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Hisayoshi Nozaki - One of the best experts on this subject based on the ideXlab platform.
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morphology phylogeny and taxonomy of two species of colonial volvocine green algae from lake victoria tanzania
PLOS ONE, 2019Co-Authors: Hisayoshi Nozaki, Ryo Matsuzaki, Benedicto Boniphace Kashindye, Charles Nyarongo Ezekiel, Sophia Shaban, Masanobu Kawachi, Mitsuto Aibara, Masato NikaidoAbstract:The biodiversity and taxonomy of colonial volvocine green algae are important in ancient lakes in tropical regions. However, few taxonomic studies of these algae have been conducted in African ancient lakes. Here, we describe two species of colonial volvocine green algae in cultures originating from water samples from Lake Victoria, an ancient lake in Africa. One was identified as an undescribed morphological species of Eudorina; E. compacta sp. nov. This new species can be distinguished from other Eudorina species by its compactly arranged vegetative cells that form a hollow ellipsoidal colony. The other was identified as Colemanosphaera charkowiensis. The genus Colemanosphaera is new to Africa.
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alternative evolution of a spheroidal colony in volvocine algae developmental analysis of embryogenesis in astrephomene volvocales chlorophyta
BMC Evolutionary Biology, 2016Co-Authors: Shota Yamashita, Yoko Arakaki, Hiroko Kawaitoyooka, Akira Noga, Masafumi Hirono, Hisayoshi NozakiAbstract:Volvocine algae, which range from the unicellular Chlamydomonas to the multicellular Volvox with a germ–soma division of labor, are a model for the evolution of multicellularity. Within this group, the spheroidal colony might have evolved in two independent lineages: Volvocaceae and the goniacean Astrephomene. Astrephomene produces spheroidal colonies with posterior somatic cells. The feature that distinguishes Astrephomene from the volvocacean algae is lack of inversion during embryogenesis; the volvocacean embryo undergoes inversion after successive divisions to orient flagella toward the outside. The mechanisms of inversion at the molecular and cellular levels in volvocacean algae have been assessed in detail, particularly in Volvox carteri. However, embryogenesis in Astrephomene has not been subjected to such investigations. This study relied on light microscopy time-lapse imaging using an actively growing culture of a newly established strain to conduct a developmental analysis of Astrephomene as well as to perform a comparison with the similar spheroidal volvocacean Eudorina. During the successive divisions involved in Astrephomene embryogenesis, gradual rotation of daughter protoplasts resulted in movement of their apical portions toward the embryonic posterior, forming a convex-to-spheroidal cell sheet with the apical ends of protoplasts on the outside. Differentiation of the posterior somatic cells from the embryo periphery was traced based on cell lineages during embryogenesis. In contrast, in Eudorina, the rotation of daughter protoplasts did not occur during successive cell divisions; however, inversion occurred after such divisions, and a spheroidal embryo was formed. Indirect immunofluorescence microscopy of basal bodies and nuclei verified this difference between Astrephomene and Eudorina in the movement of embryonic protoplasts. These results suggest different tactics for spheroidal colony formation between the two lineages: rotation of daughter protoplasts during successive cell divisions in Astrephomene, and inversion after cell divisions in Eudorina. This study will facilitate further research into the molecular and genetic mechanisms of the parallel evolution of the spheroidal colony in volvocine algae.
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A taxonomic study of Eudorina unicocca (Volvocaceae, Chlorophyceae) and related species, based on morphology and molecular phylogeny
European Journal of Phycology, 2008Co-Authors: Toshihiro Yamada, Kazuyuki Miyaji, Hisayoshi NozakiAbstract:Colonial volvocacean algae engage in two types of sexual reproduction: isogamy and anisogamy/oogamy with sperm packets. This difference is an important generic diagnosis within the Volvocaceae. Although Yamagishiella differs from the anisogamous genus Eudorina in its isogamous sexual reproduction, the vegetative morphology and asexual reproduction characteristics of the two genera are indistinguishable, especially between Eudorina unicocca G. M. Smith and Yamagishiella unicocca (Rayburn et Starr) Nozaki. We re-examined morphological characteristics of E. unicocca and related species, using multiple strains of E. unicocca and Y. unicocca and molecular phylogenetic analyses. Strains from two Japanese lakes, which produced aplanospores and were solely asexual, could be assigned to either E. unicocca or Y. unicocca, based on traditional morphological diagnoses. However, a new morphological diagnosis (the difference in the distribution and number of contractile vacuoles on the cell surface) and molecular phylo...
