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Gonyar LA, Sauder AB, Mortensen L, Willsey GG, Kendall MM. The yad and yeh fimbrial loci influence gene expression and virulence in enterohemorrhagic Escherichia coli O157:H7. mSphere 2024:e0012424. [PMID: 38904402 DOI: 10.1128/msphere.00124-24] [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: 02/15/2024] [Accepted: 05/15/2024] [Indexed: 06/22/2024] Open
Abstract
Fimbriae are essential virulence factors for many bacterial pathogens. Fimbriae are extracellular structures that attach bacteria to surfaces. Thus, fimbriae mediate a critical step required for any pathogen to establish infection by anchoring a bacterium to host tissue. The human pathogen enterohemorrhagic Escherichia coli (EHEC) O157:H7encodes 16 fimbriae that may be important for EHEC to initiate infection and allow for productive expression of virulence traits important in later stages of infection, including a type III secretion system (T3SS) and Shiga toxin; however, the roles of most EHEC fimbriae are largely uncharacterized. Here, we provide evidence that two EHEC fimbriae, Yad and Yeh, modulate expression of diverse genes including genes encoding T3SS and Shiga toxin and that these fimbriae are required for robust colonization of the gastrointestinal tract. These findings reveal a significant and previously unappreciated role for fimbriae in bacterial pathogenesis as important determinants of virulence gene expression.IMPORTANCEFimbriae are extracellular proteinaceous structures whose defining role is to anchor bacteria to surfaces. This is a fundamental step for bacterial pathogens to establish infection in a host. Here, we show that the contributions of fimbriae to pathogenesis are more complex. Specifically, we demonstrate that fimbriae influence expression of virulence traits essential for disease progression in the intestinal pathogen enterohemorrhagic Escherichia coli. Gram-positive and Gram-negative bacteria express multiple fimbriae; therefore, these findings may have broad implications for understanding how pathogens use fimbriae, beyond adhesion, to initiate infection and coordinate gene expression, which ultimately results in disease.
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Affiliation(s)
- Laura A Gonyar
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Amber B Sauder
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Lindsay Mortensen
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Graham G Willsey
- Department of Microbiology and Molecular Genetics, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
| | - Melissa M Kendall
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
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2
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Costa CM, Cardoso VF, Martins P, Correia DM, Gonçalves R, Costa P, Correia V, Ribeiro C, Fernandes MM, Martins PM, Lanceros-Méndez S. Smart and Multifunctional Materials Based on Electroactive Poly(vinylidene fluoride): Recent Advances and Opportunities in Sensors, Actuators, Energy, Environmental, and Biomedical Applications. Chem Rev 2023; 123:11392-11487. [PMID: 37729110 PMCID: PMC10571047 DOI: 10.1021/acs.chemrev.3c00196] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Indexed: 09/22/2023]
Abstract
From scientific and technological points of view, poly(vinylidene fluoride), PVDF, is one of the most exciting polymers due to its overall physicochemical characteristics. This polymer can crystalize into five crystalline phases and can be processed in the form of films, fibers, membranes, and specific microstructures, being the physical properties controllable over a wide range through appropriate chemical modifications. Moreover, PVDF-based materials are characterized by excellent chemical, mechanical, thermal, and radiation resistance, and for their outstanding electroactive properties, including high dielectric, piezoelectric, pyroelectric, and ferroelectric response, being the best among polymer systems and thus noteworthy for an increasing number of technologies. This review summarizes and critically discusses the latest advances in PVDF and its copolymers, composites, and blends, including their main characteristics and processability, together with their tailorability and implementation in areas including sensors, actuators, energy harvesting and storage devices, environmental membranes, microfluidic, tissue engineering, and antimicrobial applications. The main conclusions, challenges and future trends concerning materials and application areas are also presented.
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Affiliation(s)
- Carlos M. Costa
- Physics
Centre of Minho and Porto Universities (CF-UM-UP), University of Minho, 4710-057 Braga, Portugal
- Laboratory
of Physics for Materials and Emergent Technologies, LapMET, University of Minho, 4710-057 Braga, Portugal
- Institute
of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, 4710-057 Braga, Portugal
| | - Vanessa F. Cardoso
- CMEMS-UMinho, University of
Minho, DEI, Campus de
Azurém, 4800-058 Guimarães, Portugal
- LABBELS-Associate
Laboratory, Campus de
Gualtar, 4800-058 Braga, Guimarães, Portugal
| | - Pedro Martins
- Physics
Centre of Minho and Porto Universities (CF-UM-UP), University of Minho, 4710-057 Braga, Portugal
- Laboratory
of Physics for Materials and Emergent Technologies, LapMET, University of Minho, 4710-057 Braga, Portugal
- Institute
of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, 4710-057 Braga, Portugal
| | | | - Renato Gonçalves
- Center of
Chemistry, University of Minho, 4710-057 Braga, Portugal
| | - Pedro Costa
- Physics
Centre of Minho and Porto Universities (CF-UM-UP), University of Minho, 4710-057 Braga, Portugal
- Laboratory
of Physics for Materials and Emergent Technologies, LapMET, University of Minho, 4710-057 Braga, Portugal
- Institute
for Polymers and Composites IPC, University
of Minho, 4804-533 Guimarães, Portugal
| | - Vitor Correia
- CMEMS-UMinho, University of
Minho, DEI, Campus de
Azurém, 4800-058 Guimarães, Portugal
- LABBELS-Associate
Laboratory, Campus de
Gualtar, 4800-058 Braga, Guimarães, Portugal
| | - Clarisse Ribeiro
- Physics
Centre of Minho and Porto Universities (CF-UM-UP), University of Minho, 4710-057 Braga, Portugal
- Laboratory
of Physics for Materials and Emergent Technologies, LapMET, University of Minho, 4710-057 Braga, Portugal
| | - Margarida M. Fernandes
- CMEMS-UMinho, University of
Minho, DEI, Campus de
Azurém, 4800-058 Guimarães, Portugal
- LABBELS-Associate
Laboratory, Campus de
Gualtar, 4800-058 Braga, Guimarães, Portugal
| | - Pedro M. Martins
- Institute
of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, 4710-057 Braga, Portugal
- Centre
of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Senentxu Lanceros-Méndez
- Physics
Centre of Minho and Porto Universities (CF-UM-UP), University of Minho, 4710-057 Braga, Portugal
- Laboratory
of Physics for Materials and Emergent Technologies, LapMET, University of Minho, 4710-057 Braga, Portugal
- BCMaterials,
Basque Center for Materials, Applications
and Nanostructures, UPV/EHU
Science Park, 48940 Leioa, Spain
- Ikerbasque, Basque Foundation for Science, 48009 Bilbao, Spain
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3
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Wang L, Wong YC, Correira JM, Wancura M, Geiger CJ, Webster SS, Touhami A, Butler BJ, O'Toole GA, Langford RM, Brown KA, Dortdivanlioglu B, Webb L, Cosgriff-Hernandez E, Gordon VD. The accumulation and growth of Pseudomonas aeruginosa on surfaces is modulated by surface mechanics via cyclic-di-GMP signaling. NPJ Biofilms Microbiomes 2023; 9:78. [PMID: 37816780 PMCID: PMC10564899 DOI: 10.1038/s41522-023-00436-x] [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: 05/31/2023] [Accepted: 09/12/2023] [Indexed: 10/12/2023] Open
Abstract
Attachment of bacteria onto a surface, consequent signaling, and accumulation and growth of the surface-bound bacterial population are key initial steps in the formation of pathogenic biofilms. While recent reports have hinted that surface mechanics may affect the accumulation of bacteria on that surface, the processes that underlie bacterial perception of surface mechanics and modulation of accumulation in response to surface mechanics remain largely unknown. We use thin and thick hydrogels coated on glass to create composite materials with different mechanics (higher elasticity for thin composites; lower elasticity for thick composites) but with the same surface adhesivity and chemistry. The mechanical cue stemming from surface mechanics is elucidated using experiments with the opportunistic human pathogen Pseudomonas aeruginosa combined with finite-element modeling. Adhesion to thin composites results in greater changes in mechanical stress and strain in the bacterial envelope than does adhesion to thick composites with identical surface chemistry. Using quantitative microscopy, we find that adhesion to thin composites also results in higher cyclic-di-GMP levels, which in turn result in lower motility and less detachment, and thus greater accumulation of bacteria on the surface than does adhesion to thick composites. Mechanics-dependent c-di-GMP production is mediated by the cell-surface-exposed protein PilY1. The biofilm lag phase, which is longer for bacterial populations on thin composites than on thick composites, is also mediated by PilY1. This study shows clear evidence that bacteria actively regulate differential accumulation on surfaces of different stiffnesses via perceiving varied mechanical stress and strain upon surface engagement.
