Étude d’impact : comparaison et analyse des données anthropométriques et biologiques d’enfants d’âge scolaire au Burkina Faso

L’ Initiative des Écoles Amies de la Nutrition (IEAN) est une initiative développée par l'Organisation Mondiale de la Santé (OMS) en 2006 pour contrer le Double Fardeau Nutritionnel (DFN). TRANSNUT est une équipe de professeurs de l’Université de Montréal et Centre collaborateur OMS sur la transition nutritionnelle et le développement. En 2009, il a participé à une étude de base au Burkina Faso, qui a recueilli des données anthropométriques et biologiques des élèves du cours moyen. Cinq ans plus tard, en 2014, de nouvelles données anthropométriques et biologiques ont été recueillies dans les mêmes écoles mais non chez les mêmes élèves. Le but de cette étude est d'analyser les données de 2014 et de comparer les résultats avec ceux de 2009, afin d'évaluer l'impact et l’efficacité de l'initiative. C’est une étude transversale menée dans 12 écoles à Ouagadougou, la capitale du Burkina Faso. Six écoles «intervention» et six écoles «témoin» ont été sélectionnées, en tenant compte de la nature des écoles (privées/publiques) et de leurs zones géographiques (urbaines/périurbaines). L'échantillon total comprenait 651 écoliers (54,7% de filles) âgés de 8 à 14 ans. Des mesures anthropométriques et de la concentration d'hémoglobine ont été effectuées sur tous les enfants, alors que le rétinol sérique a été mesuré dans un sous-échantillon aléatoire de 184 enfants. Le test de t et du Khi Carré ont été utilisés pour la comparaison des moyennes et des proportions. L'âge moyen des enfants était de 11,4 ± 1,1 ans. Les taux d'anémie et de déficience en vitamine A (DVA) étaient respectivement de 35,6% et 26,1%. La prévalence du retard de croissance était de 8,1% et celle de la maigreur, de 8,4%. Chez les filles, 2,8% étaient en surpoids contre 0,9% des garçons (p = 0,036). Moins d'élèves étaient maigres en 2014 (7,2%) par rapport à 2009 (13,7%), et ce résultat était significatif avec p < 0,001. En outre, les carences en micronutriments ont été moins présentes dans les écoles en 2014 par rapport à 2009 (p = 0,007 pour l'anémie, p = 0,044 pour la DVA). Nos résultats ont confirmé une grande amélioration du statut nutritionnel des enfants d’âge scolaire à Ouagadougou. Toutefois, il n’est pas possible présentement d’évaluer jusqu'à quelle mesure l’IEAN a été impliquée dans ces changements, ni d’attribuer ces améliorations à cette initiative uniquement. Les recherches futures doivent être axées sur des études longitudinales pour évaluer de manière plus précise la croissance des mêmes élèves qui font partie des écoles « amies de la nutrition ».The Nutrition-Friendly School Initiative (NFSI) is an initiative developed by the World Health Organization (WHO) in 2006 to counter the Double Burden of Malnutrition (DBM). TRANSNUT is a team of researchers from the University of Montreal, and a WHO collaborating Centre on Nutrition Changes and Development. In 2009, it participated in a baseline study in Burkina Faso, which collected anthropometric and biological data from students aged 7 to 14 years. Five years later, in 2014, new anthropometric and laboratory data were collected in the same schools but not from the same students. The aim of this study is to analyze the data collected in 2014 and to compare the results with those from 2009 in order to assess the impact of the initiative. This is a cross-sectional study conducted in 12 schools in Ouagadougou the capital of Burkina Faso. Six "intervention" schools and six "control" schools were selected, taking into account the nature of schools (private/public) and their geographical area (urban/suburban). The total sample consisted of 651 schoolchildren (54,7% girls) aged 8-14 years old. Anthropometric and hemoglobin measurements were performed on all children, whereas serum retinol was measured in a random sub-sample of 184 children. Independent t-test and chi square tests were used for comparison of means and proportions. Mean age of the children was 11.4 ± 1.1 years. Rates of anemia and vitamin A deficiency (VAD) were 35.6% and 26.1% respectively. The prevalence of stunting was 6.3% and that of thinness, 7.2%. Among girls, 2.8% were overweight compared to 0.9% of boys (p = 0.036). Fewer students were thin in 2014 (7.2%) compared to 2009 (13.7%), and this difference was significant with p < 0.001. Also, micronutrient deficiencies were less present in schools in 2014 in comparison with 2009 (p = 0.007 for anemia, p = 0.044 for VAD). Our results point to a significant improvement in the nutritional status of school children in Ouagadougou. However, it is not currently possible to assess to what extent NSFI was involved in these changes, nor to attribute these improvements to his initiative only. Future research should focus on longitudinal studies to assess more accurately the growth of the same students who are part of “nutrition-friendly” schools

