Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “NEURAMINIDASE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMed1990

Photoaffinity labeling of the lysosomal neuraminidase from bovine testis.

ASA-NeuAc2en, a photoreactive arylazide derivative of sialic acid, is shown to be a powerful competitive inhibitor of lysosomal neuraminidase from bovine testis (Ki approximately 21 microM). Photoaffinity labeling and partial purification of preparations containing this lysosomal neuraminidase activity result in specifically and non-specifically labeled polypeptides. Only labeling in a 55 kDa polypeptide is found to be specific, since it could be prevented by the competitive neuraminidase inhibitor NeuAc2en. We conclude that the 55 kDa polypeptide in the bovine testis beta-galactosidase/neuraminidase/protective protein complex contains the catalytic site of neuraminidase.

Affinity Labels↗
PubMed1983

A rapid and sensitive assay for neuraminidase using peanut lectin hemagglutination: application to Vibrio cholera and Trypanosoma cruzi.

A neuraminidase assay based on peanut lectin agglutination is described. Human red blood cells are used both as substrate for the enzyme and as probe for the lectin. The validity of the method is ascertained by measuring the enzyme and lectin activities on erythrocytes whose outer membrane sialic acid was labeled with tritium after oxidation with sodium periodate followed by reduction with sodium borotritiide. The neuraminidases of Trypanosoma cruzi and Vibrio cholera are used as examples; in both cases, a linear relationship is observed between the degree of erythrocyte desialylation and the peanut hemagglutination titer. For the hemagglutination assay, lectin in homogeneous form as well as in crude peanut extracts may be used, and free sialic acid need not be separated from substrate-bound sialic acid. The hemagglutinating activity of peanut lectin is not affected by pre-treatment of the erythrocytes with various proteases. The method is particularly useful in the neuraminidase analysis of multiple samples, such as in gel filtration chromatography and for screening of hybridoma antibodies against neuraminidase.

Chromatography, Gel↗
PubMed1982

Neuraminidase activities in sialidosis and mucolipidosis.

Defects of neuraminidase activities towards sialyloligosaccharides in fibroblasts and leucocytes and enhanced excretion of sialyloligosaccharides in urine were shown in patients with adult type sialidosis with partial deficiency of beta-galactosidase and cherry red spot-myoclonus syndrome. No differences in their neuraminidase residual levels and urinary excretion patterns on thin-layer chromatography were found between these two disorders. In mucolipidosis II and III patients, the neuraminidase activities towards sialyloligosaccharides were almost normal in leucocytes, although decreased in fibroblasts. The discrepancy of neuraminidase activities towards 2 leads to 3 and 2 leads to 6 sialyloligosaccharide isomers was not noticed in all cases.

Chromatography, Thin Layer↗
PubMed1984

Sequence of the neuraminidase gene of an avian influenza A virus (A/parrot/ulster/73, H7N1).

The complete sequence of the neuraminidase (NA) gene of the influenza A strain A/parrot/ Ulster /73 ( H7N1 ) has been determined after reverse transcribing and cloning it into the pBR322 plasmid, followed by subcloning into M13 vectors and sequencing with dideoxynucleotide chain terminators. The gene consists of 1458 nucleotides and codes for a protein of 469 amino acids. The neuraminidase has seven potential glycosylation sites. According to the molecular weight as determined by electrophoretic migration in polyacrylamide gel all of these sites might carry a carbohydrate side chain. When the parrot Ulster NA was compared with two other N1 neuraminidases, those of the human PR8 and WSN strains, deletions in the stalk region of 15 amino acids for PR8 NA and of 16 amino acids for WSN NA were apparent. No further rearrangements were found within N1 neuraminidases. Although the parrot Ulster strain was isolated 40 years after the two human strains, the base sequence homology of their NA genes is still 83 or 82%, respectively.

Allantoin↗
PubMed1984

Influenza virus neuraminidase with hemagglutinin activity.

