1
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Fan J, El Sayyed H, Pambos OJ, Stracy M, Kyropoulos J, Kapanidis AN. RNA polymerase redistribution supports growth in E. coli strains with a minimal number of rRNA operons. Nucleic Acids Res 2023; 51:8085-8101. [PMID: 37351576 PMCID: PMC10450203 DOI: 10.1093/nar/gkad511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 05/24/2023] [Accepted: 06/02/2023] [Indexed: 06/24/2023] Open
Abstract
Bacterial transcription by RNA polymerase (RNAP) is spatially organized. RNAPs transcribing highly expressed genes locate in the nucleoid periphery, and form clusters in rich medium, with several studies linking RNAP clustering and transcription of rRNA (rrn). However, the nature of RNAP clusters and their association with rrn transcription remains unclear. Here we address these questions by using single-molecule tracking to monitor the subcellular distribution of mobile and immobile RNAP in strains with a heavily reduced number of chromosomal rrn operons (Δrrn strains). Strikingly, we find that the fraction of chromosome-associated RNAP (which is mainly engaged in transcription) is robust to deleting five or six of the seven chromosomal rrn operons. Spatial analysis in Δrrn strains showed substantial RNAP redistribution during moderate growth, with clustering increasing at cell endcaps, where the remaining rrn operons reside. These results support a model where RNAPs in Δrrn strains relocate to copies of the remaining rrn operons. In rich medium, Δrrn strains redistribute RNAP to minimize growth defects due to rrn deletions, with very high RNAP densities on rrn genes leading to genomic instability. Our study links RNAP clusters and rrn transcription, and offers insight into how bacteria maintain growth in the presence of only 1-2 rrn operons.
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Affiliation(s)
- Jun Fan
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731, China
| | - Hafez El Sayyed
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin building, University of Oxford, Sherrington Road, Oxford OX1 3QU, UK
| | - Oliver J Pambos
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin building, University of Oxford, Sherrington Road, Oxford OX1 3QU, UK
| | - Mathew Stracy
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Jingwen Kyropoulos
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Achillefs N Kapanidis
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin building, University of Oxford, Sherrington Road, Oxford OX1 3QU, UK
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2
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Yuan L, Straub H, Shishaeva L, Ren Q. Microfluidics for Biofilm Studies. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2023; 16:139-159. [PMID: 37314876 DOI: 10.1146/annurev-anchem-091522-103827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Biofilms are multicellular communities held together by a self-produced extracellular matrix and exhibit a set of properties that distinguish them from free-living bacteria. Biofilms are exposed to a variety of mechanical and chemical cues resulting from fluid motion and mass transport. Microfluidics provides the precise control of hydrodynamic and physicochemical microenvironments to study biofilms in general. In this review, we summarize the recent progress made in microfluidics-based biofilm research, including understanding the mechanism of bacterial adhesion and biofilm development, assessment of antifouling and antimicrobial properties, development of advanced in vitro infection models, and advancement in methods to characterize biofilms. Finally, we provide a perspective on the future direction of microfluidics-assisted biofilm research.
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Affiliation(s)
- Lu Yuan
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, China;
| | - Hervé Straub
- Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland;
| | - Liubov Shishaeva
- Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland;
| | - Qun Ren
- Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland;
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3
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Siu DMD, Lee KCM, Chung BMF, Wong JSJ, Zheng G, Tsia KK. Optofluidic imaging meets deep learning: from merging to emerging. LAB ON A CHIP 2023; 23:1011-1033. [PMID: 36601812 DOI: 10.1039/d2lc00813k] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Propelled by the striking advances in optical microscopy and deep learning (DL), the role of imaging in lab-on-a-chip has dramatically been transformed from a silo inspection tool to a quantitative "smart" engine. A suite of advanced optical microscopes now enables imaging over a range of spatial scales (from molecules to organisms) and temporal window (from microseconds to hours). On the other hand, the staggering diversity of DL algorithms has revolutionized image processing and analysis at the scale and complexity that were once inconceivable. Recognizing these exciting but overwhelming developments, we provide a timely review of their latest trends in the context of lab-on-a-chip imaging, or coined optofluidic imaging. More importantly, here we discuss the strengths and caveats of how to adopt, reinvent, and integrate these imaging techniques and DL algorithms in order to tailor different lab-on-a-chip applications. In particular, we highlight three areas where the latest advances in lab-on-a-chip imaging and DL can form unique synergisms: image formation, image analytics and intelligent image-guided autonomous lab-on-a-chip. Despite the on-going challenges, we anticipate that they will represent the next frontiers in lab-on-a-chip imaging that will spearhead new capabilities in advancing analytical chemistry research, accelerating biological discovery, and empowering new intelligent clinical applications.
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Affiliation(s)
- Dickson M D Siu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong.
| | - Kelvin C M Lee
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong.
| | - Bob M F Chung
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong
| | - Justin S J Wong
- Conzeb Limited, Hong Kong Science Park, Shatin, New Territories, Hong Kong
| | - Guoan Zheng
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, USA
| | - Kevin K Tsia
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong.
