a hairpin loop from a pre-mrna. highlighted are the nucleobases (green) and the ribose-phosphate backbone (blue). note that this is a single strand of rna that folds back upon itself. credit: vossman/ wikipediaresearchers led by martin jinek of the university of zurich have found an unprecedented mechanism by which bacteria defend themselves against invading viruses. when the bacterial immune system gets overwhelmed, the crispr-cas system produces a chemical signal that activates a second enzyme which helps in degrading the invaders' genetic material. this process is very similar to an antiviral mechanism of the human innate immune system. the crispr-cas system is an immune system that is found in many bacteria. it provides protection from viruses and other molecular parasites that can invade the bacterium and take over its genome. in these systems, the immunity is mediated by a complex multi-protein molecular machinery that uses rna molecules as molecular guides to recognize the invader and target it for destruction. until now, it has been known that the complex itself has nuclease activity – it can directly degrade the dna and rna of the invading viruses. now, an international research team headed by martin jinek of the university of zurich has found a new mechanism by which the invaders get destroyed.signaling molecule activates additional anti-viral enzymethe targeti...