Microstructure and Quantitative Micromechanical Analysis of Wood Cell–Emulsion Polymer Isocyanate and Urea–Formaldehyde Interphases

2017 ◽  
Vol 23 (3) ◽  
pp. 687-695 ◽  
Author(s):  
Lizhe Qin ◽  
Lanying Lin ◽  
Feng Fu ◽  
Mizi Fan
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Laser Scanning ◽  
Urea Formaldehyde ◽  
Wood Adhesive ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Micromechanical Analysis ◽  
Emulsion Polymer ◽  
Uf Resin

AbstractEmulsion polymer isocyanate (EPI) and urea-formaldehyde (UF) were selected as typical resin systems to investigate the microstructure of wood–adhesive interphases by fluorescence microscopy (FM) and confocal laser scanning microscopy (CLSM). Further, a quantitative micromechanical analysis of the interphases was conducted using nanoindentation. The FM results showed that the UF resin could penetrate the wood to a greater extent than the EPI resin, and that the average penetration depth for these two resin systems was higher in the case of latewood. CLSM allowed visualization of the resin distribution with contrasting colors, showing that the EPI resin could not penetrate the cell wall, whereas UF resin could enter the cell walls. The micromechanical properties of the cell walls were almost unaffected by EPI penetration but were significantly affected by UF penetration, especially in the first cell wall from the glueline. This further confirmed that only cell walls with resin penetration can improve the mechanical properties of the interphase regions.

scholarly journals The Expandables: Cracking the Staphylococcal Cell Wall for Expansion Microscopy

2021 ◽  
Vol 11 ◽  
Author(s):  
Tobias C. Kunz ◽  
Marcel Rühling ◽  
Adriana Moldovan ◽  
Kerstin Paprotka ◽  
Vera Kozjak-Pavlovic ◽  
...  
Keyword(s):  
Cell Wall ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Intracellular Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Planktonic Bacteria ◽  
Simkania Negevensis

Expansion Microscopy (ExM) is a novel tool improving the resolution of fluorescence microscopy by linking the sample into a hydrogel that gets physically expanded in water. Previously, we have used ExM to visualize the intracellular Gram-negative pathogens Chlamydia trachomatis, Simkania negevensis, and Neisseria gonorrhoeae. Gram-positive bacteria have a rigid and thick cell wall that impedes classic expansion strategies. Here we developed an approach, which included a series of enzymatic treatments resulting in isotropic 4× expansion of the Gram-positive pathogen Staphylococcus aureus. We further demonstrate the suitability of the technique for imaging of planktonic bacteria as well as endocytosed, intracellular bacteria at a spatial resolution of approximately 60 nm with conventional confocal laser scanning microscopy.

scholarly journals Morphological aspects of self-repair of lesions caused by internal growth stresses in stems of Aristolochia macrophylla and Aristolochia ringens

2010 ◽  
Vol 277 (1691) ◽  
pp. 2113-2120 ◽  
Author(s):  
Sebastian Busch ◽  
Robin Seidel ◽  
Olga Speck ◽  
Thomas Speck
Keyword(s):  
Cell Wall ◽  
Laser Scanning ◽  
Early Stage ◽  
Morphological Changes ◽  
Secondary Growth ◽  
Laser Scanning Microscopy ◽  
Morphological Data ◽  
Confocal Laser ◽  
Growth Stresses ◽  
Self Repair

This study reveals in detail the mechanism of self-repair during secondary growth in the vines Aristolochia macrophylla and Aristolochia ringens based on morphological data. For a comprehensive understanding of the underlying mechanisms during the self-repair of lesions in the sclerenchymatous cylinder of the stem, which are caused by internal growth stresses, a classification of morphological changes in the cells involved in the repair process is required. In an early stage of self-repair, we observed morphological changes as a mere extension of the turgescent cortex cells surrounding the lesion, whereby the cell wall extends locally through visco-elastic/plastic deformation without observable cell wall synthesis. Later stages involve typical cell growth and cell division. Several successive phases of self-repair were investigated by light microscopy of stained samples and confocal laser-scanning microscopy in fluorescence mode. The results indicate that A. macrophylla and A. ringens respond to lesions caused by internal growth stresses with a sophisticated self-repair mechanism comprising several phases of different repair modes.

