Study of Diseases and the Immune System of Bivalves Using Molecular Biology and Genomics

Environmental chemico-physical factors, pathogens, and biological interactions constantly affect organism physiology and behavior Invertebrates, including bivalve mollusks do not possess acquired immunity. Their defense mechanisms rely oil all innate, non-adaptive immune system employing circulating cells and a large variety of molecular effectors. The mechanisms underlying host defense depend oil the presence of functional proteins in appropriate quantities, within a crucial time window. These proteins arc, encoded by genes whose transcription is tightly coordinated by complex programs of gene expression. Currently, available advanced techniques allow the evaluation of this gene expression, expanding our understanding of the behavior and function of cells and tissues under varying conditions. In particular DNA microarray technology enables measurement of a large predetermined set of known genes or sequences. Expressed sequence tag sequencing from redundant, normalized, subtractive hybridization libraries is a robust method for sampling the protein encoding genes that are expressed within a tissue. The elimination of microorganisms by defense cells is a dynamic process that involves integrating synthesis of granule proteins during differentiation, migration onto sites of infection, phagocytosis and killing of microorganisms, modulation of their effector cells, and finally apoptosis. Understanding how this complex biological process is regulated call best be addressed using a systems biology approach to the stud), of organisms and populations in order to more effectively decipher the continuous challenge between two genomes, i.e., evolving host-pathogen interactions.