title: Bacterial and H2O2 stress-induced apoptosis-like events in Cryptococcus neoformans.
abstract: Cell death induced by adherence of Staphylococcus aureus was observed in Cryptococcus neoformans. To investigate this death mechanism, we examined three factors: actin dynamics using rhodamine-phalloidin staining, accumulation of reactive oxygen species (ROS) via conversion of 2',7'-dichlorofluorescein diacetate to 2',7'-dichlorofluorescein, and DNA fragmentation via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). In co-culture, actin visibly clumped and the percentage of ROS- and TUNEL-positive cells increased. The same cellular events were observed in C. neoformans after addition of hydrogen peroxide (H2O2), creating a bacterial cell-free system. After H2O2 treatment and cell disruption, C. neoformans proteins in soluble fraction were separated by two-dimensional (2-D) electrophoresis. A voltage-dependent ion-selective channel was identified as one of the stress-enhanced proteins. Thus, the death of C. neoformans was accompanied by decreased actin turnover, enhanced ROS accumulation, and DNA fragmentation. Cell death appeared similar to apoptosis via mitochondrial pathways.
authors.affiliation: Department of Microbiology, Meiji Pharmaceutical University, 2-522-1, Noshio, Kiyose, Tokyo 204-8588, Japan. ikeda@my-pharm.ac.jp
authors.forename: Reiko
authors.initials: R
authors.lastname: Ikeda
authors.forename: Kanako
authors.initials: K
authors.lastname: Sawamura
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001422:Bacterial Adhesion / Q000502:physiology*; D003455:Cryptococcus neoformans / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D053938:DNA Fragmentation; D018869:Heat-Shock Response; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology*; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D013211:Staphylococcus aureus / Q000502:physiology*; D050994:Voltage-Dependent Anion Channels
chemical_list: D017382:Reactive Oxygen Species; D050994:Voltage-Dependent Anion Channels; D006861:Hydrogen Peroxide