title: Toxic waste disposal in Escherichia coli.
abstract: About 10% of the nalidixic acid-resistant (Nal(r)) mutants in a transposition-induced library exhibited a growth factor requirement as the result of cysH, icdA, metE, or purB mutation. Resistance in all of these mutants required a functional AcrAB-TolC efflux pump, but the EmrAB-TolC pump played no obvious role. Transcription of acrAB was increased in each type of Nal(r) mutant. In the icdA and purB mutants, each of the known signaling pathways appeared to be used in activating the AcrAB-TolC pump. The metabolites that accumulate upstream of the blocks caused by the mutations are hypothesized to increase the levels of the AcrAB-TolC pump, thereby removing nalidixic acid from the organism.
authors.affiliation: Department of Biology, University of Michigan, Ann Arbor, Michigan 48109-1048, USA. helling@umich.edu
authors.forename: Robert B
authors.initials: RB
authors.lastname: Helling
authors.forename: Brian K
authors.initials: BK
authors.lastname: Janes
authors.forename: Heather
authors.initials: H
authors.lastname: Kimball
authors.forename: Timothy
authors.initials: T
authors.lastname: Tran
authors.forename: Michael
authors.initials: M
authors.lastname: Bundesmann
authors.forename: Pietra
authors.initials: P
authors.lastname: Check
authors.forename: Darcy
authors.initials: D
authors.lastname: Phelan
authors.forename: Charles
authors.initials: C
authors.lastname: Miller
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins; D004251:DNA Transposable Elements; D004352:Drug Resistance, Microbial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000502:physiology*; D029968:Escherichia coli Proteins; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009154:Mutation; D009268:Nalidixic Acid / Q000633:toxicity; D015238:Sulfotransferases
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004251:DNA Transposable Elements; D029968:Escherichia coli Proteins; D008074:Lipoproteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009268:Nalidixic Acid; D015238:Sulfotransferases; C083497:AcrA protein, E coli; C083496:AcrB protein, E coli; C489681:EmrA protein, E coli; C073126:tolC protein, E coli; C077168:emrA protein, Bacteria; C077169:VceB protein, Vibrio cholerae; C022321:PAPS sulfotransferase