Elizabeth Jones – Runner Up on 3-Minute Thesis: Stingrays and Sharks on Steroids

At the University of Southern Mississippi, under the fine tutelage of professor—and AFS memberDr. Andrew Evans, Elizabeth Jones was the runner up for her 3-minute thesis: Stingrays and Sharks on Steroids.

When you think of the effects of steroid hormones, you probably imagine a muscle bound body builder, but steroids cause a broad range of physiological processes beyond just building muscle. Two of these processes are energy mobilization, or release of stored glucose, and hydromineral balance, which includes things like regulation of blood pressure and salt. Sometimes these processes occur alone, and sometimes, they occur together; for example, when you are stressed, your body secretes steroids that release glucose stores for energy, and it also secretes steroids that increase blood pressure, which helps to rapidly deliver that glucose to your muscles. Usually, separate steroids control energy metabolism and hydromineral balance, as you see here. However, sharks, skates, and stingrays – what we call the elasmobranch fishes – have a single, novel steroid called 1α-B, which controls both of these functions. This presents us with an interesting question; does this mean that every time 1α-B is secreted, glucose is released AND blood salt concentration increased? That is exactly what my proposed research will examine. Specifically I will investigate mechanisms regulating the actions of 1α-B in elasmobranchs, and identify factors that determine when it acts in energy metabolism or hydromineral balance. Steroid hormones work by passing through cell membranes and attaching to DNA where they act to turn genes on or off. What I plan to do is to expose tissues from stingrays to 1α-B, then identify the genes that are turned on or off. This analysis of the genetic actions of 1α-B will help us understand how and when this steroid performs its different functions. So, why is this research important? Energy metabolism and hydromineral balance are involved in stress and movement between water bodies with different salt concentrations, or salinities. Both of these are phenomena that elasmobranchs deal with normally, but the frequency of these challenges has been increased by human activity. Sharks and rays are regularly caught as by-catch where they are exposed the stress of capture and handling. Coastal elasmobranchs often encounter rapid human-induced changes in salinity caused by actions such a spillway management during flooding. Elasmobranchs are ecologically important species that are critical to maintaining balance in marine food webs, yet a quarter of them have been listed as endangered species. So the reason this research is important it that it will lend insight into how elasmobranchs respond to the physiological challenges brought about by human activity will inform efforts to manage and conserve these ecologically important organisms. • 3MT slide • See the video here