Proteobacteria
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robot Adding: [[sv:Proteobacteria]]
{{Taxobox
| color = lightgrey
| name = Proteobacteria
| image = EscherichiaColi NIAID.jpg
| image_width = 250px
| image_caption = ''[[Escherichia coli]]''
| domain = [[Bacteria]]
| phylum = '''Proteobacteria'''
| phylum_authority = Stackebrandt et al., 1986
| subdivision_ranks = [[Order (biology)|Order]]s
| subdivision =
'''Alpha Proteobacteria'''<br>
[[Caulobacteraceae|Caulobacterales]] - e.g. ''[[Caulobacter crescentus|Caulobacter]]''<br>
[[Kordiimonas gwangyangensis|Kordiimonadales]]<br>
[[Parvularcula]]les<br>
[[Rhizobiales]] - e.g. [[Rhizobia]]<br>
[[Rhodobacteraceae|Rhodobacterales]]<br>
[[Rhodospirillales]] - e.g. ''[[Acetobacter]]''<br>
[[Rickettsiales]] - e.g. ''[[Rickettsia]]''<br>
[[Sphingomonadaceae|Sphingomonadales]] e.g. ''[[Sphingomonas]]''<br>
'''Beta Proteobacteria'''<br>
[[Burkholderiales]] - e.g. ''[[Bordetella]]''<br>
[[Hydrogenophilaceae|Hydrogenophilales]]<br>
[[Methylophilaceae|Methylophilales]]<br>
[[Neisseriaceae|Neisseriales]] - e.g. ''[[Neisseria]]''<br>
[[Nitrosomonadales]]<br>
[[Rhodocyclaceae|Rhodocyclales]]<br>
[[Procabacter]]iales<br>
'''Gamma Proteobacteria'''<br>
[[Acidithiobacillales]]<br>
[[Aeromonadales]] - e.g. ''[[Aeromonas]]''<br>
[[Alteromonadales]] - e.g. ''[[Pseudoalteromonas]]''<br>
[[Cardiobacteriaceae|Cardiobacteriales]]<br>
[[Purple sulfur bacteria|Chromatiales]] - purple sulfur bacteria<br>
[[Enterobacteriaceae|Enterobacteriales]] - e.g. ''[[Escherichia coli|Escherichia]]''<br>
[[Legionellales]] - e.g. ''[[Legionella]]''<br>
[[Methylococcaceae|Methylococcales]]<br>
[[Oceanospirillales]]<br>
[[Pasteurellaceae|Pasteurellales]] - e.g. ''[[Haemophilus influenzae|Haemophilus]]''<br>
[[Pseudomonadales]] - e.g. ''[[Pseudomonas]]''<br>
[[Thiotrichales]] - e.g. ''[[Thiomargarita namibiensis|Thiomargarita]]''<br>
[[Vibrionaceae|Vibrionales]] - e.g. ''[[Vibrio]]''<br>
[[Xanthomonadaceae|Xanthomonadales]] - e.g. ''[[Xanthomonas]]''<br>
'''Delta Proteobacteria'''<br>
[[Bdellovibrionaceae|Bdellovibrionales]] - e.g. ''[[Bdellovibrio]]''<br>
[[Desulfobacterales]]<br>
[[Desulfovibrionales]]<br>
[[Desulfurellaceae|Desulfurellales]]<br>
[[Desulfarculaceae|Desulfarcales]]<br>
[[Desulfuromonadales]] - e.g. ''[[Geobacter]]''<br>
[[Myxobacteria|Myxococcales]] - Myxobacteria<br>
[[Syntrophobacterales]]<br>
'''Epsilon Proteobacteria'''<br>
[[Campylobacterales]] - e.g. ''[[Helicobacter pylori|Helicobacter]]''<br>
[[Nautiliaceae|Nautiliales]]<br>
}}
The '''Proteobacteria''' are a major group ([[phylum]]) of [[bacteria]]. They include a wide variety of [[pathogen]]s, such as ''[[Escherichia]]'', ''[[Salmonella]]'', ''[[Vibrio]]'', ''[[Helicobacter]]'', and many other notable genera.<ref name=Brock>{{cite book | author = Madigan M; Martinko J (editors). | title = Brock Biology of Microorganisms | edition = 11th ed. | publisher = Prentice Hall | year = 2005 | id = ISBN 0131443291 }}</ref> Others are free-living, and include many of the bacteria responsible for [[nitrogen fixation]]. The group is defined primarily in terms of [[ribosomal RNA]] (rRNA) sequences, and is named for the Greek god [[Proteus]] (also the name of a [[Proteus (bacterium)|bacterial genus]] within the Proteobacteria), who could change his shape, because of the great diversity of forms found in this group.<ref name=Tree_of_Life>{{cite web | title=Proteobacteria | work=Discover Life: Tree of Life | url=http://stri.discoverlife.org/mp/20m?tree=Proteobacteria&res=800 | accessdate=2007-02-09}}</ref>
All Proteobacteria are [[Gram-negative]], with an [[outer membrane]] mainly composed of [[lipopolysaccharide]]s. Many move about using [[flagellum|flagella]], but some are non-motile or rely on [[bacterial gliding]]. The last include the [[myxobacteria]], a unique group of bacteria that can aggregate to form multicellular fruiting bodies. There is also a wide variety in the types of [[metabolism]]. Most members are facultatively or obligately [[anaerobic organism|anaerobic]] and [[heterotrophic]], but there are numerous exceptions. A variety of genera, which are not closely related to each other, convert energy from light through [[photosynthesis]]. These are called [[purple bacteria]], referring to their mostly reddish pigmentation.
