TAKAHASHI Shunichi

写真a

Title

Professor

Researcher Number(JSPS Kakenhi)

80620153

Laboratory Address

3422 Sesoko, Motobu, Okinawa 905-0227, Japan

Mail Address

E-mail address

Laboratory Phone number

+81-98-047-2997
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Current Affiliation Organization 【 display / non-display 】

  • Duty   University of the Ryukyus   Tropical Biosphere Research Center   Professor  

  • Concurrently   University of the Ryukyus   Graduate School of Engineering and Science   Professor  

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University 【 display / non-display 】

  • 1993.04
    -
    1997.03

    University of the Ryukyus   Faculty of Science   Graduated

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Graduate School 【 display / non-display 】

  • 1997.04
    -
    1999.03

    University of the Ryukyus  Graduate School, Division of Science and Engineering  Master's Course  Completed

  • 1999.04
    -
    2002.03

    University of the Ryukyus  Graduate School, Division of Science and Engineering  Doctor's Course  Completed

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External Career 【 display / non-display 】

  • 2002.04
    -
    2003.03

     

  • 2003.04
    -
    2006.03

    National Institute for Basic Biology  

  • 2006.04
    -
    2008.03

    Australian National University  

  • 2008.04
    -
    2010.12

    Australian National University  

  • 2011.01
    -
    2014.09

    Australian National University  

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Affiliated academic organizations 【 display / non-display 】

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    THE JAPANESE SOCIETY OF PHOTOSYNTHESIS RESEARCH 

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    JAPANESE CORAL REEF SOCIETY 

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    International Society of Photosynthesis Research 

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    International Society for Reef Studies 

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Research Interests 【 display / non-display 】

  • サンゴ

  • 褐虫藻

  • 共生

  • 白化

  • 地球温暖化

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Research Areas 【 display / non-display 】

  • Life Science / Ecology and environment

  • Life Science / Aquatic bioproduction science

  • Life Science / Plant molecular biology and physiology

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Published Papers 【 display / non-display 】

  • Environmental pH signals the release of monosaccharides from cell wall in coral symbiotic alga

    Yuu Ishii, Hironori Ishii, Takeshi Kuroha, Ryusuke Yokoyama, Ryusaku Deguchi, Kazuhiko Nishitani, Jun Minagawa,Masakado Kawata, Shunichi Takahashi, Shinichiro Maruyama

    eLife   12   e80628   2023.08 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

    • Access this article
      DOI

  • Moonrise timing is key for synchronized spawning in coral Dipsastraea speciosa

    Che-Hung Lin, Shunichi Takahashi, Aziz J. Mulla, Yoko Nozawa

    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA ( NATL ACAD SCIENCES )  118 ( 34 )   2021.08 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

    　View Summary

    Synchronized mass coral spawning typically occurs several days after a full moon once a year. It is expected that spawning day is determined by corals sensing environmental change regulated by the lunar cycle (i.e., tide or moonlight); however, the exact regulatory mechanism remains unknown. Here, we demonstrate how moonlight influences the spawning process of coral, Dipsastraea speciosa. When corals in the field were shaded 1 and 3 d before the full moon or 1 d after the full moon, spawning always occurred 5 d after shading commenced. These results suggest moonlight suppresses spawning: a hypothesis supported by laboratory experiments in which we monitored the effects of experimental moonlight (night-light) on spawning day. Different night-light treatments in the laboratory showed that the presence of a dark period between day-light and night-light conditions eliminates the suppressive effect of night-light on spawning. In nature, moonrise gets progressively later during the course of the lunar cycle, shifting to after sunset following the day of the full moon. Our results indicate that this period of darkness between sunset and moonrise triggers synchronized mass spawning of D. speciosa in nature.

