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1.
Cornelis H. Hokke Jos G. M. van der Ven Johannis P. Kamerling Johannes F. G. Vliegenthart 《Glycoconjugate journal》1993,10(1):82-90
Incubation of synthetic Man\1-4GlcNAc-OMe, GalNAc1-4GlcNAc-OMe, Glc1-4GlcNAc-OMe, and GlcNAc1-4GlcNac-OMe with CMP-Neu5Ac and rat liver Gal1-4GlcNAc (2-6)-sialyltransferase resulted in the formation of Neu5Ac2-6Man1-4GlcNAc-OMe, Neu5Ac2-6GalNAc1-4GlcNAc-OMe, Neu5Ac2-6Glc1-4GlcNAc-OMe and Neu5Ac2-6GlcNAc1-4GlcNAc-OMe, respectively. Under conditions which led to quantitative conversion of Gal1-4GlcNAc-OEt into Neu5Ac2-6Gal1-4GlcNAc-OEt, the aforementioned products were obtained in yields of 4%, 48%, 16% and 8%, respectively. HPLC on Partisil 10 SAX was used to isolate the various sialyltrisaccharides, and identification was carried out using 1- and 2-dimensional 500-MHz1H-NMR spectroscopy.Abbreviations 2D
2-dimensional
- CMP
cytidine 5-monophosphate
- CMP-Neu5Ac
cytidine 5-monophospho--N-acetylneuraminic acid
- COSY
correlation spectroscopy
- DQF
double quantum filtered
- HOHAHA
homonuclear Hartmann-Hahn
- MLEV
composite pulse devised by M. Levitt
- Neu5Ac
N-acetylneuraminic acid
- Neu5Ac2en
2-deoxy-2,3-didehydro-N-acetylneuraminic acid 相似文献
2.
Summary A mutant strain of Rhodococcus australis CSIR-236.457 which accumulates 3a-H-4-(3-propionic acid)-5-hydroxy-7a-methylhexahydro-indan-1-one--lactone from cholesterol, stigmasterol and -sitosterol was studied. The product is produced in a 60% molar yield in a dilute black strap molasses medium containing 6–12g/l cholesterol after a 72 hour fermentation period. 相似文献
3.
Summary The effect of long-term treatment (52 weeks) with high doses of 17-estradiol (1.28 mg/kg/week intramuscularly) on gonadotrophs was studied in the pituitary gland of the beagle bitch. For immunochemical staining the immunoperoxidase technique and antisera to the specific beta () subunits of FSH and LH were employed. For control purposes antisera to the following hormones were also used: bovine TSH, canine GH, canine PRL and porcine ACTH1. In the pars distalis and pars tuberalis of control bitches, in addition to the cells which react solely with antisera to either LH or FSH, most cells were reactive to both antisera. The cells stained for FSH were less numerous than those shown to contain LH. TSH, PRL, GH and ACTH/MSH were localized in distinctly different cell types in the pars distalis of all control animals. In the treated bitches, almost complete regression of cells classically identified as gonadotrophs and stained for LH was observed. On the other hand, using the antiserum to FSH, selective immunochemical staining was localized in cells fitting the morphological characteristics of TSH cells. All these cells were also stained for TSH. However, a few cells were also shown to react solely with the antiserum to TSH. These cells, which seem to contain both TSH and FSH, were further clearly differentiated from PRL, GH and ACTH/MSH cells on the basis of their cytological features, intraglandular distribution and by immunochemical double staining. These observations support the concept that the one cell-one hormone theory may not necessarily apply to the glycoprotein hormones of the dog pituitary gland.Abbreviations of Hormones cited in this Paper ACTH
Adrenocorticotropin
- FSH
Follicle Stimulating Hormone
- GH
Growth Hormone
- LH
Luteinizing Hormone
- MSH
Melanocyte Stimulating Hormone
- PRL
Prolactin
- TSH
Thyrotropin
The authors are grateful to Mrs. K. Oertel for carrying out the experimental work on animals, to Mrs. B. Schilk and Miss U. Tüshaus for their excellent technical assistance, and to Dr. P. Günzel for his advice and encouragement 相似文献
4.
