Your search resulted in 25 documents.
Reaction of osmium tetroxide with a diphenolic compound as a model substance for demethylated lignin
1986 - IRG/WP 1303
By using caffeic acid as a model substance for diphenolic moieties of demethylated lignin it was found that electron dense particles called by the authors "osmiophilic particles" in former papers are reaction products of OsO4 with the model substance. By these products it is possible to indicate the enzymatic demethylation of lignin taking place during wood decay. The appearance of the electron de...
K Messner, E Srebotnik
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
Non-enzymatic Gloeophyllum trabeum decay mechanisms: Further study
2001 - IRG/WP 01-10395
Information will be presented on the mechanisms involved in, and potential application of, non-enzymatic wood decay by brown rot decay fungi. Specifically, the hypothesized role of low molecular weight phenolate derivatives will be discussed in relation to non-enzymatic degradation of wood. The mechanism of binding of iron by cellulose, and binding and reduction of iron by fungal derivatives and m...
B Goodell, J Jellison
Detection of semi-quantitative and qualitative enzymatic activities of blue-stain fungi
2000 - IRG/WP 00-10347
Blue-stain, produced in forests, continues to be a problem in countries of moderate climate. In forestry, in certain geographical areas of Spain, it has been observed that anti-sapstain products have not always been efficient, as their fungicidal effectiveness varies on occasion, depending on the species of wood and microbiota that exist in the region. It is not always easy to identify the species...
M T De Troya, F Llinares, D Muñoz-Mingarro, M J Pozuelo, N Acero, C Rodríguez-Borrajo, A M Navarrete
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 g...
P J Harvey, H E Schoemaker, J M Palmer
Enzyme systems of bacterial isolates from ponded logs - Potentials of pectin and/or starch degradation
2000 - IRG/WP 00-10378
This paper deals with the degradation potentials of wood constituents by the bacterial isolates from ponded logs. The potentials to degrade pectin as a constituent of pit-tori as well as starch existing in ray parenchyma cells in the areas of sap- and transition wood with the isolates were examined. The pectinase activity was investigated by means of the degradation degree of a carrot strip used a...
S Doi, S Ohta
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
An alternative method for the determination of lignocellulolytic enzymatic activities of white rot fungi
1998 - IRG/WP 98-10261
Some lignocellulolytic activities of wood decay fungi can be evaluated in an indirect way through the study of the decolorization that white rot fungi produces in culture media in the presence of dyes. In this assay, ten dyes were selected, which were added in concentrations of 0.00 1% - 0.003% (P/V) to four-day cultures of Trametes versicolor containing 1% of beech sawdust in a basal salt medium...
D Muñoz-Mingarro, F Llinares, F Rubio, M Yuste, C Rodríguez-Borrajo, J Jiménez, M T De Troya
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 sali...
M T De Troya, F Rubio, D Muñoz-Mingarro, F Llinares, C Rodríguez-Borrajo, M Yuste, M J Pozuelo, J I Fernández-Golfín
In situ testing the influence of melamine resins on the enzymatic activity of basidiomycetes
1999 - IRG/WP 99-30194
Waterbased methanol etherificated melamine formaldehyde resins have the potential to increase the resistance of impregnated wood against wood destroying fungi. The mechanism of the increased wood durability is not clear yet. In the present paper the possible interference of melamine resins with wood degrading enzymes of Coniophora puteana and Trametes versicolor was investigated as a possible cont...
D Lukowsky, F Büschelberger, O Schmidt
Effect of wood polymers degradation during heat treatment on extracellular enzymatic activities involved in beech degradation by Trametes versicolor
2008 - IRG/WP 08-40392
Effect of heat treatment on extracellular enzymes involved in wood degradation by Trametes versicolor was investigated. Heat-treated and untreated beech blocks were exposed to T. versicolor on malt agar medium and extracellular enzymatic activities investigated. A strong ABTS oxidizing activity has been detected during the first stage of colonization in both cases, while cellulase activities are m...
S Lekounougou, G Nguila Inari, M Pétrissans, S Dumarçay, J P Jacquot, E Gelhaye, P Gérardin
Aislamiento, identificación y evaluación enzimática de hongos de pudrición de madera de la Región de los Lagos
2008 - IRG/WP 08-10680
So far, systematic investigations have not been developed to determine the fungal diversity associated with wood in Chile. In addition, little is known about the mycoflora capabilities or their enzymatic processes in biotechnology although different research has hinted at the great potential of these microorganisms in various industrial processes. The aim of this work is to isolate, identify and e...
R Ortiz, J Navarrete, C Oviedo, R Blanchette
Chemical mediated depolymerization of cotton cellulose for the understanding of non-enzymatic fungal decay
2010 - IRG/WP 10-10731
Small, low molecular weight non-enzymatic compounds have been linked to the early stages of brown rot decay as the enzymes involved with holocellulose degradation are found to be too large to penetrate the S3 layer of intact wood cells. The most pronounced of these which were analyzed in this study are hydrogen peroxide, iron, and oxalic. The compounds related to the Fenton reaction: the combinati...
A C Steenkjær Hastrup, B Jensen, F Green III
Wood decay enzymatic ability of Fusarium circinatum
2012 - IRG/WP 12-10777
There exists pathogens that attack standing trees of forests, and do not usually thrive once the tree is felled. However, occasionally they can be present in a latent state in the wood and can spread and affect new areas with economic, ecological and social consequences. Fusarium circinatum is a fungus that causes “pitch canker” in pine species, and is considered a quarantine organism within t...
