Conditions for soft rot of wood

1991 ◽  
Vol 37 (11) ◽  
pp. 869-874 ◽  
Author(s):  
J. J. Worrall ◽  
S. E. Anagnost ◽  
C. J. K. Wang
Keyword(s):  
Weight Loss ◽  
Wood Decay ◽  
Soft Rot ◽  
Experimental Conditions ◽  
Optimal Development ◽  
Weight Losses ◽  
Nylon Mesh ◽  
Petri Dishes ◽  
Moisture Conditions

Conditions leading to optimal development of soft rot of wood were studied in vitro. Rates of weight loss generally remained more or less constant for 12 weeks, after which they decreased. Use of Petri dishes as decay chambers, saturation of blocks with a reduced nutrient solution containing micronutrients and vitamins, and use of a thick nylon mesh as a support between the agar and blocks generally gave better results than alternative conditions. Depending on experimental conditions, decay was either superficial or more or less uniform throughout the block. The uniform pattern was associated with higher weight losses than the superficial pattern. These and other results suggest that, although soft rot is most readily apparent as a surface decay of near-saturated wood in service, moisture conditions for optimal development may be no different than for decays caused by basidiomycetes. Key words: wood decay, moisture, Chaetomium globosum.

Importance and mobilization of nutrients in soft rot of wood

1991 ◽  
Vol 37 (11) ◽  
pp. 864-868 ◽  
Author(s):  
James J. Worrall ◽  
C. J. K. Wang
Keyword(s):  
Weight Loss ◽  
Key Words ◽  
Wood Decay ◽  
External Solution ◽  
Soft Rot ◽  
Chaetomium Globosum ◽  
Nutrient Concentrations ◽  
Nutrient Requirements ◽  
Low Levels ◽  
Scytalidium Lignicola

Soft rot of wood by Chaetomium globosum and Scytalidium lignicola was negligible in the absence of added nutrients. Independently varying the concentrations of nutrients in double Abrams' solution (which is often used for testing soft rot of wood) showed that these concentrations are higher than necessary, and in some cases supraoptimal, for soft rot as measured by weight loss. Optimal nutrient concentrations were lower in cases of low decay capacity than in cases of high decay capacity. A suitable, reduced solution contained, per litre, 1.5 g NH4NO3, 2.5 g KH2PO4, 2.0 g K2HPO4, and 1 g MgSO4∙7H2O. Best results were obtained when blocks were infiltrated with the solution. Increasing osmolality with KCl inhibited soft rot, suggesting that the solution satisfies specific nutrient requirements rather than an osmophilic requirement. P and especially N were actively mobilized into decaying blocks. As any of the nutrients were added at low levels to the external solution, decay and the influx of N increased. Key words: wood decay, soft rot, nutrients, translocation, osmophily.

scholarly journals Relative In Vitro Wood Decay Resistance of Sapwood from Landscape Trees of Southern Temperate Regions

HortScience ◽  
2010 ◽  
Vol 45 (3) ◽  
pp. 401-408 ◽  
Author(s):  
Manuela Baietto ◽  
A. Dan Wilson
Keyword(s):  
Weight Loss ◽  
Wood Decay ◽  
Dry Weight ◽  
Decay Resistance ◽  
Decay Rates ◽  
Heterobasidion Annosum ◽  
Decay Fungi ◽  
Wood Decay Fungi ◽  
Landscape Trees

The development of wood decay caused by 12 major root-rot and trunk-rot fungi was investigated in vitro with sapwood extracted from nine ornamental and landscape hardwood and conifer species native to southern temperate regions of North America, Europe, and the lower Mississippi Delta. Wood decay rates based on dry weight loss for 108 host tree–wood decay fungi combinations were compared at 21 °C over 1-year and 2-year incubation periods in the absence of tree-resistance mechanisms. Strains of Armillaria mellea, Ganoderma lucidum, and Heterobasidion annosum exhibited the highest decay potential in most tree species tested. The order of fungi causing the greatest decay varied over time as a result of temporal changes in decay-rate curves. Relative wood durability or resistance to decay generally was greater in gymnosperm than in angiosperm wood types. Quercus nuttallii, Fraxinus pennsylvanica, and Quercus lyrata sustained the highest levels of decay by all fungi. Northern white cedar (Thuja occidentalis) sapwood was most resistant to decay by all rot-fungi tested, sustaining only limited weight loss after 1 and 2 years of decay, although sapwood of Pinus taeda, Liquidambar styraciflua, and Platanus occidentalis had relatively low levels of decay after 2 years. These results in combination with data from portable decay-detection devices provide useful information for the management of tree breakages or failures resulting from wood decay fungi in hazardous landscape trees. Some potential landscaping applications for tree evaluations, risk assessments, and selections for tree-replacement plantings are discussed.

