1
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Takahashi K, Kuwahara H, Horikawa Y, Izawa K, Kato D, Inagaki T, Yuki M, Ohkuma M, Hongoh Y. Emergence of putative energy parasites within Clostridia revealed by genome analysis of a novel endosymbiotic clade. ISME J 2023; 17:1895-1906. [PMID: 37653056 PMCID: PMC10579323 DOI: 10.1038/s41396-023-01502-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 08/21/2023] [Accepted: 08/23/2023] [Indexed: 09/02/2023]
Abstract
The Clostridia is a dominant bacterial class in the guts of various animals and are considered to nutritionally contribute to the animal host. Here, we discovered clostridial endosymbionts of cellulolytic protists in termite guts, which have never been reported with evidence. We obtained (near-)complete genome sequences of three endosymbiotic Clostridia, each associated with a different parabasalid protist species with various infection rates: Trichonympha agilis, Pseudotrichonympha grassii, and Devescovina sp. All these protists are previously known to harbor permanently-associated, mutualistic Endomicrobia or Bacteroidales that supplement nitrogenous compounds. The genomes of the endosymbiotic Clostridia were small in size (1.0-1.3 Mbp) and exhibited signatures of an obligately-intracellular parasite, such as an extremely limited capability to synthesize amino acids, cofactors, and nucleotides and a disrupted glycolytic pathway with no known net ATP-generating system. Instead, the genomes encoded ATP/ADP translocase and, interestingly, regulatory proteins that are unique to eukaryotes in general and are possibly used to interfere with host cellular processes. These three genomes formed a clade with metagenome-assembled genomes (MAGs) derived from the guts of other animals, including human and ruminants, and the MAGs shared the characteristics of parasites. Gene flux analysis suggested that the acquisition of the ATP/ADP translocase gene in a common ancestor was probably key to the emergence of this parasitic clade. Taken together, we provide novel insights into the multilayered symbiotic system in the termite gut by adding the presence of parasitism and present an example of the emergence of putative energy parasites from a dominant gut bacterial clade.
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Affiliation(s)
- Kazuki Takahashi
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan.
| | - Hirokazu Kuwahara
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Yutaro Horikawa
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Kazuki Izawa
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Daiki Kato
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Tatsuya Inagaki
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Masahiro Yuki
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, 305-0074, Japan
| | - Moriya Ohkuma
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, 305-0074, Japan
| | - Yuichi Hongoh
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan.
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, 305-0074, Japan.
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2
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Takeuchi M, Kuwahara H, Murakami T, Takahashi K, Kajitani R, Toyoda A, Itoh T, Ohkuma M, Hongoh Y. Parallel reductive genome evolution in Desulfovibrio ectosymbionts independently acquired by Trichonympha protists in the termite gut. ISME J 2020; 14:2288-2301. [PMID: 32483307 PMCID: PMC7608387 DOI: 10.1038/s41396-020-0688-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/13/2020] [Accepted: 05/21/2020] [Indexed: 12/13/2022]
Abstract
Several Trichonympha protist species in the termite gut have independently acquired Desulfovibrio ectosymbionts in apparently different stages of symbiosis. Here, we obtained the near-complete genome sequence of Desulfovibrio phylotype ZnDsv-02, which attaches to the surface of Trichonympha collaris cells, and compared it with a previously obtained genome sequence of 'Candidatus Desulfovibrio trichonymphae' phylotype Rs-N31, which is almost completely embedded in the cytoplasm of Trichonympha agilis. Single-nucleotide polymorphism analysis indicated that although Rs-N31 is almost clonal, the ZnDsv-02 population on a single host cell is heterogeneous. Despite these differences, the genome of ZnDsv-02 has been reduced to 1.6 Mb, which is comparable to that of Rs-N31 (1.4 Mb), but unlike other known ectosymbionts of protists with a genome similar in size to their free-living relatives. Except for the presence of a lactate utilization pathway, cell-adhesion components and anti-phage defense systems in ZnDsv-02, the overall gene-loss pattern between the two genomes is very similar, including the loss of genes responsive to environmental changes. Our study suggests that genome reduction can occur in ectosymbionts, even when they can be transmitted horizontally and obtain genes via lateral transfer, and that the symbiont genome size depends heavily on their role in the symbiotic system.
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Affiliation(s)
- Mariko Takeuchi
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Hirokazu Kuwahara
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan.
| | - Takumi Murakami
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
- Department of Informatics, National Institute of Genetics, Shizuoka, 411-8540, Japan
- Advanced Genomics Center, National Institute of Genetics, Shizuoka, 411-8540, Japan
| | - Kazuki Takahashi
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Rei Kajitani
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Atsushi Toyoda
- Advanced Genomics Center, National Institute of Genetics, Shizuoka, 411-8540, Japan
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Shizuoka, 411-8540, Japan
| | - Takehiko Itoh
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Moriya Ohkuma
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, 305-0074, Japan
| | - Yuichi Hongoh
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan.
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, 305-0074, Japan.
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3
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Utami YD, Kuwahara H, Igai K, Murakami T, Sugaya K, Morikawa T, Nagura Y, Yuki M, Deevong P, Inoue T, Kihara K, Lo N, Yamada A, Ohkuma M, Hongoh Y. Genome analyses of uncultured TG2/ZB3 bacteria in 'Margulisbacteria' specifically attached to ectosymbiotic spirochetes of protists in the termite gut. ISME J 2019; 13:455-467. [PMID: 30287885 PMCID: PMC6331581 DOI: 10.1038/s41396-018-0297-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 09/20/2018] [Accepted: 09/25/2018] [Indexed: 11/09/2022]
Abstract
We investigated the phylogenetic diversity, localisation and metabolism of an uncultured bacterial clade, Termite Group 2 (TG2), or ZB3, in the termite gut, which belongs to the candidate phylum 'Margulisbacteria'. We performed 16S rRNA amplicon sequencing analysis and detected TG2/ZB3 sequences in 40 out of 72 termite and cockroach species, which exclusively constituted a monophyletic cluster in the TG2/ZB3 clade. Fluorescence in situ hybridisation analysis in lower termites revealed that these bacteria are specifically attached to ectosymbiotic spirochetes of oxymonad gut protists. Draft genomes of four TG2/ZB3 phylotypes from a small number of bacterial cells were reconstructed, and functional genome analysis suggested that these bacteria hydrolyse and ferment cellulose/cellobiose to H2, CO2, acetate and ethanol. We also assembled a draft genome for a partner Treponema spirochete and found that it encoded genes for reductive acetogenesis from H2 and CO2. We hypothesise that the TG2/ZB3 bacteria we report here are commensal or mutualistic symbionts of the spirochetes, exploiting the spirochetes as H2 sinks. For these bacteria, we propose a novel genus, 'Candidatus Termititenax', which represents a hitherto uncharacterised class-level clade in 'Margulisbacteria'. Our findings add another layer, i.e., cellular association between bacteria, to the multi-layered symbiotic system in the termite gut.
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Affiliation(s)
- Yuniar Devi Utami
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Hirokazu Kuwahara
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Katsura Igai
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Takumi Murakami
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Kaito Sugaya
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Takahiro Morikawa
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Yuichi Nagura
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Masahiro Yuki
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, 305-0074, Japan
| | - Pinsurang Deevong
- Department of Microbiology, Kasetsart University, Bangkok, 10900, Thailand
| | - Tetsushi Inoue
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, 852-8521, Japan
| | - Kumiko Kihara
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Nathan Lo
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Akinori Yamada
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, 852-8521, Japan
| | - Moriya Ohkuma
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, 305-0074, Japan
| | - Yuichi Hongoh
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan.
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, 305-0074, Japan.
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4
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Kinjo Y, Bourguignon T, Tong KJ, Kuwahara H, Lim SJ, Yoon KB, Shigenobu S, Park YC, Nalepa CA, Hongoh Y, Ohkuma M, Lo N, Tokuda G. Parallel and Gradual Genome Erosion in the Blattabacterium Endosymbionts of Mastotermes darwiniensis and Cryptocercus Wood Roaches. Genome Biol Evol 2018; 10:1622-1630. [PMID: 29860278 PMCID: PMC6022663 DOI: 10.1093/gbe/evy110] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2018] [Indexed: 12/23/2022] Open
Abstract
Almost all examined cockroaches harbor an obligate intracellular endosymbiont, Blattabacterium cuenoti. On the basis of genome content, Blattabacterium has been inferred to recycle nitrogen wastes and provide amino acids and cofactors for its hosts. Most Blattabacterium strains sequenced to date harbor a genome of ∼630 kbp, with the exception of the termite Mastotermes darwiniensis (∼590 kbp) and Cryptocercus punctulatus (∼614 kbp), a representative of the sister group of termites. Such genome reduction may have led to the ultimate loss of Blattabacterium in all termites other than Mastotermes. In this study, we sequenced 11 new Blattabacterium genomes from three species of Cryptocercus in order to shed light on the genomic evolution of Blattabacterium in termites and Cryptocercus. All genomes of Cryptocercus-derived Blattabacterium genomes were reduced (∼614 kbp), except for that associated with Cryptocercus kyebangensis, which comprised 637 kbp. Phylogenetic analysis of these genomes and their content indicates that Blattabacterium experienced parallel genome reduction in Mastotermes and Cryptocercus, possibly due to similar selective forces. We found evidence of ongoing genome reduction in Blattabacterium from three lineages of the C. punctulatus species complex, which independently lost one cysteine biosynthetic gene. We also sequenced the genome of the Blattabacterium associated with Salganea taiwanensis, a subsocial xylophagous cockroach that does not vertically transmit gut symbionts via proctodeal trophallaxis. This genome was 632 kbp, typical of that of nonsubsocial cockroaches. Overall, our results show that genome reduction occurred on multiple occasions in Blattabacterium, and is still ongoing, possibly because of new associations with gut symbionts in some lineages.
