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Chai L, Zaburdaev V, Kolter R. How bacteria actively use passive physics to make biofilms. Proc Natl Acad Sci U S A 2024; 121:e2403842121. [PMID: 39264745 DOI: 10.1073/pnas.2403842121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2024] Open
Abstract
Modern molecular microbiology elucidates the organizational principles of bacterial biofilms via detailed examination of the interplay between signaling and gene regulation. A complementary biophysical approach studies the mesoscopic dependencies at the cellular and multicellular levels with a distinct focus on intercellular forces and mechanical properties of whole biofilms. Here, motivated by recent advances in biofilm research and in other, seemingly unrelated fields of biology and physics, we propose a perspective that links the biofilm, a dynamic multicellular organism, with the physical processes occurring in the extracellular milieu. Using Bacillus subtilis as an illustrative model organism, we specifically demonstrate how such a rationale explains biofilm architecture, differentiation, communication, and stress responses such as desiccation tolerance, metabolism, and physiology across multiple scales-from matrix proteins and polysaccharides to macroscopic wrinkles and water-filled channels.
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Affiliation(s)
- Liraz Chai
- Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- Max Planck Queensland Centre, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Vasily Zaburdaev
- Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91058, Germany
- Max-Planck-Zentrum für Physik und Medizin, Erlangen 91058, Germany
| | - Roberto Kolter
- Department of Microbiology, Harvard Medical School, Boston, MA 02115
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2
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Gilhar O, Ben-Navi LR, Olender T, Aharoni A, Friedman J, Kolodkin-Gal I. Multigenerational inheritance drives symbiotic interactions of the bacterium Bacillus subtilis with its plant host. Microbiol Res 2024; 286:127814. [PMID: 38954993 DOI: 10.1016/j.micres.2024.127814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2024] [Revised: 06/04/2024] [Accepted: 06/18/2024] [Indexed: 07/04/2024]
Abstract
Bacillus subtilis is a beneficial bacterium that supports plant growth and protects plants from bacterial, fungal, and viral infections. Using a simplified system of B. subtilis and Arabidopsis thaliana interactions, we studied the fitness and transcriptome of bacteria detached from the root over generations of growth in LB medium. We found that bacteria previously associated with the root or exposed to its secretions had greater stress tolerance and were more competitive in root colonization than bacteria not previously exposed to the root. Furthermore, our transcriptome results provide evidence that plant secretions induce a microbial stress response and fundamentally alter signaling by the cyclic nucleotide c-di-AMP, a signature maintained by their descendants. The changes in cellular physiology due to exposure to plant exudates were multigenerational, as they allowed not only the bacterial cells that colonized a new plant but also their descendants to have an advance over naive competitors of the same species, while the overall plasticity of gene expression and rapid adaptation were maintained. These changes were hereditary but not permanent. Our work demonstrates a bacterial memory manifested by multigenerational reversible adaptation to plant hosts in the form of activation of the stressosome, which confers an advantage to symbiotic bacteria during competition.
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Affiliation(s)
- Omri Gilhar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel; Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | | | - Tsviya Olender
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Asaph Aharoni
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Jonathan Friedman
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Ilana Kolodkin-Gal
- Scojen Institute for Synthetic Biology, Reichman University, Herzliya, Israel.
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3
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Cometta S, Hutmacher DW, Chai L. In vitro models for studying implant-associated biofilms - A review from the perspective of bioengineering 3D microenvironments. Biomaterials 2024; 309:122578. [PMID: 38692146 DOI: 10.1016/j.biomaterials.2024.122578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 04/01/2024] [Accepted: 04/13/2024] [Indexed: 05/03/2024]
Abstract
Biofilm research has grown exponentially over the last decades, arguably due to their contribution to hospital acquired infections when they form on foreign body surfaces such as catheters and implants. Yet, translation of the knowledge acquired in the laboratory to the clinic has been slow and/or often it is not attempted by research teams to walk the talk of what is defined as 'bench to bedside'. We therefore reviewed the biofilm literature to better understand this gap. Our search revealed substantial development with respect to adapting surfaces and media used in models to mimic the clinical settings, however many of the in vitro models were too simplistic, often discounting the composition and properties of the host microenvironment and overlooking the biofilm-implant-host interactions. Failure to capture the physiological growth conditions of biofilms in vivo results in major differences between lab-grown- and clinically-relevant biofilms, particularly with respect to phenotypic profiles, virulence, and antimicrobial resistance, and they essentially impede bench-to-bedside translatability. In this review, we describe the complexity of the biological processes at the biofilm-implant-host interfaces, discuss the prerequisite for the development and characterization of biofilm models that better mimic the clinical scenario, and propose an interdisciplinary outlook of how to bioengineer biofilms in vitro by converging tissue engineering concepts and tools.
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Affiliation(s)
- Silvia Cometta
- Max Planck Queensland Centre, Queensland University of Technology, Brisbane, QLD 4000, Australia; Faculty of Engineering, School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia; Australian Research Council (ARC) Training Centre for Multiscale 3D Imaging, Modelling, and Manufacturing (M3D Innovation), Queensland University of Technology, Brisbane, QLD 4000, Australia.
| | - Dietmar W Hutmacher
- Max Planck Queensland Centre, Queensland University of Technology, Brisbane, QLD 4000, Australia; Faculty of Engineering, School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia; Australian Research Council (ARC) Training Centre for Multiscale 3D Imaging, Modelling, and Manufacturing (M3D Innovation), Queensland University of Technology, Brisbane, QLD 4000, Australia; Australian Research Council Training Centre for Cell and Tissue Engineering Technologies, Queensland University of Technology, Brisbane, QLD 4059, Australia.
| | - Liraz Chai
- Max Planck Queensland Centre, Queensland University of Technology, Brisbane, QLD 4000, Australia; The Hebrew University of Jerusalem, Institute of Chemistry, Jerusalem, 91904, Israel; The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel.
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4
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Chen G, Fanouraki G, Anandhi Rangarajan A, Winkelman BT, Winkelman JT, Waters CM, Mukherjee S. Combinatorial control of Pseudomonas aeruginosa biofilm development by quorum-sensing and nutrient-sensing regulators. mSystems 2024:e0037224. [PMID: 39140783 DOI: 10.1128/msystems.00372-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 06/23/2024] [Indexed: 08/15/2024] Open
Abstract
The human pathogen Pseudomonas aeruginosa, a leading cause of hospital-acquired infections, inhabits and forms sessile antibiotic-resistant communities called biofilms in a wide range of biotic and abiotic environments. In this study, we examined how two global sensory signaling pathways-the RhlR quorum-sensing system and the CbrA/CbrB nutritional adaptation system-intersect to control biofilm development. Previous work has shown that individually these two systems repress biofilm formation. Here, we used biofilm analyses, RNA-seq, and reporter assays to explore the combined effect of information flow through RhlR and CbrA on biofilm development. We find that the ΔrhlRΔcbrA double mutant exhibits a biofilm morphology and an associated transcriptional response distinct from wildtype and the parent ΔrhlR and ΔcbrA mutants indicating codominance of each signaling pathway. The ΔrhlRΔcbrA mutant gains suppressor mutations that allow biofilm expansion; these mutations map to the crc gene resulting in loss of function of the carbon catabolite repression protein Crc. Furthermore, the combined absence of RhlR and CbrA leads to a drastic reduction in the abundance of the Crc antagonist small RNA CrcZ. Thus, CrcZ acts as the molecular convergence point for quorum- and nutrient-sensing cues. We find that in the absence of antagonism by CrcZ, Crc promotes the expression of biofilm matrix components-Pel exopolysaccharide, and CupB and CupC fimbriae. Therefore, this study uncovers a regulatory link between nutritional adaption and quorum sensing with potential implications for anti-biofilm targeting strategies.IMPORTANCEBacteria often form multicellular communities encased in an extracytoplasmic matrix called biofilms. Biofilm development is controlled by various environmental stimuli that are decoded and converted into appropriate cellular responses. To understand how information from two distinct stimuli is integrated, we used biofilm formation in the human pathogen Pseudomonas aeruginosa as a model and studied the intersection of two global sensory signaling pathways-quorum sensing and nutritional adaptation. Global transcriptomics on biofilm cells and reporter assays suggest parallel regulation of biofilms by each pathway that converges on the abundance of a small RNA antagonist of the carbon catabolite repression protein, Crc. We find a new role of Crc as it modulates the expression of biofilm matrix components in response to the environment. These results expand our understanding of the genetic regulatory strategies that allow P. aeruginosa to successfully develop biofilm communities.
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Affiliation(s)
- Gong Chen
- Department of Molecular Genetics & Cell Biology, The University of Chicago, Chicago, Illinois, USA
| | - Georgia Fanouraki
- Department of Molecular Genetics & Cell Biology, The University of Chicago, Chicago, Illinois, USA
| | | | | | - Jared T Winkelman
- Department of Molecular Genetics & Cell Biology, The University of Chicago, Chicago, Illinois, USA
| | - Christopher M Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Sampriti Mukherjee
- Department of Molecular Genetics & Cell Biology, The University of Chicago, Chicago, Illinois, USA
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5
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Cate JD, Sullivan YZ, King MD. Inhibition of Microbial Growth and Biofilm Formation in Pure and Mixed Bacterial Samples. Microorganisms 2024; 12:1500. [PMID: 39065268 PMCID: PMC11278618 DOI: 10.3390/microorganisms12071500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 07/08/2024] [Accepted: 07/11/2024] [Indexed: 07/28/2024] Open
Abstract
Hydraulic fracturing, or fracking, requires large amounts of water to extract fossil fuel from rock formations. As a result of hydraulic fracturing, the briny wastewater, often termed back-produced fracturing or fracking water (FW), is pumped into holding ponds. One of the biggest challenges with produced water management is controlling microbial activity that could reduce the pond water's reusable layer and pose a significant environmental hazard. This study focuses on the characterization of back-produced water that has been hydraulically fractured using chemical and biological analysis and the development of a high-throughput screening method to evaluate and predict the antimicrobial effect of four naturally and commercially available acidic inhibitors (edetic acid, boric acid, tannic acid, and lactic acid) on the growth of the FW microbiome. Liquid cultures and biofilms of two laboratory model strains, the vegetative Escherichia coli MG1655, and the spore-forming Bacillus atrophaeus (also known as Bacillus globigii, BG) bacteria, were used as reference microorganisms. Planktonic bacteria in FW were more sensitive to antimicrobials than sessile bacteria in biofilms. Spore-forming BG bacteria exhibited more sensitivity to acidic inhibitors than the vegetative E. coli cells. Organic acids were the most effective bacterial growth inhibitors in liquid culture and biofilm.
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Affiliation(s)
| | | | - Maria D. King
- Biological and Agricultural Engineering, Texas A&M University, College Station, TX 77843, USA; (J.D.C.); (Y.Z.S.)
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6
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Wu J, Huang M, Liu H, Wu Y, Hu X, Wang J, Wang X. Engineering Escherichia coli to Efficiently Produce Colanic Acid with Low Molecular Mass and Viscosity. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:15811-15822. [PMID: 38975865 DOI: 10.1021/acs.jafc.4c03187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/09/2024]
Abstract
Colanic acid (CA) is exopolysaccharide that presents growing potential in the food and healthcare industry as a versatile polymer. Previously, we have constructed the Escherichia coli strain WWM16 which can efficiently produce CA. In this study, WWM16 has been further engineered to produce a higher yield of CA with low molecular mass and viscosity. The gene mcbR encoding a transcriptional factor, and the genes opgD, opgG, and opgH related to the biosynthesis of osmoregulated periplasmic glucans were deleted in E. coli WWM16, and the resulting strain WWM166 produced 18.1 g/L CA. The expression level of wcaD encoding the polymerase in WWM166 was downregulated using CRISPRi. As a result, the strain WWM166/pWpD1 could produce 49.9 g/L CA with lower molecular mass. CA products were purified from both WWM166 and WWM166/pWpD1, and their molecular mass, viscosity, fluidity, hygroscopicity, and antioxidant activity were determined and compared. These findings demonstrate the potential application of CA with different molecular masses to prolong life and protect skin in the food and cosmetic industries.
