Surface Ornamentation of &lt;i&gt;Cyanophora paradoxa&lt;/i&gt; (Cyanophorales, Glaucophyta) Cells as Revealed by Ultra-High Resolution Field Emission Scanning Electron Microscopy

Takahashi, Toshiyuki; Sato, Mayuko; Toyooka, Kiminori; Nozaki, Hisayoshi

doi:10.1508/cytologia.79.119

Cited by 11 publications

(23 citation statements)

References 16 publications

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“…, Kugrens , Takahashi et al. ), the cell coverings of Cyanophora species consist of the cell membrane and underlying flattened vesicles (plate vesicles) each of which includes a plate. The surfaces of plates and vesicles are observable under TEM as replicas, using the freeze‐fracture method by which the cell coverings are scratched at random depths to peel the cell membrane, vesicles, and plates, so that vesicles and plates are exposed (Kugrens et al.…”

Section: Resultsmentioning

confidence: 99%

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Five Cyanophora (Cyanophorales, Glaucophyta) species delineated based on morphological and molecular data

Takahashi

Sato

Toyooka

et al. 2014

Journal of Phycology

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Cyanophora is an important glaucophyte genus of unicellular biflagellates that may have retained ancestral features of photosynthetic eukaryotes. The nuclear genome of Cyanophora was recently sequenced, but taxonomic studies of more than two strains are lacking for this genus. Furthermore, no study has used molecular methods to taxonomically delineate Cyanophora species. Here, we delimited the species of Cyanophora using light and electron microscopy, combined with molecular data from several globally distributed strains, including one newly established. Using a light microscope, we identified two distinct morphological groups: one with ovoid to ellipsoidal vegetative cells and another with dorsoventrally flattened or broad, bean-shaped vegetative cells containing duplicated plastids. Our light and scanning electron microscopy clearly distinguished three species with ovoid to ellipsoidal cells (C. paradoxa Korshikov, C. cuspidata Tos.Takah. & Nozaki sp. nov., and C. kugrensii Tos.Takah. & Nozaki sp. nov.) and two species with broad, bean-shaped cells (C. biloba Kugrens, B.L.Clay, C.J.Mey. & R.E.Lee and C. sudae Tos.Takah. & Nozaki sp. nov.) based on differences in cell shape and surface ornamentations of the vegetative cells under the field-emission scanning electron microscope. Molecular phylogenetic analyses of P700 chl a apoprotein A2 (psaB) genes and internal transcribed spacer (ITS) regions of nuclear ribosomal DNA (rDNA), as well as a comparison of secondary structures of nuclear rDNA ITS-2 and genetic distances of psaB genes, supported the delineation of five morphological species of Cyanophora.

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Section: Resultsmentioning

confidence: 99%

“…Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and ultra‐high resolution field‐emission (FE) SEM were performed following Takahashi et al. () and Matsuzaki et al. () and freeze‐fracture electron microscopy was performed following Okuda et al.…”

Section: Methodsmentioning

confidence: 99%

Five Cyanophora (Cyanophorales, Glaucophyta) species delineated based on morphological and molecular data

Takahashi

Sato

Toyooka

et al. 2014

Journal of Phycology

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“…Cyanophora Chong et al 2014) 遊泳性 Cyanophora と不動厚膜球状性 Glaucocystis の両属で，基本的には同じ「細胞膜の内側で小葉状の扁平小胞が密に裏打ちする」細胞外被立体微細構造をもつことを明らかにしてきた (Takahashi et al 2014a(Takahashi et al , 2014b(Takahashi et al , 2015 …”

Section: Cyanophoraunclassified

“…このように灰色植物は，一次植物の起源を研究する上で重要であると考えられる．しかし，複雑な多細胞体が進化している紅色植物と緑色植物に関しては，Linnaeus (1753) 以前から既に多くの研究者によって様々な手法で種レベルの分類が行われてきた (e.g., 李 1596) のに対して，灰色植物の種レベルの分類は今日まで大きく立ち遅れていた．灰色植物の種分類学的研究では野外試料を直接用いた光学顕微鏡観察・記載が中心で，クローン株レベルの形態学的多様性については殆ど研究されておらず，分子情報も用いられていなかった (Takahashi et al 2014a)．灰色植物の微細構造の研究はいくつかあったが，微細構造上の差異については殆ど報告されていなかった．そこで我々は灰色植物の客観的かつ全世界レベルの種レベルの分類体系を構築することを目的とし，再現性のある材料として世界の株保存機関の保存培養株を入手し，独自に確立した新規株を加えて，分子系統解析と比較形態観察を実施した (Takahashi et al 2014a)．形態比較では光学顕微鏡観察と従来の電子顕微鏡による観察に加え，近年生物学に応用され始めた新しい電子顕微鏡法による比較観察を実施した (Takahashi et al 2014a(Takahashi et al , 2014b(Takahashi et al , 2015．最新の電子顕微鏡機器を用いることで，微細な灰色植物であっても巨視的な植物と同様に形態学的に種が分類できると期待したからである．特に原形質体表層の外被構造に着目した形態比較の結果，種を識別する微細構造上の形態的多様性が灰色植物 2 属 (図 1) で明らかとなった．…”

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Toward the establishment of glaucophyte taxonomic system based on the threedimensional recognition of ultrastructures

Takahashi

Nozaki

2016

PL. MORPH.

