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:156-2</font></em></font></strong></font></td></tr><tr><td colspan=2><br><br><table align=center width=700><tr><td><b>Oral / Poster</b><br><table width="100%"><tr><td width="60">156-2</td><td><b>PbHAD32 participates in the adherence of <i>Paracoccidioides brasiliensis</i> conidia to epithelial lung cells</b></td></tr><tr><td valign=top>Authors:</td><td>Orville Hernandez (UDEA - Biology InstituteBCM - CIB - Cellular and Molecular Biology Unit) ; Agostinho J. Almeida (ICVS - Life and Health Sciences Research Institute) ; Diana Tamayo (UDEA - Biology InstituteBCM - CIB - Cellular and Molecular Biology Unit) ; Isaura Torres (UDEA - Biology InstituteBCM - CIB - Cellular and Molecular Biology Unit) ; Ana Maria Garcia (BCM - CIB - Cellular and Molecular Biology Unit) ; Angela Lopez (UDEA - School of Medicine) ; Angela Restrepo (MEM-CIB - Medical and Experimental Mycology Group) ; <u>Juan G. Mcewen </u> (BCM - CIB - Cellular and Molecular Biology UnitUDEA - School of Medicine) </td></tr></table><p align=justify><b><font size=2>Abstract</font></b><p align=justify class=tres><font size=2>The adhesion process of the dimorphic pathogenic fungus <i>P. brasiliensis</i> to pulmonary epithelial cells is considered an essential event for the establishment of an effective infectious process. If the process of adhesion is prevented the virulence of the <i>P. brasiliensis</i> isolate decrease. Previously, we showed that the hydrolase PbHAD32 is important for the adherence and virulence of <i>P. brasiliensis</i> in its pathogenic yeast form. In this study we generated <i>P. brasiliensis</i> conidia cells with down regulation in PbHAD32 gene expression, in orfer to further elucidate the role of this protein, specifically in the context of conidial thermo-dimorphism and interaction with epithelial cells. PbHAD32 gene expression profile analysis revealed increased mRNA levels during the conidia to mycelia (C-M) germination when we compared the conidia to yeast (C-Y) transition. Moreover, PbHAD32 is consistently expressed at higher levels upon infection of epithelial cells, but to a greater extent in conidia germinating to mycelia. Interestingly, conidia germinating to mycelia have a greater capacity to adhere to epithelial cells than conidia transiting to the yeast form. Altogether, our data not only corroborate the importance of this 32-KDa protein during initial adherence to host cells, but also demonstrate that this hydrolase may play a distinct role, or at least participate at different moments during the C-M and C-Y processes. The present study allow us to understand better the mechanism of infection in the pathogenic fungus, <i>P. brasiliensis</i>, and the possible role of this gene in the dissemination of the fungus. Acknowledgement: Colciencias (project No 221334319183), Corporacion para Investigaciones Biologicas and Universidad de Antioquia supported this work. The National Doctoral Program of COLCIENCIAS supported Orville Hernandez..</font></p><br><b>Keyword: </b>&nbsp;P. brasiliensis, Hydrolase, Adhesion, Virulence</td></tr></table></tr></td></table></body></html>