Deinococcus radiodurans

Pages: 2 (273 mots) Publié le: 13 décembre 2010
Deinococcus radiodurans

D. radiodurans was discovered in 1956 by Arthur W. Anderson at the Oregon Agricultural Experiment Station in Corvallis. Experiments werebeing performed to determine if canned food like tin of meat could be sterilized using high doses of gamma radiation but the decomposition process doesn’t stop, and the bacteriawas isolated.
This bacteria was a deinococcus radiodurans and nicknamed “Conan the bacterium” referred to “Conan the barbarian” because of his hardiness.
Gram-positive,red-pigmented. Four cells normally stick together ( Chomosom I 2,648,638 bp and II 412,348 bp , a plasmid CP 45,704 bp and a megaplasmid MP1 177,466 bp >100kpb).
Maybe origin frommars.
It is often found in habitats rich in organic materials, such as soil, meat, or sewage, but has also been isolated from dried foods, or medicalinstruments.
It’s one of the most radioresistant organisms known.
It’s a polyextremophile bacteria because it resists to ionizing radiation, ultraviolet light, desiccation,hydrogen peroxide, vacuum, acid, and extremes of temperature.
DNA process
D.Radiodurans can survive because of a DNA repair process. It isolates the damaged segments in a controlledarea and repairs it. This bacteria can also repair many small fragments from an entire chromosome.
It usually repairs breaks in its chromosomes within 12–24 hours through a2-step process .
First, D. radiodurans reconnects some chromosome fragments through a process called single-strand annealing. In the second step, a protein mends double-strandbreaks through homologous recombination.
One of the main application is the bioremediation to consume and digest solvents and heavy metals, even in a highly radioactive site
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