Characteristic physiology and ecology of a protozoan parasite Perkinsus olseni prevailing in wild stocks of Manila clam

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H03858
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Aquatic bioproduction science
• Research Institution: The University of Tokyo
• Principal Investigator: Itoh Naoki 東京大学, 大学院農学生命科学研究科(農学部), 准教授 (30502736)
• Co-Investigator(Kenkyū-buntansha): 良永 知義 東京大学, 大学院農学生命科学研究科(農学部), 教授 (20345185) ; 高橋 計介 東北大学, 農学研究科, 准教授 (80240662)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 原虫 / 二枚貝類 / 生体防御 / 宿主特異性 / 培養 / 栄養要求性 / 宿主寄生虫間相互関係 / Perkinsus olseni

Outline of Final Research Achievements

A protozoan parasite Perkinsus olseni is prevailing in wild stocks of Manila clam in Japan, and this research project aimed at understanding physiological and ecological adaptation of P. olseni to the host species. In this study, P. olseni were characterized physiologically and ecologically, and we clarified that the proliferation of P. olseni was not inhibited by host bivalves, and that production of the major infective stage increased in warmer season when mass mortality of Manila clams often occurs. These characters are considered to be parts of advantages for P. olseni to prevail in Manila clam stocks in Japan. We also examined host specificity and geographical distribution, and established an in vitro isolate of the related comparative species, P. beihaiensis, in Japan. In future, these information and research materials would be useful to reveal further physiological and ecological adaptation of P. olseni to the host species.

Free Research Field

魚病学

Academic Significance and Societal Importance of the Research Achievements

Perkinsus属原虫は重要水産生物である二枚貝生産を脅かす寄生生物であり、本研究対象であるP. olseniは国際獣疫事務局による指定を受けた重要病原体である。本研究では本種が国内アサリ資源への蔓延に至った生理・生態学的特徴の一端を解明することに成功、加えて研究ツールの開発や新たな生活サイクルの提唱にも至った。これらの成果は本種による疾病を克服し安定的な二枚貝生産へ貢献すると考えられる。