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Role of cell wall structure in soft rot decay of bamboo
1995 - IRG/WP 95-10133
Models of soft rot hyphal penetration of bamboo cell walls are proposed. Soft rot hyphae show an interesting capability of penetrating the bamboo cell wall in different forms; typical longitudinal penetrating hyphae and tangentially orientated penetrating hyphae. The second form of penetration was found to be different from that normally associated with wood cell walls. The differences can be attributed to the cell wall structure of bamboo. Soft rot hyphae normally follow the microfibrillar orientation in either the broad lamellae or the narrow lamellae in bamboo cell walls. Hyphae that grow in the broad lamellae normally penetrate in the longitudinal direction and follow the orientation of the microfibrils of this layer of the cell wall. This produces a 'typical' longitudinal penetrating hyphae and cavity. Soft rot hyphae are also found penetrating in the tangential direction. These arise from radially orientated hyphae trying to penetrate across the lamellated cell wall neighbouring cells. When a radially orientated hyphae encounters the narrow lamellae, the hyphae can reorientate in the direction of the microfibrils in this lamellae. Thus, the hyphae penetrate in a tangential direction in the cell wall. These types of penetrations are not seen in wood cell walls.
O Sulaiman, R J Murphy

Changes in pore structure and cell wall volume in wood decayed by brown- and white-rot fungi
1991 - IRG/WP 1501
Sweetgum (Liquidambar styraciflua L.) wood blocks were decayed by Postia (=Poria) placenta or Phanerochaete chrysosporium in soil-block cultures. Decay was terminated at various weight losses, and the pore volumes available to probes of various molecular weight and diameter were determined by the solute exclusion technique (Stone, J.E. and A.M. Scallan. 1968. Cellulose Chem. Technol. 2, 343-358.). The volume in sound (undecayed) wood that was accessible to the probes varied from 1.0 ml g-1 for the largest to 1.35 ml g-1 for water. Thus, the volume in sound wood attributable to cell wall was 0.35 ml g-1. In brown-rotted samples, the volume of pores in the cell wall increased steadily to 0.7 ml g-1at 35% weight loss. New cell wall volume was accessible to low molecular weight probes but not to molecules of Mr ³ 6,000. Within experimental error, no pores of > 20Å were observed in sound wood or >38Å in brown-rotted wood. Most of the new cell wall volume create by rermoval of components during decay was in the pore size range of 12Å to 38Å. Our results are consistent with the hypothesis that the initial depolymerization of cellulose, characteristic of brown rot, is caused by a diffusible agent. The molecular diameter of the agent is apparently in the range 12Å to 38Å and it causes erosion and thus enlargement of the pores to which it has access. In the white-rotted wood, cell wall volume increased to 0.6 ml g-1 at 40% weight loss and maximum pore diameter increased to 50Å. Most of the cell wall volume increase resulted from the creation of pore of 20-50Å diameter. Analysis of loss of major wood components as a function of weight loss revealed that lignin, cellulose, and hemicellulose were removed at approximately equal rates. Under our experimental conditions, ligninolytic enzymes have access to only a small portion of the new cell wall volume, even after extensive decay.
D S Flournoy

The effect of water storage on the cell-structure of Sitka spruce (Picea sitchensis) with reference to its permeability and preservation
1970 - IRG/WP III 3A
Commercial treatment trials with full sized transmission poles have shown that water storage considerably improves the permeability of Sitka and Norway spruce. These results were confirmed by laboratory measurements which showed that in the sapwood of ponded Sitka spruce there is a vast improvement in permeability in all three grain directions. Heartwood permeability does not seem to be affected to any great degree. Detailed examination of the ponded sapwood by optical and electron microscopy showed that the tori and bordered pit membranes have been destroyed. This would explain its increased longitudinal and tangential permeability. Destruction of the bordered pit membranes would also affect radial permeability but it is thought that the main factor contributing to increased radial penetration was the partial breakdown of the crossfield pit membranes of the ray parenchyma cells. The microscopic examination showed no evidence of cell wall degradation. Preliminary tests have not revealed any deterioration of the strength properties of the wood due to prolonged ponding. There is evidence to indicate that the destruction of the pit membranes was caused by bacterial attack. Microbiological investigations are now in progress and it is hoped that this work will establish the identity and the mechanism of attack of these organisms.
J A Dunleavy, A J McQuire

The effect of certain wood extractives on the growth of marine micro-organisms
1977 - IRG/WP 438
S E J Furtado, E B G Jones, J D Bultman

