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Kemoklidze KG, Tyumina NA. 3D organization of the rat adrenal medulla. VITAMINS AND HORMONES 2023; 124:367-392. [PMID: 38408803 DOI: 10.1016/bs.vh.2023.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Without knowledge of the spatial [three-dimensional, (3D)] organization of an organ at the tissue and cellular levels, it is impossible to form a complete picture of its structure and function. At the same time, tissue components hidden in the thickness of the organ are the most difficult to study. The rapid development of computer technologies has contributed both to the development and implementation of new methods for studying 3D microstructures of organs, and the improvement of classical ones but the most complete picture can still be obtained only by recreating 3D models from serial histological sections. This fully applies to the important, but hidden in the thickness of the organ, and difficult to study 3D organization of the adrenal medulla. Only 3D reconstruction from serial sections makes it possible to identify all the main tissue components of the adrenal medulla simultaneously and with good resolution. Of particular importance to this method is the ability to reliably differentiate and study separately the 3D organization of the two main subpopulations of medulla endocrinocytes: adrenaline-storing (A-) cells and noradrenaline-storing (NA-) cells. In this chapter, we discuss the 3D organization of the adrenal medulla based on these original serial section 3D reconstructions and correlating them with data obtained by other methods.
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Affiliation(s)
- K G Kemoklidze
- Department of Histology, Cytology and Embryology, Yaroslavl State Medical University, Yaroslavl, Russia.
| | - N A Tyumina
- Department of Histology, Cytology and Embryology, Yaroslavl State Medical University, Yaroslavl, Russia
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2
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Kemoklidze KG, Tyumina NA, Leonenko PS. 3D reconstruction of the rat adrenal medulla. Anat Histol Embryol 2021; 50:781-787. [PMID: 34145614 DOI: 10.1111/ahe.12720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/21/2021] [Accepted: 06/03/2021] [Indexed: 11/29/2022]
Abstract
We performed 3D reconstruction of the microscopic structure of the adrenal medulla of the adult rats using serial histological sections with histochemical differentiation of adrenaline-storing (A) and noradrenaline-storing (NA) cells. Medulla volume is 1.18 ± 0.17 mm3 . Chromaffin tissue consists of 82.9 ± 2.6% of A and 17.1 ± 2.6% of NA cells. Cords of the chromaffinocytes run along the nerves in the adrenal cortex and form cones when merging with medulla bulk. There is no unambiguously greater prevalence of A cells over NA in the areas of the medulla bordering on the cortex as compared to deep layers of medulla. NA cells form a network of beams. Their concentration increases with distance from the entry site of the nerves and is maximal on the opposite side. This testifies to the fallacy of the point of view about the disordered distribution of NA cells in the medulla. Based on the polar asymmetric arrangement of the adrenal chromaffin tissue, if it is necessary to completely remove the medulla with the keeping or reimplantation of the cortex, the subcapsular cortex zone located on the pole opposite to the entrance of nerves should be chosen. In addition, comparable results in the stereological examination of the medulla can be obtained only if taking its areas similar in location. The pronounced relationship in the arrangement of A and NA cells with nerves clearly indicates that in vivo nerve factors play a key role in differentiation and stabilization of the A and NA cells phenotypes.
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Affiliation(s)
| | - Natalia Andreevna Tyumina
- Department of Histology, Cytology and Embryology, Yaroslavl State Medical University, Yaroslavl, Russia
| | - Pavel Sergeevich Leonenko
- Department of Histology, Cytology and Embryology, Yaroslavl State Medical University, Yaroslavl, Russia
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Kuriu S, Kadonosono T, Kizaka-Kondoh S, Ishida T. Slicing Spheroids in Microfluidic Devices for Morphological and Immunohistochemical Analysis. MICROMACHINES 2020; 11:mi11050480. [PMID: 32384758 PMCID: PMC7281316 DOI: 10.3390/mi11050480] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/02/2020] [Accepted: 05/04/2020] [Indexed: 02/06/2023]
Abstract
Microfluidic devices utilizing spheroids play important roles in in vitro experimental systems to closely simulate morphological and biochemical characteristics of the in vivo tumor microenvironment. For the observation and analysis of the inner structure of spheroids, sectioning is an efficient approach. However, conventional microfluidic devices are difficult for sectioning, and therefore, spheroids inside the microfluidic channels have not been sliced well. We proposed a microfluidic device created from embedding resin for sectioning. Spheroids were cultured, embedded by resin, and sectioned in the microfluidic device. Slices of the sectioned spheroids yielded clear images at the cellular level. According to morphological and immunohistochemical analyses of the slices of the spheroid, specific protein distribution was observed.
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Affiliation(s)
- Satoru Kuriu
- Department of Mechanical Engineering, School of Engineering, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
- Correspondence: (S.K.); (T.I.)
| | - Tetsuya Kadonosono
- Department of Life Science and Technology, School of Life Science and Technology, Tokyo Institute of Technology, Kanagawa 226-8503, Japan; (T.K.); (S.K.-K.)
| | - Shinae Kizaka-Kondoh
- Department of Life Science and Technology, School of Life Science and Technology, Tokyo Institute of Technology, Kanagawa 226-8503, Japan; (T.K.); (S.K.-K.)
| | - Tadashi Ishida
- Department of Mechanical Engineering, School of Engineering, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
- Correspondence: (S.K.); (T.I.)
