The 3-aminopropyl glycoside of a heptasaccharide fragment of the cell wall mannan from Candida guilliermondii18, which corresponds to the antigenic Factor 9, has been synthesized by a convergent approach based on glycosylation of a tetrasaccharide acceptor with a trisaccharide donor as the key step to give a protected heptasaccharide 17. Subsequent two-step deprotection of 17 afforded the heptamannoside 18, which was then conjugated with BSA using the squarate procedure. 相似文献
The technique of rocket affinoelectrophoresis, initially introduced for the quantitation of a succinylated mannan by concanavalin A [Owen, P., and Salton, M. R. J. (1976) Anal. Biochem.73, 20–26] has been extended to (a) the quantitation of four other macromolecules: vz. streptococcal lipoteichoic acid, I blood group substance, desialylated bovine submaxillary mucin, and desialylated pig submaxillary mucin; and (b) the use of three other lectins: vz. wheat germ agglutinin, soybean agglutinin and peanut agglutinin. In all cases stable-affinity precipitin rockets were observed the heights of which bore an approximately linear relationships to the amount of sample analyzed. For all lectins, the detection limits were in the range of 15–25 ng. Furthermore, a new technique has been introduced called crossed affinoelectrophoresis which is basically a two-dimensional variant of rocket affinoelectrophoresis. This technique can be used with concanavalin A, wheat germ agglutinin, soybean agglutinin, or peanut agglutinin in the affinity gel and allows the examination of glycoprotein homogeneity. Modification of this technique, involving the use of other lectins or antiserum in intermediate gels, is also described and evaluated. 相似文献
Anti-mannan was produced in rabbits after peptidoglucomannan in adjuvant was injected. The antiserum was used to detect mannan by immunodiffusion and counterimmunoelectrophoresis (CIE) in gel and by sandwich enzyme-linked immunosorbent assay (ELISA). The antiserum detected lower concentrations of mannan of serotype A than of serotype B. Except in CIE, the reactions were more pronounced at 4°C than at higher temperatures. CIE detected 0.8 g/ml mannan A or 12.5 /ml mannan B. Sandwich ELISA detected 3 ng/ml mannan A or 105 ng/ml mannan B. Mannan was not detected in the serum of patients or rabbits with candidiasis.Use of trade names is for identification only and does not constitute endorsement by the Public Health Service or by the U.S. Department of Health, Education and Welfare. 相似文献
Specific rabbit antisera against purified Hordeum vulgare seedling RNase I from two winter barley cultivars each formed a single precipitin band when reacted with the homologous crude tissue extract. RNase antigen from either cultivar was equally reactive with both antisera when evaluated by immunodiffusion and immunoelectrophoresis. A small but consistent difference in anti-RNase specificity between cultivars was shown by passive hemagglutination inhibition, suggesting that molecular differences may exist between the two RNase antigens. Immunodiffusion and rocket immunoelectrophoresis were used to qualitatively test the cross-reactivity of protein preparations from various members of the genus Hordeum and species from other related grass genera. Neither antiserum showed cross-reactivity with soluble protein preparation from species outside the genus Hordeum. A few species within the genus Hordeum were cross-reactive. A modification of rocket immunoelectrophoresis was developed to determine the amount of RNase in unpurified tissue extracts. The technique involved a template-reservoir which allowed detection of 250 ng RNase in tissue extract volumes of 50 μl. The amount of RNase in unpurified protein extracts from the two cultivars of barley was similar. 相似文献
With the intent of contributing to a carbohydrate-based vaccine against the gastroduodenal pathogen, Helicobacter pylori, we report here the structure of cell-surface mannans obtained from a virulent strain. Unlike other wild-type strains, this strain was found to express in good quantities this polysaccharide in vitro. Structural analysis revealed a branched mannan formed by a backbone of α-(1→6)-linked mannopyranosyl residues with approximately 80% branching at the O-2 position. The branches were composed of O-2-linked Man residues in both α- and β-configurations:In addition, this strain also expressed cell-surface emblematic H. pylori lipopolysaccharides (LPS) containing partially fucosylated polyLacNAc O-chains. Affinity assays with polymyxin-B and concanavalin A revealed no association between the mannan and the LPS. The described mannans may be implicated in the mediation of host-microbial interactions and immunological modulation. 相似文献
