Seiji Tokumasu

Publications (19)25.89 Total impact

• Article: Combined molecular and morphological data for improving phylogenetic hypothesis in Dacrymycetes.

  Takashi Shirouzu, Dai Hirose, Franz Oberwinkler, Norihiro Shimomura, Nitaro Maekawa, Seiji Tokumasu
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  ABSTRACT: We analyzed the DNA sequences of four gene regions, 28S and 18S rDNA, the ITS region, and rpb2, to obtain a high-resolution phylogenetic tree of Dacrymycetes. In addition, we comparatively studied micro- and macromorphological characteristics of representative species. The traditional generic classification based on morphological characteristics was not reflected by our molecular phylogenies. Ancestral state reconstructions indicated that the morphology of basidia and clamp-connections are evolutionarily stable. In contrast, basidiocarps and basidiospore septation patterns appear variable. Dacrymyces unisporus shares the typical dolipores with non-perforate parenthesomes with the other dacrymycetous taxa but is a unique species in having predominantly non-bifurcate basidia and subglobose to ovoid basidiospores with transverse and longitudinal septations. In molecular phylogenies this species is a member of Dacrymycetes but always occupies the sister group position to the rest of the Dacrymycetes. Based on our results we propose a new genus, Unilacryma, for D. unisporus. For proper accommodation of this taxon, we introduce the family Unilacrymaceae and the order Unilacrymales.
  Mycologia 09/2012; · 2.03 Impact Factor
• Article: Dematiaceous hyphomycetes inhabiting decaying blackish needles ofAbies firma and their distribution in the Kanto district, Japan

  Susumu Iwamoto, Seiji Tokumasu
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  ABSTRACT: Dematiaceous mitosporic fungi darkening decaying fir needles on the ground were studied. Fungal communities on decaying, blackish fir needles were investigated in nine sites of the Kanto district, Japan, using a washing method. A total 108 taxa was recorded from 540 sampled needles. Among abundantly occurring dematiaceous fungi,Anungitea continua, A. uniseptata andEndophragmiella uniseptata were recognized as the major colonizers, forming a hyphal network on the surface of decaying fallen needles and darkening them. The effects of climate on the distributions of seven dematiaceous fungi included the major colonizers were analyzed. The abundance (proportion of needles colonized by a fungal species) ofChaetopsina fulva showed a significantly positive correlation with annual mean air temperature at each sampling site. No other significant correlations between the selected climatic factors and the distributions of dematiaceous fungi were recognized.
  Mycoscience 04/2012; 42(3):273-279. · 1.21 Impact Factor
• Article: Hirsutella proturicola sp. nov. isolated from a proturan, Baculentulus densus (Protura, Hexapoda)

  Yuko Kurihara, Takashi Shirouzu, Seiji Tokumasu, Shigeaki Harayama
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  ABSTRACT: A new species of Hirsutella, H. proturicola, isolated from a subterranean proturan (Baculentulus densus; Protura, Hexapoda), is described and illustrated. Hirsutella proturicola is characterized by producing monoblastic phialides of 24–51.5 × 2.5–5 μm with a slightly roughened neck, fusiform and curved conidia of 9–18 × 2.5–4 μm that have a truncate base and a papillate projection often capped with sheath-like mucilage, and pluricellular, globose to subglobose chlamydospores of 21–48 × 21–41.5 μm. This species is morphologically and phylogenetically close to H. rostrata, an acaropathogenic species, but can be distinguished from the size of the phialides and the size and shape of the conidia.
  Mycoscience 04/2012; 50(1):56-62. · 1.21 Impact Factor
• Article: Intraspecific groups of Umbelopsis ramanniana inferred from nucleotide sequences of nuclear rDNA internal transcribed spacer regions and sporangiospore morphology

