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Kabanov D, Khabipova N, Valeeva L, Sharipova M, Rogov A, Kuznetsova S, Abaseva I, Mardanova A. Effect of Subtilisin-like Proteinase of Bacillus pumilus 3–19 on Pseudomonas aeruginosa Biofilms. BIONANOSCIENCE 2019. [DOI: 10.1007/s12668-019-00617-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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52
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Gilbert C, Ellis T. Biological Engineered Living Materials: Growing Functional Materials with Genetically Programmable Properties. ACS Synth Biol 2019; 8:1-15. [PMID: 30576101 DOI: 10.1021/acssynbio.8b00423] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Natural biological materials exhibit remarkable properties: self-assembly from simple raw materials, precise control of morphology, diverse physical and chemical properties, self-repair, and the ability to sense-and-respond to environmental stimuli. Despite having found numerous uses in human industry and society, the utility of natural biological materials is limited. But, could it be possible to genetically program microbes to create entirely new and useful biological materials? At the intersection between microbiology, material science, and synthetic biology, the emerging field of biological engineered living materials (ELMs) aims to answer this question. Here we review recent efforts to program cells to produce living materials with novel functional properties, focusing on microbial systems that can be engineered to grow materials and on new genetic circuits for pattern formation that could be used to produce the more complex systems of the future.
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Affiliation(s)
- Charlie Gilbert
- Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, U.K
- Department of Bioengineering, Imperial College London, London SW7 2AZ, U.K
| | - Tom Ellis
- Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, U.K
- Department of Bioengineering, Imperial College London, London SW7 2AZ, U.K
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53
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Abstract
To interact with the external environments, bacteria often display long proteinaceous appendages on their cell surface, called pili or fimbriae. These non-flagellar thread-like structures are polymers composed of covalently or non-covalently interacting repeated pilin subunits. Distinct pilus classes can be identified on basis of their assembly pathways, including chaperone-usher pili, type V pili, type IV pili, curli and fap fibers, conjugative and type IV secretion pili, as well as sortase-mediated pili. Pili play versatile roles in bacterial physiology, and can be involved in adhesion and host cell invasion, DNA and protein secretion and uptake, biofilm formation, cell motility and more. Recent advances in structure determination of components involved in the various pilus systems has enabled a better molecular understanding of their mechanisms of assembly and function. In this chapter we describe the diversity in structure, biogenesis and function of the different pilus systems found in Gram-positive and Gram-negative bacteria, and review their potential as anti-microbial targets.
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Affiliation(s)
- Magdalena Lukaszczyk
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050, Brussels, Belgium
| | - Brajabandhu Pradhan
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050, Brussels, Belgium
| | - Han Remaut
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050, Brussels, Belgium.
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54
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Bacterial Amyloids: Biogenesis and Biomaterials. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1174:113-159. [DOI: 10.1007/978-981-13-9791-2_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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55
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Christensen LFB, Hansen LM, Finster K, Christiansen G, Nielsen PH, Otzen DE, Dueholm MS. The Sheaths of Methanospirillum Are Made of a New Type of Amyloid Protein. Front Microbiol 2018; 9:2729. [PMID: 30483237 PMCID: PMC6242892 DOI: 10.3389/fmicb.2018.02729] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/25/2018] [Indexed: 12/12/2022] Open
Abstract
The genera Methanospirillum and Methanosaeta contain species of anaerobic archaea that grow and divide within proteinaceous tubular sheaths that protect them from environmental stressors. The sheaths of Methanosaeta thermophila PT are composed of the 60.9 kDa major sheath protein MspA. In this study we show that sheaths purified from Methanospirillum hungatei JF-1 are regularly striated tubular structures with amyloid-like properties similar to those of M. thermophila PT. Depolymerizing the sheaths from M. hungatei JF-1 allowed us to identify a 40.6 kDa protein (WP_011449234.1) that shares 23% sequence similarity to MspA from M. thermophila PT (ABK14853.1), indicating that they might be distant homologs. The genome of M. hungatei JF-1 encodes six homologs of the identified MspA protein. Several homologs also exist in the related strains Methanospirillum stamsii Pt1 (7 homologs, 28–66% sequence identity), M. lacunae Ki8-1 C (15 homologs, 29–60% sequence identity) and Methanolinea tarda NOBI-1 (2 homologs, 31% sequence identity). The MspA protein discovered here could accordingly represent a more widely found sheath protein than the MspA from M. thermophila PT, which currently has no homologs in the NCBI Reference Sequence database (RefSeq).
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Affiliation(s)
- Line Friis Bakmann Christensen
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Lonnie Maria Hansen
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Kai Finster
- Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Gunna Christiansen
- Section for Medical Microbiology and Immunology, Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Per Halkjær Nielsen
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Daniel Erik Otzen
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Morten Simonsen Dueholm
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
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56
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Rouse SL, Matthews SJ, Dueholm MS. Ecology and Biogenesis of Functional Amyloids in Pseudomonas. J Mol Biol 2018; 430:3685-3695. [PMID: 29753779 PMCID: PMC6173800 DOI: 10.1016/j.jmb.2018.05.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 05/03/2018] [Accepted: 05/04/2018] [Indexed: 12/02/2022]
Abstract
Functional amyloids can be found in the extracellular matrix produced by many bacteria during biofilm growth. They mediate the initial attachment of bacteria to surfaces and provide stability and functionality to mature biofilms. Efficient amyloid biogenesis requires a highly coordinated system of amyloid subunits, molecular chaperones and transport systems. The functional amyloid of Pseudomonas (Fap) represents such a system. Here, we review the phylogenetic diversification of the Fap system, its potential ecological role and the dedicated machinery required for Fap biogenesis, with a particular focus on the amyloid exporter FapF, the structure of which has been recently resolved. We also present a sequence covariance-based in silico model of the FapC fiber-forming subunit. Finally, we highlight key questions that remain unanswered and we believe deserve further attention by the scientific community.
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Affiliation(s)
- Sarah L Rouse
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Stephen J Matthews
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Morten S Dueholm
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark.
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57
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Bhasne K, Mukhopadhyay S. Formation of Heterotypic Amyloids: α-Synuclein in Co-Aggregation. Proteomics 2018; 18:e1800059. [PMID: 30216674 DOI: 10.1002/pmic.201800059] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/28/2018] [Indexed: 12/13/2022]
Abstract
Protein misfolding resulting in the formation of ordered amyloid aggregates is associated with a number of devastating human diseases. Intrinsically disordered proteins (IDPs) do not autonomously fold up into a unique stable conformation and remain as an ensemble of rapidly fluctuating conformers. Many IDPs are prone to convert into the β-rich amyloid state. One such amyloidogenic IDP is α-synuclein that is involved in Parkinson's disease. Recent studies have indicated that other neuronal proteins, especially IDPs, can co-aggregate with α-synuclein in many pathological ailments. This article describes several such observations highlighting the role of heterotypic protein-protein interactions in the formation of hetero-amyloids. It is believed that the characterizations of molecular cross talks between amyloidogenic proteins as well as the mechanistic studies of heterotypic protein aggregation will allow us to decipher the role of the interacting proteins in amyloid proteomics.
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Affiliation(s)
- Karishma Bhasne
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab 140306, India.,Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab 140306, India
| | - Samrat Mukhopadhyay
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab 140306, India.,Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab 140306, India
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58
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Curli-Containing Enteric Biofilms Inside and Out: Matrix Composition, Immune Recognition, and Disease Implications. Microbiol Mol Biol Rev 2018; 82:82/4/e00028-18. [PMID: 30305312 DOI: 10.1128/mmbr.00028-18] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Biofilms of enteric bacteria are highly complex, with multiple components that interact to fortify the biofilm matrix. Within biofilms of enteric bacteria such as Escherichia coli and Salmonella species, the main component of the biofilm is amyloid curli. Other constituents include cellulose, extracellular DNA, O antigen, and various surface proteins, including BapA. Only recently, the roles of these components in the formation of the enteric biofilm individually and in consortium have been evaluated. In addition to enhancing the stability and strength of the matrix, the components of the enteric biofilm influence bacterial virulence and transmission. Most notably, certain components of the matrix are recognized as pathogen-associated molecular patterns. Systemic recognition of enteric biofilms leads to the activation of several proinflammatory innate immune receptors, including the Toll-like receptor 2 (TLR2)/TLR1/CD14 heterocomplex, TLR9, and NLRP3. In the model of Salmonella enterica serovar Typhimurium, the immune response to curli is site specific. Although a proinflammatory response is generated upon systemic presentation of curli, oral administration of curli ameliorates the damaged intestinal epithelial barrier and reduces the severity of colitis. Furthermore, curli (and extracellular DNA) of enteric biofilms potentiate the autoimmune disease systemic lupus erythematosus (SLE) and promote the fibrillization of the pathogenic amyloid α-synuclein, which is implicated in Parkinson's disease. Homologues of curli-encoding genes are found in four additional bacterial phyla, suggesting that the biomedical implications involved with enteric biofilms are applicable to numerous bacterial species.
