Polysaccharides fungal

Fungal polysaccharides include homopolysaccharides as well as heteropolysaccharides including D-galacto-D-mannans, D-xylo-D-mannans, etc. Scleroglucan is used as an industrial gum. Several homopolysaccharides found in fungi are shown in Table 7.11.1. 

A few pyrolysis studies done on yeasts and yeast-like fungi did not attempt to analyze individual polysaccharides but to obtain a fingerprint characterization [67], It was also common to use statistical techniques such as factor analysis for the data interpretation. It was not unusual to find N-acetylamino sugar units in fungal polysaccharides. These units showed characteristic peaks in Py-MS that allowed the distinction of different materials. 

The secretion of polysaccharides by growing hyphae of Achyla bisexualis has been studied. The cell walls of Agaricus bisporus contain chitin and a D-glucan cellobiose octa-acetate was isolated from acetolysates of the D-glucan, indicating 

Methylation analysis and n.m.r. spectroscopy have indicated that a gelforming jS-D-glucan from Pleurotus ostreatus consists of a (1 - 3)-linked chain, to which side-chains of cx-(l 4)-D-gIucosyl residues are attached. A multiple-strand helix is considered to be the most likely conformation of this -D-glucan. Chemical analysis and studies of the ultrastructure of Pythium debaryanum have indicated that the cell wall is constructed of cellulosic microfibrils, which exist both as a framework and as a finer network.The microfibrils are covered by matrix material composed of a mixture of amorphous (1 - 3)- and (1 - 6)-linked, branched jS-o-glucans. 

Wang and S. Bartnicki-Garcia, Arch. Biochem. Biophys., 1976, 175, 351. 

The cell walls of spores of Trichoderme viride contain (1 3)- and (1 - 6)- 

The association of chitin, D-glucan, and D-mannan in the cell walls of Candida albicans and the spatial distribution of these polysaccharides have been found to vary appreciably between two dimorphs and with the age of the culture.  

Cell Walls.—Aspects of the biosynthesis of fungal cell walls, including the roles of chitin and chitin synthase, have been reviewed.-  

A mixture of polysaccharides, including a galactomannan, (1 3)-a-D-glucan, and a branched (1 - 3)-P-D-glucan, has been extracted with dilute alkali from the cell walls of Schizosaccharomyces pombe. The alkali-insoluble residue contained a lightly branched (1 3)-P-Drglucan and small amounts of an extremely 

A mutation in Aspergillus nidulans resulted in loss of both melanin and (1 - 3)-a-D-glucan (a principal cell-wall polysaccharide) and prevented the formation of cleistothecia. The cell walls of the mutant strain contained more (1 3)-p- 

D-glucan and D-galactans than those of the parent strain. Examination of the cell walls of A. niger and A. awamori by X-ray methods, electron microscopy, and enzymic techniques showed that chains of nigeran occupy, at least, three domains or configurations in the hyphal walls and that they form a highly crystalline arrangement in situ.  

Mannans.—The chemistry, structures, and biosynthesis of D-mannans in the cell-wall envelopes of yeasts have been reviewed. 

Specific areas of the chemistry and biochemistry of fungi have been reviewed the autolysis of fungi including the degradation of carbohydrates, the bio- 

Hamada, T. Ooshima, S. Kotani, and K. KatO, Mierobiol. Immunol., 1979, 23, 319. 

Fractions from the cell wall and protoplasts of Aspergillus fumigatus have been shown to contain common antigenic components.Differences in both immunological reactivity and chemical structure may be linked to their cellular location and may reflect incomplete structures in the process of biosynthesis and transfer to wall sites where they become immobilized. 

In the presence of 2-deoxy-D-arabinohexose, Rhodosporidium toruloides synthesizes higher proportions of D-glucan and chitin, while the relative contents of D-mannan and D-galactan decrease drastically. 

The relationship between the chemical structure and anti-tumour activity of D-glucans prepared from Grifora umbellata has been investigated. The antitumour D-glucans appear to contain the basic structural unit (29) although the length of the branches, branching frequency, molecular size, and molecular 

Barkai-Golan, D. Mirelman, and N. Sharon, Arch. Mikrobiol., 1978, 116, 119. 