The essential oils and extracts of Mylia taylorii and M. nuda were investigated by gas chromatography, mass spectrometry, NMR spectroscopy and chemical correlations. Beside several known compounds 13 new constituents including three new carbon skeletons could be identified. Four hydrocarbons with a molecular formula of C15H22 (m/z 202) were identified as myli-4(15)-ene (1), aromadendra-1(10),4(15)-diene (19), aromadendra-4,10(14)-diene (20) and aromadendra-4,9-diene (21). Three oxaspiro-compounds were identified as 7-epi-bourbon-3-en-5,11-oxide (22), guai-3,10(14)-dien-5,11-oxide (23) and guai-3,9-dien-5,11-oxide (24). The absolute configuration of myli-4(15)-en-3-one (5) could be established by chemical correlation. Together with α-taylorione (7) the corresponding 6,11-seco-compound taylopyran (25) with a new carbon skeleton was identified which serves as a precursor to taylocyclane (26) and taylofuran (27). Taynudol (28) contains a new carbon skeleton with a cyclobutenyl structure. 相似文献
Marine sponges are ancient and simple multicellular filter-feeding invertebrates attached to solid substrates in benthic habitats and host a variety of fungi both inside and on their surface because of its unique ingestion and digest system. Investigation on marine sponge-associated fungi mainly focused on the small molecular metabolites, yet little attention had been paid to the extracellular polysaccharides. In this study, a homogeneous extracellular polysaccharide AS2-1 was obtained from the fermented broth of the marine sponge endogenous fungus Alternaria sp. SP-32 using ethanol precipitation, anion-exchange, and size-exclusion chromatography. Results of chemical and spectroscopic analyses showed that AS2-1 was composed of mannose, glucose, and galactose with a molar ratio of 1.00:0.67:0.35, and its molecular weight was 27.4 kDa. AS2-1 consists of a mannan core and a galactoglucan chain. The mannan core is composed of (1→6)-α-Manp substituted at C-2 by (1→2)-α-Manp with different degrees of polymerization. The galactoglucan chain consists of (1→6)-α-Glcp residues with (1→6)-β-Galf residues attached to the last glucopyranose residue at C-6. (1→6)-β-Galf residues have additional branches at C-2 consisting of disaccharide units of (1→2)-β-Galf and (1→2)-α-Glcp residues. The glucopyranose residue of the galactoglucan chain is linked to the mannan core. AS2-1 possessed a high antioxidant activity as evaluated by scavenging of 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radicals in vitro. AS2-1 was also evaluated for cytotoxic activity on Hela, HL-60, and K562 cell lines by the MTT and SRB methods. The investigation demonstrated that AS2-1 was a novel extracellular polysaccharide with different characterization from extracellular polysaccharides produced by other marine microorganisms. 相似文献
The synthesis, biological assessment, and molecular modelling of new tacrine analogues 11-22 is described. Compounds 11-22 have been obtained by Friedländer-type reaction of 2-aminopyridine-3-carbonitriles 1-10 with cyclohexanone or 1-benzyl-4-piperidone. The biological evaluation showed that some of these molecules were good AChE inhibitors, in the nanomolar range, and quite selective regarding the inhibition of BuChE, the most potent being 5-amino-2-(dimethylamino)-6,7,8,9-tetrahydrobenzo[1,8-b]-naphthyridine-3-carbonitrile (11) [IC50 (EeAChE: 14 nM); IC50 (eqBuChE: 5.2 ??M]. Kinetic studies on the easily available and potent anticholinesterasic compound 5-amino-2-(methoxy)-6,7,8,9-tetrahydrobenzo[1,8-b]-naphthyridine-3-carbonitrile (16) [IC50 (EeAChE: 64 nM); IC50 (eqBuChE: 9.6 ??M] showed that this compound is a mixed-type inhibitor (Ki = 69.2 nM) of EeAChE. Molecular modelling on inhibitor 16 confirms that this compound, as expected and similarly to tacrine, binds at the catalytic active site of EeAChE. The neuroprotective profile of molecules 11-22 has been investigated in SH-SY5Y neuroblastoma cells stressed with a mixture of oligomycin-A/rotenone. Compound 16 was also able to rescue by 50% cell death induced by okadaic acid in SH-SY5Y cells. From these results we conclude that the neuroprotective profile of these molecules is moderate, the most potent being compounds 12 and 17 which reduced cell death by 29%. Compound 16 does not affect ACh- nor K+-induced calcium signals in bovine chromaffin cells. Consequently, tacrine analogues 11-22 can be considered attractive therapeutic molecules on two key pharmacological targets playing key roles in the progression of Alzheimer, that is, cholinergic dysfunction and oxidative stress, as well as in neuronal cerebrovascular diseases. 相似文献
