Here, we find that the low fusogenicity of ENTV envelope protein (Env) is not because of receptor binding, but lies in its intrinsic insensitivity to receptor-mediated triggering for fusion at low pH. Distinct from JSRV, shedding of ENTV surface (SU) subunit into culture medium was not enhanced by a soluble form of receptor, Hyal2 (sHyal2), and sHyal2 was unable to effectively inactivate the ENTV pseudovirions. Remarkably, replacing either
of the two amino acid residues, N191 or S195, located in the ENTV SU with the corresponding JSRV residues, H191 or G195, markedly increased the Env-mediated membrane fusion activity and infection. Reciprocal amino acid substitutions also partly switched the sensitivities of ENTV and JSRV pseudovirions selleck compound to sHya12-mediated SU shedding and inactivation. While N191 is responsible for an extra N-linked glycosylation of ENTV SU relative to that of JSRV, S195 possibly forms Alvocidib inhibitor a hydrogen bond with a surrounding
amino acid residue. Molecular modeling of the pre-fusion structure of JSRV Env predicts that the segment of SU that contains H191 to G195 contacts the fusion peptide and suggests that the H191N and G195S changes seen in ENTV may stabilize its pre-fusion structure against receptor priming and therefore modulate fusion activation by Hya12. In summary, our study reveals critical determinants in the SU subunits of JSRV and ENTV Env proteins that likely regulate their local structures and thereby differential receptor-mediated fusion activation at low pH, and these findings explain, at least in part, their distinct viral infectivity. (C) 2011 Elsevier Inc. All rights reserved.”
“This communication reports a unique example of water-soluble and fluorescent-switchable amphiphilic diarylethene. This compound performs stable vesicle aggregation in water and shows aggregation-dependent emission in its open form. The fluorescence can be effectively switched by alternating between UV and visible light irradiation. This compound thus can stain KB cells for switchable living cell imaging with excellent resistance to fatigue.”
“Objective: Identification of catheter-related bloodstream infection
Navitoclax (CR-BSI) risk factors and determination of whether intervention related to identified risk factors would reduce CR-BSI rates. Design: Prospective, observational, interventional and interrupted time-series study. Setting: Pediatric Intensive Care Unit (PICU) in a university hospital. Methods: During a 7-year period, 609 central venous catheters (CVC) were placed in 389 patients. CR-BSI risk factors were determined by multivariate analysis during two periods (January 2000-November 2002 and January 2003-April 2007). An intervention to reduce identified risk factors was performed after the first period. CR-BSI rates per 1,000 catheters-days were compared during the two periods. Results: The CR-BSI rate was 11.94 [(95% CI 7.94-15.