Daghino Stefania, Turci Francesco, Tomatis Maura, Favier Alain, Perotto Silvia, Douki Thierry, Fubini Bice
Interdepartmental Centre G. Scansetti for Studies on Asbestos and Other Toxic Particulates, University of Torino, via Pietro Giuria 7, 10125 Torino, Italy.
Environ Sci Technol. 2006 Sep 15;40(18):5793-8. doi: 10.1021/es060881v.
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.
一些生长在石棉纤维上的土壤真菌会释放螯合剂和抗氧化剂。因此，真菌的生物风化潜力被设想为富石棉土壤生物修复的一条可能途径，目前尚无针对此类土壤的灭活程序。本研究报告了真菌介导的纤维表面反应性及其体外损伤DNA潜力的改变。从含温石棉岩石碎片中分离出的真菌中，挑选出了在铁提取方面最有效的两种真菌，即轮枝菌属和拟青霉属，并与之前报道可改变石棉纤维表面反应性的尖孢镰刀菌进行了平行研究。将一份来自西阿尔卑斯山的温石棉样品和一份国际癌症研究机构（UICC）标准的青石棉样品分别在有或没有真菌的情况下进行培养。所有真菌都从两种纤维中提取了铁（轮枝菌属从青石棉中提取了7.3%，从温石棉中提取了33.6%），并将其释放到培养基中。尖孢镰刀菌和拟青霉属抑制了纤维释放羟基自由基的潜力，而轮枝菌属对青石棉起到了抑制作用，但对温石棉却增强了这种作用，这是活性铁持续迁移的一个标志。在生长培养基中但无真菌条件下培养的纤维，通过8-氧代-7,8-二氢-2'-脱氧鸟苷的生成来衡量，在体外表现出显著的损伤DNA的潜力，而所有真菌都降低了这种作用。因此，真菌可被视为富石棉土壤生物修复的合适候选者，通过这种方式，负责DNA损伤的活性铁离子会逐渐从纤维中被去除。
