scholarly journals Effect of Phenol Formaldehyde Resin Penetration on the Quasi-Static and Dynamic Mechanics of Wood Cell Walls Using Nanoindentation

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1409 ◽  
Author(s):  
Xinzhou Wang ◽  
Xuanzong Chen ◽  
Xuqin Xie ◽  
Zhurun Yuan ◽  
Shaoxiang Cai ◽  
...  
Keyword(s):  
Cell Walls ◽  
Laser Scanning ◽  
Phenol Formaldehyde ◽  
Phenol Formaldehyde Resin ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Formaldehyde Resin ◽  
Masson Pine ◽  
Crystallinity Degree ◽  
Modified Wood

To evaluate the effects of phenol formaldehyde (PF) resin modification on wood cell walls, Masson pine (Pinus massoniana Lamb.) wood was impregnated with PF resin at the concentrations of 15%, 20%, 25%, and 30%, respectively. The penetration degree of PF resin into wood tracheids was quantitatively determined using confocal laser scanning microscopy (CLSM). The micromechanical properties of the control and PF-modified wood cell walls were then analyzed by the method of quasi-static nanoindentation and dynamic modulus mapping techniques. Results indicated that PF resin with low molecular weight can penetrate deeply into the wood tissues and even into the cell walls. However, the penetration degree decreased accompanying with the increase of penetration depth in wood. Both the quasi-static and dynamic mechanics of wood cell walls increased significantly after modification by the PF resin at the concentration less than 20%. The cell-wall mechanics maintained stable and even decreased as the resin concentration was increased above 20%, resulting from the increasing bulking effects such as the decreased crystallinity degree of cellulose. Furthermore, the mechanics of cell walls in the inner layer was lower than that in the outer layer of PF-modified wood.

scholarly journals The MNN2 Gene Knockout Modulates the Antifungal Resistance of Biofilms of Candida glabrata

Biomolecules ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 130 ◽  
Author(s):  
Celia F. Rodrigues ◽  
Diana Vilas Boas ◽  
Ken Haynes ◽  
Mariana Henriques
Keyword(s):  
Cell Walls ◽  
Candida Glabrata ◽  
Laser Scanning ◽  
Reference Strain ◽  
Gene Knockout ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Drug Treatments ◽  
Biomass Reduction ◽  
Biofilm Matrix

Candida glabrata biofilms are recognized to have high resistance to antifungals. In order to understand the effect of mannans in the resistance profile of C. glabrata mature biofilms, C. glabrata Δmnn2 was evaluated. Biofilm cell walls were analysed by confocal laser scanning microscopy (CLSM) and their susceptibility was assessed for fluconazole, amphotericin B, caspofungin, and micafungin. Crystal violet and Alcian Blue methods were performed to quantify the biomass and the mannans concentration in the biofilm cells and matrices, respectively. The concentration of β-1,3 glucans was also measured. No visible differences were detected among cell walls of the strains, but the mutant had a high biomass reduction, after a drug stress. When compared with the reference strain, it was detected a decrease in the susceptibility of the biofilm cells and an increase of β-1,3 glucans in the C. glabrata Δmnn2. The deletion of the MNN2 gene in C. glabrata induces biofilm matrix and cell wall variabilities that increase the resistance to the antifungal drug treatments. The rise of β-1,3 glucans appears to have a role in this effect.

scholarly journals Direct fluorescence imaging of lignocellulosic and suberized cell walls in roots and stems

AoB Plants ◽  
2020 ◽  
Vol 12 (4) ◽  
Author(s):  
Peter Kitin ◽  
Satoshi Nakaba ◽  
Christopher G Hunt ◽  
Sierin Lim ◽  
Ryo Funada
Keyword(s):  
Cell Walls ◽  
Laser Scanning ◽  
Cell Types ◽  
Plant Evolution ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Chemical Information ◽  
Wide Field ◽  
Tissue Preparation ◽  
Plant Structure

