Amounts Of Galacturonic Acid Research Articles

Pulvinar slits: Cellulose-deficient and de-methyl-esterified pectin-rich structures in a legume motor cell.

The cortical motor cells (CMCs) in a legume pulvinus execute the reversible deformation in leaf movement that is driven by changes in turgor pressure. In contrast to the underlying osmotic regulation property, the cell wall structure of CMCs that contributes to the movement has yet to be characterized in detail. Here, we report that the cell wall of CMCs has circumferential slits with low levels of cellulose deposition, which are widely conserved among legume species. This structure is unique and distinct from that of any other primary cell walls reported so far; thus, we named them "pulvinar slits." Notably, we predominantly detected de-methyl-esterified homogalacturonan inside pulvinar slits, with a low deposition of highly methyl-esterified homogalacturonan, as with cellulose. In addition, Fourier transform infrared spectroscopy analysis indicated that the cell wall composition of pulvini is different from that of other axial organs, such as petioles or stems. Moreover, monosaccharide analysis showed that pulvini are pectin-rich organs like developing stems and that the amount of galacturonic acid in pulvini is greater than in developing stems. Computer modeling suggested that pulvinar slits facilitate anisotropic extension in the direction perpendicular to the slits in the presence of turgor pressure. When tissue slices of CMCs were transferred to different extracellular osmotic conditions, pulvinar slits altered their opening width, indicating their deformability. In this study, we thus characterized a distinctive cell wall structure of CMCs, adding to our knowledge of repetitive and reversible organ deformation as well as the structural diversity and function of the plant cell wall.

Reduced photosynthesis in Arabidopsis thaliana atpme17.2 and atpae11.1 mutants is associated to altered cell wall composition.

The cell wall is a complex and dynamic structure that determines plants' performance by constant remodeling of its compounds. Although cellulose is its major load-bearing component, pectins are crucial to determine wall characteristics. Changes in pectin physicochemical properties, due to pectin remodeling enzymes (PRE), induce the rearrangement of cell wall compounds, thus, modifying wall architecture. In this work, we tested for the first time how cell wall dynamics affect photosynthetic properties in Arabidopsis thaliana pectin methylesterase atpme17.2 and pectin acetylesterase atpae11.1 mutants in comparison to wild-type Col-0. Our results showed maintained PRE activities comparing mutants with wild-type and no significant differences in cellulose, but cell wall non-cellulosic neutral sugars contents changed. Particularly, the amount of galacturonic acid (GalA) - which represents to some extent the pectin cell wall proportion - was reduced in the two mutants. Additionally, physiological characterization revealed that mutants presented a decreased net CO2 assimilation (AN ) because of reductions in both stomatal (gs ) and mesophyll conductances (gm ). Thus, our results suggest that atpme17.2 and atpae11.1 cell wall modifications due to genetic alterations could play a significant role in determining photosynthesis.

Towards By-Product Utilisation of Pea Hulls: Isolation and Quantification of Galacturonic Acid.

In order to evaluate by-products from food processing as alternative raw materials for pectin extraction, their amount of galacturonic acid (GalA) has to be analysed as a marker for pectin content. In the present study, significant differences in GalA release using different digestion methods are shown for pea hulls, as an example of by-products with a high content of cellulose. Complete digestion of the fibre matrix was assumed for Saeman hydrolysis as a reference protocol. Significantly lower GalA release was achieved by a treatment with trifluoracetic acid (TFA). An alternative treatment with ethylenediaminetetraacetic acid (EDTA) at pH 11 followed by an enzymatic digestion at pH 4.5 using a combination of polygalacturonase (Vegazyme M) and cellulase (Celluclast 1.5L) resulted in a similar release of GalA compared to Seaman hydolysis. Pea hull samples, analysed by this alternative protocol, showed on average a GalA content of 11.2%. Therefore, pea hulls may serve as new raw material for pectin extraction.

