1. Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093-0204, United States
2. Natural Products Laboratory, Worldwide Medicinal Chemistry, Pfizer Worldwide Research and Development, 558 Eastern Point Road, Groton, Connecticut 06340, United States
3. Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093, United States