PubMed Highlight: A new type of viruses, the Pandoraviruses.

Pandoraviruses: Amoeba Viruses with Genomes Up to 2.5 Mb Reaching That of Parasitic Eukaryotes

1. Nadège Philippe1,2,*, 
2. Matthieu Legendre1,*, 
3. Gabriel Doutre1, 
4. Yohann Couté3, 
5. Olivier Poirot1, 
6. Magali Lescot1,
7. Defne Arslan1, 
8. Virginie Seltzer1, 
9. Lionel Bertaux1, 
10. Christophe Bruley3, 
11. Jérome Garin3, 
12. Jean-Michel Claverie1,†,
13. Chantal Abergel1,†

Abstract:

Ten years ago, the discovery of Mimivirus, a virus infecting Acanthamoeba, initiated a reappraisal of the upper limits of the viral world, both in terms of particle size (>0.7 micrometers) and genome complexity (>1000 genes), dimensions typical of parasitic bacteria. The diversity of these giant viruses (the Megaviridae) was assessed by sampling a variety of aquatic environments and their associated sediments worldwide. We report the isolation of two giant viruses, one off the coast of central Chile, the other from a freshwater pond near Melbourne (Australia), without morphological or genomic resemblance to any previously defined virus families. Their micrometer-sized ovoid particles contain DNA genomes of at least 2.5 and 1.9 megabases, respectively. These viruses are the first members of the proposed “Pandoravirus” genus, a term reflecting their lack of similarity with previously described microorganisms and the surprises expected from their future study.