  Yoshio Ogawa, Atsuhiro Suda, Kuniko Kusama-Eguchi, Kazuko Watanabe, Seiji Tokumasu
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  ABSTRACT: Umbelopsis ramanniana is a well-known species in this genus. A characteristic morphological feature of this fungus is the remarkable variation in the sporangiospore shape, which implies the genetic variations occur in the nucleotide sequences of the internal transcribed spacer (ITS) regions of the nuclear ribosomal DNA (nrDNA) in the U. ramanniana isolates. The relationship between the variations of the sequences of the nrDNA ITS regions and those of the sporangiospore morphology was investigated for 12 isolates of U. ramanniana collected in Europe. Neighbor-joining and parsimony analyses on the sequences suggested that these isolates split into three groups. Precise examination of the morphology showed that the isolates of those respective groups were different from each other in their sporangiospore shape. The present study implies at least three intraspecific groups exist in U. ramanniana and that the variations in the nucleotide sequences of the nrDNA ITS regions correlate well with those in the sporangiospore shape in these intraspecific groups.
  Mycoscience 04/2012; 46(6):343-351. · 1.21 Impact Factor
• Article: Sequence analyses of the 28S rRNA gene D1/D2 region suggest Dacrymyces (Heterobasidiomycetes, Dacrymycetales) is polyphyletic

  Takashi Shirouzu, Dai Hirose, Seiji Tokumasu
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  ABSTRACT: For the purpose of determining phylogenetic relationships within the Dacrymycetales, we conducted molecular phylogenetic analyses based on sequences of the 28S rRNA gene D1/D2 region using neighbor-joining and maximum-likelihood methods. Although the phylogenetic relationships at higher taxonomic levels were not resolved, we obtained some new information about inter- and intrageneric relationships in this order. Dacrymyces punctiformis formed a clade with Cerinomyces spp., and D. stillatus, D. minor, D. chrysospermus, and D. subalpinus constituted a clade with Guepiniopsis buccina. These clades and other Dacrymyces species were scattered over the Dacrymycetales lineage. The results suggest that Dacrymyces is polyphyletic. Our study suggests that basidiocarp morphology has limited taxonomic value at the generic or familial level and that there is a need for a taxonomic reassessment of this order, including a redescription of Dacrymyces.
  Mycoscience 04/2012; 48(6):388-394. · 1.21 Impact Factor
• Article: Polyphyly of intraspecific groups of Umbelopsis ramanniana and their genetic and morphological variation

  Yoshio Ogawa, Masato Sugiyama, Dai Hirose, Kuniko Kusama-Eguchi, Seiji Tokumasu
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  ABSTRACT: The taxonomic positions of three intraspecific groups of Umbelopsis ramanniana in the genus Umbelopsis were analyzed based on the nucleotide sequences of their nuclear large subunit ribosomal DNA (nLSU rDNA) D1/D2 region. The examined members of the genus Umbelopsis were resolved into two major clades, Clades I and II. The intraspecific groups of U. ramanniana were nested within Clade II together with U. westeae, U. swartii, U. autotrophica, U. gibberisopra, U. angularis, and U. fusiformis. In this major clade, the intraspecific groups of U. ramanniana were split into three polyphyletic subclades. This suggests that U. ramanniana is an assemblage of several genetically distinct species. Interestingly, in spite of the diverse sporangiospore shapes of the members of Clade II, the genetic variation among them was small. It is considered that their flexible sporangia membranes make it possible for them to develop various sporangiospore shapes. KeywordsMolecular phylogeny–Mucorales–nLSU rDNA D1/D2 region–Taxonomic position–Umbelopsidaceae
  Mycoscience 04/2012; 52(2):91-98. · 1.21 Impact Factor
• Article: Molecular phylogeny of terrestrial holocarpic endoparasitic peronosporomycetes, Haptoglossa spp., inferred from 18S rDNA

  Masateru Hakariya, Dai Hirose, Seiji Tokumasu
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  ABSTRACT: Phylogenetic relationships of seven isolates of the genus Haptoglossa parasitic on terrestrial nematodes within the Peronosporomycetes were analyzed using 18S rDNA sequence data with 21 peronosporomycetes, 2 marine stramenopilous flagellates, and 2 hyphochytridiomycetes. The marine stramenopilous flagellates and hyphochytridiomycetes were used as the outgroup. All Haptoglossa isolates formed a monophyletic clade and clustered with the marine genus Eurychasma. The clade of Haptoglossa and Eurychasma formed a sister-group to the clade that consisted of all other peronosporomycetes. These results suggest that the genus Haptoglossa and other terrestrial peronosporomycetes included in the two subclasses, the Saprolegniomycetidae and the Peronosporomycetidae, might have originally adapted to the terrestrial environment individually. In the maximum-likelihood (ML) analysis, the Haptoglossa clade was divided into three subclades, one aplanosporic species clade and two zoosporic species clades. Phylogenetic analyses of combined 18S rDNA and cox2 genes among five species of Haptoglossa supported the results of the ML analysis using 18S rDNA and suggested that zoosporic species may be separated into two lineages. This topology of the analysis may suggest that aplanosporic species diverged from zoosporic species.
  Mycoscience 02/2009; 50(2):130-136. · 1.21 Impact Factor
• Article: Morning dew and Tripospermum (Hyphomycetes)

