Bacteriophages are incredibly diverse and widespread viruses that constantly threaten bacteria. The continuing coevolutionary fight between bacteria and their viral predators has resulted in the development of sophisticated and diverse array of bacterial defense mechanisms such as well known restriction-modification and CRISPR-Cas systems. Discovery of these systems led to the development of precise molecular tools used in genetic engineering and genome manipulation, thus the identification of novel defense systems may result in the development of new tools for manipulating cells and genomes. On the basis of the discovery that anti-phage defense systems frequently form so-called "defence islands" in bacterial genomes, several groups have employed computational methods to detect new uncharacterized defense systems [1, 2].
Here, we present research of nine of these newly discovered systems which have well known nuclease, NTPase and DNA/RNA helicase domains. We showed that these systems are active and possess resistence against bacteriophages. Also, we succesfully cloned these systems into high-copy plasmid DNAs and showed protein expression studies.