Antibiotic Overproduction by rpsL and rsmG Mutants of Various Actinomycetes

Abstract

Certain streptomycin resistance mutations (i.e., rpsL and rsmG) result in the overproduction of antibiotics in various actinomycetes. Moreover, rpsL rsmG double-mutant strains show a further increase in antibiotic production. rpsL but not rsmG mutations result in a marked enhancement of oligomycin production in Streptomyces avermitilis and erythromycin production in Saccharopolyspora erythraea, accompanied by increased transcription of a key developmental regulator gene, bldD, in the latter organism.Recently, we described a practical method of increasing antibiotic production in bacteria by modulating ribosomal components (ribosomal proteins or rRNA), specifically by the introduction of mutations conferring drug resistance (5,22,23). This approach, called "ribosome engineering" (12, 14), has several advantages, including the ability to screen for drug resistance mutations by simple selection on drug-containing plates, even if the mutation frequency is extremely low (e.g.,Ϫ10 ). As demonstrated with Streptomyces coelicolor A3(2) and Streptomyces albus, ⌬rsmG and rpsL(K88E) mutants exhibit enhanced protein synthetic activity during the late growth phase (10,16,21), which is consistent with our hypothesis (4)

Rare earth elements activate the secondary metabolite–biosynthetic gene clusters in Streptomyces coelicolor A3(2)

“…The mechanism of action, however, remains to be clarified. The present method, together with other methods reported recently, 8,9,12,[22][23][24] may be useful for activating silent genes, eventually leading to the discovery of novel biologically active compounds. Figure 3 Comparative metabolic profiling of the culture extracts.…”

“…6 Our laboratory has previously developed a method to increase antibacterial production. [7][8][9] This new approach, called 'ribosome engineering' , 10,11 has several advantages. In this method, bacteria are grown on antibiotics to select antibioticresistant strains.…”

Activation of secondary metabolite–biosynthetic gene clusters by generating rsmG mutations in Streptomyces griseus

“…5,6 Unlike other Streptomyces spp. (MIC to streptomycin, 0.2-2 mg ml À1 ), the streptomycin producer S. griseus IFO13189 showed a relatively high level of resistance (MIC¼70 mg ml À1 ).…”

“…2-4 Recently, we described a practical method for increasing antibiotic production in bacteria by modulating ribosomal components (ribosomal proteins or rRNA), specifically by generating mutations conferring drug resistance, such as streptomycin resistance. [5][6][7] This approach, called 'ribosome engineering' , 8 has several advantages including the ability to screen for drug resistance mutations by simple selection on drug-containing plates, even if the mutation frequency is extremely low (for example, o10 À10 ), and has been shown to be effective for improving the industrial strains, which had been bred to produce large amount of antibiotics. 9,10 S. griseus is a filamentous, soil-living, Gram-positive bacteria, which produces an aminoglycoside antibiotic, streptomycin, and is characterized by the presence of a streptomycin self-resistance gene, aphD, which encodes streptomycin-6-phosphotransferase.…”

Molecular beacons to identify gifted microbes for genome mining

“…Many approaches, including isolation of mutants altered in transcription or translation, genetic manipulation of positive and negative regulation, heterologous expression in specialized hosts and others, have been described. 8,[21][22][23][24][25][26][27][28][29][30] For microbial genome mining to become a robust methodology to drive the discovery of new and novel NPs for drug discovery, it is important to have a set of bioinformatics tools that can predict which microorganisms are the most 'gifted' for SM production. antiSMASH 3.0 31 is particularly useful to identify the numbers and types of SMs encoded by microbes, and has been used to survey a wide range of bacteria and archaea for those microorganisms most gifted for SM production.…”