Scientists engineer suicide bomber bacteria to kill other bacteria

By ED YONG - NOT EXACTLY ROCKET SCIENCE
Added: Tue, 16 Aug 2011 17:18:10 UTC

In a lab in Singapore, scientists are designing and breeding suicide bombers. If their efforts pan out, they will be applauded rather than jailed, for their targets are neither humans nor buildings. They’re bacteria.

Nazanin Saeidi and Choon Kit Wong have found a new way of killing Pseudomonas aeruginosa, an opportunistic species that thrives wherever humans are weak. It commonly infects hospital patients whose immune systems have taken a hit. It targets any tissue it can get a foothold on – lungs, bladders, guts – and it often causes fatal infections. To seek and destroy this threat, Saiedi and Wong have used the common lab bacterium Escherichia coli as a sacrificial pawn.

Their E.coli recruits produce a protein called LasR, which recognises molecules that P.aeruginosa cells use to communicate with one another. When LasR detects to these chemical signals, it switches on two genes. The first one arms the bomb. It produces pyocin, a toxin that kills P.aeruginosa by drilling through its outer wall and causing its innards to leak out. The second gene detonates the bomb. It produces a protein that causes the E.coli to burst apart, killing itself but also releasing a flood of deadly pyocin upon nearby P.aeruginosa.