Effect of Ionizing Radiation on Volvox carteri

Emma Mueller, St. Joseph's Academy, Saint Louis, MO, United States
In the 1940s Mallinckrodt Chemical Works was involved in the development of the first atomic bomb. They shipped nuclear waste to St. Louis County and did not dispose of it properly. The unattended waste seeped into groundwater and construction in the late 1900s sent radioactive material into the air. Thus, North St. Louis County residents have been exposed to ionizing radiation for many years. People ingested radioactive materials in food, inhaled particles from the air, or were exposed to radiation from contact with the water in nearby rivers, like Coldwater Creek. Today, the community struggles with diseases caused by ionizing radiation exposure. For example, many residents have cancer because radiation can cause DNA mutations. This experiment will investigate how ionizing radiation, in the form of ultraviolet light, will affect Volvox carteri, a form of green algae. A mutagenesis will be performed on a wild-type volvox strain with the lab name, Eve. V. carteri will serve as a good model organism because of its ability to transition between unicellular and multicellular forms. An additional positive attribute is that V. carteri has both germ, or reproductive, and somatic cells together. Ten cultures of V. carteri will be exposed to low levels of UV light for ten generations of offspring to observe phenotypic mutations. After each round of UV light exposure, the V. carteri cultures will be blocked from photoreactivation which will prevent enzymes from repairing the damage caused to the DNA and thus allow for accurate results. Observational data taken from all ten generations of offspring will be used to analyze the damaging effects of ionizing radiation. The results will potentially give insight into how radiation in Coldwater Creek led to a surplus of cancer patients in the North St. Louis area.