Researcher Database

Takeo Horiguchi
Faculty of Science Biological Sciences Biodiversity
Professor

Researcher Profile and Settings

Affiliation

  • Faculty of Science Biological Sciences Biodiversity

Job Title

  • Professor

Degree

  • (BLANK)

J-Global ID

Research Interests

  • 植物系統分類学   Plant Systematics   

Research Areas

  • Life sciences / Biodiversity and systematics

Association Memberships

  • Phycological Society of Southern Africa   British Phycological Society   Phycological Society of America   International Phycological Society   SOCIETY OF EVOLUTIONARY STUDIES, JAPAN   JAPANESE SOCIETY FOR PLANT SYSTEMATICS   アメリカ藻類学会(PHYCOLOGICAL SOCIETY OF AMERICA)   国際藻類学会(INTERNATIONAL PHYCOLOGICAL SOCIETY)   THE JAPANESE SOCIETY OF PHYCOLOGY   日本植物学会   

Research Activities

Published Papers

  • Yamada N, Bolton JJ, Trobajo R, Mann DG, Dąbek P, Witkowski A, Onuma R, Horiguchi T, Kroth PG
    Scientific reports 9 (1) 10474  2019/07 [Refereed][Not invited]
  • Chrysochromulina andersonii sp. nov. (Prymnesiophyceae), a new flagellate haptophyte synbiotic with radiolarians.
    YUASA Tomoko, KAWACHI Masanobu, HORIGUCHI Takeo, TAKAHASHI Osamu
    Pfycologia 58 (2) 211 - 224 2019 [Refereed][Not invited]
  • Dawut Mahmutjan, Sym Stuart D, Horiguchi Takeo
    PHYCOLOGICAL RESEARCH 66 (4) 300 - 309 1322-0829 2018/10 [Refereed][Not invited]
  • Plagiodinium ballux sp. nov. (Dinophyceae), a deep (36 m) sand dwelling dinoflagellate from subtropical Japan.
    YAMADA Norico, DAWUT Mahmutjan, TERADA Ryuta, HORIGUCHI Takeo
    Phycological Research https://doi.org/10.1111/pre.12 2018/08 [Refereed][Not invited]
  • Ultrastructure and phylogeny of a new species of mixotrophic dinoflagellate, Paragymnodinium stigmaticum sp. nov. (Gymnodiniales, Dinophyceae)
    YOKOUCHI Koh, ONUMA Ryo, HORIGUCHI Takeo
    PHYCOLOGIA 57 (5) 539 - 554 2018/07 [Refereed][Not invited]
  • Kevin C. Wakeman, Aika Yamaguchi, Takeo Horiguchi
    Protist 169 (3) 333 - 350 1618-0941 2018/07/01 [Refereed][Not invited]
     
    This study describes a novel species of Haplozoon, H. ezoense n. sp., a dinoflagellate parasite isolated from the intestines of Praxillella pacifica (Polychaeta). Trophonts (feeding stages) of H. ezoense n. sp. were isolated and studied with scanning and transmission electron microscopy, and molecular phylogenetic analyses was performed using 18S rDNA and 28S rDNA. Trophonts had an average length of 120 μm, and were linear, forming a single longitudinal row comprising a trophocyte with a stylet, an average of 14 gonocytes (width = 10 μm), and bulbous cells that we concluded were likely sporocytes. The surface of H. ezoense n. sp. was covered with projections of the amphiesma. Sections viewed under TEM revealed multiple triple membrane-bound organelles reminiscent of relic non-photosynthetic plastids within the gonocytes. Haplozoon ezoense n. sp., H. praxillellae, and H. axiothellae formed a well-supported clade in the 18S rDNA datasets. The sequences of H. ezoense n. sp. differed from H. praxillellae, a species of Haplozoon isolated from the same host species in the Northeast Pacific, at 88/1,748 bases and 155/1,752 bases from H. axiothellae. Concatenated 18S rDNA and 28S rDNA datasets were unable to resolve the deeper relationships of Haplozoon in the context of dinoflagellates.
  • Kevin C. Wakeman, Akinori Yabuki, Katsunori Fujikura, Ko Tomikawa, Takeo Horiguchi
    Journal of Eukaryotic Microbiology 65 (3) 372 - 381 1550-7408 2018/05/01 [Refereed][Not invited]
     
    In an effort to broaden our understanding of the biodiversity and distribution of gregarines infecting crustaceans, this study describes two new species of gregarines, Thiriotia hyperdolphinae n. sp. and Cephaloidophora oradareae n. sp., parasitizing a deep sea amphipod (Oradarea sp.). Amphipods were collected using the ROV Hyper-Dolphin at a depth of 855 m while on a cruise in Sagami Bay, Japan. Gregarine trophozoites and gamonts were isolated from the gut of the amphipod and studied with light and scanning electron microscopy, and phylogenetic analysis of 18S rDNA. Thiriotia hyperdolphinae n. sp. was distinguished from existing species based on morphology, phylogenetic position, as well as host niche and geographic locality. Cephaloidophora oradareae n. sp. distinguished itself from existing Cephaloidophora, based on a difference in host (Oradarea sp.), geographic location, and to a certain extent morphology. We established this latter new species with the understanding that a more comprehensive examination of diversity at the molecular level is necessary within Cephaloidophora. Results from the 18S rDNA molecular phylogeny showed that T. hyperdolphinae n. sp. was positioned within a clade consisting of Thiriotia spp., while C. oradareae n. sp. grouped within the Cephaloidophoridae. Still, supplemental genetic information from gregarines infecting crustaceans will be needed to better understand relationships within this group of apicomplexans.
  • Mahmutjan Dawut, Stuart D. Sym, Shoichiro Suda, Takeo Horiguchi
    Phycologia 57 (2) 169 - 178 2330-2968 2018/01/11 [Refereed][Not invited]
     
    A new species of the dinoflagellate genus Bysmatrum was isolated from tidal pool samples originating from Cape Peninsula, South Africa. This new species was investigated by light, scanning and transmission electron microscopy, and its phylogenetic affinities were analyzed using molecular data. Cells were pentagonal in ventral view, 25–45 lm long and 20–42.5 lm wide and only slightly flattened in a dorsiventral plane. The epitheca, in apical view, was almost circular, with a slight ventral depression. Plate tabulation (PO, X, 40, 3a, 700, 6c, 4s, 5000, 20000) was typical for the genus Bysmatrum. Apical plate 10 was heptagonal and broadly asymmetric, with an elongated, fingerlike extension at the base. The intercalary plates 2a and 3a were separated by a direct connection between plates 30 and 400. The thecal plates were perforated by pores of different sizes and ornamented with linearly arranged reticulations. Intercalary bands were smooth, and antapical plates were not indented. This new species differs from the five other known species of the genus Bysmatrum in morphology (e.g. the shape of apical plate 10) and it occupies an isolated position in phylogenetic trees inferred by analyses of small-subunit ribosomal DNA (SSU-rDNA) sequence data. This also represents the first report of the SSU rDNA sequence for Bysmatrum arenicola.
  • Yamaguchi Aika, Wakeman Kevin C, Hoppenrath Mona, Horiguchi Takeo, Kawai Hiroshi
    PHYCOLOGIA 57 (6) 630 - 640 0031-8884 2018 [Refereed][Not invited]
  • Takeo Horiguchi, Rui Moriya, Sohail K. Pinto, Ryuta Terada
    PHYCOLOGICAL RESEARCH 65 (4) 272 - 279 1322-0829 2017/10 [Refereed][Not invited]
     
    A new species of benthic marine dinoflagellate, Pyramidodinium spinulosumHoriguchi, Moriya, Pinto & Terada is described from the deep (36m) seafloor off Mageshima Island, Kagoshima Prefecture, Japan in the subtropical region of the northwest Pacific. The life cycle of the dinoflagellate consists of a dominant, attached, dome-shaped, vegetative form and short-lasting, motile cell. Asexual reproduction takes place by the formation of two motile cells within each non-motile cell. The released motile cells swim only for a short period and transform directly into the dome-shaped vegetative form. The duration of the cell cycle varies and can be extremely long, ranging 5-38days under culture conditions. The non-motile cell is enclosed by a cell wall and its surface is covered with many (80-130) spines of various length. The dinoflagellate is photosynthetic and contains many (more than 50) discoidal chloroplasts. Phylogenetic analysis reveals that the dinoflagellate is closely related to the type species of the genus Pyramidodinium, P. atrofuscum which also possesses a dominant, attached, non-motile form. However, P. spinulosum can be clearly distinguished from P. atrofuscum by the cell shape (dome-shaped vs. pyramid-shaped) and surface ornamentation (spines vs. wart-like processes) of the non-motile form. Based on these morphological differences together with molecular evidence, it was concluded that this organism from a deep water sand sample should be described as a second species of the genus Pyramidodinium, P. spinulosum.
  • Norico Yamada, Stuart D. Sym, Takeo Horiguchi
    MOLECULAR BIOLOGY AND EVOLUTION 34 (6) 1335 - 1351 0737-4038 2017/06 [Refereed][Not invited]
     
    Dinoflagellates are known to possess chloroplasts of multiple origins derived from a red alga, a green alga, haptophytes, or diatoms. The monophyletic "dinotoms" harbor a chloroplast of diatom origin, but their chloroplasts are polyphyletic belonging to one of four genera: Chaetoceros, Cyclotella, Discostella, or Nitzschia. It has been speculated that serial replacement of diatom-derived chloroplasts by other diatoms has caused this diversity of chloroplasts. Although previous work suggested that the endosymbionts of Nitzschia origin might not be monophyletic, this has not been seriously investigated. To infer the number of replacements of diatom-derived chloroplasts in dinotoms, we analyzed the phylogenetic affinities of 14 species of dinotoms based on the endosymbiotic rbcL gene and SSU rDNA, and the host SSU rDNA. Resultant phylogenetic trees revealed that six species of Nitzschia were taken up by eight marine dinoflagellate species. Our phylogenies also indicate that four separate diatom species belonging to three genera were incorporated into the five freshwater dinotoms. Particular attention was paid to two crucially closely related species, Durinskia capensis and a novel species, D. kwazulunatalensis, because they possess distantly related Nitzschia species. This study clarified that any of a total of at least 11 diatom species in five genera are employed as an endosymbiont by 14 dinotoms, which infers a more frequent replacement of endosymbionts in the world of dinotoms than previously envisaged.
  • Morphology and molecular phylogeny of the marine gregarine parasite Selenidium oshoroense n. sp. (Gregarina, Apicomplexa) isolated from a Northwest Pacific Hydroides ezoensis Okuda 1934 (Serpulidae, Polychaeta).
    Wakeman KC, Horiguchi T
    Marine Biodiversity doi.org/10.1007/s12526-017-064 2017/02 [Refereed][Not invited]
  • Sohail Keegan Pinto, Ryuta Terada, Takeo Horiguchi
    PHYCOLOGIA 56 (2) 136 - 146 0031-8884 2017 [Refereed][Not invited]
     
    A new marine benthic dinoflagellate, Testudodinium magnum sp. nov., was described from a sand sample collected on the seafloor at a depth of 35 m off Mageshima Island, Kagoshima, Japan. The dinoflagellate possessed the characteristic features of the genus Testudodinium, but was distinguished by its extremely large size and pebbled dorsal surface of the hyposome, caused by the presence of numerous nodules. The cells of this dinoflagellate possessed a dominant sessile and a rare motile form that were morphologically distinct from each other: The sessile form was larger and the small rounded episome with longitudinal furrow was completely embedded in the hyposome; the motile form was smaller and the episome was only partly embedded in the hyposome. The ultrastructural investigations revealed the presence of a large, circular, starch-sheathed pyrenoid whose matrix was traversed by randomly arranged thylakoid lamellae. The chloroplasts formed a network radiating outward from the pyrenoid. Uniquely, this dinoflagellate possessed internal props - structures that spanned the thickness of the cell and were fibrous in nature. The props were numerous and passed through organelles and cell contents. Phylogenetic analyses based on the small-subunit ribosomal DNA gene sequences placed this dinoflagellate firmly within the Testudodinium clade with high support. On the basis of the morphological features and phylogenetic analyses, we concluded that this dinoflagellate was a new species in the genus Testudodinium.
  • Kyoko Hagino, Naotaka Tomioka, Jeremy R. Young, Yoshihito Takano, Ryo Onuma, Takeo Horiguchi
    MARINE MICROPALEONTOLOGY 125 85 - 94 0377-8398 2016/05 [Refereed][Not invited]
     
    We have performed morphological and crystallographic studies of Braarudosphaera bigelowii using various light and electron microscopy techniques. A study by light microscopy revealed that B. bigelowii has a haptonema, and can use it for adhesion to external substrates. A study of the pentaliths by transmission electron microscopy indicates that the well-known trapezoidal lamina is formed with foliate crystals having perfectly identical crystallographic orientation. A cytological study shows that the pentaliths of B. bigelowii are surrounded by an organic structure consisting of a pentalith-substrate and thin organic layers. The pentalith-substrate underlies the proximal surface of the pentaliths and extends between the sides of the individual pentaliths, it also extends between the five trapezoidal segments forming a pentalith. Thin organic layers, which apparently originate from ridges of pentalith-substrate, cover the distal surface of the trapezoidal segments. The close association between the pentalith-substrate, organic layers, and pentaliths leads us to the hypothesis that calcification of the pentaliths occurs between the pentalith-substrate and organic layers, extracellularly. The relatively high Mg content observed in pentaliths supports our hypothesis of extracellular calcification. (C) 2016 Elsevier B.V. All rights reserved.
  • Gang Fu, Chikako Nagasato, Takahiro Yamagishi, Hiroshi Kawai, Kazuo Okuda, Yoshitake Takao, Takeo Horiguchi, Taizo Motomura
    PROTOPLASMA 253 (3) 929 - 941 0033-183X 2016/05 [Refereed][Not invited]
     
    Most swarmers (swimming cells) of the stramenopile group, ranging from unicellular protist to giant kelps (brown algae), have two heterogeneous flagella: a long anterior flagellum (AF) and a relatively shorter posterior flagellum (PF). These flagellated cells often exhibit phototaxis upon light stimulation, although the mechanism by which how the phototactic response is regulated remains largely unknown. A flavoprotein concentrating at the paraflagellar body (PFB) on the basal part of the PF, which can emit green autofluorescence under blue light irradiance, has been proposed as a possible blue light photoreceptor for brown algal phototaxis although the nature of the flavoprotein still remains elusive. Recently, we identified helmchrome as a PF-specific flavoprotein protein in a LC-MS/MS-based proteomics study of brown algal flagella (Fu et al. 2014). To verify the conservation of helmchrome, in the present study, the absence or presence and the localization of helmchrome in swarmers of various algal species were investigated. The results showed that helmchrome was only detected in phototactic swarmers but not the non-phototactic ones of the stramenopile group. Electron microscopy further revealed that the helmchrome detectable swarmers bear a conserved PFB-eyespot complex, which may serve as structural basis for light sensing. It is speculated that all three conserved properties: helmchrome, the PFB structure, and the eyespot apparatus, will be essential parts for phototaxis of stramenopile swarmers.
  • Tomoko Yuasa, Takeo Horiguchi, Shigeki Mayama, Osamu Takahashi
    JOURNAL OF PHYCOLOGY 52 (1) 89 - 104 0022-3646 2016/02 [Refereed][Not invited]
     
