Actinomycetaceae

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Actinomycetaceae
Actinomyces israelii

Actinomyces israelii

Systematics
Domain : Bacteria (bacteria)
Department : Actinobacteria
Order : Actinomycetales
Subordination : Actinomycineae
Family : Actinomycetaceae
Scientific name
Actinomycetaceae
Buchanan 1918, emend. Zhi et al. 2009

Actinomycetaceae is a family of bacteria - order Actinomycetales , to which eight genera are included (as of 2020). The genus Actinomyces contains most of the species . Characteristic of the representatives of the Actinomycetaceae are elongated, often branched cells , with the exception of the genus Mobiluncus without active movement , predominantly anaerobic growth and positive behavior in the Gram stain .

The Actinomycetaceae family is often referred to as "actinomycetes" or "actinomycetes". However, these names are ambiguous because they also denote the order Actinomycetales and the genus Actinomyces.

Shape, cell structure

Actinomycetes usually form straight or curved rod-shaped cells with a diameter of 0.2-3.0 µm. The length is very different, there are short coccoid cells and long filamentous cells up to a length of 50 µm or even more. Some species form small, branched mycelia . The long-thread forms and mycelia occasionally multiply by breaking up into short cells (segmentation). The representatives of the Actinomycetaceae are gram-positive . Active movement occurs only in the genus Mobiluncus , through one flagellum each or through several (up to 8) arranged at one end of the cell. In this genus there are also forms that have a typical cell wall of Gram-positive bacteria, but which is so thin that they behave gram-variable or gram-negative in Gram staining.

metabolism

The representatives of the Actinomycetaceae family are predominantly anaerobic, some are facultative aerobic , only a few have the enzyme catalase . In some types is a high carbon dioxide - (CO 2 ) or bicarbonate (HCO 3 - ) concentration in the nutrient medium enables growth under aerobic conditions. Most actinomycetes require a complex range of nutrients to grow. Often they have a fermentative energy metabolism in which carbohydrates are converted into organic acids . In the genus Varibaculum comes reduction of nitrate (NO 3 - ) to nitrite (NO 2 - ) in front, wherein the species Mobiluncus is fumarate to malate reduced and some of these species can reduce nitrate.

Occurrence, way of life

Most actinomycetes are found in warm-blooded vertebrates , either as pathogens or as commensals . The optimum temperature for growth is therefore relatively high: 30 - 37 ° C. The pathogens cause various diseases , including a. Actinomycoses .

Systematics

External system

The order Actinomycetales is very species-rich and is divided into several suborders and families, in addition to the suborder Actinomycineae with the family Actinomycetaceae, for example, the suborder Corynebacterineae with the families Mycobacteriaceae and Nocardiaceae , to which the medically relevant genera Mycobacterium and Nocardia belong with the families Brevibacteriaceae and Micrococcaceae .

Internal system

The Actinomycetaceae family includes the following genera (as of 2020), plus a selection of species:

  • Actinobaculum Lawson et al. 1997 emend. Yassin et al. 2015
  • Mobiluncus Spiegel & Roberts 1984 emend. Hoyles et al. 2004
  • Varibaculum Hall et al. 2003 emend. Glaeser et al. 2017

Changes in the system and synonyms

The species Trueperella pyogenes has several synonyms . It was described in 1903 by Glage as " Bacillus pyogenes ", in 1918 by Eberson as Corynebacterium pyogenes to the genus Corynebacterium and in 1982 by Reddy as Actinomyces pyogenes to the genus Actinomyces . In 1997, phylogenetic analyzes of some Actinomyces species led to the establishment of further genera in the Actinomycetaceae family, in this context the species was reclassified as Arcanobacterium pyogenes . Comparative studies of chemotaxonomy and phylogenetics then led to the classification as Trueperella pyogenes ( Glage 1903) Yassin et al. 2011 in the genus Trueperella .

In 2004, Hoyles et al. Showed that the species Falcivibrio grandis Hammann et al. 1984 (the type species of the genus Falcivibrio Hammann et al. 1984) is a heterotypical synonym of the species Mobiluncus mulieris Spiegel & Roberts 1984 described later . According to rule 37a of the International Code of Nomenclature of Bacteria (Bacteriological Code), the genus name Falcivibrio is no longer valid and the species of this genus have been placed under the genus Mobiluncus .

literature

  • Klaus P. Schaal, Atteyet F. Yassin, Erko Stackebrandt : The Family Actinomycetaceae: The Genera Actinomyces, Actinobaculum, Arcanobacterium, Varibaculum, and Mobiluncus. In: Martin Dworkin, Stanley Falkow, Eugene Rosenberg, Karl-Heinz Schleifer, Erko Stackebrandt (Eds.): The Prokaryotes - A Handbook on the Biology of Bacteria . 3rd edition, Vol. 3: Archaea. Bacteria: Firmicutes, Actinomycetes . Springer Verlag, New York 2006, pp. 430-537, ISBN 978-0-387-25493-7 (print), ISBN 978-0-387-30743-5 (online), doi : 10.1007 / 0-387-30743 -5_21 .

Individual evidence

  1. ^ A b Jean Euzéby, Aidan C. Parte: Familiy Actinomycetaceae. In: List of Prokaryotic names with Standing in Nomenclature, Systematics of Bacteria (LPSN) . Retrieved February 8, 2020 .
  2. ↑ a b Jean Euzéby, Aidan C. Parte: Classification of domains and phyla - Hierarchical classification of prokaryotes (bacteria). In: List of Prokaryotic names with Standing in Nomenclature, Systematics of Bacteria (LPSN) . Retrieved February 8, 2020 .
  3. ^ Jean Euzéby, Aidan C. Parte: Genus Arcanobacterium. In: List of Prokaryotic names with Standing in Nomenclature, Systematics of Bacteria (LPSN) . Retrieved February 8, 2020 .
  4. ↑ L. Hoyles, MD Collins, E. Falsen, N. Nikolaitchouk, AL McCartney: Transfer of members of the genus Falcivibrio to the genus Mobiluncus, and emended description of the genus Mobiluncus . In: Systematic and Applied Microbiology . tape 27 , no. 1 , February 2004, p. 72-83 , doi : 10.1078 / 0723-2020-00260 , PMID 15053324 .