Mimi's Mama Meets Sputnik

In 1992, T.J. Rowbotham et al. isolated an amoeba-infecting virus that was so large, his team first thought it to be a bacterium; after positive identification as an icosahedral DNA virus in 2003 (La Scola et al.), this pathogen was named Mimicking Microbe virus because it's susceptibility to staining, inability to pass through ultrafine filters, and confusingly large size (~650nm naked capsid). Mimivirus was then given it's own family, to which a few other members have since been added.

One notable addition, Mamavirus, which is actually considered to be even larger than Mimivirus, has led to the startling discovery of a large virophage. Yes, even viruses have their own parasites that are detrimental to their own reproductive success. A satellite virus, named Sputnik, was found in Mama's cytoplasm by La Scola et al. in 2008, and this finding has brought up questions regarding whether or not viruses can be alive; can non-living organisms be parasitized? Virologist Jean-Michel Claverie says, vehemently, "There's no doubt this is a living organism," and he and Eugene Koonin suggest that the further blurring of divisions between 'living' and 'nonliving' that comes with these new discoveries means the 'imaginary line' between viruses and cellular organisms should be erased. There still are a lot of viruses out there (esp. in the ocean) than can change our thinking about the organism as a whole.

Suggestion for naming the next big virus: MOABviridae (Mother of All Big Viruses)

----------Nguyen---------------

1. The virophage as a unique parasite of the giant mimivirus - 2008

http://www.nature.com/nature/journal/v455/n7209/full/nature07218.html

2. Genomic and evolutionary aspects of Mimivirus -2006
http://www.sciencedirect.com/science/article/pii/S0168170205002376

3. 'Virophage' suggest viruses are alive - 2008

http://www.igs.cnrs-mrs.fr/SpipInternet/IMG/pdf/PearsonNatureNews.pdf