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Affiliation(s)
- Liyun Wang
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Yu-Chern Wong
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX, 78712, USA
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Joshua M Correira
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Megan Wancura
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Chris J Geiger
- Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA
| | | | - Ahmed Touhami
- Department of Physics and Astronomy University of Texas Rio Grande Valley, One West University Blvd, Brownsville, TX, 78520, USA
| | - Benjamin J Butler
- Surfaces, Microstructure and Fracture Group, Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
| | | | - Richard M Langford
- Surfaces, Microstructure and Fracture Group, Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Katherine A Brown
- Surfaces, Microstructure and Fracture Group, Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
- Oden Institute for Computational Engineering & Sciences, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Berkin Dortdivanlioglu
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Lauren Webb
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712, USA
| | | | - Vernita D Gordon
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX, 78712, USA.
- LaMontagne Center for Infectious Disease, The University of Texas at Austin, Austin, TX, 78712, USA.
- Interdisciplinary Life Sciences Graduate Program, The University of Texas at Austin, Austin, TX, 78712, USA.
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4
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Gamraoui A, Hamimed S, Landoulsi A, Chatti A. Musico-bioremediation of seafood canning wastewater by Yarrowia lipolytica. World J Microbiol Biotechnol 2023; 39:303. [PMID: 37688626 DOI: 10.1007/s11274-023-03746-6] [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: 06/11/2023] [Accepted: 08/28/2023] [Indexed: 09/11/2023]
Abstract
Due to the lack of water resources and the harmful effects of wastewater on environment and human health, treatment of wastewater becomes necessary. The present study explored the effect of musical sounds on the biological treatment of seafood canning wastewater by using Yarrowia lipolytica. Our results showed that low frequency (21 Hz to 1356 Hz) and high frequency (21 Hz to 16,214 Hz) musical sounds stimulated the growth of Y. lipolytica and increased the polluant removal efficiency. Such treatment decreased significantly the chemical oxygen demand (COD) and salinity as well as the color of this wastewater. Our study revealed that low frequency musical sounds are more effective in COD (87.5%) and salinity (44%) reduction as well as the decolorization (86.46%) of this effluent. Additionally, after 7 days of incubation significant yeast cell dry biomass (3.46 ± 0.22 g/L) and single cell proteins (46.45 ± 0.7 mg/g) were obtained under low frequency waves. Musico-bioremediation represents an innovative ecotechnological approach to wastewater treatment with low operating costs and significant environmental benefits.
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Affiliation(s)
- Afef Gamraoui
- Laboratory of Biochemistry and Molecular Biology, University of Carthage, Faculty of Sciences of Bizerte, 7021, Zarzouna, Tunisia
| | - Selma Hamimed
- Laboratory of Biochemistry and Molecular Biology, University of Carthage, Faculty of Sciences of Bizerte, 7021, Zarzouna, Tunisia
| | - Ahmed Landoulsi
- Laboratory of Biochemistry and Molecular Biology, University of Carthage, Faculty of Sciences of Bizerte, 7021, Zarzouna, Tunisia
| | - Abdelwaheb Chatti
- Laboratory of Biochemistry and Molecular Biology, University of Carthage, Faculty of Sciences of Bizerte, 7021, Zarzouna, Tunisia.
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5
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Ozu M, Galizia L, Alvear-Arias JJ, Fernández M, Caviglia A, Zimmermann R, Guastaferri F, Espinoza-Muñoz N, Sutka M, Sigaut L, Pietrasanta LI, González C, Amodeo G, Garate JA. Mechanosensitive aquaporins. Biophys Rev 2023; 15:497-513. [PMID: 37681084 PMCID: PMC10480384 DOI: 10.1007/s12551-023-01098-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/04/2023] [Indexed: 09/09/2023] Open
Abstract
Cellular systems must deal with mechanical forces to satisfy their physiological functions. In this context, proteins with mechanosensitive properties play a crucial role in sensing and responding to environmental changes. The discovery of aquaporins (AQPs) marked a significant breakthrough in the study of water transport. Their transport capacity and regulation features make them key players in cellular processes. To date, few AQPs have been reported to be mechanosensitive. Like mechanosensitive ion channels, AQPs respond to tension changes in the same range. However, unlike ion channels, the aquaporin's transport rate decreases as tension increases, and the molecular features of the mechanism are unknown. Nevertheless, some clues from mechanosensitive ion channels shed light on the AQP-membrane interaction. The GxxxG motif may play a critical role in the water permeation process associated with structural features in AQPs. Consequently, a possible gating mechanism triggered by membrane tension changes would involve a conformational change in the cytoplasmic extreme of the single file region of the water pathway, where glycine and histidine residues from loop B play a key role. In view of their transport capacity and their involvement in relevant processes related to mechanical forces, mechanosensitive AQPs are a fundamental piece of the puzzle for understanding cellular responses.
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Affiliation(s)
- Marcelo Ozu
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Luciano Galizia
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Juan José Alvear-Arias
- Interdisciplinary Center of Neurosciences of Valparaiso, University of Valparaiso, CINV, 2360102 Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Santiago, Chile
| | - Miguel Fernández
- Interdisciplinary Center of Neurosciences of Valparaiso, University of Valparaiso, CINV, 2360102 Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Santiago, Chile
| | - Agustín Caviglia
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Rosario Zimmermann
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Florencia Guastaferri
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Present Address: Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET-UNR), Rosario, Argentina
| | - Nicolás Espinoza-Muñoz
- Interdisciplinary Center of Neurosciences of Valparaiso, University of Valparaiso, CINV, 2360102 Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Santiago, Chile
| | - Moira Sutka
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Lorena Sigaut
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Física, Buenos Aires, Argentina
- Instituto de Física de Buenos Aires (IFIBA), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Lía Isabel Pietrasanta
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Física, Buenos Aires, Argentina
- Instituto de Física de Buenos Aires (IFIBA), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Carlos González
- Millennium Nucleus in NanoBioPhysics, Santiago, Chile
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL 33136 USA
- Present Address: Molecular Bioscience Department, University of Texas, Austin, TX 78712 USA
| | - Gabriela Amodeo
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - José Antonio Garate
- Interdisciplinary Center of Neurosciences of Valparaiso, University of Valparaiso, CINV, 2360102 Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Santiago, Chile
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Bellavista, Santiago, Chile
- Centro Científico y Tecnológico de Excelencia Ciencia y Vida, Universidad San Sebastián, 7750000 Santiago, Chile
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6
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Wang L, Wong YC, Correira JM, Wancura M, Geiger CJ, Webster SS, Butler BJ, O’Toole GA, Langford RM, Brown KA, Dortdivanlioglu B, Webb L, Cosgriff-Hernandez E, Gordon VD. Bacterial mechanosensing of surface stiffness promotes signaling and growth leading to biofilm formation by Pseudomonas aeruginosa. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.26.525810. [PMID: 36747833 PMCID: PMC9900894 DOI: 10.1101/2023.01.26.525810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The attachment of bacteria onto a surface, consequent signaling, and the accumulation and growth of the surface-bound bacterial population are key initial steps in the formation of pathogenic biofilms. While recent reports have hinted that the stiffness of a surface may affect the accumulation of bacteria on that surface, the processes that underlie bacterial perception of and response to surface stiffness are unknown. Furthermore, whether, and how, the surface stiffness impacts biofilm development, after initial accumulation, is not known. We use thin and thick hydrogels to create stiff and soft composite materials, respectively, with the same surface chemistry. Using quantitative microscopy, we find that the accumulation, motility, and growth of the opportunistic human pathogen Pseudomonas aeruginosa respond to surface stiffness, and that these are linked through cyclic-di-GMP signaling that depends on surface stiffness. The mechanical cue stemming from surface stiffness is elucidated using finite-element modeling combined with experiments - adhesion to stiffer surfaces results in greater changes in mechanical stress and strain in the bacterial envelope than does adhesion to softer surfaces with identical surface chemistry. The cell-surface-exposed protein PilY1 acts as a mechanosensor, that upon surface engagement, results in higher cyclic-di-GMP levels, lower motility, and greater accumulation on stiffer surfaces. PilY1 impacts the biofilm lag phase, which is extended for bacteria attaching to stiffer surfaces. This study shows clear evidence that bacteria actively respond to different stiffness of surfaces where they adhere via perceiving varied mechanical stress and strain upon surface engagement.