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong
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4
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Dhiman S, Andrian T, Gonzalez BS, Tholen MME, Wang Y, Albertazzi L. Can super-resolution microscopy become a standard characterization technique for materials chemistry? Chem Sci 2022; 13:2152-2166. [PMID: 35310478 PMCID: PMC8864713 DOI: 10.1039/d1sc05506b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 12/01/2021] [Indexed: 12/20/2022] Open
Abstract
The characterization of newly synthesized materials is a cornerstone of all chemistry and nanotechnology laboratories. For this purpose, a wide array of analytical techniques have been standardized and are used routinely by laboratories across the globe. With these methods we can understand the structure, dynamics and function of novel molecular architectures and their relations with the desired performance, guiding the development of the next generation of materials. Moreover, one of the challenges in materials chemistry is the lack of reproducibility due to improper publishing of the sample preparation protocol. In this context, the recent adoption of the reporting standard MIRIBEL (Minimum Information Reporting in Bio-Nano Experimental Literature) for material characterization and details of experimental protocols aims to provide complete, reproducible and reliable sample preparation for the scientific community. Thus, MIRIBEL should be immediately adopted in publications by scientific journals to overcome this challenge. Besides current standard spectroscopy and microscopy techniques, there is a constant development of novel technologies that aim to help chemists unveil the structure of complex materials. Among them super-resolution microscopy (SRM), an optical technique that bypasses the diffraction limit of light, has facilitated the study of synthetic materials with multicolor ability and minimal invasiveness at nanometric resolution. Although still in its infancy, the potential of SRM to unveil the structure, dynamics and function of complex synthetic architectures has been highlighted in pioneering reports during the last few years. Currently, SRM is a sophisticated technique with many challenges in sample preparation, data analysis, environmental control and automation, and moreover the instrumentation is still expensive. Therefore, SRM is currently limited to expert users and is not implemented in characterization routines. This perspective discusses the potential of SRM to transition from a niche technique to a standard routine method for material characterization. We propose a roadmap for the necessary developments required for this purpose based on a collaborative effort from scientists and engineers across disciplines.
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Affiliation(s)
- Shikha Dhiman
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology P. O. Box 513 5600 MB Eindhoven The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology P. O. Box 513 5600 MB Eindhoven The Netherlands
| | - Teodora Andrian
- Institute of Bioengineering of Catalonia (IBEC), Barcelona Institute of Science and Technology Barcelona Spain
| | - Beatriz Santiago Gonzalez
- Department of Biomedical Engineering, Institute of Complex Molecular Systems, Eindhoven University of Technology Eindhoven The Netherlands
| | - Marrit M E Tholen
- Department of Biomedical Engineering, Institute of Complex Molecular Systems, Eindhoven University of Technology Eindhoven The Netherlands
| | - Yuyang Wang
- Institute for Complex Molecular Systems, Eindhoven University of Technology P. O. Box 513 5600 MB Eindhoven The Netherlands
- Department of Applied Physics, Eindhoven University of Technology Postbus 513 5600 MB Eindhoven The Netherlands
| | - Lorenzo Albertazzi
- Institute of Bioengineering of Catalonia (IBEC), Barcelona Institute of Science and Technology Barcelona Spain
- Department of Biomedical Engineering, Institute of Complex Molecular Systems, Eindhoven University of Technology Eindhoven The Netherlands
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5
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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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6
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Biochip with multi-planar electrodes geometry for differentiation of non-spherical bioparticles in a microchannel. Sci Rep 2021; 11:11880. [PMID: 34088942 PMCID: PMC8178319 DOI: 10.1038/s41598-021-91109-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 05/21/2021] [Indexed: 02/04/2023] Open
Abstract
A biosensor capable of differentiating cells or other microparticles based on morphology finds significant biomedical applications. Examples may include morphological determination in the cellular division process, differentiation of bacterial cells, and cellular morphological variation in inflammation and cancer etc. Here, we present a novel integrated multi-planar microelectrodes geometry design that can distinguish a non-spherical individual particle flowing along a microchannel based on its electrical signature. We simulated multi-planar electrodes design in COMSOL Multiphysics and have shown that the changes in electrical field intensity corresponding to multiple particle morphologies can be distinguished. Our initial investigation has shown that top-bottom electrodes configuration produces significantly enhanced signal strength for a spherical particle as compared to co-planar configuration. Next, we integrated the co-planar and top-bottom configurations to develop a multi-planar microelectrode design capable of electrical impedance measurement at different spatial planes inside a microchannel by collecting multiple output signatures. We tested our integrated multi-planar electrode design with particles of different elliptical morphologies by gradually changing spherical particle dimensions to the non-spherical. The computed electrical signal ratio of non-spherical to spherical particle shows a very good correlation to predict the particle morphology. The biochip sensitivity is also found be independent of orientation of the particle flowing in the microchannel. Our integrated design will help develop the technology that will allow morphological analysis of various bioparticles in a microfluidic channel in the future.
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7
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Wang YK, Krasnopeeva E, Lin SY, Bai F, Pilizota T, Lo CJ. Comparison of Escherichia coli surface attachment methods for single-cell microscopy. Sci Rep 2019; 9:19418. [PMID: 31857669 PMCID: PMC6923479 DOI: 10.1038/s41598-019-55798-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 11/05/2019] [Indexed: 12/22/2022] Open
Abstract
For in vivo, single-cell imaging bacterial cells are commonly immobilised via physical confinement or surface attachment. Different surface attachment methods have been used both for atomic force and optical microscopy (including super resolution), and some have been reported to affect bacterial physiology. However, a systematic comparison of the effects these attachment methods have on the bacterial physiology is lacking. Here we present such a comparison for bacterium Escherichia coli, and assess the growth rate, size and intracellular pH of cells growing attached to different, commonly used, surfaces. We demonstrate that E. coli grow at the same rate, length and internal pH on all the tested surfaces when in the same growth medium. The result suggests that tested attachment methods can be used interchangeably when studying E. coli physiology.
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Affiliation(s)
- Yao-Kuan Wang
- Department of Physics and Graduate Institute of Biophysics, National Central University, Jhongli, Taiwan, 32001, Republic of China
| | - Ekaterina Krasnopeeva
- Centre for Synthetic and Systems Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Alexander Crum Brown Road, EH9 3FF, Edinburgh, UK
| | - Ssu-Yuan Lin
- Department of Physics and Graduate Institute of Biophysics, National Central University, Jhongli, Taiwan, 32001, Republic of China
| | - Fan Bai
- Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing, 100871, China
| | - Teuta Pilizota
- Centre for Synthetic and Systems Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Alexander Crum Brown Road, EH9 3FF, Edinburgh, UK.
| | - Chien-Jung Lo
- Department of Physics and Graduate Institute of Biophysics, National Central University, Jhongli, Taiwan, 32001, Republic of China.