Discussion and Analysis of <em>Flammulina velutipes Polysaccharides</em> Compositions, Molecular Weight and Monosaccharide Composition

The aim of the present work was to explore the composition, molecular weight and monosaccharide composition of ,Flammulina velutipes polysaccharides by DEAE Cellulose-52, High Performance Gel Filtration Chromatography (HPGFC) and HPLC with PMP derivative with the FVP isolated and purified from Flammulina velutipes. The results showed that Flammulina velutipes polysaccharides were composed of three kinds of polysaccharides; the molecular weight of FVP was composed of 4191338, 372779, 19002; the molecular weight of 372779, 19002, one of the biggest average molecular weight polysaccharides is neutral polysaccharide, the rest of the two kinds of polysaccharide composition of less average molecular weight is acidic polysaccharides and the proportion of two kind of acidic polysaccharides significantly greater than neutral polysaccharide, 44.31 and 37.76% respectively, only 17.93% of neutral polysaccharide. FVP was composed of Glc, Man, Gal, Xyl, Fuc; the highest content of Glc, followed by Gal and Man, Xyl and Fuc content is relatively low. The molar ratio was relatively 13.05:2.75:3.16:1.48:1.00. In conclusion, FVP contained the more Glc, the less Fuc and a small amount of galacturonic acid and glucuronic acid, which showed FVP may contain acidic polysaccharides.

Difference in structure and complement fixing activity of pectic polysaccharides from different plant parts of Echinacea purpurea (L.) Moench.

Water soluble pectic polysaccharide fractions were isolated from different parts of Echinacea purpurea in order to elucidate any structural and biological differences. Water extracts of stems, leaves, flower buds, open flowerheads, post fertile flowers and roots were purified by ion exchange chromatography and by gelfiltration. The polysaccharides consisted of a high amount of galacturonic acid, but also rhamnose, arabinose and galactose with glycosidic linkages compatible with rhamnogalacturonan type I (RG-I), arabinogalactan I (AG-I) and arabinogalactan II (AG-II) structures. Precipitation with Yariv-reagent supports the presence of AG-II. The polysaccharides isolated from the different plant part showed largely the same structure, but with some differences mainly in the arabinan component. The complement fixing activity varied considerable between the plant parts. The structural elucidation indicated that the glycosidic linkages to arabinose are important for the complement fixating activity, and thus a diminished activity after weak hydrolysis of the pectic fractions was observed. Key words: Complement fixing activity, Echinacea, glycosidic linkages, pectic polysaccharides, Yariv-reagent.

Extraction of valuable compounds from the flavedo of Citrus junos using subcritical water

Pectin contained in the flavedo of citrus fruits was sequentially extracted with water, a chelating agent, and hydrochloric acid. The amount of pectin obtained was quantified as the amount of galacturonic acid according to the dimethylphenol method and found to be 21%. Next, pectin was separated from the flavedo of Citrus junos with hot compressed water (HCW) using a semi-continuous flow reactor. HCW was continuously delivered into the reactor while gradually increasing the temperature from 60 to 160 °C at 20 MPa with flow rates of 2.1, 3.5, and 7.0 mL/min. The extract from the reactor was cooled and 7-mL fractions were collected. From the analysis of each fraction, it was found that pectin was rapidly extracted when the temperature of the reactor reached 160 °C. Yield of the pectin reached as high as 80%. From cation analysis, a large amount of potassium was detected in the leading extraction peak.

