92 results on '"Osami Misumi"'
Search Results
2. ESCRT Machinery Mediates Cytokinetic Abscission in the Unicellular Red Alga Cyanidioschyzon merolae
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Fumi Yagisawa, Takayuki Fujiwara, Tokiaki Takemura, Yuki Kobayashi, Nobuko Sumiya, Shin-ya Miyagishima, Soichi Nakamura, Yuuta Imoto, Osami Misumi, Kan Tanaka, Haruko Kuroiwa, and Tsuneyoshi Kuroiwa
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ESCRT ,cytokinesis ,cytokinetic abscission ,red alga ,Cyanidioschyzon merolae ,Biology (General) ,QH301-705.5 - Abstract
In many eukaryotes, cytokinesis proceeds in two successive steps: first, ingression of the cleavage furrow and second, abscission of the intercellular bridge. In animal cells, the actomyosin contractile ring is involved in the first step, while the endosomal sorting complex required for transport (ESCRT), which participates in various membrane fusion/fission events, mediates the second step. Intriguingly, in archaea, ESCRT is involved in cytokinesis, raising the hypothesis that the function of ESCRT in eukaryotic cytokinesis descended from the archaeal ancestor. In eukaryotes other than in animals, the roles of ESCRT in cytokinesis are poorly understood. To explore the primordial core mechanisms for eukaryotic cytokinesis, we investigated ESCRT functions in the unicellular red alga Cyanidioschyzon merolae that diverged early in eukaryotic evolution. C. merolae provides an excellent experimental system. The cell has a simple organelle composition. The genome (16.5 Mb, 5335 genes) has been completely sequenced, transformation methods are established, and the cell cycle is synchronized by a light and dark cycle. Similar to animal and fungal cells, C. merolae cells divide by furrowing at the division site followed by abscission of the intercellular bridge. However, they lack an actomyosin contractile ring. The proteins that comprise ESCRT-I–IV, the four subcomplexes of ESCRT, are partially conserved in C. merolae. Immunofluorescence of native or tagged proteins localized the homologs of the five ESCRT-III components [charged multivesicular body protein (CHMP) 1, 2, and 4–6], apoptosis-linked gene-2-interacting protein X (ALIX), the ESCRT-III adapter, and the main ESCRT-IV player vacuolar protein sorting (VPS) 4, to the intercellular bridge. In addition, ALIX was enriched around the cleavage furrow early in cytokinesis. When the ESCRT function was perturbed by expressing dominant-negative VPS4, cells with an elongated intercellular bridge accumulated—a phenotype resulting from abscission failure. Our results show that ESCRT mediates cytokinetic abscission in C. merolae. The fact that ESCRT plays a role in cytokinesis in archaea, animals, and early diverged alga C. merolae supports the hypothesis that the function of ESCRT in cytokinesis descended from archaea to a common ancestor of eukaryotes.
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- 2020
- Full Text
- View/download PDF
3. Morphology, taxonomy and mating-type loci in natural populations of Volvox carteri in Taiwan
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Hisayoshi Nozaki, Noriko Ueki, Mari Takusagawa, Shota Yamashita, Osami Misumi, Ryo Matsuzaki, Masanobu Kawachi, Yin-Ru Chiang, and Jiunn-Tzong Wu
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Mating-type locus ,Morphology ,Sexual reproduction ,Taxonomy ,Volvox ,Volvox carteri ,Botany ,QK1-989 - Abstract
Abstract Background Volvox carteri f. nagariensis is a model taxon that has been studied extensively at the cellular and molecular level. The most distinctive morphological attribute of V. carteri f. nagariensis within V. carteri is the production of sexual male spheroids with only a 1:1 ratio of somatic cells to sperm packets or androgonidia (sperm packet initials). However, the morphology of male spheroids of V. carteri f. nagariensis has been examined only in Japanese strains. In addition, V. carteri f. nagariensis has heterothallic sexuality; male and female sexes are determined by the sex-determining chromosomal region or mating-type locus composed of a > 1 Mbp linear chromosome. Fifteen sex-specific genes and many sex-based divergent shared genes (gametologs) are present within this region. Thus far, such genes have not been identified in natural populations of this species. Results During a recent fieldwork in Taiwan, we encountered natural populations of V. carteri that had not previously been recorded from Taiwan. In total, 33 strains of this species were established from water samples collected in Northern Taiwan. Based on sequences of the internal transcribed spacer 2 region of nuclear ribosomal DNA and the presence of asexual spheroids with up to 16 gonidia, the species was clearly identified as V. carteri f. nagariensis. However, the sexual male spheroids of the Taiwanese strains generally exhibited a 1:1 to > 50:1 ratio of somatic cells to androgonidia. We also investigated the presence or absence of several sex-specific genes and the sex-based divergent genes MAT3m, MAT3f and LEU1Sm. We did not identify recombination or deletion of such genes between the male and female mating-type locus haplotypes in 32 of the 33 strains. In one putative female strain, the female-specific gene HMG1f was not amplified by genomic polymerase chain reaction. When sexually induced, apparently normal female sexual spheroids developed in this strain. Conclusions Male spheroids are actually variable within V. carteri f. nagariensis. Therefore, the minimum ratio of somatic cells to androgonidia in male spheroids and the maximum number of gonidia in asexual spheroids may be diagnostic for V. carteri f. nagariensis. HMG1f may not be directly related to the formation of female spheroids in this taxon.
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- 2018
- Full Text
- View/download PDF
4. Development of a heat-shock inducible gene expression system in the red alga Cyanidioschyzon merolae.
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Nobuko Sumiya, Takayuki Fujiwara, Yusuke Kobayashi, Osami Misumi, and Shin-ya Miyagishima
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Medicine ,Science - Abstract
The cell of the unicellular red alga Cyanidioschyzon merolae contains a single chloroplast and mitochondrion, the division of which is tightly synchronized by a light/dark cycle. The genome content is extremely simple, with a low level of genetic redundancy, in photosynthetic eukaryotes. In addition, transient transformation and stable transformation by homologous recombination have been reported. However, for molecular genetic analyses of phenomena that are essential for cellular growth and survival, inducible gene expression/suppression systems are needed. Here, we report the development of a heat-shock inducible gene expression system in C. merolae. CMJ101C, encoding a small heat shock protein, is transcribed only when cells are exposed to an elevated temperature. Using a superfolder GFP as a reporter protein, the 200-bp upstream region of CMJ101C orf was determined to be the optimal promoter for heat-shock induction. The optimal temperature to induce expression is 50°C, at which C. merolae cells are able to proliferate. At least a 30-min heat shock is required for the expression of a protein of interest and a 60-min heat shock yields the maximum level of protein expression. After the heat shock, the mRNA level decreases rapidly. As an example of the system, the expression of a dominant negative form of chloroplast division DRP5B protein, which has a mutation in the GTPase domain, was induced. Expression of the dominant negative DRP5B resulted in the appearance of aberrant-shaped cells in which two daughter chloroplasts and the cells are still connected by a small DRP5B positive tube-like structure. This result suggests that the dominant negative DRP5B inhibited the final scission of the chloroplast division site, but not the earlier stages of division site constriction. It is also suggested that cell cycle progression is not arrested by the impairment of chloroplast division at the final stage.
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- 2014
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5. Complete mitochondrial and chloroplast DNA sequences of the freshwater green microalga Medakamo hakoo.
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Mari Takusagawa, Osami Misumi, Hisayoshi Nozaki, Shoichi Kato, Shinichiro Maruyama, Yayoi Tsujimoto-Inui, Fumi Yagisawa, Mio Ohnuma, Haruko Kuroiwa, Tsuneyoshi Kuroiwa, and Sachihiro Matsunaga
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MITOCHONDRIAL DNA ,CHLOROPLAST DNA ,PLANT mitochondria ,DNA sequencing ,GENETIC regulation ,WHOLE genome sequencing ,GREEN algae ,CHLOROPLAST membranes - Abstract
We report the complete organellar genome sequences of an ultrasmall green alga, Medakamo hakoo strain M-hakoo 311, which has the smallest known nuclear genome in freshwater green algae. Medakamo hakoo has 90.8-kb chloroplast and 36.5-kb mitochondrial genomes containing 80 and 33 putative protein-coding genes, respectively. The mitochondrial genome is the smallest in the Trebouxiophyceae algae studied so far. The GC content of the nuclear genome is 73%, but those of chloroplast and mitochondrial genomes are 41% and 35%, respectively. Codon usages in the organellar genomes have a different tendency from that in the nuclear genome. The organellar genomes have unique characteristics, such as the biased encoding of mitochondrial genes on a single strand and the absence of operon structures in chloroplast ribosomal genes. Medakamo hakoo will be helpful for understanding the evolution of the organellar genome and the regulation of gene expression in chloroplasts and mitochondria. [ABSTRACT FROM AUTHOR]
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- 2023
- Full Text
- View/download PDF
6. Smooth Loop-Like Mitochondrial Nucleus in the Primitive Red Alga Cyanidioschyzon merolae Revealed by Drying Treatment
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Haruko Kuroiwa, Tsuneyoshi Kuroiwa, Yamato Yoshida, Fumi Yagisawa, Shin-ya Miyagishima, Noriko Nagata, Osami Misumi, Yuuta Imoto, Takayuki Fujiwara, and Yuko Mogi
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Loop (topology) ,Cyanidioschyzon merolae ,medicine.anatomical_structure ,biology ,Genetics ,medicine ,Animal Science and Zoology ,Cell Biology ,Plant Science ,biology.organism_classification ,Nucleus ,Cell biology - Published
- 2021
7. Evolutionary significance of the ring-like plastid nucleus in the primitive red alga Cyanidioschyzon merolae as revealed by drying
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Tsuneyoshi Kuroiwa, Osami Misumi, Mio Ohnuma, Yuuta Imoto, Noriko Nagata, Fumi Yagisawa, and Haruko Kuroiwa
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0106 biological sciences ,0301 basic medicine ,Lineage (evolution) ,macromolecular substances ,Plant Science ,Red algae ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,Algae ,Botany ,Plastids ,Plastid ,Cell Nucleus ,biology ,Cell Biology ,General Medicine ,biology.organism_classification ,Biological Evolution ,Brown algae ,030104 developmental biology ,Cyanidioschyzon merolae ,chemistry ,Rhodophyta ,Green algae ,DNA ,010606 plant biology & botany - Abstract
Primary plastids originated from a free-living cyanobacterial ancestor and possess their own genomes-probably a few DNA copies. These genomes, which are organized in centrally located plastid nuclei (CN-type pt-nuclei), are produced from preexisting plastids by binary division. Ancestral algae with a CN-type pt-nucleus diverged and evolved into two basal eukaryotic lineages: red algae with circular (CL-type) pt-nuclei and green algae with scattered small (SN-type) pt-nuclei. Although the molecular dynamics of pt-nuclei in green algae and plants are now being analyzed, the process of the conversion of the original algae with a CN-type pt-nucleus to red algae with a CL-type one has not been studied. Here, we show that the CN-type pt-nucleus in the primitive red alga Cyanidioschyzon merolae can be changed to the CL-type by application of drying to produce slight cell swelling. This result implies that CN-type pt-nuclei are produced by compact packing of CL-type ones, which suggests that a C. merolae-like alga was the original progenitor of the red algal lineage. We also observed that the CL-type pt-nucleus has a chain-linked bead-like structure. Each bead is most likely a small unit of DNA, similar to CL-type pt-nuclei in brown algae. Our results thus suggest a C. merolae-like alga as the candidate for the secondary endosymbiont of brown algae.
