Structure of a cell wall polysaccharide isolated from Hypocrea gelatinosa.

The structure of a polysaccharide isolated from the cell wall of Hypocrea gelatinosa has been investigated by means of chemical analyses and 1D and 2D NMR spectroscopy. The polysacharide has an irregular structure, idealized as follows: [carbohydrate structure in text].

Heterogeneity of the genus Myrothecium as revealed by cell wall polysaccharides.

The polysaccharides obtained from the alkali-extractable, water-soluble fraction (F1SS) from the cell wall of Myrothecium verrucaria and Myrothecium atroviride were shown to be composed of beta-(1-->6)-galactofuranose fully substituted at O-2 by terminal residues of alpha-glucopyranose and alpha-glucuronic acid. Glucuronic acid was substituted at O-4 by glucopyranose in the Myrothecium species M. inundatum, M. setiramosum, M. prestonii, M. tongaense and M. roridum. The acidic polysaccharides from Phaeostilbella atra (=Myrothecium atrum) and Myrothecium gramineum lacked the backbone of 2,6 di-O-substituted galactofuranose and contained a high amount of O-5-substituted beta-galactofuranose. The structures of the polysaccharides isolated from Myrothecium cinctum and Myrothecium penicilloides were unrelated to each other and to the polysaccharides from the other species analysed. The usefulness of these polysaccharides as a characteristic for delimitation of the genus Myrothecium is discussed.

Galactomannans from the cell walls of species of Paecilomyces sect. Paecilomyces and their teleomorphs as immunotaxonomic markers.

An alkali-extractable and water-soluble fraction (F1S) was obtained from cell walls of Paecilomyces variotii and species of the related genera Talaromyces, Byssochlamys and Thermoascus. The structure of the main polysaccharide of these fractions was studied and found to consist of a core of (1 --> 6)-alpha-mannopyranose partially substituted at 0.2 by chains of galactofuranose and shorter chains of mannopyranose. The differences in the regularity of the branching points and the length of the galactofuranose side chains are useful to distinguish between species. These differences were detected by immunological methods, since highly specific polyclonal antibodies were raised against these polysaccharides. Mycelium of P. variotii CBS 990.73A was stained by indirect immunofluorescence. The polysaccharides studied in this work differ from the one described for species from section Isarioidea, and this is another indication of the heterogeneity of the genus Paecilomyces.

Structural elucidation of acidic fungal polysaccharides isolated from the cell-wall of genera Cylindrocladium and Calonectria.

The structure of acidic fungal polysaccharides, isolated from the cell wall of Cylindrocladium and Calonectria species, has been investigated by chemical analysis, methylation and reductive cleavage analyses, and 1D and 2D 1H and 13C NMR spectroscopy. The polysaccharides have an idealized repeating unit: [formula: see text] linked to a small mannan core (< 5%), with n = 3 for Cylindrocladium penicilloides and C. quinqueseptatum and n = 5 for Calonectria theae, C. crotalariae, and C. colhounii.

Structure of complex cell wall polysaccharides isolated from Trichoderma and Hypocrea species.

The structure of fungal polysaccharides isolated from the cell wall of Trichoderma reesei, T. koningii, and Hypocrea psychrophila, have been investigated by means of chemical analyses and 1D and 2D NMR spectroscopy. The polysaccharides have an irregular structure, idealized as follows: [formula: see text] The proportions of the different side chains vary from a species to another, being n above some three times larger in H. psychrophila than in T. reesei or T. koningii.

An antigenic water-soluble glucogalactomannan extracted from cell walls of Paecilomyces fumosoroseus and Paecilomyces farinosus.

The water-soluble fraction (F1S) obtained after solubilizing in alkali the cell walls of four strains of Paecilomyces fumosoroseus and two of Paecilomyces farinosus amounted to 8.3-14.5% of the dry cell wall material. Two polysaccharides, F1S-A (13-20%) and F1S-B (57-68%) were separated from F1S by gel permeation through Sepharose CL-6B. 1H and 13C NMR spectra of F1S-B were recorded and showed analogous structural features in the six isolates of the two species. The fractions isolated from P. fumosoroseus strain CBS 375.70 were subjected to structural analysis and shown to be a (1-->4)-alpha-glucan (F1S-A) and a branched (1-->6)-mannan with terminal residues of beta-galactopyranose (F1S-B). Polyclonal antibodies against the latter polysaccharide were obtained (titre 1/8000). These antibodies reacted specifically with the F1S-B polysaccharides obtained from the four strains of P. fumosoroseus and the two strains of P. farinosus, but they did not react with similar fractions from other species of the same or related genera. The antibodies specifically stained P. fumosoroseus hyphae in indirect immunofluorescence tests.

