The polysaccharide structure of potato cell walls: Chemical fractionation

Jarvis, Michael C.; Hall, Michael; Threlfall, David R.; Friend, J.

doi:10.1007/bf00391179

Cited by 142 publications

(76 citation statements)

References 31 publications

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“…The AG backbone may consist of separate blocks of galactan and arabinan, somewhat analogous to the alternating HG and RG blocks in pectin (but which, unlike those in pectin, contain no uronic acid). Reasons were given previously (4) (32), and cultured rose cell primary walls (12), from the results of analogous extraction procedures. Furthermore, although particular pectin molecules might be cross-linked by ester linkages as noted above, the pea pectin Mr profile clearly shows that its molecules are not interlinked extensively enough to form a network.…”

Section: Size Features Of Hemicellulosesmentioning

confidence: 99%

“…Certain authors (50,69), however, have held that no neutral arabinose or galactose polysaccharides have been isolated from primary walls by a procedure that could not have produced them artifactually by splitting side chains off of RG molecules. Jarvis et al (32) regarded extraction of pectins with oxalate-citrate, pH 4, at 100°C as slightly degradative. Their GFC evidence for this did not eliminate the alternative that this treatment caused some dissociation of large molecular aggregates rather than degradation.…”

Section: Size Features Of Hemicellulosesmentioning

confidence: 99%

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Molecular Size and Separability Features of Pea Cell Wall Polysaccharides

Talbott¹,

Ray²

1992

Plant Physiol.

188

129

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Relative molecular size distributions of pectic and hemicellulosic polysaccharides of pea (Pisum sativum cv Alaska) third intemode primary walls were determined by gel filtration chromatography. Pectic polyuronides have a peak molecular mass of about 1100 kilodaltons, relative to dextran standards. This peak may be partly an aggregate of smaller molecular units, because demonstrable aggregation occurred when samples were concentrated by evaporation. About 86% of the neutral sugars (mostly arabinose and galactose) in the pectin cofractionate with polyuronide in gel filtration chromatography and diethylaminoethyl-cellulose chromatography and appear to be attached covalently to polyuronide chains, probably as constituents of rhamnogalacturonans. However, at least 60% of the wall's arabinan/ galactan is not linked covalently to the bulk of its rhamnogalacturonan, either glycosidically or by ester links, but occurs in the hemicellulose fraction, accompanied by negligible uronic acid, and has a peak molecular mass of about 1000 kilodaltons. Xyloglucan, the other principal hemicellulosic polymer, has a peak molecular mass of about 30 kilodaltons (with a secondary, usually minor, peak of approximately 300 kilodaltons) and is mostly not linked glycosidically either to pectic polyuronides or to arabinogalactan. The relatively narrow molecular mass distributions of these polymers suggest mechanisms of co-or postsynthetic control of hemicellulose chain length by the cell. Although the macromolecular features of the mentioned polymers individually agree generally with those shown in the widely disseminated sycamore cell primary wall model, the matrix polymers seem to be associated mostly noncovalently rather than in the covalently interlinked meshwork postulated by that model. Xyloglucan and arabinan/galactan may form tightly and more loosely bound layers, respectively, around the cellulose microfibrils, the outer layer interacting with pectic rhamnogalacturonans that occupy interstices between the hemicellulose-coated microfibrils.The cell wall plays a critical role in plant cell enlargement. A wide range of growth-regulating agents, including both hormones and environmental factors, apparently act by modifying the ability of the primary wall to extend irreversibly.

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Section: Size Features Of Hemicellulosesmentioning

confidence: 99%

Section: Size Features Of Hemicellulosesmentioning

confidence: 99%

Molecular Size and Separability Features of Pea Cell Wall Polysaccharides

Talbott¹,

Ray²

1992

Plant Physiol.