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8
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Chitosan Films for Microfluidic Studies of Single Bacteria and Perspectives for Antibiotic Susceptibility Testing. mBio 2019; 10:mBio.01375-19. [PMID: 31431549 PMCID: PMC6703423 DOI: 10.1128/mbio.01375-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Current microfluidic techniques are powerful to study bacteria and determine their response to antibiotic treatment, but they are currently limited by their complex manipulation. Chitosan films are fully biocompatible and could thus be a viable replacement for existing commercial devices that currently use polylysine. Thus, the low cost of chitosan slides and their simple implementation make them highly versatile for research as well as clinical use. Single-cell microfluidics is a powerful method to study bacteria and determine their susceptibility to antibiotic treatment. Glass treatment by adhesive molecules is a potential solution to immobilize bacterial cells and perform microscopy, but traditional cationic polymers such as polylysine deeply affect bacterial physiology. In this work, we chemically characterized a class of chitosan polymers for their biocompatibility when adsorbed to glass. Chitosan chains of known length and composition allowed growth of Escherichia coli cells without any deleterious effects on cell physiology. Combined with a machine learning approach, this method could measure the antibiotic susceptibility of a diversity of clinical strains in less than 1 h and with higher accuracy than current methods. Finally, chitosan polymers also supported growth of Klebsiella pneumoniae, another bacterial pathogen of clinical significance.
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9
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Quantification and isolation of Bacillus subtilis spores using cell sorting and automated gating. PLoS One 2019; 14:e0219892. [PMID: 31356641 PMCID: PMC6663000 DOI: 10.1371/journal.pone.0219892] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 07/04/2019] [Indexed: 01/22/2023] Open
Abstract
The Gram-positive bacterium Bacillus subtilis is able to form endospores which have a variety of biotechnological applications. Due to this ability, B. subtilis is as well a model organism for cellular differentiation processes. Sporulating cultures of B. subtilis form sub-populations which include vegetative cells, sporulating cells and spores. In order to readily and rapidly quantify spore formation we employed flow cytometric and fluorescence activated cell sorting techniques in combination with nucleic acid fluorescent staining in order to investigate the distribution of sporulating cultures on a single cell level. Automated gating procedures using Gaussian mixture modeling (GMM) were employed to avoid subjective gating and allow for the simultaneous measurement of controls. We utilized the presented method for monitoring sporulation over time in germination deficient strains harboring different genome modifications. A decrease in the sporulation efficiency of strain Bs02018, utilized for the display of sfGFP on the spores surface was observed. On the contrary, a double knock-out mutant of the phosphatase gene encoding Spo0E and of the spore killing factor SkfA (Bs02025) exhibited the highest sporulation efficiency, as within 24 h of cultivation in sporulation medium, cultures of BS02025 already consisted of 80% spores as opposed to 18% for the control strain. We confirmed the identity of the different subpopulations formed during sporulation by employing sorting and microscopy.
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10
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DNA-Membrane Anchor Facilitates Efficient Chromosome Translocation at a Distance in Bacillus subtilis. mBio 2019; 10:mBio.01117-19. [PMID: 31239381 PMCID: PMC6593407 DOI: 10.1128/mbio.01117-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
To properly segregate their chromosomes, organisms tightly regulate the organization and dynamics of their DNA. Aspects of the process by which DNA is translocated during sporulation are not yet fully understood, such as what factors indirectly influence the activity of the motor protein SpoIIIE. In this work, we have shown that a DNA-membrane tether mediated by RacA contributes to the activity of SpoIIIE. Loss of RacA nearly doubles the time of translocation, despite the physically distinct locations these proteins and their activities occupy within the cell. This is a rare example of an explicit effect that DNA-membrane connections can have on cell physiology and demonstrates that distant changes to the state of the chromosome can influence motor proteins which act upon it. Chromosome segregation in sporulating Bacillus subtilis involves the tethering of sister chromosomes at opposite cell poles. RacA is known to mediate chromosome tethering by interacting with both centromere-like elements in the DNA and with DivIVA, a membrane protein which localizes to the cell poles. RacA has a secondary function in which it assists in nucleoid condensation. Here we demonstrate that, in addition to positioning and condensing the chromosome, RacA contributes to efficient transport of DNA by the chromosome segregation motor SpoIIIE. When RacA is deleted, one-quarter of cells fail to capture DNA in the nascent spore, yet 70% of cells fail to form viable spores without RacA. This discrepancy indicates that RacA possesses a role in sporulation beyond DNA capture and condensation. We observed that the mutant cells had reduced chromosome translocation into the forespore across the entire length of the chromosome, requiring nearly twice as much time to move a given DNA locus. Additionally, functional abolition of the RacA-DivIVA interaction reduced translocation to a similar degree as in a racA deletion strain, demonstrating the importance of the RacA-mediated tether in translocation and chromosome packaging during sporulation. We propose that the DNA-membrane anchor facilitates efficient translocation by SpoIIIE, not through direct protein-protein contacts but by virtue of physical effects on the chromosome that arise from anchoring DNA at a distance.
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11
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Buzalewicz I, Suchwałko A, Trzciński P, Sas-Paszt L, Sumorok B, Kowal K, Kozera R, Wieliczko A, Podbielska H. Integrated multi-channel optical system for bacteria characterization and its potential use for monitoring of environmental bacteria. BIOMEDICAL OPTICS EXPRESS 2019; 10:1165-1183. [PMID: 30891337 PMCID: PMC6420290 DOI: 10.1364/boe.10.001165] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 12/28/2018] [Accepted: 01/21/2019] [Indexed: 06/09/2023]
Abstract
The potential use of a novel multichannel optical system towards fast and non-destructive bacteria identification and its application for environmental bacteria characterisation on the strain level is presented. It is the first attempt to use the proposed optical method to study various bacteria species (Gram-negative, Gram-positive) commonly present in the environment. The novel configuration of the optical system enables multichannel examination of bacterial colonies and provides additional functionality such as registration of two-dimensional (2D) distribution of monochromatic transmission coefficient of examined colonies, what can be used as a novel optical signature for bacteria characterization. Performed statistical analysis indicates that it is possible to identify representatives of environmental soil bacteria on the species level with the 98.51% accuracy and in case of two strains of Rahnella aquatilis bacteria on the strain level with the 98.8% accuracy. The proposed method is an alternative to the currently used preliminary bacteria examination in environment safety control with the advantage of being fast, reliable, non-destructive and requiring minimal sample preparation.
