
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Affiliation(s)
- Pilar Sanchez-Vizuete
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Yasmine Dergham
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France.,Faculty of Science, Lebanese University, 1003, Beirut, Lebanon
| | - Arnaud Bridier
- Fougères Laboratory, Antibiotics, Biocides, Residues and Resistance Unit, Anses, 35300, Fougères, France
| | - Julien Deschamps
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Etienne Dervyn
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Kassem Hamze
- Faculty of Science, Lebanese University, 1003, Beirut, Lebanon
| | - Stéphane Aymerich
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Dominique Le Coq
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France.,Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS), INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Romain Briandet
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
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12
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Ghassemi N, Poulhazan A, Deligey F, Mentink-Vigier F, Marcotte I, Wang T. Solid-State NMR Investigations of Extracellular Matrixes and Cell Walls of Algae, Bacteria, Fungi, and Plants. Chem Rev 2021; 122:10036-10086. [PMID: 34878762 DOI: 10.1021/acs.chemrev.1c00669] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Extracellular matrixes (ECMs), such as the cell walls and biofilms, are important for supporting cell integrity and function and regulating intercellular communication. These biomaterials are also of significant interest to the production of biofuels and the development of antimicrobial treatment. Solid-state nuclear magnetic resonance (ssNMR) and magic-angle spinning-dynamic nuclear polarization (MAS-DNP) are uniquely powerful for understanding the conformational structure, dynamical characteristics, and supramolecular assemblies of carbohydrates and other biomolecules in ECMs. This review highlights the recent high-resolution investigations of intact ECMs and native cells in many organisms spanning across plants, bacteria, fungi, and algae. We spotlight the structural principles identified in ECMs, discuss the current technical limitation and underexplored biochemical topics, and point out the promising opportunities enabled by the recent advances of the rapidly evolving ssNMR technology.
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Affiliation(s)
- Nader Ghassemi
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Alexandre Poulhazan
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.,Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Fabien Deligey
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | | | - Isabelle Marcotte
- Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Tuo Wang
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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13
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Zaidi-Ait Salem M, Nait Chabane Y, Girbal-Neuhauser E. Architecture and physico-chemical properties of Bacillus amyloliquefaciens L-17 pellicle formed at the air-liquid interface. J Biosci Bioeng 2021; 132:560-568. [PMID: 34538716 DOI: 10.1016/j.jbiosc.2021.07.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/20/2021] [Accepted: 07/29/2021] [Indexed: 11/28/2022]
Abstract
Bacillus amyloliquefaciens is a ubiquitous soil and plant-associated bacterial species which shows structural and adaptative responses to the environment. This present paper explores the ability of the strain L-17 to form subaerial biofilms on a liquid surface. Hydrophobic and non-wetting properties were observed for the rough top biofilm layer in contact with the air, which are quite different to the hydrophilic properties which were observed for the smooth biofilm layer in contact with the liquid. Both pellicle interfaces were visualized by scanning electron microscopy revealing a complex three-dimensional architecture composed of exopolymers organized in stacked fibrous network or sheet-like structures in the vicinity of the subaerial surface. Disruption of the extracellular matrix by combining physical and chemical treatments indicated that both loosely and tightly bound polysaccharides were found as major components of this complex pellicle. Proteins were also involved in the aggregation and cohesion of the matrix as multi extraction steps were needed to recover some tightly bounded proteins. This was confirmed by applying protease treatment which was able to significantly disrupt the pellicle. Overall results underline the ability of B. amyloliquefaciens L-17 to survive on air-liquid interfaces. This feature offers an interesting strategy to escape aquatic environments and develop aerial biofilm in response to environmental changes involving wet-dry cycles.
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Affiliation(s)
- Meriem Zaidi-Ait Salem
- Laboratoire de Biotechnologies Agroalimentaire et Environnementale (LBAE), URU 4565, UPS, Université de Toulouse, IUT Paul Sabatier, 24 rue d'Embaquès, F-32000 Auch, France
| | - Yassine Nait Chabane
- Laboratoire de Biotechnologies Agroalimentaire et Environnementale (LBAE), URU 4565, UPS, Université de Toulouse, IUT Paul Sabatier, 24 rue d'Embaquès, F-32000 Auch, France
| | - Elisabeth Girbal-Neuhauser
- Laboratoire de Biotechnologies Agroalimentaire et Environnementale (LBAE), URU 4565, UPS, Université de Toulouse, IUT Paul Sabatier, 24 rue d'Embaquès, F-32000 Auch, France.
