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PubMed1992

Acceptor requirements for GDP-fucose:xyloglucan 1,2-alpha-L-fucosyltransferase activity solubilized from pea epicotyl membranes.

GDP-fucose:xyloglucan (XG) fucosyltransferase from growing Pisum epicotyl tissue was solubilized in detergent and used to examine the capacity of intact XG from Tamarindus seeds, and its partial hydrolysis products, to act as fucose acceptors with GDP-[14C]fucose as donor. Native seed XG (Mr greater than 10(6) Da) was partially depolymerized by incubation with Trichoderma cellulase for various periods of time. Cellulase was inactivated and reaction mixtures were incubated with GDP-[14C]fucose plus solubilized pea fucosyltransferase and then fractionated on columns of Sepharose CL-6B or Bio-Gel P4. Specific activities (Bq/microgram carbohydrate) of fragments with Mr ranging from 10(6) to 10(4) Da were constant throughout the size ranges, indicating that all stretches of the XG chains were available for fucosylation. More complete cellulase hydrolysis yielded subunit oligosaccharides that chromatographed in a cluster of hepta-, octa-, and nonasaccharides, none of which acted as fucosyl acceptors when incubated with pea fucosyltransferase. However, a substantial amount (up to half of hydrolysate) of larger transient oligosaccharides was also formed with a size equivalent to three of the oligosaccharide subunits. Octasaccharide subunits in this trimer were readily fucosylated. This fucosyltransfer was inhibited by uncombined (free) subunit oligosaccharides, which implies that the latter could bind to the transferase and displace at least part of the trimer, even though they could not themselves be fucosylated. Reduction of the trimer oligosaccharide with NaB3H4, followed by further hydrolysis with cellulase, resulted in tritiated nonasaccharide and unlabeled octasaccharide in a concentration ratio of 1:2. The tamarind XG trimer which accepts fucose is therefore composed mainly of the subunit sequence: octa-octa-nonasaccharide (reducing). One of the terminal oligosaccharide subunits in this trimer, probably the nonasaccharide, appears to be required as a recognition (binding) site in fucosyltransferase in order for adjacent octasaccharide(s) to be fucosylated by the active (catalytic) enzyme site.

Cell Membrane↗
PubMed1994

Precursors of N-nitroso compounds in some Nigerian medicinal plants.

Twenty-seven tropical plants of medicinal importance were analysed for primary and secondary amines by chemiluminescence detection on a Thermal Energy Analyzer (TEA) modified for use on 'nitrogen mode' following derivatization with benzene sulphonyl chloride (BSC) and gas chromatographic (GC) separation of their sulphonamides. Nitrite was determined by colorimetry at 540 nm after diazotization with sulphanilamide and coupling with N-(1-naphthyl)ethylenediamine to form an azo dye. Nitrate was determined as nitrite following on-line reduction by granulated cadmium. Dimethylamine in the range of 0.5 ppm to 18.2 ppm was detected in 96% of samples, while pyrrolidine ranged between 0.7 ppm and 12.78 ppm in 14 samples. Isobutylamine, methylamine and ethylamine were the most ubiquitous primary amines. Largest number of secondary amines (four) was found in Azadirachta indica (Neem) while largest number of primary amines (six) was detected in Azadirachta indica and Tamarindus indica (Tsamiya) which also contained the highest amount of total primary amines (148.8 ppm). Nitrate and nitrite were seldom found in plant extracts whose pH were generally below 7.0. These findings suggests that early exposures to precursors of N-nitroso compounds via medicinal plants might contribute to total risk posed by environmental carcinogens in Nigeria.

Amines↗
PubMed2005

Antibacterial properties of tropical plants from Puerto Rico.

