TY - JOUR. T1 - Deletion mutation in the signal anchor domain activates cleavage of the influenza virus neuraminidase, a type II transmembrane protein. AU - Hogue, B. G.. AU - Nayak, D. P.. PY - 1994. Y1 - 1994. N2 - Influenza virus neuraminidase (NA) is a type II integral membrane protein with a long hydrophobic domain [29 amino acids (aa)] at the N terminus that functions as an uncleaved signal for translocation into the endoplasmic reticulum and anchors the protein in the membrane. The function of the transmembrane domain in intracellular transport was investigated by deletion mutagenesis. Expression of the mutated NA in eukaryotic cells and by in vitro translation in the presence of membranes showed that the deletion of eight amino acids (aa 28 to 35) from the carboxy end of the signal anchor domain resulted in cleavage, probably by the signal peptidase and secretion of NA into the culture medium. The mutant NA (N28-35) was present inside the cell predominantly as dimers, secreted as dimers, ...

Bacterial neuraminidase is type of neuraminidase and a virulence factor for many bacteria including Bacteroides fragilis and Pseudomonas aeruginosa. Its function is to cleave a sialic acid residue off ganglioside-GM1 (a modulator of cell surface and receptor activity) turning it into asialo-GM1 to which type 4 pilli (attachment factors) bind preferentially. Gaskell A, Crennell S, Taylor G (November 1995). The three domains of a bacterial sialidase: a beta-propeller, an immunoglobulin module and a galactose-binding jelly-roll. Structure. 3 (11): 1197-205. doi:10.1016/s0969-2126(01)00255-6. PMID 8591030. Molecular and Cellular Biology ...

We have used a neuraminidase-deficient influenza virus, NWS-Mvi, which was selected by supplying bacterial neuraminidase in the medium (C. Liu and G. M. Air, Virology 194:403-407, 1993), to define the role of neuraminidase in influenza virus replication. Electron microscopy showed that virions of the NWS-Mvi mutant assembled normally and formed large aggregates associated with cell surfaces. The NWS-Mvi virus grown in the absence of neuraminidase was able to carry out a second round of replication in MDCK cells without added neuraminidase, indicating that the virus particles contained in these aggregates were infectious. Aggregates of virus were also found in cytoplasmic vacuoles. When virus-infected cells were incubated in the presence of ferritin, such aggregates were found to be labeled with ferritin, indicating that they are derived from uptake at the cell surface. When the neuraminidase-deficient virus was administered intranasally to C57BL/6 mice, low titers of virus were recovered from ...

Influenza continues to be an ongoing problem despite the existence of vaccines and drugs. Disease outbreaks can occur relatively quickly as witnessed with the recent emergence of the influenza virus A/H1N1 pandemic. The development of new anti-influenza drugs is thus a major challenge. This volume describes all aspects of the virus structure and function relevant to infection. The focus is on drug discovery of inhibitors to the enzyme sialidase, which plays a key role in the infectious lifecycle of the virus. Following an overview of the influenza virus, the haemagglutinin, the interactions with the cell receptors and the enzymology of virus sialidase, recent results in drug design are presented. These include a full coverage of the design, synthesis and evaluation of carbohydrate as well as non-carbohydrate influenza virus sialidase inhibitors. Further reviews of the clinical experience with influenza virus sialidase inhibitors and of the development of resistance to these inhibitor drugs ...

Influenza B Virus Neuraminidase antibody LS-C83326 is an unconjugated mouse monoclonal antibody to influenza virus Influenza B Virus Neuraminidase. Validated for Inhb.

As a member of the wwPDB, the RCSB PDB curates and annotates PDB data according to agreed upon standards. The RCSB PDB also provides a variety of tools and resources. Users can perform simple and advanced searches based on annotations relating to sequence, structure and function. These molecules are visualized, downloaded, and analyzed by users who range from students to specialized scientists.

Neuraminidase inhibitors (NAIs) are vital in managing seasonal and pandemic influenza infections. NAI susceptibilities of virus isolates (n = 5540) collected during the 2008-2009 influenza season were assessed in the chemiluminescent neuraminidase inhibition (NI) assay. Box-and-whisker plot analyses of log-transformed IC(50)s were performed for each virus type/subtype and NAI to identify outliers which were characterized based on a statistical cutoff of IC(50) >3 interquartile ranges (IQR) from the 75(th) percentile. Among 1533 seasonal H1N1 viruses tested, 1431 (93.3%) were outliers for oseltamivir; they all harbored the H275Y mutation in the neuraminidase (NA) and were reported as oseltamivir-resistant. Only 15 (0.7%) of pandemic 2009 H1N1 viruses tested (n = 2259) were resistant to oseltamivir. All influenza A(H3N2) (n = 834) and B (n = 914) viruses were sensitive to oseltamivir, except for one A(H3N2) and one B virus, with D151V and D197E (D198E in N2 numbering) mutations in the NA, ...

Background The sialidase Neu2 is a cytosolic enzyme which is fully expressed in mature muscle myofibers. Methods To investigate Neu2 expression during muscle atrophy, we employed an in vitro model consisting of terminally differentiated C2C12 myotubes exposed to different pro-atrophic stimuli that triggered catabolic pathways involved in proteasome activation or autophagy. Results Neu2 expression was unchanged in myotubes treated with TNF-alpha, a cytokine known to activate the proteasome. However, Neu2 transcript levels and enzymatic activity were downregulated in starved or dexamethasone-treated myotubes that showed proteosomal activation and several hallmarks of macroautophagy, such as formation of autophagosomes, the accumulation of LC3 dots and bulk degradation of long-lived proteins. Neu2 activity and protein levels were rescued upon cotreatment with the lysosomotropic agent NH4Cl, the autophagy inhibitor 3-methyladenine or cathepsin inhibitors, as well as by insulin administration, but ...

1A14: COMPLEX BETWEEN NC10 ANTI-INFLUENZA VIRUS NEURAMINIDASE SINGLE CHAIN ANTIBODY WITH A 5 RESIDUE LINKER AND INFLUENZA VIRUS NEURAMINIDASE

The aim of this project was to characterise a neuraminidase from Streptococcus pneumoniae by relating its amino acid sequence to the enzymatic activity of the protein, leading to the production of mutated neuraminidases that could be tested as protective immunogens. The sequence of the cloned neuraminidase gene (nan A), was compared to other bacterial neuraminidases to identify conserved residues, and also utilising crystallography data, predictions were made of the residues likely to be important in catalysis. Three residues, glutamic acid (E) 647, arginine (R) 663 and tyrosine (Y) 752 were chosen for further study. To assess the importance of these residues in catalysis, conservative substitutions of these residues (E647 > Q, R663 > H and Y752 > F) were made and the subsequent effect of enzyme activity measured. The wild-type and mutated neuraminidase genes were cloned into the expression vector pQE30 and purified by Ni-NTA affinity chromatography. The purified neuraminidases were assayed for ...

