Title of article :
Molecular response to climate change: temperature dependence of UVinduced DNA damage and repair in the freshwater crustacean Daphnia pulicaria
Author/Authors :
Mitchell، David L. نويسنده , , J. MacFadyen، Emily نويسنده , , E. Williamson، Craig نويسنده , , Gabriella Grad، نويسنده , , Megan Lowery، نويسنده , , H. Jeffrey، Wade نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2004
Pages :
-407
From page :
408
To page :
0
Abstract :
In temperate lakes, asynchronous cycles in surface water temperatures and incident ultraviolet (UV) radiation expose aquatic organisms to damaging UV radiation at different temperatures. The enzyme systems that repair UVinduced DNA damage are temperature dependent, and thus potentially less effective at repairing DNA damage at lower temperatures. This hypothesis was tested by examining the levels of UV-induced DNA damage in the freshwater crustacean Daphnia pulicaria in the presence and absence of longerwavelength photoreactivating radiation (PRR) that induces photoenzymatic repair (PER) of DNA damage. By exposing both live and dead (freeze-killed) Daphnia as well as raw DNA to UV-B in the presence and absence of PRR, we were able to estimate the relative importance and temperature dependence of PER (light repair), nucleotide excision repair (NER, dark repair), and photoprotection (PP). Total DNA damage increased with increasing temperature. However, the even greater increase in DNA repair rates at higher temperatures led net DNA damage (total DNA damage minus repair) to be greater at lower temperatures. Photoprotection accounted for a much greater proportion of the reduction in DNA damage than did repair. Experiments that looked at survival rates following UV exposure demonstrated that PER increased survival rates. The important implication is that aquatic organisms that depend heavily on DNA repair processes may be less able to survive high UV exposure in low temperature environments. Photoprotection may be more effective under the low temperature, high UV conditions such as are found in early spring or at high elevations.
Keywords :
photoreactivation , ultraviolet radiation , temperature , zooplankton , DNA repair , DNA damage
Journal title :
GLOBAL CHANGE BIOLOGY
Serial Year :
2004
Journal title :
GLOBAL CHANGE BIOLOGY
Record number :
99406
Link To Document :
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