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1.
Several studies pointed out soil properties as the prime determinant ofcerrado (the Brazilian savanna) physiognomies, and a gradient from campocerrado (a shrub savanna) to cerradão (a tallwoodland) has been correlated with a soil fertility gradient. Based on thishypothesis, we investigated soil-vegetation relationships in thePé-de-Gigante Reserve (São Paulo State,SoutheasternBrazil). We randomly distributed 10 quadrats (10 × 10 m) oneach ofthe following physiognomies: campo cerrado, cerradosensu stricto, cerradão, andseasonal semideciduous forest, previously defined by the analysis of satelliteimages (LANDSAT-5). We sampled the woody individuals with stem diameter> 3 cm at soil level, identifying their species. In each quadrat, wecollectedsoil samples at the depths of 0–5, 5–25, 40–60, and80–100 cm, and determined pH, K, Ca, Mg, P, Al, H + Al, basesaturation, aluminium saturation, cation exchange capacity, and percentage ofsand, clay and loam. Obtained data were submitted to a canonical correspondenceanalysis (CCA) and to a detrended correspondence analysis (DCA). Our resultsshowed a clear distinction between semideciduous forest and the cerradophysiognomies, based in soil parameters. The former was related to higherconcentrations of cations and clay in the soil, while the latter was related tohigher concentrations of exchangeable aluminium in the soil surface. The threecerrado physiognomies – campo cerrado, cerradosensu stricto, and cerradão– could not be distinguished considering plant density and the analysedsoil features.  相似文献   

2.
Multiple-quantum 2D and 3D bi-directional HCNCH experiments are presented for the correlation of base and ribose protons/carbons in 13C/15N labeled HIV-1 TAR RNA. In both 2D and 3D experiments, the magnetization of H1 is transferred to H6/H8 and H1 through H1-C1-N1/9-C6/8-H6/8 and H1-C1-N1/9-C1-H1 pathways, and the magnetization of H6/8 is transferred to H1 and H6/8 through H6/8-C6/8-N1/9-C1-H1 and H6/8-C6/8-N1/9-C6/8-H6/8 pathways. Chemical shifts of four different nuclei (H1, C1, C6/8 and H6/8) are sampled in the 2D experiment. The correlation of base and ribose protons/carbons is established by the rectangular arrangement of crossover and out-and-back peaks in the proton/carbon correlated spectrum. The rectangular connections can be further resolved using the nitrogen dimension in a 1H/13C/15N 3D experiment. Furthermore, by taking advantage of the well separated chemical shifts of N1 (pyrimidine) and N9 (purine), the 2D spectrum can be simplified into two sub-spectra based on their base type. Both experiments were tested on a 13C/15N labeled 27-mer HIV-1 TAR RNA containing a UUCG hairpin loop.  相似文献   

3.
The sialidase of swine influenza A viruses of N1 and N2 subtypes, isolated from 1930 to 1992, was studied for substrate specificity with ganglio-series, lacto-series type II and GM3 gangliosides containing Neu5Ac2-3Gal, Neu5Gc2-3Gal and Neu5Ac2-6Gal linkages. All viral sialidases tested showed that the activity for hydrolysing substrates with Neu5Ac2-3Gal was higher than the activities with Neu5Gc2-3Gal and Neu5Ac2-6Gal linkages. When GM1b, GM3 and sialylparagloboside were used as substrates, the earliest strain (A/Wisconsin/15/30 H1N1, isolated in 1930) showed the activity ratio of Neu5Ac2-6Gal to Neu5Ac2-3Gal to be 0.13:0.2, and the ratio Neu5Gc2-3Gal/Neu5Ac2-3Gal to be 0.19:0.37, while those strains isolated from 1978 to 1992 exhibited ratios of 0.29:0.58 for Neu5Ac2-6Gal/Neu5Ac2-3Gal and 0.51:0.76 for Neu5Gc2-3Gal/Neu5Ac2-3Gal. The above results indicate that the substrate specificities of sialidases from swine influenza A viruses towards sialyl linkages and the molecular species of sialic acid are related to the year of isolation, i.e. strains isolated after 1978 exhibited higher activity towards Neu5Ac2-6Gal and Neu5Gc2-3Gal linkages when compared with strains isolated in an earlier year, 1930.Abbreviation Neu5Ac 5-N-acetylneuraminic acid - Neu5Gc 5-N-glycolyneuraminic acid - Gal d-galactose - Glc d-glucose - Cer Ceramide - II3(Neu5Ac)Lac Neu5Ac2-3Gal1-4Glc - GM3(Neu5Ac2-3Gal) Neu5Ac2-3Gal1-4Glc1-Cer - GM3(Neu5Gc2-3Gal) Neu5Gc2-3Gal1-4Glc1-Cer - GM1b(Neu5Ac2-3Gal) Neu5Ac2-3Gal1-3GalNac1-4Gal1-4Glc1-Cer - GMlb(Neu5Gc2-3Gal) Neu5Gc2-3Gal1-3GalNAc1-4Gal1-4Glc1-Cer - IV3(Neu5Ac)nLc4Cer Neu5Ac2-3Gal1-3GlcNAc1-4Gal1-4Glc1-Cer - IV3(Neu5Gc)nLc4Cer Neu5Gc2-3Gal1-3GlcNAc1-4Gal1-4Glc1-Cer - IV6(Neu5Ac)nLc4Cer Neu5Ac2-6Gal1-3GlcNAc1-4Gal1-4Glc1-Cer - TDC taurodeoxycholate.  相似文献   

