1
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Regmi KC, Ghosh S, Koch B, Neumann U, Stein B, O'Connell RJ, Innes RW. Three-Dimensional Ultrastructure of Arabidopsis Cotyledons Infected with Colletotrichum higginsianum. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:396-406. [PMID: 38148303 DOI: 10.1094/mpmi-05-23-0068-r] [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: 12/28/2023]
Abstract
We used serial block-face scanning electron microscopy (SBF-SEM) to study the host-pathogen interface between Arabidopsis cotyledons and the hemibiotrophic fungus Colletotrichum higginsianum. By combining high-pressure freezing and freeze-substitution with SBF-SEM, followed by segmentation and reconstruction of the imaging volume using the freely accessible software IMOD, we created 3D models of the series of cytological events that occur during the Colletotrichum-Arabidopsis susceptible interaction. We found that the host cell membranes underwent massive expansion to accommodate the rapidly growing intracellular hypha. As the fungal infection proceeded from the biotrophic to the necrotrophic stage, the host cell membranes went through increasing levels of disintegration culminating in host cell death. Intriguingly, we documented autophagosomes in proximity to biotrophic hyphae using transmission electron microscopy (TEM) and a concurrent increase in autophagic flux between early to mid/late biotrophic phase of the infection process. Occasionally, we observed osmiophilic bodies in the vicinity of biotrophic hyphae using TEM only and near necrotrophic hyphae under both TEM and SBF-SEM. Overall, we established a method for obtaining serial SBF-SEM images, each with a lateral (x-y) pixel resolution of 10 nm and an axial (z) resolution of 40 nm, that can be reconstructed into interactive 3D models using the IMOD. Application of this method to the Colletotrichum-Arabidopsis pathosystem allowed us to more fully understand the spatial arrangement and morphological architecture of the fungal hyphae after they penetrate epidermal cells of Arabidopsis cotyledons and the cytological changes the host cell undergoes as the infection progresses toward necrotrophy. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Kamesh C Regmi
- Indiana University, Department of Biology, Bloomington, IN 47405, U.S.A
| | - Suchismita Ghosh
- Indiana University, Department of Biology, Bloomington, IN 47405, U.S.A
| | - Benjamin Koch
- Indiana University, Department of Biology, Bloomington, IN 47405, U.S.A
| | - Ulla Neumann
- Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Barry Stein
- Indiana University, Department of Biology, Bloomington, IN 47405, U.S.A
| | | | - Roger W Innes
- Indiana University, Department of Biology, Bloomington, IN 47405, U.S.A
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2
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Imaging the Plant Cytoskeleton by High-Pressure Freezing and Electron Tomography. Methods Mol Biol 2023; 2604:89-102. [PMID: 36773227 DOI: 10.1007/978-1-0716-2867-6_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Electron tomography (ET) imaging of high-pressure frozen/freeze-substituted samples provides a unique opportunity to study structural details of organelles and cytoskeletal arrays in plant cells. In this chapter, we discuss approaches for sample preparation by cryofixation at high pressure, freeze substitution, and resin embedding. We also include pipelines for data collection for electron tomography at ambient temperature, tomogram calculation, and segmentation.
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3
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Volland JM, Gonzalez-Rizzo S, Gros O, Tyml T, Ivanova N, Schulz F, Goudeau D, Elisabeth NH, Nath N, Udwary D, Malmstrom RR, Guidi-Rontani C, Bolte-Kluge S, Davies KM, Jean MR, Mansot JL, Mouncey NJ, Angert ER, Woyke T, Date SV. A centimeter-long bacterium with DNA contained in metabolically active, membrane-bound organelles. Science 2022; 376:1453-1458. [PMID: 35737788 DOI: 10.1126/science.abb3634] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cells of most bacterial species are around 2 micrometers in length, with some of the largest specimens reaching 750 micrometers. Using fluorescence, x-ray, and electron microscopy in conjunction with genome sequencing, we characterized Candidatus (Ca.) Thiomargarita magnifica, a bacterium that has an average cell length greater than 9000 micrometers and is visible to the naked eye. These cells grow orders of magnitude over theoretical limits for bacterial cell size, display unprecedented polyploidy of more than half a million copies of a very large genome, and undergo a dimorphic life cycle with asymmetric segregation of chromosomes into daughter cells. These features, along with compartmentalization of genomic material and ribosomes in translationally active organelles bound by bioenergetic membranes, indicate gain of complexity in the Thiomargarita lineage and challenge traditional concepts of bacterial cells.
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Affiliation(s)
- Jean-Marie Volland
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Laboratory for Research in Complex Systems, Menlo Park, CA, USA
| | - Silvina Gonzalez-Rizzo
- Institut de Systématique, Evolution, Biodiversité, Université des Antilles, Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Campus de Fouillole, Pointe-à-Pitre, France
| | - Olivier Gros
- Institut de Systématique, Evolution, Biodiversité, Université des Antilles, Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Campus de Fouillole, Pointe-à-Pitre, France.,Centre Commun de Caractérisation des Matériaux des Antilles et de la Guyane, Université des Antilles, UFR des Sciences Exactes et Naturelles, Pointe-à-Pitre, Guadeloupe, France
| | - Tomáš Tyml
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Laboratory for Research in Complex Systems, Menlo Park, CA, USA
| | - Natalia Ivanova
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Frederik Schulz
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Danielle Goudeau
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Nathalie H Elisabeth
- Department of Energy Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Nandita Nath
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Daniel Udwary
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Rex R Malmstrom
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Chantal Guidi-Rontani
- Institut de Systématique, Evolution, Biodiversité CNRS UMR 7205, Museum National d'Histoire Naturelle, Paris, France
| | - Susanne Bolte-Kluge
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS FRE3631, Institut de Biologie Paris Seine, Paris, France
| | - Karen M Davies
- Department of Energy Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Department of Molecular and Cell Biology, University of California, Berkeley, USA
| | - Maïtena R Jean
- Institut de Systématique, Evolution, Biodiversité, Université des Antilles, Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Campus de Fouillole, Pointe-à-Pitre, France
| | - Jean-Louis Mansot
- Centre Commun de Caractérisation des Matériaux des Antilles et de la Guyane, Université des Antilles, UFR des Sciences Exactes et Naturelles, Pointe-à-Pitre, Guadeloupe, France
| | - Nigel J Mouncey
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Esther R Angert
- Cornell University, College of Agriculture and Life Sciences, Department of Microbiology, Ithaca, NY, USA
| | - Tanja Woyke
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Laboratory for Research in Complex Systems, Menlo Park, CA, USA.,University of California Merced, School of Natural Sciences, Merced, CA, USA
| | - Shailesh V Date
- Laboratory for Research in Complex Systems, Menlo Park, CA, USA.,University of California San Francisco, San Francisco, CA, USA.,San Francisco State University, San Francisco, CA, USA
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4
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Thioesterase superfamily member 1 undergoes stimulus-coupled conformational reorganization to regulate metabolism in mice. Nat Commun 2021; 12:3493. [PMID: 34108467 PMCID: PMC8190112 DOI: 10.1038/s41467-021-23595-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 04/29/2021] [Indexed: 01/21/2023] Open
Abstract
In brown adipose tissue, thermogenesis is suppressed by thioesterase superfamily member 1 (Them1), a long chain fatty acyl-CoA thioesterase. Them1 is highly upregulated by cold ambient temperature, where it reduces fatty acid availability and limits thermogenesis. Here, we show that Them1 regulates metabolism by undergoing conformational changes in response to β-adrenergic stimulation that alter Them1 intracellular distribution. Them1 forms metabolically active puncta near lipid droplets and mitochondria. Upon stimulation, Them1 is phosphorylated at the N-terminus, inhibiting puncta formation and activity and resulting in a diffuse intracellular localization. We show by correlative light and electron microscopy that Them1 puncta are biomolecular condensates that are inhibited by phosphorylation. Thus, Them1 forms intracellular biomolecular condensates that limit fatty acid oxidation and suppress thermogenesis. During a period of energy demand, the condensates are disrupted by phosphorylation to allow for maximal thermogenesis. The stimulus-coupled reorganization of Them1 provides fine-tuning of thermogenesis and energy expenditure.
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5
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Saragih SA, Takemoto S, Kusumoto D, Kamata N. Fungal diversity in the mycangium of an ambrosia beetle Xylosandrus crassiusculus (Coleoptera: Curculionidae) in Japan during their late dispersal season. Symbiosis 2021. [DOI: 10.1007/s13199-021-00762-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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6
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Remmelzwaal S, Geisler F, Stucchi R, van der Horst S, Pasolli M, Kroll JR, Jarosinska OD, Akhmanova A, Richardson CA, Altelaar M, Leube RE, Ramalho JJ, Boxem M. BBLN-1 is essential for intermediate filament organization and apical membrane morphology. Curr Biol 2021; 31:2334-2346.e9. [PMID: 33857431 DOI: 10.1016/j.cub.2021.03.069] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/25/2021] [Accepted: 03/19/2021] [Indexed: 01/07/2023]
Abstract
Epithelial tubes are essential components of metazoan organ systems that control the flow of fluids and the exchange of materials between body compartments and the outside environment. The size and shape of the central lumen confer important characteristics to tubular organs and need to be carefully controlled. Here, we identify the small coiled-coil protein BBLN-1 as a regulator of lumen morphology in the C. elegans intestine. Loss of BBLN-1 causes the formation of bubble-shaped invaginations of the apical membrane into the cytoplasm of intestinal cells and abnormal aggregation of the subapical intermediate filament (IF) network. BBLN-1 interacts with IF proteins and localizes to the IF network in an IF-dependent manner. The appearance of invaginations is a result of the abnormal IF aggregation, indicating a direct role for the IF network in maintaining lumen homeostasis. Finally, we identify bublin (BBLN) as the mammalian ortholog of BBLN-1. When expressed in the C. elegans intestine, BBLN recapitulates the localization pattern of BBLN-1 and can compensate for the loss of BBLN-1 in early larvae. In mouse intestinal organoids, BBLN localizes subapically, together with the IF protein keratin 8. Our results therefore may have implications for understanding the role of IFs in regulating epithelial tube morphology in mammals.
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Affiliation(s)
- Sanne Remmelzwaal
- Developmental Biology, Institute of Biodynamics and Biocomplexity, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Florian Geisler
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Riccardo Stucchi
- Cell Biology, Neurobiology and Biophysics, Institute of Biodynamics and Biocomplexity, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands; Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Suzanne van der Horst
- Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands; Oncode Institute, Utrecht, the Netherlands
| | - Milena Pasolli
- Cell Biology, Neurobiology and Biophysics, Institute of Biodynamics and Biocomplexity, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Jason R Kroll
- Developmental Biology, Institute of Biodynamics and Biocomplexity, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Olga D Jarosinska
- Developmental Biology, Institute of Biodynamics and Biocomplexity, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Anna Akhmanova
- Cell Biology, Neurobiology and Biophysics, Institute of Biodynamics and Biocomplexity, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | | | - Maarten Altelaar
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Rudolf E Leube
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - João J Ramalho
- Developmental Biology, Institute of Biodynamics and Biocomplexity, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands.
| | - Mike Boxem
- Developmental Biology, Institute of Biodynamics and Biocomplexity, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands.
