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SEM investigation of the production of extracellular mucilaginous material (ECM) by some wood inhabiting and wood decay fungi when grown in wood
1997 - IRG/WP 97-10193
Previous reports have illustrated the involvement of extracellular mucilage (ECM) in wood decay by Basidiomycetes. Its production is investigated in a range of stain, mould and soft rot fungi in Corsican pine, Scots pine and European beech. Fungi examined were: Chaetomium globosum, Ceratocystis coerulescens, Trichoderma harzianum, Ophiostoma piceae, Mucor sp. and Penicillium. sp. The samples were examined in the frozen hydrated (FH) and freeze dried (FD) conditions using SEM. Most of the fungi tested produced ECM with the amounts produced varying from one fungus to the other. Different morphological forms of the mucilage were observed. ECM produced by C. coerulescens was mostly fibrillar, and interesting morphological forms of the ECM were associated with hyphae of T. harzianum. Small amounts of mucilage were produced by O. piceae and Penicillium sp. Further investigation is necessary on the ECM production in Mucor sp.
A R Abu, D J Dickinson, R J Murphy

SEM investigation of the production of extracellular mucilaginous material (ECM) by some wood inhabiting and wood decay fungi when grown on inert surfaces
1997 - IRG/WP 97-10194
A range of wood inhabiting and wood decay fungi have been studied for their production of extracellular mucilage when grown on inert surfaces, for comparison with their growth on wood. The species tested were: Coniophora puteana, Coriolus versicolor, Chaetomium globosum, Trichoderma harzianum, Ceratocystis coerulescens, Ophiostoma piceae, Mucor sp. and Penicillium sp. They were grown on plastic meshes, melinex sheets and glass cover slips and were examined in the freeze dried (FD) and frozen hydrated (FH) conditions. For most of the fungi tested, the ECM production was induced upon contact with the inert surface, although the amount of the ECM produced was far less than that produced by the same fungi in wood. The ECM produced by C. puteana and C. versicolor was similar and more extensive, when compared to that produced by the other fungi. ECM was not produced by Mucor sp. and Penicillium sp.
A R Abu, R J Murphy, D J Dickinson

Sequestration of copper ions by the extracellular mucilaginous material (ECMM) of two wood rotting basidiomycetes
2004 - IRG/WP 04-10533
The radial growth rate of colonies originating from either whole or ECMM-free inocula of Coriolus versicolor was investigated. The presence of ECMM allowed colonies to maintain higher growth rates than those form ECMM-free inocula up to 2 mM CuSO4 in the medium. The ECMM of C. versicolor and G. trabeum was able to reduce the diffusion of copper ions in solution. The ‘raw’ ECMM of both fungi had a greater ability to reduce the diffusion of copper ions than ECMM which had been subject to dialysis to remove soluble, low molecular weight components. The ‘insoluble’ fraction of ECMM for both species was more effective than the ‘soluble’ fraction at reducing the diffusion of copper ions. It is concluded that ECMM confers some protection to hyphae against the toxic effects of copper ions on growth in vivo and that this due to the binding of copper ions to both the polysaccharide and to low molecular weight components of the ECMM
D Vesentini, D J Dickinson, R J Murphy

Effects of cyproconazole and copper sulphate on the length of the hyphal growth unit (HGU) of the white-rot fungus Coriolus versicolor
2003 - IRG/WP 03-10473
Wood decay basidiomycetes have been shown to produce appreciable quantities of extracellular mucilaginous materials (ECMM). The relationship between ECMM and total biomass production has been investigated in the white-rot fungus Coriolus versicolor (CTB 863 A). Differences in the amount of ECMM produced by the fungus proportionally to the total biomass, were observed under a range of physiological conditions, including the presence of biocides. Such differences suggest that stress may have a role in stimulating an increase in the amount of ECMM produced by C. versicolor. The rationale behind this study is that the increase in the proportional amount of ECMM produced by the organism under a range of different stress conditions, may be explained by the hypothesis of the Hyphal Growth Unit length (HGU). The results presented in this paper support the hypothesis that the length of the HGU is strongly related to the environmental conditions. Cyproconazole at 0.1 mmols l-1 in the growth medium, reduced total biomass by approximately 50% and decreased the length of the HGU by approximately 50%. This change in the HGU length reflects a change in the hyphal behaviour to a highly brached mycelial habit. Associated with this was a 100% increase in the proportion of ECMM in relation to the hyphal biomass. Since ECMM is known to be secreted at the tip of actively growing hyphae, it is hypothesised that by adjusting the length of the HGU, filamentous fungi are able to produce a highly branched mycelium, which leads to the production of high levels of ECMM. This could offer protection against adverse environmental conditions, such as the presence of biocides. These results are discussed with regard to the possible role(s) of ECMM in the decay process and its interaction with preservative treatments.
D Vesentini, D J Dickinson, R J Murphy

