Suspension-cultured tissues, cell wall preparation

Preparation of Cell Wall Material from Suspension-Cultured Tissues... 

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). 

Success in structural studies of cell walls depends largely on the purity and homogeneity of the cell wall preparations examined. Some studies have been made of primary cell walls extracted from whole plant tissues. Since all tissues of intact plants contain a variety of cell types, the walls prepared from these tissues are not homogeneous. The desire for homogeneous wall preparations has been satisfied by use of suspension-cultured cells. Suspension-cultures, of at least some types of plant cells, can be maintained in a totally undifferentiated state. These types of suspension cultures provide a source of homogeneous primary cell walls. 

Suspension-cultured plant cells represent a somewhat artificial situation since one is interested in studying the cells of the intact plant. The structures of the walls of cells in culture and the walls of cells in the plant may conceivably differ and it is essential when studying suspension-cultured cells to keep this possibility in mind. However, the available data indicate that the walls of suspension-cultured cells are very similar in structure to the walls of intact plant tissues. Cell wall glycosyl and glycosyl-linkage compositions of pea (58) and red kidney bean (105) hypocotyl tissues show that these tissues contain walls which are very similar to the walls isolated from suspension-cultured sycamore (123) and suspension-cultured red kidney bean cells (105). In addition, it has been demonstrated that the primary walls of cambial cells which were prepared from the branches of sycamore trees are very similar to the walls of suspension-cultured sycamore cells (104). 

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