scholarly journals Location of uronic acid group in Japanese cedar and Japanese beech wood cell walls as evaluated by the influences of minerals on thermal reactivity

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Jiawei Wang ◽  
Eiji Minami ◽  
Haruo Kawamoto
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Uronic Acid ◽  
Free Acid ◽  
Beech Wood ◽  
Acid Catalyst ◽  
Japanese Cedar ◽  
Acid Group ◽  
Base Catalyst ◽  
Japanese Beech

AbstractThe thermal reactivities of cellulose and hemicellulose are significantly different in cell walls when compared with isolated components and differ in Japanese cedar (softwood) and Japanese beech (hardwood). Uronic acid bound to xylan promotes the thermal degradation of cellulose and hemicellulose, and its effect is different depending on the form of free acid (acting as an acid catalyst) or metal uronate (acting as a base catalyst). We evaluated the location of uronic acid in the cell wall by identifying the components affected by demineralization in pyrolysis of cedar and beech wood. The thermal reactivities of xylan and glucomannan in beech were changed by demineralization, but in cedar, glucomannan and cellulose reactivities were changed. Therefore, the location of uronic acid in the cell wall was established and differed between cedar and beech; close to glucomannan and xylan in beech, but close to glucomannan and cellulose in cedar. Such information is important for understanding the ultrastructure and pyrolysis behavior of softwood and hardwood cell walls.

scholarly journals Thermal degradation of hemicellulose and cellulose in ball-milled cedar and beech wood

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Jiawei Wang ◽  
Eiji Minami ◽  
Mohd Asmadi ◽  
Haruo Kawamoto
Keyword(s):  
Thermal Degradation ◽  
Ball Milling ◽  
Cell Walls ◽  
Uronic Acid ◽  
Beech Wood ◽  
Cellulose Microfibrils ◽  
Homogeneous Distribution ◽  
Japanese Beech ◽  
Temperature Range ◽  
The Matrix

AbstractThe thermal degradation reactivities of hemicellulose and cellulose in wood cell walls are significantly different from the thermal degradation behavior of the respective isolated components. Furthermore, the degradation of Japanese cedar (Cryptomeria japonica, a softwood) is distinct from that of Japanese beech (Fagus crenata, a hardwood). Lignin and uronic acid are believed to play crucial roles in governing this behavior. In this study, the effects of ball milling for various durations of time on the degradation reactivities of cedar and beech woods were evaluated based on the recovery rates of hydrolyzable sugars from pyrolyzed wood samples. The applied ball-milling treatment cleaved the lignin β-ether bonds and reduced the crystallinity of cellulose, as determined by X-ray diffraction. Both xylan and glucomannan degraded in a similar temperature range, although the isolated components exhibited different reactivities because of the catalytic effect of uronic acid bound to the xylose chains. These observations can be explained by the more homogeneous distribution of uronic acid in the matrix of cell walls as a result of ball milling. As observed for holocelluloses, cellulose in the ball-milled woods degraded in two temperature ranges (below 320 °C and above); a significant amount of cellulose degraded in the lower temperature range, which significantly changed the shapes of the thermogravimetric curves. This report compares the results obtained for cedar and beech woods, and discusses them in terms of the thermal degradation of the matrix and cellulose microfibrils in wood cell walls and role of lignin. Such information is crucial for understanding the pyrolysis and heat treatment of wood.

scholarly journals 269 CELL WALL CHANGES IN RIPENING NASH1 (HOSUI) FRUIT

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 468d-468
Author(s):  
L.D. Melton ◽  
L.M. Davies
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Uronic Acid ◽  
Major Effect ◽  
Water Soluble ◽  
Tris Buffer ◽  
Side Chains ◽  
Neutral Sugar ◽  
Fruit Texture ◽  
Alditol Acetates

Cell wall changes during ripening have a major effect on fruit texture. The cell walls isolated using phenol-Tris buffer were sequentially extracted to give polysaccharide fractions that contained mainly water-soluble pectin, chelator-soluble (CDTA) pectin, hemicelluloses (0.05 M Na2CO3 followed by 1M and 4M KOH) and cellulose. The fractions were analyzed colorimetrically for uronic acid, total neutral sugar and cellulose contents. The component sugars of each fraction were determined as their alditol acetates by GC. Then was a decrease in the two pectin fractions during ripening. The pectins appear to have arabinan and galactan side chains. Pectic galactose decreases during ripening. The weight of the combined hemicellulose fractions did not change during ripening, nor did the cellulose level. At least two types of arabinan are present. Pectins were found in all cell wall fractions. Nashi cell walls contain a relatively large amount of xylan compared to other fruit.

scholarly journals 270 EFFECTS OF INTERMITTENT WARMING ON CELL WALLS OF NECTARINES

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 468e-468
Author(s):  
D.M. Dawson ◽  
L.D. Melton ◽  
D.M. Dawson ◽  
C.B. Watkins
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Uronic Acid ◽  
Prunus Persica ◽  
Side Chains ◽  
Cool Storage ◽  
Intermittent Warming ◽  
Storage Temperatures ◽  
Polygalacturonase Activity

Nectarine fruit (Prunus persica (L) Batsch) cv. Fantasia, were ripened immediately after harvest (normal ripening), or stored for 6 weeks either continuously at 0°C or were intermittently warmed (IW) for 48 h at 20C after 2 and 4 weeks, and then ripened. Fruit subjected to IW ripened normally, whereas the continuously stored fruit developed mealiness during ripening. Normal ripening was associated with solubilization and depolymerization of pectic polymers and a net loss of galactose. Only limited pectic solubilization and removal of side chains occurred during ripening of mealy fruit. Pectic polymer polymerization occurred at each IW occasion continued during ripening after storage, but was not as extensive as in normally ripened fruit. Mealy fruit had high autolytic capacity, probably as a result of insoluble pectic polymers in the cell wall that were not solubilized during ripening. The release of uronic acid suggests that cool storage temperatures do not irreversibly inhibit polygalacturonase activity.

