Your search resulted in 314 documents. Displaying 25 entries per page.
Physiological properties of fungal test strains according to the European Standard EN 113
1986 - IRG/WP 2258
For the discussion of the European standard EN 113 the EMPA's procedure of culturing the test fungi and the corresponding virulence of the test fungi as well as the wood moisture content at the end of the test are shown. It is mainly shown that within the standard the choice of the solvent may not be left at the test lab if reproducible results shall be obtained. The different solvents influence in different form the wood decomposition values due to fungal attack. A water leaching of the wood specimen impregnated with solvents generally Further increases the negative effect of the solvent on the fungi. It is therefore the task of the Technical Committee of the European Committee for Standardization (CEN/TC3B) to agree to a standard solvent and to evaluate this in the original state as well as after a leaching followed by uniform drying periods by means of an interlaboratory test.
E Graf, B Zgraggen, P Manser
A comparison of fungal strains used in the bioassay of wood preservatives
1984 - IRG/WP 2220
Previously published data are presented relating to a number of strains of wood-destroying basidiomycetes (Coniophora puteana, Coriolus versicolor, Gloeophyllum abietinum, Gloeophyllum sepiarium, Gloeophyllum trabeum, Lentinus lepideus, Poria placenta, Fibroporia vaillantii and Serpula lacrymans) commonly used as test fungi in the bioassay of wood preservatives. The data, which has not been statistically compared, consists of mycelial growth rates, decay capacities, and toxic values using agar, agar-block and soilblock methods based on data published over a period of almost 50-years. In many cases a large variation can be observed between strains originating from the same geographical region and between strains from different climatic-geographical zones. The differences between individual sub-cultures of the same strain, as used in various laboratories - or even in the same laboratories - are noted. Many of the published bioassay methods contain insufficient detail to make statistical assessments. Therefore, the authors have not attempted a definitive comparison of the numerous data. A proposal is presented to organize an international resource of pure cultural strains used as test organisms in bioassays of wood fungus may be dictated by local requirements.
J Wazny, H Greaves
Screening of fungal strains for wood extractive degradation
1998 - IRG/WP 98-10254
Fungal strains were screened for their ability to degrade apolar extractives in wood from scots pine. The degradation of total wood extractives by 91 different strains was monitored in stationary batch assays incubated for 6 weeks. The results obtained show that the ability of wood-inhabiting fungi to utilize wood extractives varied greatly, even for different isolates of the same species. Fungal pretreatment provided up to 70% total resin reduction. Outstanding strains included mainly white-rot fungi. Several sapstain strains were also efficient extractive degraders. Apolar extractives are well known for their inhibitory effect to fungal growth. However, our findings show that wood extractives can serve as carbon source for numerous wood-inhabiting fungi. Furthermore, these results indicate the potentials of wood-inhabiting fungi in biotechnological processes for pulp and paper manufacturing, ie., wood chip depitching and biodetoxification.
J Dorado, M J Martinez-Inigo, T A van Beek, F W Claassen, J B P A Wijnberg, R Sierra-Alvarez
The Impact of Cryopreservation Techniques and of Water Quality on the Wood Degrading Ability of Fungal Strains: Recommendations for Maintenance and Culturing Procedures
2018 - IRG/WP 18-20636
In order to establish an optimal cryopreservation method, strains of Basidiomycete and Ascomycete fungi, which are among the most frequently used for wood durability testing, were evaluated using three cryopreservation procedures at -80°C. The main objective was to prevent decrease of the fungal virulence that may occur due to repeated routine sub-culturing procedures and to optimize the reactivation percentage of the strains, which is a particularly challenging issue in the case of Basidiomycetes fungi. In addition, the influence of the quality of water used for the preparation of the culturing malt agar medium on the mycelium growth and on the virulence of fungal strains was assessed. The vitality of all fungi was successfully preserved with cryopreservation at -80 °C during six months in sterile water with 25% or 50% of glycerol used as cryoprotectant. These two cryopreservation techniques negatively influenced the wood degrading ability of five Basidiomycete strains (out of the nine studied) that were tested for virulence after reactivation. Our findings suggest that the tested cryopreservation protocols are not suitable for long-term preservation of all Basidiomycetes species involved in standardized durability testing. However, they were found suitable for the tested strains of Rhodonia placenta, Coniophora olivacea and Trametes versicolor, which are commonly used in standardized efficacy tests. No general pattern was found regarding the optimal type of water, among the three types tested, used for the preparation of the fungal culture medium. The growth rates and virulence measured by mass loss of small-size wooden blocks varied between the strains exposed to the same culturing conditions. These results demonstrate the importance of species-specific optimization of laboratory culture conditions and maintenance procedures with regard to the fungal strains used.
