Development of 3-pulse super-resolution microscope and its applications for the visualization of the early events of photosynthesis.

2019 Fiscal Year Final Research Report

• Project/Area Number: 15H03679
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: Osaka City University
• Principal Investigator: Sugisaki Mitsuru 大阪市立大学, 大学院理学研究科, 准教授 (20360042)
• Co-Investigator(Kenkyū-buntansha): 近藤 政晴 名古屋工業大学, 工学(系)研究科(研究院), 助教 (20571219) ; 出羽 毅久 名古屋工業大学, 工学(系)研究科(研究院), 教授 (70335082)
• Project Period (FY): 2015-04-01 – 2020-03-31
• Keywords: 光合成 / 顕微鏡法

Outline of Final Research Achievements

The super-resolution microscopic methodology has been investigated to observe photosynthetic specimens with a spatial resolution beyond the so-called diffraction limit. By means of the laser scanning GSD microscopy, microscopic images of auto-fluorescence from chloroplasts in green algae have been successfully obtained with a spatial resolution of 100nm. On the other hands, unusual increase in fluorescence efficiency of chlorophyll a was observed when the STED microscopy has been employed, while the non-radiative depopulation of the excited state is expected mainly via the stimulated emission process. This anomaly comes from the anti-Stokes fluorescence, probably due to an efficient involvement of low-frequency vibrational modes. Further, 3-pulse four-wave mixing signals pumped with chirped pulses have been examined, where selective excitations of phonon modes and the control of the coupling strength between a photosynthetic pigment and solvent have been attained.

Free Research Field

生体物性物理学

Academic Significance and Societal Importance of the Research Achievements

本研究では，試料の構造に加え，その機能を，高い空間分解能で同時観測する手法の獲得を目指した．これまで広く一般的に行われてきた方法とは異なり，天然の状態のままの緑藻を測定試料とし，試料を染色せずに，超解像度顕微鏡画像の取得に成功したことに意義がある．また，空間分解能に制限がないとされてきた超解像度顕微鏡法において，これまでの常識を覆す真逆の結果が得られ，その機構を解明した点も重要である．