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Virophage' suggests viruses are alive : MAMA virus

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  • Virophage' suggests viruses are alive : MAMA virus

    just for fun : MAMA virus , and his satellite : sputnik virus

    http://www.nature.com/news/2008/0808...l/454677a.html







    Virophage' suggests viruses are alive

    Evidence of illness enhances case for life.
    Helen Pearson
    <!-- --> Giant mamavirus particles (red) and satellite viruses of mamavirus called Sputnik (green).REF. 1


    The discovery of a giant virus that falls ill through infection by another virus<sup>1</sup> is fuelling the debate about whether viruses are alive.
    “There’s no doubt this is a living organism,” says Jean-Michel Claverie, a virologist at the the CNRS UPR laboratories in Marseilles, part of France’s basic-research agency. “The fact that it can get sick makes it more alive.”
    Giant viruses have been captivating virologists since 2003, when a team led by Claverie and Didier Raoult at CNRS UMR, also in Marseilles, reported the discovery of the first monster<sup>2</sup>. The virus had been isolated more than a decade earlier in amoebae from a cooling tower in Bradford, UK, but was initially mistaken for a bacterium because of its size, and was relegated to the freezer.
    Closer inspection showed the microbe to be a huge virus with, as later work revealed, a genome harbouring more than 900 protein-coding genes<sup>3</sup> — at least three times more than that of the biggest previously known viruses and bigger than that of some bacteria. It was named Acanthamoeba polyphaga mimivirus (for mimicking microbe), and is thought to be part of a much larger family. “It was the cause of great excitement in virology,” says Eugene Koonin at the National Center for Biotechnology Information in Bethesda, Maryland. “It crossed the imaginary boundary between viruses and cellular organisms.”
    “There's no doubt that this is a living organism. The fact that it can get sick makes it more alive.”
    <cite id="n1"></cite>

    Now Raoult, Koonin and their colleagues report the isolation of a new strain of giant virus from a cooling tower in Paris, which they have named mamavirus because it seemed slightly larger than mimivirus. Their electron microscopy studies also revealed a second, small virus closely associated with mamavirus that has earned the name Sputnik, after the first man-made satellite.
    With just 21 genes, Sputnik is tiny compared with its mama — but insidious. When the giant mamavirus infects an amoeba, it uses its large array of genes to build a ‘viral factory’, a hub where new viral particles are made. Sputnik infects this viral factory and seems to hijack its machinery in order to replicate. The team found that cells co-infected with Sputnik produce fewer and often deformed mamavirus particles, making the virus less infective. This suggests that Sputnik is effectively a viral parasite that sickens its host — seemingly the first such example.
    The team suggests that Sputnik is a ‘virophage’, much like the bacteriophage viruses that infect and sicken bacteria. “It infects this factory like a phage infects a bacterium,” Koonin says. “It’s doing what every parasite can — exploiting its host for its own replication.”
    Sputnik’s genome reveals further insight into its biology. Although 13 of its genes show little similarity to any other known genes, three are closely related to mimivirus and mamavirus genes, perhaps cannibalized by the tiny virus as it packaged up particles sometime in its history. This suggests that the satellite virus could perform horizontal gene transfer between viruses — paralleling the way that bacteriophages ferry genes between bacteria.
    Virophages may be common in plankton blooms.J. SCHMALTZ/NASA


    The findings may have global implications, according to some virologists. A metagenomic study of ocean water<sup>4</sup> has revealed an abundance of genetic sequences closely related to giant viruses, leading to a suspicion that they are a common parasite of plankton. These viruses had been missed for many years, Claverie says, because the filters used to remove bacteria screened out giant viruses as well. Raoult’s team also found genes related to Sputnik’s in an ocean-sampling data set, so this could be the first of a new, common family of viruses. “It suggests there are other representatives of this viral family out there in the environment,” Koonin says.
    By regulating the growth and death of plankton, giant viruses — and satellite viruses such as Sputnik — could be having major effects on ocean nutrient cycles and climate. “These viruses could be major players in global systems,” says Curtis Suttle, an expert in marine viruses at the University of British Columbia in Vancouver.
    “I think ultimately we will find a huge number of novel viruses in the ocean and other places,” Suttle says — 70% of viral genes identified in ocean surveys have never been seen before. “It emphasizes how little is known about these organisms — and I use that term deliberately.”
    • References
      1. <!-- . -->La Scola, B. et al. Nature doi:10.1038/nature07218 (2008).
      2. <!-- . -->La Scola, B. et al. Science 299, 2033 (2003). | Article | PubMed | ChemPort |
      3. <!-- . -->Raoult, D. et al. Science 306, 1344–1350 (2004).
      4. <!-- . -->Monier, A., Claverie, J.-M. & Ogata, H. Genome Biol. 9, R106 (2008). | Article | PubMed |

