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Human milk glycans inhibit binding between norovirus and its host glycan receptor; such competitive inhibition by human milk glycans is associated with a reduced risk of infection. The relationship between the presence of specific structural motifs in the human milk glycan and its ability to inhibit binding by specific norovirus strains requires facile, accurate and miniaturized-binding assays. Toward this end, a high-throughput biosensor platform was developed based on surface plasmon resonance imaging (SPRi) of glycan microarrays. The SPRi was validated, and its utility was tested, by measuring binding specificities between defined human milk glycan epitopes and the capsids of two common norovirus strains, VA387 and Norwalk. Human milk oligosaccharide (HMOS)-based neoglycoconjugates, including chemically derived neoglycoproteins and oligosaccharide-glycine derivatives, were used to represent polyvalent glycoconjugates and monovalent oligosaccharides, respectively, in human milk. SPRi binding results established that the glycan motifs that bind norovirus capsids depend upon strain; VA387 capsid interacts with two neoglycoproteins, whereas Norwalk capsid binds to a different set of HMOS motifs in the form of both polyvalent neoglycoproteins and monovalent oligosaccharides. SPRi competitive binding assays further demonstrated that specific norovirus-binding glycans are able to inhibit norovirus capsid binding to their host receptors. A polyvalent neoglycoconjugate with clustered carbohydrate moieties is required for the inhibition of VA387 capsid binding to host receptor glycans, whereas both monovalent oligosaccharides and polyvalent neoglycoconjugates are able to inhibit Norwalk capsid binding to its host receptor. Binding of HMOS and HMOS-based neoglycoconjugates to norovirus capsids depends upon the specific strain characteristics, implying that HMOS and their polyvalent derivatives are potential anti-adhesive agents for norovirus prophylaxis. [ABSTRACT FROM PUBLISHER]

This work aims to obtain new transformations and auto-Bäcklund transformations for generalized Liouville equations with exponential nonlinearity having a factor depending on the first derivatives. This paper discusses the construction of Bäcklund transformations for nonlinear partial second-order derivatives of the soliton type with logarithmic nonlinearity and hyperbolic linear parts. The construction of transformations is based on the method proposed by Clairin for second-order equations of the Monge–Ampere type. For the equations studied in the article, using the Bäcklund transformations, new equations are found, which make it possible to find solutions to the original nonlinear equations and reveal the internal connections between various integrable equations. [ABSTRACT FROM AUTHOR]

Alkoxy(trimethylsiloxy)phosphines like (IV) are obtained by reaction of alkyl hypophosphites, prepared in situ, with N-trimethylsilylsuccinimide (III). [ABSTRACT FROM AUTHOR]

Abstract: The tubular immunostimulating complex (TI-complex) is a novel nanoparticulate antigen delivery system consisting of cholesterol, triterpene glycoside cucumarioside A2-2, and glycolipid monogalactosyldiacylglycerol (MGDG) isolated from marine macrophytes. MGDG is crucial for the formation of a lipid matrix for the protein antigen incorporated in TI-complexes. Fatty acid composition and the physical state of this glycolipid depend on the taxonomic position of marine macrophytes. Therefore, the aim of the present work was to study the capacity of MGDGs, isolated from five species of marine macrophytes, to influence conformation and to enhance immunogenicity of porin from Yersinia pseudotuberculosis (YOmpF) as a model antigen of subunit vaccine based on TI-complexes. The trimeric porin was chosen for these experiments, because it was approximately two times more immunogenic than monomeric porin incorporated in TI-complexes. Immunization of mice with YOmpF within TI-complexes, comprised of different MGDGs, revealed a dependence of the immunostimulating effect of TI-complexes on the microvicosity of this glycolipid. TI-complexes comprising MGDGs from Sargassum pallidum and Ulva fenestrata with medium microviscosity induced maximal levels of anti-porin antibodies (four times higher when compared with those induced by pure porin). The adjuvant effect of TI-complexes based on other MGDGs varied by 2.8, 2.3 and 1.3 times for TI-complexes comprised of MGDGs from Zostera marina, Ahnfeltia tobuchiensis, and Laminaria japonica, respectively. MGDGs are also able to influence cytokine mechanisms of immunological regulation. DSC and spectroscopic studies showed that maximal immunostimulating effect of TI-complexes correlated with a moderate stabilizing influence of MGDGs from S. pallidum and U. fenestrata on the conformation of porin. The results obtained suggest lipid “nanofluidics” as a novel strategy for optimizing the immune response to protein antigens within lipid particulate systems. [Copyright &y& Elsevier]

