Streptomyces

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Streptomyces
Streptomyces sp 01.png
Slide culture of a Streptomyces species
Scientific classification
Kingdom: Bacteria
Phylum: Actinobacteria
Class: Actinobacteria
Order: Actinomycetales
Family: Streptomycetaceae
Genus: Streptomyces
Waksman & Henrici 1943
Diversity
About 550 species
Synonyms

Streptoverticillium

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 that 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 and chloramphenicol).[4] The now uncommonly used streptomycin takes its name directly from Streptomyces. Streptomycetes are infrequent pathogens, though infections in humans, such as mycetoma, can be caused by S. somaliensis and S. sudanensis, and in plants can be caused by S. caviscabies, S. acidiscabies, S. turgidiscabies and S. scabies.

Taxonomy[edit]

Streptomyces is the type genus of the family Streptomycetaceae[5] and currently covers close to 576 species with the number increasing every year.[6] Acidophilic and acid-tolerant strains that were initially classified under this genus have later been moved to Kitasatospora (1997) [7] and Streptacidiphilus (2003).[8] Species nomenclature are usually based on their color of hyphae and spores.

Saccharopolyspora erythraea was formerly placed in the present genus, too (as Streptomyces erythraeus).

Morphology[edit]

The genus Streptomyces includes aerobic, Gram-positive, filamentous bacteria that produce well-developed vegetative hyphae (between 0.5-2.0 µm in diameter) with branches. They form a complex substrate mycelium that aids in scavenging organic compounds from their substrates.[9] Although the mycelia and the aerial hyphae that arise from them are amotile, mobility is achieved by dispersion of spores.[9] Spore surfaces may be hairy, rugose, smooth, spiny or warty.[10] In some species, aerial hyphae consist of long, straight filaments, which bear 50 or more spores at more or less regular intervals, arranged in whorls (verticils). Each branch of a verticil produces, at its apex, an umbel, which carries from two to several chains of spherical to ellipsoidal, smooth or rugose spores.[9] Some strains form short chains of spores on substrate hyphae. Sclerotia-, pycnidia-, sporangia-, and synnemata-like structures are produced by some strains.

Genomics[edit]

The complete genome of "S. coelicolor strain A3(2)" was published in 2002.[11] At the time, the "S. coelicolor" genome was thought to contain the largest number of genes of any bacterium.[11] The chromosome is 8,667,507 bp long with a GC-content of 72.1%, and is predicted to contain 7,825 protein-encoding genes.[11] In terms of taxonomy, "S. coelicolor A3(2)" belongs to the species S. violaceoruber, and is not a validly described separate species; "S. coelicolor A3(2)" is not to be mistaken for the actual S. coelicolor (Müller), although it is often referred to as S. coelicolor for convenience.[12]

The first complete genome sequence of S. avermitilis was completed in 2003.[13] Each of these genomes forms a chromosome with a linear structure, unlike most bacterial genomes, which exist in the form of circular chromosomes.[14] 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. At 10.1 Mbp long and encoding 9,107 provisional genes, it is the largest known Streptomyces genome sequenced, probably due to the large pathogenicity island.[14][15]

Biotechnology[edit]

In recent years, biotechnology researchers have begun using Streptomyces species for heterologous expression of proteins. Traditionally, Escherichia coli was the species of choice to express eukaryotic genes, since it was well understood and easy to work with.[16][17] Expression of eukaryotic proteins in E. coli may be problematic. Sometimes, proteins do not fold properly, which may lead to insolubility, deposition in inclusion bodies, and loss of bioactivity of the product.[18] Though E. coli strains have secretion mechanisms, these are of low efficiency and result in secretion into the periplasmic space, whereas secretion by a Gram-positive bacterium such as a Streptomyces species results in secretion directly into the extracellular medium. In addition, Streptomyces species have more efficient secretion mechanisms than E.coli. The properties of the secretion system is an advantage for industrial production of heterologously expressed protein because it simplifies subsequent purification steps and may increase yield. These properties among others make Streptomyces spp. an attractive alternative to other bacteria such as E. coli and Bacillus subtilis.[18]

Plant pathogenic bacteria[edit]

So far, ten species belonging to this genus have been found to be pathogenic to plants:[6]

