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Sakagami K, Igawa T, Saikawa K, Sakaguchi Y, Hossain N, Kato C, Kinemori K, Suzuki N, Suzuki M, Kawaguchi A, Ochi H, Tajika Y, Ogino H. Development of a heat-stable alkaline phosphatase reporter system for cis-regulatory analysis and its application to 3D digital imaging of Xenopus embryonic tissues. Dev Growth Differ 2024; 66:256-265. [PMID: 38439617 DOI: 10.1111/dgd.12919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 03/06/2024]
Abstract
Xenopus is one of the essential model systems for studying vertebrate development. However, one drawback of this system is that, because of the opacity of Xenopus embryos, 3D imaging analysis is limited to surface structures, explant cultures, and post-embryonic tadpoles. To develop a technique for 3D tissue/organ imaging in whole Xenopus embryos, we identified optimal conditions for using placental alkaline phosphatase (PLAP) as a transgenic reporter and applied it to the correlative light microscopy and block-face imaging (CoMBI) method for visualization of PLAP-expressing tissues/organs. In embryos whose endogenous alkaline phosphatase activities were heat-inactivated, PLAP staining visualized various tissue-specific enhancer/promoter activities in a manner consistent with green fluorescent protein (GFP) fluorescence. Furthermore, PLAP staining appeared to be more sensitive than GFP fluorescence as a reporter, and the resulting expression patterns were not mosaic, in striking contrast to the mosaic staining pattern of β-galactosidase expressed from the lacZ gene that was introduced by the same transgenesis method. Owing to efficient penetration of alkaline phosphatase substrates, PLAP activity was detected in deep tissues, such as the developing brain, spinal cord, heart, and somites, by whole-mount staining. The stained embryos were analyzed by the CoMBI method, resulting in the digital reconstruction of 3D images of the PLAP-expressing tissues. These results demonstrate the efficacy of the PLAP reporter system for detecting enhancer/promoter activities driving deep tissue expression and its combination with the CoMBI method as a powerful approach for 3D digital imaging analysis of specific tissue/organ structures in Xenopus embryos.
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Affiliation(s)
- Kiyo Sakagami
- Department of Animal Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Japan
| | - Takeshi Igawa
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Kaori Saikawa
- Department of Animal Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Japan
| | - Yusuke Sakaguchi
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Nusrat Hossain
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
| | - Chiho Kato
- Department of Animal Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Japan
| | - Kazuhito Kinemori
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Nanoka Suzuki
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Makoto Suzuki
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Akane Kawaguchi
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Shizuoka, Japan
| | - Haruki Ochi
- Institute for Promotion of Medical Science Research, Faculty of Medicine, Yamagata University, Yamagata, Japan
| | - Yuki Tajika
- Department of Radiological Technology, Gunma Prefectural College of Health Sciences, Maebashi, Japan
| | - Hajime Ogino
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
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Gooz M, Maldonado EN. Fluorescence microscopy imaging of mitochondrial metabolism in cancer cells. Front Oncol 2023; 13:1152553. [PMID: 37427141 PMCID: PMC10326048 DOI: 10.3389/fonc.2023.1152553] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 06/06/2023] [Indexed: 07/11/2023] Open
Abstract
Mitochondrial metabolism is an important contributor to cancer cell survival and proliferation that coexists with enhanced glycolytic activity. Measuring mitochondrial activity is useful to characterize cancer metabolism patterns, to identify metabolic vulnerabilities and to identify new drug targets. Optical imaging, especially fluorescent microscopy, is one of the most valuable tools for studying mitochondrial bioenergetics because it provides semiquantitative and quantitative readouts as well as spatiotemporal resolution of mitochondrial metabolism. This review aims to acquaint the reader with microscopy imaging techniques currently used to determine mitochondrial membrane potential (ΔΨm), nicotinamide adenine dinucleotide (NADH), ATP and reactive oxygen species (ROS) that are major readouts of mitochondrial metabolism. We describe features, advantages, and limitations of the most used fluorescence imaging modalities: widefield, confocal and multiphoton microscopy, and fluorescent lifetime imaging (FLIM). We also discus relevant aspects of image processing. We briefly describe the role and production of NADH, NADHP, flavins and various ROS including superoxide and hydrogen peroxide and discuss how these parameters can be analyzed by fluorescent microscopy. We also explain the importance, value, and limitations of label-free autofluorescence imaging of NAD(P)H and FAD. Practical hints for the use of fluorescent probes and newly developed sensors for imaging ΔΨm, ATP and ROS are described. Overall, we provide updated information about the use of microscopy to study cancer metabolism that will be of interest to all investigators regardless of their level of expertise in the field.
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Affiliation(s)
- Monika Gooz
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC, United States
- Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States
| | - Eduardo N. Maldonado
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC, United States
- Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States
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Bai H, Che B, Zhao T, Zhao W, Wang K, Zhang C, Bai J. Feature Extraction of 3T3 Fibroblast Microtubule Based on Discrete Wavelet Transform and Lucy–Richardson Deconvolution Methods. MICROMACHINES 2022; 13:mi13060824. [PMID: 35744438 PMCID: PMC9228624 DOI: 10.3390/mi13060824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/21/2022] [Accepted: 05/22/2022] [Indexed: 11/16/2022]
Abstract
Accompanied by the increasing requirements of the probing micro/nanoscopic structures of biological samples, various image-processing algorithms have been developed for visualization or to facilitate data analysis. However, it remains challenging to enhance both the signal-to-noise ratio and image resolution using a single algorithm. In this investigation, we propose a composite image processing method by combining discrete wavelet transform (DWT) and the Lucy–Richardson (LR) deconvolution method, termed the DWDC method. Our results demonstrate that the signal-to-noise ratio and resolution of live cells’ microtubule networks are considerably improved, allowing the recognition of features as small as 120 nm. The method shows robustness in processing the high-noise images of filament-like biological structures, e.g., the cytoskeleton networks captured by fluorescent microscopes.
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Affiliation(s)
- Haoxin Bai
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi’an 710127, China; (H.B.); (B.C.); (K.W.); (J.B.)
| | - Bingchen Che
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi’an 710127, China; (H.B.); (B.C.); (K.W.); (J.B.)
| | - Tianyun Zhao
- School of Automation, Northwestern Polytechnical University, Xi’an 710129, China;
| | - Wei Zhao
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi’an 710127, China; (H.B.); (B.C.); (K.W.); (J.B.)
- Correspondence: (W.Z.); (C.Z.)
| | - Kaige Wang
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi’an 710127, China; (H.B.); (B.C.); (K.W.); (J.B.)
| | - Ce Zhang
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi’an 710127, China; (H.B.); (B.C.); (K.W.); (J.B.)
- Correspondence: (W.Z.); (C.Z.)
| | - Jintao Bai
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi’an 710127, China; (H.B.); (B.C.); (K.W.); (J.B.)
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Seeger M, Soliman D, Aguirre J, Diot G, Wierzbowski J, Ntziachristos V. Pushing the boundaries of optoacoustic microscopy by total impulse response characterization. Nat Commun 2020; 11:2910. [PMID: 32518250 PMCID: PMC7283257 DOI: 10.1038/s41467-020-16565-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 04/22/2020] [Indexed: 11/19/2022] Open
Abstract
Optical microscopy improves in resolution and signal-to-noise ratio by correcting for the system’s point spread function; a measure of how a point source is resolved, typically determined by imaging nanospheres. Optical-resolution optoacoustic (photoacoustic) microscopy could be similarly corrected, especially to account for the spatially-dependent signal distortions induced by the acoustic detection and the time-resolved and bi-polar nature of optoacoustic signals. Correction algorithms must therefore include the spatial dependence of signals’ origins and profiles in time, i.e. the four-dimensional total impulse response (TIR). However, such corrections have been so far impeded by a lack of efficient TIR-characterization methods. We introduce high-quality TIR determination based on spatially-distributed optoacoustic point sources (SOAPs), produced by scanning an optical focus on an axially-translatable 250 nm gold layer. Using a spatially-dependent TIR-correction improves the signal-to-noise ratio by >10 dB and the axial resolution by ~30%. This accomplishment displays a new performance paradigm for optoacoustic microscopy. Characterizing the total impulse response (TIR) of photoacoustic microscopes has been challenging due to difficulties distributing appropriate point sources. Here, the authors present a method for 3D generation of spatially-distributed optoacoustic point sources and show that subsequent TIR correction results in improved image quality.