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- 2020
8. Complete Mitochondrial and Plastid DNA Sequences of the Freshwater Green Microalga Medakamo hakoo
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Tsuneyoshi Kuroiwa, Mari Takusagawa, Haruko Kuroiwa, Osami Misumi, Fumi Yagisawa, Mio Ohnuma, Shoichi Kato, Hisayoshi Nozaki, Sachihiro Matsunaga, Yayoi Tsujimoto-Inui, and Shinichiro Maruyama
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Genetics ,biology ,Putative protein ,Trebouxiophyceae ,Plastid ,biology.organism_classification ,Gene ,Genome ,DNA sequencing - Abstract
Here we report the complete organellar genome sequences of Medakamo hakoo, a green alga identified in freshwater in Japan. It has 90.8-kb plastid and 36.5-kb mitochondrial genomes containing 80 and 33 putative protein coding genes, respectively, representing the smallest organellar genome among currently known core Trebouxiophyceae.
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- 2021
9. HBD1 protein with a tandem repeat of two HMG-box domains is a DNA clip to organize chloroplast nucleoids in
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Mari, Takusagawa, Yusuke, Kobayashi, Yoichiro, Fukao, Kumi, Hidaka, Masayuki, Endo, Hiroshi, Sugiyama, Takashi, Hamaji, Yoshinobu, Kato, Isamu, Miyakawa, Osami, Misumi, Toshiharu, Shikanai, and Yoshiki, Nishimura
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Proteomics ,DNA, Chloroplast ,Plant Biology ,HMG-box domain ,Biological Sciences ,Mass Spectrometry ,Chloroplast Proteins ,chloroplast nucleoid ,mitochondrial nucleoid ,Gene Expression Regulation ,Tandem Repeat Sequences ,HMG-Box Domains ,Mutation ,Genome, Chloroplast ,Chlamydomonas reinhardtii ,Phylogeny ,Protein Binding - Abstract
Significance Compaction of bulky DNA is a universal issue for all DNA-based life forms. Both chloroplasts and mitochondria maintain their own multicopy genomes organized as nucleoids, but the mechanism of DNA compaction remains obscure. Here, we discovered a chloroplast nucleoid protein (HBD1) that is highly similar to major mitochondrial nucleoid proteins transcription factor A, mitochondrial (TFAM), and ARS binding factor 2 protein (Abf2p) in terms of possessing two DNA-binding high mobility group box (HMG-box) domains. Our analyses of HBD1 based on DNA origami/atomic force microscopy showed that HBD1 is capable of compacting DNA by introducing U-turns and cross-strand bridges with the two HMG-box domains, indicating that proteins with two HMG-box domains could compact DNA in both mitochondrial and chloroplast nucleoids., Compaction of bulky DNA is a universal issue for all DNA-based life forms. Chloroplast nucleoids (chloroplast DNA–protein complexes) are critical for chloroplast DNA maintenance and transcription, thereby supporting photosynthesis, but their detailed structure remains enigmatic. Our proteomic analysis of chloroplast nucleoids of the green alga Chlamydomonas reinhardtii identified a protein (HBD1) with a tandem repeat of two DNA-binding high mobility group box (HMG-box) domains, which is structurally similar to major mitochondrial nucleoid proteins transcription factor A, mitochondrial (TFAM), and ARS binding factor 2 protein (Abf2p). Disruption of the HBD1 gene by CRISPR-Cas9–mediated genome editing resulted in the scattering of chloroplast nucleoids. This phenotype was complemented when intact HBD1 was reintroduced, whereas a truncated HBD1 with a single HMG-box domain failed to complement the phenotype. Furthermore, ectopic expression of HBD1 in the mitochondria of yeast Δabf2 mutant successfully complemented the defects, suggesting functional similarity between HBD1 and Abf2p. Furthermore, in vitro assays of HBD1, including the electrophoretic mobility shift assay and DNA origami/atomic force microscopy, showed that HBD1 is capable of introducing U-turns and cross-strand bridges, indicating that proteins with two HMG-box domains would function as DNA clips to compact DNA in both chloroplast and mitochondrial nucleoids.
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- 2021
10. HBD1 protein with a tandem repeat of two HMG-box domains is a DNA clip to organize chloroplast nucleoids in Chlamydomonas reinhardtii
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Yoshinobu Kato, Toshiharu Shikanai, Osami Misumi, Yoshiki Nishimura, Takashi Hamaji, Mari Takusagawa, Masayuki Endo, Yusuke Kobayashi, Yoichiro Fukao, Isamu Miyakawa, Hiroshi Sugiyama, and Kumi Hidaka
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0106 biological sciences ,0301 basic medicine ,Multidisciplinary ,Chloroplast nucleoid ,biology ,HMG-box ,Chlamydomonas reinhardtii ,biology.organism_classification ,01 natural sciences ,Cell biology ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,High-mobility group ,Chloroplast DNA ,chemistry ,Nucleoid ,DNA ,010606 plant biology & botany ,Mitochondrial nucleoid - Abstract
Compaction of bulky DNA is a universal issue for all DNA-based life forms. Chloroplast nucleoids (chloroplast DNA-protein complexes) are critical for chloroplast DNA maintenance and transcription, thereby supporting photosynthesis, but their detailed structure remains enigmatic. Our proteomic analysis of chloroplast nucleoids of the green alga Chlamydomonas reinhardtii identified a protein (HBD1) with a tandem repeat of two DNA-binding high mobility group box (HMG-box) domains, which is structurally similar to major mitochondrial nucleoid proteins transcription factor A, mitochondrial (TFAM), and ARS binding factor 2 protein (Abf2p). Disruption of the HBD1 gene by CRISPR-Cas9-mediated genome editing resulted in the scattering of chloroplast nucleoids. This phenotype was complemented when intact HBD1 was reintroduced, whereas a truncated HBD1 with a single HMG-box domain failed to complement the phenotype. Furthermore, ectopic expression of HBD1 in the mitochondria of yeast Δabf2 mutant successfully complemented the defects, suggesting functional similarity between HBD1 and Abf2p. Furthermore, in vitro assays of HBD1, including the electrophoretic mobility shift assay and DNA origami/atomic force microscopy, showed that HBD1 is capable of introducing U-turns and cross-strand bridges, indicating that proteins with two HMG-box domains would function as DNA clips to compact DNA in both chloroplast and mitochondrial nucleoids.
- Published
- 2021
11. Morphology, reproduction and taxonomy of Volvox dissipatrix (Chlorophyceae) from Thailand, with a description of Volvox zeikusii sp. nov
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Hisayoshi Nozaki, Ryo Matsuzaki, Mari Takusagawa, Osami Misumi, Masanobu Kawachi, and Wuttipong Mahakham
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0106 biological sciences ,biology ,010604 marine biology & hydrobiology ,Chlorophyceae ,Plant Science ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Maximum diameter ,Volvox ,Botany ,Molecular phylogenetics ,Taxonomy (biology) - Abstract
A strain of Volvox collected from Thailand produced a very large asexual spheroid with maximum diameter over 2 mm long. This Thai alga was identified as Volvox dissipatrix based on the deli...