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morphology and phylogeny of Eudorina minodii chodat nozaki et krienitz comb nov volvocales chlorophyta from germany
European Journal of Phycology, 2001Co-Authors: Hisayoshi Nozaki, Lothar KrienitzAbstract:Morphology, sexual reproduction and phylogeny of a colonial green alga collected from Germany were studied in culture. Light and electron microscopy of the gelatinous (extracellular) matrix of vegetative colonies, the absence of obligately somatic cells, and the anisogamous sexual reproduction with sperm packets in this alga indicated that it is assignable to the genus Eudorina. This German alga was similar to E. elegans Ehrenberg in its multiple pyrenoids of nearly identical size and almost identical sized vegetative cells in the colony, but differed from it in having a prominent tubular structure (flagellar sheath) surrounding each flagellum in the gelatinous matrix of the vegetative colonies. Sexual reproduction was homothallic and dioecious. On the other hand, the vegetative morphology agreed well with that of Pandorina minodii Chodat with regard to multiple pyrenoids and the prominent flagellar sheaths. Thus, a new combination, Eudorina minodii (Chodat) Nozaki et Krienitz, is proposed. Molecular phyl...
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Origin and evolution of the colonial volvocales (Chlorophyceae) as inferred from multiple, chloroplast gene sequences.
Molecular Phylogenetics and Evolution, 2000Co-Authors: Hisayoshi Nozaki, Kazuharu Misawa, Tadashi Kajita, Masahiro Kato, Seiichi Nohara, Makoto M WatanabeAbstract:A combined data set of DNA sequences (6021 bp) from five protein-coding genes of the chloroplast genome (rbcL, atpB, psaA, psaB, and psbC genes) were analyzed for 42 strains representing 30 species of the colonial Volvocales (Volvox and its relatives) and 5 related species of green algae to deduce robust phylogenetic relationships within the colonial green flagellates. The 4-celled family Tetrabaenaceae was robustly resolved as the most basal group within the colonial Volvocales. The sequence data also suggested that all five volvocacean genera with 32 or more cells in a vegetative colony (all four of the anisogamous/oogamous genera, Eudorina, Platydorina, Pleodorina, and Volvox, plus the isogamous genus Yamagishiella) constituted a large monophyletic group, in which 2 Pleodorina species were positioned distally to 3 species of Volvox. Therefore, most of the evolution of the colonial Volvocales appears to constitute a gradual progression in colonial complexity and in types of sexual reproduction, as in the traditional volvocine lineage hypothesis, although reverse evolution must be considered for the origin of certain species of Pleodorina. Data presented here also provide robust support for a monophyletic family Goniaceae consisting of two genera: Gonium and Astrephomene.
Annette W. Coleman - One of the best experts on this subject based on the ideXlab platform.
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comparison of Eudorina pleodorina its sequences of isolates from nature with those from experimental hybrids
American Journal of Botany, 2002Co-Authors: Annette W. ColemanAbstract:Internal transcribed spacer (ITS) regions of nuclear ribosomal repeats were compared among 50 Eudorina and Pleodorina isolates and two Volvox species known to clade with Eudorina species. Of the six major subclades found, four containing Eudorina and Pleodorina illinoisensis isolates, one containing Eudorina and Pleodorina indica, and one containing Volvox gigas and V. powersii, the basal branching order remains uncertain, but the positioning of isolates known to mate was always as nearest neighbors on the terminal branches of the tree. Four hybrid clones from a cross of E. elegans with P. illinoisensis, known from chromosome counts to be products of the failure of meiosis at zygote germination, contain both parental ITS repeat regions, as expected. However, they have in addition both crossover and other variant ITS cistrons among their many repeats of ITS. Such variation is limited to terminal regions of helices, as recognized from knowledge of RNA transcript secondary structure. Proper alignment then utilizes all of the nucleotide positions; the hybrid variants appear in positions intermediate between their parents in the tree. In fact, such variants seem to be hallmarks of recent hybridization events, since they were not found in any of the other 50 isolates.
