1
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Blum D, Reuter M, Schliebs W, Tomaschewski J, Erdmann R, Wagner R. Membrane binding and pore forming insertion of PEX5 into horizontal lipid bilayer. Biol Chem 2023; 404:157-167. [PMID: 36260915 DOI: 10.1515/hsz-2022-0183] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/29/2022] [Indexed: 11/15/2022]
Abstract
The assembly of the peroxisomal translocon involves the transition of a soluble form of the peroxisomal targeting receptor PEX5 into a membrane-bound form, which becomes an integral membrane component of the import pore for peroxisomal matrix proteins. How this transition occurs is still a mystery. We addressed this question using a artificial horizontal bilayer in combination with fluorescence time-correlated single photon counting (TCSPC) and electrophysiological channel recording. Purified human isoform PEX5L and truncated PEX5L(1-335) lacking the cargo binding domain were selectively labeled with thiol-reactive Atto-dyes. Diffusion coefficients of labeled protein in solution show that PEX5L is monomeric with a rather compact spherical conformation, while the truncated protein appeared in a more extended conformation. Labeled PEX5L and the truncated PEX5L(1-335) bind stably to horizontal bilayer thereby accumulating around 100-fold. The diffusion coefficients of the membrane-bound PEX5L forms are 3-4 times lower than in solution, indicating the formation of larger complexes. Electrophysiological single channel recording shows that membrane-bound labeled and non-labeled PEX5L, but not the truncated PEX5L(1-335), can form ion conducting membrane channels. The data suggest that PEX5L is the pore-forming component of the oligomeric peroxisomal translocon and that spontaneous PEX5L membrane surface binding might be an important step in its assembly.
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Affiliation(s)
- Daniel Blum
- MOLIFE Research Center, Jacobs, University Bremen, D-28759 Bremen, Germany
| | - Maren Reuter
- Institut für Biochemie und Pathobiochemie, Abt. Systembiochemie, Medizinische Fakultät, Ruhr-Universität Bochum, D-44801 Bochum, Germany
| | - Wolfgang Schliebs
- Institut für Biochemie und Pathobiochemie, Abt. Systembiochemie, Medizinische Fakultät, Ruhr-Universität Bochum, D-44801 Bochum, Germany
| | - Jana Tomaschewski
- Institut für Biochemie und Pathobiochemie, Abt. Systembiochemie, Medizinische Fakultät, Ruhr-Universität Bochum, D-44801 Bochum, Germany
| | - Ralf Erdmann
- Institut für Biochemie und Pathobiochemie, Abt. Systembiochemie, Medizinische Fakultät, Ruhr-Universität Bochum, D-44801 Bochum, Germany
| | - Richard Wagner
- MOLIFE Research Center, Jacobs, University Bremen, D-28759 Bremen, Germany
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2
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Liput DJ, Nguyen TA, Augustin SM, Lee JO, Vogel SS. A Guide to Fluorescence Lifetime Microscopy and Förster's Resonance Energy Transfer in Neuroscience. CURRENT PROTOCOLS IN NEUROSCIENCE 2020; 94:e108. [PMID: 33232577 PMCID: PMC8274369 DOI: 10.1002/cpns.108] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Fluorescence lifetime microscopy (FLIM) and Förster's resonance energy transfer (FRET) are advanced optical tools that neuroscientists can employ to interrogate the structure and function of complex biological systems in vitro and in vivo using light. In neurobiology they are primarily used to study protein-protein interactions, to study conformational changes in protein complexes, and to monitor genetically encoded FRET-based biosensors. These methods are ideally suited to optically monitor changes in neurons that are triggered optogenetically. Utilization of this technique by neuroscientists has been limited, since a broad understanding of FLIM and FRET requires familiarity with the interactions of light and matter on a quantum mechanical level, and because the ultra-fast instrumentation used to measure fluorescent lifetimes and resonance energy transfer are more at home in a physics lab than in a biology lab. In this overview, we aim to help neuroscientists overcome these obstacles and thus feel more comfortable with the FLIM-FRET method. Our goal is to aid researchers in the neuroscience community to achieve a better understanding of the fundamentals of FLIM-FRET and encourage them to fully leverage its powerful ability as a research tool. Published 2020. U.S. Government.
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Affiliation(s)
- Daniel J. Liput
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
- Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
| | - Tuan A. Nguyen
- Laboratory of Biophotonics and Quantum Biology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
| | - Shana M. Augustin
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
| | - Jeong Oen Lee
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
| | - Steven S. Vogel
- Laboratory of Biophotonics and Quantum Biology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
- Corresponding author:
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3
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Ranjit S, Datta R, Dvornikov A, Gratton E. Multicomponent Analysis of Phasor Plot in a Single Pixel to Calculate Changes of Metabolic Trajectory in Biological Systems. J Phys Chem A 2019; 123:9865-9873. [PMID: 31638388 DOI: 10.1021/acs.jpca.9b07880] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Phasor FLIM in cells undergoing oxidative stress and in mice liver sections have shown the presence of a third autofluorescent component indicative of lipid droplets along with free and enzyme-bound NADH with similar emissions. This third component affects the position and shape of the phasor distribution, pushing it away from the metabolic trajectory. Phasor rule of addition is still valid and was exploited here to create a multicomponent analysis where the phasor distribution can be reassigned to the metabolic trajectory and changes in metabolism can be detected independently of the intensity of this third component. Calculation of multiple components from FLIM imaging data of biological systems is a difficult process, especially if different fluorescent species are present at the same pixel. This paper describes the methodology that can be used to separate these multiple components when they are present in the phasor signature acquired in a single pixel of an image.
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Affiliation(s)
- Suman Ranjit
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering , University of California , Irvine , California 92697 , United States.,Department of Biochemistry and Molecular & Cellular Biology , Georgetown University , Washington , D.C. 20057 , United States
| | - Rupsa Datta
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering , University of California , Irvine , California 92697 , United States.,Morgridge Institute for Research , 330 North Orchard Street , Madison , Wisconsin 53715 , United States
| | - Alexander Dvornikov
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering , University of California , Irvine , California 92697 , United States
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering , University of California , Irvine , California 92697 , United States
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4
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Maibohm C, Silva F, Figueiras E, Guerreiro PT, Brito M, Romero R, Crespo H, Nieder JB. SyncRGB-FLIM: synchronous fluorescence imaging of red, green and blue dyes enabled by ultra-broadband few-cycle laser excitation and fluorescence lifetime detection. BIOMEDICAL OPTICS EXPRESS 2019; 10:1891-1904. [PMID: 31086710 PMCID: PMC6484984 DOI: 10.1364/boe.10.001891] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 02/01/2019] [Accepted: 02/06/2019] [Indexed: 06/09/2023]
Abstract
We demonstrate for the first time that an ultra-broadband 7 femtosecond (fs) few-cycle laser can be used for multicolor nonlinear imaging in a single channel detection geometry, when employing a time-resolved fluorescence detection scheme. On a multi-chromophore-labelled cell sample we show that the few-cycle laser can efficiently excite the multiple chromophores over a >400 nm two-photon absorption range. By combining the few-cycle laser excitation with time-correlated single-photon counting (TCSPC) detection to record two-photon fluorescence lifetime imaging microscopy (FLIM) images, the localization of different chromophores in the cell can be identified based on their fluorescence decay properties. The novel SyncRGB-FLIM multi-color bioimaging technique opens the possibility of real-time protein-protein interaction studies, where its single-scan operation translates into reduced laser exposure of the sample, resulting in more photoprotective conditions for biological specimens.