Isolated intact influenza virus neuraminidase (NA) molecules of the N9 subtype have been found to possess hemagglutinin (HA) activity which, at equivalent protein concentration, was fourfold higher than that of isolated hemagglutinin molecules of the H3 subtype. The amino-terminal sequence of the N9 NA is the same as in neuraminidases of the eight other influenza A virus NA subtypes previously reported. Viruses possessing N9 NA therefore have two different HA activities and antibody to either HA or NA alone was incapable of inhibiting hemagglutination by the virus. However, antibody to the HA of an H1N9 virus neutralized its infectivity as effectively as it neutralized H1N1 or H1N2 viruses whose neuraminidases have no HA activity. (Antibodies to N9 NA did not neutralize the infectivity of viruses with N9 neuraminidase). 2-deoxy-2,3-dehydro-N-acetyl-neuraminic acid inhibited N9 NA activity but had no effect on the HA activity of the isolated N9 NA. One interpretation of this result would be that the HA and NA activities are located in separate sites. Pronase-released N9 NA heads form crystals suitable for X-ray diffraction studies and preliminary data to 2.9 A establish the space group as cubic, I432 with cell dimension a = 184 A. Data extend to beyond 1.9 A resolution, and these will be collected in the future.

Animals↗
PubMed1989

Avian cells expressing the Newcastle disease virus hemagglutinin-neuraminidase protein are resistant to Newcastle disease virus infection.

The cDNA derived from the Newcastle disease virus (NDV) hemagglutinin-neuraminidase (HN) gene was inserted into a replication-competent Schmidt-Ruppin Rous sarcoma virus-derived vector. Chick embryo cells transfected with this vector expressed HN-sized protein which could be precipitated with anti-HN antibody. These cells adsorbed avian red blood cells and the cell surfaces exhibited neuraminidase activity while cells transfected with an antisense version of the gene were negative for hemadsorption and neuraminidase. The cells transfected with the retroviral vector containing the HN gene were resistant to infection by NDV and influenza virus, viruses which bind to sialic acid containing receptors, but sensitive to vesicular stomatitis virus (VSV). Cells transfected with the antisense version of the HN gene were sensitive to NDV, influenza virus, and VSV infection. Thus the HN protein-expressing cells are likely resistant to NDV and influenza virus due to the destruction of the cellular receptors by the neuraminidase of the HN protein. The expression of the influenza virus HA protein using the same retrovirus vector has been reported previously (L. A. Hunt, D. W. Brown, H. L. Robinson, C. W. Naeve, and R. G. Webster, 1988, J. Virol. 62, 3014-3019). Cells infected with this vector were sensitive to infection with influenza virus, NDV, and VSV. Thus expression of a viral surface protein does not necessarily confer resistance of the cell to the homologous virus.

Animals↗
PubMed1990

Antigenic, sequence, and crystal variation in influenza B neuraminidase.

The neuraminidase (NA) genes of influenza B viruses B/Maryland/59, B/Hong Kong/8/73, B/Singapore/222/79, B/Oregon/5/80, B/USSR/100/83, B/Victoria/3/85, B/Leningrad/179/86, B/Memphis/6/86, and B/Memphis/3/89 have been sequenced. The deduced amino acid sequences show high variability in the stalk domain of the NA, but a surprising degree of sequence conservation in the head region which carries all the antigenic and enzyme activity. The variable region coding for the neuraminidase stalk also translates into a variable section in the overlapping NB polypeptide, which is coded from a second reading frame that overlaps the first 100 amino acids of NA. The influenza B NAs are antigenically distinguishable with monoclonal antibodies in neuraminidase-inhibition tests, even when there is only one amino acid sequence difference. However, seven of nine escape mutants selected with monoclonal antibodies were distinguished only by the antibody used for selection. When NA heads of influenza B viruses are crystallized, there are remarkable differences in crystal morphology between neuraminidases which have very few sequence changes.

Amino Acid Sequence↗
PubMed1992

Expression of cDNA encoding the Sendai virus hemagglutinin-neuraminidase gene: characterization of wild-type and mutant gene products.

Cloned cDNA encoding the Sendai virus (SV) hemagglutinin-neuraminidase (HN) envelope glycoprotein was expressed in cultured cells in two ways: (I) infection with HN-expressing recombinant vaccinia virus, or (II) transfection with a plasmid with T7 promoter and termination sequences flanking the HN gene, with intracellular T7 RNA polymerase supplied by coinfection with recombinant vaccinia virus that expresses the enzyme. The HN expressed was indistinguishable from the authentic SV protein in antigenicity, cell surface location, and formation of oligomeric structures. In addition, HN expressed from cDNA functioned normally in both hemadsorption and neuraminidase activities. The usefulness of cDNA expression for analyzing HN structure and function was evaluated by mutating the HN cDNA and observing the consequences for HN protein activity. Since previous work indicated that the lysine residue at position 461 is important for the neuraminidase activity of HN, we used site-directed mutation to produce HN protein with this lysine residue changed to glutamic acid. The mutated HN had neuraminidase activity with significantly increased thermal stability, indicating that residue 461 may be essential to the protein's conformation.