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Affiliation(s)
- Yukihiro Kinjo
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Japan.,Department of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan.,Okinawa Institute of Science and Technology, Graduate University, Okinawa, Japan.,Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan
| | - Thomas Bourguignon
- Okinawa Institute of Science and Technology, Graduate University, Okinawa, Japan.,Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, Czech Republic
| | - Kwei Jun Tong
- School of Life and Environmental Sciences, University of Sydney, NSW, Australia
| | - Hirokazu Kuwahara
- Department of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Sang Jin Lim
- Division of Forest Science, Kangwon National University, Chuncheon, Republic of Korea
| | - Kwang Bae Yoon
- Division of Forest Science, Kangwon National University, Chuncheon, Republic of Korea
| | - Shuji Shigenobu
- National Institute for Basic Biology, NIBB Core Research Facilities, Okazaki, Japan
| | - Yung Chul Park
- Division of Forest Science, Kangwon National University, Chuncheon, Republic of Korea
| | - Christine A Nalepa
- Department of Entomology, North Carolina State University, Raleigh, North Carolina, USA
| | - Yuichi Hongoh
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Japan.,Department of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Moriya Ohkuma
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Japan
| | - Nathan Lo
- School of Life and Environmental Sciences, University of Sydney, NSW, Australia
| | - Gaku Tokuda
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan
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5
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Utami YD, Kuwahara H, Murakami T, Morikawa T, Sugaya K, Kihara K, Yuki M, Lo N, Deevong P, Hasin S, Boonriam W, Inoue T, Yamada A, Ohkuma M, Hongoh Y. Phylogenetic Diversity and Single-Cell Genome Analysis of "Melainabacteria", a Non-Photosynthetic Cyanobacterial Group, in the Termite Gut. Microbes Environ 2018; 33:50-57. [PMID: 29415909 PMCID: PMC5877343 DOI: 10.1264/jsme2.me17137] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Termite guts harbor diverse yet-uncultured bacteria, including a non-photosynthetic cyanobacterial group, the class "Melainabacteria". We herein reported the phylogenetic diversity of "Melainabacteria" in the guts of diverse termites and conducted a single-cell genome analysis of a melainabacterium obtained from the gut of the termite Termes propinquus. We performed amplicon sequencing of 16S rRNA genes from the guts of 60 termite and eight cockroach species, and detected melainabacterial sequences in 48 out of the 68 insect species, albeit with low abundances (0.02-1.90%). Most of the melainabacterial sequences obtained were assigned to the order "Gastranaerophilales" and appeared to form clusters unique to termites and cockroaches. A single-cell genome of a melainabacterium, designated phylotype Tpq-Mel-01, was obtained using a fluorescence-activated cell sorter and whole genome amplification. The genome shared basic features with other melainabacterial genomes previously reconstructed from the metagenomes of human and koala feces. The bacterium had a small genome (~1.6 Mb) and possessed fermentative pathways possibly using sugars and chitobiose as carbon and energy sources, while the pathways for photosynthesis and carbon fixation were not found. The genome contained genes for flagellar components and chemotaxis; therefore, the bacterium is likely motile. A fluorescence in situ hybridization analysis showed that the cells of Tpq-Mel-01 and/or its close relatives are short rods with the dimensions of 1.1±0.2 μm by 0.5±0.1 μm; for these bacteria, we propose the novel species, "Candidatus Gastranaerophilus termiticola". Our results provide fundamental information on "Melainabacteria" in the termite gut and expand our knowledge on this underrepresented, non-photosynthetic cyanobacterial group.
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Affiliation(s)
| | | | - Takumi Murakami
- Department of Biological Sciences, Tokyo Institute of Technology
| | | | - Kaito Sugaya
- Department of Biological Sciences, Tokyo Institute of Technology
| | - Kumiko Kihara
- Department of Biological Sciences, Tokyo Institute of Technology
| | - Masahiro Yuki
- Biomass Research Platform Team, RIKEN Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource Science
| | - Nathan Lo
- School of Biological Sciences, University of Sydney
| | | | - Sasitorn Hasin
- College of Innovative Management, Valaya Alongkorn Rajabhat University under the Royal Patronage
| | | | - Tetsushi Inoue
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University
| | - Akinori Yamada
- Department of Biological Sciences, Tokyo Institute of Technology.,Graduate School of Fisheries and Environmental Sciences, Nagasaki University
| | - Moriya Ohkuma
- Biomass Research Platform Team, RIKEN Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource Science.,Japan Collection of Microorganisms, RIKEN BioResource Center
| | - Yuichi Hongoh
- Department of Biological Sciences, Tokyo Institute of Technology.,Japan Collection of Microorganisms, RIKEN BioResource Center
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6
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Anraku Y, Kuwahara H, Fukusato Y, Mizoguchi A, Ishii T, Nitta K, Matsumoto Y, Toh K, Miyata K, Uchida S, Nishina K, Osada K, Itaka K, Nishiyama N, Mizusawa H, Yamasoba T, Yokota T, Kataoka K. Glycaemic control boosts glucosylated nanocarrier crossing the BBB into the brain. Nat Commun 2017; 8:1001. [PMID: 29042554 PMCID: PMC5645389 DOI: 10.1038/s41467-017-00952-3] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 08/07/2017] [Indexed: 01/11/2023] Open
Abstract
Recently, nanocarriers that transport bioactive substances to a target site in the body have attracted considerable attention and undergone rapid progression in terms of the state of the art. However, few nanocarriers can enter the brain via a systemic route through the blood-brain barrier (BBB) to efficiently reach neurons. Here we prepare a self-assembled supramolecular nanocarrier with a surface featuring properly configured glucose. The BBB crossing and brain accumulation of this nanocarrier are boosted by the rapid glycaemic increase after fasting and by the putative phenomenon of the highly expressed glucose transporter-1 (GLUT1) in brain capillary endothelial cells migrating from the luminal to the abluminal plasma membrane. The precisely controlled glucose density on the surface of the nanocarrier enables the regulation of its distribution within the brain, and thus is successfully optimized to increase the number of nanocarriers accumulating in neurons.There are only a few examples of nanocarriers that can transport bioactive substances across the blood-brain barrier. Here the authors show that by rapid glycaemic increase the accumulation of a glucosylated nanocarrier in the brain can be controlled.
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Affiliation(s)
- Y Anraku
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - H Kuwahara
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - Y Fukusato
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - A Mizoguchi
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - T Ishii
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - K Nitta
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - Y Matsumoto
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.,Department of Otorhinolaryngology and Head and Neck Surgery, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - K Toh
- Innovation Center of NanoMedicine, Kawasaki Institute of Industrial Promotion, 3-25-14 Tonomachi, Kawasaki-ku, Kawasaki, 210-0821, Japan
| | - K Miyata
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.,Department of Materials Engineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - S Uchida
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.,Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - K Nishina
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - K Osada
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - K Itaka
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - N Nishiyama
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, R1-11, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
| | - H Mizusawa
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - T Yamasoba
- Department of Otorhinolaryngology and Head and Neck Surgery, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - T Yokota
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan. .,Center for Brain Integration Research, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
| | - K Kataoka
- Innovation Center of NanoMedicine, Kawasaki Institute of Industrial Promotion, 3-25-14 Tonomachi, Kawasaki-ku, Kawasaki, 210-0821, Japan. .,Policy Alternatives Research Institute, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
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7
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Yoshioka K, Kunieda T, Asami Y, Sujino Y, Tanaka K, Piao W, Kuwahara H, Nishina K, Nagata T, Yokota T. Dual overhanging-duplex oligonucleotide improved efficacy and safety in gene therapy for FAP. J Neurol Sci 2017. [DOI: 10.1016/j.jns.2017.08.416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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8
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Kuwahara H, Song J, Shimoura T, Yoshida-Tanaka K, Mizuno T, Mochizuki T, Nishina K, Nagata T, Kusuhara H, Yokota T. Heteroduplex oligonucleotide as a platform technology to modulate blood-brain barrier function in vivo. J Neurol Sci 2017. [DOI: 10.1016/j.jns.2017.08.417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Li F, Ishibashi S, Iwasawa E, Song J, Ichijo M, Zhang Y, Piao W, Yoshida K, Yoshioka K, Kuwahara H, Nagata T, Yokota T. Gene silencing effect of heteroduplex oligonucleotide and its biodistribution in neurons and brain endothelial cells after ischemia. J Neurol Sci 2017. [DOI: 10.1016/j.jns.2017.08.2483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Nagata T, Ohyagi M, Ihara K, Kaburagi H, Nishina K, Piao W, Yoshida-Tanaka K, Kuwahara H, Yoshioka K, Yokota T. The effect of DNA/RNA heteroduplex oligonucleotides on muscle. J Neurol Sci 2017. [DOI: 10.1016/j.jns.2017.08.2383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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11
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Izawa K, Kuwahara H, Sugaya K, Lo N, Ohkuma M, Hongoh Y. Discovery of ectosymbiotic Endomicrobium lineages associated with protists in the gut of stolotermitid termites. Environ Microbiol Rep 2017; 9:411-418. [PMID: 28556617 DOI: 10.1111/1758-2229.12549] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/19/2017] [Accepted: 05/18/2017] [Indexed: 06/07/2023]
Abstract
The genus Endomicrobium is a dominant bacterial group in the gut of lower termites, and most phylotypes are intracellular symbionts of gut protists. Here we report the discovery of Endomicrobium ectosymbionts of termite gut protists. We found that bristle-like Endomicrobium cells attached to the surface of spirotrichosomid protist cells inhabiting the termite Stolotermes victoriensis. Transmission electron microscopy revealed that a putative Endomicrobium cell likely attached to the protist surface via a protrusion from the tip of the bacterium. A phylotype, sharing 98.9% 16S rRNA sequence identity with the Endomicrobium ectosymbionts of the spirotrichosomid protists, was also found on the cell surface of the protist Trichonympha magna in the gut of the termite Porotermes adamsoni. We propose the novel species 'Candidatus Endomicrobium superficiale' for these bacteria. T. magna simultaneously harboured another Endomicrobium ectosymbiont that shared 93.5-94.2% 16S rRNA sequence identities with 'Ca. Endomicrobium superficiale'. Furthermore, Spirotrichonympha-like protists in P. adamsoni guts were associated with an Endomicrobium phylotype that possibly attached to the host flagella. A phylogenetic analysis suggested that these ectosymbiotic lineages have evolved multiple times from free-living Endomicrobium lineages and are relatively distant from the endosymbionts. Our results provide novel insights into the ecology and evolution of the Endomicrobium.