Characterization of the Immunologically Active Components of Glycyrrhiza uralensis Prepared as Herbal Kimchi

초록·키워드 목차 오류제보하기 A crude polysaccharide fraction (GU-3) from the roots of Glycyrrhiza uralensis (licorice root), a screened herbal plant used in the preparation of herbal kimchi, enhanced Peyer's patch mediated bone marrow cell proliferation and NK cell-mediated tumor cytotoxicity against Yac-1 cells. GU-3 was further purified by DEAESepharose CL-6B yielding fractions designated as GU-3I, and 3IIa～3IIe. GU-3IIa is mainly composed of arabinose, galactose and galacturonic acid, and showed the highest bone marrow cell proliferation activity. In addition, GU-3IIb had arabinose, galactose, rhamnose and galacturonic acid as the component sugars with a small quantity of protein; GU-3IIb also enhanced activity of NK cell-mediated tumor cytotoxicity. After these fractions were further fractionated via gel filtration on Sepharose CL-6B or Sephacryl S-300, two immunological active polysaccharides, GU-3IIa-2 and 3IIb-1 were purified from the respective fractions. GU- 3IIa-2 mostly contained neutral sugars (75%) such as arabinose and galactose (molar ratio; 1.0 : 0.7) in addition to a considerable amount of galacturonic acid (20%), whereas GU-3IIb-1 was composed of arabinose, galactose, rhamnose and galacturonic acid (molar ratio; 0.3 : 0.5 : 0.1 : 1.0). Methylation analysis indicated that GU-3IIa-2 was composed mainly of terminal, 4- or 5-linked and 3,4- or 3,5-branched arabinose, 3-linked, 4-linked and 3,6-branched galactose, and terminal and 4-linked galacturonic acid whereas GU-3IIb-1 contained various glycosidic linkages such as terminal and 4- or 5-linked arabinose, 2,4-branched rhamnose, terminal and 4-linked galactose, and terminal and 4-galacturonic acid. Single radial gel diffusion indicated that only GU-3IIa-2 strongly reacted with β-D-glucosyl-Yariv antigen. These results suggest that bone marrow cell proliferating activity and enhancement of NK cell-mediated tumor cytotoxicity of GU-3 are caused by polysaccharides containing a pectic arabinogalactan (GU-3IIa-2) and pectic polysaccharide (GU-3IIb-1). AbstractINTRODUCTIONMATERIALS AND METHODSRESULTS AND DISCUSSIONACKNOWLEDGEMENTSREFERENCES

Influence of molybdenum on the accumulation and composition of the water-soluble polysaccharides of Plantago psyllium

The authors have studied the dynamics of the accumulation of polysaccharides in flaxseed plantain when it is given a foliar top dressing with molybdenum, and also their monosaccaride composition and physicochemical properties. The amounts of galacturonic acid were determined by potentiometric titration. The results of the investigations permit the conclusions that molybdenum somewhat decreases the amounts of total monosaccaride complex and of galacturonic acid while considerably raising the amount of -OCH/sub 3/.

Composition of capsular polysaccharides of smooth and rough types of colonies of azotobacter chroococcum

Capsular polysaccharides of smooth and rough types of colonies of different strains ofAzotobacter chroococcum were analyzed. In polysaccharide hydrolysates the following compounds were detected: galacturonie acid, glucosamine, galactose, glucose, arabinose, fructose, xylose, ribose, rhamnose, deoxy-ribose and another unidentified deoxy-sugar. The smooth types of colonies differ from the rough ones in containing different amounts of galacturonic acid and of galactose in their polysaccharide. In the smooth type there is more galacturonic, acid, in the rough ones there is more galactose.

Oxidation Products of Leuco-anthocyanins as Inhibitors of Fungal Polygalacturonase in Rotting Apple Fruit

Sclerotinia fructigena Aderh. and Ruhl. causes a firm, brown rot of apple fruit. When the fungus is grown in a synthetic medium, active polygalacturonase and pectin-methylesterase can be detected in the culture filtrate. However, examination of Bramley's Seedling apples rotted by the fungus revealed that although the total pectic substances of the tissue insoluble in water had been reduced by 10 per cent and a small amount of galacturonic acid formed, only a trace of polygalacturonase activity could be detected; pectin-methylesterase activity was found. An explanation for the absence of polygalacturonase activity in rotted tissue was sought.