title: X-ray absorption spectroscopy (XAS) of toxic metal mineral transformations by fungi.
abstract: Fungi can be highly efficient biogeochemical agents and accumulators of soluble and particulate forms of metals. This work aims to understand some of the physico-chemical mechanisms involved in toxic metal transformations focusing on the speciation of metals accumulated by fungi and mycorrhizal associations. The amorphous state or poor crystallinity of metal complexes within biomass and relatively low metal concentrations make the determination of metal speciation in biological systems a challenging problem but this can be overcome by using synchrotron-based element-specific X-ray absorption spectroscopy (XAS) techniques. In this research, we have exposed fungi and ectomycorrhizas to a variety of copper-, zinc- and lead-containing minerals. X-ray absorption spectroscopy studies revealed that oxygen ligands (phosphate, carboxylate) played a major role in toxic metal coordination within the fungal and ectomycorrhizal biomass during the accumulation of mobilized toxic metals. Coordination of toxic metals within biomass depended on the fungal species, initial mineral composition, the nitrogen source, and the physiological state/age of the fungal mycelium.
authors.affiliation: Division of Environmental and Applied Biology, Biological Sciences Institute, School of Life Sciences, University of Dundee, Dundee, DD1 4HN, UK.
authors.forename: Marina
authors.initials: M
authors.lastname: Fomina
authors.forename: John
authors.initials: J
authors.lastname: Charnock
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Bowen
authors.forename: Geoffrey M
authors.initials: GM
authors.lastname: Gadd
mesh_terms: D001234:Aspergillus niger / Q000378:metabolism / Q000648:ultrastructure; D001487:Basidiomycota / Q000378:metabolism / Q000648:ultrastructure; D052982:Beauveria / Q000378:metabolism / Q000648:ultrastructure; D018533:Biomass; D003300:Copper / Q000737:chemistry / Q000378:metabolism*; D005583:Fourier Analysis; D007854:Lead / Q000737:chemistry / Q000378:metabolism*; D038821:Mycorrhizae / Q000378:metabolism* / Q000648:ultrastructure; D010407:Penicillium / Q000378:metabolism / Q000648:ultrastructure; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology; D013057:Spectrum Analysis / Q000379:methods; D014965:X-Rays; D015032:Zinc / Q000737:chemistry / Q000378:metabolism*
chemical_list: D007854:Lead; D003300:Copper; D015032:Zinc