Publisher Summary This chapter describes the methods used for isolating and characterizing the noncellulosic polysaccharides of the primary walls of suspension-cultured sycamore cells These procedures are applicable to the study of other types of cell walls Cell walls form the basic structural framework of the plant, defining the shape and size of plant cells and tissues Cell walls are classified as either primary or secondary, depending upon their mechanical properties and chemical composition The primary cell wall is a mechanically dynamic structure encasing the cell during the period of rapid expansion that follows cell division The secondary cell wall is, relative to the primary cell wall, a mechanically static structure that determines the shape and size of the mature cell The chapter presents the experiments for the isolation of plant cell walls and the isolation of polysaccharides from cell walls and from extracellular polysaccharides of suspension-cultured plant cells and the chemical methods used for characterizing polysaccharides

Isolation and characterization of plant cell walls and cell wall components

8 – Structure and Function of Plant Cell Walls

Since the beginning of this century, Goji berries and juice are being sold as health food products in western countries and praised in advertisements and in the media for well-being and as an anti-aging remedy. The popularity of Goji products has rapidly grown over the last years thanks to efficient marketing strategies. Goji is a relatively new name given to Lycium barbarum and L. chinense, two close species with a long tradition of use as medicinal and food plants in East Asia, in particular in China. While only L. barbarum is officinal, the fruit (fructus Lycii) and the root bark (cortex Lycii radicis) of both species are used in the folk medicine. We review here the constituents, pharmacology, safety, and uses of L. barbarum and L. chinense with consideration to the different parts of the plant. Investigations of the fruit have focused on proteoglycans, known as " Lycium barbarum polysaccharides", which showed antioxidative properties and some interesting pharmacological activities in the context of age related diseases such as atherosclerosis and diabetes. As to the root bark, several compounds have demonstrated a hepatoprotective action as well as inhibitory effects on the rennin/angiotensin system which may support the traditional use for the treatment of hypertension. While there are no signs of toxicity of this plant, two cases of possible interaction with warfarin point to a potential risk of drug interaction. In view of the available pharmacological data and the long tradition of use in the traditional Chinese medicine, L. barbarum and L. chinense certainly deserve further investigation. However, clinical evidences and rigorous procedures for quality control are indispensable before any recommendation of use can be made for Goji products.

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Goji (Lycium barbarum and L. chinense): Phytochemistry, pharmacology and safety in the perspective of traditional uses and recent popularity.

After the context is set by a brief description of the plant cell surface, emphasis is placed on one class of cell surface components, the arabinogalactan proteins. An expansion of knowledge regarding the structure, expression, and function of these proteoglycans has been initiated and is being sustained through new experimental approaches, including the development of monoclonal antibody probes and the cloning of cDNAs corresponding to core polypeptides. An examination of the structure of both the polypeptide and carbohydrate components of arabinogalactan proteins is presented with emphasis placed on recently deduced core polypeptide sequences. Information about the biosynthesis and turnover of arabinogalactan proteins is incomplete, especially with regard to the carbohydrate component. Although functions of arabinogalactan proteins have not been clearly identified, regulated expression and several other lines of evidence point to involvement in plant reproductive development, pattern formation, and somatic embryogenesis, as well as in the underlying processes of cell division, cell expansion, and cell death. Arabinogalactan proteins are compared with animal proteoglycans and mucins, and the results of searches for plant analogues of other animal extracellular matrix components are examined.

Proteoglycans and Related Components in Plant Cells

After thermal degradation of wood the lignin degradation products were separated by gas chromatography and identified by mass spectrometry. The mass spectra and chemical formulae of 82 monomeric lignin derived degradation products are presented.

Thermal degradation products of wood. A collection of electron-impact (EI) mass spectra of monomeric lignin derived products

(1984). Gum Arabic is a Kind of Arabinogalactan–Protein. Agricultural and Biological Chemistry: Vol. 48, No. 1, pp. 235-237.

Kunio Katō

Papers

Gum Arabic is a Kind of Arabinogalactan–Protein

Structural investigation of the arabinoxyloglucan from Nicotiana tabacum

A stereoselective synthesis of “natural” (4S,6S,7S)-serricornin, the sex pheromone of cigarette bettle, from levoglucosenone

Pyrolytic formation of 3-hydroxy-2-penteno-1,5-lactone from xylan, xylo-oligosaccharides, and methyl xylopyranosides

A galactoglucomannan from cell walls of suspension-cultured tobacco (Nicotiana tabacum) cells