A Stum, M Montibus, I le Bayon, M Kutnik
Questionnaire - Fungal decay types
1985 - IRG/WP 1265
Improvements of monitoring the effects of soil organisms on wood in fungal cellar tests
1996 - IRG/WP 96-20093
Accelerated testing the durability of preservative treated timber in a so called "fungal cellar" or "soil-bed" to evaluate its performance in ground contact is widespread practice. In order to obtain a more accurate and reproducible estimate of preservative performance, several institutes, among them the BAM in Berlin, have routinely carried out static bending tests in addition to visual examination. These tests were usually performed with a defined maximum load or deflection path regardless of the remaining degree of elasticity of the test specimens. Recent studies at the BAM revealed that by modifying the method, i.e. by restricting the applied load to the non-destructive interval for each individual test specimen, the calculated modulus of elasticity (MOE) reflect the changing strength properties caused by biological deterioration and allow within a relatively short time valuable predictions on the service life of the treated timber in soil contact.
I Stephan, S Göller, D Rudolph
The restricted distribution of Serpula lacrymans in Australian buildings
1989 - IRG/WP 1382
Temperature data has been gathered over a number of years, not only for flooring regions of various buildings in Melbourne, but also within roof spaces and external to the buildings. Findings are discussed in relation to the distribution of Serpula lacrymans within Australia, its restriction to certain types of building construction and its restriction to flooring regions. The subfloor spaces of badly-ventilated, masonry buildings are highlighted as being better suited than are the subfloor spaces of, for example, Japanese buildings for the activity of this fungus. Hence Serpula lacrymans is very restricted in its distribution in Australia, yet where it is active it does grow rapidly and causes rapid flooring failures.
J D Thornton
Fungal and bacterial attack of CCA-treated Pinus radiata timbers from a water-cooling tower
1991 - IRG/WP 1488
Transmission electron microscopy of decaying CCA-treated Pinus radiata timbers from an industrial water cooling tower showed presence of a thick biofilm covering some areas of the wood. The biofilm contained various morphologically distinct forms of microorganisms embedded in a slime. The study provided evidence of the activity of soft rot fungi and tunnelling and erosion bacteria in wood cells. The extent of damage to wood cells due to microbial activity varied, combined fungal and bacterial attack having the most damaging impact.
A P Singh, M E Hedley, D R Page, C S Han, K Atisongkroh
Monographic information on Schizophyllum commune
1975 - IRG/WP 118 E
D Dirol, M Fougerousse
Report on the monographic card on Coniophora puteana
1973 - IRG/WP 114
Effect of medium-term degradation of beech wood by erosive (Phanerochaete chrysosporium) and lignin-selective (Ceriporiopsis subvermispora) strains of white rot fungi on its selected physical properties
2004 - IRG/WP 04-40292
At the Faculty of Wood Sciences and Technology a fungal delignification of normal and tension beech wood by erosive and lignin-selective strains white-rot fungi has been studied. The pre-treatment of both kind of wood samples was accompanied by partial delignification and apparent changes of their physical properties influencing the polar liquids penetration.
R Solár, S Kurjatko, M Mamonová, J Hudec
The accelerated field simulator (= fungal cellar)
1982 - IRG/WP 2170
G C Johnson, J D Thornton, H Greaves
Screening-method for the examination of the resistance against contact-insecticides of Lyctus brunneus Steph. beetles
1981 - IRG/WP 2148
A serie of filter-paper rondelles is treated with different concentrations of an organic insecticide dissolved in aceton. Beetles of Lyctus brunneus are put onto the dry surfaces. During the impact of the poison the knock-down is observed and after a following poisonfree holding, the knock-down and mortality are registred.