Cytoplasmic and extracellular localization of manganese II dependent peroxidase(s) in white rot fungi during degradation of woody materials
1989 - IRG/WP 1416
The manner by which lignin is degraded in-situ in natural substrates by white rot fungi still remains a controversial issue particularly the distribution and role(s) played by lignin degrading enzymes (i.e. manganese II peroxidase and lignin peroxidase). In the present study, use was made of anti-manganese II peroxidase and immunolabelling techniques in conjunction with transmission electron microscopy (TEM) to study the spatial distribution of manganese II peroxidase during degradation of wood and woody fragments by Phanerochaete chrysosporium and Lentinus edodes. Intracellularly, manganese II peroxidase was found localized in the peripheral regions of the fungal cell cytoplasm in association with both the outer cell membrane and membranes within characteristic vesicular bodies. In addition the enzyme was frequently found localized at the interfacial regions of the cell membrane and inner fungal cell wall. Using double immunolabelling procedures and in addition anti-lignin peroxidase, the cytoplasmic distribution of the two lignin degrading enzymes was compared. Both enzymes showed a fairly similar peripheral cytoplasmic localization although manganese II peroxidase tended to be more concentrated compared to lignin peroxidase in peripheral vesicular bodies. Extracellularly, and in solid wood samples manganese II peroxidase was found localized in all wood cell wall regions of either Betula verrucosa, Populus sp. or Fagus sylvatica decayed by either Phanerochaete chrysosporium or Lentinus edodes at both early and late stages of degradation. In particular, manganese II peroxidase was localized in characteristic zones of degradation produced within the secondary wood cell wall regions. These regions displayed a more open structure compared to unattacked wood cell walls and were easily penetrated by lignin degrading enzymes as judged by infiltration and double immunolabelling studies with highly purified and partially purified manganese II and lignin peroxidases. With Lentinus edodes a very characteristic pattern of lignin degradation was noted in which the middle lamella regions between wood cells was selectively degraded. In these regions manganese II peroxidase was found concentrated and associated with its degrading matrix. An extracellular distribution of manganese II peroxidase associated with wood fragments was also observed in liquid cultures of Phanerochaete chrysosporium grown under conditions optimal for peroxidase production. Despite the immersed conditions, similarities between the patterns of attack and extracellular distribution of the enzyme as for solid wood were noted. With both solid wood and wood fragments, manganese II peroxidase penetration was restricted to regions showing structurally modification, and penetration into undecayed cell walls was not observed. The present work suggests a close substrate-enzyme association during wood cell wall and lignin degradation under natural conditions, and in addition, a close correlation between changes in the micromorphology of decay and manganese II peroxidase distribution. Possible reasons for the failure of previous and similar immunolabelling studies to show such a correlation with lignin degrading enzymes are briefly discussed.
G F Daniel, B Pettersson, T Nilsson, J Volc

Investigation of extracellular mucilaginous material in some wood decay fungi
1996 - IRG/WP 96-10188
The external morphology of the extracellular mucilagenous material (ECM) produced by Coriolus versicolor and Coniophora puteana during colonization of Scots pine and beech was studies using SEM. Specimens were examined in the frozen hydrated, freeze-dried and critical point dried state. All technics produced artefacts but the ECM was best preserved when examined the frozen hydated state. Critical point drying damaged the ECM extensively but was useful in partly explaining its nature. ECM was found to line much of the lumen and coated aerial fungal mycelium. Some morphological patterns in which the ECM and fungal hyphae were involved are also descibed.
A R Abu, D J Dickinson, R J Murphy