In an effort to document the antibacterial properties of plants commonly used by the people of Puerto Rico, we studied the effects of 172 plant species, utilizing the disc diffusion method, against Escherichia coli and Staphylococcus aureus. The methanolic extracts of 14 species showed antibacterial activities during this preliminary screen. These positive plant extracts were tested successively over 15 additional species. The results showed that extracts from Citrus aurantifolia (Rutaceae), Citrus aurantium (Rutaceae), Punica granatum (Punicaceae), Phyllanthus acidus (Euphorbiaceae) and Tamarindus indica (Caesalpiniaceae) possess strong in vitro antibacterial activity against the bacteria tested.

Anti-Bacterial Agents↗
PubMed1976

[Complete structure of three galactoxyloglucans (amyloids) from seeds].

D-Galacto-D-xylo-D-glucans (amyloids) from Balsamina, Tropaeolum, and Tamarindus seeds behave in a similar manner in the presence of various glycosidase preparations: slow depolymerization by enzymes from several germinated or non-germinated seeds, and hydrolysis into monosaccharides and oligosaccharides by commercial cellulase and hemicellulase preparations from fungi. A purified cellulase from Penicillium notatum gave a dialyzable fraction almost exclusively composed of alpha-D-xylopyranosyl-(1 leads to 6)-D-glucose residues and a nondialyzable fraction composed of chains of beta-D-(1 leads to 4) [With some (1 leads to 3)]-glucopyranosyl residues; beta-D-galactopyranosyl-(1 leads to 2)-alpha-D-xylosyl groups are linked to some of the beta-D-glucosyl residues at O-6. The presence of (1 leads to 3)-linkages in the D-glucan chain of the Balsamina was verified by methylation and sequential periodate oxidation-borohydride reduction; the distribution of the substituents on the D-glucan chain is not regular. The main D-glucan backbone, where the beta-D-glucosyl residues are partly linked at O-6 to beta-D-galactosyl-(1 leads to 2)-D-xylosyl groups, is linked to D-glucan chains where almost all the D-glucose units are linked at O-6 by one alpha-D-xylosyl group. The presence of 3,6-di-O-methyl-D-glucose after permethylation and hydrolysis suggests that the xyloglucan chains are linked to O-2 of the D-glucosyl units of the galactoxyloglucan backbone.

Amyloid↗
PubMed1997

A new family of oligosaccharides from the xyloglucan of Hymenaea courbaril L. (Leguminosae) cotyledons.

The xyloglucan from cotyledons of Hymenaea courbaril was hydrolysed with endo-(1,4)-beta-D-glucanase (cellulase) and analysed by TLC and HPAEC. The limit digest was different from those obtained from xyloglucans of Tamarindus indica and Copaifera langsdorffii. On treatment with nasturtium beta-galactosidase, two main oligosaccharides were detected by TLC and HPAEC. Using a process of enzymatic sequencing involving alternate treatments with a pure xyloglucan oligosaccharide-specific alpha-xylosidase, and a pure beta-glucosidase, both from nasturtium, their structures were deduced to be XXXG and a new oligosaccharide XXXXG. These structures were confirmed by 1H NMR. The relative proportions of XXXG and XXXXG indicate that approximately half of the subunits in Hymenaea xyloglucan are based on the new oligosaccharides. In the native polymer the XXXXG subunits are likely to carry galactosyl substituents in varying proportions, since cellulase hydrolysates contained many bands which were converted to XXXXG on hydrolysis with nasturtium beta-galactosidase. Although no comparative studies on the physico-chemical properties of Hymenaea courbaril xyloglucan have yet been performed, our results indicate that this polymer is less interactive with iodine when compared with T. indica and C. langsdorffii xyloglucans, suggesting that changes in conformation may occur due to the presence of XXXXG.

Chromatography, Thin Layer↗
PubMedDate not supplied

Lectins in fruits having gastrointestinal activity: their participation in the hemagglutinating property of Escherichia coli O157:H7.

