title: Heavy metal resistance patterns of Frankia strains.
abstract: The sensitivity of 12 Frankia strains to heavy metals was determined by a growth inhibition assay. In general, all of the strains were sensitive to low concentrations (<0.5 mM) of Ag(1+), AsO(2)(1-), Cd(2+), SbO(2)(1-), and Ni(2+), but most of the strains were less sensitive to Pb(2+) (6 to 8 mM), CrO(4)(2-) (1.0 to 1.75 mM), AsO(4)(3-) (>50 mM), and SeO(2)(2-) (1.5 to 3.5 mM). While most strains were sensitive to 0.1 mM Cu(2+), four strains were resistant to elevated levels of Cu(2+) (2 to 5 mM and concentrations as high as 20 mM). The mechanism of SeO(2)(2-) resistance seems to involve reduction of the selenite oxyanion to insoluble elemental selenium, whereas Pb(2+) resistance and Cu(2+) resistance may involve sequestration or binding mechanisms. Indications of the resistance mechanisms for the other heavy metals were not as clear.
authors.affiliation: Department of Microbiology, University of New Hampshire, 46 College Road, Durham, NH 03824-2617, USA.
authors.forename: Joel W
authors.initials: JW
authors.lastname: Richards
authors.forename: Glenn D
authors.initials: GD
authors.lastname: Krumholz
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Chval
authors.forename: Louis S
authors.initials: LS
authors.lastname: Tisa
mesh_terms: D000192:Actinomycetales / Q000145:classification / Q000187:drug effects* / Q000254:growth & development; D003470:Culture Media; D024881:Drug Resistance, Bacterial; D019216:Metals, Heavy / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000379:methods
chemical_list: D003470:Culture Media; D019216:Metals, Heavy