Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.4.6 (urease)
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Paracoccidioides brasiliensis, the causative agent of paracoccidioidomycosis (PCM), was first isolated from armadillos from the Amazonian region where the mycosis is uncommon. In the present study, we report on the high incidence of PCM infection in armadillos from a hyperendemic region of the disease. Four nine-banded armadillos (Dasypus novemcinctus) were captured in the endemic area of Botucatu, Sao Paulo, Brazil, killed by manual cervical dislocation and autopsied under sterile conditions. Fragments of lung, spleen, liver, and mesenteric lymph nodes were processed for histology, cultured on Mycosel agar at 37 degrees C, and homogenized for inoculation into the testis and peritoneum of hamsters. The animals were killed from week 6 to week 20 postinoculation and fragments of liver, lung, spleen, testis, and lymph nodes were cultured on brain heart infusion agar at 37 degrees C. Paracoccidioides brasiliensis was isolated from three armadillos both by direct organ culture and from the liver, spleen, lung, and mesenteric lymph nodes of hamsters. In addition, one positive armadillo presented histologically proven PCM disease in a mesenteric lymph node. The three armadillos isolates (Pb-A1, Pb-A2, and Pb-A4) presented thermodependent dimorphism, urease activity, and casein assimilation, showed amplification of the gp43 gene, and were highly virulent in intratesticularly inoculated hamsters. The isolates expressed the gp43 glycoprotein, the immunodominant antigen of the fungus, and reacted with a pool of sera from PCM patients. Taken together, the present data confirm that armadillos are a natural reservoir of P. brasiliensis and demonstrate that the animal is a sylvan host to the fungus.
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PMID:Isolation of Paracoccidioides brasiliensis from armadillos (Dasypus noveminctus) captured in an endemic area of paracoccidioidomycosis. 957

Paracoccidioides brasiliensis, the etiologic agent of paracoccidioidomycosis, is a dimorphic fungus, which is found as mycelia at 22-26 degrees C and as yeasts at 37 degrees 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. brasiliensis transcriptome. 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 alpha- and beta-glucan synthases, orthologs to chitin synthase and mannosyl transferases, 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 superoxide dismutase, thiol peroxidase and an alternative oxidase were also found. Among the secreted factors, we were able to find phospholipase and urease orthologs in P. brasiliensis transcriptome. Collectively, our results suggest that this organism may possess a vast arsenal of putative virulence genes, allowing the survival in the different host environments.
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PMID:Virulence insights from the Paracoccidioides brasiliensis transcriptome. 1611 Apr 52

An atypical isolate of Paracoccidioides brasiliensis (IFM54648), recovered from the sputum of a Brazilian man, was not detected in immunodiffusion tests for paracoccidioidomycosis and in species-specific PCR for the major antigen 43-kDa glycoprotein coding gene (gp43). The mycological characteristics of the isolate were similar to those of a typical P. brasiliensis. A total of 8 genes were sequenced from IFM54648, and the sequences were compared between the new isolate and other reference isolates and database sequences. We analyzed fragments of the gene sequences that code for gp43, the internal transcribed spacer regions of ribosomal RNA, the D1/D2 domains of the large subunit ribosomal RNA, glucan synthase, chitin synthase, glyoxalase I mRNA, 70-kDa heat-shock protein mRNA and urease. The gene sequences were 98.9-100% identical between IFM54648 and Pb01 (another atypical isolate). When compared to the other typical isolates, the identities were generally lower than 98%. A phylogenetic tree constructed using gp43 sequences showed that IFM54648 clustered with Pb01 at a considerable distance from other isolates. Therefore, this isolate is likely related to Pb01, which has recently been shown to be genetically distinct from other isolates of this species.
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PMID:An atypical Paracoccidioides brasiliensis clinical isolate based on multiple gene analysis. 1922 77