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Affiliation(s)
- Igor Buzalewicz
- Bio-Optics Group, Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, 27 Wybrzeże S. Wyspiańskiego Street, Wroclaw, Poland
| | | | - Paweł Trzciński
- Rhizosphere Laboratory, Agrotechnical Department, Research Institute of Horticulture, 1/3 Konstytucji 3 Maja Street, Skierniewice, Poland
| | - Lidia Sas-Paszt
- Rhizosphere Laboratory, Agrotechnical Department, Research Institute of Horticulture, 1/3 Konstytucji 3 Maja Street, Skierniewice, Poland
| | - Beata Sumorok
- Rhizosphere Laboratory, Agrotechnical Department, Research Institute of Horticulture, 1/3 Konstytucji 3 Maja Street, Skierniewice, Poland
| | | | - Ryszard Kozera
- Faculty of Applied Informatics and Mathematics, Warsaw University of Life Sciences SGGW, 159 Nowoursynowska Street, Warsaw, Poland
- School of Computer Science and Software Engineering, University of Western Australia, 35 Stirling Highway, WA 6009 Crawley, Perth, Australia
| | - Alina Wieliczko
- Department of Epizootiology and Veterinary Administration with Clinic of Infectious Diseases, Wroclaw University of Environmental and Life Science, 45 Grunwaldzki Square, Wroclaw, Poland
| | - Halina Podbielska
- Bio-Optics Group, Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, 27 Wybrzeże S. Wyspiańskiego Street, Wroclaw, Poland
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12
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Trojanowski D, Hołówka J, Zakrzewska-Czerwińska J. Where and When Bacterial Chromosome Replication Starts: A Single Cell Perspective. Front Microbiol 2018; 9:2819. [PMID: 30534115 PMCID: PMC6275241 DOI: 10.3389/fmicb.2018.02819] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 11/02/2018] [Indexed: 12/18/2022] Open
Abstract
Bacterial chromosomes have a single, unique replication origin (named oriC), from which DNA synthesis starts. This study describes methods of visualizing oriC regions and the chromosome replication in single living bacterial cells in real-time. This review also discusses the impact of live cell imaging techniques on understanding of chromosome replication dynamics, particularly at the initiation step, in different species of bacteria.
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Affiliation(s)
- Damian Trojanowski
- Department of Molecular Microbiology, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Joanna Hołówka
- Department of Molecular Microbiology, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
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13
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Spahn CK, Glaesmann M, Grimm JB, Ayala AX, Lavis LD, Heilemann M. A toolbox for multiplexed super-resolution imaging of the E. coli nucleoid and membrane using novel PAINT labels. Sci Rep 2018; 8:14768. [PMID: 30282984 PMCID: PMC6170473 DOI: 10.1038/s41598-018-33052-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 09/21/2018] [Indexed: 11/09/2022] Open
Abstract
Maintenance of the bacterial homeostasis initially emanates from interactions between proteins and the bacterial nucleoid. Investigating their spatial correlation requires high spatial resolution, especially in tiny, highly confined and crowded bacterial cells. Here, we present super-resolution microscopy using a palette of fluorescent labels that bind transiently to either the membrane or the nucleoid of fixed E. coli cells. The presented labels are easily applicable, versatile and allow long-term single-molecule super-resolution imaging independent of photobleaching. The different spectral properties allow for multiplexed imaging in combination with other localisation-based super-resolution imaging techniques. As examples for applications, we demonstrate correlated super-resolution imaging of the bacterial nucleoid with the position of genetic loci, of nascent DNA in correlation to the entire nucleoid, and of the nucleoid of metabolically arrested cells. We furthermore show that DNA- and membrane-targeting labels can be combined with photoactivatable fluorescent proteins and visualise the nano-scale distribution of RNA polymerase relative to the nucleoid in drug-treated E. coli cells.
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Affiliation(s)
- Christoph K Spahn
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany
| | - Mathilda Glaesmann
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany
| | - Jonathan B Grimm
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia, 20147, USA
| | - Anthony X Ayala
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia, 20147, USA
| | - Luke D Lavis
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia, 20147, USA.
| | - Mike Heilemann
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany.
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14
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Paiè P, Martínez Vázquez R, Osellame R, Bragheri F, Bassi A. Microfluidic Based Optical Microscopes on Chip. Cytometry A 2018; 93:987-996. [PMID: 30211977 PMCID: PMC6220811 DOI: 10.1002/cyto.a.23589] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/23/2018] [Accepted: 07/25/2018] [Indexed: 12/21/2022]
Abstract
Last decade's advancements in optofluidics allowed obtaining an ever increasing integration of different functionalities in lab on chip devices to culture, analyze, and manipulate single cells and entire biological specimens. Despite the importance of optical imaging for biological sample monitoring in microfluidics, imaging is traditionally achieved by placing microfluidics channels in standard bench-top optical microscopes. Recently, the development of either integrated optical elements or lensless imaging methods allowed optical imaging techniques to be implemented in lab on chip systems, thus increasing their automation, compactness, and portability. In this review, we discuss known solutions to implement microscopes on chip that exploit different optical methods such as bright-field, phase contrast, holographic, and fluorescence microscopy.