4.
Fowl plague virus, strain Dutch, was metabolically labeled withd-[2-3H]mannose, or withd-[6-3H]glucosamine, and the small subunit (HA2; 0.8 mg in total) of the viral hemagglutinin was isolated by preparative sodium dodecylsulfate-polyacrylamide gel electrophoresis. After proteolytic digestion, the radioactive oligosaccharides were sequentially liberated from the glycopeptides by treatment with different endo--N-acetylglucosaminidases and with peptide:N-glycosidase or, finally, by hydrazinolysis. In this manner, four groups of glycans could be obtained by consecutive gel filtrations and were subfractionated by HPLC. The structures of the individual oligosaccharides were analyzed by micromethylation, by acetolysis or by digestion with exoglycosidases. The major species amongst the high mannose glycans at Ans-406 of the viral glycopolypeptide were found to be Man1-2Man1-3(Man1-2Man1-6)Man1-6(Man1-2Man1-2Man1-3)Man1-4GlcNac1-4GlcNAc and Man1-3(Man1-2Man1-6)Man1-6(Man1-2Man1-2Man1-3)Man1-4GlcNAc1-4GlcNAc, while the complex glycans at Asn-478 are predominantly GlcNAc1-2Man1-3(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc (lacking, in part, one of the outerN-acetylglucosamine residues) and GlcNAc1-2Man1-3(Gal1-4GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc.Abbreviation BSA bovine serum albumin - endo D (F,H) endo--N-acetyl-d-glucosaminidase D (F,H) - HA hemagglutinin (HA1, large subunit of HA - HA2 small subunit - FPV fowl plague virus - PNGase F peptide:N-glycosidase F - SDS sodium dodecylsulfate  相似文献   

5.
Conclusion Even a cursory look at the ethnographic literature on other Northwest Coast societies reveals some striking similarities with the Tlingit way of conceptualizing aristocrats as special persons. Thus the Kwakiutl referred to their chiefs as real or complete people, who were heavier than commoners. The Coast Tsimshian called their highest aristocrats real or ripe persons, in contrast to the low-ranking ones, who were described as unhealed or green. The Coast Tshimshian also referred to their chiefs as strong, heavy, and solid like a rock. The neighboring Gitksan contrasted the chiefs, described as people who were good and clean and stayed put, with the commoners, who were said to be dirty, ignorant, and always moving around. Because spirits of the dead liked to return to persons who were clean and showed respect by giving away wealth and feasts, there was considerable moral and practical pressure on the aristocrats to remain pure, train knowledgeable and clean heirs, and continue potlatching. Finally, among the Haida, rank was tied to a wider system of symbolic classification, associating aspects of food, space, clothing, ritual pollution and the ethic of industry with attributes of seniority.While some of the symbolic associations of aristocratic status are culture specific, others are present in several, if not all, of the NWC cultures. What we need is a comparative symbology of aristocratic status, which would combine the reanalysis of the existing ethnographic data with the introduction of some new materials that can still be obtained in the field. Such work would be the best tribute to Irving Goldman himself and to our common illustrious ancestors—Franz Boas and Marcel Mauss.Sergei Kan is Professor of Anthropology at Dartmouth College.  相似文献   

6.
As part of a program to explore the structural requirement of N-glycans in the carbohydrate-mediated biological interactions, N-linked pentasaccharide core structure was stereochemically modified in terms of glycosidic linkage. Three isomers, -D-Man-(13)-[-D-Man-(16)]--D-Man-(14)--D-GlcNAc-(14)--D-GlcNAc-L-Asn, -D-Man-(13)-[-D-Man-(16)]--D-Man-(14)--D-GlcNAc-(14)--D-GlcNAc-L-Asn, and -D-Man-(13)-[-D-man-(16)]--D-Man-(14)--D-GlcNAc-(14)--D-GlcNAc-L-Asn, were synthesized. Synthesis of the pentasaccharide with natural linkage is also described.  相似文献   

