51
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Dec R, Dzwolak W. A tale of two tails: Self-assembling properties of A- and B-chain parts of insulin's highly amyloidogenic H-fragment. Int J Biol Macromol 2021; 186:510-518. [PMID: 34271044 DOI: 10.1016/j.ijbiomac.2021.07.057] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/26/2021] [Accepted: 07/08/2021] [Indexed: 11/27/2022]
Abstract
Due to the spontaneous transition of native insulin into therapeutically inactive amyloid, prolonged storage decreases effectiveness of the hormone in treatment of diabetes. Various regions of the amino acid sequence have been implicated in insulin aggregation. Here, we focus on smaller fragments of the highly amyloidogenic H-peptide comprising disulfide-bonded N-terminal sections of insulin's A-chain (13 residues) and B-chain (11 residues). Aggregation patterns of N-terminal fragments of A-chain (ACC1-13, ACC1-11, ACC6-13, ACC6-11, all retaining Cys6A-Cys11A disulfide bond) and B-chain (B1-11(7A)) are examined at acidic and neutral pH. ACC1-11 is the smallest fragment found to be amyloidogenic at either pH; removal of the N-terminal GIVEQ section renders this fragment entirely non-amyloidogenic. The self-assembling properties of ACC1-11 contrast with aggregation-resistant behavior of B1-11(7A) and its disulfide-linked homodimer, (B1-11)2 aggregating only at neutral pH. Fibrillar ACC1-11 is similar to insulin amyloid in terms of morphology and infrared features. Secondary nucleation is likely to account for the detected shortening of insulin aggregation lag phase at neutral pH upon cross-seeding with pre-formed fibrils of ACC1-11 or (B1-11)2. An aggregation-enhancing effect of monomeric ACC1-11 on co-dissolved native insulin is also observed. Our findings are discussed in the context of mechanisms of insulin aggregation.
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Affiliation(s)
- Robert Dec
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 1 Pasteur Str., 02-093 Warsaw, Poland
| | - Wojciech Dzwolak
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 1 Pasteur Str., 02-093 Warsaw, Poland.
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52
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Bond MC, Vidakovic L, Singh PK, Drescher K, Nadell CD. Matrix-trapped viruses can prevent invasion of bacterial biofilms by colonizing cells. eLife 2021; 10:65355. [PMID: 34240700 PMCID: PMC8346279 DOI: 10.7554/elife.65355] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 07/08/2021] [Indexed: 12/19/2022] Open
Abstract
Bacteriophages can be trapped in the matrix of bacterial biofilms, such that the cells inside them are protected. It is not known whether these phages are still infectious and whether they pose a threat to newly arriving bacteria. Here, we address these questions using Escherichia coli and its lytic phage T7. Prior work has demonstrated that T7 phages are bound in the outermost curli polymer layers of the E. coli biofilm matrix. We show that these phages do remain viable and can kill colonizing cells that are T7-susceptible. If cells colonize a resident biofilm before phages do, we find that they can still be killed by phage exposure if it occurs soon thereafter. However, if colonizing cells are present on the biofilm long enough before phage exposure, they gain phage protection via envelopment within curli-producing clusters of the resident biofilm cells.
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Affiliation(s)
- Matthew C Bond
- Department of Biological Sciences, Dartmouth College, Hanover, United States
| | - Lucia Vidakovic
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Praveen K Singh
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Knut Drescher
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.,Department of Physics, Philipps University Marburg, Marburg, Germany.,Biozentrum, University of Basel, Basel, Switzerland
| | - Carey D Nadell
- Department of Biological Sciences, Dartmouth College, Hanover, United States
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53
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Matilla-Cuenca L, Toledo-Arana A, Valle J. Anti-Biofilm Molecules Targeting Functional Amyloids. Antibiotics (Basel) 2021; 10:antibiotics10070795. [PMID: 34210036 PMCID: PMC8300730 DOI: 10.3390/antibiotics10070795] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 12/18/2022] Open
Abstract
The choice of an effective therapeutic strategy in the treatment of biofilm-related infections is a significant issue. Amyloids, which have been historically related to human diseases, are now considered to be prevailing structural components of the biofilm matrix in a wide range of bacteria. This assumption creates the potential for an exciting research area, in which functional amyloids are considered to be attractive targets for drug development to dissemble biofilm structures. The present review describes the best-characterized bacterial functional amyloids and focuses on anti-biofilm agents that target intrinsic and facultative amyloids. This study provides a better understanding of the different modes of actions of the anti-amyloid molecules to inhibit biofilm formation. This information can be further exploited to improve the therapeutic strategies to combat biofilm-related infections.
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54
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Gómez-Pérez D, Chaudhry V, Kemen A, Kemen E. Amyloid Proteins in Plant-Associated Microbial Communities. Microb Physiol 2021; 31:88-98. [PMID: 34107493 DOI: 10.1159/000516014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 03/17/2021] [Indexed: 11/19/2022]
Abstract
Amyloids have proven to be a widespread phenomenon rather than an exception. Many proteins presenting the hallmarks of this characteristic beta sheet-rich folding have been described to date. Particularly common are functional amyloids that play an important role in the promotion of survival and pathogenicity in prokaryotes. Here, we describe important developments in amyloid protein research that relate to microbe-microbe and microbe-host interactions in the plant microbiome. Starting with biofilms, which are a broad strategy for bacterial persistence that is extremely important for plant colonization. Microbes rely on amyloid-based mechanisms to adhere and create a protective coating that shelters them from external stresses and promotes cooperation. Another strategy generally carried out by amyloids is the formation of hydrophobic surface layers. Known as hydrophobins, these proteins coat the aerial hyphae and spores of plant pathogenic fungi, as well as certain bacterial biofilms. They contribute to plant virulence through promoting dissemination and infectivity. Furthermore, antimicrobial activity is an interesting outcome of the amyloid structure that has potential application in medicine and agriculture. There are many known antimicrobial amyloids released by animals and plants; however, those produced by bacteria or fungi remain still largely unknown. Finally, we discuss amyloid proteins with a more indirect mode of action in their host interactions. These include virulence-promoting harpins, signaling transduction that functions through amyloid templating, and root nodule bacteria proteins that promote plant-microbe symbiosis. In summary, amyloids are an interesting paradigm for their many functional mechanisms linked to bacterial survival in plant-associated microbial communities.
