A Note on the Toxicity of Chloropicrin Vapors to Gloeophyllum Saepiarium and Poria sp. in Wood

Southern pine wafers infected with Gloeophyllum saepiarium and Poria sp. were exposed to a range of chloropicrin vapor concentrations for 4, 8, 12, 16, and 24 h. The minimum lethal dosages of chloropicrin for both fungi were determined at each exposure period. The range of lethal concentration/time values, calculated at each exposure period, was small for Poria sp. but much broader for G. saepiarium over the 24-h test limits. This difference indicates that increasing the length of exposure to chloropicrin has a greater affect on G. saepiarium (susceptibility increases) than on Poria sp. (susceptibility remains relatively constant)

Evaluation of Encapsulated and Gelled Chloropicrin Formulations for Use in Wood Poles

Gelling (increasing a fluid's viscosity) and encapsulation were evaluated as means to improve the handling properties of the fumigant chloropicrin during application in the remedial preservative treatment of poles and other timbers. Several gelling agents, at concentrations of < 5% (w/w), were capable of increasing the viscosity of chloropicrin above 100,000 centipoise. The form of the dispensed gel allowed for a reduced surface area during application (when compared to liquid chloropicrin) and volatility of the gelled formulation was effectively reduced. However, addition of gelling agents to chloropicrin did not reduce the relative volatility from equivalent exposed surface areas. An evaluation of methods for dispensing one gelled formulation identified a modified pressure cylinder as a means for safer and easier application of chloropicrin compared with currently used methods. Polymer tubes for encapsulation were also evaluated as a means of handling and dispensing both liquid and gelled chloropicrin

How Do Shipworms Eat Wood? Screening Shipworm Gill Symbiont Genomes for Lignin-Modifying Enzymes

Shipworms are ecologically and economically important mollusks that feed on woody plant material (lignocellulosic biomass) in marine environments. Digestion occurs in a specialized cecum, reported to be virtually sterile and lacking resident gut microbiota. Wood-degrading CAZymes are produced both endogenously and by gill endosymbiotic bacteria, with extracellular enzymes from the latter being transported to the gut. Previous research has predominantly focused on how these animals process the cellulose component of woody plant material, neglecting the breakdown of lignin - a tough, aromatic polymer which blocks access to the holocellulose components of wood. Enzymatic or non-enzymatic modification and depolymerization of lignin has been shown to be required in other wood-degrading biological systems as a precursor to cellulose deconstruction. We investigated the genomes of five shipworm gill bacterial symbionts obtained from the Joint Genome Institute Integrated Microbial Genomes and Microbiomes Expert Review for the production of lignin-modifying enzymes, or ligninases. The genomes were searched for putative ligninases using the Joint Genome Institute\u27s Function Profile tool and blastp analyses. The resulting proteins were then modeled using SWISS-MODEL. Although each bacterial genome possessed at least four predicted ligninases, the percent identities and protein models were of low quality and were unreliable. Prior research demonstrates limited endogenous ability of shipworms to modify lignin at the chemical/molecular level. Similarly, our results reveal that shipworm bacterial gill-symbiont enzymes are unlikely to play a role in lignin modification during lignocellulose digestion in the shipworm gut. This suggests that our understanding of how these keystone organisms digest and process lignocellulose is incomplete, and further research into non-enzymatic and/or other unknown mechanisms for lignin modification is required

Chloropicrin movement and fungitoxicity in decaying southern pine laminated timbers

Three groups of experiments were performed to determine an effective procedure for controlling decay in southern pine (Pinus spp.) laminated timbers. (i) A decaying laminated arch of southern pine was treated with chloropicrin. Movement of the chemical vapor through the arch and its effect on the decay and nondecay fungal population were monitored. (ii) Fungitoxicity studies with three decay fungi isolated from the laminated arch were performed by exposing infected wooden wafers to fumigant concentrations for various lengths of time, and by monitoring fumigant concentration and death of fungi in treated wooden blocks over a 24-hour period. (iii) Vapor movement across gluelines and along the radial and longitudinal axes of southern pine blocks conditioned to a range of moisture contents was monitored. Fungitoxic chloropicrin vapors diffused about 2 m from the treatment sites in the laminated arch over a 13-month period. A vapor wrap enclosing a portion of the arch limited escape of chloropicrin from the wood and improved treatment. Diffusion along the length of the arch was much greater than that between laminates. The minimum lethal dosages of chloropicrin determined in infected pine wafers ranged from 1.73 to 18.40 [mu]g hrs/ml for Gloeophyllum saepiarium and from 13.44 to 15.00 [mu]g hrs/ml for Poria sp., for 24 and 4 hour exposure periods respectively. Chloropicrin concentration/time values in wood blocks were maximized at 30 to 60% wood moisture content indicating that treatment may be more effective at this moisture content range than at 8%. Movement radially through wood and across gluelines was severely limited when compared to longitudinal movement. The rate of chloropicrin diffusion through wood blocks decreased with increasing severity of incipient decay. Minimum lethal dosages of chloropicrin to decay fungi were higher in infected wood blocks than in infected wafers. The findings of this research support the following recommendations: (i) Decay may be controlled by treatment with 0.5 cc of chloropicrin per square centimeter of cross sectional area at appropriately spaced intervals along the timber. (ii) Treatment sites should be spaced at about 2 m intervals along the decayed length of the timber for wood at about 8% moisture content. Treatment sites should be spaced closer together for wood of higher moisture contents. (iii) Treatment holes should contact all laminates. (iv) A vapor barrier should be employed to retain fumigant vapors in the timber

