51
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Angeles-Martinez L, Hatzimanikatis V. Spatio-temporal modeling of the crowding conditions and metabolic variability in microbial communities. PLoS Comput Biol 2021; 17:e1009140. [PMID: 34292935 PMCID: PMC8297787 DOI: 10.1371/journal.pcbi.1009140] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 06/01/2021] [Indexed: 11/22/2022] Open
Abstract
The metabolic capabilities of the species and the local environment shape the microbial interactions in a community either through the exchange of metabolic products or the competition for the resources. Cells are often arranged in close proximity to each other, creating a crowded environment that unevenly reduce the diffusion of nutrients. Herein, we investigated how the crowding conditions and metabolic variability among cells shape the dynamics of microbial communities. For this, we developed CROMICS, a spatio-temporal framework that combines techniques such as individual-based modeling, scaled particle theory, and thermodynamic flux analysis to explicitly incorporate the cell metabolism and the impact of the presence of macromolecular components on the nutrients diffusion. This framework was used to study two archetypical microbial communities (i) Escherichia coli and Salmonella enterica that cooperate with each other by exchanging metabolites, and (ii) two E. coli with different production level of extracellular polymeric substances (EPS) that compete for the same nutrients. In the mutualistic community, our results demonstrate that crowding enhanced the fitness of cooperative mutants by reducing the leakage of metabolites from the region where they are produced, avoiding the resource competition with non-cooperative cells. Moreover, we also show that E. coli EPS-secreting mutants won the competition against the non-secreting cells by creating less dense structures (i.e. increasing the spacing among the cells) that allow mutants to expand and reach regions closer to the nutrient supply point. A modest enhancement of the relative fitness of EPS-secreting cells over the non-secreting ones were found when the crowding effect was taken into account in the simulations. The emergence of cell-cell interactions and the intracellular conflicts arising from the trade-off between growth and the secretion of metabolites or EPS could provide a local competitive advantage to one species, either by supplying more cross-feeding metabolites or by creating a less dense neighborhood. Microbial communities play a key role in biogeochemical cycles, bioremediation, and human health. In crowded microbial systems such as biofilms and cellular aggregates, the close proximity between individual cells reduces the free space for the nutrients diffusion. To model the heterogeneous nature of these microbial systems, we developed CROMICS, a framework that integrates the information about the metabolic capabilities of each individual cell as well as the size and location of cells and macromolecules in the medium. The interactions among the individuals arise naturally through competition for or the exchange of metabolites. We show how the presence of mutants and a reduced diffusion in crowded environments can perturb the local availability of nutrients and therefore modify the dynamics of a microbial community. The discovered mechanisms underlying the microbial interactions in crowded systems together with the developed framework represent a valuable starting point for future studies of the interplay of human microbiome and host metabolism, the pathogen invasion, and the evaluation of antibiotic effectiveness.
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Affiliation(s)
- Liliana Angeles-Martinez
- Laboratory of Computational Systems Biotechnology, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Vassily Hatzimanikatis
- Laboratory of Computational Systems Biotechnology, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
- * E-mail:
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52
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Sivasubramanian R, Chen GH, Mackey HR. The effectiveness of divalent cation addition for highly saline activated sludge cultures: Influence of monovalent/divalent ratio and specific cations. CHEMOSPHERE 2021; 274:129864. [PMID: 33979942 DOI: 10.1016/j.chemosphere.2021.129864] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/18/2021] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
Saline wastewaters are prevalent in various industries and pose challenges to stable biological treatment. Increasing monovalent cation concentrations are commonly reported to deteriorate treatment and settling performance, while divalent cations can enhance flocculation and settling. However, many previous studies were performed at relatively low salinities and reports conflict on whether concentrations of monovalent cations, divalent cations, or their ratio (M/D) are most critical. This study investigates whether addition of divalent cations shows the same benefits at high salinity (∼40 g NaCl.L-1) and whether divalent ion concentration or M/D is a better predictor of enhancement. Nine sequencing batch reactors were operated at 0.8 M NaCl or KCl monovalent salt concentration, and the concentration of divalent cations (Ca2+ and Mg2+) was varied. M/D was found to be the critical factor that consistently influenced sludge characteristics. It was particularly important in describing hydrophobicity, sludge volume index (SVI) and specific oxygen uptake rate (SOUR), with rpartial of -0.879, 0.971 and 0.966 respectively in models that had an r2adj greater than 0.93. Lower M/D also increased biomass concentrations and reduced extracellular polysaccharides, the latter which in turn correlated strongly with many shape and surface charge measures. The specific monovalent salt (Na+ or K+) influenced treatment performance, biomass concentrations, hydrophobicity, SOUR, extracellular protein and SVI. The specific divalent cation was only important in describing SVI, where Mg2+ was beneficial. Overall, this study shows that addition of divalent cations can greatly benefit high salinity activated sludge systems by improving the sludge structure, settling and organic removal.
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Affiliation(s)
- Raghavendran Sivasubramanian
- Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar
| | - Guang-Hao Chen
- Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Hamish Robert Mackey
- Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar.
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53
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Xiang S, Fan Z, Sun D, Zhu T, Ming J, Chen X. Near-Infrared Light Enhanced Peroxidase-Like Activity of PEGylated Palladium Nanozyme for Highly Efficient Biofilm Eradication. J Biomed Nanotechnol 2021; 17:1131-1147. [PMID: 34167627 DOI: 10.1166/jbn.2021.3095] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The overall eradication of biofilm-mode growing bacteria holds significant key to the answer of a series of infection-related health problems. However, the extracellular matrix of bacteria biofilms disables the traditional antimicrobials and, more unfortunately, hampers the development of the anti-infectious alternatives. Therefore, highly effective antimicrobial agents are an urgent need for biofilm-infection control. Herein, a PEGylated palladium nanozyme (Pd-PEG) with peroxidase (POD)-like activity for highly efficient biofilm infection control is reported. Pd-PEG also shows the intrinsic photothermal effect as well as near-infrared (NIR) light-enhanced POD-like activity in the acidic environment, thereby massively destroying the biofilm matrix and killing the adhering bacteria. Importantly, the antimicrobial mechanism of the synergistic treatment based on Pd-PEG+H₂O₂+NIR combination was disclosed. In vitro and in vivo results illustrated the designed Pd-PEG+H₂O₂ +NIR treatment reagent possessed outstanding antibacterial and biofilms elimination effects with negligible biotoxicity. This work hopefully facilitates the development of metal-based nanozymes in biofilm related infectious diseases.
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Affiliation(s)
- Sijin Xiang
- State Key Laboratory for Physical Chemistry of Solid Surfaces, Research Center for Nano-Preparation Technology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Zhongxiong Fan
- Department of Biomaterials, College of Materials, Research Center of Biomedical Engineering of Xiamen & Key Laboratory of Biomedical Engineering of Fujian Province & Fujian Provincial Key Laboratory for Soft Functional Materials Research, Xiamen University, Xiamen 361005, China
| | - Duo Sun
- State Key Laboratory for Physical Chemistry of Solid Surfaces, Research Center for Nano-Preparation Technology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Tianbao Zhu
- State Key Laboratory for Physical Chemistry of Solid Surfaces, Research Center for Nano-Preparation Technology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jiang Ming
- State Key Laboratory for Physical Chemistry of Solid Surfaces, Research Center for Nano-Preparation Technology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiaolan Chen
- State Key Laboratory for Physical Chemistry of Solid Surfaces, Research Center for Nano-Preparation Technology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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54
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Hermann L, Mais CN, Czech L, Smits SHJ, Bange G, Bremer E. The ups and downs of ectoine: structural enzymology of a major microbial stress protectant and versatile nutrient. Biol Chem 2021; 401:1443-1468. [PMID: 32755967 DOI: 10.1515/hsz-2020-0223] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 07/22/2020] [Indexed: 12/13/2022]
Abstract
Ectoine and its derivative 5-hydroxyectoine are compatible solutes and chemical chaperones widely synthesized by Bacteria and some Archaea as cytoprotectants during osmotic stress and high- or low-growth temperature extremes. The function-preserving attributes of ectoines led to numerous biotechnological and biomedical applications and fostered the development of an industrial scale production process. Synthesis of ectoines requires the expenditure of considerable energetic and biosynthetic resources. Hence, microorganisms have developed ways to exploit ectoines as nutrients when they are no longer needed as stress protectants. Here, we summarize our current knowledge on the phylogenomic distribution of ectoine producing and consuming microorganisms. We emphasize the structural enzymology of the pathways underlying ectoine biosynthesis and consumption, an understanding that has been achieved only recently. The synthesis and degradation pathways critically differ in the isomeric form of the key metabolite N-acetyldiaminobutyric acid (ADABA). γ-ADABA serves as preferred substrate for the ectoine synthase, while the α-ADABA isomer is produced by the ectoine hydrolase as an intermediate in catabolism. It can serve as internal inducer for the genetic control of ectoine catabolic genes via the GabR/MocR-type regulator EnuR. Our review highlights the importance of structural enzymology to inspire the mechanistic understanding of metabolic networks at the biological scale.
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Affiliation(s)
- Lucas Hermann
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, Karl-von Frisch Str. 8, D-35043 Marburg, Germany.,Biochemistry and Synthetic Biology of Microbial Metabolism Group, Max Planck Institute for Terrestrial Microbiology, Karl-von Frisch Str. 10, D-35043 Marburg, Germany
| | - Christopher-Nils Mais
- Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein Str. 6, D-35043 Marburg, Germany
| | - Laura Czech
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, Karl-von Frisch Str. 8, D-35043 Marburg, Germany.,Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein Str. 6, D-35043 Marburg, Germany
| | - Sander H J Smits
- Center for Structural Studies, Heinrich Heine University Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany.,Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Gert Bange
- Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein Str. 6, D-35043 Marburg, Germany
| | - Erhard Bremer
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, Karl-von Frisch Str. 8, D-35043 Marburg, Germany.,Center for Synthetic Microbiology (SYNMIKRO), Philipps University Marburg, Hans-Meerwein Str. 6, D-35043 Marburg, Germany
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55
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Soto W, Nishiguchi MK. Environmental Stress Selects for Innovations That Drive Vibrio Symbiont Diversity. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.616973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Symbiotic bacteria in the Vibrionaceae are a dynamic group of γ-Proteobacteria that are commonly found throughout the world. Although they primarily are free-living in the environment, they can be commonly found associated with various Eukarya, either as beneficial or pathogenic symbionts. Interestingly, this dual lifestyle (free-living or in symbiosis) enables the bacteria to have enormous ecological breadth, where they can accommodate a variety of stresses in both stages. Here, we discuss some of the most common stressors that Vibrio bacteria encounter when in their free-living state or associated with an animal host, and how some of the mechanisms that are used to cope with these stressors can be used as an evolutionary advantage that increases their diversity both in the environment and within their specific hosts.
