Study on the photosymbiosis between cyanobacteria and planktonic protozoa

• Project/Area Number: 16K00532
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental dynamic analysis
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: FUJIKI Tetsuichi 国立研究開発法人海洋研究開発機構, 地球環境観測研究開発センター, 主任技術研究員 (30598248)
• Co-Investigator(Kenkyū-buntansha): 木元 克典 国立研究開発法人海洋研究開発機構, 地球環境観測研究開発センター, 主任技術研究員 (40359162) ; 石谷 佳之 筑波大学, 計算科学研究センター, 研究員 (60772043)
• Research Collaborator: TAKAGI Haruka ; UEDA Masato
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2017: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000); Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: 細胞内共生 / FRR法 / 原生動物 / 原核藻類 / 光合成 / 生物海洋

Outline of Final Research Achievements

Cyanobacteria-bearing planktic protozoans are newly discovered in the euphotic zone of the tropical and subtropical ocean. In the present study, we improved the fast-repetition-rate fluorometry to examine the photosynthetic activity of symbiotic cyanobacteria within host planktic protozoan. In addition, we succeeded in isolating the cyanobacteria from the planktic protozoan and revealed the photosynthetic characteristics of symbiotic cyanobacteria.

Academic Significance and Societal Importance of the Research Achievements

ラン藻には、光合成システム、窒素固定、嫌気代謝、従属栄養性などの生理的性質に様々なものいることが知られている。しかし、原生動物の体内から新たに発見されたラン藻の生理特性や宿主との関係については全く不明である。本研究で開発した手法を用いて、ラン藻と原生動物の関係を明らかにすることで、まだまだ謎の多い海洋での細胞内共生という現象の解明に新たな知見を与えることができる可能性がある。

Research Products

• [Journal Article] Phylogeography of the pelagic snail Limacina helicina (Gastropoda: Thecosomata) in the subarctic western North Pacific (2018)
  • Author(s): Shimizu Keisuke、Kimoto Katsunori、Noshita Koji、Wakita Masahide、Fujiki Tetsuichi、Sasaki Takenori
  • Journal Title: Journal of Molluscan Studies Volume: 84 Issue: 1 Pages: 30-37
  • DOI: 10.1093/mollus/eyx040
  • Peer Reviewed / Open Access
• [Journal Article] Effect of nutritional condition on photosymbiotic consortium of cultured Globigerinoides sacculifer (Rhizaria, Foraminifera) (2018)
  • Author(s): Takagi Haruka、Kimoto Katsunori、Fujiki Tetsuichi、Moriya Kazuyoshi
  • Journal Title: Symbiosis Volume: 印刷中 Issue: 1 Pages: 25-39
  • DOI: 10.1007/s13199-017-0530-3
  • Peer Reviewed / Open Access
• [Presentation] FRR法を用いた浮遊性原生動物と藻類の共生関係の解明 (2018)
  • Author(s): 藤木徹一、木元克典、高木悠花、石谷佳之
  • Organizer: 名古屋大学宇宙地球環境研究所研究集会
• [Presentation] Disclosing photosymbiosis in modern planktic foraminifers (2018)
  • Author(s): Haruka Takagi, Tetsuichi Fujiki, Katsunori Kimoto, Kazuyoshi Moriya, Hiroaki Saito
  • Organizer: FORAMS2018
  • Int'l Joint Research
• [Presentation] Experimental study of growth and photophysiology of Globigerinoides sacculifer to understand host-symbiont nutritional interactions (2018)
  • Author(s): Haruka Takagi, Tetsuichi Fujiki, Katsunori Kimoto, Kazuyoshi Moriya
  • Organizer: FORAMS2018
  • Int'l Joint Research
• [Presentation] Phylogenomic approach to the early evolution of Foraminifera (2018)
  • Author(s): Yoshiyuki Ishitani, Yurika Ujiie, Euki Yazaki, Takashi Toyofuku, Yukiko, Nagai, Yuji Inagaki
  • Organizer: FORAMS2018
  • Int'l Joint Research
• [Presentation] 化石に残るプランクトン浮遊性有孔虫～その生き様を探る～ (2018)
  • Author(s): 高木悠花
  • Organizer: 海洋生物シンポジウム2018
  • Invited
• [Presentation] Carbon fixation by endosymbiotic algae within protistan microzooplankton (2017)
  • Author(s): Haruka Takagi, Katsunori Kimoto, Tetsuichi Fujiki and Hiroaki Saito
  • Organizer: JpGU-AGU Joint Meeting 2017
  • Int'l Joint Research
• [Presentation] Development of a fast repetition rate fluorometer for autonomous ocean observation platforms (2017)
  • Author(s): Tetsuichi Fujiki, Naomi Harada, Hideshi Kimoto, Kensuke Watari and Yasuhisa Ishihara
  • Organizer: AQUAFLUO II Chlorophyll Fluorescence in Aquatic Sciences
  • Int'l Joint Research
• [Presentation] Light dependent photophysiology and carbon fixation in symbiont bearing planktic foraminifers (2017)
  • Author(s): Haruka Takagi, Tetsuichi Fujiki and Katsunori Kimoto
  • Organizer: AQUAFLUO II Chlorophyll Fluorescence in Aquatic Sciences
  • Int'l Joint Research
• [Presentation] Speciation and dispersal pattern of marine protists in the vertical dimension (2017)
  • Author(s): Yoshiyuki Ishitani, Yurika Ujiie, Yuji Inagaki and Kiyotaka Takishita
  • Organizer: InterRad XV
  • Int'l Joint Research
• [Presentation] Molecular marker to identify radiolarian species -toward establishment of paleoenvironmental proxy- (2017)
  • Author(s): Yoshiyuki Ishitani
  • Organizer: AGU Fall Meeting 2017
  • Int'l Joint Research
• [Presentation] いがいと流されない海の原生生物 (2017)
  • Author(s): 石谷佳之
  • Organizer: 原生生物学会＆共生生物学会合同シンポジウム
  • Invited
• [Presentation] 単細胞ってすばらしい!! (2016)
  • Author(s): 石谷佳之
  • Organizer: 東京大学大気海洋研究所オープンキャンパス
  • Place of Presentation: 東京大学大気海洋研究所 (千葉県柏市)
  • Year and Date: 2016-10-22
• [Presentation] 浮遊性有孔虫各種の光共生性と光合成生理特性 (2016)
  • Author(s): 高木悠花、木元克典、藤木徹一、守屋和佳
  • Organizer: 日本海洋学会2016年度秋季大会
  • Place of Presentation: 鹿児島大学 (鹿児島県鹿児島市)
  • Year and Date: 2016-09-13
• [Book] アメーバのはなし －原生生物・人・感染症－ (2018)
  • Author(s): 永宗喜三郎、島野智之、矢吹彬憲、丸山真一朗、八木田健司、福田康弘、中井裕、伊藤章、小林富美惠、野田悟子、平川泰久、白鳥峻志、廣岡裕吏、雪吹直史、松崎素道、石谷佳之、土屋正史、神川龍馬、中山卓郎、菅裕
  • Total Pages: 152
  • Publisher: 朝倉書店
  • ISBN: 9784254171686