ECOFECT


Forum infectiologie du CIRI avec le Pr. Jean-Michel Claverie : Giant viruses !

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le 24 septembre 2015 /

Le Pr. Jean-Michel Claverie, Directeur du laboratoire Information Génomique et Structurale (UMR 7256) et Directeur de l’Institut de Microbiologie de la Méditerranée, donnera une conférence sur les virus géants le 24 septembre à 11h dans la salle des thèses Chantal Rabourdin-Combes de l’ENS de Lyon (site Monod).

Résumé de la conférence
:
More than a century ago, the notion of "virus" was introduced to designate infectious agents invisible to the light microscope and capable of passing through "sterilizing" filters. In addition to their extremely small size, most viruses studied over the years also exhibited minimal genomes and gene contents, almost entirely relying on cell-encoded functions to multiply, as expected from absolute intracellular parasites. Unexpectedly, the last ten years have seen the discovery of 4 different families of eukaryotic "giant viruses" exhibiting particles of cellular dimensions as well as gene contents overlapping in size with that of bacteria and some parasitic eukaryotes. Although all presently known giant viruses have been isolated using Acanthamoeba as laboratory host, related members are now starting to be found in other protozoa, such as marine picoplankton species the population of which they regulate. Representatives of two families of giant viruses have been revived from a layer of Siberian permafrost radiocarbon dated from 30.000 years ago, raising concern that pathogenic viruses from long past epidemics might also remain infectious and resurface in circumpolar regions as a consequence of  global warming and industrial exploitations.
The unexpected abundance, ubiquity and diversity of giant viruses, as well as the alien nature of their gene contents deeply challenge conventional conceptions about the origin and evolution of all DNA viruses and raise the question of their evolutionary relationship with the 3 cellular domains forming today's Tree of Life, and possibly other long extinct cellular lineages.

A propos de Jean-Michel Claverie : http://www.igs.cnrs-mrs.fr/spip.php?rubrique60

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