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Affiliation(s)
- Kazuki Izawa
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Hirokazu Kuwahara
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Kaito Sugaya
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Nathan Lo
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia
| | - Moriya Ohkuma
- RIKEN BioResource Center, Japan Collection of Microorganisms, Tsukuba, 305-0074, Japan
| | - Yuichi Hongoh
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
- RIKEN BioResource Center, Japan Collection of Microorganisms, Tsukuba, 305-0074, Japan
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12
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Pramono AK, Kuwahara H, Itoh T, Toyoda A, Yamada A, Hongoh Y. Discovery and Complete Genome Sequence of a Bacteriophage from an Obligate Intracellular Symbiont of a Cellulolytic Protist in the Termite Gut. Microbes Environ 2017; 32:112-117. [PMID: 28321010 PMCID: PMC5478533 DOI: 10.1264/jsme2.me16175] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Termites depend nutritionally on their gut microbes, and protistan, bacterial, and archaeal gut communities have been extensively studied. However, limited information is available on viruses in the termite gut. We herein report the complete genome sequence (99,517 bp) of a phage obtained during a genome analysis of “Candidatus Azobacteroides pseudotrichonymphae” phylotype ProJPt-1, which is an obligate intracellular symbiont of the cellulolytic protist Pseudotrichonympha sp. in the gut of the termite Prorhinotermes japonicus. The genome of the phage, designated ProJPt-Bp1, was circular or circularly permuted, and was not integrated into the two circular chromosomes or five circular plasmids composing the host ProJPt-1 genome. The phage was putatively affiliated with the order Caudovirales based on sequence similarities with several phage-related genes; however, most of the 52 protein-coding sequences had no significant homology to sequences in the databases. The phage genome contained a tRNA-Gln (CAG) gene, which showed the highest sequence similarity to the tRNA-Gln (CAA) gene of the host “Ca. A. pseudotrichonymphae” phylotype ProJPt-1. Since the host genome lacked a tRNA-Gln (CAG) gene, the phage tRNA gene may compensate for differences in codon usage bias between the phage and host genomes. The phage genome also contained a non-coding region with high nucleotide sequence similarity to a region in one of the host plasmids. No other phage-related sequences were found in the host ProJPt-1 genome. To the best of our knowledge, this is the first report of a phage from an obligate, mutualistic endosymbiont permanently associated with eukaryotic cells.
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Affiliation(s)
- Ajeng K Pramono
- Department of Biological Sciences, Tokyo Institute of Technology
| | | | - Takehiko Itoh
- Department of Biological Information, Tokyo Institute of Technology
| | | | - Akinori Yamada
- Department of Biological Sciences, Tokyo Institute of Technology.,Division of Marine Biomaterial Science, Graduate School of Fisheries Science and Environmental Studies, Nagasaki University
| | - Yuichi Hongoh
- Department of Biological Sciences, Tokyo Institute of Technology
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13
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Kuwahara H, Yuki M, Izawa K, Ohkuma M, Hongoh Y. Genome of 'Ca. Desulfovibrio trichonymphae', an H 2-oxidizing bacterium in a tripartite symbiotic system within a protist cell in the termite gut. ISME J 2016; 11:766-776. [PMID: 27801909 PMCID: PMC5322295 DOI: 10.1038/ismej.2016.143] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 08/19/2016] [Accepted: 09/02/2016] [Indexed: 11/23/2022]
Abstract
The cellulolytic protist Trichonympha agilis in the termite gut permanently hosts two symbiotic bacteria, ‘Candidatus Endomicrobium trichonymphae' and ‘Candidatus Desulfovibrio trichonymphae'. The former is an intracellular symbiont, and the latter is almost intracellular but still connected to the outside via a small pore. The complete genome of ‘Ca. Endomicrobium trichonymphae' has previously been reported, and we here present the complete genome of ‘Ca. Desulfovibrio trichonymphae'. The genome is small (1 410 056 bp), has many pseudogenes, and retains biosynthetic pathways for various amino acids and cofactors, which are partially complementary to those of ‘Ca. Endomicrobium trichonymphae'. An amino acid permease gene has apparently been transferred between the ancestors of these two symbionts; a lateral gene transfer has affected their metabolic capacity. Notably, ‘Ca. Desulfovibrio trichonymphae' retains the complex system to oxidize hydrogen by sulfate and/or fumarate, while genes for utilizing other substrates common in desulfovibrios are pseudogenized or missing. Thus, ‘Ca. Desulfovibrio trichonymphae' is specialized to consume hydrogen that may otherwise inhibit fermentation processes in both T. agilis and ‘Ca. Endomicrobium trichonymphae'. The small pore may be necessary to take up sulfate. This study depicts a genome-based model of a multipartite symbiotic system within a cellulolytic protist cell in the termite gut.
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Affiliation(s)
- Hirokazu Kuwahara
- Department of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Masahiro Yuki
- Biomass Research Platform Team, RIKEN Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource Science, Tsukuba, Japan
| | - Kazuki Izawa
- Department of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Moriya Ohkuma
- Biomass Research Platform Team, RIKEN Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource Science, Tsukuba, Japan.,Japan Collection of Microorganisms, RIKEN BioResource Center, Tsukuba, Japan
| | - Yuichi Hongoh
- Department of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan.,Japan Collection of Microorganisms, RIKEN BioResource Center, Tsukuba, Japan
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14
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Izawa K, Kuwahara H, Kihara K, Yuki M, Lo N, Itoh T, Ohkuma M, Hongoh Y. Comparison of Intracellular "Ca. Endomicrobium Trichonymphae" Genomovars Illuminates the Requirement and Decay of Defense Systems against Foreign DNA. Genome Biol Evol 2016; 8:3099-3107. [PMID: 27635050 PMCID: PMC5174739 DOI: 10.1093/gbe/evw227] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
“Candidatus Endomicrobium trichonymphae” (Bacteria; Elusimicrobia) is an obligate intracellular symbiont of the cellulolytic protist genus Trichonympha in the termite gut. A previous genome analysis of “Ca. Endomicrobium trichonymphae” phylotype Rs-D17 (genomovar Ri2008), obtained from a Trichonympha agilis cell in the gut of the termite Reticulitermes speratus, revealed that its genome is small (1.1 Mb) and contains many pseudogenes; it is in the course of reductive genome evolution. Here we report the complete genome sequence of another Rs-D17 genomovar, Ti2015, obtained from a different T. agilis cell present in an R. speratus gut. These two genomovars share most intact protein-coding genes and pseudogenes, showing 98.6% chromosome sequence similarity. However, characteristic differences were found in their defense systems, which comprised restriction-modification and CRISPR/Cas systems. The repertoire of intact restriction-modification systems differed between the genomovars, and two of the three CRISPR/Cas loci in genomovar Ri2008 are pseudogenized or missing in genomovar Ti2015. These results suggest relaxed selection pressure for maintaining these defense systems. Nevertheless, the remaining CRISPR/Cas system in each genomovar appears to be active; none of the “spacer” sequences (112 in Ri2008 and 128 in Ti2015) were shared whereas the “repeat” sequences were identical. Furthermore, we obtained draft genomes of three additional endosymbiotic Endomicrobium phylotypes from different host protist species, and discovered multiple, intact CRISPR/Cas systems in each genome. Collectively, unlike bacteriome endosymbionts in insects, the Endomicrobium endosymbionts of termite-gut protists appear to require defense against foreign DNA, although the required level of defense has likely been reduced during their intracellular lives.