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biogeography and speciation in the pandorina volvulina chlorophyta superclade
Journal of Phycology, 2001Co-Authors: Annette W. ColemanAbstract:Mating affinity, nuclear rDNA internal transcribed spacer (ITS) sequence, and geographic distribution of more than 100 isolates of Pandorina, Volvulina, and Yamagishiella were determined. Comparative analysis of ITS sequences reaffirmed the unity of Pandorina morum and its separation from all other species of Volvocaceae except those of Volvulina. This latter genus, represented by four species, appears to represent only morphological variants of several P. morum subclades. The P. morum clade (including also additional species such as P. smithii and P. colemaniae) encompasses an evolutionary span, as determined by comparison of ITS, greater than either of the multispecies genera Gonium or Eudorina. There are at least 30 Pandorina/Volvulina syngens, sexually isolated groups, so far as can be determined, among the current collection of strains. In addition, as in other volvocacaean genera, two clones are homothallic, capable of forming zygotes within a genetic clone. The existence of so many syngens suggests that considerable evolutionary diversification of the genes controlling gamete compatibility and intercross survival has occurred, unaccompanied by significant morphological change. Within each syngen, genetic distance increases with geographic distance between collection sites. At least half of the isolates studied must have been introduced northward since the Pleistocene. Although we probably know more about characters in this group of algae than any other algal group, in part because they are so easy to culture, we are still largely ignorant of what circumscribes their niche in nature. The study of all these organisms, distributed throughout the world presumably by the activities of shorebirds, emphasizes the evolutionary role of mating genes in the inevitable formation of new genetically isolated subclades in these eukaryotes and provides initial data on their rate of appearance versus their rate of distribution over the earth.
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phylogenetic relationships among isolates of Eudorina species volvocales chlorophyta inferred from molecular and biochemical data
Journal of Phycology, 1999Co-Authors: David G. Angeler, Michael Schagerl, Annette W. ColemanAbstract:Phylogenetic analyses of 19 strains representing five species of Eudorina, one strain of Pleodorina indica, and seven strains of Yamagishiella unicocca were carried out by sequencing the internal transcribed spacer region (ITS 1 and ITS 2) of the nuclear ribosomal DNA (rDNA) repeats. The sequence data resolved five phylogenetic groups, one consisting of Y. unicocca and the other four encompassing all the Eudorina species. Two isolates, Eudorina sp. (ASW 05157) and Pleodorina indica (ASW 05153), were of uncertain affiliation. Whereas one monophyletic group included strains of E. elegans only, the other strains of E. elegans appeared alongside E. cylindrica, E. illinoisensis, and E. unicocca var. unicocca in the other Eudorina clades. The distribution pattern of the carotenoid loroxanthin ([3R,3′R,6′R]-β,e-carotene-3,19,3′-triol), a systematically useful biochemical marker within chlorophycean flagellates, was shown to match the evaluated molecular data. Whereas it was either totally absent or universally present in six of the deduced phylogenetic lines, it occurred randomly in the E. elegans clade containing only E. elegans isolates. The results substantiated the current hypothesis that the unique vegetative morphology of E. elegans has independently arisen at various times during evolution and that it is not a marker of a monophyletic group.
Armin Hallmann - One of the best experts on this subject based on the ideXlab platform.
