RSS: person:jean-michel claverie

person:jean-michel claverie

  • @nautilus
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    Here’s How to Make Climate Change Extra Scary - Facts So Romantic
    ▻http://nautil.us/blog/heres-how-to-make-climate-change-extra-scary

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    Thirty thousand years ago, a woolly mammoth in Siberia shed a giant virus. It soon became encased in ice and, for tens of thousands of years, the virus slept. As global temperatures warm and the permafrost begins to melt, the virus stirs. It is sucked into the nostril of a researcher where it injects its DNA into a cell. The DNA commandeers the cell’s proteins and generates new viruses, turning the researcher into a walking pathogen factory. As she interacts with people, the virus swarms around the world, infecting millions and causing devastation on a massive scale.Alex Tihonov/Getty Images Such a scenario isn’t yet a reality, but it may be closer than you think. Jean-Michel Claverie, a microbiologist at Aix-Marseilles University in Provence, could have caused this scenario twice. In (...)

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  • @simplicissimus
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    Un nouveau virus géant, âgé de plus de 30 000 ans, découvert en Sibérie
    ▻http://www.lemonde.fr/sciences/article/2014/03/04/un-nouveau-virus-geant-age-de-plus-de-30-000-ans-decouvert-en-siberie_437701

    Un nouveau type de virus géant a survécu plus de 30 000 ans à la congélation, dans une couche de permafrost sibérien contemporaine de l’extinction de l’homme de Neandertal, selon une étude publiée dans les comptes rendus de l’académie des sciences américaines, les PNAS, lundi 2 mars.
    (…)
    Hormis la fonte des glaces, susceptible de libérer des pathogènes, la région de Chukotka, d’où provient ce virus géant, abrite en effet de grandes réserves de pétrole, de gaz naturel, de charbon, d’or et de tungstène. « En creusant pour trouver du pétrole ou du gaz, des hommes pourront bien involontairement entrer en contact avec des microbes, (...) être contaminés et devenir des vecteurs », disent aussi les chercheurs dans Le Figaro.

    La possibilité d’une réémergence de virus considérés comme éradiqués à partir de ce grand frigo qu’est le permafrost ne relève donc plus d’un scénario de science-fiction, estime M. Claverie. Celui de la variole par exemple, qui a sévi jadis en Sibérie, se multiplie de façon similaire aux Pithovirus, et pourrait toujours exister sous terre. Récemment, c’est un nouveau parasite protozoaire séquéstré par la glace qui a émergé, selon Le Figaro, et a affecté otaries, morses et ours de l’Arctique au Canada.

    #Tchoukotka

    Simplicissimus
    • @simplicissimus
      Simplicissimus

      Dans Nature

      Giant virus resurrected from 30,000-year-old ice : Nature News & Comment
      ▻http://www.nature.com/news/giant-virus-resurrected-from-30-000-year-old-ice-1.14801

      Evolutionary biologists Jean-Michel Claverie and Chantal Abergel, the husband-and-wife team at Aix-Marseille University in France who led the work, named it Pithovirus sibericum, inspired by the Greek word ’pithos’ for the large container used by the ancient Greeks to store wine and food. “We’re French, so we had to put wine in the story,” says Claverie.

      http://www.nature.com/polopoly_fs/7.15843.1393867609!/image/1.14801.jpg_gen/derivatives/landscape_630/1.14801.jpg

      Pithovirus has a ‘cork’ with a honeycomb structure capping its opening (see electron-microscope image). It copies itself by building replication ‘factories’ in its host’s cytoplasm, rather than by taking over the nucleus, as most viruses do. Only one-third of its proteins bear any similarity to those of other viruses. And, to the team’s surprise, its genome is much smaller than those of the Pandoraviruses, despite its larger size.

      “That huge particle is basically empty,” says Claverie. “We thought it was a property of viruses that they pack DNA extremely tightly into the smallest particle possible, but this guy is 150 times less compacted than any bacteriophage [viruses that infect bacteria]. We don’t understand anything anymore!”

      Although giant viruses almost always target amoebae, Christelle Desnues, a virologist at the French National Centre for Scientific Research in Marseilles, last year discovered5 signs that another giant virus, Marseillevirus, had infected an 11-month-old boy.

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