The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Jonathan S Schilling - One of the best experts on this subject based on the ideXlab platform.
-
coupling secretomics with enzyme activities to compare the temporal processes of wood metabolism among white and brown rot Fungi
Applied and Environmental Microbiology, 2018Co-Authors: Gerald N Presley, Ellen A Panisko, Samuel O Purvine, Jonathan S SchillingAbstract:ABSTRACT Wood-degrading Fungi use a sequence of oxidative and hydrolytic mechanisms to loosen lignocellulose and then release and metabolize embedded sugars. These temporal sequences have recently been mapped at high resolution using directional growth on wood wafers, revealing previously obscured dynamics as Fungi progressively colonize wood. Here, we applied secretomics in the same wafer design to track temporal trends on aspen decayed by Fungi with distinct nutritional modes: two brown rot (BR) Fungi (Postia placenta and Gloeophyllum trabeum) and two white rot (WR) Fungi (Stereum hirsutum and Trametes versicolor). We matched secretomic data from three zones of decay (early, middle, and late) with enzyme activities in these zones, and we included measures of total protein and ergosterol as measures of fungal biomass. In line with previous transcriptomics data, the Fungi tested showed an initial investment in pectinases and a delayed investment in glycoside hydrolases (GHs). Brown rot Fungi also staggered the abundance of some oxidoreductases ahead of GHs to produce a familiar two-step mechanism. White rot Fungi, however, showed late-stage investment in pectinases as well, unlike brown rot Fungi. Ligninolytic enzyme activities and abundances were also different between the two white rot Fungi. Specifically, S. hirsutum ligninolytic activity was delayed, which was explained almost entirely by the activity and abundance of five atypical manganese peroxidases, unlike more varied peroxidases and laccases in T. versicolor. These secretomic analyses support brown rot patterns generated via transcriptomics, they reveal distinct patterns among and within rot types, and they link spectral counts with activities to help functionalize these multistrain secretomic data. IMPORTANCE Wood decay, driven primarily by wood-degrading basidiomycetes, is an essential component of global carbon cycles, and decay mechanisms are essential for understanding forest ecosystem function. These Fungi efficiently consolidate pretreatment and saccharification of wood under mild conditions, making them promising templates for low-cost lignocellulose conversion. Species are categorized as ligninolytic white rots and polysaccharide-selective brown rots, with considerable undescribed variability in decay mechanism that may manifest in the sequential variation in protein secretion over the progression of decay. Here we resolved spatially a temporal progression of decay on intact wood wafers and compared secretome dynamics in two white and two brown rot Fungi. We identified several universal mechanistic components among decay types, including early pectinolytic “pretreatment” and later-stage glycoside hydrolase-mediated saccharification. Interspecific comparisons also identified considerable mechanistic diversity within rot types, indicating that there are multiple avenues to facilitate white and brown rots.
-
distinct growth and secretome strategies for two taxonomically divergent brown rot Fungi
Applied and Environmental Microbiology, 2017Co-Authors: Gerald N Presley, Jonathan S SchillingAbstract:Brown rot Fungi are wood-degrading Fungi that employ both oxidative and hydrolytic mechanisms to degrade wood. Hydroxyl radicals that facilitate the oxidative component are powerful non-selective oxidants and are incompatible with hydrolytic enzymes unless they are spatially segregated in wood. Differential gene expression has been implicated in Postia placenta to segregate these reactions, but it is unclear if this two-step mechanism varies in other brown rot Fungi with different traits and life history strategies, and that occupy different niches in nature. We used proteomics to analyze a progression of wood decay on thin wafers, using brown rot Fungi with significant taxonomic and niche distance - Serpula lacrymans (Boletales; ‘dry rot9 lumber decay) and Gloeophyllum trabeum (order Gloeophyllales; slash, downed wood). Both Fungi produced greater oxidoreductase diversity upon wood colonization and greater glycoside hydrolase activity later, consistent with a two-step mechanism. The two Fungi invested very differently, however, in terms of growth (infrastructure) versus protein secretion (resource capture), with ergosterol/extracted protein ratio increased 7x with S. lacrymans than with G. trabeum . In line with their native substrate associations, hemicellulase specific activities were dominated by