Shigeru Deguchi (R&D Center for Marine Biosciences)
ABSTRACT
Early evolution of metazoan development happened in the sea, dating back to pre-cambrian times. A phenomenon called the "Cambrian diversification" or "Cambrian explosion" comprises the discovery of about 543 million years old fossils. Such fossils of marine origin indicate that the big variety of modern animal body plans must have diversified within a very limited time span. Mollusc shells are good model systems to explore some basic requirements in terms of the biological toolkit. Apart from that, these animals developed the potential to encode extracellular "self-organizing" materials with hierarchical textures, nano- to micron sized. Such mineralized composite materials not only superiorly mechanically protected the soft body of the animal from predators, but also efficiently ensured "survival" of the shell material over millions of years in the fossil record. Direct reconstruction of molecular and cellular key events of that time period, long after the soft body parts including ancient DNA have disappeared, seems practically impossible. Based on several lines of evidences, some light will be shed on ancient mechanistic relationships between materials science and biology, by investigating the case of a chitin polymerizing, transmembrane motor enzyme of marine bivalve molluscs.
