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Paracoccidioides brasiliensis is a fungal human pathogen with a wide distribution in Latin America. It causes paracoccidioidomycosis, the most widespread systemic mycosis in Latin America. Although gene expression in P. brasiliensis had been studied, little is known about the genome sequences expressed by this species during the infection process. To better understand the infection process, 4934 expressed sequence tags (ESTs) derived from a non-normalized cDNA library from P. brasiliensis (isolate Pb01) yeast-phase cells recovered from the livers of infected mice were annotated and clustered to a UniGene (clusters containing sequences that represent a unique gene) set with 1602 members. A large-scale comparative analysis was performed between the UniGene sequences of P. brasiliensis yeast-phase cells recovered from infected mice and a database constructed with sequences of the yeast-phase and mycelium transcriptome (isolate Pb01) (https://dna.biomol.unb.br/Pb/), as well as with all public ESTs available at GenBank, including sequences of the P. brasiliensis yeast-phase transcriptome (isolate Pb18) (http:// www.ncbi.nlm.nih.gov/). The focus was on the overexpressed and novel genes. From the total, 3184 ESTs (64.53 %) were also present in the previously described transcriptome of yeast-form and mycelium cells obtained from in vitro cultures (https://dna.biomol.unb.br/Pb/) and of those, 1172 ESTs (23.75 % of the described sequences) represented transcripts overexpressed during the infection process. Comparative analysis identified 1750 ESTs (35.47 % of the total), comprising 649 UniGene sequences representing novel transcripts of P. brasiliensis, not previously described for this isolate or for other isolates in public databases. KEGG pathway mapping showed that the novel and overexpressed transcripts represented standard metabolic pathways, including glycolysis, amino acid biosynthesis, lipid and sterol metabolism. The unique and divergent representation of transcripts in the cDNA library of yeast cells recovered from infected mice suggests differential gene expression in response to the host milieu.Abbreviations: EST, expressed sequence tag; KEGG, Kyoto Encyclopedia of Gene and Genomes; sqRT-PCR, semiquantitative RT-PCR.3These authors contributed equally to this work.The GenBank/EMBL/DDBJ accession numbers for the ESTs of Paracoccidioides brasiliensis identified in this study are EST1487-EST6420.Two supplementary tables listing the overexpressed and novel genes identified during this study and supplementary material describing the EST dataset analysed are available with the online version of this paper. Microbiology

Fifteen Paracoccidioides brasiliensis isolates were discriminated by the RAPD analysis into two groups with only 17% of genomic identity. The ability of P. brasiliensis isolates to invade tissues was studied in an experimental model using susceptible B10.A mice. The analysis was performed according to the severity of the lesions including the number and size of the granuloma, the number and dissemination of fungi to different organs. The isolates from two RAPD groups demonstrated a marked difference in their virulence patterns for B10.A mice. The isolates Pb S, 662, Bt and 166 (group I) elicited localized infection restricted to the liver showing compact epithelioid granuloma with few fungi in the early post-infection period (slightly virulent). On the other hand the isolates Pb 01 and 7455 (group II) elicited a disseminated infection with a mixed suppurative and looser granulomatous inflammation, showing extensive areas of necrosis and large numbers of viable fungal cells (highly virulent). These results are strong evidence for correlation between RAPD patterns and the virulence degree of P. brasiliensis.

No abstract

Fifteen Paracoccidioides brasiliensis isolates were discriminated by the RAPD analysis into two groups with only 17% of genomic identity. The ability of P. brasiliensis isolates to invade tissues was studied in an experimental model using susceptible B10.A mice. The analysis was performed according to the severity of the lesions including the number and size of the granuloma, the number and dissemination of fungi to different organs. The isolates from two RAPD groups demonstrated a marked difference in their virulence patterns for B10.A mice. The isolates Pb S, 662, Bt and 166 (group I) elicited localized infection restricted to the liver showing compact epithelioid granuloma with few fungi in the early post‐infection period (slightly virulent). On the other hand the isolates Pb 01 and 7455 (group II) elicited a disseminated infection with a mixed suppurative and looser granulomatous inflammation, showing extensive areas of necrosis and large numbers of viable fungal cells (highly virulent). These results are strong evidence for correlation between RAPD patterns and the virulence degree of P. brasiliensis.