DPANN archaea are an enigmatic superphylum that are difficult to isolate and culture in the laboratory due to their specific culture conditions and apparent ectosymbiotic lifestyle. Here we successfully isolated and cultivated a co-culture system of a novel Nanobdellota archaeon YN1 and its host Sulfurisphaera ohwakuensis YN1HA. We characterised the co-culture system by complementary methods, including metagenomics and metabolic pathway analysis, fluorescence microscopy, and high-resolution electron cryo-tomography (cryoET). We show that YN1 is deficient in essential metabolic processes and requires host resources to proliferate. CryoET imaging revealed an enormous attachment organelle present in the YN1 envelope that forms a direct interaction with the host cytoplasm, bridging the two cells. Together our results unravel the molecular and structural basis of ectosymbiotic relationship between YN1 and YNHA. This research broadens our understanding of DPANN biology and the versatile nature of their ectosymbiotic relationships.

中文翻译：

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大型附着细胞器介导纳米菌古菌 YN1 与其宿主之间的相互作用


DPANN古菌是一个神秘的总门，由于其特定的培养条件和明显的外共生生活方式，很难在实验室中分离和培养。在这里，我们成功分离并培养了一种新型纳米菌古菌YN1及其宿主Sulfurisphaera ohwakuensis YN1HA的共培养系统。我们通过补充方法对共培养系统进行了表征，包括宏基因组学和代谢途径分析、荧光显微镜和高分辨率电子冷冻断层扫描（cryoET）。我们发现 YN1 缺乏必要的代谢过程，并且需要宿主资源才能增殖。 CryoET 成像揭示了 YN1 包膜中存在巨大的附着细胞器，它与宿主细胞质形成直接相互作用，从而桥接两个细胞。我们的结果共同揭示了 YN1 和 YNHA 之间外共生关系的分子和结构基础。这项研究拓宽了我们对 DPANN 生物学及其外共生关系的多功能性的理解。