Determination of methanol and its application to measurement of pectin ester content and pectin methyl esterase activity

Wood, Peter; Siddiqui, Iqbal R.

doi:10.1016/0003-2697(71)90432-5

Cited by 319 publications

(137 citation statements)

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“…Total UA content (1) and the degree of esterification (31) of the cell walls were determined after dehydrating native walls with acetone followed by vacuum drying. Soluble UA were measured according to Blumenkrantz and Asboe-Hansen (4).…”

Section: Analysis Of Wall Carbohydrate Componentsmentioning

confidence: 99%

“…The degree of polymer methylesterification was monitored according to Wood and Siddiqui (31). Because ofthe presence of a-amylase in the PE preparation, cell walls residues were washed with 20 mL of the incubation buffer over a 30 ,um nylon mesh to remove products of starch digestion.…”

Section: Pe Pretreatment Of Hcwmentioning

confidence: 99%

“…Substantial PG activity might be preserved during the chloroform-methanol and acetone dehydration of the tissue or alternatively, substantial ,-elimination occurs. The fact that only 1 mg UA/100 mg wall is solubilized from H-CM walls (Table I) (24,28,31). Differences in extraction methodology may explain this discrepancy.…”

Section: Buffer Soluble Pectin Contentmentioning

confidence: 99%

“…Heat and alkali treatments mediate ,-elimination reactions which reduce overall polymer length (2,16). Furthermore, alkaline pH can deesterify methyl groups (31) and associated phenolics (7) from the polysaccharide. Treatment of cell walls with organic solvents such as chloroform and acetone dehydrate the cell wall.…”

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Tomato Fruit Cell Wall

Koch

Nevins²

1989

Plant Physiol.

151

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Cell wall isolation procedures were evaluated to determine their effect on the total pectin content and the degree of methylesterification of tomato (Lycopersicon esculentum L.) fruit cell walls. Water homogenates liberate substantial amounts of buffer soluble uronic acid, 5.2 milligrams uronic acid/100 milligrams wall. Solubilization appears to be a consequence of autohydrolysis mediated by polygalacturonase 11, isoenzymes A and B, since the uronic acid release from the wall residue can be suppressed by homogenization in the presence of 50% ethanol followed by heating. The extent of methylesterification in heatinactivated cell walls, 94 mole %, was significantly greater than with water homogenates, 56 mole %. The results suggest that autohydrolysis, mediated by cell wall-associated enzymes, accounts for the solubilization of tomato fruit pectin in vitro. Endogenous enzymes also account for a decrease in the methylesterification during the cell wall preparation. The heat-inacffvated cell wall preparation was superior to the other methods studied since it reduces,-elimination during heating and inactivates constitutive enzymes that may modify pectin structure. This heat-inactivated cell wall preparation was used in subsequent enzymatic analysis of the pectin structure. Purified tomato fruit polygalacturonase and partially purified pectinmethylesterase were used to assess changes in constitutive substrates during tomato fruit ripening. Polygalacturonase treatment of heat-inactivated cell walls from mature green and breaker stages released 14% of the uronic acid. The extent of the release of polyuronides by polygalacturonase was fruit development stage dependent. At the tuming stage, 21% of the pectin fraction was released, a value which increased to a maximum of 28% of the uronides at the red ripe stage. Pretreatment of the walls with purified tomato pectinesterase rendered walls from all ripening stages equally susceptible to polygalacturonase. Quantitatively, the release of uronides by polygalacturonase from all pectinesterase treated cell walls was equivalent to polygalacturonase treatment of walls at the ripe stage. Uronide polymers released by polygalacturonase contain galacturonic acid, rhamnose, galactose, arabinose, xylose, and glucose. As a function of development, an increase in the release of galacturonic acid and rhamnose was observed (40 and 6% of these polymers at the mature green stage to 54 and 15% at the red ripe stage, respectively). The amount of galactose and arabinose released by exogenous polygalacturonase decreased during development (41 and 11% from walls of mature green fruit to 11 and 6% at the red ripe stage, respectively). Minor amounts of glucose and xylose released from the wall by exog- ' Supported, in part, by a gift from Chesebrough-Ponds Inc.

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Section: Analysis Of Wall Carbohydrate Componentsmentioning

confidence: 99%

Section: Pe Pretreatment Of Hcwmentioning

confidence: 99%

Section: Buffer Soluble Pectin Contentmentioning

confidence: 99%

mentioning

confidence: 99%

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Tomato Fruit Cell Wall

Koch

Nevins²

1989

Plant Physiol.

