A Virus That Saves Itself By Preventing Bacterial Suicide

By Ashley P. Taylor | November 15, 2012 3:39 pm

spacing is important
Electron micrograph of bacteria-infecting viruses

Bacteria sometimes commit suicide for the good of the group. When a virus infects a bacterium, the cell kills itself rather than allow the virus to replicate inside it and spread to the surrounding bacteria.

The way this works is that when viruses aren’t around, the bacteria manufacture both a bacterial cyanide pill—a toxin molecule they could use to wipe themselves out if they come under attack—and an antitoxin molecule that keeps the toxin in check. When a virus infects the bacterium, the toxin is released, kills the bacterial cell, and prevents the virus from spreading to other cells. It’s bad for the individual bacterial cell but good for the community—and certainly bad for the infecting virus. Now researchers have found a virus that manipulates this mechanism for its own means, saving itself by keeping its host bacteria from cellular suicide.

This particular virus, called ΦTE, is normally vulnerable to this defense. But researchers have found some mutants of ΦTE  that manage to beat the system. These mutants produce their own version of the antitoxin molecule, preventing suicide of the bacterial host. Though other viruses have come up with ways to avoid these bacterial suicide systems, researcher George Salmond says, as far as he knows, this is the first virus to do so by mimicking a bacterium’s antitoxin. By keeping one cell alive, the virus goes on to attack the entire population.

Bacteriophage image via Graham Beards

CATEGORIZED UNDER: Health & Medicine, Living World
  • R. J. Redfield

    Nice just-so story…

  • j.michael carney

    Researching lyme disease has lead down many paths , A Dr of biology was my best find Dr Emma Allen passed a few years ago at 90 but her insight gave me hope that you can still live a fairly normal life with lyme. This bacteria / virus insight has been a thought of mine in a way to attack lyme without killing our selves with antibiotics. If we could find a virus that could attack lyme ,we could have a cure. Hopeful thinking . I’m sure some madd scientist is working on the cure using Buckyballs ( THE GREY GOO ) is at our door step!!!

  • BanFrenchRoast

    Interesting from an evolutionary point of view. The non-survival of the individual cell promotes the endurance of the population, the members of which go on to pass down the gene(s). I suppose this is not too amazing in that mulch-cellular organism rely on this kind of cellular behavior in order to be viable. Still it is a good reminder that direct genetic survival and transmission is not the only kind that counts. There may be supporting players as well. Also we should remember that “gene” in an evolutionary sense is more like the “classical” definition of a gene as the “unit of inheritable trait” rather than encoding a specific protein. It includes all the control logic that goes with gene expression, formerly known as the contribution of “junk DNA”.


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