  • #2
    Re: Virophage' suggests viruses are alive : MAMA virus

    I always felt that viruses are living.


    UV or heat can "kill" the virus

    Flumist contains "life" attenuated viruses

    viruses reproduce, evolve genetically, have phylogenic trees
    I'm interested in expert panflu damage estimates
    my current links: [url]http://bit.ly/hFI7H[/url] ILI-charts: [url]http://bit.ly/CcRgT[/url]

    Comment


    • #3
      Re: Virophage' suggests viruses are alive : MAMA virus

      Hello gsgs
      we can say that some viruses are more "alive" than others (it brings to wonder where Life begins or what is life .)

      what I want to highlight too, is that it took time to understand that Mimi virus was a virus ..
      At first, researchers thought they had to deal with a strange bacterium, because Mimi is a very big virus which contains proteins and which infects amoeba.

      One day, by looking at ME, they saw that Mimi had an virus envelope.

      Another example: a very large sea bacteria was discovered in 2000, I think ( one millimeter)
      It has not been found before, because it was visible with eyes, on the surface of sea..and everybody knows that a microscope is needed to see a bacterium..

      what we see and find,depends on our prejudices.

      Comment


      • #4
        Re: Virophage' suggests viruses are alive : MAMA virus

        "Another example: a very large sea bacteria was discovered in 2000, I think ( one millimeter)
        It has not been found before, because it was visible with eyes, on the surface of sea.."


        Another decade of heavy Earth pollution with climate changing effects, and the bacteria/viruses/chimeras/... would became visible with eyes as elefants ...


        After a half century of microbial experiments we are now prone for everything.

        Comment


        • #5
          Re: Virophage' suggests viruses are alive : MAMA virus

          Originally posted by Anne View Post
          Hello gsgs
          we can say that some viruses are more "alive" than others (it brings to wonder where Life begins or what is life .)

          what I want to highlight too, is that it took time to understand that Mimi virus was a virus ..
          At first, researchers thought they had to deal with a strange bacterium, because Mimi is a very big virus which contains proteins and which infects amoeba.

          One day, by looking at ME, they saw that Mimi had an virus envelope.

          Another example: a very large sea bacteria was discovered in 2000, I think ( one millimeter)
          It has not been found before, because it was visible with eyes, on the surface of sea..and everybody knows that a microscope is needed to see a bacterium..

          what we see and find,depends on our prejudices.
          An open mind in the field of sciences of life is clearly needed to people works in the media.

          Since more organism are already known to be a sort of intermediate stage between a whole-cell-enveloped organism (eucharyotes), for examples the mycoplasmas and rickettsias (prochariotes). Between prochariotes and acellulates (virus) there is enough space for new discoveries.

          It will be interesting to know if the newest organism may be susceptible to certain antibiotics and if may also interact in some way to produce new compounds...

          Comment


          • #6
            Re: Virophage' suggests viruses are alive : MAMA virus

            you express better than me, what I think... (grrr .. ) !
            open mind , open eyes, and no prejudices..

            Comment


            • #7
              Re: Virophage' suggests viruses are alive : MAMA virus

              Originally posted by Anne View Post
              you express better than me, what I think... (grrr .. ) !
              open mind , open eyes, and no prejudices..
              Hi Anne,

              I didn't know if the (grrr ..) was for me or not, so I repeat:

              "After a half century of microbial experiments we are now prone for everything. " - to appear

              Don't take the elephants joke as a prejudice.

