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Hisayoshi Nozaki - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Two Different Rickettsial Bacteria Invading
2016Co-Authors: Volvox Carteri, Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Background Bacteria of the family Rickettsiaceae are principally associated with arthropods. Recently, endosymbionts of the Rickettsiaceae have been found in non-phagotrophic cells of the vol-vocalean green algae Carteria cerasiformis, Pleodorina japonica, and Volvox carteri. Such endosymbionts were present in only C. cerasiformis strain NIES-425 and V. carteri strain UTEX 2180, of various strains of Carteria and V. carteri examined, suggesting that rickettsial endosymbionts may have been transmitted to only a few algal strains very recently. Howev-er, in preliminary work, we detected a sequence similar to that of a rickettsial gene in the nu-clear genome of V. carteri strain EVE. Methodology/Principal Findings Here we explored the origin of the rickettsial gene-like sequences in the endosymbiont-lack-ing V. carteri strain EVE, by performing comparative analyses on 13 strains of V. carteri. By reference to our ongoing genomic sequence of rickettsial endosymbionts in C. cerasiformis strain NIES-425 cells, we confirmed that an approximately 9-kbp DNA sequence encom-passing a region similar to that of four rickettsial genes was present in the nuclear genome of V. carteri strain EVE. Phylogenetic analyses, and comparisons of the synteny of rickettsi-al gene-like sequences from various strains of V. carteri, indicated that the rickettsial gene-like sequences in the nuclear genome of V. carteri strain EVE were closely related to rickett-sial gene sequences of P. japonica, rather than those of V. carteri strain UTEX 2180
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two different rickettsial bacteria invading volvox carteri
PLOS ONE, 2015Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Background Bacteria of the family Rickettsiaceae are principally associated with arthropods. Recently, endosymbionts of the Rickettsiaceae have been found in non-phagotrophic cells of the volvocalean green algae Carteria cerasiformis, Pleodorina japonica, and Volvox carteri. Such endosymbionts were present in only C. cerasiformis strain NIES-425 and V. carteri strain UTEX 2180, of various strains of Carteria and V. carteri examined, suggesting that rickettsial endosymbionts may have been transmitted to only a few algal strains very recently. However, in preliminary work, we detected a sequence similar to that of a rickettsial gene in the nuclear genome of V. carteri strain EVE. Methodology/Principal Findings Here we explored the origin of the rickettsial gene-like sequences in the endosymbiont-lacking V. carteri strain EVE, by performing comparative analyses on 13 strains of V. carteri. By reference to our ongoing genomic sequence of rickettsial endosymbionts in C. cerasiformis strain NIES-425 cells, we confirmed that an approximately 9-kbp DNA sequence encompassing a region similar to that of four rickettsial genes was present in the nuclear genome of V. carteri strain EVE. Phylogenetic analyses, and comparisons of the synteny of rickettsial gene-like sequences from various strains of V. carteri, indicated that the rickettsial gene-like sequences in the nuclear genome of V. carteri strain EVE were closely related to rickettsial gene sequences of P. japonica, rather than those of V. carteri strain UTEX 2180. Conclusion/Significance At least two different rickettsial organisms may have invaded the V. carteri lineage, one of which may be the direct ancestor of the endosymbiont of V. carteri strain UTEX 2180, whereas the other may be closely related to the endosymbiont of P. japonica. Endosymbiotic gene transfer from the latter rickettsial organism may have occurred in an ancestor of V. carteri. Thus, the rickettsiae may be widely associated with V. carteri, and likely have often been lost during host evolution.
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Rickettsial genes and gene-like sequences in the genomes of Volvox carteri and rickettsial possible endosymbionts.
