Surface Coat

Synonyms

Glycocalyx (Apicomplexa/Surface Coat).

General Information

Surface coats are present both in protozoan and in helminthic endoparasites. In general, the plasma membrane of cells is strikingly asymmetric, its outer and inner layers are clearly delineated, and the polypeptides on each surface are distinct. Glycolipids, glycoproteins, and glycosphingolipids are present only on the external surface. The peripheral layer is rich in carbohydrate and is called the glycocalyx, or surface coat. The thickness of this layer varies with the species and with the developmental stage of the organism (Fig. 1, Pellicle, Fig. 3A). Not only is the surface coat composed of glycoproteins and glycolipids, but various glycoproteins and proteoglycans (acid mucopolysaccharides) may also be adsorbed to it (for more details see Apicomplexa/Surface Coat). The surface coat may be a rather delicate coating, a mass of delicate filaments, or a thick mat, and it comprises 10 % of the cell protein. Whatever...