Most microorganisms from deep terrestrial subsurface remain yet uncultured. Recent achievements in recovery of metagenome-assembled genomes (MAG) provide clues for improving cultivation via metabolic reconstructions and other genomic characteristics. Here we report the isolation in pure culture of a thermophilic spirochete with the use of MAGs binned from metagenomes of the deep (>2 km) aquifers broached by two artesian boreholes in Western Siberia. The organism constitutes a minor share in the aquifer microbial community and could not be cultivated by traditional techniques. The obtained two pure culture isolates along with three bacteria identified by MAGs represent a novel family-level lineage in the order Brevinematales. Based on genomic and phenotypic characteristics the novel spirochete is proposed to be classified as Longinema margulisiae gen. nov., sp. nov. within a novel family, Longinemaceae fam. nov. Both cultivated strains, NS^T and N5R, are anaerobic hemoorganoheterotrophes growing by fermentation of starch and a few sugars. They can form recalcitrant round bodies under unfavourable growth conditions, which survive up to 15 min at 95°C and can revert to the original helical cells. We suggest that the round bodies may facilitate global distribution of this lineage, detected from molecular signaturesand colonization of subsurface environments.

中文翻译：

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基于宏基因组组装基因组的靶向分离揭示了来自深部生物圈的一组系统发育不同的嗜热螺旋体

大多数来自地表深处的微生物仍未培养。最近在恢复宏基因组组装基因组 (MAG) 方面的成就为通过代谢重建和其他基因组特征改善培养提供了线索。在这里，我们报告了嗜热螺旋体的纯培养物的分离，该方法使用从西西伯利亚两个自流钻孔拉削的深层（> 2 公里）含水层的宏基因组中分离出来的 MAGs。该生物在含水层微生物群落中只占很小的份额，不能通过传统技术培养。获得的两种纯培养分离物以及通过 MAG 鉴定的三种细菌代表了Brevinematales 目中的新家族级谱系. 基于基因组和表型特征，新螺旋体被提议归类为Longinema margulisiae gen。十一月，sp。十一月 在一个新的家族中，浪琴科家族。十一月 培养的菌株 NS ^T和 N5R 都是通过淀粉和少量糖发酵生长的厌氧血有机异养菌。它们可以在不利的生长条件下形成顽固的圆形体，在 95°C 下可以存活长达 15 分钟，并且可以恢复到原来的螺旋细胞。我们认为圆形物体可能有助于该谱系的全球分布，从分子特征和地下环境的定殖中检测到。