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4
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Iandolo D, Pennacchio FA, Mollo V, Rossi D, Dannhauser D, Cui B, Owens RM, Santoro F. Electron Microscopy for 3D Scaffolds-Cell Biointerface Characterization. ACTA ACUST UNITED AC 2018; 3:e1800103. [PMID: 32627375 DOI: 10.1002/adbi.201800103] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 08/31/2018] [Indexed: 12/18/2022]
Abstract
Cell fate is largely determined by interactions that occur at the interface between cells and their surrounding microenvironment. For this reason, especially in the field of tissue-engineering, there is a growing interest in developing techniques that allow evaluating cell-material interaction at the nanoscale, particularly focusing on cell adhesion processes. While for 2D culturing systems a consolidated series of tools already satisfy this need, in 3D environments, more closely recapitulating complex in vivo structures, there is still a lack of procedures furthering the comprehension of cell-material interactions. Here, the use of scanning electron microscopy coupled with a focused ion beam (SEM/FIB) for the characterization of cell interactions with 3D scaffolds obtained by different fabrication techniques is reported for the first time. The results clearly show the capability of the developed approach to preserve and finely resolve scaffold-cell interfaces highlighting details such as plasma membrane arrangement, extracellular matrix architecture and composition, and cellular structures playing a role in cell adhesion to the surface. It is anticipated that the developed approach will be relevant for the design of efficient cell-instructive platforms in the study of cellular guidance strategies for tissue-engineering applications as well as for in vitro 3D models.
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Affiliation(s)
- Donata Iandolo
- Department of Chemical Engineering and Biotechnology, University of Cambridge, UK
| | - Fabrizio A Pennacchio
- Center for Advanced Biomaterials for Healthcare, Istituto Italiano di Tecnologia, 80125, Italy
| | - Valentina Mollo
- Center for Advanced Biomaterials for Healthcare, Istituto Italiano di Tecnologia, 80125, Italy
| | - Domenico Rossi
- Center for Advanced Biomaterials for Healthcare, Istituto Italiano di Tecnologia, 80125, Italy
| | - David Dannhauser
- Center for Advanced Biomaterials for Healthcare, Istituto Italiano di Tecnologia, 80125, Italy
| | - Bianxiao Cui
- Department of Chemistry, Stanford University, CA, 94305, USA
| | - Roisin M Owens
- Department of Chemical Engineering and Biotechnology, University of Cambridge, UK
| | - Francesca Santoro
- Center for Advanced Biomaterials for Healthcare, Istituto Italiano di Tecnologia, 80125, Italy
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5
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Belu A, Schnitker J, Bertazzo S, Neumann E, Mayer D, Offenhäusser A, Santoro F. Ultra-thin resin embedding method for scanning electron microscopy of individual cells on high and low aspect ratio 3D nanostructures. J Microsc 2016; 263:78-86. [PMID: 26820619 DOI: 10.1111/jmi.12378] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 12/09/2015] [Indexed: 01/18/2023]
Abstract
The preparation of biological cells for either scanning or transmission electron microscopy requires a complex process of fixation, dehydration and drying. Critical point drying is commonly used for samples investigated with a scanning electron beam, whereas resin-infiltration is typically used for transmission electron microscopy. Critical point drying may cause cracks at the cellular surface and a sponge-like morphology of nondistinguishable intracellular compartments. Resin-infiltrated biological samples result in a solid block of resin, which can be further processed by mechanical sectioning, however that does not allow a top view examination of small cell-cell and cell-surface contacts. Here, we propose a method for removing resin excess on biological samples before effective polymerization. In this way the cells result to be embedded in an ultra-thin layer of epoxy resin. This novel method highlights in contrast to standard methods the imaging of individual cells not only on nanostructured planar surfaces but also on topologically challenging substrates with high aspect ratio three-dimensional features by scanning electron microscopy.
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Affiliation(s)
- A Belu
- Institute of Complex Systems and Peter Grünberg Institute (ICS-8/PGI-8) - Bioelectronics, Forschungszentrum Jülich GmbH, Jülich, and JARA-Fundamentals of Future Information Technology, Germany
| | - J Schnitker
- Institute of Complex Systems and Peter Grünberg Institute (ICS-8/PGI-8) - Bioelectronics, Forschungszentrum Jülich GmbH, Jülich, and JARA-Fundamentals of Future Information Technology, Germany
| | - S Bertazzo
- Department of Medical Physics & Biomedical Engineering, University College London, Malet Place Engineering Building, London WC1E 6BT, U.K
| | - E Neumann
- Institute of Complex Systems and Peter Grünberg Institute (ICS-8/PGI-8) - Bioelectronics, Forschungszentrum Jülich GmbH, Jülich, and JARA-Fundamentals of Future Information Technology, Germany
| | - D Mayer
- Institute of Complex Systems and Peter Grünberg Institute (ICS-8/PGI-8) - Bioelectronics, Forschungszentrum Jülich GmbH, Jülich, and JARA-Fundamentals of Future Information Technology, Germany
| | - A Offenhäusser
- Institute of Complex Systems and Peter Grünberg Institute (ICS-8/PGI-8) - Bioelectronics, Forschungszentrum Jülich GmbH, Jülich, and JARA-Fundamentals of Future Information Technology, Germany
| | - F Santoro
- Institute of Complex Systems and Peter Grünberg Institute (ICS-8/PGI-8) - Bioelectronics, Forschungszentrum Jülich GmbH, Jülich, and JARA-Fundamentals of Future Information Technology, Germany
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Bosch C, Martínez A, Masachs N, Teixeira CM, Fernaud I, Ulloa F, Pérez-Martínez E, Lois C, Comella JX, DeFelipe J, Merchán-Pérez A, Soriano E. FIB/SEM technology and high-throughput 3D reconstruction of dendritic spines and synapses in GFP-labeled adult-generated neurons. Front Neuroanat 2015; 9:60. [PMID: 26052271 PMCID: PMC4440362 DOI: 10.3389/fnana.2015.00060] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 04/29/2015] [Indexed: 12/24/2022] Open
Abstract
The fine analysis of synaptic contacts is usually performed using transmission electron microscopy (TEM) and its combination with neuronal labeling techniques. However, the complex 3D architecture of neuronal samples calls for their reconstruction from serial sections. Here we show that focused ion beam/scanning electron microscopy (FIB/SEM) allows efficient, complete, and automatic 3D reconstruction of identified dendrites, including their spines and synapses, from GFP/DAB-labeled neurons, with a resolution comparable to that of TEM. We applied this technology to analyze the synaptogenesis of labeled adult-generated granule cells (GCs) in mice. 3D reconstruction of dendritic spines in GCs aged 3–4 and 8–9 weeks revealed two different stages of dendritic spine development and unexpected features of synapse formation, including vacant and branched dendritic spines and presynaptic terminals establishing synapses with up to 10 dendritic spines. Given the reliability, efficiency, and high resolution of FIB/SEM technology and the wide use of DAB in conventional EM, we consider FIB/SEM fundamental for the detailed characterization of identified synaptic contacts in neurons in a high-throughput manner.
