scholarly journals Evidence for N-linked glycosylation in Toxoplasma gondii

1993 ◽  
Vol 291 (3) ◽  
pp. 713-721 ◽  
Author(s):  
M Odenthal-Schnittler ◽  
S Tomavo ◽  
D Becker ◽  
J F Dubremetz ◽  
R T Schwarz
Keyword(s):  
Toxoplasma Gondii ◽  
Gel Filtration ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Surface Glycoprotein ◽  
Common Precursor ◽  
The Common ◽  
Oligosaccharide Structures

In this paper we report experiments demonstrating the presence of N-linked oligosaccharide structures in Toxoplasma gondii tachyzoites, providing the first direct biochemical evidence that this sporozoan parasite is capable of synthesizing N-linked glycans. The tachyzoite surface glycoprotein gp23 was metabolically labelled with [3H]glucosamine and [3H]mannose. Gel-filtration chromatography on Bio-Gel P4 columns produced four radiolabelled N-linked glycopeptides which were sensitive to peptidase-N-glycanase F, but resistant to endoglycosidases H and F. Using chemical analysis and exoglycosidase digestions followed by Dionex-high-pH anion-exchange chromatography and size fractionation on Bio-Gel P4 we show that gp23 has N-linked glycans in the hybrid- or complex-type structure composed of N-acetylgalactosamine, N-acetylglucosamine and mannose and devoid of sialic acid and fucose residues. In addition, the sensitivity of glycopeptides from glycoprotein extracts to endoglycosidases H and F revealed the in vivo synthesis of oligomannose-type structures by T. gondii tachyzoites. We have extended these findings by demonstrating the ability of T. gondii microsomes to synthesize in vitro a glucosylated lipid-bound high-mannose structure (Glc3Man9GlcNAc2) that is assumed to be identical with the common precursor for N-glycosylation in eukaryotes.

scholarly journals A Novel Hemagglutinin with Antiproliferative Activity against Tumor Cells from the Hallucinogenic MushroomBoletus speciosus

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Jian Sun ◽  
Tzi-Bun Ng ◽  
Hexiang Wang ◽  
Guoqing Zhang
Keyword(s):  
Cation Exchange ◽  
Antiproliferative Activity ◽  
Gel Filtration ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Lymphocytic Leukemia ◽  
Hemagglutinating Activity ◽  
Cation Exchange Chromatography ◽  
Type Ab

Little was known about bioactive compounds from the hallucinogenic mushroomBoletus speciosus. In the present study, a hemagglutinin (BSH,B. speciosushemagglutinin) was isolated from its fruiting bodies and enzymatic properties were also tested. The chromatographic procedure utilized comprised anion exchange chromatography on Q-Sepharose, cation exchange chromatography on CM-Cellulose, cation exchange chromatography on SP-Sepharose, and gel filtration by FPLC on Superdex 75. The hemagglutinin was a homodimer which was estimated to be approximately 31 kDa in size. The activity of BSH was stable up to 60°C, while there was a precipitous drop in activity when the temperature was elevated to 70°C. BSH retained 25% hemagglutinating activity when exposed to 100 mM NaOH and 25 mM HCl. The activity was potently inhibited by 1.25 mM Hg2+and slightly inhibited by Fe2+, Ca2+, and Pb2+. None of the sugars tested showed inhibition towards BSH. Its hemagglutinating activity towards human erythrocytes type A, type B, and type AB was higher than type O. The hemagglutinin showed antiproliferative activity towards hepatoma Hep G2 cells and mouse lymphocytic leukemia cells (L1210)in vitro, with IC50of 4.7 μM and 7.0 μM, respectively. It also exhibited HIV-1 reverse transcriptase inhibitory activity with an IC50of 7.1 μM.

In vivo behaviour of rat transferrin bearing a hybrid glycan and its interaction with macrophages

1992 ◽  
Vol 70 (8) ◽  
pp. 636-642 ◽  
Author(s):  
Wei-Li Hu ◽  
Paul A. Chindemi ◽  
Erwin Regoeczi
Keyword(s):  
Bone Marrow ◽  
Principal Component ◽  
Anion Exchange Chromatography ◽  
Sialic Acid Residue ◽  
Exchange Chromatography ◽  
Lectin Affinity Chromatography ◽  
Human Transferrin ◽  
Excess Iron

