title: Implication of PKS type I gene and chromatographic strategy for the biodiscovery of antimicrobial polyketide metabolites from endosymbiotic Nocardiopsis prasina CLA68.
abstract: Advanced approach in probing for polyketide antimicrobials requires novel genomics and chromatographic strategies. An endophytic strain CLA68 was isolated from the root of Combretum latifolium Blume (Combretaceae) collected from the Western Ghats of Southern India. Strain CLA68 was then identified as Nocardiopsis prasina by its characteristic culture morphology and analysis of 16S rRNA gene sequence. Biosynthetic polyketide synthase genes were investigated using two pairs of degenerate primers. Ethyl acetate extract of CLA68 exhibited broad spectrum activity against a panel of test human pathogens. PKS type-I gene detection and chromatographic strategy yielded a robust polyketide antimicrobial compound which identified as nocapyrone E. Minimum inhibitory concentration of the purified compound against MRSA and other human pathogens ranged between 25 and 100 μg/ml. The present work highlights the utility of N. prasina CLA68 as potential source for antimicrobial polyketide nocapyrone E which could help to combat multidrug-resistant pathogens. This study demonstrates feasibility of PKS type-I gene-based molecular approach and chemical investigation by chromatographic approach is the best method for prediction and rapid discovery of novel polyketides from endosymbiotic actinomycetes. The sequence data of this endosymbiotic actinomycete is deposited in GenBank under the accession no. KP269077.
authors.affiliation: Microbial Drugs Laboratory, Department of Studies in Microbiology, Manasagangotri, University of Mysore, Mysore, 570 006, Karnataka, India.
authors.forename: H C Yashavantha
authors.initials: HC
authors.lastname: Rao
authors.affiliation: Microbial Drugs Laboratory, Department of Studies in Microbiology, Manasagangotri, University of Mysore, Mysore, 570 006, Karnataka, India.
authors.forename: Devaraju
authors.initials: D
authors.lastname: Rakshith
authors.affiliation: Post Graduate Department of Chemistry, Sarada Vilas College, Mysore, 570 004, Karnataka, India.
authors.forename: D M
authors.initials: DM
authors.lastname: Gurudatt
authors.affiliation: Microbial Drugs Laboratory, Department of Studies in Microbiology, Manasagangotri, University of Mysore, Mysore, 570 006, Karnataka, India. satish.micro@gmail.com.
authors.forename: Sreedharamurthy
authors.initials: S
authors.lastname: Satish
mesh_terms: D039903:Actinobacteria / Q000201:enzymology* / Q000378:metabolism; D000890:Anti-Infective Agents / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism; D001419:Bacteria / Q000187:drug effects; D002845:Chromatography; D055808:Drug Discovery; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D048630:Polyketide Synthases / Q000235:genetics*; D061065:Polyketides / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D061065:Polyketides; D048630:Polyketide Synthases
keywords: Antimicrobial metabolites; Bioautography; Biodiscovery; Endosymbionts; Nocardiopsis prasina; Polyketide synthase gene