    The symbiotic dinoflagellate Gymnoxanthella radiolariae T. Yuasa et T. Horiguchi gen. et sp. nov. isolated from polycystine radiolarians is described herein based on light, scanning and transmission electron microscopy as well as molecular phylogenetic analyses of SSU and LSU rDNA sequences. Motile cells of G.radiolariae were obtained in culture, and appeared to be unarmored. The cells were 9.1-11.4m long and 5.7-9.4m wide, and oval to elongate oval in the ventral view. They possessed an counterclockwise horseshoe-shaped apical groove, a nuclear envelope with vesicular chambers, cingulum displacement with one cingulum width, and the nuclear fibrous connective; all of these are characteristics of Gymnodinium sensu stricto (Gymnodinium s.s.). Molecular phylogenetic analyses also indicated that G.radiolariae belongs to the clade of Gymnodinium s.s. However, in our molecular phylogenetic trees, G.radiolariae was distantly related to Gymnodinium fuscum, the type species of Gymnodinium. Based on the consistent morphological, genetic, and ecological divergence of our species with the other genera and species of Gymnodinium s.s., we considered it justified to erect a new, separate genus and species G.radiolariae gen. et sp. nov. As for the peridinioid symbiont ofradiolarians, Brandtodinium has been erected as a new genus instead of Zooxanthella, but the name Zooxanthella is still valid. Brandtodinium is a juniorsynonym of Zooxanthella. Our results suggest that at least two dinoflagellate symbiont species, peridinioid Zooxanthella nutricula and gymnodinioid G.radiolariae, exist in radiolarians, and that they may have been mixed and reported as Z.nutricula since the 19th century.
  • Ryo Onuma, Takeo Horiguchi
    PHYCOLOGICAL RESEARCH 64 (1) 35 - 43 1322-0829 2016/01 [Refereed][Not invited]
     
    The unarmoured dinoflagellate Nusuttodinium aeruginosum retains a kleptochloroplast, which is a transient chloroplast stolen from members of the cryptomonad genus, Chroomonas. Both N.aeruginosum and the closely related N.acidotum have been shown to restrict their diet to a limited number of species of this blue-green genus of cryptophyte. However, it is still unclear how flexible the predators are with regard to the ingestion and utilization of Chroomonas spp. as a source of kleptochloroplast. To address specificity of cryptomonad in N.aeruginosum, we collected the cells of N.aeruginosum from several ponds in Japan, and analysed the phylogeny of the kleptochloroplasts based on their plastidial 16S rDNA sequences. All sequences obtained in this study were restricted to only one (the subclade 4) of four subclades known to comprise the Chroomonas/Hemiselmis clade. Therefore, N.aeruginosum is specific in its dietary requirements, selecting their prey within the subclade level.
  • Norico Yamada, Ayumi Tanaka, Takeo Horiguchi
    JOURNAL OF PLANT RESEARCH 128 (6) 923 - 932 0918-9440 2015/11 [Refereed][Not invited]
     
    Compared to planktonic species, there is little known about the ecology, physiology, and existence of benthic dinoflagellates living in sandy beach or seafloor environments. In a previous study, we discovered 13(2),17(3)-cyclopheophorbide a enol (cPPB-aE) from sand-dwelling benthic dinoflagellates. This enol had never been detected in phytoplankton despite the fact that it is a chlorophyll a catabolite. We speculated from this discovery that habitat selection might be linked to pigment compositions in dinoflagellates. To test the hypothesis of habitat selection linking to pigment compositions, we conducted extensive analysis of pigments with high performance liquid chromatography (HPLC) for 40 species using 45 strains of dinoflagellates including three habitat types; sand-dwelling benthic forms, tidal pool inhabitants and planktonic species. The 40 dinoflagellates are also able to be distinguished into two types based on their chloroplast origins; red alga-derived secondary chloroplasts and diatom-derived tertiary ones. By plotting the pigments profiles onto three habitats, we noticed that twelve pigments including cPPB-aE were found to occur only in benthic sand-dwelling species of red alga-derived type. The similar tendency was also observed in dinoflagellates with diatom-derived chloroplasts, i.e. additional sixteen pigments including chl c (3) were found only in sand-dwelling forms. This is the first report of the occurrence of chl c (3) in dinoflagellates with diatom-derived chloroplasts. These results clarify that far greater diversity of pigments are produced by the dinoflagellates living in sand regardless of chloroplast types relative to those of planktonic and tidal pool forms. Dinoflagellates seem to produce a part of their pigments in response to their habitats.
  • Fernando Gomez, Ryo Onuma, Luis F. Artigas, Takeo Horiguchi
    EUROPEAN JOURNAL OF PHYCOLOGY 50 (2) 125 - 138 0967-0262 2015/05 [Not refereed][Not invited]
     
    The species Amphidinium eludens, as described by Herdman (1922; Proc. Trans. Liverpool Biol. Soc. 36: 18) based on her drawing in fig. 1, has been investigated for the first time by scanning electron microscopy and phylogenetic analysis. The morphological and molecular data reveal that this species is distantly related to other known dinoflagellates. Balech [1956, Rev. Algol., n. ser. 2(1-2): 30] cited Amphidinium eludens Herdman (1922, fig. 1) as the basionym of the type of Adenoides, while he described and illustrated Amphidinium kofoidii Herdman (1922, fig. 2) as Adenoides eludens. As the nomenclatural rules do not allow the change of basionym, we have re-defined the genus Adenoides based on the characteristics of Amphidinium eludens Herdman (1922, fig. 1). The thecal plate formula of Adenoides eludens is Po, 5, 6, 0c, 3+s, 5, 3p, 1. This species lacks a cingulum. The apical pore complex resembles that of peridinioid dinoflagellates, while the absence of a cingular groove is reminiscent of desmokont prorocentroids. We also propose Pseudadenoides kofoidii gen. & comb. nov. based on Herdman's 1922 fig. 2 of Amphidinium kofoidii which was described by Balech in 1956 and re-named Adenoides eludens.
  • Ryo Onuma, Takeo Horiguchi
    PROTIST 166 (2) 177 - 195 1434-4610 2015/05 [Refereed][Not invited]
     
    The unarmoured freshwater dinoflagellate Nusuttodinium (= Gymnodinium) aeruginosum retains a cryptomonad-derived kleptochloroplast and nucleus, the former of which fills the bulk of its cell volume. The paucity of studies following morphological changes to the kleptochloroplast with time make it unclear how the kleptochloroplast enlarges and why the cell ultimately loses the cryptomonad nucleus. We observed, both at the light and electron microscope level, morphological changes to the kleptochloroplast incurred by the enlargement process under culture conditions. The distribution of the cryptomonad nucleus after host cell division was also investigated. The volume of the kleptochloroplast increased more than 20-fold, within 120 h of ingestion of the cryptomonad. Host cell division was not preceded by cryptomonad karyokinesis so that only one of the daughter cells inherited a cryptomonad nucleus. The fate of all daughter cells originating from a single cell through five generations was closely monitored, and this observation revealed that the cell that inherited the cryptomonad nucleus consistently possessed the largest kleptochloroplast for that generation. Therefore, this study suggests that some important cryptomonad nucleus division mechanism is lost during ingestion process, and that the cryptomonad nucleus carries important information for the enlargement of the kleptochloroplast. (C) 2015 Elsevier GmbH. All rights reserved.
  • Kyoko Hagino, Jeremy R. Young, Paul R. Bown, Jelena Godrijan, Denise K. Kulhanek, Kazuhiro Kogame, Takeo Horiguchi
    MARINE MICROPALEONTOLOGY 116 28 - 37 0377-8398 2015/04 [Not refereed][Not invited]
     
    The extant coccolithophore Tergestiella adriatica Kamptner, which had not been reported since its original description in 1940, was recently re-discovered in coastal-nearshore waters at Tomari, Tottori (Japan) and offshore Rovinj (Croatia). Morphological analysis shows that extant Tergestiella and the Mesozoic genus Cyclagelosphaera (Watznaueriaceae), thought to have been extinct since the early Eocene (similar to 54 Ma), are virtually identical. Molecular phylogenetic study supports the inference that T. adriatica is a direct descendent of Cyclagelosphaera. It is therefore a remarkable example of a living fossil. Our documentation of patchy coastal distribution in living T. adriatica and records of rare occurrences of fossil Cyclagelosphaera in Oligocene-Miocene shallow water sediments, from the New Jersey shelf, suggest that Tergestiella/Cyclagelosphaera was restricted to nearshore environments during much of the Cenozoic. This restricted ecology explains the lack of fossil Tergestiella/ Cyclagelosphaera recorded in open ocean sediments deposited during the last 54 myr. Floristic study of coccolithophores in the coastal and offshore waters of Tomari over a six-year period, show that T. adriatica occurs synchronously with the unusual neritic species, Braarudosphaera bigelowii, in mid-June. The environmental factors that induce the co-occurrence of these two taxa are uncertain, and T. adriatica did not co-occur with B. bigelowii at any other sites. (C) 2015 Elsevier B.V. All rights reserved.
  • Shiho Hayakawa, Yasuharu Takaku, Jung Shan Hwang, Takeo Horiguchi, Hiroshi Suga, Walter Gehring, Kazuho Ikeo, Takashi Gojobori
    PLOS ONE 10 (3) e0118415  1932-6203 2015/03 [Refereed][Not invited]
     
    The ocelloid is an extraordinary eyespot organelle found only in the dinoflagellate family Warnowiaceae. It contains retina- and lens-like structures called the retinal body and the hyalosome. The ocelloid has been an evolutionary enigma because of its remarkable resemblance to the multicellular camera-type eye. To determine if the ocelloid is functionally photoreceptive, we investigated the warnowiid dinoflagellate Erythropsidinium. Here, we show that the morphology of the retinal body changed depending on different illumination conditions and the hyalosome manifests the refractile nature. Identifying a rhodopsin gene fragment in Erythropsidinium ESTs that is expressed in the retinal body by in situ hybridization, we also show that ocelloids are actually light sensitive photoreceptors. The rhodopsin gene identified is most closely related to bacterial rhodopsins. Taken together, we suggest that the ocelloid is an intracellular camera-type eye, which might be originated from endosymbiotic origin.
  • Ryo Onuma, Kunihiko Watanabe, Takeo Horiguchi
    PHYCOLOGIA 54 (2) 192 - 209 0031-8884 2015 [Not refereed][Not invited]
     
    Nusuttodinium spp. use ingested cryptomonad chloroplasts as kleptochloroplasts but form a sister group to Spiniferodinium spp., which are typical photosynthetic dinoflagellates. Our survey of the diversity of Nusuttodinium-related dinoflagellates resulted in the discovery of two colourless dinoflagellates, referred to as DAI (dinoflagellate collected from Aininkappu) and DIS (dinoflagellate collected from Ishikari). Cells of DAI possess a right-handed cingulum, an apical groove connecting with the sulcal extension at a right angle and nuclear chambers. Cells of DIS have a projection on their epicone encircled by a counterclockwise-directed apical groove and lack nuclear chambers. Cells of DAI digest cryptomonads directly, and DIS never ingests cryptomonads, making both species nonkleptochloroplastidic. Phylogenetic analyses showed that DIS is a member of the Nusuttodinium clade; whereas, DAI is a sister of the clade, and the photosynthetic genus Spiniferodinium is positioned at the base of these dinoflagellates. Based on a unique combination of features, including a unique shape to the apical groove, a right-handed cingulum, nuclear chambers and lack of a chloroplast, we describe DAI as Pellucidodinium psammophilum gen. & sp. nov. Based on a projection on the epicone, a counterclockwise-directed apical groove and the lack of nuclear chambers, we describe DIS as Nusuttodinium desymbiontum sp. nov. despite its inability to display kleptochloroplastidy. The phylogenetic position of P. psammophilum, together with its shared presence of nuclear chambers with Spiniferodinium, implies that it represents an evolutionary intermediate prior to the acquisition of kleptochloroplastidy; N. desymbiontum appears to have lost this competence secondarily.
  • Yoshihito Takano, Haruyo Yamaguchi, Isao Inouye, Ojvind Moestrup, Takeo Horiguchi
    PROTIST 165 (6) 759 - 778 1434-4610 2014/12 [Refereed][Not invited]
     
    Cells of five unarmoured kleptoplastidic dinoflagellates, Amphidinium latum, Amphidinium poecilochroum, Gymnodinium amphidinioides, Gymnodinium acidotum and Gymnodinium aeruginosum were observed under light and/or scanning electron microscopy and subjected to single-cell PCR. The SSU rDNA and the partial LSU rDNA of all the examined species were sequenced, and the SSU rDNA of G. myriopyrenoides was sequenced. Phylogenetic analyses revealed that the unarmoured kleptoplastidic species formed a monophyletic clade within the Gymnodinium- clade sensu Daugbjerg et al. (2000). The sister taxa for this clade were Gymnodinium palustre and Spiniferodinium galeiforme, both of which possess brown-coloured chloroplasts. The results indicated that acquisition of kleptoplastidy in these unarmoured dinoflagellates was a single event and that these unarmoured kleptoplastidic dinoflagellates may have evolved from a form with permanent chloroplasts. Molecular trees suggested that the acquisition of kleptoplastidy took place in a marine habitat and later some species colonized the freshwater habitat. Because these unarmoured kleptoplastidic dinoflagellates are monophyletic and characterized by distinct morphological and cytological features (including the presence of the same type of apical groove, absence of nuclear chambers in the nuclear envelope, absence of genuine chloroplasts, and the possession of kleptochloroplasts), we propose the establishment of a new genus, Nusuttodinium, to accommodate all these dinoflagellates. (C) 2014 Elsevier GmbH. All rights reserved.
  • Kunihiko Watanabe, Yukiko Miyoshi, Fumiyasu Kubo, Ryo Onuma, Shauna Murray, Takeo Horiguchi
    PHYCOLOGICAL RESEARCH 62 (2) 125 - 135 1322-0829 2014/04 [Not refereed][Not invited]
     
    A new heterotrophic sand-dwelling dinoflagellate, Ankistrodinium armigerum K. Watanabe, Miyoshi, Kubo, Murray et Horiguchi sp. nov., is described from Ishikari Beach, Hokkaido, Japan and Port Botany, NSW, Australia. The dinoflagellate is laterally compressed, possessing a short triangular epicone and a large sac-like hypocone. It possesses a right-handed cingulum and a deeply-incised sulcus. The sulcus descends towards the posterior of the cell where it becomes much deeper and wider, resulting in a bilobed ventral side to the hypocone, with a greater excavation of the left lobe than the right. In addition, the right lobe of the hypocone is shorter than the left lobe, which allows a partial view of the left sulcal wall when the cell is viewed from its right side. The sulcus ascends in the epicone to form an apical groove. The apical groove is linear but terminates in an ellipsoid fashion and its extremity approaches, but does not form a closed loop with the apical end of the linear portion. The dinoflagellate possesses two distinct size classes of trichocysts. The large trichocysts are located in the posterior part of the cell, while small trichocysts are distributed throughout the cell. The dinoflagellate shares morphological characteristics with the heterotrophic sand-dwelling dinoflagellate, Ankistrodinium semilunatum, the type species of the genus. These include a laterally compressed cell, a right-handed cingulum, a deeply-incised sulcus and the same basic structure to the apical groove. Molecular phylogenetic analyses based on small and large subunits of rDNA showed that in both trees, A. semilunatum and A. armigerum formed a robust clade, suggesting that these two species are closely related. Because no organism with the characteristics of this species exists and because this species is closely related to A. semilunatum, we concluded that this species should be described as a second species of the genus Ankistrodinium.
  • Kunihiko Watanabe, Yukiko Miyoshi, Fumiyasu Kubo, Ryo Onuma, Shauna Murray, Takeo Horiguchi
    PHYCOLOGICAL RESEARCH 62 (2) 125 - 135 1322-0829 2014/04 [Refereed][Not invited]
     
    A new heterotrophic sand-dwelling dinoflagellate, Ankistrodinium armigerum K. Watanabe, Miyoshi, Kubo, Murray et Horiguchi sp. nov., is described from Ishikari Beach, Hokkaido, Japan and Port Botany, NSW, Australia. The dinoflagellate is laterally compressed, possessing a short triangular epicone and a large sac-like hypocone. It possesses a right-handed cingulum and a deeply-incised sulcus. The sulcus descends towards the posterior of the cell where it becomes much deeper and wider, resulting in a bilobed ventral side to the hypocone, with a greater excavation of the left lobe than the right. In addition, the right lobe of the hypocone is shorter than the left lobe, which allows a partial view of the left sulcal wall when the cell is viewed from its right side. The sulcus ascends in the epicone to form an apical groove. The apical groove is linear but terminates in an ellipsoid fashion and its extremity approaches, but does not form a closed loop with the apical end of the linear portion. The dinoflagellate possesses two distinct size classes of trichocysts. The large trichocysts are located in the posterior part of the cell, while small trichocysts are distributed throughout the cell. The dinoflagellate shares morphological characteristics with the heterotrophic sand-dwelling dinoflagellate, Ankistrodinium semilunatum, the type species of the genus. These include a laterally compressed cell, a right-handed cingulum, a deeply-incised sulcus and the same basic structure to the apical groove. Molecular phylogenetic analyses based on small and large subunits of rDNA showed that in both trees, A. semilunatum and A. armigerum formed a robust clade, suggesting that these two species are closely related. Because no organism with the characteristics of this species exists and because this species is closely related to A. semilunatum, we concluded that this species should be described as a second species of the genus Ankistrodinium.
  • Norico Yamada, Ayumi Tanaka, Takeo Horiguchi
    JOURNAL OF PHYCOLOGY 50 (1) 101 - 107 0022-3646 2014/02 [Refereed][Not invited]
     
