Project description:Paracoccidioidomycosis (PCM) is an endemic mycosis in Latin America. The PCM is a systemic disease caused by the thermo dimorphic fungus Paracoccidioides spp, which can exist as mycelia and yeast forms. The mycelia form can be found in environment at temperatures between 18 °C and 25 °C and produces spores or conidia. The PCM infection route occurs by the inhalation of conidia. Once in the lungs, these particles are converted into yeasts pathogenic form. Until now, metabolic aspects and virulence factors related to Paracoccidioides lutzii infective propagule are little understood. In this concern, a global proteomic study of P. lutzii conidia was performed. For conidia production, the mycelia of the isolate Pb01 were cultured in potato agar medium during 90 days at 18 °C. Obtained conidia were collected and purified. The proteins were extracted and subjected to tryptic digestion followed by identification by NanoUPLC-MSE approach. We identified a total of 242 proteins in P. lutzii conidia which were subjected to in silico functional analysis Proteins putatively acting as adhesins, such as GAPDH, enolase, and the glycoprotein β-1,3-glucanosyltransferase (gel2) were identified during our analysis. We also identified proteins related to signal transduction pathways, such as Ras and RhoA GTPases, previously demonstrated to be required for morphologic changes in pathogenic fungi. Proteins related to evasion, defense and virulence were also identified. Proteins acting during temperature shifts or oxidative stress provided by the host environment such as HSP90, catalase, mitochondrial peroxiredoxin Prx1 were identified. It were also identified proteins related to energy production and protein biosynthesis, which can provide important aspects to survival of this resting cells. These results highlight that P. lutzii conidia contain proteins that can contribute to its maintenance in the environment and also molecules related to host-pathogen interactions.
Project description:Paracoccidioides brasiliensis is a thermodimorphic fungus associated with paracoccidioidomycosis (PCM), a prevalent systemic mycosis in South America. In humans, infection starts by inhalation of fungal propagules, which reach the pulmonary epithelium and transform into the yeast parasitic form. Thus, the mycelium-to-yeast transition is of particular interest because conversion to yeast is essential for infection. We have used a P. brasiliensis biochip, carrying sequences of 4,692 genes from this fungus to monitor gene expression at several time points of the mycelium-to-yeast morphological shift (from 5 to 120 h). Keywords: Time Course
Project description:Species of the genus Paracoccidioides cause a systemic infection in human patients. Yeast cells of Paracoccidioides spp. produce melanin in the presence of L-dihydroxyphenylalanine and during infection, which may impact the pathogen survival into the host. To better understand the metabolic changes that occur in melanized Paracoccidioides spp. cells, a proteomic approach was performed to compare melanized and non-melanized Paracoccidioides brasiliensis and Paracoccidioides lutzii yeast cells. Melanization was conducted using L-dihydroxyphenylalanine as a precursor and quantitative proteomics was performed using reversed-phase chromatography coupled to high resolution mass spectrometry. When comparing melanized versus non-melanized cells, 999 and 577 differentially abundant proteins were identified for P. brasiliensis and P. lutzii, respectively. Functional enrichment and comparative analysis revealed 30 abundant biological processes in melanized P. brasiliensis and 18 in P. lutzii, while non-melanized cells from these species had 21 and 25 differentially abundant processes, respectively. Melanized cells presented abundance of other virulence-associated proteins, such as phospholipase, proteases, superoxide dismutase, heat-shock proteins, as well as proteins related to cell-wall remodeling and vesicular transport. The results suggest that L-dihydroxyphenilalanine increases virulence of Paracoccidioides spp. through a complex mechanism involving not only melanin, but other virulence factors as well.
