Streptomyces isolates have yielded the majority of human, animal, and agricultural antibiotics, as well as a number of fundamental chemotherapy medicines. Streptomyces is the largest antibiotic-producing genus of actinobacteria, producing chemotherapy, antibacterial, antifungal, antiparasitic drugs, and immunosuppressants. Streptomyces isolates are typically initiated with the aerial hyphal formation from the mycelium.
Most clinical antibiotics were found during the "golden age of antibiotics". Actinomycin was the first antibiotic isolated from Streptomyces in 1940, followed by streptomycin three years later. Streptomycetes isolates would go on to comprise over two-thirds of all marketed antibiotics. Streptomyces antibiotics include: Clavulanic acid is used in combination with some antibiotics to weaken bacterial-resistance. Novel antiinfectives being developed include Guadinomine, an inhibitor of the type III secretion system. Non-Streptomycesactinomycetes, filamentous fungi, and non-filamentous bacteria, have also yielded important antibiotics.
Traditionally, Escherichia coli is the choice bacterium to express eukaryotic and recombinant genes. E. coli is well understood and has a successfultrack record producing insulin, the artemisinin precursor artemisinic acid, and filgrastim. However, use of E. coli has limitations including misfolding of eukaryotic proteins, insolubility issues, deposition in inclusion bodies, low secretion efficiency, secretion to periplasmic space. Streptomyces offers potential advantages including superior secretion mechanisms, higher yields, a simpler end-product purification process, making Streptomyces an attractive alternative to E. coli and Bacillus subtilis. Streptomyces coelicolor, Streptomyces avermitilis, Streptomyces griseus, and Saccharopolyspora erythraea, are capable of secondary metaboliteproduction. Streptomyces coelicolor has shown useful for the heterologous expression of proteins. Methods like "ribosome engineering" have been used to achieve 180-fold higher yields with S. coelicolor.
Other
StreptomeDB, a directory of Streptomyces isolates, contains over 2400 compounds isolated from more than 1900 strains. Streptomyces hygroscopicus and Streptomyces viridochromeogenes produce the herbicide bialaphos. Expansion of Streptomyces screenings have included endophytes, extremophiles, and marine varieties. A recent screening of TCMextracts revealed a Streptomyces that produces a number of antitubercular pluramycins.