    Although chlorophyll degradation pathways in higher plants have been well studied, little is known about the mechanisms of chlorophyll degradation in microalgae. In this article, we report the occurrence of a chlorophyll a derivative that has never been discovered in photosynthetic organisms. This chlorophyll derivative emits no fluorescence and has a peculiar absorbance peak at 425, 451, 625, and 685nm. From these features, it was identified as 13(2),17(3)-cyclopheophorbide a enol (cPPB-aE), reported as a degradation product of chlorophyll a derived from prey algal cells in heterotrophic protists. We discovered cPPB-aE in six benthic photosynthetic dinoflagellates that are phylogenetically separated into four clades based on SSU rDNA molecular phylogeny. This is the first report of this chlorophyll derivative in photosynthetic organisms and we suggest that the derivative is used to quench excess light energy.
  • Kyoko Hagino, Ryo Onuma, Masanobu Kawachi, Takeo Horiguchi
    PLOS ONE 8 (12) e81749  1932-6203 2013/12 [Refereed][Not invited]
     
    Braarudosphaera bigelowii (Prymnesiophyceae) is a coastal coccolithophore with a long fossil record, extending back to the late Cretaceous (ca. 100 Ma). A recent study revealed close phylogenetic relationships between B. bigelowii, Chrysochromulina parkeae (Prymnesiophyceae), and a prymnesiophyte that forms a symbiotic association with the nitrogen-fixing cyanobacterium UCYN-A. In order to further examine these relationships, we conducted transmission electron microscopic and molecular phylogenetic studies of B. bigelowii. TEM studies showed that, in addition to organelles, such as the nucleus, chloroplasts and mitochondria, B. bigelowii contains one or two spheroid bodies with internal lamellae. In the 18S rDNA tree of the Prymnesiophyceae, C. parkeae fell within the B. bigelowii clade, and was close to B. bigelowii Genotype III (99.89% similarity). Plastid 16S rDNA sequences obtained from B. bigelowii were close to the unidentified sequences from the oligotrophic SE Pacific Ocean (e. g. HM133411) (99.86% similarity). Bacterial16S rDNA sequences obtained from B. bigelowii were identical to the UCYN-A sequence AY621693 from Arabian Sea, and fell in the UCYN-A clade. From these results, we suggest that; 1) C. parkeae is the alternate life cycle stage of B. bigelowii sensu stricto or that of a sibling species of B. bigelowii, and 2) the spheroid body of B. bigelowii originated from endosymbiosis of the nitrogen-fixing cyanobacterium UCYN-A.
  • Ryo Onuma, Takeo Horiguchi
    PROTIST 164 (5) 622 - 642 1434-4610 2013/09 [Refereed][Not invited]
     
    The unarmoured marine dinoflagellate Amphidinium poecilochroum and the unarmoured freshwater dinoflagellate Gymnodinium aeruginosum both belonging to the same clade, are known to possess cryptomonad-derived kleptochloroplasts. Previous studies revealed that G. aeruginosum can synchronise the division of the chloroplast with its own cell division while no simultaneous division takes place in A. poecilochroum, which is interpreted to mean that state of kleptochloroplastidy in G. aeruginosum is closer to that of the initial acquisition of the 'true chloroplast' within the lineage. Although the general ultrastructure of these two species has been reported, the changes in the kleptochloroplast with time have never been followed. We observed morphological changes in kleptochloroplasts of A. poecilochroum and G. aeruginosum following the ingestion of cryptomonad cells, using light and transmission electron microscopes. In A. poecilochroum, the cryptomonad ejectosomes, mitochondria and cytoplasm were all actively transferred into digestive vacuoles within 1 h of ingestion. The chloroplasts were deformed and the cryptomonad nucleus was digested after 3 h. By contrast, in G. aeruginosum, the cryptomonad cytoplasm and nucleus were retained for 24 h following ingestion, and the chloroplast was substantially enlarged. These differences imply that the retention of the cryptomonad nucleus is important for the maintenance of the chloroplast. (c) 2013 Elsevier GmbH. All rights reserved.
  • Norico Yamada, Ryuta Terada, Ayumi Tanaka, Takeo Horiguchi
    JOURNAL OF PHYCOLOGY 49 (3) 555 - 569 0022-3646 2013/06 [Refereed][Not invited]
     
    A new athecate dinoflagellate, Bispinodinium angelaceum N. Yamada et Horiguchi gen. et sp. nov., is described from a sand sample collected on the seafloor at a depth of 36m off Mageshima Island, subtropical Japan. The dinoflagellate is dorsiventrally compressed and axi-symmetric along the sulcus. The morphology resembles that of the genus Amphidinium sensu lato by having a small epicone that is less than one third of the total cell length. However, it has a new type of apical groove, the path of which traces the outline of a magnifying glass. The circular component of this path forms a complete circle in the center of the epicone and the straight handle runs from the sulcus to the circular component. Inside the cell, a pair of elongated fibrous structure termed here the spinoid apparatus extends from just beneath the circular apical groove to a point near the nucleus. Each of two paired structures consists of at least 10 hyaline fibers and this is a novel structure found in dinoflagellates. Phylogenetic analyses based on the SSU and LSU RNA genes did not show any high bootstrap affinities with currently known athecate dinoflagellates. On the basis of its novel morphological features and molecular signal, we conclude that this dinoflagellate should be described as a new species belonging to a new genus.
  • Tomoko Yuasa, Takeo Horiguchi, Shigeki Mayama, Atsushi Matsuoka, Osamu Takahashi
    SYMBIOSIS 57 (1) 51 - 55 0334-5114 2012/05 [Refereed][Not invited]
     
    Cyanobacterial symbionts were detected in the extracytoplasm of the polycystine radiolarian Dictyocoryne profunda Ehrenberg. The bacterial symbionts were observed as numerous spherical bodies similar to 0.5-1.0 mu m in diameter under transmission electron microscopy. They were present in a very restricted location close to the periphery of the host radiolarian shell, adjacent to the central capsular wall. Several cells of them may have been in the process of cell division or just divided. The symbionts had thylakoid-like structures, which ran around the cell periphery in two or three concentric layers. Based on the small subunit ribosomal DNA (16S rDNA) phylogenetic analyses, the intracellular symbiotic bacteria grouped with cyanobacteria belonging to the genus Synechococcus. Three sequences, one from each of three specimens of D. profunda, collected in March/October 2009 and March 2010 from the East China Sea, were the same and branched within Synechococcus clade II, that is characterized by strains with low amounts of phycourobilin (PUB).
  • Takeo Horiguchi, Maiko Tamura, Kazuhito Katsumata, Aika Yamaguchi
    PHYCOLOGICAL RESEARCH 60 (2) 137 - 149 1322-0829 2012/04 [Refereed][Not invited]
     
    A new genus of sand-dwelling photosynthetic dinoflagellate, Testudodinium Horiguchi, Tamura, Katsumata et A. Yamaguchi is proposed based on Testudodinium testudo (Herdman) Horiguchi, Tamura, Katsumata, et A. Yamaguchi comb. nov. (Basionym: Amphidinium testudo Herdman) and a new species in this new genus, Testudodinium maedaense Katsumata et Horiguchi sp. nov. is described. Amphidinium corrugatum is also transferred to this genus, making a new combination T. corrugatum (Larsen et Patterson) Horiguchi, Tamura et A. Yamaguchi. These three species are similar to the members of the genus Amphidinium in having an extremely small episome and a dorsoventrally flattened cell body. They are, however, distinguished from the genus Amphidinium seusu stricto by the possession of a distinct longitudinal furrow in the middle of ventral side of the episome. Phylogenetic trees based on small subunit (SSU) rDNA revealed that all three of these Testudodinium species formed a robust clade and, although statistical support is not high, the tree suggests Testudodinium clade is not closely related to Amphidinium seusu stricto clade. The morphological differences together with molecular data support the establishment of a new genus for A. testudo and its related species.
  • Satoko Sekida, Masaki Takahira, Takeo Horiguchi, Kazuo Okuda
    JOURNAL OF PHYCOLOGY 48 (1) 163 - 173 0022-3646 2012/02 [Refereed][Not invited]
     
    The possible role of cortical microtubules in dinoflagellates was studied using high-pressure treatments applied to nonmotile cells (just after ecdysis) of Scrippsiella hexapraecingula T. Horig. et Chihara. Whereas considerable disorganization of cortical microtubules was observed when cells were exposed to high-pressure treatments of 98 MPa or more for 515 min, they were mostly intact in cells exposed to a pressure of <98 MPa for 5 min. After nonmotile cells were exposed to high-pressure treatments sufficient to disorganize the cortical microtubules, they produced new motile cells with thecal plate patterns that differed considerably from the pattern known for this species. Increasing the intensity of high pressure applied to nonmotile cells resulted in an increase in the number of cells that exhibited disorganized cortical microtubules as well as a change in their thecal plate pattern, suggesting that high pressure disorganizes cortical microtubules leading to a change in the thecal plate pattern.
  • Takeo Horiguchi, Yusuke Hayashi, Hajime Kudo, Yoshiaki Hara
    PHYCOLOGIA 50 (6) 616 - 623 0031-8884 2011/11 [Refereed][Not invited]
     
    A new benthic dinoflagellate Spiniferodinium palauense Horiguchi, Hayashi, Kudo & Hara sp. nov. is described from the marine lake, Uet era Ongael, on Ongael Island, Koror, Republic of Palau. The genus Spiniferodinium is unique in that the benthic non-motile formpossesses a helmet-shaped cell covering, termed the 'helmet shell', which is rigid, transparent and covered in many small regularly-distributed spines and covers the entire protoplasm. The dinoflagellate reproduces asexually by the formation of Gymnodinium-like motile cells within the helmet shell. The released motile cells directly return to the non-motile state by forming the helmet shell. The dinoflagellate from Palau is the second species for the genus and shares these characteristics. However, the new species is distinguished from the type species, Spiniferodinium galeiforme, in having a thinner cell body, a smaller epicone, a right-handed cingulum and a different type of spine on the shell. Phylogenetic analyses based on small subunit ribosomal RNA gene (SSU rDNA) sequences indicated that Spiniferodinium galeiforme and Spiniferodinium palauense formed a strongly-supported clade, suggesting these are closely related. However, Their SSU rDNA sequences differ by 22 base pairs, indicating they are distinct species. Our phylogenetic tree suggests that these unique benthic dinoflagellates evolved within the Gymnodinium clade sensu stricto.
  • Kyoko Hagino, El Mahdi Bendif, Jeremy R. Young, Kazuhiro Kogame, Ian Probert, Yoshihito Takano, Takeo Horiguchi, Colomban de Vargas, Hisatake Okada
    JOURNAL OF PHYCOLOGY 47 (5) 1164 - 1176 0022-3646 2011/10 [Refereed][Not invited]
     
    Emiliania huxleyi (Lohmann) W. W. Hay et H. Mohler is a cosmopolitan coccolithophore occurring from tropical to subpolar waters and exhibiting variations in morphology of coccoliths possibly related to environmental conditions. We examined morphological characters of coccoliths and partial mitochondrial sequences of the cytochrome oxidase 1b (cox1b) through adenosine triphosphate synthase 4 (atp4) genes of 39 clonal E. huxleyi strains from the Atlantic and Pacific Oceans, Mediterranean Sea, and their adjacent seas. Based on the morphological study of culture strains by SEM, Type O, a new morphotype characterized by coccoliths with an open central area, was separated from existing morphotypes A, B, B/C, C, R, and var. corona, characterized by coccoliths with central area elements. Molecular phylogenetic studies revealed that E. huxleyi consists of at least two mitochondrial sequence groups with different temperature preferences/tolerances: a cool-water group occurring in subarctic North Atlantic and Pacific and a warm-water group occurring in the subtropical Atlantic and Pacific and in the Mediterranean Sea.
  • Aika Yamaguchi, Mona Hoppenrath, Vera Pospelova, Takeo Horiguchi, Brian S. Leander
    EUROPEAN JOURNAL OF PHYCOLOGY 46 (2) 98 - 112 0967-0262 2011 [Refereed][Not invited]
     
    Herdmania litoralis is a heterotrophic, sand-dwelling dinoflagellate with morphological characters that do not provide clear evidence for its systematic position in any existing family of dinoflagellates. Protoperidinium minutum is a heterotrophic, planktonic species that has a typical tabulation for the genus Protoperidinium. In order to infer the phylogenetic positions of these two species more confidently, we characterized the thecal plate patterns and determined small-subunit and large-subunit ribosomal DNA sequences (SSU rDNA and LSU rDNA, respectively) from both species. Intraindividual and intraspecific diversity of SSU and LSU rDNA data were characterized in H. litoralis using a combination of single-cell PCR approaches and analyses of PCR clones derived from multi-cell DNA extractions. The results of the molecular phylogenetic analyses demonstrated a novel, well-supported clade comprising both sand-dwelling species (H. litoralis and Thecadinium dragescoi) and planktonic species (P. minutum). Because the establishment of this clade also demonstrated that P. minutum is not a member of Protoperidinium, we reinstated and emended the genus Archaeperidinium Jorgensen 1912.
  • SHAH Md. Mahfuzur Rahman, REIMER James, Davis, REIMER James Davis, HORIGUCHI Takeo, SUDA Shoichiro
    Galaxea 12 (1) 49  1883-0838 2010/06 [Refereed][Not invited]
  • AMO Miki, SUZUKI Noriyuki, KAWAMURA Hiroshi, YAMAGUCHI Aika, TAKANO Yoshihito, HORIGUCHI Takeo
    Geochem J 44 (3) 225 - 231 0016-7002 2010 [Refereed][Not invited]
  • Maiko Tamura, Yoshihito Takano, Takeo Horiguchi
    PHYCOLOGICAL RESEARCH 57 (4) 304 - 312 1322-0829 2009/12 [Refereed][Not invited]
     
    P>A new species of Amphidinium, A. cupulatisquama Tamura et Horiguchi, from sand samples from Ikei Island, Okinawa Prefecture in subtropical Japan, is described based on light, scanning and transmission electron microscopy and the partial sequencing of the large subunit rDNA gene. The species has a typical morphology for the genus, but is distinguished from previously described species by having a combination of the following characteristics: (i) a relatively large cell (over 30 mu m in length); (ii) possessing an eyespot on the dorsal side of the cingulum; (iii) the longitudinal flagellum emerging from a point close to the cingulum; (iv) cell division taking place in the motile phase; and (v) possessing body scales. This is the third species of this genus to possess body scales. The body scales of A. cupulatisquama are uniform and cup-shaped in side view and elliptical in face view. Their dimensions are 136.4 nm by 91.0 nm by 81.8 nm high. In side view, the scale is seen to have a thick lower half and a thin upper half. This scale type is very different from those of previously reported Amphidinium species (HG114 and HG115). The molecular tree indicated that A. cupulatisquama and the two other strains of body scale-bearing Amphidinium are distantly related within the Amphidinium clade.
  • Kyoko Hagino, Yoshihito Takano, Takeo Horiguchi
    MARINE MICROPALEONTOLOGY 72 (3-4) 210 - 221 0377-8398 2009/09 [Not refereed][Not invited]
     