7.
《Glycoconjugate journal》1995,12(5):721-728
The expression of neutral glycosphingolipids (GSLs) and gangliosides was investigated in cryosections of normal mouse skeletal muscle and in muscle of mice with neuromuscular diseases using indirect immunofluorescence microscopy. Transversal and longitudinal sections were immunostained with specific polyclonal antibodies against lactosylceramide, lacto-N-neotetraosylceramide, globoside, GM3(Neu5Ac), GM3(Neu5Gc) and GM1(Neu5Ac) as well as monoclonal anti-Forssman GSL antibody. In normal CBA/J mouse muscle (control) the main immunohistochemically detected ganglioside was GM3(Neu5Ac) followed by moderately expressed GM3(Neu5Gc) and GM1. The neutral GSLs lactosylceramide and globoside were stained with almost identical, high fluorescence intensity. Low amounts of lacto-N-neotetraosylceramide and trace quantities of Forssman GSL were immunostained. All GSLs were detected in the sarcolemma, but also in considerable amounts at the intracellular level. Mice with neuromuscular diseases were the A2G-adr mouse mutant (a model for human recessive myotonia of Becker type), the BL6-wr mutant (a model for motor neuron disease) and the BL10-mdx mouse mutant (a model for human Duchenne muscular dystrophy). No changes in GSL expression were found in the A2G-adr mouse, while muscle of the BL6-wr mouse showed increased intensity of immunofluorescence in stainings with anti-lactosylceramide and anti-GM3(Neu5Ac) antibodies. Muscle of BL10-mdx mice showed the most prominent changes in GSL expression with reduced fluorescence intensity for all antibodies. Major differences were not observed in the intensities of GSLs, but there were significant differences in the patterns of distribution on plasma membrane and at the subcellular level. The exact nature and pathogenesis of these changes should be elucidated since such investigations could furnish advances in understanding the functional role of neutral GSLs and gangliosides in normal as well as in diseased muscle. Abbreviations: BSA, bovine serum albumin; DAPI, 4, 6-diamidine-2-phenylindole-dihydrochloride; DTAF, dichlorotriazinylamino-fluorescein; GSL(s), glycosphingolipid(s); Neu5Ac,N-acetylneuraminic acid; Neu5Gc,N-glycolylneuraminic acid [53]; PBS, phosphate buffered saline. The designation of the following glycosphingolipids follows the IUPAC-IUB recommendations [54] and the nomenclature of Svennerholm [55]. Lactosylceramide or LacCer, Gal1-4Glc1-1Cer; gangliotriaosylceramide or GgOse3Cer, GalNAc1-4Gal1-4Glc1-1Cer; globotriaosylceramide or GbOse3Cer, Gal1-4Gal1-4Glc1-1Cer; gangliotetraosylceramide or GgOse3Cer, Gal1-3GalNAc1-4Gal1-4Glc1-1Cer; globotetraosylceramide or GbOse4Cer, GalNAc1-3Gal1-4Gal1-4Glc1-1Cer; lacto-N-neotetraosylceramide or nLcOse4Cer, Gal1-4GlcNAc1-3Gal1-4Glc1-1Cer; Forssman GSL or GbOse5Cer, GalNAc1-3GalNAc1-3GAl1-4Gal1-4Glc1-1Cer; GM3, II3Neu5Ac-LacCer; GM1, II3Neu5Ac-GgOse4Cer.  相似文献   