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Stable nuclear transformation of Eudorina elegans
BMC Biotechnology, 2013Co-Authors: Kai Lerche, Armin HallmannAbstract:Background A fundamental step in evolution was the transition from unicellular to differentiated, multicellular organisms. Volvocine algae have been used for several decades as a model lineage to investigate the evolutionary aspects of multicellularity and cellular differentiation. There are two well-studied volvocine species, a unicellular alga ( Chlamydomonas reinhardtii ) and a multicellular alga with differentiated cell types ( Volvox carteri ). Species with intermediate characteristics also exist, which blur the boundaries between unicellularity and differentiated multicellularity. These species include the globular alga Eudorina elegans , which is composed of 16–32 cells. However, detailed molecular analyses of E. elegans require genetic manipulation. Unfortunately, genetic engineering has not yet been established for Eudorina , and only limited DNA and/or protein sequence information is available. Results Here, we describe the stable nuclear transformation of E. elegans by particle bombardment using both a chimeric selectable marker and reporter genes from different heterologous sources. Transgenic algae resistant to paromomycin were achieved using the aminoglycoside 3^′-phosphotransferase VIII ( aph VIII) gene of Streptomyces rimosus , an actinobacterium, under the control of an artificial promoter consisting of two V. carteri promoters in tandem. Transformants exhibited an increase in resistance to paromomycin by up to 333-fold. Co-transformation with non-selectable plasmids was achieved with a rate of 50 - 100%. The luciferase ( gluc ) gene from the marine copepod Gaussia princeps , which previously was engineered to match the codon usage of C. reinhardtii , was used as a reporter gene. The expression of gluc was mediated by promoters from C. reinhardtii and V. carteri . Heterologous heat shock promoters induced an increase in luciferase activity (up to 600-fold) at elevated temperatures. Long-term stability and both constitutive and inducible expression of the co-bombarded gluc gene was demonstrated by transcription analysis and bioluminescence assays. Conclusions Heterologous flanking sequences, including promoters, work in E. elegans and permit both constitutive and inducible expression of heterologous genes. Stable nuclear transformation of E. elegans is now routine. Thus, we show that genetic engineering of a species is possible even without the resources of endogenous genes and promoters.
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Stable nuclear transformation of Eudorina elegans
BMC Biotechnology, 2013Co-Authors: Kai Lerche, Armin HallmannAbstract:A fundamental step in evolution was the transition from unicellular to differentiated, multicellular organisms. Volvocine algae have been used for several decades as a model lineage to investigate the evolutionary aspects of multicellularity and cellular differentiation. There are two well-studied volvocine species, a unicellular alga (Chlamydomonas reinhardtii) and a multicellular alga with differentiated cell types (Volvox carteri). Species with intermediate characteristics also exist, which blur the boundaries between unicellularity and differentiated multicellularity. These species include the globular alga Eudorina elegans, which is composed of 16–32 cells. However, detailed molecular analyses of E. elegans require genetic manipulation. Unfortunately, genetic engineering has not yet been established for Eudorina, and only limited DNA and/or protein sequence information is available. Here, we describe the stable nuclear transformation of E. elegans by particle bombardment using both a chimeric selectable marker and reporter genes from different heterologous sources. Transgenic algae resistant to paromomycin were achieved using the aminoglycoside 3′-phosphotransferase VIII (aphVIII) gene of Streptomyces rimosus, an actinobacterium, under the control of an artificial promoter consisting of two V. carteri promoters in tandem. Transformants exhibited an increase in resistance to paromomycin by up to 333-fold. Co-transformation with non-selectable plasmids was achieved with a rate of 50 - 100%. The luciferase (gluc) gene from the marine copepod Gaussia princeps, which previously was engineered to match the codon usage of C. reinhardtii, was used as a reporter gene. The expression of gluc was mediated by promoters from C. reinhardtii and V. carteri. Heterologous heat shock promoters induced an increase in luciferase activity (up to 600-fold) at elevated temperatures. Long-term stability and both constitutive and inducible expression of the co-bombarded gluc gene was demonstrated by transcription analysis and bioluminescence assays. Heterologous flanking sequences, including promoters, work in E. elegans and permit both constitutive and inducible expression of heterologous genes. Stable nuclear transformation of E. elegans is now routine. Thus, we show that genetic engineering of a species is possible even without the resources of endogenous genes and promoters.
