Coordinated motion of multiple eukaryotic flagella revealed from sperm packets of the colonial volvocine alga

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20661
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0702:Biology at cellular to organismal levels, and related fields
• Research Institution: Gakushuin University
• Principal Investigator: Kage Azusa 学習院大学, 理学部, 助教 (10748809)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: 真核生物鞭毛 / 可視化 / メタクロナルウェーブ / 集団運動

Outline of Final Research Achievements

To clarify the relationship between the movement of a number of flagella/cilia and that of individual flagellum/cilium, we visualized swimming and flagellar motion of sperm packets of the volvocine green alga Pleodorina starrii. A dark-field microscope and a high-speed camera were equipped to visualize free swimming. For detailed visualization of flagellar motion, a system was constructed to capture sperm packets with a glass micropipette. Sperm packets swam approximately 1.4 times faster than asexual colonies of the same male strain. Asexual colonies and sperm packets showed ciliary-type flagellar movement, while dissociated single sperm showed flagellar-type movement. The switching mechanism of the flagellar movement during the process of sperm packet disassembly into single sperm was suggested.

Free Research Field

生物物理学

Academic Significance and Societal Importance of the Research Achievements

本研究は群体性ボルボックス目緑藻精子束の運動を初めて定量的に解明した。その結果、無性群体と精子束では鞭毛の分布が異なること、精子束と分解した単体精子では鞭毛運動のパターンが異なることを明らかにした。群体性ボルボックス目緑藻の有性生殖の過程における鞭毛運動の意義を明らかにすることができ、鞭毛・繊毛運動と藻類学にまたがる学術的意義を持つ。さらに、低レイノルズ数環境中で動作するマイクロロボットの開発などの応用にもつながる成果である。