mannanase in S. lacrymans and by xylanase in G. trabeum . Consistent with previous observations, S. lacrymans did not produce GH 6 cellobiohydrolases (CBH) in this study, despite taxonomically belonging to the order Boletales, which is distinguished among brown rot Fungi by having CBH genes. This work suggests that distantly related brown rot Fungi employ staggered mechanisms to degrade wood, but that the underlying strategies vary among taxa. Importance Wood-degrading Fungi are important in forest nutrient cycling and offer promise in biotechnological applications. Brown rot Fungi are unique among these Fungi in that they use a non-enzymatic oxidative pretreatment before enzymatic carbohydrate hydrolysis, enabling selective removal of carbohydrates from lignin. This capacity has evolved multiple times, independently, but it is unclear if different mechanisms underpin similar outcomes. Here, we grew Fungi directionally on wood wafers, and we found similar two-step mechanisms in taxonomically divergent brown rot Fungi. Results, however, revealed strikingly different growth strategies, with S. lacrymans investing more in biomass production than secretion of proteins, and G. trabeum showing the opposite pattern with a high diversity of uncharacterized proteins. The “simplified” S. lacrymans secretomic system could help narrow gene targets central to oxidative brown rot pretreatments, and comparing its distinctions with G. trabeum and other brown rot Fungi (e.g. Postia placenta ) might offer similar traction in non-catabolic genes.
-
Using a grass substrate to compare decay among two clades of brown rot Fungi
Applied Microbiology and Biotechnology, 2013Co-Authors: Justin T. Kaffenberger, Jonathan S SchillingAbstract:Interest in the mechanisms of wood-degrading Fungi has grown in tandem with lignocellulose bioconversion efforts, yet many potential biomass feedstocks are non-woody. Using corn stover ( Zea mays ) as a substrate, we tracked degradative capacities among brown rot Fungi from the Antrodia clade, including Postia placenta , the first brown rot fungus to have its genome sequenced. Decay dynamics were compared against Gloeophyllum trabeum from the Gloeophyllum clade. Weight loss induced by P. placenta (6.2 %) and five other Antrodia clade isolates (average 7.4 %) on corn stalk after 12 weeks demonstrated inefficiency among these Fungi, relative to decay induced by G. trabeum (44.4 %). Using aspen ( Populus sp.) as a woody substrate resulted in, on average, a fourfold increase in weight loss induced by Antrodia clade Fungi, while G. trabeum results matched those on stover. The sequence and trajectories of chemical constituent losses differed as a function of substrate but not fungal clade. Instead, chemical data suggest that characters unique to stover limit decay by the Antrodia clade, rather than disparities in growth rate or extractives toxicity. High p -coumaryl lignin content, lacking the methoxy groups characteristically cleaved during brown rot, is among potential rate-distinguishing characters in grasses. This ineptitude among Antrodia clade Fungi on grasses was supported by meta-analysis of other unrelated studies using grass substrates. Concerning application, results expose a problem if adopting the strategy of the model decay fungus P. placenta to treat corn stover, a widely available plant feedstock. Overall, the results insinuate phylogenetically distinct modes of brown rot and demonstrate the benefit of using non-woody substrates to probe wood degradation mechanisms.
-
lignocellulose modifications by brown rot Fungi and their effects as pretreatments on cellulolysis
Bioresource Technology, 2012Co-Authors: Jonathan S Schilling, Robert A Blanchette, Shona M Duncan, Timothy R Filley, Ulrike W TschirnerAbstract:Brown rot Fungi Gloeophyllum trabeum and Postia placenta were used to degrade aspen, spruce, or corn stover over 16 weeks. Decayed residues were saccharified using commercial cellulases or brown rot fungal extracts, loaded at equal but low endoglucanase titers. Saccharification was then repeated for high-yield samples using full strength commercial cellulases. Overall, brown rot pretreatments enhanced yields up to threefold when using either cellulase preparation. In the best case, aspen degraded 2 weeks by G. trabeum yielded 72% glucose-from-cellulose, a 51% yield relative to original glucan. A follow-up trial with more frequent harvests showed similar patterns and demonstrated interplay between tissue modifications and saccharification. Hemicellulose and vanillic acid (G6) or vanillin (G4) lignin residues were good predictors of saccharification potential, the latter notable given lignin's potential active role in brown rot. Results show basic relationships over a brown rot time course and lend targets for controlling an applied bioconversion process.
