排序方式: 共有22条查询结果,搜索用时 15 毫秒
1.
The role of the carbohydrate residues of fibronectin concerning the specificities of that glycoprotein to interact with fibroblastic cell surfaces, gelatin, and heparin was examined. Tunicamycin was used to produce carbohydrate-depleted fibronectin; it was synthesized by cultured fibroblasts. Unglycosylated and glycosylated fibronectins were analyzed for their ability to bind gelatin and heparin, using affinity columns. Fibronectin-coated surfaces were used to quantitatively measure cell adhesion and spreading. The results showed that the lack of carbohydrates significantly increased the interaction of the protein with gelatin and markedly enhanced its ability to promote adhesion and spreading of fibroblasts. In contrast, the binding of fibronectin to heparin was not influenced by glycosylation. The composite data indicate that the Asn-linked oligosaccharides of fibronectin act as modulators of biological functions of the glycoprotein. 相似文献
2.
3.
Yury V. Matsuka Deborah A. Dilts Susan Hoiseth Rasappa Arumugham 《The protein journal》1998,17(7):719-728
An outer membrane PIA protein fromNeisseria gonorrhoeae strain FA19 was expressed inEscherichia coli and refoldedin vitro in the presence of zwitterionic detergent. Its proper folding and subunit organization was confirmed by comparison with the
native counterpart. The unfolding of PIA has been investigated using fluorescence spectroscopy and analytical size-exclusion
chromatography methods. Analysis of the denaturation pathway of the PIA revealed that it forms an unusually labile quaternary
structure. In the presence of 1 M guanidinium chloride (GdmCl) or upon heating up to 50°C, dissociation of the PIA oligomer
was observed resulting in the formation of folded monomeric intermediates. Unfolding of monomers occurs at 80°C or in the
presence of 4.3 M GdmCl, indicating high intrinsic stability toward both GdmCl and elevated temperatures. Both oligomeric
and monomeric forms of PIA exhibited affinity to the hydrophobic probe 1-anilinonaphthalene-8-sulfonic acid (ANS) and bind
withK
d=80 and 130 μM, respectively. Denaturation of the PIA completely abolished affinity to ANS, suggesting that hydrophobicity
is a property of the folded state of the porin. 相似文献
4.
Arumugham Raghunathan Harley R. Ferguson Jr. Carole J. Bornarth Wanmin Song Mark Driscoll Roger S. Lasken 《Applied microbiology》2005,71(6):3342-3347
Genomic DNA was amplified about 5 billion-fold from single, flow-sorted bacterial cells by the multiple displacement amplification (MDA) reaction, using 29 DNA polymerase. A 662-bp segment of the 16S rRNA gene could be accurately sequenced from the amplified DNA. MDA methods enable new strategies for studying nonculturable microorganisms. 相似文献
5.
A presolubilization procedure with the use of glycerol is shown to be applicable for the structural analysis of polysaccharides. Neutral, acidic, high-molecular-weight and low-molecular-weight polysaccharides were solubilized in glycerol prior to methylation and subsequent linkage analysis by GC-MS. All four types of polysaccharides showed significant increases in derivatization following presolubilization as measured by recovery of partially methylated alditol acetates. 相似文献
6.
Swainsonine inhibits macrophage receptor-mediated uptake and degradation of a mannosyl-oligosaccharide 总被引:1,自引:0,他引:1
Rat pulmonary macrophages were incubated in the presence of a radiolabeled mannosyl-oligosaccharide obtained from ovalbumin. Receptor-mediated endocytosis and degradation of this ligand by the cells was followed in the presence or absence of swainsonine, an inhibitor of alpha-mannosidases. The results indicated that at higher concentrations (greater than 1 microgram/ml) of swainsonine, both the internalization and degradation of the radiolabeled ligand were inhibited. At a concentration of 0.1 microgram/ml of swainsonine, only the degradation was inhibited while the uptake was unaltered. The degradation of the oligosaccharide was blocked due to the inhibition of lysosomal alpha-mannosidase. However, the inhibition of lysosomal alpha-mannosidase was reversible upon withdrawal of swainsonine. 相似文献
7.