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Affiliation(s)
- Christian Maibohm
- Department of Nanophotonics, Ultrafast Bio- and Nanophotonics Group, INL-International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga n/a, 4715-330 Braga, Portugal
| | - Francisco Silva
- Sphere Ultrafast Photonics, R. do Campo Alegre 1021, Edifício FC6, 4169-007 Porto, Portugal
| | - Edite Figueiras
- Department of Nanophotonics, Ultrafast Bio- and Nanophotonics Group, INL-International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga n/a, 4715-330 Braga, Portugal
- Present address: Fundação Champalimaud, Avenida Brasília, 1400-038 Lisboa, Portugal
| | - Paulo T. Guerreiro
- Sphere Ultrafast Photonics, R. do Campo Alegre 1021, Edifício FC6, 4169-007 Porto, Portugal
- IFIMUP-IN and Dept. of Physics and Astronomy, Faculty of Sciences, University Porto, R. do Campo Alegre 697, 4169-007 Porto, Portugal
| | - Marina Brito
- Department of Nanophotonics, Ultrafast Bio- and Nanophotonics Group, INL-International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga n/a, 4715-330 Braga, Portugal
| | - Rosa Romero
- Sphere Ultrafast Photonics, R. do Campo Alegre 1021, Edifício FC6, 4169-007 Porto, Portugal
- IFIMUP-IN and Dept. of Physics and Astronomy, Faculty of Sciences, University Porto, R. do Campo Alegre 697, 4169-007 Porto, Portugal
| | - Helder Crespo
- Sphere Ultrafast Photonics, R. do Campo Alegre 1021, Edifício FC6, 4169-007 Porto, Portugal
- IFIMUP-IN and Dept. of Physics and Astronomy, Faculty of Sciences, University Porto, R. do Campo Alegre 697, 4169-007 Porto, Portugal
| | - Jana B. Nieder
- Department of Nanophotonics, Ultrafast Bio- and Nanophotonics Group, INL-International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga n/a, 4715-330 Braga, Portugal
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5
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Sharma KK, Marzinek JK, Tantirimudalige SN, Bond PJ, Wohland T. Single-molecule studies of flavivirus envelope dynamics: Experiment and computation. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 143:38-51. [PMID: 30223001 DOI: 10.1016/j.pbiomolbio.2018.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/06/2018] [Accepted: 09/11/2018] [Indexed: 12/11/2022]
Abstract
Flaviviruses are simple enveloped viruses exhibiting complex structural and functional heterogeneities. Decades of research have provided crucial basic insights, antiviral medication and moderately successful gene therapy trials. The most infectious particle is, however, not always the most abundant one in a population, questioning the utility of classic ensemble-averaging virology approaches. Indeed, viral replication is often not particularly efficient, prone to errors or containing parallel routes. Here, we review different single-molecule sensitive fluorescence methods that are employed to investigate flaviviruses. In particular, we review how (i) time-resolved Förster resonance energy transfer (trFRET) was applied to probe dengue envelope conformations; (ii) FRET-fluorescence correlation spectroscopy to investigate dengue envelope intrinsic dynamics and (iii) single particle tracking to follow the path of dengue viruses in cells. We also discuss how such methods may be supported by molecular dynamics (MD) simulations over a range of spatio-temporal scales, to provide complementary data on the structure and dynamics of flaviviral systems. We describe recent improvements in multiscale MD approaches that allowed the simulation of dengue particle envelopes in near-atomic resolution. We hope this review is an incentive for setting up and applying similar single-molecule studies and combine them with MD simulations to investigate structural dynamics of entire flavivirus particles over the nanosecond-to-millisecond time-scale and follow viruses during infection in cells over milliseconds to minutes.
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Affiliation(s)
- Kamal Kant Sharma
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Jan K Marzinek
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore; Bioinformatics Institute (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore
| | - Sarala Neomi Tantirimudalige
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Peter J Bond
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore; Bioinformatics Institute (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore.
| | - Thorsten Wohland
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore; Department of Chemistry, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore; Centre for Bioimaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117557, Singapore.
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6
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Ranjit S, Malacrida L, Gratton E. Differences between FLIM phasor analyses for data collected with the Becker and Hickl SPC830 card and with the FLIMbox card. Microsc Res Tech 2018; 81:980-989. [PMID: 30295346 PMCID: PMC6240382 DOI: 10.1002/jemt.23061] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 05/13/2018] [Indexed: 01/31/2023]
Abstract
The phasor approach to FLIM (Fluorescence Lifetime Imaging Microscopy) is becoming popular due to the powerful fit free analysis and the visualization of the decay at each point in images of cells and tissues. However, although several implementation of the method are offered by manufactures of FLIM accessories for microscopes, the details of the conversion of the decay to phasors at each point in an image requires some consideration. Here, we show that if the decay is not properly acquired, the apparently simple phasor transformation can provide incorrect phasor plots and the results may be misinterpreted. In particular, we show the disagreement in experimental data acquired on the same samples using the two cards (FLIMbox, frequency domain and Becker & Hickl BH 830, time domain) and the effect produced by using the BH 830 card with different settings. This difference in data acquisition translates to the assignment of phasor components calculated using different acquisition parameters. This effect is already present in the original data that are not acquired with the proper parameters for the phasor conversion. We also show that the difference in the resolution of components already exists in the data acquired in the time domain when used with settings that do not allow acquisition of the fluorescence decay on a sufficient large time scale. RESEARCH HIGHLIGHTS: This paper is intended to made researchers aware of some simple requirements for the conversion of time-domain data (typically TCSPC) to phasors. The use of phasors for FLIM analysis has seen a surge of popularity. Since the phasor approach is a fit free method and has a powerful visualization of the data, it appears very simple to use. This paper shows that when the original data in the time domain is not acquired with the proper time range to cover the lifetimes in a sample, the conversion to phasors can produce very erroneous results. These results are appearing more frequently in the literature since many of the manufacturers of FLIM accessories for microscopes are now offering the phasor analysis in their software. Here, we show that the phasor transformation per se cannot correct for the problems with data acquisition and that one is misled to think that the "phasor approach" is a universal fix for the lack of the proper time range for data acquisition.
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Affiliation(s)
- Suman Ranjit
- Laboratory for Fluorescence Dynamics, University of California, Irvine, Irvine, California
| | - Leonel Malacrida
- Laboratory for Fluorescence Dynamics, University of California, Irvine, Irvine, California
- Departamento de Fisiopatología, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, University of California, Irvine, Irvine, California
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7
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Warren SC, Nobis M, Magenau A, Mohammed YH, Herrmann D, Moran I, Vennin C, Conway JR, Mélénec P, Cox TR, Wang Y, Morton JP, Welch HC, Strathdee D, Anderson KI, Phan TG, Roberts MS, Timpson P. Removing physiological motion from intravital and clinical functional imaging data. eLife 2018; 7:35800. [PMID: 29985127 PMCID: PMC6037484 DOI: 10.7554/elife.35800] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 06/08/2018] [Indexed: 12/27/2022] Open
Abstract
Intravital microscopy can provide unique insights into the function of biological processes in a native context. However, physiological motion caused by peristalsis, respiration and the heartbeat can present a significant challenge, particularly for functional readouts such as fluorescence lifetime imaging (FLIM), which require longer acquisition times to obtain a quantitative readout. Here, we present and benchmark Galene, a versatile multi-platform software tool for image-based correction of sample motion blurring in both time resolved and conventional laser scanning fluorescence microscopy data in two and three dimensions. We show that Galene is able to resolve intravital FLIM-FRET images of intra-abdominal organs in murine models and NADH autofluorescence of human dermal tissue imaging subject to a wide range of physiological motions. Thus, Galene can enable FLIM imaging in situations where a stable imaging platform is not always possible and rescue previously discarded quantitative imaging data. Understanding how molecules and cells behave in living animals can give researchers key insights into what goes wrong in diseases such as cancer, and how well potential treatments for these diseases work. A number of tools help us to see these processes. For example, fluorescent ‘biosensors’ change colour to tell us how active a particular protein is. This can indicate how well a drug works in different parts of a tumour. High resolution microscopy makes it possible to image events happening in single cells, or even specific parts of a cell. However, small movements like those due to the heartbeat or breathing can blur the images, making it difficult to study living animals. This is particularly problematic for images that take several minutes to capture. Warren et al. have now developed a new open source software tool called Galene. The tool can correct for small movements in images collected by a technique called fluorescence lifetime imaging microscopy (FLIM). As a result, clear images can be captured in situations that were not previously possible. For example, Warren et al. watched cancer cells migrating to the liver of a mouse from the spleen over 24 hours, and, using a fluorescent biosensor, showed that a repurposed drug interferes with how well the cells can attach to the liver. In addition, Warren et al. used the software to take steady 3D images of human skin in a volunteer’s arm, which could be used to study drug penetration. Galene could help researchers to study a wide range of biological processes in living animals. The software can also be applied to existing data to clean up blurred images. In the future Galene could be further developed to work with the imaging techniques used during surgery. For example, surgeons could use it to help them find the edges of tumours.