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Affiliation(s)
- Markus Seeger
- Chair of Biological Imaging, TranslaTUM, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Dominik Soliman
- Chair of Biological Imaging, TranslaTUM, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Juan Aguirre
- Chair of Biological Imaging, TranslaTUM, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Gael Diot
- Chair of Biological Imaging, TranslaTUM, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Jakob Wierzbowski
- Walter Schottky Institute, Physics Department, Technical University of Munich, Am Coulombwall 4, 85748, Garching, Germany
| | - Vasilis Ntziachristos
- Chair of Biological Imaging, TranslaTUM, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany. .,Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.
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Sorbello C, Etchenique R. Intrinsic optical sectioning with upconverting nanoparticles. Chem Commun (Camb) 2018; 54:1861-1864. [DOI: 10.1039/c7cc08443a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Scanning laser upconversion microscopy yields true multiphoton sectioning power at very low excitation densities.
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Affiliation(s)
- C. Sorbello
- Departamento de Química Inorgánica
- Analítica y Química Física
- INQUIMAE
- Facultad de Ciencias Exactas y Naturales
- Universidad de Buenos Aires
| | - R. Etchenique
- Departamento de Química Inorgánica
- Analítica y Química Física
- INQUIMAE
- Facultad de Ciencias Exactas y Naturales
- Universidad de Buenos Aires
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Kim MJ, Shin YC, Lee JH, Jun SW, Kim CS, Lee Y, Park JC, Lee SH, Park KD, Han DW. Multiphoton imaging of myogenic differentiation in gelatin-based hydrogels as tissue engineering scaffolds. Biomater Res 2016; 20:2. [PMID: 26783450 PMCID: PMC4716633 DOI: 10.1186/s40824-016-0050-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 01/04/2016] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Hydrogels can serve as three-dimensional (3D) scaffolds for cell culture and be readily injected into the body. Recent advances in the image technology for 3D scaffolds like hydrogels have attracted considerable attention to overcome the drawbacks of ordinary imaging technologies such as optical and fluorescence microscopy. Multiphoton microscopy (MPM) is an effective method based on the excitation of two-photons. In the present study, C2C12 myoblasts differentiated in 3D gelatin hydroxyphenylpropionic acid (GHPA) hydrogels were imaged by using a custom-built multiphoton excitation fluorescence microscopy to compare the difference in the imaging capacity between conventional microscopy and MPM. RESULTS The physicochemical properties of GHPA hydrogels were characterized by using scanning electron microscopy and Fourier-transform infrared spectroscopy. In addition, the cell viability and proliferation of C2C12 myoblasts cultured in the GHPA hydrogels were analyzed by using Live/Dead Cell and CCK-8 assays, respectively. It was found that C2C12 cells were well grown and normally proliferated in the hydrogels. Furthermore, the hydrogels were shown to be suitable to facilitate the myogenic differentiation of C2C12 cells incubated in differentiation media, which had been corroborated by MPM. It was very hard to get clear images from a fluorescence microscope. CONCLUSIONS Our findings suggest that the gelatin-based hydrogels can be beneficially utilized as 3D scaffolds for skeletal muscle engineering and that MPM can be effectively applied to imaging technology for tissue regeneration.
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Affiliation(s)
- Min Jeong Kim
- />Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan, 46241 Korea
| | - Yong Cheol Shin
- />Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan, 46241 Korea
| | - Jong Ho Lee
- />Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan, 46241 Korea
| | - Seung Won Jun
- />Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan, 46241 Korea
| | - Chang-Seok Kim
- />Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan, 46241 Korea
| | - Yunki Lee
- />Department of Molecular Science and Technology, Ajou University, Suwon, 16499 Korea
| | - Jong-Chul Park
- />Department of Medical Engineering, Cellbiocontrol Laboratory, Yonsei University College of Medicine, Seoul, 03722 Korea
| | - Soo-Hong Lee
- />Department of Biomedical Science, CHA University, Gyeonggi-do, 11160 Korea
| | - Ki Dong Park
- />Department of Molecular Science and Technology, Ajou University, Suwon, 16499 Korea
| | - Dong-Wook Han
- />Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan, 46241 Korea
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Dao L, Glancy B, Lucotte B, Chang LC, Balaban RS, Hsu LY. A Model-based approach for microvasculature structure distortion correction in two-photon fluorescence microscopy images. J Microsc 2015. [PMID: 26224257 DOI: 10.1111/jmi.12281] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This paper investigates a postprocessing approach to correct spatial distortion in two-photon fluorescence microscopy images for vascular network reconstruction. It is aimed at in vivo imaging of large field-of-view, deep-tissue studies of vascular structures. Based on simple geometric modelling of the object-of-interest, a distortion function is directly estimated from the image volume by deconvolution analysis. Such distortion function is then applied to subvolumes of the image stack to adaptively adjust for spatially varying distortion and reduce the image blurring through blind deconvolution. The proposed technique was first evaluated in phantom imaging of fluorescent microspheres that are comparable in size to the underlying capillary vascular structures. The effectiveness of restoring three-dimensional (3D) spherical geometry of the microspheres using the estimated distortion function was compared with empirically measured point-spread function. Next, the proposed approach was applied to in vivo vascular imaging of mouse skeletal muscle to reduce the image distortion of the capillary structures. We show that the proposed method effectively improve the image quality and reduce spatially varying distortion that occurs in large field-of-view deep-tissue vascular dataset. The proposed method will help in qualitative interpretation and quantitative analysis of vascular structures from fluorescence microscopy images.
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Affiliation(s)
- Lam Dao
- Laboratory of Cardiac Energetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A.,Department of Electrical Engineering and Computer Science, The Catholic University of America, Washington, District of Columbia, U.S.A
| | - Brian Glancy
- Laboratory of Cardiac Energetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - Bertrand Lucotte
- Laboratory of Cardiac Energetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - Lin-Ching Chang
- Department of Electrical Engineering and Computer Science, The Catholic University of America, Washington, District of Columbia, U.S.A
| | - Robert S Balaban
- Laboratory of Cardiac Energetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - Li-Yueh Hsu
- Laboratory of Cardiac Energetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
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Sun Y, Periasamy A. Localizing protein-protein interactions in living cells using fluorescence lifetime imaging microscopy. Methods Mol Biol 2015; 1251:83-107. [PMID: 25391796 DOI: 10.1007/978-1-4939-2080-8_6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In the past decade, advances in fluorescence lifetime imaging have extensively applied in the life sciences, from fundamental biological investigations to advanced clinical diagnosis. Fluorescence lifetime imaging microscopy (FLIM) is now routinely used in the biological sciences to monitor dynamic signaling events inside living cells, e.g., Protein-Protein interactions. In this chapter, we describe the calibration of both time-correlated single-photon counting (TCSPC) and frequency domain (FD) FLIM systems and the acquisition and analysis of FLIM-FRET data for investigating Protein-Protein interactions in living cells.