  1. S. scabiei
  2. S. acidiscabies
  3. S. europaeiscabiei
  4. S. luridiscabiei
  5. S. niveiscabiei
  6. S. puniciscabiei
  7. S. reticuliscabiei
  8. S. stelliscabiei
  9. S. turgidiscabies (scab disease in potatoes)
  10. S. ipomoeae (soft rot disease in sweet potatoes)

Medicine[edit]

Streptomyces is the largest antibiotic-producing genus, producing antibacterial, antifungal, and antiparasitic drugs, and also a wide range of other bioactive compounds, such as immunosuppressants.[19] Almost all of the bioactive compounds produced by Streptomyces are initiated during the time coinciding with the aerial hyphal formation from the substrate mycelium.[9]

Antifungals[edit]

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

Antibacterials[edit]

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

Clavulanic acid (from S. clavuligerus) is a drug used in combination with some antibiotics (like amoxicillin) to block and/or weaken some bacterial-resistance mechanisms by irreversible beta-lactamase inhibition. Novel antiinfectives currently being developed include Guadinomine (from Streptomyces sp. K01-0509),[28] a compound that blocks the Type III secretion system of Gram-negative bacteria.

Antiparasitic drugs[edit]

S. avermitilis is responsible for the production of one of the most widely employed drugs against nematode and arthropod infestations, ivermectin.

Other[edit]

Less commonly, streptomycetes produce compounds used in other medical treatments: migrastatin (from S. platensis) and bleomycin (from S. verticillus) are antineoplastic (anticancer) drugs.

S. hygroscopicus and S. viridochromeogenes produce the natural herbicide bialaphos.

See also[edit]

References[edit]

