Volatile constituents of wood-rotting basidiomycetes

Phytochemical investigation of the hydrodistillation products of the basidiomycetes Fomitopsis pinicola, Piptoporus betulinus, Gloeophyllum odoratum and Trametes suaveolens led to the identification of numerous mono- and sesquiterpenes as well as many aliphatic alcohols, aldehydes and ketones and some aromatic compounds. In addition, some diterpenes were identified as constituents of Fomitopsis pinicola. The absolute configuration of some terpenes was determined     

A selective medium for the isolation of wood-rotting basidiomycetes

A selective medium for growing wood-rotting basidiomycetes is described. The medium is based on a mixture of benomyl and 2-phenylphenol which suppresses the growth of lower fungi and Sistotrema brinkmannii, a basidiomycete of frequent occurrence in timber but one which cannot decay wood. Use of the medium in isolation studies permits a higher recovery of wood-rotting basidiomycete fungi than can be achieved by the use of other selective media.     

Copper sorption by native and modified pellets of wood-rotting basidiomycetes

AIMS: The aim of this study was to investigate the biosorption of copper to the pellets of different wood-rotting fungal species. METHODS AND RESULTS: Copper sorption was studied in both batch and column arrangements. The optimum pH for copper sorption was between 3.5 and 4. In 100 mg l(-1) Cu (II), maximum qe values were found for Oudemansiella mucida (8.77 mg g(-1) dry wt), Lepista nuda (6.29 mg g(-1)), Pycnoporus cinnabarinus (5.08 mg g(-1)) and Pleurotus ostreatus (4.77 mg g(-1)). Both biomass yield and specific sorption were influenced by the composition of the fermentation broth. The results of column experiments showed that mycelial pellets of wood-rotting fungi can be considered as promising biosorbent material. CONCLUSIONS: Pellets of wood-rotting fungi showed the same or better copper sorption properties as those previously reported for lower fungi or filamentous bacteria, as well as good mechanical properties.     

Effect of heavy metals on the growth of selected wood-rotting basidiomycetes

Mercury, cadmium and cobalt were found to be the most toxic heavy metals, inducing strong growth inhibition of the tested basidiomycetes. The studied species differed significantly in their sensitivity to cadmium. The most sensitive fungus,Inonotus obliquus, did not grow at Cd concentrations higher than 0.1 mmol/L, whereasStereum hirsutum grew at more than 2 mmol Cd/L. Changes in mycelial morphology were observed inS. hirsutum andTrametes versicolor cultivated in the presence of cadmium and mercury. The toxicity of heavy metals was lower in rich, complex media. Presented at the 4th Mini-Symposium on Biosorption and Microbial Degradation, Prague, Czech Republic, November 26–29, 1996.     

Screening for pectinolytic activity of wood-rotting basidiomycetes and characterization of the enzymes

Seventy-five fungal strains from different groups of basidiomycetes, newly isolated from rotten wood, were screened for pectinolytic activity. Despite the fact that basidiomycetes are scarcely referred to as pectinase producers, the polygalacturonase (PG) activity was detected in 76% of the strains; 16% with activity higher than 40 nkat/g, 40% between 13.3 and 40 nkat/g, and 44% with activity lower than 13.3 nkat/g. The highest productions were obtained among the fungi from order Aphyllophorales, family Polyporaceae. The characterization of the enzymes from the highest PG producers (Lentinus sp., Gloeophyllum striatum, Pycnoporus sanguineus, Schizophyllum commune) showed optimum temperature for catalytic activity at 60-70 degrees C and two peaks of pH optimum (3.5-4.5 and 8.5-9.5). The enzymes exhibited high pH stability (3.0-11.0) but after incubation at 40 degrees C for 1 h their activity dropped by 18-73%.     