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Affiliation(s)
- Jiaxin Wu
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Ming Huang
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - He Liu
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Yuanming Wu
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xiaoqing Hu
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Jianli Wang
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xiaoyuan Wang
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
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7
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Richter A, Blei F, Hu G, Schwitalla JW, Lozano-Andrade CN, Xie J, Jarmusch SA, Wibowo M, Kjeldgaard B, Surabhi S, Xu X, Jautzus T, Phippen CBW, Tyc O, Arentshorst M, Wang Y, Garbeva P, Larsen TO, Ram AFJ, van den Hondel CAM, Maróti G, Kovács ÁT. Enhanced surface colonisation and competition during bacterial adaptation to a fungus. Nat Commun 2024; 15:4486. [PMID: 38802389 PMCID: PMC11130161 DOI: 10.1038/s41467-024-48812-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 05/13/2024] [Indexed: 05/29/2024] Open
Abstract
Bacterial-fungal interactions influence microbial community performance of most ecosystems and elicit specific microbial behaviours, including stimulating specialised metabolite production. Here, we use a co-culture experimental evolution approach to investigate bacterial adaptation to the presence of a fungus, using a simple model of bacterial-fungal interactions encompassing the bacterium Bacillus subtilis and the fungus Aspergillus niger. We find in one evolving population that B. subtilis was selected for enhanced production of the lipopeptide surfactin and accelerated surface spreading ability, leading to inhibition of fungal expansion and acidification of the environment. These phenotypes were explained by specific mutations in the DegS-DegU two-component system. In the presence of surfactin, fungal hyphae exhibited bulging cells with delocalised secretory vesicles possibly provoking an RlmA-dependent cell wall stress. Thus, our results indicate that the presence of the fungus selects for increased surfactin production, which inhibits fungal growth and facilitates the competitive success of the bacterium.
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Affiliation(s)
- Anne Richter
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Kgs Lyngby, Denmark
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Felix Blei
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
- Department Pharmaceutical Microbiology, Hans-Knöll-Institute, Friedrich-Schiller-Universität, Jena, Germany
| | - Guohai Hu
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Kgs Lyngby, Denmark
- China National GeneBank, BGI-Shenzhen, Shenzhen, China
- BGI-Shenzhen, Shenzhen, China
- Shenzhen Key Laboratory of Environmental Microbial Genomics and Application, BGI-Shenzhen, Shenzhen, China
| | - Jan W Schwitalla
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Carlos N Lozano-Andrade
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Kgs Lyngby, Denmark
| | - Jiyu Xie
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Scott A Jarmusch
- Natural Product Discovery Group, DTU Bioengineering, Technical University of Denmark, Kgs Lyngby, Denmark
| | - Mario Wibowo
- Natural Product Discovery Group, DTU Bioengineering, Technical University of Denmark, Kgs Lyngby, Denmark
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research, Singapore, Republic of Singapore
| | - Bodil Kjeldgaard
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Kgs Lyngby, Denmark
| | - Surabhi Surabhi
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Xinming Xu
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Theresa Jautzus
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Christopher B W Phippen
- Natural Product Discovery Group, DTU Bioengineering, Technical University of Denmark, Kgs Lyngby, Denmark
| | - Olaf Tyc
- Netherlands Institute of Ecology, Wageningen, The Netherlands
- Department of Internal Medicine I, Goethe University Hospital, Frankfurt, Germany
| | - Mark Arentshorst
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Yue Wang
- China National GeneBank, BGI-Shenzhen, Shenzhen, China
- BGI-Shenzhen, Shenzhen, China
| | - Paolina Garbeva
- Netherlands Institute of Ecology, Wageningen, The Netherlands
| | - Thomas Ostenfeld Larsen
- Natural Product Discovery Group, DTU Bioengineering, Technical University of Denmark, Kgs Lyngby, Denmark
| | - Arthur F J Ram
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | | | - Gergely Maróti
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
| | - Ákos T Kovács
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Kgs Lyngby, Denmark.
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany.
- Institute of Biology, Leiden University, Leiden, The Netherlands.
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8
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Xue Y, Yu C, Ouyang H, Huang J, Kang X. Uncovering the Molecular Composition and Architecture of the Bacillus subtilis Biofilm via Solid-State NMR Spectroscopy. J Am Chem Soc 2024; 146:11906-11923. [PMID: 38629727 DOI: 10.1021/jacs.4c00889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
The complex and dynamic compositions of biofilms, along with their sophisticated structural assembly mechanisms, endow them with exceptional capabilities to thrive in diverse conditions that are typically unfavorable for individual cells. Characterizing biofilms in their native state is significantly challenging due to their intrinsic complexities and the limited availability of noninvasive techniques. Here, we utilized solid-state nuclear magnetic resonance (NMR) spectroscopy to analyze Bacillus subtilis biofilms in-depth. Our data uncover a dynamically distinct organization within the biofilm: a dominant, hydrophilic, and mobile framework interspersed with minor, rigid cores of limited water accessibility. In these heterogeneous rigid cores, the major components are largely self-assembled. TasA fibers, the most robust elements, further provide a degree of mechanical support for the cell aggregates and some lipid vesicles. Notably, rigid cell aggregates can persist even without the major extracellular polymeric substance (EPS) polymers, although this leads to slight variations in their rigidity and water accessibility. Exopolysaccharides are exclusively present in the mobile domain, playing a pivotal role in its water retention property. Specifically, all water molecules are tightly bound within the biofilm matrix. These findings reveal a dual-layered defensive strategy within the biofilm: a diffusion barrier through limited water mobility in the mobile phase and a physical barrier posed by limited water accessibility in the rigid phase. Complementing these discoveries, our comprehensive, in situ compositional analysis is not only essential for delineating the sophisticated biofilm architecture but also reveals the presence of alternative genetic mechanisms for synthesizing exopolysaccharides beyond the known pathway.
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Affiliation(s)
- Yi Xue
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Chenjie Yu
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Han Ouyang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Jiaofang Huang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xue Kang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
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9
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La Corte SG, Stevens CA, Cárcamo-Oyarce G, Ribbeck K, Wingreen NS, Datta SS. Morphogenesis of bacterial colonies in polymeric environments. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.18.590088. [PMID: 38712130 PMCID: PMC11071276 DOI: 10.1101/2024.04.18.590088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Many bacteria live in polymeric fluids, such as mucus, environmental polysaccharides, and extracellular polymers in biofilms. However, lab studies typically focus on cells in polymer-free fluids. Here, we show that interactions with polymers shape a fundamental feature of bacterial life-how they proliferate in space in multicellular colonies. Using experiments, we find that when polymer is sufficiently concentrated, cells generically and reversibly form large serpentine "cables" as they proliferate. By combining experiments with biophysical theory and simulations, we demonstrate that this distinctive form of colony morphogenesis arises from an interplay between polymer-induced entropic attraction between neighboring cells and their hindered ability to diffusely separate from each other in a viscous polymer solution. Our work thus reveals a pivotal role of polymers in sculpting proliferating bacterial colonies, with implications for how they interact with hosts and with the natural environment, and uncovers quantitative principles governing colony morphogenesis in such complex environments.
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Ye Y, Ghrayeb M, Miercke S, Arif S, Müller S, Mascher T, Chai L, Zaburdaev V. Residual cells and nutrient availability guide wound healing in bacterial biofilms. SOFT MATTER 2024; 20:1047-1060. [PMID: 38205608 DOI: 10.1039/d3sm01032e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Biofilms are multicellular heterogeneous bacterial communities characterized by social-like division of labor, and remarkable robustness with respect to external stresses. Increasingly often an analogy between biofilms and arguably more complex eukaryotic tissues is being drawn. One illustrative example of where this analogy can be practically useful is the process of wound healing. While it has been extensively studied in eukaryotic tissues, the mechanism of wound healing in biofilms is virtually unexplored. Combining experiments in Bacillus subtilis bacteria, a model organism for biofilm formation, and a lattice-based theoretical model of biofilm growth, we studied how biofilms recover after macroscopic damage. We suggest that nutrient gradients and the abundance of proliferating cells are key factors augmenting wound closure. Accordingly, in the model, cell quiescence, nutrient fluxes, and biomass represented by cells and self-secreted extracellular matrix are necessary to qualitatively recapitulate the experimental results for damage repair. One of the surprising experimental findings is that residual cells, persisting in a damaged area after removal of a part of the biofilm, prominently affect the healing process. Taken together, our results outline the important roles of nutrient gradients and residual cells on biomass regrowth on macroscopic scales of the whole biofilm. The proposed combined experiment-simulation framework opens the way to further investigate the possible relation between wound healing, cell signaling and cell phenotype alternation in the local microenvironment of the wound.
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Affiliation(s)
- Yusong Ye
- Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
- Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
| | - Mnar Ghrayeb
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel.
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, Israel
| | | | - Sania Arif
- Department of Environmental Microbiology, Helmholtz-Centre for Environmental Research, Leipzig, Germany
| | - Susann Müller
- Department of Environmental Microbiology, Helmholtz-Centre for Environmental Research, Leipzig, Germany
| | | | - Liraz Chai
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel.
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Vasily Zaburdaev
- Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
- Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
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11
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Kochanowski JA, Carroll B, Asp ME, Kaputa EC, Patteson AE. Bacteria Colonies Modify Their Shear and Compressive Mechanical Properties in Response to Different Growth Substrates. ACS APPLIED BIO MATERIALS 2024. [PMID: 38193703 DOI: 10.1021/acsabm.3c00907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
Bacteria build multicellular communities termed biofilms, which are often encased in a self-secreted extracellular matrix that gives the community mechanical strength and protection against harsh chemicals. How bacteria assemble distinct multicellular structures in response to different environmental conditions remains incompletely understood. Here, we investigated the connection between bacteria colony mechanics and the colony growth substrate by measuring the oscillatory shear and compressive rheology of bacteria colonies grown on agar substrates. We found that bacteria colonies modify their own mechanical properties in response to shear and uniaxial compression in a manner that depends on the concentration of agar in their growth substrate. These findings highlight that mechanical interactions between bacteria and their microenvironments are an important element in bacteria colony development, which can aid in developing strategies to disrupt or reduce biofilm growth.