Antigens, Surface↗
PubMed1985

Effect of neuraminidase treatment on the expression of Fc IgG receptors on chicken embryonic bursa and thymus cells.

Bursa and thymus cells from chicken embryos at different ages were analyzed for Fc IgG receptors by EA-rosette technique and by binding of heat aggregated chicken IgG (agg IgG) in the indirect immunofluorescence test. Neuraminidase treatment resulted in a substantial increase of agg IgG binding cells both in the embryonic bursa and thymus. The binding of agg IgG was shown to be specific for Fc IgG receptors, since IgM and F(ab')2 fragments were not bound to neuraminidase-treated embryonic cells. A far lower percentage of EA-rosette-forming cells than agg IgG binding cells were found both in untreated and neuraminidase-treated bursa and thymus cells. It was concluded that neuraminidase can reveal additional Fc IgG receptor sites mainly for agg IgG on embryonic thymus and bursa cells.

Animals↗
PubMed1991

Modulation of the secondary antibody response of murine lymphocytes to sheep red blood cells in vitro by neuraminidase and exoglycosidases.

The effect of digestion of lymphocytes with neuraminidase and exoglycosidases on the secondary antibody response in vitro to sheep red blood cell (SRBC) antigen was tested. Treatment of spleen cells from SRBC-primed mice with 3 micrograms/ml of neuraminidase slightly but significantly augmented their plaque-forming cell response to SRBC, whereas treatment with 100 micrograms/ml of a mixture of exoglycosidases did not. Rather unexpectedly, however, treatment of the spleen cells with the mixture of both neuraminidase and exoglycosidases greatly augmented the response. This enzyme action was substrate specific inasmuch it was ablated by addition of mucin as a neuraminidase inhibitor to the enzyme mixture. The target of the enzyme activity was not glass-adherent macrophages, but was glass-non-adherent suppressor cells in the antigen-primed cell population. Evidence was provided that the phenotype of suppressor cells whose activity was ablated by the enzyme treatment was Thy-1+. It is suggested from these results that sialylated complex type oligosaccharides on antigen-primed T cells play a critical role in their suppressor activity.

Animals↗
PubMed1992

Distinct hemagglutinin and neuraminidase epitopes involved in antigenic variation of recent human parainfluenza virus type 2 isolates.

A panel of fourteen neutralizing anti-HN monoclonal antibodies (mAbs) to the prototype Greer strain of human parainfluenza virus type 2 (PI2) was used to determine the extent of antigenic variation in recent virus isolates. Competitive binding analysis with the mAbs indicated the presence of at least five distinct antigenic sites (I to V) on the HN glycoprotein molecule. MAbs recognizing different antigenic sites were found to be associated with the hemagglutinin (sites I, IV and V), hemagglutinin and neuraminidase (site II), or neuraminidase (site III) activities. The location of two distinct epitopes identifying the neuraminidase sites (II and III) was further verified from the generation of escape mutants. Antibodies directed to sites I and III failed to show any detectable binding or neutralizing activity against a number of natural PI2 virus isolates collected in Texas between 1986 and 1987. Interestingly, these natural variants, unlike the prototype virus, did not show any detectable neuraminidase activity with fetuin as a substrate and the enzyme activity was only detected with N-acetylneuramin-lactose as an alternative substrate. Despite the observed variation in the antigenic sites, primary infection with the prototype virus or the natural variants generated a protective immune response against challenge infection with the other virus strains.

Animals↗
PubMed1995

Purified influenza A virus N2 neuraminidase vaccine is immunogenic and non-toxic in humans.

The immunogenicity and toxicity of a purified influenza virus (N2) neuraminidase vaccine (NAV) were investigated in 88 human subjects aged 18-40, and compared to response to a conventional trivalent influenza vaccine, Fluogen (Parke-Davis). NAV doses ranged from 2.6 to 69.9 micrograms and were given intramuscularly. Serologic neuraminidase-inhibiting (NI) and neuraminidase-specific ELISA responses in this N2-primed population were roughly proportional to the dose administered. Maximal response was seen in 14-21 days and NI antibody titers persisted unabated for the 6-month post-vaccination follow-up period. All doses were well tolerated with respect to local and systemic reactions. NI tests performed with the putative (1975) priming N2 antigen demonstrated anamnestic response but did not reveal responses not already shown with the homologous (1992) antigen. Response to this purified, non-adjuvanted preparation encourages continuing investigation of the induction of infection-permissive immunity with influenza virus neuraminidase.