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Affiliation(s)
- Sean C Warren
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, University of New South Wales, Sydney, Australia.,St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Max Nobis
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, University of New South Wales, Sydney, Australia.,St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Astrid Magenau
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, University of New South Wales, Sydney, Australia.,St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Yousuf H Mohammed
- Therapeutics Research Centre, Diamantina Institute, Faculty of Medicine, University of Queensland, Woolloongabba, Australia
| | - David Herrmann
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, University of New South Wales, Sydney, Australia.,St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Imogen Moran
- St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia.,Immunology Division, Garvan Institute of Medical Research, Sydney, Australia
| | - Claire Vennin
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, University of New South Wales, Sydney, Australia.,St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - James Rw Conway
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, University of New South Wales, Sydney, Australia.,St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Pauline Mélénec
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, University of New South Wales, Sydney, Australia
| | - Thomas R Cox
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, University of New South Wales, Sydney, Australia.,St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Yingxiao Wang
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, San Diego, United States
| | | | - Heidi Ce Welch
- Signalling Programme, Babraham Institute, Cambridge, United Kingdom
| | | | - Kurt I Anderson
- Cancer Research UK Beatson Institute, Glasgow, United Kingdom.,Francis Crick Institute, London, United Kingdom
| | - Tri Giang Phan
- St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia.,Immunology Division, Garvan Institute of Medical Research, Sydney, Australia
| | - Michael S Roberts
- Therapeutics Research Centre, Diamantina Institute, Faculty of Medicine, University of Queensland, Woolloongabba, Australia.,Therapeutics Research Centre, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia
| | - Paul Timpson
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, University of New South Wales, Sydney, Australia.,St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia
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8
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Niehörster T, Löschberger A, Gregor I, Krämer B, Rahn HJ, Patting M, Koberling F, Enderlein J, Sauer M. Multi-target spectrally resolved fluorescence lifetime imaging microscopy. Nat Methods 2016; 13:257-62. [PMID: 26808668 DOI: 10.1038/nmeth.3740] [Citation(s) in RCA: 134] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/16/2015] [Indexed: 01/09/2023]
Abstract
We introduce a pattern-matching technique for efficient identification of fluorophore ratios in complex multidimensional fluorescence signals using reference fluorescence decay and spectral signature patterns of individual fluorescent probes. Alternating pulsed laser excitation at three different wavelengths and time-resolved detection on 32 spectrally separated detection channels ensures efficient excitation of fluorophores and a maximum gain of fluorescence information. Using spectrally resolved fluorescence lifetime imaging microscopy (sFLIM), we were able to visualize up to nine different target molecules simultaneously in mouse C2C12 cells. By exploiting the sensitivity of fluorescence emission spectra and the lifetime of organic fluorophores on environmental factors, we carried out fluorescence imaging of three different target molecules in human U2OS cells with the same fluorophore. Our results demonstrate that sFLIM can be used for super-resolution multi-target imaging by stimulated emission depletion (STED).
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Affiliation(s)
- Thomas Niehörster
- Department of Biotechnology &Biophysics, Julius Maximilian University of Würzburg, Würzburg, Germany
| | - Anna Löschberger
- Department of Biotechnology &Biophysics, Julius Maximilian University of Würzburg, Würzburg, Germany
| | - Ingo Gregor
- Drittes Physikalisches Institut, Georg-August-Universität, Göttingen, Germany
| | | | | | | | | | - Jörg Enderlein
- Drittes Physikalisches Institut, Georg-August-Universität, Göttingen, Germany
| | - Markus Sauer
- Department of Biotechnology &Biophysics, Julius Maximilian University of Würzburg, Würzburg, Germany
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Young MD, Field JJ, Sheetz KE, Bartels RA, Squier J. A pragmatic guide to multiphoton microscope design. ADVANCES IN OPTICS AND PHOTONICS 2015; 7:276-378. [PMID: 27182429 PMCID: PMC4863715 DOI: 10.1364/aop.7.000276] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Multiphoton microscopy has emerged as a ubiquitous tool for studying microscopic structure and function across a broad range of disciplines. As such, the intent of this paper is to present a comprehensive resource for the construction and performance evaluation of a multiphoton microscope that will be understandable to the broad range of scientific fields that presently exploit, or wish to begin exploiting, this powerful technology. With this in mind, we have developed a guide to aid in the design of a multiphoton microscope. We discuss source selection, optical management of dispersion, image-relay systems with scan optics, objective-lens selection, single-element light-collection theory, photon-counting detection, image rendering, and finally, an illustrated guide for building an example microscope.
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Affiliation(s)
- Michael D. Young
- Center for Microintegrated Optics for Advanced Biological Control, Department of Physics, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA
| | - Jeffrey J. Field
- W. M. Keck Laboratory for Raman Imaging of Cell-to-Cell Communications, Colorado State University, Fort Collins, Colorado 80523, USA
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Kraig E. Sheetz
- Photonics Research Center, Department of Physics and Nuclear Engineering, United States Military Academy, West Point, New York 10996, USA
| | - Randy A. Bartels
- W. M. Keck Laboratory for Raman Imaging of Cell-to-Cell Communications, Colorado State University, Fort Collins, Colorado 80523, USA
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80523, USA
- School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Jeff Squier
- Center for Microintegrated Optics for Advanced Biological Control, Department of Physics, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA
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11
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Becker W. Fluorescence lifetime imaging by multi-dimensional time correlated single photon counting. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.medpho.2015.02.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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12
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13
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Rinnenthal JL, Börnchen C, Radbruch H, Andresen V, Mossakowski A, Siffrin V, Seelemann T, Spiecker H, Moll I, Herz J, Hauser AE, Zipp F, Behne MJ, Niesner R. Parallelized TCSPC for dynamic intravital fluorescence lifetime imaging: quantifying neuronal dysfunction in neuroinflammation. PLoS One 2013; 8:e60100. [PMID: 23613717 PMCID: PMC3629055 DOI: 10.1371/journal.pone.0060100] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 02/22/2013] [Indexed: 01/27/2023] Open
Abstract
Two-photon laser-scanning microscopy has revolutionized our view on vital processes by revealing motility and interaction patterns of various cell subsets in hardly accessible organs (e.g. brain) in living animals. However, current technology is still insufficient to elucidate the mechanisms of organ dysfunction as a prerequisite for developing new therapeutic strategies, since it renders only sparse information about the molecular basis of cellular response within tissues in health and disease. In the context of imaging, Förster resonant energy transfer (FRET) is one of the most adequate tools to probe molecular mechanisms of cell function. As a calibration-free technique, fluorescence lifetime imaging (FLIM) is superior for quantifying FRET in vivo. Currently, its main limitation is the acquisition speed in the context of deep-tissue 3D and 4D imaging. Here we present a parallelized time-correlated single-photon counting point detector (p-TCSPC) (i) for dynamic single-beam scanning FLIM of large 3D areas on the range of hundreds of milliseconds relevant in the context of immune-induced pathologies as well as (ii) for ultrafast 2D FLIM in the range of tens of milliseconds, a scale relevant for cell physiology. We demonstrate its power in dynamic deep-tissue intravital imaging, as compared to multi-beam scanning time-gated FLIM suitable for fast data acquisition and compared to highly sensitive single-channel TCSPC adequate to detect low fluorescence signals. Using p-TCSPC, 256×256 pixel FLIM maps (300×300 µm(2)) are acquired within 468 ms while 131×131 pixel FLIM maps (75×75 µm(2)) can be acquired every 82 ms in 115 µm depth in the spinal cord of CerTN L15 mice. The CerTN L15 mice express a FRET-based Ca-biosensor in certain neuronal subsets. Our new technology allows us to perform time-lapse 3D intravital FLIM (4D FLIM) in the brain stem of CerTN L15 mice affected by experimental autoimmune encephalomyelitis and, thereby, to truly quantify neuronal dysfunction in neuroinflammation.
