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研究者情報

マスター

アカウント（マスター）

  • 氏名

    小亀　一弘(コガメ　カズヒロ), コガメ　カズヒロ

所属（マスター）

  • 理学研究院　生物科学部門　多様性生物学分野

所属（マスター）

  • 理学研究院　生物科学部門　多様性生物学分野

独自項目

syllabus

  • 2021, 分類学概論, Taxonomy, 修士課程, 理学院, 国際動物命名規約，国際藻類・菌類・植物命名規約、植物学ラテン語、学名、命名法,　分類学
  • 2021, 多様性生物学基礎論, Fundamental Course in Biological Diversity, 修士課程, 環境科学院, 生物多様性、遺伝的多様性、陸上植物、土壌微生物、藻類、哺乳類、鳥類、魚類、昆虫、陸水生物、海洋動物 Biodiversity, genetic variation, terrestrial plants, soil microorganisms, algae, mammals, birds, fishes, insects, freshwater organisms, marine animals
  • 2021, 大学院共通授業科目（一般科目）：自然科学・応用科学, Inter-Graduate School Classes(General Subject):Natural and Applied Sciences, 修士課程, 大学院共通科目, 生物多様性、遺伝的多様性、陸上植物、土壌微生物、藻類、哺乳類、鳥類、魚類、昆虫、陸水生物、海洋動物 Biodiversity, genetic variation, terrestrial plants, soil microorganisms, algae, mammals, birds, fishes, insects, freshwater organisms, marine animals
  • 2021, 多様性生物学特論Ⅱ, Advanced Biodiversity Study II, 修士課程, 理学院, 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
  • 2021, 多様性生物学研究法, Methods in Biodiversity Studies, 修士課程, 理学院, 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
  • 2021, 生物多様性概論, Introduction to Biological Diversity, 学士課程, 理学部, 現代生物科学，21世紀に生物科学が解決しなければならない課題，生物の多様性，系統，進化，生物の形態，生命活動の多様性
  • 2021, 科学・技術の世界（1単位）, The World of Science and Technology, 学士課程, 全学教育, 現代生物科学，21世紀に生物科学が解決しなければならない課題，生体高分子，細胞の構造と機能，エネルギー代謝，細胞の成長と分裂，遺伝現象と遺伝子発現制御
  • 2021, 基礎生物学実習, Laboratory Course in Basic Biology, 学士課程, 理学部, 脊椎動物の形態、染色体、細胞、植物、昆虫、土壌動物、ショウジョウバエ、唾腺染色体、博物館標本
  • 2021, 生物学Ⅱ, Biology II, 学士課程, 全学教育, 生物の多様性，系統，進化，生物の形態，生命活動の多様性
  • 2021, 生物学特別講義Ⅰ, Special Lecture in Biology I, 学士課程, 理学部, 自然史、海藻学、アオサ藻、褐藻、紅藻、ハーバリウム、標本レスキュー、常設展、企画展
  • 2021, ISP生物科学実習Ⅰ・a, ISP Biological Laboratory Course I･a, 学士課程, 理学部
  • 2021, ISP生物科学実習Ⅰ・b, ISP Biological Laboratory Course I･b, 学士課程, 理学部
  • 2021, 植物系統分類学実習, Laboratory Course in Systematic Botany, 学士課程, 理学部, 光合成生物，陸上植物，藻類，顕微鏡法
  • 2021, 臨海実習Ⅱ, Laboratory Course in Marine Biology II, 学士課程, 理学部, 緑藻，褐藻，紅藻，海藻，植物プランクトン，生態，採集，標本作製
  • 2021, 臨海実習Ⅱ, Laboratory Course in Marine Biology II, 学士課程, 理学部
  • 2021, 多様性生物学Ⅱ, Biodiversity Studies II, 学士課程, 理学部, 藻類，陸上植物，無脊椎動物，脊椎動物，分類，系統，進化
  • 2021, 系統分類学Ⅱ, Systematics and Taxonomy II, 学士課程, 理学部, 光合成生物，植物，藻類，共生説，分類、系統
  • 2021, 系統分類学Ⅱ, Systematics and Taxonomy II, 学士課程, 理学部
  • 2021, 基礎形態学実習, Laboratory Exercise in Basic Morphology, 学士課程, 理学部, 組織、器官、細胞、細胞形態、 プレパラート、顕微鏡、パラフィン切片、幹細胞，細胞多能性，細胞全能性，細胞分化
  • 2021, 基礎形態学実習, Laboratory Exercise in Basic Morphology, 学士課程, 理学部

researchmap

プロフィール情報

学位

  • 博士（理学）（北海道大学）

プロフィール情報

  • 姓

    小亀, コガメ

  • 名

    一弘, カズヒロ

  • ID各種

    200901016758644482

業績リスト

研究キーワード

  • 分子系統   海藻   藻類   分類   系統   

研究分野

  • ライフサイエンス / 多様性生物学、分類学

委員歴

  • 2021年01月 - 2022年12月   日本藻類学会   会長
  • 2017年01月 - 2019年12月   日本藻類学会   Editor-in-Chief of Phycological Research
  • 2016年01月 - 2016年12月   日本藻類学会   Associate Editor of Phycological Research
  • 2009年01月 - 2012年12月   日本藻類学会   庶務幹事
  • 2004年01月 - 2006年12月   日本藻類学会   Associate Editor of Phycological Research
  • 2000年01月 - 2002年12月   International Phycological Society   Member of Executive Council
  • 1995年01月 - 1996年12月   日本藻類学会   会計幹事

受賞

  • 2019年 International Phycological Society Tyge Christensen Prize 2018
     Concordance between DNA-based species boundaries and reproductive isolating barriers in the Scytosiphon loentaria species complex (Ectocarpales, Phaeophyceae). Phycologia 57: 232–242. 
    受賞者: Masakazu Hoshino, Shozo Ishikawa and Kazuhiro Kogame
  • 1993年03月 日本藻類学会 日本藻類学会賞
     
    受賞者: 小亀一弘;川井浩史

論文

  • Wilfred John E. Santiañez, John Michael L. Lastimoso, Masakazu Hoshino, Brix Nester Q. Villafuerte, Kazuhiro Kogame, Gavino C. Trono
    Cryptogamie, Algologie 44 7 2023年10月18日
  • Maria Emilia Croce, Masakazu Hoshino, Maria Cecilia Gauna, Elisa R Parodi, Kazuhiro Kogame
    Journal of phycology 59 2 383 - 401 2023年04月 
    Scytosiphon is a common intertidal genus widely distributed on temperate coasts worldwide. Recently, eight species have been delimited with molecular tools. Although S. lomentaria is the only species that predominates in the macroalgal literature of the Southwestern Atlantic Ocean (SwAO), unpublished molecular data obtained for a population study of S. lomentaria revealed hidden species diversity of Scytosiphon among the individuals collected from four localities at the SwAO. The aim of this study was to revise the identity and phylogenetic relationships of Scytosiphon from temperate coasts of the SwAO using DNA data. Thalli were collected from the Argentinean coast between 39° S and 43° S, from which cox1 and rbcL gene sequences were obtained. Phylogenies and haplotype networks were inferred and morphology of gametophytes was studied. Four species were recognized, S. lomentaria, S. promiscuus, S. shibazakiorum, and one species that belongs to a complex of species known as "Scytosiphon Atlantic complex." This complex was known to occur only in the North Atlantic, however, the results found in this study revealed that it has an extended distribution range that includes the southern hemisphere, where its populations have high genetic diversity and unique haplotypes. The morphological differences among the four species were subtle; denoting that previous Scytosiphon records from the SwAO attributed to the renowned S. lomentaria could represent different species. In addition, sex ratio and genome-wide single nucleotide polymorphisms (SNPs) analyses were done for populations of S. promiscuus presumably introduced to the SwAO, and the results indicated that they included female-dominant parthenogenetic populations, which were probably introduced from Japan.
  • Rachael M Wade, Paul W Gabrielson, Katharine R Hind, Jade Shivak, Jeffery R Hughey, Sou Ohtsu, Masasuke Baba, Kazuhiro Kogame, Sandra C Lindstrom, Kathy Ann Miller, Soren R Schipper, Patrick T Martone
    Journal of phycology 59 1 221 - 235 2023年02月 
    Partial rbcL sequences from type specimens of three of the earliest described Corallina species showed that C. arbuscula (type locality: Unalaska Island, Alaska, USA) and C. pilulifera (type locality: Okhotsk Sea, Russia) are synonymous, with C. pilulifera as the taxonomically accepted name and that C. vancouveriensis (type locality: Botanical Beach, Vancouver Island, Canada) is a distinct species. To identify molecular species limits and clarify descriptions and distributions of C. pilulifera and C. vancouveriensis, we sequenced and analyzed portions of one mitochondrial and two plastid genes from historical and recent collections. The single-gene phylogenetic reconstructions support the recognition of both species as distinct, as well as two additional species, C. hakodatensis sp. nov. and C. parva sp. nov., which are sister to, and often morphologically indistinguishable from C. pilulifera and C. vancouveriensis, respectively. DNA sequence data currently illustrate that C. pilulifera is found in the cold northern Pacific waters from the Okhotsk Sea of Russia to Hokkaido, Japan, eastward across the Aleutian Islands to Knoll Head, Alaska, and as far south as Nanaimo, British Columbia. Corallina vancouveriensis is distributed as far west as Attu Island in the Aleutian Islands to Sitka, Alaska, and southeasterly at numerous sites from British Columbia to the north of Point Conception, California, USA. The cryptic species C. hakodatensis and C. parva occur sympatrically with their sister species but with narrower ranges. The complex phylogenetic relationships shown by the single gene trees recommend Corallina as a model genus to explore coralline algal biogeography, evolution, and patterns of speciation.
  • Michael Jacob C. Dy, Masakazu Hoshino, Tsuyoshi Abe, Norishige Yotsukura, Nina Klochkova, Kyung Min Lee, Sung Min Boo, Kazuhiro Kogame
    Phycological Research 71 2 81 - 89 2022年12月22日 
    SUMMARY Colpomenia borea sp. nov. is described from Hokkaido, Japan and Magadan, Far East Russia based on morphological observations and molecular analyses using mitochondrial cox3 and chloroplast rbcL genes. This new species is distinguished from other Colpomenia by its small globular to ovoidal thallus up to 5 cm in diameter, and thin thallus membrane composed of a cortex of one to two‐cell layers and a colorless medulla of up to three layers. This species is epiphytic on the brown alga Stephanocystis in areas protected against waves. The life history in culture of C. borea was investigated and the observed life history pattern was similar to those reported in C. peregrina and C. sinuosa. Our phylogenetic analyses supported that C. borea is a distinct species, yet it is more related to C. peregrina than C. sinuosa.
  • Eriko Sasagawa, Wilfred John E. Santianez, Kazuhiro Kogame
    PHYCOLOGICAL RESEARCH 2022年06月 
    Members of the brown algal order Asterocladales are characterized by stellate arrangement of its chloroplasts, in which a stellate configuration has a protruding central pyrenoid complex. The order is represented by the genus Asterocladon, which consists of only three species so far. Similar to other small and filamentous seaweeds, studies on Asterocladon remain scant and their diversity poorly understood. To fill this gap, we conducted molecular-assisted taxonomic studies on Asterocladon based on seven culture isolates collected from Okinawa Prefecture, Japan and Cebu, the Philippines. One culture isolate from the Philippines was revealed to be a new species of Asterocladon based on morpho-anatomical and molecular analyses using rbcL and psaA genes and is described here as Asterocladon ednae. The other isolates were attributed to A. rhodochortonoides. A. ednae was most closely related to A. rhodochortonoides in morphology and molecular phylogeny but was distinguished from the latter by its elongately ellipsoid plurilocular sporangia. This is the first report of the genus and species A. ednae in the Philippines, further increasing the diversity of seaweeds in the country.
  • Yukimasa Yamagishi, Kazuhiro Kogame, Michio Masuda
    PHYCOLOGICAL RESEARCH 70 2 118 - 128 2022年04月 
    A new red alga from Japan, Dasya japonovillosa, is described. This new species and D. enomotoi, both of which have elongated axes densely covered with numerous soft monosiphonous filaments, may have been misidentified as D. villosa by previous investigators in Japan. Dasya villosa differs from D. japonovillosa and D. enomotoi in the distinct five pericentral cells in transverse sections and palisade-like tetrasporangial cover cells. The new species is distinguished from several similar species by the combination of the following: an elongated axis (to 65 cm), subdichotomously divided axes and polysiphonous branches, indistinct pericentral cells in transverse sections except near the apices, and the presence of enlarged, inner cortical cells, radially arranged numerous soft monosiphonous filaments, three-celled carpogonial branches, four tetrasporangia in each fertile segment of the stichidia, and one (rarely two) tetrasporangial cover cell that is not elongated longitudinally and rarely divided transversely.
  • Manzaea minuta gen. & comb. nov. (Scytosiphonaceae, Phaephyceae) from the tropical northwestern Pacific Ocean
    Wilfred John E. Santiañez and Kazuhiro Kogame
    Philippine Journal of Systematic Biology 16 1 2022年 [査読有り]
  • Masakazu Hoshino, Shimpei F Hiruta, Maria Emilia Croce, Mitsunobu Kamiya, Takahiro Jomori, Toshiyuki Wakimoto, Kazuhiro Kogame
    Molecular ecology 30 22 5814 - 5830 2021年11月 
    Geographical parthenogenesis, a phenomenon where parthenogens and their close sexual relatives inhabit distinct geographical areas, has been considered an interesting topic in evolutionary biology. Reports of geographical parthenogenesis from land and freshwater are numerous, but this occurrence has been rarely reported from the sea. Brown algae are mostly marine and are thought to include numerous obligate parthenogens; still, little is known about the distribution, origin and evolution of parthenogens in this group. Here we report a novel pattern of geographical parthenogenesis in the isogamous brown alga Scytosiphon lomentaria. Sex ratio investigation demonstrated that, in Japan, sexual populations grew in the coast along warm ocean currents, whereas female-dominant parthenogenetic populations grew mainly in the coast along a cold ocean current. In the two localities where sexual and parthenogenetic populations were parapatric, parthenogens grew in more wave-exposed areas than sexuals. Population genetic and phylogenetic analyses, including those based on genome-wide single nucleotide polymorphism data, indicated that parthenogens have initially evolved at least twice and subsequent hybridizations between the parthenogens and sexuals have generated multiple new parthenogenetic lineages. The origin of the initial parthenogens is not clear, except that it would not be interspecies hybridization. Interestingly, we found that the production of sex pheromones, which attract male gametes, has been independently lost in the initial two parthenogenetic lineages. This parallel loss of the sexual trait may represent the direct origin of parthenogens, or the regressive evolution of a useless trait under asexuality.
  • Systematics, distribution, and sexual compatibility of six Scytosiphon species (Scytosiphonaceae, Phaeophyceae) from Japan and the description of four new species
    asakazu Hoshino, Atsuko Tanaka, Mitsunobu Kamiya, Shinya Uwai, Masanori Hiraoka, Kazuhiro Kogame
    Journal of Phycology 57 416 - 434 2021年 [査読有り]
  • Masakazu Hoshino, Chihiro Ino, Taiju Kitayama, Kazuhiro Kogame
    PHYCOLOGICAL RESEARCH 68 4 290 - 297 2020年10月 [査読有り]
     