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 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 Proteomic Analysis of Caspofungin-Induced Responses in Planktonic Cells and Biofilms of Candida albicans

2021 ◽  
Vol 12 ◽  
Author(s):  
Peng Li ◽  
Chaminda J. Seneviratne ◽  
Qingxian Luan ◽  
Lijian Jin
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Stress Response ◽  
Laser Scanning ◽  
Metabolic Regulation ◽  
Antifungal Resistance ◽  
Laser Scanning Microscopy ◽  
Cell Wall Integrity ◽  
Confocal Laser ◽  
Planktonic Cells

Candida albicans biofilms display markedly increased antifungal resistance, and the underlying mechanisms remain unclear. This study investigated the signature profiles of C. albicans planktonic cells and biofilms in response to caspofungin (CAS) by mass spectrometry-based shotgun proteomics. We found that C. albicans biofilms were twofold more resistant to CAS with reference to planktonic cells. Notably, 9.6% of C. albicans biofilm cells survived the lethal treatment of CAS (128 μg/ml), confirmed by LIVE/DEAD staining, confocal laser scanning microscopy (CLSM) and scanning electron microscopy analyses. The responses of C. albicans planktonic cells and biofilms to CAS treatment at respective minimum inhibitory concentrations (MICs) were assessed by high-throughput proteomics and bioinformatics approaches. There were 148 and 224 proteins with >twofold difference identified from the planktonic cells and biofilms, respectively. CAS treatment downregulated several cell wall- and oxidative stress-related proteins. Whereas, CAS-induced action was compensated by markedly increased expression of many other proteins involved in cell wall integrity and stress response (e.g., heat shock proteins). Moreover, considerable expression changes were identified in metabolism-associated proteins like glycolysis, tricarboxylic acid (TCA) cycle and ATP biosynthesis. Importantly, various key proteins for cell wall integrity, stress response and metabolic regulation (e.g., PIL1, LSP1, HSP90, ICL1, and MLS1) were exclusively enriched and implicated in C. albicans biofilms. This study demonstrates that C. albicans biofilms undergo highly complicated yet complex regulation of multiple cellular pathways in response to CAS. Signature proteins essential for modulating cell wall integrity, stress response and metabolic activities may account for the antifungal resistance of C. albicans biofilms.

Fabrication of highly stable and durable furfurylated wood materials. Part II: the multi-scale distribution of furfuryl alcohol (FA) resin in wood

Holzforschung ◽  
2020 ◽  
Vol 74 (12) ◽  
pp. 1147-1155
Author(s):  
Wanju Li ◽  
Minghui Liu ◽  
Hankun Wang ◽  
Yan Yu
Keyword(s):  
Cell Wall ◽  
Furfuryl Alcohol ◽  
Laser Scanning ◽  
Chinese Fir ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Microscopy Imaging ◽  
Multi Scale ◽  
Ray Cells ◽  
Ft Ir

AbstractThe aim of this investigation was mainly to evaluate the multi-scale distribution of furfuryl alcohol (FA) resin in modified Chinese fir and poplar wood. 13C CP/MAS NMR, Scanning Electron Microscopy (SEM), Confocal Laser Scanning Microscopy (CLSM), Nanoindentation and Imaging Fourier transform infrared microscopy (Imaging FT-IR) were applied to describe the FA resin distribution in wood from bulk to cell wall scale. The results showed that FA resin were mainly located in the cell cavity of Chinese fir tracheids. For poplar, FA resin was mostly deposited in the cavity of fibers and ray cells, while little was found in the adjacent vessels. Lots of pits of wood cells were covered with FA resin which implied a higher risk of drying after wood furfurlation in practical production. Nanoindentation demonstrated that FA resin could easily infiltrate into the wood cell wall because both reduced modulus and hardness of the modified wood cell walls were significantly improved. This conclusion was further supported by the results of imaging FT-IR.

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