Aquificae

Aquificae
Scientific classification
Domain:	Bacteria
Phylum:	Aquificae
Class:	Aquificae Reysenbach 2002
Order:	Aquificales Reysenbach 2002
Families
Thermosulfidibacter Nunoura et al. 2008 Aquificaceae Reysenbach 2002 Aquifex Huber and Stetter 1992 Hydrogenivirga Nakagawa et al. 2004 Hydrogenobacter Kawasumi et al. 1984 Hydrogenobaculum Stöhr et al. 2001 Thermocrinis Huber et al. 1999 Desulfurobacteriaceae L'Haridon et al. 2006 Balnearium Takai et al. 2003 Desulfurobacterium L'Haridon et al. 1998 emend. L'Haridon et al. 2006 Phorcysium ♠ Vetriani 2011 Thermovibrio Huber et al. 2002 Hydrogenothermaceae Eder and Huber 2003 Hydrogenothermus Stöhr et al. 2001 Persephonella Götz et al. 2002 Sulfurihydrogenibium Takai et al. 2003 emend. O'Neill et al. 2008 Venenivibrio Hetzer et al. 2008

The Aquificae phylum is a diverse collection of bacteria that live in harsh environmental settings. They have been found in hot springs, sulfur pools, and thermal ocean vents. Members of the genus Aquifex, for example, are productive in water between 85 to 95 °C. They are the dominant members of most terrestrial neutral to alkaline hot springs above 60 degrees Celsius. They are autotrophs, and are the primary carbon fixers in these environments. They are true bacteria (domain bacteria) as opposed to the other inhabitants of extreme environments, the Archaea.

Taxonomy

There is currently no consensus regarding the taxonomy of genera within Aquificae. One standard text claims that only the genera Aquifex, Calderobacterium, Hydrogenobacter, and Thermocrinis belong in the Aquificales order. Another claims that, in addition to genera within the Aquificaceae and Hydrogenothermaceae families, the following genera are incertae sedis (unclassified), but within Aquificae: Balnearium, Desulfurobacterium, EX-H1 group, and Thermovibrio.

Cavalier-Smith has postulated that Aquificae is part of the Proteobacteria.

Along with Thermotogae, members of Aquificae are thermophilic eubacteria.

Phylogeny

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI) and the phylogeny is based on 16S rRNA-based LTP release 106 by The All-Species Living Tree Project

Thermosulfidibacter takaii Nunoura et al. 2008   Desulfurobacteriaceae ?Phorcysium thermohydrogeniphilum ♠ Vetriani 2011 ?Desulfurobacterium crinifex ♠ Alain et al. 2003 Desulfurobacterium thermolithotrophum L'Haridon et al. 1998 Desulfurobacterium atlanticum L'Haridon et al. 2006 Desulfurobacterium pacificum L'Haridon et al. 2006 Thermovibrio ruber Huber et al. 2002 Balnearium lithotrophicum Takai et al. 2003 Thermovibrio ammonificans Vetriani et al. 2004 Thermovibrio guaymasensis L'Haridon et al. 2006   Hydrogenothermaceae   Persephonella P. guaymasensis Götz et al. 2002 P. hydrogeniphila Nakagawa et al. 2003 P. marina Götz et al. 2002 Venenivibrio stagnispumantis Hetzer et al. 2008 Hydrogenothermus marinus Stöhr et al. 2001   Sulfurihydrogenibium S. yellowstonense Nakagawa et al. 2005 S. azorense Aguiar et al. 2004 emend. Nakagawa et al. 2005 S. subterraneum Takai et al. 2003 emend. Nakagawa et al. 2005 S. kristjanssonii Flores et al. 2008 S. rodmanii O'Neill et al. 2008   Aquificaceae Hydrogenobaculum acidophilum (Shima and Suzuki 1993) Stöhr et al. 2001 Thermocrinis minervae Huber et al. 1999   Hydrogenobacter H. hydrogenophilus (Kryukov et al. 1984) Stöhr et al. 2001 H. thermophilus Kawasumi et al. 1984 Hydrogenobacter subterraneus Takai et al. 2001 ?Thermothrix azorensis Odintsova EV et al. (1996) Thermocrinis ruber Huber et al. 1999 Thermocrinis albus Eder and Huber 2002   Aquifex A. aeolicus ♠ Huber and Stetter 2001 A. pyrophilus Huber and Stetter 1992   Hydrogenivirga H. calditorris Nakagawa et al. 2004 H. okinawensis Nunoura et al. 2008

Note:
♠ Strain found at the National Center for Biotechnology Information (NCBI) but not listed in the List of Prokaryotic names with Standing in Nomenclature (LPSN)