    The rare red algaSchimmelmannia(Schimmelmanniaceae, Acrosymphytales) from Japan was taxonomically re-examined in this study. JapaneseSchimmelmanniahas previously been identified asS. plumosa(Setchell) I.A.Abbott. However, JapaneseSchimmelmanniaandS. plumosahave approximately 5 and 1.9% of genetic distance in mitochondrialcox1 and chloroplastrbcL sequences, respectively. They also differ morphologically in the numbers of periaxial cells and auxiliary cell branches indicating that they are distinct species. Based on molecular phylogenetics and morphology,S. benzaitenianais distinguishable from otherSchimmelmanniaspecies, except forS. bolleiMontagne which lacks a detailed description. SinceS. bolleihas been reported only from the North Atlantic coast of Africa, we assumed that it is distinct from the Japanese species. We, therefore, described the Japanese species as a new species,S. benzaiteniana.
  • Ailen M. Poza, Wilfred John E. Santianez, M. Emilia Croce, M. Cecilia Gauna, Kazuhiro Kogame, Elisa R. Parodi
    JOURNAL OF PHYCOLOGY 56 5 1349 - 1361 2020年10月 [査読有り]
     
    We evaluated the life cycle ofLeathesia marinathrough molecular analyses, culture studies, morphological observations, and ploidy measurements. Macroscopic sporophytes were collected from two localities in Atlantic Patagonia and were cultured under long-day (LD) and short-day (SD) conditions. Molecular identification of the microscopic and macroscopic phases was performed through thecox3 andrbcL genes and the phylogeny was assessed on the basis of single gene and concatenated datasets. Nuclear ploidy of each phase was estimated from the DNA contents of individual nuclei through epifluorescence microscopy and flow cytometry. Molecular results confirmed the identity of the Argentinian specimens asL. marinaand revealed their conspecificity withL. marinafrom New Zealand, Germany, and Japan. The sporophytic macrothalli (2n) released mitospores from plurilocular sporangia, which developed into globular microthalli (2n), morphologically similar to the sporophytes but not in size, constituting a generation of small diploid thalli, with a mean fluorescent nuclei cross-sectional area of 3.21 +/- 0.7 mu m(2). The unilocular sporangia released meiospores that developed two morphologically different types of microthalli: erect branched microthalli (n) with a nuclear area of 1.48 +/- 0.07 mu m(2)that reproduces asexually, and prostrate branched microthalli (n) with a nuclear area of 1.24 +/- 0.10 mu m(2)that reproduces sexually. The prostrate microthalli released gametes in LD conditions, which merged and produced macroscopic thalli with a nuclear cross-sectional area of 3.45 +/- 0.09 mu m(2). Flow cytometry confirmed that the erect and prostrate microthalli were haploid and that the globular microthalli and macrothalli were diploid.
  • Wilfred John E. Santianez, Dhia Al-bader, John A. West, John J. Bolton, Kazuhiro Kogame
    PHYCOLOGICAL RESEARCH 68 4 323 - 331 2020年10月 [査読有り]
     
    The taxonomy, classification, and phylogenetic relationships of the brown seaweed genusIyengariawith other members of the family Scytosiphonaceae remain poorly understood. In this study, we addressed some problems in the systematics (taxonomic and classification status) and phylogenetic position ofIyengariabased on our studies on the generitypeIyengaria stellatafrom Kuwait and South Africa. We confirm thatI. stellatais conspecific withColpomenia capensisbased on molecular and morpho-anatomical data and that the species has a disjunct distribution within the Indian Ocean. Also, the distinguishing features of twoIyengariaspecies (I. nizamuddiniiand 'I. lobocylindrica') described from Karachi, Pakistan, are within the morphological range ofI. stellata. Hence, these two taxa are considered here as junior heterotypic synonyms ofI. stellata. Our molecular phylogenetic analyses suggested the paraphyly of the genusIyengaria, with the recently describedIyengaria quadriseriatafrom India forming close associations withRosenvingea intricata. As such, we removeI. quadriseriatafrom the genusIyengariaand relegate it as a synonym ofR. intricata. Consequently, by recognizing only one species, our proposals considerably reduce the species diversity in the genus. Moreover, our culture studies suggested thatI. stellataexhibits an alternation of heteromorphic generations, similar to other species in the Scytosiphonaceae. Under culture conditions,I. stellataalso produced plurangia on microthalli, confirming its affinity with other phylogenetically close relatives in the 'Hydroclathrusgroup' of the family Scytosiphonaceae such asColpomenia,Rosenvingea, andChnoospora.
  • Masakazu Hoshino, Maria Emilia Croce, Takeaki Hanyuda, Kazuhiro Kogame
    PHYCOLOGIA 59 2 116 - 126 2020年03月 [査読有り]
     
    Molecular phylogenetic analyses based on mitochondrial cox1 and cox3 and chloroplast rbcL gene sequences revealed that the morphospecies of the brown alga Planosiphon gracilis (Scytosiphonaceae, Ectocarpales) from Japan is a complex of three distinct lineages (lineages I-III). Specimens from these lineages had the typical morphology of Pl. gracilis (i.e. flattened, linear, hollow, and gregarious erect thalli); thus, morphological discrimination among them was difficult in many cases. We observed large genetic divergences among the three lineages (c. 10% in cox1 and cox3). Moreover, we observed a reproductive isolating barrier between lineages I and II, despite the wide overlap in their geographic distribution. Our data, therefore, suggest that these three lineages are distinct species. Since lineage I included the holotype specimen of Pl. gracilis, this lineage was attributed to Pl. gracilis. Lineage III was phylogenetically close to Pl. complanatus from Canada with a 4.1% divergence in cox1. For lineage II, a new species name, Pl. nakamurae sp. nov., was proposed. This new species was also found in Argentina.
  • Boo, G. H, Qiu, Y, Kim, J. Y, Ang, P, Bosch, S, De Clerck, O, He, P, Higa, A, Huang, B, Kogame, K, Liu, S. L, Nguyen, T. V, Suda, S, Terada, R, Thiamdao, S, Miller, K. A, Boo, S. M
    Journal of Phycology 55 6 1319 - 1334 2019年11月 [査読有り][通常論文]
  • Masakazu Hoshino, Kazuhiro Kogame
    JOURNAL OF PHYCOLOGY 55 2 466 - 472 2019年04月 [査読有り]
     
    Parthenogenetic development of unfused gametes is commonly observed in laboratory cultures among various brown algal taxa. There is, however, little information on the contribution of parthenogenesis to the reproduction of field populations. In this study, we investigated whether parthenogenesis is present in a sexual population of the isogamous brown alga Scytosiphon with a 1:1 sex ratio. In culture, both female and male gametes showed higher mortality and slower development compared to zygotes. More than 90% of surviving partheno-germlings formed parthenosporophytes irrespective of the culture conditions tested. Therefore, if parthenogenesis occurs in the field, most unfused gametes are expected to form parthenosporophytes. Contrary to this expectation, parthenosporophytes were rare in the field population. We collected 126 sporophytic thalli and isolated and cultured a unilocular sporangium from each of them. We confirmed that cultures of 120 unilocular sporangia produced both female and male gametophytes by the observation of zygotes or amplification of PCR-based sex markers indicating that these sporangia originated from zygotic sporophytes. Only females were detected in cultures from two sporangia and only males from four sporangia suggesting that these sporangia originated from parthenosporophytes. In the Scytosiphon population, although parthenogenesis is observable in culture, our results demonstrate that the contribution of parthenogenesis to reproduction is small (<= 4.8%) compared to sexual reproduction. Unfused gametes may not survive to form mature parthenosporophytes in significant numbers in the field partly due to their higher mortality and slower development compared from zygotes.
  • Wilfred John E. Santianez, Kazuhiro Kogame
    BOTANICA MARINA 62 2 149 - 153 2019年04月 [査読有り]
     
    The brown algal family Scytosiphonaceae has recently received considerable attention resulting in the description of several new genera and species. However, members of the genus Scytosiphon and Petalonia remain polyphyletic. By integrating multi-gene phylogenetic data (mitochondrial cox3 and plastid psaA and rbcL genes) with their known morpho-anatomies and life histories, we herein resurrect Hapterophycus canaliculatus, currently considered a member of genus Scytosiphon, and transfer Scytosiphon tenellus to the genus Petalonia.
  • Agnieszka P. Lipinska, Martha L. Serrano-Serrano, Alexandre Cormier, Akira F. Peters, Kazuhiro Kogame, J. Mark Cock, Susana M. Coelho
    GENOME BIOLOGY 20 2019年02月 [査読有り]
  • Hoshino Masakazu, Okino Tatsufumi, Kogame Kazuhiro
    JOURNAL OF PHYCOLOGY 55 1 204 - 213 2019年02月 [査読有り][通常論文]
  • Suttikarn Sutti, Masaya Tani, Yukimasa Yamagishi, Tsuyoshi Abe, Kathy Ann Miller, Kazuhiro Kogame
    Phycologia 57 3 262 - 272 2018年03月15日 [査読有り][通常論文]
     
    Using morphological and molecular evidence, we describe a new genus, Neochondria, based on specimens formerly identified as 'Chondria tenuissima' sensu Okamura in Japan. The generitype, Neochondria ammophila sp. nov., is not closely related to Chondria capillaris (Hudson) M.J. Wynne, the generitype of Chondria. The anatomy of Neochondria differs from that of Chondria by the development of adventitious elongate cells between the five major pericentral cells, forming densely compact layers surrounding the axial strand, even in the ultimate branchlets. We propose the new combination, Neochondria nidifica, based on Chondria nidifica Harvey from California, USA and Baja California, Mexico. Multigene analyses (rbcL, small subunit and cox1) and morphological observations demonstrated that N. ammophila and N. nidifica share a clade but preliminary results show that they may not belong in the tribe Chondrieae.
  • Masakazu Hoshino, Shozo Ishikawa, Kazuhiro Kogame
    Phycologia 57 2 232 - 242 2018年01月11日 [査読有り][通常論文]
     
    DNA-based species delimitation methods often predict many putative cryptic species. Interpretation of these putative species (i.e. do they represent distinct species, or is this an erroneous estimate based on DNA variability?) is challenging because estimates of DNA-based delimitation are often difficult to verify using nongenetic data such as morphology or geographical distribution. In the present study, estimates of DNA-based delimitation methods were verified based on the biological species concept in Japanese populations of Scytosiphon lomentaria. Three DNA-based species delimitation methods (Generalised Mixed Yule Coalescent, Poisson Tree Processes and Automatic Barcode Gap Discovery) were conducted using mitochondrial (cox1) and nuclear (second intron of centrin gene) DNA sequence datasets. In the S. lomentaria species complex, five putative cryptic species (Ia–Va) were well-supported by DNA-based species delimitation, and these putative species were often found in the same locality. To verify the estimates of DNA-based delimitation, crossing experiments were conducted among the putative species, using cultured isolates. Gametic incompatibility, which prevented hybrid zygote formation, was observed among them, except in the crosses between species IIa male and species IIIa female, in which hybrid zygotes successfully formed. These hybrid zygotes grew up to sporophytes and matured with unilocular sporangia in culture however, the survival rate of their meiospores (zoospores) was significantly lower than that of meiospores from sporophytes derived from intraspecific crosses. In the S. lomentaria species complex in Japan, well-supported DNA-based species boundaries were concordant with biological species boundaries (intrinsic barriers to gene exchange). The five cryptic species are reproductively isolated from each other by gametic incompatibility (pre-zygotic barrier) and low survival rate of hybrid meiospores (post-zygotic barrier).
  • Wilfred John E. Santiañez, Erasmo C. Macaya, Kyung Min Lee, Ga Youn Cho, Sung Min Boo, Kazuhiro Kogame
    Botanica Marina 61 1 47 - 64 2018年01月10日 [査読有り][通常論文]
     
    A new and putatively endemic species of Hydroclathrus, Hydroclathrus rapanuii, is described from the geographically isolated Easter Island in the southeastern Pacific based on morphological and molecular phylogenetic data. It is distinguished from other Hydroclathrus by thalli of unevenly furrowed thin membranes, and angular, block-like plurangial sori. Our phylogenetic analyses indicated that H. rapanuii is closely related to the generitype Hydroclathrus clathratus. We also report on the morphology and phylogeny of Chnoospora minima from Easter I. and elsewhere in the Indo-Pacific Ocean, noting the previously unreported presence of hollow portions in its medulla. Although not collected from Easter I., we herein propose the recognition of two new genera, Dactylosiphon gen. nov. and Pseudochnoospora gen. nov., based on our three-gene phylogeny and their known morphologies and anatomies. Dactylosiphon is based on the three species currently assigned to Colpomenia (C. bullosa, C. durvillei, and C. wynnei) that are genetically and morphologically (i.e. thalli with erect and finger-like tubes arising from a common saccate base) distinct from other members of Colpomenia. The monotypic genus Pseudochnoospora is represented by the decumbent, branching, and inter-adhesive species currently known as Chnoospora implexa. With the above proposals, we further increase the genus-level diversity of Scytosiphonaceae in the Indo-Pacific Ocean.
  • Wilfred John E. Santiañez, Kyung Min Lee, Shinya Uwai, Akira Kurihara, Paul John L. Geraldino, Edna T. Ganzon-Fortes, Sung Min Boo, Kazuhiro Kogame
    Phycologia 57 1 61 - 78 2018年 [査読有り][通常論文]
     