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Affiliation(s)
| | | | - Ariane Kemen
- ZMBP/IMIT, University of Tübingen, Tübingen, Germany
| | - Eric Kemen
- ZMBP/IMIT, University of Tübingen, Tübingen, Germany
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55
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Hanke M, Yang Y, Ji Y, Grundmeier G, Keller A. Nanoscale Surface Topography Modulates hIAPP Aggregation Pathways at Solid-Liquid Interfaces. Int J Mol Sci 2021; 22:ijms22105142. [PMID: 34067963 PMCID: PMC8152259 DOI: 10.3390/ijms22105142] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/07/2021] [Accepted: 05/11/2021] [Indexed: 01/11/2023] Open
Abstract
The effects that solid–liquid interfaces exert on the aggregation of proteins and peptides are of high relevance for various fields of basic and applied research, ranging from molecular biology and biomedicine to nanotechnology. While the influence of surface chemistry has received a lot of attention in this context, the role of surface topography has mostly been neglected so far. In this work, therefore, we investigate the aggregation of the type 2 diabetes-associated peptide hormone hIAPP in contact with flat and nanopatterned silicon oxide surfaces. The nanopatterned surfaces are produced by ion beam irradiation, resulting in well-defined anisotropic ripple patterns with heights and periodicities of about 1.5 and 30 nm, respectively. Using time-lapse atomic force microscopy, the morphology of the hIAPP aggregates is characterized quantitatively. Aggregation results in both amorphous aggregates and amyloid fibrils, with the presence of the nanopatterns leading to retarded fibrillization and stronger amorphous aggregation. This is attributed to structural differences in the amorphous aggregates formed at the nanopatterned surface, which result in a lower propensity for nucleating amyloid fibrillization. Our results demonstrate that nanoscale surface topography may modulate peptide and protein aggregation pathways in complex and intricate ways.
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56
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Molina-Santiago C, de Vicente A, Romero D. Bacterial extracellular matrix as a natural source of biotechnologically multivalent materials. Comput Struct Biotechnol J 2021; 19:2796-2805. [PMID: 34093994 PMCID: PMC8138678 DOI: 10.1016/j.csbj.2021.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/29/2021] [Accepted: 05/02/2021] [Indexed: 12/15/2022] Open
Abstract
The extracellular matrix (ECM) is an intricate megastructure made by bacterial cells to form architecturally complex biostructures called biofilms. Protection of cells, modulation of cell-to-cell signalling, cell differentiation and environmental sensing are functions of the ECM that reflect its diverse chemical composition. Proteins, polysaccharides and eDNA have specific functionalities while cooperatively interacting to sustain the architecture and biological relevance of the ECM. The accumulated evidence on the chemical heterogeneity and specific functionalities of ECM components has attracted attention because of their potential biotechnological applications, from agriculture to the water and food industries. This review compiles information on the most relevant bacterial ECM components, the biophysical and chemical features responsible for their biological roles, and their potential to be further translated into biotechnological applications.
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Affiliation(s)
- Carlos Molina-Santiago
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Universidad de Málaga, Bulevar Louis Pasteur 31 (Campus Universitario de teatinos), 29071 Málaga, Spain
| | - Antonio de Vicente
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Universidad de Málaga, Bulevar Louis Pasteur 31 (Campus Universitario de teatinos), 29071 Málaga, Spain
| | - Diego Romero
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Universidad de Málaga, Bulevar Louis Pasteur 31 (Campus Universitario de teatinos), 29071 Málaga, Spain
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57
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Hayward S, Milner-White EJ. Determination of amino acids that favour the α L region using Ramachandran propensity plots. Implications for α-sheet as the possible amyloid intermediate. J Struct Biol 2021; 213:107738. [PMID: 33838226 DOI: 10.1016/j.jsb.2021.107738] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 04/01/2021] [Accepted: 04/04/2021] [Indexed: 11/28/2022]
Abstract
In amyloid diseases an insoluble amyloid fibril forms via a soluble oligomeric intermediate. It is this intermediate that mediates toxicity and it has been suggested, somewhat controversially, that it has the α-sheet structure. Nests and α-strands are similar peptide motifs in that alternate residues lie in the αR and γL regions of the Ramachandran plot for nests, or αR and αL regions for α-strands. In nests a concavity is formed by the main chain NH atoms whereas in α-strands the main chain is almost straight. Using "Ramachandran propensity plots" to focus on the αL/γL region, it is shown that glycine favours γL (82% of amino acids are glycine), but disfavours αL (3% are glycine). Most charged and polar amino acids favour αL with asparagine having by far the highest propensity. Thus, glycine favours nests but, contrary to common expectation, should not favour α-sheet. By contrast most charged or polar amino acids should favour α-sheet by their propensity for the αL conformation, which is more discriminating amongst amino acids than the αR conformation. Thus, these results suggest the composition of sequences that favour α-sheet formation and point towards effective prediction of α-sheet from sequence.
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Affiliation(s)
- Steven Hayward
- Computational Biology Laboratory, School of Computing Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
| | - E James Milner-White
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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58
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Azeredo J, García P, Drulis-Kawa Z. Targeting biofilms using phages and their enzymes. Curr Opin Biotechnol 2021; 68:251-261. [PMID: 33714050 DOI: 10.1016/j.copbio.2021.02.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/02/2021] [Accepted: 02/10/2021] [Indexed: 02/08/2023]
Abstract
The complex biofilm architecture composed of extracellular polymeric structures (EPS) provides a protective shield to physiologically diverse bacterial cells immersed in its structure. The evolutionary interplay between bacteria and their viruses (phages) forced the latter ones to develop specific strategies to overcome the biofilm defensive barriers and kill sessile cells. Phages are equipped with a wide panel of enzyme-degrading EPS macromolecules which together are powerful weapons to combat biofilms. Antibiofilm performance can be achieved by combining phages or phage-borne enzymes with other antimicrobials such as antibiotics. Nevertheless, a variety of enzymes encoded in phage genomes still need to be explored. To advance in biofilm control strategies we must deepen the understanding of the biofilm biology itself, as well as discover and better exploit the unlimited antibacterial potential of phages.
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Affiliation(s)
- Joana Azeredo
- Centro de Engenharia Biológica, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| | - Pilar García
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares sn. 33300, Villaviciosa, Asturias, Spain.
| | - Zuzanna Drulis-Kawa
- Department of Pathogen Biology and Immunology, Institute of Genetics and Microbiology, University of Wroclaw, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland.
