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Sawers RG. Perspective elucidating the physiology of a microbial cell: Neidhardt's Holy Grail. Mol Microbiol 2023; 120:54-59. [PMID: 36855806 DOI: 10.1111/mmi.15051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/24/2023] [Accepted: 02/26/2023] [Indexed: 03/02/2023]
Abstract
A living microbial cell represents a system of high complexity, integration, and extreme order. All processes within that cell interconvert free energy through a multitude of interconnected metabolic reactions that help to maintain the cell in a state of low entropy, which is a characteristic of all living systems. The study of macromolecular interactions outside this cellular environment yields valuable information about the molecular function of macromolecules but represents a system in comparative disorder. Consequently, care must always be taken in interpreting the information gleaned from such studies and must be compared with how the same macromolecules function in vivo, otherwise, discrepancies can arise. The importance of combining reductionist approaches with the study of whole-cell microbial physiology is discussed regarding the long-term aim of understanding how a cell functions in its entirety. This can only be achieved by the continued development of high-resolution structural and multi-omic technologies. It is only by studying the whole cell that we can ever hope to understand how living systems function.
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Affiliation(s)
- R Gary Sawers
- Institute of Microbiology, Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany
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2
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Yuan L, Straub H, Shishaeva L, Ren Q. Microfluidics for Biofilm Studies. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2023; 16:139-159. [PMID: 37314876 DOI: 10.1146/annurev-anchem-091522-103827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Biofilms are multicellular communities held together by a self-produced extracellular matrix and exhibit a set of properties that distinguish them from free-living bacteria. Biofilms are exposed to a variety of mechanical and chemical cues resulting from fluid motion and mass transport. Microfluidics provides the precise control of hydrodynamic and physicochemical microenvironments to study biofilms in general. In this review, we summarize the recent progress made in microfluidics-based biofilm research, including understanding the mechanism of bacterial adhesion and biofilm development, assessment of antifouling and antimicrobial properties, development of advanced in vitro infection models, and advancement in methods to characterize biofilms. Finally, we provide a perspective on the future direction of microfluidics-assisted biofilm research.
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Affiliation(s)
- Lu Yuan
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, China;
| | - Hervé Straub
- Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland;
| | - Liubov Shishaeva
- Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland;
| | - Qun Ren
- Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland;
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3
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Oliveira Paiva AM, Friggen AH, Douwes R, Wittekoek B, Smits WK. Practical observations on the use of fluorescent reporter systems in Clostridioides difficile. Antonie van Leeuwenhoek 2022; 115:297-323. [PMID: 35039954 DOI: 10.1007/s10482-021-01691-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 11/19/2021] [Indexed: 12/18/2022]
Abstract
Fluorescence microscopy is a valuable tool to study a broad variety of bacterial cell components and dynamics thereof. For Clostridioides difficile, the fluorescent proteins CFPopt, mCherryOpt and phiLOV2.1, and the self-labelling tags SNAPCd and HaloTag, hereafter collectively referred as fluorescent systems, have been described to explore different cellular pathways. In this study, we sought to characterize previously used fluorescent systems in C. difficile cells. We performed single cell analyses using fluorescence microscopy of exponentially growing C. difficile cells harbouring different fluorescent systems, either expressing these separately in the cytosol or fused to the C-terminus of HupA, under defined conditions. We show that the intrinsic fluorescence of C. difficile cells increases during growth, independent of sigB or spo0A. However, when C. difficile cells are exposed to environmental oxygen autofluorescence is enhanced. Cytosolic overexpression of the different fluorescent systems alone, using the same expression signals, showed heterogeneous expression of the fluorescent systems. High levels of mCherryOpt were toxic for C. difficile cells limiting the applicability of this fluorophore as a transcriptional reporter. When fused to HupA, a C. difficile histone-like protein, the fluorescent systems behaved similarly and did not affect the HupA overproduction phenotype. The present study compares several commonly used fluorescent systems for application as transcriptional or translational reporters in microscopy and summarizes the limitations and key challenges for live-cell imaging of C. difficile. Due to independence of molecular oxygen and fluorescent signal, SNAPCd appears the most suitable candidate for live-cell imaging in C. difficile to date.