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

Comparison of cubic and plug samples for preparation and data assembly in permeability study
2000 - IRG/WP 00-20197
In order to determine if plug experimental samples (PES: 30 x 15 mm2 diameter) could be used for inspection of wood permeability characteristics, radial and longitudinal flow directions were prepared according to either PES or cubic experimental samples (CES: 100 x 20 x 20 mm3) from the sapwood zone of Sitka spruce and treated by tanalith-C according to full-cell process. Results from the two preparation techniques agreed in the test to determine the mean percentage of void volume filled by liquid both radially and longitudinally, while the preparation process (i.e. machining, sealing, etc.) of the experimental samples and the period of the data collection was quite longer in CES than that for PES in either flow direction.
I Usta

Ultra-structural observations on the degradation of wood surfaces during weathering
1987 - IRG/WP 2280
Radiata pine (Pinus radiata D. Don) sapwood was converted into blocks with a transverse face about 5 mm square and measuring 8 mm longitudinally. Transverse (T.S.), Radial (R.L.S.) and Tangential (T.L.S.) surfaces were prepared and specimens exposed to the weather inclined at 45° facing equatorially for periods of between 20-60 days. After 30 days exposure erosion of the middle lamella was observed followed after 40 days exposure by extensive separation of individual fibres at the interface of the middle lamella and secondary wall. Degradation of the S2 layer of the cell wall revealed corrugations orientated parallel to the fibre axis suggesting preferential removal of cell wall components. Further degradation proceeded by progressive delamination and checking of the S2 and erosion of the S3 cell wall layer. In addition to the above changes preferential degradation of the rays was observed in radial (R.L.S.) and tangential (T.L.S.) longitudinal surfaces.
P D Evans, S Thein

Resistance of Alstonia scholaris vestures to degradation by tunnelling bacteria
1992 - IRG/WP 92-1547
Electron microscopic examination of vessels and fibre-tracheids in the wood of Alstonia scholaris exposed to tunnelling bacteria (TB) in a liquid culture showed degradation of all areas of the secondary wall. The highly lignified middle lamella was also degraded in advanced stages of TB attack. However, vestured pit membranes and vestures appeared to be resistant to degradation by TB even when other wall areas in Alstonia scholaris wood cells were severely degraded. The size comparison indicated vestures to be considerably smaller than TB, and we suspect that this may primarily be the reason why vestures in Alstonia scholaris wood were found to be resistant to degradation by TB.
A P Singh, T Nilsson, G F Daniel

European standardization for wood preservation
1989 - IRG/WP 2335
G Castan

An effective preservative treatment of borak bamboo (Bambusa balcoona Roxb.)
1996 - IRG/WP 96-40070
Adequate penetration and retention of CCA and CCB has been obtained in predried Borak Bamboo (Bambusa balcooa Roxb.), aboundantly grown in Bangladesh, with Full Cell Pressure Process. The treated bamboo can be used as building materials, the sufficient treatability ensured its long term best utilization at ground contact and indoors. Which will keep the environmental & socio economical conditions of Bangladesh more viable and normal.
A K Lahiry, S Begum, G N M Ilias, M A Matin Sheikh, M A B Fakir, M I Hossain

Ultrastructural observations on wood-degrading erosion bacteria
1986 - IRG/WP 1283
G F Daniel, T Nilsson

A behaviour of CCA penetration of fir (Abies bornmulleriana Mattf.) at different ramp times and constant vacuum/pressure applications
2006 - IRG/WP 06-40346
A behaviour of CCA penetration of Bornmulleriana fir (Abies bornmulleriana Mattf.) at different ramp times and constant vacuum/pressure applications was illustrated for the main flow directions by the experimental pictures.
I Usta, R Despot, M Hasan

Basidiosporogenesis by the white-rot basidiomycetes in vitr
1994 - IRG/WP 94-10081
Basidiospores of all forest-inhabiting basidiomycetes are a primary source of infection causing wood decay. However, most studies evaluating wood preservatives have used mycelia or basidiospores obtained from wild mushrooms. The objective of this study was to demonstrate in vitro methods that promote carpogenesis and basidiosporogenesis by the white-rot basidiomycetes, Schizophyllum commune and Trametes versicolor. After preincubation in the dark at 27°C for three to fifteen days, basidiospores were produced in four to sixteen weeks in basidiomes exposed to light at 12°C. Adequate light exposure, aeration, and low temperature treatment after preincubation are essential for fruiting body of these white-rotting basidiomycetes. Carpogenesis and basidiosporogenesis of Schizophyllum commune is controlled by nitrogen and carbon limitation. However, fruiting body formation in Trametes versicolor was induced by nitrogen limitation. Walset cellulose was found to be the best carboun source for carpogenesis and subsequent basidiosporogenesis. These results demonstrate the feasibility of using various potential inhibitors on basidiospore germination rather than relying on mycelial growth.
S C Croan