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59
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Siniukova VA, Sopova JV, Galkina SA, Galkin AP. Search for functional amyloid structures in chicken and fruit fly female reproductive cells. Prion 2020; 14:278-282. [PMID: 33300441 PMCID: PMC7734138 DOI: 10.1080/19336896.2020.1859439] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We conducted a cytological search for amyloid structures in female reproductive cells of Gallus gallus domesticus and Drosophila melanogaster. We have shown that the amyloid-specific dye, Thioflavin S, but not Congo red, stains some cytoplasmic and even nuclear structures in chicken ovaries. In fruit fly eggs both Thioflavin S and Congo red specifically stain eggshell structures such as micropyle, dorsal appendages and pillars. Moreover, these structures, when stained with Congo red, demonstrate birefringence in polarized light, which is a characteristic feature of all classical amyloids. Our data show that female reproductive cells during evolution began to use amyloid fibrils to form various functional structures necessary for development under certain environmental conditions.
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Affiliation(s)
- V A Siniukova
- St. Petersburg Branch, Vavilov Institute of General Genetics , St. Petersburg, Russian Federation
| | - J V Sopova
- St. Petersburg Branch, Vavilov Institute of General Genetics , St. Petersburg, Russian Federation.,Laboratory of Amyloid Biology, St. Petersburg State University , St. Petersburg, Russian Federation
| | - S A Galkina
- Department of Genetics and Biotechnology, St. Petersburg State University , St. Petersburg, Russian Federation
| | - A P Galkin
- St. Petersburg Branch, Vavilov Institute of General Genetics , St. Petersburg, Russian Federation.,Department of Genetics and Biotechnology, St. Petersburg State University , St. Petersburg, Russian Federation
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60
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Burra G, Maina MB, Serpell LC, Thakur AK. Nucleation-dependent Aggregation Kinetics of Yeast Sup35 Fragment GNNQQNY. J Mol Biol 2020; 433:166732. [PMID: 33279578 DOI: 10.1016/j.jmb.2020.166732] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 11/25/2020] [Accepted: 11/30/2020] [Indexed: 10/22/2022]
Abstract
An N-terminal hepta-peptide sequence of yeast prion protein Sup35 with the sequence GNNQQNY is widely used as a model system for amyloid fibril formation. In this study, we used a reproducible solubilisation protocol that allows the generation of a homogenous monomeric solution of GNNQQNY to uncover the molecular details of its self-assembly mechanism. The aggregation kinetics data show that the GNNQQNY sequence follows nucleation-dependent aggregation kinetics with a critical nucleus of size ~7 monomers and that the efficiency of nucleation were found to be inversely related to the reaction temperature. The nucleus reduces the thermodynamic energy barrier by acting as a template for further self-assembly and results in highly ordered amyloid fibrils. The fibers grown at different temperatures showed similar Thioflavin T fluorescence, Congo-red binding and β-sheet rich structures displaying a characteristic cross-β diffraction pattern. These aggregates also share morphological and structural identity with those reported earlier. The mature GNNQQNY fibers did not exert significant oxidative stress or cytotoxicity upon incubating with differentiated SHSY5Y cells. To our knowledge, this is the first study to experimentally validate previous nucleus size predictions based on theoretical and molecular dynamics simulations. These findings provide the basis for understanding the kinetics and thermodynamics of amyloid nucleation and elongation of amyloidogenic proteins/peptides associated with many systemic and neurodegenerative diseases.
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Affiliation(s)
- Gunasekhar Burra
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, India; Sussex Neuroscience, School of Life Sciences, University of Sussex, UK.
| | - Mahmoud B Maina
- Sussex Neuroscience, School of Life Sciences, University of Sussex, UK; College of Medical Sciences, Yobe State University, Nigeria
| | - Louise C Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, UK
| | - Ashwani K Thakur
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, India.
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61
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Expression of an Extracellular Protein (SMU.63) Is Regulated by SprV in Streptococcus mutans. Appl Environ Microbiol 2020; 86:AEM.01647-20. [PMID: 32978138 DOI: 10.1128/aem.01647-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/20/2020] [Indexed: 12/19/2022] Open
Abstract
In Streptococcus mutans, SprV (SMU.2137) is a pleiotropic regulator that differentially regulates genes related to competence, mutacin production, biofilm formation, and the stress tolerance response, along with some other pathways. In this study, we established a link between SprV and an ∼67-kDa protein in the culture supernatant of strain UA159 that was later confirmed as SMU.63 by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. We discovered that SprV downregulates the transcription and translation of SMU.63. We found that the seven amino acids from the C-terminal region of SprV were also crucial for the expression of SMU.63. Deletion of smu.63 led to increased sucrose-independent biofilm formation and competence. The sprV deletion also increased biofilm formation although this could be partially attributed to the downregulation of smu.63 In an smu.63 sprV double mutant, a synergistic effect was observed in biofilm formation in contrast to effects on competence development. We found that low or excess magnesium ion repressed sprV transcription that, in turn, affected the expression of smu.63 As expected, a magnesium ion-dependent effect of competence and biofilm formation was observed in the UA159 strain. We also replicated the results of SMU.63 expression and competence in S. mutans GS5 that encodes both SprV and SMU.63 homologs and found that the GS5 strain behaves similarly to the UA159 strain, indicating that SprV's effect is strain independent.IMPORTANCE We previously identified a pleiotropic regulator, SprV, in Streptococcus mutans This regulator appears to be highly conserved among streptococci. Here, we showed that SprV regulates the expression of a secreted protein encoded by SMU.63 in S. mutans SMU.63 has been known to impact biofilm formation and genetic competence, two important characteristics that help in colonization of the organism. SMU.63 is also unique since it is known to form amyloid fiber. We found that SprV regulates the expression of SMU.63 at both the transcriptional and translational levels. We also found that the expression of SprV is regulated by magnesium ion concentration. Interestingly, both low and high magnesium ion concentrations affected biofilm formation and genetic competence. Since SMU.63 is also highly conserved among streptococci, we hypothesized that SprV will have a similar effect on its expression.
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62
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Dec R, Guza M, Dzwolak W. Reduction of a disulfide-constrained oligo-glutamate peptide triggers self-assembly of β 2-type amyloid fibrils with the chiroptical properties determined by supramolecular chirality. Int J Biol Macromol 2020; 162:866-872. [PMID: 32593758 DOI: 10.1016/j.ijbiomac.2020.06.221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 06/15/2020] [Accepted: 06/23/2020] [Indexed: 11/27/2022]
Abstract
Disulfide bonds prevent aggregation of globular proteins by stabilizing the native state. However, a disulfide bond within a disordered state may accelerate amyloidogenic nucleation by navigating fluctuating polypeptide chains towards an orderly assembly of β-sheets. Here, the self-assembly behavior of Glu-Cys-(Glu)4-Cys-Glu peptide (E6C2), in which an intrachain disulfide bond is engineered into an amyloidogenic homopolypeptide motif, is investigated. To this end, the Thioflavin T (ThT) fluorescence kinetic assay is combined with infrared spectroscopy, circular dichroism (CD), atomic force microscopy (AFM) and Raman scattering measurements. Regardless of whether the disulfide bond is intact or reduced, E6C2 monomers remain disordered within a broad range of pH. On the other hand, only reduced E6C2 self-assembles into amyloid fibrils with the unique infrared traits indicative of three-center hydrogen bonds involving main-chain carbonyl as a bifurcating acceptor and main-chain NH and side-chain -COOH groups as hydrogen donors: the bonding pattern observed in so-called β2-fibrils. AFM analysis of β2-E6C2 reveals tightly packed rectangular superstructures whose presence coincides with strong chiroptical properties. Our findings suggest that formation of chiral amyloid superstructures may be a generic process accessible to various substrates, and that the fully extended conformation of a poly-Glu chain is a condition sine qua non for self-assembly of β2-fibrils.
