Your search resulted in 13 documents.
A discussion of current theories concerning CCA fixation
1983 - IRG/WP 3238
The understanding of the fixation mechanism of CCA and related preservatives in wood has been greatly improved by a significant series of recent scientific papers. In view of recent concerns in New Zealand regarding the long-term efficacy of CCA in high decay-hazard situations, it was considered appropriate to review this recent work and to contrast it with theories presented by previous workers.
D V Plackett
Characterisation of growth and stain of different groups of sapstain fungi on lodgepole pine
1999 - IRG/WP 99-10326
Canada is the world's largest exporter of softwood lumber. These softwood shipments are susceptible to a variety of wood-inhabiting fungi that can lead to sapstain discolouration, which in turn decrease the product value. Furthermore, the presence of these microorganisms may be unacceptable to the importing countries. The objective of this work is to assess the sapstaining capability and basic nutrition of thirty-four fungi isolates representing nine species that were isolated from sawmills across western Canada. The isolates were infected onto fresh lodgepole pine billets and assessed for staining ability, longitudinal growth, host-nutrient consumption, and host viability. The results indicated that the most aggressive saptain species on fresh logs was Ceratocystis coerulescens, followed consecutively by Leptographium spp, Ophiostoma minus, O. piliferum, O. piceae, Ophiostoma spp (D and E) and Aureobasidium pullulans. Preliminary HPLC analysis of soluble sugars indicated that mannose was the free monomer carbohydrate of choice for most of the staining fungi, followed by glucose. Arabinose and galactose were not well utilised. Gas chromatography of infected wood extracts that Leptographium sp. and C. coerulescens significantly reduced the triglyceride fraction.
C Fleet, C Breuil, A Uzunovic, A Byrne
The potential of 2-deoxy-D-glucose as an active ingredient in wood preservation
1999 - IRG/WP 99-30205
2-deoxy-D-glucose (2-DOG) is a potential active ingredient against wood decaying fungi. When dissolved in water, it can be used in pressure treatment of wood. Thereby the wood is protected from attack by wood decaying fungi. A concentration of 1.5% (mean retention 9.7 kg/cubic meter sap-wood) is adequate for brown rot fungi, and 3% (mean retention 19.5 kg/cubic meter sapwood) will also provide protection against white rot fungi. 2-DOG is easily soluble in water, and is therefore easily leached from the wood upon completion of the preservation process. Different types of fixa-tion methods have been tried and evaluated. It is possible to produce 2-DOG by the hydrolysis of chitin, a constituent of the exterior skeleton of shellfish and insects. There is a potential for exploita-tion of this waste product provided by the crab and shrimp industry. The yield of 1 kg of fresh shrimp is 75 g of 2-DOG.
O V Frederiksen, A P Koch
Conditions for basidiospore production in the brown rot fungus Gloeophyllum separium in axenic culture
1984 - IRG/WP 1232
Attempts to control and optimize the production of hymenial structures and basidiospore production in Gloeophyllum sepiarium in axenic culture resulted in the proposal of the following conditions as being suitable. The dikaryotic mycelia originally isolated from basidiocarps could consistently be induced to produce hymenial structures and pure basidiospore collects if illuminated by near ultraviolet light with emission maximum at 355 nm ("black light") at a temperature of 15°C on a chemically defined medium, where the concentration of the carbon and the nitrogen sources were shown to be of critical significance. The necessary conditions for basidiospore production in lignicolous fungi in general are is briefly discussed.
