1
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Peng Y, Chen B. Role of cell membrane homeostasis in the pathogenicity of pathogenic filamentous fungi. Virulence 2024; 15:2299183. [PMID: 38156783 PMCID: PMC10761126 DOI: 10.1080/21505594.2023.2299183] [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: 08/27/2023] [Accepted: 12/20/2023] [Indexed: 01/03/2024] Open
Abstract
The cell membrane forms a fundamental part of all living cells and participates in a variety of physiological processes, such as material exchange, stress response, cell recognition, signal transduction, cellular immunity, apoptosis, and pathogenicity. Here, we review the mechanisms and functions of the membrane structure (lipid components of the membrane and the biosynthesis of unsaturated fatty acids), membrane proteins (transmembrane proteins and proteins contributing to membrane curvature), transcriptional regulation, and cell wall components that influence the virulence and pathogenicity of filamentous fungi.
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Affiliation(s)
- Yuejin Peng
- Yunnan State Key Laboratory of Conservation and Utilization of Biological Resources, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Bin Chen
- Yunnan State Key Laboratory of Conservation and Utilization of Biological Resources, Yunnan Agricultural University, Kunming, Yunnan, China
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2
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Brissac T, Guyonnet C, Sadouni A, Hernández-Montoya A, Jacquemet E, Legendre R, Sismeiro O, Trieu-Cuot P, Lanotte P, Tazi A, Firon A. Coordinated regulation of osmotic imbalance by c-di-AMP shapes ß-lactam tolerance in Group B Streptococcus. MICROLIFE 2024; 5:uqae014. [PMID: 38993744 PMCID: PMC11238645 DOI: 10.1093/femsml/uqae014] [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] [Received: 05/06/2024] [Revised: 06/03/2024] [Accepted: 06/11/2024] [Indexed: 07/13/2024]
Abstract
Streptococcus agalactiae is among the few pathogens that have not developed resistance to ß-lactam antibiotics despite decades of clinical use. The molecular basis of this long-lasting susceptibility has not been investigated, and it is not known whether specific mechanisms constrain the emergence of resistance. In this study, we first report ß-lactam tolerance due to the inactivation of the c-di-AMP phosphodiesterase GdpP. Mechanistically, tolerance depends on antagonistic regulation by the repressor BusR, which is activated by c-di-AMP and negatively regulates ß-lactam susceptibility through the BusAB osmolyte transporter and the AmaP/Asp23/GlsB cell envelope stress complex. The BusR transcriptional response is synergistic with the simultaneous allosteric inhibition of potassium and osmolyte transporters by c-di-AMP, which individually contribute to low-level ß-lactam tolerance. Genome-wide transposon mutagenesis confirms the role of GdpP and highlights functional interactions between a lysozyme-like hydrolase, the KhpAB RNA chaperone and the protein S immunomodulator in the response of GBS to ß-lactam. Overall, we demonstrate that c-di-AMP acts as a turgor pressure rheostat, coordinating an integrated response at the transcriptional and post-translational levels to cell wall weakening caused by ß-lactam activity, and reveal additional mechanisms that could foster resistance.
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Affiliation(s)
- Terry Brissac
- Department of Microbiology, Biology of Gram-positive Pathogens, Institut Pasteur, Université Paris Cité, 75015, Paris, France
| | - Cécile Guyonnet
- Université Paris Cité, Institut Cochin, Institut National de la Santé et de la Recherche Médicale U1016, Centre National de la Recherche Scientifique UMR8104, Team Bacteria and Perinatality, 75015, Paris, France
- Department of Bacteriology, French National Reference Center for Streptococci, Assistance Publique-Hôpitaux de Paris Hôpitaux Universitaires Paris Centre, Hôpital Cochin, 75005, Paris, France
- Fédération Hospitalo-Universitaire Fighting Prematurity, 75005, Paris, France
| | - Aymane Sadouni
- Department of Microbiology, Biology of Gram-positive Pathogens, Institut Pasteur, Université Paris Cité, 75015, Paris, France
| | - Ariadna Hernández-Montoya
- Department of Microbiology, Biology of Gram-positive Pathogens, Institut Pasteur, Université Paris Cité, 75015, Paris, France
| | - Elise Jacquemet
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, 75015 Paris, France
| | - Rachel Legendre
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, 75015 Paris, France
| | - Odile Sismeiro
- Department of Microbiology, Biology of Gram-positive Pathogens, Institut Pasteur, Université Paris Cité, 75015, Paris, France
| | - Patrick Trieu-Cuot
- Department of Microbiology, Biology of Gram-positive Pathogens, Institut Pasteur, Université Paris Cité, 75015, Paris, France
| | - Philippe Lanotte
- Université de Tours, INRAE, UMR 1282 ISP, 3700, Tours, France
- CHRU de Tours, Service de Bactériologie-Virologie, 37044, Tours, France
| | - Asmaa Tazi
- Université Paris Cité, Institut Cochin, Institut National de la Santé et de la Recherche Médicale U1016, Centre National de la Recherche Scientifique UMR8104, Team Bacteria and Perinatality, 75015, Paris, France
- Department of Bacteriology, French National Reference Center for Streptococci, Assistance Publique-Hôpitaux de Paris Hôpitaux Universitaires Paris Centre, Hôpital Cochin, 75005, Paris, France
- Fédération Hospitalo-Universitaire Fighting Prematurity, 75005, Paris, France
| | - Arnaud Firon
- Department of Microbiology, Biology of Gram-positive Pathogens, Institut Pasteur, Université Paris Cité, 75015, Paris, France
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3
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Bourqqia-Ramzi M, Mansilla-Guardiola J, Muñoz-Rodriguez D, Quarta E, Lombardo-Hernandez J, Murciano-Cespedosa A, Conejero-Meca FJ, Mateos González Á, Geuna S, Garcia-Esteban MT, Herrera-Rincon C. From the Microbiome to the Electrome: Implications for the Microbiota-Gut-Brain Axis. Int J Mol Sci 2024; 25:6233. [PMID: 38892419 PMCID: PMC11172653 DOI: 10.3390/ijms25116233] [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: 04/09/2024] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 06/21/2024] Open
Abstract
The gut microbiome plays a fundamental role in metabolism, as well as the immune and nervous systems. Microbial imbalance (dysbiosis) can contribute to subsequent physical and mental pathologies. As such, interest has been growing in the microbiota-gut-brain brain axis and the bioelectrical communication that could exist between bacterial and nervous cells. The aim of this study was to investigate the bioelectrical profile (electrome) of two bacterial species characteristic of the gut microbiome: a Proteobacteria Gram-negative bacillus Escherichia coli (E. coli), and a Firmicutes Gram-positive coccus Enterococcus faecalis (E. faecalis). We analyzed both bacterial strains to (i) validate the fluorescent probe bis-(1,3-dibutylbarbituric acid) trimethine oxonol, DiBAC4(3), as a reliable reporter of the changes in membrane potential (Vmem) for both bacteria; (ii) assess the evolution of the bioelectric profile throughout the growth of both strains; (iii) investigate the effects of two neural-type stimuli on Vmem changes: the excitatory neurotransmitter glutamate (Glu) and the inhibitory neurotransmitter γ-aminobutyric acid (GABA); (iv) examine the impact of the bioelectrical changes induced by neurotransmitters on bacterial growth, viability, and cultivability using absorbance, live/dead fluorescent probes, and viable counts, respectively. Our findings reveal distinct bioelectrical profiles characteristic of each bacterial species and growth phase. Importantly, neural-type stimuli induce Vmem changes without affecting bacterial growth, viability, or cultivability, suggesting a specific bioelectrical response in bacterial cells to neurotransmitter cues. These results contribute to understanding the bacterial response to external stimuli, with potential implications for modulating bacterial bioelectricity as a novel therapeutic target.