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56
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Arias SL, Brito IL. Biophysical determinants of biofilm formation in the gut. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2021; 18:100275. [PMID: 34504987 PMCID: PMC8423371 DOI: 10.1016/j.cobme.2021.100275] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The gastrointestinal (GI) tract harbors the most complex microbial ecosystem in the human body. The mucosal layer that covers the GI tract serves as a polymer-based defensive barrier that prevents the microbiome from reaching the epithelium and disseminating inside the body. Colonization of the mucus may result in the formation of structured polymicrobial communities or biofilms, a hallmark in pathologies such as colorectal cancer, inflammatory bowel disease, and chronic gut wounds. However, the mechanisms by which multispecies biofilms establish on the gut mucosa is unknown. Whether mucus-associated biofilms exist as part of a healthy mucosal barrier is still debated. Here, we discuss the impact that diet and microbial-derived polymers has on mucus structure and microcolony formation and highlight relevant biophysical forces that further shape nascent biofilms.
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Affiliation(s)
- Sandra L Arias
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14850
| | - Ilana L Brito
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14850
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57
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Zhang W, Bertinetti L, Blank KG, Dimova R, Gao C, Schneck E, Fratzl P. Spatiotemporal Measurement of Osmotic Pressures by FRET Imaging. Angew Chem Int Ed Engl 2021; 60:6488-6495. [PMID: 33188706 PMCID: PMC7986915 DOI: 10.1002/anie.202011983] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 11/06/2020] [Indexed: 12/21/2022]
Abstract
Osmotic pressures (OPs) play essential roles in biological processes and numerous technological applications. However, the measurement of OP in situ with spatiotemporal resolution has not been achieved so far. Herein, we introduce a novel kind of OP sensor based on liposomes loaded with water-soluble fluorescent dyes exhibiting resonance energy transfer (FRET). The liposomes experience volume changes in response to OP due to water outflux. The FRET efficiency depends on the average distance between the entrapped dyes and thus provides a direct measure of the OP surrounding each liposome. The sensors exhibit high sensitivity to OP in the biologically relevant range of 0-0.3 MPa in aqueous solutions of salt, small organic molecules, and macromolecules. With the help of FRET microscopy, we demonstrate the feasibility of spatiotemporal OP imaging, which can be a promising new tool to investigate phenomena involving OPs and their dynamics in biology and technology.
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Affiliation(s)
- Wenbo Zhang
- Department of BiomaterialsMax Planck Institute of Colloids and Interfaces14476PotsdamGermany
| | - Luca Bertinetti
- Department of BiomaterialsMax Planck Institute of Colloids and Interfaces14476PotsdamGermany
| | - Kerstin G. Blank
- Mechano(bio)chemistryMax Planck Institute of Colloids and Interfaces14476PotsdamGermany
| | - Rumiana Dimova
- Department of Theory & Bio-SystemsMax Planck Institute of Colloids and Interfaces14476PotsdamGermany
| | - Changyou Gao
- MOE Key Laboratory of Macromolecular Synthesis and FunctionalizationDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou310027China
| | - Emanuel Schneck
- Department of BiomaterialsMax Planck Institute of Colloids and Interfaces14476PotsdamGermany
- Department of PhysicsTechnische Universität Darmstadt64289DarmstadtGermany
| | - Peter Fratzl
- Department of BiomaterialsMax Planck Institute of Colloids and Interfaces14476PotsdamGermany
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58
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Zhang W, Bertinetti L, Blank KG, Dimova R, Gao C, Schneck E, Fratzl P. Spatiotemporal Measurement of Osmotic Pressures by FRET Imaging. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202011983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Wenbo Zhang
- Department of Biomaterials Max Planck Institute of Colloids and Interfaces 14476 Potsdam Germany
| | - Luca Bertinetti
- Department of Biomaterials Max Planck Institute of Colloids and Interfaces 14476 Potsdam Germany
| | - Kerstin G. Blank
- Mechano(bio)chemistry Max Planck Institute of Colloids and Interfaces 14476 Potsdam Germany
| | - Rumiana Dimova
- Department of Theory & Bio-Systems Max Planck Institute of Colloids and Interfaces 14476 Potsdam Germany
| | - Changyou Gao
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 China
| | - Emanuel Schneck
- Department of Biomaterials Max Planck Institute of Colloids and Interfaces 14476 Potsdam Germany
- Department of Physics Technische Universität Darmstadt 64289 Darmstadt Germany
| | - Peter Fratzl
- Department of Biomaterials Max Planck Institute of Colloids and Interfaces 14476 Potsdam Germany
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Abstract
Biofilms are structured communities formed by a single or multiple microbial species. Within biofilms, bacteria are embedded into extracellular matrix, allowing them to build macroscopic objects. Biofilm structure can respond to environmental changes such as the presence of antibiotics or predators. By adjusting expression levels of surface and extracellular matrix components, bacteria tune cell-to-cell interactions. One major challenge in the field is the fact that these components are very diverse among different species. Deciphering how physical interactions within biofilms are affected by changes in gene expression is a promising approach to obtaining a more unified picture of how bacteria modulate biofilms. This review focuses on recent advances in characterizing attractive and repulsive forces between bacteria in correlation with biofilm structure, dynamics, and spreading. How bacteria control physical interactions to maximize their fitness is an emerging theme.
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Affiliation(s)
- Berenike Maier
- Institute for Biological Physics and Center for Molecular Medicine Cologne, University of Cologne, 50674 Cologne, Germany;
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60
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Arjes HA, Willis L, Gui H, Xiao Y, Peters J, Gross C, Huang KC. Three-dimensional biofilm colony growth supports a mutualism involving matrix and nutrient sharing. eLife 2021; 10:e64145. [PMID: 33594973 PMCID: PMC7925131 DOI: 10.7554/elife.64145] [Citation(s) in RCA: 10] [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: 10/19/2020] [Accepted: 02/15/2021] [Indexed: 12/16/2022] Open
Abstract
Life in a three-dimensional biofilm is typical for many bacteria, yet little is known about how strains interact in this context. Here, we created essential gene CRISPR interference knockdown libraries in biofilm-forming Bacillus subtilis and measured competitive fitness during colony co-culture with wild type. Partial knockdown of some translation-related genes reduced growth rates and led to out-competition. Media composition led some knockdowns to compete differentially as biofilm versus non-biofilm colonies. Cells depleted for the alanine racemase AlrA died in monoculture but survived in a biofilm colony co-culture via nutrient sharing. Rescue was enhanced in biofilm colony co-culture with a matrix-deficient parent due to a mutualism involving nutrient and matrix sharing. We identified several examples of mutualism involving matrix sharing that occurred in three-dimensional biofilm colonies but not when cultured in two dimensions. Thus, growth in a three-dimensional colony can promote genetic diversity through sharing of secreted factors and may drive evolution of mutualistic behavior.
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Affiliation(s)
- Heidi A Arjes
- Department of Bioengineering, Stanford University School of MedicineStanfordUnited States
| | - Lisa Willis
- Department of Bioengineering, Stanford University School of MedicineStanfordUnited States
| | - Haiwen Gui
- Department of Bioengineering, Stanford University School of MedicineStanfordUnited States
| | - Yangbo Xiao
- Department of Bioengineering, Stanford University School of MedicineStanfordUnited States
| | - Jason Peters
- Department of Cell and Tissue Biology, University of California San FranciscoSan FranciscoUnited States
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-MadisonMadisonUnited States
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin-MadisonMadisonUnited States
- Department of Bacteriology, University of Wisconsin-MadisonMadisonUnited States
- Department of Medical Microbiology and Immunology, University of Wisconsin-MadisonMadisonUnited States
| | - Carol Gross
- Department of Cell and Tissue Biology, University of California San FranciscoSan FranciscoUnited States
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University School of MedicineStanfordUnited States
- Department of Microbiology & Immunology, Stanford University School of MedicineStanfordUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
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61
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Booth SC, Rice SA. Influence of interspecies interactions on the spatial organization of dual species bacterial communities. Biofilm 2021; 2:100035. [PMID: 33447820 PMCID: PMC7798468 DOI: 10.1016/j.bioflm.2020.100035] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 07/09/2020] [Accepted: 08/03/2020] [Indexed: 12/11/2022] Open
Abstract
Interspecies interactions in bacterial biofilms have important impacts on the composition and function of communities in natural and engineered systems. To investigate these interactions, synthetic communities provide experimentally tractable systems. Biofilms grown on agar-surfaces have been used for investigating the eco-evolutionary and biophysical forces that determine community composition and spatial distribution of bacteria. Prior studies have used genetically identical bacterial strains and strains with specific mutations, that express different fluorescent proteins, to investigate intraspecies interactions. Here, we investigated interspecies interactions and, specifically, determined the community composition and spatial distribution in synthetic communities of Pseudomonas aeruginosa, Pseudomonas protegens and Klebsiella pneumoniae. Using quantitative microscopic imaging, we found that interspecies interactions in multispecies colonies were influenced by type IV pilus mediated motility, extracellular matrix secretion, environmental parameters, and these effects were also influenced by the specific partner in the dual species combinations. These results indicate that the patterns observable in mixed species colonies can be used to understand the mechanisms that drive interspecies interactions, which are dependent on the interplay between specific species’ physiology and environmental conditions. Spatial patterns in bacterial colonies are species and interaction dependent. Surface motility and extracellar matrix production affect interspecies interactions. Agar surface colonies show how bacteria interact in biofilms.
