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Effects of Ozone
Depletion on DNA Photoproduct Yields at Palmer Station, Antarctica
Mitchell, David1,
Meador, Jarah 1 and Jeffrey, Wade2
The University of Texas MD Anderson Cancer Center, Science Park/Research
Division, Smithville, Texas 789571
Center for Environmental Diagnostics and Bioremediation, University of
West Florida, Pensacola, Florida 325142
Abstract-
There is now strong evidence that ultraviolet radiation (UVR) is increasing
over certain locations due to stratospheric deozonation. This is particularly
evident over Antarctica and the Southern Ocean where ozone levels have
declined as much as 74% compared to pre-ozone hole levels. The spectrum
of DNA photodamage induced by sunlight is wavelength dependent with
direct damage, such as pyrimidine dimers, resulting from UV-B radiation
and indirect damage, such as 8-hydroxydeoxyguanosine (8oxodG), resulting
from UV-A. Because ozone absorbs UVB, ozone depletion results in an
increased proportion of wavelengths causing direct DNA damage. Radioimmunoassays
were used to quantify pyrimidine dimers, (6-4) photoproducts, and 8-oxodG
in purified DNA dosimeters and size-fractionated plankton harvested
daily at Palmer Station, Antarctica during the austral Spring and Summer
of 1999/2000. As expected, yields of direct damage in DNA correlated
with UVB exposure and the ratio of direct to indirect damage correlated
with ozone depletion. This work was supported by National Science Foundation
grant OPP-9801785.
Keywords: 8-oxodeoxyguanosine,
cyclobutane dimer, deozonation , plankton
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