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7
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Penfield L, Shankar R, Szentgyörgyi E, Laffitte A, Mauro MS, Audhya A, Müller-Reichert T, Bahmanyar S. Regulated lipid synthesis and LEM2/CHMP7 jointly control nuclear envelope closure. J Cell Biol 2021; 219:151636. [PMID: 32271860 PMCID: PMC7199858 DOI: 10.1083/jcb.201908179] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 01/22/2020] [Accepted: 03/03/2020] [Indexed: 11/22/2022] Open
Abstract
The nuclear permeability barrier depends on closure of nuclear envelope (NE) holes. Here, we investigate closure of the NE opening surrounding the meiotic spindle in C. elegans oocytes. ESCRT-III components accumulate at the opening but are not required for nuclear closure on their own. 3D analysis revealed cytoplasmic membranes directly adjacent to NE holes containing meiotic spindle microtubules. We demonstrate that the NE protein phosphatase, CNEP-1/CTDNEP1, controls de novo glycerolipid synthesis through lipin to prevent invasion of excess ER membranes into NE holes and a defective NE permeability barrier. Loss of NE adaptors for ESCRT-III exacerbates ER invasion and nuclear permeability defects in cnep-1 mutants, suggesting that ESCRTs restrict excess ER membranes during NE closure. Restoring glycerolipid synthesis in embryos deleted for CNEP-1 and ESCRT components rescued NE permeability defects. Thus, regulating the production and feeding of ER membranes into NE holes together with ESCRT-mediated remodeling is required for nuclear closure.
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Affiliation(s)
- Lauren Penfield
- Department of Molecular, Cellular and Developmental Biology, New Haven, CT
| | - Raakhee Shankar
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI
| | - Erik Szentgyörgyi
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Alyssa Laffitte
- Department of Molecular, Cellular and Developmental Biology, New Haven, CT
| | - Michael Sean Mauro
- Department of Molecular, Cellular and Developmental Biology, New Haven, CT
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI
| | - Thomas Müller-Reichert
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Shirin Bahmanyar
- Department of Molecular, Cellular and Developmental Biology, New Haven, CT
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8
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Otegui MS. High-Pressure Freezing and Freeze Substitution for Transmission Electron Microscopy Imaging and Immunogold-Labeling. Methods Mol Biol 2020; 2200:337-347. [PMID: 33175386 DOI: 10.1007/978-1-0716-0880-7_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2023]
Abstract
Electron microscopy enables the unbiased imaging of organelles and cellular structures at nano-meter scale resolution. The combination of cryofixation/freeze-substitution methods with other imaging techniques such as correlative light and electron microscopy (CLEM), electron tomography (ET), and immunogold-labeling provides unique opportunities to understand structural changes associated with cellular processes. This chapter presents the main steps in the preparation of Arabidopsis thaliana roots, cotyledons, anthers, and developing seeds by high-pressure freezing and freeze-substitution for structural analysis and immunogold-labeling using transmission electron microscopy.
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Affiliation(s)
- Marisa S Otegui
- Department of Botany, University of Wisconsin-Madison, Madison, WI, USA. .,Department of Genetics, University of Wisconsin-Madison, Madison, WI, USA. .,Laboratory of Molecular and Cellular Biology, University of Wisconsin-Madison, Madison, WI, USA.
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9
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Andrian T, Bakkum T, van Elsland DM, Bos E, Koster AJ, Albertazzi L, van Kasteren SI, Pujals S. Super-resolution correlative light-electron microscopy using a click-chemistry approach for studying intracellular trafficking. Methods Cell Biol 2020; 162:303-331. [PMID: 33707017 DOI: 10.1016/bs.mcb.2020.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Correlative light and electron microscopy (CLEM) entails a group of multimodal imaging techniques that are combined to pinpoint to the location of fluorescently labeled molecules in the context of their ultrastructural cellular environment. Here we describe a detailed workflow for STORM-CLEM, in which STochastic Optical Reconstruction Microscopy (STORM), an optical super-resolution technique, is correlated with transmission electron microscopy (TEM). This protocol has the advantage that both imaging modalities have resolution at the nanoscale, bringing higher synergies on the information obtained. The sample is prepared according to the Tokuyasu method followed by click-chemistry labeling and STORM imaging. Then, after heavy metal staining, electron microscopy imaging is performed followed by correlation of the two images. The case study presented here is on intracellular pathogens, but the protocol is versatile and could potentially be applied to many types of samples.
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Affiliation(s)
- Teodora Andrian
- Institute of Bioengineering of Catalonia (IBEC), Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Thomas Bakkum
- Leiden Institute of Chemistry and The Institute for Chemical Immunology, Leiden University, Leiden, The Netherlands
| | - Daphne M van Elsland
- Department of Cell and Chemical Biology, The Institute for Chemical Immunology, Leiden University Medical Center LUMC, Leiden, The Netherlands
| | - Erik Bos
- Department of Cell and Chemical Biology, Section Electron Microscopy, Leiden University Medical Center LUMC, Leiden, The Netherlands
| | - Abraham J Koster
- Department of Cell and Chemical Biology, Section Electron Microscopy, Leiden University Medical Center LUMC, Leiden, The Netherlands
| | - Lorenzo Albertazzi
- Institute of Bioengineering of Catalonia (IBEC), Barcelona Institute of Science and Technology, Barcelona, Spain; Department of Biomedical Engineering, Institute of Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands.
| | - Sander I van Kasteren
- Leiden Institute of Chemistry and The Institute for Chemical Immunology, Leiden University, Leiden, The Netherlands.
| | - Sílvia Pujals
- Institute of Bioengineering of Catalonia (IBEC), Barcelona Institute of Science and Technology, Barcelona, Spain; Department of Electronics and Biomedical Engineering, Faculty of Physics, Universitat de Barcelona, Barcelona, Spain.
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10
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Electron tomography and immunogold labeling of plant cells. Methods Cell Biol 2020; 160:21-36. [PMID: 32896317 DOI: 10.1016/bs.mcb.2020.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Electron microscopy enables the imaging of organelles and macromolecular complexes within cells at nanometer scale resolution. Electron tomography of biological samples, either in vitrified ice or fixed and embedded in resin, provides three-dimensional structural information of relatively small volumes (a few cubic microns) of cells at axial resolutions of 1-7nm. This chapter discusses approaches for plant sample preparation by high-pressure freezing/freeze-substitution and resin-embedding for electron tomography and immunogold labeling using transmission electron microscopy.
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11
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Neumann U, Hay A. Seed coat development in explosively dispersed seeds of Cardamine hirsuta. ANNALS OF BOTANY 2020; 126:39-59. [PMID: 31796954 PMCID: PMC7304473 DOI: 10.1093/aob/mcz190] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 11/22/2019] [Indexed: 05/28/2023]
Abstract
BACKGROUND AND AIMS Seeds are dispersed by explosive coiling of the fruit valves in Cardamine hirsuta. This rapid coiling launches the small seeds on ballistic trajectories to spread over a 2 m radius around the parent plant. The seed surface interacts with both the coiling fruit valve during launch and subsequently with the air during flight. We aim to identify features of the seed surface that may contribute to these interactions by characterizing seed coat differentiation. METHODS Differentiation of the outermost seed coat layers from the outer integuments of the ovule involves dramatic cellular changes that we characterize in detail at the light and electron microscopical level including immunofluorescence and immunogold labelling. KEY RESULTS We found that the two outer integument (oi) layers of the seed coat contributed differently to the topography of the seed surface in the explosively dispersed seeds of C. hirsuta vs. the related species Arabidopsis thaliana where seed dispersal is non-explosive. The surface of A. thaliana seeds is shaped by the columella and the anticlinal cell walls of the epidermal oi2 layer. In contrast, the surface of C. hirsuta seeds is shaped by a network of prominent ridges formed by the anticlinal walls of asymmetrically thickened cells of the sub-epidermal oi1 layer, especially at the seed margin. Both the oi2 and oi1 cell layers in C. hirsuta seeds are characterized by specialized, pectin-rich cell walls that are deposited asymmetrically in the cell. CONCLUSIONS The two outermost seed coat layers in C. hirsuta have distinct properties: the sub-epidermal oi1 layer determines the topography of the seed surface, while the epidermal oi2 layer accumulates mucilage. These properties are influenced by polar deposition of distinct pectin polysaccharides in the cell wall. Although the ridged seed surface formed by oi1 cell walls is associated with ballistic dispersal in C. hirsuta, it is not restricted to explosively dispersed seeds in the Brassicaceae.
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Affiliation(s)
- Ulla Neumann
- Max Planck Institute for Plant Breeding Research, Köln, Germany
| | - Angela Hay
- Max Planck Institute for Plant Breeding Research, Köln, Germany
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12
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Brunet T, Larson BT, Linden TA, Vermeij MJA, McDonald K, King N. Light-regulated collective contractility in a multicellular choanoflagellate. Science 2020; 366:326-334. [PMID: 31624206 DOI: 10.1126/science.aay2346] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/16/2019] [Indexed: 12/11/2022]
Abstract
Collective cell contractions that generate global tissue deformations are a signature feature of animal movement and morphogenesis. However, the origin of collective contractility in animals remains unclear. While surveying the Caribbean island of Curaçao for choanoflagellates, the closest living relatives of animals, we isolated a previously undescribed species (here named Choanoeca flexa sp. nov.) that forms multicellular cup-shaped colonies. The colonies rapidly invert their curvature in response to changing light levels, which they detect through a rhodopsin-cyclic guanosine monophosphate pathway. Inversion requires actomyosin-mediated apical contractility and allows alternation between feeding and swimming behavior. C. flexa thus rapidly converts sensory inputs directly into multicellular contractions. These findings may inform reconstructions of hypothesized animal ancestors that existed before the evolution of specialized sensory and contractile cells.
