Phylogenetic diversity of intra-amoebal legionellae as revealed by 16S rRNA gene sequence comparison
Phylogenetic diversity of intra-amoebal legionellae as revealed by 16S rRNA gene sequence comparison
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DOI：
10.1099/13500872-142-12-3525
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发表时间：
1996-12-01
期刊：
影响因子：
--
通讯作者：
Harrison, TG
中科院分区：
文献类型：
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作者：
Birtles, RJ;Rowbotham, TJ;Harrison, TG
最近对军团菌属的所有39种及其相关生物进行了系统发育分析，建议将其命名为军团菌，以表示以前被认为是军团菌样阿米巴病原体(Legionella Lyticum)或军团菌样阿米巴病原体(Legionella-like amebal病原体)的细菌。为了研究这一新物种的系统发育完整性，我们测定了从不同环境来源分离的10个LLAP的16S rRNA基因序列。所有10个分离株都聚集在一个包含军团菌属所有其他成员的单系群中。10个分离物中有8个在该属内形成了一个单系亚群，该亚群还包括两个先前特征的赖氏乳杆菌菌株。这10个分离株中有4个与溶血链霉菌类型菌株有非常密切的亲缘关系(>；99%的序列相似性)。然而，尽管明显是军团菌群，其余两个LLAP菌株与Lytica或任何其他军团菌物种没有特定的进化关系(序列相似性为96%)，这两个分离株都位于军团菌簇辐射内各自相对根深蒂固的分支上，因此，LLAP不代表一个独特的物种，甚至不代表该属内的一个谱系，对更多分离株的研究可能会发现它们在进化上与其他目前公认的军团菌物种一样多样化。
Following a recent phylogenetic analysis of all 39 species of the genus Legionella and related organisms, the name Legionella lytica has been proposed for bacteria previously considered either as Sarcobium lyticum or as 'Legionella-like amoebal pathogens' (LLAPs). To investigate the phylogenetic integrity of this newly proposed species, we determined the 16S rRNA gene sequences of 10 LLAPs isolated from various environmental sources. All 10 isolates clustered within a monophyletic group containing all other members of the genus Legionella. Eight of the 10 isolates formed a monophyletic subgroup within the genus which also included the two previously characterized L. lytica strains. Four of these 10 isolates shared a specific and very close relationship with the L. lytica type strain (> 99% sequence similarity). However, although clearly legionellae, the remaining two LLAP strains bore no specific evolutionary relationship to either L. lytica or any other Legionella species (< 96% sequence similarity), Both isolates lay on their own relatively deep-rooted branches within the radiation of the Legionella cluster, LLAPs do not, therefore, represent a unique species or even a single line of descent within the genus, and investigation of more isolates may reveal them to be as evolutionarily diverse as the other presently recognized Legionella species.