title: Discovery of novel cell wall-active compounds using P ywaC, a sensitive reporter of cell wall stress, in the model gram-positive bacterium Bacillus subtilis.
abstract: The emergence of antibiotic resistance in recent years has radically reduced the clinical efficacy of many antibacterial treatments and now poses a significant threat to public health. One of the earliest studied well-validated targets for antimicrobial discovery is the bacterial cell wall. The essential nature of this pathway, its conservation among bacterial pathogens, and its absence in human biology have made cell wall synthesis an attractive pathway for new antibiotic drug discovery. Herein, we describe a highly sensitive screening methodology for identifying chemical agents that perturb cell wall synthesis, using the model of the Gram-positive bacterium Bacillus subtilis. We report on a cell-based pilot screen of 26,000 small molecules to look for cell wall-active chemicals in real time using an autonomous luminescence gene cluster driven by the promoter of ywaC, which encodes a guanosine tetra(penta)phosphate synthetase that is expressed under cell wall stress. The promoter-reporter system was generally much more sensitive than growth inhibition testing and responded almost exclusively to cell wall-active antibiotics. Follow-up testing of the compounds from the pilot screen with secondary assays to verify the mechanism of action led to the discovery of 9 novel cell wall-active compounds.
authors.affiliation: Department of Biochemistry and Biomedical Sciences and Michael G. DeGroote Institute of Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada.
authors.forename: T L
authors.initials: TL
authors.lastname: Czarny
authors.affiliation: Department of Biochemistry and Biomedical Sciences and Michael G. DeGroote Institute of Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada.
authors.forename: A L
authors.initials: AL
authors.lastname: Perri
authors.affiliation: Department of Biochemistry and Biomedical Sciences and Michael G. DeGroote Institute of Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada.
authors.forename: S
authors.initials: S
authors.lastname: French
authors.affiliation: Department of Biochemistry and Biomedical Sciences and Michael G. DeGroote Institute of Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada ebrown@mcmaster.ca.
authors.forename: E D
authors.initials: ED
authors.lastname: Brown
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects* / Q000235:genetics*; D002462:Cell Membrane / Q000187:drug effects; D002473:Cell Wall / Q000187:drug effects* / Q000235:genetics*; D004305:Dose-Response Relationship, Drug; D005798:Genes, Bacterial / Q000187:drug effects* / Q000235:genetics*; D017930:Genes, Reporter / Q000187:drug effects* / Q000235:genetics*; D057166:High-Throughput Screening Assays; D008025:Ligases / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D010539:Permeability / Q000187:drug effects; D054852:Small Molecule Libraries; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D054852:Small Molecule Libraries; C100969:guanosine pentaphosphate synthetase; D008025:Ligases