ÿþ<HTML><HEAD><TITLE>XI International Meeting on Paracoccidioidomycosis</TITLE><link rel=STYLESHEET type=text/css href=css.css></HEAD><BODY aLink=#ff0000 bgColor=#FFFFFF leftMargin=0 link=#000000 text=#000000 topMargin=0 vLink=#000000 marginheight=0 marginwidth=0><table align=center width=700 cellpadding=0 cellspacing=0><tr><td align=left bgcolor=#cccccc valign=top width=550><font face=arial size=2><strong><font face=Verdana, Arial, Helvetica, sans-serif size=3><font size=1>XI International Meeting on Paracoccidioidomycosis</font></font></strong><font face=Verdana size=1><b><br></b></font><font face=Verdana, Arial,Helvetica, sans-serif size=1><strong> </strong></font></font></td><td align=right bgcolor=#cccccc valign=top width=150><font face=arial size=2><strong><font face=Verdana, Arial, Helvetica, sans-serif size=1><font size=1>Resume:142-2</font></em></font></strong></font></td></tr><tr><td colspan=2><br><br><table align=center width=700><tr><td><b>Poster (Painel)</b><br><table width="100%"><tr><td width="60">142-2</td><td><b>Mating aspects in Paracoccidioides</b></td></tr><tr><td valign=top>Authors:</td><td><u>Marcus Teixeira </u> (UNB - Universidade de Brasília) ; Raquel Cordeiro Theodoro (UNESP - Universidade Estadual Paulista) ; Lorena da Silveira Derengowsky (UNB - Universidade de Brasília) ; Walter Rosa do Amaral Júnior (UNB - Universidade de Brasília) ; Eduardo Bagagli (UNESP - Universidade Estadual Paulista) ; Maria Sueli Felipe (UNB - Universidade de Brasília) </td></tr></table><p align=justify><b><font size=2>Abstract</font></b><p align=justify class=tres><font size=2>The thermodimorphic fungi P. brasiliensis and P. lutzii are the etiological agents of Paracoccidioidomycosis (PCM). The phylogenetic classification of Paracoccidioides places it in the host-associated fungal pathogens family Ajellomycetaceae. The sexual stage is commonly observed among the members of this family however Paracoccidioides have been considered asexual. Split decomposition analysis revealed recombination networks within isolated populations in Paracoccidioides. Comparative genomic analysis using a repertoire of 209 known mating and meiotic regulators in fungi demonstrates the presence of conserved genes involved in the sexual reproduction, including the following classifications: &#945;-pheromone precursor gene, pheromone receptors, pheromone processing enzymes, mating signaling regulators, fruiting body development, karyogamy and meiosis. Also, a total of 98 isolates representing the P. brasiliensis species complex S1/PS2/PS3 and P. lutzii were amplified for the MAT locus exhibiting both homothallic and heterothallic profiles. 55 isolates possessed the MAT1-1 locus and 30 isolates possessed the MAT1-2 locus. Unexpectedly, 13 isolates presented both a MAT 1-1 and MAT1-2 amplified locus, indicating that homothallism could exist in the Paracoccidioides genus. Heterothallic MAT1-1, MAT1-2 and homothallic MAT1-1/MAT1-2 populations prevalence was 56%, 31% and 13%, respectively, which approximated the ratio 4:2:1. The expression of the sex-related genes in the yeast and mycelium phases was also detected by Real Time PCR, almost all of them preferentially more expressed in filamentous form. We tested the effect of pheromone stimulation by the conditioned medium (CM) of co-cultured T9B1 (MAT1-1) and T15LN1 (MAT1-2) strains. After 24 h of stimulation of mycelium the sex-related genes were quantified by real-time RT-PCR. All genes of the mating cascade were highly up-regulated after CM stimulation in T8B1 and T15LN1 strains growth alone, except for the pheromone receptor (ste3) in the T9B1 isolate, indicating an activation of the mating machinery by a and &#945;- pheromone molecules, probably due to its presence in the CM. Laboratorial crossings of different mating-type isolates led us to indentify young ascocarps formation with constricted coiled hypha related to the initial process of mating. Thus, genomic and morphological analysis strongly supports the hypothesis of existence of sexual cycle in Paracoccidioides. Funding: CNPq, FAP-DF</font></p><br><b>Keyword: </b>&nbsp;mating, pheromone, Paracoccidioides</td></tr></table></tr></td></table></body></html>