E Graf, B Lanz
Monographic information on Lentinus lepideus.markup
1973 - IRG/WP 121
G Seehann, W Liese
Temperature influence on the growing velocity and cellulolytic activities of Poria placenta strains from several locations
1986 - IRG/WP 2263
The differences observed on the FPRL 280 Poria Placenta strain at several Research European Laboratories for determining up the fungicide effectiveness of wood preservative has carry us to do a comparative study about the cellulolytic activity and growth velocity of each of this strains at different temperatures (22, 24 and 28°C). The results show significative differences when the temperature is changed.
A M Navarrete, M T De Troya
Evaluation of new creosote formulations after extended exposures in fungal cellar tests and field plot tests
2000 - IRG/WP 00-30228
Although creosote, or coal tar creosote, has been the choice of preservative treatment for the railroad industry since the 1920s, exuding or "bleeding" on the surface of creosote-treated products has been one incentive for further enhancements in creosote production and utility (Crawford et al., 2000). To minimize this exuding problem, laboratories such as Koppers Industries Inc., USA, and Commonwealth Scientific and Industrial Research Organization (CSIRO), Division of Chemical and Wood Technology, Melbourne, Australia, have developed changes in processing of coal tar that produce distillates with fewer contaminants. This "clean distillate" is then used to formulate "clean creosote" as a preservative. These new, unique creosote formulations are being investigated as part of a program to enhance the use of regionally important wood species in the United States. Four retention levels of each of two new creosote formulations creosote, one pigment-emulsified creosote (PEC) and one creosote formulation that meets the AWPA Standard C2-95 for P1/P13 creosote (AWPA, 1995a), were applied to two softwood species and two hardwood species. Two laboratory procedures, the soil-block and fungal cellar tests (accelerated field simulator), were used to evaluate the four creosote formulations. These procedures characterized the effectiveness of the wood preservatives. The soil-block tests were used to determine the minimum threshold level of the preservative necessary to inhibit decay by pure cultures of decay fungi. In general, the soil block tests showed there was little difference in the ability of the four creosote formulations to prevent decay at the three highest retention levels as summarized in a previous report by Crawford and DeGroot (1996). The soil-block tests will not be discussed in this report. Fungal cellar tests expose treated wood to mixtures of soil-borne fungi that promote accelerated attack. Crawford and DeGroot (1996) discussed the evaluation of the creosote formulations after 17 months of exposure in the USDA Forest Service, Forest Products Laboratory (FPL), fungal cellar. At that point in time data from the fungal cellar tests showed that softwoods are protected better than hardwoods for all four formulations of creosote tested. This report will discuss exposure of the fungal cellar stakes upto 36 months. In addition, field stake tests are being used to verify service life of the new creosote formulations in vivo. Results from accelerated tests are indicative of field performance, but the correlation between laboratory and field results is still being investigated. Field stake tests are regarded as critical, long-term evaluations that provide results most directly related to the performance of treated products in service. In this study, we report on the performance of the creosote formulations after five years of exposure in field tests.
D M Crawford, P K Lebow, R C De Groot
An attempt to evaluate wood resistance against fungal decay in non-sterile conditions by measuring the variation of resistance to bending test
1988 - IRG/WP 2308
The main object of this work was to determine the variation of strength on large test specimens of wood (800 x 45 x 45 mm³) when exposed to accelerated fungal attacks close to natural conditions, out of test vessels. The modulus of elasticity (MOE) and the modulus of rupture (MOR) have been assessed. Thereby, the natural resistance of the wood species to fungal decay, the efficiency of preservative as well as the treatment applied are discussed. The wood tested is a guianese secondary species (Couma guianensis). The fungi tested are two guianese strains of brown and white rot. The exposure time is 12 weeks. No mould contamination has been recorded by use of a selective fungicide. The results obtained show that it is possible to infest in nonsterile conditions large wood specimens. Furthermore, modulus of rupture appears to be the most reliable criterion. The investigation, that requires limited equipment and staff could be performed in any tropical research station as it has been done at CTFT, French Guiana center.
