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221.
222.
Rosalita M Smagula Herman Van Halbeek Jean M Decker Andrew V Muchmore Charles E Moody Anne P Sherblom 《Glycoconjugate journal》1990,7(6):609-624
The urinary glycoprotein uromodulin (Tamm-Horsfall glycoprotein) exhibits a pregnancy-associated ability to inhibit antigen-specific T cell proliferation, and the activity is associated with a carbohydrate moiety [Muchmore and Decker (1985) Science 229:479–81; Hessionet al., (1987) Science 237:1479–84; Muchmore, Shifrin and Decker (1987) J Immunol 138:2547–53]. We report here that the Man6(7)GlcNAc2-R glycopeptides derived from uromodulin inhibit antigen-specific T cell proliferation by 50% at 0.2–2 M, and further studies, reported elsewhere, confirm that oligomannose glycopeptides from other sources are also inhibitory, with Man9GlcNAc2-R the most inhibitory of those tested [Muchmoreet al., J Leukocyte Biol (in press)]. In this work, we have extended the observation of pregnancy-associated inhibitory activity to a second species, and have compared the oligomannose profile of Tamm-Horsfall glycoprotein (nonpregnant) with that of uromodulin (pregnant) derived from both human and bovine sources. Surprisingly, there was a pregnancy-associated decrease in the total content of oligomannose chains due predominantly to a reduction in Man5GlcNAc2-R and Man6GlcNAc2-R. Man7GlcNAc2-R, which did not decrease with pregnancy, comprised a significantly greater proportion of the total oligomannose chains in pregnant vs. nonpregnant samples from both species (human; 34.6% vs. 25.9%: bovine; 14.4% vs. 7.2%). 相似文献
223.
224.
225.
Large fragments of nef-protein and gp110 envelope glycoprotein from HIV-1. Synthesis, CD analysis and immunoreactivity 总被引:1,自引:0,他引:1
J M Sabatier G Fontan E Loret K Mabrouk H Rochat J C Gluckman L Montagnier C Granier E Bahraoui J Van Rietschoten 《International journal of peptide and protein research》1990,35(1):63-72
Chemical synthesis of large peptide fragments (from 18 to 66 amino acid residues long) of the gp110 envelope glycoprotein and of nef-protein from HIV-1 was achieved by the solid phase method. Stepwise assembling of the peptide chains was carried out automatically on 4-(oxymethyl)-phenylacetamidomethyl resin using the N-alpha-butyloxycarbonyl amino acids with benzyl-based side chain protecting groups. Two elongation protocols were used depending on the peptide chain length: a standard cycle, mainly characterized by a single coupling step (Boc-amino acid symmetrical anhydride in dimethylformamide), and an optimized one for large peptides, based on a double coupling strategy (Boc-amino acid symmetrical anhydride first in dimethylformamide, then in dichloromethane). Final cleavage of the peptide from the solid support was carried out by anhydrous hydrogen fluoride and crude peptides were purified by C18 reverse phase medium pressure liquid chromatography after molecular filtration. Characterization of the purified peptides was done by analytical HPLC, amino acid content determination, and circular dichroism analysis both in polar (H2O) and in non-polar (TFE) environments. Immunoreactivity of anti-nef positive sera from HIV-1 infected patients by ELISA with the synthetic peptides was investigated. The results showed four major antigenic regions of nef-protein and mainly the immunodominance of the N- and C-termini of the molecule. Several of these peptides should prove to be useful for both diagnosis and vaccination purposes. 相似文献
226.
Enumeration and presumptive identification of some functional groups of bacteria in the rumen of dairy cows fed grass silage-based diets 总被引:5,自引:0,他引:5
Abstract Samples of rumen ingesta from two rumen-fistulated dairy cows fed grass silage-based diets were examined for numbers and types of bacteria that developed colonies on rumen fluid-agar media designated to support the growth of (a) a wide range of species, (b) cellulolytic bacteria, (c) lactate-fermenting bacteria, (d) non-fermentative bacteria. The most numerous species was Bacteroides ruminicola followed by Butyrivibrio fibrisolvens . The most abundant cellulolytic species were Eubacterium cellulosolvens and Ruminococcus flavefaciens. Megasphaera elsdenii and Selenomonas ruminantium were important lactate fermenters but an unidentified bacterium that grew poorly on maintenance medium was by far the most numerous among bacteria isolated from lactate-containing medium. One strain remained sufficiently viable to show that it fermented lactate to propionate and acetate. 相似文献
227.