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Affiliation(s)
- Robert Dec
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 1 Pasteur Str., 02-093 Warsaw, Poland
| | - Marcin Guza
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 1 Pasteur Str., 02-093 Warsaw, Poland
| | - Wojciech Dzwolak
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 1 Pasteur Str., 02-093 Warsaw, Poland.
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63
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Dyrka W, Coustou V, Daskalov A, Lends A, Bardin T, Berbon M, Kauffmann B, Blancard C, Salin B, Loquet A, Saupe SJ. Identification of NLR-associated Amyloid Signaling Motifs in Bacterial Genomes. J Mol Biol 2020; 432:6005-6027. [PMID: 33058872 DOI: 10.1016/j.jmb.2020.10.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 10/05/2020] [Accepted: 10/05/2020] [Indexed: 02/06/2023]
Abstract
In filamentous fungi, amyloid signaling sequences allow Nod-like receptors (NLRs) to activate downstream cell-death inducing proteins with HeLo and HeLo-like (HELL) domains and amyloid RHIM and RHIM-related motifs control immune defense pathways in mammals and flies. Herein, we show bioinformatically that analogous amyloid signaling motifs exist in bacteria. These short motifs are found at the N terminus of NLRs and at the C terminus of proteins with a domain we term BELL. The corresponding NLR and BELL proteins are encoded by adjacent genes. We identify 10 families of such bacterial amyloid signaling sequences (BASS), one of which (BASS3) is homologous to RHIM and a fungal amyloid motif termed PP. BASS motifs occur nearly exclusively in bacteria forming multicellular structures (mainly in Actinobacteria and Cyanobacteria). We analyze experimentally a subset of seven of these motifs (from the most common BASS1 family and the RHIM-related BASS3 family) and find that these sequences form fibrils in vitro. Using a fungal in vivo model, we show that all tested BASS-motifs form prions and that the NLR-side motifs seed prion-formation of the corresponding BELL-side motif. We find that BASS3 motifs show partial prion cross-seeding with mammalian RHIM and fungal PP-motifs and that proline mutations on key positions of the BASS3 core motif, conserved in RHIM and PP-motifs, abolish prion formation. This work expands the paradigm of prion amyloid signaling to multicellular prokaryotes and suggests a long-term evolutionary conservation of these motifs from bacteria, to fungi and animals.
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Affiliation(s)
- Witold Dyrka
- Politechnika Wrocławska, Wydział Podstawowych Problemów Techniki, Katedra Inżynierii Biomedycznej, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Virginie Coustou
- Non-self Recognition in Fungi, Institut de Biochimie et de Génétique Cellulaire, UMR 5095 CNRS, Université de Bordeaux, 1 Rue Camille Saint Saëns, 33077 Bordeaux CEDEX, France
| | - Asen Daskalov
- Institute of Chemistry & Biology of Membranes & Nanoobjects, UMR5248 CBMN, IECB, CNRS, Université de Bordeaux, Allee Geoffroy Saint-Hilaire, 33607 Pessac, France
| | - Alons Lends
- Institute of Chemistry & Biology of Membranes & Nanoobjects, UMR5248 CBMN, IECB, CNRS, Université de Bordeaux, Allee Geoffroy Saint-Hilaire, 33607 Pessac, France
| | - Thierry Bardin
- Non-self Recognition in Fungi, Institut de Biochimie et de Génétique Cellulaire, UMR 5095 CNRS, Université de Bordeaux, 1 Rue Camille Saint Saëns, 33077 Bordeaux CEDEX, France
| | - Mélanie Berbon
- Institut de Biochimie et de Génétique Cellulaire, UMR 5095 CNRS, Université de Bordeaux, 1 Rue Camille Saint Saëns, 33077 Bordeaux CEDEX, France
| | - Brice Kauffmann
- IECB, UMS 3033, US 001, CNRS, Université de Bordeaux, 2 Rue Robert Escarpit, 33607 Pessac, France
| | - Corinne Blancard
- Institut de Biochimie et de Génétique Cellulaire, UMR 5095 CNRS, Université de Bordeaux, 1 Rue Camille Saint Saëns, 33077 Bordeaux CEDEX, France
| | - Bénédicte Salin
- Institut de Biochimie et de Génétique Cellulaire, UMR 5095 CNRS, Université de Bordeaux, 1 Rue Camille Saint Saëns, 33077 Bordeaux CEDEX, France
| | - Antoine Loquet
- Institute of Chemistry & Biology of Membranes & Nanoobjects, UMR5248 CBMN, IECB, CNRS, Université de Bordeaux, Allee Geoffroy Saint-Hilaire, 33607 Pessac, France
| | - Sven J Saupe
- Non-self Recognition in Fungi, Institut de Biochimie et de Génétique Cellulaire, UMR 5095 CNRS, Université de Bordeaux, 1 Rue Camille Saint Saëns, 33077 Bordeaux CEDEX, France.
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Ali AM, Kunugi H. Royal Jelly as an Intelligent Anti-Aging Agent-A Focus on Cognitive Aging and Alzheimer's Disease: A Review. Antioxidants (Basel) 2020; 9:E937. [PMID: 33003559 PMCID: PMC7601550 DOI: 10.3390/antiox9100937] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 09/24/2020] [Accepted: 09/24/2020] [Indexed: 02/08/2023] Open
Abstract
The astronomical increase of the world's aged population is associated with the increased prevalence of neurodegenerative diseases, heightened disability, and extremely high costs of care. Alzheimer's Disease (AD) is a widespread, age-related, multifactorial neurodegenerative disease that has enormous social and financial drawbacks worldwide. The unsatisfactory outcomes of available AD pharmacotherapy necessitate the search for alternative natural resources that can target various the underlying mechanisms of AD pathology and reduce disease occurrence and/or progression. Royal jelly (RJ) is the main food of bee queens; it contributes to their fertility, long lifespan, and memory performance. It represents a potent nutraceutical with various pharmacological properties, and has been used in a number of preclinical studies to target AD and age-related cognitive deterioration. To understand the mechanisms through which RJ affects cognitive performance both in natural aging and AD, we reviewed the literature, elaborating on the metabolic, molecular, and cellular mechanisms that mediate its anti-AD effects. Preclinical findings revealed that RJ acts as a multidomain cognitive enhancer that can restore cognitive performance in aged and AD models. It promotes brain cell survival and function by targeting multiple adversities in the neuronal microenvironment such as inflammation, oxidative stress, mitochondrial alterations, impaired proteostasis, amyloid-β toxicity, Ca excitotoxicity, and bioenergetic challenges. Human trials using RJ in AD are limited in quantity and quality. Here, the limitations of RJ-based treatment strategies are discussed, and directions for future studies examining the effect of RJ in cognitively impaired subjects are noted.
