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Results 251 - 300 of 2017
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Crich David D Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA. - - 2006
The formation of sialic acid glycosides with a thiosialic acid derivative, diphenyl sulfoxide, and trifluoromethanesulfonic anhydride is reported. With an excess of diphenyl sulfoxide, glycal formation can be completely suppressed and excellent yields are obtained for coupling to a wide range of primary, secondary, and tertiary acceptors.
Okazaki Toshio - - 2006
To clarify the regulatory mechanism of the rapid changes in the hemocyte density in the silkworm, Bombyx mori, during ecdysis, we evaluated the relationship between the hemocyte density and the incidence of apoptosis during this stage. We also evaluated the role of the sugar chains on the adhesion of hemocytes ...
Useh N M - - 2006
The erythrocyte surface sialic acid levels of 200 apparently healthy indigenous Nigerian poultry species (pigeons, guinea fowls, ducks and chickens, n = 50 for each species) presented for slaughter at a poultry abattoir in Zaria, Nigeria was determined. Other parameters determined were packed cell volume (PCV) and plasma total protein ...
Natsuki Jun - - 2006
A practical and convenient method for discriminating between the presence and the absence of sialic acid in carbohydrate chains of glycoproteins was devised using paramagnetic beads and two lectins, Sambucus sieboldiana lectin (SSA) and Ricinus communis agglutinin (RCA120). The glycoproteins of transferrin or thyroglobulin were firstly captured to paramagnetic beads ...
Rinninger Andreas - - 2006
Infections by mouse hepatitis viruses result in disease of the liver, the gastrointestinal tract, respiratory tract, and the central nervous system. Coronaviruses related to mouse hepatitis virus express a hemagglutinin-esterase surface glycoprotein, which specifically hydrolyses either 5-N-acetyl-4-O-acetyl neuraminic acid (Neu4,5Ac(2)) or 5-N-acetyl-9-O-acetyl neuraminic acid (Neu5,9Ac(2)). Moreover, these sialic acids represent ...
Wang Junfeng - - 2006
Lectins are known to regulate a wide variety of biological processes. Therefore, small molecule mimics of lectins have the potential to be used as novel diagnostic and therapeutic agents. In our combinatorial search for lectin mimics, we are in need a large number of boronic acids that change fluorescent properties ...
López-Bueno Alberto - - 2006
The role of receptor recognition in the emergence of virulent viruses was investigated in the infection of severe combined immunodeficient (SCID) mice by the apathogenic prototype strain of the parvovirus minute virus of mice (MVMp). Genetic analysis of isolated MVMp viral clones (n = 48) emerging in mice, including lethal ...
Chen Helen Y - - 2006
Sialic acids are sometimes 9-O-acetylated in a developmentally regulated and cell-type-specific manner. Cells naturally expressing the disialoganglioside GD3 often O-acetylate the terminal sialic acid residue, giving 9-O-acetyl-GD3 (9AcGD3), a marker of neural differentiation and malignant transformation. We also reported that Chinese hamster ovary cells transfected with GD3 synthase can spontaneously ...
Hartshorn Kevan L - - 2006
We previously found that scavenger receptor cysteine-rich gp-340 (glycoprotein-340), isolated from lung or saliva, directly inhibits human IAVs (influenza A viruses). We now show that salivary gp-340 has broad antiviral activity against human, equine and porcine IAV strains. Although lung and salivary gp-340 are identical in protein sequence, salivary gp-340 ...
Zeleny Reinhard - - 2006
The long held but challenged view that plants do not synthesize sialic acids was re-evaluated using two different procedures to isolate putative sialic acid containing material from plant tissues and cells. The extracts were reacted with 1,2-diamino-4,5-methylene dioxybenzene and the fluorescently labelled 2-keto sugar acids analysed by reversed phase and ...
Deguchi Kisaburo - - 2006
To investigate the possibility of structural assignment based on negative-ion tandem multistage (MSn) mass spectral matching, four isomers of 2-aminopyridine (PA)-derivatized monosialylated oligosaccharides (i.e., complex-type N-glycans with an alpha2-3- or alpha2-6-linked sialic acid on alpha1-6 or alpha1-3 antennae) were analyzed using high-performance liquid chromatography/electrospray ion trap time-of-flight mass spectrometry (HPLC/ESI-IT-TOFMS). ...
Hara-Yokoyama Miki - - 2006
Gangliosides are glycolipids that contain sialic acid and they are mainly located on the outer leaflet of the cellular plasma membrane of most vertebrate and some invertebrate cells. Because they have structurally diverse, bulky and negatively charged oligosaccharide moieties, gangliosides endow cell membranes with unique molecular characteristics. Although they are ...
