西藏土壤中耐辐射阿氏芽胞杆菌T61的分离和鉴定

Isolation and identification of radiation resistant Bacillus aryabhattai T61 from Tibetan soil

摘要:

【目的】对分离自西藏土样的菌株T61进行分离、鉴定和UV辐射抗性分析。【方法】对菌株T61进行形态和生理生化鉴定；对16S rRNA基因进行克隆和测序，构建系统进化树；测定脂肪酸成分和GC含量，将T61与最相近种进行DNA-DNA杂交；测定T61的UV辐射抗性曲线。【结果】T61细胞杆状，长度约为2 mm，直径约为1 mm，革兰氏阳性，可产生内生孢子。G+C含量为38.02%。脂肪酸主要成分是C14:0 iso、C15:0 iso和C15:0 anteiso。16S rRNA基因与阿氏芽胞杆菌B8W22T和巨大芽胞杆菌IAM13418T相似度最高，分别达到99.93%和99.53%。DNA-DNA杂交分析表明，T61与阿氏芽胞杆菌B8W22T的相似度为81.4%，而与巨大芽胞杆菌IAM13418T的相似度只有50.3%。UV辐射抗性分析显示，T61 D10为100 J/m2，远高于辐射敏感的大肠杆菌K12和枯草芽孢杆菌等菌株。【结论】菌株T61是一株阿氏芽胞杆菌，命名为Bacillus aryabhattai T61，其对UV辐射具有较强的抗性。

Abstract:

[Objective] To identify strain T61 which was isolated from Tibetan soil and analyze its radiation resistance. [Methods] First, investigate the morphological and biochemical characteristics of T61; Second, amplify the sequence of 16S rRNA gene and construct the phylogenetic tree; Third, determine compositions of fatty acids, DNA G+C content and DNA-DNA hybridization; Finally, analyze T61 survival curve after exposure to UV radiation. [Results] T61 cells were rod-shaped, 2 μm in length, 1 μm in diameter, gram-positive and endospore-forming. Strain T61 had a G+C content of 38.02%. The main Fatty acids were C14:0 iso, C15:0 iso and C15:0 anteiso. Phylogenetic analysis of the 16S rRNA gene showed that strain T61 had 99.93% and 99.53% similarities with Bacillus aryabhattai B8W22T and Bacillus megaterium IAM13418T, respectively. At the whole genome level, the DNA-DNA relatedness between T61 and Bacillus aryabhattai B8W22T was 81.4%, but only 50.3% with Bacillus megaterium IAM13418T. D10 values of T61 after exposure to UV was 100 J/m2, much higher than those of radiation-sensitive Escherichia coli K12 and B. subtilis. [Conclusion] Strain T61 was highly resistant to UV radiation. It was identified as Bacillus aryabhattai species, and was proposed the name Bacillus aryabhattai T61.