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Affiliation(s)
- Carles Bosch
- Developmental Neurobiology and Regeneration Unit, Department of Cell Biology and Parc Cientific de Barcelona, University of Barcelona Barcelona, Spain ; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Insituto de Salul Carlos III Madrid, Spain ; Institut de Recerca de l'Hospital Universitari de la Vall d'Hebron (VHIR) Barcelona, Spain
| | - Albert Martínez
- Developmental Neurobiology and Regeneration Unit, Department of Cell Biology and Parc Cientific de Barcelona, University of Barcelona Barcelona, Spain
| | - Nuria Masachs
- Developmental Neurobiology and Regeneration Unit, Department of Cell Biology and Parc Cientific de Barcelona, University of Barcelona Barcelona, Spain ; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Insituto de Salul Carlos III Madrid, Spain
| | - Cátia M Teixeira
- Developmental Neurobiology and Regeneration Unit, Department of Cell Biology and Parc Cientific de Barcelona, University of Barcelona Barcelona, Spain ; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Insituto de Salul Carlos III Madrid, Spain
| | - Isabel Fernaud
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Insituto de Salul Carlos III Madrid, Spain ; Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Campus de Montegancedo Madrid, Spain ; Instituto Cajal (Consejo Superior de Investigaciones Científicas) Madrid, Spain
| | - Fausto Ulloa
- Developmental Neurobiology and Regeneration Unit, Department of Cell Biology and Parc Cientific de Barcelona, University of Barcelona Barcelona, Spain ; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Insituto de Salul Carlos III Madrid, Spain
| | - Esther Pérez-Martínez
- Developmental Neurobiology and Regeneration Unit, Department of Cell Biology and Parc Cientific de Barcelona, University of Barcelona Barcelona, Spain ; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Insituto de Salul Carlos III Madrid, Spain
| | - Carlos Lois
- Department of Neurobiology, University of Massachusetts Medical School Worcester, MA, USA
| | - Joan X Comella
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Insituto de Salul Carlos III Madrid, Spain ; Institut de Recerca de l'Hospital Universitari de la Vall d'Hebron (VHIR) Barcelona, Spain ; Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona Bellaterra, Spain
| | - Javier DeFelipe
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Insituto de Salul Carlos III Madrid, Spain ; Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Campus de Montegancedo Madrid, Spain ; Instituto Cajal (Consejo Superior de Investigaciones Científicas) Madrid, Spain
| | - Angel Merchán-Pérez
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Insituto de Salul Carlos III Madrid, Spain ; Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Campus de Montegancedo Madrid, Spain ; Departamento de Arquitectura y Tecnología de Sistemas Informáticos, Escuela Técnica Superior de Ingenieros Informáticos, Universidad Politécnica de Madrid Madrid, Spain
| | - Eduardo Soriano
- Developmental Neurobiology and Regeneration Unit, Department of Cell Biology and Parc Cientific de Barcelona, University of Barcelona Barcelona, Spain ; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Insituto de Salul Carlos III Madrid, Spain ; Institut de Recerca de l'Hospital Universitari de la Vall d'Hebron (VHIR) Barcelona, Spain ; Institució Catalana de Recerca i Estudis Avançats Academia Barcelona, Spain
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7
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Three-dimensional architecture of podocytes revealed by block-face scanning electron microscopy. Sci Rep 2015; 5:8993. [PMID: 25759085 PMCID: PMC4355681 DOI: 10.1038/srep08993] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 02/12/2015] [Indexed: 12/31/2022] Open
Abstract
Block-face imaging is a scanning electron microscopic technique which enables easier acquisition of serial ultrastructural images directly from the surface of resin-embedded biological samples with a similar quality to transmission electron micrographs. In the present study, we analyzed the three-dimensional architecture of podocytes using serial block-face imaging. It was previously believed that podocytes are divided into three kinds of subcellular compartment: cell body, primary process, and foot process, which are simply aligned in this order. When the reconstructed podocytes were viewed from their basal side, the foot processes were branched from a ridge-like prominence, which was formed on the basal surface of the primary process and was similar to the usual foot processes in structure. Moreover, from the cell body, the foot processes were also emerged via the ridge-like prominence, as found in the primary process. The ridge-like prominence anchored the cell body and primary process to the glomerular basement membrane, and connected the foot processes to the cell body and primary process. In conclusion, serial block-face imaging is a powerful tool for clear understanding the three-dimensional architecture of podocytes through its ability to reveal novel structures which were difficult to determine by conventional transmission and scanning electron microscopes alone.
