UC San Diego

Biosilicification is an area of growing interest in marine biology, nanotechnology, and nanoscience. The process is ubiquitous in nature, with diverse species displaying siliceous structures. This comes as small wonder when one considers the immensity of silicon available to biogeochemical processes. No where is the process of silicification so highly specialized as in the production of cell walls by diatoms. Ongoing research in electron microscopy to follow the processes of silicification and current efforts to sequence genomes of marine diatoms and produce genetic transformation systems in some model species are unlocking the secrets of biosilicification. Already, biomimetic chemistry has enabled the mimicry of the silicification processes of diatoms in vitro. Surely, further understanding of the proteins, metabolic processes, and cellular structures tied to biosilicification in diatoms will lead to new frontiers in science and technology. In order to communicate pertinent information regarding aspects of diatom cell wall morphogenesis and biosilicification, a general introduction to diatom structure and cell wall formation will be supplied (Chapter I); including an introduction to the two species used in this study. In this work, efforts are made to study the process of biosilicification in naked protoplasts of the marine apochlorotic chemoheterotrophic species Nitzschia alba as they regenerate valves using microscopy methods for observation (Chapter II). Simultaneously, new vectors are generated for future studies in transformation of both N. alba, and the marine centric photoautotrophic diatom Thalassiosira pseudonana (Chapter III)