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Affiliation(s)
- Amira Mohammed Ali
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo 187-0031, Japan;
- Department of Psychiatric Nursing and Mental Health, Faculty of Nursing, Alexandria University, Alexandria 21527, Egypt
| | - Hiroshi Kunugi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo 187-0031, Japan;
- Department of Psychiatry, Teikyo University School of Medicine, Tokyo 173-8605, Japan
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65
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Pruteanu M, Hernández Lobato JI, Stach T, Hengge R. Common plant flavonoids prevent the assembly of amyloid curli fibres and can interfere with bacterial biofilm formation. Environ Microbiol 2020; 22:5280-5299. [PMID: 32869465 DOI: 10.1111/1462-2920.15216] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/25/2020] [Accepted: 08/27/2020] [Indexed: 01/01/2023]
Abstract
Like all macroorganisms, plants have to control bacterial biofilm formation on their surfaces. On the other hand, biofilms are highly tolerant against antimicrobial agents and other stresses. Consequently, biofilms are also involved in human chronic infectious diseases, which generates a strong demand for anti-biofilm agents. Therefore, we systematically explored major plant flavonoids as putative anti-biofilm agents using different types of biofilms produced by Gram-negative and Gram-positive bacteria. In Escherichia coli macrocolony biofilms, the flavone luteolin and the flavonols myricetin, morin and quercetin were found to strongly reduce the extracellular matrix. These agents directly inhibit the assembly of amyloid curli fibres by driving CsgA subunits into an off-pathway leading to SDS-insoluble oligomers. In addition, they can interfere with cellulose production by still unknown mechanisms. Submerged biofilm formation, however, is hardly affected. Moreover, the same flavonoids tend to stimulate macrocolony and submerged biofilm formation by Pseudomonas aeruginosa. For Bacillus subtilis, the flavonone naringenin and the chalcone phloretin were found to inhibit growth. Thus, plant flavonoids are not general anti-biofilm compounds but show species-specific effects. However, based on their strong and direct anti-amyloidogenic activities, distinct plant flavonoids may provide an attractive strategy to specifically combat amyloid-based biofilms of some relevant pathogens.
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Affiliation(s)
- Mihaela Pruteanu
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
| | | | - Thomas Stach
- Institut für Biologie/Zoologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
| | - Regine Hengge
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
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66
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Aubrey LD, Blakeman BJF, Lutter L, Serpell CJ, Tuite MF, Serpell LC, Xue WF. Quantification of amyloid fibril polymorphism by nano-morphometry reveals the individuality of filament assembly. Commun Chem 2020; 3:125. [PMID: 36703355 PMCID: PMC9814634 DOI: 10.1038/s42004-020-00372-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 08/12/2020] [Indexed: 01/29/2023] Open
Abstract
Amyloid fibrils are highly polymorphic structures formed by many different proteins. They provide biological function but also abnormally accumulate in numerous human diseases. The physicochemical principles of amyloid polymorphism are not understood due to lack of structural insights at the single-fibril level. To identify and classify different fibril polymorphs and to quantify the level of heterogeneity is essential to decipher the precise links between amyloid structures and their functional and disease associated properties such as toxicity, strains, propagation and spreading. Employing gentle, force-distance curve-based AFM, we produce detailed images, from which the 3D reconstruction of individual filaments in heterogeneous amyloid samples is achieved. Distinctive fibril polymorphs are then classified by hierarchical clustering, and sample heterogeneity is objectively quantified. These data demonstrate the polymorphic nature of fibril populations, provide important information regarding the energy landscape of amyloid self-assembly, and offer quantitative insights into the structural basis of polymorphism in amyloid populations.
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Affiliation(s)
- Liam D. Aubrey
- grid.9759.20000 0001 2232 2818Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, CT2 7NJ UK
| | - Ben J. F. Blakeman
- grid.9759.20000 0001 2232 2818Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, CT2 7NJ UK
| | - Liisa Lutter
- grid.9759.20000 0001 2232 2818Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, CT2 7NJ UK
| | - Christopher J. Serpell
- grid.9759.20000 0001 2232 2818School of Physical Sciences, University of Kent, Canterbury, CT2 7NH UK
| | - Mick F. Tuite
- grid.9759.20000 0001 2232 2818Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, CT2 7NJ UK
| | - Louise C. Serpell
- grid.12082.390000 0004 1936 7590Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG UK
| | - Wei-Feng Xue
- grid.9759.20000 0001 2232 2818Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, CT2 7NJ UK
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67
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Abstract
The formation of dense, linear arrays (fibrils) by biomolecules is the hallmark of a number of degenerative diseases, such as Alzheimer's and type-2 diabetes. Protein fibrils have also attracted interest as building blocks for new materials. It has long been recognized that surfaces can affect the fibrillation process. Recent work on the model fibril forming protein human islet amyloid polypeptide (hIAPP) has shown that while the protein concentration is highest at hydrophobic surfaces, the rate of fibril formation is lower than on other surfaces. To understand this, replica exchange molecular dynamics simulations were used to investigate the conformations that hIAPP adopts on surfaces of different hydrophobicities. The hydrophobic surface stabilizes α-helical structures which are significantly different to those found on the hydrophilic surface and in bulk solution. There is also a greatly reduced conformational ensemble on the hydrophobic surface due to long-lived contacts between hydrophobic residues on the protein and the surface. This new microscopic information will help us determine the mechanism of the enhancement of fibril formation on surfaces and provides new insight into the effect of nanointerfaces and protein conformation.
