中文摘要：

研究室经过对枯草芽孢杆菌黑色变种进行了两次中子辐照,一次γ辐照和一次紫外线辐照,筛选得到了一株辐射抗性较强的菌株,称为耐辐射株。为了系统地考察这株耐辐射株的辐照抗性,分别以芽孢和营养体为材料,研究了其对中子、脉冲X光和紫外线的耐受性。结果显示,这株耐辐射株与原菌相比,对不同射线的耐受性都有不同程度的提高。但对于不同的辐照,其耐受性上升幅度不同,而且芽孢和营养体状态对辐射耐受的表现也不一致。总的来说,芽孢对各种辐射的耐受性增长相对较少,对不同辐照剂量的表现也较一致。耐辐射株营养体对不同射线在不同剂量下的耐受性表现差异较大：对中子辐照耐辐射株营养体的存活率是原菌的4~5倍,而对脉冲X射线辐照,在各剂量下耐辐射株的抗性表现较一致,大约是原菌的200倍;对UVC辐照耐辐射株营养体比原菌耐受能力,在不同剂量下差异较大,分别提高2.5~66倍。这些结果表明,这株耐辐射株对不同的射线都具有较强的辐射抗性能力,这种能力可能与其DNA损伤修复水平和细胞周期有关。

英文摘要：

A strong radiation resistance strain was screened,known as Bacillus subtilis radioresistant strain,after twice neutron irradiation,once γ–ray and once UV radiation on Bacillus subtilis var niger in the laboratory.In order to study the strain resistance to different radiation systematically,spores and vegetative cells were used as the research materials,and neutron,pulse X-ray and UVC were used as radiation resource.Results showed that compared with the original strain,the radioresistant strain tolerance to various rays has increased in varying degrees.To different irradiation,the increase rate of tolerance is different,and for spores and vegetative cells,the radiation tolerance is inconsistent.The radioresistant strain spores have a relatively small increase in radiation tolerance,and have the same performance in different radiation doses.Radioresistant strain vegetative cells have a great diversity in radiation tolerance to different rays at different doses.The radioresistant strain vegetative cells survival rate is 4~5 times the original strain after neutron irradiation,and 200 times after the pulse X-ray irradiation,the same resistance in various X-ray doses,while is 2.5~66 times,a great diversity at different UVC doses.It can be concluded that Bacillus subtilis radioresistant strain has a strong radiation resistant ability to the different radiations.The ability may be relevant with the cell repair level to DNA damage and cell cycle.