BACKGROUND: In fruits with therapeutic properties for antidiarrheal and laxative uses, the presence of lectins may be the bioactive properties that interfere with bacterial adhesion, thought to be competition for glycoside signal sites in the attachment. METHODS: This study identifies lectins in crude extracts from fruits such as Tamarindus indica (tamarind), Spontia vulgaris (plum), Psidium guava (guava), Mangifera indica (mango), Cydonia vulgaris (quince), and Crataegus mexicanus (tejocote). To verify the procedures, extracts from Ricinus communis (castor bean), Glycine max (soybean), Phaseolus vulgaris (beans), Vicia fava (fava bean), and Solanum tuberosum (potato) were used as controls for lectin activity. Both sources of lectins were analyzed to determine their participation in the host-parasite interaction, using as a model the hemagglutinating properties of Escherichia coli O157:H7 (EHA). RESULTS: All extracts showed hemagglutination to group O erythrocytes test (HA) with the exception of mango. Two new galactose-specific lectins were identified from tamarind and guava. When analyzed for participation in EHA, only guava lectins inhibited this, while soybean lectin induced hemolysis; as both lectins bind to galactose, it is probable that their recognition occurs in different domains. Sugars involved in the attachment between Escherichia coli O157:H7 and red cells were identified and again, galactose in addition to mannose was found to be related in EHA. On the other hand, guava lectins also agglutinated E. coli O157:H7, perhaps due to the same galactose-specific lectin or to another type of lectin. CONCLUSIONS: In summary, guava has a galactose-specific lectin that prevents adhesion of E. coli O157:H7 to red cells; this lectin is mediated by galactose. Prevention could also be due to their capacity of agglutinating E. coli by guava lectins. Soybean lectin induced hemolysis only when bacteria was present, but not with floating secretions. This finding showed that guava is a source of lectin that can be explored to prevent adhesion of E. coli to epithelial intestinal cells; contrariwise, soya must be studied to see its participation in the uremia caused during E. coli O157:H7 pathogenesis.

Bacterial Adhesion↗
PubMed2002

Indigenous knowledge system for treatment of trypanosomiasis in Kaduna state of Nigeria.

A survey was carried out in Kaduna State of Nigeria to establish the indigenous knowledge system for treating trypanosomiasis in domestic animals. Questionnaire and interviews were, respectively, administered to, or conducted with about 200 livestock farmers and traders spread around the state. Data obtained revealed the use of several plants either alone or in combination, for the treatment and management of trypasonomiasis. The most common plants encountered were Adansonia digitata, Terminalia avicennoides, Khaya senegalensis, Cissus populnea, Tamarindus indica, Lawsonia inermis, Boswellia dalzielli, Pseudocedrela kotschi, Syzyium quinensis, Sterculia setigera, Afzelia africana, Prosopis africana, Lancea kerstingii. The method of preparation and mode of administration of some of these plants in the treatment of trypanosomiasis are reviewed and discussed.

Animals↗
PubMed2003

Screening of antimutagenicity via antioxidant activity in Cuban medicinal plants.

The reducing activity on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, z.rad;OH radical scavenging potential, in vitro inhibition of lipid peroxidation and modulation of mutagenicity induced by ter-butyl hydroperoxide (TBH) in Escherichia coli were sequentially screened in 45 species of plants used with medicinal purposes in Cuba, in a search for antioxidant agents which protect DNA against oxidative stress.Five species, e.g. Tamarindus indica L., Lippia alba L., Pimenta dioica (L.) Merr, Rheedia aristata Griseb. and Curcuma longa L. displayed IC(50)<30 micro g/ml in the DPPH radical reduction assay and IC(50)<32 micro g/ml in lipid peroxidation inhibition testing. Pimenta dioica and Curcuma longa L. showed also a 20% inhibition of the in vitro induced z.rad;OH attack to deoxyglucose. Further antimutagenesis assay in Escherichia coli IC 188 evidenced that only Pimenta dioica prevents DNA damage by TBH to the test bacteria. A role of antioxidant enzymes is presumed in this case, as judged by a different response in the isogenic Escherichia coli IC 203 deficient in catalase and alkyl hydroperoxide reductase and the discrete inhibition of oxidative mutagenesis also observed when pre-treatment of the extract was assayed. Eugenol, the main constituent of the essential oil of Pimenta dioica, also inhibited oxidative mutagenesis by TBH in Escherichia coli, at concentrations ranging from 150 to 400 micro g/plate.