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Affiliation(s)
- Liyun Wang
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX 78712, USA
- Present address: Max Planck Institute for Terrestrial Microbiology, Marburg, 35043, Germany
| | - Yu-Chern Wong
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Joshua M. Correira
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712 USA
| | - Megan Wancura
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712 USA
| | - Chris J Geiger
- Geisel School of Medicine at Dartmouth, Hanover, NH 03755 USA
| | | | - Benjamin J. Butler
- Surfaces, Microstructure and Fracture Group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | | | - Richard M. Langford
- Surfaces, Microstructure and Fracture Group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Katherine A. Brown
- Surfaces, Microstructure and Fracture Group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
- Oden Institute for Computational Engineering & Sciences, The University of Texas at Austin, Austin, TX 78712
| | - Berkin Dortdivanlioglu
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, TX 78712 USA
| | - Lauren Webb
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712 USA
| | | | - Vernita D. Gordon
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX 78712, USA
- LaMontagne Center for Infectious Disease, The University of Texas at Austin, Austin, TX 78712, USA
- Interdisciplinary Life Sciences Graduate Program, The University of Texas at Austin, Austin, TX 78712, USA
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7
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Cell Envelope Stress Response in Pseudomonas aeruginosa. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:147-184. [DOI: 10.1007/978-3-031-08491-1_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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8
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Sultana A, Zare M, Luo H, Ramakrishna S. Surface Engineering Strategies to Enhance the In Situ Performance of Medical Devices Including Atomic Scale Engineering. Int J Mol Sci 2021; 22:11788. [PMID: 34769219 PMCID: PMC8583812 DOI: 10.3390/ijms222111788] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/14/2021] [Accepted: 10/26/2021] [Indexed: 12/13/2022] Open
Abstract
Decades of intense scientific research investigations clearly suggest that only a subset of a large number of metals, ceramics, polymers, composites, and nanomaterials are suitable as biomaterials for a growing number of biomedical devices and biomedical uses. However, biomaterials are prone to microbial infection due to Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Staphylococcus epidermidis (S. epidermidis), hepatitis, tuberculosis, human immunodeficiency virus (HIV), and many more. Hence, a range of surface engineering strategies are devised in order to achieve desired biocompatibility and antimicrobial performance in situ. Surface engineering strategies are a group of techniques that alter or modify the surface properties of the material in order to obtain a product with desired functionalities. There are two categories of surface engineering methods: conventional surface engineering methods (such as coating, bioactive coating, plasma spray coating, hydrothermal, lithography, shot peening, and electrophoretic deposition) and emerging surface engineering methods (laser treatment, robot laser treatment, electrospinning, electrospray, additive manufacturing, and radio frequency magnetron sputtering technique). Atomic-scale engineering, such as chemical vapor deposition, atomic layer etching, plasma immersion ion deposition, and atomic layer deposition, is a subsection of emerging technology that has demonstrated improved control and flexibility at finer length scales than compared to the conventional methods. With the advancements in technologies and the demand for even better control of biomaterial surfaces, research efforts in recent years are aimed at the atomic scale and molecular scale while incorporating functional agents in order to elicit optimal in situ performance. The functional agents include synthetic materials (monolithic ZnO, quaternary ammonium salts, silver nano-clusters, titanium dioxide, and graphene) and natural materials (chitosan, totarol, botanical extracts, and nisin). This review highlights the various strategies of surface engineering of biomaterial including their functional mechanism, applications, and shortcomings. Additionally, this review article emphasizes atomic scale engineering of biomaterials for fabricating antimicrobial biomaterials and explores their challenges.
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Affiliation(s)
- Afreen Sultana
- Center for Nanotechnology & Sustainability, Department of Mechanical Engineering, National University of Singapore, Singapore 117581, Singapore; (A.S.); (S.R.)
| | - Mina Zare
- Center for Nanotechnology & Sustainability, Department of Mechanical Engineering, National University of Singapore, Singapore 117581, Singapore; (A.S.); (S.R.)
| | - Hongrong Luo
- Engineering Research Center in Biomaterials, Sichuan University, Chengdu 610064, China
| | - Seeram Ramakrishna
- Center for Nanotechnology & Sustainability, Department of Mechanical Engineering, National University of Singapore, Singapore 117581, Singapore; (A.S.); (S.R.)
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9
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Evstigneeva SS, Telesheva EM, Mokeev DI, Borisov IV, Petrova LP, Shelud’ko AV. Response of Bacteria to Mechanical Stimuli. Microbiology (Reading) 2021. [DOI: 10.1134/s0026261721050052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Abstract—
Bacteria adapt rapidly to changes in ambient conditions, constantly inspecting their surroundings by means of their sensor systems. These systems are often thought to respond only to signals of a chemical nature. Yet, bacteria are often affected by mechanical forces, e.g., during transition from planktonic to sessile state. Mechanical stimuli, however, have seldom been considered as the signals bacteria can sense and respond to. Nonetheless, bacteria perceive mechanical stimuli, generate signals, and develop responses. This review analyzes the information on the way bacteria respond to mechanical stimuli and outlines how bacteria convert incoming signals into appropriate responses.
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10
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Abstract
Bacteria thrive both in liquids and attached to surfaces. The concentration of bacteria on surfaces is generally much higher than in the surrounding environment, offering bacteria ample opportunity for mutualistic, symbiotic, and pathogenic interactions. To efficiently populate surfaces, they have evolved mechanisms to sense mechanical or chemical cues upon contact with solid substrata. This is of particular importance for pathogens that interact with host tissue surfaces. In this review we discuss how bacteria are able to sense surfaces and how they use this information to adapt their physiology and behavior to this new environment. We first survey mechanosensing and chemosensing mechanisms and outline how specific macromolecular structures can inform bacteria about surfaces. We then discuss how mechanical cues are converted to biochemical signals to activate specific cellular processes in a defined chronological order and describe the role of two key second messengers, c-di-GMP and cAMP, in this process.
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Affiliation(s)
| | - Urs Jenal
- Biozentrum, University of Basel, CH-4056 Basel, Switzerland; ,
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11
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Modaresifar K, Ganjian M, Angeloni L, Minneboo M, Ghatkesar MK, Hagedoorn PL, Fratila-Apachitei LE, Zadpoor AA. On the Use of Black Ti as a Bone Substituting Biomaterial: Behind the Scenes of Dual-Functionality. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2100706. [PMID: 33978318 DOI: 10.1002/smll.202100706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/24/2021] [Indexed: 06/12/2023]
Abstract
Despite the potential of small-scale pillars of black titanium (bTi) for killing the bacteria and directing the fate of stem cells, not much is known about the effects of the pillars' design parameters on their biological properties. Here, three distinct bTi surfaces are designed and fabricated through dry etching of the titanium, each featuring different pillar designs. The interactions of the surfaces with MC3T3-E1 preosteoblast cells and Staphylococcus aureus bacteria are then investigated. Pillars with different heights and spatial organizations differently influence the morphological characteristics of the cells, including their spreading area, aspect ratio, nucleus area, and cytoskeletal organization. The preferential formation of focal adhesions (FAs) and their size variations also depend on the type of topography. When the pillars are neither fully separated nor extremely tall, the colocalization of actin fibers and FAs as well as an enhanced matrix mineralization are observed. However, the killing efficiency of these pillars against the bacteria is not as high as that of fully separated and tall pillars. This study provides a new perspective on the dual-functionality of bTi surfaces and elucidates how the surface design and fabrication parameters can be used to achieve a surface topography with balanced bactericidal and osteogenic properties.
