We study the interaction between bacteria and the viruses (phages) infecting them. Our goal is to gain fundamentally new insights into the bacterial immune system and to apply this knowledge for the development of innovative applications in synthetic biology and biotechnology. Furthermore, we are interested in the design and dynamics of complex regulatory networks enabling microorganisms to adapt to ever changing environments and to discriminate between ‘self’ and ‘foreign’. Microbial model hosts used in our laboratory include the biotechnological platform strain Corynebacterium glutamicum and Streptomyces – the source of most of our antibiotics.