Etude ultrastructurale des processus de biodégradation. I. Pourriture blanche des feuilles de Hêtre (Fagus sylvatica L.)

1978 ◽  
Vol 24 (6) ◽  
pp. 725-733 ◽  
Author(s):  
O. Reisinger ◽  
F. Toutain ◽  
F. Mangenot ◽  
Marie-France Arnould
Keyword(s):  
Cell Walls ◽  
Developmental Stages ◽  
Lethal Factor ◽  
White Rot ◽  
Apical Region ◽  
Vascular Bundles ◽  
Plant Cell Walls ◽  
Electron Microscopic ◽  
Fagus Sylvatica L

An electron microscopic study of beech leaf white rot shows a certain number of characteristic developmental stages which are identical whether the material is from in vitro experimentation or from natural incubation. Endowed with a cellulolytic property seemingly localized in the apical region only, hyphae of the white rot agent only traverse the plant cell walls. Subsequently, hyphae penetrate condensed protoplasmic residues and make them progressively transparent to electrons. During this discoloring process, a lethal factor of as yet unknown nature appears, affecting other microorganisms already present in the leaves. Phloem and xylem vascular bundles do not present notable ultrastructural modifications. Therefore, leaf discoloration is not due to an alteration of the xylem constituents but to changes having occurred in the condensed cytoplasmic residues of the dead tissues.

Wheat cell walls and constituent polysaccharides induce similar microbiota profiles upon in vitro fermentation despite different short chain fatty acid end-product levels.

2021 ◽  
Author(s):  
Shiyi Lu ◽  
Deirdre Mikkelsen ◽  
Hong Yao ◽  
Barbara Williams ◽  
Bernadine Flanagan ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Gut Microbiota ◽  
Plant Cell ◽  
Cell Walls ◽  
Short Chain Fatty Acid ◽  
Chain Fatty Acid ◽  
Plant Cell Walls ◽  
Human Gut ◽  
In Vitro Fermentation

Plant cell walls as well as their component polysaccharides in foods can be utilized to alter and maintain a beneficial human gut microbiota, but it is not known whether the...

Electron microscopic observations of infection threads in driselase treated nodules of Astragalus sinicus

1986 ◽  
Vol 32 (12) ◽  
pp. 947-952 ◽  
Author(s):  
Shiro Higashi ◽  
Kazuya Kushiyama ◽  
Mikiko Abe
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Root Nodules ◽  
Morphological Characteristics ◽  
Enzyme Treatment ◽  
Vascular Bundles ◽  
Electron Microscopic ◽  
Astragalus Sinicus ◽  
Infection Threads

The morphological characteristics of infection threads in the root nodules of Astragalus sinicus were examined by scanning and transmission electron microscopy. The infection threads, epidermal cell walls, and vascular bundles of the nodule were not altered when a nodule was treated with driselase (a plant cell wall degrading enzyme), although the cell walls of meristematic and bacteroid-including zones were completely decomposed by the enzyme treatment. Some infection threads were funnel shaped at the site of attachment of the infection thread to the host cell wall.

scholarly journals In Vitro Autolysis of Plant Cell Walls

1967 ◽  
Vol 42 (7) ◽  
pp. 968-972 ◽  
Author(s):  
Su-Hwa Lee ◽  
A. Kivilaan ◽  
Robert S. Bandurski
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Plant Cell Walls

Purified plant cell walls with adsorbed polyphenols alter porcine faecal bacterial communities during in vitro fermentation

2020 ◽  
Vol 11 (1) ◽  
pp. 834-845 ◽  
Author(s):  
Lucas J. Grant ◽  
Deirdre Mikkelsen ◽  
Anh Dao T. Phan ◽  
Seungha Kang ◽  
Diane Ouwerkerk ◽  
...  
Keyword(s):  
Plant Cell ◽  
Bacterial Communities ◽  
Dietary Fibre ◽  
Cell Walls ◽  
Plant Cell Walls ◽  
In Vitro Fermentation ◽  
Bacterial Populations

A simplified in vitro model to indicate microbiota changes to polyphenols associated with dietary fibre in whole fruits, noting differences in bacterial populations between polyphenolic groups during fermentation.

Fingerprinting of polysaccharides attacked by hydroxyl radicals in vitro and in the cell walls of ripening pear fruit

2001 ◽  
Vol 357 (3) ◽  
pp. 729-737 ◽  
Author(s):  
Stephen C. FRY ◽  
Jo C. DUMVILLE ◽  
Janice G. MILLER
Keyword(s):  
Hydroxyl Radicals ◽  
Cell Walls ◽  
Plant Cell Walls ◽  
Pear Fruit ◽  
Connective Tissues ◽  
Softening Process ◽  
Radical Attack

Hydroxyl radicals (•OH) may cause non-enzymic scission of polysaccharides in vivo, e.g. in plant cell walls and mammalian connective tissues. To provide a method for detecting the action of endogenous •OH in vivo, we investigated the products formed when polysaccharides were treated with •OH (generated in situ by ascorbate-H2O2-Cu2+ mixtures) followed by NaB3H4. Treatment with •OH increased the number of NaB3H4-reacting groups present in citrus pectin, homogalacturonan and tamarind xyloglucan. This increase is attributed partly to the formation of glycosulose and glycosulosuronic acid residues, which are then reduced back to the original (but radioactive) sugar residues and their epimers by NaB3H4. The glycosulose and glycosulosuronic acid residues were stable for > 16h at 20°C in ethanol or buffer (pH4.7), but were destroyed in alkali. Driselase-digestion of the radiolabelled polysaccharides yielded characteristic patterns of 3H-products, which included galactose and galacturonate from pectin, and isoprimeverose, galactose, glucose and arabinose from xyloglucan. Pectin yielded at least eight 3H-labelled anionic products, separable by electrophoresis at pH3.5. The patterns of radioactive products form useful ‘fingerprints’ by which •OH-attacked polysaccharides may be recognized. Applied to the cell walls of ripening pear (Pyrus communis) fruit, the method gave evidence for progressive •OH radical attack on polysaccharides during the softening process.

