共同研究報告書


研究区分 一般研究

研究課題

 Characterizing microbial iron metabolism
新規・継続の別 新規
研究代表者／所属 海洋研究開発機構
研究代表者／職名 博士研究員
研究代表者／氏名 Jackson Makoto TSUJI

研究分担者／氏名／所属／職名
　
氏　　名
所　　属
職　　名

1

 高野淑識 海洋研究開発機構 センター長代理

2

 塚谷祐介 海洋研究開発機構 副主任研究員

3

 渡邉友浩 北大低温研

4

 福井学 北大低温研

5

 田中亮一 北大低温研

6

 高林厚史 北大低温研

研究目的 Iron is a key nutrient for life on the modern planet and was likely crucial for global nutrient cycling on early Earth. However， microbial iron metabolism remains poorly understood. Here we characterized novel iron-cycling bacteria through laboratory cultivation and study of anoxic ecosystems.
　　
研究内容・成果 During two visits to the ILTS (one short， one extended) by the applicant， we characterized "Candidatus Chlorohelix allophototropha"， a highly novel phototrophic bacterium that performs light-driven iron oxidation based on preliminary data. We confirmed the presence of bacteriochlorophyll a in the culture to validate the bacterium’s phototrophic metabolism (included in Tsuji et al.， 2024). We also used cutting-edge biochemical techniques with this bacterium to obtain a large protein-pigment complex， which may be the photosynthetic reaction center complex， that we will further analyze in FY2024. To better understand the iron metabolism of "Ca. Chx. allophototropha"， we performed dilution-to-extinction experiments to isolate the iron-reducing partner strain in the culture. Final isolation experiments are now running at the ILTS. Lastly， we discussed field data from two anoxic ecosystems， Lake Harutori and Oze National Park， and presented work on novel microbial communities that likely participate in iron， sulfur， and/or methane cycling in these systems (see below). Our combined cultivation and field research clarifies the physiology and ecology of iron-cycling bacteria on Earth.
　　
成果となる論文・学会発表等 [1] J. M. Tsuji， N. A. Shaw， … T. Watanabe， M. Fukui， et al. Nature. Online ahead of print. 2024. https://doi.org/10.1038/s41586-024-07180-y
[2] J. M. Tsuji. Ecology of Snow and Ice Meeting， ILTS， Sapporo， Japan. Contributed oral presentation. December 22nd， 2023.
[3] J. M. Tsuji， T. Watanabe， M. Fukui. Japanese Society of Limnology (JSLIM) 87th Annual Meeting， Oita， Japan. Contributed oral presentation. October 15th， 2023.