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Affiliation(s)
- Jakub A Kochanowski
- Physics Department and BioInspired Institute, Syracuse University, Syracuse, New York 13210, United States
| | - Bobby Carroll
- Physics Department and BioInspired Institute, Syracuse University, Syracuse, New York 13210, United States
| | - Merrill E Asp
- Physics Department and BioInspired Institute, Syracuse University, Syracuse, New York 13210, United States
| | - Emma C Kaputa
- Physics Department and BioInspired Institute, Syracuse University, Syracuse, New York 13210, United States
| | - Alison E Patteson
- Physics Department and BioInspired Institute, Syracuse University, Syracuse, New York 13210, United States
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12
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Tichy J, Waldherr M, Ortbauer M, Graf A, Sipek B, Jembrih-Simbuerger D, Sterflinger K, Piñar G. Pretty in pink? Complementary strategies for analysing pink biofilms on historical buildings. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166737. [PMID: 37659529 DOI: 10.1016/j.scitotenv.2023.166737] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 08/21/2023] [Accepted: 08/30/2023] [Indexed: 09/04/2023]
Abstract
Salt-weathering is a deterioration mechanism affecting building materials that results from repetitive cycles of salt crystallisation-dissolution in the porous mineral network under changing environmental conditions, causing damage to surfaces. However, an additional biodeterioration phenomenon frequently associated with salt efflorescence is the appearance of coloured biofilms, comprising halotolerant/halophilic microorganisms, containing carotenoid pigments that cause pinkish patinas. In this work, two Austrian historical salt-weathered buildings showing pink biofilms, the St. Virgil's Chapel and the Charterhouse Mauerbach, were investigated. Substrate chemistry (salt concentration/composition) was analysed by ion chromatography and X-ray diffraction to correlate these parameters with the associated microorganisms. Microbiomes were analysed by sequencing full-length 16S rRNA amplicons using Nanopore technology. Data demonstrates that microbiomes are not only influenced by salt concentration, but also by its chemical composition. The chapel showed a high overall halite (NaCl) concentration, but the factor influencing the microbiome was the presence/absence of K+. The K+ areas showed a dominance of Aliifodinibius and Salinisphaera species, capable of tolerating high salt concentrations through the "salt-in" strategy by transporting K+ into cells. Conversely, areas without K+ showed a community shift towards Halomonas species, which favour the synthesis of compatible solutes for salt tolerance. In the charterhouse, the main salts were sulphates. In areas with low concentrations, Rubrobacter species dominated, while in areas with high concentrations, Haloechinothrix species did. Among archaea, Haloccoccus species were dominant in all samples, except at high sulphate concentrations, where Halalkalicoccus prevailed. Finally, the biological pigments visible in both buildings were analysed by Raman spectroscopy, showing the same spectra in all areas investigated, regardless of the building and the microbiomes, demonstrating the presence of carotenoids in the pink biofilms. Comprehensive information on the factors affecting the microbiome associated with salt-weathered buildings should provide the basis for selecting the most appropriate desalination treatment to remove both salt efflorescence and associated biofilms.
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Affiliation(s)
- Johannes Tichy
- Institute for Natural Sciences and Technology in the Art, Academy of Fine Arts Vienna, Schillerplatz 3, A-1010 Vienna, Austria.
| | - Monika Waldherr
- Department of Applied Life Sciences/Bioengineering/Bioinformatics, FH Campus Wien, Favoritenstrasse 226, A-1100 Vienna, Austria
| | - Martin Ortbauer
- Institute for Conservation - Restoration, Academy of Fine Arts Vienna, Schillerplatz 3, A-1010 Vienna, Austria
| | - Alexandra Graf
- Department of Applied Life Sciences/Bioengineering/Bioinformatics, FH Campus Wien, Favoritenstrasse 226, A-1100 Vienna, Austria
| | - Beate Sipek
- Institute for Conservation - Restoration, Academy of Fine Arts Vienna, Schillerplatz 3, A-1010 Vienna, Austria
| | - Dubravka Jembrih-Simbuerger
- Institute for Natural Sciences and Technology in the Art, Academy of Fine Arts Vienna, Schillerplatz 3, A-1010 Vienna, Austria
| | - Katja Sterflinger
- Institute for Natural Sciences and Technology in the Art, Academy of Fine Arts Vienna, Schillerplatz 3, A-1010 Vienna, Austria
| | - Guadalupe Piñar
- Institute for Natural Sciences and Technology in the Art, Academy of Fine Arts Vienna, Schillerplatz 3, A-1010 Vienna, Austria
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13
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Wu J, Li X, Kong R, Wang J, Wang X. Analysis of biofilm expansion rate of Bacillus subtilis (MTC871) on agar substrates with different stiffness. Can J Microbiol 2023; 69:479-487. [PMID: 37379574 DOI: 10.1139/cjm-2022-0259] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2023]
Abstract
The surface morphology of mature biofilms is heterogeneous and can be divided into concentric rings wrinkles (I), labyrinthine networks wrinkles (II), radial ridges wrinkles (III), and branches wrinkles (IV), according to surface wrinkle structure and distribution characteristics. Due to the wrinkle structures, channels are formed between the biofilm and substrate and transport nutrients, water, metabolic products, etc. We find that expansion rate variations of biofilms growing on substrates with high and low agar concentrations (1.5, 2.0, 2.5 wt.%) are not in the same phase. In the first 3 days' growth, the interaction stress between biofilm and each agar substrate increases, which makes the biofilm expansion rate decreases before wrinkle pattern IV (branches) comes up. After 3 days, in the later growth stage after wrinkle pattern IV appears, the biofilm has larger expansion rate growing on 2.0 wt.% agar concentration, which has the larger wrinkle distance in wrinkle pattern IV reducing energy consumption. Our study shows that the stiff substrate does not always inhibit the biofilm expansion, although it does in the earlier stage; after that, mature biofilms acquire larger expansion rate by adjusting the growth mode through the wrinkle evolution even in nutrient extremely depletion.
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Affiliation(s)
- Jin Wu
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xianyong Li
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Rui Kong
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jiankun Wang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xiaoling Wang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
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14
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Marra D, Karapantsios T, Caserta S, Secchi E, Holynska M, Labarthe S, Polizzi B, Ortega S, Kostoglou M, Lasseur C, Karapanagiotis I, Lecuyer S, Bridier A, Noirot-Gros MF, Briandet R. Migration of surface-associated microbial communities in spaceflight habitats. Biofilm 2023; 5:100109. [PMID: 36909662 PMCID: PMC9999172 DOI: 10.1016/j.bioflm.2023.100109] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 02/05/2023] [Accepted: 02/17/2023] [Indexed: 02/26/2023] Open
Abstract
Astronauts are spending longer periods locked up in ships or stations for scientific and exploration spatial missions. The International Space Station (ISS) has been inhabited continuously for more than 20 years and the duration of space stays by crews could lengthen with the objectives of human presence on the moon and Mars. If the environment of these space habitats is designed for the comfort of astronauts, it is also conducive to other forms of life such as embarked microorganisms. The latter, most often associated with surfaces in the form of biofilm, have been implicated in significant degradation of the functionality of pieces of equipment in space habitats. The most recent research suggests that microgravity could increase the persistence, resistance and virulence of pathogenic microorganisms detected in these communities, endangering the health of astronauts and potentially jeopardizing long-duration manned missions. In this review, we describe the mechanisms and dynamics of installation and propagation of these microbial communities associated with surfaces (spatial migration), as well as long-term processes of adaptation and evolution in these extreme environments (phenotypic and genetic migration), with special reference to human health. We also discuss the means of control envisaged to allow a lasting cohabitation between these vibrant microscopic passengers and the astronauts.
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Affiliation(s)
- Daniele Marra
- Department of Chemical, Materials and Industrial Production Engineering (DICMaPi), University of Naples, Federico II, Piazzale Tecchio 80, 80125, Naples, Italy
- CEINGE, Advanced Biotechnologies, Via Gaetano Salvatore, 486, 80145, Naples, Italy
| | - Thodoris Karapantsios
- Division of Chemical Technology, School of Chemistry, Aristotle University of Thessaloniki, University Box 116, 541 24, Thessaloniki, Greece
| | - Sergio Caserta
- Department of Chemical, Materials and Industrial Production Engineering (DICMaPi), University of Naples, Federico II, Piazzale Tecchio 80, 80125, Naples, Italy
- CEINGE, Advanced Biotechnologies, Via Gaetano Salvatore, 486, 80145, Naples, Italy
| | - Eleonora Secchi
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, 8093, Zurich, Switzerland
| | | | - Simon Labarthe
- University of Bordeaux, IMB, UMR 5251, CNRS, IMB, Memphis Team, INRIA, Talence, France
| | - Bastien Polizzi
- Laboratoire de Mathématiques de Besançon, Université Bourgogne Franche-Comté, CNRS UMR-6623, Besançon, France
| | | | - Margaritis Kostoglou
- Division of Chemical Technology, School of Chemistry, Aristotle University of Thessaloniki, University Box 116, 541 24, Thessaloniki, Greece
| | | | - Ioannis Karapanagiotis
- Division of Chemical Technology, School of Chemistry, Aristotle University of Thessaloniki, University Box 116, 541 24, Thessaloniki, Greece
| | | | - Arnaud Bridier
- Fougères Laboratory, Antibiotics, Biocides, Residues and Resistance Unit, ANSES, Fougères, France
| | | | - Romain Briandet
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
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15
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Kim J, de Lorenzo V, Goñi‐Moreno Á. Pressure-dependent growth controls 3D architecture of Pseudomonas putida microcolonies. ENVIRONMENTAL MICROBIOLOGY REPORTS 2023; 15:708-715. [PMID: 37231623 PMCID: PMC10667634 DOI: 10.1111/1758-2229.13182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/12/2023] [Indexed: 05/27/2023]
Abstract
Colony formation is key to many ecological and biotechnological processes. In its early stages, colony formation involves the concourse of a number of physical and biological parameters for generation of a distinct 3D structure-the specific influence of which remains unclear. We focused on a thus far neglected aspect of the process, specifically the consequences of the differential pressure experienced by cells in the middle of a colony versus that endured by bacteria located in the growing periphery. This feature was characterized experimentally in the soil bacterium Pseudomonas putida. Using an agent-based model we recreated the growth of microcolonies in a scenario in which pressure was the only parameter affecting proliferation of cells. Simulations exposed that, due to constant collisions with other growing bacteria, cells have virtually no free space to move sideways, thereby delaying growth and boosting chances of overlapping on top of each other. This scenario was tested experimentally on agar surfaces. Comparison between experiments and simulations suggested that the inside/outside differential pressure determines growth, both timewise and in terms of spatial directions, eventually moulding colony shape. We thus argue that-at least in the case studied-mere physical pressure of growing cells suffices to explain key dynamics of colony formation.
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Affiliation(s)
- Juhyun Kim
- School of Life ScienceBK21 FOUR KNU Creative BioResearch Group Kyungpook National UniversityDaeguRepublic of Korea
| | - Víctor de Lorenzo
- Systems Biology DepartmentCentro Nacional de Biotecnología (CNB‐CSIC)Cantoblanco‐MadridSpain
| | - Ángel Goñi‐Moreno
- Centro de Biotecnología y Genómica de PlantasUniversidad Politécnica de Madrid (UPM)‐Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC)MadridSpain
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16
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Bera P, Wasim A, Ghosh P. Interplay of cell motility and self-secreted extracellular polymeric substance induced depletion effects on spatial patterning in a growing microbial colony. SOFT MATTER 2023; 19:8136-8149. [PMID: 37847026 DOI: 10.1039/d3sm01144e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
Reproducing bacteria self-organize to develop patterned biofilms in various conditions. Various factors contribute to the shaping of a multicellular bacterial organization. Here we investigate how motility force and self-secreted extracellular polymeric substances (EPS) influence bacterial cell aggregation, leading to phase-separated colonies using a particle-based/individual-based model. Our findings highlight the critical role of the interplay between motility force and depletion effects in regulating phase separation within a growing colony under far-from-equilibrium conditions. We observe that increased motility force hinders depletion-induced cell aggregation and phase segregation, necessitating a higher depletion effect for highly motile bacteria to undergo phase separation within a growing biofilm. We present a phase diagram illustrating the systematic variation of motility force and repulsive mechanical force, shedding light on the combined contributions of these two factors: self-propulsive motion and aggregation due to the depletion effect, resulting in the presence of small to large bacterial aggregates. Furthermore, our study reveals the dynamic nature of clustering, marked by changes in cluster size over time. Additionally, our findings suggest that differential dispersion among the components can lead to the localization of EPS at the periphery of a growing colony. Our study enhances the understanding of the collective dynamics of motile bacterial cells within a growing colony, particularly in the presence of a self-secreted polymer-driven depletion effect.
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Affiliation(s)
- Palash Bera
- Tata Institute of Fundamental Research Hyderabad, Telangana 500046, India
| | - Abdul Wasim
- Tata Institute of Fundamental Research Hyderabad, Telangana 500046, India
| | - Pushpita Ghosh
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Kerala, 695551, India.