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Affiliation(s)
- Marwane Bourqqia-Ramzi
- Modeling, Data Analysis &Computational Tools for Biology Research Group, Biomathematics Unit, Department of Biodiversity, Ecology & Evolution, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain; (M.B.-R.); (J.M.-G.)
- Department of Neurosciences “Rita Levi Montalcini”, University of Turin, 10126 Turin, Italy
| | - Jesús Mansilla-Guardiola
- Modeling, Data Analysis &Computational Tools for Biology Research Group, Biomathematics Unit, Department of Biodiversity, Ecology & Evolution, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain; (M.B.-R.); (J.M.-G.)
- Unit of Microbiology, Department of Genetic, Physiology and Microbiology, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain
| | - David Muñoz-Rodriguez
- Modeling, Data Analysis &Computational Tools for Biology Research Group, Biomathematics Unit, Department of Biodiversity, Ecology & Evolution, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain; (M.B.-R.); (J.M.-G.)
| | - Elisa Quarta
- Modeling, Data Analysis &Computational Tools for Biology Research Group, Biomathematics Unit, Department of Biodiversity, Ecology & Evolution, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain; (M.B.-R.); (J.M.-G.)
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center “Guido Tarone”, University of Torino, 10126 Turin, Italy
| | - Juan Lombardo-Hernandez
- Modeling, Data Analysis &Computational Tools for Biology Research Group, Biomathematics Unit, Department of Biodiversity, Ecology & Evolution, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain; (M.B.-R.); (J.M.-G.)
| | - Antonio Murciano-Cespedosa
- Modeling, Data Analysis &Computational Tools for Biology Research Group, Biomathematics Unit, Department of Biodiversity, Ecology & Evolution, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain; (M.B.-R.); (J.M.-G.)
- Neuro-Computing and Neuro-Robotics Research Group, Neural Plasticity Research Group Instituto Investigación Sanitaria Hospital Clínico San Carlos (IdISSC), Complutense University of Madrid, 28040 Madrid, Spain
| | - Francisco José Conejero-Meca
- Modeling, Data Analysis &Computational Tools for Biology Research Group, Biomathematics Unit, Department of Biodiversity, Ecology & Evolution, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain; (M.B.-R.); (J.M.-G.)
| | - Álvaro Mateos González
- Modeling, Data Analysis &Computational Tools for Biology Research Group, Biomathematics Unit, Department of Biodiversity, Ecology & Evolution, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain; (M.B.-R.); (J.M.-G.)
- University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Stefano Geuna
- Department of Clinical and Biological Sciences, Cavalieri Ottolenghi Neuroscience Institute, University of Turin, Ospedale San Luigi, 10043 Turin, Italy
| | - María Teresa Garcia-Esteban
- Unit of Microbiology, Department of Genetic, Physiology and Microbiology, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain
| | - Celia Herrera-Rincon
- Modeling, Data Analysis &Computational Tools for Biology Research Group, Biomathematics Unit, Department of Biodiversity, Ecology & Evolution, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain; (M.B.-R.); (J.M.-G.)
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4
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Cylke A, Serbanescu D, Banerjee S. Energy allocation theory for bacterial growth control in and out of steady state. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.09.574890. [PMID: 38260684 PMCID: PMC10802433 DOI: 10.1101/2024.01.09.574890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Efficient allocation of energy resources to key physiological functions allows living organisms to grow and thrive in diverse environments and adapt to a wide range of perturbations. To quantitatively understand how unicellular organisms utilize their energy resources in response to changes in growth environment, we introduce a theory of dynamic energy allocation which describes cellular growth dynamics based on partitioning of metabolizable energy into key physiological functions: growth, division, cell shape regulation, energy storage and loss through dissipation. By optimizing the energy flux for growth, we develop the equations governing the time evolution of cell morphology and growth rate in diverse environments. The resulting model accurately captures experimentally observed dependencies of bacterial cell size on growth rate, superlinear scaling of metabolic rate with cell size, and predicts nutrient-dependent trade-offs between energy expended for growth, division, and shape maintenance. By calibrating model parameters with available experimental data for the model organism E. coli, our model is capable of describing bacterial growth control in dynamic conditions, particularly during nutrient shifts and osmotic shocks. The model captures these perturbations with minimal added complexity and our unified approach predicts the driving factors behind a wide range of observed morphological and growth phenomena.
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Affiliation(s)
- Arianna Cylke
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Diana Serbanescu
- Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
- Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK
| | - Shiladitya Banerjee
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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5
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Kitahara Y, van Teeffelen S. Bacterial growth - from physical principles to autolysins. Curr Opin Microbiol 2023; 74:102326. [PMID: 37279609 DOI: 10.1016/j.mib.2023.102326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 06/08/2023]
Abstract
For bacteria to increase in size, they need to enzymatically expand their cell envelopes, and more concretely their peptidoglycan cell wall. A major task of growth is to increase intracellular space for the accumulation of macromolecules, notably proteins, RNA, and DNA. Here, we review recent progress in our understanding of how cells coordinate envelope growth with biomass growth, focusing on elongation of rod-like bacteria. We first describe the recent discovery that surface area, but not cell volume, increases in proportion to mass growth. We then discuss how this relation could possibly be implemented mechanistically, reviewing the role of envelope insertion for envelope growth. Since cell-wall expansion requires the well-controlled activity of autolysins, we finally review recent progress in our understanding of autolysin regulation.