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Mourik MJ, Faas FGA, Zimmermann H, Eikenboom J, Koster AJ. Towards the imaging of Weibel-Palade body biogenesis by serial block face-scanning electron microscopy. J Microsc 2015; 259:97-104. [PMID: 25644989 PMCID: PMC4670698 DOI: 10.1111/jmi.12222] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 12/23/2014] [Indexed: 12/25/2022]
Abstract
Electron microscopy is used in biological research to study the ultrastructure at high resolution to obtain information on specific cellular processes. Serial block face-scanning electron microscopy is a relatively novel electron microscopy imaging technique that allows three-dimensional characterization of the ultrastructure in both tissues and cells by measuring volumes of thousands of cubic micrometres yet at nanometre-scale resolution. In the scanning electron microscope, repeatedly an image is acquired followed by the removal of a thin layer resin embedded biological material by either a microtome or a focused ion beam. In this way, each recorded image contains novel structural information which can be used for three-dimensional analysis. Here, we explore focused ion beam facilitated serial block face-scanning electron microscopy to study the endothelial cell–specific storage organelles, the Weibel–Palade bodies, during their biogenesis at the Golgi apparatus. Weibel–Palade bodies predominantly contain the coagulation protein Von Willebrand factor which is secreted by the cell upon vascular damage. Using focused ion beam facilitated serial block face-scanning electron microscopy we show that the technique has the sensitivity to clearly reveal subcellular details like mitochondrial cristae and small vesicles with a diameter of about 50 nm. Also, we reveal numerous associations between Weibel–Palade bodies and Golgi stacks which became conceivable in large-scale three-dimensional data. We demonstrate that serial block face-scanning electron microscopy is a promising tool that offers an alternative for electron tomography to study subcellular organelle interactions in the context of a complete cell.
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Affiliation(s)
- M J Mourik
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - F G A Faas
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
| | | | - J Eikenboom
- Department of Thrombosis and Hemostasis, Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - A J Koster
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
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Anton-Sanchez L, Bielza C, Merchán-Pérez A, Rodríguez JR, DeFelipe J, Larrañaga P. Three-dimensional distribution of cortical synapses: a replicated point pattern-based analysis. Front Neuroanat 2014; 8:85. [PMID: 25206325 PMCID: PMC4143965 DOI: 10.3389/fnana.2014.00085] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 08/02/2014] [Indexed: 11/13/2022] Open
Abstract
The biggest problem when analyzing the brain is that its synaptic connections are extremely complex. Generally, the billions of neurons making up the brain exchange information through two types of highly specialized structures: chemical synapses (the vast majority) and so-called gap junctions (a substrate of one class of electrical synapse). Here we are interested in exploring the three-dimensional spatial distribution of chemical synapses in the cerebral cortex. Recent research has showed that the three-dimensional spatial distribution of synapses in layer III of the neocortex can be modeled by a random sequential adsorption (RSA) point process, i.e., synapses are distributed in space almost randomly, with the only constraint that they cannot overlap. In this study we hypothesize that RSA processes can also explain the distribution of synapses in all cortical layers. We also investigate whether there are differences in both the synaptic density and spatial distribution of synapses between layers. Using combined focused ion beam milling and scanning electron microscopy (FIB/SEM), we obtained three-dimensional samples from the six layers of the rat somatosensory cortex and identified and reconstructed the synaptic junctions. A total volume of tissue of approximately 4500μm(3) and around 4000 synapses from three different animals were analyzed. Different samples, layers and/or animals were aggregated and compared using RSA replicated spatial point processes. The results showed no significant differences in the synaptic distribution across the different rats used in the study. We found that RSA processes described the spatial distribution of synapses in all samples of each layer. We also found that the synaptic distribution in layers II to VI conforms to a common underlying RSA process with different densities per layer. Interestingly, the results showed that synapses in layer I had a slightly different spatial distribution from the other layers.
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Affiliation(s)
- Laura Anton-Sanchez
- Departamento de Inteligencia Artificial, Escuela Técnica Superior de Ingenieros Informáticos, Universidad Politécnica de Madrid Madrid, Spain
| | - Concha Bielza
- Departamento de Inteligencia Artificial, Escuela Técnica Superior de Ingenieros Informáticos, Universidad Politécnica de Madrid Madrid, Spain
| | - Angel Merchán-Pérez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid Madrid, Spain ; Departamento de Arquitectura y Tecnología de Sistemas Informáticos, Escuela Técnica Superior de Ingenieros Informáticos, Universidad Politécnica de Madrid Madrid, Spain
| | - José-Rodrigo Rodríguez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid Madrid, Spain ; Instituto Cajal, Consejo Superior de Investigaciones Científicas Madrid, Spain
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid Madrid, Spain ; Instituto Cajal, Consejo Superior de Investigaciones Científicas Madrid, Spain
| | - Pedro Larrañaga
- Departamento de Inteligencia Artificial, Escuela Técnica Superior de Ingenieros Informáticos, Universidad Politécnica de Madrid Madrid, Spain
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Lehmann T, Heß M, Wanner G, Melzer RR. Dissecting a neuron network: FIB-SEM-based 3D-reconstruction of the visual neuropils in the sea spider Achelia langi (Dohrn, 1881) (Pycnogonida). BMC Biol 2014; 12:59. [PMID: 25285383 PMCID: PMC4159573 DOI: 10.1186/s12915-014-0059-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/21/2014] [Indexed: 03/22/2024] Open
Abstract
BACKGROUND The research field of connectomics arose just recently with the development of new three-dimensional-electron microscopy (EM) techniques and increasing computing power. So far, only a few model species (for example, mouse, the nematode Caenorhabditis elegans, and the fruit fly Drosophila melanogaster) have been studied using this approach. Here, we present a first attempt to expand this circle to include pycnogonids, which hold a key position for the understanding of arthropod evolution. The visual neuropils in Achelia langi are studied using a focused ion beam-scanning electron microscope (FIB-SEM) crossbeam-workstation, and a three-dimensional serial reconstruction of the connectome is presented. RESULTS The two eyes of each hemisphere of the sea spider's eye tubercle are connected to a first and a second visual neuropil. The first visual neuropil is subdivided in two hemineuropils, each responsible for one eye and stratified into three layers. Six different neuron types postsynaptic to the retinula (R-cells) axons are characterized by their morphology: five types of descending unipolar neurons and one type of ascending neurons. These cell types are also identified by Golgi impregnations. Mapping of all identifiable chemical synapses indicates that the descending unipolar neurons are postsynaptic to the R-cells and, hence, are second-order neurons. The ascending neurons are predominantly presynaptic and sometimes postsynaptic to the R-cells and may play a feedback role. CONCLUSIONS Comparing these results with the compound eye visual system of crustaceans and insects - the only arthropod visual system studied so far in such detail - we found striking similarities in the morphology and synaptic organization of the different neuron types. Hence, the visual system of pycnogonids shows features of both chelicerate median and mandibulate lateral eyes.
