title: Involvement of an alternative oxidase in oxidative stress and mycelium-to-yeast differentiation in Paracoccidioides brasiliensis.
abstract: Paracoccidioides brasiliensis is a thermodimorphic human pathogenic fungus that causes paracoccidioidomycosis (PCM), which is the most prevalent systemic mycosis in Latin America. Differentiation from the mycelial to the yeast form (M-to-Y) is an essential step for the establishment of PCM. We evaluated the involvement of mitochondria and intracellular oxidative stress in M-to-Y differentiation. M-to-Y transition was delayed by the inhibition of mitochondrial complexes III and IV or alternative oxidase (AOX) and was blocked by the association of AOX with complex III or IV inhibitors. The expression of P. brasiliensis aox (Pbaox) was developmentally regulated through M-to-Y differentiation, wherein the highest levels were achieved in the first 24 h and during the yeast exponential growth phase; Pbaox was upregulated by oxidative stress. Pbaox was cloned, and its heterologous expression conferred cyanide-resistant respiration in Saccharomyces cerevisiae and Escherichia coli and reduced oxidative stress in S. cerevisiae cells. These results reinforce the role of PbAOX in intracellular redox balancing and demonstrate its involvement, as well as that of other components of the mitochondrial respiratory chain complexes, in the early stages of the M-to-Y differentiation of P. brasiliensis.
authors.affiliation: Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. Café, s/n, 14040-903 Ribeirão Preto, São Paulo, Brazil.
authors.forename: Vicente P
authors.initials: VP
authors.lastname: Martins
authors.forename: Taisa M
authors.initials: TM
authors.lastname: Dinamarco
authors.forename: Frederico M
authors.initials: FM
authors.lastname: Soriani
authors.forename: Valéria G
authors.initials: VG
authors.lastname: Tudella
authors.forename: Sergio C
authors.initials: SC
authors.lastname: Oliveira
authors.forename: Gustavo H
authors.initials: GH
authors.lastname: Goldman
authors.forename: Carlos
authors.initials: C
authors.lastname: Curti
authors.forename: Sérgio A
authors.initials: SA
authors.lastname: Uyemura
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology; D000968:Antimycin A / Q000494:pharmacology; D004579:Electron Transport / Q000187:drug effects; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D006801:Humans; D024101:Mitochondrial Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D025282:Mycelium / Q000502:physiology*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010088:Oxidoreductases / Q000096:biosynthesis*; D010228:Paracoccidioides / Q000166:cytology / Q000254:growth & development / Q000502:physiology*; D010940:Plant Proteins; D011190:Potassium Cyanide / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation; D000099188:Alternative Oxidase
chemical_list: D000935:Antifungal Agents; D000968:Antimycin A; D005656:Fungal Proteins; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010940:Plant Proteins; D011190:Potassium Cyanide; D017382:Reactive Oxygen Species; D011993:Recombinant Fusion Proteins; D000099188:Alternative Oxidase