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59
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Van Gerven N, Van der Verren SE, Reiter DM, Remaut H. The Role of Functional Amyloids in Bacterial Virulence. J Mol Biol 2018; 430:3657-3684. [PMID: 30009771 PMCID: PMC6173799 DOI: 10.1016/j.jmb.2018.07.010] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/05/2018] [Accepted: 07/06/2018] [Indexed: 12/14/2022]
Abstract
Amyloid fibrils are best known as a product of human and animal protein misfolding disorders, where amyloid formation is associated with cytotoxicity and disease. It is now evident that for some proteins, the amyloid state constitutes the native structure and serves a functional role. These functional amyloids are proving widespread in bacteria and fungi, fulfilling diverse functions as structural components in biofilms or spore coats, as toxins and surface-active fibers, as epigenetic material, peptide reservoirs or adhesins mediating binding to and internalization into host cells. In this review, we will focus on the role of functional amyloids in bacterial pathogenesis. The role of functional amyloids as virulence factor is diverse but mostly indirect. Nevertheless, functional amyloid pathways deserve consideration for the acute and long-term effects of the infectious disease process and may form valid antimicrobial targets. Functional amyloids are widespread in bacteria, pathogenic and non-pathogenic. Bacterial biofilms most commonly function as structural support in the extracellular matrix of biofilms or spore coats, and in cell–cell and cell-surface adherence. The amyloid state can be the sole structured and functional state, or can be facultative, as a secondary state to folded monomeric subunits. Bacterial amyloids can enhance virulence by increasing persistence, cell adherence and invasion, intracellular survival, and pathogen spread by increased environmental survival. Bacterial amyloids may indirectly inflict disease by triggering inflammation, contact phase activation and possibly induce or aggravate human pathological aggregation disorders.
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Affiliation(s)
- Nani Van Gerven
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Sander E Van der Verren
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Dirk M Reiter
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Han Remaut
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050 Brussels, Belgium.
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60
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Nguyen PQ, Courchesne NMD, Duraj-Thatte A, Praveschotinunt P, Joshi NS. Engineered Living Materials: Prospects and Challenges for Using Biological Systems to Direct the Assembly of Smart Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1704847. [PMID: 29430725 PMCID: PMC6309613 DOI: 10.1002/adma.201704847] [Citation(s) in RCA: 201] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/25/2017] [Indexed: 05/20/2023]
Abstract
Vast potential exists for the development of novel, engineered platforms that manipulate biology for the production of programmed advanced materials. Such systems would possess the autonomous, adaptive, and self-healing characteristics of living organisms, but would be engineered with the goal of assembling bulk materials with designer physicochemical or mechanical properties, across multiple length scales. Early efforts toward such engineered living materials (ELMs) are reviewed here, with an emphasis on engineered bacterial systems, living composite materials which integrate inorganic components, successful examples of large-scale implementation, and production methods. In addition, a conceptual exploration of the fundamental criteria of ELM technology and its future challenges is presented. Cradled within the rich intersection of synthetic biology and self-assembling materials, the development of ELM technologies allows the power of biology to be leveraged to grow complex structures and objects using a palette of bio-nanomaterials.
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Affiliation(s)
- Peter Q. Nguyen
- School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
| | - Noémie-Manuelle Dorval Courchesne
- School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
| | - Anna Duraj-Thatte
- School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
| | - Pichet Praveschotinunt
- School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
| | - Neel S. Joshi
- School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
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61
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Abstract
Many bacteria can assemble functional amyloid fibers on their cell surface. Most bacterial amyloids contribute to biofilm or other community behaviors where cells interact with a surface or with other cells. Bacterial amyloids, like all functional amyloids, share structural and biochemical properties with disease-associated eukaryotic amyloids. The general ability of amyloids to bind specific dyes, like Congo red and Thioflavin T, and their resistance to denaturation have provided useful tools for scoring and quantifying bacterial amyloid formation. Here, we present basic approaches to study bacterial amyloids by focusing on the well-studied curli amyloid fibers expressed by Enterobacteriaceae. These methods exploit the specific tinctorial and biophysical properties of amyloids. The methods described here are straightforward and can be easily applied by any modern molecular biology lab for the study of other bacterial amyloids.
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Affiliation(s)
- Margery L Evans
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Elizabeth Gichana
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Yizhou Zhou
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Matthew R Chapman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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62
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Electron microscopic observations of prokaryotic surface appendages. J Microbiol 2017; 55:919-926. [DOI: 10.1007/s12275-017-7369-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 10/10/2017] [Accepted: 10/15/2017] [Indexed: 12/21/2022]
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63
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Zhang Y, Wang A, DeBenedictis EP, Keten S. Bending energy penalty enhances the adhesive strength of functional amyloid curli to surfaces. NANOTECHNOLOGY 2017; 28:464002. [PMID: 28952462 DOI: 10.1088/1361-6528/aa8f72] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The functional amyloid curli fiber, a major proteinaceous component of biofilm extracellular matrices, plays an important role in biofilm formation and enterobacteriaceae adhesion. Curli nanofibers exhibit exceptional underwater adhesion to various surfaces, have high rigidity and strong tensile mechanical properties, and thus hold great promise in biomaterials. The mechanisms of how curli fibers strongly attach to surfaces and detach under force remain elusive. To investigate curli fiber adhesion to surfaces, we developed a coarse-grained curli fiber model, in which the protein subunit CsgA (curli specific gene A) self-assembles into the fiber. The coarse-grained model yields physiologically relevant and tunable bending rigidity and persistence length. The force-induced desorption of a single curli fiber is examined using coarse-grained modeling and theoretical analysis. We find that the bending energy penalty arising from high persistence length enhances the resistance of the curli fiber against desorption and thus strengthens the adhesion of the curli fiber to surfaces. The CsgA-surface adhesion energy and the curli fiber bending rigidity both play crucial roles in the resistance of curli fiber against desorption from surfaces. To enable the desorption process, the applied peeling force must overcome both the interfacial adhesion energy and the energy barrier for bending the curli fiber at the peeling front. We show that the energy barrier to desorption increases with the interfacial adhesion energy, however, the bending induced failure of a single curli fiber limits the work of adhesion if the proportion of the CsgA-surface adhesion energy to the CsgA-CsgA cohesive energy becomes large. These results illustrate that the optimal adhesion performance of nanofibers is dictated by the interplay between bending, surface energy and cohesive energy. Our model provides timely insight into enterobacteriaceae adhesion mechanisms as well as future designs of engineered curli fiber based adhesives.
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Affiliation(s)
- Yao Zhang
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, United States of America
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64
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Pritchard AB, Crean S, Olsen I, Singhrao SK. Periodontitis, Microbiomes and their Role in Alzheimer's Disease. Front Aging Neurosci 2017; 9:336. [PMID: 29114218 PMCID: PMC5660720 DOI: 10.3389/fnagi.2017.00336] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 10/02/2017] [Indexed: 12/11/2022] Open
Abstract
As far back as the eighteenth and early nineteenth centuries, microbial infections were responsible for vast numbers of deaths. The trend reversed with the introduction of antibiotics coinciding with longer life. Increased life expectancy however, accompanied the emergence of age related chronic inflammatory states including the sporadic form of Alzheimer's disease (AD). Taken together, the true challenge of retaining health into later years of life now appears to lie in delaying and/or preventing the progression of chronic inflammatory diseases, through identifying and influencing modifiable risk factors. Diverse pathogens, including periodontal bacteria have been associated with AD brains. Amyloid-beta (Aβ) hallmark protein of AD may be a consequence of infection, called upon due to its antimicrobial properties. Up to this moment in time, a lack of understanding and knowledge of a microbiome associated with AD brain has ensured that the role pathogens may play in this neurodegenerative disease remains unresolved. The oral microbiome embraces a range of diverse bacterial phylotypes, which especially in vulnerable individuals, will excite and perpetuate a range of inflammatory conditions, to a wide range of extra-oral body tissues and organs specific to their developing pathophysiology, including the brain. This offers the tantalizing opportunity that by controlling the oral-specific microbiome; clinicians may treat or prevent a range of chronic inflammatory diseases orally. Evolution has equipped the human host to combat infection/disease by providing an immune system, but Porphyromonas gingivalis and selective spirochetes, have developed immune avoidance strategies threatening the host-microbe homeostasis. It is clear from longitudinal monitoring of patients that chronic periodontitis contributes to declining cognition. The aim here is to discuss the contribution from opportunistic pathogens of the periodontal microbiome, and highlight the challenges, the host faces, when dealing with unresolvable oral infections that may lead to clinical manifestations that are characteristic for AD.
