Heart of endosymbioses : transcriptomics reveals a conserved genetic program among arbuscular mycorrhizal, actinorhizal and legume-rhizobial symbioses

To improve their nutrition, most plants associate with soil microorganisms, particularly fungi, to form mycorrhizae. A few lineages, including actinorhizal plants and legumes are also able to interact with nitrogen-fixing bacteria hosted intracellularly inside root nodules. Fossil and molecular data suggest that the molecular mechanisms involved in these root nodule symbioses (RNS) have been partially recycled from more ancient and widespread arbuscular mycorrhizal (AM) symbiosis. We used a comparative transcriptomics approach to identify genes involved in establishing these 3 endosymbioses and their functioning. We analysed global changes in gene expression in AM in the actinorhizal tree C. glauca. A comparison with genes induced in AM in Medicago truncatula and Oryza sativa revealed a common set of genes induced in AM. A comparison with genes induced in nitrogen-fixing nodules of C. glauca and M. truncatula also made it possible to define a common set of genes induced in these three endosymbioses. The existence of this core set of genes is in accordance with the proposed recycling of ancient AM genes for new functions related to nodulation in legumes and actinorhizal plants

Thrombospondins in the heart: potential functions in cardiac remodeling

Cardiac remodeling after myocardial injury involves inflammation, angiogenesis, left ventricular hypertrophy and matrix remodeling. Thrombospondins (TSPs) belong to the group of matricellular proteins, which are non-structural extracellular matrix proteins that modulate cell–matrix interactions and cell function in injured tissues or tumors. They interact with different matrix and membrane-bound proteins due to their diverse functional domains. That the expression of TSPs strongly increases during cardiac stress or injury indicates an important role for them during cardiac remodeling. Recently, the protective properties of TSP expression against heart failure have been acknowledged. The current review will focus on the biological role of TSPs in the ischemic and hypertensive heart, and will describe the functional consequences of TSP polymorphisms in cardiac disease

Etude par chromatografie d'affinite' de la variation chez l'homme pendant une surcharge sodee de l'inhibiteur endogene de la Na-K-ATPase [Affinity chromatographic study of the changes in the endogenous Na+-K+-ATPase inhibitor during sodium loading in man]

Semi-purified dog kidney Na+-K+-ATPase was cross-linked with ovalbumin. This immobilized enzyme was able to hydrolyse ATP and this hydrolysis was ouabain-sensitive. It was then used in batch wise affinity chromatography for the detection of endogenous Na+-K+-ATPase inhibitor in human plasma and urine. Ammonium acetate 1 mM washed off the endogenous Na+-K+-ATPase inhibitor from the immobilized enzyme. The inhibitory activity of the eluate from hypertensive plasma was significantly higher (p less than 0.0025, n = 6) than that of normotensive plasma. Similar results were obtained (n = 3) from human urine eluates during salt loading as compared to control urine