  KEISUKE TUBAKI, SEIJI TOKUMASU, KATSUHIKO ANDO
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  ABSTRACT: Morning dew appears to be an important factor in the habitat of Tripospermum species. It affects both conidial development and liberation.
  Botanical Journal of the Linnean Society 06/2008; 91(1‐2):45 - 50. · 2.82 Impact Factor
• Article: A molecular phylogeny of Haptoglossa species, terrestrial peronosporomycetes (oomycetes) endoparasitic on nematodes

  Masateru Hakariya, Dai Hirose, Seiji Tokumasu
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  ABSTRACT: Phylogenetic relationships of seven Haptoglossa isolates were analyzed by using mitochondrial COII amino acid sequences with a data set of 34 peronosporomycetes. Haptoglossa isolates formed a single clade and appeared to be basal to the clade consisting of all other peronosporomycetes. The Haptoglossa clade was divided into two subclades: one clade consisted of five aplanosporic isolates and the other included one aplanosporic and one zoosporic isolate. These results indicate that the genus Haptoglossa is monophyletic, and patterns of infection cell formation reflect more the phylogenetic relationship between the species than patterns of sporogenesis.
  Mycoscience 01/2007; 48(3):169-175. · 1.21 Impact Factor
• Article: Two novel kickxellalean fungi, Mycoëmilia scoparia gen. sp. nov. and Ramicandelaber brevisporus sp. nov.

  Yuko Kurihara, Yousuke Degawa, Seiji Tokumasu
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  ABSTRACT: Mycoëmilia scoparia gen. sp. nov. is described as a new member of Kickxellales. It is characterized by lageniform sporocladia produced acrogenously in mass and bears wet and fusiform spores on the sporocladia. Ramicandelaber brevisporus sp. nov. is distinguished from the type species of the genus, R. longisporus, by producing much shorter asexual spores, (3-)8(-13) long fertile branches arising from a globose body, and lateral branches.
  Mycological Research 11/2004; 108(Pt 10):1143-52. · 2.81 Impact Factor
• Article: An original habitat of tempeh molds

  Yoshio Ogawa, Seiji Tokumasu, Keisuke Tubaki
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  ABSTRACT: Tempeh is a traditional Indonesian food made from soybeans fermented with Rhizopus species. Some researchers believe the original habitat of the tempeh molds may be closely related to fresh leaves of Hibiscus species because these leaves artificially infected with the tempeh molds are used to start tempeh fermentation in cottage-scale factories. To verify this hypothesis, we investigated the occurrence of Rhizopus species in Hibiscus leaves and identified the isolated Rhizopus strains precisely. Rhizopus oryzae, one of the tempeh molds, occurred in sample leaves of some Hibiscus species with considerable frequency. This result implies that tempeh molds that lived in Hibiscus leaves might have fermented soybeans accidentally when used to wrap the cooked soybeans. The original habitat of the tempeh mold could be fresh leaves of Hibiscus species.
  Mycoscience 07/2004; 45(4):271-276. · 1.21 Impact Factor
• Article: Paeciloxazine, a novel nematicidal antibiotic from Paecilomyces sp.