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11 東京大学大学院理学系研究科生物科学専攻〒113-0033 東京都文京区本郷 7-3-1 Summary: Glaucophytes are one of the three major lineages of primary photosynthetic eukaryotes (Archaeplastida), together with red algae and Chloroplastida (green algae and embryophytes). Within Archaeplastida, glaucophytes are thought to retain ancestral features of the first photosynthetic eukaryote. The biflagellate glaucophyte genus Cyanophora has been widely studied as a model organism of primitive phototrophs, with released nuclear genome sequence, but no morphological study has clearly shown ultrastructural diversity to delimit glaucophyte species. Recently, we applied advanced electron microscopic (EM) methodologies for comparative morphology in a purpose of delineating the glaucophyte species. On the basis of ultra-high resolution field emission scanning EM (FE-SEM), we demonstrated that the cell surface of Cyanophora was ornamented with angular fenestrations framed by ridges. As supported by observation using several transmission EM methods, these ridges were formed by the edges of overlapping or attaching outermost plate vesicles that distributed throughout the cell periphery just underneath the cell membrane. Based on differences in the pattern of surface ornamentations detected by FE-SEM, Cyanophora biloba and C. sudae were distinguished from each other. FE-SEM, however, cannot be applied for the native protoplast surfaces that are enclosed by a thick cell wall or extracellular matrix as in the immotile glaucophyte genus Glaucocystis. Alternatively, we very recently used the advanced ultra-high voltage EM tomography to unveil the in situ peripheral ultrastructure of protoplasts in Glaucocystis and revealed the ultrastructural diversity in this genus. Furthermore, Glaucocystis cells have numerous, leaflet-like flattened vesicles distributed throughout the protoplast periphery just underneath the cell membrane, as in Cyanophora as well as some secondary photosynthetic eukaryotes. Thus, a similar 3D peripheral ultrastructure might have appeared in the common ancestor of glaucophytes and/or the first photosynthetic eukaryote.

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“…cells were dehydrated through an ethanol series, replaced by propylene oxide, and embedded in Spurr s resin (Spurr 1969). Sections were cut using a diamond knife on an Ultracut UCT (Leica, Vienna, Austria), stained with uranyl acetate and lead citrate, and observed with a JEM-1010 electron microscope (JEOL, Tokyo, Japan), as described previously (Takahashi et al 2014).…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

Taxonomic Study of <i>Pyrobotrys</i> (Spondylomoraceae, Chlorophyceae) Based on Comparative Morphological and Molecular Analyses of Culture Strains Established Using Novel Methods

et al. 2015

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Summary Taxonomic studies of the spondylomoracean genus Pyrobotrys have remained at traditional levels due to the lack of molecular phylogenetic analyses and available culture strains for reexaminations. Here, we established new culture strains of Pyrobotrys using novel culturing methods, and classified them into three species, namely, P. casinoensis, P. elongata, and P. squarrosa, based on comparative microscopic observations and molecular phylogeny. Although P. elongata is characterized by its enormous stigma in cells of the most posterior tier in a colony, such a species has not been reported since its original description in 1938. In the present study, the presence of an enormous stigma was confirmed based on light microscopy in three P. elongata strains originating from two localities. Based on transmission electron microscopy, the large stigma of P. elongata was essentially identical to the stigma of other species of Pyrobotrys in having a single layer of stigma globules. Our molecular phylogeny demonstrated that P. elongata was robustly separated from other species of Pyrobotrys.

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Surface Ornamentation of <i>Cyanophora paradoxa</i> (Cyanophorales, Glaucophyta) Cells as Revealed by Ultra-High Resolution Field Emission Scanning Electron Microscopy

Cited by 11 publications

References 16 publications

Five Cyanophora (Cyanophorales, Glaucophyta) species delineated based on morphological and molecular data

Five Cyanophora (Cyanophorales, Glaucophyta) species delineated based on morphological and molecular data

Toward the establishment of glaucophyte taxonomic system based on the threedimensional recognition of ultrastructures

Taxonomic Study of <i>Pyrobotrys</i> (Spondylomoraceae, Chlorophyceae) Based on Comparative Morphological and Molecular Analyses of Culture Strains Established Using Novel Methods

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