N-glycan epitopes in bivalve self/non-self recognition

Great advances have been made in recent years as regards genomic comparisons between organisms due to the large number of genome sequencing projects. In part these studies have altered our view of the phylogeny of organisms. However, the comparison of protein-linked carbohydrates, e.g., N-linked glycans, between organisms continues to lag behind due to the complicated nature of glycan analyses. On the other hand, glycans in their various types have key roles in fertilisation, development, morphogenesis and host-pathogen interactions as they cover the surfaces of all cells and so are involved in a wide range of cell-cell and self/non-self interactions In this project, it is proposed to focus on the N-linked glycans of selected bivalves, a group of predominantly marine organisms including oysters and clams – as a human food source, they have economic importance; on the other hand, as filter feeders they are of high ecological relevance. Furthermore, they harbour human pathogens, but are also susceptible to their own pathogens; invasive species (such as the pacific oyster, Crassostrea gigas) can be more resistant to these than the native bivalves. Glycans of bivalves representing different families and habitats (including the pacific oyster and clams) will be examined. The fine detail of the N-glycans of these organisms will be assessed by mass spectrometric and other analyses. Correlations between the loss or gain of carbohydrate epitopes will be made with genomic and lectin binding data; for the latter, a tailor-made array of glycans from different species and tissues will be developed and promises to drive forward our functional knowledge about the self/non-self recognition between lectins and glycans. The result of this study will be a deeper understanding of a group of key post-translational modifications in a class of organisms of environmental and economic importance and their contribution to self vs. non-self recognition as models for innate immunity.