Characterization of "Candidatus Nebulobacter yamunensis" from the cytoplasm of Euplotes aediculatus (Ciliophora, Spirotrichea) and emended description of the family Francisellaceae
Characterization of "Candidatus Nebulobacter yamunensis" from the cytoplasm of Euplotes aediculatus (Ciliophora, Spirotrichea) and emended description of the family Francisellaceae
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DOI：
10.1016/j.syapm.2012.07.003
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发表时间：
2012-10-01
影响因子：
3.4
通讯作者：
Petroni, Giulio
中科院分区：
文献类型：
--
作者：
Boscaro, Vittorio;Vannini, Claudia;Petroni, Giulio
在过去的几十年里，由于不可培养细菌的表征方法的发展，我们对纤毛虫内共生体的发生和多样性的了解大大扩大了。在不同纤毛虫种类的细胞质中检测到与立克次体和弗朗西斯菌等人类病原体相关的共生体。在目前的工作中，我们在丰富的原核生物群落中鉴定了一种新的Francisella-related细菌，该群落由adiculatus Euplotes（纤毛虫目，螺旋体虫目）组成。根据“全周期rRNA方法”，我们获得了该细菌几乎完整的16S rRNA基因序列，并开发了用于诊断荧光原位杂交的探针。在宿主外培养内共生体的尝试失败了。我们将这种新生物分类在一个新的分类单元中，我们建议将其命名为“Candidatus Nebulobacter yamunensis”。为了研究其进化关系，我们还对Gammaproteobacteria纲和thiiotrichales纲进行了系统发育分析，其中包括单属Francisellaceae。我们发现了一个新的单系分类群的建立，包括Francisella种，其他生物目前的incertae sedis和Candidatus Nebulobacter yamunensis。这些生物形成了一个分支，共享一个特征序列，而在其他硫代三卤细菌中不存在。此外，它们大多在真核生物体内形成细胞内生命周期。我们修改了Francisellaceae科的原始描述，以便涵盖所描述的分支的所有成员。(C) 2012 Elsevier GmbH版权所有。
Our knowledge of ciliate endosymbionts occurrence and diversity greatly expanded in the last decades, due to the development of characterization methods for uncultivable bacteria. Symbionts related to human pathogens such as rickettsiae and francisellae have been detected inside the cytoplasm of different ciliate species. In the present work, we have characterized a novel Francisella-related bacterium inside the rich prokaryotic community harbored by a population of Euplotes aediculatus (Ciliophora, Spirotrichea). Following the "Full-Cycle rRNA Approach" we obtained the almost full-length 16S rRNA gene sequence of this bacterium, and developed probes for diagnostic fluorescence in situ hybridizations. Attempts to culture the endosymbiont outside of its host failed. We classified this novel organism in a new taxon for which we propose the name "Candidatus Nebulobacter yamunensis". In order to investigate its evolutionary relationships, we have also performed phylogenetic analyses on the class Gammaproteobacteria and the order Thiotrichales, which include the monogeneric family Francisellaceae. We found highly supported evidences for the establishment of a new monophyletic taxon including Francisella species, other organisms currently incertae sedis, and "Candidatus Nebulobacter yamunensis". These organisms form a clade sharing a signature sequence not present in other Thiotrichales bacteria. Moreover, most of them have developed an intracellular life cycle inside eukaryotic organisms. We emended the original description of family Francisellaceae in order to encompass all members of the described clade. (C) 2012 Elsevier GmbH. All rights reserved.