Oseltamivir-resistant H1N1 influenza viruses carrying the H275Y neuraminidase mutation predominated worldwide during the 2007-2009 seasons. Although several neuraminidase substitutions were found to be necessary to counteract the adverse effects of H275Y, the order and impact of evolutionary events involved remain elusive. Here we reconstruct H1N1 neuraminidase phylogeny during 1999-2009, estim...

The role of the enzyme neuraminidase in pathogenicity of the bacillus Erysipelothrix rhusiopathiae was studied. Different substances with low and high molecular weight were tested as inducers of E. rhusiopathiae neuraminidase biosynthesis. It was found that macromolecular complexes induce the secretion of the enzyme. K(M) values for different substrates showed that the affinity of the E. rhusio...

Pandemic (H1N1) influenza poses an imminent threat. Nations have stockpiled inhibitors of the influenza protein neuraminidase in hopes of protecting their citizens, but drug-resistant strains have already emerged, and novel therapeutics are urgently needed. In the current work, the computer program AutoGrow is used to generate novel predicted neuraminidase inhibitors. Given the great flexibilit...

A gene from Streptococcus pneumoniae was cloned in lambda EMBL301 and then expressed in Escherichia coli, which cleaved the fluorogenic neuraminidase substrate 2'-(4-methylumbelliferyl)-alpha-d-N-acetylneuraminic acid. The cloned gene therefore encodes an enzyme with neuraminidase activity. On the basis of restriction mapping and DNA hybridization studies, this gene could be distinguished from ...

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 ...

The genes coding for the surface glycoproteins hemagglutinin-neuraminidase (HN) of the peste des petits ruminants virus (PPRV) and hemagglutinin (H) of rinderpest virus (RPV) were cloned in a cytomagalovirus promoter driven expression vector and expressed transiently in mammalian cells. The protein expression was apparent 24 h after transfection and the expressed proteins were detected at the c...

When influenza virus was mixed with antisera to its surface subunits before inoculation of cell cultures, anti-hemagglutinin antibodies neutralized infectivity but anti-neuraminidase did not. When the antisera were added after infection of cell cultures, anti-hemagglutinin and anti-neuraminidase antibodies were equally effective in reducing virus titers in culture fluids. Decreased virus titers...

background and aims: each year, the influenza virus causes moderate to severe infections with a high prevalence throughout the world. accordingly, an influenza vaccine that ensures protection with only a single dose would be a much more cost effective approach to influenza prophylaxis. generation of influenza non-replicating virus-like particles (vlp) in baculoviral expression system is an attr...

In this article, we present evidence that sialic acid-containing surface components play a role in the regulation of erythropoiesis. A 1-hr exposure of mouse bone marrow cells to high concentrations of neuraminidase reduced erythroid colony formation. Coculture of 10(6) untreated thymocytes with neuraminidase-treated bone marrow cells restored erythroid colony growth. Neuraminidase-treated thym...

The enzymes neuraminidase (EC 3.2.1.18) and acylneuraminate pyruvate lyase (EC 4.1.3.3) were found in a strain of vibrio falling into Heiberg's group II isolated from a patient with diarrhea. The neuraminidase of this strain resembles the neuraminidase of Vibrio cholerae. The pH-optimum, activation by Ca-ions and heat inactivation were studied. There is also some indication of an immunologicall...