1. Department of General Pathology, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil
2. Department of Biological Sciences, Kent State University at Stark, North Canton, OH 44720, USA
3. Department of Biology, The Catholic University of America, Washington, DC 20064, USA
4. Division of Mathematics and Sciences, Walsh University, North Canton, OH 44720, USA