              After a whole bunch of organisms naturaly created and living at deep ocean volcano sites on diferent presumptions than we above, all is possible naturaly.

              But, all is possible unnaturaly also.

              Comment


              • #8
                Re: Virophage' suggests viruses are alive : MAMA virus

                Burton:I'm going to try a 2 micron filter.
                Male Technician: This one's big, I'll have to get me a fly swatter.
                I'm interested in expert panflu damage estimates
                my current links: [url]http://bit.ly/hFI7H[/url] ILI-charts: [url]http://bit.ly/CcRgT[/url]

                Comment


                • #9
                  Re: Virophage' suggests viruses are alive : MAMA virus

                  Originally posted by gsgs View Post
                  Burton:I'm going to try a 2 micron filter.
                  Male Technician: This one's big, I'll have to get me a fly swatter.
                  , what would Livingstone said about the swatter ...

                  gs., you forgot the "Big Grin" after your sentence.

                  Comment


                  • #10
                    Re: Virophage' suggests viruses are alive : MAMA virus

                    sorry, Tropical, I answered to Ironrehopper

                    your joke is not prejudice.

                    Comment


                    • #11
                      Re: Virophage' suggests viruses are alive : MAMA virus

                      http://www.pnas.org/content/early/20...15107.abstract

                      a major marine microflagellate grazer is infected by a giant virus, Cafeteria roenbergensis virus (CroV),
                      genome of 730 kb
                      38-kb bacterial origin,carbohydrate metabolizing enzymes

                      http://de.wikipedia.org/wiki/Cafeteria_roenbergensis


                      Every day, marine viruses kill about 20 percent of the ocean's microorganisms,
                      which produce about half the oxygen on the planet.


                      Read more: Giant marine virus found - The Scientist - Magazine of the Life Sciences
                      http://www.the-scientist.com/news/di...#ixzz13RsUabXu
                      I'm interested in expert panflu damage estimates
                      my current links: [url]http://bit.ly/hFI7H[/url] ILI-charts: [url]http://bit.ly/CcRgT[/url]

                      Comment


                      • #12
                        Re: Virophage' suggests viruses are alive : MAMA virus

                        Wonderfull !
                        thank you gsgs..

                        CroV replicates inside the single-celled zooplankter Cafeteria roenbergensis, ( the name of virus and microorganism are the same .. with a v for " virus" )


                        Like amoebae, C. roenbergensis harbor many microorganisms simultaneously, making them "a good place to exchange genes," Raoult said. "When you live in a phagocytic protist, such as this one, you meet a number of microorganisms, and then you can exchange genes and get a bigger genome."

                        Indeed, of the 500 protein-coding genes Suttle and his colleagues found when they sequenced the virus's genome, about half were similar to those in eukaryotes, bacteria, archaea, and other giant viruses. Those with known function included genes that code for translation factors, DNA repair enzymes, ubiquitin pathway components, and tRNAs.

                        Read more: Giant marine virus found - The Scientist - Magazine of the Life Sciences http://www.the-scientist.com/news/di...#ixzz13T6ebenY






                        Marine viruses play a critical role in the ecosystem of the world’s oceans but have been largely ignored because most of them do not have a direct economic impact on fisheries or other important industries. Nevertheless, marine viruses are significant mortality agents of marine microorganisms and control their abundance and diversity. Cafeteria roenbergensis virus (CroV) is the first well-studied virus infecting a marine phagotrophic flagellate. CroV replicates inside the single-celled zooplankter Cafeteria roenbergensis, which is widespread throughout the world’s oceans.Its genome size is about 730 kbp, making it the second largest viral genome known. Sequence analysis shows that CroV is related to Mimivirus, the world’s largest virus. Initial cryo-EM images of CroV show that CroV has an approximate size of 3,000Å from one vertex to the other. Unlike Mimivirus (approximately 5,000Å in diameter without fiber), CroV does not contain long fibers on its surface but does share a similar hexagonal profile and a multiple layer internal structure.

                        http://acs.confex.com/acs/swrm09/web...aper78399.html

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