【摘要】 【目的】检测在耐辐射球菌抵抗外来辐射和氧自由基的过程中,锰离子转运蛋白基因(DR1709和DR2523)是否发挥了作用。探讨锰离子、锰离子转运蛋白基因与耐辐射球菌辐射抗性之间的关系。【方法】分别构建这两个基因的突变体。对突变体和野生型进行紫外线照射和过氧化氢处理。对处理后的菌株存活率进行分析。【结果】DR2523被突变以后,耐辐射球菌在tryptone-glucose-yeast extract(TGY)培养液中的生长受影响很小。而DR1709突变体M1709在对数生长阶段的生长速度远低于野生型。用紫外线和过氧化氢处理以后,尽管野生型的存活率高于DR2523突变体M2523,不过二者的差别并不大。但是M1709在紫外线和过氧化氢处理后的存活率远低于野生型。【结论】在耐辐射球菌抵御辐射和氧自由基损伤的过程中,DR2523和DR1709都在不同程度上发挥了作用。耐辐射球菌从培养基吸收锰离子分多步骤进行。在DR2523被突变以后,其部分功能可能被DR2283和/或DR2284所取代。更多还原

【Abstract】 [Objective] The primary objective of this study was to identify whether the manganese ions [Mn(Ⅱ)] transporter genes DR1709 and DR2523 played roles in Deinococcus radiodurans’s radiation resistance. The second objective was to study the relationships among manganese ions,manganese ions transporter genes and the bacterial radioresistance. [Methods] We constructed mutants of DR1709 and DR2523. The wild type and the mutants were treated with UV and hydrogen peroxide (H2O2). The survival fractions of the three strains were analyzed. [Results] Disruption of DR2523 hardly affected the growth of D. radiodurans in tryptone-glucose-yeast extract (TGY) broth. But at each site of the logarithmic stages,the OD 600 values of DR1709 mutant (M1709) were much lower than those of the wild type. After being treated with H2O2 and UV,the survival rates of M1709 cells at each dose were much lower than those of the wild type. However,the DR2523 mutant (M2523) and wild type had the similar appearance after being treated with H2O2 and UV,though the wild type had the higher survival than M2523. [Conclusion] DR1709 and DR2523 could protect D. radiodurans from irradiation and superoxide radicals. In D. radiodurans,transporting Mn(Ⅱ) from the medium was possibly controlled by several different steps. The roles of DR2523 might be partially substituted by DR2283 and/or DR2284,while no other genes could exercise the similar function as DR1709.更多还原