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Affiliation(s)
- Thibaut Brunet
- Howard Hughes Medical Institute and the Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Ben T Larson
- Howard Hughes Medical Institute and the Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.,Biophysics Graduate Group, University of California, Berkeley, CA, USA
| | - Tess A Linden
- Howard Hughes Medical Institute and the Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Mark J A Vermeij
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, CARMABI, Piscaderabaai z/n Willemstad, Curaçao
| | - Kent McDonald
- Electron Microscopy Laboratory, University of California, Berkeley, CA, USA
| | - Nicole King
- Howard Hughes Medical Institute and the Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
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13
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Qian X, Santini C, Kosta A, Menguy N, Le Guenno H, Zhang W, Li J, Chen Y, Liu J, Alberto F, Espinosa L, Xiao T, Wu L. Juxtaposed membranes underpin cellular adhesion and display unilateral cell division of multicellular magnetotactic prokaryotes. Environ Microbiol 2020; 22:1481-1494. [DOI: 10.1111/1462-2920.14710] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 06/09/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Xin‐Xin Qian
- Aix Marseille University, CNRS, LCB Marseille 13402 France
- International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms (LIA‐MagMC), CNRS‐CAS Marseille 13402 France
| | - Claire‐Lise Santini
- Aix Marseille University, CNRS, LCB Marseille 13402 France
- International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms (LIA‐MagMC), CNRS‐CAS Marseille 13402 France
| | - Artemis Kosta
- Microscopy Core Facility, FR3479 IMM, CNRS, Aix Marseille University Marseille France
| | - Nicolas Menguy
- International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms (LIA‐MagMC), CNRS‐CAS Marseille 13402 France
- Sorbonne Université, UMR CNRS 7590, Muséum National d'Histoire Naturelle, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC 75005 Paris France
| | - Hugo Le Guenno
- Microscopy Core Facility, FR3479 IMM, CNRS, Aix Marseille University Marseille France
| | - Wenyan Zhang
- International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms (LIA‐MagMC), CNRS‐CAS Marseille 13402 France
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences Qingdao 266071 China
| | - Jinhua Li
- International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms (LIA‐MagMC), CNRS‐CAS Marseille 13402 France
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences Beijing 100029 China
| | - Yi‐Ran Chen
- International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms (LIA‐MagMC), CNRS‐CAS Marseille 13402 France
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences Qingdao 266071 China
| | - Jia Liu
- International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms (LIA‐MagMC), CNRS‐CAS Marseille 13402 France
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences Qingdao 266071 China
| | - François Alberto
- Aix Marseille University, CNRS, LCB Marseille 13402 France
- International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms (LIA‐MagMC), CNRS‐CAS Marseille 13402 France
| | - Leon Espinosa
- Aix Marseille University, CNRS, LCB Marseille 13402 France
| | - Tian Xiao
- International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms (LIA‐MagMC), CNRS‐CAS Marseille 13402 France
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences Qingdao 266071 China
| | - Long‐Fei Wu
- Aix Marseille University, CNRS, LCB Marseille 13402 France
- International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms (LIA‐MagMC), CNRS‐CAS Marseille 13402 France
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14
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Amstutz CL, Fristedt R, Schultink A, Merchant SS, Niyogi KK, Malnoë A. An atypical short-chain dehydrogenase-reductase functions in the relaxation of photoprotective qH in Arabidopsis. NATURE PLANTS 2020; 6:154-166. [PMID: 32055052 PMCID: PMC7288749 DOI: 10.1038/s41477-020-0591-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 12/28/2019] [Indexed: 05/20/2023]
Abstract
Photosynthetic organisms experience wide fluctuations in light intensity and regulate light harvesting accordingly to prevent damage from excess energy. The antenna quenching component qH is a sustained form of energy dissipation that protects the photosynthetic apparatus under stress conditions. This photoprotective mechanism requires the plastid lipocalin LCNP and is prevented by SUPPRESSOR OF QUENCHING1 (SOQ1) under non-stress conditions. However, the molecular mechanism of qH relaxation has yet to be resolved. Here, we isolated and characterized RELAXATION OF QH1 (ROQH1), an atypical short-chain dehydrogenase-reductase that functions as a qH-relaxation factor in Arabidopsis. The ROQH1 gene belongs to the GreenCut2 inventory specific to photosynthetic organisms, and the ROQH1 protein localizes to the chloroplast stroma lamellae membrane. After a cold and high-light treatment, qH does not relax in roqh1 mutants and qH does not occur in leaves overexpressing ROQH1. When the soq1 and roqh1 mutations are combined, qH can neither be prevented nor relaxed and soq1 roqh1 displays constitutive qH and light-limited growth. We propose that LCNP and ROQH1 perform dosage-dependent, antagonistic functions to protect the photosynthetic apparatus and maintain light-harvesting efficiency in plants.
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Affiliation(s)
- Cynthia L Amstutz
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Rikard Fristedt
- Department of Physics and Astronomy, Vrije University of Amsterdam, Amsterdam, The Netherlands
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Alex Schultink
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Sabeeha S Merchant
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
- Institute for Genomics and Proteomics, University of California, Los Angeles, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Krishna K Niyogi
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA.
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Alizée Malnoë
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA.
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden.
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15
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Horizontal acquisition of a patchwork Calvin cycle by symbiotic and free-living Campylobacterota (formerly Epsilonproteobacteria). ISME JOURNAL 2019; 14:104-122. [PMID: 31562384 PMCID: PMC6908604 DOI: 10.1038/s41396-019-0508-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 08/06/2019] [Accepted: 08/15/2019] [Indexed: 11/30/2022]
Abstract
Most autotrophs use the Calvin–Benson–Bassham (CBB) cycle for carbon fixation. In contrast, all currently described autotrophs from the Campylobacterota (previously Epsilonproteobacteria) use the reductive tricarboxylic acid cycle (rTCA) instead. We discovered campylobacterotal epibionts (“Candidatus Thiobarba”) of deep-sea mussels that have acquired a complete CBB cycle and may have lost most key genes of the rTCA cycle. Intriguingly, the phylogenies of campylobacterotal CBB cycle genes suggest they were acquired in multiple transfers from Gammaproteobacteria closely related to sulfur-oxidizing endosymbionts associated with the mussels, as well as from Betaproteobacteria. We hypothesize that “Ca. Thiobarba” switched from the rTCA cycle to a fully functional CBB cycle during its evolution, by acquiring genes from multiple sources, including co-occurring symbionts. We also found key CBB cycle genes in free-living Campylobacterota, suggesting that the CBB cycle may be more widespread in this phylum than previously known. Metatranscriptomics and metaproteomics confirmed high expression of CBB cycle genes in mussel-associated “Ca. Thiobarba”. Direct stable isotope fingerprinting showed that “Ca. Thiobarba” has typical CBB signatures, suggesting that it uses this cycle for carbon fixation. Our discovery calls into question current assumptions about the distribution of carbon fixation pathways in microbial lineages, and the interpretation of stable isotope measurements in the environment.
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16
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Gruber-Vodicka HR, Leisch N, Kleiner M, Hinzke T, Liebeke M, McFall-Ngai M, Hadfield MG, Dubilier N. Two intracellular and cell type-specific bacterial symbionts in the placozoan Trichoplax H2. Nat Microbiol 2019; 4:1465-1474. [PMID: 31182796 PMCID: PMC6784892 DOI: 10.1038/s41564-019-0475-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 04/26/2019] [Indexed: 02/02/2023]
Abstract
Placozoa is an enigmatic phylum of simple, microscopic, marine metazoans1,2. Although intracellular bacteria have been found in all members of this phylum, almost nothing is known about their identity, location and interactions with their host3–6. We used metagenomic and metatranscriptomic sequencing of single host individuals, plus metaproteomic and imaging analyses, to show that the placozoan Trichoplax sp. H2 lives in symbiosis with two intracellular bacteria. One symbiont forms an undescribed genus in the Midichloriaceae (Rickettsiales)7,8 and has a genomic repertoire similar to that of rickettsial parasites9,10, but does not seem to express key genes for energy parasitism. Correlative image analyses and three-dimensional electron tomography revealed that this symbiont resides in the rough endoplasmic reticulum of its host’s internal fibre cells. The second symbiont belongs to the Margulisbacteria, a phylum without cultured representatives and not known to form intracellular associations11–13. This symbiont lives in the ventral epithelial cells of Trichoplax, probably metabolizes algal lipids digested by its host and has the capacity to supplement the placozoan’s nutrition. Our study shows that one of the simplest animals has evolved highly specific and intimate associations with symbiotic, intracellular bacteria and highlights that symbioses can provide access to otherwise elusive microbial dark matter. Using a multi-omics approach, together with imaging analyses, the authors characterize the two intracellular bacterial symbionts of Trichoplax, one of the simplest animals.
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Affiliation(s)
| | - Nikolaus Leisch
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Manuel Kleiner
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, USA
| | - Tjorven Hinzke
- Department of Pharmaceutical Biotechnology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology, Greifswald, Germany.,Department of Geoscience, University of Calgary, Calgary, Alberta, Canada
| | - Manuel Liebeke
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Margaret McFall-Ngai
- Kewalo Marine Laboratory, Pacific Biosciences Research Center, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Michael G Hadfield
- Kewalo Marine Laboratory, Pacific Biosciences Research Center, University of Hawai'i at Mānoa, Honolulu, HI, USA.
| | - Nicole Dubilier
- Max Planck Institute for Marine Microbiology, Bremen, Germany.
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17
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Jensen EL, Clement R, Kosta A, Maberly SC, Gontero B. A new widespread subclass of carbonic anhydrase in marine phytoplankton. ISME JOURNAL 2019; 13:2094-2106. [PMID: 31024153 PMCID: PMC6776030 DOI: 10.1038/s41396-019-0426-8] [Citation(s) in RCA: 129] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/28/2019] [Accepted: 03/30/2019] [Indexed: 11/09/2022]
Abstract
Most aquatic photoautotrophs depend on CO2-concentrating mechanisms (CCMs) to maintain productivity at ambient concentrations of CO2, and carbonic anhydrase (CA) plays a key role in these processes. Here we present different lines of evidence showing that the protein LCIP63, identified in the marine diatom Thalassiosira pseudonana, is a CA. However, sequence analysis showed that it has a low identity with any known CA and therefore belongs to a new subclass that we designate as iota-CA. Moreover, LCIP63 unusually prefers Mn2+ to Zn2+ as a cofactor, which is potentially of ecological relevance since Mn2+ is more abundant than Zn2+ in the ocean. LCIP63 is located in the chloroplast and only expressed at low concentrations of CO2. When overexpressed using biolistic transformation, the rate of photosynthesis at limiting concentrations of dissolved inorganic carbon increased, confirming its role in the CCM. LCIP63 homologs are present in the five other sequenced diatoms and in other algae, bacteria, and archaea. Thus LCIP63 is phylogenetically widespread but overlooked. Analysis of the Tara Oceans database confirmed this and showed that LCIP63 is widely distributed in marine environments and is therefore likely to play an important role in global biogeochemical carbon cycling.
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Affiliation(s)
- Erik L Jensen
- Aix Marseille Univ, CNRS, BIP, UMR 7281, IMM, FR3479, 31 Chemin J. Aiguier, 13402, Marseille Cedex 20, France
| | - Romain Clement
- Aix Marseille Univ, CNRS, BIP, UMR 7281, IMM, FR3479, 31 Chemin J. Aiguier, 13402, Marseille Cedex 20, France
| | - Artemis Kosta
- Microscopy Core Facility, Aix Marseille Univ, CNRS, IMM, FR3479, 31 Chemin J. Aiguier, 13402, Marseille Cedex 20, France
| | - Stephen C Maberly
- Lake Ecosystems Group, Centre for Ecology & Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP, UK
| | - Brigitte Gontero
- Aix Marseille Univ, CNRS, BIP, UMR 7281, IMM, FR3479, 31 Chemin J. Aiguier, 13402, Marseille Cedex 20, France.