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17
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Martínez-Calvo A, Trenado-Yuste C, Lee H, Gore J, Wingreen NS, Datta SS. Interfacial morphodynamics of proliferating microbial communities. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.23.563665. [PMID: 37961366 PMCID: PMC10634769 DOI: 10.1101/2023.10.23.563665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
In microbial communities, various cell types often coexist by occupying distinct spatial domains. What determines the shape of the interface between such domains-which in turn influences the interactions between cells and overall community function? Here, we address this question by developing a continuum model of a 2D spatially-structured microbial community with two distinct cell types. We find that, depending on the balance of the different cell proliferation rates and substrate friction coefficients, the interface between domains is either stable and smooth, or unstable and develops finger-like protrusions. We establish quantitative principles describing when these different interfacial behaviors arise, and find good agreement both with the results of previous experimental reports as well as new experiments performed here. Our work thus helps to provide a biophysical basis for understanding the interfacial morphodynamics of proliferating microbial communities, as well as a broader range of proliferating active systems.
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18
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Cordisco E, Zanor MI, Moreno DM, Serra DO. Selective inhibition of the amyloid matrix of Escherichia coli biofilms by a bifunctional microbial metabolite. NPJ Biofilms Microbiomes 2023; 9:81. [PMID: 37857690 PMCID: PMC10587114 DOI: 10.1038/s41522-023-00449-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Accepted: 10/12/2023] [Indexed: 10/21/2023] Open
Abstract
The propensity of bacteria to grow collectively in communities known as biofilms and their ability to overcome clinical treatments in this condition has become a major medical problem, emphasizing the need for anti-biofilm strategies. Antagonistic microbial interactions have extensively served as searching platforms for antibiotics, but their potential as sources for anti-biofilm compounds has barely been exploited. By screening for microorganisms that in agar-set pairwise interactions could antagonize Escherichia coli's ability to form macrocolony biofilms, we found that the soil bacterium Bacillus subtilis strongly inhibits the synthesis of amyloid fibers -known as curli-, which are the primary extracellular matrix (ECM) components of E. coli biofilms. We identified bacillaene, a B. subtilis hybrid non-ribosomal peptide/polyketide metabolite, previously described as a bacteriostatic antibiotic, as the effector molecule. We found that bacillaene combines both antibiotic and anti-curli functions in a concentration-dependent order that potentiates the ecological competitiveness of B. subtilis, highlighting bacillaene as a metabolite naturally optimized for microbial inhibition. Our studies revealed that bacillaene inhibits curli by directly impeding the assembly of the CsgB and CsgA curli subunits into amyloid fibers. Moreover, we found that curli inhibition occurs despite E. coli attempts to reinforce its protective ECM by inducing curli genes via a RpoS-mediated competition sensing response trigged by the threatening presence of B. subtilis. Overall, our findings illustrate the relevance of exploring microbial interactions not only for finding compounds with unknown and unique activities, but for uncovering additional functions of compounds previously categorized as antibiotics.
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Affiliation(s)
- Estefanía Cordisco
- Laboratorio de Estructura y Fisiología de Biofilms Microbianos, Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Predio CONICET Rosario, Ocampo y Esmeralda, (2000), Rosario, Argentina
| | - María Inés Zanor
- Laboratorio de Metabolismo y Señalización en Plantas, Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Predio CONICET Rosario, Ocampo y Esmeralda, (2000), Rosario, Argentina
| | - Diego Martín Moreno
- Instituto de Química Rosario (IQUIR, CONICET-UNR), Predio CONICET Rosario, Ocampo y Esmeralda, (2000) Rosario, Argentina. Facultad de Ciencias Bioquímicas y Farmacéuticas, Suipacha 531, (2000), Rosario, Argentina
| | - Diego Omar Serra
- Laboratorio de Estructura y Fisiología de Biofilms Microbianos, Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Predio CONICET Rosario, Ocampo y Esmeralda, (2000), Rosario, Argentina.
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19
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Charlton SG, Bible AN, Secchi E, Morrell‐Falvey JL, Retterer ST, Curtis TP, Chen J, Jana S. Microstructural and Rheological Transitions in Bacterial Biofilms. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2207373. [PMID: 37522628 PMCID: PMC10520682 DOI: 10.1002/advs.202207373] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 06/20/2023] [Indexed: 08/01/2023]
Abstract
Biofilms are aggregated bacterial communities structured within an extracellular matrix (ECM). ECM controls biofilm architecture and confers mechanical resistance against shear forces. From a physical perspective, biofilms can be described as colloidal gels, where bacterial cells are analogous to colloidal particles distributed in the polymeric ECM. However, the influence of the ECM in altering the cellular packing fraction (ϕ) and the resulting viscoelastic behavior of biofilm remains unexplored. Using biofilms of Pantoea sp. (WT) and its mutant (ΔUDP), the correlation between biofilm structure and its viscoelastic response is investigated. Experiments show that the reduction of exopolysaccharide production in ΔUDP biofilms corresponds with a seven-fold increase in ϕ, resulting in a colloidal glass-like structure. Consequently, the rheological signatures become altered, with the WT behaving like a weak gel, whilst the ΔUDP displayed a glass-like rheological signature. By co-culturing the two strains, biofilm ϕ is modulated which allows us to explore the structural changes and capture a change in viscoelastic response from a weak to a strong gel, and to a colloidal glass-like state. The results reveal the role of exopolysaccharide in mediating a structural transition in biofilms and demonstrate a correlation between biofilm structure and viscoelastic response.
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Affiliation(s)
- Samuel G.V. Charlton
- Department of Civil, Environmental and Geomatic EngineeringInstitute of Environmental EngineeringETH ZurichZurich8049Switzerland
- School of EngineeringNewcastle UniversityNewcastle Upon TyneNE1 7RUUK
| | - Amber N. Bible
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37830USA
| | - Eleonora Secchi
- Department of Civil, Environmental and Geomatic EngineeringInstitute of Environmental EngineeringETH ZurichZurich8049Switzerland
| | | | - Scott T. Retterer
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37830USA
- Center for Nanophase Material SciencesOak Ridge National LaboratoryOak RidgeTN37830USA
| | - Thomas P. Curtis
- School of EngineeringNewcastle UniversityNewcastle Upon TyneNE1 7RUUK
| | - Jinju Chen
- School of EngineeringNewcastle UniversityNewcastle Upon TyneNE1 7RUUK
| | - Saikat Jana
- School of EngineeringNewcastle UniversityNewcastle Upon TyneNE1 7RUUK
- School of EngineeringUlster UniversityBelfastBT15 1APUK
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20
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Winkle JJ, Saha S, Essman J, Bennett MR, Ott W, Josić K, Mugler A. Signaling in microbial communities with open boundaries. Biophys J 2023; 122:2808-2817. [PMID: 37300250 PMCID: PMC10397789 DOI: 10.1016/j.bpj.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 05/11/2023] [Accepted: 06/05/2023] [Indexed: 06/12/2023] Open
Abstract
Microbial communities such as swarms or biofilms often form at the interfaces of solid substrates and open fluid flows. At the same time, in laboratory environments these communities are commonly studied using microfluidic devices with media flows and open boundaries. Extracellular signaling within these communities is therefore subject to different constraints than signaling within classic, closed-boundary systems such as developing embryos or tissues, yet is understudied by comparison. Here, we use mathematical modeling to show how advective-diffusive boundary flows and population geometry impact cell-cell signaling in monolayer microbial communities. We reveal conditions where the intercellular signaling lengthscale depends solely on the population geometry and not on diffusion or degradation, as commonly expected. We further demonstrate that diffusive coupling with the boundary flow can produce signal gradients within an isogenic population, even when there is no flow within the population. We use our theory to provide new insights into the signaling mechanisms of published experimental results, and we make several experimentally verifiable predictions. Our research highlights the importance of carefully evaluating boundary dynamics and environmental geometry when modeling microbial cell-cell signaling and informs the study of cell behaviors in both natural and synthetic systems.
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Affiliation(s)
- James J Winkle
- Department of Mathematics, University of Houston, Houston, Texas
| | - Soutick Saha
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana
| | - Joseph Essman
- Department of BioSciences, Rice University, Houston, Texas
| | | | - William Ott
- Department of Mathematics, University of Houston, Houston, Texas.
| | - Krešimir Josić
- Department of Mathematics, University of Houston, Houston, Texas; Department of BioSciences, Rice University, Houston, Texas; Department of Biology and Biochemistry, University of Houston, Houston, Texas.
| | - Andrew Mugler
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana; Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania.
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21
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Villa F, Ludwig N, Mazzini S, Scaglioni L, Fuchs AL, Tripet B, Copié V, Stewart PS, Cappitelli F. A desiccated dual-species subaerial biofilm reprograms its metabolism and affects water dynamics in limestone. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 868:161666. [PMID: 36669662 DOI: 10.1016/j.scitotenv.2023.161666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 01/10/2023] [Accepted: 01/13/2023] [Indexed: 06/17/2023]
Abstract
Understanding the impact of sessile communities on underlying materials is of paramount importance in stone conservation. Up until now, the critical role of subaerial biofilms (SABs) whether they are protective or deteriorative remains unclear, especially under desiccation. The interest in desiccated SABs is raised by the prediction of an increase in drought events in the next decades that will affect the Mediterranean regions' rich stone heritage as never before. Thus, the main goal of this research is to study the effects of desiccation on both the biofilms' eco-physiology and its impacts on the lithic substrate. To this end, we used a dual-species model system composed of a phototroph and a chemotroph to simulate biofilm behavior on stone heritage. We found that drought altered the phototroph-chemotroph balance and enriched the biofilm matrix with proteins and DNA. Desiccated SABs underwent a shift in metabolism to fermentation and a decrease in oxidative stress. Additionally, desiccated SABs changed the water-related dynamics (adsorption, evaporation, and wetting properties) in limestone. Water absorption experiments showed that desiccated SABs protected the stone from rapid water uptake, while a thermographic survey indicated a delay in water evaporation. Spilling-drop tests revealed a change in the wettability of the stone-SAB interface, which affected the water transport properties of the stone. Finally, desiccated SABs reduced stone swelling in the presence of water vapor. The biodeteriorative and bioprotective implications of desiccated SABs on the stone were ultimately assessed.
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Affiliation(s)
- F Villa
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l'Ambiente, Università degli Studi di Milano, 20133 Milan, Italy.
| | - N Ludwig
- Dipartimento di Fisica Aldo Pontremoli, Università degli Studi di Milano, 20133 Milan, Italy.
| | - S Mazzini
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l'Ambiente, Università degli Studi di Milano, 20133 Milan, Italy.
| | - L Scaglioni
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l'Ambiente, Università degli Studi di Milano, 20133 Milan, Italy.
| | - A L Fuchs
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, USA
| | - B Tripet
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, USA.
| | - V Copié
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, USA.
| | - P S Stewart
- Center for Biofilm Engineering, Montana State University, Bozeman 59717, USA.
| | - F Cappitelli
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l'Ambiente, Università degli Studi di Milano, 20133 Milan, Italy.
