Mycelium

About: Mycelium is a research topic. Over the lifetime, 8923 publications have been published within this topic receiving 170993 citations.

Carbohydrate metabolism in Agaricus bisporus (Lange) Sing: changes in soluble carbohydrates during growth of mycelium and sporophore.

Abstract: SUMMARY: Changes in the ethanol-soluble carbohydrate content of Agaricus bisporus mycelium and sporophores grown on semi-defined media and commercial compost were studied. The accumulation of mannitol in the sporophore during its growth was not accompanied by an increase in mycelial mannitol. The other major soluble carbohydrate of the sporophore, trehalose, decreased throughout the growth of the sporophore; a parallel decrease was observed in the mycelium. The main accumulation of mannitol was in the pileus and stipe of the sporophore and was accompanied by a decrease in the soluble protein content of these tissues. Before fruiting, glucose and sucrose were present in the mycelial samples in similar quantities to mannitol, but their levels decreased during fruiting. Small quantities of glucose were present in the sporophore. The results are discussed in relation to the possible functions of the soluble carbohydrates.

Proposal of a New Genus, Gordona, for Slightly Acid-fast Organisms Occurring in Sputa of Patients With Pulmonary Disease and in Soil

Abstract: SUMMARY: A new genus Gordona has been proposed for slightly acid-fast organisms which occur in sputa of patients with pulmonary disease and in soil. This genus is considered to contain ‘Mycobacterium’ rhodochrous-like organisms. The genera Mycobacterium and Gordona are characterized by absence of mycelium and slight or strong acid-fastness. The genus Gordona shows characters intermediate between the genera Mycobacterium and Nocardia. It is distinguished from rapid-growing mycobacteria by its slight acid-fastness (weaker than Mycobacterium), absence of arylsulphatase activity at 2 weeks, ability to utilize sucrose as a sole carbon source and inability to utilize trimethylene diamine as a simultaneous nitrogen and carbon source. The genus is distinguished from nocardias by the absence of mycelium, ability to form acid from mannose, positive nitrate reduction and ability to utilize sucrose as a sole carbon source. It can be isolated from sputa of patients with lung cavities or bronchiectasis and from soil by prior treatment with alkali. The organisms are Gram-positive or variable; slightly acid-fast, that is, stained light pink or light violet by the Ziehl-Neelsen method; mycelium not formed; spores not formed; non-motile; aerobic; catalase-positive; oxidase-negative; acid formed from glucose by oxidation; growth occurs at 28° and 37° but not at 45°; growth at 2 to 3 days forming rough, reddish or pinkish colonies in air; occur as short rods; non-pathogenic for mice, rabbits, guinea pigs and chickens. Type species is Gordona bronchialis.

Direct nocturnal water transfer from oaks to their mycorrhizal symbionts during severe soil drying

Abstract: Symbiotic mycorrhizal fungi play an important role in the absorption of soil nutrients and water by most plants. It has been suggested that hydraulically lifted water might maintain the integrity of the external mycorrhizal mycelium during drought. We tested this hypothesis in the obligately mycorrhizal species, coast live oak (Quercus agrifolia), using a microcosm system that separated the effects of hydraulic lift in roots from those in the external mycelium. Mycorrhizal oak seedlings were established in microcosms comprising three discrete compartments for (1) upper roots, (2) tap roots, and (3) external fungal mycelium. Eight months after planting, a drought treatment was initiated: irrigation to the upper root and fungal chambers was terminated and only irrigation to the taproot compartment was maintained. After 3, 12, 30, 50, 70 and 80 days of drought, tracers were injected into the taproot compartment at dusk. At dawn the following morning, mycorrhizal hyphae (EM and AM) and spores (AM) in upper root and fungal compartments were extensively labeled with the tracers. In contrast, no labeling was observed when tracers were injected into the taproot compartment during daytime. Nocturnal water translocation from plant to mycorrhizal fungi occurred in association with hydraulic lift. Saprotrophic/parasitic fungi in the microcosms were not labeled, suggesting a direct water transfer from plants to their mycorrhizal mutualists and not to other fungi in the soil. Even after prolonged drought (70-80 days), mycorrhizal hyphae persisted in soils with water potential values as low as -20 MPa. Maintaining mycorrhizal activity through direct water translocation could potentially improve the nutrient status of deep-rooted plants during periods when the fertile upper soil is dry.

Structures and Antitumor Activities of the Polysaccharides Isolated from Fruiting Body and the Growing Culture of Mycelium of Ganoderma lucidum

Abstract: Several β-D-glucans, appertaining to the same molecular species but having different degrees of branching, were isolated from water and alkali extracts of the fruiting body of Ganoderma lucidum (Reishi). The purified glucans that were mostly water-insoluble had a backbone of (1 →3)-linked D-glucose residues, attached mainly with single D-glucosyl units at 0-6 and also with a few short (l→4)-linked glucosyl units at 0-2 positions. However, their degrees of branching appeared to differ in the range of d.b. 1/3 ~ 1/23, depending on the extracted glucan fractions. In addition to the ^-glucans, the fruiting body contained water-soluble heteropolysaccharides, comprising D-glucose, D-galactose, D-mannose, L-(or D)-arabinose, D-xylose, and L-fucose.A branched (1 →3)-β-D-glucan was also isolated from the culture filtrate of G. lucidum grown in a glucose-yeast extract medium. The extracellular β-D-glucan was less soluble in water after purification, but soluble in dilute alkali. This glucan has essentially the same...