1. Department of Microbiology Institute of Biological Science Federal University of Minas Gerais P.O. Box 486 Belo Horizonte MG CEP 31270‐901 Brazil
2. Natural Products Utilization Research Unit United States Department of Agriculture, Agricultural Research Service University Oxford MS 38677 USA
3. National Center for Natural Products Research School of Pharmacy The University of Mississippi University Oxford MS 38677 USA
4. Center for Water and Wetland Resources The University of Mississippi Abbeville MS 38601 USA
5. Geosystems Research Institute Mississippi State University Starkville MS 39762 USA