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Affiliation(s)
- Yuansheng Sun
- W.M. Keck Center for Cellular Imaging, Biology, University of Virginia, B005 Physical and Life Sciences Building, White Head Road, Charlottesville, VA, 22904, USA
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Raut SL, Shumilov D, Chib R, Rich R, Gryczynski Z, Gryczynski I. Two Photon Induced Luminescence of BSA Protected Gold Clusters. Chem Phys Lett 2013; 561-562:74-76. [PMID: 26635417 PMCID: PMC4665100 DOI: 10.1016/j.cplett.2013.01.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In this short letter, we have synthesized the BSA protected Au25 nanoclusters and studied their two photon luminescence behavior. We demonstrate that BSA Au25 nanoclusters can be used as a probe with two photon excitation capability. Our results show a quadratic relation between excitation power and emission intensity whereas with one photon excitation shows a linear dependence. The emission spectrum of BSA Au25 nanoclusters with one photon and two photon excitation shows no appreciable change. Due to its long wavelength emission (650 nm) and two photon excitation, BSA Au25 can be potentially used as a probe for deep tissue imaging.
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Affiliation(s)
- Sangram L. Raut
- Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center, 3500 Camp Bowie Blvd. Fort Worth, Texas, USA, 76107
| | - Dmytro Shumilov
- Department of Physics. Texas Christian University, 2800 S. University Dr., Fort Worth, Texas, USA, 76129
| | - Rahul Chib
- Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center, 3500 Camp Bowie Blvd. Fort Worth, Texas, USA, 76107
| | - Ryan Rich
- Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center, 3500 Camp Bowie Blvd. Fort Worth, Texas, USA, 76107
| | - Zygmunt Gryczynski
- Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center, 3500 Camp Bowie Blvd. Fort Worth, Texas, USA, 76107
- Department of Physics. Texas Christian University, 2800 S. University Dr., Fort Worth, Texas, USA, 76129
| | - Ignacy Gryczynski
- Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center, 3500 Camp Bowie Blvd. Fort Worth, Texas, USA, 76107
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center. 3500 Camp Bowie Blvd. Fort Worth, Texas, USA, 76107
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Garlipp MA, Nowak KR, Gonzalez-Fernandez F. Cone outer segment extracellular matrix as binding domain for interphotoreceptor retinoid-binding protein. J Comp Neurol 2012; 520:756-69. [PMID: 21935947 DOI: 10.1002/cne.22773] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cones are critically dependent on interphotoreceptor retinoid-binding protein (IRBP) for retinoid delivery in the visual cycle. Cone-dominant vertebrates offer an opportunity to uncover the molecular basis of IRBP's role in this process. Here, we explore the association of IRBP with the interphotoreceptor matrix (IPM) of cones vs. rods in cone dominant retinas from chicken (Gallus domesticus), turkey (Meleagris gallopavo), and pig (Sus scrofa). Retinas were detached and fixed directly or washed in saline prior to fixation. Disassociated photoreceptors with adherent matrix were also prepared. Under 2 mM CaCl(2) , insoluble matrix was delaminated from saline washed retinas. The distribution of IRBP, as well as glycans binding peanut agglutinin (cone matrix) and wheat germ agglutinin (rod/cone matrix), was defined by confocal microscopy. Retina flat mounts showed IRBP diffusely distributed in an interconnecting, lattice-like pattern throughout the entire matrix. Saline wash replaced this pattern with fluorescent annuli surrounding individual cone outer segments. In isolated cones and matrix sheets, IRBP colocalized with the peanut agglutinin binding matrix glycans. Our results reveal a wash-resistant association of IRBP with a matrix domain immediately surrounding cone outer segments. The cone matrix sheath may be responsible for IRBP-mediated cone targeting of 11-cis retinoids.
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Affiliation(s)
- Mary Alice Garlipp
- Graduate Program in Neuroscience, School of Medicine and Biomedical Sciences, State University of New York, Buffalo, New York 14209, USA
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Ckurshumova W, Caragea AE, Goldstein RS, Berleth T. Glow in the dark: fluorescent proteins as cell and tissue-specific markers in plants. MOLECULAR PLANT 2011; 4:794-804. [PMID: 21772029 DOI: 10.1093/mp/ssr059] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Since the hallmark discovery of Aequorea victoria's Green Fluorescent Protein (GFP) and its adaptation for efficient use in plants, fluorescent protein tags marking expression profiles or genuine proteins of interest have been used to recognize plant tissues and cell types, to monitor dynamic cell fate selection processes, and to obtain cell type-specific transcriptomes. Fluorescent tagging enabled visualization in living tissues and the precise recordings of dynamic expression pattern changes. The resulting accurate recording of cell fate acquisition kinetics in space and time has strongly stimulated mathematical modeling of self-organizing feedback mechanisms. In developmental studies, the use of fluorescent proteins has become critical, where morphological markers of tissues, cell types, or differentiation stages are either not known or not easily recognizable. In this review, we focus on the use of fluorescent markers to identify and illuminate otherwise invisible cell states in plant development.
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Affiliation(s)
- Wenzislava Ckurshumova
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks St, Toronto, ON M5S 3B2, Canada.
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Matheu MP, Cahalan MD, Parker I. Immunoimaging: studying immune system dynamics using two-photon microscopy. Cold Spring Harb Protoc 2011; 2011:pdb.top99. [PMID: 21285279 DOI: 10.1101/pdb.top99] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
INTRODUCTIONCells of the immune system explore a wider territory than any other cells in the body. Responses to a pathogen typically require long-range migration of cells, short-range communication by local chemical signaling, and direct cell-cell contact. Two-photon microscopy allows these processes to be visualized within native tissue environments. Immunoimaging is rapidly developing from a merely descriptive technique into a set of methods and analytical tools that can be used to quantify and to characterize an immune response at the cellular level. This article outlines the hardware required for immunoimaging and discusses methods for quantitative analysis of multidimensional image stacks.
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Garner LE, Park J, Dyar SM, Chworos A, Sumner JJ, Bazan GC. Modification of the Optoelectronic Properties of Membranes via Insertion of Amphiphilic Phenylenevinylene Oligoelectrolytes. J Am Chem Soc 2010; 132:10042-52. [DOI: 10.1021/ja1016156] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Logan E. Garner
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, U.S. Army Research Laboratory, Sensors and Electron Devices Directorate, Adelphi, Maryland 20783, and School of Chemical Engineering and Materials Science, Chung-Ang University, 221 Heukseok-Dong, Dongjak-Gu, Seoul, Korea
| | - Juhyun Park
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, U.S. Army Research Laboratory, Sensors and Electron Devices Directorate, Adelphi, Maryland 20783, and School of Chemical Engineering and Materials Science, Chung-Ang University, 221 Heukseok-Dong, Dongjak-Gu, Seoul, Korea
| | - Scott M. Dyar
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, U.S. Army Research Laboratory, Sensors and Electron Devices Directorate, Adelphi, Maryland 20783, and School of Chemical Engineering and Materials Science, Chung-Ang University, 221 Heukseok-Dong, Dongjak-Gu, Seoul, Korea
| | - Arkadiusz Chworos
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, U.S. Army Research Laboratory, Sensors and Electron Devices Directorate, Adelphi, Maryland 20783, and School of Chemical Engineering and Materials Science, Chung-Ang University, 221 Heukseok-Dong, Dongjak-Gu, Seoul, Korea
| | - James J. Sumner
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, U.S. Army Research Laboratory, Sensors and Electron Devices Directorate, Adelphi, Maryland 20783, and School of Chemical Engineering and Materials Science, Chung-Ang University, 221 Heukseok-Dong, Dongjak-Gu, Seoul, Korea
| | - Guillermo C. Bazan
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, U.S. Army Research Laboratory, Sensors and Electron Devices Directorate, Adelphi, Maryland 20783, and School of Chemical Engineering and Materials Science, Chung-Ang University, 221 Heukseok-Dong, Dongjak-Gu, Seoul, Korea
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14
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La Schiazza O, Bille JF. High-speed two-photon excited autofluorescence imaging of ex vivo human retinal pigment epithelial cells toward age-related macular degeneration diagnostic. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:064008. [PMID: 19123655 DOI: 10.1117/1.2999607] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Age-related macular degeneration (AMD) is among the major concerns in ophthalmology, as it is the primary cause for irreversible blindness in developed countries. Nevertheless, there is poor understanding of the origins and mechanisms that trigger this important ocular disease. In common clinical pratice, AMD is monitored by autofluorescence imaging of the retinal pigment epithelial (RPE) cells through a confocal scanning laser ophthalmoscope. The RPE cells derive their dominant autofluorescence from the lipofuscin granules that accumulate in the cytoplasm with increasing age and disease. We explored a different approach to retinal RPE imaging using two-photon excited autofluorescence, offering intrinsic three-dimensional resolution, larger sensing depth and reduced photodamage compared to single-photon excited fluorescence ophthalmoscopy. A two-photon microscope, based on the architecture of a conventional scanning laser ophthalmoscope (HRT, Heidelberg Engineering, Germany), was designed for autofluorescence imaging on retina samples from postmortem human-donor eyes. We were able to visualize at video-rate speed single RPE lipofuscin granules, demonstrating the potential to develop this method toward clinical practice for patients with RPE-related retinal disease like AMD.