8.
Summary Two specific -N-acetylglucosaminyltransferases involved in the branching and elongation of mucin oligosaccharide chains, namely, a 1,6 N-acetylglucosaminylsaminyltransferase that transfers N-acetylglucosamine from UDP-N-acetylglucosamine to Gal3GalNAc-Mucin to yield Gal3(GlcNAc6)GalNAc-Mucin and a 3-N-acetylglucosaminyl transferase that transfers N-acetylglucosamine from UDP-N-acetylglucosamine to Gal3(GlcNAC6)GalNAc-mucin to yield GlcNAc3Gal3 (GlcNAc6)GalNAc-Mucin were purified from the microsomal fraction of swine trachea epithelium. The 1,6-N-acetylglucosaminyltransferase was purified about 21,800-fold by procedures which included affinity chromatography on DEAE columns containing bound asialo Cowper's gland mucin glycoprotein with Gal1,3GalNAc side chains. The apparent molecular weight estimated by gel filtration was found to be about 60 Kd. The purified enzyme showed a high specificity for Gal1,3GalNAc chains and the most active substrates were mucin glycoproteins containing these chains. The apparent Km of the 6-glucosaminyltrans-ferase for Cowper's gland mucin glycoprotein containing Gal1,3GalNAc chains was 0.53 µM; for UDP-N-acetylglucosamine, 12 µM; and for Gal 1,3GalNAc NO2ø, 4 mM. The activity of the 6-glucosaminyltransferase was dependent on the extent of glycosylation of the Gal3GalNAc chains in Cowper's gland mucin glycoprotein.The best substrate for the partially purified 3-Glucosaminyltransferase was Cowper's gland mucin glycoprotein containing Gal1,3(GlcNAc6)GalNAc side chains. This enzyme showed little or no activity with intact sialylated Cowper's gland mucin glycoprotein or derivatives of this glycoprotein containing GalNAc or Gal1,3GalNAc side chains.The radioactive oligosaccharides formed by these enzymes in large scale reaction mixtures were released from the mucin glycoproteins by treatment with alkaline borohydride, isolated by gel filtration on Bio-Gel P-6 and characterized by methylation analysis and sequential digestion with exoglycosidases. The oligosaccharide products formed by the 6- and 3-glucosaminyltransferases were shown to be Gal3(GlcNAC6) GalNAc and GlcNAc3 Gal3(GlcNAC6)GalNAc respectively.Taken collectively, these results demonstrate that swine trachea epithelium contains two specific N-acetylglucosaminyltransferases which catalyze the initial branching and elongation reactions involved in the synthesis of O-linked oligosaccharide chains in respiratory mucin glycoproteins. The first enzyme a 6-glucosaminyltransferase converts Gal3GalNAc chains in mucin glycoproteins to Gal3(GlcNAc6)GalNAc chains. This product is the substrate for a second 3-glucosaminyltransferase which converts the Gal3(GlcNAc6)GalNAc chains to GlcNAc3Gal(GlcNAc6)GalNAc chains in the glycoprotein. The 3-glucosaminyltransferase did not utilize Gal3GalNAc chains as a substrate and this results in an ordered sequence of addition of N-acetylglucosamine residues to growing oligosaccharide chains in tracheal mucin glycoproteins.Abbreviations NeuNAc N-acetylneuraminic acid - GalNAcol N-acetylgalactosaminitol - CGMG Cowper's gland mucin glycoprotein - GalNAc-CGMG Cowper's gland mucin glycoprotein containing GalNAc side chains O-glycosidically linked to serine or threonine - Gal3GalNAc-CGMC Cowper's gland mucin glycoprotein containing Gal3GalNAc side chains - MES 2-(N-morpholino) Ethane Sulfonic acid - PBS Phosphate Buffered Saline  相似文献   

9.
-N-Acetyl-d-hexosaminidase from Aspergillus oryzae catalysed the stereo- and regiospecific formation of the 6-O-benzylated disaccharide derivatives GalNAc1-3(6- OBn)Gal-SEt and GlcNAc1-3(6-OBn)Gal-SEt, which were obtained in transglycosylation reactions employing ethyl 6- O-benzyl-1-thio--d-galactopyranoside as acceptor. Preparative amounts of the chitobiose derivative GlcNAc1- 3GlcNAc-OPhNO2-p was prepared as well. - N-Acetyl-d-hexosaminidase from bovine testes catalysed the specific synthesis of GlcNAc1-3(6-OBn)GlcNH2-SEt and GalNAc1-3(6-OBn)GlcNH2-SEt, employing ethyl 2-amino-6-O-benzyl-2-deoxy-1-thio--d-glucopyranoside as acceptor. -d-Glucuronidase from E. coli was found to catalyse the formation of GlcA1-3(6-OBn)GlcNH2- SEt employing the same acceptor.  相似文献   

10.
Lentil is a protein-rich pulse, grown mainly in developing countries as a rain-fed crop in nutrient-poor soils. Hence, the importance of root traits for efficient capture of soil nutrients and water can be crucial to its economical yield. Little is known about the lentil root system and even less about its relationship to grain yield. We compared the root system of two Bangladeshi lentil varieties, Barimasur-3 (BM-3) and Barimasur-4 (BM-4), in a pot experiment and related it to their multi-location grain yield in the fields. BM-4 maintained faster root development both at an early growth stage (20days after sowing) and at flowering (60days) compared to BM-3. The roots of BM-4 penetrated the 25cm depth of the soil profile after 19±1days and while those of BM-3 took 24±2days to reach the same depth. The roots of BM-4 were covered with denser (26±3mm–1) and longer (0.48±0.11) root hairs than BM-3 (density 17±2mm–1, length 0.32±0.09mm). The differential presence of root hairs increased the effective length of root system of BM-4 by 12 times and that of BM-3 by five times. The lentil varieties did not differ in their ability to induce pH change and acid phosphatase activity in rhizosphere. In the pot experiment, the uptake of macro-nutrients (K, P, Ca, and Mg) as well as micro-nutrients (Fe, Mn, Zn, Cu, B and Mo) by BM-4 was significantly higher, compared to BM-3. The varieties produced the same amount of shoot biomass. At five of six agro-ecological distinct field locations in Bangladesh, BM-4 gave significantly higher (10–20%) grain yield than BM-3. Linked with the higher grain yield, the benefit-cost ratio (BCR) of BM-4 was 3.14 and that of BM-3 were 2.62, indicating that BM-4 provided better return per unit investment, compared to BM-3, supported by the better root morphology and higher nutrient uptake. This may be one of the reasons supporting the popularity and preferred adoption of BM-4 among the Bangladeshi farmers, who grow lentil mainly on nutrient-poor soils. The results indicate the benefits of selection and breeding for superior root traits for better agro-economics.  相似文献   

