Resumo

Paracoccidioides is the etiological agent of paracoccidioidomycosis, the most important systemic mycosis endemic in Latin America. Paracoccidioides is a dimorphic fungus; mycelia is found in soil at temperatures below 25ºC, while in host tissues, and temperature 36-37ºC the fungus takes the yeast form. Infection begins with the inhalation of conidia and or mycelia propagules that upon reaching the host lungs differentiate into yeast, establishing disease. Transition from mycelium to yeast is involved in the virulence of this pathogen and this aspect of morphogenesis deserves special attention due to its relevance to the fungal virulence. In the present study, we used the two-dimensional gel electrophoresis to evaluate the differential proteomic profile of cells ongoing transition from mycelium to yeast after 22 h the temperature shift from 22ºC to 36ºC (P. brasiliensis Pb-18 phylogenetic lineages S1). Silver-stained gels of three independent biological replicates were digitalized and the images were analyzed using the ImageMaster 2D Platinum 6.0 software (GE Healthcare). Spot detection and matching was performed. It was performed statistical analysis (one-way ANOVA) and 157 spots showed differential expression (p < 0.05). Among them 45 spots were over expressed in mycelium, 42 in the transition from mycelium to yeast and 70 in yeast. In addition some spots were detected just in one phase: 29 spots in mycelium, 91 in the transition from mycelium to yeast cells and 149 in yeast. The spots of interest will excised from gels and identified by mass spectrometric (MALDI Q-TOF). The analysis of the functional categories to which those cytoplasmic proteins belong, as well as comparison analysis with other members of the genus Paracoccidioides, will provide a comprehension the metabolic reorganization that occurs during the mycelium to yeast morphological transition, providing putative virulence factors.