XI International Meeting on Paracoccidioidomycosis

XI International Meeting on Paracoccidioidomycosis

Resume:4-1

Oral / Poster

4-1

A study of Paracoccidioides brasiliensis proteome under oxidative stress

Authors:

Daciene de Arruda Grossklaus (UNB - Universidade de BrasíliaUFG - Universidade Federal de Goiás) ; Alexandre Melo Bailão (UFG - Universidade Federal de Goiás) ; Tereza Cristina Vieira de Rezende (UNB - Universidade de BrasíliaUFG - Universidade Federal de Goiás) ; Ronney Fernandes Chagas (UNB - Universidade de BrasíliaUFG - Universidade Federal de Goiás) ; Clayton Luiz Borges (UFG - Universidade Federal de Goiás) ; Célia Maria de Almeida Soares (UFG - Universidade Federal de GoiásUNB - Universidade de Brasília)

Abstract

Paracoccidioides brasiliensis is the etiologic agent of paracoccidioidomycosis, a disease acquired by the inhalation of propagules from the mycelial phase of the fungus. Fungal survival inside human depends on evasion from the immune system and adaptation to the host environment. Among different insults which P. brasiliensis has to handle are reactive oxygen species produced by the human host cells, and by the fungal metabolism. Organisms have developed a series of antioxidant defense mechanisms to maintain and protect the cells against oxidative damage. To study the defense mechanisms of P. brasiliensis in the hostile environment the fungus may encounter during infection, we performed proteomic analysis of P. brasiliensis (ATCC MYA – 826) in the presence of hydrogen peroxide (H2O2). The proteins were subjected to two-dimensional gel electrophoresis (2-DE). Differentially expressed proteins in 2-DE analysis were subjected to identification by mass spectrometry. The search in the database for identification of each protein was performed by submitting the monoisotopic mass of the peptides to the program MASCOT (http://www.matrixscience.com). The analysis showed 38 total proteins with volume changes (35 over-expressed and 3 under-expressed). Cells submitted to oxidative stress seem to defend themselves by various mechanisms, including metabolic switches, synthesis of proteins to replace the damaged ones, and active degradation of damaged proteins. Interestingly, antioxidant enzymes are not so prominent in the P. brasiliensis response, which rather emphasizes a deep reorientation in the central metabolism, as suggested by the upregulation of a number of proteins of gluconeogenesis. The pentose-phosphate pathway seems to be also induced, probably to provide NADPH, which is the reducing substrate used by the key antioxidant glutathione peroxidase and the peroxiredoxin systems. These results allow a better understanding of the adaptation process of P. brasiliensis in the host.਀匀甀瀀瀀漀爀琀攀搀戀礀㨀䌀一倀焀Ⰰ 䘀䤀一䔀倀Ⰰ 䘀䄀倀䔀䜀⸀

Keyword: Mass spectrometry, Oxidative stress, Paracoccidioides brasiliensis, Proteome, Two-dimensional gel electrophoresis

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