    Among the distinctive members of the brown algal family Scytosiphonaceae is the genus Hydroclathrus, which is primarily distinguished by its clathrate (net-like) appearance. Hydroclathrus, despite being seasonal and species poor, is a conspicuous floristic component in many tropical to warm temperate coasts. However, compared with other closely related genera, such as Colpomenia and Rosenvingea, Hydroclathrus remains poorly known its taxonomy remains problematic, as information on the molecular phylogenetic relationships of the species is still scarce. We attempted to bridge these gaps by describing the diversity and molecular phylogeny of Hydroclathrus based on morphological and genetic (mitochondrial cox1 and cox3 and plastidial psaA and rbcL genes) data. We recognised four Hydroclathrus species: H. clathratus, H. stephanosorus, H. tenuis and H. minutus sp. nov., which is morphologically cryptic to H. tenuis. A new clathrate genus, Tronoella ryukyuana gen. & sp. nov., is also erected based on specimens from southern Japan. Tronoella is primarily distinguished from Hydroclathrus in possessing (1) highly convoluted thalli with branches that are sometimes slightly twisted and/or interadhesive (2) siphonous protrusions that grow randomly and in various directions, later on becoming perforated branches with revolute margins and (3) plurangia that are firmly coherent and massive. Our results highlight the need to re-evaluate the identity of the species reported as H. clathratus and H. tenuis and underscore the need to re-examine the taxonomy and systematics of the family Scytosiphonaceae.
  • Transfer of Petalonia filiformis (Batters) Kuntze to the genus Planosiphon McDevit & G.W.Saunders (Scytosiphonaceae, Phaeophyceae)
    Wilfred John, E. Santiañez, Kazuhiro Kogame
    Notulae algarum 40 2017年10月 [査読有り][通常論文]
  • K. Kogame, S. Uwai, R. J. Anderson, H. -G. Choi, J. J. Bolton
    SOUTH AFRICAN JOURNAL OF BOTANY 108 337 - 341 2017年01月 [査読有り][通常論文]
     
    COI (cytochrome c oxidase subunit 1) barcoding has been increasingly applied to geniculate coralline red algae, and has led to many taxonomic revisions, but mainly in samples from the northern hemisphere. In the present study, COI barcoding was conducted on new collections of 63 samples of geniculate corallines from South Africa to test the currently accepted morphological classification, including species of Amphiroa, Arthrocardia, Cheilosporum, Corallina, Haliptilon and Jania. The morphological classification matched the genetic data for most genera and species. However, there were significant differences within the genus Arthrocardia. Seven probable species of this genus were suggested, including two unidentified species, showing a clear need for taxonomic revision. Four Amphiroa species each formed a clade, but South African samples of A. beauvoisii were considered to be distinct from a sample from North Carolina based on sequence differences. Seven samples of Corallina positioned near C. caespitosa but not C. officinalis. Although the latter name is commonly attributed to South African Corallina, this provides evidence that C. officinalis is absent from South Africa. A combination of morphological identification and COI barcoding has been shown to be a useful tool in the delineation of species in this ecologically important group of seaweeds. (C) 2016 SAAB. Published by Elsevier B.V. All rights reserved.
  • Masahiro Suzuki, Takahiro Segawa, Hiroshi Mori, Ayumi Akiyoshi, Ryo Ootsuki, Akira Kurihara, Hidetoshi Sakayama, Taiju Kitayama, Tsuyoshi Abe, Kazuhiro Kogame, Hiroshi Kawai, Hisayoshi Nozaki
    PLOS ONE 11 7 2016年07月 [査読有り][通常論文]
     
    Liagora japonica is a red algal species distributed in temperate regions of Japan. This species has not been collected from its type locality on the Pacific coast of Japan since 1927 and seems to have become extinct in this area. For molecular characterization of L. japonica, we extracted DNA from the topotype material of L. japonica collected in 1927, analyzed seven genes using Illumina next-generation sequencing, and compared these data with sequences from modern samples of similar red algae collected from the Japan Sea coast of Japan. Both morphological and molecular data from modern samples and historical specimens (including the lectotype and topotype) suggest that the specimens from the Pacific and Japan Sea coasts of Japan should be treated as a single species, and that L. japonica is phylogenetically separated from the genus Liagora. Based on the phylogenetic results and examination of reproductive structures, we propose Otohimella japonica gen. et comb. nov., characterized morphologically by diffuse carposporophytes, undivided carposporangia, and involucral filaments initiated only from the cortical cell on the supporting cell.
  • Motoshi Kunugi, Soichirou Satoh, Kunio Ihara, Kensuke Shibata, Yukimasa Yamagishi, Kazuhiro Kogame, Junichi Obokata, Atsushi Takabayashi, Ayumi Tanaka
    PLANT AND CELL PHYSIOLOGY 57 6 1231 - 1243 2016年06月 [査読有り][通常論文]
     
    Photosynthetic organisms have various pigments enabling them to adapt to various light environments. Green plants are divided into two groups: streptophytes and chlorophytes. Streptophytes include some freshwater green algae and land plants, while chlorophytes comprise the other freshwater green algae and seawater green algae. The environmental conditions driving the divergence of green plants into these two groups and the changes in photosynthetic properties accompanying their evolution remain unknown. Here, we separated the core antennae of PSI and the peripheral antennae [light-harvesting complexes (LHCs)] in green plants by green-native gel electrophoresis and determined their pigment compositions. Freshwater green algae and land plants have high Chl a/b ratios, with most Chl b existing in LHCs. In contrast, seawater green algae have low Chl a/b ratios. In addition, Chl b exists not only in LHCs but also in PSI core antennae in these organisms, a situation beneficial for survival in deep seawater, where blue-green light is the dominant light source. Finally, low-energy Chl (red Chl) of PSI was detected in freshwater green algae and land plants, but not in seawater green algae. We thus conclude that the different level of Chl b accumulation in core antennae and differences in PSI red Chl between freshwater and seawater green algae are evolutionary adaptations of these algae to their habitats, especially to high-or low-light environments.
  • Ga Hun Boo, Il Ki Hwang, Dong Su Ha, Kathy Ann Miller, Kazuhiro Kogame, Ga Youn Cho, Jung Yeon Kim, Sung Min Boo
    PHYCOLOGIA 55 1 3 - 11 2016年 [査読有り][通常論文]
     
    Four species have been described in the genus Pikea (Dumontiaceae, Gigartinales): three species from North America and one species from Japan. However, the phylogeny and species delimitation in Pikea remain poorly resolved. Here we provide both rbcL and cox1 sequences for all species of Pikea, including the type of P. pinnata and a paratype of P. robusta. Our data reveal that P. californica, P. pinnata and P. yoshizakii are distinct in both data sets, but P. robusta is synonymous with the earlier-described P. pinnata. Morphological and molecular data show that Pikea from Korea is identical to P. yoshizakii and that the previous report of P. californica in Korea is a misidentification. The genus Pikea is well resolved in the main clade of the Dumontiaceae. This is the first study on the phylogeny of Pikea using rbcL and cox1 sequence data.
  • Kousuke Yaegashi, Yukimasa Yamagishi, Shinya Uwai, Tsuyoshi Abe, Wilfred John Eria Santianez, Kazuhiro Kogame
    BOTANICA MARINA 58 5 331 - 343 2015年10月 [査読有り][通常論文]
     
    The brown algal genus Acinetospora is characterised by sparsely branched uniseriate filaments, scattered meristematic zones, short laterals ("crampons") and scattered reproductive organs. The morphology and life history of the generitype A. crinita have been studied repeatedly, and accounts of the species' highly varied reproductive patterns were assumed to be due to the presence of multiple taxa that were reported under this name. Herein, we attempt to contribute to the taxonomy of the genus by conducting morphological and culture studies on 33 Acinetospora samples collected from Japan. We recognised two Acinetospora species and propose to name them A. filamentosa comb. nov. and A. asiatica sp. nov. These two species are distinguished from A. crinita by the absence of monosporangia and plurilocular acinetosporangia/megasporangia. Acinetospora filamentosa and A. asiatica have similar vegetative morphologies but possess different reproductive patterns. The former forms unilocular sporangia on erect filaments and both unilocular sporangia and plurilocular zoidangia on prostrate filaments, while the latter forms plurilocular zoidangia only on both erect and prostrate filaments. Molecular analyses based on rbcL and cox1 genes supported independence of these species.
  • Kazuhiro Kogame, Shozo Ishikawa, Kei Yamauchi, Shinya Uwai, Akira Kurihara, Michio Masuda
    PHYCOLOGICAL RESEARCH 63 3 167 - 177 2015年07月 [査読有り][通常論文]
     
    Scytosiphon lomentaria (Scytosiphonaceae, Ectocarpales) is believed to include some cryptic species, particularly in the Pacific. We attempted to delimit these species in Japan using mitochondrial cox1 and cox3 and nuclear ITS2 and the second intron of the centrin gene (cetn-int2). Fifty-three cox1+cox3 mitotypes, 26 ITS2 ribotypes and 45 cetn-int2 haplotypes were found in 107 samples collected from 33 localities in Japan. Based on phylogenetic analyses, similar sequence types were grouped into ten mitogroups, eight ribogroups and six cetn-int2 haplogroups (sequence-type groups). From the molecular trees and combinations of the mito-, ribo- and haplogroups, three cryptic species were apparent (Groups I-III). Group I, widely distributed on Pacific coasts, was highly supported by all molecular trees, whereas Groups II (North Pacific) and III (Northwestern Pacific and Australasia) were more closely related to each other. However, sequence-type-group combinations that would be characteristic of hybrids between Groups II and III were not detected, suggesting no gene flow between the two Groups. Further investigations of an additional 127 sympatrically growing plants supported the absence of gene flow between Groups II and III. Four samples did not belong to any of the Groups I-III and possibly represent additional species.
  • Kyoko Hagino, Jeremy R. Young, Paul R. Bown, Jelena Godrijan, Denise K. Kulhanek, Kazuhiro Kogame, Takeo Horiguchi
    MARINE MICROPALEONTOLOGY 116 28 - 37 2015年04月 [査読有り][通常論文]
     
    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.
  • Kazuhiro Kogame, Fabio Rindi, Akira F. Peters, Michael D. Guiry
    PHYCOLOGIA 54 4 367 - 374 2015年 [査読有り][通常論文]
     
    The common brown alga Scytosiphon lomentaria (Scytosiphonaceae) has generally been regarded as a species complex. In the Pacific, molecular data have shown that it includes more than one species; the diversity in other oceans, however, has not been examined. In the present study, the genetic diversity of S. lomentaria was investigated in 57 samples from the north-east Atlantic (mainly from Ireland) and two from the Mediterranean, which were compared with seven samples from Japan. Phylogenetic analyses based on the mitochondrial cytochrome oxidase subunit 3 gene (cox3) and nuclear ribosomal internal transcribed spacers (ITS1 and 2) revealed four separate monophyletic groups. Clades A1 and A2 consisted of the samples from the north-east Atlantic; the Mediterranean samples also belonged to A1. The affiliation of four samples was incongruent between cox3 and ITS trees, suggesting directional mitochondrial introgression from A2 to A1. Clades P1 and P2 contained nine samples from the north-east Atlantic, i. e. three Irish, all Norwegian and Icelandic samples, as well as all Pacific samples; in these clades, the cox3 and ITS data were congruent. This is the first documented record of Pacific lineages of Scytosiphon in the north-east Atlantic. Our results indicate that at least four species are passing under the name S. lomentaria in the north-east Atlantic and the Mediterranean.
  • Kyung Min Lee, Rafael Riosmena-Rodriguez, Kazuhiro Kogame, Sung Min Boo
    PHYCOLOGIA 53 5 480 - 487 2014年 [査読有り][通常論文]
     
    The taxonomic distinctiveness and distribution of the brown alga Colpomenia phaeodactyla are debatable. The type locality of this species is Puerto Penasco, Mexico, and its distribution includes northeast Asia. We analyzed two gene sequences of specimens of so-called C. phaeodactyla from Korea, Japan and Mexico, in combination with morphological observations of the specimens. Analyses of 71 cox3 and 23 rbcL sequences resulted in similar trees in which specimens under the name C. phaeodactyla consisted of two distinct clades. One clade comprised samples from Korea and Japan, and the other clade, from the Gulf of California, was identical to C. durvillei. Additional observations of the morphology and anatomy of the specimens agreed with the molecular data. On the basis of these results, we describe the new species C. wynnei for plants from Korea and Japan. Colpomenia wynnei was distinguished by finger-like sacs with adventitious branchlets when mature and was much contorted, the height of ascocysts being shorter than plurilocular sporangia. Both cox3 and rbcL sequence data strongly supported the monophyly of C. wynnei, C. bullosa and C. durvillei, all being characterized by having elongate thalli. Based on both cox3 and rbcL data sets, we herein propose to synonymise C. phaeodactyla with C. durvillei.
  • Takahiro Wakahama, Aitor Laza-Martinez, Ahmad Iskandar Bin Haji Mohd Taha, Hidetoshi Okuyama, Kiyohito Yoshida, Kazuhiro Kogame, Koichiro Awai, Masanobu Kawachi, Takashi Maoka, Shinichi Takaichi
    JOURNAL OF PHYCOLOGY 48 6 1392 - 1402 2012年12月 [査読有り][通常論文]
     
    The molecular structure of the carotenoid lactoside P457, (3S,5R,6R,3'S,5'R,6'S)-13'-cis-5,6-epoxy-3',5'-dihydroxy-3-(beta-d-galactosyl-(1?4)-beta-d-glucosyl)oxy-6',7'-didehydro-5,6,7,8,5',6'-hexahydro-beta,beta-caroten-20-al, was confirmed by spectroscopic methods using Symbiodinium sp. strain NBRC 104787 cells isolated from a sea anemone. Among various algae, cyanobacteria, land plants, and marine invertebrates, the distribution of this unique diglycosyl carotenoid was restricted to free-living peridinin-containing dinoflagellates and marine invertebrates that harbor peridinin-containing zooxanthellae. Neoxanthin appeared to be a common precursor for biosynthesis of peridinin and P457, although neoxanthin was not found in peridinin-containing dinoflagellates. Fucoxanthin-containing dinoflagellates did not possess peridinin or P457; green dinoflagellates, which contain chlorophyll a and b, did not contain peridinin, fucoxanthin, or P457; and no unicellular algae containing both peridinin and P457, other than peridinin-containing dinoflagellates, have been observed. Therefore, the biosynthetic pathways for peridinin and P457 may have been coestablished during the evolution of dinoflagellates after the host heterotrophic eukaryotic microorganism formed a symbiotic association with red alga that does not contain peridinin or P457.
  • Gerald Blunden, Michael D. Guiry, Louis D. Druehl, Kazuhiro Kogame, Hiroshi Kawai
    NATURAL PRODUCT COMMUNICATIONS 7 7 863 - 865 2012年07月 [査読有り][通常論文]
     
    A collection of Laminariales species was made with examples in each of the presently recognized families of the order. Extracts of each species were examined for betaines, using primarily H-1 NMR spectroscopy for their identification. Glycinebetaine was detected in all species tested and would appear to be a consistent feature of the Laminariales. gamma-Aminobutyric acid betaine was found in all species of Laminaria examined and in three of the five Saccharina species (family Laminariaceae), but was not detected in species of either other genera of the family or in those of other Laminariales families. Trigonelline was found in some Laminaria and Saccharina species, as well as in the north Pacific species Postelsia palmaeformis (Laminariaceae), Pseudochorda nagaii (Pseudochordaceae) and Akkesiphycus lubricus (Akkesiphycaceae).
  • 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 2011年10月 [査読有り][通常論文]
     