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14
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Arnaouteli S, Bamford NC, Stanley-Wall NR, Kovács ÁT. Bacillus subtilis biofilm formation and social interactions. Nat Rev Microbiol 2021; 19:600-614. [PMID: 33824496 DOI: 10.1038/s41579-021-00540-9] [Citation(s) in RCA: 155] [Impact Index Per Article: 51.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2021] [Indexed: 02/03/2023]
Abstract
Biofilm formation is a process in which microbial cells aggregate to form collectives that are embedded in a self-produced extracellular matrix. Bacillus subtilis is a Gram-positive bacterium that is used to dissect the mechanisms controlling matrix production and the subsequent transition from a motile planktonic cell state to a sessile biofilm state. The collective nature of life in a biofilm allows emergent properties to manifest, and B. subtilis biofilms are linked with novel industrial uses as well as probiotic and biocontrol processes. In this Review, we outline the molecular details of the biofilm matrix and the regulatory pathways and external factors that control its production. We explore the beneficial outcomes associated with biofilms. Finally, we highlight major advances in our understanding of concepts of microbial evolution and community behaviour that have resulted from studies of the innate heterogeneity of biofilms.
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Affiliation(s)
- Sofia Arnaouteli
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Natalie C Bamford
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Nicola R Stanley-Wall
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK.
| | - Ákos T Kovács
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark.
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15
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Gallup O, Ming H, Ellis T. Ten future challenges for synthetic biology. ENGINEERING BIOLOGY 2021; 5:51-59. [PMID: 36968258 PMCID: PMC9996719 DOI: 10.1049/enb2.12011] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 12/15/2022] Open
Abstract
After 2 decades of growth and success, synthetic biology has now become a mature field that is driving significant innovation in the bioeconomy and pushing the boundaries of the biomedical sciences and biotechnology. So what comes next? In this article, 10 technological advances are discussed that are expected and hoped to come from the next generation of research and investment in synthetic biology; from ambitious projects to make synthetic life, cell simulators and custom genomes, through to new methods of engineering biology that use automation, deep learning and control of evolution. The non-exhaustive list is meant to inspire those joining the field and looks forward to how synthetic biology may evolve over the coming decades.
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Affiliation(s)
- Olivia Gallup
- Department of Bioengineering Imperial College London London UK
| | - Hia Ming
- Department of Bioengineering Imperial College London London UK
| | - Tom Ellis
- Department of Bioengineering Imperial College London London UK
- Imperial College Centre for Synthetic Biology Imperial College London London UK
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16
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Daskalov A, El Mammeri N, Lends A, Shenoy J, Lamon G, Fichou Y, Saad A, Martinez D, Morvan E, Berbon M, Grélard A, Kauffmann B, Ferber M, Bardiaux B, Habenstein B, Saupe SJ, Loquet A. Structures of Pathological and Functional Amyloids and Prions, a Solid-State NMR Perspective. Front Mol Neurosci 2021; 14:670513. [PMID: 34276304 PMCID: PMC8280340 DOI: 10.3389/fnmol.2021.670513] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 05/26/2021] [Indexed: 12/20/2022] Open
Abstract
Infectious proteins or prions are a remarkable class of pathogens, where pathogenicity and infectious state correspond to conformational transition of a protein fold. The conformational change translates into the formation by the protein of insoluble amyloid aggregates, associated in humans with various neurodegenerative disorders and systemic protein-deposition diseases. The prion principle, however, is not limited to pathogenicity. While pathological amyloids (and prions) emerge from protein misfolding, a class of functional amyloids has been defined, consisting of amyloid-forming domains under natural selection and with diverse biological roles. Although of great importance, prion amyloid structures remain challenging for conventional structural biology techniques. Solid-state nuclear magnetic resonance (SSNMR) has been preferentially used to investigate these insoluble, morphologically heterogeneous aggregates with poor crystallinity. SSNMR methods have yielded a wealth of knowledge regarding the fundamentals of prion biology and have helped to solve the structures of several prion and prion-like fibrils. Here, we will review pathological and functional amyloid structures and will discuss some of the obtained structural models. We will finish the review with a perspective on integrative approaches combining solid-state NMR, electron paramagnetic resonance and cryo-electron microscopy, which can complement and extend our toolkit to structurally explore various facets of prion biology.