• The new methylenediphosphonates with non-proteinogenic amino acid and aminosulfonic acid moieties are synthesized in the presence of Me 3 SiOTf as a catalyst. • The catalytic schema of the resulting compounds syntheses include the formation of highly reactive iminium salts. • The target substances are structural analogues of well-known drugs and may be considered as promising polydentate ligands, antibacterial and antiviral compounds. The new non-proteinogenic amino acids with methylenebisphosphonic acids moieties are synthesized for the first time via unique reaction of tris(trimethylsilyl) phosphite and various N -formyl amino acids at the presence of effective catalyst – trimethylsilyl triflate under mild conditions. The further treatment of initially formed trimethylsilyl intermediates with the methanol excess resulted in the water-soluble non-proteinogenic amino acids with methylenebisphosphonic acids moieties in high yields. The catalytic scheme of target substances formation is proposed and discussed in detail. The structures of target functionalized amino acids and their precursors were confirmed by the 1H, 13C, 31P NMR spectra and high resolution mass spectra. The resulted compounds are of great interest as promising antiviral substances and effective ligands. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The literature data on X substituent influence on the 1H, 29Si and 15N NMR chemical shifts (δ) and coupling constants (J) of Si-substituted silatranes ▪, as well as M–N bond lengths (d) in atranes ▪ (M=C, Si, Ge, Sn, Pb) have been analyzed. It was established for the first time that the δ, J and d values depend not only on the inductive and resonance effects but also on the polarizability of X substituents. The polarizability contribution ranges from 8% to 25%. [Copyright &y& Elsevier]

Bacterium Yersinia ruckeri as a pathogen induces causative agent of intestinal fish disease called enteric redmouth disease (ERM) is known. In this study, outer membrane OmpF porin from the Y. ruckeri (YrOmpF) has been identified as a pathogenic factor which affects host macrophage activation and life cycle of eukaryotic cells. Using synthetic peptides corresponding to the sequences of the outer loops of YrOmpF L1 loop of the porin is most involved in the structure of B epitopes on the surface of the microbial cell it was found. T epitopes of the isolated YrOmpF trimer not only by linear, but also by discontinuous determinants, which is due to the secondary structure of the protein are represented. It was shown that YrOmpF was twice more cytotoxic to THP-1 cells (human monocytes, cancer cells) in comparison with CHH-1 cells (Oncorhynchus keta cardiac muscle cell, non-cancer cells). It was found YrOmpF induce cell cycle S-phase arrest in both normal CHH-1 and cancer THP-1 cells. In the cancer cells observed effect was most pronounce. In addition, we have observed an induction of apoptosis in THP-1 cell line treated with YrOmpF for 48 h at IC 50 (48.6 μg/ml). Significant cytotoxic effect of YrOmpF on primary mouse peritoneal macrophages been detected as well. Of note, co-incubation of macrophages with anti-YrOmpF antibodies could decrease the amount of lactate dehydrogenase, while the number of living cells significantly increased. YrOmpF stimulates the activity of the phagocytic bactericidal systems especially of the oxygen-independent subsystem it was found. Antibodies against YrOmpF decreased MPO release and CP synthesis by peritoneal macrophages and increased their viability. Image 1 • The outer loops of YrOmpF are involved in the formation of T and B antigenic epitopes. • YrOmpF induces cell cycle S-phase arrest and apoptosis in THP-1 cells. • Toxic effects of Y. ruckeri and YrOmpF on macrophages is reduced by anti-porin antibodies. • YrOmpF regulates the activity of murine peritoneal macrophages bactericidal systems. • Antibodies against YrOmpF enhanced synthesis of cationic proteins. [ABSTRACT FROM AUTHOR]

The convenient silicon-assisted synthesis of new aminomethylenebisphosphonic acids and their precursors was developed via unique methodology. So new aminomethylenebisphosphonic acids with quinolines moieties were obtained using suitable reaction of tris(trimethylsilyl) phosphite and N -formyl aminoquinolines catalyzed by trimethylsilyl triflate under mild conditions (20 °C). The initially formed intermediates – tetra (trimethylsilyl) aminomethylenebisphosphonates are transformed to target acids by methanolysis in high yields. The catalytic scheme of target substances formation is proposed and discussed in detail. The structures of aminomethylenebisphosphonic acids and their precursors with substituted quinoline moieties were confirmed by the 1H, 13C, 31P NMR spectra and high resolution mass spectra. Image 1 • The new quinolyl aminomethylenediphosphonates are synthesized in the presence of Me 3 SiOTf as a catalyst. • The resulting substances are structural analogues of well-known drugs and may be considered as promising polydentate ligands and plant growth regulating agents. [ABSTRACT FROM AUTHOR]

The new convenient synthesis of functionalized aryl and pyridyl aminomethylenebisphosphonic acids and their derivatives has been developed via silicon-assisted methodology. New functionalized aminomethylenebisphosphonic acids containing pyridines moieties were obtained using unique reaction of tris(trimethylsilyl) phosphite with N -formyl aminopyridines and trimethylsilyl triflate as a catalyst under mild conditions. Intermediates – tetra(trimethylsilyl) aminomethylenebisphosphonates formed, were converted to the target acids by further treatment with methanol excess. In contrast the corresponding tetraethyl aminomethylenebisphosphonates were synthesized under heating (130 °C) of four component mixture (diethyl trimethylsilyl phosphite, triethyl orthoformate, aryl- or pyridylamine, and diethyl phosphite) in the presence of zinc chloride catalyst. The catalytic schemes of target substances formation are proposed and thoroughly discussed. Image 1 • The new aryl and pyridyl aminomethylenediphosphonates are synthesized in the presence of Me 3 SiOTf or ZnCl 2 as catalysts.. • The catalytic schemes of the target compounds synthesis include the formation of highly reactive iminium salts. • The resulting substances are structural analogues of well-known drugs and may be considered as promising polydentate ligands. [ABSTRACT FROM AUTHOR]