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Affiliation(s)
- Khashayar Modaresifar
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Mekelweg 2, Delft, 2628 CD, The Netherlands
| | - Mahya Ganjian
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Mekelweg 2, Delft, 2628 CD, The Netherlands
| | - Livia Angeloni
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Mekelweg 2, Delft, 2628 CD, The Netherlands
- Department of Precision and Microsystems Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft, 2628 CD, The Netherlands
| | - Michelle Minneboo
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Mekelweg 2, Delft, 2628 CD, The Netherlands
| | - Murali K Ghatkesar
- Department of Precision and Microsystems Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft, 2628 CD, The Netherlands
| | - Peter-Leon Hagedoorn
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, Delft, 2629 HZ, The Netherlands
| | - Lidy E Fratila-Apachitei
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Mekelweg 2, Delft, 2628 CD, The Netherlands
| | - Amir A Zadpoor
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Mekelweg 2, Delft, 2628 CD, The Netherlands
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12
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Deusenbery C, Wang Y, Shukla A. Recent Innovations in Bacterial Infection Detection and Treatment. ACS Infect Dis 2021; 7:695-720. [PMID: 33733747 DOI: 10.1021/acsinfecdis.0c00890] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Bacterial infections are a major threat to human health, exacerbated by increasing antibiotic resistance. These infections can result in tremendous morbidity and mortality, emphasizing the need to identify and treat pathogenic bacteria quickly and effectively. Recent developments in detection methods have focused on electrochemical, optical, and mass-based biosensors. Advances in these systems include implementing multifunctional materials, microfluidic sampling, and portable data-processing to improve sensitivity, specificity, and ease of operation. Concurrently, advances in antibacterial treatment have largely focused on targeted and responsive delivery for both antibiotics and antibiotic alternatives. Antibiotic alternatives described here include repurposed drugs, antimicrobial peptides and polymers, nucleic acids, small molecules, living systems, and bacteriophages. Finally, closed-loop therapies are combining advances in the fields of both detection and treatment. This review provides a comprehensive summary of the current trends in detection and treatment systems for bacterial infections.
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Affiliation(s)
- Carly Deusenbery
- School of Engineering, Center for Biomedical Engineering, Institute for Molecular and Nanoscale Innovation, Brown University, Providence, Rhode Island 02912, United States
| | - Yingying Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Anita Shukla
- School of Engineering, Center for Biomedical Engineering, Institute for Molecular and Nanoscale Innovation, Brown University, Providence, Rhode Island 02912, United States
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13
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Zubareva EV, Nadezhdin SV, Nadezhdina NA, Belyaeva VS, Burda YE, Avtina TV, Gudyrev OS, Kolesnik IM, Kulikova SY, Mishenin MO. 3D organotypic cell structures for drug development and Microorganism-Host interaction research. RESEARCH RESULTS IN PHARMACOLOGY 2021. [DOI: 10.3897/rrpharmacology.7.62118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Introduction: The article describes a new method of tissue engineering, which is based on the use of three-dimensional multicellular constructs consisting of stem cells that mimic the native tissue in vivo – organoids.
3D cell cultures: The currently existing model systems of three-dimensional cultures are described.
Characteristics of organoids and strategies for their culturing: The main approaches to the fabrication of 3D cell constructs using pluripotent (embryonic and induced) stem cells or adult stem cells are described.
Brain organoids (Cerebral organoids): Organoids of the brain, which are used to study the development of the human brain, are characterized, with the description of biology of generating region-specific cerebral organoids.
Lung organoids: Approaches to the generation of lung organoids are described, by means of pluripotent stem cells and lung tissue cell lines.
Liver organoids: The features of differentiation of stem cells into hepatocyte-like cells and the creation of 3D hepatic organoids are characterized.
Intestinal organoids: The formation of small intestine organoids from stem cells is described.
Osteochondral organoids: Fabrication of osteochondral organoids is characterised.
Use of organoids as test systems for drugs screening: The information on drug screening using organoids is provided.
Using organoids to model infectious diseases and study adaptive responses of microorganisms when interacting with the host: The use of organoids for modeling infectious diseases and studying the adaptive responses of microorganisms when interacting with the host organism is described.
Conclusion: The creation of three-dimensional cell structures that reproduce the structural and functional characteristics of tissue in vivo, makes it possible to study the biology of the body’s development, the features of intercellular interactions, screening drugs and co-cultivating with viruses, bacteria and parasites.
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14
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Fajardo-Cavazos P, Nicholson WL. Mechanotransduction in Prokaryotes: A Possible Mechanism of Spaceflight Adaptation. Life (Basel) 2021; 11:33. [PMID: 33430182 PMCID: PMC7825584 DOI: 10.3390/life11010033] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/29/2020] [Accepted: 01/04/2021] [Indexed: 02/08/2023] Open
Abstract
Our understanding of the mechanisms of microgravity perception and response in prokaryotes (Bacteria and Archaea) lag behind those which have been elucidated in eukaryotic organisms. In this hypothesis paper, we: (i) review how eukaryotic cells sense and respond to microgravity using various pathways responsive to unloading of mechanical stress; (ii) we observe that prokaryotic cells possess many structures analogous to mechanosensitive structures in eukaryotes; (iii) we review current evidence indicating that prokaryotes also possess active mechanosensing and mechanotransduction mechanisms; and (iv) we propose a complete mechanotransduction model including mechanisms by which mechanical signals may be transduced to the gene expression apparatus through alterations in bacterial nucleoid architecture, DNA supercoiling, and epigenetic pathways.
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Affiliation(s)
| | - Wayne L. Nicholson
- Space Life Sciences Laboratory, Department of Microbiology and Cell Science, University of Florida, 505 Odyssey Way, Merritt Island, FL 32953, USA;
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15
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Zhu J, Wang M, Zhang H, Yang S, Song KY, Yin R, Zhang W. Effects of Hydrophilicity, Adhesion Work, and Fluid Flow on Biofilm Formation of PDMS in Microfluidic Systems. ACS APPLIED BIO MATERIALS 2020; 3:8386-8394. [PMID: 35019610 DOI: 10.1021/acsabm.0c00660] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polydimethylsiloxane (PDMS) has been the most widely used material in microfluidic systems, especially for cell biology applications. However, the antibacterial performance of PDMS in flow conditions has never been reported in the literature. In this paper, we analyzed the effects of contact angle (CA), adhesion force (work), and surface free energy on the antibacterial activities of PDMS by varying the ratio of curing agents (crosslinking degree) and surface modification with oxygen plasma. The results show that the Young's modulus has no particular effects on bacterial adhesion compared to the CAs of samples. For the first time, we analyzed the adhesion work (AW) effect on biofilm formation, and we found that biofilms tend to form on the surface with less AW. Furthermore, we analyzed the dual effect of hydrophilicity and shear force induced by fluid flow on the bacterial adhesion in PDMS microfluidic systems. We found that at low flow rates in microfluidic conditions, the adhesion of the bacteria on the PDMS surface is inhibited when the fluid flow exceeds a certain value. It required higher shear force to inhibit bacterial adhesion on the hydrophilic surface than on the hydrophobic surface. Therefore, hydrophilicity might be the dominant factor affecting bacterial adhesion.
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Affiliation(s)
- Jinling Zhu
- School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Minqi Wang
- Shanghai Jiaotong University, 9th hospital, Shanghai 200011, China
| | - Hongbo Zhang
- School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Shengbing Yang
- Shanghai Jiaotong University, 9th hospital, Shanghai 200011, China
| | - Ki-Young Song
- School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100811, China
| | - Ruixue Yin
- School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Wenjun Zhang
- School of Mechatronics and Automation, Shanghai University, Shanghai 200240, China.,College of Engineering, The University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A9, Canada
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16
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Liu J, Liu J, Attarilar S, Wang C, Tamaddon M, Yang C, Xie K, Yao J, Wang L, Liu C, Tang Y. Nano-Modified Titanium Implant Materials: A Way Toward Improved Antibacterial Properties. Front Bioeng Biotechnol 2020; 8:576969. [PMID: 33330415 PMCID: PMC7719827 DOI: 10.3389/fbioe.2020.576969] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 10/22/2020] [Indexed: 01/01/2023] Open
Abstract
Titanium and its alloys have superb biocompatibility, low elastic modulus, and favorable corrosion resistance. These exceptional properties lead to its wide use as a medical implant material. Titanium itself does not have antibacterial properties, so bacteria can gather and adhere to its surface resulting in infection issues. The infection is among the main reasons for implant failure in orthopedic surgeries. Nano-modification, as one of the good options, has the potential to induce different degrees of antibacterial effect on the surface of implant materials. At the same time, the nano-modification procedure and the produced nanostructures should not adversely affect the osteogenic activity, and it should simultaneously lead to favorable antibacterial properties on the surface of the implant. This article scrutinizes and deals with the surface nano-modification of titanium implant materials from three aspects: nanostructures formation procedures, nanomaterials loading, and nano-morphology. In this regard, the research progress on the antibacterial properties of various surface nano-modification of titanium implant materials and the related procedures are introduced, and the new trends will be discussed in order to improve the related materials and methods.
