“
“To examine the range of selective processes that potentially operate when poorly binding influenza viruses adapt to replicate more efficiently in alternative environments, we passaged a virus containing an attenuating mutation in the hemagglutinin (HA) receptor binding

site in mice and characterized the resulting mutants with respect to the structural locations of mutations selected, the replication phenotypes of the viruses, and their binding properties on glycan microarrays. The initial attenuated virus had a tyrosine-to-phenylalanine mutation at HA1 position 98 (Y98F), located in the receptor binding pocket, but viruses that were selected contained second-site pseudoreversion mutations in various structural locations that revealed a range of molecular mechanisms for modulating receptor binding that go beyond the

scope that is generally mapped using receptor specificity mutants. A comparison of virus titers LY2874455 cell line in the mouse respiratory tract versus MDCK cells in culture showed that the mutants displayed distinctive replication properties depending on the system, but all were less attenuated in mice than the Y98F virus. An analysis of receptor binding properties confirmed that the initial Y98F virus bound poorly to several different species of erythrocytes, while all mutants reacquired various degrees of hemagglutination activity. Interestingly, both the Y98F virus and Selleckchem PCI-32765 pseudoreversion mutants were shown to bind very inefficiently to standard glycan microarrays containing an abundance of binding substrates for most influenza viruses that have been characterized to date, provided by the Consortium for Functional Glycomics. The viruses were also examined on a recently developed microarray containing glycans terminating in sialic acid derivatives,

and limited binding to a potentially interesting subset of glycans was revealed. The results are discussed with respect to mechanisms for HA-mediated receptor binding, as well as regarding the species of molecules that may act as receptors for influenza virus on host cell surfaces.”
“Acylpeptide hydrolase (ACPH), a serine protease present in the central nervous system (CNS), is believed to have a function in modulating synaptic plasticity, check cleavage of beta amyloid peptide and degradation of aggregated oxidized proteins. In this report, we demonstrate for the first time the presence of ACPH in the synapse and its preferential localization at the pre-synaptic side. We isolated subcellular fractions from the rat telencephalon enriched in pre- versus post-synaptic components by using differential centrifugation steps to evaluate ACPH catalytic activity and expression level. Relative ACPH levels were determined by Western blot techniques while antibodies against synaptophysin and PSD-95 were used as positive pre- and post-synaptic markers, respectively.