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Botha JL, van Heerden B, Krüger TPJ. Advanced analysis of single-molecule spectroscopic data. BIOPHYSICAL REPORTS 2024; 4:100173. [PMID: 39097230 DOI: 10.1016/j.bpr.2024.100173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 06/29/2024] [Accepted: 07/25/2024] [Indexed: 08/05/2024]
Abstract
We present Full SMS, a multipurpose graphical user interface (GUI)-based software package for analyzing single-molecule spectroscopy (SMS) data. SMS typically delivers multiparameter data-such as fluorescence brightness, lifetime, and spectra-of molecular- or nanometer-scale particles such as single dye molecules, quantum dots, or fluorescently labeled biological macromolecules. Full SMS allows an unbiased statistical analysis of fluorescence brightness through level resolution and clustering, analysis of fluorescence lifetimes through decay fitting, as well as the calculation of second-order correlation functions and the display of fluorescence spectra and raster-scan images. Additional features include extensive data filtering options, a custom HDF5-based file format, and flexible data export options. The software is open source and written in Python but GUI based so it may be used without any programming knowledge. A multiprocess architecture was employed for computational efficiency. The software is also designed to be easily extendable to include additional import data types and analysis capabilities.
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Affiliation(s)
- Joshua L Botha
- Department of Physics, University of Pretoria, Pretoria, Gauteng, South Africa
| | - Bertus van Heerden
- Department of Physics, University of Pretoria, Pretoria, Gauteng, South Africa; Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, Gauteng, South Africa; National Institute of Theoretical and Computational Sciences (NITheCS), South Africa
| | - Tjaart P J Krüger
- Department of Physics, University of Pretoria, Pretoria, Gauteng, South Africa; Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, Gauteng, South Africa; National Institute of Theoretical and Computational Sciences (NITheCS), South Africa.
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2
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Coke K, Johnson MJ, Robinson JB, Rettie AJE, Miller TS, Shearing PR. Illuminating Polysulfide Distribution in Lithium Sulfur Batteries; Tracking Polysulfide Shuttle Using Operando Optical Fluorescence Microscopy. ACS APPLIED MATERIALS & INTERFACES 2024; 16. [PMID: 38598420 PMCID: PMC11056927 DOI: 10.1021/acsami.3c14612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 03/01/2024] [Accepted: 03/08/2024] [Indexed: 04/12/2024]
Abstract
High-energy-density lithium sulfur (Li-S) batteries suffer heavily from the polysulfide shuttle effect, a result of the dissolution and transport of intermediate polysulfides from the cathode, into the electrolyte, and onto the anode, leading to rapid cell degradation. If this primary mechanism of cell failure is to be overcome, the distribution, dynamics, and degree of polysulfide transport must first be understood in depth. In this work, operando optical fluorescence microscope imaging of optically accessible Li-S cells is shown to enable real-time qualitative visualization of the spatial distribution of lithium polysulfides, both within the electrolyte and porous cathode. Quantitative determinations of spatial concentration are also possible at a low enough concentration. The distribution throughout cycling is monitored, including direct observation of polysulfide shuttling to the anode and consequent dendrite formation. This was enabled through the optimization of a selective fluorescent dye, verified to fluoresce proportionally with concentration of polysulfides within Li-S cells. This ability to directly and conveniently track the spatial distribution of soluble polysulfide intermediates in Li-S battery electrolytes, while the cell operates, has the potential to have a widespread impact across the field, for example, by enabling the influence of a variety of polysulfide mitigation strategies to be assessed and optimized, including in this work the LiNO3 additive.
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Affiliation(s)
- Kofi Coke
- Electrochemical
Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, U.K.
| | - Michael J. Johnson
- Electrochemical
Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, U.K.
| | - James B. Robinson
- Electrochemical
Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, U.K.
- The
Faraday Institution, Quad One, Becquerel Avenue, Harwell Campus, Didcot OX11 ORA, U.K.
- Advanced
Propulsion Lab, UCL East, University College
London, London E15 2JE, U.K.
| | - Alexander J. E. Rettie
- Electrochemical
Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, U.K.
- The
Faraday Institution, Quad One, Becquerel Avenue, Harwell Campus, Didcot OX11 ORA, U.K.
- Advanced
Propulsion Lab, UCL East, University College
London, London E15 2JE, U.K.
| | - Thomas S. Miller
- Electrochemical
Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, U.K.
- The
Faraday Institution, Quad One, Becquerel Avenue, Harwell Campus, Didcot OX11 ORA, U.K.
| | - Paul R. Shearing
- The
Faraday Institution, Quad One, Becquerel Avenue, Harwell Campus, Didcot OX11 ORA, U.K.
- Department
of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, U.K.
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3
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Radler P, Loose M. A dynamic duo: Understanding the roles of FtsZ and FtsA for Escherichia coli cell division through in vitro approaches. Eur J Cell Biol 2024; 103:151380. [PMID: 38218128 DOI: 10.1016/j.ejcb.2023.151380] [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: 07/25/2023] [Revised: 12/22/2023] [Accepted: 12/24/2023] [Indexed: 01/15/2024] Open
Abstract
Bacteria divide by binary fission. The protein machine responsible for this process is the divisome, a transient assembly of more than 30 proteins in and on the surface of the cytoplasmic membrane. Together, they constrict the cell envelope and remodel the peptidoglycan layer to eventually split the cell into two. For Escherichia coli, most molecular players involved in this process have probably been identified, but obtaining the quantitative information needed for a mechanistic understanding can often not be achieved from experiments in vivo alone. Since the discovery of the Z-ring more than 30 years ago, in vitro reconstitution experiments have been crucial to shed light on molecular processes normally hidden in the complex environment of the living cell. In this review, we summarize how rebuilding the divisome from purified components - or at least parts of it - have been instrumental to obtain the detailed mechanistic understanding of the bacterial cell division machinery that we have today.
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Affiliation(s)
- Philipp Radler
- Institute for Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria; University of Vienna, Djerassiplatz 1, 1030 Wien, Austria.
| | - Martin Loose
- Institute for Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria.
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4
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Liyanage SH, Yan M. Maltose-Derivatized Fluorescence Turn-On Imaging Probe for Bacteria Detection. ACS Infect Dis 2023; 9:2560-2571. [PMID: 37936289 DOI: 10.1021/acsinfecdis.3c00403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
We report a maltose-derivatized fluorescence turn-on imaging probe, Mal-Cz, to detect E. coli and Staphylococci. The fluorescence turn-on is achieved through an intramolecular C-H insertion reaction of the perfluoroaryl azide-functionalized carbazole to give a fluorescent product. Confocal fluorescence microscopy confirmed the successful uptake of Mal-Cz by E. coli and Staphylococci upon photoactivation. The Mal-Cz probe could selectively detect E. coli and S. epidermidis in the presence of P. aeruginosa and M. smegmatis without interference from these bacteria. Both the photoactivation and bacteria detection can be accomplished using a hand-held UV lamp at 365 nm, with the limit of detection of 103 CFU/mL by the naked eye. Mal-Cz could also be used to detect E. coli and S. epidermidis spiked in milk by the naked eye under a hand-held UV lamp. The uptake of Mal-Cz requires metabolically active bacteria: the uptake was reduced in stationary phase bacteria and was diminished in bacteria that were killed by heating or treating with antibiotics or sodium azide. The uptake decreased with increasing concentration of added free maltose, indicating that Mal-Cz hijacked the maltose uptake pathways. In E. coli, the maltose transport systems, including maltoporin LamB, maltose binding protein MBP, and the maltose ATP binding cassette (ABC) transporter MalFGK2, are all critical for the transport of Mal-Cz. The uptake was diminished in the deletion mutants ΔLamB, ΔMalE, ΔMalF, and ΔMalK.
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Affiliation(s)
- Sajani H Liyanage
- Department of Chemistry, University of Massachusetts Lowell, Lowell, Massachusetts 01854, United States
| | - Mingdi Yan
- Department of Chemistry, University of Massachusetts Lowell, Lowell, Massachusetts 01854, United States
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5
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Gritchenko AS, Kalmykov AS, Kulnitskiy BA, Vainer YG, Wang SP, Kang B, Melentiev PN, Balykin VI. Ultra-bright and narrow-band emission from Ag atomic sized nanoclusters in a self-assembled plasmonic resonator. NANOSCALE 2022; 14:9910-9917. [PMID: 35781487 DOI: 10.1039/d2nr01650h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We have proposed, implemented and investigated a novel, efficient quantum emitter based on an atomic-sized Ag nanocluster in a plasmonic resonator. The quantum emitter enables the realization of: (1) ultra-bright fluorescence, (2) narrow-band emission down to 4 nm, (3) ultra-short fluorescence lifetime. The fluorescence cross-section of a quantum emitter is on the order of σ ∼ 10-14 cm2, which is comparable to the largest fluorescence cross-sections of dye molecules and quantum dots, and enables a light source with a record high intensity known only for plasmon nanolasers. The results presented suggest a unique method for fabricating nanoprobes with high brightness and wavelength-tunable spectrally narrow fluorescence, which is needed for multiplex diagnostics and detection of substances at extremely low concentrations.
