Abstract：
An anaerobic, mesophilic, syntrophic, archaeon strain MK-D1T, was isolated as a pure co-culture with Methanogenium sp. strain MK-MG from deep-sea methane seep sediment. This organism is, to our knowledge, the first cultured representative of \'Asgard\' archaea, an archaeal group closely related to eukaryotes. Here, we describe the detailed physiology and phylogeny of MK-D1T and propose Promethearchaeum syntrophicum gen. nov., sp. nov. to accommodate this strain. Cells were non-motile, small cocci, approximately 300-750 nm in diameter and produced membrane vesicles, chains of blebs and membrane-based protrusions. MK-D1T grew at 4-30 °C with optimum growth at 20 °C. The strain grew chemoorganotrophically with amino acids, peptides and yeast extract with obligate dependence on syntrophy with H2-/formate-utilizing organisms. MK-D1T showed the fastest growth and highest maximum cell yield when grown with yeast extract as the substrate: approximately 3 months to full growth, reaching up to 6.7×106 16S rRNA gene copies ml-1. MK-D1T had a circular 4.32 Mb chromosome with a DNA G+C content of 31.1 mol%. The results of phylogenetic analyses of the 16S rRNA gene and conserved marker proteins indicated that the strain is affiliated with \'Asgard\' archaea and more specifically DHVC1/DSAG/MBG-B and \'Lokiarchaeota\'/\'Lokiarchaeia\'. On the basis of the results of 16S rRNA gene sequence analysis, the most closely related isolated relatives were Infirmifilum lucidum 3507LTT (76.09 %) and Methanothermobacter tenebrarum RMAST (77.45 %) and the closest relative in enrichment culture was Candidatus \'Lokiarchaeum ossiferum\' (95.39 %). The type strain of the type species is MK-D1T (JCM 39240T and JAMSTEC no. 115508). We propose the associated family, order, class, phylum, and kingdom as Promethearchaeaceae fam. nov., Promethearchaeales ord. nov., Promethearchaeia class. nov., Promethearchaeota phyl. nov., and Promethearchaeati regn. nov., respectively. These are in accordance with ICNP Rules 8 and 22 for nomenclature, Rule 30(3)(b) for validation and maintenance of the type strain, and Rule 31a for description as a member of an unambiguous syntrophic association.
摘要：
厌氧菌,嗜温,互助性,古细菌菌株MK-D1T，被分离为与产甲烷的纯共培养物。来自深海甲烷渗漏沉积物的MK-MG菌株。这种有机体是，根据我们的知识，阿斯加德古细菌的第一个培养代表，一个与真核生物密切相关的古细菌群。这里,我们描述了MK-D1T的详细生理和系统发育，并提出了原生态古菌。11月。,sp.11月。来适应这种压力。细胞不运动，小球菌,直径约300-750nm，并产生膜囊泡，气泡和膜基突起的链。MK-D1T在4-30°C生长，在20°C最佳生长。该菌株与氨基酸在化学器官上生长，肽和酵母提取物对与利用H2/甲酸的生物的共生具有专一性依赖性。MK-D1T显示出最快的生长和最高的最大细胞产量时，以酵母提取物为底物：大约3个月到完全生长，达到6.7×10616SrRNA基因拷贝ml-1。MK-D1T具有环状4.32Mb染色体,DNAG+C含量为31.1mol%。16SrRNA基因和保守标记蛋白的系统发育分析结果表明，该菌株与\'Asgard\'古细菌有关，更具体地说与DHVC1/DSAG/MBG-B和\'Lokiarcheota\'/\'Lokiarchaeia\'有关。依据16SrRNA基因序列剖析成果，最密切相关的分离亲属是绿柱石3507LTT(76.09%)和蛇骨甲烷热杆菌RMAST(77.45%)，富集培养中最接近的亲属是念珠菌(95.39%)。类型物种的类型菌株是MK-D1T（JCM39240T和JAMSTEC号。115508).我们提议相关家庭，订单,类,门,和王国如普罗米修斯考古科法姆。11月。,普罗米修斯古细菌。11月。,Promethearchaeia类。11月。,Promethearchaeotaphyl.11月。,和普罗米修斯考古遗址。11月。,分别。这些符合ICNP命名规则8和22，规则30(3)(B)，用于验证和维护类型应变，和规则31a，用于描述为明确的融合协会的成员。