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Affiliation(s)
- Kazuki Izawa
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, Japan
| | - Hirokazu Kuwahara
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, Japan
| | - Kumiko Kihara
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, Japan Department of Biological and Chemical Systems Engineering, National Institute of Technology Kumamoto College, Yatsushiro, Japan
| | - Masahiro Yuki
- Biomass Research Platform Team, RIKEN Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource Science, Tsukuba, Japan
| | - Nathan Lo
- School of Biological Sciences, University of Sydney, Sydney, NSW, Australia
| | - Takehiko Itoh
- Department of Biological Information, Tokyo Institute of Technology, Tokyo, Japan
| | - Moriya Ohkuma
- Biomass Research Platform Team, RIKEN Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource Science, Tsukuba, Japan Japan Collection of Microorganisms, RIKEN BioResource Center, Tsukuba, Japan
| | - Yuichi Hongoh
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo, Japan Japan Collection of Microorganisms, RIKEN BioResource Center, Tsukuba, Japan
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15
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Koborinai R, Dissanayake SE, Reehuis M, Matsuda M, Kajita T, Kuwahara H, Lee SH, Katsufuji T. Orbital Glass State of the Nearly Metallic Spinel Cobalt Vanadate. Phys Rev Lett 2016; 116:037201. [PMID: 26849610 DOI: 10.1103/physrevlett.116.037201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Indexed: 06/05/2023]
Abstract
Strain, magnetization, dielectric relaxation, and unpolarized and polarized neutron diffraction measurements were performed to study the magnetic and structural properties of spinel Co_{1-x}V_{2+x}O_{4}. The strain measurement indicates that, upon cooling, ΔL/L in the order of ∼10^{-4} starts increasing below T_{C}, becomes maximum at T_{max}, and then decreases and changes its sign at T^{*}. Neutron measurements indicate that a collinear ferrimagnetic order develops below T_{C} and upon further cooling noncollinear ferrimagnetic ordering occurs below T_{max}. At low temperatures, the dielectric constant exhibits a frequency dependence, indicating slow dynamics. These results indicate the existence of an orbital glassy state at low temperatures in this nearly metallic frustrated magnet.
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Affiliation(s)
- R Koborinai
- Department of Physics, Waseda University, Tokyo 169-8555, Japan
| | - S E Dissanayake
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
| | - M Reehuis
- Helmholtz-Zentrum für Materialien und Energie, 14109 Berlin, Germany
| | - M Matsuda
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - T Kajita
- Department of Physics, Waseda University, Tokyo 169-8555, Japan
| | - H Kuwahara
- Department of Physics, Sophia University, Tokyo 102-8554, Japan
| | - S-H Lee
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
| | - T Katsufuji
- Department of Physics, Waseda University, Tokyo 169-8555, Japan
- Kagami Memorial Research Institute for Materials Science and Technology, Waseda University, Tokyo 169-0051, Japan
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16
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Mogi K, Shirataki C, Kihara K, Kuwahara H, Hongoh Y, Yamamoto T. Trapping and isolation of single prokaryotic cells in a micro-chamber array using dielectrophoresis. RSC Adv 2016. [DOI: 10.1039/c6ra21229h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The vast majority of prokaryotic species are difficult or impossible to culture in laboratories, which makes it difficult to study these organisms using conventional biochemical techniques.
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Affiliation(s)
- K. Mogi
- Department of Mechanical Engineering
- Tokyo Institute of Technology
- Tokyo 152-8552
- Japan
| | - C. Shirataki
- Department of Life Science and Technology
- Tokyo Institute of Technology
- Tokyo 152-8552
- Japan
| | - K. Kihara
- Department of Life Science and Technology
- Tokyo Institute of Technology
- Tokyo 152-8552
- Japan
| | - H. Kuwahara
- Department of Life Science and Technology
- Tokyo Institute of Technology
- Tokyo 152-8552
- Japan
| | - Y. Hongoh
- Department of Life Science and Technology
- Tokyo Institute of Technology
- Tokyo 152-8552
- Japan
| | - T. Yamamoto
- Department of Mechanical Engineering
- Tokyo Institute of Technology
- Tokyo 152-8552
- Japan
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17
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Yuki M, Kuwahara H, Shintani M, Izawa K, Sato T, Starns D, Hongoh Y, Ohkuma M. Dominant ectosymbiotic bacteria of cellulolytic protists in the termite gut also have the potential to digest lignocellulose. Environ Microbiol 2015; 17:4942-53. [DOI: 10.1111/1462-2920.12945] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 06/04/2015] [Accepted: 06/04/2015] [Indexed: 01/09/2023]
Affiliation(s)
- Masahiro Yuki
- Biomass Research Platform Team; RIKEN Biomass Engineering Program Cooperation Division; RIKEN Center for Sustainable Resource Science; Tsukuba Japan
| | - Hirokazu Kuwahara
- Department of Biological Sciences; Graduate School of Bioscience and Biotechnology; Tokyo Institute of Technology; Tokyo Japan
| | - Masaki Shintani
- Department of Engineering; Graduate School of Integrated Science and Technology; Shizuoka University; Hamamatsu Japan
- Japan Collection of Microorganisms; RIKEN BioResource Center; Tsukuba Japan
| | - Kazuki Izawa
- Department of Biological Sciences; Graduate School of Bioscience and Biotechnology; Tokyo Institute of Technology; Tokyo Japan
| | - Tomoyuki Sato
- Japan Collection of Microorganisms; RIKEN BioResource Center; Tsukuba Japan
| | - David Starns
- Japan Collection of Microorganisms; RIKEN BioResource Center; Tsukuba Japan
| | - Yuichi Hongoh
- Department of Biological Sciences; Graduate School of Bioscience and Biotechnology; Tokyo Institute of Technology; Tokyo Japan
- Japan Collection of Microorganisms; RIKEN BioResource Center; Tsukuba Japan
| | - Moriya Ohkuma
- Biomass Research Platform Team; RIKEN Biomass Engineering Program Cooperation Division; RIKEN Center for Sustainable Resource Science; Tsukuba Japan
- Japan Collection of Microorganisms; RIKEN BioResource Center; Tsukuba Japan
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18
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Tokunaga M, Akaki M, Ito T, Miyahara S, Miyake A, Kuwahara H, Furukawa N. Magnetic control of transverse electric polarization in BiFeO3. Nat Commun 2015; 6:5878. [DOI: 10.1038/ncomms6878] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 11/17/2014] [Indexed: 11/09/2022] Open
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Yamaguchi A, Tanaka S, Yamaguchi S, Kuwahara H, Takamura C, Imajoh-Ohmi S, Horikawa DD, Toyoda A, Katayama T, Arakawa K, Fujiyama A, Kubo T, Kunieda T. Two novel heat-soluble protein families abundantly expressed in an anhydrobiotic tardigrade. PLoS One 2012; 7:e44209. [PMID: 22937162 PMCID: PMC3429414 DOI: 10.1371/journal.pone.0044209] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 07/30/2012] [Indexed: 01/05/2023] Open
Abstract
Tardigrades are able to tolerate almost complete dehydration by reversibly switching to an ametabolic state. This ability is called anhydrobiosis. In the anhydrobiotic state, tardigrades can withstand various extreme environments including space, but their molecular basis remains largely unknown. Late embryogenesis abundant (LEA) proteins are heat-soluble proteins and can prevent protein-aggregation in dehydrated conditions in other anhydrobiotic organisms, but their relevance to tardigrade anhydrobiosis is not clarified. In this study, we focused on the heat-soluble property characteristic of LEA proteins and conducted heat-soluble proteomics using an anhydrobiotic tardigrade. Our heat-soluble proteomics identified five abundant heat-soluble proteins. All of them showed no sequence similarity with LEA proteins and formed two novel protein families with distinct subcellular localizations. We named them Cytoplasmic Abundant Heat Soluble (CAHS) and Secretory Abundant Heat Soluble (SAHS) protein families, according to their localization. Both protein families were conserved among tardigrades, but not found in other phyla. Although CAHS protein was intrinsically unstructured and SAHS protein was rich in β-structure in the hydrated condition, proteins in both families changed their conformation to an α-helical structure in water-deficient conditions as LEA proteins do. Two conserved repeats of 19-mer motifs in CAHS proteins were capable to form amphiphilic stripes in α-helices, suggesting their roles as molecular shield in water-deficient condition, though charge distribution pattern in α-helices were different between CAHS and LEA proteins. Tardigrades might have evolved novel protein families with a heat-soluble property and this study revealed a novel repertoire of major heat-soluble proteins in these anhydrobiotic animals.
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Affiliation(s)
- Ayami Yamaguchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Sae Tanaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Shiho Yamaguchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Hirokazu Kuwahara
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Chizuko Takamura
- Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | | | - Daiki D. Horikawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Atsushi Toyoda
- Center for Genetic Resource Information, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Toshiaki Katayama
- Human Genome Center, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Kazuharu Arakawa
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa, Japan
| | - Asao Fujiyama
- Center for Genetic Resource Information, National Institute of Genetics, Mishima, Shizuoka, Japan
- Principles of Informatics Research Division, National Institute of Informatics, Tokyo, Japan
| | - Takeo Kubo
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Takekazu Kunieda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- * E-mail:
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Horikawa DD, Yamaguchi A, Sakashita T, Tanaka D, Hamada N, Yukuhiro F, Kuwahara H, Kunieda T, Watanabe M, Nakahara Y, Wada S, Funayama T, Katagiri C, Higashi S, Yokobori SI, Kuwabara M, Rothschild LJ, Okuda T, Hashimoto H, Kobayashi Y. Tolerance of anhydrobiotic eggs of the Tardigrade Ramazzottius varieornatus to extreme environments. Astrobiology 2012; 12:283-289. [PMID: 22490117 DOI: 10.1089/ast.2011.0669] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Tardigrades are tiny (less than 1 mm in length) invertebrate animals that have the potential to survive travel to other planets because of their tolerance to extreme environmental conditions by means of a dry ametabolic state called anhydrobiosis. While the tolerance of adult tardigrades to extreme environments has been reported, there are few reports on the tolerance of their eggs. We examined the ability of hydrated and anhydrobiotic eggs of the tardigrade Ramazzottius varieornatus to hatch after exposure to ionizing irradiation (helium ions), extremely low and high temperatures, and high vacuum. We previously reported that there was a similar pattern of tolerance against ionizing radiation between hydrated and anhydrobiotic adults. In contrast, anhydrobiotic eggs (50% lethal dose; 1690 Gy) were substantially more radioresistant than hydrated ones (50% lethal dose; 509 Gy). Anhydrobiotic eggs also have a broader temperature resistance compared with hydrated ones. Over 70% of the anhydrobiotic eggs treated at either -196°C or +50°C hatched successfully, but all the hydrated eggs failed to hatch. After exposure to high-vacuum conditions (5.3×10(-4) Pa to 6.2×10(-5) Pa), the hatchability of the anhydrobiotic eggs was comparable to that of untreated control eggs.