    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.
  • Kazuhiro Kogame, Akira Kurihara, Ga Youn Cho, Kyung Min Lee, Alison R. Sherwood, Sung Min Boo
    PHYCOLOGIA 50 5 563 - 573 2011年09月 [査読有り][通常論文]
     
    A new brown alga Petalonia tatewakii sp. nov. (Scytosiphonaceae) is described from the Hawaiian Islands based on morphological observations and phylogenetic analyses of DNA sequences of the chloroplast-encoded rbeL. gene and the ITS1-5.8S-ITS2 region of the nuclear ribosomal cistron. The thalli are linear and complanate, up to 15 cm in length and 0.8 cm in width with rhizoidal filaments in the medulla. This species is morphologically distinguishable from other Petalonia species by having ascocysts among plurilocular zoidangia. Molecular phylogenetic analyses revealed that samples of P. tatewakii form a distinct clade that is sister to the clade of P. binghamiae (J. Agardh) Vinogradova. All our collections of Hawaiian Petalonia from the main Hawaiian Islands were assigned to P. tatewakii.
  • Kei Kimura, Chikako Nagasato, Kazuhiro Kogame, Taizo Motomura
    JOURNAL OF PHYCOLOGY 46 1 143 - 152 2010年02月 [査読有り][通常論文]
     
    Mitochondrial DNA (mtDNA) of the isogamous brown alga Scytosiphon lomentaria (Lyngb.) Link is inherited maternally. We used molecular biological and morphological analyses to investigate the fate of male mitochondria. Ultrastructural observations showed that the number of 25 mitochondria in a zygote coincided with the number of mitochondria derived from male and female gametes. This number remained almost constant during the first cell division. Strain-specific PCR in single germlings suggested that mtDNA derived from the female gamete remained in the germling during development, while the male mtDNA gradually and selectively disappeared after the four-cell stage. One week after fertilization, male mtDNA had disappeared in sporophytic cells. Using bisulfite DNA modification and methylation mapping assays, we found that the degree of methylation on three analyzed sites of mtDNA was not different between male and female gametes, suggesting that maternal inheritance of mtDNA is not defined by its methylation. This study indicates that the mechanism of selective elimination of male mtDNA is present in each cell of a four-celled sporophyte and that it does not depend on different degrees of DNA methylation between male and female mtDNA.
  • Shinya Uwai, K. Kogame, G. Yoshida, H. Kawai, T. Ajisaka
    MARINE BIOLOGY 156 5 901 - 911 2009年04月 [査読有り][通常論文]
     
    The genetic structure and phylogeography of the brown seaweed Sargassum horneri/filicinum complex in Japan were studied based on the mitochondrial cox3 haplotype. The cox3 haplotypes found were divided into three clades in a statistical parsimony network, among which there were large numbers of steps. Contrary to the reported large amount of drifting S. horneri along the Japanese coast, the three clades were dividedly distributed on the Japanese coast: the northern Pacific, the central Pacific, and western Japan. The western Japan S. horneri had haplotypes that were phylogenetically closer to those of S. filicinum than to the northern and central Pacific S. horneri populations. The S. filicinum populations were included within the western Japan clade and grouped together with the S. horneri samples from western Japan. Taken together with the unstable morphological diagnosis, this result suggests that S. filicinum should be reduced into a synonymy of S. horneri. The TMRCA analysis suggested that the divergence time of each clade may go back to the last interglacial period and a skyline plot suggested that the last glacial maximum had only a small effect on the population size of S. horneri. The geographic subdivision of the three groups, in spite of a large amount of drifting mats, suggests a limited contribution of drifting mats to gene flow on a large geographic scale. On a small geographic scale, a small number of haplotypes were shared between S. horneri-type and S. filicinum-type populations. This result suggests that populations of these two types are partially, though not completely, isolated from each other, possibly by selfing in S. filicinum-type populations or by a difference in peak reproduction.
  • Shinya Uwai, K. Kogame, G. Yoshida, H. Kawai, T. Ajisaka
    MARINE BIOLOGY 156 5 901 - 911 2009年04月 [査読有り][通常論文]
     
    The genetic structure and phylogeography of the brown seaweed Sargassum horneri/filicinum complex in Japan were studied based on the mitochondrial cox3 haplotype. The cox3 haplotypes found were divided into three clades in a statistical parsimony network, among which there were large numbers of steps. Contrary to the reported large amount of drifting S. horneri along the Japanese coast, the three clades were dividedly distributed on the Japanese coast: the northern Pacific, the central Pacific, and western Japan. The western Japan S. horneri had haplotypes that were phylogenetically closer to those of S. filicinum than to the northern and central Pacific S. horneri populations. The S. filicinum populations were included within the western Japan clade and grouped together with the S. horneri samples from western Japan. Taken together with the unstable morphological diagnosis, this result suggests that S. filicinum should be reduced into a synonymy of S. horneri. The TMRCA analysis suggested that the divergence time of each clade may go back to the last interglacial period and a skyline plot suggested that the last glacial maximum had only a small effect on the population size of S. horneri. The geographic subdivision of the three groups, in spite of a large amount of drifting mats, suggests a limited contribution of drifting mats to gene flow on a large geographic scale. On a small geographic scale, a small number of haplotypes were shared between S. horneri-type and S. filicinum-type populations. This result suggests that populations of these two types are partially, though not completely, isolated from each other, possibly by selfing in S. filicinum-type populations or by a difference in peak reproduction.
  • Eun Chan Yang, Ga Youn Cho, Kazuhiro Kogame, Amy Lynn Carlile, Sung Min Boo
    BOTANICA MARINA 51 5 370 - 377 2008年10月 [査読有り][通常論文]
     
    Ceramium kondoi is a morphologically variable ceramiaceous red alga that occurs commonly in the northwest Pacific Ocean region and has recently been reported in the United States. Forty-five specimens of C. kondoi from 29 locations in Korea, Japan, Russia, and the USA were examined for DNA sequence variation along the whole plastid-encoded RuBisCO cistron: 1406 bp for rbcL, 103 bp for the spacer, and 387 bp for rbcS. C. kondoi specimens were variable, having up to nine haplotypes, with six found in Korea, southern Japan, far-eastern Russia, and the USA, and three found in northern Japan and far-eastern Russia. The occurrence of the same haplotype on both sides of the North Pacific Ocean provides evidence of recent introduction of the species from the west to the east. Phylogenetic reconstructions revealed the monophyly of C. kondoi and two well-supported lineages: a 'southern lineage' that contained specimens from Korea, southern Japan, far-eastern Russia and the USA, and a 'northern lineage' that included specimens from northern Japan and far-eastern Russia. The two genetic lineages are morphologically indistinguishable and referred to as cryptic species. The boundary between the two cryptic species is at the Tsugaru Strait, Japan.
  • Etienne Jean Faye, Kazuhiro Kogame, Satoshi Shimada, Shigeo Kawaguchi, Michio Masuda
    PHYCOLOGICAL RESEARCH 56 2 115 - 126 2008年06月 [査読有り][通常論文]
     
    A new red alga Meristotheca imbricata Faye et Masuda (Solieriaceae, Gigartinales) was described on the basis of specimens collected from southern Japan. Although this species might have been for a long time included in the concept of M. coacta Okamura, until recently a very poorly known alga, it is distinguished from the latter by the following features: (i) each thallus consists of one primary blade and several secondary blades, the latter arising from the apical or subapical portion of terminal segments of the primary blade; (ii) the individual blades are repeatedly dichotomously divided into linear segments of which margins are neither undulate nor crispate, and are fleshy, imbricate, frequently anastomosing and often acervate; (iii) each tetrasporangial initial is attached by a basal pit-connection to the parental cell, and the position of the pit-connection changes from basal to lateral by inward growth of the tetrasporangium; and (iv) the carpogonial branches sometimes have a one-celled sterile lateral.
  • Ga Youn Cho, Kazuhiro Kogame, Hiroshi Kawai, Sung Min Boo
    PHYCOLOGIA 46 6 657 - 665 2007年11月 [査読有り][通常論文]
     
    Sequence variations of the internal transcribed spacers (ITS) 1 and 2 of the nrDNA and the partial RuBisCO large subunit gene-spacer-partial RuBisCO small subunit gene (rbeL-sp-S) region were investigated in samples of Scytosiphon lomentaria (Lyngbye) Link from 50 localities in the Pacific (Australia, Japan, Korea, New Zealand, Russia and United States) and the North Atlantic. ITS1 and ITS2 sequences were determined for 83 samples, the rbcL-sp-S region for 43 samples, and complete rbcL sequences for two European and three Japanese samples. Molecular phylogenetic analyses using rbcL sequences were performed including S. lomentaria and 15 other scytosiphonaccan species. In the rbcL analyses the S. lomentaria samples made a clade consisting of a Pacific and a European subclade. These two subclades also were supported by the ITS and rbeL-sp-S analyses. The nucleotide differences in rbcL were 1.8-2.3% (27-33 bp/1,467 bp) between the two subclades. Such differences are so large that they are considered as indicating different, although cryptic, species. In the ITS analyses the Pacific clade was further divided into two well-supported subclades. In the Pacific clade sample localities were not geographically related to the molecular phylogeny: both subclades included samples from Korea, Japan, Oregon and New Zealand. Artificial translocations are suggested to have occurred because identical sequences were found from localities far from each other, for example, Korea and the United States, the United States and New Zealand. The two Pacific groups are possibly two distinct but cryptic species.
  • Phaik-Eem Lim, Motohiro Sakaguchi, Takeaki Hanyuda, Kazuhiro Kogame, Siew-Moi Phang, Hirosm Kawai
    PHYCOLOGIA 46 4 456 - 466 2007年07月 [査読有り][通常論文]
     
    The order Ralfsiales was established to accommodate the brown algal taxa having a crustose thallus, an isomorphic life history, discoid early development of the thallus and containing a single, plate-shaped chloroplast without pyrenoids in each cell. However, the validity of the order has been questioned by many researchers because several exceptions to these criteria have been found within the order. Molecular phylogenetic analysis of the taxa assigned to the order, using rbcL DNA sequences, reveals that Ralfisiales is not a monophyletic group but is separated into two major groups, excluding Lithodermataceae, which were not included in the present analysis: clade 1, comprising the members of Ralfsiaceae, Mesosporaceae, Analipus japonicus and Heteroralfsia saxicola; and clade 11, consisting of Diplura species, sister to the Ishigeales clade. On the basis of these results, we propose emendment of the Ralfsiales to contain only species having (1) discoidal early development of the thallus; (2) intercalary plurilocular gametangia with terminal cells and terminal unilocular zoidangia; and (3) a crustose phase in the life history. Furthermore, we propose the establishment of the new family Neoralfsiaceae to accommodate the new genus Neoralfsia, on the basis of Ralfsia expansa.
  • Michio Masuda, Akira Kurihara, Kazuhiro Kogame
    PHYCOLOGICAL RESEARCH 55 2 113 - 124 2007年06月 [査読有り][通常論文]
     
    Two species of Dasya in the Dasyaceae (Ceramiales, Rhodophyta) are reported from Bonin Islands, southern Japan. Dasya murrayana Abbott et Millar, new to Japan, is characterized by the following set of features: the tufted habit (up to 30 erect axes developing from a basal disc), small-sized (6-10 mm high and 350-500 mu m in diameter in the middle region), thinly but completely corticated axes, rigid and incurved pseudolaterals forming corymbose heads at the apices of axes and branches, the absence of adventitious monosiphonous filaments, a large number of tetrasporangial stichidia and spermatangial branches per fertile pseudolateral and slender spermatangial branches (35-45 mu m in diameter). Dasya boninensis Masuda, Kurihara et Kogame, sp. nov. is characterized by short but thick (10-30 mm high and 600-1000 mu m in diameter at the middle portion), heavily corticated axes, indistinct pericentral cells except for the upper portion in transverse sections, soft, straight pseudolaterals and adventitious monosiphonous filaments densely covering the axis and branches, a small number of tetrasporangial stichidia and spermatangial branches per fertile pseudolateral, thick spermatangial branches (65-90 mu m in diameter), and short-necked cystocarps. A dichotomous key to the taxa found in Japanese waters is given.
  • Etienne Jean Faye, Kazuhiro Kogame, Satoshi Shimada, Shigeo Kawaguchi, Michio Masuda
    PHYCOLOGICAL RESEARCH 55 2 150 - 158 2007年06月 [査読有り][通常論文]
     
    Vegetative and reproductive structures of the little-known red alga, Meristotheca coacta Okamura (Solieriaceae, Gigartinales) were described on the basis of specimens collected from three localities in southern Japan, including an island close to the lectotype locality. Meristotheca coacta was shown to be a strongly supported monophyletic clade in our rbcL analyses. The taxonomic features of this species were reassessed. This species is characterized as follows: (i) the thalli consist of relatively thick (300-1400 mu m from the uppermost to basal regions), elastic and rose-red blades; (ii) the blades are irregularly lobed and branched into variously shaped segments with undulate and crispate margins; (iii) tetrasporangial initials are laterally attached to their parental cells and the lateral pit-connections remain in mature tetrasporangia; (iv) gametophytes are dioecious; (v) carpogonial branches are three-celled (occasionally two- or four-celled); (vi) a darkly staining auxiliary cell complex is present and recognizable prior to diploidization; and (vii) cystocarps are produced along (or near) the margins of the blades and on the marginal proliferations and lack spinous outgrowths.
  • Y Kato, K Kogame, C Nagasato, T Motomura
    PHYCOLOGICAL RESEARCH 54 1 65 - 71 2006年03月 [査読有り][通常論文]
     
    Patterns of inheritance of chloroplasts and mitochondria were examined by fluorescence microscopy and haplotype genome markers in the isogamous brown alga Scytosiphon lomentaria (Lyngbye) Link. Germination of the zygote in this species was unilateral, the growing thallus developed entirely from the germ tube, and the original zygote cell did not develop except for the formation of a hair. Inheritance of chloroplasts was biparental, and partitioning of the two parental chloroplasts into the first sporophytic cells was accidental: either the maternal or the paternal chloroplast was migrated from the zygote into the germ tube cell, whereas the other chloroplast remained in the original cell. In contrast, the mitochondrial genome in all cells of the sporophyte came only from the female gamete (maternal inheritance). These inheritance patterns are similar to those of the isogamous brown alga Ectocarpus siliculosus (Dillwyn) Lyngbye. Maternal inheritance of mitochondria might be universal in brown algae.
  • Z Perveen, H Ando, A Ueno, Y Ito, Y Yamamoto, Y Yamada, T Takagi, T Kaneko, K Kogame, H Okuyama
    BIOTECHNOLOGY LETTERS 28 3 197 - 202 2006年02月 [査読有り][通常論文]
     
