1. Diversity of ionizing radiation-resistant bacteria obtained from the Taklimakan Desert.
- Author
-
Yu LZ, Luo XS, Liu M, and Huang Q
- Subjects
- Actinobacteria classification, Actinobacteria genetics, Bacteria genetics, Bacteria isolation & purification, Catalase metabolism, China, Genetic Variation, Gram-Positive Bacteria classification, Gram-Positive Bacteria genetics, Gram-Positive Bacteria isolation & purification, Gram-Positive Bacteria radiation effects, Phenotype, Phylogeny, Proteobacteria classification, Proteobacteria genetics, RNA, Ribosomal, 16S genetics, Reactive Oxygen Species metabolism, Bacteria classification, Bacteria radiation effects, Desert Climate, Gamma Rays, Radiation Tolerance, Soil Microbiology
- Abstract
So far, little is known about the diversity of the radiation-resistant microbes of the hyperarid Taklimakan Desert. In this study, ionizing radiation (IR)-resistant bacteria from two sites in Xinjiang were investigated. After exposing the arid (water content of 0.8 ± 0.3%) and non-arid (water content of 21.3 ± 0.9%) sediment samples to IR of 3000 Gy using a (60)Co source, a total of 52 γ-radiation-resistant bacteria were isolated from the desert sample. The 16S rRNA genes of all isolates were sequenced. The phylogenetic tree places these isolates into five groups: Cytophaga-Flavobacterium-Bacteroides, Proteobacteria, Deinococcus-Thermus, Firmicutes, and Actinobacteria. Interestingly, this is the first report of radiation-resistant bacteria belonging to the genera Knoellia, Lysobacter, Nocardioides, Paracoccus, Pontibacter, Rufibacter and Microvirga. The 16s rRNA genes of four isolates showed low sequence similarities to those of the published species. Phenotypic analysis showed that all bacteria in this study are able to produce catalase, suggesting that these bacteria possess reactive oxygen species (ROS)-scavenging enzymes. These radiation-resistant bacteria also displayed diverse metabolic properties. Moreover, their radiation resistances were found to differ. The diversity of the radiation-resistant bacteria in the desert provides further ecological support for the hypothesis that the ionizing-radiation resistance phenotype is a consequence of the evolution of ROS-scavenging systems that protect cells against oxidative damage caused by desiccation., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2015
- Full Text
- View/download PDF