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Affiliation(s)
- Sean C Booth
- The Singapore Centre for Environmental Life Sciences Engineering, Singapore
| | - Scott A Rice
- The Singapore Centre for Environmental Life Sciences Engineering, Singapore.,The School of Biological Sciences, Nanyang Technological University, Singapore.,The Ithree Institute, The University of Technology Sydney, Australia
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62
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Maikranz E, Santen L. Theoretical modelling of competitive microbial range expansion with heterogeneous mechanical interactions. Phys Biol 2021; 18:016008. [PMID: 33197896 DOI: 10.1088/1478-3975/abcae9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Microbial range expansion experiments provide insight into the complex link between dynamic structure, pattern formation and evolutionary dynamics of growing populations. In this work, we develop a theoretical model in order to investigate the interplay of growth statistics and mechanical interactions which are implemented as division driven pushing and swapping of cells. For the case of the competitive growth of a strongly and a weakly interacting strain we investigate the influence of different mean division times, as well as different mechanical interactions on the development of the colony. Our results show that the susceptibility to cell division induced pushing has a much stronger influence on the structure of the colony than cell sorting towards the colony's perimeter. Motivated by microbial range expansion experiments of Neisseria gonorrhoeae bacteria, we also consider the influence of mutating cells on the structure of the colony. We show that the outgrowth of the three different strains is strongly influenced by the relative strengths of their mechanical interaction. The experimentally observed patterns are reproduced for mechanical interactions of the mutants, which range between those of the strongly and weakly interacting strain.
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Affiliation(s)
- E Maikranz
- Theoretical Physics, Saarland University, Campus E2 6, D-66123 Saarbrücken, Germany
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63
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Yin W, Xu S, Wang Y, Zhang Y, Chou SH, Galperin MY, He J. Ways to control harmful biofilms: prevention, inhibition, and eradication. Crit Rev Microbiol 2020; 47:57-78. [PMID: 33356690 DOI: 10.1080/1040841x.2020.1842325] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Biofilms are complex microbial architectures that encase microbial cells in a matrix comprising self-produced extracellular polymeric substances. Microorganisms living in biofilms are much more resistant to hostile environments than their planktonic counterparts and exhibit enhanced resistance against the microbicides. From the human perspective, biofilms can be classified into beneficial, neutral, and harmful. Harmful biofilms impact food safety, cause plant and animal diseases, and threaten medical fields, making it urgent to develop effective and robust strategies to control harmful biofilms. In this review, we discuss various strategies to control biofilm formation on infected tissues, implants, and medical devices. We classify the current strategies into three main categories: (i) changing the properties of susceptible surfaces to prevent biofilm formation; (ii) regulating signalling pathways to inhibit biofilm formation; (iii) applying external forces to eradicate the biofilm. We hope this review would motivate the development of innovative and effective strategies for controlling harmful biofilms.
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Affiliation(s)
- Wen Yin
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, PR China
| | - Siyang Xu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, PR China
| | - Yiting Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, PR China
| | - Yuling Zhang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, PR China
| | - Shan-Ho Chou
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, PR China
| | - Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, PR China
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64
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Jin X, Marshall JS. Mechanics of biofilms formed of bacteria with fimbriae appendages. PLoS One 2020; 15:e0243280. [PMID: 33290393 PMCID: PMC7723297 DOI: 10.1371/journal.pone.0243280] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 11/18/2020] [Indexed: 11/23/2022] Open
Abstract
Gram-negative bacteria, as well as some Gram-positive bacteria, possess hair-like appendages known as fimbriae, which play an important role in adhesion of the bacteria to surfaces or to other bacteria. Unlike the sex pili or flagellum, the fimbriae are quite numerous, with of order 1000 fimbriae appendages per bacterial cell. In this paper, a recently developed hybrid model for bacterial biofilms is used to examine the role of fimbriae tension force on the mechanics of bacterial biofilms. Each bacterial cell is represented in this model by a spherocylindrical particle, which interact with each other through collision, adhesion, lubrication force, and fimbrial force. The bacterial cells absorb water and nutrients and produce extracellular polymeric substance (EPS). The flow of water and EPS, and nutrient diffusion within these substances, is computed using a continuum model that accounts for important effects such as osmotic pressure gradient, drag force on the bacterial cells, and viscous shear. The fimbrial force is modeled using an outer spherocylinder capsule around each cell, which can transmit tensile forces to neighboring cells with which the fimbriae capsule collides. We find that the biofilm structure during the growth process is dominated by a balance between outward drag force on the cells due to the EPS flow away from the bacterial colony and the inward tensile fimbrial force acting on chains of cells connected by adhesive fimbriae appendages. The fimbrial force also introduces a large rotational motion of the cells and disrupts cell alignment caused by viscous torque imposed by the EPS flow. The current paper characterizes the competing effects of EPS drag and fimbrial force using a series of computations with different values of the ratio of EPS to bacterial cell production rate and different numbers of fimbriae per cell.
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Affiliation(s)
- Xing Jin
- Department of Mechanical Engineering, University of Vermont, Burlington, VT, United States of America
| | - Jeffrey S. Marshall
- Department of Mechanical Engineering, University of Vermont, Burlington, VT, United States of America
- * E-mail:
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65
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Casey D, Sleator RD. A genomic analysis of osmotolerance in Staphylococcus aureus. Gene 2020; 767:145268. [PMID: 33157201 DOI: 10.1016/j.gene.2020.145268] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 09/07/2020] [Accepted: 10/20/2020] [Indexed: 12/12/2022]
Abstract
A key phenotypic characteristic of the Gram-positive bacterial pathogen, Staphylococcus aureus, is its ability to grow in low aw environments. A homology transfer based approach, using the well characterised osmotic stress response systems of Bacillus subtilis and Escherichia coli, was used to identify putative osmotolerance loci in Staphylococcus aureus ST772-MRSA-V. A total of 17 distinct putative hyper and hypo-osmotic stress response systems, comprising 78 genes, were identified. The ST772-MRSA-V genome exhibits significant degeneracy in terms of the osmotic stress response; with three copies of opuD, two copies each of nhaK and mrp/mnh, and five copies of opp. Furthermore, regulation of osmotolerance in ST772-MRSA-V appears to be mediated at the transcriptional, translational, and post-translational levels.
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Affiliation(s)
- Dylan Casey
- Department of Biological Sciences, Munster Technological University, Bishopstown Campus, Cork, Ireland
| | - Roy D Sleator
- Department of Biological Sciences, Munster Technological University, Bishopstown Campus, Cork, Ireland.
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66
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Huang F, Chen JY, Ouyang JM. Comparison of the inhibition of high phosphate-induced smooth muscle cell calcification by Porphyra yezoensis and Astragalus polysaccharides. J Funct Foods 2020. [DOI: 10.1016/j.jff.2020.104160] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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67
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Otto SB, Martin M, Schäfer D, Hartmann R, Drescher K, Brix S, Dragoš A, Kovács ÁT. Privatization of Biofilm Matrix in Structurally Heterogeneous Biofilms. mSystems 2020; 5:e00425-20. [PMID: 32753507 PMCID: PMC7406226 DOI: 10.1128/msystems.00425-20] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/13/2020] [Indexed: 12/19/2022] Open
Abstract
The self-produced biofilm provides beneficial protection for the enclosed cells, but the costly production of matrix components makes producer cells susceptible to cheating by nonproducing individuals. Despite detrimental effects of nonproducers, biofilms can be heterogeneous, with isogenic nonproducers being a natural consequence of phenotypic differentiation processes. For instance, in Bacillus subtilis biofilm cells differ in production of the two major matrix components, the amyloid fiber protein TasA and exopolysaccharides (EPS), demonstrating different expression levels of corresponding matrix genes. This raises questions regarding matrix gene expression dynamics during biofilm development and the impact of phenotypic nonproducers on biofilm robustness. Here, we show that biofilms are structurally heterogeneous and can be separated into strongly and weakly associated clusters. We reveal that spatiotemporal changes in structural heterogeneity correlate with matrix gene expression, with TasA playing a key role in biofilm integrity and timing of development. We show that the matrix remains partially privatized by the producer subpopulation, where cells tightly stick together even when exposed to shear stress. Our results support previous findings on the existence of "weak points" in seemingly robust biofilms as well as on the key role of linkage proteins in biofilm formation. Furthermore, we provide a starting point for investigating the privatization of common goods within isogenic populations.IMPORTANCE Biofilms are communities of bacteria protected by a self-produced extracellular matrix. The detrimental effects of nonproducing individuals on biofilm development raise questions about the dynamics between community members, especially when isogenic nonproducers exist within wild-type populations. We asked ourselves whether phenotypic nonproducers impact biofilm robustness, and where and when this heterogeneity of matrix gene expression occurs. Based on our results, we propose that the matrix remains partly privatized by the producing subpopulation, since producing cells stick together when exposed to shear stress. The important role of linkage proteins in robustness and development of the structurally heterogeneous biofilm provides an entry into studying the privatization of common goods within isogenic populations.