Pelargonium otaviense
Knuth andP. spinosum
Willd. are excluded from sect.Glaucophyllum, whileP. grandiflorum (Andr.)Willd.,P. patulum
Jacq. andP. tabulare (Burm. f.)L'Hérit. of sect.Eumorpha are included. Sect.Glaucophyllum is characterized by green to glaucous vegetative organs and zygomorphic white to pink corolla with five narrow petals. All the species have an identical pollen and chromosome morphology, the same basic chromosome number (x = 11) and similar flavonoid patterns. A close relationship between sect.Glaucophyllum and sect.Pelargonium is indicated by the occurrence of natural hybrids and concordant characters. Isorhamnetin and luteolin have been detected in the genus for the first time. 相似文献
228.
Morley S. Muralitharan Reinhard F. M. Van Steveninck Stephen E Chandler 《Plant cell reports》1990,9(3):151-155
Non-selected and sodium chloride selected callus lines of Vacdnium corymbosum L.cv Blue Crop and cv. Denise Blue were grown on media supplemented with 0–100 mM NaCl. For both cultivars, fresh weight and dry weight yields were greater in selected lines on all levels of NaCl. Selected lines of Blue Crop displayed better growth than selected lines of Denise Blue at most concentrations of NaCl. Internal Na+ and Cl– concentrations in selected and non-selected lines of both cultivars increased as external concentration was raised. However, selected lines of Blue Crop and Denise Blue accumulated more Na+ and Cl– than non-selected lines. Selected lines of both cultivars maintained higher levels of K+ than non-selected lines on all external NaCl levels. Selected lines of Blue Crop had higher levels of Na+ and Cl– than that of Denise Blue. The results suggest Na+ and Cl– accumulation could be a mechanism allowing better growth in selected lines at moderate salinity levels (50–75 mM NaCl). 相似文献
229.
P Stinissen W Van Hul G Van Camp H Backhovens A Wehnert A Vandenberghe C Van Broeckhoven 《Genomics》1990,7(1):119-122
The DNA marker locus D21S13, localized in the 21q11.1-q21 region, has been closely linked to familial Alzheimer's disease. We constructed a physical map of 1.7 Mb around D21S13 using probes pGSM21 and pGSE9. The results indicated that pGSM21 contains recognition sites for at least three rare-cutting restriction enzymes. The clustering of rare-cutting restriction sites is indicative of the presence of an HTF (HpaII tiny fragment) island. Restriction site mapping and methylation analysis proved that pGSM21 contains a methylation-free HTF island. Furthermore, a cDNA correlate has been isolated confirming that pGSM21 is part of an expressed sequence. Today, the gene associated with pGSM21 is the gene closest to the centromere on the 21q arm. 相似文献
230.
D Lundell C Lunn R Greenberg J Fossetta S Narula R Kastelein A Van Kimmenade 《Biotechnology and applied biochemistry》1990,12(5):567-578
The bacterial membrane serves both as a cell organelle and as a barrier for segregating the metabolically active cytoplasm from the extracellular milieu. Thus we can use plasmid vectors designed to produce a hybrid protein containing an efficient signal peptide coupled to the amino terminus of the cloned heterologous protein (secretion cloning vectors) for the production of proteins which are insoluble, proteolytically sensitive, or bacteriocidal when produced in the cytoplasm of Escherichia coli. We demonstrate that human granulocyte-macrophage colony stimulating factor can be isolated as an active species only after transport into the bacterial periplasm. Production of the protein in the bacterial cytoplasm is bacteriocidal. We also demonstrate that biologically active human interleukin 4 appears only after transport of the protein into the bacterial growth medium. The protein forms membrane-associated aggregates in the cytoplasm, and demonstrates an active but nonnative conformation when expressed in the periplasm. This may correlate with the affinity of the interleukin 4 molecule for negatively charged macromolecules, including bacterial membrane components and bacterial lipopolysaccharides, which may alter the folding pathway inside the cell. 相似文献