干旱区生态环境知识资源中心

Organisms in hot, arid environment have to cope with adverse life conditions such as desiccation, temperature and lack of nutrients. The phylogenetic diversity of ultra-violet (UV) radiation resistant bacteria from desert soil was investigated by culture and molecular-based analysis. The bacterial strains were characterized for their tolerance to UV doses, salt concentration and heavy metals. The effect of UV radiation (UVR) on cellular lipids and proteins was studied by lipid peroxidation and protein carbonylation assay. 9 UV resistant bacteria were isolated and identified through biochemical tests and 16S rRNA sequencing. These bacterial strains were grouped into four phyla: Firmicutes, Proteobacteria, Deinococcus-Thermus and Actinobacteria. The genus Deinococcus was found to be resistant to high UV dosage in comparison to other genera, as indicated by maximum survival rate. The bacteria were found to grow at a wide range of temperature and pH, resistant to high salt concentration and various metal ions. The UV resistant selected strains exhibited minor damages to proteins and lipids as a result of exposure to UV radiation as compared to Escherichia coli (ATCC 10536), a UV sensitive bacteria. The results indicated that these microbes might harbor a sophisticated phenotypic character and molecular repair mechanism that can prolong their survival under extreme radiation.