Streptomyces

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Streptomyces
Slide culture of a Streptomyces sp.
Slide culture of a Streptomyces sp.
Scientific classification
Domain: Bacteria
Phylum: Actinobacteria
Order: Actinomycetales
Family: Streptomycetaceae
Genus: Streptomyces
Waksman & Henrici 1943
Species

S. ambofaciens
S. achromogenes
S. avermitilis
S. coelicolor
S. clavuligerus
S. felleus
S. ferralitis
S. filamentosus
S. griseus
S. hygroscopicus
S. iysosuperficus
S. lividans
S. noursei
S. scabies
S. somaliensis
S. thermoviolaceus
S. venezuelae
S. violaceoruber
plus ~500 additional species.

Streptomyces is the largest genus of Actinobacteria and the type genus of the family Streptomycetaceae.[1] Over 500 species of Streptomyces bacteria have been described.[2] As with the other Actinobacteria, streptomycetes are Gram-positive, and have genomes with high GC-content.[3] Found predominantly in soil and decaying vegetation, most streptomycetes produce spores, and are noted for their distinct "earthy" odor which results from production of a volatile metabolite, geosmin.

Streptomycetes are characterised by a complex secondary metabolism.[3] They produce over two-thirds of the clinically useful antibiotics of natural origin (e.g., neomycin, chloramphenicol).[4] The now uncommonly-used streptomycin takes its name directly from Streptomyces. Streptomycetes are infrequent pathogens, though infections in human such as mycetoma can be caused by S. somaliensis and S. sudanensis and in plants such as scabies can be caused by S. caviscabies and S. scabies.

Contents

[edit] Genomics

The complete genome of one of the strain, "S. coelicolor" A3(2), was published in 2002.[5] At the time, the "S. coelicolor" genome was thought to contain the largest number of genes of any bacterium.[5] The first complete genome sequence of S. avermitilis was completed in 2003.[6] Each of these genomes form a chromosome with a linear structure, unlike most bacterial genomes which exist in the form of circular chromosomes. The genome sequence of S. scabies, a member of the genus with the ability to cause potato scab disease, has been determined at the Wellcome Trust Sanger Institute and is currently in annotation, with publication scheduled for 2007.

Taxonomically, "S. coelicolor" A3(2) belongs to the species of S. violaceoruber and not a validly described separate species; "S. coelicolor" A3(2) is not to be mistaken for S. coelicolor (Müller) (ATCC 23899).

[edit] Biotechnology

In recent years, biotechnology researchers have begun to use Streptomyces spp. for production of recombinant human proteins. Traditionally, Escherichia coli was the species of choice to host eukaryotic genes since it was well understood and easy to work with.[7][8] However, E. coli introduces problems such as incorrect (or lack of) glycosylation and incorrect protein folding, resulting in insolubility and loss of bioactivity of the product.[9] Streptomyces spp. on the other hand have the ability to secrete correctly folded recombinant proteins into the medium after production simplifying the subsequent purification steps. These properties among others make Streptomyces spp. an attractive alternative to other bacteria such as E. coli and Bacillus subtilis.[9]

[edit] Medicine

Streptomyces is the largest antibiotic producing genus, producing both antibacterials and antifungals, and also a wide range of other bioactive compounds such as immunosuppressants.[10]

[edit] Antifungals

See also: polyene antimycotic

Streptomycetes produce numerous antifungal compounds of medicinal importance, including nystatin (from S. noursei),amphotericin B (from S. nodosus), and natamycin (from S. natalensis).

[edit] Antibacterials

Members of the Streptomyces genus are the source for innumerable antibacterial pharmaceutical agents; among the most important of these are:

[edit] Antiparasitic Drugs

Streptomyces genus is responsible for the production of one of the most widely employed drugs against nematode and arthropod infestations: Ivermectin (Streptomyces avermitilis)

[edit] Other

Less commonly, streptomycetes produce compounds used in other medical treatments: migrastatin (from S. platensis) is an antineoplastic (anti-cancer) drug

[edit] References

  1. ^ Kämpfer P (2006). "The Family Streptomycetaceae, Part I: Taxonomy", The prokaryotes: a handbook on the biology of bacteria (Dworkin, M et al, eds.). Berlin: Springer, 538-604. ISBN 0-387-25493-5. 
  2. ^ Euzéby JP (2008). "Genus Streptomyces". List of Prokaryotic names with Standing in Nomenclature. Retrieved on 2008-09-28.
  3. ^ a b Madigan M, Martinko J (eds.) (2005). Brock Biology of Microorganisms, 11th ed., Prentice Hall. ISBN 0-13-144329-1. 
  4. ^ Kieser T, Bibb MJ, Buttner MJ, Chater KF, Hopwood DA (2000). Practical Streptomyces Genetics, 2nd ed., Norwich, England: John Innes Foundation. ISBN 0-7084-0623-8. 
  5. ^ a b Bentley SD, et al. (2002). "Complete genome sequence of the model actinomycete "Streptomyces coelicolor" A3(2)". Nature 417: 141–147. doi:10.1038/417141a. PMID 12000953. 
  6. ^ Ikeda H; Ishikawa J; Hanamoto A; Shinose M; Kikuchi H; Shiba T; Sakaki Y; Hattori M; Omura S (2003). "Complete genome sequence and comparative analysis of the industrial microorganism Streptomyces avermitilis". Nat. Biotechnol. 21: 526–531. doi:10.1038/nbt820. PMID 12692562, http://www.nature.com/cgi-taf/DynaPage.taf?file=/nbt/journal/v21/n5/abs/nbt820.html. 
  7. ^ Brawner M, Poste G, Rosenberg M, Westpheling J (1991). "Streptomyces: a host for heterologous gene expression". Curr Opin Biotechnol 2 (5): 674–81. doi:10.1016/0958-1669(91)90033-2. PMID 1367716. 
  8. ^ Payne G, DelaCruz N, Coppella S (1990). "Improved production of heterologous protein from Streptomyces lividans". Appl Microbiol Biotechnol 33 (4): 395–400. doi:10.1007/BF00176653. PMID 1369282. 
  9. ^ a b Binnie C, Cossar J, Stewart D (1997). "Heterologous biopharmaceutical protein expression in Streptomyces". Trends Biotechnol 15 (8): 315–20. doi:10.1016/S0167-7799(97)01062-7. PMID 9263479. 
  10. ^ Watve MG, Tickoo R, Jog MM, Bhole BD (November 2001). "How many antibiotics are produced by the genus Streptomyces?". Arch. Microbiol. 176 (5): 386–90. doi:10.1007/s002030100345. PMID 11702082. 

[edit] Further reading

  • Baumberg S (1991). Genetics and Product Formation in Streptomyces. Kluwer Academic. ISBN 978-0306438851. 
  • Gunsalus IC (1986). Bacteria: Antibiotic-producing Streptomyces. Academic Press. ISBN 978-0123072092. 
  • Hopwood DA (2007). Streptomyces in Nature and Medicine: The Antibiotic Makers. Oxford University Press. ISBN 978-0195150667. 

[edit] See also

[edit] External links

Retrieved from "http://en.wikipedia.org/wiki/Streptomyces"
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