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Affiliation(s)
- Simon B Otto
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Marivic Martin
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Daniel Schäfer
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Raimo Hartmann
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Knut Drescher
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Philipps-Universität Marburg, Marburg, Germany
| | - Susanne Brix
- Disease Systems Immunology Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Anna Dragoš
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Ákos T Kovács
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
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68
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Krmar J, Protić A, Đajić N, Zečević M, Otašević B. Chromatographic and computational lipophilicity assessment of novel antibiofilm agents. J LIQ CHROMATOGR R T 2020. [DOI: 10.1080/10826076.2020.1777154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Jovana Krmar
- Department of Drug Analysis, University of Belgrade–Faculty of Pharmacy, Belgrade, Serbia
| | - Ana Protić
- Department of Drug Analysis, University of Belgrade–Faculty of Pharmacy, Belgrade, Serbia
| | - Nevena Đajić
- Department of Drug Analysis, University of Belgrade–Faculty of Pharmacy, Belgrade, Serbia
| | - Mira Zečević
- Department of Drug Analysis, University of Belgrade–Faculty of Pharmacy, Belgrade, Serbia
| | - Biljana Otašević
- Department of Drug Analysis, University of Belgrade–Faculty of Pharmacy, Belgrade, Serbia
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69
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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: 540] [Impact Index Per Article: 135.0] [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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70
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Zhang Q, Guo Q, Chen Q, Zhao X, Pennycook SJ, Chen H. Highly Efficient 2D NIR-II Photothermal Agent with Fenton Catalytic Activity for Cancer Synergistic Photothermal-Chemodynamic Therapy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1902576. [PMID: 32274298 PMCID: PMC7141019 DOI: 10.1002/advs.201902576] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/19/2019] [Indexed: 05/19/2023]
Abstract
Photothermal therapy (PTT) has emerged as a promising cancer therapeutic modality with high therapeutic specificity, however, its therapeutic effectiveness is limited by available high-efficiency photothermal agents (PTAs), especially in the second near-infrared (NIR-II) biowindow. Here, based on facile liquid-exfoliated FePS3 nanosheets, a highly efficient NIR-II PTA with its photothermal conversion efficiency of up to 43.3% is demonstrated, which is among the highest reported levels in typical PTAs. More importantly, such Fe-based 2D nanosheets also show superior Fenton catalytic activity facilitated by their ultrahigh specific surface area, simultaneously enabling cancer chemodynamic therapy (CDT). Impressively, the efficiency of CDT could be further remarkably enhanced by its photothermal effect, leading to cancer synergistic PTT/CDT. Both in vitro and in vivo studies reveal a highly efficient tumor ablation under NIR-II light irradiation. This work provides a paradigm for cancer CDT and PTT in the NIR-II biowindow via a single 2D nanoplatform with desired therapeutic effect. Furthermore, with additional possibilities for magnetic resonance imaging, photoacoustic tomography, as well as drug loading, this Fe-based 2D material could potentially serve as a 2D "all-in-one" theranostic nanoplatform.
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Affiliation(s)
- Qiuhong Zhang
- State Key Laboratory of High Performance Ceramics and Superfine MicrostructureShanghai Institute of CeramicsChinese Academy of SciencesShanghai200050P. R. China
- Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of SciencesBeijing100049P. R. China
| | - Qiangbing Guo
- Department of Materials Science and EngineeringNational University of SingaporeSingapore117575Singapore
| | - Qian Chen
- State Key Laboratory of High Performance Ceramics and Superfine MicrostructureShanghai Institute of CeramicsChinese Academy of SciencesShanghai200050P. R. China
- Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of SciencesBeijing100049P. R. China
| | - Xiaoxu Zhao
- Department of Materials Science and EngineeringNational University of SingaporeSingapore117575Singapore
| | - Stephen J. Pennycook
- Department of Materials Science and EngineeringNational University of SingaporeSingapore117575Singapore
- NUSNNI‐NanocoreNational University of SingaporeSingapore117411Singapore
| | - Hangrong Chen
- State Key Laboratory of High Performance Ceramics and Superfine MicrostructureShanghai Institute of CeramicsChinese Academy of SciencesShanghai200050P. R. China
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71
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Nonuniform growth and surface friction determine bacterial biofilm morphology on soft substrates. Proc Natl Acad Sci U S A 2020; 117:7622-7632. [PMID: 32193350 DOI: 10.1073/pnas.1919607117] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During development, organisms acquire three-dimensional (3D) shapes with important physiological consequences. While basic mechanisms underlying morphogenesis are known in eukaryotes, it is often difficult to manipulate them in vivo. To circumvent this issue, here we present a study of developing Vibrio cholerae biofilms grown on agar substrates in which the spatiotemporal morphological patterns were altered by varying the agar concentration. Expanding biofilms are initially flat but later undergo a mechanical instability and become wrinkled. To gain mechanistic insights into this dynamic pattern-formation process, we developed a model that considers diffusion of nutrients and their uptake by bacteria, bacterial growth/biofilm matrix production, mechanical deformation of both the biofilm and the substrate, and the friction between them. Our model shows quantitative agreement with experimental measurements of biofilm expansion dynamics, and it accurately predicts two distinct spatiotemporal patterns observed in the experiments-the wrinkles initially appear either in the peripheral region and propagate inward (soft substrate/low friction) or in the central region and propagate outward (stiff substrate/high friction). Our results, which establish that nonuniform growth and friction are fundamental determinants of stress anisotropy and hence biofilm morphology, are broadly applicable to bacterial biofilms with similar morphologies and also provide insight into how other bacterial biofilms form distinct wrinkle patterns. We discuss the implications of forming undulated biofilm morphologies, which may enhance the availability of nutrients and signaling molecules and serve as a "bet hedging" strategy.
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72
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Gagliano MC, Sudmalis D, Pei R, Temmink H, Plugge CM. Microbial Community Drivers in Anaerobic Granulation at High Salinity. Front Microbiol 2020; 11:235. [PMID: 32174895 PMCID: PMC7054345 DOI: 10.3389/fmicb.2020.00235] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 01/31/2020] [Indexed: 01/24/2023] Open
Abstract
In the recent years anaerobic sludge granulation at elevated salinities in upflow anaerobic sludge blanket (UASB) reactors has been investigated in few engineering based studies, never addressing the microbial community structural role in driving aggregation and keeping granules stability. In this study, the combination of different techniques was applied in order to follow the microbial community members and their structural dynamics in granules formed at low (5 g/L Na+) and high (20 g/L Na+) salinity conditions. Experiments were carried out in four UASB reactors fed with synthetic wastewater, using two experimental set-ups. By applying 16S rRNA gene analysis, the comparison of granules grown at low and high salinity showed that acetotrophic Methanosaeta harundinacea was the dominant methanogen at both salinities, while the dominant bacteria changed. At 5 g/L Na+, cocci chains of Streptoccoccus were developing, while at 20 g/L Na+ members of the family Defluviitaleaceae formed long filaments. By means of Fluorescence in Situ Hybridization (FISH) and Scanning Electron Microscopy (SEM), it was shown that aggregation of Methanosaeta in compact clusters and the formation of filaments of Streptoccoccus and Defluviitaleaceae during the digestion time were the main drivers for the granulation at low and high salinity. Interestingly, when the complex protein substrate (tryptone) in the synthetic wastewater was substituted with single amino acids (proline, leucine and glutamic acid), granules at high salinity (20 g/L Na+) were not formed. This corresponded to a decrease of Methanosaeta relative abundance and a lack of compact clustering, together with disappearance of Defluviitaleaceae and consequent absence of bacterial filaments within the dispersed biomass. In these conditions, a biofilm was growing on the glass wall of the reactor instead, highlighting that a complex protein substrate such as tryptone can contribute to granules formation at elevated salinity.
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Affiliation(s)
- Maria Cristina Gagliano
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands.,Wetsus - European Centre of Excellence for Sustainable Water Technology, Leeuwarden, Netherlands
| | - Dainis Sudmalis
- Department of Environmental Technology, Wageningen University & Research, Wageningen, Netherlands
| | - Ruizhe Pei
- Wetsus - European Centre of Excellence for Sustainable Water Technology, Leeuwarden, Netherlands
| | - Hardy Temmink
- Wetsus - European Centre of Excellence for Sustainable Water Technology, Leeuwarden, Netherlands.,Department of Environmental Technology, Wageningen University & Research, Wageningen, Netherlands
| | - Caroline M Plugge
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands.,Wetsus - European Centre of Excellence for Sustainable Water Technology, Leeuwarden, Netherlands
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73
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Díaz-Pascual F, Hartmann R, Lempp M, Vidakovic L, Song B, Jeckel H, Thormann KM, Yildiz FH, Dunkel J, Link H, Nadell CD, Drescher K. Breakdown of Vibrio cholerae biofilm architecture induced by antibiotics disrupts community barrier function. Nat Microbiol 2019; 4:2136-2145. [PMID: 31659297 PMCID: PMC6881181 DOI: 10.1038/s41564-019-0579-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 09/06/2019] [Indexed: 01/01/2023]
Abstract
Bacterial cells in nature are frequently exposed to changes in their chemical environment1,2. The response mechanisms of isolated cells to such stimuli have been investigated in great detail. By contrast, little is known about the emergent multicellular responses to environmental changes, such as antibiotic exposure3-7, which may hold the key to understanding the structure and functions of the most common type of bacterial communities: biofilms. Here, by monitoring all individual cells in Vibrio cholerae biofilms during exposure to antibiotics that are commonly administered for cholera infections, we found that translational inhibitors cause strong effects on cell size and shape, as well as biofilm architectural properties. We identified that single-cell-level responses result from the metabolic consequences of inhibition of protein synthesis and that the community-level responses result from an interplay of matrix composition, matrix dissociation and mechanical interactions between cells. We further observed that the antibiotic-induced changes in biofilm architecture have substantial effects on biofilm population dynamics and community assembly by enabling invasion of biofilms by bacteriophages and intruder cells of different species. These mechanistic causes and ecological consequences of biofilm exposure to antibiotics are an important step towards understanding collective bacterial responses to environmental changes, with implications for the effects of antimicrobial therapy on the ecological succession of biofilm communities.
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Affiliation(s)
| | - Raimo Hartmann
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Martin Lempp
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Lucia Vidakovic
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Boya Song
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Hannah Jeckel
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Philipps-Universität Marburg, Marburg, Germany
| | - Kai M Thormann
- Institut für Mikrobiologie und Molekularbiologie, Justus-Liebig-Universität Gießen, Gießen, Germany
| | - Fitnat H Yildiz
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Jörn Dunkel
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Hannes Link
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Synmikro Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg, Germany
| | - Carey D Nadell
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Biological Sciences, Dartmouth College, Hanover, USA
| | - Knut Drescher
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
- Department of Physics, Philipps-Universität Marburg, Marburg, Germany.
- Synmikro Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg, Germany.
