可培养细菌多样性及抗辐射-抗氧化相关性特征——以库姆塔格沙漠东缘为例

对库姆塔格沙漠东缘可培养细菌进行系统发育学多样性研究的基础上，对菌株的抗辐射和抗氧化能力进行筛选，利用辐射或氧化胁迫后细菌的存活率进行二者耦联关系的研究.研究表明，pH值、TOC和TN是影响库姆塔格沙漠东缘中可培养细菌群落结构的主要因素；分离出的105株细菌分别归属于放线菌门（Actinobacteria）、拟杆菌门（Bacteroidetes）、厚壁菌门（Firmicutes）和变形菌门（Proteobacteria），在可培养细菌数量（9.96×10⁵CFU/g）和物种丰富度（9个属共72株菌）方面放线菌门均为最优势的门；除拟杆菌门以外，归属于放线菌门、厚壁菌门和变形菌门的可培养细菌中都筛选出了兼具抗辐射-抗氧化的菌株.通过抗辐射抗氧化性能研究表明可培养细菌的抗辐射能力与抗氧化能力具有一定的正相关性；UV-C辐照强度的D₁₀（致死率为10%）剂量高于100J/m²的菌株占可培养细菌总数的21.3%，过氧化氢耐受浓度的D₁₀剂量高于10mmol/L的菌株占70.2%，其中放线菌门的3株细菌K4-10、K5-3和K2-40兼具有很强的抗辐射和抗氧化能力.

The diversity of culturable bacteria in the eastern edge of Kumtag Desert,and the characteristic of their radiation-resistance and anti-oxidation,including the correlation and coupling of these capacities

This study investigated the phylogenetic diversity of culturable bacteria in the eastern edge of Kumtag Desert, and then screened the radiation-resistant and oxidant-resistant strains via their survival rate after radiation and oxidation treatments. The correlations between their survival rates under the two treatments were also used to find the coupling relationship between the two capacities of bacteria. The results showed that pH, TOC, and TN were the key factors that influenced the community structure of culturable bacteria in the desert environment. In total, 105 bacteria strains were isolated from the eastern edge of the Kumtag Desert affiliated to the phyla of Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. Actinobacteria was the most dominant phylum in culturable bacteria in both abundance (9.96×10⁵CFU/g) and species richness (72 strains from 9 genera). The culturable bacterial strains from the phyla Actinobacteria, Firmicutes, and Proteobacteria, were found to have both two capabilities to resist radiation and oxidation, but not bacterial strains from the phylum Bacteroidetes. The strains with D₁₀ dose (with survival rate greater than 10%) were higher than 100J/m² of UV-C radiation and accounted for 21.3% of the total culturable bacteria. The proportion of the anti-oxidant strains with D₁₀ dose higher than 10mmol/L H₂O₂ accounted for 70.2%. The study showed that the two capabilities of culturable bacteria have positive correlation characteristics. Three strains from the actinobacteria, K4-10, K5-3, and K2-40, have very high capabilities to resist both radiation and oxidation.