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Affiliation(s)
- Petra Paiè
- Istituto di Fotonica e NanotecnologieConsiglio Nazionale dell RicerchePiazza Leonardo da Vinci 3220133 MilanItaly
| | - Rebeca Martínez Vázquez
- Istituto di Fotonica e NanotecnologieConsiglio Nazionale dell RicerchePiazza Leonardo da Vinci 3220133 MilanItaly
| | - Roberto Osellame
- Istituto di Fotonica e NanotecnologieConsiglio Nazionale dell RicerchePiazza Leonardo da Vinci 3220133 MilanItaly
- Dipartimento di FisicaPolitecnico di MilanoPiazza Leonardo da Vinci 3220133 MilanItaly
| | - Francesca Bragheri
- Istituto di Fotonica e NanotecnologieConsiglio Nazionale dell RicerchePiazza Leonardo da Vinci 3220133 MilanItaly
| | - Andrea Bassi
- Istituto di Fotonica e NanotecnologieConsiglio Nazionale dell RicerchePiazza Leonardo da Vinci 3220133 MilanItaly
- Dipartimento di FisicaPolitecnico di MilanoPiazza Leonardo da Vinci 3220133 MilanItaly
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15
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Szabo Q, Jost D, Chang JM, Cattoni DI, Papadopoulos GL, Bonev B, Sexton T, Gurgo J, Jacquier C, Nollmann M, Bantignies F, Cavalli G. TADs are 3D structural units of higher-order chromosome organization in Drosophila. SCIENCE ADVANCES 2018; 4:eaar8082. [PMID: 29503869 PMCID: PMC5829972 DOI: 10.1126/sciadv.aar8082] [Citation(s) in RCA: 176] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 01/30/2018] [Indexed: 05/19/2023]
Abstract
Deciphering the rules of genome folding in the cell nucleus is essential to understand its functions. Recent chromosome conformation capture (Hi-C) studies have revealed that the genome is partitioned into topologically associating domains (TADs), which demarcate functional epigenetic domains defined by combinations of specific chromatin marks. However, whether TADs are true physical units in each cell nucleus or whether they reflect statistical frequencies of measured interactions within cell populations is unclear. Using a combination of Hi-C, three-dimensional (3D) fluorescent in situ hybridization, super-resolution microscopy, and polymer modeling, we provide an integrative view of chromatin folding in Drosophila. We observed that repressed TADs form a succession of discrete nanocompartments, interspersed by less condensed active regions. Single-cell analysis revealed a consistent TAD-based physical compartmentalization of the chromatin fiber, with some degree of heterogeneity in intra-TAD conformations and in cis and trans inter-TAD contact events. These results indicate that TADs are fundamental 3D genome units that engage in dynamic higher-order inter-TAD connections. This domain-based architecture is likely to play a major role in regulatory transactions during DNA-dependent processes.
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Affiliation(s)
- Quentin Szabo
- Institute of Human Genetics, CNRS, Univ Montpellier, Montpellier, France
| | - Daniel Jost
- Univ Grenoble Alpes, CNRS, Grenoble INP, TIMC-IMAG, F-38000 Grenoble, France
| | - Jia-Ming Chang
- Institute of Human Genetics, CNRS, Univ Montpellier, Montpellier, France
| | - Diego I. Cattoni
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Univ Montpellier, 34090 Montpellier, France
| | | | - Boyan Bonev
- Institute of Human Genetics, CNRS, Univ Montpellier, Montpellier, France
| | - Tom Sexton
- Institute of Human Genetics, CNRS, Univ Montpellier, Montpellier, France
| | - Julian Gurgo
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Univ Montpellier, 34090 Montpellier, France
| | - Caroline Jacquier
- Institute of Human Genetics, CNRS, Univ Montpellier, Montpellier, France
| | - Marcelo Nollmann
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Univ Montpellier, 34090 Montpellier, France
| | - Frédéric Bantignies
- Institute of Human Genetics, CNRS, Univ Montpellier, Montpellier, France
- Corresponding author. (F.B.); (G.C.)
| | - Giacomo Cavalli
- Institute of Human Genetics, CNRS, Univ Montpellier, Montpellier, France
- Corresponding author. (F.B.); (G.C.)
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16
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Abstract
With single-molecule localization microscopy (SMLM) it is possible to reveal the internal composition, architecture, and dynamics of molecular machines and large cellular complexes. SMLM remains technically challenging, and frequently its implementation requires tailored experimental conditions that depend on the complexity of the subcellular structure of interest. Here, we describe two simple, robust, and high-throughput protocols to study molecular motors and machineries responsible for chromosome transport and organization in bacteria using 2D- and 3D-SMLM.
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Affiliation(s)
- Diego I Cattoni
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier, Montpellier, France
| | - Jean-Bernard Fiche
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier, Montpellier, France
| | - Antoine Le Gall
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier, Montpellier, France
| | - Marcelo Nollmann
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier, Montpellier, France.
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17
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Yuan X, Couto JM, Glidle A, Song Y, Sloan W, Yin H. Single-Cell Microfluidics to Study the Effects of Genome Deletion on Bacterial Growth Behavior. ACS Synth Biol 2017; 6:2219-2227. [PMID: 28844132 DOI: 10.1021/acssynbio.7b00177] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
By directly monitoring single cell growth in a microfluidic platform, we interrogated genome-deletion effects in Escherichia coli strains. We compared the growth dynamics of a wild type strain with a clean genome strain, and their derived mutants at the single-cell level. A decreased average growth rate and extended average lag time were found for the clean genome strain, compared to those of the wild type strain. Direct correlation between the growth rate and lag time of individual cells showed that the clean genome population was more heterogeneous. Cell culturability (the ratio of growing cells to the sum of growing and nongrowing cells) of the clean genome population was also lower. Interestingly, after the random mutations induced by a glucose starvation treatment, for the clean genome population mutants that had survived the competition of chemostat culture, each parameter markedly improved (i.e., the average growth rate and cell culturability increased, and the lag time and heterogeneity decreased). However, this effect was not seen in the wild type strain; the wild type mutants cultured in a chemostat retained a high diversity of growth phenotypes. These results suggest that quasi-essential genes that were deleted in the clean genome might be required to retain a diversity of growth characteristics at the individual cell level under environmental stress. These observations highlight that single-cell microfluidics can reveal subtle individual cellular responses, enabling in-depth understanding of the population.
