1. Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Beutenbergstr. 11a, D-07745 Jena, Germany, Oncotest GmbH, Institut für Experimentelle Onkologie, Am Flughafen 12-14, D-79108 Freiburg, Germany, and The Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan Institute of Microbiology, Yunnan University, Kunming 650091, China