DNA, comets and shaky hands

Hi everyone!

My name is Piia Karhu and I am a first-year student in The Master’s Programme in Human Nutrition and Food-Related Behaviour at the University of Helsinki. I received a HiLIFE scholarship for the summer 2020 to work in a research project of my interest. I completed my research internship at the Viikki Molecular Nutrition group. The group studies the molecular mechanisms by which diets, foods and diet-derived compounds mediate their effects on health and prevention of non-communicable diseases. I was very happy to join this group as molecular nutrition is a very fascinating field of science. Here you can read more about Viikki Molecular Nutrition group.

During my summer, I was privileged to take part in the study that examines the impact of dietary habits on faecal water genotoxicity.  In the study, colonial epithelial cells were exposed to feacal water. Feacal water was extracted from stool samples collected during dietary intervention with healthy volunteers and the DNA damage created by the faecal water was examined. Purpose was to study whether there are differences in DNA damage of the cells when exposed to fecal water from volunteers that followed either plant protein diet, animal protein diet or diet that contains half plant protein and half animal protein. We measured the DNA damage using single-cell gel electrophoresis known as Comet assay. It is a commonly used and straightforward method for measuring DNA strand breaks in cells. The term “comet” refers to the leaked-out DNA of the cell as it often resembles a comet. The more intensive the comet tail is relative to the head of the cell, the more the cell is damaged.

microscope image of green cell comets
Here is an example picture of the comets

I had very interesting and mind opening summer job as I have never worked in this kind of project before. I acquired valuable experience working in the lab, especially in the cell lab and learned how to culture and handle cells. Working in a cell lab was a very nice experience even though it took a while before my hands stopped shaking! During my summer I gained a lot of practical experience, which will boost my confidence working as a researcher in the future.

I want to thank my supervisor Anne-Maria Pajari for this opportunity to work in her research group and Hana Slabá for excellent guidance during the summer. Also, I am deeply grateful to HiLIFE for supporting me, this was a very valuable experience!