Fungal–copper interactions in wood examined with large field of view synchrotron-based X-ray fluorescence microscopy

Zelinka, Samuel L.; Jakes, Joseph E.; Tang, Juliet D.; Ohno, Katie M.; Bishell, Amy B.; Finney, Lydia; Maxey, Evan; Vogt, Stefan; Kirker, Grant T.

doi:10.1080/17480272.2018.1458049

Cited by 6 publications

(4 citation statements)

References 21 publications

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“…The high amount of iron uniformly distributed throughout the sample may be a result of trace impurities in the industrial grade treatment chemicals. In previous work using XFM, cell walls of copper treated wood were found to be uniformly higher in iron and this was attributed to impurities in the treatment [28]. Regardless of the reason for the high iron concentration, the differences in the relative amounts of iron and copper make it difficult to directly compare this image to the other wood preservative treatments.…”

Section: Testing Methodsmentioning

confidence: 96%

Copper distribution and oxidation states near corroded fasteners in treated wood

et al. 2019

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Metal fasteners are used to hold wood structures together. In outdoor applications, these fasteners are subject to corrosion when the wood is treated with certain preservative treatments. Typically, these treatments contain copper. Prior work has hypothesized that the mechanism of corrosion in treated wood involves reduction of copper ions from the wood treatments. However, copper was rarely detected in the corrosion products of metals embedded in treated wood, which contradicts the hypothesized mechanism. This present work utilizes synchrotron based X-ray fluorescence microscopy (XFM) and X-ray absorption near edge spectroscopy to examine the corrosion mechanism in treated wood by looking at the spatial distribution and oxidation states of copper in the treated wood near the fastener and in the corrosion products removed from the fastener surface. The samples were obtained after a 1-year corrosion test. In the wood cell walls, the oxidation state of the copper treatment did not change in the immediate vicinity of the fastener, although there was a depletion of copper near the fastener. Furthermore, copper was detected in the corrosion products in trace amounts using XFM. Together, these techniques confirm that the corrosion mechanism involves transport of the cupric ions to the fastener surface, where they are reduced and suggest that previous attempts to detect copper were unsuccessful because the concentration of copper in the corrosion products was below the level of detection of the previously used techniques.

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Section: Testing Methodsmentioning

confidence: 96%

Copper distribution and oxidation states near corroded fasteners in treated wood

et al. 2019

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“…This may indicate that the fungus is able to translocate hydrolysis products out of the wood sample. Ostrofsky et al [80] have demonstrated that R. placenta is able to translocate iron and aluminum cations into wood and synchrotron-based x-ray fluorescence microscopy results from Zelinka et al [81] suggest R. placenta can translocate copper ions. Perhaps the fungus is also able to move the acidic hydrolysis products out of the wood.…”

Section: Discussionmentioning

confidence: 99%

Leachability and Decay Resistance of Wood Polyesterified with Sorbitol and Citric Acid

Beck

2020

Forests

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Research Highlights: Polyesterification of wood with sorbitol and citric acid (SCA) increases decay resistance against brown-rot and white-rot fungi without reducing cell wall moisture content but the SCA polymer is susceptible to hydrolysis. Background and Objectives: SCA polyesterification is a low-cost, bio-based chemical wood modification system with potential for commercialisation. Materials and Methods: This study investigates moisture-related properties and decay resistance in SCA-modified wood. Scots pine sapwood was polyesterified at 140 °C with various SCA solution concentrations ranging from 14–56% w/w. Dimensional stability was assessed and leachates were analysed with high-performance liquid chromatography (HPLC). Chemical changes were characterized with attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) and spectra were quantitatively compared with peak ratios. Low-field nuclear magnetic resonance (LFNMR) relaxometry was used to assess water saturated samples and decay resistance was determined with a modified EN113 test. Results: Anti-swelling efficiency (ASE) ranged from 23–43% and decreased at higher weight percentage gains (WPG). Reduced ASE at higher WPG resulted from increased water saturated volumes for higher treatment levels. HPLC analysis of leachates showed detectable citric acid levels even after an EN84 leaching procedure. ATR-FTIR analysis indicated increased ester content in the SCA-modified samples and decreased hydroxyl content compared to controls. Cell wall water assessed by non-freezing moisture content determined with LFNMR was found to increase because of the modification. SCA-modified samples resisted brown-rot and white-rot decay, with a potential decay threshold of 50% WPG. Sterile reference samples incubated without fungi revealed substantial mass loss due to leaching of the samples in a high humidity environment. The susceptibility of the SCA polymer to hydrolysis was confirmed by analysing the sorption behaviour of the pure polymer in a dynamic vapour sorption apparatus. Conclusions: SCA wood modification is an effective means for imparting decay resistance but, using the curing parameters in the current study, prolonged low-level leaching due to hydrolysis of the SCA polymer remains a problem.

