Fervidicoccus fontis gen. nov., sp. nov., an anaerobic, thermophilic crenarchaeote from terrestrial hot springs, and proposal of Fervidicoccaceae fam. nov. and Fervidicoccales ord. nov.

Abstract

Two novel thermophilic and slightly acidophilic strains, Kam940T and Kam1507b, which shared 99 % 16S rRNA gene sequence identity, were isolated from terrestrial hot springs of the Uzon caldera on the Kamchatka peninsula. Cells of both strains were non-motile, regular cocci. Growth was observed between 55 and 85 °C, with an optimum at 65–70 °C (doubling time, 6.1 h), and at pH 4.5–7.5, with optimum growth at pH 5.5–6.0. The isolates were strictly anaerobic organotrophs and grew on a narrow spectrum of energy-rich substrates, such as beef extract, gelatin, peptone, pyruvate, sucrose and yeast extract, with yields above 107 cells ml−1. Sulfate, sulfite, thiosulfate and nitrate added as potential electron acceptors did not stimulate growth when tested with peptone. H2 at 100 % in the gas phase inhibited growth on peptone. Glycerol dibiphytanyl glycerol tetraethers (GDGTs) with zero to four cyclopentyl rings were present in the lipid fraction of isolate Kam940T. The G+C content of the genomic DNA of strain Kam940T was 37 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolates were archaea of the phylum Crenarchaeota, only distantly related to the cultured members of the class Thermoprotei (no more than 89 % identity), and formed an independent lineage adjacent to the orders Desulfurococcales and Acidilobales and clustering only with uncultured clones from hot springs of Yellowstone National Park and Iceland as the closest relatives. On the basis of their phylogenetic position and novel phenotypic features, isolates Kam940T and Kam1507b are proposed to be assigned to a new genus and species, Fervidicoccus fontis gen. nov., sp. nov. The type strain of Fervidicoccus fontis is strain Kam940T (=DSM 19380T =VKM B-2539T). The phylogenetic data as well as phenotypic properties suggest that the novel crenarchaeotes form the basis of a new family, Fervidicoccaceae fam. nov., and order, Fervidicoccales ord. nov., within the class Thermoprotei.

Temperature and pH control on lipid composition of silica sinters from diverse hot springs in the Taupo Volcanic Zone, New Zealand

“…Hopanoids were also detected in a range of stereoisomers, albeit in subordinate abundance; the source of these compounds is unclear. The predominance of GDGTs bearing 0–4 cyclopentane rings and the conditions at Rotokawa spring are also consistent with a thermoacidophilic Thermoprotei source (Perevalova et al 2010 ).…”

Archaea in Biogeochemical Cycles

“…Crenarchaeota contain only one taxonomic class (i.e., Thermoprotei ) and five taxonomic orders (i.e., Acidilobales, Desulfurococcales, Fervidicoccales, Sulfolobales, and Thermoproteales), two of which (Acidilobales and Fervidicoccales) were discovered only recently (100,106). All crenarchaeotes have been found in hot environments such as acidic terrestrial hot springs and submarine hydrothermal vents, as well as smoldering refuse piles (61).…”

Extending the Conserved Phylogenetic Core of Archaea Disentangles the Evolution of the Third Domain of Life

“…For instance, several lineages of uncultured fast-evolving nanosized archaea (Nanoarchaeota, ARMAN, and Nanohaloarchaea) have been discovered in very different environments (Huber et al 2002;Baker et al 2006;Narasingarao et al 2012), but their phylogenetic position remains highly debated (Brochier-Armanet et al 2011;Rinke et al 2013;Raymann et al 2014). In addition, several other newly proposed lineages are disputed, such as the Acidilobales and the Fervidicoccales within Crenarchaeota (Prokofeva et al 2009;Mardanov et al 2010;Perevalova et al 2010) and the candidate phylum "Aigarchaeota" (Nunoura et al 2011), (see Brochier-Armanet et al 2011, and references therein). Finally, a number of other important issues remain open, such as the relationships among the archaeal phyla (Euryarchaeota, Crenarchaeota, Thaumarchaeota [including 'Aigarchaeota'] and Korarchaeota) and thus the location of the root of Archaea, the monophyly of some orders such as the Desulfurococcales, and the relationships among methanogens Class I lineages, and among the methanogens Class II and the Halobacteriales.…”