Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Ibaraki 305-0074, Japan.
Graduate School of Life Sciences, Toyo University, Oura, Gunma 374-0193, Japan.
Int J Syst Evol Microbiol. 2022 Aug;72(8). doi: 10.1099/ijsem.0.005489.
A co-culture of a novel thermoacidophilic, obligate symbiotic archaeon, designated as strain MJ1, with its specific host archaeon strain MJ1HA was obtained from a terrestrial hot spring in Japan. Strain MJ1 grew in the co-culture under aerobic conditions. Coccoid cells of strain MJ1 were 200-500 nm in diameter, and attached to the MJ1HA cells in the co-culture. The ranges and optima of the growth temperature and pH of strain MJ1 in the co-culture were 60-75 °C (optimum, 65-70 °C) and pH 1.0-4.0 (optimum, pH 2.5), respectively. Core lipids of dialkyl glycerol tetraethers (GDGT)-3 and GDGT-4 were highly abundant in MJ1 cells concentrated from the co-culture. Strain MJ1 has a small genome (0.67 Mbp) lacking genes for biosynthesis of essential biomolecules, such as nucleotides, lipids and ATP. The genomic DNA G+C content was 24.9 mol%. The 16S rRNA gene sequence of strain MJ1 was most closely related to that of the cultivated species, ' strain N7A (85.8 % similarity). Based on phylogenetic and physiological characteristics, we propose the name gen. nov., sp. nov. to accommodate the strain MJ1 (=JCM 33616=DSM 111728). In addition, we propose the names fam. nov., ord. nov., and class. nov. to accommodate the novel genus.
从日本的一处陆地温泉中获得了一种新型嗜热嗜酸、专性共生古菌菌株 MJ1 及其特定宿主古菌菌株 MJ1HA 的共培养物。菌株 MJ1 在共培养物中于需氧条件下生长。菌株 MJ1 的球形细胞直径为 200-500nm，并附着在共培养物中的 MJ1HA 细胞上。在共培养物中，菌株 MJ1 的生长温度和 pH 的范围和最佳值分别为 60-75°C（最佳温度为 65-70°C）和 pH 1.0-4.0（最佳 pH 值为 2.5）。从共培养物中浓缩的 MJ1 细胞中富含二烷基甘油四醚（GDGT）-3 和 GDGT-4 的核心脂质。菌株 MJ1 的基因组较小（0.67 Mbp），缺乏核苷酸、脂质和 ATP 等必需生物分子的生物合成基因。基因组 DNA G+C 含量为 24.9mol%。菌株 MJ1 的 16S rRNA 基因序列与已培养的物种“N7A 株”最为相似（相似度为 85.8%）。基于系统发育和生理特性，我们建议将菌株 MJ1 命名为新属、新种，以容纳该菌株（=JCM 33616=DSM 111728）。此外，我们建议使用新科、新目和新纲来容纳这个新的属。
