Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, People's Republic of China.
Institute of Biology, Yibin University, Yibin, 644007, Sichuan, People's Republic of China.
Curr Microbiol. 2016 Jun;72(6):767-75. doi: 10.1007/s00284-016-1015-y. Epub 2016 Feb 26.
To explore the radiation-resistance mechanisms in bacteria, a radiation-resistant strain SC1204 was isolated from the surrounding area of a (60)Co-γ radiation facility. SC1204 could survive up to 8 kGy dose of gamma irradiation and was identified as Micrococcus luteus by phylogenetic analysis of 16S rRNA gene sequences. Its proteomic changes under 2-kGy irradiation were examined by two-dimensional electrophoresis followed by MALDI-TOF-TOF/MS analysis. The results showed that at least 24 proteins displayed significant changes (p < 0.05) at expression level under the radiation stress, among which 22 were successfully identified and classified into the major functional categories of metabolism, energy production and conservation, translation, ribosomal structure, and biogenesis. Among these proteins, leucyl aminopeptidase involved in synthesis of glutathione was the most abundant induced protein during postirradiation recovery, indicating that anti-oxidation protection was the most important line of defense in SC1204 against radiation. The next abundant protein was phosphoribosyl aminoimidazole carboxamide formyltransferase/IMP cyclohydrolase (AICAR Tfase/IMPCH), the key enzyme in the biosynthetic pathway of purine that is anti-radiation compound. Other proteins changing significantly (p < 0.05) after radiation exposure included urocanate hydratase, dihydrolipoyl dehydrogenase, succinyl-CoA synthetase subunit alpha, phosphoglycerate kinase, cell division protein FtsZ, elongation factor Ts and Tu, translation elongation factor Tu and G, 30S ribosomal protein S1, histidyl-tRNA synthetase, and arginyl-tRNA synthetase, which were considered to be the key proteins in urocanate metabolism, tricarboxylic acid cycle, glycolysis, cell division process, and synthesis process of proteins. Therefore, these proteins may also play important roles in radiation resistance in M. luteus.
为了探索细菌的辐射抗性机制，从钴-γ辐射装置周围环境中分离到一株耐辐射菌株 SC1204。SC1204 可以在 8 kGy 的γ射线照射下存活，并通过 16S rRNA 基因序列的系统发育分析鉴定为微球菌。通过二维电泳结合 MALDI-TOF-TOF/MS 分析，研究了其在 2 kGy 照射下的蛋白质组变化。结果表明，在辐射胁迫下，至少有 24 种蛋白质的表达水平发生了显著变化（p<0.05），其中 22 种蛋白质成功鉴定，并分类为代谢、能量产生和保存、翻译、核糖体结构和生物发生等主要功能类别。在这些蛋白质中，参与谷胱甘肽合成的亮氨酰氨肽酶是辐照后恢复过程中最丰富的诱导蛋白，表明抗氧化保护是 SC1204 抵抗辐射的最重要防线。下一个丰富的蛋白质是磷酸核糖基氨基咪唑羧酰胺甲酰基转移酶/IMP 环水解酶（AICAR Tfase/IMPCH），它是嘌呤生物合成途径中的关键酶，是一种抗辐射化合物。其他在辐射暴露后发生显著变化（p<0.05）的蛋白质包括尿刊酸水解酶、二氢乳清酸脱氢酶、琥珀酰-CoA 合成酶亚基α、磷酸甘油酸激酶、细胞分裂蛋白 FtsZ、延伸因子 Ts 和 Tu、翻译延伸因子 Tu 和 G、30S 核糖体蛋白 S1、组氨酸-tRNA 合成酶和精氨酰-tRNA 合成酶，这些蛋白质被认为是尿刊酸代谢、三羧酸循环、糖酵解、细胞分裂过程和蛋白质合成过程中的关键蛋白。因此，这些蛋白质在微球菌的辐射抗性中可能也发挥着重要作用。
