AFM resolves effects of ethambutol on nanomechanics and nanostructures of single dividing mycobacteria in real-time.

Dynamic nanomechanics and nanostructures of dividing and anti-mycobacterial drug treated mycobacterium remain to be fully elucidated. Atomic force microscopy (AFM) is a promising nanotechnology tool for characterization of these dynamic alterations, especially at the single cell level. In this work, single dividing mycobacterium JLS (M.JLS) before and after anti-mycobacterial drug (ethambutol, EMB) treatment was in situ quantitatively analyzed, suggesting that nanomechanics would be referred as a sensitive indicator for evaluating efficacy of anti-mycobacterial drugs. Dynamic evidence on the contractile ring and septal furrow of dividing M.JLS implied that inhibition of contractile ring formation would be a crucial process for EMB to disturb M.JLS division. These results could facilitate further explaining the regulation mechanism of the contractile ring as well as nanomechanical roles of the cell wall in the course of mycobacterial division. This work describe a new way for further elucidating the mechanisms of mycobacterial division and anti-mycobacterial drug action, as well as the drug-resistance developing mechanism of pathogenic mycobacteria.