Comet assay på Saccharomyces cerevisiae

The purpose of this project is to clarify whether Saccaromyces cerevisiae (bakers yeast) can be used as a model for Mytilus edulis (blue mussel) in association with investigation of DNA damage. S. cerevisiae was exposed to the herbicide 2,4-Dichlorophenoxyacetic acid (2,4-D) in order to examine this. For the purpose of measuring the genotoxic damages the Single Cell Gel Electrophoresis (SCGE) method was used, also known as comet assay. The results were compared with results from a similar experiment that was carried out with M. edulis. The method was modified by adding the enzyme glucolase (contains s-Glucuronidase and s-Glucuronide Sulfatase) in order to break down the cell wall of S. cerevisiae. This was done because the cell wall prevents the S. cerevisiae DNA from migrating in the electric field during electrophoresis. The experimental results were reviewed with the software Comet assay III by Perspective Instruments. The following units describe the severity of the DNA damage: Tail Moment, Tail Length and Tail Intensity. The results did not show any significant comet tails. It is reasonable to conclude that this was due to glucolase which was not capable of disintegrating the cell wall. That is why damage on the DNA could not be observed as comet tails. A clearly defined clarification, if yeast can serve as a model for the blue mussel, has therefore not been possible.