Many respiratory pathogens, including Hemophilus influenzae, Streptococcus pneumoniae, and Pseudomonas aeruginosa, express neuraminidases that can cleave α2,3-linked sialic acids from glycoconjugates. As mucosal surfaces are heavily sialylated, neuraminidases have been thought to modify epithelial cells by exposing potential bacterial receptors. However, in contrast to neuraminidase produced by the influenza virus, a role for bacterial neuraminidase in pathogenesis has not yet been clearly established. We constructed a mutant of P. aeruginosa PAO1 by deleting the PA2794 neuraminidase locus (Δ2794) and tested its virulence and immunostimulatory capabilities in a mouse model of infection. Although fully virulent when introduced i.p., the Δ2794 mutant was unable to establish respiratory infection by i.n. inoculation. The inability to colonize the respiratory tract correlated with diminished production of biofilm, as assessed by scanning electron microscopy and in vitro assays. The importance of ...

Recombinant H7N9 Neuraminidase/NA Protein (His36-Leu465) 40108-VNAHC is expressed in HEK293 Cells. With high purity, high biological activity, high stability, and other superior features, you can use this H7N9 Neuraminidase/NA protein for relevant bioassay and related research.

For the treatment of influenza virus infections, neuraminidase inhibitors (NAIs) that prevent the release of virus particles have been effective against most influenza strains. Several neuraminidase (NA) assays are available for the evaluation of NAIs. To understand the NAI functions under physiological conditions, assays mimicking viral particle release should be useful. We have constructed retrovirus-based reporter viruses that are pseudotyped with hemagglutinin (HA) glycoprotein by transfection of producer cells using plasmids expressing retroviral gag-pol, influenza HA, NA, and firefly luciferase genes. Similarly to the life cycle of influenza viruses, the release of pseudotype viruses also requires neuraminidase functions. This requirement was used to develop an assay to evaluate NAI activities by measuring inhibition of pseudotype virus production at different NAI concentrations. The pseudotype virus release assay was used to determine the IC(50) values of Oseltamivir carboxylate, ...

Antiviral drug resistance for influenza therapies remains a concern due to the high prevalence of H1N1 2009 seasonal influenza isolates which display H274Y associated oseltamivir-resistance. Furthermore, the emergence of novel H1N1 raises the potential that additional reassortments can occur, resulting in drug resistant virus. Thus, additional antiviral approaches are urgently needed. DAS181 (Fludase®), a sialidase fusion protein, has been shown to have inhibitory activity against a large number of seasonal influenza strains and a highly pathogenic avian influenza (HPAI) strain (H5N1). Here, we examine the in vitro activity of DAS181 against a panel of 2009 oseltamivir-resistant seasonal H1N1 clinical isolates. The activity of DAS181 against nine 2009, two 2007, and two 2004 clinical isolates of seasonal IFV H1N1 was examined using plaque number reduction assay on MDCK cells. DAS181 strongly inhibited all tested isolates. EC50 values remained constant against isolates from 2004, 2007, and 2009,

There are no specific protocols for Anti-Swine H1N1 Neuraminidase antibody (ab91643). Please download our general protocols booklet

Summary Ortho- and parainfluenza viruses isolated from the cloacas of migrating feral ducks shot on the Mississippi flyway included three strains of influenza A virus (Hav6 Nav1, Hav6 Nl, Hav7 Neq2) as well as Newcastle disease virus. One influenza virus, A/duck/Memphis/546/74, possessed Hav3 haemagglutinin, but the neuraminidase was not inhibited by any of the known influenza reference antisera. The neuraminidase on this virus was related to the neuraminidases on A/duck/GDR/72 (H2 N?), A/turkey/Ontario/7732/66 (Hav 5 N?), A/duck/Ukraine/1/60 (Hav3 N?) and A/turkey/Wisconsin/68. We therefore propose that the neuraminidase on this group of influenza viruses be designated Nav6. The A/duck/Memphis/546/74 influenza virus caused an ocular discharge in 1 of 5 ducks and was shed in faeces for 10 days; it was stable in faecal samples for up to 3 days at 20 °C. These results suggest that ecological studies on influenza in avian species should include attempts to isolate virus from faeces. Faecal-oral

Influenza virus neuraminidase (NA) plays an essential role in release and spread of progeny virions, following the intracellular viral replication cycle. To test whether NA could also facilitate virus entry into cell, we infected cultures of human airway epithelium with human and avian influenza viruses in the presence of the NA inhibitor oseltamivir carboxylate. Twenty- to 500-fold less cells became infected in drug-treated versus nontreated cultures (P , 0.0001) 7 h after virus application, indicating that the drug suppressed the initiation of infection. These data demonstrate that viral NA plays a role early in infection, and they provide further rationale for the prophylactic use of NA inhibitors ...

Based on a strategy previously reported by us, we have synthesized D-xylo configured cyclohexenephosphonates designed to mimic the transition state of the sialidase reaction. The double bond orientation corresponds to the benchmark inhibitor Neu5Ac2en and we could selectively introduce hydroxyalkyl substituents in order to simulate the glycerol side-chain of neuraminic acid. The inhibitory activity of a set of compounds towards bacterial sialidases was tested and interesting differences in activity were found. (C) 2003 Elsevier Ltd. All rights reserved.. ...

Gangliosides play key roles in cell differentiation, cell-cell interactions, and transmembrane signaling. Sialidases hydrolyze sialic acids to produce asialo compounds, which is the first step of degradation processes of glycoproteins and gangliosides. Sialidase involvement has been implicated in some lysosomal storage disorders such as sialidosis and galactosialidosis. Neu2 is a recently identified human cytosolic sialidase. Here we report the first high resolution x-ray structures of mammalian sialidase, human Neu2, in its apo form and in complex with an inhibitor, 2-deoxy-2,3-dehydro-N-acetylneuraminic acid (DANA). The structure shows the canonical six-blade beta-propeller observed in viral and bacterial sialidases with its active site in a shallow crevice. In the complex structure, the inhibitor lies in the catalytic crevice surrounded by ten amino acids. In particular, the arginine triad, conserved among sialidases, aids in the proper positioning of the carboxylate group of DANA within the ...

X-NeuNAc, also known as CB1339 and X-Neu5Ac, is a novel substrate for chromogenic assay of neuraminidase activity in bacterial expression systems. X-NeuNAc can be used to facilitate the screening of bacterial colonies or plaques for the detection of either natural or mutant neuraminidase activity. Preliminary kinetic studies indicate that this compound is a good substrate (Km 0.89 x 10(-3) M) for neuraminidase and is quite stable under identical conditions in the absence of enzyme. These results suggest that X-Neu5Ac can be useful to screen for bacterially-encoded enzyme production directly on agar plates.

We have found that the entrapment of neuraminidase-treated lymphocytes in the liver leads to the induction of autoimmune cellular cytotoxic reactions.. Lymphocytes from mouse spleen and thymus were incubated with neuraminidase in vitro and injected i.v. into syngeneic recipients. Lymphocytic infiltrations into the liver were seen 7 days later with both types of cells. After repeated weekly injections of asialo-lymphocytes, destruction of liver tissue became apparent. Electronmicroscopic studies showed that hepatocytes, fat storage cells, and endothelial cells were affected, mainly at the hepatic periphery.. It is concluded that the adhesion of asialo-lymphocytes to liver cells induces their cytotoxic activity. Similar reactions may occur after paramyxovirus infection due to the action of viral neuraminidase.. ...