Production of rat transferrin containing a single hybrid glycan was induced by treating rats with swainsonine, an inhibitor of α-mannosidase II. The principal component of this variant transferrin containing one sialic acid residue per mole of protein was separated from other forms of transferrin by anion-exchange chromatography, followed by lectin affinity chromatography. Transferrin bearing the hybrid glycan was degraded in vivo with a half-life of 14 h as compared with 40 h for transferrin containing a standard diantennary glycan. By using 125I-labelled tyramine-cellobiose, a label whose discharge from lysosomes is strongly retarded, organs rich in reticuloendothelial elements (liver, bone marrow, lungs, and spleen) were identified as the major sites of catabolism of the transferrin variant. The liver took up more 59Fe from the variant (26% of the dose in 90 min) than from control rat transferrin (12%). The excess iron uptake was reduced by the intravenous injection of either human transferrin or ovalbumin, and it was abolished by administering both. Macrophages from bone marrow and lungs degraded the transferrin variant in vitro. The degradation was significantly enhanced when transferrin receptors were blocked by human transferrin, and it was significantly reduced by ovalbumin and methyl glucopyranoside.Key words: glycoprotein, iron metabolism, lectin, plasma protein metabolism, transferrin.

scholarly journals Brain peptides and glial growth. II. Identification of cells that secrete glia-promoting factors.

1986 ◽  
Vol 102 (3) ◽  
pp. 812-820 ◽  
Author(s):  
D Giulian ◽  
D G Young
Keyword(s):  
Nervous System ◽  
High Performance ◽  
Gel Filtration ◽  
Anion Exchange Chromatography ◽  
Brain Cell ◽  
Exchange Chromatography ◽  
Secretory Cells ◽  
Brain Peptides ◽  
The Central Nervous System

Glia-promoting factors (GPFs) are brain peptides which stimulate growth of specific macroglial populations in vitro. To identify the cellular sources of GPFs, we examined enriched brain cell cultures and cell lines derived from the nervous system for the production of growth factors. Ameboid microglia secreted astroglia-stimulating peptides, while growing neurons were the best source of the oligodendroglia-stimulating factors. These secretion products co-purified by gel filtration, anion exchange chromatography, and reverse-phase high performance liquid chromatography with GPFs isolated from goldfish and rat brain. Our findings suggest that glial growth in the central nervous system is regulated in part by a signaled release of peptides from specific secretory cells.

scholarly journals Yeast Pab1 interacts with Rna15 and participates in the control of the poly(A) tail length in vitro.

1997 ◽  
Vol 17 (7) ◽  
pp. 3694-3701 ◽  
Author(s):  
N Amrani ◽  
M Minet ◽  
M Le Gouar ◽  
F Lacroute ◽  
F Wyers
Keyword(s):  
Wild Type Strain ◽  
Tail Length ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Wild Type ◽  
Cleavage And Polyadenylation ◽  
Two Hybrid ◽  
Polyadenylation Factor

In Saccharomyces cerevisiae, the single poly(A) binding protein, Pab1, is the major ribonucleoprotein associated with the poly(A) tails of mRNAs in both the nucleus and the cytoplasm. We found that Pab1 interacts with Rna15 in two-hybrid assays and in coimmunoprecipitation experiments. Overexpression of PAB1 partially but specifically suppressed the rna15-2 mutation in vivo. RNA15 codes for a component of the cleavage and polyadenylation factor CF I, one of the four factors needed for pre-mRNA 3'-end processing. We show that Pab1 and CF I copurify in anion-exchange chromatography. These data suggest that Pab1 is physically associated with CF I. Extracts from a thermosensitive pab1 mutant and from a wild-type strain immunoneutralized for Pab1 showed normal cleavage activity but a large increase in poly(A) tail length. A normal tail length was restored by adding recombinant Pab1 to the mutant extract. The longer poly(A) tails were not due to an inhibition of exonuclease activities. Pab1 has previously been implicated in the regulation of translation initiation and in cytoplasmic mRNA stability. Our data indicate that Pab1 is also a part of the 3'-end RNA-processing complex and thus participates in the control of the poly(A) tail lengths during the polyadenylation reaction.

Isolation of Somatostatin (a Somatotropin Release Inhibiting Factor) of Ovine Hypothalamic Origin

1974 ◽  
Vol 52 (11) ◽  
pp. 1067-1072 ◽  
Author(s):  
P. Brazeau ◽  
W. Vale ◽  
R. Burgus ◽  
R. Guillemin
Keyword(s):  
Growth Hormone ◽  
Amino Acid ◽  
Gel Filtration ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Partition Chromatography ◽  
Inhibiting Factor ◽  
Layer Chromatography

Isolation of somatostatin, a tetradecapeptide of ovine origin inhibiting somatotropin secretion, is reported. About 490 000 hypothalamic fragments were submitted to alcohol–chloroform extraction, countercurrent distribution, ion-exchange chromatography, gel filtration, and partition chromatography. Of the 8.5 mg material thus obtained, 77% was accounted for by a peptide shown homogeneous by electrophoresis, thin-layer chromatography, and amino acid analysis. The peptide inhibits the secretion of radioimmunoassayable growth hormone at doses of ≥ 1.0 nM in vitro and 400 ng per rate in vivo.