scholarly journals Decaying hardwood associated fungi showing signatures of polyethylene degradation

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 7056-7070
Author(s):  
Prameesha Perera ◽  
Anushi Suwanethya Deraniyagala ◽  
Maduri Piumi Sashikala Mahawaththage ◽  
Harshini Herath ◽  
Chandima Shashikala Kumari Rajapakse ◽  
...  
Keyword(s):  
Weight Loss ◽  
Tensile Properties ◽  
Structural Characteristics ◽  
Schizophyllum Commune ◽  
Wood Decay ◽  
Nuclear Ribosomal Dna ◽  
Percent Reduction ◽  
Internal Transcribed Spacer Region ◽  
Decay Fungi

The involvement of wood decay fungi and the importance of their enzymes in polyethylene degradation is well documented. Therefore, decay-resistant hardwood associated fungi should be better degraders with their versatile enzymatic systems. In the current study, decaying hardwood associated fungi were isolated and their ability to degrade low-density polyethylene (LDPE) was assessed. Thirty-three isolates were identified by sequencing the internal transcribed spacer region of nuclear ribosomal DNA. Randomly selected isolates were tested for laccase producing abilities. Three species were selected to test their potentials in LDPE sheet degradation. Fungi were incubated in Czapek-Dox broth containing 20-micron LDPE sheets at room temperature for 60 days. The biodegradation signatures were assessed by analyzing the changes in structural characteristics of LDPE using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), percent reduction of tensile properties, and weight loss. FTIR analysis revealed changes in certain functional groups compared with the control, indicating chemical changes resulting from the treatment. LDPE sheets incubated with fungi showed cracks and holes under SEM analysis, percent reduction in tensile properties, and weight loss, which are the signatures of degradation. This study revealed that the hardwood decaying basidiomycetes, Phlebiopsis flavidoalba, Schizophyllum commune, and Phanerodontia chrysosporium have the potential for in vitro LDPE degradation.

Hydrolytic and Color Stability of Resin Infiltration: A Preliminary in vitro Trial

2016 ◽  
Vol 17 (5) ◽  
pp. 377-381 ◽  
Author(s):  
Priyanshi Ritwik ◽  
Christopher M Jones ◽  
Yuwei Fan ◽  
Nikhil K Sarkar
Keyword(s):  
Weight Loss ◽  
Color Change ◽  
Color Stability ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Resin Infiltration ◽  
Dental Sealant ◽  
Group 3 ◽  
Group 2

ABSTRACT Aims Resin infiltration is an emerging technique for management of noncavitated lesions. This study evaluated the in vitro hydrolytic and color stability of the ICON® resin infiltration system (IC) in 42 extracted human teeth. Materials and methods ICON® resin infiltration system was compared with dental adhesive (DA) and dental sealant (DS). The products were applied according to manufacturer's instructions. The baseline weight and color of the samples were recorded. Color was recorded by spectoral colorimeter. The samples were subjected to four experimental conditions: (1) group 1: Stored in lactic acid solution (pH 4.9) for 24 hours; (2) group 2: Thermocycled for 100 cycles (temperatures: 5°C, 55°C, and dwell time of 15 seconds); (3) group 3: Stored in 0.1 N sodium hydroxide solution (pH 12.48) for 14 days at 60°C; (4) group 4: Stored in phosphate-buffered saline solution (pH 7.2) at 37°C for 4 months. The weight and color were recorded again after removal of the samples from the experimental conditions. Two-factor analysis of variance models and Tukey's Honestly Significant Difference were performed to assess statistical differences among the groups. Scanning electron microscopy imaging was performed for samples from groups 1, 3, and 4. Results All the samples showed loss of material and change in color. In the demineralizing solution, IC showed significantly greater weight loss (p = 0.032) and color change (p = 0.038) compared with DA. Dental Sealant showed significantly greater weight loss than IC (p = 0.027) after thermocycling. Teeth in group 3 exhibited the greatest weight loss (p < 0.001). Teeth in group 2 exhibited the greatest color change (p < 0.001). Conclusion All tested materials showed loss of retention and color change in the experimental conditions. Infiltration system exhibited greatest weight loss and color change in demineralizing solution. Dental sealant exhibited greatest weight loss upon thermocycling. Clinical significance Clinicians should be cautious about the limitations of retention and color stability when considering resin infiltration for incipient lesions. How to cite this article Ritwik P, Jones CM, Fan Y, Sarkar NK. Hydrolytic and Color Stability of Resin Infiltration: A Preliminary in vitro Trial. J Contemp Dent Pract 2016;17(5):377-381.

