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.
2C4A: STRUCTURE OF NEURAMINIDASE SUBTYPE N9 COMPLEXED WITH 30 MM SIALIC ACID (NANA, NEU5AC), CRYSTAL SOAKED FOR 3 HOURS AT 291 K.
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 ...
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
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 ...
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.
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 ...
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.
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.
CHIMERIZATION AND CHARACTERIZATION OF A MONOCLONAL ANTIBODY WITH POTENT NEUTRALIZING ACTIVITY ACROSS MULTIPLE... | METHOD FOR DETERMINING DELETIONS IN HBV PRE-S2 REGION | CELL CULTURE MEDIUM | MODIFIED PIGMENT EPITHELIUM-DERIVED FACTOR (PEDF) PEPTIDES AND USES THEREOF FOR TREATING NEOVASCULAR DISEASES,... | EGFR and C-Met Fibronectin Type III Domain Binding Molecules |
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 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 (NA), a surface glycoprotein of influenza virus, is a potential target for design of antiinfluenza agents. The crystal structure of influenza virus neuraminidase showed that in the active site 11 residues are universally conserved among all strains known so far. Several potent inhibitors based on the carbohydrate compound 2-deoxy-2,3-didehydro-D-N-acetylneuraminic acid (DANA) have been shown to bind to the conserved active site and to reduce virus infection in animals when administered by nasal spray. Inhibitors of this type are, however, rapidly excreted from physiological systems and may not be effective in order to provide long-time protection. A new class of specific NA inhibitors, which are benzoic acid derivatives, has been designed on the basis of the three-dimensional structure of the NA-DANA complex and modeling of derivatives of 4-(acetylamino)benzoic acid in the NA active site. Intermediates were synthesized and were shown to moderately inhibit the NA activity and to ...
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 ...
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。
[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
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
Enzymes are indispensable for signal transduction and cell regulation, often via kinases and phosphatases. Viruses can also contain enzymes for infecting cells, such as the HIV integrase and reverse transcriptase, or for viral release from cells, like the influenza virus neuraminidase. Protease, also called proteinase, peptidase, or proteolytic enzyme, is any enzyme that performs proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in a polypeptide chain. Proteases have evolved to perform these reactions by numerous different mechanisms. Kinase is an enzyme that catalyzes the transfer of phosphate groups from high-energy, phosphate-donating molecules to specific substrates. Kinases are critical in metabolism, cell signalling, protein regulation, cellular transport, secretory processes, and many other cellular pathways. ...
Yu, M., Wang, Y., Tian, L., Wang, Y., Wang, X., Liang, W., . . . Fang, X. (2015). Safflomin A inhibits neuraminidase activity and influenza virus replication. RSC Adv., 5(114), 94053-94066. doi:10.1039/c5ra17336a ...
EC 3.2.1.18; recommended name: exo‐α‐sialidase; former name: neuraminidase; a glycosidase enzyme that hydrolyses 2,3‐, 2,6‐, and 2,8‐glucosidic linkages joining terminal nonreducing N‐ or O‐acylneuraminyl residues to galactose, N‐acetylhexosamine, or N‐ or O‐acylated neuraminyl residues in oligosaccharides, glycoproteins, or glycolipids.. [...] ...
Encontre virus com ótimos preços e condições na Saraiva. Temos A História da Humanidade Contada Pelos Vírus, Zika Virus Disease - From Origin To Outbreak e muito mais.
sialidase or neuraminidase (EC 3.2.1.18); trans-sialidase (EC 2.4.1.-); anhydrosialidase (EC 4.2.2.15); Kdo hydrolase (EC 3.2.1.-); 2-keto-3-deoxynononic acid hydrolase / KDNase (EC 3.2.1.- ...
Melbourne, Australia 19 April 2007- Biota Holdings Limited (ASX BTA) today announced that its long acting neuraminidase inhibitor (LANI), CS8958, an anti-influe
Scientists have developed a universal cure for the flu 2016. The new drug is effective since it destroys the virus proteins, ie hemagglutinin and neuraminidase. American ...
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mze:101484100 K12357 sialidase-2/3/4 [EC:3.2.1.18] , (RefSeq) neu4; neuraminidase 4 (A) MRSPYFPARSVLFHKEPNGVTYRVPALLYLPRSRSFLAFCEERLSPSDSQAHLLVVRKGT FYRSYVEWEDIRVLGTAFLPGHRSMNPCPVYDEFTGTLFLFFIAVLGHTSESYQLVTGKN VTRLCYVSSTDDGDTWSPVTDLTKKVIGDTIKEWATFALGPGHGIQLKSGRLLIPAYAYH IECKECFGHLCQTTPHSFCFHSDTHGRTWRFGEAVPGPETVECQMVSVDEEDGTNVLYCN ARSPLGYRVQALSLDDGAVFQEGQLVQRLVEPRNGCHGSIIGFPAPLNLCQSLSNDLQRP VRLSRHWTSCTTESSLSKSSTSSVAFSVSANSSSTTSSIPPPHEAPPDFLTPTWVVYSHP TWTTARKNLGLFLSLFPRDPDSWRGPWVIYDGPSAYSDLAYLELSPSPGAPPAVAFACLF ECGTKTAYDEICFSIFTLYELIDNLPRDVWLETNNEGHRKQQGGSCRHDAQSAAVSQQVT PVKKRRKKSKLAEMCSVS ...
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 ...
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 ...
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
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 ...