title: Soil fungi reduce the iron content and the DNA damaging effects of asbestos fibers.
abstract: Some soil fungi growing on asbestos fibers release chelators and antioxidants. The bioweathering potential of fungi has thus been envisaged as a possible route for bioremediation of asbestos rich soils, where no inactivation procedures have been established so far. The present study reports fungal-mediated modification of the surface reactivity of the fibers and of their potential to damage DNA in vitro. Verticillium sp. and Paecilomyces sp. were selected among the fungi isolated from fragments of chrysotile bearing rocks, as the most potent in iron extraction, and studied in parallel with F. oxysporum, previously reported to modify the surface reactivity of asbestos fibers. One sample of chrysotile from the Western Alps and a sample of UICC (Union Internationale Contre le Cancer) crocidolite were incubated with or without fungi. All fungi extracted iron from both fibers (7.3% from crocidolite and 33.6% from chrysotile by Verticillium sp.), releasing it into the medium. F. oxysporum and Paecilomyces sp. suppressed the potential of the fibers to release hydroxyl radical, while Verticillium sp. suppressed it on crocidolite but enhanced it on chrysotile, a hallmark of ongoing mobilization of reactive iron. Fibers incubated in the growth medium, but in the absence of fungi, exhibited a remarkable potential to damage DNA in vitro, measured by the generation of 8-oxo-7,8-dihydro-2'-deoxyguanosine, while all the fungi reduced such effect. Fungi may thus be regarded as appropriate candidates for bioremediation of asbestos rich soils whereby the reactive iron ions responsible for DNA damage are progressively removed from the fibers.
authors.affiliation: Interdepartmental Centre G. Scansetti for Studies on Asbestos and Other Toxic Particulates, University of Torino, via Pietro Giuria 7, 10125 Torino, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Daghino
authors.forename: Francesco
authors.initials: F
authors.lastname: Turci
authors.forename: Maura
authors.initials: M
authors.lastname: Tomatis
authors.forename: Alain
authors.initials: A
authors.lastname: Favier
authors.forename: Silvia
authors.initials: S
authors.lastname: Perotto
authors.forename: Thierry
authors.initials: T
authors.lastname: Douki
authors.forename: Bice
authors.initials: B
authors.lastname: Fubini
mesh_terms: D017638:Asbestos, Crocidolite / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D017632:Asbestos, Serpentine / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D004247:DNA / Q000737:chemistry / Q000187:drug effects; D004249:DNA Damage; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism; D007501:Iron / Q000737:chemistry / Q000378:metabolism*; D008906:Mining; D018384:Oxidative Stress; D010143:Paecilomyces / Q000302:isolation & purification / Q000378:metabolism*; D012988:Soil Microbiology; D020172:Verticillium / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D017632:Asbestos, Serpentine; D005609:Free Radicals; D017638:Asbestos, Crocidolite; D004247:DNA; C427203:calf thymus DNA; D007501:Iron