# Actinobacterias

| Actinobacterias |
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| *Actinomycetota* **2021**  |
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|  Instancia de
taxon  |
|  Categoría taxonómica
filo  |
|  Tipo taxonómico
Actinomyces  |
|  Sinónimo taxonómico
*Actinobacterias* *Actinobacteriota*  |

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|  Subdivisións

* ?Nostocoida limicola I ♠
* ?*Candidatus* Planktophila Jezbera et al. 2009
* ?*Cathayosporangium* ♠ Runmao et al. 1995
* ?*Tonsillophilus suis* ♠ Azuma and Bak 1980
* Acidimicrobidae Stackebrandt et al. 1997 emend. Zhi et al. 2009
	+ Acidimicrobiales Stackebrandt et al. 1997 emend. Zhi et al. 2009
* Coriobacteridae Stackebrandt et al. 1997 emend. Zhi et al. 2009
	+ Coriobacteriales Stackebrandt et al. 1997 emend. Zhi et al. 2009
* Nitriliruptoridae Kurahashi et al. 2010
	+ Nitriliruptorales Sorokin et al. 2009
	+ Euzebyales Kurahashi et al. 2010
* Rubrobacteridae Rainey et al. 1997 emend. Zhi et al. 2009
	+ Gaiellales Albuquerque et al. 2012
	+ Rubrobacterales Rainey et al. 1997 emend. Zhi et al. 2009
	+ Solirubrobacterales Reddy and Garcia-Pichel 2009
	+ Thermoleophilales Reddy and Garcia-Pichel 2009
* Actinobacteridae Stackebrandt et al. 1997 emend. Zhi et al. 2009
	+ Bifidobacteriales Stackebrandt et al. 1997 emend. Zhi et al. 2009
	+ Actinomycetales Buchanan 1917 emend. Zhi et al. 2009
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| Clasificación taxonómica |
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|  **Reino** | *Bacillati* |
|  **Filo** | Actinomycetota   |
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| Wikidata C:Commons |

As **actinobacterias** (**Actinobacteria**, sinónimo **Actinomycetota**) son un amplo grupo de bacterias grampositivas que presentan unha alta proporción GC (guanina-citosina) nos seus xenomas, e que son consideradas un filo. Poden vivir en ambientes terrestres e acuáticos. É un dos filos principais de bacterias. No estudo do grupo poden utilizarse análises da secuencia do seu encima glutamina sintetase.

A maioría das Actinobacteria de importancia médica ou económica pertencen á subclase Actinobacteridae, orde Actinomycetales. Algunhas causan enfermidades nos humanos, como a difteria, ou a tuberculose. Outras son fonte de antibióticos, como *Streptomyces*. Outras aprovéitanse para a produción de substancias químicas ou na produción de certos queixos (*Propionibacterium*). Moitas son de vida libre.

## Características

Entre as Actinobacteria están algunhas das bacterias máis comúns no solo, auga doce, e vida mariña. Xogan un importante papel na descomposición de materiais orgánicos, como a celulosa e quitina, e na reciclaxe da materia orgánica e ciclo do carbono. Repoñen os nutrientes que perde o solo e son importantes na formación do humus. Outras Actinobacteria viven en plantas e animais, e algunhas son patóxenas, como *Mycobacterium*, *Corynebacterium*, *Nocardia*, *Rhodococcus* e algúns *Streptomyces*.

As Actinobacteria son coñecidas como produtores de metabolitos secundarios de grande interese farmacolóxico e comercial, como aminoácidos, vitaminas, saborizantes, derivados lácticos ou antibióticos. En 1940 Selman Waksman descubriu que as bacterias do solo que estaba estudando producían actinomicina, un descubrimento polo cal recibiu o premio Nobel. Desde entón, descubríronse centos de antibióticos naturais producidos por estes microorganismos terrestres, especialmente os do xénero *Streptomyces*.

Algunhas Actinobacteria forman filamentos ramificados, que pola súa forma lembran aos micelios dos fungos (cos cales estas bacterias non están emparentados), e por esa razón foron inicialmente clasificadas co vello nome de Actinomycetes. A maioría das Actinobacteria son aerobias, pero algunhas, como *Actinomyces israelii*, poden crecer en condicións anaeobias. A diferenza dos Firmicutes, que son o outro gran grupo de bacterias grampositivas, as Actinobacteria teñen un ADN con alto contido GC. Algunhas especies producen esporas externas.

Algúns tipos de Actinobacteria son responsables do peculiar cheiro que emana do chan despois da chuvia, principalmente nos climas cálidos. A substancia química que produce este cheiro denomínase xeosmina (terpenoide).

## Filoxenia

*Véxase tamén**:* Taxonomía bacteriana.
O cladograma representa a taxonomía aceptada actualmente das Actinobacteria, baseada na LPSN ( *List of Prokaryotic names with Standing in Nomenclature*) e no NCBI (*National Center for Biotechnology Information*)
e a filoxenia está baseada nas secuencias do ARNr 16S do LTP 106 do proxecto *The All-Species Living Tree*.

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|   |

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?Nostocoida limicola I ♠ |
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?*Candidatus* Planktophila limnetica Jezbera et al. 2009 |
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?*Cathayosporangium alboflavum* ♠ Runmao et al. 1995 |
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?*Tonsillophilus suis* ♠ Azuma e Bak 1980 |
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|   | *Rubrobacter* Suzuki et al. 1989 |
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|   Thermoleophilidae |

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?*Gaiella occulta* Albuquerque et al. 2012 |
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|   | *Thermoleophilum* Zarilla e Perry 1986 |
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Solirubrobacterales |
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Coriobacteriaceae |
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Acidimicrobiales |
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|  Nitriliruptoridae |

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|   | *Euzebya tangerina* Kurahashi et al. 2010 |
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|   | *Nitriliruptor alkaliphilus* Sorokin et al. 2009 |
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|   Actinomycetales |

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?*Boyliae praeputiale* ♠ Yates et al. 2002 |
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?*Frankia alni* ♪ (Woronin 1866) Von Tubeuf 1895 |
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?*Motilibacter peucedani* Lee 2012 |
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|   | *Acidothermus cellulolyticus* Mohagheghi et al. 1986 |
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Jiangellaceae |
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Micromonosporaceae |
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Propionibacterineae |
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|   | *Actinocatenispora* Thawai et al. 2006 emend. Seo e Lee 2009 |
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Glycomycetaceae |
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Streptosporangineae |
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Pseudonocardiaceae [incl. *Actinopolyspora*] |
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Corynebacterineae |
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Catenulisporineae |
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|   | *Streptomyces* Waksman e Henrici 1943 emend. Witt e Stackebrandt 1991 [incl. *Kitasatospora* & *Streptacidiphilus*] |
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|   | *Sporichthya* Lechevalier et al. 1968 |
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Cryptosporangiaceae |
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Geodermatophilaceae |
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Nakamurellaceae |
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Kineosporiaceae |
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|   | *Kineococcus* Yokota et al. 1993 |
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|   | *Angustibacter luteus* Tamura et al. 2010 |
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Micrococcineae [incl. Actinomycetaceae & Bifidobacteriaceae] |
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Notas:

♪ Procariotas dos que non hai cultivos puros (axénicos) illados ou dispoñibles, porque non poden ser cultivados ou duran pouco.

♠ Cepas atopadas no NCBI (*National Center for Biotechnology Information*) pero non na LPSN.

## Notas

## Véxase tamén

### Ligazóns externas

* Actinomycetes genome database