Streptomyces

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Streptomyces
Streptomyces sp.

Streptomyces sp.

Systematics
Domain : Bacteria (bacteria)
Department : Actinobacteria
Order : Actinomycetales
Subordination : Streptomycineae
Family : Streptomycetaceae
Genre : Streptomyces
Scientific name
Streptomyces
Waksman & Henrici 1943
species

Streptomyces is a very species-rich genus of Actinobacteria . The species in this genus are gram-positive , aerobic , mycelium- forming, multicellular, form spores and have a high GC content . They occur mainly in soils , where they form fragrances, especially geosmin , with the characteristic odor of the forest soil. Numerous Streptomyces species produce antibiotics that are used in human and veterinary medicine.

features

Appearance

The representatives of the genus Streptomyces are gram-positive bacteria. As with many representatives of the Actinomycetales order , Streptomyces also develops cells in the form of filaments. These elongated and branched cells form plexuses, which are also known as mycelium . The filaments have a diameter of 0.5 to 1.0 µm and often no transverse walls in the growth phase.

Similar to fungi , a distinction can be made between two types of growth of Streptomyces : The substrate mycelium , which spreads in the liquid or solid nutrient medium, and the aerial mycelium that grows into the gas space above. In older cultures, transverse walls are again formed in the cell walls at the ends of the filaments of the aerial mycelium, so that chains of several, mostly spherical spores are formed by segmentation . These spores, which are to be regarded as bacterial exospores , therefore differ fundamentally from the endospores , which z. B. be formed by the bacterial genera Clostridium and Bacillus .

Chemotaxonomic Features

As a representative of the Actinomycetales in the Actinobacteria department , Streptomyces is one of the bacteria with a high GC content , ie a high proportion of the nucleobases guanine and cytosine in the bacterial DNA . Genetic studies have shown a GC content of 69 to 75 mole percent.

Hyphae from a strain of Streptomyces that synthesizes a red, cytotoxic compound

The complete genome of Streptomyces coelicolor was sequenced and published in 2002. The genome of Streptomyces avermitilis has also been sequenced. It contains most of the genes of all bacteria examined so far. Another feature that is rare for prokaryotes is that the chromosome is linear rather than circular. The genome of the species examined so far is extraordinarily large for bacteria, the genome size of the bacterial chromosome in Streptomyces coelicolor is 8668 kilobase pairs (kb), which is almost twice the genome size of Escherichia coli (4600 kb).

Growth and metabolism

The representatives of the genus Streptomyces are aerobic , so they need oxygen for their growth. Furthermore, they are characterized by a pronounced secondary metabolism . They produce a large number of antibiotics that are used in medicine. The antibiotic streptomycin, which is rarely used today, is named after the genus Streptomyces .

Occurrence and meaning

Streptomyces occurs mainly in soils . Many species form fragrances, especially geosmin , with the characteristic odor of the forest soil.

The many Streptomyces species that produce antibiotics are important for human and veterinary medicine . In addition, Streptomyces avidinii produces the biotin- binding protein streptavidin . Similar compounds were isolated from Streptomyces venezuelae and are designated as streptavidin v1 and v2. Compared to the amino acid sequence of the protein streptavidin, one or nine amino acids are changed. Cobalamins can be obtained as a by-product of the production of streptomycin from Streptomyces griseus .

Potato scab caused by Streptomyces scabiei

Streptomyces rarely occurs as a pathogen, in humans Streptomyces somaliensis and " Streptomyces sudanensis " are relevant. In plants, Streptomyces caviscabies and Streptomyces scabiei (previously incorrectly referred to as Streptomyces scabies ) cause the potato scab . The systematics of some of these species is controversial.

Systematics

The genus Streptomyces is very species-rich. Currently (as of 2013) more than 600 species and subspecies are known. In the bacteria database kept as a reference for the systematics of bacteria , the species are divided into three files. Streptomyces albus is the type species of the genus.

Antibiotic producers

Here are some examples of species that are important as antibiotic producers:

Changed system

The delimitation of the numerous Streptomyces species from one another is quite controversial. Studies from 2005 showed that the species Streptomyces caviscabies Goyer et al. 1996 coincides with the already known species Streptomyces griseus ( Krainsky 1914) Waksman & Henrici 1948 and therefore has to be renamed. This was confirmed in 2008 by studies by Guo et al. refuted. Investigations from 2010 showed that it is instead identical to the already known species Streptomyces fimicarius ( Duché 1934) Waksman & Henrici 1948. This species was then discovered in 2012 by Kim et al. identified as a synonym of Streptomyces setonii , so that according to the current system it is now Streptomyces setonii ( Millard & Burr 1926) Waksman 1953 emend. Kim et al. 2012 acts.

By molecular biological studies is checked whether the variety of species inventory, or whether some species are so closely related to each other that they become a kind - should be combined - possibly with subspecies. The methods used in an investigation from 2010 include DNA – DNA hybridization and multi- locus sequence analysis (MLSA). The hybridization technique serves to demonstrate the structural relationship of nucleic acids and thus to elucidate the phylogenetic relationship. In the MLSA, the investigation is limited to certain genes that are particularly typical of a species or genus. Sequence analysis of the 2010 was limited to the detection of five housekeeping genes (English housekeeping genes , non-regulated genes regardless of cell type, cell stage and external influences expressed are). As a result of the investigation, it was proposed to combine the 29 species and three subspecies on which the investigation was based into only eleven species.