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- 2019
12. Dynamics of the Evolution and Structure of Chloroplast Nucleoids: Finding the Mechanisms that Control the Shapes of Chloroplast Nucleoids
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Yoshiki Nishimura, Osami Misumi, and Yusuke Kobayashi
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- 2018
13. ESCRT Machinery Mediates Cytokinetic Abscission in the Unicellular Red Alga
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Fumi, Yagisawa, Takayuki, Fujiwara, Tokiaki, Takemura, Yuki, Kobayashi, Nobuko, Sumiya, Shin-Ya, Miyagishima, Soichi, Nakamura, Yuuta, Imoto, Osami, Misumi, Kan, Tanaka, Haruko, Kuroiwa, and Tsuneyoshi, Kuroiwa
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Cell and Developmental Biology ,Cyanidioschyzon merolae ,cytokinetic abscission ,cytokinesis ,macromolecular substances ,red alga ,Original Research ,ESCRT - Abstract
In many eukaryotes, cytokinesis proceeds in two successive steps: first, ingression of the cleavage furrow and second, abscission of the intercellular bridge. In animal cells, the actomyosin contractile ring is involved in the first step, while the endosomal sorting complex required for transport (ESCRT), which participates in various membrane fusion/fission events, mediates the second step. Intriguingly, in archaea, ESCRT is involved in cytokinesis, raising the hypothesis that the function of ESCRT in eukaryotic cytokinesis descended from the archaeal ancestor. In eukaryotes other than in animals, the roles of ESCRT in cytokinesis are poorly understood. To explore the primordial core mechanisms for eukaryotic cytokinesis, we investigated ESCRT functions in the unicellular red alga Cyanidioschyzon merolae that diverged early in eukaryotic evolution. C. merolae provides an excellent experimental system. The cell has a simple organelle composition. The genome (16.5 Mb, 5335 genes) has been completely sequenced, transformation methods are established, and the cell cycle is synchronized by a light and dark cycle. Similar to animal and fungal cells, C. merolae cells divide by furrowing at the division site followed by abscission of the intercellular bridge. However, they lack an actomyosin contractile ring. The proteins that comprise ESCRT-I–IV, the four subcomplexes of ESCRT, are partially conserved in C. merolae. Immunofluorescence of native or tagged proteins localized the homologs of the five ESCRT-III components [charged multivesicular body protein (CHMP) 1, 2, and 4–6], apoptosis-linked gene-2-interacting protein X (ALIX), the ESCRT-III adapter, and the main ESCRT-IV player vacuolar protein sorting (VPS) 4, to the intercellular bridge. In addition, ALIX was enriched around the cleavage furrow early in cytokinesis. When the ESCRT function was perturbed by expressing dominant-negative VPS4, cells with an elongated intercellular bridge accumulated—a phenotype resulting from abscission failure. Our results show that ESCRT mediates cytokinetic abscission in C. merolae. The fact that ESCRT plays a role in cytokinesis in archaea, animals, and early diverged alga C. merolae supports the hypothesis that the function of ESCRT in cytokinesis descended from archaea to a common ancestor of eukaryotes.
- Published
- 2019
14. Morphology, taxonomy and mating-type loci in natural populations of Volvox carteri in Taiwan
- Author
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Noriko Ueki, Jiunn-Tzong Wu, Ryo Matsuzaki, Yin-Ru Chiang, Mari Takusagawa, Masanobu Kawachi, Shota Yamashita, Hisayoshi Nozaki, and Osami Misumi
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0301 basic medicine ,Genetics ,Morphology ,Mating type ,biology ,Locus (genetics) ,Plant Science ,biology.organism_classification ,Volvox carteri ,Volvox carteri f. nagariensis ,Sexual reproduction ,lcsh:QK1-989 ,03 medical and health sciences ,030104 developmental biology ,Volvox ,lcsh:Botany ,Chromosomal region ,Original Article ,Mating-type locus ,Heterothallic ,Internal transcribed spacer ,Taxonomy - Abstract
Background Volvox carteri f. nagariensis is a model taxon that has been studied extensively at the cellular and molecular level. The most distinctive morphological attribute of V. carteri f. nagariensis within V. carteri is the production of sexual male spheroids with only a 1:1 ratio of somatic cells to sperm packets or androgonidia (sperm packet initials). However, the morphology of male spheroids of V. carteri f. nagariensis has been examined only in Japanese strains. In addition, V. carteri f. nagariensis has heterothallic sexuality; male and female sexes are determined by the sex-determining chromosomal region or mating-type locus composed of a > 1 Mbp linear chromosome. Fifteen sex-specific genes and many sex-based divergent shared genes (gametologs) are present within this region. Thus far, such genes have not been identified in natural populations of this species. Results During a recent fieldwork in Taiwan, we encountered natural populations of V. carteri that had not previously been recorded from Taiwan. In total, 33 strains of this species were established from water samples collected in Northern Taiwan. Based on sequences of the internal transcribed spacer 2 region of nuclear ribosomal DNA and the presence of asexual spheroids with up to 16 gonidia, the species was clearly identified as V. carteri f. nagariensis. However, the sexual male spheroids of the Taiwanese strains generally exhibited a 1:1 to > 50:1 ratio of somatic cells to androgonidia. We also investigated the presence or absence of several sex-specific genes and the sex-based divergent genes MAT3m, MAT3f and LEU1Sm. We did not identify recombination or deletion of such genes between the male and female mating-type locus haplotypes in 32 of the 33 strains. In one putative female strain, the female-specific gene HMG1f was not amplified by genomic polymerase chain reaction. When sexually induced, apparently normal female sexual spheroids developed in this strain. Conclusions Male spheroids are actually variable within V. carteri f. nagariensis. Therefore, the minimum ratio of somatic cells to androgonidia in male spheroids and the maximum number of gonidia in asexual spheroids may be diagnostic for V. carteri f. nagariensis. HMG1f may not be directly related to the formation of female spheroids in this taxon. Electronic supplementary material The online version of this article (10.1186/s40529-018-0227-9) contains supplementary material, which is available to authorized users.
- Published
- 2018
15. Identification of Holliday junction resolvases crucial for the chloroplast nucleoid morphology and segregation
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Yusuke Kobayashi, Osami Misumi, and Yoshiki Nishimura
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Chloroplast nucleoid ,Chemistry ,Holliday Junction Resolvase ,Identification (biology) ,Morphology (biology) ,Cell biology - Published
- 2018
16. Glycosyltransferase MDR1 assembles a dividing ring for mitochondrial proliferation comprising polyglucan nanofilaments
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Yuuta Imoto, Yoshihiko Akakabe, Tsuneyoshi Kuroiwa, Yuko Mogi, Kazunobu Matsushita, Fumi Yagisawa, Mio Ohnuma, Shunsuke Hirooka, Takashi Shimada, Osami Misumi, Masaki Yoshida, Yamato Yoshida, Takayuki Fujiwara, Haruko Kuroiwa, and Keiji Nishida
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0106 biological sciences ,0301 basic medicine ,Immunoelectron microscopy ,Mitochondrion ,Ring (chemistry) ,physiological processes ,01 natural sciences ,Genome ,03 medical and health sciences ,Organelle ,Glycosyltransferase ,polycyclic compounds ,Glucans ,neoplasms ,Plant Proteins ,Organelle Biogenesis ,Multidisciplinary ,biology ,Endosymbiosis ,Chemistry ,Glycosyltransferases ,Biological Sciences ,biology.organism_classification ,Mitochondria ,Cell biology ,030104 developmental biology ,Cyanidioschyzon merolae ,Biochemistry ,Rhodophyta ,biology.protein ,010606 plant biology & botany - Abstract
Mitochondria, which evolved from a free-living bacterial ancestor, contain their own genomes and genetic systems and are produced from preexisting mitochondria by binary division. The mitochondrion-dividing (MD) ring is the main skeletal structure of the mitochondrial division machinery. However, the assembly mechanism and molecular identity of the MD ring are unknown. Multi-omics analysis of isolated mitochondrial division machinery from the unicellular alga Cyanidioschyzon merolae revealed an uncharacterized glycosyltransferase, MITOCHONDRION-DIVIDING RING1 (MDR1), which is specifically expressed during mitochondrial division and forms a single ring at the mitochondrial division site. Nanoscale imaging using immunoelectron microscopy and componential analysis demonstrated that MDR1 is involved in MD ring formation and that the MD ring filaments are composed of glycosylated MDR1 and polymeric glucose nanofilaments. Down-regulation of MDR1 strongly interrupted mitochondrial division and obstructed MD ring assembly. Taken together, our results suggest that MDR1 mediates the synthesis of polyglucan nanofilaments that assemble to form the MD ring. Given that a homolog of MDR1 performs similar functions in chloroplast division, the establishment of MDR1 family proteins appears to have been a singular, crucial event for the emergence of endosymbiotic organelles.
- Published
- 2017
17. Rediscovery of the 'ancestral Volvox' species: Morphology and phylogenetic position of Pleodorina sphaerica (Volvocales, Chlorophyceae) from Thailand
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Masanobu Kawachi, Kayoko Yamamoto, Matthew D. Herron, Sujeephon Athibai, Mari Takusagawa, Wuttipong Mahakham, Hisayoshi Nozaki, Osami Misumi, and Frank Rosenzweig
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0106 biological sciences ,0301 basic medicine ,Volvocaceae ,biology ,Phylogenetic tree ,010604 marine biology & hydrobiology ,Zoology ,Plant Science ,Pleodorina ,Aquatic Science ,biology.organism_classification ,01 natural sciences ,03 medical and health sciences ,Volvocales ,Type species ,030104 developmental biology ,Volvox ,Phylogenetics ,Botany ,Molecular phylogenetics - Abstract
Pleodorina sphaerica Iyengar was considered to be a phylogenetic link between Volvox and the type species Pleodorina californica Shaw because it has small somatic cells distributed from the anterior to posterior poles in 64- or 128-celled vegetative colonies. However, cultural studies and molecular and ultrastructural data are lacking in P. sphaerica, and this species has not been recorded since 1951. Here, we performed light and electron microscopy and molecular phylogeny of P. sphaerica based on newly established culture strains originating from Thailand. Morphological features of the present Thai species agreed well with those of the previous studies of the Indian material of P. sphaerica and with those of the current concept of the advanced members of the Volvocaceae. The present P. sphaerica strains exhibited homothallic sexuality; male and facultative female colonies developed within a single clonal culture. Chloroplast multigene phylogeny demonstrated that P. sphaerica was sister to two o...
