A bacterial alarm that works backwards: the cell that destroys itself only after the virus arrives

Bacteria have immune systems too — and one of them appears to run in reverse. Scientists at the Gladstone Institutes have described a defence called a type VI retron, published in Molecular Cell, that idles quietly in an uninfected cell, making almost none of its DNA trigger. Only after a virus strikes does production surge — unlocking a toxin that kills the infected cell and stops the virus spreading to its neighbours. The team needed a new recording method, Spacer-seq, even to see the faint pre-infection signal previous tools had missed. It is basic biology with a twist ending — and a new switch that biotechnology may one day borrow.

SDG 9 · Industry, innovation and infrastructure — Mechanism: tech innovation