Raman microscopic analysis of wood after treatment with the ionic liquid, 1-ethyl-3-methylimidazolium chloride

Holzforschung ◽  
2015 ◽  
Vol 69 (3) ◽  
pp. 273-279 ◽  
Author(s):  
Toru Kanbayashi ◽  
Hisashi Miyafuji
Keyword(s):  
Molecular Structure ◽  
Cell Wall ◽  
Ionic Liquid ◽  
Raman Spectra ◽  
Cell Walls ◽  
Cryptomeria Japonica ◽  
Microscopic Analysis ◽  
Japanese Cedar ◽  
Wall Structure ◽  
Chemical Components

Abstract Japanese cedar (Cryptomeria japonica) was treated with the ionic liquid (IL) 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]), which is a solvent for cellulose, and the changes in the chemical components and their distribution in wood cell walls have been investigated by Raman microscopy. Raman spectra, recorded from various areas of the cell walls, showed that lignin in the compound middle lamellae (CML) and cell corners (CC) was resistant to the reaction with [C2mim][Cl], but its molecular structure changed partially. The reactivity of cellulose and hemicelluloses with [C2mim][Cl] was higher than that of lignin in the cell wall, and the cell wall structure was maintained even in an advanced state of the reactions. The effects of [C2mim]-[Cl] on cellulose and hemicelluloses in the cell wall were homogeneous, whereas that of lignin was inhomogeneous.

scholarly journals Effect of delignification on thermal degradation reactivities of hemicellulose and cellulose in wood cell walls

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Jiawei Wang ◽  
Eiji Minami ◽  
Mohd Asmadi ◽  
Haruo Kawamoto
Keyword(s):  
Thermal Degradation ◽  
Cell Walls ◽  
Japanese Cedar ◽  
Fagus Crenata ◽  
Cellulose Microfibrils ◽  
Japanese Beech ◽  
Base Catalysts ◽  
Research Fields ◽  
Acid And Base ◽  
The Matrix

AbstractThe thermal degradation reactivities of cellulose and hemicellulose are substantially different in Japanese cedar (Cryptomeria japonica, a softwood) and Japanese beech (Fagus crenata, a hardwood). Uronic acid and its salts act as acid and base catalysts, respectively, and their specific placement in the cell walls has been considered a factor that influences degradation reactivity. In this study, the role of lignin in degradation reactivity was investigated using holocellulose prepared from cedar and beech woods. The thermal degradation reactivities of cellulose and hemicellulose in holocellulose were evaluated according to the recovery of hydrolyzable sugars from heat-treated samples and compared with those of wood samples. Results show that the reactivities of xylan and glucomannan in both woods became similar to those of the corresponding isolated samples when lignin was removed. By contrast, the cellulose in both woods became more reactive when lignin was removed, and the degradation could be separated into two modes depending on the reactivity. These results were analyzed in terms of the effect of lignin on the matrix of cell walls and the interaction between the matrix and surface molecules of cellulose microfibrils. Differential thermogravimetric curves of the holocellulose samples were obtained and explained in terms of the degradation of hemicellulose and cellulose. The reported findings will provide insights into the research fields of wood pyrolysis and cell wall ultrastructures.

Silicification of wood-cell walls

1994 ◽  
Vol 52 ◽  
pp. 428-429
Author(s):  
S. E. Keckler ◽  
D. M. Dabbs ◽  
N. Yao ◽  
I. A. Aksay
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Cell Walls ◽  
Lignin Content ◽  
Resin Composite ◽  
Middle Lamella ◽  
Cellulose Fibers ◽  
Complex Structures ◽  
Rich Region ◽  
Inorganic Precursors

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).

Histological aspects of the cryopreservation of potato

2008 ◽  
Vol 56 (3) ◽  
pp. 341-348
Author(s):  
P. Pepó ◽  
A. Kovács
Keyword(s):  
Cell Wall ◽  
Low Temperatures ◽  
Cell Walls ◽  
Cellular Level ◽  
Adaptive Mechanism ◽  
Epidermal Layer ◽  
Freezing And Thawing ◽  
Meristematic Cells ◽  
Suitable Solution ◽  
Vacuolated Cells

Cryopreservation appears to be a suitable solution for the maintenance of potato germplasms. The protocol described in this paper can be applied for the vitrification and preservation of meristems. During histo-cytological studies it is possible to observe modifications at the cellular level and to understand the adaptive mechanism to low temperatures. Control potato meristem tissue contained a number of meristematic cells with a gradient of differentiation. After freezing there were a large number of vacuolated cells, some of which exhibited broken cell walls and plasmolysis. The thickening of the cell wall, giving them a sinuous appearance, was observed after freezing and thawing the meristems, with ruptures of the cuticle and epidermal layer.

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