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68
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Earl C, Arnaouteli S, Bamford NC, Porter M, Sukhodub T, MacPhee CE, Stanley-Wall NR. The majority of the matrix protein TapA is dispensable for Bacillus subtilis colony biofilm architecture. Mol Microbiol 2020; 114:920-933. [PMID: 32491277 DOI: 10.1111/mmi.14559] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 01/08/2023]
Abstract
Biofilm formation is a co-operative behaviour, where microbial cells become embedded in an extracellular matrix. This biomolecular matrix helps manifest the beneficial or detrimental outcome mediated by the collective of cells. Bacillus subtilis is an important bacterium for understanding the principles of biofilm formation. The protein components of the B. subtilis matrix include the secreted proteins BslA, which forms a hydrophobic coat over the biofilm, and TasA, which forms protease-resistant fibres needed for structuring. TapA is a secreted protein also needed for biofilm formation and helps in vivo TasA-fibre formation but is dispensable for in vitro TasA-fibre assembly. We show that TapA is subjected to proteolytic cleavage in the colony biofilm and that only the first 57 amino acids of the 253-amino acid protein are required for colony biofilm architecture. Through the construction of a strain which lacks all eight extracellular proteases, we show that proteolytic cleavage by these enzymes is not a prerequisite for TapA function. It remains unknown why TapA is synthesised at 253 amino acids when the first 57 are sufficient for colony biofilm structuring; the findings do not exclude the core conserved region of TapA having a second role beyond structuring the B. subtilis colony biofilm.
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Affiliation(s)
- Chris Earl
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Sofia Arnaouteli
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Natalie C Bamford
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Michael Porter
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Tetyana Sukhodub
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Cait E MacPhee
- James Clerk Maxwell Building, School of Physics, University of Edinburgh, Edinburgh, UK
| | - Nicola R Stanley-Wall
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
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69
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The zoonotic pathogen Leptospira interrogans mitigates environmental stress through cyclic-di-GMP-controlled biofilm production. NPJ Biofilms Microbiomes 2020; 6:24. [PMID: 32532998 PMCID: PMC7293261 DOI: 10.1038/s41522-020-0134-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/14/2020] [Indexed: 12/24/2022] Open
Abstract
The zoonotic bacterium Leptospira interrogans is the aetiological agent of leptospirosis, a re-emerging infectious disease that is a growing public health concern. Most human cases of leptospirosis result from environmental infection. Biofilm formation and its contribution to the persistence of virulent leptospires in the environment or in the host have scarcely been addressed. Here, we examined spatial and time-domain changes in biofilm production by L. interrogans. Our observations showed that biofilm formation in L. interrogans is a highly dynamic process and leads to a polarized architecture. We notably found that the biofilm matrix is composed of extracellular DNA, which enhances the biofilm's cohesiveness. By studying L. interrogans mutants with defective diguanylate cyclase and phosphodiesterase genes, we show that biofilm production is regulated by intracellular levels of bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) and underpins the bacterium's ability to withstand a wide variety of simulated environmental stresses. Our present results show how the c-di-GMP pathway regulates biofilm formation by L. interrogans, provide insights into the environmental persistence of L. interrogans and, more generally, highlight leptospirosis as an environment-borne threat to human health.
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70
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Functional amyloids of eukaryotes: criteria, classification, and biological significance. Curr Genet 2020; 66:849-866. [DOI: 10.1007/s00294-020-01079-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/16/2020] [Accepted: 04/20/2020] [Indexed: 11/26/2022]
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71
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Karygianni L, Ren Z, Koo H, Thurnheer T. Biofilm Matrixome: Extracellular Components in Structured Microbial Communities. Trends Microbiol 2020; 28:668-681. [PMID: 32663461 DOI: 10.1016/j.tim.2020.03.016] [Citation(s) in RCA: 516] [Impact Index Per Article: 129.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 03/16/2020] [Accepted: 03/25/2020] [Indexed: 02/04/2023]
Abstract
Biofilms consist of microbial communities embedded in a 3D extracellular matrix. The matrix is composed of a complex array of extracellular polymeric substances (EPS) that contribute to the unique attributes of biofilm lifestyle and virulence. This ensemble of chemically and functionally diverse biomolecules is termed the 'matrixome'. The composition and mechanisms of EPS matrix formation, and its role in biofilm biology, function, and microenvironment are being revealed. This perspective article highlights recent advances about the multifaceted role of the 'matrixome' in the development, physical-chemical properties, and virulence of biofilms. We emphasize that targeting biofilm-specific conditions such as the matrixome could lead to precise and effective antibiofilm approaches. We also discuss the limited knowledge in the context of polymicrobial biofilms, and the need for more in-depth analyses of the EPS matrix in mixed communities that are associated with many human infectious diseases.
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Affiliation(s)
- L Karygianni
- Clinic of Conservative and Preventive Dentistry, Center of Dental Medicine University of Zurich, Zurich, Switzerland
| | - Z Ren
- Department of Orthodontics, Divisions of Pediatric Dentistry and Community of Oral Health, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA
| | - H Koo
- Department of Orthodontics, Divisions of Pediatric Dentistry and Community of Oral Health, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA; Center for Innovation and Precision Dentistry, University of Pennsylvania School of Dental Medicine, School of Engineering and Applied Sciences, Philadelphia, PA, USA
| | - T Thurnheer
- Clinic of Conservative and Preventive Dentistry, Center of Dental Medicine University of Zurich, Zurich, Switzerland.
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72
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Barran-Berdon AL, Ocampo S, Haider M, Morales-Aparicio J, Ottenberg G, Kendall A, Yarmola E, Mishra S, Long JR, Hagen SJ, Stubbs G, Brady LJ. Enhanced purification coupled with biophysical analyses shows cross-β structure as a core building block for Streptococcus mutans functional amyloids. Sci Rep 2020; 10:5138. [PMID: 32198417 PMCID: PMC7083922 DOI: 10.1038/s41598-020-62115-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 02/14/2020] [Indexed: 11/10/2022] Open
Abstract
Streptococcus mutans is an etiologic agent of human dental caries that forms dental plaque biofilms containing functional amyloids. Three amyloidogenic proteins, P1, WapA, and Smu_63c were previously identified. C123 and AgA are naturally occurring amyloid-forming fragments of P1 and WapA, respectively. We determined that four amyloidophilic dyes, ThT, CDy11, BD-oligo, and MK-H4, differentiate C123, AgA, and Smu_63c amyloid from monomers, but non-specific binding to bacterial cells in the absence of amyloid precludes their utility for identifying amyloid in biofilms. Congo red-induced birefringence is a more specific indicator of amyloid formation and differentiates biofilms formed by wild-type S. mutans from a triple ΔP1/WapA/Smu_63c mutant with reduced biofilm forming capabilities. Amyloid accumulation is a late event, appearing in older S. mutans biofilms after 60 hours of growth. Amyloid derived from pure preparations of all three proteins is visualized by electron microscopy as mat-like structures. Typical amyloid fibers become evident following protease digestion to eliminate non-specific aggregates and monomers. Amyloid mats, similar in appearance to those reported in S. mutans biofilm extracellular matrices, are reconstituted by co-incubation of monomers and amyloid fibers. X-ray fiber diffraction of amyloid mats and fibers from all three proteins demonstrate patterns reflective of a cross-β amyloid structure.
