''Spirillum'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

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 wa ...

bacteria in the family ''

Spirillaceae Spirillaceae is a family in the order '' Nitrosomonadales'' in the class ''Betaproteobacteria'' of the bacteria. Only one genus, ''Spirillum ''Spirillum'' is a genus of Gram-negative bacteria in the family '' Spirillaceae'' of the '' Nitro ...

'' of the ''

Nitrosomonadales The NitrosomonadalesBoden, R; Hutt, LP, Rae AW (2017) Reclassification of ''Thiobacillus aquaesulis'' (Wood & Kelly, 1995) as ''Annwoodia aquaesulis'' gen. nov., comb. nov., transfer of ''Thiobacillus'' (Beijerinck, 1904) from the ''Hydrogenophil ...

'' of the ''

Betaproteobacteria Betaproteobacteria are a class of Gram-negative bacteria, and one of the eight classes of the phylum Pseudomonadota (synonym Proteobacteria). The ''Betaproteobacteria'' are a class comprising over 75 genera and 400 species of bacteria. Togeth ...

''.Garrity, George M.; Brenner, Don J.; Krieg, Noel R.; Staley, James T. (eds.) (2005). Bergey's Manual of Systematic Bacteriology, Volume Two: The Proteobacteria, Part C: The Alpha-, Beta-, Delta-, and Epsilonproteobacteria. New York, New York: Springer. pp. 354–361. .Podkopaeva (D.), Grabovich (M.), Kuever (J.), Lysenko (A.M.), Tourova (T.P.), Kolganova (T.V.) and Dubinia (G.): Proposal of Spirillum winogradskyi sp. nov., a novel microaerophilic species, an amended description of the genus Spirillum and Request for an Opinion regarding the status of the species Spirillum volutans Ehrenberg 1832. Int. J. Syst. Evol. Microbiol., 2009, 59, 2916-2920. There are two species of ''Spirillum'' with validly or effectively published names - ''

Spirillum winogradskyi ''Spirillum winogradskyi'' is a gram-negative, bacterium from the genus of Spirillum ''Spirillum'' is a genus of Gram-negative bacteria in the family '' Spirillaceae'' of the '' Nitrosomonadales'' of the '' Betaproteobacteria''.Garrity, Geor ...

'' and ''

Spirillum volutans ''Spirillum volutans'' is a gram-negative, bacterium from the genus of Spirillum ''Spirillum'' is a genus of Gram-negative bacteria in the family '' Spirillaceae'' of the '' Nitrosomonadales'' of the '' Betaproteobacteria''.Garrity, George M ...

''. Other "species" classified as ''Spirillum'' such as "''

Spirillum minus ''Spirillum minus'' is an organism associated with rat-bite fever (specifically sodoku) that has never been fully identified and was assigned to the genus ''Spirillum'' in 1887 based on morphology, although it is not a validly published name. A ...

''", "''

Spirillum pleomorphum ''Spirillum'' is a genus of Gram-negative bacteria in the family '' Spirillaceae'' of the '' Nitrosomonadales'' of the ''Betaproteobacteria''.Garrity, George M.; Brenner, Don J.; Krieg, Noel R.; Staley, James T. (eds.) (2005). Bergey's Manual o ...

''", and "''

Spirillum pulli ''Spirillum'' is a genus of Gram-negative bacteria in the family '' Spirillaceae'' of the '' Nitrosomonadales'' of the ''Betaproteobacteria''.Garrity, George M.; Brenner, Don J.; Krieg, Noel R.; Staley, James T. (eds.) (2005). Bergey's Manual o ...

''" are of uncertain phylogeny and in any case, these are names that have never been validly or effectively published and thus have no standing in nomenclature.

Morphology

Members of the genus ''Spirillum'' are large, elongate, spiral shaped, rigid cells. Some have tufts of amphitrichous flagella at both poles. They are

microaerophilic A microaerophile is a microorganism that requires environments containing lower levels of dioxygen than that are present in the atmosphere (i.e. < 21% O₂; typically 2–10% O₂) for optimal growth. A more r ...

and usually found in stagnant freshwater rich in organic matter.

References

External links

* Nitrosomonadales Bacteria genera {{Betaproteobacteria-stub