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Affiliation(s)
- Ana M Oliveira Paiva
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands.,Center for Microbial Cell Biology, Leiden, The Netherlands.,Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, 91198, Gif-sur-Yvette, France
| | - Annemieke H Friggen
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands.,Center for Microbial Cell Biology, Leiden, The Netherlands
| | - Roxanne Douwes
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| | - Bert Wittekoek
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| | - Wiep Klaas Smits
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands. .,Center for Microbial Cell Biology, Leiden, The Netherlands.
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4
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Computerized fluorescence microscopy of microbial cells. World J Microbiol Biotechnol 2021; 37:189. [PMID: 34617135 DOI: 10.1007/s11274-021-03159-3] [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: 07/27/2021] [Accepted: 09/30/2021] [Indexed: 10/20/2022]
Abstract
The upgrading of fluorescence microscopy by the introduction of computer technologies has led to the creation of a new methodology, computerized fluorescence microscopy (CFM). CFM improves subjective visualization and combines it with objective quantitative analysis of the microscopic data. CFM has opened up two fundamentally new opportunities for studying microorganisms. The first is the quantitative measurement of the fluorescence parameters of the targeted fluorophores in association with certain structures of individual cells. The second is the expansion of the boundaries of visualization/resolution of intracellular components beyond the "diffraction limit" of light microscopy into the nanometer range. This enables to obtain unique information about the localization and dynamics of intracellular processes at the molecular level. The purpose of this review is to demonstrate the potential of CFM in the study of fundamental aspects of the structural and functional organization of microbial cells. The basics of computer processing and analysis of digital images are briefly described. The fluorescent molecules used in CFM with an emphasis on fluorescent proteins are characterized. The main methods of super-resolution microscopy (nanoscopy) are presented. The capabilities of various CFM methods for exploring microbial cells at the subcellular level are illustrated by the examples of various studies on yeast and bacteria.
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5
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Unappreciated Roles for K+ Channels in Bacterial Physiology. Trends Microbiol 2021; 29:942-950. [DOI: 10.1016/j.tim.2020.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/07/2020] [Accepted: 11/09/2020] [Indexed: 01/03/2023]
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Turkowyd B, Schreiber S, Wörtz J, Segal ES, Mevarech M, Duggin IG, Marchfelder A, Endesfelder U. Establishing Live-Cell Single-Molecule Localization Microscopy Imaging and Single-Particle Tracking in the Archaeon Haloferax volcanii. Front Microbiol 2020; 11:583010. [PMID: 33329447 PMCID: PMC7714787 DOI: 10.3389/fmicb.2020.583010] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 10/16/2020] [Indexed: 01/30/2023] Open
Abstract
In recent years, fluorescence microscopy techniques for the localization and tracking of single molecules in living cells have become well-established and are indispensable tools for the investigation of cellular biology and in vivo biochemistry of many bacterial and eukaryotic organisms. Nevertheless, these techniques are still not established for imaging archaea. Their establishment as a standard tool for the study of archaea will be a decisive milestone for the exploration of this branch of life and its unique biology. Here, we have developed a reliable protocol for the study of the archaeon Haloferax volcanii. We have generated an autofluorescence-free H. volcanii strain, evaluated several fluorescent proteins for their suitability to serve as single-molecule fluorescence markers and codon-optimized them to work under optimal H. volcanii cultivation conditions. We found that two of them, Dendra2Hfx and PAmCherry1Hfx, provide state-of-the-art single-molecule imaging. Our strategy is quantitative and allows dual-color imaging of two targets in the same field of view (FOV) as well as DNA co-staining. We present the first single-molecule localization microscopy (SMLM) images of the subcellular organization and dynamics of two crucial intracellular proteins in living H. volcanii cells, FtsZ1, which shows complex structures in the cell division ring, and RNA polymerase, which localizes around the periphery of the cellular DNA. This work should provide incentive to develop SMLM strategies for other archaeal organisms in the near future.