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Affiliation(s)
- Jan Leo Rinnenthal
- German Rheumatism Research Center, Berlin, Germany
- Charité – University of Medicine, Berlin, Germany
| | - Christian Börnchen
- Department of Dermatology and Venerology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Helena Radbruch
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
- Charité – University of Medicine, Berlin, Germany
| | | | - Agata Mossakowski
- German Rheumatism Research Center, Berlin, Germany
- Charité – University of Medicine, Berlin, Germany
| | - Volker Siffrin
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
- Neurology Department, Johannes Gutenberg University Mainz, Mainz, Germany
| | | | | | - Ingrid Moll
- Department of Dermatology and Venerology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Josephine Herz
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
- Charité – University of Medicine, Berlin, Germany
| | - Anja E. Hauser
- German Rheumatism Research Center, Berlin, Germany
- Charité – University of Medicine, Berlin, Germany
| | - Frauke Zipp
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
- Neurology Department, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Martin J. Behne
- Department of Dermatology and Venerology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Raluca Niesner
- German Rheumatism Research Center, Berlin, Germany
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
- Charité – University of Medicine, Berlin, Germany
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14
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Chen LC, Lloyd WR, Chang CW, Sud D, Mycek MA. Fluorescence lifetime imaging microscopy for quantitative biological imaging. Methods Cell Biol 2013; 114:457-88. [PMID: 23931519 DOI: 10.1016/b978-0-12-407761-4.00020-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Fluorescence lifetime imaging microscopy (FLIM) is a method for measuring fluorophore lifetimes with microscopic spatial resolution, providing a useful tool for cell biologists to detect, visualize, and investigate structure and function of biological systems. In this chapter, we begin by introducing the basic theory of fluorescence lifetime, including the characteristics of fluorophore decay, followed by a discussion of factors affecting fluorescence lifetimes and the potential advantages of fluorescence lifetime as a source of image contrast. Experimental methods for creating lifetime maps, including both time- and frequency-domain experimental approaches, are then introduced. Then, FLIM data analysis methods are discussed, including rapid lifetime determination, multiexponential fitting, Laguerre polynomial fitting, and phasor plot analysis. After, data analysis methods are introduced that improve lifetime precision of FLIM maps based upon optimal virtual gating and total variation denoising. The chapter concludes by highlighting several recent FLIM applications for quantitative biological imaging, including Förster resonance energy transfer-FLIM, fluorescence correlation spectroscopy-FLIM, multispectral-FLIM, and multiphoton-FLIM.
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Affiliation(s)
- Leng-Chun Chen
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
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15
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Bartsch P, Walter C, Selenschik P, Honigmann A, Wagner R. Horizontal Bilayer for Electrical and Optical Recordings. MATERIALS 2012. [PMCID: PMC5449052 DOI: 10.3390/ma5122705] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Philipp Bartsch
- Biophysics, Department of Biology/Chemistry, University Osnabrueck, Barbarastr. 13, Osnabrueck 49076, Germany; E-Mails: (P.B.); (C.W.); (P.S.); (A.H.)
- Ionovation GmbH, Westerbreite 7, Osnabrueck 49084, Germany
| | - Claudius Walter
- Biophysics, Department of Biology/Chemistry, University Osnabrueck, Barbarastr. 13, Osnabrueck 49076, Germany; E-Mails: (P.B.); (C.W.); (P.S.); (A.H.)
- Ionovation GmbH, Westerbreite 7, Osnabrueck 49084, Germany
| | - Philipp Selenschik
- Biophysics, Department of Biology/Chemistry, University Osnabrueck, Barbarastr. 13, Osnabrueck 49076, Germany; E-Mails: (P.B.); (C.W.); (P.S.); (A.H.)
| | - Alf Honigmann
- Biophysics, Department of Biology/Chemistry, University Osnabrueck, Barbarastr. 13, Osnabrueck 49076, Germany; E-Mails: (P.B.); (C.W.); (P.S.); (A.H.)
| | - Richard Wagner
- Biophysics, Department of Biology/Chemistry, University Osnabrueck, Barbarastr. 13, Osnabrueck 49076, Germany; E-Mails: (P.B.); (C.W.); (P.S.); (A.H.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +49-541-969-2398; Fax: +49-541-969-2243
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16
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Helm PJ. Proposal of a New Method for Measuring Förster Resonance Energy Transfer (FRET) Rapidly, Quantitatively and Non-Destructively. Int J Mol Sci 2012. [PMID: 23202903 PMCID: PMC3497277 DOI: 10.3390/ijms131012367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The process of radiationless energy transfer from a chromophore in an excited electronic state (the “donor”) to another chromophore (an “acceptor”), in which the energy released by the donor effects an electronic transition, is known as “Förster Resonance Energy Transfer” (FRET). The rate of energy transfer is dependent on the sixth power of the distance between donor and acceptor. Determining FRET efficiencies is tantamount to measuring distances between molecules. A new method is proposed for determining FRET efficiencies rapidly, quantitatively, and non-destructively on ensembles containing donor acceptor pairs: at wavelengths suitable for mutually exclusive excitations of donors and acceptors, two laser beams are intensity-modulated in rectangular patterns at duty cycle ½ and frequencies f1 and f2 by electro-optic modulators. In an ensemble exposed to these laser beams, the donor excitation is modulated at f1, and the acceptor excitation, and therefore the degree of saturation of the excited electronic state of the acceptors, is modulated at f2. Since the ensemble contains donor acceptor pairs engaged in FRET, the released donor fluorescence is modulated not only at f1 but also at the beat frequency Δf: = |f1 − f2|. The depth of the latter modulation, detectable via a lock-in amplifier, quantitatively indicates the FRET efficiency.
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Affiliation(s)
- Paul Johannes Helm
- Center of Molecular Biology and Neuroscience and Institute of Basic Medical Sciences, Department of Anatomy, University of Oslo, P.O. Box 1105-Blindern, NO-0317 Oslo, Norway.
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17
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Prow TW. Multiphoton microscopy applications in nanodermatology. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2012; 4:680-90. [DOI: 10.1002/wnan.1189] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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18
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19
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Chen YC, Clegg RM. Spectral resolution in conjunction with polar plots improves the accuracy and reliability of FLIM measurements and estimates of FRET efficiency. J Microsc 2011; 244:21-37. [PMID: 21801176 DOI: 10.1111/j.1365-2818.2011.03488.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A spectrograph with continuous wavelength resolution has been integrated into a frequency-domain fluorescence lifetime-resolved imaging microscope (FLIM). The spectral information assists in the separation of multiple lifetime components, and helps resolve signal cross-talking that can interfere with an accurate analysis of multiple lifetime processes. This extends the number of different dyes that can be measured simultaneously in a FLIM measurement. Spectrally resolved FLIM (spectral-FLIM) also provides a means to measure more accurately the lifetime of a dim fluorescence component (as low as 2% of the total intensity) in the presence of another fluorescence component with a much higher intensity. A more reliable separation of the donor and acceptor fluorescence signals are possible for Förster resonance energy transfer (FRET) measurements; this allows more accurate determinations of both donor and acceptor lifetimes. By combining the polar plot analysis with spectral-FLIM data, the spectral dispersion of the acceptor signal can be used to derive the donor lifetime - and thereby the FRET efficiency - without iterative fitting. The lifetime relation between the donor and acceptor, in conjunction with spectral dispersion, is also used to separate the FRET pair signals from the donor alone signal. This method can be applied further to quantify the signals from separate FRET pairs, and provide information on the dynamics of the FRET pair between different states.
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Affiliation(s)
- Y-C Chen
- Bioengineering Department, University of Illinois at Urbana-Champaign, U.S.A
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20
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Barber PR, Ameer-Beg SM, Pathmananthan S, Rowley M, Coolen ACC. A Bayesian method for single molecule, fluorescence burst analysis. BIOMEDICAL OPTICS EXPRESS 2010; 1:1148-1158. [PMID: 21258537 PMCID: PMC3018088 DOI: 10.1364/boe.1.001148] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Accepted: 10/04/2010] [Indexed: 05/18/2023]
Abstract
There is currently great interest in determining physical parameters, e.g. fluorescence lifetime, of individual molecules that inform on environmental conditions, whilst avoiding the artefacts of ensemble averaging. Protein interactions, molecular dynamics and sub-species can all be studied. In a burst integrated fluorescence lifetime (BIFL) experiment, identification of fluorescent bursts from single molecules above background detection is a problem. This paper presents a Bayesian method for burst identification based on model selection and demonstrates the detection of bursts consisting of 10% signal amplitude. The method also estimates the fluorescence lifetime (and its error) from the burst data.