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Kuwahara H, Takaki Y, Shimamura S, Yoshida T, Maeda T, Kunieda T, Maruyama T. Loss of genes for DNA recombination and repair in the reductive genome evolution of thioautotrophic symbionts of Calyptogena clams. BMC Evol Biol 2011; 11:285. [PMID: 21966992 PMCID: PMC3202245 DOI: 10.1186/1471-2148-11-285] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 10/03/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Two Calyptogena clam intracellular obligate symbionts, Ca. Vesicomyosocius okutanii (Vok; C. okutanii symbiont) and Ca. Ruthia magnifica (Rma; C. magnifica symbiont), have small genomes (1.02 and 1.16 Mb, respectively) with low G+C contents (31.6% and 34.0%, respectively) and are thought to be in an ongoing stage of reductive genome evolution (RGE). They lack recA and some genes for DNA repair, including mutY. The loss of recA and mutY is thought to contribute to the stabilization of their genome architectures and GC bias, respectively. To understand how these genes were lost from the symbiont genomes, we surveyed these genes in the genomes from 10 other Calyptogena clam symbionts using the polymerase chain reaction (PCR). RESULTS Phylogenetic trees reconstructed using concatenated 16S and 23S rRNA gene sequences showed that the symbionts formed two clades, clade I (symbionts of C. kawamurai, C. laubieri, C. kilmeri, C. okutanii and C. soyoae) and clade II (those of C. pacifica, C. fausta, C. nautilei, C. stearnsii, C. magnifica, C. fossajaponica and C. phaseoliformis). recA was detected by PCR with consensus primers for recA in the symbiont of C. phaseoliformis. A detailed homology search revealed a remnant recA in the Rma genome. Using PCR with a newly designed primer set, intact recA or its remnant was detected in clade II symbionts. In clade I symbionts, the recA coding region was found to be mostly deleted.In the Rma genome, a pseudogene of mutY was found. Using PCR with newly designed primer sets, mutY was not found in clade I symbionts but was found in clade II symbionts. The G+C content of 16S and 23S rRNA genes in symbionts lacking mutY was significantly lower than in those with mutY. CONCLUSIONS The extant Calyptogena clam symbionts in clade II were shown to have recA and mutY or their remnants, while those in clade I did not. The present results indicate that the extant symbionts are losing these genes in RGE, and that the loss of mutY contributed to the GC bias of the genomes during their evolution.
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Affiliation(s)
- Hirokazu Kuwahara
- Marine Biodiversity Research Program, Japan Agency for Marine-Earth Science and Technology, Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan
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Kuwahara H, Okuda T, Tomioka Y, Kimura T, Asamitsu A, Tokura Y. Phase Diagram and Anisotropic Transport Properties of Nd1-xSrxMnO3 Crystals. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-494-83] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTWe have investigated electronic transport and magnetic properties of perovskite-type Nd1-xSrxMnO3 crystals with change of controlled hole-doping level (0.30≤x≤0.80). The electronic phase diagram of Nd1-xSrxMnO3 was obtained by systematic measurements of magnetization (magnetic structure), resistivity, and lattice parameter. We have also studied the anisotropie transport properties of x=0.50 and 0.55 crystals with different magnetic structures: CE-type antiferromagnetic (AF) structure for x=0.50 and A-type layered AF one for x=0.55. In the case of the x=0.55 crystal, the metallic behavior was observed within the ferromagnetic (F) layers, while along the AF-coupling direction the crystal remains insulating over the whole temperature region. The observed large anisotropy is due to the magnetic as well as orbital-ordering induced confinement of the spin-polarized carriers within the F sheets. The nearly isotropie transport behavior has been confirmed for the CE-type AF charge-ordered state in the x=0.50 crystal.
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24
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Harada M, Yoshida T, Kuwahara H, Shimamura S, Takaki Y, Kato C, Miwa T, Miyake H, Maruyama T. Expression of genes for sulfur oxidation in the intracellular chemoautotrophic symbiont of the deep-sea bivalve Calyptogena okutanii. Extremophiles 2010; 13:895-903. [PMID: 19730970 DOI: 10.1007/s00792-009-0277-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Accepted: 08/19/2009] [Indexed: 11/30/2022]
Abstract
To understand sulfur oxidation in thioauto-trophic deep-sea clam symbionts, we analyzed the recently reported genomes of two chemoautotrophic symbionts of Calyptogena okutanii (Candidatus Vesicomyosocius okutanii strain HA: Vok) and C. magnifica (Candidatus Ruthia magnifica strain Cm: Rma), and examined the sulfur oxidation gene expressions in the Vok by RT-PCR. Both symbionts have genes for sulfide-quinone oxidoreductase (sqr), dissimilatory sulfite reductase (dsr), reversible dissimilatory sulfite reductase (rdsr), sulfur-oxidizing multienzyme system (sox)(soxXYZA and soxB but lacking soxCD), adenosine phosphosulfate reductase (apr), and ATP sulfurylase (sat). While these genomes share 29 orthologous genes for sulfur oxidation implying that both symbionts possess the same sulfur oxidation pathway, Rma has a rhodanese-related sulfurtransferase putative gene (Rmag0316) that has no corresponding ortholog in Vok, and Vok has one unique dsrR (COSY0782). We propose that Calyptogena symbionts oxidize sulfide and thiosulfate, and that sulfur oxidation proceeds as follows. Sulfide is oxidized to sulfite by rdsr. Sulfite is oxidized to sulfate by apr and sat. Thiosulfate is oxidized to zero-valence sulfur by sox, which is then reduced to sulfide by dsr. In addition, thiosulfate may also be oxidized into sulfate by another component of sox. The result of the RT-PCR showed that genes (dsrA, dsrB, dsrC, aprA, aprB, sat, soxB, and sqr) encoding key enzymes catalyzing sulfur oxidation were all equally expressed in the Vok under three different environmental conditions (aerobic, semioxic, and aerobic under high pressure at 9 MPa), indicating that all sulfur oxidation pathways function simultaneously to support intracellular symbiotic life.
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Affiliation(s)
- Maiko Harada
- Marine Biodiversity Research Program, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology(JAMSTEC), Yokosuka 237-0061, Japan
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Katakura I, Tokunaga M, Matsuo A, Kawaguchi K, Kindo K, Hitomi M, Akahoshi D, Kuwahara H. Development of high-speed polarizing imaging system for operation in high pulsed magnetic field. Rev Sci Instrum 2010; 81:043701. [PMID: 20441339 DOI: 10.1063/1.3359954] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A high-speed polarizing microscope system combined with a 37 T pulse magnet has been developed. This system was applied to successfully visualize the field-induced collapse of charge-orbital ordering in a layered manganite La(1/2)Sr(3/2)MnO(4). Quantitative analyses of the obtained polarizing microscope images provided clear evidence of this transition in contrast to rather moderate changes in magnetization and magnetoresistance. The ability of this system to carry out quantitative analysis was further tested through the observation of Faraday rotation in a Tb(3)Ga(5)O(12) crystal. The Verdet constant determined from the polarizing images is in reasonable agreement with that in literature. Local intensity analyses of the images indicate that we can investigate magneto-optical signals within an accuracy of 0.85% in an area of 9.6 x 9.6 microm(2).
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Affiliation(s)
- I Katakura
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
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Myers CJ, Barker N, Jones K, Kuwahara H, Madsen C, Nguyen NPD. iBioSim: a tool for the analysis and design of genetic circuits. Bioinformatics 2009; 25:2848-9. [DOI: 10.1093/bioinformatics/btp457] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Nagao M, Asaka T, Akahoshi D, Nagai T, Hara T, Kimoto K, Kuwahara H, Matsui Y. Nanoscale structural inhomogeneity at the phase boundary in Nd 1−xSr xMnO 3. Acta Crystallogr A 2008. [DOI: 10.1107/s010876730808361x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Kuwahara H, Takaki Y, Yoshida T, Shimamura S, Takishita K, Reimer JD, Kato C, Maruyama T. Reductive genome evolution in chemoautotrophic intracellular symbionts of deep-sea Calyptogena clams. Extremophiles 2008; 12:365-74. [PMID: 18305898 DOI: 10.1007/s00792-008-0141-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Accepted: 01/07/2008] [Indexed: 10/22/2022]
Abstract
To understand reductive genome evolution (RGE), we comparatively analyzed the recently reported small genomes of two chemoautotrophic, intracellular symbionts of deep-sea clams, Calyptogena okutanii and C. magnifica. Both genomes lack most genes for DNA recombination and repair such as recA and mutY. Their genome architectures were highly conserved except one inversion. Many deletions from small (<100 bp) to large (1-11 kbp) sizes were detected and the deletion numbers decreased exponentially with size. Densities of deletions and short-repeats, as well as A+T content were higher in non-coding regions than in coding regions. Because Calyptogena symbiont genomes lack recA, we propose that deletions and the single inversion occurred by RecA-independent recombination (RIR) at short-repeats with simultaneous consumption of repeats, and that short-repeats were regenerated by accelerated mutations with enhanced A+T bias due to the absence of mutY. We further propose that extant Calyptogena symbiont genomes are in an actively reducing stage of RGE consisting of small and large deletions, and the deletions are caused by short-repeat dependent RIR along with regeneration of short-repeats. In future, the RGE rate will slowdown when the gene repertoires approach the minimum gene set necessary for intracellular symbiotic life.