Particulate preparations from Phaseolus aureus produce a d-mannosyl-lipid when treated with GDP-d-mannose. This lipid complex appears to be an active d-mannose donor, and some investigators have proposed that its role might be an obligatory intermediate in mannan synthesis of higher plants. When the partially purified d-mannosyl-lipids, isotopically labeled in the d-mannose moiety, were treated with particulate enzymes under a variety of conditions, a negligible amount of material was produced that behaved as a polysaccharide. Endogenous, particle-bound d-mannosyl-14C-lipid prepared from P. aureus particles readily transferred d-mannose to GDP to yield GDP-d-mannose and was hydrolyzed to free d-mannose when treated briefly with 0.01 n HCl at 100 C. The d-mannosyl-lipid, therefore, exhibits active d-mannose transfer potential in its endogenous state. When endogenous glycosyl-lipid was incubated in the absence of GDP-d-mannose-14C, little or no polysaccharide was produced. It was, instead, slowly degraded to d-mannose. Addition of several different unlabeled sugar nucleotides had no effect on the results. Our studies to date, therefore, offer no evidence that the mannosyl-lipid is an obligatory precursor of polysaccharide. 相似文献
The use of 1,4-butanediol diglyeidyl ether to couple carbohydrate ligands to Sepharose [Sundberg, L., and Porath, J. (1975) J. Chromatogr. 90, 87; Vretblad, P. (1976) Biochim. Biophys. Acta. 434, 169] has been explored with a number of carbohydrate derivatives, such as amino sugars (N-acetylglucosamine, N-acetylgalactosamine, nonacetylated short oligomers of glucosamine), methyl glycosides (O-methyl-α-mannoside and O-methyl-β-galactoside), di- and oligosaccharides (lactose and stachyose), and polysaccharides (yeast mannan and dextrin). Using model reactions it has been established that all but the reducing sugars are sufficiently stable to withstand the alkaline conditions required for the coupling reaction, and that the primary alcohol at the C6 position of the sugars is the primary site for the coupling reaction. In the case of glucosamine, the amino group is six times more reactive than is the 6-hydroxy group. The following affinity adsorbents have been tested and found useful in the purification of lectins and glycosidases: a yeast mannan adsorbent binds jack bean α-mannosidase (0.15 mg/ml of adsorbent) and concanavalin A (0.5 mg/ml); a dextrin adsorbent binds bovine pancreatic α-amylase (2 mg/ml of adsorbent); a lactose adsorbent binds peanut lectin (5 mg/ml of adsorbent); a (GlcNAc)3–4 adsorbent binds wheat germ lectin (50 mg/ml of adsorbent); and, as previously reported [Vretblad, P. (1976) Biochim. Biophys. Acta. 434, 169], a GlcNAc adsorbent binds wheat germ lectin (10 mg/ml of adsorbent) and a GalNAc adsorbent binds soybean lectin (18 mg/ml of adsorbent). 相似文献
A novel polyhydroxylated C29-sterol, 25ξ-methyl-22-homo-5α-cholest-7,22-diene-3β,6β,9α-triol, designated globosterol (1), together with one known tetrahydroxylated ergosterol (22E, 24R)-ergosta-7,22-diene-3β,5α,6β,9α-tetraol (2) has been isolated from the cultures of an endophytic fungus, Chaetomium globosum ZY-22 originated from the plant Ginkgo biloba. The structures and relative configurations of 1 and 2 were established on the basis of extensive spectroscopic analyses including 1D and 2D NMR (1H-1H COSY, HSQC, HMBC, and NOESY) experiments and comparison with the literature. Globosterol (1) possesses an unprecedented 25-methyl Δ22-C10-side chain and Δ7-3β,6β,9α-hydroxy-steroid nucleus, which represents the first example for C29-steroids of the group. 相似文献
Seven new withanolides (1-7), along with three known ones (8-10), were isolated from the leaves of Withania aristata. Their structures were elucidated on the basis of spectroscopic analysis, including 2D NMR experiments and spectrometric techniques, and the absolute configuration of 1 and 2 was established by CD analysis. In the search for new cytotoxic compounds from Withania species, the isolated compounds 1-9, along with two derivatives, were assayed for their cytotoxicity against HeLa, MCF-7 and A-549 human tumor cell lines. Derivative (4S,20R,22R)-27-acetoxy-4-p-bromobenzoyloxy-1-oxo-witha-2,5,16,24-tetraenolide (13) showed cytotoxicity against all the cell lines assayed with IC50 values ranging from 2.8 to 3.6 μM, and (4S,20R,22R)-4,27-diacetoxy-4-hydroxy-1-oxo-witha-2,5,16,24-tetraenolide (12) exhibited an IC50 value of 5.4 μM on the MCF-7 cell line. 相似文献
Mannan transglycosylases are cell wall enzymes able to transfer part of the mannan polysaccharide backbone to mannan-derived oligosaccharides (Schröder et al. in Planta 219:590–600, 2004). Mannan transglycosylase activity was purified to near homogeneity from ripe tomato fruit. N-terminal sequencing showed that the dominant band seen on SDS-PAGE was identical to LeMAN4a, a hydrolytic endo-β-mannanase found in ripe tomato fruit (Bewley et al. in J Exp Bot 51:529–538, 2000). Recombinant LeMAN4a protein expressed in Escherichia coli exhibited both mannan hydrolase and mannan transglycosylase activity. Western analysis of ripe tomato fruit tissue using an antibody raised against tomato seed endo-β-mannanase revealed four isoforms