    Partial SSU rDNA sequences were obtained from 13 naturally collected cells of Braarudosphaera bigelowii obtained from various parts of seas surrounding Japan. Together with the two previously reported sequences, 15 specimens were classified into five SSU rDNA Genotypes I-V. Based on the side length of the pentaliths forming the coccosphere, these specimens were also classified into three size-morphotypes: Intermediate form-A, Intermediate form-B, and Large form. Genotypes of B. bigelowii were well correlated with size-morphotypes but not with sampling area. This result indicates that size differences in B. bigelovvii are the results of speciation and not of intra-population variety. Therefore, Genotypes I and II (Intermediate form-A) and Genotypes IV and V (Large form) are regarded as pseudo-cryptic sibling species of typical B. bigelowii (Genotype III, Intermediate form-B), which corresponds to the original description of the species. From the SSU rDNA sequences, it is evident that Genotype V arose from Genotype IV, and Genotype IV originated from Genotype III. The specimens of Genotypes III-V showed size increase of pentaliths in accordance with their branching order. The consistency in the relationship between genotypes and size-morphotypes of living B. bigelowii-complex observed in this study suggests that inconsistency of size range of 'B. bigelowii pentaliths among different geological ages reported by palaeontological studies stems from additional pseudo-cryptic speciation in the lineage of 'B. bigelowii' in the geological past. (C) 2009 Elsevier B.V. All rights reserved.
  • Sohiko Kameyama, Urumu Tsunogai, Fumiko Nakagawa, Motoki Sasakawa, Daisuke D. Komatsu, Akira Ijiri, Junko Yamaguchi, Takeo Horiguchi, Hiroshi Kawamura, Aika Yamaguchi, Atsushi Tsuda
    MARINE CHEMISTRY 115 (1-2) 92 - 101 0304-4203 2009/06 [Refereed][Not invited]
     
    During the Subarctic Pacific Iron Experiment for Ecosystem Dynamics Study II (SEEDS-II), we monitored variations in the concentrations of non-methane hydrocarbons (NMHCs), CH3Cl. N2O. and CH4 within a phytoplankton bloom. Stable isotopic compositions were also determined to evaluate the sources of the variations. Although there was little variation in either the concentrations or the stable isotopic compositions of alkenes, CH3Cl, N2O. and CH4 during the 23-day observation period, alkane concentrations increased substantially as the phytoplankton bloomed. The column-integrated quantities of alkanes increased to 3 times pre-bloom levels for C2H6, 5 times for C3H8. and 20 times for n-C4H10. The delta C-13 values of both C2H6 and C3H8 remained almost constant while concentrations increased, whereas that of n-C4H10 increased by about 12 parts per thousand. To evaluate the sources of the alkanes produced during the bloom, we compared their delta C-13 values with those of alkanes produced in axenic phytoplankton cultures in our laboratory. We concluded that during the SEEDS-II experiment the major portions of C2H6 and C3H8 were produced during the autolysis of diatoms cells, whereas n-C4H10 was produced during autolysis of other phytoplankton cells such as cryptophytes and dinoflagellates. (C) 2009 Elsevier B.V. All rights reserved.
  • OHTSUKA Susumu, HANAMURA Yukio, HORIGUCHI Takeo, YAMAGUCHI Atsushi, SHIMOMURA Michitaka, SUZAKI Toshinobu
    日本甲殻類学会大会講演要旨集 47th 36  2009 [Not refereed][Not invited]
  • Aika Yamaguchi, Takeo Horiguchi
    JOURNAL OF PHYCOLOGY 44 (4) 1090 - 1092 0022-3646 2008/08 [Refereed][Not invited]
     
    The genus Protoperidinium is an assemblage of heterotrophic dinoflagellates, several species of which have been successfully cultured in the past using various photosynthetic algae as a food source. We succeeded in culturing Protoperidinium crassipes (Kof.) Balech on three separate occasions for periods ranging from 2 to 21 months using rice flour as a food source. In these cultures, unusual small types of cells that were never observed to actively feed sometimes appeared. We confirmed that P. crassipes in culture exhibited bioluminescence.
  • Haruyo Yamaguchi, Mona Hoppenrath, Kiyotaka Takishita, Takeo Horiguchi
    PHYCOLOGICAL RESEARCH 56 (2) 127 - 138 1322-0829 2008/06 [Refereed][Not invited]
     
    A new species of the Raphidophyceae, Haramonas pauciplastida sp. nov. from Canada is described. The genus Haramonas has been described based on the type species Haramonas dimorpha and currently only two species are known. This new alga belongs to the genus because it possesses a tubular invagination at the posterior end of the cell, producing a large amount of mucilage and generating both motile and non-motile phases in its life cycle. The chloroplast color of H. pauciplastida is yellowish green, and is similar to that of Haramonas viridis Horiguchi et Hoppenrath. However, this alga differs from the other species of the genus in that it possesses fewer chloroplasts, which are rarely overlapping. The ultrastructual study shows differences between these two species in the number of thylakoids in the lamella, the presence of a scattered pyrenoid matrix, and the position of the plastoglobuli. The phylogenetic analyses of the small subunit ribosomal RNA gene from the Haramonas species reveal that three species can be distinguished genetically from each other and they form a robust clade in the Raphidophyceae. This result supports the notion that the characteristic features of Haramonas are synapomorphies. This is the first report of molecular data from the Haramonas species.
  • Yoshihito Takano, Gert Hansen, Daisuke Fujita, Takeo Horiguchi
    PHYCOLOGIA 47 (1) 41 - 53 0031-8884 2008/01 [Refereed][Not invited]
     
    Two freshwater armoured dinoflagellates, Peridiniopsis cf. kevei from Japan and Peridiniopsis penardii from Japan and Italy, were examined by means of light, scanning and transmission electron microscopy. Morphological studies indicated that the two dinoflagellates had similar type of cellular structure and possessed an endosymbiotic diatom. The diatom endosymbiont, which contained a eukaryotic nucleus, chloroplasts and mitochondria, was separated from the dinoflagellate cytoplasm by a single unit membrane. The dinoflagellate cytoplasm contained a triple-membrane-bound lid eyespot, in addition to typical dinoflagellate organelles. Molecular phylogenetic analyses based on small Subunit ribosomal RNA gene (SSU rDNA) revealed a close relationship between these two dinoflagellates. They formed a clade with other dinoflagellates possessing a diatom endosymbiont, suggesting a single origin of diatom-harbouring dinoflagellates. On the contrary, the phylogenetic analyses based on plastid-encoded rbcL and nuclear-encoded SSU rDNA of the endosymbionts included the endosymbiont of these two freshwater dinoflagellates in the Thalassiosiral Skeletonema-clade (Centrales), whereas the endosymbionts of other diatom-containing dinoflagellates, except for Peridinium quinquecorne, were closely related to members of the Bacillariaceae (Pennales), most likely a Nitzschia-like diatom. The discrepancy between the host phylogeny and the endosymbiont phylogeny suggested, as in the case of Peridinium quinquecorne, that there was a serial replacement of endosymbionts from original a pennate Nitzschia-like diatom to a centric diatom, such as Thalassiosira (or possibly Skeletonema).
  • SHIMADA Satoshi, EBATA Hiroki, HORIGUCHI Takeo, KURIHARA Akira, TANAKA Jiro
    植物研究雑誌 82 (4) 190-204  0022-2062 2007/08 [Refereed][Not invited]
  • Ai Harada, Susumu Ohtsuka, Takeo Horiguchi
    PROTIST 158 (3) 337 - 347 1434-4610 2007/07 [Refereed][Not invited]
     
    Small subunit ribosomal RNA gene sequences of Duboscquella spp. infecting the tintinnid ciliate, Favella ehrenbergii, were determined. Two parasites were sampled from different localities. They are morphologically similar to each other and both resemble D. aspida. Nevertheless, two distinct sequences (7.6% divergence) were obtained from them. Phylogenetic trees inferred from maximum likelihood and maximum parsimony revealed that these two Duboscquella spp. sequences are enclosed in an environmental clade named Marine Alveolate Group 1. This clade consists of a large number of picoplanktonic organisms known only from environmental samples from various parts of the ocean worldwide, and which therefore lack clear characterization and identification. Here, we provide morphological and genetic characterization of these two Duboscquella genotypes included in this enigmatic clade. Duboscquella spp. produce a large number of small flagellated spores as dispersal agents and the presence of such small cells partially explains why the organisms related to these parasites have been detected within environmental genetic libraries, built from picoplanktonic size fractions of environmental samples. The huge diversity of the Marine Alveolate Group I and the finding that parasites from different marine protists belong to this lineage suggest that parasitism is a widespread and ecologically relevant phenomenon in the marine environment. (c) 2007 Elsevier GmbH. All rights reserved.
  • Mona Hoppenrath, Takeo Horiguchi, Yukiko Miyoshi, Marina Selina, Max' F. J. R. Taylor, Brian S. Leander
    PHYCOLOGICAL RESEARCH 55 (2) 159 - 175 1322-0829 2007/06 [Refereed][Not invited]
     
    Samples of Sabulodinium undulatum Saunders et Dodge, the type species of the monospecific genus, were collected and characterized from Germany, Russia, Japan and Canada. This species has a laterally flattened, oval cell with a truncated apex and a dorsally pointing small episome. The dorsal margin of the hyposome has an undulating shape. A dorsal spine and/or antapical spine are sometimes present. The specimens of this heterotrophic species are 27.5-42.5 mu m long and 18.5-36.0 mu m wide, and have a theca with the plate arrangement apical pore complex (APC) 5' 1a 6' 5c 4s 6''' 1''''. The shape of the dorsal theca is variable. The species distribution seems to be restricted to northern temperate regions. Sabulodinium undulatum occurred in all sandy eulittoral areas throughout the year and was also present in sandy sublittoral and supralittoral (beach) samples. The species can tolerate a broad range of temperatures and salinities. Sabulodinium occurred from -2.0 to +24.3 degrees C and 4-35 salinity. It is likely that the observed variability in morphology and habitat reflect several varieties. We propose to establish three varieties within the species, namely S. undulatum var. undulatum, S. undulatum var. glabromarginatum, and S. undulatum var. monospinum. The systematic position of Sabulodinium is discussed in the context of comparative morphological and molecular phylogenetic data.
  • Aika Yamaguchi, Hiroshi Kawamura, Takeo Horiguchi
    PHYCOLOGIA 46 (3) 270 - 276 0031-8884 2007/05 [Refereed][Not invited]
     
    Protoperidinium bipes is a minute heterotrophic dinoflagellate with a very distinctive shape and a tabulation unique for the genus, resulting in its placement into the subgenus Minusculum. The small subunit rDNA and the large subunit rDNA sequences of this species were determined using the single-cell polymerase chain reaction technique and analyzed to estimate its phylogenetic position. The results of the phylogenetic analyses revealed that P. bipes positioned in the clade corresponding to the section Protoperidinium of the subgenus Protoperidinium. Although the species occasionally has been regarded to belong to a different genus, our molecular analysis clearly confirmed that it is a true member of the genus Protoperidinium. It was inferred from our analysis that the reduction of the number of precingular plates took place relatively recently during the course of evolution of Protoperidinium.
  • Richard N. Pienaar, Hiroto Sakai, Takeo Horiguchi
    JOURNAL OF PLANT RESEARCH 120 (2) 247 - 258 0918-9440 2007/03 [Refereed][Not invited]
     
    A new dinoflagellate Durinskia capensis Pienaar, Sakai et Horiguchi sp. nov. (Peridiniales, Dinophyceae), from tidal pools along the west coast of the Cape Peninsula, Republic of South Africa, is described. The dinoflagellate produces characteristic dense orange-red colored blooms in tidal pools. The organism is characterized by having a eukaryotic endosymbiotic alga. Ultrastructure study revealed the organism has a cellular construction similar to that of other diatom-harboring dinoflagellates. The cell is thecate and the plate formula is: Po, x, 4', 2a, 6", 5c, 4s, 5'", 2"", which is the same as that of Durinskia baltica, the type species of the genus Durinskia. D. capensis can, however, be distinguished from D. baltica by overall cell shape, the relative size of the 1a and 2a plates, the degree of cingular displacement, and the shape of the eyespot. Our molecular analysis based on SSU rDNA revealed that D. capensis is closely allied to D. baltica, thus supporting the assignment of this new species to this genus. This Durinskia clade takes a sister position to another diatom-harboring dinoflagellate clade, which includes Kryptoperidinium foliaceum and Galeidinium rugatum. Molecular analysis based on the rbcL gene sequence and ultrastructure study revealed that the endosymbiont of D. capensis is a diatom. The SSU rDNA gene trees indicated that four species with a diatom endosymbiont formed a clade, suggesting a single endosymbiotic origin.
  • Takeo Horiguchi
    Paleontological Research 10 (4) 299 - 309 1342-8144 2006/12/31 [Refereed][Not invited]
     
    This account firstly outlines the relationships between algal diversity and chloroplast acquisition through endosymbiosis. Secondly, it briefly reviews chloroplast diversity in dinoflagellates. Particular emphasis is placed on the evolutionary process in the small but interesting group of dinoflagellates that possess a diatom endosymbiont. © by the Palaeontological Society of Japan.
  • YAMAGUCHI Aika, KAWAMURA Hiroshi, HORIGUCHI Takeo
    Phycol Res 54 (4) 317 - 329 1322-0829 2006/12 [Refereed][Not invited]
  • HORIGUCHI Takeo, TAKANO Yoshihito
    Phycol Res 54 (3) 193 - 200 1322-0829 2006/09 [Refereed][Not invited]
  • Y Takano, T Horiguchi
    JOURNAL OF PHYCOLOGY 42 (1) 251 - 256 0022-3646 2006/02 [Refereed][Not invited]
     
    We have developed a useful method to obtain light and scanning electron micrographs of a single dinoflagellate cell, prior to applying the cell to the single cell PCR technique. This method allows us to record detailed morphological information on any cell used for sequencing, which can be extremely important for the future identification of the organism, because cells used for single cell PCR usually cannot be retained. Furthermore, by applying multiple sets of PCR primers at the same time, we have successfully amplified and sequenced multiple genes (and DNA regions) simultaneously, even from a single cell. In this note, we demonstrate the methods of this technique by using two different types of dinoflagellates, i.e. an armored freshwater species, Peridinium willei Huitfeld-Kaas, and an unarmored marine species, Akashiwo sanguinea (Hirasaka) Hansen and Moestrup. By rotating the cell, photographs of all aspects of a single cell can be taken even using the SEM. The genes and DNA regions sequenced in these examples include a region of the ribosomal DNA (SSU, ITS1, 5.8S, ITS2, and part of the LSU) as well as part of the mitochondrial DNA-encoded gene, cox1. This technique can be applied to both photosynthetic and heterotrophic dinoflagellates and will accelerate biodiversity studies.
  • SEKIDA Satoko, HORIGUCHI Takeo, OKUDA Kazuo
    J Plant Res 118 (Supplement) 143  0918-9440 2005/12 [Refereed][Not invited]
  • HORIGUCHI Takeo, SUKIGARA Chisa
    Phycol Res 53 (4) 247 - 254 1322-0829 2005/12 [Refereed][Not invited]
  • TAMURA Maiko, IWATAKI Mitsunori, HORIGUCHI Takeo
    Phycol Res 53 (4) 303 - 311 1322-0829 2005/12 [Refereed][Not invited]
  • YAMAGUCHI Aika, HORIGUCHI Takeo
    Phycol Res 53 (1) 30 - 42 1322-0829 2005/03 [Refereed][Not invited]
  • 渦鞭毛藻類に見られる細胞内共生の多様性と進化。
    日本植物分類学会会報 11 (2) 59 - 74 1996 [Not refereed][Not invited]
  • シワランソウモドキCollinsiella cava(Yendo)Printz(緑藻,ランソウモドキ科)の粘質様物質-構成する中性糖類を中心として-(共著)
    藻類 37,291-294 1989 [Not refereed][Not invited]