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Affiliation(s)
- Xiaofei Yuan
- College
of Science and Engineering, Division of Biomedical Engineering, School
of Engineering, University of Glasgow, Glasgow G12 8QQ, U.K
| | - Jillian M. Couto
- College
of Science and Engineering, Division of Infrastructure and Environment,
School of Engineering, University of Glasgow, Glasgow G12 8QQ, U.K
| | - Andrew Glidle
- College
of Science and Engineering, Division of Biomedical Engineering, School
of Engineering, University of Glasgow, Glasgow G12 8QQ, U.K
| | - Yanqing Song
- College
of Science and Engineering, Division of Biomedical Engineering, School
of Engineering, University of Glasgow, Glasgow G12 8QQ, U.K
| | - William Sloan
- College
of Science and Engineering, Division of Infrastructure and Environment,
School of Engineering, University of Glasgow, Glasgow G12 8QQ, U.K
| | - Huabing Yin
- College
of Science and Engineering, Division of Biomedical Engineering, School
of Engineering, University of Glasgow, Glasgow G12 8QQ, U.K
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18
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Cattoni DI, Cardozo Gizzi AM, Georgieva M, Di Stefano M, Valeri A, Chamousset D, Houbron C, Déjardin S, Fiche JB, González I, Chang JM, Sexton T, Marti-Renom MA, Bantignies F, Cavalli G, Nollmann M. Single-cell absolute contact probability detection reveals chromosomes are organized by multiple low-frequency yet specific interactions. Nat Commun 2017; 8:1753. [PMID: 29170434 PMCID: PMC5700980 DOI: 10.1038/s41467-017-01962-x] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 10/29/2017] [Indexed: 11/09/2022] Open
Abstract
At the kilo- to megabase pair scales, eukaryotic genomes are partitioned into self-interacting modules or topologically associated domains (TADs) that associate to form nuclear compartments. Here, we combine high-content super-resolution microscopies with state-of-the-art DNA-labeling methods to reveal the variability in the multiscale organization of the Drosophila genome. We find that association frequencies within TADs and between TAD borders are below ~10%, independently of TAD size, epigenetic state, or cell type. Critically, despite this large heterogeneity, we are able to visualize nanometer-sized epigenetic domains at the single-cell level. In addition, absolute contact frequencies within and between TADs are to a large extent defined by genomic distance, higher-order chromosome architecture, and epigenetic identity. We propose that TADs and compartments are organized by multiple, small-frequency, yet specific interactions that are regulated by epigenetics and transcriptional state.
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Affiliation(s)
- Diego I Cattoni
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier, 29 rue de Navacelles, 34090, Montpellier, France
| | - Andrés M Cardozo Gizzi
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier, 29 rue de Navacelles, 34090, Montpellier, France
| | - Mariya Georgieva
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier, 29 rue de Navacelles, 34090, Montpellier, France
| | - Marco Di Stefano
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, 08028, Barcelona, Spain
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, 08010, Spain
- ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain
| | - Alessandro Valeri
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier, 29 rue de Navacelles, 34090, Montpellier, France
| | - Delphine Chamousset
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier, 29 rue de Navacelles, 34090, Montpellier, France
| | - Christophe Houbron
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier, 29 rue de Navacelles, 34090, Montpellier, France
| | - Stephanie Déjardin
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier, 29 rue de Navacelles, 34090, Montpellier, France
- Institut de Génétique Humaine, CNRS UMR 9002, Université de Montpellier, 141 rue de la Cardonille, 34396, Montpellier, France
| | - Jean-Bernard Fiche
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier, 29 rue de Navacelles, 34090, Montpellier, France
| | - Inma González
- Institut de Génétique Humaine, CNRS UMR 9002, Université de Montpellier, 141 rue de la Cardonille, 34396, Montpellier, France
- Epigenetics of Stem Cells, Department of Stem Cell and Developmental Biology, Institut Pasteur, CNRS UMR3738, 25 rue du Docteur Roux, 75015, Paris, France
| | - Jia-Ming Chang
- Institut de Génétique Humaine, CNRS UMR 9002, Université de Montpellier, 141 rue de la Cardonille, 34396, Montpellier, France
- Department of Computer Science, National Chengchi University, 11605, Taipei City, Taiwan
| | - Thomas Sexton
- Institut de Génétique Humaine, CNRS UMR 9002, Université de Montpellier, 141 rue de la Cardonille, 34396, Montpellier, France
- Institut de génétique et de biologie moléculaire et cellulaire, CNRS UMR 7104 - Inserm U 964, 67404, Illkirch, France
| | - Marc A Marti-Renom
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, 08028, Barcelona, Spain
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, 08010, Spain
- ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain
| | - Frédéric Bantignies
- Institut de Génétique Humaine, CNRS UMR 9002, Université de Montpellier, 141 rue de la Cardonille, 34396, Montpellier, France
| | - Giacomo Cavalli
- Institut de Génétique Humaine, CNRS UMR 9002, Université de Montpellier, 141 rue de la Cardonille, 34396, Montpellier, France
| | - Marcelo Nollmann
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier, 29 rue de Navacelles, 34090, Montpellier, France.
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19
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Angular reconstitution-based 3D reconstructions of nanomolecular structures from superresolution light-microscopy images. Proc Natl Acad Sci U S A 2017; 114:9273-9278. [PMID: 28811371 DOI: 10.1073/pnas.1704908114] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Superresolution light microscopy allows the imaging of labeled supramolecular assemblies at a resolution surpassing the classical diffraction limit. A serious limitation of the superresolution approach is sample heterogeneity and the stochastic character of the labeling procedure. To increase the reproducibility and the resolution of the superresolution results, we apply multivariate statistical analysis methods and 3D reconstruction approaches originally developed for cryogenic electron microscopy of single particles. These methods allow for the reference-free 3D reconstruction of nanomolecular structures from two-dimensional superresolution projection images. Since these 2D projection images all show the structure in high-resolution directions of the optical microscope, the resulting 3D reconstructions have the best possible isotropic resolution in all directions.
