1. Department of Chemistry, University of Alabama in Huntsville, Huntsville, Alabama 35899, USA
2. Missouri Botanical Garden, St. Louis, Missouri 63166, USA Apdo. 50–5655, Monteverde, Puntarenas, Costa Rica
3. Tropical Disease Research Unit, Department of Pathology, University of California San Francisco, VAMC, 4150 Clement Street-113B, San Francisco, California 94121, USA