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Affiliation(s)
- Olivier La Schiazza
- University of Heidelberg, Kirchhoff Institute for Physics, Heidelberg, Germany.
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15
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Abstract
Confocal microscopes have evolved over the past 25 years from the early stage scanning systems to a collection of sophisticated laser scanning systems designed for a range of biomedical applications. Major improvements to the photon efficiency of the instrumentation coupled with the development of novel fluorescent reporters have enabled multidimensional imaging of living cells and tissues.
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Affiliation(s)
- Steve Paddock
- Howard Hughes Medical Institute, Department of Molecular Biology, University of Wisconsin, Madison, WI 53706, USA.
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16
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Yeh AT, Gibbs H, Hu JJ, Larson AM. Advances in Nonlinear Optical Microscopy for Visualizing Dynamic Tissue Properties in Culture. TISSUE ENGINEERING PART B-REVIEWS 2008; 14:119-31. [DOI: 10.1089/teb.2007.0284] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Alvin T. Yeh
- Department of Biomedical Engineering, Texas A & M University, College Staion, Texas
| | - Holly Gibbs
- Department of Biomedical Engineering, Texas A & M University, College Staion, Texas
| | - Jin-Jia Hu
- Department of Biomedical Engineering, Texas A & M University, College Staion, Texas
| | - Adam M. Larson
- Department of Biomedical Engineering, Texas A & M University, College Staion, Texas
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17
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Guehring T, Urban JP, Cui Z, Tirlapur UK. Noninvasive 3D vital imaging and characterization of notochordal cells of the intervertebral disc by femtosecond near-infrared two-photon laser scanning microscopy and spatial-volume rendering. Microsc Res Tech 2008; 71:298-304. [DOI: 10.1002/jemt.20557] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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18
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Kushner J, Kim D, So PTC, Blankschtein D, Langer RS. Dual-Channel Two-Photon Microscopy Study of Transdermal Transport in Skin Treated with Low-Frequency Ultrasound and a Chemical Enhancer. J Invest Dermatol 2007; 127:2832-46. [PMID: 17554365 DOI: 10.1038/sj.jid.5700908] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Visualization of transdermal permeant pathways is necessary to substantiate model-based conclusions drawn using permeability data. The aim of this investigation was to visualize the transdermal delivery of sulforhodamine B (SRB), a fluorescent hydrophilic permeant, and of rhodamine B hexyl ester (RBHE), a fluorescent hydrophobic permeant, using dual-channel two-photon microscopy (TPM) to better understand the transport pathways and the mechanisms of enhancement in skin treated with low-frequency ultrasound (US) and/or a chemical enhancer (sodium lauryl sulfate--SLS) relative to untreated skin (the control). The results demonstrate that (1) both SRB and RBHE penetrate beyond the stratum corneum and into the viable epidermis only in discrete regions (localized transport regions--LTRs) of US treated and of US/SLS-treated skin, (2) a chemical enhancer is required in the coupling medium during US treatment to obtain two significant levels of increased penetration of SRB and RBHE in US-treated skin relative to untreated skin, and (3) transcellular pathways are present in the LTRs of US treated and of US/SLS-treated skin for SRB and RBHE, and in SLS-treated skin for SRB. In summary, the skin is greatly perturbed in the LTRs of US treated and US/SLS-treated skin with chemical enhancers playing a significant role in US-mediated transdermal drug delivery.
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Affiliation(s)
- Joseph Kushner
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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19
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Davies ML, Kirov SA, Andrew RD. Whole isolated neocortical and hippocampal preparations and their use in imaging studies. J Neurosci Methods 2007; 166:203-16. [PMID: 17765319 PMCID: PMC2100436 DOI: 10.1016/j.jneumeth.2007.07.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Revised: 07/10/2007] [Accepted: 07/11/2007] [Indexed: 11/19/2022]
Abstract
This study shows that two whole isolated preparations from the young mouse, the neocortical 'slab' and the hippocampal formation, are useful for imaging studies requiring both global monitoring using light transmittance (LT) imaging and high resolution cellular monitoring using 2-photon laser scanning microscopy (2PLSM). These preparations share advantages with brain slices such as maintaining intrinsic neuronal properties and avoiding cardiac or respiratory movement. Important additional advantages include the maintenance of all local input and output pathways, the absence of surfaces injured by slicing and the preservation of three-dimensional tissue structure. Using evoked extracellular field recording, we demonstrate long-term (hours) viability of both whole preparations. We then show that propagating cortical events such as anoxic depolarization (AD) and spreading depression (SD) can be imaged in both preparations, yielding results comparable to those in brain slices but retaining the tissue's three-dimensional structure. Using transgenic mice expressing green fluorescent protein (GFP) in pyramidal and granule cell neurons, 2PLSM confirms that these preparations are free of the surface damage observed in sliced brain tissue. Moreover the neurons undergo swelling with accompanying dendritic beading following AD induced by simulated ischemia, similar to cortical damage described in vivo.
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Affiliation(s)
- Melissa L. Davies
- Department of Anatomy & Cell Biology and The Centre for Neuroscience Studies Queen’s University, Kingston, ON
| | - Sergei A. Kirov
- Department of Neurosurgery Medical College of Georgia, Augusta, GA
| | - R. David Andrew
- Department of Anatomy & Cell Biology and The Centre for Neuroscience Studies Queen’s University, Kingston, ON
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20
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Shi X, Basran J, Seward HE, Childs W, Bagshaw CR, Boxer SG. Anomalous negative fluorescence anisotropy in yellow fluorescent protein (YFP 10C): quantitative analysis of FRET in YFP dimers. Biochemistry 2007; 46:14403-17. [PMID: 18027983 DOI: 10.1021/bi701575n] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Yellow fluorescent protein (YFP) is widely used as a genetically encoded fluorescent marker in biology. In the course of a comprehensive study of this protein, we observed an unusual, negative fluorescence anisotropy at pH 6.0 (McAnaney, T. B., Zeng, W., Doe, C. F. E., Bhanji, N., Wakelin, S., Pearson, D. S., Abbyad, P., Shi, X., Boxer, S. G., and Bagshaw, C. R. (2005) Biochemistry 44, 5510-5524). Here we report that the fluorescence anisotropy of YFP 10C depends on protein concentration in the low micromolar range that was not expected. We propose that the negative anisotropy is a result of unidirectional Förster resonance energy transfer (FRET) in a dimer of YFP, with the donor chromophore in the neutral form and the acceptor chromophore in the anionic form. This unusual mechanism is supported by studies of a monomeric YFP (A206K YFP) and transient-absorption spectroscopy of YFP 10C. A detailed analysis of the chromophore transition dipole moment direction is presented. The anisotropy and rate constant of this energy transfer are consistent with values produced by an analysis of the dimer structure observed in crystals.