L N Trong
A direct method for testing plywood and particle boards against fungal decay
1984 - IRG/WP 2214
A method directly inspired from the French standard testing method of the resistance of particle boards against fungal decay (AFNOR N° 51.295 May 1980) is described. But in that experimentation, the infestation is localized and realized in non sterile conditions. Small blocks of Fagus sylvatica (60 x 20 x 10 mm³) used as " inoculates " are infested with basidiomycetes, in Kolle flask for 4 to 6 weeks, then tightly pressed against the middle part of the test specimens (190 x 15 x 15 mm³). The lower part of the inoculates is plunged in vermiculite kept constantly humid by water containing a selective fungicide. After twelve weeks of exposure in non sterile conditions, in a green house with constant temperature around 20°C, the test specimens are then submitted to a static bending test until fracture. The comparison of the fracture-stress between control test specimens and the specimens exposed to wood rotting basidiomycetes permits to evaluate the resistance of the studied materials against fungal decay.
L N Trong
Report on Sub-group 5 in Raleigh, 6 May 1980
1980 - IRG/WP 1123
A short note on fungal decay in K33-treated poles
1982 - IRG/WP 1169
Soft rot cavities and erosion of the lumen have been found in K33-treated Pinus sylvestris poles from the years 1956-66 by microscopic studies. Poor treatment quality has been proved for some of these poles. The microscopy showed an unusual pattern of attack, and pre-treatment decay is suspected but not yet proved. Sounding the poles and using the Pilodyn indicated decay, but poking did not. Quantification of the attacks was possible only by microscopic studies.
Are fungal cellar tests really necessary?
1989 - IRG/WP 2333
During the past decade the range of methodology used to evaluate wood preservative potential has significantly expanded. At the forefront of these new tools available to the scientist·is the fungal cellar. This technique, as currently applied, involves the exposure of treated and untreated samples to conditions of moisture and temperature which ensure optimum fungal attack. By comparison data with that obtained on similar preservative systems in conventional stake tests, acceleration factors for predicting performance have been developed. This discussion paper examines the philosophy influencing the development of fungal cellar testing, and provides an alternative viewpoint.
J N R Ruddick
Targeting fungal proteinases to prevent sapstain on wood
1995 - IRG/WP 95-10097
Discoloration of wood, caused by a variety of sapstaining fungi, leads to periodic losses in the Canadian lumber export industry. Proteolytic enzymes are thought to be necessary for retrieval of nitrogen during fungal growth on wood. The major extracellular proteinase of Ophiostoma piceae, a representative sapstaining fungus, was purified to homogeneity and its inhibition pattern characterised. Classic serine proteinase inhibitors inhibited the activity of the purified proteinase in a dose-dependent manner. Several chelating agents, detergents, heavy metals and PQ-8, a currently used commercial antisapstain formulation, also caused a reduction in proteolytic activity in vitro. Selected inhibitory compounds were then tested for their effect on growth of Ophiostoma piceae in artificial media and on wood. Heavy metals and several chelators inhibited growth on media containing protein or inorganic nitrogen, suggesting that they were toxic to the fungus rather than specific to the proteinase. However, chymostatin and PQ-8 did appear to be specific proteinase inhibitors. These products caused a decrease in growth on a protein-supplemented medium which induces proteinase production, but had little effect on growth on medium containing inorganic nitrogen. Visual assessment of lodgepole pine sapwood samples inoculated with Ophiostoma piceae also identified PQ-8 as an effective inhibitor of fungal growth. Other pure chelators and serine proteinase inhibitors did not perform well on wood. While some compounds showed promise in these tests, definitive testing and commercial application are constrained by the current lack of stable, cheap, non-toxic, specific serine proteinase inhibitors.
L D Abraham, D E Bradshaw, A Byrne, P I Morris, C Breuil
Some physiological characteristics of a non-degradative strain of Postia (=Poria) placenta
1988 - IRG/WP 1341
The decay capacity of 14 strains of the brown-rot fungus Postia (= Poria) placenta was determined using soil-wood block tests. One isolate was identified as being unable to degrade wood and was determined to be monokaryotic. It retained the ability to produce extracellular carbohydrate-degrading enzymes, although regulation of certain enzymes was atypical under certain cultural conditions. It produced H2O2 and oxalic acid under a variety of carbon and nitrogen regimes, and did not contain double-stranded RNA. It failed to produce large quantities of extracellular polysaccharides in culture. An understanding of the physiology of this isolate would further our knowledge of decay mechanisms leading to safer preservation protocols.
J A Micales, T L Highley