Physics Approaches to Studying the Biology of C. elegans
Caitlin Bell, Vassar College ’15, Ramy Abbady, Vassar College ’16, Brian Deer, Vassar College ’15, Elias Kim, Vassar College ’16 and Profs. Kathleen M. Raley-Susman and Jenny Magnes
Biophysics is a rapidly growing interdisciplinary science. In our collaboration, we used physical science methods to study the behavior of the microscopic soil dwelling nematode C. elegans. While traditional microscopic methods limit C. elegans to a two-dimensional environment, our methods replicate the nematode’s natural three-dimensional environment without a microscope. We used optical approaches with continuous wave lasers. One method we used was shadow imaging. In this process, we dropped worms into water-filled cuvettes that had each half (top and bottom) illuminated by an expanded laser beam. We then captured videos of the nematodes falling through the cuvette to study its vertical motion. Another method used a normal-sized laser beam to create diffraction around the worm, from which we calculated its swimming frequency. We also used diffraction to study crowded worms in a cuvette, for which we visually examined changes in the diffraction patterns over longer periods of time. While we show that single-worm diffraction is to be a reliable method for studying biological characteristics of C. elegans, studying multiple worms using these methods will require some adjustments. Optical measurement techniques like shadow imaging and diffraction dynamics will be very useful in the study of very small organisms.