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Affiliation(s)
- Xinghua Shi
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA
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21
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Liu E, Treiser MD, Johnson PA, Patel P, Rege A, Kohn J, Moghe PV. Quantitative biorelevant profiling of material microstructure within 3D porous scaffolds via multiphoton fluorescence microscopy. J Biomed Mater Res B Appl Biomater 2007; 82:284-97. [PMID: 17238159 DOI: 10.1002/jbm.b.30732] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This study presents a novel approach, based on fluorescence multiphoton microscopy (MPM), to image and quantitatively characterize the microstructure and cell-substrate interactions within microporous scaffold substrates fabricated from synthetic biodegradable polymers. Using fluorescently dyed scaffolds fabricated from poly(DTE carbonate)/poly(DTO carbonate) blends of varying porosity and complementary green fluorescent protein-engineered fibroblasts, we reconstructed the three-dimensional distribution of the microporous and macroporous regions in 3D scaffolds, as well as cellular morphological patterns. The porosity, pore size and distribution, strut size, pore interconnectivity, and orientation of both macroscale and microscale pores of 3D scaffolds were effectively quantified and validated using complementary imaging techniques. Compared to other scaffold characterizing techniques such as confocal imaging and scanning electron microscopy (SEM), MPM enables the acquisition of images from scaffold thicknesses greater than a hundred microns with high signal-to-noise ratio, reduced bulk photobleaching, and the elimination of the need for deconvolution. In our study, the morphology and cytoskeletal organization of cells within the scaffold interior could be tracked with high resolution within the limits of penetration of MPM. Thus, MPM affords a promising integrated platform for imaging cell-material interactions within the interior of polymeric biomaterials.
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Affiliation(s)
- Er Liu
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey 08854, USA
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22
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Hughes D, Tirlapur UK, Field R, Cui Z. In situ 3D characterization of membrane fouling by yeast suspensions using two-photon femtosecond near infrared non-linear optical imaging. J Memb Sci 2006. [DOI: 10.1016/j.memsci.2006.01.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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23
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Tirlapur UK, Mulholland WJ, Bellhouse BJ, Kendall M, Cornhill JF, Cui Z. Femtosecond two-photon high-resolution 3D imaging, spatial-volume rendering and microspectral characterization of immunolocalized MHC-II and mLangerin/CD207 antigens in the mouse epidermis. Microsc Res Tech 2006; 69:767-75. [PMID: 16941665 DOI: 10.1002/jemt.20331] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Langerhans cells (LCs) play a sentinel role by initiating both adaptive and innate immune responses to antigens pertinent to the skin. With the discovery of various LCs markers including antibodies to major histocompatibility complex class II (MHC-II) molecules and CD1a, intracellular presence of racket-shaped "Birbeck granules," and very recently Langerin/CD207, LCs can be readily distinguished from other subsets of dendritic cells. Femtosecond two-photon laser scanning microscopy (TPLSM) in recent years has emerged as an alternative to the single photon-excitation based confocal laser scanning microscope (CLSM), particularly for minimally-invasive deep-tissue 3D and 4D vital as well as nonvital biomedical imaging. We have recently combined high resolution two-photon immunofluorescence (using anti MHC-II and Langerin/CD207 antibodies) imaging with microspectroscopy and advanced image-processing/volume-rendering modalities. In this work, we demonstrate the use of this novel state-of-the-art combinational approach to characterize the steady state 3D organization and spectral features of the mouse epidermis, particularly to identify the spatial distribution of LCs. Our findings provide unequivocal direct evidence that, in the mouse epidermis, the MHC-II and mLangerin/CD207 antigens do indeed manifest a high degree of colocalization around the nucleus of the LCs, while in the distal dendritic processes, mLangerin/CD207 antigens are rather sparsely distributed as punctuate structures. This unique possibility to simultaneously visualize high resolution 3D-resolved spatial distributions of two different immuno-reactive antigens, namely MHC-II and mLangerin/CD207, along with the nuclei of LCs and the adjacent epidermal cells can find interesting applications. These could involve aspects associated with pragmatic analysis of the kinetics of LCs migration as a function of immuno-dermatological responses during (1) human Immunodeficiency virus disease progression, (2) vaccination and targeted gene therapy, (3) skin transplantation/plastic surgery, (4) ultraviolet and other radiation exposure, (5) tissue-engineering of 3D skin constructs, as well as in (6) cosmetic industry, to unravel the influence of cosmeceuticals.
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Affiliation(s)
- Uday K Tirlapur
- Department of Engineering Science, Oxford Institute of Biomedical Engineering, University of Oxford, Oxford OX1 3PJ, United Kingdom.
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24
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Hu Z, Hidalgo G, Houston PL, Hay AG, Shuler ML, Abruña HD, Ghiorse WC, Lion LW. Determination of spatial distributions of zinc and active biomass in microbial biofilms by two-photon laser scanning microscopy. Appl Environ Microbiol 2005; 71:4014-21. [PMID: 16000816 PMCID: PMC1168982 DOI: 10.1128/aem.71.7.4014-4021.2005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The spatial distributions of zinc, a representative transition metal, and active biomass in bacterial biofilms were determined using two-photon laser scanning microscopy (2P-LSM). Application of 2P-LSM permits analysis of thicker biofilms than are amenable to observation with confocal laser scanning microscopy and also provides selective excitation of a smaller focal volume with greater depth localization. Thin Escherichia coli PHL628 biofilms were grown in a minimal mineral salts medium using pyruvate as the carbon and energy source under batch conditions, and thick biofilms were grown in Luria-Bertani medium using a continuous-flow drip system. The biofilms were visualized by 2P-LSM and shown to have heterogeneous structures with dispersed dense cell clusters, rough surfaces, and void spaces. Contrary to homogeneous biofilm model predictions that active biomass would be located predominantly in the outer regions of the biofilm and inactive or dead biomass (biomass debris) in the inner regions, significant active biomass fractions were observed at all depths in biofilms (up to 350 microm) using live/dead fluorescent stains. The active fractions were dependent on biofilm thickness and are attributed to the heterogeneous characteristics of biofilm structures. A zinc-binding fluorochrome (8-hydroxy-5-dimethylsulfoamidoquinoline) was synthesized and used to visualize the spatial location of added Zn within biofilms. Zn was distributed evenly in a thin (12 microm) biofilm but was located only at the surface of thick biofilms, penetrating less than 20 microm after 1 h of exposure. The relatively slow movement of Zn into deeper biofilm layers provides direct evidence in support of the concept that thick biofilms may confer resistance to toxic metal species by binding metals at the biofilm-bulk liquid interface, thereby retarding metal diffusion into the biofilm (G. M. Teitzel and M. R. Park, Appl. Environ. Microbiol. 69:2313-2320, 2003).
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Affiliation(s)
- Zhiqiang Hu
- School of Civil and Environmental Engineering, Cornell University, Hollister Hall, Ithaca, NY 14853, USA
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25
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Abstract
Two-photon excitation fluorescence imaging provides thin optical sections from deep within thick, scattering specimens by way of restricting fluorophore excitation (and thus emission) to the focal plane of the microscope. Spatial confinement of two-photon excitation gives rise to several advantages over single-photon confocal microscopy. First, penetration depth of the excitation beam is increased. Second, because out-of-focus fluorescence is never generated, no pinhole is necessary in the detection path of the microscope, resulting in increased fluorescence collection efficiency. Third, two-photon excitation markedly reduces overall photobleaching and photodamage, resulting in extended viability of biological specimens during long-term imaging. Finally, localized excitation can be used for photolysis of caged compounds in femtoliter volumes and for diffusion measurements by two-photon fluorescence photobleaching recovery. This review aims to provide an overview of the use of two-photon excitation microscopy. Selected applications of this technique will illustrate its excellent suitability to assess cellular and subcellular events in intact, strongly scattering tissue. In particular, its capability to resolve differences in calcium dynamics between individual cardiomyocytes deep within intact, buffer-perfused hearts is demonstrated. Potential applications of two-photon laser scanning microscopy as applied to integrative cardiac physiology are pointed out.