-
Iron and calcium translocation from pure gypsum and iron-amended gypsum by two brown rot Fungi and a white rot fungus
Holzforschung, 2008Co-Authors: Jonathan S Schilling, Kaitlyn M. BissonnetteAbstract:AbstractWood-degrading Fungi commonly grow in contact with calcium (Ca)-containing building materials and may import Ca and iron (Fe) from soil into forest woody debris. For brown rot Fungi, imported Ca2+may neutralize oxalate, while Fe3+may facilitate Fenton-based degradation mechanisms. We previously demonstrated, in two independent trials, that degradation of spruce by wood-degrading Fungi was not promoted when Ca or Fe were imported from gypsum or metallic Fe, respectively. Here, we tested pine wood with lower endogenous Ca than the spruce blocks used in prior experiments, and included a pure gypsum treatment and one amended with 1% with FeSO4. Electron microscopy with microanalysis verified that brown rot FungiSerpula himantioidesandGloeophyllum trabeumand the white rot fungusIrpex lacteusgrew on gypsum and produced iron-free Ca-oxalate crystals away from the gypsum surface. Wood cation analysis verified significant Fe import by both brown rot isolates in Fe-containing treatments. Wood degradation was highest in Fe-gypsum-containing treatments for all three Fungi, although only wood degraded byI. lacteushad significant Ca import. We suggest that Fe impurities may not exacerbate brown rot, and that both brown and white rot Fungi may utilize Ca-containing materials.
Jody Jellison - One of the best experts on this subject based on the ideXlab platform.
-
temporal changes in wood crystalline cellulose during degradation by brown rot Fungi
International Biodeterioration & Biodegradation, 2009Co-Authors: Caitlin Howell, Barry Goodell, Anne Christine Steenkjær Hastrup, Jody JellisonAbstract:Abstract The degradation of wood by brown rot Fungi has been studied intensely for many years in order to facilitate the preservation of in-service wood. In this work we used X-ray diffraction to examine changes in wood cellulose crystallinity caused by the brown rot Fungi Gloeophyllum trabeum, Coniophora puteana, and two isolates of Serpula lacrymans. All Fungi increased apparent percent crystallinity early in the decay process while decreasing total amounts of both crystalline and amorphous material. Data also showed an apparent decrease of approximately 0.05 A in the average spacing of the crystal planes in all degraded samples after roughly 20% weight loss, as well as a decrease in the average observed relative peak width at 2θ = 22.2°. These results may indicate a disruption of the outer most semi-crystalline cellulose chains comprising the wood microfibril. X-ray diffraction analysis of wood subjected to biological attack by Fungi may provide insight into degradative processes and wood cellulose structure.
-
Decay Resistance Properties of Hot Water Extracted Oriented Strandboard
Wood and Fiber Science, 2009Co-Authors: Caitlin Howell, Juan Jacobo Paredes, Jody JellisonAbstract:The use of extracted wood hemicelluloses as a substrate for fermentation and biofuels production has the added benefit of leaving the remaining wood product intact after extraction and being usable in other applications. However, it is still unclear how these extraction procedures might affect susceptibility to fungal attack. Modified oriented strandboards (OSB) were created by hot water extracting red maple strands before adhesive application and pressing of the strands into boards. Treated and untreated boards were tested for decay susceptibility in a modified ASTM soil block jar bioassay using multiple species of white and brown rot Fungi. Results showed no significant differences in decay susceptibility between the untreated and extracted boards for all the brown rot Fungi tested. The white rot Fungi tested were shown to decay the boards made from extracted strands significantly less than the boards made from control strands. These results indicate that modifying OSB panels by removing hemicelluloses for use in ethanol and other alternative fuel production does not increase decay susceptibility to the brown rot Fungi tested and appears to confer a degree of decay resistance against the white rot Fungi.