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Affiliation(s)
- Hirokazu Kuwahara
- Extremobiosphere Research Center, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan
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Kuwahara H, Yoshida T, Takaki Y, Shimamura S, Nishi S, Harada M, Matsuyama K, Takishita K, Kawato M, Uematsu K, Fujiwara Y, Sato T, Kato C, Kitagawa M, Kato I, Maruyama T. Reduced genome of the thioautotrophic intracellular symbiont in a deep-sea clam, Calyptogena okutanii. Curr Biol 2007; 17:881-6. [PMID: 17493812 DOI: 10.1016/j.cub.2007.04.039] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Revised: 04/03/2007] [Accepted: 04/04/2007] [Indexed: 10/23/2022]
Abstract
Although dense animal communities at hydrothermal vents and cold seeps rely on symbioses with chemoautotrophic bacteria [1, 2], knowledge of the mechanisms underlying these chemosynthetic symbioses is still fragmentary because of the difficulty in culturing the symbionts and the hosts in the laboratory. Deep-sea Calyptogena clams harbor thioautotrophic bacterial symbionts in their gill epithelial cells [1, 2]. They have vestigial digestive tracts and nutritionally depend on their symbionts [3], which are vertically transmitted via eggs [4]. To clarify the symbionts' metabolic roles in the symbiosis and adaptations to intracellular conditions, we present the complete genome sequence of the symbiont of Calyptogena okutanii. The genome is a circular chromosome of 1,022,154 bp with 31.6% guanine + cytosine (G + C) content, and is the smallest reported genome in autotrophic bacteria. It encodes 939 protein-coding genes, including those for thioautotrophy and for the syntheses of almost all amino acids and various cofactors. However, transporters for these substances to the host cell are apparently absent. Genes that are unnecessary for an intracellular lifestyle, as well as some essential genes (e.g., ftsZ for cytokinesis), appear to have been lost from the symbiont genome. Reductive evolution of the genome might be ongoing in the vertically transmitted Calyptogena symbionts.
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Affiliation(s)
- Hirokazu Kuwahara
- Extremobiosphere Research Center, Japan Agency for Marine-Earth Science and Technology, 2-15 Yokosuka 237-0061, Japan
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Doukyu N, Yamagishi W, Kuwahara H, Ogino H, Furuki N. Purification and characterization of a maltooligosaccharide-forming amylase that improves product selectivity in water-miscible organic solvents, from dimethylsulfoxide-tolerant Brachybacterium sp. strain LB25. Extremophiles 2007; 11:781-8. [PMID: 17619813 DOI: 10.1007/s00792-007-0096-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Accepted: 06/10/2007] [Indexed: 10/23/2022]
Abstract
A bacterium that secretes maltooligosaccharide-forming amylase in a medium containing 12.5% (vol/vol) dimethylsulfoxide (DMSO) was isolated and identified as Brachybacterium sp. strain LB25. The amylase of the strain was purified from the culture supernatant, and its molecular mass was 60 kDa. The enzyme was stable at pH 7.0-8.5 and active at pH 6.0-7.5. The optimum temperature at pH 7.0 was 35 degrees C in the presence of 5 mM CaCl(2). The enzyme hydrolyzed starch to produce maltotriose primarily. The enzyme was active in the presence of various organic solvents. Its yield and product selectivity of maltooligosaccharides in the presence of DMSO or ethanol were compared with those of the industrial maltotriose-forming amylase from Microbacterium imperiale. Both enzymes improved the production selectivity of maltotriose by the addition of DMSO or ethanol. However, the total maltooligosaccharide yield in the presence of the solvents was higher for LB25 amylase than for M. imperiale amylase.
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Affiliation(s)
- Noriyuki Doukyu
- Department of Life Science,Toyo University, 1-1-1 Izumino, Itakura-machi, Gunma, Japan.
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Harada-Shiba M, Minamino N, Kuwahara H, Itoh T, Maeda R, Ohira M, Abe E, Jinno K, Tomoike H. Th-P15:58 Proteome analysis of hypertriglyceridemic rabbits. ATHEROSCLEROSIS SUPP 2006. [DOI: 10.1016/s1567-5688(06)82018-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Saitoh O, Mizutori Y, Takamura N, Yamasaki H, Kita A, Kuwahara H, Nagayama Y. Adenovirus-mediated gene delivery of interleukin-10, but not transforming growth factor beta, ameliorates the induction of Graves' hyperthyroidism in BALB/c mice. Clin Exp Immunol 2005; 141:405-11. [PMID: 16045729 PMCID: PMC1809459 DOI: 10.1111/j.1365-2249.2005.02874.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta) are well known anti-inflammatory cytokines. We have studied the effect of adenovirus-mediated IL-10 and TGF-beta gene delivery on the induction of Graves' hyperthyroidism in our mouse model that involves repeated injections of adenovirus expressing the thyrotropin receptor A subunit (AdTSHR). We first constructed adenoviruses encoding the two cytokines (AdIL10 and AdTGF(beta)) and confirmed expression by in vitro infection of COS cells. Susceptible BALB/c mice were injected twice with AdTSHR alone or together with AdIL10 or AdTGF(beta), and bled two weeks after the second immunization. Significantly elevated serum thyroxine levels were seen in 26% of mice immunized with AdTSHR and AdIL10 versus 61% with AdTSHR alone. Levels of thyroid stimulating antibody, but not nonstimulating antibody, were also decreased, and TSHR-specific splenocyte secretion of interferon-gamma in recall assays was impaired in mice treated with AdIL10. In contrast, AdTGF(beta) had little effect on hyperthyroidism. Overall, our findings demonstrate that gene delivery of IL-10, but not TGF-beta, suppresses the induction of Graves' hyperthyroidism in a mouse model. However, the effect of IL-10 is less powerful than we observed previously with T helper type 2-inducers including adenovirus expressing IL-4, Shistosoma mansoni infection or alpha-galactosylceramide.
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Affiliation(s)
- O Saitoh
- Department of Medical Gene Technology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
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Doukyu N, Kuwahara H, Aono R. Isolation of Paenibacillus illinoisensis that produces cyclodextrin glucanotransferase resistant to organic solvents. Biosci Biotechnol Biochem 2003; 67:334-40. [PMID: 12728995 DOI: 10.1271/bbb.67.334] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A bacterium that secreted cyclodextrin glucanotransferase (CGTase) in a medium overlaid with n-hexane was isolated and identified as Paenibacillus illinoisensis strain ST-12 K. The CGTase of the strain was purified from the culture supernatant. The molecular mass was 70 kDa. The enzyme was stable at pH 6 to 10 and active at pH 5.0 to 8.0. The optimum temperature at pH 7.0 was 65 degrees C in the presence of 5 mM CaCl2. The enzyme produced mainly beta-cyclodextrin. The total yield of alpha-, beta-, and gamma- cyclodextrins was increased 1.4-fold by the addition of ethanol. In particular, the yield of beta-cyclodextrins in the presence of 10% (vol/vol) ethanol was 1.6-fold that without ethanol. The CGTase was stable and active in the presence of large amounts of various organic solvents.
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Affiliation(s)
- Noriyuki Doukyu
- Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Nagatsuta 4259, Midori-ku, Yokohama 226-8501, Japan.
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Fujita N, Sakamaki H, Uotani S, Takahashi R, Kuwahara H, Kita A, Oshima K, Yamasaki H, Yamaguchi Y, Eguchi K. Acute effects of ethanol on feeding behavior and leptin-induced STAT3 phosphorylation in rat hypothalamus. Int J Obes (Lond) 2003; 27:55-9. [PMID: 12532154 DOI: 10.1038/sj.ijo.0802194] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2002] [Revised: 07/14/2002] [Accepted: 08/13/2002] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Drinking ethanol stimulates the appetite, producing a positive energy balance. The mechanism by which ethanol regulates the appetite in the central nervous system, however, has not been fully understood. The aim of this study is to investigate the interaction of ethanol with the satiety effect of leptin, a hormone which suppresses the appetite in the hypothalamic region. DESIGN : Leptin (7.5 micro g) or the same dose of phosphate buffer saline (PBS) was administered into the third ventricle (i.c.v.), 30 min after an intraperitoneal injection (i.p.) of ethanol (0.5 g/kg body weight) or the same dose of PBS. MATERIALS Adult male Sprague-Dawley rats weighing 290-320 g were used. MEASUREMENTS Food intake was measured 2, 12 and 24 h after leptin i.c.v. infusion. The tyrosine phosphorylation of signal transducer and activator transcription factor 3 (STAT3) in the hypothalamus was analyzed by Western blotting. RESULTS The cumulative food intakes in the saline/leptin group (saline i.p.+leptin i.c.v.) were markedly reduced to about 45% of the saline/PBS group (saline i.p.+PBS i.c.v.) at 2, 12 and 24 h time points (P<0.05, 0.001, and 0.005, respectively). As compared with the saline/leptin group, those of the ethanol/leptin group (ethanol i.p.+leptin i.c.v.) were significantly increased to the level seen in the saline/PBS group at 12 and 24 h time points (P<0.05, and P<0.005 vs the saline/leptin group, respectively). Ethanol administration resulted in about a 50% reduction of the leptin-induced STAT3 tyrosine phosphorylation seen in the hypothalamic protein as compared to that of the saline/leptin group. CONCLUSION These findings suggest that ethanol-induced enhancement of the appetite may, in part, result from leptin resistance transiently caused by ethanol to attenuate the leptin signal transduction.