Makoto M Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Origin and evolution of the colonial volvocales (Chlorophyceae) as inferred from multiple, chloroplast gene sequences.
Molecular Phylogenetics and Evolution, 2000Co-Authors: Hisayoshi Nozaki, Kazuharu Misawa, Tadashi Kajita, Masahiro Kato, Seiichi Nohara, Makoto M WatanabeAbstract:A combined data set of DNA sequences (6021 bp) from five protein-coding genes of the chloroplast genome (rbcL, atpB, psaA, psaB, and psbC genes) were analyzed for 42 strains representing 30 species of the colonial Volvocales (Volvox and its relatives) and 5 related species of green algae to deduce robust phylogenetic relationships within the colonial green flagellates. The 4-celled family Tetrabaenaceae was robustly resolved as the most basal group within the colonial Volvocales. The sequence data also suggested that all five volvocacean genera with 32 or more cells in a vegetative colony (all four of the anisogamous/oogamous genera, Eudorina, Platydorina, Pleodorina, and Volvox, plus the isogamous genus Yamagishiella) constituted a large monophyletic group, in which 2 Pleodorina species were positioned distally to 3 species of Volvox. Therefore, most of the evolution of the colonial Volvocales appears to constitute a gradual progression in colonial complexity and in types of sexual reproduction, as in the traditional volvocine lineage hypothesis, although reverse evolution must be considered for the origin of certain species of Pleodorina. Data presented here also provide robust support for a monophyletic family Goniaceae consisting of two genera: Gonium and Astrephomene.
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taxonomic re examination of a chinese strain labeled Eudorina sp volvocaceae chlorophyta based on morphological and dna sequence data
Phycological Research, 1998Co-Authors: Hisayoshi Nozaki, Lirong Song, Yongding Liu, Mikiya Hiroki, Makoto M WatanabeAbstract:SUMMARY A culture strain, CCFA 646, originating from the People's Republic of China and designated as ‘Eudorina sp.’ in the Culture Collection of Freshwater Algae at the Institute of Hydrobiology, Chinese Academy of Sciences, was re-examined taxonomically based on light and electron microscopy and molecular phylogenetic analyses. Vegetative colonies of CCFA 646 were sub-spherical or ovoid and contained 16 or 32 cells of identical size. The cells had a cup-shaped chloroplast with a single basal pyrenoid. During asexual reproduction, each daughter colony developed within a transparent vesicle inside the parental colony. Under the electron microscope, the vegetative colony exhibited a tripartite colonial boundary of the extracellular matrix. Inside the boundary, each cell was tightly enclosed by a dense fi-brillar layer of the matrix (cellular envelope). These morphological characteristics suggested that CCFA 646 is assignable to Eudorina unicocca G. M. Smith or Ya-magishiella unicocca (Rayburn et Starr) Nozaki. In addition, 1128 base pairs of the large subunit of ribulose-1, 5-bisphosphate carboxylase/oxygenase (rbcL) gene were sequenced from CCFA 646 and NIES-578 of Y. unicocca. Phylogenetic trees were constructed based on these sequence data as well as on the previously published rbcL gene sequences from five strains of Y. unicocca, six strains of four Eudorina species and 28 related species. The sequence data suggested with high bootstrap values that CCFA 646 and all six strains of Yama-gishiella form a monophyletic group positioned outside the large monophyletic group comprising Eudorina, Pleo-dorina and Volvox (except for sect. Volvox). Therefore, CCFA 646 can be assigned to Y. unicocca, which has not previously been reported from P. R. China.