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Affiliation(s)
- Asen Daskalov
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Nadia El Mammeri
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Alons Lends
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | | | - Gaelle Lamon
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Yann Fichou
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Ahmad Saad
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Denis Martinez
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Estelle Morvan
- CNRS, INSERM, IECB, UMS 3033, University of Bordeaux, Pessac, France
| | - Melanie Berbon
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Axelle Grélard
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Brice Kauffmann
- CNRS, INSERM, IECB, UMS 3033, University of Bordeaux, Pessac, France
| | | | | | | | - Sven J. Saupe
- CNRS, IBGC UMR 5095, University of Bordeaux, Bordeaux, France
| | - Antoine Loquet
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
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17
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Molina-Santiago C, de Vicente A, Romero D. Bacterial extracellular matrix as a natural source of biotechnologically multivalent materials. Comput Struct Biotechnol J 2021; 19:2796-2805. [PMID: 34093994 PMCID: PMC8138678 DOI: 10.1016/j.csbj.2021.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/29/2021] [Accepted: 05/02/2021] [Indexed: 12/15/2022] Open
Abstract
The extracellular matrix (ECM) is an intricate megastructure made by bacterial cells to form architecturally complex biostructures called biofilms. Protection of cells, modulation of cell-to-cell signalling, cell differentiation and environmental sensing are functions of the ECM that reflect its diverse chemical composition. Proteins, polysaccharides and eDNA have specific functionalities while cooperatively interacting to sustain the architecture and biological relevance of the ECM. The accumulated evidence on the chemical heterogeneity and specific functionalities of ECM components has attracted attention because of their potential biotechnological applications, from agriculture to the water and food industries. This review compiles information on the most relevant bacterial ECM components, the biophysical and chemical features responsible for their biological roles, and their potential to be further translated into biotechnological applications.
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Affiliation(s)
- Carlos Molina-Santiago
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Universidad de Málaga, Bulevar Louis Pasteur 31 (Campus Universitario de teatinos), 29071 Málaga, Spain
| | - Antonio de Vicente
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Universidad de Málaga, Bulevar Louis Pasteur 31 (Campus Universitario de teatinos), 29071 Málaga, Spain
| | - Diego Romero
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Universidad de Málaga, Bulevar Louis Pasteur 31 (Campus Universitario de teatinos), 29071 Málaga, Spain
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18
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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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19
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Fibrilar Polymorphism of the Bacterial Extracellular Matrix Protein TasA. Microorganisms 2021; 9:microorganisms9030529. [PMID: 33806534 PMCID: PMC8000256 DOI: 10.3390/microorganisms9030529] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 02/23/2021] [Accepted: 03/01/2021] [Indexed: 12/25/2022] Open
Abstract
Functional amyloid proteins often appear as fibers in extracellular matrices of microbial soft colonies. In contrast to disease-related amyloid structures, they serve a functional goal that benefits the organism that secretes them, which is the reason for the title “functional”. Biofilms are a specific example of a microbial community in which functional amyloid fibers play a role. Functional amyloid proteins contribute to the mechanical stability of biofilms and mediate the adhesion of the cells to themselves as well as to surfaces. Recently, it has been shown that functional amyloid proteins also play a regulatory role in biofilm development. TasA is the major proteinaceous fibrilar component of the extracellular matrix of biofilms made of the soil bacterium and Gram-positive Bacillus subtilis. We have previously shown, as later corroborated by others, that in acidic solutions, TasA forms compact aggregates that are composed of tangled fibers. Here, we show that in a neutral pH and above a certain TasA concentration, the fibers of TasA are elongated and straight and that they bundle up in highly concentrated salt solutions. TasA fibers resemble the canonic amyloid morphology; however, these fibers also bear an interesting nm-scale periodicity along the fiber axis. At the molecular level, TasA fibers contain a twisted β-sheet structure, as indicated by circular dichroism measurements. Our study shows that the morphology of TasA fibers depends on the environmental conditions. Different fibrilar morphologies may be related with different functional roles in biofilms, ranging from granting biofilms with a mechanical support to acting as antibiotic agents.