1983 - IRG/WP 3268
Distribution of cellulases in the body of Coptotermes formosanus and the probability that the termite uses glucose as an energy and carbon sources
1997 - IRG/WP 97-10202
We assayed extracts of the digestive system and of the whole body of Coptotermes formosanus to determine where the various cellulases, glucose, and related substances were concentrated and to detect pyruvate dehydrogenase activity in the hindgut-removed body in order to verify its full cellulolytic system. About 20%, 18% and 36% of the total exo-1,4-ß-glucanase activity of C. formosanus were detected in the salivary glands, midgut, and hindgut, respectively. About a third of the total endo-1,4-ß-glucanase activity in the termite was detected in the salivary glands (34.5%) whereas the activities in the midgut and hindgut were 21.1% and 18.2%, respectively. About 75% of the total ß-D-glucosidase activity in the termite was detected in the midgut. Thus all the necessary cellulases for hydrolysis of natural cellulose to glucose were present in the region ranging from the salivary glands to the midgut in significant amounts. Most of the glucose and trehalose detected in the termite existed in the gutted-body. Most of the glucose detected in the gut existed in the midgut. Pyruvic acid was directly converted to acetyl-CoA in the presence of NAD+ by a crude extract of the gutted-body. These results suggest that natural cellulose ingested by the termite is hydrolyzed to oligosaccharides in the region of the foregut and midgut as well as in the hindgut, that oligosaccharides are hydrolyzed to glucose predominantly in the midgut, and that the resultant glucose is absorbed through the midgut wall into the tissues to be used as important energy and carbon sources.
S Itakura, H Tanaka, A Enoki
Biosynthesis of ß-Glucan microfibrils by cellular fractions from brown-rot fungus Postia placenta (MAD-698 and ME-20) and white-rot fungus Schizophyllum commune (MAD-619)
1993 - IRG/WP 93-10025
In this study, we compared the brown rot fungus Postia placenta (MAD-698 and ME-20) with the white rot fungus Schizophyllum commune (MAD-619) to determine the location and distribution of glucan synthetase. We also measured the soluble protein content in subcellular fractions obtained by differential centrifugation MAD-698 is a degradative isolate, but ME-20 and MAD-619 do not produce significant weight loss in wood. The solubilized enzyme glucan synthetase catalyzes the UDP [U-l4C] glucose to synthesize an insoluble linear 1,3-ß-D-glucan polymer. Glucan is a component of basidiomycete cell walls and hyphal sheath. The wood-degrader MAD-698 showed the most glucan synthetase activity in the mixed membrane fractions, and the nondegradative isolates ME-20 and MAD-619 had the most activity in the cytoplasmic fractions. In fact, glucan synthetase activity was found in different proportions in different particulate fractions of MAD-698, ME-20, and MAD-619. Treatment with a mixture of the detergents octylglucoside and CHAPS ( 3 -[(3-Cholamidopropyl)-dimethylammonio]-1-propane-sulfonate) increased the glucan synthetase activity only in the cell wall fraction.
S C Croan, T L Highley
Analysis of D-glucose metabolism of wood decay fungi using 13C-NMR and 13C-labeled substrates
2003 - IRG/WP 03-10475
D-Glucose metabolism is thought to be important during wood decay by fungi, not only for anabolic and catabolic purposes of central metabolism, but also as a potential source of peroxide required by extracellular peroxidases. There has been some confusion in the literature as to whether this peroxide-generating activity is of the glucose 1-oxidase or pyranose 2-oxidase (glucose 2-oxidase) type with various fungi or even within the same fungal species. Definitive classification requires accurate identification of the enzymatic products D-glucono-1,5-lactone and D-arabino-2-hexosulose (glucosone) with glucose 1-oxidase and pyranose 2-oxidase, respectively. We used 13C-NMR to distinguish these reactions starting with 13C-labeled glucose. The use of labeled substrates simplifies analysis and greatly increases detection sensitivity without requiring the isolation or derivatization of metabolites. We synthesized 13C-1-glucosone to study subsequent metabolism with crude enzyme preparations. Preliminary results with Phanerochaete chrysosporium are presented.
T H de Koker, M D Mozuch, P J Kersten
Basisiospore production by Lentinus lepideus in vitro
1987 - IRG/WP 2276
Evaluation of fungicides active against the lower fungi by spore based bioassays is very common. Possibilities of using similar assays to evaluate preservatives against brown rot and white rot fungi, especially for use in above ground constructions, are limited by the lack of methods for production of basidiospores. Tested media containing glucose 10-30 g/l and ammonium tartrate concentrations 2-20 g/l supported fairly good spore production. Media buffered with the organic buffer 2 (N-morpholino) ethane sulfonate (MES) with phosphate concentrations of 12.5-50 mM supported good spore production.