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18
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Fuchs J, Mueller M, Daxböck C, Stückler M, Lang I, Leitinger G, Bock E, El-Heliebi A, Moser G, Glasmacher B, Brislinger D. Histological processing of un-/cellularized thermosensitive electrospun scaffolds. Histochem Cell Biol 2018; 151:343-356. [PMID: 30560287 PMCID: PMC6469612 DOI: 10.1007/s00418-018-1757-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2018] [Indexed: 11/28/2022]
Abstract
Histological processing of thermosensitive electrospun poly(ε-caprolactone)/poly(l-lactide) (PCL/PLA) scaffolds fails, as poly(ε-caprolactone) (PCL) is characterized by its low-melting temperature (Tm = 60 °C). Here, we present an optimized low-temperature preparation method for the histological processing of un-/cellularized thermosensitive PCL/PLA scaffolds. Our study is aimed at the establishment of an optimized dehydration and low-melting-point paraffin-embedding method of electrospun PCL/PLA scaffolds (un-/cellularized). Furthermore, we compared this method with (a) automatized dehydration and standard paraffin embedding, (b) gelatin embedding followed by automatized dehydration and standard paraffin embedding, (c) cryofixation, and (d) acrylic resin embedding methods. We investigated pepsin and proteinase K antigen retrieval for their efficiency in epitope demasking at low temperatures and evaluated protocols for immunohistochemistry and immunofluorescence for cytokeratin 7 (CK7) and in situ padlock probe technology for beta actin (ACTB). Optimized dehydration and low-melting-point paraffin embedding preserved the PCL/PLA scaffold, as the diameter and structure of its fibers were unchanged. Cells attached to the PCL/PLA scaffolds showed limited alterations in size and morphology compared to control. Epitope demasking by enzymatic pepsin digestion and immunostaining of CK7 displayed an invasion of attached cells into the scaffold. Expression of ACTB and CK7 was shown by a combination of mRNA-based in situ padlock probe technology and immunofluorescence. In contrast, gelatin stabilization followed by standard paraffin embedding led to an overall shrinkage and melting of fibers, and therefore, no further analysis was possible. Acrylic resin embedding and cyrofixation caused fiber structures that were nearly unchanged in size and diameter. However, acrylic resin-embedded scaffolds are limited to 3 µm sections, whereas cyrofixation led to a reduction of the cell size by 14% compared to low-melting paraffin embedding. The combination of low-melting-point paraffin embedding and pepsin digestion as an antigen retrieval method offers a successful opportunity for histological investigations in thermosensitive specimens.
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Affiliation(s)
- Julia Fuchs
- Department of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010, Graz, Austria
| | - Marc Mueller
- Institute for Multiphase Processes, Leibniz University Hannover, Callinstraße 36, 30167, Hannover, Germany
| | - Christine Daxböck
- Department of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010, Graz, Austria
| | - Manuela Stückler
- Department of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010, Graz, Austria
| | - Ingrid Lang
- Department of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010, Graz, Austria
| | - Gerd Leitinger
- Department of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010, Graz, Austria
| | - Elisabeth Bock
- Department of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010, Graz, Austria
| | - Amin El-Heliebi
- Department of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010, Graz, Austria
| | - Gerit Moser
- Department of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010, Graz, Austria
| | - Birgit Glasmacher
- Institute for Multiphase Processes, Leibniz University Hannover, Callinstraße 36, 30167, Hannover, Germany
| | - Dagmar Brislinger
- Department of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010, Graz, Austria.
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19
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Santarella-Mellwig R, Haselmann U, Schieber NL, Walther P, Schwab Y, Antony C, Bartenschlager R, Romero-Brey I. Correlative Light Electron Microscopy (CLEM) for Tracking and Imaging Viral Protein Associated Structures in Cryo-immobilized Cells. J Vis Exp 2018. [PMID: 30247481 PMCID: PMC6235138 DOI: 10.3791/58154] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Due to its high resolution, electron microscopy (EM) is an indispensable tool for virologists. However, one of the main difficulties when analyzing virus-infected or transfected cells via EM are the low efficiencies of infection or transfection, hindering the examination of these cells. In order to overcome this difficulty, light microscopy (LM) can be performed first to allocate the subpopulation of infected or transfected cells. Thus, taking advantage of the use of fluorescent proteins (FPs) fused to viral proteins, LM is used here to record the positions of the "positive-transfected" cells, expressing a FP and growing on a support with an alphanumeric pattern. Subsequently, cells are further processed for EM via high pressure freezing (HPF), freeze substitution (FS) and resin embedding. The ultra-rapid freezing step ensures excellent membrane preservation of the selected cells that can then be analyzed at the ultrastructural level by transmission electron microscopy (TEM). Here, a step-by-step correlative light electron microscopy (CLEM) workflow is provided, describing sample preparation, imaging and correlation in detail. The experimental design can be also applied to address many cell biology questions.
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Affiliation(s)
| | - Uta Haselmann
- Department of Infectious Diseases, Molecular Virology, Heidelberg University
| | | | - Paul Walther
- Central Facility for Electron Microscopy, Ulm University
| | | | | | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, Heidelberg University; Heidelberg Partner Site, German Center for Infection Research;
| | - Inés Romero-Brey
- Department of Infectious Diseases, Molecular Virology, Heidelberg University;
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20
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Reipert S, Goldammer H, Richardson C, Goldberg MW, Hawkins TJ, Hollergschwandtner E, Kaufmann WA, Antreich S, Stierhof YD. Agitation Modules: Flexible Means to Accelerate Automated Freeze Substitution. J Histochem Cytochem 2018; 66:903-921. [PMID: 29969056 DOI: 10.1369/0022155418786698] [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] [Indexed: 12/14/2022] Open
Abstract
For ultrafast fixation of biological samples to avoid artifacts, high-pressure freezing (HPF) followed by freeze substitution (FS) is preferred over chemical fixation at room temperature. After HPF, samples are maintained at low temperature during dehydration and fixation, while avoiding damaging recrystallization. This is a notoriously slow process. McDonald and Webb demonstrated, in 2011, that sample agitation during FS dramatically reduces the necessary time. Then, in 2015, we (H.G. and S.R.) introduced an agitation module into the cryochamber of an automated FS unit and demonstrated that the preparation of algae could be shortened from days to a couple of hours. We argued that variability in the processing, reproducibility, and safety issues are better addressed using automated FS units. For dissemination, we started low-cost manufacturing of agitation modules for two of the most widely used FS units, the Automatic Freeze Substitution Systems, AFS(1) and AFS2, from Leica Microsystems, using three dimensional (3D)-printing of the major components. To test them, several labs independently used the modules on a wide variety of specimens that had previously been processed by manual agitation, or without agitation. We demonstrate that automated processing with sample agitation saves time, increases flexibility with respect to sample requirements and protocols, and produces data of at least as good quality as other approaches.
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Affiliation(s)
- Siegfried Reipert
- Core Facility Cell Imaging and Ultrastructure Research, University of Vienna, Vienna, Austria
| | - Helmuth Goldammer
- Core Facility Cell Imaging and Ultrastructure Research, University of Vienna, Vienna, Austria
| | | | - Martin W Goldberg
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Timothy J Hawkins
- Department of Biosciences, Durham University, Durham, United Kingdom
| | | | - Walter A Kaufmann
- Electron Microscopy Facility, Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Sebastian Antreich
- Core Facility Cell Imaging and Ultrastructure Research, University of Vienna, Vienna, Austria
| | - York-Dieter Stierhof
- Center for Plant Molecular Biology (ZMBP), Microscopy, University of Tübingen, Tübingen, Germany
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21
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Burel A, Lavault MT, Chevalier C, Gnaegi H, Prigent S, Mucciolo A, Dutertre S, Humbel BM, Guillaudeux T, Kolotuev I. A targeted 3D EM and correlative microscopy method using SEM array tomography. Development 2018; 145:dev.160879. [PMID: 29802150 DOI: 10.1242/dev.160879] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 05/16/2018] [Indexed: 12/15/2022]
Abstract
Using electron microscopy to localize rare cellular events or structures in complex tissue is challenging. Correlative light and electron microscopy procedures have been developed to link fluorescent protein expression with ultrastructural resolution. Here, we present an optimized scanning electron microscopy (SEM) workflow for volumetric array tomography for asymmetric samples and model organisms (Caenorhabditis elegans, Drosophila melanogaster, Danio rerio). We modified a diamond knife to simplify serial section array acquisition with minimal artifacts. After array acquisition, the arrays were transferred to a glass coverslip or silicon wafer support. Using light microscopy, the arrays were screened rapidly for initial recognition of global anatomical features (organs or body traits). Then, using SEM, an in-depth study of the cells and/or organs of interest was performed. Our manual and automatic data acquisition strategies make 3D data acquisition and correlation simpler and more precise than alternative methods. This method can be used to address questions in cell and developmental biology that require the efficient identification of a labeled cell or organelle.
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Affiliation(s)
- Agnes Burel
- University of Rennes 1, UMS Biosit, MRic, 35043 Rennes, France
| | | | | | | | - Sylvain Prigent
- University of Rennes 1, UMS Biosit, MRic, 35043 Rennes, France
| | - Antonio Mucciolo
- University of Lausanne, Faculté de biologie et de médecine, Electron Microscopy Facility, CH-1015 Lausanne, Switzerland
| | | | - Bruno M Humbel
- University of Lausanne, Faculté de biologie et de médecine, Electron Microscopy Facility, CH-1015 Lausanne, Switzerland
| | | | - Irina Kolotuev
- University of Rennes 1, UMS Biosit, MRic, 35043 Rennes, France .,University of Lausanne, Faculté de biologie et de médecine, Electron Microscopy Facility, CH-1015 Lausanne, Switzerland
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22
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Cano-Garrido O, Garcia-Fruitós E, Villaverde A, Sánchez-Chardi A. Improving Biomaterials Imaging for Nanotechnology: Rapid Methods for Protein Localization at Ultrastructural Level. Biotechnol J 2018; 13:e1700388. [PMID: 29271611 DOI: 10.1002/biot.201700388] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 12/07/2017] [Indexed: 11/06/2022]
Abstract
The preparation of biological samples for electron microscopy is material- and time-consuming because it is often based on long protocols that also may produce artifacts. Protein labeling for transmission electron microscopy (TEM) is such an example, taking several days. However, for protein-based nanotechnology, high resolution imaging techniques are unique and crucial tools for studying the spatial distribution of these molecules, either alone or as components of biomaterials. In this paper, we tested two new short methods of immunolocalization for TEM, and compared them with a standard protocol in qualitative and quantitative approaches by using four protein-based nanoparticles. We reported a significant increase of labeling per area of nanoparticle in both new methodologies (H = 19.811; p < 0.001) with all the model antigens tested: GFP (H = 22.115; p < 0.001), MMP-2 (H = 19.579; p < 0.001), MMP-9 (H = 7.567; p < 0.023), and IFN-γ (H = 62.110; p < 0.001). We also found that the most suitable protocol for labeling depends on the nanoparticle's tendency to aggregate. Moreover, the shorter methods reduce artifacts, time (by 30%), residues, and reagents hindering, losing, or altering antigens, and obtaining a significant increase of protein localization (of about 200%). Overall, this study makes a step forward in the development of optimized protocols for the nanoscale localization of peptides and proteins within new biomaterials.