-
Methods Useful in Assessing Biological and Chemical Activity of Low-Molecular-Weight Brown Rot Fungal Metabolites
Manual of Environmental Microbiology Third Edition, 2007Co-Authors: Jody Jellison, Barry S. Goodell, Yuhui QianAbstract:This chapter provides an overview of selected techniques that are used to detect, quantify, and evaluate the activity of low-molecular-weight metabolites produced by the brown rot Fungi. The role of low-molecular-weight fungal metabolites in the brown rot decay process and their potential use in bioremediation and industrial processes are also briefly considered. The chapter also talks about the techniques used in the purification, quantification, and characterization of selected types of low-molecular-weight metabolites produced by brown rot Fungi. Detection of hydroxyl radicals is limited by their extremely short half-life and high level of chemical activity. The chapter talks about selected methods that have been used in the characterization of wood or lignocellulose colonized by brown rot Fungi or treated with isolated fungal metabolites. These include cellulose chain length determination, X-ray analysis, molecular beam mass spectroscopy (MBMS) and near infrared spectroscopy (NIR) evaluation of complex substrates, and 13C thermochemolysis characterization of lignin modification. Bioremediation applications are particularly intriguing because of the demonstrated ability of brown rot Fungi to ramify through soil and colonize wood and other substrates in the natural environment. The ability to characterize the underlying nonenzymatic microbial processes utilized by the brown rot Fungi will contribute to our ability to both control and utilize these unique degradative organisms in a better manner.
-
Iron-reducing capacity of low-molecular-weight compounds produced in wood by Fungi
Holzforschung, 2006Co-Authors: Barry Goodell, Jody Jellison, Geoffrey Daniel, Yuhui QianAbstract:Birch and pine wood specimens were colonized by individual isolates of 12 Brown-Rot, 26 white-rot, six soft-rot and four blue (sap)-stain Fungi. Homogenized wood was subsequently extracted in 75% ethyl acetate and centrifuged. The filtered extracts were analyzed for their iron-reducing capabilities using a ferrozine-based assay. Agar fungal cultures were also examined directly using a spot test for iron reduction. Extracts from wood colonized by Brown-Rot Fungi showed significantly greater iron-reducing capability than extracts from wood colonized by white-rot or non-decay Fungi. Results of the spot test ratings were highly variable, but in general the greatest color responses were associated with the Brown-Rot cultures. The ability of Brown-Rot Fungi to produce compounds and/or modify the wood components that reduce iron is of relevance to the "chelator-mediated Fenton mechanism" that has been advanced as a theory for the non-enzymatic degradation of wood by Brown-Rot Fungi.
-
Metal Accumulation without Enhanced Oxalate Secretion in Wood Degraded by Brown Rot Fungi
Applied and environmental microbiology, 2006Co-Authors: Jonathan S Schilling, Jody JellisonAbstract:Brown rot Fungi were incubated in agar and agar-wood microcosms containing metallic or hydroxide forms of Al, Cu, and Fe. Metal dissolution was associated with elevated oxalate concentrations in agar, but metals translocated into wood did not affect oxalate accumulation, crystal production, or decay rate, demonstrating a substrate-dependent oxalate dynamic.
Anne Christine Steenkjær Hastrup - One of the best experts on this subject based on the ideXlab platform.
-
Detection of iron-chelating and iron-reducing compounds in four brown rot Fungi
Holzforschung, 2013Co-Authors: Anne Christine Steenkjær Hastrup, Trine Østergaard Jensen, Bo Boye Busk JensenAbstract:The presence of iron-chelating and iron-reducing compounds has been evaluated qualitatively and quantitatively in the four brown rot Fungi Meruliporia incrassata (M. incrassata), Gloeophyllum trabeum (G. trabeum), Coniophora puteana (C. puteana) and Serpula lacrymans (S. lacrymans). Samples of actively growing mycelium from liquid growth media, decayed wood, and agar plate cultures were in focus. Ironchelating compounds were found in all four species, with the highest reactivity in G. trabeum and S. lacrymans, and the lowest in M. incrassata . Iron-reducing activity, measured in the liquid medium, was found in all four Fungi. However, in wood extractions, S. lacrymans was not effective in this regard, although the agar grown mycelium of this fungus showed the highest iron-reducing capacity of the four. The presence of both catecholate and hydroxamate chelators was detected in all four species. G. trabeum showed the highest concentration overall of extracellular chelators, including both catecholate and hydroxamate derivatives.