Antimutagenic Agents↗
PubMed1998

Jamu Gendong, a kind of traditional medicine in Indonesia: the microbial contamination of its raw materials and endproduct.

An examination on the microbiological quality of seven kinds of Jamu Gendong (JG) and their raw materials has been conducted according to the requirements of microbial contamination in traditional medicine, issued by the Department of Health of Indonesia in 1986. Samples of JG and their raw materials were taken from producers in three districts of Surabaya. The samples were subject to the following examinations: total plate count (TPC), MPN coliform, the enumeration of molds and yeasts, the presence or absence of Staphylococcus aureus, Salmonella and Vibrio. Each time the JG samples were taken from different producers together with their raw materials. The results of this investigation showed that most of the JG samples were heavily contaminated with bacteria, yeasts and molds. For bacteria, taken from the TPC results, their numbers were ranging from 7.7 x 10(2) microorganisms/ml to too many to count (TMTC). For yeasts and molds the numbers showed variations from 0 microorganisms/ml to TMTC. Contamination with Coliform in 1 ml of JG were ranged from 0 to > 2.4 x 10(6) microorganisms. In most of the samples pathogenic Staphylococci, Salmonella sp. and Vibrio sp. were not detected, so that a conclusion can be drawn that most of the contamination in JG are saprophytic, only a few pathogenic. The results also show that it is possible to have JG which fulfill the government's requirements. Similar results were obtained with the plant material constituents of JG such as rhizomes, leaves, herbs and fruits of Piper nigrum and Piper retrofractum, with the exception of Piper betle leaves and P. retrofractum fruits, both showing low contamination of Coliform bacteria. However, the fruits of Citrus aurantifolia and Morinda citrifolia were less contaminated, just like seeds of Oryza sativa, Parkia roxburghii, bulbs of Allium sativum and the pulp of Tamarindus indica. With these plant constituents of JG, it might be of interest to screen their antibacterial and antifungal activities.

Bacteria↗
PubMed2006

Screening of tropical fruit volatile compounds using solid-phase microextraction (SPME) fibers and internally cooled SPME fiber.

In this study, the optimization and comparison of an internally cooled fiber [cold fiber with polydimethylsiloxane (PDMS) loading] and several commercial solid-phase microextraction (SPME) fibers for the extraction of volatile compounds from tropical fruits were performed. Automated headspace solid-phase microextraction (HS-SPME) using commercial fibers and an internally cooled SPME fiber device coupled to gas chromatography-mass spectrometry (GC-MS) was used to identify the volatile compounds of five tropical fruits. Pulps of yellow passion fruit (Passiflora edulis), cashew (Anacardium occidentale), tamarind (Tamarindus indica L.), acerola (Malphigia glabra L.), and guava (Psidium guajava L.) were sampled. The extraction conditions were optimized using two experimental designs (full factorial design and Doehlert matrix) to analyze the main and secondary effects. The volatile compounds tentatively identified included alcohols, esters, carbonyl compounds, and terpernes. It was found that the cold fiber was the most appropriate fiber for the purpose of extracting volatile compounds from the five fruit pulps studied.

Alcohols↗
PubMed2001

Decaying wood in tree trunk hollows as a natural substrate for Cryptococcus neoformans and other yeast-like fungi of clinical interest.