耳状网褶菌的化学成分

从野生真菌耳状网褶菌（Paxillus pamuoides Fr.)子实体中分得4个化合物,经光谱和化学方法分别鉴定为（2S,3S,4R,2′R）-2－（2′－羟基二十四碳酰氨基）十八碳－1,3,4－三醇（1）、5α,8α－表二氧－（22E,24R）－麦角甾－6,22－二烯－3β-醇[5α,8α-epidioxy-(22E,24R)-ergosta-6,22-dien-3β－o1,2]、（22E,24R）－麦角甾－4,6,8（14）,22－四烯－3－酮[(22E,24R)-ergosta-4,6,8(14),22-tetraen-3-one,3]和对羟基苯甲酸乙酯（ethyl 4-hydroxybenzoate,4)。其中化合物4作为天然产物属首次报道。化合物1－4为本科真菌中首次分得。     

A proposed role of oxalic acid in wood decay systems of wood-rotting basidiomycetes

Abstract: The possible roles of oxalic acid, veratryl alcohol, and manganese were investigated in relation to lignin biodegradation by white-rot basidiomycetes. Oxalate inhibited both lignin peroxidase (LiP) and manganese-peroxidase (MnP). and was decarboxylated by the mediation of veratryl alcohol and Mn. Oxalate was shown to regulate the mineralization of lignin in the in vivo system of Phanerochaete chrysosporium . In the brown-rot wood decay process, oxalic acid may serve as an acid catalyst as well as an electron donor for the Fenton reaction, to breakdown cellulose and hemicellulose. Oxaloacetase and glyoxylate oxidase may play a key role in production of oxalic acid by white-rot and brown-rot basidiomycetes such as Phanerochaete chrysosporium, Coriolus versicolor and Tyromyces palustris . A possible role of oxalate metabolism is discussed in relation to the physiology of wood-rotting fungi.     

Sulphur oxidation by soil fungi including some species of mycorrhizae and wood-rotting basidiomycetes

Abstract The mycorrhizal fungi Amanita muscaria, Paxillus involutus, Hymenoscyphus ericae, Pisolithus tinctorius, Rhizopogon roseolus , and Suillus bovinus oxidized elemental sulphur to thiosulphate and sulphate in vitro. In some, but not all cases, tetrathionate was also formed. Limited oxidation of elemental sulphur by R. roseolus also occurred when growing in association with Pinus contorta in unsterilized peat. Although yeasts capable of oxidizing sulphur could not be isolated from a wide range of soils, a yeast-like fungus ( Monilia sp.) isolated from deciduous woodland soil oxidized elemental sulphur to sulphate, forming thiosulphate, but not tetrathionate. This fungus also oxidized tetrathionate to sulphate but showed only limited ability to oxidize thiosulphate to tetrathionate. Both Aspergillus niger and Trichoderma harzianum oxidized elemental sulphur in mixed culture with Mucor flavus . Larger amounts of sulphate were initially formed in mixed, compared to single culture; but by week 5 of the incubation period sulphate formation was greatest in single culture. The wood-rotting fungi, Hypholoma fasciculare and Phanerochaete velutina showed a limited ability to oxidize elemental sulphur in vitro but were incapable of oxidizing the element when growing as mycelial cords in non-sterilized soils. The relevance of these results to the possibility that fungi play a role in sulphur oxidation in soils is commented upon.     

The production of extracellular mucilaginous material (ECMM) in two wood-rotting basidiomycetes is affected by growth conditions

The ability of two wood-decay basidiomycetes to produce extracellular mucilaginous material (ECMM) and its relationship with total biomass production has been investigated. Growth and ECMM production by the white-rot fungus Coriolus versicolor and the brown-rot fungus Gloeophyllum trabeum were assessed in liquid culture under different nutritional and environmental conditions. Nutritional, pH and temperature factors all influenced significantly the proportion of ECMM in the total biomass produced. When total biomass production was reduced due to unfavorable growth conditions (stress), the proportion of ECMM in the biomass was elevated. The results are discussed with regard to the possible role(s) of ECMM in the responses of these fungi to stress.     