-
Enzymatic oxalic acid regulation correlated with wood degradation in four Brown-Rot Fungi
International Biodeterioration & Biodegradation, 2012Co-Authors: Anne Christine Steenkjær Hastrup, Frederick Green, Patricia K. Lebow, Bo Boye Busk JensenAbstract:Abstract Oxalic acid is a key component in the initiation of Brown-Rot decay and it has been suggested that it plays multiple roles during the degradation process. Oxalic acid is accumulated to varying degrees among Brown-Rot Fungi; however, details on active regulation are scarce. The accumulation of oxalic acid was measured in this study from wood degraded by the four Brown-Rot Fungi – Gloeophyllum trabeum , Meruliporia incrassata , Coniophora puteana , and Serpula lacrymans – and found to vary significantly. The amount of oxalic acid present was shown to correlate with the mass loss during wood degradation. However, it did not appear to be a direct or causal relationship as G. trabeum produced significantly lower levels of oxalic acid than the other three Fungi but generated comparable weight loss. Oxalic acid decarboxylating activity was detected from wood extractions of all four Fungi with extractions from G. trabeum -inoculated wood showing the highest activity. Formic acid was measured in extractions from decayed wood by the four Brown-Rot Fungi, supporting the presence of the fungal produced oxalic-acid-degrading enzyme oxalate decarboxylase (EC 4.1.1.2). Thus this study indicates that the Brown-Rot species tested, and in particular G. trabeum , are capable of regulating oxalic acid during wood decay by decarboxylation.
-
temporal changes in wood crystalline cellulose during degradation by brown rot Fungi
International Biodeterioration & Biodegradation, 2009Co-Authors: Caitlin Howell, Barry Goodell, Anne Christine Steenkjær Hastrup, Jody JellisonAbstract:Abstract The degradation of wood by brown rot Fungi has been studied intensely for many years in order to facilitate the preservation of in-service wood. In this work we used X-ray diffraction to examine changes in wood cellulose crystallinity caused by the brown rot Fungi Gloeophyllum trabeum, Coniophora puteana, and two isolates of Serpula lacrymans. All Fungi increased apparent percent crystallinity early in the decay process while decreasing total amounts of both crystalline and amorphous material. Data also showed an apparent decrease of approximately 0.05 A in the average spacing of the crystal planes in all degraded samples after roughly 20% weight loss, as well as a decrease in the average observed relative peak width at 2θ = 22.2°. These results may indicate a disruption of the outer most semi-crystalline cellulose chains comprising the wood microfibril. X-ray diffraction analysis of wood subjected to biological attack by Fungi may provide insight into degradative processes and wood cellulose structure.
-
the effect of cacl2 on growth rate wood decay and oxalic acid accumulation in serpula lacrymans and related brown rot Fungi
Holzforschung, 2006Co-Authors: Anne Christine Steenkjær Hastrup, Carol A Clausen, Bo Boye Busk Jensen, Frederick GreenAbstract:The dry rot fungus, Serpula lacrymans, is one of the most destructive copper-tolerant Fungi causing timber decay in buildings in temperate regions. Calcium and oxalic acid have been shown to play important roles in the mechanism of wood decay. The effect of calcium on growth and decay was evaluated for 12 strains of S. lacrymans and compared to five Brown-Rot Fungi. This was done by treating copper citrate (CC)-treated Southern yellow pine (SYP) wood with a CaCl2 solution and estimating the decay rate and amount of soluble oxalic acid in an ASTM soil block test. Decay by S. lacrymans was found to be significantly inhibited by treatment with CaCl2 in the presence of copper. In addition, calcium showed no effect on two strains of S. lacrymans and one Serpula himantioides strain in non-copper-treated SYP wood blocks. The growth rate of S. lacrymans was not affected on malt extract agar containing CaCl2. In summary, a marked decrease was observed in the decay capacity of S. lacrymans in pine treated with CCqCaCl2. The amount of soluble oxalic acid was measured in CC-treated blocks and blocks also treated with CaCl2. Of the comparative Brown-Rot Fungi, both Antrodia vaillantii (TFFH 294) and Postia placenta (Mad 698) displayed notable wood decay despite CaCl2 treatment, while the remaining strains were inhibited.
