Types of Cell Wall Polysaccharides

Early workers considered the wall to be composed of three polysaccharide fractions namely cellulose, the hemicelluloses and the pectic polysaccharides. Grouped in the pectic fraction are all of the polysaccharides extracted from cell walls by hot water, ammonium oxalate, weak 

The original classification of wall polysaccharides can be related to the modem terminology, as mild acid preferentially extracts the pectic polysaccharides, while subsequent extraction with alkali preferentially solubilizes the hemicelluloses. Therefore, in this review, discussion of the non-eellulosic cell wall polysaccharides will be found under the general headings of the pectic polysaccharides and the hemicelluloses. Cellulose as well as the non-polysaccharide components of primary cell walls will also be considered. 

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In the following sections we shall briefly illustrate the types of cell wall polysaccharides that have been enzymically degraded as an aid to structural analysis. 

The next step is to select a protocol for isolating cell walls that suits the type of material to be investigated and the reasons for doing the research (see Critical Parameters). Two basic protocols are described, one for plant tissue that does not contain starch (see Basic Protocol 2) and one for plant tissue that does contain starch (see Basic Protocol 3), as well as three alternate protocols that can be used and modified to suit (see Commentary). The final step is fractionation of cell wall polysaccharides, which is a sequential chemical extraction of polysaccharides from the walls (see Basic Protocol 4). Table E3.1.1 provides a more detailed description of the protocols presented in this unit. 

In Volume 33 of this Series, we presented1 a review of the crystalline structures of polysaccharides published during the period 1967-1974. Detailed accounts of progress in structural studies on specific types of polysaccharides were presented in the Proceedings of the Twenty-sixth Symposium of the Colston Research Society and were subsequently published as a book.2 Precise methods for X-ray diffraction analysis of biopolymer structures were discussed by Hukins.3 The aspects of the structures of cellulose, mannan, and xylan, their organization in the cell wall, and the biosynthesis of cell-wall polysaccharides were described by Mackie.4 Work on the structures of the connective-tissue polysaccharides, O-acetylcellulose, and the various forms of amylose was reviewed by Atkins,5 Chanzy,6 and Sarko,7... 

Musher DM, Luchi M, Watson DA, Hamilton R, Baughn RE. Pneumococcal polysaccharide vaccine in young adults and older bronchitics determination of IgG responses by ELISA and the effect of adsorption of serum with non-type-speciflc cell wall polysaccharide. J Infect Dis 1990 161 728-735. 

Based on the current stage of knowledge, hemicelluloses can be divided into four general classes of structurally different cell-wall polysaccharide types, i.e.,... 

The pectin network.-The second polysaccharide network present in primary cell walls is composed of pectic polysaccharides. The pectin network appears to coexist with the cellulose/hemicellulose network, that is, both networks appear to be able to share the same space [16-19]. However, the proportions of the two networks appear to vary from location to location within a single cell wall as well as from the primary wall of one type of cell to the primary wall of a another type of cell [9,20-22]. 

Extrusion-cooking of cell-wall rich products (e.g. wheat bran, apple pomace, citrus peels, sugar-beet pulp, pea hulls.) led to an important solubilisation of polysaccharides of various types without extensive degradation of the polymeric structure. The possibility of obtaining gelled systems directly with the extruded pectin-rich materials was demonstrated. 

Myeloma proteins occur in animal tumors of various types. The synthesis of these proteins can be induced in some experimental animals by injection of mineral oil, or the implantation of plastic discs.161 Myeloma proteins were shown to possess antibody activity, with specificity for different types of substances.161 Some of these proteins were found to combine with such carbohydrates as bacterial, cell-wall polysaccharides, lipopolysaccharides, dextrans, levans, and galactans.162 Myeloma proteins that combine with galactans or dextrans possess anti-galactan activity,163,164 or anti-dextran activity,165-167 and have been studied most extensively. 

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