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22
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Deforet M. Long-range alteration of the physical environment mediates cooperation between Pseudomonas aeruginosa swarming colonies. Environ Microbiol 2023. [PMID: 36964975 DOI: 10.1111/1462-2920.16373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 03/15/2023] [Indexed: 03/27/2023]
Abstract
Pseudomonas aeruginosa makes and secretes massive amounts of rhamnolipid surfactants that enable swarming motility over biogel surfaces. But how these rhamnolipids interact with biogels to assist swarming remains unclear. Here, I use a combination of optical techniques across scales and genetically engineered strains to demonstrate that rhamnolipids can induce agar gel swelling over distances >10,000× the body size of an individual cell. The swelling front is on the micrometric scale and is easily visible using shadowgraphy. Rhamnolipid transport is not restricted to the surface of the gel but occurs through the whole thickness of the plate and, consequently, the spreading dynamics depend on the local thickness. Surprisingly, rhamnolipids can cross the whole gel and induce swelling on the opposite side of a two-face Petri dish. The swelling front delimits an area where the mechanical properties of the surface properties are modified: water wets the surface more easily, which increases the motility of individual bacteria and enables collective motility. A genetically engineered mutant unable to secrete rhamnolipids (ΔrhlA), and therefore unable to swarm, is rescued from afar with rhamnolipids produced by a remote colony. These results exemplify the remarkable capacity of bacteria to change the physical environment around them and its ecological consequences.
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Affiliation(s)
- Maxime Deforet
- Sorbonne Université, Centre National de la Recherche Scientifique, Laboratoire Jean Perrin, LJP, Paris, 75005, France
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23
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Luo S, Liu Y, Luo H, Jing G. Glycerol Droplet Spreading on Growing Bacillus Subtilis Biofilms. MICROMACHINES 2023; 14:599. [PMID: 36985005 PMCID: PMC10055872 DOI: 10.3390/mi14030599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/24/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
Bacterial biofilm is a three-dimensional matrix composed of a large number of living bacterial individuals. The strong bio-interaction between the bacteria and its self-secreted matrix environment strengthens the mechanical integrity of the biofilm and the sustainable resistance of bacteria to antibiotics. As a soft surface, the biofilm is expected to present different dynamical wetting behavior in response to shear stress, which is, however, less known. Here, the spreading of liquid droplet on Bacillus subtilis biofilm at its different growing phases was experimentally investigated. Due to the viscoelastic response of the biofilm to fast spreading of the droplet, three stages were identified as inertial, viscous stages, and a longer transition in between. The physical heterogeneity of growing biofilm correlates with the spreading scaling within the inertial stage, followed by the possible chemical variation after a critical growing time. By using the duration of inertial spreading, the characteristic time scale was successfully linked to the shear modulus of the elastic dissipation of the biofilm. This measurement suggests a facile, non-destructive and in vivo method to understand the mechanical instability of this living matter.
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Affiliation(s)
| | | | - Hao Luo
- Correspondence: (Y.L.); (H.L.)
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24
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Brence J, Džeroski S, Todorovski L. Dimensionally-consistent equation discovery through probabilistic attribute grammars. Inf Sci (N Y) 2023. [DOI: 10.1016/j.ins.2023.03.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
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25
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Bera P, Wasim A, Ghosh P. A mechanistic understanding of microcolony morphogenesis: coexistence of mobile and sessile aggregates. SOFT MATTER 2023; 19:1034-1045. [PMID: 36648295 DOI: 10.1039/d2sm01365g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Most bacteria in the natural environment self-organize into collective phases such as cell clusters, swarms, patterned colonies, or biofilms. Several intrinsic and extrinsic factors, such as growth, motion, and physicochemical interactions, govern the occurrence of different phases and their coexistence. Hence, predicting the conditions under which a collective phase emerges due to individual-level interactions is crucial. Here we develop a particle-based biophysical model of bacterial cells and self-secreted extracellular polymeric substances (EPS) to decipher the interplay of growth, motility-mediated dispersal, and mechanical interactions during microcolony morphogenesis. We show that the microcolony dynamics and architecture significantly vary depending upon the heterogeneous EPS production. In particular, microcolony shows the coexistence of both motile and sessile aggregates rendering a transition towards biofilm formation. We identified that the interplay of differential dispersion and the mechanical interactions among the components of the colony determines the fate of the colony morphology. Our results provide a significant understanding of the mechano-self-regulation during biofilm morphogenesis and open up possibilities of designing experiments to test the predictions.
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Affiliation(s)
- Palash Bera
- Tata Institute of Fundamental Research Hyderabad, Telangana, 500046, India
| | - Abdul Wasim
- Tata Institute of Fundamental Research Hyderabad, Telangana, 500046, India
| | - Pushpita Ghosh
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Kerala, 695551, India.
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Zhang W, Bertinetti L, Yavuzsoy EC, Gao C, Schneck E, Fratzl P. Submicron-Sized In Situ Osmotic Pressure Sensors for In Vitro Applications in Biology. Adv Healthc Mater 2022; 12:e2202373. [PMID: 36541931 DOI: 10.1002/adhm.202202373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/06/2022] [Indexed: 12/24/2022]
Abstract
Physical forces are important cues in determining the development and the normal function of biological tissues. While forces generated by molecular motors have been widely studied, forces resulting from osmotic gradients have been less considered in this context. A possible reason is the lack of direct in situ measurement methods that can be applied to cell and organ culture systems. Herein, novel kinds of resonance energy transfer (FRET)-based liposomal sensors are developed, so that their sensing range and sensitivity can be adjusted to satisfy physiological osmotic conditions. Several types of sensors are prepared, either based on polyethylene glycol- (PEG)ylated liposomes with steric stabilization and stealth property or on crosslinked liposomes capable of enduring relatively harsh environments for liposomes (e.g., in the presence of biosurfactants). The sensors are demonstrated to be effective in the measurement of osmotic pressures in pre-osteoblastic in vitro cell culture systems by means of FRET microscopy. This development paves the way toward the in situ sensing of osmotic pressures in biological culture systems.
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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.,B CUBE Center for Molecular Bioengineering, Technische Universität Dresden, 01307, Dresden, Germany
| | - Efe Cuma Yavuzsoy
- Department of Biomaterials, 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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Morris RJ, Stevenson D, Sukhodub T, Stanley-Wall NR, MacPhee CE. Density and temperature controlled fluid extraction in a bacterial biofilm is determined by poly-γ-glutamic acid production. NPJ Biofilms Microbiomes 2022; 8:98. [PMID: 36528619 PMCID: PMC9759580 DOI: 10.1038/s41522-022-00361-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
A hallmark of microbial biofilms is the self-production of an extracellular molecular matrix that encases the resident cells. The matrix provides protection from the environment, while spatial heterogeneity of gene expression influences the structural morphology and colony spreading dynamics. Bacillus subtilis is a model bacterial system used to uncover the regulatory pathways and key building blocks required for biofilm growth and development. In this work, we report on the emergence of a highly active population of bacteria during the early stages of biofilm formation, facilitated by the extraction of fluid from the underlying agar substrate. We trace the origin of this fluid extraction to the production of poly-γ-glutamic acid (PGA). The flagella-dependent activity develops behind a moving front of fluid that propagates from the boundary of the biofilm towards the interior. The extent of fluid proliferation is controlled by the presence of extracellular polysaccharides (EPS). We also find that PGA production is positively correlated with higher temperatures, resulting in high-temperature mature biofilm morphologies that are distinct from the rugose colony biofilm architecture typically associated with B. subtilis. Although previous reports have suggested that PGA production does not play a major role in biofilm morphology in the undomesticated isolate NCIB 3610, our results suggest that this strain produces distinct biofilm matrices in response to environmental conditions.
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Affiliation(s)
- Ryan J. Morris
- grid.4305.20000 0004 1936 7988National Biofilms Innovation Centre, School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD UK
| | - David Stevenson
- grid.8241.f0000 0004 0397 2876Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH UK
| | - Tetyana Sukhodub
- grid.8241.f0000 0004 0397 2876Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH UK
| | - Nicola R. Stanley-Wall
- grid.8241.f0000 0004 0397 2876Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH UK
| | - Cait E. MacPhee
- grid.4305.20000 0004 1936 7988National Biofilms Innovation Centre, School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD UK
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Wu M, Zhang Z, Zhang X, Dong L, Liu C, Chen Y. Propionibacterium freudenreichii-Assisted Approach Reduces N 2O Emission and Improves Denitrification via Promoting Substrate Uptake and Metabolism. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:16895-16906. [PMID: 36366772 DOI: 10.1021/acs.est.2c05674] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
N2O emission is often encountered during biodenitrification. In this paper, a new approach of using microorganisms to promote substrate uptake and metabolism to reduce denitrification intermediate accumulation was reported. With the introduction of Propionibacterium freudenreichii to a biodenitrification system, N2O and nitrite accumulation was, respectively, decreased by 74 and 60% and the denitrification efficiency was increased by 150% at the time of 24 h with P. freudenreichii/groundwater denitrifier of 1/5 (OD600). Propionate, produced by P. freudenreichii, only accelerated nitrate removal and was not the main reason for the decreased intermediate accumulation. The proteomic and enzyme analyses revealed that P. freudenreichii stimulated biofilm formation by upregulating proteins involved in porin forming, putrescine biosynthesis, spermidine/putrescine transport, and quorum sensing and upregulated transport proteins, which facilitated the uptake of the carbon source, nitrate, and Fe and Mo (the required catalytic sites of denitrification enzymes). Further investigation revealed that P. freudenreichii activated the methylmalonyl-CoA pathway in the denitrifier and promoted it to synthesize heme/heme d1, the groups of denitrification enzymes and electron transfer proteins, which upregulated the expression of denitrifying enzyme proteins and enhanced the ratio of NosZ to NorB, resulting in the increase of generation, transfer, and consumption of electrons in biodenitrification. Therefore, a significant reduction in the denitrification intermediate accumulation and an improvement in the denitrification efficiency were observed.
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Affiliation(s)
- Meirou Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Zhiqi Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Xin Zhang
- Shanghai Municipal Engineering Design Institute (Group) Co. LTD, 901 Zhongshan North Second Road, Shanghai 200092, China
| | - Lei Dong
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
- Shanghai Municipal Engineering Design Institute (Group) Co. LTD, 901 Zhongshan North Second Road, Shanghai 200092, China
| | - Chao Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
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Charlton SGV, Kurz DL, Geisel S, Jimenez-Martinez J, Secchi E. The role of biofilm matrix composition in controlling colony expansion and morphology. Interface Focus 2022; 12:20220035. [PMID: 36330326 PMCID: PMC9560791 DOI: 10.1098/rsfs.2022.0035] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 09/09/2022] [Indexed: 08/01/2023] Open
Abstract
Biofilms are biological viscoelastic gels composed of bacterial cells embedded in a self-secreted polymeric extracellular matrix (ECM). In environmental settings, such as in the rhizosphere and phyllosphere, biofilm colonization occurs at the solid-air interface. The biofilms' ability to colonize and expand over these surfaces depends on the formation of osmotic gradients and ECM viscoelastic properties. In this work, we study the influence of biofilm ECM components on its viscoelasticity and expansion, using the model organism Bacillus subtilis and deletion mutants of its three major ECM components, TasA, EPS and BslA. Using a multi-scale approach, we quantified macro-scale viscoelasticity and expansion dynamics. Furthermore, we used a microsphere assay to visualize the micro-scale expansion patterns. We find that the viscoelastic phase angle Φ is likely the best viscoelastic parameter correlating to biofilm expansion dynamics. Moreover, we quantify the sensitivity of the biofilm to changes in substrate water potential as a function of ECM composition. Finally, we find that the deletion of ECM components significantly increases the coherence of micro-scale colony expansion patterns. These results demonstrate the influence of ECM viscoelasticity and substrate water potential on the expansion of biofilm colonies on wet surfaces at the air-solid interface, commonly found in natural environments.