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74
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Tam A, Green JEF, Balasuriya S, Tek EL, Gardner JM, Sundstrom JF, Jiranek V, Binder BJ. A thin-film extensional flow model for biofilm expansion by sliding motility. Proc Math Phys Eng Sci 2019; 475:20190175. [PMID: 31611714 PMCID: PMC6784397 DOI: 10.1098/rspa.2019.0175] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 07/22/2019] [Indexed: 12/17/2022] Open
Abstract
In the presence of glycoproteins, bacterial and yeast biofilms are hypothesized to expand by sliding motility. This involves a sheet of cells spreading as a unit, facilitated by cell proliferation and weak adhesion to the substratum. In this paper, we derive an extensional flow model for biofilm expansion by sliding motility to test this hypothesis. We model the biofilm as a two-phase (living cells and an extracellular matrix) viscous fluid mixture, and model nutrient depletion and uptake from the substratum. Applying the thin-film approximation simplifies the model, and reduces it to one-dimensional axisymmetric form. Comparison with Saccharomyces cerevisiae mat formation experiments reveals good agreement between experimental expansion speed and numerical solutions to the model withO ( 1 ) parameters estimated from experiments. This confirms that sliding motility is a possible mechanism for yeast biofilm expansion. Having established the biological relevance of the model, we then demonstrate how the model parameters affect expansion speed, enabling us to predict biofilm expansion for different experimental conditions. Finally, we show that our model can explain the ridge formation observed in some biofilms. This is especially true if surface tension is low, as hypothesized for sliding motility.
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Affiliation(s)
- Alexander Tam
- School of Mathematical Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - J. Edward F. Green
- School of Mathematical Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Sanjeeva Balasuriya
- School of Mathematical Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Ee Lin Tek
- Department of Wine and Food Science, Waite Campus, University of Adelaide, Urrbrae, South Australia 5064, Australia
| | - Jennifer M. Gardner
- Department of Wine and Food Science, Waite Campus, University of Adelaide, Urrbrae, South Australia 5064, Australia
| | - Joanna F. Sundstrom
- Department of Wine and Food Science, Waite Campus, University of Adelaide, Urrbrae, South Australia 5064, Australia
| | - Vladimir Jiranek
- Department of Wine and Food Science, Waite Campus, University of Adelaide, Urrbrae, South Australia 5064, Australia
| | - Benjamin J. Binder
- School of Mathematical Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
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75
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Wickramasinghe NN, Ravensdale JT, Coorey R, Dykes GA, Scott Chandry P. In situ characterisation of biofilms formed by psychrotrophic meat spoilage pseudomonads. BIOFOULING 2019; 35:840-855. [PMID: 31558055 DOI: 10.1080/08927014.2019.1669021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Psychrotrophic Pseudomonas species form biofilms on meat during refrigerated and temperature abuse conditions. Biofilm growth leads to slime formation on meat which is a key organoleptic degradation characteristic. Limited research has been undertaken characterising biofilms grown on meat during chilled aerobic storage. In this work, biofilms formed by two key meat spoilage organisms, Pseudomonas fragi and Pseudomonas lundensis were studied in situ using five strains from each species. Biofilm structures were studied using confocal microscope images, cellular arrangement, cell counts and biomass quantifications. This work demonstrated that highly dense, compact biofilms are a characteristic of P. fragi strains. P. lundensis formed biofilms with loosely arranged cells. The cells in P. fragi biofilm appear to be vertically oriented whereas this characteristic was absent in P. lundensis biofilms formed under identical conditions. Despite the continued access to nutrients, biofilms formed on meat by proteolytic Pseudomonas species dispersed after a population maximum was reached.
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Affiliation(s)
- Nirmani N Wickramasinghe
- School of Public Health, Curtin University, Bentley, Western Australia, Australia
- Agriculture and Food, CSIRO, Werribee, Victoria, Australia
| | - Joshua T Ravensdale
- School of Public Health, Curtin University, Bentley, Western Australia, Australia
| | - Ranil Coorey
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Gary A Dykes
- School of Public Health, Curtin University, Bentley, Western Australia, Australia
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76
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Paul R, Ghosh T, Tang T, Kumar A. Rivalry in Bacillus subtilis colonies: enemy or family? SOFT MATTER 2019; 15:5400-5411. [PMID: 31172158 DOI: 10.1039/c9sm00794f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Two colonies of Bacillus subtilis of identical strains growing adjacent to each other on an agar plate exhibit two distinct types of interactions: they either merge as they grow or demarcation occurs leading to formation of a line of demarcation at the colony fronts. The nature of this interaction depends on the agar concentration in the growth medium and the initial separation between the colonies. When the agar concentration was 0.67% or lower, the two sibling colonies were found to always merge. At 1% or higher concentrations, the colonies formed a demarcation line only when their initial separation was 20 mm or higher. Interactions of a colony with solid structures and liquid drops have indicated that biochemical factors rather than the presence of physical obstacles are responsible for the demarcation line formation. A reaction diffusion model has been formulated to predict if two sibling colonies will form a demarcation line under given agar concentration and initial separation. The model prediction agrees well with experimental findings and generates a dimensionless phase diagram containing merging and demarcation regimes. The phase diagram is in terms of a dimensionless initial separation, d[combining macron], and a dimensionless diffusion coefficient, D[combining macron], of the colonies. The phase boundary between the two interaction regimes can be described by a power law relation between d[combining macron] and D[combining macron].
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Affiliation(s)
- Rajorshi Paul
- Department of Mechanical Engineering, University of Alberta, Edmonton, Canada
| | - Tanushree Ghosh
- Department of Mechanical Engineering, University of Alberta, Edmonton, Canada
| | - Tian Tang
- Department of Mechanical Engineering, University of Alberta, Edmonton, Canada
| | - Aloke Kumar
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India.
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Abstract
The cytoplasm of bacterial cells is a highly crowded cellular compartment that possesses considerable osmotic potential. As a result, and owing to the semipermeable nature of the cytoplasmic membrane and the semielastic properties of the cell wall, osmotically driven water influx will generate turgor, a hydrostatic pressure considered critical for growth and viability. Both increases and decreases in the external osmolarity inevitably trigger water fluxes across the cytoplasmic membrane, thus impinging on the degree of cellular hydration, molecular crowding, magnitude of turgor, and cellular integrity. Here, we assess mechanisms that permit the perception of osmotic stress by bacterial cells and provide an overview of the systems that allow them to genetically and physiologically cope with this ubiquitous environmental cue. We highlight recent developments implicating the secondary messenger c-di-AMP in cellular adjustment to osmotic stress and the role of osmotic forces in the life of bacteria-assembled in biofilms.
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Affiliation(s)
- Erhard Bremer
- Laboratory for Microbiology, Department of Biology; and Center for Synthetic Microbiology, Philipps-Universität Marburg, 35043 Marburg, Germany;
| | - Reinhard Krämer
- Institute of Biochemistry, University of Cologne, 50674 Cologne, Germany;
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78
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Graf AC, Leonard A, Schäuble M, Rieckmann LM, Hoyer J, Maass S, Lalk M, Becher D, Pané-Farré J, Riedel K. Virulence Factors Produced by Staphylococcus aureus Biofilms Have a Moonlighting Function Contributing to Biofilm Integrity. Mol Cell Proteomics 2019; 18:1036-1053. [PMID: 30850421 PMCID: PMC6553939 DOI: 10.1074/mcp.ra118.001120] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 02/19/2019] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus is the causative agent of various biofilm-associated infections in humans causing major healthcare problems worldwide. This type of infection is inherently difficult to treat because of a reduced metabolic activity of biofilm-embedded cells and the protective nature of a surrounding extracellular matrix (ECM). However, little is known about S. aureus biofilm physiology and the proteinaceous composition of the ECM. Thus, we cultivated S. aureus biofilms in a flow system and comprehensively profiled intracellular and extracellular (ECM and flow-through (FT)) biofilm proteomes, as well as the extracellular metabolome compared with planktonic cultures. Our analyses revealed the expression of many pathogenicity factors within S. aureus biofilms as indicated by a high abundance of capsule biosynthesis proteins along with various secreted virulence factors, including hemolysins, leukotoxins, and lipases as a part of the ECM. The activity of ECM virulence factors was confirmed in a hemolysis assay and a Galleria mellonella pathogenicity model. In addition, we uncovered a so far unacknowledged moonlighting function of secreted virulence factors and ribosomal proteins trapped in the ECM: namely their contribution to biofilm integrity. Mechanistically, it was revealed that this stabilizing effect is mediated by the strong positive charge of alkaline virulence factors and ribosomal proteins in an acidic ECM environment, which is caused by the release of fermentation products like formate, lactate, and acetate because of oxygen limitation in biofilms. The strong positive charge of these proteins most likely mediates electrostatic interactions with anionic cell surface components, eDNA, and anionic metabolites. In consequence, this leads to strong cell aggregation and biofilm stabilization. Collectively, our study identified a new molecular mechanism during S. aureus biofilm formation and thus significantly widens the understanding of biofilm-associated S. aureus infections - an essential prerequisite for the development of novel antimicrobial therapies.
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Affiliation(s)
- Alexander C Graf
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology
| | - Anne Leonard
- §Institute of Biochemistry, Department of Cellular Biochemistry and Metabolomics
| | - Manuel Schäuble
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology
| | - Lisa M Rieckmann
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology
| | - Juliane Hoyer
- ¶Institute of Microbiology, Department of Microbial Proteomics; University of Greifswald, Germany
| | - Sandra Maass
- ¶Institute of Microbiology, Department of Microbial Proteomics; University of Greifswald, Germany
| | - Michael Lalk
- §Institute of Biochemistry, Department of Cellular Biochemistry and Metabolomics
| | - Dörte Becher
- ¶Institute of Microbiology, Department of Microbial Proteomics; University of Greifswald, Germany
| | - Jan Pané-Farré
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology
| | - Katharina Riedel
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology;
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79
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Zeng Z, Zhan W, Wang W, Wang P, Tang K, Wang X. Biofilm formation in Pseudoalteromonas lipolytica is related to IS5-like insertions in the capsular polysaccharide operon. FEMS Microbiol Ecol 2019; 95:5488432. [PMID: 31077283 DOI: 10.1093/femsec/fiz065] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 05/10/2019] [Indexed: 11/14/2022] Open
Abstract
Bacterial capsular polysaccharides (CPSs) participate in environmental adaptation in diverse bacteria species. However, the role and regulation of CPS production in marine bacteria have remained largely unexplored. We previously reported that both wrinkled and translucent Pseudoalteromonas lipolytica variants with altered polysaccharide production were generated in pellicle biofilm-associated cells. In this study, we observed that translucent variants were generated at a rate of ∼20% in colony biofilms of P. lipolytica cultured on HSLB agar plates for 12 days. The DNA sequencing results revealed that nearly 90% of these variants had an IS5-like element inserted within the coding or promoter regions of nine genes in the cps operon. In contrast, IS5 insertion into the cps operon was not detected in planktonic cells. Furthermore, we demonstrated that the IS5 insertion event inactivated CPS production, which leads to a translucent colony morphology. The CPS-deficient variants showed an increased ability to form attached biofilms but exhibited reduced resistance to sublethal concentrations of antibiotics. Moreover, deleting the DNA repair gene recA significantly decreased the frequency of occurrence of CPS-deficient variants during biofilm formation. Thus, IS insertion into the cps operon is an important mechanism for the production of genetic variants during biofilm formation of marine bacteria.