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Affiliation(s)
- Tobias Lehmann
- />Bavarian State Collection of Zoology – SNSB, Münchhausenstraße 21, 81247 Munich, Germany
- />Department Biology II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany
| | - Martin Heß
- />Department Biology II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany
- />GeoBio-Center LMU, Richard-Wagner-Straße 10, 80333 Munich, Germany
| | - Gerhard Wanner
- />Department Biology I, Ludwig-Maximilians-Universität München, Großhaderner Straße 2-4, 82152 Planegg-Martinsried, Germany
| | - Roland R Melzer
- />Bavarian State Collection of Zoology – SNSB, Münchhausenstraße 21, 81247 Munich, Germany
- />Department Biology II, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany
- />GeoBio-Center LMU, Richard-Wagner-Straße 10, 80333 Munich, Germany
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Lipke E, Hörnschemeyer T, Pakzad A, Booth CR, Michalik P. Serial block-face imaging and its potential for reconstructing diminutive cell systems: a case study from arthropods. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:946-955. [PMID: 24555994 DOI: 10.1017/s1431927614000087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Until recently, three-dimensional reconstruction on an ultrastructural level was only possible using serial section transmission electron microscopy (ssTEM). However, ssTEM is highly challenging and prone to artifacts as, e.g., section loss and image distortions. New methods, such as serial block-face scanning electron microscopy (SBFSEM) overcome these limitations and promise a high lateral resolution. However, little is known about the usability of SBFSEM in diminutive, but highly complex cellular systems. We used spider sperm (~3 µm in diameter), which fulfills these conditions, to analyze the potential of SBFSEM compared with ssTEM. Our data suggest that the resolution obtained by SBFSEM allows depicting structures on a cellular level and is sufficient to discriminate subcellular components, but is highly dependent on previous staining procedures and electron density of the target structures.
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Affiliation(s)
- Elisabeth Lipke
- 1Allgemeine und Systematische Zoologie,Zoologisches Institut und Museum,Ernst-Moritz-Arndt-Universität,J.-S.-Bach-Str. 11/12,D-17487 Greifswald,Germany
| | - Thomas Hörnschemeyer
- 2Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology,Department of Morphology,Systematics and Evolutionary Biology,Georg-August-University,Göttingen,Germany
| | | | | | - Peter Michalik
- 1Allgemeine und Systematische Zoologie,Zoologisches Institut und Museum,Ernst-Moritz-Arndt-Universität,J.-S.-Bach-Str. 11/12,D-17487 Greifswald,Germany
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12
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Sonomura T, Furuta T, Nakatani I, Yamamoto Y, Unzai T, Matsuda W, Iwai H, Yamanaka A, Uemura M, Kaneko T. Correlative analysis of immunoreactivity in confocal laser-scanning microscopy and scanning electron microscopy with focused ion beam milling. Front Neural Circuits 2013; 7:26. [PMID: 23443927 PMCID: PMC3581071 DOI: 10.3389/fncir.2013.00026] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 02/05/2013] [Indexed: 01/28/2023] Open
Abstract
Recently, three-dimensional reconstruction of ultrastructure of the brain has been realized with minimal effort by using scanning electron microscopy (SEM) combined with focused ion beam (FIB) milling (FIB-SEM). Application of immunohistochemical staining in electron microscopy (EM) provides a great advantage in that molecules of interest are specifically localized in ultrastructures. Thus, we applied immunocytochemistry for FIB-SEM and correlated this immunoreactivity with that in confocal laser-scanning microcopy (CF-LSM). Dendrites of medium-sized spiny neurons in the rat neostriatum were visualized using a recombinant viral vector, which labeled the infected neurons with membrane-targeted GFP in a Golgi stain-like fashion. Moreover, the thalamostriatal afferent terminals were immunolabeled with Cy5 fluorescence for vesicular glutamate transporter 2 (VGluT2). After detection of the sites of terminals apposed to the dendrites by using CF-LSM, GFP and VGluT2 immunoreactivities were further developed for EM by using immunogold/silver enhancement and immunoperoxidase/diaminobenzidine (DAB) methods, respectively. In contrast-inverted FIB-SEM images, silver precipitations and DAB deposits were observed as fine dark grains and diffuse dense profiles, respectively, indicating that these immunoreactivities were as easily recognizable as those in the transmission electron microscopy (TEM) images. Furthermore, in the sites of interest, some appositions displayed synaptic specializations of an asymmetric type. Thus, the present method was useful in the three-dimensional analysis of immunocytochemically differentiated synaptic connections in the central neural circuit.
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Affiliation(s)
- Takahiro Sonomura
- Department of Anatomy for Oral Sciences, Graduate School of Medical and Dental Sciences, Kagoshima University Kagoshima, Japan
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13
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Merchán-Pérez A, Rodríguez JR, González S, Robles V, DeFelipe J, Larrañaga P, Bielza C. Three-dimensional spatial distribution of synapses in the neocortex: a dual-beam electron microscopy study. ACTA ACUST UNITED AC 2013; 24:1579-88. [PMID: 23365213 PMCID: PMC4014183 DOI: 10.1093/cercor/bht018] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
In the cerebral cortex, most synapses are found in the neuropil, but relatively little is known about their 3-dimensional organization. Using an automated dual-beam electron microscope that combines focused ion beam milling and scanning electron microscopy, we have been able to obtain 10 three-dimensional samples with an average volume of 180 µm3 from the neuropil of layer III of the young rat somatosensory cortex (hindlimb representation). We have used specific software tools to fully reconstruct 1695 synaptic junctions present in these samples and to accurately quantify the number of synapses per unit volume. These tools also allowed us to determine synapse position and to analyze their spatial distribution using spatial statistical methods. Our results indicate that the distribution of synaptic junctions in the neuropil is nearly random, only constrained by the fact that synapses cannot overlap in space. A theoretical model based on random sequential absorption, which closely reproduces the actual distribution of synapses, is also presented.