Structural investigation of two cell-wall polysaccharides of Penicillium expansum strains.

The structure of two cell-wall polysaccharides isolated from three different strains of Penicillium expansum, the type species of the genus, have been established by 1D and 2D NMR spectroscopy, and also by methylation analyses. The water-soluble polysaccharide F1S-B consisted of a linear tetrasaccharide repeating unit with the following structure: [-->6)-beta-D-Galf-(1-->5)-beta-D-Galf-(1-->5)-beta-D-Gal f-(1-->5)-beta-D- Galf-(1-->]n The alkali-soluble polysaccharide F1I is a (1-->3)-alpha-D-glucan.

Structural studies of fungal cell-wall polysaccharides from two strains of Talaromyces flavus.

The water-soluble cell-wall polysaccharides isolated from strains CBS 352.72 and 310.38 of Talaromyces flavus have been investigated by chemical analyses and NMR studies. Two different skeletons coexist, having the structures: [formula:see text]. The small differences between the polysaccharides isolated from both strains are probably due to slight diminution of branching in strain 352.72, as compared with strain 310.38.

Chemical structure and conformational features of cell-wall polysaccharides isolated from Aphanoascus mephitalus and related species.

The structures of cell-wall mannans isolated from Aphanoascus mephitalus, A. fulvescens, A. verrucosus, and A. reticulisporus have been investigated by chemical analyses and 1D and 2D 1H and 13C NMR techniques. It was found that all of them consists of a relatively simple comb-like structure of the disaccharide repeating block [-->6)-[alpha-Manp-(1-->2)]-alpha-Manp-(1-->]. The conformations around the alpha-(1-->2) and alpha-(1-->6) linkages in these kinds of polymers were also studied by using molecular mechanics and dynamics calculations, together with NOE data. The results are similar to those found within the oligosaccharide chains of glycoproteins, with a well-defined conformation for the alpha-(1-->2) linkage and a certain restriction around the alpha-(1-->6) bonding imposed by the 2-substitution.

Differences in cell wall polysaccharides of several species of Eupenicillium.

A beta-(1-5)-galactofuran was isolated and characterized from fraction F1S (alkali- and water-soluble) of the cell wall of most of the species of Eupenicillium. In E. cryptum, E. euglaucum and E. nepalense the galactan contained galactofuranose with different linkages in addition to beta-(1-5). Fraction F1I (alkali-soluble, water-insoluble) was an alpha-glucan in certain species while in others it was a beta-glucan. Xylose was detected in some species in F1I or in F3 (alkali-soluble at 70 degrees C). The most abundant fraction (F4), resistant to the alkali treatment, was a beta-glucan-chitin complex. Excepting this component, the beta-(1-5)-galactofuran was the polysaccharide which appeared more frequently in the cell wall of species of Eupenicillium and it may have chemotaxonomic relevance.

Chemical and structural similarities in wall polysaccharides of some Penicillium, Eupenicillium and Aspergillus species.

Various fractions were extracted from cell-wall material of Eupenicillium crustaceum, Penicillium brevi-compactum, P. decumbens, Aspergillus flavipes and A. ochraceus. The most characteristic fractions, which may have chemotaxonomic relevance, were F1I, an alpha-(1-3) glucan (alkalisoluble, water-insoluble), which amounted to 16.2-32.5% of the cell-wall material, and F1S (alkali and water-soluble) which represented 2.5-6.2% of the cell-wall material and was identified as a beta-(1-5) galactan. 13C-NMR spectra of the F1S fractions showed the same pattern for all the fungal species, characteristic of beta-(1-5) linked galactofuranose.

Carbohydrate stability during ageing in Penicillium expansum cell wall.

Cell walls were obtained from Penicillium expansum mycelia of different ages. The yield of walls increased up to the 13th day of incubation and then remained almost constante. Cell walls from 13 day-old mycelia consisted of neutral sugars (65%), chitin (10%) and protein (10%). The neutral sugars released by hydrolysis of the cell wall, identified and quantified by gas-liquid chromatography were mannose (3-4%), galactose (3-4%), glucose (37%) and trace amounts of arabinose and xylose. The contents of chitin remained constant during ageing. Alkali treatment at 20 degrees C of the cell wall released and alpha-glucan amounting to about 30% leaving an insoluble residue formed by chitin and a beta-glucan containing mannose and galactose.