Two distinct classes of polyuronide from the cell walls of a dimorphic fungus, Mucor rouxii

Abstract

Polyuronides were extracted from purified yeast and mycelial walls of Mucor rouxii by sequential treatments with lithium chloride and potassium hydroxide and were fractionated by ion-exchange chromatography on DEAE-Sephadex. Two polymers (I and II) of different acidity were found in both wall types. Polymer I contained D-glucuronic acid, L-fucose, D-mannose, and much smaller amounts of D-galactose. Yeast and mycelial polymer I had similar uronic acid contents but differed in their neutral sugar compositions and molecular weights. Polymer II from both cell types contained largely D-glucuronic acid and had similar molecular weights. On partial acid hydrolysis, both polymers I and II gave rise to insoluble glucuronans which appeared to be homopolymeric. One-third of the total uronosyl residues of polymer I, and almost all of the uronosyl residues of polymer II, were present in homopolymeric segments. However, homopolymers derived from polymers I and II may not be identical.

Mucor dimorphism.

“…Table 1 displays the comparative composition of cell walls from Mucor yeasts, hyphae, sporangiophores, and sporangiospores. The main structural components of both yeast and hyphal walls are chitin and chitosan fibrils embedded within a matrix of the polyuronides mucoran and mucoric acid, glycoproteins, and glycopeptides (26,27,57,60). The contribution of the fibrillar components to the total mass of the cell wall is not much different in yeasts and hyphae.…”

“…Whereas Bartnicki-Garcia and Ruiz-Herrera have looked to the chitin-chitosan microfibrillar skeleton of the Mucor cell wall for the key to explaining dimorphism, Dow, Villa, and colleagues have focused on the polyuronide matrix components of the wall in search of correlates with morphogenesis (57,60,61). It is an entirely reasonable proposition that the properties of the mortar may be as important as those of the brick in defining the potential architecture of an edifice.…”

“…It is an entirely reasonable proposition that the properties of the mortar may be as important as those of the brick in defining the potential architecture of an edifice. Both Mucor yeasts and hyphae contain readily extractable acidic matrix heteropolymers (mucorans) which have D-glucuronic acid as the main sugar component and lesser amounts of L-fucose, D-galactose, and D-mannose (57,60). Nonextractable poly-D-glucuronic acid (mucoric acid) is also an important component of the matrix in both Mucor yeasts and hyphae (57,60).…”

Use of Anionic Polysaccharides in the Development of 3D Bioprinting Technology

“…It was designed as mucoran. The other polymer contained large amounts of D-glucuronic acid and was designed as mucoric or fungal β-(1,4) glucuronan acid [44]. Previous studies have also revealed the presence of β-(1,4)-D-polyglucuronic acid in the cell walls of several green algae [45,46].…”

“…It was designed as mucoran. The other polymer contained large amounts of d-glucuronic acid and was designed as mucoric or fungal β-(1,4) glucuronan acid [44].…”