Tubulin polyglutamylation stimulates spastin-mediated microtubule severing

Microtubules with long polyglutamylated C-terminal tails are more prone to severing by spastin, establishing the importance of tubulin posttranslational modifications

Basal body stability and ciliogenesis requires the conserved component Poc1

Centrioles are the foundation for centrosome and cilia formation. The biogenesis of centrioles is initiated by an assembly mechanism that first synthesizes the ninefold symmetrical cartwheel and subsequently leads to a stable cylindrical microtubule scaffold that is capable of withstanding microtubule-based forces generated by centrosomes and cilia. We report that the conserved WD40 repeat domain–containing cartwheel protein Poc1 is required for the structural maintenance of centrioles in Tetrahymena thermophila. Furthermore, human Poc1B is required for primary ciliogenesis, and in zebrafish, DrPoc1B knockdown causes ciliary defects and morphological phenotypes consistent with human ciliopathies. T. thermophila Poc1 exhibits a protein incorporation profile commonly associated with structural centriole components in which the majority of Poc1 is stably incorporated during new centriole assembly. A second dynamic population assembles throughout the cell cycle. Our experiments identify novel roles for Poc1 in centriole stability and ciliogenesis

CSAP localizes to polyglutamylated microtubules and promotes proper cilia function and zebrafish development

The diverse populations of microtubule polymers in cells are functionally distinguished by different posttranslational modifications, including polyglutamylation. Polyglutamylation is enriched on subsets of microtubules including those found in the centrioles, mitotic spindle, and cilia. However, whether this modification alters intrinsic microtubule dynamics or affects extrinsic associations with specific interacting partners remains to be determined. Here we identify the microtubule-binding protein centriole and spindle–associated protein (CSAP), which colocalizes with polyglutamylated tubulin to centrioles, spindle microtubules, and cilia in human tissue culture cells. Reducing tubulin polyglutamylation prevents CSAP localization to both spindle and cilia microtubules. In zebrafish, CSAP is required for normal brain development and proper left–right asymmetry, defects that are qualitatively similar to those reported previously for depletion of polyglutamylation-conjugating enzymes. We also find that CSAP is required for proper cilia beating. Our work supports a model in which polyglutamylation can target selected microtubule-associated proteins, such as CSAP, to microtubule subpopulations, providing specific functional capabilities to these populations.National Institutes of Health (U.S.) (Grant no. GM074746)American Cancer Society. Research Scholar Grant (121776)National Institute of General Medical Sciences (U.S.) (GM088313

Glutamylation of Nap1 modulates histone H1 dynamics and chromosome condensation in Xenopus

Linker histone H1 is required for mitotic chromosome architecture in Xenopus laevis egg extracts and, unlike core histones, exhibits rapid turnover on chromatin. Mechanisms regulating the recruitment, deposition, and dynamics of linker histones in mitosis are largely unknown. We found that the cytoplasmic histone chaperone nucleosome assembly protein 1 (Nap1) associates with the embryonic isoform of linker histone H1 (H1M) in egg extracts. Immunodepletion of Nap1 decreased H1M binding to mitotic chromosomes by nearly 50%, reduced H1M dynamics as measured by fluorescence recovery after photobleaching and caused chromosome decondensation similar to the effects of H1M depletion. Defects in H1M dynamics and chromosome condensation were rescued by adding back wild-type Nap1 but not a mutant lacking sites subject to posttranslational modification by glutamylation. Nap1 glutamylation increased the deposition of H1M on sperm nuclei and chromatin-coated beads, indicating that charge-shifting posttranslational modification of Nap1 contributes to H1M dynamics that are essential for higher order chromosome architecture