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Affiliation(s)
- Samuel G. V. Charlton
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zürich, Zürich, Switzerland
| | - Dorothee L. Kurz
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zürich, Zürich, Switzerland
- Department Water Resources and Drinking Water, Swiss Federal Institute of Aquatic Science and Technology, Eawag, Dübendorf, Switzerland
| | - Steffen Geisel
- Department of Materials, Soft Materials, ETH Zürich, Zürich, Switzerland
| | - Joaquin Jimenez-Martinez
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zürich, Zürich, Switzerland
- Department Water Resources and Drinking Water, Swiss Federal Institute of Aquatic Science and Technology, Eawag, Dübendorf, Switzerland
| | - Eleonora Secchi
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zürich, Zürich, Switzerland
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Wang X, Blumenfeld R, Feng XQ, Weitz DA. 'Phase transitions' in bacteria - From structural transitions in free living bacteria to phenotypic transitions in bacteria within biofilms. Phys Life Rev 2022; 43:98-138. [PMID: 36252408 DOI: 10.1016/j.plrev.2022.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 09/30/2022] [Indexed: 12/05/2022]
Abstract
Phase transitions are common in inanimate systems and have been studied extensively in natural sciences. Less explored are the rich transitions that take place at the micro- and nano-scales in biological systems. In conventional phase transitions, large-scale properties of the media change discontinuously in response to continuous changes in external conditions. Such changes play a significant role in the dynamic behaviours of organisms. In this review, we focus on some transitions in both free-living and biofilms of bacteria. Particular attention is paid to the transitions in the flagellar motors and filaments of free-living bacteria, in cellular gene expression during the biofilm growth, in the biofilm morphology transitions during biofilm expansion, and in the cell motion pattern transitions during the biofilm formation. We analyse the dynamic characteristics and biophysical mechanisms of these phase transition phenomena and point out the parallels between these transitions and conventional phase transitions. We also discuss the applications of some theoretical and numerical methods, established for conventional phase transitions in inanimate systems, in bacterial biofilms.
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Affiliation(s)
- Xiaoling Wang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China; John A. Paulson School of Engineering and Applied Sciences, Harvard University, 9 Oxford St, Cambridge, MA, 02138, USA.
| | - Raphael Blumenfeld
- Gonville & Caius College, University of Cambridge, Trinity St., Cambridge CB2 1TA, UK
| | - Xi-Qiao Feng
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - David A Weitz
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, 9 Oxford St, Cambridge, MA, 02138, USA; Department of Physics, Harvard University, 9 Oxford St, Cambridge, MA, 02138, USA
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31
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Eigentler L, Davidson FA, Stanley-Wall NR. Mechanisms driving spatial distribution of residents in colony biofilms: an interdisciplinary perspective. Open Biol 2022; 12:220194. [PMID: 36514980 PMCID: PMC9748781 DOI: 10.1098/rsob.220194] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Biofilms are consortia of microorganisms that form collectives through the excretion of extracellular matrix compounds. The importance of biofilms in biological, industrial and medical settings has long been recognized due to their emergent properties and impact on surrounding environments. In laboratory situations, one commonly used approach to study biofilm formation mechanisms is the colony biofilm assay, in which cell communities grow on solid-gas interfaces on agar plates after the deposition of a population of founder cells. The residents of a colony biofilm can self-organize to form intricate spatial distributions. The assay is ideally suited to coupling with mathematical modelling due to the ability to extract a wide range of metrics. In this review, we highlight how interdisciplinary approaches have provided deep insights into mechanisms causing the emergence of these spatial distributions from well-mixed inocula.
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Affiliation(s)
- Lukas Eigentler
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK,Mathematics, School of Science and Engineering, University of Dundee, Dundee DD1 4HN, UK
| | - Fordyce A. Davidson
- Mathematics, School of Science and Engineering, University of Dundee, Dundee DD1 4HN, UK
| | - Nicola R. Stanley-Wall
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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32
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Bakarji J, Callaham J, Brunton SL, Kutz JN. Dimensionally consistent learning with Buckingham Pi. NATURE COMPUTATIONAL SCIENCE 2022; 2:834-844. [PMID: 38177386 DOI: 10.1038/s43588-022-00355-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 10/12/2022] [Indexed: 01/06/2024]
Abstract
In the absence of governing equations, dimensional analysis is a robust technique for extracting insights and finding symmetries in physical systems. Given measurement variables and parameters, the Buckingham Pi theorem provides a procedure for finding a set of dimensionless groups that spans the solution space, although this set is not unique. We propose an automated approach using the symmetric and self-similar structure of available measurement data to discover the dimensionless groups that best collapse these data to a lower dimensional space according to an optimal fit. We develop three data-driven techniques that use the Buckingham Pi theorem as a constraint: (1) a constrained optimization problem with a non-parametric input-output fitting function, (2) a deep learning algorithm (BuckiNet) that projects the input parameter space to a lower dimension in the first layer and (3) a technique based on sparse identification of nonlinear dynamics to discover dimensionless equations whose coefficients parameterize the dynamics. We explore the accuracy, robustness and computational complexity of these methods and show that they successfully identify dimensionless groups in three example problems: a bead on a rotating hoop, a laminar boundary layer and Rayleigh-Bénard convection.
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Affiliation(s)
- Joseph Bakarji
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA.
| | - Jared Callaham
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA.
| | - Steven L Brunton
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA.
| | - J Nathan Kutz
- Department of Applied Mathematics, University of Washington, Seattle, WA, USA.
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Addo KA, Li L, Li H, Yu Y, Xiao X. Osmotic stress relief antibiotic tolerance of 1,8-cineole in biofilm persister cells of Escherichia coli O157:H7 and expression of toxin-antitoxin system genes. Microb Pathog 2022; 173:105883. [DOI: 10.1016/j.micpath.2022.105883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/10/2022] [Accepted: 11/11/2022] [Indexed: 11/17/2022]
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Abstract
The morphogenesis of two-dimensional bacterial colonies has been well studied. However, little is known about the colony morphologies of bacteria growing in three dimensions, despite the prevalence of three-dimensional environments (e.g., soil, inside hosts) as natural bacterial habitats. Using experiments on bacteria in granular hydrogel matrices, we find that dense multicellular colonies growing in three dimensions undergo a common morphological instability and roughen, adopting a characteristic broccoli-like morphology when they exceed a critical size. Analysis of a continuum “active fluid” model of the expanding colony reveals that this behavior originates from an interplay of competition for nutrients with growth-driven colony expansion, both of which vary spatially. These results shed light on the fundamental biophysical principles underlying growth in three dimensions. How do growing bacterial colonies get their shapes? While colony morphogenesis is well studied in two dimensions, many bacteria grow as large colonies in three-dimensional (3D) environments, such as gels and tissues in the body or subsurface soils and sediments. Here, we describe the morphodynamics of large colonies of bacteria growing in three dimensions. Using experiments in transparent 3D granular hydrogel matrices, we show that dense colonies of four different species of bacteria generically become morphologically unstable and roughen as they consume nutrients and grow beyond a critical size—eventually adopting a characteristic branched, broccoli-like morphology independent of variations in the cell type and environmental conditions. This behavior reflects a key difference between two-dimensional (2D) and 3D colonies; while a 2D colony may access the nutrients needed for growth from the third dimension, a 3D colony inevitably becomes nutrient limited in its interior, driving a transition to unstable growth at its surface. We elucidate the onset of the instability using linear stability analysis and numerical simulations of a continuum model that treats the colony as an “active fluid” whose dynamics are driven by nutrient-dependent cellular growth. We find that when all dimensions of the colony substantially exceed the nutrient penetration length, nutrient-limited growth drives a 3D morphological instability that recapitulates essential features of the experimental observations. Our work thus provides a framework to predict and control the organization of growing colonies—as well as other forms of growing active matter, such as tumors and engineered living materials—in 3D environments.
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Henzel T, Nijjer J, Chockalingam S, Wahdat H, Crosby AJ, Yan J, Cohen T. Interfacial cavitation. PNAS NEXUS 2022; 1:pgac217. [PMID: 36714841 PMCID: PMC9802248 DOI: 10.1093/pnasnexus/pgac217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/28/2022] [Indexed: 11/18/2022]
Abstract
Cavitation has long been recognized as a crucial predictor, or precursor, to the ultimate failure of various materials, ranging from ductile metals to soft and biological materials. Traditionally, cavitation in solids is defined as an unstable expansion of a void or a defect within a material. The critical applied load needed to trigger this instability -- the critical pressure -- is a lengthscale independent material property and has been predicted by numerous theoretical studies for a breadth of constitutive models. While these studies usually assume that cavitation initiates from defects in the bulk of an otherwise homogeneous medium, an alternative and potentially more ubiquitous scenario can occur if the defects are found at interfaces between two distinct media within the body. Such interfaces are becoming increasingly common in modern materials with the use of multimaterial composites and layer-by-layer additive manufacturing methods. However, a criterion to determine the threshold for interfacial failure, in analogy to the bulk cavitation limit, has yet to be reported. In this work, we fill this gap. Our theoretical model captures a lengthscale independent limit for interfacial cavitation, and is shown to agree with our observations at two distinct lengthscales, via two different experimental systems. To further understand the competition between the two cavitation modes (bulk versus interface), we expand our investigation beyond the elastic response to understand the ensuing unstable propagation of delamination at the interface. A phase diagram summarizes these results, showing regimes in which interfacial failure becomes the dominant mechanism.
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Affiliation(s)
| | | | | | - Hares Wahdat
- Polymer Science and Engineering Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Alfred J Crosby
- Polymer Science and Engineering Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Jing Yan
- To whom correspondence should be addressed:
| | - Tal Cohen
- To whom correspondence should be addressed:
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36
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Dong F, Liu S, Zhang D, Zhang J, Wang X. Matrix-producing cells formed 'Van Gogh bundles' facilitate Bacillus subtilis biofilm self-healing. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:822-827. [PMID: 35676766 DOI: 10.1111/1758-2229.13099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/12/2022] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
Biofilms grow and expand through cell differentiation into various phenotypes, which have different functions and cooperate with each other. In our experiments, we find that biofilms can heal after damaged, and we also find there is a special structure near the cut, which is called the 'Van Gogh bundles' by Jordi et al. because of its resemblance to Van Gogh's famous painting 'The Starry Night'. Here, we study the 'Van Gogh bundles' structure evolution near the cut area, and how 'Van Gogh bundles' structure facilitates the cut healing by observing microscopic images of bacterial colonies growing from wild-type and mutant strains. We find that the amount of matrix-producing cells contributes to the 'Van Gogh bundles' structure, such as curvature. Through the comparison of curvatures of 'Van Gogh bundles' and the rate of the cut healing, we find that the smaller the curvature, the faster healing rate. To better explain the above experiment observations, we establish an individual-based model and simulate the formation and growth of 'Van Gogh bundles' along the cut by giving rules for an individual cell like cell growth, division and turning rules, and also 'Van Gogh bundles' fold division rule.
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Affiliation(s)
- Fulin Dong
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, China
| | - Song Liu
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, China
| | - Duohuai Zhang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, China
| | - Jinchang Zhang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, China
| | - Xiaoling Wang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, China
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
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37
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Yuan X, Eldred LI, Sundin GW. Exopolysaccharides amylovoran and levan contribute to sliding motility in the fire blight pathogen Erwinia amylovora. Environ Microbiol 2022; 24:4738-4754. [PMID: 36054324 PMCID: PMC9826367 DOI: 10.1111/1462-2920.16193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 08/31/2022] [Indexed: 01/11/2023]
Abstract
Erwinia amylovora, the causative agent of fire blight, uses flagella-based motilities to translocate to host plant natural openings; however, little is known about how this bacterium migrates systemically in the apoplast. Here, we reveal a novel surface motility mechanism, defined as sliding, in E. amylovora. Deletion of flagella assembly genes did not affect this movement, whereas deletion of biosynthesis genes for the exopolysaccharides (EPSs) amylovoran and levan resulted in non-sliding phenotypes. Since EPS production generates osmotic pressure that potentially powers sliding, we validated this mechanism by demonstrating that water potential positively contributes to sliding. In addition, no sliding was observed when the water potential of the surface was lower than -0.5 MPa. Sliding is a passive motility mechanism. We further show that the force of gravity plays a critical role in directing E. amylovora sliding on unconfined surfaces but has a negligible effect when cells are sliding in confined microcapillaries, in which EPS-dependent osmotic pressure acts as the main force. Although amylovoran and levan are both required for sliding, we demonstrate that they exhibit different roles in bacterial communities. In summary, our study provides fundamental knowledge for a better understanding of mechanisms that drive bacterial sliding motility.