M T Troya, F Llinares, Y Serrano, M Conde
Scanning Transmission X-ray Microscopy as a tool for examining chemical changes in wood cell walls due to enzymatic activity
2014 - IRG/WP 14-20556
As development of techniques for examining enzymatic activity on solid, complex biological materials, is considered to be an important factor in further development of enzyme applications and for understanding the decay of plant materials, this study explores applicability of Scanning Transmission X-ray Microscope (STXM) for determining chemical changes in enzymatically treated samples at the cell...
D Jeremic, R Goacher, R Yan, C Karunakaran, E R Master
Possible targets of wood modification in brown rot degradation
2014 - IRG/WP 14-40676
Wood modification protects wood from fungal degradation in a non-toxic manner. However, the mechanisms behind the decay resistance in modified wood are currently unknown. The aim of this study was to discuss the i) colonisation, ii) nutrient recognition, iii) transcription, iv) depolymerisation and v) hydrolysis steps in the brown rot degradation progress and explore whether they are inhibited by ...
R Ringman, A Pilgård, G Alfredsen, B Goodell, K Richter
A novel enzymatic treatment as a new approach for wood protection
2015 - IRG/WP 15-40701
Wood durability is a worldwide concern and most treatments tend to fail with regard to their efficacy along the time. Weather conditions lead to a loss of the treatment substances into the surrounding environment and, in consequence, generate also a public health concern. Recently, the employment of oxidative enzymes, such as laccases, has been proposed as a tool for lignocellulosics modificatio...
C Fernández-Costas, S Palanti, M Ángeles Sanromán, D Moldes
Foundation piles: analysis of beech wood decay in service life conditions
2016 - IRG/WP 16-10858
Wood piles foundation system was largely used over decades. Thus, numerous buildings over the world are based on this constructive system. In the context of reduction of CO2 emissions in the building field of constructions, substitution of concrete by wood as material for foundation piles seems to be a promising alternative. However, fluctuation of the water table level in soil may promote fungal ...
Q Kleindienst, A Besserer, M-L Antoine, C Perrin, J-F Bocquet, L Bléron
Wood properties modification by an enzymatic assisted treatment with phenolic extractives
2016 - IRG/WP 16-30696
Extractives of sawdust and bark from P. pinaster and, condensed tannins (CTs) from P. radiata bark were used to treat beech and pine veneers in combination with an oxidative enzyme, in order to stably graft such extractives onto the veneers. First, the antifungal activity of P. pinaster phenolic extractives against wood decay fungi was studied. These extractives were also used to hydrophobize pi...
D Filgueira, C Fernández-Costas, D E García, D Moldes
Investigation of enzymatic effect on pit membranes by light and scanning electron microscopy
2016 - IRG/WP 16-40721
Spruce wood, one of the refractory wood species has pit membranes, which has an influence on the permeability of wood providing liquid flow between the wood cells. However, these membranes tend to close under the fiber saturated point (FSD), which makes impregnation more difficult. In this study spruce sapwood samples were treated with two different commercial enzymes to improve the permeability o...
S Durmaz, Ü C Yildiz, M Öztürk, B Serdar
New perspectives for wood protection: enzyme-based treatments
2016 - IRG/WP 16-40742
Wood protection research is continuously looking for more benign and effective treatments. One of the main concerns deals with the toxicity of the active compounds employed in the formulations of the preservatives, since they could become a health and environmental issue. Secondly, long-lasting treatments are preferred in order to increase the service life of the treated wood. Weathering condition...
C Fernández-Costas, S Palanti, M Á Sanromán, D Moldes
Enhancing Our Understanding of Brown Rot Mechanisms through Catalytic Pretreatment and Cellulase Cocktail
2018 - IRG/WP 18-10909
A catalytic mechanism, described as the “chelator-mediated Fenton” (CMF) mechanism, is proposed to mimic the non-enzymatic action of brown rot fungi. A CMF treatment was used together with an enzymatic cocktail to study how wood was deconstructed and solubilized. This was done in-part to determine if the treatment mimicked the action of brown rot fungi, but also to explore improved treatment p...
S Tabor, L Orjuela, D Contreras, G Alfredsen, J Jellison, S Renneckar, B Goodell
Different levels of acetylation lead to groupwise upregulation of non-enzymatic wood degradation genes of Rhodonia placenta during initial brown-rot decay
2020 - IRG/WP 20-10958
Rhodonia placenta, often used as a model fungus to represent brown rot fungi, uses a two-stepped degradation mechanism to degrade wood. Regarding the overcoming of wood protection systems the initial degradation phase seems to be the crucial point. A new laboratory test enables the separation of the non-enzymatic oxidative and the enzymatic degradation phases, which has previously been proven chal...
M Kölle, R Ringman, A Pilgård
Effect of enzymatic inhibitors on the population of Reticulitermes grassei and their associated microbiota
2023 - IRG/WP 23-11008
Termites are pests that invade urban, agricultural and forest environments worldwide. They are economically important owing to the damage they cause to wood, wood products, building materials, agricultural products and forests. There are many methods for its control, but many of them cause negative environmental effects due to their toxicity. In termites, dietary change or antibiotic treatment may...
S M Santos, M T Troya, F Llinares, P Colina, E García, M Álvarez, L Robertson
Isolation of the microbiota from wood decay insects and some of their enzymatic activities
2023 - IRG/WP 23-11014
Wood decay organisms have the ability to degrade wood components (cellulose, hemicellulose and lignin) by enzymatic capacities, but these enzymes can belong to the proper organism, or to the associated microbiota. The identification of the microorganisms, as well as their role in the digestion of many substrates not always is very well known. The wood decay insects produce big damages in wood str...
M T Troya, F Llinares, J Arranz, S Izpura-Luis, S M Santos, L Robertson