Books etc

  • Susumu Ohtsuka, Toshinobu Suzaki, Takeo Horiguchi, Noritoshi Suzuki, Fabrice Not 
    Springer 2015/09 (ISBN: 4431551298) 648
  • Hoppenrath Mona, Murray Shauna A, Chomérat Nicolas, Horiguchi Takeo 
    Schweizerbart 2014 (ISBN: 9783510614028)
  • 藻類の多様性と系統(共著)
    裳華房 1999
  • 藻類の生活史集成 第3巻 (共著)
    内田老鶴圃 1993
  • 日本の赤潮生物-写真と解説-(共著)
    内田老鶴圃 1990
  • Red tide organisms in Japan : An illustrated taxonomic guide.
    1990

MISC

  • 萩野恭子, 大沼亮, 高野義人, 富岡尚敬, 堀口健雄  月刊海洋  115‐124  2017/07/01  [Not refereed][Not invited]
  • KEEGAN Pinto Sohail, TERADA Ryuta, HORIGUCHI Takeo  藻類  65-  (1)  58  2017/03/10  [Not refereed][Not invited]
  • DAWUT Mahmutjan, SYM Stuart D, SUDA Shoichiro, HORIGUCHI Takeo  藻類  64-  (1)  49  2016/03/10  [Not refereed][Not invited]
  • PINTO Sohail Keegan, TERADA Ryuta, HORIGUCHI Takeo  藻類  64-  (1)  48  2016/03/10  [Not refereed][Not invited]
  • 萩野恭子, 富岡尚敬, YOUNG Jeremy R, 高野義人, 大沼亮, 堀口健雄  藻類  64-  (1)  52  2016/03/10  [Not refereed][Not invited]
  • 池田彬人, 堀口健雄  藻類  64-  (1)  80  2016/03/10  [Not refereed][Not invited]
  • KEEGAN Pinto Sohail, TERADA Ryuta, HORIGUCHI Takeo  藻類  63-  (1)  72  2015/03/10  [Not refereed][Not invited]
  • IKEDA AKITO, HORIGUCHI TAKEO  藻類  63-  (1)  74  2015/03/10  [Not refereed][Not invited]
  • ONUMA RYO, HORIGUCHI TAKEO  藻類  63-  (1)  77  2015/03/10  [Not refereed][Not invited]
  • KEEGAN PINTO Sohail, YAMADA Norico, TANAKA Ayumi, TERADA Ryuta, HORIGUCHI Takeo  日本植物学会大会研究発表記録  78th-  154  2014/09/01  [Not refereed][Not invited]
  • GEN Clark, TAMURA Maiko, HORIGUCHI Takeo  藻類  62-  (1)  72  2014/03/10  [Not refereed][Not invited]
  • ONUMA RYO, HORIGUCHI TAKEO  藻類  62-  (1)  53  2014/03/10  [Not refereed][Not invited]
  • YAMADA NORIKO, TANAKA AYUMI, TAKAICHI SHIN'ICHI, HORIGUCHI TAKEO  藻類  62-  (1)  48  2014/03/10  [Not refereed][Not invited]
  • YAMAGUCHI AIKA, WATANABE KUNIHIKO, HORIGUCHI TAKEO, HOPPENRATH MONA, KAWAI HIROSHI  藻類  62-  (1)  71  2014/03/10  [Not refereed][Not invited]
  • SHIMANO SATOSHI, SUZUKI NORITOSHI, OGANE KAORU, ISHITANI YOSHIYUKI, UJIIE YURIKA, HORIGUCHI TAKEO  日本生態学会大会講演要旨(Web)  61st-  WEB ONLY T04-3  2014  [Not refereed][Not invited]
  • HANDA SHINJI, HORIGUCHI TAKEO, OMURA YOSHIHITO, HIGUCHI MASANOBU  Hikobia  16-  (3)  311  -314  2013/12/27  [Not refereed][Not invited]
  • 山田規子, 田中歩, SYM Stuart D, 堀口健雄  日本植物学会大会研究発表記録  77th-  174  2013/08/20  [Not refereed][Not invited]
  • 渡邊邦彦, 堀口健雄  藻類  61-  (1)  60  2013/03/10  [Not refereed][Not invited]
  • 大沼亮, 渡邊邦彦, 堀口健雄  藻類  61-  (1)  60  2013/03/10  [Not refereed][Not invited]
  • 萩野恭子, YOUNG Jeremy R, BOWN Paul R, GODRIJAN Jelena, 小亀一弘, KULHANEK Denise K, 堀口健雄  藻類  60-  (2)  91  2012/07/10  [Not refereed][Not invited]
  • 関田諭子, 堀口健雄, 奥田一雄  藻類  60-  (2)  95  2012/07/10  [Not refereed][Not invited]
  • 渡邊邦彦, 大沼亮, 堀口健雄  藻類  60-  (2)  113  2012/07/10  [Not refereed][Not invited]
  • 山田規子, 寺田竜太, 堀口健雄  藻類  60-  (2)  113  2012/07/10  [Not refereed][Not invited]
  • 堀口健雄  Program Abstr Book Annu Meet Jpn Soc Dev Biol  45th-  311  2012/04/27  [Not refereed][Not invited]
  • 高野義人, 岩滝光儀, 堀口健雄, 松岡數充  日本ベントス学会・日本プランクトン学会合同大会講演要旨集  2011-  137  2011/09/16  [Not refereed][Not invited]
  • 萩野恭子, BENDIF El Mahdi, YOUNG Jeremy R, 小亀一弘, PROBERT Ian, 高野義人, 堀口健雄, DE VARGAS Colomban, 岡田尚武  日本植物学会大会研究発表記録  75th-  158  2011/09/10  [Not refereed][Not invited]
  • 山田規子, 堀口健雄  藻類  59-  (1)  71  2011/03/10  [Not refereed][Not invited]
  • 大沼亮, 原慶明, 堀口健雄  藻類  59-  (1)  54  2011/03/10  [Not refereed][Not invited]
  • HAGINO KYOKO, HORIGUCHI TAKEO, TAKANO YOSHIHITO, MATSUOKA HIROMI  日本プランクトン学会報  58-  (1)  73-80  2011/02/26  [Not refereed][Not invited]
  • HORIGUCHI TAKEO  日本プランクトン学会報  58-  (1)  32-39  2011/02/26  [Not refereed][Not invited]
  • 堀口健雄  日本海洋学会大会講演要旨集  2010-  284  2010/03/15  [Not refereed][Not invited]
  • 萩野恭子, 高野義人, 堀口健雄  日本海洋学会大会講演要旨集  2010-  290  2010/03/15  [Not refereed][Not invited]
  • 花房友香里, 高野義人, 堀口健雄  藻類  58-  (1)  53  2010/03/10  [Not refereed][Not invited]
  • 高野義人, 岩滝光儀, 堀口健雄, 松岡數充  藻類  58-  (1)  54  2010/03/10  [Not refereed][Not invited]
  • 高睿瑞, 堀口健雄  藻類  58-  (1)  34  2010/03/10  [Not refereed][Not invited]
  • 花房友香里, 堀口健雄  日本植物学会大会研究発表記録  73rd-  173  2009/09/17  [Not refereed][Not invited]
  • 湯浅智子, 堀口健雄, 真山茂樹, 高橋修  日本古生物学会年会講演予稿集  2009-  71  2009/06/26  [Not refereed][Not invited]
  • 石黒公章, 大塚攻, 堀口健雄  藻類  57-  (1)  66  2009/03/10  [Not refereed][Not invited]
  • 花房友香里, 堀口健雄  藻類  57-  (1)  74  2009/03/10  [Not refereed][Not invited]
  • 湯浅智子, 堀口健雄, 真山茂樹, 高橋修  藻類  57-  (1)  72  2009/03/10  [Not refereed][Not invited]
  • 山中真理子, 堀口健雄  藻類  57-  (1)  66  2009/03/10  [Not refereed][Not invited]
  • 山口愛果, 関田諭子, 津田正史, 堀口健雄  藻類  56-  (1)  78  2008/03/10  [Not refereed][Not invited]
  • Ai Harada, Susumu Ohtsuka, Takeo Horiguchi  PROTIST  158-  (3)  337  -347  2007/07  [Not refereed][Not invited]
     
    Small subunit ribosomal RNA gene sequences of Duboscquella spp. infecting the tintinnid ciliate, Favella ehrenbergii, were determined. Two parasites were sampled from different localities. They are morphologically similar to each other and both resemble D. aspida. Nevertheless, two distinct sequences (7.6% divergence) were obtained from them. Phylogenetic trees inferred from maximum likelihood and maximum parsimony revealed that these two Duboscquella spp. sequences are enclosed in an environmental clade named Marine Alveolate Group 1. This clade consists of a large number of picoplanktonic organisms known only from environmental samples from various parts of the ocean worldwide, and which therefore lack clear characterization and identification. Here, we provide morphological and genetic characterization of these two Duboscquella genotypes included in this enigmatic clade. Duboscquella spp. produce a large number of small flagellated spores as dispersal agents and the presence of such small cells partially explains why the organisms related to these parasites have been detected within environmental genetic libraries, built from picoplanktonic size fractions of environmental samples. The huge diversity of the Marine Alveolate Group I and the finding that parasites from different marine protists belong to this lineage suggest that parasitism is a widespread and ecologically relevant phenomenon in the marine environment. (c) 2007 Elsevier GmbH. All rights reserved.
  • Mona Hoppenrath, Takeo Horiguchi, Yukiko Miyoshi, Marina Selina, Max' F. J. R. Taylor, Brian S. Leander  PHYCOLOGICAL RESEARCH  55-  (2)  159  -175  2007/06  [Not refereed][Not invited]
     
    Samples of Sabulodinium undulatum Saunders et Dodge, the type species of the monospecific genus, were collected and characterized from Germany, Russia, Japan and Canada. This species has a laterally flattened, oval cell with a truncated apex and a dorsally pointing small episome. The dorsal margin of the hyposome has an undulating shape. A dorsal spine and/or antapical spine are sometimes present. The specimens of this heterotrophic species are 27.5-42.5 mu m long and 18.5-36.0 mu m wide, and have a theca with the plate arrangement apical pore complex (APC) 5' 1a 6' 5c 4s 6''' 1''''. The shape of the dorsal theca is variable. The species distribution seems to be restricted to northern temperate regions. Sabulodinium undulatum occurred in all sandy eulittoral areas throughout the year and was also present in sandy sublittoral and supralittoral (beach) samples. The species can tolerate a broad range of temperatures and salinities. Sabulodinium occurred from -2.0 to +24.3 degrees C and 4-35 salinity. It is likely that the observed variability in morphology and habitat reflect several varieties. We propose to establish three varieties within the species, namely S. undulatum var. undulatum, S. undulatum var. glabromarginatum, and S. undulatum var. monospinum. The systematic position of Sabulodinium is discussed in the context of comparative morphological and molecular phylogenetic data.
  • Aika Yamaguchi, Hiroshi Kawamura, Takeo Horiguchi  PHYCOLOGIA  46-  (3)  270  -276  2007/05  [Not refereed][Not invited]
     
    Protoperidinium bipes is a minute heterotrophic dinoflagellate with a very distinctive shape and a tabulation unique for the genus, resulting in its placement into the subgenus Minusculum. The small subunit rDNA and the large subunit rDNA sequences of this species were determined using the single-cell polymerase chain reaction technique and analyzed to estimate its phylogenetic position. The results of the phylogenetic analyses revealed that P. bipes positioned in the clade corresponding to the section Protoperidinium of the subgenus Protoperidinium. Although the species occasionally has been regarded to belong to a different genus, our molecular analysis clearly confirmed that it is a true member of the genus Protoperidinium. It was inferred from our analysis that the reduction of the number of precingular plates took place relatively recently during the course of evolution of Protoperidinium.
  • 山口愛果, 河村裕, 堀口健雄  藻類  55-  (1)  71  2007/03/10  [Not refereed][Not invited]
  • Richard N. Pienaar, Hiroto Sakai, Takeo Horiguchi  JOURNAL OF PLANT RESEARCH  120-  (2)  247  -258  2007/03  [Not refereed][Not invited]
     
    A new dinoflagellate Durinskia capensis Pienaar, Sakai et Horiguchi sp. nov. (Peridiniales, Dinophyceae), from tidal pools along the west coast of the Cape Peninsula, Republic of South Africa, is described. The dinoflagellate produces characteristic dense orange-red colored blooms in tidal pools. The organism is characterized by having a eukaryotic endosymbiotic alga. Ultrastructure study revealed the organism has a cellular construction similar to that of other diatom-harboring dinoflagellates. The cell is thecate and the plate formula is: Po, x, 4', 2a, 6", 5c, 4s, 5'", 2"", which is the same as that of Durinskia baltica, the type species of the genus Durinskia. D. capensis can, however, be distinguished from D. baltica by overall cell shape, the relative size of the 1a and 2a plates, the degree of cingular displacement, and the shape of the eyespot. Our molecular analysis based on SSU rDNA revealed that D. capensis is closely allied to D. baltica, thus supporting the assignment of this new species to this genus. This Durinskia clade takes a sister position to another diatom-harboring dinoflagellate clade, which includes Kryptoperidinium foliaceum and Galeidinium rugatum. Molecular analysis based on the rbcL gene sequence and ultrastructure study revealed that the endosymbiont of D. capensis is a diatom. The SSU rDNA gene trees indicated that four species with a diatom endosymbiont formed a clade, suggesting a single endosymbiotic origin.
  • 天羽美紀, 萩野恭子, 鈴木徳行, 堀口健雄  日本地球化学会年会講演要旨集  54th-  184  2007  [Not refereed][Not invited]
  • 三宅絵理, 澤辺智雄, 大内真理子, 堀口健雄, 松崎雅広, 伊村智  極域気水圏シンポジウムプログラム・講演要旨  29th-  132  2006/11  [Not refereed][Not invited]
  • Yoshihito Takano, Kyoko Hagino, Yuichiro Tanaka, Takeo Horiguchi, Hisatake Okada  MARINE MICROPALEONTOLOGY  60-  (2)  145  -156  2006/07  [Not refereed][Not invited]
     
    The phylogenetic position of an enigmatic calcareous nannoplankton Braarudosphaera bigelowii, whose taxonomic position has long been questioned, was investigated using molecular genetic methods. The SSU rDNA sequences of B. bigelowii were obtained using a single cell PCR technique independently from two single cells isolated from field samples. A BLAST search revealed that the SSU rDNA of B. bigelowii was most similar to those of the division Haptophyta. Subsequent phylogenetic analyses showed that B. bigelowii was included in a clade comprising members of the orders lsochrysidales and Coccolithales, the genus Cluysoculter and two unidentified haptophytes. Morphometric measurements of extant B. bigelowii populations were made to obtain precise information on their intraspecific size variation. The results showed that these populations could be subdivided into a small form (< 2.4 mu m), an intermediate form A (4.0-5.3 mu m), and an intermediate form B (5.3-7.2 mu m), although the borders of the latter two forms overlapped. The SSU rDNA sequences showed the presence of 10-bp substitutions plus six insertions/deletions between specimens of intermediate forms A and B. The levels of DNA variation between them suggested that these two forms are genetically distinct from each other. (c) 2006 Elsevier B.V. All rights reserved.
  • HORIGUCHI TAKEO, HARADA AI, OTSUKA SUSUMU  日本プランクトン学会報  53-  (1)  21-29  2006/02/25  [Not refereed][Not invited]
  • A. Yamaguchi, H. Kawamura, T. Horiguchi  Phycol. Res.  54-  (4)  317  -329  2006  [Not refereed][Not invited]
  • Takeo Horiguchi, Yoshihito Takano  Phycological Research  54-  (3)  193  -200  2006  [Not refereed][Not invited]
     
