Wavelength dependence of biological damage induced by UV radiation on bacteria
- 1.7k Downloads
The biological effects of UV radiation of different wavelengths (UVA, UVB and UVC) were assessed in nine bacterial isolates displaying different UV sensitivities. Biological effects (survival and activity) and molecular markers of oxidative stress [DNA strand breakage (DSB), generation of reactive oxygen species (ROS), oxidative damage to proteins and lipids, and the activity of antioxidant enzymes catalase and superoxide dismutase] were quantified and statistically analyzed in order to identify the major determinants of cell inactivation under the different spectral regions. Survival and activity followed a clear wavelength dependence, being highest under UVA and lowest under UVC. The generation of ROS, as well as protein and lipid oxidation, followed the same pattern. DNA damage (DSB) showed the inverse trend. Multiple stepwise regression analysis revealed that survival under UVA, UVB and UVC wavelengths was best explained by DSB, oxidative damage to lipids, and intracellular ROS levels, respectively.
KeywordsUV radiation Bacteria Inactivation Oxidative stress
The authors would like to thank the anonymous reviewers and editors who provided helpful criticism and suggestions which greatly contributed to improve the original manuscript. Acknowledgments are due to Francisco Coelho and Abel Ferreira for assistance in UV intensity measurements and to Prof. Rosário Correia (Physics Department, Universiy of Aveiro) for reviewing the manuscript. Financial support for this work was provided by CESAM (Centre for Environmental and Marine Studies, University of Aveiro) and the Portuguese Foundation for Science and Technology (FCT) in the form of a PhD grant to A. L. Santos (SFRH/BD/40160/2007) and a post-Doctoral grant to I. Henriques (SFRH/BPD/63487/2009).
- Friedberg EC, Walker GC, Siede W (1995) DNA repair and mutagenesis. American Society of Microbiology Press, Washington, DCGoogle Scholar
- Jagger J (1985) Solar UV actions on living cells. Praeger Publishing, New YorkGoogle Scholar
- Mitchell DL, Karentz D (1993) The induction and repair of DNA photodamage in the environment. In: Young AR, Bjorn LO, Moan J, Nultsch W (eds) Environmental UV photobiology. Plenum Press, New York, pp 345–377Google Scholar
- Pattison DI, Davies MJ (2006) Actions of ultraviolet light on cellular structures. EXS 96:131-157Google Scholar
- Pérez JM et al. (2007) Bacterial toxicity of potassium tellurite: Unveiling an ancient enigma. PLoS ONE 2:e211Google Scholar
- Rünger TM, Farahvash B, Hatvani Z, Rees A (2012) Comparison of DNA damage responses following equimutagenic doses of UVA and UVB: a less effective cell cycle arrest with UVA may render UVA-induced pyrimidine dimers more mutagenic than UVB-induced ones. Photoch Photobio Sci 11:207–215CrossRefGoogle Scholar
- Smith DC, Azam F (1992) A simple, economical method for measuring bacterial protein synthesis rates in seawater using tritiated-leucine. Mar Microb Food Webs 6:107–114Google Scholar