Extractive distribution in Pseudotsuga menziesii: effects on cell wall porosity in sapwood and heartwood

IAWA Journal ◽  
2019 ◽  
Vol 40 (4) ◽  
pp. 721-740 ◽  
Author(s):  
Lloyd A. Donaldson ◽  
Adya Singh ◽  
Laura Raymond ◽  
Stefan Hill ◽  
Uwe Schmitt

ABSTRACT Douglas-fir (Pseudotsuga menziesii) has distinctly colored heartwood as a result of extractive deposition during heartwood formation. This is known to affect natural durability and treatability with preservatives, as well as other types of wood modification involving infiltration with chemicals. The distribution of extractives in sapwood and heartwood of Douglas-fir was studied using fluorescence microscopy. Several different types of extractive including flavonoids, resin acids, and tannins were localized to heartwood cell walls, resin canals, and rays, using autofluorescence or staining of flavonoids with Naturstoff A reagent. Extractives were found to infiltrate the cell walls of heartwood tracheids and were also present to a lesser extent in sapwood tracheid cell walls, especially in regions adjacent to the resin canals. Förster resonance energy transfer measurements showed that the accessibility of lignin lining cell wall micropores to rhodamine dye was reduced by about 50%, probably as a result of cell wall-bound tannin-like materials which accumulate in heartwood relative to sapwood, and are responsible for the orange color of the heartwood. These results indicate that micro-distribution of heartwood extractives affects cell wall porosity which is reduced by the accumulation of heartwood extractives in softwood tracheid cell walls.

2019 ◽  
Vol 218 (4) ◽  
pp. 1408-1421 ◽  
Author(s):  
Xiaohui Liu ◽  
Jiazhou Li ◽  
Heyu Zhao ◽  
Boyang Liu ◽  
Thomas Günther-Pomorski ◽  
...  

Even though cell walls have essential functions for bacteria, fungi, and plants, tools to investigate their dynamic structure in living cells have been missing. Here, it is shown that changes in the intensity of the plasma membrane dye FM4-64 in response to extracellular quenchers depend on the nano-scale porosity of cell walls. The correlation of quenching efficiency and cell wall porosity is supported by tests on various cell types, application of differently sized quenchers, and comparison of results with confocal, electron, and atomic force microscopy images. The quenching assay was used to investigate how changes in cell wall porosity affect the capability for extension growth in the model plant Arabidopsis thaliana. Results suggest that increased porosity is not a precondition but a result of cell extension, thereby providing new insight on the mechanism plant organ growth. Furthermore, it was shown that higher cell wall porosity can facilitate the action of antifungal drugs in Saccharomyces cerevisiae, presumably by facilitating uptake.


2008 ◽  
Vol 38 (6) ◽  
pp. 1536-1546 ◽  
Author(s):  
Nicholas K. Ukrainetz ◽  
Kyu-Young Kang ◽  
Sally N. Aitken ◽  
Michael Stoehr ◽  
Shawn D. Mansfield

Genetic control and relationships among coastal Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii) growth and wood quality traits were assessed by estimating heritability and phenotypic and genetic correlations using 600 trees representing 15 full-sib families sampled from four progeny test sites. Heritability estimates ranged from 0.23 to 0.30 for growth traits, 0.19 for fibre coarseness, from 0.21 to 0.54 for wood density, from 0.16 to 0.97 for cell wall carbohydrates, and 0.79 and 0.91 for lignin content at two sites, Squamish River and Gold River, respectively. Glucose content, indicative of cell wall cellulose composition, and lignin were shown to be under strong genetic control, whereas fibre coarseness was shown to be under weak genetic control. Phenotypic correlations revealed that larger trees generally have longer fibres with higher fibre coarseness, lower density, lower carbohydrate content, a greater proportion of cell wall lignin, and higher microfibril angle. Genetic correlations and correlated response to selection suggest that breeding for height growth would result in a reduction in wood quality, whereas breeding for improved earlywood density in Douglas-fir would result in negligible reductions in volume and appears to be an ideal target for selecting for improved wood quality (density) while maintaining growth in the sample population.


2009 ◽  
Vol 418 (3) ◽  
pp. 615-624 ◽  
Author(s):  
Philip Bardelang ◽  
Mireille Vankemmelbeke ◽  
Ying Zhang ◽  
Hannah Jarvis ◽  
Eleni Antoniadou ◽  
...  

We have developed a polypeptide lysostaphin FRET (fluorescence resonance energy transfer) substrate (MV11F) for the endopeptidase activity of lysostaphin. Site-directed mutants of lysostaphin that abolished the killing activity against Staphylococcus aureus also completely inhibited the endopeptidase activity against the MV11 FRET substrate. Lysostaphin-producing staphylococci are resistant to killing by lysostaphin through incorporation of serine residues at positions 3 and 5 of the pentaglycine cross-bridge in their cell walls. The MV11 FRET substrate was engineered to introduce a serine residue at each of four positions of the pentaglycine target site and it was found that only a serine residue at position 3 completely inhibited cleavage. The introduction of random, natural amino acid substitutions at position 3 of the pentaglycine target site demonstrated that only a glycine residue at this position was compatible with lysostaphin cleavage of the MV11 FRET substrate. A second series of polypeptide substrates (decoys) was developed with the GFP (green fluorescent protein) domain of MV11 replaced with that of the DNase domain of colicin E9. Using a competition FRET assay, the lysostaphin endopeptidase was shown to bind to a decoy peptide containing a GGSGG cleavage site. The MV11 substrate provides a valuable system to facilitate structure/function studies of the endopeptidase activity of lysostaphin and its orthologues.