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Affiliation(s)
| | | | - Boris A Kulnitskiy
- Technological Institute for Superhard and Novel Carbon Materials, Moscow, Troitsk 108840, Russia
- Moscow Institute of Physics and Technology, Moscow reg., Dolgoprudny, 141700, Russia
| | - Yuri G Vainer
- Institute of Spectroscopy RAS, Moscow, Troitsk 108840, Russia.
| | - Shao-Peng Wang
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 163 Xianlin Road, Nanjing 210023, P. R. China
| | - Bin Kang
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 163 Xianlin Road, Nanjing 210023, P. R. China
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6
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Biswas S, Chen Z, Karslake JD, Farhat A, Ames A, Raiymbek G, Freddolino PL, Biteen JS, Ragunathan K. HP1 oligomerization compensates for low-affinity H3K9me recognition and provides a tunable mechanism for heterochromatin-specific localization. SCIENCE ADVANCES 2022; 8:eabk0793. [PMID: 35857444 PMCID: PMC9269880 DOI: 10.1126/sciadv.abk0793] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 05/24/2022] [Indexed: 05/31/2023]
Abstract
HP1 proteins traverse a complex and crowded chromatin landscape to bind with low affinity but high specificity to histone H3K9 methylation (H3K9me) and form transcriptionally inactive genomic compartments called heterochromatin. Here, we visualize single-molecule dynamics of an HP1 homolog, the fission yeast Swi6, in its native chromatin environment. By tracking single Swi6 molecules, we identify mobility states that map to discrete biochemical intermediates. Using Swi6 mutants that perturb H3K9me recognition, oligomerization, or nucleic acid binding, we determine how each biochemical property affects protein dynamics. We estimate that Swi6 recognizes H3K9me3 with ~94-fold specificity relative to unmodified nucleosomes in living cells. While nucleic acid binding competes with Swi6 oligomerization, as few as four tandem chromodomains can overcome these inhibitory effects to facilitate Swi6 localization at heterochromatin formation sites. Our studies indicate that HP1 oligomerization is essential to form dynamic, higher-order complexes that outcompete nucleic acid binding to enable specific H3K9me recognition.
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Affiliation(s)
- Saikat Biswas
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ziyuan Chen
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48104, USA
| | - Joshua D. Karslake
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48104, USA
| | - Ali Farhat
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Amanda Ames
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gulzhan Raiymbek
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Peter L. Freddolino
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Julie S. Biteen
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48104, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48104, USA
| | - Kaushik Ragunathan
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
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7
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Imaging Minimal Bacteria at the Nanoscale: a Reliable and Versatile Process to Perform Single-Molecule Localization Microscopy in Mycoplasmas. Microbiol Spectr 2022; 10:e0064522. [PMID: 35638916 PMCID: PMC9241803 DOI: 10.1128/spectrum.00645-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Mycoplasmas are the smallest free-living organisms. These bacteria are important models for both fundamental and synthetic biology, owing to their highly reduced genomes. They are also relevant in the medical and veterinary fields, as they are pathogenic to both humans and most livestock species. Mycoplasma cells have minute sizes, often in the 300- to 800-nm range. As these dimensions are close to the diffraction limit of visible light, fluorescence imaging in mycoplasmas is often poorly informative. Recently developed superresolution imaging techniques can break this diffraction limit, improving the imaging resolution by an order of magnitude and offering a new nanoscale vision of the organization of these bacteria. These techniques have, however, not been applied to mycoplasmas before. Here, we describe an efficient and reliable protocol to perform single-molecule localization microscopy (SMLM) imaging in mycoplasmas. We provide a polyvalent transposon-based system to express the photoconvertible fluorescent protein mEos3.2, enabling photo-activated localization microscopy (PALM) in most Mycoplasma species. We also describe the application of direct stochastic optical reconstruction microscopy (dSTORM). We showcase the potential of these techniques by studying the subcellular localization of two proteins of interest. Our work highlights the benefits of state-of-the-art microscopy techniques for mycoplasmology and provides an incentive to further the development of SMLM strategies to study these organisms in the future. IMPORTANCE Mycoplasmas are important models in biology, as well as highly problematic pathogens in the medical and veterinary fields. The very small sizes of these bacteria, well below a micron, limits the usefulness of traditional fluorescence imaging methods, as their resolution limit is similar to the dimensions of the cells. Here, to bypass this issue, we established a set of state-of-the-art superresolution microscopy techniques in a wide range of Mycoplasma species. We describe two strategies: PALM, based on the expression of a specific photoconvertible fluorescent protein, and dSTORM, based on fluorophore-coupled antibody labeling. With these methods, we successfully performed single-molecule imaging of proteins of interest at the surface of the cells and in the cytoplasm, at lateral resolutions well below 50 nm. Our work paves the way toward a better understanding of mycoplasma biology through imaging of subcellular structures at the nanometer scale.
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8
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Sołtys K, Tarczewska A, Bystranowska D, Sozańska N. Getting Closer to Decrypting the Phase Transitions of Bacterial Biomolecules. Biomolecules 2022; 12:907. [PMID: 35883463 PMCID: PMC9312465 DOI: 10.3390/biom12070907] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/24/2022] [Accepted: 06/26/2022] [Indexed: 12/31/2022] Open
Abstract
Liquid-liquid phase separation (LLPS) of biomolecules has emerged as a new paradigm in cell biology, and the process is one proposed mechanism for the formation of membraneless organelles (MLOs). Bacterial cells have only recently drawn strong interest in terms of studies on both liquid-to-liquid and liquid-to-solid phase transitions. It seems that these processes drive the formation of prokaryotic cellular condensates that resemble eukaryotic MLOs. In this review, we present an overview of the key microbial biomolecules that undergo LLPS, as well as the formation and organization of biomacromolecular condensates within the intracellular space. We also discuss the current challenges in investigating bacterial biomacromolecular condensates. Additionally, we highlight a summary of recent knowledge about the participation of bacterial biomolecules in a phase transition and provide some new in silico analyses that can be helpful for further investigations.
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Affiliation(s)
- Katarzyna Sołtys
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland; (A.T.); (D.B.); (N.S.)
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9
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Spang A, Mahendrarajah TA, Offre P, Stairs CW. Evolving Perspective on the Origin and Diversification of Cellular Life and the Virosphere. Genome Biol Evol 2022; 14:evac034. [PMID: 35218347 PMCID: PMC9169541 DOI: 10.1093/gbe/evac034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2022] [Indexed: 11/14/2022] Open
Abstract
The tree of life (TOL) is a powerful framework to depict the evolutionary history of cellular organisms through time, from our microbial origins to the diversification of multicellular eukaryotes that shape the visible biosphere today. During the past decades, our perception of the TOL has fundamentally changed, in part, due to profound methodological advances, which allowed a more objective approach to studying organismal and viral diversity and led to the discovery of major new branches in the TOL as well as viral lineages. Phylogenetic and comparative genomics analyses of these data have, among others, revolutionized our understanding of the deep roots and diversity of microbial life, the origin of the eukaryotic cell, eukaryotic diversity, as well as the origin, and diversification of viruses. In this review, we provide an overview of some of the recent discoveries on the evolutionary history of cellular organisms and their viruses and discuss a variety of complementary techniques that we consider crucial for making further progress in our understanding of the TOL and its interconnection with the virosphere.
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Affiliation(s)
- Anja Spang
- Department of Marine Microbiology and Biogeochemistry, NIOZ, Royal Netherlands Institute for Sea Research, Utrecht University, Den Burg, The Netherlands
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Tara A Mahendrarajah
- Department of Marine Microbiology and Biogeochemistry, NIOZ, Royal Netherlands Institute for Sea Research, Utrecht University, Den Burg, The Netherlands
| | - Pierre Offre
- Department of Marine Microbiology and Biogeochemistry, NIOZ, Royal Netherlands Institute for Sea Research, Utrecht University, Den Burg, The Netherlands
| | - Courtney W Stairs
- Department of Biology, Microbiology research group, Lund University, Lund, Sweden
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10
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Single molecule tracking of bacterial cell surface cytochromes reveals dynamics that impact long-distance electron transport. Proc Natl Acad Sci U S A 2022; 119:e2119964119. [PMID: 35503913 PMCID: PMC9171617 DOI: 10.1073/pnas.2119964119] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Multiheme cytochromes in Shewanella oneidensis MR-1 transport electrons across the cell wall, in a process called extracellular electron transfer. These electron conduits can also enable electron transport along and between cells. While the underlying mechanism is thought to involve a combination of electron hopping and lateral diffusion of cytochromes along membranes, these diffusive dynamics have never been observed in vivo. Here, we observe the mobility of quantum dot-labeled cytochromes on living cell surfaces and membrane nanowires, quantify their diffusion with single-particle tracking techniques, and simulate the contribution of these dynamics to electron transport. This work reveals the impact of redox molecule dynamics on bacterial electron transport, with implications for understanding and harnessing this process in the environment and bioelectronics. Using a series of multiheme cytochromes, the metal-reducing bacterium Shewanella oneidensis MR-1 can perform extracellular electron transfer (EET) to respire redox-active surfaces, including minerals and electrodes outside the cell. While the role of multiheme cytochromes in transporting electrons across the cell wall is well established, these cytochromes were also recently found to facilitate long-distance (micrometer-scale) redox conduction along outer membranes and across multiple cells bridging electrodes. Recent studies proposed that long-distance conduction arises from the interplay of electron hopping and cytochrome diffusion, which allows collisions and electron exchange between cytochromes along membranes. However, the diffusive dynamics of the multiheme cytochromes have never been observed or quantified in vivo, making it difficult to assess their hypothesized contribution to the collision-exchange mechanism. Here, we use quantum dot labeling, total internal reflection fluorescence microscopy, and single-particle tracking to quantify the lateral diffusive dynamics of the outer membrane-associated decaheme cytochromes MtrC and OmcA, two key components of EET in S. oneidensis. We observe confined diffusion behavior for both quantum dot-labeled MtrC and OmcA along cell surfaces (diffusion coefficients DMtrC = 0.0192 ± 0.0018 µm2/s, DOmcA = 0.0125 ± 0.0024 µm2/s) and the membrane extensions thought to function as bacterial nanowires. We find that these dynamics can trace a path for electron transport via overlap of cytochrome trajectories, consistent with the long-distance conduction mechanism. The measured dynamics inform kinetic Monte Carlo simulations that combine direct electron hopping and redox molecule diffusion, revealing significant electron transport rates along cells and membrane nanowires.
