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New giant virus discovered

Scientists have discovered a new family of giant viruses -- created within amoebae, they linkurl:report;http://www.pnas.org/cgi/doi/10.1073/pnas.0911354106 in this week's issue of the Proceedings of the National Academy of Sciences. Structural analysis of giant virus Image: Xiao C, Kuznetsov YG, Sun S, Hafenstein SL, Kostyuchenko VA, et al. (2009) The new virus type is uniquely comprised of genes from a variety of origins, including bacteria, eukaryotes and viruses. Amoebae are not an uncomm

By | December 7, 2009

Scientists have discovered a new family of giant viruses -- created within amoebae, they linkurl:report;http://www.pnas.org/cgi/doi/10.1073/pnas.0911354106 in this week's issue of the Proceedings of the National Academy of Sciences.
Structural analysis of giant virus
Image: Xiao C, Kuznetsov YG, Sun S, Hafenstein
SL, Kostyuchenko VA, et al. (2009)
The new virus type is uniquely comprised of genes from a variety of origins, including bacteria, eukaryotes and viruses. Amoebae are not an uncommon source of viruses, since their insides are melting pots of viruses and other organisms, allowing viruses to grow into so-called "giants" by adopting genes from other organisms within the amoebae. "Researchers have recognized the potential of amoebae as a source of new viruses for a while," said linkurl:Patrick Forterre,;http://www.pasteur.fr/ip/easysite/go/03b-00002i-01l/recherche/departements-scientifiques/microbiologie/unites-et-groupes/unite-de-biologie-moleculaire-du-gene-chez-les-extremophiles/les-membres-de-l-equipe/patrick-forterre a microbiologist at the Pasteur Institute in Paris, France, who was not involved with the study. "But [this paper] is the first real confirmation that [other giant viruses found in amoebae are] not an exception... It also means there might be a huge number of diverse giant viruses in amoebae that haven't been discovered yet." Giant viruses were first discovered in the late 1990s, and are characterized by their large particle sizes, typically bigger than 200 nanometers, and genetic complexity. (Medium-sized viruses such as adenovirus and HIV measure closer to 100-200 nm.) This newest giant virus was discovered by linkurl:Didier Raoult;http://www.antimicrobe.org/authors/didier_raoult.asp and colleagues the Universite de la Mediterranee in Marseille, France. The scientists isolated the new virus, named Marseillevirus, from Acanthamoeba polyphaga. Phylogenetic analysis of the Marseillevirus revealed several genetic similarities to other giant viruses. It also carries genes obtained from eukaryotic hosts and their parasites or symbionts. "Other viruses are commonly alone in their host cell," says Raoult. But because amoebae feed on relatively large particles, over 500nm, they are one of the few organisms that can take in and host a giant virus. And since amoebae are not picky eaters, they typically contain a mixture of organisms. The giant virus adopts genes from the other organisms, including eukaryotes, bacteria and other viruses, that improve function. In the case of the Marseillevirus, genes with defense or repair functions are thought to have come from bacteria; those with metabolic functions likely have eukaryotic and bacteria origins; and those for signal transduction probably stem from eukaryotes, the scientists report. The team's findings led them to conclude that amoebae are "melting pots" for viruses, said Raoult, enabling viruses to create complex gene repertoires with varied genetic origins. It is unclear whether this new giant virus is pathogenic, but may turn out to be so, said Raoult, because of the virus's "repertoire of genes and the capability to resist intracellular killing."
**__Related stories:__***linkurl:A virus's virus;http://www.the-scientist.com/blog/display/54915/
[6th August 2008]
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Comments

December 9, 2009

I find this to be very interesting and timely. I am about to begin discussion on molecular genetics in my Biology class and this will be a great topic to add to the material. I find the ability for organisms to incorporate genetic information into that which already exists in their genome a cool adaptation and my students realize from this that evolution is very much alive and that the "little critters" are the ones we need to be concerned with. Cool stuff.\n\nD. Bogdanske\nBiology Department, Ripon HS
Avatar of: Dov Henis

Dov Henis

Posts: 97

December 14, 2009

Giant virus discovered \nhttp://www.the-scientist.com/blog/display/56208/\n\nDon,\n\nI find your comment interesting. About to begin discussion on molecular genetics in a biology class, you find the ability of "organisms" to incorporate "genetic information" into that which already exists in their genome... a "cool adaptation" and your students will realize from this that "evolution" is very much alive and that the "little critters" are the ones we need to be concerned with... \n\nWith sincere respect, I am trying to learn what is factually taught in a class on this subject: \n\n- who is/are the "organisms" you refer to? \n- what is this thing you term "genetic information", and in whose genome?\n- how is this "genetic information thing" incorporated into the genome?\n- what and whose is the "cool adaptation" in this case, and what is "adaptation"?\n- what is and how do you define "evolution"?\n- what is the significance of "evolution is very much alive"?\n- who are the "little critters" you refer to?\n\nA clearly obvious relationship should be expected between the clarity of the concepts taught in biology classes and the general state of comprehension, research and publications in the fields of life sciences...and the general state of comprehension and attitudes in all matters touched by life sciences...\n\nSincerely and respectfully,\n\nDov Henis

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Mettler Toledo
BD Biosciences
BD Biosciences