title: A Mycobacterium marinum zone of inhibition assay as a method for screening potential antimycobacterial compounds from marine extracts.
abstract: A novel screening method for antimycobacterial agents using Mycobacterium marinum was developed. M. marinum was selected as a model organism because it has a close phylogenetic relationship to M. tuberculosis, a relatively rapid doubling time, similar drug susceptibilities to M. tuberculosis, and less stringent safety requirements. More than 1000 crude marine and plant extracts were screened against M. marinum in a Zone of Inhibition (ZOI) assay, and twenty-one target extracts were identified. The crude organic extract of the marine sponge, Haliclona sp.10, was chosen for further investigation as it yielded a ZOI of 20 mm at a concentration of 80 microg/disk. Following bioassay-guided fractionation, (-)-papuamine was isolated, and yielded a 15 mm ZOI at a concentration of 25 microg/disk. In standard assays using M. marinum, (-)-papuamine exhibited both an MIC and an MBC95 of 6.25 microg/mL. This is the first report of antimycobacterial activity for (-)-papuamine. In addition, when (-)-papuamine and other natural product extracts were tested for activity against both M. marinum and M. tuberculosis, activity was comparable between the two species. These data indicate that (-)-papuamine is a promising lead for the development of new antimycobacterial agents and that M. marinum is a useful surrogate for the screening of antimycobacterial compounds.
authors.affiliation: University of Minnesota Medical School, Department of Anatomy Microbiology and Pathology, Duluth, MN, USA.
authors.forename: Lucia P
authors.initials: LP
authors.lastname: Barker
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Lien
authors.forename: Olivier S
authors.initials: OS
authors.lastname: Brun
authors.forename: Damen D
authors.initials: DD
authors.lastname: Schaak
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: McDonough
authors.forename: Leng Chee
authors.initials: LC
authors.lastname: Chang
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D008826:Microbial Sensitivity Tests; D019910:Mycobacterium marinum / Q000187:drug effects*; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D010946:Plants, Medicinal; D015203:Reproducibility of Results; D012623:Seawater
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts