title: The effect of uranium on bacterial viability and cell surface morphology using atomic force microscopy in the presence of bicarbonate ions.
abstract: Past disposal practices at nuclear production facilities have led to the release of liquid waste into the environment creating multiple radionuclide plumes. Microorganisms are known for the ability to interact with radionuclides and impact their mobility in soils and sediments. Gram-positive Arthrobacter sp. are one of the most common bacterial groups in soils and are found in large numbers in subsurface environments contaminated with radionuclides. This study experimentally analyzed changes on the bacteria surface at the nanoscale level after uranium exposure and evaluated the effect of aqueous bicarbonate ions on U(VI) toxicity of a low uranium-tolerant Arthrobacter oxydans strain G968 by investigating changes in adhesion forces and cell dimensions via atomic force microscopy (AFM). Experiments were extended to assess cell viability by the Live/Dead BacLight Bacterial Viability Kit (Molecular Probes) and quantitatively illustrate the effect of uranium exposure in the presence of varying concentrations of bicarbonate ions. AFM and viability studies showed that samples containing bicarbonate were able to withstand uranium toxicity and remained viable. Samples containing no bicarbonate exhibited deformed surfaces and a low height profile, which, in conjunction with viability studies, indicated that the cells were not viable.
authors.affiliation: Applied Research Center, Florida International University, 10555 W. Flagler Street, Miami, FL 33174, USA; Department of Biomedical Engineering, Florida International University, 10555 W. Flagler Street, Miami, FL 33174, USA.
authors.forename: Paola
authors.initials: P
authors.lastname: Sepulveda-Medina
authors.affiliation: Applied Research Center, Florida International University, 10555 W. Flagler Street, Miami, FL 33174, USA. Electronic address: katsenov@fiu.edu.
authors.forename: Yelena
authors.initials: Y
authors.lastname: Katsenovich
authors.affiliation: Applied Research Center, Florida International University, 10555 W. Flagler Street, Miami, FL 33174, USA.
authors.forename: Vishal
authors.initials: V
authors.lastname: Musaramthota
authors.affiliation: Pacific Northwest National Laboratory, PO Box 999, K3-62, Richland, WA 99352, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Lee
authors.affiliation: Pacific Northwest National Laboratory, PO Box 999, K3-62, Richland, WA 99352, USA.
authors.forename: Brady
authors.initials: B
authors.lastname: Lee
authors.affiliation: Department of Biomedical Engineering, Florida International University, 10555 W. Flagler Street, Miami, FL 33174, USA.
authors.forename: Rupak
authors.initials: R
authors.lastname: Dua
authors.affiliation: Applied Research Center, Florida International University, 10555 W. Flagler Street, Miami, FL 33174, USA.
authors.forename: Leonel
authors.initials: L
authors.lastname: Lagos
mesh_terms: D001173:Arthrobacter / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure*; D001639:Bicarbonates / Q000494:pharmacology*; D050296:Microbial Viability / Q000528:radiation effects*; D018625:Microscopy, Atomic Force / Q000379:methods; D014501:Uranium / Q000633:toxicity*
chemical_list: D001639:Bicarbonates; D014501:Uranium
keywords: Aqueous bicarbonate; Arthrobacter sp.; Atomic force microscopy; Live/dead analysis; Toxicity