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.     

木材腐朽菌培养特性的研究综述

论述了研究木材腐朽菌培养特性的意义,对自1889年以来有关木材腐朽菌培养特性的研究文献进行了回顾。通过综合分析以往国内外对木材腐朽菌培养特性研究的结果,得出了对木材腐朽菌培养特性研究的总体结论。     

Primary fluorescence (Autofluorescence) of fruiting bodies of the wood-rotting fungusFomes fomentarius

Autofluorescence of fruiting bodies of the wood-rotting fungus Fomes fomentarius has been observed and is described among native macrofungi for the first time. The strongest yellow autofluorescence with blue excitation was displayed by pith sets, a weaker yellow, yellow-green to yellow-red fluorescence was due to generative thin-walled hyphae while the weakest yellow-reddish fluorescence was emitted by thick-walled skeletal hyphae (though their parts may emit a more intensive yellow fluorescence). This yellow, yellow-green to yellow-red autofluorescence was assessed to be more intensive than the emission described so far in bacteria and fungi (except for lysed hyphae of the fungus Trametes versicolor). With green excitation all F. fomentarius cells emitted strong red autofluorescence.     

Guild structure of wood-rotting fungi based on volume and decay stage of coarse woody debris

Wood-rotting fungi are major organisms exploiting coarse woody debris (CWD) in forests. Here, guild structure of wood-rotting fungi was investigated in cool temperate (Chichibu) and warm temperate (Chiba) forests in central Japan, based on their occurrence on CWD of different volumes and decay stages. Analysis with the program partitioning around medoids (PAM) recognized two clusters in Chichibu and four in Chiba, and their silhouette coefficients (an index for reliability of clustering) were adequately high, suggesting the existence of non-random clustering structure. To examine whether the clustering structure observed in this study was based on fungal preference for CWD or discontinuities in the distribution of CWD characteristics (decay stage and volume), null model analyses were made in which all fungal species were randomly redistributed among CWD. Silhouette coefficients based on the null model were reasonably high in both localities, indicating the observed clustering structure was at least partly attributable to the discontinuity in the distribution of CWD characteristics. In addition, the silhouette coefficient of the observed clustering structure was significantly higher than that of the null model in both localities. This result suggests that guild structure was present in the wood-rotting fungal communities, and the difference in CWD preference among wood-rotting fungi contributed to the structuralization of the communities.     

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.     

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.     

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.     

Evidence for a new extracellular peroxidase. Manganese-inhibited peroxidase from the white-rot fungus Bjerkandera sp. BOS 55.

A novel enzyme activity was detected in the extracellular fluid of Bjerkandera sp. BOS 55. The purified enzyme could oxidize several compounds, such as Phenol red, 2,6-dimethoxyphenol (DMP), Poly R-478, ABTS and guaiacol, with H2O2 as an electron acceptor. In contrast, veratryl alcohol was not a substrate. This enzyme also had the capacity to oxidize DMP in the absence of H2O2. With some substrates, a strong inhibition of the peroxidative activity by Mn2+ was observed. Phenol red oxidation was inhibited by 84% with only 1 mM of this metal ion. Because DMP oxidation by this enzyme is only slightly inhibited by Mn2+, this substrate should not be used in assays to detect manganese peroxidase. The enzyme is tentatively named 'Manganese-Inhibited Peroxidase'.     

Observations on the use of guaiacol and 2,2′-azino-di(3-ethylbenzthiazoline-6-sulfonic acid) as peroxidase substrates

Aging of aqueous guaiacol (o-methoxyphenol) solutions over a period of several months led to the spontaneous formation of peroxidatic compound(s) and other unidentified oxidation products of guaiacol. This accelerated the oxidation of guaiacol catalyzed by lactoperoxidase (LPO) severalfold depending on the pH of the reaction mixture. The peroxide(s) acted like H₂O₂ while the aromatic oxidation products may be more reactive than guaiacol. Five- to 12-month-old 20 mm stock solutions contained even 0.05-0.3% of H₂O₂ equivalents. The formation of the peroxidatic compound(s) was found to be a photochemical process which progressed in a few hours at 254 nm and slowly (detectable in 2-week-old solutions) in regular glass bottles kept under normal laboratory illumination. The kinetics and pH dependence of the oxidation of aged guaiacol solutions by LPO were distinctly different from those found with fresh substrate. The spontaneously formed peroxidatic compound is possibly a better oxygen donor in LPO assays than H₂O₂. The spontaneously formed aromatic oxidation products of guaiacol may include compounds that contain diphenoquinone groups. The complexity of the oxidation of guaiacol and the multitude of reaction products formed require special consideration in kinetic studies of LPO. The use of 2,2′-azino-di(3-ethylbenzthiazoline-6-sulfonic acid) as a LPO substrate was studied. The published method utilizing this substrate was modified into a more sensitive procedure by readjusting some of the reaction conditions.     