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Affiliation(s)
- Zhenshun Zeng
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Waner Zhan
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weiquan Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Pengxia Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Kaihao Tang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.,University of Chinese Academy of Sciences, Beijing 100049, China
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80
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Ma Y, Li J, Si Y, Huang K, Nitin N, Sun G. Rechargeable Antibacterial N-Halamine Films with Antifouling Function for Food Packaging Applications. ACS APPLIED MATERIALS & INTERFACES 2019; 11:17814-17822. [PMID: 31022343 DOI: 10.1021/acsami.9b03464] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Pathogenic microbial contamination from microbial adhesion and subsequent formation of the biofilm on surfaces of plastic food packaging materials, especially with robust resistance to antimicrobial agents, is a major reason for the outbreak of foodborne infections. Conventional strategies in controlling the contaminations are significantly limited either by biofouling or by the irreversible consumption of antimicrobial agents. Herein, we report a robust methodology to create rechargeable biocidal poly(vinyl alcohol- co-ethylene) films (SBMA@HAF films) with antifouling function via chemically incorporating both N-halamine (HAF) and zwitterionic moieties [[2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA)]. The promise of the design exhibits three features to defeat bacterial contaminations: (i) zwitterionic moieties can effectively reduce bacterial attachment onto the films, (ii) N-halamine with robust rechargeable biocidal activity can rapidly kill any attached bacteria, and (iii) any inactivated bacterial debris can be easily released to avoid biofilm formation due to the superhydrophilicity of the zwitterions. The resulting SBMA@HAF films exhibit integrated properties of high transparency, robust mechanical property, great hydrophilicity, ease of chlorine recharging (>250 ppm), long-term stability, high biocidal efficacy (>99.9999% via contact killing), and promising antifouling functions, which enable the SBMA@HAF films to serve as a biocidal material in food packaging applications.
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81
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Srinivasan S, Kaplan CN, Mahadevan L. A multiphase theory for spreading microbial swarms and films. eLife 2019; 8:42697. [PMID: 31038122 PMCID: PMC6491038 DOI: 10.7554/elife.42697] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 03/14/2019] [Indexed: 11/30/2022] Open
Abstract
Bacterial swarming and biofilm formation are collective multicellular phenomena through which diverse microbial species colonize and spread over water-permeable tissue. During both modes of surface translocation, fluid uptake and transport play a key role in shaping the overall morphology and spreading dynamics. Here we develop a generalized two-phase thin-film model that couples bacterial growth, extracellular matrix swelling, fluid flow, and nutrient transport to describe the expansion of both highly motile bacterial swarms, and sessile bacterial biofilms. We show that swarm expansion corresponds to steady-state solutions in a nutrient-rich, capillarity dominated regime. In contrast, biofilm colony growth is described by transient solutions associated with a nutrient-limited, extracellular polymer stress driven limit. We apply our unified framework to explain a range of recent experimental observations of steady and unsteady expansion of microbial swarms and biofilms. Our results demonstrate how the physics of flow and transport in slender geometries serve to constrain biological organization in microbial communities. Bacteria can grow and thrive in many different environments. Although we usually think of bacteria as single-celled organisms, they are not always solitary; they can also form groups containing large numbers of individuals. These aggregates work together as one super-colony, allowing the bacteria to feed and protect themselves more efficiently than they could as isolated cells. These colonies move and grow in characteristic patterns as they respond to their environment. They can form swarms, like insects, or biofilms, which are thin, flat structures containing both cells and a film-like substance that the cells secrete. Availability of food and water influences the way colonies spread; however, since movement and growth are accompanied by mechanical forces, physical constraints are also important. These include the ability of the bacteria to change the water balance and their local mechanical environment, and the forces they create as they grow and move. Previous research has used a variety of experimental and theoretical approaches to explain the dynamics of bacterial swarms and biofilms as separate phenomena. However, while they do differ biologically, they also share many physical characteristics. Srinivasan et al. wanted to exploit these similarities, and use them to predict the growth and shape of biofilms and bacterial swarms under different conditions. To do this, a unified mathematical model for the growth of both swarms and biofilms was created. The model accounted for various factors, such as the transport of nutrients into the colony, the movement of water between the colony and the surface on which it grew, and mechanical changes in the environment (e.g. swelling/softening). The theoretical results were then compared with results from experimental measurements of different bacterial aggregates grown on a soft, hydrated gel. For both swarms and biofilms, the model correctly predicted how fast the colony expanded overall, as well as the shape and location of actively growing regions. Biofilms and other bacterial aggregates can cause diseases and increase inflammation in tissues, and also hinder industrial processes by damage to submerged surfaces, such as ships and waterpipes. The results described here may open up new approaches to restrict the spreading of bacterial aggregates by focusing on their physical constraints.
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Affiliation(s)
- Siddarth Srinivasan
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, United States
| | - C Nadir Kaplan
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, United States.,Kavli Institute for Bionano Science and Technology, Harvard University, Cambridge, United States
| | - L Mahadevan
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, United States.,Kavli Institute for Bionano Science and Technology, Harvard University, Cambridge, United States.,Department of Physics, Harvard University, Cambridge, United States.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, United States
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82
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Bettenworth V, Steinfeld B, Duin H, Petersen K, Streit WR, Bischofs I, Becker A. Phenotypic Heterogeneity in Bacterial Quorum Sensing Systems. J Mol Biol 2019; 431:4530-4546. [PMID: 31051177 DOI: 10.1016/j.jmb.2019.04.036] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 04/19/2019] [Accepted: 04/22/2019] [Indexed: 12/11/2022]
Abstract
Quorum sensing is usually thought of as a collective behavior in which all members of a population partake. However, over the last decade, several reports of phenotypic heterogeneity in quorum sensing-related gene expression have been put forward, thus challenging this view. In the respective systems, cells of isogenic populations did not contribute equally to autoinducer production or target gene activation, and in some cases, the fraction of contributing cells was modulated by environmental factors. Here, we look into potential origins of these incidences and into how initial cell-to-cell variations might be amplified to establish distinct phenotypic heterogeneity. We furthermore discuss potential functions heterogeneity in bacterial quorum sensing systems could serve: as a preparation for environmental fluctuations (bet hedging), as a more cost-effective way of producing public goods (division of labor), as a loophole for genotypic cooperators when faced with non-contributing mutants (cheat protection), or simply as a means to fine-tune the output of the population as a whole (output modulation). We illustrate certain aspects of these recent developments with the model organisms Sinorhizobium meliloti, Sinorhizobium fredii and Bacillus subtilis, which possess quorum sensing systems of different complexity, but all show phenotypic heterogeneity therein.
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Affiliation(s)
- Vera Bettenworth
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, 35043 Marburg, Germany; Faculty of Biology, Philipps-Universität Marburg, 35043 Marburg, Germany.
| | - Benedikt Steinfeld
- BioQuant Center of the University of Heidelberg, 69120 Heidelberg, Germany; Center for Molecular Biology (ZMBH), University of Heidelberg, 69120 Heidelberg, Germany; Max-Planck-Institute for Terrestrial Microbiology, 35043 Marburg, Germany.
| | - Hilke Duin
- Department of Microbiology and Biotechnology, University of Hamburg, 22609 Hamburg, Germany.
| | - Katrin Petersen
- Department of Microbiology and Biotechnology, University of Hamburg, 22609 Hamburg, Germany.
| | - Wolfgang R Streit
- Department of Microbiology and Biotechnology, University of Hamburg, 22609 Hamburg, Germany.
| | - Ilka Bischofs
- BioQuant Center of the University of Heidelberg, 69120 Heidelberg, Germany; Center for Molecular Biology (ZMBH), University of Heidelberg, 69120 Heidelberg, Germany; Max-Planck-Institute for Terrestrial Microbiology, 35043 Marburg, Germany.
| | - Anke Becker
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, 35043 Marburg, Germany; Faculty of Biology, Philipps-Universität Marburg, 35043 Marburg, Germany.
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83
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Kayser J, Schreck CF, Yu Q, Gralka M, Hallatschek O. Emergence of evolutionary driving forces in pattern-forming microbial populations. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0106. [PMID: 29632260 DOI: 10.1098/rstb.2017.0106] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2018] [Indexed: 12/12/2022] Open
Abstract
Evolutionary dynamics are controlled by a number of driving forces, such as natural selection, random genetic drift and dispersal. In this perspective article, we aim to emphasize that these forces act at the population level, and that it is a challenge to understand how they emerge from the stochastic and deterministic behaviour of individual cells. Even the most basic steric interactions between neighbouring cells can couple evolutionary outcomes of otherwise unrelated individuals, thereby weakening natural selection and enhancing random genetic drift. Using microbial examples of varying degrees of complexity, we demonstrate how strongly cell-cell interactions influence evolutionary dynamics, especially in pattern-forming systems. As pattern formation itself is subject to evolution, we propose to study the feedback between pattern formation and evolutionary dynamics, which could be key to predicting and potentially steering evolutionary processes. Such an effort requires extending the systems biology approach from the cellular to the population scale.This article is part of the theme issue 'Self-organization in cell biology'.
