Deinococcus radiodurans
Deinococcus radiodurans is a gram-positive, nonmotile, red-pigmented bacterium. It was originally identified as a contaminant of irradiated canned meat in 1956.
Deinococcus radiodurans has the systems for DNA repair, DNA damage export and genetic redundancy. It can recover from desiccation (loss of water) and starvation. It has a very high tolerance to radiation forms like gamma radiation. It is so far known as the most radioactive resistant organism. Thioredoxin reductase is an enzyme found in the cells' response to double-strand DNA breaks.
D. radiodurans has a gene sequence that encodes for a protein that is very similar to the RecD enzyme found in E. coli. This significant finding suggests that this RecD-like protein in D. radiodurans is an important part of the repair system it uses.
It may be possible to make other bacteria as radiation resistant as D. radiodurans by changing their genetics. One research team in China is trying to insert an expressive recombinant Mn-SOD protein from D. radiodurans into E.coli BL21. The real challenge here is making the protein self-sustaining in the new species. The team has "provided the foundations for further studies and applications of the recombinant Mn-SOD".
Genus
The genus Deinococcus has 47 species, which share these characteristics. D. radiodurans is the one discovered first, and on which most experiments have been done. All members of the genus are radio-resistant.
References
Gram-positive bacteria
Extremophiles