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The molecular mechanisms of Toxoplasma gondii and Neospora caninum reactivation from latency.

Research Project

Project/Area Number 20H03149
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Review Section Basic Section 42020:Veterinary medical science-related
Research InstitutionGifu University

Principal Investigator

Takashima Yasuhiro  岐阜大学, 応用生物科学部, 准教授 (20333552)

Co-Investigator(Kenkyū-buntansha) 山本 雅裕  大阪大学, 微生物病研究所, 教授 (00444521)
Project Period (FY) 2020-04-01 – 2024-03-31
Project Status Completed (Fiscal Year 2023)
Budget Amount *help
¥17,550,000 (Direct Cost: ¥13,500,000、Indirect Cost: ¥4,050,000)
Fiscal Year 2022: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2021: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2020: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Keywordsトキソプラズマ / ネオスポラ / 潜伏 / シスト / 活性化
Outline of Research at the Start

偏性細胞内寄生性のトキソプラズマ、ネオスポラのシストが何らかの理由で宿主細胞外に放出されることが活性化のきっかけであるという仮説を立てた。予備実験として、感染マウスの脳神経細胞から取り出したシストを細胞外液あるいは細胞内液を模したイオン組成の液体中で培養したところ、細胞外液を模した液中では「宿主細胞から取り出したシスト」が直ちに活性化した。上記のようなin vitroレベルの成果にもとづき、本研究ではトキソプラズマ症・ネオスポラ症発症のきっかけになる因子を宿主生体組織内で同定するとともに、その因子を認識する原虫側の機構を解明する。

Outline of Final Research Achievements

The study revealed that activation of Toxoplasma gondii from the latent state is induced when the concentrations of sodium, potassium, and calcium ions in the microenvironment around the latent worms meet certain conditions. These conditions were similar to those outside the host cell, suggesting that cysts formed inside the host cell are released outside the cell to trigger reactivation. In fact, reactivation occurred when cysts inside the host cell were physically removed from the cell. The results also indicated that the protozoan calcium channels are necessary for these reactions.

Translated with DeepL.com (free version)

Academic Significance and Societal Importance of the Research Achievements

人獣共通感染症であるトキソプラズマは、感染したからと言って直ちに発症することはまれである。いっぽう、免疫不全などにより潜伏中の虫体が再活性化すると脳炎などの重篤な障害につながることがある。これまで潜伏から再活性化に至るメカニズムは不明であったが、本研究でこれが明らかとなった。このため人、あるいは家畜に潜伏感染している本原虫の再活性化を防ぐための基盤となる知見が得られたと言える。

Report

(4 results)
  • 2023 Final Research Report ( PDF )
  • 2022 Annual Research Report
  • 2021 Annual Research Report
  • 2020 Annual Research Report
  • Research Products

    (4 results)

All 2023 2021

All Journal Article (3 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 3 results,  Open Access: 2 results) Presentation (1 results)

  • [Journal Article] Prevalence of Toxoplasma gondii infection among small mammals in Tatarstan, Russian Federation2021

    • Author(s)
      Nikolai D. Shamaev, Eduard A. Shuralev, Oleg V. Nikitin, Malik N. Mukminov, Yuriy N. Davidyuk, Alexander N. Belyaev, Guzel Sh. Isaeva, Vasil B. Ziatdinov, Nail I. Khammadov, Regina F. Safina, Gaysha R. Salmanova, Guzel M. Akhmedova, Kamil S. Khaertynov, Taizo Saito, Katsuya Kitoh, Yasuhiro Takashima
    • Journal Title

      Sci Rep.

      Volume: 11 Issue: 1

    • DOI

      10.1038/s41598-021-01582-y

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Spatial distribution of anti-Toxoplasma gondii antibody-positive wild boars in Gifu Prefecture, Japan2021

    • Author(s)
      Taizo Saito, Yuko Kitamura, Eiji Tanaka, Itsuki Ishigami, Yuji Taniguchi, Junji Moribe, Katsuya Kitoh, Yasuhiro Takashima
    • Journal Title

      Sci Rep.

      Volume: 10 Issue: 1

    • DOI

      10.1038/s41598-021-96758-x

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Releasing latent Toxoplasma gondii cysts from host cells to the extracellular environment induces excystation2021

    • Author(s)
      Taizo Saito, Tatsunori Masatani, Katsuya Kitoh, YasuhiroTakashima
    • Journal Title

      Int. J. Parasitol.

      Volume: 51 Issue: 12 Pages: 999-1006

    • DOI

      10.1016/j.ijpara.2021.04.004

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed
  • [Presentation] 強毒株1型Toxoplasma gondiiに対するヨーロッパモリネズミの耐性2023

    • Author(s)
      石田碧、Nikolai shamaev、越本知大、篠原明男、名倉悟郎、高島康弘
    • Organizer
      第92回日本寄生虫学会大会
    • Related Report
      2022 Annual Research Report

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Published: 2020-04-28   Modified: 2025-01-30  

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