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Affiliation(s)
- Jianqiao Liu
- Department of Orthopaedics, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
- Youjiang Medical University for Nationalities, Baise, China
| | - Jia Liu
- Department of Orthopaedics, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
| | - Shokouh Attarilar
- Department of Pediatric Orthopaedics, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Chong Wang
- College of Mechanical Engineering, Dongguan University of Technology, Dongguan, China
| | - Maryam Tamaddon
- Institute of Orthopaedic and Musculoskeletal Science, Division of Surgery & Orthopaedic Science, University College London, The Royal National National Orthopaedic Hospital, Stanmore, United Kingdom
| | - Chengliang Yang
- Department of Orthopaedics, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
| | - Kegong Xie
- Department of Orthopaedics, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
| | - Jinguang Yao
- Youjiang Medical University for Nationalities, Baise, China
| | - Liqiang Wang
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Chaozong Liu
- Institute of Orthopaedic and Musculoskeletal Science, Division of Surgery & Orthopaedic Science, University College London, The Royal National National Orthopaedic Hospital, Stanmore, United Kingdom
| | - Yujin Tang
- Department of Orthopaedics, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
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17
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Tsata V, Beis D. In Full Force. Mechanotransduction and Morphogenesis during Homeostasis and Tissue Regeneration. J Cardiovasc Dev Dis 2020; 7:jcdd7040040. [PMID: 33019569 PMCID: PMC7711708 DOI: 10.3390/jcdd7040040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/17/2020] [Accepted: 09/25/2020] [Indexed: 12/21/2022] Open
Abstract
The interactions of form and function have been the focus of numerous studies in the context of development and more recently regeneration. Our understanding on how cells, tissues and organs sense and interpret external cues, such as mechanical forces, is becoming deeper as novel techniques in imaging are applied and the relevant signaling pathways emerge. These cellular responses can be found from bacteria to all multicellular organisms such as plants and animals. In this review, we focus on hemodynamic flow and endothelial shear stress during cardiovascular development and regeneration, where the interactions of morphogenesis and proper function are more prominent. In addition, we address the recent literature on the role of extracellular matrix and fibrotic response during tissue repair and regeneration. Finally, we refer to examples where the integration of multi-disciplinary approaches to understand the biomechanics of cellular responses could be utilized in novel medical applications.
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Affiliation(s)
- Vasiliki Tsata
- Correspondence: (V.T.); (D.B.); Tel.: +3021-0659-7439 (V.T. & D.B.)
| | - Dimitris Beis
- Correspondence: (V.T.); (D.B.); Tel.: +3021-0659-7439 (V.T. & D.B.)
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18
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Poberezhnyi V, Marchuk O, Katilov O, Shvydiuk O, Lohvinov O. Basic concepts and physical-chemical phenomena, that have conceptual meaning for the formation of systemic clinical thinking and formalization of the knowledge of systemic structural-functional organization of the human’s organism. PAIN MEDICINE 2020. [DOI: 10.31636/pmjua.v5i2.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
From the point of view of perception and generalization processes there are complex, logic and conceptual forms of thinking. Its conceptual form is the highest result of interaction between thinking and speech. While realizing it, human uses the concept, which are logically formed thoughts, that are the meaning of representation in thinking of unity of meaningful features, relations of subjects or phenomena of objective reality. Special concepts, that are used in the science and technique are called terms. They perform a function of corresponding, special, precise marking of subjects and phenomena, their features and interactions. Scientific knowledge are in that way an objective representation of material duality in our consciousness. Certain complex of terms forms a terminological system, that lies in the basis of corresponding sphere of scientific knowledge and conditions a corresponding form and way of thinking. Clinical thinking is a conceptual form, that manifests and represents by the specialized internal speech with gnostic motivation lying in its basis. Its structural elements are corresponding definitions, terms and concepts. Cardinal features of clinical systems are consistency, criticality, justification and substantiation. Principles of perception and main concepts are represented in the article along with short descriptions of physical and chemical phenomena, that have conceptual meaning for the formation of systematic clinical thinking and formalization of systemic structural-functional organization of the human’s organism
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19
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The E. coli transcription factor GrlA is regulated by subcellular compartmentalization and activated in response to mechanical stimuli. Proc Natl Acad Sci U S A 2020; 117:9519-9528. [PMID: 32277032 DOI: 10.1073/pnas.1917500117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) is a foodborne pathogen that colonizes the gastrointestinal tract and has evolved intricate mechanisms to sense and respond to the host environment. Upon the sensation of chemical and physical cues specific to the host's intestinal environment, locus of enterocyte effacement (LEE)-encoded virulence genes are activated and promote intestinal colonization. The LEE transcriptional activator GrlA mediates EHEC's response to mechanical cues characteristic of the intestinal niche, including adhesive force that results from bacterial adherence to epithelial cells and fluid shear that results from intestinal motility and transit. GrlA expression and release from its inhibitor GrlR was not sufficient to induce virulence gene transcription; mechanical stimuli were required for GrlA activation. The exact mechanism of GrlA activation, however, remained unknown. We isolated GrlA mutants that activate LEE transcription, independent of applied mechanical stimuli. In nonstimulated EHEC, wild-type GrlA associates with cardiolipin membrane domains via a patch of basic C-terminal residues, and this membrane sequestration is disrupted in EHEC that expresses constitutively active GrlA mutants. GrlA transitions from an inactive, membrane-associated state and relocalizes to the cytoplasm in response to mechanical stimuli, allowing GrlA to bind and activate the LEE1 promoter. GrlA expression and its relocalization in response to mechanical stimuli are required for optimal virulence regulation and colonization of the host intestinal tract during infection. These data suggest a posttranslational regulatory mechanism of the mechanosensor GrlA, whereby virulence gene expression can be rapidly fine-tuned in response to the highly dynamic spatiotemporal mechanical profile of the gastrointestinal tract.
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20
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Abstract
The bacterial cell envelope is essential for viability, the environmental gatekeeper and first line of defense against external stresses. For most bacteria, the envelope biosynthesis is also the site of action of some of the most important groups of antibiotics. It is a complex, often multicomponent structure, able to withstand the internally generated turgor pressure. Thus, elucidating the architecture and dynamics of the cell envelope is important, to unravel not only the complexities of cell morphology and maintenance of integrity but also how interventions such as antibiotics lead to death. To address these questions requires the capacity to visualize the cell envelope in situ via high-spatial resolution approaches. In recent years, atomic force microscopy (AFM) has brought novel molecular insights into the assembly, dynamics, and functions of bacterial cell envelopes. The ultrafine resolution and physical sensitivity of the technique have revealed a wealth of ultrastructural features that are invisible to traditional optical microscopy techniques or imperceptible in their true physiological state by electron microscopy. Here, we discuss recent progress in our use of AFM imaging for understanding the architecture and dynamics of the bacterial envelope. We survey recent studies that demonstrate the power of the technique to observe isolated membranes and live cells at (sub)nanometer resolution and under physiological conditions and to track in vitro structural dynamics in response to growth or to drugs.
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21
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Modaresifar K, Kunkels LB, Ganjian M, Tümer N, Hagen CW, Otten LG, Hagedoorn PL, Angeloni L, Ghatkesar MK, Fratila-Apachitei LE, Zadpoor AA. Deciphering the Roles of Interspace and Controlled Disorder in the Bactericidal Properties of Nanopatterns against Staphylococcus aureus. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E347. [PMID: 32085452 PMCID: PMC7075137 DOI: 10.3390/nano10020347] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/07/2020] [Accepted: 02/12/2020] [Indexed: 02/06/2023]
Abstract
Recent progress in nano-/micro-fabrication techniques has paved the way for the emergence of synthetic bactericidal patterned surfaces that are capable of killing the bacteria via mechanical mechanisms. Different design parameters are known to affect the bactericidal activity of nanopatterns. Evaluating the effects of each parameter, isolated from the others, requires systematic studies. Here, we systematically assessed the effects of the interspacing and disordered arrangement of nanopillars on the bactericidal properties of nanopatterned surfaces. Electron beam induced deposition (EBID) was used to additively manufacture nanopatterns with precisely controlled dimensions (i.e., a height of 190 nm, a diameter of 80 nm, and interspaces of 100, 170, 300, and 500 nm) as well as disordered versions of them. The killing efficiency of the nanopatterns against Gram-positive Staphylococcus aureus bacteria increased by decreasing the interspace, achieving the highest efficiency of 62 ± 23% on the nanopatterns with 100 nm interspacing. By comparison, the disordered nanopatterns did not influence the killing efficiency significantly, as compared to their ordered correspondents. Direct penetration of nanopatterns into the bacterial cell wall was identified as the killing mechanism according to cross-sectional views, which is consistent with previous studies. The findings indicate that future studies aimed at optimizing the design of nanopatterns should focus on the interspacing as an important parameter affecting the bactericidal properties. In combination with controlled disorder, nanopatterns with contrary effects on bacterial and mammalian cells may be developed.