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11
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Budiardjo SJ, Stevens JJ, Calkins AL, Ikujuni AP, Wimalasena VK, Firlar E, Case DA, Biteen JS, Kaelber JT, Slusky JSG. Colicin E1 opens its hinge to plug TolC. eLife 2022; 11:73297. [PMID: 35199644 PMCID: PMC9020818 DOI: 10.7554/elife.73297] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 02/21/2022] [Indexed: 12/02/2022] Open
Abstract
The double membrane architecture of Gram-negative bacteria forms a barrier that is impermeable to most extracellular threats. Bacteriocin proteins evolved to exploit the accessible, surface-exposed proteins embedded in the outer membrane to deliver cytotoxic cargo. Colicin E1 is a bacteriocin produced by, and lethal to, Escherichia coli that hijacks the outer membrane proteins (OMPs) TolC and BtuB to enter the cell. Here, we capture the colicin E1 translocation domain inside its membrane receptor, TolC, by high-resolution cryo-electron microscopy to obtain the first reported structure of a bacteriocin bound to TolC. Colicin E1 binds stably to TolC as an open hinge through the TolC pore—an architectural rearrangement from colicin E1’s unbound conformation. This binding is stable in live E. coli cells as indicated by single-molecule fluorescence microscopy. Finally, colicin E1 fragments binding to TolC plug the channel, inhibiting its native efflux function as an antibiotic efflux pump, and heightening susceptibility to three antibiotic classes. In addition to demonstrating that these protein fragments are useful starting points for developing novel antibiotic potentiators, this method could be expanded to other colicins to inhibit other OMP functions. Bacteria are constantly warring with each other for space and resources. As a result, they have developed a range of molecular weapons to poison, damage or disable other cells. For instance, bacteriocins are proteins that can latch onto structures at the surface of enemy bacteria and push toxins through their outer membrane. Bacteria are increasingly resistant to antibiotics, representing a growing concern for modern healthcare. One way that they are able to survive is by using ‘efflux pumps’ studded through their external membranes to expel harmful drugs before these can cause damage. Budiardjo et al. wanted to test whether bacteriocins could interfere with this defence mechanism by blocking efflux pumps. Bacteriocins are usually formed of binding elements (which recognise specific target proteins) and of a ‘killer tail’ that can stab the cell. Experiments showed that the binding parts of a bacteriocin could effectively ‘plug’ efflux pumps in Escherichia coli bacteria: high-resolution molecular microscopy revealed how the bacteriocin fragment binds to the pump, while fluorescent markers showed that it attached to the surface of E. coli and stopped the efflux pumps from working. As a result, lower amounts of antibiotics were necessary to kill the bacteria when bacteriocins were present. The work by Budiardjo et al. could lead to new ways to combat bacteria that will reduce the need for current antibiotics. In the future, bacteriocins could also be harnessed to target other proteins than efflux pumps, allowing scientists to manipulate a range of bacterial processes.
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Affiliation(s)
- S Jimmy Budiardjo
- Center for Computational Biology, University of Kansas, Lawrence, United States
| | - Jacqueline J Stevens
- Department of Molecular Biosciences, University of Kansas, Lawrence, United States
| | - Anna L Calkins
- Department of Chemistry, University of Michigan, Ann Arbor, United States
| | - Ayotunde P Ikujuni
- Department of Molecular Biosciences, University of Kansas, Lawrence, United States
| | | | - Emre Firlar
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, United States
| | - David A Case
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, United States
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, United States
| | - Jason T Kaelber
- Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, United States
| | - Joanna S G Slusky
- Center for Computational Biology, University of Kansas, Lawrence, United States
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12
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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: 5] [Impact Index Per Article: 2.5] [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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13
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Beaufay F, Amemiya HM, Guan J, Basalla J, Meinen BA, Chen Z, Mitra R, Bardwell JCA, Biteen JS, Vecchiarelli AG, Freddolino PL, Jakob U. Polyphosphate drives bacterial heterochromatin formation. SCIENCE ADVANCES 2021; 7:eabk0233. [PMID: 34936433 PMCID: PMC10954037 DOI: 10.1126/sciadv.abk0233] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 11/10/2021] [Indexed: 06/14/2023]
Abstract
Heterochromatin is most often associated with eukaryotic organisms. Yet, bacteria also contain areas with densely protein-occupied chromatin that appear to silence gene expression. One nucleoid-associated silencing factor is the conserved protein Hfq. Although seemingly nonspecific in its DNA binding properties, Hfq is strongly enriched at AT-rich DNA regions, characteristic of prophages and mobile genetic elements. Here, we demonstrate that polyphosphate (polyP), an ancient and highly conserved polyanion, is essential for the site-specific DNA binding properties of Hfq in bacteria. Absence of polyP markedly alters the DNA binding profile of Hfq, causes unsolicited prophage and transposon mobilization, and increases mutagenesis rates and DNA damage–induced cell death. In vitro reconstitution of the system revealed that Hfq and polyP interact with AT-rich DNA sequences and form phase-separated condensates, a process that is mediated by the intrinsically disordered C-terminal extensions of Hfq. We propose that polyP serves as a newly identified driver of heterochromatin formation in bacteria.
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Affiliation(s)
- Francois Beaufay
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Haley M. Amemiya
- Cellular and Molecular Biology Program, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
- Department of Computational medicine and Bioinformatics, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Jian Guan
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Joseph Basalla
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Ben A. Meinen
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
| | - Ziyuan Chen
- Biophysics Program, University of Michigan, Ann Arbor, MI, USA
| | - Rishav Mitra
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - James C. A. Bardwell
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
| | - Julie S. Biteen
- Biophysics Program, University of Michigan, Ann Arbor, MI, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Anthony G. Vecchiarelli
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Peter L. Freddolino
- Department of Biological Chemistry, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Ursula Jakob
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Biological Chemistry, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
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14
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Chia HE, Koebke KJ, Rangarajan AA, Koropatkin NM, Marsh ENG, Biteen JS. New Orange Ligand-Dependent Fluorescent Reporter for Anaerobic Imaging. ACS Chem Biol 2021; 16:2109-2115. [PMID: 34652894 PMCID: PMC11180495 DOI: 10.1021/acschembio.1c00391] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Bilin-binding fluorescent proteins like UnaG-bilirubin are noncovalent ligand-dependent reporters for oxygen-free microscopy but are restricted to blue and far-red fluorescence. Here we describe a high-throughput screening approach to provide a new UnaG-ligand pair that can be excited in the 532 nm green excitation microscopy channel. We identified a novel orange UnaG-ligand pair that maximally emits at 581 nm. Whereas the benzothiazole-based ligand itself is nominally fluorescent, the compound binds UnaG with high affinity (Kd = 3 nM) to induce a 2.5-fold fluorescence intensity enhancement and a 10 nm red shift. We demonstrated this pair in the anaerobic fluorescence microscopy of the prevalent gut bacterium Bacteroides thetaiotaomicron and in Escherichia coli. This UnaG-ligand pair can also be coupled to IFP2.0-biliverdin to differentiate cells in mixed-species two-color imaging. Our results demonstrate the versatility of the UnaG ligand-binding pocket and extend the ability to image cells at longer wavelengths in anoxic environments.
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Affiliation(s)
- Hannah E Chia
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Karl J Koebke
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Aathmaja A Rangarajan
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Nicole M Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - E Neil G Marsh
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Julie S Biteen
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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15
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Gao Z, Zhang W, Chang R, Zhang S, Yang G, Zhao G. Liquid-Liquid Phase Separation: Unraveling the Enigma of Biomolecular Condensates in Microbial Cells. Front Microbiol 2021; 12:751880. [PMID: 34759902 PMCID: PMC8573418 DOI: 10.3389/fmicb.2021.751880] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 09/06/2021] [Indexed: 12/12/2022] Open
Abstract
Numerous examples of microbial phase-separated biomolecular condensates have now been identified following advances in fluorescence imaging and single molecule microscopy technologies. The structure, function, and potential applications of these microbial condensates are currently receiving a great deal of attention. By neatly compartmentalizing proteins and their interactors in membrane-less organizations while maintaining free communication between these macromolecules and the external environment, microbial cells are able to achieve enhanced metabolic efficiency. Typically, these condensates also possess the ability to rapidly adapt to internal and external changes. The biological functions of several phase-separated condensates in small bacterial cells show evolutionary convergence with the biological functions of their eukaryotic paralogs. Artificial microbial membrane-less organelles are being constructed with application prospects in biocatalysis, biosynthesis, and biomedicine. In this review, we provide an overview of currently known biomolecular condensates driven by liquid-liquid phase separation (LLPS) in microbial cells, and we elaborate on their biogenesis mechanisms and biological functions. Additionally, we highlight the major challenges and future research prospects in studying microbial LLPS.
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Affiliation(s)
| | | | | | | | - Guiwen Yang
- College of Life Science, Shandong Normal University, Jinan, China
| | - Guoyan Zhao
- College of Life Science, Shandong Normal University, Jinan, China
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16
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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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17
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Singh MK, Kenney LJ. Super-resolution imaging of bacterial pathogens and visualization of their secreted effectors. FEMS Microbiol Rev 2021; 45:5911101. [PMID: 32970796 DOI: 10.1093/femsre/fuaa050] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 09/17/2020] [Indexed: 12/13/2022] Open
Abstract
Recent advances in super-resolution imaging techniques, together with new fluorescent probes have enhanced our understanding of bacterial pathogenesis and their interplay within the host. In this review, we provide an overview of what these techniques have taught us about the bacterial lifestyle, the nucleoid organization, its complex protein secretion systems, as well as the secreted virulence factors.
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Affiliation(s)
- Moirangthem Kiran Singh
- Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Linda J Kenney
- Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
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18
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Cheng X, Yin W. Probing Biosensing Interfaces With Single Molecule Localization Microscopy (SMLM). Front Chem 2021; 9:655324. [PMID: 33996750 PMCID: PMC8117217 DOI: 10.3389/fchem.2021.655324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/16/2021] [Indexed: 11/23/2022] Open
Abstract
Far field single molecule localization microscopy (SMLM) has been established as a powerful tool to study biological structures with resolution far below the diffraction limit of conventional light microscopy. In recent years, the applications of SMLM have reached beyond traditional cellular imaging. Nanostructured interfaces are enriched with information that determines their function, playing key roles in applications such as chemical catalysis and biological sensing. SMLM enables detailed study of interfaces at an individual molecular level, allowing measurements of reaction kinetics, and detection of rare events not accessible to ensemble measurements. This paper provides an update to the progress made to the use of SMLM in characterizing nanostructured biointerfaces, focusing on practical aspects, recent advances, and emerging opportunities from an analytical chemistry perspective.