What can DNA fingerprinting, aggression tests and morphometry contribute to the identification of colonies of the Formosan subterranean termite
2000 - IRG/WP 00-10371
Multilocus DNA fingerprinting, aggression tests and morphometry were compared to evaluate their potential for the identification of colonies of the Formosan subterranean termite, Coptotermes formosanus (Isoptera: Rhinotermitidae) in Hawaii. DNA fingerprinting separates the termites from all studied collection sites. Since the genetic similarity between termites from different collection sites lies in the range of the genetic background similarity in the population, collection sites in this study represent independent colonies. No significant differences could be found in the intra- and intercolonial aggression levels. While aggression tests do not support colony identification, morphometric measurements do show differentiations between colonies. However, classification of individuals to their original colony does not reach the 100% success provided by genetic analyses. No correlation between genetic similarities and aggression levels or morphometric distances could be found. This suggests that neither aggression levels nor morphometric parameters are significantly influenced by genetic factors in this species. Genetic studies appear to be the most useful approach to the identification of colonies and the analysis of small scale population structures in C. formosanus.
C Husseneder, J K Grace

Analysing the characteristic role of moisture content for drying and fluid flow in Sitka spruce. - Part 1: The drying process of sapwood and heartwood of two different thickness of Sitka spruce using a kiln. - Part 2: Effects of moisture content on longitudinal permeability of Sitka spruce in vertical variation of the tree
2000 - IRG/WP 00-40173
The characteristic role of the moisture content in Sitka spruce (Picea sitchensis (Bong.) Carr.) that grown in the United Kingdom was examined by this study on the basis of (1) the reduction of moisture content in two different thickness of sapwood and heartwood by kiln drying process, and (2) the effects of moisture content to the longitudinal void volume filled of tanalith-C by the full-cell process from base (1 m) to apex (3 m) of the tree in sapwood zone. Accordingly, conclusions on indication of the drying process of sapwood and heartwood, and vertical variation of longitudinal flow with effects of moisture were listed separately: (1) Comparison of Drying Characteristic of Sapwood and Heartwood: The two different thickness (300x30x30 mm3 and 300x20x20 mm3) of sapwood and heartwood of Sitka spruce was dried using the suggested drying schedule in kiln. The reduction of moisture was schematically diagrammed according to sapwood and heartwood stakes. The reduction of moisture followed the same downward trend that sapwood (S) loses more moisture than heartwood (H) although the small stakes of S and H lost moisture rapidly compared with the large ones. (2) Vertical Variation of Moisture Content and Longitudinal Permeability: The 90 kiln dried defect free sapwood stakes (150x25x25 mm3) of Sitka spruce was taken from base to apex of the trees at 1, 2 and 3 m above ground level. After having the determination of moisture content in each experimental stake, the treatment was carried out by the full-cell process with CCA preservative (Tanalith-C) using a model pressure treatment plant. Significant differences observed among the tree heights from 1 to 3 m showing that slightly increases of moisture content from base to apex and conversely decreases of longitudinal void volume filled by preservative fluid.
I Usta

Water-based water repellents for treatment of wood
1987 - IRG/WP 3446
The water uptake by wood can be reduced by treatment with a water repellent. The water repellents most commonly used are solvent based. In the present work a new type of water repellent that is water-based has been investigated. Two different treatments have shown an effect of the same order as a commercial solvent based product. The cellular distribution of the water repellents has been investigated and for one of the formulations a more uniform distribution can be seen at the impregnated surface. Use of water as a solvent would be advantageous due to lower cost and non-toxicity.
I G Svensson, G Hägglund, I Johansson, W B Banks