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Affiliation(s)
- N Fujita
- The First Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan
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Fujita N, Yamasaki H, Yamakawa K, Uotani S, Kuwahara H, Degawa-Yamauchi M, Abe T, Ozaki M, Sera Y, Kawasaki E, Takino H, Yamaguchi Y, Eguchi K. Decrease in the insulin receptor protein level by anti-insulin receptor antibodies: roles of tyrosine kinase activity and receptor internalization. Acta Diabetol 2002; 39:221-7. [PMID: 12486497 DOI: 10.1007/s005920200038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
To investigate the mechanism of severe impairment of insulin action in type B insulin resistance, we extracted IgG from the serum of a patient with type B insulin resistance (B-IgG) and analyzed the inhibiting effect of B-IgG not only on insulin signaling but also on IGF-I signaling in Chinese hamster ovary (CHO) cells expressing human insulin receptor or human IGF-I receptor. Preincubation with 1 mg/ml B-IgG prevented insulin-induced phosphorylation of insulin receptor and insulin receptor substrate-1 (IRS-1) but did not alter the IGF-I-induced phosphorylation of the IGF-I receptor and IRS-1. (125)I-insulin binding was inhibited by 93% after preincubation with B-IgG at 37 degrees C and was recovered up to 50% of the control value by acid washing. However, when cells were preincubated with B-IgG at 4 degrees C, the insulin binding completely recovered the control value by acid washing. (125)I-IGF-I binding was not altered by B-IgG preincubation. Immunoblot study revealed that the protein level of the insulin receptor was strongly decreased by preincubation with 1 mg/ml B-IgG at 37 degrees C, but never at 4 degrees C. The IRS-1 protein level did not change by B-IgG preincubation. In order to know the role of the insulin receptor internalization in the inhibiting effect of B-IgG, we employed CHO cells expressing mutant insulin receptors which do not undergo internalization (CHO-K1018R). B-IgG incubation of CHO-K1018R at 37 degrees C failed to decrease the protein level of the insulin receptor. The present data indicate that IgG from the diabetic patient with type B insulin resistance decreased insulin receptor protein level, probably due to the enhanced degradation rate of the insulin receptor, in which insulin receptor tyrosine kinase activity and internalization are required for this process. This effect of B-IgG was specific for the insulin receptor with no effect on either IGF-I receptor or IRS-1, as reflected by the IGF-I effectiveness on glycemic control in this patient.
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Affiliation(s)
- N Fujita
- The First Department of Internal Medicine, Nagasaki University, School of Medicine, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan
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Asaka T, Anan Y, Nagai T, Tsutsumi S, Kuwahara H, Kimoto K, Tokura Y, Matsui Y. Ferromagnetic domain structures and nanoclusters in Nd(1/2)Sr(1/2)MnO3. Phys Rev Lett 2002; 89:207203. [PMID: 12443504 DOI: 10.1103/physrevlett.89.207203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2002] [Indexed: 05/24/2023]
Abstract
Magnetic domain structures of Nd(1/2)Sr(1/2)MnO3 were investigated by means of low-temperature Lorentz electron microscopy. On cooling, magnetic domain walls started to appear at 250 K, and they were oriented straight along the [100] and [110] directions. With a further decrease in temperature, the volume of each magnetic domain increased with discontinuous domain-wall jumps. A characteristic granular image was observed at around 140 K, near the charge-ordering transition temperature. We consider that this originated from ferromagnetic nanoclusters that appeared in the antiferromagnetic matrix.
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Affiliation(s)
- T Asaka
- Advanced Materials Laboratory (AML), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan
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Li Y, Ren J, Yu W, Li Q, Kuwahara H, Yin L, Carraway KL, Kufe D. The epidermal growth factor receptor regulates interaction of the human DF3/MUC1 carcinoma antigen with c-Src and beta-catenin. J Biol Chem 2001; 276:35239-42. [PMID: 11483589 DOI: 10.1074/jbc.c100359200] [Citation(s) in RCA: 205] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The DF3/MUC1 mucin-like, transmembrane glycoprotein is aberrantly overexpressed in most human carcinomas. The MUC1 cytoplasmic domain interacts with the c-Src tyrosine kinase and thereby increases binding of MUC1 and beta-catenin. In the present work, coimmunoprecipitation studies demonstrate that MUC1 associates constitutively with the epidermal growth factor receptor (EGF-R) in human ZR-75-1 breast carcinoma cells. Immunofluorescence studies show that EGF-R and MUC1 associate at the cell membrane. We also show that the activated EGF-R phosphorylates the MUC1 cytoplasmic tail on tyrosine at a YEKV motif that functions as a binding site for the c-Src SH2 domain. The results demonstrate that EGF-R-mediated phosphorylation of MUC1 induces binding of MUC1 to c-Src in cells. Moreover, in vitro and in vivo studies demonstrate that EGF-R increases binding of MUC1 and beta-catenin. These findings support a novel role for EGF-R in regulating interactions of MUC1 with c-Src and beta-catenin.
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Affiliation(s)
- Y Li
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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Fiebig M, Miyano K, Tomioka Y, Kuwahara H, Tokura Y, Reimann K. Nonlinear magneto-optical properties of colossal magnetoresistive manganites. Phys Rev Lett 2001; 86:6002-6005. [PMID: 11415414 DOI: 10.1103/physrevlett.86.6002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2000] [Indexed: 05/23/2023]
Abstract
Pr(1--x)CaxMnO(3) and Nd(1--x)SrxMnO(3) were investigated with three-photon difference frequency generation (DFG). This method allows one to determine both the crystalline and the magnetic symmetry. In the highly ordered low-temperature phase of Nd(0.50)Sr(0.50)MnO(3), a DFG contribution coupling simultaneously to antiferromagnetic and charge ordering was observed and used to reveal the formation of domains. Thus, magnetically induced three-photon processes are introduced into the fields of both nonlinear magneto-optics and colossal magnetoresistance as a powerful new method.
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Affiliation(s)
- M Fiebig
- Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan.
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Kuwahara H, Tani Y, Ogawa Y, Takaichi Y, Shiraishi A, Ohtsuki M. Therapeutic Effect of Novel Anti-Human Fas Antibody HFE7A on Graft-versus-Host Disease Model. Clin Immunol 2001; 99:340-6. [PMID: 11358429 DOI: 10.1006/clim.2001.5028] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In order to evaluate anti-human Fas antibody, we have established a new graft-versus-host disease (GVHD) model wherein splenocytes of human Fas transgenic mice (hFas-TgM) were transferred to immune-deficient SCID mice. In this model, although host SCID cells are not activated by or responsive to graft hFas-TgM cells, graft hFas-TgM cells are activated by and responsive to host SCID cells and thus cause GVHD symptoms. SCID mice that received hFas-TgM splenocytes had increased human Fas-positive lymphocytes in lymph nodes, decreased in body weight, and developed skin diseases, including rash and alopecia. Administration of novel anti-human Fas antibody HFE7A, which did not induce liver toxicity after administration to mice, decreased the level of the human Fas-positive lymphocytes, blocked the decrease of body weight, and suppressed development of skin diseases in this model. These results indicate that induction of apoptosis to activated graft cells with nontoxic anti-Fas antibody could reduce GVHD symptoms.
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Affiliation(s)
- H Kuwahara
- Neuroscience and Immunology Research Laboratories, Sankyo Co., Ltd., Tokyo, 140-8710, Japan
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Hori T, Sugita Y, Koga E, Shirakawa S, Inoue K, Uchida S, Kuwahara H, Kousaka M, Kobayashi T, Tsuji Y, Terashima M, Fukuda K, Fukuda N. Proposed supplements and amendments to 'A Manual of Standardized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects', the Rechtschaffen & Kales (1968) standard. Psychiatry Clin Neurosci 2001; 55:305-10. [PMID: 11422885 DOI: 10.1046/j.1440-1819.2001.00810.x] [Citation(s) in RCA: 1692] [Impact Index Per Article: 73.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- T Hori
- Department of Behavioral Sciences, Hiroshima University, Japan.