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Affiliation(s)
- Anna B. Pritchard
- Dementia & Neurodegenerative Diseases Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, United Kingdom
| | - StJohn Crean
- Dementia & Neurodegenerative Diseases Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, United Kingdom
| | - Ingar Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - Sim K. Singhrao
- Dementia & Neurodegenerative Diseases Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, United Kingdom
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65
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Tay PKR, Nguyen PQ, Joshi NS. A Synthetic Circuit for Mercury Bioremediation Using Self-Assembling Functional Amyloids. ACS Synth Biol 2017; 6:1841-1850. [PMID: 28737385 DOI: 10.1021/acssynbio.7b00137] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Synthetic biology approaches to bioremediation are a key sustainable strategy to leverage the self-replicating and programmable aspects of biology for environmental stewardship. The increasing spread of anthropogenic mercury pollution into our habitats and food chains is a pressing concern. Here, we explore the use of programmed bacterial biofilms to aid in the sequestration of mercury. We demonstrate that by integrating a mercury-responsive promoter and an operon encoding a mercury-absorbing self-assembling extracellular protein nanofiber, we can engineer bacteria that can detect and sequester toxic Hg2+ ions from the environment. This work paves the way for the development of on-demand biofilm living materials that can operate autonomously as heavy-metal absorbents.
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Affiliation(s)
- Pei Kun R. Tay
- School
of Engineering and Applied Sciences, ‡Wyss Institute for Biologically
Inspired Engineering, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Peter Q. Nguyen
- School
of Engineering and Applied Sciences, ‡Wyss Institute for Biologically
Inspired Engineering, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Neel S. Joshi
- School
of Engineering and Applied Sciences, ‡Wyss Institute for Biologically
Inspired Engineering, Harvard University, Cambridge, Massachusetts 02138, United States
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66
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Dastan A, Frith WJ, Cleaver DJ. Thermal Hysteresis and Seeding of Twisted Fibers Formed by Achiral Discotic Particles. J Phys Chem B 2017; 121:9920-9928. [DOI: 10.1021/acs.jpcb.7b05316] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alireza Dastan
- Materials
and Engineering Research Institute, Sheffield Hallam University, Howard Street, Sheffield S1 1WB, United Kingdom
| | - William J. Frith
- Unilever Discover, Colworth Laboratories, Bedfordshire MK44 1LQ, United Kingdom
| | - Douglas J. Cleaver
- Materials
and Engineering Research Institute, Sheffield Hallam University, Howard Street, Sheffield S1 1WB, United Kingdom
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67
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Zhou G, Peng H, Wang YS, Huang XM, Xie XB, Shi QS. Complete genome sequence of Citrobacter werkmanii strain BF-6 isolated from industrial putrefaction. BMC Genomics 2017; 18:765. [PMID: 29017450 PMCID: PMC5635574 DOI: 10.1186/s12864-017-4157-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/04/2017] [Indexed: 11/10/2022] Open
Abstract
Background In our previous study, Citrobacter werkmanii BF-6 was isolated from an industrial spoilage sample and demonstrated an excellent ability to form biofilms, which could be affected by various environmental factors. However, the genome sequence of this organism has not been reported so far. Results We report the complete genome sequence of C. werkmanii BF-6 together with the description of the genome features and its annotation. The size of the complete chromosome is 4,929,789 bp with an average coverage of 137×. The chromosome exhibits an average G + C content of 52.0%, and encodes 4570 protein coding genes, 84 tRNA genes, 25 rRNA operons, 3 microsatellite sequences and 34 minisatellite sequences. A previously unknown circular plasmid designated as pCW001 was also found with a length of 212,549 bp and a G + C content of 48.2%. 73.5%, 75.6% and 92.6% of the protein coding genes could be assigned to GO Ontology, KEGG Pathway, and COG (Clusters of Orthologous Groups) categories respectively. C. werkmanii BF-6 and C. werkmanii NRBC 105721 exhibited the closest evolutionary relationships based on 16S ribosomal RNA and core-pan genome assay. Furthermore, C. werkmanii BF-6 exhibits typical bacterial biofilm formation and development. In the RT-PCR experiments, we found that a great number of biofilm related genes, such as bsmA, bssR, bssS, hmsP, tabA, csgA, csgB, csgC, csgD, csgE, and csgG, were involved in C. werkmanii BF-6 biofilm formation. Conclusions This is the first complete genome of C. werkmanii. Our work highlights the potential genetic mechanisms involved in biofilm formation and paves a way for further application of C. werkmanii in biofilms research. Electronic supplementary material The online version of this article (10.1186/s12864-017-4157-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gang Zhou
- Guangdong Institute of Microbiology, Guangzhou, Guangdong, 510070, People's Republic of China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, Guangdong, 510070, People's Republic of China.,Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangzhou, Guangdong, 510070, People's Republic of China.,Guangdong Open Laboratory of Applied Microbiology, Guangzhou, Guangdong, 510070, People's Republic of China
| | - Hong Peng
- Guangdong Institute of Microbiology, Guangzhou, Guangdong, 510070, People's Republic of China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, Guangdong, 510070, People's Republic of China.,Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangzhou, Guangdong, 510070, People's Republic of China.,Guangdong Open Laboratory of Applied Microbiology, Guangzhou, Guangdong, 510070, People's Republic of China
| | - Ying-Si Wang
- Guangdong Institute of Microbiology, Guangzhou, Guangdong, 510070, People's Republic of China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, Guangdong, 510070, People's Republic of China.,Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangzhou, Guangdong, 510070, People's Republic of China.,Guangdong Open Laboratory of Applied Microbiology, Guangzhou, Guangdong, 510070, People's Republic of China
| | - Xiao-Mo Huang
- Guangdong Institute of Microbiology, Guangzhou, Guangdong, 510070, People's Republic of China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, Guangdong, 510070, People's Republic of China.,Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangzhou, Guangdong, 510070, People's Republic of China.,Guangdong Open Laboratory of Applied Microbiology, Guangzhou, Guangdong, 510070, People's Republic of China
| | - Xiao-Bao Xie
- Guangdong Institute of Microbiology, Guangzhou, Guangdong, 510070, People's Republic of China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, Guangdong, 510070, People's Republic of China.,Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangzhou, Guangdong, 510070, People's Republic of China.,Guangdong Open Laboratory of Applied Microbiology, Guangzhou, Guangdong, 510070, People's Republic of China
| | - Qing-Shan Shi
- Guangdong Institute of Microbiology, Guangzhou, Guangdong, 510070, People's Republic of China. .,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, Guangdong, 510070, People's Republic of China. .,Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangzhou, Guangdong, 510070, People's Republic of China. .,Guangdong Open Laboratory of Applied Microbiology, Guangzhou, Guangdong, 510070, People's Republic of China.
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68
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Winnacker M. Recent advances in the synthesis of functional materials by engineered and recombinant living cells. SOFT MATTER 2017; 13:6672-6677. [PMID: 28944817 DOI: 10.1039/c7sm01000a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
At the interface of materials science and synthetic biology, several concepts were recently developed for the production of functional materials by living cells. Selected recent strategies for this are highlighted here with a focus on bioactive, electronic and fluorescent materials.
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Affiliation(s)
- Malte Winnacker
- WACKER-Chair of Macromolecular Chemistry and Catalysis Research Center, Technische Universität München, 85747 Garching bei München, Germany.
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69
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Uncharacterized Bacterial Structures Revealed by Electron Cryotomography. J Bacteriol 2017; 199:JB.00100-17. [PMID: 28607161 DOI: 10.1128/jb.00100-17] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/27/2017] [Indexed: 01/06/2023] Open
Abstract
Electron cryotomography (ECT) can reveal the native structure and arrangement of macromolecular complexes inside intact cells. This technique has greatly advanced our understanding of the ultrastructure of bacterial cells. We now view bacteria as structurally complex assemblies of macromolecular machines rather than as undifferentiated bags of enzymes. To date, our group has applied ECT to nearly 90 different bacterial species, collecting more than 15,000 cryotomograms. In addition to known structures, we have observed, to our knowledge, several uncharacterized features in these tomograms. Some are completely novel structures; others expand the features or species range of known structure types. Here, we present a survey of these uncharacterized bacterial structures in the hopes of accelerating their identification and study, and furthering our understanding of the structural complexity of bacterial cells.IMPORTANCE Bacteria are more structurally complex than is commonly appreciated. Here we present a survey of previously uncharacterized structures that we observed in bacterial cells by electron cryotomography, structures that will initiate new lines of research investigating their identities and roles.