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20
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Multifunctional Amyloids in the Biology of Gram-Positive Bacteria. Microorganisms 2020; 8:microorganisms8122020. [PMID: 33348645 PMCID: PMC7766987 DOI: 10.3390/microorganisms8122020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/11/2020] [Accepted: 12/14/2020] [Indexed: 01/18/2023] Open
Abstract
Since they were discovered, amyloids have proven to be versatile proteins able to participate in a variety of cellular functions across all kingdoms of life. This multitask trait seems to reside in their ability to coexist as monomers, aggregates or fibrillar entities, with morphological and biochemical peculiarities. It is precisely this common molecular behaviour that allows amyloids to cross react with one another, triggering heterologous aggregation. In bacteria, many of these functional amyloids are devoted to the assembly of biofilms by organizing the matrix scaffold that keeps cells together. However, consistent with their notion of multifunctional proteins, functional amyloids participate in other biological roles within the same organisms, and emerging unprecedented functions are being discovered. In this review, we focus on functional amyloids reported in gram-positive bacteria, which are diverse in their assembly mechanisms and remarkably specific in their biological functions that they perform. Finally, we consider cross-seeding between functional amyloids as an emerging theme in interspecies interactions that contributes to the diversification of bacterial biology.
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21
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Emerging Roles of Functional Bacterial Amyloids in Gene Regulation, Toxicity, and Immunomodulation. Microbiol Mol Biol Rev 2020; 85:85/1/e00062-20. [PMID: 33239434 DOI: 10.1128/mmbr.00062-20] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacteria often reside in multicellular communities, called biofilms, held together by an extracellular matrix. In many bacteria, the major proteinaceous component of the biofilm are amyloid fibers. Amyloids are highly stable and structured protein aggregates which were known mostly to be associated with neurodegenerative diseases, such as Alzheimer's, Parkinson's, and Huntington's diseases. In recent years, microbial amyloids were identified also in other species and shown to play major roles in microbial physiology and virulence. For example, amyloid fibers assemble on the bacterial cell surface as a part of the extracellular matrix and are extremely important to the scaffolding and structural integrity of biofilms, which contribute to microbial resilience and resistance. Furthermore, microbial amyloids play fundamental nonscaffold roles that contribute to the development of biofilms underlying numerous persistent infections. Here, we review several nonscaffold roles of bacterial amyloid proteins, including bridging cells during collective migration, acting as regulators of cell fate, as toxins against other bacteria or against host immune cells, and as modulators of the hosts' immune system. These overall points on the complexity of the amyloid fold in encoding numerous activities, which offer approaches for the development of a novel repertoire of antivirulence therapeutics.
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22
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Lee M, Ghosh U, Thurber KR, Kato M, Tycko R. Molecular structure and interactions within amyloid-like fibrils formed by a low-complexity protein sequence from FUS. Nat Commun 2020; 11:5735. [PMID: 33184287 PMCID: PMC7665218 DOI: 10.1038/s41467-020-19512-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 10/14/2020] [Indexed: 12/13/2022] Open
Abstract
Protein domains without the usual distribution of amino acids, called low complexity (LC) domains, can be prone to self-assembly into amyloid-like fibrils. Self-assembly of LC domains that are nearly devoid of hydrophobic residues, such as the 214-residue LC domain of the RNA-binding protein FUS, is particularly intriguing from the biophysical perspective and is biomedically relevant due to its occurrence within neurons in amyotrophic lateral sclerosis, frontotemporal dementia, and other neurodegenerative diseases. We report a high-resolution molecular structural model for fibrils formed by the C-terminal half of the FUS LC domain (FUS-LC-C, residues 111-214), based on a density map with 2.62 Å resolution from cryo-electron microscopy (cryo-EM). In the FUS-LC-C fibril core, residues 112-150 adopt U-shaped conformations and form two subunits with in-register, parallel cross-β structures, arranged with quasi-21 symmetry. All-atom molecular dynamics simulations indicate that the FUS-LC-C fibril core is stabilized by a plethora of hydrogen bonds involving sidechains of Gln, Asn, Ser, and Tyr residues, both along and transverse to the fibril growth direction, including diverse sidechain-to-backbone, sidechain-to-sidechain, and sidechain-to-water interactions. Nuclear magnetic resonance measurements additionally show that portions of disordered residues 151-214 remain highly dynamic in FUS-LC-C fibrils and that fibrils formed by the N-terminal half of the FUS LC domain (FUS-LC-N, residues 2-108) have the same core structure as fibrils formed by the full-length LC domain. These results contribute to our understanding of the molecular structural basis for amyloid formation by FUS and by LC domains in general.