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  • Photo-movement of coral larvae influences vertical positioning in the ocean

    Aziz J. Mulla, Che-Hung Lin, Shunichi Takahashi, Yoko Nozawa

    CORAL REEFS ( SPRINGER )  40 ( 4 ) 1297 - 1306   2021.08 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

    　View Summary

    Behaviour can have profound consequences for the dispersal potential of an organism. In the marine environment, larvae rely heavily on oceanic currents to migrate from one area to another. As oceanic currents are faster in the shallows, the vertical positioning of larvae during dispersal is a key factor regulating the distance individuals can travel. Up until now, the vertical positioning of coral larvae has been largely explained by buoyancy, as well as changes in physical and chemical cues. However, here we show that in larvae of coral Pocillopora verrucosa, vertical positioning is influenced by photo-movement. We examined the reaction to light of five coral species in the laboratory and found that only larvae of P. verrucosa, but not other species, displayed a positive photo-response (i.e. an accumulation of larvae close to the light source). This reaction was observed irrespective to the orientation of light from the top, bottom or side. In the field, P. verrucosa larvae accumulated in the top halves of transparent chambers at all depths (1, 7, 15 m), whereas such behaviour failed to occur in dark chambers. Our results demonstrate that light can play an important role for coral larvae to regulate vertical positioning during dispersal and provides a hypothesis that positive photo-movement might allow larvae to disperse further and contribute to the wide geographical distribution of P. verrucosa in the Indo-Pacific.

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  • Chloroplast acquisition without the gene transfer in kleptoplastic sea slugs, Plakobranchus ocellatus

    Maeda T, Takahashi S, Yoshida T, Shimamura S, Takaki Y, Nagai Y, Toyoda A, Suzuki Y, Arimoto A, Ishii H, Satoh N, Nishiyama T, Hasebe M, Maruyama T, Minagawa J, Obokata J, Shigenobu S

    eLife ( ELIFE SCIENCES PUBLICATIONS LTD )  10   10:e60176   2021.04 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

    　View Summary

    Some sea slugs sequester chloroplasts from algal food in their intestinal cells and photosynthesize for months. This phenomenon, kleptoplasty, poses a question of how the chloroplast retains its activity without the algal nucleus. There have been debates on the horizontal transfer of algal genes to the animal nucleus. To settle the arguments, this study reported the genome of a kleptoplastic sea slug, Plakobranchus ocellatus, and found no evidence of photosynthetic genes encoded on the nucleus. Nevertheless, it was confirmed that light illumination prolongs the life of mollusk under starvation. These data presented a paradigm that a complex adaptive trait, as typified by photosynthesis, can be transferred between eukaryotic kingdoms by a unique organelle transmission without nuclear gene transfer. Our phylogenomic analysis showed that genes for proteolysis and immunity undergo gene expansion and are up-regulated in chloroplast-enriched tissue, suggesting that these molluskan genes are involved in the phenotype acquisition without horizontal gene transfer.

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  • Loss of symbiont infectivity following thermal stress can be a factor limiting recovery from bleaching in cnidarians

    Kishimoto Mariko, Baird Andrew H., Maruyama Shinichiro, Minagawa Jun, Takahashi Shunichi

    ISME JOURNAL ( SPRINGERNATURE )  14 ( 12 ) 3149 - 3152   2020.12 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

    　View Summary

    Increases in seawater temperature can cause coral bleaching through loss of symbiotic algae (dinoflagellates of the family Symbiodiniaceae). Corals can recover from bleaching by recruiting algae into host cells from the residual symbiont population or from the external environment. However, the high coral mortality that often follows mass-bleaching events suggests that recovery is often limited in the wild. Here, we examine the effect of pre-exposure to heat stress on the capacity of symbiotic algae to infect cnidarian hosts using the Aiptasia (sea-anemone)-Symbiodiniaceae model system. We found that the symbiont strainBreviolumsp. CS-164 (ITS2 type B1), both free-living and in symbiosis, loses the capacity to infect the host following exposure to heat stress. This loss of infectivity is reversible, however, a longer exposure to heat stress increases the time taken for reversal. Under the same experimental conditions, the loss of infectivity was not observed in another strainBreviolum psygmophilumCCMP2459 (ITS2 type B2). Our results suggest that recovery from bleaching can be limited by the loss of symbiont infectivity following exposure to heat stress.