- Published
- 2017
18. Holliday junction resolvases mediate chloroplast nucleoid segregation
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Yusuke Kobayashi, Kumi Hidaka, Yoshiki Nishimura, Hiroshi Iwasaki, Toshiharu Shikanai, Osami Misumi, Masaki Odahara, Tsuneyoshi Kuroiwa, Kota Ishibashi, Hiroshi Sugiyama, Masafumi Hirono, and Masayuki Endo
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0301 basic medicine ,Genetics ,DNA, Cruciform ,Chloroplasts ,Multidisciplinary ,biology ,Chloroplast nucleoid ,Arabidopsis ,DNA, Chloroplast ,Holliday Junction Resolvases ,Chlamydomonas reinhardtii ,biology.organism_classification ,Cell biology ,Chloroplast ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,chemistry ,Holliday junction ,Arabidopsis thaliana ,Homologous recombination ,DNA - Abstract
Resolution achieved Chloroplasts possess multiple copies of their own chloroplast DNA that are packaged into DNA-protein complexes known as nucleoids. The shape, number, and distribution of chloroplast nucleoids change markedly depending on the cell cycle, developmental stage, and nutritional environment. Kobayashi et al. identified Holliday junction resolvase as a key factor in the dynamism of chloroplast nucleoids in the unicellular green algae Chlamydomonas reinhardtii . The gene encoding the resolvase is ubiquitously conserved among green plants. Disruption or down-regulation of this gene also disturbed chloroplast nucleoid organization and segregation in the land plant Arabidopsis thaliana . Science , this issue p. 631
- Published
- 2017
19. Primitive red alga Cyanidioschyzon merolae accumulates storage glucan and triacylglycerol under nitrogen depletion
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Yohei Nakajima, Mari Takusagawa, Takafumi Saito, and Osami Misumi
- Subjects
0301 basic medicine ,chemistry.chemical_classification ,biology ,Chemistry ,Starch ,food and beverages ,Red algae ,biology.organism_classification ,Applied Microbiology and Biotechnology ,Microbiology ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,Cyanidioschyzon merolae ,Enzyme ,Biochemistry ,Lipid droplet ,Green algae ,Sugar ,Glucan - Abstract
Most microalgae accumulate neutral lipids, including triacylglycerol (TAG), into spherical structures called lipid bodies (LBs) under environmental stress conditions such as nutrient depletion. In green algae, starch accumulation precedes TAG accumulation, and the starch is thought to be a substrate for TAG synthesis. However, the relationship between TAG synthesis and the starch content in red algae, as well as how TAG accumulation is regulated, is unclear. In this study, we cultured the primitive red alga Cyanidioschyzon merolae under nitrogen-depleted conditions, and monitored the formation of starch granules (SGs) and LBs using microscopy. SGs stained with potassium iodide were observed at 24 h; however, LBs stained specifically with BODIPY 493/503 were observed after 48 h. Quantitative analysis of neutral sugar and cytomorphological semi-quantitative analysis of TAG accumulation also supported these results. Thus, the accumulation of starch occurred and preceded the accumulation of TAG in cells of C. merolae. However, TAG accumulation was not accompanied by a decrease in the starch content, suggesting that the starch is a major carbon storage sink, at least under nitrogen-depleted conditions. Quantitative real-time PCR revealed that the mRNA levels of genes involved in starch and TAG synthesis rarely changed during the culture period, suggesting that starch and TAG synthesis in C. merolae are not controlled through gene transcription but at other stages, such as translation and/or enzymatic activity.
- Published
- 2016
20. Genome Size of the Ultrasmall Unicellular Freshwater Green Alga, Medakamo hakoo 311, as Determined by Staining with 4′,6-Diamidino-2-phenylindole after Microwave Oven Treatments: II. Comparison with Cyanidioschyzon merolae, Saccharomyces cerevisiae (n, 2n), and Chlorella variabilis
- Author
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Osami Misumi, Masahiro Fujishima, Yuuta Imoto, Noriko Nagata, Mio Ohnuma, Isamu Miyakawa, Haruko Kuroiwa, Fumi Yagisawa, and Tsuneyoshi Kuroiwa
- Subjects
0106 biological sciences ,0301 basic medicine ,Microwave oven ,Saccharomyces cerevisiae ,Cell Biology ,Plant Science ,Biology ,biology.organism_classification ,01 natural sciences ,Staining ,4 6 diamidino 2 phenylindole ,Chlorella variabilis ,03 medical and health sciences ,030104 developmental biology ,Cyanidioschyzon merolae ,Botany ,Genetics ,Animal Science and Zoology ,Genome size ,010606 plant biology & botany - Published
- 2016
21. Nitrogen Metabolism
- Author
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Sousuke, Imamura, Tanaka, Kan, Tsuneyoshi, Kuroiwa, Shinya, Miyagishima, Sachihiro, Matsunaga, Naoki, Sato, Hisayoshi, Nozaki, and Osami, Misumi
- Published
- 2018
22. MOESM1 of Morphology, taxonomy and mating-type loci in natural populations of Volvox carteri in Taiwan
- Author
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Nozaki, Hisayoshi, Ueki, Noriko, Takusagawa, Mari, Yamashita, Shota, Osami Misumi, Matsuzaki, Ryo, Kawachi, Masanobu, Yin-Ru Chiang, and Jiunn-Tzong Wu
- Abstract
Additional file 1: Figure S1. Alignment of nuclear rDNA ITS-2 sequences used for construction of the phylogenetic tree (Fig. 3). Figure S2. Results of genomic PCR of three strains using three pairs of HMG1f primers (Table 2 and Additional file 1: Figure S3). Numbers below primer pairs represent expected sizes of the PCR products. Lanes 1, 4 and 7: Eve (UTEX 1885). Lanes 2, 5 and 8: 2016-tw-nuk-8-2. Lanes 3, 6 and 9: 2016-0609-v-1. Figure S3. Primer positions of six HMG1f primers used in Fig. 3 and Additional file 1: Figure S1.
- Published
- 2018
- Full Text
- View/download PDF
23. Morphology and reproduction ofVolvox capensis(Volvocales, Chlorophyceae) from Montana, USA
- Author
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Kayoko Yamamoto, Matthew D. Herron, Shota Yamashita, Osami Misumi, Hisayoshi Nozaki, Noriko Ueki, and Frank Rosenzweig
- Subjects
biology ,media_common.quotation_subject ,Plant Science ,Aquatic Science ,biology.organism_classification ,Polyspermy ,Sperm ,Volvocales ,embryonic structures ,Botany ,Molecular phylogenetics ,Plant reproductive morphology ,Internal transcribed spacer ,Reproduction ,Ribosomal DNA ,media_common - Abstract
Volvox capensis was recorded previously only from South Africa. Here we established culture strains of this species from a sample collected in Montana, USA. Morphological details of asexual and sexual spheroids and molecular phylogeny of these strains were studied. The present alga was identified as V. capensis on the basis of morphological characteristics of asexual spheroids and zygotes. However, differences between the Montana and South African materials were recognized in number of sperm packets in a sexual, monoecious spheroid as well as in mode of gametic union between sperm and eggs. Possible polyspermy was observed in eggs of V. capensis by 4 0 -6-diamidino-2-phenylidole staining. Genetic difference between these two entities was small based on sequences of internal transcribed spacer 2 region of nuclear ribosomal DNA.
- Published
- 2015
24. Cytological Evidence of Cell-Nuclear Genome Size of a New Ultra-Small Unicellular Freshwater Green Alga, 'Medakamo hakoo' strain M-hakoo 311 I. Comparison with Cyanidioschyzon merolae and Ostreococcus tauri
- Author
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Yuuta Imoto, Mio Ohnuma, Tsuneyoshi Kuroiwa, Hisayoshi Nozaki, Osami Misumi, and Haruko Kuroiwa
- Subjects
Nuclear gene ,biology ,Strain (biology) ,Cell ,Cell Biology ,Plant Science ,biology.organism_classification ,Ostreococcus tauri ,Cyanidioschyzon merolae ,medicine.anatomical_structure ,Botany ,Genetics ,medicine ,Cytochemistry ,Animal Science and Zoology ,Genome size - Published
- 2015
25. Cyanidioschyzon Merolae : A New Model Eukaryote for Cell and Organelle Biology
- Author
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Tsuneyoshi Kuroiwa, Shinya Miyagishima, Sachihiro Matsunaga, Naoki Sato, Hisayoshi Nozaki, Kan Tanaka, Osami Misumi, Tsuneyoshi Kuroiwa, Shinya Miyagishima, Sachihiro Matsunaga, Naoki Sato, Hisayoshi Nozaki, Kan Tanaka, and Osami Misumi
- Subjects
- Cell cycle, Microbial genetics, Microbiology, Protista, Eukaryotic cells, Microbial genomics, Plant physiology
- Abstract
This comprehensive book highlights the importance of Cyanidioschyzon merolae (C. merolae), an ultrasmall unicellular red alga, as a model eukaryote organism. The chapters introduce recent studies on C. merolae, from culture, synchronization and isolation methods of nucleic acids, proteins and organelles for molecular biological and cytological analyses, as well as its application in genetic engineering of environmental-stress-tolerant crops and oil production. In addition to discussing recent advances based on the complete genome information and molecular biological techniques such as genetic modifications and bioinformatics, the book includes visualization aids demonstrating that both classical and recent imaging techniques of fluorescent and electron microscopy can be applied to analyses of C. merolae. This publication offers a definitive resource for both beginners and professionals studying C. merolae, particularly in the field of molecular biology, evolutionary biology, morphology, biochemistry and cell biology, as well as those interested in its applications in medical sciences and agriculture.
- Published
- 2017
26. Application of the Tolerance to Extreme Environment to Land Plants
- Author
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Tsuneyoshi Kuroiwa, Osami Misumi, and Shunsuke Hirooka
- Subjects
biology ,Chemistry ,Transgene ,fungi ,food and beverages ,Genetically modified crops ,APX ,biology.organism_classification ,Chloroplast ,chemistry.chemical_compound ,Cyanidioschyzon merolae ,Chlorophyll ,Botany ,biology.protein ,Arabidopsis thaliana ,Peroxidase - Abstract
The ability of the primitive red alga Cyanidioschyzon merolae to survive in acidic environments at high temperatures was applied to produce acid- and heat-tolerant transgenic plants. The C. merolae gene encoding a plasma membrane H+-ATPase was introduced into Arabidopsis thaliana, and the acid tolerance of the resulting transgenic plants was investigated. The transgenic seedlings were more acid-tolerant than the wild-type seedlings following a transient acid treatment. We also observed that the roots of transgenic plants grew longer than the wild-type roots. These results suggest that the C. merolae H+-ATPase may reinforce the acid tolerance of higher plants by enhancing proton pump activities. Furthermore, we produced transgenic A. thaliana plants overexpressing the C. merolae gene encoding the stromal ascorbate peroxidase (CmstAPX). Soluble APX activities were higher in CmstAPX-expressing plants than in the wild-type plants. Compared with the wild-type, the CmstAPX-expressing plants were more tolerant to high-temperature stress and oxidative stress induced by methyl viologen. Additionally, the CmstAPX-expressing plants retained the highest chlorophyll contents after treatments with methyl viologen and high temperatures. Furthermore, the stroma and chloroplasts of the CmstAPX-expressing plants remained intact, whereas they disintegrated in the wild-type controls. These findings imply that the increased APX activity in the chloroplasts of CmstAPX-expressing plants enhances heat tolerance by increasing reactive oxygen species-scavenging capabilities at high temperatures.
