Starting from its formation as a cosmic particle, the earth is exposed to
various types of radiation. With gradual cooling and environmental modifications, it
started supporting life, first in the form of viruses and bacteria. So, radiation-resistant
microorganisms are thought to be among the Earth’s ancient life forms. But, however,
it is relatively an unexplored arena of research today. Though the members are few,
radiation-resistant bacteria belong to a phylogenetically diverse community and their
degree of withstanding the dose of radiation is also diverse. In most of the cases, the
resistance mechanism involved survival from DNA damage and protein oxidation. In
this chapter, we will discuss the diversity of radiation-resistant bacteria explored so far
with their generalized mechanisms of resistance, along with the basic concept of
radiation and radiation-induced damages.
Keywords: Radiation resistance, Deinococcus, Radiation induced DNA damage, DNA repair.
