SoylentNews

AnonTechie writes:

When they are not busy attacking us, germs go after each other. But when viruses invade bacteria, it doesn’t always spell disaster for the infected microbes: Sometimes viruses actually carry helpful genes that a bacterium can harness to, say, expand its diet or better attack its own hosts.

Scientists have assumed the bacterial version of an immune system would robotically destroy anything it recognized as invading viral genes. However, new experiments at Rockefeller University have now revealed that one variety of the bacterial immune system known as the CRISPR-Cas system can distinguish viral foe from friend. And, the researchers report in a paper published August 31 in Nature, it does so by watching for one particular cue.

“Transcription — an initial step in the process that reads genes, including those of viruses — makes the difference,” says researcher Luciano Marraffini, head of the Laboratory of Bacteriology. “The full genome of viruses in their lytic, or destructive phase, is transcribed. Meanwhile, only a few of the genes from a virus are transcribed during its lysogenic, or dormant phase.”

http://newswire.rockefeller.edu/2014/08/31/discovery-reveals-how-bacteria-distinguish-harmful-versus-helpful-viruses/

[Abstract]: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13637.html