1. Department of Microbial Natural Products, Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI) and Pharmaceutical Biotechnology, Saarland University, Campus C2 3, 66123 Saarbrücken, Germany, and Department of Genetics and Biotechnology, Ivan Franko National University of L’viv, Grushevskogo st. 4, L’viv 79005, Ukraine