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Affiliation(s)
- Khashayar Modaresifar
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands (L.A.)
| | - Lorenzo B. Kunkels
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands (L.A.)
| | - Mahya Ganjian
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands (L.A.)
| | - Nazli Tümer
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands (L.A.)
| | - Cornelis W. Hagen
- Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, 2628CJ Delft, The Netherlands
| | - Linda G. Otten
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, 2626HZ Delft, The Netherlands
| | - Peter-Leon Hagedoorn
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, 2626HZ Delft, The Netherlands
| | - Livia Angeloni
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands (L.A.)
- Department of Precision and Microsystems Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands;
| | - Murali K. Ghatkesar
- Department of Precision and Microsystems Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands;
| | - Lidy E. Fratila-Apachitei
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands (L.A.)
| | - Amir A. Zadpoor
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands (L.A.)
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22
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Tan CAZ, Antypas H, Kline KA. Overcoming the challenge of establishing biofilms in vivo: a roadmap for Enterococci. Curr Opin Microbiol 2020; 53:9-18. [PMID: 32062025 DOI: 10.1016/j.mib.2020.01.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/10/2020] [Accepted: 01/15/2020] [Indexed: 12/28/2022]
Abstract
Enterococcus faecalis forms single and mixed-species biofilms on both tissue and medical devices in the host, often under exposure to fluid flow, giving rise to infections that are recalcitrant to treatment. The factors that drive enterococcal biofilm formation in the host, however, remain unclear. Recent reports in other pathogens show how surface sensing by bacteria can trigger the transition from planktonic to sessile lifestyle. Fluid flow can enhance initial adhesion, but also influence quorum sensing. Biofilm-specific factors, as well as biofilm size and extracellular polymeric substances, can compromise opsonization and phagocytosis. Bacterial interspecies synergy can create favorable conditions in the host for biofilm formation. Through these concepts, we define the knowledge gaps in understanding host-associated E. faecalis biofilm formation and propose a roadmap for future investigations.
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Affiliation(s)
- Casandra Ai Zhu Tan
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Haris Antypas
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Kimberly A Kline
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore.
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23
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Mechanomicrobiology: how bacteria sense and respond to forces. Nat Rev Microbiol 2020; 18:227-240. [DOI: 10.1038/s41579-019-0314-2] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2019] [Indexed: 12/26/2022]
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24
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Nord AL, Pedaci F. Mechanisms and Dynamics of the Bacterial Flagellar Motor. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1267:81-100. [PMID: 32894478 DOI: 10.1007/978-3-030-46886-6_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Many bacteria are able to actively propel themselves through their complex environment, in search of resources and suitable niches. The source of this propulsion is the Bacterial Flagellar Motor (BFM), a molecular complex embedded in the bacterial membrane which rotates a flagellum. In this chapter we review the known physical mechanisms at work in the motor. The BFM shows a highly dynamic behavior in its power output, its structure, and in the stoichiometry of its components. Changes in speed, rotation direction, constituent protein conformations, and the number of constituent subunits are dynamically controlled in accordance to external chemical and mechanical cues. The mechano-sensitivity of the motor is likely related to the surface-sensing ability of bacteria, relevant in the initial stage of biofilm formation.
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Affiliation(s)
- A L Nord
- Centre de Biochimie Structurale (CBS), INSERM, CNRS, University of Montpellier, Montpellier, France
| | - F Pedaci
- Centre de Biochimie Structurale (CBS), INSERM, CNRS, University of Montpellier, Montpellier, France.
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Belin BJ, Tookmanian EM, de Anda J, Wong GCL, Newman DK. Extended Hopanoid Loss Reduces Bacterial Motility and Surface Attachment and Leads to Heterogeneity in Root Nodule Growth Kinetics in a Bradyrhizobium-Aeschynomene Symbiosis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:1415-1428. [PMID: 31170026 PMCID: PMC7583662 DOI: 10.1094/mpmi-04-19-0111-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Hopanoids are steroid-like bacterial lipids that enhance membrane rigidity and promote bacterial growth under diverse stresses. Hopanoid biosynthesis genes are conserved in nitrogen-fixing plant symbionts, and we previously found that the extended (C35) class of hopanoids in Bradyrhizobium diazoefficiens are required for efficient symbiotic nitrogen fixation in the tropical legume host Aeschynomene afraspera. Here, we demonstrate that the nitrogen-fixation defect conferred by extended hopanoid loss can be fully explained by a reduction in root nodule sizes rather than per-bacteroid nitrogen-fixation levels. Using a single-nodule tracking approach to quantify A. afraspera nodule development, we provide a quantitative model of root nodule development in this host, uncovering both the baseline growth parameters for wild-type nodules and a surprising heterogeneity of extended hopanoid mutant developmental phenotypes. These phenotypes include a delay in root nodule initiation and the presence of a subpopulation of nodules with slow growth rates and low final volumes, which are correlated with reduced motility and surface attachment in vitro and lower bacteroid densities in planta, respectively. This work provides a quantitative reference point for understanding the phenotypic diversity of ineffective symbionts in A. afraspera and identifies specific developmental stages affected by extended hopanoid loss for future mechanistic work.
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Affiliation(s)
- Brittany J. Belin
- Division of Biology & Bioengineering, California Institute of Technology, Pasadena, CA, U.S.A
| | - Elise M. Tookmanian
- Division of Chemistry & Chemical Engineering, California Institute of Technology
| | - Jaime de Anda
- Department of Bioengineering, Department of Chemistry and Biochemistry, and California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, U.S.A
| | - Gerard C. L. Wong
- Division of Geological & Planetary Sciences, California Institute of Technology
| | - Dianne K. Newman
- Division of Biology & Bioengineering, California Institute of Technology, Pasadena, CA, U.S.A
- Division of Geological & Planetary Sciences, California Institute of Technology
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Pore-scale hydrodynamics influence the spatial evolution of bacterial biofilms in a microfluidic porous network. PLoS One 2019; 14:e0218316. [PMID: 31246972 PMCID: PMC6597062 DOI: 10.1371/journal.pone.0218316] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 05/31/2019] [Indexed: 12/31/2022] Open
Abstract
Bacteria occupy heterogeneous environments, attaching and growing within pores in materials, living hosts, and matrices like soil. Systems that permit high-resolution visualization of dynamic bacterial processes within the physical confines of a realistic and tractable porous media environment are rare. Here we use microfluidics to replicate the grain shape and packing density of natural sands in a 2D platform to study the flow-induced spatial evolution of bacterial biofilms underground. We discover that initial bacterial dispersal and grain attachment is influenced by bacterial transport across pore space velocity gradients, a phenomenon otherwise known as rheotaxis. We find that gravity-driven flow conditions activate different bacterial cell-clustering phenotypes depending on the strain's ability to product extracellular polymeric substances (EPS). A wildtype, biofilm-producing bacteria formed compact, multicellular patches while an EPS-defective mutant displayed a linked-cell phenotype in the presence of flow. These phenotypes subsequently influenced the overall spatial distribution of cells across the porous media network as colonies grew and altered the fluid dynamics of their microenvironment.