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Affiliation(s)
- Xiaoyu Cheng
- State Key Laboratory for Modern Optical Instrumentations, National Engineering Research Center of Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, China
| | - Wei Yin
- Core Facilities, School of Medicine, Zhejiang University, Hangzhou, China
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19
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Azaldegui CA, Vecchiarelli AG, Biteen JS. The emergence of phase separation as an organizing principle in bacteria. Biophys J 2021; 120:1123-1138. [PMID: 33186556 PMCID: PMC8059088 DOI: 10.1016/j.bpj.2020.09.023] [Citation(s) in RCA: 105] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/10/2020] [Accepted: 09/15/2020] [Indexed: 12/12/2022] Open
Abstract
Recent investigations in bacteria suggest that membraneless organelles play a crucial role in the subcellular organization of bacterial cells. However, the biochemical functions and assembly mechanisms of these compartments have not yet been completely characterized. This article assesses the current methodologies used in the study of membraneless organelles in bacteria, highlights the limitations in determining the phase of complexes in cells that are typically an order of magnitude smaller than a eukaryotic cell, and identifies gaps in our current knowledge about the functional role of membraneless organelles in bacteria. Liquid-liquid phase separation (LLPS) is one proposed mechanism for membraneless organelle assembly. Overall, we outline the framework to evaluate LLPS in vivo in bacteria, we describe the bacterial systems with proposed LLPS activity, and we comment on the general role LLPS plays in bacteria and how it may regulate cellular function. Lastly, we provide an outlook for super-resolution microscopy and single-molecule tracking as tools to assess condensates in bacteria.
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Affiliation(s)
| | - Anthony G Vecchiarelli
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan.
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan.
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20
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Abstract
Optical studies of single molecules have taught us much over the past three decades, but these individual quantum-mechanical objects continue to have promise as probes of nanoscale structure and dynamics in complex systems.
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Affiliation(s)
- W E Moerner
- Departments of Chemistry and of Applied Physics (courtesy), Stanford University, Stanford, California 94305-4401, United States
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21
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Cambré A, Aertsen A. Bacterial Vivisection: How Fluorescence-Based Imaging Techniques Shed a Light on the Inner Workings of Bacteria. Microbiol Mol Biol Rev 2020; 84:e00008-20. [PMID: 33115939 PMCID: PMC7599038 DOI: 10.1128/mmbr.00008-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The rise in fluorescence-based imaging techniques over the past 3 decades has improved the ability of researchers to scrutinize live cell biology at increased spatial and temporal resolution. In microbiology, these real-time vivisections structurally changed the view on the bacterial cell away from the "watery bag of enzymes" paradigm toward the perspective that these organisms are as complex as their eukaryotic counterparts. Capitalizing on the enormous potential of (time-lapse) fluorescence microscopy and the ever-extending pallet of corresponding probes, initial breakthroughs were made in unraveling the localization of proteins and monitoring real-time gene expression. However, later it became clear that the potential of this technique extends much further, paving the way for a focus-shift from observing single events within bacterial cells or populations to obtaining a more global picture at the intra- and intercellular level. In this review, we outline the current state of the art in fluorescence-based vivisection of bacteria and provide an overview of important case studies to exemplify how to use or combine different strategies to gain detailed information on the cell's physiology. The manuscript therefore consists of two separate (but interconnected) parts that can be read and consulted individually. The first part focuses on the fluorescent probe pallet and provides a perspective on modern methodologies for microscopy using these tools. The second section of the review takes the reader on a tour through the bacterial cell from cytoplasm to outer shell, describing strategies and methods to highlight architectural features and overall dynamics within cells.
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Affiliation(s)
- Alexander Cambré
- KU Leuven, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, Leuven, Belgium
| | - Abram Aertsen
- KU Leuven, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, Leuven, Belgium
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22
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Möckl L, Moerner WE. Super-resolution Microscopy with Single Molecules in Biology and Beyond-Essentials, Current Trends, and Future Challenges. J Am Chem Soc 2020; 142:17828-17844. [PMID: 33034452 PMCID: PMC7582613 DOI: 10.1021/jacs.0c08178] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Indexed: 12/31/2022]
Abstract
Single-molecule super-resolution microscopy has developed from a specialized technique into one of the most versatile and powerful imaging methods of the nanoscale over the past two decades. In this perspective, we provide a brief overview of the historical development of the field, the fundamental concepts, the methodology required to obtain maximum quantitative information, and the current state of the art. Then, we will discuss emerging perspectives and areas where innovation and further improvement are needed. Despite the tremendous progress, the full potential of single-molecule super-resolution microscopy is yet to be realized, which will be enabled by the research ahead of us.
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Affiliation(s)
- Leonhard Möckl
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - W. E. Moerner
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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23
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Lucidi M, Hristu R, Nichele L, Stanciu GA, Tranca DE, Holban AM, Visca P, Stanciu SG, Cincotti G. STED nanoscopy of KK114-stained pathogenic bacteria. JOURNAL OF BIOPHOTONICS 2020; 13:e202000097. [PMID: 32483852 DOI: 10.1002/jbio.202000097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/11/2020] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
Super-resolution microscopy techniques can provide answers to still pending questions on prokaryotic organisms but are yet to be used at their full potential for this purpose. To address this, we evaluate the ability of the rhodamine-like KK114 dye to label various types of bacteria, to enable imaging of fine structural details with stimulated emission depletion microscopy (STED). We assessed fluorescent labeling with KK114 for eleven Gram-positive and Gram-negative bacterial species and observed that this contrast agent binds to their cell membranes. Significant differences in the labeling outputs were noticed across the tested bacterial species, but importantly, KK114-staining allowed the observation of subtle nanometric cell details in some cases. For example, a helix pattern resembling a cytoskeleton arrangement was detected in Bacillus subtilis. Furthermore, we found that KK114 easily penetrates the membrane of bacterial microorganism that lost their viability, which can be useful to discriminate between living and dead cells.
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Affiliation(s)
| | - Radu Hristu
- Center for Microscopy - Microanalysis and Information Processing, University Politehnica of Bucharest, Bucharest, Romania
| | | | - George A Stanciu
- Center for Microscopy - Microanalysis and Information Processing, University Politehnica of Bucharest, Bucharest, Romania
| | - Denis E Tranca
- Center for Microscopy - Microanalysis and Information Processing, University Politehnica of Bucharest, Bucharest, Romania
| | - Alina Maria Holban
- Microbiology and Immunology Department, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Paolo Visca
- Department of Sciences, University Roma Tre, Rome, Italy
| | - Stefan G Stanciu
- Center for Microscopy - Microanalysis and Information Processing, University Politehnica of Bucharest, Bucharest, Romania
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24
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Wu Y, Ruan H, Dong Z, Zhao R, Yu J, Tang X, Kou X, Zhang X, Wu M, Luo F, Yuan J, Fang X. Fluorescent Polymer Dot-Based Multicolor Stimulated Emission Depletion Nanoscopy with a Single Laser Beam Pair for Cellular Tracking. Anal Chem 2020; 92:12088-12096. [PMID: 32867488 DOI: 10.1021/acs.analchem.0c02821] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Stimulated emission depletion (STED) nanoscopy provides subdiffraction resolution while preserving the benefits of fluorescence confocal microscopy in live-cell imaging. However, there are several challenges for multicolor STED nanoscopy, including sophisticated microscopy architectures, fast photobleaching, and cross talk of fluorescent probes. Here, we introduce two types of nanoscale fluorescent semiconducting polymer dots (Pdots) with different emission wavelengths: CNPPV (poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-(1-cyanovinylene-1,4-phenylene)]) Pdots and PDFDP (poly[{9,9-dihexyl-2,7-bis(1-cyanovinylene)fluorene}-alt-co-{2,5-bis (N,N'-diphenylamino)-1,4-phenylene}]) Pdots, for dual-color STED bioimaging and cellular tracking. Besides bright fluorescence, strong photostability, and easy bioconjugation, these Pdots have large Stokes shifts, which make it possible to share both excitation and depletion beams, thus requiring only a single pair of laser beams for the dual-color STED imaging. Long-term tracking of cellular organelles by the Pdots has been achieved in living cells, and the dynamic interaction of endosomes derived from clathrin-mediated and caveolae-mediated endocytic pathways has been monitored for the first time to propose their interaction models. These results demonstrate the promise of Pdots as excellent probes for live-cell multicolor STED nanoscopy.
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Affiliation(s)
- Yayun Wu
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hefei Ruan
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Zaizai Dong
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Rong Zhao
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianqiang Yu
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaojun Tang
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaolong Kou
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Xing Zhang
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Manchen Wu
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fang Luo
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinghe Yuan
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaohong Fang
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China.,Institute of Cancer and Basic Medicine, Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
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25
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Al-Husini N, Tomares DT, Pfaffenberger ZJ, Muthunayake NS, Samad MA, Zuo T, Bitar O, Aretakis JR, Bharmal MHM, Gega A, Biteen JS, Childers WS, Schrader JM. BR-Bodies Provide Selectively Permeable Condensates that Stimulate mRNA Decay and Prevent Release of Decay Intermediates. Mol Cell 2020; 78:670-682.e8. [PMID: 32343944 PMCID: PMC7245546 DOI: 10.1016/j.molcel.2020.04.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 12/16/2019] [Accepted: 03/30/2020] [Indexed: 12/22/2022]
Abstract
Biomolecular condensates play a key role in organizing RNAs and proteins into membraneless organelles. Bacterial RNP-bodies (BR-bodies) are a biomolecular condensate containing the RNA degradosome mRNA decay machinery, but the biochemical function of such organization remains poorly defined. Here, we define the RNA substrates of BR-bodies through enrichment of the bodies followed by RNA sequencing (RNA-seq). We find that long, poorly translated mRNAs, small RNAs, and antisense RNAs are the main substrates, while rRNA, tRNA, and other conserved non-coding RNAs (ncRNAs) are excluded from these bodies. BR-bodies stimulate the mRNA decay rate of enriched mRNAs, helping to reshape the cellular mRNA pool. We also observe that BR-body formation promotes complete mRNA decay, avoiding the buildup of toxic endo-cleaved mRNA decay intermediates. The combined selective permeability of BR-bodies for both enzymes and substrates together with the stimulation of the sub-steps of mRNA decay provide an effective organization strategy for bacterial mRNA decay.
