A joint research group led by Professor Shiro Itoi of the College of Bioresource Sciences, Nihon University, including Professor Hajime Matsubara of the Faculty of Biological Science and Technology, Institute of Science and Engineering, Kanazawa University, and Professor Nobuo Suzuki of the Institute of Nature and Environmental Technology, Kanazawa University, together with researchers from the University of Tokyo, Nagoya University, and Niigata Prefectural Kaiyo High School, has revealed that larvae of the grass puffer (Takifugu alboplumbeus) defend themselves against predators not only with the potent toxin tetrodotoxin (TTX) but also with 5,6,11-trideoxytetrodotoxin (TDT), a TTX analog with almost no toxicity.
In this study, using whole-mount immunohistochemistry, a technique that renders tissues transparent for observation, the group demonstrated that maternally derived TDT, like TTX, is localized to the body surface (epidermis) of the larvae.
Furthermore, recent studies have shown that pufferfish themselves detect TDT as an odorant and are attracted to it. The present study thus highlights the remarkable dual role of TDT: it functions as a “danger signal” to predators while serving as a “social signal” among pufferfish.
These findings are expected to contribute to elucidating the complex and sophisticated survival strategies that enable pufferfish to survive the larval stage, when they are most vulnerable.
This study was conducted as part of the Cooperative Research Program of the Institute of Nature and Environmental Technology, Kanazawa University, led by Professor Nobuo Suzuki as principal investigator (Project Nos. 23032, 24025, and 25027), and JSPS KAKENHI Grants-in-Aid for Scientific Research (A) (Grant Nos. 19H00954 and 23H00347), among others. Professor Hajime Matsubara (Aquatic Reproductive biology of aquatic species) and Professor Nobuo Suzuki (Environmental Physiology) contributed to the purification of TDT and TTX in this study.
The findings were published online in the international scientific journal "iScience" on August 19, 2026.
Figure: TDT-based survival strategy of pufferfish larvae
Click here to see the press release【Japanese only】
Journal : iScience
研究者情報：Hajime Matsubara
Nobuo Suzuki
Related Information
School of Biological Science and Technology, College of Science and Engineering, Kanazawa University
Graduate School of Natural Science and Technology, Kanazawa University
Institute of Nature and Environmental Technology, Kanazawa University
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