Myofibrillar cell wall extensions in the hyphal sheath of Postia placenta

1992 ◽  
Vol 38 (9) ◽  
pp. 905-911 ◽  
Author(s):  
Michael J. Larsen ◽  
Frederick Green III
Keyword(s):  
Cell Wall ◽  
Brown Rot ◽  
Decay Process ◽  
Structural Components ◽  
Hyphal Cell ◽  
Postia Placenta ◽  
Glass Cover ◽  
Hyphal Sheath ◽  
Brown Rot Decay ◽  
Extracellular Structures

Evidence is provided for the existence of linear extracellular fibrillar elements in the brown-rot fungus Postia placenta. These elements appear as structural components of the hyphal sheath and more closely resemble mycofibrils than fungal fimbriae. Mycofibrils are associated with and appear to originate from the hyphal surface when hyphae are grown on wood or inert substrates, such as glass cover slips and polycarbonate filters. These extracellular structures have a nominal diameter of 10–50 nm and are up to 25 μm in length. We conclude that mycofibrils are linear structural extensions of the hyphal cell wall. The precise function of mycofibrils in the brown-rot decay process of wood remains to be elucidated. Key words: Postia placenta, mycofibrils, fungal fimbriae, hyphal sheath, electron microscopy.

scholarly journals Mode of action of brown rot decay resistance in modified wood: a review

Holzforschung ◽  
2014 ◽  
Vol 68 (2) ◽  
pp. 239-246 ◽  
Author(s):  
Rebecka Ringman ◽  
Annica Pilgård ◽  
Christian Brischke ◽  
Klaus Richter
Keyword(s):  
Cell Wall ◽  
Mode Of Action ◽  
Wood Decay ◽  
Brown Rot ◽  
Decay Resistance ◽  
Hydroxyl Groups ◽  
Decay Fungi ◽  
Brown Rot Decay ◽  
Thermally Modified Wood ◽  
Modified Wood

Abstract Chemically or physically modified wood materials have enhanced resistance to wood decay fungi. In contrast to treatments with traditional wood preservatives, where the resistance is caused mainly by the toxicity of the chemicals added, little is known about the mode of action of nontoxic wood modification methods. This study reviews established theories related to resistance in acetylated, furfurylated, dimethylol dihydroxyethyleneurea-treated, and thermally modified wood. The main conclusion is that only one theory provides a consistent explanation for the initial inhibition of brown rot degradation in modified wood, that is, moisture exclusion via the reduction of cell wall voids. Other proposed mechanisms, such as enzyme nonrecognition, micropore blocking, and reducing the number of free hydroxyl groups, may reduce the degradation rate when cell wall water uptake is no longer impeded.

Études mycologique, entomologique et physico-chimique de troncs de Betula pendula en voie de dégradation. I. Répartition spatiale de l'état physico-chimique et de la mycoflore des troncs

1996 ◽  
Vol 74 (10) ◽  
pp. 1657-1664 ◽  
Author(s):  
Marie-Hélène Prince Sigrist ◽  
Daniel Job
Keyword(s):  
Fungal Biomass ◽  
Betula Pendula ◽  
Lignin Content ◽  
Brown Rot ◽  
Absorption Capacity ◽  
Decay Process ◽  
White Rot ◽  
Water Absorption Capacity ◽  
Decayed Wood ◽  
Brown Rot Decay

Decaying Betula pendula Roth trunks (measuring about 6 m in length) with brown rot or white rot were analyzed for the followings: stage of decay, wood structure, porosity, chemical composition of decayed wood, spatial distribution of fungal biomass, and mycoflora diversity. The fungal biomass in the trunks, although heterogeneous, is higher in white rot than in brown rot. As expected, the lignin/holocellulose ratio is higher in brown rot than in white rot (maximum 14.83 versus 0.67). Brown rot is generally more porous than white rot and presents a higher water absorption capacity but it retains less air. The results show that the basidiomycetes mycoflora is active in the white rot decay process. However it is not involved in the brown rot decay process because the wood is already much decayed (as much as 80% and more of lignin content). With the exception of moulds, the only mycoflora that could be isolated repetitively from the brown rot station was in fact pockets of white rot. Moreover, in brown rot, none of the epiflora matched the isolated endoflora. Keywords: white rot, brown rot, mycoflora, biomass.

