Abstract：
The Taklimakan Desert located in China is the second-largest shifting sand desert in the world and is known for its harsh conditions. Types of γ-rays or UV radiation-resistant bacterial strains have been isolated from this desert. However, there is no information regarding the proportions of the radiation-resistant strains in the total culturable microbes. We isolated 352 bacterial strains from nine sites across the Taklimakan Desert from north to south. They belong to Actinobacteria, Firmicutes, Proteobacteria, and Bacteroidetes. The phylum Actinobacteria was the most predominant in abundance and Firmicutes had the highest species richness. Bacteroidetes had the lowest abundance and was found in four sites only, while the other three phyla were found in every site but with different distribution profiles. After irradiating with 1000 J/m2 and 6000 J/m2 UV-C, the strains with survival rates higher than 10% occupied 72.3% and 36.9% of all culturable bacteria, respectively. The members from Proteobacteria had the highest proportions, with survival rates higher than 10%. After radiation with 10 kGy γ-rays, Kocuria sp. TKL1057 and Planococcus sp. TKL1152 showed higher radiation-resistant capabilities than Deinococcus radiodurans R1. Besides obtaining several radiation-resistant extremophiles, this study measured the proportions of the radiation-resistant strains in the total culturable microbes for the first time. This study may help to better understand the origin of radioresistance, especially by quantitatively comparing proportions of radiation-resistant extremophiles from different environments in the future.
摘要：
位于中国的塔克拉玛干沙漠是世界上第二大流沙沙漠，以其恶劣的条件而闻名。已从该沙漠中分离出类型的γ射线或抗紫外线辐射的细菌菌株。然而,没有关于抗辐射菌株在总可培养微生物中的比例的信息。我们从北到南，从塔克拉玛干沙漠的9个地点分离出352个细菌菌株。它们属于放线菌,Firmicutes,变形杆菌,和拟杆菌。放线菌门的数量最多，而Firmicutes的物种丰富度最高。拟杆菌的丰度最低，仅在四个地点发现，而其他三个门在每个地点都有发现，但分布特征不同。用1000J/m2和6000J/m2UV-C照射后，存活率高于10%的菌株占所有可培养细菌的72.3%和36.9%，分别。来自变形杆菌的成员比例最高，存活率高于10%。用10kGyγ射线照射后，Kocuriasp.TKL1057和Planococcussp。TKL1152显示出比耐放射球菌R1更高的抗辐射能力。除了获得几种抗辐射极端微生物外，这项研究首次测量了抗辐射菌株在总可培养微生物中的比例。这项研究可能有助于更好地理解辐射抗性的起源，特别是通过定量比较未来来自不同环境的抗辐射极端微生物的比例。