Chitin as an indicator of the biomass of two wood-decay fungi in relation to temperature, incubation time, and media composition

1998 ◽  
Vol 44 (6) ◽  
pp. 575-581 ◽  
Author(s):  
Kent Nilsson ◽  
Jonny Bjurman
Keyword(s):  
Weight Loss ◽  
Wood Decay ◽  
Brown Rot ◽  
Dry Weight ◽  
Soft Rot ◽  
Dry Mass ◽  
Malt Extract ◽  
Decay Fungi ◽  
Chitin Content ◽  
Wood Decay Fungi

Cell wall chitin was determined in the mycelia of the brown rot fungus Neolentinus lepideus (Lentinus lepideus) and an isolate of the soft rot fungus Phialophora sp. to study the correlation to mycelial dry mass. The fungi were incubated as liquid cultures for three incubation periods at three temperatures in six nutrient media with varying levels and combinations of carbon and nitrogen. The glucosamine yield was found to be maximized by hydrolysis at 90°C for 48 h. The chitin content in the studied fungi varied from 8.3 to 39.8 μg.mg-1for N. lepideus and 7.7 to 46 μg.mg-1for the Phialophora isolate. The chitin concentration was remarkably constant, about 10 μg.mg-1, in mycelia growing on the low nitrogen malt extract medium. An experiment with wood blocks indicated that chitin may be a good marker for total fungal biomass production, including living and dead mycelia, in early stages of wood decay (dry weight loss <6%). At higher dry weight losses, the chitin content reaches a plateau or decreases despite continuing degradation as determined by the dry weight loss. The chitin content of visible mycelia growing on wood was determined for both fungi and found to be 19.1 and 12.9 μg.mg-1for N. lepideus and the Phialophora isolate, respectively.Key words: chitin, wood-decay fungi, utility poles, brown rot, soft rot, glucosamine, colorimetry.

scholarly journals In Vitro Hypoxia Responsiveness Of Fdg And Faza Retention: Influence Of Shaking Versus Stagnant Conditions, Glass Versus Polystyrene Substrata And Cell Number Down-Scaling

2020 ◽  
Author(s):  
Morten Busk ◽  
Michael R Horsman ◽  
Jens Overgaard ◽  
Steen Jakobsen
Keyword(s):  
Single Photon ◽  
Photon Emission ◽  
Cell Number ◽  
Medium Composition ◽  
Emission Computed Tomography ◽  
Experimental Conditions ◽  
Positron Emission ◽  
Orbital Shaking ◽  
Petri Dishes

Abstract Background. In vitro experiments using radiolabeled molecules is fundamental for Positron emission tomography (PET) or single photon emission computed tomography (SPECT) tracer development and various metabolic assays, but no consensus on appropriate incubation conditions exists. Specifically, the use of shaking versus non-shaking conditions, cell number to medium volume and the choice of cell plating material may unintentionally influence cellular oxygenation and medium composition. This is problematic when testing the oxygen-dependence of tracers including 18F-fluoro-2-deoxyglucose (FDG) and hypoxia-selective 2-nitroimidazoles (e.g., 18F-fluoroazomycin-arabinoside, FAZA) or when doing prolonged experiments. The purpose of this study was to assess the influence of various experimental conditions on tracer retention. Methods. Tumor cells were seeded in a) Glass or standard Polystyrene Petri dishes or as b) discrete droplets in polystyrene Petri dishes or on 9 mm glass coverslips positioned in glass Petri dishes. When confluent, cells were pre-equilibrated for 2h to 21%, 0.5% or 0% O2 and FDG or FAZA was added, followed by cell harvest and analysis of radioactivity 1h (FDG) or 3h (FAZA) after. Experiments were conducted with/without orbital shaking. Results. The influence of hypoxia on tracer retention varied widely among cell lines, but shaking-induced convection did not influence uptake. In contrast, hypoxia-driven FAZA, and to some extent FDG, retention was much lower in cells grown on polyethylene than glass. Scaling-down the number of cells did not compromise accuracy. Conclusions. Most experiments can be performed appropriately in the absence of shaking and with downscaling of cell number but the use of conventional plasticware is highly problematic for studies on tracers and drugs that are metabolized and retained or activated at low O2 levels.