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Affiliation(s)
- P. R. Barber
- University of Oxford, Gray Institute for Radiation Oncology and Biology,
Old Road Campus, Oxford OX3 7DQ, UK
- King's College London, Division of Cancer Research & Randall Division of Cell and Molecular Biophysics, Richard Dimbleby Department of Cancer Research,
Guy's Campus, London SE1 1UL, UK
| | - S. M. Ameer-Beg
- King's College London, Division of Cancer Research & Randall Division of Cell and Molecular Biophysics, Richard Dimbleby Department of Cancer Research,
Guy's Campus, London SE1 1UL, UK
| | - S. Pathmananthan
- King's College London, Division of Cancer Research & Randall Division of Cell and Molecular Biophysics, Richard Dimbleby Department of Cancer Research,
Guy's Campus, London SE1 1UL, UK
| | - M. Rowley
- King's College London, Division of Cancer Research & Randall Division of Cell and Molecular Biophysics, Richard Dimbleby Department of Cancer Research,
Guy's Campus, London SE1 1UL, UK
| | - A. C. C. Coolen
- King's College London, Division of Cancer Research & Randall Division of Cell and Molecular Biophysics, Richard Dimbleby Department of Cancer Research,
Guy's Campus, London SE1 1UL, UK
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21
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FRET characterisation for cross-bridge dynamics in single-skinned rigor muscle fibres. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2010; 40:13-27. [PMID: 20824272 PMCID: PMC3000472 DOI: 10.1007/s00249-010-0624-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 08/09/2010] [Accepted: 08/16/2010] [Indexed: 11/15/2022]
Abstract
In this work we demonstrate for the first time the use of Förster resonance energy transfer (FRET) as an assay to monitor the dynamics of cross-bridge conformational changes directly in single muscle fibres. The advantage of FRET imaging is its ability to measure distances in the nanometre range, relevant for structural changes in actomyosin cross-bridges. To reach this goal we have used several FRET couples to investigate different locations in the actomyosin complex. We exchanged the native essential light chain of myosin with a recombinant essential light chain labelled with various thiol-reactive chromophores. The second fluorophore of the FRET couple was introduced by three approaches: labelling actin, labelling SH1 cysteine and binding an adenosine triphosphate (ATP) analogue. We characterise FRET in rigor cross-bridges: in this condition muscle fibres are well described by a single FRET population model which allows us to evaluate the true FRET efficiency for a single couple and the consequent donor–acceptor distance. The results obtained are in good agreement with the distances expected from crystallographic data. The FRET characterisation presented herein is essential before moving onto dynamic measurements, as the FRET efficiency differences to be detected in an active muscle fibre are on the order of 10–15% of the FRET efficiencies evaluated here. This means that, to obtain reliable results to monitor the dynamics of cross-bridge conformational changes, we had to fully characterise the system in a steady-state condition, demonstrating firstly the possibility to detect FRET and secondly the viability of the present approach to distinguish small FRET variations.
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22
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Tabouillot T, Muddana HS, Butler PJ. Endothelial Cell Membrane Sensitivity to Shear Stress is Lipid Domain Dependent. Cell Mol Bioeng 2010; 4:169-181. [PMID: 22247740 DOI: 10.1007/s12195-010-0136-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Blood flow-associated shear stress causes physiological and pathophysiological biochemical processes in endothelial cells that may be initiated by alterations in plasma membrane lipid domains characterized as liquid-ordered (l(o)), such as rafts or caveolae, or liquid-disordered (l(d)). To test for domain-dependent shear sensitivity, we used time-correlated single photon counting instrumentation to assess the photophysics and dynamics of the domain-selective lipid analogues DiI-C(12) and DiI-C(18) in endothelial cells subjected to physiological fluid shear stress. Under static conditions, DiI-C(12) fluorescence lifetime was less than DiI-C(18) lifetime and the diffusion coefficient of DiI-C(12) was greater than the DiI-C(18) diffusion coefficient, confirming that DiI-C(12) probes l(d), a more fluid membrane environment, and DiI-C(18) probes the l(o) phase. Domains probed by DiI-C(12) exhibited an early (10 s) and transient decrease of fluorescence lifetime after the onset of shear while domains probed by DiI-C(18) exhibited a delayed decrease of fluorescence lifetime that was sustained for the 2 min the cells were subjected to flow. The diffusion coefficient of DiI-C(18) increased after shear imposition, while that of DiI-C(12) remained constant. Determination of the number of molecules (N) in the control volume suggested that DiI-C(12)-labeled domains increased in N immediately after step-shear, while N for DiI-C(18)-stained membrane transiently decreased. These results demonstrate that membrane microdomains are differentially sensitive to fluid shear stress.
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Affiliation(s)
- Tristan Tabouillot
- Department of Bioengineering, The Pennsylvania State University, 205 Hallowell Building, University Park, PA 16802, USA
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23
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Carlin LM, Makrogianneli K, Keppler M, Fruhwirth GO, Ng T. Visualisation of signalling in immune cells. Methods Mol Biol 2010; 616:97-113. [PMID: 20379871 DOI: 10.1007/978-1-60761-461-6_7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Currently, a great number of approaches are employed in investigation of the immune system. These range from experiments in live animals and biochemical techniques to investigate whole organs or cell populations down to single cell and molecular techniques to look at dynamics in specific cell-cell interactions. It is the latter approach that this chapter focusses on. The use of Förster resonance energy transfer (FRET) techniques to probe protein-protein interactions that are involved in receptor signalling to the cytoskeleton in intact cells is now well established. Various FRET biosensors are available to visualise several critical cell processes, giving information about activity and the location of key signalling molecules. As a specific set of examples in this chapter, we have generated variants of the original Rho, Rac and Cdc42 "Raichu" probes and improved their fluorophore combination to make them suitable for FLIM. These were employed in a number of assays to determine signal dynamics in T and NK cells. Specific protocols of how to use these probes and technical notes are described.
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Affiliation(s)
- Leo M Carlin
- Cancer Studies Division/Randall Division of Cellular and Molecular Biophysics, Richard Dimbleby Department of Cancer Research, Guy's Medical School Campus, King's College London, London, UK
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24
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Petrášek Z, Eckert HJ, Kemnitz K. Wide-field photon counting fluorescence lifetime imaging microscopy: application to photosynthesizing systems. PHOTOSYNTHESIS RESEARCH 2009; 102:157-168. [PMID: 19533411 DOI: 10.1007/s11120-009-9444-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 05/19/2009] [Indexed: 05/27/2023]
Abstract
Fluorescence lifetime imaging microscopy (FLIM) is a technique that visualizes the excited state kinetics of fluorescence molecules with the spatial resolution of a fluorescence microscope. We present a scanningless implementation of FLIM based on a time- and spacecorrelated single photon counting (TSCSPC) method employing a position-sensitive quadrant anode detector and wide-field illumination. The standard time-correlated photon counting approach leads to picosecond temporal resolution, making it possible to resolve complex fluorescence decays. This allows parallel acquisition of time-resolved images of biological samples under minimally invasive low-excitation conditions (<10 mW/cm(2)). In this way unwanted photochemical reactions induced by high excitation intensities and distorting the decay kinetics are avoided. Comparably low excitation intensities are practically impossible to achieve with a conventional laser scanning microscope, where focusing of the excitation beam into a tight spot is required. Therefore, wide-field FLIM permits to study Photosystem II (PS II) in a way so far not possible with a laser scanning microscope. The potential of the wide-field TSCSPC method is demonstrated by presenting FLIM measurements of the fluorescence dynamics of photosynthetic systems in living cells of the chlorophyll d-containing cyanobacterium Acaryochloris marina.