- Published
- 2017
27. Cyanidioschyzon merolae
- Author
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Naoki Sato, Tsuneyoshi Kuroiwa, Shin-ya Miyagishima, Osami Misumi, Sachihiro Matsunaga, Hisayoshi Nozaki, and Kan Tanaka
- Subjects
Cyanidioschyzon merolae ,medicine.anatomical_structure ,biology ,Organelle ,Cell ,medicine ,Eukaryote ,biology.organism_classification ,Cell biology - Published
- 2017
28. Primitive red alga Cyanidioschyzon merolae accumulates storage glucan and triacylglycerol under nitrogen depletion
- Author
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Mari, Takusagawa, Yohei, Nakajima, Takafumi, Saito, and Osami, Misumi
- Subjects
Nitrogen ,Rhodophyta ,Starch ,Lipid Droplets ,Genes, Plant ,Real-Time Polymerase Chain Reaction ,Glucans ,Triglycerides - Abstract
Most microalgae accumulate neutral lipids, including triacylglycerol (TAG), into spherical structures called lipid bodies (LBs) under environmental stress conditions such as nutrient depletion. In green algae, starch accumulation precedes TAG accumulation, and the starch is thought to be a substrate for TAG synthesis. However, the relationship between TAG synthesis and the starch content in red algae, as well as how TAG accumulation is regulated, is unclear. In this study, we cultured the primitive red alga Cyanidioschyzon merolae under nitrogen-depleted conditions, and monitored the formation of starch granules (SGs) and LBs using microscopy. SGs stained with potassium iodide were observed at 24 h; however, LBs stained specifically with BODIPY 493/503 were observed after 48 h. Quantitative analysis of neutral sugar and cytomorphological semi-quantitative analysis of TAG accumulation also supported these results. Thus, the accumulation of starch occurred and preceded the accumulation of TAG in cells of C. merolae. However, TAG accumulation was not accompanied by a decrease in the starch content, suggesting that the starch is a major carbon storage sink, at least under nitrogen-depleted conditions. Quantitative real-time PCR revealed that the mRNA levels of genes involved in starch and TAG synthesis rarely changed during the culture period, suggesting that starch and TAG synthesis in C. merolae are not controlled through gene transcription but at other stages, such as translation and/or enzymatic activity.
- Published
- 2016
29. Analysis of triacylglycerol accumulation under nitrogen deprivation in the red alga Cyanidioschyzon merolae
- Author
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Takashi Moriyama, Naoki Sato, Natsumi Mori, Masakazu Toyoshima, and Osami Misumi
- Subjects
0106 biological sciences ,0301 basic medicine ,Nitrogen ,Plastid membrane ,Photosynthesis ,Endoplasmic Reticulum ,01 natural sciences ,Microbiology ,03 medical and health sciences ,chemistry.chemical_compound ,Membrane Lipids ,Phycobilisomes ,Plastid ,Triglycerides ,biology ,Endoplasmic reticulum ,Fatty Acids ,food and beverages ,biology.organism_classification ,Metabolic pathway ,030104 developmental biology ,Cyanidioschyzon merolae ,Biochemistry ,chemistry ,Chlorophyll ,Biofuels ,Rhodophyta ,Phosphatidylcholines ,Phycobilisome ,010606 plant biology & botany - Abstract
Triacylglycerol (TAG) produced by microalgae is a potential source of biofuel. Although various metabolic pathways in TAG synthesis have been identified in land plants, the pathway of TAG synthesis in microalgae remains to be clarified. The unicellular rhodophyte Cyanidioschyzon merolae has unique properties as a producer of biofuel because of easy culture and feasibility of genetic engineering. Additionally, it is useful in the investigation of the pathway of TAG synthesis, because all of the nuclear, mitochondrial and plastid genomes have been completely sequenced. We found that this alga accumulated TAG under nitrogen deprivation. Curiously, the amount and composition of plastid membrane lipids did not change significantly, whereas the amount of endoplasmic reticulum (ER) lipids increased with considerable changes in fatty acid composition. The nitrogen deprivation did not decrease photosynthetic oxygen evolution per chlorophyll significantly, while phycobilisomes were degraded preferentially. These results suggest that the synthesis of fatty acids is maintained in the plastid, which is used for the synthesis of TAG in the ER. The accumulated TAG contained mainly 18 : 2(9,12) at the C-2 position, which could be derived from phosphatidylcholine, which also contains this acid at the C-2 position.
- Published
- 2016
30. Lipid Droplets of Bacteria, Algae and Fungi and a Relationship between their Contents and Genome Sizes as Revealed by BODIPY and DAPI Staining
- Author
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Takayuki Fujiwara, Osami Misumi, Nobuko Sumiya, Haruko Kuroiwa, Tsuneyoshi Kuroiwa, Mio Ohnuma, Yuuta Imoto, and Shin-ya Miyagishima
- Subjects
biology ,Cell Biology ,Plant Science ,biology.organism_classification ,Genome ,Staining ,chemistry.chemical_compound ,Cyanidioschyzon merolae ,chemistry ,Algae ,Biochemistry ,Lipid droplet ,Botany ,Genetics ,Animal Science and Zoology ,DAPI ,BODIPY ,Genome size - Published
- 2012
31. Identification of the plastid division gene PDR1
- Author
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Osami Misumi, Kazunobu Matsushita, Takayuki Fujiwara, Fumi Yagisawa, Mio Ohnuma, Yuuta Imoto, Yamato Yoshida, Haruko Kuroiwa, Tsuneyoshi Kuroiwa, Shigeyuki Kawano, Masaki Yoshida, and Shunsuke Hirooka
- Subjects
Identification (biology) ,Computational biology ,Division (mathematics) ,Biology ,Plastid ,Gene - Published
- 2012
32. Finding Holliday Junction Resolvases: A Crucial Factor for Chloroplast Nucleoid Segregation
- Author
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Osami Misumi, Yoshiki Nishimura, and Yusuke Kobayashi
- Subjects
0301 basic medicine ,03 medical and health sciences ,030104 developmental biology ,Chloroplast nucleoid ,Holliday Junction Resolvase ,Genetics ,Animal Science and Zoology ,Cell Biology ,Plant Science ,Biology ,Cell biology - Published
- 2017
33. Phototaxis in the Unicellular Red Algae Cyanidioschyzon merolae and Cyanidium caldarium
- Author
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Osami Misumi, Mio Ohnuma, and Tsuneyoshi Kuroiwa
- Subjects
education.field_of_study ,biology ,Population ,Cell Biology ,Plant Science ,Liquid medium ,Red algae ,Cyanidium caldarium ,biology.organism_classification ,Caldarium ,Cyanidioschyzon merolae ,Botany ,Genetics ,Phototaxis ,Biophysics ,Animal Science and Zoology ,Cyanidiaceae ,education - Abstract
Phototaxis of 2 cyanidiaceae, Cyanidioschyzon merolae and Cyanidium caldarium, was studied by population experiments. We found that cells of both C. merolae and C. caldarium moved towards light in liquid medium, but that the degree of migration was quite different. When laterally illuminated, most of the C. merolae cells moved towards light at a velocity of 0.27 mm/h. In contrast, only a small proportion of C. caldarium cells showed migration towards light and most of the cells remained dispersed. The exterior cell surface of C. merolae was observed by scanning electron microscopy. It appeared thick and flexible enough to enable crawling movement.
- Published
- 2011
34. Proteomic comparison between interphase and metaphase of isolated chloroplasts of Cyanidioschyzon merolae (Cyanidiophyceae, Rhodophyta)
- Author
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Takayuki Fujiwara, Tsuneyoshi Kuroiwa, Yamato Yoshida, Masaki Yoshida, Haruko Kuroiwa, and Osami Misumi
- Subjects
Gel electrophoresis ,Plant Science ,Aquatic Science ,Biology ,biology.organism_classification ,Agricultural and Biological Sciences (miscellaneous) ,Molecular biology ,Chloroplast ,Cyanidioschyzon merolae ,Biochemistry ,Proteome ,biology.protein ,Interphase ,Plastid ,FtsZ ,Metaphase - Abstract
SUMMARY With the completion of the Cyanidioschyzon merolae genome project, detailed analysis of organelle proteins with mass spectrometry has now become possible. Chloroplasts of the unicellular red alga Cyanidioschyzon merolae De Luca, Taddei et Varano (Rhodophyta, Cyanidiophyceae) were isolated from synchronized culture and the chloroplast lysates of both interphase and metaphase cells were prepared and subjected to 2D-polyacrylamide gel electrophoresis. A total of 355 spots (170 identical spots) were recognized and quantified and then analyzed using mass spectrometry. A total of 105 proteins were identified, including 18 proteins for posttranslational functions, 17 photosynthesis-related proteins, 10 carbohydrate-related proteins, 15 proteins of unknown functions, and eight proteins predicted to be contaminated from other organelles. On the basis of spot quantity, photosynthesis-related proteins were most dominant (45.3% in interphase and 56.4% in metaphase). In particular, the proteins forming phycobilisomal complexes were abundant. Comparison of interphase with metaphase revealed that CMG086C (aminomethyltransferase) notably increased in interphase. CMN235C (similar to chlorophyll a/b-binding protein, CP24) increased in metaphase in agreement with a previously performed microarray analysis. Both CMQ295C (cell division protein FtsH) and CMS004C (plastid division protein FtsZ) increased in interphase. Seven proteins were detected to be interphase-specific, and 12 proteins were metaphase-specific. Proteins of unknown functions were poorly characterized by homology search, although thioredoxin-like domains were predicted in several proteins.