Purification of 3 monomeric monocot mannose-binding lectins and their evaluation for antipoxviral activity: potential applications in multiple viral diseases caused by enveloped viruses

2007 ◽  
Vol 85 (1) ◽  
pp. 88-95 ◽  
Author(s):  
Amandeep Kaur ◽  
Sukhdev Singh Kamboj ◽  
Jatinder Singh ◽  
Rajinder Singh ◽  
Melissa Abrahams ◽  
...  
Keyword(s):  
Cell Line ◽  
High Performance ◽  
Human Cancer ◽  
Gel Filtration ◽  
Cancer Cell Line ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Gloriosa Superba ◽  
African Green Monkey Kidney

Three monomeric monocot lectins from Zephyranthes carinata, Zephyranthes candida, and Gloriosa superba with carbohydrate specificity towards mannose derivatives and (or) oligomannose have been isolated and purified from their storage tissues. The lectins were purified by anion-exchange chromatography on DEAE–Sephacyl and by gel filtration chromatography on Biogel P-200 followed by high-performance liquid chromatography. The purified lectins, Z. carinata, Z. candida, and G. superba had molecular masses of 12, 11.5, and 12.5 kDa, respectively, as determined by gel filtration and SDS–PAGE, indicating that they are monomers. In a hapten inhibition assay, methyl-α-d-mannopyranoside inhibited agglutination of both Z. candida and Z. carinata; the latter was also inhibited by Man(α1-2)Man and Man(α1-3)Man. Gloriosa superba showed inhibition only with Man(α1-4)Man of all of the sugars and glycoproteins tested. All purified lectins agglutinated red blood cells from rabbit, whereas G. superba was also reactive towards erythrocytes from guinea pig. All of the lectins were nonglycosylated and did not require metal ions for their activity. They were labile above 60 °C and were affected by denaturing agents such as urea, thiourea, and guanidine–HCl. The lectins were virtually nonmitogenic, like other members of Amaryllidaceae and Liliaceae. Of the 3 lectins, G. superba was found to be highly toxic to the BSC-1 cell line (African green monkey kidney epithelial cells), while both of the Zephyranthes species showed significant in vitro inhibition of poxvirus replication in BSC-1 cells without any toxic effects to the cells. In addition, Z. candida also exhibited significant anticancer activity against SNB-78, a CNS human cancer cell line.

scholarly journals Purification and properties of a phytate-degrading enzyme produced by Enterobacter sakazakii ASUIA279

2012 ◽  
Vol 3 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Abd El Aziem Farouk ◽  
Ralf Greiner ◽  
Anis Shobirin Meor Hussin
Keyword(s):  
Relative Rate ◽  
Gel Filtration ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Enterobacter Sakazakii ◽  
Degrading Enzyme ◽  
Purification And Properties ◽  
Sds Page ◽  
Rate Of Hydrolysis

An extracellular phytate-degrading enzyme produced by Enterobacter sakazakii ASUIA279 was purified to homogeneity using FPLC anion exchange chromatography and gel filtration. The enzyme was purified about 66-fold with a recovery of 27%. Its molecular mass was estimated to be 43 kDa by SDS-PAGE. The Michaelis constant (KM) and turnover number (kcat ) for sodium phytate at pH 5.0 and 50°C were calculated from the Lineweaver-Burk plot to be 760 µM and 4.14s-1, respectively. The enzyme showed narrow substrate specificity and not phytate, but GTP was dephosphorylated with the highest relative rate of hydrolysis. However, according to the kcat/KM values, phytate was concluded to be the in vivo substrate of the enzyme. Optimal activity was determined at pH 4.5 and 45-55°C. The enzyme was strongly inhibited by Fe3+, Cu2+, Zn2+, molybdate, vanadate, fluoride and phosphate (1 mM).

scholarly journals Evidence for Contribution of Tripartite Hemolysin BL, Phosphatidylcholine-Preferring Phospholipase C, and Collagenase to Virulence of Bacillus cereus Endophthalmitis

2000 ◽  
Vol 68 (9) ◽  
pp. 5269-5276 ◽  
Author(s):  
Douglas J. Beecher ◽  
Timothy W. Olsen ◽  
Eileen B. Somers ◽  
Amy C. L. Wong
Keyword(s):  
Bacillus Cereus ◽  
Phospholipase C ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Bacterial Cells ◽  
Retinal Tissue ◽  
Toxic Concentrations ◽  
Hemolysin Bl

