Observations on cell walls of yeasts and some other fungi by X-ray diffraction and solubility tests

A purified wall fraction was prepared from the mycelium of Agaricus bisporus. The isolated wall consisted of 43",, (wiw) chitin, 1 4 "~) KOH-soluble glucan, 27Oh /I-glucan, 1 6 O , protein and ~-5~) , , lipid. Traces of mannose and xylose were detected by gas chromatography. The architecture of the wall was investigated with sequential enzyme digestion and electron microscopy. The outer wall surface is covered by a mucilage that is removcd by the isolation procedure. The wall fraction could be completely degraded by extraction in warm I M-KOH followed by digestion with a mixed /,'-glucanase and then chitinase. The outer layer of KOHsoluble glucan is amorphous and or variable thickness. Incubation with glucanase did not change the dimensions of the wall but was necessary before the inner wall was susceptible to attack by chitinase, indicating that />'-glucan does not constitute a separate wall layer but is a matrix associated with the fibrillar chitin. The inner layer presents an even, compact. fibrillar side as the inside surface of the wall, but is looser and uneven outwardly where it interdigitates with the irregular inner surface of the KOH-soluble glucan. Silver hexamide staining showed cystine-containing protein throughout the wall.The fruit body of the Agaricales is massive, yet mainly consists of relatively undifferentiated hyphal elements similar to the vegetative mycelium, and thus provides an interesting system for studying the mechanisms of hyphal aggregation i n morphogenesis. A number of striking correlations between fungal cell form and wall composition, particularly in such phenomena as hyphal-yeast cell type dimorphism, emphasize the importance that wall composition may have in determining dif'ferentiation and rnorphogenesis (Smith & Galbraith, 1971). The composition and architecture of the hyphal wall is now known in a variety of fungi, but a more or less complete picture is available for only one near relative of the mushrooms, Schizopliyllrrm co~iiniuno, a member of the Aphyllophorales. We present here a study of the hyphal architecture 01' the common mushroom, Agirricus bisyorus, and compare and relate it to S. coyIztizunc and the existing fragmentary picture in the Agaricales itself.

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“…Kreger (1954) reported 30 to 3500 (w/w) chitin in A . car~pc~.stvis (wniewhat below the 43(),, found i n A .…”

Section: Discussionmentioning

confidence: 99%

Chemistry and Architecture of the Mycelial Wall of Agaricus bisporus

Michalenko

Hohl

Rast

1976

Journal of General Microbiology

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“…With the availability of physical methods for isolating cell walls, the chemical complexity of the walls of fungi has now been clearly realized. In addition to chitin or cellulose, various carbohydrates, proteins, lipids, and other components have been found in the cell walls of moulds (Kreger, 1954 Wessels, 1965;etc.). The majority of filamentous fungi have chitinous walls.…”

Section: Introductionmentioning

confidence: 99%

Chemistry of Hyphal Walls of Phytophthora

Bartnicki-García¹

1966

Journal of General Microbiology

121

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SUMMARYHyphal walls of two phytopathogenic moulds, Phytophthora cinnamomi and P. parasitica, were isolated essentially free from cytoplasmic contamination. They have a complex chemical structure consisting of polysaccharide, protein and lipid. D-Glucose was the main monosaccharide detected in acid hydrolysates. Chromatographic evidence suggested the presence of small amounts of mannose (0-6y0), glucosamine (0.3%) and traces of galactosamine and ribose. Glucans constituted nearly 90 yo of the wall but only about a maximum 25 yo of the wall could be regarded as cellulose I on the basis of solubility, resistance to hydrolysis and X-ray diffraction. Most of the wall glucan exhibited chemical and physical properties unlike typical cellulose.The spectrum of amino acids commonly found in fungal walls was detected ; hydrolysates also contained hydroxyproline and two minor unidentified ninhydrin-positive components. Protein comprised 3-5 yo of the wall, A small amount of lipid (1-3 yo), mostly of the bound type, was found, and also traces of phosphorus, and compounds with absorption maxima at 263mp. Hyphal walls of Phytophthora cinnamomi and P. parasitica differed only slightly in quantitative composition.