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Affiliation(s)
- Bartosz Turkowyd
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | | | - Julia Wörtz
- Department of Biology II, Ulm University, Ulm, Germany
| | - Ella Shtifman Segal
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Moshe Mevarech
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Iain G. Duggin
- The ithree Institute, University of Technology Sydney, Ultimo, NSW, Australia
| | | | - Ulrike Endesfelder
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
- Department of Physics, Mellon College of Science, Carnegie-Mellon University, Pittsburgh, PA, United States
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Marshall AP, Shirley JD, Carlson EE. Enzyme-targeted fluorescent small-molecule probes for bacterial imaging. Curr Opin Chem Biol 2020; 57:155-165. [PMID: 32799037 DOI: 10.1016/j.cbpa.2020.05.012] [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] [Received: 01/12/2020] [Revised: 05/27/2020] [Accepted: 05/29/2020] [Indexed: 12/26/2022]
Abstract
Molecular imaging methods to visualize myriad biochemical processes in bacteria have traditionally been dependent upon molecular biology techniques to incorporate fluorescent biomolecules (e.g., fusion proteins). Such methods have been instrumental in our understanding of how bacteria function but are not without drawbacks, including potential perturbation to native protein expression and function. To overcome these limitations, the use of fluorescent small-molecule probes has gained much attention. Here, we highlight examples from the recent literature that showcase the utility of small-molecule probes for the fluorescence imaging of bacterial cells, including electrophilic, metabolic, and enzyme-activated probes. Although the use of these types of compounds for bacterial imaging is still relatively new, the selected examples demonstrate the exciting potential of these critical tools in the exploration of bacterial physiology.
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Affiliation(s)
- Andrew P Marshall
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Joshua D Shirley
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Erin E Carlson
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States; Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, United States; Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, United States.
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Vlazaki M, Huber J, Restif O. Integrating mathematical models with experimental data to investigate the within-host dynamics of bacterial infections. Pathog Dis 2020; 77:5704399. [PMID: 31942996 PMCID: PMC6986552 DOI: 10.1093/femspd/ftaa001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 01/13/2020] [Indexed: 12/23/2022] Open
Abstract
Bacterial infections still constitute a major cause of mortality and morbidity worldwide. The unavailability of therapeutics, antimicrobial resistance and the chronicity of infections due to incomplete clearance contribute to this phenomenon. Despite the progress in antimicrobial and vaccine development, knowledge about the effect that therapeutics have on the host–bacteria interactions remains incomplete. Insights into the characteristics of bacterial colonization and migration between tissues and the relationship between replication and host- or therapeutically induced killing can enable efficient design of treatment approaches. Recently, innovative experimental techniques have generated data enabling the qualitative characterization of aspects of bacterial dynamics. Here, we argue that mathematical modeling as an adjunct to experimental data can enrich the biological insight that these data provide. However, due to limited interdisciplinary training, efforts to combine the two remain limited. To promote this dialogue, we provide a categorization of modeling approaches highlighting their relationship to data generated by a range of experimental techniques in the area of in vivo bacterial dynamics. We outline common biological themes explored using mathematical models with case studies across all pathogen classes. Finally, this review advocates multidisciplinary integration to improve our mechanistic understanding of bacterial infections and guide the use of existing or new therapies.
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Affiliation(s)
- Myrto Vlazaki
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, CB3 0ES, Cambridge, UK
| | - John Huber
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, CB3 0ES, Cambridge, UK
| | - Olivier Restif
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, CB3 0ES, Cambridge, UK
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