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Affiliation(s)
- Zdeněk Petrášek
- Biophysics group, Biotechnologisches Zentrum, Technische Universität Dresden, Tatzberg 47-51, 01307 Dresden, Germany
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25
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Mercatelli R, Quercioli F, Barsanti L, Evangelista V, Coltelli P, Passarelli V, Frassanito AM, Gualtieri P. Intramolecular photo-switching and intermolecular energy transfer as primary photoevents in photoreceptive processes: The case of Euglena gracilis. Biochem Biophys Res Commun 2009; 385:176-80. [DOI: 10.1016/j.bbrc.2009.05.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Accepted: 05/09/2009] [Indexed: 01/28/2023]
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26
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Weidtkamp-Peters S, Felekyan S, Bleckmann A, Simon R, Becker W, Kühnemuth R, Seidel CAM. Multiparameter fluorescence image spectroscopy to study molecular interactions. Photochem Photobiol Sci 2009; 8:470-80. [PMID: 19337660 DOI: 10.1039/b903245m] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multiparameter Fluorescence Image Spectroscopy (MFIS) is used to monitor simultaneously a variety of fluorescence parameters in confocal fluorescence microscopy. As the photons are registered one by one, MFIS allows for fully parallel recording of Fluorescence Correlation/Cross Correlation Spectroscopy (FCS/FCCS), fluorescence lifetime and pixel/image information over time periods of hours with picosecond accuracy. The analysis of the pixel fluorescence information in higher-dimensional histograms maximizes the selectivity of fluorescence microscopic methods. Moreover it facilitates a statistically-relevant data analysis of the pixel information which makes an efficient detection of heterogeneities possible. The reliability of MFIS has been demonstrated for molecular interaction studies in different complex environments: (I) detecting the heterogeneity of diffusion properties of the dye Rhodamine 110 in a sepharose bead, (II) Förster Resonance Energy Transfer (FRET) studies in mammalian HEK293 cells, and (III) FRET study of the homodimerisation of the transcription factor BIM1 in plant cells. The multidimensional analysis of correlated changes of several parameters measured by FRET, FCS, fluorescence lifetime and anisotropy increases the robustness of the analysis significantly. The economic use of photon information allows one to keep the expression levels of fluorescent protein-fusion proteins as low as possible (down to the single-molecule level).
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Affiliation(s)
- Stefanie Weidtkamp-Peters
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany.
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27
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Barber P, Ameer-Beg S, Gilbey J, Carlin L, Keppler M, Ng T, Vojnovic B. Multiphoton time-domain fluorescence lifetime imaging microscopy: practical application to protein–protein interactions using global analysis. J R Soc Interface 2008. [DOI: 10.1098/rsif.2008.0451.focus] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Förster resonance energy transfer (FRET) detected via fluorescence lifetime imaging microscopy (FLIM) and global analysis provide a way in which protein–protein interactions may be spatially localized and quantified within biological cells. The FRET efficiency and proportion of interacting molecules have been determined using bi-exponential fitting to time-domain FLIM data from a multiphoton time-correlated single-photon counting microscope system. The analysis has been made more robust to noise and significantly faster using global fitting, allowing higher spatial resolutions and/or lower acquisition times. Data have been simulated, as well as acquired from cell experiments, and the accuracy of a modified Levenberg–Marquardt fitting technique has been explored. Multi-image global analysis has been used to follow the epidermal growth factor-induced activation of Cdc42 in a short-image-interval time-lapse FLIM/FRET experiment. Our implementation offers practical analysis and time-resolved-image manipulation, which have been targeted towards providing fast execution, robustness to low photon counts, quantitative results and amenability to automation and batch processing.
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Affiliation(s)
- P.R Barber
- University of Oxford Gray Cancer Institute, Mount Vernon HospitalMiddlesex HA6 2JR, UK
| | - S.M Ameer-Beg
- University of Oxford Gray Cancer Institute, Mount Vernon HospitalMiddlesex HA6 2JR, UK
- King's College London, Randall CentreNew Hunt's House, Guy's Medical School Campus, London SE1 1UL, UK
| | - J Gilbey
- University of Oxford Gray Cancer Institute, Mount Vernon HospitalMiddlesex HA6 2JR, UK
| | - L.M Carlin
- King's College London, Randall CentreNew Hunt's House, Guy's Medical School Campus, London SE1 1UL, UK
| | - M Keppler
- King's College London, Randall CentreNew Hunt's House, Guy's Medical School Campus, London SE1 1UL, UK
| | - T.C Ng
- King's College London, Randall CentreNew Hunt's House, Guy's Medical School Campus, London SE1 1UL, UK
| | - B Vojnovic
- University of Oxford Gray Cancer Institute, Mount Vernon HospitalMiddlesex HA6 2JR, UK
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28
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Roberts MS, Roberts MJ, Robertson TA, Sanchez W, Thörling C, Zou Y, Zhao X, Becker W, Zvyagin AV. In vitro and in vivo imaging of xenobiotic transport in human skin and in the rat liver. JOURNAL OF BIOPHOTONICS 2008; 1:478-93. [PMID: 19343674 DOI: 10.1002/jbio.200810058] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Multiphoton tomography was used to examine xenobiotic transport in vivo. We used the photochemical properties of zinc oxide and fluorescein and multiphoton tomography to study their transport in the skin and in the rat liver in vivo. Zinc oxide nanoparticles were visualised in human skin using the photoluminescence properties of zinc oxide and either a selective emission wavelength band pass filter or a filter with fluorescence lifetime imaging (FLIM). Zinc oxide nanoparticles (30 nm) did not penetrate into human skin in vitro and in vivo and this was validated by scanning electron microscopy with X-ray photoelectron spectroscopy. Fluorescein was measured in the liver using FLIM. Fluorescein is rapidly extracted from the blood into the liver cells and then transported into the bile. It is suggested that multiphoton tomography may be of particular use in defining in vivo 4D (in both space and time) pharmacokinetics.
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Affiliation(s)
- Michael S Roberts
- Therapeutics Research Unit, Department of Medicine, University of Queensland, Princess Alexandra Hospital, Woolloongabba, QLD 4102, Australia.
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29
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Selective detection of NADPH oxidase in polymorphonuclear cells by means of NAD(P)H-based fluorescence lifetime imaging. JOURNAL OF BIOPHYSICS 2008; 2008:602639. [PMID: 20107577 PMCID: PMC2809359 DOI: 10.1155/2008/602639] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Accepted: 09/02/2008] [Indexed: 11/18/2022]
Abstract
NADPH oxidase (NOX2) is a multisubunit membrane-bound enzyme complex that, upon assembly in activated cells,
catalyses the reduction of free oxygen to its superoxide anion, which further leads to reactive oxygen species (ROS) that are
toxic to invading pathogens, for example, the fungus Aspergillus fumigatus. Polymorphonuclear cells (PMNs) employ both
nonoxidative and oxidative mechanisms to clear this fungus from the lung. The oxidative mechanisms mainly depend on the
proper assembly and function of NOX2. We identified for the first time the NAD(P)H-dependent enzymes involved in such
oxidative mechanisms by means of biexponential NAD(P)H-fluorescence lifetime imaging (FLIM). A specific fluorescence
lifetime of 3670±140 picoseconds as compared to 1870 picoseconds for NAD(P)H bound to mitochondrial enzymes could be
associated with NADPH bound to oxidative enzymes in activated PMNs. Due to its predominance in PMNs and due to the
use of selective activators and inhibitors, we strongly believe that this specific lifetime mainly originates from NOX2. Our
experiments also revealed the high site specificity of the NOX2 assembly and, thus, of the ROS production as well as the
dynamic nature of these phenomena. On the example of NADPH oxidase, we demonstrate the potential of NAD(P)H-based
FLIM in selectively investigating enzymes during their cellular function.
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30
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Petrášek Z, Schwille P. Fluctuations as a source of information in fluorescence microscopy. J R Soc Interface 2008. [DOI: 10.1098/rsif.2008.0200.focus] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Fluctuations in fluorescence spectroscopy and microscopy have traditionally been regarded as noise—they lower the resolution and contrast and do not permit high acquisition rates. However, fluctuations can also be used to gain additional information about a system. This fact has been exploited in single-point microscopic techniques, such as fluorescence correlation spectroscopy and analysis of single molecule trajectories, and also in the imaging field, e.g. in spatio-temporal image correlation spectroscopy. Here, we discuss how fluctuations are used to obtain more quantitative information from the data than that given by average values, while minimizing the effects of noise due to stochastic photon detection.
