Abstract This study develops general predictive models for the ultraviolet (UV) radiation dose–response behavior of Bacillus subtilis spores to solar UV irradiation that occurs in the environment and broadband UV irradiation used in water disinfection systems. The approach is demonstrated using previously obtained experimental survival rates for B. subtilis spores deposited on dry surfaces as well as in water and exposed to both narrow band UV radiation as well as broadband UV irradiation from solar exposure and disinfectant lamps. Results are modeled to derive predicted survival rates for spores as a function of irradiance intensity and wavelength, capability for repair, and depletion of available sites for UV damage. The essential features of the approach are expression of the inactivation action spectrum in terms of the probability of an incident photon being absorbed and forming a dimer lesion, and expression of the spore survival as a cumulative binomial distribution for damage. The results provide increased accuracy in estimating dispersed biological hazards, and evaluating the effectiveness of UV air and water disinfectant systems. In addition, the approach for the first time explains the observed reduced inactivation rate in a repair-capable strain compared with a sensitive, repair-deficient strain by accounting for the depletion of available lesion-forming sites due to increasing DNA damage.

中文翻译：

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预测暴露于宽带和太阳紫外线的枯草芽孢杆菌孢子的灭活

摘要 本研究开发了枯草芽孢杆菌孢子对环境中发生的太阳紫外线照射和水消毒系统中使用的宽带紫外线照射的紫外线 (UV) 辐射剂量响应行为的通用预测模型。该方法是使用先前获得的枯草芽孢杆菌孢子的实验存活率来证明的，这些孢子沉积在干燥的表面和水中，并暴露于窄带紫外线辐射以及来自太阳照射和消毒灯的宽带紫外线辐射。结果被建模以推导出孢子的预测存活率，作为辐照强度和波长、修复能力和紫外线损伤可用位点的消耗的函数。该方法的基本特征是根据入射光子被吸收并形成二聚体损伤的概率来表达灭活作用谱，并将孢子存活表达为损伤的累积二项式分布。结果在估计分散的生物危害和评估紫外线空气和水消毒剂系统的有效性方面提供了更高的准确性。此外，该方法首次解释了观察到的具有修复能力的菌株与敏感的修复缺陷菌株相比灭活率降低的原因，原因是由于 DNA 损伤增加导致可用损伤形成位点的消耗。结果在估计分散的生物危害和评估紫外线空气和水消毒剂系统的有效性方面提供了更高的准确性。此外，该方法首次解释了观察到的具有修复能力的菌株与敏感的修复缺陷菌株相比灭活率降低的原因，原因是由于 DNA 损伤增加导致可用损伤形成位点的消耗。结果在估计分散的生物危害和评估紫外线空气和水消毒剂系统的有效性方面提供了更高的准确性。此外，该方法首次解释了观察到的具有修复能力的菌株与敏感的修复缺陷菌株相比灭活率降低的原因，原因是 DNA 损伤增加导致可用损伤形成位点的消耗。