Reconstruction of chemotaxis model of bacteria by observing the flagellar movement and prediction of the collective movement

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04193
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 19010:Fluid engineering-related
• Research Institution: Tottori University
• Principal Investigator: NAKAI Tonau 鳥取大学, 工学研究科, 准教授 (80452548)
• Co-Investigator(Kenkyū-buntansha): 後藤 知伸 鳥取大学, 工学研究科, 教授 (00260654)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 細菌 / べん毛 / 遊泳 / 方向転換 / 走化性 / ランダムウォーク

Outline of Final Research Achievements

In order to accurately predict the bacterial accumulation toward the attractant, the swimming movement of the single bacterial cell was measured in the presence of the concentration gradient of the attractant. A) It was found that the turning angle of Salmonella, which is a peritrichous bacterium, is smaller when approaching the attractant than when moving away. Analysis using a biased random walk model revealed that this difference in turning angle greatly contributes to the accumulation. B) By scanning the objective lens at high speed using a piezo element, three-dimensional measurement of the swimming trajectory of bacteria was performed, and the turning angle and swimming speed were accurately measured. C) We clarified the difference in the degree of accumulation in attractants due to the difference in swimming manner between monotrichous and peritrichous bacteria.

Free Research Field

生物流体力学

Academic Significance and Societal Importance of the Research Achievements

学術的意義：誘引物質に応答する細菌の遊泳方向転換角度変化については、これまでに予測されていたが、実際に観測したのは本研究が初めてである。またこの変化が集積現象に大きく影響することから、国内外の細菌走化性の研究における大きな進歩であると言える。
社会的意義：細菌や誘引物質の種類による集積度合の差異が定量化できることで、混合された細菌群から目的の細菌を分離するなど、細菌群をコントロールする実用化への道が開ける。また自然界に見られるバイオフィルムの理解にもつながると言える。