Immuno-scanning electron microscopic localization of extracellular wood-degrading enzymes within the fibrillar sheath of the brown-rot fungus Postia placenta

1992 ◽  
Vol 38 (9) ◽  
pp. 898-904 ◽  
Author(s):  
Frederick Green III ◽  
Carol A. Clausen ◽  
Michael J. Larsen ◽  
Terry L. Highley
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Monoclonal Antibodies ◽  
Colloidal Gold ◽  
Brown Rot ◽  
Postia Placenta ◽  
Degrading Enzymes ◽  
Brown Rot Fungus ◽  
Hyphal Sheath ◽  
Scanning Electron

Extracellular wood-degrading enzymes of the brown-rot fungus Postia placenta were localized using colloidal gold labeled monoclonal antibodies to the β-1,4-xylanase (32 to 36 kDa) fraction of P. placenta. Postia placenta was grown from agar onto glass cover slips, immunolabeled with or without prior fixation, and examined by scanning electron microscopy. Enzymes were localized on the hyphal surface and on the clumped fibrillar elements mycofibrils of the hyphal sheath following fixation with glutaraldehyde. If fixation was omitted, labeling was diffuse and not localized on individual or clumped mycofibrils. We conclude that extracellular decay enzymes are weakly bound (noncovalently) to, but not identical with, the linear mycofibrillar elements of the hyphal sheath. The linear structural elements of the hyphal sheath may play an important role in transport and presentation of wood-degrading enzymes during the decay process. Key words: brown-rot fungi, enzymes, mycofibrils, hyphal sheath, immunolabeling, monoclonal antibodies, colloidal gold, scanning electron microscopy.

Mode of action of brown rot decay resistance of thermally modified wood: resistance to Fenton’s reagent

Holzforschung ◽  
2016 ◽  
Vol 70 (7) ◽  
pp. 691-697 ◽  
Author(s):  
Reza Hosseinpourpia ◽  
Carsten Mai
Keyword(s):  
Cell Wall ◽  
Brown Rot ◽  
Strength Loss ◽  
Decay Resistance ◽  
Fenton’S Reagent ◽  
Fenton's Reagent ◽  
Brown Rot Fungi ◽  
Brown Rot Decay ◽  
Wood Resistance ◽  
Fe Ions

Abstract The resistance of heat treated (HT) wood to brown rot fungi has been investigated, while the role of the Fenton reaction (FR) in the initial phase of degradation was in focus. Micro-veneers made of Scots pine, were HT with various intensities and their mass losses (MLHT) were determined before soaking with a solution of Fenton’s reagent containing Fe ions and hydrogen peroxide. The mass loss of the veneers treated that way (MLFT), their tensile strength loss (TSLFT) and the H2O2 decomposition were observed. The MLFT, TSLFT, and H2O2 loss decreased with increasing MLHT of the veneers. Soaking of the veneers in acetate buffer containing only Fe without H2O2 revealed that the heat treatment (HT) strongly reduces the Fe uptake by the cell walls. FTIR spectroscopy indicated oxidation of the unmodified control veneers but did not reveal predominant decay of cell wall components; the HT veneers were not changed at all due to FR. It was concluded that the reason for the enhanced resistance of HT wood to FR is attributable to hindered diffusion of Fe ions into the wood cell wall.

Mode of action of brown rot decay resistance in phenol-formaldehyde-modified wood: resistance to Fenton’s reagent

Holzforschung ◽  
2016 ◽  
Vol 70 (3) ◽  
pp. 253-259 ◽  
Author(s):  
Reza Hosseinpourpia ◽  
Carsten Mai
Keyword(s):  
Cell Wall ◽  
Mode Of Action ◽  
Fenton Reaction ◽  
Phenol Formaldehyde ◽  
Brown Rot ◽  
Weight Percent ◽  
Fenton’S Reagent ◽  
Fenton's Reagent ◽  
Brown Rot Decay ◽  
Modified Wood

Abstract The mode of action of phenol-formaldehyde (PF)-modified wood has been investigated with respect to its resistance to brown rot decay. The Fenton reaction is assumed to play a key role in the initial brown rot decay. Pine microveneers were modified to various weight percent gains (WPG) with low molecular weight PF and exposed to a solution containing Fenton’s reagent. The mass loss (ML) and tensile strength loss (TSL) as well as the decomposition of hydrogen peroxide within the incubation time decreased with the increasing WPG of the veneers. Incubation of untreated and PF-modified veneers in acetate buffer containing ferric ions without H2O2 revealed that the modification strongly reduces the uptake of iron by the wood cell wall. Further studies indicated that lignin promotes the decay of wood by Fenton’s reagent. The reason for the enhanced resistance of modified wood to the Fenton reaction is attributable to the impeded diffusion of iron ions into the cell wall rather than to the blocking of free phenolic sites of lignin, which accelerate redox cycling of iron.