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Affiliation(s)
- Angel Merchán-Pérez
- Laboratorio Cajal de Circuitos Corticales
- Departamento de Arquitectura y Tecnología de Sistemas Informáticos, Universidad Politécnica de Madrid, Pozuelo de Alarcón,Madrid 28223, Spain
| | - José-Rodrigo Rodríguez
- Laboratorio Cajal de Circuitos Corticales
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid 28002, Spain and
| | - Santiago González
- Laboratorio de Minería de Datos y Simulación, Centro de Tecnología Biomédica
| | - Víctor Robles
- Laboratorio de Minería de Datos y Simulación, Centro de Tecnología Biomédica
- Departamento de Arquitectura y Tecnología de Sistemas Informáticos, Universidad Politécnica de Madrid, Pozuelo de Alarcón,Madrid 28223, Spain
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid 28002, Spain and
| | - Pedro Larrañaga
- Departamento de Inteligencia Artificial, Universidad Politécnica de Madrid, Boadilla del Monte, Madrid 28660, Spain
| | - Concha Bielza
- Departamento de Inteligencia Artificial, Universidad Politécnica de Madrid, Boadilla del Monte, Madrid 28660, Spain
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14
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Subcellular Microanatomy by 3D Deconvolution Brightfield Microscopy: Method and Analysis Using Human Chromatin in the Interphase Nucleus. ANATOMY RESEARCH INTERNATIONAL 2012; 2012:848707. [PMID: 22567315 PMCID: PMC3342522 DOI: 10.1155/2012/848707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Accepted: 10/19/2011] [Indexed: 11/23/2022]
Abstract
Anatomy has advanced using 3-dimensional (3D) studies at macroscopic (e.g., dissection, injection moulding of vessels, radiology) and microscopic (e.g., serial section reconstruction with light and electron microscopy) levels. This paper presents the first results in human cells of a new method of subcellular 3D brightfield microscopy. Unlike traditional 3D deconvolution and confocal techniques, this method is suitable for general application to brightfield microscopy. Unlike brightfield serial sectioning it has subcellular resolution. Results are presented of the 3D structure of chromatin in the interphase nucleus of two human cell types, hepatocyte and plasma cell. I show how the freedom to examine these structures in 3D allows greater morphological discrimination between and within cell types and the 3D structural basis for the classical “clock-face” motif of the plasma cell nucleus is revealed. Potential for further applications discussed.
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15
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Horstmann H, Körber C, Sätzler K, Aydin D, Kuner T. Serial section scanning electron microscopy (S3EM) on silicon wafers for ultra-structural volume imaging of cells and tissues. PLoS One 2012; 7:e35172. [PMID: 22523574 PMCID: PMC3327660 DOI: 10.1371/journal.pone.0035172] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 03/09/2012] [Indexed: 11/19/2022] Open
Abstract
High resolution, three-dimensional (3D) representations of cellular ultrastructure are essential for structure function studies in all areas of cell biology. While limited subcellular volumes have been routinely examined using serial section transmission electron microscopy (ssTEM), complete ultrastructural reconstructions of large volumes, entire cells or even tissue are difficult to achieve using ssTEM. Here, we introduce a novel approach combining serial sectioning of tissue with scanning electron microscopy (SEM) using a conductive silicon wafer as a support. Ribbons containing hundreds of 35 nm thick sections can be generated and imaged on the wafer at a lateral pixel resolution of 3.7 nm by recording the backscattered electrons with the in-lens detector of the SEM. The resulting electron micrographs are qualitatively comparable to those obtained by conventional TEM. S3EM images of the same region of interest in consecutive sections can be used for 3D reconstructions of large structures. We demonstrate the potential of this approach by reconstructing a 31.7 µm3 volume of a calyx of Held presynaptic terminal. The approach introduced here, Serial Section SEM (S3EM), for the first time provides the possibility to obtain 3D ultrastructure of large volumes with high resolution and to selectively and repetitively home in on structures of interest. S3EM accelerates process duration, is amenable to full automation and can be implemented with standard instrumentation.
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Affiliation(s)
- Heinz Horstmann
- Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Christoph Körber
- Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Kurt Sätzler
- Biomedical Sciences Research Institute, University of Ulster, Coleraine, Northern Ireland
| | - Daniel Aydin
- Department of Biophysical Chemistry, Heidelberg University, Heidelberg, Germany
| | - Thomas Kuner
- Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
- * E-mail:
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16
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17
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Tapia JC, Kasthuri N, Hayworth KJ, Schalek R, Lichtman JW, Smith SJ, Buchanan J. High-contrast en bloc staining of neuronal tissue for field emission scanning electron microscopy. Nat Protoc 2012; 7:193-206. [PMID: 22240582 DOI: 10.1038/nprot.2011.439] [Citation(s) in RCA: 178] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Conventional heavy metal poststaining methods on thin sections lend contrast but often cause contamination. To avoid this problem, we tested several en bloc staining techniques to contrast tissue in serial sections mounted on solid substrates for examination by field emission scanning electron microscopy (FESEM). Because FESEM section imaging requires that specimens have higher contrast and greater electrical conductivity than transmission electron microscopy (TEM) samples, our technique uses osmium impregnation (OTO) to make the samples conductive while heavily staining membranes for segmentation studies. Combining this step with other classic heavy metal en bloc stains, including uranyl acetate (UA), lead aspartate, copper sulfate and lead citrate, produced clean, highly contrasted TEM and scanning electron microscopy (SEM) samples of insect, fish and mammalian nervous systems. This protocol takes 7-15 d to prepare resin-embedded tissue, cut sections and produce serial section images.