    A thraustochytrid-like microorganism (strain 12B) was isolated from the mangrove area of Okinawa, Japan. On the basis of its ectoplasmic net structure and biflagellate zoospores we determined strain 12B to be a novel member of the phylum Labyrinthulomycota in the kingdom Protoctista. When grown on glucose/seawater at 28 degrees C, it had a lipid content of 58% with docosahexaenoic acid (DHA; 22:6 n-3) at 43% of the total fatty acids. It had a growth rate of 0.38 h(-1). The DHA production rate of 2.8 +/- 0.7 g l(-1)supercript stop day(-1)supercript stop is the highest value reported for any microorganism.
  • S Uwai, N Yotsukura, Y Serisawa, D Muraoka, M Hiraoka, K Kogame
    HYDROBIOLOGIA 553 345 - 356 2006年01月 [査読有り][通常論文]
     
    The intraspecific genetic diversity of the kelp Undaria pinnatifida (Harvey) Suringar (Laminariales, Phaeophyceae) was investigated using DNA sequences of the mitochondrial cytochrome oxidase subunit 3 (cox3) gene and internal transcribed spacer 1 (ITS1) of nuclear ribosomal DNA in plants collected from 21 localities along the Japanese coast between 2001 and 2003. Morphological variation was also examined and compared with the genetic diversity. Cox3 analyses of 106 plants revealed 9 haplotypes (I-IX) that differed from each other by 1-7 bp (all synonymous substitutions). Haplotype I was distributed in Hokkaido and the northern Pacific coast of Honshu, while haplotype III was found along the Sea of Japan coast of Honshu. Other types were found along the central and southern coast of Honshu. ITS1 analyses of 42 plants revealed 0-1.7% nucleotide differences, but plants from the Sea of Japan coast and northern Japan had similar sequences. The lower genetic differentiation along the Sea of Japan and northern coasts might be due to the recent establishment (after the middle of the last glacial period) of the Sea of Japan flora. The cox3 haplotype of cultivated plants was found in natural populations occurring close to cultivation sites (Naruto, Tokushima Pref., and Hokutan, Hyogo Pref.). This suggests that cultivated plants possibly escaped and spread or crossed with plants of natural populations. Morphological analyses of variation in 10 characters were conducted using 66 plants. The results showed no significant local variation owing to the wide variation in each population and did not support any forma previously described. No correlations between the morphological characters and cox3 haplotypes were detected.
  • Molecular phylogeny of the family Scytosiphonaceae (Phaeophyceae)
    Cho, G. Y, Kogame, K, Boo, S. M
    Algae 21 175 - 183 2006年 [査読有り][通常論文]
  • C Camus, AP Meynard, S Faugeron, K Kogame, JA Correa
    JOURNAL OF PHYCOLOGY 41 5 931 - 941 2005年10月 [査読有り][通常論文]
     
    The identity of two phaeophycean taxa that monopolized the middle-lower rocky intertidal zone of a coastal area chronically exposed to copper mine wastes in northern Chile was unraveled. One of them was preliminarily identified as the gametophytic stage of Scytosiphon lomentaria (Lyngbye) Link. The other, a dark crust, resembled the alternate stage of some Scytosiphon species. Comparative analysis of morphology, life history, and DNA sequences strongly suggests that crusts corresponded to sporophytic S. tenellus Kogame and confirm that erect thalli belonged to S. lomentaria. A clear segregation of erect and crustose thalli was found using internal transcribed spacer region 1 and RUBISCO spacer sequences. Furthermore, whereas crusts always grouped with S. tenellus, erect thalli always grouped with S. lomentaria. Life history studies failed to connect the two entities. First, field-collected S. tenellus produced progeny that either recycled the crust, which reproduced by unilocular zoidangia, or developed into erect thalli. The latter, unlike typical gametophytic S. lomentaria, developed patchy sori of plurilocular zoidangia. Second, S. lomentaria displayed a direct-type life cycle, in which progeny from erect individuals only developed into erect thalli and produced only plurilocular zoidangia. This constitutes the first experimental study on Scytosiphon from the Pacific coast of South America and the first report of S. tenellus on this coast. It is also the first report of the crustose stage of Scytosiphon appearing as a perennial and dominant algal species in a temperate rocky intertidal system.
  • K Kogame, S Uwa, S Shimada, M Masuda
    EUROPEAN JOURNAL OF PHYCOLOGY 40 3 313 - 322 2005年08月 [査読有り][通常論文]
     
    The presence or absence of gamete fusion in the dioecious and isogamous brown alga Scytosiphon lomentaria (Scytosiphonaceae, Phaeophyceae) was investigated for thalli collected from three localities, Oshoro, Asari and Muroran in Hokkaido, northern Japan. Both sexual and asexual thalli were found in each locality. These sexual (35 samples) and asexual thalli (15 samples) were used to establish unialgal cultures. ITS2 sequences were determined in all cultures, the rbcL-spacer-S in 14, and cox3 in 25 cultures. Thirteen haplotypes (A1-4, B; C1-4 D E1-3) were found in ITS2 sequences (241-252 bp). Ten haplotypes (A1-4, B, C1-4 and D) were found in sexual samples: haplotypes A and B were found in Oshoro, C and D in Asari, and C in Muroran. Haplotypes E1-3 were found in asexual samples. Sequence divergence values (including gap information) were less than 4.03% among sexual samples (A, B C and D types), 0.38-0.77% among asexual samples (E types) and 4.39-5.70% between sexual and asexual samples. In the mitochondrial cox3 gene region (543 bp), six haplotypes (K 1-3, L, M and N) were obtained. Cox3-K types were found in samples of ITS2-A types, cox3-L type in ITS2-B type, cox3-M type in ITS2-C and D types, and cox3-N type in ITS2-E types. For cox3 sequences, nucleotide differences were 0.18-4.42% among sexual samples (K, L and M types), but 8.66-10.31% between sexual and asexual samples (N type). In partial rbcL (174 bp)-spacer (188 bp)-partial rbcS (90 bp) sequences, six haplotypes (R-W) were found although there were 1-4 bp nucleotide differences among these haplotypes. R, U and W types were found in sexual samples, and S, T and V types in asexual samples. Results of the sequence analyses suggest that our presumed asexual thalli are genetically different from sexual thalli and may be derived from populations that lack sexual reproduction.
  • S Uwai, C Nagasato, T Motomura, K Kogame
    EUROPEAN JOURNAL OF PHYCOLOGY 40 2 179 - 194 2005年05月 [査読有り][通常論文]
     
    A small prostrate filamentous brown alga, isolated from the warm temperate Pacific coast of Japan, was cultured to investigate its life history, morphology, ultrastructure and molecular phylogenetic position. The isolate had an isomorphic, diphasic life history with anisogamous sexual reproduction. Gametogenesis was regulated by temperature and occurred only at temperatures <= 14 degrees C. At higher temperatures, gametophytes reproduced by means of asexual zoids. All swarmers from plurilocular and unilocular zoidangia lacked an eyespot. Both sporophytes and gametophytes had oligostichous filamentous axes, lateral hairs with a basal sheath and no erect thalli. Three to eight oblong chloroplasts, each with a protruding pyrenoid, aggregated to form a stellate chloroplast configuration. All these morphological features suggested that this alga belongs to the genus Asterocladon. Plurilocular gametangia produced in an intercalary or terminal position and zoids lacking eyespots, are, however, unlike those of Asterocladon lobatum, formerly the only member of the genus. Therefore, we described the alga as a new taxon, Asterocladon interjectum sp. nov. Molecular phylogenetic analyses based on the large RUBISCO subunit ( rbcL) and partial SSU nuclear ribosomal RNA gene sequences showed that A. interjectum, A. lobatum and Asteronema rhodochortonoides together formed a monophyletic clade, sister to the Ectocarpales sensu lato. Because the molecular phylogenetic analyses showed Asteronema to be paraphyletic, but monophyly of Asterocladon spp. and Asteronema rhodochortonoides was supported by the absence of cytoplasmic invaginations in pyrenoids, Asteronema rhodochortonoides was transferred to Asterocladon and an emended generic circumscription of Asterocladon was included.
  • EJ Faye, S Shimada, K Kogame, M Masuda
    EUROPEAN JOURNAL OF PHYCOLOGY 40 2 195 - 206 2005年05月 [査読有り][通常論文]
     
    Vegetative and reproductive structures, including the anatomy of young blades, spermatangia, female reproductive organs, post-fertilization development, and tetrasporangia were examined for the little-known red alga, Anatheca montagnei, from Hann Bay, Dakar, Senegal, western Africa, close to the type locality. Carpogonial branches and auxiliary cells develop on cortical filaments in slightly raised nemathecium-like structures. The fertilized carpogonium produces two unbranched, non-septate connecting filaments. The auxiliary cell is one of the intercalary cortical cells, and, together with the surrounding darkly-staining cortical cells, constitutes an auxiliary cell complex that is visible prior to diploidization. The diploidized auxiliary cell cuts off a single gonimoblast initial, which in turn divides to form a placentate cystocarp without distinct enveloping filaments. The cystocarps are contained in cystocarpic protuberances or papillae that are situated on the surfaces and margins of the female blade. Tetrasporangia are cut off laterally from their parental cells and are zonately divided. The alga is characterized by the above-mentioned combination of features but its position within the Solieriaceae was not demonstrated by our rbcL analyses.
  • EJ Faye, S Shimada, K Kogame, M Masuda
    CRYPTOGAMIE ALGOLOGIE 25 3 241 - 259 2004年07月 [査読有り][通常論文]
     
    The marine red alga Meristotheca dakarensis Faye et Masuda, sp. nov. (Solieriaceae, Gigartinales) is described on the basis of material collected at Dakar, Senegal, western Africa and distinguished from other members of the genus by the following combination of morphological features: 1) irregularly dichotomously branched, thick, fleshy, tough, decumbent blades 10-30 cm in length and 500-1200 mum in thickness, with segments 1-4 cm in width; 2) tetrasporangial initials cut off basally from their parental cells; 3) dioecious gametophytes; 4) (2-)3(-4)-celled carpogonial branches, the basal cell of which rarely bears a single lateral cell; 5) the presence of an auxiliary-cell complex; and 6) the production of numerous protuberant cystocarps on the dorsal surfaces (less frequently on the ventral surfaces and margins) of the mid to distal portions of the blades. Molecular-phylogenetic analyses based on rbcL gene sequences indicate that Meristotheca dakarensis is contained within a monophyletic clade that includes species currently placed in either Meristiella and Meristotheca, the clade becoming paraphyletic with the recognition of both genera. Pairwise distances between M. dakarensis and other species of he genus complex are large, ranging from 44 bp to 64 bp (4.3% to 5.1%). Anatomical features previously used to distinguish Meristiella Cheney from Meristotheca I Agardh (the absence of carpogonial nemathecia; the presence of an auxiliary-cell complex; cystocarps that bear conspicuous spines) are shown to be inconsistently displayed among species of the clade, and it is proposed as a result of both morphological and molecular data that Meristiella be subsumed in Meristotheca, the necessary new combinations being made as a consequence.
  • M Masuda, S Uwai, K Kogame, S Kawaguchi, SM Phang
    BOTANICA MARINA 46 3 243 - 255 2003年05月 [査読有り][通常論文]
     
    Four species of the red algal genus Dasya (Dasyaceae,Ceramiales), including two new species, are reported from Malaysia. Dasya iyengarii Borgesen and D. pilosa (Weber-van Bosse) Millar are reported from Malaysia for the first time, and their morphological features are described along with taxonomic comments. Dasya longifila Masuda et Uwai, sp. nov. is chiefly distinguished by its long, monosiphonous, pseudolateral filaments (often longer than the axis) in which intercalary cell divisions take place, and a small number of tetrasporangial stichidia and spermatangial branches per fertile pseudolateral from several related species that possess small-statured, sparsely corticated axes.Dasya malaccensis Masuda et Uwai,sp.nov. is characterised by its diminutive thallus (up to 10 mm high) with thickly corticated axes, relatively short pseudolaterals, and narrow tetrasporangial stichidia and spermatangial branches. This species has no close relatives among small-sized species of Dasya.
  • Y Yamagishi, M Masuda, T Abe, S Uwai, K Kogame, S Kawaguchi, SM Phang
    BOTANICA MARINA 46 6 534 - 547 2003年 [査読有り][通常論文]
     
    Hypnea cornuta (Kutzing) J. Agardh var. stellulifera J. Agardh (Hypneaceae, Gigartinales) is distinguished from the type variety by the short, thick, rigid axes that produce thick adventitious branchlets as well as the tetrasporangial sori and spermatangial sori that extend to the parental axis and branches. Var. stellulifera is raised to the rank of species as Hypnea stellulifera (J. Agardh) Yamagishi et Masuda on the basis of these morphological differences and comparative chloroplastencoded rbcL sequences. Reproductive structures of Heterosiphonia crispella (C. Agardh) Wynne (Dasyaceae, Ceramiales), which is referable to var. laxa (Borgesen) Wynne, are described. Two species of Laurencia (Rhodomelaceae, Ceramiales) are reported from Malaysia for the first time: L. pygmaea Webervan Bosse and L. majuscula (Harvey) Lucas. Critical features of L. pygmaea include four pericentral cells per segment, the presence of a single (rarely two) corps en cerise per superficial cortical cell, and the production of a single tetrasporangiumbearing pericentral cell on each fertile segment.
  • M Tani, Y Yamagishi, M Masuda, K Kogame, S Kawaguchi, SM Phang
    BOTANICA MARINA 46 1 24 - 35 2003年01月 [査読有り][通常論文]
     
    Three species of marine red algae are reported from Malaysia for the first time and their morphological features are described along with taxonomic comments. Hypnea charoides Lamouroux (Hypneaceae, Gigartinales) represents a geographic record intermediate between the Australian type locality and the Japanese islands in the Pacific Ocean. Hypnea flexicaulis Yamagishi et Masuda is reported for the first time outside Japan. Polysiphonia apiculata Hollenberg (Rhodomelaceae, Ceramiales) is transferred to Neosiphonia, as N. apiculata (Hollenberg) Masuda et Kogame, comb. nov. Furthermore, a minute-statured new species of Chondria (Rhodomelaceae), C decidua Tani et Masuda, is described for an alga that is primarily distinguished from morphologically similar species by its production of small deciduous branchlets, which may function as propagules.
  • M Masuda, T Abe, K Kogame, S Kawaguchi, SM Phang, M Daitoh, T Sakai, M Takahashi, M Suzuki
    BOTANICA MARINA 45 6 571 - 579 2002年11月 [査読有り][通常論文]
     