11.
The present study was undertaken to determine the effects of AT1 receptor blockade which occurred in response to losartan, on the extracellular matrix (ECM) degradation process in the Bio 14.6 (n = 12) and Bio 53.58 (n = 12) strains which are referred as models of hypertrophic and dilated cardiomyopathy, respectively. The administration of losartan (30 mg/kg/day) in hamsters from 10–20 weeks of age reduced the accumulation of the left ventricular collagen matrix in both of the Bio 14.6 and the Bio 53.58 strains. According to the RTPCR, the levels of mRNA for matrix metalloproteinase (MMP) and the tissue inhibitor of MMP (TIMP) were examined. MMP1, 2, 3, and 9 were more enhanced in both myopathic strains than in the control F1 strains. With losartan, the levels of MMP1, 2, 9, TIMP1 and 2 decreased in the both strains but those for MMP3 did not in Bio 14.6 strains. TIMP3 and 4 mRNA levels did not change in any of the experimental hamsters, whether treated or untreated with losartan. The Western blots also showed similar observations in the both strains as seen in mRNA expressions although MMP2 in the Bio 53.58 strains did not differ between treated and untreated with losartan. Although losartan has an inhibitory effect on collagen accumulation in the development of cardiomyopathy, MMPs (1, 2, 9) and TIMPs (1, 2) seem to be susceptible to responding to losartan in Bio cardiomyopathic hamsters.  相似文献   

12.
Sources and sinks of aquatic carbon in a peatland stream continuum   总被引:2,自引:0,他引:2  
Streams draining peatland systems contain a number of different C-species, all of which are linked either directly or indirectly to the cycling of C in the terrestrial environment. Concentrations and fluxes of dissolved, particulate and gaseous forms of carbon were measured along a network of streams draining an acidic peatland catchment (46.3km2) in NE Scotland. The main aim was to identify sources and sinks of all the major forms of C in the drainage network and use this to develop a conceptual understanding of the evolution of streamwater chemistry along a peatland stream continuum. The investigation included a small-scale intra-catchment study of three contiguous sites in a 1.3km2 headwater catchment (Brocky Burn) and a larger scale integrated study of seven sites. Mean annual fluxes of the main carbon species varied from 115–215 (DOC), 8.15–97.0 (POC), 0.32–6.90 (HCO3--C) and 2.62–10.4 (free CO2-C)kgCha–1year–1; all contributed to the overall carbon flux to varying degrees. Methane-C was only measurable at sites within areas of deep peat (<0.01–0.09kgCha–1year–1). Downstream spatial changes in the intra-catchment study (Brocky Burn) were characterised by a decrease in DOC, CO2-C and CH4-C and an increase in POC fluxes over a distance of 1.1km from the Upper to the Lower sites. In the context of the integrated catchment study estimated losses and gains of carbon from the water column showed no net change in DOC, a large decrease in POC (–55%) and a slight increase in (HCO3--C) (+7.7%) and CO2-C (+4.5%). A significant decrease in the CO2-C flux: HCO3-C flux ratio with distance downstream from the stream source, illustrates the importance of outgassing of CO2 from streams draining peatland C reservoirs. These data are interpreted in the context of losses and gains of the various components of the aquatic C flux along the peatland stream continuum.  相似文献   

13.
Dong A  Ye M  Guo H  Zheng J  Guo D 《Biotechnology letters》2003,25(4):339-344
Of 49 microbial strains screened for their capabilities to transform ginsenoside Rb1, Rhizopus stolonifer and Curvularia lunata produced four key metabolites: 3-O-[-d-glucopyranosyl-(1,2)--d-glucopyranosyl]- 20-O-[-d-glucopyranosyl]-3,12, 20(S)-trihydroxydammar-24-ene (1), 3-O-[-d-glucopyranosyl-(1,2)--d- glucopyranosyl]-20-O-[-d-glucopyranosyl]-3,12, 20(S)-trihydroxydammar-24-ol (2), 3-O-[-d-gluco- pyranosyl-(1,2)--d-glucopyranosyl]-3, 12, 20(S)-trihydroxydammar-24-ene (3), and 3-O--d-glucopyranosyl-3, 12, 20(S)-trihydroxydammar-24-ene (4), identified by TOF-MS, 1H- and 13C-NMR spectral data. Metabolites 1, 3 and 4 were from the incubation with R. stolonifer, and 1 and 2 from the incubation with C. lunata. Compound 2 was identified as a new compound.  相似文献   