present after 2D-gel electrophoresis in the pH range 6–11. On separation by preparative liquid isoelectric focussing, these native isoforms exhibited different preferences for transglycosylation and hydrolysis. These results demonstrate that endo-β-mannanase has two activities: it can either hydrolyse mannan polysaccharides, or in the presence of mannan-derived oligosaccharides, carry out a transglycosylation reaction. We therefore propose that endo-β-mannanase should be renamed mannan transglycosylase/hydrolase, in accordance with the nomenclature established for xyloglucan endotransglucosylase/hydrolase. The role of endo-acting mannanases in modifying the structure of plant cell walls during cell expansion, seed germination and fruit ripening may need to be reinterpreted in light of their potential action as transglycosylating or hydrolysing enzymes. 相似文献
Dunalianosides A-I (1-9), esters of arbutin and related phenolic glucosides, were isolated from the buds of Vaccinium dunalianum Wight (Ericaceae) together with 20 known compounds, and their structures were established on the basis of 1- and 2D NMR spectroscopic evidence. Dunalianosides F-H were dimers of p-hydroxyphenyl 6-O-trans-caffeoyl-β-d-glucopyranoside (10). The latter was obtained in extraordinary high yield (22% of dry weight), and dunalianoside I (9) was found to be a conjugate of arbutin with an iridoid glucoside. 相似文献
Leishmanicidal activity of 6α, 7α, 15β, 16β, 24-pentacetoxy-22α-carbometoxy-21β,22β-epoxy-18β−hydroxy-27,30-bisnor-3,4-secofriedela-1,20 (29)-dien-3,4 R-olide (LLD-3 (1)) isolated from Lophanthera lactescens Ducke, a member of the Malpighiaceae, was demonstrated against intramacrophage amastigote forms (IC50 of 0.41 μg/mL). The in vitro leishmanicidal effect of Glucantime, the first choice drug for leishmaniasis treatment, was increased by LLD-3 (1) association. The leishmanicidal effect of LLD-3 (1) was not due to stimulation of nitric oxide production by macrophages. LLD-3 (1) was also not cytotoxic for mouse peritoneal macrophages or B cells as assessed by the XTT and Trypan blue exclusion assays. LLD-3 (1) was unable to affect proliferation of naïve or activated B and T cells, as well as the B cells immunoglobulin synthesis. Cellularity of different tissues, liver and kidney functions were not altered in mice treated with LLD-3 (1), as well as the histology pattern of different organs. Our results add LLD-3 (1) as a potential drug candidate for treatment of leishmaniasis. 相似文献
The polysaccharide secreted by Klebsiella aerogenes type 54 strain A3 was isolated, methylated, the ester carboxyl-reduced, and the product partially hydrolyzed. The resulting, partially O-methylated oligosaccharides were reduced and ethylated, and the mixture of products was fractionated by l.c. The l.c. fractions containing per-O-alkylated oligosaccharide-alditols were analyzed by e.i.-m.s. Pure per-O-alkylated oligosaccharide-alditols were also analyzed by 1H-n.m.r. spectroscopy. The products obtained by base-catalyzed degradation and subsequent ethylation of the per-O-methylated polysaccharide were fractionated by l.c. The main product isolated was analyzed by e.i.-m.s., c.i.-m.s., and 1H-n.m.r. spectroscopy. The results of these studies, in conjunction with results of analytical methods commonly used in the elucidation of polysaccharide structures, unambiguously characterized the primary glycosyl structure of the polysaccharide. Base-labile substituents, previously reported to be present in the polysaccharide, were not studied. Structure 1 revises, and complements, previously reported structures. 相似文献
The extracellular polysaccharides produced as slime or capsule layers by bacterial pathogens of animals and plants have been often implicated as factors essential to pathogenesis. In the present study, virulence of the plant pathogen Erwinia amylovora was correlated with the ability to produce extracellular polysaccharide (EPS). EPS production by a series of field isolates and bacterio-phage-resistant mutants differing in the extent to which they cause symptoms in host tissues was examined by quantitation with a modified Laurell rocket immunoelectrophoresis assay. The amount of EPS produced as an easily removed capsular layer or slime on solid nutrient agar approximated the capacity to exhibit symptoms in host inoculation tests. Features common to the virulent isolates are mucoid colony morphology, sensitivity to EPS-specific bacteriophages [S3 and PEal(h)], and ability to produce a characteristic EPS. Mutants selected for resistance to S3 or nonmucoid colony morphology are deficient in EPS production and have lost the ability to multiply in host tissue and cause symptoms. We conclude that EPS may be directly involved in symptom expression and provide a function essential to the growth of the pathogen in host tissues. 相似文献