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Affiliation(s)
- Myungwoon Lee
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, 20892-0520, USA
| | - Ujjayini Ghosh
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, 20892-0520, USA
| | - Kent R Thurber
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, 20892-0520, USA
| | - Masato Kato
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas, 75390-9152, USA
- Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, 20892-0520, USA.
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23
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Levkovich SA, Gazit E, Laor Bar-Yosef D. Two Decades of Studying Functional Amyloids in Microorganisms. Trends Microbiol 2020; 29:251-265. [PMID: 33041179 DOI: 10.1016/j.tim.2020.09.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/19/2020] [Accepted: 09/07/2020] [Indexed: 12/22/2022]
Abstract
In the past two decades, amyloids, typically associated with human diseases, have been described to play various functional roles in nearly all life forms. The structural and functional diversity of microbial 'functional amyloids' has dramatically increased in recent years, expanding the canonical definition of these assembled molecules. Here, we provide a broad review of the current understanding of microbial functional amyloids and their diverse roles, putting the spotlight on recent discoveries in the field. We discuss their functions as structural scaffolds, surface-tension modulators, adhesion molecules, cell-cycle and gametogenesis regulators, toxins, and mediators of host-pathogen interactions. We outline how noncanonical amyloid morphologies and sophisticated regulatory mechanisms underlie their functional diversity and emphasize their therapeutic and biotechnological implications and applications.
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Affiliation(s)
- Shon A Levkovich
- School of Molecular Cell Biology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ehud Gazit
- School of Molecular Cell Biology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel; BLAVATNIK CENTER for Drug Discovery, Tel Aviv University, Tel Aviv 69978, Israel; Department of Materials Science and Engineering, Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel; Sagol Interdisciplinary School of Neurosciences, Tel Aviv University, Tel Aviv, Israel.
| | - Dana Laor Bar-Yosef
- School of Molecular Cell Biology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
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24
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Kosolapova AO, Antonets KS, Belousov MV, Nizhnikov AA. Biological Functions of Prokaryotic Amyloids in Interspecies Interactions: Facts and Assumptions. Int J Mol Sci 2020; 21:E7240. [PMID: 33008049 PMCID: PMC7582709 DOI: 10.3390/ijms21197240] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 02/07/2023] Open
Abstract
Amyloids are fibrillar protein aggregates with an ordered spatial structure called "cross-β". While some amyloids are associated with development of approximately 50 incurable diseases of humans and animals, the others perform various crucial physiological functions. The greatest diversity of amyloids functions is identified within prokaryotic species where they, being the components of the biofilm matrix, function as adhesins, regulate the activity of toxins and virulence factors, and compose extracellular protein layers. Amyloid state is widely used by different pathogenic bacterial species in their interactions with eukaryotic organisms. These amyloids, being functional for bacteria that produce them, are associated with various bacterial infections in humans and animals. Thus, the repertoire of the disease-associated amyloids includes not only dozens of pathological amyloids of mammalian origin but also numerous microbial amyloids. Although the ability of symbiotic microorganisms to produce amyloids has recently been demonstrated, functional roles of prokaryotic amyloids in host-symbiont interactions as well as in the interspecies interactions within the prokaryotic communities remain poorly studied. Here, we summarize the current findings in the field of prokaryotic amyloids, classify different interspecies interactions where these amyloids are involved, and hypothesize about their real occurrence in nature as well as their roles in pathogenesis and symbiosis.
