The bacteria Deinococcus radiodurans has the fastest DNA repairing system. This bacterium is a polyextremophile, capable of withstanding attacks from acid baths, high and low temperatures, lethal doses of radiation and even nuclear catastrophes. This bacterium is placed in the Guinness Book of World Records as the World’s Toughest Bacterium. This bacterium usually exists in tetrads and may be used in bioremediation processes as it is capable of degrading toluene released as waste in nuclear reactions. It can also be used to test for the existence of life in extreme conditions. No one really knows what the microbe’s natural habitat is, as it has been found in extremely diverse environments, from within elephant dung to granite found in the Antarctic dry valleys. And thus the natural habitat of the microbes is still under mystery.
The reason for such high toughness present in this organism is partially found to be due to the occurrence of 4 to 10 copies of additional genome. Because of the extra genome this organism is capable of recovering the genomes even after the radiation exposure or any other extreme conditions. This means that the additional genome present in this organism makes it to repair its gene that is affected due to some problems. Not only the extra genomes are responsible for fastest repair system and there may be some other factors which also contribute to this fastest repair of genes. This organism also contains some unusual minerals which may also be the reason for this. Elemental iron and manganese concentrations are present in this organism and this may also lead to enhancing the DNA repair system. Resistance is provided in these bacteria due to the presence of high cytosolic manganese and low iron concentration. Because of this protein oxidation is being prevented and this is done by ionizing the radiations. However this cannot prevent the DNA from damage.
Super oxides are transformed in to hydrogen peroxides with the help of manganese. Generally super oxides are called reactive oxygen species and these are harmful since it causes stress in the cells which are basically due to the oxidation and thus kills the cell. After the cell is exposed to ionizing radiations these are produced. The proteins that are responsible for the DNA repair has to be protected from being attacked and this protection can be given by manganese and thus the DNA when can be made to heal quickly. The protection for the proteins responsible for the DNA repair is given by oxidative layer. Thus when the DNA repair proteins are protected from being damaged, any problem to the DNA can be repaired by the proteins that are responsible. If incase the proteins responsible for the repair are not protected and when any lesions occur then repairing this would turn into a big issue because of the fact that the proteins that are responsible for the repair are not protected and thus they would have also damaged along with the DNA. Thus the DNA repair system becomes highly efficient only when the manganese ions are present.
