Over at her old blog, Karmen had a nice overview of Deinococcus radiodurans, a fascinating organism that’s able to withstand many different extremes: genotoxic chemicals, oxidative damage, high levels of ionizing and ultraviolet radiation, dehydration, and, as the name suggests, incredibly high doses of radiation. (We’re talking high–up to 5,000 Gy without breaking a sweat, while it only takes about 10 Gy to kill a human). However, despite 50 years of study, no one’s really figured out just how it does it, though some clues (such as higher levels of manganese and low levels of iron) have emerged that make D. radiodurans stand out). Over at Small Things Considered, a recent paper is highlighted suggesting that these minerals protect not the DNA from damage, but instead, the proteins:
The researchers postulated that manganese ions transform damaging superoxide radicals (which can’t easily cross the cell membrane) into hydrogen peroxide, which can be excreted. Indeed, resistant cells excrete peroxide following radiation exposure.