- Published
- 2010
35. Chloroplasts Divide by Contraction of a Bundle of Nanofilaments Consisting of Polyglucan
- Author
-
Yamato Yoshida, Tsuneyoshi Kuroiwa, Masaki Yoshida, Yuuta Imoto, Shigeyuki Kawano, Kazunobu Matsushita, Shunsuke Hirooka, Osami Misumi, Fumi Yagisawa, Mio Ohnuma, Takayuki Fujiwara, and Haruko Kuroiwa
- Subjects
Proteomics ,Chloroplasts ,Multidisciplinary ,Cell division ,Algal Proteins ,Down-Regulation ,Glycosyltransferases ,Biology ,biology.organism_classification ,law.invention ,Chloroplast ,Cyanidioschyzon merolae ,Biochemistry ,law ,Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ,Rhodophyta ,Organelle ,Glycosyltransferase ,biology.protein ,Electron microscope ,Plastid ,Glucans ,Gene ,Cytoskeleton ,Protein Binding - Abstract
Chloroplast Division Machinery The machinery for photosynthesis, which captures the Sun's energy to generate carbohydrates, generally resides in subcellular chloroplasts of plant cells. Chloroplasts must divide as the plant cell divides, but to do so requires their own plastid dividing machinery. Yoshida et al. (p. 949 : see the cover) have now analyzed the plastid dividing machinery of the single-celled alga Cyanidioschyzon merolae , whose cells each contain a single chloroplast. The plastid dividing machinery is made up of polysaccharide chains and the proteins that make them, which together generate a ring that constricts to physically divide the chloroplast.
- Published
- 2010
36. The Coiled-Coil Protein VIG1 Is Essential for Tethering Vacuoles to Mitochondria during Vacuole Inheritance of Cyanidioschyzon merolae
- Author
-
Fumi Yagisawa, Takayuki Fujiwara, Tsuneyoshi Kuroiwa, Haruko Kuroiwa, Masaki Yoshida, Mio Ohnuma, Keiji Nishida, Satoru Watanabe, Osami Misumi, Kan Tanaka, and Yamato Yoshida
- Subjects
biology ,Cell division ,Gene Expression Profiling ,Algal Proteins ,Cell Cycle ,Cell Biology ,Plant Science ,Vacuole ,Mitochondrion ,biology.organism_classification ,Vacuole inheritance ,Endocytosis ,Cell biology ,Mitochondria ,Cytosol ,Cyanidioschyzon merolae ,Microscopy, Electron, Transmission ,Sequence Analysis, Protein ,Organelle ,Rhodophyta ,Vacuoles ,Research Articles - Abstract
Vacuoles/lysosomes function in endocytosis and in storage and digestion of metabolites. These organelles are inherited by the daughter cells in eukaryotes. However, the mechanisms of this inheritance are poorly understood because the cells contain multiple vacuoles that behave randomly. The primitive red alga Cyanidioschyzon merolae has a minimum set of organelles. Here, we show that C. merolae contains about four vacuoles that are distributed equally between the daughter cells by binding to dividing mitochondria. Binding is mediated by VIG1, a 30-kD coiled-coil protein identified by microarray analyses and immunological assays. VIG1 appears on the surface of free vacuoles in the cytosol and then tethers the vacuoles to the mitochondria. The vacuoles are released from the mitochondrion in the daughter cells following VIG1 digestion. Suppression of VIG1 by antisense RNA disrupted the migration of vacuoles. Thus, VIG1 is essential for tethering vacuoles to mitochondria during vacuole inheritance in C. merolae.
- Published
- 2010
37. The Overexpression of Cyanidioschyzon merolae S-adenosylmethionine Synthetase Enhances Salt Tolerance in Transgenic Arabidopsis thaliana
- Author
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Tsuneyoshi Kuroiwa, Takayuki Sakajiri, Haruko Kuroiwa, Shunsuke Hirooka, Satoshi Doi, Takayuki Fujiwara, Osami Misumi, Keita Asano, Mio Ohnuma, and Masaki Yoshida
- Subjects
Genetics ,Transgene ,Cell Biology ,Plant Science ,Genetically modified crops ,Biology ,Plant cell ,biology.organism_classification ,law.invention ,Transformation (genetics) ,Cyanidioschyzon merolae ,Biochemistry ,law ,Recombinant DNA ,Extreme environment ,Animal Science and Zoology ,Gene - Abstract
High salinity is one of the most serious threats to crop production. The primitive red alga, Cyanidioschyzon merolae, inhabits an extreme environment (42°C, pH 2.5, high salt, metal ion). We have utilized the ability of C. merolae cells to adapt to 0.3 M sodium salt, as well as information from its fully sequenced genome, to produce salt-tolerant transgenic higher plants. To reveal the mechanisms of high salt tolerance, we analyzed, by RT-PCR, genes that were expressed at high levels after salt stress (0.3 M NaCl). The C. merolae S-adenosylmethionine synthetase (CmSAMS) gene that codes for an enzyme in the polyamine biosynthesis pathway was expressed at high levels (4 to 5 expression ratio). Our results are in accordance with our previously reported DNA microarray data. The CmSAMS gene codes for a 393-aa protein contain 3 conserved domains at the N-terminal and a semi-conserved domain at the C-terminal. The particle bombardment method revealed that the recombinant CmSAMS-green fluorescent protein was localized in the cytoplasm and the nuclei of the plant cells. To further investigate tolerance to salt stress, we produced, by Agrobacterium-mediated transformation, 4 transgenic Arabidopsis thaliana plant lines expressing CmSAMS. Compared to wild-type plants, the CmSAMS transgenic plants were more tolerant to salt stress, clearly defining a role for the CmSAMS gene in conferring salt-stress tolerance.
- Published
- 2010
38. The Vacuole Binding to Mitochondria by VIG1 Contributes an Equal Inheritance of the Vacuoles in Cyanidioschyzon merolae
- Author
-
Mio Ohnuma, Tsuneyoshi Kuroiwa, Keiji Nishida, Takayuki Fujiwara, Osami Misumi, Yamato Yoshida, Haruko Kuroiwa, Fumi Yagisawa, and Masaki Yoshida
- Subjects
biology ,Cell division ,Cell Biology ,Plant Science ,Vacuole ,biology.organism_classification ,Endocytosis ,Vacuole inheritance ,Cell biology ,Cyanidioschyzon merolae ,medicine.anatomical_structure ,Lysosome ,Organelle ,Genetics ,medicine ,Animal Science and Zoology ,Organelle inheritance - Abstract
Vacuoles function in endocytosis, storage and digestion of metabolites in eukaryotic cells. They are inherited by the daughter cells. However, the mechanisms of vacuole inheritance are poorly understood because the cells contain multiple vacuoles that behave randomly. Cyanidioschyzon merolae cell has a minimum set of organelles. The vacuoles were equally inherited by the daughter cells by binding to dividing mitochondria. The binding was mediated by VIG1. However, the role of the binding in the vacuoles inheritance was poorly understood. We examined it by inhibiting the binding cytochemically. The vacuoles, which were not bound to mitochondria, were not equally inherited by the daughter cells. As the results, vacuole-less daughter cells were generated. These results suggested that the binding contributed the equal inheritance of vacuoles and ensured the permanence of vacuoles in daughter cells.
- Published
- 2010
39. Identification of novel proteins in isolated polyphosphate vacuoles in the primitive red alga Cyanidioschyzon merolae
- Author
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Takashi Shimada, Osami Misumi, Yamato Yoshida, Tsuneyoshi Kuroiwa, Fumi Yagisawa, Masaki Yoshida, Takayuki Fujiwara, Mio Ohnuma, Haruko Kuroiwa, and Keiji Nishida
- Subjects
Vesicle ,ATP-binding cassette transporter ,Cell Biology ,Plant Science ,Vacuole ,Biology ,biology.organism_classification ,Cyanidioschyzon merolae ,Biochemistry ,Organelle ,Proteome ,Genetics ,Secretion ,Rab - Abstract
Plant vacuoles are organelles bound by a single membrane, and involved in various functions such as intracellular digestion, metabolite storage, and secretion. To understand their evolution and fundamental mechanisms, characterization of vacuoles in primitive plants would be invaluable. Algal cells often contain polyphosphate-rich compartments, which are thought to be the counterparts of seed plant vacuoles. Here, we developed a method for isolating these vacuoles from Cyanidioschyzon merolae, and identified their proteins by MALDI TOF-MS. The vacuoles were of unexpectedly high density, and were highly enriched at the boundary between 62 and 80% w/v iodixanol by density-gradient ultracentrifugation. The vacuole-containing fraction was subjected to SDS-PAGE, and a total of 46 proteins were identified, including six lytic enzymes, 13 transporters, six proteins for membrane fusion or vesicle trafficking, five non-lytic enzymes, 13 proteins of unknown function, and three miscellaneous proteins. Fourteen proteins were homologous to known vacuolar or lysosomal proteins from seed plants, yeasts or mammals, suggesting functional and evolutionary relationships between C. merolae vacuoles and these compartments. The vacuolar localization of four novel proteins, namely CMP249C (metallopeptidase), CMJ260C (prenylated Rab receptor), CMS401C (ABC transporter) and CMT369C (o-methyltransferase), was confirmed by labeling with specific antibodies or transient expression of hemagglutinin-tagged proteins. The results presented here provide insights into the proteome of C. merolae vacuoles and shed light on their functions, as well as indicating new features.
