Graduation Year


Document Type

Open Access Senior Thesis

Degree Name

Bachelor of Arts


W.M. Keck Science Department

Second Department


Reader 1

Zhaohua Irene Tang

Reader 2

Mary Hatcher-Skeers

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Rights Information

© Amy V. Tran


Butylated Hydroxyanisole, BHA, and Butylated Hydroxytoluene, BHT, are commonly used as preservatives for our food as well as additives in many products such as cosmetics, petroleum, and medicine. Although their use has been approved by the Food and Drug Administration (FDA), there have been controversies and debates on whether these phenol derivatives or antioxidants are safe to use. Their accumulative toxicology and side effects need to be thoroughly investigated as we continue to consume them on a daily basis. Data obtained by genomic analysis in Tang lab suggested the involvement of DNA damage checkpoint/repair pathways in the response network to these phenol stress factors. The aims of this thesis are to examine the morphological changes and potential DNA damage induced by exposing cells to BHA and BHT using fission yeast Schizosaccharomyces pombe as a model organism. Fluorescence microscopy was used to assess DNA double-strain breaks (DSBs) by monitoring the nuclear foci formation of Rad22, a DNA repair protein, in the presence of BHA and BHT. Changes in cell morphology were also studied under microscope. Preliminary data showed that cells treated with BHA and BHT exhibited morphological changes. In addition, for the first time in S. pombe cells, Rad22 foci in the nucleus of BHA and BHT treated cells were observed. Further investigation is needed to optimal the experimental condition to continue the study. These results will not only help us to better understand the effect of these phenol derivatives in the cells, but can also establish an experimental system for future studies on the interaction of the cells with stress factors and therapeutic drugs for human-related diseases such as cancer.