Roussel Alain - - 2006
Semliki Forest virus (SFV) is enveloped by a lipid bilayer enclosed within a glycoprotein cage made by glycoproteins E1 and E2. E1 is responsible for inducing membrane fusion, triggered by exposure to the acidic environment of the endosomes. Acidic pH induces E1/E2 dissociation, allowing E1 to interact with the target ...
Babál Pavel - - 2006
Cancer of the thyroid gland is one of the most common endocrine diseases. Histological evaluation is often complicated by difficulty in distinguishing between benign and malignant lesions. Abnormal glycosylation of cell structures, including changes in sialylation, is a feature of the neoplastic transformation process. The aim of this study was ...
Yu Hui - - 2006
Recombinant CMP-sialic acid synthetase, cloned from Streptococcus agalactiae serotype V strain 2603 V/R, is bifunctional having both CMP-sialic acid synthetase and acetylhydrolase (acylesterase) activities. The enzyme is active over a wide pH range with an optimal CMP-sialic acid synthetase activity at pH 9.0 and an optimal acetylhydrolase activity at pH ...
Gopaul Karina P - - 2006
Sialic acid (SA), a terminal monosaccharide of glycoconjugates, has a central role in human biological function. Various point mutations result in the malmetabolism of SA and inherited disorders: Defective SA synthesis causes sialuria and defective SA catabolism causes sialidosis and sialic acid storage disease (SASD). These inborn errors of metabolism ...
Yu Hai H Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, California 95616, - - 2006
Chemoenzymatic synthesis, which combines the flexibility of chemical synthesis and the high selectivity of enzymatic synthesis, is a powerful approach to obtain complex carbohydrates. It is a preferred method for synthesizing sialic acid-containing structures, including those with diverse naturally occurring and non-natural sialic acid forms, different sialyl linkages and different ...
Kronman Chanoch - - 2005
Primates are characterized by a paucity of soluble acetylcholinesterase (AChE) in the circulation at the adult stage, where the predominant circulating cholinesterase is butyrylcholinesterase. In recent years, we subjected recombinant human and bovine acetylcholinesterase to extensive pharmacokinetic studies in mice, an animal system which also displays very low levels of ...
Mann Maretta C - - 2006
The development of sialidase inhibitors is an area of continuing interest due to their potential use as therapeutic agents to combat viral and bacterial infections. Herein, we report our studies involving the sialidase from the pathogen Vibrio cholerae, through the modelling, synthesis and biological evaluation of mimetics of 5-acetamido-2,6-anhydro-3,5-dideoxy-D-glycero-D-galacto-non-2-enonic acid ...
Roy Anita - - 2005
The study was undertaken to determine the sialic acid concentration of cervical tissue and serum of women with healthy and unhealthy cervix. The sialic acid value in local tissue of cervix and in serum showed slight elevation in benign inflammatory lesions, moderate elevation was found in severe dysplasia and preinvasive ...
Corfield A P - - 2005
O-Acetylated sialic acids have been reported in many sialoglycoproteins where they mediate a variety of immune and other biological events. We have previously demonstrated that the protective mucus barrier on the surface of the canine eye contains sialoglycoproteins. We have also investigated the occurrence of O-acetylated sialic acids in these ...
Hao Jijun - - 2005
The most commonly occurring sialic acid, N-acetylneuraminic acid, is the repeating unit in polysialic acid chain of human neuronal cell adhesion molecule as well as in capsular polysialic acid of neuroinvasive bacteria, Escherichia coli K1 and Neisseria meningitidis. Sialic acid synthesis and polymerization occur in slightly different pathways in animals ...
Gaur Deepak - - 2006
The Plasmodium falciparum clone, Dd2, that requires sialic acid for invasion can switch to a sialic acid independent pathway, Dd2(NM). To elucidate the molecular basis of the switch in invasion phenotype of Dd2 to Dd2(NM), we performed expression profiling of the parasites using an oligonucleotide microarray and real-time RT-PCR. We ...
Weiler Rosa M E - - 2006
OBJECTIVE: The aim of this study was to analyze some standard parameters of the unstimulated and stimulated whole saliva of mouth-breathers and a control group to determine if these variables present any difference in mouth-breathers compared to control group, since these parameters of saliva can influence the oral health. METHODS: ...
