本研究从我国夏季高温、强辐射的新疆塔里木地区采集样品，进行了细菌的分离、纯化及分类鉴定。用丙酮萃取法抽提39个分离菌株的培养产物，通过高效液相色谱和紫外-可见吸收光谱分析其主要组分；利用λ噬菌体紫外诱导系统研究抽提物清除自由基的能力。高效液相色谱和紫外-可见吸收光谱分析的结果表明：多数分离菌株丙酮提取物的主要组分为类胡萝卜素物质。λ噬菌体紫外诱导系统抑制实验结果表明：29个菌株的丙酮提取物对λ噬菌体的紫外诱导具有不同程度的抑制作用，抑制率最高达81%。不同菌株之间的比较试验显示不同属细菌的丙酮提取物对λ噬菌体紫外诱导系统的抑制效果存在很大差异，其中以Methylobacterium的抑制作用最强；不同颜色菌株提取物的抑制效果也出现较大差异；Koanria中不同颜色菌株的抑制效果也有类似结果。本文为类胡萝卜素可能是该类细菌具有抗辐射能力的内因之一提供了直接证据。同时，也证实了λ噬菌体紫外诱导系统是一种很好的探讨细菌抗辐射机理的研究模型。

In this study, the bacterium strains from Takramagan in Xinjiang, which was characteristic with high temperature and strong ultraviolet (UV) radiation in summer, were isolated, purified and identified. The acetone extracts of 39 isolated strains were measured by HPLC and UV-visible detection and their free radical scavenging abilities were determined using UV induction of bacteriophage λ, respectively. The results showed that the main compounds of most extracts were carotenoids and the extracts of 29 strains could protect the bacteriophage λ against UV radiation with different efficiency, the maximum inhibitory rate of which can be up to 81%. By comparison of the strains, it was found that the strains in different genus were obviously different in the protective abilities against UV radiation, and the strain of Methylobacterium showed the strongest among them. Strains with different colors belonging to different genus showed different effect, so did the strains of Kocuria. This paper revealed that carotenoid was one of the key factors for protecting the strains against UV radiation. Furthermore, the UV induction of bacteriophage λ proved to be a very useful model for studying the radiation resistance of different substance.