14.
Purpose The first objective of this study was to investigate in vitro effects of -galactosylceramide (GalCer) on the proliferation of umbilical cord blood (UCB) natural killer T (NKT) cells and enhancement of their cytotoxicity. The second one is to examine whether purified NKT cells could affect the cytotoxicity of UCB-NK cells either in the presence or absence of dendritic cells (DCs).Methods Mononuclear cells (MNCs) from UCB were cultured for 2 weeks in the presence of IL-2 (100 U/ml), with or without GalCer. The effect of neutralizing monoclonal antibodies (MoAb) against TCRV24 and CD1d was also examined. TCRV24 V11 double positive NKT cells were purified by FACS sorter and then cocultured with syngeneic isolated UCBCD56+NK cells in either the presence or absence of DCs. The cytotoxicity against various malignant cell targets and cytokine production was determined.Results The addition of GalCer induced human NKT cells to proliferate in UCB-MNCs to a greater extent than in adult PB-MNCs. However, it suppressed the cytotoxic activity against malignant cell targets. Anti-TCRV24 and CD1d MoAb recovered the cytotoxicity by inhibiting the proliferation of UCB-NKT cells. NKT cells cocultured with auto-DCs significantly increased NK cell cytotoxicity against K562, and Raji cells and produced IFN- at much higher levels than UCB-NKT cells alone.Conclusion In UCB samples, GalCer–pulsed DCs and NKT cells acted together to enhance NK cytotoxicity in vitro.  相似文献   

15.
    
A partially purified preparation of 1,3-fucosyltransferase(s) from human milk was used to [14C]fucosylate oligosac-charides containing Gal1-4GlcNAc units. Substitution ofN-acetyllactosamine at position 3 with a -linkedN-acetylglucosamine enhanced the reactivity of the acceptor, whereas similar substitution at position 6 was inhibitory. Thus, the trisaccharide GlcNAcl-6Gal1-4GlcNAc (5), the branched tetrasaccharide GlcNAc1-3(GlcNAc1-6)Gal1-4GlcNAc (11) and the triply branched decasaccharide GlcNAc1-3(GlcNAc1-6)Gall-4GlcNAc1-3[GlcNAc1-3(GlcNAc1-6)Gal1-4GlcNAc1-6]Gal1-4GlcNAc (26) gave remarkably poor yields of 1,3-fucosylated products in comparison to GlcNAc1-3Gal1-4GlcNAc (3). 1,4-Galactosyl derivatives of5 and11, however, gave good yields of 1,3-fucosylated products, but the fucosylation was restricted to the distalN-acetyllactosamine units of Gal1-4GlcNAc1-6Gal1-4GlcNAc (16), Gal1-4GlcNAc1-3(Gal1-4GlcNAc1-6)Gal1-4GlcNAc (18) and also in Gal1-3Gal1-4GlcNAc1-3(Gal1-3Gal1-4GlcNAc1-6)Gal1-4GlcNAc (22). Immobilized wheat germ agglutinin (WGA), possessing high affinity for16 [1], revealed no affinity for the fucosylated derivative Gal1-4(Fuc1-3)GlcNAc1-6Gal1-4GlcNAc (17). The isomeric heptasaccharides Gal1-4(Fuc1-3)GlcNAc1-3(Gal1-4GlcNAc1-6)Gal1-4GlcNAc (19) and Gal1-4GlcNAc1-3[Gal1-4(Fuc1-3)GlcNAc1-6]Gal1-4GlcNAc (20) were readily separated from each other on WGA-agarose, and so were the isomeric nonasaccharides Gal1-3Gal1-4(Fuc1-3)GlcNAc1-3(Gal1-3Gal1-4GlcNAc1-6)Gal1-4GlcNAc (23) and Gal1-3Gal1-4GlcNAc1-3[Gal1-3Gal1-4(Fuc1-3)GlcNAc1-6]Gal1-4GlcNAc (24).  相似文献   

16.
A novel mono-sulfated glycosphingolipid based on the gangliotriaose core structure was isolated from rat kidney. The isolation procedure involved extraction of lipids with chloroform/methanol, mild alkaline methanolysis, column chromatographies with anion exchangers and silica beads. The structure was characterized by compositional analysis, FTIR spectroscopy, methylation analysis,1H-NMR spectroscopy and negative-ion liquid secondary ion mass spectrometry (LSIMS) using the intact glycolipid and its desulfation product. The two dimensional chemical shift correlated spectroscopy provided information on the sugar sequence as well as anomeric configurations, and indicated the presence of a 3-O-sulfatedN-acetylgalactosamine within the molecule. Negative-ion LSIMS with high- and low-energy collision-induced dissociation defined the sugar sequence and ceramide composition, confirming the presence of a sulfatedN-acetylgalactosamine at the non-reducing terminus. From these results, the complete structure was proposed to be HSO3-3GalNAc1-4Gal1-4Glc1-1Cer (Gg3Cer III3-sulfate, SM2b). Abbreviations: Abbreviations for sulfated glycolipids [17] follow the modifications of the nomenclature system of Svennerholm for gangliosides [37], and the designation of the other glycosphingolipids follows the IUPAC-IUB recommendations [38]. Cer, ceramide; LacCer, lactosylceramide, Gal1-4Glc1-1Cer; Gg3Cer, gangliotriaosylceramide, GalNAc1-4Gal1-4Glc1-1Cer; Gg4Cer, gangliotetraosylceramide, Gal1-3GalNAc1-4Gal1-4Glc1-1Cer; iGb4Cer, isoglobotetraosylceramide, GalNAc1-3Gal1-3Gal1-4Glc1-1Cer; Gb4Cer, globotetraosylceramide, GalNAc1-3Gal1-4Gal1-4Glc1-1Cer; SM4s, galactosylceramide sulfate, GalCer I3-sulfate; SM3, lactosylceramide sulfate, LacCer II3-sulfate; SM2a, Gg3Cer II3-sulfate; SM2b, Gg3Cer III3-sulfate; SB2, Gg3Cer II3,III3-bis-sulfate; SM1a, Gg4Cer II3-sulfate; SM1b, Gg4Cer IV3-sulfate; SB1a, Gg4Cer II3,IV3-bissulfate; GLC, gas-liquid chromatography; GC-MS, gas chromatography-mass spectrometry; DQF, double quantum filtered; COSY, chemical-shift-correlated spectroscopy; LSIMS, liquid secondary ion mass spectrometry; CID, collision-induced dissociation; MS/MS, tandem mass spectrometry.  相似文献   