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Affiliation(s)
- Ana L Barran-Berdon
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Sebastian Ocampo
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Momin Haider
- Department of Physics, University of Florida, Gainesville, Florida, USA
| | | | - Gregory Ottenberg
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Amy Kendall
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Elena Yarmola
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Surabhi Mishra
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Joanna R Long
- Department of Biochemistry, University of Florida, Gainesville, Florida, USA
| | - Stephen J Hagen
- Department of Physics, University of Florida, Gainesville, Florida, USA
| | - Gerald Stubbs
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - L Jeannine Brady
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA.
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73
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Lotti T, Carretti E, Berti D, Montis C, Del Buffa S, Lubello C, Feng C, Malpei F. Hydrogels formed by anammox extracellular polymeric substances: structural and mechanical insights. Sci Rep 2019; 9:11633. [PMID: 31406144 PMCID: PMC6690907 DOI: 10.1038/s41598-019-47987-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 07/18/2019] [Indexed: 11/30/2022] Open
Abstract
The recovery of biopolymers from the waste sludge produced in wastewater treatments and their application in other industrial sectors, would substantially increase the environmental and economical sustainability of the process, promoting the development of a circular economy. In this study, extracellular polymeric substances (EPS) extracted from anammox granular waste sludge, were investigated and characterized. Rheological and differential scanning calorimetry measurements on EPS aqueous dispersions indicate the formation of an extended 3-D network above a threshold concentration, with a clear dependence of the mechanical and water retention properties on EPS content. The structural characterization, performed with transmission electron microscopy and small angle X-ray scattering, reveals the presence of functional amyloids as putative structural units, observed for the first time in an EPS-based hydrogel. As a proof of concept of the applicative potential, we explored the water and grease resistance provided to paper by an EPS coating. These results shed light on the structural details of EPS-based hydrogels, and pave the way for the possible use of EPS-based materials as a cheap, eco-friendly alternative to commonly adopted paper coatings, in line with a circular economy pattern for wastewater treatment.
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Affiliation(s)
- Tommaso Lotti
- Department of Civil and Environmental Engineering, Polytechnic University of Milan, Via Golgi 39, 20133, Milan, Italy. .,Civil and Environmental Engineering Department, University of Florence, Via di Santa Marta 3, 50139, Florence, Italy.
| | - Emiliano Carretti
- Department of Chemistry "Ugo Schiff" & CSGI Consortium, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino (FI), Florence, Italy
| | - Debora Berti
- Department of Chemistry "Ugo Schiff" & CSGI Consortium, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino (FI), Florence, Italy
| | - Costanza Montis
- Department of Chemistry "Ugo Schiff" & CSGI Consortium, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino (FI), Florence, Italy
| | - Stefano Del Buffa
- Department of Chemistry "Ugo Schiff" & CSGI Consortium, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino (FI), Florence, Italy.,Université de Strasbourg, CNRS, ISIS, 8 allée Gaspard Monge, 67000, Strasbourg, France
| | - Claudio Lubello
- Civil and Environmental Engineering Department, University of Florence, Via di Santa Marta 3, 50139, Florence, Italy
| | - Cuijie Feng
- Department of Civil and Environmental Engineering, Polytechnic University of Milan, Via Golgi 39, 20133, Milan, Italy
| | - Francesca Malpei
- Department of Civil and Environmental Engineering, Polytechnic University of Milan, Via Golgi 39, 20133, Milan, Italy
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74
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Hengge R. Targeting Bacterial Biofilms by the Green Tea Polyphenol EGCG. Molecules 2019; 24:molecules24132403. [PMID: 31261858 PMCID: PMC6650844 DOI: 10.3390/molecules24132403] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/24/2019] [Accepted: 06/25/2019] [Indexed: 12/20/2022] Open
Abstract
Bacterial biofilms are multicellular aggregates in which cells are embedded in an extracellular matrix of self-produced biopolymers. Being refractory to antibiotic treatment and host immune systems, biofilms are involved in most chronic infections, and anti-biofilm agents are being searched for urgently. Epigallocatechin-3-gallate (EGCG) was recently shown to act against biofilms by strongly interfering with the assembly of amyloid fibres and the production of phosphoethanolamin-modified cellulose fibrils. Mechanistically, this includes a direct inhibition of the fibre assembly, but also triggers a cell envelope stress response that down-regulates the synthesis of these widely occurring biofilm matrix polymers. Based on its anti-amyloidogenic properties, EGCG seems useful against biofilms involved in cariogenesis or chronic wound infection. However, EGCG seems inefficient against or may even sometimes promote biofilms which rely on other types of matrix polymers, suggesting that searching for 'magic bullet' anti-biofilm agents is an unrealistic goal. Combining molecular and ecophysiological aspects in this review also illustrates why plants control the formation of biofilms on their surfaces by producing anti-amyloidogenic compounds such as EGCG. These agents are not only helpful in combating certain biofilms in chronic infections but even seem effective against the toxic amyloids associated with neuropathological diseases.
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Affiliation(s)
- Regine Hengge
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, 10155 Berlin, Germany.
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75
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Repertoire of the Bacillus thuringiensis Virulence Factors Unrelated to Major Classes of Protein Toxins and Its Role in Specificity of Host-Pathogen Interactions. Toxins (Basel) 2019; 11:toxins11060347. [PMID: 31212976 PMCID: PMC6628457 DOI: 10.3390/toxins11060347] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 05/21/2019] [Accepted: 06/10/2019] [Indexed: 12/28/2022] Open
Abstract
Bacillus thuringiensis (Bt) is a Gram-positive soil bacteria that infects invertebrates, predominantly of Arthropoda phylum. Due to its immense host range Bt has become a leading producer of biopesticides applied both in biotechnology and agriculture. Cytotoxic effect of Bt, as well as its host specificity, are commonly attributed either to proteinaceous crystal parasporal toxins (Cry and Cyt) produced by bacteria in a stationary phase or to soluble toxins of Vip and Sip families secreted by vegetative cells. At the same time, numerous non-toxin virulence factors of Bt have been discovered, including metalloproteases, chitinases, aminopolyol antibiotics and nucleotide-mimicking moieties. These agents act at each stage of the B. thuringiensis invasion and contribute to cytotoxic properties of Bt strains enhancing toxin activity, ensuring host immune response evasion and participating in extracellular matrix degeneration. In this review we attempt to classify Bt virulence factors unrelated to major groups of protein toxins and discuss their putative role in the establishment of Bt specificity to various groups of insects.
