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  • 1
    Keywords: PEPTIDE ; human ; DISEASE ; SITE ; SITES ; PROTEIN ; SAMPLE ; SAMPLES ; SERA ; INDUCTION ; BINDING ; treatment ; ACID ; IDENTIFICATION ; SUBUNIT ; DIFFERENCE ; MOBILITY ; GAS ; ACUTE LYMPHOBLASTIC-LEUKEMIA ; IONIZATION ; ACETYLATED SIALIC ACIDS ; sialic acid ; VISCERAL LEISHMANIASIS ; C-REACTIVE PROTEIN ; acute-phase protein ; BINDING CHARACTERISTICS ; CATLA-CATLA ; CHROMATOGRAPHY ; ELECTROPHORESIS ; FRAGMENTS ; GLUCOSE ; glycosylation ; INDIVIDUALS ; LABEO-ROHITA ; LECTIN ; lectin binding ; LIQUID-CHROMATOGRAPHY ; MAJOR CARP ; matrix-assisted laser-desorption ionization analysis (MALDI analysis) ; molecular modelling ; protein-protein interaction ; PROTEIN-PROTEIN INTERACTIONS ; SIALIC-ACID ; SUBUNITS
    Abstract: As an acute-phase protein, human C-reactive protein (CRP) is clinically important. CRPs were purified from several samples in six different pathological conditions, where their levels ranged from 22 to 342 mug/ml. Small, but significant, variations in electrophoretic mobilities on native PAGE suggested differences in molecular mass, charge and/or shape. Following separation by 9 SDS/PAGE, the), showed single subunits with some differences in their molecular masses ranging between 27 and 30.5 kDa, but for a particular disease, the mobility was the same for CRPs purified from multiple individuals or pooled sera. Isoelectric focusing (IEF) also indicated that the purified CRPs differed from each other. Glycosylation was demonstrated in these purified CRPs by Digoxigenin kits, neuraminidase treatment and binding with lectins. The presence of N-linked sugar moiety was confirmed by N-glycosidase F digestion. The presence of sialic acid, glucose, galactose and mannose has been demonstrated by gas liquid chromatography, mass spectroscopic and fluorimetric analysis. Matrix-assisted laser-desorption ionization analysis of the tryptic digests of three CRPs showed systematic absence of two peptide fragments, one at the N-terminus and the other near the C-terminus. Model-building suggested that the loss of these fragments exposed two potential glycosylation sites on a cleft floor keeping the protein-protein interactions in pentraxins and calcium-dependent phosphorylcholine-binding qualitatively unaffected. Thus we have convincingly demonstrated that human CRP is glycosylated in some pathological conditions
    Type of Publication: Journal article published
    PubMed ID: 12693993
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  • 2
    Keywords: CELLS ; CELL ; DIAGNOSIS ; FOLLOW-UP ; TOOL ; DISEASE ; DISTINCT ; cell line ; MOLECULES ; LINES ; PATIENT ; prognosis ; ANTIGEN ; ANTIGENS ; CELL-LINES ; treatment ; MOLECULE ; RECOGNITION ; ACID ; antibodies ; antibody ; IDENTIFICATION ; LYMPHOMA ; CELL-LINE ; leukemia ; LINE ; PURIFICATION ; US ; ACETYLATED SIALIC ACIDS ; ACHATINA-FULICA ; Achatinin-H ; ACID-BINDING LECTIN ; INDIVIDUALS ; SIALIC-ACID ; CHILDREN ; AFFINITY ; MINIMAL RESIDUAL DISEASE ; ACUTE MYELOGENOUS LEUKEMIA ; LEUKEMIC-CELLS ; CHAIN ; CHILDHOOD ; chronic lymphocytic leukemia ; 9-O-acetylated sialoglycoconjugates ; acute lymphoblastic leukemia ; anti-Neu5,9Ac(2) antibody ; CLINICAL STATUS ; INDIAN VISCERAL LEISHMANIASIS ; Neu5,9Ac(2)-binding lectin ; O-ACETYLATION ; SIALOGLYCANS