scholarly journals In Vitro Hypoxia Responsiveness Of Fdg And Faza Retention: Influence Of Shaking Versus Stagnant Conditions, Glass Versus Polystyrene Substrata And Cell Number Down-Scaling

2020 ◽  
Author(s):  
Morten Busk ◽  
Michael R Horsman ◽  
Jens Overgaard ◽  
Steen Jakobsen
Keyword(s):  
Single Photon ◽  
Photon Emission ◽  
Cell Number ◽  
Medium Composition ◽  
Emission Computed Tomography ◽  
Experimental Conditions ◽  
Positron Emission ◽  
Orbital Shaking ◽  
Petri Dishes

Abstract Background. In vitro experiments using radiolabeled molecules is fundamental for Positron emission tomography (PET) or single photon emission computed tomography (SPECT) tracer development and various metabolic assays, but no consensus on appropriate incubation conditions exists. Specifically, the use of shaking versus non-shaking conditions, cell number to medium volume and the choice of cell plating material may unintentionally influence cellular oxygenation and medium composition. This is problematic when testing the oxygen-dependence of tracers including 18F-fluoro-2-deoxyglucose (FDG) and hypoxia-selective 2-nitroimidazoles (e.g., 18F-fluoroazomycin-arabinoside, FAZA) or when doing prolonged experiments. The purpose of this study was to assess the influence of various experimental conditions on tracer retention. Methods. Tumor cells were seeded in a) Glass or standard Polystyrene Petri dishes or as b) discrete droplets in polystyrene Petri dishes or on 9 mm glass coverslips positioned in glass Petri dishes. When confluent, cells were pre-equilibrated for 2h to 21%, 0.5% or 0% O2 and FDG or FAZA was added, followed by cell harvest and analysis of radioactivity 1h (FDG) or 3h (FAZA) after. Experiments were conducted with/without orbital shaking. Results. The influence of hypoxia on tracer retention varied widely among cell lines, but shaking-induced convection did not influence uptake. In contrast, hypoxia-driven FAZA, and to some extent FDG, retention was much lower in cells grown on polyethylene than glass. Scaling-down the number of cells did not compromise accuracy. Conclusions. Most experiments can be performed appropriately in the absence of shaking and with downscaling of cell number but the use of conventional plasticware is highly problematic for studies on tracers and drugs that are metabolized and retained or activated at low O2 levels.

scholarly journals In Vitro Hypoxia Responsiveness of [18F]FDG and [18F]FAZA Retention: Influence of Shaking Versus Stagnant Conditions, Glass Versus Polystyrene Substrata and Cell Number Down-Scaling

2020 ◽  
Author(s):  
Morten Busk ◽  
Michael R Horsman ◽  
Jens Overgaard ◽  
Steen Jakobsen
Keyword(s):  
Single Photon ◽  
Photon Emission ◽  
Cell Number ◽  
Medium Composition ◽  
Emission Computed Tomography ◽  
Experimental Conditions ◽  
Positron Emission ◽  
Orbital Shaking ◽  
Petri Dishes

Abstract Background. In vitro experiments using radiolabeled molecules is fundamental for Positron emission tomography (PET) or single photon emission computed tomography (SPECT) tracer development and various metabolic assays, but no consensus on appropriate incubation conditions exists. Specifically, the use of shaking versus non-shaking conditions, cell number to medium volume and the choice of cell plating material may unintentionally influence cellular oxygenation and medium composition. This is problematic when testing the oxygen-dependence of tracers including 18F-fluoro-2-deoxyglucose ([18F]FDG) and hypoxia-selective 2-nitroimidazoles (e.g., 18F-fluoroazomycin-arabinoside, [18F]FAZA) or when doing prolonged experiments. The purpose of this study was to assess the influence of various experimental conditions on tracer retention. Methods. Tumor cells were seeded in a) Glass or standard Polystyrene Petri dishes or as b) discrete droplets in polystyrene Petri dishes or on 9 mm glass coverslips positioned in glass Petri dishes. When confluent, cells were pre-equilibrated for 2h to 21%, 0.5% or 0% O2 and [18F]FDG or [18F]FAZA was added, followed by cell harvest and analysis of radioactivity 1h ([18F]FDG) or 3h ([18F]FAZA) after. Experiments were conducted with/without orbital shaking. Results. The influence of hypoxia on tracer retention varied widely among cell lines, but shaking-induced convection did not influence uptake. In contrast, hypoxia-driven [18F]FAZA, and to some extent [18F]FDG, retention was much lower in cells grown on polyethylene than glass. Scaling-down the number of cells did not compromise accuracy. Conclusions. Tracer retention was similar under stagnant and forced convection conditions suggesting that the former approach may be appropriate even when accurate control of oxygen and tracer availability is required. In contrast, conventional plasticware should be used with caution when studying tracers and drugs that are metabolized and retained or activated at low O2 levels. Downscaling of cell number, by reducing the effective growth area, was feasible, without compromising accuracy.