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70
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Danielsen HN, Hansen SH, Herbst FA, Kjeldal H, Stensballe A, Nielsen PH, Dueholm MS. Direct Identification of Functional Amyloid Proteins by Label-Free Quantitative Mass Spectrometry. Biomolecules 2017; 7:biom7030058. [PMID: 28777328 PMCID: PMC5618239 DOI: 10.3390/biom7030058] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 07/30/2017] [Accepted: 07/31/2017] [Indexed: 11/16/2022] Open
Abstract
Functional amyloids are important structural and functional components of many biofilms, yet our knowledge of these fascinating polymers is limited to a few examples for which the native amyloids have been isolated in pure form. Isolation of the functional amyloids from other cell components represents a major bottleneck in the search for new functional amyloid systems. Here we present a label-free quantitative mass spectrometry method that allows identification of amyloid proteins directly in cell lysates. The method takes advantage of the extreme structural stability and polymeric nature of functional amyloids and the ability of concentrated formic acid to depolymerize the amyloids. An automated data processing pipeline that provides a short list of amyloid protein candidates was developed based on an amyloid-specific sigmoidal abundance signature in samples treated with increasing concentrations of formic acid. The method was evaluated using the Escherichiacoli curli and the Pseudomonas Fap system. It confidently identified the major amyloid subunit for both systems, as well as the minor subunit for the curli system. A few non-amyloid proteins also displayed the sigmoidal abundance signature. However, only one of these contained a sec-dependent signal peptide, which characterizes most of all secreted proteins, including all currently known functional bacterial amyloids.
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Affiliation(s)
- Heidi N Danielsen
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg, Denmark.
| | - Susan H Hansen
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg, Denmark.
| | - Florian-Alexander Herbst
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg, Denmark.
| | - Henrik Kjeldal
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg, Denmark.
| | - Allan Stensballe
- Department of Health Science and Technology, Aalborg University, 9220 Aalborg, Denmark.
| | - Per H Nielsen
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg, Denmark.
| | - Morten S Dueholm
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg, Denmark.
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71
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Abstract
Curli are functional amyloids produced by proteobacteria like Escherichia coli as part of the extracellular matrix that holds cells together into biofilms. The molecular events that occur during curli nucleation and fiber extension remain largely unknown. Combining observations from curli amyloidogenesis in bulk solutions with real-time in situ nanoscopic imaging at the single-fiber level, we show that curli display polar growth, and we detect two kinetic regimes of fiber elongation. Single fibers exhibit stop-and-go dynamics characterized by bursts of steady-state growth alternated with periods of stagnation. At high subunit concentrations, fibers show constant, unperturbed burst growth. Curli follow a one-step nucleation process in which monomers contemporaneously fold and oligomerize into minimal fiber units that have growth characteristics identical to those of the mature fibrils. Kinetic data and interaction studies of curli fibrillation in the presence of the natural inhibitor CsgC show that the inhibitor binds curli fibers and predominantly acts at the level of fiber elongation.
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72
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Synthetic biology engineering of biofilms as nanomaterials factories. Biochem Soc Trans 2017; 45:585-597. [DOI: 10.1042/bst20160348] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 02/26/2017] [Accepted: 02/28/2017] [Indexed: 11/17/2022]
Abstract
Bottom-up fabrication of nanoscale materials has been a significant focus in materials science for expanding our technological frontiers. This assembly concept, however, is old news to biology — all living organisms fabricate themselves using bottom-up principles through a vast self-organizing system of incredibly complex biomolecules, a marvelous dynamic that we are still attempting to unravel. Can we use what we have gleaned from biology thus far to illuminate alternative strategies for designer nanomaterial manufacturing? In the present review article, new synthetic biology efforts toward using bacterial biofilms as platforms for the synthesis and secretion of programmable nanomaterials are described. Particular focus is given to self-assembling functional amyloids found in bacterial biofilms as re-engineerable modular nanomolecular components. Potential applications and existing challenges for this technology are also explored. This novel approach for repurposing biofilm systems will enable future technologies for using engineered living systems to grow artificial nanomaterials.
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73
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Shafreen RB, Seema S, Ahamed AP, Thajuddin N, Ali Alharbi S. Inhibitory Effect of Biosynthesized Silver Nanoparticles from Extract of Nitzschia palea Against Curli-Mediated Biofilm of Escherichia coli. Appl Biochem Biotechnol 2017; 183:1351-1361. [DOI: 10.1007/s12010-017-2503-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 05/03/2017] [Indexed: 10/19/2022]
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74
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75
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Seker UOS, Chen AY, Citorik RJ, Lu TK. Synthetic Biogenesis of Bacterial Amyloid Nanomaterials with Tunable Inorganic-Organic Interfaces and Electrical Conductivity. ACS Synth Biol 2017; 6:266-275. [PMID: 27794590 PMCID: PMC6422533 DOI: 10.1021/acssynbio.6b00166] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Amyloids are highly ordered, hierarchal protein nanoassemblies. Functional amyloids in bacterial biofilms, such as Escherichia coli curli fibers, are formed by the polymerization of monomeric proteins secreted into the extracellular space. Curli is synthesized by living cells, is primarily composed of the major curlin subunit CsgA, and forms biological nanofibers with high aspect ratios. Here, we explore the application of curli fibers for nanotechnology by engineering curli to mediate tunable biological interfaces with inorganic materials and to controllably form gold nanoparticles and gold nanowires. Specifically, we used cell-synthesized curli fibers as templates for nucleating and growing gold nanoparticles and showed that nanoparticle size could be modulated as a function of curli fiber gold-binding affinity. Furthermore, we demonstrated that gold nanoparticles can be preseeded onto curli fibers and followed by gold enhancement to form nanowires. Using these two approaches, we created artificial cellular systems that integrate inorganic-organic materials to achieve tunable electrical conductivity. We envision that cell-synthesized amyloid nanofibers will be useful for interfacing abiotic and biotic systems to create living functional materials..
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Affiliation(s)
- Urartu Ozgur Safak Seker
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, United States
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
| | - Allen Y. Chen
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, United States
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Robert J. Citorik
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, United States
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- MIT Microbiology Program, 77 Massachusetts Avenue, Cambridge Massachusetts 02139, United States
| | - Timothy K. Lu
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, United States
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- MIT Microbiology Program, 77 Massachusetts Avenue, Cambridge Massachusetts 02139, United States
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76
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Naidoo N, Pillay M. Bacterial pili, with emphasis on Mycobacterium tuberculosis curli pili: potential biomarkers for point-of care tests and therapeutics. Biomarkers 2016; 22:93-105. [PMID: 27797276 DOI: 10.1080/1354750x.2016.1252960] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
CONTEXT Novel biomarkers are essential for developing rapid diagnostics and therapeutic interventions Objective: This review aimed to highlight biomarker characterisation and assessment of unique bacterial pili. METHODS A PubMed search for bacterial pili, diagnostics, vaccine and therapeutics was performed, with emphasis on the well characterised pili. RESULTS In total, 46 papers were identified and reviewed. CONCLUSION Extensive analyses of pili enabled by advanced nanotechnology and whole genome sequencing provide evidence that they are strong biomarker candidates. Mycobacterium tuberculosis curli pili are emphasised as important epitopes for the development of much needed point-of-care diagnostics and therapeutics.
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Affiliation(s)
- Natasha Naidoo
- a Medical Microbiology and Infection Control , School of Laboratory Medicine and Medical Sciences, College of Health Science, University of KwaZulu-Natal, Congella , Durban , South Africa
| | - Manormoney Pillay
- a Medical Microbiology and Infection Control , School of Laboratory Medicine and Medical Sciences, College of Health Science, University of KwaZulu-Natal, Congella , Durban , South Africa
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77
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Stenvang M, Dueholm MS, Vad BS, Seviour T, Zeng G, Geifman-Shochat S, Søndergaard MT, Christiansen G, Meyer RL, Kjelleberg S, Nielsen PH, Otzen DE. Epigallocatechin Gallate Remodels Overexpressed Functional Amyloids in Pseudomonas aeruginosa and Increases Biofilm Susceptibility to Antibiotic Treatment. J Biol Chem 2016; 291:26540-26553. [PMID: 27784787 DOI: 10.1074/jbc.m116.739953] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 10/07/2016] [Indexed: 01/09/2023] Open
Abstract
Epigallocatechin-3-gallate (EGCG) is the major polyphenol in green tea. It has antimicrobial properties and disrupts the ordered structure of amyloid fibrils involved in human disease. The antimicrobial effect of EGCG against the opportunistic pathogen Pseudomonas aeruginosa has been shown to involve disruption of quorum sensing (QS). Functional amyloid fibrils in P. aeruginosa (Fap) are able to bind and retain quorum-sensing molecules, suggesting that EGCG interferes with QS through structural remodeling of amyloid fibrils. Here we show that EGCG inhibits the ability of Fap to form fibrils; instead, EGCG stabilizes protein oligomers. Existing fibrils are remodeled by EGCG into non-amyloid aggregates. This fibril remodeling increases the binding of pyocyanin, demonstrating a mechanism by which EGCG can affect the QS function of functional amyloid. EGCG reduced the amyloid-specific fluorescent thioflavin T signal in P. aeruginosa biofilms at concentrations known to exert an antimicrobial effect. Nanoindentation studies showed that EGCG reduced the stiffness of biofilm containing Fap fibrils but not in biofilm with little Fap. In a combination treatment with EGCG and tobramycin, EGCG had a moderate effect on the minimum bactericidal eradication concentration against wild-type P. aeruginosa biofilms, whereas EGCG had a more pronounced effect when Fap was overexpressed. Our results provide a direct molecular explanation for the ability of EGCG to disrupt P. aeruginosa QS and modify its biofilm and strengthens the case for EGCG as a candidate in multidrug treatment of persistent biofilm infections.
