Testing for Ultraviolet Toxicity Using Fungi

Abstract

A relevant subject in biochemistry is the study of diverse effects of ultraviolet (UV) radiation on organisms. While short exposure of culture cells to UV radiation may produce point mutations, deletions, or rearrangements, long exposure may lead to cellular death. In this article, we describe a laboratory project quantifying the effects of UV radiation on a suspension of living cells. This laboratory experiment was designed for undergraduate students in biochemistry. The experiment was carried out employing different fungi strains, changing the dosage of radiation, the distance to the UV source, and the exposure period to the UV radiation. The quantity of viable spores was calculated and the dose–response curves were drawn. Students were able to prove that 100% of mortality was achieved with the longest time of exposure. The percent of cell survival decreased when the distance to the UV source was shorter. After the experimental manipulation, groups of students shared results with one another, and a final report with comparison of the results was to be handed in by each one. Thus, this experiment engaged the students in a mini-research experience. The pedagogic aim of this laboratory design is to familiarize students with chemical UV radiation reactions responsible for cellular and molecular damage.