Bohrerova Z, Linden K G
Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708, USA.
J Appl Microbiol. 2006 Nov;101(5):995-1001. doi: 10.1111/j.1365-2672.2006.03023.x.
Ultraviolet (UV) irradiation for drinking water treatment was examined for inactivation and subsequent dark and photo-repair of Mycobacterium terrae.
UV sources tested were low pressure (monochromatic, 254 nm) and medium pressure (polychromatic UV output) Hg lamps. UV exposure resulted in inactivation, and was followed by dark or photo-repair experiments. Inactivation and repair were quantified utilizing a molecular-based endonuclease sensitive site (ESS) assay and conventional colony forming unit (CFU) viability assay. Mycobacterium terrae was more resistant to UV disinfection compared to many other bacteria, with approximately 2-log reduction at a UV fluence of 10 mJ cm(-2) ; similar to UV inactivation of M. tuberculosis. There was no difference in inactivation between monochromatic or polychromatic UV lamps. Mycobacterium terrae did not undergo detectable dark repair. Photo-repair resulted in recovery from inactivation by approximately 0.5-log in less than 30 min for both UV lamp systems.
Mycobacterium terrae is able to photo-repair DNA damage within a short timeframe. The number of pyrimidine dimers induced by UV light were similar for Escherichia coli and M. terrae, however, this similarity did not hold true for viability results.
There is no practical difference between UV sources for disinfection or prevention of DNA repair for M. terrae. The capability of M. terrae to photo-repair UV damage fairly quickly is important for wastewater treatment applications where disinfected effluent is exposed to sunlight. Finally, molecular based assay results should be evaluated with respect to differences in the nucleic acid content of the test micro-organism.
研究紫外线（UV）照射用于饮用水处理时对土地分枝杆菌的灭活作用以及随后的暗修复和光修复情况。
测试的紫外线光源为低压（单色，254纳米）和中压（多色紫外线输出）汞灯。紫外线照射导致细菌灭活，随后进行暗修复或光修复实验。利用基于分子的内切酶敏感位点（ESS）测定法和传统的菌落形成单位（CFU）活力测定法对灭活和修复进行定量分析。与许多其他细菌相比，土地分枝杆菌对紫外线消毒更具抗性，在紫外线通量为10 mJ cm(-2) 时约有2个对数级的减少；这与结核分枝杆菌的紫外线灭活情况相似。单色或多色紫外线灯在灭活效果上没有差异。土地分枝杆菌未发生可检测到的暗修复。对于两种紫外线灯系统，光修复在不到30分钟内使细菌从灭活状态恢复约0.5个对数级。
土地分枝杆菌能够在短时间内对DNA损伤进行光修复。大肠杆菌和土地分枝杆菌由紫外线诱导产生的嘧啶二聚体数量相似，然而，在活力结果方面这种相似性并不成立。
对于土地分枝杆菌的消毒或防止DNA修复，紫外线光源之间没有实际差异。土地分枝杆菌能够较快地对紫外线损伤进行光修复，这对于消毒后的废水暴露于阳光下的废水处理应用很重要。最后，应根据测试微生物核酸含量的差异来评估基于分子的测定结果。