2015Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Schematic representations of arrangements/synteny of several rickettsial genes and gene-like sequences present in DNA of the nuclear genome of V. carteri (A) and in the genomes of rickettsial possible endosymbionts harbored by three volvocalean species (B-D). Coding DNA sequences (CDSs) and CDS-like regions are shown as boxes. Rickettsial CDSs/CDS-like regions are shown in pale yellow, the V. carteri transposon Jordan-like region in green and others in black. Placement of boxes above/below the line indicates gene direction (from left-to-right or right-to-left, respectively). Black double-headed arrows on the baseline indicate the regions sequenced in the present study. Colored triangles under boxes indicate the locations of primers used for semi-quantitative genomic PCR (16S rRNA gene 5′-region: magenta, 16S rRNA gene 3′-region: light blue, murB: orange, ddlB: green; Fig. 2E). For accession numbers of sequences used in this figure, see S3 Table. (A) Part of scaffold 6 of the V. carteri f. nagariensis strain EVE nuclear genome. (B) Part of the Carteria cerasiformis NIES-425 draft endosymbiont genome, including 16S rRNA (first line) and murB-ftsQ (second line). White triangles indicate primers used to amplify the sequencing templates (ccmF-R02 and phbB-F01; see Materials and Methods). (C) Part of the genome of a possible endosymbiont of V. carteri f. weismannia strain UTEX 2180, including murB and ddlB (right). The 16S rRNA gene of the endosymbiont [12] is also shown (left). (D) Part of the genome of a possible endosymbiont of Pleodorina japonica strain NIES-577, including murB and ddlB (right). The 16S rRNA gene [11] is also shown (left).
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a rickettsial endosymbiont inhabiting the cytoplasm of volvox carteri volvocales chlorophyceae
Phycologia, 2014Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Hisayoshi NozakiAbstract:A bacterial endosymbiont was previously observed in the green alga Volvox carteri strain UTEX 2180 using transmission electron microscopy, although its phylogenetic status was unknown. Here, we identified the bacterial endosymbiont based on analyses of the 16S ribosomal RNA (rRNA) gene. The endosymbiont of V. carteri belongs to the “hydra group” characterized by non-arthropod hosts, within the eubacterial family Rickettsiaceae (Rickettsiales; Alphaproteobacteria). In the hydra group, the endosymbiont formed a clade with the endosymbionts of the volvocaleans Carteria cerasiformis and Pleodorina japonica and the ciliate Diophrys appendiculata but was separated from the endosymbionts of marine green macroalgae (Bryopsis spp.). Fluorescence in situ hybridization using a probe specific for the 16S rRNA of the V. carteri endosymbiont confirmed our molecular identification and the distribution of the endosymbiont within the host cytoplasm. Rickettsial endosymbionts were not detected in eight other strains of V. ...
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Origin of Female/Male Gender as Deduced by the Mating-Type Loci of the Colonial Volvocalean Greens
Sexual Reproduction in Animals and Plants, 2014Co-Authors: Hisayoshi NozakiAbstract:Colonial Volvocales (green algae) are a model lineage for the study of the evolution of sexual reproduction because isogamy, anisogamy, and oogamy are recognized within the closely related group, and several mating type (sex)-specific genes were identified in the closely related unicellular Chlamydomonas reinhardtii during the past century. In 2006, we first identified a sex-specific gene within the colonial Volvocales using the anisogamous colonial volvocalean alga Pleodorina starrii, namely, a male-specific gene called “OTOKOGI,” which is a homologue of the minus mating type-determining gene MID of the isogamous C. reinhardtii. Thus, it was speculated that the derived or minus mating type of C. reinhardtii is homologous to the male in the anisogamous/oogamous members of the colonial Volvocales. The discovery of the male-specific gene facilitated comparative studies of the mating-type locus (MT) (primitive sex chromosomal region) because it must be localized in MT. Recently, our international research group determined the genome sequence of MT in the oogamous Volvox carteri. V. carteri MT shows remarkable expansion and divergence relative to that from C. reinhardtii. Five new female-limited “HIBOTAN” genes and ten male-limited genes (including “OTOKOGI”) were identified in V. carteri MT. These observations suggest that the origins of femaleness and maleness are principally affected by the evolution of MT, which has undergone a remarkable expansion and gain of new male- and female-limited genes. Our recent results regarding the evolution of the volvocalean MT gene MAT3/RB are also discussed in relationship to the evolution of male–female sexual dimorphism.