The species " Streptomyces sudanensis ", which is significant for human medicine, has not yet been published in accordance with the rules of the International Code of Nomenclature of Bacteria (ICNB) and is therefore placed in quotation marks. The bacterial strains examined are closely related to Streptomyces somaliensis .

See also

Web links

Commons : Streptomyces  - collection of images, videos and audio files

swell

literature

Individual evidence

  1. ↑ a b c d e f g h i j k l m Michael T. Madigan, John M. Martinko, Jack Parker: Brock Mikrobiologie. German translation edited by Werner Goebel, 1st edition. Spectrum Akademischer Verlag GmbH, Heidelberg / Berlin 2000, ISBN 978-3-8274-0566-1 , pp. 440-441, 577-582.
  2. ↑ a b S. D. Bentley, KF Chater u. a .: Complete genome sequence of the model actinomycete Streptomyces coelicolor A3 (2). In: Nature . Volume 417, No. 6885, May 2002, pp. 141-147, ISSN  0028-0836 . doi: 10.1038 / 417141a . PMID 12000953 .
  3. ↑ J. Altenbuchner, M. Redenbach: Why do some bacteria have linear chromosomes and plasmids? (PDF) BIOspektrum 2/2002, pp. 158–163.
  4. ↑ a b E. A. Bayer, T. Kulik, R. Adar, M. Wilchek: Close similarity among streptavidin-like, biotin-binding proteins from Streptomyces. In: Biochimica et Biophysica Acta . Volume 1263, No. 1, July 1995, pp. 60-66, ISSN  0006-3002 . PMID 7632734 .
  5. ↑ H. Hager, F. v. Bruchhausen, R. Batty, G. Wurm: Hager's handbook of pharmaceutical practice. 5th edition, volume 1 Goods and Services , Springer, 1995, ISBN 978-3-540-58958-7 , p. 37.
  6. ↑ a b E. T. Quintana, K. Wierzbicka u. a .: Streptomyces sudanensis sp. nov., a new pathogen isolated from patients with actinomycetoma In: Antonie van Leeuwenhoek. Volume 93, Number 3, March 2008, pp. 305-313, ISSN  0003-6072 . doi: 10.1007 / s10482-007-9205-z
  7. ^ A b c d Jean Euzéby, Aidan C. Parte: Genus Streptomyces File 3. In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Retrieved December 23, 2013 .
  8. ↑ DH Lambert, R. Loria: Streptomyces scabies sp. nov., nom. rev. In: International Journal of Systematic Bacteriology. Volume 39, Number 4, October 1989, pp. 387-392, ISSN  0020-7713 . doi: 10.1099 / 00207713-39-4-387 .
  9. ^ A b Prokaryotic Nomenclature Up-to-date. In: Website of the Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures GmbH . Retrieved December 23, 2013 .
  10. ↑ a b c Jean Euzéby, Aidan C. Part: Genus Streptomyces File 1. In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Retrieved December 23, 2013 .
  11. ↑ Jean Euzéby, Aidan C. Parte: Genus Streptomyces File 2. In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Retrieved December 23, 2013 .
  12. ↑ A. Nagakawa, S. Omura: Structure of Cervinomycine, a novel Xantone Antibiotic against Anaerobe and Mycoplasma. In: Journal of Antibiotics . Pp. 301-308, Vol. XL, No. 3, August 30, 1986, doi: 10.7164 / antibiotics.40.301 .
  13. ↑ C. Reading, M. Cole: Clavulanic acid: a beta-lactamase-inhiting beta-lactam from Streptomyces clavuligerus. In: Antimicrobial agents and chemotherapy. Volume 11, Number 5, May 1977, pp. 852-857, PMID 879738 , PMC 352086 (free full text).
  14. ↑ a b C. E. Higgens, RE Kastner: Streptomyces clavuligerus sp. nov., a β-Lactam Antibiotic Producer. In: International Journal of Systematic and Evolutionary Bacteriology. Volume 21, Number 4, October 1971, pp. 326-331, doi : 10.1099 / 00207713-21-4-326 .
  15. ↑ Entry on Mitomycins. In: Römpp Online . Georg Thieme Verlag, accessed on April 26, 2011.
  16. ↑ Entry on lavendamycin. In: Römpp Online . Georg Thieme Verlag, accessed on April 26, 2011.
  17. ^ H. Drautz, W. Keller-Schierlein, H. zahner: metabolic products of microorganisms. In: Archives of Microbiology. Pp. 175-190, Volume 106, No. 3 / January 1975.
  18. ↑ X. Rong, Y. Huang: Taxonomic evaluation of the Streptomyces griseus clade using multilocus sequence analysis and DNA-DNA hybridization, with proposal to combine 29 species and three subspecies as 11 genomic species. In: International journal of systematic and evolutionary microbiology. Volume 60, No. 3, March 2010, pp. 696-703, ISSN  1466-5026 . doi: 10.1099 / ijs.0.012419-0 . PMID 19656940 .