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Affiliation(s)
- Olivia Cano-Garrido
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain.,Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain.,CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN)
| | - Elena Garcia-Fruitós
- Departament de Producció de Remugants, Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Caldes de Montbui 08140, Spain
| | - Antonio Villaverde
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain.,Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain.,CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN)
| | - Alejandro Sánchez-Chardi
- Servei de Microscòpia, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain
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23
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Frankel EB, Shankar R, Moresco JJ, Yates JR, Volkmann N, Audhya A. Ist1 regulates ESCRT-III assembly and function during multivesicular endosome biogenesis in Caenorhabditis elegans embryos. Nat Commun 2017; 8:1439. [PMID: 29129923 PMCID: PMC5682282 DOI: 10.1038/s41467-017-01636-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 10/03/2017] [Indexed: 12/23/2022] Open
Abstract
Degradation of most integral membrane proteins is directed by the endosomal sorting complex required for transport (ESCRT) machinery, which selectively targets ubiquitin-modified cargoes into intralumenal vesicles (ILVs) within multivesicular endosomes (MVEs). To better understand the mechanisms underlying ESCRT-mediated formation of ILVs, we exploited the rapid, de novo biogenesis of MVEs during the oocyte-to-embryo transition in C. elegans. In contrast to previous models suggesting that ILVs form individually, we demonstrate that they remain tethered to one another subsequent to internalization, arguing that they bud continuously from stable subdomains. In addition, we show that membrane bending and ILV formation are directed specifically by the ESCRT-III complex in vivo in a manner regulated by Ist1, which promotes ESCRT-III assembly and inhibits the incorporation of upstream ESCRT components into ILVs. Our findings underscore essential actions for ESCRT-III in membrane remodeling, cargo selection, and cargo retention, which act repetitively to maximize the rate of ILV formation.
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Affiliation(s)
- E B Frankel
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, 440 Henry Mall, Madison, WI, 53706, USA
| | - Raakhee Shankar
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, 440 Henry Mall, Madison, WI, 53706, USA
| | - James J Moresco
- The Scripps Research Institute, 10550 North Torrey Pines Rd., Department of Chemical Physiology, La Jolla, CA, 92037, USA
| | - John R Yates
- The Scripps Research Institute, 10550 North Torrey Pines Rd., Department of Chemical Physiology, La Jolla, CA, 92037, USA
| | - Niels Volkmann
- Bioinformatics and Structural Biology Program, Sanford-Burnham Medical Research Institute, 10901N Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, 440 Henry Mall, Madison, WI, 53706, USA.
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24
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Zhou H, Gang Y, Chen S, Wang Y, Xiong Y, Li L, Yin F, Liu Y, Liu X, Zeng S. Development of a neutral embedding resin for optical imaging of fluorescently labeled biological tissue. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-7. [PMID: 29076308 DOI: 10.1117/1.jbo.22.10.106015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 10/02/2017] [Indexed: 06/07/2023]
Abstract
Plastic embedding is widely applied in light microscopy analyses. Previous studies have shown that embedding agents and related techniques can greatly affect the quality of biological tissue embedding and fluorescent imaging. Specifically, it is difficult to preserve endogenous fluorescence using currently available acidic commercial embedding resins and related embedding techniques directly. Here, we developed a neutral embedding resin that improved the green fluorescent protein (GFP), yellow fluorescent protein (YFP), and DsRed fluorescent intensity without adjusting the pH value of monomers or reactivating fluorescence in lye. The embedding resin had a high degree of polymerization, and its fluorescence preservation ratios for GFP, YFP, and DsRed were 126.5%, 155.8%, and 218.4%, respectively.
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Affiliation(s)
- Hongfu Zhou
- Huazhong University of Science and Technology, Collaborative Innovation Center for Biomedical Engine, China
- Huazhong University of Science and Technology, School of Engineering Sciences, Britton Chance Center, China
| | - Yadong Gang
- Huazhong University of Science and Technology, Collaborative Innovation Center for Biomedical Engine, China
- Huazhong University of Science and Technology, School of Engineering Sciences, Britton Chance Center, China
| | - Shenghua Chen
- Huazhong University of Science and Technology, Collaborative Innovation Center for Biomedical Engine, China
- Huazhong University of Science and Technology, School of Engineering Sciences, Britton Chance Center, China
| | - Yu Wang
- Huazhong University of Science and Technology, Collaborative Innovation Center for Biomedical Engine, China
- Huazhong University of Science and Technology, School of Engineering Sciences, Britton Chance Center, China
| | - Yumiao Xiong
- Huazhong University of Science and Technology, Collaborative Innovation Center for Biomedical Engine, China
- Huazhong University of Science and Technology, School of Engineering Sciences, Britton Chance Center, China
| | - Longhui Li
- Huazhong University of Science and Technology, Collaborative Innovation Center for Biomedical Engine, China
- Huazhong University of Science and Technology, School of Engineering Sciences, Britton Chance Center, China
| | - Fangfang Yin
- Huazhong University of Science and Technology, Collaborative Innovation Center for Biomedical Engine, China
- Huazhong University of Science and Technology, School of Engineering Sciences, Britton Chance Center, China
| | - Yue Liu
- Huazhong University of Science and Technology, Collaborative Innovation Center for Biomedical Engine, China
- Huazhong University of Science and Technology, School of Engineering Sciences, Britton Chance Center, China
| | - Xiuli Liu
- Huazhong University of Science and Technology, Collaborative Innovation Center for Biomedical Engine, China
- Huazhong University of Science and Technology, School of Engineering Sciences, Britton Chance Center, China
| | - Shaoqun Zeng
- Huazhong University of Science and Technology, Collaborative Innovation Center for Biomedical Engine, China
- Huazhong University of Science and Technology, School of Engineering Sciences, Britton Chance Center, China
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25
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Rog O, Köhler S, Dernburg AF. The synaptonemal complex has liquid crystalline properties and spatially regulates meiotic recombination factors. eLife 2017; 6. [PMID: 28045371 PMCID: PMC5268736 DOI: 10.7554/elife.21455] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 01/02/2017] [Indexed: 12/27/2022] Open
Abstract
The synaptonemal complex (SC) is a polymer that spans ~100 nm between paired homologous chromosomes during meiosis. Its striated, periodic appearance in electron micrographs led to the idea that transverse filaments within this structure ‘crosslink’ the axes of homologous chromosomes, stabilizing their pairing. SC proteins can also form polycomplexes, three-dimensional lattices that recapitulate the periodic structure of SCs but do not associate with chromosomes. Here we provide evidence that SCs and polycomplexes contain mobile subunits and that their assembly is promoted by weak hydrophobic interactions, indicative of a liquid crystalline phase. We further show that in the absence of recombination intermediates, polycomplexes recapitulate the dynamic localization of pro-crossover factors during meiotic progression, revealing how the SC might act as a conduit to regulate chromosome-wide crossover distribution. Properties unique to liquid crystals likely enable long-range signal transduction along meiotic chromosomes and underlie the rapid evolution of SC proteins. DOI:http://dx.doi.org/10.7554/eLife.21455.001 The genetic information in cells is encoded within long molecules of DNA called chromosomes. In most human cells, the two copies of each chromosome – the one inherited from our mother and the one from our father – are physically separated and behave independently. However, in the reproductive cells that give rise to eggs or sperm, each chromosome must pair with its partner. Pairing first occurs at one or more positions along each chromosome. This triggers a protein-based polymer called the “synaptonemal complex” to assemble between the paired chromosomes, and then spread along the interface between the partners until they are fully lined up side-by-side. Chromosomes in reproductive cells must pair in this particular way to exchange genetic information and generate new combinations of traits. The synaptonemal complex was first observed over 60 years ago, but it remains enigmatic. Though its structure is highly ordered and looks very similar in different organisms from yeast to humans, little is known about how this polymer forms or what it does between chromosomes. Some evidence has suggested that the synaptonemal complex helps to regulate how much information can be transferred between each pair of chromosomes, but not all studies have supported this conclusion. Several lines of evidence suggest that the synaptonemal complex might be fundamentally different from other protein-based polymers, such as those that form filamentous skeletal structures within cells, namely actin filaments and microtubules. Now, Rog et al. have tested the idea that the synaptonemal complex might actually have liquid-like properties, despite its highly ordered appearance. The experiments showed that the proteins that make up the synaptonemal complex in yeast, worms and fruit flies are weakly bound to each other and can move around within the assembled structure. These are considered to be defining properties that distinguish liquids from solid materials. Together with its regular, repetitive organization, these findings indicate that the synaptonemal complex behaves like a liquid crystal. This intriguing class of materials has properties between those of conventional liquids and those of solid crystals, and is particularly sensitive to environmental conditions. Rog et al. believe that this discovery helps to explain how signals are transmitted along the length of chromosomes to regulate the transfer of genetic information. In support of this idea, further experiments showed that proteins that are required for this recombination process were also found within the synaptonemal complex. As reproductive cells transition from one stage of their development to the next, these proteins abruptly move to a new location, indicating that a switch-like signal rapidly spreads throughout the synaptonemal complex. Together the findings suggest that the liquid crystal-like properties of the synaptonemal complex allow signals to be transmitted along the interface between pairs of chromosomes. The next challenges are to understand what triggers these signals and to explore whether they are based upon physical or chemical changes within the synaptonemal complex. Further research is also needed to uncover how this information is propagated along the length of a chromosome. DOI:http://dx.doi.org/10.7554/eLife.21455.002
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Affiliation(s)
- Ofer Rog
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States.,Department of Biology, University of Utah, Salt Lake City, USA
| | - Simone Köhler
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Abby F Dernburg
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, United States.,California Institute for Quantitative Biosciences, Berkeley, United States
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26
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Claeys M, Yushin VV, Leunissen JL, Claeys J, Bert W. Self-Pressurised Rapid Freezing (SPRF): an easy-to-use and low-cost alternative cryo-fixation method for nematodes. NEMATOLOGY 2017. [DOI: 10.1163/15685411-00003093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Self-Pressurised Rapid Freezing (SPRF), an easy-to-use and low-cost alternative cryo-fixation method, was evaluated based on a comparative analysis of the ultrastructure of spermatozoa of the nematodes Acrobeles complexus and Caenorhabditis elegans. Sealed copper tubes, packed with active nematodes in water, were plunged into nitrogen slush, a semi-solid form of nitrogen. The water inside the capillary copper tube expands upon cooling due to the formation of hexagonal ice, thereby generating high pressure intrinsically for cryo-fixation of the sample. For sperm cells cryo-fixed by SPRF, the preservation of the ultrastructure was comparable to that achieved with high pressure freezing. This was evidenced by the clear details in mitochondria, membranous organelles and cytoskeleton in the pseudopod. It was demonstrated that SPRF fixation did not destroy antigenicity, based on the results of the immunolocalisation of the major sperm protein in both species. In conclusion, SPRF is a low-cost alternative cryo-fixation method for nematodes.