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“…Additional isolates of F. radiculosa (TFFH 294 and L-11659-SP) have been documented to have differences in oxalate accumulation and differential expression of genes encoding a citrate synthase, an isocitrate lyase, a glyoxylate dehydrogenase, a succinate/fumarate antiporter, and a copper transporting ATPase pump over the course of 8 weeks (Ohno et al, 2015). Zelinka et al (2018) used synchrotronbased X-ray fluorescence microscopy to observe copper distribution in SP wood wafers that were dipped in copper sulfate pentahydrate after exposure to three copper-tolerant fungi, F. radiculosa, P. placenta, and F. (Tyromyces) palustris. After exposure to F. radiculosa for 9 weeks, there were much lower copper concentrations remaining in the dipped wafers, but only slightly lower copper concentrations after P. placenta and F. palustris exposure.…”

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confidence: 99%

“…A possible mechanism of copper-tolerance is translocation of copper out of the area of fungal growth. Previous authors have reported that preservative tolerant fungi appear to be able to mobilize preservative elements, including copper, and decrease their concentration in the affected zone (Choi et al, 2012;Hastrup et al, 2014;Zelinka et al, 2018). Relatively few studies have investigated copper-tolerant F. radiculosa for other intracellular methods to overcome the toxic effects of copper (Tang et al, 2013;Ohno et al, 2015).…”

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confidence: 99%

Gene Expression Analysis of Three Putative Copper-Transporting ATPases in Copper-Tolerant Fibroporia radiculosa

2020

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Copper tolerance of brown-rot basidiomycete decay fungi can lessen the efficacy of copper-containing wood preservatives for wood products in-service. The purpose of this study was to evaluate wood mass loss and differential expression of three genes that have putative annotations for copper-transporting ATPase pumps (FIBRA_00974, FIBRA_04716, and FIBRA_01430). Untreated southern pine (SP) and SP treated with three concentrations of ammoniacal copper citrate (CC, 0.6, 1.2, and 2.4%) were exposed to two copper-tolerant Fibroporia radiculosa isolates (FP-90848-T and L-9414-SP) and copper-sensitive Gloeophyllum trabeum isolate (MAD 617) in a 4-week-long standard decay test (AWPA E10-19). Decay of copper-treated wood was inhibited by G. trabeum (p = 0.001); however, there was no inhibition of decay with increasing copper concentrations by both F. radiculosa isolates. Initially, G. trabeum and one F. radiculosa isolate (L-9414-SP) highly upregulated FIBRA_00974 and FIBRA_04716 on copper-treated wood at week 1 (p = 0.005), but subsequent expression was either not detected or was similar to expression on untreated wood (p = 0.471). The other F. radiculosa isolate (FP-90848-T) downregulated FIBRA_00974 (p = 0.301) and FIBRA_04716 (p = 0.004) on copper-treated wood. FIBRA_01430 expression by G. trabeum was not detected, but was upregulated by both F. radiculosa FP-90848-T (p = 0.481) and L-9414-SP (p = 0.392). Results from this study suggest that all three test fungi utilized different mechanisms when decaying copper-treated wood. Additionally, results from this study do not provide support for the involvement of these putative gene annotations for copper-transporting ATPase pumps in the mechanism of copper-tolerance.

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Fungal–copper interactions in wood examined with large field of view synchrotron-based X-ray fluorescence microscopy

Cited by 6 publications

References 21 publications

Copper distribution and oxidation states near corroded fasteners in treated wood

Copper distribution and oxidation states near corroded fasteners in treated wood

Leachability and Decay Resistance of Wood Polyesterified with Sorbitol and Citric Acid

Gene Expression Analysis of Three Putative Copper-Transporting ATPases in Copper-Tolerant Fibroporia radiculosa

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