[[Cavalier-Smith]] has postulated that Proteobacteria is part of the bacterial clade [[Gracilicutes]].
==Sections/Classes==
The proteobacteria are divided into five sections, referred to by the [[Greek letters]] alpha through epsilon, again based on rRNA sequences. These are often treated as classes. Although it has been suggested previously that the Gamma Proteobacteria are [[paraphyly|paraphyletic]] to the Beta Proteobacteria, recent molecular data suggests that this is not so.
===Alphaproteobacteria===
The Alphaproteobacteria comprise most phototrophic genera, but also several genera metabolising C1-compounds (e.g. ''Methylobacterium''), symbionts of plants (e.g. [[Rhizobia]]) and animals, and a group of dangerous pathogens, the [[Rickettsiaceae]]. Moreover the precursors of the [[mitochondria]] of eukaryotic cells are thought to have originated in this bacterial group. (See [[endosymbiotic theory]].)
===Betaproteobacteria===
The Betaproteobacteria consist of several groups of aerobic or facultative bacteria which are often highly versatile in their degradation capacities, but also contain chemolithotrophic genera (e.g. the ammonia-oxidising genus ''Nitrosomonas'') and some phototrophs (genera ''Rhodocyclus'' and ''Rubrivivax''). Beta Proteobacteria play an important role in nitrogen fixation in various types of plants, oxidizing ammonium to produce nitrite- an important chemical for plant function. Many of them are found in environmental samples, such as waste water or soil. Pathogenic species within this class are the [[Neisseriaceae]] ([[gonorrhea]] and meningoencephalitis) and species of the genus ''[[Burkholderia]]''.
===Gammaproteobacteria===
[[Image:Vibrio cholerae.jpg|100px|left|''[[Vibrio cholerae]]''|Vibrio cholerae]]
The Gammaproteobacteria comprise several medically and scientifically important groups of bacteria, such as the [[Enterobacteriaceae]], [[Vibrionaceae]] and [[Pseudomonadaceae]]. An exceeding number of important pathogens belongs to this class, e.g. ''[[Salmonella]]'' ([[enteritis]] and [[typhoid fever]]), ''[[Yersinia pestis]]'' (plague), ''[[Vibrio]]'' (cholera), ''[[Pseudomonas aeruginosa]]'' (lung infections in hospitalized or [[cystic fibrosis]] patients), and ''[[Escherichia coli O157:H7]]'' (food poisoning).
===Deltaproteobacteria===
The Deltaproteobacteria comprise a branch of predominantly aerobic genera, the fruiting-body-forming [[myxobacteria]], and a branch of strictly anaerobic genera, which contains most of the known [[sulfate-reducing bacteria|sulfate-]] (''Desulfovibrio'', ''Desulfobacter'', ''Desulfococcus'', ''Desulfonema'', etc.) and [[sulfur-reducing bacteria]] (e.g. ''Desulfuromonas'') alongside several other anaerobic bacteria with different physiology (e.g. ferric iron-reducing ''[[Geobacter]]'' and syntrophic ''Pelobacter'' and ''Syntrophus'' species).
===Epsilonproteobacteria===
[[Image:Helicobacter pylori.jpg|60px|left|''[[Helicobacter pylori]]'' ''Helicobacter pylori'']]
The Epsilonproteobacteria consist of only a few genera, mainly the curved to spirilloid ''[[Wolinella]]'', ''[[Helicobacter]]'', and ''[[Campylobacter]]''. Most of the known species inhabit the digestive tract of animals and humans and serve as [[symbiosis|symbionts]] (''Wolinella'' in [[cattle|cows]]) or [[pathogen]]s (''Helicobacter'' in the stomach, ''Campylobacter'' in the duodenum). There have also been numerous environmental sequences of epsilons recovered from [[hydrothermal vent]] and [[cold seep]] habitats.
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==References==
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==External links==
{{Wikispecies}}
* [http://www.palaeos.org/Proteobacteria Proteobacteria information from [[Palaeos]]]
[[Category:Bacteria]]
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