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Affiliation(s)
- Myriam Claeys
- Nematology Research Unit, Department of Biology, Ghent University, Belgium
| | - Vladimir V. Yushin
- National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok 690041, Russia
- Far Eastern Federal University, Vladivostok 690950, Russia
| | | | - Jef Claeys
- Nematology Research Unit, Department of Biology, Ghent University, Belgium
| | - Wim Bert
- Nematology Research Unit, Department of Biology, Ghent University, Belgium
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27
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van Lis R, Popek M, Couté Y, Kosta A, Drapier D, Nitschke W, Atteia A. Concerted Up-regulation of Aldehyde/Alcohol Dehydrogenase (ADHE) and Starch in Chlamydomonas reinhardtii Increases Survival under Dark Anoxia. J Biol Chem 2016; 292:2395-2410. [PMID: 28007962 DOI: 10.1074/jbc.m116.766048] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 12/21/2016] [Indexed: 11/06/2022] Open
Abstract
Aldehyde/alcohol dehydrogenases (ADHEs) are bifunctional enzymes that commonly produce ethanol from acetyl-CoA with acetaldehyde as intermediate and play a key role in anaerobic redox balance in many fermenting bacteria. ADHEs are also present in photosynthetic unicellular eukaryotes, where their physiological role and regulation are, however, largely unknown. Herein we provide the first molecular and enzymatic characterization of the ADHE from the photosynthetic microalga Chlamydomonas reinhardtii Purified recombinant ADHE catalyzed the reversible NADH-mediated interconversions of acetyl-CoA, acetaldehyde, and ethanol but seemed to be poised toward the production of ethanol from acetaldehyde. Phylogenetic analysis of the algal fermentative enzyme supports a vertical inheritance from a cyanobacterial-related ancestor. ADHE was located in the chloroplast, where it associated in dimers and higher order oligomers. Electron microscopy analysis of ADHE-enriched stromal fractions revealed fine spiral structures, similar to bacterial ADHE spirosomes. Protein blots showed that ADHE is regulated under oxic conditions. Up-regulation is observed in cells exposed to diverse physiological stresses, including zinc deficiency, nitrogen starvation, and inhibition of carbon concentration/fixation capacity. Analyses of the overall proteome and fermentation profiles revealed that cells with increased ADHE abundance exhibit better survival under dark anoxia. This likely relates to the fact that greater ADHE abundance appeared to coincide with enhanced starch accumulation, which might reflect ADHE-mediated anticipation of anaerobic survival.
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Affiliation(s)
- Robert van Lis
- From the Aix Marseille Université, CNRS, BIP-UMR 7281, 13402 Marseille, France.,LBE, INRA, 11100 Narbonne, France
| | - Marion Popek
- From the Aix Marseille Université, CNRS, BIP-UMR 7281, 13402 Marseille, France
| | - Yohann Couté
- the Université Grenoble Alpes, BIG-BGE, 38000 Grenoble, France.,the Commissariat à l'Energie Atomique, BIG-BGE, 38000 Grenoble, France.,INSERM, BGE, 38000 Grenoble, France
| | - Artemis Kosta
- the Microscopy Core Facility, FR3479 Institut de Microbiologie de la Méditerranée, 13402 Marseille cedex 20, France, and
| | - Dominique Drapier
- the Institut de Biologie Physico-Chimique, UMR7141 CNRS-UPMC, 75005 Paris, France
| | - Wolfgang Nitschke
- From the Aix Marseille Université, CNRS, BIP-UMR 7281, 13402 Marseille, France
| | - Ariane Atteia
- From the Aix Marseille Université, CNRS, BIP-UMR 7281, 13402 Marseille, France,
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28
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Schmidt-Durán A, Alvarado-Ulloa C, Chacón-Cerdas R, Alvarado-Marchena LF, Flores-Mora D. Callogenesis and cell suspension establishment of tropical highland blackberry ( Rubus adenotrichos Schltdl.) and its microscopic analysis. SPRINGERPLUS 2016; 5:1717. [PMID: 27777853 PMCID: PMC5052243 DOI: 10.1186/s40064-016-3381-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 09/25/2016] [Indexed: 01/26/2023]
Abstract
Blackberries are fruits produced worldwide, with 25 % of their production centered in Mexico, Central and South America. Tropical highland blackberry is a fruit that can potentially enhance human health, due to their high content in phenolic compounds, which include anthocyanins, phenolic acids, tannins (gallotannins and elagitannins) and flavonoids. Therefore, the overall aim of this study is the development of a callus induction protocol, the establishment of blackberry cell suspensions (Rubus adenotrichos Schltdl.) and their cell analysis through optical microscopy and TEM, for the potential production of phenolic compounds. In order to produce callogenesis, segments of blackberry leaves were disinfected and placed in different concentrations of 2,4-D and the control media (0; 0.5; 1.0; 1.5; 2.0; 2.5 and 3.0 mg/l of 2,4-D); obtaining the higher size of calli in the medium with 1.5 mg/l of 2,4-D. After this determination, and for this specific treatment, a growth curve was performed through the use of fresh and dry weight parameters, in order to identify each of the growth stages. Furthermore, the calli obtained from the 1.5 mg/l of 2,4-D treatment were placed in two different culture media (MS and MS supplemented with 1.5 mg/l of 2,4-D) in order to establish the cell suspensions and the growth curve. To the best treatment, the total polyphenols were also quantified. It was determined that the MS medium is ideal for the growth and disintegration of the cell suspensions, obtaining 0.0256 mg of gallic acid/g of fresh sample. Finally, a cell callus and cell suspension analysis was performed through OM and TEM, evidencing a higher hystological differentiation in the calli, as well as the observation of antioxidant storage in the plastids.
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Affiliation(s)
- Alexander Schmidt-Durán
- Centro de Investigación en Biotecnología of the Escuela de Biología, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica
| | - Carlos Alvarado-Ulloa
- Centro de Investigación en Biotecnología of the Escuela de Biología, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica
| | - Randall Chacón-Cerdas
- Centro de Investigación en Biotecnología of the Escuela de Biología, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica
| | - Luis Fernando Alvarado-Marchena
- Centro de Investigación en Biotecnología of the Escuela de Biología, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica ; Laboratorio Institucional de Microscopía, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica
| | - Dora Flores-Mora
- Centro de Investigación en Biotecnología of the Escuela de Biología, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica
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29
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Jin Q, Paunesku T, Lai B, Gleber SC, Chen SI, Finney L, Vine D, Vogt S, Woloschak G, Jacobsen C. Preserving elemental content in adherent mammalian cells for analysis by synchrotron-based x-ray fluorescence microscopy. J Microsc 2016; 265:81-93. [PMID: 27580164 PMCID: PMC5217071 DOI: 10.1111/jmi.12466] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/11/2016] [Accepted: 08/02/2016] [Indexed: 01/20/2023]
Abstract
Trace metals play important roles in biological function, and x-ray fluorescence microscopy (XFM) provides a way to quantitatively image their distribution within cells. The faithfulness of these measurements is dependent on proper sample preparation. Using mouse embryonic fibroblast NIH/3T3 cells as an example, we compare various approaches to the preparation of adherent mammalian cells for XFM imaging under ambient temperature. Direct side-by-side comparison shows that plunge-freezing-based cryoimmobilization provides more faithful preservation than conventional chemical fixation for most biologically important elements including P, S, Cl, K, Fe, Cu, Zn and possibly Ca in adherent mammalian cells. Although cells rinsed with fresh media had a great deal of extracellular background signal for Cl and Ca, this approach maintained cells at the best possible physiological status before rapid freezing and it does not interfere with XFM analysis of other elements. If chemical fixation has to be chosen, the combination of 3% paraformaldehyde and 1.5 % glutaraldehyde preserves S, Fe, Cu and Zn better than either fixative alone. When chemically fixed cells were subjected to a variety of dehydration processes, air drying was proved to be more suitable than other drying methods such as graded ethanol dehydration and freeze drying. This first detailed comparison for x-ray fluorescence microscopy shows how detailed quantitative conclusions can be affected by the choice of cell preparation method.
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Affiliation(s)
- Qiaoling Jin
- Department of Physics & Astronomy, Weinberg College of Arts and Sciences, Evanston, Illinois, U.S.A
| | - Tatjana Paunesku
- Department of Radiation Oncology, Northwestern University, Chicago, Illinois, U.S.A
| | - Barry Lai
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, U.S.A
| | | | - S I Chen
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, U.S.A
| | - Lydia Finney
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, U.S.A
| | - David Vine
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, U.S.A
| | - Stefan Vogt
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, U.S.A
| | - Gayle Woloschak
- Department of Radiation Oncology, Northwestern University, Chicago, Illinois, U.S.A
| | - Chris Jacobsen
- Department of Physics & Astronomy, Weinberg College of Arts and Sciences, Evanston, Illinois, U.S.A.,Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, U.S.A
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30
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Kobayashi S, Iwamoto M, Haraguchi T. Live correlative light-electron microscopy to observe molecular dynamics in high resolution. Microscopy (Oxf) 2016; 65:296-308. [DOI: 10.1093/jmicro/dfw024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/01/2016] [Indexed: 12/19/2022] Open
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31
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Othman BA, Greenwood C, Abuelela AF, Bharath AA, Chen S, Theodorou I, Douglas T, Uchida M, Ryan M, Merzaban JS, Porter AE. Correlative Light-Electron Microscopy Shows RGD-Targeted ZnO Nanoparticles Dissolve in the Intracellular Environment of Triple Negative Breast Cancer Cells and Cause Apoptosis with Intratumor Heterogeneity. Adv Healthc Mater 2016; 5:1310-25. [PMID: 27111660 DOI: 10.1002/adhm.201501012] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 02/12/2016] [Indexed: 11/07/2022]
Abstract
ZnO nanoparticles (NPs) are reported to show a high degree of cancer cell selectivity with potential use in cancer imaging and therapy. Questions remain about the mode by which the ZnO NPs cause cell death, whether they exert an intra- or extracellular effect, and the resistance among different cancer cell types to ZnO NP exposure. The present study quantifies the variability between the cellular toxicity, dynamics of cellular uptake, and dissolution of bare and RGD (Arg-Gly-Asp)-targeted ZnO NPs by MDA-MB-231 cells. Compared to bare ZnO NPs, RGD-targeting of the ZnO NPs to integrin αvβ3 receptors expressed on MDA-MB-231 cells appears to increase the toxicity of the ZnO NPs to breast cancer cells at lower doses. Confocal microscopy of live MDA-MB-231 cells confirms uptake of both classes of ZnO NPs with a commensurate rise in intracellular Zn(2+) concentration prior to cell death. The response of the cells within the population to intracellular Zn(2+) is highly heterogeneous. In addition, the results emphasize the utility of dynamic and quantitative imaging in understanding cell uptake and processing of targeted therapeutic ZnO NPs at the cellular level by heterogeneous cancer cell populations, which can be crucial for the development of optimized treatment strategies.
