title: Impact of photocatalysis on fungal cells: depiction of cellular and molecular effects on Saccharomyces cerevisiae.
abstract: We have investigated the antimicrobial effects of photocatalysis on the yeast model Saccharomyces cerevisiae. To accurately study the antimicrobial mechanisms of the photocatalytic process, we focused our investigations on two questions: the entry of the nanoparticles in treated cells and the fate of the intracellular environment. Transmission electronic microscopy did not reveal any entry of nanoparticles within the cells, even for long exposure times, despite degradation of the cell wall space and deconstruction of cellular compartments. In contrast to proteins located at the periphery of the cells, intracellular proteins did not disappear uniformly. Disappearance or persistence of proteins from the pool of oxidized intracellular isoforms was not correlated to their functions. Altogether, our data suggested that photocatalysis induces the establishment of an intracellular oxidative environment. This hypothesis was sustained by the detection of an increased level of superoxide ions (O2°(-)) in treated cells and by greater cell cultivability for cells expressing oxidant stress response genes during photocatalytic exposure. The increase in intracellular ROS, which was not connected to the entry of nanoparticles within the cells or to a direct contact with the plasma membrane, could be the result of an imbalance in redox status amplified by chain reactions. Moreover, we expanded our study to other yeast and filamentous fungi and pointed out that, in contrast to the laboratory model S. cerevisiae, some environmental strains are very resistant to photocatalysis. This could be related to the cell wall composition and structure.
authors.affiliation: Université de Lyon, Université Lyon 1, CNRS-UCB-INSA, UMR 5240 Microbiologie, Adaptation et Pathogénie, Génétique Moléculaire des Levures, Domaine Scientifique de la Doua, Villeurbanne, France Université de Lyon, Université Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de Recherches sur la Catalyse et l'Environnement de Lyon, Villeurbanne, France.
authors.forename: Sana
authors.initials: S
authors.lastname: Thabet
authors.affiliation: Université de Lyon, Université Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de Recherches sur la Catalyse et l'Environnement de Lyon, Villeurbanne, France.
authors.forename: France
authors.initials: F
authors.lastname: Simonet
authors.affiliation: Université de Lyon, Université Lyon 1, CNRS-UCB-INSA, UMR 5240 Microbiologie, Adaptation et Pathogénie, Génétique Moléculaire des Levures, Domaine Scientifique de la Doua, Villeurbanne, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Lemaire
authors.affiliation: Université de Lyon, Université Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de Recherches sur la Catalyse et l'Environnement de Lyon, Villeurbanne, France.
authors.forename: Chantal
authors.initials: C
authors.lastname: Guillard
authors.affiliation: Université de Lyon, Université Lyon 1, CNRS-UCB-INSA, UMR 5240 Microbiologie, Adaptation et Pathogénie, Génétique Moléculaire des Levures, Domaine Scientifique de la Doua, Villeurbanne, France pascale.cotton@univ-lyon1.fr.
authors.forename: Pascale
authors.initials: P
authors.lastname: Cotton
mesh_terms: D002473:Cell Wall / Q000378:metabolism / Q000528:radiation effects / Q000648:ultrastructure; D008027:Light; D046529:Microscopy, Electron, Transmission; D018384:Oxidative Stress / Q000528:radiation effects; D012441:Saccharomyces cerevisiae / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism
chemical_list: D029701:Saccharomyces cerevisiae Proteins