Your search resulted in 219 documents. Displaying 25 entries per page.
Evidence for the participation of the osmiophilic particles in the enzymatic demethylation of lignin
1984 - IRG/WP 1239
Transmission electron microscopic observations of the white-rot fungi Trametes hirsuta and Phanerochaete chrysosporium grown on a series of wood pulp with a graded lignin content and mycelium from the clarified centre of an agar-medium containing lignin (E1-effluent from the bleaching process) showed that osmiophilic particles are only induced by native lignin. Taking into account that the osmioph...
K Messner, H Stachelberger
Degradation of lignin model compounds with coordinated copper in the presence of peroxide
1998 - IRG/WP 98-10282
A novel diffusible system capable of decomposing lignin model compounds with copper, coordinators and peroxides has been proposed. When pyridine was used as a copper coordinator, two synthetic dyes, Poly-R and RBBR were intensively decolorized with Cu(II) and H2O2 in aqueous solutions at room temperature. Although reactions with Cu(II) and H2O2 produce a strong oxidant, hydroxyl radical, via a Fen...
K Koller, K Messner, T Watanabe
Preservative ability of wood to be fixed hydroxyl apatite substituted for antimicrobial metals
2001 - IRG/WP 01-30272
We succeeded in forming hydroxy apatite (HAp) in wood. HAp is non-toxicity and safe. Preservative ability of the wood, which substituted one part of Ca of constituent element of this HA p for antibacterial metals was measured. When Ca was substituted for Ag or Zn, mass loss in decay by brown-rot fungus F. palustris was restrained in about 50% (Ag) ~30% (Zn) of value of control specimen. However, w...
Y Haruhiko, I Sumaru
Studies on the resistance of DMDHEU treated wood against white-rot and brown-rot fungi
2005 - IRG/WP 05-10566
Beech wood (Fagus sylvatica) modified with the textile finishing agent 1,3 dimethylol-4,5-dihydroxyethylen urea (DMDHEU) has shown to improve durability against the white-rot fungus Trametes versicolor. In a mini-block test, the weight loss over eight weeks of incubation decreased with increasing weight percent gain (WPG) of DMDHEU. At 25% WPG, no significant weight loss was observed, while untrea...
P Verma, C Mai, A Krause, H Militz
Influence of CCA and TnBTO on wood decay, under different oxygen levels and various initial moisture content
2001 - IRG/WP 01-10415
Fagus sylvatica (beech) and Pinus sylvestris (Scots pine) were impregnated by TnBTO (tributyl-tin oxide) and CCA (chromated copper arsenate). In wood blocks two levels of moisture content (50% and 100% of saturation point) were used. Three levels of oxygen concentrations (10, 21, and 50%) were chosen. Treated and untreated wood were exposed to three fungi (C. versicolor a white rot, C. puteana, a ...
S M Kazemi, R J Murphy, D J Dickinson
Extracellular hydrogen peroxide producing and hydrogen peroxide reducing compounds of wood decay fungi
1991 - IRG/WP 1516
Extracellular H2O2-producing and H2O2-reducing compounds were isolated from wood-containing cultures of all the white-rot and brown-rot fungi and Ascomycetes which well degraded wood, but were not detected in the culture of the fungi which degraded little wood. The compounds are glycopeptides with a low molecular weight, require H2O2 for one-electron oxidation, catalyze the redox reaction between ...
A Enoki, G Fuse, H Tanaka
Control of sapwood-inhabiting fungi by fractionated extracellular metabolites from Coniophora puteana
1991 - IRG/WP 1494
The objective of this study was to test the fractionated metabolites released by Coniophora puteana for their antagonistic activity against the sapstain fungi Ceratocystis coerulescens and Aureobasidum pullulans, and the molds Asperigillus niger and Penicillium spp. The acetone-soluble fraction obtained from the culture filtrate prepared from Coniophora puteana grown on 6% malt extract agar inhibi...