  Yoshinori Kanai, Tsukasa Fujimaki, Shin-ichiro Kochi, Hiroshi Konno, Susumu Kanazawa, Seiji Tokumasu
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  ABSTRACT: A novel nematicidal antibiotic, paeciloxazine has been isolated from the culture broth of a fungus Paecilomyces BAUA3058 strain. This compound, whose structure was determined by spectroscopic methods, has a pyrrolobenzoxazine skeleton. Paeciloxazine has moderate cidal activity against Rhabditis pseudoelongata and is weakly active against some insects.
  The Journal of Antibiotics 02/2004; 57(1):24-8. · 1.65 Impact Factor
• Article: The seasonal occurrence of endophytic fungus, Mycosphaerella buna, in Japanese beech, Fagus crenata

  Reiko Kaneko, Makoto Kakishima, Seiji Tokumasu
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  ABSTRACT: The seasonal occurrence of Mycosphaerella buna in leaves and contiguous organs of Fagus crenata was studied in a Japanese beech forest, Ibaraki, Japan, in 1998 and 1999. Mycosphaerella buna was not isolated from newly developed leaves in May, but it was isolated from asymptomatic leaves after June. The frequency of its occurrence gradually increased until leaffall. In contrast, M. buna was not isolated from overwintered buds, leaf petioles, or contiguous current-year twigs. The spermogonia and pseudothecia were observed in dead leaves after leaffall. The mature pseudothecia were found on dead leaves from May to July. The ascospores produced in the pseudothecia were suggested to infect newly developed leaves.
  Mycoscience 07/2003; 44(4):277-281. · 1.21 Impact Factor
• Article: Umbelopsis gibberispora sp. nov. from Japanese leaf litter and a clarification of Micromucor ramannianus var. angulisporus

  Masato Sugiyama, Seiji Tokumasu, Walter Gams
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  ABSTRACT:  Umbelopsis gibberispora is described as a new species in the genus Umbelopsis, Umbelopsidaceae, Mucorales. The species differs from others in this genus by ellipsoidal sporangiospores with unilaterally thickened walls. Phylogenetic analyses based on nuclear large subunit ribosomal DNA (nLSU rDNA) partial sequences suggest that U. gibberispora, U. swartii, and U. westeae form a clade together with the strains of Umbelopsis ramanniana. The ex-type strain of Micromucor ramannianus var. angulisporus is found to be very close to Umbelopsis vinacea, whereas other isolates identified under the former name in the sense of Linnemann fall in the U. ramanniana subclade. For these isolates, a new species, Umbelopsis angularis, is introduced. Phylogenetic relationships among Umbelopsis species are discussed related to their attributes of the sporangial wall and mature spore shapes.
  Mycoscience 05/2003; 44(3):217-226. · 1.21 Impact Factor
• Article: Zygospore formation inMortierella capitata

  Yousuke Degawa, Seiji Tokumasu
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  ABSTRACT: A novel type of zygospore formation is described in the heterothallic speciesMortierella capitata, which was repeatedly isolated from soils inhabited by pillbugs (Armadillidium vulgare, Isopoda). Zygospore formation was induced on media containing sterilized arthropods. Anisogamy and colorless zygospore walls are shared with other zygosporic species ofMortierella, but a unique feature ofM. capitata is the production of zygospores on elongated macrosuspensors which are covered by branches of the microsuspensors. This kind of zygosporogenesis is termed “capitata-type” here. The taxonomic position ofM. capitata is discussed based on the zygospore characteristics.
  Mycoscience 04/1997; 38(4):387-394. · 1.21 Impact Factor
• Article: Factors affecting microfungal diversity

  Yoshio Ogawa, Seiji Tokumasu, Keisuke Tubaki
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  ABSTRACT: Species diversity of microfungal communities in decaying oak leaves was analyzed based on the hyphal growth rates of the component species. Dominant species of a low-diversity community had faster hyphal growth rates, while dominant species of a high-diversity community had slower growth rates. These results implies that when the faster growing species became dominant, these species exhausted resources rapidly during the initial stage of fungal colonization. This exclusive utilization of resources made it impossible for other species to invade the substratum and led to a low diversity. Hyphal growth rates played an important role in determining the diversity of microfungal communities.
  Mycoscience 09/1996; 37(3):377-380. · 1.21 Impact Factor
• Article: Host range and potential distribution of ectomycorrhizal basidiomycete Suillus pictus in Japan

