Your search resulted in 40 documents. Displaying 25 entries per page.
A new concept of oxalic acid biosynthesis in physiology of copper-tolerant brown-rot fungi
2001 - IRG/WP 01-10394
Recently, a wide variety of roles of oxalic acid (oxalate) in wood decay systems have been receiving much attention. Copper tolerance of wood-rotting basidiomycetes has been believed to be due to the detoxification of copper wood preservatives by oxalate produced by these fungi. However, biochemical mechanism of oxalate biosynthesis in relation to physiology of wood-rotting fungi has not been elucidated although two oxalate-forming enzymes, oxaloacetase and glyoxylate dehydrogenase, have been studied in our laboratory. Recently, a new role of glyoxylate cycle in oxalate biosynthesis in wood- rotting fungi has been presented, and the cycle commonly occurred to varying extents among the fungi although they were grown on glucose. Enzymatic analyses showed that isocitrate was cleaved by isocitrate lyase in the glyoxylate cycle rather than oxidized by isocitrate dehydrogenase in tricarboxylic acid (TCA) cycle, and the fungi were found to lack a normal TCA cycle due to the absence of - ketoglutarate dehydrogenase. It is noteworthy that glucose was efficiently converted to oxalate in a theoretical yield of about 80%, accumulating in the culture media of F. palustris. The results further indicate that acetyl-CoA derived from glucose was not completely oxidized to CO2 in TCA cycle but was mainly converted to oxalate with help of the other coupling metabolic cycles, including glyoxylate cycle. Formation of oxalate from several intermediary metabolites using cell-free extracts of F. palustris confirmed that oxalate is also the final product of the metabolic pathway in the in vitro system. Thus, it is proposed as a new concept that most of copper-tolerant brown-rot fungi may acquire the energy by oxidizing glucose to oxalate, i.e. oxalate fermentation expressed in the following equation; Glucose + 5O2 --> 2 Oxalate + 2CO2 + 4H2O.
E Munir, T Hattori, M Shimada
The evaluation of synergistic effects of chemicals on fungicidal efficacy in crossed-paper tests
1991 - IRG/WP 2383
The mixing effects of wood preservatives were evaluated using the crossed-paper technique. Two filter paper strips (0.7 x 8 cm²) were treated by soaking with different chemicals [fungicides, a termiticide (chlorpyrifos or phoxim), a surface-active agent, a synergistic agent, and a stabilizer], and placed at right angles to each other on a fully grown mycelial mat of a test fungus in a Petri dish. When the four organoiodine fungicides were incorporated with chlorpyrifos or surface active agent, only 3-iodo-2-propynyl butyl carbamate (IPBC) showed the desirable synergistic effect against every wood-decaying fungus tested. Other fungicides did not always tend to produce the synergistic effect with the addition of a surface active agent. 4-Chlorophenyl-3-iodopropargyl formal (IF-1000) appeared to indicate an undesirable antagonistic effect when mixed with either chlorpyrifos or a surface active agent. 3-Bromo-2, 3 diiodo-2-propenylethyl carbamate (EBIP) did not show any synergistic action by mixing with chlorpyrifos and/or a surface active agent, although the fungicidal enhancement was induced satisfactorily by mixing the fungicide with chlorpyrifos, a stabilizer and/or a synergistic agent, especially against Tyromyces palustris and Coriolus versicolor. Similarity of the results obtained in the present investigation and in the previous laboratory decay tests leads to the conclusion that the crossed-paper technique is suitable for the evaluation of the mixing effect of chemicals on fungicidal efficacy.
Dong-heub Lee, K Tsunoda, M Takahashi
Cytochemical localization of hydrogen peroxide in brown rot fungus Tyromyces palustris by cerium chloride technique
1999 - IRG/WP 99-10299
Cerium chloride (CeCl3) was used to localize H2O2 cytochemically for studying relationship between ultrastructural and functional characteristics of cellulose degradation by brown rot fungi. This technique proved very useful in localizing discrete electron-densereactionproducts at high resolution with minimal nonspecific deposition. The cytochemical localization of extracellular H2O2 by CeCl3 using TEM demonstrated the presence of H2O2 within the fungal hyphae. Furthermore, our results give an indication of the diffusion of extarcellular H2O2 from brown-rot decay fungi into the intact wood cell walls in the early stages of decay.
