Pectic polysaccharides of growing plant tissues

Stoddart, R. W.; Barrett, A. J.; Northcote, D. H.

doi:10.1042/bj1020194

Cited by 120 publications

(31 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Pectic polysaccharides can be classified in two groups, a hot water-soluble form and a chelating agent-soluble one, on the basis of a difference in the extractability from the cell wall materials. Hexametaphosphate solution is an effective Ca2+-binding agent at acidic pH, and causes only little degradation of pectic polysaccharide structure during the extraction from cell walls of sycamore callus and apple fruit (22). Therefore, pectic polysaccharides from cucumber cell walls grown with or without Ca2" were studied after extraction successively by a hot water and hexametaphosphate solution.…”

Section: Resultsmentioning

confidence: 99%

Pectic Polysaccharide Breakdown of Cell Walls in Cucumber Roots Grown with Calcium Starvation

et al. 1984

View full text Add to dashboard Cite

Pectic polysaccharides from the roots of cucumber (Cucumis sativus L.) grown in liquid culture medium with or without calcium (1 mM CaCl2) were studied after extraction successively by hot water and Na hexametaphosphate solution. The Ca2 starvation-treatment caused a striking reduction in content ofextracted pectic polysaccharide; from an equivalent weight of cell walls, only 33.1% of the control level was extracted from root cell walls of plants cultured under Ca2' deficiency. The extracted pectic polysaccharides were fractionated into neutral and acidic polymers by a DEAE-Sephadex column. The acidic polymers, which represented more than 76% of the yield, appeared to be a major fraction of extracted pectic polysaccharides. The changes of molecular size and glycosyl residue composition of this fraction were compared for the control and Ca2l-deprived samples. The results indicate that Ca22 deficiency caused structural changes which could involve both branching pattern and extent of contiguous galacturonosyl units in the water-solubilized pectic polysacchardes. Ca2* starvation also led to a notable decrease in molecular size of the hexametaphosphate-solubilized polysaccharides and, to a lesser extent, of the water-solubilized fraction as well. In addition, polygalacturonaw activity in tissue homogenates increased remarkably with the Ca2' deficiency, whereas -pgalactosidase activity did not undergo a change. Thus, it appears that one major effect of Ca2 deprivation was to stimulate polygalacturonase activity, an effect which could be involved in the control of the breakdown of pectic polysaccharides in the cell walls. Calcium (Ca2+) is an essential nutrient for plant growth and plays a crucial role in regulating many physiological functions (3, 6). One of the principle functions proposed for Ca2+ concerns its role in structural organization during cell division and enlargement (elongation), but the mechanism of participation is still controversial. Plant growth depends on the change in mechanical structure of cell walls, a process which could involve alterations in amount and/or structure of pectic polysaccharides serving structural elements of cell walls. For many years, the suggestion has been made (5, 23) that the presence of Ca2l in the pectic polysaccharide matrix could be important in the strength of the cell wall structure (the Ca2l-bridge hypothesis) and for the inhibition ofthe breakdown of pectic polysaccharides during growth. In recent studies, Rees and co-workers (9,17,19) Preparation of Cell Walls and Pectic Polysaccharides. Whole cucumber roots were harvested, rinsed, dried with filter paper, and weighed. The root tissues (30-50 g fresh weight) were homogenized in 0.1 M K-phosphate buffer (pH 7.0) containing 9 mM 2-mercaptoethanol and 2.0 M NaCl using a Waring Blendor (at 17,000 rpm; model AM-3, Nissei Ltd., Japan) for 3 min at 0°C. The homogenate was stirred for 2 h at 0°C and filtered with a sintered glass filter under suction; the filtrate was discarded. The cell walls were isolated fro...

show abstract

Section: Resultsmentioning

confidence: 99%

Pectic Polysaccharide Breakdown of Cell Walls in Cucumber Roots Grown with Calcium Starvation

et al. 1984

View full text Add to dashboard Cite

show abstract

“…The aldobiuronic acid galacturonosyl-(l -> 2)-rhamnose has been isolated from the pectic polysaccharides of a number of plants (11,13,14,56,61). The following experiment demonstrates that this is the most abundant aldobiuronic acid of sycamore cell walls.…”

Section: Composition Of the Total Cell Wallmentioning

confidence: 89%

The Structure of Plant Cell Walls

Talmadge¹,

Keegstra²,

Bauer³

et al. 1973

Plant Physiol.