Abstract Investigating plant structure is fundamental in botanical science and provides crucial knowledge for the theories of plant evolution, ecophysiology and for the biotechnological practices. Modern plant anatomy often targets the formation, localization and characterization of cellulosic, lignified or suberized cell walls. While classical methods developed in the 1960s are still popular, recent innovations in tissue preparation, fluorescence staining and microscopy equipment offer advantages to the traditional practices for investigation of the complex lignocellulosic walls. Our goal is to enhance the productivity and quality of microscopy work by focusing on quick and cost-effective preparation of thick sections or plant specimen surfaces and efficient use of direct fluorescent stains. We discuss popular histochemical microscopy techniques for visualization of cell walls, such as autofluorescence or staining with calcofluor, Congo red (CR), fluorol yellow (FY) and safranin, and provide detailed descriptions of our own approaches and protocols. Autofluorescence of lignin in combination with CR and FY staining can clearly differentiate between lignified, suberized and unlignified cell walls in root and stem tissues. Glycerol can serve as an effective clearing medium as well as the carrier of FY for staining of suberin and lipids allowing for observation of thick histological preparations. Three-dimensional (3D) imaging of all cell types together with chemical information by wide-field fluorescence or confocal laser scanning microscopy (CLSM) was achieved.

Cytological observation of the infection process of Venturia carpophila on peach leaves

Plant Disease ◽  
2021 ◽  
Author(s):  
Yang Zhou ◽  
Lei Zhang ◽  
Chuan-Ya Ji ◽  
Chingchai Chaisiri ◽  
Liangfen Yin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Laser Scanning ◽  
Infection Process ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Post Inoculation ◽  
Transmission Electron ◽  
Leaf Surfaces ◽  
Germ Tubes

Peach scab caused by Venturia carpophila, is one of the most destructive fungal diseases of peach worldwide, which seriously affects the peach production. Up to date, the infection process and pathogenesis of V. carpophila on peach remain unclear. Here, we present the infection behaviour of V. carpophila at the ultrastructural and cytological levels in peach leaves with combined microscopic investigations (e.g., light microscopy, confocal laser scanning microscopy, scanning electron microscopy and transmission electron microscopy). V. carpophila germinated at the tip of conidia and produced short germ tubes on peach leaf surfaces at 2 days post-inoculation (dpi). At 3 dpi, swollen tips of germ tubes differentiated into appressoria. At 5 dpi, penetration pegs produced by appressoria broke through the cuticle layer, and then differentiated into thick sub-cuticular hyphae in the pectin layer of the epidermal cell walls. At 10 dpi, the sub-cuticular hyphae extensively colonized in the pectin layer. The primary hyphae ramified into secondary hyphae and proliferated along with the incubation. At 15 dpi, the sub-cuticular hyphae divided laterally to form stromata between the cuticle layer and the cellulose layer of the epidermal cells. At 30 dpi, conidiophores developed from the sub-cuticular stromata. Finally, abundant conidiophores and new conidia appeared on leaf surfaces at 40 dpi. These results provide useful information for further understanding the V. carpophila pathogenesis.

scholarly journals Incorporation of In Situ Synthesized Nano-Copper Modified Phenol-Formaldehyde Resin to Improve the Mechanical Properties of Chinese Fir: A Preliminary Study

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 876
Author(s):  
Fan Li ◽  
Cuiyin Ye ◽  
Yanhui Huang ◽  
Xianmiao Liu ◽  
Benhua Fei
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Cell Walls ◽  
Phenol Formaldehyde ◽  
Environmental Scanning Electron Microscopy ◽  
Phenol Formaldehyde Resin ◽  
Chinese Fir ◽  
Formaldehyde Resin ◽  
The Impact

Phenol-formaldehyde (PF) resin, modified using nano-copper with varying contents (0 wt%, 1 wt%, 3 wt%), was manufactured to improve the mechanical properties of Chinese fir. The morphology, chemical, micromechanical and micromechanical properties of the samples were determined by transmission electron microscopy (TEM), atomic force microscopy (AFM), environmental scanning electron microscopy (ESEM), Fourier transform infrared spectroscopy (FTIR), nanoindentation (NI) and traditional mechanical testing. The TEM and AFM results indicated that the in situ synthesized nano-copper particles were well-dispersed, and spherical, with a diameter of about 70 nm in PF resin. From the FTIR chemical changes detected by FTIR inferred that the nano-copper modified PF resin penetrated into the Chinese fir cell walls and interacted with the acetyl groups of hemicellulose by forming a crosslinked structure. Accordingly, the micro-mechanical properties of the Chinese fir cell walls were enhanced after treatment with nano-copper modified PF resin. The filling of the PF-1-Cu resin (1 wt% nano-copper) in the wood resulted in 13.7% and 22.2% increases in the elastic modulus (MOE) and hardness, respectively, of the cell walls. Besides, the impact toughness and compressive strength of the Chinese fir impregnated with PF-1-Cu resin were 21.8% and 8.2% higher than that of the PF-0-Cu resin. Therefore, in situ synthesized nano-copper-modified PF resin is a powerful treatment method for Chinese fir due to improved diffusive properties and reinforcement of the mechanical properties.