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Cell Shape and Population Migration Are Distinct Steps of Proteus mirabilis Swarming That Are Decoupled on High-Percentage Agar. J Bacteriol 2019; 201:JB.00726-18. [PMID: 30858303 DOI: 10.1128/jb.00726-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/08/2019] [Indexed: 01/10/2023] Open
Abstract
Swarming on rigid surfaces requires movement of cells as individuals and as a group of cells. For the bacterium Proteus mirabilis, an individual cell can respond to a rigid surface by elongating and migrating over micrometer-scale distances. Cells can form groups of transiently aligned cells, and the collective population is capable of migrating over centimeter-scale distances. To address how P. mirabilis populations swarm on rigid surfaces, we asked whether cell elongation and single-cell motility are coupled to population migration. We first measured the relationship between agar concentration (a proxy for surface rigidity), single-cell phenotypes, and swarm colony phenotypes. We find that cell elongation and single-cell motility are coupled with population migration on low-percentage hard agar (1% to 2.5%) and become decoupled on high-percentage hard agar (>2.5%). Next, we evaluate how disruptions in lipopolysaccharide (LPS), specifically the O-antigen components, affect responses to hard agar. We find that LPS is not essential for elongation and motility of individual cells, as predicted, and instead functions to broaden the range of agar concentrations on which cell elongation and motility are coupled with population migration. These findings demonstrate that cell elongation and motility are coupled with population migration under a permissive range of surface conditions; increasing agar concentration is sufficient to decouple these behaviors. Since swarm colonies cover greater distances when these steps are coupled than when they are not, these findings suggest that collective interactions among P. mirabilis cells might be emerging as a colony expands outwards on rigid surfaces.IMPORTANCE How surfaces influence cell size, cell-cell interactions, and population migration for robust swarmers like P. mirabilis is not fully understood. Here, we have elucidated how cells change length along a spectrum of sizes that positively correlates with increases in agar concentration, regardless of population migration. Single-cell phenotypes can be decoupled from collective population migration simply by increasing agar concentration. A cell's lipopolysaccharides function to broaden the range of agar conditions under which cell elongation and single-cell motility remain coupled with population migration. In eukaryotes, the physical environment, such as a surface matrix, can impact cell development, shape, and migration. These findings support the idea that rigid surfaces similarly act on swarming bacteria to impact cell shape, single-cell motility, and collective population migration.
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Gordon VD, Wang L. Bacterial mechanosensing: the force will be with you, always. J Cell Sci 2019; 132:132/7/jcs227694. [PMID: 30944157 DOI: 10.1242/jcs.227694] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Whether bacteria are in the planktonic state, free-swimming or free-floating in liquid, or in the biofilm state, sessile on surfaces, they are always subject to mechanical forces. The long, successful evolutionary history of bacteria implies that they are capable of adapting to varied mechanical forces, and probably even actively respond to mechanical cues in their changing environments. However, the sensing of mechanical cues by bacteria, or bacterial mechanosensing, has been under-investigated. This leaves the mechanisms underlying how bacteria perceive and respond to mechanical cues largely unknown. In this Review, we first examine the surface-associated behavior of bacteria, outline the clear evidence for bacterial mechanosensing and summarize the role of flagella, type-IV pili, and envelope proteins as potential mechanosensors, before presenting indirect evidence for mechanosensing in bacteria. The general themes underlying bacterial mechanosensing that we highlight here may provide a framework for future research.
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Affiliation(s)
- Vernita D Gordon
- Department of Physics and Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX 78712, USA .,Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Liyun Wang
- Department of Physics and Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX 78712, USA
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Straub H, Bigger CM, Valentin J, Abt D, Qin X, Eberl L, Maniura‐Weber K, Ren Q. Bacterial Adhesion on Soft Materials: Passive Physicochemical Interactions or Active Bacterial Mechanosensing? Adv Healthc Mater 2019; 8:e1801323. [PMID: 30773835 DOI: 10.1002/adhm.201801323] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 01/27/2019] [Indexed: 11/08/2022]
Abstract
The influence of mechanical stiffness of biomaterials on bacterial adhesion is only sparsely studied and the mechanism behind this influence remains unclear. Here, bacterial adhesion on polydimethylsiloxane (PDMS) samples, having four different degrees of stiffness with Young's modulus ranging from 0.06 to 4.52 MPa, is investigated. Escherichia coli and Pseudomonas aeruginosa are found to adhere in greater numbers on soft PDMS (7- and 27-fold increase, respectively) than on stiff PDMS, whereas Staphylococcus aureus adheres in similar numbers on the four tested surfaces. To determine whether the observed adhesion behavior is caused by bacteria-specific mechanisms, abiotic polystyrene (PS) beads are employed as bacteria substitutes. Carboxylate-modified PS (PS-COOH) beads exhibit the same adhesion pattern as E. coli and P. aeruginosa with four times more adhered beads on soft PDMS than on stiff PDMS. In contrast, amine-modified PS (PS-NH2 ) beads adhere in similar numbers on all tested samples, reminiscent of S. aureus adhesion. This work demonstrates for the first time that the intrinsic physicochemical properties associated with PDMS substrates of different stiffness strongly influence bacterial adhesion and challenge the previously reported theory on active bacterial mechanosensing, which provides new insights into the design of antifouling surfaces.
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Affiliation(s)
- Hervé Straub
- Laboratory for BiointerfacesEmpa, Swiss Federal Laboratories for Materials Science & Technology Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
| | - Claudio M. Bigger
- Laboratory for BiointerfacesEmpa, Swiss Federal Laboratories for Materials Science & Technology Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
| | - Jules Valentin
- Laboratory for BiointerfacesEmpa, Swiss Federal Laboratories for Materials Science & Technology Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
| | - Dominik Abt
- Department of UrologyCantonal Hospital St. Gallen Rorschacher Strasse 95 9007 St. Gallen Switzerland
| | - Xiao‐Hua Qin
- Institute for Biomechanics ETH Zürich Leopold‐Ruzicka‐Weg 4 8093 Zürich Switzerland
| | - Leo Eberl
- Department of Plant and Microbial BiologyUniversity of Zürich Zollikerstrasse 107 8008 Zürich Switzerland
| | - Katharina Maniura‐Weber
- Laboratory for BiointerfacesEmpa, Swiss Federal Laboratories for Materials Science & Technology Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
| | - Qun Ren
- Laboratory for BiointerfacesEmpa, Swiss Federal Laboratories for Materials Science & Technology Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
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Pseudomonas aeruginosa orchestrates twitching motility by sequential control of type IV pili movements. Nat Microbiol 2019; 4:774-780. [PMID: 30804544 DOI: 10.1038/s41564-019-0378-9] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 01/18/2019] [Indexed: 11/08/2022]
Abstract
Prokaryotes have the ability to walk on surfaces using type IV pili (TFP), a motility mechanism known as twitching1,2. Molecular motors drive TFP extension and retraction, but whether and how these movements are coordinated is unknown3. Here, we reveal how the pathogen Pseudomonas aeruginosa coordinates the motorized activity of TFP to power efficient surface motility. To do this, we dynamically visualized TFP extension, attachment and retraction events at high resolution in four dimensions using label-free interferometric scattering microscopy (iSCAT)4. By measuring TFP dynamics, we found that the retraction motor PilT was sufficient to generate tension and power motility in free solution, while its partner ATPase PilU may improve retraction only in high-friction environments. Using precise timing of successive attachment and retraction, we show that P. aeruginosa engages PilT motors very rapidly and almost only when TFP encounter the surface, suggesting contact sensing. Finally, measurements of TFP dwell times on surfaces show that tension reinforced the adhesion strength to the surface of individual pili, thereby increasing effective pulling time during retraction. The successive control of TFP extension, attachment, retraction and detachment suggests that sequential control of motility machinery is a conserved strategy for optimized locomotion across domains of life.
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Bactericidal effects of nanopatterns: A systematic review. Acta Biomater 2019; 83:29-36. [PMID: 30273746 DOI: 10.1016/j.actbio.2018.09.059] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 09/01/2018] [Accepted: 09/27/2018] [Indexed: 12/27/2022]
Abstract
We systematically reviewed the currently available evidence on how the design parameters of surface nanopatterns (e.g. height, diameter, and interspacing) relate to their bactericidal behavior. The systematic search of the literature resulted in 46 studies that satisfied the inclusion criteria of examining the bactericidal behavior of nanopatterns with known design parameters in absence of antibacterial agents. Twelve of the included studies also assessed the cytocompatibility of the nanopatterns. Natural and synthetic nanopatterns with a wide range of design parameters were reported in the included studies to exhibit bactericidal behavior. However, most design parameters were in the following ranges: heights of 100-1000 nm, diameters of 10-300 nm, and interspacings of <500 nm. The most commonly used type of nanopatterns were nanopillars, which could kill bacteria in the following range of design parameters: heights of 100-900 nm, diameters of 20-207 nm, and interspacings of 9-380 nm. The vast majority of the cytocompatibility studies (11 out of 12) showed no adverse effects of bactericidal nanopatterns with the only exception being nanopatterns with extremely high aspect ratios. The paper concludes with a discussion on the evidence available in the literature regarding the killing mechanisms of nanopatterns and the effects of other parameters including surface affinity of bacteria, cell size, and extracellular polymeric substance (EPS) on the killing efficiency. STATEMENT OF SIGNIFICANCE: The use of nanopatterns to kill bacteria without the need for antibiotics represents a rapidly growing area of research. However, the optimum design parameters to maximize the bactericidal behavior of such physical features need to be fully identified. The present manuscript provides a systematic review of the bactericidal nanopatterned surfaces. Identifying the effective range of dimensions in terms of height, diameter, and interspacings, as well as covering their impact on mammalian cells, has enabled a comprehensive discussion including the bactericidal mechanisms and the factors controlling the bactericidal efficiency. Overall, this review helps the readers have a better understanding of the state-of-the-art in the design of bactericidal nanopatterns, serving as a design guideline and contributing to the design of future experimental studies.
