Effect of cooking temperature and cooking time on Warner-Bratzler tenderness measurement and collagen content in rabbit meat

International audienc

Caractérisation physico-chimique et rhéologique de la viande de lapin. Application à la comparaison de lapins label et standard

National audienceDeux lots de 48 lapins issus de systèmes d'élevage différents (Standard et Label) âgés respectivement de 10 et 13 semaines mais de même poids vif (2,35 kg) ont été étudiés au moyen, d'une part, de mesures de cisaillement sur du muscle Longissimus dorsi (LD) cru et cuit avec détermination de la perte de jus à la cuisson, et d'autre part, de mesures TOBEC et de mesures des teneurs en lipides totaux et matières sèches sur les muscles de la cuisse. Les mesures de cisaillement permettent de différencier les 2 lots lorsqu'elles sont effectuées sur LD crus. Par contre sur LD cuits aucune différence n'est mise en évidence entre les 2 lots. La perte à la cuisson se révèle être la mesure la plus significative pour différencier les 2 populations. Les analyses chimiques et les mesures TOBEC ne permettent pas de distinguer les 2 lots. Enfin, l'absence de corrélation entre les mesures TOBEC et la teneur en lipides ne nous permet pas de valider cette nouvelle technique pour estimer la teneur en lipides de broyats de viande

Oral infection with the parasite Toxoplasma gondii, a model for inflammatory bowel disease ?

National audienc

The TL MHC class Ib molecule has only marginal effects on the activation, survival and trafficking of mouse small intestinal intraepithelial lymphocytes

International audienceThymus leukemia antigen (TL) is an MHC class Ib molecule that is highly conserved in rats and mice with no obvious human homolog. TL is expressed in mouse small intestinal epithelial cells and is known to interact with CD8alphaalpha homodimers, which are expressed by intraepithelial lymphocytes (IELs), some other T cell subsets and some non-T cells such as a subset of dendritic cells. We show here that TL is abundantly expressed on the basolateral surface of mouse small intestinal epithelial cells and that expression is abrogated in beta2m-/- mice but unaffected in TCR-/- mice or CD8alpha chain-/- mice. We demonstrate that the interaction between TL and CD8alphaalpha is not necessary for IEL survival in vitro or in vivo and does not modulate IEL trafficking in vivo. TL co-stimulation of alpha-CD3 antibody-activated IELs resulted in modestly enhanced production of IFN-gamma in one subset of IELs. The lack of effect on IEL survival and trafficking and the modest effect on IFN-gamma production suggest that the functional consequences of TL interaction with CD8alphaalpha as well as the more general biological role of TL in mucosal immunity remains to be discovered

Effect of selection on body size at fixed age on muscle characteristics in rabbit

National audienc

Tendreté mécanique du muscle longissimus dorsi de lapin : étude méthodologique

National audienc

Effects of jump training on passive mechanical stress and stiffness in rabbit skeletal muscle : role of collagen

International audienc

Effect of selection on body size at fixed age on muscle characteristics in rabbit

National audienc

CD11c- and CD11b-expressing mouse leukocytes transport single Toxoplasma gondii tachyzoites to the brain

The protozoan parasite Toxoplasma gondii enters hosts through the intestinal mucosa and colonizes distant tissues such as the brain, where its progeny persists for a lifetime. We investigated the role of CD11c- and CD11b-expressing leukocytes in T gondii transport during the early step of parasitism from the mouse small intestine and during subsequent parasite localization in the brain. Following intragastric inoculation of cyst-containing parasites in mice, CD11c+ dendritic cells from the intestinal lamina propria, the Peyer patches, and the mesenteric lymph nodes were parasitized while in the blood, parasites were associated with the CD11c- CD11b+ monocytes. Using adoptive transfer experiments, we demonstrated that these parasitized cells triggered a parasitic process in the brain of naive recipient mice. Ex vivo analysis of parasitized leukocytes showed that single tachyzoites remained at the cell periphery, often surrounded by the host cell plasma membrane, but did not divide. Using either a dye that labels circulating leukocytes or an antibody known to prevent CD11b+ circulating leukocytes from leaving the microvascular bed lumen, and chimeric mice in which the hematopoietic cells expressed the green fluorescent protein, we established that T gondii zoites hijacked CD11b+ leukocytes to reach the brain extravascular space

Extrathymic T Cell Lymphopoiesis

International audienceIn the absence of thymopoiesis, T lymphocytes are nevertheless present, mainly in the gut epithelium. Ontogeny of the extrathymic pathway and the extent of its involvement in euthymic mice are controversial. These questions have been addressed by assessing the expression of recombinase activating gene (RAG) through the use of green fluorescent protein RAG2 transgenic mouse models. In athymic mice, T lymphopoiesis occurs mainly in the mesenteric lymph node and less in the Peyer's patches. Ontogenic steps of this lymphopoiesis resemble those of thymopoiesis, but with an apparent bias toward ␥␦ T cell production and with a paucity of oligoclonal ␣␤ T cells possibly resulting from a deficit in positive selection. Whether in athymic or euthymic mice, neither T intraepithelial lymphocytes (IEL) nor cryptopatch cells (reported to contain precursors of IEL) displayed fluorescence indicating recent RAG protein synthesis. Newly made T cells migrate from the mesenteric node into the thoracic duct lymph to reach the gut mucosa. In euthymic mice, this extrathymic pathway is totally repressed, except in conditions of severe lymphocytic depletion. Thus, in normal animals, all gut T IEL, including CD8 ␣␣ ϩ cells, are of thymic origin, CD8 ␣␣ ϩ TCR ␣␤ ϩ IEL being the likely progeny of double negative NK1-1 Ϫ thymocytes, which show polyclonal V ␣ and V ␤ repertoires