Kaoru Kawafune - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Two Different Rickettsial Bacteria Invading
2016Co-Authors: Volvox Carteri, Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Background Bacteria of the family Rickettsiaceae are principally associated with arthropods. Recently, endosymbionts of the Rickettsiaceae have been found in non-phagotrophic cells of the vol-vocalean green algae Carteria cerasiformis, Pleodorina japonica, and Volvox carteri. Such endosymbionts were present in only C. cerasiformis strain NIES-425 and V. carteri strain UTEX 2180, of various strains of Carteria and V. carteri examined, suggesting that rickettsial endosymbionts may have been transmitted to only a few algal strains very recently. Howev-er, in preliminary work, we detected a sequence similar to that of a rickettsial gene in the nu-clear genome of V. carteri strain EVE. Methodology/Principal Findings Here we explored the origin of the rickettsial gene-like sequences in the endosymbiont-lack-ing V. carteri strain EVE, by performing comparative analyses on 13 strains of V. carteri. By reference to our ongoing genomic sequence of rickettsial endosymbionts in C. cerasiformis strain NIES-425 cells, we confirmed that an approximately 9-kbp DNA sequence encom-passing a region similar to that of four rickettsial genes was present in the nuclear genome of V. carteri strain EVE. Phylogenetic analyses, and comparisons of the synteny of rickettsi-al gene-like sequences from various strains of V. carteri, indicated that the rickettsial gene-like sequences in the nuclear genome of V. carteri strain EVE were closely related to rickett-sial gene sequences of P. japonica, rather than those of V. carteri strain UTEX 2180
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two different rickettsial bacteria invading volvox carteri
PLOS ONE, 2015Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Background Bacteria of the family Rickettsiaceae are principally associated with arthropods. Recently, endosymbionts of the Rickettsiaceae have been found in non-phagotrophic cells of the volvocalean green algae Carteria cerasiformis, Pleodorina japonica, and Volvox carteri. Such endosymbionts were present in only C. cerasiformis strain NIES-425 and V. carteri strain UTEX 2180, of various strains of Carteria and V. carteri examined, suggesting that rickettsial endosymbionts may have been transmitted to only a few algal strains very recently. However, in preliminary work, we detected a sequence similar to that of a rickettsial gene in the nuclear genome of V. carteri strain EVE. Methodology/Principal Findings Here we explored the origin of the rickettsial gene-like sequences in the endosymbiont-lacking V. carteri strain EVE, by performing comparative analyses on 13 strains of V. carteri. By reference to our ongoing genomic sequence of rickettsial endosymbionts in C. cerasiformis strain NIES-425 cells, we confirmed that an approximately 9-kbp DNA sequence encompassing a region similar to that of four rickettsial genes was present in the nuclear genome of V. carteri strain EVE. Phylogenetic analyses, and comparisons of the synteny of rickettsial gene-like sequences from various strains of V. carteri, indicated that the rickettsial gene-like sequences in the nuclear genome of V. carteri strain EVE were closely related to rickettsial gene sequences of P. japonica, rather than those of V. carteri strain UTEX 2180. Conclusion/Significance At least two different rickettsial organisms may have invaded the V. carteri lineage, one of which may be the direct ancestor of the endosymbiont of V. carteri strain UTEX 2180, whereas the other may be closely related to the endosymbiont of P. japonica. Endosymbiotic gene transfer from the latter rickettsial organism may have occurred in an ancestor of V. carteri. Thus, the rickettsiae may be widely associated with V. carteri, and likely have often been lost during host evolution.
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Rickettsial genes and gene-like sequences in the genomes of Volvox carteri and rickettsial possible endosymbionts.
2015Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Schematic representations of arrangements/synteny of several rickettsial genes and gene-like sequences present in DNA of the nuclear genome of V. carteri (A) and in the genomes of rickettsial possible endosymbionts harbored by three volvocalean species (B-D). Coding DNA sequences (CDSs) and CDS-like regions are shown as boxes. Rickettsial CDSs/CDS-like regions are shown in pale yellow, the V. carteri transposon Jordan-like region in green and others in black. Placement of boxes above/below the line indicates gene direction (from left-to-right or right-to-left, respectively). Black double-headed arrows on the baseline indicate the regions sequenced in the present study. Colored triangles under boxes indicate the locations of primers used for semi-quantitative genomic PCR (16S rRNA gene 5′-region: magenta, 16S rRNA gene 3′-region: light blue, murB: orange, ddlB: green; Fig. 2E). For accession numbers of sequences used in this figure, see S3 Table. (A) Part of scaffold 6 of the V. carteri f. nagariensis strain EVE nuclear genome. (B) Part of the Carteria cerasiformis NIES-425 draft endosymbiont genome, including 16S rRNA (first line) and murB-ftsQ (second line). White triangles indicate primers used to amplify the sequencing templates (ccmF-R02 and phbB-F01; see Materials and Methods). (C) Part of the genome of a possible endosymbiont of V. carteri f. weismannia strain UTEX 2180, including murB and ddlB (right). The 16S rRNA gene of the endosymbiont [12] is also shown (left). (D) Part of the genome of a possible endosymbiont of Pleodorina japonica strain NIES-577, including murB and ddlB (right). The 16S rRNA gene [11] is also shown (left).