The occurrence of Cryptococcus neoformans var. neoformans and other yeast-like fungi of clinical interest in decaying wood inside tree trunk hollows, bark and other plant materials is reported. The var. neoformans was isolated from 3 of 45 (6.6%) wood and one of 390 Eucalyptus bark samples. Two of the positive wood samples came from a tree trunk hollow of Butea monosperma (Family: Papilionaceae) growing in Roshan Ara Garden, Old Delhi whereas the third was from a trunk hollow of Tamarindus indica (Family: Papilionaceae) growing outside of Talkatora Garden, New Delhi. The solitary positive Eucalyptus bark sample originated from Amritsar. The isolations of var. neoformans from decaying wood inside trunk hollows of B. monosperma and T indica constitute the first record of the natural occurrence of this pathogen in association with these trees. The observation reinforces the recent evidence for decaying wood inside trunk hollows of some trees to be a new natural habitat of the variety neoformans. Besides, in consonance with their essentially saprobic character, a number of other yeast-like fungi were sporadically isolated. This includes, Cryptoccus laurentii, Cryptococcus albidus, Candida lusitaniae, C. guilliermondii, C. krusei, C. tropicalis, C. zeylanoides, Trichosporon cutaneum, Rhodotorula mucilaginosa, R. glutinis, Geotrichum capitatum, G. klebahnii and Sporobolomyces salmonicolor. Cryptococcus neoformans var. gattii was not found in any of the 702 samples of plant materials, including the bark and detritus of Eucalyptus camaldulensis and E. tereticornis trees. A more extensive environmental survey, covering divergent climatic regions, is warranted to identify the natural reservoirs of var. gattii in India.

Cryptococcus neoformans↗
PubMed2001

Ten isoenzymes of xyloglucan endotransglycosylase from plant cell walls select and cleave the donor substrate stochastically.

To map the preferred cleavage sites of xyloglucan endotransglycosylases (XETs; EC 2.4.1.207) along the donor substrate chain, we incubated the enzymes with tamarind (Tamarindus indica) xyloglucan (donor substrate; approximately 205 kDa; 21 microM) plus the nonasaccharide [(3)H]XLLGol (Gal(2).Xyl(3).Glc(3). [(3)H]glucitol; acceptor substrate; 0.6 microM). After short incubation times, to minimize multiple cleavages, the size of the (3)H-labelled transglycosylation products (determined by gel-permeation chromatography) indicated the positions of the cleavage sites relative to the non-reducing terminus of the donor. There was very little difference between the size profiles of the products formed by any of ten XETs tested [one native XET purified from cauliflower (Brassica oleracea) florets, four native XET isoenzymes purified from etiolated mung-bean (Phaseolus aureus) shoots, native XETs purified from lentil (Lens culinaris) and nasturtium (Tropaeolum majus) seeds, and three insect-cell-produced thale-cress (Arabidopsis thaliana) XETs (EXGT, TCH4 and MERI-5)]. All such product profiles showed a good fit to a model in which the enzyme chooses its donor substrate independently of size and attacks it, once only, at a randomly selected cleavage site. The results therefore do not support the hypothesis that different XET isoenzymes are adapted to produce longer or shorter products such as might favour either the efficient integration of new xyloglucan into the cell wall or the re-structuring of old xyloglucan within an expanding wall.

Cell Wall↗
PubMed2000

Energy and micronutrient composition of dietary and medicinal wild plants consumed during drought. Study of rural Fulani, northeastern Nigeria.