Yoon Soo Kim, Seung-Gon Wi
Fungicidal and termiticidal effectiveness of alkylammonium compounds
1983 - IRG/WP 3232
This paper is related to effectiveness of several AAC's against wood decay fungi and termites by Japanese standardized test methods.
K Tsunoda, K Nishimoto
Studies on the preservation of structrual plywood - Part 1: Decay resistance of structural plywood
1974 - IRG/WP 238
The weight loss and the decreases in the compression strength and in the modulus of elasticity were measured to determine the decay resistance of structural plywood (lauan). Test pieces (50x25xA mm³) were exposed to the wood destroying fungi (Coriolus versicolor and Coriolellus palustris) for 2-3 or 2-4 months. After exposure, the measurement of the compression strength was carried out on the pieces of different thickness (A = 6,12 and 18 mm) and different fibre direction of the face veneer (0°, 45° and 90° to the long side of the test piece). The results obtained were as follows: 1.: The weight loss was small. The greatest weight loss was 9.4% on decaying by Coriolellus palustris for 4 months. 2.: The decreases in the compression strength and in the modulus of elasticity were greater than the weight loss. On decaying by Coriolellus palustris for 4 months, the ratio of decrease of the compression strength was 75% (6 mm - 0°). 3.: For differences of the thickness and of the fibre direction, the weight loss and the decreases the modulus of elasticity in the compression strength and in the modulus of elasticity showed tendencies in order 0° > 45° > 90° and 6 > 12 > 18 mm. 4.: According to the experiment, the face veneer is liable to be easily attacked by the wood destroying fungi, but the decrease in the compression strength was great. So, the face veneer and the cross section should be protected with preservatives for structural use.
K Minami, Y Kenjo, S Sugiyama
Protection of Ochroma pyramidale from fungal decay with N,N-napthaloylhyroxylamine
1998 - IRG/WP 98-30182
Fungal decay of wood in service results in billions of dollars (U.S.) in losses annually. Recent environmental restrictions, both U.S. and international, are limiting and eliminating the use of broad-spectrum, heavy metal biocides for wood preservation. Restrictions result primarily from problems with disposal. New wood preservatives need to be developed and tested which specifically target key elements in the sequence of fungal decay mechanisms. Our laboratory has been experimenting with chemicals which inhibit pectin hydrolysis during incipient brown-rot and white-rot decay in southern pine sapwood (Inter. Biodeter. Biodegrad. 39:103). In the present paper these results are extended to include the tropical hardwood Ochroma pyramidale (balsa). Balsa blocks (24x18x12mm) were exposed to two brown-rot fungi and one white-rot fungus in ASTM soil block tests for 10 weeks. CCA (6.4 km/m3 ) was compared with the calcium binding agent N,N-napthaloylhydroxylamine (NHA; 1.6, 3.2 & 6.4 km/m3 ) in leached and unleached blocks. CCA protected balsa with minimal weight loss (> 7.4%) with no leaching effects. NHA (6.4 km/m3 ) protected balsa (0.3-1.2%) weight loss but leaching raised the weight losses to 25% with the brown-rot fungus Tyromyces palustris. We conclude that NHA can protect balsa against G. trabeum and T. versicolor with comparable efficiency to CCA (leached and unleached) but not T. palustris.
F Green III, T L Highley
Removal of heavy metals from treated wood using biological methods
2005 - IRG/WP 05-50226
Heavy metals were removed from wood treated with copper based preservatives using brown-rot fungus Fomitopsis palustris. The amount of effective elements removed by treatment methods was examined. The relationship between oxalic acid concentration and the amount of heavy metals removed from each treated wood was also investigated. The relationship between fungus weight and removal rate was also included. The removal rates of heavy metals were examined at the different mass of chips and different retention rates and different specimen sizes. Effective element removal rate of preservative-treated wood was compared with different cultivation methods. Based on the results of lab-scale experiment, an air lifting bioreactor was employed for its large-scale operation. The efficiency of bioreactor was evaluated.
