共同研究報告書


研究区分 開拓型研究

研究課題

 気候変動下における彩雪現象の解明
新規・継続の別 開拓型（2年目/全3年）
研究代表者／所属 ベルリン応用科学大
研究代表者／職名 教授
研究代表者／氏名 寺島美亜

研究分担者／氏名／所属／職名
　
氏　　名
所　　属
職　　名

1

 Jackson Tsuji JAMSTEC 博士研究員

2

 梅澤和寛 静岡県立大 助教

3

 Rudolf Amann マックスプランク海洋微生物学研究所 教授

4

 福井学 北大低温研

5

 田中亮一 北大低温研

6

 渡邉友浩 北大低温研

研究目的 Colored snow caused by microorganisms in alpine and polar regions is a prominent phenomenon that impacts the ecosystem and its occurrence is not yet well-understood. The key to understanding the phenomenon of colored snow under climate change is to elucidate key microbial interactions. The objective of this study is to characterize the microbial communities in colored snow samples. Additionally， this project aims to isolate novel microbes for physiological characterization and to analyze the metagenome of colored snow communities to elucidate the key metabolic pathways in these environments.
　　
研究内容・成果 We obtained valuable algae-containing colored snow samples from Langhovde， Antarctica. The snow is colored green and numerous microalgal cells were confirmed via microscopy. These samples were analyzed by 18S rRNA and 16S rRNA amplicon sequencing， metagenome assembly analyses， and strain isolation. Through amplicon sequencing we identified that green algae were the dominant eukaryotes in the sample， with most species belong to the Chlorophyceae class， followed by the class Trebouxiophyceae. Aside from green algae， fungi in the division Basidiomycota and flagellates Heteromita were present. For the prokaryotes， Bacteroidia was the dominant class， followed by Gamma- and Alphaproteobacteria.
In the metagenome analysis， 30 metagenome-assembled genomes (MAGs) of prokaryotes were recovered and identified Gammaproteobacteria in the family of Burkholderiaceae to be particularly abundant. We also further created a gene catalog for the prokaryotic metagenome， which represents 10% of the metagenome data. Among the most abundant genes identified， genes for photosynthesis， photoreceptors and DNA damage response protein. Interestingly， several rhodopsin and rhodopsin-like genes were also identified in the metagenome. These results indicate an environment where microbes utilize light while managing the damaging effects of high light. These light-reactive proteins are likely to have significant roles in the microorganisms that are dominant in the colored snow by enabling the accurate detection， utilization， and adaptation to high light intensities in the snow surface environment.
To further characterize key bacterial species in the snow samples， we successfully isolated many colonies from the snow and identified these isolates through 16S Nanopore sequencing. Among these isolates， two strains are of particular interest as they are potentially novel species.
　　
成果となる論文・学会発表等 Kondo， K.， Ohtake， R.， Nakano， S.， Terashima， M.， Kojima， H.， Fukui， M.， Demura， M.， Kikukawa， T.， and Tsukamoto， T. (2024) Contribution of Proteorhodopsin to Light-Dependent Biological Responses in Hymenobacter nivis P3T Isolated from Red Snow in Antarctica. Biochemistry， 63(18): 2257–2265.