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20
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Kobayashi S, Iwamoto M, Haraguchi T. Live correlative light-electron microscopy to observe molecular dynamics in high resolution. Microscopy (Oxf) 2016; 65:296-308. [DOI: 10.1093/jmicro/dfw024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/01/2016] [Indexed: 12/19/2022] Open
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21
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Chin LK, Lee CH, Chen BC. Imaging live cells at high spatiotemporal resolution for lab-on-a-chip applications. LAB ON A CHIP 2016; 16:2014-24. [PMID: 27121367 DOI: 10.1039/c5lc01556a] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Conventional optical imaging techniques are limited by the diffraction limit and difficult-to-image biomolecular and sub-cellular processes in living specimens. Novel optical imaging techniques are constantly evolving with the desire to innovate an imaging tool that is capable of seeing sub-cellular processes in a biological system, especially in three dimensions (3D) over time, i.e. 4D imaging. For fluorescence imaging on live cells, the trade-offs among imaging depth, spatial resolution, temporal resolution and photo-damage are constrained based on the limited photons of the emitters. The fundamental solution to solve this dilemma is to enlarge the photon bank such as the development of photostable and bright fluorophores, leading to the innovation in optical imaging techniques such as super-resolution microscopy and light sheet microscopy. With the synergy of microfluidic technology that is capable of manipulating biological cells and controlling their microenvironments to mimic in vivo physiological environments, studies of sub-cellular processes in various biological systems can be simplified and investigated systematically. In this review, we provide an overview of current state-of-the-art super-resolution and 3D live cell imaging techniques and their lab-on-a-chip applications, and finally discuss future research trends in new and breakthrough research areas of live specimen 4D imaging in controlled 3D microenvironments.
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Affiliation(s)
- Lip Ket Chin
- School of Electrical and Electronic Engineering, Nanyang Technological University, 639798, Singapore
| | - Chau-Hwang Lee
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan. and Institute of Biophotonics, National Yang-Ming University, Taipei 11221, Taiwan and Department of Physics, National Taiwan University, Taipei 10671, Taiwan
| | - Bi-Chang Chen
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan.
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22
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23
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Mazouchi A, Milstein JN. Fast Optimized Cluster Algorithm for Localizations (FOCAL): a spatial cluster analysis for super-resolved microscopy. Bioinformatics 2015; 32:747-54. [PMID: 26543172 DOI: 10.1093/bioinformatics/btv630] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 10/24/2015] [Indexed: 11/13/2022] Open
Abstract
MOTIVATION Single-molecule localization microscopy (SMLM) microscopy provides images of cellular structure at a resolution an order of magnitude below what can be achieved by conventional diffraction limited techniques. The concomitantly larger data sets generated by SMLM require increasingly efficient image analysis software. Density based clustering algorithms, with the most ubiquitous being DBSCAN, are commonly used to quantitatively assess sub-cellular assemblies. DBSCAN, however, is slow, scaling with the number of localizations like O(n log (n)) at best, and it's performance is highly dependent upon a subjectively selected choice of parameters. RESULTS We have developed a grid-based clustering algorithm FOCAL, which explicitly accounts for several dominant artifacts arising in SMLM image reconstructions. FOCAL is fast and efficient, scaling like O(n), and only has one set parameter. We assess DBSCAN and FOCAL on experimental dSTORM data of clusters of eukaryotic RNAP II and PALM data of the bacterial protein H-NS, then provide a detailed comparison via simulation. FOCAL performs comparable and often superior to DBSCAN while yielding a significantly faster analysis. Additionally, FOCAL provides a novel method for filtering out of focus clusters from complex SMLM images. AVAILABILITY AND IMPLEMENTATION The data and code are available at: http://www.utm.utoronto.ca/milsteinlab/resources/Software/FOCAL/ CONTACT: josh.milstein@utoronto.ca SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- A Mazouchi
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - J N Milstein
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada Department of Physics, University of Toronto, Toronto, ON M5S 1A7, Canada
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24
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Marbouty M, Le Gall A, Cattoni D, Cournac A, Koh A, Fiche JB, Mozziconacci J, Murray H, Koszul R, Nollmann M. Condensin- and Replication-Mediated Bacterial Chromosome Folding and Origin Condensation Revealed by Hi-C and Super-resolution Imaging. Mol Cell 2015; 59:588-602. [DOI: 10.1016/j.molcel.2015.07.020] [Citation(s) in RCA: 205] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 06/10/2015] [Accepted: 07/21/2015] [Indexed: 12/01/2022]
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25
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Sanchez A, Cattoni D, Walter JC, Rech J, Parmeggiani A, Nollmann M, Bouet JY. Stochastic Self-Assembly of ParB Proteins Builds the Bacterial DNA Segregation Apparatus. Cell Syst 2015; 1:163-73. [DOI: 10.1016/j.cels.2015.07.013] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 06/15/2015] [Accepted: 07/30/2015] [Indexed: 11/25/2022]
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26
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Gocheva V, Le Gall A, Boudvillain M, Margeat E, Nollmann M. Direct observation of the translocation mechanism of transcription termination factor Rho. Nucleic Acids Res 2015; 43:2367-77. [PMID: 25662222 PMCID: PMC4344519 DOI: 10.1093/nar/gkv085] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Rho is a ring-shaped, ATP-fueled motor essential for remodeling transcriptional complexes and R-loops in bacteria. Despite years of research on this fundamental model helicase, key aspects of its mechanism of translocation remain largely unknown. Here, we used single-molecule manipulation and fluorescence methods to directly monitor the dynamics of RNA translocation by Rho. We show that the efficiency of Rho activation is strongly dependent on the force applied on the RNA but that, once active, Rho is able to translocate against a large opposing force (at least 7 pN) by a mechanism involving ‘tethered tracking’. Importantly, the ability to directly measure dynamics at the single-molecule level allowed us to determine essential motor properties of Rho. Hence, Rho translocates at a rate of ∼56 nt per second under our experimental conditions, which is 2–5 times faster than velocities measured for RNA polymerase under similar conditions. Moreover, the processivity of Rho (∼62 nt at a 7 pN opposing force) is large enough for Rho to reach termination sites without dissociating from its RNA loading site, potentially increasing the efficiency of transcription termination. Our findings unambiguously establish ‘tethered tracking’ as the main pathway for Rho translocation, support ‘kinetic coupling’ between Rho and RNA polymerase during Rho-dependent termination, and suggest that forces applied on the nascent RNA transcript by cellular substructures could have important implications for the regulation of transcription and its coupling to translation in vivo.