- Published
- 2009
40. The Bacterial ZapA-like Protein ZED Is Required for Mitochondrial Division
- Author
-
Masaki Yoshida, Osami Misumi, Yamato Yoshida, Haruko Kuroiwa, Mio Ohnuma, Takayuki Fujiwara, Shunsuke Hirooka, Shigeyuki Kawano, and Tsuneyoshi Kuroiwa
- Subjects
Proteomics ,Molecular Sequence Data ,Mitochondrion ,General Biochemistry, Genetics and Molecular Biology ,Homology (biology) ,Bacterial cell structure ,Evolution, Molecular ,Mitochondrial Proteins ,Bacterial Proteins ,Inner membrane ,Amino Acid Sequence ,Plastids ,FtsZ ,Functional similarity ,Genetics ,biology ,Agricultural and Biological Sciences(all) ,Biochemistry, Genetics and Molecular Biology(all) ,Algal Proteins ,Mitochondrial division ,biology.organism_classification ,Mitochondria ,Cell biology ,Cyanidioschyzon merolae ,Rhodophyta ,biology.protein ,CELLBIO ,General Agricultural and Biological Sciences ,Sequence Alignment - Abstract
Summary Bacterial cell division systems that include FtsZ are found throughout prokaryotes [1]. Mitochondria arose from an endosymbiotic α-proteobacterial ancestor and proliferate by division [2–4]. However, how the mitochondrial division system was established from bacterial division is not clear. Here, we have isolated intact mitochondrial division (MD) machineries from the primitive red alga Cyanidioschyzon merolae and identified a bacterial ZapA-like protein, ZED, that constricts the basal structure of MD machinery with FtsZ. ZED contains a predicted mitochondrial transit signal and two coiled-coil regions and has partial homology with the bacterial division protein ZapA [5]. Cytological studies revealed that ZED accumulates to form a ring structure that colocalizes with FtsZ beneath the inner membrane. ZED proteins are expressed just before mitochondrial division. The short-form ZED (S-ZED) then appears at the mitochondrial constriction phase. Protein-protein interaction analysis and transient expression of antisense against ZED showed that S-ZED interacts with FtsZ1 to constitute the basal structure of the MD machinery and is required for mitochondrial division. We also demonstrate compelling functional similarity between bacterial ZapA and mitochondrial ZED, suggesting that the bacterial cell division system was incorporated into the MD machinery with remodeling of bacterial division proteins during evolution.
- Published
- 2009
- Full Text
- View/download PDF
41. Periodic Gene Expression Patterns during the Highly Synchronized Cell Nucleus and Organelle Division Cycles in the Unicellular Red Alga Cyanidioschyzon merolae
- Author
-
Osami Misumi, Toshiyuki Mori, Keiji Nishida, Fumi Yagisawa, Masaki Yoshida, Kan Tanaka, Yamato Yoshida, Kousuke Tashiro, Haruko Kuroiwa, Sousuke Imamura, Tsuneyoshi Kuroiwa, and Takayuki Fujiwara
- Subjects
organelle division genes ,Cell division ,Cyanidioschyzon merolae ,Gene Expression ,Vacuole ,mitochondria–plastid division genes ,symbols.namesake ,Organelle ,Genetics ,medicine ,Plastids ,Plastid ,Molecular Biology ,Cell Nucleus ,Organelles ,biology ,Algal Proteins ,Cell Cycle ,General Medicine ,Golgi apparatus ,Cell cycle ,Full Papers ,biology.organism_classification ,Cell biology ,Mitochondria ,Cell nucleus ,medicine.anatomical_structure ,Rhodophyta ,symbols ,microarray ,Cell Division - Abstract
Previous cell cycle studies have been based on cell-nuclear proliferation only. Eukaryotic cells, however, have double membranes-bound organelles, such as the cell nucleus, mitochondrion, plastids and single-membrane-bound organelles such as ER, the Golgi body, vacuoles (lysosomes) and microbodies. Organelle proliferations, which are very important for cell functions, are poorly understood. To clarify this, we performed a microarray analysis during the cell cycle of Cyanidioschyzon merolae. C. merolae cells contain a minimum set of organelles that divide synchronously. The nuclear, mitochondrial and plastid genomes were completely sequenced. The results showed that, of 158 genes induced during the S or G2-M phase, 93 were known and contained genes related to mitochondrial division, ftsZ1-1, ftsz1-2 and mda1, and plastid division, ftsZ2-1, ftsZ2-2 and cmdnm2. Moreover, three genes, involved in vesicle trafficking between the single-membrane organelles such as vps29 and the Rab family protein, were identified and might be related to partitioning of single-membrane-bound organelles. In other genes, 46 were hypothetical and 19 were hypothetical conserved. The possibility of finding novel organelle division genes from hypothetical and hypothetical conserved genes in the S and G2-M expression groups is discussed.
- Published
- 2009
42. Transient gene suppression in a red alga, Cyanidioschyzon merolae 10D
- Author
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Kan Tanaka, Mio Ohnuma, Satoru Watanabe, Osami Misumi, Tsuneyoshi Kuroiwa, and Takayuki Fujiwara
- Subjects
Regulation of gene expression ,Expression vector ,biology ,RNA ,Cell Biology ,Plant Science ,General Medicine ,biology.organism_classification ,Catalase ,Molecular biology ,Immunohistochemistry ,Gene Expression Regulation, Enzymologic ,Green fluorescent protein ,Antisense RNA ,Transformation (genetics) ,Cyanidioschyzon merolae ,Rhodophyta ,RNA, Antisense ,Gene - Abstract
Antisense suppression is a powerful tool to analyze gene function. In this study, we show that antisense RNA suppressed the expression of a target gene in the unicellular red alga, Cyanidioschyzon merolae. In this study, the antisense strand of the catalase gene was cloned and inserted into an expression vector upstream of the GFP gene. This plasmid was introduced into C. merolae cells using a polyethylene glycol-mediated transformation protocol. Using the expression of GFP as a marker of transformed cells, the expression of catalase was examined by immunocytochemistry. Decreased expression of catalase was observed in cells that were transformed with the antisense strand of the catalase gene. These results indicate the utility of this antisense suppression system.
- Published
- 2009
43. Stereoinversion of 1-arylethanols by Cyanidioschyzon merolae NEIS-1332
- Author
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C. Akira Horiuchi, Tsuneyoshi Kuroiwa, Masayuki Kuniyoshi, Takamitsu Utsukihara, Masahiro Koshimura, Osami Misumi, and Koichi Nakajima
- Subjects
chemistry.chemical_classification ,Ethanol ,biology ,Stereochemistry ,Chemistry ,Process Chemistry and Technology ,Bioengineering ,biology.organism_classification ,Biochemistry ,Catalysis ,chemistry.chemical_compound ,Cyanidioschyzon merolae ,Biotransformation ,Yield (chemistry) ,Alkyl - Abstract
The stereoinversion of ortho-, meta- and para-substituted fluoro, chloro, bromo and methyl 1-phenylethanols using red alga (Cyanidioschyzon merolae) was investigated. It was found that 1-(4′-chlorophenyl)ethanol (1f) gave the corresponding (S)-alcohols in high ee and high yield (95%, 91% ee). On the other hand, stereoinversion of 1-(3′-chlorophenyl)ethanol (1e) indicated moderate ee (1e, 54% ee). In the case of 1-(2′-chlorophenyl)ethanol (1d), the biotransformation did not proceed. Moreover, we discuss about stereoinversion of alkyl group for secondary alcohols (3a–3d) and cis-2-methylcyclohexanol.
- Published
- 2008
44. Microarray Analysis Reveals S-Adenosylmethionine (SAM) Synthetase Involvement in Salt Tolerance of Cyanidioschyzon merolae
- Author
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Kosuke Tashiro, Takayuki Sakajiri, Tsuneyoshi Kuroiwa, Shunsuke Hirooka, Takayuki Fujiwara, Osami Misumi, and Keita Asano
- Subjects
Genetics ,biology ,Microarray analysis techniques ,Cell Biology ,Plant Science ,biology.organism_classification ,Hsp70 ,Chloroplast ,Cyanidioschyzon merolae ,Biochemistry ,Heat shock protein ,Extreme environment ,Arabidopsis thaliana ,Animal Science and Zoology ,Gene - Abstract
We searched for candidate genes for producing salt tolerant plants from the red alga Cyanidioschyzon merolae, which lives in an extreme environment (hot springs). Arabidopsis thaliana plants die under 0.1 M salt culture, whereas the red algal cells survived under 0.3 M salt for 7 d. However, their chloroplasts changed from green to white and they soon died under 0.4 M, which is the concentration of seawater. Genes that were selectively expressed at 2 h and 24 h in 0.3 M salt concentrations were examined by microarray analysis. Under salt stress, the numbers of highly expressed genes at 2 h increased from 70 to 95 after culture for 24 h. The highly expressed genes included those encoding proteins similar to low molecular weight heat shock proteins, heat shock protein 70, and S-adenosylmethionine (SAM) synthetase. On the base of the present data and on the known metabolic functions of the proteins, we suggest that the SAM synthetase gene from C. merolae is a candidate gene for genetic engineering to produce salt tolerance plants.
- Published
- 2008
45. Cytological Studies of Metal Ion Tolerance in the Red Algae Cyanidioschyzon merolae
- Author
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Osami Misumi, Takayuki Sakajiri, Syunsuke Hirooka, Tsuneyoshi Kuroiwa, and Haruko Kuroiwa
- Subjects
chemistry.chemical_classification ,biology ,Metal ions in aqueous solution ,Cell Biology ,Plant Science ,Vacuole ,Red algae ,biology.organism_classification ,Divalent ,Metal ,Chloroplast ,Cyanidioschyzon merolae ,chemistry ,visual_art ,Botany ,Genetics ,visual_art.visual_art_medium ,Animal Science and Zoology ,Viability assay ,Nuclear chemistry - Abstract
The unicellular red alga Cyanidioschyzon merolae is tolerant of high levels of several different metal ions. Cells of the alga cultured with divalent or trivalent metal ions at 10 mM contained elevated concentrations of each metal. The highest tolerance was shown for Al followed by Fe, Cu>Ni>Zn>Mn. The viability and morphology of the cells were investigated for different periods of time after metal addition. In contrast to land plants, C. merolae exhibited a very high tolerance to metal ions, but the response varied according to the metal ion added. In particular, Mn, Zn and Ni ions affected the structure and function of the chloroplast, and markedly reduced the cell viability. Nevertheless, the tolerance of C. merolae to metal ions is the highest among reported eukaryotic cells. Cellular mechanisms for detoxification or defense against metal ions must be well developed in this alga.