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Affiliation(s)
- Basmah A. Othman
- Department of Materials; Imperial College London; Royal School of Mines; Exhibition Road London SW7 2AZ UK
| | - Christina Greenwood
- Cell and Molecular Biology Research Laboratory; Faculty of Medical Sciences; Post Graduate Medical Institute; Anglia Ruskin University; Bishop Hall Lane; Chelmsford CM1 1SQ UK
| | - Ayman F. Abuelela
- Cell Migration and Signaling Laboratory; Division of Biological and Environmental Sciences and Engineering; King Abdullah University of Science and Engineering (KAUST); Thuwal 23955-6900 Saudi Arabia
| | - Anil A. Bharath
- Department of Bioengineering; Imperial College London; Royal School of Mines; Exhibition Road London SW7 2AZ UK
| | - Shu Chen
- Department of Materials; Imperial College London; Royal School of Mines; Exhibition Road London SW7 2AZ UK
| | - Ioannis Theodorou
- Department of Materials; Imperial College London; Royal School of Mines; Exhibition Road London SW7 2AZ UK
| | - Trevor Douglas
- Department of Chemistry; Indiana University; 800 E. Kirkwood Avenue Bloomington IN 47405 USA
| | - Maskai Uchida
- Department of Chemistry; Indiana University; 800 E. Kirkwood Avenue Bloomington IN 47405 USA
| | - Mary Ryan
- Department of Materials; Imperial College London; Royal School of Mines; Exhibition Road London SW7 2AZ UK
| | - Jasmeen S. Merzaban
- Cell Migration and Signaling Laboratory; Division of Biological and Environmental Sciences and Engineering; King Abdullah University of Science and Engineering (KAUST); Thuwal 23955-6900 Saudi Arabia
| | - Alexandra E. Porter
- Department of Materials; Imperial College London; Royal School of Mines; Exhibition Road London SW7 2AZ UK
- Imperial College London and London Centre for Nanotechnology; London SW7 2AZ UK
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32
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Montanaro J, Gruber D, Leisch N. Improved ultrastructure of marine invertebrates using non-toxic buffers. PeerJ 2016; 4:e1860. [PMID: 27069800 PMCID: PMC4824901 DOI: 10.7717/peerj.1860] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 03/09/2016] [Indexed: 01/25/2023] Open
Abstract
Many marine biology studies depend on field work on ships or remote sampling locations where sophisticated sample preservation techniques (e.g., high-pressure freezing) are often limited or unavailable. Our aim was to optimize the ultrastructural preservation of marine invertebrates, especially when working in the field. To achieve chemically-fixed material of the highest quality, we compared the resulting ultrastructure of gill tissue of the mussel Mytilus edulis when fixed with differently buffered EM fixatives for marine specimens (seawater, cacodylate and phosphate buffer) and a new fixative formulation with the non-toxic PHEM buffer (PIPES, HEPES, EGTA and MgCl2). All buffers were adapted for immersion fixation to form an isotonic fixative in combination with 2.5% glutaraldehyde. We showed that PHEM buffer based fixatives resulted in equal or better ultrastructure preservation when directly compared to routine standard fixatives. These results were also reproducible when extending the PHEM buffered fixative to the fixation of additional different marine invertebrate species, which also displayed excellent ultrastructural detail. We highly recommend the usage of PHEM-buffered fixation for the fixation of marine invertebrates.
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Affiliation(s)
- Jacqueline Montanaro
- OCUVAC-Center of Ocular Inflammation and Infection, Laura Bassi Centers of Expertise, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna , Vienna , Austria
| | - Daniela Gruber
- Core Facility Cell Imaging and Ultrastructure Research, University of Vienna , Vienna , Austria
| | - Nikolaus Leisch
- Max Planck Institute for Marine Microbiology, Bremen, Germany; Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
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33
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Thai TQ, Nguyen HB, Saitoh S, Wu B, Saitoh Y, Shimo S, Elewa YHA, Ichii O, Kon Y, Takaki T, Joh K, Ohno N. Rapid specimen preparation to improve the throughput of electron microscopic volume imaging for three-dimensional analyses of subcellular ultrastructures with serial block-face scanning electron microscopy. Med Mol Morphol 2016; 49:154-62. [DOI: 10.1007/s00795-016-0134-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 01/31/2016] [Indexed: 11/24/2022]
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34
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Bert W, Slos D, Leroux O, Claeys M. Cryo-fixation and associated developments in transmission electron microscopy: a cool future for nematology. NEMATOLOGY 2016. [DOI: 10.1163/15685411-00002943] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
At present, the importance of sample preparation equipment for electron microscopy represents the driving force behind major breakthroughs in microscopy and cell biology. In this paper we present an introduction to the most commonly used cryo-fixation techniques, with special attention paid towards high-pressure freezing followed by freeze substitution. Techniques associated with cryo-fixation, such as immunolocalisation, cryo-sectioning, and correlative light and electron microscopy, are also highlighted. For studies that do not require high resolution, high quality results, or the immediate arrest of certain processes, conventional methods will provide answers to many questions. For some applications, such as immunocytochemistry, three-dimensional reconstruction of serial sections or electron tomography, improved preservation of the ultrastructure is required. This review of nematode cryo-fixation highlights that cryo-fixation not only results in a superior preservation of fine structural details, but also underlines the fact that some observations based on results solely obtained through conventional fixation approaches were either incorrect, or otherwise had severe limitations. Although the use of cryo-fixation has hitherto been largely restricted to model organisms, the advantages of cryo-fixation are sufficiently self-evident that we must conclude that the cryo-fixation method is highly likely to become the standard for nematode fixation in the near future.
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Affiliation(s)
- Wim Bert
- Nematology Research Unit, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Dieter Slos
- Nematology Research Unit, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Olivier Leroux
- Pteridology Research Group, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Myriam Claeys
- Nematology Research Unit, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
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35
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de Boer P, Hoogenboom JP, Giepmans BNG. Correlated light and electron microscopy: ultrastructure lights up! Nat Methods 2015; 12:503-13. [PMID: 26020503 DOI: 10.1038/nmeth.3400] [Citation(s) in RCA: 300] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 04/15/2015] [Indexed: 12/15/2022]
Abstract
Microscopy has gone hand in hand with the study of living systems since van Leeuwenhoek observed living microorganisms and cells in 1674 using his light microscope. A spectrum of dyes and probes now enable the localization of molecules of interest within living cells by fluorescence microscopy. With electron microscopy (EM), cellular ultrastructure has been revealed. Bridging these two modalities, correlated light microscopy and EM (CLEM) opens new avenues. Studies of protein dynamics with fluorescent proteins (FPs), which leave the investigator 'in the dark' concerning cellular context, can be followed by EM examination. Rare events can be preselected at the light microscopy level before EM analysis. Ongoing development-including of dedicated probes, integrated microscopes, large-scale and three-dimensional EM and super-resolution fluorescence microscopy-now paves the way for broad CLEM implementation in biology.
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Affiliation(s)
- Pascal de Boer
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Jacob P Hoogenboom
- Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - Ben N G Giepmans
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
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36
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Nicolle O, Burel A, Griffiths G, Michaux G, Kolotuev I. Adaptation of Cryo-Sectioning for IEM Labeling of Asymmetric Samples: A Study Using Caenorhabditis elegans. Traffic 2015; 16:893-905. [PMID: 25858477 DOI: 10.1111/tra.12289] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 04/07/2015] [Accepted: 04/08/2015] [Indexed: 01/17/2023]
Abstract
Cryo-sectioning procedures, initially developed by Tokuyasu, have been successfully improved for tissues and cultured cells, enabling efficient protein localization on the ultrastructural level. Without a standard procedure applicable to any sample, currently existing protocols must be individually modified for each model organism or asymmetric sample. Here, we describe our method that enables reproducible cryo-sectioning of Caenorhabditis elegans larvae/adults and embryos. We have established a chemical-fixation procedure in which flat embedding considerably simplifies manipulation and lateral orientation of larvae or adults. To bypass the limitations of chemical fixation, we have improved the hybrid cryo-immobilization-rehydration technique and reduced the overall time required to complete this procedure. Using our procedures, precise cryo-sectioning orientation can be combined with good ultrastructural preservation and efficient immuno-electron microscopy protein localization. Also, GFP fluorescence can be efficiently preserved, permitting a direct correlation of the fluorescent signal and its subcellular localization. Although developed for C. elegans samples, our method addresses the challenge of working with small asymmetric samples in general, and thus could be used to improve the efficiency of immuno-electron localization in other model organisms.