    To infer the phylogeny of both the host and the endosymbiont of Peridinium quinquecorne Abé, the small subunit (SSU) ribosomal DNA (rDNA) from the host and two genes of endosymbiont origin (plastid-encoded rbcL and nuclear-encoded SSU rDNA) were determined. The phylogenetic analysis of the host revealed that the marine dinoflagellate P. quinquecorne formed a clade with other diatom-harbouring dinoflagellates, including Kryptoperidinium foliaceum (Stein) Lindeman, Durinskia baltica (Levander) Carty et Cox and Galeidinium rugatum Tamura et Horiguchi, indicating a single endosymbiotic event for this lineage. Phylogenetic analyses of the endosymbiont in these organisms revealed that the endosymbiont of P. quinquecorne formed a clade with a centric diatom (SSU data indicated it to be closely related to Chaetoceros), whereas the endosymbionts of other three dinoflagellates formed a clade with a pennate diatom. The discrepancy between the host and the endosymbiont phylogenies suggests a secondary replacement of the endosymbiont from a pennate to a centric diatom in P. quinquecorne.
  • T. Horiguchi  Paleontl. Res.  10-  (4)  299  -309  2006  [Not refereed][Not invited]
  • M Tamura, S Shimada, T Horiguchi  JOURNAL OF PHYCOLOGY  41-  (3)  658  -671  2005/06  [Not refereed][Not invited]
     
    A new sand-dwelling dinoflagellate from Palau, Galeidinium rugatum Tamura et Horiguchi gen. et sp. nov., is described. The life cycle of this new alga consists of a dominant nonmotile phase and a brief motile phase. The motile cell transforms itself directly into the nonmotile cell after swimming for a short period, and cell division takes place in the nonmotile phase. The nonmotile cell possesses a dome-like cell covering, which is wrinkled and equipped with a transverse groove on the surface. The cell has 10-20 chloroplasts and a distinct eyespot. The motile cell is Gymnodinium-like in shape. The dinoflagellate possesses an endosymbiotic alga to which the chloroplasts belong and which is separated from the host (dinoflagellate) cytoplasm by a unit membrane. The endosymbiont cytoplasm also possesses its own eukaryotic nucleus and mitochondria. The eyespot is surrounded by triple membranes and is located in the host cytoplasm. Photosynthetic pigment analysis, using HPLC, revealed that G. rugatum possesses fucoxanthin as the principal accessory pigment instead of peridinin. The rbcL tree showed that G. rugatum is monophyletic with Durinskia baltica (Levander) Carty et Cox and Kryptoperidinium foliaceum (Stein) Lindemann and that this clade is closely related to the pennate diatom, Cylindrotheca sp. The endosymbiont of G. rugatum is therefore shown to be a diatom. Phylogenetic analysis based on small subunit rDNA sequences demonstrated that G. rugatum, D. baltica, and K. foliaceum, all of which are known to harbor an endosymbiont of diatom origin, are closely related.
  • 岩本理恵, 泉井直子, 小口慶子, 津田正史, 小林淳一, 勝又和人, 堀口健雄  マリンバイオテクノロジー学会大会講演要旨集  8th-  92  2005/05/28  [Not refereed][Not invited]
  • A molecular phylogenetic study of the heterotrophic genus, Protoperidinium (Peridiniales, Dinophyceae).
    Phycol. Res.  53: 38-50.-  2005  [Not refereed][Not invited]
  • 津田正史, 泉井直子, 新保和高, 佐藤昌昭, 福士江里, 川端潤, 勝又和人, 堀口健雄, 小林淳一  天然有機化合物討論会講演要旨集  46th-  653-658  2004/09/01  [Not refereed][Not invited]
  • S Sekida, T Horiguchi, K Okuda  EUROPEAN JOURNAL OF PHYCOLOGY  39-  (1)  105  -114  2004/02  [Not refereed][Not invited]
     
    The development of the pellicle and thecal plates of the dinoflagellate Scrippsiella hexapraecingula Horiguchi et Chihara was investigated with particular emphasis on cellulose synthesis. In young motile cells, incipient thecal plates appear as several groups of granular material within individual sites that are thought to be amphiesmal vesicles and develop into thin, sheet-like plates. These plates subsequently thicken with the deposition of amorphous material and cellulose microfibrils to form mature thecal plates. After ecdysis, non-motile cells form a pellicle consisting of three layers, L1-3. L1 is electron dense, while L2 and L3 are electron transparent. L1 and L2 are non-cellulosic, but L3 contains cellulose microfibrils. A new type of putative cellulose-synthesizing enzyme complex was found in non-motile cells. It consists of two rows of particles occurring on the plasmatic fracture face of the plasma membrane and begins to appear 0.5-1 h after ecdysis. The periodic acid-thiocarbohydrazide-silver proteinate test (PATAg) strongly stains the plasma membrane in both motile and non-motile cells throughout most of the life cycle of this species. The only time when it does not stain the plasma membrane is during an approximately 1-h period following ecdysis. During this period, the plasma membrane stains strongly with a silicotungstic acid-chromic acid mixture (STA-CA). STA-CA also stains the inner membranes of amphiesmal vesicles in both motile and non-motile cells. Thus, changes in the ability of PATAg and STA-CA to stain membranes during development suggest that the plasma membrane in non-motile cells is undergoing transformation after ecdysis.
  • First Record of Occurrence of an ellobiosid Thalassomyces marsupii Kane on a New Host of Hyperiid Amphipod in Japanese Waters.
    Plank. Biol. Ecol.  51: 110-112.-  2004  [Not refereed][Not invited]
  • Surface ultrastructure and molecular phylogenetics of four unarmoured heterotrophic dinoflagellates, including the type species of Gyrodinium (Dinophyceae).
    Phycol. Res.  52:106-117-  2004  [Not refereed][Not invited]
  • Phylogenetic studies in the genus Codium (Chlorophyta) from Japan.
    Jpn. J. Phycol. (Suppl.)  137-141.-  2004  [Not refereed][Not invited]
  • Ultrastructure and phylogeny of benthic dinoflagellates releasing Amphidinium-like swarmers.
    Jpn. J. Phycol. (Suppl.)  201-207-  2004  [Not refereed][Not invited]
     
    (2004).
  • M Tsuda, N Izui, K Shimbo, M Sato, E Fukushi, J Kawabata, K Katsumata, T Horiguchi, J Kobayash  JOURNAL OF ORGANIC CHEMISTRY  68-  (13)  5339  -5345  2003/06  [Not refereed][Not invited]
     
    A novel cytotoxic 16-membered macrodiolide, amphidinolide X (1), has been isolated from a marine dinoflagellate Amphidinium sp. (strain Y-42). The gross structure of 1 was elucidated on the basis of spectroscopic data including one-bond and long-range C-13-C-13 correlations. The relative and absolute stereochemistries were determined by combined analyses of NOESY data and H-1-H-1 and H-1-C-13 coupling constants of 1 and NMR data of the degradation products. Amphidinolide X (1) is the first macrodiolide consisting of polyketide-derived diacid and diol units from natural sources. The biosynthetic origins of I were investigated by means of feeding experiments with C-13-labeled acetates.
  • 有毒・有害プランクトンの生態 Prorocentrum micans。
    養殖  2002-  (5: 43.)  2003  [Not refereed][Not invited]
     
    (2003)
  • Intersex in the mysid Siriella japonicus Ii: the possibility it is caused by infestation with parasites.
    Journal of Plankton Biology and Ecology  50: 65-70-  2003  [Not refereed][Not invited]
     
    (2003)
  • Takeo Horiguchi, Mona Hoppenrath  Phycological Research  51-  (1)  61  -67  2003  [Not refereed][Not invited]
     
    A new, marine, sand-dwelling raphidophyte from Sylt, Germany, Haramonas viridis Horiguchi et Hoppenrath sp. nov. is described. This represents a second species in the previously monotypic genus Haramonas, which was originally described from a sand sample from a mangrove river mouth in tropical Australia, based on the type species, H. dimorpha. This new species from a cold temperate region: (i) possesses a tubular invagination in the posterior part of the cell (ii) produces copious amounts of mucilage in culture (iii) possesses both motile and non-motile stages in its life cycle and (iv) has overlapping discoidal chloroplasts, all of which are diagnostic features of the genus Haramonas. Therefore, it is indisputable that this species belongs to this genus. However, the species from Sylt differs from the type species of the genus in: (i) having a larger cell size (ii) possessing a larger number of chloroplasts and (iii) being greenish in color. The ultrastructural study revealed that the structure of the tubular invagination was the same as that of the type species.
  • Valérie Stiger, Takeo Horiguchi, Tadao Yoshida, Annette W. Coleman, Michio Masuda  Phycological Research  51-  (1)  1  -10  2003  [Not refereed][Not invited]
     
    Sequences from the ribosomal DNA internal transcribed spacer-2 (ITS-2) were compared among species of Sargassaceae including the genera Sargassum and Hizikia. Species of different subgenera and sections of Sargassum were used to assess the taxonomic relationships within the genus, especially the subdivisions of the subgenus Bactrophycus. Sequences were aligned in accordance with their common secondary structure. Phylogenetic trees were constructed using neighbor-joining, maximum likelihood and maximum parsimony methods with three species of Turbinaria as outgroups. The resulting phylogenetic trees showed that the genus Sargassum is divided into three clades corresponding to the subgenera Phyllotrichia, Sargassum and Bactrophycus. This last subgenus is further divided into four distinct groups: a Spongocarpus clade, a Teretia clade, a Hizikia clade, and a Halochloa/Repentia clade. The position of the section Phyllocystae, excluded from the subgenus Bactrophycus and included within the subgenus Sargassum is once again confirmed by the present study. Current results strongly support the assignation of Hizikia fusiformis to the genus Sargassum. Based on morphological differences and a distinct position in the molecular trees, Hizikia should be recognized as a section in the subgenus Bactrophycus so that Hizikia (Okamura) Yoshida, stat. nov. is proposed. A remarkably low divergence of ITS-2 sequences was observed for the species in the sections Repentia and Halochloa, suggesting very recent radiation of these species. The subgenus Sargassum is divided into three clades corresponding to the three known sections: Acanthocarpicae, Malacocarpicae and Zygocarpicae, previously recognized by the morphology of receptacles. The position of Sargassum duplicatum, S. carpophyllum, S. yendoi, S. piluliferum and S. patens within the subgenus Sargassum is discussed.
  • 福田伊佐央, 大木修一, 藤田利宏, 渡辺俊樹, 岩尾研二, 堀口健雄, 村山英未, 長沢寛道, 伊佐英信  マリンバイオテクノロジー学会大会講演要旨集  6th-  79  2002/05/25  [Not refereed][Not invited]
  • 堀口健雄  養殖  39-  (6)  43  2002/05/01  [Not refereed][Not invited]
  • 原慶明, 堀口健雄, 半沢直人, 石田健一郎, 横山亜紀子, 保科亮, 工藤創, 越智昭彦, 近野麻里  月刊海洋  19-26  2002/04/01  [Not refereed][Not invited]
  • パラオ海水湖における海産大型藻類の固有進化。
    月刊海洋  号外No.2919-26-  2002  [Not refereed][Not invited]
     
    (2002)
  • Isolation of Actin-Encoding cDNAs from Symbiotic Corals.
    DNA Res  9: 1-7-  2002  [Not refereed][Not invited]
     
    (2002)
  • Rejection of Sinkoraena and transfer of some species of Carpopeltis and Sinkoraena to Polyopes (Rhodophyta, Halymeniaceae).
    Phycologia  41: 619-635-  2002  [Not refereed][Not invited]
     
    (2002)
  • TSUDA MASASHI, KUBOTA TAKAAKI, SHIMBO KAZUTAKA, HORIGUCHI TAKEO, KATSUMATA KAZUHITO, KOBAYASHI JUN'ICHI  日本化学会講演予稿集  80th-  3  2001/09/07  [Not refereed][Not invited]
  • 堀口健雄  月刊地球  23-  (3)  186-190  2001/03/01  [Not refereed][Not invited]
  • 生命と地球の共進化(3) 繰り返された細胞内共生と藻類の起源
    月刊地球  23-  138  -190  2001  [Not refereed][Not invited]
  • Hong Wei Wang, Shigeo Kawaguchi, Takeo Horiguchi, Michio Masuda  Phycological Research  49-  (3)  251  -261  2001  [Not refereed][Not invited]
     
    A critical reassessment of the morphological features of two closely related red algal genera, Grateloupia C. Agardh and Prionitis J. Agardh (Halymeniaceae), shows that members of the two genera share very similar reproductive (including the Grateloupia-type auxiliary-cell ampullae) and vegetative characters. Diagnostic features hitherto used for distinguishing these two genera, the texture of blades (lubricous to leathery in Grateloupia vs cartilaginous in Prionitis) and the position of reproductive structures (scattered over the entire blade in Grateloupia vs confined to particular portions of the blade in Prionitis), are continuous across some 75 species of both genera, thus making it difficult to draw a clear-cut distinction between the two genera. In ribulose-1,5-bisphosphate carboxylase/oxygenase gene (rbcL) sequence analyses, the species of Grateloupia and Prionitis, including the two generitypes, constitute a large monophyletic clade in the Halymeniaceae. It is therefore proposed that Prionitis be included in the synonymy under Grateloupia and the appropriate combinations are proposed.
  • Phycol. Res.  49: 163-176-  2001  [Not refereed][Not invited]
  • Oodinium inlandicum sp. Nov. (Blastodiniales, Dinophyta), a new ectoparastitc dinoflagellate infectingh a chaetognath, Sagitta crassa.
    Plankton Biol. Ecol.  48: 85-95.-  2001  [Not refereed][Not invited]
  • T Horiguchi, J Yoshizawa-Ebata, T Nakayama  JOURNAL OF PHYCOLOGY  36-  (5)  960  -971  2000/10  [Not refereed][Not invited]
     
    A new genus and species of marine coccoid dinoflagellate from subtropical Japan, Halostylodinium arenarium Horiguchi et Yoshizawa-Ebata, gen, et sp. nov., is described, The dominant stage of the dinoflagellate is a nonmotile ovoidal to spheroidal cell with a distinct stalk, The stalk consists of an upper thick tubule, a lower thin tubule, and a discoidal holdfast The dinoflagellate possesses a yellowish-brown chloroplast with multiple lobes radiating from a central pyrenoid, It reproduces by the formation of two motile cells, which swim for a short period and then transform directly into the stalked nonmotile cell, The stalk is produced during transformation from the apical stalk complex present in the apex of the motile cell, The apical stalk complex consists of a double-folded apical pore plate and doughnut-shaped holdfast-building material. The ultrastructure of the apical stalk complex is compared with those of Bysmatrum arenicola and Stylodinium littorale. Halostylodinium arenarium possesses delicate thecal plates, and the thecal plate formula is Po, 5', 2a, 7", 7c, 6s, 5"', Ip, 2'''', A phylogenetic study based on the 18S ribosomal RNA gene did not show any clear affinities between this organism and any species included in the analysis.
  • 関田諭子, 堀口健雄, 奥田一雄  日本植物学会大会研究発表記録  64th-  182  2000/09/27  [Not refereed][Not invited]
  • 堀口健雄  日本植物学会大会研究発表記録  64th-  70  2000/09/27  [Not refereed][Not invited]
  • Reinstatement of Grateloupia catenata (Rhodophyta, Halymeniaceae) on the basis of morphology and rbcL sequences
    HW Wang, S Kawaguchi, T Horiguchi, M Masuda  PHYCOLOGIA  39-  (3)  228  -237  2000/05  [Not refereed][Not invited]
     
