7 research outputs found
The Major Antigenic Membrane Protein of âCandidatus Phytoplasma asterisâ Selectively Interacts with ATP Synthase and Actin of Leafhopper Vectors
Phytoplasmas, uncultivable phloem-limited phytopathogenic wall-less bacteria, represent a major threat to agriculture worldwide. They are transmitted in a persistent, propagative manner by phloem-sucking Hemipteran insects. Phytoplasma membrane proteins are in direct contact with hosts and are presumably involved in determining vector specificity. Such a role has been proposed for phytoplasma transmembrane proteins encoded by circular extrachromosomal elements, at least one of which is a plasmid. Little is known about the interactions between major phytoplasma antigenic membrane protein (Amp) and insect vector proteins. The aims of our work were to identify vector proteins interacting with Amp and to investigate their role in transmission specificity. In controlled transmission experiments, four Hemipteran species were identified as vectors of âCandidatus Phytoplasma asterisâ, the chrysanthemum yellows phytoplasmas (CYP) strain, and three others as non-vectors. Interactions between a labelled (recombinant) CYP Amp and insect proteins were analysed by far Western blots and affinity chromatography. Amp interacted specifically with a few proteins from vector species only. Among Amp-binding vector proteins, actin and both the α and ÎČ subunits of ATP synthase were identified by mass spectrometry and Western blots. Immunofluorescence confocal microscopy and Western blots of plasma membrane and mitochondrial fractions confirmed the localisation of ATP synthase, generally known as a mitochondrial protein, in plasma membranes of midgut and salivary gland cells in the vector Euscelidius variegatus. The vector-specific interaction between phytoplasma Amp and insect ATP synthase is demonstrated for the first time, and this work also supports the hypothesis that host actin is involved in the internalization and intracellular motility of phytoplasmas within their vectors. Phytoplasma Amp is hypothesized to play a crucial role in insect transmission specificity
Reporte del proyecto âIntelliâ
Documento final del Proyecto de AplicaciĂłn Profesional en el que se tuvo como objetivo encontrar la factibilidad comercial de uno de los productos de la empresa Intelli, que se dedica a la fabricaciĂłn de persianas, especĂficamente en el mercado de CentroamĂ©rica. Los alcances de este trabajo son internacionales, ya que la investigaciĂłn se hace desde MĂ©xico hacia los paĂses de CentroamĂ©rica tomando en cuenta informaciĂłn y datos macroeconĂłmicos, turĂsticos y sociales. La investigaciĂłn se realizĂł por medio de bases de datos. Los resultados mĂĄs importantes fueron el descubrimiento de posibles mercados en dicha regiĂłn que tienen tendencias de crecimiento en el sector de la construcciĂłn y en el turismo
γΎ T cell receptor ligands and modes of antigen recognition.: Antigen recognition by gamma delta T cells
RevueInternational audienceT lymphocytes expressing the γΎ-type of T cell receptors (TCRs) for antigens contribute to all aspects of immune responses, including defenses against viruses, bacteria, parasites and tumors, allergy and autoimmunity. Multiple subsets have been individualized in humans as well as in mice and they appear to recognize in a TCR-dependent manner antigens as diverse as small non-peptidic molecules, soluble or membrane-anchored polypeptides and molecules related to MHC antigens on cell surfaces, implying diverse modes of antigen recognition. We review here the γΎ TCR ligands which have been identified along the years and their characteristics, with emphasis on a few systems which have been extensively studied such as human γΎ T cells responding to phosphoantigens or murine γΎ T cells activated by allogeneic MHC antigens. We discuss a speculative model of antigen recognition involving simultaneous TCR recognition of MHC-like and non-MHC ligands which could fit with most available data and shares many similarities with the classical model of MHC-restricted antigen recognition for peptides or lipids by T cells subsets with αÎČ-type TCRs