    Three species of the red algal genus Laurencia (Ceramiales, Rhodomelaceae) are reported from Malaysia for the first time: L. lageniformis Masuda, L. nangii Masuda and L. calliclada Masuda. Some morphological features regarding corps en cerise and spermatangial branches, which have been unknown for these species, are described. The occurrence of plural corps en cerise in individual trichoblast cells of L. nangii is the first report for the species of Laurencia, as some species have been reported to possess two to four (or more) corps en cerise in superficial cortical cells, but such species are known to contain only a single corps en cerise in trichoblast cells. Furthermore, halogenated secondary metabolite contents of these species are reported.
  • S Kawaguchi, A Kato, M Masuda, K Kogame, SM Phang
    BOTANICA MARINA 45 6 536 - 547 2002年11月 [査読有り][通常論文]
     
    The presence of three species of Halymenia (Halymeniaceae), H. durvillei Bory de Saint-Vincent, H. dilatata Zanardini and H. maculata J. Agardh in Malaysia is confirmed by their gross morphology and anatomical features. The reproductive details of H. durvillei including the Halymenia-type auxiliary-cell ampullae are described for the first time. Peyssonnelia inamoena Pilger (Peyssonneliaceae) is reported from Malaysia for the first time, and its monoecious gametophytes and its P. harveyana-type spermatangial development are confirmed. A small-statured new species of Lomentaria (Lomentariaceae), L. gracillima Masuda ct Kogame, is described on the basis of such characteristic features as very short and slender axes (up to 8 mm long by 200-250 mum wide) and the production of tetrasporangial sori in fairly wide regions of ascending axes and erect branches: the subapical or middle portions of the axes; and the proximal to middle portions of the branches.
  • Shinya Uwai, Kazuhiro Kogame, Michio Masuda
    Phycological Research 50 3 217 - 225 2002年 [査読無し][通常論文]
     
    A taxonomic study of two brown algal species, Elachista nigra Takamatsu and Elachista orbicularis (Ohta) Skinner (Elachistaceae), was performed on the basis of morphological observations of field-collected and laboratory cultured specimens from Japan (including their type localities) and molecular phylogenetic analyses. The two species had been distinguished by developmental patterns of paraphysis- and plurizoidangium-bearing erect filaments, such filaments of E. nigra developing from wide erect filaments and those of E. orbicularis developing directly from basal prostrate filaments. However, many specimens investigated in the present study showed forms intermediate between these two patterns. Molecular phylogenetic analyses (including five additional elachistacean species) based on the internal transcribed spacer (ITS)2 region of the nuclear ribosomal RNA (nrRNA) gene showed a close relationship between all samples of E. nigra and E. orbicularis, and that the developmental patterns of paraphysis- and plurizoidangium-bearing erect filaments were homoplasious. On the basis of these morphological and molecular data, E. orbicularis was reduced to synonymy with E. nigra. The ITS2 sequences of E. nigra were significantly different between samples from the Sea of Japan and those from the Pacific Ocean with several insertion/deletion and substitution mutations.
  • S Uwai, K Kogame, M Masuda
    EUROPEAN JOURNAL OF PHYCOLOGY 36 2 103 - 111 2001年05月 [査読有り][通常論文]
     
    The taxonomic status of three closely related species of the brown algal genus Elachista, E, tenuis Yamada, E. sargassicola Noda and E. nipponica Umezaki (Elachistaceae, Ectocarpales sensu Into) was reassessed on the basis of morphological observations including laboratory culture experiments and molecular phylogenetic analyses. These species share characteristic assimilatory filaments of constant width throughout their length except for slightly constricted bases and slightly tapering apices. Although E. sargassicola has been characterized by the presence of phaeophycean hairs, our culture experiments revealed that the presence or absence of such hairs is not a stable taxonomic feature in E. tenuis and E. sargassicola. Furthermore, molecular analyses showed that the rRNA ITS1 and ITS2 regions of E. tenuis and E. sargassicola were nearly identical and grouped them in a strongly supported monophyletic clade. Thus, E. sargassicola should be reduced to synonymy with E. tenuis. On the other hand, E, nipponica, which has been characterized by the production of cylindrical cells in a basal hemispherical cushion, formed cylindrical cells under experimental culture conditions, indicating that the production of such cells is a specific feature of E. nipponica. However, another reported feature of E. nipponica, the production of intercalary plurizoidangia in assimilatory filaments, was rejected, because reexamination of type material revealed that filaments bearing such reproductive structures are referable to Leptonematella fasciculata (Reinke) Silva. Molecular phylogenetic analyses support the distinction of E. tenuis and E. nipponica.
  • K Kogame, M Masuda
    CRYPTOGAMIE ALGOLOGIE 22 2 201 - 208 2001年04月 [査読有り][通常論文]
     
    Crustose sporophytes of Colpomenia bullosa (Saunders) Yamada (Scytosiphonaceae, Phaeophyceae) were collected in Oshoro and Muroran, Hokkaido, Japan, and identified by laboratory cultivation and DNA sequences of the Rubisco spacer and the internal transcribed spacer 2 (ITS2) region of the nuclear ribosomal DNA cistron. The sporophyte morphology of C. bullosa is characteristic, with crustose thalli consisting of upwardly and downwardly curved branched filaments, unilocular zoidangia lateral on the bases of the paraphyses, and clavate ascocysts among the paraphyses. This study is the first to describe in detail these crustose brown algae. (C) 2001 Adac/Editions scientifiques et medicales Elsevier SAS.
  • Phylogeny of the family Scytosiphonaceae (Phaeophyta) from Korea based on sequences of plastid-encoded RuBisCo spacer region
    Ga Youn Cho, Hwan Su Yoon, Han-Gu Choi, Kazuhiro Kogame, Sung Min Boo
    Algae 16 145 - 150 2001年 [査読有り][通常論文]
  • S Uwai, K Kogame, M Masuda
    PHYCOLOGIA 40 1 67 - 77 2001年01月 [査読有り][通常論文]
     
    Three brown algae, Elachista taeniaeformis. Elachista flaccida and Myriactula clavata, which seem to resemble one another in many features and constitute a complex that we call the E. taeniaeformis complex, have been distinguished in the western Pacific by the degree of tapering of the assimilatory filaments, the presence or absence of phaeophycean hairs, and the presence or absence of paraphyses. Morphological observations and laboratory culture experiments based on collections from various localities in Japan indicated that these morphological characters vary, depending on the growing season, experimental culture conditions and age. Molecular-phylogenetic analyses of these and four other elachistacean species, based on ITS regions of the nrRNA gene, showed a close relationship between all samples of the three taxa. Morphological and molecular data indicate that only a single species, E. taeniaeformis, is present within the complex and that genuine E. flaccida should be excluded from the western Pacific marine algal flora. Myriactula clavata is synonymized with E, taeniaeformis, as is Elachista sadoensis. Elachista vellosa is closely related to E. taeniaeformis in the molecular-phylogenetic analyses but is distinguished from it morphologically by having slightly tapering assimilatory filaments with gradually constricted bases.
  • M Masuda, K Kogame, S Kawaguchi, SM Phang
    BOTANICA MARINA 44 1 81 - 88 2001年01月 [査読有り][通常論文]
     
    Five species of the red algal order Rhodymeniales are reported from Malaysia for the first time and their characteristic features are described: Chamaebotrys boergesenii (Weber-van Bosse) Huisman (Rhodymeniaceae), Coelarthrum sp. (Rhodymeniaceae), two species of Champia (Champiaceae), C. compressa Harvey and C. vieillardii Kutzing, and Lomentaria monochlamydea (J. Agardh) Kylin (Lomentariaceae). The alga with vegetative features similar to the Chamaebotrys/Coelarthrum group is new to science and is characterised by the presence of a conspicuously developed, solid, cartilaginous stipe. This alga seems to be more closely related to Coelarthrum on the basis of its upright habit rather than Chamaebotrys, which has decumbent or prostrate thalli. The production of slender branches in Champia vieillardii is an additional critical feature that distinguishes it from a closely related species, C. compressa.
  • K. Kogame
    Phycological Research 49 2 123 - 128 2001年 [査読無し][通常論文]
     
    The life history of the brown alga Chnoospora implexa J. Agardh (Chnoosporaceae, Scytosiphonales) from Japan was studied in laboratory cultures. This species showed a heteromorphic and diphasic life history, alternating between erect gametophytes and discoid sporophytes. The gametophytes were dioecious and produced isogametes. The zygotes developed into sporophytes at 20°C under long-day conditions, which formed plurilocular zoidangia. Zoids released from the plurilocular zoidangia developed again into sporophytes that always formed plurilocular zoidangia at 20°C and 25°C in long-day conditions, and mainly unilocular zoidangia at 25°C in short-day conditions. Zoids released from unilocular zoidangia developed into dioecious gametophytes. At 15°C zygotic erect thalli were formed and were revealed to be diploid by microspectrofluorometric measurements of nuclear DNA contents. The development and reproduction of unfused gametes were similar to those of zygotes. Some strains showed a direct-type life history gametophytic thalli were produced, but not via a sporophytic phase.
  • Kazuhiro Kogame, Shinya Uwai, Shigeo Kawaguchi
    Phycological Research 49 4 281 - 284 2001年 [査読無し][通常論文]
     
    Morphological observations of a minute, filamentous, branched brown alga epiphytic on Sargassum thunbergii (Mertens ex Roth) Kuntze were made on material collected at Tsuyazaki (33°48′N, 130°27′E), Fukuoka Prefecture, southern Japan. This alga was assignable to Asteronema rhodochortonoides (Børgesen) Müller et Parodi in having stellately arranged chloroplasts with several pyrenoids grouped in the center, predominantly apical growth, narrow filaments, and elliptical or broadly elliptical plurilocular zoidangia that are apically or laterally formed on upright filaments. A comparison of partial nuclear small subunit rDNA sequences between the Japanese material and A. rhodochortonoides from the Canary Islands showed only two or three nucleotide differences. This supports our assignment of the Japanese material to this species as a first report for the Pacific Ocean. In laboratory cultures, zoids released from plurilocular zoidangia developed into plants with morphology similar to the field-collected plants. This cycle repeated without production of unilocular zoidangia in our cultures.
  • M Masuda, K Kogame, S Kawaguchi, SM Phang
    BOTANICA MARINA 43 6 569 - 579 2000年11月 [査読有り][通常論文]
     
    The following five species of marine red algae are reported from Malaysia for the first time and their characteristic features are described: two species of Martensia (Delesseriaceae, Ceramiales), M. australis Harvey and M. fragilis Harvey, two species of Herposiphonia (Rhodomelaceae, Ceramiales), H. pacifica Hollenberg and H. vietnamica Pham, and Neosiphonia flaccidissima (Hollenberg) M. S. Kim ct I. K. Lee (Rhodomelaceae, Ceramiales). The presence of Polysiphonia scopulorum Harvey in Malaysia is confirmed.
  • M Masuda, K Kogame
    CRYPTOGAMIE ALGOLOGIE 21 2 177 - 189 2000年04月 [査読有り][通常論文]
     
    Two species of the red algal genus Herposiphonia (Ceramiales, Rhodomelaceae) are described on the basis of material collected from Malaysia in the western Pacific: Herposiphonia elongata Masuda et Kogame, sp. nov. and H. tenella (C. Agardh) Ambronn. In H. elongata a single procarpial trichoblast is produced on the subterminal segment of each fertile determinate branch, which ceases apical growth as a cystocarp develops (hence, the cystocarp is terminal on the branch), whereas in H. tenella one to three procarpial trichoblasts are formed on the distal segments of each fertile determinate branch, which grows upwards and forms an additional seven to 12 segments when it has a developing cystocarp (hence, the cystocarp is median on the branch). Cystocarp-bearing branches of the two species become conspicuously thickened as the cystocarp develops. Spermatangial branches of both species are formed on the distal successive several (three or four in H. elongata and four to six in H. tenella) segments in a spiral manner and have either an extremely elongated sterile tip (five to seven cells and 500-900 mu m long) in H. elongata or a short one- or sometimes two-celled sterile tip (15-25 mu m long) in H. tenella. The new species H. elongata is clearly distinguished from previously described species of this genus by such spermatangial branches. (C) 2000 Adac/Editions scientifiques et medicales Elsevier SAS.
  • S. Uwai, K. Kogame, M. Masuda
    Phycological Research 48 4 267 - 279 2000年 [査読無し][通常論文]
     
    Elachista fucicola (Velley) Areschoug (Elachistaceae, Phaeophyceae) is newly recorded from Japan, and compared with three previously described species, Elachista coccophorae Takamatsu, Elachista mollis Takamatsu and Elachista okamurae Yoshida. All species showed direct-type life histories in culture without sexual fusion. Prostrate filaments of E. fucicola formed globular plurilocular zoidangia similar to those reported from Atlantic isolates of this species. However, these were different from uniseriate plurilocular zoidangia of the three Japanese species. Furthermore, the position of a meristematic region in assimilatory filaments and the morphology of paraphyses can easily distinguish these from E. fucicola. Previously emphasized differences in cell length: width ratios in assimilatory filaments showed only slight differences. Elachista coccophorae is characterized by thick-walled assimilatory filaments and curved paraphyses, and the absence of downwardly growing rhizoidal filaments. Elachista mollis and E. okamurae are very similar. However, germlings from plurizoids formed on erect filaments of E. mollis showed characteristic pseudodiscoid growth in culture. Halothrix coccophorae Ohta and Elachista zosterae Noda are reduced to synonyms of E. coccophorae and E. mollis, respectively.
  • K Kogame, T Horiguchi, M Masuda
    PHYCOLOGIA 38 6 496 - 502 1999年11月 [査読有り][通常論文]
     
    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.
  • M Masuda, K Kogame
    CRYPTOGAMIE ALGOLOGIE 19 3 201 - 212 1998年08月 [査読有り][通常論文]
     