Effect of methylene bisthiocyanate on morphology and ultra-structure of a sapstain fungus, Ophiostoma floccosum
2003 - IRG/WP 03-10471
In vitro effects of methylene bisthiocyanate (MBT) on hyphal morphology and ultrastructure of Ophiostoma floccosum were examined using differential interference contrast, epifluorescence and transmission electron microscopy (TEM). Differential interference contrast microscopy suggested that MBT caused rapid changes to the morphology of O. floccosum resulting in excessive formation of vacuoles and granules within the cytoplasm. Epifluorescence microscopy indicated that damage to the plasma membrane occurred in the MBT treated, but not the control, hyphae. TEM showed that in MBT treated hyphae, the plasma membrane had retracted from the cell wall. Cytoplasmic aggregation and increased vacuolation were also observed. Furthermore, complete disintegration of the cytoplasmic organelles was seen in more advanced stages of MBT induced damage. In contrast, plasma membrane of untreated hyphae closely adhered to the cell wall showing cytoplasma with typical cell organelles. Based on the results from this study we suggest that the primary site of mode of action of MBT occurred at the plasma membrane, which then triggered subsequent changes within the cytoplasm of the test fungus.
T Singh, B Kreber, R N Wakeling, A Stewart

Termiticidal chemicals derived from tropical tree resins
1991 - IRG/WP 1477
To test the hypothesis that defensive chemicals protect tropical primary forest trees against biological attack, a bioassay and fractionation program was conducted in Indonesia. Fresh dipterocarp resins were fed in no-choice tests to Neotermes dalbergiae termites on 4.5 cm filter papers, or tested for inhibition of fungal growth. Fractionation of biologically active resins via flash column chromatography, followed by subsequent bioassay and analytical chemical studies, revealed that several sesquiterpene compounds inhibited fungal growth and killed 50% of test termites in 3-7 days. Toxic fractions contained caryophyllene, caryophyllene oxide, alloaromadendrene, and other compounds. From the relatively non-toxic a-gurjunene, novel termiticidal compounds were synthesized, indicating the potential for manufacture of insecticides from natural products.
A Messer, K McCormick, D Richardson, Sunjaya, H Hagedorn, J Meinwald

The effects of density on vertical variation of permeability of Sitka spruce within tree
2000 - IRG/WP 00-40156
Tree improvement of Sitka spruce is a combination of silviculture and tree breeding aimed at producing higher quality products including increased growth rate and timber yield, and wood density. It is useful to know annual ring structure and density distribution when studying the quality of wood, grading it, or determining how the wood structure affects residual flow in softwoods. Since density is a factor under genetic control, the study in this article details the effects of density on longitudinal and radial permeability of Sitka spruce from base to apex. Comparison of overall means of both longitudinal and radial void volume filled (%) suggest that longitudinal permeabilities were almost the mirror image of those for the radial permeability along the tree trunk.
I Usta.

Sex pheromone of the male house longhorn beetle Hylotrupes bajulus (L.) (Coleoptera: Cerambycidae)
1995 - IRG/WP 95-10100
Since 1990 studies have been conducted with respect to the chemical communication of the house longhorn beetle Hylotrupes bajulus (L.) (Coleoptera: Cerambycidae). The structure of glands located in the prothorax of the beetles was examined with light and scanning electron microscopy. The analyses of different extracts from beetles resulted in the finding and identification (GC-, GC/MS-, and HR-GC/MS-studies) of specific substances derived from the prothoracal glands: (3R)-3-hydroxy-2-hexanone, (2R,3S)-2,3-hexanediol and (2R,3R)-2,3hexanediol. In wind tunnel experiments, unmated female beetles were attracted over a distance of 1m by males, headspace extracts of males, the 3 major components of the glands as well as by the synthetic blends of the components. Thus, the bioassays revealed the initiation of premating behaviour by emission of a long-range sex pheromone from the male prothoracal glands. The pheromone functions as activator, attractant and possibly aphrodisiac for unmated females. Further studies are conducted with respect to disturbance and prevention of mating behaviour of Hylotrupes bajulus in the attics of houses by using pheromone traps.
U Noldt, R Fettköther, F Schröder, H Meyer, K Dettner, W Francke, W A König

Basidiosporogenesis by brown-rot basidiomycetes in vitro
1995 - IRG/WP 95-10126
Basidiospores of wood-rotting basidiomycetes are a primary sourse of infection causing wood biodeterioration, especially in wood above ground. Most studies evaluating wood preservatives have used mycelia or basidiospores obtained from wild mushrooms. The objective of this study was to demonstrate in vitro methods that promote carpogenesis and basidiosporogenesis by the brown-rot fungi Antrodia carbonisa, Neolentinus lepideus, and Postia placenta. After preincubation in the dark at 27°C for 3 to 11 days, basidiospores were easily prodused in 1 to 4 months by basidiomata exposed to light at 12°C. Adequate light exposure, aeration, and low temperature treatment after preincubation are essential for fruiting body formation of these brown-rot basidiomycetes. The morphology of the basidiomata differed according to the basidiomycetes and the medium used. These results demonstrate that an enormous quantity of basidiosporee can be easily and continuously prodused in 2 to 4 months in vitro.
S C Croan