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Affiliation(s)
- Juan Carlos Tapia
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
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18
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Morales J, Alonso-Nanclares L, Rodríguez JR, Defelipe J, Rodríguez A, Merchán-Pérez A. Espina: a tool for the automated segmentation and counting of synapses in large stacks of electron microscopy images. Front Neuroanat 2011; 5:18. [PMID: 21633491 PMCID: PMC3099746 DOI: 10.3389/fnana.2011.00018] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 03/01/2011] [Indexed: 11/13/2022] Open
Abstract
The synapses in the cerebral cortex can be classified into two main types, Gray's type I and type II, which correspond to asymmetric (mostly glutamatergic excitatory) and symmetric (inhibitory GABAergic) synapses, respectively. Hence, the quantification and identification of their different types and the proportions in which they are found, is extraordinarily important in terms of brain function. The ideal approach to calculate the number of synapses per unit volume is to analyze 3D samples reconstructed from serial sections. However, obtaining serial sections by transmission electron microscopy is an extremely time consuming and technically demanding task. Using focused ion beam/scanning electron microscope microscopy, we recently showed that virtually all synapses can be accurately identified as asymmetric or symmetric synapses when they are visualized, reconstructed, and quantified from large 3D tissue samples obtained in an automated manner. Nevertheless, the analysis, segmentation, and quantification of synapses is still a labor intensive procedure. Thus, novel solutions are currently necessary to deal with the large volume of data that is being generated by automated 3D electron microscopy. Accordingly, we have developed ESPINA, a software tool that performs the automated segmentation and counting of synapses in a reconstructed 3D volume of the cerebral cortex, and that greatly facilitates and accelerates these processes.
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Affiliation(s)
- Juan Morales
- Departamento de Tecnología Fotónica, Universidad Politécnica de Madrid Madrid, Spain
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19
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Kaynig V, Fuchs TJ, Buhmann JM. Geometrical consistent 3D tracing of neuronal processes in ssTEM data. ACTA ACUST UNITED AC 2010; 13:209-16. [PMID: 20879317 DOI: 10.1007/978-3-642-15745-5_26] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
In neuroanatomy, automatic geometry extraction of neurons from electron microscopy images is becoming one of the main limiting factors in getting new insights into the functional structure of the brain. We propose a novel framework for tracing neuronal processes over serial sections for 3d reconstructions. The automatic processing pipeline combines the probabilistic output of a random forest classifier with geometrical consistency constraints which take the geometry of whole sections into account. Our experiments demonstrate significant improvement over grouping by Euclidean distance, reducing the split and merge error per object by a factor of two.
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Affiliation(s)
- Verena Kaynig
- Department of Computer Science, ETH Zurich, Switzerland.
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20
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The micro-architecture of mitochondria at active zones: electron tomography reveals novel anchoring scaffolds and cristae structured for high-rate metabolism. J Neurosci 2010; 30:1015-26. [PMID: 20089910 DOI: 10.1523/jneurosci.1517-09.2010] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Mitochondria are integral elements of many nerve terminals. They must be appropriately positioned to regulate microdomains of Ca(2+) concentration and metabolic demand, but structures that anchor them in place have not been described. By applying the high resolution of electron tomography (ET) to the study of a central terminal, the calyx of Held, we revealed an elaborate cytoskeletal superstructure that connected a subset of mitochondria to the presynaptic membrane near active zones. This cytoskeletal network extended laterally and was well integrated into the nerve terminal cytoskeleton, which included filamentous linkages among synaptic vesicles. ET revealed novel features of inner membrane for these mitochondria. Crista structure was polarized in that crista junctions, circular openings of the inner membrane under the outer membrane, were aligned with the cytoskeletal superstructure and occurred at higher density in mitochondrial membrane facing the presynaptic membrane. These characteristics represent the first instance where a subcomponent of an organelle is shown to have a specific orientation relative to the polarized structure of a cell. The ratio of cristae to outer membrane surface area is large in these mitochondria relative to other tissues, indicating a high metabolic capacity. These observations suggest general principles for cytoskeletal anchoring of mitochondria in all tissues, reveal potential routes for nonsynaptic communication between presynaptic and postsynaptic partners using this novel cytoskeletal framework, and indicate that crista structure can be specialized for particular functions within cellular microdomains.
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21
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Merchán-Pérez A, Rodriguez JR, Alonso-Nanclares L, Schertel A, Defelipe J. Counting Synapses Using FIB/SEM Microscopy: A True Revolution for Ultrastructural Volume Reconstruction. Front Neuroanat 2009; 3:18. [PMID: 19949485 PMCID: PMC2784681 DOI: 10.3389/neuro.05.018.2009] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Accepted: 09/02/2009] [Indexed: 11/13/2022] Open
Abstract
The advent of transmission electron microscopy (TEM) in the 1950s represented a fundamental step in the study of neuronal circuits. The application of this technique soon led to the realization that the number of synapses changes during the course of normal life, as well as under certain pathological or experimental circumstances. Since then, one of the main goals in neurosciences has been to define simple and accurate methods to estimate the magnitude of these changes. Contrary to analysing single sections, TEM reconstructions are extremely time-consuming and difficult. Therefore, most quantitative studies use stereological methods to define the three-dimensional characteristics of synaptic junctions that are studied in two dimensions. Here, to count the exact number of synapses per unit of volume we have applied a new three-dimensional reconstruction method that involves the combination of focused ion beam milling and scanning electron microscopy (FIB/SEM). We show that the images obtained with FIB/SEM are similar to those obtained with TEM, but with the advantage that FIB/SEM permits serial reconstructions of large volumes of tissue to be generated rapidly and automatically. Furthermore, we compared the estimates of the number of synapses obtained with stereological methods with the values obtained by FIB/SEM reconstructions. We concluded that FIB/SEM not only provides the actual number of synapses per volume but it is also much easier and faster to use than other currently available TEM methods. More importantly, it also avoids most of the errors introduced by stereological methods and overcomes the difficulties associated with these techniques.