Two rural settled Fulani villages, northeastern Nigeria, were surveyed for dietary practices and use of edible wild plants (n = 100 households). Commonly consumed species of edible wild barks, fruits, leaves, nuts, seeds, and tubers were analyzed for protein, fat, and carbohydrate and for minerals. Kuka bark (Adansonia digitata) given to infants to increase weight gain was high in fat, calcium, copper, iron, and zinc. Cediya (Ficus thonningii), dorowa (Parkia biglobosa) and zogale (Moringa oleifera) were good sources of protein and fat and excellent sources of calcium and iron or copper and zinc. Fruits, leaves, and nuts of aduwa (Balanites aegyptiaca) were widely used during the dry season and during drought. Edible wild species available during the wet season generally were inferior in energy and micronutrient mineral content compared to dry season plants. Fruits commonly eaten by children were poor sources of protein and minerals but rich in carbohydrate and fiber. Tsamiya seeds (Tamarindus indica) were good sources of zinc and used to make dawwa (porridge) commonly consumed during pregnancy. Kirya seeds (Prosopos africana) contained the highest zinc concentrations. Shiwaka leaves (Veronia colorate) consumed by pregnant women to increase breastmilk production and to expel intestinal worms, were high in fiber, phosphorus, magnesium, manganese, and were adequate sources of calcium.

Diet↗
PubMed1999

A new cardenolide uzarigenen-3-O-beta-D-xylopyranosyl (1-->2)-alpha-L-rhamnopyranoside.

A new cardenolide C34H52O12, m.p. 225-226 degrees C, [M+ -H] 651 (EIMS) was isolated from the acetone soluble fraction of the concentrated 90% ethanolic extracts of the seeds of Tamarindus indica (Linn.). It was identified as uzarigenin-3-O-beta-D-xylopyranosyl (1 -->2)- alpha-L-rhamnopyranoside (I) by different colour reactions, chemical degradations and spectral analysis.

Cardenolides↗
PubMed1994

Significant reduction in chloroquine bioavailability following coadministration with the Sudanese beverages Aradaib, Karkadi and Lemon.

Chloroquine bioavailability in healthy males was examined following oral coadministration of 600 mg with three common Sudanese beverages, Aradaib (Tamarindus indica), Karkadi (Hibiscus sabdarifa) and Lemon (Citrus limetta) and drinking water. The tablets and beverages were taken on an empty stomach after an overnight fast. The plasma chloroquine concentrations were measured by HPLC. The extent and rate of chloroquine bioavailability were described by the area under the plasma concentrations versus time curve (AUC), the peak plasma concentration (Cmax) and with the time to reach Cmax (Tmax), respectively. The mean (+/- S.E.) AUC values after administration with water (control) and Aradaib, Karkadi and Lemon, respectively, were 7.52 +/- 0.87, 2.60 +/- 0.24, 2.16 +/- 0.30 and 2.41 +/- 0.29 mg.h/L. The corresponding mean Cmax values were 553 +/- 17.8, 184 +/- 21.3, 148 +/- 14.1 and 210 +/- 17.4 mg/L and the corresponding Tmax values were 3.0 +/- 1.0, 3.2 +/- 1.2, 2.6 +/- 0.8 and 2.5 +/- 1.0 h. The results indicate a statistically significant reduction in the AUC and Cmax of chloroquine as a result of a coadministration with each of the three beverages. A parallel reduction in the drugs antimalarial efficacy might be expected.

Adult↗
PubMed2005

Evaluation of photo-mutagenicity and photo-cytotoxicity of food coloring agents.

Pigments extracted from natural products are widely used for food coloration in Japan. An investigation concerning the photo-mutagenicity and photo-carcinogenicity of frequently used colorants in Japan was performed. Colorants examined were from Laccifer lacca (lac-color), Coccus cacti (cochineal-color), Carthamus tinctorius (carthamus yellow), Gardenia augusta (gardenia yellow and gardenia blue), Monascus anka and Monascus purpureus (monascus red), the skin of Vitis vinifera and Vitis labrusca (grape-skin color), Tamarindus indica (tamarind brown) and Beta vulgaris (beet red). No significant increase in bacterial mutation was found when Salmonella typhimurium TA98, TA100 and TA102 were simultaneously treated with colorants and subjected to UVA irradiation for 30 min. When colorant solutions were subjected to UVA irradiation for 4 h, irradiated solutions containing lac-color became slightly mutagenic toward S.typhimurium TA98 without metabolic activation. A decrease in cell survival resulted when WTK-1 cells were subjected to UVA irradiation for 60 min in the presence of purpurin at 1 mg/ml. Delayed cytotoxicity was also observed following 24 h incubation in fresh medium of samples that were subjected to UVA irradiation for 60 min in the presence of colorant (carthamus yellow, grape-skin color, gardenia blue, cochineal-color, monascus red or purpurin).

