Ionizing Radiation Resistance
D. radiodurans is capable of withstanding an acute dose of 5,000 Gy (500,000 rad) of ionizing radiation with almost no loss of viability, and an acute dose of 15,000 Gy with 37% viability. A dose of 5,000 Gy is estimated to introduce several hundred double-strand breaks (DSBs) into the organism's DNA (~0.005 DSB/Gy/Mbp (haploid genome)). For comparison, a chest X-ray or Apollo mission involves about 1 mGy, 5 Gy can kill a human, 200-800 Gy will kill E. coli, and over 4,000 Gy will kill the radiation-resistant tardigrade.
Several bacteria of comparable radioresistance are now known, including some species of the genus Chroococcidiopsis (phylum cyanobacteria) and some species of Rubrobacter (phylum actinobacteria); among the archaea, the species Thermococcus gammatolerans shows comparable radioresistance. Deinococcus radiodurans also has a unique ability to repair damaged DNA. It isolates the damaged segments in a controlled area and repairs it. This bacteria can also repair many small fragments from an entire chromosome.
Read more about this topic: Deinococcus Radiodurans
Famous quotes containing the words radiation and/or resistance:
“There are no accidents, only nature throwing her weight around. Even the bomb merely releases energy that nature has put there. Nuclear war would be just a spark in the grandeur of space. Nor can radiation “alter” nature: she will absorb it all. After the bomb, nature will pick up the cards we have spilled, shuffle them, and begin her game again.”
—Camille Paglia (b. 1947)
“The aim of every political association is the preservation of the natural and imprescriptible rights of man. These rights are liberty, property, security and resistance to oppression.”
—French National Assembly. Declaration of the Rights of Man (drafted and discussed August 1789, published September 1791)