D. radiodurans-World's Toughest Bacteria
Deinococcus radiodurans was discovered by Arthur Anderson at the Oregon Agricultural Experiment Station in Corvallis, Oregon. It was isolated when an experiment was being done to test whether canned food could be sterilized using a high amount of gamma radiation or not. The result was that almost all forms of life were killed except D. radiodurans. This is when it was first isolated.
It is a polyextremophile as it can survive extreme radiation, cold, dehydration, acid, and vacuum also. It has also been listed in the Guinness Book Of World Records as 'The toughest bacteria of the World'. In the year 2020, it was found that this bacteria survived in outer space for up to three years based on studies held by the International Space Station(ISS). Hence, this also supported the theory of Panspermia which says that life exists in the entire universe and was transported by comets, meteors, and other celestial objects. Russian and American scientists suggested that the radioresistance of this bacteria had origin from the surface of Mars and had been evolved and transported to Earth by a meteor.
It is a large circular bacteria of about 1.5 to 3.5 μm diameter and is seen as a tetrad that is four cells sticking to each other. It is a gram-positive bacteria although it has a cell envelope that resembles that of gram-negative cells. D. radiodurans is capable of withstanding an acute dose of 5,000 grays (Gy), or 500,000 rad, of ionizing radiation whereas 5 Gy can kill a human, and more than 4,000 Gy will kill the radiation-resistant tardigrade which has survived all the world's mass extinction. This bacteria uses manganese as antioxidants to protect itself from radiation
It is used for the treatment of nuclear waste, bioremediation, synthesis of gold and silver, and also in the study of aging and cancer models. Deinococcus radiodurans has a unique quality in which it can repair both single- and double-stranded DNA. In the year 2003, it was demonstrated that this bacteria could be used as a means of data storage. They translated the song "It's a Small World" into a series of DNA segments 150 base pairs long, inserted these into the bacteria, and were able to retrieve them without errors up to 100 bacterial generations. Further studies and applications about D. radiodurans are still in process.