Static and dynamic light-scattering studies of pectic polysaccharides from the middle lamellae and primary cell walls of cider apples

Pectic polysaccharides play an important role in the extracellular matrix of land plant tissues. Pectins are found in primary cell walls and in the connecting region between cells, the middle lamella. These polysaccharides are thought to function as a binding material within cell walls and between cells. Pectins contain galacturonosyl residues as a major constituent and varying amounts of neutral sugar residues. A portion of the galacturonosyl residues are methyl-esterlfted. Calcium salts of pectin are thought to be present in primary cell walls and middle lamella. The structure of the calcium bond between interfiber galacturonosyl residues has been suggested by x-ray fiber diffraction work. The pectic acid unit cell indicates that the galacturonosyl residue as viewed down the chain axis is roughly 7.2 x 6.8Å along the two crystallographlc a and b axes. One or two waters of hydration can Increase this size by 3-6Å In freeze-etched preparations or an associated calcium Ion can Increase Its cross-sectional dimensions by about 2Å.

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The Pectic Polysaccharides of Primary Cell Walls

Methods in Plant Biochemistry - Carbohydrates ◽

10.1016/b978-0-12-461012-5.50018-5 ◽

1990 ◽

pp. 415-441 ◽

Cited By ~ 214

Author(s):

MALCOLM O'NEILL ◽

PETER ALBERSHEIM ◽

ALAN DARVILL

Keyword(s):

Cell Walls ◽

Primary Cell ◽

Pectic Polysaccharides

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BIOSYNTHESIS AND DEGRADATION OF O-ACETYLATED PECTIC POLYSACCHARIDES IN PLANT PRIMARY CELL WALLS

XXIst International Carbohydrate Symposium 2002 ◽

10.1100/tsw.2002.404 ◽

2002 ◽

Author(s):

Caroline Orfila ◽

Florence Dal Degan ◽

Peter Ulvskov ◽

Henrik V. Scheller

Keyword(s):

Cell Walls ◽

Primary Cell ◽

Pectic Polysaccharides ◽

Plant Primary Cell Walls

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Uniformly 14C-labelled plant cell walls: Production, analysis and behaviour in rat gastrointestinal tract

British Journal Of Nutrition ◽

10.1079/bjn19930020 ◽

1993 ◽

Vol 69 (1) ◽

pp. 177-188 ◽

Cited By ~ 13

Author(s):

D. F. Gray ◽

S. C. Fry ◽

M. A. Eastwood

Keyword(s):

Gastrointestinal Tract ◽

Cell Walls ◽

Cultured Cells ◽

Spinacia Oleracea ◽

Primary Cell ◽

Polymer Composition ◽

Gut Contents ◽

Gut Microflora ◽

Plant Cell Walls ◽

Pectic Polysaccharides

Uniformly 14C-labelled primary cell walls (14C-PCW) were purified from suspension-cultured cells of spinach (Spinacia oleracea L.) grown in a medium containing D-[U-14C]glucose. The approximate polymer composition of the 14C-PCW preparation (% total 14C) was homogalacturonan 30,rhamnogalacturonan 23, xyloglucan 10, other hemicelluloses 3, cellulose 21, lignin 0,14C-labelled protein < 3 and [14C]starch < 2. The degree of methyl esterification of the pectic polysaccharides was about 25%. The 14C-PCW contained about 4% O-acetyl and 3% non-volatile ester-linked residues. When tracer levels of these 14C-PCW were fed to rats, only about 18% of the 14C appeared in the faeces;negligible levels of 14C (0.07%) remained in the gut contents 4 d after feeding. Some 14C was present in the carcass. The results show that U-14C-labelled primary cell walls can be purified and radiochemically analysed by the methods developed here, and that primary cell walls are extensively fermented by the gut microflora of the rat.

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