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MESH Headings
- Caulobacter crescentus/genetics
- Caulobacter crescentus/growth & development
- Caulobacter crescentus/metabolism
- Endoribonucleases/genetics
- Endoribonucleases/metabolism
- Escherichia coli/genetics
- Escherichia coli/growth & development
- Escherichia coli/metabolism
- Humans
- Multienzyme Complexes/genetics
- Multienzyme Complexes/metabolism
- Organelles/genetics
- Organelles/metabolism
- Polyribonucleotide Nucleotidyltransferase/genetics
- Polyribonucleotide Nucleotidyltransferase/metabolism
- RNA Helicases/genetics
- RNA Helicases/metabolism
- RNA Stability
- RNA, Antisense/genetics
- RNA, Antisense/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- RNA, Small Untranslated/genetics
- RNA, Small Untranslated/metabolism
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- RNA, Untranslated/genetics
- RNA, Untranslated/metabolism
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Affiliation(s)
- Nadra Al-Husini
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Dylan T Tomares
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | | | | | - Mohammad A Samad
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Tiancheng Zuo
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Obaidah Bitar
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - James R Aretakis
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | | | - Alisa Gega
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA.
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26
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Chia HE, Zuo T, Koropatkin NM, Marsh ENG, Biteen JS. Imaging living obligate anaerobic bacteria with bilin-binding fluorescent proteins. CURRENT RESEARCH IN MICROBIAL SCIENCES 2020; 1:1-6. [PMID: 33313576 PMCID: PMC7731933 DOI: 10.1016/j.crmicr.2020.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Conventional fluorescent proteins like GFP are restricted to aerobic environments. Bilin-binding fluorescent proteins (BBFPs) enable live-cell imaging of anaerobes. We implemented BBFPs to fluorescently label prevalent gut microbiome species. The UnaG and IFP2.0 BBFPs can be used in multi-species multicolor microscopy.
Fluorescent tools such as green fluorescent protein (GFP) have been used extensively as reporters in biochemistry and microbiology, but GFP and other conventional fluorescent proteins are restricted to aerobic environments. This limitation precludes fluorescence studies of anaerobic ecologies including polymicrobial communities in the human gut microbiome and in soil microbiomes, which profoundly affect health, disease, and the environment. To address this limitation, we describe the first implementation of two bilin-binding fluorescent proteins (BBFPs), UnaG and IFP2.0, as oxygen-independent fluorescent labels for live-cell imaging in anaerobic bacteria. Expression of UnaG or IFP2.0 in the prevalent gut bacterium Bacteroides thetaiotaomicron (B. theta) results in detectable fluorescence upon the addition of the bilirubin or biliverdin ligand, even in anaerobic conditions. Furthermore, these BBFPs can be used in two-color imaging to differentiate cells expressing either UnaG or IFP2.0; UnaG and IFP2.0 can also be used to distinguish B. theta from other common gut bacterial species in mixed-culture live-cell imaging. BBFPs are promising fluorescent tools for live-cell imaging investigations of otherwise inaccessible anaerobic polymicrobial communities.
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Affiliation(s)
- Hannah E Chia
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, USA
| | - Tiancheng Zuo
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Nicole M Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - E Neil G Marsh
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA.,Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Julie S Biteen
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, USA.,Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
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27
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Kner P, Manley S, Shechtman Y, Stallinga S. 25 th Anniversary of STED Microscopy and the 20 th Anniversary of SIM: feature introduction. BIOMEDICAL OPTICS EXPRESS 2020; 11:1707-1711. [PMID: 32206437 PMCID: PMC7075616 DOI: 10.1364/boe.391490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Indexed: 06/10/2023]
Abstract
This feature issue commemorating 25 years of STED microscopy and 20 years of SIM is intended to highlight the incredible progress and growth in the field of superresolution microscopy since Stefan Hell and Jan Wichmann published the article Breaking the diffraction resolution limit by stimulated emission: stimulated-emission-depletion fluorescence microscopy in Optics Letters in 1994.
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Affiliation(s)
- Peter Kner
- School of Electrical and Computer Engineering, University of Georgia, Athens, GA 30602, USA
| | - Suliana Manley
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Yoav Shechtman
- Biomedical Engineering Department, Technion, 32000 Haifa, Israel
| | - Sjoerd Stallinga
- Quantitative Imaging Group, Delft University of Technology, Delft, Netherlands
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28
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Endesfelder U. From single bacterial cell imaging towards in vivo single-molecule biochemistry studies. Essays Biochem 2019; 63:187-196. [PMID: 31197072 PMCID: PMC6610453 DOI: 10.1042/ebc20190002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/17/2019] [Accepted: 05/22/2019] [Indexed: 12/12/2022]
Abstract
Bacteria as single-cell organisms are important model systems to study cellular mechanisms and functions. In recent years and with the help of advanced fluorescence microscopy techniques, immense progress has been made in characterizing and quantifying the behavior of single bacterial cells on the basis of molecular interactions and assemblies in the complex environment of live cultures. Importantly, single-molecule imaging enables the in vivo determination of the stoichiometry and molecular architecture of subcellular structures, yielding detailed, quantitative, spatiotemporally resolved molecular maps and unraveling dynamic heterogeneities and subpopulations on the subcellular level. Nevertheless, open challenges remain. Here, we review the past and current status of the field, discuss example applications and give insights into future trends.
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Affiliation(s)
- Ulrike Endesfelder
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
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29
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Isaacoff BP, Li Y, Lee SA, Biteen JS. SMALL-LABS: Measuring Single-Molecule Intensity and Position in Obscuring Backgrounds. Biophys J 2019; 116:975-982. [PMID: 30846363 DOI: 10.1016/j.bpj.2019.02.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 01/27/2019] [Accepted: 02/07/2019] [Indexed: 11/19/2022] Open
Abstract
Single-molecule and super-resolution imaging relies on successful, sensitive, and accurate detection of the emission from fluorescent molecules. Yet, despite the widespread adoption of super-resolution microscopies, single-molecule data processing algorithms can fail to provide accurate measurements of the brightness and position of molecules in the presence of backgrounds that fluctuate significantly over time and space. Thus, samples or experiments that include obscuring backgrounds can severely, or even completely, hinder this process. To date, no general data analysis approach to this problem has been introduced that is capable of removing obscuring backgrounds for a wide variety of experimental modalities. To address this need, we present the Single-Molecule Accurate LocaLization by LocAl Background Subtraction (SMALL-LABS) algorithm, which can be incorporated into existing single-molecule and super-resolution analysis packages to accurately locate and measure the intensity of single molecules, regardless of the shape or brightness of the background. Accurate background subtraction is enabled by separating the foreground from the background based on differences in the temporal variations of the foreground and the background (i.e., fluorophore blinking, bleaching, or moving). We detail the function of SMALL-LABS here, and we validate the SMALL-LABS algorithm on simulated data as well as real data from single-molecule imaging in living cells.
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Affiliation(s)
| | - Yilai Li
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan
| | - Stephen A Lee
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan.
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30
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Abstract
Time series obtained from time-dependent experiments contain rich information on kinetics and dynamics of the system under investigation. This work describes an unsupervised learning framework, along with the derivation of the necessary analytical expressions, for the analysis of Gaussian-distributed time series that exhibit discrete states. After the time series has been partitioned into segments in a model-free manner using the previously developed change-point (CP) method, this protocol starts with an agglomerative hierarchical clustering algorithm to classify the detected segments into possible states. The initial state clustering is further refined using an expectation-maximization (EM) procedure, and the number of states is determined by a Bayesian information criterion (BIC). Also introduced here is an achievement scalarization function, usually seen in artificial intelligence literature, for quantitatively assessing the performance of state determination. The statistical learning framework, which is comprised of three stages, detection of signal change, clustering, and number-of-state determination, was thoroughly characterized using simulated trajectories with random intensity segments that have no underlying kinetics, and its performance was critically evaluated. The application to experimental data is also demonstrated. The results suggested that this general framework, the implementation of which is based on firm theoretical foundations and does not require the imposition of any kinetics model, is powerful in determining the number of states, the parameters contained in each state, as well as the associated statistical significance.
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Affiliation(s)
- Hao Li
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - Haw Yang
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
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31
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Klein HL, Ang KKH, Arkin MR, Beckwitt EC, Chang YH, Fan J, Kwon Y, Morten MJ, Mukherjee S, Pambos OJ, El Sayyed H, Thrall ES, Vieira-da-Rocha JP, Wang Q, Wang S, Yeh HY, Biteen JS, Chi P, Heyer WD, Kapanidis AN, Loparo JJ, Strick TR, Sung P, Van Houten B, Niu H, Rothenberg E. Guidelines for DNA recombination and repair studies: Mechanistic assays of DNA repair processes. MICROBIAL CELL 2019; 6:65-101. [PMID: 30652106 PMCID: PMC6334232 DOI: 10.15698/mic2019.01.665] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Genomes are constantly in flux, undergoing changes due to recombination, repair and mutagenesis. In vivo, many of such changes are studies using reporters for specific types of changes, or through cytological studies that detect changes at the single-cell level. Single molecule assays, which are reviewed here, can detect transient intermediates and dynamics of events. Biochemical assays allow detailed investigation of the DNA and protein activities of each step in a repair, recombination or mutagenesis event. Each type of assay is a powerful tool but each comes with its particular advantages and limitations. Here the most commonly used assays are reviewed, discussed, and presented as the guidelines for future studies.
