From Ewen Callaway at Nature:
A virus that infects bacteria listens to messages from its relatives when deciding how to attack its hosts.
Its relatives? These aren’t the viruses we learned about in health and safety class.
The discovery — in viruses that attack Bacillus bacteria — marks the first time that any type of viral communication system has ever been found. But researchers say that many other viruses could communicate with each other through their own molecular languages — perhaps even viruses that are responsible for human diseases. If that is the case, scientists might have found a new way to disrupt viral attacks.
When levels of arbitrium build up — after a large number of cells have died — phages stop killing off the remaining bacteria and retreat to lie dormant in bacterial genomes instead. Sorek, Erez and their colleagues identified two further phi3T proteins that measure levels of arbitrium and then influence the nature of subsequent infections.
“It does make a lot of sense,” says Peter Fineran, a microbial geneticist at the University of Otago in Dunedin, New Zealand. “If the phage is running out of hosts, it would try and limit its destruction, and sit quiet and wait for the host to re-establish growth.” More.
It would make sense that the virus would try to survive if it is the sort of entity that experiences any pressure to do so. That is a key quality that distinguishes life from non-life. Or, to put it another way, rocks do not try to prevent themselves from becoming sand.
It seems harder than ever to argue that viruses are not a life form.
And information seems more and more what life is mainly about.
See also: Why “evolution” is changing? Consider viruses
The Scientist asks, Should giant viruses be the fourth domain of life? Eukaryotes, prokaryotes, archaea… and viruses?
Are viruses nature’s perfect machine? Or alive?
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