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Viruses are world champion parasites—think of all the trouble they give us, from Ebola to HIV. Now French researchers have discovered a viral first … a virus that infects another virus.

A virus that scientists are calling Sputnik was found in a newly discovered strain of so-called mimivirus, which is the  world's largest known virus. Virologist Jean-Michel Claverie, of France's National Center for Scientific Research and a team from the University of the Mediterranean in Marseille, happened upon the strain of mimivirus swimming in the water of a Parisian cooling tower. When they peeked inside the viral particle, they discovered Sputnik, which consists of only 21 genes.

They found that mimiviruses infected with Sputnik are less effective at infecting amoebae, which is what they normally do.

The researchers believe that Sputnik is the first of a yet-to-be-discovered family of viruses that they suspect may plague large viruses that attack ocean plankton. The French team reported their findings in the new issue of Nature, out yesterday.

The finding may answer a long-standing debate posed upon a 2004 cover of Scientific American: Are viruses alive?

It’s a seemingly simple question, but actually not: On the one hand, viruses can copy themselves and affect the health and behavior of other organisms. But, they require the machinery of other organisms to do any of that.

But, according to Claverie, if mimivirus can both pirate another organism's DNA-copying machinery and fall prey to another virus that does the same to it, then mimivirus is most certainly alive.

"There’s no doubt this is a living organism," he told Nature News. "The fact that it can get sick makes it more alive."

(Photo: iStockphoto/Henrik Jonsson)

4 Comments

1. 1. matthewmazurek 10:57 AM 8/8/08

   According to the Helen Pearson article on Nature News ('Virophage' suggests viruses are alive: Evidence of illness enhances case for life. http://www.nature.com/news/2008/080806/full/454677a.html), the Sputnik virus was found associated with the mimivirus' larger cousin: the mamavirus.

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2. 2. DSmith1204 05:52 PM 8/8/08

   I thought that virusues (?viri), including mimiviruses, had no DNA for another virus such as Sputnik to use. Is Sputnik also using the DNA of the host, what's the big deal about being alive? What is the definition of being alive? Having DNA? Mitochondria have DNA, does that make them an alive entity, living parasitically inside our cells:
   David L. Smith MD

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3. 3. sijodk 02:16 PM 8/9/08

   So the mimivirus is alive because it can become infected by the sputnik virus. Does anything infect the latter and either way is it alive then?!?

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4. 4. Dov Henis 09:46 PM 8/10/08

   Are Viruses "Alive"?
   
   alive = organism:
   
   arth's organisms: temporary self-replicable constrained-energy genetic systems that support and maintain Earth's biosphere by maintenance of genes.
   
   Every "self-replicable" genetic system has a unique package of essentials for replication...and viruses are not different in this respect than other organisms.
   
   Dov Henis
   
   PS: 21st Century Life Comprehension
   
   1. Definitions Of Earth Life, Organism, Gene, Genome And Cellular Organisms.
   
   Earth Life: 1. a format of temporarily constrained energy, retained in temporary constrained genetic energy packages in forms of genes, genomes and organisms 2. a real virtual affair that pops in and out of existence in its matrix, which is the energy constrained in Earth's biosphere.
   
   Earth organism: a temporary self-replicable constrained-energy genetic system that supports and maintains Earth's biosphere by maintenance of genes.
   
   Gene: a primal Earth's organism.
   
   Genome: a multigenes organism consisting of a cooperative commune of its member genes.
   
   Cellular organisms: mono- or multi-celled earth organisms.
   
   
   2. Update of life sciences conceptions is now feasible and urgently desirable
   
   - Earth's biosphere phenomenon is a distant relative of black holes, a form of constrained
   energy pocket.
   
   - First were independent individual genes, Earth's primal organisms.
   
   - Genes aggregated cooperatively into genomes, multigenes organisms, with genomes' organs.
   
   - Simultaneously or consequently genomes evolved protective and functional membranes, organs.
   
   - Then followed cellular organisms, with a variety of outer-cell membranes shapes and
   functionalities.
   
   
   3. Nature, Origin, Function And Purpose Of Life
   
   
   Nature of Earth life: a replicating construction temporarily constraining and maintaining energy.
   
   Origin of Earth life: serendipitous energy-induced formation of Earth's primal organisms, individual independent genes.
   
   Nature of Earth's organisms: temporary self-replicable constrained-energy genetic systems that support and maintain Earth's biosphere by maintenance of genes.
   
   Function of Earth life: uphold and maintain as much constrained energy as possible by upholding and maintaining Earth's biosphere.
   
   The purpose of OUR life and its promotion is ours to choose and set. It derives solely from our cognition.
   
   
   Dov Henis
   
   http://blog.360.yahoo.com/blog-P81pQcU1dLBbHgtjQjxG_Q--?cq=1

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