Terrestrial Ecology Group, Institute of Zoology, University of Cologne, Cologne, Germany.
Front Cell Infect Microbiol. 2021 Mar 8;11:642216. doi: 10.3389/fcimb.2021.642216. eCollection 2021.
Legionellales-infected water is a frequent cause of local outbreaks of Legionnaires' disease and Pontiac fever. Decontaminations are difficult because Legionellales reproduce in eukaryotic microorganisms (protists). Most often, Legionellales have been isolated from amoebae; however, the culture-based sampling methods are taxonomically biased. Sequencing studies show that amoebae in the cercozoan class Thecofilosea are dominant in soils and wastewater treatment plants, prompting us to screen their capability to serve as potential hosts of endosymbiotic bacteria. Environmental isolates of Thecofilosea contained a surprising richness of endosymbiotic Legionellales, including . Considering the widespread dispersal of Legionellales in apparently unrelated amoeboid protist taxa, it appears that the morphotype and not the evolutionary origin of amoebae determines their suitability as hosts for Legionellales. We further provide a protocol for gnotobiotic cultivation of Legionellales and their respective hosts, facilitating future genomic and transcriptomic research of host-symbiont relationships.
军团菌感染的水是地方性军团病和庞蒂亚克热暴发的常见原因。由于军团菌在真核微生物（原生动物）中繁殖，因此去污非常困难。军团菌最常从变形虫中分离出来；然而，基于培养的采样方法存在分类偏见。测序研究表明，在有孔虫类 Cercozoa 目中的阿米巴虫在土壤和废水处理厂中占优势，促使我们筛选它们作为内共生细菌潜在宿主的能力。Thecofilosea 的环境分离物中含有丰富的内共生军团菌，包括. 鉴于军团菌在显然没有亲缘关系的变形虫原生动物分类群中广泛传播，似乎是阿米巴虫的形态而不是进化起源决定了它们作为军团菌宿主的适宜性。我们进一步提供了一种用于共生培养军团菌及其各自宿主的方案，为宿主-共生体关系的未来基因组和转录组研究提供了便利。
