Thursday, February 28, 2013

This virus can steal it's host's immune system

Source: Nature via io9

Tufts University researchers recently uncovered an adaptation they could only describe as "remarkable": a virus that captures its host's immune system, which it then uses for an ensuing attack.

A virus, in this case a bacteriophage (or just "phage"), can acquire a fully functional and adaptive immune system.

Armed with its host's immune system, the phage can kill the cholera bacteria and multiply to produce more phage offspring — which then go on to kill more cholera bacteria. It does this by targeting and destroying specific inhibitory genes of the host cell by cutting the target genes into pieces. It's by disarming these genes that the phage can also disarm the host cells, allowing it to infect and kill them.

It's worth noting, however, that the phage is not actually producing its own immune system; it doesn't have the genetics for it. Instead, it has to capture one, effectively parasitizing another organism's genome.

The discovery is also interesting in that it could lead to phage therapy — the use of phages to treat bacterial diseases. Given the rise of so-called superbugs and the ever-decreasing effectiveness of antibiotics, an advanced genetically designed phage therapy could prove to be the intervention we're all waiting for.

Size Estimates of the Object That Disintegrated Over Chelyabinsk, Russia

Source: NASA

New information provided by a worldwide network of sensors has allowed scientists to refine their estimates for the size of the object that entered that atmosphere and disintegrated in the skies over Chelyabinsk, Russia, at 7:20:26 p.m. PST, or 10:20:26 p.m. EST on Feb. 14 (3:20:26 UTC on Feb. 15).

The estimated size of the object, prior to entering Earth's atmosphere, has been revised upward from 49 feet (15 meters) to 55 feet (17 meters), and its estimated mass has increased from 7,000 to 10,000 tons. Also, the estimate for energy released during the event has increased by 30 kilotons to nearly 500 kilotons of energy released. These new estimates were generated using new data that had been collected by five additional infrasound stations located around the world – the first recording of the event being in Alaska, over 6,500 kilometers away from Chelyabinsk. The infrasound data indicates that the event, from atmospheric entry to the meteor's airborne disintegration took 32.5 seconds. The calculations using the infrasound data were performed by Peter Brown at the University of Western Ontario, Canada.

"We would expect an event of this magnitude to occur once every 100 years on average," said Paul Chodas of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "When you have a fireball of this size we would expect a large number of meteorites to reach the surface and in this case there were probably some large ones."

The trajectory of the Russia meteor was significantly different than the trajectory of the asteroid 2012 DA14, which hours later made its flyby of Earth, making it a completely unrelated object. The Russia meteor is the largest reported since 1908, when a meteor hit Tunguska, Siberia.