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Affiliation(s)
- Michael Rubart
- Herman B Wells Center for Pediatric Research and Krannert Institute of Cardiology, Indiana University School of Medicine, 1044 W Walnut St, Rm W359, Indianapolis, IN 46202-5225, USA.
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26
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MILLS JAMESD, STONE JAMESR, OKONKWO DAVIDO, PERIASAMY AMMASI, HELM GREGORYA. Multiphoton FRET Microscopy for Protein Localization in Tissue. Mol Imaging 2005. [DOI: 10.1016/b978-019517720-6.50015-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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27
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Pentecost JO, Silva C, Pesticelli M, Thornburg KL. Modeling cardiogenesis: the challenges and promises of 3D reconstruction. Curr Top Dev Biol 2004; 56:115-43. [PMID: 14584728 DOI: 10.1016/s0070-2153(03)01009-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Affiliation(s)
- Jeffrey O Pentecost
- Department of Medical Informatics and Outcomes Research, Oregon Health and Science University, Portland, Oregon 97201, USA
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28
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Neu TR, Lawrence JR. One-photon versus Two-photon Laser Scanning Mic roscopy and Digital Image Analysis of Microbial Biofilms. J Microbiol Methods 2004. [DOI: 10.1016/s0580-9517(04)34004-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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29
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Abstract
Interacting proteins assemble into molecular machines that control cellular homeostasis in living cells. While the in vitro screening methods have the advantage of providing direct access to the genetic information encoding unknown protein partners, they do not allow direct access to interactions of these protein partners in their natural environment inside the living cell. Using wide-field, confocal, or two-photon (2p) fluorescence resonance energy transfer (FRET) microscopy, this information can be obtained from living cells and tissues with nanometer resolution. One of the important conditions for FRET to occur is the overlap of the emission spectrum of the donor with the absorption spectrum of the acceptor. As a result of spectral overlap, the FRET signal is always contaminated by donor emission into the acceptor channel and by the excitation of acceptor molecules by the donor excitation wavelength. Mathematical algorithms are required to correct the spectral bleed-through signal in wide-field, confocal, and two-photon FRET microscopy. In contrast, spectral bleed-through is not an issue in FRET/FLIM imaging because only the donor fluorophore lifetime is measured; also, fluorescence lifetime imaging microscopy (FLIM) measurements are independent of excitation intensity or fluorophore concentration. The combination of FRET and FLIM provides high spatial (nanometer) and temporal (nanosecond) resolution when compared to intensity-based FRET imaging. In this paper, we describe various FRET microscopy techniques and its application to protein-protein interactions.
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Affiliation(s)
- Ye Chen
- W.M. Keck Center for Cellular Imaging University of Virginia Charlottesville, VA 22904, USA
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30
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Zipfel WR, Williams RM, Webb WW. Nonlinear magic: multiphoton microscopy in the biosciences. Nat Biotechnol 2003; 21:1369-77. [PMID: 14595365 DOI: 10.1038/nbt899] [Citation(s) in RCA: 2202] [Impact Index Per Article: 104.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Multiphoton microscopy (MPM) has found a niche in the world of biological imaging as the best noninvasive means of fluorescence microscopy in tissue explants and living animals. Coupled with transgenic mouse models of disease and 'smart' genetically encoded fluorescent indicators, its use is now increasing exponentially. Properly applied, it is capable of measuring calcium transients 500 microm deep in a mouse brain, or quantifying blood flow by imaging shadows of blood cells as they race through capillaries. With the multitude of possibilities afforded by variations of nonlinear optics and localized photochemistry, it is possible to image collagen fibrils directly within tissue through nonlinear scattering, or release caged compounds in sub-femtoliter volumes.
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MESH Headings
- Biological Science Disciplines/instrumentation
- Biological Science Disciplines/methods
- Biological Science Disciplines/trends
- Equipment Design
- Image Enhancement/instrumentation
- Image Enhancement/methods
- Imaging, Three-Dimensional/instrumentation
- Imaging, Three-Dimensional/methods
- Imaging, Three-Dimensional/trends
- Microscopy, Confocal/instrumentation
- Microscopy, Confocal/methods
- Microscopy, Confocal/trends
- Microscopy, Fluorescence, Multiphoton/instrumentation
- Microscopy, Fluorescence, Multiphoton/methods
- Microscopy, Fluorescence, Multiphoton/trends
- Nonlinear Dynamics
- Transducers
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Affiliation(s)
- Warren R Zipfel
- School of Applied and Engineering Physics, 212 Clark Hall, Cornell University, Ithaca, New York 14853, USA
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31
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Mills JD, Stone JR, Rubin DG, Melon DE, Okonkwo DO, Periasamy A, Helm GA. Illuminating protein interactions in tissue using confocal and two-photon excitation fluorescent resonance energy transfer microscopy. JOURNAL OF BIOMEDICAL OPTICS 2003; 8:347-356. [PMID: 12880338 DOI: 10.1117/1.1584443] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Traumatic brain injury (TBI) remains the most common cause of death in persons under age 45 in the Western world. One of the principal determinants of morbidity and mortality following TBI is traumatic axonal injury (TAI). Current hypotheses on the pathogenesis of TAI involve activation of apoptotic cascades secondary to TBI. While a number of studies have demonstrated direct evidence for the activation of apoptotic cascades in TAI, the precise pathway by which these cascades are initiated remains a subject of intense investigation. As axolemmal disruption with the subsequent intra-axonal influx of large molecular weight species has been demonstrated to occur in relation to local axonal breakdown, attention has focused on cascades that may occur as a result of loss of ionic homeostasis. One proposed pathway by which this has been hypothesized to occur is the Ca(2+)-mediated activation of calmodulin and subsequent activation of the phosphatase calcineurin with dephosphorylation of a protein known as BAD, leading to a proapoptotic interaction between BAD and the mitochondrial protein Bcl-xL. While this pathway is an intriguing route for traumatic axonal pathogenesis, neither conventional immunocytochemical/histochemical nor ultrastructural approaches have had the capacity to shed insight on whether BAD and Bcl-xL interact in TAI in vivo. We describe the implementation of confocal and two-photon excitation fluorescence resonance energy transfer (FRET) microscopy techniques through which we demonstrate interaction between the proapoptotic protein BAD and the prosurvival protein Bcl-xL within TAI following TBI. Further, we report on a method to reliably detect protein interactions within aldehyde fixed tissue sections through conventional immunohistochemical approaches.