    Abstract: Sialic acids as terminal residues of oligosaccharide chains play crucial roles in several cellular recognition events. Exploiting the selective affinity of Achatinin-H toward N-acetyl-9-O-acetytneuraminic acid-alpha2-6-GalNAc, we have demonstrated the presence of 9-O-acetylated sialoglycoproteins (Neu5,9Ac(2)-GPs) on lymphoblasts of 70 children with acute lymphoblastic leukemia (ALL) and on leukemic cell lines by fluorimetric HPLC and flow cytometric analysis. This study aims to assess the structural aspect of the glycotope of Neu5,9Ac(2)-GPS(ALL) and to evaluate whether these disease-specific molecules can be used to monitor the clinical outcome of ALL. The Neu5,9Ac(2)-GPs(ALL) were affinity-purified, and three distinct leukemia-specific molecular determinants (135, 120, and 90 kDa) were demonstrated by SDS-PAGE, western blotting, and isoelectric focusing. The carbohydrate epitope of Neu5,9Ac(2)-GPs(ALL) was confirmed by using synthetic sialic acid analogs. The enhanced presence of anti-Neu5,9Ac(2)-GP(ALL) antibody in ALL patients prompted us to develop an antigen-ELISA using purified Neu5,9Ac(2)-GPs(ALL) as coating antigens. Purified antigen was able to detect leukemia-specific antibodies at presentation of disease, which gradually decreased with treatment. Longitudinal monitoring of 18 patients revealed that in the early phase of the treatment patients with lower anti-Neu5,9Ac(2)-GPs showed a better prognosis. Minimal cross-reactivity was observed in other hematological disorders (n = 50) like chronic myeloid leukemia, acute myelogenous leukemia, chronic lymphocytic leukemia, and non-Hodgkin's lymphoma as well as normal healthy individuals (n=21). This study demonstrated the potential of purified Neu5,9Ac(2)-GPs(ALL) as an alternate tool for detection of anti-Neu5,9Ac(2)-GP antibodies to be helpful for diagnosis and monitoring of childhood ALL patients
    Type of Publication: Journal article published
    PubMed ID: 15190007
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  • 3
    Keywords: ACTIVATED PROTEIN-KINASE ; INDUCED APOPTOSIS ; ACUTE LYMPHOBLASTIC-LEUKEMIA ; LYMPHOCYTES ; acetylation ; ROLES ; SIALIC ACIDS ; ganglioside GD3 ; SIALATE-O-ACETYLTRANSFERASE ; HUMAN T
    Abstract: Gangliosides play important roles in the development, differentiation and proliferation of mammalian cells. They bind to other cell membrane components through their terminal sialic acids. Different gangliosides influence cellular functions based on the positions and linkages of sialic acids. Expression of gangliosides mainly depends on the status of sialic acid-modulatory enzymes, such as different types of sialyltransferases and sialidases. One such sialyltransferase, disialoganglioside GD3 synthase, is specifically responsible for the production of GD3. Pancreatic ductal adenocarcinoma, making up more than 90% of pancreatic cancers, is a fatal malignancy with poor prognosis. Despite higher sialylation status, the disialoganglioside GD3 level is very low in this cancer. However, the exact status and function of this disialoganglioside is still unknown. Here, we intended to study the intracellular mechanism of disialoganglioside GD3-induced apoptosis and its correlation with the adhesion and angiogenic pathways in pancreatic cancer. We demonstrated that disialoganglioside GD3 synthase-transfected cells showed enhanced apoptosis and it caused the arrest of these cells in the S-phase of the cell cycle. Integrins, a family of transmembrane proteins play important role in cell-cell recognition, invasion, adhesion and migration. disialoganglioside GD3 co-localised with integrin-beta1 and thereby inhibited it's downstream signalling in transfected cells. Transfected cells exhibited inhibition of cell adhesion with extracellular matrix proteins. Enhanced GD3 expression down regulated angiogenesis-regulatory proteins and inhibited epidermal growth factor/vascular endothelial growth factor-driven angiogenic cell growth in these cells. Taken together, our study provides support for the GD3-induced cell cycle arrest, disruption of integrin-beta1-mediated anchorage, inhibition of angiogenesis and thereby induced apoptosis in pancreatic cancer cells.