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Affiliation(s)
- Anastasiia O. Kosolapova
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia (K.S.A.); (M.V.B.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| | - Kirill S. Antonets
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia (K.S.A.); (M.V.B.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| | - Mikhail V. Belousov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia (K.S.A.); (M.V.B.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| | - Anton A. Nizhnikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia (K.S.A.); (M.V.B.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
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25
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Ido N, Lybman A, Hayet S, Azulay DN, Ghrayeb M, Liddawieh S, Chai L. Bacillus subtilis biofilms characterized as hydrogels. Insights on water uptake and water binding in biofilms. SOFT MATTER 2020; 16:6180-6190. [PMID: 32567645 DOI: 10.1039/d0sm00581a] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Biofilms are aggregates of cells that form on surfaces or at the air-water interface. Cells in a biofilm are encased in a self-secreted extracellular matrix (ECM) that provides them with mechanical stability and protects them from antibiotic treatment. From a soft matter perspective, biofilms are regarded as colloidal hydrogels, with the cells playing the role of colloids and the ECM compared with a cross-linked hydrogel. Here, we examined whole biofilms of the soil bacterium Bacillus subtilis utilizing methods that are commonly used to characterize hydrogels in order to evaluate the uptake of water and the water properties in the biofilms. Specifically, we studied wild-type as well ECM mutants, lacking the protein TasA and the exopolysaccharide (EPS). We characterized the morphology and mesh size of biofilms using electron microscopy, studied the state of water in the biofilms using differential scanning calorimetry, and finally, we tested the biofilms' swelling properties. Our study revealed that Bacillus subtilis biofilms resemble cross-linked hydrogels in their morphology and swelling properties. Strikingly, we discovered that all the water in biofilms was bound water and there was no free water in the biofilms. Water binding was mostly related with the presence of solutes and much less so with the major ECM components, the protein TasA and the polysaccharide EPS. This study sheds light on water uptake and water binding in biofilms and it is therefore important for the understanding of solute transport and enzymatic function inside biofilms.
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Affiliation(s)
- Nir Ido
- The Israel Institute for Biological Research, Ness Ziona, Israel
| | - Amir Lybman
- The Israel Institute for Biological Research, Ness Ziona, Israel
| | - Shahar Hayet
- Institute of Chemistry, The Hebrew University of Jerusalem and The Center for Nanoscience and Nanotechnology, Edmond J. Safra Campus, Jerusalem 91904, Israel.
| | - David N Azulay
- Institute of Chemistry, The Hebrew University of Jerusalem and The Center for Nanoscience and Nanotechnology, Edmond J. Safra Campus, Jerusalem 91904, Israel.
| | - Mnar Ghrayeb
- Institute of Chemistry, The Hebrew University of Jerusalem and The Center for Nanoscience and Nanotechnology, Edmond J. Safra Campus, Jerusalem 91904, Israel.
| | - Sajeda Liddawieh
- Institute of Chemistry, The Hebrew University of Jerusalem and The Center for Nanoscience and Nanotechnology, Edmond J. Safra Campus, Jerusalem 91904, Israel.
| | - Liraz Chai
- Institute of Chemistry, The Hebrew University of Jerusalem and The Center for Nanoscience and Nanotechnology, Edmond J. Safra Campus, Jerusalem 91904, Israel.
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Abstract
Amyloids are protein polymers that were initially linked to human diseases. Across the whole Tree of Life, many disease-unrelated proteins are now emerging for which amyloids represent distinct functional states. Most bacterial amyloids described are extracellular, contributing to biofilm formation. However, only a few have been found in the bacterial cytosol. This paper reviews from the perspective of synthetic biology (SynBio) our understanding of the subtle line that separates functional from pathogenic and transmissible amyloids (prions). Amyloids are protein polymers that were initially linked to human diseases. Across the whole Tree of Life, many disease-unrelated proteins are now emerging for which amyloids represent distinct functional states. Most bacterial amyloids described are extracellular, contributing to biofilm formation. However, only a few have been found in the bacterial cytosol. This paper reviews from the perspective of synthetic biology (SynBio) our understanding of the subtle line that separates functional from pathogenic and transmissible amyloids (prions). In particular, it is focused on RepA-WH1, a functional albeit unconventional natural amyloidogenic protein domain that participates in controlling DNA replication of bacterial plasmids. SynBio approaches, including protein engineering and the design of allosteric effectors such as diverse ligands and an optogenetic module, have enabled the generation in RepA-WH1 of an intracellular cytotoxic prion-like agent in bacteria. The synthetic RepA-WH1 prion has the potential to develop into novel antimicrobials.