Fungal degradation of wood treated with metal-based preservatives. Part 2: Redox states of chromium
1996 - IRG/WP 96-10164
Concerns have arisen about the leaching of heavy metals from wood treated with metal-based preservatives, such as chromated copper arsenate (CCA). Of particular concern is the toxic redox state of chromium and arsenic in aging and decayed CCA-treated wood. Generally, hexavalent chromium is more toxic than trivalent chromium and trivalent arsenic is more toxic than pentavalent arsenic. The desired outcome from treating wood with CCA is total change of Cr(VI) to Cr(III) and As(III) to As(V). As part of an on-going study to determine the fate of copper, chromium and arsenic during aging and decay of CCA-treated wood, we detected Cr(III) and Cr(VI) in situ in CCA-treated southern yellow pine lumber. The redox states of Cr were determined using synchrotron X-ray fluorescence spectroscopy (SXRF). An SXRF microprobe was used to to detect Cr redox states by measuring X-ray absorption near-edge structure (XANES). The ratio of Cr(III) to Cr(VI) was determined (1) on the surface and interior of lumber two years after CCA treatment and (2) in lumber during decay by a CCA-tolerant fungus, Meruliporia incrassata TFFH-294. The XANES spectrum for Cr(VI) has a strong pre-edge feature that is not present in the spectrum for Cr(III). Only the Cr(III) XANES spectrum was detected on the surface and in the interior of the wood, indicating total reduction of Cr(VI). The XANES spectrum for Cr(III) was detected in wood after 12 week decay by Meruliporia incrassata TFFH-294, indicating that the fungus does not oxidize Cr(III) to Cr(VI) during the decay process. We are currently using XANES spectroscopy to detect and map in situ redox states of As in CCA-treated wood.
B Illman, S Bajt, T L Highley

The permanence of permethrin in wood preservation
1984 - IRG/WP 3288
The permanence of the synthetic pyrethroid permethrin in treated wood has been assessed for double vacuum and immersion treated Scots pine sapwood and whitewood using a 0.5% m/m solution of the insecticide in a hydrocarbon solvent. It is concluded that for all but the outermost 0.5 mm of the treated battens the distribution of the permethrin is relatively permanent. The outermost 0.5 mm appears vulnerable to degradation rather than volatile loss, and this varies with timber species and the loading in that zone. Linking this information with published bioassay work allows speculation as to the strength of treating solutions needed for adequate long-term protection
R J Orsler, M W S Stone

Degradation of the normal fibre walls of rubberwood (Hevea brasiliensis) by the tropical blue-stain fungus Botryodiplodia theobromae
1998 - IRG/WP 98-10286
Rubberwood was examined by light microscopy and transmission electron microscopy (TEM) after exposure to the common tropical sapstain fungus Botryodiplodia theobromae for four weeks to study hyphal colonisation of wood cells and to determine if this fungus also degraded lignified normal fibre cell walls in addition to the walls of non-lignified elements. Light microscopy revealed relatively large diameter hyphae to be abundantly present in parenchyma cells. The hyphae were also present in other types of wood cells, including fibres. TEM provided evidence of fibre wall degradation in the normal rubberwood in the form of lumen wall erosion (type-2 soft rot decay). These observations suggest that the ability of B. theobromae to degrade lignified wood cells walls should be viewed with concern when utilising rubberwood which has been severely sapstained, particularly after prolonged exposure to this fungus.
A A H Wong, A P Singh

TBTO absorption and penetration in pine joinery treated by various processes
1989 - IRG/WP 3523
Matched sections of several White pine (Pinus strobus) and Ponderosa pine (Pinus ponderosa) mouldings were treated with TBTO by Double vacuum, modified empty-cell, 15 second dip and several preheating treatments followed by a 15 s dip treatments. As expected the double vacuum and empty-cell (batch) treatments resulted in much greater retentions and penetrations than the dip treatments. The absorptions by the 15 s dip treatments could be improved significantly by preheating the wood to 60-90C° by microwave, radio-frequency or infra-red techniques. Since this approach is amenable to a continuous treatment process, it is being evaluated for potential commercial application.
P A Cooper, Y T Ung

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