[Relation between the transport of glutamic acid and Escherichia coli resistance to tetracyclines]

The rate of glutamate uptake was shown to decrease while the rate of glutamate export from preloaded cells increased after the resistance to tetracyclines had been induced in the cells of plasmid-bearing Escherichia coli strains. Similar results were obtained with membrane vesicles prepared from the cells induced by the antibiotic and from the non-induced cells. These data imply that the transport channel formed after the induction in the membranes of resistant cells can also function as a mechanism which mediates the active export of glutamate from the cells.