188

129

View full text Add to dashboard Cite

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“…Exhaustive extraction for 24 h with 25% sodium hydroxide containing 5% sodium borate and 1% sodium borohydride (5) was attempted over the latter residue (EK). The extracts and the new residue (EN) were treated as above, and similar insoluble products were obtained: PDN (which precipitated during the dialysis), PCN (which precipitated during concentration), and PN (which precipitated between 40-50% ethanol concentration); 85% ethanol-soluble products were recovered as usual (SN).…”

Section: Extractionmentioning

confidence: 99%

Cell-Wall Carbohydrates of the Endosperm of the Seed of Gleditsia triacanthos

Manzi¹,

Ancibor²,

Cerezo³

1990

Plant Physiol.

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The endosperm of the seed of Gleditsia triacanthos L. contains 18.55% of its dry weight as nonreserve, cell-wall carbohydrates. Of this carbohydrate material, comprising mainly mannose, galactose, and glucose, 76.1% was of low-molecular weight or highly hydrophilic. Mannose, galactose, and glucose were also the major sugar components of the polysaccharides extracted with alkali (23.1% of the cell-wall), while the same sugars, with minor amounts of arabinose, form the residues. Methylation analysis of the polysaccharides and the borate-sodium hydroxide residue indicate that the cell walls are built up on a network of galactomannans, with high Man/Gal ratios, reinforced with minor amounts of cellulose.Gleditsia triacanthos is a dicot of the family Leguminosae, subfamily Caesalpinioideae. The seeds are albuminated, and the endosperm consists of a parenchymatic tissue of branched cells with thick primary walls containing as an incrustant, water-soluble reserve, galactomannans (8). These galactomannans consist of a ,3-(1 --4)-linked D-mannosyl backbone with a-( 1 -. 6)-linked stubs of D-galactose (4). Fine structural details modulate this gross structure in each case with possible consequences on the secondary structure, and on the formation of aggregates (8).To the best of our knowledge, no studies have been carried out on the composition of these primary cell walls, although the nature of its water-extractable polysaccharides and the specialized function of the endosperm suggest that this composition could be very different from those previously known (1, 10).We now report studies on the composition of the carbohydrates from the cell walls of the endosperm of the seeds of G. triacanthos. MATERIAL AND METHODS Plant MaterialThe seeds of Gleditsia triacanthos L. were obtained from ripe pods collected at the Ciudad Universitaria (Buenos Aires). The separation ofthe endosperm was performed as previously described (8).'This work was supported by a grant (PID 3005000/85) from the Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina). Microscopical ExaminationsThe endosperm tissue as well as that remaining after the different extraction procedures were examined by optical and scanning electron microscopy (SEM). ExtractionThe fractionation is shown in Scheme 1; products of each extraction and their yields are given in Table I. The endosperm (30 g) was treated with water (5 L) at 95°C for 24 h, three times immediately after milling (8). Further extraction in the same conditions (1 L) did not produce any carbohydrate material.The residue (EE) remaining after the aqueous extractions (18.5% based on dry weight) was exhaustively extracted with 7 M urea at room temperature with constant mechanical stirring for 8 h. The new residue (EU) was centrifuged off, and the extracts were combined and dialyzed against distilled water in a closed system for 48 h (DU). Presence of carbohydrates in the dialysis water was checked by the phenol-sulfuric acid method. The dialyzed extract was concentrated to 300 mL and sub...

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“…1 ,2) However, Jarvis et al: reported that there were two rhamnogalacturonan-based fractions in the potato cell wall. 3,4) The first fraction, extractable with a hot chelating solvent, was probably associated with other polysaccharides only through calcium-complexing and the steric effect of its own molecular size. The second fraction, extracted subsequently with mild alkali, was retained by covalent bonding.…”

mentioning

confidence: 99%

“…These two fractions showed a close similarity in the mode of linkages of sugar residues, although the latter was rich in galactan and arabinan side chains. 4 ) In the previous paper, we reported the structure of pectin isolated from tobacco midrib by extraction with EDTA.5) The pectin had a rhamnogalacturonan backbone to which side chains of galactan and arabinan were linked probably to C-4 of the L-rhamnosyl residues.…”

mentioning

confidence: 99%