'Candidatus Planktophila limnetica', an actinobacterium representing one of the most numerically important taxa in freshwater bacterioplankton
'Candidatus Planktophila limnetica', an actinobacterium representing one of the most numerically important taxa in freshwater bacterioplankton
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DOI：
10.1099/ijs.0.010199-0
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发表时间：
2009-11-01
影响因子：
2.8
通讯作者：
Hahn, Martin W.
中科院分区：
文献类型：
--
作者：
Jezbera, Jan;Sharma, Adrian K.;Hahn, Martin W.
放线菌通常构成淡水系统中浮游细菌的大部分。培养独立的方法表明，所谓的ACL谱系经常代表最多的类群之间的组合淡水放线菌，甚至在总淡水浮游细菌。在位于各大洲和气候区的淡水栖息地中检测到了属于这种未耕种谱系的细菌，但在陆地或近海海洋系统中从未发现过。到目前为止，这一生态上重要的淡水放线菌谱系还没有一个公认的taxon.In这项研究中，我们建立了一个稳定的混合文化包含一个隶属于acl谱系的菌株在奥地利的淡水湖。培养物中菌株的比例可以通过操纵培养基组成增加一个以上的数量级，然而，所有随后将该菌株分离到纯培养物中的尝试均未成功。确定了该acl菌株的一些表型特征，并分析了其在放线菌中的分类地位。该生物的16S rRNA基因的系统发育分析显示，与栽培生物和公认的物种（89%的基因序列相似性与后者）的远亲关系。此外，该分析不支持将该菌株明确归属于放线菌门内任何公认的科。建议建立一个候选分类单元，'ApriodatusPlanktophilamnetica'来代表该菌株。
Actinobacteria often constitute a large fraction of the bacterioplankton in freshwater systems. Cultivation-independent methods have revealed that the so-called acl lineage frequently represents the most numerous taxon among assemblages of freshwater Actinobacteria and even among total freshwater bacterioplankton. Bacteria affiliated with this uncultivated lineage have been detected in freshwater habitats located in various continents and climatic zones but have never been found among terrestrial or offshore marine systems. So far, this ecologically important lineage of freshwater Actinobacteria is not represented by a recognized taxon. In this study, we established a stable mixed culture containing a strain affiliated with the acl lineage from a freshwater lake in Austria. The proportion of the strain in the culture could be increased by manipulation of the medium composition by more than one order of magnitude, however all subsequent attempts to isolate this strain into pure culture were unsuccessful. Some of the phenotypic traits of this acl strain were determined and its taxonomic position within the Actinobacteria was analysed. Phylogenetic analysis of this organism's 16S rRNA gene revealed a distant relationship with cultivated organisms and recognized species (89% gene sequence similarity with the latter). Furthermore, this analysis did not support a clear assignment of the strain to any of the recognized families within the phylum Actinobacteria. It is suggested that a candidate taxon, 'Candidatus Planktophila limnetica' is established to represent this strain.