ABSTRACT Bacillus cereus causes a highly fulminant endophthalmitis which usually results in blindness. We previously concluded that hemolysin BL (HBL), a tripartite necrotizing pore-forming toxin, is a probable endophthalmitis virulence factor because it is highly toxic to retinal tissue in vitro and in vivo. We also determined that B. cereus produces additional retinal toxins that might contribute to virulence. Here we fractionated crudeB. cereus culture supernatant by anion-exchange chromatography and found that in vitro retinal toxicity was also associated with phosphatidylcholine-preferring phospholipase C (PC-PLC). The pure enzyme also caused retinal necrosis in vivo. We showed that phosphatidylinositol-specific PLC and sphingomyelinase were nontoxic and that two hemolysins, cereolysin O and a novel hemolysin designated hemolysin IV, were marginally toxic in vitro. The histopathology of experimental septic endophthalmitis in rabbits mimicked the pathology produced by pure HBL, and both HBL and PC-PLC were detected at toxic concentrations in infected vitreous fluid. Bacterial cells were first seen associated with the posterior margin of the lens and eventually were located throughout the lens cortex. Detection of collagenase in the vitreous humor suggested that infiltration was facilitated by the breakdown of the protective collagen lens capsule by that enzyme. This work supports our conclusion that HBL contributes to B. cereus virulence and implicates PC-PLC and collagenase as additional virulence factors.

scholarly journals New Amylase Inhibitor Present in Corn Seeds Active In Vitro Against Amylase from Fusarium verticillioides

Plant Disease ◽  
2003 ◽  
Vol 87 (3) ◽  
pp. 233-240 ◽  
Author(s):  
Edson L. Z. Figueira ◽  
Alejandro Blanco-Labra ◽  
Antônio Carlos Gerage ◽  
Elisabete Y. S. Ono ◽  
Elizabeth Mendiola-Olaya ◽  
...  
Keyword(s):  
High Performance ◽  
Fusarium Verticillioides ◽  
Gel Filtration ◽  
Anion Exchange Chromatography ◽  
Human Saliva ◽  
Exchange Chromatography ◽  
Experimental Conditions ◽  
Amylase Inhibitor ◽  
Fusarium Sp

A screening for specific amylase inhibitor levels against amylase from Fusarium verticillioides (Fusarium moniliforme), the most relevant mycotoxigenic fungus in corn, was conducted on 37 corn hybrids. The amylase inhibitor levels in these hybrids ranged from 5.5 to 16.0 amylase inhibitor units per gram of corn (AIU/g) in the MASTER and AG5011 hybrids, respectively. The hybrid with the maximum content of inhibitor was used as the source of this new protein. The inhibitor was partially purified using fractional precipitation, gel filtration on Sephadex G-75 column, high performance liquid chromatography (HPLC) Superose HR 10/30 column, and HPLC anion exchange chromatography, obtaining a 20.7-fold purification. Electrophoresis after denaturing and heating under reductive conditions showed an apparent 23.8 kDa molecular mass and an acidic isoelectric point of 5.4, which differs from previous molecular masses reported for other inhibitors present in corn seeds (14 and 22 kDa). This inhibitor showed activity against amylases from human saliva and pancreas, from the fungi F. verticillioides and Aspergillus flavus, and from the insects Acanthoscelides obtectus, Zabrotes subfasciatus, Tribolium castaneum, and Sitotroga cerealella. The mycoflora found in the corn grain indicated Fusarium sp. as the most prevalent fungi (81.1% of the samples), with a count ranging from 1.5 × 102 to 2.4 × 106 CFU/g of corn. The presence of fumonisins was detected in 21 out of the 37 hybrids studied, ranging from 0.05 to 2.67 μg of FB per gram of corn. No correlation could be established between this amylase inhibitor level in the corn seeds and the presence of Fusarium sp. or with the fumonisin content under the experimental conditions of the test.

Synthesis of peptides by the solid-phase method. V. Substance P and analogs

1980 ◽  
Vol 58 (4) ◽  
pp. 272-280 ◽  
Author(s):  
A. Fournier ◽  
R. Couture ◽  
J. Magnan ◽  
M. Gendreau ◽  
D. Regoli ◽  
...  
Keyword(s):  
Substance P ◽  
Solid Phase ◽  
Gel Filtration ◽  
Paper Electrophoresis ◽  
Exchange Chromatography ◽  
Phase Method ◽  
Elemental Analyses ◽  
Solid Phase Method

We have synthesized a series of 12 analogs of the undecapeptide substance P in order to perform a structure–activity study of this peptide. In the present work, each residue was substituted by L-alanine, and the C-terminal amide was replaced by the free carboxyl in order to pinpoint biologically important side chains and functional groups. The synthesis of the analogs was carried out by the automatic solid-phase method. Couplings were performed by the symmetrical anhydride procedure. After cleavage with liquid HF, the peptides were purified by gel filtration and ion-exchange chromatography. Their purity was assessed by thin-layer chromatography, paper electrophoresis, amino acid and elemental analyses, and high pressure liquid chromatography. They were tested for biological activity in vitro on the ileum of the guinea pig, the mesenteric vein of the rabbit, and the vas deferens of the rat, and in vivo by measuring their effect on the blood pressure of the rat.

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