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Affiliation(s)
- Marcel Stenvang
- From the Interdisciplinary Nanoscience Center (iNANO).,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN).,the Sino-Danish Centre for Education and Research (SDC), 8000 Aarhus C, Denmark
| | - Morten S Dueholm
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark
| | - Brian S Vad
- From the Interdisciplinary Nanoscience Center (iNANO).,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN)
| | - Thomas Seviour
- the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore
| | | | - Susana Geifman-Shochat
- the School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore, and
| | - Mads T Søndergaard
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark
| | | | - Rikke Louise Meyer
- From the Interdisciplinary Nanoscience Center (iNANO).,the Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Staffan Kjelleberg
- the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore.,the Centre for Marine Bio-innovation and School of Biotechnology and Biomolecular Science, University of New South Wales, Mosman, New South Wales 2088, Australia
| | - Per Halkjær Nielsen
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark.,the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore
| | - Daniel E Otzen
- From the Interdisciplinary Nanoscience Center (iNANO), .,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN)
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78
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Abstract
Recent insights into bacterial biofilm matrix structures have induced a paradigm shift toward the recognition of amyloid fibers as common building block structures that confer stability to the exopolysaccharide matrix. Here we describe the functional amyloid systems related to biofilm matrix formation in both Gram-negative and Gram-positive bacteria and recent knowledge regarding the interaction of amyloids with other biofilm matrix components such as extracellular DNA (eDNA) and the host immune system. In addition, we summarize the efforts to identify compounds that target amyloid fibers for therapeutic purposes and recent developments that take advantage of the amyloid structure to engineer amyloid fibers of bacterial biofilm matrices for biotechnological applications.
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79
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The curli biogenesis genes expression level is unassociated with Enterobacter cloacae hsp60 clusters and PFGE genotypes. Microb Pathog 2016; 98:112-7. [DOI: 10.1016/j.micpath.2016.06.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/16/2016] [Accepted: 06/24/2016] [Indexed: 11/19/2022]
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80
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Abstract
Amyloid formation has been most studied in the context of neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease, as well as in amyloidosis. However, it is becoming increasingly clear that amyloid is also present in the healthy setting; for example nontoxic amyloid formation is important for melanin synthesis and in innate immunity. Furthermore, bacteria have mechanisms to produce functional amyloid structures with important roles in bacterial physiology and interaction with host cells. Here, we will discuss some novel aspects of fibril-forming proteins in humans and bacteria. First, the amyloid-forming properties of the antimicrobial peptide human defensin 6 (HD6) will be considered. Intriguingly, unlike other antimicrobial peptides, HD6 does not kill bacteria. However, recent data show that HD6 can form amyloid structures at the gut mucosa with strong affinity for bacterial surfaces. These so-called nanonets block bacterial invasion by entangling the bacteria in net-like structures. Next, the role of functional amyloid fibrils in human semen will be discussed. These fibrils were discovered through their property to enhance HIV infection but they may also have other yet unknown functions. Finally, the role of amyloid formation in bacteria will be reviewed. The recent finding that bacteria can make amyloid in a controlled fashion without toxic effects is of particular interest and may have implications for human disease. The role of amyloid in health and disease is beginning to be unravelled, and here, we will review some of the most recent findings in this exciting area.
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Affiliation(s)
- P Bergman
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - N R Roan
- Department of Urology, University of California, San Francisco, CA, USA.,The J. David Gladstone Institutes, San Francisco, CA, USA
| | - U Römling
- Department of Microbiology, Tumor and Cellbiology, Karolinska Institutet, Stockholm, Sweden
| | - C L Bevins
- Department of Microbiology and Immunology, School of Medicine, University of California, Davis, CA, USA
| | - J Münch
- Institute of Molecular Virology, Ulm University Medical Centre, Ulm, Germany.,Ulm Peptide Pharmaceuticals, Ulm University, Ulm, Germany
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81
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Taylor JD, Hawthorne WJ, Lo J, Dear A, Jain N, Meisl G, Andreasen M, Fletcher C, Koch M, Darvill N, Scull N, Escalera-Maurer A, Sefer L, Wenman R, Lambert S, Jean J, Xu Y, Turner B, Kazarian SG, Chapman MR, Bubeck D, de Simone A, Knowles TPJ, Matthews SJ. Electrostatically-guided inhibition of Curli amyloid nucleation by the CsgC-like family of chaperones. Sci Rep 2016; 6:24656. [PMID: 27098162 PMCID: PMC4838910 DOI: 10.1038/srep24656] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 03/29/2016] [Indexed: 11/16/2022] Open
Abstract
Polypeptide aggregation into amyloid is linked with several debilitating human diseases. Despite the inherent risk of aggregation-induced cytotoxicity, bacteria control the export of amyloid-prone subunits and assemble adhesive amyloid fibres during biofilm formation. An Escherichia protein, CsgC potently inhibits amyloid formation of curli amyloid proteins. Here we unlock its mechanism of action, and show that CsgC strongly inhibits primary nucleation via electrostatically-guided molecular encounters, which expands the conformational distribution of disordered curli subunits. This delays the formation of higher order intermediates and maintains amyloidogenic subunits in a secretion-competent form. New structural insight also reveal that CsgC is part of diverse family of bacterial amyloid inhibitors. Curli assembly is therefore not only arrested in the periplasm, but the preservation of conformational flexibility also enables efficient secretion to the cell surface. Understanding how bacteria safely handle amyloidogenic polypeptides contribute towards efforts to control aggregation in disease-causing amyloids and amyloid-based biotechnological applications.
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Affiliation(s)
- Jonathan D Taylor
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | | | - Joanne Lo
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Alexander Dear
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Neha Jain
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Georg Meisl
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Maria Andreasen
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Catherine Fletcher
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Marion Koch
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Nicholas Darvill
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Nicola Scull
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | | | - Lea Sefer
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Rosemary Wenman
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Sebastian Lambert
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Jisoo Jean
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Yingqi Xu
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Benjamin Turner
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Sergei G Kazarian
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Matthew R Chapman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Doryen Bubeck
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Alfonso de Simone
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Tuomas P J Knowles
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Steve J Matthews
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
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82
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Abstract
Escherichia coli is one of the world's best-characterized organisms, because it has been extensively studied for over a century. However, most of this work has focused on E. coli grown under laboratory conditions that do not faithfully simulate its natural environments. Therefore, the historical perspectives on E. coli physiology and life cycle are somewhat skewed toward experimental systems that feature E. coli growing logarithmically in a test tube. Typically a commensal bacterium, E. coli resides in the lower intestines of a slew of animals. Outside of the lower intestine, E. coli can adapt and survive in a very different set of environmental conditions. Biofilm formation allows E. coli to survive, and even thrive, in environments that do not support the growth of planktonic populations. E. coli can form biofilms virtually everywhere: in the bladder during a urinary tract infection, on in-dwelling medical devices, and outside of the host on plants and in the soil. The E. coli extracellular matrix (ECM), primarily composed of the protein polymer named curli and the polysaccharide cellulose, promotes adherence to organic and inorganic surfaces and resistance to desiccation, the host immune system, and other antimicrobials. The pathways that govern E. coli biofilm formation, cellulose production, and curli biogenesis will be discussed in this article, which concludes with insights into the future of E. coli biofilm research and potential therapies.
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83
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Abstract
During the first step of biofilm formation, initial attachment is dictated by physicochemical and electrostatic interactions between the surface and the bacterial envelope. Depending on the nature of these interactions, attachment can be transient or permanent. To achieve irreversible attachment, bacterial cells have developed a series of surface adhesins promoting specific or nonspecific adhesion under various environmental conditions. This article reviews the recent advances in our understanding of the secretion, assembly, and regulation of the bacterial adhesins during biofilm formation, with a particular emphasis on the fimbrial, nonfimbrial, and discrete polysaccharide adhesins in Gram-negative bacteria.
