Study on the resistance of haloferax radiotolerans, an extreme Halophilic archaebacterium from Uromia lake against ultraviolet (UV) light and 60Co gamma-rays

In this work, the capacity of an extreme halophilic archaebacterium, isolated from Uromia lake, Haloferax radiotolerans to withstand the lethal effects of ultraviolet light (UV),and 60Co r-rays has been studied. The resistibility of this organism against the DNA-damaging agents was evaluated by calculating of the survival fractions at different dose rates of W and 60Co r-rays radiations and compared with those of Escherichia coli B/r (a radioresistant strain of E. coli). D37 values for Haloferax radiotolerans and E. coli B/r were 23 1, and 9 J/m2 , respectively, by exposure to the UV light. They were 645, and 99 Gy, respectively, by exposure to 60Co r-rays. Against these agents, Haloferax radiotolerans shows much more resistance compare to that of E. coli B/r. This is categorized as the first report of resistibility in the member of Archaea