1. Gause Institute of New Antibiotics, Russian Academy of Medical Sciences, B. Pirogovskaya 11, Moscow, 119867 Russia, Advanced Medicine East, 8 Cedar Brook Drive, Cranbury, New Jersey 08512, and NMR Laboratory, Research Group of Antibiotics of the Hungarian Academy of Sciences, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, P.O. Box 70, Hungary