长白山多孔菌物种多样性、区系组成及分布特征

多孔菌是木材腐朽真菌的一个重要类群,通过将木材中的纤维素、半纤维素和木质素分解成为可被自身和其他生物利用的营养物质,从而促进森林生态系统中的物质循环.经过十几年的考察和采集,发现长白山地区多孔菌物种多样性非常丰富,Shannon多样性指数达到5.06,共有246种,占中国多孔菌总数的40.7％,分别隶属于担子菌门6个目11个科80个属,其中优势科为多孔菌科.物种区系地理成分以北温带成分和世界广布成分为主,其他几种区系成分也有分布,具有明显的北温带成分区系特征.松属是长白山地区多孔菌最重要的寄主树木,该地区41.5％的多孔菌生长在松属上.该地区多孔菌主要营腐生生活,其数量与生长基质腐烂程度的相关系数达到了0.89,呈显著相关,对长白山森林生态系统的物质循环起着重要作用.长白山多孔菌物种保护程度比较高,其中稀有种和濒危种的数量均相对较多,濒危种18种,占到全国濒危种数量的37.5％.多孔菌除了在森林生态系统中发挥重要生态功能外,很多种类本身具有较高的经济价值.在保护好该生物类群的前提下,可以合理开发和利用这些宝贵的生物资源.     

Production of manganic chelates by laccase from the lignin-degrading fungus Trametes (Coriolus) versicolor.

Many ligninolytic basidiomycete fungi have been shown to secrete a group of peroxidase isozymes whose sole function appears to be the peroxide-dependent oxidation of manganous [Mn(II)] to manganic [Mn(III)] ions. Manganic chelates and these Mn peroxidases have been implicated as central to the degradation of various natural and synthetic lignins and lignin-containing effluents by white rot (ligninolytic) fungi. Another group of enzymes, the laccases, are commonly secreted by wood-rotting fungi, but are generally regarded as being able to oxidize (and usually polymerize) only phenolic substrates. In this report it is shown that in the presence of appropriate oxidizable phenolic accessory substances or primary substrates, a variety of laccases and peroxidases catalyzing one-electron oxidations can also produce Mn(III) chelates from Mn(II).     

Production of manganic chelates by laccase from the lignin-degrading fungus Trametes (Coriolus) versicolor.

Many ligninolytic basidiomycete fungi have been shown to secrete a group of peroxidase isozymes whose sole function appears to be the peroxide-dependent oxidation of manganous [Mn(II)] to manganic [Mn(III)] ions. Manganic chelates and these Mn peroxidases have been implicated as central to the degradation of various natural and synthetic lignins and lignin-containing effluents by white rot (ligninolytic) fungi. Another group of enzymes, the laccases, are commonly secreted by wood-rotting fungi, but are generally regarded as being able to oxidize (and usually polymerize) only phenolic substrates. In this report it is shown that in the presence of appropriate oxidizable phenolic accessory substances or primary substrates, a variety of laccases and peroxidases catalyzing one-electron oxidations can also produce Mn(III) chelates from Mn(II).     

Ligninolytic activity of tropical rainforest basidiomycetes

A total of 116 strains of Brazilian tropical rainforest basidiomycetes were evaluated in terms of their ability to oxidize the dye rhemazol brilliant blue R (RBBR) and guaiacol. Laccase and peroxidase activities were detected by the drop test using solutions of α-naphthol and pyrogallol, respectively. RBBR and guaiacol oxidation occurred in 96.6 and 87.1% of the strains tested, respectively. One hundred strains oxidized both substrates. In the drop test, most strains presented laccase (96.6%) and peroxidase (92.2%) activity. The quick screening method used here can be useful to identify ligninolytic fungal strains to be used in various biotechnological applications. This revised version was published online in November 2006 with corrections to the Cover Date.     

一株产漆酶土壤真菌F-5的分离及土壤修复潜力

漆酶因可氧化许多种有机污染物,在土壤污染修复方面的应用潜力受到广泛重视。筛选具有较高漆酶活性的土壤真菌,可以为污染土壤修复提供生物资源。通过培养基中愈创木酚颜色反应,从土壤中筛选获得1株真菌菌株F-5。18S rRNA基因序列显示该菌株属于巨座壳科(Family Magnaporthaceae)。单因素试验和正交试验结果显示,蔗糖和蛋白胨分别是最有利于该菌产漆酶的碳源和氮源。在适当培养条件下,真菌F-5培养液酶活性可达4033U/L,表现出该菌具有较强的产漆酶能力。在多环芳烃(PAHs)污染土壤的生物修复中,真菌F-5可使土壤中苯并(a)芘、二苯并(a,h)蒽等高环、高毒性多环芳烃降解,并使土壤多环芳烃毒性当量大幅降低。因此,真菌F-5适合修复PAHs污染土壤。     

Volatile compounds from Pinus silvestris stimulating the growth of wood-rotting fungi

Summary Certain volatile organic acids stimulated the growth of Stereum sanguinolentum when added through the gas phase or to the liquid nutrient medium. Some of the acids were identified in extract of heat-treated wood of pine (Pinus silvestris), which had been shown (Suolahti, 1951) to have a growth-promoting effect on Stereum sanguinolentum and other wood-rotting fungi.The effect of volatile materials from a heat-treated piece of pine-wood and of caproic acid was tested on 13 other wood-rotting fungi. The growth of 11 of them was stimulated by volatiles from pine-wood, only 2 by caproic acid.The morphology of Coniophora cerebella was altered when volatiles from a neutral fraction of pine-wood extract was added through the gas phase.     