S C Croan, T L Highley
Lignin degradation by a non-enzymatic system supposed to be active in white rot fungi
2000 - IRG/WP 00-10340
Electron microscopic investigations have shown that ligninolytic enzymes of white-rot fungi are only able to penetrate the wood cell wall in late stages of degradation. Thus, the selective degradation of lignin of certain white-rot fungi can only be explained on the basis of a low molecular weight, highly diffusible system. A system, consisting of copper, a coordination compound and either H2O2 or...
P Lamaipis, W Gindl, T Watanabe, K Messner
Cellular and fractural failure after supercritical fluid impregnation of four wood species
2004 - IRG/WP 04-10503
Supercritical fluids (SCFs) have been investigated for delivering biocides into sawn wood. Pressure differentials during treatment may exceed the compressive or tensile strength perpendicular to grain, creating a potential for transverse deformations that exceed elastic strain limits. Wood treated by SCF processing with CO2, a potential biocide carrier, was inspected macroscopically and microscopi...
M E Anderson, R J Leichti, J J Morrell
Trials of new treatments for prevention of kiln brownstain of white pine (Pinus strobus)
1995 - IRG/WP 95-30068
White pine (Pinus strobus) often develops a surface brown oxidative stain when kiln dried. Such stain downgrades high quality lumber and is most likely to occur when fresh, unseasoned lumber is stacked during warm weather prior to kiln drying. Use of reducing agents or pH alteration has been successful, but may have some practical limitations for general use. This study attempted to prevent browns...
E L Schmidt, E Christopherson, T L Highley, M H Freeman
Decay resistance of Platanus acerifolia wood against White Rot Fungi (Coriolus versicolor)
2002 - IRG/WP 02-10431
Degradation of the lignocellulose complex in wood varies on the microorganism causing decay and chemical composition of wood. The weight loss of Platanus acerifolia wood after decay by white rot fungus (Coriolus versicolor) for period 16 weeks were evaluated according to European standard EN 113 and beech wood as a control. The samples were collected in October 2000 from Nantes, France. The aim of...
M Irmouli, O Duchelier, N Ayadi, B Charrier
Secretion of ligninolytic enzymes by hyphal autolysis of the white rot fungus Phanerochaete chrysosporium
1991 - IRG/WP 1480
The secretion of ligninases by Phanerochaete chrysosporium was investigated with polyclonal antibodies, followed by immmunogold-silver staining and light microscopy. After growing fungal mycelium on nitrocellulose, extracellular ligninases were detected around old, plasmaless hyphae, but not at arthrospores, chlamydospores, or blastoconidia. Labeling of fungal hyphae on coverslip cultures was obse...
R Lackner, E Srebotnik, K Messner
Micromorphology of Schizophyllum commune attack in pine (Pinus sylvestris) wood
1983 - IRG/WP 1184
The decay pattern caused by Schizophyllum commune in pine latewood tracheids was studied using both light and transmission electron microscopy. The attack began as isolated concentric slits within the S2 layer with extensive lamellation and separation of individual wall layers observed in subsequent stages of decay. The slits resulting from attack appeared to be formed in thin, regular concentric ...
T Nilsson, G F Daniel
Supercritical fluid treatment: Effects on bending strength of white spruce heartwood
1993 - IRG/WP 93-20008
The effects of supercritical carbon dioxide on wood strength were evaluated using white spruce heartwood, a species known to be especially susceptible to collapse during exposure to higher pressures. The effects of pressures of 2000 or 3600 psig and temperatures of 40 or 80°C were evaluated using 30 or 60 minute exposure periods. No significant differences were noted in modulus of rupture or modu...
S M Smith, J J Morrell, E Sahle-Demessie, K L Levien
Fungal colonisation of the keelson and associated structures of a nineteenth century wooden frigate: Concepts of community structure and development
1994 - IRG/WP 94-10072
The early stages of microbial colonization and succession of wooden surfaces exposed to the sea have been extensively studied as have the community structures of archaeological timbers subjected to submergence and then retrieval from the sea. The frigate UNICORN, a largely intact 19th century wooden ship based in Dundee, Scotland, provides the microbial ecologist with a unique opportunity to study...