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76
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Zheng JX, Sun X, Lin ZW, Qi GB, Tu HP, Wu Y, Jiang SB, Chen Z, Deng QW, Qu D, Yu ZJ. In vitro activities of daptomycin combined with fosfomycin or rifampin on planktonic and adherent linezolid-resistant isolates of Enterococcus faecalis. J Med Microbiol 2019; 68:493-502. [PMID: 30882300 DOI: 10.1099/jmm.0.000945] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
PURPOSE This study aimed to explore daptomycin combined with fosfomycin or rifampin against the planktonic and adherent linezolid-resistant isolates of Enterococcus faecalis. METHODOLOGY Four linezolid-resistant and four linezolid-sensitive isolates of E. faecalis which formed biofilms were collected for this study. Biofilm biomasses were detected by crystal violet staining and the adherent cells in the mature biofilms were quantified by c.f.u. determination. RESULTS Daptomycin alone, or combined with fosfomycin or rifampin (4×MIC) demonstrated bactericidal activities on the planktonic cells, and daptomycin combined with fosfomycin killed more planktonic cells (at least 1-log10 c.f.u. ml-1) than daptomycin or fosfomycin alone. Daptomycin alone (16×MIC) showed anti-biofilm activities against the mature biofilms and bactericidal activities on the adherent cells, while daptomycin combined with fosfomycin (16×MIC) demonstrated significantly more anti-biofilm activities than daptomycin or fosfomycin alone and effectively killed the adherent cells in the mature biofilms. The high concentration of daptomycin (512 mg l-1 ) combined with fosfomycin indicated more bactericidal activities on the adherent cells and more anti-biofilm activities against the mature biofilms than daptomycin 64 mg l-1 (16×MIC) combined with fosfomycin. The addition of rifampin increased the anti-biofilm and bactericidal activities of daptomycin against the mature biofilms and the adherent cells of two isolates, however, which was not observed in other isolates. CONCLUSIONS Daptomycin combined with fosfomycin demonstrated better effect on the planktonic and adherent linezolid-resistant isolates of E. faecalis than daptomycin or fosfomycin alone. The role of rifampin in the treatment of E. faecalis isolates is discrepant and needs more studies.
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Affiliation(s)
- Jin-Xin Zheng
- 1 Department of Infectious Diseases and the Key Lab of Endogenous Infection, Shenzhen Nanshan People's Hospital and The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen 518052, PR China.,2 Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, PR China
| | - Xiang Sun
- 1 Department of Infectious Diseases and the Key Lab of Endogenous Infection, Shenzhen Nanshan People's Hospital and The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen 518052, PR China
| | - Zhi-Wei Lin
- 1 Department of Infectious Diseases and the Key Lab of Endogenous Infection, Shenzhen Nanshan People's Hospital and The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen 518052, PR China
| | - Guo-Bin Qi
- 2 Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, PR China
| | - Hao-Peng Tu
- 1 Department of Infectious Diseases and the Key Lab of Endogenous Infection, Shenzhen Nanshan People's Hospital and The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen 518052, PR China
| | - Yang Wu
- 2 Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, PR China
| | - Si-Bo Jiang
- 3 Department of Pharmaceutics, University of Florida, Orlando 32827, USA
| | - Zhong Chen
- 2 Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, PR China.,1 Department of Infectious Diseases and the Key Lab of Endogenous Infection, Shenzhen Nanshan People's Hospital and The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen 518052, PR China
| | - Qi-Wen Deng
- 1 Department of Infectious Diseases and the Key Lab of Endogenous Infection, Shenzhen Nanshan People's Hospital and The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen 518052, PR China
| | - Di Qu
- 2 Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, PR China
| | - Zhi-Jian Yu
- 1 Department of Infectious Diseases and the Key Lab of Endogenous Infection, Shenzhen Nanshan People's Hospital and The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen 518052, PR China
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Chen D, Cao Y, Yu L, Tao Y, Zhou Y, Zhi Q, Lin H. Characteristics and influencing factors of amyloid fibers in S. mutans biofilm. AMB Express 2019; 9:31. [PMID: 30820691 PMCID: PMC6395465 DOI: 10.1186/s13568-019-0753-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 02/08/2019] [Indexed: 12/13/2022] Open
Abstract
There are signs that amyloid fibers exist in Streptococcus mutans biofilm recently. However, the characteristics of amyloid fibers and fibrillation influencing factors are unknown. In this study, we firstly used transmission electron microscopy (TEM) and atomic force microscopy (AFM) to observe the morphology of amyloid fibers in S. mutans. Then the extracted amyloid fibers from biofilm were studied for their characteristics. Further, the influencing factors, PH, temperature and eDNA, were investigated. Results showed there were mainly two morphologies of amyloid fibers in S. mutans, different in width. Amyloid fibers inhibitor-EGCG obviously destroyed biofilm at different stages, which is dose-dependent. The amount of amyloid fibers positively correlated with biofilm biomass in clinical isolates. Acidic pH and high temperature obviously accelerated amyloid fibrillation. During amyloid fibrillation, amyloid growth morphologies were observed by TEM and results showed two growth morphologies. Amyloid fibers formed complex with eDNA, which we call (a)eDNA. The molecular weight of (a)eDNA was similar to genomic DNA, greatly larger than that of eDNA in matrix. Combined use of DNase I and EGCG was more efficiently in inhibiting amyloid fibers and biofilm biomass. In conclusion, amyloid fibers are the crucial structures for S. mutans biofilm formation, showing two types of morphology. Acidic pH and temperature can obviously accelerate amyloid fibrillation. Amyloid fibers form complex with (a)eDNA and combined use of DNase and amyloid fiber inhibitor is more efficiently in inhibiting S. mutans biofilm formation.
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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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Affiliation(s)
- Antoine Loquet
- Institute of Chemistry & Biology of Membranes & Nanoobjects (UMR5248 CBMN), CNRS, Université Bordeaux, Institut Européen de Chimie et Biologie, 33600 Pessac, France.
| | - Sven J Saupe
- Institut de Biochimie et de Génétique Cellulaire (UMR 5095 IBGC), CNRS, Université Bordeaux, 33077 Bordeaux, France
| | - Diego Romero
- Grupo de Microbiología y Patología Vegetal-Unidad Asociada al CSIC, Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
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