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Hashizume Y, Kuwahara H, Uchimura N, Mukai M, Shirakawa S, Satomura T, Takeuchi N, Tanaka J, Maeda H. Examination of accuracy of sleep stages by means of an automatic sleep analysis system 'Sleep Ukiha'. Psychiatry Clin Neurosci 2001; 55:199-200. [PMID: 11422840 DOI: 10.1046/j.1440-1819.2001.00824.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We examined the differences between the results of an automatic sleep analysis system and inspection decision. Subjects were 10 males (average age 21.6 years). One section consists of 20 s records. The sections that deviated from the algorithm could not be decided. Each sleep stage decided by automatic analysis was compared with the inspection decision. The agreement ratio of stage 3 was 91.6% in the highest, and followed by stage 2, stage 4, stage W and stage 1. The lowest was 62.5% for movement time. The total agreement ratio was 85.8%. The agreement ratios of the apnea index (AI) and the apnea hypopnea index (AHI) were relatively high, but for types of sleep apnea, agreement ratios require improvement.
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Affiliation(s)
- Y Hashizume
- Department of Neuropsychiatry, Kurume University School of Medicine, Fukuoka, Japan.
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Abstract
We report a rare hair follicle nevus that occurred in a three-month-old Japanese boy with mild frontonasal dysplasia. It had been present since birth. Histologically, numerous tiny vellus hair follicles were found within the dermis. The constituent cells of these follicles showed the features of follicular germ cells under the electron microscope. The fibroblasts around the follicles were active and merged with the colloid substance. Many myofibroblasts were found in a collagenous stroma in the atrophic lesion of the frontonasal dysplasia.
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Affiliation(s)
- H Kuwahara
- Department of Plastic and Reconstructive Surgery, Hokkaido University School of Medicine, Sapporo, Japan
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Mukai M, Uchimura N, Takeuchi N, Kuwahara H, Hashizume Y, Nose I, Satomura T, Tanaka J, Maeda H. Study on withdrawal of hypnotics: questionnaire on hypnotic use and its withdrawal. Psychiatry Clin Neurosci 2001; 55:209-10. [PMID: 11422844 DOI: 10.1046/j.1440-1819.2001.00828.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To investigate the situation and problems contingent to hypnotic use and withdrawal, we conducted a questionnaire of outpatients. Only 41% of the patients were satisfied with their sleep and 53% of the patients took hypnotics. As regards the period, 83% of users had used them for more than 1 year and 19% had used them for more than 10 years. Although 90% of patients perceived efficacy of hypnotics, 67% felt more or less anxious about hypnotic use. Sixty-seven per cent of patients had actually withdrawn from the drugs or decreased dosage before. More than half the patients' conditions worsened after the withdrawal or reducing dosage.
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Affiliation(s)
- M Mukai
- Department of Neuropsychiatry, Kurume University, Kurume, Japan.
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Ogawa Y, Kuwahara H, Kimura T, Tani Y, Yonehara S, Shiraishi A, Ohtsuki M. Therapeutic effect of anti-Fas antibody on a collagen induced arthritis model. J Rheumatol 2001; 28:950-5. [PMID: 11361221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
OBJECTIVE To investigate the therapeutic effect of anti-Fas monoclonal antibody (Mab, RK-8) in collagen induced arthritis (CIA). METHODS CD1F1 mice were immunized with bovine type II collagen to induce CIA and were treated with RK-8 intravenously. The effect of RK-8 was monitored by visual scoring. ELISA to detect serum anti-type II collagen antibody was performed on Day 47 and 70. Histopathological analysis was performed on Days 31 and 72. Digital micrography was performed on Day 72. RESULTS RK-8 treatment almost completely prevented CIA. This suppressive effect continued after RK-8 was discontinued. RK-8 significantly suppressed the serum anti-type II collagen antibody level on Day 47. Histological analysis revealed that RK-8 significantly reduced joint histopathology, as determined by the infiltration of inflammatory cells and cartilage damage, consistent with digital micrography. CONCLUSION Administration of anti-Fas Mab may be a useful therapeutic strategy for rheumatoid arthritis if used early in the disease.
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Affiliation(s)
- Y Ogawa
- Neuroscience and Immunology Research Laboratories, Sankyo Co. Ltd., Tokyo, Japan
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Li Y, Kuwahara H, Ren J, Wen G, Kufe D. The c-Src tyrosine kinase regulates signaling of the human DF3/MUC1 carcinoma-associated antigen with GSK3 beta and beta-catenin. J Biol Chem 2001; 276:6061-4. [PMID: 11152665 DOI: 10.1074/jbc.c000754200] [Citation(s) in RCA: 184] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The DF3/MUC1 mucin-like glycoprotein is aberrantly overexpressed in most human carcinomas. The cytoplasmic domain of MUC1 interacts with glycogen synthase kinase 3 beta (GSK3 beta) and thereby decreases binding of MUC1 and beta-catenin. The present studies demonstrate that MUC1 associates with the c-Src tyrosine kinase. c-Src phosphorylates the MUC1 cytoplasmic domain at a YEKV motif located between sites involved in interactions with GSK3 beta and beta-catenin. The results demonstrate that the c-Src SH2 domain binds directly to pYEKV and inhibits the interaction between MUC1 and GSK3 beta. Moreover and in contrast to GSK3 beta, in vitro and in vivo studies demonstrate that c-Src-mediated phosphorylation of MUC1 increases binding of MUC1 and beta-catenin. The findings support a novel role for c-Src in regulating interactions of MUC1 with GSK3 beta and beta-catenin.
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Affiliation(s)
- Y Li
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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Hadase M, Arimoto T, Kuwahara H, Takesako T, Hara H. [Ganglioneuroma detected in a patient over age 60]. Nihon Kokyuki Gakkai Zasshi 2001; 39:182-5. [PMID: 11431911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
We report a case of ganglioneuroma in a 67-year-old woman who presented with an abnormal shadow at a medical examination. She was admitted and chest radiography disclosed a mass in the upper right mediastinum. We suspected a mediastinal tumor after chest CT, chest MRI and bronchofiberscopic examination, and so surgical treatment was performed. The histopathological diagnosis was ganglioneuroma. Ganglioneuroma is thought of as a children's disease and adult onset is rare. We reasoned that ganglioneuroma should be included among the mediastinal tumors in patients over 60.
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Affiliation(s)
- M Hadase
- Department of Respiratory Medicine, Kyoto Second Red Cross Hospital 355-5, Haruobi-cho, Kamanza-dori, Marutamachi-agaru, Kamigyo-ku, Kyoto 602-8026, Japan
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Arimoto T, Kuwahara H, Hadase M, Fujii S, Takesako T, Hara H. [Results of questionnaire on open disclosure to patients with malignant lung tumors comparison of responses before and after chemotherapy]. Nihon Kokyuki Gakkai Zasshi 2001; 39:89-94. [PMID: 11321832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
To investigate patient attitudes towards open disclosure of malignant disease, we conducted a questionnaire survey of 17 patients with malignant lung tumors, to whom the nature of their disease was revealed. The questionnaire used a 100 mm analog scale. Ten of the patients were treated by chemotherapy and their questionnaire results before and after treatment were compared. It was found that they were mostly satisfied about being truthfully informed and that, indeed, they were anxious to know their true diagnoses. They were also keen to have their true prognosis revealed, but not as much as the diagnosis. They also wished to be informed about treatment and its effects. These attitudes showed no marked changes resulting from the administration of chemotherapy, and we therefore concluded that chemotherapy itself had no influence on patients' feelings about disclosure. The questionnaire was well accepted and was useful in judging attitudes to open disclosure.
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Affiliation(s)
- T Arimoto
- Department of Respiratory Medicine, Kyoto Second Red Cross Hospital, 355-5, Haruobi-tyo, Kamanza-doori Marutamachi, Kamigyo-ku, Kyoto, Japan, 602-8226
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50
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Lao LM, Kumakiri M, Kiyohara T, Kuwahara H, Ueda K. Sub-populations of melanocytes in pigmented basal cell carcinoma: a quantitative, ultrastructural investigation. J Cutan Pathol 2001; 28:34-43. [PMID: 11168750 DOI: 10.1034/j.1600-0560.2001.280104.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Pigmentation is a characteristic clinical feature of basal cell carcinomas (BCCs) in Japanese patients. The pathogenesis of melanin pigment in pigmented BCCs is poorly understood. METHODS We have combined the techniques of morphometric analysis and electron microscopy to assess accurately the morphologic aspects of melanocytes that occurred in pigmented and non-pigmented areas of pigmented BCCs. RESULTS In the pigmented areas melanocytes were not only located along the basal membrane but also interspersed between tumor cells in the central parts of the tumor nest, and had large and numerous dendrites. Those in a supra-basal location displayed some degree of degeneration due to mitochondrion and melanosome swelling. In the non-pigmented areas melanocytes were only basally located, showed fewer dendrites, and frequently showed abortive melanosomes. However, melanocytes in these two different portions were in the active state of melanogenesis and proliferation. Ultrastructural cytomorphometric analysis also showed significant differences in most of the nuclear and cell parameters including nuclear and cell area, the nuclear/cell area ratio, cell perimeter and cell form factor between these two types of melanocytes. Particularly melanocytes in the pigmented areas were twice the cell size of the latter. In addition, the melanosomes remained almost completely in the apoptotic tumor cells, and the phagocytosis of the melanosome-containing apoptotic cells by the neighboring tumor cells appeared to be followed by the formation of the melanosome complexes. CONCLUSIONS These findings suggest that different populations of melanocytes are probably present in pigmented BCCs, and repeated cycles of phagocytosis of melanosome-containing apoptotic cells may represent the predominant way of forming large melanosome complexes. The present morphological observation and quantitative analysis provide a morphological basis for further studies to interpret other pathologic changes in pigmented BCCs.
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Affiliation(s)
- L M Lao
- Department of Dermatology, Fukui Medical University, Japan
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