Extracellular mucilage (ECM) in wood decay basidiomycetes
2002 - IRG/WP 02-10439
The ability of wood decay basidiomycetes to produce extracellular mucilage (ECM) and its relationship with total biomass production is being investigated. Growth and ECM production by the brown-rot fungus Gloeophyllum trabeum (FPRL 108 N) and the white-rot fungus Coriolus versicolor (CTB 863 A) was assessed in liquid culture under different conditions and in the presence of the fungicide cyproconazole. The production of biomass in G. trabeum was significantly influenced by the carbon source, monosaccharides stimulating increased biomass compared with oligosaccharides and polyols. The nitrogen source also significantly affected biomass production, with arginine and L-glutamic acid supporting maximum biomass. The best temperature for growth was 30°C, lower temperature causing a significant reduction in biomass production. The pH optimum for maximum growth was found to be 4.0. ECM production was influenced significantly by the nitrogen source, as well as by the pH of the medium and the temperature of incubation. The greatest proportion of ECM in the total biomass was produced by cultures incubated at 10°C (27% of the total biomass) and at pH 5.0 (16% of the total biomass). The same factors that affected the production of biomass and ECM in G. trabeum, also significantly affected C. versicolor. Again, simple monosaccharides supported the best growth. Amongst the nitrogen sources tested, L-glutamic acid stimulated maximum biomass production (double that of any other nitrogen source tested) whereas the greatest proportion of ECM in the total biomass was produced with arginine and isoleucine as nitrogen sources. The optimal temperature for growth was 22° C, whilst the optimum pH was 5.0. At 10°C the greatest proportion of ECM was produced, which represented about 24% of the total biomass. In terms of pH effects, the greatest proportion of ECM was produced at pH 6.0. The introduction of cyproconazole significantly reduced the amount of biomass produced by both organisms as expected. However, the production of ECM in both species was also affected greatly by the presence of biocide, with the proportion of ECM in the total biomass increasing significantly as the concentration of cyproconazole was raised. The results are discussed with regard to the possible role(s) of ECM in the decay process and its interaction with a specific organic preservative.
D Vesentini, D J Dickinson, R J Murphy

Effects of biocides on the extracellular mucilaginous material (ECMM) produced by two wood rotting basidiomycetes
2003 - IRG/WP 03-10469
Growth and production of extracellular mucilaginous material (ECMM) by the brown-rot fungus Gloeophyllum trabeum (FPRL 108 N) and the white-rot fungus Coriolus versicolor (CTB 863 A) was assessed in liquid culture, supplemented with the biocides CuSO4 and cyproconazole. The production of biomass in G. trabeum was significantly influenced by the concentration of CuSO4 in the medium. When CuSO4 was added at 1.0 mmols l-1, biomass was reduced by approximately 35%. At this concentration, the production of ECMM, both absolute and relative to biomass, was increased. Cyproconazole had a similar effect to that observed for CuSO4, although much lower concentrations of the biocide were required to achieve a similar response. Addition of 0.1 mmols l-1 of cyproconazole to the growth medium caused a decrease of approximately 35% in the amount of biomass produced and a 200% increase in the proportional amount of ECMM produced by the fungus. A similar behaviour was also confirmed for C. versicolor . In this case, higher concentrations of CuSO4 were required in order to achieve the same levels of inhibition observed for G. trabeum. Cyproconazole-supplemented cultures also behaved similarly to G. trabeum. A concentration of cyproconazole of 0.1mmols l-1 caused a reduction of 50% in biomass and a 100% increase in the proportional amount of ECMM produced by this fungus. The presence of biocide also led to qualitative changes in the composition of ECMM. Galactose, xylose and glucose were the main components of the polysaccharide fractions of the ECMM produced by the two species growing on control media. As biocides were introduced, the proportion of galactose in the ECMM increased. This was always associated with a decrease in the proportion of glucose for G. trabeum and with a decrease in the proportion of xylose in the ECMM produced by C. versicolor. The results are discussed with regard to the possible role(s) of ECMM in the decay process and its interaction with preservative treatments.
D Vesentini, D J Dickinson, R J Murphy

Penichroa fasciata (Stephens) (Col. Cerambycidae) a pest in wood materials
1988 - IRG/WP 1365
Penichroa fasciata (Stephens) (Col. Cerambycidae) is found to be a frequent pest occurring in hardwood in storage in Italy. This paper reports the characteristic for identification, biological features, distribution and timber liable to attack.
A Gambetta, E Orlandi.

Summary of development of pile wrappings in Los Angeles Harbour
1987 - IRG/WP 4141
G Horeczko

The influence of crystalline and amorphous cellulose on extracellular hydrogen peroxide production by brown-rot fungi
1991 - IRG/WP 1482
The production of hydrogen peroxide (H2O2) has been suggested to play a key role in the degradation of wood by wood-rotting fungi. The production of extracellular hydrogen peroxide was studied by a quantitative method which detects the oxidation of the 2,2-azinobis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) by H2O2 and horseradish peroxidase (HRP) in liquid culture medium. The carbon sources used were crystalline and amorphous cellulose. Two brown-rotters, Serpula lacrymans and Poria placenta, were able to produce clearly detectable amounts of extracellular hydrogen peroxide in liquid medium which contained crystalline cellulose as carbon source. No detectable H2O2 was produced in conditions where amorphous medium was used as carbon source. This result suggests that the conformational structure of the substrate may induce H2O2 production by brown-rot fungi.
A-C Ritschkoff, L Viikari