    The red alga Laurencia concreta Cribb (Rhodomelaceae, Ceramiales), reported for the first time from Vietnam, is characterised by the production of two vegetative periaxial cells from each axial segment. This, in combination with other features, confirms its inclusion in the subgenus Chondrophycus. Laurencia dinhii Masuda et Kogame, sp. nov., endemic to southern Vietnam, is characterised by the following set of morphological features: 1) a basal system composed of a single disc from which a few terete to subterete axes arise; 2) the production of two vegetative periaxial cells from each axial segment; 3) the presence of a palisade-like superficial cortical layer, 3) the absence of projecting superficial cortical cells; 5) the absence of longitudinally oriented secondary pit-connections between contiguous superficial cortical cells; 6) the absence of lenticular thickenings in the walls of medullary cells; 7) the presence of intercellular spaces between contiguous medullary cells; 8) a perpendicular arrangement of tetrasporangia, each of which is produced from the second periaxial cell in each fertile segment; 9) procarps produced from the last-formed (fourth) periaxial cell of the terminal segment of a two-celled female trichoblast; and 10) flask-shaped cystocarps.
  • M Masuda, K Kogame
    EUROPEAN JOURNAL OF PHYCOLOGY 33 2 139 - 147 1998年05月 [査読有り][通常論文]
     
    The marine red alga Ahnfeltiopsis friquetrifolia sp. nov. (Phyllophoraceae, Gigartinales) is described from Japan. Foliaceous unisexual gametophytes are characterized by having three-edged axes, and crustose tetrasporophytes are distinguished by the following combination of features: tightly coalescent perithallial filaments, nemathecial sori, small numbers of both tetrasporangia (3 or 4) and sterile cap cells (1 or 2) in each fertile filament, and the absence of hypobasal tissue. Gonimoblast filaments develop from the auxiliary cell after it has fused with a carpogonium. Carposporangia develop from gonimoblast cells, from medullary cells contacted by the gonimoblast filaments, and from the cells produced by such medullary cells. Mature, compact cystocarps are immersed within the medullary layer and discharge carpospores through carpostomes formed in the thickened cortex. Cultured tetrasporophytes were induced to sporulate by transfer from a long-day to a short-day regime at 20 degrees C, and one single short-day cycle was effective for tetrasporangial induction. Tetraspore germlings gave rise to basal discs from which upright axes developed. The upright axes showed a morphology similar to that of field-collected gametophytes, although they remained vegetative during 18 months in culture.
  • K Kogame, H Horiuchi, T Yoshida, M Masuda
    BOTANICA MARINA 41 3 339 - 344 1998年05月 [査読有り][通常論文]
     
    Taxonomic features of the brown alga Analipus gunjii (Yendo) Kogame et Yoshida are reported on the basis of material from northern Japan. This species is clearly distinguished from other species of the genus Analipus by its discoid basal systems. Plants are dioecious, and gametes are weakly anisogamous. This species is perennial, showing an apparent seasonality at Oshoro, Hokkaido. Erect axes arise from basal systems in October and persist until March, and only discoid basal systems are present from April to September. In culture, basal systems became discoid under all culture conditions examined (5-20 degrees C in short and long days). More abundant production of erect axes occurred under short-day culture conditions than long-day ones.
  • M Masuda, K Kogame, S Arisawa, M Suzuki
    BOTANICA MARINA 41 3 265 - 277 1998年05月 [査読有り][通常論文]
     
    Laurencia majuscula (Harvey) Lucas is characterised by the production of four periaxial cells from each vegetative axial segment and of two tetrasporangium-bearing (the third and fourth) periaxial cells per fertile segment in tetrasporangial branches, in addition to other features. Major halogenated secondary metabolites of this species are sesquiterpenoids, isoobtusol and elatol. Laurencia intricata Lamouroux is characterised by the presence of 2-4 corps en cerise per superficial cortical cell, in addition to other features. A major halogenated compound of this alga is a sesquiterpenoid, caespitol. Laurencia perforata (Bory) Montagne is characterised by the production of two periaxial cells from each vegetative axial segment, tetrasporangia formed on two (the second and additional third) periaxial cells from each axial segment in tetrasporangial branches, and the absence of corps en cerise, in addition to other features. Halogenated secondary metabolites were not detected in this alga, although some characteristic sesquiterpenoids have been reported from material collected from Fuerteventura, the Canary Islands. This strongly suggests that the Fuerteventuran alga was not properly identified.
  • M Masuda, K Kogame
    BOTANICA MARINA 41 3 243 - 247 1998年05月 [査読有り][通常論文]
     
    Hawaiian and Japanese populations of the red alga Ahnfeltiopsis concinna (J. Agardh) Silva et DeCew (Phyllophoraceae, Gigartinales) were examined on the basis of cultured plants. Reported differences between Hawaiian and Japanese plants in two taxonomically significant reproductive features, the absence or presence of a sterile lateral on the carpogonial branch and the non-nemathecial or nemathecial tetrasporangial sorus, were not found. Plants of both populations formed procarps, each of which consisted of a large supporting cell and a three-celled carpogonial branch (carpogonium, hypogynous cell, and basal cell) with a one-celled sterile lateral from the basal cell, and nemathecial tetrasporangial sori. Furthermore, no morphological differences between cultured plants of the Hawaiian and Japanese populations were found. All attempted crosses were positive, with carpospores from the cross developing into fertile F-1 tetrasporophytes releasing tetraspores that developed into dioecious F-1 gametophytes, the female gametophytes of which formed normal cystocarps, indicating that interbreeding is potentially free among the populations studied. It is concluded that the Hawaiian and Japanese plants are referred to as a single species that shows remarkable variability in gross morphology which may be caused by growth stages and different environments.
  • Y Yamagishi, K Kogame
    BOTANICA MARINA 41 2 217 - 222 1998年03月 [査読有り][通常論文]
     
    The ratio of fertile male to female gametophytes of Colpomenia peregrina (Sauvageau) Hamel (Scytosiphonales, Phaeophyceae) was investigated through its reproductive season at Oshoro in Hokkaido, Japan. It was about 1:19 in the samples examined with determination by the size of gametangia. Thirty-three culture strains were established from sporophytic discoid thalli collected from the field. Both female and male gametophytes appeared in 10 strains of these cultures, and only female gametophytes appeared in the remaining 23 strains. However, there was no strain in which only male gametophytes appeared in culture. These 10 strains and 23 strains were considered to be derived from zygotic sporophytes and female parthenosporophytes, respectively. Germination of unfused female and unfused male gametes was examined in culture. The ability for germination was much lower in male gametes than that in female gametes. Although, the cause of the female dominance of this species at Oshoro was discussed considering the presence or absence of female-like, asexual plants, the female dominance is chiefly due to the frequent occurrence of parthenogenesis of female gametes.
  • M Masuda, K Kogame, T Abe, S Kamura
    BOTANICA MARINA 41 2 133 - 140 1998年03月 [査読有り][通常論文]
     
    The red alga Laurencia palisada Yamada (Rhodomelaceae, Ceramiales), the lectotype species of the section Palisadae, is characterised by the following set of features: 1) rigidly cartilaginous upright axes arising from a discoid holdfast; 2) a shift of branching from a distichous to a spiral manner distally; 3) the production of two periaxial cells per vegetative axial segment; 4) the absence of longitudinally oriented secondary pit-connections between cintiguous superficial cortical cells; 5) the absence of projecting superficial cortical cells; 6) the presence of a palisade-like cortical layer; 7) the absence of lenticular thickenings in the walls of medullary cells; 8) the absence of corps en cerise in any cell; 9) the production of two tetrasporangium-bearing periaxial cells from each fertile segment; 10) a perpendicular arrangement of tetrasporangia; 11) procarps produced from the last-formed (fourth) peraxial cell of the terminal segment of a two-celled female trichoblast; 12) flask-shaped cystocarps; and 13) distally positioned spermatangial nuclei.
  • Kazuhiro Kogame
    Phycological Research 46 1 39 - 56 1998年 [査読無し][通常論文]
     
    Morphological and culture studies were carried out on the genus Scytosiphon (Scytosiphonales, Phaeophyceae) growing in Japan. Morphologies of plurilocular zoidangia and sporophytic thalli were found to be useful as taxonomic characters. Two types of plurilocular zoidangial sori were recognized: (i) loosely coherent plurilocular zoidangia without a cuticular layer (loose type) (ii) tightly coherent plurilocular zoidangia with a cuticular layer (coherent type). The sporophytic thallus morphology was different among species in general appearance (tufted or discoid), degree of cohesion of erect filaments, and presence or absence of paraphyses. Two new species are described, Scytosiphon gracilis sp. nov. and Scytosiphon tenellus sp. nov. Scytosiphon gracilis is distinguished from other species by a thin medullary layer, coherent plurilocular zoidangia, no ascocysts associated with plurilocular zoidangia, and Compsonema-like sporophytic thalli. Scytosiphon tenellus is characterized by a thin medullary layer, coherent plurilocular zoidangia, ascocysts among plurilocular zoidangial sori, and Stragularia-like sporophytic thalli. Scytosiphon lomentaria (Lyngbye) Link is characterized by a constricted gametophytic thallus, loose plurilocular zoidangia, the presence of ascocysts, and sporophytic thalli identified with Microspongium gelatinosum Reinke.
  • Michio Masuda, Kazuhiro Kogame
    Phycological Research 46 1 29 - 37 1998年 [査読無し][通常論文]
     
    The red alga Neorhodomela enomotoi Masuda et Kogame (Rhodomelaceae, Ceramiales) is described as a new species from Japan. It is characterized by the following combination of features: (i) thalli reddish-brown and slightly rigid (ii) first-order branches mostly indeterminately branched (iii) adventitious branches infrequent, determinately branched and formed chiefly in the axils of lateral branches (iv) vegetative trichoblasts abundant (v) tetrasporangia produced on paniculate ultimate and penultimate branches and (vi) cystocarps flask-shaped (urceolate). This species has been found growing only in the upper subtidal zone in the warm temperate waters of Japan.
  • Michio Masuda, Kazuhiro Kogame, Shintoku Kamura
    Phycological Research 46 2 85 - 90 1998年 [査読無し][通常論文]
     
    The marine red alga Laurencia mariannensis Yamada (Rhodomelaceae, Ceramiales) is characterized by pale rose-red, softly fleshy, slender, terete axes (up to 600 μm in diameter), arising from a loosely entangled, stoloniferous basal system among species that have the following combination of features: the presence of longitudinally orientated secondary pit-connections between contiguous superficial cortical cells the presence of projecting superficial cortical cells at the upper portions of branches and the presence of lenticular thickenings in the walls of medullary cells. Furthermore, the presence of two or three corps en cerise per superficial cortical cell and one per trichoblast cell may characterize the species.
  • Michio Masuda, Shinya Uwai, Kazuhiro Kogame
    Phycological Research 46 4 239 - 251 1998年 [査読無し][通常論文]
     
    Material of the red alga Odonthalia floccosa (Esper) Falkenberg (Rhodomelaceae, Ceramiales), collected from California, was cultured in the laboratory and its life-history was completed. Tetraspores grew into bipolar sporelings that differentiated into a colorless rhizoidal portion and a pigmented upright shoot. The sporelings became compressed apically and formed lateral branches in a regularly distichous manner that were congenitally fused with the main axis. These tetraspore germlings grew into diecious gametophytes. Male gametophytes produced numerous spermatangia on modified fertile branchlets (male trichoblasts) that possessed three to four monosiphonous, proximal segments. Female gametophytes formed a single procarp on the suprabasal segment of unbranched female trichoblasts. Cystocarps developed on the female gametophytes cocultured with male gametophytes and released viable carpospores that developed into fertile tetrasporophytes. Tetrasporangia were produced from the third and fourth periaxial cells in each of 12-45 successive fertile segments and provided three (two lateral and one basal) cover cells. The occurrence of both spermatangia and procarps on fertile trichoblasts in O. floccosa suggests that the alga is the most derived in these two characters among the species of the genus Odonthalia. This species is distributed in cold temperate regions in the North Pacific, and it should be excluded from the North Atlantic marine algal flora.
  • M Masuda, K Kogame, T Abe, S Kamura
    CRYPTOGAMIE ALGOLOGIE 18 4 319 - 329 1997年11月 [査読有り][通常論文]
     
    The red alga Laurencia parvipapillata Tseng (Rhodomelaceae, Ceramiales) is characterised by the following set of features: 1) decumbent or prostrate thalli with conspicuously dorsiventral organisation; 2) distichous branching; 3) the production of two periaxial cells from each vegetative axial segment; 4) the sporadic occurrence of longitudinally and laterally oriented secondary pit-connections between contiguous superficial cortical cells; 5) the presence of projecting superficial cortical cells; 6) the presence of a palisade-like cortical layer; 7) the absence of lenticular thickenings in the walls of medullary cells; 8) the absence of corps en cerise; 9) a perpendicular arrangement of tetrasporangia; 10) the production of three tetrasporangium-bearing (an ordinary and two additional, the second to fourth) periaxial cells per fertile segment of tetrasporangial branches; and 11) spermatangia with distally-positioned nuclei.
  • Kazuhiro Kogame, Yukimasa Yamagishi
    PHYCOLOGIA 36 5 337 - 344 1997年09月 [査読有り][通常論文]
     
    Life-history studies on Colpomenia peregrina (Sauvageau) Hamel from Hokkaido, Japan, were carried out in field and culture. In the field, minute gametophytes appeared in late autumn, were fertile from late winter until early summer, and disappeared from mid-summer onward. Sporophytes were found from spring to autumn, bearing ectocarpoid plurilocular sporangia during spring and summer and unilocular sporangia in autumn. Fertile sporophytes were minute and discoid, 1-3 mm in diameter, epilithic or epiphytic, consisting of prostrate and erect filaments, and bearing ascocysts. In culture, zygotes and unfused gametes developed into prostrate sporophytes that were similar in morphology to field-collected sporophytes. These sporophytes produced plurilocular sporangia at 5-20 degrees C, mainly in long-day photoperiods, and unilocular sporangia mainly at 15 and 20 degrees C, both in short days. Spores released from plurilocular sporangia on the sporophytes developed again into sporophytes; however, unispores developed into saccate gametophytes. In cultures from field sporophytes, saccate thalli identical with C. peregrina were obtained. Seasonality of gametophytes of C. peregrina can be explained by photoperiodic and temperature responses in sporangial production of sporophytes.
  • Kazuhiro Kogame
    PHYCOLOGIA 36 5 389 - 394 1997年09月 [査読有り][通常論文]
     
    The life history of Petalonia fascia (O.F Muller) O. Kuntze (Scytosiphonales, Phaeophyceae) was studied in cultures originating from sexual material from northern Japan. Gametophytes are dioecious, and gametes are isogamous. The life history pattern agreed with that widely known in the family Scytosiphonaceae: a heteromorphic and diphasic alternation between erect gametophytes bearing plurilocular gametangia and discoid sporophytes bearing unilocular sporangia. Zygotes developed into sporophytes, and unispores developed into gametophytes. Erect blades were rarely formed on zygotic sporophytes. Unfused gametes developed into parthenogenetic sporophytes, which sometimes formed erect blades. Unilocular sporangia were formed only at 20 degrees C in short-day conditions. The field-collected sporophytes were morphologically similar to Ralfsia californica Setchell et Gardner and Stragularia clavata (Harvey) Hamel. Unispores from the field-collected sporophytes developed in culture into gametophytic blades identical to P. fascia.
  • Kazuhiro Kogame
    Phycological Research 45 4 227 - 231 1997年 [査読無し][通常論文]
     