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Affiliation(s)
- Angel Merchán-Pérez
- Laboratorio de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid Madrid, Spain
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22
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A protocol for preparing GFP-labeled neurons previously imaged in vivo and in slice preparations for light and electron microscopic analysis. Nat Protoc 2009; 4:1145-56. [PMID: 19617886 DOI: 10.1038/nprot.2009.114] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In vivo imaging of green fluorescent protein (GFP)-labeled neurons in the intact brain is being used increasingly to study neuronal plasticity. However, interpreting the observed changes as modifications in neuronal connectivity needs information about synapses. We show here that axons and dendrites of GFP-labeled neurons imaged previously in the live mouse or in slice preparations using 2-photon laser microscopy can be analyzed using light and electron microscopy, allowing morphological reconstruction of the synapses both on the imaged neurons, as well as those in the surrounding neuropil. We describe how, over a 2-day period, the imaged tissue is fixed, sliced and immuno-labeled to localize the neurons of interest. Once embedded in epoxy resin, the entire neuron can then be drawn in three dimensions (3D) for detailed morphological analysis using light microscopy. Specific dendrites and axons can be further serially thin sectioned, imaged in the electron microscope (EM) and then the ultrastructure analyzed on the serial images.
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23
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Joris PX, Smith PH. The volley theory and the spherical cell puzzle. Neuroscience 2008; 154:65-76. [PMID: 18424004 DOI: 10.1016/j.neuroscience.2008.03.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 03/05/2008] [Accepted: 03/05/2008] [Indexed: 11/26/2022]
Abstract
Temporal coding in the auditory nerve is strikingly transformed in the cochlear nucleus. In contrast to fibers in the auditory nerve, some neurons in the cochlear nucleus can show "picket fence" phase-locking to low-frequency pure tones: they fire a precisely timed action potential at every cycle of the stimulus. Such synchronization enhancement and entrainment is particularly prominent in neurons with the spherical and globular morphology, described by Osen [Osen KK (1969) Cytoarchitecture of the cochlear nuclei in the cat. J Comp Neurol 136:453-483]. These neurons receive large axosomatic terminals from the auditory nerve--the end bulbs and modified end bulbs of Held--and project to binaural comparator nuclei in the superior olivary complex. The most popular model to account for picket fence phase-locking is monaural coincidence detection. This mechanism is plausible for globular neurons, which receive a large number of inputs. We draw attention to the existence of enhanced phase-locking and entrainment in spherical neurons, which receive too few end-bulb inputs from the auditory nerve to make a coincidence detection of end-bulb firings a plausible mechanism of synchronization enhancement.
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Affiliation(s)
- P X Joris
- Laboratory of Auditory Neurophysiology, K.U.Leuven, Campus GHB O&N2, Herestraat 49 bus 1021, B-3000 Leuven, Belgium.
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24
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Kopp-Scheinpflug C, Tolnai S, Malmierca MS, Rübsamen R. The medial nucleus of the trapezoid body: comparative physiology. Neuroscience 2008; 154:160-70. [PMID: 18436383 DOI: 10.1016/j.neuroscience.2008.01.088] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 01/31/2008] [Accepted: 01/31/2008] [Indexed: 11/26/2022]
Abstract
Principal cells of the medial nucleus of the trapezoid body (MNTB) receive their excitatory input through large somatic terminals, the calyces of Held, which arise from axons of globular bushy cells located in the contralateral ventral cochlear nucleus. Discharges of MNTB neurons are characterized by high stimulus evoked firing rates, temporally precise onset responses, and a high degree of phase-locking to either pure tones or stimulus envelopes. Since the calyx of Held synapse is accessible to in vitro and to in vivo recordings, it serves as one of the most elaborate models for studying synaptic transmission in the mammalian brain. Although in such studies, the major emphasis is on synaptic physiology, the interpretation of the data will benefit from an understanding of the MNTB's contribution to auditory signal processing, including possible functional differences in different species. This implies the consideration of possible functional differences in different species. Here, we compare single unit recordings from MNTB principal cells in vivo in three different rodent species: gerbil, mouse and rat. Because of their good low-frequency hearing gerbils are often used in in vivo preparations, while mice and rats are predominantly used in slice preparations. We show that MNTB units in all three species exhibit high firing rates and precise onset-timing. Still there are species-specific specializations that might suggest the preferential use of one species over the others, depending on the scope of the respective investigation.
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Affiliation(s)
- C Kopp-Scheinpflug
- Faculty of Bioscience, Pharmacy and Psychology, University of Leipzig, Talstrasse 33, 04103 Leipzig, Germany
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25
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Starborg T, Lu Y, Kadler KE, Holmes DF. Electron microscopy of collagen fibril structure in vitro and in vivo including three-dimensional reconstruction. Methods Cell Biol 2008; 88:319-45. [PMID: 18617041 DOI: 10.1016/s0091-679x(08)00417-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Tissue development in multicellular animals relies on the ability of cells to synthesize an extracellular matrix (ECM) containing spatially organized collagen fibrils, whose length greatly exceeds that of individual cells. The importance of the correct regulation of fibril deposition is exemplified in diseases such as osteogenesis imperfecta (caused by mutations in collagen genes), fibrosis (caused by ectopic accumulation of collagen), and cardiovascular disease (which involves cells and macromolecules binding to collagen in the vessel wall). Much is known about the molecular biology of collagens but less is known about collagen fibril structure and how the fibrils are formed (fibrillogenesis). This is explained in part by the fact that the fibrils are noncrystalline, extensively cross-linked, and very large, which makes them refractory to study by conventional biochemical and high-resolution structure-determination techniques. Electron microscopy has become established as the method of choice for studying collagen fibril structure and assembly. This article describes the electron microscopic methods most often used in studying collagen fibril assembly and structure.
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Affiliation(s)
- Tobias Starborg
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
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