title: Genetic manipulation of polyphosphate metabolism affects cadmium tolerance in Escherichia coli.
abstract: The polyphosphate metabolic pathways in Escherichia coli were genetically manipulated to test the effect of polyphosphate on tolerance to cadmium. A polyphosphate kinase (ppk) and polyphosphatase (ppx) mutant strain produced no polyphosphate, whereas the same strain carrying multiple copies of ppk on a high-copy plasmid produced significant quantities. The doubling times of both strains increased with increasing cadmium concentrations. In contrast, the mutant strain carrying multiple copies of ppk and ppx produced 1/20 of the polyphosphate found in the strain carrying multiple copies of ppk only and showed no significant increase in doubling time over the same cadmium concentration range.
authors.affiliation: Department of Chemical Engineering, University of California, Berkeley 94720-1462, USA. keasling@garnet.berkeley.edu
authors.forename: J D
authors.initials: JD
authors.lastname: Keasling
authors.forename: G A
authors.initials: GA
authors.lastname: Hupf
mesh_terms: D017766:Acid Anhydride Hydrolases / Q000235:genetics; D002104:Cadmium / Q000494:pharmacology*; D004352:Drug Resistance, Microbial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D005798:Genes, Bacterial; D009154:Mutation; D017856:Phosphotransferases (Phosphate Group Acceptor) / Q000235:genetics; D011122:Polyphosphates / Q000378:metabolism*
chemical_list: D011122:Polyphosphates; D002104:Cadmium; D017856:Phosphotransferases (Phosphate Group Acceptor); C022424:polyphosphate kinase; D017766:Acid Anhydride Hydrolases; C022563:endopolyphosphatase