17.
K99 lectin fromEscherichia coli was purified and biotinylated via its carboxyl groups using biocytin hydrazide and a water soluble carbodiimide. Biotinylation of two out of the nine carboxyl groups was sufficient to permit detection of the lectin by avidin and did not cause any loss of the haemagglutinating activity. It was demonstrated that the biotinylated K99 lectin retained other important properties of native K99 and that it will probably become a very sensitive detecting reagent. Indeed, it was able to bind to HeLa cells, as do intact bacteria carrying K99 fimbriae, and also to recognizeN-glycolyl-neuraminyl-lactosyl-ceramide in an overlay binding assay. Abbreviations: NeuAc,N-acetylneuraminic acid; NeuGc,N-glycolylneuraminic acid; PBS, phosphate buffered saline (0.9% NaCl containing 150mm sodium phosphate, pH 7.2); LPS, lipopolysaccharide; BCHZ, biocytin hydrazide; EDC, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide; BSA, bovine serum albumin; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; DMEM, Dulbecco's modified Eagle medium. For the gangliosides, trivial names and structures are given according to the recommendations in [43]. NeuAc2-3Gal1-4Glc1-1Cer (NeuAc-GM3); NeuGc2-3Gal1-4Glc1-1Cer (NeuGc-GM3); GalNAc1-4(NeuAc2-3)Gal1-4Glc1-1Cer (GM2); NeuAc2-8NeuAc2-3Gal1-4Glc1-1Cer (GD3); Gal1-3GalNAc1-4(NeuAc2-3)Gal1-4Glc1-1Cer (GM1); NeuAc2-3Gal1-3GalNAc1-4(NeuAc2-3)Gal1-4Glc1-1Cer (GD1a); Gal1-3GalNAc1-4(NeuAc2-8NeuAc2-3)Gal1-4Gle1-1Cer (GD1b); NeuAc2-3Gal1-3GalNAc1-4(NeuAc2-8NeuAc2-3) Gal1.-4Glc1-1Cer (GT1b). NeuGc2-3Gal1-4GleNAc1-4Gal1-4Glc1-1Cer (NeuGc-SPG).  相似文献   

18.
Summary The -glucuronidase staining characteristics of isolated T cell populations and the T and T enriched fractions derived of them were studied. T lymphocytes were obtained from purified T lymphocytes by ox-IgG rosette sedimentation. The rosette-forming cells in the pellet were referred to as T lymphocytes, whereas the lymphocytes in the interface were referred to as T depleted or T lymphocytes. B cells were studied on rosetted mononuclear cells with either mouse erythrocytes or with Staphylococcus Aureus (Cowan I) bacteria, after a preceeding polyvalent anti-human Ig treatment of the cells. While B cells showed mostly no reactivity, T and T cells were respectively characterised by a dot-like and granular pattern of reactivity. These findings are in agreement with those observed by others after -naphthyl-acetate esterase or acid phosphatase staining. Within the T lymphocyte fraction, the T non-, non lymphocytes seemed to have a granular pattern of reactivity. The same staining pattern was found in non-B, non-T lymphocytes.  相似文献   