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Affiliation(s)
- Yuki Kitahara
- Département de Microbiologie, Infectiologie, et Immunologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Sven van Teeffelen
- Département de Microbiologie, Infectiologie, et Immunologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada.
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6
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Brauer AM, Shi H, Levin PA, Huang KC. Physiological and regulatory convergence between osmotic and nutrient stress responses in microbes. Curr Opin Cell Biol 2023; 81:102170. [PMID: 37119759 PMCID: PMC10493190 DOI: 10.1016/j.ceb.2023.102170] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 03/09/2023] [Accepted: 03/20/2023] [Indexed: 05/01/2023]
Abstract
Bacterial cells are regularly confronted with simultaneous changes in environmental nutrient supply and osmolarity. Despite the importance of osmolarity and osmoregulation in bacterial physiology, the relationship between the cellular response to osmotic perturbations and other stresses has remained largely unexplored. Bacteria cultured in hyperosmotic conditions and bacteria experiencing nutrient stress exhibit similar physiological changes, including metabolic shutdown, increased protein instability, dehydration, and condensation of chromosomal DNA. In this review, we highlight overlapping molecular players between osmotic and nutrient stresses. These connections between two seemingly disparate stress response pathways reinforce the importance of central carbon metabolism as a control point for diverse aspects of homeostatic regulation. We identify important open questions for future research, emphasizing the pressing need to develop and exploit new methods for probing how osmolarity affects phylogenetically diverse species.
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Affiliation(s)
- Adrienne M Brauer
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Handuo Shi
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Petra Anne Levin
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA.
| | - Kerwyn Casey Huang
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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7
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Han R, Feng XQ, Vollmer W, Stoodley P, Chen J. Deciphering the adaption of bacterial cell wall mechanical integrity and turgor to different chemical or mechanical environments. J Colloid Interface Sci 2023; 640:510-520. [PMID: 36878069 DOI: 10.1016/j.jcis.2023.02.100] [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: 12/28/2022] [Revised: 02/16/2023] [Accepted: 02/19/2023] [Indexed: 02/24/2023]
Abstract
Bacteria adapt the mechanical properties of their cell envelope, including cell wall stiffness, turgor, and cell wall tension and deformation, to grow and survive in harsh environments. However, it remains a technical challenge to simultaneously determine these mechanical properties at a single cell level. Here we combined theoretical modelling with an experimental approach to quantify the mechanical properties and turgor of Staphylococcus epidermidis. It was found that high osmolarity leads to a decrease in both cell wall stiffness and turgor. We also demonstrated that the turgor change is associated with a change in the viscosity of the bacterial cell. We predicted that the cell wall tension is much higher in deionized (DI) water and it decreases with an increase in osmolality. We also found that an external force increases the cell wall deformation to reinforce its adherence to a surface and this effect can be more significant in lower osmolarity. Overall, our work highlights how bacterial mechanics supports survival in harsh environments and uncovers the adaption of bacterial cell wall mechanical integrity and turgor to osmotic and mechanical challenges.
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Affiliation(s)
- Rui Han
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Xi-Qiao Feng
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4AX, UK
| | - Paul Stoodley
- Department of Microbial Infection and Immunity and the Department of Orthopaedics, The Ohio State University, Columbus, OH 43210, United States; National Centre for Advanced Tribology at Southampton (nCATS), National Biofilm Innovation Centre (NBIC), Mechanical Engineering, University of Southampton, Southampton S017 1BJ, UK
| | - Jinju Chen
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
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8
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Cesar S, Sun J, Huang KC. Cellular memory of rapid growth is sensitive to nutrient depletion during starvation. Front Microbiol 2022; 13:1016371. [DOI: 10.3389/fmicb.2022.1016371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 11/01/2022] [Indexed: 11/22/2022] Open
Abstract
Bacteria frequently encounter nutrient fluctuations in natural environments, yet we understand little about their ability to maintain physiological memory of previous food sources. Starvation is a particularly acute case, in which cells must balance adaptation to stresses with limited nutrient supply. Here, we show that Escherichia coli cells immediately accelerate and decelerate in growth upon transitions from spent to fresh media and vice versa, respectively, and memory of rapid growth can be maintained for many hours under constant flow of spent medium. However, after transient exposure of stationary-phase cells to fresh medium, subsequent aerobic incubation in increasingly spent medium led to lysis and limited growth when rejuvenated in fresh medium. Growth defects were avoided by incubation in anaerobic spent medium or water, suggesting that defects were caused by respiration during the process of nutrient depletion in spent medium. These findings highlight the importance of respiration for stationary phase survival and underscore the broad range of starvation outcomes depending on environmental history.
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9
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Kitahara Y, Oldewurtel ER, Wilson S, Sun Y, Altabe S, de Mendoza D, Garner EC, van Teeffelen S. The role of cell-envelope synthesis for envelope growth and cytoplasmic density in Bacillus subtilis. PNAS NEXUS 2022; 1:pgac134. [PMID: 36082236 PMCID: PMC9437589 DOI: 10.1093/pnasnexus/pgac134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 07/21/2022] [Indexed: 01/29/2023]
Abstract
All cells must increase their volumes in response to biomass growth to maintain intracellular mass density within physiologically permissive bounds. Here, we investigate the regulation of volume growth in the Gram-positive bacterium Bacillus subtilis. To increase volume, bacteria enzymatically expand their cell envelopes and insert new envelope material. First, we demonstrate that cell-volume growth is determined indirectly, by expanding their envelopes in proportion to mass growth, similarly to the Gram-negative Escherichia coli, despite their fundamentally different envelope structures. Next, we studied, which pathways might be responsible for robust surface-to-mass coupling: We found that both peptidoglycan synthesis and membrane synthesis are required for proper surface-to-mass coupling. However, surprisingly, neither pathway is solely rate-limiting, contrary to wide-spread belief, since envelope growth continues at a reduced rate upon complete inhibition of either process. To arrest cell-envelope growth completely, the simultaneous inhibition of both envelope-synthesis processes is required. Thus, we suggest that multiple envelope-synthesis pathways collectively confer an important aspect of volume regulation, the coordination between surface growth, and biomass growth.