Elangovan Elamathi Palaniyandi Malathi Rasappa Viswanathan Amalraj Ramesh Sundar 《Journal of plant biochemistry and biotechnology.》2018,27(3):351-361
Present study was aimed to select a suitable Trichoderma isolate as candidate antagonist based on its efficacy in producing cell wall degrading enzymes (CWDEs), its mycoparasitism activity and expression of related genes against the red rot pathogen caused by Colletotrichum falcatum in sugarcane. For which, six different isolates of Trichoderma selected from our earlier studies (T. harzianum, T. asperullum) were evaluated based on their capability in releasing cell wall degrading enzymes individually and during antagonism with C. falcatum in dual plate. Amongst T. harzianum (T20) exhibited the greatest mycoparasitic potential against the C. falcatum, by producing higher concentration of CWDEs viz., chitinase and β-1, 3-glucanase, slightly lower amounts of cellulase and protease with significant reduction in polygalacturonase produced by pathogen. Further microscopic observation on interaction of C. falcatum with the selected isolate of T. harzianum (T20) exhibited the mycoparasitic activity of antagonist over pathogen in dual culture and inhibition of C. falcatum pathogenesis in detached sugarcane leaves. In addition, expression pattern of eight genes coding various enzymes involved in mycoparasitism by T. harzianum over C. falcatum were analyzed using qRT-PCR in vitro and on sugarcane leaves. In in vitro interactions, five genes of cell wall degrading enzymes viz., chitinase (chit33), endochitinase (endo42), β-1, 3-glucanase (glu), exochitinase 1 (exc1), exochitinase 2 (exc2), were upregulated during and after contact as compared to before contact, while three genes related with proteases such as alkaline proteinase (prb1), trypsin-like protease (Pra1), subtilin-like serine protease (ssp), genes were upregulated during the contact with C. falcatum and slightly down regulated after contact. In detached leaves, seven genes were potentially upregulated except subtilin-like serine protease, which was down regulated during interaction of C. falcatum and T. harzianum as compared to T. harzianum inoculation alone. All these biochemical and molecular results confirm the efficacy of T. harzianum (T20) against C. falcatum and justify the right selection of candidate antagonist for our further studies on identification of antifungal genes/proteins against C. falcatum in sugarcane. 相似文献
8.
Michael J. Fiske Ross A. Fredenburg Karl R. VanDerMeid John C. McMichael Rasappa Arumugham 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2001,753(2)
The UspA2 protein from the bacterium Moraxella catarrhalis is a potential vaccine candidate for preventing human diseases caused by this organism. Before a vaccine can be administered parentally, the level of endotoxin must be reduced as much as possible. However, in this case the endotoxin was very tightly complexed with the UspA2 protein and could not be dissociated with Triton X-100. It was found that it dissociated from the protein with the zwitterionic detergents Zwittergent 3-12 and Zwittergent 3-14. The endotoxin could then be separated from the protein by either ion-exchange or gel filtration chromatography. Using the limulus amoebocyte lysate assay for quantitation, the endotoxin was reduced approximately 20 000-fold. The removal of residual endotoxin from UspA2 preparations had no detrimental effect on the immunological properties of the protein. Mouse antisera raised against UspA2 prior to, and following endotoxin reduction exhibited comparable antibody and bactericidal titers against the tested strains. Further, mice immunized with both preparations, followed by pulmonary challenge with either a homologous or a heterologous isolate, exhibited comparable levels of clearance. 相似文献
9.
Structures of the asparagine-linked sugar chains of laminin 总被引:13,自引:0,他引:13
This investigation describes the isolation and characterization of oligosaccharides of the basement membrane glycoprotein, laminin. Pronase-released glycopeptides of isolated laminin, from a mouse Engelbreth-Holm-Swarm tumor, were fractionated using a combination of gel permeation chromatography and Con A-Sepharose affinity chromatography. The glycopeptides were analyzed for sugar linkage patterns by methylation analysis. Glycopeptides and hydrazine-released oligosaccharides were further analyzed using endo-beta-galactosidase, endo-beta-N-acetylglucosaminidase H and specific exoglycosidases in conjunction with calibrated gel permeation chromatography. Based on these experiments, murine tumor laminin was shown to contain asparagine-linked oligosaccharides with the following structures: bi-, tri- and tetraantennary complex-type oligosaccharides; polylactosaminyl side chains containing Gal(beta 1----4)GlcNAc(beta 1----3) repeating units attached to the trimannose core portion of the bi-, tri- and tetraantennary complex-type oligosaccharides; unusual complex-type oligosaccharides terminated at the nonreducing end with sialic acid, alpha-galactose, beta-galactose and beta-N-acetylglucosamine; alpha-galactosyl residues linked to N-acetyllactosamine sequences; high-mannose-type oligosaccharides. These results, in conjunction with analytical data, indicate that most of the carbohydrate of this laminin is N-linked to asparagine and that there are about 43 such N-linked oligosaccharides per laminin molecule. 相似文献
10.
Yury V. Matsuka Deborah A. Dilts Susan Hoiseth Rasappa Arumugham 《Journal of Protein Chemistry》1998,17(7):719-728
An outer membrane PIA protein fromNeisseria gonorrhoeae strain FA19 was expressed inEscherichia coli and refoldedin vitro in the presence of zwitterionic detergent. Its proper folding and subunit organization was confirmed by comparison with the
native counterpart. The unfolding of PIA has been investigated using fluorescence spectroscopy and analytical size-exclusion
chromatography methods. Analysis of the denaturation pathway of the PIA revealed that it forms an unusually labile quaternary
structure. In the presence of 1 M guanidinium chloride (GdmCl) or upon heating up to 50°C, dissociation of the PIA oligomer
was observed resulting in the formation of folded monomeric intermediates. Unfolding of monomers occurs at 80°C or in the
presence of 4.3 M GdmCl, indicating high intrinsic stability toward both GdmCl and elevated temperatures. Both oligomeric
and monomeric forms of PIA exhibited affinity to the hydrophobic probe 1-anilinonaphthalene-8-sulfonic acid (ANS) and bind
withK
d=80 and 130 μM, respectively. Denaturation of the PIA completely abolished affinity to ANS, suggesting that hydrophobicity
is a property of the folded state of the porin. 相似文献