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Presentations 【 display / non-display 】

  • Adaptation of corals to future warm environments

    高橋 俊一

    Seminar (Academia Sinica)  2018  -  2018 

  • Mechanisms for initiating coral-Symbiodinium symbiosis

    高橋 俊一

    An Australian Academy of Science Boden Research Conference  2018  -  2018 

  • Size-dependent symbiont specificity in cnidarian-dinoflagellate symbiosis

    高橋 俊一

    The 13th International Colloquium on Endocytobiology and Symbiosis  2016  -  2016 

  • Saving coral reefs: an arranged marriage in alga-coral symbiosis

    高橋 俊一

    第33回つくば藻類・プロティストフォーラム  2014  -  2014 

  • Photoinhibition and photoprotection under excessive light conditions

    高橋 俊一

    Symposium “New paradigm in photoinhibition research”, the 54th Annual Meeting of the Japanese Society of Plant Physiologists  2013  -  2013 

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Grant-in-Aid for Scientific Research 【 display / non-display 】

  • Grant-in-Aid for Scientific Research(A)

    Project Year: 2023.04  -  2027.03 

    Direct: 36,200,000 (YEN)  Overheads: 10,860,000 (YEN)  Total: 47,060,000 (YEN)

  • Grant-in-Aid for JSPS Fellows

    Project Year: 2023.04  -  2025.03 

    Direct: 2,400,000 (YEN)  Total: 2,400,000 (YEN)

  • Grant-in-Aid for Scientific Research(B)

    Project Year: 2022.04  -  2025.03 

    Direct: 13,400,000 (YEN)  Overheads: 17,420,000 (YEN)  Total: 4,020,000 (YEN)

  • Elucidation of synchronized spawning mechanism in corals

    Grant-in-Aid for JSPS Fellows

    Project Year: 2022.04  -  2024.03 

    Direct: 2,300,000 (YEN)  Overheads: 2,300,000 (YEN)  Total: 0 (YEN)

  • Unveiling the mechanism of phase-shift in coral reef ecosystem focusing on extracellular degradation system in corals

    Grant-in-Aid for Scientific Research(A)

    Project Year: 2020.04  -  2024.03 

    Direct: 34,500,000 (YEN)  Overheads: 44,850,000 (YEN)  Total: 10,350,000 (YEN)

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Other External funds 【 display / non-display 】

  • Project Year: 2012  -  2014 

    Member: TAKAHASHI Shunichi  Offer Organization: Australian Research Council

    Total: 30,000,000 (YEN)

  • Project Year: 2011.01  -  2015.12 

    Member: TAKAHASHI Shunichi  Offer Organization: Australian Research Council

    Total: 60,000,000 (YEN)

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SDGs 【 display / non-display 】

  • 　サンゴ礁に生息するサンゴは、体の中に褐虫藻と呼ばれる藻類を共生させています。これにより、サンゴは動物でありながら、光（光合成）で栄養を得ることができます。しかし、海水温の上昇によるサンゴの白化（褐虫藻の喪失）が起こると、サンゴは栄養不足となり餓死します。地球温暖化に伴い、「サンゴの白化」と「サンゴ礁生態系の崩壊」が地球規模の問題となっており、早急の解決が望まれています。

    　サンゴの白化の起こりやすさは、共生する褐虫藻の種類によりことなります。そのため、サンゴは高温に適した褐虫藻種を共生させることで、白化を回避することができます。しかし、自然界では、これが簡単には起こりません。そこで私の研究室では、サンゴが高温に適した褐虫藻種を効率よく獲得する技術の開発を進めています。この技術は、「サンゴの白化抑制」や「サンゴ礁生態系の保全」に役立つと期待されます。

    　本研究プロジェクトを支援・協力する企業を募集しています。興味があれば、高橋までご連絡ください。

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