Adenocarcinoma, Animal, Ascitic-Fluid: cy, Binding-Sites-Antibody, Cells-Cultured, Complement, Cytotoxicity-Tests-Immunologic, Female, Male, Mammary-Neoplasms-Experimental, Mice, Neoplasm-Transplantation, Neuraminic-Acids: an, Neuraminidase, Vibrio: en. ...

In the influenza virus, the two relevant antigens are the surface proteins, hemagglutinin and neuraminidase.[4] The hemagglutinin is responsible for binding and entry into host epithelial cells while the neuraminidase is involved in the process of new virions budding out of host cells.[5] Sites recognized on the hemagglutinin and neuraminidase proteins by host immune systems are under constant selective pressure. Antigenic drift allows for evasion of these host immune systems by small mutations in the hemagglutinin and neuraminidase genes that make the protein unrecognizable to pre-existing host immunity.[6] Antigenic drift is this continuous process of genetic and antigenic change among flu strains.[7]. In human populations, immune (vaccinated) individuals exert selective pressure for single point mutations in the hemagglutinin gene that increase receptor binding avidity, while naive individuals exert selective pressure for single point mutations that decrease receptor binding avidity.[6] These ...

We have investigated the recognition of the PB1, neuraminidase, and matrix (M1) proteins of influenza virus A/NT/60/68 (H3N2 subtype) by secondary in vitro stimulated polyclonal cytotoxic T lymphocyte (CTL) populations. While these three proteins have different functions and cellular locations, they can all be recognized as target antigens. However, the immunogenicity of these proteins for CTLs is under strict genetic control. Thus, PB1 protein is recognized as a cross-reactive target antigen by CTLs raised in CBA (H-2k) but not BALB/c (H-2d) mice. CBA, but not BALB/c mice, also generate a low-level CTL response to the neuraminidase. This latter response was only detectable following in vivo priming of CBA mice with a recombinant vaccinia virus expressing neuraminidase (N2-VACC). The matrix protein, expressed from recombinant vaccinia virus M-VACC, was not recognized as an antigen by CTL generated from either CBA or BALB/c strains of mice. By contrast, human HLA-A2-restricted influenza virus-specific

The influenza virus NA, which is important for virus release from cells, also aids in infection by degrading the mucus barrier of the respiratory tract.

TY - JOUR. T1 - Computational studies of sialyllactones. T2 - Methods and uses. AU - Parrill, Abby L.. AU - Mamuya, Nellie. AU - Dolata, Daniel P.. AU - Gervay-Hague, Jacquelyn. PY - 1997. Y1 - 1997. N2 - N-Acetylneuraminic acid (1) is a common sugar in many biological recognition processes. Neuraminidase enzymes recognize and cleave terminal sialic acids from cell surfaces. Viral entry into host cells requires neuraminidase activity, thus inhibition of neuraminidase is a useful strategy for development of drugs for viral infections. A recent crystal structure for influenza viral neuraminidase with sialic acid bound shows that the sialic acid is in a boat conformation [Prot Struct Funct Genet 14: 327 (1992)]. Our studies seek to determine if structural pre-organization can be achieved through the use of sialyllactones. Determination of whether siallylactones are pre-organized in a binding conformation requires conformational analysis. Our inability to find a systematic study comparing the ...

Construction of a P. aeruginosa PAO1 neuraminidase null mutant A nanA null mutant (Δ2794) was constructed by allelic replacement. An in-frame nonpolar deletion allele was constructed by removing the nanA coding sequence corresponding to amino acids 5-435 of the predicted 438-residue polypeptide and used to replace the full-length gene (1,317 base pairs) by the method previously described (56). Primers were designed using the published DNA sequence for the neuraminidase gene (designated PA2794) from P. aeruginosa strain PAO1 (GenBank accession no. AF236853). A nanA complementation plasmid was constructed by cloning a PCR product corresponding to the full-length neuraminidase open reading frame into plasmid pMMBGW with either a gentamicin or a penicillin resistance marker (56). The complementation clone or an empty vector control was introduced into the Δ2794 mutant by conjugation and selection on gentamicin (40 μg/ml) or piperacillin (100 μg/ml). The same procedure was carried out to generate ...

On December 19, the U.S. Food and Drug Administration approved Rapivab (peramivir) to treat influenza infection in adults.. Influenza, commonly known as the flu, is a contagious respiratory illness caused by influenza viruses. Flu infections can range from mild to severe and can sometimes lead to hospitalization and death. According to the Centers for Disease Control and Prevention (CDC), 5-20 percent of the American population gets the flu and more than 200,000 people are hospitalized from seasonal flu-related complications each year.. Rapivab is an inhibitor of influenza virus neuraminidase, an enzyme that releases viral particles from infected cells. Neuraminidase inhibitors are commonly used to treat flu infection. Rapivab is the first neuraminidase inhibitor approved for intravenous (IV) administration and is administered as a single IV dose. It is intended for patients 18 years and older who have acute uncomplicated influenza and have shown symptoms of flu for no more than two days.. For ...

TY - JOUR. T1 - Optimal conditions for the assay of fibroblast neuraminidase with different natural substrates. AU - Caimi, L.. AU - Lombardo, A.. AU - Preti, A.. AU - Wiesmann, U.. AU - Tettamanti, G.. PY - 1979/11/9. Y1 - 1979/11/9. N2 - A method for the assay of neuraminidase in human cultured fibroblasts has been worked out. The substrates, all naturally occurring, were: sialyloligosaccharides (α(2 → 3)sialyllactose, α(2 → 6)sialyllactose, disialyllactose), sialylglycolipids (disialogangliosides GD1a and GD1b), sialylglycoproteins and sialylglycopeptides (ovine submaxillary glycoprotein and its pronase-glycopeptides). The method was based on the determination of the enzymically liberated N-acetylneuraminic acid (NeuAc) by a chromatographic-colorimetric microprocedure. The enzyme acted on sialyloligosaccharides and, in the presence of Triton X-100, on gangliosides, while it did not appreciably affect sialylglycoproteins and sialylglycopeptides. The optimum pH was 4.0 for all tested ...

Influenza viruses have been identified with NA molecules that serve as receptor binding proteins, a function usually reserved for the HA glycoprotein.