Åke Sjöholm 《Bioscience reports》1996,16(5):415-423
The insulin-producing pancreatic islet -cell, characterized by low proliferative potential, is normally not responsive to the polypeptide epidermal growth factor (EGF) or its homolog transforming growth factor (TGF-). Since EGF receptors in other tissues can be up-regulated by other growth factors and by cytokines, we have in this paper investigated whether such a -cell responsiveness to TGF-, or EGF, can be conferred by co-culture with interferon (IFN-), tumor necrosis factor (TNF-) or transforming growth factor (TGF-) in various combinations. To this end, fetal rat pancreatic islets enriched in -cells were isolated and cultured for 3 days with or without 200 pM or 20 nM TGF-. It was found that neither of these TGF- concentrations affected -cell mitogenesis, insulin content or insulin secretion. However, IFN- (1000 U/ml) evoked a modest stimulation of -cell replication, while suppressing insulin secretion and leaving the islet insulin content unaltered. TNF- (1000 U/ml), on the other hand, affected none of these parameters either alone or in any combination with TGF- or IFN-. However, when TNF- or IFN-, either alone or in combination, were combined with the cytokine interleukin-1, this resulted in islet disintegration, whereas the latter cytokine alone did not exert any gross necrotic changes evident by light microscopy. TGF- (500 pM) stimulated insulin secretion but did not influence islet insulin content or -cell mitogenesis either alone or in combination with TGF- (200 pM or 20 nM). In no instance could any mitogenic or secretory response to low or high concentrations of TGF- be conferred by IFN-, TNF- or TGF- whether used alone or in combinations. Hence, responsiveness to TGF- or EGF in the -cell obviously cannot be achieved by any of these peptides.Abbreviations EGF
epidermal growth factor
- IFN-
interferon
- TGF-
transforming growth factor
- TGF-
transforming growth factor
- TNF-
tumor necrosis factor 相似文献
5.
Liying Yan Patricia P Wilkins Gerardo Alvarez-Manilla Su-Il Do David F Smith Richard D Cummings 《Glycoconjugate journal》1997,14(1):45-55
A defined set of oligosaccharides and glycopeptides containing -linked fucose were used to examine the specificity of the immobilized fucose-binding lectin Lotus tetragonolobus agglutinin (LTA1), also known as lotus lectin. Glycans containing the Lewis x determinant (Lex) Gal1-4[Fuc1-3]GlcNAc1-3-R were significantly retarded in elution from high density LTA-Emphaze columns. The lectin also bound the fucosylated lacdiNAc trisaccharide GalNAc1-4[Fuc1-3]GlcNAc. The lectin did not bind glycans containing either sialylLex or VIM-2 determinants, nor did it bind the isomeric Lea, Gal1-3[Fuc1-4]GlcNAc-R. Although 2-fucosyllactose Fuc1-2Gal1-4Glc) was retarded in elution from the columns, larger glycans containing the H-antigen Fuc1-2Gal1-3(4)GlcNAc-R interacted poorly with immobilized LTA. Our results demonstrate that immobilized LTA is effective in isolating glycans containing the Lex antigen and is useful in analyzing specific fucosylation of glycoconjugates. Abbreviations: LTA, Lotus tetragonolobus agglutinin; UEA-1, Ulex europaeus agglutinin-I; LNT, AAL, Aleuria aurantia agglutinin; Gal1-3GlcNAc1-3Gal1-3Glc; LNnT, Gal1-4GlcNAc1-3Gal1-3Glc; Lex, Lewis x antigen; Lea, Lewis a antigen; GDPFuc, guanosine 5-diphosphate--L-fucose 相似文献
6.
Microbial transformation of ginsenoside Rb1 by Rhizopus stolonifer and Curvularia lunata 总被引:2,自引:0,他引:2
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
7.
The induction of synthesis of the secreted enzymes endo-1,4--xylanase (EC 3.2.1.8) and -galactosidase (EC 3.2.1.23) in original and recombinant Penicillium canescens strains has been studied. In all producer strains, the synthesis of these enzymes was induced by arabinose and its metabolite arabitol. The two enzymes differed in the concentration of arabinose required for induction: the synthesis of -galactosidase was most pronounced at 1 mM, whereas maximum synthesis of endo-1,4--xylanase was observed at 5–10 mM. An increase in the number of endo-1,4--xylanase copies in the high-copy-number strain of the fungus suppressed the synthesis of -galactosidase; the synthesis of endo-1,4--xylanase in the high-copy-number recombinant producing -galactosidase was affected to a lesser extent. The amount of enzymes synthesized did not depend on the saccharide used as the sole source of carbon for growing the mycelium prior to its transfer to the inducer-containing medium. 相似文献
8.