    Life-history studies in culture were carried out on Colpomenia sinuosa (Mertens ex Roth) Derbès et Solier and Hydroclathrus clathratus (C. Agardh) Howe (Scytosiphonales, Phaeophyceae) from Japan. These species showed a heteromorphic life-history pattern with an alternation between erect thalli bearing plurilocular zoidangia and prostrate thalli bearing ectocarpoid plurilocular and unilocular zoidangia. Plurizoids released from erect and prostrate thalli developed into prostrate thalli. Unizoids, however, developed into erect thalli. Prostrate thalli produced plurilocular zoidangia in long-day conditions and unilocular zoidangia in short-day conditions at 10-20°C. Prostrate thalli of C. sinuosa formed ascocysts. Germlings of both species did not grow at 5°C.
  • Michio Masuda, Tetsu Shimizu, Kazuhiro Kogame
    Phycological Research 45 4 197 - 206 1997年 [査読無し][通常論文]
     
    The life history of the red alga Ahnfeltiopsis paradoxa (Suringar) Masuda (Phyllophoraceae, Gigartinales) from Japan was completed in laboratory culture. Carpospores isolated from field-collected plants germinated to form circular crusts that were composed of a monostromatic hypothallium consisting of radiating filaments, a polystromatic perithallium consisting of tightly coalescent erect filaments, and hypobasal tissue derived from the hypothallium. The crusts were induced to sporulate by transferring them from short-day to long-day regimes at 15° and 20°C. Each crust produced several nemathecia along 1-4 concentric rings. Intercalary, cruciately or decussately divided tetrasporangia were formed in 4-6 (1-2 at the margin of the nemathecium) successive cells of a single filament of the nemathecia. Tetraspore germlings gave rise to basal discs from which upright axes developed. The upright axes first grew without branches or were sparsely branched and later bore many marginal reproductive proliferations. Procarps and spermatangia were formed in the proliferations on different individuals. Carposporophytes developed on female plants that were co-cultured with male plants. Gonimoblast filaments were formed from an auxiliary cell that fused with a carpogonium. Carposporangia developed from gonimoblast filaments and medullary cells contacted by the gonimoblast filaments. Carpospores were discharged through carpostomes formed in the thickened cortex. Tetraspores were cultured from field-collected crusts of a morphology similar to that of cultured tetrasporophytes. They gave rise to upright gametophytic axes similar in morphology to this species as seen in the field.
  • Michio Masuda, Kazuhiro Kogame, Michael D. Guiry
    PHYCOLOGIA 35 5 421 - 434 1996年09月 [査読有り][通常論文]
     
    Tetraspores of the marine red alga Gymnogongrus griffithsiae (Turner) Martins (Phyllophoraceae, Gigartinales), the type species of the genus Gymnogongrus, gave rise in culture to erect, multiaxial, dichotomously divided thalli that developed into monoecious gametophytes. Procarps consisted of a large supporting cell and a three-celled carpogonial branch provided with a one- or two-celled sterile branchlet. Fertilized carpogonia fused with auxiliary cells, and initials of inwardly growing filaments were cut off from the auxiliary cells. Outwardly growing filaments subsequently developed from some parts of the inwardly growing filaments and directly from the auxiliary cells. They penetrated into the cortex of the erect axes and gave rise to pustule-like tetrasporoblasts, which in due course produced intercalary, seriate tetrasporangia in distinct sori. Released tetraspores developed into plants similar to those of the first generation. The relative fluorescent intensity of nuclear DNA stained with DAPI indicated that outer cortical cells of upright gametophytes, released spermatia, and tetraspores were haploid, whereas distal perithallial cells of tetrasporophytes and undivided tetrasporocytes were diploid. This confirms previous reports that meiosis occurs in the tetrasporangium during the formation of tetraspores. This type of life history is found only in some members of the Phyllophoraccae and a species of Pikea of the Dumontiaceae and is best referred to as the Gymnogongrus griffithsiae-type life history. The life history is considered to have arisen via multiple evolutionary events.
  • Kogame Kazuhiro
    Phycological research 44 2 85 - 94 Japanese Society of Phycology 1996年06月 [査読無し][通常論文]
  • Morphology and life history of Petalonia zosterifolia (Reinke) O. Kuntze (Scytosiphonales, Phaeophyceae) from Japan.
    Kogame, K, Kawai, H
    Japanese Journal of Phycology 41 29 - 37 1993年 [査読有り][通常論文]
  • OKUYAMA Hidetoshi, KOGAME Kazuhiro, TAKEDA Shigenobu
    Proceedings of the NIPR Symposium on Polar Biology 6 21 - 26 国立極地研究所 1993年01月 [査読無し][通常論文]
     
    Fatty acid composition of lipids from two strains of prymnesiophytes, seven strains of photosynthetic dinoflagellates, one strain of non-photosynthetic dinoflagellates and two strains of cryptomonads was examined with special emphasis on the presence or the absence of an octadecapentaenoic acid [18:5(n-3)]. Prymnesiophytes (Emiliania huxleyi and Gephyrocapsa oceanicd) and photosynthetic dinoflagellates [Amphidinium carterae, Prorocentrum micans, Protoceratiwn reticulatum, Pyrocystis lunula, Scrippsiella trochoidea, Symbiodinium microadriaticum (two strains)] examined all contained significant levels of 18:5(n-3) as a fatty acyl component. However, a non-photosynthetic dinoflagellate (Gymnodinium sp.) and cryptomonads (Cryptomonas sp. and Rhodomonas sp.) did not contain any level of 18:5(n-3). These results suggest that 18:5(n-3) is highly reliable as a specific marker of prymnesiophytes and photosynthetic dinoflagellates. 18:5(n-3) was found in glycolipids (monogalactosyl-diacylglycerol and digalactosyldiacylglycerol) and in phospholipids (phosphatidyl-choline) both in prymnesiophytes and dinoflagellates. Levels of 18:5(n-3) in glycolipids were higher than those in phospholipids, particularly in dinoflagellates.
  • H OKUYAMA, N MORITA, K KOGAME
    JOURNAL OF PHYCOLOGY 28 4 465 - 472 1992年08月 [査読有り][通常論文]
     
    The fatty acid composition of the prymnesiophyte strain B, a cold stenothermic microalga, was examined. The major fatty acids derived from the total lipids in this strain were myristic (14:0), palmitic (16:0), oleic (18:1-omega-9), linoleic (18:2-omega-6), octadecatetraenoic (18:4-omega-3), octadecapentaenoic (18:5-omega-3), and docosahexaenoic (22:6-omega-3) acids. Octadecapentaenoic acid (18.5-omega-3) was an unusual component and was characterized by mass spectrometry, infrared absorption spectrometry, and proton nuclear magnetic resonance spectrometry. Saturated fatty acids (14:0 and 16.0) and 18.5-omega-3 were distributed at significant levels in the major classes of galactolipids (monogalactosyldiacylglycerol, digalactosyldiacylglycerol, and sulfoquinovosyldiacylglycerol), phospholipids (phosphatidylcholine, phosphatidylglycerol, and phosphatidylethanolamine), and neutral lipids with the exception that phosphatidylethanolamine contained only trace amounts of 14:0. By contrast, 22:6-omega-3 was distributed in phospholipids and neutral lipids. A decrease in growth temperature from 5-degrees-C to 2-degrees-C was accompanied by a significant increase in levels of 18:5-omega-3 and 18:4-omega-3 with a concomitant decrease in the level of saturated fatty acids, whereas the level of 22:6-omega-3 was scarcely changed. These results suggest that, in prymnesiophyte strain B, eighteen-carbon polyunsaturated fatty acids with more than three double bonds, 18:5-omega-3 in particular, serve as modulators Of membrane fluidity. The potential role of 18.5-omega-3 as a specific marker for prymnesiophytes is also discussed.
  • Okuyama Hidetoshi, Kogame Kazuhiro, Mizuno Makoto, Kobayashi Wataru, Kanazawa Hajime, Ohtani Shuji, Watanabe Kentaro, Kanda Hiroshi
    Proceedings of the NIPR Symposium on Polar Biology 5 1 - 8 国立極地研究所 1992年03月 [査読有り][通常論文]
     
    Two psychrophilic strains of unicellular algae were isolated from seawater samples collected in the Antarctic Ocean. The one (strain A) was a species of Cymbella (Bacillariophyceae) and the other (strain B) was a species that belonged to the class Prymnesiophyceae (a prymnesiophyte). Optimum temperatures for growth of both the algae were between 2.5℃ and 5℃. Upper limit temperatures for growth of strain A (Cymbella sp.) and strain B were between 12.5℃ and 15℃ and between 7.5℃ and 10℃, respectively. We suggest that these algae should be categorized into extremely psychrophilic algae from their significantly lower cardinal temperatures for growth.
  • 小亀一弘, 吉田忠生
    藻類 36 1 52 - 54 1988年03月 [査読有り][通常論文]

MISC

書籍等出版物

  • 健康・機能性食品の基原植物事典
    佐竹元吉, 黒柳正典, 正山正洋, 和仁皓明 (担当:分担執筆範囲:藻類関係)
    中央法規出版 2016年
  • レーブン/ジョンソン生物学[上] 原書第７版 R/J Biology 翻訳委員会監訳
    小亀一弘, 川井浩史 (担当:共訳範囲:22章 進化の証拠)
    培風館 2005年
  • 北大自然史タイプコレクション－128年知の伝承－
    増田道夫, 小亀一弘, 加藤亜記, 谷昌也, 阿部剛史 (担当:分担執筆範囲:海藻)
    21世紀COE「新・自然史科学創成」／北海道大学総合博物館 2004年 2004年
  • 地球環境調査計測事典 第3巻沿岸域編
    竹内均 監修 (担当:分担執筆範囲:2章第四節 培養法 4-1 総説，褐藻類)
    フジ・テクノシステム 2003年
  • 21世紀初頭の藻学の現況
    堀輝三, 大野正夫, 堀口健雄 (担当:分担執筆範囲:藻類における性比)
    日本藻類学会 2002年
  • 新日本海藻誌
    吉田忠生 (担当:分担執筆範囲:カヤモノリ目（Scytosiphonales）)
    内田老鶴圃 1998年
  • 藻類の生活史集成 第２巻 褐藻・紅藻類
    堀輝三 編 (担当:分担執筆範囲:セイヨウハバノリ，カゴメノリ，フクロノリ)
    内田老鶴圃 1993年

講演・口頭発表等

所属学協会

  • 日本植物学会   International Phycological Society   

共同研究・競争的資金等の研究課題

  • 藻類リソースの収集・保存・提供
    日本医療研究開発機構：中核拠点整備プログラム ナショナルバイオリソースプロジェクト
    研究期間 : 2012年 -2021年 
    代表者 : 河地正伸
  • 北太平洋西部沿岸におけるコンブ類の種多様性とその由来の解明
    日本学術振興会：科学研究費補助金 基盤研究(B)
    研究期間 : 2013年 -2016年 
    代表者 : 四ツ倉典滋
  • 海産生物の分散障壁に関する研究
    日本学術振興会：科学研究費補助金 基盤研究(B)
    研究期間 : 2011年 -2015年 
    代表者 : Dick, Matthew
  • 日本・南ア両国による比較研究に基づくインド－太平洋海域の藻類の多様性と進化の解明
    科学技術振興機構：戦略的国際科学技術協力推進事業（研究交流型）「日本－南アフリカ研究交流」
    研究期間 : 2011年 -2013年 
    代表者 : 堀口健雄, ジョン ボルトン
  • サイズ変化をともなった円石藻の種分化の原因の解明
    日本学術振興会：科学研究費補助金 基盤研究(C)
    研究期間 : 2011年 -2013年 
    代表者 : 萩野恭子
  • 褐藻カヤモノリにおける種生物学的研究
    日本学術振興会：科学研究費補助金 基盤研究C
    研究期間 : 2009年 -2011年 
    代表者 : 小亀一弘
  • 褐藻カヤモノリにおける種内構造の解明
    日本学術振興会：科学研究費補助金 基盤研究(C)
    研究期間 : 2005年 -2007年 
    代表者 : 小亀一弘
  • 多価不飽和脂肪酸産生微生物のストレス応答
    国立極地研究所：一般共同研究
    研究期間 : 2004年 -2006年 
    代表者 : 奥山英登志
  • 複合分子解析による褐藻シオミドロ目（広義）の分子系統学的研究
    日本学術振興会：科学研究費補助金 基盤研究(C)
    研究期間 : 2002年 -2004年 
    代表者 : 小亀一弘
  • 極地産藻類の低温適応に関する生理・生化学的研究
    国立極地研究所：一般共同研究
    研究期間 : 1992年 -2004年 
    代表者 : 奥山英登志
  • アジアにおける生物多様性の地域特性の解明とその保全
    北海道大学：北海道大学教育改善推進費
    研究期間 : 1999年04月 -2000年03月 
    代表者 : 諏訪正明
  • 南極産植物の環境応答遺伝子
    国立極地研究所：一般共同研究
    研究期間 : 1998年 -2000年 
    代表者 : 奥山英登志
  • 海藻標本データベース
    日本学術振興会：科学研究費 研究成果公開促進費 データベース
    研究期間 : 1998年 -1999年 
    代表者 : 増田道夫
  • マレーシアの海藻の系統分類学的研究
    日本学術振興会：国際学術研究 基盤研究(A)
    研究期間 : 1997年 -1999年 
    代表者 : 増田道夫
  • 褐藻カヤモノリ目の分子系統学的研究
    日本学術振興会：化学研究費補助金 奨励研究(A)
    研究期間 : 1997年 -1998年 
    代表者 : 小亀一弘
  • 南極産微細藻類からの脂肪酸不飽和化酵素遺伝子のクローニング
    国立極地研究所：一般共同研究
    研究期間 : 1995年 -1997年 
    代表者 : 奥山英登志
  • 日本産褐藻カヤモノリ属の分類学的研究
    日本学術振興会：科学研究費補助金 奨励研究(A)
    研究期間 : 1994年04月 -1995年03月 
    代表者 : 小亀一弘
  • 北海道におけるカヤモノリ属(Scytosiphon)の分類学的研究
    北海道：平成元年度北海道科学研究費補助金
    研究期間 : 1989年04月 -1990年03月 
    代表者 : 小亀一弘

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