PICTURES OF STREPTOMYCETES

ANTIBIOTICS PRODUCED BY STREPTOMYCETES

Some examples produced by Streptomycetes and the related actinomycetes are described as below. Represented as antimicrobial compound against tuberculosis are streptomycin (Streptomyces griseus), rifamycin (Amycolatopsis mediterranei), erythromycin (Saccharopolyspora erythraea), and oleandomycin (Streptomyces antibioticus). There are more bioactive compounds such as avermectin (Streptomyces avermitilis), bleomycin (Streptomyces verticillus) and daunomycin (Streptomyces peuceticus) as antitumor compounds, FK506 (Streptomyces tsukubaensis) as an immunosuppressant, and validamycin (Stereptomyces hygroscopicus var. limoneus) as a treatment of rice sheath blight disease.

COMPLEX LIFE CYCLE OF STREPTOMYCES

A spore germinates with spreading the filaments into such a solid medium ("vegetative mycelium", step 0-2). Then the developed vegetative mycelium form sporophores vertically toward the surface ("aerial mycelium", step 3-4). The aerial mycelium spirals (step 5), and then the polynycleated aerial filaments are partitioned (step 6). The resulting sheaths will become spores (step 7), and the another cycle continues. The secondary metabolites including antibiotics are secreted during the generation of aerial hyphae from the vegetative mycelium.

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