Plants cell wall structure

Fusinite maceral distinguished by the well-preserved original form of plant cell wall structure, intact or broken, with open or mineral-filled cell lumens (cavities). 

Semifusinite maceral that is intermediate in reflectance between fusinite and associated vitrinite that shows plant cell wall structure with cavities generally oval or elongated in cross section, but in some specimens less well defined than in fusinite often, occurs as a transitional material between vitrinite and fusinite. 

Limonene. Use of fungal cultures which produce hydrolytic enzymes were used to increase the yield of endogenous products in citrus. Enzymatic digestion of plant cell wall structures or other sub-cellular structures enhances solubilization of these by-products. 

Figure 1 Schematic and hypothetical model for primary plant cell wall structure (adapted from ref. 5)...

Combination of hemicelluloses with nanosized cellulose creates nanocomposites that mimic natural plant cell wall structures (Table 9.4). The preparation of these nanocomposites has aimed at studying the interactions of the components or at improving the functional properties of hemicellulose-based films, such as tensile strength or water vapour barrier properties. 

Extraction of botanical polysaccharides has traditionally been successfully carried out using the popular method of hot water extraction [1,2,5,71-77,85] and it is applicable in a variety of plant cell wall structures and water solubility of polysaccharide constitutes [65]. Briefly, the procedure involves large quantity of medicinal plant material/mushroom to be powdered, and then homogenized to maintain uniformity within and between the samples collected at different times. The powdered sample is then subjected to hot water extraction by autoclaving for approximately 2 h at 121 °C [5]. Autoclaved sample is filtered after allowing it to cool to room temperature, and the supernatant is then precipitated using 95% aqueous ethanol (supema-tant EtOH=l 4, v/v) for about 15 h at 2.5 °C to remove nonpolar... 

Secondary metabolites, produced by pathways derived from primary metabolic routes, are numerous and widespread, especially in higher plants. More than 20,000 were known in 1985 (Hartmann, 1985), and at least 1000 additional compounds, are described each year. In practice, the difference between the primary and secondary metabolites is fuzzy. Plant hormones such as gibberellic acid, indoleace-tic acid (auxin), ethylene, kinetin, and abscisic acid, as well as compounds involved in plant cell wall structure such as cinnamic acid and its polymeric derivative, lignin, are intermediate between primary and secondary metabolism (Birch, 1973). In some instances, compounds normally considered primary metabolites may accumulate in large amounts and behave in a manner usually associated with secondary metabolites. Entities such as shikimic acid and squalene, which initially were considered secondary metabolites, were subsequently shown to be important intermediates in the formation of primary metabolites (phenylalanine, tyrosine and tryptophan, and steroids, respectively). 

Pinelo, M Amous, A Meyer, AS. Upgrading of grape skins significance of plant cell-wall structural components and extraction techniques for phenol release. Trends Food Sci. Technol. 2006,17, 579-590. 

Figures 3 and 5 from Biochimie, vol 85, Perez S, Rodrigues-Carvajal MA, Doco T (2003) A complex plant cell wall polysaccharide rhamnogalactmonan 11. A structure in quest of a function. p 109-pl21...

Carpita N. Tierney M. Campbell M. (2001) Molecular biology of the plant cell wall Searching for genes that define structure, architecture and dynamics // Plant Mol. Biol. V. 47. P. 1- 5. 

Plant cell walls are made of bundles of cellulose chains laid down in a cross-hatched pattern that gives cellulose strength in all directions. Hydrogen bonding between the chains gives cellulose a sheetlike structure. 

Dietary fibre, which comprises all the non-digestible structural carbohydrates of plant cell walls and any associate lignin, provides a further example of a complex food-borne factor which cannot be classified as a nutrient, and which continues to generate debate over such issues as definition and analytical techniques. However, whatever the unresolved complexities, dietary fibre has a lengthy history and had proved itself eminently suitable as a component of functional food products long before the term was even coined. 

This study is the first report of the presence of rhamnogalacturonan n in fruit-derived products with the exception of the RG-n from wine [20]. Our RG-II preparations correspond very closely to the described model [1,13], confirming the conservation of its structure among plant cell walls. The complexity of the structure and composition of RG-II with several rare sugars uneasy to identify may be one possible explanation of why this fascinating molecule remained undetected in apple juices for such a long time. 

Shedletzky, E., Shmuel, M., Trainin, T., Kalman, S., and Delmer, D. (1992) Cell wall structure in cells adapted to growth on the cellulose-synthesis inhibitor 2,6-dichlorobenzonitrile. Plant Physiol. 100 120-130. 

The discovery of these enzymes enables a better structural characterisation of the hairy (ramified) regions of pectin, as already demonstrated by Schols et al. (1990b) and also of native plant cell wall pectin (Schols et al., 1995). In this study we show how the two exo-enzymes of the above described series, the RG-rhamnohydrolase and the RG-galacturonohydrolase, can be used as tools in the characterisation of unknown RG fragments. These unknown fragments were the products of RG-hydrolase or RG-lyase action toward linear RG oligomers (RGO s), which were produced by acid hydrolysis of sugar beet pulp. 

Pectin as one of the major plant cell wall constituents has received much attention both from a scientific and a technological point of view. Although pectin has been known to be a very complex heteropolysaccharide for quite some time, most progress on the elucidation of its structure has been attained in the last decade as a result of refinement and development of new more powerful techniques like HPAEC, HPGPC, NMR and the application of purified enzymes able to degrade specific parts of the complex molecule. 

---