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a rickettsial endosymbiont inhabiting the cytoplasm of volvox carteri volvocales chlorophyceae
Phycologia, 2014Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Hisayoshi NozakiAbstract:A bacterial endosymbiont was previously observed in the green alga Volvox carteri strain UTEX 2180 using transmission electron microscopy, although its phylogenetic status was unknown. Here, we identified the bacterial endosymbiont based on analyses of the 16S ribosomal RNA (rRNA) gene. The endosymbiont of V. carteri belongs to the “hydra group” characterized by non-arthropod hosts, within the eubacterial family Rickettsiaceae (Rickettsiales; Alphaproteobacteria). In the hydra group, the endosymbiont formed a clade with the endosymbionts of the volvocaleans Carteria cerasiformis and Pleodorina japonica and the ciliate Diophrys appendiculata but was separated from the endosymbionts of marine green macroalgae (Bryopsis spp.). Fluorescence in situ hybridization using a probe specific for the 16S rRNA of the V. carteri endosymbiont confirmed our molecular identification and the distribution of the endosymbiont within the host cytoplasm. Rickettsial endosymbionts were not detected in eight other strains of V. ...
Makoto M. Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Morphology and sexual reproduction ofCarteria palmatasp. nov. belonging to theCarteriagroup IsensuLembi (Chlorophyceae, Volvocales)
Phycologia, 2005Co-Authors: Shoichiro Suda, Hisayoshi Nozaki, Makoto M. WatanabeAbstract:Abstract Carteria palmata Suda, Nozaki & M.M. Watanabe sp. nov. from Japan has been examined by light and electron microscopy using cultured materials. The cells are nearly spherical, 16–22 µm long, and 15–21 µm wide. The chloroplast is single and stellate cup-shaped, containing a basal and palm-shaped pyrenoid without coherent starch grains. The pyrenoid matrix is traversed by reticulated chloroplast thylakoid lamellae, and there is no clear border between the pyrenoid matrix and the chloroplast stroma. In the chloroplast, many microtubule-like structures exist around the pyrenoid. A conspicuous eyespot is located in the middle to anterior surface of the chloroplast. Four contractile vacuoles are located in the anterior cytoplasm under the flagellar bases. The flagellar apparatus is arranged similarly to the Carteria group I type, which has eight connecting fibres, each interlinking two adjacent basal bodies at the distal and proximal ends. In addition to these fibres, one distal connecting fibre interli...
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PHYLOGENETIC ANALYSIS OF MORPHOLOGICAL SPECIES OF Carteria (VOLVOCALES, CHLOROPHYTA) BASED ON RBCL GENE SEQUENCES
Journal of Phycology, 1997Co-Authors: Hisayoshi Nozaki, Motomi Ito, Makoto M. Watanabe, Hiroyoshi Takano, Tsuneyoshi KuroiwaAbstract:Four related species in the unicellular volvocalean genus Carteria [C. crucifera Pascher, C. eugametos Mitra, C. inversa (Korshikov) Bourrelly and C. cerasiformis Nozaki et al.] were delineated on the basis of recent comparative light and electron microscopy of a large number of culture strains. However, the species thus delineated may not represent natural or monophyletic entities. In the present study, 1128 base pairs of the chloroplast protein-coding gene (large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase gene) from 12 Carteria strains representing the four species as well as from related volvocalean species were analyzed to elucidate the phylogenetic status of the taxonomic or morphologic species of Carteria. The sequence data showed that the 12 Carteria strains exhibit four robust monophyletic groups which are strictly consistent with the four taxonomic species. These results are discussed in relation to contrasting results found in other microalgal genera. It is concluded that phylogenetic analysis, based on DMA sequence data and comparative morphologic characterization of species and using a large number of culture strains, is essential to a natural system of microalgal species taxonomy.
