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Repair of UV-B induced DNA damage at different temperatures in the red algae Palmaria Palmata (Linnaeus)

Martins, R. (1998) Repair of UV-B induced DNA damage at different temperatures in the red algae Palmaria Palmata (Linnaeus). Master's Thesis / Essay, Biology.

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Due to an increasing ozone depletion, the amounts of UV-b reaching the Earth and the sea are also increasing. This is a cause of concern since the DNA molecules have a strong absorption within the UV-B range, and therefore, exposure to this type of radiation can lead to the formation of several photoproducts such as thvmine dimers and (6-4) photoproducts. For this reason, the aim of this project was to study the induction and repair efficiency of thymine dimers and (6-4) photoproducts in the red alga Pa/maria palmata, and also, the influence of temperature in these processes. In the present study, the alga Pa/maria palmata proved to be able to repair the two major photoproducts induced in the DNA by UV-B radiation thvmine dimers and (6-4) photoproducts. This plant eliminates more efficiently thymine dimers than (6-4) photoproducts in the presence of UV-A and PAR, which contradicts experiments previously done by van Vugt (1998). Also, it is evident that this isolate maintain its repair capacity at extreme temperatures. o and 25° C. The repair efficiency of the two studied photoproducts presented distinct patterns throughout the experiments; photorepair of thymine dimers is more efficient towards higher temperatures. especially at 25° C, while the (6-4) photoproducts were more efficiently eliminated at the optimal temperature, 12° C. More repair efficiency of both photoproducts was observed in the absence of UV-B, though some repair activity is possible in its presence. The induction of damage was shown to be temperature independent.

Item Type: Thesis (Master's Thesis / Essay)
Degree programme: Biology
Thesis type: Master's Thesis / Essay
Language: English
Date Deposited: 15 Feb 2018 07:44
Last Modified: 15 Feb 2018 07:44

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