Deinococcus radiodurans Kirsten J. Reynolds
Some bacteria grow rather well in what could be described as battery acid, while others grow in a lake so salty that it is called the Dead Sea. Another group loves to grow in water so hot it would boil if not for the pressure on it. These same organisms consider room temperature to be as cold as the polar ice cap. The literal meaning of Deinococcus radiodurans means "strange berry that withstands radiation." This meaning gives us just a glimpse as to what this microorganism can do.
Arthur W. Anderson at Oregon Agricultural Experiment Station in Corvallis discovered this microbe in 1956. Deinococcus radiodurans was isolated from a can of ground meat that had spoiled despite having been sterilized with radiation. Deinococcus radiodurans is a gram-positive, non-sporeforming, aerobe that requires a very complex media to produce pink to reddish colonies. Some of the characteristics of this "world’s toughest bacterium" include an extreme resistance to genotoxic chemicals, oxidative damage, dehydration, and high levels of ionizing and ultraviolet radiation. Deinococcus radiodurans can withstand radiation levels 1000 times higher than would completely debilitate any human on earth. These amazing characteristics can be contributed to one main characteristic of Deinococcus radiodurans; its ability to repair damaged chromosomes.
One of the two main topics of research surrounding this microbe is its remarkable ability to repair major damage to its own DNA. The DNA repair consists of a two step process of with single-strand annealing and a rapid homologous recombination. The speed at which homologous recombination occurs has given rise to the "Life Saver" hypothesis stating that in order to speed homologous recombination Deinococcus radiodurans aligns copies of it s genome so that identical DNA sequences are near each other.
The other main topic of research is the fact that Deinococcus radiodurans has evolved to be so radiation resistant when radiation of such a magnitude has only existed on earth during the last 50 years. It is believed that Deinococcus radiodurans has evolved to survive long periods of dehydration, and that the resistance to radiation is only incidental to the discovery and development of radiation emitting technology during the second half of this century.
The discovery of this microbe has led to more detailed research on how this microbe lives and how it can help the earth. The bacterium is used to clean up radiation s at sites once used for testing nuclear weapons. Deinococcus radiodurans might be used on the mission to Mars in hope that its characteristics can make the soil less corrosive to spacesuits and equipment. This microbe has many qualities that we are just now becoming aware of. I look forward to hearing about further discoveries in the future whether it is from mars or earth.
*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.
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