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Affiliation(s)
- Xiaochen Yuan
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
| | - Lauren I. Eldred
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
| | - George W. Sundin
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
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38
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Jautzus T, van Gestel J, Kovács ÁT. Complex extracellular biology drives surface competition during colony expansion in Bacillus subtilis. THE ISME JOURNAL 2022; 16:2320-2328. [PMID: 35790818 PMCID: PMC9477810 DOI: 10.1038/s41396-022-01279-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/13/2022] [Accepted: 06/20/2022] [Indexed: 04/29/2023]
Abstract
Many bacteria grow on surfaces in nature, where they form cell collectives that compete for space. Within these collectives, cells often secrete molecules that benefit surface spreading by, for example, reducing surface tension or promoting filamentous growth. Although we have a detailed understanding of how these molecules are produced, much remains unknown about their role in surface competition. Here we examine sliding motility in Bacillus subtilis and compare how secreted molecules, essential for sliding, affect intraspecific cooperation and competition on a surface. We specifically examine (i) the lipopeptide surfactin, (ii) the hydrophobin protein BslA, and (iii) exopolysaccharides (EPS). We find that these molecules have a distinct effect on surface competition. Whereas surfactin acts like a common good, which is costly to produce and benefits cells throughout the surface, BslA and EPS are cost-free and act locally. Accordingly, surfactin deficient mutants can exploit the wild-type strain in competition for space, while BslA and EPS mutants cannot. Supported by a mathematical model, we show that three factors are important in predicting the outcome of surface competition: the costs of molecule synthesis, the private benefits of molecule production, and the diffusion rate. Our results underscore the intricate extracellular biology that can drive bacterial surface competition.
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Affiliation(s)
- Theresa Jautzus
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Jordi van Gestel
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Ákos T Kovács
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, 07743, Jena, Germany.
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark.
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39
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Palmer JD, Foster KR. The evolution of spectrum in antibiotics and bacteriocins. Proc Natl Acad Sci U S A 2022; 119:e2205407119. [PMID: 36099299 PMCID: PMC9499554 DOI: 10.1073/pnas.2205407119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 08/05/2022] [Indexed: 12/02/2022] Open
Abstract
A key property of many antibiotics is that they will kill or inhibit a diverse range of microbial species. This broad-spectrum of activity has its evolutionary roots in ecological competition, whereby bacteria and other microbes use antibiotics to suppress other strains and species. However, many bacteria also use narrow-spectrum toxins, such as bacteriocins, that principally target conspecifics. Why has such a diversity in spectrum evolved? Here, we develop an evolutionary model to understand antimicrobial spectrum. Our first model recapitulates the intuition that broad-spectrum is best, because it enables a microbe to kill a wider diversity of competitors. However, this model neglects an important property of antimicrobials: They are commonly bound, sequestered, or degraded by the cells they target. Incorporating this toxin loss reveals a major advantage to narrow-spectrum toxins: They target the strongest ecological competitor and avoid being used up on less important species. Why then would broad-spectrum toxins ever evolve? Our model predicts that broad-spectrum toxins will be favored by natural selection if a strain is highly abundant and can overpower both its key competitor and other species. We test this prediction by compiling and analyzing a database of the regulation and spectrum of toxins used in inter-bacterial competition. This analysis reveals a strong association between broad-spectrum toxins and density-dependent regulation, indicating that they are indeed used when strains are abundant. Our work provides a rationale for why bacteria commonly evolve narrow-spectrum toxins such as bacteriocins and suggests that the evolution of antibiotics proper is a signature of ecological dominance.
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Affiliation(s)
- Jacob D. Palmer
- Department of Biology, University of Oxford, Oxford, OX1 3RB, United Kingdom
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
| | - Kevin R. Foster
- Department of Biology, University of Oxford, Oxford, OX1 3RB, United Kingdom
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
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40
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Porter M, Davidson FA, MacPhee CE, Stanley-Wall NR. Systematic microscopical analysis reveals obligate synergy between extracellular matrix components during Bacillus subtilis colony biofilm development. Biofilm 2022; 4:100082. [PMID: 36148433 PMCID: PMC9486643 DOI: 10.1016/j.bioflm.2022.100082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 08/11/2022] [Accepted: 08/11/2022] [Indexed: 12/03/2022] Open
Abstract
Single-species bacterial colony biofilms often present recurring morphologies that are thought to be of benefit to the population of cells within and are known to be dependent on the self-produced extracellular matrix. However, much remains unknown in terms of the developmental process at the single cell level. Here, we design and implement systematic time-lapse imaging and quantitative analyses of the growth of Bacillus subtilis colony biofilms. We follow the development from the initial deposition of founding cells through to the formation of large-scale complex structures. Using the model biofilm strain NCIB 3610, we examine the movement dynamics of the growing biomass and compare them with those displayed by a suite of otherwise isogenic matrix-mutant strains. Correspondingly, we assess the impact of an incomplete matrix on biofilm morphologies and sessile growth rate. Our results indicate that radial expansion of colony biofilms results from the division of bacteria at the biofilm periphery rather than being driven by swelling due to fluid intake. Moreover, we show that lack of exopolysaccharide production has a negative impact on cell division rate, and the extracellular matrix components act synergistically to give the biomass the structural strength to produce aerial protrusions and agar substrate-deforming ability.
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41
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Competition between growth and shear stress drives intermittency in preferential flow paths in porous medium biofilms. Proc Natl Acad Sci U S A 2022; 119:e2122202119. [PMID: 35858419 PMCID: PMC9335220 DOI: 10.1073/pnas.2122202119] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Bacteria in porous media, such as soils, aquifers, and filters, often form surface-attached communities known as biofilms. Biofilms are affected by fluid flow through the porous medium, for example, for nutrient supply, and they, in turn, affect the flow. A striking example of this interplay is the strong intermittency in flow that can occur when biofilms nearly clog the porous medium. Intermittency manifests itself as the rapid opening and slow closing of individual preferential flow paths (PFPs) through the biofilm-porous medium structure, leading to continual spatiotemporal rearrangement. The drastic changes to the flow and mass transport induced by intermittency can affect the functioning and efficiency of natural and industrial systems. Yet, the mechanistic origin of intermittency remains unexplained. Here, we show that the mechanism driving PFP intermittency is the competition between microbial growth and shear stress. We combined microfluidic experiments quantifying Bacillus subtilis biofilm formation and behavior in synthetic porous media for different pore sizes and flow rates with a mathematical model accounting for flow through the biofilm and biofilm poroelasticity to reveal the underlying mechanisms. We show that the closing of PFPs is driven by microbial growth, controlled by nutrient mass flow. Opposing this, we find that the opening of PFPs is driven by flow-induced shear stress, which increases as a PFP becomes narrower due to microbial growth, causing biofilm compression and rupture. Our results demonstrate that microbial growth and its competition with shear stresses can lead to strong temporal variability in flow and transport conditions in bioclogged porous media.
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42
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Geisel S, Secchi E, Vermant J. The role of surface adhesion on the macroscopic wrinkling of biofilms. eLife 2022; 11:e76027. [PMID: 35723588 PMCID: PMC9208754 DOI: 10.7554/elife.76027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 06/01/2022] [Indexed: 12/14/2022] Open
Abstract
Biofilms, bacterial communities of cells encased by a self-produced matrix, exhibit a variety of three-dimensional structures. Specifically, channel networks formed within the bulk of the biofilm have been identified to play an important role in the colonies' viability by promoting the transport of nutrients and chemicals. Here, we study channel formation and focus on the role of the adhesion of the biofilm matrix to the substrate in Pseudomonas aeruginosa biofilms grown under constant flow in microfluidic channels. We perform phase contrast and confocal laser scanning microscopy to examine the development of the biofilm structure as a function of the substrates' surface energy. The formation of the wrinkles and folds is triggered by a mechanical buckling instability, controlled by biofilm growth rate and the film's adhesion to the substrate. The three-dimensional folding gives rise to hollow channels that rapidly increase the effective volume occupied by the biofilm and facilitate bacterial movement inside them. The experiments and analysis on mechanical instabilities for the relevant case of a bacterial biofilm grown during flow enable us to predict and control the biofilm morphology.
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Affiliation(s)
- Steffen Geisel
- Laboratory for Soft Materials, Department of Materials, ETH ZurichZurichSwitzerland
| | - Eleonora Secchi
- Department of Civil, Environmental and Geomatic Engineering, ETH ZurichZurichSwitzerland
| | - Jan Vermant
- Laboratory for Soft Materials, Department of Materials, ETH ZurichZurichSwitzerland
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43
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Fortune GT, Oliveira NM, Goldstein RE. Biofilm Growth under Elastic Confinement. PHYSICAL REVIEW LETTERS 2022; 128:178102. [PMID: 35570462 DOI: 10.1103/physrevlett.128.178102] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
Bacteria often form surface-bound communities, embedded in a self-produced extracellular matrix, called biofilms. Quantitative studies of bioflim growth have typically focused on unconfined expansion above solid or semisolid surfaces, leading to exponential radial growth. This geometry does not accurately reflect the natural or biomedical contexts in which biofilms grow in confined spaces. Here, we consider one of the simplest confined geometries: a biofilm growing laterally in the space between a solid surface and an overlying elastic sheet. A poroelastic framework is utilized to derive the radial growth rate of the biofilm; it reveals an additional self-similar expansion regime, governed by the Poisson's ratio of the matrix, leading to a finite maximum radius, consistent with our experimental observations of growing Bacillus subtilis biofilms confined by polydimethylsiloxane.
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Affiliation(s)
- George T Fortune
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom
| | - Nuno M Oliveira
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom
| | - Raymond E Goldstein
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom
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44
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Asp ME, Ho Thanh MT, Germann DA, Carroll RJ, Franceski A, Welch RD, Gopinath A, Patteson AE. Spreading rates of bacterial colonies depend on substrate stiffness and permeability. PNAS NEXUS 2022; 1:pgac025. [PMID: 36712798 PMCID: PMC9802340 DOI: 10.1093/pnasnexus/pgac025] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/25/2022] [Accepted: 03/09/2022] [Indexed: 02/01/2023]
Abstract
The ability of bacteria to colonize and grow on different surfaces is an essential process for biofilm development. Here, we report the use of synthetic hydrogels with tunable stiffness and porosity to assess physical effects of the substrate on biofilm development. Using time-lapse microscopy to track the growth of expanding Serratia marcescens colonies, we find that biofilm colony growth can increase with increasing substrate stiffness, unlike what is found on traditional agar substrates. Using traction force microscopy-based techniques, we find that biofilms exert transient stresses correlated over length scales much larger than a single bacterium, and that the magnitude of these forces also increases with increasing substrate stiffness. Our results are consistent with a model of biofilm development in which the interplay between osmotic pressure arising from the biofilm and the poroelastic response of the underlying substrate controls biofilm growth and morphology.