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“…The edible mushroom Agaricus bisporus (Lange) Imbach contains chitin in its cell walls (Kreger, 1954;Michalenko, Hohl & Rast, 1976). To determine if chitin synthase activity is involved in mycelial growth and fruit body expansion of A. bisporus, we have examined the effect of polyoxin D on these processes.…”

Section: Introductionmentioning

confidence: 99%

“…The development of sporophores of the basidiomycete Coprinus cinereus has been shown to require chitin synthase activity (Gooday, I972 ; Gooday, de Rousset-Hall & Hunsley, 1976). These authors found that sporophore development of C. cinereus was inhibited by concentrations of polyoxin D similar to those which inhibited the activity of chitin synthase preparations in vitro.The edible mushroom Agaricus bisporus (Lange) Imbach contains chitin in its cell walls (Kreger, 1954;Michalenko, Hohl & Rast, 1976). To determine if chitin synthase activity is involved in mycelial growth and fruit body expansion of A. bisporus, we have examined the effect of polyoxin D on these processes.…”

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confidence: 99%

Inhibition of Growth and Development of Agaricus bisporus by Polyoxin D

Wood¹,

Hammond²

1977

Journal of General Microbiology

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I N T R O D U C T I O NThe antibiotic polyoxin D specifically inhibits chitin synthase in fungi (Corbett, 1974). The development of sporophores of the basidiomycete Coprinus cinereus has been shown to require chitin synthase activity (Gooday, I972 ; Gooday, de Rousset-Hall & Hunsley, 1976). These authors found that sporophore development of C. cinereus was inhibited by concentrations of polyoxin D similar to those which inhibited the activity of chitin synthase preparations in vitro.The edible mushroom Agaricus bisporus (Lange) Imbach contains chitin in its cell walls (Kreger, 1954;Michalenko, Hohl & Rast, 1976). To determine if chitin synthase activity is involved in mycelial growth and fruit body expansion of A. bisporus, we have examined the effect of polyoxin D on these processes. We have also examined the effect of cycloheximide, a protein synthesis inhibitor. METHODS Organism. Agaricus bisporus strains ~6 2 1and ~6 4 9 were used. These are of direct commercial origin.Assessment of inhibition of colony growth. Cultures of A . bisportts strain ~6 2 1 were inoculated on to malt agar plates (Wood, 1976). Polyoxin D was incorporated into the plates before inoculation by spreading 0-2 ml of sterile filtered solutions of polyoxin D on to the surface of the medium. Concentrations are expressed as those present in the agar. After inoculation the plates were incubated at 25 "C and colony diameters were measured at intervals. Ten replicate plates were measured for each treatment.Treatment of growing and excised sporophores. Growing sporophores were treated by injecting sterile solutions of polyoxin D into the stipe base. Approximately 40 pl containing 200 pg polyoxin D was introduced into the sporophore. Alternatively, sporophores were harvested at about stage 2 of development (Hammond & Nichols, 1976) by cutting across the stipe approximately I cm below the velum. Measurements were made of the stipe length and cap diameter, using calipers. The sporophores were then placed with the cut stipe ends dipping into small beakers containing 2 ml of solutions of polyoxin D at 2,20 or roo pg ml-1, cycloheximide at roo pg ml-l or distilled water. The sporophores and beakers were kept in chambers at 90% relative humidity for 2 days. During this period all of the solution was imbibed. The sporophores were then removed and the cap and stipe were measured again.Chitin content. The treated sporophores were separated into cap, lower stipe and upper stipe tissues. Samples of these were homogenized in distilled water. Duplicate samples of the homogenate were removed and dried to constant weight. Other samples of the homogenate were treated with 10% (w/v) NaOH at roo "C for 30 min and centrifuged at 6000 g for 10 min. The pellets were treated with 2% (vlv) HC1 at 20 "C for I h, centrifuged and then 40-3

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Observations on cell walls of yeasts and some other fungi by X-ray diffraction and solubility tests

Cited by 180 publications

References 12 publications

Chemistry and Architecture of the Mycelial Wall of Agaricus bisporus

Chemistry and Architecture of the Mycelial Wall of Agaricus bisporus

Chemistry of Hyphal Walls of Phytophthora

Inhibition of Growth and Development of Agaricus bisporus by Polyoxin D

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