Neuraminidase inhibitors provide a small benefit by shortening the duration of illness in children with seasonal influenza and reducing household transmission. They have little effect on asthma exacerbations or the use of antibiotics. Their effects on the incidence of serious complications, and on t …

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Avian Influenza A Neuraminidase兔多克隆抗体(ab21305)经ELISA实验严格验证，被7篇文献引用。所有产品均提供质保服务，中国75%以上现货。

The worldwide spread of H5N1 avian influenza has raised concerns that this virus might acquire the ability to pass readily among humans and cause a pandemic. Two anti-influenza drugs currently being used to treat infected patients are oseltamivir (Tamiflu) and zanamivir (Relenza), both of which target the neuraminidase enzyme of the virus. Reports of the emergence of drug resistance make the development of new anti-influenza molecules a priority. Neuraminidases from influenza type A viruses form two genetically distinct groups: group-1 contains the N1 neuraminidase of the H5N1 avian virus and group-2 contains the N2 and N9 enzymes used for the structure-based design of current drugs. Here we show by X-ray crystallography that these two groups are structurally distinct. Group-1 neuraminidases contain a cavity adjacent to their active sites that closes on ligand binding. Our analysis suggests that it may be possible to exploit the size and location of the group-1 cavity to develop new ...

Neuraminidase inhibitors are the only licensed antiviral medications available to treat avian influenza A(H7N9) virus infections in humans. According to a neuraminidase inhibition assay, an R292K substitution reduced antiviral efficacy of inhibitors, especially oseltamivir, and decreased viral fitness in cell culture. Monitoring emergence of R292K-carrying viruses using a pH-modified neuraminidase inhibition assay should be considered.

The Y155H amino acid substitution in the neuraminidase gene (NA) has previously been associated with highly reduced inhibition by neuraminidase inhibitors in the seasonal H1N1 influenza A virus which circulated in humans before the 2009 pandemic. During the 2012/13 epidemic season in Spain, two A(H1N1)pdm09 viruses bearing the specific Y155H substitution in the NA were detected and isolated from two patients diagnosed with severe respiratory syndrome and pneumonia requiring admission to the intensive care unit. Contrary to what was observed in the seasonal A(H1N1) viruses, neither of the Y155H A(H1N1)pdm09 viruses described here showed a phenotype of reduced inhibition by NAIs as determined by the neuraminidase enzyme inhibition assay (MUNANA). High-throughput sequencing of the NA of both Y155H viruses showed that they were composed to >99% of H155 variants. We believe that this report can contribute to a better understanding of the biological significance of amino acid substitutions in the

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Neuraminidase, 1 ml. Neuraminidases or sialidases are exoglycosidases that catalyze the cleavage of a glycosidically linked terminal N acetyl neuraminic acid from sialylated glycoconjugates.

Modules of approx. 200 residues, found at the N-terminus of GH33 sialidases. Can also be found inserted in the β-propeller of GH33 sialidases. The sialic acid binding function has been demonstrated for the N-terminal CBM40 of Vibrio cholerae sialidase (Moustafa et al. (2004) J Biol Chem 279:40819-26) (PMID: 15226294 ...

All Images are for Editorial Use Only). This negatively-stained transmission electron micrograph (TEM) revealed the presence of a number of Hong Kong flu virus virions, the H3N2 subtype of the influenza A virus. This virus is a Orthomyxoviridae virus family member, and was responsible for the flu pandemic of 1968-1969, which infected an estimated 50,000,000 people in the United States, killing 33,000. Note the proteinaceous coat, or capsid, surroundind each virion, and the hemagglutinin-neuraminidase spikes, which differ in terms of their molecular make-up from strain to strain.. There are many different subtypes of type A influenza viruses. These subtypes differ because of changes in certain proteins on the surface of the influenza A virus (hemagglutinin [HA] and neuraminidase [NA] proteins). There are 16 known HA subtypes and 9 known NA subtypes of influenza A viruses. Many different combinations of HA and NA proteins are possible. Each combination represents a different subtype. All known ...

Supplementary Materials? IRV-13-522-s001. hosts with a number of NA subtypes (N1\N9). solid course=kwd-title Keywords: antiviral medications, avian, influenza A trojan, level of resistance, zoonotic 1.?Launch Zoonotic and pet influenza A infections cause a substantial risk to community wellness; they can cause severe disease in humans with little safety afforded by seasonal vaccination due to antigenic differences.1 NAIs are routinely used to treat individuals infected with influenza viruses, regardless of subtype, and the oseltamivir is the most commonly prescribed anti\influenza therapeutic. Antiviral level of resistance Pradefovir mesylate can emerge in character or pursuing treatment with NAIs through adjustments to the top antigen NA that have an effect on neuraminidase inhibitor (NAI) binding. Such changes may cause resistance to 1 or even more NAIs. 2 While NA gene series evaluation can be used to display screen infections for set up markers of level of resistance frequently, genetic ...

购买我们的Avian Influenza A Neuraminidase肽。ab39804可作为ab21304的封闭肽并经过Blocking, ELISA实验验证。Abcam提供免费的实验方案，操作技巧及专业的支持。

The protein encoded by this gene is a lysosomal enzyme that cleaves terminal sialic acid residues from substrates such as glycoproteins and glycolipids. In the lysosome, this enzyme is part of a heterotrimeric complex together with beta-galactosidase and cathepsin A (the latter is also referred to as protective protein). Mutations in this gene can lead to sialidosis, a lysosomal storage disease that can be type 1 (cherry red spot-myoclonus syndrome or normosomatic type), which is late-onset, or type 2 (the dysmorphic type), which occurs at an earlier age with increased severity. [provided by RefSeq, Jul 2008 ...

Expression-ready H12N5 Neuraminidase/NA cDNA ORF clone (VG40237-UT) with enhanced promotor in expression vector (pCMV3-untagged) is confirmed by full-length sequence and validated in expression capability for gene expression studies or other applications. Quote for bulk production.

[button size=small text=MSDS & Datasheet link=/wp-content/uploads/media/BCDatasheets_C_10.26/E & EC/EC-32118-S.pdf]Neuraminidase (Isoenzyme S), 1

A radiometric method for the assay of ganglioside sialidase in cultured human fibroblasts was set up. As substrate, highly radioactive (1.28 Ci/mmol) ganglioside GD1a isotopically tritium-labeled at carbon C-3 of the long chain base was employed; the liberated, and TLC separated [3H]GM1 was determined by computer-assisted radiochromatoscanning. Under experimental conditions that provided a low and quite acceptable (4-5%) coefficient of variation, the detection limit of the method was 0.1 nmol of liberated GM1, using as low as 10 μg of fibroblast homogenate as protein. The detection limit could be lowered to 0.02-0.03 nmol, adopting conditions that, however, carried a higher analytical error (coefficient of variation over 10%). The content of ganglioside sialidase in human fibroblasts cultured in 75-cm2 plastic flasks was 5.8 ∓ 2.5 (SD) nmol liberated GM1 h-1 mg protein-1. Subfractionation studies performed on fibroblast homogenate showed that the ganglioside sialidase was mainly associated ...