19.
In this study the comparative TLC immunostaining investigation of neutral GSLs and gangliosides from human skeletal and heart muscle is described. A panel of specific polyclonal and monoclonal antibodies as well as the GM1-specific choleragenoid were used for the overlay assays, combined with preceding neuraminidase treatment of gangliosides on TLC plates. This approach proved homologies but also quantitative and qualitative differences in the expression of ganglio-, globo- and neolacto-series neutral GSLs and gangliosides in these two types of striated muscle tissue within the same species. The main neutral GSL in skeletal muscle was LacCer, followed by GbOse3Cer, GbOse4Cer, nLcOse4Cer and monohexosylceramide, whereas in heart muscle GbOse3Cer and GbOse4Cer were the predominant neutral GSLs beside small quantities of LacCer, nLcOse4Cer and monohexosylceramide. No ganglio-series neutral GSLs and no Forssman GSL were found in either muscle tissue. GM3(Neu5Ac) was the major ganglioside, comprising almost 70% in skeletal and about 50% in cardiac muscle total gangliosides. GM2 was found in skeletal muscle only, while GD3 and GM1b-type gangliosides (GM1b and GD1) were undetectable in both tissues. GM1a-core gangliosides (GM1, GD1a, GD1b and GT1b) showed somewhat quantitative differences in each muscle; lactosamine-containing IV3Neu5Ac-nLcOse4Cer was detected in both specimens. Neutral GSLs were identified in TLC runs corresponding to e.g. 0.1 g muscle wet weight (GbOse3Cer, GbOse4Cer), and gangliosides GM3 and GM2 were elucidated in runs which corresponded to 0.2 g muscle tissue. Only 0.02 g and 0.004 g wet weight aliquots were necessary for unequivocal identification of neolacto-type and GM1-core gangliosides, respectively. Muscle is known for the lowest GSL concentration from all vertebrate tissues studied so far. Using the overlay technique, reliable GSL composition could be revealed, even from small muscle probes on a sub-orcinol and sub-resorcinol detection level. Abbreviations: ATCC, American Type Culture Collection; GSL(s), glycosphingolipid(s); HPLC, high performance liquid chromatography; HPTLC, high performance thin layer chromatography; Neu5Ac, N-acetylneuraminic acid; Neu5Gc, N-glycolylneuraminic acid [78]; PBS, phosphate buffered saline. The designation of the following glycosphingolipids follows the IUPAC-IUB recommendations [79] and the ganglioside nomenclature system of Svennerholm [80]. Lactosylceramide or LacCer, Gal1-4Glc1-1Cer; gangliotriaosylceramide or GgOse3Cer, GalNAc1-4Gal1-4Glc1-1Cer; gangliotetraosylceramide or GgOse4Cer, Gal1-3GalNAc1-4Gal1-4Glc1-1Cer; globotriaosylceramide or GbOse3Cer, Gal1-4Gal1-4Glc1-1Cer; globoside or globotetraosylceramide or GbOse4Cer, GalNAc1-3Gal1-4Gal1-4Glc1-1Cer; Fo or Forssman GSL, GalNAc1-3GalNAc1-3Gal1-4Gal1-4Glc1-1Cer; paragloboside or lacto-N-neotetraosylceramide or nLcOse4Cer, Gal1-4GlcNAc1-3Gal1-4Glc1-1Cer; lacto-N-norhexaosylceramide or nLcOse6Cer, Gal1-4GlcNAc1-3Gal1-4GlcNAc1-3Gal1-4Glc1-1Cer; GM3, II3Neu5Ac-LacCer; GM2, II3Neu5Ac-GgOse3Cer; GM1 or GM1a, II3Neu5Ac-GgOse4Cer; GM1b, IV3Neu5Ac-GgOse4Cer; GD3, II3(Neu5Ac)2-LacCer; GD1a, IV3Neu5Ac,II3Neu5Ac-GgOse4Cer; GD1b, (II3Neu5Ac)2-GgOse4Cer; GD1, IV3Neu5Ac,III6Neu5Ac-GgOse4Cer; GT1b, IV3Neu5Ac,II3(Neu5Ac)2-GgOse4Cer; GQ1b, IV3(Neu5Ac)2, II3(Neu5Ac)2-GgOse4Cer.  相似文献   

20.
The aim of the study was to investigate the relationships between the expression of v, 1, 3, 5, and 6, integrin subunits and clinical parameters in ovarian cancers. Ovarian surface epithelium (OSE) from five donors and tumour samples from 39 patients with an epithelial ovarian cancer (39 primary tumours and 21 associated peritoneal metastases) were analysed using immunohistochemistry on paraffin-embedded or frozen tissue sections. The v and 5 integrin subunits were always present in normal OSE and in tumours. 1 and 3 subunit expression was significantly less frequent in grade 3 than in grade 1–2 tumours. The proportion of stage IV tumours expressing 3 was significantly lower as compared to other stages. The 6 subunit was undetectable in OSE but was expressed in about 40% of primary tumours. For all integrin, there was a strong relationship between the expression in primary tumours and in associated peritoneal metastases. Survival analyses restricted to patients receiving platinum-based chemotherapy did not reveal any relationship between integrin subunit expression and 3-year survival rate, in this limited series of patients. In conclusion, the expression of the various integrin subunits was differentially altered in ovarian carcinoma, evocative of complementary roles of v integrins during tumour development.  相似文献   

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