Carol A Clausen - One of the best experts on this subject based on the ideXlab platform.
-
the effect of cacl2 on growth rate wood decay and oxalic acid accumulation in serpula lacrymans and related brown rot Fungi
Holzforschung, 2006Co-Authors: Anne Christine Steenkjær Hastrup, Carol A Clausen, Bo Boye Busk Jensen, Frederick GreenAbstract:The dry rot fungus, Serpula lacrymans, is one of the most destructive copper-tolerant Fungi causing timber decay in buildings in temperate regions. Calcium and oxalic acid have been shown to play important roles in the mechanism of wood decay. The effect of calcium on growth and decay was evaluated for 12 strains of S. lacrymans and compared to five Brown-Rot Fungi. This was done by treating copper citrate (CC)-treated Southern yellow pine (SYP) wood with a CaCl2 solution and estimating the decay rate and amount of soluble oxalic acid in an ASTM soil block test. Decay by S. lacrymans was found to be significantly inhibited by treatment with CaCl2 in the presence of copper. In addition, calcium showed no effect on two strains of S. lacrymans and one Serpula himantioides strain in non-copper-treated SYP wood blocks. The growth rate of S. lacrymans was not affected on malt extract agar containing CaCl2. In summary, a marked decrease was observed in the decay capacity of S. lacrymans in pine treated with CCqCaCl2. The amount of soluble oxalic acid was measured in CC-treated blocks and blocks also treated with CaCl2. Of the comparative Brown-Rot Fungi, both Antrodia vaillantii (TFFH 294) and Postia placenta (Mad 698) displayed notable wood decay despite CaCl2 treatment, while the remaining strains were inhibited.
-
Copper tolerance of Brown-Rot Fungi : Oxalic acid production in southern pine treated with arsenic-free preservatives
International Biodeterioration & Biodegradation, 2005Co-Authors: Frederick Green, Carol A ClausenAbstract:The voluntary withdrawal of chromated copper arsenate (CCA)-treated wood from most residential applications has increased the use of non-arsenical copper-based organic wood preservatives. Because the arsenic component of CCA controlled coppertolerant Fungi, scientists have renewed interest in and concern about the decay capacity in the important copper-tolerant group of Brown-Rot Fungi. We have demonstrated that the primary means of inactivating copper in preservatives is by excess production of oxalic acid (OA). Oxalic acid production is a key metabolic indicator of Brown-Rot decay, and our objective was to estimate the production of OA in five commercial or experimental arsenic-free preservatives. Ten aggressive Brown-Rot Fungi, chosen from previous studies and representing the genera Antrodia, Coniophora, Gloeophyllum, Postia, Serpula, Tyromyces, and Wolfiporia, were tested against southern yellow pine (SYP) blocks that were vacuum-treated with ground contact retentions of copper naphthenate, amine copper azole, alkaline copper quat type D (ACQ-D), N,N -naphthaloylhydroxylamine (NHA), and copper borate in a 12week soil-block test. After determination of block weight loss, blocks were also tested for the presence of OA. Weight loss ranged from 0.3% to 8.3% for treated blocks and from 16.4% to 59.6% for untreated controls. We conclude that SYP treated with these five preservatives limited OA production and prevented decay, and thus confirmed the efficacy of the co-biocides against coppertolerant Fungi. © 2005 Elsevier Ltd. All rights reserved.
-
copper tolerance of brown rot Fungi time course of oxalic acid production
International Biodeterioration & Biodegradation, 2003Co-Authors: Frederick Green, Carol A ClausenAbstract:Abstract The increase in the use of non-arsenical copper-based wood preservatives in response to environmental concerns has been accompanied by interest in copper-tolerant decay Fungi. Oxalic acid production by Brown-Rot Fungi has been proposed as one mechanism of copper tolerance. Fifteen Brown-Rot Fungi representing the genera Postia , Wolfiporia , Meruliporia , Gloeophyllum , Laetiporus , Coniophora , Antrodia , Serpula , and Tyromyces were evaluated for oxalic acid production bi-weekly in southern yellow pine (SYP) blocks treated with 1.2% ammoniacal copper citrate (CC). Eleven Fungi were designated copper-tolerant based upon weight loss in CC-treated blocks. After 2 weeks, these Fungi produced 2–17 times more oxalic acid in CC-treated blocks than in untreated blocks. After 10 weeks, weight loss ranged from 32% to 57% in CC-treated SYP. Four Fungi were copper sensitive, producing low levels of oxalic acid and minimal weight loss in CC-treated blocks. Rapid induction of oxalic acid appeared to correlate closely with copper tolerance. We conclude that the Brown-Rot Fungi tested that were able to exceed and maintain an oxalic acid concentration of ⩾600 μmol / g effectively decayed SYP treated with CC.