Dong-won Son, Dong-heub Lee
Fungal resistance of smoke-dried Cryptomeria japonica wood
1998 - IRG/WP 98-40118
Performance of smoke dried wood on fungal resistance was studied. The maximum temperature of the smoke seasoning was 80-90°C in the drying room and 70-80°C within the wood for 6 days during the treatment for 15 days. Decay resistance of smoke-dried Cryptomeria japonica wood was evaluated using a brown rot fungus, Tyromyces palustris. Weight losses of untreated wood, smoke-dried wood, and smoke-dried wood followed by surface removal of 3 mm in thickness were 53%, 16%, and 21% respectively. After leaching for ten days, their weight losses were 38%, 51%, and 46% respectively. Smoke-dried wood had decay resistant some extent against the brown rot fungus, however its effectiveness disappeared completely during leaching. Smoke-drying did not have any effect on preventing the mould growth.
K Yamamoto, I Momohara, T Nishimura
Effects of boron treatments on partially decayed oak and pitch pine heartwood
1996 - IRG/WP 96-30106
This paper reports results of borate based preservative treatment and leaching experiments on partially decayed oak and pitch pine heartwood. Previous experiments have shown little damage is caused to sound timber of these types when treated with Polybor and Boracol 20 preservatives. This experiment was carried out to assess the suitability of selected borate based preservatives for use in historical ships' timbers and therefore the physical effects of these preservatives on such timber was investigated. The results indicate that weight losses incurred due to treatment with Polybor or Boracol 20 are no more damaging than those incurred by treatment with water. Weight changes were more apparent in decayed timber than in sound timber with greater uptakes in non-leached samples and greater weight losses in leached samples. However, comparable weight changes were recorded between water treated samples and preservative treated samples. Dimensional changes were minimal in most cases, the greatest found in non-leached Boracol 20 samples as expected. These results indicate that treatment with these preservatives is suitable for partially decayed oak and pitch pine heartwood.
S McCutcheon, G M Smith, J W Palfreyman, P Durrant
Effect of light and ventilation condition on the rate of wood decay by the brown rot basidiomycete, Tyromyces palustris
1991 - IRG/WP 1517
Effect of light and the ventilation conditions of incubation jars on the wood decay by Tyromyces palustris (Berk. et Curt.) Murr. FFPRI 0507 was investigated. Under no irradiation of light, the ventilation conditions gave extensive effect on mass loss of the test pieces when the culturing was performed with culture medium designated in Japanese Industrial Standard (JIS) A 9302 (Medium A; glucose 4.0%, malt extract 1.5%, peptone 0.3%). On the other hand, no such kind of effect for ventilation conditions was recognized under light conditions, and the wood decay by the fungus accelerated by additional light irradiation of a considerably small intensity. Next, we investigated the relationship between light and the culture medium composition during the wood decay by the fungus. It was found that almost equivalent mass loss occurred after 60-90 days of cultures when the culturings were performed under light-shield conditions with medium A, the culture medium designated in Japan Wood Preserving Association (JWPA) standard No.1 (medium B; malt extract 2.0%, peptone 1.0%), and another culture medium diluted medium B by two times (medium C). Under the irradiation of light, the mass loss on the cultures in medium B and C was markedly less than that in the same media under no irradiation conditions. These results suggested that effect of light on the wood decay by Tyromyces palustris depended on the concentration of glucose in the culture medium. Further, we also investigated the activities of several extracellular and cell wall bound enzymes in wood meal medium contained medium A. From our experimental results, the activities of cellulase (b-1,4-glucan 4-glucanohydrolase, E.C. 220.127.116.11) and mannanase (b-1,4-mannan mannanohydrolase) depended on light irradiation during the wood decay and these enzyme activities may give extensive effect on the mass loss by Tyromyces palustris.