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Affiliation(s)
- Yuki Kitahara
- Département de Microbiologie, Infectiologie, et Immunologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada,Université de Paris, Paris, France,Microbial Morphogenesis and Growth Lab, Institut Pasteur, Paris, France
| | - Enno R Oldewurtel
- Microbial Morphogenesis and Growth Lab, Institut Pasteur, Paris, France
| | - Sean Wilson
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, USA,Center for Systems Biology, Harvard University, Cambridge, MA, USA
| | - Yingjie Sun
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, USA,Center for Systems Biology, Harvard University, Cambridge, MA, USA
| | - Silvia Altabe
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Conicet- and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Diego de Mendoza
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Conicet- and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, USA,Center for Systems Biology, Harvard University, Cambridge, MA, USA
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10
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Abstract
Bacteria have evolved to develop multiple strategies for antibiotic resistance by effectively reducing intracellular antibiotic concentrations or antibiotic binding affinities, but the role of cell morphology in antibiotic resistance remains poorly understood. By analyzing cell morphological data for different bacterial species under antibiotic stress, we find that bacteria increase or decrease the cell surface-to-volume ratio depending on the antibiotic target. Using quantitative modeling, we show that by reducing the surface-to-volume ratio, bacteria can effectively reduce the intracellular antibiotic concentration by decreasing antibiotic influx. The model further predicts that bacteria can increase the surface-to-volume ratio to induce the dilution of membrane-targeting antibiotics, in agreement with experimental data. Using a whole-cell model for the regulation of cell shape and growth by antibiotics, we predict shape transformations that bacteria can utilize to increase their fitness in the presence of antibiotics. We conclude by discussing additional pathways for antibiotic resistance that may act in synergy with shape-induced resistance.
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11
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Sun J, Rutherford ST, Silhavy TJ, Huang KC. Physical properties of the bacterial outer membrane. Nat Rev Microbiol 2022; 20:236-248. [PMID: 34732874 PMCID: PMC8934262 DOI: 10.1038/s41579-021-00638-0] [Citation(s) in RCA: 93] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2021] [Indexed: 11/09/2022]
Abstract
It has long been appreciated that the Gram-negative outer membrane acts as a permeability barrier, but recent studies have uncovered a more expansive and versatile role for the outer membrane in cellular physiology and viability. Owing to recent developments in microfluidics and microscopy, the structural, rheological and mechanical properties of the outer membrane are becoming apparent across multiple scales. In this Review, we discuss experimental and computational studies that have revealed key molecular factors and interactions that give rise to the spatial organization, limited diffusivity and stress-bearing capacity of the outer membrane. These physical properties suggest broad connections between cellular structure and physiology, and we explore future prospects for further elucidation of the implications of outer membrane construction for cellular fitness and survival.
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Affiliation(s)
- Jiawei Sun
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Steven T. Rutherford
- Department of Infectious Diseases, Genentech Inc., South San Francisco, CA 94080, USA,To whom correspondence should be addressed: , ,
| | - Thomas J. Silhavy
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA,To whom correspondence should be addressed: , ,
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA, USA. .,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA. .,Chan Zuckerberg Biohub, San Francisco, CA, USA.
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12
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Alric B, Formosa-Dague C, Dague E, Holt LJ, Delarue M. Macromolecular crowding limits growth under pressure. NATURE PHYSICS 2022; 18:411-416. [PMID: 37152719 PMCID: PMC10162713 DOI: 10.1038/s41567-022-01506-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Cells that grow in confined spaces eventually build up mechanical compressive stress. This growth-induced pressure (GIP) decreases cell growth. GIP is important in a multitude of contexts from cancer, to microbial infections, to biofouling, yet our understanding of its origin and molecular consequences remains limited. Here, we combine microfluidic confinement of the yeast Saccharomyces cerevisiae, with rheological measurements using genetically encoded multimeric nanoparticles (GEMs) to reveal that growth-induced pressure is accompanied with an increase in a key cellular physical property: macromolecular crowding. We develop a fully calibrated model that predicts how increased macromolecular crowding hinders protein expression and thus diminishes cell growth. This model is sufficient to explain the coupling of growth rate to pressure without the need for specific molecular sensors or signaling cascades. As molecular crowding is similar across all domains of life, this could be a deeply conserved mechanism of biomechanical feedback that allows environmental sensing originating from the fundamental physical properties of cells.
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Affiliation(s)
- Baptiste Alric
- MILE team, CNRS, UPR8001, LAAS-CNRS, 7 Avenue du Colonel Roche, F-31400 Toulouse, France
| | | | - Etienne Dague
- ELIA team, CNRS, UPR8001, LAAS-CNRS, 7 Avenue du Colonel Roche, F-31400 Toulouse, France
| | - Liam J. Holt
- New York University Grossman School of Medicine, Institute for Systems Genetics, 435 E 30th Street, New York, NY, United States
- to whom correspondence should be addressed: ;
| | - Morgan Delarue
- MILE team, CNRS, UPR8001, LAAS-CNRS, 7 Avenue du Colonel Roche, F-31400 Toulouse, France
- to whom correspondence should be addressed: ;
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13
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Affiliation(s)
- Xu Han
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
| | - Christine K. Payne
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
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14
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Mandela E, Stubenrauch CJ, Ryoo D, Hwang H, Cohen EJ, Torres VVL, Deo P, Webb CT, Huang C, Schittenhelm RB, Beeby M, Gumbart JC, Lithgow T, Hay ID. Adaptation of the periplasm to maintain spatial constraints essential for cell envelope processes and cell viability. eLife 2022; 11:73516. [PMID: 35084330 PMCID: PMC8824477 DOI: 10.7554/elife.73516] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 01/21/2022] [Indexed: 11/17/2022] Open
Abstract
The cell envelope of Gram-negative bacteria consists of two membranes surrounding a periplasm and peptidoglycan layer. Molecular machines spanning the cell envelope depend on spatial constraints and load-bearing forces across the cell envelope and surface. The mechanisms dictating spatial constraints across the cell envelope remain incompletely defined. In Escherichia coli, the coiled-coil lipoprotein Lpp contributes the only covalent linkage between the outer membrane and the underlying peptidoglycan layer. Using proteomics, molecular dynamics, and a synthetic lethal screen, we show that lengthening Lpp to the upper limit does not change the spatial constraint but is accommodated by other factors which thereby become essential for viability. Our findings demonstrate E. coli expressing elongated Lpp does not simply enlarge the periplasm in response, but the bacteria accommodate by a combination of tilting Lpp and reducing the amount of the covalent bridge. By genetic screening, we identified all of the genes in E. coli that become essential in order to enact this adaptation, and by quantitative proteomics discovered that very few proteins need to be up- or down-regulated in steady-state levels in order to accommodate the longer Lpp. We observed increased levels of factors determining cell stiffness, a decrease in membrane integrity, an increased membrane vesiculation and a dependance on otherwise non-essential tethers to maintain lipid transport and peptidoglycan biosynthesis. Further this has implications for understanding how spatial constraint across the envelope controls processes such as flagellum-driven motility, cellular signaling, and protein translocation
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Affiliation(s)
- Eric Mandela
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | | | - David Ryoo
- Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, United States
| | - Hyea Hwang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States
| | - Eli J Cohen
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | | | - Pankaj Deo
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Chaille T Webb
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Cheng Huang
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Ralf B Schittenhelm
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Morgan Beeby
- Department of Life Sciencesa, Imperial College London, London, United Kingdom
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, United States
| | - Trevor Lithgow
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Iain D Hay
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
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15
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Gomez D, Peña Ccoa WJ, Singh Y, Rojas E, Hocky GM. Molecular Paradigms for Biological Mechanosensing. J Phys Chem B 2021; 125:12115-12124. [PMID: 34709040 DOI: 10.1021/acs.jpcb.1c06330] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many proteins in living cells are subject to mechanical forces, which can be generated internally by molecular machines, or externally, e.g., by pressure gradients. In general, these forces fall in the piconewton range, which is similar in magnitude to forces experienced by a molecule due to thermal fluctuations. While we would naively expect such moderate forces to produce only minimal changes, a wide variety of "mechanosensing" proteins have evolved with functions that are responsive to forces in this regime. The goal of this article is to provide a physical chemistry perspective on protein-based molecular mechanosensing paradigms used in living systems, and how these paradigms can be explored using novel computational methods.
