[B-BG01] 地球惑星科学　生命圏フロンティア

[BBG01-P08] A Simple and Easy Way to Isolate Nanoarchaea from Acidic Hot Springs

*酒井 博之^1,2、面川 博美³、中村 光一³、布浦 拓郎⁴、黒沢 則夫^1,3 (1.創価大学 理工学部 共生創造理工学科、2.理化学研究所 バイオリソース研究センター 微生物材料開発室、3.創価大学大学院 理工学研究科 環境共生工学専攻、4.海洋研究開発機構 生命理工学センター)

キーワード：DPANN、Nanoarchaeota、好熱好酸性菌、Sulfolobales、陸上温泉

Nanoarchaea (the phylum Nanoarchaeota) are ectosymbiotic microorganisms belonging to the DPANN (an acronym for the phyla Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota, and Nanohaloarchaeota) superphylum. The most distinctive features of nanoarchaea are their tiny cells (< 0.5 μm in diameter) and small genomes (< 0.8 Mb in general). They are one of the smallest organisms having very limited metabolic capabilities (e.g., lack of the TCA cycle, glycolysis/gluconeogenesis, and electron transport chains). Elucidating their ecophysiology should contribute to understanding what is needed for the smallest life on the earth. So far, only five strains of nanoarchaea have been reported. All of them are obligate symbionts depending on a single host species. More than 20 years have passed since the first report of the cultivation of nanoarchaea by Huber et al. in 2002. However, their ecophysiology is still largely unknown. How do they interact with host species? What are their roles in natural environments? Do they affect the growth of host species negatively or positively (parasitic or mutualistic)? Are they important to the geochemical cycle on the earth? To answer these questions clearly, cultivation is the most robust tool even in this metagenomic era. Establishing easily cultivable strains must contribute to elucidating their ecophysiology. Recently, we have isolated four strains of nanoarchaea (with its host) from an acidic hot spring located in Kirishima, Japan. The procedures for the isolation of these nanoarchaea were quite simple. We used enrichment culture, 16S amplicon analysis, qPCR, and dilution to extinction method. In this poster, we will share how we isolated these four nanoarchaeal strains, as well as their physiological and genomic features.