T Suzuki, M Higaki
Bending creep test of plywoods under long term exposure to fungal attack
1981 - IRG/WP 2163
Bending creep test and decay test were coupled in order to evaluate the durability of structural plywoods and preservative efficacy. Experimental blocks, 5.0 x 1.2 cm² section x 35.0 cm length, were impregnated with distilled water and inoculated with mycelial fragments of test fungus. Polyethylene bags stretched with metal frame were used as decay chambers. The chambers containing inoculated blocks and water were plugged with porous silicone plugs. Weight was hanged from the center of block. The deflection at the center of span was measured with a gauge sensor connected with a recorder. The deflection due to fungal attack appeared after 800-1200 hrs incubation. Non-treated plywoods failed by 2400 hrs. Treated plywoods containing 1 kg/m³ of TBP (Tribromophenol) did not fail even after 3800 hrs but deflected continuously. When containing 5 kg/m³ of TBP, only a slight deflection was observed. Based on the assumption that decay advanced uniformly in the parallel direction to the span but wavy like as cosine curve in the perpendicular one, creep deflections were calculated and compared with the experimental ones. It may be concluded from these results that the method is promissing for evaluating the durability of structural board materials and preservative efficacy.
Preservative effectiveness of medium temperature creosote oil
1990 - IRG/WP 3597
Medium temperature creosote oil (MTC) was prepared by removing light naphthalene oil and heavy anthracene oil from the coal tar by means of fractional distillation. We conducted the effectiveness test of MTC in accordance with the JWPA method for testing effectiveness of surface coatings with preservatives against decay fungi. The soil treatment test against Serpula lacrymans was also carried out with Kanuma-soil. Preservative effectiveness of MTC was sufficient for wood against Tyromyces palustris and Serpula lacrymans. The hyphal growth of Serpula lacrymans to the treated layer with MTC from the nutrient one is suppressed in the soil treatment test.
S Doi, A Yamada, Y Suda
Immunolocalization of extracellular metabolites from Tyromyces palustris
1991 - IRG/WP 1491
Polyclonal antisera produced to extracellular metabolites from the brown-rot fungus Tyromyces palustris was used in immunogold TEM studies. Gold labelling was detected in the fungal cell wall and extracellular slime layer but little or sporadic labelling was noted within the cytoplasm of the fungal hyphae. Gold particles were also found within the wood cell wall of Pinus densiflora decayed by Tyromyces palustris. Erosion of wood cell wall and penetration of hyphae in the wood cell wall were frequently observed. The degradation pattern of lignocellulose by brown-rot fungus was also discussed.
Yoon Soo Kim
Biological resistance of aldehyde-treated wood
1994 - IRG/WP 94-40018
Biological resistance of wood treated with aldehyde cross-linking agents such as glyoxal, glutaraldehyde and dimethylol dihydroxy ethyleneurea (DMDHEU) were investigated. Sapwood blocks of Japanese cedar and Japanese beech, measuring 20 x 20 x 10 mm³ (T x R x L), were vacuum-impregnated at room temperature with 5-25% of aldehyde solutions. Blocks were kept in the solution for 1 week to gain the optimum swelling until they were sunk at the bottom, air-dried for 1 week, and cured at 120°C for 24 hours, under SO2-catalysis. After treatment, they were throughly rinsed in running water for several days to leach out the unreacted aldehyde agent. Biological resistance tests were conducted in laboratory by exposing to brown-rot fungus Tyromyces palustris, white-rot fungus Coriolus versicolor, and the two subterranean termites, Coptotermes formosanus and Reticulitermes speratus. Glutaraldehyde was most effective to eliminate the attack of Japanese cedar by all test organisms. Decay by both fungi was almost nil in the treated cedar even at the lowest 5% solution of this agent. A complete death of both termites was gained also in glutaraldehyde-treated cedar at the same concentration. DMDHEU treatment was also effective to enhance the biological resistance of Japanese cedar. Enhancement of biological resistance was recognized also in Japanese beech treated with these agents, but it was somewhat lower than in Japanese cedar. Such a difference might be related to the value of dimensional stability resulted from the treatments. Glyoxal treatment exihibited throughly a poor effect to improve the biological resistance and the dimensional stability of both wood species.
