Campylobacterota are a phylum of

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

. All

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of this phylum are

Gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall ...

. The Campylobacterota consist of few known genera, mainly the curved to spirilloid ''

Wolinella The genus ''Wolinella'' is a member of the Campylobacterales order of Bacteria. The order Campylobacterales includes human pathogens such as ''Helicobacter pylori'' and ''Campylobacter jejuni''. Strains The only publicly available strain of ''Wo ...

'' spp., ''

Helicobacter ''Helicobacter'' is a genus of Gram-negative bacteria possessing a characteristic helical shape. They were initially considered to be members of the genus ''Campylobacter'', but in 1989, Goodwin ''et al.'' published sufficient reasons to justif ...

'' spp., and '' Campylobacter'' spp. Most of the known species inhabit the digestive tracts of animals and serve as symbionts (''Wolinella'' spp. in

cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult mal ...

) or

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

s (''Helicobacter'' spp. in the stomach, ''Campylobacter'' spp. in the duodenum). Many Campylobacterota are motile with flagella. Numerous environmental sequences and isolates of Campylobacterota have also been recovered from

hydrothermal vent A hydrothermal vent is a fissure on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hotspot ...

s and

cold seep A cold seep (sometimes called a cold vent) is an area of the ocean floor where hydrogen sulfide, methane and other hydrocarbon-rich fluid seepage occurs, often in the form of a brine pool. ''Cold'' does not mean that the temperature of the see ...

habitats. Examples of isolates include ''

Sulfurimonas Sulfurimonas is a bacterial genus within the class of Campylobacterota, known for reducing nitrate, oxidizing both sulfur and hydrogen, and containing Group IV hydrogenases. This genus consists of four species: ''Sulfurimonas autorophica'', ''Sul ...

autotrophica'', ''

paralvinellae'', ''

Sulfurovum ''Sulfurovum'' is a genus within the ''Campylobacterota Campylobacterota are a phylum of bacteria. All species of this phylum are Gram-negative. The Campylobacterota consist of few known genera, mainly the curved to spirilloid ''Wolinella'' s ...

lithotrophicum'' and ''

Nautilia profundicola ''Nautilia profundicola'' is a Gram-negative chemolithoautotrophic bacterium found around hydrothermal vents in the deep ocean. It was first discovered in 1999 on the East Pacific Rise at depth of , on the surface of the polychaete worm ''Alvin ...

''. A member of the phylum Campylobacterota occurs as an

endosymbiont An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within" ...

in the large

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

s of the deepwater sea snail ''

Alviniconcha hessleri ''Alviniconcha'' is a genus of deep water sea snails, marine (ocean), marine gastropod mollusks in the family (biology), family Provannidae.Bouchet, P. (2013). Alviniconcha Okutani & Ohta, 1988. Accessed through: World Register of Marine Species ...

''. The Campylobacterota 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 Campylobacterota 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 The Mesoproterozoic Era is a geologic era that occurred from . The Mesoproterozoic was the first era of Earth's history for which a fairly definitive geological record survives. Continents existed during the preceding era (the Paleoproterozoic), ...

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 List of Prokaryotic names with Standing in Nomenclature (LPSN) is an online database that maintains information on the naming and taxonomy of prokaryotes, following the taxonomy requirements and rulings of the International Code of Nomenclature ...

(LPSN) and

National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The ...

(NCBI) and the phylogeny is based on 16S rRNA-based LTP release 106 by 'The All-Species Living Tree' Project 'The All-Species Living Tree' Project. Notes: * Prokaryotes where no pure (

axenic In biology, axenic (, ) describes the state of a culture in which only a single species, variety, or strain of organism is present and entirely free of all other contaminating organisms. The earliest axenic cultures were of bacteria or unicellul ...

) cultures are isolated or available, i.e. not cultivated or can not be sustained in culture for more than a few serial passages

References

External links

* {{Taxonbar, from=Q136797 Bacteria phyla