Radiation Resistant Rotifers
Summary (Mar 28, 2008): An animal common to marine environments on Earth has shown extreme resistance to radiation. Radiation is one of the greatest dangers for life traveling in space, and the finding could yield clues about how life might survive beyond Earth.
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Radiation Resistant Rotifers
Based on an
Harvard University news release
Common Aquatic Animals Show Extreme Resistance to Radiation | The bdelloid rotifer Philodina roseola (ca 400 microns).
Credit: Harvard, Department of Molecular and Cellular Biology |
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Scientists at Harvard University have found that a common class of freshwater invertebrate animals called bdelloid rotifers are extraordinarily
resistant to ionizing radiation, surviving and continuing to reproduce after doses of gamma
radiation much greater than that tolerated by any other animal species studied to date. Radiation is one of the greatest
dangers faced by life traveling in space, and the new findings could help scientists understand how organisms might adapt to survive
beyond our planet.
Because free radicals such as those generated by radiation have been implicated in inflammation, cancer, and aging in higher organisms, the findings -- published in the Proceedings of the National Academy of Sciences by Harvard's Matthew Meselson and graduate student Eugene Gladyshev -- could stimulate new lines of research into these medically important problems.
| When in space, the cells of living organisms are battered by space radiation that can damage DNA.
Credit: NASA |
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"Bdelloid rotifers are far more resistant to
ionizing radiation than any of the hundreds of other animal species for which radiation resistance has been examined," says Meselson, Thomas Dudley Cabot Professor of the Natural Sciences in Harvard's Faculty of Arts and Sciences. "They are able to recover and resume normal reproduction after receiving a dose of radiation that shatters their genomes, causing hundreds of DNA double-strand breaks which they are nevertheless able to
repair."
Meselson and Gladyshev found that the bdelloid rotifers Adineta vaga and Philodina roseola remained reproductively viable after doses of radiation roughly five times greater than other classes of rotifers and other animals could endure.
| When traveling in space, astronauts can be exposed to harmful doses of radiation originating from sources like the Sun and galactic cosmic rays.
Credit: NASA/ESA/SOHO |
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Such radiation
resistance appears not to be the result of any special protection of DNA itself against breakage, the researchers say, but instead reflects bdelloid rotifers' extraordinary ability to protect their DNA-repairing machinery from radiation damage.
Roughly a half-millimeter in size and commonly observed under microscopes in high-school biology classes, bdelloid rotifers are highly unusual in several regards: They appear to be exclusively asexual, have relatively few transposable genes, and can survive and reproduce after complete desiccation at any stage of their life cycle. Meselson and Gladyshev hypothesize that it's this last property that explains bdelloids' apparently unique resistance to radiation.
Bdelloid rotifers have been widely studied since at least 1702, when the renowned Dutch scientist and microscopy pioneer van Leeuwenhoek added water to dust retrieved from a rain gutter on his house and observed the organisms in the resulting fluid. He subsequently described the creatures in a letter to Britain's Royal Society, which still counts an envelope of van Leeuwenhoek's rain-gutter dust among its holdings.
Meselson and Gladyshev's work is supported by the National Science Foundation's Eukaryotic Genetics Program.
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Friday, March 28, 2008