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84
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Akbari M, Bakhshi B, Najar Peerayeh S, Behmanesh M. Detection of Curli Biogenesis Genes Among Enterobacter cloacae Isolated From Blood Cultures. INTERNATIONAL JOURNAL OF ENTERIC PATHOGENS 2015. [DOI: 10.17795/ijep28413] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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85
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Biofilm-associated bacterial amyloids dampen inflammation in the gut: oral treatment with curli fibres reduces the severity of hapten-induced colitis in mice. NPJ Biofilms Microbiomes 2015; 1. [PMID: 26855788 PMCID: PMC4739805 DOI: 10.1038/npjbiofilms.2015.19] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Background/objectives: A disruption of epithelial barrier function can lead to intestinal inflammation. Toll-like receptor (TLR) 2 activation by microbial products promotes intestinal epithelial integrity and overall gut health. Several bacterial species, including enteric bacteria, actively produce amyloid proteins as a part of their biofilms. Recognition of amyloid fibres found in enteric biofilms, termed curli, by the Toll-like receptor (TLR)2/1 complex reinforces barrier function. Here, we investigated the effect of purified curli fibres on inflammation in a mouse model of acute colitis. Methods: Bone marrow–derived macrophages as well as lamina propria cells were treated with curli fibres of both pathogenic Salmonella enterica serovar Typhimurium and commensal Escherichia coli Nissle 1917 biofilms. Mice were given 0.1 or 0.4 mg of purified curli orally 1 day post administration of 1% 2,4,6-trinitrobenzene sulphonic acid (TNBS) enema. Histopathological analysis was performed on distal colonic tissue taken 6 days post TNBS enema. RNA extracted from colonic tissue was subjected to RT-PCR. Results: Here we show that curli fibres of both pathogenic and commensal bacteria are recognised by TLR2 leading to the production of IL-10, immunomodulatory cytokine of intestinal homeostasis. Treatment of mice with a single dose of curli heightens transcript levels of Il10 in the colon and ameliorates the disease pathology in TNBS-induced colitis. Curli treatment is comparable to the treatment with anti-tumour necrosis factor alpha (anti-TNFα) antibodies, a treatment known to reduce the severity of acute colitis in humans and mice. Conclusion: These results suggest that the bacterial amyloids had a role in helping to maintain immune homeostasis in the intestinal mucosa via the TLR2/IL-10 axis. Furthermore, bacterial amyloids may be a potential candidate therapeutic to treat intestinal inflammatory disorders owing to their remarkable immunomodulatory activity.
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86
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Choudhury JD, Pramanik A, Webster NS, Llewellyn LE, Gachhui R, Mukherjee J. The Pathogen of the Great Barrier Reef Sponge Rhopaloeides odorabile Is a New Strain of Pseudoalteromonas agarivorans Containing Abundant and Diverse Virulence-Related Genes. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2015; 17:463-78. [PMID: 25837832 DOI: 10.1007/s10126-015-9627-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 03/11/2015] [Indexed: 05/20/2023]
Abstract
Sponge diseases have increased dramatically, yet the causative agents of disease outbreaks have eluded identification. We undertook a polyphasic taxonomic analysis of the only confirmed sponge pathogen and identified it as a novel strain of Pseudoalteromonas agarivorans. 16S ribosomal RNA (rRNA) and gyraseB (gyrB) gene sequences along with phenotypic characteristics demonstrated that strain NW4327 was most closely related to P. agarivorans. DNA-DNA hybridization and in silico genome comparisons established NW4327 as a novel strain of P. agarivorans. Genes associated with type IV pili, mannose-sensitive hemagglutinin pili, and curli formation were identified in NW4327. One gene cluster encoding ATP-binding cassette (ABC) transporter, HlyD and TolC, and two clusters related to the general secretion pathway indicated the presence of type I secretion system (T1SS) and type II secretion system (T2SS), respectively. A contiguous gene cluster of at least 19 genes related to type VI secretion system (T6SS) which included all 13 core genes was found. The absence of T1SS and T6SS in nonpathogenic P. agarivorans S816 established NW4327 as the virulent strain. Serine proteases and metalloproteases of the classes S8, S9, M4, M6, M48, and U32 were identified in NW4327, many of which can degrade collagen. Collagenase activity in NW4327 and its absence in the nonpathogenic P. agarivorans KMM 255(T) reinforced the invasiveness of NW4327. This is the first report unambiguously identifying a sponge pathogen and providing the first insights into the virulence genes present in any pathogenic Pseudoalteromonas genome. The investigation supports a theoretical study predicting high abundance of terrestrial virulence gene homologues in marine bacteria.
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Affiliation(s)
- Jayanta D Choudhury
- School of Environmental Studies, Jadavpur University, Kolkata, 700 032, India
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87
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Dueholm MS, Larsen P, Finster K, Stenvang MR, Christiansen G, Vad BS, Bøggild A, Otzen DE, Nielsen PH. The Tubular Sheaths Encasing Methanosaeta thermophila Filaments Are Functional Amyloids. J Biol Chem 2015; 290:20590-600. [PMID: 26109065 DOI: 10.1074/jbc.m115.654780] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Indexed: 11/06/2022] Open
Abstract
Archaea are renowned for their ability to thrive in extreme environments, although they can be found in virtually all habitats. Their adaptive success is linked to their unique cell envelopes that are extremely resistant to chemical and thermal denaturation and that resist proteolysis by common proteases. Here we employ amyloid-specific conformation antibodies and biophysical techniques to show that the extracellular cell wall sheaths encasing the methanogenic archaea Methanosaeta thermophila PT are functional amyloids. Depolymerization of sheaths and subsequent MS/MS analyses revealed that the sheaths are composed of a single major sheath protein (MspA). The amyloidogenic nature of MspA was confirmed by in vitro amyloid formation of recombinant MspA under a wide range of environmental conditions. This is the first report of a functional amyloid from the archaeal domain of life. The amyloid nature explains the extreme resistance of the sheath, the elastic properties that allow diffusible substrates to penetrate through expandable hoop boundaries, and how the sheaths are able to split and elongate outside the cell. The archaeal sheath amyloids do not share homology with any of the currently known functional amyloids and clearly represent a new function of the amyloid protein fold.
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Affiliation(s)
- Morten S Dueholm
- From the Center for Microbial Communities, Department of Chemistry and Biosciences, Aalborg University, 9220 Aalborg, Denmark
| | - Poul Larsen
- From the Center for Microbial Communities, Department of Chemistry and Biosciences, Aalborg University, 9220 Aalborg, Denmark
| | | | - Marcel R Stenvang
- the Interdisciplinary Nanoscience Center (iNANO) and Center for Insoluble Protein Structures (inSPIN), the Department of Molecular Biology and Genetics, and
| | | | - Brian S Vad
- the Interdisciplinary Nanoscience Center (iNANO) and Center for Insoluble Protein Structures (inSPIN), the Department of Molecular Biology and Genetics, and
| | | | - Daniel E Otzen
- the Interdisciplinary Nanoscience Center (iNANO) and Center for Insoluble Protein Structures (inSPIN), the Department of Molecular Biology and Genetics, and
| | - Per Halkjær Nielsen
- From the Center for Microbial Communities, Department of Chemistry and Biosciences, Aalborg University, 9220 Aalborg, Denmark,
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88
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Gallo PM, Rapsinski GJ, Wilson RP, Oppong GO, Sriram U, Goulian M, Buttaro B, Caricchio R, Gallucci S, Tükel Ç. Amyloid-DNA Composites of Bacterial Biofilms Stimulate Autoimmunity. Immunity 2015; 42:1171-84. [PMID: 26084027 PMCID: PMC4500125 DOI: 10.1016/j.immuni.2015.06.002] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 12/08/2014] [Accepted: 04/06/2015] [Indexed: 01/13/2023]
Abstract
Research on the human microbiome has established that commensal and pathogenic bacteria can influence obesity, cancer, and autoimmunity through mechanisms mostly unknown. We found that a component of bacterial biofilms, the amyloid protein curli, irreversibly formed fibers with bacterial DNA during biofilm formation. This interaction accelerated amyloid polymerization and created potent immunogenic complexes that activated immune cells, including dendritic cells, to produce cytokines such as type I interferons, which are pathogenic in systemic lupus erythematosus (SLE). When given systemically, curli-DNA composites triggered immune activation and production of autoantibodies in lupus-prone and wild-type mice. We also found that the infection of lupus-prone mice with curli-producing bacteria triggered higher autoantibody titers compared to curli-deficient bacteria. These data provide a mechanism by which the microbiome and biofilm-producing enteric infections may contribute to the progression of SLE and point to a potential molecular target for treatment of autoimmunity.
