title: Visualization of mycobacterial membrane dynamics in live cells.
abstract: Mycobacteria are endowed with a highly impermeable mycomembrane that confers intrinsic resistance to many antibiotics. Several unique mycomembrane glycolipids have been isolated and structurally characterized, but the underlying organization and dynamics of glycolipids within the cell envelope remain poorly understood. We report here a study of mycomembrane dynamics that was enabled by trehalose-fluorophore conjugates capable of labeling trehalose glycolipids in live actinomycetes. We identified fluorescein-trehalose analogues that are metabolically incorporated into the trehalose mycolates of representative Mycobacterium, Corynebacterium, Nocardia, and Rhodococcus species. Using these probes, we studied the mobilities of labeled glycolipids by time-lapse microscopy and fluorescence recovery after photobleaching experiments and found that mycomembrane fluidity varies widely across species and correlates with mycolic acid structure. Finally, we discovered that treatment of mycobacteria with ethambutol, a front-line tuberculosis (TB) drug, significantly increases mycomembrane fluidity. These findings enhance our understanding of mycobacterial cell envelope structure and dynamics and have implications for development of TB drug cocktails.
authors.affiliation: Department of Chemistry, University of California , Berkeley, California 94720, United States.|Department of Chemistry, Stanford University , Stanford, California 94305, United States.
authors.forename: Frances P
authors.initials: FP
authors.lastname: Rodriguez-Rivera
authors.forename: Xiaoxue
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Howard Hughes Medical Institute , Chevy Chase, Maryland 20815, United States.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Theriot
authors.affiliation: Department of Chemistry, Stanford University , Stanford, California 94305, United States.|Howard Hughes Medical Institute , Chevy Chase, Maryland 20815, United States.
authors.forename: Carolyn R
authors.identifier: 0000-0003-4482-2754
authors.initials: CR
authors.lastname: Bertozzi
mesh_terms: D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D002470:Cell Survival; D004977:Ethambutol / Q000494:pharmacology; D008560:Membrane Fluidity / Q000187:drug effects; D009161:Mycobacterium / Q000166:cytology* / Q000187:drug effects; D013816:Thermodynamics
chemical_list: D004977:Ethambutol