S Yusuf, Y Imamura, M Takahashi, K Minato
Effect of cyclic change of temperature on fungal growth and mass loss
1994 - IRG/WP 94-10065
For estimating the effect of cycling change of temparature on fungal growth, four Japanese species, sugi (Cryptomeria japonica), hinoki (Chamaecyparis obtusa), akamatsu (Pinus densiflora) and buna (Fagus crenata), four fungal species, Tyromyces palustris, Gloeophyllum trabeum, Coriolus versicolor, Pycnoporus coccineus, and five temperature conditions, 10, 20, 27, 35°C and cyclic temperature (20°C 12 hours and 30 or 27°C 12 hours) under constant humidity (75% RH) were examined. The results were summarised that the cyclic condition was rather high fungal growth rate in the case of majority of fungi tested but was not surely increased the mass loss of wood. This tendency is rather clear in the case of brown rot like Tyromyces palustris. The cyclic temperature conditions were not favorable to the groth of Serpula lacrymans.
K Suzuki, K Okada
Biochemical relationships between biodegradation of cellulose and formation of oxalic acid in brown-rot wood decay
1991 - IRG/WP 1472
Non-enzymic hydrolysis of cellulose with low concentrations of oxalic acid was examined. The incubation of pine wood pulp with 1% oxalic acid (pH 1.3) at 35°C for 4 weeks reduced the original viscosity to 60%. Reducing sugars were liberated from various cellulosic samples by the oxalic acid treatment. However, crystallinities of cellulose in those samples did not change before and after the treatments. Then, the enzymatic formation of oxalic acid was investigated in relation to cellulose biodegradation by brown-rot fungi. We succeeded in isolating oxaloacetase from the brown-rot fungus Tyromyces palustris in cell-free extracts which catalyze hydrolysis of oxaloacetate to produce oxalate and acetate. During the brown-rot wood decay process, oxaloacetase may play an important role in degradation of wood carbohydrate.
M Shimada, Y Akamatsu, A Ohta, M Takahashi
Decay and termite durabilities of heat-treated wood
2004 - IRG/WP 04-40272
Decay and termite resistances of Plato-treated timbers were evaluated using a modified JIS decay test method, feeding test in a laboratory scale and a field exposure against Reticulitermes speratus (Kolbe) or Coptotermes formosanus Shiraki. The results showed that no significant decay durability of the treated timbers although mass loss from decay slightly decreased in case of treated timbers. Treated alder and birch were drastically fed by termite in a laboratory scale feeding test. Filed trials also showed the same results as the laboratory scale test.
S Doi, K Hanataa, E Kamonji, Yuuji Miyazaki
Preservative-efficacy of boric acid-triethanol amine solution against wood-decay fungi
1994 - IRG/WP 94-30050
Laboratory preservative-efficacy tests were conducted using boric acid-triethanol amine (BTEA) solution in accordance with the JIS A 9201 (1991) test method excluding the standard weathering process. Sapwood specimens of Picea jezoensis or Fagus crenata to achieve nominal retentions of 0.40-41.2 kg/m³ of boric acid were exposed to Tyromyces palustris, Coriolus versicolor, Serpula lacrymans or Chaetomium globosum, respectively. Mean percentage mass loss data showed the following threshold values: 1.65-2.13 kg/m³ for Tyromyces palustris; 1.60-1.94 kg/m³ for Coriolus versicolor; 0.43-0.83 kg/m³ for Serpula lacrymans; 8.0-23.8 kg/m³ for Chaetomium globosum. The values against Coriolus versicolor and Serpula lacrymans were lower than those of Tim-Bor® as boric acid retention.
