**Acknowledgment**

Hueder Paulo Moisés de Oliveira thanks to the financial support propitiated by FAPESP (Project of research support 06/56701-3) and to CNPq to the research grants (479655/2008-1). Thanks to Msc Sandra Cruz dos Santos and Luiza Rosimeri Romano Santin to the revisions. Thanks also FFCLRP-USP, Prof. Amando Siuiti Ito´s laboratory.

The author Máira Regina Rodrigues thanks CNPq and FAPESP for the financial support.