Lysosomal Storage Disorders are a class of inherited metabolic conditions that result from alterations in the function of lysosomal enzymes. One example is GM1 Gangliosidosis (GM1), a disorder in which the activity of β-galactosidase is deficient resulting in neurodegeneration and early death. The enzyme, β-gal, is a member of the Lysosomal Multienzyme Complex (LMC), which transports proteins to the lysosome and enables various functions. LMC members include β-gal, α-neuraminidase and the Protective Protein Cathepsin A (PPCA). In a unique ovine model of GM1, there is a primary deficiency in the activity of β- galactosidase and a secondary deficiency in α-neuraminidase activity. The cause of the secondary deficiency in α-neuraminidase activity, which is not seen in any other animal model of GM1, is currently unknown. The α-neuraminidase protein is coded for by the NEU1 gene and is, a glycohydrolitic enzyme that is active in the lysosome. The secondary deficiency of α- neuraminidase seen in our

Our study provides validated virus inactivation protocols that allow implementation of phenotypic NAI susceptibility testing, HI assessment (for serology as well antigenic characterization of viruses), and T-cell response characterization using avian, swine, and human influenza viruses under BSL-2 containment conditions. Using pandemic influenza A(H1N1)v virus strains, we illustrate the ease of carrying out Triton X-100 and formalin virus inactivation protocols prior to the assessment of A(H1N1)v virus susceptibility to antivirals and the characterization of B- and T-cell responses, respectively, outside the BSL-3 high-containment facility. These inactivation protocols facilitate the diagnostic examination of pandemic influenza viruses by applying standard laboratory conditions at BSL-2.. Considering results from documented studies and taking ease of use under BSL-3 conditions into account, therefore excluding, e.g., irradiation protocols, we evaluated human A(H3N2) and avian A(H7N3) virus ...

Our study provides validated virus inactivation protocols that allow implementation of phenotypic NAI susceptibility testing, HI assessment (for serology as well antigenic characterization of viruses), and T-cell response characterization using avian, swine, and human influenza viruses under BSL-2 containment conditions. Using pandemic influenza A(H1N1)v virus strains, we illustrate the ease of carrying out Triton X-100 and formalin virus inactivation protocols prior to the assessment of A(H1N1)v virus susceptibility to antivirals and the characterization of B- and T-cell responses, respectively, outside the BSL-3 high-containment facility. These inactivation protocols facilitate the diagnostic examination of pandemic influenza viruses by applying standard laboratory conditions at BSL-2.. Considering results from documented studies and taking ease of use under BSL-3 conditions into account, therefore excluding, e.g., irradiation protocols, we evaluated human A(H3N2) and avian A(H7N3) virus ...

Gangliosides are sialic acid-containing glycosphingolipids mainly expressed at the outer leaflet of the plasma membrane. Sialidase NEU3 is a key enzyme in the catabolism of gangliosides with its up-regulation having been observed in human cancer cells. In the case of CME (clathrin-mediated endocytosis), although this has been widely studied, the role of NEU3 and gangliosides in this cellular process has not yet been established. In the present study, we found an increased internalization of Tf (transferrin), the archetypical cargo for CME, in cells expressing complex gangliosides with high levels of sialylation. The ectopic expression of NEU3 led to a drastic decrease in Tf endocytosis, suggesting the participation of gangliosides in this process. However, the reduction in Tf endocytosis caused by NEU3 was still observed in glycosphingolipid-depleted cells, indicating that NEU3 could operate in a way that is independent of its action on gangliosides. Additionally, internalization of ...

TY - JOUR. T1 - Neuraminidase from Trypanosoma cruzi. T2 - Analysis of enhanced expression of the enzyme in infectious forms. AU - Harth, G.. AU - Haidaris, C. G.. AU - So, M.. PY - 1987. Y1 - 1987. N2 - We purified the neuraminidase (sialidase, acylneuraminyl hydrolase, EC 3.2.1.18) from the protozoan parasite Trypanosoma cruzi, strain Y, and examined the developmental regulation of the enzyme. The detectable amount of enzyme activity increased 10- to 20-fold upon conversion of the parasite from the noninfectious epimastigote form to the infectious trypomastigote form. The enzyme was purified from membranes of trypomastigotes ,5000-fold to apparent homogeneity and migrated as an entity of M(r) 60,000 under denaturing conditions. Antibodies produced in rabbits against the denatured protein recognized the neuraminidase in membrane extracts from the infectious stage but not from the noninfectious stage. Sera from a patient with acute chagasic disease also reacted strongly with the neuraminidase. ...

Antibodies are a major means of protection from influenza virus infections. Antibody-mediated immunity is the basis of current vaccines and most efforts to improve immunity to influenza. Influenza virus vaccinations induce antibodies that predominantly target the immunodominant globular head of influenza HA, blocking viral attachment to prevent infection (4, 5). However, immunity to the HA head domain is highly susceptible to influenza antigenic drift or viral mutation, which introduces novel amino acids and glycosylation sites that allow the virus to evade existing immunity. The stalk is a more conserved domain, allowing antibodies that target this region to neutralize a wide spectrum of influenza virus subtypes (6-9). The currently appreciated mechanism of protection by HA stalk-reactive antibodies is to lock the HA trimer in a prefusion conformation, preventing pH-triggered conformational changes upon viral uptake into endocytic compartments. This conformational change exposes the fusion ...

TY - JOUR. T1 - Neuraminidase and contractile responses to norepinephrine in rat tail artery. AU - Rice, J. H.. AU - Webb, R. C.. PY - 1984/1/1. Y1 - 1984/1/1. N2 - Sialic acids are negatively charged groups in the carbohydrate side chains of glycolipids and glycoproteins which line the external membrane surface. The goal of this study was to characterize the effect of neuraminidase, which selectively cleaves sialic acids, on contractile activity in vascular smooth muscle. Helically cut strips of rat tail artery were mounted in an organ chamber and isometric contractions were recorded. Following treatment with neuraminidase (0.2 U/ml, 1 h), contractile responses to norepinephrine were signficantly greater than control responses. Phasic concentrations to norepinephrine in calcium-free medium were not altered by neuraminidase, whereas following calcium depletion with EGTA, contractile responses to added calcium were greater in enzyme-treated strips than in control when activated with ...

Background: Little is known about whether neuraminidase inhibitors are effective Vorinostat purchase for children infected with oseltamivir-resistant influenza A(H1N1) viruses.. Methods: Children aged 15 years and younger having influenza-like illness and who visited outpatient clinics within 48 hours Bcl 2 inhibitor of fever onset were enrolled from 2006-2007 to 2008-2009 influenza seasons in Japan. Patients received oseltamivir, zanamivir, or no treatment after screening by a rapid antigen test. Nasopharyngeal swabs were collected before antiviral therapy. and were used for virus isolation. Oseltamivir resistance was determined by detection of the H275Y mutation in neuraminidase, and susceptibility test using neuraminidase inhibition assay. Daily body temperature was evaluated according to drug type and susceptibility by univariate and multivariate analyses.. Results: Of 1647 patients screened, 238 oseltamivir-resistant H1N1 cases (87 oseltamivir-treated, 64 zanamivir-treated, and 87 ...