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Affiliation(s)
- David Gomez
- Department of Biology, New York University, New York, New York 10003, United States.,Department of Chemistry, New York University, New York, New York 10003, United States
| | - Willmor J Peña Ccoa
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Yuvraj Singh
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Enrique Rojas
- Department of Biology, New York University, New York, New York 10003, United States
| | - Glen M Hocky
- Department of Chemistry, New York University, New York, New York 10003, United States
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16
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Sun J, Shi H, Huang KC. Hyperosmotic Shock Transiently Accelerates Constriction Rate in Escherichia coli. Front Microbiol 2021; 12:718600. [PMID: 34489908 PMCID: PMC8418109 DOI: 10.3389/fmicb.2021.718600] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 07/26/2021] [Indexed: 11/13/2022] Open
Abstract
Bacterial cells in their natural environments encounter rapid and large changes in external osmolality. For instance, enteric bacteria such as Escherichia coli experience a rapid decrease when they exit from host intestines. Changes in osmolality alter the mechanical load on the cell envelope, and previous studies have shown that large osmotic shocks can slow down bacterial growth and impact cytoplasmic diffusion. However, it remains unclear how cells maintain envelope integrity and regulate envelope synthesis in response to osmotic shocks. In this study, we developed an agarose pad-based protocol to assay envelope stiffness by measuring population-averaged cell length before and after a hyperosmotic shock. Pad-based measurements exhibited an apparently larger length change compared with single-cell dynamics in a microfluidic device, which we found was quantitatively explained by a transient increase in division rate after the shock. Inhibiting cell division led to consistent measurements between agarose pad-based and microfluidic measurements. Directly after hyperosmotic shock, FtsZ concentration and Z-ring intensity increased, and the rate of septum constriction increased. These findings establish an agarose pad-based protocol for quantifying cell envelope stiffness, and demonstrate that mechanical perturbations can have profound effects on bacterial physiology.
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Affiliation(s)
- Jiawei Sun
- Department of Bioengineering, Stanford University, Stanford, CA, United States
| | - Handuo Shi
- Department of Bioengineering, Stanford University, Stanford, CA, United States.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, United States
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA, United States.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, United States.,Chan Zuckerberg Biohub, San Francisco, CA, United States
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17
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Robust surface-to-mass coupling and turgor-dependent cell width determine bacterial dry-mass density. Proc Natl Acad Sci U S A 2021; 118:2021416118. [PMID: 34341116 PMCID: PMC8364103 DOI: 10.1073/pnas.2021416118] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Intracellular biomass density is an important variable for cellular physiology. It defines the crowded state of the cytoplasm and thus influences macromolecular interactions and transport. To control density during growth, bacteria must expand their cell volumes in synchrony with biomass. The regulation of volume growth and biomass density remain fundamentally not understood—in bacteria or any other organism. Using advanced microscopy, we demonstrate that cells control dry-mass density indirectly through two independent processes. First, cells expand surface area, rather than volume, in proportion with biomass growth. Second, cell width is controlled independently, with an important influence of turgor pressure. Our findings overturn a long-standing paradigm of mass-density constancy in bacteria and reveal fundamental determinants of dry-mass density and shape. During growth, cells must expand their cell volumes in coordination with biomass to control the level of cytoplasmic macromolecular crowding. Dry-mass density, the average ratio of dry mass to volume, is roughly constant between different nutrient conditions in bacteria, but it remains unknown whether cells maintain dry-mass density constant at the single-cell level and during nonsteady conditions. Furthermore, the regulation of dry-mass density is fundamentally not understood in any organism. Using quantitative phase microscopy and an advanced image-analysis pipeline, we measured absolute single-cell mass and shape of the model organisms Escherichia coli and Caulobacter crescentus with improved precision and accuracy. We found that cells control dry-mass density indirectly by expanding their surface, rather than volume, in direct proportion to biomass growth—according to an empirical surface growth law. At the same time, cell width is controlled independently. Therefore, cellular dry-mass density varies systematically with cell shape, both during the cell cycle or after nutrient shifts, while the surface-to-mass ratio remains nearly constant on the generation time scale. Transient deviations from constancy during nutrient shifts can be reconciled with turgor-pressure variations and the resulting elastic changes in surface area. Finally, we find that plastic changes of cell width after nutrient shifts are likely driven by turgor variations, demonstrating an important regulatory role of mechanical forces for width regulation. In conclusion, turgor-dependent cell width and a slowly varying surface-to-mass coupling constant are the independent variables that determine dry-mass density.
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18
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Abstract
Environmental fluctuations are a common challenge for single-celled organisms; enteric bacteria such as Escherichia coli experience dramatic changes in nutrient availability, pH, and temperature during their journey into and out of the host. While the effects of altered nutrient availability on gene expression and protein synthesis are well known, their impacts on cytoplasmic dynamics and cell morphology have been largely overlooked. Here, we discover that depletion of utilizable nutrients results in shrinkage of E. coli's inner membrane from the cell wall. Shrinkage was accompanied by an ∼17% reduction in cytoplasmic volume and a concurrent increase in periplasmic volume. Inner membrane retraction after sudden starvation occurred almost exclusively at the new cell pole. This phenomenon was distinct from turgor-mediated plasmolysis and independent of new transcription, translation, or canonical starvation-sensing pathways. Cytoplasmic dry-mass density increased during shrinkage, suggesting that it is driven primarily by loss of water. Shrinkage was reversible: upon a shift to nutrient-rich medium, expansion started almost immediately at a rate dependent on carbon source quality. A robust entry into and recovery from shrinkage required the Tol-Pal system, highlighting the importance of envelope coupling during shrinkage and recovery. Klebsiella pneumoniae also exhibited shrinkage when shifted to carbon-free conditions, suggesting a conserved phenomenon. These findings demonstrate that even when Gram-negative bacterial growth is arrested, cell morphology and physiology are still dynamic.
