All known members of the genus are radioresistant: D. proteolyticus, D. radiopugnans, D. radiophilus, D. grandis, D. indicus, D. frigens, D. saxicola, D. marmoris, D. deserti,[5] D. geothermalis, and D. murrayi; the latter two are also thermophilic.
These findings support the notion of panspermia, the hypothesis that life exists throughout the Universe, distributed in various ways, including space dust, meteoroids, asteroids, comets, planetoids, or contaminated spacecraft.
It is often found in habitats rich in organic materials, such as sewage, meat, feces, or, soil, but has also been isolated from medical instruments, room dust, textiles, and dried foods.
[14][15][16] A dose of 5,000 Gy is estimated to introduce several hundred double-strand breaks (DSBs) into the organism's DNA (~0.005 DSB/Gy/Mbp (haploid genome)).
[17] A team of Croatian and French researchers led by Miroslav Radman have bombarded D. radiodurans to study the mechanism of DNA repair.
[21] In 2016, Massimiliano Peana et al. reported a spectroscopic study through NMR, EPR, and ESI-MS techniques on the Mn(II) interaction with two peptides, DP1 (DEHGTAVMLK) and DP2 (THMVLAKGED), whose amino acid composition was selected to include the majority of the most prevalent amino acids present in a Deinococcus radiodurans bacterium cell-free extract that contains components capable of conferring extreme resistance to ionizing radiation.
[22] In 2018, M. Peana and C. Chasapis reported by a combined approach of bioinformatic strategies based on structural data and annotation, the Mn(II)-binding proteins encoded by the genome of DR and proposed a model for Manganese interaction with DR proteome network involved in ROS response and defense.
[24] However, apart from its resistance to radiation, Deinococcus is genetically and biochemically very similar to other terrestrial life forms, arguing against an extraterrestrial origin not common to them.
In 2009, nitric oxide was reported to play an important role in the bacteria's recovery from radiation exposure: the gas is required for division and proliferation after DNA damage has been repaired.
[citation needed] Valerie Mattimore of Louisiana State University has suggested the radioresistance of D. radiodurans is simply a side effect of a mechanism for dealing with prolonged cellular desiccation (dryness).
In fact, this S-layer acts as a shield against electromagnetic stress, as in the case of ionizing radiation exposure, but also stabilizes the cell wall against possible consequent high temperatures and desiccation.
Not only has D. radiodurans been genetically modified for bioremediation applications, but also it has been discovered that it could perform a major role in biomedical research and in nanotechnology.
Bioremediation refers to any process that uses microorganisms, fungi, plants, or the enzymes derived from them, to return an environment altered by contaminants to its natural condition.
The mercuric reductase gene has been cloned from Escherichia coli into Deinococcus to detoxify the ionic mercury residue frequently found in radioactive waste generated from nuclear weapons manufacture.
To this extent, D. radiodurans mechanisms of protection against oxidative damage and of DNA reparation could be the starting points in research aimed to develop medical procedures to prevent aging and cancer.
Whereas chemical and physical methods to produce these nanoparticles are expensive and generate a huge amount of pollutants, biosynthetic processes represent an ecofriendly and cheaper alternative.
The importance of these nanoparticles relies on their medical applications as they have been demonstrated to exhibit activity against pathogenic bacteria, antifouling effects, and cytotoxicity to tumoral cells.
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 100 bacterial generations later.
[40] Horne et al. (2022) have studied the effects of desiccation and freezing on the microbial survivability to ionizing radiations considering the feasibility studies to return Martian subsurface soil samples for microbial characterization and for determining the most favorable landing sites of a future robotic exploration mission.
Nevertheless, Horne et al. (2022) consider the hypothesis that meteorite impacts could have dispersed Martian soil and heated locally the subsurface during the geological history of Mars, heating sporadically from time to time the local environment, melting the frozen ice and giving perhaps a chance to a hypothetical distant Martian extremophile resembling its terrestrial cousin Deinococcus radiodurans to grow again for short moment before to rapidly become again frozen and dormant for millions of years.
So, for returning subsurface soil samples from Mars for microbial characterization with a potentially "successful" mission like the European Rosalind Franklin rover, it would be necessary to target a relatively young impact crater to increase the chances of discovering dormant extremophile micro-organisms surviving in the dry and frozen Martian subsurface environment relatively protected from the lethal ionizing radiations.