Although oseltamivir-resistant pandemic influenza A(H1N1)pdm09 is uncommon in immunocompetent individuals, a recent report from Newcastle, Australia, showed the first sustained community spread, from June to August 2011, of oseltamivir-resistant influenza A(H1N1)pdm09 virus carrying the H275Y neuraminidase (NA) mutation. To determine the frequency and the extent of this viral variant spread in the nearest major city to Newcastle, we performed a sequence-based genotypic assessment on samples from 143 oseltamivir untreated and 23 oseltamivir post-treatment individuals with influenza collected contemporaneously in Sydney, 120 km southwest of Newcastle. The detection of two of 143 (1.4%) community-derived samples containing H275Y suggests a low prevalence of oseltamivir-resistant influenza A(H1N1)pdm09 virus in the general community and no convincing evidence of spread of the NA H275Y-bearing influenza A(H1N1)pdm09 virus. In oseltamivir treated patients, oseltamivir-resistant influenza A(H1N1)pdm09 virus

Background: Influenza viruses present a serious threat to global health. Resistance to current antiviral drugs underscore the need for additional therapies. Nitazoxanide (NTZ) and its active metabolite tizoxanide (TIZ) were found to inhibit the replication of H1N1 PR8 influenza A virus by a novel mechanism, impairing hemagglutinin maturation and virus morphogenesis. Herein we investigated the activity of NTZ and TIZ against a broad spectrum of human and avian influenza strains. Furthermore, the synergistic potential of NTZ in combination with neuraminidase inhibitors (NI) oseltamivir (OST) and zanamivir (ZAN) was explored. Methods: The effect of NTZ/TIZ activity was investigated in MDCK cells after infection (5 HAU/105 cells) with the following influenza A strains: H1N1 A/Puerto Rico/8/34 (PR8), H1N1 A/Wisconsin/33, H3N2 A/Firenze/7/03, H3N2 amantadine-resistant A/Parma/06/07 (AMD-R), H1N1 OST-resistant A/Parma/24/09 (OST-R), and avian H5N9-LP A/Ck/Italy/9097/97, H1N1 A/Goose/Italy/296246/03 and ...

Human infections with Eurasian avian-like swine influenza H1N1 viruses have been reported in China in past years. One case resulted in death and others were mild case. In 2016, the World Health Organization recommended the use of A/Hunan/42443/2015(H1N1) virus to construct the first candidate vaccine strain for Eurasian avian-like swine influenza H1N1 viruses. Previous reports showed that the neuraminidase of A/Puerto Rico/8/34(H1N1) might improve the viral yield of reassortant viruses. Therefore, we constructed two reassortant candidate vaccine viruses of A/Hunan/42443/2015(H1N1) by reverse genetic technology, with (6+2) and (7+1) gene constitution, respectively. The (6+2) virus had hemagglutinin and neuraminidase from A/Hunan/42443/2015, and the (7+1) one had hemagglutinin from A/Hunan/42443/2015, while all the other genes were from A/Puerto Rico/8/34. Our data revealed that although the neuraminidase of the (7+1) virus was from high yield A/Puerto Rico/8/34, the hemagglutination titer and the ...

We have cloned the Bacteroides fragilis TAL2480 neuraminidase (NANase) structural gene, nanH, in Escherichia coli. This was accomplished by using the cloning shuttle vector pJST61 and a partial Sau3A library of TAL2480 chromosomal inserts created in E. coli. The library was mobilized into the NANase-deficient B. fragilis TM4000 derivative TC2. NANase-producing colonies were enriched by taking advantage of the inability of TC2, but not the wild-type of NANase+ revertant, to grow in vitro in fluid aspirated from the rat granuloma pouch. Plasmids pJST61-TCN1 and pJST61-TCN3, containing inserts of 9.1 and 4.5 kilobases (kb), respectively, were found in the TC2 derivatives that grew in the rat pouch medium. In B. fragilis, NANase production from the two plasmids was inducible by free N-acetylneuraminic acid or sialic acid-containing substrates, just as in the parental TAL2480 strain. However, when these plasmids were transferred back to E. coli, NANase activity was barely detectable. A 3.5-kb portion ...

TY - JOUR. T1 - Outside-binding site mutations modify the active sites shapes in neuraminidase from influenza A H1N1. AU - Tolentino-Lopez, Luis. AU - Segura-Cabrera, Aldo. AU - Reyes-Loyola, Paola. AU - Zimic, Mirko. AU - Quiliano, Miguel. AU - Briz, Veronica. AU - Muñoz-Fernández, Angeles. AU - Rodríguez-Pérez, Mario. AU - Ilizaliturri-Flores, Ian. AU - Correa-Basurto, Jose. PY - 2013/1. Y1 - 2013/1. N2 - The recent occurrence of 2009 influenza A (H1N1) pandemic as well as others has raised concern of a far more dangerous outcome should this virus becomes resistant to current drug therapies. The number of clinical cases that are resistant to oseltamivir (Tamiflu®) is larger than the limited number of neuraminidase (NA) mutations (H275Y, N295S, and I223R) that have been identified at the active site and that are associated to oseltamivir resistance. In this study, we have performed a comparative analysis between a set of NAs that have the most representative mutations located outside the ...

Rapid shifts in microbial composition frequently occur during intestinal inflammation, but the mechanisms underlying such changes remain elusive. Here we demonstrate that an increased caecal sialidase activity is critical in conferring a growth advantage for some bacteria including Escherichia coli (E. coli) during intestinal inflammation in mice. This sialidase activity originates among others from Bacteroides vulgatus, whose intestinal levels expand after dextran sulphate sodium administration. Increased sialidase activity mediates the release of sialic acid from intestinal tissue, which promotes the outgrowth of E. coli during inflammation. The outburst of E. coli likely exacerbates the inflammatory response by stimulating the production of pro-inflammatory cytokines by intestinal dendritic cells. Oral administration of a sialidase inhibitor and low levels of intestinal α2,3-linked sialic acid decrease E. coli outgrowth and the severity of colitis in mice. Regulation of sialic acid ...

Clinical trial for Influenza Vaccine | Influenza , Study to Assess Efficacy and Safety of Baloxavir Marboxil In Combination With Standard-of-Care Neuraminidase Inhibitor In Hospitalized Participants With Severe Influenza

HMTK KARUNARATHNA, RAPM PERERA, VJ FANG, HL YEN, BJ COWLING AND JSM PEIRIS (2016). Serum anti-neuraminidase antibody (Anti-NA N1) responses in human pandemic H1N1 2009 Influenza A virus infections and cross reactivity with seasonal H1N1 virus. Presented at Options IX for the control of influenza conference, Chicago, Illinois, USA held from 24th to 28th August 2016. (Best poster presentation at the symposium in the theme of Public Health ...