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Affiliation(s)
- Hannah L Klein
- New York University School of Medicine, Department of Biochemistry and Molecular Pharmacology, New York, NY 10016, USA
| | - Kenny K H Ang
- Small Molecule Discovery Center and Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143, USA
| | - Michelle R Arkin
- Small Molecule Discovery Center and Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143, USA
| | - Emily C Beckwitt
- Program in Molecular Biophysics and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA.,The University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, PA 15213, USA
| | - Yi-Hsuan Chang
- Institute of Biochemical Sciences, National Taiwan University, NO. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Jun Fan
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Youngho Kwon
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.,Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas 78229, USA
| | - Michael J Morten
- New York University School of Medicine, Department of Biochemistry and Molecular Pharmacology, New York, NY 10016, USA
| | - Sucheta Mukherjee
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA
| | - Oliver J Pambos
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Hafez El Sayyed
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Elizabeth S Thrall
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - João P Vieira-da-Rocha
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA
| | - Quan Wang
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Shuang Wang
- Ecole Normale Supérieure, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), CNRS, INSERM, PSL Research University, 75005 Paris, France.,Institut Jacques Monod, CNRS, UMR7592, University Paris Diderot, Sorbonne Paris Cité F-75205 Paris, France
| | - Hsin-Yi Yeh
- Institute of Biochemical Sciences, National Taiwan University, NO. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Julie S Biteen
- Departments of Chemistry and Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Peter Chi
- Institute of Biochemical Sciences, National Taiwan University, NO. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan.,Institute of Biological Chemistry, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Wolf-Dietrich Heyer
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA.,Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Achillefs N Kapanidis
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Joseph J Loparo
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Terence R Strick
- Ecole Normale Supérieure, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), CNRS, INSERM, PSL Research University, 75005 Paris, France.,Institut Jacques Monod, CNRS, UMR7592, University Paris Diderot, Sorbonne Paris Cité F-75205 Paris, France.,Programme Equipe Labellisées, Ligue Contre le Cancer, 75013 Paris, France
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.,Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas 78229, USA
| | - Bennett Van Houten
- Program in Molecular Biophysics and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA.,Program in Molecular Biophysics and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA.,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Hengyao Niu
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Eli Rothenberg
- New York University School of Medicine, Department of Biochemistry and Molecular Pharmacology, New York, NY 10016, USA
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32
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Li Y, Schroeder JW, Simmons LA, Biteen JS. Visualizing bacterial DNA replication and repair with molecular resolution. Curr Opin Microbiol 2018; 43:38-45. [PMID: 29197672 PMCID: PMC5984126 DOI: 10.1016/j.mib.2017.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/28/2017] [Accepted: 11/06/2017] [Indexed: 10/18/2022]
Abstract
Although DNA replication and repair in bacteria have been extensively studied for many decades, in recent years the development of single-molecule microscopy has provided a new perspective on these fundamental processes. Because single-molecule imaging super-resolves the nanometer-scale dynamics of molecules, and because single-molecule imaging is sensitive to heterogeneities within a sample, this nanoscopic microscopy technique measures the motions, localizations, and interactions of proteins in real time without averaging ensemble observations, both in vitro and in vivo. In this Review, we provide an overview of several recent single-molecule fluorescence microscopy studies on DNA replication and repair. These experiments have shown that, in both Escherichia coli and Bacillus subtilis the DNA replication proteins are highly dynamic. In particular, even highly processive replicative DNA polymerases exchange to and from the replication fork on the scale of a few seconds. Furthermore, single-molecule investigations of the DNA mismatch repair (MMR) pathway have measured the complex interactions between MMR proteins, replication proteins, and DNA. Single-molecule imaging will continue to improve our understanding of fundamental processes in bacteria including DNA replication and repair.
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Affiliation(s)
- Yilai Li
- University of Michigan, Ann Arbor, MI 48109, United States
| | - Jeremy W Schroeder
- University of Michigan, Ann Arbor, MI 48109, United States; University of Wisconsin, Madison, WI 53706, United States
| | - Lyle A Simmons
- University of Michigan, Ann Arbor, MI 48109, United States
| | - Julie S Biteen
- University of Michigan, Ann Arbor, MI 48109, United States.
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33
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Spatial organization and dynamics of RNase E and ribosomes in Caulobacter crescentus. Proc Natl Acad Sci U S A 2018; 115:E3712-E3721. [PMID: 29610352 DOI: 10.1073/pnas.1721648115] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We report the dynamic spatial organization of Caulobacter crescentus RNase E (RNA degradosome) and ribosomal protein L1 (ribosome) using 3D single-particle tracking and superresolution microscopy. RNase E formed clusters along the central axis of the cell, while weak clusters of ribosomal protein L1 were deployed throughout the cytoplasm. These results contrast with RNase E and ribosome distribution in Escherichia coli, where RNase E colocalizes with the cytoplasmic membrane and ribosomes accumulate in polar nucleoid-free zones. For both RNase E and ribosomes in Caulobacter, we observed a decrease in confinement and clustering upon transcription inhibition and subsequent depletion of nascent RNA, suggesting that RNA substrate availability for processing, degradation, and translation facilitates confinement and clustering. Importantly, RNase E cluster positions correlated with the subcellular location of chromosomal loci of two highly transcribed rRNA genes, suggesting that RNase E's function in rRNA processing occurs at the site of rRNA synthesis. Thus, components of the RNA degradosome and ribosome assembly are spatiotemporally organized in Caulobacter, with chromosomal readout serving as the template for this organization.
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34
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Abstract
Immunofluorescence microscopy is an invaluable tool for the study of biological processes at the cellular level. While the localization of surface-exposed antigens can easily be determined using fluorescent antibodies, localization of intracellular antigens requires permeabilization of the bacterial cell wall and membrane. Here, we describe an immunofluorescence protocol tailored specifically for Streptococcus pyogenes, applying the phage lysin PlyC for cell wall permeabilization. This protocol allows a high level of morphological preservation, suitable for high-resolution microscopy. With slight modification, this protocol could also be used for other Gram-positive pathogens.
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35
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Padilla NA, Rea MT, Foy M, Upadhyay SP, Desrochers KA, Derus T, Knapper KA, Hunter NH, Wood S, Hinton DA, Cavell AC, Masias AG, Goldsmith RH. Tracking Lithium Ions via Widefield Fluorescence Microscopy for Battery Diagnostics. ACS Sens 2017; 2:903-908. [PMID: 28750532 DOI: 10.1021/acssensors.7b00087] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Direct tracking of lithium ions with time and spatial resolution can provide an important diagnostic tool for understanding mechanisms in lithium ion batteries. A fluorescent indicator of lithium ions, 2-(2-hydroxyphenyl)naphthoxazole, was synthesized and used for real-time tracking of lithium ions via widefield fluorescence microscopy. The fluorophore can be excited with visible light and was shown to enable quantitative determination of the lithium ion diffusion constant in a microfluidic model system for a plasticized polymer electrolyte lithium battery. The use of widefield fluorescence microscopy for in situ tracking of lithium ions in batteries is discussed.
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Affiliation(s)
- Nicolas A. Padilla
- Department
of Chemistry, The University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Morgan T. Rea
- Department
of Chemistry, The University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Michael Foy
- Department
of Chemistry, The University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Sunil P. Upadhyay
- Department
of Chemistry, The University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Kyle A. Desrochers
- Department
of Chemistry, The University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Tyler Derus
- Department
of Chemistry, The University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Kassandra A. Knapper
- Department
of Chemistry, The University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | | | - Sharla Wood
- Department
of Chemistry, The University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Daniel A. Hinton
- Department
of Chemistry, The University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Andrew C. Cavell
- Department
of Chemistry, The University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Alvaro G. Masias
- Ford Motor Company, 2101 Village
Road, Dearborn, Michigan 48121, United States
| | - Randall H. Goldsmith
- Department
of Chemistry, The University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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36
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Abstract
The change point detection method ( Watkins , L. P. ; Yang , H. J. Phys. Chem. B 2005 , 109 , 617 ) allows the objective identification and isolation of abrupt changes along a data series. Because this method is grounded in statistical tests, it is particularly powerful for probing complex and noisy signals without artificially imposing a kinetics model. The original algorithm, however, has a time complexity of [Formula: see text], where N is the size of the data and is, therefore, limited in its scalability. This paper puts forth a parallelization of change point detection to address these time and memory constraints. This parallelization method was evaluated by applying it to changes in the mean of Gaussian-distributed data and found that time decreases superlinearly with respect to the number of processes (i.e., parallelization with two processes takes less than half of the time of one process). Moreover, there was minimal reduction in detection power. These results suggest that our parallelization algorithm is a viable scheme that can be implemented for other change point detection methods.
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Affiliation(s)
- Nancy Song
- Department of Chemistry, Princeton University, , Princeton, New Jersey 08544, United States
| | - Haw Yang
- Department of Chemistry, Princeton University, , Princeton, New Jersey 08544, United States
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37
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von Diezmann A, Shechtman Y, Moerner WE. Three-Dimensional Localization of Single Molecules for Super-Resolution Imaging and Single-Particle Tracking. Chem Rev 2017; 117:7244-7275. [PMID: 28151646 PMCID: PMC5471132 DOI: 10.1021/acs.chemrev.6b00629] [Citation(s) in RCA: 260] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Single-molecule super-resolution fluorescence microscopy and single-particle tracking are two imaging modalities that illuminate the properties of cells and materials on spatial scales down to tens of nanometers or with dynamical information about nanoscale particle motion in the millisecond range, respectively. These methods generally use wide-field microscopes and two-dimensional camera detectors to localize molecules to much higher precision than the diffraction limit. Given the limited total photons available from each single-molecule label, both modalities require careful mathematical analysis and image processing. Much more information can be obtained about the system under study by extending to three-dimensional (3D) single-molecule localization: without this capability, visualization of structures or motions extending in the axial direction can easily be missed or confused, compromising scientific understanding. A variety of methods for obtaining both 3D super-resolution images and 3D tracking information have been devised, each with their own strengths and weaknesses. These include imaging of multiple focal planes, point-spread-function engineering, and interferometric detection. These methods may be compared based on their ability to provide accurate and precise position information on single-molecule emitters with limited photons. To successfully apply and further develop these methods, it is essential to consider many practical concerns, including the effects of optical aberrations, field dependence in the imaging system, fluorophore labeling density, and registration between different color channels. Selected examples of 3D super-resolution imaging and tracking are described for illustration from a variety of biological contexts and with a variety of methods, demonstrating the power of 3D localization for understanding complex systems.