The structures of a water-soluble D-glucan (20) and an alkali-soluble d-glucan (21) from the fruit body of Auricularia auricula-judae have been established. The structural resemblance of polysaccharides from Tremella fuciformis to those of other Tremella species and the group Cryptococcus is 

Kakuta, and A. Misaki, Agric. and Biol. Chem. Japan), 1978, 42, 417. 

During the re-synthesis of the cell-wall region by protoplasts of Schizo-saccharomyces pombe, synthesis of /8-D-glucan has been found to precede synthesis of (1 3)-a-D-glucan. D-Glucans, referred to as elicitors, but so 

Mannans.—Two classes of mutants of Kluyveromyces lactis have been isolated and used to study the incorporation of 2-acetamido-2-deoxy-D-glucose into a mannan, which, in the parent yeast, contains side-chains of structure (21), One of the 

A nearest-neighbour analysis of the products of partial acetolysis of S. cerevisiae mannan has been carried out in an attempt to learn whether the side-chains are in ordered or in random sequences. The results suggested that the 

Polysaccharides composed of D-mannosyl and phosphate residues (5 1) have been isolated and purified from cells of Candida intermedia and Torulopsis famata. D-Mannose 6-phosphate was released on mild hydrolysis with acid, possibly by cleavage of a phosphodiester bond linking it to C-1 of an adjacent D-mannosyl residue. 

A purified extracellular heteroglycan obtained from cultures of Cladosporium tricoides is composed of D-galactosyl, D-glucosyl, D-mannosyl, and L-rhamnosyl residues. Periodate oxidation. Smith degradation, and methylation analysis indicated that the polysaccharide (25) is highly branched. 

Cytochemical staining, by a method involving oxidation with periodate and reaction with thiosemicarbazide and osmium tetroxide, has revealed the presence of polysaccharide lamellae on the surface of the cell membrane of Claviceps purpurea.The membranous clusters in vacuolar bodies of the endoplasmic reticulum membranes, tonoplasts, and cytoplasmic membranes are covered with these lamellae. Somatic and metabolic polysaccharides composed of D-mannose and L-rhamnose have been isolated from Certocystic stenoceras and Sporotrichum schenckii , chemical and immunological analyses indicated close similarities in their structures. When pseudoplasmodia of Dictyostelium discoideum were incubated with 2-acetamido-2-deoxy-D-[ H]glucose, the label was incorporated into a polysaccharide in the slime sheath. The incorporated label disappeared 

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Krestin (PSK) (Japan) Fungal polysaccharide Macrophage activator Gastric/other cancers... 

Fungal polysaccharides, 20 455, 577-578 Fungi. See also Soil fungi alkaloids in, 2 75... 

Streptomycin, chemistry of, 3, 337-384 Structural chemistry, of fungal polysaccharides, 23, 367-417 of the hemicelluloses, 14, 429-468 Structure, molecular, of cellulose, 19, 219-246 of dextran, 15, 341-369 of glycogens, 12, 261-298 of polysaccharide gels and networks,... 

To increase production and facilitate isolation, plant cells have been immobilised on various matrices such as polyurethane foam and calcium alginate gel beads,24 while elicitation (i.e. the induction of a defence response) is generally critical for the production of secondary metabolites. The rationale for the use of elicitors is that plants produce secondary metabolites as part of a defence response to stress, either biotic (pathogen infection) or abiotic (ultraviolet, toxic heavy metals and rare earth ions). Jasmonic acid plays a crucial role in plant stress responses and, along with fungal polysaccharides and heavy metals, is the most widely employed elicitor in plant tissue cultures.30... 

Another biochemical topic, the biochemistry of plant galacto-mannans, is discussed by Dey (Egham, Surrey) the article rounds out aspects of the field that are complementary to those treated by Gorin and Spencer in Volume 23 (on fungal polysaccharides) and Dea and Morrison in Volume 31 (on the chemistry and interactions of seed galactomannans). 

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