Lignin-carbohydrate complex formed in isolated cell walls of callus☆

Whitmore, F. W.

doi:10.1016/s0031-9422(00)89329-2

Cited by 94 publications

(43 citation statements)

References 9 publications

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“…Plants were exposed to ozone in a 50 x 50 x 50-cm vinyl chamber placed in a controlled environment chamber in order to maintain light, temperature, and RH at the same levels as in the growth chamber. Air was drawn through a charcoal filter, supplemented with the desired ozone concentration before entering the exposure chamber, at a rate of 8 (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) leaves/g) were harvested 24 h after ozone exposure always at the middle of the light period to prevent variability in data arising from the possible photoperiodic rhythms. After washing with distilled H20, leaves (1 g) were peeled and epidermes were washed with 100 mM KCI and homogenized in a glass homogenizer with 0.5 ml ice-cold 40 mM MOPS-KOH, 100 mm KC1 (pH 6.5) buffer.…”

Section: Methodsmentioning

confidence: 99%

Peroxidase Release Induced by Ozone in Sedum album Leaves

Castillo¹,

Penel²,

Greppin³

1984

Plant Physiol.

394

168

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ABSTRACrThe effect of ozone was studied on the peroxidase activity from various compartments of Sedam album leaves (epidermis, intercellular fluid, residual cell material, and total cell material). The greatest increase following a 2-hour ozone exposure (OA microliters 03 per liter) was observed in extracellular peroxidases. Most of the main bands of peroxidase activity separated by isoelectric focusing exhibited an increase upon exposure to ozone. Incubation experiments with isolated peeled or unpeeled leaves showed that leaves from ozone-treated plants release much more peroxidases in the medium than untreated leaves. The withdrawal of Ca" ions reduced the level of extracellular peroxidase activity either in whole plants or in incubation experiments. This reduction and the activation obtained after addition of Ca2" resulted from a direct requirement of Ca2" by the enzyme and from an effect of Ca"2 on peroxidase secretion. The ionophore A23187 promoted an increase of extracellular peroxidase activity only in untreated plants. The release of peroxidases by untreated and ozone-treated leaves is considerably lowered by metabolic inhibitors (3-(3,4-dichlorophenyl)-1,1-dimethylurea and sodium azide) and by puromycin.Peroxidase activity increases in plants in response to a great variety ofstresses, including viral, microbial, or fungal infections, salt stress, wounding, or air pollution (9). Several pollutants such as ozone (5,6,22), SO2 (14, 16), or NO2 (13) are known to induce an enhancement ofthe total peroxidase activity of plants. The peroxidase increase following an exposure to ozone is different in different species and is a function of the resistance of the plant to ozone. Ozone-tolerant and ozone-sensitive cultivars have been described, the peroxidase activity of the former being less affected by ozone (5).In a previous work (4), it was shown that there is a parallelism between the level of air pollution and the peroxidase activity measured in Sedum album leaves. This was demonstrated in plants grown in diversely polluted areas. It appeared that S. album is a suitable plant material for the study ofthe mechanism leading plants exposed to a pollutant to increase their peroxidase activity.The present work was performed in the laboratory, under controlled environmental conditions and using standardized amounts of ozone as air pollutant. The dose applied to S. album (0.4 ,ul 1-' for 2 h) is known to increase the total peroxidase activity in many plant species (21,22). Peroxidase activity was measured in several leaf compartments. The data obtained showed that after an exposure to ozone the most significant increase of peroxidase activity occurred in the extracellular compartment. As the release of peroxidase was reported to be a calcium-dependent process in spinach cell suspensions (18), the possible involvement ofthis ion in the control ofthe extracellular peroxidases of S. album leaves was also investigated in relation with the response to ozone. MATERIALS AND METHODSPlant Material and Growing Conditions. Sedu...

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Section: Methodsmentioning

confidence: 99%

Peroxidase Release Induced by Ozone in Sedum album Leaves

Castillo¹,

Penel²,

Greppin³

1984

Plant Physiol.

394

168

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“…DHPs (formed using 14 C-labeled coniferyl alcohol, H 2 O 2 and peroxidase) strongly bound to BSA, gelatin and synthetic polyhydroxy proline polymer [99]. Pinus elliotti cell wall preparations incubated with H 2 O 2 and coniferyl alcohol also resulted in the formation of lignin that bound to a hydroxyproline-containing protein, speculated to be extensin [100]. Whitmore extended this work by showing that cell walls washed with detergent and 2M NaCl, increased its lignin weight fraction following incubation with coniferyl alcohol and H 2 O 2 , suggesting that cell-wall bound peroxidase was catalyzing the reaction.…”