scholarly journals Multiscale Modification of Populus cathayana by Alkali Lignin Combined with Heat Treatment

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1240 ◽  
Author(s):  
Haizhen Zhou ◽  
Jingyu Li ◽  
Erni Ma
Keyword(s):  
Heat Treatment ◽  
Sustainable Development ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Wood Fibers ◽  
Alkali Lignin ◽  
Fast Growing ◽  
Populus Cathayana ◽  
Modified Wood

Chemical modification of wood with green modifiers is highly desirable for sustainable development. With the aim of enhancing the water resistance and dimensional stability of fast growing wood, modifications were conducted using renewable and toxicity-free industrial lignin combined with heat treatment. Poplar (Populus cathayana) samples first underwent impregnation with alkali lignin solution and were then subjected to heat treatment at 140–180 °C for two hours. The results indicated that the modified wood showed excellent leaching resistance. The alkali lignin treatment improved surface hydrophobicity and compression strength, and decreased moisture and water uptake, thereby reducing the dimensional instability of modified wood. These changes became more pronounced as the heat-treating temperature increased. Scanning electron microscopy, confocal laser scanning microscopy, and Fourier transform infrared spectroscopy evidenced that a multiscale improvement of the alkali lignin occurred in the cell lumen and cell wall of wood fibers and vessels, with small alkali lignin molecules reacting with the wood matrix. This study paves the way for developing an effective modification approach for fast growing wood, as well as promoting the reuse of industrial lignin for high-value applications, and improves the sustainable development of the forestry industry.

scholarly journals Detecting Bacteria in Wood using a Fluorescent Lipid Probe

1998 ◽  
Vol 6 (7) ◽  
pp. 16-17
Author(s):  
Ying Xiao ◽  
Adya P. Singh ◽  
Robin N. Wakeling
Keyword(s):  
Cell Walls ◽  
Laser Scanning ◽  
Fluorescent Microscopy ◽  
Molecular Probes ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Membrane Probe ◽  
Fungal Hyphae ◽  
Staining Techniques ◽  
Auto Fluorescence

Wood cells have strong autofluorescence in a wide wavelength band due to lignin in the cell walls. The detection of microorganisms in wood is very difficult when using fluorescent microscopy because of interferences. We have recently developed fluorescent staining techniques to differentiate fungal hyphae from wood cell walls (Singh, et al., 1997; Xiao, et al., 1997). This study was aimed at developing fluorescent techniques to visualize bacteria in wood using confocal laser scanning microscopy (CLSM). Nitrobenzoxadiazole glycerophosphoethanolamine (NBD-PE, Molecular Probes), a widely used membrane probe which accords strong fluorescence upon lipids, was compared with glutaraldehyde which had proved useful in our initial attempts to visualize fungal hyphae in wood because of the cell auto fluorescence it causes (Singh et al., 1997).

Micromorphological Characteristics of Compression Wood Degradation in Waterlogged Archaeological Pine Wood

Holzforschung ◽  
1999 ◽  
Vol 53 (4) ◽  
pp. 381-385 ◽  
Author(s):  
Yoon Soo Kim ◽  
Adya P. Singh
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Laser Scanning ◽  
Compression Wood ◽  
Outer Part ◽  
Middle Lamella ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Wood Degradation ◽  
Transmission Electron

Summary The degradation characteristics of waterlogged archaeological compression wood excavated in South Korea were examined by transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). Degradation of Pinus compression wood occurred mainly in the inner part of the S2 layer. In contrast, the outer part of the S2 layer remained relatively intact. CLSM and TEM showed the erosion type of bacterial attack to be dominant in the secondary cell walls of both severe and mild compression wood. However, in some cases the middle lamella was also degraded, which suggests that other forms of microbial attacks, such as bacterial tunnelling, were also present. Bacterial erosion in the severe compression wood was mainly confined to the inner part of the S2 layer whereas in the mild compression wood it also extended into the outer part of the S2 and the S1 layer. The extent of erosion correlated to the differences in the amount and distribution of lignin, particularly in the outer S2 layer between the severe and mild compression wood cells. These features are compared with the degradation of normal Pinus wood.

Sign in / Sign up

Export Citation Format

Share Document