1. Riegger D*, Hai R*, Dornfeld D, Manz B, Leyva-Grado V, Sanchez-Aparicio MT, Albrecht RA, Palese P, Haller O, Schwemmle M, Garcia-Sastre A, Kochs G, Schmolke M. 2015. The nucleoprotein of newly emerged H7N9 influenza A virus harbors a unique motif conferring resistance to antiviral human MxA. J Virol 89:2241-2252. (*: These authors contributed equally to this work.). 2. Leyva-Grado, V. H.*, Hai, R.*, Fernandes, F., Belicha-Villanueva, A., Carter, C., and Yondola, M. 2014. Modulation of an ectodomain motif in the influenza A virus neuraminidase alters tetherin sensitivity and results in virus attenuation in vivo. Journal of molecular biology 426:1308-1321. (*: These authors contributed equally to this work.). 3. Hai, R., Schmolke, M., Leyva-Grado, V. H., Thangavel, R. R., Margine, I., Jaffe, E. L., Krammer, F., Solorzano, A., Garcia-Sastre, A., Palese, P., and Bouvier, N. M. 2013. Influenza A(H7N9) virus gains neuraminidase inhibitor resistance without loss of in vivo virulence or ...

A series of substrates, sialyl(2 leads to 6)GalNAc and ganglioside GM3, containing either N-acetylneuraminic acid (AcNeu) or N-glycolloylneuraminic acid (GcNeu), has been prepared. The trisaccharide GcNeu(2 leads to 3)lactose was preapred by ozonolysis of GcNeu-GM3, and the disaccharides AcNeu(2 leads to 6)GalNAc and GcNeu(2 leads to 6)GalNAc were isolated from bovine submandibular-gland mucin by alkali elimination. Sialidases from Newcastle-disease virus, fowl-plague virus, influenza virus A2, Clostridium perfringens, Vibrio cholerae, Arthrobacter ureafaciens and human liver lysosomes were studied with the above substrates and all showed poorer cleavage of GcNeu-containing substrates when compared with the corresponding AcNeu-containing compounds. This was reflected in the Km and Vmax. values of these sialidases. Differences between viral and bacterial sialidases could be detected on the basis of their kinetic constants and time curves of sialic acid release. Preferred release of AcNeu relative ...

Bacteria are developing resistance against β-lactam antibiotics by various genetic mechanisms of which plasmid acquiring is the most deadly. Amongst others bacteria acquire resistance by degradation or modification of the antibiotic before it reaches the target site, alteration of the antibiotic site and the prevention of access of the antibiotic to the target by forced efflux.. One of the most problematic bacteria known to roam the corridors and wards in hospitals is Staphylococcus aureus, a Gram positive bacterium. We conduct computational structural biology and reaction dynamics studies on S. Aureus to develop lead drugs that may be a new form of antibiotic.. Ian L. Rogers and Kevin J. Naidoo/ Profiling Transition-State Configurations on the Trypanosoma cruzi trans-Sialidase Free-Energy Reaction Surfaces. J. Phys Chem B. 2015. 119, 1192-1201.. Umraan Hendricks, Werner Crous and Kevin J. Naidoo. Computational Rationale for the Selective Inhibition of the Herpes Simplex Virus Type 1 Uracil-DNA ...

Bacteria are developing resistance against β-lactam antibiotics by various genetic mechanisms of which plasmid acquiring is the most deadly. Amongst others bacteria acquire resistance by degradation or modification of the antibiotic before it reaches the target site, alteration of the antibiotic site and the prevention of access of the antibiotic to the target by forced efflux.. One of the most problematic bacteria known to roam the corridors and wards in hospitals is Staphylococcus aureus, a Gram positive bacterium. We conduct computational structural biology and reaction dynamics studies on S. Aureus to develop lead drugs that may be a new form of antibiotic.. Ian L. Rogers and Kevin J. Naidoo/ Profiling Transition-State Configurations on the Trypanosoma cruzi trans-Sialidase Free-Energy Reaction Surfaces. J. Phys Chem B. 2015. 119, 1192-1201.. Umraan Hendricks, Werner Crous and Kevin J. Naidoo. Computational Rationale for the Selective Inhibition of the Herpes Simplex Virus Type 1 Uracil-DNA ...

SWISS-MODEL Template Library (SMTL) entry for 1s0j.1. Trypanosoma cruzi trans-sialidase in complex with MuNANA (Michaelis complex)

Description: Oseltamivir is an inhibitor of influenza neuraminidase [1].Oseltamivir is a prodrug that is converted by intestinal and/or hepatic esterases to the neuraminidase inhibitor molecule, oseltamivir carboxylate ...

Control of flavonoid derivatives inhibitors release through the inhibition of neuraminidase has been identified as a potential target for the treatment of H1N1 influenza disease. We have employed molecular dynamics simulation techniques to optimize the 2009 H1N1 influenza neuraminidase X-ray crystal structure. Molecular docking of the compounds revealed the possible binding mode. Our molecular dynamics simulations combined with the solvated interaction energies technique was applied to predict the docking models of the inhibitors in the binding pocket of the H1N1 influenza neuraminidase. In the simulations, the correlation of the predicted and experimental binding free energies of all 20 flavonoid derivatives inhibitors is satisfactory, as indicated by R2 = 0.75.

Cited for: VARIANTS SIALIDOSIS VAL-68; GLY-182; ARG-227; ARG-240; TYR-260; PHE-270; VAL-298; SER-328 AND PRO-363; CHARACTERIZATION OF VARIANTS SIALIDOSIS VAL-68; GLY-182; ARG-227; TYR-260; PHE-270; VAL-298; SER-328 AND PRO-363; Novel missense mutations in the human lysosomal sialidase gene in sialidosis patients and prediction of structural alterations of mutant enzymes. ...

Endosialidase (endo-N-acetylneuraminidase) is a tailspike enzyme of bacteriophages specific for human pathogenic Escherichia coli K1, which specifically recognizes and degrades polySia (polysialic acid). polySia is also a polysaccharide of the capsules of other meningitis- and sepsis-causing bacteria, and a post-translational modification of the NCAM (neural cell-adhesion molecule). We have cloned and sequenced three spontaneously mutated endosialidases of the PK1A bacteriophage and one of the PK1E bacteriophage which display lost or residual enzyme activity but retain the binding activity to polySia. Single to triple amino acid substitutions were identified, and back-mutation constructs indicated that single substitutions accounted for only partial reduction of enzymic activity. A homology-based structural model of endosialidase revealed that all substituted amino acid residues localize to the active site of the enzyme. The results reveal the importance of non-catalytic amino acid residues for ...

Endosialidase (endo-N-acetylneuraminidase) is a tailspike enzyme of bacteriophages specific for human pathogenic Escherichia coli K1, which specifically recognizes and degrades polySia (polysialic acid). polySia is also a polysaccharide of the capsules of other meningitis- and sepsis-causing bacteria, and a post-translational modification of the NCAM (neural cell-adhesion molecule). We have cloned and sequenced three spontaneously mutated endosialidases of the PK1A bacteriophage and one of the PK1E bacteriophage which display lost or residual enzyme activity but retain the binding activity to polySia. Single to triple amino acid substitutions were identified, and back-mutation constructs indicated that single substitutions accounted for only partial reduction of enzymic activity. A homology-based structural model of endosialidase revealed that all substituted amino acid residues localize to the active site of the enzyme. The results reveal the importance of non-catalytic amino acid residues for ...

Sigma-Aldrich offers abstracts and full-text articles by [Koji Yamamoto, Kohta Takahashi, Kazuhiro Shiozaki, Kazunori Yamaguchi, Setsuko Moriya, Masahiro Hosono, Hiroshi Shima, Taeko Miyagi].