IAWA Journal ◽  
2014 ◽  
Vol 35 (3) ◽  
pp. 236-252 ◽  
Author(s):  
Jong Sik Kim ◽  
Geoffrey Daniel

The microdistribution of non-cellulosic polysaccharides in epithelial cells of axial resin canals was investigated in Norway spruce xylem using immunolocalization methods combined with monoclonal antibodies specific for (1→4)-β-galactan (LM5), (1→5)-α-arabinan (LM6), homogalacturonan (LM 19, LM20), xyloglucan (LM15), xylan (LM10, LM11) and mannan (LM21, LM22). The ultrastructure and lignin distribution of epithelial cell walls was also examined after cytochemical staining for lignin. Compared with tracheids, epithelial cells showed several different ultrastructural characteristics, such as the thickness of three layers forming the cell wall, the boundary structure between layers and the lamellate structure of cell walls, with slightly stronger reaction with chemical staining for lignin than tracheids. After staining with potassium permanganate, the layer of the epithelial cell wall adjacent to the canal showed typical characteristics of middle lamella (C-ML). However, C-ML regions showed completely different chemical characteristics from E-ML (middle lamella between epithelial cells) regions of epithelial cells and compound middle lamella (CML) regions of tracheids. Unlike tracheids, epitopes of pectic polysaccharides were detected in the epithelial cell wall with variations in amounts between cell wall layers. Epitopes of hemicelluloses were also detected in the epithelial cells with differences in distribution patterns from tracheids, particularly xyloglucan (LM15) and low substituted xylan (LM10) epitopes. Together, our results suggest that the ultrastructure and chemistry of epithelial cells including C-ML regions significantly differ from tracheids.


2020 ◽  
Vol 477 (3) ◽  
pp. 747-762 ◽  
Author(s):  
Ruifang Li ◽  
Zhengwei Liu ◽  
Weibing Dong ◽  
Lan Zhang ◽  
Beibei Zhang ◽  
...  

CGA-N12, an antifungal peptide derived from chromogranin A, has specific antagonistic activity against Candida spp., especially against Candida tropicalis, by inducing cell apoptosis. However, the effect of CGA-N12 on the Candida cell wall is unknown. The Candida protein KRE9, which possesses β-1,6-glucanase activity, was screened by affinity chromatography after binding to CGA-N12. In this study, the effect of CGA-N12 on KRE9 and the interaction between CGA-N12 and KRE9 was studied to clarify the effect of CGA-N12 on C. tropicalis cell wall synthesis. The effect of CGA-N12 on recombinant KRE9 β-1,6-glucanase activity was investigated by analyzing the consumption of glucose. The results showed that CGA-N12 inhibited the activity of KRE9. After C. tropicalis was treated with CGA-N12, the structure of the C. tropicalis cell wall was damaged. The interaction between CGA-N12 and KRE9 was analyzed by isothermal titration calorimetry (ITC). The results showed that their interaction process was involved an endothermic reaction, and the interaction force was mainly hydrophobic with a few electrostatic forces. The results of the fluorescence resonance energy transfer (FRET) assay showed that the distance between CGA-N12 and KRE9 was 7 ∼ 10 nm during their interaction. Therefore, we concluded that the target of CGA-N12 in the C. tropicalis cell membrane is KRE9, and that CGA-N12 weakly binds to KRE9 within a 7 ∼ 10 nm distance and inhibits KRE9 activity.


Author(s):  
S. E. Keckler ◽  
D. M. Dabbs ◽  
N. Yao ◽  
I. A. Aksay

Cellular organic structures such as wood can be used as scaffolds for the synthesis of complex structures of organic/ceramic nanocomposites. The wood cell is a fiber-reinforced resin composite of cellulose fibers in a lignin matrix. A single cell wall, containing several layers of different fiber orientations and lignin content, is separated from its neighboring wall by the middle lamella, a lignin-rich region. In order to achieve total mineralization, deposition on and in the cell wall must be achieved. Geological fossilization of wood occurs as permineralization (filling the void spaces with mineral) and petrifaction (mineralizing the cell wall as the organic component decays) through infiltration of wood with inorganics after growth. Conversely, living plants can incorporate inorganics into their cells and in some cases into the cell walls during growth. In a recent study, we mimicked geological fossilization by infiltrating inorganic precursors into wood cells in order to enhance the properties of wood. In the current work, we use electron microscopy to examine the structure of silica formed in the cell walls after infiltration of tetraethoxysilane (TEOS).


2019 ◽  
Vol 47 (5) ◽  
pp. 1247-1257 ◽  
Author(s):  
Mateusz Dyla ◽  
Sara Basse Hansen ◽  
Poul Nissen ◽  
Magnus Kjaergaard

Abstract P-type ATPases transport ions across biological membranes against concentration gradients and are essential for all cells. They use the energy from ATP hydrolysis to propel large intramolecular movements, which drive vectorial transport of ions. Tight coordination of the motions of the pump is required to couple the two spatially distant processes of ion binding and ATP hydrolysis. Here, we review our current understanding of the structural dynamics of P-type ATPases, focusing primarily on Ca2+ pumps. We integrate different types of information that report on structural dynamics, primarily time-resolved fluorescence experiments including single-molecule Förster resonance energy transfer and molecular dynamics simulations, and interpret them in the framework provided by the numerous crystal structures of sarco/endoplasmic reticulum Ca2+-ATPase. We discuss the challenges in characterizing the dynamics of membrane pumps, and the likely impact of new technologies on the field.


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