''Shewanella putrefaciens'' is a

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 ...

pleomorphic

bacterium 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 ...

. It has been isolated from marine environments, as well as from anaerobic sandstone in the Morrison Formation in

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

. ''S. putrefaciens'' is also a

facultative anaerobe A facultative anaerobic organism is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent. Some examples of facultatively anaerobic bacteria are '' Staphylococc ...

with the ability to

reduce Reduction, reduced, or reduce may refer to: Science and technology Chemistry * Reduction (chemistry), part of a reduction-oxidation (redox) reaction in which atoms have their oxidation state changed. ** Organic redox reaction, a redox react ...

iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...

and

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

metabolically Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...

; that is, it can use iron and manganese as the terminal electron acceptor in the electron transport chain (in contrast to obligate aerobes which must use oxygen for this purpose). It is also one of the organisms associated with the odor of rotting fish, as it is a marine organism which produces

trimethylamine Trimethylamine (TMA) is an organic compound with the formula N(CH3)3. It is a colorless, hygroscopic, and flammable tertiary amine. It is a gas at room temperature but is usually sold as a 40% solution in water. (It is also sold in pressurized ...

(hence the species name putrefaciens, from

putrid Putrefaction is the fifth stage of death, following pallor mortis, algor mortis, rigor mortis, and livor mortis. This process references the breaking down of a body of an animal, such as a human, post-mortem. In broad terms, it can be viewed ...

). In both solid and liquid media, ''S. putrefaciens'' is often recognizable by its bright pink color. On solid media, the colonies are round, fast-growing, and pink. The organism is also fast-growing in liquid media, and there will give the liquid an overall pink hue. On blood agar plates, the colonies are typically convex and large, with a brown pigment, and cause “greening” of the agar around the colonies. ''S. putrefaciens'' are non-lactose fermenters on MacConkey agar. As with all ''Shewanella'', this organism produces hydrogen sulfide on TSI. Although it is very rare for it to act as a human pathogen, there have been cases of infections and bacteremia caused by ''S. putrefaciens''. ''S. putrefaciens'' is one of several species that have been shown to derive energy by reducing U(VI) to U(IV), which is thought to be important in making Uranium deposits. In fact, strain CN32 is very metabolically versatile and is capable of reducing metals, metalloids, and even radionuclides in place of oxygen during anaerobic growth. This is known to include (but is not necessarily limited to) Fe(III)->Fe(II), Mn(IV)->(via Mn(III) intermediate)->Mn(II), V(V)->V(IV), Tc(VII)->Tc(V/IV) and U(VI)->U(IV).

References

External links

*
Type strain of ''Shewanella putrefaciens'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
Alteromonadales Bacteria described in 1986 {{Alteromonadales-stub

See also

References

External links