Streicher Hansjörg - - 2006
A variable synthesis of a new class of sialylmimetics which provides access to pseudo-sialosides containing the successful cyclohexene motif in the sialic acid mimicking part has been developed. The D- and L-xylo cyclohexenephosphonate scaffolds allow attachment of selected aglycons or aglycon mimetics via mixed phosphonate diester strategies and some target ...
Altamore Timothy M - - 2006
The potential of boronic acids to improve the bioavailability of carbohydrate derived drugs was investigated through the study of the transport of four sialic acid derivatives through a lipophilic supported liquid membrane at departure phase pH's of 7.4, 8.5 and 10.0. It was found that facilitated transport did occur in ...
Mikkelsen Trine L - - 2005
The immunomodulatory activities of four sialic acid-containing milk proteins (kappa-casein, glycomacropeptide, lactoferrin, and proteose peptone-3 component) were determined, and the role of sialic acid was evaluated. Two in vitro models were used: murine splenocyte proliferation, where the effect on LPS-, Con A-, and PHA-stimulated proliferation was studied, and cytokine production ...
Post Deborah M B - - 2005
Haemophilus ducreyi, the causative agent of chancroid, produces a lipooligosaccharide (LOS) which terminates in N-acetyllactosamine. This glycoform can be further extended by the addition of a single sialic acid residue to the terminal galactose moiety. H. ducreyi does not synthesize sialic acid, which must be acquired from the host during ...
Catzel Dallia - - 2006
Complex glycoprotein biopharmaceuticals, such as follicle stimulating hormone (FSH), erythropoietin and tissue plasminogen activator consist of a range of charge isoforms due to the extent of sialic acid capping of the glycoprotein glycans. Sialic acid occupies the terminal position on the oligosaccharide chain, masking the penultimate sugar residue, galactose from ...
Bork Kaya - - 2005
Sialic acids are expressed as terminal sugars in many glycoconjugates and play an important role during development and regeneration, as they are involved as polysialic acid in a variety of cell-cell interactions mediated by the neural cell adhesion molecule NCAM. The key enzyme for the biosynthesis of sialic acid is ...
Sakairi Akira - - 2005
The present study thoroughly examined the localization and characterization of glycoconjugates in the secretory epithelium lining the seminal vesicles of the miniature pig, employing light and electron microscopic histochemical procedures, including lectin methods. The present results showed the epithelial cells and luminal secretions to contain glycoconjugates with abundant neutral saccharides ...
Yusuf Sadiq - - 2005
Sialic acids occupy terminal positions on gastric mucus glycoprotein where they contribute to the high viscosity of mucin. Desialylation of mucus may lead to degradation of the mucus and eventually to the breakdown of the gastric mucus barrier. The effect of a variety of damaging agents (0.1 M HCl, 2 ...
Allen Simon - - 2005
Nontypeable Haemophilus influenzae is an opportunistic pathogen and a common cause of otitis media in children and of chronic bronchitis and pneumonia in patients with chronic obstructive pulmonary disease. The lipooligosaccharides, a major component of the outer membrane of H. influenzae, play an important role in microbial virulence and pathogenicity. ...
Zanetta Jean-Pierre - - 2006
A previous study (Bergwerff et al., Biochimie 74 (1992) 25-37) reported that sialic acids present in Asterias rubens gonads were essentially composed of 8-methyl-N-glycolylneuraminic acid (Neu5Gc8Me), a large part of it being acetylated in position 9. Using GC/MS of heptafluorobutyrate derivatives (Zanetta et al., Glycobiology 11 (2001) 663-676) on the ...
Burlak Christopher - - 2005
BACKGROUND: We have previously shown that recognition of human erythrocytes by porcine Kupffer cells is mediated by a carbohydrate-dependent mechanism. The present study explores the possible ligands existing on human glycophorin A and tests their ability to inhibit erythrocyte rosette formation. METHODS: Human erythrocytes were tested for ABO and MN ...
Chrostek Lech - - 2006
BACKGROUND: The normalization of alcohol abuse markers during the abstinence depends on the time since the last drinking. The aim of this study was to evaluate the diagnostic accuracy (area under the curve-AUC, sensitivity and specificity) of CDT, sialic acid and others biochemical and hematological markers of chronic alcohol abuse ...
Sekiya Sadanori - - 2005
While matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is useful in oligosaccharide analysis, the sialic acid, or N-acetylneuraminic acid (NANA), moiety of an oligosaccharide is liable to dissociation in- or postsource during mass measurement. In this study, we tried to stabilize the moiety by amidation, as in the case of peptides ...
