Peduzzi Sandro, Welsh Allana, Demarta Antonella, Decristophoris Paola, Peduzzi Raffaele, Hahn Dittmar, Tonolla Mauro
Alpine Biology Center Foundation, Piora, CH-6777 Quinto, Switzerland.
Cantonal Institute of Microbiology, Microbial Ecology Laboratory, Microbiology Unit, Plant Biology Department, University of Geneva, Via Mirasole 22A, CH-6500 Bellinzona, Switzerland.
Int J Syst Evol Microbiol. 2011 Jul;61(Pt 7):1682-1687. doi: 10.1099/ijs.0.010397-0. Epub 2010 Aug 20.
Two isolates, designated CadH11(T) and Cad448(T), representing uncultured purple sulfur bacterial populations H and 448, respectively, in the chemocline of Lake Cadagno, a crenogenic meromictic lake in Switzerland, were obtained using enrichment and isolation conditions that resembled those used for cultured members of the genus Thiocystis. Phenotypic, genotypic and phylogenetic analyses of these isolates confirmed their assignment to the genus Thiocystis. However, 16S rRNA gene sequence similarities of 98.2 % between CadH11(T) and Cad448(T), and similarities of 97.7 and 98.5 %, respectively, with their closest cultured relative Thiocystis gelatinosa DSM 215(T), as well as differences in DNA G+C content and carbon source utilization suggested that the isolates belonged to two distinct species. DNA-DNA hybridization of CadH11(T) and Cad448(T) with T. gelatinosa DSM 215(T) showed relatedness values of 46.4 and 60.8 %, respectively; the relatedness value between CadH11(T) and Cad448(T) was 59.2 %. Based on this evidence, strains CadH11(T) and Cad448(T) represent two novel species within the genus Thiocystis, for which the names Thiocystis chemoclinalis sp. nov. and Thiocystis cadagnonensis sp. nov. are proposed, respectively. The type strains of T. chemoclinalis sp. nov. and T. cadagnonensis sp. nov. are CadH11(T) ( = JCM 15112(T) = KCTC 5954(T)) and Cad448(T) ( = JCM 15111(T) = KCTC 15001(T)), respectively.
从瑞士一个因泉水补给而产生分层的半混合湖卡达尼奥湖的化学分层带中，分别获得了代表未培养紫色硫细菌群体H和448的两个菌株，命名为CadH11(T)和Cad448(T)。所采用的富集和分离条件类似于用于培养硫囊菌属成员的条件。对这些菌株进行的表型、基因型和系统发育分析证实它们属于硫囊菌属。然而，CadH11(T)和Cad448(T)之间的16S rRNA基因序列相似性为98.2%，与它们最接近的已培养亲缘种凝胶硫囊菌DSM 215(T)的相似性分别为97.7%和98.5%，以及DNA G+C含量和碳源利用方面的差异表明这些菌株属于两个不同的物种。CadH11(T)和Cad448(T)与凝胶硫囊菌DSM 215(T)的DNA-DNA杂交显示相关性值分别为46.4%和60.8%；CadH11(T)和Cad448(T)之间的相关性值为59.2%。基于这些证据，菌株CadH11(T)和Cad448(T)代表硫囊菌属内的两个新物种，分别提议将其命名为化学分层硫囊菌（Thiocystis chemoclinalis sp. nov.）和卡达尼奥硫囊菌（Thiocystis cadagnonensis sp. nov.）。化学分层硫囊菌（Thiocystis chemoclinalis sp. nov.）和卡达尼奥硫囊菌（Thiocystis cadagnonensis sp. nov.）的模式菌株分别为CadH11(T)（=JCM 15112(T)=KCTC 5954(T)）和Cad448(T)（=JCM 15111(T)=KCTC 15001(T)）。