Section: Lignin-protein Interactions?mentioning

confidence: 99%

Supramolecular Self-Assembled Chaos: Polyphenolic Lignin’s Barrier to Cost-Effective Lignocellulosic Biofuels

et al. 2010

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Phenylpropanoid metabolism yields a mixture of monolignols that undergo chaotic, non-enzymatic reactions such as free radical polymerization and spontaneous selfassembly in order to form the polyphenolic lignin which is a barrier to cost-effective lignocellulosic biofuels. Post-synthesis lignin integration into the plant cell wall is unclear, including how the hydrophobic lignin incorporates into the wall in an initially hydrophilic milieu. Self-assembly, self-organization and aggregation give rise to a complex, 3D network of lignin that displays randomly branched topology and fractal properties. Attempts at isolating lignin, analogous to archaeology, are instantly destructive and nonrepresentative of in planta. Lack of plant ligninases or enzymes that hydrolyze specific bonds in lignin-carbohydrate complexes (LCCs) also frustrate a better grasp of lignin. Supramolecular self-assembly, nano-mechanical properties of lignin-lignin, ligninpolysaccharide interactions and association-dissociation kinetics affect biomass deconstruction and thereby cost-effective biofuels production. OPEN ACCESSMolecules 2010, 15 8642

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“…Phenolic polymer deposition was quantified by modifications of established protocols for the thioglycolic acid assay (21,38). This procedure is the method of choice for the measurement of herbaceous phenolic polymers, since it involves minimal chemical alterations of individual phenolic residues and results in a thioglycolic acid derivative which is readily purified away from potential contaminants, including esterified phenolic monomers and noncovalently linked proteins (29,34 Purified phenolic polymer-thioglycolic acid derivatives were prepared from elicitor-treated cotyledon tissues for initial characterization and to obtain a standard curve for quantitation of the analytical samples.…”

Section: Hplc Of Soluble Aromatics and Phenolic Polymer Measurementmentioning

confidence: 99%

Rapid Accumulation of Anionic Peroxidases and Phenolic Polymers in Soybean Cotyledon Tissues following Treatment with Phytophthora megasperma f. sp. Glycinea Wall Glucan

Graham¹,

Graham²

1991

Plant Physiol.

159

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Phytophthora megasperma Drechs. f. sp. glycinea Kuan & Erwin (PMG) cell wall glucan has been extensively characterized as an elicitor of the pterocarpan phytoalexins, the glyceollins in soybean (Glycine max L.). Just recently, this glucan was shown to be a potent elicitor of conjugates of the isoflavones, daidzein and genistein as well. Here we report that PMG wall glucan also induces a rapid and massive accumulation of phenolic polymers in soybean cotyledon cells proximal to the point of elicitor application. Deposition of phenolic polymers is over ten times that in wounded controls within just 4 hours of elicitor treatment and reaches a maximum by 24 hours. In the same tissues, isoflavone conjugates begin to accumulate at 8 hours and glyceollin at 12 hours. By 24 hours, the total deposition of wall bound phenolics in elicitor-treated tissues is several times greater than the peak glyceollin and isoflavone responses combined. Histochemical stains and quantitation of phenolic residues released after saponification and nitrobenzene or copper oxide oxidation suggest that the covalently linked phenolics include both lignin-and suberin-like polymers as well as simple esterified coumaric and ferulic acid monomers. Accumulations of phenolic polymers are accompanied by equally rapid and massive increases in activity of a specific group of anionic peroxidases. Although increases in peroxidase activity are not strictly limited to cells immediately adjacent to the area of elicitor treatment, the deposition of phenolic polymers is significantly less extensive in distal cells.The soybean-PMG2 association provides an excellent system to study molecular aspects of host-pathogen interactions. the glyceollins, which are synthesized from phenylalanine through well characterized enzymatic pathways (8). The accumulation of the glyceollins generally correlates very well with race-specific resistance as conditioned by the Rps genes (7,8,25).In the laboratory, race-specific resistance to PMG is observed in all soybean seedling organs (e.g. 2,3,18,20,31,40). Of these various organs, however, cotyledons are particularly suited for investigations of the spatial and temporal coordination of molecular defense responses (17). This is due to their distinctively simple cellular architecture; other than the epidermis and a few major vascular elements, they consist mainly of tightly aligned columns of highly uniform mesophyll parenchmya cells. To ensure that studies with cotyledons are physiologically meaningful, we have confirmed and extended earlier reports (31) of race specific infection in this organ. We demonstrated that all aspects of the response of the organ to infection by PMG, including disease progression, symptoms, and the timing, magnitude and spatial accumulations of glyceollin, resemble the race-specific responses of other organs ( 18).Employing a sensitive HPLC profiling procedure (14) to study soluble phenylpropanoid-derived metabolites, we have disclosed the presence oflarge constitutive pools ofconjugates of two clo...

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Lignin-carbohydrate complex formed in isolated cell walls of callus☆

Cited by 94 publications

References 9 publications

Peroxidase Release Induced by Ozone in Sedum album Leaves

Peroxidase Release Induced by Ozone in Sedum album Leaves

Supramolecular Self-Assembled Chaos: Polyphenolic Lignin’s Barrier to Cost-Effective Lignocellulosic Biofuels

Rapid Accumulation of Anionic Peroxidases and Phenolic Polymers in Soybean Cotyledon Tissues following Treatment with Phytophthora megasperma f. sp. Glycinea Wall Glucan

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