Title

DNA Repair of Daphnia magna in response to Ultraviolet Radiation

Presenter Information

Amanda Tompkins
Amanda Smith

Document Type

Oral Presentation

Location

SURC Ballroom A

Start Date

17-5-2012

End Date

17-5-2012

Abstract

Ultraviolet radiation (UVR) is a necessity for life. However, reduction in stratospheric ozone has resulted in increased levels of UVR at the Earth’s surface. This radiation causes potentially lethal DNA damage, including formation of cyclobutane pyramidine dimers. Organisms have evolved a number of enzymes to repair such damage, some of which are powered by visible light. Here we investigated UVB-induced DNA damage and subsequent DNA repair in Daphnia magna, a planktonic crustacean and model organism for toxicology. We wanted to find out if Daphnia manga sustain DNA damage at ecologically relevant doses of UVR, and whether or not they can repair this damage. We exposed pregnant D. magna to UVR and used a comet assay to assess DNA damage of embryos either immediately after exposure or after a subsequent 24-hour repair period. To perform the comet assay, we extracted early stage embryos, suspended the cells in agarose, lysed them, and pulled the damaged DNA out of the nuclei via electrophoresis. We used a florescent microscope to take pictures of the DNA and quantified levels of DNA damage using CometScore Software. Comparison with appropriate controls revealed highly significant damage due to UVR exposure and a marginally significant signature of DNA repair. Future research will focus on quantifying population-level variation in damage and on identifying the mechanism of repair.

Poster Number

11

Faculty Mentor(s)

Alison Scoville

Additional Mentoring Department

Biological Sciences

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May 17th, 8:30 AM May 17th, 11:00 AM

DNA Repair of Daphnia magna in response to Ultraviolet Radiation

SURC Ballroom A

Ultraviolet radiation (UVR) is a necessity for life. However, reduction in stratospheric ozone has resulted in increased levels of UVR at the Earth’s surface. This radiation causes potentially lethal DNA damage, including formation of cyclobutane pyramidine dimers. Organisms have evolved a number of enzymes to repair such damage, some of which are powered by visible light. Here we investigated UVB-induced DNA damage and subsequent DNA repair in Daphnia magna, a planktonic crustacean and model organism for toxicology. We wanted to find out if Daphnia manga sustain DNA damage at ecologically relevant doses of UVR, and whether or not they can repair this damage. We exposed pregnant D. magna to UVR and used a comet assay to assess DNA damage of embryos either immediately after exposure or after a subsequent 24-hour repair period. To perform the comet assay, we extracted early stage embryos, suspended the cells in agarose, lysed them, and pulled the damaged DNA out of the nuclei via electrophoresis. We used a florescent microscope to take pictures of the DNA and quantified levels of DNA damage using CometScore Software. Comparison with appropriate controls revealed highly significant damage due to UVR exposure and a marginally significant signature of DNA repair. Future research will focus on quantifying population-level variation in damage and on identifying the mechanism of repair.