Your search resulted in 42 documents. Displaying 25 entries per page.
Preliminary studies of the decay mechanism of some brown-rot fungi
1989 - IRG/WP 1402
The importance of the enzymatic degradation of hemicellulose and cellulose by brown-rot fungi is still under discussion. Endo-ß-1,4-xylanase and endoglucanase activities of Coniophora puteana and Poria placenta cultures were measured by the increase in reducing groups. Enzymes were produced in liquid and solid sawdust based culture media. Enzyme activities were measured in two, four and eight wee...
A-C Ritschkoff, H Viitanen
Biological screening assays of wood samples treated with creosote plus chemical additives exposed to Limnoria tripunctata
1980 - IRG/WP 408
Laboratory methods for exposure of treated wood coupons to Limnoria tripunctata are described. Chemical additions to creosote were screened using this method. Three pesticides, Endrin, Kepone, and Malathion proved particularly effective. The addition of varying percentages of naphthalene to creosote using several treatment methods are currently being assayed. Results to date show that the coupons ...
B R Richards, D A Webb
Physical properties of ß-1,4-Xylanase produced by Postia (=Poria) placenta: Implications for the control of brown rot
1987 - IRG/WP 1318
The degradation of hemicelluloses is an early event in wood decay by brown-rot fungi. An understanding of the physical properties of hemicellulases may suggest target mechanisms for the development of new control agents. Endo-b-1,4-xylanase was partially purified by column chromatography from wood decayed by Postia (= Poria) placenta. The enzyme was extremely resistant to denaturing conditions; no...
J A Micales, F Green III, C A Clausen, T L Highley
Use of vermiculite as substrate in assays on phytotoxicity of treated wood
1989 - IRG/WP 3547
It is considered the possibility of using vermiculite instead of soil as substrate in assays on phytotoxicity of wood treated with preservatives for agricultural use. Three organic preservatives were used. It had been tested the behaviour of both, vermiculite and soil in case of preservative leaking due to a leach. So that, assays of germination with cucurbitaceous were carried out, mixing a dose ...
M V Baonza Merino, D Franco
Localization of oxalate decarboxylase in the brown-rot fungus Postia placenta
1996 - IRG/WP 96-10161
Oxalate decarboxylase, the enzyme that breaks oxalic acid down into formic acid and carbon dioxide, was recently detected in mycelial extracts of the brown-rot fungus Postia placenta. Differential centrifugation was used to demonstrate that the enzyme is loosely associated with the hyphal surface. Enzyme activity can be removed by washing the hyphae with a low pH buffer. Only low levels of activit...
J A Micales
The preliminary characterization of ß-1,4-xylanase of the brown-rot fungus Gloeophyllum trabeum
1990 - IRG/WP 1447
The extracellular ß-1,4-xylanase of the brown-rot fungus, Gloeophyllum trabeum, was isolated from crude extract by chromatofocusing method (PBE 94 column chromatography). The isoelectric point was estimated to 4.2-4.8 by cromatofocusing and 4.5 by isoelectric focusing (IEF). The molecular weight of the enzyme was estimated to 37,000 dalton by SDS-PAGE. The optimal temperature for the crude extrac...
A-C Ritschkoff, M Rättö, L Viikari
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
Towards a colour assay of wood degradation
1982 - IRG/WP 2180
A colour assay for the enzyme catalase is described. Since the activity of this enzyme has previously been shown to be correlated with degree of wood degradation as determined by other methods, this assay may provide a rapid quantitative indicator of superficial and internal wood decay....
M A Line
A case for adopting a standardised protocol of field and laboratory bioassays to evaluate a potential soil termiticide
2003 - IRG/WP 03-20275
The rationale for adopting a new approach to the field testing of potential soil termiticides is advocated on the grounds that current testing methods are limited to termite bioassays and do not address quantitatively the persistence and bioavailability of soil termiticides to foraging subterranean termites over time and in different soil types. Furthermore, the present testing regimes assume fiel...
J R J French, B M Ahmed
Physiologic response of Phanerochaete chrysosporium to exposure to triazole fungicides
1994 - IRG/WP 94-10066
Triazoles are increasingly important fungicides which are employed for a variety of applications included wood protection. Several recent studies suggest that white rot fungi are more tolerant of triazole compounds than other wood degrading fungi. Cultural studies using a white rot fungus, Phanerochaete chrysosporium, and 0.2 or 0.8 ppm of tebuconazole or propiconazole suggested that mycelial dry ...
J J Morrell, R K Velicheti
Effects of Trichoderma harzianum on enzyme activity and oxalic acid production of Gloeophyllum trabeum in ponderosa pine sapwood blocks
1992 - IRG/WP 92-1550
The effect of a bioprotectant, Trichoderma harzianum, on the activity of Gloeophyllum trabeum was investigated using a wood wafer sandwich method. Wood weight loss was greatest with Gloeophyllum trabeum exposed wafers, intermediate with those exposed to both the bioprotectant and decay fungus, and lowest with the bioprotectant exposed wafers. Extracts of wood wafers after 2, 4, or 6 weeks of funga...
C M Sexton, J J Morrell
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
A new method for the study of microbiological decay of wood in a strictly anaerobic environment
1988 - IRG/WP 2319
Recent work has suggested that strictly anaerobic bacteria may play a role in the biodeterioration of wood, particularly in aqueous environments. However, no suitable test methods exist for the investigation of this hypothesis. An aqueous minimal medium in specifically adapted conical flasks was sterilised, gassed using a 5.5% H2; 31.8% C02; 62.7% N2 gas mixture to remove oxygen and transferred to...
