Etude de la reaction de phenylation par les composes organobismuthiques catalysee par les sels de cuivre

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Trypanosoma cruzi - Derived Sugar Epitopes - Synthesis and Immunology

The protozoan parasite Trypanosoma cruzi is the causative agent of Chagas disease. As of today no effective vaccine has been developed for it. Certain developmental stages of T.cruzi express cell surface oligosaccharides with terminal alpha-galactosyl and rhamnosyl residues, which are believed to be highly immunogenic in humans. The exact structures and sizes of these epitopes are still unknown. Our quest is to shine light on the chemical structures of immunogenic alpha-Gal and alpha-Rha containing mono-, di-, and trisaccharides that are conjugated to a keyhole limpet hemocyanin (KLH) carrier protein through a combination of chemical synthesis and immunological studies. The compounds synthesized were screened for their ability to be recognized by Chagasic antibodies in an enzyme-linked immunosorbent assay (ELISA). The best recognized sugar-KLH conjugates were used to immunize alpha-1,3 Gal T-KO mice, which do not express cell surface proteins with terminal alpha-galactosides, and are therefore a suitable model for humans. We have successfully synthesized and conjugated a library of nine saccharides with terminal alpha-galactosyl or rhamnosyl moieties, which elicit various levels of antibody production in mice. Upon challenge of the immunized mice with lethal doses of live T. cruzi, prolonged survival was observed when compared to the control group. The work presented here has implications for the development of a carbohydrate-based vaccine for Chagas disease

Some coincidence point results for generalized ( ψ , φ ) -weakly contractions in ordered b-metric spaces

© 2015, Roshan et al.; licensee Springer. In this paper we present some coincidence point results for four mappings satisfying generalized (ψ,φ)-weakly contractive condition in the framework of ordered b-metric spaces. Our results extend, generalize, unify, enrich, and complement recently results of Nashine and Samet (Nonlinear Anal. 74:2201-2209, 2011) and Shatanawi and Samet (Comput. Math. Appl. 62:3204-3214, 2011). As an application of our results, periodic points of weakly contractive mappings are obtained. Also, an example is given to support our results