Thiocystis chemoclinalis sp. nov. and Thiocystis cadagnonensis sp. nov., motile purple sulfur bacteria isolated from the chemocline of a meromictic lake.
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.
Peduzzi
Sandro
S
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.
Welsh
Allana
A
Department of Biology, Texas State University, 601 University Drive, San Marcos, TX 78666, USA.
Demarta
Antonella
A
Cantonal Institute of Microbiology, Microbial Ecology Laboratory, Microbiology Unit, Plant Biology Department, University of Geneva, Via Mirasole 22A, CH-6500 Bellinzona, Switzerland.
Decristophoris
Paola
P
Cantonal Institute of Microbiology, Microbial Ecology Laboratory, Microbiology Unit, Plant Biology Department, University of Geneva, Via Mirasole 22A, CH-6500 Bellinzona, Switzerland.
Peduzzi
Raffaele
R
Alpine Biology Center Foundation, Piora, CH-6777 Quinto, Switzerland.
Hahn
Dittmar
D
Department of Biology, Texas State University, 601 University Drive, San Marcos, TX 78666, USA.
Tonolla
Mauro
M
Cantonal Institute of Microbiology, Microbial Ecology Laboratory, Microbiology Unit, Plant Biology Department, University of Geneva, Via Mirasole 22A, CH-6500 Bellinzona, Switzerland.
D015373:Bacterial Typing Techniques; D001482:Base Composition; D002841:Chromatiaceae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000235:genetics; D060106:Lakes / Q000382:microbiology*; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010802:Phylogeny; D010860:Pigments, Biological / Q000737:chemistry; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013557:Switzerland; D014871:Water Microbiology
D004269:DNA, Bacterial; D010860:Pigments, Biological; D012336:RNA, Ribosomal, 16S