Monday, September 29, 2014

Radiotrophic Fungi Thrive on Gamma Radiation

In 1986 the Chernobyl Nuclear Power Plant suffered a catastrophic meltdown which irradiated thousands of square miles. The Chernobyl Exclusion Zone is the area around the reactor in a 30 kilometer (18 mile) radius also known as the Zone of Alienation, an area of mandatory resettlement. This disaster spread 200 times more radioactivity than the bombs that were dropped on Hiroshima and Nagasaki combined.
In 1991, five years after the meltdown, slimy, black molds were discovered on the walls inside the Chernobyl Nuclear Power Plant. Samples of the fungi were collected and studied at the Albert Einstein College of Medicine in New York City. They discovered that the mold was a collection of several fungi which contained melanin, a natural pigment found in most organisms. In order to test the effect of radiation on these bacteria the team exposed colonies of them to gamma rays 500 times as intense as the normal radiation background on Earth's surface. The colonies grew up to three times as fast as normal. In order to have a control group with which to compare the rate of growth, the created a mutant "albino" form of the fungus, which produced no melanin. This white fungus grew at a normal pace. Extrapolating their results, scientists discovered that the melanin in these fungi was used to convert gamma radiation into chemical energy to enhance the growth of these organisms. Co-researcher Ekaterina Dadachova  stated that, "Just as the pigment chlorophyll converts sunlight into chemical energy that allows green plants to live and grow, our research suggests that melanin can use a different portion of the electromagnetic spectrum - ionizing radiation - to benefit the fungi containing it”.
This was an enormous discovery, the radiation levels in the heart of the reactor were so great that scientists never expected to find any life inside of it, much less a group of organisms that were strengthened by it! Until now, melanin's biological role in fungi - if any - had been a mystery. This discovery has great potential and far-reaching implications. In space, ionizing ration is very prevalent, using this discovery, astronauts may be able to grow and rely on fungi like this as a self-replenishing food source for long missions bringing interplanetary travel that much closer.
 The melanin in these fungi is chemically identical to that contained in our own skin cells begging the question, does the melanin in our skin harvest energy from background radiation as well? This and many other questions are still being analyzed and may someday change the world we live in.

No comments:

Post a Comment