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:92-2</font></em></font></strong></font></td></tr><tr><td colspan=2><br><br><table align=center width=700><tr><td><b>Investigação</b><br><table width="100%"><tr><td width="60">92-2</td><td><b>Presence and expression of the Mating Type locus in Paracoccidioides brasiliensis isolates.</b></td></tr><tr><td valign=top>Authors:</td><td><u>Isaura Torres Gomez </u> (BCM, CIB - Cellular and Molecular Biology Unit, CIB, Medellin, ColombiaU DE A, MEDELLIN, CO - Biology Institute) ; Juan G Mcewen (BCM, CIB - Cellular and Molecular Biology Unit, CIB, Medellin, ColombiaU DE A, MEDELLIN, CO - Facultad de Medicina, U de Antioquia, Medellin, Colombia) ; Angela Restrepo (BCM, CIB - Cellular and Molecular Biology Unit, CIB, Medellin, Colombia) ; Myrta Arango (BCM, CIB - Cellular and Molecular Biology Unit, CIB, Medellin, ColombiaU DE A, MEDELLIN, CO - Facultad de Medicina, U de Antioquia, Medellin, Colombia) </td></tr></table><p align=justify><b><font size=2>Abstract</font></b><p align=justify class=tres><font size=2>In fungi, sexual reproduction is regulated by a group of genes known as the Mating Type locus (MAT 1). In Paracoccidioides brasiliensis<i>text</i>, an important human pathogen, sexual reproduction has not been demonstrated and consequently, its implications in fungal taxonomy and virulence remain undefined. In this work, the presence of both MAT 1 genes (MAT1-1 and MAT1-2) in a group of 71 P. brasiliensis isolates from diverse sources was ascertained: in some, the MAT 1 gene activity was determined by measuring the corresponding expression by qPCR. Additionally, a number of outcrosses among compatible isolates were explored. We found two heterothallic groups, one carrying a MAT1-1 gen and another carrying a MAT1-2 gene. These populations were in a 1:1 ratio with basal gene expression being detected for certain of these genes, indicating that the mating process could be feasible. Some of the crosses performed on special culture media displayed a number of structures resembling fruiting bodies, although they did not contain the expected reproductive structures (asci and ascospores) corresponding to the Ascomycota phylum. Demonstration of the presence of the MAT1-1 and MAT1-2 genes in P. brasiliensis<i>text</i> has provided new tools for the study of sexual reproduction in this fungus, leading to a better understanding of its biology both as a saprobe and as a pathogen, as well as to more precise taxonomic classification. Further studies should be conducted to confirm the sexual capacity of this fungus and its implications among phylogenetic species and geographical distribution. This work was supported by a grant from Banco de la República de Colombia, proyect No. 2.051 and counted with with the collaboration of Drs. Joseph Heitman and Wenjun Li from the Center for Microbial Pathogenesis, Department of Molecular Genetics and Microbiology (MGM), Duke University Medical Center, Durham, NC.</font></p><br><b>Keyword: </b>&nbsp;Paracoccidioides brasiliensis, Mating type, MAT 1-1, MAT1-2, Real time PCR</td></tr></table></tr></td></table></body></html>