All around the world ' in the oceans, the soil, your body ' an invisible battle is raging. Earth's vast population of roughly 1030 bacteria faces an unending onslaught from an even larger army of viruses, known as bacteriophages. The bacteria have a variety of defences at their disposal: they chop up viral components, deny the invaders key ingredients for replication and even shut down their own biological systems to halt infections, sacrificing themselves to protect nearby kin. The viruses, in turn, evolve counter-defence mechanisms, resulting in an ever-escalating arms race. Although microbiologists are just beginning to understand the extent of this eternal contest, microbial immune mechanisms have already inspired technologies that have revolutionized biology. The discovery of restriction enzymes, bacterial proteins that slice DNA at specific sites, sparked the field of molecular biology in the 1970s, enabling everything from the development of genetically modified organisms to...
learn more
