title: Metabolic perturbation to enhance polyketide and nonribosomal peptide antibiotic production using triclosan and ribosome-targeting drugs.
abstract: Although transcriptional activation of pathwayspecific positive regulatory genes and/or biosynthetic genes is primarily important for enhancing secondary metabolite production, reinforcement of substrate supply, as represented by primary metabolites, is also effective. For example, partial inhibition of fatty acid synthesis with ARC2 (an analog of triclosan) was found to enhance polyketide antibiotic production. Here, we demonstrate that this approach is effective even for industrial high-producing strains, for example enhancing salinomycin production by 40%, reaching 30.4 g/l of salinomycin in an industrial Streptomyces albus strain. We also hypothesized that a similar approach would be applicable to another important antibiotic group, nonribosomal peptide (NRP) antibiotics. We therefore attempted to partially inhibit protein synthesis by using ribosome-targeting drugs at subinhibitory concentrations (1/50∼1/2 of MICs), which may result in the preferential recruitment of intracellular amino acids to the biosynthesis of NRP antibiotics rather than to protein synthesis. Among the ribosome-targeting drugs examined, chloramphenicol at subinhibitory concentrations was most effective at enhancing the production by Streptomyces of NRP antibiotics such as actinomycin, calcium-dependent antibiotic (CDA), and piperidamycin, often resulting in an almost 2-fold increase in antibiotic production. Chloramphenicol activated biosynthetic genes at the transcriptional level and increased amino acid pool sizes 1.5- to 6-fold, enhancing the production of actinomycin and CDA. This "metabolic perturbation" approach using subinhibitory concentrations of ribosome-targeting drugs is a rational method of enhancing NRP antibiotic production, being especially effective in transcriptionally activated (e.g., rpoB mutant) strains. Because this approach does not require prior genetic information, it may be widely applicable for enhancing bacterial production of NRP antibiotics and bioactive peptides.
authors.affiliation: Department of Life Sciences, Hiroshima Institute of Technology, Saeki-ku, Hiroshima, 731-5193, Japan.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Department of Life Sciences, Hiroshima Institute of Technology, Saeki-ku, Hiroshima, 731-5193, Japan.
authors.forename: Masumi
authors.initials: M
authors.lastname: Izawa
authors.affiliation: Department of Life Sciences, Hiroshima Institute of Technology, Saeki-ku, Hiroshima, 731-5193, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Hiraga
authors.affiliation: Department of Life Sciences, Hiroshima Institute of Technology, Saeki-ku, Hiroshima, 731-5193, Japan.
authors.forename: Yuya
authors.initials: Y
authors.lastname: Misaki
authors.affiliation: Department of Life Sciences, Hiroshima Institute of Technology, Saeki-ku, Hiroshima, 731-5193, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Department of Life Sciences, Hiroshima Institute of Technology, Saeki-ku, Hiroshima, 731-5193, Japan. k.ochi.bz@it-hiroshima.ac.jp.
authors.forename: Kozo
authors.initials: K
authors.lastname: Ochi
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002701:Chloramphenicol / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial; D007218:Industrial Microbiology / Q000379:methods*; D008034:Lincomycin / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D046908:Peptide Biosynthesis, Nucleic Acid-Independent; D010455:Peptides / Q000737:chemistry; D061065:Polyketides / Q000378:metabolism*; D011714:Pyrans / Q000378:metabolism; D012270:Ribosomes / Q000187:drug effects / Q000378:metabolism; D013302:Streptomyces / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D014260:Triclosan / Q000494:pharmacology*; D000095662:Polyether Polyketides
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002701:Chloramphenicol; D008034:Lincomycin; D010455:Peptides; D061065:Polyketides; D011714:Pyrans; D014260:Triclosan; C010327:salinomycin; D000095662:Polyether Polyketides
keywords: Chloramphenicol; Lincomycin; Metabolic perturbation; Nonribosomal peptides; Polyketides; Streptomyces; Triclosan