Qualitative and quantitative changes of beech wood degraded by wood-rotting basidiomycetes monitored by Fourier transform infrared spectroscopic methods and multivariate data analysis

Beech wood (Fagus sylvatica L.) veneers were cultivated with white and brown rot fungi for up to 10 weeks. Fungal wood modification was traced with Fourier transform near infrared (FT-NIR) and Fourier transform mid infrared (FT-MIR) methods. Partial least square regression (PLSR) models to predict the total lignin content before and after fungal decay in the range between 17.0% and 26.6% were developed for FT-MIR transmission spectra as well as for FT-NIR reflectance spectra. Weight loss of the decayed samples between 0% and 38.2% could be estimated from the wood surface using individual PLSR models for white rot and brown rot fungi, and from a model including samples subjected to both degradation types.     

Features of lipogenesis of basidiomycetes Pleurotus ostreatus and Flammulina velutipes in cultures on various media

The compositions of free fatty acids (FA) in the mycelia of oyster cap (Pleurotus ostreatus (Jacq. ex Fr.) Kumm.) and honey mushroom (Flammulina velutipes (Curt. ex Fr.) Sing.) and the effect of mycelium cultivation conditions on the composition and proportions of individual FA were investigated. Palmitic and linoleic acids were found to be major acids produced by P. ostreatus growing on solid agar medium and in a submerged culture with a synthetic medium. The composition of minor FA in P. ostreatus was dependent on cultivation conditions. Surface cultivation of its mycelium yielded pentadecanoic, octadecenoic, and stearic acids. Submerged cultivation additionally yielded undecanoic, myristic, hexadecenoic, and lignoceric acids. The composition of free FA in F. velutipes showed no significant differences from that of P. ostreatus. Variation in the C/N ratio in the cultivation medium affected both the FA composition in P. ostreatus and F. velutipes and the relationship between saturated and unsaturated FA.     

Amatoxins in wood-rotting Galerina marginata

Amatoxins, bicyclic octapeptide derivatives responsible for severe hepatic failure, are present in several Basidiomycota species belonging to four genera, i.e. Amanita, Conocybe, Galerina and Lepiota. DNA studies for G. autumnalis, G. marginata, G. oregonensis, G. unicolor and G. venenata (section Naucoriopsis) determined that these species are the same, supporting the concept of Galerina marginata complex. These mostly lignicolous species are designated as white-rot fungi having a broad host range and capable of degrading both hardwoods and softwoods. Twenty-seven G. marginata basidiomes taken from different sites and hosts (three sets) as well as 17 A. phalloides specimens (three sets) were collected in French locations. The 44 basidiomes were examined for amatoxins and phallotoxins using high-performance liquid chromatography. Toxinological data for the wood-rotting G. marginata and the ectomycorrhizal A. phalloides species were compared and statistically analyzed. The acidic and neutral phallotoxins were not detected in any G. marginata specimen, whereas the acidic (β-Ama) and neutral (α-Ama and γ-Ama) amanitins were found in all basidiomes from either Angiosperms or Gymnosperms hosts. The G. marginata amatoxin content varied from 78.17 to 243.61 μg.mg(-1) of fresh weight and was elevated significantly in one set out of three. The amanitin amounts from certain Galerina specimens were higher than those from some A. phalloides basidiomes. Relationship between the amanitin distribution and the chemical composition of substrate was underlined and statistically validated for the white-rot G. marginata. Changes in nutritional components from decayed host due to enzymatic systems and genetic factors as well as environmental conditions seem to play a determinant role in the amanitin profile. Variability noticed in the amanitin distribution for the white-rot G. marginata basidiomes was not observed for the ectomycorrhizal A. phalloides specimens.     

