The β-glycan polysaccharide family includes cellulose, the abundant and ubiquitous plant cell wall structural polymer, invertebrate and fungal chitin, yeast cell wall glucans, hyaluronan and other extracellular matrix polymers of vertebrates, as well as numerous extracellular bacterial polysaccharides of commercial and agronomic significance. The biogenesis of these polymers is receiving increasing attention as genes encoding their synthases are discovered. Though still rudimentary our basic understanding of the biochemistry of the synthetic processes and their control is growing rapidly. This review offers an overview, from a comparative viewpoint, of our current knowledge of enzymic events in β-glycan synthesis.
Mucins are highly glycosylated proteins present in both soluble and membrane bound forms, the latter being a part of the glycocalyx covering on cell surfaces. Both forms of mucins are the major components in the mucus gel on epithelial surfaces, which plays an important role in the aqueous/epithelium interface. Since the mucus layer masks the very hydrophobic surface of the lipid layer on the epithelium, the epithelium appears as a highly wettable surface. Owing to this surface property and the steric effect of the carbohydrate side-chains, non-specific adsorption of plasma proteins and non-specific adhesion of cells to the epithelium are both suppressed. We mimicked the glycocalyx structure on the surface of artificial material by coating mucin to develop non-adhesive and better biocompatible materials. A monolayer of mucin, which was observed on the surface of hydrophobic materials, induced a significant change in surface hydrophobicity to give highly wettable surfaces for hydrophobic materials. The protein adsorption and cell/bacterial adhesion on these biomimetic surfaces by mucin coating was greatly reduced.
Glycolipids, particularly glyceroglycolipids, are major membrane lipids in photosynthetic organisms. In higher plant cells, they are accumulated in chloroplasts, the site of photosynthesis. Glycolipids account for 90% of the chloroplast membrane lipid. In spite of their abundance in chloroplast, little was known about the biosynthesis and function of these glycolipids. In the past three years, significant progress has been made in this important field. Here we describe the biosynthetic machinery for glyceroglycolipids in photosynthetic organisms and the evolutionary origin of the glycolipids.
The TRANSFAC system comprises a number of originally independent databases on gene regulation. Associated with these data resources are several programs enabling the user to apply these data contents onto user-specific problems. A short description of the individual database modules and the associated programs as well as an outlook to future perspectives is given.