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Affiliation(s)
| | - Yoav Shechtman
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - W. E. Moerner
- Department of Chemistry, Stanford University, Stanford, CA 94305
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38
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Rowland DJ, Tuson HH, Biteen JS. Resolving Fast, Confined Diffusion in Bacteria with Image Correlation Spectroscopy. Biophys J 2017; 110:2241-51. [PMID: 27224489 DOI: 10.1016/j.bpj.2016.04.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 04/14/2016] [Accepted: 04/18/2016] [Indexed: 01/30/2023] Open
Abstract
By following single fluorescent molecules in a microscope, single-particle tracking (SPT) can measure diffusion and binding on the nanometer and millisecond scales. Still, although SPT can at its limits characterize the fastest biomolecules as they interact with subcellular environments, this measurement may require advanced illumination techniques such as stroboscopic illumination. Here, we address the challenge of measuring fast subcellular motion by instead analyzing single-molecule data with spatiotemporal image correlation spectroscopy (STICS) with a focus on measurements of confined motion. Our SPT and STICS analysis of simulations of the fast diffusion of confined molecules shows that image blur affects both STICS and SPT, and we find biased diffusion rate measurements for STICS analysis in the limits of fast diffusion and tight confinement due to fitting STICS correlation functions to a Gaussian approximation. However, we determine that with STICS, it is possible to correctly interpret the motion that blurs single-molecule images without advanced illumination techniques or fast cameras. In particular, we present a method to overcome the bias due to image blur by properly estimating the width of the correlation function by directly calculating the correlation function variance instead of using the typical Gaussian fitting procedure. Our simulation results are validated by applying the STICS method to experimental measurements of fast, confined motion: we measure the diffusion of cytosolic mMaple3 in living Escherichia coli cells at 25 frames/s under continuous illumination to illustrate the utility of STICS in an experimental parameter regime for which in-frame motion prevents SPT and tight confinement of fast diffusion precludes stroboscopic illumination. Overall, our application of STICS to freely diffusing cytosolic protein in small cells extends the utility of single-molecule experiments to the regime of fast confined diffusion without requiring advanced microscopy techniques.
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Affiliation(s)
- David J Rowland
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan
| | - Hannah H Tuson
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan.
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39
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Visualization and characterization of individual type III protein secretion machines in live bacteria. Proc Natl Acad Sci U S A 2017; 114:6098-6103. [PMID: 28533372 PMCID: PMC5468683 DOI: 10.1073/pnas.1705823114] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Type III protein secretion machines have evolved to deliver bacterially encoded effector proteins into eukaryotic cells. Although electron microscopy has provided a detailed view of these machines in isolation or fixed samples, little is known about their organization in live bacteria. Here we report the visualization and characterization of the Salmonella type III secretion machine in live bacteria by 2D and 3D single-molecule switching superresolution microscopy. This approach provided access to transient components of this machine, which previously could not be analyzed. We determined the subcellular distribution of individual machines, the stoichiometry of the different components of this machine in situ, and the spatial distribution of the substrates of this machine before secretion. Furthermore, by visualizing this machine in Salmonella mutants we obtained major insights into the machine's assembly. This study bridges a major resolution gap in the visualization of this nanomachine and may serve as a paradigm for the examination of other bacterially encoded molecular machines.
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40
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Progress and prospects for small-molecule probes of bacterial imaging. Nat Chem Biol 2017; 12:472-8. [PMID: 27315537 DOI: 10.1038/nchembio.2109] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 05/13/2016] [Indexed: 11/09/2022]
Abstract
Fluorescence microscopy is an essential tool for the exploration of cell growth, division, transcription and translation in eukaryotes and prokaryotes alike. Despite the rapid development of techniques to study bacteria, the size of these organisms (1-10 μm) and their robust and largely impenetrable cell envelope present major challenges in imaging experiments. Fusion-based strategies, such as attachment of the protein of interest to a fluorescent protein or epitope tag, are by far the most common means for examining protein localization and expression in prokaryotes. While valuable, the use of genetically encoded tags can result in mislocalization or altered activity of the desired protein, does not provide a readout of the catalytic state of enzymes and cannot enable visualization of many other important cellular components, such as peptidoglycan, lipids, nucleic acids or glycans. Here, we highlight the use of biomolecule-specific small-molecule probes for imaging in bacteria.
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41
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Lee SA, Ponjavic A, Siv C, Lee SF, Biteen JS. Nanoscopic Cellular Imaging: Confinement Broadens Understanding. ACS NANO 2016; 10:8143-8153. [PMID: 27602688 DOI: 10.1021/acsnano.6b02863] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In recent years, single-molecule fluorescence imaging has been reconciling a fundamental mismatch between optical microscopy and subcellular biophysics. However, the next step in nanoscale imaging in living cells can be accessed only by optical excitation confinement geometries. Here, we review three methods of confinement that can enable nanoscale imaging in living cells: excitation confinement by laser illumination with beam shaping; physical confinement by micron-scale geometries in bacterial cells; and nanoscale confinement by nanophotonics.
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Affiliation(s)
- Stephen A Lee
- Department of Chemistry, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - Aleks Ponjavic
- Department of Chemistry, Cambridge University , Cambridge CB2 1EW, United Kingdom
| | - Chanrith Siv
- Department of Chemistry, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - Steven F Lee
- Department of Chemistry, Cambridge University , Cambridge CB2 1EW, United Kingdom
| | - Julie S Biteen
- Department of Chemistry, University of Michigan , Ann Arbor, Michigan 48109, United States
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42
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Hsu SM, Wu FY, Cheng H, Huang YT, Hsieh YR, Tseng DTH, Yeh MY, Hung SC, Lin HC. Functional Supramolecular Polymers: A Fluorescent Microfibrous Network in a Supramolecular Hydrogel for High-Contrast Live Cell-Material Imaging in 3D Environments. Adv Healthc Mater 2016; 5:2406-12. [PMID: 27390271 DOI: 10.1002/adhm.201600342] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 05/20/2016] [Indexed: 12/21/2022]
Abstract
A new bottom-up strategy based on aromatic peptide amphiphile is developed for a high-contrast visualization of 3D live cell-material imaging-something that has been difficult to achieve previously because of the problems associated with the diffraction of light by the nanosized peptide materials and the aggregation-caused quenching of aggregated π-conjugated fluorophores in the nanostructures. This study reports an example of a novel supramolecular hydrogelator, naphthaleneimide-phenylalanine (NI-Phe), which forms a self-supporting hydrogel displaying a unique microfibrous network and promising aggregation-induced emission characteristics at pH 7.4. The storage modulus of the NI-Phe gel supports the mass of a cell for 3D cell culturing. This work illustrates a new dopant-free supramolecular approach, complementary to well-established doping procedures that should facilitate the development of live cell imaging in 3D scaffolding materials.
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Affiliation(s)
- Shu-Min Hsu
- Department of Materials Science and Engineering; National Chiao Tung University; Hsinchu 30010 Taiwan
| | - Fang-Yi Wu
- Department of Materials Science and Engineering; National Chiao Tung University; Hsinchu 30010 Taiwan
| | - Hsun Cheng
- Department of Materials Science and Engineering; National Chiao Tung University; Hsinchu 30010 Taiwan
| | - Yu-Tang Huang
- Department of Materials Science and Engineering; National Chiao Tung University; Hsinchu 30010 Taiwan
| | - Yi-Ru Hsieh
- Department of Materials Science and Engineering; National Chiao Tung University; Hsinchu 30010 Taiwan
| | - Dion Tzu-Huan Tseng
- Department of Materials Science and Engineering; National Chiao Tung University; Hsinchu 30010 Taiwan
| | - Mei-Yu Yeh
- Integrative Stem Cell Center; China Medical University Hospital; Taichung 40447 Taiwan
- Graduate Institute of Basic Medical Science; China Medical University; Taichung 40402 Taiwan
| | - Shih-Chieh Hung
- Integrative Stem Cell Center; China Medical University Hospital; Taichung 40447 Taiwan
- Graduate Institute of Clinical Medical Science; China Medical University; Taichung 40402 Taiwan
| | - Hsin-Chieh Lin
- Department of Materials Science and Engineering; National Chiao Tung University; Hsinchu 30010 Taiwan
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43
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Shuang B, Wang W, Shen H, Tauzin LJ, Flatebo C, Chen J, Moringo NA, Bishop LDC, Kelly KF, Landes CF. Generalized recovery algorithm for 3D super-resolution microscopy using rotating point spread functions. Sci Rep 2016; 6:30826. [PMID: 27488312 PMCID: PMC4973222 DOI: 10.1038/srep30826] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 07/11/2016] [Indexed: 01/17/2023] Open
Abstract
Super-resolution microscopy with phase masks is a promising technique for 3D imaging and tracking. Due to the complexity of the resultant point spread functions, generalized recovery algorithms are still missing. We introduce a 3D super-resolution recovery algorithm that works for a variety of phase masks generating 3D point spread functions. A fast deconvolution process generates initial guesses, which are further refined by least squares fitting. Overfitting is suppressed using a machine learning determined threshold. Preliminary results on experimental data show that our algorithm can be used to super-localize 3D adsorption events within a porous polymer film and is useful for evaluating potential phase masks. Finally, we demonstrate that parallel computation on graphics processing units can reduce the processing time required for 3D recovery. Simulations reveal that, through desktop parallelization, the ultimate limit of real-time processing is possible. Our program is the first open source recovery program for generalized 3D recovery using rotating point spread functions.
