Differences in microfibrils in the walls of Agaricus bisporus secondary mycelium

Thick fibres mainly located in longitudinal and parallel arrays were observed on the outer surface of vegetative mycelial walls of Agaricus bisporus treated to remove the polysaccharide mucilage. When thick fibres were removed from the cell wall, by alkali treatment, thin fibres with predominantly transverse orientation were observed. The former have been identified to be composed of α-glucan and the latter of chitin. Both different types of fibres constitute the skeletal components of the wall in which matrix materials are embedded.