Researchers have identified a virus that is capable of “spying” on the molecular communications between bacteria – and now they’ve weaponized the ability so that the virus kills bacteria on command. This approach has been used by researchers to attack bacterial diseases like salmonella, cholera, and E. coli.
The work, published in the journal Cell, was conducted by Professor Bonnie Bassler and graduate student Justin Silpe from Princeton University. They discovered that the virus VP882 eavesdrops to make a binary choice: stay put or kill its bacterial host. Kill only happens if the virus knows that the bacteria is not alone, so that it can safely destroy the bacteria and move on to the next target.
“The idea that a virus is detecting a molecule that bacteria use for communication – that is brand-new,” explained Bassler in a statement. “
Princeton molecular biologist Bonnie Bassler and graduate student Justin Silpe have identified a virus, VP882, that can listen in on bacterial conversations — and then, in a twist like something out of a spy novel, they found a way to use that to make it attack bacterial diseases like E. coli and cholera.
“The idea that a virus is detecting a molecule that bacteria use for communication — that is brand-new,” said Bassler, the Squibb Professor of Molecular Biology. “Justin found this first naturally occurring case, and then he re-engineered that virus so that he can provide any sensory input he chooses, rather than the communication molecule, and then the virus kills on demand.” Their paper will appear in the Jan. 10 issue of the journal Cell.
A virus can only ever make one decision, Bassler said: Stay in the host or kill the host. That is, either remain under the radar inside its host or activate the kill sequence that creates hundreds or thousands of offspring that burst out, killing the current host and launching themselves toward new hosts.
There’s an inherent risk in choosing the kill option: “If there are no other hosts nearby, then the virus and all its kin just died,” she said. VP882 has found a way to take the risk out of the decision. It listens for the bacteria to announce that they are in a crowd, upping the chances that when the virus kills, the released viruses immediately encounter new hosts. “It’s brilliant and insidious!” said Bassler.
In the early experiments it looked like the virus called VP882 was doing something that should be impossible for a thing that is not a bacterium, and not technically even alive: intercepting molecular messages exchanged by its host bacteria, and reading them to determine the best time to annihilate the whole bacterial colony. “As scientists, this is just unimaginable to us,” says Bonnie Bassler, a molecular biologist at Princeton University. “We were delighted and skeptical at the same time. It was almost too good to be true.”
Not only did it turn out to be true for VP882; Bassler learned there is a family of bacteria-infecting viruses (a subgroup of a kind called bacteriophages, or just “phages”) that eavesdrop on their hosts’ routine molecular communications with other bacteria. That means VP882’s kill trigger could be easily manipulated to target any bacteria, Bassler says—opening the possibility that the virus could be engineered into an ideal killing machine for dangerous pathogens.
h/t Digital mix guy