    Morphological observations and molecular analysis of a red alga, which has been known as Grateloupia filicina var. lomentaria. G. filicina var. porracea f. lomentaria, or Sinotubimorpha porracea (Cryptonemiales, Halymeniaceae) in the western Pacific, were made for field-collected and cultured plants. The auxiliary-cell ampullae lack tertiary filaments and are of the Grateloupia-type. Morphologically, this alga can be distinguished from G. filicina by (1) the hollow axis; (2) the numerous short proliferations with Lomentaria-like constrictions that densely cover the surface of erect axes in mature plants; and (3) a tendency for reproductive structures to be restricted to the proliferations. The presence of 4.2=4.6% (62-67 bp) nucleotide substitutions in the ribulose-1,5-bisphosphate carboxylase/oxygenase gene (rbcL) between G. filicina and the alga in question also strongly supports the differentiation of these two entities at the species level. The form of the proliferations distinguishes the alga in question from the West Indies G. porracea. Re-examination of type material of Grateloupia catenata Yendo, which has been placed into synonymy under Grateloupia filicina var. porracea f. lomentaria, revealed that our freshly collected specimens matched it, and therefore the Yendo name is reinstated. The topological position of Grateloupia catenata in rbcL trees does not support its separation from other Groteloupia species at the generic rank.
  • 堀口健雄  月刊海洋  23-28  2000/05/01  [Not refereed][Not invited]
  • 堀口健雄  月刊海洋  57-64  2000/05/01  [Not refereed][Not invited]
  • 海洋植物プランクトン(]G0002[)-その分類・生理・生態- 海洋植物プランクトンと他生物との関係-細胞内共生-
    月刊海洋号外  21-  163  -168  2000  [Not refereed][Not invited]
  • 海洋植物プランクトン(]G0002[)-その分類・生理・生態- 渦鞭毛藻類
    月刊海洋号外  21-  57  -64  2000  [Not refereed][Not invited]
  • 海洋植物プランクトン(]G0002[)-その分類・生理・生態- クリプト藻類
    月刊海洋号外  21-  23  -28  2000  [Not refereed][Not invited]
  • 原生生物の系統分類の現状
    日本プランクトン学会報  47-  (1)  18  -25  2000  [Not refereed][Not invited]
  • Satoshi Shimada, Takeo Horiguchi, Michio Masuda  Phycological Research  48-  (1)  37  -46  2000  [Not refereed][Not invited]
     
    Two new marine red algae, Gelidium tenuifolium sp. nov. and Gelidium koshikianum sp. nov. (Gelidiales, Gelidiaceae) are described from Japan. Gelidium tenuifolium with large-sized thalli (up to 30 cm tall) is distinguished from other species with such thalli by the production of wide, flattened and thin branches (up to 2 mm wide and 60-80 μm thick), the presence of an apical depression and simple determinate branches. Gelidium koshikianum with middle-sized thalli (5-8 cm tall) is distinguished from other species with such thalli by having wide axes (up to 2.5 mm wide) and short (2.0-3.2 mm), unbranched, second- and third-order branches issuing at short intervals (0.8-1.4 mm). In phylogenetic analyses of rbcL sequences, four Gelidium species that are chiefly distributed in Japan including G. tenuifolium were clustered together with 99% bootstrap value (Japanese Gelidium-complex clade). Gelidium linoides Kutzing came to the position of the sister group to G. tenuifolium with 99% bootstrap value. There were four substitutions (0.3% divergence) between G. linoides and G. tenuifolium sequences. Gelidium koshikianum and Gelidium allanii Chapman were clustered together with 100% bootstrap value and they came to the position of the sister group to the Japanese Gelidium-complex clade with 83% bootstrap value. There were six substitutions (0.4% divergence) between G. koshikianum and G. allanii sequences.
  • T. Yoshida, V. Stiger, T. Horiguchi  Phycological Research  48-  (3)  125  -131  2000  [Not refereed][Not invited]
     
    A new species, Sargassum boreale Yoshida et Horiguchi is described. It belongs to the subgenus Bactrophycus section Teretia, with cylindrical receptacles and is distinct from Sargassum confusum C. Agardh, S. pallidum (Turner) C. Agardh and Sargassum microceratium (Turner) C. Agardh in having a rather elongated stem with smooth surface and distantly issuing main branches, with narrow leaves. The distinction between S. boreale and these species is also revealed by a difference in internal transcribed spacer 2 (ITS-2) sequences. In addition to the base substitutions, the existence of a large gap in S. boreale distinguishes this species from others. Sargassum boreale is distributed around Hokkaido and Saghalien to 50°N latitude. A key to the species of section Teretia is provided.
  • Valérie Stiger, Takeo Horiguchi, Tadao Yoshida, Annette W. Coleman, Michio Masuda  Phycological Research  48-  (4)  251  -260  2000  [Not refereed][Not invited]
     
    Sequences of the end of the 5.8S gene and the internal transcribed spacer 2 (ITS-2) of nuclear ribosomal DNA have been determined for 19 species of the brown algal genus Sargassum (Sargassaceae), representing three subgenera and eight sections (sections are in parentheses): Phyllotrichia, Bactrophycus (Teretia, Spongocarpus, Halochloa and Repentia) and Sargassum (Acanthocarpicae, Malacocarpicae, Zygocarpicae) to assess the taxonomic position of the section Phyllocystae traditionally included within the Bactrophycus. The sequence of Myagropsis myagroides (Mertens ex Turner) Fensholt (Sargassaceae) was used as an outgroup. Sequences of ITS-2 were analyzed using neighbor-joining, parsimony and maximum likelihood methods. The results showed the existence of three clades in Sargassum, corresponding to the three subgenera. The subgenus Phyllotrichia is positioned near the outgroup. Two robust clades were obtained, one corresponding to the subgenus Bactrophycus and the other to the subgenus Sargassum. Sargassum mcclurei Setchell and Sargassum quinhonense Nguyen, the two Phyllocystae investigated, are close to species belonging to the section Zygocarpicae in the subgenus Sargassum. A transfer of the section Phyllocystae to the subgenus Sargassum is therefore proposed on the basis of molecular data (ITS-2) and morphological data (receptacles and basal leaf).
  • Journal of Phycology  36-  (1)  237  2000  [Not refereed][Not invited]
  • A brief review of recent classification system of "protists".
    Bulletin of Plankton Society of Japan  47-  (1)  18  -25  2000  [Not refereed][Not invited]
  • Phycological Research  48-  37  -46  2000  [Not refereed][Not invited]
  • The confirmation of the three Pterocladia(Gelidiales, Rhodophyta)species described by K. Okamura.
    Phycologia  39-  (1)  10  -18  2000  [Not refereed][Not invited]
  • Phylogeny of the order Scytosiphonales (Phaeophyceae) based on DNA sequences of rbcL, partial rbcS, and partial LSU nrDNA
    K Kogame, T Horiguchi, M Masuda  PHYCOLOGIA  38-  (6)  496  -502  1999/11  [Not refereed][Not invited]
     
    A molecular phylogenetic study of the order Scytosiphonales (Phaeophyceae) was carried out using DNA sequences of rbcL, partial r-bcS, and partial large subunit (LSU) nrDNA (domains D1 and D2) that were determined in 14 species. Ectocarpus siliculosus (Dillwyn) Lyngbye was adopted as an outgroup taxon. Phylogenetic trees inferred in maximum-parsimony and neighbor-joining analyses were almost identical to each other and showed two large clades. A monophyletic group distributed in warm-temperate to tropical regions includes Chnoospora implexa J. Agardh, Rosenvingea intricata (J. Agardh) Borgesen, Hydroclatrus clathratus (C. Agardh) Howe, and Colpomenia sinuosa (Mertens ex Roth) Derbes et Solier. The second clade includes Colpomenia bullosa (Saunders) Yamada, Colpomenia phaeodactyla Wynne et J. Norris, four species of Scytosiphon, and three species of Petalonia, which are mostly distributed in cold-temperate regions. Colpomenia peregrina (Sauvageau) Hamel showed an ambiguous position between the two large clades. Within the second large clade, a subclade of Petalonia fascia (O. F. Muller) Kuntze, P. binghamiae (J. Agardh) Vinogradova, and Scytosiphon tenellus Kogame and another subclade of Scytosiphon gracilis Kogame and Petalonia zosterifolia (Reinke) Kuntze were supported by high bootstrap values. These results seriously question autonomy of the Chnoosporaceae and monophyly of the genera Colpomenia, Scytosiphon, and Petalonia. Morphological characters of the prostrate sporophytes, such as thallus structure and presence or absence of plurilocular zoidangia, were congruent with the molecular phylogeny. These features are likely to be more important taxonomic criteria at the generic or family level in the Scytosiphonales than is the morphology of the erect gametophytes.
  • YOKOHAMA YASUTSUGU, HORIGUCHI TAKEO  生物の科学 遺伝  53-  (7)  53-58  1999/07/01  [Not refereed][Not invited]
  • 堀口健雄  日本海洋学会大会講演要旨集  1999-  294  1999/03/27  [Not refereed][Not invited]
  • Heterocapsa circularisquamaの分類とその問題点-形態分類
    日本プランクトン学会報  46-  (2)  164  -166  1999  [Not refereed][Not invited]
  • Direct evidence for cellulose microfibrils present in thecal plates of the dinoflagellate Scrippsiella hexapraecingula.
    HIKOBIA  13-  65  -69  1999  [Not refereed][Not invited]
  • An Improved Method for Fixing Dinoflagellate Non-motile Cells for Electron Microscopy.
    Memoirs of the Faculty of Science, Kochi University, Series D.(Biology)  20-  11  -15  1999  [Not refereed][Not invited]
  • Satoshi Shimada, Takeo Horiguchi, Michio Masuda  Phycologia  38-  (6)  528  -540  1999  [Not refereed][Not invited]
     
    Phylogenetic affinities of Acanthopeltis japonica Okamura and Yatabella hirsuta Okamura were determined from nucleotide: sequences of the nuclear-encoded small subunit rDNA (SSU), internal transcribed spacer 1 (ITS l), and plastid-encoded large subunit of the ribulose-1,5-bisphosphate carboxylase/oxgenase gene (rbcL). We have sequenced an additional nine species of Japanese gelidialean species. Although Acanthopeltis and Yatabella had been suggested to be derived from separate, lineages by researchers who emphasized the difference of growth pattern, they were recognized as a monophyletic group in the SSU, ITS1, and rbcL analyses. We have also demonstrated that Acanthopeltis and Yatabella possess a fundamentally similar type of growth pattern. The molecular data and morphological similarities indicate that Acanthopeltis and Yatabella are congeneric. The new combination, Acanthopeltis hirsuta (Okamura) Shimada, Horiguchi et Masuda, comb. nov., is proposed. Additional information on phylogenetic relationships within the Gelidiales was obtained. Our phylogenetic analyses of the Gelidiales using the above genes show three major clades, the Gelidiella clade that was the earliest diverging group within the order, a Pterocladia/Pterocladiella clade, and a large Gelidium-complex clade. The large Gelidium-complex clade is composed of the Ptilophora clade, Capreolia clade, and Gelidium-complex clades. In the rbcL and ITS 1 trees, the Gelidium-complex clade includes three subclades, one of which is recognized for the first time and includes Acanthopeltisi Yatabella, Onikusa japonica (Harvey) Akatsuka, and Gelidium vagum Okamura, all distributed in the western and eastern Pacific. The type of secondary rhizoidal attachment, the unicellular independent type, peg type, and brush type, is consistent with the respective three major clades of the Gelidiales, suggesting that this morphological character reflects the phylogeny of this order.
  • On Heterocapsa circularisquama - it's morpho-taxonomic problems.
    Bulletin of Plankton Society of Japan  46-  (2)  164  -166  1999  [Not refereed][Not invited]
  • Takeo Horiguchi, Hiroshi Kawai, Mamoru Kubota, Tetsuo Takahashi, Masakatsu Watanabe  Phycological Research  47-  (2)  101  -107  1999  [Not refereed][Not invited]
     
    Great structural variety is seen in the eyespot of dinoflagellates, a structure involved in phototaxis. Although there are several works on the phototactic responses in some species of dinoflagellates, none of the dinoflagellates used in these studies possessed an eyespot and, therefore, we have no knowledge of the relationship between eyespot type and phototactic response. In this study, we determined wavelength dependency curves for phototaxis in four marine dinoflagellates that possess a different type of either eyespot or chloroplast. These include: (i) a dinoflagellate possessing a peridinin-containing chloroplast with an eyespot (Scrippsiella hexapraecingula Horiguchi et Chihara) (ii) a dinoflagellate containing a diatom endosymbiont and with the type B eyespot sensu Dodge (1984 (Peridinium foliaceum (Stein) Biecheler) (iii) a dinoflagellate with peridinin-containing chloroplasts, but lacking an eyespot (Alexandrium hiranoi Kita et Fukuyo) and (iv) a dinoflagellate with fucoxanthin, 19'-hexanoyloxyfucoxanthin and 19'-butanoyloxyfucoxanthin, but lacking an eyespot (Gymnodinium mikimotoi Miyabe et Kominami ex Oda). Regardless of the eyespot or the chloroplast type, all four dinoflagellates showed similar wavelength dependency curves for phototaxis, with sensitivity between 380 and 520 nm, the highest peak at approximately 440 or 460 nm and smaller peaks or shoulders at 400-420 nm and 480-500 nm. Substantial peaks have also been noted in the ultraviolet range (260-280 nm). The ultrastructural study of the eyespot of Scrippsiella hexapraecingula revealed that the eyespot consists of two layers of lipid globules and probably acts as a quarter-wave stack antenna.
  • 四ツ倉典滋, 伝法隆, 本村泰三, 堀口健雄, 市村輝宜  日本水産学会大会講演要旨集  1998-  70  1998/09  [Not refereed][Not invited]
  • The phylogenetic affinities of Myagropsis myagroides (Fucales, Phaeophyceae) as determined from 18S rDNA sequences
    T Horiguchi, T Yoshida  PHYCOLOGIA  37-  (4)  237  -245  1998/07  [Not refereed][Not invited]
     
    Phylogenetic affinities of the fucalean brown alga, Myagropsis myagroides (Mertens ex Turner) Fensholt (Fucales, Phaeophyceae), were determined from 18S rDNA sequences. We have sequenced 10 species of fucalean algae collected from various parts of Japan: Fucus distichus ssp. evanescens (C. Agardh) Powell, Pelvetia babingtonii (Harvey) De Toni (Fucaceae), Cystoseira hakodatensis (Yendo) Fensholt, Coccophora langsdorfii (Turner) Greville, Myagropsis myagroides (Cys toseiraceae), Sargassum horneri (Turner) C. Agardh, S. confusum C. Agardh, S. macrocarpum C. Agardh, Sargassum sp., and Hizikia fusiformis (Harvey) Okamura (Sargassaceae). Phylogenetic trees constructed using maximum likelihood, maximum parsimony, and distance matrix methods resulted in similar topology. Although currently Myagropsis is regarded as a member of the Cystoseiraceae, our results revealed that Myagropsis is more closely related to members of the Sargassaceae. This implies that the morphological character (mode of branching) used to discriminate the Cystoseiraceae and the Sargassaceae is not phylogenetically meaningful. Monophyly of the Cystoseiraceae and the Sargassaceae was strongly supported by both bootstrap analyses and likelihood ratio test. The close affinity of these two families was also demonstrated by the smaller number of nucleotide differences compared to those between other families. This result is consistent with previous molecular work that used a different set of species mainly collected in Australian waters.
  • YOTSUKURA NORISHIGE, DENPO TAKASHI, MOTOMURA TAIZO, HORIGUCHI TAKEO, ICHIMURA TERUYOSHI  日本水産学会大会講演要旨集  1998-  31  1998/04  [Not refereed][Not invited]
  • Takeo Horiguchi, Tadao Yoshida, Manabu Nagao, Isamu Wakana, Yasutugu Yokohama  Phycological Research  46-  (4)  253  -261  1998  [Not refereed][Not invited]
     
    This study compares the ultrastructure of the inner, dark-habituated cells of the green 'Cladophora-ball', or Marimo, to that of similar cells at the surface. Cells not exposed to light possess fewer, but larger and more irregular, chloroplasts than do the outer cells. Unexposed chloroplasts have a pyrenoid matrix lacking starch sheaths and containing unusually thick granal stacks. Despite prolonged exposure to darkness, the chloroplasts contain small starch grains. After exposure to light, such chloroplasts divide, become smaller and take on the appearance of those in the outer layer cells. Within 48 h, all of the chloroplasts develop substantial starch grains and the pyrenoids are surrounded by starch sheaths. This response is consistent with previous reports of the recovery of photosynthetic activity in inner cells exposed to light.
  • Takeo Horiguchi, Junko Yoshizawa-Ebata  Phycological Research  46-  (4)  205  -211  1998  [Not refereed][Not invited]
     
