耐辐射球菌基因DR1709与DR2523的突变分析

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。

Disruption of manganese ions [Mn (II)] transporter genes DR1709 or DR2523 in extremely radio-resistant bacterium Deinococcus radiodurans

[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 trunsporter 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 ( H2 O2 ).The survival fractions of the three swains 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 OD600 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 H2 O2 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 contrlled 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.