Epsilonproteobacteria

Epsilonproteobacteria
Campylobacter
Scientific classification
Domain:	Bacteria
Phylum:	Proteobacteria
Class:	Epsilonproteobacteria
Orders
Nautiliales Nautiliaceae Caminibacter Lebetimonas Nautilia Nitratifractor Nitratiruptor Thioreductor Campylobacterales Hydrogenimonadaceae Hydrogenimonas Campylobacteraceae Candidatus Thioturbo' Arcobacter Campylobacter Sulfurospirillum Helicobacteraceae Helicobacter Sulfuricurvum Sulfurimonas Sulfurovum Thiovulum Wolinella

Epsilonproteobacteria are a class of Proteobacteria. All species of this class are, like all Proteobacteria, Gram-negative.

The Epsilonproteobacteria consist of few known genera, mainly the curved to spirilloid Wolinella spp., Helicobacter spp., and Campylobacter spp. Most of the known species inhabit the digestive tracts of animals and serve as symbionts (Wolinella spp. in cattle) or pathogens (Helicobacter spp. in the stomach, Campylobacter spp. in the duodenum).

Numerous environmental sequences and isolates of Epsilonproteobacteria have also been recovered from hydrothermal vents and cold seep habitats. Examples of isolates include Sulfurimonas autotrophica, Sulfurimonas paralvinellae,Sulfurovum lithotrophicum and Nautilia profundicola. A member of the class Epsilonproteobacteria occurs as an endosymbiont in the large gills of the deepwater sea snail Alviniconcha hessleri.

The Epsilonproteobacteria found at deep-sea hydrothermal vents characteristically exhibit chemolithotrophy, meeting their energy needs by oxidizing reduced sulfur, formate, or hydrogen coupled to the reduction of nitrate or oxygen. Autotrophic Epsilonproteobacteria use the reverse Krebs cycle to fix carbon dioxide into biomass, a pathway originally thought to be of little environmental significance. The oxygen sensitivity of this pathway is consistent with their microaerophilic or anaerobic niche in these environments, and their likely evolution in the Mesoproterozoic oceans, which are thought to have been sulfidic with low levels of oxygen available from cyanobacterial photosynthesis.

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

Nautiliaceae Thioreductor micantisoli Nakagawa et al.2005 Caminibacter Alain et al.2002 Lebetimonas acidiphila Takai et al.2005 Nautilia Miroshnichenko et al.2002 Nitratiruptor tergarcus Nakagawa et al.2   Campylobacterales Hydrogenimonas thermophila Takai et al.2004 ?Sulfuricurvum kujiense Kodama and Watanabe 2004 ?Thiovulum majus ♪ Hinze 1913 Nitratifractor salsuginis Nakagawa et al.2005 Sulfurovum lithotrophicum Inagaki et al.2004 Sulfurimonas Inagaki et al.2003 emend. Takai et al.2006   Helicobacteraceae Wolinella Tanner et al.1981 Helicobacter Goodwin et al.1989 emend. Vandamme et al.1991   Campylobacteraceae ?Candidatus Thioturbo danicus Muyzer et al. 2005 Arcobacter Vandamme et al.1991 emend. Vandamme et al.1992 Sulfurospirillum Schumacher et al.1993 emend. Luijten et al.2003 Campylobacter Sebald and Véron 1963 emend. Vandamme et al.2010

Notes:

• Prokaryotes where no pure (axenic) cultures are isolated or available, i.e. not cultivated or can not be sustained in culture for more than a few serial passages

External links

• Epsilonproteobacteria at the US National Library of Medicine Medical Subject Headings (MeSH)