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Affiliation(s)
- Jona Kayser
- Department of Physics, University of California, Berkeley, CA 94720, USA.,Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - Carl F Schreck
- Department of Physics, University of California, Berkeley, CA 94720, USA.,Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - QinQin Yu
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Matti Gralka
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Oskar Hallatschek
- Department of Physics, University of California, Berkeley, CA 94720, USA .,Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
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84
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Yan J, Fei C, Mao S, Moreau A, Wingreen NS, Košmrlj A, Stone HA, Bassler BL. Mechanical instability and interfacial energy drive biofilm morphogenesis. eLife 2019; 8:43920. [PMID: 30848725 PMCID: PMC6453567 DOI: 10.7554/elife.43920] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 03/06/2019] [Indexed: 11/17/2022] Open
Abstract
Surface-attached bacterial communities called biofilms display a diversity of morphologies. Although structural and regulatory components required for biofilm formation are known, it is not understood how these essential constituents promote biofilm surface morphology. Here, using Vibrio cholerae as our model system, we combine mechanical measurements, theory and simulation, quantitative image analyses, surface energy characterizations, and mutagenesis to show that mechanical instabilities, including wrinkling and delamination, underlie the morphogenesis program of growing biofilms. We also identify interfacial energy as a key driving force for mechanomorphogenesis because it dictates the generation of new and the annihilation of existing interfaces. Finally, we discover feedback between mechanomorphogenesis and biofilm expansion, which shapes the overall biofilm contour. The morphogenesis principles that we discover in bacterial biofilms, which rely on mechanical instabilities and interfacial energies, should be generally applicable to morphogenesis processes in tissues in higher organisms. Engineers have long studied how mechanical instabilities cause patterns to form in inanimate materials, and recently more attention has been given to how such forces affect biological systems. For example, stresses can build up within a tissue if one layer grows faster than an adjacent layer. The tissue can release this stress by wrinkling, folding or creasing. Though ancient and single-celled, bacteria can also develop spectacular patterns when they exist in the lifestyle known as a biofilm: a community of cells adhered to a surface. But do mechanical instabilities drive the patterns seen in biofilms? To investigate, Yan, Fei, Mao et al. grew biofilms of the bacterium called Vibrio cholerae – which causes the disease cholera – on solid, non-growing ‘substrates’. This work revealed that as the biofilms grow, their expansion is constrained by the substrate, and this situation generates mechanical stresses. To release the stresses, the biofilm initially folds to form wrinkles. Later, as the biofilm expands further, small parts of it detach from the substrate to form blisters. The same forces that keep water droplets spherical (known as interfacial forces) dictate how the blisters evolve, interact, and eventually shape the expanding biofilm. Using these principles, Yan et al. could engineer the biofilm into desired shapes. Collectively, the results presented by Yan et al. connect the shape of the biofilm surface with its material properties, in particular its stiffness. Understanding this relationship could help researchers to develop new ways to remove harmful biofilms, such as those that cause disease or that damage underwater structures. The stiffness of biofilms is already known to affect how well bacteria can resist antibiotics. Future studies could look for new genes or compounds that change the material properties of a biofilm, thereby altering the biofilm surface.
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Affiliation(s)
- Jing Yan
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, United States.,Department of Molecular Biology, Princeton University, Princeton, United States
| | - Chenyi Fei
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Sheng Mao
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, United States
| | - Alexis Moreau
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, United States
| | - Ned S Wingreen
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Andrej Košmrlj
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, United States
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, United States
| | - Bonnie L Bassler
- Department of Molecular Biology, Princeton University, Princeton, United States.,The Howard Hughes Medical Institute, Chevy Chase, United States
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85
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86
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Kayser J, Schreck CF, Gralka M, Fusco D, Hallatschek O. Collective motion conceals fitness differences in crowded cellular populations. Nat Ecol Evol 2018; 3:125-134. [PMID: 30510177 PMCID: PMC6309230 DOI: 10.1038/s41559-018-0734-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 10/23/2018] [Indexed: 12/15/2022]
Abstract
Many cellular populations are tightly-packed, such as microbial colonies and biofilms, or tissues and tumors in multicellular organisms. Movement of one cell in those crowded assemblages requires motion of others, so that cell displacements are correlated over many cell diameters. Whenever movement is important for survival or growth, these correlated rearrangements could couple the evolutionary fate of different lineages. Yet, little is known about the interplay between mechanical forces and evolution in dense cellular populations. Here, by tracking slower-growing clones at the expanding edge of yeast colonies, we show that the collective motion of cells prevents costly mutations from being weeded out rapidly. Joint pushing by neighboring cells generates correlated movements that suppress the differential displacements required for selection to act. This mechanical screening of fitness differences allows slower-growing mutants to leave more descendants than expected under non-mechanical models, thereby increasing their chance for evolutionary rescue. Our work suggests that, in crowded populations, cells cooperate with surrounding neighbors through inevitable mechanical interactions. This effect has to be considered when predicting evolutionary outcomes, such as the emergence of drug resistance or cancer evolution.
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Affiliation(s)
- Jona Kayser
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA.,Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Carl F Schreck
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA.,Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Matti Gralka
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA
| | - Diana Fusco
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA.,Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Oskar Hallatschek
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA. .,Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA.
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87
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Liu S, Cao S, Guo J, Luo L, Zhou Y, Lin C, Shi J, Fan C, Lv M, Wang L. Graphene oxide-silver nanocomposites modulate biofilm formation and extracellular polymeric substance (EPS) production. NANOSCALE 2018; 10:19603-19611. [PMID: 30325394 DOI: 10.1039/c8nr04064h] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Biofilms with positive and negative actions ubiquitously affect medical infections, environmental remediation and industrial processes. However, it remains challenging to control the growth of harmful biofilms as well as to exploit the use of beneficial biofilms. Here we investigated the effect of an antibacterial graphene oxide-silver nanoparticles (GO-AgNPs) composite on Pseudomonas aeruginosa biofilm formation. We found that GO-AgNPs prevented biofilm formation in a dose-dependent manner, with a threshold of 15 μg mL-1. Interestingly, the bacterial biomass significantly decreased, but extracellular polymeric substance (EPS) production remarkably increased in mature biofilms treated with GO-AgNPs of an appropriate concentration, suggesting that GO-AgNPs effectively modulate biofilm development and structure. Moreover, we established that GO-AgNPs caused bacterial death via both physical damage and oxidative stress, showing the synergic action of GO and AgNPs. These findings facilitate the use of graphene-based nanocomposites for greener antibiotic applications.
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Affiliation(s)
- Shima Liu
- College of Sciences, Shanghai University, Shanghai 200444, China.
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88
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Yan J, Moreau A, Khodaparast S, Perazzo A, Feng J, Fei C, Mao S, Mukherjee S, Košmrlj A, Wingreen NS, Bassler BL, Stone HA. Bacterial Biofilm Material Properties Enable Removal and Transfer by Capillary Peeling. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1804153. [PMID: 30368924 PMCID: PMC8865467 DOI: 10.1002/adma.201804153] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/30/2018] [Indexed: 05/22/2023]
Abstract
Biofilms, surface-attached communities of bacterial cells, are a concern in health and in industrial operations because of persistent infections, clogging of flows, and surface fouling. Extracellular matrices provide mechanical protection to biofilm-dwelling cells as well as protection from chemical insults, including antibiotics. Understanding how biofilm material properties arise from constituent matrix components and how these properties change in different environments is crucial for designing biofilm removal strategies. Here, using rheological characterization and surface analyses of Vibrio cholerae biofilms, it is discovered how extracellular polysaccharides, proteins, and cells function together to define biofilm mechanical and interfacial properties. Using insight gained from our measurements, a facile capillary peeling technology is developed to remove biofilms from surfaces or to transfer intact biofilms from one surface to another. It is shown that the findings are applicable to other biofilm-forming bacterial species and to multiple surfaces. Thus, the technology and the understanding that have been developed could potentially be employed to characterize and/or treat biofilm-related infections and industrial biofouling problems.
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Affiliation(s)
- Jing Yan
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Alexis Moreau
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Sepideh Khodaparast
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Antonio Perazzo
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Jie Feng
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Chenyi Fei
- Department of Molecular Biology, Princeton University, 329 Lewis Thomas Laboratory, Princeton, NJ, 08544, USA
| | - Sheng Mao
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Sampriti Mukherjee
- Department of Molecular Biology, Princeton University, 329 Lewis Thomas Laboratory, Princeton, NJ, 08544, USA
| | - Andrej Košmrlj
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
| | - Ned S Wingreen
- Department of Molecular Biology, Princeton University, 329 Lewis Thomas Laboratory, Princeton, NJ, 08544, USA
| | - Bonnie L Bassler
- Department of Molecular Biology, Princeton University, 329 Lewis Thomas Laboratory, Princeton, NJ, 08544, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, 20815, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, D328 E-Quad, Olden St., Princeton, NJ, 08544, USA
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89
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Tiwari V, Meena K, Tiwari M. Differential anti-microbial secondary metabolites in different ESKAPE pathogens explain their adaptation in the hospital setup. INFECTION GENETICS AND EVOLUTION 2018; 66:57-65. [PMID: 30227225 DOI: 10.1016/j.meegid.2018.09.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/24/2018] [Accepted: 09/14/2018] [Indexed: 01/22/2023]
Abstract
Nosocomial infections are caused by ESKAPE (E. faecium, S. aureus, K. pneumoniae, A. baumannii, P. aeruginosa, and E. cloacae) pathogens, and their co-existence is associated with their ability to survive in the hospital setup. They may produce molecules, which helps in the better survival of one ESKAPE pathogens over other. We have identified all secondary metabolite gene clusters in six ESKAPE pathogens and predicted antimicrobial and anti-biofilm properties of their product secondary metabolites. To validate our model, we have taken the secondary metabolites of ESKAPE pathogens and studied their interaction with diguanylate cyclase (involved in quorum sensing) and biofilm-associated protein (involved in biofilm formation) of Acinetobacter baumannii. Results suggest the presence of differential secondary metabolites in all ESKAPE pathogens with only three common non-antimicrobial secondary metabolites. Out of twenty-three antimicrobial secondary metabolites, TP-1161, nosiheptide and meilingmycin, showed the best antimicrobial activity and nineteen showed high anti-biofilm activity. Interaction study showed that secondary metabolites produced by other ESKAPE pathogens (non-Acinetobacter) have very good interaction with diguanylate cyclase and biofilm-associated protein of A. baumannii. This concludes that better survival of these ESKAPE pathogens in hospital setup can be correlated with differential production of antimicrobial secondary metabolites. The present study also investigates the molecular mechanism of the competition of different pathogens living in similar hospital setup (similar habitat). Therefore, the present study will initiate research that might lead to the discovery of antibiotics from one ESKAPE pathogen that controls the infection of other ESKAPE pathogens or other pathogens.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, -305817, India.
