1
|
Nomura M, Ohta K, Nishigami Y, Nakayama T, Nakamura KI, Tadakuma K, Galipon J. Three-dimensional architecture and assembly mechanism of the egg-shaped shell in testate amoeba Paulinella micropora. Front Cell Dev Biol 2023; 11:1232685. [PMID: 37731817 PMCID: PMC10507277 DOI: 10.3389/fcell.2023.1232685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 08/21/2023] [Indexed: 09/22/2023] Open
Abstract
Unicellular euglyphid testate amoeba Paulinella micropora with filose pseudopodia secrete approximately 50 siliceous scales into the extracellular template-free space to construct a shell isomorphic to that of its mother cell. This shell-constructing behavior is analogous to building a house with bricks, and a complex mechanism is expected to be involved for a single-celled amoeba to achieve such a phenomenon; however, the three-dimensional (3D) structure of the shell and its assembly in P. micropora are still unknown. In this study, we aimed to clarify the positional relationship between the cytoplasmic and extracellular scales and the structure of the egg-shaped shell in P. micropora during shell construction using focused ion beam scanning electron microscopy (FIB-SEM). 3D reconstruction revealed an extensive invasion of the electron-dense cytoplasm between the long sides of the positioned and stacked scales, which was predicted to be mediated by actin filament extension. To investigate the architecture of the shell of P. micropora, each scale was individually segmented, and the position of its centroid was plotted. The scales were arranged in a left-handed, single-circular ellipse in a twisted arrangement. In addition, we 3D printed individual scales and assembled them, revealing new features of the shell assembly mechanism of P. micropora. Our results indicate that the shell of P. micropora forms an egg shape by the regular stacking of precisely designed scales, and that the cytoskeleton is involved in the construction process.
Collapse
Affiliation(s)
- Mami Nomura
- Faculty of Science, Yamagata University, Yamagata, Japan
| | - Keisuke Ohta
- Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Japan
- Advanced Imaging Research Center, Kurume University School of Medicine, Kurume, Japan
| | - Yukinori Nishigami
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
- Research Institute for Electronic Science, Hokkaido University, Sapporo, Japan
| | - Takuro Nakayama
- Center for Computational Sciences, University of Tsukuba, Tsukuba, Japan
| | - Kei-Ichiro Nakamura
- Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Japan
- Advanced Imaging Research Center, Kurume University School of Medicine, Kurume, Japan
| | - Kenjiro Tadakuma
- Graduate School of Information Sciences, Tohoku University, Sendai, Japan
- Tough Cyberphysical AI Research Center, Tohoku University, Sendai, Japan
| | - Josephine Galipon
- Graduate School of Information Sciences, Tohoku University, Sendai, Japan
- Institute for Advanced Sciences, Keio University, Tsuruoka, Japan
- Graduate School of Media and Governance, Keio University, Fujisawa, Japan
- Graduate School of Science and Engineering, Yamagata University, Yonezawa, Japan
| |
Collapse
|
2
|
Lei C, Wang YH, Zhuang PX, Li YT, Wan QQ, Ma YX, Tay FR, Niu LN. Applications of Cryogenic Electron Microscopy in Biomineralization Research. J Dent Res 2021; 101:505-514. [PMID: 34918556 DOI: 10.1177/00220345211053814] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Biological mineralization is a natural process manifested by living organisms in which inorganic minerals crystallize under the scrupulous control of biomolecules, producing hierarchical organic-inorganic composite structures with physical properties and design that galvanize even the most ardent structural engineer and architect. Understanding the mechanisms that control the formation of biominerals is challenging in the biomimetic engineering of hard tissues. In this regard, the contribution of cryogenic electron microscopy (cryo-EM) has been nothing short of phenomenal. By preserving materials in their native hydrated status and reducing damage caused by ion beam radiation, cryo-EM outperforms conventional transmission electron microscopy in its ability to directly observe the morphologic evolution of mineral precursor phases at different stages of biomineralization with nanoscale spatial resolution and subsecond temporal resolution in 2 or 3 dimensions. In the present review, the development and applications of cryo-EM are discussed to support the use of this powerful technique in dental research. Because of the rapid development of cryogenic sample preparation techniques, direct electron detection, and image-processing algorithms, the last decade has witnessed an exponential increase in the use of cryo-EM in structural biology and materials research. By amalgamating with other analytic techniques, cryo-EM may be used for qualitative and quantitative analyses of the kinetics and thermodynamic mechanisms in which organic macromolecules participate in the transformation of mineral precursors from their original liquid state to amorphous and ultimately crystalline phases. The present review concentrates on the biomineralization of calcium phosphate mineral phases, while that of calcium carbonate, silica, and magnetite is only briefly mentioned. Bioinspired organic matrix-mediated inorganic crystallization strategies are discussed from the perspective of tissue regeneration engineering.
Collapse
Affiliation(s)
- C Lei
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Key Laboratory of Stomatology, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Y H Wang
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Key Laboratory of Stomatology, School of Stomatology, the Fourth Military Medical University, Xi'an, China.,Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, China
| | - P X Zhuang
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Key Laboratory of Stomatology, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Y T Li
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Key Laboratory of Stomatology, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Q Q Wan
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Key Laboratory of Stomatology, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Y X Ma
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Key Laboratory of Stomatology, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - F R Tay
- The Graduate School, Augusta University, Augusta, GA, USA
| | - L N Niu
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Key Laboratory of Stomatology, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| |
Collapse
|
3
|
Ravi RT, Leung MR, Zeev-Ben-Mordehai T. Looking back and looking forward: contributions of electron microscopy to the structural cell biology of gametes and fertilization. Open Biol 2020; 10:200186. [PMID: 32931719 PMCID: PMC7536082 DOI: 10.1098/rsob.200186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/25/2020] [Indexed: 01/22/2023] Open
Abstract
Mammalian gametes-the sperm and the egg-represent opposite extremes of cellular organization and scale. Studying the ultrastructure of gametes is crucial to understanding their interactions, and how to manipulate them in order to either encourage or prevent their union. Here, we survey the prominent electron microscopy (EM) techniques, with an emphasis on considerations for applying them to study mammalian gametes. We review how conventional EM has provided significant insight into gamete ultrastructure, but also how the harsh sample preparation methods required preclude understanding at a truly molecular level. We present recent advancements in cryo-electron tomography that provide an opportunity to image cells in a near-native state and at unprecedented levels of detail. New and emerging cellular EM techniques are poised to rekindle exploration of fundamental questions in mammalian reproduction, especially phenomena that involve complex membrane remodelling and protein reorganization. These methods will also allow novel lines of enquiry into problems of practical significance, such as investigating unexplained causes of human infertility and improving assisted reproductive technologies for biodiversity conservation.
Collapse
Affiliation(s)
- Ravi Teja Ravi
- Cryo-Electron Microscopy, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584CH Utrecht, The Netherlands
| | - Miguel Ricardo Leung
- Cryo-Electron Microscopy, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584CH Utrecht, The Netherlands
- Division of Structural Biology, Wellcome Centre for Human Genetics, The University of Oxford, Oxford OX3 7BN, UK
| | - Tzviya Zeev-Ben-Mordehai
- Cryo-Electron Microscopy, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584CH Utrecht, The Netherlands
- Division of Structural Biology, Wellcome Centre for Human Genetics, The University of Oxford, Oxford OX3 7BN, UK
| |
Collapse
|