S Doi, M Mori, Y Mineki
Comparative studies on the species effects of wood preservatives
1989 - IRG/WP 3521
For the examination of the resistance against fungal attack, wood blocks of 3 softwood species were treated with CCA (type 3), CFK, AAC and IF-1000 independently. The wood blocks were exposed to the fungal decay with Tyromyces palustris. The degradation of the wood blocks treated with these preservatives was quite widely different among wood species examined in this study. Hem-fir treated with CCA and radiata pine treated with CFK showed less durability than the other species and other preservatives. In the case of Cryptomeria japonica, all preservatives tested gave good results. The micromorphological distribution of preservatives in cell walls was investigated with the wavelength dispersive X-ray spectrometry. The X-ray photoelectron spectroscopy was applyed for the investigation on the possibility of conversion reactions with preservatives in impregnated wood. The interaction of extractives with preservatives was examined using a conventional bioassay method for evaluations of the efficacy of wood preservatives against fungi. The concentration of Cr in the CCA treated wood was 1.5-1.6 times higher in the ray parenchyma cell walls than in tracheid walls in every wood species examined. The oxidation of wood occur during the treatments with CCA and CFK, however, there were not conspicious differences in the degree of oxidation among wood species. Although the hot water extractives themselves accelerated the mycelial growth, only the extractives of hem-fir reduced the efficacy of CCA.
K Yamamoto, S Matsuoka
Preservative ability of wood to be fixed hydroxyl apatite substituted for antimicrobial metals
2001 - IRG/WP 01-30272
We succeeded in forming hydroxy apatite (HAp) in wood. HAp is non-toxicity and safe. Preservative ability of the wood, which substituted one part of Ca of constituent element of this HA p for antibacterial metals was measured. When Ca was substituted for Ag or Zn, mass loss in decay by brown-rot fungus F. palustris was restrained in about 50% (Ag) ~30% (Zn) of value of control specimen. However, when Ca was substituted for Cu, because F. palustris was copper-resistant microorganism, there was hardly the preservative ability. In case of decay by white-rot fungus T. versicolor, when Ca was substituted for Ag or Cu, the preservative ability was shown. In particular high preservative ability was provided when Ca was substituted for Cu + Zn or Ag + Zn. However, there was hardly the preservative ability when Ca was substituted for only Zn.
Y Haruhiko, I Sumaru
Variation of natural durability of sugi (Cryptomeria japonica) wood in 15 clones examined by decay test (Preliminary report)
2004 - IRG/WP 04-10526
Natural durability of wood in 27 trees from 15 clones of sugi (Cryptomeria japonica)　 was investigated by an accelerated decay test. Thirty years old trees were collected from a clonal trial in Ibaraki prefecture, Japan. Natural durability is usually evaluated in heartwood. Mass losses of heartwood caused by a brown rot decay fungus, Fomitopsis palustris and a white rot decay fungus, Pycnoporus coccineus were ranged from 0% to 29% and 0% to 14% respectively. The coefficients of their variation among 27 sample trees were 80 % and 38% in mass loss of heartwood by these fungi. Heartwood from one clone was subjected to be low level of mass loss by both fungi. Trees from the clone could be classified into durable. It might be possible to select sugi clones having durable heartwood.