-
Experimental method to quantify progressive stages of decay of wood by basidiomycete Fungi
International Biodeterioration & Biodegradation, 2002Co-Authors: Simon Curling, Carol A Clausen, Jerrold E. WinandyAbstract:A biological exposure method was developed that allows wood samples to be progressively removed for monitoring colonization and decay by basidiomycete Fungi. Monitoring involves strength tests, determination of weight loss, and chemical analysis. To optimize the procedure, several variations of the method were tested using two species of Brown-Rot Fungi (Gloeophyllum trabeum and Oligoporus placentus (Postia placenta)) and one white-rot species (Trametes versicolor) against southern pine sapwood. The variations involved type of culture medium and exposure method. All variations enabled substantial and rapid decay. Specimens exposed to Brown-Rot Fungi lost 80-100% strength and 25-40% weight after 12 weeks; the white-rot fungus was less effective, but nevertheless caused 20-40% loss in strength. For both brown- and white-rot Fungi, strength loss exceeded weight loss. For Brown-Rot Fungi, there was a direct relationship between strength loss and weight loss, suggesting a quantitative relationship between strength loss and chemical composition (hemicellulose sugars) during incipient decay of southern pine by these Fungi.
-
Induction of polygalacturonase and the formation of oxalic acid by pectin in Brown-Rot Fungi.
World journal of microbiology & biotechnology, 1995Co-Authors: Frederick Green, Carol A Clausen, Thomas A. Kuster, Terry L. HighleyAbstract:Extracellular polygalacturonase (PG) production was estimated in vitro, using liquid cultures of three species of Brown-Rot decay Fungi (Postia placenta, Gloeophyllum trabeum and Serpula incrassata), by cup-plate assay, assay of reducing sugars, and decrease in viscosity. Although all three experimental assays demonstrated that PG was induced by pectin in all three Fungi, decrease in viscosity gave the best correlation with decay capacity in soil block tests. PG activity, determined as an increase in reducing sugar activity, was greatest in G. trabeum and weakest in S. incrassata. The optimum pH for PG activity was between pH 2.5 and 4.5. Oxalic acid production was also enhanced by pectin and functioned synergistically with PG activity. We conclude that these Fungi produce PG that is best induced by pectin and that PG activity exceeds production of xylanase and endoglucanase activity in vitro. Polygalacturonase is likely to act synergistically with oxalic acid to solubilize and hydrolyse the pectin in pit membranes and middle lamellae. Thus, production of PG and oxalic acid should facilitate early spread of hyphae and enhance the lateral flow of wood-decay enzymes and agents into adjacent tracheids and the wood cell wall, thus initiating the diffuse decay caused by Brown-Rot Fungi.
Barry Goodell - One of the best experts on this subject based on the ideXlab platform.
-
temporal changes in wood crystalline cellulose during degradation by brown rot Fungi
International Biodeterioration & Biodegradation, 2009Co-Authors: Caitlin Howell, Barry Goodell, Anne Christine Steenkjær Hastrup, Jody JellisonAbstract:Abstract The degradation of wood by brown rot Fungi has been studied intensely for many years in order to facilitate the preservation of in-service wood. In this work we used X-ray diffraction to examine changes in wood cellulose crystallinity caused by the brown rot Fungi Gloeophyllum trabeum, Coniophora puteana, and two isolates of Serpula lacrymans. All Fungi increased apparent percent crystallinity early in the decay process while decreasing total amounts of both crystalline and amorphous material. Data also showed an apparent decrease of approximately 0.05 A in the average spacing of the crystal planes in all degraded samples after roughly 20% weight loss, as well as a decrease in the average observed relative peak width at 2θ = 22.2°. These results may indicate a disruption of the outer most semi-crystalline cellulose chains comprising the wood microfibril. X-ray diffraction analysis of wood subjected to biological attack by Fungi may provide insight into degradative processes and wood cellulose structure.