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Affiliation(s)
- James D Mills
- University of Virginia Health Sciences Center, Department of Neurosurgery, Charlottesville, Virginia 22908, USA
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32
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Affiliation(s)
- Victoria E Centonze
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900, USA
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33
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Benham GS. Practical aspects of objective lens selection for confocal and multiphoton digital imaging techniques. Methods Cell Biol 2003; 70:245-99. [PMID: 12512326 DOI: 10.1016/s0091-679x(02)70007-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
MESH Headings
- Animals
- Humans
- Image Processing, Computer-Assisted/instrumentation
- Image Processing, Computer-Assisted/methods
- Image Processing, Computer-Assisted/standards
- Lenses/standards
- Microscopy, Confocal/instrumentation
- Microscopy, Confocal/methods
- Microscopy, Confocal/standards
- Microscopy, Fluorescence, Multiphoton/instrumentation
- Microscopy, Fluorescence, Multiphoton/methods
- Microscopy, Fluorescence, Multiphoton/standards
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Affiliation(s)
- Gerald S Benham
- BioScience Confocal Systems, Nikon Instruments Inc., Melville, New York 11747, USA
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34
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Affiliation(s)
- James E N Jonkman
- Advanced Optical Microscopy Facility, Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Canada
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35
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Affiliation(s)
- Timothy M Ragan
- Department of Mechanical Engineering, Division of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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36
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Chen Y, Periasamy A. Characterization of two-photon excitation fluorescence lifetime imaging microscopy for protein localization. Microsc Res Tech 2003; 63:72-80. [PMID: 14677136 DOI: 10.1002/jemt.10430] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Two-photon excitation fluorescence resonance energy transfer (2P-FRET) imaging microscopy can provide details of specific protein molecule interactions inside living cells. Fluorophore molecules used for 2P-FRET imaging have characteristic absorption and emission spectra that introduce spectral cross-talk (bleed-through) in the FRET signal that should be removed in the 2P-FRET images, to establish that FRET has actually occurred and to have a basis for distance estimations. These contaminations in the FRET signal can be corrected using a mathematical algorithm to extract the true FRET signal. Another approach is 2P-FRET fluorescence lifetime imaging (FLIM). This methodology allows studying the dynamic behavior of protein-protein interactions in living cells and tissues. 2P-FRET-FLIM was used to study the dimerization of the CAATT/enhancer binding protein alpha (C/EBPalpha). Results show that the reduction in donor lifetime in the presence of acceptor reveals the dimerization of the protein molecules and also determines more precisely the distance between the donor and acceptor. We describe the development and characterization of the 2P-FRET-FLIM imaging system with the Bio-Rad Radiance2100 confocal/multiphoton microscopy system.
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Affiliation(s)
- Ye Chen
- W.M. Keck Center for Cellular Imaging, University of Virginia, Charlottesville, Virginia 22904, USA
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37
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Elangovan M, Wallrabe H, Chen Y, Day RN, Barroso M, Periasamy A. Characterization of one- and two-photon excitation fluorescence resonance energy transfer microscopy. Methods 2003; 29:58-73. [PMID: 12543072 DOI: 10.1016/s1046-2023(02)00283-9] [Citation(s) in RCA: 175] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Advances in molecular biology provide various methods to define the structure and function of the individual proteins that form the component parts of subcellular structures. The ability to see the dynamic behavior of a specific protein inside the living cell became possible through the application of advanced fluorescence resonance energy transfer (FRET) microscope techniques. The fluorophore molecule used for FRET imaging has a characteristic absorption and emission spectrum that should be considered for characterizing the FRET signal. In this article we describe the system development for the image acquisition for one- and two-photon excitation FRET microscopy. We also describe the precision FRET (PFRET) data analysis algorithm that we developed to remove spectral bleed-through and variation in the fluorophore expression level (or concentration) for the donor and acceptor molecules. The acquired images have been processed using a PFRET algorithm to calculate the energy transfer efficiency and the distance between donor and acceptor molecules. We implemented the software correction to study the organization of the apical endosome in epithelial polarized MDCK cells and dimerization of the CAATT/enhancer binding protein alpha (C/EBPalpha). For these proteins, the results revealed that the extent of correction affects the conventionally calculated energy transfer efficiency (E) and the distance (r) between donor and acceptor molecules by 38 and 9%, respectively.
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Affiliation(s)
- Masilamani Elangovan
- W.M. Keck Center for Cellular Imaging, Gilmer Hall, 22904, Charlottesville, VA, USA
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38
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Yu YA, Szalay AA, Wang G, Oberg K. Visualization of molecular and cellular events with green fluorescent proteins in developing embryos: a review. LUMINESCENCE 2003; 18:1-18. [PMID: 12536374 DOI: 10.1002/bio.701] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
During the past 5 years, green fluorescent protein (GFP) has become one of the most widely used in vivo protein markers for studying a number of different molecular processes during development, such as promoter activation, gene expression, protein trafficking and cell lineage determination. GFP fluorescence allows observation of dynamic developmental processes in real time, in both transiently and stably transformed cells, as well as in live embryos. In this review, we include the most up-to-date use of GFP during embryonic development and point out the unique contribution of GFP visualization, which resulted in novel discoveries.
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Affiliation(s)
- Yong A Yu
- Division of Biochemistry, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
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Two-photon excitation microscopy. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1076-5670(03)80016-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Gale JE, Meyers JR, Periasamy A, Corwin JT. Survival of bundleless hair cells and subsequent bundle replacement in the bullfrog's saccule. JOURNAL OF NEUROBIOLOGY 2002; 50:81-92. [PMID: 11793356 DOI: 10.1002/neu.10002] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Our senses of hearing and balance depend upon hair cells, the sensory receptors of the inner ear. Millions of people suffer from hearing and balance deficits caused by damage to hair cells as a result of exposure to noise, aminoglycoside antibiotics, and antitumor drugs. In some species such damage can be reversed through the production of new cells. This proliferative response is limited in mammals but it has been hypothesized that damaged hair cells might survive and undergo intracellular repair. We examined the fate of bullfrog saccular hair cells after exposure to a low dose of the aminoglycoside antibiotic gentamicin to determine whether hair cells could survive such treatment and subsequently be repaired. In organ cultures of the bullfrog saccule a combination of time-lapse video microscopy, two-photon microscopy, electron microscopy, and immunocytochemistry showed that hair cells can lose their hair bundle and survive as bundleless cells for at least 1 week. Time-lapse and electron microscopy revealed stages in the separation of the bundle from the cell body. Scanning electron microscopy (SEM) of cultures fixed 2, 4, and 7 days after antibiotic treatment showed that numerous new hair bundles were produced between 4 and 7 days of culture. Further examination revealed hair cells with small repaired hair bundles alongside damaged remnants of larger surviving bundles. The results indicate that sensory hair cells can undergo intracellular self-repair in the absence of mitosis, offering new possibilities for functional hair cell recovery and an explanation for non-proliferative recovery.
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Affiliation(s)
- Jonathan E Gale
- Department of Otolaryngology, HNS, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.
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Affiliation(s)
- J D Bryers
- Center for Biomaterials, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
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Yu B, Dong CY, So PT, Blankschtein D, Langer R. In vitro visualization and quantification of oleic acid induced changes in transdermal transport using two-photon fluorescence microscopy. J Invest Dermatol 2001; 117:16-25. [PMID: 11442745 DOI: 10.1046/j.0022-202x.2001.01353.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In a novel application of two-photon scanning fluorescence microscopy, three-dimensional spatial distributions of the hydrophilic and hydrophobic fluorescent probes, sulforhodamine B and rhodamine B hexyl ester, in excised full-thickness human cadaver skin were visualized and quantified. Both sulforhodamine B and rhodamine B hexyl ester were observed to lie primarily in the lipid multilamellae region surrounding the corneocytes within the stratum corneum. From the two-photon scanning fluorescence microscopy scans, the changes in the concentration gradient and the vehicle to skin partition coefficient of each probe induced by the oleic acid enhancer action were calculated relative to the control sample (not exposed to oleic acid), and subsequently applied to theoretically derived mathematical expressions of transdermal transport to quantitatively characterize the oleic acid-induced relative changes in the skin diffusion coefficient and the skin barrier diffusion length of the permeant. For the hydrophobic probe rhodamine B hexyl ester, the permeability enhancement was primarily driven by an increase in the vehicle to skin partition coefficient, leading to an increase in the steepness of the concentration gradient across the skin. The primary oleic acid-induced changes in the transport properties of the hydrophilic probe sulforhodamine B included increases in the vehicle to skin partition coefficient and the skin diffusion coefficient. These findings utilizing the two-photon scanning fluorescence microscopy methodology and data analysis described here demonstrate that, in addition to providing three-dimensional images that clearly delineate probe distributions in the direction of increasing skin depth, the subsequent quantification of these images provides additional important insight into the mechanistic changes in transdermal transport underlying the visualized changes in probe distributions across the skin.