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Affiliation(s)
- Zdeněk Petrášek
- Biophysics group, Biotechnologisches Zentrum, Technische Universität DresdenTatzberg 47-51, 01307 Dresden, Germany
| | - Petra Schwille
- Biophysics group, Biotechnologisches Zentrum, Technische Universität DresdenTatzberg 47-51, 01307 Dresden, Germany
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31
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Characterization of protein dynamics in asymmetric cell division by scanning fluorescence correlation spectroscopy. Biophys J 2008; 95:5476-86. [PMID: 18805921 DOI: 10.1529/biophysj.108.135152] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The development and differentiation of complex organisms from the single fertilized egg is regulated by a variety of processes that all rely on the distribution and interaction of proteins. Despite the tight regulation of these processes with respect to temporal and spatial protein localization, exact quantification of the underlying parameters, such as concentrations and distribution coefficients, has so far been problematic. Recent experiments suggest that fluorescence correlation spectroscopy on a single molecule level in living cells has great promise in revealing these parameters with high precision. The optically challenging situation in multicellular systems such as embryos can be ameliorated by two-photon excitation, where scattering background and cumulative photobleaching is limited. A more severe problem is posed by the large range of molecular mobilities observed at the same time, as standard FCS relies strongly on the presence of mobility-induced fluctuations. In this study, we overcame the limitations of standard FCS. We analyzed in vivo polarity protein PAR-2 from eggs of Caenorhabditis elegans by beam-scanning FCS in the cytosol and on the cortex of C. elegans before asymmetric cell division. The surprising result is that the distribution of PAR-2 is largely uncoupled from the movement of cytoskeletal components of the cortex. These results call for a more systematic future investigation of the different cortical elements, and show that the FCS technique can contribute to answering these questions, by providing a complementary approach that can reveal insights not obtainable by other techniques.
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Bayle V, Nussaume L, Bhat RA. Combination of novel green fluorescent protein mutant TSapphire and DsRed variant mOrange to set up a versatile in planta FRET-FLIM assay. PLANT PHYSIOLOGY 2008; 148:51-60. [PMID: 18621983 PMCID: PMC2528103 DOI: 10.1104/pp.108.117358] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Accepted: 07/05/2008] [Indexed: 05/22/2023]
Abstract
Förster resonance energy transfer (FRET) measurements based on fluorescence lifetime imaging microscopy (FLIM) are increasingly being used to assess molecular conformations and associations in living systems. Reduction in the excited-state lifetime of the donor fluorophore in the presence of an appropriately positioned acceptor is taken as strong evidence of FRET. Traditionally, cyan fluorescent protein has been widely used as a donor fluorophore in FRET experiments. However, given its photolabile nature, low quantum yield, and multiexponential lifetime, cyan fluorescent protein is far from an ideal donor in FRET imaging. Here, we report the application and use of the TSapphire mutant of green fluorescent protein as an efficient donor to mOrange in FLIM-based FRET imaging in intact plant cells. Using time-correlated single photon counting-FLIM, we show that TSapphire expressed in living plant cells decays with lifetime of 2.93 +/- 0.09 ns. Chimerically linked TSapphire and mOrange (with 16-amino acid linker in between) exhibit substantial energy transfer based on the reduction in the lifetime of TSapphire in the presence of the acceptor mOrange. Experiments performed with various genetically and/or biochemically known interacting plant proteins demonstrate the versatility of the FRET-FLIM system presented here in different subcellular compartments tested (cytosol, nucleus, and at plasma membrane). The better spectral overlap with red monomers, higher photostability, and monoexponential lifetime of TSapphire makes it an ideal FRET-FLIM donor to study protein-protein interactions in diverse eukaryotic systems overcoming, in particular, many technical challenges encountered (like autofluorescence of cell walls and fluorescence of pigments associated with photosynthetic apparatus) while studying plant protein dynamics and interactions.
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Affiliation(s)
- Vincent Bayle
- Laboratory of Plant Developmental Biology, Service of Plant Biology and Environmental Microbiology/Institute for Biotechnology and Environmental Biology, UMR6191 CEA/CNRS/Mediterranean University Aix-Marseille, St. Paul Lez Durance, France
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Niesner RA, Andresen V, Gunzer M. Intravital two-photon microscopy: focus on speed and time resolved imaging modalities. Immunol Rev 2008; 221:7-25. [PMID: 18275472 DOI: 10.1111/j.1600-065x.2008.00582.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Initially used mainly in the neurosciences, two-photon microscopy has become a powerful tool for the analysis of immunological processes. Here, we describe currently available two-photon microscopy techniques with a focus on novel approaches that allow very high image acquisition rates compared with state-of-the-art systems. This improvement is achieved through a parallelization of the excitation process: multiple beams scan the sample simultaneously, and the fluorescence is collected with sensitive charge-coupled device (CCD)-based line or field detectors. The new technique's performance is compared with conventional single beam laser-scanning systems that detect signals by means of photomultipliers. We also discuss the use of time- and polarization-resolved fluorescence detection, especially fluorescence lifetime imaging (FLIM), which goes beyond simple detection of cells and tissue structures and allows insight into cellular physiology. We focus on the analysis of endogenous fluorophores such as NAD(P)H as a way to analyze the redox status in cells with subcellular resolution. Here, high-speed imaging setups in combination with novel ways of data analysis allow the generation of FLIM data sets almost in real time. The implications of this technology for the analysis of immune reactions and other cellular processes are discussed.
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Affiliation(s)
- Raluca A Niesner
- Junior Research Group Immunodynamics, Helmholtz Centre for Infection Research, Braunschweig, Germany
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Petrov EP, Schwille P. State of the Art and Novel Trends in Fluorescence Correlation Spectroscopy. SPRINGER SERIES ON FLUORESCENCE 2008. [DOI: 10.1007/4243_2008_032] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Butler PJ, Dong C, Snyder AJ, Jones AD, Sheets ED. Bioengineering and Bioinformatics Summer Institutes: meeting modern challenges in undergraduate summer research. CBE LIFE SCIENCES EDUCATION 2008; 7:45-53. [PMID: 18316807 PMCID: PMC2262124 DOI: 10.1187/cbe.07-08-0064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Accepted: 11/12/2007] [Indexed: 05/06/2023]
Abstract
Summer undergraduate research programs in science and engineering facilitate research progress for faculty and provide a close-ended research experience for students, which can prepare them for careers in industry, medicine, and academia. However, ensuring these outcomes is a challenge when the students arrive ill-prepared for substantive research or if projects are ill-defined or impractical for a typical 10-wk summer. We describe how the new Bioengineering and Bioinformatics Summer Institutes (BBSI), developed in response to a call for proposals by the National Institutes of Health (NIH) and the National Science Foundation (NSF), provide an impetus for the enhancement of traditional undergraduate research experiences with intense didactic training in particular skills and technologies. Such didactic components provide highly focused and qualified students for summer research with the goal of ensuring increased student satisfaction with research and mentor satisfaction with student productivity. As an example, we focus on our experiences with the Penn State Biomaterials and Bionanotechnology Summer Institute (PSU-BBSI), which trains undergraduates in core technologies in surface characterization, computational modeling, cell biology, and fabrication to prepare them for student-centered research projects in the role of materials in guiding cell biology.
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Affiliation(s)
- Peter J Butler
- Department of Bioengineering, Penn State College of Medicine, Hershey, PA 17033, USA.
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Jones PB, Rozkalne A, Meyer-Luehmann M, Spires-Jones TL, Makarova A, Kumar ATN, Berezovska O, Bacskai BB, Hyman BT. Two postprocessing techniques for the elimination of background autofluorescence for fluorescence lifetime imaging microscopy. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:014008. [PMID: 18315366 DOI: 10.1117/1.2837169] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The analysis of fluorescence lifetime imaging microscopy (FLIM) data under complex biological conditions can be challenging. Particularly, the presence of short-lived autofluorescent aggregates can confound lifetime measurements in fluorescence energy transfer (FRET) experiments, where it can become confused with the signal from exogenous fluorophores. Here we report two techniques that can be used to discriminate the contribution of autofluorescence from exogenous fluorphores in FLIM. We apply the techniques to transgenic mice that natively express yellow fluorescence protein (YFP) in a subset of cortical neurons and to histological slices of aged human brain tissue, where we study the misfolding of intracellular tau protein in the form of neurofibrillary tangles.