Adolescent↗
PubMed1977

Effect of acute ethanolic intoxication on the neuraminidase activity of rat liver Golgi apparatus.

Neuraminidase and galactosyltransferase were investigated in total Golgi appartus and in the three fractions of increasing densities (GF1, GF2, and GF3) isolated from the microsomal fraction of rat liver homogenates by flotation in a discontinuous sucrose density gradient (Ehrenreich, J.H., Bergeron, J.J.M., Siekevitz, P. and Palade, G.E. (1973) J. Cell Biol. 59, 45-72). About 50% decreases in neuraminidase content (units/g liver) and specific activity (units/mg protein) were observed in total Golgi as well as in the three fractions isolated at 45 min, 90 min, 180 min and 16 h after administration of a single oral dose of 50% aqueous ethanol (0.6 g/100 g body weight). Colchicine administration (introperitoneal injection, 0.5 mg/100 g body weight) caused a similar loss of neuraminidase activity; however, the effect of ethanol plus colchicine was not additive. Golgi galactosyltransferase, on the other hand, experienced marked increases of activity following ethanol administration but, unlike the results reported by others (Gang, H., Lieber, C.S. and Rubin, E. (1973) Nat. New Biol. 243, 123-125), significant increases in total activity and specific activity were already quite evident at 90 min after ethanol ingestion. In contrast with the decreased values observed in Golgi, the total particle-bound neuraminidase was significantly elevated following ethanol administration. Ultrastructural studies revealed increased lysosomal content and detachment of polysomes from the rough endoplasmic reticulum. A model, which takes into account these enzymological and ultrastructural findings and their biological significance, is proposed.

Animals↗
PubMed1983

Decreased ganglioside neuraminidase activity in fibroblasts from mucopolysaccharidosis patients. Inhibition of the activity in vitro by sulfated glycosaminoglycans and other compounds.

The neuraminidase activities towards the ganglioside substrates GD1a, GD3 and GM3 were found to be markedly diminished in homogenates of fibroblasts cultured from patients with various genetic mucopolysaccharidoses. Mixing normal and patients' fibroblast homogenates revealed this effect to be due to the presence of diffusible inhibitors. The neuraminidase acting on the trisaccharide sialyllactose, on the other hand, showed normal activity in all the cell lines tested. Experiments in vitro revealed the sulfated glycosaminoglycans chondroitin 4-sulfate and heparin, the polysaccharide dextran sulfate, and the trypanocidal drug suramin to be strongly inhibitory on the ganglioside GD1a neuraminidase activity of normal fibroblast homogenates. Regarding chondroitin 4-sulfate, this inhibition was of the non-competitive type. A disulfated tetrasaccharide prepared from chondroitin 4-sulfate, on the other hand, was not at all inhibitory. These and additional findings led us to propose a model for the interaction between enzyme and inhibitor, involving a 'clamping' mechanism by the polysulfated compounds. We conclude that the decreased ganglioside neuraminidase activities of mucopolysaccharidosis fibroblasts are due to an inhibition by the accumulated sulfated glycosaminoglycans and that such inhibition is responsible for the storage of certain gangliosides in the tissues of the patients.

Gangliosides↗
PubMed1984

Solubilization, stabilization and isoelectric focusing of human liver neuraminidase activity.

Homogenate preparations of human liver have been prepared and over 75% of the particulate neuraminidase activity (which comprises approx. 90% of the total activity) has been solubilized using 0.85% (w/v) Triton X-100 in 25 mM phosphate buffer (pH 6.8). The solubilized neuraminidase activity is extremely labile, but can be stabilized for at least 4 weeks at 2-4 degrees C, using 10 mM N-acetylneuraminic acid. Kinetic characterization of homogenate and solubilized supernatant fluid neuraminidase activities indicated comparable pH optimum curves (maximum activity at pH 4.5-4.7) and apparent Km values (0.2-0.4 mM) for the synthetic fluorometric substrate 4-methylumbelliferyl-alpha-D-N-acetylneuraminic acid. Isoelectric focusing has been performed on human liver homogenates and Triton X-100-solubilized neuraminidase activities, and the presence of several forms (4-6) with isoelectric points (pI values) between 4.4 and 5.2 has been demonstrated in both preparations. The similar kinetic and isoelectric focusing properties of the two preparations suggest that the solubilized enzyme activity is representative of the homogenate activity and that the solubilized enzyme is suitable for purification purposes.

