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:100-1</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">100-1</td><td><b>The use of proteomics to study host-Paracoccidioides brasiliensis interactions </b></td></tr><tr><td valign=top>Authors:</td><td><u>Celia Maria de Almeida Soares Soares </u> (UFG - Universidade Federal de Goias) </td></tr></table><p align=justify><b><font size=2>Abstract</font></b><p align=justify class=tres><font size=2><b>The use of proteomics to study host-<i>Paracoccidioides brasiliensis</i> interactions</b> Celia Maria de Almeida Soares, Laboratorio de Biologia Molecular, Instituto de Ciencias Biologicas, Universidade Federal de Goias, Goiania, Goias, Brazil. email:cmasoares@gmail.com <i>Paracoccidioides brasiliensis</i> is a dimorphic fungal pathogen that causes pulmonary and systemic disease in humans. Two-dimensional electrophoresis in combination with mass spectrometry has become a powerful tool for studying the proteome of a number of pathogens. For fungi such as <i>P. brasiliensis</i> such information is nascent. We have addressed an important aspect of the <i>P. brasiliensis</i> interplay with the host: the influence of iron availability on the fungal metabolic processes. Iron acquisition is critical to cellular function and survival. During infection of mammals, the host limits the access of iron to microbial pathogens by a variety of means. We demonstrated an increased fungal burden in mice treated with iron supplement, indicating that iron availability promotes an increased susceptibility of mice to <i>P. brasiliensis</i> infection. The proteome of <i>P. brasiliensis</i> during iron starvation revealed a remodeling in energy metabolism increasing glycolytic activity , compensating the decrease of aerobic pathways that are mostly iron dependent. Putative virulence factors are induced upon iron deficiency. Genes induced by iron deficiency are also regulated in fungal cells during infection. Regulation of iron uptake and iron source preference has been investigated by our group. Both the reductive and siderophore iron uptake systems are found in <i>P. brasiliensis</i>. Upon iron deficiency it was observed the secretion of hydroxamate siderophores; reverse-phase HPLC analysis revealed dimerum acid in this fungi. <i>P. brasiliensis</i> can grow in the presence of hemoglobin as iron source; a cell surface protein, member of a putative hemoglobin-receptor gene family, was induced in the presence of hemoglobin and had been characterized as a GPI anchored protein. Overall our results indicate that <i>P. brasiliensis</i> utilizes iron sources within the host and requires reductive and non-reductive iron uptake systems. Proteomic analysis of yeast cells in the presence of hemoglobin is under progress. Financial support: FINEP, CNPq, FAPEG. </font></p><br><b>Keyword: </b>&nbsp;Paracoccidioides brasiliensis, iron metabolism, proteome, siderophores, iron sources</td></tr></table></tr></td></table></body></html>