1. Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
2. Helmholtz-Institute for Pharmaceutical Research Saarland, Helmholtz Center for Infectious Research, Department of Microbial Natural Products, Saarland University, Campus C2 3, 66123 Saarbrücken, Germany