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Affiliation(s)
- Bo Shuang
- Department of Chemistry, Rice University, Houston, TX 77251, USA
| | - Wenxiao Wang
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77251, USA
| | - Hao Shen
- Department of Chemistry, Rice University, Houston, TX 77251, USA
| | | | | | - Jianbo Chen
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77251, USA
| | | | | | - Kevin F. Kelly
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77251, USA
| | - Christy F. Landes
- Department of Chemistry, Rice University, Houston, TX 77251, USA
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77251, USA
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44
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Moolman MC, Kerssemakers JWJ, Dekker NH. Quantitative Analysis of Intracellular Fluorescent Foci in Live Bacteria. Biophys J 2016; 109:883-91. [PMID: 26331246 DOI: 10.1016/j.bpj.2015.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 07/10/2015] [Accepted: 07/13/2015] [Indexed: 11/18/2022] Open
Abstract
Fluorescence microscopy has revolutionized in vivo cellular biology. Through the specific labeling of a protein of interest with a fluorescent protein, one is able to study movement and colocalization, and even count individual proteins in a live cell. Different algorithms exist to quantify the total intensity and position of a fluorescent focus. Although these algorithms have been rigorously studied for in vitro conditions, which are greatly different than the in-homogenous and variable cellular environments, their exact limits and applicability in the context of a live cell have not been thoroughly and systematically evaluated. In this study, we quantitatively characterize the influence of different background subtraction algorithms on several focus analysis algorithms. We use, to our knowledge, a novel approach to assess the sensitivity of the focus analysis algorithms to background removal, in which simulated and experimental data are combined to maintain full control over the sensitivity of a focus within a realistic background of cellular fluorescence. We demonstrate that the choice of algorithm and the corresponding error are dependent on both the brightness of the focus, and the cellular context. Expectedly, focus intensity estimation and localization accuracy suffer in all algorithms at low focus to background ratios, with the bacteroidal background subtraction in combination with the median excess algorithm, and the region of interest background subtraction in combination with a two-dimensional Gaussian fit algorithm, performing the best. We furthermore show that the choice of background subtraction algorithm is dependent on the expression level of the protein under investigation, and that the localization error is dependent on the distance of a focus from the bacterial edge and pole. Our results establish a set of guidelines for what signals can be analyzed to give a targeted spatial and intensity accuracy within a bacterial cell.
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Affiliation(s)
- M Charl Moolman
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands
| | - Jacob W J Kerssemakers
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands
| | - Nynke H Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands.
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45
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Tuson HH, Aliaj A, Brandes ER, Simmons LA, Biteen JS. Addressing the Requirements of High-Sensitivity Single-Molecule Imaging of Low-Copy-Number Proteins in Bacteria. Chemphyschem 2016; 17:1435-40. [PMID: 26888309 PMCID: PMC4894654 DOI: 10.1002/cphc.201600035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Indexed: 11/11/2022]
Abstract
Single-molecule fluorescence super-resolution imaging and tracking provide nanometer-scale information about subcellular protein positions and dynamics. These single-molecule imaging experiments can be very powerful, but they are best suited to high-copy number proteins where many measurements can be made sequentially in each cell. We describe artifacts associated with the challenge of imaging a protein expressed in only a few copies per cell. We image live Bacillus subtilis in a fluorescence microscope, and demonstrate that under standard single-molecule imaging conditions, unlabeled B. subtilis cells display punctate red fluorescent spots indistinguishable from the few PAmCherry fluorescent protein single molecules under investigation. All Bacillus species investigated were strongly affected by this artifact, whereas we did not find a significant number of these background sources in two other species we investigated, Enterococcus faecalis and Escherichia coli. With single-molecule resolution, we characterize the number, spatial distribution, and intensities of these impurity spots.
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Affiliation(s)
- Hannah H Tuson
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Alisa Aliaj
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Eileen R Brandes
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Lyle A Simmons
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA.
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46
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Haeusser DP, Margolin W. Splitsville: structural and functional insights into the dynamic bacterial Z ring. Nat Rev Microbiol 2016; 14:305-19. [PMID: 27040757 DOI: 10.1038/nrmicro.2016.26] [Citation(s) in RCA: 216] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Bacteria must divide to increase in number and colonize their niche. Binary fission is the most widespread means of bacterial cell division, but even this relatively simple mechanism has many variations on a theme. In most bacteria, the tubulin homologue FtsZ assembles into a ring structure, termed the Z ring, at the site of cytokinesis and recruits additional proteins to form a large protein machine - the divisome - that spans the membrane. In this Review, we discuss current insights into the regulation of the assembly of the Z ring and how the divisome drives membrane invagination and septal cell wall growth while flexibly responding to various cellular inputs.
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Affiliation(s)
- Daniel P Haeusser
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin Street, Houston, Texas 77030, USA.,Biology Department, Canisius College, 2001 Main Street, Buffalo, New York 14208, USA
| | - William Margolin
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin Street, Houston, Texas 77030, USA
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47
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Biteen JS, Blainey PC, Cardon ZG, Chun M, Church GM, Dorrestein PC, Fraser SE, Gilbert JA, Jansson JK, Knight R, Miller JF, Ozcan A, Prather KA, Quake SR, Ruby EG, Silver PA, Taha S, van den Engh G, Weiss PS, Wong GCL, Wright AT, Young TD. Tools for the Microbiome: Nano and Beyond. ACS NANO 2016; 10:6-37. [PMID: 26695070 DOI: 10.1021/acsnano.5b07826] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The microbiome presents great opportunities for understanding and improving the world around us and elucidating the interactions that compose it. The microbiome also poses tremendous challenges for mapping and manipulating the entangled networks of interactions among myriad diverse organisms. Here, we describe the opportunities, technical needs, and potential approaches to address these challenges, based on recent and upcoming advances in measurement and control at the nanoscale and beyond. These technical needs will provide the basis for advancing the largely descriptive studies of the microbiome to the theoretical and mechanistic understandings that will underpin the discipline of microbiome engineering. We anticipate that the new tools and methods developed will also be more broadly useful in environmental monitoring, medicine, forensics, and other areas.
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Affiliation(s)
- Julie S Biteen
- Department of Chemistry, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - Paul C Blainey
- Department of Biological Engineering, Massachusetts Institute of Technology , and Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02138, United States
| | - Zoe G Cardon
- The Ecosystems Center, Marine Biological Laboratory , Woods Hole, Massachusetts 02543-1015, United States
| | - Miyoung Chun
- The Kavli Foundation , Oxnard, California 93030, United States
| | - George M Church
- Wyss Institute for Biologically Inspired Engineering and Biophysics Program, Harvard University , Boston, Massachusetts 02115, United States
| | | | - Scott E Fraser
- Translational Imaging Center, University of Southern California , Molecular and Computational Biology, Los Angeles, California 90089, United States
| | - Jack A Gilbert
- Institute for Genomic and Systems Biology, Argonne National Laboratory , Argonne, Illinois 60439, United States
- Department of Ecology and Evolution and Department of Surgery, University of Chicago , Chicago, Illinois 60637, United States
| | - Janet K Jansson
- Earth and Biological Sciences Division, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | | | | | | | | | | | - Edward G Ruby
- Kewalo Marine Laboratory, University of Hawaii-Manoa , Honolulu, Hawaii 96813, United States
| | - Pamela A Silver
- Wyss Institute for Biologically Inspired Engineering and Biophysics Program, Harvard University , Boston, Massachusetts 02115, United States
| | - Sharif Taha
- The Kavli Foundation , Oxnard, California 93030, United States
| | - Ger van den Engh
- Center for Marine Cytometry , Concrete, Washington 98237, United States
- Instituto Milenio de Oceanografía, Universidad de Concepción , Concepción, Chile
| | | | | | - Aaron T Wright
- Earth and Biological Sciences Division, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
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48
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Tauzin LJ, Shen H, Moringo NA, Roddy MH, Bothof CA, Griesgraber GW, McNulty AK, Rasmussen JK, Landes CF. Variable surface transport modalities on functionalized nylon films revealed with single molecule spectroscopy. RSC Adv 2016. [DOI: 10.1039/c5ra25592a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Functionalization of separation membranes with ion-exchange ligands allows control of the surface mobility of protein molecules facilitating optimized membrane design.
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Affiliation(s)
| | - Hao Shen
- Department of Chemistry
- Rice University
- Houston
- USA
| | | | | | - Cathy A. Bothof
- 3M Corporate Research Laboratories
- 3M Center 201-3E-03
- St. Paul
- USA
| | | | - Amy K. McNulty
- 3M Corporate Research Laboratories
- 3M Center 201-3E-03
- St. Paul
- USA
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49
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King JE, Roberts IS. Bacterial Surfaces: Front Lines in Host-Pathogen Interaction. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 915:129-56. [PMID: 27193542 DOI: 10.1007/978-3-319-32189-9_10] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
All bacteria are bound by at least one membrane that acts as a barrier between the cell's interior and the outside environment. Surface components within and attached to the cell membrane are essential for ensuring that the overall homeostasis of the cell is maintained. However, many surface components of the bacterial cell also have an indispensable role mediating interactions of the bacteria with their immediate environment and as such are essential to the pathogenesis of infectious disease. During the course of an infection, bacterial pathogens will encounter many different ecological niches where environmental conditions such as salinity, temperature, pH, and the availability of nutrients fluctuate. It is the bacterial cell surface that is at the front-line of these host-pathogen interactions often protecting the bacterium from hostile surroundings but at the same time playing a critical role in the adherence to host tissues promoting colonization and subsequent infection. To deal effectively with the changing environments that pathogens may encounter in different ecological niches within the host many of the surface components of the bacterial cell are subject to phenotypic variation resulting in heterogeneous subpopulations of bacteria within the clonal population. This dynamic phenotypic heterogeneity ensures that at least a small fraction of the population will be adapted for a particular circumstance should it arise. Diversity within the clonal population has often been masked by studies on entire bacterial populations where it was often assumed genes were expressed in a uniform manner. This chapter, therefore, aims to highlight the non-uniformity in certain cell surface structures and will discuss the implication of this heterogeneity in bacterial-host interaction. Some of the recent advances in studying bacterial surface structures at the single cell level will also be reviewed.
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Affiliation(s)
- Jane E King
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK
| | - Ian S Roberts
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK.
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