  1. ^ Kämpfer P (2006). "The Family Streptomycetaceae, Part I: Taxonomy". In Dworkin, M et al. The prokaryotes: a handbook on the biology of bacteria. Berlin: Springer. pp. 538–604. ISBN 0-387-25493-5. 
  2. ^ Euzéby JP (2008). "Genus Streptomyces". List of Prokaryotic names with Standing in Nomenclature. Retrieved 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. ^ Anderson, AS; Wellington, Elizabeth (2001). "The taxonomy of Streptomyces and related genera". International Journal of Systematic and Evolutionary Microbiology 51 (3): 797–814. doi:10.1099/00207713-51-3-797. 
  6. ^ a b Labeda, D. P. (2010). "Multilocus sequence analysis of phytopathogenic species of the genus Streptomyces". International Journal of Systematic and Evolutionary Microbiology 61 (10): 2525. doi:10.1099/ijs.0.028514-0. 
  7. ^ Zhang, Z.; Wang, Y.; Ruan, J. (1997). "A Proposal to Revive the Genus Kitasatospora (Omura, Takahashi, Iwai, and Tanaka 1982)". International Journal of Systematic Bacteriology 47 (4): 1048–54. doi:10.1099/00207713-47-4-1048. PMID 9336904. 
  8. ^ Kim, Seung Bum; Lonsdale, J; Seong, CN; Goodfellow, M (2003). "Streptacidiphilus gen. Nov., acidophilic actinomycetes with wall chemotype I and emendation of the family Streptomycetaceae (Waksman and Henrici (1943)AL) emend. Rainey et al. 1997". Antonie van Leeuwenhoek 83 (2): 107–16. doi:10.1023/A:1023397724023. PMID 12785304. 
  9. ^ a b c d Chater, Keith (1984). "Morphological and physiological differentiation in Streptomyces". In Losick, Richard. Microbial development. pp. 89–115. doi:10.1101/087969172.16.89. ISBN 978-0-87969-172-1. Retrieved 2012-01-19. 
  10. ^ Dietz, Alma; Mathews, John (1971). "Classification of Streptomyces spore surfaces into five groups". Applied Microbiology 21 (3): 527–533. PMC 377216. PMID 4928607. 
  11. ^ a b c Bentley, S. D.; Chater, K. F.; Cerdeño-Tárraga, A.-M.; Challis, G. L.; Thomson, N. R.; James, K. D.; Harris, D. E.; Quail, M. A.; Kieser, H.; Harper, D.; Bateman, A.; Brown, S.; Chandra, G.; Chen, C. W.; Collins, M.; Cronin, A.; Fraser, A.; Goble, A.; Hidalgo, J.; Hornsby, T.; Howarth, S.; Huang, C.-H.; Kieser, T.; Larke, L.; Murphy, L.; Oliver, K.; O'Neil, S.; Rabbinowitsch, E.; Rajandream, M.-A.; Rutherford, K. (2002). "Complete genome sequence of the model actinomycete Streptomyces coelicolor A3(2)". Nature 417 (6885): 141–147. doi:10.1038/417141a. PMID 12000953. 
  12. ^ Chater, Keith F.; Biró, Sandor; Lee, Kye Joon; Palmer, Tracy; Schrempf, Hildgund (2010). "The complex extracellular biology ofStreptomyces". FEMS Microbiology Reviews 34 (2): 171–98. doi:10.1111/j.1574-6976.2009.00206.x. PMID 20088961. 
  13. ^ 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 (5): 526–531. doi:10.1038/nbt820. PMID 12692562. 
  14. ^ a b Paul Dyson (1 January 2011). Streptomyces: Molecular Biology and Biotechnology. Horizon Scientific Press. p. 5. ISBN 978-1-904455-77-6. Retrieved 16 January 2012. 
  15. ^ "Streptomyces scabies". Sanger Institute. Retrieved 2001-02-26. 
  16. ^ 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. 
  17. ^ 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. 
  18. ^ 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. 
  19. ^ 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. 
  20. ^ Akagawa, H.; Okanishi, M.; Umezawa, H. (1975). "A Plasmid Involved in Chloramphenicol Production in Streptomyces venezuelae: Evidence from Genetic Mapping". Journal of General Microbiology 90 (2): 336–46. doi:10.1099/00221287-90-2-336. PMID 1194895. 
  21. ^ Miao, V. (2005). "Daptomycin biosynthesis in Streptomyces roseosporus: Cloning and analysis of the gene cluster and revision of peptide stereochemistry". Microbiology 151 (5): 1507. doi:10.1099/mic.0.27757-0. 
  22. ^ Woodyer RD, Shao Z, Thomas PM, et al. (November 2006). "Heterologous production of fosfomycin and identification of the minimal biosynthetic gene cluster". Chemistry & biology 13 (11): 1171–82. doi:10.1016/j.chembiol.2006.09.007. PMID 17113999. 
  23. ^ Peschke, Ursula; Schmidt, Heike; Zhang, Hui-Zhan; Piepersberg, Wolfgang (1995). "Molecular characterization of the lincomycin-production gene cluster of Streptomyces lincolnensis 78-11". Molecular Microbiology 16 (6): 1137–56. doi:10.1111/j.1365-2958.1995.tb02338.x. PMID 8577249. 
  24. ^ Howard T. Dulmage (March 1953). "The Production of Neomycin by Streptomyces fradiae in Synthetic Media". Applied Microbiology 1 (2): 103–106. PMC 1056872. PMID 13031516. 
  25. ^ L. Sankaran and Burton M. Pogell (1975-12-01). "Biosynthesis of Puromycin in Streptomyces alboniger: Regulation and Properties of O-Demethylpuromycin O-Methyltransferase". Antimicrobial Agents and Chemotherapy 8 (6): 721–32. doi:10.1128/AAC.8.6.721. PMC 429454. PMID 1211926. Retrieved 2012-01-19. 
  26. ^ Distler, Jürgen; Ebert, Andrea; Mansouri, Kambiz; Pissowotzki, Klaus; Stockmann, Michael; Piepersberg, Wolfgang (1987). "Gene cluster for streptomycin biosynthesis inStreptomyces griseus: Nucleotide sequence of three genes and analysis of transcriptional activity". Nucleic Acids Research 15 (19): 8041–56. doi:10.1093/nar/15.19.8041. PMC 306325. PMID 3118332. 
  27. ^ Dr. Mark Nelson; Robert A. Greenwald; Wolfgang Hillen; Mark L. Nelson (2001). Tetracyclines in biology, chemistry and medicine. Birkhäuser. pp. 8–. ISBN 978-3-7643-6282-9. Retrieved 17 January 2012. 
  28. ^ Holmes, TC; May, AE; Zaleta-Rivera, K; Ruby, JG; Skewes-Cox, P; Fischbach, MA; Derisi, JL; Iwatsuki, M; Ōmura, S; Khosla, C (2012). "Molecular insights into the biosynthesis of guadinomine: A type III secretion system inhibitor". Journal of the American Chemical Society 134 (42): 17797–806. doi:10.1021/ja308622d. PMC 3483642. PMID 23030602. 

Further reading[edit]

External links[edit]