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Streptomyces
Streptomyces is a genus of gram-positive endospore-forming
soil bacteria. Many species have been identified with some being pathogenic.
This genus is responsible for producing a majority of the anti-bacterial agents
of practical value. Members of the genus occasionally occur in parasitic forms
on plants and animals.
Streptomyces have a very complex life cycle which consists of two phases:
vegetative growth and reproductive growth. They initiate the reproductive growth
stage by the formation of aerial mycelium which gives the colony the white and
fluffy appearance. Upon spore formation, colonies turn gray because of the
production of gray spore pigment.2 The vegetative mycelium consists
of a network of branched hyphae. For propagation, these bacteria rely on the
formation of spores. In addition, they produce a wide range of secondary
metabolites, or substances with diverse biological activities, some of which are
of great practical value.
Members of the genus Streptomyces are also involved in the degradation of
complex biopolymers such as lignin, melanins, and humic
substances.3
Each Streptomyces is capable of synthesizing more than one biologically
active secondary metabolite. These metabolites can interact with a large number
of biological targets such as yet unidentified proteins of various organelles,
DNA, RNA, and individual proteins. It is, therefore, not surprising that
Streptomyces antibiotics, antifungals, citostatics, immunosuppressants,
anticholesterolemics, antiparasitics, coccidiostatics, animal growth promoters
and natural insecticides are in commercial use. 75% of all antibiotics important
in human and veterinary medicine are produced by Streptomyces
species4, including:
- Streptomyces antibioticus - Used for the production of oleandomycin
antibiotic.
- Streptomyces aureofaciens - Used for the production of
chlortetracycline antibiotic.
- Streptomyces coelicolor - Used in the production of a number of
important antibiotics.
- Streptomyces griseus - Used for the production of streptomycin,
grisein, and candicidin antibiotics.
- Streptomyces lividans - Used for the production of commercial
antibiotics and as a host for gene cloning.
- Streptomyces lincolnensis - Used for the production of lincomycin
antibiotic.
- Streptomyces fradiae - Used for the production of tylosin antibiotic.
- Streptomyces mediterranei - Used for the production of rifampin
antibiotic.
- Streptomyces nodosus - Used for the production of amphotericin
antibiotic.
- Streptomyces cinnamonensis - Used for the production of monensin
antibiotic.
References:
1. MeSH
2. Handbook of copper pharmacology and toxicology By Edward J. Massaro
3. Soil Heavy Metals by Irena Sherameti, Ajit Varma
4. Essays in bioinformatics, Volume 368 By David S. Moss, Sibila Jelaska, Sándor Pongor, NATO Public Diplomacy Division
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