Scientists have found a new clue to the remarkable capability of an unusual bacterial species, Deinococcus radiodurans, to survive large doses of radiation and extended periods without water.
This bacterium can withstand a dose of radiation thousands of times more intense than what would prove lethal to a person. Although the radiation scrambles the microbe's DNA, D. radiodurans has an unmatched talent for repairing the genetic damage. This skill apparently evolved as a way to protect the bacterium from DNA mutations produced during long-term dehydration (SN: 12/12/98, p. 376: http://www.sciencenews.org/pages/sn_arc98/12_12_98/bob1.htm).
Microbiologists have struggled to understand how D. radiodurans so easily stitches its DNA back together. One factor may be molecules called single-stranded DNA-binding (SSB) proteins, which have been implicated in the copying and repairing of genes. "In all organisms, [these] proteins are critical for genome