The fungal cell wall: Modern concepts of its composition and biological function

This review deals with the cell wall (CW), a poorly known surface structure of the cell of mycelial fungi. Data are presented concerning (i) isolation techniques and purity control methods securing the absence of the cytoplasm content in the CW fraction and (ii) the chemical composition of the CW. The structural (backbone) and intrastructural components of the CW, such as aminopolysaccharides, alpha- and beta-glucans, proteins, lipids, uronic acids, hydrophobins, sporopollenin, and melanins, are discussed in detail. Special attention is given to chitin and its novel function in terms of protecting the cells from stress as well as to the differences of this fungal aminopolysaccharide from the chitin of algae and Arthropoda. The apical growth of hyphae and the involvement of special microvesicles in morphogenesis of a fungal cell are discussed. Data on the enzymes involved in CW synthesis and lysis are presented. In conclusion, the functional role of the fungal CW is discussed in juxtaposition to the surface structures of higher eukaryotes.