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Kimkes TEP, Heinemann M. Reassessing the role of the Escherichia coli CpxAR system in sensing surface contact. PLoS One 2018; 13:e0207181. [PMID: 30412611 PMCID: PMC6226299 DOI: 10.1371/journal.pone.0207181] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 10/29/2018] [Indexed: 12/23/2022] Open
Abstract
For proper biofilm formation, bacteria must have mechanisms in place to sense adhesion to surfaces. In Escherichia coli, the CpxAR and RcsCDB systems have been reported to sense surfaces. The CpxAR system is widely considered to be responsible for sensing attachment, specifically to hydrophobic surfaces. Here, using both single-cell and population-level analyses, we confirm RcsCDB activation upon surface contact, but find that the CpxAR system is not activated, in contrast to what had earlier been reported. Thus, the role of CpxAR in surface sensing and initiation of biofilm formation should be reconsidered.
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Affiliation(s)
- Tom E. P. Kimkes
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Matthias Heinemann
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
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Modeling Host-Pathogen Interactions in the Context of the Microenvironment: Three-Dimensional Cell Culture Comes of Age. Infect Immun 2018; 86:IAI.00282-18. [PMID: 30181350 DOI: 10.1128/iai.00282-18] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Tissues and organs provide the structural and biochemical landscapes upon which microbial pathogens and commensals function to regulate health and disease. While flat two-dimensional (2-D) monolayers composed of a single cell type have provided important insight into understanding host-pathogen interactions and infectious disease mechanisms, these reductionist models lack many essential features present in the native host microenvironment that are known to regulate infection, including three-dimensional (3-D) architecture, multicellular complexity, commensal microbiota, gas exchange and nutrient gradients, and physiologically relevant biomechanical forces (e.g., fluid shear, stretch, compression). A major challenge in tissue engineering for infectious disease research is recreating this dynamic 3-D microenvironment (biological, chemical, and physical/mechanical) to more accurately model the initiation and progression of host-pathogen interactions in the laboratory. Here we review selected 3-D models of human intestinal mucosa, which represent a major portal of entry for infectious pathogens and an important niche for commensal microbiota. We highlight seminal studies that have used these models to interrogate host-pathogen interactions and infectious disease mechanisms, and we present this literature in the appropriate historical context. Models discussed include 3-D organotypic cultures engineered in the rotating wall vessel (RWV) bioreactor, extracellular matrix (ECM)-embedded/organoid models, and organ-on-a-chip (OAC) models. Collectively, these technologies provide a more physiologically relevant and predictive framework for investigating infectious disease mechanisms and antimicrobial therapies at the intersection of the host, microbe, and their local microenvironments.
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Berne C, Ellison CK, Ducret A, Brun YV. Bacterial adhesion at the single-cell level. Nat Rev Microbiol 2018; 16:616-627. [DOI: 10.1038/s41579-018-0057-5] [Citation(s) in RCA: 266] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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35
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Chevalier S, Bouffartigues E, Bazire A, Tahrioui A, Duchesne R, Tortuel D, Maillot O, Clamens T, Orange N, Feuilloley MGJ, Lesouhaitier O, Dufour A, Cornelis P. Extracytoplasmic function sigma factors in Pseudomonas aeruginosa. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:706-721. [PMID: 29729420 DOI: 10.1016/j.bbagrm.2018.04.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/06/2018] [Accepted: 04/30/2018] [Indexed: 01/26/2023]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa, like all members of the genus Pseudomonas, has the capacity to thrive in very different environments, ranging from water, plant roots, to animals, including humans to whom it can cause severe infections. This remarkable adaptability is reflected in the number of transcriptional regulators, including sigma factors in this bacterium. Among those, the 19 to 21 extracytoplasmic sigma factors (ECFσ) are endowed with different regulons and functions, including the iron starvation σ (PvdS, FpvI, HasI, FecI, FecI2 and others), the cell wall stress ECFσ AlgU, SigX and SbrI, and the unorthodox σVreI involved in the expression of virulence. Recently published data show that these ECFσ have separate regulons although presenting some cross-talk. We will present evidence that these different ECFσ are involved in the expression of different phenotypes, ranging from cell-wall stress response, production of extracellular polysaccharides, formation of biofilms, to iron acquisition.
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Affiliation(s)
- Sylvie Chevalier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France.
| | - Emeline Bouffartigues
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Alexis Bazire
- IUEM, Université de Bretagne-Sud (UBL), Laboratoire de Biotechnologie et Chimie Marines EA 3884, Lorient, France
| | - Ali Tahrioui
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Rachel Duchesne
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Damien Tortuel
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Olivier Maillot
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Thomas Clamens
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Nicole Orange
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Marc G J Feuilloley
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Olivier Lesouhaitier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Alain Dufour
- IUEM, Université de Bretagne-Sud (UBL), Laboratoire de Biotechnologie et Chimie Marines EA 3884, Lorient, France
| | - Pierre Cornelis
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
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Viela F, Navarro-Baena I, Hernández JJ, Osorio MR, Rodríguez I. Moth-eye mimetic cytocompatible bactericidal nanotopography: a convergent design. BIOINSPIRATION & BIOMIMETICS 2018; 13:026011. [PMID: 29350201 DOI: 10.1088/1748-3190/aaa903] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The rapid emergence of antibiotic resistant bacteria has prompted the need for radically different approaches to combat bacterial infections. Among these, bioinspired surface topographies have emerged as an effective sustainable strategy to deter bacterial infection. This study demonstrates the bactericidal activity and cytocompatibility of the moth-eye mimetic topography produced by thermal polymer nanoimprinting. The moth-eye topography was found to have bactericidal capabilities against Gram negative and Gram positive bacteria. Electron microscopy imaging revealed the bactericidal effect caused by mechanical rupture of the bacteria wall inflicted by the topography on the adhered cells. The cytocompatibility of the surfaces was evidenced by assessing the proliferation and morphology of keratinocytes cultured on the nanotopography. The technology meets important needs in medical implant technology for materials that not only have good biocompatibility but also antibacterial properties for reducing the risk of infections and related health complications.
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Affiliation(s)
- Felipe Viela
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanoscience), C/Faraday 9, Ciudad Universitaria de Cantoblanco, Madrid 28049, Spain
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Abstract
Bacteria represent one of the most evolutionarily successful groups of organisms to inhabit Earth. Their world is awash with mechanical cues, probably the most ancient form of which are osmotic forces. As a result, they have developed highly robust mechanosensors in the form of bacterial mechanosensitive (MS) channels. These channels are essential in osmoregulation, and in this setting, provide one of the simplest paradigms for the study of mechanosensory transduction. We explore the past, present, and future of bacterial MS channels, including the alternate mechanosensory roles that they may play in complex microbial communities. Central to all of these functions is their ability to change conformation in response to mechanical stimuli. We discuss their gating according to the force-from-lipids principle and its applicability to eukaryotic MS channels. This includes the new paradigms emerging for bilayer-mediated channel mechanosensitivity and how this molecular detail may provide advances in both industry and medicine.
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Affiliation(s)
- Charles D Cox
- Victor Chang Cardiac Research Institute, Sydney, New South Wales 2010, Australia; , , .,St. Vincent's Clinical School, University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Navid Bavi
- Victor Chang Cardiac Research Institute, Sydney, New South Wales 2010, Australia; , , .,St. Vincent's Clinical School, University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Sydney, New South Wales 2010, Australia; , , .,St. Vincent's Clinical School, University of New South Wales, Sydney, New South Wales 2010, Australia
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