Capacity of Irpex lacteus and Pleurotus ostreatus for decolorization of chemically different dyes

The rate and efficiency of decolorization of poly R-478- or Remazol Brilliant Blue R (RBBR)-containing agar plates (200 μg g⁻¹) were tested to evaluate the dye degradation activity in a total of 103 wood-rotting fungal strains. Best strains were able to completely decolorize plates within 10 days at 28 °C. Irpex lacteus and Pleurotus ostreatus were selected and used for degradation of six different groups of dyes (azo, diazo, anthraquinone-based, heterocyclic, triphenylmethane, phthalocyanine) on agar plates. Both fungi efficiently degraded dyes from all groups. Removal of RBBR, Bromophenol blue, Cu-phthalocyanine, Methyl red and Congo red was studied with I. lacteus also in liquid medium. Within 14 days, the following color reductions were attained: RBBR 93%, Bromophenol blue 100%, Cu-phthalocyanine 98%, Methyl red 56%, Congo red 58%. The ability of I. lacteus to degrade RBBR spiked into sterile soil was checked, the removal being 77% of the dye added within 6 weeks. The capacity of selected white rot fungal species to remove efficiently diverse synthetic dyes from water and soil environments is documented.     

Laccase and Tyrosinase in some Wood-rotting Fungi

Several species of wood-rotting fungi have been examined forphenol oxidases. Polystictus sanguineus, a white rot, produceslaccase, secreting it into the medium. This enzyme has beenstudied and partly purified. Phellinus cryptarum, another whiterot, shows varied production of phenol oxidase according tothe medium used for growth. Laccase only is produced on maltmedium, whereas laccase and tyrosinase result after growth ona glucose and salt medium. Lentinus lepideus, a brown rot, producestyrosinase on several media and this enzyme appears to be entirelyintracellular.     

STARCH GEL ELECTROPHORESIS OF ENZYMES FROM NINE SPECIES OF POLYPORUS

Taxonomic relationships among 22 isolates of nine species of the wood-rotting fungus, Polyporus, were examined by starch gel electrophoresis, coupled with histochemical staining procedures. Crude extracts of 21-day cultures grown on malt extract agar were subjected to electrophoresis for 3 hr at a constant current of 25 ma. Esterase, peroxidase, catechol oxidase, galactose dehydrogenase, acid phosphatase, and alkaline phosphatase banding patterns were analyzed. With each enzyme, the bands for each isolate were compared with those for other isolates of the same species and for isolates of other species. A closer relationship was found in the banding patterns for different isolates of a single species than among isolates of different species. This technique may prove valuable for the evaluation of taxonomic differences among these wood-rotting fungi.     

Bats and remedial timber treatment chemicals a review

All species of bat found in Britain have declined in numbers and all are classified as vulnerable or endangered. Their habitual use of roof voids for roosting and the formation of breeding colonies brings them into close contact with structural timbers which are often treated with long-lasting pesticides to eradicate or prevent infestations of wood-boring insects or wood-rotting fungi. Some of the pesticides used have a considerable toxicity to mammals and are applied at a sufficiently high concentration to present a significant hazard to bats roosting on the treated timbers. Laboratory studies have shown that bats can be killed when they roost on timbers treated with lindane or pentachlorophenol, although some other chemicals, notably die synthetic pyrethroids, appear to be harmless. Numerous field incidents in which bats have been killed by remedial treatment chemicals emphasize the scale of the problem.     

Wood-decay type and fungal guild dominance across a North American log transplant experiment

We incubated 196 large-diameter aspen (Populus tremuloides), birch (Betula papyrifera), and pine (Pinus taeda) logs on the FACE Wood Decomposition Experiment encompassing eight climatically-distinct forest sites in the United States. We sampled dead wood from these large-diameter logs after 2 to 6 y of decomposition and determined wood rot type as a continuous variable using the lignin loss/density loss ratio (L/D) and assessed wood-rotting fungal guilds using high-throughput amplicon sequencing (HTAS) of the ITS-2 marker. We found L/D values in line with a white rot dominance in all three tree species, with pine having lower L/D values than aspen and birch. Based on HTAS data, white rot fungi were the most abundant and diverse wood-rotting fungal guild, and soft rot fungi were more abundant and diverse than brown rot fungi in logs with low L/D values. For aspen and birch logs, decay type was related to the wood density at sampling. For the pine logs, decay type was associated with the balance between white and brown/soft rot fungi abundance and OTU richness. Our results demonstrate that decay type is governed by biotic and abiotic factors, which vary by tree species.