(full paper is archived in the Miller Library)
Title: Photoprotective role of the egg follicle cells in the sea squirt Ascidia ceratodes
Student Author(s): Unger, Annie V.
Faculty Advisor(s): Epel, David
Location: Final Papers Biology 175H
Date: June 1997
Abstract: A photoprotective role has been ascribed to the ultraviolet radiation-absorbing mycosporine-like amino acids (MAAs) present in the follicle cells surrounding eggs of the tunicate Ascidia ceratodes. Studies were performed using natural sunlight and a variety of wavelength filters to expose intact Ascidia eggs and eggs in which the MAA-containing follicle cells had been removed to various types of ultraviolet radiation. The kinetics of development were examined to ascertain whether the follicle cells were acting to protect the eggs from UV damage. This series of studies demonstrated that at ambient solar radiation levels there are no observable differences in rates of early development between Ascidia embryos where follicle cells were removed and embryos with an intact follicle cell layer. This study suggests that the tunicate embryo has a variety of defenses against UV damage, and the defensive role played by mycosporine-like amino acids may not be of primary importance.