Observations of Frozen-Hydrated Microtubules

1990 ◽  
Vol 48 (1) ◽  
pp. 504-505
Author(s):  
D. Chrétien ◽  
D. Job ◽  
R.H. Wade
Keyword(s):  
Fourier Transforms ◽  
Structural Complexity ◽  
Image Contrast ◽  
Phase Behaviour ◽  
Experimental Conditions ◽  
Thin Sections ◽  
Surface Lattice ◽  
Cilia And Flagella ◽  
Outstanding Question

Microtubules are filamentary structures found in the cytoplasm of eukaryotic cells, where, together with actin and intermediate filaments, they form the components of the cytoskeleton. They have many functions and show various levels of structural complexity as witnessed by the singlet, doublet and triplet structures involved in the architecture of centrioles, basal bodies, cilia and flagella. The accepted microtubule model consists of a 25 nm diameter hollow tube with a wall made up of 13 paraxial protofilaments (pf). Each pf is a string of aligned tubulin dimers. Some results have suggested that the pfs follow a superhelix. To understand how microtubules function in the cell an accurate model of the surface lattice is one of the requirements. For example the 9x2 architecture of the axoneme will depend on the organisation of its component microtubules. We should also note that microtubules with different numbers of pfs have been observed in thin sections of cellular and of in-vitro material. An outstanding question is how does the surface lattice adjust to these different pf numbers?We have been using cryo-electron microscopy of frozen-hydrated samples to study in-vitro assembled microtubules. The experimental conditions are described in detail in this reference. The results obtained in conjunction with thin sections of similar specimens and with axoneme outer doublet fragments have already allowed us to characterise the image contrast of 13, 14 and 15 pf microtubules on the basis of the measured image widths, of the the image contrast symmetry and of the amplitude and phase behaviour along the equator in the computed Fourier transforms. The contrast variations along individual microtubule images can be interpreted in terms of the geometry of the microtubule surface lattice. We can extend these results and make some reasonable predictions about the probable surface lattices in the case of other pf numbers, see Table 1. Figure 1 shows observed images with which these predictions can be compared.

Superoxide, Xanthine Oxidase and Platelet Reactions: Further Studies on Mechanisms by which Oxidants Influence Platelets

1981 ◽  
Vol 45 (03) ◽  
pp. 290-293 ◽  
Author(s):  
Peter H Levine ◽  
Danielle G Sladdin ◽  
Norman I Krinsky
Keyword(s):  
Superoxide Dismutase ◽  
Cytochrome C ◽  
Xanthine Oxidase ◽  
Direct Effect ◽  
Platelet Function ◽  
Experimental Conditions ◽  
Release Reaction

SummaryIn the course of studying the effects on platelets of the oxidant species superoxide (O- 2), Of was generated by the interaction of xanthine oxidase plus xanthine. Surprisingly, gel-filtered platelets, when exposed to xanthine oxidase in the absence of xanthine substrate, were found to generate superoxide (O- 2), as determined by the reduction of added cytochrome c and by the inhibition of this reduction in the presence of superoxide dismutase.In addition to generating Of, the xanthine oxidase-treated platelets display both aggregation and evidence of the release reaction. This xanthine oxidase induced aggreagtion is not inhibited by the addition of either superoxide dismutase or cytochrome c, suggesting that it is due to either a further metabolite of O- 2, or that O- 2 itself exerts no important direct effect on platelet function under these experimental conditions. The ability of Of to modulate platelet reactions in vivo or in vitro remains in doubt, and xanthine oxidase is an unsuitable source of O- 2 in platelet studies because of its own effects on platelets.

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