title: Polyhydroxyfullerene binds cadmium ions and alleviates metal-induced oxidative stress in Saccharomyces cerevisiae.
abstract: The water-soluble polyhydroxyfullerene (PHF) is a functionalized carbon nanomaterial with several industrial and commercial applications. There have been controversial reports on the toxicity and/or antioxidant properties of fullerenes and their derivatives. Conversely, metals have been recognized as toxic mainly due to their ability to induce oxidative stress in living organisms. We investigated the interactive effects of PHF and cadmium ions (Cd) on the model yeast Saccharomyces cerevisiae by exposing cells to Cd (≤5 mg liter(-1)) in the absence or presence of PHF (≤500 mg liter(-1)) at different pHs (5.8 to 6.8). In the absence of Cd, PHF stimulated yeast growth up to 10.4%. Cd inhibited growth up to 79.7%, induced intracellular accumulation of reactive oxygen species (ROS), and promoted plasma membrane disruption in a dose- and pH-dependent manner. The negative effects of Cd on growth were attenuated by the presence of PHF, and maximum growth recovery (53.8%) was obtained at the highest PHF concentration and pH. The coexposure to Cd and PHF decreased ROS accumulation up to 36.7% and membrane disruption up to 30.7% in a dose- and pH-dependent manner. Two mechanisms helped to explain the role of PHF in alleviating Cd toxicity to yeasts: PHF decreased Cd-induced oxidative stress and bound significant amounts of Cd in the extracellular medium, reducing its bioavailability to the cells.
authors.affiliation: Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus of Gualtar, Braga, Portugal.
authors.forename: Arunava
authors.initials: A
authors.lastname: Pradhan
authors.affiliation: Institute for Biotechnology and Bioengineering/Center for Molecular and Structural Biomedicine, Department of Chemistry and Biochemistry, Faculty of Sciences and Technology, University of Algarve, Campus of Gambelas, Faro, Portugal.
authors.forename: José Paulo
authors.initials: JP
authors.lastname: Pinheiro
authors.affiliation: Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus of Gualtar, Braga, Portugal.
authors.forename: Sahadevan
authors.initials: S
authors.lastname: Seena
authors.affiliation: Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus of Gualtar, Braga, Portugal.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Pascoal
authors.affiliation: Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus of Gualtar, Braga, Portugal fcassio@bio.uminho.pt.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Cássio
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D002104:Cadmium / Q000378:metabolism* / Q000633:toxicity*; D002413:Cations, Divalent / Q000378:metabolism / Q000633:toxicity; D002462:Cell Membrane / Q000187:drug effects; D003593:Cytoplasm / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D037741:Fullerenes / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000032:analysis; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000975:Antioxidants; D002413:Cations, Divalent; D037741:Fullerenes; D017382:Reactive Oxygen Species; D002104:Cadmium