Antibiotics from basidiomycetes

Three new antibiotically active metabolites were isolated from cultures of the fungus Pleurotellus hypnophilus. The structures which are closely related to the coriolins were elucidated by spectroscopic methods. Hypnophilin (1) has a hirsutane sceleton whereas pleurotellol (2) and pleurotellic acid (3) are sesquiterpenoids with novel hirsutane skeletons. The common structural feature of all three metabolites is an -methylene ketone moiety. The antibiotics inhibited the growth of several bacteria as well as of some fungi. In cells of the ascitic form of Ehrlich carcinoma RNA and DNA syntheses were more affected than protein synthesis. The mode of action was compared with the antimicrobial and cytotoxic effects of complicatic acid (4) and other -methylene ketones and lactones from higher plants. All the compounds tested reacted rapidly with cysteine to form adducts which were almost devoid of biological activity.Abbreviations ECA-cells Ehrlich carcinoma ascitic cells - MIC Minimal inhibitory concentration - MNNG N-methyl-N-nitro-N-nitrosoguanidine Antibiotics from Basidiomycetes. XIII. T. Anke, W. H. Watson, B. M. Giannetti, and W. Steglich: The alliacols A and B from Marasmius alliaceus (Jacq. ex Fr.) Fr. J. Antibiotics, submitted     

Enzymatic activity of basidiomycetes

In mycelial acetone powder of the basidiomyceteOudemansiella mucida, the presence of enzymatic systems of NADH₂-oxidase and-dehydrogenase type and of NAD⁺-dependent alcoholdehydrogenase (using ethanol as substrate) has been detected. NADH₂-oxidase has its optimal pH value in the region of 6,0 and is not too active. NADH₂-dehydrogenase which reduces 2,6-dichlorophenolindophenol is very active, may be eluted from the mycelial preparation with water and its adequate pH is in the region of 6,2. On the other hand, NADH₂-dehydrogenase reducing triphenyltetrazolium chloride is non-eluable with water, its activity depends on the presence of menadione and its adequate pH lies in the region of 7,4.     

Polysaccharides of xylotrophic basidiomycetes

Physicochemical properties, composition, and structure of the polysaccharides synthesized by the fungi Lentinus edodes, Ganoderma lucidum, and Crinipellis schevchenkovi in a submerged culture were studied. It has been demonstrated that the exo-and endopolysaccharides of submerged mycelia of the fungi studied are similar to the β-1,3-D-glucans of the fruiting bodies.     

Distribution of acetyl esterase in wood-rotting fungi

The distribution of acetyl esterase was studied in 30 strains of wood-rotting fungi. A screening test on agar plates using glucose β-d-pentaacetate as a substrate indicated that all tested fungi produced acetyl esterase to form a clear zone on the culture. All fungi also showed positive responses in an agar test using carboxymethyl cellulose acetate. Enzyme assay showed that extracellular acetylxylan esterase activity was present in the filtrates of wood-meal culture of all these fungi. The ratio of fungal acetylxylan esterase activity to 4-nitrophenyl acetyl esterase activity were higher than that of porcine liver esterase, indicating that fungal esterases have high affinity for acetylated carbohydrates. Acetyl esterase is suggested to be distributed widely in wood-rotting fungi for degradation of native acetylated hemicelluloses.     

Diversity and ecology of wood-inhabiting aphyllophoroid basidiomycetes on fallen woody debris in various forest types in Switzerland

This study on the ecology of aphyllophoroid wood-inhabiting basidiomycetes in Switzerland showed a remarkably high species diversity of both saprophytes and mycorrhiza-forming species. Phlebiella vaga, a saprophytic species, and Amphinema byssoides, a mycorrhizal symbiont, were the two most abundant species. A total of 3339 samples of fungal fruitbodies in 86 plots distributed all over Switzerland belonged to 238 species. The five main biogeographical regions of Switzerland showed different pattern of fungal species richness: while the Plateau at lower altitudes was found to be rather rich, the Northern Alps and Central Alps, with the highest amount of forests cover, yielded less species. Although the Southern Alps exhibited the lowest species richness, this region harbours a specific species set. These findings encourage for further studies in Central Europe, where many species of aphyllophoroid wood-inhabiting basidiomycetes seem to be highly under-investigated.