Your search resulted in 35 documents. Displaying 25 entries per page.
Antifungal mechanism of dichloro-N-octylisothiazolone
1998 - IRG/WP 98-30183
4,5-dichloro-N-octylisothiazolin-3-one (DCOI) is a member of the isothiazolone class of preservatives, whose antimicrobial mechanism of action has been intensively studied over the last decade. DCOI has also been intensively studied for use in wood preservation. The isothiazolones are electrophilic molecules that rapidly react with thiol groups to form covalently bonded isothiazolone-thiol adducts. This ability to bond with thiol groups is crucial to their ability to act as preservatives.
Thiol groups are present in proteins as part of the amino acid cysteine, where they play an important role in maintaining protein structure and function. A number of enzymes have thiol groups at the site where the enzyme function is performed, and these thiol groups may participate in the enzyme reaction. If the isothiazolone reacts with this thiol group, the activity of the enzyme is inhibited. Our studies have shown that there are several enzymes in the Krebs cycle that are inhibited by isothiazolones and these enzymes are required to generate energy and perform many biosynthetic functions. Reflective of this, DCOI has been shown to be a rapid inhibitor of cellular respiration, causing the cell to cease consuming oxygen almost immediately upon contact with DCOI. The multiplicity of targets and their central importance to the metabolism of the cell, as well as the fact that all microbes use at least parts of the Krebs cycle, can be related to the low use levels and broad spectrum of activity of DCOI.
The antimicrobial mechanism of DCOI results in a potent rapid-acting preservative with a broad spectrum of antifungal and antibacterial activity that is effective at low levels.
J S Chapman, M A Diehl, K B Fearnside, L E Leightley
The use of C CP/MAS NMR in the chemical identification of decayed and undecayed, tropical timber species
1984 - IRG/WP 1224
13C CP/MAS NMR was found to be an extremely powerful tool for elucidating the chemical composition of Eucalyptus maculata, Pinus elliottii and Alstonia scholaris. The differences in lignin composition were different for each timber and discussed in relation to decay caused by soft-rot and white rot fungi. In particular the presence of syringyl and guaiacyl lignin types are discussed.
L E Leightley
Procedure for a collaborative study of leaching from CCA-treated timber in the sea
1988 - IRG/WP 4143
As a follow-up to the collaborative IRG/COIPM marine trial of CCA and CCB preservatives, a further trial is proposed with the objective of measuring the degree of leaching of CCA components from three timber species at marine sites in Malaysia and the U.K.. Details of the planned procedure are given....
S M Cragg, J E Barnacle, J D Bultman, R A Eaton, B R Johnson, L E Leightley, K D Singh
Soft rot and bacterial decay in preservative treated eucalypt power transmission poles
1982 - IRG/WP 1155
Bacterial type decay was observed in CCA and PCP treated eucalypt power transmission poles. Detailed observations made with the SEM revealed bacterial colonisation and decay, especially in fibres. Plug samples taken from poles throughout Queensland were examined for preservative retention and presence of soft-rot decay. The severity of decay was different according to location, retention and speci...
L E Leightley
Collaborative field experiment. Questionnaire re site/soil
1980 - IRG/WP 3162
L E Leightley
Extracellular layers of wood decay fungi and copper tolerance
1983 - IRG/WP 1180
Extracellular layers around the hyphae of brown, white and soft rot fungi have been examined using electron microscopy. These layers were isolated for identification. Particular interest was directed towards the extracellular layers of copper-tolerant soft rot fungi....
D M Francis, L E Leightley
A standardised procedure for the treatment of timber with test chemicals
1986 - IRG/WP 2257
A procedure is described which allows the standardisation of sample handling and data manipulation during trials invastigating the treatability of timber with test chemicals. The use of computer software allows the data to be handled efficiently....