Learn how flu viruses get into and out of your cells using Hemagglutinin and Neuraminidase proteins on their surface. Rishi is a pediatric infectious disease physician and works at Khan Academy. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

The team examined blood samples from people who were vaccinated against flu and those who were diagnosed with either the H3N2 or H1N1 influenza viruses. They found that flu vaccines rarely induced anti-NA antibodies. In contrast, natural flu infection induced anti-NA antibodies at least as often as anti-HA ones.. Lab experiments showed that anti-NA antibodies induced during natural flu infection reacted against diverse strains of flu virus. To test whether they could also protect against diverse strains, the researchers isolated anti-NA antibodies from the H3N2 and H1N1 influenza patients. When the team gave anti-NA antibodies derived from the H3N2 patients to mice and infected the mice with a different H3N2 virus strain, 11 of the 13 tested antibodies protected the mice. Four of eight anti-NA antibodies derived from the H1N1 patients protected mice against both a similar H1N1 virus strain and an H5N1-like strain. Past studies have found far less overlap among anti-HA antibodies.. These findings ...

Antibodies for proteins involved in exo-alpha-(2->8)-sialidase activity pathways, according to their Panther/Gene Ontology Classification

Tamiflu (oseltamivir phosphate) is an antiviral drug approved for treatment of uncomplicated influenza A and B in patients 1 year of age or older. It is also approved for prophylaxis (prevention) of influenza in people 13 years or older after household contact or at high risk for exposure during influenza season. Tamiflu is one of a group of anti-influenza drugs called neuraminidase inhibitors that act by blocking the viral enzyme neuraminidase which helps the influenza virus invade cells in the respiratory tract ...

With enhanced promotor, Neuraminidase/NA cDNA ORF Clone, Influenza B in pCMV3-SP-N-His is expression-ready, and confirmed by full-length sequence & expression validation

The study-led by David Baltimore, Caltechs Robert Andrews Millikan Professor of Biology and recipient of the 1975 Nobel Prize in Physiology or Medicine, and postdoctoral scholar Jesse D. Bloom-appears in the June 4 issue of the journal Science. Tamiflu and other antiviral drugs directly target viruses, unlike vaccines, which instead stimulate our bodys immune system to respond to the pathogens after an infection is established. In a flu infection, viruses bind to sialic acid on the surface of a host cell using a protein called hemagglutinin (the H in H1N1). The viruses then enter the cell and replicate. When the newly minted viruses exit the cell, they too bind to sialic acid. The viruses then use a protein called neuraminidase (the N in H1N1) to cut the sialic acid, freeing themselves to infect new cells. This process, however, is blocked by Tamiflu, which prevents neuraminidase from cleaving the sialic acid. It does this by binding in the active site of the neuraminidase molecule, ...

Coronavirus drug is an antiviral agent that you can buy right now. When taken orally, it is hydrolyzed, turning into an active form of medicine - oseltamivir carboxylate. Its mechanism of action is related to the ability to inhibit neuraminidase (enzymes involved in replication) of influenza viruses A and B. Meanwhile, the ability of viral particles to penetrate the human cells, as well as the exit of virions from an infected human cell, is impaired. This limits the spread of the pathogen through the respiratory tract ...

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The chemical relationship of the seven forms of human liver α-L fucosidase has been studied by isoelectric focusing of neuraminidase- and sialyltransf

Tamiflu is the current standard treatment for patients with influenza. A recent study has presented results demonstrating that treatment with Tamiflu reduces the time to relief of flu symptoms, however, increases the occurrence of nausea and vomiting. Tamiflu (Oseltamivir) is a neuraminidase inhibitor that blocks the activity of influenza virus enzymes. During the 2009 influenza… ...

Hydrolysis of alpha-(2->3)-, alpha-(2->6)-, alpha-(2->8)- glycosidic linkages of terminal sialic acid residues in oligosaccharides, glycoproteins, glycolipids, colominic acid and synthetic substrates ...

A group of 23 volunteers were each inoculated with 600 CCA of a new form of influenza virus A/England/42/72 vaccine; this vaccine consisted of purified haemagglutinin and neuraminidase antigens adsorbed to alhydrogel. No significant reactions to the vaccine were reported. Twenty-two volunteers produced increased titres of serum HI antibody, and all showed increased titres of NI antibody after immunization. Thus, for volunteers with no pre-immunization serum HI antibody, the geometric mean titre of serum antibody increased from 1/5 to 1/196 after immunization. Ten volunteers developed local neutralizing antibody after immunization; this antibody response was detected most frequently in volunteers who showed the greater serum antibody response to immunization, and in nasal washings with the higher concentrations of protein and IgA. Ten weeks after immunization, the vaccinees and a group of matched controls were inoculated intranasally with attenuated A/England/42/72 virus. Evidence of infection ...

Widespread use of antiviral therapy can lead to drug resistance, and resistance to neuraminidase inhibitors has been documented in type A influenza. During an i

Read Antiviral Drug Strategies by Raimund Mannhold available from Rakuten Kobo. Sign up today and get $5 off your first purchase. By focusing on general molecular mechanisms of antiviral drugs rather than therapies for individual viruses, this ready Author: Raimund Mannhold, Hugo Kubinyi, Gerd Folkers. Description. It begins with a general discussion of antiviral strategies, followed by a broad survey of known viral targets, such as reverse transcriptases, proteases, neuraminidases, RNA polymerases, helicases and primases, as well as their known inhibitors. The final section contains several cases studies of recent successful antiviral drug. It begins with a general discussion of antiviral strategies, followed by a broad survey of known viral targets, such as reverse transcriptases, proteases, neuraminidases, RNA polymerases, helicases and primases, as well as their known inhibitors. The final section contains several cases studies of recent successful antiviral drug development. Strategies of ...

Proteazomi su proteinski kompleksi koji su nađeni svih eukariota i Archaea, a i kod nekih bakterija. Kod eukariota se nalaze u jedru i citoplazmi.[1] Glavna funkcija proteazoma je razgradnja nepotrebnih ili oštećenih proteina, u procesu proteolize, odnosno hemijske reakcije u kojoj se razlažu peptidne veze. Enzimi koji kataliziraju ove reakcije su proteaze.[2][3][4] Proteazomi su dio velikog mehanizma kojim ćelije reguliraju koncentraciju pojedinih proteina i razgrađuju nepravilno savijene proteine. U procesu degradacije nastaju peptidi sa oko sedam do osam aminokiselina, koji se zatim razrađuju u aminokiseline i koriste u sintezi novih proteina.[5] Za degradaciju, proteini se obilježavaju malim proteinom zvanim ubikvitin. Reakcija obilježavanja se katalizira enzimima ubikvitinskim ligazama. Vezanje jednog ubikvitina na protein je signal drugim ligazama da vežu dodatne molekule ubikvitina. Rezultat je poliubikvitinski lanac za koji se veže proteazom, što omogućava degradaciju ...