• Journal of the Korean Wood Science and Technology
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• v.36 no.5
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• pp.1-10
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• 2008

Decay and mold resistance of zinc borate (ZB) and calcium borate (CB) modified oriented strandboard (OSB) from southern mixed hardwood and southern yellow pine was investigated in this study. Brown rot fungus Gloeophyllum trabeum and white-rot fungus Trametes versicolar were used to examine the decay resistance of the OSB. The OSB test specimens were colonized by brown and white rot fungal mycelium in both the brown and white-rot culture bottles after 8 and 12 weeks, respectively. The wood species and fungus type had the significant effects on the decay resistance. Brown rot decay was evident for all untreated southern pine and mixed hardwood controls. The white-rot decay, however, did not show significant weight loss at both species control samples. The incorporation of ZB and CB composites provides suitable protection against brown-and white-rot fungi. No significant weight loss was observed from the borate treated OSB.

• Journal of the Korean Wood Science and Technology
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• v.36 no.5
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• pp.24-32
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• 2008

Artificial brown-rot decay was induced to two wood species, Pinus densiflora and Pinus radiata. A modified direct inoculation method was used and the decay indicators of mass loss and two compressive mechanical properties, maximum compressive strength (MCS) and compressive stiffness, were estimated over the period of 8 weeks of fungal exposure. Measurable mass loss occurred 2 weeks after the fungal attack, with 15% to 22% of the loss occurring 8 weeks after fungal exposure with Fornitopsis palustris and Gloeophyllurn trabeurn. Mechanical properties proved to be far more sensitive than mass loss detection: approximately five to six times by quantity. Of the two mechanical properties, MCS was more sensitive to and consistent with progressive brown-rot decay. An ultrasonic test was performed to determine the feasibility and accuracy of this method for nondestructive detection of brown-rot decay. The ultrasonic test is highly sensitive at qualitative detection of the early stages of brown-rot decay.

• Journal of the Korean Wood Science and Technology
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• v.24 no.1
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• pp.81-86
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• 1996

This study was performed to evaluate the reduction in bending properties of radiata pine sapwood associated with incipient brown-rot decay. Decayed bending specimens by Tyromyces palustris and Gloeophyllum trabeum for varoious periods were tested destructively. Brown-rot decay by T. palustris and G. trabeum caused serious reduction in bending properties at very early stages of decay, with about 30 percent decrease in bending strength observed for only 1~2 percent weight loss. In general, the reduction in bending properties caused by T. palustris was somewhat greater than that by G. trabeum. Work to maximum load was reduced most severely and rapidly from the onset of decay, while modulus of elasticity showed a much more moderate rate of reduction. Modulus of rupture was affected by decay to a greater extent than was modulus of elasticity. Since a relatively strong correlation between weight loss and bending strength was observed, the residual strength of decayed wood can be predicted by weight loss due to decay. The results of this study indicate that very early stages of brown-rot decay reduce the bending strength significantly. Thus, it is recommended that all load-bearing members in wooden structures, especially those that are periodically wetted, should be inspected regularly to prevent a sudden failure even though there are no definite signs of decay.

• Journal of the Korean Wood Science and Technology
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• v.42 no.2
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• pp.214-221
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• 2014

The deterioration in wood by the brown-rot fungus (Fomitopsispalustris) and the white-rot fungus (Trametesversicolor) were measured using ultrasonic velocity. Those were used for the decay exposure and 4 wood species of wood as the test specimens, Pinusdensiflora, Larixkaempferi, Pinuskoraiensis and Pinusrigida, were chosen with both the brown- and white-rot culture petridish during 12 weeks. After 12 weeks, the decrease rate of ultrasonic velocity was measured at 10~15%. In both brown- and white-rot exposure experiments, P. rigida showed significant decrease in ultrasonic velocity (20%), L. kaempferi on the other hand did not show decrease in ultrasonic velocity. After the fungal exposure experiment, the inside of specimens was investigated by computer tomography (C/T). After C/T investigation, bending tests were performed.

• Journal of the Korean Wood Science and Technology
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• v.34 no.5
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• pp.1-10
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• 2006

The objective of this study was to elucidate the microscopic patterns of decay caused by brown-rot fungi of Tyromyces palustri and Gloeophyllum trabeum in Korean red pine (Pinus densiflora) and radiata pine (Pinus radiata) woods through light and electron microscopies. The ultrastructural changes of cell walls attacked by the two brown-rot fungi were compared in this respect. Macroscopically, radiata pine showed more ring and radial checks than Korean red pine. Microscopically, with the progress of decay, spiral checks associated with cross-field pits and bore holes in the cell wall were more remarkably numerous in the radiata pine than in the Korean red pine. In the radiata pine, G. trabeum produced more spiral checks in the cell wall than T. palustris. In the advanced stages of decay by G. trabeum, the erosions of ray cell walls were identified both in the Korean red pine and radiata pine but $S_3$ layers of tracheid walls were eroded only in the Korean red pine.