The resistance of painting materials and consolidants against wood-destroying insects
1997 - IRG/WP 97-10239
Natural and synthetic adhesives, varnishes, painting materials and consolidants were used in investigations of bioresistance against newly hatched larvae and beetles of Hylotrupes bajulus (L.). Animal glues, casein, drying oils and natural resins such as dammar resin and shellac, were not resistant to attack by these larvae. Similarly, semi- and all-synthetic polymers tested including hydroxypropylcellulose, acrylate and methacrylate compounds, are also subject to attack by newly hatched larvae of the House Longhorn Beetle. In contrast, addition of inorganic pigments provides a significant improvement in bioresistance. This effect is influenced by the thickness and the hardness of the paintlayer. The test with beetles of Hylotrupes bajulus show that the restoration materials which are not resistant against an attack by newly hatched larvae are preferred for the egg depositions by the females.
W Unger, H Fritsche, A Unger

Preliminary results of investigations on screening test of chemical compounds suitable for the preservation of lignocellulosic materials against biodeterioration
1976 - IRG/WP 262
This paper investigates the possibilities of reducing the time needed for the determination of the effectiveness of chemical compounds from the point of view of their eventual application to lignocellulosic materials for preservation against decay and soft-rot.
K Lutomski, S S Neyman

Mycological testing of plywood and board materials. Part 1: Review of information supplied by IRG members
1978 - IRG/WP 284
In December 1975 IRG members were asked for published information, information of current work in progress and views on mycological test methods for board materials. The object was to stimulate discussion and possibly establish a joint research effort within IRG in order to establish a meaningful test with reproducible results.
C R Coggins

Contribution to the testing of wood based board material
1982 - IRG/WP 2176
R G Lea

Extracellular layers of wood decay fungi and copper tolerance
1983 - IRG/WP 1180
Extracellular layers around the hyphae of brown, white and soft rot fungi have been examined using electron microscopy. These layers were isolated for identification. Particular interest was directed towards the extracellular layers of copper-tolerant soft rot fungi.
D M Francis, L E Leightley

Electron microscopic detection and chemical analysis of three-lamellar structures in wood-destroying fungi
1984 - IRG/WP 1240
In the course of transmission electron microscopical investigations of pine wood decay by various brown- and white-rot fungi extracellular three-lamellar structures (TLS) formed by the fungi were found in specimens stained with ruthenium red. These structures occured in the lumen of the wood cell surrounding the hypha at the outermost layer of the fungal cell wall. In the course of the investigations these structures were also detected in fungi cultivated with glucose on a rotary shaker, where they showed forms similar to tubuli and vesicles. The three-lamellar structures formed by the white-rot fungus Sporotrichum pulverulentum, which were contained in the outermost cell wall layer, were isolated by disintegration of the fungal pellet and subsequent digestion of the fungal cell wall by snail enzyme. It was found that these structures are resistant to the enzymatic digestion and are composed of 80 to 90% carbohydrates, mainly consisting of glucose monomeres, 5 to 10% proteins, containing 5 fractions with molecular weights between 30000 and 200000, and finally 5 to 10% lipids which do not contain any phospholipid.
R Foisner, K Messner, H Stachelberger, M Röhr

Information from the COIPM Wood Group. Summary received via Mme Dr Anna Gambetta (Italy)
1987 - IRG/WP 4139
Two co-operative programmes were discussed: 1) The IRG/COIPM co-operative programme on the CCA/CCB wood treatments and 2) The IRG/COIPM co-operative programme for testing the resistance of plastic wrapping for wooden pilings. The following was reported: In the wood treatment programme, beech, pine and alstonia wood samples have been pressure treated with 3 retentions (3%, 6% and 10%) of CCA and CCB and exposed in the sea, to find out if these timbers have selective resistance to attacks by marine borers and fungi. After nearly 8 years of exposure at many different locations it is becoming apparent that both treatments in pine and alstonia provide better protection than both treatments in beech. It is hoped to find out after chemical analysis why this is happening. In the polyolefin tests this plastic material was heat shrunk around small wooden blocks and exposed to borer attack in many different marine environments, and also in some terrestrial environments where termites were present, to determine if the material prevents attack by the borers. At two stations the test is now in its eighth year. So far the polyolefin material is still intact and has not been penetrated by borers. These two programmes are continuing.
J R DePalma