  Dai Hirose, Takashi Shirouzu, Seiji Tokumasu
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  ABSTRACT: The host range and potential distribution of the ectomycorrhizal basidiomycete Suillus pictus was evaluated using both in vitro inoculation and bait experiments with sterilized pine seedlings. In both experiments, three pines were selected as host, i.e. Pinus parviflora of the subgen. Strobus, and Pinus densiflora and Pinus thunbergii of the subgen. Pinus which are widely distributed in Japan. The inoculation experiment revealed that fine roots of seedlings of all pine species were colonized by S. pictus and formed typical ectomycorrhizas. The bait experiment with intact soil of a P. parviflora forest, which included propagules of S. pictus, clarified that S. pictus could form ectomycorrhizas on the fine roots of P. parviflora seedlings, while it could not form them on the fine roots of P. densiflora and P. thunbergii. In the bait experiment with intact soil of P. densiflora or P. thunbergii forest, ectomycorrhizas of S. pictus were not observed on the fine roots of P. parviflora. These results demonstrate that the fungus has the potential to form ectomycorrhizas with Pinus subgen. Pinus, but in natural conditions it only lives symbiotically with Pinus subgen. Strobus in Japan. The fact that this fungus has ecological host specificity provides useful information to study the bio- and phylogeography of this fungus.
  Fungal Ecology.
• Article: Internal transcribed spacer haplotype diversity and their geographical distribution in Dasyscyphella longistipitata (Hyaloscyphaceae, Helotiales) occurring on Fagus crenata cupules in Japan

  Tsuyoshi Hosoya, Dai Hirose, Michiru Fujisaki, Takashi Osono, Takanori Kubono, Seiji Tokumasu, Makoto Kakishima, 剛 細矢, 眞 柿嶌
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  ABSTRACT: Phylogeographic analysis of Dasyscyphella longistipitata (Hyaloscyphaceae, Helotiales), which occurs on decaying Fagus crenata cupules, was carried out. The ITS-5.8S regions of the 120 isolates from 12 sites in areas across Japan revealed 38 haplotypes, the majority of which comprised the haplotype designated H12 (42.5%). H12 was found in isolates from all sites, followed by H28 and H10, which were detected in isolates from 10 and 7 sites, respectively. Thirty-two haplotypes were obtained in single isolates. In the haplotype network, H12 was the root, and it formed interior clades with H28 and H10. Genetic diversity was higher in northern and southern Japan, but genetic distance was not correlated with geographical distance, nor with the phylogenetic clades of F. crenata. Therefore, it was concluded that D. longistipitata forms a genetic continuum that covers all of the areas in which it is distributed in Japan, with variations being generated in local populations from the major haplotypes.
• Article: Thysanophora penicillioides includes multiple genetically diverged groups that coexist respectively in Abies mariesii forests in Japan.

  Susumu Iwamoto, Seiji Tokumasu, Yoshihisa Suyama, Makoto Kakishima
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  ABSTRACT: We investigated intraspecific diversity and genetic structures of a saprotrophic fungus--Thysanophora penicillioides--based on sequences of nuclear ribosomal internal transcribed spacer (ITS) in 15 discontinuous Abies mariesii forests of Japan. In such a well-defined morphological species, numerous unexpected ITS variations were revealed: 12 ITS sequence types detected in 254 isolates collected from 15 local populations were classified into five ITS sequence groups. Maximally, four ITS groups consisted of seven ITS types coexisting in one population. However, group 1 was dominant with approximately 65%; in particular, one haplotype, 1a, was most dominant with approximately 60% in respective populations. Therefore, few differences were recognized in genetic structure among local populations, implying that the gene flow of each lineage of the fungus occurs among local populations without geographic limitations. However, minor haplotypes in some ITS groups were found only in restricted areas, suggesting that they might expand steadily from their places of origin to neighboring A. mariesii forests. Aggregating sequence data of seven European strains and four North American strains from various substrates to those of Japanese strains, 18 ITS sequence types and 28 variable sites were recognized. They were clustered into nine lineages by phylogenetic analyses of the beta-tubulin and combined ITS and beta-tubulin datasets. According to phylogenetic species recognition by the concordance of genealogies, respective lineages correspond to phylogenetic species. Plural phylogenetic species coexist in a local population in an A. mariesii forest in Japan.
  Mycologia 97(6):1238-50. · 2.03 Impact Factor