The endocytic Ashwell-Morell receptor (AMR) of hepatocytes detects pathogen remodeling of host glycoproteins by neuraminidase in the bloodstream and mitigates the lethal coagulopathy of sepsis. We have investigated the mechanism of host protection by the AMR during the onset of sepsis and in response to the desialylation of blood glycoproteins by the NanA neuraminidase of Streptococcus pneumoni...

Bacterial neuraminidases increase the adhesiveness in suspension of freshly trypsinized hamster fibroblasts (BHK21 cells). The effect is seen most clearly when the enzymes are added to pre-aggregated suspensions, but can also be observed when cells in monolayer culture are pre-incubated with neuraminidase, suspended, and then aggregated in its absence. BHK21 cells transformed by polyoma virus r...

Antibody-dependent enhancement (ADE) of dengue virus infection occurs when neutralizing antibodies at sub-neutralizing concentrations or non-neutralizing antibodies form complexes with the virus. These virus-antibody complexes can then attach to a Fc gamma receptor-bearing cell, via the Fc portion of the immunoglobulin, resulting in an increased number of infected cells. ADE may be responsible ...

The emergence of a novel H7N9 avian influenza that infects humans is a serious cause for concern. Of the genome sequences of H7N9 neuraminidase available, one contains a substitution of arginine to lysine at position 292, suggesting a potential for reduced drug binding efficacy. We have performed molecular dynamics simulations of oseltamivir, zanamivir and peramivir bound to H7N9, H7N9-R292K, a...

UNLABELLED Objective. A novel avian influenza A virus (AIV) H7N9 subtype which emerged in China in 2013 caused worldwide concern. Deletion of amino-acids 69 to 73 in the neuraminidase stalk was its most notable characteristic. This study is aimed to discuss the tropism and virulence effects of this deletion. METHODS Neuraminidase gene sequences of N9 subtype were collected from NCBI and GISAI...

Neuraminidase treatment of human fetal liver or adult marrow cells prior to culture results in an increased number of erythroid colonies and bursts. No increase occurs in the number of nonerythroid colonies. The number of bursts having more than eight subunits is increased preferentially. Individual burst subunits are also enlarged. Neuraminidase-treated cells yield erythroid bursts when cultur...

In this study, a novel, simple and rapid hemagglutination assay by using a peanut lectin to detect a neuraminidase activity in strains of the Bacteroides fragilis group was developed. One hundred and fourteen species of the B. fragilis group isolated from children with and without diarrhea and 15 reference strains were evaluated. Neuraminidase production was determined by using the method above...

A list of 27 promising antiviral drugs is proposed for use against the H1N1pdm strain. Since the binding site of the H1N1pdm neuraminidase is similar to that of the bird flu H5N1, an effective means to quickly identify top candidates for use against H1N1pdm is to use known bird-flu drugs and the 27 compounds from the NCI diversity set which bind best to H5N1 neuraminidase. These compounds serve...

Deletions in the stalk of the influenza neuraminidase (NA) surface protein are associated with increased virulence, but the mechanisms responsible for this enhanced virulence are unclear. Here we use microsecond molecular dynamics simulations to explore the effect of stalk deletion on enzymatic activity, contrasting NA proteins from the A/swine/Shandong/N1/2009 strain both with and without a st...

A rapid and simple assay method for determining neuraminidase activity was investigated fluorometrically with 4-methylumbelliferyl-N-Ac-a-D-neuraminide as a substrate. The time required for performance was less than 3 hr and the activity could be simply measured with a fluorescent spectrophotometer. Neuraminidase activity in culture supernatant of MDCK cell infected with a small quantity of inf...