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Affiliation(s)
- Veronika Gocheva
- CNRS UMR5048, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090 Montpellier, France INSERM U554, 34090 Montpellier, France Universités Montpellier 1 et 2, 34090 Montpellier, France
| | - Antoine Le Gall
- CNRS UMR5048, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090 Montpellier, France INSERM U554, 34090 Montpellier, France Universités Montpellier 1 et 2, 34090 Montpellier, France
| | - Marc Boudvillain
- CNRS, Centre de Biophysique Moléculaire, rue Charles Sadron, 45071 Orléans, France ITP Sciences Biologiques & Chimie du Vivant, Université d'Orléans, France
| | - Emmanuel Margeat
- CNRS UMR5048, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090 Montpellier, France INSERM U554, 34090 Montpellier, France Universités Montpellier 1 et 2, 34090 Montpellier, France
| | - Marcelo Nollmann
- CNRS UMR5048, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090 Montpellier, France INSERM U554, 34090 Montpellier, France Universités Montpellier 1 et 2, 34090 Montpellier, France
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27
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Dilipkumar S, Manjithaya R, Mondal PP. Multispectral Bayesian reconstruction technique for real-time two color fluorescence microscopy. RSC Adv 2015. [DOI: 10.1039/c4ra15225e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We have developed a real-time imaging method for two-color widefield fluorescence microscopy using a combined approach that integrates multi-spectral imaging and Bayesian image reconstruction technique.
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Affiliation(s)
- Shilpa Dilipkumar
- Nanobioimaging Laboratory
- Department of Instrumentation and Applied Physics
- Indian Institute of Science
- Bangalore 560012
- India
| | - Ravi Manjithaya
- Molecular Biology and Genetics Unit
- Jawaharlal Nehru Center for Advanced Scientific Research
- Bangalore 560064
- India
| | - Partha Pratim Mondal
- Nanobioimaging Laboratory
- Department of Instrumentation and Applied Physics
- Indian Institute of Science
- Bangalore 560012
- India
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28
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Constructing a magnetic tweezers to monitor RNA translocation at the single-molecule level. Methods Mol Biol 2015; 1259:257-73. [PMID: 25579591 DOI: 10.1007/978-1-4939-2214-7_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Single-molecule methods have become an invaluable tool in the investigation of the mechanisms of nucleic-acid motors. Magnetic tweezers is a single-molecule manipulation technique that permits the real-time measurement of enzyme activities on single nucleic-acid molecules at high-resolution, high-throughput, and inherently constant force. Here, we describe several aspects of the implementation of magnetic tweezers, with special emphasis on the construction of a simple magnetic trap and, in particular, on the detailed description of image analysis methods to measure the extension changes in nucleic-acid molecules induced by protein activity. Finally, we carefully describe the steps involved in performing a full magnetic tweezers experiment.
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29
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Tam J, Cordier GA, Bálint Š, Sandoval Álvarez Á, Borbely JS, Lakadamyali M. A microfluidic platform for correlative live-cell and super-resolution microscopy. PLoS One 2014; 9:e115512. [PMID: 25545548 PMCID: PMC4278722 DOI: 10.1371/journal.pone.0115512] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 11/24/2014] [Indexed: 11/18/2022] Open
Abstract
Recently, super-resolution microscopy methods such as stochastic optical reconstruction microscopy (STORM) have enabled visualization of subcellular structures below the optical resolution limit. Due to the poor temporal resolution, however, these methods have mostly been used to image fixed cells or dynamic processes that evolve on slow time-scales. In particular, fast dynamic processes and their relationship to the underlying ultrastructure or nanoscale protein organization cannot be discerned. To overcome this limitation, we have recently developed a correlative and sequential imaging method that combines live-cell and super-resolution microscopy. This approach adds dynamic background to ultrastructural images providing a new dimension to the interpretation of super-resolution data. However, currently, it suffers from the need to carry out tedious steps of sample preparation manually. To alleviate this problem, we implemented a simple and versatile microfluidic platform that streamlines the sample preparation steps in between live-cell and super-resolution imaging. The platform is based on a microfluidic chip with parallel, miniaturized imaging chambers and an automated fluid-injection device, which delivers a precise amount of a specified reagent to the selected imaging chamber at a specific time within the experiment. We demonstrate that this system can be used for live-cell imaging, automated fixation, and immunostaining of adherent mammalian cells in situ followed by STORM imaging. We further demonstrate an application by correlating mitochondrial dynamics, morphology, and nanoscale mitochondrial protein distribution in live and super-resolution images.
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Affiliation(s)
- Johnny Tam
- ICFO-Institut de Ciències Fotòniques (ICFO), 08860, Castelledefels (Barcelona), Spain
| | | | - Štefan Bálint
- ICFO-Institut de Ciències Fotòniques (ICFO), 08860, Castelledefels (Barcelona), Spain
| | | | - Joseph Steven Borbely
- ICFO-Institut de Ciències Fotòniques (ICFO), 08860, Castelledefels (Barcelona), Spain
| | - Melike Lakadamyali
- ICFO-Institut de Ciències Fotòniques (ICFO), 08860, Castelledefels (Barcelona), Spain
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