Paracoccidioides brasiliensis, is a human thermal dimorphic pathogenic fungus, etiologic agent of most common systemic mycosis in Latin America, paracoccidioidomycosis (PCM). P. brasiliensis infection occurs by inhalation of conidia or mycelial fragments by the host, followed by their differentiation into yeast cells. To disease development, is indispensable that conidia accommodated in the alveoli pass into yeast phase event dependent on temperature increase. This fungus is considered a facultative intracellular pathogen able to survive and replicate within non-activated macrophages. Survivel of P. brasiliensis inside the host depends on the adaptation of this fungal pathogen to different conditions, namely oxidative stress imposed by immune cells, particularly alveaolar macrophages. Among the molecules that exert fungicidal action are hydrogen peroxide (H2O2) and derivatives. Transcriptome analysis of P. brasiliensis, internalized by murine macrophages, showed pathogen expressing several genes involved in the oxidative stress response, demonstrating antioxidant mechanisms and response of parasite to this type of stress. Studies in our laboratory we show that low concentrations of H2O2 induced cell proliferation in P. brasiliensis, while intermediary and high concentrations led to survive and decreased viability respectively. However, studies of protein post-translational modifications (PTM), capable of eliciting responses survival of the fungus in the host, as well as signaling pathways and transcriptional regulation of microorganisms in response to different types of stress are still scarce or inexistent. Thereby, this project proposes to evaluate the fungal phosphoproteome after oxidative stress (with low and higher levels of H2O2). We will extract, digest with trypsin, and analyze by liquid chromatography-tandem mass spectrometry (LC-MS/MS) the proteins of P. brasiliensis with and without treatment with H2O2. This study should contribute to the understanding of the biology of this fungus and its interaction with the host.
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