    The ultrastructure of Stylodinium littorale Horiguchi et Chihara, a marine, sand-dwelling coccoid dinoflagellate, was investigated with special emphasis on its stalk and the apical stalk complex. The dinoflagellate alternates between non-motile and motile cells in its life cycle. The non-motile cell possesses a long and distinct stalk. The stalk, consisting of a main cylindrical part and a holdfast, is firmly attached to a thecal plate (the apical pore plate). A part of its proximal portion is hollow and V-shaped in section. The V-shaped hollow space is underlain by a projection from the apical pore plate. An apical stalk complex is present in the motile cells and consists of a large apical pore plate and mucilaginous material. The apical pore plate is depressed into the cell, but has a narrow central tubular projection. The mucilaginous stalk-building material is stored between this plate and the outer plate membrane. The tubular projection of the apical pore plate corresponds to the apical pore of other dinoflagellates and its lumen is filled with electron-dense material. The structure of the apical stalk complex is compared with the homologous structure in Bysmatrum arenicola, the only other example of an apical stalk complex that has been investigated. A general ultrastructural survey revealed that S. littorale possesses a typical dinoflagellate cellular structure.
  • HORIGUCHI TAKEO  日本海洋学会大会講演要旨集  1998-  248  1998  [Not refereed][Not invited]
  • 四ツ倉典滋, 伝法隆, 本村泰三, 堀口健雄, 市村輝宜  化学工学会関東支部大会研究発表講演要旨集  1998-  155  1998  [Not refereed][Not invited]
  • Heterocapsa arctica sp nov (Peridiniales, Dinophyceae), a new marine dinoflagellate from the arctic
    T. Horiguchi  PHYCOLOGIA  36-  (6)  488  -491  1997/11  [Not refereed][Not invited]
     
    ]A culture strain labeled CCMP445: Heterocapsa sp. deposited in the Culture Collection of Marine Plankton, Bigelow, ME, was studied by means of light and electron microscopy and is described as a new species, Heterocapsa arctica Horiguchi sp. nov. The cells are elongated, consisting of a large epitheca and a small hypotheca. Each cell possesses a parietal chloroplast with a spherical pyrenoid, the matrix of which is penetrated by many tubular extensions of cytoplasm. Heterocapsa arctica possesses triangular scales typical of the genus. The thecal plate arrangement is Po, cp, 5 ', 3a, 7 '', 6c, 5s, 5 ''', 2 '''', which is identical to that of most of the members of the genus Heterocapsa. However, H. arctica is readily distinguished from all other described species of Heterocapsa by its unique, elongated cell shape.
  • HORIGUCHI TAKEO  月刊地球  19-  (5)  290-295  1997/05  [Not refereed][Not invited]
  • 藻類の系統と進化
    月刊地球  19-  (5)  290  -295  1997  [Not refereed][Not invited]
  • Takeo Horiguchi, Fumiyasu Kubo  Phycological Research  45-  (2)  65  -69  1997  [Not refereed][Not invited]
     
    A new, sand-dwelling, armored dinoflagellate, Roscoffia minor sp. nov., is described from Ishikari beach, Hokkaido, Japan. The dinoflagellate has been collected from sand samples taken both near the water's edge and further upshore (25 m from the water's edge at a depth of 1 m), indicating that it is a true sand-dwelling species. Roscoffia minor is heterotrophic and lacks both a chloroplast and an eyespot. The cell consists of a flattened cap-shaped epitheca and a large hemispheroidal hypotheca, and it is quite different from cells of the typical armored dinoflagellates. The thecal plate formula is: Po, 3′, la, 5″, 3c, 3s, 5‴, 1″″. Its distinct cell shape and the thecal plate arrangement indicate affinity to the monotypic genus Roscoffia. Roscoffia minor is distinguished from Roscoffia capitata, the type species, by its smaller size and the possession of a finger-like apical projection. The thecal arrangement of the epitheca is similar to those of the members of the family Podolampaceae, while the hypothecal arrangement is the same as that of members of the subfamily Diplopsalioideae (family Congruentidiaceae). The organism seems to be positioned somewhere intermediate between these two families, but the family to which this dinoflagellate should be affiliated could not be determined.
  • SEKITA SATOKO, HORIGUCHI TAKEO, MINE ICHIRO, OKUDA KAZUO  日本植物学会大会研究発表記録  61st-  310  1997  [Not refereed][Not invited]
  • HORIGUCHI TAKEO  生物の科学 遺伝  50-  (7)  73-78  1996/07  [Not refereed][Not invited]
  • Haramonas dimorpha gen-et sp. nov. (Raphidophyceae), a new marine raphidophyte from Australian mangrove
    Phycological Research  44-  (3)  143  -150  1996  [Not refereed][Not invited]
  • Endosymbioses in dinoflagellates-Their diversity and evolutionary implications.
    Proceedings of the Japanese Society of Plant Taxonomists  11-  (2)  59  -74  1996  [Not refereed][Not invited]
  • HORIGUCHI TAKEO, YOSHIDA TADAO  日本植物学会大会研究発表記録  60th-  229  1996  [Not refereed][Not invited]
  • Takeo Horiguchi  Phycological Research  43-  (2)  93  -99  1995  [Not refereed][Not invited]
     
    A new sand‐dwelling dinoflagellate is described from Sesoko Beach, Okinawa Island, subtropical Japan and its micromorphology is studied by means of light and electron microscopy. The cell consists of a small epitheca and a large hypothecs superficially resembling members of the unarmored genus Amphidinium. The cell is dorso‐ventrally flattened and possesses a single chloroplast with a large conspicuous pyrenoid. Transmission electron microscopy revealed that the dinoflagellate possesses typical dinoflagellate cellular organization. Scanning electron microscopy demonstrated that the organism is thecate and the thecal plate arrangement is Po, 4′, 1a, 7″, 5c, 4s, 6″′, 2″″. Most of the characteristics suggest gonyaulacalean affinity of the new species. These are the presence of ventral pore, lack of canal plate, direct contact between the sulcal anterior plate and the flagellar pore, possession of six postcingular plates and asymmetrical arrangement of the antapical plates. Affinity to existing families of the order Gonyaulacales has not been determined. Based on the unique cell shape, thecal plate arrangement and the presence of ventral pore, a new genus, Amphidiniella, is established for this organism and the species is named A. sedentaria Horiguchi gen. et sp. nov. Copyright © 1995, Wiley Blackwell. All rights reserved
  • Heterocapsa circularisquama sp nov. (Peridiniales, Dinophyceae) : a new marine dinoflagellate causing mass mortality of bivalves in Japan.
    Phycological Research  43-  (3)  126  -136  1995  [Not refereed][Not invited]
  • HORIGUCHI TAKEO  日本植物学会大会研究発表記録  59th-  91  1995  [Not refereed][Not invited]
  • ULTRASTRUCTURE OF A NEW MARINE SAND-DWELLING DINOFLAGELLATE, GYMNODINIUM-QUADRILOBATUM SP-NOV (DINOPHYCEAE) WITH SPECIAL REFERENCE TO ITS ENDOSYMBIOTIC ALGA
    T HORIGUCHI, RN PIENAAR  EUROPEAN JOURNAL OF PHYCOLOGY  29-  (4)  237  -245  1994/11  [Not refereed][Not invited]
     
    A new sand-dwelling dinoflagellate, Gymnosodium quadrilobatum sp. nov., is described from the south coast of Natal, South Africa. The organism contains 20-30 chloroplasts, which are peripherally arranged, and a conspicuous eyespot. The motile cell is directly transformed into a non-motile cell and cell division is restricted to the non-motile phase. The motile cell has a typical gymnodinioid organisation, while the non-motile cell possesses a thick cell wall and develops the characteristic cell shape, which is reminiscent of a four-leaved clover. The chloroplasts of G. quadrilobatum belong to an endosymbiotic alga the cytoplasm of which is separated from the host (dinoflagellate) cytoplasm by a single unit membrane. Other organelles contained in the endosymbiont cytoplasm are the nucleus, ribosomes and mitochondria. The endosymbiont is thought to be a chromophyte alga. The eyespot is bounded by a triple membrane and is situated in the host cytoplasm. On the basis of the similarities in the ultrastructure of G. quadrilobatum with those of four thecate dinoflagellates, viz. Peridinium balticum, P. foliaceum, P. quinquecorne and Peridinium sp., which are known to possess a similar endosymbiont, possible phylogenetic affinities between G. quadrilobatum and four thecate dinoflagellates are discussed.
  • On the identity of a red-tide dinoflagellate in Maribago Bay, Philippines.
    Bulletin of Plankton Society of Japan  41-  166  -169  1994  [Not refereed][Not invited]
  • ULTRASTRUCTURE AND ONTOGENY OF A NEW-TYPE OF EYESPOT IN DINOFLAGELLATES
    T HORIGUCHI, RN PIENAAR  PROTOPLASMA  179-  (3-4)  142  -150  1994  [Not refereed][Not invited]
     
    Ultrastructure and ontogeny of a new type of eyespot in dinoflagellates is described. A marine tidal pool Gymnodinium natalense is found to possess a highly organized eyespot whose structure is unique among dinoflagellates. The eyespot is rectangular in ventral view, C-shaped in apical view, and is located posterior to the sulcus. The eyespot is independent of the chloroplast and consists of several (typically six) layers of hemi-cylindrical walls which are concentrically arranged with narrow spacing between them. Each hemicylindrical wall is enclosed by a single unit membrane and is composed of many regularly arranged rectangular crystalline bricks. These crystalline bricks are produced in small vesicles which are formed in the invaginations of the chloroplast. The vesicles containing newly formed crystalline bricks are then transported to the sulcal area to assemble the eyespot. The crystalline bricks are arranged in a neat row within the vesicle termed ''eyespot forming vesicle'' (EFV), which is located near the sulcus. The hemi-cylindrical wall is constructed within the EFV. Based on the structure of the eyespot, viz. consisting of concentric multi-layered walls, the eyespot is thought to act as a quarter-wave stack antenna.
  • A taxonomic survey of freshwater dinoflagellates of Nagano Prefecture, Japan.
    Japanese Journal of Phycology  42-  29  -42  1994  [Not refereed][Not invited]
  • Gymnodinium natalense sp. nov. (Dinophyceae), a new tide pool dinoflagellate from South Africa.
    Japanese journal of Phxcology  42-  21  -28  1994  [Not refereed][Not invited]
  • 吉沢順子, 堀口健雄  日本植物学会大会研究発表記録  58th-  106  1994  [Not refereed][Not invited]
  • HORIGUCHI TAKEO, SENZAKI SATOSHI, NAKAMURA MIHO, NETSU ITARU, MIYAZAWA KYOICHI, WATANABE TETSUHIRO  志賀自然教育研究施設研究業績  (29)  11-17  1992/03  [Not refereed][Not invited]
  • Amphidinium latum Lebour(Dinophyceae), a sand-dwelling dinoflagellate feeding on cryptomonads.
    Japanese Journal of phycology  40,353-363-  1992  [Not refereed][Not invited]
  • HORIGUCHI TAKEO  生物の科学 遺伝  45-  (5)  33-38  1991/05  [Not refereed][Not invited]
  • HORIGUCHI TAKEO, KAJITA MANABU, TANIGUCHI KAZUTO, MAEBA NAMI, KUBO FUMIYASU, SUZUKI AKIRA  志賀自然教育研究施設研究業績  (28)  13-19  1991/03  [Not refereed][Not invited]
  • Ultrastructure of a marine dinoflagellate, Peridinium quinquecorne Abe(Peridiniales)from South Africa with particular reference to its chrysophyte endosymbiont.
    Botanica Marina  34,123-131-  1991  [Not refereed][Not invited]
  • HORIGUCHI TAKEO, KITAHARA MIZUKI, TANAKA AKINORI  志賀自然教育研究施設研究業績  (27)  1-7  1990/03/25  [Not refereed][Not invited]
  • IRIKA YOSHIHIKO, HORIGUCHI TAKEO, MASUO EMIKO  藻類  37-  (4)  291-294  1989/12  [Not refereed][Not invited]
  • HORIGUCHI TAKEO  好塩微生物研究会講演要旨集  26th-  7-9  1989/12  [Not refereed][Not invited]
  • A redescription of the tidal pool dinoflagellate Peridinium gregarium based on re-examination of the type material.
    British Phycological Journal  23,33-39-  1988  [Not refereed][Not invited]
  • Ultrastructure of a new sand-dwelling dinoflagellate, Surippsiella arenicola sp. nov.
    Journal of Phycology  24,426-438-  1988  [Not refereed][Not invited]
  • Spiniferodinium galeiforme, a new genus and species of benthic dinoflagellates(Phytodiniales, Pyrrhophyta)from Japan.
    Phycologia  26,478-487-  1987  [Not refereed][Not invited]

Awards & Honors

  • 2016/11 International Phycological Society The Tyge Christensen Prize
     
    受賞者: HORIGUCHI Takeo
  • 2015/08 Phycological Society of America Gerald W. Prescott Award
     
    受賞者: HORIGUCHI Takeo
  • 2009 International Phycological Society The Tyge Christensen Award
     
    受賞者: HORIGUCHI Takeo
  • 2002 日本藻類学会論文賞

Research Grants & Projects

  • 藻類の微細構造、分子系統、分類
  • Ultrastructure, molecular phylogeny and taxonomy of algae and protists

Educational Activities

Teaching Experience

  • Inter-Graduate School Classes(General Subject):Natural and Applied Sciences
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : 地球生命史, 生物進化, 地球環境変化, 気候変動, 生物大量絶滅, 生物多様性, 古生物科学, 地質年代
  • Biodiversity
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 理学院
    キーワード : 生物多様性,進化,絶滅,種分化,動物,植物,統計モデリング
  • Special Lecture on Natural History Science III
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 理学院
    キーワード : 植物プランクトン,有害藻類,基礎生産,環境変動
  • Taxonomy
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 理学院
    キーワード : 植物分類、国際藻類・菌類・植物命名規約、植物学ラテン語、学名、命名法
  • Advanced Biodiversity Study II
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 理学院
    キーワード : 藻類,生物多様性,進化,細胞共生,細胞進化,微細構造,生活環,地球史と生物
  • Methods in Biodiversity Studies
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 理学院
    キーワード : 生物多様性,分類,系統,古生物,進化発生学,動物,植物,海藻,原生生物,系統地理学
  • Biodiversity Studies I
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 分類学、系統学、生態学、種分化学、原核生物、菌類
  • Laboratory Course in Systematic Botany
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 光合成生物,陸上植物,藻類,顕微鏡法,培養法
  • Laboratory Course in Marine Biology II
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 緑藻,褐藻,紅藻,海藻,植物プランクトン,生態,採集,標本作製
  • Biodiversity Studies II
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 藻類,陸上植物,無脊椎動物,脊椎動物,分類,系統,進化
  • Biology II
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 生物の多様性,系統,進化,生物の形態,生命活動の多様性
  • Systematics and Taxonomy II
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 光合成生物,植物,藻類,共生説,分類、系統
  • Readings of Scientific Literature
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 生物学,科学論文,英文読解,英作文,ヒアリング,プレゼンテーション

Campus Position History

  • 2015年4月1日 
    2017年3月31日 
    教育研究評議会評議員
  • 2015年4月1日 
    2017年3月31日 
    大学院理学研究院副研究院長
  • 2017年4月1日 
    2019年3月31日 
    教育研究評議会評議員
  • 2017年4月1日 
    2019年3月31日 
    大学院理学研究院副研究院長
  • 2019年4月1日 
    2021年3月31日 
    教育研究評議会評議員
  • 2019年4月1日 
    2021年3月31日 
    大学院理学研究院長
  • 2019年4月1日 
    2021年3月31日 
    理学部長

Position History

  • 2015年4月1日 
    2017年3月31日 
    教育研究評議会評議員
  • 2015年4月1日 
    2017年3月31日 
    大学院理学研究院副研究院長
  • 2017年4月1日 
    2019年3月31日 
    教育研究評議会評議員
  • 2017年4月1日 
    2019年3月31日 
    大学院理学研究院副研究院長
  • 2019年4月1日 
    2021年3月31日 
    教育研究評議会評議員
  • 2019年4月1日 
    2021年3月31日 
    大学院理学研究院長
  • 2019年4月1日 
    2021年3月31日 
    理学部長


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