title: Toxicity Induced by a Metal Mixture (Cd, Pb and Zn) in the Yeast Pichia kudriavzevii: The Role of Oxidative Stress.
abstract: The present work aims to contribute for the elucidation of the role of oxidative stress in the toxicity associated with the exposure of Pichia kudriavzevii to multi-metals (Cd, Pb and Zn). Cells of the non-conventional yeast P. kudriavzevii exposed for 6 h to the action of multi-metals accumulated intracellular reactive oxygen species (ROS), evaluated through the oxidation of the probe 2',7'-dichlorodihydrofluorescein diacetate. A progressive loss of membrane integrity (monitored using propidium iodide) was observed in multi-metal-treated cells. The triggering of intracellular ROS accumulation preceded the loss of membrane integrity. These results suggest that the disruption of membrane integrity can be attributed to the oxidative stress. The exposure of yeast cells to single metal showed that, under the concentrations tested, Pb was the metal responsible for the induction of the oxidative stress. Yeast cells coexposed to an antioxidant (ascorbic acid) and multi-metals did not accumulate intracellular ROS, but loss proliferation capacity. Together, the data obtained indicated that intracellular ROS accumulation contributed to metal toxicity, namely for the disruption of membrane integrity of the yeast P. kudriavzevii. It was proposed that Pb toxicity (the metal responsible for the toxic symptoms under the conditions tested) result from the combination of an ionic mechanism and the intracellular ROS accumulation.
authors.affiliation: Bioengineering Laboratory, Chemical Engineering Department, ISEP-School of Engineering of Polytechnic Institute of Porto, Rua Dr António Bernardino de Almeida, 431, 4200-072, Porto, Portugal.|Department of Biology, Federal University of Lavras (UFLA), Lavras, Minas Gerais, Brazil.
authors.forename: Vanessa A
authors.initials: VA
authors.lastname: Mesquita
authors.affiliation: Department of Biology, Federal University of Lavras (UFLA), Lavras, Minas Gerais, Brazil.
authors.forename: Cristina F
authors.initials: CF
authors.lastname: Silva
authors.affiliation: Bioengineering Laboratory, Chemical Engineering Department, ISEP-School of Engineering of Polytechnic Institute of Porto, Rua Dr António Bernardino de Almeida, 431, 4200-072, Porto, Portugal. evs@isep.ipp.pt.|CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal. evs@isep.ipp.pt.
authors.forename: Eduardo V
authors.initials: EV
authors.lastname: Soares
mesh_terms: D002104:Cadmium; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D007854:Lead / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects*; D010843:Pichia / Q000187:drug effects* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015032:Zinc / Q000633:toxicity
chemical_list: D017382:Reactive Oxygen Species; D002104:Cadmium; D007854:Lead; D015032:Zinc