500

162

View full text Add to dashboard Cite

This is the first in a series of papers dealing with the structure of cell walls isolated from suspension-cultured sycamore cells (Acer pseudoplatanus) . These studies have been made possible by the availability of purified hydrolytic enzymes and by recent improvements in the techniques of methylation analysis. These techniques have permitted us to identify and quantitate the macromolecular components of sycamore cell walls. These walls are composed of 10% arabinan, 2% 3,6-linked arabinogalactan, 23% cellulose, 9 % oligo-arabinosides (attached to hydroxyproline), 8% 4-linked galactan, 10% hydroxyproline-rich protein, 16 % rhamnogalacturonan, and 21% xyloglucan.The structures of the pectic polymers (the neutral arabinan, the neutral galactan, and the acidic rhamnogalacturonan) were obtained, in part, by methylation analysis of fragments of these polymers which were released from the sycamore walls by the action of a highly purified endopolygalacturonase. The data suggest a branched arabinan and a linear 4-linked galactan occurring as side chains on the rhamnogalacturonan. Small amounts or pieces of a xyloglucan, the wall hemicellulose, appear to be covalently linked to some of the galactan chains. Thus, the galactan appears to serve as a bridge between the xyloglucan and rhamnogalacturonan components of the wall.The rhamnogalacturonan consists of an a-(1 -; 4)-linked galacturonan chain which is interspersed with 2-linked rham. nosyl residues. The rhamnosyl residues are not randomly distributed in the chain but probably occur in units of rhamnosyl-(1 -4 4)-galacturonosyl-(1 -e 2)-rhamnosyl. This sequence appears to alternate with a homogalacturonan sequence containing approximately 8 residues of 4-linked galacturonic acid. About half of the rhamnosyl residues are branched, having a substituent attached to carbon 4. This is likely to be the site of attachment of the 4-linked galactan.The hydroxyprolyl oligo-arabinosides of the hydroxyproline. rich glycoprotein contain 3-linked, 2-linked, and terminal arabinosyl residues. The structure of the hydroxyprolyl oligoarabinosides deduced from our methylation studies agrees with the structure reported for similar oligosaccharides. Cellulose, hemicellulose, pectic polysaccharide, structural protein, and lignin have been identified as the major components of the plant cell wall. These components have been discussed in several recent reviews (4,9,26,35,47,52,63,64,68). Lignin is a characteristic component of secondary walls and is therefore not further discussed.Crystalline cellulose fibers make up an important part of the framework of the cell walls of all higher plants. Electron microscopy and x-ray diffraction have led to a rather detailed description of the structure of this wall component (35,57,69

show abstract

“…spectrum of pectin J' showed significant absorption at 235 mp indicative of unsaturated uronic acid residues (4) which absorption was absent in pectin A. When a sample of pectin A was heated with a solution of sodium hexametaphosphate in which the p H was adjusted to 3.7 the recovered polysaccharide showed no change in electrophoretic mobility (2).…”

Section: Trenftnet~f Of Pecfitz a Under Condifiot~s Of Furthermentioning

confidence: 99%

Lemon-peel pectin. II. Isolation of homogeneous pectins and examination of some associated polysaccharides

Aspinall¹,

Cottrell²

1970

Can. J. Chem.

View full text Add to dashboard Cite

Two electrophoretically homogeneous pectins have been isolated from dried lemon-peel under conditions of minimum degradation by extraction with cold water and with disodium ethylenediaminetetraacetate. Some properties of polysaccharides which occur in association with the pectins are reported.Canadian Journal of Chemistry, 48, 1283Chemistry, 48, (1970 Previous studies on dried lemon-peel (1) have shown that extraction under the mildest possible conditions, namely with water at room temperature, furnishes pectin A which, after chromatography on diethylaminoethyl-Sephadex, may be obtained in chemically homogeneous form as pectin C. This pectin was shown to contain 75 % of galacturonic acid residues, of which approximately 80% were esterified. Neutral sugars, including galactose, arabinose, rhamnose, xylose, and fucose, were present as constituents, and characterization of oligosaccharides formed on depolymerization provided direct evidence for the structural role of rhamnose and xylose residues in the acidic polysaccharide. The waterextracted pectin, however, accounts for only about a third of the total pectin in the peel, and we now report the extraction of a second homogeneous pectin, under non-degradative conditions, together with an examination of certain structural features of polysaccharides which occur in association with pectin C.Dried lemon-peel was extracted with water at room temperature, as described previously (I), to give pectin A together with a polysaccharide fraction from which polysaccharide F was isolated. Pectin A gave a single peak on electrophoresis in pyridine -acetic acid buffer (Fig. I), but two minor peaks were detected in addition to the main peak in borate buffer (Fig. 2). Fractionation of pectin A by chromatography on diethylaminoethyl-Sephadex furnished electrophoretically homogeneous pectin C (Fig. 3), and small amounts of polysaccharide fractions D and E. Partial acid hydrolysis of pectin C afforded inter alia acidic oligosaccharides with the chromatographic mobilities of 2-0-(a-D-galactopyranosyl-ranosyluronic acid)-L-fucose, and 6-0-(P-D-glucopyranosyluronic acid) -D -galactose, thus providing further evidence that these oligosaccharides were genuine fragments from the pectin and did not arise solely from associated polysaccharides.Samples of water-extracted lemon-peel were further extracted at 90" with (i) water acidified to p H 2.1, (ii) disodium ethylenediaminetetraacetatelsodium lauryl sulfate at p H 5,' and (iii) sodium hexametaphosphate at p H 4.2 to give pectins G, H, and J (see Table 1). Pectins G and H were essentially identical in composition, but in each case electrophoresis showed that the major component was contaminated with a component of the same mobility as pectin C. Control experiments showing that treatment of pectin A under extraction conditions (i) and (ii) caused no change in electrophoretic mobility indicated that the two components in pectins G and H are not artifacts arising from the extraction procedures. Pectin J, however, had a much higher electrophor...

show abstract

Pectic polysaccharides of growing plant tissues

Cited by 120 publications

References 25 publications

Pectic Polysaccharide Breakdown of Cell Walls in Cucumber Roots Grown with Calcium Starvation

Pectic Polysaccharide Breakdown of Cell Walls in Cucumber Roots Grown with Calcium Starvation

The Structure of Plant Cell Walls

Lemon-peel pectin. II. Isolation of homogeneous pectins and examination of some associated polysaccharides

Contact Info

Product

Resources

About