Okamura Masashi - - 2005
The present study investigated the involvement of host sialic acids in the erythrocyte infection by two equine Babesia parasites, Babesia equi and Babesia caballi. We observed that the in vitro growth of both parasites is influenced by the removal of sialic acids from the surface of equine erythrocytes (RBC). When ...
Kuroda Yasuhiro - - 2005
Cryoprecipitating IgG3 autoantibodies have been shown to play a significant role in the development of murine lupus-like autoimmune syndrome. However, the structural basis of IgG3 cryoprecipitation still remains to be defined. In view of the implication of positively charged amino acid residues present in variable regions in IgG3 cryoglobulin activity, ...
Arif Saatea - - 2005
BACKGROUND: Cirrhosis liver claims many lives in our country. However early diagnosis carries good prognosis and prevents complications. Estimation of serum sialic acid level may be helpful in the diagnosis of liver cirrhosis and following the dynamics of the disease especially during treatment and follow up to see the prognosis. ...
Girard Christian - - 2005
(-)-Quinic acid was used as a starting material for the preparation of sialyl Lewis(x) mimetics in order to target E-selectin. Spatial orientation of the hydroxyl groups of quinic acid could mimic the l-fucose ones. Introduction of a side chain ending with a carboxylic acid was effected to replace the sialic ...
Shishino Koji - - 2005
BACKGROUND: A convenient method for the measurement of sialic acid in plasma apoB-containing lipoproteins is described. METHODS: Dextran sulphate-Mg(2+) precipitation and enzymatic sialic acid assay were combined and applied to analysis of plasma from 96 healthy controls and 136 hyperlipidaemic subjects of types IIa (n=46), IIb (n=43), and IV (n=47). ...
Chaffin D O - - 2005
Several bacterial pathogens have evolved the means to escape immune detection by mimicking host cell surface carbohydrates that are crucial for self/non-self recognition. Sialic acid, a terminal residue on these carbohydrates, inhibits activation of the alternate pathway of complement by recruiting the immune modulating molecule factors H, I, and iC3b. ...
Hsu Che-Chang - - 2005
An efficient L-3-deoxy-manno-2-octulosonic acid (L-KDO) aldolase was created by directed evolution from the Escherichia coli D-Neu5Ac (N-acetylneuraminic acid, D-sialic acid) aldolase. Five rounds of error-prone PCR and iterative screening were performed with sampling of 10(3) colonies per round. The specificity constant (kcat/Km) of the unnatural sugar L-KDO is improved to ...
Flores-Díaz Marietta - - 2005
Clostridium perfringens phospholipase C (Cp-PLC), also called alpha-toxin, is the major virulence factor in the pathogenesis of gas gangrene. Previously, a cellular UDP-Glc deficiency was related with a hypersensitivity to the cytotoxic effect of Cp-PLC. Because UDP-Glc is required in the synthesis of proteoglycans, N-linked glycoproteins, and glycosphingolipids, the role ...
Lewandrowski Urs - - 2005
Producing detailed mass spectrometric fragmentation data of native oligosaccharides for the purpose of basic structure elucidation has become a readily accessible tool since the availability of enhanced technical equipment. In this report, high-energy collision-induced dissociation (heCID) in combination with MALDI-TOF/TOF technology for analysis of native neutral and acidic oligosaccharides is ...
Williams G J - - 2005
Analogues of N-acetylneuraminic acid (sialic acid, NANA, Neu5Ac), including 6-dipropylcarboxamides, have been found to be selective and potent inhibitors of influenza sialidases. Sialic acid analogues are, however, difficult to synthesize by traditional chemical methods and the enzyme N-acetylneuraminic acid lyase (NAL) has previously been used for the synthesis of a ...
Lakhiari Hamid - - 2005
We developed the synthesis of new supports for the purification of insulin and IgG by affinity chromatography. The preparation of such an affinity support is performed in two steps. First, silica beads are coated with dextran polymers carrying a calculated amount of positively charged diethylaminoethyl groups in order to mask ...
Bardotti Angela - - 2005
The glycoconjugate vaccines against Neisseria meningitidis groups Y and W135 consist of pools of selected oligosaccharides conjugated to the protein carrier (CRM197). Consistent production of these vaccines requires control and thus determination of the average degree of polymerisation of the oligosaccharides used for conjugation. Acid hydrolysis generates group Y and ...
Steenbergen Susan M - - 2005
Pasteurella multocida subsp. multocida is a commensal and opportunistic pathogen of food animals, wildlife, and pets and a zoonotic cause of human infection arising from contacts with these animals. Here, an investigation of multiple serotype A strains demonstrated the occurrence of membrane sialyltransferase. Although P. multocida lacks the genes for ...
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