J Norton, A Zosars, L E Leightley
An insight into brown rot decay of timber as revealed by 13C CP/MAS NMR
1985 - IRG/WP 1259
L E Leightley
The performance of softwood species used as poles in Queensland
1985 - IRG/WP 1253
In Queensland, the conifer Pinus elliottii could provide material suitable for use as poles. Full size pole material has been readily treated with CCA with no significant loss in strength. Seasoning of logs prior to treatment requires particular attention in the wet tropical and sub-tropical regions of Queensland. Experimental and in service field tests have indicated excellent performance of CCA ...
L E Leightley
IRG soft-rot stake test - Site 03 Australia. Progress Report No. 3
1982 - IRG/WP 3202
The performance of test stakes was examined after four (4) years. Hardwood stakes treated with CCA showed significant soft-rot attack. The exception to this was Alstonia scholaris which was similar in performance to Pinus sylvestris. A supplementary test containing stakes treated with CBC, PCP and creosote, showed attack in all hardwoods examined. Little decay was found in stakes of Pinus sylvestr...
L E Leightley, R S Johnstone
The use of the Pilodyn for detecting soft-rot decay in CCA treated eucalypt poles
1986 - IRG/WP 2251
A 6 Joule Pilodyn unit with 2.5 mm diameter pin was used to inspect CCA treated eucalypt poles, suspected of suffering groundline soft-rot decay. Pole plugs were removed at the inspection region and the amount of soft-rot decay present determined microscopically. High correlation (R² = 0.73) was obtained between the amount of soft-rot and Pilodyn pin penetration. The Pilodyn is recommended as a u...
L E Leightley, G A Willoughby
Patterns of bacterial attack in preservative treated eucalypt power transmission poles
1984 - IRG/WP 1223
Patterns of bacterial decay have been examined using light and scanning electron microscopy. Two morphologically distinct patterns have been recognised in preservative treated eucalypt power transmission poles. Bacterial Decay I (BDI) involves the removal of the secondary wall layers initiating with erosion of the S3 layer from the cell lumen. As decay progresses the S2 layer and S1 layer are degr...
G A Willoughby, L E Leightley
Isolation and identification of bacteria from CCA-treated eucalypt power transmission poles
1987 - IRG/WP 1317
Bacteria have been isolated from CCA treated Eucalyptus maculata poles which possessed characteristic bacterial decay patterns. Cultures were isolated on a number of different media which had been inoculated with a splinter of degraded wood. Primary tests indicated that most isolates belonged to the genera Pseudomonas and Bacillus. The species Pseudomonas cepacia was most frequently isolated....
G A Willoughby, A C Hayward, L E Leightley
Chemical analyses of IRG/COIPM INTERNATIONAL MARINE TEST (to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water) samples
1987 - IRG/WP 4114
Chemical analysis of CCA and CCB treated timber was carried out after exposure at tropical and temperate marine sites. Results indicated that losses of all elements had occurred. In particular, losses of boron were severe. Arsenic and copper were also lost. The chromium components in both formulations was the most dominant metal remaining. The results suggest that chromium modification was importa...
L E Leightley
IRG soft rot stake test. Site: 03 Australia. Progress repor
1980 - IRG/WP 1114
IRG soft-rot test stakes were installed in site 03 Australia 16.6.77. The stakes have been inspected twice, (28.11.78 (Johnson, 1979) and 31.10.79) for signs of decay, and used to obtain fungal isolates. The condition of stakes in the supplementary soft-rot test has also been examined....
L E Leightley, D M Francis, R S Johnstone
Soft rot decay of Eucalyptus maculata Hook. in different soils from Queensland, Australia
1980 - IRG/WP 1113
In the present work, different Queensland soils were chosen and their gross effects on the decay of treated and untreated Eucalyptus maculata examined. The soils were also amended with various levels of phosphate to study the response of the wood decay mycota to an increasing supply of this nutrient. Phosphate amendment was chosen because of the wide-scale use of superphosphate on Queensland soils...