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Affiliation(s)
- B Yu
- Departments of Chemical Engineering and Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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Periasamy A. Fluorescence resonance energy transfer microscopy: a mini review. JOURNAL OF BIOMEDICAL OPTICS 2001; 6:287-291. [PMID: 11516318 DOI: 10.1117/1.1383063] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2001] [Accepted: 04/03/2001] [Indexed: 05/23/2023]
Abstract
Fluorescence resonance energy transfer (FRET) microscopy is a better method than the x-ray diffraction, nuclear magnetic resonance, or electron microscopy for studying the structure and localization of proteins under physiological conditions. In this paper, we describe four different light microscopy techniques to visualize the interactions of the transcription factor CAATT/enhancer binding protein alpha (C/EBPalpha) in living pituitary cells. In wide-field, confocal, and two-photon microscopy the FRET image provides two-dimensional spatial distribution of steady-state protein-protein interactions. The two-photon imaging technique provides a better FRET signal (less bleedthrough and photobleaching) compared to the other two techniques. This information, although valuable, falls short of revealing transient interactions of proteins in real time. The fluorescence lifetime methods allow us to monitor FRET signals at the moment of the protein interactions at a resolution on the order of subnanoseconds, providing high temporal, as well as spatial resolution. This paper will provide a brief review of the above-mentioned FRET techniques.
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Affiliation(s)
- A Periasamy
- University of Virginia, W. M. Keck Center for Cellular Imaging, Department of Biology, Gilmer Hall, Charlottesville, Virginia 22904, USA.
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Diaspro A, Chirico G, Federici F, Cannone F, Beretta S, Robello M. Two-photon microscopy and spectroscopy based on a compact confocal scanning head. JOURNAL OF BIOMEDICAL OPTICS 2001; 6:300-310. [PMID: 11516320 DOI: 10.1117/1.1382809] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2001] [Revised: 03/24/2001] [Accepted: 04/11/2001] [Indexed: 05/23/2023]
Abstract
We have combined a confocal laser scanning head modified for TPE (two-photon excitation) microscopy with some spectroscopic modules to study single molecules and molecular aggregates. The behavior of the TPE microscope unit has been characterized by means of point spread function measurements and of the demonstration of its micropatterning abilities. One-photon and two-photon mode can be simply accomplished by switching from a mono-mode optical fiber (one-photon) coupled to conventional laser sources to an optical module that allows IR laser beam (two-photon/TPE) delivery to the confocal laser scanning head. We have then described the characterization of the two-photon microscope for spectroscopic applications: fluorescence correlation, lifetime and fluorescence polarization anisotropy measurements. We describe the measurement of the response of the two-photon microscope to the light polarization and discuss fluorescence polarization anisotropy measurements on Rhodamine 6G as a function of the viscosity and on a globular protein, the Beta-lactoglobulin B labeled with Alexa 532 at very high dilutions. The average rotational and translational diffusion coefficients measured with fluorescence polarization anisotropy and fluorescence correlation methods are in good agreement with the protein size, therefore validating the use of the microscope for two-photon spectroscopy on biomolecules.
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Affiliation(s)
- A Diaspro
- University of Genoa, National Institute for the Physics of Matter (INFM), Department of Physics, Via Dodecaneso 33, 16146 Genova, Italy.
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Tirlapur UK, König K, Peuckert C, Krieg R, Halbhuber KJ. Femtosecond near-infrared laser pulses elicit generation of reactive oxygen species in mammalian cells leading to apoptosis-like death. Exp Cell Res 2001; 263:88-97. [PMID: 11161708 DOI: 10.1006/excr.2000.5082] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Two-photon excitation-based near-infrared (NIR) laser scanning microscopy is currently emerging as a new and versatile alternative to conventional confocal laser scanning microscopy, particularly for vital cell imaging in life sciences. Although this innovative microscopy has several advantages such as highly localized excitation, higher penetration depth, reduced photobleaching and photodamage, and improved signal to noise ratio, it has, however, recently been evidenced that high-power NIR laser irradiation can drastically inhibit cell division and induce cell death. In the present study we have investigated the cellular responses of unlabeled rat kangaroo kidney epithelium (PtK2) cells to NIR femtosecond laser irradiation. We demonstrate that NIR 170-fs laser pulses operating at 80-MHz pulse repetition frequency and at mean power of > or = 7 mW evoke generation of reactive oxygen species (ROS) such as H2O2 that can be visualized in situ by standard in vivo cytochemical analysis using Ni-3,3'-diaminobenzidine (Ni-DAB) as well as with a recently developed fluorescent probe Jenchrom px blue. The formation of the Ni-DAB reaction product as well as that of Jenchrom was relatively more pronounced when irradiated cells were incubated in alkaline solution (pH 8) than in those incubated in acidic solution (pH 6), suggesting peroxisomal localization of these reaction products. Two-photon time-lapse imaging of the internalization of the cell impermeate fluorescent dye propidium iodide revealed that the integrity of the plasma membrane of NIR irradiated cells is drastically compromised. Visualization of the nuclei with DNA-specific fluorescent probes such as 4',6-diamidino-2-phenylindole 24 h postirradiation further provided tangible evidence that the nuclei of these cells undergo several deformations and eventual fragmentation. That these NIR irradiated cells die by apoptosis has been established by in situ detection of DNA strand breaks using the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling method. Because the reactive oxygen species such as H2O2 and OH* can cause noxious effects such as cell membrane injury by peroxidation of polyunsaturated lipids and proteins and oxidative phosphorylation, and alterations of ATP-dependent Ca2+ pumps, these ROS are likely to contribute to drastic cytological alterations observed in this study following NIR irradiation. Taken together, we have established that NIR laser irradiations at mean power > or = 7 mW delivered at pulse duration time of 170 fs generally used in two- and multiphoton microscopes cause oxidative stress (1) evoking production of ROS, (2) resulting in membrane barrier dysfunction, (3) inducing structural deformations and fragmentation of the nuclei as well as DNA strand breaks, (4) leading to cell death by apoptosis.
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Affiliation(s)
- U K Tirlapur
- Laser Microscopy Division, Institute of Anatomy II, Friedrich Schiller University Jena, Teichgraben 7, Jena, D-07743, Germany.
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Diaspro A, Robello M. Two-photon excitation of fluorescence for three-dimensional optical imaging of biological structures. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2000; 55:1-8. [PMID: 10877060 DOI: 10.1016/s1011-1344(00)00028-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Techniques based on two-photon excitation (TPE) allow three-dimensional (3D) imaging in highly localized volumes, of the order of magnitude of a fraction of a femtolitre up to single-molecule detection. In TPE microscopy a fundamental advantage over conventional widefield or confocal 3D fluorescence microscopy is given by the use of infrared (IR) instead of ultraviolet (UV) radiation to excite those fluorophores requiring UV excitation, hence causing little damage to the specimen or to fluorescent molecules outside the volume of the TPE event and allowing a deeper penetration within the sample compared with conventional one-photon excitation of fluorescence. In our laboratory, within the framework of a national INFM project, we have realized a TPE fluorescence microscope, part of a multipurpose architecture also including lifetime imaging and fluorescence correlation spectroscopy modules. The core of the architecture is a mode-locked Ti:sapphire infrared pulsed laser pumped by a high-power (5 W, 532 nm) solid-state laser and coupled to an ultracompact scanning head. For the source we have measured a pulse width from 65 to 95 fs as a function of wavelength (690-830 nm). The scanning head allows conventional and two-photon confocal imaging. Point spread function measurements are reported with examples of applications to the study of biological systems.
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Affiliation(s)
- A Diaspro
- INFM and Department of Physics, University of Genoa, Italy.
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Affiliation(s)
- A Diaspro
- INFM and Department of Physics, University of Genoa, Italy
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