Even Viruses Catch Viruses

[n2doc]

By Jason Socrates Bardi, Inside Science News Service


Among pathogens, viruses are unique in their collective ability to infect all types of organisms. There are plant viruses, insect viruses, fungal viruses, and even viruses that infect only amoeba and bacteria. Now a group of researchers at the Centre National de la Recherche Scientifique in France has made the startling discovery that even some viruses can have viruses.

In a paper in Nature last month, the group described how they identified a giant mimivirus in a cooling tower in France. Mimiviruses are the largest viruses known to exist — so big they are visible under a normal optical microscope (usually much higher resolution electron microscopes are needed to view them). The new virus, large even by mimivirus standards, was appropriately named "mamavirus."

In the same cooling tower, the French group also discovered a second, tiny virus that infects the giant mamavirus. This they named "Sputnik."

Sputnik is unusual because it is the first virus ever discovered that is a parasite of another virus. When it reproduces in a cell infected by the larger virus, its action impairs the reproduction of mamavirus particles. The group sequenced Sputnik's genetic code and discovered that a number of its gene sequences are similar to those found in a massive survey of genetic material taken from oceans all over the globe. This suggests that a whole class of viruses might exist that infect other viruses.

Moreover, the discovery rekindles the debate over whether viruses are alive. Viruses are often not considered living organisms because they lack their own cellular structure and the ability to metabolize food — traits common to all known forms of life. The ability of one virus to infect another calls into question the possibility that viruses should be considered forms of life — though this is no great revelation for some.

more:
http://www.livescience.com/strangenews/080928-virus-viruses.html

[TomInTib]

1. What's your take on the theory that some viruses cause some cancers?

I am no medical professional, but from what I have seen and read, I believe it.

[pokerfan]

3. I wasn't aware that this was even a controversy

http://www.medicalnewstoday.com/articles/3988.php">How virus causes cancer (Medical News Today)
http://www.sciam.com/article.cfm?id=kill-the-virus-stop-the-cancer">Kill the Virus, Stop the Cancer (Scientific American)

[TomInTib]

5. Thanks.

I don't get out, much.

I thank you for sending those links to me.

Tom

[kestrel91316]

4. Feline leukemia virus, one of the feline retroviruses, has been known

for decades to cause many different cancers in cats. Of note are leukemia (obviously) and lymphoma.

Rous sarcoma virus in chickens.

The virus that causes infectious mononucleosis also causes Burkitt's lymphoma in African children.

Bovine leukemia virus (grasping into the depths of my memory here....).

Some others......IIRC

[BrklynLiberal]

2. That is interesting stuff.... Thanks for posting.

[nam78_two]

6. On a related note, can mycoplasma infect other prokaryotes?

I know mycoplasma can infect eukaryotes, but I have this vague memory of either hearing this from someone or attending a seminar where someone talked about mycoplasma infecting some species of pathogenic e.coli-but I could not find a reference to it so maybe it was just a dream I had or something.