Relationship between the presence of wall mucilage and the cellular disruption method employed in Agaricus bisporus tertiary mycelium

Abstract

SUMMARYHyphal walls of Agaricus bisporus fruiting bodies were prepared by three different methods of breakage. The chemical and electron microscopic results obtained support the idea that most of the polysaceharide mucilage, loosely bound to the cell walls, remains attached to them when a mild method of cell disruption is used. INTRODUCTIONThe polysaccharide mucilage present in the wall of several Basidiomycetes [6,8,11] has not been well studied, mainly because of the variations encountered in its recovery. Although these differences may be due to its water solubility and its consequent removal during hyphal wall preparation, its existence as a true wall structural component. has not been questioned.The harsh methods of cell disruption employed to prepare walls up to now may be the reason why, besides the cellular breakage, materials loosely bound to the cell wall can be liberated and further excreted into the medium.In this paper we describe hyphal wall preparation of A. bisporus fruiting bodies using 3 different breakage procedures, and the consequent quantitative differences encountered in the polysaccharide wall mucilage recovery, correlated with an electron microscopic study of the isolated cell walls. MATERIALS AND METHODS OrganismFresh fruiting bodies of commercial A. bisporus standardized at stage of buttons [5] were used for the present study. Preparation of cell walls of fruiting body hyphaeA. bisporus fruiting bodies free of lamellae and spores were homogenized in distilled water with a blender in order to disaggregate hyphae. The hyphal suspensions (approx. 0.5 g fresh wt./ml) were submitted in the cold (4°C) to the action of one of the following: (1) Braun mechanical disintegrator (B. Braun, Mod MSK, Melsungen, F.R.G.) with glass beads (0.45-0.50 mm) for 1 min at full speed; (2) Ultrasonic disintegrator (MSE Mod MK2), for 1 min (12 microns); (3) Omni-mixer homogenizer, Ivan SorvaU (Mod 17106, Newtown, CT, U.S.A.) for 5 min at full speed.When the hyphal suspensions were completely disrupted, determined by phase-contrast microscopic examination, the walls were purified as previously described [10]. Isolation of the polysaccharide mucilagePurified walls of A. bisporus tertiary mycelium 0378-1097/86/$03.50

Differences in microfibrils in the walls of Agaricus bisporus secondary mycelium

“…la). Because of the surface nature of this material and its similarity with structures described previously [9] for Schizophyllum commune, this may represent a part of the mucilage loosely bound to the wall [5].…”

“…This surface is relatively amorphous showing some indication of an underlying coarse network of fibres. The polysaccharidic material attached to the wall surface is easily released into the surrounding medium [5] and shows, in this case, a filamentous appearance (Fig. la).…”

Enzymic activity of the mycoparasite Verticillium fungicola on Agaricus bisporus fruit body cell walls

“…Preparation of hyphal cell walls. A. bisporus fruit bodies, free of lamellae, were sliced and disrupted by the action of a Polytron homogenizer and the walls purified as described by Avellán et al . (1986).…”

News & Notes: Production, Purification, and Properties of an Endo-1,3-β-Glucanase from the Basidiomycete Agaricus bisporus

“…Fragments of commercial Agaricus bisporus fruiting bodies (strain H25) harvested at the button stage were cultivated on compost-agar (5% dehydrated compost) for isolating vegetative mycelium. On the other hand, cell walls of A. bisporus fruiting bodies H25 (free of lamellae and basidiospores) were prepared by the method of Avellán et al [1]. Agaricus bisporus vegetative mycelium was grown on Hanseler medium [9] modified by adding 0.1% (wt/vol) fructose plus 0.1% (wt/vol) A. bisporus cell walls as carbon source.…”