Glycoconjugates and polysaccharides of fungal cell wall and activation of immune system

Abstract

Glycoproteins, glycosphingolipids and polysaccharides exposed at the most external layers of the wall are involved in several types of interactions of fungal cells with the exocellular environment. These molecules are fundamental building blocks of organisms, contributing to the structure, integrity, cell growth, differentiation and signaling. Several of them are immunologically active compounds with potential as regulators of pathogenesis and the immune response of the host. Some of these structures can be specifically recognized by antibodies from patients’ sera, suggesting that they can be also useful in the diagnosis of fungal infections.

Development of a Bioactive Food Additive for Controlling of Fungal Growth

“…The differences in the inhibitory activity of CGP/TCWDE against the tested fungi is probably related to variances in the composition of the cell wall of these microorganisms, which conferred different susceptibility to the hydrolytic action of the TCWDE (Silva et al, 2011). Moreover, the main constituents of the fungal cell wall -polysaccharides (chitin and α-and β-glucans), proteins, and lipids -may be differently distributed across the cell walls of A. fumigatus and Penicillium sp., (Hearn et al, 1998;Pinto et al, 2008), producing different hydrolysis susceptibility. TEM micrographs reinforced and evidenced the action of the CGP/TCWDE as growth inhibitor agent (Figure 4).…”

Targeting carbohydrates: a novel paradigm for fungal control

“…For example, in A. fumigatus the decorating polysaccharides are composed of galactomannan and β-(1,3)-(1,4)-glucan (absent in C. albicans), whereas C. albicans contains mainly β-1,6-glucan (absent in A. fumigatus) (Fontaine et al 2000;Aimanianda et al 2009b). In other words, branching of β-(1,3)-glucans in A. fumigatus results in increased numbers of acceptor sites for chitin, galactomannan and a linear β-(1,3)-(1,4)-glucan, substituting the β-(1,6)-glucan commonly expressed in other fungi (Pinto et al 2008). In budding yeast cells, a scar is left on the mother cell after separation of the bud, and at this site the components of the inner layers of the cell wall, such as chitin and β-(1,3)-glucan, can become exposed at the surface.…”

“…However, the major differences are due to their protein composition, which underscores the importance of cell wall proteins in pathogenesis (Pinto et al 2008).…”

“…Glucans can also covalently bind to cell wall proteins (CWP) (Pinto et al 2008). The major class of C. albicans CWPs are glycosylphosphatidylinositol (GPI)-anchor-dependent cell wall proteins (GPICWPs), which are attached through a GPI remnant to β-(1,3)-glucan or chitin by a highly branched β-(1,6)-glucan linker.…”

“…This is further illustrated by the observation that several fungal cell wall polymers are immunologically active compounds with great potential as regulators of pathogenesis and the immune response of the host. In addition, some of these molecules can be specifically recognized by antibodies from patients' sera, suggesting that they can also be useful in the diagnosis of fungal infections (Pinto et al 2008). Furthermore, coating of fungal cells with host antibodies has the potential to strongly influence the hostpathogen interaction by affecting antibody-mediated functions such as opsonin enhanced phagocytosis and blocking the binding activity of fungal adhesins to host ligands (López-Ribot et al 2004).…”