Biofilms are complex and dynamic structures, formed by aggregated microorganisms and bound to surfaces by means of an extracellular polymer matrix, providing a stable protected environment and associated with greater antimicrobial resistance. Recently, the ability to form biofilm was identified in Paracoccidioides brasiliensis both in vitro and in vivo. This agent can cause infectious processes in various parts of the human body, such as the oral cavity. Oral lesions may be associated with several bacteria and the co-aggregation of P. brasiliensis with these bacteria has not yet been demonstrated, but potentially may lead to more painful and difficult treatment processes. On the other hand, the basic principles of biofilm formation and molecular understanding of the formation and structural organization of P. brasiliensis biofilm need to be known for better therapeutic approaches. Studies report that there are some genes that may be more expressive and important during cell wall production and biofilm formation. Then, the aim of this study was to characterize the structural elements of the P. brasiliensis biofilm matrix in monospecie and to evaluate its gene expression by RT-qPCR analysis, as well as the interaction of P. brasiliensis with the bacteria Streptococcus mutans and Staphylococcus aureus. These strains will be used to induce biofilms in vitro in microplates. The cell viability of the biofilms will be evaluated by the tetrazolium salt reduction test (XTT) and topography and microstructures by scanning electron microscopy. Structural elements of the matrix such as DNA, polysaccharides, enzymes and proteins will be labeled with fluorochromes, visualized by epifluorescence microscopy and quantified by molecular fluorescence spectrometry. To determine the biomass formed by the interaction of P. brasiliensis with S. mutans and S. aureus, the violet crystal method will be used, and the agar plating will allow the determination of the viable organisms count. The study may contribute with new knowledge about paracoccidioidomycosis, a disease that represents an important public health problem in Brazil and Latin America.
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