• Mycobiology
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• v.47 no.4
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• pp.506-511
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• 2019

We investigated the antifungal activities of an endophytic fungus identified as Acaromyces ingoldii, found on a loblolly (Pinus taeda L.) pine bolt in Louisiana during routine laboratory microbial isolations. The specific objectives were to determine the inhibitory properties of A. ingoldii secondary metabolites (crude extract) on the mycelial growth of a brown-rot fungus Gloeophyllum trabeum and a white-rot fungus Trametes versicolor, and to determine the effective concentration of A. ingoldii crude preparation against the two decay fungi in vitro. Results show the crude preparation of A. ingoldii from liquid culture possesses significant mycelial growth inhibitory properties that are concentration dependent against the brownrot and white-rot fungi evaluated. An increase in the concentration of A. ingoldii secondary metabolites significantly decreased the mycelial growth of both wood decay fungi. G. trabeum was more sensitive to the inhibitory effect of the secondary metabolites than T. versicolor. Identification of specific A. ingoldii secondary metabolites, and analysis of their efficacy/specificity warrants further study. Findings from this work may provide the first indication of useful roles for Acaromyces species in a forest environment, and perhaps a future potential in the development of biocontrol-based wood preservation systems.

• Journal of the Korean Wood Science and Technology
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• v.20 no.3
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• pp.55-60
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• 1992

Japanese red pine (Pinus densiflora S. et. Z.) decayed by brown-rot fungi Tyromyces palustris and Gloeophyllum trabeum were subjected to X-ray diffraction analysis and infrared spectral examinations. Pine woods decayed by T. palustris showed the increase of relative crystallinity in the initial stage of degradation. When the weight loss was above 30%, then the crystallinity went down slowly. In contrast, the wood samples degraded by G. trabeum showed the decrease of crystallinity from the beginning stage of decay. The changes of crystallinity in brown-rotted woods suggested that the degradation rate of crystalline cellulose was varied with the brown rot fungal species. X-ray diffraction analyses also indicated that crystalline cellulose was much more slowly broken down than the amorphous one. The most notable difference in the IR spectra of the brown-rotted wood samples was that the adsorption band centered at 1,730$cm^{-1}$ was significantly diminished in the decayed wood. indicating the degradation of hemicellulose by brown-rot fungi. However, no marked changes of intensities at 1,000, 1,060 and 1,040$cm^{-1}$ were observed in the brown rotted wood samples, suggesting that crystal line cellulose was resistant against the attack by brown rot fungi.

• Mycobiology
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• v.46 no.2
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• pp.138-146
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• 2018

Two-hundred and fifty-five strains of actinomycetes isolated from soil samples were screened for their antagonistic activities against four well-known wood decay fungi (WDF), including a brown rot fungus, Gloeophyllum trabeum and three white rot fungi Donkioporia expansa, Trametes versicolor, and Schizophyllum commune. A dual culture assay using culture media supplemented with heated or unheated culture filtrates of selected bacterial strains was used for the detection of their antimicrobial activity against four WDF. It was shown that Streptomyces atratus, S. tsukiyonensis, and Streptomyces sp. greatly inhibited the mycelial growth of the WDF tested compared with the control. To evaluate the biocontrol efficacy of S. atratus, S. tsukiyonensis, and Streptomyces sp., wood blocks of Pinus densiflora inoculated with three selected Streptomyces isolates were tested for weight loss, compression strength (perpendicular or parallel to the grain), bending strength, and chemical component changes. Of these three isolates used, Streptomyces sp. exhibited higher inhibitory activity against WDF, especially G. trabeum, as observed in mechanical and chemical change analyses. Scanning electron microscopy showed that cell walls of the wood block treated with Streptomyces strains were thicker and collapsed to a lesser extent than those of the non-treated control. Taken together, our findings indicate that Streptomyces sp. exhibits the potential to be used as a biocontrol agent for wood decay brown rot fungus that causes severe damage to coniferous woods.

• Journal of the Korean Wood Science and Technology
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• v.23 no.4
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• pp.54-59
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• 1995

This experiment was carried out to evaluate the role of oxalic acid metabolism in the incipient decay of brown rotting, and to investigate the effects of various compositions of culture medium. Until 5days incubation, the amount of oxalic acid produced by Tyromyces palustris was increased, while pH was gradually decreased. The difference in oxalic acid production depending on carbon sources was not significant and the pH adjustment of media did not stimulate the production of oxalic acid. In this experiment, hemicellulose was hydrolyzed with 1% oxalic acid, so it is suggested that nonenzymatic acid hydrolysis of hemicelluloses might be involved in the process of incipient decay of brown-rot fungi.

• Journal of Microbiology and Biotechnology
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• v.21 no.4
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• pp.347-358
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• 2011

Fomitopsis palustris, a brown-rot basidiomycete, causes the most destructive type of decay in wooden structures. In spite of its great economic importance, very little information is available at the molecular level regarding its complex decay process. To address this, we generated over 3,000 expressed sequence tags (ESTs) from a cDNA library constructed from F. palustris. Clustering of 3,095 high-quality ESTs resulted in a set of 1,403 putative unigenes comprising 485 contigs and 918 singlets. Homology searches based on BlastX analysis revealed that 78% of the F. palustris unigenes had a significant match to proteins deposited in the nonredundant databases. A subset of F. palustris unigenes showed similarity to the carbohydrateactive enzymes (CAZymes), including a range of glycosyl hydrolase (GH) family proteins. Some of these CAZyme-encoded genes were previously undescribed for F. palustris but predicted to have potential roles in biodegradation of wood. Among them, we identified and characterized a gene (FpCel45A) encoding the GH family 45 endoglucanase. Moreover, we also provided functional classification of 473 (34%) of F. palustris unigenes using the Gene Ontology hierarchy. The annotated EST data sets and related analysis may be useful in providing an initial insight into the genetic background of F. palustris.