Bound Chlorinated Residue in Chloropicrin-Treated Douglas-Fir

Douglas-fir wafers exposed to chloropicrin vapors, then aerated and heated or extracted with acetone, were analyzed under a scanning electron microscope equipped with an energy dispersive X-ray analyzer. Chlorinated residues appeared to be most concentrated in the middle lamellae and in areas where wood extractives were located, which indicates that the residues were selectively binding to phenolic materials. Thin layer chromatography of acetone extracts of the treated wood suggested that chlorinated residues were binding to extractives, particularly to a portion of the phenolic extractive dihydro-quercetin. Analysis of a mixture of vanillin (a phenolic lignin derivative) and chloropicrin showed the presence of two other compounds. Mass spectroscopy tentatively identified these as CCl3-vanillin and NO2-vanillin. This identification suggests that the chloropicrin molecule was fragmented and that the two components were chemically linked to the vanillin molecule at an unspecified point. The data suggest an explanation for the presence of a phenolic-bound chlorinated residue in chloropicrin-treated wood

Transcriptome analysis of the brown rot fungus \u3cem\u3eGloeophyllum trabeum\u3c/em\u3e during lignocellulose degradation

Brown rot fungi have great potential in biorefinery wood conversion systems because they are the primary wood decomposers in coniferous forests and have an efficient lignocellulose degrading system. Their initial wood degradation mechanism is thought to consist of an oxidative radical-based system that acts sequentially with an enzymatic saccharification system, but the complete molecular mechanism of this system has not yet been elucidated. Some studies have shown that wood degradation mechanisms of brown rot fungi have diversity in their substrate selectivity. Gloeophyllum trabeum, one of the most studied brown rot species, has broad substrate selectivity and even can degrade some grasses. However, the basis for this broad substrate specificity is poorly understood. In this study, we performed RNA-seq analyses on G. trabeum grown on media containing glucose, cellulose, or Japanese cedar (Cryptomeria japonica) as the sole carbon source. Comparison to the gene expression on glucose, 1,129 genes were upregulated on cellulose and 1,516 genes were upregulated on cedar. Carbohydrate Active enZyme (CAZyme) genes upregulated on cellulose and cedar media by G. trabeum included glycoside hyrolase family 12 (GH12), GH131, carbohydrate esterase family 1 (CE1), auxiliary activities family 3 subfamily 1 (AA3_1), AA3_2, AA3_4 and AA9, which is a newly reported expression pattern for brown rot fungi. The upregulation of both terpene synthase and cytochrome P450 genes on cedar media suggests the potential importance of these gene products in the production of secondary metabolites associated with the chelator-mediated Fenton reaction. These results provide new insights into the inherent wood degradation mechanism of G. trabeum and the diversity of brown rot mechanisms

Furfurylated wood: impact on Postia placenta gene expression and oxalate crystal formation

Modified wood can provide protection against a range of wood deteriorating organisms. Several hypotheses have been put forward regarding the protection mechanisms against wood decaying fungi including fungal enzyme inefficiency due to non-recognition, lower micropore size, and insufficient wood moisture content. The aim of this study was to obtain new insight into the protection manner of furfuryl alcohol (FA) modified Scots pine sapwood (WFA), and to examine biochemical mechanisms and adaptive changes in gene expression utilised by Postia placenta during early colonisation of WFA. Samples were harvested after 2, 4, and 8 weeks of incubation. After 8 weeks, the mass loss (0.1%) and wood moisture content (21.0%) was lower inWFA, than in non-modified Scots pine sapwood samples (W), 26.1% and 46.1%, respectively. Microscopy revealed needle-shaped calcium oxalate crystals, at all harvesting points, most prominently present after 4 and 8 weeks, and only in the WFA samples. Among the findings based on gene profiles were indications of a possible shift toward increased expression, or at least no down regulation, of genes related to oxidative metabolism and concomitant reduction of several genes related to the breakdown of polysaccharides in WFA compared to W.publishedVersio

Outlook for tuberculosis elimination in California: An individual-based stochastic model.