L E Leightley, I W Russell
An evaluation of anti-apstain chemicals in Queensland, Australia
1986 - IRG/WP 3374
Five formulations were evaluated for potential use as antisapstain chemicals. Tolcide FSM (0.01, 0.02, 0.04%), Koppers N.P.-1 (0.70, 0.35, 0.25%), Kathon WT (0.10, 0.25, 0.40%) and Sinesto B (2.5, 5.0 and 7.5%) offer potential as antisapstain treatments. An incorrect stock of Busan 1009 was used resulting in unacceptable results....
L E Leightley
Examination of the Pilodyn as a non-destructive test method for detecting decay in CCA treated eucalypt poles
1982 - IRG/WP 2177
Below groundline condition of 274 CCA treated eucalypt poles comprising 13 different species was examined using 6 and 12 Joule Pilodyn units with 2 and 2.5 mm diameter pins. The data obtained was used to calculate regressions of density on pin penetration. A decrease in density was accompanied by an increase in pin penetration. The best correlation was found using the 6 Joule, 60 x 2.5 mm² diamet...
L E Leightley
High CCA retentions and the protection of eucalypt power poles
1983 - IRG/WP 3226
Tasmanian power pole material treated to high retentions, was analysed to accurately determine the amount of CCA preservative in the timber. Material from the same disc was subsequently exposed in unsterile soil in order to determine the effectiveness of treatment. Results showed that even at high retention levels, soft-rot attack was not prevented. Fourteen further poles were sampled, but this ti...
L E Leightley, J Norton
Soft rot studies on CCA treated eucalypt power transmission poles
1981 - IRG/WP 1132
Initial results found for sixty CCA treated eucalypt poles, from a soft-rot survey are discussed. Retentions of CCA within above and below ground pole samples were variable. The variation was attributed mostly to biodegradation and effect of soil environment, rather than leaching. Bacterial decay was found in many poles and was severe in some cases. Although found in the presence of soft-rot decay...
L E Leightley
Sampling rates and the probability of detecting defective treatment in the sampling of preservative treated timber
1987 - IRG/WP 2277
When attempting to enforce standards of penetration and retention set for treated timber, the regulating authority must establish a sampling or inspection scheme which will prevent large quantities of substandard product entering the market. On the other hand, the scheme should not penalise treaters for the small quantities of such material which are inevitably produced by any industrial process. ...
M J Kennedy, L E Leightley
Microbial breakdown mechanisms. Mini-Symposium at the 18th IRG meeting, Honey Harbour, Ontario, Canada
1987 - IRG/WP 1327
An understanding of how micro-organisms cause chemical alternation to wood is essential for effective wood preservation. Investigation of the Microbial Breakdown of wood is a very dynamic research field and is increasing in importance as several biocides are being examined as alternativesw to classic wood preservatives. These biocides often do not possess broad spectrum activity. It is esential th...
L E Leightley
The use of the Shigometer® and Pilodyn® as non-destructive test methods for detecting decay in CCA treated eucalypt poles
1981 - IRG/WP 2153
The groundline condition of sixty C.C.A. treated eucalypt poles comprising six different species was examined using the Pilodyn® and Shigometer®. Although sensitive to the presence of soft-rot decay, the Shigometer® would seem to offer little practical advantage in the eucalypt soft-rot decay situation, since a comparable visual examination could reveal the presence and extent of decay. Initial...
L E Leightley
The need for realism in wood preservation research. A key address
1983 - IRG/WP 3254
The approval of a chemical for use as a timber preservative and the design of in service retention requirements represents an act linking fundamental research and commercial timber preservation. How difficult is it to translate figures generated through controlled experimentation into working specifications and how confident can we be in the methods used to provide such figures? The chairman of Wo...
L E Leightley
The suitability of isothiazolone microemulsions as long term wood preservatives
1997 - IRG/WP 97-30150
Microemulsion formulations of 4,5 dichloro-2-n-octyl-4-isothiazolin-3-one were investigated to determine the leaching potential of these formulation types as well as their efficacy against decay fungi. These patented low leaching formulations exhibited good anti fungal efficacy in standard tests combined with minimal leaching of the active ingredient from the wood. The data suggests that the excel...
B M Hegarty, Bing Yu, L E Leightley