title: Improvement of tolerance to lead by filamentous fungus Pleurotus ostreatus HAU-2 and its oxidative responses.
abstract: Wastewater contaminated with heavy metals is a world-wide concern. One biological treatment strategy includes filamentous fungi capable of extracellular adsorption and intracellular bioaccumulation. Here we report that an acclimated strain of filamentous fungus Pleurotus ostreatus HAU-2 can withstand Pb up to 1500 mg L(-1) Pb, conditions in which the wildtype strain cannot grow. The acclimated strain grew in liquid culture under 500 mg L(-1) Pb without significant abnormity in biomass and morphology, and was able to remove significant amounts of heavy metals with rate of 99.1% at 200 mg L(-1) and 63.3% at 1500 mg L(-1). Intracellular bioaccumulation as well as extracellular adsorption both contributed the Pb reduction. Pb induced levels of H2O2, and its concentration reached 72.9-100.9 μmol g(-1) under 200-1000 mg L(-1) Pb. A relatively higher malonaldehyde (MDA) concentration (8.06-7.59 nmol g(-1)) was also observed at 500-1500 mg L(-1) Pb, indicating that Pb exposure resulted in oxidative damage. The fungal cells also defended against the attack of reactive oxygen species by producing antioxidants. Of the three antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), CAT was the most responsive and the maximal enzyme activity was 15.8 U mg(-1) protein. Additionally, glutathione (GSH) might also play a role (3.16-3.21 mg g(-1) protein) in detoxification under relatively low Pb concentration (100-200 mg L(-1)). Our findings suggested that filamentous fungus could be selected for increased tolerance to heavy metals and that CAT and GSH might be important components of this tolerance.
authors.affiliation: College of Life Science, Henan Agricultural University, Zhengzhou, 450002, China.
authors.forename: Shimin
authors.initials: S
authors.lastname: Zhang
authors.affiliation: College of Life Science, Henan Agricultural University, Zhengzhou, 450002, China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Henan Provincial Corporation of China National Tobacco Corporation, Zhengzhou, 450018, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Chang
authors.affiliation: Henan Provincial Corporation of China National Tobacco Corporation, Zhengzhou, 450018, China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: College of Forestry, Henan Agricultural University, Zhengzhou, 450002, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Wang
authors.affiliation: College of Forestry, Henan Agricultural University, Zhengzhou, 450002, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: College of Forestry, Henan Agricultural University, Zhengzhou, 450002, China.
authors.forename: Xitian
authors.initials: X
authors.lastname: Yang
authors.affiliation: Institute of Plant Nutrient and Environmental Resources, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, China.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Industrial Crop Research Institute, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, China.
authors.forename: Guixiao
authors.initials: G
authors.lastname: La
authors.affiliation: College of Life Science, Henan Agricultural University, Zhengzhou, 450002, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Wu
authors.affiliation: College of Forestry, Henan Agricultural University, Zhengzhou, 450002, China. Electronic address: zhi110ming@163.com.
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: College of Forestry, Henan Agricultural University, Zhengzhou, 450002, China. Electronic address: xzli2015@sina.com.
authors.forename: Xuanzhen
authors.initials: X
authors.lastname: Li
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D007854:Lead / Q000378:metabolism*; D008315:Malondialdehyde / Q000378:metabolism; D010084:Oxidation-Reduction; D009195:Peroxidase / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D020076:Pleurotus / Q000201:enzymology / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005656:Fungal Proteins; D017382:Reactive Oxygen Species; D007854:Lead; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D010544:Peroxidases; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase; D005978:Glutathione
keywords: Filamentous fungi; Lead; Pleurotus ostreatus HAU-2; Removal; Tolerance