151

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“…For ORS 2060, the 40 h and 70 h 100 mM methanol samples were also of 40 185 µl. The samples were oxidized with potassium permanganate, excess permanganate 186 removed with sodium arsenite (Wood & Siddiqui, 1971), and formaldehyde 187 concentration determined by measuring OD 412 190 after reaction with Nash's reagent 188 (Nash, 1953). respectively.…”

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confidence: 99%

Root nodule bacteria isolated from South African Lotononis bainesii, L. listii and L. solitudinis are species of Methylobacterium that are unable to utilize methanol

et al. 2009

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are being studied because of their potential as well-adapted pasture legumes able to 20 combat dryland salinity in southern Australian agricultural systems (Yates et al., 21 2007). The genus Lotononis is of mainly southern African origin, comprising some 22 150 species of herbs and small shrubs (Van Wyk, 1991). Species in the Listia section 23 are of particular interest, as they are perennial, stoloniferous and lack the poisonous 24 metabolites found in some other species of Lotononis (Van Wyk & Verdoorn, 1990). 25 (Norris, 1958; Yates et al., 2007). 29 30The root nodule bacteria from L. bainesii were first described by Norris (1958), who 31 reported that isolates from L. bainesii were red-or pink-pigmented and that the 32 symbiosis was highly specific. These pigmented bacteria were subsequently 33 characterized and identified as a species of Methylobacterium (Jaftha et al., 2002 Free-living methylobacteria are found in a variety of habitats, such as soil, dust, and 42 fresh water (Green, 1992). Methylobacteria are also ubiquitous in the plant 43 4 phyllosphere and rhizosphere (Trotsenko et al., 2001 (Basile et al., 1985; Holland & Polacco; 1994 , Ivanova et al., 2000 47 Trotsenko et al., 2001; Madhaiyan et al., 2004; Abanda-Nkpwatt et al., 2006; Ryu et 48 al., 2006). The closeness of the association between plants and Methylobacterium 49 spp. varies; epiphytes (Omer et al., 2004;), endophytes (Van Aken et al., 2004) and 50 nitrogen-fixing symbionts (Sy et al., 2001; Jaftha et al., 2002; Yates et al., 2007), 51 have all been described. 52Methylobacterium spp. are characterized by their ability to utilize methanol and other 54 C 1 compounds, as well as a variety of multicarbon substrates (Green, 1992; Lidstrom, 55 2006). Utilization of carbohydrates as a sole carbon source is variable and can be 56 used to differentiate the various species (Green, 1992). Methylotrophy in 57 Methylobacterium spp. involves over 100 genes constituting a set of metabolic 58 functional modules (Chistoserdova et al., 2003). In the model organism 59Methylobacterium extorquens AM1, such modules involve the primary oxidation of 60 methanol or methylamine to formaldehyde, the oxidation of formaldehyde, and the 61 assimilation of C 1 products via the serine cycle (Chistoserdova et al., 2003; Lidstrom, 62 2006). Methanol is oxidized by methanol dehydrogenase (MDH), a protein with an 63 α 2 β 2 tetramer structure, a pyrroloquinoline quinone (PQQ) cofactor and a calcium 64 ion, essential for maintaining the PQQ in its active configuration, in the active site of 65 each α-subunit (Anthony, 1996; Goodwin & Anthony, 1998). The genes encoding the 66 MDH structural polypeptides, the specific cytochrome c electron acceptor, proteins 67 essential for the insertion of the calcium ion, a regulatory protein and several proteins 68 5 of unknown function are transcribed in a single operon, mxaFGIRSACKLDEHB 69 (Chistoserdova et al., 2003). 70 71The M. nodulans isolates from Crotalaria, like all previously described 72Methylobacterium spe...

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Developmental and Ripening-Related Effects on the Cell Wall of Pepino (Solanum muricatum) Fruit

O’Donoghue¹,

Somerfield²,

Vre³

et al. 1997

J. Sci. Food Agric.

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Several cell wall components in ripening pepino fruit have been quantitatively and qualitatively characterised, with the aim of identifying their contributions to the loss of tissue firmness. Pepinos were graded into nine groups based on progressive, characteristic skin colour changes, previously shown to correspond with decreasing fruit firmness. While fruit softening began when the pepinos were still green but with newly acquired purple stripes, the first significant quantitative signs of cell wall modification (total pectin and hemicellulose content declining and CDTA‐soluble pectin content increasing, on a fresh weight basis) were detectable later in ripening, when the fruit began to acquire yellow skin pigmentation. Gel fractionation studies demonstrated that there were increased levels of low‐molecular‐weight pectin and xyloglucan during pepino ripening. The change in molecular weight distribution of CDTA‐soluble pectin occurred as fruit started to acquire yellow pigmentation, while xyloglucan polymers were modified at an earlier stage that coincided with the initial loss of firmness. © 1997 SCI.

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Determination of methanol and its application to measurement of pectin ester content and pectin methyl esterase activity

Cited by 319 publications

References 9 publications

Tomato Fruit Cell Wall

Tomato Fruit Cell Wall

Root nodule bacteria isolated from South African Lotononis bainesii, L. listii and L. solitudinis are species of Methylobacterium that are unable to utilize methanol

Developmental and Ripening-Related Effects on the Cell Wall of Pepino (Solanum muricatum) Fruit

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