Adolescent↗
PubMed1988

Comparative efficacy of pneumococcal neuraminidase and pneumolysin as immunogens protective against Streptococcus pneumoniae.

Neuraminidase and pneumolysin were purified from cultures of Streptococcus pneumoniae and used, either singly or in combination, to immunize juvenile mice which were subsequently challenged intranasally with virulent S. pneumoniae. In each of two independent trials, a small but significant (P less than 0.05) increase in survival time (compared with that of non-immunized mice) was observed in groups which had been immunized with neuraminidase, but only if the enzyme had been pre-treated with 3.4% (v/v) formaldehyde. The median extension in survival time was significantly less (P less than 0.01) than that of mice which had been immunized with pneumolysin alone. The median survival time for mice which had received both formaldehyde-treated neuraminidase and pneumolysin was not significantly different from that of mice which had received pneumolysin alone. While these findings provide direct evidence that neuraminidase contributes to the pathogenicity of the pneumococcus in mice, they suggest that this protein may be of less value than pneumolysin as a vaccine component in the present experimental model.

Animals↗
PubMed2004

In vitro generation and characterisation of an influenza B variant with reduced sensitivity to neuraminidase inhibitors.

A contemporary influenza type B virus was passaged in vitro in the presence of increasing concentrations of the neuraminidase inhibitors, zanamivir and oseltamivir carboxylate (0.1-1000 microM over nine passages). After the fifth passage in the presence of zanamivir (10 microM), the virus acquired a Glu 119 Asp neuraminidase mutation (influenza A N2 subtype numbering) in the enzyme active site. After a further three passages, in which growth occurred in 100 microM of zanamivir, a Gln 218 Lys mutation (A (H3) numbering) in the HA1 domain of the haemagglutinin was found. In a fluorescence-based neuraminidase inhibition assay, viruses with the Glu 119 Asp NA mutation had a 32,000-fold reduction in sensitivity to the NA inhibitor zanamivir compared to the wild-type virus, while the mutation resulted in a 105-fold reduction in sensitivity to oseltamivir carboxylate. Viruses grown in the presence of 1000 microM oseltamivir carboxylate did not acquire any neuraminidase mutations but did have a His 103 Gln substitution (A (H3) numbering) in the HA1 region of the haemagglutinin which was demonstrated to significantly reduce receptor binding strength in vitro. Tissue culture assays demonstrated that the HA mutation caused a seven-fold reduction in sensitivity to oseltamivir carboxylate, and a 90-fold reduction in sensitivity to zanamivir.

Antiviral Agents↗
PubMed2006

Susceptibility of highly pathogenic A(H5N1) avian influenza viruses to the neuraminidase inhibitors and adamantanes.

Since 2003, highly pathogenic A(H5N1) influenza viruses have been the cause of large-scale death in poultry and the subsequent infection and death of over 140 humans. A group of 55 influenza A(H5N1) viruses isolated from various regions of South East Asia between 2004 and 2006 were tested for their susceptibility to the anti-influenza drugs the neuraminidase inhibitors and adamantanes. The majority of strains were found to be fully sensitive to the neuraminidase inhibitors oseltamivir carboxylate, zanamivir and peramivir; however two strains demonstrated increased IC50 values. Sequence analysis of these strains revealed mutations in the normally highly conserved residues 116 and 117 of the N1 neuraminidase. Sequence analysis of the M2 gene showed that all of the A(H5N1) viruses from Vietnam, Malaysia and Cambodia contained mutations (L26I and S31N) associated with resistance to the adamantane drugs (rimantadine and amantadine), while strains from Indonesia were found to be a mix of both adamantane resistant (S31N) and sensitive viruses. None of the A(H5N1) viruses from Myanmar contained mutations known to confer adamantane resistance. These results support the use of neuraminidase inhibitors as the most appropriate class of antiviral drug to prevent or treat human A(H5N1) virus infections.

Acids, Carbocyclic↗