Detection and Quantification of Oxalic Acid from the Brown-Rot Decay Fungus,Postia placenta

Holzforschung ◽  
1996 ◽  
Vol 50 (4) ◽  
pp. 312-318 ◽  
Author(s):  
C.R. Jordan ◽  
W.V. Dashek ◽  
T.L. Highley
Keyword(s):  
Oxalic Acid ◽  
Brown Rot ◽  
Decay Fungus ◽  
Postia Placenta ◽  
Brown Rot Decay ◽  
Detection And Quantification

New insight regarding mode of action of brown rot decay of modified wood based on DNA and gene expression studies: a review

2014 ◽  
Vol 6 (1) ◽  
pp. 5-7 ◽  
Author(s):  
G. Alfredsen ◽  
R. Ringman ◽  
A. Pilgård ◽  
C. G. Fossdal
Keyword(s):  
Gene Expression ◽  
Mode Of Action ◽  
Brown Rot ◽  
Expression Studies ◽  
Brown Rot Decay ◽  
Gene Expression Studies ◽  
Modified Wood

scholarly journals Natural durability and chemical composition of the Liquidambar sp. wood

FLORESTA ◽  
2020 ◽  
Vol 50 (2) ◽  
pp. 1179
Author(s):  
Thais Pereira Freitas ◽  
Juarez Benigno Paes ◽  
José Tarcísio Da Silva Oliveira ◽  
Walter Torezani Neto Boschetti ◽  
Déborah Nava Soratoo ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Brown Rot ◽  
Extractive Content ◽  
Natural Durability ◽  
Biological Origin ◽  
Postia Placenta ◽  
Nasutitermes Corniger ◽  
Moderate Resistance ◽  
Choice Feeding ◽  
Total Lignin

The wood is a material of biological origin and because of its chemical composition is subject to the attack of various organisms that use it as a source of food. Thus, this study aimed to evaluate the natural durability and chemical composition of the Liquidambar sp. wood. Were performed the accelerated laboratory test, with a pure culture of the Postia placenta fungus, causer of brown rot , and no choice-feeding of termites Nasutitermes corniger. After both tests, the samples were dried in an oven at 103 ± 2ºC until reaching constant mass and later weighed, to evaluate the percentage of mass loss. The contents of extractives, soluble, insoluble and total lignin, and holocellulose were also determined. The studied wood obtained losses of mass of 37.79% and 23.37%, when submitted to the action of fungus and termites, respectively, and an average extractive content equal to 4.13%. It is concluded that the Liquidambar sp. wood was moderate resistance to the attack of the brown rot fungus, and little resistant to the action of employed termites.

scholarly journals Contribution of the Cell Wall Component Teichuronopeptide to pH Homeostasis and Alkaliphily in the Alkaliphile Bacillus lentus C-125

1999 ◽  
Vol 181 (21) ◽  
pp. 6600-6606 ◽  
Author(s):  
Rikizo Aono ◽  
Masahiro Ito ◽  
Takayoshi Machida
Keyword(s):  
Cell Wall ◽  
Amino Acid Residues ◽  
Alkaline Ph ◽  
Structural Components ◽  
Chromosomal Dna ◽  
Ph Homeostasis ◽  
Cell Wall Component ◽  
Bacillus Lentus ◽  
Defective Mutant ◽  
Alkaline Conditions

ABSTRACT A teichuronopeptide (TUP) is one of major structural components of the cell wall of the facultative alkaliphilic strain Bacillus lentus C-125. A mutant defective in TUP synthesis grows slowly at alkaline pH. An upper limit of pH for growth of the mutant was 10.4, while that of the parental strain C-125 was 10.8. GenetupA, directing synthesis of TUP, was cloned from C-125 chromosomal DNA. The primary translation product of this gene is likely a cytoplasmic protein (57.3 kDa) consisting of 489 amino acid residues. Introduction of the tupA gene into the TUP-defective mutant complemented the mutation responsible for the pleiotropic phenotypes of the mutant, leading to simultaneous disappearance of the defect in TUP synthesis, the diminished ability for cytoplasmic pH homeostasis, and the low tolerance for alkaline conditions. These results demonstrate that the acidic polymer TUP in the cell wall plays a role in pH homeostasis in this alkaliphile.

Sign in / Sign up

Export Citation Format

Share Document