title: Immobilization of Shewanella oneidensis MR-1 in diffusive gradients in thin films for determining metal bioavailability.
abstract: Assessing metal bioavailability in soil is important in modeling the effects of metal toxicity on the surrounding ecosystem. Current methods based on diffusive gradient thin films (DGTs) and Gel-Integrated Microelectrode are limited in their availability and sensitivity. To address this, Shewanella oneidensis, an anaerobic iron reducing bacterium, was incorporated into a thin layer of agarose to replace the polyacrylamide gel that is normally present in DGT to form biologically mobilizing DGT (BMDGT). Viability analysis revealed that 16-35% of the cells remained viable within the BMDGTs depending on the culturing conditions over a 20 h period with/without metals. Deployment of BMDGTs in standardized metal solutions showed significant differences to cell-free BMDGTs when cells grown in Luria Broth (LB) were incorporated into BMDGTs and deployed under anaerobic conditions. Deployment of these BMDGTs in hematite revealed no significant differences between BMDGTs and BMDGTs containing heat killed cells. Whether heat killed cells retain the ability to affect bioavailability is uncertain. This is the first study to investigate how a microorganism that was incorporated into a DGT device such as the metal reducing bacteria, S. oneidensis, may affect the mobility of metals.
authors.affiliation: Lancaster Environmental Centre, Lancaster University, Bailrigg, Lancaster LA1 4YQ, UK.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Baker
authors.affiliation: School of Biomedical Sciences, 1.14 Hodgkin Building, Guy's Campus, London LE1 1UL, UK.
authors.forename: Christer
authors.initials: C
authors.lastname: Högstrand
authors.affiliation: School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: Jamie
authors.initials: J
authors.lastname: Lead
authors.affiliation: Division of Biomedicine and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK.
authors.forename: Roger W
authors.initials: RW
authors.lastname: Pickup
authors.affiliation: Lancaster Environmental Centre, Lancaster University, Bailrigg, Lancaster LA1 4YQ, UK.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
mesh_terms: D001682:Biological Availability; D018914:Cells, Immobilized; D004058:Diffusion; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D008670:Metals / Q000032:analysis*; D020592:Shewanella / Q000187:drug effects* / Q000254:growth & development*; D012987:Soil / Q000737:chemistry* / Q000592:standards; D012989:Soil Pollutants / Q000032:analysis*; D012996:Solutions
chemical_list: D008670:Metals; D012987:Soil; D012989:Soil Pollutants; D012996:Solutions
keywords: BacLight; Biological mobilizing DGT; Diffusive gradient thin films (DGT); Shewanella oneidensis