摘要：Microorganisms with the ability to survive high doses of radiation are known as radiation-resistant extremophiles. This study attempts to demonstrate the diversity of microorganisms resistant to ultraviolet radiation (UVR) in the natural environment in order to investigate the molecular and physiological mechanisms by which these microorganisms survive under extreme radiation. We hypothesized that topsoil from elevated land (hills) would reveal a diverse variety of UVR-resistant extremophiles with modulated proteins/enzymes. A total of 10 different UV-C (UV subtype-C)-resistant extremophiles—UVP1, UVP3, UVP4, UVR1, UVR3, UVR4, UVR5a, UV20hr, YLP1, and BR2—were isolated and identified using 16S rRNA sequences for nearest homologues. All the isolates showed prolonged resistance against UV-C: 3.44 x 105 - 2.74 x 106 J/m2. Phylogenetic analysis between and within the UVR isolates revealed their relationship with other soil microorganisms using different outgroups. A unique pattern of protein expression at 25-50kDa was observed on SDS-PAGE under UVR and non-UVR from six prominent UVR isolates. Current studies are finding extreme UV-C-resistant in naturally occurring microorganisms found in stress-free environments.
