La filière sucrière en Tanzanie : au-delà de l’ajustement

Héritée de la mise en valeur coloniale et des recompositions post-coloniales liées à la politique d’Ujamaa, la filière sucrière tanzanienne doit affronter la récurrence des aléas climatiques, les défis de l’ouverture régionale et de la mondialisation. Les coûts de production élevés pèsent sur la compétitivité du sucre tanzanien. Néanmoins les alter produits constituent une alternative intéressante quoique lointaine à la valorisation de la canne dans le cadre du plan décennal.Inherited from the colonial times and the Ujaama regime, the Tanzanian sugar sector is facing three major challenges : the regular droughts and floods, the regional construction and the economic globalization. However high production costs heavy competiveness. Yet, the next Ten years National Economic Plan presents alter-products from sugar cane transformation as interesting alternatives to sugar

Vietnam national security files, 1961-1963

Bib id: 4775982 "National security files.

The RNA-Binding Protein Unr Prevents Mouse Embryonic Stem Cells Differentiation Toward the Primitive Endoderm Lineage

International audienceThe maintenance of embryonic stem cells (ESCs) pluripotency depends on key transcription factors, chromatin remodeling proteins, and microRNAs. The roles of RNA-binding proteins are however poorly understood. We report that the cytoplasmic RNA-binding protein Unr prevents the differentiation of ESCs into primitive endoderm (PrE). We show that unr knockout (unr(-/-) ) ESCs spontaneously differentiate into PrE, and that Unr re-expression in unr(-/-) ESCs reverses this phenotype. Nevertheless, unr(-/-) ESCs retain pluripotency, producing differentiated teratomas, and the differentiated unr(-/-) ESCs coexpress the PrE inducer Gata6 and the pluripotency factors Oct4, Nanog, and Sox2. Interestingly, in the differentiated unr(-/-) ESCs, Nanog and Sox2 exhibit a dual nuclear and cytoplasmic localization. This situation, that has never been reported, likely reflects an early differentiation state toward PrE. Finally, we show that Unr destabilizes Gata6 mRNAs and we propose that the post-transcriptional repression of Gata6 expression by Unr contributes to the stabilization of the ESCs pluripotent state

An Eighteen-Month Helicobacter Infection Does Not Induce Amyloid Plaques or Neuroinflammation in Brains of Wild Type C57BL/6J Mice

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Alzheimer's disease and Helicobacter pylori infection: inflammation from stomach to brain?

Despite extensive research, the origin of Alzheimer's disease (AD) remains unknown. The role of infectious pathogens has recently emerged. Epidemiological studies have shown that Helicobacter pylori infection increases the risk of developing AD. We hypothesized that H. pylon-induced gastritis may be associated with a systemic inflammation and finally neuroinflammation. C57BL/6 mice were infected with H. pylori (n= 15) or Helicobacter felis (n= 13) or left uninfected (n = 9) during 18 months. Gastritis, amyloid deposition, astroglial and microglial cell area, and systemic and brain cytokines were assessed. The infection (H. felis>H. pylori) induced a severe gastritis and an increased neuroinflammation but without brain amyloid deposition or systemic inflammation

Plasmalogens Regulate Retinal Connexin 43 Expression and Müller Glial Cells Gap Junction Intercellular Communication and Migration

International audiencePlasmalogens are a specific glycerophospholipid subtype characterized by a vinyl-ether bound at their sn- 1 moiety. Their biosynthesis is initiated in the peroxisome by dihydroxyacetone phosphate-acyltransferase (DHAPAT), which is encoded by the DAPAT gene. Previous studies have shown that plasmalogen-deficient mice exhibit major physiological dysfunctions including several eye defects, among which abnormal vascular development of the retina and a reactive activation of macroglial Müller cells. Interestingly, plasmalogen deficiency in mice is also associated with a reduced expression of brain connexin 43 (Cx43). Cx43 is the main connexin subtype of retinal glial cells and is involved in several cellular mechanisms such as calcium-based gap junction intercellular communication (GJIC) or cell migration. Thus, the aim of our work was 1) to confirm the alteration of Cx43 expression in the retina of plasmalogen-deficient DAPAT −/- mice and 2) to investigate whether plasmalogens are involved in crucial functions of Müller cells such as GJIC and cell migration. First, we found that plasmalogen deficiency was associated with a significant reduction of Cx43 expression in the retina of DAPAT −/- mice in vivo . Secondly, using a siRNA targeting DHAPAT in vitro , we found that a 50%-reduction of Müller cells content in plasmalogens was sufficient to significantly downregulate Cx43 expression, while increasing its phosphorylation. Furthermore, plasmalogen-depleted Müller cells exhibited several alterations in ATP-induced GJIC, such as calcium waves of higher amplitude that propagated slower to neighboring cells, including astrocytes. Finally, in vitro plasmalogen depletion was also associated with a significant downregulation of Müller cells migration. Taken together, these data confirm that plasmalogens are critical for the regulation of Cx43 expression and for characteristics of retinal Müller glial cells such as GJIC and cell migration

Behavioural responses to a photovoltaic subretinal prosthesis implanted in non-human primates

International audienceRetinal dystrophies and age-related macular degeneration related to photoreceptor degeneration can cause blindness. In blind patients, although the electrical activation of the residual retinal circuit can provide useful artificial visual perception, the resolutions of current retinal prostheses have been limited either by large electrodes or small numbers of pixels. Here we report the evaluation, in three awake non-human primates, of a previously reported near-infrared-light-sensitive photovoltaic subretinal prosthesis. We show that multipixel stimulation of the prosthesis within radiation safety limits enabled eye tracking in the animals, that they responded to stimulations directed at the implant with repeated saccades and that the implant-induced responses were present two years after device implantation. Our findings pave the way for the clinical evaluation of the prosthesis in patients affected by dry atrophic age-related macular degeneration