CHAPTER 1. INTRODUCTION time in Gaya's lab, he has provided guidance and support, and his general enthusiasm for science is contagious and fosters a stimulating learning environment which has helped me developed as an independent scientist. I would also like to give a special thanks to Dr. Daisy Leung. Through the help and mentorship of both Gaya and Daisy, I have grown as a student, a scientists, a colleague, and a person, and will forever be grateful for the guidance they have given me. I would also like to thank all of the member of the Amarasinghe lab whom I have had the privilege to work with. All of these individuals have invested their time to help assist me with experiments and training, and have always been available for me to exchange thoughts and ideas with. Additionally, they have been a source of support and encouragement, making each day in lab a new and enjoyable experience. I also thank my committee members, Dr. Kristen Johansen, Dr. Drena Dobbs, Dr. Michael Shogren-Knaak, and Dr. Scott Nelson, for their guidance, support, suggestions, and encouragement, as well as both the Iowa State University and Washington University communities for their rich learning environments. xiv Lastly, I would like to thank my family and friends for providing an invaluable support network. Through their continuous love and support, I had the courage to follow my dreams.