| | - Kiran Meena
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, -305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, -305817, India
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90
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A single mutation in rapP induces cheating to prevent cheating in Bacillus subtilis by minimizing public good production. Commun Biol 2018; 1:133. [PMID: 30272012 PMCID: PMC6123732 DOI: 10.1038/s42003-018-0136-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 08/10/2018] [Indexed: 12/30/2022] Open
Abstract
Cooperation is beneficial to group behaviors like multicellularity, but is vulnerable to exploitation by cheaters. Here we analyze mechanisms that protect against exploitation of extracellular surfactin in swarms of Bacillus subtilis. Unexpectedly, the reference strain NCIB 3610 displays inherent resistance to surfactin-non-producing cheaters, while a different wild isolate is susceptible. We trace this interstrain difference down to a single amino acid change in the plasmid-borne regulator RapP, which is necessary and sufficient for cheater mitigation. This allele, prevalent in many Bacillus species, optimizes transcription of the surfactin operon to the minimum needed for full cooperation. When combined with a strain lacking rapP, NCIB 3610 acts as a cheater itself—except it does not harm the population at high proportions since it still produces enough surfactin. This strategy of minimal production is thus a doubly advantageous mechanism to limit exploitation of public goods, and is readily evolved from existing regulatory networks. Lyons and Kolter describe a single-point mutation in the plasmid-borne gene rapP of Bacillus subtilis that optimizes surfactin transcription to express the minimum required for cooperation. The decrease in the production of this public good significantly prevented the exploitation of cooperative traits by cheaters.
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91
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Beroz F, Yan J, Sabass B, Stone HA, Bassler BL, Wingreen NS, Meir Y. Verticalization of bacterial biofilms. NATURE PHYSICS 2018; 14:954-960. [PMID: 30906420 PMCID: PMC6426328 DOI: 10.1038/s41567-018-0170-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 05/11/2018] [Indexed: 05/18/2023]
Abstract
Biofilms are communities of bacteria adhered to surfaces. Recently, biofilms of rod-shaped bacteria were observed at single-cell resolution and shown to develop from a disordered, two-dimensional layer of founder cells into a three-dimensional structure with a vertically-aligned core. Here, we elucidate the physical mechanism underpinning this transition using a combination of agent-based and continuum modeling. We find that verticalization proceeds through a series of localized mechanical instabilities on the cellular scale. For short cells, these instabilities are primarily triggered by cell division, whereas long cells are more likely to be peeled off the surface by nearby vertical cells, creating an "inverse domino effect". The interplay between cell growth and cell verticalization gives rise to an exotic mechanical state in which the effective surface pressure becomes constant throughout the growing core of the biofilm surface layer. This dynamical isobaricity determines the expansion speed of a biofilm cluster and thereby governs how cells access the third dimension. In particular, theory predicts that a longer average cell length yields more rapidly expanding, flatter biofilms. We experimentally show that such changes in biofilm development occur by exploiting chemicals that modulate cell length.
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Affiliation(s)
- Farzan Beroz
- Joseph Henry Laboratories of Physics, Princeton University, Princeton NJ 08544, USA
| | - Jing Yan
- Department of Mechanical and Aerospace Engineering, Princeton University, NJ 08544, USA
| | - Benedikt Sabass
- Department of Mechanical and Aerospace Engineering, Princeton University, NJ 08544, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, NJ 08544, USA
| | - Bonnie L Bassler
- Department of Molecular Biology, Princeton University, Princeton NJ 08544, USA
| | - Ned S Wingreen
- Department of Molecular Biology, Princeton University, Princeton NJ 08544, USA
| | - Yigal Meir
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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92
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Van der Henst C, Vanhove AS, Drebes Dörr NC, Stutzmann S, Stoudmann C, Clerc S, Scrignari T, Maclachlan C, Knott G, Blokesch M. Molecular insights into Vibrio cholerae's intra-amoebal host-pathogen interactions. Nat Commun 2018; 9:3460. [PMID: 30150745 PMCID: PMC6110790 DOI: 10.1038/s41467-018-05976-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 08/07/2018] [Indexed: 01/03/2023] Open
Abstract
Vibrio cholerae, which causes the diarrheal disease cholera, is a species of bacteria commonly found in aquatic habitats. Within such environments, the bacterium must defend itself against predatory protozoan grazers. Amoebae are prominent grazers, with Acanthamoeba castellanii being one of the best-studied aquatic amoebae. We previously showed that V. cholerae resists digestion by A. castellanii and establishes a replication niche within the host's osmoregulatory organelle. In this study, we decipher the molecular mechanisms involved in the maintenance of V. cholerae's intra-amoebal replication niche and its ultimate escape from the succumbed host. We demonstrate that minor virulence features important for disease in mammals, such as extracellular enzymes and flagellum-based motility, have a key role in the replication and transmission of V. cholerae in its aqueous environment. This work, therefore, describes new mechanisms that provide the pathogen with a fitness advantage in its primary habitat, which may have contributed to the emergence of these minor virulence factors in the species V. cholerae.
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Affiliation(s)
- Charles Van der Henst
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Station 19, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Audrey Sophie Vanhove
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Station 19, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Natália Carolina Drebes Dörr
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Station 19, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Sandrine Stutzmann
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Station 19, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Candice Stoudmann
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Station 19, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Stéphanie Clerc
- Bioelectron Microscopy Core Facility (BioEM), School of Life Sciences, Station 19, EPFL-SV-PTBIOEM, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Tiziana Scrignari
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Station 19, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Catherine Maclachlan
- Bioelectron Microscopy Core Facility (BioEM), School of Life Sciences, Station 19, EPFL-SV-PTBIOEM, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Graham Knott
- Bioelectron Microscopy Core Facility (BioEM), School of Life Sciences, Station 19, EPFL-SV-PTBIOEM, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Melanie Blokesch
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Station 19, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland.
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93
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Trinschek S, John K, Thiele U. Modelling of surfactant-driven front instabilities in spreading bacterial colonies. SOFT MATTER 2018; 14:4464-4476. [PMID: 29796452 DOI: 10.1039/c8sm00422f] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The spreading of bacterial colonies at solid-air interfaces is determined by the physico-chemical properties of the involved interfaces. The production of surfactant molecules by bacteria is a widespread strategy that allows the colony to efficiently expand over the substrate. On the one hand, surfactant molecules lower the surface tension of the colony, effectively increasing the wettability of the substrate, which facilitates spreading. On the other hand, gradients in the surface concentration of surfactant molecules result in Marangoni flows that drive spreading. These flows may cause an instability of the circular colony shape and the subsequent formation of fingers. In this work, we study the effect of bacterial surfactant production and substrate wettability on colony growth and shape within the framework of a hydrodynamic thin film model. We show that variations in the wettability and surfactant production are sufficient to reproduce four different types of colony growth, which have been described in the literature, namely, arrested and continuous spreading of circular colonies, slightly modulated front lines and the formation of pronounced fingers.
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Affiliation(s)
- Sarah Trinschek
- Institut für Theoretische Physik, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 9, 48149 Münster, Germany.
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94
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Majumdar S, Pal S. Information transmission in microbial and fungal communication: from classical to quantum. J Cell Commun Signal 2018; 12:491-502. [PMID: 29476316 PMCID: PMC5910326 DOI: 10.1007/s12079-018-0462-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 02/08/2018] [Indexed: 01/05/2023] Open
Abstract
Microbes have their own communication systems. Secretion and reception of chemical signaling molecules and ion-channels mediated electrical signaling mechanism are yet observed two special ways of information transmission in microbial community. In this article, we address the aspects of various crucial machineries which set the backbone of microbial cell-to-cell communication process such as quorum sensing mechanism (bacterial and fungal), quorum sensing regulated biofilm formation, gene expression, virulence, swarming, quorum quenching, role of noise in quorum sensing, mathematical models (therapy model, evolutionary model, molecular mechanism model and many more), synthetic bacterial communication, bacterial ion-channels, bacterial nanowires and electrical communication. In particular, we highlight bacterial collective behavior with classical and quantum mechanical approaches (including quantum information). Moreover, we shed a new light to introduce the concept of quantum synthetic biology and possible cellular quantum Turing test.
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Affiliation(s)
- Sarangam Majumdar
- Dipartimento di Ingegneria Scienze Informatiche e Matematica, Università degli Studi di L’ Aquila, Via Vetoio – Loc. Coppito, 67010 L’ Aquila, Italy
| | - Sukla Pal
- Theoretical Physics Division, Physical Research Laboratory, Navrangpura, Ahmedabad, Gujarat 380009 India
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95
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Abstract
Many bacteria use a cell-cell communication system called quorum sensing to coordinate population density-dependent changes in behavior. Quorum sensing involves production of and response to diffusible or secreted signals, which can vary substantially across different types of bacteria. In many species, quorum sensing modulates virulence functions and is important for pathogenesis. Over the past half-century, there has been a significant accumulation of knowledge of the molecular mechanisms, signal structures, gene regulons, and behavioral responses associated with quorum-sensing systems in diverse bacteria. More recent studies have focused on understanding quorum sensing in the context of bacterial sociality. Studies of the role of quorum sensing in cooperative and competitive microbial interactions have revealed how quorum sensing coordinates interactions both within a species and between species. Such studies of quorum sensing as a social behavior have relied on the development of "synthetic ecological" models that use nonclonal bacterial populations. In this review, we discuss some of these models and recent advances in understanding how microbes might interact with one another using quorum sensing. The knowledge gained from these lines of investigation has the potential to guide studies of microbial sociality in natural settings and the design of new medicines and therapies to treat bacterial infections.
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96
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Different activated methyl cycle pathways affect the pathogenicity of avian pathogenic Escherichia coli. Vet Microbiol 2017; 211:160-168. [DOI: 10.1016/j.vetmic.2017.10.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 10/19/2017] [Accepted: 10/19/2017] [Indexed: 01/20/2023]
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