Ignavibacterium album gen. nov., sp. nov., a moderately thermophilic anaerobic bacterium isolated from microbial mats at a terrestrial hot spring and proposal of Ignavibacteria classis nov., for a novel lineage at the periphery of green sulfur bacteria.
A moderately thermophilic chemoheterotrophic bacterium, strain Mat9-16(T), was isolated from microbial mats developed in hot spring water streams from Yumata, Nagano, Japan. Cells of strain Mat9-16(T) were strictly anaerobic, Gram-stain-negative, non-sporulating, non-motile and short to long rods (2.0-15.5 mum in length). Strain Mat9-16(T) grew fermentatively with optimum growth at 45 degrees C, pH 7.0-7.5 and 1 % NaCl (w/v). Phylogenetic analysis based on the 16S rRNA gene revealed that strain Mat9-16(T) was affiliated with an uncultivated lineage, and the nearest cultivated neighbours were green sulfur bacteria belonging to the class Chlorobea with 77-83 % sequence similarity. However, strain Mat9-16(T) could not grow phototrophically and did not possess light-harvesting structures, morphologically and genetically, such as the chlorosomes of green sulfur bacteria. On the basis of phenotypic features and phylogenetic position, a novel genus and species are proposed for strain Mat9-16(T), to be named Ignavibacterium album gen. nov., sp. nov. (=NBRC 101810(T) =DSM 19864(T)). We also propose to place the cultivated bacterial lineage accommodating the sole representative Mat9-16(T) in a novel class, Ignavibacteria classis nov. In addition, we present a formal description of the phylum-level taxon 'Chlorobi' as Chlorobi phyl. nov.
Iino
Takao
T
NITE Biological Resource Center (NBRC), National Institute of Technology and Evaluation (NITE), 2-5-8, Kazusakamatari, Kisarazu, Chiba 292-0818, Japan.
Mori
Koji
K
NITE Biological Resource Center (NBRC), National Institute of Technology and Evaluation (NITE), 2-5-8, Kazusakamatari, Kisarazu, Chiba 292-0818, Japan.
Uchino
Yoshihito
Y
NITE Biological Resource Center (NBRC), National Institute of Technology and Evaluation (NITE), 2-5-8, Kazusakamatari, Kisarazu, Chiba 292-0818, Japan.
Nakagawa
Tatsunori
T
NITE Biological Resource Center (NBRC), National Institute of Technology and Evaluation (NITE), 2-5-8, Kazusakamatari, Kisarazu, Chiba 292-0818, Japan.
Harayama
Shigeaki
S
NITE Biological Resource Center (NBRC), National Institute of Technology and Evaluation (NITE), 2-5-8, Kazusakamatari, Kisarazu, Chiba 292-0818, Japan.
Suzuki
Ken-Ichiro
KI
NITE Biological Resource Center (NBRC), National Institute of Technology and Evaluation (NITE), 2-5-8, Kazusakamatari, Kisarazu, Chiba 292-0818, Japan.
D001426:Bacterial Proteins / Q000235:genetics; D019414:Chlorobi / Q000145:classification; D004777:Environment; D005798:Genes, Bacterial; D006089:Gram-Negative Anaerobic Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000648:ultrastructure; D008854:Microscopy, Electron; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics
D001426:Bacterial Proteins; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S