The cell walls of Agaricus bisporus and Agaricus campestris fruiting body hyphae

Abstract

The hyphal walls of Agaricus bisporus and Agaricus campestris fruiting bodies were isolated and purified. Quantitative analyses revealed that these walls consisted mainly of carbohydrates (78.3–79.2%), lipids (9.9–10.1%), and proteins (8.7–10.2%). The major components of carbohydrate polymers were glucose, N-acetylglucosamine, and glucosamine. In addition, small quantities of galactose and mannose have been found.N-Acetylglucosamine and glucosamine were identified chemically and enzymatically, and also by infrared spectrum and X-ray diffraction analyses, as chitin and chitosan. Neutral polysaccharides include an alkali-soluble glucan with α(1–3) linkages and a β(1–3)- and β(1–6)-linked glucan.The lipid fractions in both hyphal walls contained precursors of melanin, this pigment being largely represented in Agaricus spore walls. Amino acids analyses indicate that structural wall proteins were very similar in both organisms.In electron micrographs of ultrathin sections of hyphae no distinct layering was apparent in contrast with spore walls of the same organism, which show two wide well-defined layers.