Streptomyces

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Streptomyces
Streptomyces griseus color enhanced scanning electron micrograph..jpg
S. griseus - a species of Streptomyces genus
Scientific classification
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Streptomyces

Waksman & Henrici 1943

Streptomyces is the largest genus of Actinobacteria, Gram-positive bacteria[1]. Streptomyces is often found in soil and is very much similar to fungi by its shape. They form long thin threads called hyphae that can differentiate into a chain of spores for reproduction[2]. Almost all of the bioactive compounds produced by Streptomyces are made while the hyphae are forming from the substrate mycelium[3].

Use in medicine and science[change | change source]

Streptomyces are medically important, as they produce antifungals, antiparasitic drugs, antivirals, antitumorals, anti-hypertensives, immunosuppressants and antibiotics[4][5]. Different species of streptomyces are used to produce different antibiotics. Over 500 species of Streptomyces bacteria have been described[6]. For example, widely studied S. griseus was the first to be used in production of an antibiotic streptomycin, while S. avermitilis as a source of avermictin[7]. Another well-studied species, S coelicolor, is widely used in genetic studies[8]. Overall, Streptomyces produce over two-thirds of the clinically useful antibiotics of natural origin, such as tetracycline, neomycin and chloramphenicol[9][10].

Slide culture of a Streptomyces species

Antibiotic mechanism[change | change source]

Antibiotics target essential proteins for pathogens’ growth and survival, inhibiting essential functions. For example, streptomycin, which is made from S. griseus, irreversibly binds to bacterial genetic material and causes errors in the production of new proteins, which leads to cell death[11]. It can be used for treating severe infections, such as tuberculosis and plague[12]. Another example is avermectin, made from S. avermitili. It causes invertebrate paralysis (inability to make and pass nerve impulses), which is used as a drug and pesticide against parasitic worms and insects. Avermectin enhances glutamate (neurotransmitter) at the glutamate-gated chloride channels that mammals don’t possess. It causes the excess of chloride ions inside the cell (hyperpolarisation), so the action potential cannot be further induced, ultimately leading to paralysis[13].

Antibiotic resistance[change | change source]

Genetic changes in bacteria might result in antibiotic resistance. They might be acquired through spontaneous mutations (vertical gene transfer) or through other bacteria passing their genes (horizontal gene transfer). Self-medications or improper medication use can result in the emergence of resistant bacteria. It is difficult to obtain new antibiotics, that is why researchers seek to improve existing ones[14], as well as working to discover new drugs.

References[change | change source]

  1. Kämpfer P.; et al. (2006). "The Family Streptomycetaceae, Part I: Taxonomy". In Dworkin M. (ed.). The prokaryotes: a handbook on the biology of bacteria. Berlin: Springer. pp. 538–604. ISBN 0-387-25493-5.
  2. de Lima Procópio, Rudi Emerson; da Silva, Ingrid Reis; Martins, Mayra Kassawara; de Azevedo, João Lúcio; de Araújo, Janete Magali (2012-09-01). "Antibiotics produced by Streptomyces". The Brazilian Journal of Infectious Diseases. 16 (5): 466–471. doi:10.1016/j.bjid.2012.08.014. ISSN 1413-8670.
  3. Chater, Keith F. et al 2010. The complex extracellular biology of Streptomyces. FEMS Microbiology Reviews 34 (2): 171–98. [1]
  4. Ōmura, Satoshi; Ikeda, Haruo; Ishikawa, Jun; Hanamoto, Akiharu; Takahashi, Chigusa; Shinose, Mayumi; Takahashi, Yoko; Horikawa, Hiroshi; Nakazawa, Hidekazu; Osonoe, Tomomi; Kikuchi, Hisashi (2001-10-09). "Genome sequence of an industrial microorganism Streptomyces avermitilis : Deducing the ability of producing secondary metabolites". Proceedings of the National Academy of Sciences. 98 (21): 12215–12220. doi:10.1073/pnas.211433198. ISSN 0027-8424. PMC 59794. PMID 11572948.{{cite journal}}: CS1 maint: PMC format (link)
  5. Watve M.G.; et al. (2001). "How many antibiotics are produced by the genus Streptomyces?". Arch. Microbiol. 176 (5): 386–90. doi:10.1007/s002030100345. PMID 11702082. S2CID 603765.
  6. Euzéby J.P. (2008). "Genus Streptomyces". List of prokaryotic names with standing in nomenclature. Archived from the original on 2012-12-25. Retrieved 2008-09-28.
  7. Ohnishi, Yasuo; Ishikawa, Jun; Hara, Hirofumi; Suzuki, Hirokazu; Ikenoya, Miwa; Ikeda, Haruo; Yamashita, Atsushi; Hattori, Masahira; Horinouchi, Sueharu (2008-06). "Genome Sequence of the Streptomycin-Producing Microorganism Streptomyces griseus IFO 13350". Journal of Bacteriology. 190 (11): 4050–4060. doi:10.1128/JB.00204-08. ISSN 0021-9193. PMC 2395044. PMID 18375553. {{cite journal}}: Check date values in: |date= (help)CS1 maint: PMC format (link)
  8. 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. (2002-05). "Complete genome sequence of the model actinomycete Streptomyces coelicolor A3(2)". Nature. 417 (6885): 141–147. doi:10.1038/417141a. ISSN 1476-4687. {{cite journal}}: Check date values in: |date= (help)
  9. Watve, Milind G.; Tickoo, Rashmi; Jog, Maithili M.; Bhole, Bhalachandra D. (2001-11-01). "How many antibiotics are produced by the genus Streptomyces?". Archives of Microbiology. 176 (5): 386–390. doi:10.1007/s002030100345. ISSN 1432-072X.
  10. Kieser T.; et al. (2000). Practical Streptomyces genetics (2nd ed.). Norwich, England: John Innes Foundation. ISBN 0-7084-0623-8.
  11. PubChem. "Streptomycin". pubchem.ncbi.nlm.nih.gov. Retrieved 2022-07-24.
  12. "Streptomycin Monograph for Professionals". Drugs.com. Retrieved 2022-07-24.
  13. Bloomquist, Jeffrey R. (1993-10-01). "Toxicology, mode of action and target site-mediated resistance to insecticides acting on chloride channels". Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology. 106 (2): 301–314. doi:10.1016/0742-8413(93)90138-B. ISSN 0742-8413.
  14. Fischbach, Michael A.; Walsh, Christopher T. (2009-08-28). "Antibiotics for Emerging Pathogens". Science. 325 (5944): 1089–1093. doi:10.1126/science.1176667. ISSN 0036-8075. PMC 2802854. PMID 19713519.{{cite journal}}: CS1 maint: PMC format (link)