Serial analysis of gene expression (SAGE) in bovine trypanotolerance: preliminary results

In Africa, trypanosomosis is a tsetse-transmitted disease which represents the most important constraint to livestock production. Several indigenous West African taurine (Bos taurus) breeds, such as the Longhorn (N'Dama) cattle are well known to control trypanosome infections. This genetic ability named "trypanotolerance" results from various biological mechanisms under multigenic control. The methodologies used so far have not succeeded in identifying the complete pool of genes involved in trypanotolerance. New post genomic biotechnologies such as transcriptome analyses are efficient in characterising the pool of genes involved in the expression of specific biological functions. We used the serial analysis of gene expression (SAGE) technique to construct, from Peripheral Blood Mononuclear Cells of an N'Dama cow, 2 total mRNA transcript libraries, at day 0 of a Trypanosoma congolense experimental infection and at day 10 post-infection, corresponding to the peak of parasitaemia. Bioinformatic comparisons in the bovine genomic databases allowed the identification of 187 up- and down- regulated genes, EST and unknown functional genes. Identification of the genes involved in trypanotolerance will allow to set up specific microarray sets for further metabolic and pharmacological studies and to design field marker-assisted selection by introgression programmes

Morphometrics as an Insight Into Processes Beyond Tooth Shape Variation in a Bank Vole Population

Phenotype variation is a key feature in evolution, being produced by development and the target of the screening by selection. We focus here on a variable morphological feature: the third upper molar (UM3) of the bank vole, aiming at identifying the sources of this variation. Size and shape of the UM3 occlusal surface was quantified in successive samples of a bank vole population. The first source of variation was the season of trapping, due to differences in the age structure of the population in turn affecting the wear of the teeth. The second direction of variation corresponded to the occurrence, or not, of an additional triangle on the tooth. This intra-specific variation was attributed to the space available at the posterior end of the UM3, allowing or not the addition of a further triangle.This size variation triggering the shape polymorphism is not controlled by the developmental cascade along the molar row. This suggests that other sources of size variation, possibly epigenetic, might be involved. They would trigger an important shape variation as side-effect by affecting the termination of the sequential addition of triangles on the tooth

Tif1? controls the TGF-? receptor on hematopoietic stem cells: implication in physiological aging

Hematopoietic stem cell (HSC) aging has been directly linked to the development of several hematological disorders including myeloproliferative diseases. We recently described that in elderly mice (20-month-old), physiological aging of the hematopoietic system is associated with a decreased expression of the Transcription Intermediary Factor 1? (Tif1?) gene in HSCs. In young mice (4-month-old), deleted for the Tif1? gene in HSCs (Tif1?-/-), the hematopoiesis aging phenotype is intensified. We discovered that Tif1? controls the TGF-b receptor 1 (Tgfbr1) and finely regulates the number of myeloid-restricted HSCs in bone marrow. Altogether, we established that young Tif1?-/- mice develop a phenotype of premature hematopoietic aging, which may explain their tendency to myeloproliferative disease. We identified two populations of HSCs specifically discriminated by Tgfbr1 expression and afforded evidence of the capture of myeloid-restricted (Tgfbr1hi) and myeloid-lymphoid-balanced (Tgfbr1lo) HSC. In conclusion, our study proves that Tif1? can regulate the balance between lymphoid and myeloid HSCs, through a modulation of the TGF-b signaling

Les Polyphénols de la Pomme aux Cidres: diversité variétale et procédés, facteurs clé de la modulation des saveurs et des couleurs

National audienc

Les Polyphénols de la pomme aux cidres : diversité variétale et procédés, facteurs clé de la modulation des saveurs et des couleurs

article présenté lors du colloque 'Phytomicronutriments' qui s’est tenu à Avignon le 16 décembre 2014.National audienceThe French cider is made from apple varieties that are clearly distinguished from dessert apples on the basis of their high concentration in phenolic compounds which are distributed into several classes with varying proportions and with very specific properties. Being concretely involved in the flavours, colour and colloidal stability, these polyphenols and their varietal diversity are an undeniable asset that cider producers can use to diversify the range of products they offer and improve their attractiveness in relation to the current consumer preferences. The Rosé cider made from red-fleshed apple varieties is an example of a product that now appeals to the consumers. Producers can also use effective technologies to selectively modulate the levels of such and such classes of polyphenols responsible for flavours and colours. Genetic variability, structural diversity, biochemical and chemical reactivity related to the oxidation capacity and association with proteins and polysaccharides, perceptions of bitterness and astringency and impact of cider processes are all issues involving the phenolic compounds which are discussed in this review article.Le cidre français est élaboré à partir variétés de pommes qui se distinguent notamment des pommes de table par leur richesse en composés phénoliques répartis en plusieurs catégories en proportions variables et avec des propriétés bien spécifiques. En étant concrètement impliqués dans les saveurs, la couleur et la stabilité colloïdale, ces polyphénols et leur diversité variétale sont un atout incontestable que les producteurs de cidre peuvent utiliser pour diversifier la gamme des produits qu’ils proposent et améliorer leur attractivité en lien avec les préférences actuelles des consommateurs. Le cidre rosé élaboré à partir de variétés de pomme à chair rouge est un exemple de produit qui plait actuellement. Les producteurs disposent aussi de moyens technologiques efficaces pour moduler de façon sélective les teneurs en telles ou telles catégories de polyphénols responsables des saveurs et des couleurs. Variabilité génétique, diversité structurale, réactivité biochimique et chimique vis-à-vis de l’oxydation, capacité d’association avec protéines et polysaccharides, perceptions de l’amertume et de l’astringence et impact des procédés cidricoles sont autant d’éléments impliquant les composés phénoliques qui sont discutés dans cet article de façon synthétique

Schematic representation of the evo-devo model proposed to explain the polymorphism in the UM3 shape.

<p>The formation of each triangle is controlled by a signalling centre (colour-filled circle) surrounded by an inhibitory field (black circle); the subsequent triangle can only develop outside this inhibitory field. (A) Intra-population variation in the bank vole is not related to a change in the spacing of the triangles (hypothesized as related to a change in the dimension of the inhibitory field during the tooth development), but to the termination of the process towards the posterior end of the tooth: an additional triangle will form if enough space is available. (B) In contrast, differences between species such as <i>M. rufocanus</i> and <i>M. rutilus</i> are related to a change in the spacing of the triangles.</p

Shape variation of the third upper molar in the bank vole.

<p>(A) Shape variation of the third upper molar in the bank vole, represented on the first two principal axes of a PCA on the Fourier coefficients of the molar outline. Each grey dot corresponds to a specimen; the mean (+/− the confidence interval) of the four successive periods of trapping have been superimposed to the total variation (red squares  =  Autumn, blue circles  =  Spring). (B) Reconstructed outlines visualising shape variations along the first and second axes.</p