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phylogenetic analysis of Eudorina species volvocaceae chlorophyta based on rbcl gene sequences1
Journal of Phycology, 1997Co-Authors: Hisayoshi Nozaki, Makoto M Watanabe, Motomi Ito, Hidenobu Uchida, Tsuneyoshi KuroiwaAbstract:Species and varieties in the genus Eudorina Ehrenberg (Volvocaceae, Chlorophyta) were evaluated on the basis of phylogenetic analyses of the large subunit ofribulose-1,5-bis-phosphate carboxylase/oxygenase (rbcL) gene sequences from 14 strains of four Eudorina species, as well as from nine species of Pleodorina and Volvox. The sequence data suggested that 10 of the 14 Eudorina strains form three separate and robust monophyletic groups within the nonmonophyletic genus Eudorina. The first group comprises all three strains of E. unicocca G. M. Smith; the second group consists of one of the E. elegans Ehrenberg var. elegans strains, the E. cylindrica Korshikov strain, and both E. illinoisensis (Kofoid) Pascher strains; and the third group consists of two monoecious varieties of E. elegans [two strains of E. elegans var. synoica Goldstein and one strain of E. elegans var. carteri (G. M. Smith) Goldstein]. In addition, E. illinoisensis represents a poly- or paraphyletic species within the second group. The remaining four strains, all of which are assigned to E. elegans var. elegans, are nonmonophyletic. Although their position in the phylogenetic trees is more or less ambiguous, they are ancestral to other taxa in the large anisogamous/oogamous monophyletic group including Eudorina, Pleodorina, and Volvox (except for sect. Volvox). Thus, the four Eudorina groups resolved in the present molecular phylogeny do not correspond with the species concepts of Eudorina based on vegetative morphology, but they do reflect the results of the previous intercrossing experiments and modes of monoecious and dioecious sexual reproduction.
Tsuneyoshi Kuroiwa - One of the best experts on this subject based on the ideXlab platform.
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phylogenetic analysis of Eudorina species volvocaceae chlorophyta based on rbcl gene sequences1
Journal of Phycology, 1997Co-Authors: Hisayoshi Nozaki, Makoto M Watanabe, Motomi Ito, Hidenobu Uchida, Tsuneyoshi KuroiwaAbstract:Species and varieties in the genus Eudorina Ehrenberg (Volvocaceae, Chlorophyta) were evaluated on the basis of phylogenetic analyses of the large subunit ofribulose-1,5-bis-phosphate carboxylase/oxygenase (rbcL) gene sequences from 14 strains of four Eudorina species, as well as from nine species of Pleodorina and Volvox. The sequence data suggested that 10 of the 14 Eudorina strains form three separate and robust monophyletic groups within the nonmonophyletic genus Eudorina. The first group comprises all three strains of E. unicocca G. M. Smith; the second group consists of one of the E. elegans Ehrenberg var. elegans strains, the E. cylindrica Korshikov strain, and both E. illinoisensis (Kofoid) Pascher strains; and the third group consists of two monoecious varieties of E. elegans [two strains of E. elegans var. synoica Goldstein and one strain of E. elegans var. carteri (G. M. Smith) Goldstein]. In addition, E. illinoisensis represents a poly- or paraphyletic species within the second group. The remaining four strains, all of which are assigned to E. elegans var. elegans, are nonmonophyletic. Although their position in the phylogenetic trees is more or less ambiguous, they are ancestral to other taxa in the large anisogamous/oogamous monophyletic group including Eudorina, Pleodorina, and Volvox (except for sect. Volvox). Thus, the four Eudorina groups resolved in the present molecular phylogeny do not correspond with the species concepts of Eudorina based on vegetative morphology, but they do reflect the results of the previous intercrossing experiments and modes of monoecious and dioecious sexual reproduction.
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Ultrastructure of the extracellular matrix and taxonomy of Eudorina, Pleodorina and Yamagishiella gen. nov. (Volvocaceae, Chlorophyta)
Phycologia, 1992Co-Authors: H. Nozaki, Tsuneyoshi KuroiwaAbstract:Vegetative colonies of Pandorina unicocca Rayburn et Starr, four taxa of Eudorina [E. elegans Ehrenberg (type species), E. illinoisensis (Kofoid) Pascher, E. unicocca G.M. Smith var. unicocca andE....
