You never know exactly what you'll find when you go churning up muck, but apparently odds are pretty good you'll find some viruses. The other day we heard how raw sewage is a hotbed of unknown viruses; now a French team has found the largest virus ever, living in the sea off the coast of Chile.
Named Megavirus chilensis, it barely beats the previous record-holder, Mimivirus, as the world's most giant virus. It's a linear double-stranded DNA molecule with 1,259,197 base pairs — by far the biggest viral genome ever discovered. Its complex genome gives it some abilities, like protein translation, that overlap with simple cellular organisms like parasitic bacteria, according to the researchers who found it. Viruses aren't cellular organisms; they need to invade other cells and hijack their machinery to produce new versions of themselves.
It is so large that it can be seen with a regular light microscope rather than an electron microscope, as Jean-Michel Claverie of Aix-Marseille University in Marseille, France, told the BBC.
It has several DNA-repair enzymes, which allow it to correct damage due to ultraviolet light, radiation or chemicals, Claverie and colleagues say. Its cell-like genes may be a holdover from an ancestor it shares with Mimivirus, which may have gotten its genes from a cell.
Like Mimivirus, Megavirus infects amoebas, single-celled organisms that live in water. Also like Mimivirus, Megavirus employs a Stargate structure (really its name) to invade a host cell. The opening of this five-pronged structure triggers the release of the virus' genetic material.
Megavirus turned up in an exploration trawl off the coast of Las Cruces in central Chile. Mimivirus was isolated from a water cooling tower in the UK in 1992, BBC says.
Anyone with an interest in its phylogeny can check out the genome browser, available here. The paper is published in the online edition of the Proceedings of the National Academy of Sciences.
The line between "life" and "not-life" is becoming more and more blurred. Things like giant viruses and prions (mad cow disease) make me wonder if there even is such a line.
They had me at "Stargate".
Prions are way smaller than a virus, and can be thought of as a misfolded protein that causes other proteins to fold the same when they come into contact with it!
When something is touted as the worlds largest, you usually get an actual value for the size. Thanks pop sci for proving that you don't need to actually give any real data to back up your claims.
The article did give a value for the size; 1,259,197 base pairs. Oh, you were thinking in terms of length. Not what they meant...
@Harry Caray...1st, bugger off, now that i got that out of the way, quit trolling! it is not popsci's claim, they are only reporting someone elses claim: if you want more info click on the link popsci provided; in other words, quit being lazy; sorry, havn't had my coffee yet, cheers