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Earl C, Arnaouteli S, Bamford NC, Porter M, Sukhodub T, MacPhee CE, Stanley-Wall NR. The majority of the matrix protein TapA is dispensable for Bacillus subtilis colony biofilm architecture. Mol Microbiol 2020; 114:920-933. [PMID: 32491277 DOI: 10.1111/mmi.14559] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 01/08/2023]
Abstract
Biofilm formation is a co-operative behaviour, where microbial cells become embedded in an extracellular matrix. This biomolecular matrix helps manifest the beneficial or detrimental outcome mediated by the collective of cells. Bacillus subtilis is an important bacterium for understanding the principles of biofilm formation. The protein components of the B. subtilis matrix include the secreted proteins BslA, which forms a hydrophobic coat over the biofilm, and TasA, which forms protease-resistant fibres needed for structuring. TapA is a secreted protein also needed for biofilm formation and helps in vivo TasA-fibre formation but is dispensable for in vitro TasA-fibre assembly. We show that TapA is subjected to proteolytic cleavage in the colony biofilm and that only the first 57 amino acids of the 253-amino acid protein are required for colony biofilm architecture. Through the construction of a strain which lacks all eight extracellular proteases, we show that proteolytic cleavage by these enzymes is not a prerequisite for TapA function. It remains unknown why TapA is synthesised at 253 amino acids when the first 57 are sufficient for colony biofilm structuring; the findings do not exclude the core conserved region of TapA having a second role beyond structuring the B. subtilis colony biofilm.
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Affiliation(s)
- Chris Earl
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Sofia Arnaouteli
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Natalie C Bamford
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Michael Porter
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Tetyana Sukhodub
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Cait E MacPhee
- James Clerk Maxwell Building, School of Physics, University of Edinburgh, Edinburgh, UK
| | - Nicola R Stanley-Wall
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
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28
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Tu Z, R. Abhyankar W, N. Swarge B, van der Wel N, Kramer G, Brul S, J. de Koning L. Artificial Sporulation Induction (ASI) by kinA Overexpression Affects the Proteomes and Properties of Bacillus subtilis Spores. Int J Mol Sci 2020; 21:ijms21124315. [PMID: 32560401 PMCID: PMC7352945 DOI: 10.3390/ijms21124315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/07/2020] [Accepted: 06/16/2020] [Indexed: 12/15/2022] Open
Abstract
To facilitate more accurate spore proteomic analysis, the current study focuses on inducing homogeneous sporulation by overexpressing kinA and assesses the effect of synchronized sporulation initiation on spore resistance, structures, the germination behavior at single-spore level and the proteome. The results indicate that, in our set up, the sporulation by overexpressing kinA can generate a spore yield of 70% within 8 h. The procedure increases spore wet heat resistance and thickness of the spore coat and cortex layers, whilst delaying the time to spore phase-darkening and burst after addition of germinant. The proteome analysis reveals that the upregulated proteins in the kinA induced spores, compared to spores without kinA induction, as well as the 'wildtype' spores, are mostly involved in spore formation. The downregulated proteins mostly belong to the categories of coping with stress, carbon and nitrogen metabolism, as well as the regulation of sporulation. Thus, while kinA overexpression enhances synchronicity in sporulation initiation, it also has profound effects on the central equilibrium of spore formation and spore germination, through modulation of the spore molecular composition and stress resistance physiology.
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Affiliation(s)
- Zhiwei Tu
- Laboratory for Molecular Biology and Microbial Food Safety, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands; (Z.T.); (W.R.A.); (B.N.S.)
- Laboratory for Mass Spectrometry of Biomolecules, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands; (G.K.); (L.J.d.K.)
| | - Wishwas R. Abhyankar
- Laboratory for Molecular Biology and Microbial Food Safety, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands; (Z.T.); (W.R.A.); (B.N.S.)
- Laboratory for Mass Spectrometry of Biomolecules, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands; (G.K.); (L.J.d.K.)
| | - Bhagyashree N. Swarge
- Laboratory for Molecular Biology and Microbial Food Safety, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands; (Z.T.); (W.R.A.); (B.N.S.)