RationaleAs part of the End TB Strategy, the World Health Organization calls for low-tuberculosis (TB) incidence settings to achieve pre-elimination (&lt;10 cases per million) and elimination (&lt;1 case per million) by 2035 and 2050, respectively. These targets require testing and treatment for latent tuberculosis infection (LTBI).ObjectivesTo estimate the ability and costs of testing and treatment for LTBI to reach pre-elimination and elimination targets in California.MethodsWe created an individual-based epidemic model of TB, calibrated to historical cases. We evaluated the effects of increased testing (QuantiFERON-TB Gold) and treatment (three months of isoniazid and rifapentine). We analyzed four test and treat targeting strategies: (1) individuals with medical risk factors (MRF), (2) non-USB, (3) both non-USB and MRF, and (4) all Californians. For each strategy, we estimated the effects of increasing test and treat by a factor of 2, 4, or 10 from the base case. We estimated the number of TB cases occurring and prevented, and net and incremental costs from 2017 to 2065 in 2015 U.S. dollars. Efficacy, costs, adverse events, and treatment dropout were estimated from published data. We estimated the cost per case averted and per quality-adjusted life year (QALY) gained.Measurements and main resultsIn the base case, 106,000 TB cases are predicted to 2065. Pre-elimination was achieved by 2065 in three scenarios: a 10-fold increase in the non-USB and persons with MRF (by 2052), and 4- or 10-fold increase in all Californians (by 2058 and 2035, respectively). TB elimination was not achieved by any intervention scenario. The most aggressive strategy, 10-fold in all Californians, achieved a case rate of 8 (95% UI 4-16) per million by 2050. Of scenarios that reached pre-elimination, the incremental net cost was $20 billion (non-USB and MRF) to$48 billion. These had an incremental cost per QALY of $657,000 to$3.1 million. A more efficient but somewhat less effective single-lifetime test strategy reached as low as $80,000 per QALY.ConclusionsSubstantial gains can be made in TB control in coming years by scaling-up current testing and treatment in non-USB and those with medical risks

Acquisition of Advanced Engineered Wood Composites Manufacturing and Science Laboratory

This action is in response to the Major Research Instrumentation Initiative MRI\u2798 (NSF-98-16). The purpose is to upgrade a Composite-Reinforced-Wood (CRW) Manufacturing Science Laboratory at the University of Maine. The laboratory is part of a new facility designed to develop the next generation of wood composites for construction. Recent research has shown that Composite Reinforced Wood (CRW) offers superior properties at reduced costs. As in the development of reinforced and prestressed concrete, basic research is needed to unlock the full potential of a wide variety of CRW structural members, e.g. joists, beams, columns, panel and connections. CRW hybrids are unique in that two very different classes of material, FRP and wood are used together; thus the principles governing the short and long-term structural behavior differ in many ways form those involving only one of the two materials. This project will focus on:Developing a new class of FRP reinforcing materials that are compatible with wood, particularly its hypoexpansion and visco-elastic properties.Developing and maintaining over time the interface (bond) between the two materials needed to ensure full composite action (this will require a basic understanding of the mechanisms of bond durability).Developing a basic understanding of the short and long-term behavior of CRW structural elements including performance over the full range of loading, ultimate strength, ductility, creep, fatigue, and moisture/temperature/UV cycling.The research is conducted at four different levels: micro, meso, macro and structural. A multi-disciplinary team will conduct the research composing ten engineers and scientists from three units at the University of Maine (civil/structural engineering, wood science and technology, and chemical engineering), the industry-supported SPI composites Institute, the Composites Materials Engineering Center (COMTEC) in Winona MN, and the USDA Forest Products laboratory in Madison

Lignocellulose degradation mechanisms across the Tree of Life.

Organisms use diverse mechanisms involving multiple complementary enzymes, particularly glycoside hydrolases (GHs), to deconstruct lignocellulose. Lytic polysaccharide monooxygenases (LPMOs) produced by bacteria and fungi facilitate deconstruction as does the Fenton chemistry of brown-rot fungi. Lignin depolymerisation is achieved by white-rot fungi and certain bacteria, using peroxidases and laccases. Meta-omics is now revealing the complexity of prokaryotic degradative activity in lignocellulose-rich environments. Protists from termite guts and some oomycetes produce multiple lignocellulolytic enzymes. Lignocellulose-consuming animals secrete some GHs, but most harbour a diverse enzyme-secreting gut microflora in a mutualism that is particularly complex in termites. Shipworms however, house GH-secreting and LPMO-secreting bacteria separate from the site of digestion and the isopod Limnoria relies on endogenous enzymes alone. The omics revolution is identifying many novel enzymes and paradigms for biomass deconstruction, but more emphasis on function is required, particularly for enzyme cocktails, in which LPMOs may play an important role.The work of the teams at York, Portsmouth and Cambridge on development of ideas expressed in this review was supported by grants from BBSRC (BB/H531543/1, BB/L001926/1, BB/1018492/1, BB/K020358/1). The workshop was supported by a US Partnering grant from BBSRC (BB/G016208/1) to Cragg and a BBSRC/FAPESP grant to Bruce (BB/1018492/1). Watts was supported by Marie Curie FP7-RG 276948. Goodell acknowledges support from USDA Hatch Project S-1041 VA-136288. Distel acknowledges support from NSF Award IOS1442759 and NIH Award Number U19 TW008163. Beckham thanks the US Department of Energy Bioenergy Technologies Office for funding. We appreciated the hospitality of the Linnean Society in allowing us to meet in inspirational surroundings under portraits of Linnaeus, Darwin and Wallace.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.cbpa.2015.10.01