- Published
- 2008
46. MORPHOLOGICAL CHANGES IN MITOCHONDRIAL AND CHLOROPLAST NUCLEOIDS AND MITOCHONDRIA DURING THE CHLAMYDOMONAS REINHARDTII (CHLOROPHYCEAE) CELL CYCLE
- Author
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Takayoshi Hiramatsu, Soichi Nakamura, Osami Misumi, and Tsuneyoshi Kuroiwa
- Subjects
Mitochondrial DNA ,animal structures ,Chloroplast nucleoid ,biology ,Cell division ,fungi ,Chlamydomonas ,Chlamydomonas reinhardtii ,Plant Science ,Aquatic Science ,biology.organism_classification ,Cell biology ,Chloroplast ,Chloroplast DNA ,bacteria ,Nucleoid - Abstract
Morphological changes in the organellar nucleoids and mitochondria of living Chlamydomonas reinhardtii Dang were examined during the cell cycle under conditions of 12:12 light:dark. The nucleoids were stained with SYBR-Green I, and the mitochondria were stained with 3,3-dihexylo-xacarbocyanine iodide. An mocG33 mutant, which contains one large chloroplast nucleoid throughout the cell cycle, was used to distinguish between the mitochondrial and chloroplast nucleoids. Changes in the total levels of organellar DNA levels were assessed by real-time PCR. Each of the G 1 , S, M, and Smt, cp phases was estimated. At the start of the light period, the new daughter cells were in G 1 and contained about 30 mitochondrial and 10 chloroplast nucleoids, which were dispersed and had diameters of 0.1 and 0.2 μm, respectively. During the G 1 phase of the light period, and at the start of the S phase, both nucleoids formed short thread-like or bead-like structures, probably divided, and increased continuously in number, concomitantly with DNA synthesis. The nucleoids probably became smaller due to the decrease in DNA of each particle and were indistinguishable. The cells in the S and M phases contained extremely high numbers of scattered nucleoids. However, in the G 1 phase of the dark period, the nucleoids again formed short thread-like or bead-like structures, probably fused, and decreased in number. The mitochondria appeared as tangled sinuous structures that extended throughout the cytoplasm and resembled a single large mitochondrion. During the cell cycle, the numbers of mitochondrial nucleoids and sinuous structures varied relative to one another.
- Published
- 2006
47. Isolated Chloroplast Division Machinery Can Actively Constrict After Stretching
- Author
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Haruko Kuroiwa, Osami Misumi, Keiji Nishida, Fumi Yagisawa, Yamato Yoshida, Hideaki Nanamiya, Takayuki Fujiwara, Tsuneyoshi Kuroiwa, and Fujio Kawamura
- Subjects
Dynamins ,Chloroplasts ,Multidisciplinary ,biology ,Algal Proteins ,Chloroplast division ,Intracellular Membranes ,biology.organism_classification ,GTP Phosphohydrolases ,Protein filament ,Chloroplast ,Actin Cytoskeleton ,Cyanidioschyzon merolae ,Optical tweezers ,Rhodophyta ,Botany ,biology.protein ,Biophysics ,Microscopy, Immunoelectron ,FtsZ ,Dynamin - Abstract
Chloroplast division involves plastid-dividing, dynamin, and FtsZ (PDF) rings. We isolated intact supertwisted (or spiral) and circular PDF machineries from chloroplasts of the red alga Cyanidioschyzon merolae . After individual intact PDF machineries were stretched to four times their original lengths with optical tweezers, they spontaneously returned to their original sizes. Dynamin-released PDF machineries did not retain the spiral structure and could not be stretched. Thus, dynamin may generate the motive force for contraction by filament sliding in dividing chloroplasts, in addition to pinching-off the membranes.
- Published
- 2006
48. Reduction of various ketones by red algae
- Author
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Takamitsu Utsukihara, C. Akira Horiuchi, Osami Misumi, Nakahide Kato, and Tsuneyoshi Kuroiwa
- Subjects
biology ,Stereochemistry ,Organic Chemistry ,General Medicine ,Cyanidium caldarium ,Red algae ,biology.organism_classification ,Medicinal chemistry ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,Cyanidioschyzon merolae ,chemistry ,Yield (chemistry) ,Stereoselectivity ,Physical and Theoretical Chemistry ,Acetophenone - Abstract
The reduction of acetophenone derivatives, (+)- and (−)-camphorquinones and steroidal ketones using red algae ( Cyanidioschyzon merolae 10D and Cyanidium caldarium ) was investigated. It was found that fluoro, chloro and bromo acetophenone derivatives 1a – i were reduced with good enantioselectivity. On the contrary, reduction of methyl and methoxy acetophenone 1j – o showed low enantioselectivity. The reduction followed Prelog’s rule, giving the ( S )-alcohols in all cases. Moreover, (+)- camphorquinone 5a was reduced to give (−)-3 S - exo -hydroxycamphor 5d as the major product with high stereoselectivity in high yield. In addition, it was found that reduction of 5α-androstane-3,17-dione 8a gave the 3α-OH isomer (3α-OH/3β-OH = 76/24) with high stereoselectivity. Overall it was found that C. merolae and C. caldarium were able to reduce various substrates.
- Published
- 2006
49. Algae sense exact temperatures: small heat shock proteins are expressed at the survival threshold temperature in Cyanidioschyzon merolae and Chlamydomonas reinhardtii
- Author
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Yoshiki Nishimura, Takayuki Fujiwara, Mami Nakamura, Osami Misumi, Tsuneyoshi Kuroiwa, Naomi Harada, Yusuke Kobayashi, and Takafumi Saito
- Subjects
Inverted repeat ,Molecular Sequence Data ,Chlamydomonas reinhardtii ,Algae ,Gene Expression Regulation, Plant ,Genetics ,HSP ,Amino Acid Sequence ,unicellular algae ,environmental adaptation ,Gene ,Ecology, Evolution, Behavior and Systematics ,Phylogeny ,Plant Proteins ,biology ,Microarray analysis techniques ,heat resistance ,Chlamydomonas ,Structural gene ,Temperature ,biology.organism_classification ,Cell biology ,Heat-Shock Proteins, Small ,Cyanidioschyzon merolae ,microarray ,Research Article - Abstract
The primitive red alga Cyanidioschyzon merolae inhabits acidic hot springs and shows robust resistance to heat shock treatments up to 63 °C. Microarray analysis was performed to identify the key genes underlying the high temperature tolerance of this organism. Among the upregulated genes that were identified, we focused on two small heat shock proteins (sHSPs) that belong to a unique class of HSP families. These two genes are located side by side in an inverted repeat orientation on the same chromosome and share a promoter. These two genes were simultaneously and rapidly upregulated in response to heat shock treatment (>1,000-fold more than the control). Interestingly, upregulation appeared to be triggered not by a difference in temperatures, but rather by the absolute temperature. Similar sHSP structural genes have been reported in the green alga Chlamydomonas reinhardtii, but the threshold temperature for the expression of these sHSP-encoding genes in Ch. reinhardtii was different from the threshold temperature for the expression of the sHSP genes from Cy. merolae. These results indicate the possible importance of an absolute temperature sensing system in the evolution and tolerance of high-temperature conditions among unicellular microalgae.
- Published
- 2014
50. PHYLOGENETIC IMPLICATIONS OF THE CAD COMPLEX FROM THE PRIMITIVE RED ALGA CYANIDIOSCHYZON MEROLAE (CYANIDIALES, RHODOPHYTA)1
- Author
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Tsuneyoshi Kuroiwa, Tetsuya Higashiyama, Osami Misumi, Hisayoshi Nozaki, Haruko Kuroiwa, and Motomichi Matsuzaki
- Subjects
Genetics ,Aspartate carbamoyltransferase ,Cyanidioschyzon merolae ,Dihydroorotase ,biology ,Phylogenetic tree ,Phylogenetics ,Horizontal gene transfer ,Orotate phosphoribosyltransferase ,Plant Science ,Aquatic Science ,biology.organism_classification ,Amoebozoa - Abstract
The de novo pyrimidine biosynthetic pathway consists of six enzymes: carbamoyl-phosphate synthetase II (CPS II), aspartate carbamoyltransferase (ACT), dihydroorotase (DHO), dihydroorotate dehydrogenase, orotate phosphoribosyltransferase, and orotidine-5′-monophosphate decarboxylase. The origin and organization of the first three enzymes differ markedly between Opisthokonta (Metazoa and Fungi) and the Amoebozoa and green plants. However, no information has been available regarding the characteristics of such genes in other photosynthetic eukaryotes. In this study, we examined the pyrimidine biosynthetic cluster in the primitive red alga Cyanidioschyzon merolae P. DeLuca et al. isolate 10D. Unlike the situation in green plants, the CPS II, ACT, and DHO of C. merolae were fused to form a single open reading frame (the CAD complex), as in the Opisthokonta and Amoebozoa. Phylogenetic analysis of the CPS domain sequences suggested that this red algal CAD complex did not result from a recent lateral gene transfer from Metazoa or Fungi but that the fusion of the three genes occurred before the divergence of Opisthokonta, Amoebozoa, and the red algae. These results cast doubt on the recent hypothesis that the Opisthokonta and Amoebozoa form a monophyletic group, based on the presence in both of the CAD complex.
- Published
- 2005
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