G M Rogers, A A W Baecker
The probable mechanism of action of boric acid and borates as wood preservatives
1990 - IRG/WP 1450
The tetrahydroxyborate ion [B(OH)4-] acts by complexation with poly-ols and probably attacks decay fungi through extracellular substrate sequestration; intracellular substrate sequestration; enzyme inhibition; and change in membrane function. Work was carried out to investigate this further and to try to explain certain phenomena observed in the area of boron preservation. The effect of Na borate ...
J D Lloyd, D J Dickinson, R J Murphy
Detection of a brown-rot fungus using serological assays
1986 - IRG/WP 1305
Polyclonal antisera produced to Poria placenta (Fr.) Cooke were used in two tests to qualitatively assay for the fungus. Fungal hyphae were fixed to slides and fluorescent antibody (FA) techniques used to visualize the hyphae under the microscope. Fluorescence of non-Poria fungi, when present, could be reduced but not eliminated by cross-absorbing the sera with these fungi. The antisera was also u...
B Goodell, J Jellison
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
Qualifying ecotoxicity research on tropical hardwood leachates
1997 - IRG/WP 97-50096
Almost as a rule, quantification and identification of various types of environmental contamination is grounded on chemical evaluation principles. Yet for monitoring surface water pollution, aquatic bio-assays may provide a more direct way to assess the potential hazard of environmental samples. A battery of such tests is experienced onto leachates of tropical hardwoods used in ground and water co...
G M F Van Eetvelde, P Marchal, M Stevens
The effect of Trichoderma volatiles on the growth and enzyme production of Serpula lacrymans
2000 - IRG/WP 00-10332
Although various authors have reported the biological control of Serpula lacrymans by Trichoderma spp. the mode of antagonism employed by Trichoderma is not yet clear. The work presented here concentrates on the production of anti-fungal volatiles for inhibition of S. lacrymans growth. Volatile mediated interactions were examined between four S. lacrymans isolates and a range of nine known Trichod...
S N Humphris, A Bruce, R E Wheatley
Laboratory testing of wood natural durability - In soil-bed assays
1998 - IRG/WP 98-20141
Laboratory methods for assessing wood decay resistance are being investigated in the framework of an ongoing European research project. This paper summarizes the main results obtained for soil-bed tests based on the European prestandard ENV 807-Test 2. The data suggest that this testing methodology is suitable for evaluating the natural durability of timber species in soil-contact under conditions...
R Sierra-Alvarez, I Le Bayon, J K Carey, I Stephan, J Van Acker, M Grinda, G Kleist, H Militz, R-D Peek
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
Redox regulation of enzyme activity during wood decay
1996 - IRG/WP 96-10172
A potential strategy in the search for alternative wood preservatives against fungal decay is to target the extracellular wood-decay process itself, rather than the decay organisms. This presents novel targets for selective disruption and possibly without the broad-spectrum toxicity associated with conventional wood preservatives. The enzymes of white rot decay are mechanistically diverse (e.g. hy...
P J Kersten, B Kurek, J W Whittaker
Biological control of wood decay fungi. - Part II. Effects of exogenous nitrogen on effectiveness
2000 - IRG/WP 00-10360
The effects of nitrogen (urea and ammonium nitrate) on the ability of Trichoderma harzianum to inhibit the enzyme capabilities and decay capacities of Trametes versicolor and Gloeophyllum trabeum were investigated using a small wood sandwich decay test. The biocontrol fungus generally had a greater effect on the brown rot fungus, confirming previous reports. Nitrogen produced inconsistent effects ...
E A Canessa, J J Morrell
Effect of Pseudomonas cepacia on the activity of a mixture of wood staining fungi on ponderosa pine sapwood
1995 - IRG/WP 95-10107
There are major incentives for limiting the degree of fungal discoloration which occurs during wood processing. Most lumber producers apply prophylactic fungicides which limit microbial growth, but increasing restrictions on the use of these chemicals have encouraged the search for alternative stain prevention strategies. Among the possible strategies for stain prevention is biological control. Wh...
J J Morrell, R K Velicheti
Log fumigation prevents enzyme-mediated sapwood discolorations in hardwoods
1993 - IRG/WP 93-10003
Non-microbial sapwood discolorations in hardwood lumber can cause economic loss by degrade of quality. Based on the hypothesis that the enzyme-mediated sapstain may develop in part from byproducts of parenchyma cells in wood, reshly felled logs of red oak (Quercus spp.) and sugar hackberry (Celtis laevigata) were fumigated under a plastic tarp with methyl bromide. Log sections were checked after f...
E L Schmidt, T L Amburgey
Prevention of non-microbial sapwood discolorations in hardwood lumber: chemical and mechanical treatments
1997 - IRG/WP 97-30137
Sapwood discolorations in hardwood lumber that are non-microbial in origin result from the formation of pigmented starch-like granules in ray parenchyma cells. These discolorations can be prevented by treating unseasoned lumber with an antioxidant (sodium bisulfite). Exposing unseasoned lumber to microwaves or treating logs with fumigants also will prevent these discolorations. Subjecting unseason...
T L Amburgey, S Kitchens