title: Luminescent investigations of terbium(III) biosorption as a surrogate for heavy metals and radionuclides.
abstract: We describe a metal transport system for investigating the interfacial interactions between the anionic surface charge of a gram-negative bacterium (Escherichia coli) and a trivalent cationic metal, Tb3+. We believe this is the first description of the uptake kinetics, sub- and intracellular distribution, and temporal fate of Tb3+ ion in E. coli. We used the luminescence of the terbium-dipicolinic acid chelate to study metal ion transport. The bacteria had a high tolerance for the metal (IC(50) = 4 mM Tb3+). Metal ion transport was passive and metabolism independent. The uptake kinetics rapidly reached a maximum within 15 min, followed by a stasis for 60 min, and declining thereafter between 120 and 240 min, resulting in a biphasic curve. During this period, greater than one-third of the metal ion was sequestered within the cell. Our choice of a safe Biosafety Level I E. coli bacteria and the relatively non-toxic Tb3+ metal represents a model system for luminescent investigations of biosorption, for studying bacterial-water interfacial chemistry and for the bioremediation of heavy metals and radionuclides.
authors.affiliation: Biosensors and Nanomaterials Department, Sandia National Laboratories, P.O. Box 5800, MS 1425, Albuquerque, NM 87185-1425, USA. kachyut@sandia.gov
authors.forename: Komandoor E
authors.initials: KE
authors.lastname: Achyuthan
authors.forename: Dulce C
authors.initials: DC
authors.lastname: Arango
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Carles
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Cutler
authors.forename: Lauren A
authors.initials: LA
authors.lastname: Meyer
authors.forename: Susan M
authors.initials: SM
authors.lastname: Brozik
mesh_terms: D001673:Biodegradation, Environmental; D004785:Environmental Pollutants / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D007700:Kinetics; D008163:Luminescent Measurements; D019216:Metals, Heavy / Q000737:chemistry / Q000378:metabolism*; D011848:Radioactive Pollutants / Q000737:chemistry / Q000378:metabolism*; D013725:Terbium / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004785:Environmental Pollutants; D019216:Metals, Heavy; D011848:Radioactive Pollutants; D013725:Terbium