一株新的耐辐射菌Deinococcus guangxiensis sp.nov.的分离鉴定及耐辐射特性分析

摘要：【目的】从广西大学辐射中心辐射源附近被常年辐射的水样中分离并鉴定出新的耐辐射菌株，并对其耐辐射特性进行研究。【方法】通过GBM培养基分离培养得到一株新的耐辐射菌株，命名为WGR700T。应用生理生化试验，脂肪酸含量，(G+C) mol％含量测定以及16S rRNA序列同源性分析等方法对菌株进行鉴定，同时对WGR700T的耐辐射特性进行分析。【结果】菌株WGR700T为革兰氏阴性，杆状，没有鞭毛，不能运动，厌氧并能产生红色素。最佳生长温度和PH分别为37℃和pH7.0，主要的呼吸醌是MK-8，细胞壁内还有鸟氨酸，主要脂肪酸为16:1ω7c, 16:0, 15:1ω6c, iso-15:0和 iso-17:0。G+C含量为64.7mol%。菌株WGR700T具有很强的UV(>728 J/m2)和电离辐射抗性(D10 = 9.8 kGy)。菌株WGR700T和奇异球菌属（Deinococcus）内其它菌种16S rRNA有很高的相似性（87.1-95.6%）。【结论】根据16S rRNA及生理生化特征区别，菌株WGR700T应是奇异球菌属的一个新种，命名为Deinococcus guangxiensis sp. nov. 模式菌株为WGR700T(= CGMCC1.7045T =CICC 10360T = JCM 15082T)。

Isolation and identification of a new radiation-resistant bacterium Deinococcus guangxiensis sp.nov. and analysis of its radioresistant character

Objective] To isolate and identify a new ionizing-radiation resistant strain capable of surviving under highly ionizing radiation conditions as UV and gamol/La radiation and to characterize its radioresistant properties. Methods] The isolates were sampled from Radiation Centre of Guangxi University, Nanning, China, and the medium used for isolation and cultivation of the bacterium was General Bacterial Medium (GBM). The new ionizing-radiation resistant strain WGR700T was identified by its morphology, biochemical and physiological characteristics, fatty acids, G+ C content of DNA, UV and gamol/La radiation resistance and 16S rRNA gene sequence homology. Results] The strain WGR700T is of rod-shape, Gram-negative, non- spore-forming, non motile, aerobic and red-pigmented. The optimum temperature and pH for strain WGR700T growth is 37℃ and pH7.0, respectively. The predominant respiratory quinone is MK-8 and its cell well contains ornithine. The major cellular fatty acids found in the cell wall are 16: lω7c, 16:0, 15:la6c, iso-15:0 and iso-17:0. DNA of strain WGR700T had a G + C content of 64.7mol% . WGR700T was highly resistant to UV ( > 728 J/m2) and gamol/La radiation ( D10 = 9.8 kGy). Phylogenetic analysis of the 16S rRNA gene sequences showed 87.1 - 93.6% similarities with other recognized Deinococcus species. Conclusion] Based on the high 16S rRNA gene sequence divergence and phenotypic differences, it is proposed that the new isolated strain should be classified as a novel member in the genus Deinococcus with the name Deinococcus guangxiensis sp. nov. The type strain is WGR700T( = CGMCC 1.7045T = CICC 10360T = JCM 15082T) .