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Affiliation(s)
- Paul M Gallo
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA; Laboratory of Dendritic Cell Biology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA
| | - Glenn J Rapsinski
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA
| | - R Paul Wilson
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA
| | - Gertrude O Oppong
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA
| | - Uma Sriram
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA; Laboratory of Dendritic Cell Biology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA
| | - Mark Goulian
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Bettina Buttaro
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA
| | - Roberto Caricchio
- Division of Rheumatology, Department of Medicine, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA
| | - Stefania Gallucci
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA; Laboratory of Dendritic Cell Biology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA
| | - Çagla Tükel
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA.
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89
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Hobley L, Harkins C, MacPhee CE, Stanley-Wall NR. Giving structure to the biofilm matrix: an overview of individual strategies and emerging common themes. FEMS Microbiol Rev 2015; 39:649-69. [PMID: 25907113 PMCID: PMC4551309 DOI: 10.1093/femsre/fuv015] [Citation(s) in RCA: 344] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2015] [Indexed: 01/24/2023] Open
Abstract
Biofilms are communities of microbial cells that underpin diverse processes including sewage bioremediation, plant growth promotion, chronic infections and industrial biofouling. The cells resident in the biofilm are encased within a self-produced exopolymeric matrix that commonly comprises lipids, proteins that frequently exhibit amyloid-like properties, eDNA and exopolysaccharides. This matrix fulfils a variety of functions for the community, from providing structural rigidity and protection from the external environment to controlling gene regulation and nutrient adsorption. Critical to the development of novel strategies to control biofilm infections, or the capability to capitalize on the power of biofilm formation for industrial and biotechnological uses, is an in-depth knowledge of the biofilm matrix. This is with respect to the structure of the individual components, the nature of the interactions between the molecules and the three-dimensional spatial organization. We highlight recent advances in the understanding of the structural and functional role that carbohydrates and proteins play within the biofilm matrix to provide three-dimensional architectural integrity and functionality to the biofilm community. We highlight, where relevant, experimental techniques that are allowing the boundaries of our understanding of the biofilm matrix to be extended using Escherichia coli, Staphylococcus aureus, Vibrio cholerae, and Bacillus subtilis as exemplars. Examining the structure and function of the biofilm extracellular matrix.
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Affiliation(s)
- Laura Hobley
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Catriona Harkins
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Cait E MacPhee
- James Clerk Maxwell Building, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, UK
| | - Nicola R Stanley-Wall
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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90
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Taylor JD, Matthews SJ. New insight into the molecular control of bacterial functional amyloids. Front Cell Infect Microbiol 2015; 5:33. [PMID: 25905048 PMCID: PMC4389571 DOI: 10.3389/fcimb.2015.00033] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 03/19/2015] [Indexed: 11/16/2022] Open
Abstract
Amyloid protein structure has been discovered in a variety of functional or pathogenic contexts. What distinguishes the former from the latter is that functional amyloid systems possess dedicated molecular control systems that determine the timing, location, and structure of the fibers. Failure to guide this process can result in cytotoxicity, as observed in several pathologies like Alzheimer's and Parkinson's Disease. Many gram-negative bacteria produce an extracellular amyloid fiber known as curli via a multi-component secretion system. During this process, aggregation-prone, semi-folded curli subunits have to cross the periplasm and outer-membrane and self-assemble into surface-attached fibers. Two recent breakthroughs have provided molecular details regarding periplasmic chaperoning and subunit secretion. This review offers a combined perspective on these first mechanistic insights into the curli system.
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Affiliation(s)
- Jonathan D Taylor
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College of Science, Technology and Medicine London, UK
| | - Steve J Matthews
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College of Science, Technology and Medicine London, UK
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91
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Evans ML, Chorell E, Taylor JD, Åden J, Götheson A, Li F, Koch M, Sefer L, Matthews SJ, Wittung-Stafshede P, Almqvist F, Chapman MR. The bacterial curli system possesses a potent and selective inhibitor of amyloid formation. Mol Cell 2015; 57:445-55. [PMID: 25620560 PMCID: PMC4320674 DOI: 10.1016/j.molcel.2014.12.025] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 10/28/2014] [Accepted: 12/16/2014] [Indexed: 12/22/2022]
Abstract
Curli are extracellular functional amyloids that are assembled by enteric bacteria during biofilm formation and host colonization. An efficient secretion system and chaperone network ensures that the major curli fiber subunit, CsgA, does not form intracellular amyloid aggregates. We discovered that the periplasmic protein CsgC was a highly effective inhibitor of CsgA amyloid formation. In the absence of CsgC, CsgA formed toxic intracellular aggregates. In vitro, CsgC inhibited CsgA amyloid formation at substoichiometric concentrations and maintained CsgA in a non-β-sheet-rich conformation. Interestingly, CsgC inhibited amyloid assembly of human α-synuclein, but not Aβ42, in vitro. We identified a common D-Q-Φ-X0,1-G-K-N-ζ-E motif in CsgC client proteins that is not found in Aβ42. CsgC is therefore both an efficient and selective amyloid inhibitor. Dedicated functional amyloid inhibitors may be a key feature that distinguishes functional amyloids from disease-associated amyloids.
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Affiliation(s)
- Margery L Evans
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Erik Chorell
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Jonathan D Taylor
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Jörgen Åden
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Anna Götheson
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Fei Li
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Marion Koch
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Lea Sefer
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Steve J Matthews
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | | | - Fredrik Almqvist
- Centre for Microbial Research, Umeå University, 901 87 Umeå, Sweden; Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Matthew R Chapman
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA; Centre for Microbial Research, Umeå University, 901 87 Umeå, Sweden.
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92
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Seviour T, Hansen SH, Yang L, Yau YH, Wang VB, Stenvang MR, Christiansen G, Marsili E, Givskov M, Chen Y, Otzen DE, Nielsen PH, Geifman-Shochat S, Kjelleberg S, Dueholm MS. Functional amyloids keep quorum-sensing molecules in check. J Biol Chem 2015; 290:6457-69. [PMID: 25586180 DOI: 10.1074/jbc.m114.613810] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The mechanism by which extracellular metabolites, including redox mediators and quorum-sensing signaling molecules, traffic through the extracellular matrix of biofilms is poorly explored. We hypothesize that functional amyloids, abundant in natural biofilms and possessing hydrophobic domains, retain these metabolites. Using surface plasmon resonance, we demonstrate that the quorum-sensing (QS) molecules, 2-heptyl-3-hydroxy-4(1H)-quinolone and N-(3-oxododecanoyl)-l-homoserine lactone, and the redox mediator pyocyanin bind with transient affinity to functional amyloids from Pseudomonas (Fap). Their high hydrophobicity predisposes them to signal-amyloid interactions, but specific interactions also play a role. Transient interactions allow for rapid association and dissociation kinetics, which make the QS molecules bioavailable and at the same time secure within the extracellular matrix as a consequence of serial bindings. Retention of the QS molecules was confirmed using Pseudomonas aeruginosa PAO1-based 2-heptyl-3-hydroxy-4(1H)-quinolone and N-(3-oxododecanoyl)-l-homoserine lactone reporter assays, showing that Fap fibrils pretreated with the QS molecules activate the reporters even after sequential washes. Pyocyanin retention was validated by electrochemical analysis of pyocyanin-pretreated Fap fibrils subjected to the same washing process. Results suggest that QS molecule-amyloid interactions are probably important in the turbulent environments commonly encountered in natural habitats.
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Affiliation(s)
- Thomas Seviour
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and
| | - Susan Hove Hansen
- the Center for Microbial Communities, Aalborg University, 9220 Aalborg East, Denmark
| | - Liang Yang
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and
| | - Yin Hoe Yau
- the School of Biological Sciences (SBS), Nanyang Technological University, Singapore 637551, Singapore
| | - Victor Bochuan Wang
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and the School of Materials Science and Engineering (MSE), Nanyang Technological University, Singapore 639798
| | - Marcel R Stenvang
- the Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN), and
| | - Gunna Christiansen
- the Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Enrico Marsili
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and
| | - Michael Givskov
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and the Department of International Health, Immunology and Microbiology, University of Copenhagen, 1165 Copenhagen, Denmark, and
| | - Yicai Chen
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and
| | - Daniel E Otzen
- the Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN), and
| | - Per Halkjær Nielsen
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and the Center for Microbial Communities, Aalborg University, 9220 Aalborg East, Denmark
| | - Susana Geifman-Shochat
- the School of Biological Sciences (SBS), Nanyang Technological University, Singapore 637551, Singapore
| | - Staffan Kjelleberg
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and the Centre for Marine Bio-innovation and School of Biotechnology and Biomolecular Science, University of New South Wales, Mosman, New South Wales 2088, Australia
| | - Morten S Dueholm
- the Center for Microbial Communities, Aalborg University, 9220 Aalborg East, Denmark
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93
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Structural and mechanistic insights into the bacterial amyloid secretion channel CsgG. Nature 2014; 516:250-3. [PMID: 25219853 DOI: 10.1038/nature13768] [Citation(s) in RCA: 202] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 08/13/2014] [Indexed: 11/09/2022]
Abstract
Curli are functional amyloid fibres that constitute the major protein component of the extracellular matrix in pellicle biofilms formed by Bacteroidetes and Proteobacteria (predominantly of the α and γ classes). They provide a fitness advantage in pathogenic strains and induce a strong pro-inflammatory response during bacteraemia. Curli formation requires a dedicated protein secretion machinery comprising the outer membrane lipoprotein CsgG and two soluble accessory proteins, CsgE and CsgF. Here we report the X-ray structure of Escherichia coli CsgG in a non-lipidated, soluble form as well as in its native membrane-extracted conformation. CsgG forms an oligomeric transport complex composed of nine anticodon-binding-domain-like units that give rise to a 36-stranded β-barrel that traverses the bilayer and is connected to a cage-like vestibule in the periplasm. The transmembrane and periplasmic domains are separated by a 0.9-nm channel constriction composed of three stacked concentric phenylalanine, asparagine and tyrosine rings that may guide the extended polypeptide substrate through the secretion pore. The specificity factor CsgE forms a nonameric adaptor that binds and closes off the periplasmic face of the secretion channel, creating a 24,000 Å(3) pre-constriction chamber. Our structural, functional and electrophysiological analyses imply that CsgG is an ungated, non-selective protein secretion channel that is expected to employ a diffusion-based, entropy-driven transport mechanism.