    Type of Publication: Journal article published
    PubMed ID: 24842107
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  • 4
    Abstract: Endoplasmic reticulum (ER) stress results from protein unfolding/misfolding during cellular maturation, which requires a coordinated action of several chaperones and enzymes and Ca(2+) signalling. ER-stress possibly has a positive effect on survival of pancreatic cancer cell. Therefore, detailed insights into this complex signaling network are urgently needed. Here, we systematically analyzed the impact of ER stress-mediated unfolded protein response (UPR) and Ca(2+)-signaling cross-talk for the survival of pancreatic adenocarcinoma (PDAC) cells. We observed enhanced ER activity and initiation of UPR signaling induced by a carbazole alkaloid (mahanine). This event triggers a time-dependent increase of intracellular Ca(2+) leakage from ER and subsequently Ca(2+) signaling induced by enhanced reactive oxygen species (ROS) produced by this pro-oxidant agent. In addition, we observed an altered glycosylation, in particular with regard to reduced linkage-specific sialic acids possibly due to decreased sialyltransferase activity. Changes in sialylation entailed enhanced expression of the ganglioside GD3 in the treated cells. GD3, an inducer of apoptosis, inhibited pancreatic xenograft tumor. Taken together, our study describes a molecular scenario how PDAC cells are driven into apoptosis by mahanine by UPR-driven ER stress-associated and ROS-mediated calcium signaling and possibly defective sialylation.
    Type of Publication: Journal article published
    PubMed ID: 29500369
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  • 5
    Keywords: human ; PROTEIN ; INDUCTION ; C-REACTIVE PROTEIN
    Type of Publication: Journal article published
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 46 (1990), S. 433-441 
    ISSN: 1420-9071
    Keywords: Sialic acid ; lectin ; sialoglycoconjugate ; cell surface ; antibody ; invertebrate lectin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The literature contains several reviews on lectins in general, covering mainly those from plants and invertebrates. However, the sialic acid binding lectins have not been reviewed so far. Considering the importance of sialic acids in cell sociology, lectins which specifically recognize terminal sialic acid residues are potentially useful as analytical tools in studying the biological functions of sialoglycoconjugates. These lectins, along with monoclonal antibodies raised against sialoglycoconjugates, have been used in the detection, affinity purification, cytochemical localization and quantitation of such glycoconjugates. In this review the main emphasis has been placed on the occurrence, general purification procedures, macromolecular properties, sugar specificities and applications of these lectins.
    Type of Medium: Electronic Resource
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  • 7
    Abstract: Sialic acids have a pivotal functional impact in many biological interactions such as virus attachment, cellular adhesion, regulation of proliferation, and apoptosis. A common modification of sialic acids is O-acetylation. O-Acetylated sialic acids occur in bacteria and parasites and are also receptor determinants for a number of viruses. Moreover, they have important functions in embryogenesis, development, and immunological processes. O-Acetylated sialic acids represent cancer markers, as shown for acute lymphoblastic leukemia, and they are known to play significant roles in the regulation of ganglioside-mediated apoptosis. Expression of O-acetylated sialoglycans is regulated by sialic acid-specific O-acetyltransferases and O-acetylesterases. Recent developments in the identification of the enigmatic sialic acid-specific O-acetyltransferase are discussed.