-
Iron-reducing capacity of low-molecular-weight compounds produced in wood by Fungi
Holzforschung, 2006Co-Authors: Barry Goodell, Jody Jellison, Geoffrey Daniel, Yuhui QianAbstract:Birch and pine wood specimens were colonized by individual isolates of 12 Brown-Rot, 26 white-rot, six soft-rot and four blue (sap)-stain Fungi. Homogenized wood was subsequently extracted in 75% ethyl acetate and centrifuged. The filtered extracts were analyzed for their iron-reducing capabilities using a ferrozine-based assay. Agar fungal cultures were also examined directly using a spot test for iron reduction. Extracts from wood colonized by Brown-Rot Fungi showed significantly greater iron-reducing capability than extracts from wood colonized by white-rot or non-decay Fungi. Results of the spot test ratings were highly variable, but in general the greatest color responses were associated with the Brown-Rot cultures. The ability of Brown-Rot Fungi to produce compounds and/or modify the wood components that reduce iron is of relevance to the "chelator-mediated Fenton mechanism" that has been advanced as a theory for the non-enzymatic degradation of wood by Brown-Rot Fungi.
-
mechanisms of wood degradation by brown rot Fungi chelator mediated cellulose degradation and binding of iron by cellulose
Journal of Biotechnology, 2001Co-Authors: Barry GoodellAbstract:Abstract Iron, hydrogen peroxide, biochelators and oxalate are believed to play important roles in cellulose degradation by Brown-Rot Fungi. The effect of these compounds in an ‘enhanced’ Fenton system on α-cellulose degradation was investigated specifically in regard to molecular weight distribution and cellulose–iron affinity. This study shows that the degradative ability of an ultrafiltered low molecular weight preparation of chelating compounds isolated from the Brown-Rot fungus Gloeophyllum trabeum (termed ‘Gt chelator’) increased with increasing Gt chelator concentration when the FeIII to Gt chelator ratio was greater than about 30:1. When this ratio was less than 30:1, increasing Gt chelator concentration did not accelerate cellulose degradation. In excess hydrogen peroxide, cellulose degradation increased and then decreased with increasing iron concentration when FeIII was present in excess of the Gt chelator. The critical ratio of FeIII to Gt chelator varied depending on the concentration of hydrogen peroxide in the system. Increasing iron concentration above a critical iron:chelator ratio inhibited cellulose degradation. The optimum pH for cellulose degradation mediated by Gt chelator was around 4.0. A comparison of the effects of 2,3-DHBA (a chelator that reduces iron similarly to Gt chelator) and Gt chelator with respect to cellulose degradation demonstrated the same pattern of cellulose degradation. Cellulose–iron affinity studies were conducted at three pH levels (3.6, 3.8, 4.1), and the binding constants for cellulose–FeIII, cellulose–FeII and cellulose–FeIII in the presence of Gt chelator were calculated. The binding constants for cellulose–FeIII at all three pH levels were much higher than those for cellulose–FeII, and the binding constants for cellulose–FeIII in the presence of Gt chelator were very close to those for cellulose–FeII. This is probably the result of FeIII reduction to FeII by Gt chelator and suggests that chelators from the fungus may be able to sequester iron from cellulose and reduce it in near proximity to the cellulose and thereby better promote depolymerization. The free radical generating system described has potential for use in a variety of industrial processing and pollution control applications.
-
The role of cations in the biodegradation of wood by the brown rot Fungi
International Biodeterioration & Biodegradation, 1997Co-Authors: Jody Jellison, Jon H. Connolly, Barry Goodell, Brian Doyle, Barbara Illman, Frank A. Fekete, Andrea OstrofskyAbstract:This review describes what is presently known about the role of positively charged ions in the colonization and degradation of wood by brown rot Fungi. General patterns of cation accumulation and the roles of iron, manganese, calcium and other cations in the fungal environment are discussed. The physiology of brown rot Fungi and mechanisms of wood cell wall breakdown are emphasized.