- Laboratory for Mass Spectrometry of Biomolecules, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands; (G.K.); (L.J.d.K.)
| | - Nicole van der Wel
- Department of Medical Biology, Electron Microscopy Centre Amsterdam, Amsterdam University Medical Centers, University of Amsterdam, 1100 DD Amsterdam, The Netherlands;
| | - Gertjan Kramer
- Laboratory for Mass Spectrometry of Biomolecules, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands; (G.K.); (L.J.d.K.)
| | - Stanley Brul
- Laboratory for Molecular Biology and Microbial Food Safety, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands; (Z.T.); (W.R.A.); (B.N.S.)
- Correspondence: ; Tel.: +31-20-525-7079 (ext. 6970)
| | - Leo J. de Koning
- Laboratory for Mass Spectrometry of Biomolecules, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands; (G.K.); (L.J.d.K.)
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29
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Steinberg N, Keren-Paz A, Hou Q, Doron S, Yanuka-Golub K, Olender T, Hadar R, Rosenberg G, Jain R, Cámara-Almirón J, Romero D, van Teeffelen S, Kolodkin-Gal I. The extracellular matrix protein TasA is a developmental cue that maintains a motile subpopulation within Bacillus subtilis biofilms. Sci Signal 2020; 13:13/632/eaaw8905. [PMID: 32430292 DOI: 10.1126/scisignal.aaw8905] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In nature, bacteria form biofilms-differentiated multicellular communities attached to surfaces. Within these generally sessile biofilms, a subset of cells continues to express motility genes. We found that this subpopulation enabled Bacillus subtilis biofilms to expand on high-friction surfaces. The extracellular matrix (ECM) protein TasA was required for the expression of flagellar genes. In addition to its structural role as an adhesive fiber for cell attachment, TasA acted as a developmental signal stimulating a subset of biofilm cells to revert to a motile phenotype. Transcriptomic analysis revealed that TasA stimulated the expression of a specific subset of genes whose products promote motility and repress ECM production. Spontaneous suppressor mutations that restored motility in the absence of TasA revealed that activation of the biofilm-motility switch by the two-component system CssR/CssS antagonized the TasA-mediated reversion to motility in biofilm cells. Our results suggest that although mostly sessile, biofilms retain a degree of motility by actively maintaining a motile subpopulation.
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Affiliation(s)
- Nitai Steinberg
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.,Department of Microbiology, Institute Pasteur, Paris, France
| | - Alona Keren-Paz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Qihui Hou
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Shany Doron
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Keren Yanuka-Golub
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Tsviya Olender
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Rotem Hadar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Gili Rosenberg
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Rakeshkumar Jain
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Jesus Cámara-Almirón
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Departamento de Microbiología, Universidad de Málaga, Málaga, Spain
| | - Diego Romero
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Departamento de Microbiología, Universidad de Málaga, Málaga, Spain
| | | | - Ilana Kolodkin-Gal
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
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30
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Dual functionality of the amyloid protein TasA in Bacillus physiology and fitness on the phylloplane. Nat Commun 2020; 11:1859. [PMID: 32313019 PMCID: PMC7171179 DOI: 10.1038/s41467-020-15758-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 03/27/2020] [Indexed: 02/07/2023] Open
Abstract
Bacteria can form biofilms that consist of multicellular communities embedded in an extracellular matrix (ECM). In Bacillus subtilis, the main protein component of the ECM is the functional amyloid TasA. Here, we study further the roles played by TasA in B. subtilis physiology and biofilm formation on plant leaves and in vitro. We show that ΔtasA cells exhibit a range of cytological symptoms indicative of excessive cellular stress leading to increased cell death. TasA associates to the detergent-resistant fraction of the cell membrane, and the distribution of the flotillin-like protein FloT is altered in ΔtasA cells. We propose that, in addition to a structural function during ECM assembly and interactions with plants, TasA contributes to the stabilization of membrane dynamics as cells enter stationary phase. The amyloid protein TasA is a main component of the extracellular matrix in Bacillus subtilis biofilms. Here the authors show that, in addition to a structural function during biofilm assembly and interactions with plants, TasA contributes to the stabilization of membrane dynamics during stationary phase.
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