1. State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, P. R. China
2. Helmholtz International Lab for Anti-Infectives, Shandong University, Qingdao 266237, P. R. China
3. Helmholtz International Laboratory, Department of Microbial Natural Products (MINS), Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus E8 1, 66123 Saarbrücken, Germany
4. Helmholtz International Lab for Anti-Infectives, Campus E8 1, 66123 Saarbrücken, Germany