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19
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Han X, Foster BR, Payne CK. Electrical Control of Escherichia coli Growth Measured with Simultaneous Modulation and Imaging. Bioelectricity 2020; 2:221-228. [PMID: 34476354 PMCID: PMC8370336 DOI: 10.1089/bioe.2020.0002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background: The use of electricity to mediate bacterial growth is unique in providing spatial control, but requires a more detailed understanding. Methods: We use two gold wires on a glass coverslip with an overlayer of agar to image Escherichia coli cells with brightfield and fluorescence microscopy while simultaneously applying a voltage. Cells outside of the wires provide a control population to measure cell growth as a function of voltage, rather than any difference in culture conditions or growth phase. Results: An applied voltage suppresses the fraction of E. coli undergoing elongation and division with recovery to control values when the voltage is removed. Depolarization is observed over the same voltage range suggesting a membrane potential-mediated response. Conclusions: Our experiments identify and use subcytotoxic voltages to measure differences in the fraction of E. coli cells elongating and dividing as a function of applied voltage. It is hoped that this research will inform the developing field of bacterial electrophysiology.
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Affiliation(s)
- Xu Han
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
| | - Bradley R. Foster
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
| | - Christine K. Payne
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
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20
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Bocchero U, Falleroni F, Mortal S, Li Y, Cojoc D, Lamb T, Torre V. Mechanosensitivity is an essential component of phototransduction in vertebrate rods. PLoS Biol 2020; 18:e3000750. [PMID: 32667916 PMCID: PMC7384764 DOI: 10.1371/journal.pbio.3000750] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 07/27/2020] [Accepted: 06/26/2020] [Indexed: 12/01/2022] Open
Abstract
Photoreceptors are specialized cells devoted to the transduction of the incoming visual signals. Rods are able also to shed from their tip old disks and to synthesize at the base of the outer segment (OS) new disks. By combining electrophysiology, optical tweezers (OTs), and biochemistry, we investigate mechanosensitivity in the rods of Xenopus laevis, and we show that 1) mechanosensitive channels (MSCs), transient receptor potential canonical 1 (TRPC1), and Piezo1 are present in rod inner segments (ISs); 2) mechanical stimulation—of the order of 10 pN—applied briefly to either the OS or IS evokes calcium transients; 3) inhibition of MSCs decreases the duration of photoresponses to bright flashes; 4) bright flashes of light induce a rapid shortening of the OS; and 5) the genes encoding the TRPC family have an ancient association with the genes encoding families of protein involved in phototransduction. These results suggest that MSCs play an integral role in rods’ phototransduction. It is widely thought that sensory neurons are specialized to transduce just a single sensory modality. A combination of electrophysiology, optical tweezers, and histochemistry reveals that rod photoreceptors not only express mechanosensitive channels but display mechanosensitivity, which is crucial for phototransduction.
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Affiliation(s)
- Ulisse Bocchero
- Neurobiology Department, International School for Advanced Studies, Trieste, Italy
| | - Fabio Falleroni
- Neurobiology Department, International School for Advanced Studies, Trieste, Italy
| | - Simone Mortal
- Neurobiology Department, International School for Advanced Studies, Trieste, Italy
| | - Yunzhen Li
- Neurobiology Department, International School for Advanced Studies, Trieste, Italy
| | - Dan Cojoc
- Institute of Materials, National Research Council of Italy (CNR), Trieste, Italy
| | - Trevor Lamb
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Vincent Torre
- Neurobiology Department, International School for Advanced Studies, Trieste, Italy
- Cixi Institute of Biomedical Engineering, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Zhejiang, China
- Center of Systems Medicine, Chinese Academy of Medical Sciences, Suzhou Institute of Systems Medicine, Suzhou Industrial Park, Suzhou, China
- * E-mail:
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21
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Romano OM, Cosentino Lagomarsino M. Single rod-shaped cell fluctuations from stochastic surface and volume growth rates. Phys Rev E 2020; 101:042403. [PMID: 32422852 DOI: 10.1103/physreve.101.042403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/10/2020] [Indexed: 11/07/2022]
Abstract
Growing rod-shaped bacterial cells need to modulate the production rates of different surface and bulk components. Population data show that the balance between these rates is central for cell physiology and affects cell shape, but we still know little about these processes in single cells. We study a minimal stochastic model where single cells grow by two fluctuating volume-specific surface and volume growth rates, solving for the steady-state distributions and the correlation functions of the main geometric features. Our predictions allow us to address the detectability of different scenarios for the intrinsic coupling between the allocation of resources to surface and bulk growth.
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Affiliation(s)
- Orso Maria Romano
- IFOM, The FIRC Institute of Molecular Oncology, via Adamello 16, 20139, Milan, Italy
| | - Marco Cosentino Lagomarsino
- IFOM, The FIRC Institute of Molecular Oncology, via Adamello 16, 20139, Milan, Italy.,Dipartimento di Fisica, Università degli Studi di Milano, and INFN, via Celoria 16, Milan, Italy
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22
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Arjes HA, Vo L, Dunn CM, Willis L, DeRosa CA, Fraser CL, Kearns DB, Huang KC. Biosurfactant-Mediated Membrane Depolarization Maintains Viability during Oxygen Depletion in Bacillus subtilis. Curr Biol 2020; 30:1011-1022.e6. [PMID: 32059765 PMCID: PMC7153240 DOI: 10.1016/j.cub.2020.01.073] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 12/09/2019] [Accepted: 01/23/2020] [Indexed: 12/26/2022]
Abstract
The presence or absence of oxygen in the environment is a strong effector of cellular metabolism and physiology. Like many eukaryotes and some bacteria, Bacillus subtilis primarily utilizes oxygen during respiration to generate ATP. Despite the importance of oxygen for B. subtilis survival, we know little about how populations adapt to shifts in oxygen availability. Here, we find that when oxygen was depleted from stationary phase B. subtilis cultures, ∼90% of cells died while the remaining cells maintained colony-forming ability. We discover that production of the antimicrobial surfactin confers two oxygen-related fitness benefits: it increases aerobic growth yield by increasing oxygen diffusion, and it maintains viability during oxygen depletion by depolarizing the membrane. Strains unable to produce surfactin exhibited an ∼50-fold reduction in viability after oxygen depletion. Surfactin treatment of these cells led to membrane depolarization and reduced ATP production. Chemical and genetic perturbations that alter oxygen consumption or redox state support a model in which surfactin-mediated membrane depolarization maintains viability through slower oxygen consumption and/or a shift to a more reduced metabolic profile. These findings highlight the importance of membrane potential in regulating cell physiology and growth, and demonstrate that antimicrobials that depolarize cell membranes can benefit cells when the terminal electron acceptor in respiration is limiting. This foundational knowledge has deep implications for environmental microbiology, clinical anti-bacterial therapy, and industrial biotechnology.
