The International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.
This award will support a three-month research fellowship by Dr. Jarah A. Meador to work with Drs. Theirry Douki and Jean Cadet at Centre d'Energie Atomique de Grenobe, Laboratoire des Lesions de Acides Nucleiques (UMR CNRS) in Grenoble, France, and Dr. Fabien Joux at the Universite Paris VI in Banyuls sur-Mer, France.
The focus of this research will be to determine if temperature and nutrient limitations are factors that influence UV induced DNA damage and repair in marine bacteria. The global environment is changing and substantial shifts in temperature, rainfall, cloud cover, ultraviolet radiation (UVR) and nutrient loading are all predicted as a result of anthropogenic activity. Although the actual and potential effects of changes in single environmental variables are being studied, the interactive effects of multiple stressors have received little attention. It is possible that these factors interact with each other in a synergistic manner. Phytoplankton and bacterioplankton comprise the base of oceanic foodwebs, and the molecular effects of UVR on these communities may have far reaching impacts on marine ecosystems. Although UVR responses of phytoplankton have been extensively studied, the responses of bacterioplankton to UVR are comparatively less well understood. Elucidating these responses to intense UVR is important for understanding the influence of UVR on bacterial diversity and photoadaptation processes and ultimately on the impact that UVR may have on other ecological processes.
Because DNA readily absorbs solar UVR within the UV-B region, much of the biological activity of sunlight is dependent on the photochemistry of this molecule. UV-screening and repair mechanisms may exist to prevent or attenuate UV-B mediated damage to DNA. The net biological effect of UVR is dependent upon the balance between the rate of damage induction and the rate at which that damage is repaired. It is important to evaluate UVR sensitivity in relation to species-specific differences in induction of DNA damage, DNA repair capacity, survival, and population growth. A complete distribution of the UVR induced photoproducts within cellular DNA will be obtained from specific chromatographic analyses following DNA hydrolysis, using a high performance liquid chromatographic-tandem mass spectrometry method (HPLC-MS/MS).
