N-Glycosylation in gastropods

Research project P 13928 N-Glycosylation in gastropods Erika STAUDACHER 11.10.1999 Although some gastropods (phylum mollusca) are used as foodstuff and others are a remarkable pest in agriculture or serve as intermediate hosts for parasites, only little is known about their glycosylation potentials. Therefore this project will elucidate the N-glycosylation patterns of four different snails (water- and land-living animals, with and without shell) and the glycosyltranferases involved in vivo in the biosynthesis of these oligosaccharides will be purified and characterised. With the knowledge on the glycosylation abilities of gastropoda it may be possible to establish a new cell culture system, to uncover new means for pest control for some species, or to identify already known allergic carbohydrate-epitopes. Furthermore specific exoglycosidases will be purified from the snails in a preparative scale, which may be potential tools for glycan analysis.

The snails Arion lusitanicus, Limax maximus, Cepaea hortensis, Helix pomatia, Planorbarius corneus, and Limnea stagnalis were investigated for their N-glycosylation capabilities. The N-glycans from adults (skin and viscera preparations) and eggs were analysed for their sugar compositions and linkages. The gastropods show an enormous potential in generating a large set of structural glycosylation elements of eukaryotic N-glycosylation combining structural features from mammals, plants, insects, nematodes and trematodes. This is the first known complete system where it is possible to investigate the regulation of N-glycan modification in its fullest variety. An understanding of this complex system, i.e. why a distinct structure occurs on a certain protein, will improve our knowledge on the rules of glycan modification and help to optimise the production of recombinant glycoproteins. The detailed knowledge of the very complex glycosylation system of the snails will be a valuable tool to understand the rules of glycosylation in other organisms, which are used for the recombinant production of correct glycosylated pharmaceuticals. In addition, the snail system is the first opportunity to produce in a safe way structures analogous to pathogenic nematodes in order to use them to stimulate the immune system. The identification of snail-typical glycosylated glycoproteins, which have specific functions for survival or reproduction and do not occur in other organisms, will make it possible to identify targets for pest control. The inhibition of mammalian-untypical enzymes would be a convenient way to reduce the population of these animals without high amounts of chemical pesticides.