N A White, J W Palfreyman, G M Smith
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...
D Vesentini, D J Dickinson, R J Murphy
Utilization of coconut timber from north Sulawesi, Indonesia. Part 1: Durability
1994 - IRG/WP 94-30044
Coconut timber from non-productive plantations is a byproduct of an agricultural crop and, by the same token, constitutes a renewable resource which may serve as a complement to or, at least in part, as a substitute for traditional timbers in local markets. Its more extensive utilization is expected to contribute to the conservation of tropical rain forests. Export of coconut timber and/or wood pr...
R-D Peek
Kerfing reduces checking in ACA-treated western white spruce poles
1988 - IRG/WP 3477
Western white spruce poles, pressure treated with pentachlorophenol and ammoniacal copper arsenate (ACA) were installed in the Westham Island test site. The pentachlorophenol treated poles were unkerfed, while both unkerfed and kerfed ACA poles were placed in test. The checking and kerf width and depth were recorded at the time of installation. After ten years of weathering the checking characteri...
J N R Ruddick
Extracellular substance from the white rot basidiomycete Irpex lacteus involved in wood degradation
1992 - IRG/WP 92-1571
Cellulases, phenol oxidase, and a substance that both produced and reduced H2O2 were isolated from cultures containing wood or glucose on which the white-rot fungus Irpex lacteus was growing. The rate of wood degradation by the fungus with different amounts of glucose in the medium was measured. More of the substance that produced and reduced H2O2 was found extracellularly in cultures containing w...
H Tanaka, T Hirano, G Fuse, A Enoki
Lab and field test results for wood treated with polymeric alkylphenol polysulfide
2001 - IRG/WP 01-30268
A new wood preservative based on polymeric alkyphenol polysulfide (PXTS-A) is being evaluated in a series of laboratory and field tests and the results continue to show promise. A modified formulation (PXTS-B), which contains additives to reduce the viscosity, is being evaluated along with the original formulation. Soil block decay tests comparing PXTS-B with CCA-C indicate that PXTS-B is equally ...
J Goswami, A Abramson, R Buff, D D Nicholas, T Schultz
Durability aspects of (hydro)thermal treated wood
2000 - IRG/WP 00-40160
Samples of several wood species were treated in a two steps process, subsequently hydrothermal and dry heat-treated, by the so-called PLATO-process and analysed for their resistance against fungal attack. Both PLATO-treated and dry heat-treated specimen were prepared and analysed, in order to study the influence of moisture during hydrothermal treatment of wood. The resistance against all of the s...
B F Tjeerdsma, M Stevens, H Militz
Relative merits of laboratory and field tests for assessing wood decay resistance
1993 - IRG/WP 93-20009
Laboratory and field trials have long been employed for assessing natural durability of a variety of wood species, but there is a continuing debate concerning the relative merits of approach. While laboratory tests provide carefully controlled conditions for decay, they are often criticized for being too artificial to produce meaningful results. Conversely, field trials often vary widely between t...
T C Scheffer, J J Morrell
Determination methods of phytotoxic effect of wood preservatives
1990 - IRG/WP 2349
The phytotoxic effect of wood preservatives so widely used plays a considerable role in the protection of natural environment. A review was made of the existing methods with which to assess the phytotoxicity of the above chemicals and some suggestions were given concerning the methods most appropriate for their unification. Two areas of research are proposed: 1) estimating the direct effect on ind...
A Kundzewicz, J Wazny
Sampling and analysis of NeXgen-treated timber
1998 - IRG/WP 98-20134
Green sawn timber surfaces of the softwood Caribbean pine and the hardwood white cheesewood were treated by dipping, spraying, and precise spiking with the antisapstain product NeXgen. After storing for either two hours or two weeks, the treated surfaces were sampled by one of four alternative protocols, which included two involving a square wad sampling punch (one hit or six hits), one involving ...
M J Kennedy, D E Ferlazzo, T L Woods, M H Freeman
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 micro...
G F Daniel, B Pettersson, T Nilsson, J Volc