Carcinogens↗
PubMed1996

Fine substrate specificities of four exo-type cellulases produced by Aspergillus niger, Trichoderma reesei, and Irpex lacteus on (1-->3), (1-->4)-beta-D-glucans and xyloglucan.

To investigate the fine substrate specificities of four highly purified exo-type cellulases (Exo-A from Aspergillus niger, CBHI and CBHII from Trichoderma reesei, and Ex-1 from Irpex lacteus), water-soluble substrates such as barley glucan, xyloglucan from tamarind (Tamarindus indica L.), and their oligosaccharides were employed. Four exo-type cellulases immediately hydrolyzed 3-O-beta-D-cellotriosylglucose to produce cellobiose and laminaribiose. In contrast, CBHII showed no hydrolytic activity towards 3(2)-O-beta-D-cello-biosylcellobiose, which was hydrolyzed to cellobiose by the other exo-type cellulases. These cellulases hydrolyzed the internal linkages of barley glucan and lichenan in an endo-type fashion to produce cellobiose and mix-linked oligosaccharides as main products. The DP-lowering activities of the four exo-type cellulases on barley glucan were in the order of Ex-1, CBHII, Exo-A, and CBHI. Based on gel permeation chromatography analysis of the hydrolysates, Ex-1 seemed to attack the internal cellobiosyl unit adjacent to beta-1,3-glucosidic linkages in barley glucan molecule more frequently than did the other cellulases. Xyloglucan was hydrolyzed only by CBHI and CBHII, and produced hepta-, octa-, and nona-saccharides. In addition, a xyloglucan tetradecasaccharide (XG14) was split only to heptasaccharide (XG7) by CBHI and CBHII.

Aspergillus niger↗
PubMed1997

Xyloglucan galactosyl- and fucosyltransferase activities from pea epicotyl microsomes.

Microsomal membranes from growing tissue of pea (Pisum sativum L.) epicotyls were incubated with the substrate UDP-[14C]galactose (Gal) with or without tamarind seed xyloglucan (XG) as a potential galactosyl acceptor. Added tamarind seed XG enhanced incorporation of [14C]Gal into high-molecular-weight products (eluted from columns of Sepharose CL-6B in the void volume) that were trichloroacetic acid-soluble but insoluble in 67% ethanol. These products were hydrolyzed by cellulase to fragments comparable in size to XG subunit oligosaccharides. XG-dependent galactosyltransferase activity could be solubilized, along with XG fucosyltransferase, by the detergent 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate. When this enzyme was incubated with tamarind (Tamarindus indica L.) seed XG or nasturtium (Tropaeolum majus L.) seed XG that had been partially degalactosylated with an XG-specific beta-galactosidase, the rates of Gal transfer increased and fucose transfer decreased compared with controls with native XG. The reaction products were hydrolyzed by cellulase to 14C fragments that were analyzed by gel-filtration and high-performance liquid chromatography fractionation with pulsed amperometric detection. The major components were XG subunits, namely one of the two possible monogalactosyl octasaccharides (-XXLG-) and digalactosyl nonasaccharide (-XLLG-), whether the predominant octasaccharide in the acceptor was XXLG (as in tamarind seed XG) or XLXG (as in nasturtium seed XG). It is concluded that the first xylosylglucose from the reducing end of the subunits was the Gal acceptor locus preferred by the solubilized pea transferase. These observations are incorporated into a model for the biosynthesis of cell wall XGs.

Carbohydrate Sequence↗