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Affiliation(s)
- Ophélie Nicolle
- Institut de Génétique et Développement de Rennes, Faculté de Médecine, CNRS, Université de Rennes 1, F-35043, Rennes, France
| | - Agnès Burel
- Plateforme microscopie électronique MRic, Université de Rennes 1, UEB, SFR Biosit, UMS 'BIOSIT' CNRS 3480-INSERM 018, F-35043, Rennes, France
| | - Gareth Griffiths
- Department of Biosciences, University of Oslo, Blindernveien 31, 0371 Oslo, Norway
| | - Grégoire Michaux
- Institut de Génétique et Développement de Rennes, Faculté de Médecine, CNRS, Université de Rennes 1, F-35043, Rennes, France.,Plateforme microscopie électronique MRic, Université de Rennes 1, UEB, SFR Biosit, UMS 'BIOSIT' CNRS 3480-INSERM 018, F-35043, Rennes, France
| | - Irina Kolotuev
- Institut de Génétique et Développement de Rennes, Faculté de Médecine, CNRS, Université de Rennes 1, F-35043, Rennes, France.,Plateforme microscopie électronique MRic, Université de Rennes 1, UEB, SFR Biosit, UMS 'BIOSIT' CNRS 3480-INSERM 018, F-35043, Rennes, France
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37
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Bobik K, Dunlap JR, Burch-Smith TM. Tandem high-pressure freezing and quick freeze substitution of plant tissues for transmission electron microscopy. J Vis Exp 2014:e51844. [PMID: 25350384 PMCID: PMC4692431 DOI: 10.3791/51844] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Since the 1940s transmission electron microscopy (TEM) has been providing biologists with ultra-high resolution images of biological materials. Yet, because of laborious and time-consuming protocols that also demand experience in preparation of artifact-free samples, TEM is not considered a user-friendly technique. Traditional sample preparation for TEM used chemical fixatives to preserve cellular structures. High-pressure freezing is the cryofixation of biological samples under high pressures to produce very fast cooling rates, thereby restricting ice formation, which is detrimental to the integrity of cellular ultrastructure. High-pressure freezing and freeze substitution are currently the methods of choice for producing the highest quality morphology in resin sections for TEM. These methods minimize the artifacts normally associated with conventional processing for TEM of thin sections. After cryofixation the frozen water in the sample is replaced with liquid organic solvent at low temperatures, a process called freeze substitution. Freeze substitution is typically carried out over several days in dedicated, costly equipment. A recent innovation allows the process to be completed in three hours, instead of the usual two days. This is typically followed by several more days of sample preparation that includes infiltration and embedding in epoxy resins before sectioning. Here we present a protocol combining high-pressure freezing and quick freeze substitution that enables plant sample fixation to be accomplished within hours. The protocol can readily be adapted for working with other tissues or organisms. Plant tissues are of special concern because of the presence of aerated spaces and water-filled vacuoles that impede ice-free freezing of water. In addition, the process of chemical fixation is especially long in plants due to cell walls impeding the penetration of the chemicals to deep within the tissues. Plant tissues are therefore particularly challenging, but this protocol is reliable and produces samples of the highest quality.
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Affiliation(s)
- Krzysztof Bobik
- Department of Biochemical, Cellular and Molecular Biology, University of Tennessee, Knoxville
| | - John R Dunlap
- Advanced Microscopy and Imaging Facility, University of Tennessee, Knoxville
| | - Tessa M Burch-Smith
- Department of Biochemical, Cellular and Molecular Biology, University of Tennessee, Knoxville;
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38
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Sarkar P, Bosneaga E, Yap EG, Das J, Tsai WT, Cabal A, Neuhaus E, Maji D, Kumar S, Joo M, Yakovlev S, Csencsits R, Yu Z, Bajaj C, Downing KH, Auer M. Electron tomography of cryo-immobilized plant tissue: a novel approach to studying 3D macromolecular architecture of mature plant cell walls in situ. PLoS One 2014; 9:e106928. [PMID: 25207917 PMCID: PMC4160213 DOI: 10.1371/journal.pone.0106928] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 08/01/2014] [Indexed: 11/18/2022] Open
Abstract
Cost-effective production of lignocellulosic biofuel requires efficient breakdown of cell walls present in plant biomass to retrieve the wall polysaccharides for fermentation. In-depth knowledge of plant cell wall composition is therefore essential for improving the fuel production process. The precise spatial three-dimensional (3D) organization of cellulose, hemicellulose, pectin and lignin within plant cell walls remains unclear to date since the microscopy techniques used so far have been limited to two-dimensional, topographic or low-resolution imaging, or required isolation or chemical extraction of the cell walls. In this paper we demonstrate that by cryo-immobilizing fresh tissue, then either cryo-sectioning or freeze-substituting and resin embedding, followed by cryo- or room temperature (RT) electron tomography, respectively, we can visualize previously unseen details of plant cell wall architecture in 3D, at macromolecular resolution (∼2 nm), and in near-native state. Qualitative and quantitative analyses showed that wall organization of cryo-immobilized samples were preserved remarkably better than conventionally prepared samples that suffer substantial extraction. Lignin-less primary cell walls were well preserved in both self-pressurized rapidly frozen (SPRF), cryo-sectioned samples as well as high-pressure frozen, freeze-substituted and resin embedded (HPF-FS-resin) samples. Lignin-rich secondary cell walls appeared featureless in HPF-FS-resin sections presumably due to poor stain penetration, but their macromolecular features could be visualized in unprecedented details in our cryo-sections. While cryo-tomography of vitreous tissue sections is currently proving to be instrumental in developing 3D models of lignin-rich secondary cell walls, here we confirm that the technically easier method of RT-tomography of HPF-FS-resin sections could be used immediately for routine study of low-lignin cell walls. As a proof of principle, we characterized the primary cell walls of a mutant (cob-6) and wild type Arabidopsis hypocotyl parenchyma cells by RT-tomography of HPF-FS-resin sections, and detected a small but significant difference in spatial organization of cellulose microfibrils in the mutant walls.
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Affiliation(s)
- Purbasha Sarkar
- Energy Biosciences Institute, University of California, Berkeley, California, United States of America
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Elena Bosneaga
- Energy Biosciences Institute, University of California, Berkeley, California, United States of America
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Edgar G. Yap
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Jyotirmoy Das
- Energy Biosciences Institute, University of California, Berkeley, California, United States of America
| | - Wen-Ting Tsai
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Angelo Cabal
- Energy Biosciences Institute, University of California, Berkeley, California, United States of America
| | - Erica Neuhaus
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Dolonchampa Maji
- Energy Biosciences Institute, University of California, Berkeley, California, United States of America
| | - Shailabh Kumar
- Energy Biosciences Institute, University of California, Berkeley, California, United States of America
| | - Michael Joo
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Sergey Yakovlev
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Roseann Csencsits
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Zeyun Yu
- Department of Computer Science, University of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Chandrajit Bajaj
- Department of Computer Sciences & The Institute of Computational Engineering and Sciences, University of Texas, Austin, Texas, United States of America
| | - Kenneth H. Downing
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Manfred Auer
- Energy Biosciences Institute, University of California, Berkeley, California, United States of America
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- * E-mail:
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39
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Cain NE, Tapley EC, McDonald KL, Cain BM, Starr DA. The SUN protein UNC-84 is required only in force-bearing cells to maintain nuclear envelope architecture. ACTA ACUST UNITED AC 2014; 206:163-72. [PMID: 25023515 PMCID: PMC4107780 DOI: 10.1083/jcb.201405081] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
SUN-KASH bridges that connect the nucleoskeleton to the cytoskeleton are only required to maintain nuclear envelope spacing in cells subjected to increased mechanical forces, such as muscle cells. The nuclear envelope (NE) consists of two evenly spaced bilayers, the inner and outer nuclear membranes. The Sad1p and UNC-84 (SUN) proteins and Klarsicht, ANC-1, and Syne homology (KASH) proteins that interact to form LINC (linker of nucleoskeleton and cytoskeleton) complexes connecting the nucleoskeleton to the cytoskeleton have been implicated in maintaining NE spacing. Surprisingly, the NE morphology of most Caenorhabditis elegans nuclei was normal in the absence of functional SUN proteins. Distortions of the perinuclear space observed in unc-84 mutant muscle nuclei resembled those previously observed in HeLa cells, suggesting that SUN proteins are required to maintain NE architecture in cells under high mechanical strain. The UNC-84 protein with large deletions in its luminal domain was able to form functional NE bridges but had no observable effect on NE architecture. Therefore, SUN-KASH bridges are only required to maintain NE spacing in cells subjected to increased mechanical forces. Furthermore, SUN proteins do not dictate the width of the NE.
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Affiliation(s)
- Natalie E Cain
- Department of Molecular and Cellular Biology and Department of Physics, University of California, Davis, Davis, CA 95616
| | - Erin C Tapley
- Department of Molecular and Cellular Biology and Department of Physics, University of California, Davis, Davis, CA 95616
| | - Kent L McDonald
- Electron Microscope Laboratory, University of California, Berkeley, Berkeley, CA 94720
| | - Benjamin M Cain
- Department of Molecular and Cellular Biology and Department of Physics, University of California, Davis, Davis, CA 95616
| | - Daniel A Starr
- Department of Molecular and Cellular Biology and Department of Physics, University of California, Davis, Davis, CA 95616
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40
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Burkhardt P, Grønborg M, McDonald K, Sulur T, Wang Q, King N. Evolutionary insights into premetazoan functions of the neuronal protein homer. Mol Biol Evol 2014; 31:2342-55. [PMID: 24899667 PMCID: PMC4137706 DOI: 10.1093/molbev/msu178] [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] [Indexed: 12/11/2022] Open
Abstract
Reconstructing the evolution and ancestral functions of synaptic proteins promises to shed light on how neurons first evolved. The postsynaptic density (PSD) protein Homer scaffolds membrane receptors and regulates Ca2+ signaling in diverse metazoan cell types (including neurons and muscle cells), yet its ancestry and core functions are poorly understood. We find that the protein domain organization and essential biochemical properties of metazoan Homer proteins, including their ability to tetramerize, are conserved in the choanoflagellate Salpingoeca rosetta, one of the closest living relatives of metazoans. Unlike in neurons, Homer localizes to the nucleoplasm in S. rosetta and interacts directly with Flotillin, a protein more commonly associated with cell membranes. Surprisingly, we found that the Homer/Flotillin interaction and its localization to the nucleus are conserved in metazoan astrocytes. These findings suggest that Homer originally interacted with Flotillin in the nucleus of the last common ancestor of metazoans and choanoflagellates and was later co-opted to function as a membrane receptor scaffold in the PSD.
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Affiliation(s)
- Pawel Burkhardt
- Howard Hughes Medical Institute and the Department of Molecular and Cell Biology, University of California, Berkeley
| | | | - Kent McDonald
- Electron Microscopy Laboratory, University of California, Berkeley
| | - Tara Sulur
- Howard Hughes Medical Institute and the Department of Molecular and Cell Biology, University of California, Berkeley
| | - Qi Wang
- California Institute for Quantitative Biosciences, University of California, Berkeley
| | - Nicole King
- Howard Hughes Medical Institute and the Department of Molecular and Cell Biology, University of California, Berkeley
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41
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McDonald KL. Out with the old and in with the new: rapid specimen preparation procedures for electron microscopy of sectioned biological material. PROTOPLASMA 2014; 251:429-448. [PMID: 24258967 DOI: 10.1007/s00709-013-0575-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 10/22/2013] [Indexed: 06/02/2023]
Abstract
This article presents the best current practices for preparation of biological samples for examination as thin sections in an electron microscope. The historical development of fixation, dehydration, and embedding procedures for biological materials are reviewed for both conventional and low temperature methods. Conventional procedures for processing cells and tissues are usually done over days and often produce distortions, extractions, and other artifacts that are not acceptable for today's structural biology standards. High-pressure freezing and freeze substitution can minimize some of these artifacts. New methods that reduce the times for freeze substitution and resin embedding to a few hours are discussed as well as a new rapid room temperature method for preparing cells for on-section immunolabeling without the use of aldehyde fixatives.
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Affiliation(s)
- Kent L McDonald
- Electron Microscope Laboratory, University of California, 26 Giannini Hall, Berkeley, CA, 94720, USA,
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