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Affiliation(s)
- Phillip B Jones
- Harvard Medical School, Massachusetts General Hospital, MassGeneral Institute for Neurodegenerative Disorders, 114 16th Street, Charlestown, Massachusetts 02129, USA
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Rück A, Hülshoff C, Kinzler I, Becker W, Steiner R. SLIM: A new method for molecular imaging. Microsc Res Tech 2007; 70:485-92. [PMID: 17366616 DOI: 10.1002/jemt.20433] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We used spectrally resolved fluorescence lifetime imaging (SLIM) to investigate the mitochondria staining dye rhodamine 123 and binding of DAPI to RNA and DNA in cells. Moreover, different components of the photosensitizer Photofrin were resolved in cell cultures by SLIM. To record lifetime images (tau-mapping) with spectral resolution we used a laser scanning microscope equipped with a spectrograph, a 16 channel multianode PMT, and multidimensional time-correlated single photon counting. A Ti:Saphir laser was used for excitation or alternatively a ps diode laser. With this system the time- and spectral-resolved fluorescence characteristics of different fluorophores were investigated in cell cultures. As an example, the mitochondria staining dye rhodamine I23 could be easily distinguished from DAPI, which binds to nucleic acids. Also different binding sites of DAPI could be discriminated. This was proved by the appearance of different lifetime components within different spectral channels. Moreover, we were able to detect monomeric and aggregated forms of Photofrin in cells. Different lifetimes could be attributed to the various compounds. In addition, a detailed analysis of the autofluorescence by SLIM could explain changes of mitochondrial metabolism during Photofrin-PDT.
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Affiliation(s)
- A Rück
- Institute for Laser Technologies in Medicine and Metrology, Helmholtzstr. 12, 89081 Ulm, Germany.
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Caorsi V, Ronzitti E, Vicidomini G, Krol S, McConnell G, Diaspro A. FRET measurements on fuzzy fluorescent nanostructures. Microsc Res Tech 2007; 70:452-8. [PMID: 17393494 DOI: 10.1002/jemt.20444] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the last decade, fluorescence resonance energy transfer (FRET) has become a useful technique for studying intermolecular interactions applied to the analysis of biological systems. Although FRET measurements may be very helpful in the comprehension of different cellular processes, it can be difficult to obtain quantitative results, hence the necessity of studying FRET on controllable systems. Here, a fuzzy nanostructured system called a nanocapsule is presented as a nanometric-device allowing distance modulation, thus preserving photophysical properties of fluorescent dyes and exhibiting good potential features for improving quantitative FRET analysis. We evaluated the behavior of such a sample using four FRET methods (three of them based on steady-state fluorescence and one using lifetime measurements). Within some limitations that can be overcome, these nanodevices have the potential to serve as a benchmark system for characterizing new FRET couples and to develop quantitative approaches for FRET analysis.
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Affiliation(s)
- V Caorsi
- LAMBS, MicroScoBIO Research Center, Department of Physics (DIFI), University of Genoa, Genoa, Italy.
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Gullapalli RR, Tabouillot T, Mathura R, Dangaria JH, Butler PJ. Integrated multimodal microscopy, time-resolved fluorescence, and optical-trap rheometry: toward single molecule mechanobiology. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:014012. [PMID: 17343487 PMCID: PMC3251961 DOI: 10.1117/1.2673245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Cells respond to forces through coordinated biochemical signaling cascades that originate from changes in single-molecule structure and dynamics and proceed to large-scale changes in cellular morphology and protein expression. To enable experiments that determine the molecular basis of mechanotransduction over these large time and length scales, we construct a confocal molecular dynamics microscope (CMDM). This system integrates total-internal-reflection fluorescence (TIRF), epifluorescence, differential interference contrast (DIC), and 3-D deconvolution imaging modalities with time-correlated single-photon counting (TCSPC) instrumentation and an optical trap. Some of the structures hypothesized to be involved in mechanotransduction are the glycocalyx, plasma membrane, actin cytoskeleton, focal adhesions, and cell-cell junctions. Through analysis of fluorescence fluctuations, single-molecule spectroscopic measurements [e.g., fluorescence correlation spectroscopy (FCS) and time-resolved fluorescence] can be correlated with these subcellular structures in adherent endothelial cells subjected to well-defined forces. We describe the construction of our multimodal microscope in detail and the calibrations necessary to define molecular dynamics in cell and model membranes. Finally, we discuss the potential applications of the system and its implications for the field of mechanotransduction.
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Affiliation(s)
- Ramachandra R Gullapalli
- The Pennsylvania State University, Department of Bioengineering, 205 Hallowell Building, University Park, Pennsylvania 16802, USA
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MESH Headings
- Biology/methods
- Fluorescent Dyes/chemistry
- Fluorescent Dyes/metabolism
- Half-Life
- Image Processing, Computer-Assisted/instrumentation
- Image Processing, Computer-Assisted/methods
- Microscopy, Fluorescence/instrumentation
- Microscopy, Fluorescence/methods
- Microscopy, Fluorescence, Multiphoton/instrumentation
- Microscopy, Fluorescence, Multiphoton/methods
- Microscopy, Video/instrumentation
- Microscopy, Video/methods
- Models, Biological
- Models, Theoretical
- Spectrometry, Fluorescence/methods
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Affiliation(s)
- Ching-Wei Chang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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Yan L, Rueden CT, White JG, Eliceiri KW. Applications of combined spectral lifetime microscopy for biology. Biotechniques 2006; 41:249, 251, 253 passim. [PMID: 16989084 DOI: 10.2144/000112251] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Live cell imaging has been greatly advanced by the recent development of new fluorescence microscopy-based methods such as multiphoton laser-scanning microscopy, which can noninvasively image deep into live specimens and generate images of extrinsic and intrinsic signals. Of recent interest has been the development of techniques that can harness properties of fluorescence, other than intensity, such as the emission spectrum and excited state lifetime of a fluorophore. Spectra can be used to discriminate between fluorophores, and lifetime can be used to report on the microenvironment of fluorophores. We describe a novel technique-combined spectral and lifetime imaging-which combines the benefits of multiphoton microscopy, spectral discrimination, and lifetime analysis and allows for the simultaneous collection of all three dimensions of data along with spatial and temporal information.
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Affiliation(s)
- Long Yan
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin-Madison, Madison, WI, USA
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Kudryavtsev V, Felekyan S, Woźniak AK, König M, Sandhagen C, Kühnemuth R, Seidel CAM, Oesterhelt F. Monitoring dynamic systems with multiparameter fluorescence imaging. Anal Bioanal Chem 2006; 387:71-82. [PMID: 17160654 DOI: 10.1007/s00216-006-0917-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 10/05/2006] [Accepted: 10/09/2006] [Indexed: 10/23/2022]
Abstract
A new general strategy based on the use of multiparameter fluorescence detection (MFD) to register and quantitatively analyse fluorescence images is introduced. Multiparameter fluorescence imaging (MFDi) uses pulsed excitation, time-correlated single-photon counting and a special pixel clock to simultaneously monitor the changes in the eight-dimensional fluorescence information (fundamental anisotropy, fluorescence lifetime, fluorescence intensity, time, excitation spectrum, fluorescence spectrum, fluorescence quantum yield, distance between fluorophores) in real time. The three spatial coordinates are also stored. The most statistically efficient techniques known from single-molecule spectroscopy are used to estimate fluorescence parameters of interest for all pixels, not just for the regions of interest. Their statistical significance is judged from a stack of two-dimensional histograms. In this way, specific pixels can be selected for subsequent pixel-based subensemble analysis in order to improve the statistical accuracy of the parameters estimated. MFDi avoids the need for sequential measurements, because the registered data allow one to perform many analysis techniques, such as fluorescence-intensity distribution analysis (FIDA) and fluorescence correlation spectroscopy (FCS), in an off-line mode. The limitations of FCS for counting molecules and monitoring dynamics are discussed. To demonstrate the ability of our technique, we analysed two systems: (i) interactions of the fluorescent dye Rhodamine 110 inside and outside of a glutathione sepharose bead, and (ii) microtubule dynamics in live yeast cells of Schizosaccharomyces pombe using a fusion protein of Green Fluorescent Protein (GFP) with Minichromosome Altered Loss Protein 3 (Mal3), which is involved in the dynamic cycle of polymerising and depolymerising microtubules.
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Affiliation(s)
- Volodymyr Kudryavtsev
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
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