Fruitbody formation and basidiosporogenesis by the white rot fungus Pycnoporus cinnabarinus
1988 - IRG/WP 1348
Conditions for fruitbody formation by the white rot fungus Pycnoporus cinnabarinus in vitro were outlined. A marked difference in substrate requirements in comparison to previously tested brown rot fungi was revealed. Agar media containing Walseth cellulose and NH4 tartrate at 1 g/l permit profound production of basidiospores particularly at 15°C but only under light treatment. Higher NH4 tartrate concentrations and glucose addition slowed down or inhibited the fruitbody formation. Axenic basidiospores, to be used in tests for inhibitors contributing to natural durability, as well as in tests for fungicides could thus be produced.
Enzymatic study of Ceratocystis sp., blue-stain fungi on Pinus nigra
1999 - IRG/WP 99-10315
One of the main problems that the forest exploitation industry has with Pinus nigra wood is the blue-stain fungi, whose causing agent is unknown. Therefore, the objective of this work has been to study, through enzymatic tests of the isolated cultures, if these fungi infect Pinus nigra in any specific way. After the incubations, isolates of Ceratocystis were obtained. These were cultured in a saline medium with sawdust of Pinus nigra and Pinus sylvestris, which were used as reference species. At different incubation times, carboxymethylcellulase, xylanase, cellobiohydrolase, laccase and manganese peroxidase were determinated. The results obtained show that the cellulolytic enzymes and laccase have higher activity on Pinus nigra sawdust than on Scots pine, while the Mn peroxidase showed higher values on the sawdust of the latter. Likewise, the cultures were developed in the same saline base medium with different monosacarides (glucose, galactose, mannose, xylose and arabinose), and in determining the residual sugar content, a marked prefrence for the consumption of pentoses in respect to the glucose was observed. The enzymatic activity tests carried out by APY ZYM also showed qualitative and semiquantitative differences between the isolated fungi and other Ceratocystis species tested, so, in addition to the above results, this could indicate a certain specificity of these fungi for this wood species.
M T De Troya, F Rubio, D Muñoz-Mingarro, F Llinares, C Rodríguez-Borrajo, M Yuste, M J Pozuelo, J I Fernández-Golfín
Fungal detoxification of organotin biocides
1985 - IRG/WP 1258
The ability of a range of wood decaying fungi to inactivate bis(tri-n-butyltin) oxide (TnBTO) in the extracellular growth medium, in stationary liquid culture was determined. A distinction between the ability to tolerate the fungicide and to inactivate it was made: the white-rot organism Coriolus versicolor being the most efficient inactivator. In an attempt to determine the extracellular agents responsible for any detoxification, Coriolus versicolor was shown to produce significantly greater levels of extracellular free radicals/peroxidase. Preliminary tests have shown the nature of the associated anion on the fungicide effects the susceptibility of tributyltin compounds to free radical attack in a chemical system. The ability of an free radical scavenger to reduce detoxification in such a system has also been demonstrated.
P S Belford, D J Dickinson
Non-structural carbohydrates mobilization throughout the stem of Tectona grandis: A strategy for enhancing the wood natural durability
2010 - IRG/WP 10-10729
Non-structural carbohydrates (NSC) storage is an important feature of heartwood substances formation. Radial distributions of NSC before and after chemical (acid and basic) hydrolysis, were quantified using a spectrophotometric method after enzymatic reaction and the corresponding macromolecules of conjugated NSC analyzed by HPLC, were studied in teak stem with reference to wood in environmental condition. In sapwood, free NSC (starch, glucose, fructose and sucrose) content and that of conjugated NSC (glucose) decreased abruptly from sapwood to heartwood. In both sapwood and heartwood, NSC were bounded to two unidentified compounds HB1 and HB2 which were well-characterized by high performance liquid chromatography (HPLC)/diode array detector. Our results show that free (70%) and conjugated (30%) NCS mobilized in sapwood, underwent high catabolic activities in the transition zone leading to their drastic depletion in heartwood. In heartwood unmetabolized glucose was stored by glucosilation with HB1 and HB2 and probably with other molecules. These results indicate that NSC mobilization throughout the stem could be a strategy for long lasting species like teak with consequences on decay resistance of wood.
B F Niamké, N Amusant, D Stien, A Amissa Adima, C Jay-Allemand