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Affiliation(s)
- Heidi A Arjes
- Department of Bioengineering, Stanford University School of Medicine, 443 via Ortega, Stanford, CA 94305, USA
| | - Lam Vo
- Department of Bioengineering, Stanford University School of Medicine, 443 via Ortega, Stanford, CA 94305, USA
| | - Caroline M Dunn
- Department of Biology, 1001 E 3rd Street, Indiana University, Bloomington, IN 47405, USA
| | - Lisa Willis
- Department of Bioengineering, Stanford University School of Medicine, 443 via Ortega, Stanford, CA 94305, USA
| | - Christopher A DeRosa
- Department of Chemistry, McCormick Road, University of Virginia, Charlottesville, VA 22904, USA
| | - Cassandra L Fraser
- Department of Chemistry, McCormick Road, University of Virginia, Charlottesville, VA 22904, USA
| | - Daniel B Kearns
- Department of Biology, 1001 E 3rd Street, Indiana University, Bloomington, IN 47405, USA.
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University School of Medicine, 443 via Ortega, Stanford, CA 94305, USA; Department of Microbiology & Immunology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, 499 Illinois Street, San Francisco, CA 94158, USA.
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23
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Rojas ER. The Mechanical Properties of Bacteria and Why they Matter. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1267:1-14. [PMID: 32894474 DOI: 10.1007/978-3-030-46886-6_1] [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: 01/01/2023]
Abstract
I review recent techniques to measure the mechanical properties of bacterial cells and their subcellular components, and then discuss what these techniques have revealed about the constitutive mechanical properties of whole bacterial cells and subcellular material, as well as the molecular basis for these properties.
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Affiliation(s)
- Enrique R Rojas
- Department of Biology, New York University, New York, NY, USA.
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24
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Bacillus subtilis cell diameter is determined by the opposing actions of two distinct cell wall synthetic systems. Nat Microbiol 2019; 4:1294-1305. [PMID: 31086310 PMCID: PMC6656618 DOI: 10.1038/s41564-019-0439-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 03/28/2019] [Indexed: 11/08/2022]
Abstract
Rod-shaped bacteria grow by adding material into their cell wall via the action of two spatially distinct enzymatic systems: the Rod complex moves around the cell circumference, whereas class A penicillin-binding proteins (aPBPs) do not. To understand how the combined action of these two systems defines bacterial dimensions, we examined how each affects the growth and width of Bacillus subtilis as well as the mechanical anisotropy and orientation of material within their sacculi. Rod width is not determined by MreB, rather it depends on the balance between the systems: the Rod complex reduces diameter, whereas aPBPs increase it. Increased Rod-complex activity correlates with an increased density of directional MreB filaments and a greater fraction of directional PBP2a enzymes. This increased circumferential synthesis increases the relative quantity of oriented material within the sacculi, making them more resistant to stretching across their width, thereby reinforcing rod shape. Together, these experiments explain how the combined action of the two main cell wall synthetic systems builds and maintains rods of different widths. Escherichia coli Rod mutants also show the same correlation between width and directional MreB filament density, suggesting this model may be generalizable to bacteria that elongate via the Rod complex.
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25
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Shi H, Bratton BP, Gitai Z, Huang KC. How to Build a Bacterial Cell: MreB as the Foreman of E. coli Construction. Cell 2019. [PMID: 29522748 DOI: 10.1016/j.cell.2018.02.050] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cell shape matters across the kingdoms of life, and cells have the remarkable capacity to define and maintain specific shapes and sizes. But how are the shapes of micron-sized cells determined from the coordinated activities of nanometer-sized proteins? Here, we review general principles that have surfaced through the study of rod-shaped bacterial growth. Imaging approaches have revealed that polymers of the actin homolog MreB play a central role. MreB both senses and changes cell shape, thereby generating a self-organizing feedback system for shape maintenance. At the molecular level, structural and computational studies indicate that MreB filaments exhibit tunable mechanical properties that explain their preference for certain geometries and orientations along the cylindrical cell body. We illustrate the regulatory landscape of rod-shape formation and the connectivity between cell shape, cell growth, and other aspects of cell physiology. These discoveries provide a framework for future investigations into the architecture and construction of microbes.
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Affiliation(s)
- Handuo Shi
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Benjamin P Bratton
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Zemer Gitai
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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26
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Harris LK, Theriot JA. Surface Area to Volume Ratio: A Natural Variable for Bacterial Morphogenesis. Trends Microbiol 2018; 26:815-832. [PMID: 29843923 DOI: 10.1016/j.tim.2018.04.008] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 04/23/2018] [Accepted: 04/27/2018] [Indexed: 11/16/2022]
Abstract
An immediately observable feature of bacteria is that cell size and shape are remarkably constant and characteristic for a given species in a particular condition, but vary quantitatively with physiological parameters such as growth rate, indicating both genetic and environmental regulation. However, despite decades of research, the molecular mechanisms underlying bacterial morphogenesis have remained incompletely characterized. We recently demonstrated that a wide range of bacterial species exhibit a robust surface area to volume ratio (SA/V) homeostasis. Because cell size, shape, and SA/V are mathematically interconnected, if SA/V is indeed the natural variable that cells actively monitor, this finding has critical implications for our understanding of bacterial morphogenesis, placing fundamental constraints on the sizes and shapes that cells can adopt. In this Opinion article we discuss the broad implications that this novel perspective has for the field of bacterial growth and morphogenesis.
