Tuesday, September 10, 2013

A Virus that gets infected by a virus.

In 1992, a microbiologist named Timothy Rowbotham, was searching for the cause of a pneumonia outbreak in Bradford, England. During his hunt, he took some water from a hospital’s cooling tower and put it under a microscope. In this water he found a promising candidate; a sphere of bacterial size, sitting inside an amoeba. Rowbotham believed he had found a new bacterium and called it Bradfordcoccus. He then spent years trying to figure out if it was the cause of the pneumonia outbreak. Budget cuts then forced Rowbotham to abandon his study and close his lab in 1998. He handed over his samples to his French colleagues for storage. For five years ‘Bradfordcoccus’ languished in obscurity, until Bernard La Scola of Mediterranean University, decided to take another look at it. La Scola, found that Bradfordcoccus did not have the smooth surface of spherical bacteria. Instead it was made of made of interlocking plates and hair like protein threads were radiating from its outer shell. The only thing in nature with such shells and threads were viruses. Until then no one had known any virus which was as big as Bradfordcoccus, it was hundred times too big to be a virus. La Scola discovered that it reproduced by invading amoeba and forcing it to build copies of itself. Only viruses behave this way. La Scola, gave Bradfordcoccus a new name to reflect its viral nature- Mimivirus (in honour of its ability to mimic bacteria).Genetic study of Mimivirus, provided more surprises. It had 1,262 genes. It was as if someone took the genomes of flu, the cold, smallpox and hundred of other viruses and stuffed them all into one protein shell. It had more genes than some species of bacteria. Mimivirus, was breaking all the rules of the virus world. Scientist found Mimivirus, in the lungs of patients suffering from pneumonia, but they are unsure if it causes pneumonia or colonise in people who are already sick. Scientist also do not know what mimivirus do with all their genes. In 2008, La Scola discovered that Mimivirus can be infected by a virus of its own. This is the first time anyone has found a virus of a virus. We humans are a blend of mammal and virus. Remove our virus derived genes and we would be unable to reproduce. A mimivirus, in an amoeba, functions just like how a human cell would function, probably giving us a peek into how first life evolved on earth.

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