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Monday, October 15, 2012

Jumping DNA rides aboard a virus


Jumping DNA rides aboard a virus, which infects a giant virus, which infects an amoeba, which infected a woman’s eye

Earlier this year, a 17-year-old French woman arrived at her ophthalmologist with pain and redness in her left eye. She woman had been using tap water to dilute the cleaning solution for her contact lenses, and even though they were meant to be replaced every month, she would wear them for three. As a result, the fluid in her contact lens case had become contaminated with three species of bacteria, an amoeba called Acanthamoeba polyphaga that can caused inflamed eyes.
The mystery of the woman’s inflamed eyes was solved, but Bernard La Scola and Christelle Desnueslooked inside the amoeba, they found more surprises.
It was carrying two species of bacteria, and a giant virus that no one had seen before—they called it Lentille virus. Inside that, they found a virophage—an virus that infects other viruses—which they called Sputnik 2. And in both Lentille virus and Sputnik 2, they found even smaller genetic parasites – tiny chunks of DNA that can hop around the genomes of the virus, and stow away inside the virophage. They called these transpovirons.
So, the poor red eyes of the French patient were carrying an entire world of parasites, nested within one another like Russian Matryoshka nesting dolls. The transpovirons were hidden in the virophage, which infected the giant virus, which infected the amoeba, which infected the woman’s eyes.
Rise of the virophages
The same team found the first virophage – Sputnik – back in 2008, under similar circumstances. In dirty water from a Parisian cooling tower, they had i..