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Affiliation(s)
- Leigh K Harris
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Julie A Theriot
- Department of Biochemistry, Department of Microbiology & Immunology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
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27
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Julien JD, Boudaoud A. Elongation and shape changes in organisms with cell walls: A dialogue between experiments and models. ACTA ACUST UNITED AC 2018; 1:34-42. [PMID: 32743126 PMCID: PMC7388974 DOI: 10.1016/j.tcsw.2018.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/06/2018] [Accepted: 04/08/2018] [Indexed: 11/28/2022]
Abstract
The generation of anisotropic shapes occurs during morphogenesis of almost all organisms. With the recent renewal of the interest in mechanical aspects of morphogenesis, it has become clear that mechanics contributes to anisotropic forms in a subtle interaction with various molecular actors. Here, we consider plants, fungi, oomycetes, and bacteria, and we review the mechanisms by which elongated shapes are generated and maintained. We focus on theoretical models of the interplay between growth and mechanics, in relation with experimental data, and discuss how models may help us improve our understanding of the underlying biological mechanisms.
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Affiliation(s)
- Jean-Daniel Julien
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, 46 allée d'Italie, 69364 Lyon Cedex 07, France.,Laboratoire de Physique, Univ. Lyon, ENS de Lyon, UCB Lyon 1, CNRS, 46 allée d'Italie, 69364 Lyon Cedex 07, France
| | - Arezki Boudaoud
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, 46 allée d'Italie, 69364 Lyon Cedex 07, France
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28
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Davì V, Tanimoto H, Ershov D, Haupt A, De Belly H, Le Borgne R, Couturier E, Boudaoud A, Minc N. Mechanosensation Dynamically Coordinates Polar Growth and Cell Wall Assembly to Promote Cell Survival. Dev Cell 2018; 45:170-182.e7. [DOI: 10.1016/j.devcel.2018.03.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 02/05/2018] [Accepted: 03/26/2018] [Indexed: 02/03/2023]
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29
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Puffal J, García-Heredia A, Rahlwes KC, Siegrist MS, Morita YS. Spatial control of cell envelope biosynthesis in mycobacteria. Pathog Dis 2018; 76:4953754. [DOI: 10.1093/femspd/fty027] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/25/2018] [Indexed: 11/12/2022] Open
Affiliation(s)
- Julia Puffal
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Alam García-Heredia
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Kathryn C Rahlwes
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - M Sloan Siegrist
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
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30
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van Teeffelen S, Renner LD. Recent advances in understanding how rod-like bacteria stably maintain their cell shapes. F1000Res 2018; 7:241. [PMID: 29560261 PMCID: PMC5832919 DOI: 10.12688/f1000research.12663.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/22/2018] [Indexed: 01/14/2023] Open
Abstract
Cell shape and cell volume are important for many bacterial functions. In recent years, we have seen a range of experimental and theoretical work that led to a better understanding of the determinants of cell shape and size. The roles of different molecular machineries for cell-wall expansion have been detailed and partially redefined, mechanical forces have been shown to influence cell shape, and new connections between metabolism and cell shape have been proposed. Yet the fundamental determinants of the different cellular dimensions remain to be identified. Here, we highlight some of the recent developments and focus on the determinants of rod-like cell shape and size in the well-studied model organisms
Escherichia coli and
Bacillus subtilis.
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Affiliation(s)
- Sven van Teeffelen
- Department of Microbiology, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Lars D Renner
- Leibniz Institute of Polymer Research and the Max Bergmann Center of Biomaterials, 01069 Dresden, Germany
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Abstract
The cellular adjustment of Bacteria and Archaea to high-salinity habitats is well studied and has generally been classified into one of two strategies. These are to accumulate high levels either of ions (the “salt-in” strategy) or of physiologically compliant organic osmolytes, the compatible solutes (the “salt-out” strategy). Halophilic protists are ecophysiological important inhabitants of salt-stressed ecosystems because they are not only very abundant but also represent the majority of eukaryotic lineages in nature. However, their cellular osmostress responses have been largely neglected. Recent reports have now shed new light on this issue using the geographically widely distributed halophilic heterotrophic protists Halocafeteria seosinensis, Pharyngomonas kirbyi, and Schmidingerothrix salinarum as model systems. Different approaches led to the joint conclusion that these unicellular Eukarya use the salt-out strategy to cope successfully with the persistent high salinity in their habitat. They accumulate various compatible solutes, e.g., glycine betaine, myo-inositol, and ectoines. The finding of intron-containing biosynthetic genes for ectoine and hydroxyectoine, their salt stress–responsive transcription in H. seosinensis, and the production of ectoine and its import by S. salinarum come as a considerable surprise because ectoines have thus far been considered exclusive prokaryotic compatible solutes. Phylogenetic considerations of the ectoine/hydroxyectoine biosynthetic genes of H. seosinensis suggest that they have been acquired via lateral gene transfer by these bacterivorous Eukarya from ectoine/hydroxyectoine-producing food bacteria that populate the same habitat.
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Affiliation(s)
- Laura Czech
- Department of Biology, Laboratory for Molecular Microbiology, Philipps-University Marburg, Marburg, Germany
| | - Erhard Bremer
- Department of Biology, Laboratory for Molecular Microbiology, Philipps-University Marburg, Marburg, Germany
- LOEWE-Center for Synthetic Microbiology, Philipps-University Marburg, Marburg, Germany
- * E-mail:
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32
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Rojas ER, Huang KC. Regulation of microbial growth by turgor pressure. Curr Opin Microbiol 2017; 42:62-70. [PMID: 29125939 DOI: 10.1016/j.mib.2017.10.015] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 10/19/2017] [Accepted: 10/22/2017] [Indexed: 12/24/2022]
Abstract
Rapid changes in environmental osmolarity are a natural aspect of microbial lifestyles. The change in turgor pressure resulting from an osmotic shock alters the mechanical forces within the cell envelope, and can impact cell growth across a range of timescales, through a variety of mechanical mechanisms. Here, we first summarize measurements of turgor pressure in various organisms. We then review how the combination of microfluidic flow cells and quantitative image analysis has driven discovery of the diverse ways in which turgor pressure mechanically regulates bacterial growth, independent of the effect of cytoplasmic crowding. In Gram-positive, rod-shaped bacteria, reductions in turgor pressure cause decreased growth rate. Moreover, a hypoosmotic shock, which increases turgor pressure and membrane tension, leads to transient inhibition of cell-wall growth via electrical depolarization. By contrast, Gram-negative Escherichia coli is remarkably insensitive to changes in turgor. We discuss the extent to which turgor pressure impacts processes such as cell division that alter cell shape, in particular that turgor facilitates millisecond-scale daughter-cell separation in many Actinobacteria and eukaryotic fission yeast. This diverse set of responses showcases the potential for using osmotic shocks to interrogate how mechanical perturbations affect cellular processes.
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Affiliation(s)
- Enrique R Rojas
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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