Cell walls polymer isolation

It has been stated mat me reactivity of the wood cell wall polymers to acetic anhydride decreases in me order lignin > hemicelluloses > cellulose, both within me wood cell wall (Rowell, 1982) and with me isolated polymers (Callow, 1951 Rowell etal., 1994 Efanov, 2001). A comprehensive series of NMR studies has been performed investigating me substitution of me cell wall polymeric OH groups at various WPGs (Ohkoshi and Kato, 1992, 1993, 1997a,b). These have shown that not all of me lignin OH groups are... 

Attachment of Hydroxycinnamic Acids to Structural Cell Wall Polymers. Peroxidase mediation may also result in binding the hydroxycinnamic acids to the plant cell wall polymers (66,67). For example, it was reported that peroxidases isolated from the cell walls of Pinus elliottii catalyze the formation of alkali-stable linkages between [2-14C] ferulic acid 1 and pine cell walls (66). Presumably this is a consequence of free-radical coupling of the phenoxy radical species (from ferulic acid 1) with other free-radical moieties on the lignin polymer. There is some additional indirect support for this hypothesis, since we have established that E-ferulic acid 1 is a good substrate for horseradish peroxidase with an apparent Km (77 /tM), which is approximately one fifth of that for E-coniferyl alcohol (400 /iM) (unpublished data). 

Isolation of the Biopolyesters. Cutin was obtained from the skin of limes using published methods (8,9). The final solvent extractions were omitted in studies of cutin-wax interactions. Typically, 20 limes provided 800 mg of powdered polymer. Suberized cell walls were isolated from wound-healing potatoes after seven days of growth (10), with a yield of 4.5 g from 22 kg of potatoes. Chemical depolymerization of both polyesters was accomplished via transesterification with BF3/CH3OH (11). 

The main function of the ester 34 in bacterial cells seems to be its participation in the biosynthesis of the glycopeptide cell-wall polymer. If this process is blocked, there results the accumulation of a high concentration of sugar nucleotide precursors in the cell. A number of these compounds have been isolated the simplest one is the ester of uridine 5 -pyrophosphate with N-acetylmuramic acid [2-acetamido-3-0-(D-l-carboxyethyl)-2-deoxy-D-glucose] (37), first obtained from Staphylococcus aureus cells that had been treated with penicillin7,151 or Gentian Violet.144 An intermediate in the biosynthesis of 37 was isolated and shown to be the 3 -enolpyruvate ether152,153 (38). 

Isolation ofPolymers from the Extracts. The solvents used for solubilizing the intracellular compounds would also solubilize a small proportion ( 6%) of the cell wall polymers from potatoes. These polymers could be isolated from the 1% SDC or 1.5% SDS, 0.5% SDC or SDS, PAW-, and DMSO-extracts. 

In this chapter an attempt has been made to discuss the methods available for the isolation and analysis of higher plant cell walls. Because the structures and properties of the cell wall polymers from various tissue tyjDes show considerable differences, it is emphasized that, where possible, separation of the tissues in a plant organ prior to preparation of the cell walls is desirable. Attention is drawn to the problems associated with coprecipitation of intracellular compounds with cell wall polymers, particularly in view of the occurrence of small amounts of proteoglycan and proteoglycan-polyphenol complexes in the walls and the covalent attachment of phenolics and phenolic esters with some of the cell wall polymers of parenchymatous and suspension-cultured tissues. The preparation of gram quantities of relatively pure cell walls from starch- and protein-rich tissues is discussed at some length because of the importance of dietary fiber in human nutrition and an understanding of the composition, structure, and properties of dietary fiber would be hampered without such methods (Selvendran, 1984). 

Boon JJ, Boer WRD, Kruyssen FJ, Wouters JTM. Pyrolysis mass spectrometry of whole cells, cell walls and isolated cell wall polymers oiBacillus subtilis var. Niger WM. J Gen Microbiol. 1981 122(l) 119-27. 

The S-layer protein SbsB reassembles into flat mono- and double-layer sheets with a size of 1-3 p.m [80]. The addition of the purified high molecular weight secondary cell wall polymer which functions as an anchoring structure for the S-layer protein in the bacterial cell wall [81] inhibited the in vitro self-assembly of the isolated S-layer protein and kept it in the water-soluble state. Interestingly, the soluble monomeric and/or oligomeric S-layer protein recrystallized into closed monolayers on poly-L-lysine coated EM-grids to which the S-... 

This review has stressed the need to isolate and chemically characterize the structures of the polymers of primary cell walls. Emphasis must be placed on working with cell wall polymers rather than with polymers obtained from other tissues and organelles. It is also important to obtain polymers from homogeneous preparations of primary cell walls rather than from walls isolated from tissues containing a mixture of wall types. Much of the early work on characterizing cell wall polymers was done with heterogeneous wall preparations. The availability of easily... 

The fiber-rich product constituted by dried quince Cydonia oblonga Miller) wastes (M-fraction), as well as those fractions essentially constituted by the water insoluble (MA) or the ethanol insoluble (MEq) dried residues were analyzed. The latter product was mainly constituted by the cell wall polymers of quince cellular residues since it is known that the direct treatment of a vegetable sample with hot ethanol produces the isolation of the cell wall material (Stevens and Selvendran, 1980). 

AGX are also the dominant hemicelluloses in the cell walls of hgnified supporting tissues of grasses and cereals. They were isolated from sisal, corncobs and the straw from various wheat species [4]. A more recent study on corncob xylans [30] showed the presence of a hnear, water-insoluble polymer... 

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