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LIGHT AND ELECTRON MICROSCOPY OF GRAZING BY POTERIOOCHROMONAS MALHAMENSIS (CHRYSOPHYCEAE) ON A RANGE OF PHYTOPLANKTON TAXA1
Journal of Phycology, 1996Co-Authors: Xiaoming Zhang, Makoto M. Watanabe, Isao InouyeAbstract:Grazing of fluorescent latex beads, bacteria, and various species of phytoplankton by Poterioochromonas malhamensis (Pringsheim) Peterfi (about 8.0 μm in diameter) was surveyed. The alga ingested fluorescent beads and various live or killed and nomnotile or motile organisms including bacteria, blue-green algae, green algae, diatoms, and chrysomonads. The size range of grazed prey was from 0.1 to 6.0 μm for latex beads and from 1.0 μm (bacteria) to about 21 μm (Carteria inverse) for organisms. As many as 17 latex beads (2.0 μm) or more than 10 Microcystis cells (5–6 μm) were ingested by a single P. malhamensis cell. Following such grazing, the cell increased in volume by up to about 30-fold. The range of cell volume of ingested prey was from 0.52 μm3 (bacteria) to about 3178 μm3(Carteria inversa). This study demonstrates for the first time that P. malhamensis is capable of grazing algae 2–3 times larger in diameter than its own cell and of grazing intact motile algae. Poterioochromonas malhamensis is an omnivorous grazer. Food vacuole formation and digestion processes were examined. The membrane that was derived from the plasma membrane and surrounded the prey disappeared sometime after ingestion. The food vacuole was then formed by successive fusion of numerous homogeneous vesicles accumulated around the prey. The prey was enclosed in a single membrane-bound food vacuole and then digested.
Yuichi Hongoh - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Two Different Rickettsial Bacteria Invading
2016Co-Authors: Volvox Carteri, Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Background Bacteria of the family Rickettsiaceae are principally associated with arthropods. Recently, endosymbionts of the Rickettsiaceae have been found in non-phagotrophic cells of the vol-vocalean green algae Carteria cerasiformis, Pleodorina japonica, and Volvox carteri. Such endosymbionts were present in only C. cerasiformis strain NIES-425 and V. carteri strain UTEX 2180, of various strains of Carteria and V. carteri examined, suggesting that rickettsial endosymbionts may have been transmitted to only a few algal strains very recently. Howev-er, in preliminary work, we detected a sequence similar to that of a rickettsial gene in the nu-clear genome of V. carteri strain EVE. Methodology/Principal Findings Here we explored the origin of the rickettsial gene-like sequences in the endosymbiont-lack-ing V. carteri strain EVE, by performing comparative analyses on 13 strains of V. carteri. By reference to our ongoing genomic sequence of rickettsial endosymbionts in C. cerasiformis strain NIES-425 cells, we confirmed that an approximately 9-kbp DNA sequence encom-passing a region similar to that of four rickettsial genes was present in the nuclear genome of V. carteri strain EVE. Phylogenetic analyses, and comparisons of the synteny of rickettsi-al gene-like sequences from various strains of V. carteri, indicated that the rickettsial gene-like sequences in the nuclear genome of V. carteri strain EVE were closely related to rickett-sial gene sequences of P. japonica, rather than those of V. carteri strain UTEX 2180
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two different rickettsial bacteria invading volvox carteri
PLOS ONE, 2015Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Background Bacteria of the family Rickettsiaceae are principally associated with arthropods. Recently, endosymbionts of the Rickettsiaceae have been found in non-phagotrophic cells of the volvocalean green algae Carteria cerasiformis, Pleodorina japonica, and Volvox carteri. Such endosymbionts were present in only C. cerasiformis strain NIES-425 and V. carteri strain UTEX 2180, of various strains of Carteria and V. carteri examined, suggesting that rickettsial endosymbionts may have been transmitted to only a few algal strains very recently. However, in preliminary work, we detected a sequence similar to that of a rickettsial gene in the nuclear genome of V. carteri strain EVE. Methodology/Principal Findings Here we explored the origin of the rickettsial gene-like sequences in the endosymbiont-lacking V. carteri strain EVE, by performing comparative analyses on 13 strains of V. carteri. By reference to our ongoing genomic sequence of rickettsial endosymbionts in C. cerasiformis strain NIES-425 cells, we confirmed that an approximately 9-kbp DNA sequence encompassing a region similar to that of four rickettsial genes was present in the nuclear genome of V. carteri strain EVE. Phylogenetic analyses, and comparisons of the synteny of rickettsial gene-like sequences from various strains of V. carteri, indicated that the rickettsial gene-like sequences in the nuclear genome of V. carteri strain EVE were closely related to rickettsial gene sequences of P. japonica, rather than those of V. carteri strain UTEX 2180. Conclusion/Significance At least two different rickettsial organisms may have invaded the V. carteri lineage, one of which may be the direct ancestor of the endosymbiont of V. carteri strain UTEX 2180, whereas the other may be closely related to the endosymbiont of P. japonica. Endosymbiotic gene transfer from the latter rickettsial organism may have occurred in an ancestor of V. carteri. Thus, the rickettsiae may be widely associated with V. carteri, and likely have often been lost during host evolution.