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Affiliation(s)
- Merrill E Asp
- Physics Department, Syracuse University, Syracuse, NY 13244, USA,BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Minh-Tri Ho Thanh
- Physics Department, Syracuse University, Syracuse, NY 13244, USA,BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Danielle A Germann
- Physics Department, Syracuse University, Syracuse, NY 13244, USA,BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Robert J Carroll
- Physics Department, Syracuse University, Syracuse, NY 13244, USA,BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Alana Franceski
- BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA,Biology Department, Syracuse University, Syracuse, NY 13244, USA
| | - Roy D Welch
- BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA,Biology Department, Syracuse University, Syracuse, NY 13244, USA
| | - Arvind Gopinath
- Department of Bioengineering, University of California, Merced, Merced, CA 95343, USA,Health Sciences Research Institute, University of California, Merced, Merced, CA 95343, USA
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45
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Bremer E, Hoffmann T, Dempwolff F, Bedrunka P, Bange G. The many faces of the unusual biofilm activator RemA. Bioessays 2022; 44:e2200009. [PMID: 35289951 DOI: 10.1002/bies.202200009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 11/08/2022]
Abstract
Biofilms can be viewed as tissue-like structures in which microorganisms are organized in a spatial and functional sophisticated manner. Biofilm formation requires the orchestration of a highly integrated network of regulatory proteins to establish cell differentiation and production of a complex extracellular matrix. Here, we discuss the role of the essential Bacillus subtilis biofilm activator RemA. Despite intense research on biofilms, RemA is a largely underappreciated regulatory protein. RemA forms donut-shaped octamers with the potential to assemble into dimeric superstructures. The presumed DNA-binding mode suggests that RemA organizes its target DNA into nucleosome-like structures, which are the basis for its role as transcriptional activator. We discuss how RemA affects gene expression in the context of biofilm formation, and its regulatory interplay with established components of the biofilm regulatory network, such as SinR, SinI, SlrR, and SlrA. We emphasize the additional role of RemA played in nitrogen metabolism and osmotic-stress adjustment.
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Affiliation(s)
- Erhard Bremer
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | - Tamara Hoffmann
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | - Felix Dempwolff
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | - Patricia Bedrunka
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | - Gert Bange
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany.,Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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46
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Patteson AE, Asp ME, Janmey PA. Materials science and mechanosensitivity of living matter. APPLIED PHYSICS REVIEWS 2022; 9:011320. [PMID: 35392267 PMCID: PMC8969880 DOI: 10.1063/5.0071648] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 02/08/2022] [Indexed: 06/14/2023]
Abstract
Living systems are composed of molecules that are synthesized by cells that use energy sources within their surroundings to create fascinating materials that have mechanical properties optimized for their biological function. Their functionality is a ubiquitous aspect of our lives. We use wood to construct furniture, bacterial colonies to modify the texture of dairy products and other foods, intestines as violin strings, bladders in bagpipes, and so on. The mechanical properties of these biological materials differ from those of other simpler synthetic elastomers, glasses, and crystals. Reproducing their mechanical properties synthetically or from first principles is still often unattainable. The challenge is that biomaterials often exist far from equilibrium, either in a kinetically arrested state or in an energy consuming active state that is not yet possible to reproduce de novo. Also, the design principles that form biological materials often result in nonlinear responses of stress to strain, or force to displacement, and theoretical models to explain these nonlinear effects are in relatively early stages of development compared to the predictive models for rubberlike elastomers or metals. In this Review, we summarize some of the most common and striking mechanical features of biological materials and make comparisons among animal, plant, fungal, and bacterial systems. We also summarize some of the mechanisms by which living systems develop forces that shape biological matter and examine newly discovered mechanisms by which cells sense and respond to the forces they generate themselves, which are resisted by their environment, or that are exerted upon them by their environment. Within this framework, we discuss examples of how physical methods are being applied to cell biology and bioengineering.
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Affiliation(s)
- Alison E. Patteson
- Physics Department and BioInspired Institute, Syracuse University, Syracuse NY, 13244, USA
| | - Merrill E. Asp
- Physics Department and BioInspired Institute, Syracuse University, Syracuse NY, 13244, USA
| | - Paul A. Janmey
- Institute for Medicine and Engineering and Departments of Physiology and Physics & Astronomy, University of Pennsylvania, Philadelphia PA, 19104, USA
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47
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Padgett-Pagliai KA, Pagliai FA, da Silva DR, Gardner CL, Lorca GL, Gonzalez CF. Osmotic stress induces long-term biofilm survival in Liberibacter crescens. BMC Microbiol 2022; 22:52. [PMID: 35148684 PMCID: PMC8832773 DOI: 10.1186/s12866-022-02453-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 01/21/2022] [Indexed: 11/24/2022] Open
Abstract
Citrus greening, also known as Huanglongbing (HLB), is a devastating citrus plant disease caused predominantly by Liberibacter asiaticus. While nearly all Liberibacter species remain uncultured, here we used the culturable L. crescens BT-1 as a model to examine physiological changes in response to the variable osmotic conditions and nutrient availability encountered within the citrus host. Similarly, physiological responses to changes in growth temperature and dimethyl sulfoxide concentrations were also examined, due to their use in many of the currently employed therapies to control the spread of HLB. Sublethal heat stress was found to induce the expression of genes related to tryptophan biosynthesis, while repressing the expression of ribosomal proteins. Osmotic stress induces expression of transcriptional regulators involved in expression of extracellular structures, while repressing the biosynthesis of fatty acids and aromatic amino acids. The effects of osmotic stress were further evaluated by quantifying biofilm formation of L. crescens in presence of increasing sucrose concentrations at different stages of biofilm formation, where sucrose-induced osmotic stress delayed initial cell attachment while enhancing long-term biofilm viability. Our findings revealed that exposure to osmotic stress is a significant contributing factor to the long term survival of L. crescens and, possibly, to the pathogenicity of other Liberibacter species.
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Affiliation(s)
- Kaylie A Padgett-Pagliai
- Department of Microbiology and Cell Science, Genetics Institute, Institute of Food and Agricultural Sciences, University of Florida, 2033 Mowry Road, PO Box 103610, Gainesville, FL, 32610-3610, USA
| | - Fernando A Pagliai
- Department of Microbiology and Cell Science, Genetics Institute, Institute of Food and Agricultural Sciences, University of Florida, 2033 Mowry Road, PO Box 103610, Gainesville, FL, 32610-3610, USA
| | - Danilo R da Silva
- Department of Microbiology and Cell Science, Genetics Institute, Institute of Food and Agricultural Sciences, University of Florida, 2033 Mowry Road, PO Box 103610, Gainesville, FL, 32610-3610, USA
| | - Christopher L Gardner
- Department of Microbiology and Cell Science, Genetics Institute, Institute of Food and Agricultural Sciences, University of Florida, 2033 Mowry Road, PO Box 103610, Gainesville, FL, 32610-3610, USA
| | - Graciela L Lorca
- Department of Microbiology and Cell Science, Genetics Institute, Institute of Food and Agricultural Sciences, University of Florida, 2033 Mowry Road, PO Box 103610, Gainesville, FL, 32610-3610, USA
| | - Claudio F Gonzalez
- Department of Microbiology and Cell Science, Genetics Institute, Institute of Food and Agricultural Sciences, University of Florida, 2033 Mowry Road, PO Box 103610, Gainesville, FL, 32610-3610, USA.
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48
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Tam AKY, Harding B, Green JEF, Balasuriya S, Binder BJ. Thin-film lubrication model for biofilm expansion under strong adhesion. Phys Rev E 2022; 105:014408. [PMID: 35193209 DOI: 10.1103/physreve.105.014408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 11/26/2021] [Indexed: 06/14/2023]
Abstract
Understanding microbial biofilm growth is important to public health because biofilms are a leading cause of persistent clinical infections. In this paper, we develop a thin-film model for microbial biofilm growth on a solid substratum to which it adheres strongly. We model biofilms as two-phase viscous fluid mixtures of living cells and extracellular fluid. The model explicitly tracks the movement, depletion, and uptake of nutrients and incorporates cell proliferation via a nutrient-dependent source term. Notably, our thin-film reduction is two dimensional and includes the vertical dependence of cell volume fraction. Numerical solutions show that this vertical dependence is weak for biologically feasible parameters, reinforcing results from previous models in which this dependence was neglected. We exploit this weak dependence by writing and solving a simplified one-dimensional model that is computationally more efficient than the full model. We use both the one- and two-dimensional models to predict how model parameters affect expansion speed and biofilm thickness. This analysis reveals that expansion speed depends on cell proliferation, nutrient availability, cell-cell adhesion on the upper surface, and slip on the biofilm-substratum interface. Our numerical solutions provide a means to qualitatively distinguish between the extensional flow and lubrication regimes, and quantitative predictions that can be tested in future experiments.
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Affiliation(s)
- Alexander K Y Tam
- School of Mathematical Sciences, Queensland University of Technology, Brisbane Queensland 4000, Australia
- School of Mathematics and Physics, The University of Queensland, St. Lucia Queensland 4072, Australia
- School of Mathematical Sciences, The University of Adelaide, Adelaide SA 5005, Australia
| | - Brendan Harding
- School of Mathematical Sciences, The University of Adelaide, Adelaide SA 5005, Australia
- School of Mathematics and Statistics, Victoria University of Wellington, Wellington 6140, New Zealand
| | - J Edward F Green
- School of Mathematical Sciences, The University of Adelaide, Adelaide SA 5005, Australia
| | - Sanjeeva Balasuriya
- School of Mathematical Sciences, The University of Adelaide, Adelaide SA 5005, Australia
| | - Benjamin J Binder
- School of Mathematical Sciences, The University of Adelaide, Adelaide SA 5005, Australia
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49
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Dong F, Liu S, Zhang D, Zhang J, Wang X, Zhao H. Osmotic Pressure Induced by Extracellular Matrix Drives Bacillus Subtilis Biofilms’ Self-healing. Comput Biol Chem 2022; 97:107632. [DOI: 10.1016/j.compbiolchem.2022.107632] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 01/08/2022] [Accepted: 01/13/2022] [Indexed: 01/01/2023]
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50
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Ziege R, Tsirigoni AM, Large B, Serra DO, Blank KG, Hengge R, Fratzl P, Bidan CM. Adaptation of Escherichia coli Biofilm Growth, Morphology, and Mechanical Properties to Substrate Water Content. ACS Biomater Sci Eng 2021; 7:5315-5325. [PMID: 34672512 PMCID: PMC8579398 DOI: 10.1021/acsbiomaterials.1c00927] [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] [Indexed: 12/03/2022]
Abstract
![]()
Biofilms are complex
living materials that form as bacteria become
embedded in a matrix of self-produced protein and polysaccharide fibers.
In addition to their traditional association with chronic infections
or clogging of pipelines, biofilms currently gain interest as a potential
source of functional material. On nutritive hydrogels, micron-sized Escherichia coli cells can build centimeter-large biofilms.
During this process, bacterial proliferation, matrix production, and
water uptake introduce mechanical stresses in the biofilm that are
released through the formation of macroscopic delaminated buckles
in the third dimension. To clarify how substrate water content could
be used to tune biofilm material properties, we quantified E. coli biofilm growth, delamination dynamics, and rigidity
as a function of water content of the nutritive substrates. Time-lapse
microscopy and computational image analysis revealed that softer substrates
with high water content promote biofilm spreading kinetics, while
stiffer substrates with low water content promote biofilm delamination.
The delaminated buckles observed on biofilm cross sections appeared
more bent on substrates with high water content, while they tended
to be more vertical on substrates with low water content. Both wet
and dry biomass, accumulated over 4 days of culture, were larger in
biofilms cultured on substrates with high water content, despite extra
porosity within the matrix layer. Finally, microindentation analysis
revealed that substrates with low water content supported the formation
of stiffer biofilms. This study shows that E. coli biofilms respond to substrate water content, which might be used
for tuning their material properties in view of further applications.
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Affiliation(s)
- Ricardo Ziege
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | | | - Bastien Large
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Diego O Serra
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany.,Institute of Molecular and Cell Biology, 2000 Rosario, Argentina
| | - Kerstin G Blank
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Regine Hengge
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Peter Fratzl
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Cécile M Bidan
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
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