title: Thallous ion is accumulated by potassium transport systems in Escherichia coli.
abstract: The accumulation of 204T1+ by Escherichia coli occurs primarily via either of two K+ transport systems called Kdp and TrkA. T1+ influx is inhibited and T1+ efflux is stimulated by the addition of K+ to the assay medium. Mutants defective in both the Kdp and TrkA systems accumulate little T1+. Uptake of triphenylmethylphosphonium, a lipid-soluble cation whose distribution is widely used to estimate the membrane electrical potential in bacteria, occurs to about the same extent in mutants that accumulate little T1+ as in strains that accumulate T1+ to high levels. These findings indicate that T1+ may be useful as a probe of bacterial K+ transport systems but is not a reliable indicator of the membrane electrical potential in E. coli.
mesh_terms: D001693:Biological Transport, Active / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D005838:Genotype; D007700:Kinetics; D011188:Potassium / Q000378:metabolism* / Q000494:pharmacology; D013045:Species Specificity; D013793:Thallium / Q000378:metabolism*
chemical_list: D013793:Thallium; D011188:Potassium