Boel Lanne Jeana Cîopraga Jörgen Bergström Cecilia Motas Karl-Anders Karlsson 《Glycoconjugate journal》1994,11(4):292-298
The carbohydrate-binding specificity ofPseudomonas aeruginosa lectin I (PA-I) in iodinated or biotinylated form was studied. A large number of glycosphingolipids, as well as some glycoproteins and neoglycoproteins were used as ligands. Also, inhibition by free saccharides of PA-I binding to glycosphingolipids was tested. It was found that the lectin binds most strongly to terminal and nonsubstituted Gal3Gal- or Gal4Gal-structures.Abbreviations PA-I
Pseudomonas aeruginosa lectin I
- Cer
ceramide
- lactosylceramide
Gal4GlcCer
- iso globotriaosylcerami
Gal3Gal4GlcCer
- globotriaosylceramide
Gal4Gal4GlcCer
- globoside or globotetraosylceramide
GalNAc3Gal4Gal4GlcCer
- Forssman glycolipid
GalNAc3GalNAc3Gal4Gal4GlcCer
- P1 glycolipid
Gal4Gal4GlcNAc3Gal4GlcCer
- lactoneotetraosylceramide
Gal4GlcNAc3Gal4GlcCer
- B5 glycolipid
Gal3Gal4GlcNAc3Gal4GlcCer
- gangliotetraosylceramide
Gal3GalNAc4Gal4GlcCer
- GM1
Gal3GalNAc4(NeuAc3)Gal4GlcCer
- RBC
red blood cells
- BSA
bovine serum albumin
- PBS
phosphate-buffered saline
- SDS
sodium dodecyl sulfate
- TLC
thin-layer chromatography
- HPLC
high pressure liquid chromatography
- MS
mass spectrometry
- FAB
fast-atom bombardment
- EI
electron impact 相似文献
9.
-Glucans were prepared from Agaricus blazei Murill by repeated extraction with hot water. The average molecular weights of -glucans were 30–50 kDa by gel filtration chromatography. Oligosaccharides (AO), derived from hydrolyzing -glucans with an endo--(16)-glucanase from Bacillus megaterium, were mainly di- and tri-saccharides. Though -glucans and AO both showed anti-hyperglycemic, anti-hypertriglyceridemic, anti-hypercholesterolemic, and anti-arteriosclerotic activity indicating overall anti-diabetic activity in diabetic rats, AO had about twice the activity of -glucans with respect to anti-diabetic activity. 相似文献
10.
E. S. Kalyaeva I. S. Sever V. G. Nikiforov O. N. Danilevskaya 《Molecular & general genetics : MGG》1980,178(3):669-674
Summary As has been shown previously, RNA polymerase subunit ts-mutation rpoC1 results in an overproduction of RNA polymerase subunits at nonpermissive temperature. The mutant enzyme shows low activity in vitro and a sedimentation coefficient 9S which is characteristic of immature core polymerase. In this paper we describe a mutation designated opr1 which suppresses RNA polymerase subunit overproduction. The mutation was found among Ts+ revertants of the Ts double mutant carrying a rpoC1 mutation and a rif-r rpo B251 mutation. Opr1 is closely linked to the original rpo mutations and shows complete trans-dominance. Although opr1 seems to affect RNA polymerase, it does not suppress the accumulation of immature 9S RNA polymerase and does not restore the activity of the RpoC1 mutant enzyme. This and other results of a comparison of strains carrying different combinations of rpoC1, rpoB251 and opr1 mutations suggest that neither inhibition of total RNA and protein synthesis, nor the low RNA polymerase activity in vitro, nor the apparent defects in enzyme maturation, nor the enzyme degradation observed at 42°C are responsible for the overproduction in RpoC1 strains. 相似文献