摘要
目的研究缩短红杆菌(Rubrobacter sp.)YIM93620和YIM9941对紫外线、γ射线照射及低能碳离子注入后的生物学效应,揭示二者的辐射抗性及耐辐射机制。方法分别对这两株菌进行不同剂量的紫外、γ射线照射及低能碳离子注入,以E.coli K-2为阴性对照,绘制致死率曲线;检测DNA损伤修复(Rec A基因)以及辐射过程中耐辐射微生物蛋白酶变化。结果 YIM93620和YIM9941在UV辐照剂量达30 J/m2时,与阴性对照菌比较(<1%),受试菌株存活率均高达95%以上。在γ辐照剂量达0.1k Gy时,阴性对照菌株的生存率已经低至21%,而阳性对照株和受试菌株均未见死亡。YIM 93620基因组内Rec A和RecR表达较高(P<0.01),而YIM9941基因组内RecR表达较高(P<0.01)。YIM 93620和YIM 9941菌体细胞中含有较高的SOD活性和CAT活性,其中YIM93620细胞内的SOD活性比E.coli K-12高5.8倍,CAT活性高26.8倍。结论 YIM 93620和YIM 9941两株菌生长均有强的耐UV和γ射线特性,与其细菌的重组修复和抗氧化特性有关。
Objective To identify the biological effects of ultraviolet,γ-ray irradiation and C+ion implantation of low energy on Rubrobacter sp. YIM93620 and YIM9941,and investigate the radio-resistant mechanisms for both strains. Methods E. coli K-12 was used as a negative control. Both strains were exposed to UV,γ-ray radiation and C+ion implantation of different doses,and the lethality rate curves were plotted for researching the biological effects. The expressions of Rec A genes and protein,and the level of anti-oxidation related enzymes were tested. Results Compare to E. coli K-12,both strains showed strong resistance to UV and γ-ray radiation. Strain YIM93620 and YIM9941 reached the highest survival rate of 95% at 30 J/m2 UV( vs. E. coli K-12,< 1%) and 100% at 0. 1 k Gy γ-ray radiation( vs. E. coli K-12,< 21%). Strain YIM 93620 showed high expression in Rec A and RecR genes( vs. E. coli K-12,P < 0. 01),and strain YIM9941 showed high expression in RecR genes( vs. E. coli K-12,P < 0. 01). There were also higher activities of SOD and CAT in both strains. In YIM93620 the activity of SOD was higher 5. 8 times than in E. coli K-12,activity of CAT was higher 26. 8 times. Conclusion YIM93620 and YIM9941 have the radio-resistant characters to UV and γ-ray exposure and which are associated with the capability of DNA repairing and anti-oxidation.
引文
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