Some histochemical features of anther wall of Leucojum aestivum (Amaryllidaceae) during pollen development

Biologia ◽  
2012 ◽  
Vol 67 (5) ◽  
Author(s):  
Nuran Ekici ◽  
Feruzan Dane
Keyword(s):  
Cell Walls ◽  
Cell Activation ◽  
Developmental Stages ◽  
Middle Layer ◽  
Point Of View ◽  
Anther Wall ◽  
Vascular Bundles ◽  
Thin Sections ◽  
Leucojum Aestivum ◽  
Rna Content

AbstractIn this study, polysaccharide and RNA contents of anthers were investigated on different phases of sporogenesis by using light microscopy techniques from histological and cytological point of view in Leucojum aestivum. Paraffin and semi-thin sections of anthers were stained with toluidine blue and PAS. Anthers were tetrasporangiate. The wall of the anther consists of an epidermis, endothecium, middle layer and glandular tapetum. During one nucleated microspore and mature pollen phase microspores and tapetum cells began to degenerate and they were become very rich of RNA in L. aestivum. And also RNA content was increased in endothecium and middle layer cells except the epidermis cells of anther wall. An increase in RNA content indicates cell activation. Polysaccharides were not seen in young anther wall but they were seen in older ones. They were generally condensed in the cell walls and especially in the cell walls of vascular bundles of connective tissue. This could be thought that insoluble polysaccharides were used in metabolic events in early developmental stages. Appearance of polysaccharides in late phases was indicated that polysaccharides were used in the formation of cuticule and differentiation of endothelium cell walls.

EM and microspectrophotometric analysis of biological delignification of plants

1995 ◽  
Vol 53 ◽  
pp. 986-987
Author(s):  
D. E. Akin ◽  
L. L. Rigsby ◽  
W. H. Morrison ◽  
A. Sethuraman ◽  
K.-E. L. Eriksson
Keyword(s):  
Gas Chromatography ◽  
Plant Cell ◽  
Cell Walls ◽  
Plant Biomass ◽  
White Rot Fungi ◽  
Uv Absorption ◽  
White Rot ◽  
Plant Cell Walls ◽  
Rumen Microorganisms ◽  
Cyathus Stercoreus

Aromatic constituents such as lignin bind to carbohydrates within plant cell walls and thus render the plant carbohydrates less utilizable as food and energy. Chemical methods used to upgrade the quality of plant biomass are costly, expensive, and unsafe. White rot fungi, which are the only known microorganisms that, to any extent, can remove lignin from plant cell walls, offer a biological solution to upgrading plant quality. Microscopic analyses provide information on the site of delignification that is strategically important in improving use of plant biomass.Stems of grasses and a legume were treated with the white rot fungi Ceriporiopsis subvermispora and Cyathus stercoreus for 6 weeks. Treated residues were analyzed for structural modifications using scanning and transmission electron microscopy and for aromatic constituents using ultraviolet (UV) absorption microspectrophotometry and gas chromatography. These modifications were related to improved utilization of cell walls by rumen microorganisms.UV absorption microspectrophotometry, in conjunction with gas-chromatography of alkali-treated plants, indicated that ester-linked ferulic and ρ-coumaric acids were particularly susceptible to removal by both fungal species.

UV absorption microspectroscopy and alkali extraction to characterize aromatic constituents in plant cell walls

1993 ◽  
Vol 51 ◽  
pp. 138-139
Author(s):  
D. E. Akin ◽  
W. H. Morrison ◽  
L. L. Rigsby
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Plant Biomass ◽  
Pennisetum Glaucum ◽  
Cell Types ◽  
Vascular Bundles ◽  
Plant Cell Walls ◽  
Microbial Utilization ◽  
Carbon Recycling ◽  
Treated Plant

Aromatic compounds bound to structural carbohydrates in plant cell walls limit the microbial utilization of otherwise biodegradable polysaccharides. Such limitations have important consequences in conversion of plant biomass to useful products and in carbon recycling. These aromatic constituents are chemically diverse, with further variations occurring in chemical linkages. Microspectroscopy and chemical analysis of alkali-treated plant walls was used to investigate aromatics.Pearl millet (Pennisetum glaucum) stems (Fig. 1) were separated into pith parenchyma, pith vascular bundles, and rind (vascular and sclerenchyma cells combined). A normal (N) line and a counterpart brown midrib (bmr) mutant line, which has modified lignins, were both sampled. Ground (~ 1 mm) walls of these cell types were sequentially treated with 1M NaOH at 25°C for 20 h to remove ester-linked phenolic acids, and the residues were then treated with 4M NaOH in Teflon polyfluoroalkoxy copolymer vials which were placed in stainless steel vessels at 170°C for 2 h to remove more resistant ether-linked and polymerized aromatics.

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