Results on termite resistance of building materials against Coptotermes formosanus by choice test
1998 - IRG/WP 98-10275
Various building materials, included wood species, wooden board materials, thermal insulation materials and fire-protection materials, were tested for grading of termite resistance against Coptotermes formosanus. The dimension of most specimens were 2x2x2cm3. Ten repeats were prepared. The specimens were put between Akamatsu sapwood control specimens on a laboratory cultured mound colony of termite, Coptotermes formosanus. After 1 month of attack to termite, the specimens were removed from the mound colony and cleaned up. Then these final mass were weighed. The grading of termite resistance was initially estimated by mass loss of specimens. This grading was corrected by visual observation. Japanese 3 domestic species, cypress pine, Alaska- ceder, kapur and mahogany were indicated rather high termite resistance. In the case of Siberian red pine and Gmelina, the valued of termite resistance were shown variable. Tropical species plywood, inorganic board and radiata pine MDF, were shown rather high termite resistance. Other board materials were shown rather less termite resistance. Most of commercial soft wood plywood and OSB were very sensible against termite. Most common thermal insulation materials in Japan were estimated very sensitive against termite. In the case of fire protection materials, expanded concrete was rather good against termite but plaster board was very sensible against termite.
K Suzuki, K Hagio

A collaborative test to determine the efficacy of polyurethane coatings on wood samples exposed in the marine environment
1984 - IRG/WP 4113
Aims are: a) to determine the effectiveness of elastomeric polyurethane as a protective coating against marine wood boring animals in a range of tropical and tempreate sites; b) to compare the adhesion of polyurthane coatings on different wood species exposed in seawater; c) to record the severity of attack in failed samples and to identify the causal marine organisms.
R A Eaton

Evaluation of polystyrene as a protective of wood in sea-water
1986 - IRG/WP 4129
A test is described on the biological protection of wood by treatment with polystyrene. The results, obtained in marine trials, after 18 months, show that the treatment with polystyrene is not all that effective in preventing the attack of marine borers.
A Gambetta

Information from COIPM Wood Group
1985 - IRG/WP 4120
During the last COIPM Meeting (which took place in Athens, Greece in September 1984) the Wood Group met and discussed the co-operative work 'Durability in sea-water of wood with plastic wraps and wood treated with polymere'.
A Gambetta

Lignin degradation by wood-degrading fungi
1986 - IRG/WP 1310
The wood-degrading white-rot fungus Phanerochaete chrysosporium, has been the subject of intensive research in recent years and, based upon isolation of the extracelluar enzyme ligninase, major advances have now been made toward elucidating the mechanism by which this fungus degrades lignin. From these developments, a model emerges which could explain the process by which wood-degrading fungi in general, attack lignin.
P J Harvey, H E Schoemaker, J M Palmer

Durability of different heat treated materials from industrial processes in ground contact
2005 - IRG/WP 05-40312
In this study the durability of heat treated wood originating from four different European industrial heat treatment processes in ground contact was examined. The manufacturers of heat treated material were: PLATO Hout B.V./Netherlands, Thermo Wood/Finland, New Option Wood/France and Menz Holz/Germany where Oil-Heat treated Wood (OHT) is produced. All heat treated materials showed significantly increased durability against decay in ground contact compared to untreated Scots pine (Pinus sylvestris L.), independent from the different heat treatment processes. After four years of field testing, heat treated material appears to be not suitable for in ground contact application, since long service life is required. In analogy to the classification of natural durability (EN 350-1, 1994), durability classes in the range from 2 (durable) to 4 (slightly durable) were achieved by the different heat treated materials. This stands in contrast to statements of suppliers, who promote their material as suitable for in ground applications.
C R Welzbacher, A O Rapp

Decay resistance of high performance biocomposites based on chemically modified fibres
1998 - IRG/WP 98-40120
Different partners within the framework of a European research project produced high performance biocomposites aiming at the utilisation of board materials as durable products both in dimensional and biological degrading circumstances. This paper summarises test data, which indicate the potential of board materials produced with modified fibre material. The chemical modifications applied cover a range of technologies, which were selected for scaling up experiments. Acetylation, as well as alternative methods like maleiation, phthalylation, succinylation, oxidation and silylation were investigated. Fibre source, density variation and the use of several types of glues were parameters of the total set-up. Basidiomycete testing was carried out using specific methodology for board materials elaborated in CEN standardisation committees.
V Rijckaert, J Van Acker, M Stevens

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