K Yamamoto, A Tamura, R Nakada
Targeted inhibition of wood decay (Using everything but the kitchen sink)
1997 - IRG/WP 97-10203
Low molecular weight oxidative decay agents have been implicated in the degradation of wood by brown-rot decay as evidenced by chemical analysis of brown-rotted wood and detection of oxalic acid and hydroxy radicals. Fenton chemistry (H2O2 / Fe++) is often proposed as the mechanism for generating hydroxy radicals. Previous authors have shown iron to enhance the brown-rot hydrolysis of wood, while others have shown suppression of brown-rot by organic and inorganic metal chelators. We have attempted to inhibit brown-rot and white-rot decay of southern pine and maple wood blocks in a series of soil block decay tests using a variety of chemicals targeted specifically at key components of proposed brown-rot mechanisms. Included in these tests were inorganic and organic chelators, calcium coordinating compounds, wood binding dyes, microbial siderophores and common antioxidants -- some previously tested. All chemicals were screened at 1% aqueous (w/v). Only 2 of 28 compounds were effective in significantly reducing wood weight loss by all fungi tested in 12 weeks: napthaloylhydroxylamine (NHA) -- a calcium precipitating agent; and ruthenium red (RR) -- a pectin stain. Both compounds bind preferentially to pit tori and ray parenchyma cells as observed by light microscopy. Targetting the woody substrate for inhibition of decay looks more promising than targetting fungal physiology
F Green III, T A Kuster, T L Highley
Difference of CCA efficacy among coniferous wood species
1990 - IRG/WP 3601
Wood blocks of Cryptomeria japonica, Tsuga heterophylla, and Pinus radiata successively extracted with n-hexane, ether, and methanol were treated with various concentrations of CCA type 3, which were subjected to the decay by Tyromyces palustris. The weight loss were different among species and kinds of extraction. Cryptomeria japonica treated with CCA had higher fungal resistance than Tsuga heterophylla and Pinus radiata. Pre-extraction did not contribute to improve the durability of CCA treated wood of all species. ESCA analysis indicated that the reduction of Cr(IV) to Cr(III) took place, and increase of C1 component (C-H or C-C bond) of C 1s spectra occurred during drying. Fixation of CCA was restricted in the shallow region of blocks in the case of 1.6% concentration. The CCA treatment increased the water repellency of all species, but there were not a wide difference among species. Leachability was high in the section specimens treated with CCA. But the amount of CCA leached was small and reached area was restricted near the surfaces in the block specimens. Amounts of nitrogen in wood surface influenced the decay resistance of wood. The fungal growth on ager-malt mediums containing extractives and CCA was smaller in methanol extractives than the others. The cause of species difference of CCA efficacy was not still explained well.
K Yamamoto, M Inoue
Properties-enhanced albizzia particleboards by incorporating fungicide and insecticide in the glue
1994 - IRG/WP 94-30060
Preservative-treated particleboards were prepared by using tropical fast-growing albizzia and adding fungicides and insecticides to the adhesive-glue. the physical and biological properties of these boards were evaluated. No significant reduction in bending or internal-bond strength due to incorporation of the chemicals was detected. Treated particleboards effectively resisted attack by Coptotermes formosanus at an active ingredient (a.i.) retention of less than 0.5 kg/m³ for chlorpyrifos, dichlorophenthion and propetanphos in laboratory tests. Although decay was unaffected by incorporating the mixed preservative at the retention levels in this study, boards which contained IF-1000 as a fungicide an an a.i. retention of more than 1.0 kg/m³ showed the possibility of decay resistance.
B Subiyanto, S Yusuf, Y Imamura, S Fushiki, T Saito, T Katuzawa
Extracellular hydrogen peroxide-producing and one-electron oxidation system of brown-rot fungi
1990 - IRG/WP 1445
Wood-component-degrading compounds involved in the initial degradation of the cellulose and lignin in wood were isolated from wood-containing culture of brown-rot fungi, Gloeophyllum trabeum and Tyromyces palustris and partially purified by gel filtration on Sephadex G-25 and DEAE-Sepharose ion-exchange chromatography. The compounds were glycoproteins. The molecular weights of the glycoproteins as determined by gel filtration were very small and about 1,600-2,000. The one-electron oxidation activity of the peptides was determined by measuring ethylene production from 2-keto-4-thiomethylbutyric acid (KTBA). The peptides contained ferrous iron,required H2O2 for KTBA oxidation, were capable of catalyzing the oxidation of NADH to produce H2O2 in the presence of 02 and showed little phenol-oxidase activity under conditions giving high activity against KTBA. The ferrous iron combined with the glycopeptides was oxidized to the ferric state by H2O2.
A Enoki, S Yoshioka, H Tanaka, G Fuse