title: Tetracycline-resistant L-forms isolated from an antibiotic-susceptible strain of Listeria monocytogenes.
abstract: A tetracycline-susceptible strain of Listeria monocytogenes type 4b was converted to stable L-forms by penicillin. L-form variants resistant to tetracycline were then selected from a predominantly tetracycline-susceptible L-form population on plates containing penicillin and increasing concentrations of tetracycline. The origin of tetracycline-resistant L-forms from the parent Listeria strain was confirmed biochemically, by immunofluorescence, and by polyacrylamide gel electrophoresis. Scanning and transmission electron microscopy confirmed the typical L-form structure and the complete lack of cell wall in both L-form strains. The level of [3H]tetracycline uptake was lower in tetracycline-resistant than in susceptible cells.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D004352:Drug Resistance, Microbial; D007740:L Forms / Q000187:drug effects*; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000648:ultrastructure; D008826:Microbial Sensitivity Tests; D009154:Mutation; D013752:Tetracycline / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D013752:Tetracycline