title: Recombinant environmental libraries provide access to microbial diversity for drug discovery from natural products.
abstract: To further explore possible avenues for accessing microbial biodiversity for drug discovery from natural products, we constructed and screened a 5,000-clone "shotgun" environmental DNA library by using an Escherichia coli-Streptomyces lividans shuttle cosmid vector and DNA inserts from microbes derived directly (without cultivation) from soil. The library was analyzed by several means to assess diversity, genetic content, and expression of heterologous genes in both expression hosts. We found that the phylogenetic content of the DNA library was extremely diverse, representing mostly microorganisms that have not been described previously. The library was screened by PCR for sequences similar to parts of type I polyketide synthase genes and tested for the expression of new molecules by screening of live colonies and cell extracts. The results revealed new polyketide synthase genes in at least eight clones. In addition, at least five additional clones were confirmed by high-pressure liquid chromatography analysis and/or biological activity to produce heterologous molecules. These data reinforce the idea that exploiting previously unknown or uncultivated microorganisms for the discovery of novel natural products has potential value and, most importantly, suggest a strategy for developing this technology into a realistic and effective drug discovery tool.
authors.affiliation: Laboratoire d'Ecologie Microbienne du Sol, UMR CNRS 5557, Université Claude Bernard Lyon 1, 69622 Villeurbanne Cedex, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Courtois
authors.forename: Carmela M
authors.initials: CM
authors.lastname: Cappellano
authors.forename: Maria
authors.initials: M
authors.lastname: Ball
authors.forename: Francois-Xavier
authors.initials: FX
authors.lastname: Francou
authors.forename: Philippe
authors.initials: P
authors.lastname: Normand
authors.forename: Gérard
authors.initials: G
authors.lastname: Helynck
authors.forename: Asuncion
authors.initials: A
authors.lastname: Martinez
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Kolvek
authors.forename: Joern
authors.initials: J
authors.lastname: Hopke
authors.forename: Marcia S
authors.initials: MS
authors.lastname: Osburne
authors.forename: Paul R
authors.initials: PR
authors.lastname: August
authors.forename: Renaud
authors.initials: R
authors.lastname: Nalin
authors.forename: Michel
authors.initials: M
authors.lastname: Guérineau
authors.forename: Pascale
authors.initials: P
authors.lastname: Jeannin
authors.forename: Pascal
authors.initials: P
authors.lastname: Simonet
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Pernodet
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000378:metabolism; D001688:Biological Products / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D003360:Cosmids; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D015723:Gene Library; D014644:Genetic Variation; D005822:Genetic Vectors; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D012988:Soil Microbiology; D013302:Streptomyces / Q000235:genetics; D014169:Transformation, Bacterial
chemical_list: D000900:Anti-Bacterial Agents; D001688:Biological Products; D004269:DNA, Bacterial; D009097:Multienzyme Complexes