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Rickettsial genes and gene-like sequences in the genomes of Volvox carteri and rickettsial possible endosymbionts.
2015Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Schematic representations of arrangements/synteny of several rickettsial genes and gene-like sequences present in DNA of the nuclear genome of V. carteri (A) and in the genomes of rickettsial possible endosymbionts harbored by three volvocalean species (B-D). Coding DNA sequences (CDSs) and CDS-like regions are shown as boxes. Rickettsial CDSs/CDS-like regions are shown in pale yellow, the V. carteri transposon Jordan-like region in green and others in black. Placement of boxes above/below the line indicates gene direction (from left-to-right or right-to-left, respectively). Black double-headed arrows on the baseline indicate the regions sequenced in the present study. Colored triangles under boxes indicate the locations of primers used for semi-quantitative genomic PCR (16S rRNA gene 5′-region: magenta, 16S rRNA gene 3′-region: light blue, murB: orange, ddlB: green; Fig. 2E). For accession numbers of sequences used in this figure, see S3 Table. (A) Part of scaffold 6 of the V. carteri f. nagariensis strain EVE nuclear genome. (B) Part of the Carteria cerasiformis NIES-425 draft endosymbiont genome, including 16S rRNA (first line) and murB-ftsQ (second line). White triangles indicate primers used to amplify the sequencing templates (ccmF-R02 and phbB-F01; see Materials and Methods). (C) Part of the genome of a possible endosymbiont of V. carteri f. weismannia strain UTEX 2180, including murB and ddlB (right). The 16S rRNA gene of the endosymbiont [12] is also shown (left). (D) Part of the genome of a possible endosymbiont of Pleodorina japonica strain NIES-577, including murB and ddlB (right). The 16S rRNA gene [11] is also shown (left).
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a rickettsial endosymbiont inhabiting the cytoplasm of volvox carteri volvocales chlorophyceae
Phycologia, 2014Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Hisayoshi NozakiAbstract:A bacterial endosymbiont was previously observed in the green alga Volvox carteri strain UTEX 2180 using transmission electron microscopy, although its phylogenetic status was unknown. Here, we identified the bacterial endosymbiont based on analyses of the 16S ribosomal RNA (rRNA) gene. The endosymbiont of V. carteri belongs to the “hydra group” characterized by non-arthropod hosts, within the eubacterial family Rickettsiaceae (Rickettsiales; Alphaproteobacteria). In the hydra group, the endosymbiont formed a clade with the endosymbionts of the volvocaleans Carteria cerasiformis and Pleodorina japonica and the ciliate Diophrys appendiculata but was separated from the endosymbionts of marine green macroalgae (Bryopsis spp.). Fluorescence in situ hybridization using a probe specific for the 16S rRNA of the V. carteri endosymbiont confirmed our molecular identification and the distribution of the endosymbiont within the host cytoplasm. Rickettsial endosymbionts were not detected in eight other strains of V. ...