    Type of Publication: Journal article epub ahead of print
    PubMed ID: 22371169
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  • 8
    Keywords: ACUTE LYMPHOBLASTIC-LEUKEMIA ; DE-ORTHO-ACETYLATION ; ESCHERICHIA-COLI K1 ; MURINE ERYTHROLEUKEMIA-CELLS ; MOUSE HEPATITIS-VIRUS ; INFLUENZA-C-VIRUS ; GROUP-B STREPTOCOCCUS ; HEMAGGLUTINATING ENCEPHALOMYELITIS VIRUS ; LEISHMANIA-DONOVANI PROMASTIGOTES ; RECEPTOR-DESTROYING ENZYME
    Abstract: Sialic acids have a pivotal functional impact in many biological interactions such as virus attachment, cellular adhesion, regulation of proliferation, and apoptosis. A common modification of sialic acids is O-acetylation. O-Acetylated sialic acids occur in bacteria and parasites and are also receptor determinants for a number of viruses. Moreover, they have important functions in embryogenesis, development, and immunological processes. O-Acetylated sialic acids represent cancer markers, as shown for acute lymphoblastic leukemia, and they are known to play significant roles in the regulation of ganglioside-mediated apoptosis. Expression of O-acetylated sialoglycans is regulated by sialic acid-specific O-acetyltransferases and O-acetylesterases. Recent developments in the identification of the enigmatic sialic acid-specific O-acetyltransferase are discussed.
    Type of Publication: Journal article published
    PubMed ID: 22371169
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  • 9
    Keywords: CELLS ; GENE ; COMPONENTS ; SERA ; BINDING ; culture ; RECOGNITION ; antibodies ; IDENTIFICATION ; ACUTE LYMPHOBLASTIC-LEUKEMIA ; SURFACE ; ACETYLATED SIALIC ACIDS ; ACHATINA-FULICA ; Achatinin-H ; ACID-BINDING LECTIN ; INFLUENZA-C VIRUS ; Leishmania donovani ; LINKED OLIGOSACCHARIDES ; O-acetylated sialic acid ; sialic acid ; TRANS-SIALIDASE ; TRYPANOSOMA-CRUZI ; UDP-GIcNAc2-epimerase ; VISCERAL LEISHMANIASIS
    Abstract: Sialic acids as terminal residues of oligosaccharide chains play a crucial role in several cellular recognition events. The presence of sialic acid on promastigotes of Leishmania donovani, the causative organism of Indian visceral leishmaniasis, was demonstrated by fluorimetric high- performance liquid chromatography showing Neu5Ac and, to a minor extent, Neu5,9Ac(2). The presence of Neu5Ac was confirmed by GC/MS analysis. Furthermore, binding with sialic acid- binding lectins Sambucus nigra agglutinin (SNA), Maackia amurensis agglutinin (MAA), and Siglecs showed the presence of both alpha2,3- and alpha2,6-linked sialic acids. No endogenous biosynthetic machinery for Neu5Ac could be demonstrated in the parasite. Concomitant western blotting of parasite membranes and culture medium with SNA demonstrated the presence of common sialoglyconjugates (123, 90, and 70 kDa). Similarly, binding of MAA with parasite membrane and culture medium showed three analogous sialoglycans corresponding to 130, 117, and 70 kDa, indicating that alpha2,3- and alpha2,6-linked sialoglycans are adsorbed from the fetal calf serum present in the culture medium. L. donovani promastigotes also reacted with Achatinin- H, a lectin that preferentially identifies 9-O-cetylated sialic acid in alpha2--〉6 GalNAc linkage. This determinant was evidenced on parasite cell surfaces by cell agglutination, ELISA, and flow cytometry, where its binding was abolished by pretreatment of cells with a recombinant 9-O-acetylesterase derived from the HE1 region of the influenza C esterase gene. Additionally, binding of CD60b, a 9-O-acetyl GD3-specific monoclonal antibody, corroborated the presence of terminal 9-O- acetylated disialoglycans. Our results indicate that sialic acids (alpha2--〉6 and alpha2--〉3 linked) and 9-O-acetyl derivatives constitute components of the parasite cell surface
    Type of Publication: Journal article published
    PubMed ID: 12626423
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  • 10
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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