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94
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Complete Genome Sequence of Pseudomonas sp. UK4, a Model Organism for Studies of Functional Amyloids in Pseudomonas. GENOME ANNOUNCEMENTS 2014; 2:2/5/e00898-14. [PMID: 25212622 PMCID: PMC4161751 DOI: 10.1128/genomea.00898-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Here, we present the complete genome of Pseudomonas sp. UK4. This bacterium was the first Pseudomonas strain shown to produce functional amyloids, and it represents a model organism for studies of functional amyloids in Pseudomonas (Fap).
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95
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Biofilm formation protects Escherichia coli against killing by Caenorhabditis elegans and Myxococcus xanthus. Appl Environ Microbiol 2014; 80:7079-87. [PMID: 25192998 DOI: 10.1128/aem.02464-14] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Enteric bacteria, such as Escherichia coli, are exposed to a variety of stresses in the nonhost environment. The development of biofilms provides E. coli with resistance to environmental insults, such as desiccation and bleach. We found that biofilm formation, specifically production of the matrix components curli and cellulose, protected E. coli against killing by the soil-dwelling nematode Caenorhabditis elegans and the predatory bacterium Myxococcus xanthus. Additionally, matrix-encased bacteria at the air-biofilm interface exhibited ∼40-fold-increased survival after C. elegans and M. xanthus killing compared to the non-matrix-encased cells that populate the interior of the biofilm. To determine if nonhost Enterobacteriaceae reservoirs supported biofilm formation, we grew E. coli on media composed of pig dung or commonly contaminated foods, such as beef, chicken, and spinach. Each of these medium types provided a nutritional environment that supported matrix production and biofilm formation. Altogether, we showed that common, nonhost reservoirs of E. coli supported the formation of biofilms that subsequently protected E. coli against predation.
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96
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Simon NC, Aktories K, Barbieri JT. Novel bacterial ADP-ribosylating toxins: structure and function. Nat Rev Microbiol 2014; 12:599-611. [PMID: 25023120 PMCID: PMC5846498 DOI: 10.1038/nrmicro3310] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Bacterial ADP-ribosyltransferase toxins (bARTTs) transfer ADP-ribose to eukaryotic proteins to promote bacterial pathogenesis. In this Review, we use prototype bARTTs, such as diphtheria toxin and pertussis toxin, as references for the characterization of several new bARTTs from human, insect and plant pathogens, which were recently identified by bioinformatic analyses. Several of these toxins, including cholix toxin (ChxA) from Vibrio cholerae, SpyA from Streptococcus pyogenes, HopU1 from Pseudomonas syringae and the Tcc toxins from Photorhabdus luminescens, ADP-ribosylate novel substrates and have unique organizations, which distinguish them from the reference toxins. The characterization of these toxins increases our appreciation of the range of structural and functional properties that are possessed by bARTTs and their roles in bacterial pathogenesis.
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Affiliation(s)
- Nathan C. Simon
- Medical College of Wisconsin, Microbiology and Molecular Genetics, Milwaukee, WI, USA
| | - Klaus Aktories
- Institute of Experimental and Clinical Pharmacology and Toxicology; Albert-Ludwigs-University Freiburg; Freiburg, Germany
| | - Joseph T. Barbieri
- Medical College of Wisconsin, Microbiology and Molecular Genetics, Milwaukee, WI, USA
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97
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The disulfide bonding system suppresses CsgD-independent cellulose production in Escherichia coli. J Bacteriol 2014; 196:3690-9. [PMID: 25112475 DOI: 10.1128/jb.02019-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The bacterial extracellular matrix encases cells and protects them from host-related and environmental insults. The Escherichia coli master biofilm regulator CsgD is required for the production of the matrix components curli and cellulose. CsgD activates the diguanylate cyclase AdrA, which in turn stimulates cellulose production through cyclic di-GMP (c-di-GMP). Here, we identified and characterized a CsgD- and AdrA-independent cellulose production pathway that was maximally active when cultures were grown under reducing conditions or when the disulfide bonding system (DSB) was compromised. The CsgD-independent cellulose activation pathway was dependent on a second diguanylate cyclase, called YfiN. c-di-GMP production by YfiN was repressed by the periplasmic protein YfiR, and deletion of yfiR promoted CsgD-independent cellulose production. Conversely, when YfiR was overexpressed, cellulose production was decreased. Finally, we found that YfiR was oxidized by DsbA and that intraprotein YfiR disulfide bonds stabilized YfiR in the periplasm. Altogether, we showed that reducing conditions and mutations in the DSB system caused hyperactivation of YfiN and subsequent CsgD-independent cellulose production.
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98
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Evans ML, Chapman MR. Curli biogenesis: order out of disorder. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1843:1551-8. [PMID: 24080089 PMCID: PMC4243835 DOI: 10.1016/j.bbamcr.2013.09.010] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 09/18/2013] [Accepted: 09/19/2013] [Indexed: 10/26/2022]
Abstract
Many bacteria assemble extracellular amyloid fibers on their cell surface. Secretion of proteins across membranes and the assembly of complex macromolecular structures must be highly coordinated to avoid the accumulation of potentially toxic intracellular protein aggregates. Extracellular amyloid fiber assembly poses an even greater threat to cellular health due to the highly aggregative nature of amyloids and the inherent toxicity of amyloid assembly intermediates. Therefore, temporal and spatial control of amyloid protein secretion is paramount. The biogenesis and assembly of the extracellular bacterial amyloid curli is an ideal system for studying how bacteria cope with the many challenges of controlled and ordered amyloid assembly. Here, we review the recent progress in the curli field that has made curli biogenesis one of the best-understood functional amyloid assembly pathways. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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Affiliation(s)
- Margery L Evans
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109, USA
| | - Matthew R Chapman
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109, USA.
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99
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Complete Genome Sequences of Pseudomonas monteilii SB3078 and SB3101, Two Benzene-, Toluene-, and Ethylbenzene-Degrading Bacteria Used for Bioaugmentation. GENOME ANNOUNCEMENTS 2014; 2:2/3/e00524-14. [PMID: 24874689 PMCID: PMC4038894 DOI: 10.1128/genomea.00524-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Pseudomonas monteilii SB3078 and SB3101 are benzene-, toluene-, and ethylbenzene-degrading strains used for bioaugmentation in relation to treatment of wastewater contaminated with petrochemical hydrocarbons. Complete genome sequencing of the bioaugmentation strains confirms that they are very closely related (100.0% average nucleotide identity). Both strains contain extensive integration of phage elements, with the main difference being insertion of additional phage elements in the SB3078 genome.
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100
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Abstract
The conformational diseases, linked to protein aggregation into amyloid conformations, range from non-infectious neurodegenerative disorders, such as Alzheimer disease (AD), to highly infectious ones, such as human transmissible spongiform encephalopathies (TSEs). They are commonly known as prion diseases. However, since all amyloids could be considered prions (from those involved in cell-to-cell transmission to those responsible for real neuronal invasion), it is necessary to find an underlying cause of the different capacity to infect that each of the proteins prone to form amyloids has. As proposed here, both the intrinsic cytotoxicity and the number of nuclei of aggregation per cell could be key factors in this transmission capacity of each amyloid.
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Affiliation(s)
- Raimon Sabate
- Conformational Diseases Group; Department of Physical Chemistry; Faculty of Pharmacy; University of Barcelona (UB); Barcelona, Spain; Institut of Nanoscience and Nanotechnology of the University of Barcelona (IN2UB); Barcelona, Spain
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