title: The initial structural lesion of penicillin action in Bacillus megaterium.
abstract: The effect of penicillin on the structure of Bacillus megaterium cells was followed in media with and without osmotic stabilization. In peptone without osmotic support the cells showed a distortion of the normal membrane-wall relationship by 20 minutes. This appeared to be a combination of both membrane distortion and cytoplasmic leakage. Lytic changes quickly followed. With osmotic support a clean-cut lesion at the transverse-septal site developed by 10 minutes' growth in penicillin. The membrane lost its normal relationship to the cell wall and formed a pocket which was filled with a fibrous material which appeared to be unorganized wall mucopeptide. The pocket of fibers enlarged until the cell either lysed or formed a protoplast.
mesh_terms: D001410:Bacillus megaterium / Q000187:drug effects*; D003585:Cell Biology; D002462:Cell Membrane / Q000187:drug effects; D003470:Culture Media; D066298:In Vitro Techniques; D008712:Methicillin / Q000494:pharmacology*; D008854:Microscopy, Electron; D009995:Osmosis
chemical_list: D003470:Culture Media; D008712:Methicillin