Takashi Hamaji - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Two Different Rickettsial Bacteria Invading
2016Co-Authors: Volvox Carteri, Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Background Bacteria of the family Rickettsiaceae are principally associated with arthropods. Recently, endosymbionts of the Rickettsiaceae have been found in non-phagotrophic cells of the vol-vocalean green algae Carteria cerasiformis, Pleodorina japonica, and Volvox carteri. Such endosymbionts were present in only C. cerasiformis strain NIES-425 and V. carteri strain UTEX 2180, of various strains of Carteria and V. carteri examined, suggesting that rickettsial endosymbionts may have been transmitted to only a few algal strains very recently. Howev-er, in preliminary work, we detected a sequence similar to that of a rickettsial gene in the nu-clear genome of V. carteri strain EVE. Methodology/Principal Findings Here we explored the origin of the rickettsial gene-like sequences in the endosymbiont-lack-ing V. carteri strain EVE, by performing comparative analyses on 13 strains of V. carteri. By reference to our ongoing genomic sequence of rickettsial endosymbionts in C. cerasiformis strain NIES-425 cells, we confirmed that an approximately 9-kbp DNA sequence encom-passing a region similar to that of four rickettsial genes was present in the nuclear genome of V. carteri strain EVE. Phylogenetic analyses, and comparisons of the synteny of rickettsi-al gene-like sequences from various strains of V. carteri, indicated that the rickettsial gene-like sequences in the nuclear genome of V. carteri strain EVE were closely related to rickett-sial gene sequences of P. japonica, rather than those of V. carteri strain UTEX 2180
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two different rickettsial bacteria invading volvox carteri
PLOS ONE, 2015Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Background Bacteria of the family Rickettsiaceae are principally associated with arthropods. Recently, endosymbionts of the Rickettsiaceae have been found in non-phagotrophic cells of the volvocalean green algae Carteria cerasiformis, Pleodorina japonica, and Volvox carteri. Such endosymbionts were present in only C. cerasiformis strain NIES-425 and V. carteri strain UTEX 2180, of various strains of Carteria and V. carteri examined, suggesting that rickettsial endosymbionts may have been transmitted to only a few algal strains very recently. However, in preliminary work, we detected a sequence similar to that of a rickettsial gene in the nuclear genome of V. carteri strain EVE. Methodology/Principal Findings Here we explored the origin of the rickettsial gene-like sequences in the endosymbiont-lacking V. carteri strain EVE, by performing comparative analyses on 13 strains of V. carteri. By reference to our ongoing genomic sequence of rickettsial endosymbionts in C. cerasiformis strain NIES-425 cells, we confirmed that an approximately 9-kbp DNA sequence encompassing a region similar to that of four rickettsial genes was present in the nuclear genome of V. carteri strain EVE. Phylogenetic analyses, and comparisons of the synteny of rickettsial gene-like sequences from various strains of V. carteri, indicated that the rickettsial gene-like sequences in the nuclear genome of V. carteri strain EVE were closely related to rickettsial gene sequences of P. japonica, rather than those of V. carteri strain UTEX 2180. Conclusion/Significance At least two different rickettsial organisms may have invaded the V. carteri lineage, one of which may be the direct ancestor of the endosymbiont of V. carteri strain UTEX 2180, whereas the other may be closely related to the endosymbiont of P. japonica. Endosymbiotic gene transfer from the latter rickettsial organism may have occurred in an ancestor of V. carteri. Thus, the rickettsiae may be widely associated with V. carteri, and likely have often been lost during host evolution.
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Rickettsial genes and gene-like sequences in the genomes of Volvox carteri and rickettsial possible endosymbionts.
2015Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Schematic representations of arrangements/synteny of several rickettsial genes and gene-like sequences present in DNA of the nuclear genome of V. carteri (A) and in the genomes of rickettsial possible endosymbionts harbored by three volvocalean species (B-D). Coding DNA sequences (CDSs) and CDS-like regions are shown as boxes. Rickettsial CDSs/CDS-like regions are shown in pale yellow, the V. carteri transposon Jordan-like region in green and others in black. Placement of boxes above/below the line indicates gene direction (from left-to-right or right-to-left, respectively). Black double-headed arrows on the baseline indicate the regions sequenced in the present study. Colored triangles under boxes indicate the locations of primers used for semi-quantitative genomic PCR (16S rRNA gene 5′-region: magenta, 16S rRNA gene 3′-region: light blue, murB: orange, ddlB: green; Fig. 2E). For accession numbers of sequences used in this figure, see S3 Table. (A) Part of scaffold 6 of the V. carteri f. nagariensis strain EVE nuclear genome. (B) Part of the Carteria cerasiformis NIES-425 draft endosymbiont genome, including 16S rRNA (first line) and murB-ftsQ (second line). White triangles indicate primers used to amplify the sequencing templates (ccmF-R02 and phbB-F01; see Materials and Methods). (C) Part of the genome of a possible endosymbiont of V. carteri f. weismannia strain UTEX 2180, including murB and ddlB (right). The 16S rRNA gene of the endosymbiont [12] is also shown (left). (D) Part of the genome of a possible endosymbiont of Pleodorina japonica strain NIES-577, including murB and ddlB (right). The 16S rRNA gene [11] is also shown (left).