Aldo Henrique Tavares, Simoneide Souza Silva, Vanilce Vilmar Bernardes, Andréa Queiróz Maranhão, Cynthia Maria Kyaw, Marcio Poças-Fonseca and Ildinete Silva-Pereira
Published June 30, 2005
Genet. Mol. Res. 4 (2): 372-389 (2005)
About the Authors
Aldo Henrique Tavares, Simoneide Souza Silva, Vanilce Vilmar Bernardes, Andréa Queiróz Maranhão, Cynthia Maria Kyaw, Marcio Poças-Fonseca and Ildinete Silva-Pereira
Corresponding author
I. Silva-Pereira
Email: xocolau@unb.br
ABSTRACT
Paracoccidioidesbrasiliensis, the etiologic agent of paracoccidioidomycosis, is a dimorphic fungus, which is found as mycelia at 22-26°C and as yeasts at 37°C. A remarkable feature common to several pathogenic fungi is their ability to differentiate from mycelium to yeast morphologies, or vice-versa. Although P. brasiliensis is a recognized pathogen for humans, little is known about its virulence genes. In this sense, we performed a search for putative virulence genes in the P. brasiliensistranscriptome. BLAST comparative analyses were done among P. brasilienses assembled expressed sequence tags (PbAESTs) and the sequences deposited in GenBank. As a result, the putative virulence PbAESTs were grouped into five classes, metabolism-, cell wall-, detoxification-related, secreted factors, and other determinants. Among these, we have identified orthologs of the glyoxylate cycle enzymes, a metabolic pathway involved in the virulence of bacteria and fungi. Besides the previously described α- and β-glucansynthases, orthologs to chitin synthase and mannosyltransferases, also important in cell wall synthesis and stabilization, were identified. With respect to the enzymes involved in the intracellular survival of P. brasiliensis, orthologs to superoxidedismutase, thiolperoxidase and an alternative oxidase were also found. Among the secreted factors, we were able to find phospholipase and ureaseorthologs in P. brasiliensistranscriptome. Collectively, our results suggest that this organism may possess a vast arsenal of putative virulence genes, allowing the survival in the different host environments.
Key words: Paracoccidioidesbrasiliensis, Dimorphism, Virulence,Transcriptome analysis, Pathogenicity, Host-pathogen interaction.